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F Sinowatz

Publications and source records attributed to F Sinowatz.

At least 127 records · Page 7Linked to original sources
PubMed1984

Con A- and WGA-binding sites on bovine epididymal spermatozoa: TEM of specimens in toto.

Binding sites for Con A and WGA were detected on bovine spermatozoa during epididymal maturation. We used colloidal gold as an EM-marker. The spermatozoa were treated according to a two-step method for lectin and colloidal gold, then adsorbed to lysine-coated nickel grids and subsequently examined by TEM in toto. Using this method we rapidly got information about the topographic distribution of lectin-binding sites. Major differences exist for WGA between caput and cauda spermatozoa. Conceding that cell-thickness poses some limitation, we consider this method to be practical and especially useful in studies concerning topographic distribution of cell surface components in single cell systems.

Animals↗
PubMed1984

Glycoproteins of bovine epididymal spermatozoa--a cytochemical study.

Modifications in bull sperm plasmamembrane during epididymal passage were investigated by the use of four different lectins: Concanavalin A (Con A); Ricinus communis I (RCA1); Wheat germ agglutinin (WGA); Ulex europaeus agglutinin I (UEA1). During sperm passage from caput to cauda epididymidis agglutination by RCA1 and WGA distinctly increased. Similar but somewhat less pronounced difference in the agglutinability was found for Con A. No agglutination was observed with UEA1. Ultrastructural examination of Con A binding sites on sperm plasma membrane with a Con A-horseradish peroxidase-gold technique (Con A-HRP-G) revealed a significant increase in the number of gold granules on the sperm tails during the epididymal passage of spermatozoa. No change in WGA-binding sites was observed between caput and cauda spermatozoa using a WGA-peroxidase method.

Agglutination↗
PubMed1984

[Enzyme histochemical studies of the swine placenta. Histoptics of enzymes in interareolar placental epithelia].

In porcine interareolar placental epithelia, the following enzymes were demonstrated by histochemical methods after 30, 58, 80, 100, and 110 d of pregnancy, respectively: beta-N-acetylhexosaminidase, beta-galactosidase, beta-glucuronidase, alpha-mannosidase, acid phosphatase, alkaline phosphatase, nonspecific esterases, cytochrome oxidase, 5-nucleotidase, leucine aminopeptidase, adenosine triphosphatase, diaphorases (NADH, NADPH), glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase (NAD, NADP), beta-hydroxybutyrate dehydrogenase, glycero-3-phosphate dehydrogenase, NAD-glycero-3-phosphate dehydrogenase, glutamate dehydrogenase (NAD, NADP), lactate dehydrogenase. The results show that most of the enzyme activities remained almost unchanged during the period of investigation. Only G-6-PDH and 6-PGDH activities increased within the uterine epithelium and nonspecific esterase activity within uterine as well as chorionic epithelia during the 2nd half of pregnancy. Within chorionic and uterine epithelia, hydrolases but not dehydrogenases demonstrated a higher activity at the bases of chorionic villi as compared to the apices and flanks of the latter. The action and influence of the demonstrated enzymes on metabolism, energy transfer, secretory, and resorptive activities of chorionic and uterine epithelia are discussed.

Animals↗
PubMed1984

[Early changes in the dog prostate after castration. An ultrastructural study].

Using electron microscopic techniques the prostate glands of male Beagle dogs were studied 3 days after castration. At this time marked differences in the extent of alterations of the glandular epithelium were observed: Whereas several acini showed only minor changes with reduction of epithelial height and diminution of secretory granules, many acini were severely affected with pronounced alteration of cellular structure and accumulation of large lipid droplets. A constant feature was the stimulation of the basal cells of the grandular epithelium. Additionally, in some areas of the gland aggregations of stimulated basal cells forming an acinus-like structure with a slit-like lumen were found. Our study shows that castration leads to marked alterations of prostatic epithelium within a short time. Androgen deprivation causes regressive changes of secretory epithelial cells, but clearly stimulates the basal cell population.

Animals↗
PubMed1983

Uterine glands of the pig during pregnancy. An ultrastructural and cytochemical study.

