Search PubMed⌕ Search

Biomedical subjects

T Sanner

Publications and source records attributed to T Sanner.

At least 73 records · Page 4Linked to original sources
PubMed1985

Retinoids have different effects on morphological transformation and anchorage independent growth of Syrian hamster embryo cells.

The effect of different retinoids on morphological transformation and anchorage independent growth of Syrian hamster embryo cells has been studied. Retinoic acid and its derivatives were found to induce morphological transformation of hamster embryo cells, and to synergistically increase the transformation frequency when exposed in combination with benzo[a]pyrene. The increase was maintained when the cells were sequentially exposed to benzo[a]pyrene and retinoids in a similar way as observed for tumor promoting phorbol esters. At the same time retinoids were found to strongly decrease anchorage independent growth of a hamster embryo cell line. The present results support previous findings indicating that retinoids may have an enhancing effect on the early stages in carcinogenesis, and an inhibitory effect on the later stages.

Animals↗
PubMed1985

Comparative genotoxicity and nephrotoxicity studies of the two halogenated flame retardants tris(1,3-dichloro-2-propyl)phosphate and tris(2,3-dibromopropyl)phosphate.

Tris(1,3-dichloro-2-propyl)phosphate (Tris-CP) was metabolized to products which were mutagenic for Salmonella typhimurium TA100 in the presence of liver microsomes from phenobarbital (PB)-pretreated rats and NADPH. Effects of various inhibitors and inducers of cytochrome P-450 on Tris-CP mutagenicity were in accordance with PB-inducible forms of this enzyme system being responsible for the formation of mutagenic product(s). A comparison was made between the toxic potential of the two halogenated flame retardants Tris-CP and tris(2,3-dibromopropyl)phosphate (Tris-BP) in 5 in vitro tests. Tris-CP was much less potent than Tris-BP with respect to bacterial (Salmonella/microsome or Salmonella/hepatocyte assay) and mammalian (V79 cells) mutagenicity, as well as DNA repair synthesis in hepatocytes. On the other hand, Tris-CP and Tris-BP were both equally effective in transforming Syrian hamster embryo cells in vitro. Tris-CP was not nephrotoxic to rats after a single dose of 500 mg/kg intraperitoneally, whereas Tris-BP caused extensive tubular necrosis accompanied by elevated levels of plasma urea and creatinine.

Animals↗
PubMed1984

Short-term bioassays of fractionated emission samples from wood combustion.

Extracts of an emission sample from wood burning, consisting of particles and volatiles, have been fractionated on an HPLC silica gel column into five fractions of increasing polarity. Nonfractionated samples and the individual fractions have been tested in three different short-term bioassays: the Ames Salmonella assay, the sister chromatid exchange (SCE) induction-test in Chinese hamster ovary cells (CHO), and the cell transformation test on Syrian hamster embryo (SHE) cells. Most of the total activity was found in the volatile part of the sample with all three bioassays, whereas the particle extract had the highest activity per unit mass extracted. The second most polar fraction contained most of the mass and was also highly active in all assays. The most polar fraction was very potent in the Salmonella assay, but showed only a weak response in the eukaryotic bioassays. Storage of the samples for several months at 0 degrees C revealed that the bacterial mutagens present in the most polar fraction were labile; the mutagenicity was almost totally lost after 1 year's storage.

Animals↗
PubMed1983

Expression of transformed morphology and anchorage independent growth of hamster embryo cells.

Formation of morphologically transformed colonies and the ability to grow in semi-solid agar has been compared for 3 different cell lines from hamster embryo and for primary hamster embryo cells. By manipulating the growth conditions, transformed colony morphology and growth in agar could be induced for all cell types studied. Conditions that induced morphologically transformed colonies, also produced growing colonies in agar. One cell line and the primary cells needed the presence of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate for the expression of transformed morphology and agar growth, while the two other cell lines produced both morphologically transformed colonies and growth in soft agar without any additions. None of the cell lines would produce morphologically transformed colonies in the presence of newborn bovine serum. Likewise, the cells were dependent on fetal bovine serum in order to grow in soft agar, except for one of the cell lines which produced a low number of agar growing colonies in newborn bovine serum. The data indicate a close relation between morphological transformation and growth in soft agar.

