外显子和内含子的序列复杂性

引入了两个新的关于序列复杂性的测度,并以此为指标分析比较了结构基因序列中的外显子和内含子的复杂性差异。     

移居海拔3700m高原青年体质综合评价方法的研究

在海拔３７００ｍ高原选择５０名男性青年的体重、立定跳远、引体向上、仰卧起坐、６０ｍ和２０００ｍ跑速度６项指标进行高原移居青年体制综合评价方法的研究。通过用百分位法制定各项指标评分标准,以各项指标评分相加作为体质总分,并用各项指标的简单相关系数与多元逐步回归方程的标准化偏回归系数的乘积（贡献率）分配“权重”,建立综合评价总分的计算式：Ｙ＝０．０５Ｘ１＋０．１６（Ｘ４＋Ｘ６）＋０．２１（Ｘ２＋Ｘ３＋Ｘ     

Oxidation of prostacyclin and its analogs by three 15-hydroxyprostaglandin dehydrogenases

A study of the oxidation of prostacyclin and some of its analogs by three 15-hydroxyprostaglandin dehydrogenases was undertaken to determine the structural features of these compounds which might influence their rate of enzymatic inactivation. The effect of some structural changes seemed to be determined by the substrate specificity of individual enzymes. Other changes influenced the rate of oxidation by all three enzymes similarily. Among this latter group it was noted that a 15S hydroxyl group is necessary for oxidation to occur and that steric changes in the carboxy side chain and structural changes in the epoxy ring have a greater effect on the affinity of the substrate for the enzyme than on its maximum rate of oxidation. Certain analogs of prostacyclin are not substrates for one or more of the enzymes tested. Of these, (5S)-9-deoxy-5,9 alpha-epoxy-PGF1 and its methyl ester are potent inhibitors of only the placental enzyme---an interesting case of apparent selective metabolic regulation.     

Adriamycin effects on transplasma membrane redox functions in porcine neutrophils

Transplasma membrane electron transport, as assayed by external ferricyanide reduction, has been related to control of growth and hormone response of cells. Elicitor-stimulated transmembrane NADPH oxidase is important for bacteriocidal superoxide production by neutrophils. Since adriamycin is myelosuppressive and can stimulate superoxide production, its effects on the two redox systems of porcine neutrophil plasma membranes were compared. Adriamycin inhibits transplasma membrane ferricyanide and stimulates superoxide production activated by phorbol myristate acetate (PMA). Ferricyanide reduction in PMA-treated cells becomes resistant to inhibition by adriamycin. These results provide evidence for an independent effect of adriamycin on transmembrane ferricyanide reduction and on superoxide generation.     

Insulin secretion from a continuously subcultivable isolate derived from foetal bovine pancreata beta cells. I. Monolayer cultures.

Monolayer cultures have been derived from bovine embryonic pancreatic cells grown in medium CMRL-1969 supplemented with foetal calf serum. The isolate has been subcultivated up to 10 population doublings. Insulin secretion from the cells into the culture medium declined with increasing passages. Of several insulin secretagogues, glucagon was found to be effective in potentiating insulin release from the cultivated cells into the medium. Insulin secretion rose to approximately 600 μU/culture/day in the presence of glucagon as compared to an average of 10 μU/culture/day in the control. This may be the first demonstration of a beta cell line developed from bovine embryonic pancreas.     

6,9-deepoxy-6,9,-(phenylimino)-delta 6,8-prostaglandin I1, (U-60,257), a new inhibitor of leukotriene C and D synthesis: in vitro studies

