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Biomedical subjects

R Fischer

Publications and source records attributed to R Fischer.

At least 541 records · Page 30Linked to original sources
PubMed1987

Synthesis of nucleosomal histone variants during wheat grain development.

The synthesis and distribution of histone subfractions (variants) were investigated during early grain development and in mature tissues of wheat (Tritium aestivum L.). Histones were extracted from purified chromatin and separated by two-dimensional polyacrylamide gel electrophoresis. There were no detectable differences in the patterns of histone variants from immature grain (3-16 days after fertilization), from mature embryos, from coleoptiles and roots of 4-day-old, etiolated seedlings and from leaves of 10-day-old, light-grown seedlings. Wheat H2 histones are composed of families of closely related variants. H2A consists of three major variants, and H2B consists of two major and four minor variants. The synthesis of these variants during early grain formation was determined by calculating the specific activities of the [3H]lysine-labeled proteins synthesized between 3 and 10 days after fertilization. The rate of synthesis of the nucleosomal histones closely parallels the declining rate of cell division in developing grains. Our results indicate that all the recognized wheat histone variants are present in developing wheat grains from the earliest time investigated (3 days after fertilization) and persist with no detectable changes in relative quantities throughout grain development and in several mature tissues.

Genetic Variation↗
PubMed1987

The use of the anti-factor VIII method on trephine biopsies of the bone marrow for the identification of immature and atypical megakaryocytes in myeloproliferative diseases and allied disorders. A morphometric study.

A morphometric analysis was performed on trephine biopsies of the bone marrow to identify atypical megakaryocyte proliferation following PAS staining and the immunohistological demonstration of factor VIII. This study includes nine patients with a megakaryoblastic crisis in chronic myeloid leukemia (CML), four with acute megakaryoblastic leukemia (AM) and three with myeloid dysplasia later evolving into overt acute leukemia. Comparison and statistical evaluation of the PAS reaction with anti-factor VIII staining reveals that the latter technique not only facilitates the recognition of immature and abnormal megakaryocytes, but leads to a significantly increased count for all megakaryocytic elements in the bone marrow. Thus our retrospective investigation of routinely processed and paraffin-embedded trephine biopsies shows that the diagnosis of a megakaryoblastic crisis in CML as well as AM may be easily established with the aid of the anti-factor VIII method. In all cases of megakaryoblastic proliferation in CML and AM, the appearance of blasts was associated with moderate to pronounced myelofibrosis which could be also determined by morphometry.

Adult↗
PubMed1987

Arogenate dehydratase.

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Chromatography, DEAE-Cellulose↗
PubMed1987

Chronic myeloproliferative diseases with an elevated platelet count (in excess of 1,000,000/microliter): a clinicopathological study on 46 patients with special emphasis on primary (essential) thrombocythemia.

A clinicopathological study was performed on 46 patients with chronic myeloproliferative diseases (CMPD) showing a thrombocythemia in excess of 1,000 x 10(9)/liter. When applying rigid diagnostic criteria only 23 patients were compatible with the initially suspected diagnosis of primary thrombocythemia (PTH). Comparison of PTH with the other entities of CMPD (CGL, 10, AMM, 6, and polycythemia, 7 cases) revealed a sustained elevation of the platelet count observable over a period of 2 to 8 years, no marked leukocytosis or abnormalities of the differential blood count, and a normal score of the leukocyte alkaline phosphatase. Episodes of hemorrhage and thrombosis as well as neurological symptoms (paresthesias, dizziness, headache), were encountered frequently as clinical manifestations in PTH. Survival time in PTH was significantly longer than in CGL with accompanying thrombocythemia. In a consecutively biopsied population of patients with CMPD, incidence of PTH was about 8%. In PTH the characteristic histopathology of the bone marrow consisted of an isolated (monolinear) proliferation of the megakaryocytes (density 127 +/- 47/mm2) without gross abnormalities of this cell lineage or a conspicuous increase in neutrophilic granulo- or erythrocytopoiesis. These lesions are significantly different from the morphological findings in the other CMPD with extreme thrombocytosis.

Actuarial Analysis↗
PubMed1987

[Stenosis of biliobilary anastomoses and its prevention by ring splinting outside the lumen--results of an animal experiment study].

The causes of the stenosing and their prevention were investigated by means of a ring splinting outside of the lumen in 19 dogs. The dogs were relaparotomised 3, 6, and 12 months after division and reanastomosis of the supra-duodenal choledochus. In contrast to the therapy group (n = 6) the control group shows a statistically significant stenosis of the anastomosis and a dilatation of the proximal bile passages. The stenosis of the anastomosis is caused by a circumscribed cicatricial contraction. This can be held up effectively by a ring splinting outside of the lumen.

Animals↗
PubMed1986

Metabolic conversion of L-[U-14C]phenylalanine to respiratory 14CO2 in healthy subjects, phenylketonuria heterozygotes and classic phenylketonurics.

Ten healthy volunteers, 12 classic phenylketonuria (PKU) heterozygotes, and 5 classic phenylketonurics have been loaded orally with a mixture of 5 microCi of L-[U-14C]phenylalanine plus 25 mg/kg of L-[2H5]phenylalanine. For 3 h thereafter, carbon-14 activity in expired air and total carbon dioxide were measured continuously and the levels of L-phenylalanine and L-tyrosine in plasma were determined in six blood samples. After 3 h, 15.1 +/- 2.1% of the applied dose of radioactivity was recovered in the expired air of the healthy subjects, compared to 10.1 +/- 2.2% for PKU heterozygotes and 0.32 +/- 0.18% for classic phenylketonurics. The integrated activity expired provides a discrimination between normals and PKU heterozygotes with a classification error of about 13% compared to an error of about 9% based on the fasting L-phenylalanine over L-tyrosine ratio. A combination of these two parameters in a two-dimensional discriminatory analysis reduces the classification error to less than 1%. An intraindividual correlation between the absolute activity expired and the formation of L-[2H4]tyrosine formed is shown, confirming that ring hydroxylation of L-phenylalanine to L-tyrosine is mandatory in the catabolism of L-phenylalanine to carbon dioxide.

Breath Tests↗