Effect of the sphingosine kinase 1 selective inhibitor, PF-543 on arterial and cardiac remodeling in a hypoxic model of pulmonary arterial hypertension

Recent studies have demonstrated that the expression of sphingosine kinase 1, the enzyme that catalyses formation of the bioactive lipid, sphingosine 1-phosphate, is increased in lungs from patients with pulmonary arterial hypertension. In addition, Sk1-/- mice are protected from hypoxic-induced pulmonary arterial hypertension. Therefore, we assessed the effect of the sphingosine kinase 1 selective inhibitor, PF-543 and a sphingosine kinase 1/ceramide synthase inhibitor, RB-005 on pulmonary and cardiac remodeling in a mouse hypoxic model of pulmonary arterial hypertension. Administration of the potent sphingosine kinase 1 inhibitor, PF-543 in a mouse hypoxic model of pulmonary hypertension had no effect on vascular remodeling but reduced right ventricular hypertrophy. The latter was associated with a significant reduction in cardiomyocyte death. The protection involves a reduction in the expression of p53 (that promotes cardiomyocyte death) and an increase in the expression of anti-oxidant nuclear factor (erythroid-derived 2)-like 2 (Nrf-2). In contrast, RB-005 lacked effects on right ventricular hypertrophy, suggesting that SK1 inhibition might be nullified by concurrent inhibition of ceramide synthase. Therefore, our findings with PF-543 suggest an important role for SK1 in the development of hypertrophy in PAH

Measuring health and broader well-being benefits in the context of opiate dependence: the psychometric performance of the ICECAP-A and the EQ-5D-5L

Background Measuring outcomes in economic evaluations of social care interventions is challenging because both health and well-being benefits are evident. The ICEpop CAPability instrument for adults (ICECAP-A) and the five-level EuroQol five-dimensional questionnaire (EQ-5D-5L) are measures potentially suitable for the economic evaluation of treatments for substance use disorders. Evidence for their validity in this context is, however, lacking. Objectives To assess the construct validity of the ICECAP-A and the EQ-5D-5L in terms of convergent and discriminative validity and sensitivity to change on the basis of standard clinical measures (Clinical Outcomes in Routine Evaluation-Outcome Measure, Treatment Outcomes Profile, Interpersonal Support Evaluation List, Leeds Dependence Questionnaire, and Social Satisfaction Questionnaire). Methods A secondary analysis of pilot trial data for heroin users in opiate substitution treatment was conducted. Baseline convergence with clinical measures was assessed using the Pearson correlation coefficient. Discriminative validity was assessed using one-way analysis of variance and stepwise regressions. Sensitivity to changes in clinical indicators was assessed at 3 and 12 months using the standardized response mean statistic and parametric and nonparametric testing. Results Both measures had the same level of construct validity, except for clinical indicators of well-being, for which the ICECAP-A performed better. The ICECAP-A was sensitive to changes in both health and well-being indicators. The EQ-5D-5L had lower levels of sensitivity to change, and a ceiling effect (27%), particularly evident in the dimensions of self-care (89%), mobility (75%), and usual activities (72%). Conclusions The findings support the construct validity of both measures, but the ICECAP-A gives more attention to broader impacts and is more sensitive to change. The ICECAP-A shows promise in evaluating treatments for substance use disorders for which recovery is the desired outcome

Bacterial killing by complement requires membrane attack complex formation via surface-bound C5 convertases

The immune system kills bacteria by the formation of lytic membrane attack complexes (MACs), triggered when complement enzymes cleave C5. At present, it is not understood how the MAC perturbs the composite cell envelope of Gram-negative bacteria. Here, we show that the role of C5 convertase enzymes in MAC assembly extends beyond the cleavage of C5 into the MAC precursor C5b. Although purified MAC complexes generated from preassembled C5b6 perforate artificial lipid membranes and mammalian cells, these components lack bactericidal activity. In order to permeabilize both the bacterial outer and inner membrane and thus kill a bacterium, MACs need to be assembled locally by the C5 convertase enzymes. Our data indicate that C5b6 rapidly loses the capacity to form bactericidal pores; therefore, bacterial killing requires both in situ conversion of C5 and immediate insertion of C5b67 into the membrane. Using flow cytometry and atomic force microscopy, we show that local assembly of C5b6 at the bacterial surface is required for the efficient insertion of MAC pores into bacterial membranes. These studies provide basic molecular insights into MAC assembly and bacterial killing by the immune system

