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Find video protocols related to scientific articles indexed in Pubmed.
Analysis of Native Botulinum Neurotoxin Complexes in Clostridium botulinum Subtype A Strains by Immunoprecipitation.
Appl. Environ. Microbiol.
PUBLISHED: 11-02-2014
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Botulinum neurotoxins (BoNTs) naturally exist as a component of protein complexes containing nontoxic proteins. The nontoxic proteins impart stability of BoNTs in the gastrointestinal tract and during purification and handling. The two primary neurotoxin complexes (TCs) are: (a) TC1 consisting of BoNT, nontoxin-nonhemagglutinin (NTNH), hemagglutinins (HAs); and (b) TC2 consisting of BoNT, NTNH (and possibly OrfX proteins). In this study, BoNT/A subtypes A1, A2, A3 and A5 were examined for composition of their TCs in culture extracts using immunoprecipitation (IP). IP analyses showed that BoNT/A1 and/A5 form TC1s, while BoNT/A2, and/A3 form TC2s. A C. botulinum host strain expressing recombinant BoNT/A4 (normally present as a TC2) from an extrachromosomal plasmid formed a TC1 with complexing proteins from the host strain indicating that the HAs and NTNH encoded on the chromosome associated with the plasmid-encoded BoNT/A4. Strain NCTC 2916 (A1/silent B1) which carries both a ha silent bont/b cluster and an orfx bont/a1 cluster was also examined. IP analysis revealed that NCTC 2916 only formed a TC2 containing BoNT/A1 and its associated NTNH. No association between BoNT/A1 and the non-toxic proteins from the silent bont/b cluster was detected, although the HAs were expressed as determined by Western blot anaysis. Additionally, NTNH and HAs from the silent bont/b cluster did not form a complex in NCTC 2916.Stability of the two types of TC differed at various pHs and with addition of KCl and NaCl.TC1 complexes were more stable than TC2 complexes. Mouse serum stabilized TC2 while TC1 was unaffected.
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Use of High-Throughput Mass Spectrometry to Reduce False Positives in Protease uHTS Screens.
J Biomol Screen
PUBLISHED: 10-23-2014
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As a label-free technology, mass spectrometry (MS) enables assays to be generated that monitor the conversion of substrates with native sequences to products without the requirement for substrate modifications or indirect detection methods. Although traditional liquid chromatography (LC)-MS methods are relatively slow for a high-throughput screening (HTS) paradigm, with cycle times typically ?60?s per sample, the Agilent RapidFire High-Throughput Mass Spectrometry (HTMS) System, with a cycle time of 5-7?s per sample, enables rapid analysis of compound numbers compatible with HTS. By monitoring changes in mass directly, HTMS assays can be used as a triaging tool by eliminating large numbers of false positives resulting from fluorescent compound interference or from compounds interacting with hydrophobic fluorescent dyes appended to substrates. Herein, HTMS assays were developed for multiple protease programs, including cysteine, serine, and aspartyl proteases, and applied as a confirmatory assay. The confirmation rate for each protease assay averaged <30%, independent of the primary assay technology used (i.e., luminescent, fluorescent, and time-resolved fluorescent technologies). Importantly, >99% of compounds designed to inhibit the enzymes were confirmed by the corresponding HTMS assay. Hence, HTMS is an effective tool for removing detection-based false positives from ultrahigh-throughput screening, resulting in hit lists enriched in true actives for downstream dose response titrations and hit-to-lead efforts.
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Neuro- and social-cognitive clustering highlights distinct profiles in adults with anorexia nervosa.
Int J Eat Disord
PUBLISHED: 10-19-2014
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This study aimed to explore the neuro- and social-cognitive profile of a consecutive series of adult outpatients with anorexia nervosa (AN) when compared with widely available age and gender matched historical control data. The relationship between performance profiles, clinical characteristics, service utilization, and treatment adherence was also investigated.
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First Isolation and Characterization of a Minor Botulinum Neurotoxin Originating From a Dual Toxin Producing Clostridium botulinum Strain.
Appl. Environ. Microbiol.
PUBLISHED: 09-21-2014
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Clostridium botulinum subtype A4 neurotoxin (BoNT/A4) is naturally expressed in the dual-toxin producing strain C. botulinum 657Ba at 100 times lower titers compared to BoNT/B. In this study we describe for the first time purification of recombinant BoNT/A4 expressed in a nonsporulating and nontoxigenic C. botulinum expression host strain. The rBoNT/A4 co-purified with nontoxic toxin complex components provided in trans by the expression host, and was proteolytically cleaved to the active dichain form. Activity of the recombinant BoNT/A4 in mice and in human neuronal cells was about 1,000-fold lower than that of BoNT/A1, and the recombinant BoNT/A4 was effectively neutralized by Botulism Heptavalent Antitoxin. A previous report using recombinant truncated BoNT/A4 light chain (LC) expressed in E.coli has indicated reduced stability and activity of BoNT/A4 LC compared to BoNT/A1 LC, which was surmounted by introduction of a single amino acid substitution, I264R. In order to determine whether this mutation would also affect the holotoxin activity of BoNT/A4, a recombinant full-length rBoNT/A4 carrying this mutation as well as a second mutation predicted to increase solubility (L260F) was produced in the clostridial expression system. Comparative analyses of the in vitro, cellular, and in vivo activity of rBoNT/A4 and rBoNT/A4-L260F-I264R showed 1,000-fold lower activity than BoNT/A1 in both the mutated and non-mutated BoNT/A4. This indicates that these mutations do not alter the activity of BoNT/A4 holotoxin. In summary, a recombinant BoNT from a dual toxin producing strain was expressed and purified in an endogenous clostridial expression system allowing analysis of this toxin.
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Callose is integral to the development of permanent tetrads in the liverwort Sphaerocarpos.
Planta
PUBLISHED: 09-03-2014
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A striking feature of the liverwort Sphaerocarpos is that pairs of male and female spores remain united in permanent tetrads. To identify the nature of this phenomenon and to test the hypothesis that callose is involved, we examined spore wall development in Sphaerocarpos miche lii, with emphasis on the appearance, location and fate of callose vis-à-vis construction of the sculptoderm. All stages of sporogenesis were examined using differential interference contrast optics, and aniline blue fluorescence to locate callose. For precise localization, specimens were immunogold labeled with anti-callose antibody and observed in the transmission electron microscope. Callose plays a role in Sphaerocarpos spore wall development not described in any other plant, including other liverworts. A massive callose matrix forms outside of the sculptured sporocyte plasmalemma that predicts spore wall ornamentation. Consequently, layers of exine form across adjacent spores uniting them. Spore wall development occurs entirely within the callose and involves the production of six layers of prolamellae that give rise to single or stacked tripartite lamellae (TPL). Between spores, an anastomosing network of exine layers forms in lieu of intersporal septum development. As sporopollenin assembles on TPL, callose progressively disappears from the inside outward leaving layers of sporopollenin impregnated exine, the sculptoderm, overlying a thick fibrillar intine. This developmental mechanism provides a direct pathway from callose deposition to sculptured exine that does not involve the intermediary primexine found in pollen wall development. The resulting tetrad, encased in a single wall, provides a simple model for development of permanent dyads and tetrads in the earliest fossil plants.
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Beyond cigarettes per day. A genome-wide association study of the biomarker carbon monoxide.
Ann Am Thorac Soc
PUBLISHED: 07-30-2014
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The CHRNA5-CHRNA3-CHRNB4 locus is associated with self-reported smoking behavior and also harbors the strongest genetic associations with chronic obstructive pulmonary disease (COPD) and lung cancer. Because the associations with lung disease remain after adjustment for self-reported smoking behaviors, it has been asserted that CHRNA5-CHRNA3-CHRNB4 variants increase COPD and lung cancer susceptibility independently of their effects on smoking.
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Characterization of THB1, a Chlamydomonas reinhardtii truncated hemoglobin: linkage to nitrogen metabolism and identification of lysine as the distal heme ligand.
