Prolongation of hippocampal miniature inhibitory postsynaptic currents in mice lacking the GABA(A) receptor alpha1 subunit

GABA(A) receptors (GABA(A)-Rs) are pentameric structures consisting of two alpha, two beta, and one gamma subunit. The alpha subunit influences agonist efficacy, benzodiazepine pharmacology, and kinetics of activation/deactivation. To investigate the contribution of the alpha1 subunit to native GABA(A)-Rs, we analyzed miniature inhibitory postsynaptic currents (mIPSCs) in CA1 hippocampal pyramidal cells and interneurons from wild-type (WT) and alpha1 subunit knock-out (alpha1 KO) mice. mIPSCs recorded from interneurons and pyramidal cells obtained from alpha1 KO mice were detected less frequently, were smaller in amplitude, and decayed more slowly than mIPSCs recorded in neurons from WT mice. The effect of zolpidem was examined in view of its reported selectivity for receptors containing the alpha1 subunit. In interneurons and pyramidal cells from WT mice, zolpidem significantly increased mIPSC frequency, prolonged mIPSC decay, and increased mIPSC amplitude; those effects were diminished or absent in neurons from alpha1 KO mice. Nonstationary fluctuation analysis of mIPSCs indicated that the zolpidem-induced increase in mIPSC amplitude was associated with an increase in the number of open receptors rather than a change in the unitary conductance of individual channels. These data indicate that the alpha1 subunit is present at synapses on WT interneurons and pyramidal cells, although differences in mIPSC decay times and zolpidem sensitivity suggest that the degree to which the alpha1 subunit is functionally expressed at synapses on CA1 interneurons may be greater than that at synapses on CA1 pyramidal cells.     

Identification of cytokines which enhance (CSF-1, IL-3) or restrict (IFN-gamma) growth of intramacrophage Listeria monocytogenes

Murine peritoneal macrophages were isolated by adherence and their listericidal activity assessed in the presence or absence of selected cytokines. Untreated macrophages were not highly listericidal, showing moderate killing in the first 2 h after infection, and allowed progressive microbial growth thereafter (up to 9 h). Pre-treatment of cells with 10 to 100 U/ml of IFN-gamma allowed macrophages to develop sustained listericidal activity for the 9-h observation period, with a 2-log reduction of Listeria CFU per monolayer. Pulsing of cells with TNF-alpha alone did not result in enhanced microbicidal activity but TNF-alpha potentiated IFN-gamma-induced listericidal activity, resulting in high levels of killing when both cytokines were present. Conversely, macrophages pre-treated with interleukin-3 (IL-3) or colony-stimulating factor-1 (CSF-1) were found to be much more permissive for Listeria growth. Neither IL-3 nor CSF-1 abrogated IFN-gamma-induced listericidal activity. Moreover, neither IL-3 nor CSF-1 had any effect on the ability of macrophages to develop a respiratory burst following Listeria infection, as judged by H2O2 release following in vitro infection. Overall, these results suggest that different cytokines may have opposing effects on intracellular microbial growth, and that the balance of cytokine production in vivo may determine the resistance or susceptibility of the infected host.     

Losing culture on the way to competence: the use and misuse of culture in medical education.

Most cultural competence programs are based on traditional models of cross-cultural education that were motivated primarily by the desire to alleviate barriers to effective health care for immigrants, refugees, and others on the sociocultural margin. The main driver of renewed interest in cultural competence in the health professions has been the call to eliminate racial and ethnic disparities in the quality of health care. This mismatch between the motivation behind the design of cross-cultural education programs and the motivation behind their current application creates significant problems. First, in trying to define cultural boundaries or norms, programs may inadvertently reinforce racial and ethnic biases and stereotypes while doing little to clarify the actual complex sociocultural contexts in which patients live. Second, in attempting to address racial and ethnic disparities through cultural competence training, educators too often conflate these distinct concepts. To make this argument, the authors first discuss the relevance of culture to health and health care generally, and to disparities in particular. They then examine the concept of culture, paying particular attention to how it has been used (and misused) in cultural competence training. Finally, they discuss the implications of these ideas for health professions education.     

Use of specific dental treatment procedures by dentate adults during a 24-month period

OBJECTIVES: To (a) describe the incidence of use of specific dental services; (b) test the hypothesis that certain predisposing, enabling, and need (PEN) factors are differentially predictive of service use; and (c) test the hypothesis that even with other PEN factors taken into account, race and household income are differentially predictive of certain dental services. Previously, this study identified PEN factors that predicted use of any care; herein we identify whether these same factors were differentially predictive of specific service use among users of at least one service. METHODS: The Florida Dental Care Study was a longitudinal study of persons aged 45 years or older who had at least one tooth. Subjects participated for interviews and clinical examinations at baseline and 24 months later, with 6-monthly telephone interviews between those times. RESULTS: Seventy-seven percent of subjects reported one or more visits. Results from a single multivariate multiple logistic regression suggested that even once analysis was limited to persons who used at least one dental service, at least one measure from each of the PEN domains was predictive of specific dental service use. CONCLUSIONS: Each PEN domain was predictive of service use, even once limited to persons with at least one visit. Even with differences in other PEN variables taken into account, African-Americans were much less likely to receive dental cleanings, restorative dentistry and fixed prosthodontic services, and were much more likely to have a tooth extracted. Household income was predictive of receipt of fixed prosthodontic services, but not other service categories.     

Genomic-scale prioritization of drug targets: the TDR Targets database

The increasing availability of genomic data for pathogens that cause tropical diseases has created new opportunities for drug discovery and development. However, if the potential of such data is to be fully exploited, the data must be effectively integrated and be easy to interrogate. Here, we discuss the development of the TDR Targets database (http://tdrtargets.org), which encompasses extensive genetic, biochemical and pharmacological data related to tropical disease pathogens, as well as computationally predicted druggability for potential targets and compound desirability information. By allowing the integration and weighting of this information, this database aims to facilitate the identification and prioritization of candidate drug targets for pathogens.     

Identification of a nonbasic, nitrile-containing cathepsin K inhibitor (MK-1256) that is efficacious in a monkey model of osteoporosis

Herein, we report on the identification of nonbasic, potent, and highly selective, nitrile-containing cathepsin K (Cat K) inhibitors that are built on our previously identified cyclohexanecarboxamide core structure. Subsequent to our initial investigations, we have found that incorporation of five-membered heterocycles as P2-P3 linkers allowed for the introduction of a methyl sulfone P3-substitutent that was not tolerated in inhibitors containing a six-membered aromatic P2-P3 linker. The combination of a five-membered N-methylpyrazole linker and a methyl sulfone in P3 yielded subnanomolar Cat K inhibitors that were minimally shifted (<10-fold) in our functional bone resorption assay. Issues that arose because of metabolic demethylation of the N-methylpyrazole were addressed through introduction of a 2,2,2-trifluoroethyl substituent. This culminated in the identification of 31 (MK-1256), a potent (Cat K IC 50 = 0.62 nM) and selective (>1100-fold selectivity vs Cat B, L, S, C, H, Z, and V, 110-fold vs Cat F) inhibitor of cathepsin K that is efficacious in a monkey model of osteoporosis.