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Biomedical subjects

H E Schaefer

Publications and source records attributed to H E Schaefer.

At least 109 records · Page 6Linked to original sources
PubMed1985

Megakaryoblastic micromegakaryocytic crisis in chronic myeloid leukemia.

Atypical megakaryoblasts (MKB) or megakaryocytes (MK) are occasionally present in the peripheral blood during the terminal development of chronic myeloid leukemia (CML). We report on a 49-year-old female suffering from Ph1 chromosome-positive CML with typical megakaryoblastic transformation in the peripheral blood and in the bone marrow. The small "blasts" were at the most only slightly larger and were occasionally even smaller than lymphocytes but showed megakaryoblastic or atypical megakaryocytic differentiation. The cytoplasmic cytochemical pattern of the atypical megakaryocytic cells was identical to that of large atypical thrombocytes. Platelet peroxidase was detected upon electron-microscopic (EM) examination. Immunologic characterization disclosed the presence of MK-specific antigens. When cultured in vitro on agar, the blasts transformed spontaneously into large mature MK, exhibiting characteristic cytochemical and immunological patterns. Cytogenetic examination of peripheral blood showed severe abnormalities. The patient did not respond to therapy and died 3 months after manifestation of the blast crisis.

Bone Marrow Cells↗
PubMed1985

Beta-glucuronidase-positive erythrocytic inclusion bodies--a hitherto unknown phenomenon.

A combined cytochemical and electron microscopical study has delineated a new type of an erythrocytic inclusion body. Enzyme cytochemically these inclusions are characterized by beta-glucuronidase as a marker enzyme. In part, the inclusions may contain acid phosphatase and ferritin. The inclusions develop in mature erythrocytes since beta-glucuronidase normally does not occur in erythroblasts and, in general, this type of inclusion body is not found in erythroblasts. Based upon our preliminary findings, the hypothesis is extended that beta-glucuronidase is taken up via receptor-mediated endocytosis into erythrocytes and is finally put into clustered cytolysosomal vaculoes, that account for the inclusion bodies as seen at light microscopy. Exogenous beta-glucuronidase might be contributed for by breakdown of cells (e.g. hepatocytes) producing this enzyme in considerable amounts numbers. This view is corroborated by the observation that most patients with beta-glucuronidase-positive inclusions suffered from various chronic disorders of the liver.

Acid Phosphatase↗
PubMed1985

Aplastic anaemia and the hypocellular myelodysplastic syndrome: histomorphological, diagnostic, and prognostic features.

In a retrospective study of 111 patients with aplastic anaemia iliac crest biopsies were evaluated for the presence of morphological features statistically related to the evolution of the disease. Prognostic variables for a transition to acute non-lymphatic leukaemia were: cellular atypias of the three haemopoietic lineages, as observed in the myelodysplastic syndrome, and especially "micromegakaryocytes"; high numbers or irregular distribution of megakaryocytes, or both; and (slight) marrow fibrosis. Clinical variables did not influence these prognostic correlations. Prognosis in relation to death from bone marrow failure without leukaemia might well have been influenced by a strong plasma cell reaction, but this correlation was weakened by clinical factors. On the basis of this study aplastic anaemia can thus be subdivided morphologically into two disease entities--namely, hypocellular myelodysplastic syndrome with a 23-82% risk of acute non-lymphatic leukaemia developing within three years, depending on how many variables associated with acute non-lymphatic leukaemia are present, and non-dysplastic myelohypoplasia.

Adolescent↗
PubMed1985

[Cytochemical differentiation of T- and B-lymphocytes in the short-tailed mouse (Clethrionomys glareolus)].

