JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Defective Innate Immunity and Hyper-Inflammation in Newborn CFTR-Knockout Ferret Lungs.
Am. J. Respir. Cell Mol. Biol.
PUBLISHED: 10-16-2014
Show Abstract
Hide Abstract
Mucociliary clearance (MCC) and submucosal glands (SMGs) are major components of airway innate immunity that have impaired function in cystic fibrosis (CF). Although both of these defense systems develop post-natally in the ferret, the lungs of newborn ferrets remain sterile in the presence of a functioning cystic fibrosis transmembrane conductance regulator (CFTR) gene. We evaluated several components of airway innate immunity and inflammation in the early CF ferret lung. At birth, the rates of MCC did not differ between CF and non-CF animals, but the height of the airway surface liquid was significantly reduced in CF newborn ferrets. CF ferrets had impaired MCC after 7 days of age, despite normal rates of ciliogenesis. Only non-CF ferrets eradicated Pseudomonas directly introduced into the lung after birth, while both genotypes could eradicate Staphylococcus. CF bronchioalveolar lavage fluid (BALF) had significantly lower and selective antimicrobial activity against Pseudomonas than non-CF, which was insensitive to changes in pH and bicarbonate. LC-MS-MS and cytokine analysis of BALF from sterile C-sectioned and non-sterile naturally-born animals demonstrated CF-associated disturbances in IL-8, TNF?, and IL-?, and pathways that control immunity and inflammation including the complement system, macrophage functions, mTOR signaling, and eIF2 signaling. Interestingly, during the birth transition, IL-8 was selectively induced in CF BALF, despite no genotypic difference in bacterial load shortly after birth. These results suggest that newborn CF ferrets have defects in both innate immunity and inflammatory signaling that may be important in the early onset and progression of lung disease in these animals.
Related JoVE Video
Impact of estrogen receptor (ER) and human epidermal growth factor receptor-2 (HER2) co-expression on breast cancer disease characteristics: implications for tumor biology and research.
Breast Cancer Res. Treat.
PUBLISHED: 08-29-2014
Show Abstract
Hide Abstract
ER and HER2 are critical drivers of breast cancer biology and can interact when co-expressed, but less data describe the impact of ER/HER2 co-expression on clinical disease characteristics. We studied the impact of ER and HER2 (co)-expression in a cohort of 1,187 patients with invasive breast cancer and compared disease characteristics among different groups according to ER and HER2 status. Age, tumor size, grade, nodal status, TNM stage, and metastatic sites were compared and significance determined using the appropriate t tests. All p values were two-tailed. Compared to ER-negative/HER2-negative disease as the control group, ER expression was associated with older age, smaller tumors, lower grade, earlier TNM stage, and increased bone involvement in de novo metastasis, while HER2 had no significant impact on these characteristics. ER and HER2 co-expression was associated with lower grade and higher bone involvement in de novo metastasis, reflecting a retained impact for ER. HER2 impact on ER-positive disease was reflected by younger age, higher grade and TNM stage, and increased frequency of visceral involvement in de novo metastasis. Within the ER-positive/HER2-positive group, triple positive breast cancer (ER+/PgR+/HER2+) was associated with younger age compared to ER+/PgR-/HER2+ disease (mean age of 50.8 vs. 56 years, p = 0.0226). PgR was also associated with younger age in ER+/HER2- disease with a mean age of 57.6 years in ER+/PgR+/HER2- disease vs. 63.4 years in ER+/PgR-/HER2- disease (p < 0.0001). In conclusion, ER has a profound impact on breast cancer characteristics, including a retained impact when co-expressed with HER2. Similarly, HER2 dramatically modulates ER-positive breast cancer making it more aggressive. PgR association with young age may be related to hormonal levels of the premenopausal state, with HER2 providing an earlier growth advantage in triple positive disease, suggesting a specific dependence for this subset on high estrogen levels.
Related JoVE Video
Supramolecular assembly of asymmetric self-neutralizing amphiphilic peptide wedges.
Langmuir
PUBLISHED: 07-25-2014
Show Abstract
Hide Abstract
Mimicking the remarkable dynamic and multifunctional utility of biological nanofibers, such as microtubules, is a challenging and technologically attractive objective in synthetic supramolecular chemistry. Understanding the complex molecular interactions that govern the assembly of synthetic materials, such as peptides, is key to meeting this challenge. Using molecular dynamics simulations to guide molecular design, we explore here the self-assembly of structurally and functionally asymmetric wedge-shaped peptides. Supramolecular assembly into nanofiber gels or multilayered lamellar structures was determined by cooperative influences of hydrogen bonding, amphiphilicity (hydrophilic asymmetry), and the distribution of electrostatic charges on the aqueous self-assembly of asymmetric peptides. Molecular amphiphilicity and ?-sheet forming capacity were both identified as necessary, but not independently sufficient, to form supramolecular nanofibers. Imbalances in positive and negative charges prevented nanofiber assembly, while the asymmetric distribution of balanced charges within a peptide is believed to affect peptide conformation and subsequent self-assembly into either nanofibers or lamellar structures. Insights into cooperative molecular interactions and the effects of molecular asymmetry on assembly may aid the development of next-generation supramolecular nanomaterial assemblies.
Related JoVE Video
Protecting trauma patients from duplicated computed tomography scans: the relevance of integrated care systems.
Am. J. Surg.
PUBLISHED: 07-23-2014
Show Abstract
Hide Abstract
Duplicated computed tomography (CT) scans in transferred trauma patients have been described in university-based trauma systems. This study compares CT utilization between a university-based nonintegrated system (NIS) and a vertically integrated regional healthcare system (IS).
Related JoVE Video
Electrostatically tuned self-assembly of branched amphiphilic peptides.
J Phys Chem B
PUBLISHED: 07-03-2014
Show Abstract
Hide Abstract
Electrostatics plays an important role in the self-assembly of amphiphilic peptides. To develop a molecular understanding of the role of the electrostatic interactions, we develop a coarse-grained model peptide and apply self-consistent field theory to investigate the peptide assembly into a variety of aggregate nanostructures. We find that the presence and distribution of charged groups on the hydrophilic branches of the peptide can modify the molecular configuration from extended to collapsed. This change in molecular configuration influences the packing into spherical micelles, cylindrical micelles (nanofibers), or planar bilayers. The effects of charge distribution therefore have important implications for the design and utility of functional materials based on peptides.
Related JoVE Video
Carbon dioxide and hydrogen sulfide associations with regional bacterial diversity patterns in microbially induced concrete corrosion.
Environ. Sci. Technol.
PUBLISHED: 06-16-2014
Show Abstract
Hide Abstract
The microbial communities associated with deteriorating concrete corrosion fronts were characterized in 35 samples taken from wastewater collection and treatment systems in ten utilities. Bacterial communities were described using Illumina MiSeq sequencing of the V1V2 region of the small subunit ribosomal ribonucleic acid (SSU-rRNA) gene recovered from fresh corrosion products. Headspace gas concentrations (hydrogen sulfide, carbon dioxide, and methane), pore water pH, moisture content, and select mineralogy were tested for correlation to community outcomes and corrosion extent using pairwise linear regressions and canonical correspondence analysis. Corroding concrete was most commonly characterized by moisture contents greater than 10%, pore water pH below one, and limited richness (<10 taxa). Bacterial community composition was not correlated to geographic location when considered independently from other environmental factors. Corrosion was most severe in sites with high levels of hydrogen sulfide (>100 ppm) and carbon dioxide (>1%) gases, conditions which also were associated with low diversity biofilms dominated by members of the acidophilic sulfur-oxidizer genus Acidithiobacillus.
Related JoVE Video
Recent introduction of an allodapine bee into Fiji: A new model system for understanding biological invasions by pollinators.
Insect Sci.
PUBLISHED: 04-23-2014
Show Abstract
Hide Abstract
Morphology-based studies have suggested a very depauperate bee fauna for islands in the South West Pacific, and recent genetic studies since have indicated an even smaller endemic fauna with many bee species in this region resulting from human-aided dispersal. These introduced species have the potential to both disrupt native pollinator suites as well as augment crop pollination, but for most species the timings of introduction are unknown. We examined the distribution and nesting biology of the long-tongued bee Braunsapis puangensis that was first recorded from Fiji in 2007. This bee has now become widespread in Fiji and both its local abundance and geographical range are likely to increase dramatically. The impacts of this invasion are potentially enormous for agriculture and native ecosystems, but they also provide opportunities for understanding how social insect species adapt to new environments. We outline the major issues associated with this recent invasion and argue that a long-term monitoring study is needed.
Related JoVE Video
Self-assembly of chiral tubules.
Soft Matter
PUBLISHED: 03-22-2014
Show Abstract
Hide Abstract
The efficient and controlled assembly of complex structures from macromolecular building blocks is a critical open question in both biological systems and nanoscience. Using molecular dynamics simulations we study the self-assembly of tubular structures from model macromolecular monomers with multiple binding sites on their surfaces [Cheng et al., Soft Matter, 2012, 8, 5666-5678]. In this work we add chirality to the model monomer and a lock-and-key interaction. The self-assembly of free monomers into tubules yields a pitch value that often does not match the chirality of the monomer (including achiral monomers). We show that this mismatch occurs because of a twist deformation that brings the lateral interaction sites into alignment when the tubule pitch differs from the monomer chirality. The energy cost for this deformation is small as the energy distributions substantially overlap for small differences in the pitch and chirality. In order to control the tubule pitch by preventing the twist deformation, the interaction between the vertical surfaces must be increased without resulting in kinetically trapped structures. For this purpose, we employ lock-and-key interactions and obtain good control of the self-assembled tubule pitch. These results explain some fundamental features of microtubules. The vertical interaction strength is larger than the lateral in microtubules because this yields a controlled assembly of tubules with the proper pitch. We also generally find that the control of the assembly into tubules is difficult, which explains the wide range of pitch values and protofilament numbers observed in microtubule assembly.
Related JoVE Video
Growth, motility and resistance to oxidative stress of the melioidosis pathogen Burkholderia pseudomallei are enhanced by epinephrine.
