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Biomedical subjects

H Schmidt

Publications and source records attributed to H Schmidt.

At least 919 records · Page 51Linked to original sources
PubMed1983

Experimental chronic Trypanosoma brucei rhodesiense infection in Microtus montanus.

Adult Microtus montanus were inoculated with a recently isolated strain of Trypanosoma brucei rhodesiense of human origin. The animals developed subacute to chronic infection and low-grade parasitemia. Histopathological examination of the heart revealed a severe pancarditis resulting in pronounced weight loss, and survival times of 5-8 weeks, preventing development of meningoencephalitis. In the brain a moderate meningitis was found, usually associated with moderate numbers of parasites in the choroid plexus and leptomeninges; however, trypanosomes were also found without tissue inflammation. Meningoencephalitis was found after 7 weeks, with parasites in the cerebral parenchyma. Chronic inflammation was present in lungs and kidney, often associated with trypanosomes; in one animal glomerulonephritis was found. Spleen and lymph glands showed a variable degree of lymphoid hyperplasia but no extravascular parasites. In the liver of all animals plasmolymphoid infiltrates were observed in the periportal connective tissue; no extravascular parasites were observed. A variable degree of lymphoplasmohistiocytic infiltrate in the connective tissue and occasional rare trypanosomes were seen in mesenterium, pancreas, epididymis, striated muscle, and skin. Experimental infection in M. montanus appears to be a suitable model for study of the acute trypanosomiasis of T. b. rhodesiense, but not for chronic African sleeping sickness with cerebral involvement.

Animals↗
PubMed1983

[Histochemical method for determining phenol oxidase in spontaneous rosette-forming cells of human blood].

Using preparations of leucocytes and lymphocytes the reaction of phenoloxidase containing cells (POZ) during the spontaneous rosette formation was investigated. Beside the hitherto known cells forms 3 new types of PO-positive lymphocytes were found. It was established that the large methanol resistent POZ appear in the preparations of lymphocytes, too. Regarding their composition, isolated lymphocytes represent therefore a changing population of cells. Although PO-positive cells take part in rosette forming, the results gave no clear-cut evidence whether T-lymphocytes also contain PO. The application of the PO-reaction opens new aspects in the haematological and immunological diagnostics.

Catechol Oxidase↗
PubMed1983

Immunoprecipitation as a tool for studying humoral immunity of natural and experimental hosts of Herpesvirus saimiri.

Herpesvirus saimiri strain 11 and attenuated H. saimiri strain 11 proteins synthesized during the lytic cycle of virus replication were used for immunoprecipitation with various sera from natural (Saimiri sciureus) and experimental (Saguinus nigricollis, Saguinus fuscicollis, Aotus trivirgatus, New Zealand White rabbits) hosts. The analysis of the precipitates separated in sodium dodecyl sulfate:polyacrylamide gels revealed that in tumor-developing animals a specific set of viral polypeptides were precipitated, which were not precipitated by sera obtained from the natural host Saimiri sciureus. Using labeled proteins from H. saimiri 11 and its attenuated strain, respectively, a difference was shown after precipitation with a serum raised against infected cell proteins of H. saimiri 11.

Animals↗
PubMed1983

[Effect of tyrosinase inhibitors on phenol oxidase (EC 1.14.18.1)].

Phenoloxidase is a specific enzyme for defence cells. It has been histochemically investigated, if substances partly known as tyrosinase inhibitors inhibit the phenoloxidase activity too. The tested substances are: thiourea, sodium-hydrogensulfate, cysteine, 2,3-dimercapto-propanol, N,N-dimethyl-p-phenylendiamine, glutathione, and ascorbic acid. It was detected for all substances, except dimethylphenylendiamine, an inhibitory effect. An attack at the enzyme molecule could be demonstrated for thiourea and dimercaptopropanol. The possibility of enzyme inhibition by these sulphur containing substances is of clinical interest.

Animals↗
PubMed1983

[Primarily malignant tumors of the renal pelvis and the ureter - clinical manifestations and results of radiotherapy].

Twenty-two own cases are presented in order to describe the clinical manifestations and therapy, especially the postoperative radiotherapy, in case of carcinomas of the upper urinary tract. The authors agree with literature to recommend a high voltage radiotherapy with 45 Gy to the regional lymph node groups and with 50 to 55 Gy to the former tumor region in case of all tumors with infiltrating growth, of demonstrated lymph node metastases and of subtotally removed primary tumors. Radiotherapy should become an essential part of the therapeutic conception for carcinomas of the renal pelvis and of the ureter because of the nearly complete absence of side effects and the small rate of local recurrences.

Adult↗
PubMed1983

[Further studies on modification of phenoloxidase by effectors].