The ultrastructure of the porcine uterine glands is described from material taken from 11 pregnant pigs at exactly known stages of gestation (day 30; 58; 80; 100; 110). Fixation was performed by perfusion via a branch of the uterine artery and the tissue was routinely processed for electron microscopy. Additionally, cytochemical studies (phosphotungstic acid reaction for glycoproteins, according to Rambourg 1967; acid phosphatase reaction; ultrastructural localization of cellular iron, according to Parmley et al. 1978) were performed. On day 30 of pregnancy the uterine glands are coiled, simple tubular glands with a narrow lumen. The epithelial lining is simple columnar and consists basically of two cell types, ciliated cells and secretory cells. The secretory activity of the glandular epithelium is low; only a few secretory granules are present in the supranuclear cytoplasm. At midpregnancy the ultrastructure of the glands has significantly changed and the cells now show all the characteristics of high secretory activity: numerous parallel cisternae of rough endoplasmic reticulum, an extensively developed Golgi apparatus and many secretory granules which give a positive reaction for acid phosphatase and glycoproteins. The lumina of the glands are significantly enlarged and filled with a great amount of a granular, acid phosphatase-positive material. In the last third of pregnancy, only minor changes in the ultrastructure of the uterine glands are observed. The secretory activity is still high. The amount of rough endoplasmic reticulum has further increased and parallel arrays of cisternae occupy a considerable part of the supranuclear cytoplasm. The importance of the uterine secretion for embryonic nutrition and development is only partly understood. One of the secreted glycoproteins, uteroferrin, is believed to play an important role in the iron transfer from mother to fetus. From midpregnancy onward, a special cell type, the "granule laden cell" is found scattered between normal secretory cells of the uterine glands. Contrary to the opinion of Perry and Cromby (1982), we could demonstrate that these cells frequently extend to the lumen of the gland; hence the term "basal cell" seems inappropriate for this cell type.

Acid Phosphatase↗
PubMed1983

Localization of lectin receptors on bovine epididymal spermatozoa using a colloidal gold technique.

Mammalian spermatozoa that leave the testis are neither motile nor fertile. Maturation of spermatozoa occurs during epididymal transport. Among the changes during epididymal passage alterations of the surface properties of spermatozoa appear especially interesting. In this report we describe ultrastructural localization of Con A and WGA-binding sites on bovine spermatozoa from caput and cauda epididymides using a indirect lectin-horse-radish-peroxidase gold technique. With Con A the plasma-membrane covering the sperm head was heavily labelled with gold granules in caput as well as in cauda epididymal spermatozoa. A different distribution was observed for WGA-binding sites. The acrosomal region of caput and cauda spermatozoa was heavily labelled with gold, both in caput and cauda spermatozoa. The postacrosomal region was only sparsely marked in caput sperm whereas in sperm cells originating from the cauda a calix like membrane area displayed intense labelling. Some differences in the number of binding sites were also seen on sperm tails: those of caput spermatozoa show generally more Con A binding sites that those from cauda epididymal spermatozoa. No changes in the number of WGA-binding sites on sperm tails was observed during epididymal passage. The technical aspects of the indirect lectin-horse-radish-peroxidase gold technique are briefly discussed.

Animals↗
PubMed1983

Histochemical localization and quantification of glucose-6-phosphate dehydrogenase in bovine leydig cells.

Some of the critical steps in the qualitative histochemical localization of glucose-6-phosphate dehydrogenase (freezing procedures, incubation techniques and the influence of intermediate electron carriers, respiratory chain inhibitors and different tetrazolium salts) were evaluated in sections of bovine testis as a prerequisite for the microdensitometric estimation of the activity of the enzyme in bovine Leydig cells in situ. A modification of the gel incubation method of Rieder et al. (1978) gave the best results and was used for the quantitative investigations. Quantitative data for the dehydrogenase activity gained from microdensitometry of the formazan final reaction products in Leydig cells in situ were compared with the results of assays of the activity in homogenates of testis. The following apparent kinetic properties of glucose-6-phosphate dehydrogenase were obtained for the enzyme in Leydig cells in situ: Vmax = 0.11 absorbance units/min, Km = 0.37 mM. The quantitative characterization of glucose-6-phosphate activity in Leydig cells in situ appears to be suitable for combined morphological and functional diagnoses of small tissue samples such as testicular biopsies. This would give valuable information of the functional status of Leydig cells in normal and diseased testicular tissue.