Using the cytochemical demonstration of alkaline phosphatase (AP) two different populations of lymphocytes are seen in the short-tailed mouse Clethrionomys glareolus: AP-positive and PA-negative lymphocytes. The aim of this study was to find out as to whether in this species AP represents a cytochemical marker for differentiating T- and B-lymphocytes. For this purpose, we analysed the frequency of AP-positive lymphocytes in the peripheral blood, bone marrow, thymus, lymph node, spleen, and Peyer's patches of normal adult animals 3 months after neonatal thymectomy, and at varying times following administration of intraperitoneal injections of a maximum dose of 16-methylenprednisolone. In normal mice the frequency of AP-positive lymphocytes in peripheral blood and bone marrow corresponds to that of T-lymphocytes in other species. In the thymic cortex, nearly 100% of the lymphocytes show an AP-positive reaction. In the peripheral lymphatic organs these cells are prevailing in the T-dependent areas (paracortex of lymph node, periarteriolar lymph sheet of spleen, and serosa-near region of Peyer's patches). Neonatal thymectomy as well as administration of corticosteroid cause a significant loss of enzyme-positive lymphocytes in the organism. This T-cell reduction becomes particularly evident in B-dependent regions, because in these areas AP-positive (T-) and AP-negative (B-) cells are usually intermingled, and this provides the necessary condition of T/B-interaction, which is of immunological significance. In T-dependent zones, populated mainly by AP-positive cells, neonatal thymectomy results in overall atrophy, while T-cell depletion, expressed as a percentage, is less pronounced within these atrophied areas. Based on these findings the conclusion may be drawn that in Clethrionomys glareolus committed thymocytes, recirculating T-lymphocytes as well as T-helper cells show an AP-positive reaction in contrast to prethymic T-cells, T-suppressor cells and B-cells, which do not express this enzyme. The histochemical demonstration of lymphocytic AP therefore permits an easy visualisation and quantification of T-lymphocytes in Clethrionomys glareolus.

Alkaline Phosphatase↗
PubMed1983

[Thrombopoiesis, thrombocyte count and thrombocyte function before and following cell separation].

About 50% of the circulating platelets can be taken from healthy donors by means of the cell separation technique. In order to investigate the effect of cell separation on thrombopoesis bone marrow samples were taken from 12 voluntary donors up to 5 times. The megacaryocytes were analyzed before and after cell separation by morphometric measures and determinations of platelet count and platelet function (adhesion, aggregation, spreading, retraction) were carried out. Removing of large amounts of platelets form the circulation by stimulation of thrombopoesis resulted in an increase of the peripherical platelet count already 48 h after cell separation. Of the platelet functions tested only aggregation induced by collagen was found to be increased after cell separation as compared to that before the procedure.

Blood Platelets↗
PubMed1982

On the pathogenesis of preleukemic myelodysplastic syndromes: development of a dysplastic hemopoietic proliferation in the rat after a single pulse dose of dimethylbenz(a)anthracene (DMBA).

After a single pulse dose of DMBA, rats develop bone-marrow hypoplasia, which is almost compensated for by regeneration after 16 weeks. Subsequently, dysplastic signs of hemopoiesis appear in all experimental animals as massive extrusion of normoblasts into the peripheral blood, red-cell aniso- and poikilocytosis, nuclear deformities, atypical mitoses, and PAS-positivity, as well as megaloblastoid maturation dissociation of erythroblasts and nuclear and granulation anomalies of neutrophilic granulocytes and monocytes, comparable to human "pseudo-Pelger cells" and "paraneutrophils". At the time of death (112-497 days after DMBA pulse) experimental animals showed hyperplastic bone marrow with increased granulopoietic/erythropoietic ratios and an augmented, mainly erythropoietic, hemopoiesis in the spleen, with splenomegaly in six rats. Splenic hemopoiesis is accompanied by white pulp atrophia. The cause of death was septicopyemia in three rats, anemia in three, and bleeding in one rat. None of the animals developed a leukemic blast phase. Myelodysplastic changes in this experiment are the same as have been shown to precede leukemia in rats treated with five DMBA pulses (Fohlmeister et al. 1981). Possible relations of myelodysplasia and leukemia are discussed.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

[Demonstration of apolar lipids in paraffin-embedded tissues with special reference to pathological fatty degeneration in Tangier disease and other dyslipoproteinemias].

The oxidative cross-linking effect exerted by OsO4 on lipids and the blackening of osmiophilic structures resulting from reduction of OsO4 constitute long-known phenomena. Nevertheless, osmic acid has rarely been used for lipid staining as various even non-lipid-containing tissue structures are more or less intensively blackened by OsO4. If one treats osmicated tissue sections with certain oxidants (e.g. ammonium persulfate) in aqueous solution, then all the black OsO4 reduction products which are exposed to the aqueous phase are oxidized and thereby bleached. This applies e. g. to all proteins and polar (hydrophilic) lipids. Only apolar lipids retain their more or less black color and can be stained subsequently with Sudan dyes. Based on this principles, a new procedure has been developed which is effective on paraffin sections obtained after previous block osmication. This OBS procedure can also be used for very precise localization of appropriate lipid structures as can be demonstrated in cases of pathologic lipid deposits in an-alpha- and in a-beta-lipoproteinaemia, in type III hyperlipoproteinaemia, and in diverse other dyslipoproteinaemias as well.

Abetalipoproteinemia↗