摘要:

To contrast the previously described distribution of 5α-reductase isoenzyme 2 in human organs we have raised synthetic C-terminal peptides of human 5α-reductase isoenzyme 1 (h5αcr1) and isoenzyme 2 (h5αr2), respectively, and studied the cellular and subcellular distribution of both isoforms of this key enzyme of testosterone metabolism using the human prostate gland as a reference. h5arl, which in Western blots of human prostatic proteins had an apparent molecular weight of 23 kDa, was localized immunohistochemically in the nucleus of prostatic epithelial and stromal cells. Ultrastructurally, it was closely associated with the nuclear matrix. The apparent molecular weight of h5αcr2 was 26 kDa in Western blotting of human prostatic proteins. In immunohistochemically processed sections, it was seen in the cytoplasm of prostatic epithelial as well as stromal cells. An organ screening with genital and extragenital tissues of males and females was performed to elucidate the distribution of the isoenzymes. Presence of both isoenzymes was demonstrated for a number of tissues, including the central nervous system, the urogenital tract, the respiratory tract, the gastrointestinal tract, skin, and the endocrine system. The divergent localization of 5α-reductase isoenzymes points to potentially different functions in various organs. In view of the nuclear localization of isoenzyme 1, its close spatial relationship with the androgen receptor is presumed to indicate a close association with the receptor mech

ISSN:1422-6405    

DOI:10.1159/000147852

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

In the female bird sperm is stored in a quiescent mode, but full motility is needed for successful fertilisation. Regulation of sperm motility is thus of vital interest and the pH is a factor of importance. For this reason the localisation of carbonic anhydrase in the vagina, uterovaginal junction and infundibulum was studied with a histochemical method. Carbonic anhydrase catalyses the reaction C02 + H20 H+ + HCO-3 and is known to take significant part in acid-base regulation in the body. The enzyme was found in all regions with the highest activity, both cytoplasmic and membrane-bound, in the non-ciliated cells of the uterovaginal surface epithelium. Intense membrane-bound activity was also found in both the infundibular grooves and glands with slightly less in the sperm storage tubules and vaginal epithelium. Occasionally cytoplasmic and nuclear staining was seen. Changes in pH affect sperm motility and our results provide the first evidence for cellular mechanisms that makes rapid changes of the pH possible in these regions. Judging from the distribution of carbonic anhydrase we suggest two possible functions: (1) increasing pH and/or adding bicarbonate ions to stimulate sperm motility needed for the transfer to the storage sites and at fertilisation, and (2) a lowering of the pH in the sperm storage sites to keep the sperm quiescent during storag

ISSN:1422-6405    

DOI:10.1159/000147853

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The structure of a chelonian eggshell is of prime importance for the developing embryo. It acts as a protective covering as well as mediator in the exchange of heat and water. The fresh eggshell of the olive ridley (Lepidochelys olivacea) turtle displays a variety of structural forms in their aragonite framework. Its netted substrate, loose texture and poorly organised crystallites favour the easy exchange of air and water during its development. The shell consists mostly of calcium in carbonate form and K, Mg, Fe, Ni, Pb, Zn, Co, Cr, Cu, Mn and Cd in traces. Ba and Sr in traces are also a feature of the thermal analysis graph. Phosphorus was not detected in the shell and its absence eliminates an earlier suggestion of it being a key factor in the development of aragonite crystals in the inorganic structure of marine turtle eggshells. Its combustion characteristics, which have not been previously reported, are recorded.

ISSN:1422-6405    

DOI:10.1159/000147854

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The present study was designed to analyze the connective tissue compartment in the terminal region of the developing rat lung. Lungs of rat fetuses (at 17, 19 and 21 days of gestation) and of newborns (2, 4, 7, 10, 14 and 21 days after birth) were examined by several ultrastructural techniques: staining with tannic acid for elastic fibers (EFs), collagen fibers (CFs) and basement membranes (BMs); staining with ruthenium red for glycosaminoglycans; and immunoelectron microscopy for visualization of collagen type IV, laminin and fibronectin (FN). Dynamic changes in the levels and distribution of the components of the extracellular connective tissue were observed in parallel with the formation and maturation of the alveoli. The terminal regions of the respiratory tract of the rat fetus and of the lungs of early newborns contained few CFs and EFs, and the BMs in these lungs were incomplete. However, strong immunolabeling of FN was observed (in BMs, CFs and in spaces among fibroblasts). Starting from 4 or 7 days newborns had increasing numbers of CFs and EFs and BMs became more extensive. In rat newborns, immunolabeling specific for FN was weak and irregularly distributed. Furthermore, the present results provide a summary of the changes in connective tissue that occur in the rat lung during different stages of its development, from the pseudoglandular stage, through the canalicular and saccular stages, to the alveolar stage.

