The gene order in the nuo-operon is not essential for the assembly of E. coli complex I.

Energy-converting NADH: ubiquinone oxidoreductase, respiratory complex I, plays an important role in cellular energy metabolism. Bacterial complex I is generally composed of 14 different subunits, seven of which are membranous and the other seven are globular proteins. They are encoded by the nuo-operon, whose gene order is strictly conserved in bacteria. The operon starts with nuoA encoding a membranous subunit followed by genes encoding globular subunits. To test the idea that NuoA acts as a seed to initiate the assembly of the complex in the membrane, we generated mutants that either lacked nuoA or contain nuoA at a different position within the operon. To enable the detection of putative assembly intermediates, the globular subunit NuoF and the membranous subunit NuoM were individually decorated with the fluorescent protein mCherry. Deletion of nuoA led to the assembly of an inactive complex in the membrane containing NuoF and NuoM. Re-arrangement of nuoA within the nuo-operon led to a slightly diminished amount of complex I in the membrane that was fully active. Thus, nuoA but not its distinct position in the operon is required for the assembly of E. coli complex I. Furthermore, we detected a previously unknown assembly intermediate in the membrane containing NuoM that is present in greater amounts than complex I.

HIV-1 infection and the lack of viral control are associated with greater expression of interleukin-21 receptor on CD8+ T cells.

OBJECTIVES: Interleukin-21 (IL-21) has been linked with the generation of virus-specific memory CD8+ T cells following acute infection with HIV-1 and reduced exhaustion of CD8+ T cells. IL-21 has also been implicated in the promotion of CD8+ T-cell effector functions during viral infection. Little is known about the expression of interleukin-21 receptor (IL-21R) during HIV-1 infection or its role in HIV-1-specific CD8+ T-cell maintenance and subsequent viral control. METHODS: We compared levels of IL-21R expression on total and memory subsets of CD8+ T cells from HIV-1-negative and HIV-1-positive donors. We also measured IL-21R on antigen-specific CD8+ T cells in volunteers who were positive for HIV-1 and had cytomegalovirus-responding T cells. Finally, we quantified plasma IL-21 in treatment-naive HIV-1-positive individuals and compared this with IL-21R expression. RESULTS: IL-21R expression was significantly higher on CD8+ T cells (P = 0.0256), and on central memory (P = 0.0055) and effector memory (P = 0.0487) CD8+ T-cell subsets from HIV-1-positive individuals relative to HIV-1-negative individuals. For those infected with HIV-1, the levels of IL-21R expression on HIV-1-specific CD8+ T cells correlated significantly with visit viral load (r = 0.6667, P = 0.0152, n = 13) and inversely correlated with plasma IL-21 (r = -0.6273, P = 0.0440, n = 11). Lastly, CD8+ T cells from individuals with lower set point viral load who demonstrated better viral control had the lowest levels of IL-21R expression and highest levels of plasma IL-21. CONCLUSION: Our data demonstrates significant associations between IL-21R expression on peripheral CD8+ T cells and viral load, as well as disease trajectory. This suggests that the IL-21 receptor could be a novel marker of CD8+ T-cell dysfunction during HIV-1 infection.

Role of the sympathetic nervous system in cardiometabolic control: implications for targeted multiorgan neuromodulation approaches.

Sympathetic overdrive plays a key role in the perturbation of cardiometabolic homeostasis. Diet-induced and exercise-induced weight loss remains a key strategy to combat metabolic disorders, but is often difficult to achieve. Current pharmacological approaches result in variable responses in different patient cohorts and long-term efficacy may be limited by medication intolerance and nonadherence. A clinical need exists for complementary therapies to curb the burden of cardiometabolic diseases. One such approach may include interventional sympathetic neuromodulation of organs relevant to cardiometabolic control. The experience from catheter-based renal denervation studies clearly demonstrates the feasibility, safety and efficacy of such an approach. In analogy, denervation of the common hepatic artery is now feasible in humans and may prove to be similarly useful in modulating sympathetic overdrive directed towards the liver, pancreas and duodenum. Such a targeted multiorgan neuromodulation strategy may beneficially influence multiple aspects of the cardiometabolic disease continuum offering a holistic approach.

The Effects of Water-based Exercise Training in People with Type 2 Diabetes.

