Differential changes of nicotinic receptors in the ratbrain following ibotenic acid and 192-IgG saporin lesionsof the nucleus basalis magnocellularis

The basal forebrain cholinergic neurons are implicated in the pathogenesis ofneurodegenerative diseases including Alzheimer^fn2s disease (AD). The nicotinic acetylcholine receptors (nAChRs) have been found to besignificantly afflicted in AD. To study the underlying mechanisms for dysfunction of the basalforebrain cholinergic neurons development of suitable animal models is warranted. In this studywe investigated the effects of bilateral lesions of the nucleus basalis magnocellularis on nAChRs inthe rat brain using the cholinergic system selective immunotoxin 192-IgG saporin andnon-selective excitotoxin ibotenic acid. Changes in nAChRs were measured by ³H-cytisineand ³H-epibatidine, two ligands with different selectivity for nAChRs subtypes. Inthe parietal cortex of ibotenic acid lesioned rates, the choline acetyltransferase activity (ChAT)was decreased by 24% while no changes were detected in the frontal cortex or hippocampus.Similarly, a 40% decrease was observed in the number of nAChRs labelled by ³H-cytisine,but not by ³H-epibatidine, in the parietal cortex, while no changes were found in thefrontal cortex or hippocampus. Although the 192-IgG saporin induced lesions reduced the ChATactivity in the frontal cortex, parietal cortex and hippocampus by 77, 50 and 21%, respectively, nochanges were observed in the number of nAChRs as studied by ³H-cytisine or ³H-epibatidine. The results indicate a difference in vulnerability of the cortical nAChRsubtypes to experimental lesions of the nucleus basalis magnocellularis. The findings in this studysuggest that a major portion of the nAChRs might be located on non-cholinergic neurons in thebrain.     

吡那地尔对高血压心脏结构和功能重构的影响

在等降压剂量下吡那地尔和赖诺普利可使４月龄自发性高血压大鼠的血压下降６．０￣８．０ｋＰａ，并接近同种属正常血压大刀瓣血压水平。     

呼出气氢测定试验对飞行人员乳糖酶缺乏症的研究

对66名汉族飞行人员进行乳糖呼出气氢测定试验,乳糖吸收不良的发生率为83.3％,其中乳糖不耐受者占34.6％;与一般汉族人群无明显差别。对10名确定为中度以上乳糖吸收不良的飞行人员进行250ml鲜牛奶的试验结果,有50％呼出气氢含量在正常范围,并无一例出现胃肠道症状。提示较长期食用牛奶未能使乳糖酶缺乏状态发生改变,但每日食用适量牛奶属合理营养。     

以循证医学的理念观察颈椎综合征的MRI图像

目的鉴于MRI对组织的高分辨性能,利用该图像观察颈椎综合征患者的椎管外组织的病理状况.方法54例患者,其中男30例,女24例,分为2组.观察组44例颈椎综合征患者,对照组10例颈部外伤和三叉神经痛患者.通过常规的MRI矢状位及横轴位颈椎图像,比较两组软组织增生情况.结果与结论在颈椎综合征MRI的颈椎及上段胸椎棘突后侧,均可观察到不同程度的慢性纤维性变化,与对照组比较,有可比性.提示临床上颈椎综合征多与颈肩区筋膜炎、棘突炎相关,属于无菌性炎症,其慢性阶段,局部发生了纤维增生性改变.建议在观察分析此种病症的颈椎骨质及椎间盘改变的同时,宜重视棘突后侧的纤维性变化,有利于病理病因的研究.     

脚压测量用传感器

本文讨论了用于脚压测量的四类压力传感器，电阻式传感器、压电式传感器，光电式传感器，电容式传感器介绍了其结构、原理和特点，并分析了几种典型的测量接口电路。     

Detection of T cells responsive to a vascular growth factor in rheumatoid arthritis

The primary lesion in rheumatoid arthritis (RA) is a destructive synovitis characterized by proliferation of endothelial cells, fibroblasts, and vascular smooth muscle cells, and with perivascular lymphocyte aggregates. A nonhematopoietic growth factor, acidic fibroblast growth factor (aFGF), may induce many of the biological features found in rheumatoid synovium, including T cell activation. To determine if aFGF-responsive T cells are increased in RA, we developed an assay to measure the frequency of peripheral blood T cells that are costimulated by aFGF. The data indicate that the frequency of aFGF-responsive T cells is increased in RA and may change with disease activity and treatment.     

Temporal variability of Cryptosporidium in the Chesapeake Bay

Although Cryptosporidium has been found worldwide in molluscan shellfish from waters contaminated with human and animal feces, little or no related environmental data have been obtained. In the present study, oysters ( Crassostrea virginica) were collected eight times over 3 years from seven sites in the Chesapeake Bay or its tributaries, with accompanying data on water temperature, salinity, rainfall, and streamflow. Oyster gill washings were examined by immunofluorescence microscopy for Cryptosporidium oocysts. Of 1,590 oysters collected, 19.6% had detectable oocysts. Of 53 collections, oocysts were detected 81% of the time. The time when the greatest percentage of oysters at most sites had detectable oocysts coincided with the time of greatest weekly and monthly rainfall, greatest streamflow into the Bay, and lowest water temperatures. In 28% of 53 collections, C. parvum genotypes 1 and 2 and C. baileyi were identified by PCR and gene sequencing. Oocyst infectivity was confirmed from 37.5% of 40 collections by initiating C. parvum genotype 2 infections in mice.     

Endocarditis with ruptured cerebral aneurysm caused by Cardiobacterium valvarum sp. nov

A fastidious gram-negative bacterium was isolated from the blood of a 37-year-old man who had insidious endocarditis with a sudden rupture of a cerebral aneurysm. Characterization of the organism through phylogenetic and phenotypic analyses revealed a novel species of Cardiobacterium, for which the name Cardiobacterium valvarum sp. nov. is proposed. C. valvarum will supplement the current sole species Cardiobacterium hominis, a known cause of endocarditis. Surgeries and antibiotic treatment cured the patient's infection and associated complications. During cardiac surgery, a congenital bicuspid aortic valve was found to be the predisposing factor for his endocarditis.     

cagA-Positive Helicobacter pylori Populations in China and The Netherlands Are Distinct

The aim of this research was to study whether and to what extent Chinese cagA-positive Helicobacter pylori isolates differ from those in The Netherlands. Analysis of random amplified polymorphic DNA (RAPD)-PCR-assessed DNA fingerprints of chromosomal DNA of 24 cagA-positive H. pylori isolates from Dutch (n = 12) and Chinese (n = 10) patients yielded the absence of clustering. Based on comparison of the sequence of a 243-nucleotide part of cagA, the Dutch (group I) and Chinese (group II) H. pylori isolates formed two separate branches with high confidence limits in the phylogenetic tree. These two clusters were not observed when the sequence of a 240-bp part of glmM was used in the comparison. The number of nonsynonymous substitutions was much higher in cagA than in glmM, indicating positive selection. The average levels of divergence of cagA at the nucleotide and protein levels between group I and II isolates were found to be high, 13.3 and 17.9%, respectively. Possibly, the pathogenicity island (PAI) that has been integrated into the chromosome of the ancestor of H. pylori now circulating in China contained a different cagA than the PAI that has been integrated into the chromosome of the ancestor of H. pylori now circulating in The Netherlands. We conclude that in China and The Netherlands, two distinct cagA-positive H. pylori populations are circulating.