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Biomedical subjects

M Keller

Publications and source records attributed to M Keller.

At least 217 records · Page 12Linked to original sources
PubMed1981

Beta 2-microglobulin and other proteins as parameter for tubular function.

Urinary excretion of the low molecular weight protein beta 2-microglobulin and tubular enzymes--alanine aminopeptidase (AAP), gamma-glutamyl transpeptidase (gamma-GT) and alkaline phosphatase (AP)--are very sensitive parameters for proximal tubular lesions. In patients with preeclampsia the renal excretion of beta 2-microglobulin allows to differentiate between a primary preeclampsia and a preeclampsia superimposed upon chronic pyelonephritis. In the first group the increase is 3- to 4-fold and in the second group up to 300-fold. In patients with kidney transplantation the urinary excretion of beta 2-microglobulin, AAP, gamma-GT and AP are several times higher than in normals. In case of a rejection episode a further increase of these proteins occur in more than 80% several days before clinical symptoms are present. The application of analgetics (paracetamol, acetylsalicylic acid) in healthy individuals in therapeutical dosages on 3 consecutive days does not show any tubular alteration by the measurement of urinary beta 2-microglobulin. Aminoglycosides (tobramycin, UK 18,892) lead to a cumulative increase of the renal excretion of beta 2-microglobulin and AAP while cephalosporins induce an increase of total proteins in the final urine under the same conditions.

Acetaminophen↗
PubMed1980

Hybridization of bean, spinach, maize and Euglena chloroplast transfer RNAs with homologous and heterologous chloroplast DNAs. An approach to the study of homology between chloroplast tRNAs from various species.

Chloroplast tRNAs from two dicotyledons (spinach and bean), a monocotyledon (maize) and a green alga (Euglena) have been fractionated by two-dimensional gel electrophoresis. The individual tRNAs have been identified, albeled with 125I or 32P, and used in tRNA-DNA hybridization experiments. Spinach chloroplast tRNAs hybridize as well, and maize chloroplast tRNAs almost as well as bean chloroplast tRNAs to bean chloroplast DNA, thus suggesting a high degree of homology between the chloroplast tRNAs from the two dicotyledons and between the tRNAs from the two dicotyledons and those of the monocotyledon. But Euglena total chloroplast tRNA hybridizes very poorly to bean chloroplast DNA, and among the 14 individual tRNAs tested, only one, Euglena chloroplast tRNAPhe, hybridizes to both maize and bean chloroplast DNAs, which is in good agreement with the fact that Euglena and bean chloroplast tRNAsPhe have almost identical primary structures.

Amino Acids↗
PubMed1980

Probucol in hypercholesterolemia. A double blind study.

The effect of Probucol on serum lipids, lipoproteins and the apoproteins A1, A2 and B was studied in 27 patients with primary hypercholesterolemia. After 3 months of dietary treatment and a 6 week placebo period the patients received 4 X 250 mg of Probucol or placebo per day for 4 months in a double blind design. Total and LDL-cholesterol were significantly reduced with Probucol (13% and 16% respectively) in addition to the diet. Apo B showed a 12% decrease. The HDL cholesterol concentration as well as the serum triglycerides and triglyceride-rich lipoproteins were not significantly altered. Both apo A1 and apo A2 were markedly reduced under Probucol treatment. In general the subjective and objective tolerance of the drug was good.

Adult↗
PubMed1979

Fractionation and identification of spinach chloroplast transfer RNAs and mapping of their genes on the restriction map of chloroplast DNA.

