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Biomedical subjects

A Bukovský

Publications and source records attributed to A Bukovský.

At least 19 recordsLinked to original sources
PubMed1996

Is irregular regression of corpora lutea in climacteric women caused by age-induced alterations in the "tissue control system"?

PROBLEM: We have recently observed that the regression of corpora lutea (CL) in women during the reproductive period of life is accompanied by a diminution of Thy-1 differentiation protein release from vascular pericytes and an accumulation of T lymphocytes and activated macrophages among both degenerating granulosa lutein cells (GLC) and theca lutein cells. These data suggest that the immune system and other stromal factors, representing components of the "tissue control system," may play a role in regression of the CL. We investigated degenerating CL from climacteric women to address the possibility that the decline of immune functions with advancing age may result in incomplete regression of luteal tissue. This could contribute to the altered hormonal profiles and abnormal uterine bleeding that frequently occur during the climacteric. METHOD: Immunoperoxidase staining and image analysis were used to localize Thy-1 differentiation protein of vascular pericytes, cytokeratin staining of GLC, neural cell adhesion molecule expression by theca lutein cells, CD15 of neutrophils, CD4, CD14, CD68, and leukocyte common antigens of macrophages, and CD3 and CD8 determinants of T lymphocytes. We also investigated the expression of luteinizing hormone receptor (LH receptor) and mitogen activated protein kinases (MAP kinases) in luteal cells. Samples of regressing luteal tissue were obtained during the follicular phase from perimenopausal women (age 45-50) who exhibited prolonged or irregular cycles. For comparison, luteal tissues from women with regular cycles (age 29-45) and CL of pregnancy were also investigated. RESULTS: Corpora lutea of the climacteric women exhibited irregular regression of luteal tissue characterized by a lack of cytoplasmic vacuolization and nuclear pyknosis in GLC, and by a persistence of theca lutein cells exhibiting hyperplasia and adjacent theca externa layers. This was accompanied by a continuing release of Thy-1 differentiation protein from vascular pericytes. Persisting GLC lacked surface expression of macrophage markers (CD4, CD14, CD68 and leukocyte common antigen) as well as nuclear granules exhibiting CD15 of neutrophils, detected in regularly regressing GLC. In addition, such persisting GLC showed weak or no LH receptor expression, and retained the expression of cytokeratin. They also exhibited enhanced staining for MAP kinases. Strong cytoplasmic MAP kinase expression with occasional nuclear translocation was also detected in persisting theca lutein cells, indicating high metabolic activity of these cells. T lymphocytes, although occasionally present in luteal stroma within luteal convolutions, did not invade among persisting GLC and were virtually absent from layers of theca externa and theca lutein cells. CONCLUSIONS: These data indicate that the regressing CL in climacteric women may exhibit persistence of luteal cells, perhaps because of age-induced alterations of the immune system and other local stromal homeostatic mechanisms involved in the elimination of luteal cells. Persisting GLC and/or theca lutein cells may exhibit abnormal hormonal secretion that contributes to the alteration of target tissues, such as the endometrium, resulting in abnormal uterine bleeding, hyperplasia, and neoplasia.

Adult↗
PubMed1995

Quantitative evaluation of the cell cycle-related retinoblastoma protein and localization of Thy-1 differentiation protein and macrophages during follicular development and atresia, and in human corpora lutea.