Agar↗
PubMed1983

Early detection of breast cancer by leukocyte adherence inhibition assay.

The hematocytometer leukocyte adherence inhibition technique was used to study cell-mediated immune activity against breast carcinoma. In a group of 83 patients with untreated breast cancer in stage I, 74% showed a positive response, among 47 patients in stage II, 64% responded, while only 51% of the 37 patients in stages III and IV responded. Of 86 control persons, only two women showed a positive response. In a group of 296 women with benign breast disease, 21% showed a positive reaction against breast carcinoma antigen. The percentage of positive responses was higher than the average among women with risk factors such as: mother or sister with breast cancer, previous removal of benign breast lumps, microcalcifications, and increased intraductal epithelial proliferation found in the biopsies. Women with benign breast disease having two or more of the above risk factors were assigned to the high risk group. Of 49 women in this group, 47% had reactive leukocytes. Ninety-two women had only one risk factor, and 27% of those showed a positive reaction. Of the 155 women with none of the risk factors, only 10% had a positive reaction. The results suggest that leukocyte adherence inhibition test may be used to identify groups of women with an increased possibility of developing breast cancer.

Antigens, Neoplasm↗
PubMed1983

Assay for initiators and promoters of carcinogenesis based on attachment-independent survival of cells in aggregates.

A cell line (HRRT) derived from a hereditary renal rat tumor has been used in an assay for initiators and promoters of carcinogenesis based on attachment-independent survival in aggregates. Treatment with single noncytotoxic doses of the carcinogens urethan (1 mM), N-methyl-N-nitrosourea (30 microM), and benzo(a)pyrene (0.2 microM) for 1 hr did not affect survival of HRRT cells in the aggregate assay system. However, when carcinogen treatment was followed by exposure of the cells to the potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate (0.16 microM), a considerable increase in survival was observed. With urethan as an initiator, it was found that tumor promoters (12-O-tetradecanoylphorbol-13-acetate and phorbol-12, 13-didecanoate) induced a considerable response in the assay system, while nonpromoting phorbol esters (4-O-methyl-12-O-tetradecanoylphorbol-13-acetate and 4 alpha-phorbol-12, 13-didecanoate) did not affect the survival. Exposure of HRRT cells to NiSO4 (40 microM) for 3 hr did not influence cell survival in the aggregate form. However, subsequent treatment of the cells with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate induced a marked increase in the number of viable cells. Moreover, treatment of HRRT cells with a nontransforming dose of urethan (1 mM) for 1 hr followed by continuous exposure to nickel sulfate (40 microM) also increased cell survival in the aggregate form. These results support the view that nickel sulfate may act as both an initiator and a promoter in mammalian cell transformation. The present data also indicate that the aggregation assay system using the HRRT cell line may be a valuable in vitro screening assay for putative initiators and promoters of carcinogenesis.

Animals↗
PubMed1982

Leukocyte adherence inhibition assay in human pulmonary neoplasia.

The hemocytometer leukocyte adherence inhibition technique was used to study cell-mediated immuno-activity of patients with lung cancer. KCl extracts (3.5 M) from the lung cancer cell line Calu-1 and the breast cancer cell line MCF-7 were used as antigens. Of 138 patients with lung cancer, 85% showed a positive response against the Calu-1 antigen. The response was independent of the histological type of the tumor and was the same among untreated patients, patients undergoing different types of treatment and patients who died within 3 months after blood collection. Twenty-five percent of the untreated lung cancer patients also reacted against the breast cancer antigen. Among lung cancer patients undergoing different types of treatment, 36% reacted while 50% of the patients who died within 3 months after blood collection reacted against the breast cancer antigen.

Antigens, Neoplasm↗
PubMed1982

A serum immune factor in detection of an occupational group with increased risk for lung and nose cancer.

