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Biomedical subjects

B Vessby

Publications and source records attributed to B Vessby.

At least 145 records · Page 8Linked to original sources
PubMed1985

Platelet fatty acid composition in relation to fatty acid composition in plasma and to serum lipoprotein lipids in healthy subjects with special reference to the linoleic acid pathway.

The fatty acid composition in platelet phospholipids and in the plasma lipid esters as well as the serum lipoprotein lipid concentrations were determined in 67 healthy male subjects in order to establish the relationships between blood lipids and platelets. A positive correlation was found between the concentrations of the triglyceride rich serum lipoprotein lipids and the relative percentage of saturated and monounsaturated fatty acids in plasma. The correlations were also positive between the serum high density lipoprotein-cholesterol concentration and the relative content of linoleic acid in the plasma cholesterol esters and phospholipids. Negative correlations were found between the relative percentage of saturated and monounsaturated fatty acids in the plasma lipid esters versus linoleic acid in plasma and in the platelets. On the other hand there were positive correlations between linoleic acid in the plasma lipid esters and in the platelet phospholipids. These results indicate a direct dietary influence on the platelet phospholipid fatty acid composition. The correlations between the fatty acids of the n-6 series within plasma and platelets as well as between plasma and platelets indicate that a high linoleic acid content is not associated with an increased arachidonic acid concentration. The results also indicate that the limiting metabolic step in the conversion of linoleic acid into arachidonic acid may be located at different levels in plasma and in the platelets.

Adult↗
PubMed1985

Effects on the serum lipoprotein concentrations by lipid-lowering diets with different fatty acid compositions.

It has been reported that lipid-lowering diets may reduce high density lipoprotein as well as low density lipoprotein cholesterol but that the reduction of the high density lipoproteins is less pronounced with diets of lower P/S ratios. The aim of the present study was therefore to investigate whether the effects on the low density lipoproteins could be maintained, but those on the high density lipoproteins diminished, by reducing the P/S ratio from 1.3 to 0.7. Fourteen hyperlipoproteinaemic patients in a metabolic ward were given two fat-modified diets during two consecutive 3-week periods in a randomized order. The diets were identical with regard to nutrient composition but differed with regard to the P/S ratios, which were 1.3 and 0.7, respectively. The average serum lipoprotein lipid composition and the apolipoprotein concentrations were similar at the end of the two periods. However, in the group of patients (n = 7) who started on the diet with P/S ratio 1.3 the low density lipoprotein cholesterol increased significantly (p less than 0.05) by 7% and the apolipoprotein B concentration by 10% (p less than 0.001) when shifting to the diet with P/S ratio 0.7. No changes of the high density lipoprotein concentrations were seen. The relative content of saturated fatty acids, of oleic acid, and of arachidonic acid in the plasma lipid esters decreased, but the content of linoleic acid increased, when shifting from the diet with a P/S ratio of 0.7 to that of 1.3.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1985

A sequential comparison of etretinate (Tigason) and isotretinoin (Roaccutane) with special regard to their effects on serum lipoproteins.

Etretinate and isotretinoin were compared with respect to their clinical effects and changes in serum lipoprotein concentrations. Sixteen patients with hyperkeratotic and pustular disorders of hands and feet (mainly palmoplantar pustulosis) underwent a double-blind cross-over study. The daily doses of etretinate and isotretinoin were 50 and 40 mg, respectively. Each drug was given for 2 months with a 2-month intermission. The clinical score was reduced both by isotretinoin (P less than 0.05) and etretinate (P less than 0.001). Both drugs affected the lipoprotein concentrations. Isotretinoin increased the cholesterol concentration in low-density lipoprotein (LDL) by 20% and the triglyceride concentration in very low-density lipoprotein (VLDL) by 35%, but decreased the high-density lipoprotein cholesterol by 12%. Etretinate elevated LDL-cholesterol by 10%. These changes had reverted to normal 8 weeks after the end of treatment. The data suggest that in the diseases studied, etretinate is preferable to isotretinoin with regard to both clinical effect and serum lipid side-effects.

Adult↗
PubMed1985

Diet therapy for poorly controlled type 2 (non-insulin-dependent) diabetes mellitus.

Poorly controlled type 2 diabetes represents a major therapeutic problem. A classification of the disease, based on body weight and presence or absence of adequate insulin-secretion capacity, may be helpful in the choice of correct treatment. Calorie reduction is the most important therapeutic intervention in overweight patients. In the diabetic diet digestible carbohydrates should comprise at least 50 energy%, while the fat content should be reduced below 30 energy%. Controlled clinical studies show that the blood glucose control can be improved and the urinary glucose excretion be diminished by addition of dietary fibre. In obese type 2 diabetics supplemented fasting may be useful to achieve a rapid weight loss and an improved metabolic control. Although our knowledge with regard to the patho-physiology of type 2 diabetes and the effects of dietary treatment has increased during recent years, several important questions remain unanswered. Also there is a great need for education and training programmes to achieve improved compliance to the dietary advice given.

