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Biomedical subjects

M Oehmichen

Publications and source records attributed to M Oehmichen.

At least 91 records · Page 5Linked to original sources
PubMed1986

[Immunocytochemical identification of AB0 incompatible erythrocytes following fatal transfusion reaction].

A patient with blood group O died 8 h after an accidental transfusion of one unit of A1 erythrocytes. The admixture of group A red cells was not detected during postmortem serology. Paraffin-embedded autopsy material was studied by the indirect immunoperoxidase technique using monoclonal antibodies. Group A red cells were easily identified as circulating agglutinates in the larger vessels, in the capillary vessels of all organs examined, and as closely packed cell aggregations in the sinuses of the spleen. However, there was no clear evidence of erythrophagocytosis in the spleen or in liver.

Aged↗
PubMed1986

[Form variants of globular hyaline microthrombi. Light microscopy, immunohistochemical and scanning and transmission electron microscopy observations].

Globular hyaline microthrombi are characterized by their diameter (2-30 micron), globular form, and positive PAS and PTAH reaction. They are a morphologic indicator of disturbed microcirculation and hemostasis, such as that occurring in shock. In two of our cases, we observed large globular hyaline microthrombi, some with central webbed degradation progressing to the formation of closed or open hollow globules. The electron microscopic findings were similar to those observed by other investigators in typical shock bodies. On the basis of the morphologic findings, the authors conclude that degradation phenomena start at the center of globular hyaline microthrombi and can progress to the surface where accelerated fibrinolysis is possible. The cellular elements that other investigators have described as a possible condensation center for fibrin precipitate proved to be structurally intact cells that are apparently located in niches of open hollow globules or in the center of circular hyaline microthrombi. The diagnostic relevance, vitality, and temporal classification are discussed.

Adult↗
PubMed1986

[Intravital acellular hemolysis of extravascular erythrocytes. An experimental contribution to the determination of wound age].

The time-dependent acellular, destructive changes in erythrocytes was investigated in rabbits by subcutaneous, intraperitoneal, and subdural implantation of blood-filled diffusion chambers with 0.45 micron pores. The animals were killed at various intervals after implantation (7-24 h), and the erythrocytes in the capsules were examined by light and electron microscopy. The findings were quantified by counting 100 cells per preparation under the light microscope; changes in both matrix and membrane structure were recorded. Matrix changes and membrane variants were specified by electron microscopy. Time-dependent changes in erythrocyte matrix and membrane were established, which occurred at the various localizations in an identical sequence, but with different time intervals. The destructive changes were: an increase in loss of matrix, increase in membrane permeability, and decrease in membrane stability. The physiologic bases of and the conclusions for wound timing were discussed.

Animals↗
PubMed1986

Brain macrophages in human cortical contusions as indicator of survival period.

The aim of this study was to establish a morphologic time scheme with which cases of cerebral contusion with unknown survival periods can be dated. Our study of 275 cases was limited to qualitative and quantitative changes in macrophages. The appearance of macrophages and their distribution as well as their content of neutral fat, esterified cholesterol, erythrocytes, siderin, hematoidin, and ceroid were correlated with the survival period. For each cytologic criterium, the observation period, distribution-free limits of tolerance, and relative frequency of identification in different survival periods were determined, and the limits of confidence calculated. The findings permit the dating of trauma in cases with unknown survival periods. Moreover, the probability of this dating was calculated.

Adolescent↗
PubMed1986

Recovery of monkey brain after prolonged ischemia. II. Protein synthesis and morphological alterations.

Recovery of protein synthesis following 1 h of complete ischemia of the monkey brain was assessed by 3H-labeled amino acid incorporation in vivo at various postischemic periods between 1.5 and 24 h. The regional autoradiographic patterns obtained were compared on the basis of precursor-product relationships determined biochemically at the end of the tracer incorporation studies. Shortly after ischemia, protein synthesis was severely inhibited, but it gradually recovered with increasing recirculation times. In the cerebellum it returned to almost normal levels within 3 h and in the cortex within 24 h. Hippocampal and thalamic regions, however, did not recover control levels of protein synthesis at 24 h. Histoautoradiographic evaluation of amino acid incorporation in individual neurons revealed recovery of pyramidal neurons in the CA1 and CA3 sectors of the hippocampus within 6 h of recirculation, which, however, was followed by secondary inhibition after longer recirculation. Neurons in cortical layer 5 steadily recovered to near control within 24 h, with the exception of those located in arterial border zones, which returned to only 50% of control at 24 h. Incomplete recovery was also observed in thalamic neurons and Purkinje cells. The regional and histoautoradiographic pattern of protein synthesis correlated with the morphological appearance of cells. Ischemic cell changes (mainly of the dark type with microvacuolization and perineuronal glial swelling) were marked after short recirculation times but gradually disappeared in parallel with the return of protein synthesis in most regions of the brain. Only in pyramidal cells of the hippocampus, thalamic neurons, and Purkinje cells were changes not reversed during the observation period. The results obtained corroborate the electrophysiological observations reported in the first part of this investigation and support the notion that the majority of the neurons of monkey brain survive complete cerebrocirculatory arrest of 1 h for at least 1 day.

Amino Acids↗
PubMed1986

[Postmortem transport of gastric contents?].

For the determination of the time since death, the distribution of the last meal in the stomach and small bowel may be of great importance. It may be even more difficult to estimate the time if there is a possibility that postmortem peristaltic emptying of the gastric content occurs, as has been claimed. Radiological control immediately after death by means of applying barium sulfate to the stomach, however, revealed no evidence of peristaltic emptying of the gastric content after death.

Animals↗