PURPOSE: To investigate the effects of 8 wk of upright water-based exercise training in people with type 2 diabetes. METHODS: Thirteen participants with type 2 diabetes (54% male; 60.9 ± 9.6 yr, mean ± standard deviation) completed 8 wk of upright water-based exercise training at a moderate intensity (60%-80% of exercise test-derived maximum HR), for 1 h, three times a week (TG). Fourteen participants (64% male; 63.9 ± 9.8 yr) acted as a control group (CG) who maintained their usual activities. Preintervention and postintervention, participants performed cardiopulmonary exercise testing to determine V˙O2peak and one-repetition maximum testing to assess muscular strength. Blood profiles were assessed with standard assays. Body mass index and waist/hip ratio were employed as measures of anthropometry. Endothelium-dependent (brachial artery flow-mediated dilation) and independent (glyceryl trinitrate-mediated) function were assessed using vascular ultrasound. RESULTS: Water-based training increased V˙O2peak (18.5 ± 4.3 mL·kg·min to 21.5 ± 5.4 mL·kg·min) (P = 0.002), overall muscle strength (123 ± 44 kg to 139 ± 43 kg) and leg strength (92 ± 28 kg to 104 ± 29 kg), compared with the CG (P = 0.001). The effect on pectoral strength (31 ± 17 kg to 35 ± 16 kg) was not significantly different to the CG (24 ± 12 kg to 26 ± 14 kg) (P = 0.08). No change was observed in anthropometry, blood profiles, or glyceryl trinitrate-mediated vascular function. Flow-mediated dilation was increased after training (6.1% ± 2.4% to 6.5% ± 3.0%), compared with controls who demonstrated a slight decrease (6.2% ± 1.6% to 5.4% ± 1.6%) (P = 0.002). CONCLUSIONS: Water-based circuit training was well tolerated and appears to be an effective exercise modality for improving aerobic fitness, strength, and vascular function in people with type 2 diabetes.

Nature of Cardiac Rehabilitation Around the Globe.

BACKGROUND: Cardiac rehabilitation (CR) is a clinically-effective but complex model of care. The purpose of this study was to characterize the nature of CR programs around the world, in relation to guideline recommendations, and compare this by World Health Organization (WHO) region. METHODS: In this cross-sectional study, a piloted survey was administered online to CR programs globally. Cardiac associations and local champions facilitated program identification. Quality (benchmark of ≥ 75% of programs in a given country meeting each of 20 indicators) was ranked. Results were compared by WHO region using generalized linear mixed models. FINDINGS: 111/203 (54.7%) countries in the world offer CR; data were collected in 93 (83.8%; N = 1082 surveys, 32.1% program response rate). The most commonly-accepted indications were: myocardial infarction (n = 832, 97.4%), percutaneous coronary intervention (n = 820, 96.1%; 0.10), and coronary artery bypass surgery (n = 817, 95.8%). Most programs were led by physicians (n = 680; 69.1%). The most common CR providers (mean = 5.9 ±â€¯2.8/program) were: nurses (n = 816, 88.1%; low in Africa, p < 0.001), dietitians (n = 739, 80.2%), and physiotherapists (n = 733, 79.3%). The most commonly-offered core components (mean = 8.7 ±â€¯1.9 program) were: initial assessment (n = 939, 98.8%; most commonly for hypertension, tobacco, and physical inactivity), risk factor management (n = 928, 98.2%), patient education (n = 895, 96.9%), and exercise (n = 898, 94.3%; lower in Western Pacific, p < 0.01). All regions met ≥ 16/20 quality indicators, but quality was < 75% for tobacco cessation and return-to-work counseling (lower in Americas, p = < 0.05). INTERPRETATION: This first-ever survey of CR around the globe suggests CR quality is high. However, there is significant regional variation, which could impact patient outcomes.

Evaluation of national guidelines for bronchiolitis: AGREEments and controversies.

