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Biomedical subjects

U N Riede

Publications and source records attributed to U N Riede.

At least 91 records · Page 5Linked to original sources
PubMed1978

Selective induction of melanomas in gerbils (Meriones unguiculatus) following postnatal administration of N-ethyl-N-nitrosourea.

Following a single ip injection (50 mg/kg) of N-ethyl-N-nitrosourea (ENU) on postnatal day 7 or 20, 9 of 21 gerbils (43%) developed a total of 15 cutaneous melanomas. The mean survival time of tumor-bearing animals was 909 +/- 212 (SD) days. Neoplasms were preferentially located at sites with little hair and with high content of pigment cells (feet, ears, tail, or snout). Histologic studies on newborn gerbils indicated that ENU-induced malignant transformation occurred in differentiated melanocytes rather than in precursor cells of the neural crest.

Animals↗
PubMed1977

[A comparative ultrastructural-morphometric study of the cochlear spiral ganglion in rats and guinea pigs (author's transl)].

The cochlear spiral ganglion of rats consists of 61.8% granular ganglion cells, 22.4% satellite cells and Schwann cells, 9.3% extracellular space, 4.8% myelinated nerve fibers and 1.4% filamentous ganglion cells. The granular ganglion cells consist of 76% cytoplasmic components and 24% nuclei. Their cytoplasm contains 66.3% hyaloplasm, 11.4% mitochondria, 11% free ribosomes, 7.8% rough endoplasmic reticulum, 2.7% Golgi apparatus and 0.8% lysosomes. Comparing with morphometric data in guinea pigs, granular spiral ganglion cells in rats show some species dependent differences in their quantitative cytoarchitecture. They don't differ in their principal architectural pattern, especially in regard to the metabolism for energy and cell performance. The spiral ganglion cells of rats in contrast to those of guinea pigs do not show viral particles. Since it is impossible to evaluate with certainty the influence of viruses on the metabolism of infected cells, in our opinon rats are more suitable experimental animals for morphometric investigations of spiral ganglions.

Animals↗
PubMed1977

[Influence of different fixation buffers on the quantitative cytoarchitecture of the cochlear spiral ganglion. A morphometric study (author's transl)].

The influence of two fixation buffers on the quantitative cytoarchitecture of the cochlear spiral ganglion in guinea pigs was evaluated morphometrically. After fixation with phosphate buffered 1.3% OsO4 granular spiral ganglion cells lost 45% of their average individual volume as compared to the volume after fixation with s-collidine buffered 1.3% OsO4. Using the two fixatives there was no significant difference of the volume proportion of cell nuclei, mitochondria, lysosomes and rough endoplasmic reticulum per unit volume cytoplasm of the granular spiral ganglion cells. The volume proportion of their ribosomes and their Golgi apparatus per unit volume cytoplasm increased 3.5fold after fixation with phosphate buffered OsO4. The volume density of the granular ganglion cells decreased by 30%, the volume density of the interganglionar space (= space between granular ganglion cells) showed an increase of 50% using phosphate buffer. Mostly the extracellular space was participating in this relative increase of the interganglionar space. As a result fixation of the spiral ganglion for morphometric studies should be performed using s-collidine buffered OsO4. The morphometric findings underline the presumption of semicompact myelin being a fixation artefact.

Animals↗
PubMed1977

[Ultrastructural morphometric analysis of the spiral ganglion in guinea pigs (author's transl)].

This is the first morphometric analysis of the cochlear spiral ganglion. Therefore the ganglion was subdivided in precisely defined compartments. We found that the normal, untreated spiral ganglion in guinea pigs contains 58% ganglion cells of the granular type, 26% satellite cells and Schwann cells, 8.6% extracellular space, 6.4% myelinated nerve fibers and 1% ganglion cells of the filamentous type. The granular ganglion cell consists in 83% out of cytoplasm and in 17% out of nuclei. The cytoplasm is containing 13% ribosomes, 12% mitochondria, 10% RER, 2.1% Golgi apparatus, 1.3% lysosomes. Based on these quantitative datas we expect to detect alterations of the normal structure earlier and more precisely under pathophysiological conditions as before.

