Biomedical subjects

F Sinowatz

Publications and source records attributed to F Sinowatz.

At least 55 records · Page 3Linked to original sources

PubMed1998

Expression of growth hormone receptor in the bovine mammary gland during prenatal development.

Growth hormone (GH) is known to play a key role in postnatal growth and differentiation. The role of GH and its receptor (GHR) in prenatal development, however, is still controversial. Using reverse transcription polymerase chain reaction (RT-PCR), in situ hybridization (ISH) and immunohistochemistry we demonstrated the presence of GHR mRNA and protein in bovine mammary glands during fetal development. RT-PCR revealed GHR transcripts in fetal mammary glands from the third to the ninth month of pregnancy. By non-radioactive ISH, GHR mRNA was localized in the glandular epithelium, the surrounding mesenchymal cells, endothelial cells of vessels and in the stratum basale of the epidermis of fetal mammary glands. From the sixth month of fetal life onwards, GHR transcripts were also found in the cytoplasm of adipocytes. Immunohistochemical studies using the monoclonal antibody mAb 263 revealed the same distribution pattern as the mRNA. Our results imply that the growth hormone receptor is distinctly expressed in the immature mammary gland, suggesting that GH is involved in growth and differentiation of the fetal mammary gland.

Animals↗

PubMed1998

Localization of the zona glycoproteins ZPB (ZP3 alpha) and ZPC (ZP3 beta) in the bovine ovary during pre- and postnatal development.

The purpose of this study was to investigate the expression of two zona pellucida gene families ZPB (ZP3 alpha) and ZPC (ZP3 beta). Sections of ovaries from bovine fetuses, calves and cows were labelled with polyclonal antibodies. Immunopositive labelling was found in both the follicle cells and the oocyte. Labelling was dependent on the stage of development. The specific sequence of immunopositive reactions suggests that in the bovine fetus both the ovary and the follicle cells contribute to the production of the zona pellucida during pre- and postnatal development.

Aging↗

PubMed1998

Developmental changes in the expression of the growth hormone receptor messenger ribonucleic acid and protein in the bovine ovary.

By reverse transcription-polymerase chain reaction, the transcript of the growth hormone receptor (GHR) was demonstrated in oocytes, follicular cells, and corpus luteum of the bovine ovary. Immunoblotting using the monoclonal antibody mAb 263 resulted in a distinct protein band at 120 kDa, confirming that translation of the mRNA takes place in the same cells. Nonradioactive in situ hybridization revealed that distribution of the mRNA encoding GHR was correlated with the developmental stage of the follicle. Whereas in primordial and primary follicles the oocyte showed distinct amounts of the transcript encoding GHR, in tertiary follicles the mRNA was predominantly localized in the cells of the cumulus oophorus. GHR mRNA was also expressed in the large granulosa lutein cells, in the germinal epithelium, and in the endothelial cells of ovarian vessels. Colocalization of the GHR protein showed a distribution pattern identical to that of the mRNA. In calves, oocyte and follicle cells changed GHR expression in the same way as in the adult ovary. During embryonic development of the ovary, distinct amounts of the mRNA encoding GHR were found in primordial follicles shortly before birth. Our results imply that the GHR is involved in ovarian ontogenesis, especially in early folliculogenesis.

Animals↗

PubMed1998

Immunohistochemical localization of the spermadhesin AWN-1 in the equine male genital tract.

Spermadhesins are proteins with various functions in sperm capacitation and zona pellucida binding. In this study the cellular localization of the spermadhesin AWN-1 has been examined in the equine male genital tract. Results obtained by immunohistochemical methods reveal that in the horse AWN-1 is synthesized in spermatogonia, in the rete testis, the ductus epididymidis and the seminal vesicles. These findings indicate that the cellular origin of spermadhesins is species-specific.

Animals↗

PubMed1998

Protein-carbohydrate interactions during fertilization.