Pathog Dis
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Burkholderia pseudomallei causes melioidosis, a severe invasive disease endemic in South-East Asia and Northern Australia. Bacterial pathogens of several genera have been reported to be able to sense and respond to the stress-related catecholamine hormone epinephrine. Here, we report that epinephrine induces growth of B. pseudomallei in minimal serum-rich medium and heat-inactivated whole human serum and enhances bacterial motility, transcription of flagellar genes and flagellin synthesis. The effect of epinephrine on motility, but not bacterial growth, could be partially reversed by the alpha-adrenergic receptor antagonist phentolamine. Epinephrine also altered the transcription of iron-regulated genes encoding superoxide dismutase (sodB) and the malleobactin receptor (fmtA). Consistent with induction of sodB expression, epinephrine-treated B. pseudomallei exhibited increased resistance to superoxide. Epinephrine treatment did not stimulate Type III secretion via the virulence-associated Bsa apparatus or the ability of B. pseudomallei to invade epithelial cells in culture. This study provides the first evidence that epinephrine, a hormone released from the host under stress and upon therapy, can affect B. pseudomallei virulence-associated properties.
Related JoVE Video
Use of complementary and alternative medical therapies (CAM) by patients attending a regional comprehensive cancer care centre.
J Complement Integr Med
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
This study determined the prevalence, types, and attitudes towards complementary and alternative medicines (CAMs) and therapies in cancer patients actively undergoing conventional cancer treatment at a regional cancer centre.
Related JoVE Video
Hydrogen-bonded aggregates in precise acid copolymers.
J Chem Phys
PUBLISHED: 02-12-2014
Show Abstract
Hide Abstract
We perform atomistic molecular dynamics simulations of melts of four precise acid copolymers, two poly(ethylene-co-acrylic acid) (PEAA) copolymers, and two poly(ethylene-co-sulfonic acid) (PESA) copolymers. The acid groups are spaced by either 9 or 21 carbons along the polymer backbones. Hydrogen bonding causes the acid groups to form aggregates. These aggregates give rise to a low wavevector peak in the structure factors, in agreement with X-ray scattering data for the PEAA materials. The structure factors for the PESA copolymers are very similar to those for the PEAA copolymers, indicating a similar distance between aggregates which depends on the spacer length but not on the nature of the acid group. The PEAA copolymers are found to form more dimers and other small aggregates than do the PESA copolymers, while the PESA copolymers have both more free acid groups and more large aggregates.
Related JoVE Video
Analysis of immune responses induced by avian pathogenic Escherichia coli infection in turkeys and their association with resistance to homologous re-challenge.
Vet. Res.
PUBLISHED: 02-05-2014
Show Abstract
Hide Abstract
Avian pathogenic Escherichia coli (APEC) cause severe respiratory and systemic disease in poultry yet the nature and consequences of host immune responses to infection are poorly understood. Here, we describe a turkey sub-acute respiratory challenge model and cytokine, cell-mediated and humoral responses associated with protection against homologous re-challenge. Intra-airsac inoculation of turkeys with 105 colony-forming units of APEC O78:H9 strain ?7122nalR induced transient and mild clinical signs of colibacillosis followed by clearance of the bacteria from the lungs and visceral organs. Upon re-challenge with 107 ?7122nalR, primed birds were solidly protected against clinical signs and exhibited negligible bacterial loads in visceral organs, whereas age-matched control birds exhibited high lesion scores and bacterial loads in the organs. Levels of mRNA for signature cytokines suggested induction of a Th1 response in the lung, whereas a distinct anti-inflammatory cytokine profile was detected in the liver. Proliferative responses of splenocytes to either Concanavalin A or soluble ?7122nalR antigens were negligible prior to clearance of bacteria, but APEC-specific responses were significantly elevated at later time intervals and at re-challenge relative to control birds. Primary infection also induced significantly elevated ?7122nalR-specific serum IgY and bile IgA responses which were bactericidal against ?7122nalR and an isogenic ?rfb mutant. Bactericidal activity was observed in the presence of immune, but not heat-inactivated immune serum, indicating that the antibodies can fix complement and are not directed solely at the lipopolysaccharide O-antigen. Such data inform the rational design of strategies to control a recalcitrant endemic disease of poultry.
Related JoVE Video
Novosphingobium and its potential role in chronic obstructive pulmonary diseases: insights from microbiome studies.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Bacterial infection of lung airways underlies some of the main complications of COPD, significantly impacting disease progression and outcome. Colonization by bacteria may further synergize, amplify, or trigger pathways of tissue damage started by cigarette smoke, contributing to the characteristic airway inflammation and alveolar destruction of COPD. We sought to elucidate the presence and types of lung bacterial populations in different stages of COPD, aimed at revealing important insights into the pathobiology of the disease. Sequencing of the bacterial small subunit ribosomal RNA gene in 55 well-characterized clinical lung samples, revealed the presence of Novosphingobium spp. (>2% abundance) in lungs of patients with GOLD 3-GOLD 4 COPD, cystic fibrosis and a subset of control individuals. Novosphingobium-specific quantitative PCR was concordant with the sequence data and high levels of Novosphingobium spp. were quantifiable in advanced COPD, but not from other disease stages. Using a mouse model of subacute lung injury due to inhalation of cigarette smoke, bronchoalveolar lavage neutrophil and macrophage counts were significantly higher in mice challenged intratracheally with N. panipatense compared to control mice (p<0.01). Frequencies of neutrophils and macrophages in lung tissue were increased in mice challenged with N. panipatense at room air compared to controls. However, we did not observe an interaction between N. panipatense and subacute cigarette smoke exposure in the mouse. In conclusion, Novosphingobium spp. are present in more severe COPD disease, and increase inflammation in a mouse model of smoke exposure.
Related JoVE Video
Specific microbiome changes in a mouse model of parenteral nutrition associated liver injury and intestinal inflammation.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Parenteral nutrition (PN) has been a life-saving treatment in infants intolerant of enteral feedings. However, PN is associated with liver injury (PN Associated Liver Injury: PNALI) in a significant number of PN-dependent infants. We have previously reported a novel PNALI mouse model in which PN infusion combined with intestinal injury results in liver injury. In this model, lipopolysaccharide activation of toll-like receptor 4 signaling, soy oil-derived plant sterols, and pro-inflammatory activation of Kupffer cells (KCs) played key roles. The objective of this study was to explore changes in the intestinal microbiome associated with PNALI.
Related JoVE Video
Analysis of the prevalence, secretion and function of a cell cycle-inhibiting factor in the melioidosis pathogen Burkholderia pseudomallei.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Enteropathogenic and enterohaemorrhagic Escherichia coli express a cell cycle-inhibiting factor (Cif), that is injected into host cells via a Type III secretion system (T3SS) leading to arrest of cell division, delayed apoptosis and cytoskeletal rearrangements. A homologue of Cif has been identified in Burkholderia pseudomallei (CHBP; Cif homologue in B. pseudomallei; BPSS1385), which shares catalytic activity, but its prevalence, secretion and function are ill-defined. Among 43 available B. pseudomallei genome sequences, 33 genomes (76.7%) harbor the gene encoding CHBP. Western blot analysis using antiserum raised to a synthetic CHBP peptide detected CHBP in 46.6% (7/15) of clinical B. pseudomallei isolates from the endemic area. Secretion of CHBP into bacterial culture supernatant could not be detected under conditions where a known effector (BopE) was secreted in a manner dependent on the Bsa T3SS. In contrast, CHBP could be detected in U937 cells infected with B. pseudomallei by immunofluorescence microscopy and Western blotting in a manner dependent on bsaQ. Unlike E. coli Cif, CHBP was localized within the cytoplasm of B. pseudomallei-infected cells. A B. pseudomallei chbP insertion mutant showed a significant reduction in cytotoxicity and plaque formation compared to the wild-type strain that could be restored by plasmid-mediated trans-complementation. However, there was no defect in actin-based motility or multinucleated giant cell formation by the chbP mutant. The data suggest that the level or timing of CHBP secretion differs from a known Bsa-secreted effector and that CHBP is required for selected virulence-associated phenotypes in vitro.
Related JoVE Video
Parallel responses of bees to Pleistocene climate change in three isolated archipelagos of the southwestern Pacific.
Proc. Biol. Sci.
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The impacts of glacial cycles on the geographical distribution and size of populations have been explored for numerous terrestrial and marine taxa. However, most studies have focused on high latitudes, with only a few focused on the response of biota to the last glacial maximum (LGM) in equatorial regions. Here, we examine how population sizes of key bee fauna in the southwest Pacific archipelagos of Fiji, Vanuatu and Samoa have fluctuated over the Quaternary. We show that all three island faunas suffered massive population declines, roughly corresponding in time to the LGM, followed by rapid expansion post-LGM. Our data therefore suggest that Pleistocene climate change has had major impacts across a very broad tropical region. While other studies indicate widespread Holarctic effects of the LGM, our data suggest a much wider range of latitudes, extending to the tropics, where these climate change repercussions were important. As key pollinators, the inferred changes in these bee faunas may have been critical in the development of the diverse Pacific island flora. The magnitude of these responses indicates future climate change scenarios may have alarming consequences for Pacific island systems involving pollinator-dependent plant communities and agricultural crops.
Related JoVE Video
Distribution and diversity of soil microfauna from East Antarctica: assessing the link between biotic and abiotic factors.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Terrestrial life in Antarctica has been described as some of the simplest on the planet, and mainly confined to soil microfaunal communities. Studies have suggested that the lack of diversity is due to extreme environmental conditions and thought to be driven by abiotic factors. In this study we investigated soil microfauna composition, abundance, and distribution in East Antarctica, and assessed correlations with soil geochemistry and environmental variables. We examined 109 soil samples from a wide range of ice-free habitats, spanning 2000 km from Framnes Mountains to Bailey Peninsula. Microfauna across all samples were patchily distributed, from complete absence of invertebrates to over 1600 specimens/gram of dry weight of soil (gdw), with highest microfauna abundance observed in samples with visible vegetation. Bdelloid rotifers were on average the most widespread found in 87% of sampled sites and the most abundant (44 specimens/gdw). Tardigrades occurred in 57% of the sampled sites with an abundance of 12 specimens/gdw. Nematodes occurred in 71% of samples with a total abundance of 3 specimens/gdw. Ciliates and mites were rarely found in soil samples, with an average abundance of 1.3 and 0.04 specimens/gdw, respectively. We found that microfaunal composition and abundance were mostly correlated with the soil geochemical parameters; phosphorus, NO3 (-) and salinity, and likely to be the result of soil properties and historic landscape formation and alteration, rather than the geographic region they were sampled from. Studies focusing on Antarctic biodiversity must take into account soil geochemical and environmental factors that influence population and species heterogeneity.
