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Biomedical subjects

A Schulz

Publications and source records attributed to A Schulz.

At least 199 records · Page 11Linked to original sources
PubMed1986

Metabolic alterations associated with proliferation of mitogen-activated lymphocytes and of lymphoblastoid cell lines: evaluation of glucose and glutamine metabolism.

In vitro resting, short-term mitogen stimulated, and proliferating rat thymocytes as well as established human T and B lymphoblastoid cell lines were compared in their capacity to metabolize glucose and glutamine as energy source. Furthermore, the pathways of glutamine metabolism in these cells were studied. Compared with resting thymocytes, glucose metabolism of proliferating thymocytes was 36-fold increased during the incubation; 92% of the amount of glucose utilized was converted into trioses mainly lactate, whereas resting cells metabolized only 38% to trioses. However, the latter oxidized 19% of glucose to CO2, as opposed to 1.1% by the proliferating cells. Rates of glucose uptake and degradation to products by the malignant T lymphoblastoid cell line (Jurkat) were nearly identical with those observed with proliferating rat thymocytes, whereas the benign B lymphoblastoid cell lines (DHg-B-1 and LV-B-1) showed significantly higher rates of glucose metabolism. All three transformed lymphoblastoid cell lines, however, metabolized glucose almost completely to lactate as did the proliferating rat thymocytes. Lymphocytes are able to utilize glutamine with glutamate, aspartate and ammonia being the major end-products. A complete recovery of glutamine carbon in the products was obtained with all cells. Glutamine utilization by incubated proliferating rat thymocytes was 8-fold increased as compared to the resting cells. Again the human T lymphoblastoid cell line showed the same rates of glutamine uptake and conversion into products as did the proliferating rat thymocytes, whereas both B lymphoblastoid cell lines had about 2.5-fold enhanced rates as compared to the T cell line. The results indicate that during lymphocyte proliferation caused by mitogen stimulation as well as by permanent transformation into lymphoblastoid cell lines glucose metabolism is altered not only quantitatively but also qualitatively by changing from partly aerobic to almost complete anaerobic glucose breakdown. Glutamine has been found to be a suitable energy source for lymphocytes. About 75% of the amount of glutamate derived from glutamine entered into the citric acid cycle via the aspartate aminotransferase, and the remaining 25% via the glutamate dehydrogenase reaction. The changes in metabolic rates observed in proliferating as well as in transformed or leukemic lymphocytes appear to be reliable parameters to characterize the state of lymphocyte activation or to evaluate the efficacy of lymphokines.

Animals↗
PubMed1986

S-100 protein in amelanotic melanoma. A convenient immunocytochemical approach compared to electron microscopy.

16 amelanotic melanomas were investigated immunocytochemically using two different antibodies against S-100 protein. In six cases electron microscopy was carried out. All 16 tumors showed a positive reaction for both antisera in epithelioid as well as in spindle-shaped tumor cells. Ultrastructurally the six investigated tumors contained stage II to IV melanosomes. Immunocytochemical and electron microscopical results are compared and discussed with regard to their significance in routine surgical pathology.

Adult↗
PubMed1986

Absorption, elimination and metabolism of trichloroethylene: a quantitative comparison between rats and mice.

The absorption, elimination and metabolism of 14C-trichloroethylene (Tri) was studied in adult female Wistar rats and NMRI mice after administration of 200, 20 and 2 mg/kg Tri. Dose-dependent biotransformation of Tri to metabolites was observed in both species. Induction of hepatic mono-oxygenases by phenobarbital or polychlorinated biphenyls resulted in a higher rate of biotransformation after a single oral dose of 200 mg/kg 14C-Tri to rats. An increase in radioactivity covalently bound to liver and kidney macromolecules of induced rats as compared to control rats parallels the toxic effects of Tri on these organs after induction of cytochrome P-450. The urinary metabolites were analysed by h.p.l.c. In both species, 1,1,1-trichlorocompounds (trichloroacetic acid, trichloroethanol and its glucuronide, comprising 88.9-93.5% of the radioactivity excreted in the urine) constituted the main metabolites; in addition, N-(hydroxyacetyl)-aminoethanol (4.1-7.2%), dichloroacetic acid (0.1-2.0%) and oxalic acid (0.7-1.8%) were identified. The pattern of metabolites in the 72 h urine remained constant for each species in the dose range studied and no change was induced by pretreatment. The percentage of radioactivity exhaled as 14CO2 increased with dose in mice, which may indicate dose-dependent formation of dichloroacetic acid and saturation of deactivating mechanisms for reactive intermediates in mice.

Animals↗
PubMed1984

Small cell neuroendocrine (oat cell) carcinoma of the male breast. Immunocytochemical and ultrastructural investigations.

A case of small cell neuroendocrine (oat cell) carcinoma of the breast in a 52-year old male is presented. Oat cell carcinomas have been reported in various extrapulmonary sites, but this is the second case of a primary oat cell carcinoma of the breast and the first one to have been documented in a male. The tumor was investigated histologically, immunocytochemically and ultrastructurally. The relationship to so-called "carcinoid" mammary tumors is discussed.

