石家庄地区汉族人群DIS80(pMCT118)位点VNTR基因频率分布调查

本文采用ＰＣＲ技术对石家庄地区２１６名无关个体ＤＩＳ８０（ｐＭＣＴ１１８）位点扩增片段长度多态性的等位基因频率进行调查。ＰＣＲ扩增产物采用聚丙烯酰胺凝胶电泳分型及溴化乙锭染色，共检出７０种基因型，２５个等位基因，其中以１８、２４、３０三个等位基因频率最高。将本文结果与日本人群在ＤＩＳ８０（ｐＭＣＴ１１８）位点多态性结果进行比较，石家庄地区汉族人群ＤＩＳ８０（ｐＭＣＴ１１８）位点基因频率分布符合ＨａｒｄｙＷｅｉｎｂｅｒｇ平衡定律，该位点非父排除率为０．７１，个体识别率为０．９，杂合度为０．８５。     

Investigation of Role of Nitric Oxide in Protection from Bordetella pertussis Respiratory Challenge

The mechanism whereby whole-cell pertussis vaccines (WCV) confer protection against Bordetella pertussis is still not fully understood. We have previously reported that macrophage activation produced by vaccination with WCV is associated with induction of NO synthesis by macrophages in response to in vitro stimulation with B. pertussis antigens. To determine whether NO production is an effector of protection or simply a marker of activation, the susceptibility of inducible nitric oxide synthase (type II, iNOS) knockout mice to infection with B. pertussis was examined. We showed that iNOS knockout mice were more susceptible to B. pertussis respiratory challenge than wild-type mice. iNOS-deficient mice also developed a less effective protective response than wild-type mice after the same immunization with WCV. This suggests that NO plays an important role in effecting protection against B. pertussis challenge.     

Spermidine synthase of Escherichia coli: localization of the speE gene.

We have obtained Escherichia coli mutants lacking spermidine synthase (putrescine aminopropyltransferase) and have found that the mutated gene (speE) is located immediately upstream from the gene coding for S-adenosylmethionine decarboxylase (speD); these genes are located at 2.7 minutes on the E. coli chromosome. Both genes are present in a 1795-base-pair fragment of E. coli DNA that was cloned into pBR322. Deletion of 105 bases upstream of speE caused a coordinate loss of both activities, indicating that speE and speD constitute a single operon. speE and speD have also been cloned separately in a high-expression vector; strains carrying these plasmids overproduce the respective enzymes.     

Effect of gradual rise in plasma calcium concentration on the impairment of atrioventricular nodal conduction due to verapamil

The possible reversal by calcium of the inhibitory action of verapamil on the atrioventricular (AV) node was investigated in anesthetized, atropinized dogs, with cardiac pacing. The His bundle potentials were recorded by endocavitory electrode and the AV node effective refractory period measured by the extrastimulus method. Calcium infusion was effective against the impairment of AV nodal conduction induced by verapamil, provided it remained moderate: the gradual rise in the plasma calcium concentration counteracted the effects of an infusion of verapamil on conduction time and effective refractory period in the AV node, as long as it did not exceed 5 mmol/L. However, beyond this level, calcium appeared less and less capable of reversing the effects of verapamil. Thus, the protective action of calcium had a bell-shaped dose-response curve, with the optimum at 5 mmol/L. This biphasic influence is consistent with the opposite opinions previously given concerning the antagonism between calcium and calcium blockers, depending on whether hypercalcemia brought into play was mild or major. In any case, the prominent role played by calcium in the slow inward current in the AV node accounts for the antagonism, observed in vivo, between calcium and verapamil. The pacemaker activity of the sinoatrial (SA) node was less influenced by both calcium blocker and calcium.     

输卵管积水造口术对体外受精与胚胎移植的影响

【目的】探讨在体外受精与胚胎移植 (IVF ET)之前输卵管积水患者行输卵管造口术对IVF ET治疗效果的影响。【方法】回顾分析 1999年 2月至 2 0 0 1年 1月因女性输卵管因素不孕行IVF ET治疗的 90 8个周期的资料。按输卵管积水患者在IVF ET前是否治疗分 3组 ,A组 :输卵管积水未手术治疗行IVF ET 2 3个周期 ,B组 :在IVF ET之前行输卵管积水造口术 (腹腔镜下或开腹 ) 2 2个周期 ,C组 :对照组 (输卵管阻塞 ,未发现输卵管积水 ) 86 3个周期。【结果】A组、B组、C组的IVF ET的种植率分别为 9 7%、17 9%、16 7% ,临床妊娠率分别为 2 1 7%、4 0 9%、39 2 %。A组的种植率及临床妊娠率比其它组低 ,经 χ2 检验 ,有统计学意义。【结论】输卵管积水未治疗行IVF ET的种植率及临床妊娠率较低 ,但在IVF ET之前行输卵管造口术可改善IVF ET的种植率及临床妊娠率     

Functional recognition of the neuronal tyrosine hydroxylase cAMP regulatory element in different cell types.

