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T Schramm

Publications and source records attributed to T Schramm.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Drugs from the classes of tricyclic antidepressives and antiepileptics, nitrosatable under simulated human gastric conditions].

The nitrosatability of Pryleugan (imipramine), Herphonal (trimipramine), and Finlepsin (carbamazepine) was investigated under simulated human gastric conditions using a colorimetric measuring method. All of them proved to be nitrosatable even at very low nitrite concentrations. In the presence of ascorbic acid, the formation of N-nitroso compounds under model conditions was inhibited markedly. N-nitroso-dihydrodibenzazepine and N-nitroso-dibenzazepine could be identified by thin layer chromatography as main products. The biological effects of these N-nitroso compounds are not known up to now.

Carbamazepine↗
PubMed1988

[Studies on dichlorvos (DDVP). II. Testing of dichlorvos for carcinogenic activity in rats].

The question has remained open, whether or not the pesticide Dichlorvos (DDVP) should be classified as a carcinogen. The results of a long-term experiment of testing DDVP in male and female C57Bl/6/Bln mice, recently published by us in this journal did not indicate the development of neoplastic lesions due to the administration of the compound. Now we report on results of long-term administration of DDVP to male and female BD IX/Bln rats. In the groups of male rats a increased incidence of proliferations of bile duct cells and of oval cells of the liver was observed, which was statistically significant (p less than 0.05) in the group of the higher dosed animals when compared with the group of the vehicle control male rats. Among the DDVP-treated female rats a significantly decreased incidence of tumors of the adrenal glands and of mammary tumors was observed as compared to the vehicle control group. Similar results were obtained in earlier experiments, when rats were treated with Trichlorfon, which easily convert to DDVP. In comparison to the corresponding control group DDVP-treated male rats showed a higher incidence of focal, hyperplasias of the urinary bladder, of focal hyperplasias of the pelvis and of transitional cell carcinomas of the renal pelvis. DDVP-treated female rats showed the opposite, namely lower incidences of these types of tumors, when compared with the control group. In our study on rats there were no neoplastic lesions found which could be attributed to the treatment of the animals with DDVP.

Animals↗
PubMed1988

Activated fos oncogene in rat embryo fibroblasts transformed by ras and myc oncogenes.

Rat embryo fibroblasts (REF) were transformed by simultaneous gene transfer of the complementary oncogenes ras and myc using the calcium phosphate coprecipitation method. Cell lines derived from transformation foci expressed in addition to ras and myc cellular oncogene fos while normal REF did not express ras, myc and fos according to the hybridization methods used. The transformed cell lines produced colonies in soft agar and tumors in newborn syngeneic rats. From one tumor a cell line was established which was characterized by a high level of fos gene expression.

Animals↗
PubMed1987

[Sonographic diagnosis of fetal liver cysts].

The authors report on prenatal ultrasonic diagnosis of foetal liver cysts with a massively thickened and cystic placenta in the twenty-third week of pregnancy. Karyotyping and serological examination of foetal blood samples of the umbilical vein gave normal results. The liver cysts were tapped twice subsequently, because they displaced other foetal abdominal and thoracic organs. In the thirty-fifth week of pregnancy the foetus died due to malnutrition resulting from the changes of the placenta, the origin of which remained unclear.

Adult↗
PubMed1987

[Chemoprevention of cancer--present status, problems and trends].

The most desirable way of eliminating the cancer incidence is by prevention. While the removal of causative agents is the primary goal of cancer prevention, for the foreseeable future it is likely to be incomplete. Therefore the development of a second line of cancer prevention based on chemoprevention assumes importance. During the past decade a growing number of naturally occurring and synthetic chemicals have been found which prevent or reduce the occurrence of cancer especially in experimental animals. These compounds belong to more than 20 different classes of chemicals. The mechanisms of action of most of them are up to now poorly understood. Classifying inhibitors of carcinogenesis according to the time during the carcinogenic process at which they are effective it is possible to divide them into 3 main categories: Substances that prevent the formation of carcinogens from precursors, blocking agents and suppressing agents. There are also several classes of chemicals that inhibit the phase of tumor promotion. But many anticarcinogens only act in combination with specific carcinogens or in distinct species, specific organs, tissues or situations, and completely different effects under other circumstances cannot be ruled out. In terms of application of the existing data to prevention of human cancer there has been a focus on 2 types of efforts: To select compounds that have little toxicity (i.e. ascorbic acid, beta-carotene), but which have not been shown to have broad inhibitory capacities, or to select compounds (i.e. retinoids) which have inhibitory efficacy but also can produce toxic side effects. When one evaluate a chemopreventive compound, considerations of its projected use are highly relevant. If the compound seems to be very potent but has significant toxicity, it may be useful for high-risk individuals but not for the general population.

