Predicted hexameric structure of the Agrobacterium VirB4 C terminus suggests VirB4 acts as a docking site during type IV secretion

The Agrobacterium T-DNA transporter belongs to a growing class of evolutionarily conserved transporters, called type IV secretion systems (T4SSs). VirB4, 789 aa, is the largest T4SS component, providing a rich source of possible structural domains. Here, we use a variety of bioinformatics methods to predict that the C-terminal domain of VirB4 (including the Walker A and B nucleotide-binding motifs) is related by divergent evolution to the cytoplasmic domain of TrwB, the coupling protein required for conjugative transfer of plasmid R388 from Escherichia coli. This prediction is supported by detailed sequence and structure analyses showing conservation of functionally and structurally important residues between VirB4 and TrwB. The availability of a solved crystal structure for TrwB enables the construction of a comparative model for VirB4 and the prediction that, like TrwB, VirB4 forms a hexamer. These results lead to a model in which VirB4 acts as a docking site at the entrance of the T4SS channel and acts in concert with VirD4 and VirB11 to transport substrates (T-strand linked to VirD2 or proteins such as VirE2, VirE3, or VirF) through the T4SS.     

HIV incidence, retention rate, and baseline predictors of HIV incidence and retention in a prospective cohort study of injection drug users in Xinjiang, China.

OBJECTIVE: To determine HIV seroincidence, study participant retention rate, and baseline predictors of HIV incidence and study retention among high-risk injection drug users (IDUs) in Xinjiang, China. METHODS: A total of 508 eligible seronegative high-risk IDUs were enrolled. Study participants were tested for HIV-1 and counseled at the baseline, 6-month, and 12-month follow-up visits. Sociodemographic and behavioral data were collected during each study visit. The HIV-1 incidence rate and the retention rate were analyzed as a function of sociodemographic, behavioral, and recruitment variables. RESULTS: At 12 months of follow-up, the HIV-1 incidence rate was 8.8 per 100 person-years (95% CI 6.3-12.0%) and the participant retention rate was 93%. Marital status at baseline was the only predictor of HIV incidence. No baseline variables were predictive of study retention. CONCLUSIONS: HIV incidence is high among IDUs in Xinjiang, China. Baseline predictors of incidence and retention were minimal. The participant retention rate in this study is promising for the undertaking of future HIV intervention studies.     

First controlled treatment trial of bipolar II hypomania with mixed symptoms: Quetiapine versus placebo

Objectives

To compare the efficacy and safety of adjunctive quetiapine (QTP) versus placebo (PBO) for patients with bipolar II disorder (BDII) currently experiencing mixed hypomanic symptoms in a 2-site, randomized, placebo-controlled, double-blind, 8-week investigation.

Methods

Participants included 55 adults (age 18–65 years) who met criteria for BDII on the Structured Clinical Interview for DSM-IV-TR (SCID). Entrance criteria included a stable medication regimen for ≥2 weeks and hypomania with mixed symptoms (>12 on the Young Mania Rating Scale [YMRS] and >15 on the Montgomery Asberg Depression Rating Scale [MADRS] at two consecutive visits 1–3 days apart). Participants were randomly assigned to receive adjunctive quetiapine (n=30) or placebo (n=25).

Results

Adjunctive quetiapine demonstrated significantly greater improvement than placebo in Clinical Global Impression for Bipolar Disorder Overall Severity scores (F(1)=10.12, p=.002) and MADRS scores (F(1)=6.93, p=.0138), but no significant differences were observed for YMRS scores (F(1)=3.68, p=.069). Side effects of quetiapine were consistent with those observed in previous clinical trials, with sedation/somnolence being the most common, occurring in 53.3% with QTP and 20.0% with PBO.

Conclusions

While QTP was significantly more effective than PBO for overall and depressive symptoms of BDII, there was no significant difference between groups in reducing symptoms of hypomania. Hypomania improved across both groups throughout the study.     

Randomized Controlled Trial in Advance Stage Breast Cancer Patients for the Effectiveness on Stress Marker and Pain through Sudarshan Kriya and Pranayam

Objective:

The objective of this study is to examine the effect of a cognitive, behavioral stress management module of Sudarshan Kriya (SK) and P on levels of serum cortisol and pain among the women suffering from advanced stage breast cancer.

Materials and Methods:

Participants (n = 147) were screened and randomized to receive standard care (n = 69) versus standard along with SK and Pranayam (P) intervention (n = 78) imparted in one 18 hrs workshop spread during 3 days. Participants were expected to practice it at home 20 min daily as adjuvant to standard pharmacological treatment for pain.

Results:

There was a significant difference in blood cortisol levels after 3 months of practice of SK and P. Mean blood levels in the intervention arm were 341.2 ng/ml against 549.2 ng/ml in the control arm (P ≤ 0.002). Pain perception in comparison to control arm reduced by 3 points in SK and P arm on 0-10 verbal scale of pain.