Breast↗
PubMed1984

Tumor cytotoxicity of human macrophages after incubation with synthetic analogues of 2-lysophosphatidylcholine.

Human alveolar macrophages as well as macrophages derived from Teflon culture of blood-borne monocytes were incubated with synthetic analogues of 2-lysophosphatidylcholine and then tested for their cytotoxic capacity against an allogeneic lymphoma cell line. Metabolic, rather stable analogues enhanced macrophage cytotoxicity significantly. This phenomenon was shown both in a growth-inhibition assay as well as in the 51Cr release assay. Macrophage activation was dose- and time-dependent and was potentiated at temperatures above 37 degrees C. Incubation of the macrophages with the active compounds induced characteristic changes in cell morphology as revealed by scanning electron microscopy.

Antineoplastic Agents↗
PubMed1984

Effect of growth hormone on osteoblasts and demonstration of somatomedin-C/IGF I in bone organ culture.

Bone organ culture makes it possible to observe the direct influence of hormones on bone cells. We studied the effect of growth hormone in vitro on embryonal rat tibiae during culture for 7 days, functionally by measuring the levels of alkaline phosphatase in the culture medium, and morphologically by means of semi-thin sections and electron microscopic examination. Since growth hormone (GH) is supposed to exert an indirect effect on bone cells, somatomedin-C/insulin-like growth factor I (SM-C/IGF I) as a possible mediator was also measured radioimmunologically in the culture medium. In the controls alkaline phosphatase levels showed a continuous increase up to the 7th day which was significantly higher in the presence of GH. There was also a significantly enhanced increase of SM-C/IGF I in the presence of GH during culture in comparison to the controls. Evidently IGF I is produced locally in bone and mediates the effect of GH on bone formation.

Alkaline Phosphatase↗
PubMed1983

Enhancement of spontaneous and lymphokine activated human macrophage cytotoxicity by hyperthermia.

Human macrophages grown on hydrophobic teflon membranes from blood-born monocytes were incubated at hyperthermic temperatures for various time periods and then tested for their ability to inhibit the growth of an allogeneic lymphoma cell line (U 937). Incubation at 40.5 degrees C greatly enhanced macrophage cytotoxicity. This effect of hyperthermia developed slowly with an optimal incubation period of 48 h. In addition, lymphokine activation of macrophages for cytotoxicity appeared to be more effective at elevated temperatures.

Cell Line↗
PubMed1983

Localised (circumscribed) nodular synovitis (histiocytic xanthogranuloma).

Localised nodular synovitis is a benign tumour which originates from the synovia. The circumscribed nodules are characterised by multinucleated giant cells associated with the proliferation of histiocytes. There is a histiogenetic relationship to the diffuse, heavily pigmented, villo-nodular form. The treatment consists in excising the complete nodule.

Adult↗
PubMed1983

[Therapeutic response of various histological osteosarcoma subtypes to high-dose methotrexate treatment].

The successful or unsuccessful chemotherapy of osteosarcoma has given rise to the division of these tumors into responders and non responders from the clinical point of view. In order to work out drug sensitive tumor components we studied 9 osteosarcomas by a histological subdivision of the osteosarcoma tissue into 6 subtypes. Seven of the 9 osteosarcoma patients had developed lung metastases under adjuvant high dosage methotrexate (HDMTX) therapy. The aim was to identify the components of the primary tumors which had endured HDMTX-therapy as lung metastases. As HDMTX-sensitive histologic differentiation form of osteosarcoma tissue we regarded the no matrix producing-subtype (III), because it did not occur in the lung metastases. The classical subtype (IV) seems to be only partially sensitive because the corresponding lung metastases showed a higher osteoblastic differentiation with increased osteoid production. No therapeutic effect could be observed in the chondromatous (I) and in the sarcomatous (II) subtypes as well as in the two subtypes with intensive osteoid production being termed trabecularly sclerosing (V) and massively osteoid producing subtypes (VI).

Adolescent↗
PubMed1983

Cytotoxic effector cell function at different stages of human monocyte-macrophage maturation.

Human blood-borne monocytes were cultured for up to 22 days on disposable Teflon foils. Within 8 days, these monocytes developed into mature macrophages. At various stages of differentiation, the cells were recovered from the hydrophobic membrane and were assayed for typical monocyte-macrophage enzymes and morphology, binding of monoclonal antibodies (OKM1, OKla1), Fc and transferrin receptors, phagocytic activity, lysozyme production, and ability to inhibit the growth of an allogeneic tumor target cell line (U937). A significant antitumor activity of mature macrophages was found, which developed along with the differentiation of the monocyte precursor cells. In addition, cytotoxic effector macrophages could be activated by lymphokine-rich medium and synthetic alkyl-lysophospholipids. After density gradient separation, light cells (less than 1.05 and less than 1.06 g/ml) showed enhanced cytotoxicity, whereas cells from the dense fraction (greater than 1.06 g/ml) with low base-line activity could be best activated for cytotoxicity by lymphokines. If monocyte-macrophages are involved in a natural surveillance mechanism, our results may indicate the importance of unimpaired macrophage maturation to generate effective host defense against tumor development.

Cell Adhesion↗