摘要:

AbstractWe used biochemical and structural approaches to analyze the influence of gonadotropic hormones on the association of hepatic lipase with specific subsets of ovarian blood vessels. Western blotting was used to detect this enzyme in effluent collected from heparin‐perfused ovaries of nonhormone‐treated immature rats and those primed with pregnant mare's serum gonadotropin (PMSG) alone or in combination with human chorionic gonadotropin (hCG). The effects of these hormones on hepatic lipase distribution among oyarian blood vessels was assessed before and after hCG and/or PMSG treatment by immunofluorescence and immunogold cytochemistry. For the latter, immunoreagents and fixative were delivered directly to chilled, unfixed ovaries by in situ vascular perfusion. Data from biochemical and structural analyses indicated that hepatic lipase was absent from nonhormone‐treated ovaries. As shown by Western blotting of ovarian effluent, the enzyme appeared following treatment with PMSG and PMSG‐hCG; it increased in amount in a time‐dependent manner, with a transient decline in the early hours after hCG injection. Enzyme levels paralleled growth and vascularization of follicles and corpora lutea; the fall tended to coincide with early events in luteal angiogenesis. Immunogold microscopy showed that hepatic lipase was abundant in thin‐walled blood vessels of theca interna of follicles, corpora lutea, and interstitial cells but sparse in those of the stroma. Moreover, during neovascularization of differentiating corpora lutea, vascular sprouts arising from hepatic lipase‐laden thecal vessels appeared to lose, then regain, the enzyme as development progressed. Our findings thus suggest (1) that hormones influence the establishment of endothelial cell heterogeneity within the microvasculature of a single organ and (2) that development of novel endothelial cell properties in specific subsets of blood vessels underlies compartmentalization of function within a tissue. © 1993 W

ISSN:0003-276X    

DOI:10.1002/ar.1092350402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractDystrophin is a high molecular weight protein localized under the sarcolemma of normal extrafusal muscle fibers but absent in skeletal muscle of Duchenne muscular dystrophy patients and mdx mice. Muscle spindles in the soleus of 32‐week‐old normal and age‐matched mdx mice were examined by immunocytochemical methods to determine the localization of dystrophin in polar and equatorial regions of the intrafusal fibers. Spindles were serially sectioned in transverse and longitudinal planes, and were double‐labelled with an antibody to dystrophin and with an antibody to a 200 kD neurofilament protein, which revealed their sensory innervation. By fluorescence microscopy, intrafusal fibers in the soleus of mdx mice were deficient in dystrophin throughout their lengths, whereas their sensory nerve terminals stained intensely with the nerve‐specific antibody and appeared unaltered in dystrophy. In the normal soleus, intrafusal fibers displayed a regional variability in the distribution of dystrophin. Polar regions of bag and chain fibers exhibited a peripheral rim of sarcolemmal staining equivalent to that seen in the neighboring extrafusal fibers. Dystrophin labelling in equatorial regions of normal intrafusal fibers, however, showed dystrophin‐deficient segments alternating in a spiral fashion with positive‐staining domains along the sarcolemma. Double‐labelling for dystrophin and neurofilament protein showed that these dystrophin‐deficient sites were subjacent to the annulospiral sensory nerve wrappings terminating on the intrafusal fibers. These findings suggest that dystrophin is not an integral part of the subsynaptic sensory membrane in equatorial regions of normal intrafusal fibers and thus is not directly related to sensory signal transduction. The complete absence of this protein in mdx intrafusal fibers indicates that these fibers exhibit the same primary defect in muscular dystrophy as seen in the extrafusal fibers. However, because of their small diameters, capsular investment, and relatively low tension outputs, dystrophic intrafusal fibers may be less prone to the sarcolemmal membrane disruption that is characteristic of extrafusal fibers in this disorder. © 19

ISSN:0003-276X    

DOI:10.1002/ar.1092350403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractThe ultrastructure of renal tubule cells was studied in the European lesser spotted dogfish by the evaluation of thin sections and freeze fracture replicas. Computer‐assisted three‐dimensional reconstruction of entire nephrons was performed. The distinction of nephron segments and collecting tubule was made using results of previous histological work. The first proximal tubule segment (PI) consists of two subsequent portions, PIa and PIb. PIa is a component of the lateral countercurrent bundle, and PIb, which displays an apical tubulovesicular apparatus and an extended lysosomal compartment, is located in the vicinity of the glomeruli. Rod‐shaped intramembrane particles were detected in PIa. The second proximal tubule segment (PII) is a special segment in elasmobranch and teleost fish. PII differs largely from PI in cell morphology and function. The apical cytoplasm was filled with small clear vesicles, and an apical endocytic apparatus was lacking. In the apical cell membrane, rod‐shaped particles were revealed by freeze fracture. The apical tight junctions of PI and PII consisted of seven to ten meandering strands. The distal nephron was subdivided into two major segments: early distal tubule (EDT) in the lateral countercurrent bundles and late distal tubule (LDT) in the mesial tissue. The EDT showed marked amplification of basolateral cell membranes. The tight junctions displayed a low number of continuous parallel strands, which is also characteristically found in the diluting segments of other vertebrates. LDT cells showed cytoplasmic studs and rod‐shaped intramembraneous particles at the apical cell membrane, thereby resembling type A intercalated cells of collecting duct. The collecting tubule (CT) emerged from the LDT and was part of the countercurrent arrangement inside the lateral bundles. Tight junctions of LDT and CT consisted of many meandering strands in a honeycomb pattern. With immunohistochemistry, binding sites of a polyclonal antibody against an extraplasmic portion of rat gastric H+‐K+‐adenosine triphosphatase (ATPase) were observed at the apical cell membrane of PIa, PII, and LDT. From the colocalization of binding sites for the antibody against the transport enzyme with rod‐shaped intramembrane particles, we assume that these might be the morphological correlate of gastric H+‐K+‐ATPase‐like enzyme in the renal tubule.