Animals↗
PubMed1977

A unifying concept for the role of matrix vesicles and lysosomes in the formal pathogenesis of diseases of connective tissues and blood vessels.

The cells of the connective tissues contain lysosomes with enzymes capable of degrading intercellular substances (collagen, elastin, proteoglycans) and release their enzymes in membrane-bound or in free form into their intercellular substance. In this way extracellularly located lysosomes (= matrix lysosomes) can be detected by morphological and enzymatic means as well as by their metal concentrating property. This function of such matrix-lysosomes is in connection with the two step-degradation of the connective tissue and is thought to be the main part for the fibrocytic fibrolysis, chondrocytic chondrolysis, osteocytic osteolysis and myocytic mediolyses in the vessel wall. The cells of the mesenchymal tissues thus control the turnover and transformation of their own ground substance. Inflammatory and immunologic processes are suggested to be superimposed on this lysosomal action. If the lysosomal enzyme system in the connective tissues and the vessel wall gets out of control, the consequences can be dangerous as e.g. in case of relapsing polychondritis and arterial aneurysms. In this enzyme system proteolytic activators as well as proteolytic decomposable inhibitors are present. The corresponding proteolytic processes are of lysosomal nature and are subordinated to other regulatory mechanisms.

Aneurysm↗
PubMed1977

Effects of cellophane tape stripping of mouse skin on epidermal growth regulators (chalones).

Variations in epidermal chalones after a single surface application of methylcholanthrene and croton oil have been described in previous papers. This paper reports a study of the effect of adhesive tape stripping of the skin on epidermal growth regulators (G1 and G2 chalones). Pieces of adhesive tape were applied 6 times to the same area of skin in groups of mice. The short-term effects of tape stripping on epidermal DNA synthesis and on mitotic rate were studied at different intervals after stripping. Other groups of mice were killed at similar time intervals after stripping, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibitions were interpreted as an expression of the concentration of G1 or G2 chalone in the skin extracts. The first experiment confirmed that cellophane tape stripping gives rise to a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of labelling index being found on days 2 and 6, and the two maxima of mitotic rate on days 1-2 and 7. The concentrations of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. Here there was initially a depression of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short reaction of the basel cells to the stripping trauma. It is concluded that adhesive tape stripping removes the differentiating cells and injures some basel cells, simultaneously altering the content of G1 and G2 chalones. The resulting increase in the rates of DNA synthesis and mitosis lasts only until the number of cells is high enough to produce growth-regulating substances (chalones) again. This theory may explain the changes observed. Since similar reactions are seen after both carcinogenic and co-carcinogenic chemical injury of the epidermis, the reaction pattern seems to be a general response to cell injury or cell removal.

Animals↗
PubMed1977

[Oncorna-like virus particles in the cochlear spiral ganglion of guinea pigs (author's transl)].

INTRODUCTION: Virus particles in spiral ganglion cells of the guinea pig have been grouped with herpes viruses. The purpose of this study was to evaluate this classification of the viruses and their influence on cell morphology. MATERIAL AND METHODS: 20 healthy, adult guinea pigs from different breeds were studied. The spiral ganglion was serially sectioned and examined electron micoscopically. RESULTS AND DISCUSSION: All examined spiral ganglions of several guinea pig populations from different breeds showed intracytoplasmic viruses in some granular spiral ganglion cells. According to their localization and morphology we classify these viruses with the oncorna virus group. This is not in agreement with the classification of other authors. Apparently there is a world-wide latent viral infection in guinea pigs. The accumulation of lysosomal-like vacuoles in vicinity to the viruses indicates an increased local lysosomal activity of the infected ganglion cells. Considering the otherwise normal ultrastructure of the infected cells an additional influence of these viruses on the intracellular metabolism can neither be demonstrated nor denied.