Biochemistry
PUBLISHED: 07-09-2014
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The nuclear genome of the model organism Chlamydomonas reinhardtii contains genes for a dozen hemoglobins of the truncated lineage. Of those, THB1 is known to be expressed, but the product and its function have not yet been characterized. We present mutagenesis, optical, and nuclear magnetic resonance data for the recombinant protein and show that at pH near neutral in the absence of added ligand, THB1 coordinates the heme iron with the canonical proximal histidine and a distal lysine. In the cyanomet state, THB1 is structurally similar to other known truncated hemoglobins, particularly the heme domain of Chlamydomonas eugametos LI637, a light-induced chloroplastic hemoglobin. Recombinant THB1 is capable of binding nitric oxide (NO(•)) in either the ferric or ferrous state and has efficient NO(•) dioxygenase activity. By using different C. reinhardtii strains and growth conditions, we demonstrate that the expression of THB1 is under the control of the NIT2 regulatory gene and that the hemoglobin is linked to the nitrogen assimilation pathway.
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Introduction of a covalent histidine-heme linkage in a hemoglobin: A promising tool for heme protein engineering.
J. Inorg. Biochem.
PUBLISHED: 07-04-2014
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The hemoglobins of the cyanobacteria Synechococcus and Synechocystis (GlbNs) are capable of spontaneous and irreversible attachment of the b heme to the protein matrix. The reaction, which saturates the heme 2-vinyl by addition of a histidine residue, is reproduced in vitro by preparing the recombinant apoprotein, adding ferric heme, and reducing the iron to the ferrous state. Spontaneous covalent attachment of the heme is potentially useful for protein engineering purposes. Thus, to explore whether the histidine-heme linkage can serve in such applications, we attempted to introduce it in a test protein. We selected as our target the heme domain of Chlamydomonas eugametos LI637 (CtrHb), a eukaryotic globin that exhibits less than 50% sequence identity with the cyanobacterial GlbNs. We chose two positions, 75 in the FG corner and 111 in the H helix, to situate a histidine near a vinyl group. We characterized the proteins with gel electrophoresis, absorbance spectroscopy, and NMR analysis. Both T111H and L75H CtrHbs reacted upon reduction of the ferric starting material containing cyanide as the distal ligand to the iron. With L75H CtrHb, nearly complete (>90%) crosslinking was observed to the 4-vinyl as expected from the X-ray structure of wild-type CtrHb. Reaction of T111H CtrHb also occurred at the 4-vinyl, in a 60% yield indicating a preference for the flipped heme orientation in the starting material. The work suggests that the His-heme modification will be applicable to the design of proteins with a non-dissociable heme group.
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Widespread sequence variations in VAMP1 across vertebrates suggest a potential selective pressure from botulinum neurotoxins.
PLoS Pathog.
PUBLISHED: 07-01-2014
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Botulinum neurotoxins (BoNT/A-G), the most potent toxins known, act by cleaving three SNARE proteins required for synaptic vesicle exocytosis. Previous studies on BoNTs have generally utilized the major SNARE homologues expressed in brain (VAMP2, syntaxin 1, and SNAP-25). However, BoNTs target peripheral motor neurons and cause death by paralyzing respiratory muscles such as the diaphragm. Here we report that VAMP1, but not VAMP2, is the SNARE homologue predominantly expressed in adult rodent diaphragm motor nerve terminals and in differentiated human motor neurons. In contrast to the highly conserved VAMP2, BoNT-resistant variations in VAMP1 are widespread across vertebrates. In particular, we identified a polymorphism at position 48 of VAMP1 in rats, which renders VAMP1 either resistant (I48) or sensitive (M48) to BoNT/D. Taking advantage of this finding, we showed that rat diaphragms with I48 in VAMP1 are insensitive to BoNT/D compared to rat diaphragms with M48 in VAMP1. This unique intra-species comparison establishes VAMP1 as a physiological toxin target in diaphragm motor nerve terminals, and demonstrates that the resistance of VAMP1 to BoNTs can underlie the insensitivity of a species to members of BoNTs. Consistently, human VAMP1 contains I48, which may explain why humans are insensitive to BoNT/D. Finally, we report that residue 48 of VAMP1 varies frequently between M and I across seventeen closely related primate species, suggesting a potential selective pressure from members of BoNTs for resistance in vertebrates.
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A Cohort Mortality Study of Workers in a Second Soup Manufacturing Plant.
Arch Environ Occup Health
PUBLISHED: 06-28-2014
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ABSTRACT We previously reported on mortality among workers in a Baltimore soup plant. Increased mortality was observed for cancers of the floor of the mouth, recto-sigmoid colon/rectum/anus, epilepsy, and chronic nephritis. Here we report on mortality on a second soup plant in the same locality. Excess mortality was similarly recorded for cancers of the tonsils/oropharynx, recto-sigmoid colon/rectum/anus, lung and myelofibrosis. Excess risk from cardiovascular, cerebrovascular, kidney and infectious diseases was also observed. These two studies are important because firstly, to our knowledge they are the only reports of mortality in this occupational group in spite of their having a potential for exposure to hazardous carcinogenic agents. Secondly, there is no information on any exposure assessment in this industry. These two reports will draw attention to the need to conduct more detailed exposure and mortality investigations in this little-studied group.
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Genome Sequence of the Neurotoxigenic Clostridium butyricum Strain 5521.
Genome Announc
PUBLISHED: 06-28-2014
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Clostridium strains from six phylogenetic groups, C. botulinum groups I to IV, C. baratii, and C. butyricum, display the capacity to produce botulinum neurotoxin. Here, we present the genome sequence of a C. butyricum isolate, the neurotoxigenic strain 5521, which encodes the type E botulinum neurotoxin.
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Characterization of SEMA3A-encoded semaphorin as a naturally occurring Kv4.3 protein inhibitor and its contribution to Brugada syndrome.
Circ. Res.
PUBLISHED: 06-24-2014
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Semaphorin 3A (SEMA3A)-encoded semaphorin is a chemorepellent that disrupts neural patterning in the nervous and cardiac systems. In addition, SEMA3A has an amino acid motif that is analogous to hanatoxin, an inhibitor of voltage-gated K(+) channels. SEMA3A-knockout mice exhibit an abnormal ECG pattern and are prone to ventricular arrhythmias and sudden cardiac death.
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Time-dependent estimates of recurrence and survival in colon cancer: clinical decision support system tool development for adjuvant therapy and oncological outcome assessment.
Am Surg
PUBLISHED: 06-03-2014
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Unanswered questions remain in determining which high-risk node-negative colon cancer (CC) cohorts benefit from adjuvant therapy and how it may differ in an equal access population. Machine-learned Bayesian Belief Networks (ml-BBNs) accurately estimate outcomes in CC, providing clinicians with Clinical Decision Support System (CDSS) tools to facilitate treatment planning. We evaluated ml-BBNs ability to estimate survival and recurrence in CC. We performed a retrospective analysis of registry data of patients with CC to train-test-crossvalidate ml-BBNs using the Department of Defense Automated Central Tumor Registry (January 1993 to December 2004). Cases with events or follow-up that passed quality control were stratified into 1-, 2-, 3-, and 5-year survival cohorts. ml-BBNs were trained using machine-learning algorithms and k-fold crossvalidation and receiver operating characteristic curve analysis used for validation. BBNs were comprised of 5301 patients and areas under the curve ranged from 0.85 to 0.90. Positive predictive values for recurrence and mortality ranged from 78 to 84 per cent and negative predictive values from 74 to 90 per cent by survival cohort. In the 12-month model alone, 1,132,462,080 unique rule sets allow physicians to predict individual recurrence/mortality estimates. Patients with Stage II (N0M0) CC benefit from chemotherapy at different rates. At one year, all patients older than 73 years of age with T2-4 tumors and abnormal carcinoembryonic antigen levels benefited, whereas at five years, all had relative reduction in mortality with the largest benefit amongst elderly, highest T-stage patients. ml-BBN can readily predict which high-risk patients benefit from adjuvant therapy. CDSS tools yield individualized, clinically relevant estimates of outcomes to assist clinicians in treatment planning.
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Novel Operative Anoscope for Ferguson Hemorrhoidectomy: A Feasibility Study and Comparative Cohort Analysis.