Blood Glucose↗
PubMed1985

High muscle lipoprotein lipase activity in thyrotoxic patients.

Serum lipoprotein metabolism was studied in 7 women before and after treatment for thyrotoxicosis. Of the lipoprotein lipids, the triglyceride concentration in the low density lipoproteins (LDL) (P less than 0.01) and the cholesterol concentration in both LDL (P less than 0.01) and the high density lipoproteins (HDL) (P less than 0.05) increased significantly during treatment. These changes were accompanied by increases in apolipoprotein B (P less than 0.01) and A-I (P less than 0.05) concentrations in serum. Muscle lipoprotein lipase activity (LPLA) was increased in the thyrotoxic state by 46% (P less than 0.05) compared with the value after the patients had been rendered euthyroid, but adipose tissue LPLA was only 8% higher (ns) in the former state. The capacity for removal of exogenous fat, as determined by the fractional elimination rate (K2) at an iv fat tolerance test, was 23% higher in the thyrotoxic than in the euthyroid state (ns). It is suggested that the increase in muscle LPLA in the thyrotoxic state may be due to enhanced sensitivity to catecholamines. This may contribute to the increased capacity for plasma triglyceride turnover in thyrotoxicosis.

Adipose Tissue↗
PubMed1985

Changes in lipoprotein metabolism during a supplemented fast and an ensuing vegetarian diet period.

The effect on lipoprotein metabolism of a 2-week modified fast and an immediately ensuing 3-week period on a vegetarian diet was studied under metabolic ward conditions in 21 non-obese female and 6 male patients. The very low calorie diet induced reductions of the cholesterol concentration in all serum lipoprotein classes. In the female patients, who were all normolipoproteinaemic, the triglycerides in serum showed a slight increase during the fast, reflecting small changes in very low (VLDL) and low density lipoprotein triglycerides. This may probably be explained partly by simultaneous significant reductions of both the adipose tissue and skeletal muscle tissue lipoprotein lipase activities (LPLA). In contrast, in the male patients who had a higher VLDL level at admission, the VLDL triglycerides decreased without significant changes of high density lipoprotein (HDL) cholesterol and of LPLA in muscle. The female patients, whose weights were stable during the vegetarian diet, ended up with a lower HDL cholesterol than at the start of the trial. This effect was probably partly due to the high content of polyunsaturated fatty acids in the vegetarian diet. It is concluded that the changes of lipoprotein metabolism during supplemented fasting are quantitatively and qualitatively different in several respects in females and males.

Adult↗
PubMed1985

Is muscle lipoprotein lipase inactivated by ordinary amounts of dietary carbohydrates?

Lipoprotein metabolism was investigated in 12 patients, healthy except for renal stone disease, who received a high-protein experimental diet for 2 weeks under metabolic ward conditions. The results were compared with those after 2 weeks on a control diet of ordinary composition. The patients were randomly allocated to begin with the control or experimental diet. The energy contributions from protein, carbohydrate and fat were 12, 48 and 41 per cent in the control diet and 29, 31 and 41 per cent in the experimental diet, respectively. Fasting concentrations of very-low-density lipoprotein (VLDL) triglycerides and cholesterol were lower with the high-protein than with the control diet (0.69 vs 1.4 mmol/l, P less than 0.0001, and 0.33 vs 0.47 mmol/l P less than 0.01, respectively). High-density lipoprotein cholesterol tended to be higher (0.05 less than P less than 0.10) with the high-protein diet. Lipoprotein-lipase (LPL) activity in skeletal muscle and the fractional catabolic rate constant of an intravenous fat tolerance test were higher with the high-protein than with the control diet (38 vs 21 mU/l, P less than 0.01, and 5.1 vs 3.6 mU/l, P less than 0.001, respectively). Neither fasting blood glucose, intravenous glucose tolerance nor insulin concentrations differed between the two dietary periods. These findings indicate that an 'ordinary' intake of refined carbohydrates has an inhibitory effect on the muscle LPL activity, thereby increasing the VLDL level and slightly decreasing the level of high-density lipoproteins, which may be of relevance for the atherosclerotic process.

Adult↗
PubMed1984

Effects of an increased content of cereal fibre in the diet of Type 2 (non-insulin-dependent) diabetic patients.

