Biomedical subjects

S Stroh

Publications and source records attributed to S Stroh.

4 recordsLinked to original sources

PubMed1997

Nutrition and cardiovascular disease.

The association between nutrition and coronary heart disease is mainly due to the effect of nutrients on serum lipids and lipoproteins. Cholesterol intake does not play a very important role for plasma cholesterol although there is a strong interindividual difference in response. The intake of saturated fatty acids strongly negatively affects plasma low-density lipoprotein cholesterol concentration while mono- and polyunsaturated fatty acids are generally regarded as beneficial. Omega-3 fatty acids mainly decrease triglyceride concentration while omega-6 polyunsaturated fatty acids mainly affect low-density lipoprotein cholesterol. Other nutrients which affect risk for coronary heart disease are dietary fiber, calcium, magnesium, iron, antioxidants as well as vitamins. Dietary fiber decrease intake of calories and fat, while iron and antioxidants play a role in oxidative modification of low-density lipoproteins. A low intake would lead to an accelerated uptake of low-density lipoprotein into the macrophage. Yet, intervention studies have not shown conclusively the benefit of a high-dose supplementation of the antioxidants vitamin E or beta-carotene on coronary heart disease. Homocysteine plasma concentration is influenced by folate as well as vitamin B6 and B12. Whether a high-dose supplementation with these substances does not only decrease plasma concentrations of homocysteine but also positively influence the course of coronary heart disease remains to be established.

Animals↗

PubMed1993

Influence of a single parenteral application of a 10% fish oil emulsion on plasma fatty acid pattern and the function of thrombocytes in young adult men.

50 ml of a 10% fish oil emulsion (41% omega-3 fatty acids of total fatty acids) were infused for 1 h into the arm vein of young, healthy, male volunteers. The fatty acid composition of the plasma, aggregation of the blood platelets as well as the thromboxane synthesis, were measured before the beginning of infusion, 20, 60, 120, 360 and 1,440 min after the start of the fat infusion. In the first 60 min, the fatty acid composition of the plasma changed in correspondence with the supplied fatty acid pattern. At the end of the investigation it was again within the normal range. As a result of fat application thromboxane synthesis was reduced and the aggregation of the platelets was inhibited but it was normalized by the 1,440-min value. Fish oil emulsions might be beneficial for parenterally fed patients with a high risk of thrombosis. Therefore the performance of further investigations using a varying dosage and multiple application can be recommended.

Adult↗

PubMed1991

[In vitro studies of the effect of different mixture proportions of omega-3 and omega-6 fatty acids on thrombocyte aggregation and thromboxane synthesis in human thrombocytes].

In order to estimate the influence of the tested fatty acids on platelet aggregation, synthesis of prostaglandin E and thromboxane B in vitro, platelet rich plasma (PRP) was incubated with the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with linoleic acid as representative of the omega-6 fatty acids, as well as with mixtures of EPA and DHA and all fatty acids, resp., with and without addition of alpha-tocopherol. For the determinations, platelets were prepared from blood of young adult male volunteers (age 26.6 +/- 8 years). Platelet aggregation and synthesis of thromboxane were measured after 30 and 60 min of incubation. Smoking habits were not regarded. The incubation of platelets with DHA and EPA itself, as well as the mixture of fatty acids dominated by omega-3 fatty acids (omega-3/omega-6 = 15/1) caused a significant decrease (p less than 0.05) of collagen-induced platelet aggregation. Tocopherol, linoleic acid, and the linoleic-acid-rich mixtures (omega-3/omega-6 = 1/4) caused only a slight inhibition of platelet aggregation. No uniform influence of omega-3 fatty acids could be observed that showed their influence on synthesis of thromboxane to be of importance for the promotion of platelet aggregation. EPA and the mixture of EPA and DHA did decrease thromboxane synthesis significantly (p less than 0.05). On the other hand, single incubation with DHA as well as with linoleic acid rich mixtures caused a statistically not significant increase of rate of the synthesis, which did not increase the aggregation. This observation indicates the formation of less effective TXA3. An influence of tocopherol could also not be observed.

Adult↗

PubMed1991

Respiratory chain proteins.

Mammalian mitochondrial DNA codes for 13 proteins, which are all components of energy transducing enzyme complexes of the respiratory chain, i.e. the complexes which translocate protons across the inner mitochondrial membrane. The number of subunits of these enzyme complexes increase with increasing evolutionary stage of the organism. The additional nuclear coded subunits of the enzyme complexes from higher organisms are involved in the regulation of respiration, as demonstrated by the influence of intraliposomal ATP and ADP on the reconstituted cytochrome c oxidase (COX) from bovine heart. This regulation is not found with the reconstituted enzyme from P. denitrificans, which lacks the nuclear coded subunits. Some of the nuclear coded subunits occur in tissue-specific isoforms, as reported for COX and NADH dehydrogenase. Tissue-specific regulation of COX activity is also demonstrated by the differential effects of intraliposomal ADP on the kinetics of reconstituted COX from bovine liver and heart, which differ in subunits VIa, VIIa and VIII. At least 3 different COX isozymes occur in bovine liver, heart or skeletal muscle and smooth muscle. An evolutionary relationship between COX subunits VIa and VIc and between VIIa and VIIb is suggested based on the crossreactivity of monoclonal antibodies, amino acid sequence homology and hybridization at low stringency of PCR-amplified cDNAs for subunits VIa-1, VIa-h and VIc from the rat.

Amino Acid Sequence↗