Ovarian follicular development is dependent on growth and differentiation of the oocyte, as well as the granulosa and theca cell layers. The majority of primary follicles in the adult human ovary are not growing, and most antral follicles undergo atresia. The mechanisms regulating follicular growth and differentiation are poorly understood. Expression of key regulatory proteins in cells of certain follicles may be involved. We have studied the distribution of retinoblastoma protein (pRb), a key cell cycle regulator, in human follicles and CL by quantitative immunohistochemistry. Recent studies suggest that high nuclear concentrations of pRb are associated with the arrest of cell proliferation and the beginning of differentiation; during advanced differentiation of cells pRb is markedly depleted or absent. We also studied follicular distribution of Thy-1 differentiation protein, a morpho-regulatory molecule associated with cell differentiation, and the presence of macrophages. Macrophages have been shown to stimulate steroidogenesis in granulosa cells in vitro, and they are required for release of Thy-1 differentiation protein from vascular pericytes among granulosa cells in vivo. Our results indicate that oocytes in resting follicles exhibit pRb in the nucleoli. During initiation of follicular growth, the pRb expression first extends over the oocyte nuclei and then diminishes from both nuclei and nucleoli in preantral follicles. When the oocytes reach maximum size in small antral follicles, the pRb expression is reestablished in oocyte nucleoli. In differentiating granulosa and theca cell layers of preantral and small antral follicles, pRb expression is high, but it is low in growing large antral follicles. During CL development and regression, pRb expression in the nuclei of granulosa lutein cells first increases and then decreases. Follicular development is accompanied by the presence of Thy-1 differentiation protein and macrophages under the follicular basement membrane. In growing large antral follicles, during the mid-follicular phase, larger macrophages exhibit physical contacts with granulosa cells through the follicular basement membrane, and, during the late follicular phase, small dendritic macrophages can be detected among granulosa cells, but not within the follicular antrum. Large antral follicles undergoing atresia exhibit strong pRb expression in granulosa cells. This is accompanied by a lack of Thy-1 differentiation protein among granulosa cells and the occurrence of large phagocytic macrophages in the follicular antrum. This is the first report of pRb expression in the human ovary.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Cycle↗
PubMed1995

Is corpus luteum regression an immune-mediated event? Localization of immune system components and luteinizing hormone receptor in human corpora lutea.

Factors determining the life span of the human corpus luteum (CL) are not known. In addition to being determined by hormonal factors, such as hCG, the life of luteal cells may be determined by the preservation of luteal vascularization. Furthermore, the CL represents an immunologically unique tissue, as it is formed after menarche, long after adaptation of the immune system toward self. Thus, CL regression may be immunologically mediated. To determine what role the vasculature and immune system play in human CL development and regression, we examined immunohistochemically 1) the expression of Thy-1 differentiation protein by vascular pericytes, 2) the expression of major histocompatibility complex (MHC) class I and class II molecules in granulosa lutein cells (GLC), and 3) infiltration of the CL by macrophages and T lymphocytes. LH receptor (LHR) and cytokeratin 18 expression were also studied. In developing CL, the pericytes of luteal microvasculature released Thy-1 differentiation protein among the endothelial cells of proliferating vessels. In mature CL, Thy-1 released from vascular pericytes accumulated on the surface of GLC, and these cells exhibited LHR immunoreactivity (LHRI). Overall LHRI increased during the luteal phase and was strongest at the beginning of the late luteal phase. Although vascular pericytes showed strong LHRI, no staining of endothelium was detected during the luteal phase. GLC exhibited strong cytokeratin staining and moderate staining for MHC class I and MHC class II antigens; numerous macrophages were detected in luteal tissue. During pregnancy, the staining pattern was similar to that seen in the mature CL at the end of the midluteal phase. During the late luteal phase, surface expression of MHC class I and MHC class II antigens by GLC was substantially enhanced, and some T cells invaded among luteal cells. By the end of the cycle, an acute regression of vasculature and luteal tissue was observed along the fibrous septa. The remaining GLC showed only surface and no cytoplasmic LHRI. During the subsequent cycle, in the presence of numerous T cells, regressing GLC exhibited strong surface expression of various macrophage markers, such as CD4, CD14, CD68, and leukocyte common antigen, a feature not detected in the CL during the luteal phase nor described in other tissues. A complete loss of cytokeratin staining in GLC was observed. In regressing CL, strong LHRI was present in the endothelium of small and large luteal vessels. In conclusion, vascular pericytes and macrophages may stimulate the development and senescence of luteal tissue. The senescence of GLC may be inconsistent with preservation of luteal vasculature, and T lymphocytes appear to participate in terminal regression of the CL. Regression of luteal tissue therefore resembles immunologic rejection of a transplant. During pregnancy, the aging process of GLC appears to be interrupted, possibly due to the temporary acceptance of the CL "graft."

