Biomedical subjects

H Bojar

Publications and source records attributed to H Bojar.

59 records · Page 4Linked to original sources

PubMedDate not supplied

Differentiated DNA analysis in relation to steroid receptor status, grading, and staging in human breast cancer.

Flow cytometric DNA analysis was performed in 100 cases of human breast cancer. Using a category system of six ploidy groups, ploidy status was distributed as follows: The majority of the neoplasias were either diploid (45%), hyperdiploid (21%), or tetraploid (15%), whereas the remaining marginal ploidy groups, i.e. hypodiploid (4%), hypertetraploid (9%), and multiploid (6%) were less frequent. In an attempt to evaluate the prognostic significance of DNA content, ploidy status was correlated with steroid hormone receptor status, histopathological grade, and TNM data. The higher incidence of negative estrogen and progestin receptor status and higher histopathological grade in hyperdiploid malignancies was significantly different from the prognostically more favorable positive receptor status and lower grade in diploid tumors. Tetraploid neoplasias statistically resembled the latter group with respect to both parameters. As far as TNM data are concerned, tendencies towards less favorable staging were observed in hyperdiploid as compared to diploid and tetraploid tumors. A definite statement of the prognostic significance of the marginal ploidy groups cannot be made at present. In order to characterize diploid malignancies more closely, proliferative activity expressed by %S-phase was analyzed. Steroid receptor status of diploid tumors exhibiting more than 6% S-phase did not differ statistically from that of hyperdiploid neoplasias. In contrast, diploid tumors expressing less than 6% S-phase closely resembled tetraploid ones. Our data emphasize the prognostic significance of differentiated DNA analysis.

Breast Neoplasms↗

PubMedDate not supplied

Dexamethasone, medroxyprogesterone acetate, and vindesine modulation of human malignant melanoma growth in soft agar.

We have previously shown biopsies from human malignant melanoma, as well as a cell line (MELUR) derived from human malignant melanoma cells, to contain dexamethasone (DEX) - and medroxyprogesterone acetate (MPA) - binding macromolecules exhibiting properties of glucocorticoid receptors from well-known target organs. In this paper, we demonstrate that the cloning efficiency of MELUR melanoma cells is inhibited by DEX and MPA in a dose-dependent manner. MELUR tumour colony-forming units (MELUR-TCFU) were inhibited more than 40% by either DEX or MPA at 1 X 10(-7) mol/l with concentrations needed to obtain a 50% reduction in TCFU counts for both hormones of 3 X 10(-9) mol/l. MELUR cell growth in soft agar was also modulated by vindesine (VI). At 50 ng/ml, VI produced a 70% reduction of colony formation. The combined drug effects of either DEX or MPA and VI on colony formation were additive. The data indicate that the proliferative activity of MELUR cells is regulated by DEX and MPA, both acting additively to VI.

Antineoplastic Combined Chemotherapy Protocols↗

PubMedDate not supplied

Steroid receptor pattern of human colorectal neoplasms.

Twenty-four colorectal carcinomas were assayed for estrogen and progestin receptors by sucrose gradient centrifugation. Most biopsies were either completely estrogen receptor negative or displayed low titers of specific estrogen binding. Only three tumors demonstrated moderate estrogen binding activity (10-18 fmol/mg cytosol protein). In four tumors specific progestin binding exceeded 20 fmol/mg protein. Only a minor subset of the binders sedimented at 8S. Twenty-one colorectal tumors examined for the presence of glucocorticoid receptors were found to be receptor positive, without exception. Biopsies from normal colorectal mucosa displayed minute quantities of specific 8S estrogen and progestin binding, but significant titers of specific glucocorticoid binding. Our findings support the hypothesis that estrogens and progestins are unlikely to play a major role in endocrine control of colorectal neoplasms. The role of glucocorticoids in growth control of colorectal neoplasms remains to be defined.

Aged↗

PubMedDate not supplied

Gradient centrifugation analysis of steroid-hormone binding in human malignant melanoma.

Vertical tube rotor sucrose gradient centrifugation in the presence of the protease inhibitor sodium molybdate provide to give a deeper insight into the steroid hormone receptor status of human malignant melanoma (MM) as did previous studies using dextran-coated charcoal procedure only. As compared to endocrine dependent breast cancer, the oestrogen binding capacity of MM is low. Although in some biopsies fairly high concentrations of progestin binders were detected, the sedimentation properties were not receptor typic. Androgen binding was found to be negligible. In contrast, the presence of glucocorticoid receptors is a common feature of human MM. A human MM cell line was demonstrated to contain glucocorticoid receptors only.

Adult↗

PubMedDate not supplied

Grading system for breast cancer.

As recurrence rates in breast cancer depend significantly on degree of malignancy (6-9) and mitotic rates as part of the grading system are difficult to assess in exact manner, we widened the grading system by evaluation of the proliferative compartment to get more information about proliferation activity as an important factor for tumor-progression (15, 16). This additional analysis can be used as a control factor for the correctness of the evaluation of mitotic activity. We practice this procedure at present as a "working formulation". New antibodies are in preparation which allow to exclude the highly variable G1-Phase. Further precision and control of degree of malignancy can be achieved by photometric analysis of S-Phase, 5c exceeding rate and state of ploidy according to Auer scheme.

Adult↗