摘要:

Abstract.In addition to LDL, Lp(a) can be quantitavely eliminated from plasma in an extracorporeal LDL‐apheresis procedure based on precipitation with heparin at pH 5.12. The rates of return of postapheresis Lp(a) and LDL‐cholesterol concentrations to baseline levels were investigated in six individuals with familial hypercholesterolaemia (one homozygote, five heterozygote) and one normolipaemic individual. The first‐order disappearance constants (k) were derived for LDL and Lp(a) according to Apsteinet al.[1]. Thekvalues for LDL in the homozygous FH and the normolipaemic individual were 0.082 and 0.43 respectively while the heterozygous FH patients hadkvalues intermediate between the two (median 0.231; range 0.116–0.261). The first‐order disappearance constants of Lp(a) did not correlate with those of LDL. The homozygous FH and normolipaemic individuals had Lp(a)kvalues of 0.158 and 0.199 respectively; the corresponding values in the heterozygous FH patients were: median 0.142; range 0.

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Most epidemiologic studies of plasma lipoproteins and gonadal steroids have measured total hormone concentrations only. Gonadal steroids are transported in plasma in unbound, albumin‐bound and sex hormone‐binding globulin (SHBG)‐bound forms, only the first two of which are biologically active. In the present study the associations of plasma lipoproteins with the different fractions of testosterone, oestradiol and 5α‐dihydrotestosterone (5αDHT) were explored by multiple regression in 70 men aged 52–67 years (mean, 59 years). The principal finding was that the distribution of cholesterol between the two major subclasses of high density lipoprotein (HDL) was correlated with the concentrations of unbound and albumin‐bound oestradiol, but not with SHBG‐bound oestradiol or any fraction of testosterone or 5αDHT. These associations were independent of plasma triglyceride. Apoproteins A‐I and A‐II were not correlated with any hormone fraction. Thus, in middle‐aged/elderly men HDL subclasses appear to be influenced by circulating estrogenic activity, but not by androgenic activity, through a mechanism that is unrelated to triglyceride transport or HDL

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.We have examined resting and thrombin (0.3 units ml‐1) induced release of noradrenaline by washed platelets from 15 normal subjects and eight patients with heterozygous familial hypercholesterolaemia.Platelets from both normal and hypercholesterolaemic subjects showed irreversible aggregation with 0.3 units ml‐1thrombin. Extents of aggregation were 76.3% and 90.8% respectively, platelets from hypercholesterolaemic patients being significantly more sensitive (P<0.002).Under resting conditions platelet noradrenaline release was 136% greater (P<0.02) in hypercholesterolaemic patients than in normal subjects. Thrombin‐stimulated release of noradrenaline was also higher (73%,P<0.05) in hypercholesterolaemics than in normals. The differences between resting and thrombin‐stimulated release were greater for hypercholesterolaemic patients than normal subjects (P<0.05).Under resting conditions total platelet noradrenaline levels (sum of supernatant and platelet pellet concentrations) were similar in preparations from the two groups. However, following thrombin stimulation total noradrenaline concentrations were substantially greater (86%) in platelets from hypercholesterolaemics than normals (P<0.02). In hypercholesterolaemic patients thrombin stimulation was associated with an 101% increase (over resting levels) in total platelet noradrenaline (P<0.01), no increases being observed with normal subjects.We suggest that platelet membranes may be more permeable in patients with familial hypercholesterolaemia leading to increased non‐specific release of catecholamines. Platelets from patients with familial hypercholesterolaemia may also be more responsive to stimulation with respect to catecholamine release. The results obtained on calculation of total platelet noradrenaline levels may indicate that abnormalities of platelet dense granules occur in familial hypercholesterolaemia. In this context the relative proportions of free and conjugated catecholamine may be of relevance.The importance of lipoprotein‐platelet interactions has been emphasized as regards the development of atherosclerosis. Platelet thrombus formation is also of undoubted importance in myocardial infarction. The platelet abnormalities described in this paper may contribute to the increased risk of premature vascular disease in patients with familial hyperchole