AIM: Bronchiolitis is a common respiratory illness and is a leading cause of hospitalisation in infancy. We aimed to appraise three recent national bronchiolitis guidelines produced by the Australasian Paediatric Research in Emergency Departments International Collaborative, the National Institute for Health and Care Excellence in the UK and the American Academy of Pediatrics. METHODS: A group of final-year medical students and one senior clinician used the AGREE II tool to appraise each guideline in two stages. First, two students appraised each guideline independently and presented their results. Second, two self-selected students met with the senior clinicians to review all scores to ensure completeness of the appraisal and consistency of AGREE II application. RESULTS: The guidelines scored well overall, with particular strengths in the domains of clarity of presentation, scope and purpose and rigour of development. Comparison of the recommendations across each guideline demonstrated a high degree of consistency. Notable differences included recommendations for the role of palivizumab in prevention of bronchiolitis, the use of continuous pulse oximetry monitoring in the hospitalised patient and the value of respiratory virus testing. CONCLUSIONS: Our appraisal of bronchiolitis guidelines from three high-income countries demonstrated that they were of high quality, with substantial areas of agreement. Most aspects of clinical practice should be uniform for this common paediatric condition. Areas of guideline weakness were in the domains of applicability and editorial independence. We identified three areas of controversy where further research is needed to support stronger evidence-based recommendations.

Predation scars may influence host susceptibility to pathogens: evaluating the role of corallivores as vectors of coral disease.

Infectious diseases not regulated by host density, such as vector-borne diseases, have the potential to drive population declines and extinctions. Here we test the vector potential of the snail Drupella sp. and butterflyfish Chaetodon plebeius for two coral diseases, black band (BBD) and brown band (BrB) disease. Drupella transmitted BrB to healthy corals in 40% of cases immediately following feeding on infected corals, and even in 12% of cases 12 and 24 hours following feeding. However, Drupella was unable to transmit BBD in either transmission treatment. In a field experiment testing the vector potential of naturally-occurring fish assemblages, equivalent numbers of caged and uncaged coral fragments became infected with either BrB, BBD or skeletal eroding band, indicating that corallivorous fish were unlikely to have caused transmission. In aquaria, C. plebeius did not transmit either BBD or BrB, even following extended feeding on both infected and healthy nubbins. A literature review confirmed only four known coral disease vectors, all invertebrates, corroborating our conclusion that polyp-feeding fishes are unlikely to be vectors of coral diseases. This potentially because polyp-feeding fishes produce shallow lesions, not allowing pathogens to invade coral tissues. In contrast, corallivorous invertebrates that create deeper feeding scars increase pathogens transmission.

Body fat composition impacts the hematologic toxicities and pharmacokinetics of doxorubicin in Asian breast cancer patients.

Body surface area (BSA)-based dosing leads to wide inter-individual variations in drug pharmacokinetics and pharmacodynamics, whereas body composition has been shown to be a more robust determinant of efficacy and toxicity of certain chemotherapeutic agents. We correlated various parameters of body composition with doxorubicin pharmacokinetics and hematologic toxicities in Asian patients with locally advanced or metastatic breast cancer. Our analysis included 84 patients from two studies who received pre- or post-operative single-agent doxorubicin; pharmacokinetic parameters were available for 44 patients. Body composition parameters were derived from CT cross-sectional images and population pharmacokinetic analysis was conducted using mixed-effects modeling. Higher intra-abdominal fat volume and fat ratio (intra-abdominal:total abdominal fat volume) correlated with greater incidence of grade 4 leukopenia on cycle 1 day 15 (mean intra-abdominal fat volume: 97.4 ± 46.5 cm(3) vs 63.4 ± 30.9 cm(3), p = 0.014; mean fat ratio: 0.43 ± 0.11 vs 0.33 ± 0.09, p = 0.012, grade 4 vs grade 0-3 leukopenia). On subset analysis, this relationship was maintained even in underweight patients. Concordantly, there were positive correlations between doxorubicin AUC and intra-abdominal fat volume as well as total abdominal fat volume (r (2) = 0.324 and 0.262, respectively, all p < 0.001). BSA and muscle volume did not predict for doxorubicin pharmacokinetics or toxicities. High-intra-abdominal fat volume but not BSA predicted for greater doxorubicin exposure and hematologic toxicities, suggesting that body composition is superior to BSA in determining doxorubicin pharmacokinetics and pharmacodynamics. Body composition has an emerging role in chemotherapy dose determination.

Identification of a molecular signature unique to metal-reducing Gammaproteobacteria.