The metabolic effects of an increased dietary content of cereal fibre were studied in 14 Type 2 diabetic subjects. They were given two isoenergetic diets in randomised order during two consecutive 3-week periods. A diabetic diet, containing 18.9 g dietary fibre/6.7 MJ (1600 kcal), was compared with a diet of identical composition except for an increased content of cereal fibre (42.4 g dietary fibre/6.7 MJ). The mean blood glucose level and the urinary glucose excretion were significantly lower in patients on the cereal-fibre-rich diet, while the serum insulin concentrations were similar. The mean blood glucose level was significantly reduced at 0700 h by 6% (p less than 0.05) and at 1100 h by 13% (p less than 0.01) on the high-fibre diet. Consequently the insulin/glucose ratio was higher (33%, p less than 0.02) in patients on the fibre-enriched diet. There were only minor differences with regard to the serum lipoprotein concentrations. The lipoprotein lipase activities were similar in the two dietary groups. The reduction of blood glucose concentrations together with unchanged serum insulin concentrations is compatible with improved peripheral insulin sensitivity.

Aged↗
PubMed1984

Increased high density lipoproteins in diabetic children.

Serum lipoprotein lipid and apolipoprotein concentrations were determined in 27 diabetic children (5-18 years old) and 13 matched healthy controls. The serum cholesterol concentrations in the diabetics were slightly higher than in the controls (P less than 0.05) due to a significantly higher level of the high density lipoprotein cholesterol (P less than 0.01). Also the serum concentration of apolipoprotein A-I, the major protein constituent of the high density lipoprotein fraction, was higher in the diabetic children (P = 0.05). There were no significant differences between the groups with regard to the serum triglyceride concentrations or the apolipoprotein C-II and C-III concentrations. Neither the lipoprotein lipid nor the apolipoprotein levels were significantly correlated with variables related to the degree of regulation of the diabetic disease. No obvious explanation, based on the present data, can be given for the increased high density lipoprotein cholesterol concentrations in insulin-treated diabetics in comparison with the healthy children. It is possible, however, that the increased high density lipoprotein cholesterol concentration may be caused by an increased level of insulin in the circulation of insulin-treated diabetic children.

Adolescent↗
PubMed1984

Further increase in high density lipoprotein in trained males after enhanced training.

Eight well-trained males were studied before, during and after 6 months of a progressively increased amount of endurance training in order to elucidate the effects on the apoproteins and apolipoproteins. Initially high HDL-cholesterol levels were revealed (1.62 +/- 0.15 mmol X 1(-1), mean +/- SE.). After a transient but not significant, slight decline at the onset of the increased training program (1.57 +/- 0.06 mmol X 1(-1] HDL-cholesterol increased gradually to the end of the training period (1.92 +/- 0.12 mmol X 1(-1). There was an increased aerobic capacity as judged by maximal oxygen uptake and by lactate concentration during standardized submaximal work. However, at the end of the training period, a levelling off in maximal oxygen uptake was revealed, while HDL-cholesterol was still increasing. The present data demonstrate that HDL can be influenced by training at all levels of aerobic capacity.

Adult↗
PubMed1984

Improved metabolic control after supplemented fasting in overweight type II diabetic patients.

Twenty obese type II diabetes patients were treated in a metabolic ward during 4 weeks with a very low calorie regimen (200 kcal/day). They were given dietary advice and reexamined 3 months after discharge. Mean body weight decreased by 10 kg during fasting, blood glucose was normalized, urinary glucose disappeared and the K-value at i.v. glucose tolerance test increased. Fasting serum insulin concentrations decreased by 54%. Serum triglycerides (TG) decreased by 65%, serum cholesterol (Chol) by 28% and high density lipoprotein (HDL) Chol by 14%. Three months later, only serum TG remained significantly decreased (-47%) while HDL Chol was significantly higher than on admission (+11%). Fasting blood glucose remained significantly lower (-25%) with a low urinary glucose excretion. Supplemented fasting appears to be a safe and useful tool in the treatment of obese type II diabetics. It causes, at least during a limited follow-up period, a significant improvement in glucose control and lipoprotein metabolism in spite of a concomitant reduction of the antidiabetic medication.

Adult↗
PubMed1984

Serum lipoprotein and apolipoprotein concentrations in patients with hyperthyroidism and the effect of treatment with carbimazole.

Forty patients, 32 women and 8 men, with hyperthyroidism were investigated concerning serum lipoprotein lipid and apolipoprotein concentrations before, during and after treatment with carbimazole to euthyroidism. During the hyperthyroid condition the patients had significantly lower serum concentrations of low density lipoprotein (LDL) and high density lipoprotein (HDL) cholesterol. The serum lipoprotein triglyceride concentrations were within the normal ranges. During treatment to euthyroidism the low serum concentrations of LDL and HDL cholesterol increased to normal values. LDL and HDL concentrations increased in the female patient group by 46 +/- 12 and 25 +/- 9% and in the male patient group by 50 +/- 12 and 19 +/- 11%, respectively. During treatment serum apolipoprotein B and A-I concentrations increased significantly in females by 58 +/- 9 and 18 +/- 5% and in males by 60 +/- 9 and 13 +/- 8%, respectively.