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.The hypocholesterolaemic mechanism of activated charcoal was studied in seven patients with primary hypercholesterolaemia. The reduction of serum cholesterol was correlated with the serum concentrations of cholesterol precursors and of two plant sterols. Activated charcoal, 8 g t.i.d. for 4 weeks, reduced serum concentration of total cholesterol by 27% (P<0.01). The effect was accompanied by a moderate elevation (P<0.05) in serum squalene and desmosterol concentrations and by a marked increase (up to 300–700%) in serum lathosterol and Δ8latho‐sterol concentrations. The levels of two plant sterols, campesterol and β‐sitosterol, were unchanged or only slightly decreased by the use of activated charcoal. The decrease of serum cholesterol concentration had significant negative correlations with serum lathosterol and Δ8lathosterol, and significant positive correlations with serum cholestanol and β‐sitosterol. These observations suggest an increased cholesterol synthesis upon treatment with activated charcoal, probably caused by the interference with the enterohepatic circulation of

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00226.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Apolipoprotein B (apoB) is a major importance to the metabolism of lipoproteins, and there is also evidence which suggests that apoB plays a central role in atherogenesis. In order to study whether there is a link between one of the mutations of the apoB gene and premature coronary heart disease, the frequency of theXbaI RFLP for the apoB gene was analysed in 52 male myocardial infarction patients. These were compared with a control group matched for age and sex (n= 52), and a random population sample of middle‐aged men (n= 106).Two alleles were identified by the presence (X2) or the absence (X1) of anXbaI cleavage site.A somewhat higher frequency of the X2 allele was seen among the patients, however there was no significant difference between patients and controls regarding the genotypes or allele frequencies.This observation does not confirm one earlier report where a higher frequency of the X1 allele was seen in myocardial infarction patients. Differences between the studied populations or epidemiological designs of the studies might explain the diverging results. Further studies are evidently needed to fully resolve the relation between theXbaI RFLP and risk of atherosclerotic disease or lipoprotein metabolis

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00227.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Human chylomicrons, obtained from chylous pleural fluid of a patient with mesothelioma, were incubated with bovine milk lipoprotein lipase. No difference in the release of different C16–C18fatty acids as unesterified fatty acids, or in their appearance in diacylglycerols, was observed. The rate of lipolysis of arachidonic (20:4), and eicosapentaenoic (20:5) acid ester bonds of chylomicron triacylglycerols was slower, and a larger proportion of these fatty acids accumulated in mono‐ and diacylglycerols. The hydrolysis pattern for docosahexaenoic acid (22:6) was intermediary between that of the C16–C18fatty acids and that of 20:4 and 20:5. The data suggest that the presence of a double bond at position 5 in the eicosanoid precursors may be important for the rate of lipolysis. The relative resistance of the 20:4‐ and 20:5‐esters of chylomicrons to lipoprotein lipase may be important for the tissue distribution of these fa

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00228.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.We assessed the haemodynamic and renal effects as well as the effects on plasma cGMP levels of a small i.v. dose (33 μg) of human atrial natriuretic factor (99–126; hANF) in two age groups of healthy volunteers. Binding properties of platelet ANF receptors were also measured. The elderly (four males, eight females, mean age 52.3 years) showed increased haemodynamic (decrease in blood pressure) and renal responses (diuresis, natriuresis, calciuresis) as well as greater increases in plasma cGMP levels and urinary cGMP excretion than the young subjects (four males, 12 females, mean age 26 years). Binding capacities and affinities of platelet ANF receptors were identical in both groups.These data indicate that the sensitivity to ANF increases with age and that this increased sensitivity is reflected in the reactivity of plasma cGMP levels but not in the properties of platelet ANF receptors. The data may be important for the therapeutic use of ANF, for the understanding of the physiological regulation of ANF action and may underline the necessity of using age‐matched control subjects for clinical studies on the possible therapeutic effectiveness of

