Rapid hypertensinogenic effect of lead: studies in the spontaneously hypertensive rat.

Chronic lead exposure may cause hypertension in normotensive rats. This hypertensinogenic effect has been attributed to perturbations in the renin-angiotensin axis, the contractile response of the vascular smooth muscle, or the intracellular Ca2+ homeostasis as a consequence of the inhibition of Na(+)-K(+)-ATPase activity. In this study we examined the short-term effect of lead exposure on blood pressure, plasma renin activity, vascular contractility, and renal Na(+)-K(+)-ATPase activity and abundance in the spontaneously hypertensive rat. Our data indicate that modest lead exposure caused blood pressure elevation within two weeks in this rat strain that is genetically susceptible to the development of hypertension. This rapid blood pressure-elevating effect did not appear to depend on the mechanisms described in hypertension associated with more chronic lead exposure listed above. This acute model provides an additional approach to the study of lead-induced hypertension.     

High-efficiency stable gene transfection using chloroquine-treated Chinese hamster ovary cells

We describe a highly efficient stable gene transfection procedure for Chinese hamster ovary (CHO) cells using a modification of the calcium phosphate-DNA coprecipitation method. We have found that treatment of CHO cells with chloroquine increases the efficiency of gene transfer by up to 20-fold (from approx. 0.01% to approx. 0.2%) when transfection is done using the pSV2-neo plasmid. The optimized transfection procedure requires that CHO cells to be incubated with calcium phosphate-DNA coprecipitate and chloroquine (100 µM) for a total of 16 h. By using high-molecular-weight human genomic DNA as a DNA source for transfection, we show that this procedure is equally efficient for stably transferring a much larger gene, such as the 49-kb human hypoxanthine phosphoribosyltransferase gene.     

Immunization strategies for the production of rat monoclonal anti-idiotope antibodies

Anti-idiotypic antibodies are powerful reagents for the study of immunoregulation, and have potential interest as vaccines against tumors and infectious diseases. Three immunization strategies for the production of rat monoclonal anti-idiotope antibodies have been compared in this paper. Male Wistar rats were immunized i.p. and at multiple subcutaneous sites with 750 micrograms of purified monoclonal antibody against Plasmodium falciparum for three times and subsequently boosted by (1) intraperitoneal injection with 750 micrograms of the immunogen, (2) intravenous inoculation with 400 micrograms of the IgG, and (3) intrasplenic immunization with 200 micrograms of the idiotype. With the intraperitoneal boost method, the frequency of hybrids with anti-idiotope activity was 0.3-0.9% with 62.8-85.2% of the seeded wells containing hybrids. In the intravenous boost group, the percentage of hybrids demonstrating anti-idiotope activity increased to 11.0-13.3% with 80.2-97.9% of the hybrid efficiency. When immunized by the intrasplenic boost route, the frequency of anti-idiotope hybrids generated rose to 12.9-16.4% with 82.3-96.6% of the hybrid efficiency. There was no obvious effect of the boost immunizing methods on the generation of rat monoclonal anti-mouse IgG antibodies. These results indicated that the multiple-site immunization followed by intravenous or intrasplenic boost injection was an appropriate immunizing method for the production of monoclonal anti-idiotope antibodies.     

类黄酮物质抗动脉粥样硬化作用研究进展

人类植物性膳食成分中存在丰富的类黄酮物质，具有多种生物活性。近几年的流行病学研究和试验研究显示，类黄酮物质可以抑制动脉粥样硬化的发生与发展，从而降低心脑血管疾病的发生率和死亡率。本就类黄酮物质抗动脉粥样硬化的作用机制作一综述。     

Brain neurons and glial cells express Neu differentiation factor/heregulin: a survival factor for astrocytes.

Neu differentiation factor (NDF, also called heregulin) was isolated from mesenchymal cells on the basis of its ability to elevate phosphorylation of ErbB proteins. Earlier in situ hybridization analysis showed that NDF was transcribed predominantly in the central nervous system during embryonic development. To gain insights into the role of NDF in brain we analyzed its distribution by immunohistochemistry and in situ hybridization. Late-gestation (day 17) rat embryos displayed high NDF immunoreactivity in both motor (e.g., putamen) and limbic (e.g., septum) regions. Lower levels of the factor were exhibited by adult brain, except for the cerebellum, where NDF expression was increased postnatally. Both neurons and glial cells were identified by immunohistochemistry as NDF-producing cells (e.g., pyramidal neurons in the cerebral cortex and glial cells in the corpus callosum). By establishment of primary cultures of rat brain cells we confirmed that NDF was expressed in neurons as well as in astrocytes. In addition, by using such primary cultures we observed that NDF treatment exerted only a limited mitogenic effect, which was accompanied by significant acceleration of astrocyte maturation. Furthermore, long-term incubation with the factor specifically protected astrocytes from apoptosis, implying that NDF functions in brain as a survival and maturation factor for astrocytes.     

Fusiform posterior cerebral artery aneurysm treated with excision and end-to-end anastomosis. Case report

A case of a ruptured fusiform aneurysm of the posterior cerebral artery is reported. The aneurysm was excised and end-to-end anastomosis was carried out between the two ends of the posterior cerebral artery. There is no previous report of a posterior cerebral artery aneurysm treated with this technique. The pertinent literature is reviewed and the significance of this technique in the treatment of unclippable cerebral aneurysms is discussed.     

慢性乙肝患者血清细胞因子、乙肝病毒与肝纤维化的关系

目的：探讨慢性乙肝患血清细胞因子（TGF－β，TNF-α，IL-6，IL-8），乙肝病毒（HBV）对肝纤维化（HA，PCⅢ，C-Ⅳ，LN）的影响作用。方法：采用ELISA和RIA方法检测171例慢性乙肝患血清TGF－β，TNF-α，IL-6，IL-8，HLA，PCǚ，C-Ⅳ，LN的水平，HBV－DNA定量检测采用PCR方法。结果：慢性乙肝患血清TGF－β，TNF-α，IL-6，IL-8，HA，PCⅢ，C-Ⅳ，LN的含量均不同程度高于对照组，且随肝损害程度的加重而升高，与肝损害程度呈正相关关系（P＜0．05或P＜0．01）；须血清TGF－β1水平与血清HA，PCⅢ，C-Ⅳ，LN水平具有直线相关关系。HBV－DNA阳性组（Ⅱ组）均高于HBV－DNA阴性组（I组），且在慢性中，重度肝炎间差异显（P＜0．05）。结论：血清TGF－β，TNF-α，IL-6，IL-8参与慢性乙肝的发病机制及肝纤维化的形成，且与病毒复制的活跃程度相关。     

臀、会阴及其周围Ⅲ度烧伤的早期切痂治疗体会

目的　总结臀、会阴及其周围Ⅲ度烧伤的早期切痂治疗的经验。方法　对 3 2例臀、会阴Ⅲ度烧伤患者于伤后 3～ 7d内行切痂 ,嵌皮、大张皮片或皮瓣修复创面的资料进行回顾分析。结果　本组病例皮瓣、皮片大部分成活好 ,外观、功能恢复满意。结论　臀、会阴及周围Ⅲ度烧伤早期切痂治疗可缩短疗程 ,减少外观及功能障碍 ,近远期效果好