Spinach chloroplast 4S RNAs has been separated by two-dimensional polyacrylamide gel electrophoresis into about 35 species. After extraction from the gel, 27 of these RNA species were identified by aminoacylation as tRNAs specific for 16 amino acids. Individual tRNAs were labeled in vitro with 125I and hybridized to DNA fragments obtained by digestion of spinach chloroplast DNA with KpnI, PstI, SalI and XmaI restriction endonucleases. A minimum of 21 genes corresponding to tRNAs for 14 different amino acids have been localized on the restriction endonuclease cleavage site map of the DNA molecule. Of these, 15 genes corresponding to tRNAs for 12 amino acids are located in the larger of the two single-copy regions which separate the two inverted copies of the repeat region. Each copy of this repeat region contains a set of genes for the ribosomal RNAs and a gene for tRNA2Ile in the "spacer" sequence between the 16S and 23S ribosomal RNAs. The genes for tRNA1Ile, tRNA2Leu and tRNA3Leu also map in the repeat region, but outside the ribosomal DNA unit. At present, two more chloroplast tRNAs (for Pro and Lys) have been identified, but not mapped, while 4 unidentified 4S RNAs have been mapped in the large single-copy region of the DNA molecule. Evidence is presented that isoaccepting tRNA species can be transcripts from different loci.

Amino Acyl-tRNA Synthetases↗
PubMed1979

Treatment of hypertrophic obstructive cardiomyopathy with verapamil.

Twenty-two patients with hypertrophic obstructive cardiomyopathy were treated with the calcium inhibitor, verapamil, which was administered in a mean oral dose of 480 mg per day. After an average of 15 months of treatment (4 to 24 months), the QRS amplitude in the electrocardiogram was significantly reduced from 4.2 to 3.8 mV. Heart volume calculated from chest x-ray films in the supine position decreased significantly from 858 to 766 ml per 1.73 m2. In 10 patients, follow-up heart catheterisation showed a decrease in left ventricular muscle mass in 7 patients and a slight increase in 3 patients. Coronary artery diameter decreased in 7 patients, increased in 1, and was unchanged in 2. The reduction in coronary artery diameter is considered to be a consequence of a reduced heart muscle mass. From all available clinical data it is concluded that verapamil treatment is superior to beta-blocker therapy.

Adult↗
PubMed1979

Absorbance measurement in cuvettes lying longitudinal to the light beam.

Measurement in cuvettes with their longitudinal dimension parallel to the light beam, while under the influence of a centrifugal force, has many advantages that are not immediately apparent. This survey summarizes the advantages in comparison to cuvettes standing with their long axis perpendicular to the light beam: in the latter the pathlength is fixed by the geometry, but if the cuvette is lying longitudinal to the light beam the pathlength is given by the filling volume. Because of the dependence of the pathlength on the filling (reaction) volume when cuvettes are lying longitudinal to the light beam, the calculation formulas show that the calculation factors, both for enzyme and substrate determination, become independent of the reagent volume form. This is demonstrated by simple equations and confirmed in practice by use of the (Cobas) Bio centrifugal analyzer in assays for glucose and aspartate aminotransferase.

Aspartate Aminotransferases↗
PubMed1978

A comparison between intragastric titration and aspiration technique under basal conditions and after food or pentagastrin stimulation.

A total of 16 healthy subjects had gastric secretory studies where acid was either measured by the conventional aspiration technique (AT) or by intragastric titration at a pH of 5.0 (IT). In a first study food- and pentagastrin-stimulated PAO levels, both measured by IT, were within similar ranges. However, as compared to the respective AT data of the same subjects, the mean IT results were 35% higher, although both values were well correlated. In a second study a similar difference was observed between IT and AT data throughout the whole range of the pentagastrin dose-response curve. Both curves followed Michaelis-Menten kinetics and had similar Km values, while Vmax values were significantly higher at IT. This constellation excludes an increase of the gastrin sensitivity of the parietal cells as a cause for the higher IT data. It is, however, in keeping with the hypothesis that the distension stimulus present at IT potentiates the pentagastrin-stimulated acid secretion. It is likely that methodological problems such as overtitration of acid at IT and transpyloric loss of acid at AT additively contribute to the relatively large difference between AT and IT values. It is therefore not possible to fully interchange AT and IT data, despite their good correlation.

Adult↗
PubMed1977

[Cranial mucormycosis in a patient with a transplanted kidney].

Mucormycosis is a very serious complication of debilitating diseases, and particularly of diabetes. Presently the treatment of choice is amphotericine B. A patient is described who, like most other renal transplant patients with mucormycosis, had cranial localization of this disease and diabetes. The clinical findings were classical and the diagnosis was confirmed histologically.

Adult↗