Evaluation of MicroScan rapid gram-positive panels for detection of oxacillin-resistant staphylococci.

The ability of MicroScan rapid panels (Baxter MicroScan, West Sacramento, Calif.) to detect oxacillin resistance in 92 clinical isolates of Staphylococcus aureus and 103 coagulase-negative staphylococci was evaluated by comparing results with those of MicroScan 24-h MIC panels and, to resolve discrepancies, oxacillin agar screening. Both panels were interpreted by the MicroScan WalkAway-96 system. Rapid panels detected 96.7% of resistant S. aureus isolates and 72% of resistant coagulase-negative staphylococci, 22 of which did not grow in the panels.     

Factors influencing determination of high-level aminoglycoside resistance in Enterococcus faecalis.

The ability of seven methods to detect high-level gentamicin (58 strains) and streptomycin resistance (56 strains) among 107 Enterococcus faecalis isolates was investigated at the University of Chicago Medical Center and the University of Nebraska Medical Center. Methods included a standard agar screen plate, high-content disk diffusion, Remel (Lenexa, Kans.) EF Synergy Quad plates, standard microdilution panels prepared in house, Pasco MIC Gram-Positive panels (Difco Laboratories, Detroit, Mich.), MicroScan MIC Type 5 dry panels (Baxter Healthcare Corp., MicroScan Div., West Sacramento, Calif.), and Vitek GPS-TA cards (Vitek Systems Inc., Hazelwood, Mo.). Results indicating false resistance were not obtained by any method, and there was 100% agreement between the results of the disk diffusion and standard agar screen methods. Prolonging incubation from 24 to 48 h increased resistance detection for both agar and microdilution screens. EF Synergy Quad plates inoculated with micropipettes detected 100% of the streptomycin- and gentamicin-resistant isolates. Resistance detection for streptomycin and gentamicin, respectively, was 93 and 96% by standard microdilution, 93 and 98% by Pasco panels, 88 and 89% by MicroScan panels, and 88 and 91% by Vitek GPS-TA cards. False susceptibility occurred more frequently with streptomycin-resistant isolates than it did with gentamicin-resistant strains and appeared to be strain related in some instances. The use of an increased inoculum size enhanced resistance detection with these strains, but it complicated interpretation of results and led to the selection of streptomycin-resistant mutants. Until results of further studies delineate optimum test conditions, a delay in the final interpretation of agar and microdilution screen results until 48 h for isolates showing no or light growth at 24 h may help to minimize the occurrence of false susceptibility reporting.     

HIV infection and associated risks among young men who have sex with men in a Florida resort community

OBJECTIVE: Several recent studies have reported high rates of sexual risk-taking and HIV infection among young men who have sex with men (MSM). Most of these studies used samples of convenience. The authors obtained population-based data on young MSM living in South Beach (Miami Beach, Florida), a resort community where some of the highest AIDS rates in the United States have been reported. METHODS: A household probability sample was drawn to survey unmarried 18- to 29-year-old MSM living in South Beach. Subjects were interviewed, completed self-administered questionnaires, and provided oral specimens for HIV antibody testing. RESULTS: From the 2,622 screened residential units, 100 mostly white and Hispanic MSM (92.6% of eligible participants) were enrolled in the study. Fifteen percent of the sample tested positive for antibodies to HIV. White and Hispanic MSM had similar rates. Forty-five percent of the sample reported engaging in unprotected anal intercourse (UAI) in the prior 12 months, and 31% reported UAI with a nonprimary partner. The estimated annual incidence of HIV infection was 6.3%. CONCLUSION: The high prevalences of UAI and HIV infection in South Beach attest to a previously undocumented public health concern. The extremely high estimated incidence for young MSM in South Beach highlights the urgent need for more effective risk-reduction interventions and further epidemiological research on resort areas.     

非受体型酪氨酸激酶-Syk蛋白的提取与纯化

目的 :从转染syk基因的Sf2 1细胞中提取、纯化免疫相关因子Syk蛋白。方法 :将syk基因转染Sf2 1细胞 ,于 2 8℃培养 48h ,收集细胞 ,用超声波破碎仪裂解细胞 ,提取裂解液中总蛋白 ,用Yellow 3凝胶和Toyopearl AF Heptin 650M凝胶层析柱分离、纯化。层析液中的Syk蛋白存在和性质 ,用SDS PAGE、免疫印迹实验和等电聚焦实验鉴定。结果 :从 2 5亿个Sf2 1细胞裂解液中提取了含有Syk的 2 2 5mg蛋白质。经Yellow 3凝胶层析分离 ,得到两个亚种的Syk蛋白 ,相对分子质量 (Mr)均为72× 10 3 。进一步用Toyopearl AF Heptin 650M凝胶层析纯化后 ,得到两个纯的Syk蛋白 ,SDS PAGE、免疫印迹实验结果显示 ,两种Syk的Mr 均为 72× 10 3,与Syk的理论相对分子质量吻合。但等电聚焦实验显示 ,这两种Syk蛋白成分具有不同的pI值。结论 :从 2 5亿个转染syk基因的Sf2 1细胞中纯化出8mgSyk蛋白 ,纯度高于 95%。这两种Syk的Mr 虽然相同 ,但具有不同的pI值 ,是两个亚种。这些Syk可用于研究Syk的作用机制、抗Syk抗体的制备和Syk诊断试剂盒的制备等     

Altered feeding responses in mice with targeted disruption of the dopamine-3 receptor gene

Dopamine signaling has been implicated in the control of food intake and body weight. In particular, dopamine is important in the control of meal size and number and is thought to mediate the response to metabolic deprivation states. In the present experiments, the authors assessed the role of the dopamine-3 receptor (D3R) in the feeding responses to 2-deoxy-D-glucose, mercaptoacetate, and peripheral insulin. All 3 compounds increased food intake in wild-type mice, but the hyperphagic responses were blunted in D3R-/- mice. In other experiments, D3R-/- mice were hyperresponsive to the administration of amylin and leptin relative to wild-type mice. These results support the hypothesis that D3Rs chronically inhibit the effects of adiposity hormones, thereby contributing to a net anabolic state.