荧光原位杂交法快速鉴定血培养阳性葡萄球菌的临床应用

目的快速鉴定血培养中的金黄色葡萄球菌和凝固酶阴性葡萄球菌(CoNS),结合临床快速判定是否为污染菌。方法采用荧光原位杂交法鉴定血培养中的金黄色葡萄球菌和CoNS,杂交结果若为CoNS,根据临床资料进行判断,并与文献推荐的污染判断法进行结果比较。结果探针的特异性经由标准菌株和临床分离菌株证实。金黄色葡萄球菌探针的特异性和敏感性均为100%,GoNS探针的特异性和敏感性分别为100%和95.5%。179株CoNS中117株判断为污染菌,污染率为68%,与文献推荐的污染判断方法一致。结论荧光原位杂交法适用于血培养中的金黄色葡萄球菌和CoNS的快速鉴定,以排除CoNS污染。     

偏头痛大鼠脑内5-羟色胺1F和诱导型一氧化氮合酶基因的表达变化及针刺的干预效应

目的:前期实验已证实针刺治疗偏头痛疗效优越。观察针刺对偏头痛大鼠脑内5-羟色胺1F和诱导型一氧化氮合酶mRNA表达的调控作用。方法:实验于2005-11/2006-05在中南大学湘雅医院中西医结合研究所实验室完成。①选用SD大鼠40只,按随机数字表法分为4组(n=10),除正常对照组外,其余3组均复制大鼠偏头痛模型。模型对照组只造模,不作其他处理;针刺治疗组造模后进行针刺;针刺预防组针刺后造模电刺激20min。针刺方法:针刺大鼠双侧太冲、阳陵泉穴20min。采用疏密波,电流强度0.3～0.6mA,留针20min,1次/d,共5次。②实验完毕后取脑干及三叉神经节匀浆,采用反转录-聚合酶链反应法测定5-羟色胺1F和诱导型一氧化氮合酶mRNA表达。结果:进入结果分析正常对照组10只,模型对照组、针刺治疗组、针刺预防组各9只,共脱失3只。①与正常对照组比较,模型对照组大鼠诱导型一氧化氮合酶mRNA表达显著增强(P<0.01),5-羟色胺1FmRNA表达显著减弱(P<0.01)。②与模型对照组比较,针刺预防组和针刺治疗组诱导型一氧化氮合酶mRNA表达明显减弱(P<0.01),5-羟色胺1FmRNA表达显著增强(P<0.01)。结论:针刺调控5-羟色胺1F和诱导型一氧化氮合酶mRNA的表达可能是针刺防治偏头痛的分子机制。     

Retrorenal colon: implications for percutaneous diskectomy

It has been recommended that computed tomography (CT) with the patient prone be performed in every patient undergoing percutaneous diskectomy; this would enable detection of a retrorenal location of the colon, which could interfere with the percutaneous procedure. In this evaluation of 346 prone CT studies, only one patient (0.29%) was found to have retrorenal or retropsoas bowel that would have been perforated at diskectomy. Because of this extremely low prevalence, the performance of prone CT in every patient undergoing percutaneous lumbar diskectomy is not believed to be necessary.     

SHIP represses mast cell activation and reveals that IgE alone triggers signaling pathways which enhance normal mast cell survival

The hemopoietic specific, Src homology 2-containing inositol 5' phosphatase (SHIP) hydrolyzes the phosphatidylinositol (PI)-3-kinase generated second messenger, PI-3,4,5-trisphosphate (PIP(3)), to PI-3,4-bisphosphate (PI-3,4-P(2)) in normal bone marrow derived mast cells (BMMCs). As a consequence, SHIP negatively regulates IgE+antigen (Ag)-induced degranulation as well as leukotriene and inflammatory cytokine production. Interestingly, in the absence of SHIP, BMMCs degranulate extensively with IgE alone, i.e. without Ag, suggesting that IgE alone is capable of stimulating signaling in normal BMMCs and that SHIP prevents this signaling from progressing to degranulation. To test this, we compared signaling events triggered by monomeric IgE versus IgE+Ag in normal BMMCs and found that multiple pathways are triggered by monomeric IgE alone and, while they are in general weaker than those stimulated by IgE+Ag, they are more prolonged. Moreover, while SHIP prevents this IgE-induced signalling from progressing to degranulation or leukotriene production it allows sufficient production of autocrine acting cytokines, in part by activation of NFkappaB, to enhance BMMC survival. Interestingly, the activation of NFkappaB and the level of cytokines produced are far higher with IgE than with IgE+Ag. Moreover, IgE alone maintains Bcl-X(L) levels and enhances the adhesion of BMMCs to fibronectin and this likely enhances their survival still further.     

