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.
Joint entropy for space and spatial frequency domains estimated from psychometric functions of achromatic discrimination.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
We used psychometric functions to estimate the joint entropy for space discrimination and spatial frequency discrimination. Space discrimination was taken as discrimination of spatial extent. Seven subjects were tested. Gábor functions comprising unidimensionalsinusoidal gratings (0.4, 2, and 10 cpd) and bidimensionalGaussian envelopes (1°) were used as reference stimuli. The experiment comprised the comparison between reference and test stimulithat differed in grating's spatial frequency or envelope's standard deviation. We tested 21 different envelope's standard deviations around the reference standard deviation to study spatial extent discrimination and 19 different grating's spatial frequencies around the reference spatial frequency to study spatial frequency discrimination. Two series of psychometric functions were obtained for 2%, 5%, 10%, and 100% stimulus contrast. The psychometric function data points for spatial extent discrimination or spatial frequency discrimination were fitted with Gaussian functions using the least square method, and the spatial extent and spatial frequency entropies were estimated from the standard deviation of these Gaussian functions. Then, joint entropy was obtained by multiplying the square root of space extent entropy times the spatial frequency entropy. We compared our results to the theoretical minimum for unidimensional Gábor functions, 1/4? or 0.0796. At low and intermediate spatial frequencies and high contrasts, joint entropy reached levels below the theoretical minimum, suggesting non-linear interactions between two or more visual mechanisms. We concluded that non-linear interactions of visual pathways, such as the M and P pathways, could explain joint entropy values below the theoretical minimum at low and intermediate spatial frequencies and high contrasts. These non-linear interactions might be at work at intermediate and high contrasts at all spatial frequencies once there was a substantial decrease in joint entropy for these stimulus conditions when contrast was raised.
Related JoVE Video
Multifocal electroretinography after high dose chloroquine therapy for malaria.
J Ophthalmic Vis Res
PUBLISHED: 12-19-2013
Show Abstract
Hide Abstract
To investigate changes in multifocal electroretinography (mfERG) parameters associated with high dose chloroquine therapy for treatment of malaria in the Amazonia region of Brazil.
Related JoVE Video
Acaricidal efficacy of topical formulation of fipronil in naturally infested dogs in Amazonic region, Brazil.
Rev Bras Parasitol Vet
PUBLISHED: 11-21-2013
Show Abstract
Hide Abstract
This study was conducted to show the effectiveness of a novel formulation of fipronil in a spot-on formulation for the therapeutic and preventive control of Rhipicephalus sanguineus in naturally infested dogs. Ticks on all dogs were counted at the moment of treatment and weekly after treatment (therapeutic efficacy) or infestation (preventive efficacy). The profile of the therapeutic efficacy for Rhipicephalus sanguineus suggested that the formulation was able to control the Ixodid species for at least 42 days after the treatment.
Related JoVE Video
The effects of dopamine on root growth and enzyme activity in soybean seedlings.
Plant Signal Behav
PUBLISHED: 06-24-2013
Show Abstract
Hide Abstract
In the present study, we investigated the effects of dopamine, an allelochemical exuded from the velvetbean (Mucuna pruriens L DC. var utilis), on the growth and cell viability of soybean (Glycine max L. Merrill) roots. We analyzed the effects of dopamine on superoxide dismutase, phenylalanine ammonia-lyase and cell wall-bound peroxidase activities as well as its effects on lignin contents in the roots. Three-day-old seedlings were cultivated in half-strength Hoagland nutrient solution (pH 6.0), without or with 0.25 to 1.0 mM dopamine, in a growth chamber (25°C, 12L:12D photoperiod, irradiance of 280 ?mol m(-2) s(-1)) for 24 h. In general, the length, fresh weight and dry weight of roots, cell viability, PAL and POD activities decreased, while SOD activities increased after dopamine treatment. The content of lignin was not altered. The data demonstrate the susceptibility of soybean to dopamine and reinforce the role of this catecholamine as a strong allelochemical. The results also suggest that dopamine-induced inhibition in soybean roots is not related to the production of lignin, but may be related to damage caused by reactive oxygen species.
Related JoVE Video
Should we worry about periacetabular interference gaps in hip resurfacing?
Clin. Orthop. Relat. Res.
PUBLISHED: 05-29-2013
Show Abstract
Hide Abstract
Press-fit acetabular component seating in hip resurfacing can be challenging as a strong interference fit is required. It has not been established whether reducing the acetabular underream minimizes incomplete component seating or leads to increased acetabular loosening.
Related JoVE Video
Occurrence of Shiga-toxigenic Escherichia coli in Stomoxys calcitrans (Diptera: Muscidae).
