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Biomedical subjects

L A Carlson

Publications and source records attributed to L A Carlson.

At least 109 records · Page 6Linked to original sources
PubMed1980

Central and peripheral circulatory effects and metabolic effects of different prostaglandins given I.V. to man.

Cardiac output, heart rate, stroke volume, pressures in the brachial artery, right ventricle and pulmonary artery, forearm blood flow, and arterial concentration of FFA, lactate and glucose were measured in healthy male volunteers during i-v infusion of PGE1, PGE2, PGF2 alpha or 15-methyl PGF2 alpha in increasing doses. In accordance with previous findings PGE1 and PGE2 increased cardiac output by a vasodilating effect in the systemic and pulmonary vascular bed, probably in combination with an inotropic effect on the heart. 15-methyl PGF2 alpha had essentially the same cardiovascular effects as PGF2 alpha. They induced a slight increase in cardiac output due to effects on heart rate, while systemic vascular resistance was unchanged. Forearm vascular resistance increased and pressures in the pulmonary circulation rose, indicating a vasoconstriction in these vascular beds. Glucose concentrations was not affected nor were lactate concentrations, except for a slight decrease of unclear significance in the group receiving 15-methyl PGF2 alpha. FFA increased slowly in the same manner as seen spontaneously in fasting individuals. These data do not indicate direct metabolic effects of the prostaglandins studied when given i-v.

Adult↗
PubMed1980

Increased frequency of late pre- beta lipoproteins (LP beta) in isolated serum very low density lipoproteins in uraemia.

Hypertriglyceridaemia, which is caused by raised levels of the triglyceride rich serum very low density lipoproteins (VLDL), is common in uraemia. Here we report qualitative studies on VLDL in this condition. VLDL were isolated from serum of 137 uraemic patients by ultracentrifugation, subjected to agarose electrophoresis and stained for lipids. An increased frequency of presence of electrophoretically slow migrating, discrete VLDL band, the so-called late pre- beta lipoproteins, LP beta, was found, 76% in uraemia versus 30% in controls. Patients on haemodialysis had a higher frequency of LP beta than those not on dialysis, 94% versus 69%. Furthermore the cholesterol/triglyceride ratio of VLDL was raised by about 30% in uraemia. Since the cholesterol enriched LP beta is believed to represent an end stage of the catabolism of VLDL these data suggest that there is a delayed clearance of VLDL remnants in uraemia. In haemodialysis patients heparin might have contributed to the higher frequency of LP beta.

Cholesterol↗
PubMed1980

Studies on the fat emulsion Intralipid. I. Association of serum proteins to Intralipid triglyceride particles (ITP).

Intralipid triglyceride particles (ITP) were isolated by density gradient centrifugation. The isolated ITP fraction contained about 70% of the total triglycerides and 20% of the total phospholipids of the original Intralipid emulsion. Intralipid emulsion was mixed with equal parts of either albumin solution or VLDL-free serum and the ITP immediately isolated by centrifugation. The isolated ITP contained protein of which more than 90% disappeared upon recentrifugation in the case of albumin and only to 20% in the case of serum. It was demonstrated by polyacrylamide disc gel electrophoresis and double immunodiffusion with monovalent antisera against apolipoproteins that the proteins associated with ITP were mainly albumin; apolipoproteins CII and CIII in the two types of experiments respectively. The specific association of apolipoproteins CII and CIII to ITP offers an explanation to the chylomicron like metabolism of Intralipid in vivo.

Apolipoproteins↗
PubMed1980

Studies on the protein composition of human serum very low density lipoproteins with particular reference to the presence or absence of late pre-beta lipoprotein (Lp beta).

The amount of tetramethylurea and isopropanol soluble protein, total protein, triglycerides and cholesterol was determined in very low density lipoprotein (VLDL) showing either pre-beta mobility, or combined pre-beta and late pre-beta (Lp beta) or beta-mobility from twenty-two different sera. The ratios cholesterol to triglyceride of the VLDL preparations varied between 0.30 and 1.75. A very strong positive linear correlation between soluble protein and triglycerides over the whole range of VLDL preparations was obtained. There was no difference between sera with and without Lp beta for this relationship. When apolipoprotein B, was plotted against triglycerides, a weak correlation was obtained, and VLDL preparations without Lp beta separated into a group below the regression line, indicating that Lp beta is triglyceride poor in relation to apolipoprotein B. The corresponding plot against cholesterol gave a better correlation but with an even distribution of values of VLDL with and without Lp beta. Total and soluble protein put against cholesterol showed a pronounced tendency of VLDL with pure pre-beta mobility and those with Lp beta mobility to separate into groups, demonstrating that Lp beta is cholesterol rich relative to protein. The findings indicate that Lp beta-containing VLDL may represent the presence of a partly degraded VLDL.

Apolipoproteins↗
PubMed1979

Fish-eye disease. A new familial condition with massive corneal opacities and dyslipoproteinaemia.

