Biomedical subjects

B Vessby

Publications and source records attributed to B Vessby.

At least 163 records · Page 9Linked to original sources

PubMed1984

Pharmacodynamics of a contraceptive vaginal ring releasing norethindrone and estradiol: ovarian function, bleeding control and lipoprotein patterns.

A new contraceptive vaginal ring (CVR), releasing approximately 700 micrograms of norethindrone (NET) and approximately 140 micrograms of estradiol (E2) daily, was studied in eleven women for a total of 61 21-day cycles. Ovarian function, as judged by plasma progesterone (P) and E2 levels, and plasma NET levels were studied by weekly blood samples in 30 cycles. The lipoprotein pattern was studied before, after two and six months of treatment and one month after completed treatment. The CVR gave rise to stable plasma NET levels which however varied considerably between individuals. Signs of luteal activity/ovulation were encountered in 4/30 cycles, all in subjects with the lowest NET plasma levels. E2 levels above 250 pmol/l, indicating follicular activity, were encountered in 22/30 cycles. Breakthrough bleeding and spotting appeared in 40/61 cycles and in 12 per cent of the treatment days. Bleeding control was significantly better in the same subjects when using a CVR releasing levo-Norgestrel and E2. Serum and HDL cholesterol concentrations decreased significantly by 10-12 per cent during treatment. The ratios between apolipoproteins A-I and A-II on one hand and HDL cholesterol on the other increased significantly and the ratio apolipoprotein A-I:A-II decreased significantly, indicating a change in the lipoprotein composition. These changes are qualitatively similar but quantitatively not as pronounced as with the more extensively studied 1-Ng/E2 CVR. The difference in clinical performance and in the effects on the lipoprotein pattern between the presently studied CVR and the 1-Ng/E2 CVR is most likely the result of not using equipment doses of gestagen in the CVRs.

Adult↗

PubMed1984

Lack of effect of a purified bran preparation in men with low HDL cholesterol.

In 21 men who had been on a lipid-lowering diet for several years, the serum triglyceride and cholesterol levels had become normal on that treatment. In spite of this they all had low levels of cholesterol in the high density lipoproteins (HDL). In an effort to normalize this they were given a purified concentrated bran product (FiberformR, 3.5 g) three times daily for 6 weeks. The cross-over study was double-blind, placebo-controlled, and with a wash-out period between the treatment periods. There were no statistically significant changes in body weight, serum triglycerides and cholesterol or HDL triglycerides and cholesterol in association with the bran treatment. It is concluded that wheat bran in moderately large doses that are convenient to take does not offer a therapeutic alternative for increasing subnormal HDL cholesterol levels in normocholesterolaemic men.

Cholesterol↗

PubMed1983

Increased platelet aggregability in diabetic children: relation to serum lipid and fatty acid composition.

Platelet aggregation was studied in 14 diabetic children with no signs of angiopathy and in 14 healthy matched control children. The magnitude of the platelet shape change after ADP stimulation was decreased in diabetic patients while the maximal aggregation after ADP and low dose collagen was significantly higher than in healthy control children. In 28 diabetic children the platelet shape change after ADP stimulation was positively correlated with the serum concentration of apolipoprotein A-I and negatively correlated with serum triglyceride concentration. The ratio between the fatty acids 20:3/20:4 in cholesterol esters was strongly correlated with the relative incidence of irreversible aggregation (p less than 0.001) and with the magnitude of the maximal aggregation (p less than 0.01) after ADP stimulation (3.3 mumol/l). The ratio between the polyunsaturated and saturated fatty acids in the triglyceride fraction was negatively correlated to the maximal aggregation after collagen stimulation (10 mg/l). This study shows tha platelet aggregation is increased early in the course of diabetes in childhood. It suggests that the abnormalities in platelet aggregation pattern in diabetic patients are related to several of the lipid factors associated with an increased risk of atherosclerosis.

Adenosine Diphosphate↗

PubMed1983

Ovarian function, bleeding control and serum lipoproteins in women using contraceptive vaginal rings releasing five different progestins.

