ISSN:0003-276X    

DOI:10.1002/ar.1092140315

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

年代:1986

数据来源: WILEY

摘要:

AbstractA new approach to quantification of Sertoli cells is described. The number of Sertoli cells per testis was calculated from the number of spermatids per testis, the number of spermatids per Sertoli cell apex, and the correction for the lifespan of spermatids enumerated per testis. To evaluate this method under different physiological conditions, testes from 28 adult (4–20‐year) stallions obtained in the nonbreeding season (December–January) and from 28 adult stallions in the breeding season (June–July) were compared. Number of Sertoli cells per gram parenchyma was similar between seasons. However, the number of Sertoli cells per testis was significantly greater in the breeding season. In verification of this method, the number of spermatids per Sertoli cell apex was similar to that calculated as the ratio of spermatids to Sertoli cell in the same stallions. Likewise, absolute values similar to those of other approaches further verify the validity of this a

ISSN:0003-276X    

DOI:10.1002/ar.1092140302

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

年代:1986

数据来源: WILEY

摘要:

AbstractPurified boar sperm plasma membranes (PM) and PM proteins were used as antigens to produce 58 monoclonal antibodies against surface antigens. Fluorescence labelling (biotin‐avidin‐FITC) was used to determine the distribution of antigens in caput and cauda epididymal and in ejaculated spermatozoa with hybridoma supernatants and/or 1:100 diluted ascites fluid after subcloning. Sixteen areas (subdomains) of apparent restricted antigen mobility were identified and significant differences in the localization of most antigens in caput, cauda, and ejaculated PM were recognized. While localization patterns were highly reproducible with a given protocol for sample preparation and immunolabelling, localization patterns were markedly affected by changes in protocols. Fluorescence patterns were affected by the manner in which sperm were labelled (live sperm or sperm labelled at various steps), by washing, and by temperature or by addition of seminal plasma. These results indicate that the dynamic properties of the sperm PM or the surrounding fluids can easily mask or unmask or reconfigure binding sites for highly site‐specific monoclonal antibodies and that antigen distribution is probably underestimated when these labelling techniques are used. Such changes in the accessibility of antigenic sites to monoclonal antibodies limited determining the extent of distribution of a given antigen on epididymal sperm. However, the reproducibility of patterns when a given protocol is used and the large number of antibodies (39/42) displaying marked differences in localization on caput, cauda, and ejaculated PM suggest that changes in the organization of the PM constituents, whether by addition or subtraction of antigen or through configurational changes in proteins, are a major consequence of sperm maturation in the epidi

ISSN:0003-276X    

DOI:10.1002/ar.1092140303

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe organization and fine structure of granular convoluted tubule cells (GCT) from male mouse submandibular glands have been examined in controls and in animals injected with adrenergic and cholinergic secretagogues. Control submandibular glands exhibited a single population of GCT cells with numerous homogeneous granules filling the apical two‐thirds of the cytoplasm. A zone of transition cells, exhibiting characteristics of both GCT and striated duct cells, was found between the agranular intercalated duct and GCT segments. These transition cells possessed apical granules of variable size as well as prominent basal striations.Dramatic changes in the morphology of GCT cells followed administration of the α‐adrenergic agent, phenylephrine. The extensive degranulation involved formation of “secretory pools” of fused granules and release of secretory material into the lumen. The appearance of numerous smooth vesicles near luminal membranes suggested extensive membrane retrieval. Intracellular membrane‐limited aggregates of membrane fragments suggested that much of the retrieved membrane was destined for degradation. Rough endoplasmic reticulum was highly dilated but there was no indication of increased size or activity of the Golgi complex.Ultrastructural evidence indicated that the secretory responses to isoproterenol, a β‐adrenergic agent, and to pilocarpine, a cholinergic agent, were much more modest, but it is clear that some secretory response to these agents does occur. The other cell types of the duct and tubule system did not exhibit comparable morphological changes in response to th

ISSN:0003-276X    

DOI:10.1002/ar.1092140304

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

年代:1986

数据来源: WILEY

摘要:

AbstractIn an endeavor to delineate an alveolar configuration that would reasonably mirror the natural state, polygonal shapes of normal alveoli were tabulated in histologic sections from inflation‐fixed specimens of 16 men aged 16–48 years. The resulting alveolar population varied from three‐ to ten‐sided polygons with a preponderance of tetragons, pentagons, and hexagons. These observations were compared with the possible combinations of polygonal sections through various polyhedral models proposed by other workers and the five classical regular polyhedrons. The potential types of sections through the regular dodecahedron, i.e., a twelve‐sided shape with faces consisting of pentagons, seemed to fit best with present findings, and this is suggested as an idealized configuration that might be useful in various geometric determinations, e.g., estimates of alveolar surface area a

