摘要:

AbstractThe distribution of four basement membrane components: laminin (LAM), type IV collagen (Coll. IV), heparan‐sulfate proteoglycan (HSPG), and entactin (ENT), was studied by immunocytochemistry in primary cultures of adult rat anterior pituitaries. In such cultures, the pituitary cells are deprived of their normal environment of adjacent cells and basement membranes (BM), and of the connectivo‐vascular system of the hypophysis. In this dissociated system, pituitary cells grow as small clusters upon a monolayer of fibroblasts.LAM was found highly expressed in endocrine and in folliculo‐stellate cells. Very small amounts of Coll. IV, but neither HSPG nor ENT, could be detected in endocrine cells. In contrast, in fibroblasts, very large amounts of Coll. IV, HSPG, and ENT, and a lower quantity of LAM were detected. At the ultrastructural level, the immunoreactive components present within the cells were located in the subcellular compartments involved in the elaboration of exported products. In addition to that intracellular distribution, the four constituents were observed in an extracellular matrix which appeared between the cultured cells, either as an amorphous material, or as a more or less dense reticular network, weakly stained with anti‐LAM, but strongly stained with the other antibodies.Thus, the present immunocytochemical data support the implication of pituitary endocrine cells, at least for LAM secretion, in the elaboration of a novel extracellular matrix in primary cultures. In addition, a cooperation with non‐endocrine cells seemed to be required for the production of the four BM components. © 1992 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092330102

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

年代:1992

数据来源: WILEY

摘要:

AbstractWe have investigated the presence of cells containing monoamines, substance P, and neuron‐specific enolase (NSE) in the heart and in the pericardial wall of a urodele amphibian, the axolotl. Fibers containing substance P‐like immunoreactivity were present in the heart but not in the pericardial wall. Also present in the heart were small branched cells, which stained metachromatically with toluidine blue. Similar cells were found in the peritoneum and were tentatively identified as mast cells. NSE‐immunoreactive fibers were found both in the heart and in the pericardial wall. Small intensely fluorescent (SIF) cells of the pericardial wall contained a high concentration of norepinephrine but no other monoamines, substance P, or NSE. Comparison with data available for the mudpuppy,Necturus maculosus, a closely related amphibian species, suggests that the innervation of the heart in the axolotl is substantially different. © 1992 Wiley‐L

ISSN:0003-276X    

DOI:10.1002/ar.1092330103

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe aim of this study is to describe the presence of neuroendocrine (NE) cells (paraneurons), producing biogenic amines and/or peptidergic hormones, in the female urethra of cattle, sheep, pigs, and horses, by means of histochemical and double labeling immunofluorescent techniques. 5‐Hydroxytryptamine‐, chromogranin A‐, cholecystokinin‐ and somatostatin‐containing NE cells are present in the urethral epithelium of all the species studied, with the unique exception of the lack of somatostatin cells in the horse. Paraneurons containing 5‐hydroxytryptamine colocalized with chromogranin A or cholecytokinin were also found in all subjects. Such active substances are hypothesized to play a role in the contraction of the urethral musculature, emission of urogenital fluids, and inhibition of endocrine and exocrine secretions. © 1992 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092330104

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

年代:1992

数据来源: WILEY

摘要:

AbstractArchitecture of semimembranosus lateralis muscle (SMI), an almost parallel‐fibered muscle with bony origin and aponeurotic insertion of its muscle fibers, was studied in male Wistar rats of two age groups. Using photographic techniques and maximal stimulation active muscle architecture was determined at muscle optimum length. Muscle length increases were almost similar with fiber length increases (approximately 36%). Aponeurosis length increased (by 31%) as did angle of the aponeurosis with the line of pull (approximately 4°). Angles of the proximal as well as distal fibers with the line of pull were unchanged. Increases in mean fiber diameter were estimated to be approximately 50%. It is likely that increased mean fiber diameter was accommodated at the bony origin by enlargement of its area. At the aponeurosis increased mean fiber diameter was accommodated by increased length of the aponeurosis as well as a change in fiber angle with the aponeurosis. This change in fiber angle proved to be different in the proximal and distal part of the aponeurosis. Under the assumption of a uniform change in fiber diameters, a gradient of length change along the aponeurosis occurs. It is concluded that growth in an almost parallel‐fibered muscle with a bony attachment results in different architectural adaptations in the parts close to the bony attachment as compared to those close to the aponeurosis. This difference is due to the fact that adaptation of aponeurosis angle with the line of pull occurred, which was not the case for angle of the line of origin with the line of pull. © 1992 Wiley‐Li