Transient transfection of pLB2CAT constructs bearing short synthetic oligonucleotides derived either from the tyrosine hydroxylase (TH) promoter or other sources was used to examine functional cAMP regulatory element (CRE) activity in a variety of cell lines. The region containing only the putative TH CRE was found to be as or more effective in conferring cAMP responsiveness onto pLB2CAT (which employs the TK promoter) than the immediate 272 bp region of the TH promoter. Increases in CAT activity of 10- to 20-fold were observed in JEG-3 cells with a single insert of the TH CRE region (-31 to -54) in pLB2CAT, and the presence of a second insert generated only a modest further increase. This construct also responded to cAMP in 4 other cell lines tested but the degree of increase was less dramatic. Inserts containing the consensus 8 bp CRE motif embedded in other natural or artificial contexts served generally as weak functional CREs in all cell lines tested. In vitro analysis revealed that a specific protein-DNA complex apparently containing a single protein with a MW of 45-50 kDa was formed equally well with JEG-3 cell nuclear extract and CRE-bearing-TH and other fragments which produced dramatically different cAMP effects in vivo. These results suggest specificity in the effects of cAMP on different CREs which are dictated by contextual differences.     

Calcium-activated proteolysis of intracellular domains in the cell adhesion molecules NCAM and N-cadherin.

One of the consequences of increased intracellular calcium in response to a variety of physiological stimuli is the calcium activation of cytosolic proteases. Unlike lysosomal proteases with broad specificity, these calcium-activated neutral proteases show limited proteolysis of a restricted set of substrate proteins suggesting they may play a regulatory role in cellular physiology. In this study we show that the neural cell adhesion molecules NCAM-180 and N-cadherin are substrates for such endogenous calcium-activated neutral proteases. In contrast, a third neural cell adhesion molecule G4/L1 was not susceptible to calcium-activated proteolysis. The threshold for activation of NCAM and N-cadherin proteolysis is in the micromolar range of calcium suggesting that NCAM and N-cadherin are substrates for a mu-type calpain (calpain I). The site recognized by this protease is within intracellular domains of NCAM-180 and N-cadherin which are important for their interaction with cytoskeletal components. These results suggest that calcium-activated proteolysis at these sites in vivo could disrupt the linkage between extracellular ligand binding to these adhesion molecules and the normal intracellular effectors of such extracellular binding events.     

Intracellular Ca2+ suppressed a transient potassium current in hippocampal neurons

The effects of intracellular Ca2+ (Ca2+i) on K+ currents in hippocampal cells were examined using acutely isolated cells obtained from adult guinea pigs. Whole-cell voltage-clamp recordings were carried out in a configuration that allowed a continuous perfusion of the intracellular medium. Recording media were made to block inward currents and allowed selective activation of K(+)-dependent outward currents. Voltage-dependent outward currents consisted of an initial rapidly decaying component followed by a sustained component. The time constant of decay of the transient current was about 25 msec, and previous studies (Numann et al., 1987) showed that the kinetic and pharmacological properties of this current closely resembled the A current recorded in invertebrate neurons (Connor and Stevens, 1971; Thompson, 1982). Intracellular perfusion of hippocampal cells with a solution containing elevated Ca2+ (about 4.5 x 10(-4) M) elicited outward currents at the holding potential (-45 to -55 mV) and produced changes in voltage-dependent K+ currents. The transient outward current (IA) activated by depolarization was suppressed with increases in Ca2+i. Delayed, sustained K+ currents were greatly potentiated. Data also showed that, among the 3 effects elicited by Ca2+i, suppression of IA was most sensitive to Ca2+i elevation. Previous results (Numann et al., 1987) showed that IA had a lower threshold (about -45 mV) than sustained currents (about -40 mV). By using low levels of depolarization (-40 mV), IA can be selectively activated, and the suppressive effect of Ca2+i on IA was confirmed on the kinetically isolated IA.(ABSTRACT TRUNCATED AT 250 WORDS)