Dibutyltin disrupts glucocorticoid receptor function and impairs glucocorticoid-induced suppression of cytokine production

BACKGROUND: Organotins are highly toxic and widely distributed environmental chemicals. Dibutyltin (DBT) is used as stabilizer in the production of polyvinyl chloride plastics, and it is also the major metabolite formed from tributyltin (TBT) in vivo. DBT is immunotoxic, however, the responsible targets remain to be defined. Due to the importance of glucocorticoids in immune-modulation, we investigated whether DBT could interfere with glucocorticoid receptor (GR) function. METHODOLOGY: We used HEK-293 cells transiently transfected with human GR as well as rat H4IIE hepatoma cells and native human macrophages and human THP-1 macrophages expressing endogenous receptor to study organotin effects on GR function. Docking of organotins was used to investigate the binding mechanism. PRINCIPAL FINDINGS: We found that nanomolar concentrations of DBT, but not other organotins tested, inhibit ligand binding to GR and its transcriptional activity. Docking analysis indicated that DBT inhibits GR activation allosterically by inserting into a site close to the steroid-binding pocket, which disrupts a key interaction between the A-ring of the glucocorticoid and the GR. DBT inhibited glucocorticoid-induced expression of phosphoenolpyruvate carboxykinase (PEPCK) and tyrosine-aminotransferase (TAT) and abolished the glucocorticoid-mediated transrepression of TNF-alpha-induced NF-kappaB activity. Moreover, DBT abrogated the glucocorticoid-mediated suppression of interleukin-6 (IL-6) and TNF-alpha production in lipopolysaccharide (LPS)-stimulated native human macrophages and human THP-1 macrophages. CONCLUSIONS: DBT inhibits ligand binding to GR and subsequent activation of the receptor. By blocking GR activation, DBT may disturb metabolic functions and modulation of the immune system, providing an explanation for some of the toxic effects of this organotin.

Democracy a Casualty of Voter-Suppression Politics

A Montana Public Radio Commentary by Evan Barrett. Published newspaper columns written by Evan Barrett on this topic, which vary somewhat in content from this commentary, appeared in the following publications: Missoulian, August 8, 2014 Independent Record, August 13, 2014 Billings Gazette, August 18, 2014 Montana Standard, August 19, 2014

The feasibility of non-viral gene transfer to the diaphragm in vivo

Gene transfer using electroporation is an essential method for the study of developmental biology, especially to understand the internal control of degeneration and apoptosis of the muscle cells that occurs earlier and quicker than the usual degeneration process occurring by aging. Such experimental studies may have a role in developing new strategies for treating patients suffering from inherited primary myopathies such as Duchenne muscular dystrophy (DMD). The present study was designed to evaluate the feasibility of electroporation mediated transfer of reporter genes to the diaphragm in vivo. This is the first report of gene transfer of naked plasmid DNA into the diaphragm muscle in vivo using electroporation. Our results showed that in vivo gene transfer of naked plasmid DNA into the diaphragm muscle using electroporation is feasible.

Sexual transmission of HIV according to viral load and antiretroviral therapy: systematic review and meta-analysis

OBJECTIVES: To synthesize the evidence on the risk of HIV transmission through unprotected sexual intercourse according to viral load and treatment with combination antiretroviral therapy (ART). DESIGN: Systematic review and meta-analysis. METHODS: We searched Medline, Embase and conference abstracts from 1996-2009. We included longitudinal studies of serodiscordant couples reporting on HIV transmission according to plasma viral load or use of ART and used random-effects Poisson regression models to obtain summary transmission rates [with 95% confidence intervals, (CI)]. If there were no transmission events we estimated an upper 97.5% confidence limit. RESULTS: We identified 11 cohorts reporting on 5021 heterosexual couples and 461 HIV-transmission events. The rate of transmission overall from ART-treated patients was 0.46 (95% CI 0.19-1.09) per 100 person-years, based on five events. The transmission rate from a seropositive partner with viral load below 400 copies/ml on ART, based on two studies, was zero with an upper 97.5% confidence limit of 1.27 per 100 person-years, and 0.16 (95% CI 0.02-1.13) per 100 person-years if not on ART, based on five studies and one event. There were insufficient data to calculate rates according to the presence or absence of sexually transmitted infections, condom use, or vaginal or anal intercourse. CONCLUSION: Studies of heterosexual discordant couples observed no transmission in patients treated with ART and with viral load below 400 copies/ml, but data were compatible with one transmission per 79 person-years. Further studies are needed to better define the risk of HIV transmission from patients on ART.

