Investigation of citrullinemia type I variants by in vitro expression studies

Mild citrullinemia is an allelic variant of classical citrullinemia type I also caused by deficiency of the urea cycle enzyme argininosuccinate synthetase (ASS). Affected patients comprise a biochemical but no clinical phenotype. However, there is no reliable parameter allowing conclusions regarding the course of the disorder or its type of manifestation. The aim of this study was to test the importance of varying levels of ASS residual activities for the severity at diagnosis. Bacterial in vitro expression studies allowed the enzymatic analysis of purified wild-type and the mutant ASS proteins p.Ala118Thr (c.352G>A), p.Trp179Arg (c.535T>C), p.Val263Met (c.787G>A), p.Arg265Cys (c.793C>T), p.Met302Val (c.904A>G), p.Gly324Ser (c.970G>A), p.Gly362Val (c.1085G>T), and p.Gly390Arg (c.1168G>A). In the chosen system, classical mutations do not show any significant enzymatic activity, whereas mutations associated with a mild course yield significant ASS activity levels. The mutation p.Ala118Thr (c.352G>A) impresses by a high residual activity (62%) but a severe reduction of affinity toward the substrates citrulline and aspartate. This mutation was identified in a hitherto healthy female adult with no history of known citrullinemia who had died during the postpartum period from hyperammonemic coma. The results of this study suggest that even a high level of residual ASS activity is not a reliable prognostic marker for an uneventful clinical course. Determination of ASS residual activities, therefore, cannot help in anticipating the risk of metabolic derangement. This study should guide clinicians as well as patients with mild citrullinemia toward a lifelong awareness of the disorder.     

Coxiella burnetii infection among blood donors during the 2009 Q-fever outbreak in The Netherlands

BACKGROUND: In 2007, 2008, and 2009 outbreaks of Q‐fever occurred in the Netherlands with increasing magnitude. The 2009 outbreak with 2354 reported cases is the largest human Q‐fever outbreak ever recorded. To assess the extent of infection and the safety of donated blood, we tested local blood donations for presence of Coxiella burnetii antibodies and DNA. STUDY DESIGN AND METHODS: Starting May 2009, more than 40,000 serum samples were collected from all consenting blood donors in the areas with high Q‐fever incidence. The 1004 samples from the areas with the highest number of reported cases were tested for C. burnetii DNA by polymerase chain reaction; seroprevalence and incidence were determined using enzyme‐linked immunosorbent assay and immunofluorescence assays (IFAs) in the subset of 543 donors of whom a follow‐up sample was available. RESULTS: A total of 6 of 1004 donor samples tested reactive for C. burnetii DNA. Confirmatory testing (IFA) on the index and follow‐up samples demonstrated seroconversion in two donors, high‐level preexisting antibodies in one donor, and no seroconversion in three donors. Immunoglobulin (Ig)G testing of the 543 serum pairs showed that 66 were reactive in the latest sample, of which 10 represented seroconversions. CONCLUSION: In the area with highest incidence during a large Q‐fever outbreak, 3 of 1004 blood donations contained C. burnetii DNA (0.3%; 95% confidence interval, 0.1%‐1.0%). A total of 66 of 543 (12.2%) donors tested positive for anti‐Coxiella IgG. Ten seroconversions were detected, resulting in an incidence of 5.7% per year, which is more than 10‐fold higher than the local number of reported clinical cases (0.47% per year). [Correction added after online publication 14‐Jul‐11: high‐level existing antibodies has been updated to highlevel preexisting antibodies.]     

Etomidate increases susceptibility to pneumonia in trauma patients

Purpose

To investigate the impact of etomidate on the rate of hospital-acquired pneumonia (HAP) in trauma patients and the effects of hydrocortisone in etomidate-treated patients.

Methods

This was a sub-study of the HYPOLYTE multi-centre, randomized, double-blind, placebo-controlled trial of hydrocortisone in trauma patients (NCT00563303). Inclusion criterion was trauma patient with mechanical ventilation (MV) of?≥48?h. The use of etomidate was prospectively collected. Endpoints were the results of the cosyntropin test and rate of HAP on day 28 of follow-up.

Results

Of the 149 patients enrolled in the study, 95 (64?%) received etomidate within 36?h prior to inclusion. 79 (83?%) of 95 patients receiving etomidate and 34 of the 54 (63?%) not receiving etomidate had corticosteroid insufficiency (p?=?0.006). The administration of etomidate did not alter basal cortisolemia (p?=?0.73), but it did decrease the delta of cortisolemia at 60?min (p?=?0.007). There was a correlation between time from etomidate injection to inclusion in the study and sensitivity to corticotropin (R ²?=?0.19; p?=?0.001). Forty-nine (51.6?%) patients with etomidate and 16 (29.6?%) patients without etomidate developed HAP by day 28 (p?=?0.009). Etomidate was associated with HAP on day 28 in the multivariate analysis (hazard ratio 2.48; 95?% confidence interval 1.19–5.18; p?=?0.016). Duration of MV with or without etomidate was not significantly different (p?=?0.278). Among etomidate-exposed patients, 18 (40?%) treated with hydrocortisone developed HAP compared with 31 (62?%) treated with placebo (p?=?0.032). Etomidate-exposed patients treated with hydrocortisone had fewer ventilator days (p?Conclusions Among the patients enrolled in the study, etomidate did not alter basal cortisolemia, but it did decrease reactivity to corticotropin. We suggest that in trauma patients, etomidate is an independent risk factor for HAP and that the administration of hydrocortisone should be considered after etomidate use.     