Adult↗
PubMed1995

Immunohistochemical studies of the adult human ovary: possible contribution of immune and epithelial factors to folliculogenesis.

PROBLEM: Formation of primordial follicles in adult ovaries could be a cryptic process limited to relatively small areas of the ovarian cortex and occurring during a certain stage of the menstrual cycle. Such an event may require a specific milieu provided by factors involved in developmental processes, i.e., morphoregulatory molecules and macrophages. METHOD: Adult human ovaries were investigated by immunohistochemistry for surface epithelium and granulosa cell markers (cytokeratin 18 and MHC class I), immune system-related morphoregulatory molecules (Thy-1 glycoprotein and N-CAM), and macrophage phenotypes (CD14, CD68, and MHC class II). RESULTS: In some ovaries 300-500 microns areas of surface epithelium were overgrown by tunica albuginea, descended into the stroma, and apparently fragmented into individual small (20-40 microns) follicle-like cell nests. Differentiation of the surface epithelium was accompanied by macrophages and Thy-1 glycoprotein. Small segments of surface epithelium showed N-CAM and a lacked MHC class I expression. In such segments, clear spherical germ-like cells migrated into the deeper stroma, associated with the microvasculature, and eventually aggregated with follicle-like cell nests. CONCLUSIONS: Our data suggest that surface epithelium may be involved in the formation of some primordial follicles in adult ovaries. This process, and further follicular fate, may require a precise interplay of immune system related morphoregulatory molecules and macrophages.

Adult↗
PubMed1993

Cellular localization of luteinizing hormone receptor immunoreactivity in the ovaries of immature, gonadotropin-primed and normal cycling rats.

In this study we used two monoclonal antibodies against purified LH receptor (LHR) to localize and quantify LHR in ovarian compartments during follicular development, using gonads from immature, gonadotropin-primed, and normal cycling rats. In early preantral follicles, LHR immunoreactivity (LHRI) was identified in vascular endothelium and subsequently appeared in vascular pericytes. In healthy small antral (200-550-microns) follicles, LHRI continued to be present in thecal pericytes, but not in cells of the theca interna. However, in small antral follicles undergoing atresia, a dramatic decrease in thecal vessel LHRI with a concomitant increase in LHRI in hypertrophied theca was observed. In healthy antral follicles, LHRI of thecal cells was not observed until the cells reached medium (550-microns) size. High LHRI was occasionally observed in macrophage-like cells adjacent to the oocyte of large preantral follicles and among granulosa layers of medium-sized antral follicles. In the membrana granulosa, LHRI first appeared in cumulus cells of medium-sized antral follicles and subsequently spread to the entire granulosa cell population of large (750 microns) antral follicles. Treatment of immature rats with eCG markedly enhanced LHRI in theca and granulosa cells of all antral follicles, while eCG/hCG-treated (pseudopregnant) rats showed lack of LHRI in follicles and interstitial glands, but not in corpora lutea (CL). Within degenerating CL in the cycling ovary, compared to fresh and mature CL, a significant decrease occurred in intracellular LHRI. Our observations indicate that 1) vascular pericytes may play a role in follicular development; 2) LHR expression in granulosa may require an interaction of macrophages, oocytes, and cumulus cells; and 3) thecal hypertrophy accompanied by enhanced LHR expression occurs on follicles undergoing atresia.

Aging↗
PubMed1991

Cell-mediated and neural control of morphostasis.

