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Biomedical subjects

F Stenbäck

Publications and source records attributed to F Stenbäck.

At least 109 records · Page 6Linked to original sources
PubMed1980

Surface ultrastructure of human endometrium. Effect of hormonal status and neoplastic progression.

The structure, size and number of uterine endometrial surface epithelial cells and specialized structures, cilia and microvilli were analyzed by light microscopy, transmission and scanning electron microscopy. The purpose was to further our understanding of the biological, morphological and prognostical implications of change in hormonal status and neoplastic progression. The results of this study showed that the quantitative and qualitative alterations followed a similar pattern: the cilia and microvilli were minimally developed in atrophic endometrium, and gradually progressed in size and number in relation to oped in atrophic endometrium, and gradually progressed in size and number in relation to the hormonal cycle and hyperplastic endometrium, unless associated with cellular atypia. Lesions with atypical adenomatous hyperplasia showed irregular and disorganized surface structure, progressively more apparent in specimens from adenocarcinomas. Decreasing degree of differentiation of the tumor and radiation treatment caused a reduction in number and size, as well as derangement in the structure of cilia and microvilli. The results showed the sensitivity of the uterine lining to hormonal changes, the distinction between different types of edometrial hyperplasia and the close interrelationship between atypical adenomatous hyperplasia and early adenocarcinoma, as well as the extent and severity of different clinical entities, including radiation treatment.

Adenocarcinoma↗
PubMed1980

Adnexal participation in formation of cutaneous tumors following topical application of 9,10-dimethyl-benzanthracene.

The response of the hair follicle apparatus to topical 9, 10-dimethyl-benzanthracene applications was studied in several strains of mice and rats. Early follicular destruction in mice was associated with subsequent formation of large number of epithelial tumors. Preserved follicular structures in rats proliferated with the formation of low incidence of adenomas and trichoepitheliomas. Hair nevi, hairfollicle nevi and trichofolliculomas, unrelated to treatment, were observed in several animal strains.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Skin carcinogenesis as a model system: observations on species, strain and tissue sensitivity to 7,12-dimethylbenz(a)anthracene with or without promotion from croton oil.

The pattern of development of tumours was studied in several mice strains, rabbits and pigs. Repeated carcinogen applications caused the appearance of numerous papillomas, keratoacanthomas and squamous cell carcinomas in Swiss, A, ASW/SN Balb/c and C57B1 mice, New Zealand and outbred laboratory rabbits. AKR mice were only little sensitive and Hormel mini pigs unresponsive. Initiation with 7,12-dimethylbenz(a)-anthracene and promotion with croton oil produced in Swiss, A, Balb/c and C3H mice as well as New Zealand rabbits a large number of squamous papillomas. Pigmented or adnexal tumours were not observed, and only a few dermal fibromas and fibrosarcomas.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Characteristics of neoplastic progression and tumor behavior in skin carcinogenesis by different methods: an experimental study.

Characteristics of chemically induced skin tumor formation by different methods were studied in 600 Swiss mice. A large dose of 9,10-dimethylbenz(a)anthracene (DMBA) alone or followed by 12-0-tetradecanoyl-phorbol-13-acetate(tpa) and a small dose of DMBA followed by TPA or DMBA repeatedly induced papillomas in 80--90% of the animals. Of these 44--65% regressed and 11--16% became malignant. Keratoacanthomas, observed mainly in repeated DMBA treated animals, were seen to arise de novo in 1--12% of the animals, or from papillomas, 3--12%, they became malignant in 4--9% of the animals. Squamous cell carcinomas were formed de novo in 1--8% of the animals or from papillomas or keratoacanthomas in 10--14% of the animals. Duration of experiment and degree of malignancy related to size of tumor and level of invasion. It is concluded that tumor formation is a stepwise process, with the different types of treatment affecting different aspects of tumor formation to a varying degree.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1980

Relation between clinical and autopsy diagnoses, especially as regards cancer.

