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Biomedical subjects

U Meyer

Publications and source records attributed to U Meyer.

At least 127 records · Page 7Linked to original sources
PubMed1992

Application of DNA techniques for identification using human dental pulp as a source of DNA.

Dental pulp tissue could be obtained in most cases from materials obtained under experimental conditions and from forensic casework (air accidents, burned and putrefied bodies). Teeth extracted during dental treatment (n = 30) were stored for 6 weeks and 4 years at room temperature. In addition teeth (n = 10) extracted from jaw fragments that had been stored for 15 years at room temperature, and teeth extracted post mortem from actual identification cases (n = 8) were investigated. Following extraction from dental pulp tissue the DNA concentration was measured by fluorometry. The amount of DNA obtained from the dental pulp tissue of a single tooth varied from 6 micrograms to 50 micrograms DNA. In most cases high molecular weight DNA was still present although the major portion consisted of degraded DNA. Genomic dot blot hybridization for sex determination using the biotinylated repetitive DNA probe pHY 2.1 was performed and sex was correctly classified in all cases using 50-100 ng target DNA. PCR typing of the HLA-DQ alpha and ApoB 3' VNTR systems from dental pulp tissue DNA was in agreement with the results obtained from blood, bloodstains, or lung tissue. In addition, Southern blot analysis of selected samples using the single locus VNTR probe pYNH24 was successfully performed. In all cases the DNA recovered from dental pulp was unsuitable for multilocus probe analysis.

Blotting, Southern↗
PubMed1992

[Quantitative analysis of lamina III pyramidal neurons in the parietal cortex of newborns].

The stage of neuronal development in the parietal (postcentral) cortex of human newborns was studied quantitatively in postmortem cases of different gestational (37th or 40th week) and postnatal age (2 hours or 3 weeks). In GOLGI-impregnated tissue obtained by autopsy, layer III pyramidal neurons were investigated. Comparatively, data were collected about dendrite parameters such as dendritic branching, length and spine density. The spine distribution (number and density) at the apical main dendrite, the apical tuft dendrites and in single basal dendritic fields as well, typically for the human layer III pyramidal neuron at the end of the gestational period, is described. Dendritic parameters from basal dendritic fields were compared in the three cases investigated (37th week with 2 hours or with 19 days of survival; 40th week of gestation with 2 days of survival). The large increase in spine number and density, especially in the second and higher orders of dendritic branching was obvious in the 19 days old infant brain. Special pathological aspects of the cases influencing the neuronal development are discussed. By means of a computerized method, quantitative data characterizing the human lamina III pyramidal neuron at the end of gestation are provided.

Cerebral Cortex↗
PubMed1991

The influence of long-term potentiation on the spatial relationship between astrocyte processes and potentiated synapses in the dentate gyrus neuropil of rat brain.

The influence of long-term potentiation (induced by repeated high-frequency stimulation of the perforant pathway) on the distribution pattern of astrocyte processes in the neuropil of the hippocampal dentate area containing the potentiated synapses was investigated by quantitative electronmicroscopy. It has been found that significant changes occurred in the ramification of astrocyte processes as well as in their topographic relation to synaptic complexes. When comparing the results obtained in LTP animals with active control or sham-operated animals, we found significant higher numerical density, but smaller volume, higher surface density and closer apposition of astrocyte processes to the synaptic clefts, boutons terminaux or spines in the potentiated synapses containing neuropil. The glial reaction to synaptic activation has been seen most pronounced 8 h after the LTP induction. The results are pointing to a participation of the glia cells in the maintenance of the LTP effect as well as to a metabolic coupling between synaptic transmission and glia function for equilibrating the homeostasis by clearing the extracellular space next to the transmission zones.

Animals↗
PubMed1990

[Benzalkonium chloride for vaginal contraception--the vaginal sponge].

