ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00788.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Lactate is the predominant gluconeogenic precursor in man. To determine the dose‐response relationships between plasma lactate concentration and rates of lactate incorporation in plasma glucose (lactate gluconeogenesis, LGN), we infused 17 normal volunteers with sodium lactate for 180 min at rates ranging from 6 to 40 γmol kg‐1min‐1and measured [U‐14C]lactate incorporation into plasma glucose, as well as rates of lactate and glucose appearance in plasma. With the highest lactate infusions, plasma lactate increased up to 7 mM (compared to 1.1±0.13 mM during control sodium bicarbonate infusions, n=10) and LGN averaged 4.73 ± 0.23 μmol kg‐1min‐1(compared to 1.57 ± 0.26 μmol kg‐1min‐lin bicarbonate control experiments,P<0.001). The data relating plasma lactate concentration to LGN best fit a sigmoidal curve which plateaued at plasma lactate concentrations of approximately 6 mM and yielded an ED50of 2.04 ± 0.20 (SD) mM and a Vmax (6.25±1.2) (SD) (mUmol kg‐1min‐1). The sum of the basal rate of lactate appearance and the rate of lactate infusion was not significantly different from the overall rates of lactate appearance during the lactate infusions (35.8±2.2 vs. 34.8±2.9 μmol kg‐1min‐1, P = 0.23). Thus, our results support the view that infusion of exogenous lactate does not suppress endog

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00789.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Anti‐gp41 antibody affinity was investigated prospectively in 25 patients with asymptomatic and symptomatic HIV‐1 infection for a period of 9–42 months. Major differences in the processs of immune response maturation towards gp41 were observed among individual subjects, however, antibody affinity increased with time in all examined persons including patients with AIDS. Anti‐gp41 affinity values were found to reflect both the duration and the clinical stage of HIV i

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00790.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Esterified cholesterol transfer (ECT) from high density lipoproteins (HDL) to very low (VLDL) and low density lipoproteins (LDL) may be abnormal in situations at high risk for atherosclerosis. It has been shown to increase in insulin‐dependent diabetes and to decrease in non‐insulin‐dependent diabetes (NIDD). Since the net transfer of esterified cholesterol (EC) results from a bidirectional exchange between HDL and VLDL/LDL, we developed a transfer assay specifically designed to measure the unidirectional transfer of EC from HDL to lipid emulsions according to first‐order kinetics. Our results show that in NIDD the rate constant of HDL‐dependent ECT is decreased by 30% by comparison with control subjects. Analysis of HDL composition revealed that, in both groups, HDL‐dependent ECT was positively correlated with the free cholesterol/phospholipid ratio (r = 0.94;P<0.001) and negatively correlated with the triglycer‐ide/EC ratio (r=‐0.85; P<0.001). It is concluded that, besides the known defect of acceptor lipoproteins, the abnormality of ECT in NIDD is also caused by a decreased ability of HDL to act as an EC donor, presumably because of a change in composition. In addition, our work shows that the amount of EC lost by HDL during the reaction transfer is counterbalanced by a reciprocal equimolar transfer of

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00791.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.We have carried out intravenous glucose tolerance tests with measurement of plasma glucose, insulin and C‐peptide concentrations on 66 premeno‐pausal and 92 postmenopausal non‐obese Caucasian women. After adjustment for the effects of a number of possible confounding variables, including age and body mass index, there was little difference between pre and postmenopausal women in glucose and insulin concentrations either fasting or in response to intravenous glucose. Mathematical modelling analysis of the resultant plasma concentration profiles was used to obtain measures of insulin sensitivity, secretion and elimination, and non‐insulin dependent glucose disposal. We found reciprocal differences in mean insulin sensitivity (increased by 50%) and non‐insulin dependent glucose disposal (decreased by 30%). Plasma C‐peptide response and pancreatic insulin secretion were markedly lower in the postmenopausal group (‐ 35% and ‐50% respectively). However, the rate constant for insulin elimination was also lower in these women. As a result, intravenous glucose tolerance test plasma insulin concentrations were not significantly different between the two groups. We conclude that, despite the occurrence of little or no variation in plasma glucose and insulin concentrations, the menopause is associated with significant changes in ins

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00792.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Monocyte adhesion to endothelium appearing determinant in atherosclerosis, the possibility that circulating monocytes have an increase of their adherence on endothelial cells were investigated in patients with atherosclerosis. The adherence of circulating monocytes on endothelial cell monolayers was determined in 26 patients with atherosclerosis (age 59 ± 4), and 25 healthy individuals (age 55 ± 4). No difference of monocyte adherence was observed between the two groups (18.8±13.8% vs 19.2±13.4%), or following atherosclerosis severity. However monocyte adherence appeared positively correlated to smoking habits (r = 0–34, P<0.02) and fibrinogen level (r = 0.31, P<0.03), and negatively to the degree of plasmatic LDL oxidation (r=‐0.28,P<0.05). These results suggest that the adherence of monocytes to endothelial cells is not increased in atherosclerosis, but enhanced by risk factors. A weak plasmatic LDL oxydation could inhibit monocyte a

