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Biomedical subjects

G Kremer

Publications and source records attributed to G Kremer.

27 records · Page 2Linked to original sources

[Mass rearing of the Pharoah's ant Monomorium pharaonis].

New techniques for the mass rearing of the Pharaoh's ant (Monomorium pharaonis) are described. The basic idea in doing this is the enlargement of the surface of the rearing containers in order to guarantee the lapse of normal behaviour such as the search for food and recruitment. The rearing container is an aquarium inside of which a great number of levels of glass are located, which are connected with each other. The watering of the colonies is effected by wet cotton wool in petridishes in the lower parts of the rearing devices. A transposition of the colonies in intervals of 6 to 8 months is recommended. A dispersation method of great colonies to small and physiologically equal laboratory colonies is described. A further mass rearing device allowes a strong enlargement of the surface of normal rearing dishes of 20 to 30 cm in diameter. The basic principle consists in the setting into each other of separate dishes. To prevent an outbreak from these rearing containers the walls are prepared with residues of talcum powder. The methods and devices mentioned make it possible to produce great masses of experimental material under constant control of the developmental status at low costs and little need of space.

Animals↗

Correlation between isoprenaline-stimulated synthesis of cyclic AMP and occurrence of beta-adrenoreceptors in immature erythrocytes from rats.

When increasing reticulocytosis (up to 80%) was induced in rats by treatment with acetyl-phenylhydrazine (up to 70 mg/kg on 3 consecutive days) synthesis of cAMP stimulated by isoprenaline in intact red blood cells and in the related membrane preparations increased up to 100-fold. At the same time the density of beta-adrenoreceptor sites (measured by ligand binding with (3H)(-)-dihydroalprenolol) in the related membrane preparations was only increased about 5-fold. There was however a linear correlation between the increase of isoprenaline-stimulated enzyme activity and the receptor density in membrane preparations. The results indicate that mature red cells contain beta-adrenoreceptor sites but little or not adenyl cyclase activity. Thus, during the maturation process of these cells, enzyme activity and receptor densities decrease at different speeds indicating a different turnover of these two entities of the cytoplasmic membrane.

Adenylyl Cyclases↗

[Studies on the incidence and clinical importance of the valve independent, arrested hydrocephalus (author's transl)].

Between 1964 and 1974 193 infants up to the age of 2 years were treated for progressive hydrocephalus by means of a ventriculo-atrial shunt. Long term follow-up studies were possible on 148 children. Among these 94 have functioning and 54 non-functioning valves. The criteria for the non-function were based on either plain X-rays of the skull and thorax (disconnection of the catheters, distal end of the cardiac catheter above D 2), direct punctures of the antichamber and contrast medium studies of the diversional system. 35 children with non-functioning valves were normal in their mental and motor development, 9 were retarded according to their primary brain damage, 10 patients showed signs of chronic increased intracranial pressure. These results suggest, that about one fourth of the valve treated patients develop a state of valve independency.

Cerebrospinal Fluid Shunts↗