谷氨酸诱导体外培养的鸡胚脊髓神经细胞释放NO

用鸡胚脊髓神经细胞的原代培养,测定细胞中亚硝酸盐的含量,研究了谷氨酸(Glu)对原代培养神经细胞中NO的影响。结果表明,谷氨酸作用于原代培养的鸡胚脊髓神经细胞,在诱导神经细胞释放乳酸脱氢酶(LDH)的同时,还可诱导细胞释放一氧化氮(NO)。如先用NO合成酶抑制剂L-NOARG作用细胞,再加入Glu,则发现L-NOARG能降低Glu导致的培养液中LDH活性升高。提示NO可能参与介导Glu的神经毒性作用。     

Systematic review data extraction: cross-sectional study showed that experience did not increase accuracy

ObjectiveThis study assessed the impact of systematic review and data extraction experience on the accuracy and efficiency of data extraction in systematic reviews.Study Design and SettingWe conducted a prospective cross-sectional study from October to December 2006. Participants were classified as having minimal, moderate, or substantial experience in systematic reviews and data extraction. Three studies on insomnia treatment were extracted. Our primary outcome was the accuracy of data extraction. Data sets of each experience level were analyzed for errors in data extraction and results of meta-analyses. Additionally, the time required for completion of data extraction was compared.ResultsError rates were similar across the various levels of experience and ranged from 28.3% to 31.2%. Mean rates for errors of omission (11.3–16.4%) were generally lower than those for errors of inaccuracy (13.9–17.9%). There were no significant differences in error rates or accuracy of meta-analysis results between groups. Time required approached significance, with minimally experienced participants requiring the most time.ConclusionOverall, there were high error rates by participants at all experience levels; however, time required for extraction tended to decrease with experience. These results illustrate the need to develop strategies aimed at mastery of data extraction, rather than reliance on previous data extraction experience alone.     

A crucial role for TNF-α in mediating neutrophil influx induced by endogenously generated or exogenous chemokines,KC/CXCL1 and LIX/CXCL5

Background and purpose:

Chemokines orchestrate neutrophil recruitment to inflammatory foci. In the present study, we evaluated the participation of three chemokines, KC/CXCL1, MIP-2/CXCL2 and LIX/CXCL5, which are ligands for chemokine receptor 2 (CXCR2), in mediating neutrophil recruitment in immune inflammation induced by antigen in immunized mice.

Experimental approach:

Neutrophil recruitment was assessed in immunized mice challenged with methylated bovine serum albumin, KC/CXCL1, LIX/CXCL5 or tumour necrosis factor (TNF)-α. Cytokine and chemokine levels were determined in peritoneal exudates and in supernatants of macrophages and mast cells by elisa. CXCR2 and intercellular adhesion molecule 1 (ICAM-1) expression was determined using immunohistochemistry and confocal microscopy.

Key results:

Antigen challenge induced dose- and time-dependent neutrophil recruitment and production of KC/CXCL1, LIX/CXCL5 and TNF-α, but not MIP-2/CXCL2, in peritoneal exudates. Neutrophil recruitment was inhibited by treatment with reparixin (CXCR1/2 antagonist), anti-KC/CXCL1, anti-LIX/CXCL5 or anti-TNF-α antibodies and in tumour necrosis factor receptor 1-deficient mice. Intraperitoneal injection of KC/CXCL1 and LIX/CXCL5 induced dose- and time-dependent neutrophil recruitment and TNF-α production, which were inhibited by reparixin or anti-TNF-α treatment. Macrophages and mast cells expressed CXCR2 receptors. Increased macrophage numbers enhanced, while cromolyn sodium (mast cell stabilizer) diminished, LIX/CXCL5-induced neutrophil recruitment. Macrophages and mast cells from immunized mice produced TNF-α upon LIX/CXCL5 stimulation. Methylated bovine serum albumin induced expression of ICAM-1 on mesenteric vascular endothelium, which was inhibited by anti-TNF-α or anti-LIX/CXCL5.

Conclusion and implications:

Following antigen challenge, CXCR2 ligands are produced and act on macrophages and mast cells triggering the production of TNF-α, which synergistically contribute to neutrophil recruitment through induction of the expression of ICAM-1.     

The efficacy and safety of bile Acid binding agents, opioid antagonists, or rifampin in the treatment of cholestasis-associated pruritus

OBJECTIVES: The objective of this review was to evaluate the efficacy and safety of rifampin, opioid antagonists, or bile acid binding agents in the treatment of cholestasis-related pruritus (CAP) from available randomized controlled trial evidence. METHODS: In addition to a comprehensive gray literature search, the Cochrane Library, MEDLINE, EMBASE, PubMed, and Web of Science were searched. Only full-text RCTs in participants (>75% adult) with CAP on at least one of the three medications were included. The primary outcome was change in pruritus score, recorded as a continuous or dichotomous outcome. Two independent reviewers performed trial selection and quality assessment. RESULTS: From 487 citations, 12 RCTs were included. Rifampin (standardized mean difference [SMD]-1.62, 95% CI -3.05 to -0.18) and opioid antagonists (SMD -0.68, 95% CI -1.19 to -0.17) significantly reduced CAP. The two cholestyramine studies were too heterogeneous to pool. Although cholestyramine (P= 0.35) and rifampin (P= 0.96) were not associated with greater side effects compared with placebo, opioid antagonists were (number needed to harm = 2.6, 95% CI 1.4-25). CONCLUSIONS: The available RCTs are small, few in number, and use varying scales for measuring pruritus. Although both opioid antagonists and rifampin demonstrated a reduction in pruritus, there were insufficient data to judge the efficacy of cholestyramine. Opioid antagonists were associated with transient side effects in a significant proportion of patients. A longer well-designed randomized controlled trial is needed to confirm the efficacy of bile acid binding agents and accurately assess adverse events.     

Breast MRI: state of the art

Magnetic resonance imaging (MRI) of the breast has emerged as a useful adjunct in evaluation of breast disease. For the past 25 years its use has been explored extensively in the literature and specific clinical indications have been developed. This review will address the current state of the art of breast MRI, including image acquisition, interpretation, limitations, and current applications. We also will discuss briefly emerging techniques that may further advance the practice of breast MRI evaluation.