Functional genes required for microbial (dissimilatory) metal reduction display high sequence divergence, which limits their utility as molecular biomarkers for tracking the presence and activity of metal-reducing bacteria in natural and engineered systems. In the present study, homologs of the outer membrane beta-barrel protein MtrB of metal-reducing Gammaproteobacteria were found to contain a unique N-terminal CXXC motif that was missing from MtrB homologs of nonmetal-reducing Gammaproteobacteria and metal- and nonmetal-reducing bacteria outside the Gammaproteobacteria. To determine whether the N-terminal CXXC motif of MtrB was required for dissimilatory metal reduction, each cysteine in the CXXC motif of the representative metal-reducing gammaproteobacterium Shewanella oneidensis was replaced with alanine, and the resulting site-directed mutants were tested for metal reduction activity. Anaerobic growth experiments demonstrated that the first, but not the second, conserved cysteine was required for metal reduction by S. oneidensis. The ability to predict metal reduction by Gammaproteobacteria with unknown metal reduction capability was confirmed with Vibrio parahaemolyticus, a pathogen whose genome encodes an MtrB homolog with an N-terminal CXXC motif. MtrB homologs with an N-terminal CXXC motif may thus represent a molecular signature unique to metal-reducing members of the Gammaproteobacteria.

Population pharmacokinetics and pharmacogenetics of alcohol in Chinese and Indians in Singapore.

WHAT IS KNOWN AND OBJECTIVE:   Interindividual variability in alcohol pharmacokinetics is influenced by a number of factors, including polymorphisms in genes mediating alcohol pharmacology, ethnicity, sex and body size. Several studies have evaluated the population pharmacokinetics of alcohol from breath alcohol measures. None of these studies, however, have evaluated ethnicity and alcohol-metabolizing enzyme genotypes as covariates in their population pharmacokinetic modelling. We aimed to develop a population pharmacokinetic model using clinical and genetic factors and to identify covariates that influenced interindividual variability in alcohol clearance and volume of distribution. METHODS:   Hundred and eighty healthy subjects (90 Chinese and 90 Indians; 45 males and 45 females from each ethnic group) ingested a vodka-orange juice mixture to simulate social drinking. Subjects were genotyped for the ADH1B (Arg48His), ALDH2 (Glu504Lys) and CYP2E1 (c.-1293G>C and c.-1053C>T) polymorphisms. A base pharmacokinetic model was developed using the nonmem software (NONMEM Project Group, University of California, San Francisco, San Francisco, CA, USA) to determine the alcohol clearance and volume of distribution. The model was extended to include covariates that influenced the between-subject variability. RESULTS AND DISCUSSION:   Body weight and sex significantly influenced absorption rate and volume of distribution of alcohol. Body weight and ADH1B Arg48His polymorphism significantly influenced alcohol clearance. The Michaelis-Menten elimination rate (Vmax ) was decreased by 10% in homozygous ADH1B*1/*1 subjects. Ethnicity was not determined to be a significant covariate in the final population pharmacokinetic model. WHAT IS NEW AND CONCLUSION:   Gender and body weight were covariates that contributed most to explaining the observed interindividual alcohol pharmacokinetic variability. Of the four SNPs examined in this study, only ADH1B Arg48His polymorphism had a significant, though modest, effect on the pharmacokinetics of alcohol.

Life-threatening hypokalaemia associated with ibuprofen-induced renal tubular acidosis.

Renal tubular acidosis is an underreported complication of ibuprofen misuse, and can result in life-threatening hypokalaemia. We describe four patients who presented with profound hypokalaemia and muscle weakness associated with excessive ibuprofen ingestion. Ibuprofen cessation and supportive management resulted in complete biochemical resolution within a few days. These cases remind practitioners about potential complications of unmonitored use of over-the-counter analgesics, including those with potential for misuse due to their codeine content.

Concomitant atherosclerotic disease detected by whole-body MR angiography in relation to coronary artery calcification in patients with coronary artery disease.

