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961.
We evaluated serum total-, LDL-, HDL-, cholesterol and triglycerides in 858 women. Sixty-seven were in premenopause, 307 in perimenopause, 326 in spontaneous menopause, and 158 women underwent hysterectomy. Of these, 101 had bilateral ovariectomy, 24 with unilateral ovariectomy and 33 with retention of both ovaries. After correcting for chronological age and body mass index by variance analysis, it was found that total-, LDL- and HDL-cholesterol significantly increased during menopause without changes in the total cholesterol/HDL-cholesterol, LDL-cholesterol/HDL-cholesterol and triglycerides/HDL-cholesterol ratio. The changes gradually occurred during the months preceding spontaneous cessation of menses. Atherogenic metabolic risk (as relative risk of high total and LDL-cholesterol, estimated by logistic regression analysis) significantly increased in all groups of women in reference to premenopause. The risk observed in surgical menopause with bilateral ovariectomy was higher than in spontaneous menopause, and conservation of ovaries in hysterectomized women seems to protect only partially against such an increase.  相似文献   
962.
在电脱盐动态模拟装置上研究了温度和电场强度对电脱盐效果的影响。结果表明,电脱盐过程中的温度和电场强度都存在最佳值;温度主要是通过影响原油的粘度来改变水滴沉降速度的,油水密度差的影响较小;温度和场强不是独立变量,随着温度的升高,最佳场强值将降低。  相似文献   
963.
马蔺子甲素乳剂的分光光度测定   总被引:6,自引:0,他引:6  
利用马蔺子甲素的醌型结构与2,4-二硝基苯肼反应生成马蔺子甲素双-2,4-二硝基苯腙,再在二乙醇胺-吡啶溶液中形成相应的共轭离子,用分光光度法测定马蔺子甲素乳剂的含量,可使其最大吸收波长由269nm转移到632nm,避开了乳剂中豆油和卵磷脂对其含量测定的干扰。本法平均回收率为99.48%,变异系数为0.23%。  相似文献   
964.
Zusammenfassung Nach zahlreichen klinischen, elektromyographischen, bioptisch-lichtmikroskopischen und autoptischen Erfahrungen ist auch das periphere Nervensystem häufig am Krankheitsprozeß der Ataxia teleangiectatica (AT) beteiligt. Elektronenmikroskopisch zeigen Suralisbiopsien eines Brüderpaares mit AT eine Speicherung diverser Lipidartikel in Schwannschen Zellen bemarkter und unbemarkter Nervenzellen sowie leichte axonale Degenerationen. Diese Befunde bestätigen weitgehend die Ergebnisse, die Gardner u. Goodman (1969) bei der bisher einzigen derartigen Biopsie beschrieben. Gestützt auf die dargestellten morphologischen Beobachtungen wird eine enzymatische Störung des Lipidmetabolismus oder eine lysosomale Fermentanomalie als pathogenetischer Faktor der AT diskutiert.
Ataxia teleangiectasia; electron microscopic study of two nerve biopsies
Summary Neumerous clinical, electromyographic and morphological findings are indicating that the peripheral nerve is often involved in ataxia teleangiectasia (AT). Electron micrographs of sural nerves of two brothers with AT reveal various lipid-containing particles within Schwann cells of myelinated fibers and, in addition, a slight axonal degeneration. These results confirm the findings of Gardner and Goodman (1969) in the only biopsy to be reported to date. The morphological alterations demonstrated raise the question whether an enzymatic error of lipid metabolism or a lysosomal enzyme anomaly represent a pathogenetic factor in AT.
  相似文献   
965.
Data presented here indicate that iron exposure exacerbates the changes in the glutathione status of the liver cell and the lipid peroxidative response of the tissue induced by acute ethanol intoxication. In these conditions, additivity in lipid peroxidation was found to occur either when the process was estimated by hepatic malondialdehyde formation, as well as by measurements of the biliary malondialdehyde release in the anesthetized rat and by the antioxidant-sensitive respiration in the perfused rat liver, procedures which are non-invasive for the tissue.  相似文献   
966.