Rev Bras Parasitol Vet
PUBLISHED: 05-17-2013
Show Abstract
Hide Abstract
This study aimed to verify the occurrence of Shiga toxin-producing Escherichia coli (STEC) strains in three distinct anatomic parts of the stable fly Stomoxys calcitrans by multiplex polymerase chain reaction (PCR Multiplex). According to the results obtained, E. coli was identified in 19.5% of the stable flies. Shiga toxin genes were detected in 13% of the E. coli isolated, most frequently from the surface, followed by abdominal digestive tract and mouth apparatus of insects, respectively. This is the first study to detect presence of STEC in Stomoxys calcitrans in Brazil; it has also revealed the potential role of stable flies as carriers of pathogenic bacterial agents.
Related JoVE Video
The role of CCNH Val270Ala (rs2230641) and other nucleotide excision repair polymorphisms in individual susceptibility to well-differentiated thyroid cancer.
Oncol. Rep.
PUBLISHED: 05-03-2013
Show Abstract
Hide Abstract
Well-differentiated thyroid cancer (DTC) is the most common form of thyroid cancer (TC); however, with the exception of radiation exposure, its etiology remains largely unknown. Several single nucleotide polymorphisms (SNPs) have previously been implicated in DTC risk. Nucleotide excision repair (NER) polymorphisms, despite having been associated with cancer risk at other locations, have received little attention in the context of thyroid carcinogenesis. In order to evaluate the role of NER pathway SNPs in DTC susceptibility, we performed a case-control study in 106 Caucasian Portuguese DTC patients and 212 matched controls. rs2230641 (CCNH), rs2972388 (CDK7), rs1805329 (RAD23B), rs3212986 (ERCC1), rs1800067 (ERCC4), rs17655, rs2227869 (ERCC5), rs4253211 and rs2228529 (ERCC6) were genotyped using TaqMan® methodology, while conventional PCR-RFLP was employed for rs2228000 and rs2228001 (XPC). When considering all DTC cases, only rs2230641 (CCNH) was associated with DTC risk; a consistent increase in overall DTC risk was observed for both the heterozygous genotype (OR=1.89, 95% CI=1.14-3.14) and the variant allele carriers (OR=1.79, 95% CI=1.09-2.93). Histological stratification analysis confirmed an identical effect on follicular TC (OR=2.72, 95% CI=1.19-6.22, for heterozygous; OR=2.44, 95% CI=1.07?5.55, for variant allele carriers). Considering papillary TC, the rs2228001 (XPC) variant genotype was associated with increased risk (OR=2.33, 95% CI=1.05-5.16), while a protective effect was observed for rs2227869 (ERCC5) (OR=0.26, 95% CI=0.08?0.90, for heterozygous; OR=0.25, 95% CI=0.07-0.86, for variant allele carriers). No further significant results were observed. Our results suggest that NER polymorphisms such as rs2230641 (CCNH) and, possibly, rs2227869 (ERCC5) and rs2228001 (XPC), may influence DTC susceptibility. However, larger studies are required to confirm these results.
Related JoVE Video
Development and morphology of the inverted yolk sac in the guinea pig (Cavia porcellus).
Theriogenology
PUBLISHED: 02-15-2013
Show Abstract
Hide Abstract
Although the guinea pig is an important animal model for human placentation, aspects of fetal nutrition are not fully understood, especially in regard to the yolk sac that is regarded to be essential for early development of the embryo. We investigated differentiation by means of histology, histochemistry, immunohistochemistry, and transmission electron microscopy. Data suggest that the guinea pigs yolk sac was not sufficiently developed to facilitate substantial fetal nutrition in early pregnancy. On Day 12, it was a flat, inverted, but avascular structure. This was followed by differentiation to form the typical, highly villous and vascularized condition of advanced gestation. Finally, the yolk sac degenerated toward term. We suggest that the guinea pig and other caviomorphs rely predominantly on hemotrophic nutrition via the placenta even in very early pregnancy. In contrast to the general pattern of mammals, histiotrophic nutrition via yolk sac routes seems to be most essential during mid-gestation.
Related JoVE Video
Induction of sister chromatid exchange by acrylamide and glycidamide in human lymphocytes: role of polymorphisms in detoxification and DNA-repair genes in the genotoxicity of glycidamide.
Mutat. Res.
PUBLISHED: 01-31-2013
Show Abstract
Hide Abstract
Acrylamide (AA) is a probable human carcinogen generated in carbohydrate-rich foodstuffs upon heating. Glycidamide (GA), formed via epoxidation, presumably mediated by cytochrome P450 2E1, is considered to be the active metabolite that plays a central role in the genotoxicity of AA. The aim of this work was to evaluate the cytogenetic damage induced by AA and GA in cultured human lymphocytes by use of the sister chromatid exchange (SCE) assay. Furthermore, this report addresses the role of individual genetic polymorphisms in key genes involved in detoxification and DNA-repair pathways (BER, NER, HRR and NHEJ) on the induction of SCE by GA. While AA induced the number of SCE/metaphase only slightly, especially for the highest concentration tested (2000?M), GA markedly induced SCEs in a concentration-dependent manner up to concentrations of 750?M, leading to an increase in SCEs of up to about 10-fold compared with controls. By combining DNA damage in GA-treated lymphocytes and data on polymorphisms, associations between the induction of SCEs with GSTP1 (Ile105Val) and GSTA2 (Glu210Ala) genotypes are suggested.