Epidemiological studies have demonstrated that workers in the nickel refinery industry have an increased risk for respiratory tract carcinoma. In the present study, serum from 51 workers at a Norwegian nickel refinery have been tested against lung, nasal and breast carcinoma antigens in the humoral leukocyte adherence inhibition test. The breast cancer antigen was used as a non-specific antigen. The frequency of positive response against the lung carcinoma antigen was significantly higher among the refinery workers (21/51) than in the controls (3/17) (P = 0.07). Moreover, among workers employed for 10 years or more, the response was higher than found for workers with shorter employment. Of the nickel workers with nasal dysplasia, 56% (15/27) gave a positive reaction against the lung carcinoma antigen compared to 25% (6/24) of the workers without dysplasia (P = 0.03). The same trends were also found for the nasal carcinoma antigen. The study gives further support for the usefulness of the humoral leukocyte adherence inhibition test in identification of individuals with an increased risk for developing cancer.

Adult↗
PubMed1982

Promotional effect of different phorbol esters on morphological transformation of hamster embryo cells.

Hamster embryo cells were sequentially exposed to benzo[a]pyrene (BaP) (3 days) and different phorbol esters (4 days). Compounds which have been shown to act as tumor promoters in mouse skin carcinogenesis, showed a promotion-like effect on the formation of morphologically transformed colonies, while non-promoting analogs did not enhance the transformation frequency. In experiments where the exposure sequence was reversed, i.e. 12-O-tetradecanoyl phorbol-13-acetate (TPA) in the first exposure period and BaP in the second period, no significant enhancement of the transformation frequency was observed. The exposure to a low concentration of BaP in the second exposure period following a higher concentration in the first period, resulted in a strong enhancement of the transformation frequency suggesting that BaP also acts as a promoter.

Animals↗
PubMed1982

Fibrinolytic activity and morphological transformation of hamster embryo cells.

Excretion of plasminogen activator from colonies of Syrian hamster embryo cells has been studied after sequential exposure of the cells to benzo[a]pyrene (3 days), and 12-O-tetradecanoyl-phorbol-13-acetate (3 days). The excretion of plasminogen activator was assayed using the fibrin/agarose overlay technique. The frequency of plasminogen activator-positive colonies was about two times higher for morphologically transformed colonies than for colonies with normal morphology growing on the same dish. Thus, 9% of the transformed colonies, compared to 4% of the colonies with normal morphology, gave clear zones of lysis in the fibrin/agarose overlay after 2 h of incubation. The frequency of plasminogen activator-positive colonies on untreated dishes was 2%. The addition of protease inhibitors strongly reduced the formation of clear zones of lysis, while they did not affect the frequency of morphologically transformed colonies. The data show that the expression of plasminogen activator is not an obligatory event in the process of morphological transformation.

Animals↗
PubMed1982

Evaluation of tumour promoters by the hamster embryo cell transformation assay.

Morphological transformation of hamster embryo cells has been used to study the effect of exposure to different combinations of compounds. Combined exposure to benzo[a]pyrene and cigarette smoke extract, to benzo[a]pyrene and nickel sulphate, and to cigarette smoke extract and nickel sulphate resulted in a synergistic increase in the formation of morphologically transformed colonies. This synergistic effect can be accounted for mainly by the finding that cigarette smoke extract and nickel sulphate promote or increase the number of transformed colonies following exposure to benzo[a]pyrene. Different tumour promoters and non-promoting analogues possess a potency for enhancing the transformation frequency similar to that of tumour promoters in experimental systems in vivo. Thus, our modification of the hamster embryo cell transformation assay may be a simple and quick method for studying modifiers of carcinogenesis.

Animals↗
PubMed1981

Metal salts as promoters of in vitro morphological transformation of hamster embryo cells initiated by benzo(a)pyrene.

