长沙地区1409例泌尿生殖道支原体感染者的感染状况及药敏分析

目的了解长沙地区普通人群泌尿生殖道支原体感染的现状及药敏情况,为临床合理用药提供依据。方法收集并回顾性分析湖南省人民医院1 409例门诊泌尿生殖道感染者的支原体培养鉴定结果及其药物敏感试验结果。结果 1 409例门诊样本中,支原体总阳性率为15.3%(215/1409);其中,解脲脲原体(Uu)和人型支原体(Mh)阳性率为11.5%和6.2%,单独感染Uu、单独感染Mh和混合感染Uu+Mh阳性率分别为9.1%、3.8%和2.4%;女性支原体阳性率为22.3%,明显高于男性的3.3%(χ~2=92.378,P0.01);药物敏感性较高的为强力霉素、美满霉素和交沙霉素,耐药性较高的有喹诺酮类和罗红霉素;女性感染者对交沙霉素和壮观霉素的敏感性高于男性,对其他药物的敏感性则明显低于男性。单独Uu感染者对各抗菌药物(环丙沙星和壮观霉素除外)的敏感性均高于单独Mh感染者,而混合Uu+Mh感染者则为药物敏感性最低的一组(对大部分药物的敏感性低于40%)。结论长沙地区普通人群泌尿生殖道支原体感染的阳性率总体较低,但耐药问题依然突出,临床用药时可把四环素类药物和交沙霉素纳入首选,同时依据感染者的性别、感染类型等选择适宜药物进行治疗。     

A toxin-antitoxin module in Bacillus subtilis can both mitigate and amplify effects of lethal stress

Background

Bacterial type-2 (protein-protein) toxin-antitoxin (TA) modules are two-gene operons that are thought to participate in the response to stress. Previous work with Escherichia coli has led to a debate in which some investigators conclude that the modules protect from stress, while others argue that they amplify lethal stress and lead to programmed cell death. To avoid ambiguity arising from the presence of multiple TA modules in E. coli, the effect of the sole type-2 toxin-antitoxin module of Bacillus subtilis was examined for several types of lethal stress.

Methodology/Principal Findings

Genetic knockout of the toxin gene, ndoA (ydcE), conferred protection to lethal stressors that included kanamycin, moxifloxacin, hydrogen peroxide, and UV irradiation. However, at low doses of UV irradiation the ndoA deficiency increased lethality. Indeed, gradually increasing UV dose with the ndoA mutant revealed a crossover response – from the mutant being more sensitive than wild-type cells to being less sensitive. For high temperature and nutrient starvation, the toxin deficiency rendered cells hypersensitive. The ndoA deficiency also reduced sporulation frequency, indicating a role for toxin-antitoxin modules in this developmental process. In the case of lethal antimicrobial treatment, deletion of the toxin eliminated a surge in hydrogen peroxide accumulation observed in wild-type cells.

Conclusions

A single toxin-antitoxin module can mediate two opposing effects of stress, one that lowers lethality and another that raises it. Protective effects are thought to arise from toxin-mediated inhibition of translation based on published work. The enhanced, stress-mediated killing probably involves toxin-dependent accumulation of reactive oxygen species, since a deficiency in the NdoA toxin suppressed peroxide accumulation following antimicrobial treatment. The type and perhaps the level of stress appear to be important for determining whether this toxin will have a protective or detrimental effect.     

Stimulation of host bone marrow stromal cells by sympathetic nerves promotes breast cancer bone metastasis in mice

Bone and lung metastases are responsible for the majority of deaths in patients with breast cancer. Following treatment of the primary cancer, emotional and psychosocial factors within this population precipitate time to recurrence and death, however the underlying mechanism(s) remain unclear. Using a mouse model of bone metastasis, we provide experimental evidence that activation of the sympathetic nervous system, which is one of many pathophysiological consequences of severe stress and depression, promotes MDA-231 breast cancer cell colonization of bone via a neurohormonal effect on the host bone marrow stroma. We demonstrate that induction of RANKL expression in bone marrow osteoblasts, following β2AR stimulation, increases the migration of metastatic MDA-231 cells in vitro, independently of SDF1-CXCR4 signaling. We also show that the stimulatory effect of endogenous (chronic stress) or pharmacologic sympathetic activation on breast cancer bone metastasis in vivo can be blocked with the β-blocker propranolol, and by knockdown of RANK expression in MDA-231 cells. These findings indicate that RANKL promotes breast cancer cell metastasis to bone via its pro-migratory effect on breast cancer cells, independently of its effect on bone turnover. The emerging clinical implication, supported by recent epidemiological studies, is that βAR-blockers and drugs interfering with RANKL signaling, such as Denosumab, could increase patient survival if used as adjuvant therapy to inhibit both the early colonization of bone by metastatic breast cancer cells and the initiation of the "vicious cycle" of bone destruction induced by these cells.     