Ovarian function, bleeding patterns and serum lipoproteins were studied in women using contraceptive vaginal rings (CVRs) of dimethyl-polysiloxane impregnated with steroids. The different CVRs were used for about 10 cycles each. The following groups were studied, with the daily steroid dosage given in parentheses. Women using CVRs delivering levonorgestrel (290 micrograms), norethisterone (850 micrograms), medroxyprogesterone acetate (700 micrograms) or megestrol acetate (1.9 mg), all of which were in combination with estradiol (200 ug). Women using CVRs delivering progesterone (5.2 mg). Women taking megestrol acetate orally (15 mg/day) for three weeks. In all women except those using the levonorgestrel CVR, there were indications of incomplete suppression of ovarian activity as shown by elevated levels of progesterone and/or estradiol peaks. Bleeding control seemed to be good with the levonorgestrel CVR and rather poor with the others. Levonorgestrel treatment was associated with a decrease in high density lipoprotein cholesterol (32%) and triglycerides (25%) and a 16% decrease in apolipoprotein A-I. Norethisterone induced a 10% decrease in A-I and a reduction of cholesterol in very low density lipoprotein. All other lipid and apolipoprotein B, A-I and A-II values were unaltered with the administration of the CVRs and with oral megestrol acetate. Levonorgestrel was given in a higher dose than the other progestins, but the absence of effects of the high oral dose of megestrol acetate on the serum lipoproteins indicates that the progesterone-derived progestins in adequate doses probably would not alter the lipoprotein metabolism. Higher doses of progestins are needed to achieve acceptable control of ovarian activity and bleeding patterns than seen with these CVRs.

Cholesterol↗

PubMed1983

Cholesterol content as a possible determinant in the removal of chylomicron triglyceride by the liver.

The nature of chylomicron removal from the circulation and the role of the liver in this process have been investigated by measuring the removal of chylomicron triglyceride and cholesterol from the plasma of normal and functionally hepatectomized rats. The rate of removal of chylomicron triglyceride exceeded that of both free and esterified cholesterol in all animals. Whereas chylomicrons were completely removed from the circulation of normal rats soon after intravenous injection, chylomicron remnant particles accumulated in the plasma very low density lipoprotein and chylomicron fractions of hepatectomized rats. The rate of removal of chylomicron triglyceride from the blood of the hepatectomized rats decreased when the cholesterol content of the chylomicrons was elevated. In addition, more chylomicron triglyceride remained in the circulation of the hepatectomized rats when the chylomicrons were enriched with cholesterol and the remnant particles derived from these chylomicrons were of lower average density. These observations indicate that the cholesteryl ester content of the chylomicrons influences the degree of triglyceride removal in extrahepatic tissue capillaries and thereby the amount of residual triglyceride in the remnant particles subsequently removed by the liver.

Animals↗

PubMed1983

The influence of a high dietary intake of purine-rich animal protein on urinary urate excretion and supersaturation in renal stone disease.

1. Eight recurrent renal stone-forming patients were housed in a metabolic ward and fed on a low (LPD) and a high (HPD) animal protein diet, which were isoenergetic. Metabolic studies were made after 2 weeks on each diet. 2. There was a 90% increase in urinary urate on HPD compared with LPD, whereas serum urate did not change consistently. 3. The urinary acid excretion increased by 200%, including a 100% increase in ammonium ion excretion. A fall in urine pH by 0.9 unit was also seen. 4. The calculated ion activities of the urines revealed a profound increase in the uric acid supersaturation, from undersaturation to supersaturation, and in some cases even surpassing the formation product ratio. The ammonium urate supersaturation also increased. The sodium urate supersaturation was unchanged, despite an induced natriuresis. 5. The risk of forming uric acid or ammonium urate crystals or stones in the urine was increased on a high protein diet, whereas the risk of forming sodium urate crystals was no greater than on a low protein diet. 6. As uric acid and ammonium urate crystals under certain conditions may adsorb a macromolecular fraction of the human urine, which inhibits calcium oxalate crystal growth, it is proposed that this mechanism, along with a decrease in urine pH, may also interfere with the inhibitory activity of calcium oxalate crystal growth and aggregation.

Adult↗

PubMed1983

Similar serum lipoprotein reductions by lipid-lowering diets with different polyunsaturated:saturated fat values.

