Comparative Scanning, Transmission and Atomic Force Microscopy of the Microtubular Cytoskeleton in Fenestrated Liver Endothelial Cells

Endothelial fenestrae control the exchange of fluids, solutes and particles between the sinusoidal lumen and the microvillous surface of the parenchymal cells. Fenestrae have a critical dimension in the order of 150-200 nm, making it necessary to use microscopes with a resolution better than the light microscope. Comparative whole-mount preparations of isolated, purified and cultured rat liver sinusoidal endothelial cells (LEC) were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM). Examination of detergent-extracted LEC by SEM and TEM shows an integral cytoskeleton: sieve plates are delineated by a sieve plate-associated cytoskeleton ring and fenestrae by a fenestrae-associated cytoskeleton ring. By using microtubule altering agents we could demonstrate: (1) the architectural role of microtubules in arranging fenestrae, (2) the existence of a population of microtubules resistant against low temperature and colchicine, (3) the ability of LEC to shift the microtubule assembly-disassembly steady state under various conditions, (4) and the necessity of an intact microtubular cytoskeleton to support the increase in the number of fenestrae after cytochalasin B. Topographical examinations of AFM images revealed that sieve plates are delineated by elevated borders, probably projections of the underlying tubular cytoskeleton

Butterfly dichromatism primarily evolved via Darwin's, not Wallace's, model

Sexual dimorphism is typically thought to result from sexual selection for elaborated male traits, as proposed by Darwin. However, natural selection could reduce expression of elaborated traits in females, as proposed by Wallace. Darwin and Wallace debated the origins of dichromatism in birds and butterflies, and although evidence in birds is roughly equal, if not in favor of Wallace's model, butterflies lack a similar scale of study. Here, we present a large-scale comparative phylogenetic analysis of the evolution of butterfly coloration, using all European non-hesperiid butterfly species (n = 369). We modeled evolutionary changes in coloration for each species and sex along their phylogeny, thereby estimating the rate and direction of evolution in three-dimensional color space using a novel implementation of phylogenetic ridge regression. We show that male coloration evolved faster than female coloration, especially in strongly dichromatic clades, with male contribution to changes in dichromatism roughly twice that of females. These patterns are consistent with a classic Darwinian model of dichromatism via sexual selection on male coloration, suggesting this model was the dominant driver of dichromatism in European butterflies

Cerebral small vessel disease genomics and its implications across the lifespan

White matter hyperintensities (WMH) are the most common brain-imaging feature of cerebral small vessel disease (SVD), hypertension being the main known risk factor. Here, we identify 27 genome-wide loci for WMH-volume in a cohort of 50,970 older individuals, accounting for modification/confounding by hypertension. Aggregated WMH risk variants were associated with altered white matter integrity (p = 2.5×10-7) in brain images from 1,738 young healthy adults, providing insight into the lifetime impact of SVD genetic risk. Mendelian randomization suggested causal association of increasing WMH-volume with stroke, Alzheimer-type dementia, and of increasing blood pressure (BP) with larger WMH-volume, notably also in persons without clinical hypertension. Transcriptome-wide colocalization analyses showed association of WMH-volume with expression of 39 genes, of which four encode known drug targets. Finally, we provide insight into BP-independent biological pathways underlying SVD and suggest potential for genetic stratification of high-risk individuals and for genetically-informed prioritization of drug targets for prevention trials.Peer reviewe

Exploring the uptake of COVID-19 vaccination amongst respiratory therapists in Canada

Introduction/background COVID-19 vaccination uptake rates and responses by Canadian respiratory therapists (RTs) were investigated along with factors that may be shown to play a role in vaccination hesitancy. Methods An anonymous survey using SurveyMonkey® on vaccination uptake rates, responses and attitudes was made available to student RTs, graduate RTs and registered RTs in Canada from July to October of 2021. Pearson's chi-square tests were performed to evaluate association between vaccination status and the other categorical parameters evaluated. Results A total of 1013 surveys (8.0% of target population) were completed fully and included in the data analysis. Of the surveyed RT population, 90.42% received their vaccination as soon as it was made available compared to Canada's Ministry of Health's published rate at the time of 86.27% for all Canadian healthcare workers. There was a significant (p = 0.013) association between early vaccination and age and a significant (p = 0.036) association between vaccination status and a participant's response on whether or not they have a family member or know someone who has had COVID-19. There was also a significant (p \< 0.001) association between vaccination status and attitudes towards trusting science to develop safe, effective, new vaccines and trusting the Ministry of Health to ensure that vaccines are safe. There was no significant association between vaccination status and gender, province/territory of residency/work, level of education and level of involvement with COVID-19 patients. Conclusion The results suggest that RT groups across Canada had higher early vaccination uptake rates than general healthcare worker groups and that age, relationship to people with COVID-19 and trust in science played a significant role in their vaccination uptake rates