Related JoVE Video
VASCULAR ALTERATIONS IN THE SPRAGUE-DAWLEY RAT MANDIBLE DURING INTRAVENOUS BISPHOSPHONATE THERAPY.
J Oral Implantol
PUBLISHED: 12-04-2013
Show Abstract
Hide Abstract
Abstract Long-term use of intravenous bisphosphonates, such as zoledronic acid (zoledronate), has been linked to bisphosphonate-related osteonecrosis of the jaw (BRONJ). Invasive dental surgery seems to trigger the bone necrosis in most cases. Purpose: To determine the effects of zoledronic acid on the vascular structure of the rat mandible. Methods and Materials: Extracted of the mandibular first molar in rats that received two IV injections of zoledronate (20 µg/kg), 4 weeks apart. Zoledronate-treated rats (n=18) were then compared to a control group of untreated rats (n=18). At the 4th, 8th, and 12th week after molar extraction, eight rat mandibles from each group were perfused with 35% radiopaque triphenylbismuth in methyl methacrylate via carotid artery perfusion. Mandibles were harvested and examined by micro-CT to assess the spatial and dimensional changes of the vasculature as a result of zoledronate treatment. Results: The micro-CT analysis showed that zoledronic acid-treated rats had blood vessels that were thicker, less connected, and less ordered than control rats that were not exposed to zoledronic acid. Conclusions: This study demonstrated that treatment with zoledronic acid in rats is associated with vascular changes in alveolar bone. Further studies are underway to explore whether these vascular changes contribute to the pathogenesis of BRONJ.
Related JoVE Video
Suicides - United States, 2005-2009.
MMWR Surveill Summ
PUBLISHED: 11-23-2013
Show Abstract
Hide Abstract
Injury from self-directed violence, which includes suicidal behavior and its consequences, is a leading cause of death and disability. In 2009, suicide was the 10th-leading cause of death in the United States and the cause of 36,909 deaths. In 2005, the estimated cost of self-directed violence (fatal and nonfatal treated) was $41.2 billion (including $38.9 billion in productivity losses and $2.2 billion in medical costs). Suicide is a complex human behavior that results from an interaction of multiple biological, psychological, social, political, and economic factors. Although self-directed violence affects members of all racial/ethnic groups in the United States, it often is misperceived to be a problem affecting primarily non-Hispanic white males.
Related JoVE Video
Homicides - United States, 2007 and 2009.
MMWR Surveill Summ
PUBLISHED: 11-23-2013
Show Abstract
Hide Abstract
According to 1981-2009 data, homicide accounts for 16,000-26,000 deaths annually in the United States and ranks within the top four leading causes of death among U.S. residents aged 1-40 years. Homicide can have profound long-term emotional consequences on families and friends of victims and on witnesses to the violence, as well as cause excessive economic costs to residents of affected communities. For years, homicide rates have been substantially higher among certain populations. Previous reports have found that homicides are higher among males, adolescents and young adults, and certain racial/ethnic groups, such as non-Hispanic blacks, non-Hispanic American Indian/Alaska Natives (AI/ANs), and Hispanics. The 2011 CDC Health Disparities and Inequalities Report (CHDIR) described similar findings for the year 2007. For example, the 2011 report showed that the 2007 homicide rate was highest among non-Hispanic blacks (23.1 deaths per 100,000), followed by AI/ANs (7.8 deaths per 100,000), Hispanics (7.6 deaths per 100,000), non-Hispanic whites (2.7 deaths per 100,000), and Asian/Pacific Islanders (A/PIs) (2.4 deaths per 100,000). In addition, non-Hispanic black men aged 20-24 years were at greatest risk for homicide in 2007, with a rate that exceeded 100 deaths per 100,000 population. Other studies have reported that community factors such as poverty and economic inequality and individual factors such as unemployment and involvement in criminal activities can play a substantial role in these persistent disparities in homicide rates. Public health strategies are needed in communities at high risk for homicide to prevent violence and save lives.
Related JoVE Video
A phase II study of combined fulvestrant and everolimus in patients with metastatic estrogen receptor (ER)-positive breast cancer after aromatase inhibitor (AI) failure.
Breast Cancer Res. Treat.
PUBLISHED: 10-28-2013
Show Abstract
Hide Abstract
Fulvestrant, which degrades ER, is used after AI failure in metastatic breast cancer but resistance develops quickly. We hypothesized that using everolimus to inhibit mTOR, a key signaling pathway in endocrine resistance, may delay fulvestrant resistance in patients and thus improve its efficacy. We conducted a phase II trial of combined fulvestrant and everolimus in postmenopausal women with disease progression or relapse after an AI. Primary endpoint was time to progression (TTP) and secondary endpoints included objective response rate, clinical benefit rate (CBR), safety, and biomarker correlates. Tumor blocks were collected and biopsy of accessible tumor was done for future biomarker analysis. Of 33 patients enrolled two were ruled ineligible after enrollment and were excluded from study analysis, for a total of 31 evaluable patients. Median age was 54 years (range 45-85). Prior therapy included tamoxifen (81 %), chemotherapy (71 %), with 26 % of patients having received 3 or more endocrine agents. Median TTP was 7.4 months (95 % CI 1.9-12.1) with an objective response rate of 13 % and CBR of 49 %. Of particular note, 32 % of patients exhibited de novo resistance to study treatment with disease progression as their best response. Most common adverse events (AEs) were elevated AST (87 %) and ALT (77 %), anemia (74 %), hyperglycemia (71 %), and hypercholesterolemia (68 %). Prominent clinical toxicities were mucositis (58 %), weight loss (48 %), and rash (42 %). Most AEs were grade 1 or 2 and largely reversible with infrequent need for everolimus dose reduction. To conclude, everolimus plus fulvestrant is effective after AI failure in heavily pretreated metastatic ER-positive breast cancer and has manageable toxicity. Further study of this combination is warranted in randomized studies. Since not all patients experience benefit, and in view of potential toxicities, biomarker examination is critical to help select patients most likely to benefit from this strategy in future studies.
Related JoVE Video
Discrete model studies of two grafted polyelectrolyte polymer hydrogels pressed in contact.
J Chem Phys
PUBLISHED: 10-15-2013
Show Abstract
Hide Abstract
The interaction between two grafted polymer gels was investigated. We studied a defect-free network of diamond-like topology containing 8 tetra-functional nodes linked by 16 non-crossing chains. In order to explain the very low friction coefficient observed for polyelectrolyte hydrogels, we computed the monomer density profile of these polymer gels, the interpenetration between two polymer gels (defined as the percentage of monomers belonging to one gel which have penetrated the second gel), the normal force per unit area, and the radial distribution function of the interacting monomers. Low monomer density in the interface region separating the two gels and low interpenetration of the gels similar to that found in our simulations are likely to be responsible for the small friction coefficients observed for polyelectrolyte polymer gels.
Related JoVE Video
Study of the structure dependent behavior of polyelectrolyte in water.
J Chem Phys
PUBLISHED: 09-21-2013
Show Abstract
Hide Abstract
We examine the effect of pendant architecture on linear polyelectrolytes in solution using molecular dynamics simulations. A comparison is done between the standard bead-spring polyelectrolyte system and a system which has the charged beads pendant to neutral backbone beads. Recent simulations of ionomer melts have found significant differences in the structure between the two architectures, but we find the structure is not dramatically affected by the different geometry. In general, the backbone architecture is slightly more compact than the pendant architecture. The counterion condensation is typically larger for the backbone systems, which yields the more compact structures. Only when both the Bjerrum length is much larger than the spacing between charges and the spacing between pendants is twice the backbone bead spacing, is the peak in the monomer-counterion radial distribution function larger for the pendant architecture. The radius of gyration for the pendant remains larger than backbone architecture because of the extra excluded volume of the pendant.
Related JoVE Video
Restricted mitochondrial protein acetylation initiates mitochondrial autophagy.
J. Cell. Sci.
PUBLISHED: 09-04-2013
Show Abstract
Hide Abstract
Because nutrient-sensing nuclear and cytosolic acetylation mediates cellular autophagy, we investigated whether mitochondrial acetylation modulates mitochondrial autophagy (mitophagy). Knockdown of GCN5L1, a component of the mitochondrial acetyltransferase machinery, diminished mitochondrial protein acetylation and augmented mitochondrial enrichment of autophagy mediators. This program was disrupted by SIRT3 knockdown. Chronic GCN5L1 depletion increased mitochondrial turnover and reduced mitochondrial protein content and/or mass. In parallel, mitochondria showed blunted respiration and enhanced stress-resilience. Genetic disruption of autophagy mediators Atg5 and p62 (also known as SQSTM1), as well as GCN5L1 reconstitution, abolished deacetylation-induced mitochondrial autophagy. Interestingly, this program is independent of the mitophagy E3-ligase Parkin (also known as PARK2). Taken together, these data suggest that deacetylation of mitochondrial proteins initiates mitochondrial autophagy in a canonical autophagy-mediator-dependent program and shows that modulation of this regulatory program has ameliorative mitochondrial homeostatic effects.
Related JoVE Video
Molecular analysis of point-of-use municipal drinking water microbiology.
Water Res.