ISSN:0003-276X    

DOI:10.1002/ar.1092350404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractFormation of the blood‐urine permeability barrier in differentiating mouse transitional urothelium was studied. It was established that the development of superficial cell barrier is a two‐phase process: beginning with formation of the tight junctions, followed by formation of fusiform vesicles and asymmetric apical plasma membranes. Fusiform vesicles differentiate during days 15 and 17 of gestation and fuse with the apical plasmalemma. Thus a thick membrane is formed before the excretion of hypertonic urine into the embryonic bladder. Through some degenerative superficial cells slough between fetal day 17 and the day of birth, the bladder epithelium in mice does not lack an effective permeability barrier. © 1993 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092350405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractA morphometric analysis of mouse sperm and of their nuclei was undertaken to investigate their respective post‐testicular maturation. Sperm were collected from the testis, caput and cauda epididymidis, and their corresponding nuclei were isolated. Results indicate that the post‐testicular maturation of sperm is distinct from that of nuclei. The size of intact sperm heads increases in the caput followed by a subsequent decrease in the cauda. In contrast, sperm nuclei decrease progressively in size. In general, a greater magnitude and number of alterations in intact heads and nuclei occur while in transit from the testis to the caput than during passage to the cauda epididymis. These results suggest that the period immediately following their release from the testis is crucial to the complete morphological maturation of sperm heads and nuclei. © 1993 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092350406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractRapid and complete withdrawal of intratesticular testosterone was achieved via the destruction of all Leydig cells with the specific Leydig cell cytotoxin ethane dimethanesulphonate (EDS). Restoration of testosterone levels was accomplished by administration of a single dose (25 mg) of testosterone esters (T) known to reverse the antispermatogenic effects of androgen withdrawal. Quantitation of the degenerating germ cells in cross sections of seminiferous tubules (ST) at stages IV–V, VII, IX, and X–XI of the spermatogenic cycle was used as a sensitive biological index of the effects of testosterone withdrawal and restoration upon the function of the Sertoli cells. Compared to control testicular tissues, the mean numbers of pyknotic germ cells per ST cross section at stages VII, IX and X–XI increased significantly (P<0.01–0.001) between 4 to 8 days post‐EDS treatment, but only in stage VII tubules was this trend reversed significantly (P<0.005) within 2 days by T supplementation. In EDS‐treated rats, stages VII, VIII, IX, and X‐XI also exhibited significant (P<0.05–0.001) increases (compared to controls) in the volumetric proportions by which intraepithelial vacuoles appeared within the seminiferous tubules. Again, in EDS+T supplemented rats, the appearance of vacuoles was significantly (P<0.001) suppressed in stage VII and VIII. In contrast to tubules at stages VII‐XI, those at stages IV–V were completely unaffected by testosterone withdrawal or replacement. The results show that at selected time intervals after EDS treatment, testosterone supplementation is capable of preventing/reversing these morphological changes within 2 days in stage VII tubules. It is suggested that the induction and subsequent prevention of seminiferous epithelial damage will serve as an important in vivo and in vitro approach for studies on the androgen‐mediated changes in Sertoli cell biology during phases of impairment and recovery of their function. Manipulation of adult Sertoli cell function as provided by our model should permit identification of androgen‐regulated gene products together with an understanding of their role(s) in normal and abnormal spermatogenesis.