Surg Innov
PUBLISHED: 06-01-2014
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Background. Operative hemorrhoidectomy can result in pain and altered continence from excessive excision of anoderm or surrounding tissue.. We assessed a novel low-profile slotted anoscope to determine if the device would promote safe dissection, lessen trauma, and reduce operative times for hemorrhoidectomy. Methods. Patients requiring hemorrhoidectomy (June 2008 - January 2010) underwent a prospective phase-2 trial evaluating a new operating anoscope (CAD, Ethicon Endosurgery, Cincinnati, OH). Demographics and perioperative end points including bleeding, pain, fecal incontinence, stenosis, and symptom recurrence were analyzed at 4 weeks, 3 months, 6 months, and 1 year postoperatively. We compared these to patients undergoing hemorrhoidectomy (February 2010 - November 2012) with a traditional Hill-Ferguson anoscope (THF). Results. 40 patients (CAD, 20 vs THF, 20) were included. Presenting symptoms were similar, whereas mean duration of symptoms was longer for CAD (41.2 ± 8.4 vs 27 ± 9.5 months; P < .05). Estimated blood loss was lower for CAD [8.3 mL (range = 2-40 mL) vs 11.3 mL THF (range = 5-35 mL; P = .87)]. Mean operative times were lower for the CAD than the THF group (15.6 ± 3.4 vs 26.1 ± 4.1 minutes; P < .05). Visual analog pain scores were non-significantly increased in the THF group at 4 weeks (P = .23). At 3 months, 6 months, and 1 year, there was no difference in continence. Conclusion. The CAD anoscope reduced operative times for modified Ferguson (closed) hemorrhoidectomy when compared with traditional retractors. There was no difference in incontinence or pain between groups.
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Multiple domains of tetanus toxin direct entry into primary neurons.
Traffic
PUBLISHED: 05-15-2014
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Tetanus toxin elicits spastic paralysis by cleaving VAMP-2 to inhibit neurotransmitter release in inhibitory neurons of the central nervous system. As the retrograde transport of tetanus neurotoxin (TeNT) from endosomes has been described, the initial steps that define how TeNT initiates trafficking to the retrograde system are undefined. This study examines TeNT entry into primary cultured cortical neurons by total internal reflection fluorescence (TIRF) microscopy. The initial association of TeNT with the plasma membrane was dependent upon ganglioside binding, but segregated from synaptophysin1 (Syp1), a synaptic vesicle (SV) protein. TeNT entry was unaffected by membrane depolarization and independent of SV cycling, whereas entry of the receptor-binding domain of TeNT (HCR/T) was stimulated by membrane depolarization and inhibited by blocking SV cycling. Measurement of the incidence of colocalization showed that TeNT segregated from Syp1, whereas HCR/T colocalized with Syp1. These studies show that while the HCR defines the initial association of TeNT with the cell membrane, regions outside the HCR define how TeNT enters neurons independent of SV cycling. This provides a basis for the unique entry of botulinum toxin and tetanus toxin into neurons.
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Two adjustment strategies for imputation across genotyping arrays.
Hum. Hered.
PUBLISHED: 04-30-2014
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Genotype imputation is a powerful approach in genome-wide association studies (GWAS) because it can provide higher resolution for associated regions and facilitate meta-analysis. However, bias can exist if different genotyping arrays are used and are unbalanced for case versus control subjects. The intersection imputation strategy [imputation based on single nucleotide polymorphisms (SNPs) available on all arrays] is a valid strategy that eliminates the bias caused by unbalanced genotyping, but achieved at the expense of reduced statistical power. In order to improve power in this situation, we introduce two new strategies: the replacement strategy based on the imputation quality score (IQS) ?0.9 and the correction strategy. The IQS is a score that we have previously introduced based on Cohen's kappa of rater agreement. The replacement strategy with IQS ?0.9 is a hybrid approach that utilizes measured genotypes for SNPs available on one or more of all arrays whenever the SNP has a high imputation quality (defined by IQS ?0.9). The correction strategy combines measured genotypes as well as imputed and corrected genotype dosages for SNPs available on one or more of all arrays. The correction strategy yields a valid statistical test, while the replacement strategy with IQS ?0.9 eliminates most spurious associations. Both strategies maintain statistical power.
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The impact of an acute care surgery team on general surgery residency.
Am. J. Surg.
PUBLISHED: 04-14-2014
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Acute care surgical teams (ACSTs) have limited data in residency. We sought to determine the impact of an ACST on the depth and breadth of general surgery resident training.
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Clostridium botulinum strains producing BoNT/F4 or BoNT/F5.
Appl. Environ. Microbiol.
PUBLISHED: 03-14-2014
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Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.
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Predicting 90-day mortality after bariatric surgery: an independent, external validation of the OS-MRS prognostic risk score.
Surg Obes Relat Dis
PUBLISHED: 03-03-2014
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The Obesity Surgery Mortality Risk Score (OS-MRS) was developed using data from 1995 to 2004; it has yet to be validated for more recent patients in integrated delivery system settings. The objective of this study was to validate the OS-MRS using data from electronic health records in a distributed data network.
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Anal squamous cell carcinoma: an evolution in disease and management.
World J. Gastroenterol.
PUBLISHED: 03-03-2014
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Anal cancer represents less than 1% of all new cancers diagnosed annually in the United States. Yet, despite the relative paucity of cases, the incidence of anal cancer has seen a steady about 2% rise each year over the last decade. As such, all healthcare providers need to be cognizant of the evaluation and treatment of anal squamous cell carcinoma. While chemoradiation remains the mainstay of therapy for most patients with anal cancer, surgery may still be required in recurrent, recalcitrant and palliative disease. In this manuscript, we will explore the diagnosis and management of squamous cell carcinoma of the anus.
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Routine colonic endoscopic evaluation following resolution of acute diverticulitis: is it necessary?
World J. Gastroenterol.
PUBLISHED: 02-20-2014
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Diverticular disease incidence is increasing up to 65% by age 85 in industrialized nations, low fiber diets, and in younger and obese patients. Twenty-five percent of patients with diverticulosis will develop acute diverticulitis. This imposes a significant burden on healthcare systems, resulting in greater than 300000 admissions per year with an estimated annual cost of $3 billion USD. Abdominal computed tomography (CT) is the diagnostic study of choice, with a sensitivity and specificity greater than 95%. Unfortunately, similar CT findings can be present in colonic neoplasia, especially when perforated or inflamed. This prompted professional societies such as the American Society of Colon Rectal Surgeons to recommend patients undergo routine colonoscopy after an episode of acute diverticulitis to rule out malignancy. Yet, the data supporting routine colonoscopy after acute diverticulitis is sparse and based small cohort studies utilizing outdated technology. While any patient with an indication for a colonoscopy should undergo appropriate endoscopic evaluation, in the era of widespread use of high-resolution computed tomography, routine colonic endoscopic evaluation following resolution of acute uncomplicated diverticulitis poses additional costs, comes with inherent risks, and may require further study. In this manuscript, we review the current data related to this recommendation.
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The impact of pregnancy on surgical Crohn disease: an analysis of the Nationwide Inpatient Sample.
J. Surg. Res.
PUBLISHED: 02-13-2014
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The impact of pregnancy on the course of Crohn disease is largely unknown. Retrospective surveys have suggested a variable effect, but there are limited population-based clinical data. We hypothesized pregnant women with Crohn disease will have similar rates of surgical disease as a nonpregnant Crohn disease cohort.
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Prophylactic antibiotics for hemorrhoidectomy: are they really needed?
Dis. Colon Rectum
PUBLISHED: 02-11-2014
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Hemorrhoidectomy is considered by many to be a contaminated operation that requires antibiotic prophylaxis to lower the incidence of surgical site infection. In reality, little evidence exists to either support or refute the use of antibiotic prophylaxis in this setting.
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The impact of age on colorectal cancer incidence, treatment, and outcomes in an equal-access health care system.
Dis. Colon Rectum
PUBLISHED: 02-11-2014
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Inferior outcomes in younger patients with colorectal cancer may be associated with multiple factors, including tumor biology, delayed diagnosis, disparities such as access to care, and/or treatment differences.
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Visual evaluation of the larynx and hypopharynx during esophagogastroduodenoscopy: a safety and feasibility study.
Surg Endosc
PUBLISHED: 02-04-2014
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The larynx and hypopharynx are common sites for head and neck cancer, which shares many risk factors with upper digestive tract disease. Patient survival with malignancies depends on stage at the time of diagnosis. Endoscopic screening of the hypopharynx is neither routinely performed in clinical practice nor has it been evaluated in a formal study.
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Entry of a recombinant, full-length, atoxic tetanus neurotoxin into Neuro-2a cells.