ISSN:0003-276X    

DOI:10.1002/ar.1092330105

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe cytodifferentiation of peritubular myoid cells was studied in developing rats from fetal day 18 through approachment of puberty. The parameters taken into consideration were (1) the presence of desmin, a component of intermediate filaments in contractile cells; (2) the expression of alkaline phosphatase, a cell surface enzyme present in no other cell type of the seminiferous tubule; (3) the expression of the smooth muscle specific isoform of alpha‐actin, a marker of terminal differentiation in smooth muscle cells; (4) cell proliferation rate, evaluated in radioautography as labeling index after incorporation of3H‐thymidine in short‐term organ culture; and (5) cytoarchitectural changes detected with scanning electron microscopy. By means of immunofluorescence and cytochemistry it was observed that the three markers are expressed early during life, long before the onset of the first spermatogenic wave; in particular desmin is already present in fetal samples and alkaline phosphatase activity appears a few days after birth, whereas α‐smooth muscle isoactin is first detected around birth. As for myoid cell replication, the high prenatal labeling index was found to drop soon after birth and to further slow down during the first month of postnatal life, suggesting that myoid cell proliferation is not a major factor in peritubular expansion. SEM examination of developing peritubulum has shown that, when approaching puberty, the myoid cell undergoes a dramatic change in cytoarchitecture, consisting in extreme flattening and cytoplasmic expansion resulting in an apparent increase in peritubular surface. © 1992 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092330106

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

年代:1992

数据来源: WILEY

摘要:

AbstractWe studied the immunohistochemical and ultrastrural distribution of laminin in ovaries of immature and mature rats. When sections from 1–8‐week‐old rat ovaries were labeled directly with conjugates of affinity purified anti‐laminin IgG‐horseradish peroxidase (HRP), the antibodies bound to all ovarian basement membranes including those surrounding follicles in different stages of maturation. In addition, intracellular labeling was seen in granulosa and theca cells of follicles undergoing rapid development (preantral and antral stages) and in basement membrane‐like structures of the Call‐Exner bodies. Intracellular laminin was generally not detected, however, in any cells of primordial or atretic follicles. Tissue processed for immunoelectron microscopy 1 hour after the intravenous injection of anti‐laminin IgG‐HRP showed binding of antibody in linear patterns along endothelial and follicular epithelial basement membranes. Discontinuous strands of laminin‐positive, extracellular matrices were also seen between theca cells of all follicles. In addition, injected anti‐laminin IgG labeled perisinusoidal basement membranes located within corpora luteae and patches of basement membranes material between granulosa lutein cells. When ovaries were examined 5 d after the intravenous injections of anti‐laminin IgG‐HRP, uneven or segmented labeling was found in subepithelial basement membranes surrounding developing follicles. Our results therefore indicate that granulosa and theca cells participate directly in basement membrane laminin biosynthesis and suggest that this new laminin is spliced into existing basement membranes during follicular growt

ISSN:0003-276X    

DOI:10.1002/ar.1092330107

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe morphology of the extratesticular rete and ductuli efferentes was reexamined in serial cross sections collected from the entire mass of the efferent ductules and in longitudinal sections collected from the partially unraveled efferent ductules. The extratesticular rete forms a 3–4‐mm‐long sac‐like dilatation, which, within the head of the epididymis, has a wide lumen (up to 4 mm) and gives off along its length numerous evaginations, which, in turn, make connections with the ductuli efferentes. The latter is a mass of 16–18 ductules lined by three types of nonciliated cells: type II cells are characterized by dense, periodic acid‐Schiff (PAS)‐positive granules; type III cells are characterized by empty‐appearing, PAS‐negative vacuoles; and type I cells lack both granules and vacuoles. The distribution of the three types of nonciliated cells varies along the length. Whereas only type I cells are present in the beginning portion of the efferent ductule, type II cells predominate in the middle portion and type III cells in the distal portion (near the epididymis). The transition from one cell type to the other type is gradual; thus there are short segments along the length that share characteristics first for type I and type II cells and then for type II and type III cells. These results demonstrate that different nonciliated cell types are not randomly distributed in the epithelium of the ductuli efferentes but, instead, gradually differentiate from type I to type II to type III cells along the length of each efferent ductule. Factors controlling this differentiation remain to be studied. © 19