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00793.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Acute hypoglycaemia enhances intestinal sugar uptake but the mechanisms involved are unknown. Results from the present study show increased galactose movement across the brush border and basolateral membranes of isolated upper, but not mid‐villus, jejunal enterocytes 45 min after intravenous administration of insulin to rats at a level which reduced by half plasma glucose concentration. Incubation of upper villus cells from uninjected animals with insulin (100 mU ml‐1) for 40 min was without effect on brush border or basolateral sugar transport. Insulin treatment of rats did not affect glucose uptake by brush border vesicles prepared from upper villus cells when the process was driven by an inwardly directed 100 mM sodium thiocyanate gradient. In contrast, glucose uptake using a 100 mM inwardly directed sodium chloride gradient was reduced by 49% following hypoglycaemia. It is concluded that the enhanced sugar uptake following insulin hypoglycaemia involves both brush border and basolateral membranes of only the most mature villus cells at the villus tip. Upregulation of Na+‐sugar cotransport at the brush border is best explained by an increased electrochemical driving force for Na+‐sugar cotransport rather than increased numbers of transporters. The transport response is not due to a direct effect of insulin on the enterocyte and the possible systemic factors involved are di

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00794.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Epidemiological studies have consistently shown an apparent protective effect of moderate alcohol consumption on coronary artery disease (CAD). This has been considered to be due to the rise in the high‐density cholesterol lipoprotein (HDL‐cholesterol). Since the response of the HDL‐subfractions to moderate or heavy dose of alcohol is less clear, we now compared the high‐density lipoprotein cholesterol status between groups consuming different amounts of alcohol. In this population‐based survey serum total high‐density lipoprotein cholesterol and its HDL2and HDL3subfractions were blindly compared between 264 consecutive middle‐aged men (37 teetotallers, 137 moderate drinkers, 90 heavy drinkers) participating in a voluntary health screening and 104 male alcoholics.Alcohol consumption correlated significantly (P<0.001) with total HDL‐cholesterol, HDL2, HDL3when all subjects (n= 368) were included but the correlation disappeared when alcoholics were excluded (n = 264). In comparison with teetotallers, alcoholics had significantly higher total HDL‐cholesterol, HDL2and HDL3values (P<0.001). Moderate or heavy intake of alcohol had no effect on HDL2but increased the HDL3‐‐fraction.If the protective effect of moderate alcohol consumption is mediated by high‐density lipoprotein, it may not be accounted for by changes in the HDL2‐‐fraction. The observed increases in the concentration of the HDL3‐‐fraction, however, suggest that this subfraction may not be inert with respect to coronary disease and could possibly have

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00795.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.The response of plasma triglyceride and of the high density lipoprotein (HDL) system to a triglyceride lowering diet and to a bezafibrate was compared in a group of 24 human subjects with mild to moderate hypertriglyceridaemia and low HDL‐cholesterol levels. Post‐heparin plasma lipoprotein (LPL) and hepatic (HL) lipase activities were determined before the initiation of the study and at the end of the diet (12 weeks) and bezafibrate (12 weeks) periods. HDL structure and composition were determined on a zonal centrifugation system at the end of the diet and bezafibrate periods. Diet caused a 9–20% reduction of plasma triglycerides but there was no change in LPL, HL or HDL levels. The individual responses between plasma triglycerides and HDL cholesterol levels however were highly correlated (r = 0.60 to 0.78). Combined diet plus bezafibrate therapy caused a further 38% decrease of plasma triglycerides with a 28% increase of HDL‐cholesterol and a 47% increase of LPL activity. HDL3density decreased and the contribution of cholesteryl ester to the HDL mass was increased while the contribution of proteins and triglycerides decreased. In the majority of the subjects (61%) HDL cholesterol levels increased by 20% or more and in these subjects the change of HDL was highly correlated with the change of the LPL/HL ratio (r = 0.74) but not with the change of the plasma triglyceride levels. In the remaining subjects (39%), HDL cholesterol levels remained unchanged or increased by less than 20%. The change of HDL cholesterol levels in these subjects was unrelated to the decrease of plasma triglycerides or the change of post‐heparin lipase activities. It is suggested that during triglyceride‐lowering diets HDL levels change in relation to the reduction of plasma triglycerides due to a decreased cholesteryl ester transfer between lipopro‐teins (a weak effect) while during combined diet plus bezafibrate therapy, an additional strong effect on HDL due to the increased LPL activity exists at least in the majority of

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00796.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Inhalation of nitric oxide (NO), an endoge‐neous vasodilator, was recently described to reduce pulmonary vascular resistance, and to improve arterial oxygenation by selective vasodilation of ventilated areas in patients with adult respiratory distress syndrome (ARDS). We describe the time‐course and dose‐response of initial short‐term NO inhalation in 12 patients with ARDS. Enhanced oxygenation was achieved within 1–2 min after starting NO inhalation; after inhalation, baseline conditions were re‐achieved within 5–8 min. Effective doses for improvement of oxygenation [baseline: PaO2= 10.2±2.5 KPa (76.4±18.7 mmHg)] were low: ED50was about 100 ppb—a concentration similar to the atmosphere. NO doses of more than 10 ppm [10 ppm NO: PaO2=17.3 ± 3.3 KPa (129.4 ± 25.1 mmHg)] re‐worsen the arterial oxygenation. The ED50for reduction of mean pulmonary artery pressure was 2–3 ppm. This indicates that inhalation of NO for improvement of oxygenation in severe ARDS should be performed using lower doses, with lower ris

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1993.tb00797.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY