Biomedical subjects

M Boll

Publications and source records attributed to M Boll.

At least 19 recordsLinked to original sources

PubMed1990

[Quality assurance in clinical studies: a necessity].

Good Laboratory Practice (GLP), Good Manufacturing Practice (GMP), and Good Clinical Practice (GCP) are the constituents of a new concept for quality assurance in pharmaceutical research. They are to establish standards for preclinical and experimental research in animals (GLP), for the manufacturing of drugs (GMP), and for trials on medical products in human beings (GCP), respectively. Each of the 3 entities is characterized by the same principles of control; these involve written instruction describing the general operations to be performed, the so called Standard Operating Procedures (SOP), and Quality Assurance Units being responsible for surveying the operations in accordance with the SOP, and ensuring that the generated data will satisfy the requirements for quality. As far as clinical trials are concerned, the SOP is represented by the study protocol and a Monitor provides for the surveying of the trial. GCP is further characterized by ethical principles, which aim primarily at protecting personal integrity and welfare of the trial subjects. The Declaration of Helsinki is the accepted basis for clinical trial ethics. Following the Declaration of Helsinki during the planning, conducting, surveying and evaluating of clinical trials provides for a degree of seriousness being the real hallmark of Good Clinical Practice.

Animals↗

PubMed1982

Age-related differences in dietary regulation of lipogenic enzymes in rat liver.

The activity of lipogenic enzymes in rat liver decreases during fasting and is increased on subsequent refeeding. There are considerable age-related differences in the activities of the lipogenic enzymes on dietary manipulation. On refeeding starved animals with either a standard diet or with a high-sucrose, fat-free diet, the increase of the activities was much greater in young animals than in old ones. Old animals exhibited a hyperlipoproteinemia and the activities of their lipogenic enzymes were decreased. The present results, together with reports in the literature, make it likely that the diminished activity of lipogenesis in old animals is a function of adipositas rather than of age.

ATP Citrate (pro-S)-Lyase↗

PubMed1981

Effect of unsaturated fatty acids on the biosynthesis of glucose-repressed enzymes in yeast.

In anaerobically glucose-grown yeast isocitrate lyase (EC 4.1.3.1.), and malate dehydrogenase (EC 1.1.1.37.) are repressed by glucose. 24 h cultures still contain 0.3--0.4% glucose in the medium, which is enough to completely repress these activities. Aeration of these cells, in buffer containing acetate, initiates the formation of the three enzymes. Within 16 h, the specific activities of these enzymes increase about 140, 120 and 70-fold, respectively. Glucose-6-phosphate dehydrogenase activity was not altered. When the yeast was grown anaerobically, but with a supplement of an unsaturated fatty acid in the medium, synthesis of the three enzymes was much faster and the specific activities after 16 h of derepression were considerably higher. A relationship exists between the number of double bonds in the unsaturated fatty acid molecule and its capability to stimulate enzyme synthesis: linolenic acid is more effective than linoleic acid, which, in turn, is much more effective than oleic acid. Increasing periods of aeration with glucose of anaerobically grown cells prior to derepression results in an increasing stimulation of enzyme synthesis on subsequent derepression. Anaerobic incubation of yeast in the presence of an unsaturated fatty acid in advance to derepression also increased the velocity of enzyme formation. It is suggested that during the aeration period with glucose and during anaerobic incubation with an unsaturated fatty acid a more active protein synthesizing apparatus was formed.

Fatty Acids, Unsaturated↗

PubMed1980

Effect of unsaturated fatty acids on sterol biosynthesis in yeast.

Lipid-depleted yeast, grown anaerobically, contains only very low amounts of sterols. The hydroxymethylglutaryl-CoA reductase activity, the regulatory enzyme of sterol synthesis in yeast, is also low. Aeration of such cells in a buffer containing a carbon source induces hydroxymethylglutaryl-CoA reductase activity and increases sterol synthesis. The velocity of the increase depends on the carbon source present during the aeration period. Glucose and sugars that are easily converted to glucose were found to be most effective. A supplement of unsaturated fatty acids during anaerobic growth causes a several-fold greater velocity of the enzyme induction and of sterol biosynthesis. Linolenic acid (30 microM) accelerated sterol biosynthesis about 7-fold. Activities of galactokinase and galactose-1-phosphate uridyltransferase, which are involved in the conversion of galactose to glucose, increased several-fold in the supplemented cells within 6 h of aeration, concomitantly with stimulation of sterol synthesis from galactose. It is suggested that the stimulation of enzyme induction and sterol biosynthesis in fatty acid supplemented cells is due to a completion of the protein-synthesizing apparatus during cell growth. A markedly enhanced capacity of these cells to incorporate leucine into acid-precipitable protein supports this assumption.

Acetates↗

PubMed1979

Immunotitration of alkaline phosphatase isozymes in normal and pathological urine.

Isoenzyme patterns of alkaline phosphatase are determined quantitatively in extracts of human kidney as well as in human urine by means of immunotitration technique. Both media contain two types of AP isoenzymes: liver and intestinal like AP. Intestinal AP is located as a minor component of total AP activity (1-4%) in particle-free fraction of the kidney. Urinary AP activity is found after high speed centrifugation in supernatant (100,000 Xg) as well as in the 100,000 Xg sediment and can only be made soluble from the latter by n-butanol treatment. Intestinal AP in urine is concentrated in the supernatant while in sediment the isoenzyme pattern resembles to that of kidney. Urine of normal persons contains most of AP activity in the sediment and consists mainly of liver type AP. Urinary AP of patients with renal diseases or after application of cytotoxins contains little sedimentable activity, mainly intestinal AP.

Alkaline Phosphatase↗

PubMed1975

Sterol biosynthesis in yeast. 3-Hydorxy-3-methylglutaryl-Coenzyme A reductase as a regulatory enzyme.

Anaerobically and aerobically grown yeast contains 3-hydroxy-3-methylglutaryl-CoA reductase, which is located in the mitochondrial fraction of the cell. Anaerobically grown yeast has a low specific activity of 3-hydroxy-3-methylglutaryl-CoA reductase and a low sterol content. Aeration of this yeast in buffer, without growth, results in an increase in the specific activity of the enzyme, which is paralleled by an increase in the sterol content. This induction has an oscillatory profile with yeast grown anaerobically for 24 h and a linear pattern with cells grown anaerobically for 72 h. With the latter type of yeast, glucose is necessary for an induction, whereas with the other yeast an induction occurs with and without glucose. By an anaerobic incubation in buffer of the yeast grown anaerobically for 24 h, the oscillatory profile can be transformed into a linear one. The extent of induction of the reductase is strictly dependent on the concentration of glucose present. Sterols increase in whole cells, but they do not increase in the mitochondrial fraction. The induction of 3-hydroxy-3-methylglutaryl-CoA reductase is strongly inhibited by cycloheximide, but is not affected by chloramphenicol. The induction of the enzyme is closely connected with the glucose metabolism of the cell; fructose, mannose, and ethanol can also induce the reductase.

Aerobiosis↗

PubMed1974