With the aid of the histochemical phenoloxidase (PO) assay, 12 substances were tested. On the one side they can act as substrates or as inhibitors of phenoloxidase and on the other side as immunogenic or immunosuppressive compounds. In particular the following substances were investigated: o-cresol, Levamisol, prednisolonebisuccinate, Bleocin, siliciumdioxide, 4-methylbrenzcatechol, +-catechine, thiomersal, D-penicillamine, hydrochinonemonomethylether, hydrochinonemonoethylether, and hydrochinonemonobenzylether. No changes in the phenoloxidase activity and in the morphological behaviour of the cells could be detected using Levamisol, prednisolonebisuccinate, siliciumdioxide, and Bleomycin, indicating an immunogenic stimulation or immunosuppressive effect. 4-methylbrenzcatechol is probably transformed into a soluble reaction product by phenoloxidase. It could not clearly demonstrated by the histochemical method, if this substance is used as a true substrate. +-catechine, thiomersal, and D-penicillamine cause strong to complete enzyme inhibition of the phenoloxidase containing cells (POC), which are located in the spleen and gut of the white rat. Hydrochinonemonoethylether, hydrochinonemethylether, and hydrochinonemonobenzylether cause an increased pigment fermentation, but they are not used as substrates for the PO.

Adjuvants, Immunologic↗
PubMed1983

[Embolism caused by cardial myxoma].

Myxomas of the heart may present a systemic embolization before heart valve occlusion. A histological examination of peripheral emboli may result in the diagnosis. The tumour should be removed early before the occurrence of irreversible embolic complications. An embolic history could be found in 5 of our 8 cases. Two patients died immediately after complete peripheral arterial obstruction.

Adult↗
PubMed1983

[Clinical aspects and radiotherapy of stage III and IV neuroblastomas].

Contrary to other tumors in children, e.g. leukemia and Wilms tumor the prognosis of which has been considerably improved by the application of surgery, radiotherapy, and chemotherapy, the treatment results of one of the most frequent tumors, namely the neuroblastoma, have not essentially ameliorated during the last few years. The authors present 28 own case records of irradiated patients and describe the clinical symptoms, diagnosis and therapy, especially radiotherapy of the neuroblastoma. A prolongation of the survival time by several months could be achieved in a small group of eight patients treated additionally with an aggressive chemotherapy. The overall long-term prognosis, however, could not be improved hitherto.

Abdominal Neoplasms↗
PubMed1983

[Effectiveness of photofluorography screening studies in the early detection of bronchial carcinoma].

Report on results of a prospective study for earlier detection of peripheral and central bronchial carcinoma by fluorography performed for 6 years. In 1972 41,532 men of the age groups 1907 to 1937 were enrolled in the study group examined every 6 months. They were compared statistically and clinically to a control group of 102,348 persons of about the same sex and age distribution examined every two years by mass-x-ray. 1. By fluorographic screening the detection and resection rate in the study group was significantly increased. The percentage of resections was double as high as in the control group. 2. The higher detection rate especially in the younger age groups (40 to 54 years) of the study group caused an increase of the resection rate being three times higher than in the corresponding age group of the control population. 3. 67.5% of the persons with resection in the study group and 49.5% in the control group came to a life expectancy of more than three years. A 5 years healing after resection was attained by 23 of 42 resected patients of the study group and by 15 among 46 of the control group (55% to 32%). 4. Fluorography in 6 months intervals led to an increase of lower tumor stages. 5. At present fluorographic examinations showed to be the only mode of detection with good chances of resection as well in the study as in the control group, case-finding with clinical methods offering only small chances. 6. Among the patients resected in the study group the histological type of adenocarcinoma was rather frequent in 26.0%, parvicellular carcinoma amounting to 13.5%, on the other hand in the control group these types could be found with the same frequency in 16.8%. 7. The own results are reviewed with national and international investigations. Fluorographic examinations of selected risk groups (males between 40 and 70 years) in short intervals have proved to be at present the only method of finding bronchial carcinoma in time with some effectivity. 8. The effectivity of mass-x-ray-examinations must be improved a) by aimed examinations of risk groups, b) by improving the operational approach of fluorography using a special data bank of inhabitants, c) by reducing the medical protraction still high up to diagnosing bronchial cancer, d) by using the computer controlled risk aimed x-ray-examination for a complex screening programme.

Adult↗
PubMed1983

Survival time in cystinosis. A collaborative study.

In a retrospective study the overall survival time of 205 cystinotic patients of six countries was determined. The median survival time was 8.5 years. The median time for 'renal death' (age at death due to uraemia or age at starting renal replacement therapy) was 9.2 years. The youngest patient dying of renal death was 5.2 years. No sex difference in survival time was noticed. Furthermore no difference in survival time was noted between the different countries. The analysis of the overall survival curve indicates no clear differences between the infantile and adolescent types of cystinosis.

Adolescent↗
PubMed1982

Mouse interferons enhance the accumulation of a human HLA RNA and protein in transfected mouse and hamster cells.

A recombinant clone (pJY150R1.1) encoding the human major histocompatibility antigen (HLA-B7) was introduced into mouse cells and hamster cells by cotransformation with selectable genes. The exposure to mouse interferon of the cells transformed to HLA-B7+ resulted in a severalfold increase in the level of HLA antigen and RNA. The HLA-B7 clone used for the transfection includes a 670-base pair DNA sequence upstream from the coding segment. It remains to be established if the 670-base pair segment is necessary and/or sufficient to make the transcription of the HLA gene responsive to interferon.

Animals↗