PUBLISHED: 08-29-2013
Show Abstract
Hide Abstract
Little is known about the nature of the microbiology in tap waters delivered to consumers via public drinking water distribution systems (DWDSs). In order to establish a broader understanding of the microbial complexity of public drinking waters we sampled tap water from seventeen different cities between the headwaters of the Arkansas River and the mouth of the Mississippi River and determined the bacterial compositions by pyrosequencing small subunit rRNA genes. Nearly 98% of sequences observed among all systems fell into only 5 phyla: Proteobacteria (35%), Cyanobacteria (29%, including chloroplasts), Actinobacteria (24%, of which 85% were Mycobacterium spp.), Firmicutes (6%), and Bacteroidetes (3.4%). The genus Mycobacterium was the most abundant taxon in the dataset, detected in 56 of 63 samples (16 of 17 cities). Among the more rare phylotypes, considerable variation was observed between systems, and was sometimes associated with the type of source water, the type of disinfectant, or the concentration of the environmental pollutant nitrate. Abundant taxa (excepting Cyanobacteria and chloroplasts) were generally similar from system to system, however, regardless of source water type or local land use. The observed similarity among the abundant taxa between systems may be a consequence of the selective influence of chlorine-based disinfection and the common local environments of DWDS and premise plumbing pipes.
Related JoVE Video
Modular tagging of amplicons using a single PCR for high-throughput sequencing.
Mol Ecol Resour
PUBLISHED: 05-28-2013
Show Abstract
Hide Abstract
High-throughput sequencing (HTS) of PCR amplicons is becoming the method of choice to sequence one or several targeted loci for phylogenetic and DNA barcoding studies. Although the development of HTS has allowed rapid generation of massive amounts of DNA sequence data, preparing amplicons for HTS remains a rate-limiting step. For example, HTS platforms require platform-specific adapter sequences to be present at the 5 and 3 end of the DNA fragment to be sequenced. In addition, short multiplex identifier (MID) tags are typically added to allow multiple samples to be pooled in a single HTS run. Existing methods to incorporate HTS adapters and MID tags into PCR amplicons are either inefficient, requiring multiple enzymatic reactions and clean-up steps, or costly when applied to multiple samples or loci (fusion primers). We describe a method to amplify a target locus and add HTS adapters and MID tags via a linker sequence using a single PCR. We demonstrate our approach by generating reference sequence data for two mitochondrial loci (COI and 16S) for a diverse suite of insect taxa. Our approach provides a flexible, cost-effective and efficient method to prepare amplicons for HTS.
Related JoVE Video
Comprehensive assignment of roles for Salmonella typhimurium genes in intestinal colonization of food-producing animals.
PLoS Genet.
PUBLISHED: 04-01-2013
Show Abstract
Hide Abstract
Chickens, pigs, and cattle are key reservoirs of Salmonella enterica, a foodborne pathogen of worldwide importance. Though a decade has elapsed since publication of the first Salmonella genome, thousands of genes remain of hypothetical or unknown function, and the basis of colonization of reservoir hosts is ill-defined. Moreover, previous surveys of the role of Salmonella genes in vivo have focused on systemic virulence in murine typhoid models, and the genetic basis of intestinal persistence and thus zoonotic transmission have received little study. We therefore screened pools of random insertion mutants of S. enterica serovar Typhimurium in chickens, pigs, and cattle by transposon-directed insertion-site sequencing (TraDIS). The identity and relative fitness in each host of 7,702 mutants was simultaneously assigned by massively parallel sequencing of transposon-flanking regions. Phenotypes were assigned to 2,715 different genes, providing a phenotype-genotype map of unprecedented resolution. The data are self-consistent in that multiple independent mutations in a given gene or pathway were observed to exert a similar fitness cost. Phenotypes were further validated by screening defined null mutants in chickens. Our data indicate that a core set of genes is required for infection of all three host species, and smaller sets of genes may mediate persistence in specific hosts. By assigning roles to thousands of Salmonella genes in key reservoir hosts, our data facilitate systems approaches to understand pathogenesis and the rational design of novel cross-protective vaccines and inhibitors. Moreover, by simultaneously assigning the genotype and phenotype of over 90% of mutants screened in complex pools, our data establish TraDIS as a powerful tool to apply rich functional annotation to microbial genomes with minimal animal use.
Related JoVE Video
Culture-independent analysis of aerosol microbiology in a metropolitan subway system.
Appl. Environ. Microbiol.
PUBLISHED: 03-29-2013
Show Abstract
Hide Abstract
The goal of this study was to determine the composition and diversity of microorganisms associated with bioaerosols in a heavily trafficked metropolitan subway environment. We collected bioaerosols by fluid impingement on several New York City subway platforms and associated sites in three sampling sessions over a 1.5-year period. The types and quantities of aerosolized microorganisms were determined by culture-independent phylogenetic analysis of small-subunit rRNA gene sequences by using both Sanger (universal) and pyrosequencing (bacterial) technologies. Overall, the subway bacterial composition was relatively simple; only 26 taxonomic families made up ~75% of the sequences determined. The microbiology was more or less similar throughout the system and with time and was most similar to outdoor air, consistent with highly efficient air mixing in the system. Identifiable bacterial sequences indicated that the subway aerosol assemblage was composed of a mixture of genera and species characteristic of soil, environmental water, and human skin commensal bacteria. Eukaryotic diversity was mainly fungal, dominated by organisms of types associated with wood rot. Human skin bacterial species (at 99% rRNA sequence identity) included the Staphylococcus spp. Staphylococcus epidermidis (the most abundant and prevalent commensal of the human integument), S. hominis, S. cohnii, S. caprae, and S. haemolyticus, all well-documented human commensal bacteria. We encountered no organisms of public health concern. This study is the most extensive culture-independent survey of subway microbiota so far and puts in place pre-event information required for any bioterrorism surveillance activities or monitoring of the microbiological impact of recent subway flooding events.
Related JoVE Video
Diversification of Fijian halictine bees: insights into a recent island radiation.
Mol. Phylogenet. Evol.
PUBLISHED: 03-26-2013
Show Abstract
Hide Abstract
Although bees form a key pollinator suite for flowering plants, very few studies have examined the evolutionary radiation of non-domesticated bees over human time-scales. This is surprising given the importance of bees for crop pollination and the effect of humans in transforming ecosystems via agriculture. In the Pacific, where the bee fauna appears depauperate, their importance as pollinators is not clear, particularly in Fiji where species diversity is even lower than neighbouring archipelagos. Here we explore the radiation of halictine bees in Fiji using phylogenetic analyses of mtDNA COI sequence data. Our analyses indicate the existence of several deep clades whose divergences are close to the crown node, along with a highly derived broom clade showing very high haplotype diversity, and mostly limited to low-lying agricultural regions. This derived clade is very abundant, whereas the more basal clades were relatively rare. Although nearly all haplotype diversity in Fijian Homalictus comprises synonymous substitutions, a small number of amino acid changes are associated with the major clades, including the hyper-diverse clade. Analyses of haplotype lineage accumulation show a steep increase in selectively neutral COI haplotypes corresponding to the emergence of this broom clade. We explore three possible scenarios for this dramatic increase: (i) a key change in adaptedness to the environment, (ii) a large-scale extinction event, or (iii) a dramatic increase in suitable habitats leading to rapid population expansion. Using estimated mutation rates of mitochondrial DNA in other invertebrates, we argue that Homalictus first colonised the Fijian archipelago in the middle-late Pleistocene, and the rapid accumulation of haplotypes in the hyper-diverse clade occurred in the Holocene, but prior to recorded human presence in the Fijian region. Our results indicate that bees have not been important pollinators of Fijian ecosystems until very recent times. Post-Pleistocene climate change and anthropogenic effects on Fijian ecosystems are likely to have greatly transformed pollinator suites from the conditions when those ecosystems were first being assembled.
Related JoVE Video
Process improvement in trauma: traumatic bladder injuries and compliance with recommended imaging evaluation.
J Trauma Acute Care Surg
PUBLISHED: 03-22-2013
Show Abstract
Hide Abstract
We hypothesized that our compliance was low with recommended imaging for evaluation of traumatic bladder injury, which includes either a computed tomographic (CT) cystogram or plain cystogram. We sought to determine if poor compliance impacted diagnosis, management, and outcome of patients with bladder injury.
Related JoVE Video
The role of focused abdominal sonography for trauma (FAST) in pediatric trauma evaluation.
J. Pediatr. Surg.
PUBLISHED: 02-16-2013
Show Abstract
Hide Abstract
With increasing concerns about radiation exposure, we questioned whether a structured program of FAST might decrease CT use.
Related JoVE Video
Process improvement in trauma: compliance with recommended imaging evaluation in the diagnosis of high-grade renal injuries.
J Trauma Acute Care Surg
PUBLISHED: 01-29-2013
Show Abstract
Hide Abstract
Appropriate imaging in renal trauma can avoid delayed recognition of collecting system injuries, allowing for prompt intervention and less morbidity. Current recommendations include obtaining abdominal and pelvic computed tomographic scans with intravenous contrast, followed by excretory images for high-grade injury or perinephric fluid. The purpose of this study was to evaluate compliance with this recommendation among adult Level I trauma centers in Utah.
Related JoVE Video
Molecular phylogeny reveals independent origins of body scales in Entomobryidae (Hexapoda: Collembola).
Mol. Phylogenet. Evol.
PUBLISHED: 01-03-2013
Show Abstract
Hide Abstract
Entomobryidae is the largest family in Collembola but relationships within the family have never been subjected to rigorous phylogenetic analyses. Within the family, body scales are present in many species, and are fundamental in the classification at the subfamilial and tribal levels. A molecular phylogeny was reconstructed using the nuclear 18SrRNA and partial 28SrRNA and the mitochondrial 16SrRNA to examine the evolution of scales across Entomobryidae subfamilies. These datasets were analyzed separately and combined, with parsimony, likelihood and Bayesian algorithms. Monophyly of Orchesellinae was not recovered, and it was split into a scaled clade and an unscaled clade, contradicting to all recent taxonomic conceptions. The monophyly of Entomobryinae, Seirinae and Lepidocyrtinae is well supported however within Entomobryinae, the polyphyly of Entomobryini and Willowsiini implies that classification using the presence/absence of scales is not valid. Analyses of ancestral character state reconstruction in Entomobryidae indicate that the presence of body scales have evolved independently at least five times, with a loss of scales occurring independently at least twice. A revision of the family Entomobryidae on molecular and morphological basis is clearly needed.