Related JoVE Video
Distribution and hybridization of Culex pipiens forms in Greece during the West Nile virus outbreak of 2010.
Infect. Genet. Evol.
PUBLISHED: 01-20-2013
Show Abstract
Hide Abstract
In 2010, an outbreak of West Nile virus (WNV) infections occurred in the region of Thessaloniki, Central Macedonia, in northern Greece. During this period, Culex pipiens sensu stricto mosquitoes were found infected by WNV lineage 2. Cx. pipiens s.s. presents two distinct biological forms, denoted molestus and pipiens. Hybrids between the two forms may potentiate the accidental transmission of WNV to humans. We have genetically characterized the form composition of Cx. pipiens s.s. samples collected during the outbreak from the region of Thessaloniki, where WNV cases occurred, and from the region Schinias-Marathonas, with no reported cases at the time. Information on bird fauna was also obtained for the two regions. Application of the CQ11FL diagnostic marker revealed a 350 bp variant of the pipiens-specific allele. Sympatric pipiens and molestus populations were detected in Thessaloniki, whereas Schinias-Marathonas presented a more genetically homogenous molestus population. A pattern of asymmetric introgression between molestus and pipiens was also observed in Thessaloniki. The presence of hybrids between molestus and pipiens forms suggests a greater receptivity of the Thessaloniki region for the establishment of WNV zoonotic cycles. However, the Schinias-Marathonas region also displayed characteristics to sustain WNV transmission cycles. These observations highlight the importance of maintaining active surveillance systems in selected regions geographically located within the range of major migratory bird flyways.
Related JoVE Video
Intraoral schwannoma: a case report.
Oral Maxillofac Surg
PUBLISHED: 01-13-2013
Show Abstract
Hide Abstract
Schwannoma (neurilemmona) is a benign nerve sheath composed of Schwann cells. This tumor represents 1% of all benign tumor, usually observed in the head and neck region, and in, rare cases, this lesion may be observed in oral cavity. They are usually asymptomatic, do not recur, and malignant transformation is rare. We presented a case report of schwannoma in the lower lips.
Related JoVE Video
Feeding patterns of molestus and pipiens forms of Culex pipiens (Diptera: Culicidae) in a region of high hybridization.
Parasit Vectors
PUBLISHED: 01-09-2013
Show Abstract
Hide Abstract
Two biological forms of the mosquito Culex pipiens s.s., denoted pipiens and molestus, display behavioural differences that may affect their role as vectors of arboviruses. In this study, the feeding patterns of molestus and pipiens forms were investigated in Comporta (Portugal), where high levels of inter-form admixture have been recorded.
Related JoVE Video
Visual evoked cortical potential (VECP) elicited by sinusoidal gratings controlled by pseudo-random stimulation.
PLoS ONE
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The contributions of contrast detection mechanisms to the visual cortical evoked potential (VECP) have been investigated studying the contrast-response and spatial frequency-response functions. Previously, the use of m-sequences for stimulus control has been almost restricted to multifocal electrophysiology stimulation and, in some aspects, it substantially differs from conventional VECPs. Single stimulation with spatial contrast temporally controlled by m-sequences has not been extensively tested or compared to multifocal techniques. Our purpose was to evaluate the influence of spatial frequency and contrast of sinusoidal gratings on the VECP elicited by pseudo-random stimulation. Nine normal subjects were stimulated by achromatic sinusoidal gratings driven by pseudo random binary m-sequence at seven spatial frequencies (0.4-10 cpd) and three stimulus sizes (4°, 8°, and 16° of visual angle). At 8° subtence, six contrast levels were used (3.12-99%). The first order kernel (K1) did not provide a consistent measurable signal across spatial frequencies and contrasts that were tested-signal was very small or absent-while the second order kernel first (K2.1) and second (K2.2) slices exhibited reliable responses for the stimulus range. The main differences between results obtained with the K2.1 and K2.2 were in the contrast gain as measured in the amplitude versus contrast and amplitude versus spatial frequency functions. The results indicated that K2.1 was dominated by M-pathway, but for some stimulus condition some P-pathway contribution could be found, while the second slice reflected the P-pathway contribution. The present work extended previous findings of the visual pathways contribution to VECP elicited by pseudorandom stimulation for a wider range of spatial frequencies.
Related JoVE Video
Relationship between food intake and sleep pattern in healthy individuals.