Switching to second-line antiretroviral therapy in resource-limited settings: comparison of programmes with and without viral load monitoring

BACKGROUND: In high-income countries, viral load is routinely measured to detect failure of antiretroviral therapy (ART) and guide switching to second-line ART. Viral load monitoring is not generally available in resource-limited settings. We examined switching from nonnucleoside reverse transcriptase inhibitor (NNRTI)-based first-line regimens to protease inhibitor-based regimens in Africa, South America and Asia. DESIGN AND METHODS: Multicohort study of 17 ART programmes. All sites monitored CD4 cell count and had access to second-line ART and 10 sites monitored viral load. We compared times to switching, CD4 cell counts at switching and obtained adjusted hazard ratios for switching (aHRs) with 95% confidence intervals (CIs) from random-effects Weibull models. RESULTS: A total of 20 113 patients, including 6369 (31.7%) patients from 10 programmes with access to viral load monitoring, were analysed; 576 patients (2.9%) switched. Low CD4 cell counts at ART initiation were associated with switching in all programmes. Median time to switching was 16.3 months [interquartile range (IQR) 10.1-26.6] in programmes with viral load monitoring and 21.8 months (IQR 14.0-21.8) in programmes without viral load monitoring (P < 0.001). Median CD4 cell counts at switching were 161 cells/microl (IQR 77-265) in programmes with viral load monitoring and 102 cells/microl (44-181) in programmes without viral load monitoring (P < 0.001). Switching was more common in programmes with viral load monitoring during months 7-18 after starting ART (aHR 1.38; 95% CI 0.97-1.98), similar during months 19-30 (aHR 0.97; 95% CI 0.58-1.60) and less common during months 31-42 (aHR 0.29; 95% CI 0.11-0.79). CONCLUSION: In resource-limited settings, switching to second-line regimens tends to occur earlier and at higher CD4 cell counts in ART programmes with viral load monitoring compared with programmes without viral load monitoring.

Outcomes of the South African National Antiretroviral Treatment Programme for children: the IeDEA Southern Africa collaboration

OBJECTIVES: To assess paediatric antiretroviral treatment (ART) outcomes and their associations from a collaborative cohort representing 20% of the South African national treatment programme. DESIGN AND SETTING: Multi-cohort study of 7 public sector paediatric ART programmes in Gauteng, Western Cape and KwaZulu-Natal provinces. SUBJECTS: ART-naive children (< or = 16 years) who commenced treatment with > or = 3 antiretroviral drugs before March 2008. OUTCOME MEASURES: Time to death or loss to follow-up were assessed using the Kaplan-Meier method. Associations between baseline characteristics and mortality were assessed with Cox proportional hazards models stratified by site. Immune status, virological suppression and growth were described in relation to duration of ART. RESULTS: The median (interquartile range) age of 6 078 children with 9 368 child-years of follow-up was 43 (15 - 83) months, with 29% being < 18 months. Most were severely ill at ART initiation. More than 75% of children were appropriately monitored at 6-monthly intervals with viral load suppression (< 400 copies/ml) being 80% or above throughout 36 months of treatment. Mortality and retention in care at 3 years were 7.7% (95% confidence interval 7.0 - 8.6%) and 81.4% (80.1 - 82.6%), respectively. Together with young age, all markers of disease severity (low weight-for-age z-score, high viral load, severe immune suppression, stage 3/4 disease and anaemia) were independently associated with mortality. CONCLUSIONS: Dramatic clinical benefit for children accessing the national ART programme is demonstrated. Higher mortality in infants and those with advanced disease highlights the need for early diagnosis of HIV infection and commencement of ART.

