Carbapenem-hydrolyzing oxacillinase in high resistant strains of Acinetobacter baumannii isolated from India

Acinetobacter baumannii, a Gram negative bacterium causes nosocomial infections including bacteremia, secondary meningitis and urinary tract infections. Increased resistance of A. baumannii has been global concern. Till recently, carbapenems, latest generation of β-lactams are used for treating infections caused by A. baumannii. Emerging resistance to carbapenem class is an immediate threat to mankind. The objective of present study is to understand the growing carbapenem resistance of A. baumannii. By using iso-electric focusing followed by (in-gel) nitrocefin assay of carbapenem resistant strains of A. baumannii, we could identify three β-lactamases with pIs in the range 5.4-9.5. Expression of the β-lactamase with a pI ≈ 8.5, was found only in very high carbapenem resistant (MIC for imipenem 128 μg/ml) strains. On PCR analysis and sequencing of PCR product, this β-lactamase was confirmed to be OXA-51. Identification of this protein from IEF gel was reconfirmed with the help of Liquid chromatography and Tandem mass spectrometry (LC-MS/MS). Based on the amino acid sequence, OXA-51 found to be a 30 kDa β-lactamase containing conserved functional motifs of class D serine β-lactamase. In the present study, we have established the emergence of OXA-51 in clinical strains of A. baumannii in India which suggests its role in carbapenem resistance.     

Functional polymorphisms in <Emphasis Type="Italic">XRCC</Emphasis>-<Emphasis Type="Italic">1</Emphasis> and <Emphasis Type="Italic">APE</Emphasis>-<Emphasis Type="Italic">1</Emphasis> contribute to increased apoptosis and risk of ulcerative colitis

Objective  

The present study was designed to investigate the role of X-ray cross-complementing group 1 (XRCC1) and apurinic/apyrimidinic endonuclease 1 (APE1) polymorphisms in apoptosis and the risk of ulcerative colitis (UC).     

