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Biomedical subjects

F Stenbäck

Publications and source records attributed to F Stenbäck.

At least 91 records · Page 5Linked to original sources
PubMed1985

Initiation and promotion in young and old animals. Implications for human tumour formation.

The significance of ageing in experimental skin carcinogenesis and on the manifestation of tumour formation in man was studied. Initiation with the carcinogenic hydrocarbon 7,12-dimethylbenz [a]anthracene and promotion with croton oil in mouse skin showed that tumour formation was unchanged when promotion was delayed 3, 10, 23 or 43 weeks in comparison with that in untreated animals of the same age. The sensitivity to carcinogen treatment of animals over 71 weeks of age was less than that of animals 11-51 weeks of age; this finding affected the interpretation of data on animal groups treated 63 weeks after the start of the experiment. In a human autopsy study, the tumour incidence increased with age to the eighth decade; benign tumours of types not related to malignant tumours occurred in older age groups. The percentage of epithelial tumours was higher in humans aged 60-80 and in organs exposed to environmental agents, but lower in humans aged 80 and more.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1985

Basement membranes in ultraviolet light-induced skin lesions and tumors.

Basement membrane changes in human skin exposed to UV irradiation were studied by light and electron microscopy and antibodies to human collagen IV and laminin were compared to similar lesions in non-sun-exposed areas. A distinct basement membrane was seen in cases of epidermal solar keratosis, even with marked dysplasia and Bowenoid type lesions, and also around most of squamous cell carcinomas which showed basement membrane irregularities, thickening and reduplication. The invading edges of the squamous cell carcinomas with inflammatory infiltrates were devoid of laminin and collagen. Basement membrane disruption was also observed in lichen planus-type solar keratosis with severe inflammation, but with no evidence of malignancy. Alterations in basement membrane structure and location were associated with cutaneous morphological abnormalities not due to UV irradiation as such.

Basement Membrane↗
PubMed1984

Adenocarcinoma metastatic to the uterine cervix.

In this study 208 patients with adenocarcinoma of the uterine cervix were examined for the occurrence of tumors metastatic to this location. A total of 45 secondary tumors were found, 31 with a primary endometrial tumor, 6 with an ovarian serous or mucinous adenocarcinoma, 2 tubal tumors, 5 colonic adenocarcinomas, and 1 primary mammary tumor. Clinical and morphological aspects were studied, indicating the need for consideration of metastatic tumors as explanation for suspected neoplastic cervical lesions.

Adenocarcinoma↗
PubMed1983

Surface characteristics of adenocarcinoma of the uterine cervix.

The purpose of this study was to analyze the development and classification of cervical adenocarcinoma as seen by scanning electron microscopy (SEM) and correlate the result to morphological alterations in cervical squamous cell carcinoma and endometrial adenocarcinoma. The results showed the endocervical area to be covered by a single layer of columnar cells, some with cilia, containing numerous folds and clefts, but no real glandular structures. The surface of malignant tumors consisted of pavelike arrangements of grooves and clefts covered with blunt microvillous processes, shorter and less delicate than those found on normal columnar cells. The surface microridges of squamous cells were replaced by irregular projections in squamous malignancy and endometrial adenocarcinoma showed a more undulating endometrial appearance.

Adenocarcinoma↗
PubMed1983

Histological and ultrastructural pattern of cervical squamous cell carcinoma in a young woman.

A rare type of cervical squamous cell carcinoma with pseudoglandular features occurred in a 22-year-old woman. Histological and ultrastructural characteristics of this tumor with keratinized cells as well as glandular mucin containing structures and intracellular luminal formations are presented. The problems associated with the diagnosis of cervical carcinoma in young women are discussed.

Adult↗
PubMed1983

Clinical significance of estrogen and progestin receptors in ovarian cancer.

Concentrations of cytosol estrogen and progestin receptors were determined in ovarian carcinoma samples from 84 patients with early (stages I to II; N = 17), advanced (III to IV; N = 39), recurrent epithelial (N = 9), and nonepithelial (N = 5) cancer and with ovarian metastases of other malignancies (N = 11). Seventy-one percent of all the specimens contained estrogen and progestin receptors (3 or more and 6 or more fmol/mg cytosol protein, respectively, receptor-positive group), whereas 10% of the tumors were receptor-negative. Primary epithelial ovarian carcinomas were more often receptor-positive (81% versus 44%), and they had higher receptor concentrations than recurrent epithelial ovarian tumors. Primary endometrioid and serous carcinomas had higher concentrations of cytosol estrogen receptors than did mucinous tumors. Anaplastic endometrioid malignancies had significantly lower concentrations of both receptors than the differentiated tumors, whereas in serous carcinomas only cytosol progestin receptor displayed this difference. Patients with advanced malignancy characterized by low estrogen and/or progestin receptor concentrations had nonremovable tumor more often, and they survived for a shorter time than the other patients.