Infect. Immun.
PUBLISHED: 01-31-2014
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Tetanus neurotoxin (TeNT) and botulinum neurotoxin (BoNT) are clostridial neurotoxins (CNTs) responsible for the paralytic diseases tetanus and botulism, respectively. CNTs are AB toxins with an N-terminal zinc-metalloprotease light chain that is linked by a disulfide bond to a C-terminal heavy chain that includes a translocation domain and a receptor-binding domain (HCR). Current models predict that the HCR defines how CNTs enter and traffic in neurons. Recent studies implicate that domains outside the HCR contribute to CNT trafficking in neurons. In the current study, a recombinant, full-length TeNT derivative, TeNT(RY), was engineered to analyze TeNT cell entry. TeNT(RY) was atoxic in a mouse challenge model. Using Neuro-2a cells, a mouse neuroblastoma cell line, TeNT HCR (HCR/T) and TeNT(RY) were found to bind gangliosides with similar affinities and specificities, consistent with the HCR domain containing receptor binding function. Temporal studies showed that HCR/T and TeNT(RY) entered Neuro-2a cells slower than the HCR of BoNT/A (HCR/A), transferrin, and cholera toxin B. Intracellular localization showed that neither HCR/T nor TeNT(RY) localized with HCR/A or synaptic vesicle protein 2, the protein receptor for HCR/A. HCR/T and TeNT(RY) exhibited only partial intracellular colocalization, indicating that regions outside the HCR contribute to the intracellular TeNT trafficking. TeNT may require this complex functional entry organization to target neurons in the central nervous system.
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Reactive oxygen species mediate pollen tube rupture to release sperm for fertilization in Arabidopsis.
Nat Commun
PUBLISHED: 01-24-2014
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In flowering plants, sperm are transported inside pollen tubes to the female gametophyte for fertilization. The female gametophyte induces rupture of the penetrating pollen tube, resulting in sperm release and rendering them available for fertilization. Here we utilize the Arabidopsis FERONIA (FER) receptor kinase mutants, whose female gametophytes fail to induce pollen tube rupture, to decipher the molecular mechanism of this critical male-female interactive step. We show that FER controls the production of high levels of reactive oxygen species at the entrance to the female gametophyte to induce pollen tube rupture and sperm release. Pollen tube growth assays in vitro and in the pistil demonstrate that hydroxyl free radicals are likely the most reactive oxygen molecules, and they induce pollen tube rupture in a Ca(2+)-dependent process involving Ca(2+) channel activation. Our results provide evidence for a RHO GTPase-based signalling mechanism to mediate sperm release for fertilization in plants.
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Crohn's disease and pregnancy: the impact of perianal disease on delivery methods and complications.
Dis. Colon Rectum
PUBLISHED: 01-10-2014
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The optimal delivery method in patients with Crohn's disease is unknown, and there is no large-scale evidence on which to base decisions.
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Analysis of gene expression in induced pluripotent stem cell-derived human neurons exposed to botulinum neurotoxin a subtype 1 and a type a atoxic derivative.
PLoS ONE
PUBLISHED: 01-01-2014
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Botulinum neurotoxin type A1 (BoNT/A1) is a potent protein toxin responsible for the potentially fatal human illness botulism. Notwithstanding, the long-lasting flaccid muscle paralysis caused by BoNT/A has led to its utility as a powerful and versatile bio-pharmaceutical. The flaccid paralysis is due to specific cleavage of neuronal SNAREs by BoNTs. However, actions of BoNTs on intoxicated neurons besides the cleavage of SNAREs have not been studied in detail. In this study we investigated by microarray analysis the effects of BoNT/A and a catalytically inactive derivative (BoNT/A ad) on the transcriptome of human induced pluripotent stem cell (hiPSC)-derived neurons at 2 days and 2 weeks after exposure. While there were only minor changes in expression levels at 2 days post exposure, at 2 weeks post exposure 492 genes were differentially expressed more than 2-fold in BoNT/A1-exposed cells when compared to non-exposed populations, and 682 genes were differentially expressed in BoNT/A ad-exposed cells. The vast majority of genes were similarly regulated in BoNT/A1 and BoNT/A ad-exposed neurons, and the few genes differentially regulated between BoNT/A1 and BoNT/A ad-exposed neurons were differentially expressed less than 3.5 fold. These data indicate a similar response of neurons to BoNT/A1 and BoNT/A ad exposure. The most highly regulated genes in cells exposed to either BoNT/A1 or BoNT/A ad are involved in neurite outgrowth and calcium channel sensitization.
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Future directions for the early detection of colorectal cancer recurrence.
J Cancer
PUBLISHED: 01-01-2014
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Surgical resection remains a mainstay of treatment and is highly effective for localized colorectal cancer. However, ~30-40% of patients develop recurrence following surgery and 40-50% of recurrences are apparent within the first few years after initial surgical resection. Several variables factor into the ultimate outcome of these patients, including the extent of disease, tumor biology, and patient co-morbidities. Additionally, the time from initial treatment to the development of recurrence is strongly associated with overall survival, particularly in patients who recur within one year of their surgical resection. Current post-resection surveillance strategies involve physical examination, laboratory, endoscopic and imaging studies utilizing various high and low-intensity protocols. Ultimately, the goal is to detect recurrence as early as possible, and ideally in the asymptomatic localized phase, to allow initiation of treatment that may still result in cure. While current strategies have been effective, several efforts are evolving to improve our ability to identify recurrent disease at its earliest phase. Our aim with this article is to briefly review the options available and, more importantly, examine emerging and future options to assist in the early detection of colon and rectal cancer recurrence.
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Early detection of colorectal cancer recurrence in patients undergoing surgery with curative intent: current status and challenges.
J Cancer
PUBLISHED: 01-01-2014
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Despite advances in neoadjuvant and adjuvant therapy, attention to proper surgical technique, and improved pathological staging for both the primary and metastatic lesions, almost half of all colorectal cancer patients will develop recurrent disease. More concerning, this includes ~25% of patients with theoretically curable node-negative, non-metastatic Stage I and II disease. Given the annual incidence of colorectal cancer, approximately 150,000 new patients are candidates each year for follow-up surveillance. When combined with the greater population already enrolled in a surveillance protocol, this translates to a tremendous number of patients at risk for recurrence. It is therefore imperative that strategies aim for detection of recurrence as early as possible to allow initiation of treatment that may still result in cure. Yet, controversy exists regarding the optimal surveillance strategy (high-intensity vs. traditional), ideal testing regimen, and overall effectiveness. While benefits may involve earlier detection of recurrence, psychological welfare improvement, and greater overall survival, this must be weighed against the potential disadvantages including more invasive tests, higher rates of reoperation, and increased costs. In this review, we will examine the current options available and challenges surrounding colorectal cancer surveillance and early detection of recurrence.
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Atoxic derivative of botulinum neurotoxin A as a prototype molecular vehicle for targeted delivery to the neuronal cytoplasm.
PLoS ONE
PUBLISHED: 01-01-2014
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We have previously described genetic constructs and expression systems that enable facile production of recombinant derivatives of botulinum neurotoxins (BoNTs) that retain the structural and trafficking properties of wt BoNTs. In this report we describe the properties of one such derivative, BoNT/A ad, which was rendered atoxic by introducing two amino acid mutations to the light chain (LC) of wt BoNT/A, and which is being developed as a molecular vehicle for delivering drugs to the neuronal cytoplasm. The neuronal binding, internalization, and intracellular trafficking of BoNT/A ad in primary hippocampal cultures was evaluated using three complimentary techniques: flow cytometry, immunohistochemistry, and Western blotting. Neuronal binding of BoNT ad was significantly increased when neurons were incubated in depolarizing medium. Flow cytometry demonstrated that BoNT/A ad internalized into neurons but not glia. After 24 hours, the majority of the neuron-bound BoNT/A ad became internalized, as determined by its resistance to pronase E-induced proteolytic degradation of proteins associated with the plasma membrane of intact cells. Significant amounts of the atoxic LC accumulated in a Triton X-100-extractable fraction of the neurons, and persisted as such for at least 11 days with no evidence of degradation. Immunocytochemical analysis demonstrated that the LC of BoNT/A ad was translocated to the neuronal cytoplasm after uptake and was specifically targeted to SNARE proteins. The atoxic LC consistently co-localized with synaptic markers SNAP-25 and VAMP-2, but was rarely co-localized with markers for early or late endosomes. These data demonstrate that BoNT/A ad mimics the trafficking properties of wt BoNT/A, confirming that our platform for designing and expressing BoNT derivatives provides an accessible system for elucidating the molecular details of BoNT trafficking, and can potentially be used to address multiple medical and biodefense needs.