Interaction between gametes during fertilization is at least in part regulated by carbohydrate moieties of the zona pellucida (ZP) and carbohydrate binding proteins of the sperm surface. This review focuses on the protein-carbohydrate interactions during the primary binding of the sperm to the ZP in different species. Synthesis, structure and composition of the ZP are summarized. The functional significance of carbohydrate residues of the ZP as sperm receptor is discussed. Sperm surface proteins known to have specific ZP and carbohydrate-binding sites including the mouse beta1, 4-galactosyltransferase and sp56, the rabbit protein Sp17, a human mannose-binding protein and several members of the spermadhesin family are presented.

Acrosome Reaction↗

PubMed1998

Glycobiology of the olfactory system.

The olfactory system is a highly plastic region of the nervous system. Continuous remodeling of neuronal circuits in the olfactory bulb takes place throughout life as a result of constant turnover of primary sensory olfactory neurons in the periphery. Glycoconjugates are very important in olfactory development, regeneration and function. This article deals with different aspects of glycobiology relevant for the olfactory system. Various anatomical, developmental and functional subdivisions of the olfactory system have been labeled with exogenous lectins. The application of reverse lectin histochemistry resulted in the visualization of endogenous lectins, involved in fasciculation of olfactory axons. Numerous glycoproteins, among them members of the immunoglobulin superfamily, the cadherins and integrins as well as different glycolipids and proteoglycans can act as surface adhesion molecules in the olfactory system. The olfactory-specific form of the sialoglycoprotein neural cell adhesion molecule is implicated in olfactory neuronal and axonal guidance. Glycoconjugates including laminin, fibronectin and proteoglycans are abundant components of the olfactory extracellular matrix, influencing neurite outgrowth and cellular migration. Immunohistochemical labeling has revealed occurrence of the carbohydrate differentiation antigen, playing a role in neurulation and morphogenesis of the very early olfactory system. The synaptic vesicle glycoprotein, appearing also early in olfactory development, is used as a marker of olfactory tumors. Finally, membrane and transmembrane glycoconjugates as well as secreted glycoconjugates may act as olfactory receptor molecules.

Animals↗

PubMed1998

Expression and localization of members of the fibroblast growth factor family in the bovine mammary gland.

The goal of the study was to examine the expression and localization of members of the fibroblast growth factor family in the bovine mammary gland during different developmental and functional stages. Mammary tissue was obtained from German Brown Swiss cows (n = 23) during defined stages of mammogenesis (before and during pregnancy), lactogenesis, peak and late lactation, and involution. Extracted mRNA was analyzed by reverse transcription polymerase chain reaction and RNase protection assay. The tissue content of fibroblast growth factor-1 and fibroblast growth factor-2 was determined by radioimmunoassay, and the localization of fibroblast growth factor-2 was determined by immunohistochemistry. The highest mRNA concentration for fibroblast growth factor-1, -2, and -7 and their receptors was detected in the glands of virgin heifers or primigravid heifers during involution; less abundant fibroblast growth factor mRNA was detected during lactogenesis and galactopoiesis. Tissue protein concentrations of fibroblast growth factor-1 and fibroblast growth factor-2 showed similar tendencies. Immunoreactive fibroblast growth factor-2 was observed during mammogenesis and involution in endothelial cells, ductal epithelial cells, myoepithelial cells, and some alveolar cells. After positive staining, fibroblast growth factor-2 could only be observed in endothelial and myoepithelial cells during lactogenesis and could only be observed in myoepithelial cells during galactopoiesis. Expression, tissue concentration, and distinct localization suggest that fibroblast growth factors may be important in the local regulation of the bovine mammary gland.

Animals↗

PubMed1997

Differential expression of the growth hormone receptor and its transcript in bovine uterus and placenta.

By reverse transcription-polymerase chain reaction (RT-PCR) the transcript of the growth hormone receptor (GHR) was proved in bovine placentae of different gestational stages. Using non-radioactive in situ hybridization (ISH) the mRNA encoding GHR was localized in the uterine epithelium, glands, vessels and amniochorion of the placenta from the sixth week until the ninth month of gestation. Production of mRNA was low during the first trimester, significantly increased in the second trimester and peaked at the end of the sixth month of pregnancy. No transcript of GHR was found in the endometrium of non-pregnant uteri. The colocalization of the protein using a monoclonal antibody showed the same distribution pattern as the mRNA. Immunoblotting revealed a protein with a molecular weight of 120 kDa in the endometrium of pregnant cows which was not found in non-pregnant uteri. Our results imply that growth hormone is involved in placental metabolism and embryonic development from the early beginning of pregnancy until birth.