Lipid-lowering diets enriched in polyunsaturated fat decrease the serum cholesterol in hyperlipoproteinaemia, usually by reducing both the low-density-lipoprotein (LDL) and high-density-lipoprotein (HDL) cholesterol concentrations. The aim of the present study was to investigate whether the effects on LDL could be maintained but those on HDL cholesterol be diminished by reducing the ratio, polyunsaturated:saturated fat (P:S) of the diet. Twenty hyperlipoproteinaemic patients (six with type IIa, eight with type IIb and six with type IV) 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 values, which were 2.0 and 1.3 respectively. The lipoprotein-lipid composition and serum apolipoprotein concentrations were similar at the end of the two dietary periods in type IIa and type IV patients but in type IIb patients a more pronounced reduction of the LDL-cholesterol concentration by 9% (P less than 0.05) was achieved on the diet with the higher P:S value. The HDL-cholesterol did not differ significantly. The results indicate that increasing the P:S value of lipid-lowering diets from 1.3 to 2.0 does not offer a great advantage with regard to the lipoprotein-lipid reductions achieved in moderate hyperlipoproteinaemia.

Adult↗

PubMed1983

Effects of continuous levonorgestrel treatment (subcutaneous capsules) on the lipoprotein and carbohydrate metabolism in fertile women.

The lipoprotein and carbohydrate metabolism was studied during contraceptive treatment with levonorgestrel, released at a low rate (70 micrograms/day) from subcutaneous capsules, in five women who were treated for 180-403 days. The serum cholesterol concentration decreased slightly but significantly during treatment. This was attributable to a tendency to a reduction of cholesterol in high-density lipoproteins. The treatment did not affect the lipoprotein lipase activity in adipose tissue. The elimination rates of intravenously injected fat and glucose were unchanged, as were the serum insulin concentrations. Thus, in this pilot study the concentration and composition of the serum lipoproteins altered to only a minor extent during treatment with levonorgestrel in a dose of 70 micrograms/day.

Adult↗

PubMed1983

Changes in metabolism during a fasting period and a subsequent vegetarian diet with particular reference to glucose metabolism.

During an investigation on the effect of fasting and a vegetarian diet on the symptoms and signs in chronic cutaneous and arthritic diseases studies were made of glucose metabolism, liver function and the plasma concentration and urine excretion of some minerals. The study was performed on 27 patients who stayed as in-patients on a metabolic ward for five weeks. After the fasting period the blood glucose and serum insulin concentrations were lower (p less than 0.01) than before the fast. At the end of the period on the vegetarian (vegan) diet (three weeks) the insulin/glucose ratio was lower than at the start of the fast. Serum enzyme concentrations reflecting liver function increased during the fast, but normalized during the vegan diet. The intake of vitamin B12 and of selenium due to the vegan diets was very low, which may give reason for some concern during long-term use of this type of vegetarian diet.

Adult↗

PubMed1983

A fasting and vegetarian diet treatment trial on chronic inflammatory disorders.

Twenty patients with arthritis and various skin diseases were studied on a metabolic ward during a 2-week period of modified fast followed by a 3-week period of vegetarian diet. During fasting, arthralgia was less intense in many subjects. In some types of skin diseases (pustulosis palmaris et plantaris and atopic eczema) an improvement could be demonstrated during the fast. During the vegan diet, both signs and symptoms returned in most patients, with the exception of some patients with psoriasis who experienced an improvement. The concentrations of lactoferrin in serum reflect the turnover and activity of neutrophil leukocytes. When this protein was initially increased it fell to normal values in most cases. The improvement or impairment of signs and symptoms was related to the lactoferrin levels in serum.

Adult↗

PubMed1983

Dietary animal protein and urinary supersaturation in renal stone disease.

Eight stone-forming patients were given diets that were high (HPD) and low (LPD) in dietary animal protein, each for two weeks. Urines were collected by the end of each diet period. Urinary calcium, phosphate, urate and acids were increased on HPD whereas citrate and urine-pH decreased. The urinary supersaturation and thereby the risk of forming crystals and stones of uric acid and ammonium urate was increased on HPD. The supersaturation of calcium oxalate was unchanged, but the inhibition of calcium oxalate crystallisation may have become unfavourably affected.

Calcium↗

PubMed1982

Changes in glucose tolerance and plasma insulin during lipid-lowering treatment with diet, clofibrate and niceritrol.

