Desmosomal Antigens Are Not Recognized by the Majority of Pemphigus Autoimmune Sera

Sera from 7 patient with pemphigus vulgaris and both mouse and rabbit antisera against bovine epidermal desmosomes contained antibodies that bound to cell surface components of the spinous layer of bovine epidermis. The antidesmosomal sera show significant binding to purified desmosomal proteins in an enzyme-linked immunosorbent assay (ELISA). Two of 7 pemphigus sera bound to desmosomal protein-coated microtiter plates at low dilution titers. Two of 6 normal human sera also bound to desmosomal protein-coated microtiter plates at titers comparable to those of the pemphigus sera. Indirect immunofluorescent labeling of frozen sections of monkey esophagus revealed striking differences in the distribution of pemphigus antigens and desmosomal constituents. Pemphigus antisera produced rather uniform fluorescence around the borders of spinous cells of the esophageal epithelium, while anti-desmosomal antibodies bound in a punctate pattern. Anti-desmosomal antibodies labeled cells of the basal layer in a strongly punctate pattern. Only 1 pemphigus serum appreciably labeled basal cells. Two of 3 anti-desmosomal antisera bound avidly in the upper differentiating layers of the epithelium. Pemphigus antibodies did not. Pemphigus sera that reacted with desmosomal proteins in ELISA were absorbed by affinity chromatography on immobilized desmosomal proteins. This treatment did not alter the immunofluorescent labeling patterns produced by these sera. From these results we conclude that the pemphigus autoantibodies studied here bind to epithelial cell surface antigens which are distinguishable from the structural components of desmosomes

Towards Targeted Screening for Acute HIV Infections in British Columbia

Background: Our objective was to describe the characteristics of acute and established HIV infections diagnosedin the Canadian province of British Columbia. Province-wide HIV testing and surveillance data were analyzed toinform recommendations for targeted use of screening algorithms to detect acute HIV infections.Methods: Acute HIV infection was defined as a confirmed reactive HIV p24 antigen test (or HIV nucleic acid test), anon-reactive or reactive HIV EIA screening test and a non-reactive or indeterminate Western Blot. Characteristics ofunique individuals were identified from the British Columbia HIV/AIDS Surveillance System. Primary drug resistanceand HIV subtypes were identified by analyzing HIV pol sequences from residual sera from newly infectedindividuals.Results: From February 2006 to October 2008, 61 individuals met the acute HIV infection case definition,representing 6.2% of the 987 newly diagnosed HIV infections during the analysis period. Acute HIV infection caseswere more likely to be men who have sex with men (crude OR 1.71; 95% CI 1.01-2.89], to have had a documentedprevious negative HIV test result (crude OR 2.89; 95% CI 1.52-5.51), and to have reported a reason for testing dueto suspected seroconversion symptoms (crude OR 5.16; 95% CI 2.88-9.23). HIV subtypes and rates of transmitteddrug resistance across all classes of drugs were similar in persons with both acute and established HIV infections.Conclusions: Targeted screening to detect acute HIV infection is a logical public health response to the HIVepidemic. Our findings suggest that acute HIV infection screening strategies, in our setting, are helpful for earlydiagnosis in men who have sex with men, in persons with seroconversion symptoms and in previously negativerepeat testers

Germ-Layer Surface Tensions and “Tissue Affinities” inRana pipiensGastrulae: Quantitative Measurements

AbstractThe morphogenetic properties causing germ-layer spreading and stratification in amphibian gastrulation were called “tissue affinities” by Holtfreter. The differential adhesion hypothesis (DAH) attributes such liquidlike tissue rearrangements to forces generated by intercellular adhesions within and between the migrating cell populations. This theory predicts that, among the primary germ layers, the cohesiveness of deep ectoderm should be the greatest, that of deep mesoderm should be intermediate, and that of deep endoderm should be the least. Also, the cohesiveness of differentiating neural ectoderm should increase after induction, causing it to internalize and segregate from epidermis. The DAH also explains why the cohesiveness of “liquid” tissues, whose cells are free to rearrange, should be measurable as tissue surface tensions. Using a specially designed tissue surface tensiometer, we demonstrate that (i) aggregates ofRana pipiensdeep germ layers do possess liquid-like surface tensions, (ii) their surface tension values lie in precisely the sequence necessary to account for germ-layer stratificationin vitroandin vivo,and (iii) the surface tension of deep ectoderm just underlain by the archenteron roof is twice that of not-yet-underlain deep ectoderm. These measurements provide direct, quantitative evidence that the “tissue affinities” governing germ-layer flow during early stages of vertebrate morphogenesis are reflected in tissue surface tensions

Moving Forward Moving Backward: Directional Sorting of Chemotactic Cells due to Size and Adhesion Differences