Related JoVE Video
Identification of a Predicted Trimeric Autotransporter Adhesin Required for Biofilm Formation of Burkholderia pseudomallei.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The autotransporters are a large and diverse family of bacterial secreted and outer membrane proteins, which are present in many Gram-negative bacterial pathogens and play a role in numerous environmental and virulence-associated interactions. As part of a larger systematic study on the autotransporters of Burkholderia pseudomallei, the causative agent of the severe tropical disease melioidosis, we have constructed an insertion mutant in the bpss1439 gene encoding an unstudied predicted trimeric autotransporter adhesin. The bpss1439 mutant demonstrated a significant reduction in biofilm formation at 48 hours in comparison to its parent 10276 wild-type strain. This phenotype was complemented to wild-type levels by the introduction of a full-length copy of the bpss1439 gene in trans. Examination of the wild-type and bpss1439 mutant strains under biofilm-inducing conditions by microscopy after 48 hours confirmed that the bpss1439 mutant produced less biofilm compared to wild-type. Additionally, it was observed that this phenotype was due to low levels of bacterial adhesion to the abiotic surface as well as reduced microcolony formation. In a murine melioidosis model, the bpss1439 mutant strain demonstrated a moderate attenuation for virulence compared to the wild-type strain. This attenuation was abrogated by in trans complementation, suggesting that bpss1439 plays a subtle role in the pathogenesis of B. pseudomallei. Taken together, these studies indicate that BPSS1439 is a novel predicted autotransporter involved in biofilm formation of B. pseudomallei; hence, this factor was named BbfA, Burkholderia biofilm factor A.
Related JoVE Video
Inflammation and airway microbiota during cystic fibrosis pulmonary exacerbations.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Pulmonary exacerbations (PEx), frequently associated with airway infection and inflammation, are the leading cause of morbidity in cystic fibrosis (CF). Molecular microbiologic approaches detect complex microbiota from CF airway samples taken during PEx. The relationship between airway microbiota, inflammation, and lung function during CF PEx is not well understood.
Related JoVE Video
Ionic aggregate structure in ionomer melts: effect of molecular architecture on aggregates and the ionomer peak.
J. Am. Chem. Soc.
PUBLISHED: 12-19-2011
Show Abstract
Hide Abstract
We perform a comprehensive set of coarse-grained molecular dynamics simulations of ionomer melts with varying polymer architectures and compare the results to experiments in order to understand ionic aggregation on a molecular level. The model ionomers contain periodically or randomly spaced charged beads, placed either within or pendant to the polymer backbone, with the counterions treated explicitly. The ionic aggregate structure was determined as a function of the spacing of charged beads and also depends on whether the charged beads are in the polymer backbone or pendant to the backbone. The low wavevector ionomer peak in the counterion scattering is observed for all systems, and it is sharpest for ionomers with periodically spaced pendant charged beads with a large spacing between charged beads. Changing to a random or a shorter spacing moves the peak to lower wavevector. We present new experimental X-ray scattering data on Na(+)-neutralized poly(ethylene-co-acrylic acid) ionomers that show the same two trends in the ionomer peak, for similarly structured ionomers. The order within and between aggregates, and how this relates to various models used to fit the ionomer peak, is quantified and discussed.
Related JoVE Video
Cucumber mosaic virus and its 2b RNA silencing suppressor modify plant-aphid interactions in tobacco.
Sci Rep
PUBLISHED: 10-10-2011
Show Abstract
Hide Abstract
The cucumber mosaic virus (CMV) 2b protein not only inhibits anti-viral RNA silencing but also quenches transcriptional responses of plant genes to jasmonic acid, a key signalling molecule in defence against insects. This suggested that it might affect interactions between infected plants and aphids, insects that transmit CMV. We found that infection of tobacco with a 2b gene deletion mutant (CMV?2b) induced strong resistance to aphids (Myzus persicae) while CMV infection fostered aphid survival. Using electrical penetration graph methodology we found that higher proportions of aphids showed sustained phloem ingestion on CMV-infected plants than on CMV?2b-infected or mock-inoculated plants although this did not increase the rate of growth of individual aphids. This indicates that while CMV infection or certain viral gene products might elicit aphid resistance, the 2b protein normally counteracts this during a wild-type CMV infection. Our findings suggest that the 2b protein could indirectly affect aphid-mediated virus transmission.
Related JoVE Video
Cysteine 203 of cyclophilin D is critical for cyclophilin D activation of the mitochondrial permeability transition pore.
J. Biol. Chem.
PUBLISHED: 09-19-2011
Show Abstract
Hide Abstract
The mitochondrial permeability transition pore (mPTP) opening plays a critical role in mediating cell death during ischemia/reperfusion (I/R) injury. Our previous studies have shown that cysteine 203 of cyclophilin D (CypD), a critical mPTP mediator, undergoes protein S-nitrosylation (SNO). To investigate the role of cysteine 203 in mPTP activation, we mutated cysteine 203 of CypD to a serine residue (C203S) and determined its effect on mPTP opening. Treatment of WT mouse embryonic fibroblasts (MEFs) with H(2)O(2) resulted in an 50% loss of the mitochondrial calcein fluorescence, suggesting substantial activation of the mPTP. Consistent with the reported role of CypD in mPTP activation, CypD null (CypD(-/-)) MEFs exhibited significantly less mPTP opening. Addition of a nitric oxide donor, GSNO, to WT but not CypD(-/-) MEFs prior to H(2)O(2) attenuated mPTP opening. To test whether Cys-203 is required for this protection, we infected CypD(-/-) MEFs with a C203S-CypD vector. Surprisingly, C203S-CypD reconstituted MEFs were resistant to mPTP opening in the presence or absence of GSNO, suggesting a crucial role for Cys-203 in mPTP activation. To determine whether mutation of C203S-CypD would alter mPTP in vivo, we injected a recombinant adenovirus encoding C203S-CypD or WT CypD into CypD(-/-) mice via tail vein. Mitochondria isolated from livers of CypD(-/-) mice or mice expressing C203S-CypD were resistant to Ca(2+)-induced swelling as compared with WT CypD-reconstituted mice. Our results indicate that the Cys-203 residue of CypD is necessary for redox stress-induced activation of mPTP.
Related JoVE Video
Reducing acid in dilute acid pretreatment and the impact on enzymatic saccharification.
J. Ind. Microbiol. Biotechnol.
PUBLISHED: 09-15-2011
Show Abstract
Hide Abstract
Dilute acid pretreatment is a leading pretreatment technology for biomass to ethanol conversion due to the comparatively low chemical cost and effective hemicellulose solubilization. The conventional dilute acid pretreatment processes use relatively large quantities of sulfuric acid and require alkali for pH adjustment afterwards. Significant amounts of sulfate salts are generated as by-products, which have to be properly treated before disposal. Wastewater treatment is an expensive, yet indispensable part of commercial level biomass-to-ethanol plants. Therefore, reducing acid use to the lowest level possible would be of great interest to the emerging biomass-to-ethanol industry. In this study, a dilute acid pretreatment process was developed for the pretreatment of corn stover. The pretreatment was conducted at lower acid levels than the conventional process reported in the literature while using longer residence times. The study indicates that a 50% reduction in acid consumption can be achieved without compromising pretreatment efficiency when the pretreatment time was extended from 1-5 min to 15-20 min. To avoid undesirable sugar degradation and inhibitor generation, temperatures should be controlled below 170°C. When the sulfuric acid-to-lignocellulosic biomass ratio was kept at 0.025 g acid/g dry biomass, a cellulose-to-glucose conversion of 72.7% can be achieved at an enzyme loading of 0.016 g/g corn stover. It was also found that acid loading based on total solids (g acid/g dry biomass) governs the pretreatment efficiency rather than the acid concentration (g acid/g pretreatment liquid). While the acid loading on lignocellulosic biomass may be achieved through various combinations of solids loading and acid concentration in the pretreatment step, this work shows that it is unlikely to reduce acid use without undermining pretreatment efficiency simply by increasing the solid content in pretreatment reactors, therefore acid loading on biomass is indicated to be the key factor in effective dilute acid pretreatment.
Related JoVE Video
Development of a rat model of bisphosphonate-related osteonecrosis of the jaw (BRONJ).
J Oral Implantol
PUBLISHED: 09-09-2011
Show Abstract
Hide Abstract
The purpose of this study was to develop a rat model predictive of bisphosphonate-related osteonecrosis of the jaw (BRONJ) after exodontias. Thirty female rats were randomized into 2 groups, control and experimental. The experimental group received 2 intravenous injections of zoledronate (20 ?g/kg). The mesial root of the right mandibular first molar was extracted. Rats were euthanized at 0, 4, and 8 weeks. Bone mineral density (BMD), collagen breakdown (pyridinium [PYD]), vascular regeneration (VEGF), and histology were examined. A trend toward higher PYD values was suggested in control vs experimental groups after wounding. Serum VEGF increased significantly after wounding for both control and experimental groups. After 8 weeks, VEGF continued to rise for the experimental group only. In the extraction socket area, BMD was significantly lower after wounding in control vs. zoledronate-treated rats. Histology sections from experimental groups showed bacteria and bone necrosis. Consistent findings of BRONJ features similar to those in humans were observed after zoledronate treatment.
Related JoVE Video
Household income and cardiovascular disease risks in U.S. children and young adults: analyses from NHANES 1999-2008.
Diabetes Care
PUBLISHED: 08-27-2011
Show Abstract
Hide Abstract
To assess the cardiovascular risk profile of youths across socioeconomic groups in the U.S.
Related JoVE Video
Out-of-hospital decision making and factors influencing the regional distribution of injured patients in a trauma system.
J Trauma
PUBLISHED: 08-06-2011
Show Abstract
Hide Abstract
The decision-making processes used for out-of-hospital trauma triage and hospital selection in regionalized trauma systems remain poorly understood. The objective of this study was to assess the process of field triage decision making in an established trauma system.
Related JoVE Video
Parkin is a lipid-responsive regulator of fat uptake in mice and mutant human cells.