J Clin Sleep Med
PUBLISHED: 12-16-2011
Show Abstract
Hide Abstract
The purpose of this study was to analyze the relationship between food intake and sleep patterns in healthy individuals.
Related JoVE Video
Multi-locus species tree of the chub genus Squalius (Leuciscinae: Cyprinidae) from western Iberia: new insights into its evolutionary history.
Genetica
PUBLISHED: 02-24-2011
Show Abstract
Hide Abstract
The phylogenetic relationships of the genus Squalius are believed to be well established based on the mitochondrial cytochrome b gene. Here, we inferred the phylogenetic relationships of all species inhabiting most of the western Iberia river systems using a nuclear multi-locus approach and different species tree methods: concatenation and coalescent-based methods (BEST and minimize-deep-coalescence). The dataset comprised sequences of seven coding and three non-coding regions belonging to seven nuclear genes, which were chosen to cover multiple biological functions: amh, bmp4, ef1a, egr2, irbp, rh and rpl8. We provide evidence for a conflicting topology between the nuDNA species tree and the widely reported mtDNA gene tree. S. pyrenaicus is rendered paraphyletic in all nuDNA species trees, with populations of the Tagus/Colares clustering with S. carolitertii, while populations from the Guadiana, Sado and Almargem form a separate clade. Although a larger sampling size encompassing the full spectrum of Squalius populations in western Iberia is still needed to fully elucidate the phylogeography and species delimitation of this genus, our results suggest that the two S. pyrenaicus clades may represent different species.
Related JoVE Video
Mosquito fauna on the Cape Verde Islands (West Africa): an update on species distribution and a new finding.
J. Vector Ecol.
PUBLISHED: 12-24-2010
Show Abstract
Hide Abstract
To evaluate the risk of transmission of vector-borne diseases, regular updates of the geographic distribution of insect vectors are required. In the archipelago of Cape Verde, nine mosquito species have been reported. Of these, four are major vectors of diseases that have been present in the archipelago: yellow fever, lymphatic filariasis, malaria and, currently, an outbreak of dengue. In order to assess variation in mosquito biodiversity, we have carried out an update on the distribution of the mosquito species in Cape Verde, based on an enquiry of 26 unpublished technical reports (1983-2006) and on the results of an entomological survey carried out in 2007. Overall, there seems to be a general trend for an expansion of biological diversity in the islands. Mosquito species richness was negatively correlated with the distance of the islands from the mainland but not with the size of the islands. Human- and/or sporadic climatic-mediated events of dispersal may have contributed to a homogenization of species richness regardless of island size but other ecological factors may also have affected the mosquito biogeography in the archipelago. An additional species, Culex perexiguus, was collected for the first time in the archipelago during the 2007 survey.
Related JoVE Video
Castes in the neotropical social wasp Leipomeles dorsata (Fabricius) (Hymenoptera: Vespidae): a window for workers achieving a new status in the colony.
Neotrop. Entomol.
PUBLISHED: 09-30-2010
Show Abstract
Hide Abstract
Morphometric studies performed in several species of Neotropical social wasps from the tribe Epiponini showed that in some species there are marked differences between castes, while other species present highly distinct castes with differences only in ovarian development. This work analyzed females from six colonies of the social wasp Leipomeles dorsata (Fabricius) in which queens (egglayers) and workers showed differences in ovarian development and coloration. We propose that wasps with developed ovaries (egglayers) and coloration similar to those of workers are possibly intermediates that obtained the status of queens in the colony.
Related JoVE Video
The role of common variants of non-homologous end-joining repair genes XRCC4, LIG4 and Ku80 in thyroid cancer risk.
Oncol. Rep.
PUBLISHED: 09-03-2010
Show Abstract
Hide Abstract
Variations, such as single nucleotide polymorphisms (SNPs) in DNA damage repair genes have been pointed out as possible factors to cancer predisposition. Ionizing radiation (IR) induces DNA double strand breaks (DSBs) and is the main recognized risk factor for thyroid cancer. However, most of the patients do not show chronic contact with IR and the other factors have non-concordant data. Thus, thyroid cancer could be due to gene variations in association with certain exogenous factors. One of the pathways that repair DSBs is DNA non-homologous end-joining (NHEJ) that comprises several polymorphic genes. We intend to study the role of polymorphic variants in XRCC4, LIG4 and Ku80 genes, since there is scarcity of data on the role of these genes in thyroid cancer susceptibility. We carried out a hospital-based case-control study in a Caucasian Portuguese population (109 patients and 217 controls) to estimate the potential role of the XRCC4 (N298S and T134I), LIG4 (T9I) and Ku80 (Ex21-238Gright curved arrow A, Ex21+338Tright curved arrow C, Ex21-352Cright curved arrow A, Ex21+466Aright curved arrow G) polymorphisms in the individual susceptibility for this disease. The results here reported do not associate these polymorphisms with susceptibility for non-familial thyroid cancer. However, when the data were analyzed according to the type of tumour, significant results for Ku80 Ex21-238Gright curved arrow A and Ex21+466Aright curved arrow G were found for papillary tumours (adjusted OR = 2.281; 95% CI =; 1.063-4.894; P=0.034). Taken together these results suggest that some of these variants in NHEJ genes can contribute to thyroid cancer susceptibility. However, further studies with a larger sample size will be needed to support our results.
