摘要:

AbstractLiver units were investigated in pig livers by means of histologic serial tracing, physical model building, and computer‐aided three‐dimensional imaging. Observations of the argyrophilic connective tissue skeleton were based mainly on the celloidin‐embedded serial sections treated with silver impregnation. The parenchymal mass that clothed the initial segments of hepatic venous radicles was demarcated by fibrous septa which formed isolable units with two basic patterns: the simple hepatic lobule (SHL) and the compound hepatic lobule (CHL). Both lobule types presented regular limiting structures circumscribing each unit. Three‐dimensional studies revealed that 25% of the lobules in a section belonged to the SHL type and 75% to the CHL type, the latter being predominant among the surface lobules. When considered in only two dimensions, however, the SHL‐like lobules constituted the majority. Polygonal analysis disclosed that the pentagonal lobule was the most typical, instead of the “hexagonal” or “classic” lobule. The CHLs represented a multiaxial unit containing a system of venous tributaries in accordance with intralobular septation, whereas the SHLs were found with one axial vessel having a dendritic tendency at the incipient end; some SHLs were drained eccentrically by separate vessels into a sublobular vein. It was observed that, in dividing CHLs, whereas particular sinosoids were transformed into portal twigs, other sinusoids were changed into central venous tributaries. Fibrous deposition occurred along the septal‐line sinusoids, bringing into view the septum‐initiating plane. Fibroconnective tissue was supplied from the portal area and central (sublobular) adventitia, where portal triad structures and adventitial arterioles, respectively, were included. The findings of the present study facilitate the understanding of several characters of the lobules that have been reported previously, or occasionally postulated, such as the portal‐central bridging tendency, the intralobular arterioles or ductules, the translobular artery or portal vein, the “portal‐portal” or “portal‐central” anastomoses, and the apposition of pericentral zone close to periportal zone. Based on differences in argyrophilia of sinusoidal reticulum, in proportion of lobule types, and in vasculature, the anatomic heterogeneity of liver unity was demonstrable in zonality, regionality, a

ISSN:0002-9106    

DOI:10.1002/aja.1001910202

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

年代:1991

数据来源: WILEY

摘要:

AbstractThis study describes the immunocytochemical distribution of five neuropeptides (calcitonin gene‐related peptide [CGRP], enkephalin, galanin, somatostatin, and substance P), three neuronal markers (neurofilament triplet proteins, neuron‐specific enolase [NSE], and protein gene product 9.5), and two synaptic‐vesicle‐associated proteins (synapsin I and synaptophysin) in the spinal cord and dorsal root ganglia of adult and newborn dogs. CGRP and substance P were the only peptides detectable at birth in the spinal cord; they were present within a small number of immunoreactive fibers concentrated in laminae I–II. CGRP immunoreactivity was also observed in motoneurons and in dorsal root ganglion cells. In adult animals, all peptides under study were localized to varicose fibers forming rich plexuses within laminae I–III and, to a lesser extent, lamina X and the intermediolateral cell columns. Some dorsal root ganglion neurons were CGRP‐ and/or substance P‐immunoreactive.The other antigens were present in the spinal cord and dorsal root ganglia of both adult and newborn animals, with the exception of NSE, which, at birth, was not detectable in spinal cord neurons. Moreover, synapsin I/synaptophysin immunoreactivity, at birth, was restricted to laminae I–II, while in adult dogs, immunostaining was observed in terminal‐like elements throughout the spinal neuropil.These results suggest that in the dog spinal cord and dorsal root ganglia, peptide‐containing pathways complete their development during postnatal life, together with the full expression of NSE and synapsin I/synaptophysin immunoreactivities. In adulthood, peptide distribution is similar to that described in other mammals, although a relative absence of immunoreactive cell bodies was observ

ISSN:0002-9106    

DOI:10.1002/aja.1001910203

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

年代:1991

数据来源: WILEY

摘要:

AbstractThe seromucous acinar cells of the adult rat submandibular gland secrete a characteristic mucin glycoprotein and a family of unusual glutamine/glutamic acid‐rich proteins (GRP). Monoclonal antibodies to the mucin and GRP localized in a very few Type III cells in glands of newborn and 1 day‐old rats, using light and electron microscopic immunocytochemistry. Both mucin and GRP reactivities were present in the polymorphic Type IIIP granules during the 1st postnatal week. By 9 days after birth, the granules contained both mucin and GRP and were mucous‐like in appearance. At earlier stages, however, cells containing only GRP or mucin could be found, indicating that the initiation of GRP and mucin biosynthesis may not be coordinately regulated. No reactivity was seen in the neonatal Type I cells or in duct cells at any age. Northern and Western blot analysis showed GRP mRNA and protein levels to be barely detectable at birth, with marked increases during the first 2 postnatal weeks. In contrast, Western blots of B1‐immunoreactive proteins (B1‐IP) showed levels highest in the 1st week and markedly decreased in the adult. Immunocytochemical colocalization, using gold particles of different sizes, showed that the B1‐IP, mucin, and GRP colocalized in the granules. These results strengthen the hypothesis that the adult acinar cells develop from the neonatal Type III cells. No evidence was obtained for the involvement of Type I cells in the pathway of acinar cell

ISSN:0002-9106    

DOI:10.1002/aja.1001910204

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

年代:1991

数据来源: WILEY

摘要:

AbstractIn an effort to define further the factors that can influence trophoblastic growth, development of the discoidal chorioallantoic placenta was examined histologically in laboratorybred black mastiff bats,Molossus ater.This placenta normally forms only at the cranial end of the right uterine horn. Its positioning was found to be related to the development of an unusual vascular tuft in the endometrium at this site following ovulation. When a decidual reaction occurred, the endothelial cells of the tuft vessels hypertrophied and their basal laminae became more prominent in sections stained for glycoproteins. Cytotrophoblast then proliferated preferentially around the tuft in the right horn and its vessels became surrounded by trophoblastic cuffs. A functional placenta was formed when trophoblastic tubules grew out from these cuffs, became interconnected, developed lumina, and began to carry maternal blood. Maternal endothelial cells generally persisted only in portions of the larger vascular tubules.These observations suggest that the endothelial cells of the tuft vessels may be secreting factors that influence early trophoblastic growth and are at least partially incorporated into the basal laminae of the endothelial cells. Evidence is reviewed which raises the possibility that endometrial endothelial cells might have a similar morphogenetic role in many other mammals with invasive trophoblast.Mitotic activity in the trophoblastic tubules ofM. aterceased when the tubules became patent and began to carry blood. Further growth was then accomplished by hypertrophy of the existing cytotrophoblast cells. Electron microscopic examination of near‐term placentas confirmed that the interhemal barrier was hemomonochorial and lacked a continous layer of syncytiotrophoblas

ISSN:0002-9106    

DOI:10.1002/aja.1001910205

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

年代:1991

数据来源: WILEY

摘要:

AbstractMorphometric studies have confirmed that the corpus leteum (CL) of the pregnant rat contains luteal cells with numerous microvilli which directly face an extensive network of sinusoidal capillaries. From this it has been suggested that extensive development of transport structures is necessary to support progesterone synthesis and secretion. The present study was carried out to determine whether these transport structures could be related quantitatively to different rates of total progestin (progesterone plus 20 α‐hydroxypregn‐4‐en‐3‐one) secretion reported to be 32, 10, and 23 μg/hr per ovary on day 16 and the morning (AM) and afternoon (PM) of day 22, respectively.Histological analysis was carried out on two CL, fixed by immersion, from each of five rats, at each stage of gestation. The important findings to emerge were that when the progestin secretion rate was greater, there was a significant increase in surface specializations on the lutelal cell and a thickening of the capillary walls. There was also a greater volume of interstitial space between luteal cells and capillaries. However, due to the development of microvilli and unevenness in the capillary wall, the physiological diffusion distance (harmonic distance) between luteal cell cytoplasm and blood was not increased. Collectively, these results show that changes in the rate of progestin secretion are accompanied by significant, although disproportionate, changes in transport structures and suggest that the latter are important in supporting lute

ISSN:0002-9106    

DOI:10.1002/aja.1001910206

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

年代:1991

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001910201

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

年代:1991

数据来源: WILEY