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Biomedical subjects

H Ueberberg

Publications and source records attributed to H Ueberberg.

At least 37 records · Page 2Linked to original sources
PubMed1980

[Potassium hydrogen phosphate induced nephropathy in the dog. II. Glomerular alterations (author's transl)].

A disseminated atrophy of the proximal tubule accompanies K2HPO4-induced nephropathy in dogs. These pathologic processes cause glomerular changes that pass through different inflammatory stages and terminate in glomerular sclerosis. Experimental animals, design of the experiment and methods have been described [15]. During the 14-week study we determined the amount of urine (24 hours), protein (mg/dl), protein excretion (mg protein/24 hr) and the macro- and microprotein fraction in the urine by SDS-polyacrylamide gel electrophoresis. Clinical examinations were at 15, 66, and 85 days. Beagle dogs treated with 0.8 g K2HPO4/kg body weight developed significant glomerular selective and unselective protienuria. During the experiment the macroproteins in the urine decreased markedly, and at the last examination (day 85) glomerular proteinuria was no longer detectable by electrophoresis. Morphologically, there were only slight glomerular changes in the biopsy material taken at four weeks. Widespread lesions at 14 and 38 weeks were dilatation of Bowman's space, thickening of the basement membrane, increase in mesangial matrix, interposition of non-argentophilic mesangial matrix into the glomerular basement membrane, protein deposits in the mesangium and parietal basement membrane, formation of crescents, shrinkage of the glomeruli with collapse of glomerular tufts, and finally glomerular sclerosis. The parietal epithelial cells contained cytoplasmic areas that were free of organelles and contained microfilamentous and fine-granular material. These areas were close to the capsular basement membrane. Bundles of filaments within parietal epithelial cells had contact with the basement membrane, thus resembling hemidesmosomes. The sequelae of tubular atrophy are retention of glomerular filtrate and dilatation of Bowman's space, followed by compression and shrinkage of the glomerular tufts, and inflammatory processes within the glomerulus. The latter may be characterized as mesangio-sclerosing, mesangio-proliferative, membrano-proliferative, and extra-capillary glomerulonephritis. The decrease of urinary protein excretion towards the end of the experiment may be related to intratubular lysosomal digestion of cellular and amorphous components.

Animals↗
PubMed1979

[Experimental investigations of the content of glycogen in the adrenal gland of the rat after application of dexamethasone, ACTH and a combination of both (author's transl)].

The influence of dexamethasone, ACTH and the combination of both on the glycogen content of the rat adrenal gland was studied. Dexamethasone induces a transient increase of the adrenal glycogen content in a time and dose-dependent manner. The application of ACTH has no effect on the glycogen content. Surprisingly, the increase of the glycogen content induced by dexamethasone is completely blocked by the simultaneous application of ACTH.

Adrenal Glands↗
PubMed1979

The spontaneous rate of tumours in the laboratory rat: strain Chbb: THOM (SPF).

The aim of this investigation was to examine the time relationship of the rate of development of spontaneous tumours in the rat, strain CHBB: THOM (SPF). The rats were divided into 6 groups, each of which consisted of 100 male and 100 female animals. The first group was killed at the age of 15 months, and the last group when aged 2 1/2 years. Thus the time interval between sacrificing the individual groups was 3 months. Spontaneous tumours seldom appear in animals up to 15 months of age except in the testes, pituitary and mammary glands. Apart from these organs tumours develop mainly in the lung, lymph nodes, thymus, adrenal cortex, thyroid, ovary, uterus, skin and in the brain. Benign tumours predominate. Malignant tumours with metastases are rare. The incidence of tumour formation increases after the age 21 months. Statistically significant increases can only be shown in a few organs.

Animals↗
PubMed1978

[Electronmicroscopic findings in a malignant hepatoma after oral contraceptives (author's transl)].

In this paper we report the electronmicroscopic findings in a hepatocellular carcinoma of a 24 years old woman after taking oral contraceptives. We saw alterations of the nucleus (finger-like or finger-formed nuclei, nuclear invaginations and intranuclear vesicular membranbodies), changes of the mitochondries (number, polymorphy and osmiophil bodies) as well as changes of lysosomes (myelinshaped residualbodies). The observed and described changes are not specific for malignant tumors of the liver.

Adult↗
PubMed1978

[New results on ageing of connective tissue (author's transl)].

Some new results on ageing of connective tissue are demonstrated, regarding not only mesenchymal, but also parenchymal organs of human and rat (both sexes). These results show that ageing of connective tissue is more a dynamic process (with measurable metabolic parameters of the several connective tissue cells and their products) than a passive or so-called degenerative connective tissue process. The bradytrophy concept of connective tissue cannot be accepted any longer. Then connective tissue cells can produce metabolic rates of the same level like parenchymal cells. The different organs possess partly common basic processes partly differences in connective tissue ageing, dependent on the composition and patterns of proteoglycans resp. of GAG and collagen types, furthermore dependent on localisation, structure and function. The results on ageing of connective tissue are useful for better understanding of ageing processes of parenchymal organs. Then their ageing is influenced essentially by the ageing of the own connective tissues. The turnover, more than the number of mesenchymal and parenchymal cells, decreases with ageing. More old than young cells seem to exist in old tissues and organs. The performance of ageing connective tissue cells can be constant or increase or decrease. Many mesenchymal and parenchymal organs develop a so-called "ageing-fibrosis".

Aged↗
PubMed1978

Ultrastructural investigations of the formation of Candida albicans germ tubes and septa.

Germ tubes, blastospores and pseudomycelia of Candida albicans were studied under the electron microscope. Both germ tube and blastospore formation begin with comparable changes in the cell wall of the mother cell. The major part of the germ tube wall consists of the fourth of the five layers forming the C. albicans cell wall. Germ tubes are precursors of mycelia which can ramify. Septa and septal pores can be demonstrated in later phases. Pseudomycelia can be clearly discerned by means of transmission electron microscopy.

Candida albicans↗
PubMed1978

[The predictive value for man of toxicological findings in experimental animals (author's transl)].

The extrapolation of toxicological findings in experimental animals to man is an important and difficult problem. However, experiments on several animal species form the basis for deciding whether or not a new substance should be given to or tested on humans. Compounds which even in low doses lead to dose-dependent organic damage should obviously not be developed any further. There are, however, cases in which no firm conclusion can be reached by the toxicologist on the grounds of the results of animal experiments alone, as to whether or not the substance should be used in man. In such cases close collaboration is necessitated between the pharmacologist, toxicologist, biochemist and physician. Their aim is to decide if preliminary trials may or may not be carried out in human subjects. If the answer is in the affirmative, early administration to man should follow, as there is no clear-cup solution to the question of extrapolating findings in animal experiments to test subjects. Medical progress relies on research which, in the end, has to be supported by experiments on humans.

Animals↗
PubMed1977

Estrous cycle-controlled cell proliferation in the adrenal cortex of female rats.

In a total of 120 rats the number of 3H-Tdr-labelled nuclei of the adrenocortex was counted during various phases of the estrous cycle. In two separate experiments cyclic variations in the number of DNA synthesizing cells were found. The labelling index of the zona glomerulosa showed a significant maximum in proestrus whereas in zona fasciculata a minimum was revealed in estrus. In the glomerulosa the maximum of labelled cells was followed by a mitotic peak in estrus. Due to very low numbers of labelled cells no rhythm was found in the reticularis. The possible endocrine regulations of this endogenous rhythm of adrenocortical cell replication are discussed.

Adrenal Cortex↗
PubMed1977

Experimental allergic encephalomyelitis. Water, sodium and potassium concentration in spinal cord and hemispheres and their changes after dexamethasone treatment.

Water content, Na+, K+ and Cl- concentration were measured in rats with experimentally produced allergic encephalomyelitis. Increase of water content by 10%, accumulation of Na+ by 13%, of Cl- by 20% and decrease of K+ by 10% was observed in the spinal cord, but no substantial changes were found in the brain tissue. The hydration of spinal cord is accompanied by perivascular infiltrates. Dexamethasone, administered from day 5, after injecting sensitising encephalitogenic basic protein, effects normal levels of water content and Na+, K+ and Cl- concentration.

Animals↗
PubMed1977

[Histological, electromicroscopical and histochemical studies on the central nervous system of rats after chronic treatment with imipramine (author's transl)].

Rat brains have been studied after treatment with oral doses of 50 mg imipramine/day for 3 and 6 months. 20 brains have been studied histologically, 3 brains electronmicroscopically, 6 brains histochemically as well as 34 controll brains. On the light microscopic level no pathologic changes of intravital origin have been revealed. The hyperchromatic changes of neurons were of the same character and degree and showed the same topic distribution in the experimental and in the control group. They should be regarded as postmortem artifacts. The pyramidal cells of hippocampus field h3, the Purkinje cells and the Golgi epithelial cells have been examined by electron microscopy. Besides a possible slight induction of lysosomes no alterations could be found. The histochemical studies (succinate dehydrogenase, ATPase, AMPase, acid phosphatase, PAS, methylgreenpyronin) revealed no differences between the experimental and the control group.

Acid Phosphatase↗
PubMed1976

[Animal studies on the tolerability of NAB 365 (clenbuterol) (author's transl)].

The findings of acute, subacute and chronic toxicity studies in rats and dogs with the new beta-mimetic agent 4-amino-alpha-[(tert.-butylamino)methyl]-3,5-dichlorobenzyl alcoholhydrochloride (NAB 365, clenbuterol) are reported. The longest period of investigation, with daily oral administration of the substance, was 18 months (rats) and 12 months (dogs). No abnormalities of any kind were found in the rat studies which could be attributed to the substance. The administration of clenbuterol to dogs produced microscopically small lesions in the myocardium which were not dose-dependent and which were localised entirely in the papillary muscle of the left ventricle. The reason for these lesions was that dogs react to the substance with severe tachycardia, as a consequence of a reduction in diastolic blood pressure produced even by very low oral doses. Oxygen deficiency occurs which affects particularly the papillary muscle. The response to hypoxia is better capillarisation. This causes an improvement in the oxygen supply, which in turn prevents the spread of existing necroses and the development of further lesions.

Administration, Oral↗