摘要:

AbstractBackground: During the acute phase response to inflammation, the Golgi apparatus of rat hepatocytes processes an increased quantity of glycoproteins, in the form of acute phase reactants.Methods: The compartmental organization of the hepatocyte Golgi of control and 24 hour inflamed rats was studied, using transmission electron microscopic techniques, including cytochemistry, to detect nicotinamide adenine dinucleotide phosphatase (NADPase), thiamine pyrophosphatase (TPPase), and cytidine monophosphatase (CMPase) activity.Results: In inflamed rats, individual Golgi stacks were enlarged, but retained their organization into four compartments:1) a phosphatase negative, perforatedcis‐element, 2) two mid‐saccules which sometimes were positive for NADPase, 3) one or occasionally two NADPase and TPPase positivetrans‐saccules, and 4) a tubulovesiculartrans‐Golgi network (TGN) which was NADPase reactive and contained a spotty TPPase reaction product. Two of these compartments were noticably altered in response to inflammation. The two mid‐saccules were consistently and uniformly dilated. The TGN was altered to the point of being difficult to recognize and had acquired CMPase reactivity. In control rats the TGN consisted of anastomosing tubules forming cage‐like structures; secretory granules containing lipoprotein particles pinched off from these. In inflamed rats, most of the cage‐like TGN structures had been replaced with an extensive vesicular syncytium which produced secretory granules with a granulofilamentous content.Conclusions: In hepatocytes from inflamed rats an apparent switch had occured in the type of secretory material processed by the Golgi apparatus. Furthermore, the inflammation‐induced increase in the size of individual Golgi stacks apparently was not due to a parallel increase in size of all Golgi saccules. Rather, saccules within given Golgi compartments responded in a characteristic and specific manner to the increase in glycoprotein processing that occurs during inflammation. © 1995

ISSN:0003-276X    

DOI:10.1002/ar.1092410402

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The presence of extrarenal or local renin‐angiotensin system (RAS) has been noted in several tissues, although its functions have not yet been clarified. Renin from the coagulating gland (CG) is the most recently discovered local RAS and is a significant subject for investigation because large amounts of both mRNA and proteins are detected in this organ. Recently, it has been reported that testosterone influences renin synthesis in several extrarenal tissues, although it has no effect on intrarenal renin. Therefore, it is possible that CG renin is also regulated by testosterone.Methods: Forty‐four male C57BL/6 mice, aged 3 wk to 6 mo, were used in studies on the ontogeny and androgen regulation of the RAS in the CG. The tissues were fixed with Bouin's solution and paraffin sections were stained with immunohistochemical methods using antirenin antiserum. In each immunostained section, the relative number of renin‐containing cells in terminal portions of the CG were counted.Results: Immunoreactivity for renin was first detected at 6 wk after birth. After that time, the number of renin‐containing cells gradually increased throughout the experiment. In adults, several patterns of renin immunoreactivity were demonstrated in almost all epithelial cells of CGs, specifically; (1) basolateral granular reaction, (2) diffuse immunoreactivity throughout the cytoplasm, and (3) restricted nuclear reaction. Excretory products of some terminal lumina were also found to be positive for renin. At 10 days after castration, renin‐containing cells in ductal termini were decreased and remained at low levels until at 4 wk after castration. After testosterone injection, numerical values of renin‐containing cells were high at 1 wk and then decreased at 2–3 wk.Conclusion: It is suggested that CG renin of the mouse is expressed together with sexual maturation during development and that it depends on the testis, possibly the male sex hormone. © 1995 W