Related JoVE Video
Ultrastructural aspects of lingual papillae in squirrel monkey (Saimiri sciureus).
Microsc. Res. Tech.
PUBLISHED: 07-29-2010
Show Abstract
Hide Abstract
Saimiri sciureus is one of the smallest Cebidae native of Amazon region and also found at the biological reserve of northeast Atlantic forest. It is an omnivore animal, with diversified diet that directly influences the lingual mucosa, which includes certain types of papillae with different organization levels. The present study attempted to describe the morphological and ultrastructure aspects of the dorsal surface of the S. sciureus. Five tongues of de S. sciureus were analyzed from three males and two females who died from natural causes and were obtained from breeding colonies of CENP-Ananindeua-PA. Main macroscopic features were a general triangular shape with a craniocaudal elongation pointed apex. Tissue samples--apex, body, and root of tongue--were fixed in modified Karnovsky solution, following standard scanning protocol, mounted in stubs, coated by gold, and analyzed by Scanning Electron Macroscopy (SEM). Four types of papillae were described: filiform (along all tissue extension with 154 ?m of diameter), fungiform (along all tissue extension with 272 ?m of diameter), vallate [just three units in caudal (dorsal) portion with 830 ?m of diameter] and foliate (one pair at caudolateral surface with ? 13 projections and 3000 ?m in length). Data analysis indicates that the distribution and ultra structural morphology of the S. sciureus lingual papillae are some similar to other primates.
Related JoVE Video
Knocking down Cav1 calcium channels implicated in Th2 cell activation prevents experimental asthma.
Am. J. Respir. Crit. Care Med.
PUBLISHED: 02-18-2010
Show Abstract
Hide Abstract
Th2 cells orchestrate allergic asthma and the cytokines they produce (IL-4, IL-5, and IL-13) are deleterious in allergy. Therefore, it is important to identify key signaling molecules expressed by Th2 cells that are essential for their function. We have previously shown that dihydropyridines selectively modulate Th2 cell functions.
Related JoVE Video
Development of an immunoassay for ciprofloxacin based on phage-displayed antibody fragments.
J. Immunol. Methods
PUBLISHED: 02-10-2010
Show Abstract
Hide Abstract
The widespread use of ciprofloxacin in human, animal and plant health has raised an environmental problem, paralleled by several other antibiotics. The aim of this work is the development of a rapid and sensitive ELISA assay for ciprofloxacin, which can constitute an alternative to time-consuming HPLC methods. For this purpose, we worked with antibody fragments, instead of whole antibodies, and used magnetic beads as solid support. Ciprofloxacin was successfully immobilized onto this support with a carbodiimide-mediated reaction. A library of phage particles that express human single-chain antibodies at their surface was then screened with an optimized protocol. Several positive fragments were isolated and identified as being V(L) fragments. These were then fully characterized. A reproducible competitive ELISA was developed using the magnetic beads - ciprofloxacin as support and the phages displaying the V(L) fragment as recognition entity. This assay showed limits of detection and quantification of 9.3 nM and 33 nM, respectively. Also, competitive ELISAs with ciprofloxacin homologues and other molecules showed cross-reactivities lower than 12%.
Related JoVE Video
Post-intubation tracheal injury: report of three cases and literature review.
J Bras Pneumol
PUBLISHED: 09-09-2009
Show Abstract
Hide Abstract
Post-intubation tracheal injury is a rare and potentially fatal complication. Among the most common causes, cuff overinflation and repetitive attempts of orotracheal intubation in emergency situations are paramount. Diagnosis is based on clinical and radiological suspicion, confirmed by fiberoptic bronchoscopy. Both conservative and surgical management apply, and the decision-making process depends on the patient profile (comorbidities, respiratory stability), characteristics of the lesion (size and location) and the time elapsed between the occurrence of the injury and the diagnosis. We report the cases of three patients presenting tracheal laceration due to traumatic orotracheal intubation, two submitted to surgical treatment and one submitted to conservative treatment.
Related JoVE Video
Breast cancer risk and common single nucleotide polymorphisms in homologous recombination DNA repair pathway genes XRCC2, XRCC3, NBS1 and RAD51.