From March 1986 to December 1987, a vaginal contraceptive, not yet commercially available in Germany, was studied in 56 women. The substance benzalconium chloride (BZC) was contained in vaginal sponges (n = 46), pessaries (n = 4) and cream (n = 6) at a dose rate of 1.18%. BZC is a surfactant of the ammonium series that ruptures the spermatozoal membrane. It is also a powerful bactericide and viricide. The advantages of the vaginal sponge (intercourse is safe immediately after insertion for the next 24 h and for multiple intercourses) made it pleasant for the women. The rate of transitory local side effects (16%) was acceptable. The vaginal contraception did not interfere with the sexual life. In 645 months of use 10 pregnancies occurred of which 9 happened with the sponge (PI 20.3). Its fixation before the cervix and the release of the spermicide is not reliable enough, so that we cannot recommend the sponge as a safe vaginal contraceptive.

Adult↗
PubMed1990

[Alpha tumor necrosis factor in the serum of patients with sarcoidosis, tuberculosis or bronchial cancer].

Tumor-necrosis-factor-alpha (TNF-alpha), which is secreted by cells of the macrophage/phagocytic system, interact in a variety of different ways with other cytokines and immunologically active substances. To investigate a possible role of TNF-alpha in granulomatous lung diseases and to determine whether sarcoidosis can be differentiated from tuberculosis on the basis of serum TNF-alpha levels, we studied sera from patients with sarcoidosis and active tuberculosis. Ninety-one percent of the patients with sarcoidosis and 83% of the patients with tuberculosis exhibited significantly elevated TNF-alpha levels as compered with controls. Since these levels remained elevated irrespective of clinical stage and even under therapy, it is believed that patients with sarcoidosis and tuberculosis experience continuous activation of TNF-2-alpha-producing cells of the myelomonocytic system. In addition, determination of serum TNF-alpha levels does not permit differentiation between sarcoidosis, tuberculosis or malignant disease.

Adult↗
PubMed1989

Prostaglandin-E2 9-ketoreductase from swine kidney. Production of antisera and application to development of a radioimmunoassay.

Prostaglandin-E2 9-ketoreductase (PGE2-9-KR, EC 1.1.1.189), the enzyme which catalyzes the reaction from prostaglandin E2 (PGE2) to prostaglandin F2 alpha (PGF2 alpha), was purified 580-fold from swine kidney. The molecular mass of the enzyme determined by SDS-gel electrophoresis was 33 kDa. Antiserum against the purified enzyme was raised in three rabbits. The antiserum was able to precipitate PGE2-9-KR from swine kidney and to crossreact with pGE2-9-KR from several reproductive organ tissues, such as rabbit ovary, rabbit corpus luteum, rabbit endometrium and human decidua vera. When swine kidney PGE2-9-KR was labelled with 125I and incubated with affinity-purified antiserum in the presence of increasing amounts of unlabelled enzyme, competitive binding of the unlabelled enzyme to the antibody was observed. A radioimmunoassay for the quantitation of the enzyme was developed. The standard curve was linear from 5 to 500 ng enzyme. The intra- and interassay coefficients of variation were 6.4 and 13.2%, respectively. The assay may be useful for the quantitation of PGE2-9-KR in several tissues under various physiological conditions.

Animals↗
PubMed1989

[Graft versus host reaction in an infant with DiGeorge syndrome].

An infant with complete DiGeorge syndrome was treated with blood transfusions and fresh frozen plasma because of severe septicemia and anemia. 9 weeks after the first transfusion and 2 weeks after administration of fresh frozen plasma he died of acute graft-versus-host disease. The blood products were routinely irradiated with 25 gray, the fresh frozen plasma was not irradiated. The diagnosis of GvHD was confirmed on autopsy. All cellular blood products including fresh frozen plasma which are used in the treatment of immuno-deficient patients have to be irradiated to avoid GvHD. Currently 50 gray are recommended.

Blood Transfusion↗
PubMed1988

Copper storage disease of the liver and chronic dietary copper intoxication in two further German infants mimicking Indian childhood cirrhosis.

