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Biomedical subjects

J Müntzing

Publications and source records attributed to J Müntzing.

At least 37 records · Page 2Linked to original sources
PubMed1979

A rat prostatic adenocarcinoma as a model for the human disease.

A transplantable, metastasizing prostatic adenocarcinoma (Tumor I) in Lobund Wistar rats was examined for activity and distribution of five hydrolytic enzymes and for ability to accumulate radioactive zinc. The results suggest that the tumor had arisen in the ventral lobe of the prostate and that its growth was not affected by orchiectomy, adrenalectomy, or replacement treatment with exogenous androgen or corticosteroids. The androgen independency of the tumor was further shown by the low uptake of 3H-testosterone, in contrast to the high uptake in the ventral prostate. Tumor growth was retarded by Cytoxan but not by 5-fluorouracil, Estracyt, or streptozotocin, three agents clinically effective in the treatment of some patients with prostatic cancer resistant to endocrine therapy. It is concluded that this tumor in Lobund Wistar rats may be an adequate model for human prostatic cancers resistant to the agents mentioned above.

Acid Phosphatase↗
PubMed1979

Direct and indirect effects of docosanol (IK.2), the active principle in Tadenan, on the rat prostate.

To better understand the mode of action of Tadenan, a drug used in the treatment of benign prostatic hyperplasia, the effect of its active principle docosanol, IK.2, was investigated in rats. IK.2 had no effects on the weight and histologic appearance of the prostate in intact rats but increased the RNA/DNA quotient in the ventral prostate. The plasma concentrations of luteinizing hormone and testosterone were reduced. In orchiectomized animals IK.2 increased the weight of the prostate and the adrenals. In adrenalectomized, orchiectomized animals IK.2 did not increase prostatic weight but on the contrary caused a further weight reduction. IK.2 had a thymolytic effect in intact rats but not in adrenalectomized rats in which the thymus weight was increased. The results indicate that IK.2 increases adrenal steroid secretion. The supposedly higher concentration of adrenal androgens causes a stimulation of the prostate most easily discernible in orchiectomized animals. The further weight reduction of the ventral prostate in orchiectomized, adrenalectomized animals, and the increased thymus weight in adrenalectomized animals after IK.2 administration may suggest that IK.2 has effects other than the stimulatory effect on the adrenals.

Adrenalectomy↗
PubMed1978

Enzyme activity and distribution in rat prostatic adenocarcinoma.

The activity and distribution of acid phosphatase, alkaline phosphatase, nonspecific esterases, beta-glucuronidase, and aminopeptidase were examined in the transplantable R-3327 rat prostatic adenocarcinoma and compared with those in the four prostatic lobes of the rat. Both the well and poorly differentiated tumor cells in R-3327 carcinoma were characterized by high activities of beta-glucuronidase and aminopeptidase. The poorly differentiated cells had a high alkaline phosphatase activity. The enzymatic profile of the R-3327 adenocarcinoma closely resembled that of the anterior and dorsal prostate. The origin of the tumor in one of these prostatic lobes is probable, but not certain.

Adenocarcinoma↗
PubMed1978

Mammary tumour inhibition and subacute toxicity in rats of prednimustine and of its molecular components chlorambucil and prednisolone.

Prednimustine, a chlorambucil ester of pregnisolone, retarded growth of DMBA-induced mammary tumours in rats and reduced the number of tumours. A combination of chlorambucil and prednisolone (C + P) in the same proportion as in prednimustine, had similar effects, 8 and 26 mg per kg of the C + P combination being equipotnet to 16 and 64 mg per kg of prednimustine, respectively. The mortality figures suggested that prednimustine was considerably less toxic than equipotent doses of C + P. This toxicity difference was confirmed in a parallel investigation of the subacute toxicity in rats of prednimustine and C + P. This study showed that the mortality, reduction of lymphocytes and platelets, and bone marrow depression was much lower after pregnimustine than after equimolar amounts of the C + P combination. The results suggest that the low toxicity of prednimustine makes this drug a better cytostatic agent than the C + P combination treatment.