You may need the vagus nerve to understand pathophysiology and to treat diseases

Can different pathophysiological mechanisms and risk factors leading to various diseases be linked with altered transmission of signals by one common pathway? The present article provides evidence for the hypothesis that adequate vagal nerve activity reduces the risk of major diseases, via common basic mechanisms and interim risk factors. These diseases include cardiovascular disease, cancer, Alzheimer's disease and the metabolic syndrome. Three basic mechanisms contribute to such illnesses: local oxidative stress and DNA damage, inflammatory reactions and excessive sympathetic responses, all of which are inhibited by vagal nerve activity. Efferent vagal activity that can be non-invasively measured by HRV (heart rate variability), derived from an ECG, is inversely related to all three basic mechanisms, to various risk factors (e.g. diabetes and dyslipidaemia) and, more broadly, to the diseases as well. Finally, vagal activity is proposed to moderate the effects of risk factors on developing such illnesses. By proposing an integrative neurobiological model of major diseases, identifying people at risk for, and treating patients with, such diseases may be done more efficiently. People with low HRV may be identified and subsequently treated by vagus nerve activation to possibly prevent or treat such illnesses. This proposed disease paradigm may have important preventative and therapeutic implications, whose clinical effects need to be investigated.     

Geographical Differences in Autoantibodies and Anti-infectious Agents Antibodies Among Healthy Adults

Much is known about the geoepidemiology of defined autoimmune diseases (AD); however, there is currently limited data regarding the prevalence of autoantibodies among healthy populations of different geographical areas. The aim of this study was to evaluate a large profile of autoantibodies in healthy adults from distinct global regions as well as the prevalence of anti-infectious agents antibodies in those regions. Sera samples from 557 healthy donors were obtained at six centers located in different countries (i.e., Italy, Netherlands, Israel, Mexico, Columbia, Papua New Guinea (Kitavans)). Sera were tested for the presence of antinuclear antibodies (ANA) and autoantibodies associated with thrombophilia, vasculitis, and gastrointestinal (GI) disease. Sera samples were also screened for antibodies against infectious agents (i.e., EBV, CMV, HBV, Helicobacter pylori, Treponema pallidum, and Toxoplasma gondii). Tests were performed using the BioPlex 2200 or ELISA kits (Bio-Rad Laboratories, USA). We found a significant gradient of ANA positivity among the groups: 45% of Columbians, 38% of Kitavans, 26% of Mexicans, 12% of Italians, 12% of Dutch, and 11% of Israelis were ANA positive. Geographical differences were also observed regarding the prevalence of specific autoantibodies, namely ANA: anti-dsDNA, chromatin, SmRNP, Ro/SSA, La/SSB, Scl70; GI associated: antigliadin; and thrombophilia-associated: anti-??2GP1 and prothrombin. Additionally, significant differences were observed regarding serological markers of all infectious agents screened. The observed variance between healthy ethno-geographical distinct populations in prevalence of autoantibodies may represent different genetic or environmental (e.g., prior exposure to infection) influences. Thus may illuminate possible causes of geoepidemiological differences in AD.     

Brief Report: Recovery of assessed global fish stocks remains uncertain

Concerns over overexploitation have fueled an ongoing debate on the current state and future prospects of global capture fisheries, associated threats to marine biodiversity, and declining yields available for human consumption. Management reforms have aimed to reduce fishing pressure and recover depleted stocks to biomass and exploitation rates that allow for maximum sustainable yield. Recent analyses suggest that scientifically assessed stocks, contributing over half of global marine fish catch, have, on average, reached or even exceeded these targets, suggesting a fundamental shift in the effectiveness of fisheries governance. However, such conclusions are based on calculations requiring specific choices to average over high interstock variability to derive a global trend. Here we evaluate the robustness of these conclusions by examining the distribution of recovery rates across individual stocks and by applying a diversity of plausible averaging techniques. We show that different methods produce markedly divergent trajectories of global fisheries status, with 4 of 10 methods suggesting that recovery has not yet been achieved, with up to 48% of individual stocks remaining below biomass targets and 40% exploited above sustainable rates. Furthermore, recent rates of recovery are only marginally different from zero, with up to 46% of individual stocks trending downward in biomass and 29% of stocks trending upward in exploitation rate. These results caution against overoptimistic assessments of fisheries writ large and support a precautionary management approach to ensure full rebuilding of depleted fisheries worldwide.