Prevention of hepatic ischemia-reperfusion injury by green tea extract

These experiments were designed to determine whether green tea extract (GTE), which contains polyphenolic free radical scavengers, prevents ischemia-reperfusion injury to the liver. Rats were fed a powdered diet containing 0-0.3% GTE starting 5 days before hepatic warm ischemia and reperfusion. Free radicals in bile were trapped with the spin-trapping reagent alpha-(4-pyridyl-1-oxide)-N-tert-butylnitrone (4-POBN) and measured using electron spin resonance spectroscopy. Hepatic ischemia-reperfusion increased transaminase release and caused pathological changes including focal necrosis and hepatic leukocyte infiltration in the liver. Transaminase release was diminished by over 85% and pathological changes were almost totally blocked by 0.1% dietary GTE. Ischemia-reperfusion increased 4-POBN/radical adducts in bile nearly twofold, an effect largely blocked by GTE. Epicatechin, one of the major green tea polyphenols, gave similar protection as GTE. In addition, hepatic ischemia-reperfusion activated NF-kappa B and increased TNF-alpha mRNA and protein expression. These effects were all blocked by GTE. Taken together, these results demonstrate that GTE scavenges free radicals in the liver after ischemiareoxygenation, thus preventing formation of toxic cytokines. Therefore, GTE could prove to be effective in decreasing hepatic injury in disease states where ischemia-reperfusion occurs.     

CD14 mediates the innate immune responses to arthritopathogenic peptidoglycan-polysaccharide complexes of Gram-positive bacterial cell walls

Bacterial infections play an important role in the multifactorial etiology of rheumatoid arthritis. The arthropathic properties of Gram-positive bacteria have been associated with peptidoglycan-polysaccharide complexes (PG-PS), which are major structural components of bacterial cell walls. There is little agreement as to the identity of cellular receptors that mediate innate immune responses to PG-PS. A glycosylphosphatidylinositol-linked cell surface protein, CD14, the lipopolysaccharide receptor, has been proposed as a PG-PS receptor, but contradictory data have been reported. Here, we examined the inflammatory and pathogenic responses to PG-PS in CD14 knockout mice in order to examine the role for CD14 in PG-PS-induced signaling. We found that PG-PS-induced responses in vitro, including transient increase in intracellular calcium, activation of nuclear factor-kappaB, and secretion of the cytokines tumor necrosis factor-alpha and interleukin-6, were all strongly inhibited in CD14 knockout macrophages. In vivo, the incidence and severity of PG-PS induced acute polyarthritis were significantly reduced in CD14 knockout mice as compared with their wild-type counterparts. Consistent with these findings, CD14 knockout mice had significantly inhibited inflammatory cell infiltration and synovial hyperplasia, and reduced expression of inflammatory cytokines in PG-PS arthritic joints. These results support an essential role for CD14 in the innate immune responses to PG-PS and indicate an important role for CD14 in PG-PS induced arthropathy.     

红龙利离体培养的植株再生研究(简报)

PLANTREGENERATIONFROMINFITROCULTUREOFPHLLODENDRONERUBESCENSZhangPeng;HuangXiangli;XuXinlan;LingDinghou(SouthChinaInstituteofBotany.AcademiaSinica,Guangzhou510650)(SortthChinaBotanicalGarden,AcademiaSinica.Guangzhou510520)红龙利是华南地区新引进的名贵热带观叶植物,属天南星科,喜林芋属。其株体茎攀援,茎叶呈紫红色,叶片正面具光泽,为适于室内栽培的优良观叶花卉。红龙利采用常规分株繁殖,因此存在繁殖速度慢、系数低等问题。植物组织培养技术在促进园艺植物事业的发展上取得了引…     

外源一氧化氮提高一年生黑麦草抗冷性机制

用不同浓度的一氧化氮(NO)供体硝普纳(sodiumnitroprusside,SNP)处理低温胁迫下1年生黑麦草幼苗,探讨外源NO对提高黑麦草幼苗抗冷性的作用。结果表明外源NO能减缓低温胁迫下黑麦草幼苗质膜相对透性的增加,促进脯氨酸(Pro)的积累,提高超氧化物歧化酶(SOD)、过氧化氢酶(CAT)和过氧化物酶(POD)保护酶活性,其中POD酶活性的提高尤为显著。恢复生长时,经SNP处理的幼苗膜透性、脯氨酸和保护酶活性恢复较快,其中0.5mmol/LSNP处理的效果最为明显,0.2、1.0mmol/LSNP处理的效果次之。     

对虾—罗非鱼—缢蛏封闭式综合养殖的水质研究

研究了对虾,罗非鱼和缢蛏封闭式综合养殖的环境状况,结果表明,混养各组环境状态总体要优于单养组,实验期间混养组DO的波动幅度略小于单养组,最低值则高于单养组;各混养组COD值和水层细菌数量相互差异不显著,但各混养组均显著低于单养组（t-检验,α＜0．05）,混养围隔水体有机质含量明显低于单养;混养各围隔组中浮游生物生物量,Chl.a均低于且,滤食性动物对浮游生物的压制作用明显,在底泥中,混养组N,P的积累量比单养组低39．76％和51．26％,混养组细胞总数则比单养组低7．63％,本研究表明,封闭式综合养殖可以大大减少注入近海的养殖污水的排放量,从而降低对近海水质的污染。