Animals↗

PubMed1997

Subpopulations of stromal cells from long-term human bone marrow cultures: ontogeny of progenitor cells and expression of growth hormone receptors.

Long-term culture of bone marrow derived stromal colony forming cells (S-CFC) in matrix and nutrient defined agar medium resulted in stromal cell colonies that pass sequentially through three distinct morphological stages: firstly, aggregated loose syncytium of round to avoid cells (stage I), a second developmental stage of large branching colonies in which the cells become enlarged, elongated with cytoplasmic projections forming a loosely anastomized network with adjacent cells (stage II), and finally cells become dissociated, loosing their long, thin cytoplasmic filaments and breaking their contacts with one another, but remain large and retain a bi-polar nature (stage III). Cells were also grown in liquid medium in a culture microenvironment closely resembling conditions of haemopoiesis in vitro. Using a panel of well defined monoclonal antibodies reactive against the rat, rabbit and human growth hormone receptors, this study found immunochemical evidence of the presence and localization of binding sites of growth hormone (GH) in the cell membrane and extra-nuclear Golgi area of long-term bone marrow derived human stromal cells in liquid and semi-solid nutrient agar mediums. GH-receptor immunoreactivity was present in small proliferating progenitor cells, myofibroblast-like cells, large reticular fibroblast cells, adipocytes and endothelial cells. Only MAb known to be reactive against human tissue resulted in strong immunoreactivity. The expression of GH-receptors not only on small proliferating, but also on the well differentiated cells, indicates a role for growth hormone on non-progenitor cells. GH-receptor immunoreactivity on differentiating and/or differentiated cells suggests that GH is also necessary for, or has a trophic function in differentiation. We propose that direct GH action is necessary not only for differentiation of progenitor cells as implied by the dual effector hypothesis, but also their subsequent clonal expansion, differentiation and maintenance.

Animals↗

PubMed1997

Expression of transforming growth factors alpha and beta-1 messenger RNA in the bovine mammary gland during different stages of development and lactation.

It is now widely accepted that the mammary gland is under interconnected hormonal and local control. Growth factors are involved in the intercellular signalling of the gland. Our aim was the detection of transforming growth factors alpha (TGF-alpha) and beta 1 (TGF-beta 1) messenger RNA during mammogenesis, lactogenesis, galactopoiesis and involution in the bovine mammary gland (total n = 27). During these stages the RNA was assessed by means of ribonuclease protection assay and reverse transcription-polymerase chain reaction (RT-PCR). To study possible influences of oestrogen, progesterone and prolactin on growth factor expression, mammary RNA was obtained from heifers after induced mammogenesis and lactogenesis, with and without additional prolactin inhibition (total n = 20). Very low levels of TGF-alpha and TGF-beta 1 expression were detected during lactogenesis and galactopoiesis, increasing levels during mammogenesis of primigravid heifers, and highest levels during mammogenesis of virgin heifers and during involution. TGF-alpha expression after induced mammogenesis was greater than after induced lactogenesis or physiological mammogenesis during pregnancy. Furthermore, TGF-alpha mRNA contents increased after prolactin inhibition. TGF-beta 1 expression was almost equal after induced mammogenesis and lactogenesis, but greater than during the physiological mammogenesis and lactogenesis. In conclusion, it can be assumed that growth promoting TGF-alpha and growth inhibiting TGF-beta 1 are co-expressed in the bovine mammary gland. Higher mRNA contents of both factors during mammogenesis and involution may indicate autocrine or paracrine functions for these growth factors during proliferation and reorganisation of the mammary tissue.