A roadmap for gene system development in Clostridium

Clostridium species are both heroes and villains. Some cause serious human and animal diseases, those present in the microbiota contribute to health and wellbeing, while others represent useful industrial chassis for the production of chemicals and fuels. To understand, counter or exploit, there is a fundamental requirement for effective systems that may be used for directed or random genome modifications. We have formulated a simple roadmap whereby the necessary gene systems maybe developed and deployed. At its heart is the use of 'pseudo-suicide' vectors and the creation of a pyrE mutant (a uracil auxotroph), initially aided by ClosTron technology, but ultimately made using a special form of allelic exchange termed ACE (Allele-Coupled Exchange). All mutants, regardless of the mutagen employed, are made in this host. This is because through the use of ACE vectors, mutants can be rapidly complemented concomitant with correction of the pyrE allele and restoration of uracil prototrophy. This avoids the phenotypic effects frequently observed with high copy number plasmids and dispenses with the need to add antibiotic to ensure plasmid retention. Once available, the pyrE host may be used to stably insert all manner of application specific modules. Examples include, a sigma factor to allow deployment of a mariner transposon, hydrolases involved in biomass deconstruction and therapeutic genes in cancer delivery vehicles. To date, provided DNA transfer is obtained, we have not encountered any clostridial species where this technology cannot be applied. These include, Clostridium difficile, Clostridium acetobutylicum, Clostridium beijerinckii, Clostridium botulinum, Clostridium perfringens, Clostridium sporogenes, Clostridium pasteurianum, Clostridium ljungdahlii, Clostridium autoethanogenum and even Geobacillus thermoglucosidasius

Plasma sphingosine-1-phosphate is elevated in obesity

Background: Dysfunctional lipid metabolism is a hallmark of obesity and insulin resistance and a risk factor for various cardiovascular and metabolic complications. In addition to the well known increase in plasma triglycerides and free fatty acids, recent work in humans and rodents has shown that obesity is associated with elevations in the bioactive class of sphingolipids known as ceramides. However, in obesity little is known about the plasma concentrations of sphinogsine-1-phosphate (S1P), the breakdown product of ceramide, which is an important signaling molecule in mammalian biology. Therefore, the purpose of this study was to examine the impact of obesity on circulating S1P concentration and its relationship with markers of glucose metabolism and insulin sensitivity. Methodology/Principal Findings: Plasma S1P levels were determined in high-fat diet (HFD)-induced and genetically obese (ob/ob) mice along with obese humans. Circulating S1P was elevated in both obese mouse models and in obese humans compared with lean healthy controls. Furthermore, in humans, plasma S1P positively correlated with total body fat percentage, body mass index (BMI), waist circumference, fasting insulin, HOMA-IR, HbA1c (%), total and LDL cholesterol. In addition, fasting increased plasma S1P levels in lean healthy mice. Conclusion: We show that elevations in plasma S1P are a feature of both human and rodent obesity and correlate with metabolic abnormalities such as adiposity and insulin resistance

The Regulation and Expression of the Creatine Transporter: A Brief Review of Creatine Supplementation in Humans and Animals

Creatine monohydrate has become one of the most popular ergogenic sport supplements used today. It is a nonessential dietary compound that is both endogenously synthesized and naturally ingested through diet. Creatine ingested through supplementation has been observed to be absorbed into the muscle exclusively by means of a creatine transporter, CreaT1. The major rationale of creatine supplementation is to maximize the increase within the intracellular pool of total creatine (creatine + phosphocreatine). There is much evidence indicating that creatine supplementation can improve athletic performance and cellular bioenergetics, although variability does exist. It is hypothesized that this variability is due to the process that controls both the influx and efflux of creatine across the cell membrane, and is likely due to a decrease in activity of the creatine transporter from various compounding factors. Furthermore, additional data suggests that an individual's initial biological profile may partially determine the efficacy of a creatine supplementation protocol. This brief review will examine both animal and human research in relation to the regulation and expression of the creatine transporter (CreaT). The current literature is very preliminary in regards to examining how creatine supplementation affects CreaT expression while concomitantly following a resistance training regimen. In conclusion, it is prudent that future research begin to examine CreaT expression due to creatine supplementation in humans in much the same way as in animal models