E S Rowe 《Alcohol》1985,2(1):173-176
We have been systematically investigating the physical interactions of alcohols with synthetic lipids in order to elucidate the mechanisms of alcohol intoxication. It has previously been shown that the effects of ethanol on the phase transition temperatures of saturated chain phosphatidylcholines (PC's) are biphasic [11]. The secondary high concentration effect has recently been shown to be due to a transition to a new completely interdigitated state [16]. In the present report we have investigated the influence of the chain length of the alcohol on the induction of this interdigitated state. We demonstrate that all three alcohols have a biphasic effect on the transition temperature of PC, and the comparison of the concentration dependencies of this effect for the three alcohols provides some insight into the possible mechanism of the transition. The potential biological importance of this secondary alcohol-membrane interaction is discussed.  相似文献   
967.
The binding profile of [3H]8-hydroxy-2-(di-N-propylamino)-tetralin ([3H]8-OH-DPAT) to serotonin1A (5-HT1A) sites in rat hippocampal, frontocortical and striatal membranes has been compared. In these regions, [3H]8-OH-DPAT labels both a high and a low-affinity binding sites; the affinity values for each of the two sites are comparable in the different brain regions, but have different maximal capacity. By modifying the experimental conditions in a series of hippocampal membrane preparations, reciprocal changes in the proportion of the two sites were observed suggesting that they represent, at least in this region, different conformations or affinity states of a single receptor protein. In contrast to the lower affinity states, it appears that the high-affinity state is stabilized by coupling with a G-protein. Evidence supporting this statement is provided by addition of the guanine nucleotide Gpp(NH)p, breakage of labile disulfide bonds using N-ethylmaleimide and increasing membrane rigidity with ascorbate-induced lipid peroxidation, conditions which all reduced the density of receptors in the high-affinity state. Moreover, the high-affinity state appears to be stabilized at the expense of the lower affinity state in the presence of Mn2+. On the other hand, a complete shift to the low-affinity binding state was observed after a 24 h in vivo treatment with inhibitors of monoamine oxidase A (phenelzine or clorgyline) but not of monamine oxidase B (deprenyl). This disappearance of the high-affinity state with a concomitant increase in the binding capacity of the low-affinity state was reproduced by inhibiting monoamine oxidase A in vitro, as well as by reducing preincubation washout periods. Also, competitors of the [3H]8-OH-DPAT binding site, such as serotonin and unlabelled 8-OH-DPAT, display two affinity states while others like (±)-propranolol, tryptamine and spiperone recognize a single affinity component. These results suggest that the 5-HT1A binding site may exhibit at least two different affinity states depending upon its microenvironment and the intrinsic activity of the ligand used.  相似文献   
968.
969.
An optical density value ?0.15 at A650 nm of amniotic fluid obtained through transabdominal amniocentesis from a high risk obstetrical population, which excluded diabetes mellitus, isoimmunization, and amniotic fluid infection, correlated 98.6% with a mature lecithin to sphingomyelin ratio (LS) ? 2.0% and 41.6% with the presence of phosphatidylglycerol (PG). The corresponding false positive rates were 1.4% and 16.8%, respectively. In 30 infants delivered within 48 h of testing, A650 nm ?0.15 correlated 100% with absence of respiratory distress syndrome. A650 nm is not recommended for Rhesus immunized gestations, diabetic pregnancies and amniotic fluid infection due to a high false positive rate with A650 nm compared to LS and PG.  相似文献   
970.
Plasma postheparin lipolytic activity (PHLA) has been measured in rat pregnancy to qualitatively assess mechanisms of triglyceride removal from the circulation. This assessment can be made if the larger plasma volume of pregnancy is considered. A supramaximal dose of heparin avoids dilution of the heparin stimulus to PHLA release. Dilution of the released PHLA is corrected using measurements of plasma volume. In addition, no evidence of circulating inhibitors is present, and timing of PHLA appearance is unaffected by pregnancy. Prior studies of postheparin lipolytic activity in human pregnancy have not taken the effect of plasma volume into account and must therefore be reconsidered in light of the present results. We observed a biphasic in PHLA over the course of gestation. Levels were increased in midgestation (day 12), declined to normal by day 19, and fell rapidly to one-half of control by day 21. Assuming a functional role for the triglyceride lipases represented in PHLA, the data suggest the following hypothesis: triglyceride removal is increased or normal for the greater part of gestation and is decreased only at term. If this hypothesis proves true, the hypertriglyceridemia of pregnancy should be due largely to overproduction, with decreased removal contributing only near term.  相似文献   
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