Animals↗
PubMed1977

Inhibitory effects of Estracyt on R-3327 rat prostatic carcinoma.

Estracyt (estramustine phosphate) injected intraperitoneally, 100 mg, per Kg. three days a week for four weeks, retarded growth of the R-3327 tumor in intact rats and in orchiectomized rats given androgen. The growth inhibition was accomplished by reduction of tumor deoxyribonucleic acid concentration and of the activities of acid phosphatase, leucine aminopeptidase, and other hydrolases. Histologic examination revealed cellular necrosis particularly prominent in the orchiectomized, androgen-treated rats. Estracyt did not affect the uptake of 65-Zn in the tumors but markedly reduced the high uptake in the dorsolateral prostate. There was no accumulation of 3H or 14C in the tumors after intravenous administration of 3H, 14C-labeled Estracyt, but the isotope concentrations decreased much in the same way as they decreased in the dorsolateral prostate. The isotopes were retained in the ventral prostate, where their concentrations were approximately twenty times higher than those in the muscle four hours after injection. The results demonstrate the value of the R-3327 tumor in the evaluation of drugs of potential clinical use for the treatment of prostatic cancer. The results also show that Estracyt has an antitumor effect which is not dependent on the antigonadotropic action of the drug.

Acid Phosphatase↗
PubMed1977

Hormonal control of zinc uptake and binding in the rat dorsolateral prostate.

The zinc uptake in the dorsolateral prostate of rats was studied after different hormonal manipulations. Orchiectomy reduced the uptake of 65Zn. Administration of estradiol benzoate to orchiectomized rats doubled the 65Zn uptake, a phenomenon which was not observed in orchiectomized-adrenalectomized rats. Adrenalectomy in orchiectomized rats had no effect on the concentration of radioactivity beyond the castration-induced decrease. A prolactin release inhibitor, 6-methyl-8-erogelenylacetamide, reduced the radioactivity concentration without changing the weight of the gland. Cyproterone acetate reduced the weight but not the radioactivity concentration. The concentration of 65Zn in the ventral prostate was not changed by orchiectomy, adrenalectomy, or the administration of estradiol benzoate, prolactin release inhibiors, or cyproterone acetate. The results suggest an important role for prolactin in the zinc uptake in the dorsolateral prostate but not in the ventral prostate.

Acetamides↗
PubMed1976

The growth characteristics of metastases from experimental renal tumors.

Wistar-Furth rats and BALB/c mice were implanted with tumor cells from metastases or primaries of an experimental Wilms' tumor or an experimental renal cell adenocarcinoma. The survival time, metastasis formation and growth of the primary tumor after implantation of metastatic tumor cells did not exceed those found after implantation of tumor cells from the tumor primaries. It is concluded that the higher growth rate usually found in metastases is not necessarily due to a selection of metastatic cells with a short cell growth cycle but that there are other environmental factors enhancing the growth of metastases.

Adenocarcinoma↗
PubMed1976

Histochemical and ultrastructural study of prostatic tissue from baboons treated with antiprostatic drugs.

Histochemical and ultrastructural investigation of the prostate in baboons treated parenterally with saline revealed that the epithelial cells in the caudal prostatic lobe possess very high acid phosphatase activity, moderate nonspecific esterase activity and alkaline phosphatase activity, and little or no amino-peptidase or beta-glucuronidase activity. Only a few lipofuscin granules were found. Ultrastructurally, the epithelial cells had a characteristic polar appearance with a supranuclear zone dominated by large secretory vacuoles. Secretory granules were abundant in the apical zone. No clear difference was found between the cranial and the caudal prostate except that the acid phosphatase activity of the epithelial cells was much lower in the former. In baboons treated with estraumustine phosphate, diethylstilbestrol diphosphate, or with flutamide, i.e., drugs used in the treatment of advanced prostatic carcinoma, the epithelial cells in the caudal prostatic lobe showed a varying degree of atrophy, which was least in the flutamide-treated animals. The histologic changes were accompanied by only minor changes in the enzyme activities, but the number of histochemically demonstrable lipofuscin granules were substantially increased, a finding confirmed by electron microscopy. The drugs did not notably affect the cranial prostate. The findings showed that the caudal, but not the cranial, lobe of the prostate of the baboon resembles the human prostate and can be affected by drugs known to have a desirable effect on the carcinomatous human prostate.