ISSN:1422-6405    

DOI:10.1159/000147855

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

The present paper demonstrates the immunohistochemical distribution of proteoglycan (PG) molecules carrying chondroitin sulfate (CS) chains with 6-sulfated hexosamine residues, or CS and/or dermatan sulfate (DS) chains with 4-sulfated residues in the developing bovine ruminal papillae (RP) using monoclonal antibodies (mAbs) 3B3, 2B6 and M0225. These PGs carrying chondroitin 6-sulfate that were detected by mAb 3B3, and the glucuronic acid 2-sulfate-N-acetyl-galactosamine 6-sulfate unit that was detected by the mAb M0225 were distributed in the mesenchyme and epithelial basement membrane in the rumen, and were thus correlated to the outgrowth of the RP. The PG carrying DS was detected by the mAb 2B6 and was distributed in the lower region of the mesenchyme and intermuscular connective tissue during the development of the RP. These findings suggest that PGs carrying CS chains with 6-sulfation are involved in the growth of the RP, and that PGs carrying DS are involved in organization in the mesenchyme.

ISSN:1422-6405    

DOI:10.1159/000147856

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

This paper introduces the comparison of altricial and precocial birds as a model system for the study of patterns of intestinal growth. It reports on comparative morphometric and cytokinetic studies of intestinal growth in altricial European starling (Sturnus vulgaris) and precocial Japanese quail (Coturnix coturnix japonica). Morphometric data of five gut segments of neonates and adults of both species are provided to evaluate the growth of the intestine. A double labelling technique combining 3H-thymidine autoradiography with 5-bromo-2’-deoxyuridine immunohistochemistry gives labelling index, length of S-phase, and tissue turnover time for hatchlings and adults of both species. The results of morphometry show a similar pattern of intestinal growth in both species, a strong dependency of intestinal growth on body size, and a clear topographic separation of areas of cell proliferation from the functional mucosal epithelium. The results of the cytokinetic experiments indicate a constant length of the S-phase independent of species, development, and age. The 3H-thymidine labelling index is significantly higher in neonate quail than in neonate starling. Between adult animals of both species, the labelling index does not differ significantly except for the duodenum which has a higher index in starling. The turnover time necessary to replace the mucosal epithelium is 3 days in hatchlings of both species and ranges between 10 and 17 days in adults. A diurnal pattern of cell proliferation, as previously reported in adult quail, is not present in neonate quail. Thus, differences in intestinal growth among altricial and precocial birds are primarily based on size differences of proliferation areas whilst cellular proliferation rates have only minor impact on intestinal growth. The short turnover time and the high rates of cell proliferation suggest that the intestine is a flexible organ that may be adjusted in size and function to the actual needs of the growing bir

ISSN:1422-6405    

DOI:10.1159/000147857

出版商:S. Karger AG    

年代:1996

数据来源: Karger

摘要:

Chloroquine diverts secretory peptides from the regulated to the constitutive secretory pathway. The exact site and mechanism of the effect are not known. We studied the effect of increasing doses of chloroquine on the morphology of cultured melanotrophs from the rat pituitary. 40 μM chloroquine for 2 h, which perturbs intracellular pH gradients in melanotrophs without affecting secretion, caused swelling of a subpopulation of immature secretory granules. 200 uM chloroquine for 2 h, which diverts secretory peptides from the regulated to the constitutive pathway in the AtT-20 cell line, caused pronounced swelling of immature secretory granules, vacuolization of the trans-Golgi region and the appearance of myeloid bodies and multivesicular bodies in the cytoplasm. Golgi stacks were retained and Golgi cisternae only slightly dilated at both chloroquine concentrations. Mature secretory granules were not affected. Cationized ferritin was internalized and transported to the trans-Golgi region in the presence of 40 μM chloroquine while 200 μM chloroquine arrested internalized ferritin in peripheral multivesicular bodies. The study shows a heterogeneous effect of lower doses of chloroquine on immature secretory granules, providing a tool for studies on the relationships between condensation, acidification and peptide processing during granule formation. Chloroquine of 200 μM caused morphological changes typical for chloroquine toxicity and arrest of endocytic traf

ISSN:1422-6405    

DOI:10.1159/000147858

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147859

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147860

出版商:S. Karger AG    

年代:1996

数据来源: Karger

ISSN:1422-6405    

DOI:10.1159/000147851

出版商:S. Karger AG    

年代:1996

数据来源: Karger