Addition of the calcium inophore, A 23187, and cysteine to isolated mononuclear cells from rat peritoneal washings causes a marked increase in the formation of thromboxane B2 (TxB2) along with the formation of leukotrienes C and D (LT's). The formation of LT's in this system was inhibited by 6,9-deepoxy-6,9-(phenylimino)-delta 6,8-prostaglandin I1, U-60,257, or its methyl ester, U-56,467, (ID50 4.6 and 0.31 microM, respectively). There was no inhibition of TxB2 formation. By contrast, two structurally-related compounds, PGI2 and its stable analog, 6-beta-PGI1, did not affect the formation of either LT's or TxB2. The inhibition of LT formation by U-60,257 was rapidly reversed after removal of this compound from the cells. U-60,257 did not inhibit the cyclooxygenase of human polymorphonuclear leukocytes. Nor did it inhibit formation of 12-L-hydroxy-5,8,10,14-eicosatetraenoic acid (12-HETE) in human platelets. On the other hand, U-60,257 inhibited glutathione S-transferase activity of rat basophil leukemia cells (ID50, 37 microM), suggesting that this compound may inhibit the last step in LTC biosynthesis. In addition to inhibiting LT synthesis, U-60,257 also appears to be a competitive inhibitor of the action of LT on the guinea pig ileum, although this inhibition requires a higher drug concentration than those ordinarily encountered during assay for LT's in U-60,257-treated incubations.     

Fusion of phosphatidylserine and mixed phosphatidylserine-phosphatidylcholine vesicles Dependence on calcium concentration and temperature

Dynamic light scattering has been used to study the temperature dependence of Ca²⁺-induced fusion of phosphatidylserine vesicles and mixed vesicles containing phosphatidylserine and different phosphatidylcholines. The final vesicle size after Ca²⁺ and EDTA incubation serves as a measure of the extent of fusion. With phosphatidylserine vesicles, the extent of fusion shows a sharp maximum at an incubation temperature which depends on the Ca²⁺ concentration between 0.8 and 2 mM. The shift in the fusion peak temperature with Ca²⁺ concentration is similar to the typical shift in the phase transition temperature with divalent cation concentration in acidic phospholipids. The results suggest a direct correlation between the fusion peak temperature and the phase transition temperature in the presence of Ca²⁺ prior to fusion. With mixed vesicles containing up to 33% of a phosphatidylcholine in at least 2 mM Ca²⁺, the extent of fusion as a function of incubation temperature also shows a maximum. The fusion peak temperature is essentially independent of the quantity and type of phosphatidylcholine and the Ca²⁺ concentration, and identical to that with pure phosphatidylserine in excess Ca²⁺. The results imply that Ca²⁺-induced molecular segregation occurs first, and fusion subsequently takes place between pure phosphatidylserine domains.     

Metabolism of prostaglandins in spontaneously hypertensive rats: NAD"-dependent 15-hydroxyprostaglandin dehydrogenase activity is decreased in kidney and increased in lung.

Renal, pulmonary and gastric NAD⁺-dependent 15-hydroxyprostaglandin dehydrogenase activities were determined in both spontaneously hypertensive and normotensive rats at 6 and 12 weeks of age. Renal enzyme activity in hypertensive rats was only 30–40% of that present in normotensive controls at both ages. In contract, pulmonary enzyme activity in hypertensive animals was twice as active as that in normal controls. There was no significant difference in gastric enzyme activity. NAD⁺-dependent 9-hydroxyprostaglandin dehydrogenase activity, the enzyme responsible for the conversion of vasoinactive PGF metabolites to PGE metabolites, also failed to show any difference in two types of rat kidneys. The results indicate that, in hypertension, prostaglandin inactivation is impaired in kidney but is facilitated in lung.     

Effects of acute hypoxia on incorporation of [1-14C]arachidonic acid into glycerolipids of rat brain

The effects of 1 min of acute hypoxic treatment (1% O₂ in N₂) on incorporation of [1-¹⁴C]arachidonic acid into brain lipids of 16-day-old rats were investigated at 3, 6, and 12 min after intracerebral injection of the labeled fatty acid. The hypoxic-hypoxia condition associated with convulsive seizures caused a decrease in the conversion of labeled arachidonate to its acyl-CoA as well as incorporation of the label into the brain phospholipids. Among the phospholipids, there was a specific decrease in the labeling of diacylglycerophosphoinositol (GPI), and this change was accompanied by an increase in labeling of the diacylglycerols. These results indicate that metabolism of the long-chain fatty acids and some glycero-lipids in brain are vulnerable to acute hypoxic treatment.