Adult↗
PubMed1982

Screening of asymptomatic postmenopausal women for gynecological malignancies, with special reference to endometrial sampling methods.

To investigate the applicability of cytological and histological endometrial sampling methods and to study the incidence of silent premalignant or malignant gynecological diseases during the postmenopausal years, 415 asymptomatic women were examined both clinically and with cytological smears and 360 of them also examined with jet wash or pistolet aspiration and Vabra curettage. Examination with jet wash, pistolet aspiration and Vabra curettage was possible in 57.2%, 83.1% and 76.1% of the cases, respectively. The cytological specimens (jet wash, pistolet) and the Vabra curettage specimens were inadequate in 3.7% and 44.5% of cases, respectively. Our study revealed two malignant (one mammary and one gastric cancer with ovarian metastases), seven premalignant (four endometrial and three cervical) and 55 benign gynecological or mammary lesions, amounting to 15.4% of the 415 women. These results, with only four severe endometrial lesions, indicate the restriction of endometrial screening examinations to only well-defined high risk women. Of the methods used, the pistolet aspiration is the most recommendable due to its applicability, patient acceptance, diagnostic reliability and the low incidence of unsatisfactory samples.

Adult↗
PubMed1982

Morphological characteristics of different types of cystic teratoma of the ovary. A study of surface ultrastructure in relation to tumor classification and development.

In this study the surface ultrastructure of 28 cystic ovarian teratomas was examined to determine their morphological appearance and the relation to biological behavior. The squamous epithelium of cystic tumors showed abnormal maturation and keratinization of surface cells with keratinous flakes occasionally in polypoid configurations. The respiratory epithelium showed an abundance of microvillous and ciliated cells, areas with disorganized surface structures were also seen. Piling up of squamous cells in heaps, piles, cauliflower- or onion-like arrangements were seen in lesions histologically regular. This study showed a distinct difference in surface ultrastructure as compared to ovarian cystadenomas emphasizing the difference in development. Surface ultrastructural studies also were useful in deciding the nature of histologically indeterminable lesions as well as in revealing areas of malignant potential.

Cilia↗
PubMed1982

Adenocarcinoma of the uterine endometrium. Surface ultrastructure as an indicator of malignant potential and effect of treatment.

In this study the surface ultrastructural changes of uterine adenocarcinomas of varying differentiation were compared to histological and clinical findings and the effect of radiation and hormone treatment analyzed. The results showed a close correlation between number, distribution and development of microvilli and cilia and degree of differentiation of the tumor: the cells of the anaplastic lesions were covered by sparse pleomorphic microvilli and ciliated cells were absent. Radiation therapy caused tissue destruction, necrosis and inflammation while progestin therapy caused an increase in the number of pleomorphic microvilli. Cell size and shape were also closely related to underlying morphological changes indicating the extent of neoplastic transformation and the effect of treatment. It is concluded that SEM analysis is a valuable adjunct to conventional techniques but not a diagnostic tool as such.

Adenocarcinoma↗
PubMed1982

Surface ultrastructure of epidermal proliferative lesions and atypias in relation to development of malignancy.

The significance of surface ultrastructural changes as indicators of neoplastic transformation and malignant progression in carcinogen induced experimental lesions in mice and premalignant and malignant lesions in man was studied by scanning electron microscopy (SEM) and correlated with transmission electron microscopy (TEM), light microscopy and biological behavior. The results showed the interfollicular epidermis consisted of polygonal cells in a cobblestone pattern, with regular microridges and grooves. Hyperplastic benign lesions in animals developed into papillomas reflected in proliferation and piling up of cells with surface scales and microvillous-like formations. In dysplastic states with malignant potential, solar keratoses, the smooth surface of the angular irregular cells reflected cytological abnormalities in the underlying epidermal cells. It was concluded that the surface ultrastructure reflects the biological behavior of epidermal cells indicating the development and structure of these lesions not obtainable by other methods.

Animals↗
PubMed1981

Benign, borderline and malignant serous cystadenomas of the ovary. A transmission and scanning electron microscopical study.

In this study benign, malignant and borderline types of ovarian cystadenomas were studied by different morphological, transmission electron microscopical and scanning electron microscopical methods. The main cell type, the tubal cell, contained numerous microvilli projecting into the lumen, some cells also possessed cilia in addition to microvilli. Infrequently endometrial like cells were found with branched cilia intermixed with microvillous projections similar to that of the endometrium. Endocervical-like cells, very uncommon, evidenced numerous cytoplasmic projections extending into the lumen, arranged in a wavelike pattern. The surface structures were well developed in benign tumors, in borderline tumors focal denuded areas with histologically atypias were seen and in malignant ones the surface cells were devoid of specialised structures. The results also support a metaplastic origin from ovarian surface epithelium for these tumors.