Animals↗
PubMed1977

[The fructose induces "glycogenosis". III. Histochemical and morphometrical studies of glycogen metabolism in mouse liver after fructose overload (author's transl)].

INTRODUCTION: After feeding fructose for 7 days rat liver cells show an accumulation of glycogen, a high activity of glucose-6-phosphatase combined with a SER- and RER-reduction. This result was reviewed by mouse liver cells using histochemical and morphometrical methods. MATERIAL AND METHODS: 60% fructose in drinking water was given mice as only nutritional source. Controls had free access to Altromin-R-standard diet and drinking water. Glycogen and glycogen metabolizing enzymes are demonstrated in the course of an 1-14 days fructose diet. After a 7 days diet liver tissue was analysed morphometrically. RESULTS AND DISCUSSION: Feeding of fructose leads to a high glycogen content, combined with a high activity of glycogen-phosphorylase and glucose-6-phosphatase in the liver parenchyma of mouse. Glycogen-synthetase activity falls to a low level. The SER and RER and the peroxisomes are reduced. The single volume of the hepatic nucleus is decreased and the hepatocellular chondrioma is transformed in a smaller number of larger mitochondria. Compared with the rate the analysed organelles and enzymes of mouse liver show only slight quantitative differences. The increase of glucose-6-phosphatase and simultaneous reduction of endoplasmic reticulum-membranes is illustrated by the dynamic structure of endoplasmic reticulum-membranes, which adapt to metabolic changes. The variable turnover of different parts of endoplasmic reticulum-membranes seems to be very important.

Animals↗
PubMed1977

[Ultrastructural study on formal pathogenesis of experimentally induced rhabdomyosarcomas (author's transl)].

UNLABELLED: During oncogenesis the rhabdomyosarcomas pass different stages of differentiation. In experimentally induced rhabdomyosarcomas the chronological sequence of cytoplasmatic changes can be analysed. MATERIAL AND METHODS: 10 mg 9,10-dimethyl-1,2-benz-anthracene were injected subcutaneously or intramuscularly in the hind-paw of Wistar rats with 100 gms weight. 30, 60, 105, and 150 days later the animals were killed and specimens withdrawn. The soft-tissue was prepared for light- and electron-microscopy. RESULTS: In the soft-tissue tumors, experimentally produced with DMBA, 4 different cell types can be observed, which--depending on exposition time--dominate in the histological picture: (1) The myofibrillar cells. These cells are similar to rhabdomyocytes and contain numerous cytoplasmatic fibrillae with sarcomere-like structure. (2) The myofilamentous cells. These cells contain the fibrillar structure, but without sarcomere-like arrangement. (3) The undifferentiated sarcoma cells. These cells show a pathologically changed ergastoplasm and chondrioma. (4) The matured fibrosarcoma cells are nearly similar to fibrocytes. Under the cytoplasmatic changes especially the hyperplasia of the chondrioma can be observed, in which dystrophic megamitochondriae are found. These possibly reflect the abnormal glycolysis in cancer tissue. Also mitochondrial antibodies are discussed at the form pathogenesis of this change in organelles. Regarding the change of the endoplasmatic reticulu, the annulatae lamellae can be noticed which are typical for tumor cells. Furthermore megacisterns are found, in which protein-containing material is condensed as a consequence of a disturbed synthesis and secretion.

Animals↗
PubMed1976

Effects of croton oil on epidermal growth regulators (chalones).