Cancer Epidemiol
PUBLISHED: 08-04-2009
Show Abstract
Hide Abstract
The possible role for DNA repair deficiencies in cancer development, namely in breast cancer has been the subject of increasing interest since it has been reported that breast cancer patients might be deficient in the repair of DNA damage. Exposure to ionizing radiation has been pointed out as a risk factor for breast cancer, and the type of DNA lesions induced by this carcinogen can be repaired by homologous recombination DNA repair (HRR) pathway. To evaluate the potential modifying role of some single nucleotide polymorphisms (SNP) in HRR involved genes on the individual susceptibility to breast cancer we carried out a hospital based case-control study in a Caucasian Portuguese population (289 histological confirmed breast cancer patients and 548 control individuals). We genotyped 4 SNPs in 4 different HRR pathway genes, XRCC2 (Ex3+442G>A, R188H, rs3218536), XRCC3 (Ex8-5C>T, T241M, rs861539), NBS1 (Ex5-32C>G, E185Q, rs1805794) and RAD51 5UTR (Ex1-59G>T, rs1801321), tagging 41 SNPs in these genes. The frequency of the different polymorphisms in the Portuguese control population is similar to the ones reported for other Caucasian populations, and the deviation of the Hardy-Weinberg equilibrium was only observed for the XRCC2 (Ex3+442G>A, R188H, rs3218536) polymorphism in the control population. The results obtained, after logistic regression analysis, did not reveal a major role of these polymorphisms on breast cancer susceptibility. However, when the population was stratified according to breast feeding (women that breast fed and women that never breast fed) it is observed, in women that never breast fed, that the heterozygous individuals for the XRCC2 (Ex3+442G>A, R188H, rs3218536) polymorphism have a decreased risk for breast cancer [adjusted OR=0.45; 95% CI=0.22-0.92] (P=0.03). Additionally, after stratification according to menopausal status, our results suggest that post-menopausal women carrying at least one variant allele for the XRCC3 (Ex8-5C>T, T241M, rs861539) polymorphism have a lower risk for breast cancer [adjusted OR=0.67; 95% CI, 0.47-0.94] (P=0.03). Most of the studies suggest that breastfeeding may be responsible for 2/3 of the estimate reduction of breast cancer. The longer the duration of breastfeeding the lower the potential risk associated with breast cancer. Therefore, in our study the potential protective role of the variant allele of XRCC2 (Ex3+442G>A, R188H, rs3218536), in never breast fed women, might be related with a more efficient DNA repair activity.
Related JoVE Video
Asymmetric introgression between sympatric molestus and pipiens forms of Culex pipiens (Diptera: Culicidae) in the Comporta region, Portugal.
BMC Evol. Biol.
PUBLISHED: 07-09-2009
Show Abstract
Hide Abstract
Culex pipiens L. is the most widespread mosquito vector in temperate regions. This species consists of two forms, denoted molestus and pipiens, that exhibit important behavioural and physiological differences. The evolutionary relationships and taxonomic status of these forms remain unclear. In northern European latitudes molestus and pipiens populations occupy different habitats (underground vs. aboveground), a separation that most likely promotes genetic isolation between forms. However, the same does not hold in southern Europe where both forms occur aboveground in sympatry. In these southern habitats, the extent of hybridisation and its impact on the extent of genetic divergence between forms under sympatric conditions has not been clarified. For this purpose, we have used phenotypic and genetic data to characterise Cx. pipiens collected aboveground in Portugal. Our aims were to determine levels of genetic differentiation and the degree of hybridisation between forms occurring in sympatry, and to relate these with both evolutionary and epidemiological tenets of this biological group.
Related JoVE Video
A theoretical antioxidant pharmacophore for resveratrol.
Eur J Med Chem
PUBLISHED: 07-02-2009
Show Abstract
Hide Abstract
The structure-activity relationship has been used to study the determination of antioxidant pharmacophore for resveratrol using quantum chemistry calculations by the Functional of Density Theory method. According to the geometry obtained by using a B3LYP/6-31G(*), the HOMO, ionization potential, bond dissociation energies, stabilization energies, and spin density distribution, the electron or hydrogen abstraction in para position is more favored than in meta positions for resveratrol and related derivatives because of the resonance effects. Comparison with structurally related compounds revealed that the antioxidant pharmacophore of resveratrol is 4-hydroxystilbene. Spin distribution showed that the pi-type electron system determines the stability of radicals and the unpaired electrons are mainly distributed to the O-atom in para position, double bond, and B-benzene ring. The antioxidant activity of resveratrol is related to the stabilization energy of 4-hydroxystilbene in resveratrol hydroxylated derivatives. Furthermore, the results explain the activity difference between resveratrol and its hydroxylated derivatives.
Related JoVE Video
An improved bait method for collecting Hymenoptera, especially social wasps (Vespidae: Polistinae).
Neotrop. Entomol.
