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Biomedical subjects

G Seibert

Publications and source records attributed to G Seibert.

62 records · Page 4Linked to original sources
PubMed1976

Spacelab and its utilization for biomedical experiments.

The types of investigations possible in the orbital laboratory Spacelab are considered. A summary of services available to the Spacelab user is given, in which the load carrying capacity and the characteristics of the main subsystems (e.g. thermal control, environmental control, electrical power and energy as well as data management) are briefly described. Life science investigations may be undertaken for two reasons: firstly, to ensure safety and efficiency, and, secondly, for their scientific interest relating to effects of weightlessness or cosmic radiation. Safety of the crew and their genetic cells in relation to cosmic radiation is considered vital; essential knowledge is also required about the performance of the vestibular balancing mechanism and the related problem of "stomach awareness". The effect of zero-gravity on the cardiovascular system is studied, and the effect of circulatory changes in the brain, possible psychological stress and effects on exercise tolerance measured. Due to their rapid reproduction, important information may be gained from micro-organisms in respect of mutation rates when exposed to radiation. Plants depend, to some extent, on gravity in germination and growth. Of interest here is the relative importance of gravitational and photonic influences.

Adaptation, Physiological↗
PubMed1975

[The influence of high-frequency hyperthermia on Ehrlich-ascites carcinoma in the mouse].

On 988 NMRI-mice the influence of a single high-frequency hyperthermia of differing intensity in the decimeter-wave field was investigated regarding the course of the Ehrlich's-ascites carcinoma. The application of high frequency (461,04 MHz) was made with an electrode on an induction field of 3,8 cm diameter, and covers the whole peritoneal cavity. No significant prolongation of the survival time was achieved, neither by increasing the intensity up to the final rectal temperature of 40 degrees-43 degrees C, nor by selecting different therapeutic periods during the growth of the tumor (1, 3, 6, and 10 days after inoculation). In contrast to local tumors which can be cured solely by high frequency treatment in the chosen model of a generalized tumor (in which the tumor tissue cannot be separated), no significant therapeutic effect can be reached by sole thermotherapy--not even with the risk of extremous therapy-induced complication rates. An interesting field for research seems to exist as to what extent tumor proliferation kinetics can be influenced by high frequency.

Animals↗
PubMedDate not supplied

The Antibacterial activity in vitro and beta-lactamase stability of the new cephalosporin HR 810 in comparison with five other cephalosporins and two aminoglycosides.

The antibacterial activity of the cephalosporin antibiotic HR 810 was evaluated in comparison with cefoperazone, cefotaxime, ceftazidime, ceftriaxone, latamoxef, gentamicin and amikacin against 1500 clinical isolates. HR 810 is the antibiotic with the broadest antimicrobial spectrum. It is also highly active against isolates of the genera Pseudomonas, Enterobacter, Staphylococcus and enterococci. HR 810 is very stable against hydrolysis by plasmid-coded and chromosomally coded beta-lactamases.

Acinetobacter↗
PubMedDate not supplied

Chemotherapeutic properties of the new cephalosporin antibiotic HR810 in laboratory animals.

The chemotherapeutic properties of the new aminothiazolyl cephalosporin HR810 were investigated in experimental animals. Unlike other cephalosporins of the third generation, HR810 had good activity against Staphylococcus aureus as well as some activity against enterococci. In murine protection tests with these strains, it was clearly superior to ceftazidime, cefotaxime, ceftriaxone, cefoperazone and latamoxef. The compounds most effective in protecting mice from infections caused by Enterobacteriaceae were HR810 and ceftriaxone followed by ceftazidime, latamoxef and cefotaxime; cefoperazone was less active. HR810 was less active against Pseudomonas aeruginosa than ceftazidime but was considerably more effective than the other cephalosporins tested. HR810 also proved effective against localised infections such as thigh lesions, as well as against meningo-encephalitis in mice and pyelonephritis in rats. These results in laboratory animals make HR810 a promising candidate for clinical studies.

Animals↗
PubMedDate not supplied

Fractionated precipitation of acid macropolyanions by dialysis, a simple method for the estimation of DNA in complex biological samples.

After efficient extraction by para-aminosalicylate, chopping, grinding and eventual sonication, the macropolyanions are transformed into their cetyltrimethylammonium salts. These have differing solubilities, strongly depending on ionic strength. The cationic detergent-macropolyanionic salts are solubilized by high salt concentration. Salt is then dialysed out, rendering the polyanions highly insoluble in a sequential fashion. The insolubilized components are determined quantitatively by monitoring turbidity, which in case of DNA is strictly proportionate to its concentration. This relation is not affected by other components. This makes DNA determination possible even in crude aqueous extracts. The method has been applied to different objects, such as bacteria, plants, animals, soil and activated sludge. The method may prove to be especially useful in research of environmental poisons e.g. in rivers, lakes or clarifiers.

Animals↗