Lipid metabolism in pregnancy. II. Postheparin lipolytic activity and hypertriglyceridemia in the pregnant rat

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.     

Broad-beta disease versus endogenous hypertriglyceridemia: levels and lipid composition of chylomicrons and very low density lipoproteins during fat-free feeding and alimentary lipemia.

To assess the roles of endogenous and exogenous lipid in the production of the abnormal lipoprotein patterns characteristic of broad-beta desease (with a type IVIII lipoprotein pattern) and endogenous hypertriglyceridemia (with a type IV pattern), oral fat loads (50 g/M-2) were administered to six subjects with broad-beta disease and to eight with endogenous hypertriglyceridemia following at leat 72 hr of 0% fat, 85% carbohydrate isocaloric formula feeding. Total plasma and Sf greater than 400, 100-400, 60-100, 30-60, and 20-30 lipoprotein cholesterol, triglyceride, and phospholipid levels were measured at 0 hr, 6 hr (at or before the peak of alimentary lipemia), and 24 hr following the fat load. Following fat-free feeding the levels and composition of the endogenous Sf greater than 400 lipoproteins were similar in both disorders; whereas total Sf20-400, and most notably, Sf 30-60 and 20-30 levels were increased and enriched in cholesterol in the subjects with broad-beta disease.     

Perfusion of the cervical spinal cord in situ of adult rats using a perfluorocarbon emulsion

A method was developed for the perfusion of the cervical spinal cord of adult rats through the supplying arteries. A medium containing perfluorotributylamine as an oxygen carrier was used. The electrophysiological responsiveness was continuously monitored; pO₂, pCO₂, pH, Na⁺ and K⁺ were intermittently measured in the medium. The perfused cord maintained its responsiveness for more than 5 h. No changes in its structure became apparent in electron micrographs.     

Differences in tocopherol-lipid ratios in ARDS and non-ARDS patients

Plasma tocopherol, plasma total lipid levels and tocopherol-lipid ratio were measured every 6 h during 48 h in 12 critically ill patients and compared with those of a control group. The patients were divided into two groups. Group I comprised 6 critically ill patients with ARDS and group II comprised 6 severely ill patients without ARDS. The means for all observations of plasma tocopherol, total lipid levels and tocopherol-lipid ratio in groups I and II were significantly depressed relative to a control group (p<0.0001). The difference in the average tocopherol-lipid ratio between the three groups (p<0.0001) and between the groups I and II was statistically significant (p<0.0001). Our results indicated: (1) a decrease of vitamin E concentrations in the critically ill patients, particularly in ARDS patients; (2) the importance of the relationship between plasma tocopherol and plasma lipids levels in evaluating the deficiency in vitamin E which was evident in ARDS patients.     

In vivo evidence for alpha 2-adrenergic-dependent inhibition of lipid mobilization in the rabbit

Both alpha- and beta-agonists were infused i.v. in unanesthetized rabbits. The alpha-adrenergic effect on lipid mobilization was investigated by comparing the modifications of blood glycerol levels induced by clonidine (alpha 2-agonist) and amidephrine (alpha 1-agonist) alone or in combination with isoprenaline (beta-agonist). Clonidine (2 micrograms X kg-1 X min-1) was found to significantly reduce the basal or isoprenaline-stimulated glycerol levels whereas amidephrine (10 micrograms X kg-1 X min-1) was without any effect. Plasma IRI levels were also reduced by clonidine. The results suggest that the reduction of lipid mobilization produced by clonidine could have been the consequence of the stimulation of the alpha 2-adrenergic antilipolytic receptors previously shown to be present in isolated fat cell membranes.     