Animals↗
PubMed1987

Transformation of rodent immortalized and embryo cells by oncogenes. II. Rat embryo fibroblasts (REF).

Rat embryo fibroblasts were transformed by co-transfer of two plasmids carrying the oncogenes ras and myc, respectively. In contrast to immortalized cells gene transfer of ras alone was not sufficient for transformation of rat embryo cells. Embryo cells transformed by both oncogenes showed an altered morphology and produced colonies in soft agar. Cell lines were established from transformation foci. These cells are characterized by a high proliferation capacity, they expressed the oncogenes ras and myc and produced regressing tumors in syngeneic newborn rats. Oncogene expression was demonstrated by in situ and blot hybridization. A cell line was established from a rat tumor induced by oncogene transformed cells. This cell line, designated FTD5, showed in addition to an increased expression of the transferred oncogenes ras and myc an elevated expression of the cellular oncogene fos.

Animals↗
PubMed1987

[Studies on dichlorvos (DDVP). I. Testing of dichlorvos for carcinogenic activity in mice].

Up to now the question remained open, whether or not the pesticide Dichlorvos, should be classified as a carcinogen. We report on our results of long-time oral administration to male and female C57B1/6/Bln-mice of Dichlorvos to test the compound for carcinogenic activity. Dichlorvos significantly increased the incidence of focal hyperplasias (transitional cell hyperplasias) of the urinary bladder in male and female mice and decreased significantly the incidence of mixed lymphomas in mice of both sexes as compared with control animals (treated with solvent or untreated). There were no neoplastic lesions found including papillomas of the urinary bladder which could be attributed to the treatment of the animals with Dichlorvos.

Administration, Oral↗
PubMed1986

[Ultrasonic diagnosis of a fetal lung cyst].

The authors report on prenatal sonographic diagnosis of a large congenital solitary bronchiogenic pulmonary cyst in the 21st week of pregnancy. The cyst became progressively smaller during the further pregnancy course. After delivery on term the bronchial cyst was removed by surgery. The infant has since developed without any abnormal findings.

Adult↗
PubMed1986

[Terminology of carcinogenesis in light of the current concepts of the mechanisms of action of chemical carcinogens].

The approaches to prepare a uniform and unified scientific terminology of chemical carcinogenesis are presented. The main definitions proposed (carcinogen, initiation, promotion, mutagen, multistage carcinogenesis, anti-carcinogen, cocarcinogen, carcinogenic risk, etc.) are based on the current state of comprehending mechanisms of the action of chemical carcinogens.

Animals↗
PubMed1985

[Sonographic diagnosis of fetal development disorders at the 1st Gynecologic Clinic of the Munich University 1984].

The diagnostic accuracy of sonographic screening is demonstrated by the results obtained in 171 pregnant women referred to the Department of Gynaecology of the University of Munich during 1984 for on-target sonography of foetal developmental disturbances. The accuracy was found to be 80%. Examination of pregnant women at risk shows a very low rate of developmental disturbances. The consequences arising from the observed disturbances of development are discussed.

Abortion, Induced↗
PubMed1985

[Etiology of colon cancer--current aspects].

Multiple factors such as tumour initiating, tumour promoting, tumour inhibiting are known to be involved in the aetiological process of most colon tumours. Dominant factors are associated with life style habits. Yet in spite of many experimental and epidemiological data it has not been possible, hitherto to give convincing recommendations for the primary prevention of this type of tumours.

Bile Acids and Salts↗