ISSN:0003-276X    

DOI:10.1002/ar.1092140305

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe objective of this study was to provide a detailed account of the morphogenesis and early cytodifferentiation of the hamster cheek pouch. Although the newborn “cheek pouch” is used for in vitro studies of the effects of retinoids and carcinogens, its rudimentary structure has not been adequately described. Complete paraffin serial sections of the heads of 14‐ and 15‐day fetuses were cut in three planes to determine the location and shape of the earliest pouch rudiments. Complete paraffin serial sections were prepared from pouch rudiments dissected from hamsters at birth and at daily intervals from 3 to 12 days postnatal. Semithin Epon sections were examined by light microscopy and ultrathin sections by transmission electron microscopy. The pouch can appear in the fetus as two solid epithelial ingrowths from the lining of the oral cavity. They are the margins of an ingrowing sheet of oral epithelium which becomes leaflike at about the time of birth, as it grows caudad into the tissue of the cheek. The central cells of the ingrowth accumulate large quantities of glycogen before differentiating as a stratum spinosum 5 days after birth. Within the stratum spinosum, groups of cells containing keratohyalin granules initiate the stratum granulosum. Keratinized cells appear within the stratum granulosum areas. Spaces appear between keratinized cells, and the spaces coalesce to form the pouch cavity between 7 and 12 days postnatal. Soon afterward, this cavity opens to the oral cavity to make a pouch, and the ultrastructure of the cheek pouch epithelium closely resembles that of th

ISSN:0003-276X    

DOI:10.1002/ar.1092140306

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

年代:1986

数据来源: WILEY

摘要:

AbstractNexuses (gap junctions), the morphological correlates of direct cell‐to‐cell communication, were consistently detected between granulosa cells of primordial follicles in the ovaries of adult cycling, juvenile, or neonatal mice. To examine the ontogeny of these intercellular channels, the cellular interactions occurring during the fetal stages of folliculogenesis, which culminate in the formation of primordial follicles, were analyzed in ovaries from fetal days 13, 15, 17, and 19. On fetal day 13, the ovary is characterized by clusters of germinal cells and invading rete ovarii cells. The rete cells progressively penetrate the ovary and wall off clusters of oocytes by fetal day 17, at which time rete cells can be recognized as presumptive granulosa cells. Gap junctional contacts can be recognized between rete cells on day 13 and these contacts persist as the cells become recognizable as presumptive granulosa cells throughout ovarian histogenesis. Quantification of junctional contacts from days 15–19 indicated that the number of gap junctions increases with fetal age. In addition heterocellular gap junctional contacts were detected between oocytes and presumptive granulosa cells as early as fetal day 17, indicating that the potential for direct intercellular communication between granulosa cells and oocytes is established from the earliest co

ISSN:0003-276X    

DOI:10.1002/ar.1092140307

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

年代:1986

数据来源: WILEY

摘要:

AbstractLeft forelimbs of postmetamorphicXenopus laevisfroglets were repeatedly denervated prior to and following amputation. Amputations were performed 14, 21, 28, or 42 days after the original denervation. A tissue‐regenerative response resulting in the formation of a spike‐shaped, heteromorphic outgrowth was found in the sham‐denervated and control animals, but dedifferentiation of the stump tissues was not apparent. Tissue‐regenerative outgrowths were not observed in the denervated cases; instead, dermal wound healing and stump and scar formation occurred. In both control and experimental cases, however, a periosteal proliferative response to amputation injury led to the development of a greatly thickened periosteum the length of the amputated radius‐ulna as well as a cap of cartilage at the distal end of these bones. We conclude from these results that forelimbs of postmetamorphic froglets are incapable of adjusting to a prolonged nerveless state sufficient to allow the normal tissue‐regenerative response of spike outgrowt

ISSN:0003-276X    

DOI:10.1002/ar.1092140308

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

年代:1986

数据来源: WILEY

摘要:

AbstractIntestinal development was noted from 27 days gestation. By 50 days gestation the ovine small intestine shows the beginnings of villus formation. The lumen becomes patent by 70 days. Proximal regions mature earlier than distal regions. Vacuolation of enterocytes occurs in all regions of the small intestine at some stage during development. Mature‐looking enterocytes can be found in proximal regions by 125 days gestation while in distal regions immature vacuolated cells can still be found just prior to birth. Enterocytes lining the villi are more mature at the villus tip than those at the base in all regions. This gradient of maturation is consistent with a suggestion of the early establishment of adult patterns of proliferation and migration of enterocytes in the sheep fetu

ISSN:0003-276X    

DOI:10.1002/ar.1092140309

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

年代:1986

数据来源: WILEY

摘要:

AbstractThe anatomy of the teeth and tooth‐related nerves in the lower jaw was examined in the cichlidTilapia mariae. This was done in order to establish a basis for studies on dental neuroplasticity in a polyphyodont vertebrate. The region of interest was explored in specimens fixed by glutaraldehyde perfusion, and by using X‐ray photography, maceration, scanning electron microscopy, gross dissection, and light microscopic examination of serial sections. The results show that the lower jaw carries some 60–65 functional teeth. In addition, numerous replacement teeth and tooth germs in various stages of development are located in a cavity in the dentary bone. Numerous nerve bundles are present in immediate relation to the dental follicles of tooth germs. Unerupted teeth do not contain light‐microscopically discernible pulpal axons, but the pulps of functional teeth contain myelinated axons. Both perifollicular and pulpal nerve bundles derive from a nerve plexus, which is formed by branches from r. mandibularis trigemini. This nerve is easily accessible to experimental manipulation, where it courses through the adductor mandibulae muscular complex. Thus, the lower jaw ofT. mariaeseems to represent a suitable system for the study of tooth‐nerve interactions in a polyphyodon

ISSN:0003-276X    

DOI:10.1002/ar.1092140310

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

年代:1986

数据来源: WILEY