Genoprotective effect of the Chinese herbal decoction xiao jian zhong tang

The Chinese herbal decoction formula Xiao Jian Zhong Tang (XJZT) is one of the classic formulas from the classic traditional Chinese medicine (TCM). Previous studies on XJZT found that it is effective for treating peptic ulcer, irritable bowel syndrome, functional gastroenteritis and similar psychosomatic disorders of the digestive organs. It has also been shown that all the herbs used in XJZT contain antioxidants. In this study, we investigated the in vitro DNA protection effect of the individual herb extracts and the whole formula. Water extract of the herbs and XJZT were used to pre-treat human lymphocytes. The lymphocytes were then exposed to hydrogen peroxide. The in vitro DNA protection effect of the herbs was investigated by comet assay. No DNA protective effect (P \u3c 0.05) was found for individual herb extracts, but XJZT showed protection of human lymphocytic DNA upon oxidative stress (P \u3c 0.05). The in vitro DNA protection effect of XJZT was conferred by the synergistic effect of the herbs, while the individual herbs had no such effect

In vivo genoprotective effect against UV irradiation by red grapes (Vitis vinifera L.) juice

The genoprotective effect of a single ingestion of red grape juice on human DNA was explored. Twenty subjects (10 males and 10 females) were recruited for this study. Subjects were randomly assigned to two groups and each group consisted of five males and five females. Ten were asked to drink 250 mL commercially available grape juice without any addictive while the other ten in the control group consumed water instead. Blood samples were taken immediately before and two hours after ingestion of either grape juice or water. The blood samples were then embedded in agarose and irradiated with ultraviolet-B followed by the comet assay. The slides were stained with Giemsa stain and DNA damage was assessed through the grading of the comet head and tail. Results showed a statistically significant decrease in DNA damage with grape juice consumption compared to the control group. This study illustrated that red grape juice drink was sufficient to protect cellular DNA from oxidative stress at least within two hours

In vitro study of DNA protective effect of duzhong (eucommia ulmoides oliv) using single cell gel electrophoresis

Introduction: DuZhong (Eucommia ulmoidesOliv.) is a Chinese traditional medicinal herb with antioxidant actions toward oxidative damage which is well documented in different scientific researches. Comet assay (single cell gel electrophoresis) is a well-developed technique for the analysis on DNA damage in single cell level. The purpose of this study is to compare aqueous and alcoholic crude extract of DuZhong cortex for its potential in vitro DNA protective effect on human lymphocytes against oxidative stress environment. Design: Venous blood was collected from three healthy adult volunteers followed by isolation of lymphocytes. DuZhong extract was obtained by boiling inwater and ultrasound-assisted alcoholic extraction. Lymphocytes were incubated to different dilutions of DuZhong extract before oxidative challenge with hydrogen peroxide solution in standard and lysed cell comet assay. The nucleus of lymphocyte was stained and manually scored under fluorescent microscope. Results: Significant reduction in length of comet was only found in 0.1mg/ L of aqueous extract undergone lysed cell comet assay while alcoholic extract did not show significant reduction with same other experimental setting. No significant reduction in comet length and no obvious difference were seen among aqueous and alcoholic extracts in standard comet assay. The result demonstrated that DuZhong shows some DNA protection action against oxidant stress for specific experimental condition

Antioxidative properties of traditional herbal medicines and the application of comet assay on antioxidative study

Traditional Chinese medicine (TCM) in single herb or formula prescription has been used for thousands of years. Many of them possess antioxidant activity and the activity may contribute the therapeutic effect. This paper would review the relationship of traditional herbal medicine and antioxidant with particular reference to ginseng. This medicinal herb has been used worldwide with extensive tonic effect. The comet assay, a technique for DNA protecting and damaging investigation would be introduced and the application of comet assay on TCM would be discussed

Protective effect of grape seed extracts on human lymphocytes: a preliminary study

Grape seed extracts (GSEs) possess a broad spectrum of antioxidative properties that protects various cells from free radicals and oxidative stress. In this study, the genoprotective effect of GSE on human lymphocytic DNA was studied using standard and lysed cell comet assays. Lymphocytes from 5 healthy subjects were pretreated with GSE in different concentrations. The standard and lysed cell comet assays were performed on treated, untreated, challenged, and unchallenged cells in parallel. Cells were then subjected to an oxidant challenge induced with 5-min exposures to hydrogen peroxide. In the standard comet assay, GSE significantly diminished hydrogen-peroxide-induced DNA damage in a dose-dependent manner. In the lysed cell assay, however, the antioxidant effect was diminished at a higher GSE concentration. Data indicate that the cell membrane might play a role in limiting cellular access to antioxidants, which directly affects the genoprotective or potential pro-oxidant effect of antioxidants on human DNA. Using both standard and lysed cell comet assays in parallel could be a useful way to elucidate the mechanism of protection or damage by antioxidants