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Future directions for monitoring treatment response in colorectal cancer.
J Cancer
PUBLISHED: 01-01-2014
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Treatment of advanced colon and rectal cancer has significantly evolved with the introduction of neoadjuvant chemoradiation therapy so much that, along with more effective chemotherapy regimens, surgery has been considered unnecessary among some institutions for select patients. The tumor response to these treatments has also improved and ultimately has been shown to have a direct effect on prognosis. Yet, the best way to monitor that response, whether clinically, radiologically, or with laboratory findings, remains controversial. The authors' aim is to briefly review the options available and, more importantly, examine emerging and future options to assist in monitoring treatment response in cases of locally advanced rectal cancer and metastatic colon cancer.
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Current approaches and challenges for monitoring treatment response in colon and rectal cancer.
J Cancer
PUBLISHED: 01-01-2014
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With the advent of multidisciplinary and multimodality approaches to the management of colorectal cancer patients, there is an increasing need to define how we monitor response to novel therapies in these patients. Several factors ranging from the type of therapy used to the intrinsic biology of the tumor play a role in tumor response. All of these can aid in determining the ideal course of treatment, and may fluctuate over time, pending down-staging or progression of disease. Therefore, monitoring how disease responds to therapy requires standardization in order to ultimately optimize patient outcomes. Unfortunately, how best to do this remains a topic of debate among oncologists, pathologists, and colorectal surgeons. There may not be one single best approach. The goal of the present article is to shed some light on current approaches and challenges to monitoring treatment response for colorectal cancer.
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Outcomes among chronically ill adults in a medical home prototype.
Am J Manag Care
PUBLISHED: 12-06-2013
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Objectives: To compare quality, utilization, and cost outcomes for patients with selected chronic illnesses at a patient-centered medical home (PCMH) prototype site with outcomes for patients with the same chronic illnesses at 19 nonintervention control sites. Study Design: Nonequivalent pretest-posttest control group design. Methods: PCMH redesign results were investigated for patients with preexisting diabetes, hypertension, and/or coronary heart disease. Data from automated databases were collected for eligible enrollees in an integrated healthcare delivery system. Multivariable regression models tested for adjusted differences between PCMH patients and controls during the baseline and follow-up periods. Dependent measures under study included clinical processes and, outcomes, monthly healthcare utilization, and costs. Results: Compared with controls over 2 years, patients at the PCMH prototype clinic had slightly better clinical outcome control in coronary heart disease (2.20 mg/dL lower mean low-density lipoprotein cholesterol; P <.001). PCMH patients changed their patterns of primary care utilization, as reflected by 86% more secure electronic message contacts (P <.001), 10% more telephone contacts (P = .003), and 6% fewer in-person primary care visits (P <.001). PCMH patients had 21% fewer ambulatory care-sensitive hospitalizations (P <.001) and 7% fewer total inpatient admissions (P = .002) than controls. During the 2-year redesign, we observed 17% lower inpatient costs (P <.001) and 7% lower total healthcare costs (P <.001) among patients at the PCMH prototype clinic. Conclusions: A clinic-level population-based PCMH redesign can decrease downstream utilization and reduce total healthcare costs in a subpopulation of patients with common chronic illnesses.
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Secular trends in colon and rectal cancer relative survival.
J. Natl. Cancer Inst.
PUBLISHED: 10-30-2013
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Treatment options for colorectal cancer (CRC) have improved substantially over the past 25 years. Measuring the impact of these improvements on survival outcomes is challenging, however, against the background of overall survival gains from advancements in the prevention, screening, and treatment of other conditions. Relative survival is a metric that accounts for these concurrent changes, allowing assessment of changes in CRC survival. We describe stage- and location-specific trends in relative survival after CRC diagnosis.
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Improvements in symptoms following neuronavigated repetitive transcranial magnetic stimulation (rTMS) in severe and enduring anorexia nervosa: findings from two case studies.
Eur Eat Disord Rev
PUBLISHED: 10-25-2013
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Advances in the treatment of anorexia nervosa (AN) are most likely to arise from targeted, brain-directed treatments, such as repetitive transcranial magnetic stimulation (rTMS). We describe findings from two individuals with treatment-resistant AN who received 19-20 sessions of neuronavigated, high frequency rTMS, applied to the left dorsolateral prefrontal cortex.
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Targeting botulinum a cellular toxicity: a prodrug approach.
J. Med. Chem.
PUBLISHED: 10-15-2013
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The botulinum neurotoxin light chain (LC) protease has become an important therapeutic target for postexposure treatment of botulism. Hydroxamic acid based small molecules have proven to be potent inhibitors of LC/A with nanomolar Ki values, yet they lack cellular activity conceivably due to low membrane permeability. To overcome this potential liability, we investigated two prodrug strategies, 1,4,2-dioxazole and carbamate, based on our 1-adamantylacetohydroxamic acid scaffold. The 1,4,2-dioxazole prodrug did not demonstrate cellular activity, however, carbamates exhibited cellular potency with the most active compound displaying an EC50 value of 20 ?M. Cellular trafficking studies were conducted using a "fluorescently silent" prodrug that remained in this state until cellular uptake was complete, which allowed for visualization of the drugs release inside neuronal cells. In sum, this research sets the stage for future studies leveraging the specific targeting and delivery of these prodrugs, as well as other antibotulinum agents, into neuronal cells.
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Synthesis/biological evaluation of hydroxamic acids and their prodrugs as inhibitors for Botulinum neurotoxin A light chain.
Bioorg. Med. Chem.
PUBLISHED: 10-11-2013
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Botulinum neurotoxin A (BoNT/A) is the most potent toxin known. Unfortunately, it is also a potential bioweapon in terrorism, which is without an approved therapeutic treatment once cellular intoxication takes place. Previously, we reported how hydroxamic acid prodrug carbamates increased cellular uptake, which translated to successful inhibition of this neurotoxin. Building upon this research, we detail BoNT/A protease molecular modeling studies accompanied by the construction of small library of hydroxamic acids based on 2,4-dichlorocinnamic hydroxamic acid scaffold and their carbamate prodrug derivatization along with the evaluation of these molecules in both enzymatic and cellular models.
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Laparoscopy utilization and outcomes for appendicitis in small children.
J. Pediatr. Surg.
PUBLISHED: 10-01-2013
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To examine the trends in laparoscopic appendectomy (LA) utilization and outcomes for children 5 years or younger.
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The globins of cyanobacteria and algae.
Adv. Microb. Physiol.
PUBLISHED: 09-24-2013
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Approximately, 20 years ago, a haemoglobin gene was identified within the genome of the cyanobacterium Nostoc commune. Haemoglobins have now been confirmed in multiple species of photosynthetic microbes beyond N. commune, and the diversity of these proteins has recently come under increased scrutiny. This chapter summarizes the state of knowledge concerning the phylogeny, physiology and chemistry of globins in cyanobacteria and green algae. Sequence information is by far the best developed and the most rapidly expanding aspect of the field. Structural and ligand-binding properties have been described for just a few proteins. Physiological data are available for even fewer. Although activities such as nitric oxide dioxygenation and oxygen scavenging are strong candidates for cellular function, dedicated studies will be required to complete the story on this intriguing and ancient group of proteins.
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DSM-5 cannabis use disorder: A phenotypic and genomic perspective.
Drug Alcohol Depend
PUBLISHED: 08-29-2013
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We explore the factor structure of DSM-5 cannabis use disorders, examine its prevalence across European- and African-American respondents as well as its genetic underpinnings, utilizing data from a genome-wide study of single nucleotide polymorphisms (SNPs). We also estimate the heritability of DSM-5 cannabis use disorders explained by these common SNPs.
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The ZZ Domain of Dystrophin in DMD: Making Sense of Missense Mutations.
Hum. Mutat.