Animals↗
PubMed1983

Renal mesangial cell cultures as a model for study of erythropoietin production.

Mesangial cells derived from isolated glomeruli of rat kidney were grown as homogeneous cell lines in culture. They released, into the culture medium, erythropoietin that had free terminal galactosyl residues and was therefore not active in vivo. The production of erythropoietin by these cells was significantly enhanced by either lowering the PO2 in the incubation atmosphere or by adding cobalt chloride to the culture medium. Therefore, mesangial cells in culture may be considered as an in vitro system in which the regulation of erythropoietin production can be studied under well-defined conditions.

Animals↗
PubMed1982

Intraprostatic and subcutaneous transplantation of a spontaneous prostatic carcinoma (11095) to male Fischer rats (F344): an ultrastructural study.

A prostate carcinoma arising spontaneously in a Fischer rat was transplanted by cell suspension to male and female Fischer rats. Tumour growth was rapid in both subcutaneous and intraprostatic sites of inoculation in males and subcutaneously in females. The growth rate was greater in male than in female hosts and the tumour developed as a solid form in both groups. It had a heterogeneous cell population with ultrastructural characteristics similar to basal cells of the normal prostate and to tumour cells seen in human prostate adenocarcinoma. Later stages of tumour growth transformed it to a cornifying squamous cell carcinoma. The morphological description of tumours produced by transplantation provides the basis for further studies using this method as a model for investigating the response of prostate carcinoma to endocrine manipulation.

Adenocarcinoma↗
PubMed1982

The fine structure of the terminal segment of the bovine seminiferous tubule.

The intratesticular excurrent duct system of the bull is composed of rete testis, tubuli recti, and the terminal segment of the seminiferous tubules. Each terminal segment is surrounded by a vascular plexus and may be subdivided into a transitional region, middle portion, and terminal plug. The modified supporting cells of the middle portion and the terminal plug no longer display the typical Sertoli-Sertoli junctions seen in the transitional region and the seminiferous tubule proper. In the region of the terminal plug a distinct central lumen is generally not observed: spermatozoa and tubular fluid must pass through an intricate system of communicating clefts between the apices of the closely attached modified supporting cells. Vacuoles in the supranuclear region of the cells in the middle portion indicate strong transepithelial fluid transport. In analogy to the epithelium of rete testis and tubuli recti, the supporting cells of the terminal segment are capable of phagocytosing spermatozoa. The vascular plexus investing the terminal segment serves a dual purpose: it is a regulatory device for fluid and sperm transport, as well as an area of increased diapedesis for white blood cells.

Animals↗
PubMed1981

Development of the bovine acrosome. An ultrastructural and cytochemical study.

In the present study the development of the bovine acrosome was investigated using conventional electron-microscopical techniques as well as the phosphotungstic-acid (PTA) technique (Rambourg 1967) including enzymatic digestion experiments. As in other species and in accordance with previous light-microscopical studies (Clermont and Leblond 1955) four phases of acrosomal differentiation can be discerned; the Golgi-phase, cap-phase, acrosome-phase, and maturation-phase. In the bull no internal pattern of the acrosomal content can be observed, either with conventional uranyl acetate-lead citrate staining or with the PTA-techniques. Our results support the observation in other species (Fawcett et al. 1971) that no intrinsic polymerization or crystallization process of the acrosomal content is responsible for acrosomal shaping. Some of our results suggest the influence of external forces on acrosomal development in the bull. During the cap-phase and the acrosome-phase accumulation of smooth endoplasmic reticulum and a layer of fine filaments can be observed in the Sertoli-cell cytoplasm, immediately adjacent to the developing acrosome. A temporary influence of these structures on acrosomal development seems possible. The PTA-positive staining of the developing bovine acrosome is probably due to the presence of acrosomal glycoproteins; however, our results do not exclude the possibility that molecules other than glycoproteins contribute to the positive PTA-staining of the developing acrosome.

