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Biomedical subjects

M Herrmann

Publications and source records attributed to M Herrmann.

At least 253 records · Page 14Linked to original sources
PubMed1983

[Artificial blood. Experimental studies on fluorocarbons as chemical blood substitutes].

Fluorocarbonates are organic compounds capable of carrying oxygen and surrendering it to tissues by means of biological sound modalities. Experimentation of an emulsion consisting of perfluorotripropylamine and perfluorodecaline (Fluosol DA 20%) as a blood substitute is reported. Acute (Ht less than 1%) and chronic morphological (Ht = 15%) studies were performed on rats, and a semi-acute biochemical and morphological protocol (Ht = 21%) was experimented in pigs. The first signs of altered cerebral electrical activity occurred at Ht = 2% in the acute experiments, and death due to respiratory arrest took pace at Ht = 0.5%. In the semiacute and chronic experiments, widespread infiltration of fluorocarbonic micelles was noted on histological and electron microscope lung and liver preparations.

Acid-Base Equilibrium↗
PubMed1983

Proteins and glycoproteins of monkey and human platelets. Comparison by high resolution two-dimensional gel electrophoresis.

1. The protein and glycoprotein composition of the blood platelets of six primate species have been compared by high resolution two-dimensional polyacrylamide gel electrophoresis. 2. Only minor differences have been observed in the protein patterns of all six species. 3. The glycopeptide patterns of the monkey platelets five species) were rather uniform, but clearly different from the human pattern.

Animals↗
PubMed1982

Quinidine-digoxin interaction: evidence for involvement of an extrarenal mechanism.

The influence of quinidine 750mg per day for one week on serum digoxin concentration (SDC) was evaluated in digitalized anuric patients on chronic haemodialysis. During quinidine administration the SDC increased markedly, from 0.84 +/- 0.37 to 1.58 +/- 0.72 ng/ml (p less than 0.01), a comparable effect ot that reported previously in patients with normal renal function. Neither in vitro nor in vivo did quinidine alter the serum protein binding of digoxin. The increase in SDC in anuric patients indicates a decrease in the extrarenal clearance of digoxin, which means that mechanisms other than of renal origin are also involved in the interaction of quinidine and digoxin. There was great interindividual variability in the extent of the quinidine-induced rise in SDC. Regardless of the state of renal function, careful monitoring of digitalized patients seems mandatory once quinidine treatment is initiated.

Anuria↗
PubMed1982

[Effects of a partial exchange transfusion with Fluosol DA 20% on healthy pigs].

In 9 animals 500 ml of blood was replaced with 500 ml of Fluosol DA 20%. An average of 19.2 ml per kg body weight of emulsion, i.e. 3.883 gm per kg body weight of fluorocarbons was given. On the eighth day following exchange transfusion the animals were killed and tissue samples taken from liver and lung for electron microscopy and chemical analysis. Biochemical parameters were measured in central venous blood prior to transfusion and on the 2nd, 3rd, 6th and 8th days. One animal died on the sixth day of study, hence only the results obtained from the remaining 8 animals were analysed. On removing the lungs a marked firmness of consistency and failure to collapse was noted. Electron microscopy revealed numerous phagocytic cells packed with foam-like substance, partly occluding the pulmonary capillaries. On chemical analysis a residue of 23.95 mg fluorocarbon per gm of lung tissue was found. Acid-base analysis of central venous blood showed a compensated respiratory acidosis on the 6th and 8th day. The hepatic reticulo-endothelial system was found to be laden with numerous vacuoles, to such a degree that the sinusoids were all practically fully occluded. Neither cell necrosis nor inflammatory reactions were observed.

Acid-Base Equilibrium↗
PubMed1981

[Interrelationships between pars intermedia and posterior pituitary with regard to corticotrophic and thyrotrophic partial function in rats].

Functional interrelationships between the pars intermedia and posterior pituitary were proved under different experimental conditions. After stimulation of the thyrotropical axis of rats by an acute intraperitoneal application of 50 microgram TRH/rat the nuclear sizes of the thyroid follicular and the anterior pituitary thyrotropical cells increased according to a monophasic time curve with maximal amplitude at the time of 30 minutes. Interestingly, the nuclear sizes of the posterior pituitary cells were also enhanced. Under the same experimental conditions the nuclear areas of the cells of the external layer of the adrenal zona fasciculata decreased as did the nuclei of the pars intermedia cells (without regard to the cell type or localization of the cells in the intermediate lobe). Stimulation of the adrenocorticotropical axis by an acute injection of 0.2 ml isotonic saline solution/rat was followed by a time-dependent increase of nuclear sizes of the fasciculata cells and pars intermedia, whereas the nuclear volumes of the thyroid follicular cells, the anterior pituitary thyrotropical cells and the posterior pituitary cells decreased. Thus the functional state of the pars intermedia was in accordance with that of the adrenal cortex. Also the posterior pituitary cells responded to stimuli applied to the thyrotropical axis at the same degree as the thyrotropic organs themselves. Between the nuclear sizes of the pars intermedia and posterior pituitary we established the same inverse functional relationships as between the adrenal cortex and the thyroid gland.

Adrenal Cortex↗
PubMed1980

[Morphology of the pig liver after Fluosol infusion].

About 500 ml of blood of young pigs weighing 20...25 mg were replaced by artificial blood substitute "Fluosol-DA 20%". Eight days after exchange the animals were sacrificed and the liver was fixed for electron microscopic investigation. The morphological studies showed Fluosol-droplets in the cytoplasma of parenchymal cells near the bile canaliculi and in the sinusoidal lining cells. Most Fluosol-droplets were found in the endothelial and Kupffer cells which both seemed to be completely filled. The ballooning of these cells often resulted in a partial occlusion of the sinusoids. The sinusoidal lining cells were saturated by Fluosol droplets to such an extent that they seemed to be unable to phagocytize further.

Animals↗
PubMed1980

[Oscillation in the energy metabolism of the insect host and symbiont. II. Analysis of possible endogenous rhythms in both systems].

The insect group which includes cicadas harbours intracellular bacterial symbionts (endocytobionts) which are passed on from generation to generation in the form of a symbiont ball inserted between the egg membrane and the rear pole of the egg cell. Bioluminiescence methods can be used to measure the oscillations in ATP, ADP and AMP levels in egg systems which have been separated into a host and a symbiont egg part (Euscelidius variegatus), and which are exposed to constant light at 26 degrees C, 70% relative humidity and 7,000 lux. Comparison of the energy charge curves of host and symbiont egg parts suggests an antagonistic relationship at high frequencies, and a synchronous relationship at low frequencies (length of period 23--27 h). These relationship can, however, only be reproduced as phase-shifted oscillation patterns. The most appearing interpretation of this data is that the oscillation pattern represent a basic circadian rhythm, and that the phase-shift is produced by an underlying endogenous yearly rhythm. This, however, indicates a regulative coupling between the energy metabolism of the host egg and that of the prokaryotic egg-symbiont. Regulated correlations in the energy charge were also observed between the mitochondria and the cytoplasms/nucleus system. It follows that endocytobiosis can serve as an experimental model for the biochemical analysis of eucyte systems.

Adenine Nucleotides↗
PubMed1979

About the relationship between adrenal cortex and thyroid gland of rats (shift-effect).

In the present paper the inverse quantitative relationships between the thyrotropical system and the adrenocorticotropical system should be demonstrated under different acute experimental conditions by caryometric investigations. In stimulating the adrenal cortex system by a single injection of 0.2 ml saline solution (0.9%)/rat the nuclear sizes of the thyroid follicular cells decreased timedependend whereas the nuclear parameters of adrenal cortex fasciculata cells increased. In inhibiting the adrenal cortex system and stimulating the thyrotropical system by a single injection of 50 micrograms TRH/rat the thyroid nuclear values increased timedependend biphasically and the adrenal cortex parameters decreased correspondingly. The inverse relationships of the histometric parameters of both endocrine organs proved to be highly significant (p less than or equal to 0.001). The mathematical relations could be expressed by the straight line y = 63.76 - 1.05 x.

Adrenal Cortex↗
PubMed1979

[Oscillations in the energy metabolism of the host and symbiont of a cicada. I. Analysis of possible metabolic and physiologic correlations of both systems].

The insect group which includes cicadas harbours intracellular bacterial symbionts which are passed on from generation to generation in the form of a 'symbiont ball' inserted between the egg membrane and the rear pole of the egg cell. Bioluminiscence methods can be used to measure the oscillations in ATP, ADP and AMP levels in egg systems which have been separated into a host and a symbiont part (Euscelidius variegatus, Euscelis incisus), and which are exposed to constant light or light-dark variations under otherwise constant conditions (26 degrees C, 70% relative humidity, 7000 lux). The energy charge can be calculated from the ATP, ADP and AMP concentrations. Comparisons of such curves suggest an 'antagonistic' relationship in the energy metabolism of the host and symbiont parts of the egg. The minima of oscilaltions in the host's energy metabolism generally occur at the same time as the maxima in the endocytobionts energy metabolism. Antagonistic correlations between the nucleus/cytoplasm and mitochondria/plastids were also observed in the eucyte system. Analogies between the two systems can be explained satisfactorily by the endosymbiont theory of the origin of eucytes. It follows that insect endocytobioses can serve as an experimental model for the biochemical analysis of the eucyte system.

Adenine Nucleotides↗