PUBLISHED: 08-15-2013
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Duchenne muscular dystrophy (DMD) is associated with the loss of dystrophin, which plays an important role in myofiber integrity via interactions with ?-dystroglycan and other members of the transmembrane dystrophin-associated protein complex. The ZZ domain, a cysteine-rich zinc-finger domain near the dystrophin C-terminus, is implicated in forming a stable interaction between dystrophin and ?-dystroglycan, but the mechanism of pathogenesis of ZZ missense mutations has remained unclear because not all such mutations have been shown to alter ?-dystroglycan binding in previous experimental systems. We engineered three ZZ mutations (p.Cys3313Phe, p.Asp3335His, and p.Cys3340Tyr) into a short construct similar to the Dp71 dystrophin isoform for in vitro and in vivo studies and delineated their effect on protein expression, folding properties, and binding partners. Our results demonstrate two distinct pathogenic mechanisms for ZZ missense mutations. The cysteine mutations result in diminished or absent subsarcolemmal expression because of protein instability, likely due to misfolding. In contrast, the aspartic acid mutation disrupts binding with ?-dystroglycan despite an almost normal expression at the membrane, confirming a role for the ZZ domain in ?-dystroglycan binding but surprisingly demonstrating that such binding is not required for subsarcolemmal localization of dystrophin, even in the absence of actin binding domains.
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Rapid induction of the triterpenoid pathway in Arabidopsis thaliana mesophyll protoplasts.
Biotechnol. Lett.
PUBLISHED: 08-06-2013
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Purpose of work: The purpose of this study was to determine if Arabidopsis protoplast transfection could be scaled up, from the commonly used cell-based studies, to be used in triterpenoid production assays as an in planta alternative/complement to other expression systems. Enzyme activities are often identified using heterologous expression systems such as yeast cells. These systems, however, may be incompatible for expressing enzymes involved in specialized (secondary) metabolism. Previous reports with long-term in planta expression systems show that the activity of the triterpenoid pathway can be enhanced by expressing enzymes catalyzing initial steps in the pathway. Here we show that triterpenoid production can also be enhanced in Arabidopsis mesophyll protoplasts after transfection. This system is designed to quantify changes in productivity of a plant metabolic pathway within 48 h and, as proof of concept, we show a significantly increased production of a triterpenoid by transiently expressing squalene synthase 1 (SQS1) from 0.5 pg/protoplast in mock-transfected protoplasts to 2.7 pg/protoplast in constitutively expressing SQS1 protoplasts.
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Characterization of botulinum neurotoxin A subtypes 1 through 5 by investigation of activities in mice, in neuronal cell cultures, and in vitro.
Infect. Immun.
PUBLISHED: 08-05-2013
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Botulinum neurotoxins (BoNTs) are synthesized by Clostridium botulinum and exist as seven immunologically distinct serotypes designated A through G. For most serotypes, several subtypes have now been described based on nominal differences in the amino acid sequences. BoNT/A1 is the most well-characterized subtype of the BoNT/A serotype, and many of its properties, including its potency, its prevalence as a food poison, and its utility as a pharmaceutical, have been thoroughly studied. In contrast, much remains unknown of the other BoNT/A subtypes. In this study, BoNT/A subtype 1 (BoNT/A1) to BoNT/A5 were characterized utilizing a mouse bioassay, an in vitro cleavage assay, and several neuronal cell-based assays. The data indicate that BoNT/A1 to -5 have distinct in vitro and in vivo toxicological properties and that, unlike those for BoNT/A1, the neuronal and mouse results for BoNT/A2 to -5 do not correlate with their enzymatic activity. These results indicate that BoNT/A1 to -5 have distinct characteristics, which are of importance for a greater understanding of botulism and for pharmaceutical applications.
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Using hyper as a molecular probe to visualize hydrogen peroxide in living plant cells: a method with virtually unlimited potential in plant biology.
Meth. Enzymol.
PUBLISHED: 07-09-2013
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Reactive oxygen species (ROS) are highly reactive reduced oxygen molecules that play a myriad of roles in animal and plant cells. In plant cells, the production of ROS occurs as a result of aerobic metabolism during respiration and photosynthesis. Therefore mitochondria, chloroplasts, and peroxisomes constitute an important source of ROS. However, they can be produced in response to many physiological stimuli such as pathogen attack, hormone signaling, abiotic stresses, or during cell wall organization and plant morphogenesis. Monitoring ROS in plant cells has been limited to biochemical assays and use of fluorescent probes, however, the irreversible oxidation of the fluorescent dyes make it impossible to visualize dynamic changes of ROS. Hyper is a recently developed live cell probe for H2O2 and consists of a circularly permutated YFP (cpYFP) inserted into the regulatory domain of the Escherichia coli hydrogen peroxide (H2O2) sensor OxyR rendering it a H2O2 specific ratiometric, and therefore quantitative probe. Herein, we describe a protocol for using Hyper as a dynamic probe for H2O2 in Arabidopsis with virtually unlimited potential to detect H2O2 throughout the plant and under a broad range of developmental and environmental conditions.
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Spreading a medical home redesign: effects on emergency department use and hospital admissions.
Ann Fam Med
PUBLISHED: 05-22-2013
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The patient-centered medical home (PCMH) is being rapidly deployed in many settings to strengthen US primary care, improve quality, and control costs; however, evidence supporting this transformation is still lacking. We describe the Group Health experience in attempting to replicate the effects on health care use seen in a PCMH prototype clinic via a systemwide spread using Lean as the change strategy.
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Surgical technique: Tscherne-Johnson extensile approach for tibial plateau fractures.
Clin. Orthop. Relat. Res.
PUBLISHED: 05-15-2013
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The standard approach to lateral tibial plateau fractures involves elevation of the iliotibial band (IT) and anterior tibialis origin in continuity from Gerdys tubercle and metaphyseal flare. We describe an alternative approach to increase lateral plateau joint exposure and maintain iliotibial band insertion to Gerdys tubercle.
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The MOSAIC study - comparison of the Maudsley Model of Treatment for Adults with Anorexia Nervosa (MANTRA) with Specialist Supportive Clinical Management (SSCM) in outpatients with anorexia nervosa or eating disorder not otherwise specified, anorexia nerv
Trials
PUBLISHED: 05-14-2013
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Anorexia nervosa (AN) is a biologically based serious mental disorder with high levels of mortality and disability, physical and psychological morbidity and impaired quality of life. AN is one of the leading causes of disease burden in terms of years of life lost through death or disability in young women. Psychotherapeutic interventions are the treatment of choice for AN, but the results of psychotherapy depend critically on the stage of the illness. The treatment response in adults with a chronic form of the illness is poor and drop-out from treatment is high. Despite the seriousness of the disorder the evidence-base for psychological treatment of adults with AN is extremely limited and there is no leading treatment. There is therefore an urgent need to develop more effective treatments for adults with AN. The aim of the Maudsley Outpatient Study of Treatments for Anorexia Nervosa and Related Conditions (MOSAIC) is to evaluate the efficacy and cost effectiveness of two outpatient treatments for adults with AN, Specialist Supportive Clinical Management (SSCM) and the Maudsley Model of Treatment for Adults with Anorexia Nervosa (MANTRA).
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Enhancing the protective immune response against botulism.
Infect. Immun.
PUBLISHED: 05-13-2013
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The need for a vaccine against botulism has increased since the discontinuation of the pentavalent (ABCDE) botulinum toxoid vaccine by the Centers for Disease Control and Prevention. The botulinum toxins (BoNTs) are the primary virulence factors and vaccine components against botulism. BoNTs comprise three domains which are involved in catalysis (LC), translocation (HCT), and host receptor binding (HCR). Recombinant HCR subunits have been used to develop the next generation of BoNT vaccines. Using structural studies and the known entry properties of BoNT/A, an HCR subunit vaccine against BoNT/A that contained the point mutation W1266A within the ganglioside binding pocket was designed. HCR/A(W1266A) did not enter primary neurons, and the crystal structure of HCR/A(W1266A) was virtually identical to that of wild-type HCR/A. Using a mouse model, experiments were performed using a high-dose vaccine and a low-dose vaccine. At a high vaccine dose, HCR/A and HCR/A(W1266A) elicited a protective immune response to BoNT/A challenge. At the low-dose vaccination, HCR/A(W1266A) was a more protective vaccine than HCR/A. ?-HCR IgG titers correlated with protection from BoNT challenge, although titers to block HCR/A entry were greater in serum in HCR/A-vaccinated mice than in HCR/A(W1266A)-vaccinated mice. This study shows that removal of receptor binding capacity enhances potency of the subunit HCR vaccine. Vaccines that lack receptor binding capacity have the added property of limited off-target toxicity.