In an effort to reduce serum lipids in patients with atherosclerotic manifestations, a combined treatment with a conventional lipid-lowering diet, clofibrate and niceritrol was used. The effect on glucose metabolism of such treatment was studied. Among the 106 patients 66 took the full dose of both drugs and of these 51 were weight-stable and non-diabetic. The effects of the diet and the drugs were evaluated in this subsample. Diet had no effect on fasting blood glucose concentration, the K value of an intravenous glucose tolerance test (IVGTT) and concentrations of serum insulin. Niceritrol treatment was associated with increased blood glucose, decreased K value, elevated fasting serum insulin and serum insulin at 60 min during IVGTT. Clofibrate had the opposite effects to niceritrol and when both drugs were combined, carbohydrate metabolism was unchanged compared with the pre-treatment state.

Aged↗

PubMed1982

Diverging effects of cholestyramine on apolipoprotein B and lipoprotein Lp(a). A dose-response study of the effects of cholestyramine in hypercholesterolaemia.

Nineteen hypercholesterolaemic patients were randomly treated with either 16 or 8 g cholestyramine with a changeover after 6 weeks for a second 6-week period. During a third consecutive 6-week period all patients received 4 g cholestyramine daily. The low density lipoprotein (LDL) cholesterol and triglyceride concentrations decreased significantly (- 11%, - 21% and - 26% for LDL cholesterol on 4, 8 and 16 g, respectively) with a dose-response effect. However, the increase from 8 g to 16 g only caused a modest additional reduction of the lipid levels. The serum concentration of apolipoprotein (apo) B was correlated to the LDL cholesterol and decreased similarly in a dose-response fashion. However, the average reduction of apo B was less pronounced (- 4%, - 13% and - 17% on 4, 8 and 16 g of cholestyramine, respectively) resulting in a significant change of the apo B/LDL cholesterol ratio during treatment. There was a significant increase of the high density lipoprotein (HDL) cholesterol concentration, which was similar at all dose levels. Also, the apo A-I concentration in serum increased significantly but the relative decrease was less pronounced than that of HDL cholesterol, causing a significant decrease of the apo A-I/HDL cholesterol ratio. The apo A-II concentration in serum was unchanged or slightly decreased and the apo A-I/apo A-II ratio increased significantly.

Adolescent↗

PubMed1982

Elevated lipoprotein lipase activity in skeletal muscle tissue during treatment of hypertriglyceridaemic patients with bezafibrate.

Eleven hypertriglyceridaemic patients were treated with 600 mg bezafibrate daily for 2 months. The mean serum triglyceride concentration decreased by 35% (P less than 0.01) corresponding to a reduction in the very low density lipoprotein triglycerides by 41% (P less than 0.01). The high density lipoprotein cholesterol concentration and the serum concentration of apolipoproteins AI and AII increased by 19% (P less than 0.02), 11% (N.S., P less than 0.08) and 24% (P less than 0.01), respectively. The fractional removal rate (K2) in the intravenous fat tolerance test (IVFTT) increased by 37% (P less than 0.001). This was associated with significant increase of the skeletal muscle lipoprotein lipase activity ( + 39%, P less than 0.05). The mean value for the adipose tissue lipoprotein lipase activity remained unchanged. The K2 at IVFTT was correlated highly significantly to the activity of skeletal muscle lipoprotein lipase (r = 0.85, P less than 0.01). The present study indicates that the main reason for the reduction of the serum triglycerides during treatment with bezafibrate may be an increased activity of the skeletal muscle tissue lipoprotein lipase activity.

Adipose Tissue↗

PubMed1982

Decrease of lipoprotein lipase activity in skeletal muscle in man during a short-term carbohydrate-rich dietary regime. With special reference to HDL-cholesterol, apolipoprotein and insulin concentrations.