Differential association of phosphatases with hematopoietic co-receptors bearing immunoreceptor tyrosine-based inhibition motifs

A novel family of inhibitory co-receptors has been recently defined according to the presence in their intracytoplasmic domain of immunoreceptor tyrosine-based inhibition motifs (ITIM). In particular, this family includes a low-affinity receptor for IgG, FcγRIIB, which is widely expressed on hematopoietic cells, as well as killer cell inhibitory receptors (KIR) for major histocompatibility complex (MHC) class I proteins, expressed on both T and natural killer (NK) lymphocytes. FcγRIIB and KIR inhibitory function depends upon the tyrosine phosphorylation of their respective ITIM. Phosphorylated FcγRIIB and KIR ITIM bind the tandem SH2 tyrosine phosphatases, SHP-1 and SHP-2. Recently, FcγRIIB has been shown to associate with a polyphosphate inositol 5-phosphatase, SHIP, which appears to be involved in its inhibitory function. Using cell lysate adsorption to phosphorylated ITIM peptides and surface plasmon resonance, we demonstrate here that, in contrast to FcγRIIB, KIR (CD158b: p58.2) do not bind to SHIP, and only recruit SHP-1 and SHP-2. In addition, we show that point mutation of the amino acid residue in position tyrosine-2 of FcγRIIB and KIR ITIM abolihes their binding to SHP-1 and SHP-2, but leaves intact the association of SHIP with FcγRIIB ITIM. These data contribute to the structural definition of ITIM and document a differential recruitment of phosphatases by distinct ITIM. These findings also reveal that diverse strategies of inhibition are used by distinct members of the ITIM-bearing co-receptor family.     

Infectious influenza A and B virus variants with long carboxyl terminal deletions in the NS1 polypeptides

An influenza A virus, A/turkey/Oregon/71, was shown by protein gel analysis to code for an NS1 protein approximately half the size of those of other influenza A viruses. Sequence analysis of the NS gene of this virus revealed a 10 nucleotide deletion resulting in an NS1 protein of only 124 amino acids. This truncated NS1 polypeptide retained its karyophilic pattern as detected by indirect immunofluorescence analysis of virus infected cells. Also, A/turkey/Oregon/71 virus grew to high titer in embryonated chicken eggs comparable to other influenza A viruses. We also identified a laboratory variant of an influenza B virus, clone 201, which codes for a truncated NS1 protein. Sequence analysis revealed a 13 nucleotide deletion resulting in a shortened NS1 protein of only 127 amino acids as compared to other influenza B virus NS1 proteins possessing a length of 281 amino acids. Again as shown for the NS1 proteins of other influenza B viruses the NS1 polypeptide of B virus clone 201 was found to localize in the nucleus of infected cells. It appears that large deletions in the carboxyl terminus of the NS1 proteins of influenza A and B viruses can be tolerated without affecting the functional integrity of the NS1 polypeptide.     

EEG correlates of the response to ECT: a possible antidepressant role of brain-derived neurotrophic factor

Studies on the relationship of electroencephalographic (EEG) data to the therapeutic response to electroconvulsive therapy (ECT) have been carried out since the 1940s, but for many years they did not yield any consistent correlates. Recent studies, however, are providing a growing body of evidence of relationships between the antidepressant response to ECT and both the ictal (recorded during ECT seizures) and interictal (recorded during waking) EEG. These studies appear to be consistent in pointing to the importance of electrophysiologic changes in the prefrontal cortex as a potential mediator of the antidepressant response to ECT. The available findings are reviewed and discussed in light of recent neurophysiologic and neuropsychiatric research, including that related to neurotrophic factors.