PURPOSE: Patients with coronary artery disease (CAD) show a high prevalence for concomitant atherosclerotic peripheral arterial disease (PAD). On the other hand, PAD seems to be an additional risk factor for cardiac events. We evaluated the correlation between arterial pathologies as found in whole-body MR angiography and coronary artery calcification (CAC) detected by electron beam computed tomography (EBCT) and multislice CT (MSCT). MATERIALS AND METHODS: Two hundred and twenty-eight patients (161 men; 67 women) with suspicion for CAD/known CAD underwent whole-body contrast-enhanced MR angiography (wb-ce-MRA) and EBCT/MSCT. An atherosclerosis index was calculated for each patient Index = (40)Sigma(n=1) w(i) with w(i) being the grading of the stenosis of the i (ten) of 40 arteria segments (grade: 0 - no plaque; 1 - plaque - < or = 50 % stenosis; 2 - > 50 % stenosis - < or = 90 % stenosis; 3 - > 90 % stenosis - < 100 % stenosis; 4 - occlusion). Correlations between CAC and atherosclerosis index were performed. RESULTS: Wb-ce MRA and CAC correlate only moderately in this population. An atherosclerosis index 8 renders a positive predictive value for a CAC 100 of 63.3 %. CONCLUSION: An atherosclerosis index as defined in this study does not fully correlate with the extent of CAD as revealed by catheter angiography or EBCT/MSCT, but it might theoretically mirror the increased risk by PAD. It thus might be a promising complementary parameter for the prediction of cardiac events. Future studies need to show its possible additional predictive impact.

Population pharmacokinetics of caffeine in healthy male adults using mixed-effects models.

OBJECTIVE: Caffeine has been shown to maintain or improve the performance of individuals, but its pharmacokinetic profile for Asians has not been well characterized. In this study, a population pharmacokinetic model for describing the pharmacokinetics of caffeine in Singapore males was developed. The data were also analysed using non-compartmental models. METHODS: Data gathered from 59 male volunteers, who each ingested a single caffeine capsule in two clinical trials (3 or 5 mg/kg), were analysed via non-linear mixed-effects modelling. The participants' covariates, including age, body weight, and regularity of caffeinated-beverage consumption or smoking, were analysed in a stepwise fashion to identify their potential influence on caffeine pharmacokinetics. The final pharmacostatistical model was then subjected to stochastic simulation to predict the plasma concentrations of caffeine after oral (204, 340 and 476 mg) dosing regimens (repeated dosing every 6, 8 or 12 h) over a hypothetical 3-day period. RESULTS: The data were best described by a one-compartmental model with first-order absorption and first-order elimination. Smoking status was an influential covariate for clearance: clearance (mL/min) = 110*SMOKE + 114, where SMOKE was 0 and 1 for the non-smoker and the smoker respectively. Interoccasion variability was smaller compared to interindividual variability in clearance, volume and absorption rate (27% vs. 33%, 10% vs. 15% and 23% vs. 51% respectively). The extrapolated elimination half-lives of caffeine in the non-smokers and the smokers were 4.3 +/- 1.5 and 3.0 +/- 0.7 h respectively. Dosing simulations indicated that dosing regimens of 340 mg (repeated every 8 h) and 476 mg (repeated every 6 h) should achieve population-averaged caffeine concentrations within the reported beneficial range (4.5-9 microg/mL) in the non-smokers and the smokers respectively over 72 h. CONCLUSION: The population pharmacokinetic model satisfactorily described the disposition and variability of caffeine in the data. Mixed-effects modelling showed that the dose of caffeine depended on cigarette smoking status.

Proinflammatory markers, insulin sensitivity, and cardiometabolic risk factors in treated HIV infection.

Treated HIV infection and HIV-lipoatrophy increases risk of cardiovascular disease (CVD) and type 2 diabetes mellitus (T2DM). Circulating inflammatory molecules may, in part, explain this increased risk. This study examined circulating inflammatory molecules in treated HIV infection in relation to insulin sensitivity, lipids total body, and intramyocellular fat, compared to insulin-resistant obesity (an index group at high risk of diabetes). Detailed metabolic phenotypes were measured in 20 treated HIV-infected men (with and without subcutaneous lipoatrophy) vs. 26 insulin-resistant obese men (IR-O, n = 26), including inflammatory molecules, insulin sensitivity, total body fat (TBF), visceral fat (visceral adipose tissue (VAT)), and intramyocellular lipid (IMCL). C-reactive protein (CRP) levels in treated HIV were similar to those in IR-O, despite lower TBF and greater insulin sensitivity in treated HIV. In HIV-lipoatrophy, CRP was higher than that found in IR-O. Adiponectin was similar between treated HIV and IR-O, but significantly lower in those with HIV-lipoatrophy. In treated HIV, subjects with higher CRP had significantly higher total cholesterol, VAT, and IMCL. In treated HIV, subjects with lower adiponectin had significantly lower HDL and higher triglycerides, glucose, VAT, and IMCL. In conclusion, a proinflammatory milieu equivalent to that of insulin-resistant obesity characterizes lean men with treated HIV infection, worse in those with subcutaneous lipoatrophy. These factors may contribute to the accelerated diabetogenesis and cardiac risk observed in treated HIV infection.