Acid Phosphatase↗
PubMed1976

The absorption metabolism, and excretion of Estracyt (NSC 89199) in patients with prostatic cancer.

Estraumustine phosphate (estradiol, 3-N-[bis(2-chloroethyl)-] carbamate-17beta-dihydrogenphosphate (Estracyt) labeled with 3H in the estradiol moiety and 14C in the carbamate moiety was synthesized, and its absorption, metabolism, and excretion were studied after oral administration to three patients with prostatic carcinoma. One of the patients was also given the same dose by intravenous injection. In addition to monitoring isotope levels in peripheral blood, urine, and feces, samples of portal vein blood were obtained through a catheter in the umbilical vein. Analyses of portal blood samples revealed that most of the estramustine phosphate was dephosphorylated to estramustine during absorption. Estramustine was found to be the major metabolite in peripheral blood after oral as well as after intravenous administration. The urinary excretion data appeared to warrent the conclusion that most of the carbamate ester of estraumustine is hydrolyzed before it is excreted. In the patient given estramustine phosphate by both routes the absorption of the compound when given by mouth was found to be approximately 75 per cent.

Administration, Oral↗
PubMed1975

Comparison and significance of respiration and glycolysis of prostatic tissue from various species.

The respiration and glycolysis of prostatic tissue from baboons, rhesus monkeys, dogs and rats were compared to the respiration and glycolysis in human prostatic tissue. All the primate prostates had a high glycolytic ability and a low respiration in contrast to the rat and dog prostate. Treatment of baboons with drugs clinically effective against prostatic cancer did not change the prostatic metabolism despite a marked prostatic atrophy. In vitro the drugs reduced respiration markedly. The metabolic similarity between the human and the baboon and rhesus monkey prostate indicates that nonhuman primates should be investigated in the evaluation of chemotherapeutic agents for treatment of prostatic cancer.

Animals↗
PubMed1975

Creatine phosphokinase in prostatic tissue.

A histochemical study of creatine phosphokinase (CPK) in the rat ventral prostate revealed that the epithelial cells had a high cytoplasmic activity which was retained or even increased when the cells were atrophic as a consequence of castration. Both the fibromuscular stroma, which is prominent in the ventral prostate of castrated rats, and the secretion had a high level of activity. In human benign prostatic tissue where CPK was present in the epithelium, secretion and stroma, pronounced differences in activity could sometimes be observed between the epithelium of adjacent acini and also between cells in the same acinus. There was no obvious correlation between CPK activity and degree of epithelial hyperplasia. The activity in carcinomatous prostatic epithelial cells varied considerably between specimen from different patients but was uniform within a given specimen in contrast to the variation of epithelial CPK activity within non-carcinomatous tissue. Thus, a difference in the pattern of CPK activity was observed between malignant and non-malignant epithelial cells.

Animals↗
PubMed1975

The prognostic value of acid phosphatase and beta-glucuronidase activity in biopsy specimens from patients with reactivated prostatic cancer.

The quotient between the activities of acid phosphatase and beta-glucuronidase in biopsy specimens of malignant prostatic tissue varied among 11 patients with reactivated, estrogen-resistant prostatic carcinoma. No correlation was found between the quotient and the therapeutic response to estramustine phosphate. In biopsy specimens obtained after 2 months' treatment, the quotient was lower in those patients who responded to the treatment. Thus, the quotient before treatment is of no prognostic use but diminution of the quotient found after treatment for 2 months is a sign of good clinical effect of the therapy.

Acid Phosphatase↗