Natural genetic variation in yeast longevity

The genetics of aging in the yeast Saccharomyces cerevisiae has involved the manipulation of individual genes in laboratory strains. We have instituted a quantitative genetic analysis of the yeast replicative lifespan by sampling the natural genetic variation in a wild yeast isolate. Haploid segregants from a cross between a common laboratory strain (S288c) and a clinically derived strain (YJM145) were subjected to quantitative trait locus (QTL) analysis, using 3048 molecular markers across the genome. Five significant, replicative lifespan QTL were identified. Among them, QTL 1 on chromosome IV has the largest effect and contains SIR2, whose product differs by five amino acids in the parental strains. Reciprocal gene swap experiments showed that this gene is responsible for the majority of the effect of this QTL on lifespan. The QTL with the second-largest effect on longevity was QTL 5 on chromosome XII, and the bulk of the underlying genomic sequence contains multiple copies (100–150) of the rDNA. Substitution of the rDNA clusters of the parental strains indicated that they play a predominant role in the effect of this QTL on longevity. This effect does not appear to simply be a function of extrachromosomal ribosomal DNA circle production. The results support an interaction between SIR2 and the rDNA locus, which does not completely explain the effect of these loci on longevity. This study provides a glimpse of the complex genetic architecture of replicative lifespan in yeast and of the potential role of genetic variation hitherto unsampled in the laboratory.Aging is determined by genes, environment, and chance. The budding yeast Saccharomyces cerevisiae (baker''s yeast) has been used as a model organism in the genetics of aging and longevity since the early 1990s (Jazwinski 2004), and lifespan has been analyzed in two different ways in this organism. Replicative lifespan (RLS) refers to the number of times an individual cell divides, while chronological lifespan (CLS) denotes the time spent in stationary culture before a cell loses viability. The number of genes implicated in the RLS and in the CLS of yeast grows continuously (Steinkraus et al. 2008), and a search of the Saccharomyces Genome Database reveals some 242 genes to date (see http://www.yeastgenome.org). This progress has been made through the genetic manipulation of laboratory yeast strains, but not all of the genetic effects on longevity that have been described are identically operable across all laboratory strain backgrounds examined. An informative case in point is the extension of RLS in yeast strains devoid of mitochondrial DNA (Kirchman et al. 1999), in which the retrograde response is commonly induced (Liu and Butow 2006). The retrograde response is an intracellular signaling pathway from the mitochondrion to the nucleus that is triggered by mitochondrial dysfunction and results in the activation of numerous nuclear genes that compensate for this dysfunction (Liu and Butow 2006; Miceli et al. 2011). A comparison of four strains showed varying effects on RLS, spanning RLS extension through curtailment. However, extension was found in each strain when the retrograde response was activated, which in some strains is glucose repressed (Kirchman et al. 1999). This effect has been confirmed by others (e.g., Heeren et al. 2009). It constitutes an example of the impact of gene interactions in determining longevity (Flint and Mackay 2009).Laboratory strains are derived from wild isolates adapted to growth in the laboratory. For yeast, this generally means rapid growth and smooth colony morphology that facilitates picking and streaking (cloning). The evolutionary rate of laboratory strains surpasses that of some wild isolates (Gu et al. 2005; Ronald et al. 2006). Furthermore, the process of picking single colonies, all the cells of which are genetically identical, results in population bottlenecks, which favor the accumulation of deleterious mutations (Hartl and Clark 1997). This raises the possibility that the longevity genes isolated in laboratory strains may simply correct the effects of these deleterious mutations.Yeasts appear to be clonal in the wild, implying little opportunity for sexual reproduction and the attendant genetic segregation and recombination (Tibayrenc et al. 1991). This is not surprising because S. cerevisiae is homothallic in nature. A single haploid spore on germination quickly gives rise to cells that switch mating type and reconstitute the predominant diploid in a homozygous state (Herskowitz 1988). The distinction between wild and laboratory strains is that the former are continuously subjected to selective forces imposed by the ecological niche in which they reside. These forces are likely to be different than those normally found in the laboratory. Even in the laboratory, the imposition of modest selective pressure results in waves of mutations waxing and waning across a yeast population (Adams 2004).The above considerations imply that genes implicated in aging and longevity in laboratory strains may not play the same role in wild yeast strains and that genetic analysis of wild strains may reveal a different set of genetic determinants of longevity. This is not a trivial alternative that simply expands the repertoire of longevity genes. The question of what genes can affect lifespan is quite different from the question of what genes actually do normally affect lifespan. This is highlighted by the recent demonstration that 65% of the long-lived mutants in a laboratory strain showed reduced fitness relative to the wild type (Delaney et al. 2011). Similar results have been obtained in the Caenorhabditis elegans model system (Jenkins et al. 2004). The other major genetic models used in aging research, Drosophila melanogaster and Mus musculus, are also inbred and adapted to the laboratory, raising identical concerns, while the focus on natural genetic variation in human aging is an obvious contrast.Natural yeast variation has been queried to identify quantitative trait loci (QTLs) and genes that play a role in heat resistance, multidrug resistance, ethanol tolerance, acetic acid production during alcoholic fermentation, gene expression, spontaneous mitochondrial genome instability, proteome variation, and telomere length (Winzeler et al. 1998; Steinmetz et al. 2002; Brem et al. 2005; Gatbonton et al. 2006; Foss et al. 2007; Hu et al. 2007; Marullo et al. 2007; Dimitrov et al. 2009). Most of these studies have utilized gene expression microarrays that can query several thousands of single-nucleotide polymorphisms across the yeast genome (Winzeler et al. 1998). Here, we have used this strategy to map QTLs associated with RLS in S. cerevisiae. We sampled the natural genetic variation in a clinically derived S. cerevisiae strain, YJM789, by analyzing haploid segregants generated from a cross with the standard laboratory strain S288c (Steinmetz et al. 2002). The genomic sequences of both YJM789 (Wei et al. 2007) and S288c (Goffeau et al. 1996) have been determined. YJM789 and S288c differ at 60,000 bp throughout their genomes.     

Safety-promoting behaviors of community-dwelling abused Chinese women after an advocacy intervention: a randomized controlled trial

ObjectiveTo examine the effect of an advocacy intervention on the use of safety-promoting behaviors in community-dwelling abused Chinese women as compared to a control condition of usual care.DesignThis efficacy trial used a randomized controlled, parallel group design.Participants and methodsA total of 200 Chinese women in a community setting who screened positive for intimate partner violence using the Chinese version of the Abuse Assessment Screen were randomized to receive either an advocacy intervention (intervention group, n = 100) or usual community care (control group, n = 100). The outcome measured was the change in the self-reported safety-promoting behaviors as measured by the Safety-promoting Behavior Checklist over three time-points (baseline, 3-month follow-up and 9-month follow-up). Participants and assessors were blinded to the study hypothesis. Assessors were further blinded to the group membership of the participants.ResultsThe Safety-promoting Behavior Checklist scores in the intervention group increased from the baseline on average by 5.65 (95% confidence interval [CI], 4.92–6.39) at 3-month and 6.65 (95% CI, 5.90–7.39) at 9-month follow-ups, while the scores in the control group also increased by 1.71 (95% CI, 1.06–2.37) at 3-month and 1.79 (95% CI, 1.15–2.43) at 9-month follow-ups. After adjusting for baseline differences, the between-group differences in scores were significant at 3-month and 9-month follow-ups (p = 0.04). The intervention group increased the scores by 3.61 (95% CI, 2.61–4.61, p < 0.001) more than the control group at 3-month and by 4.53 (95% CI, 3.53–5.53, p < 0.001) at 9-month follow-ups.ConclusionAn advocacy intervention is efficacious in increasing the use of safety-promoting behaviors as compared to usual community care in community-dwelling abused Chinese women.     