Anti-emetic effect of high-dose metoclopramide vs alizapride--a randomised crossover study.

A randomised double-blind crossover study was undertaken to compare the anti-emetic efficacy of alizapride against high dose metoclopramide. A total of 32 patients on cisplatin were randomised to receive either high dose metoclopramide (7 mg kg-1 day-1) or alizapride (5 mg kg-1 day-1). Anti-emetic responses in terms of control of vomiting episodes were similar in both regimens (59%). However, patients showed a statistically significant preference for high dose metoclopramide (P = 0.02). Side effects of both regimens were minimal. We conclude that alizapride is not superior to high dose metoclopramide in controlling cisplatin induced vomiting.

Development of angiotensin converting enzyme in fetal lung and placenta of the rat and human.

Angiotensin converting enzyme (ACE) activity in fetal lung and placenta was determined by the method of Cushman and Cheung (1971) during the second trimester of human pregnancy and throughout the rat gestation. The enzyme activity in the neonatal rat lung was also determined during the first 19 days of life. The enzyme activity in both tissues of both species increased with gestation. The activity in human fetal lung at the end of the second trimester was already 70% of that present in the adult human lung while rat fetal lung enzyme activity at term was only 15% of the adult value. The activity in the term placenta of the human and rat was respectively 13% and 5% that of the adult lung value. Developmental increases in enzyme activity continued in the neonatal rat lung till adult value at about 19 days postpartum. The pattern of fetal lung enzyme development in the rat resembled that of the rabbit fetal lung as determined by other investigators using different techniques but was different from that of the human. The findings support the suggestion that ACE in the lung and placenta play important roles in the maintenance of circulatory homeostasis during the latter part of gestation, at birth and early postpartum, albeit at a different extent in different species.

Some laws relating to population growth: laws directly affecting fertility.

PIP: In Singapore the government policy is to convince as many of its population as possible to adopt the value of the 2-child family. Contraception is recognized as the primary way to reach this goal. Sterilization is considered a supplementary measure, with abortion the more extreme final alternative. As might be expected from the government policy, there is no legal restriction on the individual who wishes to practice contraception. However, persons or associations involved in the promotion or dissemination of family planning information or sale or distribution of family planning methods need to register with the Family Planning and Population Board (FPPB) and be subject to the Board's direction. In 1974, when the sterilization law was further liberalized, Parliament passed the Abortion Act 1974, effective December 27, 1974. This Act replaced the original Abortion Act and provided for abortion on demand subject to certain safeguards. It is required that the abortion be performed by a registered medical practitioner acting on the request of a pregnant woman and with her written consent. The 1 important safeguard laid down by the Act is that no termination of pregnancy shall be carried out if the pregnancy exceeds 24 weeks unless the abortion is immediately necessary to save the life or to prevent grave permanent injury to the physical or mental health of the pregnant woman. Currently, the government policy in regard to sterilization is to encourage sterilization on the part of both men and women as an effective way of limiting the size of families to 2 children. A number of incentives have been made available to persuade people to undergo sterilization.^ieng

Psychological effects of abortion (a study of 1739 cases).

PIP: A 6-month prospective study was conducted among 1739 women who underwent therapeutic abortion at Kandang Kerbau Hospital in Singapore to ascertain the aftereffects of abortion. Results of the study indicate that induced abortion has no observable bad effects on the mental health of the patients. In fact, somatic and psychiatric complaints were reduced and sexual adjustment increased 6 months postoperative. Those who were also sterilized at the time of the abortion showed a slightly lower rate of somatic symptom reduction than the rest of the group.^ieng