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Biomedical subjects

A Georgii

Publications and source records attributed to A Georgii.

At least 181 records · Page 10Linked to original sources
PubMed1977

Freeze-fracture of the normal and pathological megakaryocyte lineage in chronic megakaryocytic-granulocytic myelosis.

Freeze-fracture and thin sections were performed on human bone marrow of chronic megakaryocytic-granulocytic myelosis (CMGM) to study the three-dimensional fine structure and maturation of normal and atypical megakaryocytes and thrombocytes. In the many normally maturing megakaryocytes the development of the demarcation membrane system (DMS) was best investigated by comparison of thin sections with freeze-fracture replicas. The DMS shows no connections with the Golgi apparatus or rough-surfaced endoplasmic reticulum, but originates from tubular infoldings of the plasma membrane. These infoldings are always in continuity with the extracellular space and form an intracellular membranous pool by branching and coalescing of flattened tubules from which finally the perforated cisternae of the DMS arise. Freeze-fracture of the normal thrombocytes confirms earlier findings. The abnormal giant platelets seen in CMGM display extensive areas of smooth membranes of a spongy structure consisting of dense tubules surrounded by the labyrinth of the surface-connected system. Their physiological significance in these atypical platelets remains unsolved.

Blood Platelets↗
PubMed1976

Hairy cell leukemia. Bone marrow findings in 24 patients.

In 24 patients with hairy cell leukemia, histological and fine structural findings from biopsies of the bone marrow are reported and their validity is compared with other diagnostic procedures available. Diagnosis by light microscopy of anterior iliac crest biopsies obtained by the method of myelotomy is possible with a high degree of accuracy. The differentiation of hairy cell leukemia from other myelo- or lymphoproliferative disorders based on cytomorphology as well as patterns of growth is emphasized. Morphological differences between fibrosis in this entity and other lesions such as malignant lymphomas, Hodgkin's disease, osteomyelofibrosis and -sclerosis are emphasized. Electron microscopy of the bone marrow shows single fibroblastic cells with numerous slender cytoplasmic processes randomly dispersed among the hairy cells. These fibroblasts are probably responsible for the synthesis of the reticulin and collagen fibres in their surroundings. Moreover fine structur of the hairy cells demonstrates pinocytic activity but no apparent phagocytosis in contrast to the phagocytic reticulum cells (histiocytes, macrophages). In the bone marrow the precursor cells and the many immature forms of hairy cells exhibit an overall lymphocytoid appearance during their maturation, suggesting a lymphocytic origin.

Adult↗
PubMed1976

Histochemical and immunohistochemical techniques on acrylate embedded bone biopsies.

Till present the advantages of methacrylate embedded bone biopsies for the diagnosis of haemoblastic disorders have been somewhat restricted. This was a result of the impossibility to apply histochemical methods and other sensitive staining procedures to semithin sections. A routine method is described whereby enzyme activity, excellent fixation and good sectioning ability are retained. Fixation is carried out using 4% purified formaldehyde buffered in 0.1M sodium cacodylate. Dehydration is done with a water-miscible glycolmethacrylate. Naphthol-AS-D-chloroacetate esterase activity can be observed in granules of the entire neutropil cell lineage. By use of this method it becomes possible to demonstrate acid phosphatase activity and immunoglobulins in atypical plasma cells of multiple myeloma. A considerable decrease in processing time, as well as a preservation of enzyme activity during the postal mailing of fixed tissue samples from outside are further advantages.

Acrylates↗
PubMed1976

Ultrastructure of chronic megakaryocytic-granulocytic myelosis.

To study chronic megakaryocytic-granulocytic myelosis, bone marrow biopsies from 5 patients were obtained. Ultrastructural quantitative and qualitative assessments demonstrate proliferation of both the megakaryocytic and granulocytic cell lines. Factors indicative of malignant growth in megakaryocytes included atypical maturation, nuclear-cytoplasmic asynchrony, nuclear inclusions and production of micromegakaryocytes. Abnormal thrombocyte delineation provoked giant platelet production. The neutrophil series also presented atypia as generally observed in chronic myelogenous leukemia. Even in cases without evidence of myelofibrosis under the light microscope, megakaryoblasts were associated with fibrillar structures. These cells may be responsible for the initial step in fibrillogenesis by providing a medium conductive to the collagen formation found in later stages of this disease.