PUBLISHED: 04-01-2009
Show Abstract
Hide Abstract
In this work, an alternative method for the capture of neotropical social wasps is described, which may supplement or replace the procedures commonly used in wasp surveys. The method was tested in a seasonal semideciduous forest in the northwest of São Paulo State, collecting a larger number of species and a greater abundance of social wasps and of other Hymenoptera than other methods also used in the same area, namely Malaise traps, bottle traps and meat baits. The proposed method was adapted from Wille (1962) who used an attractive solution based on water and honey for bee attraction. In here, the attractive solution was based on water, salt and crystal sugar, and was effective in attracting bees and solitary wasps, but mainly social wasps, which is the group of interest for this report.
Related JoVE Video
Dengue maculopathy: visual electrophysiology and optical coherence tomography.
Doc Ophthalmol
PUBLISHED: 01-06-2009
Show Abstract
Hide Abstract
The objective of this study was to evaluate the visual loss due to dengue fever using retinal and cortical electrophysiology and retinal imaging. The participants were three female patients with low visual acuity after dengue fever. They were evaluated by routine ophthalmological investigations, transient pattern electroretinogram (tPERG), transient pattern visual evoked cortical potential (tPVECP), and retinal optical coherence tomography (retinal OCT). tPERG and tPVECP amplitude (microV) and implicit time (ms) were the parameters evaluated using OCT retinal thickness (microm) and reflectivity. All patients presented low visual acuity and scotomata with or without changes in the oculus fundus. tPERG from two patients showed decreased amplitude or absence of the main components; it was not possible to record a reliable response in the third patient due to excessive blinking. tPVECP at 0.5 cpd was normal in all three patients, while at 2 cpd the main components were absent in one patient and normal in the other two patients. OCT image was abnormal in two patients, one of them with high reflectance areas and another with decreased retinal thickness (the third patient was not studied with this technique).The dengue fever can lead to visual impairment detectable by ophthalmological exams such as angiography, retinography, and OCT imaging, as well as retinal and cortical electrophysiology. Dengue maculopathy which could be caused by vascular alterations and/or aberrant immune response after infection may result in temporary or permanent visual losses.
Related JoVE Video
The Culex pipiens complex in continental Portugal: distribution and genetic structure.
J. Am. Mosq. Control Assoc.
Show Abstract
Hide Abstract
Portugal is a southern European country that displays favorable ecological conditions for the establishment of West Nile virus (WNV) transmission cycles. Competent mosquito vector species are present throughout the country. Among the species with reported cases of WNV isolation in Portugal, Culex pipiens is the most ubiquitous and abundant mosquito. This species exhibits two biological forms with differences in host preferences. The molestus form has a greater tendency to feed upon humans and other mammals whereas the pipiens form prefers avian hosts. In northern latitudes, both forms are physically separated, with molestus occupying underground habitats and pipiens being found aboveground. However, the warmer climatic conditions of southern regions such as Portugal may favor the sympatric occurrence of both forms hence promoting interform hybridization. Genetic introgression between molestus and pipiens forms may result in a higher propensity for admixed populations to serve as bridge-vectors of WNV between humans and birds. Here we revise our present knowledge on the distribution, role in WNV transmission and genetic structure of the Cx. pipiens complex in continental Portugal. We focus on recent findings of sympatric molestus and pipiens populations that display considerable levels of hybridization and discuss the epidemiological repercussions of this occurrence.
Related JoVE Video
Oxidative stress in malaria.
Int J Mol Sci
Show Abstract
Hide Abstract
Malaria is a significant public health problem in more than 100 countries and causes an estimated 200 million new infections every year. Despite the significant effort to eradicate this dangerous disease, lack of complete knowledge of its physiopathology compromises the success in this enterprise. In this paper we review oxidative stress mechanisms involved in the disease and discuss the potential benefits of antioxidant supplementation as an adjuvant antimalarial strategy.
Related JoVE Video
[Neuroimaging in Human Immunodeficiency Virus infection].
Acta Med Port
Show Abstract
Hide Abstract
Central Nervous System (CNS) infection by Human Immunodeficiency Virus (HIV) occurs early in the course of the disease and is associated with changes that can reach any level of the neuroaxis. Neuroimaging plays an increasingly important role both in diagnosis and in longitudinal monitoring of these complications, which can be divided into three major categories: injuries directly associated with HIV, opportunistic infections and malignancies.
Related JoVE Video
Hybridization and population structure of the Culex pipiens complex in the islands of Macaronesia.