ISSN:0003-276X    

DOI:10.1002/ar.1092330108

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

年代:1992

数据来源: WILEY

摘要:

AbstractActin, α‐actinin, and tropomyosin were localized in the testicular, epididymal, and ejaculated spermatozoa and in the epithelium of the bovine epididymis by means of specific antibodies using an indirect immunofluorescence technique. Immunocytochemical results were confirmed by the western blot analysis. Independent of the method of fixation, washing, or sonication, actin, α‐actinin, and tropomyosin were all consistently localized in the neck of the spermatozoa. Actin and tropomyosin present in the postacrosomal area could be removed by sonication, whereas α‐actinin in the basal plate appeared to be resistant to the treatment. In the unwashed spermatozoa α‐actinin‐specific immunofluorescence was seen over the acrosomal area, whereas in the washed sperm it appeared as a narrow cap at the margin of the head. In the latter location, its distribution was similar to that of tropomyosin. In the majority of preparations, tropomyosin could be localized in the principal piece of the tail. Even though some actin‐specific immunofluorescence could be identified in the principal piece of the tail of the testicular and epididymal spermatozoa, a strong immunoreaction appeared only in the ejaculated spermatozoa. In the principal cells of the epididymal epithelium, specific fluorescence for actin, α‐actinin, and tropomyosin occurred in the apical junctional complex. Basal bodies of the solitary cilia of the epididymal epithelium were labelled with antitropomyosin and anti‐α‐actinin antibodies. Besides offering new information about the cytoskeletal composition of the mammalian sperm, the present results support the hypothesized homology between the connecting piece of the sperm neck and the basal body of the cilia.

ISSN:0003-276X    

DOI:10.1002/ar.1092330109

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe localization, morphology, and neurohormonal peptide content of neuroendocrine cells have been extensively investigated. Relatively little is known about the kinetics of growth and differentiation of these cells. We studied the kinetics of enterochromaffin (EC) cells in the caecum of the rat, by applying the thymidine analogue 5‐bromo‐2′‐deoxyuridine (BrdU), to identify cells in S‐phase, administered in pulse‐chase and synchronous continuous labeling experiments. By double indirect immunofluorescence staining of tissue sections, using antibodies against serotonin and BrdU, percentages of BrdU positive EC cells could be enumerated, from which cell‐kinetic parameters were derived. The following conclusions were drawn: (1) EC cells are renewed by proliferation of EC cells and by recruitment from proliferating precursor cells. (2) Caecal EC cells appear to consist of a relatively rapidly renewing and migrating fraction (60–65%) with a turnover time of approximately 16 days and a relatively slowly renewing and possibly stationary fraction (35–40%) with an estimated turnover time of approximately 150 days. (3) Seventy percent of the EC cells are localized in the lower half of mucosal crypts, 30% in the upper half. After prolonged labeling the percentage of labeled EC cells in the lower crypt half always exceeds that in the upper crypt half. This decrease in labeled EC cells during migration towards the mucosal surface indicates loss of endocrine cells, possibly owing to loss of endocrine characteristics. © 19

ISSN:0003-276X    

DOI:10.1002/ar.1092330110

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

年代:1992

数据来源: WILEY

摘要:

AbstractGonadotrophs in the anterior pituitary gland of the musk shrew were first identified by means of electron microscopic immunocytochemistry. The gonadotrophs of the musk shrew revealed quite unusual ultrastructural features that have never been seen before in other species.These cells contained two types of secretory granules, i.e., small dense, roundshape granules and large lucent, irregular‐shape granules. FSHβ and LHβ were mostly observed together on both small and large secretory granules. The distribution pattern of the subunits of gonadotrophs was slightly altered following gonadectomy in the musk shrew. © 1992 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092330111

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

年代:1992

数据来源: WILEY