加替沙星无菌检查方法的建立与标准操作探讨

目的:建立加替沙星原料及制剂无菌检查法及标准操作方法。方法:按2005年版中国药典无菌检查法验证实验的有关要求,通过接种阳性代表菌株,对薄膜过滤、添加中和剂等去除加替沙星抗菌活性的实验方法和条件进行验证,逐步建立加替沙星原料及制剂无菌检查的标准操作方法。结果:在对加替沙星不同原料及制剂样品适当的处理基础上,采用薄膜过滤法,以0.1%蛋白胨水溶液作为冲洗液,约每滤筒300 mL 的冲洗量,每筒培养基中加入0.1 mol·L~(-1)硫酸锰溶液3 mL 可去除加替沙星对细菌的抑菌作用。结论:加替沙星具有较强的抑菌活性,通过适当的样品处理、薄膜过滤法和添加硫酸锰溶液作为重金属络合剂,去除加替沙星抑菌活性,可对解决喹诺酮类抗生素无菌检查问题起到较好的参考作用。     

保健食品微生物限度检查的方法学验证

目的:确认对保健食品进行微生物限度检查时,昕采用的细菌、霉菌及酵母菌计数和控制菌检查方法是否适合于该保健食品的微生物限度检查。方法:按2005年版中国药典微生物限度检查法及方法学验证实验要求,对21种保健食品进行了方法学验证。结果:10个品种(血尔口服液、金舒通胶囊、事轻松胶囊、梦玉胶囊等)分别对金黄色葡萄球菌和枯草芽孢杆菌有明显的抑菌作用,阳性对照菌回收率均低于70%。结论:保健食品采用 GB/T4789-2003食品卫生微生物学检查法进行检查时,其检验结果可能不够科学,建议参照2005年版中国药典要求,通过方法验证实验建立合理的检验方法。     

Selenium status of New Zealand infants fed either a selenium supplemented or a standard formula

Objective: New Zealand soils are deficient in the essential micronutrient, selenium. New Zealand infants have low selenium levels at birth and experience a further decline if fed cows milk based formula. This study examined the selenium status of infants fed with a new commercially available selenium supplemented formula.
Methodology Forty-four newborn infants, whose mothers wished to formula feed, were randomized in an open controlled trial to be fed a commercially available selenium supplemented cows milk formula (containing 17 μg Se/L) or an unsupplemented formula (containing 4.6 μg Se/L). Cord, 1 and 3 month blood samples were obtained for selenium status (plasma and red cell selenium and glutathione peroxidase) and thyroid function.
Results Mean plasma selenium and glutathione peroxidase values were significantly higher in supplemented than unsupplemented infants at 1 month (unpaired t -tests; P <0.0001 and P = 0.001 respectively) and 3 months ( P <0.0001 and P = 0.0005). Analysis within treatment groups between time points (paired t -tests) showed that selenium supplementation prevented the fall in plasma selenium from birth to 1 month seen in unsupplemented infants and was associated with a rise in levels between 1 and 3 months ( P = 0.002).
Conclusions Supplementing cows milk formula with selenium to replicate the levels found in breast milk is nutritionally sound. Feeding from a few days of age with a formula containing 17 μg Se/L in infants with low selenium status at birth is sufficient to cause a rise to 80% of adult levels at 3 months of age.     

Effects of α4/β2- and α7-nicotine acetylcholine receptor agonists on prepulse inhibition of the acoustic startle response in rats and mice

RATIONALE: Nicotine and agonists at subtypes of the nicotine acetylcholine receptor (nAChR) affect auditory gating, but the magnitude and direction of such effects appear highly variable. This variability may be due to differences in the tested dose range, selectivity of the test compound, species and strain, and suggests that nAChR subtypes are differentially involved in the control of auditory gating. OBJECTIVES AND METHODS: This study aimed to characterise the effects of nicotine and agonists with preferential activity at alpha4/beta2- and alpha7-nAChRs on auditory sensorimotor gating using a prepulse inhibition (PPI) paradigm. Similar experimental conditions were employed in rats and two strains of mice. The paradigm used startle stimuli of 120 dB and prepulse intensities of 3, 6 and 12 dB above a background of 70 dB. RESULTS: In Sprague-Dawley rats, nicotine disrupted PPI [minimal effective dose (MED): 1 mg/kg, SC] and this effect was mimicked by the potent nAChR agonist, epibatidine, (MED: < or = 0.001 mg/kg, IP) and the potent, and relatively selective, alpha4/beta2-nAChR agonist A-85380 (MED: < or = 0.1 mg/kg, IP). The effects of epibatidine, A-85380 and, to a lesser extent, nicotine were blocked by the non-selective nAChR antagonist mecamylamine. The relatively selective alpha7-nAChR agonists, GTS-21 and AR-R-17779, did not affect PPI in a consistent manner, both in rats and in DBA/2 mice, a strain expressing a disrupted gating phenotype, presumably due to altered activity of hippocampal alpha7-nAChRs. In BALB/c mice, a strain expressing a normal gating phenotype, nicotine (MED: 10 mg/kg, SC), epibatidine (MED: 0.03 mg/kg, IP) and A-85380 (MED: 0.3 mg/kg, IP) predominantly augmented PPI and mecamylamine attenuated these effects. CONCLUSIONS: The present results confirm that the effects of nAChR agonists on PPI are species dependent and suggest that stimulation of heteromeric nAChRs containing both alpha and beta subunits, and possibly of the alpha4/beta2 type, affect sensorimotor gating. Evidence supporting a role for alpha7-nAChRs in the control of PPI of the acoustic startle response was not obtained.     