ISSN:0003-276X    

DOI:10.1002/ar.1092350407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractOur objective was to characterize epithelial cells, lamina propria, and sites of estrogen coupling in the caput, corpus, and cauda regions of the human epididymis using antibodies to cytokeratin types; epithelial membrane antigen; laminin; type IV collagen; vimentin; desmin‐, and estradiol‐receptor‐related protein; and immuno‐histochemical techniques. Principal cells immunostain by both AE1/AE3 antibodies (keratins 1–8, 10, 13–15, and 19) and anti‐pan‐keratin antibodies (keratin 5, 6, and 8). Immunoreactions to both anti‐keratin antibodies increase from the caput to the cauda epididymis. The principal cells only immunostained by antikeratin 19 antibodies in the cauda and showed no reaction to keratins 10 and 11. Basal cells and apical cells immunoreact to anti‐AE1/AE3, antipan‐keratin, and antikeratin 19 antibodies, but not to antikeratin 10 and 11 antibodies, in all three epididymal regions. The principal cells immunoreact with epithelial membrane antigen antibodies in the stereocilia and subjacent cytoplasm. This immunostaining decreased from the caput to the cauda. Antivimentin antibodies stained the apical cytoplasm of principal cells and limited areas of both principal cells and basal cells. This immunoreaction decreased from the caput to cauda. Apical cells immunostained in the three regions. Immunoreaction to ER‐D5 was moderate in the principal cells, basal cells, apical cells, and muscular coat cells in the cauda. The apical cells immunostained in the three regions. Antilaminin antibodies stained the epithelial basement membrane in the three regions. Type IV collagen was detected in the basement membrane as well as around the muscular coat cells in the three regions. Immunoreaction to desmin was intense in the muscular coat cells in the three regions. Thickness of the immunostained area for both type IV collagen and desmin increases from the caput to the cauda. The differences in immunostain pattern along the epididymis length seem to be related to regional differences in function.

ISSN:0003-276X    

DOI:10.1002/ar.1092350408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractWe have developed a co‐culture system suited for the study of epithelial‐mesenchymal interactions in the human fetal small intestine. As the epithelial component of this model, we used the human intestinal cell line Caco‐2 that is unique in its property to differentiate in vitro into a mature fetal enterocyte‐like cell type. A sheet of human intestinal mesenchymal cells, which we derived from an 18‐week‐old fetus, was used as mesenchymal element. Expression and distribution of cell‐specific markers (cytokeratin 18 and dipeptidyl peptidase IV), major basement membrane components, and β1 integrins were analyzed. In 14‐day co‐cultures, Caco‐2 cells formed a cytokeratin 18‐positive epithelial‐like sheet covering the vimentin‐positive HIM cell layers. As assessed by brush border dipeptidyl peptidase IV expression, co‐cultured Caco‐2 cells achieved cytodifferentiation as when cultured on plastic. A complete deposition of all known major human fetal intestinal basement membrane components occurred at the Caco‐2/HIM interface. Type IV collagen and tenascin were produced from the mesenchymal compartment, whereas laminin and fibronectin were contributed by both cell types. Interestingly, synthesis and deposition of basement membrane heparan sulfate proteoglycan were exclusively observed in co‐cultures, suggesting modulation of epithelial expression of this molecule by HIM cells. Finally, we observed that epithelial integrin‐β1 chains redistributed at the basal domain of co‐cultured Caco‐2 cells. Taken to gether, these observations indicate that the Caco‐2/HIM co‐culture model is a valuable system to study in vitro human basement membrane formation in the context of intestinal epithelial‐m

ISSN:0003-276X    

DOI:10.1002/ar.1092350409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractCell‐to‐cell communication by gap junctions was investigated in the male rat anterior pituitary gland following several experimental regimens involving castration. The regimens included the following animals: (1) Group 1, castrated at 10‐day intervals from day 10 to 50 and sacrificed at 60 days of age; (2) Group 2, castrated every 10 days from days 10 to 50 and sacrificed 50 days after castration; (3) Group 3, castrated at 5 days of age and sacrificed every 10 days from day 10 to 60; or (4) Group 4, remained intact and sacrificed every 10 days from days 10 to 60. In all of the castrated animals, numerous so‐called castration cells were scattered throughout the pars distalis of the pituitary gland, with occasional “signet ring cells” being observed. In Groups 1 and 2, the pattern of gap junction development and their number was no different from the intact control (Group 4). In contrast, the number of gap junctions in the animals castrated on day 5 remained very small even into adulthood. These data demonstrate that gonadal steroids are important in the intial development of gap junctions within the pituitary gland but are not necessary to sustain their presence once an animal becomes an adult. © 1993 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092350410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY

摘要:

AbstractA newly described type of cutaneous gland occurring in the human anogenital region was investigated in specimens from the vulva by electron microscopy. This gland, which is characterized by a long excretory duct opening at the skin surface, by a wide coiled secretory part with multiple lateral extensions in the form of diverticula and branches lined by a two‐layered pseudostratified of myoepithelium, and by a luminal layer of tall columnar cells with conspicuous “snouts”, could not be categorized as an eccrine, apocrine, or mammary gland. Electron microscopy confirmed its separate position by showing that the luminal layer of secretory cells with prominent cytoplasmic caps had elaborately folded lateral membranes, occasional canaliculi, and a large number of uniform electron‐lucent to moderately electron‐dense secretory granules as part of a probable merocrine secretion. The excetory duct showed a poorly developed cuticular border. This combination of ultra‐structural features is alien to the other tubular cutaneous glands. The function of this anogenital “sweat” gland remains obscure, but the presence of these granules suggests a secretion product that is different from that of other cutaneous glands. © 1993

ISSN:0003-276X    

DOI:10.1002/ar.1092350411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1993

数据来源: WILEY