Modeling flow cytometry data for cancer vaccine immune monitoring

Flow cytometry (FCM) is widely used in cancer research for diagnosis, detection of minimal residual disease, as well as immune monitoring and profiling following immunotherapy. In all these applications, the challenge is to detect extremely rare cell subsets while avoiding spurious positive events. To achieve this objective, it helps to be able to analyze FCM data using multiple markers simultaneously, since the additional information provided often helps to minimize the number of false positive and false negative events, hence increasing both sensitivity and specificity. However, with manual gating, at most two markers can be examined in a single dot plot, and a sequential strategy is often used. As the sequential strategy discards events that fall outside preceding gates at each stage, the effectiveness of the strategy is difficult to evaluate without laborious and painstaking back-gating. Model-based analysis is a promising computational technique that works using information from all marker dimensions simultaneously, and offers an alternative approach to flow analysis that can usefully complement manual gating in the design of optimal gating strategies. Results from model-based analysis will be illustrated with examples from FCM assays commonly used in cancer immunotherapy laboratories

The influence of alkalosis on repeated high-intensity exercise performance and acid–base balance recovery in acute moderate hypoxic conditions

Purpose Exacerbated hydrogen cation (H⁺) production is suggested to be a key determinant of fatigue in acute hypoxic conditions. This study, therefore, investigated the effects of NaHCO3 ingestion on repeated 4 km TT cycling performance and post-exercise acid–base balance recovery in acute moderate hypoxic conditions. Methods Ten male trained cyclists completed four repeats of 2 × 4 km cycling time trials (TT1 and TT2) with 40 min passive recovery, each on different days. Each TT series was preceded by supplementation of one of the 0.2 g kg⁻¹ BM NaHCO3 (SBC2), 0.3 g kg⁻¹ BM NaHCO3 (SBC3), or a taste-matched placebo (0.07 g kg⁻¹ BM sodium chloride; PLA), administered in a randomized order. Supplements were administered at a pre-determined individual time to peak capillary blood bicarbonate concentration ([HCO3⁻]). Each TT series was also completed in a normobaric hypoxic chamber set at 14.5% FiO2 (~ 3000 m). Results Performance was improved following SBC3 in both TT1 (400.2 ± 24.1 vs. 405.9 ± 26.0 s; p = 0.03) and TT2 (407.2 ± 29.2 vs. 413.2 ± 30.8 s; p = 0.01) compared to PLA, displaying a very likely benefit in each bout. Compared to SBC2, a likely and possible benefit was also observed following SBC3 in TT1 (402.3 ± 26.5 s; p = 0.15) and TT2 (410.3 ± 30.8 s; p = 0.44), respectively. One participant displayed an ergolytic effect following SBC3, likely because of severe gastrointestinal discomfort, as SBC2 still provided ergogenic effects. Conclusion NaHCO3 ingestion improves repeated exercise performance in acute hypoxic conditions, although the optimal dose is likely to be 0.3 g kg⁻¹ BM

Collaborative care for depression and anxiety problems

This review is published as a Cochrane Review in the Cochrane Database of Systematic Reviews 2012, Issue 10. Cochrane Reviews are regularly updated as new evidence emerges and in response to comments and criticisms, and the Cochrane Database of Systematic Reviews should be consulted for the most recent version of the Review.Common mental health problems, such as depression and anxiety, are estimated to affect up to 15% of the UK population at any one time, and health care systems worldwide need to implement interventions to reduce the impact and burden of these conditions. Collaborative care is a complex intervention based on chronic disease management models that may be effective in the management of these common mental health problems