Environmental contexts surrounding resolution of drinking problems among problem drinkers with different help-seeking experiences

OBJECTIVE: This study investigated whether similar environmental contexts surround abstinent resolutions associated with different intervention experiences, including no assistance. METHOD: Participants were selected in a 3 x 2 design (25-30 per group, N = 167) according to their help-seeking experiences (no assistance, Alcoholics Anonymous [AA] only, treatment plus AA) and current drinking status (resolved abstinent [RA] for >2 years or nonresolved [NR] controls). Life events were assessed retrospectively over a 4-year period that spanned the 2 years before and 2 years after the initiation of stable abstinence by RA participants or over a matched interval for NR participants. Collateral or reliability interviews were conducted for 84% of the sample as checks on participant reports. RESULTS: Across help-seeking groups, RA participants reported decreased negative events and increased positive events from the pre- through the post-resolution period. Interventions, especially treatment, enhanced the postresolution improvements in RA participants' life circumstances. This pattern was absent among NR participants. CONCLUSIONS: The findings suggest that a similar molar environmental context surrounds resolutions achieved with and without interventions and that interventions are associated with enhanced improvements during maintenance.     

Epicardial ultrasound in off-pump coronary artery bypass grafting: potential aid in intraoperative coronary diagnostics

BACKGROUND: In off-pump coronary artery bypass surgery (OPCAB), epicardial ultrasound may aid in several intraoperative dilemmas. The aim of this study was to test a new mini-transducer for intraoperative coronary diagnostics. METHODS: A 10 MHz mini-transducer (15 x 6 x 9 mm) was applied epicardially in eight open chest and two closed chest porcine OPCAB procedures (using robotics) and on four postmortem human hearts. The transducer fitted in between the suction pods of the cardiac stabilizer and passed an 11-mm port. RESULTS: In the open chest cases the internal mammary arteries (including the side branches) could be visualized totally (n = 12). The left anterior descending coronary artery could be located over its entire course. Vascular anatomy, side branches, and septal perforators (diameter > or = 0.2 mm) could easily be discerned. In the closed chest cases the left anterior descending coronary artery, its side branches, and septal perforators could be visualized in both cases. In the postmortem human hearts the left anterior descending coronary artery could be visualized totally under the thick epicardial fibro-fatty layer and pathologic conditions could be identified. CONCLUSIONS: The 10 MHz ultrasound mini-transducer showed promise as a diagnostic tool in both open and closed chest coronary procedures on the beating heart.     

Developmental expression of potassium-channel subunit Kv3.2 within subpopulations of mouse hippocampal inhibitory interneurons

The developmental expression of the voltage-gated potassium channel subunit, Kv3.2, and its localization within specific mouse hippocampal inhibitory interneuron populations were determined using immunoblotting and immunohistochemical techniques. Using immunoblotting techniques, the Kv3.2 protein was weakly detected at postnatal age day 7 (P7), and full expression was attained at P21 in tissue extracts from homogenized hippocampal preparations. A similar developmental profile was observed using immunohistochemical techniques in hippocampal tissue sections. Kv3.2 protein expression was clustered on the somata and proximal dendrites of presumed inhibitory interneurons. Using double immunofluorescence, Kv3.2 subunit expression was detected on subpopulations of GABAergic inhibitory interneurons. Kv3.2 was detected in approximately 100% of parvalbumin-positive interneurons, 86% of interneurons expressing nitric oxide synthase, and approximately 50% of somatostatin-immunoreactive cells. Kv3.2 expression was absent from both calbindin- and calretinin-containing interneurons. Using immunoprecipitation, we further demonstrate that Kv3.2 and its related subunit Kv3.1b are coexpressed within the same protein complexes in the hippocampus. These data demonstrate that potassium channel subunit Kv3.2 expression is developmentally regulated in a specific set of interneurons. The vast majority of these interneuron subpopulations possess a "fast-spiking" phenotype, consistent with a role for currents through Kv3.2 containing channels in determining action potential kinetics in these cells.     

CD40-expressing carcinoma cells induce down-regulation of CD40 ligand (CD154) and impair T-cell functions

The interaction of CD40 expressed by immunocompetent cells with its ligand CD154 on the surface of T-helper cells plays a crucial role in the immune response. Recently, the presence of CD40 was also demonstrated on a variety of carcinomas. Whereas the critical relevance of CD40 in cytotoxic T-cell priming via dendritic cells is already established, the biological role of CD40/CD154 interactions in nonhematopoetic cells is still unclear. In the present study we demonstrate that CD154 expression density is down-regulated on activated T cells on interaction with CD40+ tumor cells. Naive T cells cocultured with CD40+carcinoma showed impaired functionality as indicated by a reduced frequency of IFN-gamma secreting cells, reduced interleukin 2 secretion, impaired proliferation, and a lack of CD154 re-expression on restimulation. In distinction, T-cell effector lysing capacity was not impaired by CD40-expressing tumor cell targets. The present results suggest that in marked contrast to antigen-presenting cells, CD40 expression on carcinoma cells suppresses T-cell activation. Our findings support the statement that CD40 functions are context dependent and imply a new function for CD40 expressed on nonantigen-presenting cells.