Animals↗

PubMed1997

Quantitation and histochemical localization of galectin-1 and galectin-1-reactive glycoconjugates in fetal development of bovine organs.

The display of cellular oligosaccharide chains is known to undergo marked developmental changes, as monitored histochemically with plant lectins. In conjunction with endogenous lectins respective ligand structures may have a functional role during fetal development. The assumption of a recognitive, functionally productive interplay prompts the study of the expression of a tissue lectin and of lectin-reactive glycoconjugates concomitantly. Focusing on common beta-galactosides as constituents of oligosaccharide chains and the predominant member of the family of galectins in mammals, namely galectin-1, the question therefore is addressed as to whether expression of lectin and lectin-reactive glycoconjugates exhibits alterations, assessed in three morphologically defined fetal stages and in adult bovine organs. Using a sandwich ELISA, the level of the rather ubiquitous galectin-1 is mostly increased in adult organs relative to respective fetal stages, except for the case of kidney. This developmental course is seen rather seldom, when the amounts of lectin-reactive glycoproteins or glycolipids are quantitated in solid-phase assays after tissue homogenization. Western blotting, combined with probing by labeled galectin-1, discloses primarily quantitative changes in the reactivity of individual glycoproteins. Performing the same assays on extract aliquots with a plant agglutinin, namely the galactoside-binding mistletoe lectin, whose fine specificity is different from galectin-1, its reduced extent of binding in solid-phase assays and the disparate profile of lectin-reactive glycoproteins reveal a non-uniform developmental alteration within the group of structural variants of beta-galactosides. Although sample preparation can affect ligand preservation and/or presentation and thus restricts the comparability of biochemical and histochemical results, especially for soluble reactants, the histochemical studies on frozen and paraffin-embedded sections of bovine heart, kidney and liver demonstrate that the localization of the galectin and of lectin-reactive epitopes can show a similar distribution, as seen in liver and heart, with organ-typical quantitative changes of a rather similar staining profile (heart, kidney) or notable changes in the spatial distribution (liver) in the course of development. This report emphasizes the potential value of combined monitoring of the lectin and its potential in vivo ligands to contribute to eventually unravel organ-related function(s) of a tissue lectin.

Animals↗

PubMed1996

Isolation and characterization of endothelial cells from different organs of fetal pigs.

The purpose of this study was to isolate endothelial cells from different organs of porcine fetuses and to examine the binding of endothelial markers including lectins. Endothelial cells were isolated from the aorta, cerebral cortex, myocardium, ovary and testis. Binding of the antibodies to von Willebrand factor (vWF) and angiotensin converting enzyme (ACE), the presence of Weibel Palade bodies (WPB), uptake of acetylated low density lipoprotein (acLDL), and labelling with the lectins Bandeiraea simplicifolia agglutinin I (BS I), Peanut agglutinin (PNA), Dolichos biflorus agglutinin (DBA) and Ulex europaeus agglutinin I (UEA I) were examined. Cell preparations displayed cobblestone-like morphology with the exception of testicular endothelium, which formed arcuate structures. Endothelium isolated from the brain labelled more strongly than any other cell line with the lectin PNA, but it did not express ACE. In contrast to other cell preparations, myocardial endothelium showed very low binding of anti-vWF. Ovarian endothelium was able to perform in vitro angiogenesis. Moreover, these endothelial cells possessed the largest number of WPB. Testicular endothelium displayed highest binding of vWF. Endothelium isolated from the aorta, in contrast to all other endothelial cells, did not take up acLDL. These results demonstrate that organ- and tissue-specific heterogeneity is already expressed in fetal endothelium.

Animals↗

PubMed1996

Localization of the mRNA encoding the zona protein ZP3 alpha in the porcine ovary, oocyte and embryo by non-radioactive in situ hybridization.