Acrosome↗
PubMed1981

Intertubular topography in the bovine testis.

The intertubular stroma of the bovine testis is composed of narrow strands between two adjacent tubules and larger tri- and quadrangular interstices between three to four tubules. The latter contain the majority of Leydig cells, larger blood vessels and testicular lymph vessels. Leydig cells occur in groups or cords, not every cell being in close contact to a capillary, lymph vessel or venule. Between adjacent Leydig cells intercellular canaliculi and gap junctions are frequently encountered. Bovine Leydig cells are further characterized by an abundance of ribosome-associated endoplasmic reticulum, by mitochondria often containing crystalloid structures and displaying both tubular and lamelliform cristae, as well as by a relative paucity of lipid droplets and lysosomes. Independent of the size of intertubular lymph vessels their walls consist only of an endothelium of varying thickness, no typical basal lamina or associated musculature being present. The interstitial surface of the endothelium sends anchoring cytoplasmic pedicles into the subjacent ground substance and collagen fibrils. Among occasional plasma cells, mast cells and mononuclear leucocytes, a regular constituent of the intertubular region studied is a population of electron-lucid, irregularly shaped cells (light intercalated cells = LIC) with slender, pleomorphic processes. These cells are believed to be involved in testicular androgen storage and distribution.

Animals↗
PubMed1981

The ultrastructure of dog epididymis.

The ultrastructure of the epididymal duct and ductuli efferentes in the dog has been studied by electron microscopy. The epididymidis can be separated into the classical divisions of caput, corpus and cauda epididymidis on the basis of general morphology and ultrastructure. The ductuli efferentes have a low epithelium with pronounced cilia at the apices of cells and appear to provide primarily a transport role for spermatozoa. In the epididymis proper the caput region is characterized by an extremely large Golgi apparatus with large numbers of lysosomes and nuclear inclusions. Secretory activity appears to be most common in the corpus region. Absorption and secretion are most active in the first two segments while in the cauda epididymidis the long-term storage of spermatozoa in the lumen is associated with many dense crystalline bodies formed in the epithelial cells within the Golgi apparatus and possibly deriving from absorbed macromolecular material from the lumen. The theory of whole sperm cell resorption by the epididymal duct is not supported by this study.

Animals↗
PubMed1981

The placenta of the pig. II. The ultrastructure of the areolae.

The ultrastructure of the areolae in the porcine placenta is described. The areolae occur on day 30 of pregnancy as dome-shaped formation over the openings of the uterine glands. The lumen of the areolae is filled with the secretions of the uterine glands, the so-called histiotroph. The areolae lining epithelium is high collumnar, possessing long microvilli, a well-developed apical tubular system and numerous coated vesicles. This indicates that the epithelium has a high absorptive capacity. Our histochemical investigations reveal a high content of glycoproteins within the areolar lumen. The importance of one of the glycoprotein components of the histiotroph, uteroferrin, is discussed in connection with iron transfer from mother to the fetus.

Animals↗
PubMed1980

The placenta of the pig. I. Finestructural changes of the placental barrier during pregnancy.

The finestructural changes of the interareolar porcine placenta during pregnancy are described. After perfusion fixation of the placenta the change in the thickness of the placental barrier from day 30 to day 110 of gestation is much more evident than after immerson fixation as has been used by all former authors. The alterations are due to the indentation of both the trophoblast and uterine epithelium by their corresponding capillary-network. This indentation is limited to the lateral wall and the summit of the chorionic ridges, while at the base the trophoblast as well as the uterine epithelium remains high columnar. This indicates that in the interareolar porcine placenta, which is represented by the chorionic ridges and the corresponding endometrial folds, at least two different areas with different structure and function may be discerned. 1) The lateral side and the top of the chorionic ridges seem to be predestinated for gaseous exchange. The placental barrier in this area is often less than 2 micrometers. 2) The transport of blood-borne nutrients takes place at the base of the chorionic ridges. This transport seems to be facilitated by an intercellular channel system between the uterine epithelial cells.

Animals↗