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00229.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.Atrial natriuretic peptide (ANP) increases renal sodium and water excretion in several species including man. In rats ANP was also found to influence water and electrolyte transport in the small intestine. In the present study we investigated whether ANP can alter transport in the jejunum and ileum of healthy volunteers using a triple‐lumen perfusion technique. The small intestine was perfused under steady‐state conditions with a plasma‐like electrolyte solution using polyethylene glycol as a nonabsorbable volume marker. After an initial control period with intravenous saline infusion ANP was administered intravenously at a dose of 400 pmol kg‐1h‐1. This dose led to a significant (P<0.05) increase in the plasma levels of ANP (up to 22‐fold) and cGMP (up to 15‐fold), and of urine volume. Intestinal water and electrolyte transport were, however, not affected by ANP. Our results suggest that circulating ANP does not play a role in the regulation of mucosal water and ion transport in the human sm

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00230.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.We studied aspirin‐induced injury to the gastric mucosa in control rats pretreated with a solubilizer, pluronic F‐68 (PL), and in rats pretreated with solubilized arachidonic acid (AA). Fasted male rats were pretreated intragastrically with 1 ml of either pluronic or AA and 1 h later acidified ASA (1 ml suspension of 200 mg kg‐1body weight) was administered intragastrically. Grossly apparent mucosal lesions developed 1 h after aspirin in pluronic‐pre‐treated rats, but were significantly reduced in AA‐pretreated rats. Histology, scanning and transmission electron microscopy demonstrated that AA pretreatment did not prevent aspirin‐induced initial damage to the surface epithelium but did significantly reduce extent of aspirin‐induced deep mucosal necrosis at 1,4 and 18 h after aspirin. Initial aspirin‐induced surface epithelial damage was rapidly restituted by two distinct types of re‐epithelialization ‐ vertical and horizontal. While the vertical type of re‐epithelialization has been reported previously as the first stage of mucosal repair following injury by various noxious agents such as concentrated ethanol, the horizontal type of re‐epithelialization, which is described for the first time in this paper, seems to be specific for the repair of aspirin‐induced gastric mucosal injury. These studies suggest that dietary factors such as essential fatty acids may play a role in gastric mucosal protec

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00231.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

Abstract.A new method was developed to measure gastrointestinal transit: a metal particle is followed on its way through the gastrointestinal tract by means of a portable metal detector. Deviation of measured localization of the metal particle from the exact site was 0.5–1.0 cm depending on its size and distance from the search probe. A metal sphere of 6 mm diameter can be located accurately in the body at a distance of 2–12 cm from the abdominal surface.Emptying of a metal particle from the stomach, its arrival at the caecal area and its passage through the colon into the rectum can be registered and hence, gastric residence time, small intestinal transit and transit through different parts of the colon were determined.Gastric residence time at the interdigestive phase was (mean ± SD) 67 ± 52 min in 20 persons with a range of 9–185 min. When gastric emptying was recorded by pH sensitive radiotelemetering capsule in 10 persons, correlation of both methods wasr= 0.99.Small intestinal transit averaged 110 ± 56 min in six healthy volunteers when breakfast was eaten after the marker had left the stomach. It was delayed to 218 ± 34 min (P<0.01) whan fasting was continued.Large intestinal transit of the metal marker was compared to whole body transit of radio‐opaque (‘Hinton’) markers. In nine normal persons, 70% of the Hinton markers were excreted together with the metal particle.It is concluded that this new method is suitable for studying a large variety of physiological, pathophysiological and pharmacological questions concerning gastrointestinal transit. It is inexpensive and easily performed, does not cause radiation exposure, and allows measurements under everyday

ISSN:0014-2972    

DOI:10.1111/j.1365-2362.1989.tb00232.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY