Evaluation of Screening and Commercial Methods for Detection of Methicillin Resistance in Coagulase-Negative Staphylococci

The National Committee for Clinical Laboratory Standards recommends 48 h of incubation by the oxacillin salt agar screen (OSAS) method for the detection of methicillin-resistant coagulase-negative staphylococci (CoNS). An earlier identification of methicillin resistance is desirable. The time to detection of the mecA gene by PCR was compared with the times to detection by OSAS, by the oxacillin disk diffusion (ODD) method, and with MicroScan Gram Positive Combo type 6 panels (MicroScan Inc. Sacramento, Calif.) and Vitek GPS-SA cards (bioMérieux Vitek Inc., Hazelwood, Mo.). The combination of the Vitek card and the ODD method detected 92 of 99 methicillin-resistant strains of CoNS at 24 h; however, 6 mecA-positive strains were phenotypically methicillin susceptible. We conclude that most methicillin-resistant CoNS can be detected and the results can be reported after overnight incubation by a combination of methods.     

Cannabis and symptoms of PMS and PMDD

Cannabis has been found to alleviate a wide array of medical symptoms, including those that overlap with physical and emotional symptoms of premenstrual syndrome (PMS) and premenstrual dysphoric disorder (PMDD), including insomnia, irritability, depression, and joint pain. Little work has addressed the use of cannabis as a treatment for PMS or PMDD or the role of women’s cannabis treatment expectancies as a predictor of consumption. Women who reported having experienced PMS and PMDD and endorsed lifetime cannabis use (N?=?145), completed an online survey assessing their frequency of cannabis use, PMS/PMDD symptoms, expectancies of cannabis-induced relief from symptoms, as well as cannabis-related problems. Women were found to hold meaningful expectancies that cannabis would treat all PMS/PMDD symptoms, except for overeating/food cravings. Cannabis treatment expectancies were positively associated with PMS/PMDD symptoms and with monthly cannabis use, and were negatively associated with cannabis-related problems. Research should further examine the relationship of cannabis treatment expectancies with individuals’ cannabis use, as findings indicate the potential for these expectancies to serve a punitive or protective role in the development of cannabis-related problems. Increased research on how cannabis might ameliorate symptoms of PMS and PMDD could help establish an alternative treatment plan that offers relief with fewer negative side effects.     

Fetal liver hematopoietic stem cells as a target for in utero retroviral gene transfer.

Retroviral-mediated gene transfer into hematopoietic precursors often results in only short-term gene transduction in vivo. Loss of the transduced genetic material over time may be caused by the limited ability of retroviral infection to transduce genes into early, pluripotent hematopoietic stem cells. Because fetal liver contains actively proliferating multipotential stem cells that should be more susceptible to retroviral-mediated gene transfer than quiescent cells derived from adult bone marrow, these cells may be an ideal target for gene transduction. Furthermore, physiologic expansion of these cells during development obviates the need for marrow ablation during gene therapy in vivo. We performed in utero gene transfer by injecting high titer replication-defective retrovirus in vivo into the livers of 11, 14, 16, and 18 day gestation rats. After birth, the rats were analyzed for the presence of proviral integration and gene expression. The efficiency of gene transfer into bone marrow cells was greatest in rats infected at day 14 to 16 of gestation. In rats killed at 1 to 26 weeks of age, gene transfer was detected by Southern analysis in 48% and by polymerase chain reaction in 86% of bone marrow samples. The provirus was also detected in white blood cells, the granulocyte-macrophage colony-forming unit, thymus, spleen, liver, and lung. The presence of the transgene in bone marrow and other hematopoietic tissues at 26 weeks of age suggests that early hematopoietic precursors present in the fetal liver are susceptible targets for gene transfer and that these cells become resident in the bone marrow of the adult animal. This model is a new technique for gene transduction into proliferating hematopoietic cells in vivo that avoids bone marrow transplantation and has potential application in the correction of genetic defects in utero.     

Warfarin anticoagulation and outcomes in patients with atrial fibrillation: a systematic review and metaanalysis

OBJECTIVE: To examine the relationship between international normalized ratio (INR) and outcomes (major bleeding events and strokes) in patients with atrial fibrillation (AF) receiving anticoagulation with warfarin. METHODS: A systematic review and metaanalysis of studies published in the English language between January 1, 1985, and October 30, 2002, was performed. MEDLINE (PubMed), Current Contents, and relevant reference lists were searched. Studies enrolling patients with nonvalvular AF receiving warfarin anticoagulation were eligible for inclusion if they reported stroke and/or major bleeding events in relation to INR, or time spent in therapeutic range. The risk of bleeds in overanticoagulated patients (INR > 3) and the risk of strokes in underanticoagulated patients (INR < 2) were assessed. RESULTS: Twenty-one studies (6,248 patients) met all inclusion criteria. Of the 21 studies, a target conventional INR of 2 to 3 was used in 9 studies. An INR < 2, compared with an INR > or = 2, was associated with an odds ratio (OR) for ischemic events of 5.07 (95% confidence interval [CI], 2.92 to 8.80). An INR > 3, compared with an INR < or = 3, was associated with an OR for bleeding events of 3.21 (95% CI, 1.24 to 8.28). On average, in the four studies with a target INR range of 2 to 3, patients with AF receiving warfarin spent 61% of time within, 13% of time above, and 26% below the therapeutic range. CONCLUSION: Available evidence indicates that in patients with nonvalvular AF, the risk of ischemic stroke with insufficient warfarin anticoagulation (INR < 2), and the risk of bleeding events with overanticoagulation (INR > 3) are significantly higher relative to patients with AF maintained within the recommended INR of 2 to 3. However, the published data are sparse, heterogeneous, and primarily reported from clinical trials. More studies evaluating clinical outcomes in relation to INR are needed, especially in a real-world setting.     

Neonatal lipopolysaccharide treatment has long‐term effects on monoaminergic and cannabinoid receptors in the rat

Brain inflammation in early life has been proposed to play important roles in the development of anxiety and psychosis‐related behaviors in adulthood, behaviors that rely on the integrity of dopamine and/or serotonin systems. Moreover recent behavioral and anatomical evidence suggests involvement of CB1 receptors in the control of emotion and mood. In this study, we determined the effects of neonatal LPS treatment on dopamine, serotonin, and cannabinoid receptor binding in adulthood. Rats were treated with the bacterial endotoxin lipopolysaccharide (LPS) on postnatal day (PND) 3 and 5. Dopamine D1, D2, serotonin 5HT1A, 5HT2A, and serotonin transporter and cannabinoid CB1 receptor binding across several brain regions were measured autoradiographically in adulthood (PND 85). Neonatal LPS treatment caused a significant increase in dopamine D2 in the nucleus accumbens and olfactory tubercle, a decrease in 5HT1A receptor binding in the hippocampus CA1 and ventromedial hypothalamus. A decrease in CB1 receptor binding after neonatal LPS was observed in the amygdala. Neonatal LPS had no significant impact on dopamine D1, serotonin 5HT2A or serotonin transporter binding in any of the brain regions examined. Our results suggest long lasting, region specific effects and differential impact on dopamine, serotonin and cannabinoid receptor systems following neonatal inflammation, that may form the basis for compromised anxiety and psychosis related behaviors. Synapse, 2013. © 2013 Wiley Periodicals, Inc.     

CFTR (ABCC7) is a hydrolyzable-ligand-gated channel

As the product of the gene mutated in cystic fibrosis, the most common genetic disease of Caucasians, CFTR is an atypical ABC protein. From an evolutionary perspective, it is apparently a relatively young member of the ABC family, present only in metazoans where it plays a critical role in epithelial salt and fluid homeostasis. Functionally, the membrane translocation process it mediates, the passive bidirectional diffusion of small inorganic anions, is simpler than the vectorial transport of larger more complex substrates (“allocrites”) by most ABC transporters. However, the control of the permeation pathway which cannot go unchecked is necessarily more stringent than in the case of the transporters. There is tight regulation by the phosphorylation/dephosphorylation of the unique CFTR R domain superimposed on the basic ABC regulation mode of ATP binding and hydrolysis at the dual nucleotide binding sites. As with other ABCC subfamily members, only the second of these sites is hydrolytic in CFTR. The phosphorylation and ATP binding/hydrolysis events do not strongly influence each other; rather, R domain phosphorylation appears to enable transduction of the nucleotide binding allosteric signal to the responding channel gate. ATP hydrolysis is not required for either the opening or closing gating transitions but efficiently clears the ligand-binding site enabling a new gating cycle to be initiated.