Serum metabolomics reveals irreversible inhibition of fatty acid beta-oxidation through the suppression of PPARalpha activation as a contributing mechanism of acetaminophen-induced hepatotoxicity

Metabolic bioactivation, glutathione depletion, and covalent binding are the early hallmark events after acetaminophen (APAP) overdose. However, the subsequent metabolic consequences contributing to APAP-induced hepatic necrosis and apoptosis have not been fully elucidated. In this study, serum metabolomes of control and APAP-treated wild-type and Cyp2e1-null mice were examined by liquid chromatography-mass spectrometry (LC-MS) and multivariate data analysis. A dose-response study showed that the accumulation of long-chain acylcarnitines in serum contributes to the separation of wild-type mice undergoing APAP-induced hepatotoxicity from other mouse groups in a multivariate model. This observation, in conjunction with the increase of triglycerides and free fatty acids in the serum of APAP-treated wild-type mice, suggested that APAP treatment can disrupt fatty acid beta-oxidation. A time-course study further indicated that both wild-type and Cyp2e1-null mice had their serum acylcarnitine levels markedly elevated within the early hours of APAP treatment. While remaining high in wild-type mice, serum acylcarnitine levels gradually returned to normal in Cyp2e1-null mice at the end of the 24 h treatment. Distinct from serum aminotransferase activity and hepatic glutathione levels, the pattern of serum acylcarnitine accumulation suggested that acylcarnitines can function as complementary biomarkers for monitoring the APAP-induced hepatotoxicity. An essential role for peroxisome proliferator-activated receptor alpha (PPARalpha) in the regulation of serum acylcarnitine levels was established by comparing the metabolomic responses of wild-type and Ppara-null mice to a fasting challenge. The upregulation of PPARalpha activity following APAP treatment was transient in wild-type mice but was much more prolonged in Cyp2e1-null mice. Overall, serum metabolomics of APAP-induced hepatotoxicity revealed that the CYP2E1-mediated metabolic activation and oxidative stress following APAP treatment can cause irreversible inhibition of fatty acid oxidation, potentially through suppression of PPARalpha-regulated pathways.

BCL6 suppression of BCL2 via Miz1 and its disruption in diffuse large B cell lymphoma

The BCL6 proto-oncogene encodes a transcriptional repressor that is required for germinal center (GC) formation and whose deregulation by genomic lesions is implicated in the pathogenesis of GC-derived diffuse large B cell lymphoma (DLBCL) and, less frequently, follicular lymphoma (FL). The biological function of BCL6 is only partially understood because no more than a few genes have been functionally characterized as direct targets of BCL6 transrepression activity. Here we report that the anti-apoptotic proto-oncogene BCL2 is a direct target of BCL6 in GC B cells. BCL6 binds to the BCL2 promoter region by interacting with the transcriptional activator Miz1 and suppresses Miz1-induced activation of BCL2 expression. BCL6-mediated suppression of BCL2 is lost in FL and DLBCL, where the 2 proteins are pathologically coexpressed, because of BCL2 chromosomal translocations and other mechanisms, including Miz1 deregulation and somatic mutations in the BCL2 promoter region. These results identify an important function for BCL6 in facilitating apoptosis of GC B cells via suppression of BCL2, and suggest that blocking this pathway is critical for lymphomagenesis.