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Comparison of the catalytic properties of the botulinum neurotoxin subtypes A1 and A5.
Biochim. Biophys. Acta
PUBLISHED: 05-07-2013
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Clostridium botulinum neurotoxins (BoNTs) cause the life-threatening disease botulism through the inhibition of neurotransmitter release by cleaving essential SNARE proteins. There are seven serologically distinctive types of BoNTs and many subtypes within a serotype have been identified. BoNT/A5 is a recently discovered subtype of type A botulinum neurotoxin which possesses a very high degree of sequence similarity and identity to the well-studied A1 subtype. In the present study, we examined the endopeptidase activity of these two BoNT/A subtypes and our results revealed significant differences in substrate binding and cleavage efficiency between subtype A5 and A1. Distinctive hydrolysis efficiency was observed between the two toxins during cleavage of the native substrate SNAP-25 versus a shortened peptide mimic. N-terminal truncation studies demonstrated that a key region of the SNAP-25, including the amino acid residues at 151 through 154 located in the remote binding region of the substrate, contributed to the differential catalytic properties between A1 and A5. Elevated binding affinity of the peptide substrate resulted from including these important residues and enhanced BoNT/A5s hydrolysis efficiency. In addition, mutations of these amino acid residues affect the proteolytic performance of the two toxins in different ways. This study provides a better understanding of the biological activity of these toxins, their performance characteristics in the Endopep-MS assay to detect BoNT in clinical samples and foods, and is useful for the development of peptide substrates.
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Inter-observer agreement according to malaria parasite density.
Malar. J.
PUBLISHED: 05-03-2013
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Recent developments in diagnostic techniques for malaria, particularly DNA probes and sero-immunology, have raised questions as to how these techniques might be used to facilitate malaria diagnosis at the most peripheral levels of the primary health care system. At present, malaria diagnosis is based on the standard microscopic examination of blood films in most field epidemiologic studies and is likely to remain so in the immediate future in Africa. The objective of this study was to assess inter-observer agreement for the examination of Giemsa-stained slides for Plasmodium falciparum parasites.
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Dabigatran bleed risk with closed head injuries: are we prepared?
J. Neurosurg.
PUBLISHED: 05-01-2013
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The direct thrombin inhibitor dabigatran has recently been approved in the US as an alternative to warfarin. The lack of guidelines, protocols, and an established specific antidote to reverse the anticoagulation effect of dabigatran potentially increases the rates of morbidity and mortality in patients with closed head injury (CHI). Confronted with this new problem, the authors reviewed their initial clinical experience.
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Endoscopy and polyps-diagnostic and therapeutic advances in management.
World J. Gastroenterol.
PUBLISHED: 04-27-2013
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Despite multiple efforts aimed at early detection through screening, colon cancer remains the third leading cause of cancer-related deaths in the United States, with an estimated 51000 deaths during 2013 alone. The goal remains to identify and remove benign neoplastic polyps prior to becoming invasive cancers. Polypoid lesions of the colon vary widely from hyperplastic, hamartomatous and inflammatory to neoplastic adenomatous growths. Although these lesions are all benign, they are common, with up to one-quarter of patients over 60 years old will develop pre-malignant adenomatous polyps. Colonoscopy is the most effective screening tool to detect polyps and colon cancer, although several studies have demonstrated missed polyp rates from 6%-29%, largely due to variations in polyp size. This number can be as high as 40%, even with advanced (> 1 cm) adenomas. Other factors including sub-optimal bowel preparation, experience of the endoscopist, and patient anatomical variations all affect the detection rate. Additional challenges in decision-making exist when dealing with more advanced, and typically larger, polyps that have traditionally required formal resection. In this brief review, we will explore the recent advances in polyp detection and therapeutic options.
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Monitoring foreign gene incorporation into the plastome of Chlamydomonas reinhardtii by multiplex qPCR.
Photosyn. Res.
PUBLISHED: 04-23-2013
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The genetic material of the Chlamydomonas reinhardtii chloroplast can be easily manipulated and creation of transgenic plastomes is of interest for both photosynthetic research and for biofuel and biomass production. Because multiple copies of the chloroplast genome are present, it is important to understand whether, following the introduction of a foreign gene, the resulting transgenic plastome is homoplasmic or heteroplasmic. By quantitative PCR together with a simple DNA extraction procedure and a series of DNA oligonucleotides the following protocol will determine the extent of foreign gene incorporation into a host chloroplast plastome. This approach is used to follow the degree of heteroplasmy following biolistic transformation of several transgenic strains. The approach used is quick, simple to set up, and gives an accurate quantitation of foreign genes within of the chloroplast plastome. Possible future uses of the technique are discussed.
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Massively parallel characterization of restriction endonucleases.
Nucleic Acids Res.
PUBLISHED: 04-19-2013
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Restriction endonucleases are highly specific in recognizing the particular DNA sequence they act on. However, their activity is affected by sequence context, enzyme concentration and buffer composition. Changes in these factors may lead to either ineffective cleavage at the cognate restriction site or relaxed specificity allowing cleavage of degenerate star sites. Additionally, uncharacterized restriction endonucleases and engineered variants present novel activities. Traditionally, restriction endonuclease activity is assayed on simple substrates such as plasmids and synthesized oligonucleotides. We present and use high-throughput Illumina sequencing-based strategies to assay the sequence specificity and flanking sequence preference of restriction endonucleases. The techniques use fragmented DNA from sequenced genomes to quantify restriction endonuclease cleavage on a complex genomic DNA substrate in a single reaction. By mapping millions of restriction site-flanking reads back to the Escherichia coli and Drosophila melanogaster genomes we were able to quantitatively characterize the cognate and star site activity of EcoRI and MfeI and demonstrate genome-wide decreases in star activity with engineered high-fidelity variants EcoRI-HF and MfeI-HF, as well as quantify the influence on MfeI cleavage conferred by flanking nucleotides. The methods presented are readily applicable to all type II restriction endonucleases that cleave both strands of double-stranded DNA.
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An evaluation of colonoscopy surveillance guidelines: are we actually adhering to the guidelines?
Am. J. Surg.
PUBLISHED: 04-18-2013
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National guidelines put forth by the American Cancer Society, the US Multi-Society Task Force on Colorectal Cancer, and the American College of Gastroenterology provide recommendations regarding colorectal cancer screening and follow-up surveillance. Practice patterns may differ from these guidelines. This study analyzes the concordance between a tertiary equal access system and national guidelines for colorectal cancer and polyp surveillance.
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Outcome comparison following colorectal cancer surgery in an equal access system.
J. Surg. Res.
PUBLISHED: 04-11-2013
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Previous reports suggest outcome differences following surgery for colorectal cancer (CRC) based on specialist and volume-related metrics. We sought to compare community and tertiary centers in an equal access system.
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A microscale neuron and Schwann cell coculture model for increasing detection sensitivity of botulinum neurotoxin type A.
Toxicol. Sci.
PUBLISHED: 04-05-2013
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Botulinum neurotoxin (BoNT) is a potent and specific biomolecule that is both implicated as a potential threat in bioterrorism and used in therapeutics. Highly sensitive and robust assays that measure BoNT activity are needed to manage outbreak or controlled distribution of BoNT. Current in vivo and in vitro assays have limitations, including high costs and variability for mouse bioassays, extensive preparations for primary and stem cell-derived neurons, and inherent low sensitivity for cell lines. Sensitivity of cell lines can be increased by direct differentiation and with their physiological relevance (compared with cell-free strategies) and robustness (compared with primary cell strategies); adopting cell lines is an attractive alternative to in vivo assays. Here, we present two distinct strategies that improved sensitivity of a cell line to BoNT serotype A (BoNT/A) without direct differentiation. We developed a cell-based BoNT assay using microscale culture and coculture of neuronal and Schwann cell lines, NG108-15 and S16, respectively, to improve both sensitivity and physiological relevance. Results showed that NG108-15 and S16 coculture decreased EC50 from 12.5 to 0.8ng/µl (p < 0.001) in macroscale and from 2.6 to 1.1ng/µl (p = 0.006) in microscale. In addition, NG108-15 monoculture at microscale decreased EC50 from 12.5 to 2.6ng/µl (p < 0.001) compared with macroscale. Finally, controlling the spatial arrangement of microscale coculture revealed that S16-derived soluble factors can increase sensitivity. Thus, our study demonstrates two distinct strategies for increasing the sensitivity of a cell line to BoNT using coculture and microscale culture, thereby advancing assay technology for BoNT detection.