Foetal phonocardiographic signal denoising based on non-negative matrix factorization

Foetal phonocardiography (fPCG) is a non-invasive, cost-effective and simple technique for antenatal care. The fPCG signals contain vital information of diagnostic importance regarding the foetal health. However, the fPCG signal is usually contaminated by various noises and thus requires robust signal processing to denoise the signal. The main aim of this paper is to develop a methodology for removal of unwanted noise from the fPCG signal. The proposed methodology utilizes the non-negative matrix factorization (NMF) algorithm. The developed methodology is tested on both simulated and real-time fPCG signals. The performance of the developed methodology has been evaluated in terms of the gain in signal-to-noise ratio (SNR) achieved through the process of denoising. In particular, using the NMF algorithm, a substantial improvement in SNR of the fPCG signals in the range of 12-30 dB has been achieved, providing a high quality assessment of foetal well-being.     

Pharmacogenetics of antipsychotic-induced weight gain: review and clinical implications

Second-generation antipsychotics (SGAs), such as risperidone, clozapine and olanzapine, are the most common drug treatments for schizophrenia. SGAs presented an advantage over first-generation antipsychotics (FGAs), particularly regarding avoidance of extrapyramidal symptoms. However, most SGAs, and to a lesser degree FGAs, are linked to substantial weight gain. This substantial weight gain is a leading factor in patient non-compliance and poses significant risk of diabetes, lipid abnormalities (that is, metabolic syndrome) and cardiovascular events including sudden death. The purpose of this article is to review the advances made in the field of pharmacogenetics of antipsychotic-induced weight gain (AIWG). We included all published association studies in AIWG from December 2006 to date using the Medline and ISI web of knowledge databases. There has been considerable progress reaffirming previous findings and discovery of novel genetic factors. The HTR2C and leptin genes are among the most promising, and new evidence suggests that the DRD2, TNF, SNAP-25 and MC4R genes are also prominent risk factors. Further promising findings have been reported in novel susceptibility genes, such as CNR1, MDR1, ADRA1A and INSIG2. More research is required before genetically informed, personalized medicine can be applied to antipsychotic treatment; nevertheless, inroads have been made towards assessing genetic liability and plausible clinical application.     

Cerebral oxygen metabolism of rats using injectable 15O-oxygen with a steady-state method

To develop a less-stressful and simple method for measurement of the cerebral metabolic rate of oxygen (CMRO₂) in small animals, the steady-state method was applied to injectable ¹⁵O₂-PET (¹⁵O₂-positron emission tomography) using hemoglobin-containing vesicles (¹⁵O₂-HbV). Ten normal rats and 10 with middle cerebral arterial occlusion (MCAO) were studied using a small animal PET scanner. A series of ¹⁵O-PET scans with C¹⁵O-labeled HbV, H₂¹⁵O, and ¹⁵O₂-HbV were performed with 10 to 15 minutes intervals to measure cerebral blood volume (CBV), cerebral blood flow (CBF), and CMRO₂. Positron emission tomography scans were started with a tracer injection using a multiprogramming syringe pump, which provides a slowly increasing injection volume to achieve steady-state radioactivity for H₂¹⁵O and ¹⁵O₂-HbV scans. The radioactivity concentration of ¹⁵O rapidly achieved equilibrium in the blood and whole brain at about 2 minutes after H₂¹⁵O and ¹⁵O₂-HbV administration, which was stable during the scans. The whole brain mean values of CBF, CBV, and CMRO₂ were 54.3±2.0 mL per 100 g per minute, 4.9±0.4 mL/100 g, and 2.8±0.2 μmoL per g per minute (6.2±0.4 mL per 100 g per minute) in the normal rats, respectively. In the MCAO model rats, all hemodynamic parameters of the infarction area on the occlusion side significantly decreased. The steady-state method with ¹⁵O-labeled HbV is simple and useful to analyze hemodynamic changes in studies with model animals.     

Can diffusion tensor imaging (DTI) identify epileptogenic tubers in tuberous sclerosis complex? Correlation with α-[11C]methyl-L-tryptophan ([11C] AMT) positron emission tomography (PET)

In this study, we determined whether diffusion tensor imaging (DTI), a more widely available imaging modality, is as effective as α-[(11)C]methyl-l-tryptophan (AMT)-positron emission tomography (PET) in localizing epileptogenic tubers in tuberous sclerosis complex. Following that, coregistration of AMT-PET and diffusion tensor imaging scans apparent diffusion coefficient (ADC) and fractional anisotropy (FA) were measured in all tubers using a region-of-interest approach and were compared with AMT-PET tuber/cortex uptake ratios, which were used to differentiate between epileptogenic and nonepileptogenic tubers. Forty-three tubers, out of a total of 320 tubers, had AMT-PET uptake ratios greater than 1 and hence were classified as potentially epileptogenic. FA in epileptogenic tubers was reduced compared with the other tubers (P = .03). A significant negative correlation was observed between AMT-PET uptake ratio of epileptogenic tubers and FA values (r = -.45; P = .003). Tubers with higher AMT-PET uptake ratios corresponded well with lower FA values in tuberous sclerosis complex patients.