Randomized, double-blind comparative trial of subunit and virosomal influenza vaccines for immunocompromised patients

BACKGROUND: To our knowledge, no study to date has compared the effects of a subunit influenza vaccine with those of a virosomal influenza vaccine on immunocompromised patients. METHODS: A prospective, double-blind, randomized study was conducted to compare the immunogenicity and reactogenicity of subunit and virosomal influenza vaccines for adult patients who had an immunosuppressive disease or who were immunocompromised as a result of treatment. RESULTS: There were 304 patients enrolled in our study: 131 with human immunodeficiency virus (HIV) infection, 47 with a chronic rheumatologic disease, 74 who underwent a renal transplant, 47 who received long-term hemodialysis, and 5 who had some other nephrologic disease. There were 151 patients who received the subunit vaccine and 153 patients who received the virosomal vaccine. A slightly higher percentage of patients from the subunit vaccine group were protected against all 3 influenza vaccine strains after being vaccinated, compared with patients from the virosomal vaccine group (41% vs. 30% of patients; P = .03). Among HIV-infected patients, the level of HIV RNA, but not the CD4 cell count, was an independent predictor of vaccine response. Among renal transplant patients, treatment with mycophenolate significantly reduced the immune response to vaccination. The 2 vaccines were comparable with regard to the frequency and severity of local and systemic reactions within 7 days after vaccination. Disease-specific scores for the activity of rheumatologic diseases did not indicate flare-ups 4-6 weeks after vaccination. CONCLUSIONS: For immunosuppressed patients, the subunit vaccine was slightly more immunogenic than the virosomal vaccine. The 2 vaccines were comparable with regard to reactogenicity. Vaccine response decreased with increasing degree of immune suppression. Among HIV-infected patients, the viral load, rather than the CD4 cell count, predicted the protective immune response to the vaccine. CLINICAL TRIALS REGISTRATION: NCT00783380 .

Systematic Functional Analysis of BicD Serine Phosphorylation and Intragenic Suppression of a Female Sterile Allele of BicD

Protein phosphorylation is involved in posttranslational control of essentially all biological processes. Using mass spectrometry, recent analyses of whole phosphoproteomes led to the identification of numerous new phosphorylation sites. However, the function of most of these sites remained unknown. We chose the Drosophila Bicaudal-D protein to estimate the importance of individual phosphorylation events. Being involved in different cellular processes, BicD is required for oocyte determination, for RNA transport during oogenesis and embryogenesis, and for photoreceptor nuclei migration in the developing eye. The numerous roles of BicD and the available evidence for functional importance of BicD phosphorylation led us to identify eight phosphorylation sites of BicD, and we tested a total of 14 identified and suspected phosphoserine residues for their functional importance in vivo in flies. Surprisingly, all these serines turned out to be dispensable for providing sufficient basal BicD activity for normal growth and development. However, in a genetically sensitized background where the BicD(A40V) protein variant provides only partial activity, serine 103 substitutions are not neutral anymore, but show surprising differences. The S103D substitution completely inactivates the protein, whereas S103A behaves neutral, and the S103F substitution, isolated in a genetic screen, restores BicD(A40V) function. Our results suggest that many BicD phosphorylation events may either be fortuitous or play a modulating function as shown for Ser(103). Remarkably, amongst the Drosophila serines we found phosphorylated, Ser(103) is the only one that is fully conserved in mammalian BicD.

Age-dependent suppression of SERCA2a mRNA in pediatric atrial myocardium

Differential expression of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2a) and phospholamban (PLB) has been shown in heart failure and atrial arrhythmias. We investigated the influence of volume overload and age on their expression in pediatric atrial myocardium. Right atrial specimens from 18 children with volume overloaded right atrium (VO) and 12 patients without overload were studied. Each group was further divided into patients less than and older than 12 months of age. Only in the younger patients SERCA2a was significantly reduced in the VO group. In younger patients PLB mRNA level tended to be lower in VO. The PLB:SERCA protein ratio was significantly reduced in the VO group. Age itself did not influence the SERCA2a and PLB expression, if the hemodynamic overload was not taken into account. This study is the first to show a combined influence of volume overload and age on atrial SERCA2a expression.

