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R S Fritsch

Publications and source records attributed to R S Fritsch.

27 records · Page 2Linked to original sources
PubMed1980

[Stereologic studies on the mechanism of action of two 1,2-substituted 5-bis-(beta-chlorethyl)aminobenzimidazole derivatives].

The effects of two 1,2-substituted 5-bis-(beta-chloroethyl)-amino-benzimidazole derivatives on the course of phagocytosis in murine peritoneal macrophages after intraperitoneal injection of bovine fibrin has been investigated by means of quantitative ultrastructural stereologic methods. One of the compounds, IMET 3164, is a strong immunosuppressive agent with membrane-stabilizing effects while the other one, IMET 3393 (Cytostasan) is an effective cytostatic drug with weak immunological effects. From the results the following conclusions can be drawn. After stimulation by intraperitoneal injection of fibrin, macrophages of untreated animals show a rapid antigen uptake and digestion as well as a formation of new lysosomes. Simultaneously, an immigration into the peritoneal cavity of monocytes and an emigration of strongly storing macrophages takes place. After treatment with either benzimidazole-N-mustard derivative, most pronounced after IMET 3164, a delayed antigen phagocytosis and digestion and an inhibition of formation of new lysosomes can be observed. Likewise, the intraperitoneal cell fluctuation is strongly reduced after IMET 3164. The findings lend support to the hypothesis that immunosuppression may be induced, among other mechanisms, by an inhibition of phagocytosis and antigen processing by means of membrane-stabilizing compounds.

Animals↗
PubMed1979

Quantitative stereological studies on the mechanism of immunosuppressive effect of nitrogen mustards of benzimidazole derivatives: the role of polymorphonuclear leukocytes and mononuclear phagocytes.

The effect on antigen uptake and digestion in macrophages and polymorphonuclear leukocytes (PMNL) of 2 compounds of a series of benzimidazole nitrogen mustard derivatives has been investigated by ultrastructural quantitative stereological techniques in order to enlighten some mechanisms of the immunosuppressive effect of especially one of the chemicals. One compound, ZIMET 3393 (Cytostasan), is a powerful cancerostatic with only moderate immunosuppressive side effects while ZIMET 3164 proved an effective immunosuppressant with low cytostatic action. Results of a recent study (FRITSCH and GOTHE 1979) have lent support to the hypothesis that immunosuppression can be induced by an inhibition of antigen processing by macrophages through a membrane-stabilizing effect of the chemicals under investigation. It can be shown in the present study that in the case of ZIMET 3164 an increased competitive antigen phagocytosis and digestion takes place in PMNL. This alternative pathway of antigen processing is suggested to be ineffective with respect to enhancement of immune responses compared with that through macrophages, thus providing an additional possible mechanism of chemical immunosuppression.

Animals↗
PubMedDate not supplied

Value of the cytologic analysis of fine needle aspiration biopsy specimens in the diagnosis of pancreatic carcinomas.

Between 1982 and 1986, 410 preoperative percutaneous fine needle aspiration (FNA) biopsies of the pancreas were performed on 316 patients clinically suspected of having a malignant pancreatic tumor. Of 58 patients with pancreatic carcinomas subsequently confirmed by histologic investigation, the FNA biopsy yielded a cytologically positive diagnosis of carcinoma in 39 cases (67.2%) and suspicious findings in another 5 cases (8.6%). In 14 cases of malignancy (24.1%), the FNA puncture failed to sample material from the tumor; hence, the cytologic evaluation yielded false-negative results. Of 21 patients with inflammatory disorders of the pancreas, cytologically suspicious cells were observed in 5 cases (23.8%); in none of those 5 cases did the histologic examination show any evidence of carcinoma. This indicates that caution should be taken not to cytologically over-diagnose cases of pancreatitis. On the whole, cytology proved to be a valuable method for the diagnosis of pancreatic carcinoma; it provided the highest rate of positive results in comparison with other modern clinical diagnostic methods. Furthermore, cytology may improve the diagnostic results even in those cases with clinically negative or merely suspicious findings. FNA punctures of the pancreas produced no serious complications in this series.

Biopsy, Needle↗