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Biomedical subjects

K Keller

Publications and source records attributed to K Keller.

At least 127 records · Page 7Linked to original sources
PubMed1979

[Diagnosis of bacterial endocarditis involving three valves by echocardiography (author's transl)].

Endocarditis was suspected in a 66-year-old man who had enterococcal septicaemia. Thrombotic involvement of the mitral, aortic and tricuspid valves by the endocarditis was demonstrated by echocardiography, the diagnosis and localisation of the endocarditic deposits being confirmed at necropsy, the patient's condition making operative treatment impossible. The characteristic echocardiographic finding was of abnormal echos from the valves with largely normal valve movements. Atrial myxoma and artefacts had to be considered in the differential diagnosis.

Aged↗
PubMed1978

Release of glycolytic enzymes from cultivated tumor cells.

Several types of cultured cells release glycolytic enzymes into their suspending medium. This effect is most obvious with tumor cells, especially with their ascites forms. Erythrocytes do not release glycolytic enzymes. The total extracellular phosphoglucose isomerase activity consists of two components. One part is dissolved in the medium, the other one is sedimentable at 150 X g together with the cells. The latter seems to be localized at the cell surface. At densities of about 10(6) cells/ml maximum activity in the medium is reached within 5--10 min. After that no further release of enzyme activity can be observed. Serum reduces the rate of enzyme release considerably. This effect can be reversed by washing with protein free media. Treatment with trypsin leads to high extracellular phosphoglucose isomerase activities of the cells which originally show low external enzyme activity. Erythrocytes do not show any effect with trypsin, ascites tumor cells do not alter their high extracellular enzyme activity. At a density of 10(5) cells/ml, Yoshida acites tumor cells, cultured in vitro, release about 12% of originally intracellular phosphoglucose isomerase activity by 5 elutions with fresh medium. The process of enzyme release shows a certain selectivity in respect to different glycolytic enzymes. Aldolase exhibits the highest activity in the medium in relation to its homogenate activity.

Animals↗
PubMed1978

Correlation between serum concentration and pharmacological effect on atrioventricular conduction time of the antiarrhythmic drug propafenone.

Seven patients with cardiac dysrhythmias received a single, oral, therapeutically effective dose of the antiarrhythmic drug propafenone. The serum levels correlated well with changes in atrioventricular conduction times during the postabsorptive elimination phase (r = 0.8610, p less than 0.001). The mean half-lives of the serum level and the electrocardiographic effect (PQ-time) were 3.6 +/- .2 h and 3.8 +/- 0.6 h, respectively.

Adult↗
PubMed1978

Effects of 6-aminonicotinamide on growth and acetylcholinesterase activity during differentiation of neuroblastoma cells in vitro.

Addition of 6-AN (0.01 mg/ml) to growing cultures of C-1300 neuroblastoma cells strongly reduced cell division. This growth inhibition was accompanied by a higher cell volume and a lower protein content per cell as compared to controls. Concurrently the specific activity of AChE increased markedly incontrols and 6-AN-treated cultures. During the experimental periods the specific activity of AChE was significantly higher after 6-AN. Morphologically, 6-AN-treated cultures showed characteristic signs of differentiation, i.e. enlarged, flattened cells with long branched processes. The described effect of 6-AN on growth and differentiation of neuroblastoma cells was less pronounced if cells received the antimetabolite after a subcultivation period of 5 days.

6-Aminonicotinamide↗
PubMed1978

Evaluation of the effectiveness of a high school course in cardiovascular nutrition.

High school biology students participated in a cardiovascular nutrition education program. The program was evaluated for its effect on the student's knowledge, attitudes, reported eating behavior, and serum lipid levels by matching individual's pre-and post-program results. There was a significant improvement in cardiovascular nutrition knowledge and attitudes toward a low cholesterol pattern of eating. There was also a signigicant improvement in reported eating patterns. However, the rise in serum cholesterol levels one year later did not differ from the rise in serum cholesterol levels in a control school. Improvement in attitudes and reported eating behavior was significantly greater for students whose initial cholesterol level was in the upper quartile of U.S. 16-year olds.

Adolescent↗
PubMed1978

[Antiarrhythmic effect of propafenone in relation to serum concentration and conduction time (author's transl)].

7 patients with stable cardiac dysrhythmias (ectopic beats of ventricular origin) received a single oral dose of 900 mg Propafenone. Besides the antiarrhythmic effect of propafenone the effect on changes of PQ- and QRS duration as well as the corresponding serum concentration was measured. A significant correlation between changes of PQ-time and serum concentration (r = 0.6810, p less than 0.001) was found. The half-life of serum level was 3.6 +/- 0.2 h, that of PQ-time prolongation 3.8 +/- 0.6 h. A complete suppression of all ectopic beats has been achieved in all treated patients for 6--8 hours.

Adult↗
PubMed1977

Distribution of acridine orange-stained RNA in neuroblastoma cells during differentiation.

Vital staining of neuroblastoma cells with acridine orange produces a bright intracellular red-orange fluorescence most probably due to the occurrence of RNA. The distribution of this fluorescence depends on the state of morphological differentiation. The fluorescence is predominantly found in the perikaryon, the growth cones, and the endings of the processes of differentiated cells. This is of special interest in respect to the biochemistry of differentiation and the function of nerve cells. Comparative autoradiographical studies with 3H-uridine demonstrate that the newly synthesised RNA is transported into the endings of the cell processes.

Acridines↗
PubMed1977

Glucose metabolism in C-1300 neuroblastoma cells after inhibition of hexose monophosphate pathway.

1. Application of 6-AN (0.01 mg/ml) leads to a strong accumulation of 6-PG in C-1300 neuroblastoma cells which, however, only amounts to one third of that found in C-6 glial cells. 2. In C-1300 neuroblastoma cells dephosphorylation of the accumulated 6-PG causes a rise of the intracellular gluconate to eight times the value found for 6-PG. It is four times higher than the gluconate content observed in C-6 glial cells. 3. Although 6-PG is a competitive inhibitor of PGI it causes no reduction of glycolytic flux and ATP content in stationary phase C-1300 neuroblastoma cells in contrast to the strong reduction of glycolytic flux and ATP content observed in C-glial cells. 4. The intracellular Glc-6-P and Fru-6-P content of C-1300 neuroblastoma cells increases by four to five times after treatment with 6-AN. Both this increase and the decrease of Fru-1,6-P2 content point to an inhibition of the phosphofructokinase. 5. In contrast to C-6 glial cells no morphological changes could be observed in C-1300 neuroblastoma cells up to 24 h after administration of 6-AN.

6-Aminonicotinamide↗