Ecol Evol
Show Abstract
Hide Abstract
The Culex pipiens complex includes two widespread mosquito vector species, Cx. pipiens and Cx. quinquefasciatus. The distribution of these species varies in latitude, with the former being present in temperate regions and the latter in tropical and subtropical regions. However, their distribution range overlaps in certain areas and interspecific hybridization has been documented. Genetic introgression between these species may have epidemiological repercussions for West Nile virus (WNV) transmission. Bayesian clustering analysis based on multilocus genotypes of 12 microsatellites was used to determine levels of hybridization between these two species in Macaronesian islands, the only contact zone described in West Africa. The distribution of the two species reflects both the islands biogeography and historical aspects of human colonization. Madeira Island displayed a homogenous population of Cx. pipiens, whereas Cape Verde showed a more intriguing scenario with extensive hybridization. In the islands of Brava and Santiago, only Cx. quinquefasciatus was found, while in Fogo and Maio high hybrid rates (?40%) between the two species were detected. Within the admixed populations, second-generation hybrids (?50%) were identified suggesting a lack of isolation mechanisms. The observed levels of hybridization may locally potentiate the transmission to humans of zoonotic arboviruses such as WNV.
Related JoVE Video
Melanoma chemotherapy leads to the selection of ABCB5-expressing cells.
PLoS ONE
Show Abstract
Hide Abstract
Metastatic melanoma is the most aggressive skin cancer. Recently, phenotypically distinct subpopulations of tumor cells were identified. Among them, ABCB5-expressing cells were proposed to display an enhanced tumorigenicity with stem cell-like properties. In addition, ABCB5(+) cells are thought to participate to chemoresistance through a potential efflux function of ABCB5. Nevertheless, the fate of these cells upon drugs that are used in melanoma chemotherapy remains to be clarified. Here we explored the effect of anti-melanoma treatments on the ABCB5-expressing cells. Using a melanoma xenograft model (WM266-4), we observed in vivo that ABCB5-expressing cells are enriched after a temozolomide treatment that induces a significant tumor regression. These results were further confirmed in a preliminary study conducted on clinical samples from patients that received dacarbazine. In vitro, we showed that ABCB5-expressing cells selectively survive when exposed to dacarbazine, the reference treatment of metastatic melanoma, but also to vemurafenib, a new inhibitor of the mutated kinase V600E BRAF and other various chemotherapeutic drugs. Our results show that anti-melanoma chemotherapy might participate to the chemoresistance acquisition by selecting tumor cell subpopulations expressing ABCB5. This is of particular importance in understanding the relapses observed after anti-melanoma treatments and reinforces the interest of ABCB5 and ABCB5-expressing cells as potential therapeutic targets in melanoma.
Related JoVE Video
Odontoma associated with calcifying cystic odontogenic tumor in deciduous dentition: case report.
Oral Maxillofac Surg
Show Abstract
Hide Abstract
Initially described by Gorlin et al. in 1962, the calcifying cystic odontogenic tumor (CCOT) may be associated with unerupted teeth, ameloblastomas, adenomatoid odontogenic tumors, and, in many cases, with odontomas. It is rare in patients in the first decade of life, particularly involving deciduous teeth. Surgery is the treatment of choice, with low recurrence rates.
Related JoVE Video
Antifungal activity of lectins against yeast of vaginal secretion.
Braz. J. Microbiol.
Show Abstract
Hide Abstract
Lectins are carbohydrate-binding proteins of non-imune origin. This group of proteins is distributed widely in nature and they have been found in viruses, microorganisms, plants and animals. Lectins of plants have been isolated and characterized according to their chemical, physical-chemical, structural and biological properties. Among their biological activities, we can stress its fungicidal action. It has been previously described the effect of the lectins Dviol, DRL, ConBr and LSL obtained from the seeds of leguminous plants on the growth of yeasts isolated from vaginal secretions. In the present work the experiments were carried out in microtiter plates and the results interpreted by both methods: visual observations and a microplate reader at 530nm. The lectin concentrations varied from 0.5 to 256?g/mL, and the inoculum was established between 65-70% of trammitance. All yeast samples isolated from vaginal secretion were evaluated taxonomically, where were observed macroscopic and microscopic characteristics to each species. The LSL lectin did not demonstrate any antifungal activity to any isolate studied. The other lectins DRL, ConBr and DvioL, showed antifungal potential against yeast isolated from vaginal secretion. These findings offering offer a promising field of investigation to develop new therapeutic strategies against vaginal yeast infections, collaborating to improve womens health.
Related JoVE Video
Bone marrow cells of swine: collection and separation.
Microsc. Res. Tech.
Show Abstract
Hide Abstract
Bone marrow is a source of stem cells for greater and easier access, which is widely studied as a provider of hematopoietic and mesenchymal cells for various purposes, mainly therapeutic by the advances in research involving cell therapy. The swine is an animal species commonly used in the pursuit of development of experimental models. Thus, this study aimed to standardize protocol for collection and separation of bone marrow in swines, since this species is widely used as experimental models for various diseases. Twelve animals were used, which underwent bone marrow puncture with access from the iliac crest and cell separation by density gradient followed by a viability test with an average of 98% of viable cells. Given our results, we can ensure the swine as an excellent model for obtaining and isolation of mononuclear cells from bone marrow, stimulating several studies addressing the field of cell therapy.
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.