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Biomedical subjects

D Adamiker

Publications and source records attributed to D Adamiker.

At least 37 records · Page 2Linked to original sources

Insulin and the in vitro protein synthesis of liver and skeletal muscle ribosomes in experimental acute uraemia.

Tissue dependent alteration of liver and muscle protein synthesis was previously observed in acute uraemia, when intracellular amino acids were used as substrate. Since protein synthesis depends also on substrate availability, it was of interest to investigate the role of isolated liver and skeletal muscle ribosomes of nephrectomized rats and their susceptibility to in vivo insulin stimulation. Under marked uraemic conditions, no difference was demonstrated between controls and uraemic animals; after insulin administration and in the presence of endogenous messenger both liver and muscle ribosomes showed an enhancement of [3H]-phenylalanine incorporation of 20% and 54% respectively in controls, and of 32% and 45% respectively in uraemic rats. This study may rule out the influence of acute uraemia on protein synthesis capacity of isolated ribosomes and emphasize the importance of intracellular amino acid availability in altered protein synthesis.

Acute Disease↗

The effect of a cartilage bone marrow extract on experimentally induced osteoarthrosis in the knee joints of rabbits. A scanning electron microscopic study.

The development of osteoarthrosis following a partial meniscectomy on the knee cartilage of rabbits (Chinchilla hybrids) was monitored with a scanning electron microscope. Simultaneously, a study was made of the effect of the cartilage bone marrow extract Rumalon trademark on the development of the osteoarthrotic changes. Twelve days after the operation, osteoarthrotic changes were evident in the untreated operated joints. After 36 days the damage caused to the cartilage was already radical. The immobility of the operated joint also gave rise to obvious changes in the cartilage of the knee joints which had not undergone an operation. The irregular weight distribution due to the fixation of one joint was apparently enough to provoke degenerative processes on the other side. When the cartilage bone marrow extract Rumalon trademark was administered three times weekly (0.5 mg/kg body weight i.m.) a distinct retardation of the osteoarthrotic development in the early stages was observed. Where the changes had penetrated to the inner cartilage layers, no difference could be established compared to the untreated animals.

Animals↗

[Basal and LH-RH-stimulated gonadotropin release after transport stress in male rats].

A total of 120 male rats of the Sprague-Dawley-strain (6 weeks old) were used in this experiment. 5 groups of 12 animals each were treated intraperitoneally with 200 ng gonadotropin releasing hormone (LH-RH) per animal. 30 minutes later blood was sampled by heart puncture. Group I were animals without transport, group II immediately after, group III one day, group IV one week and group V six weeks after a standardised transport. Another 5 groups were subjected to the same protocol but received saline i.p. instead of LH-RH. Serum levels of LH and FSH were estimated by radioimmunoassay. LH and FSH serum levels could be stimulated by LH-RH in all groups. A significant rise of basal and LH-RH stimulated LH levels was observed until the first day after transport. Thereafter a drop was registered. No consistent patterns of basal as well LH-RH stimulated FSH-levels were noted. These data combine to suggest an elevation of LH-RH secretion as response to the stress. This results in a sensibilisation of the pituitary to exogenous LH-RH.

Animals↗

[Insulin and in vitro protein synthesis of isolated liver ribosomes in experimental acute uraemia (author's transl)].

Liver protein synthesis was shown to be enhanced in acute experimental uraemia, when intracellular amino acids were used as substrate. Since protein synthesis also depends on substrate availability and amino acid concentration is higher in uraemic liver cells, it was of interest to investigate the in vitro protein synthesis capacity of isolated liver ribosomes in the presence of standardized amino acids with and without in vivo insulin stimulation. It was demonstrated that protein synthesis capacity of isolated liver ribosomes remains unaltered in acute uraemia and can be stimulated by in vivo insulin application. Our data suggest that in acute uraemia, intracellular substrate availability plays the essential role in impaired liver protein synthesis.

Acute Disease↗

Maturation of 17 beta-estradiol binding protein in the hypothalamus and anterior pituitary of male rats.

Levels of estrogen binding proteins in the cytosol of hypothalamic and pituitary tissue of male rats at different ages were estimated. Two classes of estrogen binding sites were detected in 13 and 20 days old animals. The number of high affinity estrogen binding sites (K = ca. 2 x 10(-10) mol) of the hypothalamus was slightly larger in 13 days old animals, then decreased to constant levels at the age of 20 days and no changes were observed thereafter. Levels of low affinity binding sites of the hypothalamus (K = ca. 5 x 10(-9) mol) decreased with age and were no longer detectable in 30 days old animals. Similarly, a decrease of low affinity estrogen binding sites with age was recorded for pituitary cytosol samples and this class of receptor sites was no longer observable in 30 days old male rat. At 13 days high levels of high affinity 17 beta-estradiol binding protein was registered and minimal numbers of binding sites were found at 20, 30 and 40 days. Thereafter, the levels remained constant until 100 days and were similar to values observed in the 13 days old male animals. Apparent affinity constants of two classes of binding sites in hypothalamus and pituitary were similar...

Aging↗