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Biomedical subjects

B G Jacob

Publications and source records attributed to B G Jacob.

15 recordsLinked to original sources
PubMed1993

[Effect of three antihypertensive drug groups on lipid metabolism. Effects of alpha receptor blockers, central sympatholytic drugs and vasodilators].

Basic remarks and aims: Alpha-receptor blockers, central sympathicolytic agents and vasodilators are all drugs that are often used to treat hypertension. On the basis of a study of the literature, the effects of these groups of substances on lipid metabolism are described. Main points discussed: Although the data available are few, vasodilators, in particular dihydralazine and hydralazine appear to have no unfavorable effect on serum lipids. Nor do the centrally acting alpha-receptor agonists, such as methyldopa and clonidine have any unfavorable effect, with the exception of the decrease in the HDL cholesterol observed under methyldopa. The selective alpha-1-receptor blockers, prazosin, doxazosin and urapidil, even have a positive effect of varying degree on lipid metabolism: increase in HDL cholesterol and decrease in triglycerides. Long-term studies over a number of years are, however, lacking. The effect of labetalol, reserpine and guanethidine on lipid metabolism cannot yet be definitively assessed owing to a lack of data.

Adrenergic alpha-Antagonists↗
PubMed1993

Therapy of severe familial heterozygous hypercholesterolemia by low-density lipoprotein apheresis with immunoadsorption: effects of the addition of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors to therapy.

To establish whether additional therapy with 3-hydroxy-3-methylglutaryl (HMG) coenzyme A (CoA) reductase inhibitors enhances the low-density lipoprotein (LDL) cholesterol lowering effect of LDL apheresis with immunoadsorption in the treatment of patients with familial heterozygous hypercholesterolemia and coronary artery disease we studied eight patients initially on immunoadsorption therapy alone for 3 years. The adding of HMG CoA reductase inhibitors decreased pretreatment LDL cholesterol from 6.76 +/- 0.98 to 4.97 +/- 0.98 mmol/l and posttreatment LDL cholesterol from 2.33 +/- 0.80 to 1.94 +/- 0.67 mmol/l and increased pre- and posttreatment high-density lipoprotein (HDL) cholesterol by 0.08 and 0.13 mmol/l respectively. The LDL/HDL ratio was reduced from 4.0 to 2.8 (prior to any therapy the ratio was 13.4). The increase in LDL cholesterol between weekly treatments was less steep under the combined therapy. At the same time the treated plasma volume during LDL apheresis could be decreased from 5070 +/- 960 to 4370 +/- 1200 ml. We conclude that in patients with severe familial heterozygous hypercholesterolemia LDL apheresis should be combined with HMG CoA reductase inhibitors.

Adult↗
PubMed1993

Three-year treatment of familial heterozygous hypercholesterolemia by extracorporeal low-density lipoprotein immunoadsorption with polyclonal apolipoprotein B antibodies.

Familial hypercholesterolemia is a disorder of lipid metabolism associated with a highly increased risk for cardiovascular disease. Since in such patients even combined drug therapy often fails to decrease low-density lipoprotein (LDL) cholesterol levels sufficiently, extracorporeal LDL elimination has been developed. We treated eight adult patients with LDL immunoadsorption using antibodies against apolipoprotein B without additional lipid-lowering drug therapy for 3 years; this procedure was performed at weekly intervals. By one treatment session, LDL cholesterol and lipoprotein(a) levels were decreased by 55%. Under regular treatment, mean LDL cholesterol levels of 165 mg/dL between two consecutive treatment sessions could be reached, compared with 522 +/- 24 mg/dL before any treatment. As high-density lipoprotein (HDL) cholesterol levels increased under regular treatment, the LDL/HDL cholesterol ratio decreased from 13.4 to 3.4. Positive influences on plasma and whole-blood viscosity as well as on erythrocyte aggregation also seem to be beneficial with regard to retarding atherosclerosis. Very-low-density lipoprotein (VLDL) levels were reduced by approximately 50% after treatment, accompanied by a marked increase of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) activity. The effects of LDL apheresis on hemostasis, complement activation transport proteins, and hematological parameters were found to be small. In addition, no side effects amounting to any major clinical relevance occurred in any of the patients. After 3 years of LDL apheresis, a decrease in the frequency of anginal chest pain and ST segment depression on exercise testing and a marked reduction of tendon xanthoma size were observed.

Adult↗
PubMed1993

Long-term treatment (2 years) with the HMG CoA reductase inhibitors lovastatin or pravastatin in combination with cholestyramine in patients with severe primary hypercholesterolemia.

The effects of the two HMG CoA reductase inhibitors lovastatin and pravastatin in combination with 12-16 g cholestyramine on serum lipids were studied in 18 patients with severe primary hypercholesterolemia. Combined therapy of cholestyramine with lovastatin (80 mg daily) decreased low-density-lipoprotein (LDL) cholesterol by 44% (baseline 7.65 +/- 0.51 mM) and increased high-density-lipoprotein (HDL) cholesterol by 20% (baseline 1.22 +/- 0.12 mM) in 9 patients after 2 years. In 9 other patients with comparable baseline lipid values, cholestyramine plus pravastatin (40 mg daily) reduced LDL cholesterol to a comparable extent after 2 years (-43%, baseline 7.71 +/- 0.44 mM) and increased HDL cholesterol by 18% (baseline 1.06 +/- 0.11 mM). The combination with lovastatin led to a significant reduction in triglycerides level by 25% (baseline 1.63 +/- 0.24 mM), whereas the combination with pravastatin did not change triglycerides level (baseline 1.39 +/- 0.15 mM). Both drug regimens were well tolerated without serious side effects. The effects of both HMG CoA reductase inhibitors after 2 years were comparable to those after short-term intake and after 1-year therapy without loss of efficacy.

Adult↗
PubMed1992

Short- and long-term effects of lovastatin and pravastatin alone and in combination with cholestyramine on serum lipids, lipoproteins and apolipoproteins in primary hypercholesterolaemia.

The effects of the HMG CoA reductase inhibitors lovastatin and pravastatin on serum lipids, lipoproteins and apolipoproteins have been studied in 35 patients with primary hypercholesterolaemia. LDL cholesterol was lowered to the same extent by both agents compared on a mg basis of each drug per day. HDL cholesterol was increased by lovastatin but not by pravastatin. The reduction in serum triglycerides, VLDL triglycerides and VLDL cholesterol was more pronounced after lovastatin than pravastatin. After 1 year the effect of combined treatment with 40 mg pravastatin and 8 g cholestyramine on the reduction in LDL cholesterol (-39%) in 13 patients was comparable to that of 80 mg lovastatin plus 8 g cholestyramine (-40%) in 12 patients with identical baseline values. Differences were also found in the effects of the combination therapy with the two drugs on HDL cholesterol, serum triglycerides, VLDL triglycerides, VLDL cholesterol, and apolipoproteins.

Adolescent↗
PubMed1992

Treatment of primary chylomicronemia due to familial hypertriglyceridemia by omega-3 fatty acids.

Primary familial forms of chylomicronemia can lead to acute life-threatening complications, especially acute pancreatitis. The main aim of therapy is to avoid this so-called chylomicronemia syndrome. In 12 patients with primary chylomicronemia due to familial hypertriglyceridemia, the addition of 2.16 g omega-3 fatty acids over 4 weeks and 4.32 g for 8 weeks resulted in a decrease of serum triglyceride levels from 1,624 +/- 333 to 894 +/- 241 mg/dL after 12 weeks. Cholesterol and triglyceride levels in the chylomicron fraction were reduced concomitantly, the apolipoprotein B-100/B-48 ratio increased, very--low-density lipoprotein (VLDL) triglycerides, VLDL cholesterol, and total cholesterol levels decreased, and low-density lipoprotein (LDL) cholesterol showed a tendency to increase, but this finding did not reach significance. High-density lipoprotein (HDL) cholesterol levels remained unchanged, as did the levels of apolipoproteins A-I, A-II, and E, and lipoprotein(a). Apolipoprotein B levels decreased significantly. The decrease of triglyceride levels to still-elevated concentrations was accompanied by a substantial decrease in plasma and whole-blood viscosity and erythrocyte aggregation, which reached normal values. As in chylomicronemia, complications usually occur at triglyceride levels higher than 1,500 mg/dL; patients can still profit from treatment with omega-3 fatty acids, even though triglyceride levels are still substantially elevated. No clinically relevant side effects occurred, with the exception of the manifestation of diabetes mellitus in one patient, which could be reversed after discontinuation of treatment.

Adult↗
PubMed1991

Comparative effects of two HMG-CoA reductase inhibitors (lovastatin and pravastatin) on serum lipids and lipoproteins.

The effects of the HMG-CoA reductase inhibitors lovastatin and pravastatin were studied over 4 months on serum lipids and lipoproteins in 35 patients with severe primary hypercholesterolaemia. In 17 patients 20 mg of lovastatin/day lowered the total cholesterol level by 18% (baseline 373 mg/dl) and LDL cholesterol by 20% (baseline 300 mg/dl). The corresponding data for 40 and 80 mg of lovastatin/day were respectively -23% and -29% for total cholesterol, and -30% and -36% for LDL cholesterol. Pravastatin at 20 mg/day lowered the total cholesterol in 18 patients by 20% (baseline 373 mg/dl) and LDL cholesterol by 24% (baseline 307 mg/dl). The corresponding data for 40 mg of pravastatin per day were 24% for total cholesterol and 30% for LDL cholesterol. So the effects of both HMG-CoA reductase inhibitors on total and LDL cholesterol are comparable. HDL (high-density lipoprotein) cholesterol was increased by lovastatin, whereas pravastatin showed no influence on HDL cholesterol. The reduction of serum triglycerides, VLDL triglycerides and VLDL cholesterol was more pronounced under treatment with lovastatin than under pravastatin.

Cholesterol↗
PubMed1990

Insulin inhibits lipolytic activity and degradation of beta-lipotropin in rabbit adipose tissue.

beta-Lipotropin, a pituitary peptide, is a potent stimulator of lipolysis in rabbit adipose tissue in vitro and in vivo. Insulin inhibited the beta-lipotropin (1-100 nM)-stimulated glycerol release from rabbit adipocytes and fat pads significantly at concentrations of 10 and 100 microM. Both these concentrations of insulin also decreased the degradation of beta-lipotropin in intact adipose tissue to the same extent as the lipolytic activity. Furthermore, insulin reduced the degradation of beta-lipotropin in rabbit adipose tissue homogenate. Like insulin, several lysosomotropic agents also decreased significantly the degradation and the lipolytic activity of beta-lipotropin. On the other hand, insulin-like growth factor I in lower concentrations (1-100 nM) did not effect degradation and lipolytic activity of beta-lipotropin in rabbit adipose tissue. Thus, a direct influence of insulin on lysosomal enzymes degrading beta-lipotropin in rabbit adipose tissue can be suggested.

Adipose Tissue↗
PubMed1990

Processing of the lipid-mobilizing peptide beta-lipotropin in rabbit adipose tissue.

beta-Lipotropin, a pituitary peptide, is a strong stimulator of lipolysis in rabbit adipose tissue. This polypeptide is shown to be degraded by intact fat pads, homogenized adipose tissue and adipocytes of the rabbit dependent on the amount of adipose tissue, time and the pH of the incubation medium. In subcellular fractions of rabbit adipocytes the proteolytic activity could be localized into the cytosol and the microsomal fraction. To obtain information about the processing of beta-lipotropin in its target cell lipolysis and degradation of this polypeptide were investigated in the presence of inhibitors of distinct cellular mechanisms and in different physiological states such as obesity and starvation. Thus, the stronger lipolytic response in adipocytes from obese rabbits respectively animals fed ad libitum was accompanied by a significantly increased degradation in comparison to lean respectively starved rabbits. The six lysosomotropic agents (chloroquine, NH4Cl, propranolol, quinacrine, acridine orange and tetracaine), the proteinase inhibitors alpha 2-macroglobulin and monodansylcadaverine, cellular ATP depletion by 2-deoxy-D-glucose and 2,4-dinitrophenol and the omission of Ca2+ ions from the incubation medium inhibited dose-dependently the lipolytic activity as well as the degradation of beta-lipotropin in intact and homogenized adipose tissue. Inhibitors of the cytoskeleton such as colchicine, cytochalasin B, vinblastine and concanavalin A also reduced lipolysis but only the degradation in intact adipose tissue. It can be concluded that after receptor-mediated uptake the cytoskeleton and lysosomal proteases are involved in the processing of beta-lipotropin.

Adipose Tissue↗