小鼠尾动脉条应用于α肾上腺素受体激动剂、拮抗剂和钙拮抗剂的研究

近年内,国外一些学者已证明大鼠尾动脉存在突触后α_1和α_2肾上腺素受体并对此两种亚型的生理性质进行了研究、比较。目前,大鼠尾动脉条已广泛用于α_1及α_2受体激动剂和拮抗剂以及钙拮抗剂的生理和药理学研究。该方法需将动脉剪成螺旋条,制做比较复杂。为易于掌握,我们在制备方法上进行了改进。随后,设计和建立了小鼠尾动脉条实验模型。本文重点介绍小鼠尾动脉实验方法的优点及其应用范围,翼能在国内得到推广应用。     

柯萨奇-腺病毒受体在肾癌组织中的表达及意义

目的:研究柯萨奇-腺病毒受体(CAR)在肾癌组织中的表达及意义.方法:应用免疫组化SP法检测12例癌旁正常肾组织和48例肾细胞癌组织中CAR的表达.结果:12例正常肾组织全部表达CAR,48例肾细胞癌组织中31例无CAR表达.不同分级CAR表达率分别为Ⅰ级54.5%(12/22)、Ⅱ级23.5%(4/17)、Ⅲ级11.1%(1/9);不同分期CAR表达率分别为Ⅰ期57.9%(11/19)、Ⅱ期30.8%(4/13)、Ⅲ期18.2%(2/11)、Ⅳ期0(0/5).结论:在多数肾细胞癌组织中CAR基因表达丧失;CAR表达变化与肾癌的分级、分期相关,可以作为肾癌分化、转移的重要生物学指标.     

粉防己碱对体外培养大鼠脑皮层神经元损伤的保护作用

兴奋性氨基酸类神经毒剂与粉防己碱（Ｔｅｔ）共同作用于原代培养胎鼠大脑皮层神经元２４ｈ，发现１０－７，１０－６ｍｏｌ·Ｌ－１Ｔｅｔ明显降低谷氨酸（Ｇｌｕ），β－Ｎ－ｏｘａｌｙｌａｍｉｎｏ－Ｌ－ａｌａｎｉｎｅ（ＢＯＡＡ）和β－Ｎ－ｍｅｔｈｙｌａｍｉｎｏ－Ｌ－ａｌａｎｉｎｅ（ＢＭＡＡ）导致的培养液乳酸脱氢酶（ＬＤＨ）活性增高，细胞形态损害减轻，细胞数量增加。对ＮＭＤＡＡ介导的神经元损伤改变无影响。提示Ｔｅｔ对某些Ｇｌｕ类神经毒剂引起的胎鼠大脑皮层神经元损伤有一定保护作用，其机制可能是抑制细胞膜Ｎａ＋通道开放，阻止膜去极化而影响电压依赖性Ｃａ２＋通道启动。对ＮＭＤＡ受体可能亦有一定作用。     

The relationship between dorsal stream connections to the caudate and verbal fluency in Parkinson disease

Performance in verbal fluency tasks are widely used as a marker of cognitive impairment in Parkinson disease. However, the anatomical substrate of its impairment remains undetermined. Based on the dual-stream language model, we hypothesized cortical input to the subcortical circuitry would be a crucial determinant of fluency. We performed a retrospective study using individual whole-brain structural connectomes derived from 135 individuals with PD and assessed the relationship between white matter integrity and verbal fluency tasks. Controlling for multiple factors, including dysarthria, we observed higher integrity of dorsal stream-caudate connectivity was associated with better letter fluency. This preliminary study indicates the possible dissociation between dorsal and ventral stream connectivity and letter fluency in PD. In addition, it suggests a non-motor role of the frontostriatal fibers in letter fluency.

     

Bacterial Colonization of Bone Allografts: Establishment and Effects of Antibiotics

Background

Bone grafts are frequently used to supplement bone stock and to establish structural stability. However, graft-associated infection represents a challenging complication leading to increased patient morbidity and healthcare costs.

Questions/purposes

We therefore designed this study to (1) determine if increasing initial S. aureus inoculation of bone allograft results in a proportionate increase in colonization; (2) assess if antibiotics decrease colonization and if antibiotic tethering to allograft alters its ability to prevent bacterial colonization; and (3) determine if covalent modification alters the allograft topography or its biological properties.

Methods

Allograft bone and vancomycin-modified bone (VAN-bone) was challenged with different doses of S. aureus for times out to 24 hours in the presence or absence of solution vancomycin. Bacterial colonization was assessed by fluorescence, scanning electron microscopy (SEM), and by direct colony counting. Cell density and distribution of osteoblast-like cells on control and modified allograft were then compared.

Results

Bacterial attachment was apparent within 6 hours with colonization and biofilm formation increasing with time and dose. Solution vancomycin failed to prevent bacterial attachment whereas VAN-bone successfully resisted colonization. The allograft modification did not affect the attachment and distribution of osteoblast-like cells.

Conclusions

Allograft bone was readily colonized by S. aureus and covered by a biofilm with especially florid growth in natural topographic niches. Using a novel covalent modification, allograft bone was able to resist colonization by organisms while retaining the ability to allow adhesion of osteoblastic cells.

Clinical Relevance

Generation of allograft bone that can resist infection in vivo would be important in addressing one of the most challenging problems associated with the use of allograft, namely infection.     

Absence of DAZ gene mutations in cases of non-obstructed azoospermia

Sequenced-tagged site (STS) analysis of the Y chromosome long arm (Yq) of azoospermic males has identified a minimum common deleted region of several hundred kilobases in approximately 13% of cases. A candidate azoospermia gene, DAZ (deleted in azoospermia), has been isolated from this region. DAZ has also been shown to be absent in severely oligozoospermic males albeit at a much lower frequency. These data, although highly suggestive, do not constitute formal proof that DAZ actually plays a role in azoospermia, as no small intragenic deletions, rearrangements or point mutations in the gene have been found. In this study we report the screening of DNA from 168 azoospermic/oligospermic males for the presence of the DAZ gene. Deletions involving DAZ were detected in five out of 43 (11.6%) azoospermic males whereas none were found in the remaining 125 oligospermic patients. We present the genomic structure of the 5' end of the DAZ gene together with its sequence analysis in 30 non-obstructed azoospermic males. No mutations in DAZ were found in any of the patients sequenced. These data provide no formal proof that DAZ is AZF. Thus the possibility is still valid that another gene(s) mapping to the deletion interval may be responsible for, or contribute to, the observed phenotypes. Alternatively, if DAZ is AZF, they suggest that the most frequent cause of gene inactivation is via large deletions possibly mobilized by Y chromosome repetitive sequences.