Blood Platelets↗
PubMed1976

Influence of vaccination with A/PR 8/34 (HO-N1) influenza virus on the oncogenic activity of polyoma virus in newborn Wistar rats.

Vaccination with the A/PR 8/34 (HO N1) strain of influenza virus can decrease significantly the oncogenic activity of polyomavirus in newborn Wistar rats. This effect was regularly observed when animals were vaccinated with 24 hr after birth, whereas vaccinations performed on Days 3 and 10 failed to influence the oncogenic potential of polyoma virus. In 3 series of experiments, influenza virus vaccination resulted in sigificantly decreased tumor rates, and, in a 4th series, in reduced tumor growth only. Heat inactivation of influenza virus failed to abolish its influence on the oncogenicity of polyoma virus. In most of the experiments, the antibody response to influenza virus was enhanced by inoculation of animals with polyoma virus. In contrast, polyoma virus antibody titers were, in some experiments, decreased, and, in others, not influenced by vaccination with influenza virus.

Animals↗
PubMed1975

[Special and functional pathomorphology of parathyroid glands as revealed in non-selected autopsies (589 cases) (author's transl)].

1637 parathyroid gland dissections were performed on 589 unselected autopsy preparations in order to study both pathomorphology and functional aspects in an unselected group of patients. In no case had primary or tertiary hyperparathyroidism been suspected clinically; but in about 10 patients on chronic hemodialysis, a secondary hyperplasia of the glands was known. In about 33% of the cases pathological changes were observed: 3 chief cell adenomas, 3 adenomas combined with hyperplasia, 12 primary nodular hyperplasias including 6 microadenomas and 145 cases with secondary regulative hyperplasia. Cysts, purulent parathyroiditis, lipomatous pseudohyperplasia, metastases of carcinomas, hemorrhagic infarctions and amyloidosis were also detected in serial sections of the parathyroid glands. The remarkably large group of secondary hyperplasias (about 20%) was divided into 3 categories according to weight and cytology. The first category (118 cases) was characterized by a lack of the normal age-related involution of the parenchyma and prevalence of light (active) chief cells. Statistical evaluation of the other autopsy findings, histomorphology of the bone in particular, led to the conclusion that this group represented a slightly activated gland with possibly reversible hyperplasia, mostly connected with pathological alterations in the kidney and with minimal changes in bone morphology consistent with hyperparathyroidism. The microadenomas displayed different levels of endocrine activity as demonstrated by bone histology in accordance with the cytology of the adenomas (dark or resting chief cells versus active chief cells and waterclear cells). No specific alterations with respect to endocrine function could be attributed to diffuse and nodular hyperplasia of oxyphil (oncocytic) cells except their increase with age and arteriosclerosis, especially in women.

Adenoma↗
PubMed1975

[Xenotransplantation of established tumor cells in congenital thymusless "nude" mice (author's transl)].

Successful xenotransplantation of 5 different established tumor cell-lines was performed in the congenital thymusless mouse mutant "nude". The tumors were one human carcinoma of the cervix (HeLa), one Burkitt's lymphoma as well as two Polyoma virus-induced tumors from rats and one spontaneous tumor from hamster. During an observation period of 21-28 days all cells formed rapidly growing tumors at the injection site. The critical cell dose varied in the different lines between 10-4 and 10-6 cells. Histological appearance of the neoplasias resembled that of the primary tumors. Two established lines from normal fibroblasts (3-T-3) and kidney (CV-1) failed to grow. Our results indicate that xenotransplantation in "nude" mice may serve as a simple in-vivo assay for testing the oncogenicity of tissue culture cells.

Animals↗
PubMed1975

[Multicentric carcinoma and atypical hyperplasia of the mammary gland (author's transl)].

A study for multiple primary cancer in the female mammary gland was performed. In 145 cases of mammary cancer, blocks for histological analysis were taken in a special system following routine examination of the specimen. Three sagital sections each of one inch width were taken from the outer, medium and inner region and from each of these 6 small blocks were cut. By this constant pattern of histological screening, 9 cases out of 145 were found showing multiple primary cancers. Among these Carcinoma solidum scirrhosum was the most frequent tumor type. This percentage of 6.2 is considerably lower than that given in the pertinent literature. Residual cancer following biopsy was found in 81% of the 145 cases, although extensive excision had been tried by the first operation. The entity of atypical epithelial hyperplasia which has to be differentiated from Carcinoma in situ was observed in 40.5% including ductal and ductular system.

Adenocarcinoma, Scirrhous↗