The hamster embryo cell bioassay has been used to study the effect of metal salts on morphological transformation. A synergistic enhancement of the transformation frequency was found for the combined treatment with organic carcinogens [benzo(a)pyrene, N-hydroxy-2-acetylaminofluorene, and 4-nitroquinoline 1-oxide] and nickel sulfate, cadmium acetate, or potassium chromate. Chromic chloride and zinc chloride did not induce transformation themselves, and they had no effect on the transformation frequency when tested in combination with benzo(a)pyrene. The synergistic effect between benzo(a)pyrene and nickel sulfate or cadmium acetate was also apparent when the cells were treated sequentially with the chemicals. When the cells were first exposed to benzo(a)pyrene, both nickel sulfate and cadmium acetate showed a promotion-like effect similar to that obtained with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate. Moreover, when 12-O-tetradecanoylphorbol-13-acetate or benzo(a)pyrene were used as promoting agents, both nickel sulfate and cadmium acetate were able to initiate morphological transformation. The data suggest that the metal salts are more potent as promoters than they are as initiators. The present findings may be of importance in relation to carcinogenicity of metal compounds to humans.

Animals↗
PubMed1981

Humoral antitumor immune responses in patients with breast cancer measured with the leukocyte adherence inhibition technique.

A modification of the hemacytometer leukocyte adherence inhibition (LAI) test was described. In this modification, 0.25% serum from patients with breast cancer was added with the relevant antigen to the assay system with the use of trypsinized leukocytes from control persons as indicator cells. The modified assay measured a humoral immune response. In studies of patients with untreated breast cancer (stages I and II) with the use of a KCl extract from a breast carcinoma or from MCF-7 cells as antigens, the modified LAI test was found to be at least as sensitive as was the ordinary test. In a blind study on sera collected from patients with breast cancer 0.5-2 years before the LAI measurements and stored at -20 degrees C, 15 of 18 (83%) patients had a positive response. Whereas the ordinary LAI test is limited to the use of fresh blood, the present test can be performed with small amounts of serum that can be frozen and stored.

Antibodies, Neoplasm↗
PubMed1980

Synergistic effect on morphological transformation of hamster embryo cells by nickel sulphate and benz[a]pyrene.

Morphological transformation and induction of somatic mutation in the hamster embryo cell bioassay have been used to study whether the carcinogenicity of nickel is affected by polycyclic hydrocarbons. The transformation frequency was found to increase with increasing concentration of nickel sulphate, benz[a]pyrene (BP) and methylcholanthrene. In experiments with combinations of nickel sulphate and BP, the transformation frequencies used for all concentrations were higher than for compounds tested separately. The greatest enhancement was found using 5 micrograms/ml NiSO4 . 6H2O and 0.78 microgram/ml BP. The transformation frequency obtained with this combination was 10.7%, compared to 0.5% and 0.6% for the individual substances. No synergistic effect could be detected between nickel sulphate and methylcholanthrene (MC). In experiments measuring somatic mutation by selection for ouabain resistance, the mutation frequency was likewise found to be significantly higher than expected in mixtures of nickel sulphate and BP. The present demonstration of the synergistic effect between nickel sulphate and BP is of interest with the potentiating effect of cigarette smoking on development of lung cancer among nickel refinery workers.

Animals↗
PubMed1980

Potentiating effect of cigarette smoke extract on morphological transformation of hamster embryo cells by benzo[alpha]pyrene.

Morphological transformation in the hamster embryo cell bioassay has been used to study the possibility that carcinogenicity of benzo[alpha]pyrene (BP) is affected by cigarette smoke extract and whether smoke extract will promote transformations initiated by BP. The transformation frequency increases wth increasing concentrations of BP and smoke extract. In experiments with a combined treatment of BP and smoke extract, the transformation rates were higher than expected for all concentrations from experiments with the compounds tested separately. The greatest potentiating effect was found using 0.01 micrograms/ml BP and 1 microgram/ml smoke extract. The transformation frequency obtained with this combination was 4.3% compared to 1.4% and zero respectively for the individual substances. In experiments where cells were treated sequentially with BP (0.05 micrograms/ml) for 4 days followed by smoke extract (1 or 5 micrograms/ml) for the next 4 days, the transformation frequency was significantly higher than expected on the basis of the compounds tested separately. The demonstration of a synergistic effect between BP and cigarette smoke and the promotion-like effect of smoke extract on BP-initiated transformations of hamster embryo cells are of interest in relation to the higher frequency of lung cancer found in areas with high air pollution compared to rural areas.

Animals↗