Differential movement of individual cells within tissues is an important yet poorly understood process in biological development. Here we present a computational study of cell sorting caused by a combination of cell adhesion and chemotaxis, where we assume that all cells respond equally to the chemotactic signal. To capture in our model mesoscopic properties of biological cells, such as their size and deformability, we use the Cellular Potts Model, a multiscale, cell-based Monte Carlo model. We demonstrate a rich array of cell-sorting phenomena, which depend on a combination of mescoscopic cell properties and tissue level constraints. Under the conditions studied, cell sorting is a fast process, which scales linearly with tissue size. We demonstrate the occurrence of “absolute negative mobility”, which means that cells may move in the direction opposite to the applied force (here chemotaxis). Moreover, during the sorting, cells may even reverse the direction of motion. Another interesting phenomenon is “minority sorting”, where the direction of movement does not depend on cell type, but on the frequency of the cell type in the tissue. A special case is the cAMP-wave-driven chemotaxis of Dictyostelium cells, which generates pressure waves that guide the sorting. The mechanisms we describe can easily be overlooked in studies of differential cell movement, hence certain experimental observations may be misinterpreted

Evaluation of a new airborne microwave remote sensing radiometer by measuring the salinity gradients across the shelf of the Great Barrier Reef lagoon

Over the last ten years, some operational airborne remote sensing systems have become available for mapping surface salinity over large areas in near real time. A new dual-polarized Polarimetric L-band Multibeam Radiometer (PLMR) has been developed to improve accuracy and precision when compared with previous instrument generations. This paper reports on the first field evaluation of the performance of the PLMR by measuring salinity gradients in the central Great Barrier Reef. Before calibration, the raw salinity values of the PLMR and conductivity-temperature-depth (CTD) differed by 3-6 psu. The calibration, which uses in situ salinity data to remove long-term drifts in the PLMR as well as environmental effects such as surface roughness and radiation from the sky and atmosphere, was carried out by equating the means of the PLMR and CTD salinity data over a subsection of the transect, after which 85% of the salinity values between the PLMR and CTD are within 0.1 psu along the complete transect. From offshore to inshore across the shelf, the PLMR shows an average cross-shelf salinity increase of about 0.4 psu and a decrease of 2 psu over the inshore 20 km at -19deg S (around Townsville) and -18deg S (around Lucinda), respectively. The average cross-shelf salinity increase was 0.3 psu for the offshore 100 km over all transects. These results are consistent with the in situ CTD results. This survey shows that PLMR provided an effective method of rapidly measuring the surface salinity in near real time when a calibration could be made

Evaluation of ADCP wave, WAVEWATCH III and HF radar data on the GBR

Wave climate can have a very significant impact on the dynamics of the near-coastal oceans, including geomorphology and currents. This study is a preliminary investigation of the suitability and compatibility of a wave-capable Acoustic Doppler Current Profiler (ADCP) mooring, an HF ocean radar system and the numerical model WAVEWATCH III (WW3), with the focus on the area of the Capricorn and Bunker Groups of reefs and islands, Australia

Diagnostic technologies in practice: gay men's narratives of acute or recent HIV infection diagnosis.

Diagnosing HIV-positive gay men through enhanced testing technologies that detect acute HIV infection (AHI) or recent HIV infection provides opportunities for individual and population health benefits. We recruited 25 men in British Columbia who received an acute (n = 13) or recent (n = 12) HIV diagnosis to engage in a longitudinal multiple-methods study over one year or longer. Our thematic analysis of baseline qualitative interviews revealed insights within men's accounts of technologically mediated processes of HIV discovery and diagnosis. Our analysis illuminated the dialectic of new HIV technologies in practice by considering the relationship between advances in diagnostics (e.g., nucleic acid amplification tests) and the users of these medical technologies in clinical settings (e.g., clients and practitioners). Technological innovations and testing protocols have shifted experiences of learning of one's HIV-positive status; these innovations have created new diagnostic categories that require successful interpretation and translation to be rendered meaningful, to alleviate uncertainty, and to support public health objectives

A concerted appeal for international cooperation in preclinical stroke research

Special report.-- et al.Peer reviewe

The Governance of Core Competencies for Public Health: A Rapid Review of the Literature

Core competencies for public health (CCPH) define the knowledge, skills, and attitudes required of a public health workforce. Although numerous sets of CCPH have been established, few studies have systematically examined the governance of competency development, review, and monitoring, which is critical to their implementation and impact. This rapid review included 42 articles. The findings identified examples of collaboration and community engagement in governing activities (e.g., using the Delphi method to develop CCPH) and different ways of approaching CCPH review and revision (e.g., every 3 years). Insights on monitoring and resource management were scarce. Preliminary lessons emerging from the findings point towards the need for systems, structures, and processes that support ongoing reviews, revisions, and monitoring of CCPH