Morphostasis refers to the maintenance of the differentiated state of tissues in an adult individual and it represents a basal event of homeostasis and the organism's existence. Most of the cells in the body are arrested in their differentiation at a certain point related to their optimal function. Evidence is rapidly accumulating on the general role of immunoglobulin-gene superfamily (IGSF) domains in the non-immune control of behavior of cells in various tissues. A novel 'tissue control system' (TCS) has been suggested, supporting the differentiation of tissue cells in an adult organism and functioning via the IGSF domains and cell-mediated control of morphostasis. We assume here that the morphostasis is established epigenetically during the early adaptive period. With its termination, coinciding with the attainment of an organism's immunocompetence, the combination of cell surface markers of the most mature cells in tissues are encoded in the TCS as the stop-signal (SS). This stage of tissue differentiation is maintained during further life: upon recognition of SS the committed TCS element does not stimulate further differentiation of the cell, i.e. it exhibits a stop-effect (SE). Each tissue-specific cell line has only one or no SE established depending on its presence or absence during development, respectively. The only way to escape an established SE and continue in differentiation is to change at least a portion of the SS. Hormones might act here directly, by conformation of their cell surface receptors recognized as a portion of SS, or indirectly, by influencing proteosynthesis of cell surface markers.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Experimental ablation nephropathy. Fine structure, morphometry, cell membrane epitopes, glomerular polyanion and effect of subsequent transplantation.

The subtotal (5/6) nephrectomy performed in 23 adult female rats induced severe hypertrophy of residual parenchyma with interstitial fibrosis, tubular dilatation, and focal and segmental glomerulosclerosis (FSG). This ablation nephropathy (AbN) caused proteinuria, progressive renal failure, and hypertension. The extent of FSG was assessed by semiquantitative scoring. The ultrastructure revealed widespread foot process fusion, many dense cytoplasmic inclusions in podocytes, and degenerative changes or disruption of mesangium with glomerular "microcysts". Numerous granular deposits of rat Ig were seen in the glomeruli but a short praeterminal i.v. load by heat-aggregated human Ig did not alter the morphology of AbN and produced discrete and inconstant glomerular deposits. Similarly an i.v. injection of protamine and heparin generated protamine-heparin complexes seen in various layers of glomerular capillary wall, similar to those found previously in normal rats. AbN displayed a partial irregular depletion of polyanion sites reactive with polyethylenimine in lamina rara externa. A significant increase in both glomerular and interstitial Ia+ cells and a marked predominance of W3/25+ cells in the interstitial infiltrates were documented by immunohistochemistry in the remnant kidneys. Both AbN and FSG could be largely corrected (or prevented?) by subsequent syngeneic renal transplantation (TPL; 6 animals). On the other hand a severe AbN was found in two post-ablation residues after unsuccessful TPL with graft necrosis or sclerosis.--AbN has some analogies to various chronic human nephropathies (e.g. FSG) and may explain their progression to the terminal failure. Degenerative and finally destructive mesangial lesion seems to be of prime importance in AbN.

Animals↗
PubMed1989

Monoclonal antibodies against human leucocyte antigens. III. Antibodies against CD45R, CD6, CD44 and two newly described broadly expressed glycoproteins MEM-53 and MEM-102.

Monoclonal antibodies against several human leucocyte cell surface antigens were prepared and characterized: (1) MEM-56, MEM-93, MEM-66, and MEM-104 against the CD45R antigen (220 kDa and 205 kDa mol. wt. forms of the leucocyte common antigen CD45 expressed on B-lymphocytes, myeloid cells and a subpopulation of T-lymphocytes); (2) MEM-98 and MEM-100 against the T-lymphocyte antigen CD6 (mol. wt. 100 kDa); (3) MEM-85 against the broadly expressed antigen CD44 (mol. wt. 85 kDa) which was recently shown by us to be identical with the lymphocyte homing receptor; (4) MEM-53 against a newly described broadly expressed antigen of 35-40 kDa mol. wt. and (5) MEM-102 against another newly described glycoprotein of 40 kDa mol. wt. anchored in membrane through a phosphatidylinositol moiety.

Animals↗
PubMed1989

[Peritoneal macrophages and their activity in sterile patients with endometriosis].

The authors analyzed the peritoneal fluid (PF) during laparoscopic examination in 50 sterile women, incl. 27 where endometriosis was found. The control group was formed by 23 sterile women without signs of endometriosis. In both groups the volume of PF, concentration and absolute number of peritoneal macrophages and their phagocytic activity were evaluated. In the group of sterile women with endometriosis there was significantly increased volume of PF, higher concentration and absolute number of macrophages than in the group of patients without endometriosis. The phagocytic activity of peritoneal macrophages did not differ significantly in the control group and in patients with endometriosis.

Adult↗