A severe copper storage disease of the liver with micronodular cirrhosis resembling Indian childhood cirrhosis (ICC) was found in two siblings of a German family leading to death in one infant at the age of 13 months. The fatal outcome correlated with severe ballooning of hepatocytes and excessive formation of Mallory bodies. The copper content of the liver was 698 micrograms per gramme wet weight (control 5 micrograms) in the living patient and 2154 micrograms per gramme dry weight (controls 39, 54 micrograms) in the dead infant. In both cases copper was stored not only in hepatocytes but also to a high degree in mesenchymal cells. Chronic contamination of drinking water supplied from a well via copper pipes could be verified as the cause of copper intoxication, lending further support to ICC as an environmental, acquired disorder. Accumulation of exogenic copper already very early in infancy appears most important for the development of the disease, as both the parents and one child not exposed to copper intoxication during the first 9 months of its life are clinically healthy.

Chemical and Drug Induced Liver Injury↗
PubMed1988

Nutritional copper intoxication in three German infants with severe liver cell damage (features of Indian childhood cirrhosis).

Three of the four children of two unrelated German families fell ill in the first year of life with severe hepatopathy leading to death in two of the children so far, after a progressive clinical course and severe hepatic failure. Laboratory and morphological investigations revealed a high concentration of copper in the liver and to a lesser degree in the kidneys and other organs. The liver architecture was severely altered by micronodular cirrhosis with toxic liver cell damage similar to that found in Indian childhood cirrhosis. Epidemiologically, copper intoxication of the drinking water was verified. The drinking water was obtained from wells via copper pipes. The copper content of the drinking water went as high as 3400 micrograms/l in the two families while water taken directly from the well showed normal content but had lowered pH (6.2). Both parents were clinically healthy, as was an older son who had not been exposed to copper intoxication during the first nine months of his life. Therefore, copper intoxication during the perinatal period appears to be a prerequisite for manifestation of the disease.

Chemical and Drug Induced Liver Injury↗
PubMed1988

Scanning electron microscopical observations on telencephalon explants cultivated in vitro.

Telencephalon explants from 10 or 12 days old chicken embryos were cultivated 2 days in vitro and investigated by SEM. Already at that day, nerve fibres forming thick fasciculi were observed in the outgrowth region of the explant. Neuritic growth cones of the filiforme, or lamellipodiale type were demonstrated as well as button-like dendritic growth cones. The cell somata of bipolar or multipolar neuroblasts and pyramidal neurons could be distinguished from those of astrocytes. Some nerve fibres establish axosomatic or axodendritic contacts, basket-like arrangements of axon terminals around small neuroblasts were found.

Animals↗
PubMed1988

Long-lasting shifts in ribosomal systems of hippocampal granular neurons due to early postnatal hypoxia.

The present study was carried out in order to determine pathogenetic mechanisms of the human minimal brain dysfunction syndrome caused by perinatal hypoxic states. In our animal model newborn rats were exposed to an hypobaric atmosphere for 10 hours daily during the first ten postnatal days, thus causing a moderate chronically intermittent hypoxia. After a three months life under normal conditions the now adult rats were sacrificed and the dentate area of the hippocampus was examined for posthypoxic ultrastructural changes. By means of a quantitative stereological method the cytoplasm of the neurons in the granular layer of the hippocampal formation was analyzed. The absolute number of ribosomes was found to be unchanged after 3 months recovery from early postnatal hypoxia. However, the rough endoplasmic reticulum in cells of postnatally hypoxia exposed animals showed lengthened membranes that were significantly less dense equipped with ribosomes. Most striking was an enhancement in the number of free polysomes. Thus, a permanent disturbance in the quality of the proteinsynthesis capability of these neurons was shown to be a long-lasting effect of postnatal hypoxia.

Animals↗
PubMed1987

Fatal copper storage disease of the liver in a German infant resembling Indian childhood cirrhosis.

A female child of non-consanguineous, healthy German parents fell ill at the age of 7 months with a progressive liver disease leading to irreversible hepatic failure 3 months later. Histological examination revealed severe liver cell necrosis, excessive Mallory body formation and veno-occlusive-like changes associated with massive storage of copper, similar to Indian childhood cirrhosis (ICC). Chronic copper contamination of drinking water was the only detectable aetiological factor. The study illustrates that ICC most probably is an environmental disease, also occurring outside the Indian subcontinent, and is likely to be underdiagnosed in the Western world.

Child↗
PubMed1987

[Not Available].

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Germany↗