Conclusion:

SK and P is an effective intervention in reducing stress and pain among advance stage patients of breast cancer.     

Clinical profile of acute kidney injury in a pediatric intensive care unit from Southern India: A prospective observational study

Background:

Although the term acute renal failure was replaced by acute kidney injury (AKI) recently, there is a paucity of data on the incidence and profile of AKI in critically ill children from the developing world.

Objectives:

The objective of this study is to determine the incidence, etiology, short term outcome and predictors of fatality in critically ill children admitted to the pediatric intensive care unit (PICU) with AKI, aged 1 month to 13 years.

Materials and Methods:

In this prospective observational study, from June 2010 to March 2011, 215 children admitted to the PICU were screened for AKI, defined according to the AKI Network criteria. The patients with AKI were followed-up until discharge/death. Their clinical and biochemical data were recorded.

Results:

The incidence of AKI among 215 patients screened was 54 (25.1%). The common etiologies were infections, [34 (62.9%)], acute glomerulonephritis (7.6%), snake envenomation (5.7%), hemolytic uremic syndrome (3.8%) and congestive cardiac failures (3.8%). Among infections, pneumonia and septicemia constituted 26.5% each, meningoencephalitis accounted for 23.5%, and dengue, scrub typhus, tuberculosis and malaria constituted 9.3% of children with AKI. 27.8% of patients required dialysis. Overall mortality was 46.3%. On logistic regression analysis, requirement of mechanical ventilation was an independent predictor of fatality in AKI.

Conclusions:

Besides the high incidence of AKI in critically ill-children admitted to the PICU (25.1%), the condition was associated with adverse outcomes, including high mortality (46.3%) and need for dialysis (27.8%). Infections dominated the etiological profile. Requirement of mechanical ventilation predicted an adverse outcome in our patient population.     

Circumspect descent prevails in solving random constraint satisfaction problems

We study the performance of stochastic local search algorithms for random instances of the K-satisfiability (K-SAT) problem. We present a stochastic local search algorithm, ChainSAT, which moves in the energy landscape of a problem instance by never going upwards in energy. ChainSAT is a focused algorithm in the sense that it focuses on variables occurring in unsatisfied clauses. We show by extensive numerical investigations that ChainSAT and other focused algorithms solve large K-SAT instances almost surely in linear time, up to high clause-to-variable ratios alpha; for example, for K = 4 we observe linear-time performance well beyond the recently postulated clustering and condensation transitions in the solution space. The performance of ChainSAT is a surprise given that by design the algorithm gets trapped into the first local energy minimum it encounters, yet no such minima are encountered. We also study the geometry of the solution space as accessed by stochastic local search algorithms.     

Pharmacokinetics of First-Line Antituberculosis Drugs in HIV-Infected Children with Tuberculosis Treated with Intermittent Regimens in India

The objective of this report was to study the pharmacokinetics of rifampin (RMP), isoniazid (INH), and pyrazinamide (PZA) in HIV-infected children with tuberculosis (TB) treated with a thrice-weekly anti-TB regimen in the government program in India. Seventy-seven HIV-infected children with TB aged 1 to 15 years from six hospitals in India were recruited. During the intensive phase of TB treatment with directly observed administration of the drugs, a complete pharmacokinetic study was performed. Drug concentrations were measured by high-performance liquid chromatography. A multivariable regression analysis was done to explore the factors impacting drug levels and treatment outcomes. The proportions of children with subnormal peak concentrations (C_max) of RMP, INH, and PZA were 97%, 28%, and 33%, respectively. Children less than 5 years old had a lower median C_max and lower exposure (area under the time-concentration curve from 0 to 8 h [AUC_0–8]) of INH (C_max, 2.5 versus 5.1 μg/ml, respectively [P = 0.016]; AUC_0–8, 11.1 versus 22.0 μg/ml · h, respectively [P = 0.047[) and PZA (C_max, 34.1 versus 42.3 μg/ml, respectively [P = 0.055]; AUC_0–8, 177.9 versus 221.7 μg/ml · h, respectively [P = 0.05]) than those more than 5 years old. In children with unfavorable versus favorable outcomes, the median C_max of RMP (1.0 versus 2.8 μg/ml, respectively; P = 0.002) and PZA (31.9 versus 44.4 μg/ml, respectively; P = 0.045) were significantly lower. Among all factors studied, the PZA C_max influenced TB treatment outcome (P = 0.011; adjusted odds ratio, 1.094; 95% confidence interval, 1.021 to 1.173). A high proportion of children with HIV and TB had a subnormal RMP C_max. The PZA C_max significantly influenced treatment outcome. These findings have important clinical implications and emphasize that drug doses in HIV-infected children with TB have to be optimized.