Seven men took part in a study in which the diet was changed from an ordinary mixed one to a fat-rich diet [greater than 70% energy (E)] for 3 days followed by a carbohydrate-rich diet (greater than 70% E) for 3 days. Blood was drawn and muscle biopsies [for analysis of lipoprotein-lipase (LPL) activity] were taken before the study and at the end of each diet period. Insulin, apolipoprotein (apo) B, A-I and A-II, cholesterol and triglyceride concentrations were determined in serum and the lipids also in the high density lipoproteins (HDL). Serum insulin was higher (p less than 0.01) during the carbohydrate-rich diet than during the fat-rich diet (12.0 +/- 0.9 vs. 7.5 +/- 0.5 microunits/l, mean +/- SEM), as were serum-triglycerides (2.42 +/- 0.27 vs. 0.98 +/- 0.07 mmole/1, p less than 0.001). Muscle LPL activity, on the other hand, was lower (p less than 0.01), 27.3 +/- 6.1 vs. 75.1 +/- 13.2 microunits/g. HDL-cholesterol was 1.22 +/- 0.08 during the carbohydrate-rich diet which was lower (p less than 0.01) than during the fat-rich diet, 1.45 +/- 0.11. The concentration of apo A-I and A-II did not vary significantly. It is suggested that the increased insulin concentrations during a short-term, carbohydrate-rich diet may have a down-regulating effect on muscle LPL activity. Low muscle LPL activity may account for part of the elevation of serum triglycerides. An ineffective hydrolysis of VLDL-triglycerides may contribute to the variation in HDL-cholesterol concentration seen under these circumstances.

Adolescent↗

PubMed1982

Serum apolipoproteins A-I, A-II and B in diabetic children and matched healthy controls.

Serum concentrations of apolipoprotein (apo) A-I. A-II and B were determined in 28 diabetic children (age 3-16 years) and 14 healthy matched controls. In the healthy children the serum apo A-I concentration was 120 +/- 20 arbitrary units (A.U.) (mean +/- S.D.), apo A-II 111 +/- 14 A.U. and apo B 100 +/- 34 A.U. (100 A.U. = mean concentration in adult blood donors). The apo A-I concentration was significantly higher in the diabetic children (134 +/- 13; p less than 0.02) than in the healthy controls. In diabetics apo A-II was 116 +/- 14 A.U. and apo B 106 +/- 21 A.U., values not significantly different from those in the controls. The serum cholesterol concentration in the healthy children correlated strongly to apo A-I and apo A-II, which was not the case in the diabetics. The differences between diabetic and healthy children with respect to correlations between the apolipoproteins and the serum lipids might indicate a different apolipoprotein/lipoprotein lipid relationship in diabetics.

Adolescent↗

PubMed1982

Serum lipoprotein and apolipoprotein changes during treatment with a contraceptive vaginal ring containing levonorgestrel and estradiol.

Contraceptive vaginal rings containing estradiol and levonorgestrel were used by 22 women during 219 cycles. The estrogenicity was low and the daily dose of levonorgestrel was about 290 micrograms. The triglyceride and cholesterol concentrations decreased in whole serum and, to varying degrees, in the different lipoprotein classes. The most consistent change was a 25% (p less than 0.001) reduction in the cholesterol content of the high-density lipoprotein (HDL) fraction. The cholesterol concentration in low-density lipoprotein decreased by 11% after the first 3 months, but increased during the ensuing 9 months of treatment to regain pretreatment level. Percentage-wise, the apolipoprotein B and A-I concentrations, determined by rocket immunoelectrophoresis, were less affected than the LDL- and HDL-cholesterol concentrations. The composition of the LDL and HDL particles seemed thus to alter during the treatment. The pronounced effect on the HDL levels seen is consistent with earlier findings of a dose-dependent, androgenic effect of gestagens derived from 19-nortestosterone. However, the low basal level of LDL and its further decrement during treatment alleviate the supposedly unfavorable effect of HDL reduction from the atherogenic point of view.

Adult↗

PubMed1982

Fatty acid composition of serum lipids in diabetic children and their matched healthy controls.

The fatty acid compositions of the serum cholesterol esters, phospholipids and triglycerides were determined in 28 insulin-dependent diabetic children and 13 healthy controls. The diabetic children were on a regulated diet and the disease was under good control. The relative contents of linoleic and arachidonic acids were higher in the serum lipids of the diabetics than in the controls as could be expected from the dietary advice given. However, the degree of diabetic control was not significantly correlated to the fatty acid content of any lipid fraction. The serum concentration of apolipoprotein (apo) A-I was directly correlated to the content of polyunsaturated fat and the ratio between polyunsaturated and saturated fatty acids in the triglycerides. The apo A-II concentration was significantly correlated to the ratio between homo-gamma-linolenic and arachidonic acid in all serum lipid esters. No similar relationships were seen among the healthy controls. The different relationships between serum apolipoprotein concentrations and the fatty acid composition in serum in diabetics and controls is compatible with the hypothesis that not only the quantity but also the quality of the serum lipoproteins are different in these two categories of children.

Adolescent↗