The clinical diagnoses of 377 patients were compared with those derived from autopsy; the incidence, confirmation rate and detection rate were correlated to age, sex and duration of stay in the hospital. The diagnoses were in complete agreement in 75% of the cases; as regards location they differed in 20% and malignancy being unsuspected in 5% of the cases, where vascular diseases were the most frequent clinical findings. Lymphomas and leukemias were overrepresented in the study and had a high confirmation and detection rate, 97% resp. 94%. Tumours of the liver, gallbladder and pancreas were underrepresented and had a low detection rate, 37%, and confirmation rate, 59%. For other tumours the confirmation rate was higher, 84-97%, and detection rate lower, 72-80%. Similar antemortem and postmortem diagnoses were seen most commonly in young patients, regardless of sex and who stayed in the hospital for an extended period of time.

Adolescent↗
PubMed1979

Incubation of 3,4-benzo(s)pyrene with serum fractions: effect on tumor production.

The effect on tumor formation in Swiss mice of incubation of 3,4-Benzo(a)pyrene [B(a)P]either with saline or saline containing serum, gamma-globulin or albumin (form mouse or rabbit) was investigated. A high incidence of sarcomas (80--100%) was obtained in Swiss mice by B(A)P incubated in vitro with rabbit serum, rabbit gamma-globulin, mouse serum, mouse gamma-globulin, and saline. A lower incidence (60--65%) was obtained with B(a)P incubated with mouse serum, mouse albumin, and rabbit albumin. The data suggest that binding of B(a)P to protein, particularly to albumin, significantly decreases the biological activity of B(a)P.

Animals↗
PubMed1978

Tumor persistence and regression in skin carcinogenesis. An experimental study.

A lifetime study in Swiss mice showed that a single 300microgram application of 7, 12-dimethylbenzanthracene (DMBA) once, or 300 or 30microgram DMBA once followed by 3.2 microgram phorbolester for 15 weeks induced a high number of skin tumors many of which regressed spontaneously. The regression occurred mostly early in the experiment, the number of appearing and regressing tumors following a cynical pattern. The incidence of regressions was only to a limited extent associated with tumor size, tumor duration and total number of tumors. Repeated DMBA treatment, 5 microgram twice a week induced the same types of tumors in larger numbers: with a smaller incidence of regressions and only if they were transient in nature, i.e., lasting less than 3 weeks. These occurred in animals which showed a large number of persisting tumors simultaneously, but which rarely displayed multiple regressions. The results indicate the occurrence of multiple steps of neoplastic transformation from hyperplastic lesions, benign regressing tumors, presistent tumors and frankly malignant ones, the incidence as well as biological behavior depending upon inducing treatment.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Antibody stimulation of benzo(a)pyrene carcinogenesis.

Benzo(a)pyrene (BP) was conjugated to horse serum albumin (HSA) and then attached to aldehyde fixed human erythrocytes. These cells were used in a passive hemagglutination test to measure BP antibody. BP antibodies were found to be induced in Swiss mice injected with tumorigenic doses of BP. Of the mice treated with BP, those which developed tumors soonest had the highest levels of BP antibody. This observation suggested that the antibody to BP may stimulate tumor development. When rabbit antibody to BP was injected with BP a significantly increased tumor formation occurred. Active immunization using BP conjugated to a foreign protein also significantly increased tumor formation when the mice were treated with BP. Our findings suggest that the immune response to carcinogens is an important component of the carcinogenic process.

Animals↗
PubMed1978

Life history and histopathology of ultraviolet light-induced skin tumors.