Variations in epidermal chalones after a single surface application of methylcholanthrene have been described in previous papers. This paper reports a study of the effect of croton oil on epidermal growth regulators (G1 and G2 chalones). Hairless mice received a single topical application of 0.2 ml 0.25% acetone solution of croton oil. Control mice received only acetone. The short-term effect of croton oil on epidermal DNA synthesis and mitotic rate was studied. Other groups of croton oil-treated and acetone-treated mice were then killed at similar time intervals, and the treated area of skin was homogenized and extracted with water. The inhibitory effect of these extracts on normal epidermal DNA synthesis and mitotic rate was assayed in normal hairless mice. The resulting inhibition was interpreted as an expression of the concentration of G1 and G2 chalones, respectively, in the skin extracts. The first experiment confirmed that a single croton oil application provokes a short block in epidermal mitotic activity and probably also in DNA synthesis. This was followed by bimodal peaks of increased activity, the two maxima of mitotic rate on days 2 and 7. The concentration of the two chalones in the skins of treated animals varied in inverse proportion to the alterations in the DNA synthesis and the mitotic rate, with one exception. There was here initially a depression both of the mitotic rate and a low concentration of G2 chalone. This was interpreted as a short, initial direct effect of croton oil on the G2 chalone present at the time of application. It is concluded that croton oil application injures and kills epidermal cells, with subsequent alterations in the content of G1 and G2 chalones. This theory may explain the changes observed. The effects of croton oil on the amount of G1 and G2 chalones in the skin are probably related to the direct, toxic, cell-killing effect of croton oil, and not to its specific cancer promoting potency.

Animals↗
PubMed1976

[Influence of calcitonin on the quantitative cytoarchitecture of juvenile rats, a morphometric study on rat hepatocytes (author's transl)].

UNLABELLED: 1. INTRODUCTION: Using ultrastructural-morphometric analysis of liver parenchymal cells, following long term calcitonin administration, the suggestion that calcitonin influences intermediate as well as calcium metabolism has been strengthened. 2. MATERIALS AND METHODS: The experiments were performed with 10 young male Wiatar rats. 5 animals received salmon calcitonin intraperitoneally every day for 6 weeks, 5 untreated animals served as controls. All animals had free access to water and Altromin-R-standard diet. The morphometric investigations were carried out by a method analogous to that of Weibel (1969). 3. RESULTS AND DISCUSSION: By comparison with controls smaller cells and nuclei were seen. Following calcitonin treatment the mitochondrial content of liver parenchymal cells was markedly reduced. On the other hand the surface of cristae was doubled. A proportional membrane and enzyme production in the sense of an adaption, or a disproportional membrane and enzyme synthesis as a misadaption is discussed as the pathogenetic mechanism. Furthermore the number as well as the volume of peroxisome, and lysosomes was reduced. Total liver calcium decreased, whereas serum calcium concentration increased slightly. This can be explained through raised renal reabsorption as a compensatory effect of parathyroid hormone.

Animals↗
PubMed1976

[The fructose induced "glycogenosis". II. Histochemical studies of glycogen metabolism in rat liver after fructose overload and similar diets (author's transl)].

INTRODUCTION: Feeding of fructose for 7 days has been morphometrically shown to induce a SER-reduction and an accumulation of glycogen in rat liver cells. This hypothetical model "glycogenosis" is investigated with histochemical methods. MATERIAL AND METHODS: Rats are given a solution of 60% fructose in water as only nutritional source. Controls are given a solution of 60% glucose in water, an isocaloric Altromin-R-standard diet and an Altromin-R-standard diet ad libitum. Reversion of fructose induced metabolic changes is investigated by a 7 days fructose diet followed by an 1-4 days Altromin-R-standard diet ad libitum. Glycogen and glycogen metabolizing enzymes are demonstrated after a 7 days diet and in the course of an 1-7 days fructose diet. RESULTS AND DISCUSSION: Feeding of fructose leads to a high glycogen content, combined with a high activity of glycogen-phosphorylase and glucose-6-phosphatase in the liver parenchyma. Glycogen-synthetase activity increases during the first 4 days and then it drops to a low level. A pathological alteration of liver cell metabolism seems to be improbable, for all fructose induced changes are reversibel after 2 days of Altromin-R-standard diet. Glucose-6-phosphatase, as a marker-enzyme of the smooth endoplasmatic reticulum, is discussed to become activated by disruption of SER membranes due to fructose.

Acid Phosphatase↗