J. Clin. Invest.
PUBLISHED: 07-20-2011
Show Abstract
Hide Abstract
It has long been hypothesized that abnormalities in lipid biology contribute to degenerative brain diseases. Consistent with this, emerging epidemiologic evidence links lipid alterations with Parkinson disease (PD), and disruption of lipid metabolism has been found to predispose to ?-synuclein toxicity. We therefore investigated whether Parkin, an E3 ubiquitin ligase found to be defective in patients with early onset PD, regulates systemic lipid metabolism. We perturbed lipid levels by exposing Parkin+/+ and Parkin-/- mice to a high-fat and -cholesterol diet (HFD). Parkin-/- mice resisted weight gain, steatohepatitis, and insulin resistance. In wild-type mice, the HFD markedly increased hepatic Parkin levels in parallel with lipid transport proteins, including CD36, Sr-B1, and FABP. These lipid transport proteins were not induced in Parkin-/- mice. The role of Parkin in fat uptake was confirmed by increased oleate accumulation in hepatocytes overexpressing Parkin and decreased uptake in Parkin-/- mouse embryonic fibroblasts and patient cells harboring complex heterozygous mutations in the Parkin-encoding gene PARK2. Parkin conferred this effect, in part, via ubiquitin-mediated stabilization of the lipid transporter CD36. Reconstitution of Parkin restored hepatic fat uptake and CD36 levels in Parkin-/- mice, and Parkin augmented fat accumulation during adipocyte differentiation. These results demonstrate that Parkin is regulated in a lipid-dependent manner and modulates systemic fat uptake via ubiquitin ligase-dependent effects. Whether this metabolic regulation contributes to premature Parkinsonism warrants investigation.
Related JoVE Video
Retrospective study of tracheostomy indications and perioperative complications on oral and maxillofacial surgery service.
J. Oral Maxillofac. Surg.
PUBLISHED: 06-21-2011
Show Abstract
Hide Abstract
Tracheostomy is an extremely common procedure performed by a variety of surgical specialties. The purpose of the present study was to review the intraoperative and perioperative management and complications, present our surgical technique, and discuss the role of our service in providing this care within a large community hospital setting.
Related JoVE Video
Transforming growth factor Beta2 is required for valve remodeling during heart development.
Dev. Dyn.
PUBLISHED: 06-20-2011
Show Abstract
Hide Abstract
Although the function of transforming growth factor beta2 (TGF?2) in epithelial mesenchymal transition (EMT) is well studied, its role in valve remodeling remains to be fully explored. Here, we used histological, morphometric, immunohistochemical and molecular approaches and showed that significant dysregulation of major extracellular matrix (ECM) components contributed to valve remodeling defects in Tgfb2(-/-) embryos. The data indicated that cushion mesenchymal cell differentiation was impaired in Tgfb2(-/-) embryos. Hyaluronan and cartilage link protein-1 (CRTL1) were increased in hyperplastic valves of Tgfb2(-/-) embryos, indicating increased expansion and diversification of cushion mesenchyme into the cartilage cell lineage during heart development. Finally, Western blot and immunohistochemistry analyses indicate that the activation of SMAD2/3 was decreased in Tgfb2(-/-) embryos during valve remodeling. Collectively, the data indicate that TGF?2 promotes valve remodeling and differentiation by inducing matrix organization and suppressing cushion mesenchyme differentiation into cartilage cell lineage during heart development.
Related JoVE Video
Of mice and convicts: origin of the Australian house mouse, Mus musculus.
PLoS ONE
PUBLISHED: 05-31-2011
Show Abstract
Hide Abstract
The house mouse, Mus musculus, is one of the most ubiquitous invasive species worldwide and in Australia is particularly common and widespread, but where it originally came from is still unknown. Here we investigated this origin through a phylogeographic analysis of mitochondrial DNA sequences (D-loop) comparing mouse populations from Australia with those from the likely regional source area in Western Europe. Our results agree with human historical associations, showing a strong link between Australia and the British Isles. This outcome is of intrinsic and applied interest and helps to validate the colonization history of mice as a proxy for human settlement history.
Related JoVE Video
Interactions between planar grafted neurofilament side-arms.
J Phys Chem B
PUBLISHED: 05-20-2011
Show Abstract
Hide Abstract
The side-arms of neurofilaments (NFs) have been proposed to be highly disordered, leading to an entropically and electrostatically based repulsion that modulates interfilament spacing. To characterize the behavior of two interacting polymer brushes in a system of this type, we performed molecular dynamics simulations of neurofilament brushes using a four bead reduced amino acid set coarse-grained model. In these simulations, we examined components of the neurofilament brush, NF-L, NF-M, and phosphorylated NF-H (NF-HP), individually. Each protein type was grafted to planar surfaces and simulations were performed for a range of separations of two apposed grafted surfaces. The calculated force-separation curves show the force increases as the reciprocal separation as predicted for polyelectrolyte brushes at high salt. All three systems can be overlapped on a single force-separation curve, which is not expected given the variation in amino acid sequence and charges on the polymers. Examination of structural properties shows scaling behavior in the average brush height, end-to-end distance, and the density interpenetration. Some of this scaling can be understood in terms of treating the NF proteins as effective polyelectrolytes, but some cannot suggesting a distinct polyampholyte behavior. Correlations are found between oppositely charged residues in opposite brushes. However, these correlations are weak in comparison to the strong correlations within each brush. In comparison with recent experimental data that observes condensed and expanded gel states, our results suggest that the condensed state structure involves significant interdigitation of the side-arms.
Related JoVE Video
Transmission and dose-response experiments for social animals: a reappraisal of the colonization biology of Campylobacter jejuni in chickens.
J R Soc Interface
PUBLISHED: 05-18-2011
Show Abstract
Hide Abstract
Dose-response experiments characterize the relationship between infectious agents and their hosts. These experiments are routinely used to estimate the minimum effective infectious dose for an infectious agent, which is most commonly characterized by the dose at which 50 per cent of challenged hosts become infected-the ID(50). In turn, the ID(50) is often used to compare between different agents and quantify the effect of treatment regimes. The statistical analysis of dose-response data typically makes the assumption that hosts within a given dose group are independent. For social animals, in particular avian species, hosts are routinely housed together in groups during experimental studies. For experiments with non-infectious agents, this poses no practical or theoretical problems. However, transmission of infectious agents between co-housed animals will modify the observed dose-response relationship with implications for the estimation of the ID(50) and the comparison between different agents and treatments. We derive a simple correction to the likelihood for standard dose-response models that allows us to estimate dose-response and transmission parameters simultaneously. We use this model to show that: transmission between co-housed animals reduces the apparent value of the ID(50) and increases the variability between replicates leading to a distinctive all-or-nothing response; in terms of the total number of animals used, individual housing is always the most efficient experimental design for ascertaining dose-response relationships; estimates of transmission from previously published experimental data for Campylobacter spp. in chickens suggest that considerable transmission occurred, greatly increasing the uncertainty in the estimates of dose-response parameters reported in the literature. Furthermore, we demonstrate that accounting for transmission in the analysis of dose-response data for Campylobacter spp. challenges our current understanding of the differing response of chickens with respect to host-age and in vivo passage of bacteria. Our findings suggest that the age-dependence of transmissibility between hosts-rather than their susceptibility to colonization-is the mechanism behind the lag-phase reported in commercial flocks, which are typically found to be Campylobacter free for the first 14-21 days of life.
Related JoVE Video
Developmental toxicity of two common corn pesticides to the endangered southern bell frog (Litoria raniformis).
Environ. Pollut.
PUBLISHED: 05-16-2011
Show Abstract
Hide Abstract
To examine the link between corn agriculture and the observed decline of the endangered southern bell frog (SBF), the effects of two corn crop pesticides on larval growth and development were investigated. Tadpoles were exposed to terbufos sulfone (10 ?g/L), a major breakdown product of the insecticide terbufos, and the herbicide atrazine (25 ?g/L) individually and as a mixture until the completion of metamorphosis. Atrazine did not interact synergistically with terbufos sulfone or result in significant effects on growth and development alone, although there was some indication of accelerated metamorphosis in the pilot study. Terbufos sulfone alone and as a mixture (terbufos/atrazine) significantly slowed larval development and ultimately delayed metamorphosis. The observed developmental effects from an environmentally relevant concentration of terbufos sulfone indicates a risk posed by this persistent degradation product to the endangered SBF, which breeds and develops in the rice bays adjacent to corn fields treated with pesticides.
Related JoVE Video
Vertical bone augmentation with simultaneous implant placement using particulate mineralized bone and mesenchymal stem cells: a preliminary study in rabbit.
J Oral Implantol
PUBLISHED: 05-13-2011
Show Abstract
Hide Abstract
This study aimed to assess vertical bone augmentation with simultaneous implant placement in rabbit tibiae using particulate mineralized bone/fibrin glue/mesenchymal stem cell. Bone marrow was aspirated from tibiae of five 10-week-old New Zealand White male rabbits. Right and left tibiae of each rabbit were prepared, and a 3-mm protruding implant from tibial bone was placed in each side. Particulate allogenic bone/fibrin glue/mesenchymal stem cell combination was placed around test implants and particulate bone graft/fibrin glue around controls. Two months postoperatively, the animals were euthanized, and sections were prepared for histological analysis. The mean amount of vertical bone length was higher in the experimental group than the control group (2.09 mm vs 1.03 mm; P < .05). New supracrestal trabecular bone formation was also significantly higher in the test group (28.5 ± 4.5% vs 4.3 ± 1.8%; P < .05). Mesenchymal stem cell/particulate allograft/fibrin glue appears to be a promising combination for vertical bone augmentation around simultaneously inserted implants in rabbit tibia.
Related JoVE Video
Autotransporters and Their Role in the Virulence of Burkholderia pseudomallei and Burkholderia mallei.
Front Microbiol
PUBLISHED: 04-28-2011
Show Abstract
Hide Abstract
Burkholderia pseudomallei and Burkholderia mallei are closely related Gram-negative bacteria responsible for the infectious diseases melioidosis and glanders, respectively. Autotransporters (ATs) comprise a large and diverse family of secreted and outer membrane proteins that includes virulence-associated invasins, adhesins, proteases, and actin-nucleating factors. The B. pseudomallei K96243 genome contains 11 predicted ATs, eight of which share homologs in the B. mallei ATCC 23344 genome. This review distils key findings from in silico, in vitro, and in vivo studies on the ATs of B. pseudomallei and B. mallei. To date, the best characterized of the predicted ATs of B. pseudomallei and B. mallei is BimA, a predicted trimeric AT mediating actin-based motility which varies in sequence and mode of action between Burkholderia species. Of the remaining eight predicted B. pseudomallei trimeric autotransporters, five of which are also present in B. mallei, two (BoaA and BoaB), have been implicated in bacterial adhesion to epithelial cells. Several predicted Burkholderia ATs are recognized by human humoral and cell-mediated immunity, indicating that they are expressed during infection and may be useful for diagnosis and vaccine-mediated protection. Further studies on the mode of secretion and functions of Burkholderia ATs will facilitate the rational design of control strategies.