Adolescent↗
PubMed1984

Effects of high intake of dietary animal protein on mineral metabolism and urinary supersaturation of calcium oxalate in renal stone formers.

The metabolic effects of a high protein diet (HPD) were studied in eight patients with idiopathic recurrent calcium oxalate stones. On the HPD there was a 35% increase in urinary calcium concomitant with increased excretion of cyclic AMP and hydroxyproline. These findings point to an enhanced resorption of bone, possibly secondary to increased renal loss of calcium. The urinary citrate decreased by 25% along with reduced serum standard bicarbonate and urinary pH. The high formation of acid metabolites might also have adverse effects on calcium balance and bone. Urinary oxalate excretion was not affected nor were there any significant changes in the calculated urinary supersaturation of calcium oxalate, if changes in urinary citrate, pH, sulphate, sodium, phosphate and volume were also considered. This study suggests that the possible negative influence on the propensity to form renal stones of a diet rich in animal protein is probably due to reduced urinary inhibitory activity.

Adult↗
PubMed1984

Lipoproteins, lipoprotein lipase, and glycogen after prolonged physical activity.

The effect of strenuous exercise on lipoprotein level and composition as well as on lipoprotein lipase activity (LPLA) and glycogen stores in skeletal muscle was studied in 16 healthy young men after military field maneuvers. Body weight was reduced by 1 kg after the maneuvers and was gradually restored during a 5-day recovery phase. Glycogen levels were reduced by 50% and LPLA increased threefold immediately after the exercise, and neither were restored until 3-5 days of recovery. Serum triglycerides were decreased by about 50% after 1 day of recovery and the cholesterol concentration in high-density lipoproteins increased but only immediately after exercise. In contrast, the apolipoproteins A-I and A-II, the main protein constituents, were both decreased and remained so for 3-5 days. The results indicate that significant alterations of plasma lipoprotein level and composition as well as of muscle metabolism occur after prolonged physical exertion and that some changes are still evident after 5 days of recovery.

Adult↗
PubMed1984

A rapid radioimmunoassay of human apolipoproteins C-II and C-III.

Apolipoprotein (apo) C-II is an activator of lipoprotein lipase, while apo C-III has the ability to inhibit apo C-II activated lipolysis. In order to study further the relationship between lipoprotein lipase mediated hydrolysis and the serum concentrations of apo C-II and apo C-III we have developed radioimmunoassays for these apolipoproteins. Apo C-II and apo C-III were isolated from very low density lipoproteins (VLDL) by ion exchange chromatography. Apo C-II was further purified by affinity-chromatography. The purity of the two proteins was determined to be greater than 98% by polyacrylamide gel electrophoresis and immunodiffusion. The purified apolipoproteins were used as antigens, assay standards and labels. Formalin-treated Staphylococcus aureus Cowan I was used for immunoprecipitation and were shown to give rapid uptake of immune complexes that could easily be harvested by centrifugation. The assays were shown to be sensitive (10 micrograms/l), specific, precise (inter- and intra-assay coefficients of variation below 10%), rapid (completed in less than 6 h) and simple to perform. Delipidation of serum and lipoproteins had no effect on the results, indicating that the immunologically active sites of apo C-II and apo C-III are exposed to the aqueous environment under assay conditions. Serum apo C-II and apo C-III levels of normolipidaemic subjects were approximately 25 mg/l and 110 mg/l, respectively. Highly significant positive correlations were found between VLDL apo C-II and VLDL apo C-III, respectively, and VLDL triglycerides, VLDL cholesterol and total serum TG. There was also a highly significant correlation between the HDL cholesterol concentration and the HDL apo C-III concentration.

Apolipoprotein C-II↗
PubMed1984

Unaltered lipoprotein and carbohydrate metabolism during treatment with contraceptive subdermal implants containing ST-1435.

Nine healthy, fertile women were treated for six months with subdermal contraceptive implants of two different sizes containing a potent progestogen, ST-1435. Lipoprotein cholesterol and triglyceride concentrations were not influenced by the treatment. Similarly, the main apolipoproteins in low- and high-density lipoproteins were not changed, which further supports the interpretation that the lipoprotein metabolism is not affected by this type of treatment. An oral glucose tolerance test (OGTT) including insulin determinations was performed in five of the volunteers with the largest implants. Blood glucose and insulin concentrations during the OGTT remained unchanged during treatment, indicating that the treatment with ST-1435 did not affect carbohydrate metabolism.

Adult↗