A man and his three daughters had massive corneal opacities called in their home village "fish-eye disease" because of the resemblance of the eyes to those of boiled fish. The two living daughters had the same dyslipoproteinaemia, characterised by normal serum cholesterol but raised serum triglycerides, raised very-low-density lipoproteins, strikingly high levels of low-density lipoprotein (LDL) triglycerides. LDL contained normal sized as well as abnormally large particles and a 90% reduction in the level of high-density lipoprotein (HDL) cholesterol. Lecithin:cholesterol acyltransferase (LCAT) activity and the percentage of plasma cholesterol esters were normal, with excluded LCAT-deficiency. Normal electrophoretic mobility of HDL as well as other lipoprotein findings excluded Tangier disease. The clinical and laboratory abnormalities in fish-eye disease are atherosclerosis at old age, visual impairment, and dense corneal opacification. Fish-eye disease thus differs both clinically and in its lipoprotein abnormalities from LCAT-deficiency and Tangier disease.

Adolescent↗
PubMed1979

Occurrence of acute myocardial infarction in Stockholm studied by two different methods.

Two studies on the occurrence of acute myocardial infarction (AMI) in Stockholm have been made. In one, the study population consisted of patients who attended a health-control station; cases of AMI were detected retrospectively by a mail questionnaire and by the official cause-of-death register. In the other study, the population comprised the total population of Stockholm county; cases of AMI were detected from routine information on hospital care, and from the official cause-of-death register. The aims of the present study were to compare the two methods for detection of AMI cases and to compare the AMI morbidity of the two populations. The mail questionnaire method missed a small number of cases but, on the other hand, the register method included some cases in which the diagnostic criteria were not fulfilled. The AMI morbidity in the two populations did not differ significantly.

Acute Disease↗
PubMed1979

Effect of plasma free fatty acid lowering on exercise tolerance and ST segment depression in patients with angina pectoris.

The effect of a single oral dose of a plasma FFA-lowering drug (5-(3-pyridyl) tetrazole), which does not act by conversion into nicotinic acid, on exercise tolerance and ECG reaction was studied on a double-blind basis in 15 men with stable angina pectoris. Exercise was performed on a bicycle ergometer in the sitting position with a load increase of 10 W/min. In addition to ECG, time to onset of chest pains and to termination of exercise because of strong chest pains was recorded. 5-(3-pyridyl) tetrazole decreased plasma FFA during exercise from 523 to 299 mumol/l. It reduced significantly the ST depression at corresponding work loads and permitted the patients to exercise 0.6 min longer, corresponding to a 7% higher work load, before the onset of chest pain. However, absolute exercise time was not significantly increased. The most probable explanation of the improved performance is a decreased lipid and increased carbohydrate oxidation by the ischemic heart, although a contribution may have come from hemodynamic effects of the drug, unrelated to effects on myocardial metabolism but perhaps involving heart rate and BP. The lack of a significant effect on performance time may have been due to general fatigue.

Administration, Oral↗
PubMed1979

Insulin and substrate exchange in the forearm during prolonged forearm work.

Forearm exchange of insulin and uptake of oxygen, glucose and free fatty acids (FFA) were studied during 120 min forearm work in six healthy male volunteers. At rest the arterial-deep venous difference of insulin was zero. At the onset of work release of insulin occurred, which continued at constant rate throughout the work despite unaltered arterial insulin concentration. Extractions of oxygen, glucose and FFA were of similar magnitudes at 120 as at 15 min work, while lactate release decreased with time. It is concluded that (1) a significant insulin release from muscle tissue or its vascular bed occurs and continues at undiminished rate during prolonged work, (2) a substantial amount must be bound in the tissue, unless local synthesis takes place and (3) despite this loss of insulin from the forearm no major change in glucose and FFA extraction occurs with duration of work.

Adult↗
PubMed1979

Changes in plasma very low density and low density lipoprotein content, composition, and size after a fatty meal in normo- and hypertriglyceridemic man.

Four subfractions of plasma VLDL characterized by decreasing Sf value and LDL were isolated by density gradient preparative ultracentrifugation from normotriglyceridemic (NTG) and hypertriglyceridemic (HTG) (type IV) subjects in the fasting state and after a fatty meal. Chemical analysis and computation of numbers of particles in each fraction showed that the hyperlipidemia of type IV subjects was accounted for by an increase in total numbers of VLDL and a shift in the distribution of VLDL towards particles of larger diameter. Postprandial hyperlipidemia was due to the presence of chylomicron remnants rather than intact chylomicrons, and was accounted for by an increase in particle diameter of the largest VLDL subfraction rather than by an increase in particle numbers. Postprandial hyperlipedemia was accompanied by a shift in the distribution of VLDL towards particles of larger diameter in both NTG and HTG subjects, probably because of competition for the triglyceride-depletion process between chylomicrons and hepatic VLDL. Most chylomicron remnants were removed from the circulation without degradation to smaller VLDL or to LDL, but some remnants were sufficienty small to contribute to smaller VLDL subfractions. The LDL of type IV subjects contained more apoprotein B than those from NTG subjects, and this difference was associated with increases in diameter, molecular weight, density, and the ratio of protein: phospholipid in LDL from type IV subjects. Defective degradation of large VLDL to small VLDL, and of VLDL to LDL may be related to this alteration in apoprotein B content of the lipoproteins in type IV subjects.

Apolipoproteins↗