Related JoVE Video
Treatment of chronic lead toxicity with succimer: a case series of 2 adults with retained lead shotgun fragments.
Am J Forensic Med Pathol
PUBLISHED: 04-23-2011
Show Abstract
Hide Abstract
Few recommendations exist for management of chronic lead toxicity in instances when the source of lead exposure cannot be removed.
Related JoVE Video
Genome sequences of Salmonella enterica serovar typhimurium, Choleraesuis, Dublin, and Gallinarum strains of well- defined virulence in food-producing animals.
J. Bacteriol.
PUBLISHED: 04-08-2011
Show Abstract
Hide Abstract
Salmonella enterica is an animal and zoonotic pathogen of worldwide importance and may be classified into serovars differing in virulence and host range. We sequenced and annotated the genomes of serovar Typhimurium, Choleraesuis, Dublin, and Gallinarum strains of defined virulence in each of three food-producing animal hosts. This provides valuable measures of intraserovar diversity and opportunities to formally link genotypes to phenotypes in target animals.
Related JoVE Video
Effect of polymer architecture and ionic aggregation on the scattering peak in model ionomers.
Phys. Rev. Lett.
PUBLISHED: 03-23-2011
Show Abstract
Hide Abstract
We perform molecular dynamics simulations of coarse-grained ionomer melts with two different architectures. Regularly spaced charged beads are placed either in the polymer backbone (ionenes) or pendant to it. The ionic aggregate structure is quantified as a function of the dielectric constant. The low wave vector ionomer scattering peak is present in all cases, but is significantly more intense for pendant ions, which form compact, discrete aggregates with liquidlike interaggregate order. This is in qualitative contrast to the ionenes, which form extended aggregates.
Related JoVE Video
Identification of motifs of Burkholderia pseudomallei BimA required for intracellular motility, actin binding, and actin polymerization.
J. Bacteriol.
PUBLISHED: 02-18-2011
Show Abstract
Hide Abstract
Actin-based motility of the melioidosis pathogen Burkholderia pseudomallei requires BimA (Burkholderia intracellular motility A). The mechanism by which BimA mediates actin assembly at the bacterial pole is ill-defined. Toward an understanding of the regions of B. pseudomallei BimA required for intracellular motility and the binding and polymerization of actin, we constructed plasmid-borne bimA variants and glutathione-S-transferase fusion proteins with in-frame deletions of specific motifs. A 13-amino-acid direct repeat and IP? proline-rich motif were dispensable for actin binding and assembly in vitro, and expression of the mutated proteins in a B. pseudomallei bimA mutant restored actin-based motility in J774.2 murine macrophage-like cells. However, two WASP homology 2 (WH2) domains were found to be required for actin binding, actin assembly, and plaque formation. A tract of five PDASX direct repeats influenced the polymerization of pyrene-actin monomers in vitro and was required for actin-based motility and intercellular spread, but not actin binding. None of the mutations impaired surface expression or polar targeting of BimA. The number of PDASX repeats varied in natural isolates from two to seven. Such repeats acted additively to promote pyrene-actin polymerization in vitro, with stepwise increases in the rate of polymerization as the number of repeats was increased. No differences in the efficiency of actin tail formation could be discerned between strains expressing BimA variants with two, five, or seven PDASX repeats. The data provide valuable new insights into the role of conserved and variable motifs of BimA in actin-based motility and intercellular spread of B. pseudomallei.
Related JoVE Video
Current trends in mesenchymal stem cell application in bone augmentation: a review of the literature.
J. Oral Maxillofac. Surg.
PUBLISHED: 02-14-2011
Show Abstract
Hide Abstract
The literature regarding mesenchymal stem cell (MSC)-based bone reconstruction techniques are sparse and no comprehensive review of current methods has been performed. The aim of this article was to provide a discussion of clinical and experimental reports of MSC application in the reconstruction of bony defects in live models.
Related JoVE Video
Can an arch bar replace a second lag screw in management of anterior mandibular fractures?
J. Oral Maxillofac. Surg.
PUBLISHED: 02-08-2011
Show Abstract
Hide Abstract
To evaluate the efficacy of using a single lag screw combined with an arch bar in the management of anterior mandibular fractures and to compare this method with the traditional application of 2 lag screws.
Related JoVE Video
Retrospective application of transposon-directed insertion site sequencing to a library of signature-tagged mini-Tn5Km2 mutants of Escherichia coli O157:H7 screened in cattle.
J. Bacteriol.
PUBLISHED: 01-28-2011
Show Abstract
Hide Abstract
Massively parallel sequencing of transposon-flanking regions assigned the genotype and fitness score to 91% of Escherichia coli O157:H7 mutants previously screened in cattle by signature-tagged mutagenesis (STM). The method obviates the limitations of STM and markedly extended the functional annotation of the prototype E. coli O157:H7 genome without further animal use.
Related JoVE Video
Burkholderia pseudomallei-induced cell fusion in U937 macrophages can be inhibited by monoclonal antibodies against host cell surface molecules.
Microbes Infect.
PUBLISHED: 01-19-2011
Show Abstract
Hide Abstract
Burkholderia pseudomallei induces the formation of multinucleated giant cells in cell monolayers. After infection of human macrophage-like U937 cells with B. pseudomallei, addition of monoclonal antibodies against integrin-associated protein (CD47), E-selectin (CD62E), a fusion regulatory protein (CD98), and E-cadherin (CD324) suppressed multinucleated giant cells in a concentration-dependent manner while monoclonal antibodies against other surface molecules did not inhibit fusion despite binding to the cell surface. Flow cytometric analysis showed increased expression of CD47 and CD98, but not CD62E and CD324, upon B. pseudomallei infection. Our data suggest the involvement of specific cellular factors in the process of B. pseudomallei-induced fusion.
Related JoVE Video
Coordinating medical civil military operations in Multinational Division-North.
Mil Med
PUBLISHED: 12-03-2010
Show Abstract
Hide Abstract
Medical civil military operations (MCMO) are part of military civil capacity-building efforts within the full spectrum of military operations, from war to military operations other than war. In 2008-2009 during Operation Iraqi Freedom, the Division Surgeons Section (DSS) of the 25th Infantry Division (25ID) and Multinational Division-North developed an innovative MCMO program in northern Iraq. The program centered on understanding and mapping key relationships, empowering brigade-level programs, and leveraging technology to identify and share best practices. The DSS mapped the critical relationships within and between the three entities affecting MCMO: the government of Iraq (GOI), Department of State (DOS), and the Department of Defense (DOD). A division MCMO working group was then created along with processes to facilitate MCMO project execution and program management. The structure and organization of the 25ID MCMO program lend themselves to other operational environments requiring synchronization of medical capacity-building efforts.
Related JoVE Video
Burkholderia pseudomallei proteins presented by monocyte-derived dendritic cells stimulate human memory T cells in vitro.
Infect. Immun.
PUBLISHED: 11-01-2010
Show Abstract
Hide Abstract
Melioidosis is a severe infectious disease caused by the saprophytic facultative intracellular pathogen Burkholderia pseudomallei. The disease is endemic in Southeast Asia and Northern Australia, and no effective vaccine exists. To describe human cell-mediated immune responses to B. pseudomallei and to identify candidate antigens for vaccine development, the ability of antigen-pulsed monocyte-derived dendritic cells (moDCs) to trigger autologous T-cell responses to B. pseudomallei and its products was tested. moDCs were prepared from healthy individuals exposed or not exposed to B. pseudomallei, based on serological evidence. These were pulsed with heat-killed B. pseudomallei or purified antigens, including ABC transporters (LolC, OppA, and PotF), Bsa type III secreted proteins (BipD and BopE), tandem repeat sequence-containing proteins (Rp1 and Rp2), flagellin, and heat shock proteins (Hsp60 and Hsp70), prior to being mixed with autologous T-cell populations. After pulsing of cells with either heat-killed B. pseudomallei, LolC, or Rp2, coculturing the antigen-pulsed moDCs with T cells elicited gamma interferon production from CD4(+) T cells from seropositive donors at levels greater than those for seronegative donors. These antigens also induced granzyme B (cytotoxic) responses from CD8(+) T cells. Activation of antigen-specific CD4(+) T cells required direct contact with moDCs and was therefore not dependent on soluble mediators. Rp peptide epitopes recognized by T cells in healthy individuals were identified. Our study provides valuable novel data on the induction of human cell-mediated immune responses to B. pseudomallei and its protein antigens that may be exploited in the rational development of vaccines to combat melioidosis.
Related JoVE Video
A low concentration of atrazine does not influence the acute toxicity of the insecticide terbufos or its breakdown products to Chironomus tepperi.
Ecotoxicology
PUBLISHED: 08-13-2010
Show Abstract
Hide Abstract
The acute toxicities of the insecticide terbufos and its major breakdown products individually, as binary mixtures, and in combination with the co-applied herbicide atrazine were evaluated using final instar larvae of the midge Chironomus tepperi. Terbufos, terbufos sulfoxide and terbufos sulfone were highly toxic to C. tepperi with mean 96-h EC50 values of 2.13, 3.64 and 2.59 ?g/l, respectively. No interaction was observed between atrazine (25 ?g/l) and terbufos or its breakdown products while the binary mixture of terbufos sulfoxide and terbufos sulfone exhibited additive toxicity. The high toxicities of terbufos and its environmentally persistent oxidation products suggest that contamination of aquatic systems with this insecticide pose a threat to aquatic organisms whether or not atrazine is also present.
Related JoVE Video
Splaying of aliphatic tails plays a central role in barrier crossing during liposome fusion.
