Negative control by Sandostatin on pancreatic and duodenal growth: a possible implication of insulin-like growth factor I

This study was undertaken to evaluate the effects of Sandostatin, a potent somatostatin analogue, on pancreatic and intestinal growth and plasma and pancreatic levels of insulin-like growth factor I, a known growth factor. Rats weighing 320-330 g, equipped with an intravenous cannula were infused with either bovine serum albumin or Sandostatin at a dose of 5 micrograms kg-1 h-1 for 7 days. Sandostatin caused significant reductions in pancreatic and intestinal weights accompanied by decreases in total DNA, RNA in both organs and total protein in the intestine while total pancreatic enzymes were increased. Plasma cholecystokinin and insulin-like growth factor I were reduced whereas total insulin-like growth factor I pancreatic content was increased. It is suggested that Sandostatin may reduce growth of these two organs by decreasing cholecystokinin and insulin-like growth factor release and their specific effects at the pancreatic and duodenal cellular level.     

冲击波负压对大鼠肺致伤效应的初步观察

观察了不同的冲击波负压峰值对大鼠肺的影响。各种条件下的冲击波负压值可由负压发生装置来模拟调节,这种装置可满足化爆、核爆和爆炸性减压下负压参数的一般要求,参数稳定,重复性好。冲击波负压峰值范围为-13～-90kPa,下降时间为1～90ms,持续时间为14～2 000ms。6组Wistar系大鼠,分别暴露在-47.2～-84.0kPa的冲击波负压环境中,伤后立即解剖动物,重点观察肺伤情。实验结果显示,在上述冲击波负压环境中,肺可出现从无伤至极重度伤;出血、充血以及肺表面压痕酷似肺冲击伤的病理表现。随着冲击波负压峰值的变化,各组肺伤情亦随着变化,冲击波负压峰值(△P)和减压倍数(P_i/P_a)分别与肺出血面积和动物死亡率相关显著或非常显著。本实验提示,一定条件下的冲击波负压具有明显的致伤作用,且伤情变化范围与超压所致肺伤情变化范围相同,超压和冲击波负压在一定条件下可通过伤情指标等效。     

Immunoelectron microscopic double labeling of alkaline phosphatase and penicillinase with colloidal gold in frozen thin sections of Bacillus licheniformis 749/C.

The subcellular distribution of alkaline phosphatase and penicillinase was determined by double labeling frozen thin sections of Bacillus licheniformis 749/C with colloidal gold-immunoglobulin G (IgG). Antipenicillinase and anti-alkaline phosphatase antibodies were used to prepare complexes with 5- and 15-nm colloidal gold particles, respectively. The character of the labeling of membrane-bound alkaline phosphatase and penicillinase was different: the immunolabels for alkaline phosphatase (15-nm particles) were bound to a few sites at the inner surface of the plasma membrane, and the gold particles formed clusters of various sizes at the binding sites; the immunolabels for penicillinase (5-nm particles), on the other hand, were bound to the plasma membrane in a dispersed and random fashion. In the cytoplasm, immunolabels for both proteins were distributed randomly, and the character of their binding was similar. The labeling was specific: pretreating the frozen thin sections with different concentrations of anti-alkaline phosphatase or penicillinase blocked the binding of the immunolabel prepared with the same antibody. Binding could be fully blocked by pretreatment with 800 micrograms of either antibody per ml.     

鄱阳湖水生植被

本文列出了鄱阳湖98种水生维管束植物的名录,叙述了水生植被的分布。鄱阳湖水生植被面积为2262平方公里,占全湖总面积的80．8％。湖中植被呈不规则环带状分布,并可划分为湿生、挺水、浮叶和沉水4个植物带,9个主要植物群丛。并研究了鄱阳湖水生植被的演变及发展趋势和湖水位的季节性变化对植被的影响。     

Retroviral expression of alternatively spliced forms of rat fibronectin

We describe the construction in retroviral vectors and the expression of recombinant rat fibronectin (FN) cDNAs corresponding with the various alternatively spliced forms of FN. In NIH 3T3 cells, the exogenous rat FN subunits are efficiently secreted as heterodimers with endogenous mouse subunits. In contrast, in lymphoid WEHI231 cells, there is no endogenous FN synthesis and the recombinant FNs are secreted and can be purified as homogeneous proteins. We show that the purified recombinant FNs are biochemically and biologically functional. In basic assays for adhesion, spreading, cytoskeletal organization, and migration using various established adherent cell lines, different forms of FNs containing the different alternatively spliced segments show no marked differences in activity. We have used these recombinant FNs to investigate three systems in which earlier results had suggested potential differences between different forms of FN. First, all forms tested appear equally active in restoring normal morphology to a transformed cell line. Second, we detect minor differences in their ability to assemble into preexisting extracellular matrices. Finally, we report that only those forms of FN that contain the V segment will promote the spreading of a lymphoid cell line indicating that this segment confers additional biological functions for some cell types, a result that confirms and extends earlier data. These homogeneous, biologically active recombinant FNs will allow further studies of the role of the alternatively spliced segments of FN.     

L7811鼠腹水肿瘤细胞^31P核磁共振的研究

用~(31)P核磁共振技术(~(31)P-NMR)研究了L_(7811)鼠腹水肿瘤细胞和615系鼠胸腺细胞(正常对照细胞)。结果发现在肿瘤晚期阶段,L_(7811)腹水肿瘤细胞的含磷化合物未进入完全不活跃状态。此外,腹水肿瘤细胞的磷脂组成与含量亦有明显改变。因此,~(31)P-NMR谱可做为观察肿瘤细胞内能量生成和某些磷脂合成宏观动态过程的一项参考指标。     

Lipid Composition in Scrapie-Infected Mouse Brain: Prion Infection Increases the Levels of Dolichyl Phosphate and Ubiquinone

Abstract: The neutral and phospholipid composition of mouse brain infected with scrapie prions was investigated. During the later stages of this disease, the level of dolichol decreased by 30% whereas the level of dolichyl phosphate increased by 30%. In terminally ill mice, there was also a 2.5-fold increase in both total ubiquinone and its reduced form. Furthermore, α-tocopherol was elevated at this stage by 50%. In contrast, no changes were observed in phospholipid amount, in phospholipid composition, and in phosphatidylethanolamine plasmalogen content during the entire disease process. The fatty acid and aldehyde composition of individual phospholipids remained unaltered as well. No modifications could be detected in cholesterol content. Thus, the majority of membrane lipids in scrapie-infected mouse brain are modified in neither quantity nor structure, but specific changes occur to a few polyisoprenoid lipids. This specificity indicates that, although prions accumulate in lysosomes, the infection process is not associated with a general membrane destruction caused by lysosomal enzyme leakage.     

PRIMARY STRUCTURE OF ALLATOSTATIN 4, A NEVROPEPTIDE INHIBITOR OF JUVENILE HORMONE SYNTHESIS

Abstract Isolation and identification of allatostatin 4 (AST 4) from crude brain extracts of female Diploptera punctata are described. Synthetic analogues of allatostatin 4 truncated from the N-terminal were evaluated to gain some knowledge of structure-activity correlation. AST 4 reversibly inhibits the biosynthesis of JH in vitro . AST 4 has the following sequence: Asp-Arg-Leu-Tyr-Ser-Phe-Gly-Leu-NH₂. This neurohormone (AST 4) has no sequence similarity with any known neuropeptide from other organisms. Synthetic AST 4 as well as truncation fragments, including two with the five and six amino acids terminal residues deleted showed in vitro activity distinguishable from that of the native allatostatin.