The mRNA of the zona pellucida glycoprotein ZP3 alpha was localized in frozen sections of pig ovaries, isolated oocytes and early embryos by in situ hybridization using biotinylated oligonucleotide probes. In follicles, the distribution of mRNA for ZP3 alpha was correlated with the developmental stage: in primordial and primary follicles, the mRNA was shown to be predominantly localized in the oocyte. In secondary follicles, mRNA was found in both the oocyte and follicle cells. In tertiary and preovulatory follicles, the follicle cells showed distinct staining, whereas the oocyte was labelled weakly. In the early embryo, i.e. 2 days after fertilization, mRNA for ZP3 alpha could not be demonstrated. Our results suggest that, in the pig, the zona pellucida protein ZP3 alpha is synthesized by the oocyte and the follicle cells in sequence. After fertilization, synthesis of ZP3 alpha is terminated.

Animals↗

PubMed1996

Differences of microvascular endothelium in the bovine corpus luteum of pregnancy and the corpus luteum of the estrous cycle.

The purpose of the present study was to investigate potential modulations of endothelial cells of the bovine corpus luteum (CL) during pregnancy. Luteal endothelia of pregnant and non-pregnant cows were isolated and purity of cultures was verified by flow cytometric quantification of three independent endothelial markers (von Willebrand factor, angiotensin converting enzyme, Bandeiraea simplicifolia agglutinin I ligands). Different cellular parameters including light and electron microscopical investigation of morphology and growth characteristics as well as quantification of cellular lectin binding sites were compared. Extensive heterogeneity between luteal endothelial cells in pregnant and non-pregnant animals could be demonstrated, reflected in functional attributes like angiogenic activity, ultrastructural characteristics and the quantitative expression of cellular carbohydrates. Two different morphological types of cells ("cob-blestone growth pattern' and "arcuate growth pattern') were isolated from the CL of pregnancy as well as from the cyclic CL. Spontaneous angiogenic activities, including cellular migration in band-like structures and formation of ring-like structures, were observed in endothelial cells isolated from the CL of pregnant cows exclusively. This strongly suggests that microvascular luteal endothelium of pregnant animals, in contrast to the one of non-pregnant animals, is able to produce quantitatively and/or qualitatively specific angiogenesis factor(s). Heterogeneity between luteal endothelial cells in the pregnant and non-pregnant animal could also be demonstrated by quantification of lectin (Bandeiraea simplicifolia agglutinin I, concanavalin A, Dolichos biflorus agglutinin, Ulex europaeus agglutinin I, wheat germ agglutinin) binding sites: quantitative expression of specific endothelial cell surface carbohydrates could be correlated to the status of pregnancy, thus emphasizing the actual need of quantification of lectin binding.

Animals↗

PubMed1995

Effects of hormones on the prostate in adult and aging men and animals.

Literature on the effect of steroid hormones (androgens, estrogens, and other steroids), of peptide hormones (e.g., prolactin), and growth factors (e.g., EGF, FGF, TGF-beta), on the effect of castration and of experimental hormone application on the prostate is reviewed. Androgens have inductive, repressive, and interactive effects. They counterbalance an agonistic effect on proliferation and an antagonistic effect on cell death; they may influence DNA synthesis and induce the synthesis of substances with mitogenic effects on the prostate. Estrogens exert direct and indirect effects on the prostate. They suppress the secretion of gonatropins, thus repressing testicular androgen secretion. They stimulate the fibromuscular stroma and induce squamous metaplasia of the epithelium. Estrogens may also be involved in the onset of benign prostatic hyperplasia. Prolactin is preferentially bound in the diseased human prostate. An abundance of information has been gained on EGF, FGF, TGF-beta, and other growth factors. They may be involved in the development of prostatic hyperplasia. Castration leads to a striking reduction in prostatic size in a short period of time due to autophagic and heterophagic processes. In castrated individuals, the prostate is enriched in androgen-independent cells. Experimental hormone application involves the substitution of androgens as well as anti-androgens, long-term application of different hormones, and application of combinations of drugs. The results of several studies are described. Further directions in the field of prostate research should concentrate on the role of growth factors in prostate development and pathology and on the effect of certain lectins on prostate diseases. We think that the investigation of interactions between steroid hormones and growth factors in normal and pathological neovascularization of the prostate is important.