J Phys Chem B
PUBLISHED: 08-13-2010
Show Abstract
Hide Abstract
The fusion between two lipid bilayers involves crossing a complicated energy landscape. The limiting barrier in the process appears to be between two closely opposed bilayers and the intermediate state where the outer leaflets are fused. We have performed molecular dynamics simulations to characterize the free energy barrier for the fusion of two liposomes and to examine the molecular details of barrier crossing. To capture the slow dynamics of fusion, a model using coarse-grained representations of lipids was used. The fusion between pairs of liposomes was simulated for four systems: DPPC, DOPC, a 3:1 mixture of DPPC/DPPE, and an asymmetric lipid tail system in which one tail of DPPC was reduced to half the length (ASTail). The weighted histogram method was used to compute the free energy as a function of separation distance. The relative barrier heights for these systems was found to be ASTail > DPPC > DPPC/DPPE > DOPC, in agreement with experimental observations. Further, the free energy curves for all four can be overlaid on a single curve by plotting the free energy versus the surface separation (differing only in the point of fusion). These simulations also confirm that the two main contributions to the free energy barrier are the removal of water between the vesicles and the deformation of the vesicle. The most prominent molecular detail of barrier crossing in all cases examined was the splaying of lipid tails, where initially a single splayed lipid formed a bridge between the two outer leaflets that promotes additional lipid mixing between the vesicles and eventually leads to fusion. The tail splay appears to be closely connected to the energetics of the process. For example, the high barrier for the ASTail is the result of a smaller distance between terminal methyl groups in the splayed molecule. The shortening of this distance requires the liposomes to be closer together, which significantly increases the cost of water removal and bilayer deformation. Before tail splay can initiate fusion, contact must occur between a tail end and the external water. In isolated vesicles, the contact fraction is correlated to the fusogenicity difference between DPPC and DOPC. Moreover, for planar bilayers, the contact fraction is much lower for DPPC, which is consistent with its lack of fusion in giant vesicles. The simulation results show the key roles of lipid tail dynamics in governing the fusion energy landscape.
Related JoVE Video
Reliability of quantitative real-time PCR for bacterial detection in cystic fibrosis airway specimens.
PLoS ONE
PUBLISHED: 08-10-2010
Show Abstract
Hide Abstract
The cystic fibrosis (CF) airway microbiome is complex; polymicrobial infections are common, and the presence of fastidious bacteria including anaerobes make culture-based diagnosis challenging. Quantitative real-time PCR (qPCR) offers a culture-independent method for bacterial quantification that may improve diagnosis of CF airway infections; however, the reliability of qPCR applied to CF airway specimens is unknown. We sought to determine the reliability of nine specific bacterial qPCR assays (total bacteria, three typical CF pathogens, and five anaerobes) applied to CF airway specimens. Airway and salivary specimens from clinically stable pediatric CF subjects were collected. Quantitative PCR assay repeatability was determined using triplicate reactions. Split-sample measurements were performed to measure variability introduced by DNA extraction. Results from qPCR were compared to standard microbial culture for Pseudomonas aeruginosa, Staphylococcus aureus, and Haemophilus influenzae, common pathogens in CF. We obtained 84 sputa, 47 oropharyngeal and 27 salivary specimens from 16 pediatric subjects with CF. Quantitative PCR detected bacterial DNA in over 97% of specimens. All qPCR assays were highly reproducible at quantities?10(2) rRNA gene copies/reaction with coefficient of variation less than 20% for over 99% of samples. There was also excellent agreement between samples processed in duplicate. Anaerobic bacteria were highly prevalent and were detected in mean quantities similar to that of typical CF pathogens. Compared to a composite gold standard, qPCR and culture had variable sensitivities for detection of P. aeruginosa, S. aureus and H. influenzae from CF airway samples. By reliably quantifying fastidious airway bacteria, qPCR may improve our understanding of polymicrobial CF lung infections, progression of lung disease and ultimately improve antimicrobial treatments.
Related JoVE Video
Actin-based motility of Burkholderia thailandensis requires a central acidic domain of BimA that recruits and activates the cellular Arp2/3 complex.
J. Bacteriol.
PUBLISHED: 08-06-2010
Show Abstract
Hide Abstract
Burkholderia species use BimA for intracellular actin-based motility. Uniquely, Burkholderia thailandensis BimA harbors a central and acidic (CA) domain. The CA domain was required for actin-based motility, binding to the cellular Arp2/3 complex, and Arp2/3-dependent polymerization of actin monomers. Our data reveal distinct strategies for actin-based motility among Burkholderia species.
Related JoVE Video
Solubility Limits of Cholesterol, Lanosterol, Ergosterol, Stigmasterol, and ?-Sitosterol in Electroformed Lipid Vesicles.
Soft Matter
PUBLISHED: 08-05-2010
Show Abstract
Hide Abstract
Here we use nuclear magnetic resonance to measure the solubility limit of several biologically relevant sterols in electroformed giant unilamellar vesicle membranes containing phosphatidylcholine (PC) lipids in ratios of 1:1:X DOPC:DPPC:sterol. We find solubility limits of cholesterol, lanosterol, ergosterol, stigmasterol, and ?-sitosterol to be 65-70%, ~35%, 30-35%, 20-25%, and ~40%, respectively. The low solubilities of stigmasterol and ?-sitosterol, which differ from cholesterol only in their alkyl tails, show that subtle differences in tail structure can strongly affect sterol solubility. Below the solubility limits, the fraction of sterol to PC-lipid in electroformed vesicles linearly reflects the fraction in the original stock solutions used in the electroformation process.
Related JoVE Video
Role of two-component sensory systems of Salmonella enterica serovar Dublin in the pathogenesis of systemic salmonellosis in cattle.
Microbiology (Reading, Engl.)
PUBLISHED: 07-23-2010
Show Abstract
Hide Abstract
Salmonella enterica serovar Dublin (S. Dublin) is associated with enteritis, typhoid and abortion in cattle. Infections are acquired by the oral route, and the bacteria transit through varied anatomical and cellular niches to elicit systemic disease. S. Dublin must therefore sense and respond to diverse extrinsic stimuli to control gene expression in a spatial and temporal manner. Two-component systems (TCSs) play key roles in such processes, and typically contain a membrane-associated sensor kinase (SK) that modifies a cognate response regulator. Analysis of the genome sequence of S. Dublin identified 31 conserved SK genes. Each SK gene was separately disrupted by lambda Red recombinase-mediated insertion of transposons harbouring unique sequence tags. Calves were challenged with a pool of the mutants together with control strains of defined virulence by the oral and intravenous routes. Quantification of tagged mutants in output pools derived from various tissues and cannulated lymphatic vessels allowed the assignment of spatial roles for each SK following oral inoculation or when the intestinal barrier was bypassed by intravenous delivery. Mutant phenotypes were also assigned in cultured intestinal epithelial cells. Mutants with insertions in barA, envZ, phoQ, ssrA or qseC were significantly negatively selected at all enteric and systemic sites sampled after oral dosing. Mutants lacking baeS, dpiB or citA were negatively selected at some but not all sites. After intravenous inoculation, only barA and phoQ mutants were significantly under-represented at systemic sites. The novel role of baeS in intestinal colonization was confirmed by oral co-infection studies, with a mutant exhibiting modest but significant attenuation at a number of enteric sites. This is the first systematic analysis of the role of all Salmonella TCSs in a highly relevant model of enteric fever. Spatial roles were assigned to eight S. Dublin SKs, but most were not essential for intestinal or systemic infection of the target host.
Related JoVE Video
6-hydroxydopamine-mediated release of norepinephrine increases faecal excretion of Salmonella enterica serovar Typhimurium in pigs.
Vet. Res.
PUBLISHED: 07-09-2010
Show Abstract
Hide Abstract
Salmonella enterica serovar Typhimurium is an animal and zoonotic pathogen of worldwide importance. In pigs, transport and social stress are associated with reactivation and spread of Salmonella Typhimurium infection. The stress-related catecholamine norepinephrine (NE) has been reported to activate growth and virulence factor expression in Salmonella; however the extent to which NE contributes to stress-associated salmonellosis is unclear. We studied the impact of releasing NE from endogenous stores during Salmonella Typhimurium infection of pigs by administration of 6-hydroxydopamine (6-OHDA), which selectively destroys noradrenergic nerve terminals. Treatment of pigs with 6-OHDA 7 or 16 days post-oral inoculation with Salmonella Typhimurium produced elevated plasma NE levels and transiently, but significantly, increased faecal excretion of the challenge strain. Oral administration of NE to Salmonella Typhimurium-infected pigs also transiently and significantly increased shedding; however pre-culture of the bacteria with NE did not alter the outcome of infection. Salmonella has been proposed to sense and respond to NE via a homologue of the adrenergic sensor kinase QseC. A DeltaqseC mutant of Salmonella Typhimurium was consistently excreted in lower numbers than the parent strain post-oral inoculation of pigs, though not significantly so. 6-OHDA treatment of pigs infected with the DeltaqseC mutant also increased faecal excretion of the mutant strain, albeit to a lesser extent than observed upon 6-OHDA treatment of pigs infected with the parent strain. Our data support the notion that stress-related catecholamines modulate the interaction of enteric bacterial pathogens with their hosts.
Related JoVE Video
Experience with the use of prebent plates for the reconstruction of mandibular defects.
Craniomaxillofac Trauma Reconstr
PUBLISHED: 06-24-2010
Show Abstract
Hide Abstract
Bending of large titanium plates for mandibular reconstruction is a tedious task. This is usually done by trial and error over an intraoperatively bent template. By means of rapid prototype technology, accurate three-dimensional models can be obtained. Using these models, it is possible to design, obtain, and adapt custom hardware for individual surgical cases. Reductions of operating room time when using this technology have been reported from 17% to 60%, with an average of 20%. This translates to reduction of cost and risks, improving the overall surgical outcome. The purpose of this article is to establish the indications and contraindication for the use three-dimensional models and prebent plates. We present our experience with five cases in which prebent reconstruction plates were used for mandibular reconstruction. No significant complications occurred, and satisfactory results were achieved in all cases. We found that the models required to obtain the hardware are extremely accurate, have multiple reported applications, and represent a valuable surgical tool in the planning and execution of reconstructive surgery.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.