牛初乳脂质营养液用于严重烫伤大鼠的研究

目的：探索牛初乳脂质营养液用作烫伤病人营养增补剂的可能性。方法：分析了烫伤大鼠服用牛初乳脂质营养液第９天和２５天时血浆中脂溶性维生素、β－胡萝卜素、ＳＯＤ和ＬＰＯ的水平，作了烫伤动物的常规观察和存活率测定。结果：服用营养液能显著升高与生物体内抗氧化作用有关的脂溶性维生素，β－胡萝卜素和ＳＯＤ的水平，降低对生物体有害的ＬＰＯ的含量，明显提高烫伤动物的存活率。结论：该营养液可用作烫伤病人综合治疗的营养增补剂。     

家兔肾上腺素性心律失常时脂质过氧化的损伤及西米替丁的保护作用

采用硫代巴比妥酸（ＴＢＡ）显色法测定肾上腺素（ａｄｒｅｎａｌＡｄｒ）致室性心律失常（ＶＡ）后血浆及组织匀浆中脂质过氧化物（ＬＰＯ）的代谢产物丙二醛（ＭＤＡ）的含量，观察西米替丁（ｃｉｍｅｔｉｄｉｎｅＣｉｍ）对其含量的影响。结果发现Ａｄｒ诱发家兔ＶＡ后血浆及组织匀浆中ＭＤＡ含量明显增加，Ｃｉｍ３７．５ｍｇ／ｋｇｉｖ，能明显降低ＶＡ的发生率，推迟ＶＡ发作的时间，缩短其持续时间，并能显著抑制ＭＤＡ生成。提示Ａｄｒ致ＶＡ后体内脂质过氧化过程加强，Ｃｉｍ抗脂质过氧化可能与抗心律失常作用有关。     

Colour Doppler signal enhancement of intrarenal vasculature of the rabbit with Perflubron

The colour Doppler signal enhancement of the intrarenal vasculature of the kidney was studied after intravenous infusion of Perflubron. This enhancement was evaluated qualitatively and semi-quantitatively. Nine rabbits received 1 g/kg of a 100% w/v Perflubron emulsion [perfluorooctylbromide (PFOB), Alliance Pharmaceutical] intravenously. Then, two groups of 2 rabbits received 2 and 3 g/kg respectively, and 1 rabbit received 4 g/kg. The kidneys were imaged longitudinally on a colour Doppler unit with a 7.5 MHz transducer. Signal enhancement was evaluated semi-quantitatively by counting the levels of signal threshold that had to be subtracted to reproduce the baseline image. This measurement was performed 1, 3, 5, 10, 30, 45, 60, 90 and 120 min after infusion. We found that detection of very small vessels deep into the parenchyma was possible with Perflubron. In the group that received 1 g/kg Perflubron significant variations in signal enhancement were noted. The curve of mean signal enhancement showed a maximum Doppler signal at about 15 min, which slightly and progressively decreased during the next hour. With the 2, 3 and 4 g/kg doses, enhancement was constant and proportional to the infused dose. Perflubron emulsion allows significant Doppler enhancement on colour flow imaging, providing better visualisation of deep parenchymal small vessels. A dose of 1 g/kg seems adequate for this purpose.Correspondence to: N. Grenier     

抗氧化酶及脂质过氧化物在肾移植中的意义

检测同种异体肾移植患者的血清抗氧化酶，包括超氧化物歧化酶和谷胱甘肽过氧化物酶及脂质过氧化物的降解产物丙二醛的动态变化。以了解了其在肾缺血－再灌注损伤中的作用。     

ATP-MgCl_2对烫伤大鼠肠粘膜保护作用的实验观察

为研究 ATP-MgCl_2对创伤应激动物肠粘膜的保护作用,采用30%TBSAⅢ度烫伤大鼠模型,观察了腹腔注射 ATP-MgCl_2复合液对回肠粘膜丙二醛(MDA)含量及回肠组织形态学改变的影响。结果显示:烫伤后6～24小时,MDA 含量明显升高,并伴有形态学病理改变。经 ATP-MgCl_2注射治疗的大鼠伤后24小时内 MDA 含量维持于正常对照水平,且回肠粘膜病理改变减轻。提示:ATP-MgCl_2能够保护烫伤大鼠肠粘膜,其作用机理可能与降低肠粘膜的脂质过氧化反应有关。