Adult↗

PubMed1995

Quantitative differences in neoglycoprotein binding for vascular endothelial cells from porcine brain, ovary, and testis in vitro.

Carrier-immobilized carbohydrates are valuable tools for assessing the glycoligand-binding capacity of cell surfaces. A panel of 10 types of fluorescent neoglycoproteins has been synthesized to determine the extent of their specific binding to endothelial cells in vitro that have been obtained from porcine brain, ovary, and testis. Different sugar moieties revealed a nonuniform capacity to bind to the endothelial cells as determined by flow cytometric analysis, the histogenetic origin of the preparations being an important factor. Binding of mannose, xylose, and glucuronic acid was especially pronounced, but the extent of cell-associated fluorescence was significantly different dependent on the source of the endothelial cells. These results clearly reveal that endothelial cells in vitro display the capacity to specifically recognize defined carbohydrate moieties. Moreover, endothelial cells of different tissue origin can exhibit variability in this property, potentially endowing this cell type with site-dependent molecular properties.

Animals↗

PubMed1995

Early expression of chromogranin A and tyrosine hydroxylase during prenatal development of the bovine adrenal gland.

The present study was undertaken to define the temporal pattern and distribution of cells positive for chromogranin A (CgA) and tyrosine hydroxylase (TH) in various developmental stages of fetal bovine adrenal gland. CgA is an acidic protein, co-stored and co-released with amines and a variety of peptide hormones and neurotransmitters in dense core vesicles of neural and endocrine cells and can be used as a marker for these cells and their malignant counterparts. TH is the rate-limiting enzyme in catecholamine biosynthesis and reflects noradrenergic differentiation. The expression of CgA and TH was examined by immunohistochemistry. CgA immunoreactivity appears first in 35-day-old bovine fetuses. By the end of the second month, CgA-labelled cells are scattered throughout the entire primordium of the adrenal gland, and at a fetal age of 85-91 days most of these cells concentrate in the developing adrenal medulla. From this stage onwards, immunoreactive cells of the marginal zone of the medulla exhibit significantly stronger CgA immunoreaction than the central area. TH immunoreactivity appeared in the adrenal primordium for the first time at the end of the second month of gestation. The distribution pattern of TH-positive cells was similar to that described for CgA, and no significant differences in topographical arrangement between TH- and CgA-positive cells can be detected. The results show that bovine adrenal chromaffin cells express CgA already during their earliest stages of development and prior to TH. The stronger immunoreaction of marginal adrenal medullary cells suggests an adrenalcortical effect of glucocorticoids on the expression of CgA.

Adrenal Glands↗

PubMed1995

A transformed murine myocardial vascular endothelial cell clone: characterization of cells in vitro and of tumours derived from clone in situ.

In the course of maintaining a cloned murine myocardium-derived endothelial cell line (mouse heart endothelial cell clone 5; MHEC5) a spontaneously transformed variant has been identified (clone MHEC5-T). On injection into histocompatible mice, clone MHEC5-T uniformly generated epithelioid haemangioendotheliomas. Clone MHEC5-T underwent significant additional alterations in addition to the acquisition of tumour-forming potential in vivo along with the diagnostic correlate of loss of cellular contact inhibition in vitro. Whereas the transformed cells maintained lectin-binding properties characteristic of endothelial cells, they lost the cell surface receptor(s) for acetylated low density lipoprotein and no longer bound antibodies to either angiotensin converting enzyme or von Willebrand factor-associated antigen. Vascular cell adhesion molecule-1 (VCAM-1), expressed constitutively on the parent clone, was down-regulated in the transformed cell line. The transformed cells acquired immunoreactivity to antibodies directed against cytokeratin, and they showed a markedly increased response to migration-inducing factors in vitro. The cell line described in this report demonstrates that the in vitro transformation of myocardium-derived endothelial cells can lead through transitional stages of differentiation to a new stable phenotype characterized by endothelial--to--epithelioid transition. The study of MHEC5-T cells, in addition to providing insight into the biology of cardiac neoplasms, may help to elucidate regulatory mechanisms involved in endothelial cell activation, transition and transformation.

Animals↗