The life history and histopathology of UV light-induced skin tumors were studied in NMR rats, outbred female Swiss mice, and Syrian golden hamsters. High intensity UV light of medium wavelengths produced hyperplasia and papillomas, as well as a dysplastic, intermediary solar keratosis-like stage, with distinct cellular atypia leading to several types of squamous cell carcinomas. High doses of UV irradiation of short duration caused scars, which developed into fibromas and fibrosarcomas composed of "light" and "dark" cells. Carcinomas with neoplastic squamous and fibrous components were uncommon; however, collision tumors with two components were occasionally seen. Angiomas and angiosarcomas with a proliferating endothelial structure were observed, but adnexal tumors, with follicular or sebaceous differentiation, and basal cell carcinomas were infrequent. Pigment cell tumors were found only rarely. The number of tumors and tumor-bearing animals at different stages of the experiment were also studied. Tumors were compared with lesions induced by chemical carcinogens in different systems. UV carcinogenesis was characterized by many tumor-bearing animals, but with a low total tumor count and a high mortality, thereby decreasing the number of animals-at-risk. The tumor types, their progression from on type to another, and the distribution of certain biologic characteristics were also analyzed. We concluded that UV irradiation is an effective tumor inducer in animal skin, and the type of tumor, its behavior, and location depend on the experimental conditions.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1978

Role of talc and benzo(a)pyrene in respiratory tumor formation. An experimental study.

Biologic and morphologic alterations caused by repeated intratracheal instillations of talc, alone or in combination with benzo(a)pyrene (B(a)P), were studied in Syrian golden hamsters to determine the possible carcinogenic and cocarcinogenic effects of talc. Talc alone failed to induce respiratory tumors, granulomas or mesothelial proliferation, but when a mixture of equal quantities of talc with B(a)P was administered, papillomas, squamous cells carcinomas and undifferentiated tumors of the larynx, trachea and lungs resulted. It therefore appears that in the hamster, talc is devoid of carcinogenic activity in itself, but does affect the activity of polycyclic hydrocarbons.

Adenocarcinoma↗
PubMed1977

Tumur induction by 7H-dibenzol[c,g] carbazole in the respiratory tract of Syrian hamsters.

The respiratory tract of male and female Syrian golden hamsters was treated intratracheally with 7H-dibenzo[c,g]carbazole (DBC), a tobacco smoke component. The carcinogen was given by multiple instillations at two dose levels. At the lower dose (9 mg), 35 of 46 hamsters (72%) developed respiratory tract tumors. The group receiving treatment at the higher dose level (30 mg) died earlier because of the toxicity of the compound. In this group, 15 of 45 animals (33%) had respiratory tract tumors. These occurred in the larynx, trachea, bronchi, and lungs, but predominated in the trachea and bronchi. Morphologically, most tumors were papillomas and squamous cell carcinomas. This study indicates the highly potent carcinogenic effect of DBC and that respiratory tumors can be induced in this model system without any carrier dust.

Animals↗
PubMed1977

Local and systemic effects of commonly used cutaneous agents: lifetime studies of 16 compounds in mice and rabbits.

A number of commonly used external agents were applied repeatedly on the skin of the mouse and rabbit. These chemicals, components of commercially available products included 4-hydroxyanisole, benzalkonium chloride, bromodeoxyuridine, iododeoxyuridine, 5-nitroacenaphthene, N-N-diethyltoluamide, hexachlorophene, para-aminobenzole acid, benzophenone, isopropylmyristate, pyrogallol, resorcinol and ethylhexanediol. Also tested were a commercial hairspray, a dandruff shampoo and an anti-dandruff agent. Local and systemic changes were studied and the tumour incidence compared with that of an effective carcinogen, 9,10-dimethylbenz(a)anthracene. The mice showed no local toxic changes or tumour formation and the systemic tumour incidence, i.e., tumours of the liver, lungs, lymphatic system and other organs, was similar to that of control animals. In rabbits, a number of proliferative, benign and malignant ear tumours were observed in the positive controls, thereby demonstrating the efficacy of this model. Local toxic changes were seen in benzalkonium- and hexachlorophene-treated animals, but no skin tumours. Four animals had uterine tumours. In addition, one lung and one kidney tumour, unrelated to the method of treatment, were seen.

Administration, Topical↗