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Pilonidal disease in a military population: how far have we really come?
Am. J. Surg.
PUBLISHED: 04-01-2013
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Pilonidal disease (PD) has a long connection with military personnel, even nicknamed "jeep disease" during World War II. The aim of this study was to identify factors associated with recurrence and complications after surgery in a military population.
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The impact of Model for End-Stage Liver Disease-Na in predicting morbidity and mortality following elective colon cancer surgery irrespective of underlying liver disease.
Am. J. Surg.
PUBLISHED: 03-24-2013
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The Model for End-Stage Liver Disease Sodium Model (MELD-Na) is a validated scoring system that uses bilirubin, international normalized ratio, serum creatinine, and sodium to predict mortality in cirrhotic patients awaiting liver transplantation. The aim of this study was to identify the utility of MELD-Na to predict patient outcomes, with and without liver disease, after elective colon cancer surgery.
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Genome Sequence of the Group III Clostridium botulinum Strain Eklund-C.
Genome Announc
PUBLISHED: 03-22-2013
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The neurotoxins produced by Clostridium botulinum strains are among the worlds most potent toxins and are the causative agents of paralytic botulism. Here, we present the draft genome sequence of the group III C. botulinum strain Eklund-C, including a pseudolysogen-like bacteriophage that harbors the type C neurotoxin operon.
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Biotechnology of non-Saccharomyces yeasts-the basidiomycetes.
Appl. Microbiol. Biotechnol.
PUBLISHED: 03-08-2013
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Yeasts are the major producer of biotechnology products worldwide, exceeding production in capacity and economic revenues of other groups of industrial microorganisms. Yeasts have wide-ranging fundamental and industrial importance in scientific, food, medical, and agricultural disciplines (Fig. 1). Saccharomyces is the most important genus of yeast from fundamental and applied perspectives and has been expansively studied. Non-Saccharomyces yeasts (non-conventional yeasts) including members of the Ascomycetes and Basidiomycetes also have substantial current utility and potential applicability in biotechnology. In an earlier mini-review, "Biotechnology of non-Saccharomyces yeasts-the ascomycetes" (Johnson Appl Microb Biotechnol 97: 503-517, 2013), the extensive biotechnological utility and potential of ascomycetous yeasts are described. Ascomycetous yeasts are particularly important in food and ethanol formation, production of single-cell protein, feeds and fodder, heterologous production of proteins and enzymes, and as model and fundamental organisms for the delineation of genes and their function in mammalian and human metabolism and disease processes. In contrast, the roles of basidiomycetous yeasts in biotechnology have mainly been evaluated only in the past few decades and compared to the ascomycetous yeasts and currently have limited industrial utility. From a biotechnology perspective, the basidiomycetous yeasts are known mainly for the production of enzymes used in pharmaceutical and chemical synthesis, for production of certain classes of primary and secondary metabolites such as terpenoids and carotenoids, for aerobic catabolism of complex carbon sources, and for bioremediation of environmental pollutants and xenotoxicants. Notwithstanding, the basidiomycetous yeasts appear to have considerable potential in biotechnology owing to their catabolic utilities, formation of enzymes acting on recalcitrant substrates, and through the production of unique primary and secondary metabolites. This and the earlier mini-review (Johnson Appl Microb Biotechnol 97:503-517, 2013) were motivated during the preparation and publication of the landmark three-volume set of "The yeasts: a taxonomic study, 5th edition" (Kurtzman et al. 2011a, b).
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Association of toxin-producing Clostridium botulinum with the macroalga Cladophora in the Great Lakes.
Environ. Sci. Technol.
PUBLISHED: 03-04-2013
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Avian botulism, a paralytic disease of birds, often occurs on a yearly cycle and is increasingly becoming more common in the Great Lakes. Outbreaks are caused by bird ingestion of neurotoxins produced by Clostridium botulinum, a spore-forming, gram-positive, anaerobe. The nuisance, macrophytic, green alga Cladophora (Chlorophyta; mostly Cladophora glomerata L.) is a potential habitat for the growth of C. botulinum. A high incidence of botulism in shoreline birds at Sleeping Bear Dunes National Lakeshore (SLBE) in Lake Michigan coincides with increasingly massive accumulations of Cladophora in nearshore waters. In this study, free-floating algal mats were collected from SLBE and other shorelines of the Great Lakes between June and October 2011. The abundance of C. botulinum in algal mats was quantified and the type of botulism neurotoxin (bont) genes associated with this organism were determined by using most-probable-number PCR (MPN-PCR) and five distinct bont gene-specific primers (A, B, C, E, and F). The MPN-PCR results showed that 16 of 22 (73%) algal mats from the SLBE and 23 of 31(74%) algal mats from other shorelines of the Great Lakes contained the bont type E (bont/E) gene. C. botulinum was present up to 15000 MPN per gram dried algae based on gene copies of bont/E. In addition, genes for bont/A and bont/B, which are commonly associated with human diseases, were detected in a few algal samples. Moreover, C. botulinum was present as vegetative cells rather than as dormant spores in Cladophora mats. Mouse toxin assays done using supernatants from enrichment of Cladophora containing high densities of C. botulinum (>1000 MPN/g dried algae) showed that Cladophora-borne C. botulinum were toxin-producing species (BoNT/E). Our results indicate that Cladophora provides a habitat for C. botulinum, warranting additional studies to better understand the relationship between this bacterium and the alga, and how this interaction potentially contributes to botulism outbreaks in birds.
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Surgical outcomes of total knee replacement according to diabetes status and glycemic control, 2001 to 2009.
J Bone Joint Surg Am
PUBLISHED: 03-01-2013
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Poor glycemic control in patients with diabetes may be associated with adverse surgical outcomes. We sought to determine the association of diabetes status and preoperative glycemic control with several surgical outcomes, including revision arthroplasty and deep infection.
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Genomic patterns of introgression in rainbow and westslope cutthroat trout illuminated by overlapping paired-end RAD sequencing.
Mol. Ecol.
PUBLISHED: 02-21-2013
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Rapid and inexpensive methods for genomewide single nucleotide polymorphism (SNP) discovery and genotyping are urgently needed for population management and conservation. In hybridized populations, genomic techniques that can identify and genotype thousands of species-diagnostic markers would allow precise estimates of population- and individual-level admixture as well as identification of super invasive alleles, which show elevated rates of introgression above the genomewide background (likely due to natural selection). Techniques like restriction-site-associated DNA (RAD) sequencing can discover and genotype large numbers of SNPs, but they have been limited by the length of continuous sequence data they produce with Illumina short-read sequencing. We present a novel approach, overlapping paired-end RAD sequencing, to generate RAD contigs of >300-400 bp. These contigs provide sufficient flanking sequence for design of high-throughput SNP genotyping arrays and strict filtering to identify duplicate paralogous loci. We applied this approach in five populations of native westslope cutthroat trout that previously showed varying (low) levels of admixture from introduced rainbow trout (RBT). We produced 77 141 RAD contigs and used these data to filter and genotype 3180 previously identified species-diagnostic SNP loci. Our population-level and individual-level estimates of admixture were generally consistent with previous microsatellite-based estimates from the same individuals. However, we observed slightly lower admixture estimates from genomewide markers, which might result from natural selection against certain genome regions, different genomic locations for microsatellites vs. RAD-derived SNPs and/or sampling error from the small number of microsatellite loci (n = 7). We also identified candidate adaptive super invasive alleles from RBT that had excessively high admixture proportions in hybridized cutthroat trout populations.
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Examining the relevance of the physicians clinical assessment and the reliance on computed tomography in diagnosing acute appendicitis.
Am. J. Surg.
PUBLISHED: 02-04-2013
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The aim of this study was to examine the relevance of clinical assessment in diagnosing appendicitis in the current medical environment, in which routine use of computed tomography (CT) has become the norm.
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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.