Discontinuation of enfuvirtide in heavily pretreated HIV-infected individuals

BACKGROUND: Enfuvirtide was shown to be highly effective in treatment- experienced patients. Data on discontinuation of enfuvirtide and switch to new antiretroviral drugs are scarce. We aimed to evaluate the efficacy and the impact of discontinuing and/or switching enfuvirtide on virologic and clinical parameters in clinical practice. METHODS: All HIV-infected individuals participating in the Swiss HIV Cohort Study who were treated with enfuvirtide for at least 4 weeks in combination with an optimized background antiretroviral regimen were included in this study. RESULTS: A total of 151 patients were analyzed. The median baseline CD4 cell count was 108 cells/microL (interquartile range [IQR] 50-206) and HIV RNA was 4.7 log10 copies/mL (IQR 4.1-5.2). Virologic suppression, defined as a viral load below 50 copies/mL at 12 months, was achieved by 57.6% of patients. Overall, a median CD4 cell increase of 121 cells/microL (IQR 50-189) from baseline was noted. Up to 50% of patients discontinued enfuvirtide within the first year of treatment, mainly because of the patient's choice. After discontinuation of enfuvirtide, high rates of virologic failure and clinical progression were observed, notably when CD4 cell count at stopping enfuvirtide was below 100 cells/microL and no switch to new potent antiretroviral drugs such as darunavir, maraviroc, or raltegravir was performed. CONCLUSIONS: Enfuvirtide provides high virologic and immunologic response in treatment-experienced patients in the setting of clinical practice. Enfuvirtide should not be discontinued but should be replaced by new potent antiretrovirals, particularly in case of severe immunosuppression.

How reliable is an undetectable viral load?

OBJECTIVES: An article by the Swiss AIDS Commission states that patients with stably suppressed viraemia [i.e. several successive HIV-1 RNA plasma concentrations (viral loads, VL) below the limits of detection during 6 months or more of highly active antiretroviral therapy (HAART)] are unlikely to be infectious. Questions then arise: how reliable is the undetectability of the VL, given the history of measures? What factors determine reliability? METHODS: We assessed the probability (henceforth termed reliability) that the n+1 VL would exceed 50 or 1000 HIV-1 RNA copies/mL when the nth one had been <50 copies/mL in 6168 patients of the Swiss HIV Cohort Study who were continuing to take HAART between 2003 and 2007. General estimating equations were used to analyse potential factors of reliability. RESULTS: With a cut-off at 50 copies/mL, reliability was 84.5% (n=1), increasing to 94.5% (n=5). Compliance, the current type of HAART and the first antiretroviral therapy (ART) received (HAART or not) were predictive factors of reliability. With a cut-off at 1000 copies/mL, reliability was 97.5% (n=1), increasing to 99.1% (n=4). Chart review revealed that patients had stopped their treatment, admitted to major problems with compliance or were taking non-HAART ART in 72.2% of these cases. Viral escape caused by resistance was found in 5.6%. No explanation was found in the charts of 22.2% of cases. CONCLUSIONS: After several successive VLs at <50 copies/mL, reliability reaches approximately 94% with a cut-off of 50 copies/mL and approximately 99% with a cut-off at 1000 copies/mL. Compliance is the most important factor predicting reliability.

REVERSIBLE SUPPRESSION OF NITRIC OXIDE SYSTEM IN ESSENTIAL HYPERTENSION

Despite enormous research in the field of hypertension, its pathophysiology still remains largely unresolved and appears to be multifactorial. In the present communication, we have analyzed the status of nitric oxide (NO) in the patients with essential hypertension and age matched controls. We have found that the levels of NO are lowered in essential hypertension. The normalization of blood pressure by administration of antihypertensive therapy causes rise in the NO level indicating that perturbed NO status in essential hypertension is reversible. Addition of antioxidant to the antihypertensive drugs causes a further, though non significant, rise in the levels of NO, suggesting that antioxidants may be combined with antihypertensive drugs as adjunct in the management of essential hypertension.