Cilia↗
PubMed1981

Initiation and promotion at different ages and doses in 2200 mice. I. Methods, and the apparent persistence of initiated cells.

Delay between initiation and promotion on mouse skin was in 1949 reported by Berenblum and Shubik not to affect tumour yields, and this led to the important concept of the irreversibility of initiation and stimulated the development of multistage models. Subsequent reports have, however, suggested that delay does decrease tumour yields, and this is confirmed by the present study of 2200 mice initiated at 8, 48, or 68 weeks with 10, 30, 100, or 300 microgram of DMBA and promoted by a standard dose of TPA for 15 weeks, after various delays. However, our data suggest that the decrease in tumour yields is chiefly or wholly due to a reduction, among ageing mice, of the ability to respond to promoters, and not to any substantial loss of initiated cells, for late initiation with immediate promotion also yielded a less rapid response than early initiation with immediate promotion. Interpretation of all such studies is complicated by the few weeks that the skin needs to repair ulceration and other damage induced by the higher doses of DMBA, for if promotion with TPA begins before such repair is complete the tumour yield may be misleadingly increased.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Initiation and promotion at different ages and doses in 2200 mice. II. Decrease in promotion by TPA with ageing.

Using the data described in Paper I, we compare the effects of the same treatment timings and doses given at different ages. Initiation with DMBA at 68 weeks of age, followed 3 weeks later by TPA, has a significantly (P less than 0.0001) less rapid effect on subsequent tumour incidence than does initiation at 8 or at 48 weeks of age, followed 3 weeks later by TPA. We suggested that this is chiefly due not to changes in the numbers of cells initiated by DMBA, but rather to a decrease in the promotional efficacy of TPA in ageing mice.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Initiation and promotion at different ages and doses in 2200 mice. III. Linear extrapolation from high doses may underestimate low-dose tumour risks.

The dose-response relationships from the data described in Paper I were analysed. Among unpromoted animals, only doses sufficient to cause ulceration with subsequent promotion due to wound healing caused a rapid crop of tumours, so the dose-response curve exhibited strong upward curvature. Among promoted animals, the response of the skin to initiation appeared to have been nearly saturated by all DMBA doses tested, so that a 30-fold decrease in dose produced only a 3-fold decrease in effect. The dose-response relationship thus exhibited strong downward curvature. Among promoted animals, estimation of the risks associated with very low doses of carcinogen by linear extrapolation through the origin from the effects of larger doses (which is often assumed to be conservative) would under-estimate the true risks by 10-fold or more. Our results emphasize that whereas linear interpolation from the results of high doses may be reasonable for data on the effects of continuous treatment with non-toxic dose levels of carcinogen, it may be misleading when extrapolating, as here, from the effects of single large doses.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1981

Development and classification of parovarian cysts. An ultrastructural study.

In this study the scanning and transmission electron microscopical features of parovarian cysts were analyzed to further the determination of histogenesis, development, classification and differential diagnosis of these lesions. Paramesonephric type lesions showed ciliated and microvillous cells, sometimes in a wavy arrangement with grooves and holes, similar to the oviduct epithelium. The mesonephric type consisted of an epithelium of tightly arranged angular cells with minimally developed surface structures. Destruction of specialized surface structures was frequently seen, epithelial proliferation was uncommon.

Female↗
PubMed1981

Endometrioid ovarian tumors: morphology and relation to other endometrial conditions.

Ovarian adenocarcinomas of endometrioid type were studied by different histological and histochemical technics to determine their morphologic criteria, the development of these tumors as well as their relationship to different conditions of the endometrium. Mucin secretion was evident as was cellular polymorphism on the ultrastructural level. Surface analysis revealed an endometrium-like pattern with cells showing cilia as well as numerous microvilli, different from that of other ovarian epithelial surface tumors. Ovarian endometrial lesions showed pattern as well as occasional derangement of surface structures in histologically regular epithelium.

Adenocarcinoma↗
PubMed1980

Morphology of ovarian mucinous cystadenoma: surface ultrastructure, development and biologic behavior.

Thirty mucinous cystadenomas, borderline tumors and cystadenocarcinomas were analyzed by scanning and transmission electron microscopy. Results were compared to those obtained by light microscopy. Benign tumors consisted of endocervical-type columnar, mucus-containing cells with microvilli and cilia, goblet cells and intestinal-type microvillous cells. Borderline tumors showed a decrease in number and size of specialized surface structures in relation to degree of cellular atypia, the number of nucleoli and nuclear indentations indicating areas of incipient malignancy. Invasive carcinomas consisted mainly of intestinal-like surface cells varying in size and shape in relation to degree of tumor differentiation.

Cystadenoma↗