Identification of novel principles of keratin filament network turnover in living cells.

It is generally assumed that turnover of the keratin filament system occurs by exchange of subunits along its entire length throughout the cytoplasm. We now present evidence that a circumscribed submembranous compartment is actually the main site for network replenishment. This conclusion is based on the following observations in living cells synthesizing fluorescent keratin polypeptides: 1) Small keratin granules originate in close proximity to the plasma membrane and move toward the cell center in a continuous motion while elongating into flexible rod-like fragments that fuse with each other and integrate into the peripheral KF network.

Epidermolysis bullosa simplex-type mutations alter the dynamics of the keratin cytoskeleton and reveal a contribution of actin to the transport of keratin subunits.

Dominant keratin mutations cause epidermolysis bullosa simplex by transforming keratin (K) filaments into aggregates. As a first step toward understanding the properties of mutant keratins in vivo, we stably transfected epithelial cells with an enhanced yellow fluorescent protein-tagged K14R125C mutant. K14R125C became localized as aggregates in the cell periphery and incorporated into perinuclear keratin filaments.

[Hormone replacement therapy, proliferation in the breast and risk of carcinoma].

Objective: The objective of the study was to investigate the changes of histopathological and immunohistochemical parameters of breast tissue among the HRT users.

Design: Prospective, pilot study.

Setting: Departments of Gynecology and Obstetrics, Pathology and Radiology of the 2nd Medical School, Charles University and the Teaching Hospital Motol, Praha 5, Czech Republic.

Light-induced resistance of the keratin network to the filament-disrupting tyrosine phosphatase inhibitor orthovanadate.

Epidermal keratinocytes respond to low-dose light irradiation by inducing signaling cascades that lead to long-term effects on gene transcription thereby protecting cells against damage. In contrast, little is known about immediate light-induced alterations of structural proteins. We have made the intriguing observation that light produces fundamental changes in the properties of the keratin filament system of cultured epidermoid A-431 cells.

[Invasive ductal carcinoma of the breast: study of the number of copies of the CCND1 gene and chromosome 11 using fluorescence in situ hybridization (FISH) in comparison with expression of cyclin D1 protein and estrogen receptors (ER alpha) with immunohistochemical detection].

Background: Overexpression of oncogenic proteins may be caused by gene amplifications. Cyclin D1 participates in regulation of the cell cycle. Relations between cyclin D1 expression and amplification of CCND1 gene encoding this protein in invasive duct breast carcinomas (IDC) are not fully elucidated.

[What can we expect of raloxifene in the treatment of postmenopausal osteoporosis--views of a gynecologist].

Objective: Evaluation of positive properties and side effects of raloxifene treatment with respect to its potential use as agent to improve women's health and quality of life in postmenopausal years.

Design: A review article.

Setting: Obstetrics and Gynaecology Department, Charles University 2nd Medical Faculty and Teaching Hospital Motol, Prague.

Induction of rapid and reversible cytokeratin filament network remodeling by inhibition of tyrosine phosphatases.

The cytokeratin filament network is intrinsically dynamic, continuously exchanging subunits over its entire surface, while conferring structural stability on epithelial cells. However, it is not known how cytokeratin filaments are remodeled in situations where the network is temporarily and spatially restricted. Using the tyrosine phosphatase inhibitor orthovanadate we observed rapid and reversible restructuring in living cells, which may provide the basis for such dynamics.

In vivo detection of cytokeratin filament network breakdown in cells treated with the phosphatase inhibitor okadaic acid.

We have previously described vulva carcinoma-derived A-431 subclone AK13-1, which stably expresses fluorescently labeled cytokeratin filaments (CKFs). Time-lapse fluorescence microscopy of these cells permits the continuous monitoring of the dynamics of the CKF cytoskeleton in vivo. To study mechanisms and principles of CKF disassembly as it occurs, e.

[The importance of hormone receptors in benign breast diseases].

Benign breast lesions are usually divided with regard to the proliferative activity into three categories. These lesions, depending on their histopathological characteristics and correlation with epidemiological studies differ as to the risk of breast cancer. 1.

[Hormonal treatment of non-malignant diseases of the breast].

The authors summarize possibilities of hormonal treatment of non-malignant diseases of the mammary gland. Attention is paid in particular to progestins (progesterone, derivatives of hydroxyprogesterone, derivatives of 19 nor-testosterone), their combination with estrogens (hormonal contraceptives, minipills) and hormonal substitution therapy, methods of chemoprevention of mammary cancer. In conjunction with the subject the authors mention also the possibility to use some other preparations (Danazol, Gonadotropin releasing hormones, tamoxifen etc.

A history of poliomyelitis in the Czech Republic--Part II.

The first large epidemic of poliomyelitis in (previous) Czechoslovakia was recorded in 1939. It affected only the western part of the state, Bohemia, with a relatively high morbidity and mortality, 25.42 and 2.

A history of poliomyelitis in the Czech Republic--Part I.

The incidence of poliomyelitis in the Czech Republic shows four epidemiologically different phases recorded during a lifetime of one human generation: endemicity (until 1938), epidemicity (1939 to 1956), repression (1957 to 1960) and elimination (1961 till now). The phase of the endemic incidence of poliomyelitis studied in this paper finished in 1938. Since 1919 when poliomyelitis notification was started, three waves of increasing though low mortality were observed: in 1926, 1932 and 1936 (0.