ISSN:0003-276X    

DOI:10.1002/ar.1092410403

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: DNA‐DNA hybridization studies suggest that Psittaciformes are highly, but not the most, derived nonpasserines. Multilocus protein electrophoresis indicates that cockatoos (Cacatuinae) form a monophyletic lineage distant from the other Australo‐Papuan psittacids (Psittacinae).Methods: Transmission electron microscope procedures are applied to the spermatozoa of three parrots, in the Cacatuninae and Psittacinae, to investigate these relationships.Results: Psittaciform sperm have the following characteristics: (1) conical acrosome vesicle; rodlike perforatorium; cylindrical, highly condensed nucleus; proximal and distal centriole embedded in dense material; elongate periaxonemal mitochondrial midpiece, (2) nine dense peripheral axonemal fibers (coarse fibers), (3) no fibrous sheath around the axoneme, (4) mitochondria with linear cristae, lacking intra‐ (or inter‐) mitochondrial dense bodies, (5) restriction of the endonuclear perforatorial canal to the anterior region of the nucleus, (6) a short distal centriole, and (7) nucleus abutting on but not penetrating the acrosome.Conclusions: (1) These features are tetrapod symplesiomorphies, (2) is an amniote synapomorphy; the fibers differ from those of reptiles in being uniform in size, (3) loss of the fibrous sheath is an apomorphy known elsewhere only in columbiforms, (4) are apomorphies relative to basal aminiotes (Chelonia,Sphenodon, and Crocodilia), (5) is an apomorphic condition shared with other nonpasserines (galliforms and the white‐naped crane) and crocodilians, (6) the latter taxa differ from parrots in a plesiomorphic elongation of the distal centriole, and (7) is a unique apomorphy of parrot sperm relative to other nonpasserines and reptiles. The short midpiece ofN. hollandicusdistinguishes this cacatuine from the two psittacines. © 1995 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092410404

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The objective was to develop an experimental model for studying the differentiation of trophoblast and inner cell mass (ICM) during the early stages of implantation in primates.Methods: Marmoset monkey blastocysts were used in these studies. Ovulation was timed by plasma progesterone assays in ovarian cycles initiated by administering a luteolytic agent to mating marmosets. Embryos were recovered from the uterus usually àt the eight‐cell stage and cultured in minimum essential medium containing fetal calf serum, insulin, and transferrin. The embryos that formed hatched hatched blastocysts by about day 11 after ovulation were transferred for further development in Matrigel‐coated culture chambers. After 2, 4, and 6 days of development, two blastocysts were processed at each interval and serially sectioned for light and electron microscopy.Results: All blastocysts adhered to the Matrigel at their embryonic pole within 24 hours. Adherent polar cytotrophoblast was differentiating to syncytiotrophoblast at all time intervals, but syncytium was not detected in mural trophoblast until day 4 after attachment. By day 2 syncytial microvilli and processes had penetrated the Matrigel surface, whereas by days 4 and 6 cytotrophoblast that was differentiating to syncytiotrophoblast had invaded the matrix. Since all blastocysts maintained their structural integrity progressive differentiation of the ICM, endoderm and presumptive mesoderm was observed. A small amniotic cavity was observed at 2 days and by 6 days a distinct cavity separated polarized epiblast and amnion cells. Visceral and parietal endoderm were present at 2 days, and a completed primary yolk sac was observed by 4 days after attachment. In all blastocysts a basal lamina lined the inner surface of mural and polar trophoblast and the basal surface of the differentiating ICM.Conclusions: The developmental time sequence of the cultured blastocysts closely resembled the time frame reported for marmoset embryos implanting in utero. An effective model for studying trophoblast invasion and differentiation of embryonic germ cell layers has been established. © 1995 Wiley‐Li

ISSN:0003-276X    

DOI:10.1002/ar.1092410405

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The gut‐associated lymphoid tissue of the rabbit cecum includes a single lymphoid patch located close to the ileocecal orifice. Vimentin immunoreactivity, which can now be regarded as a marker for M cells in rabbits, has identified a subpopulation of epithelial cells as M cells in the domes of this patch. The aim of the present study was to demonstrate that these M cells are capable of antigen transport and to characterize their ultrastructure.Methods: M cells of the rabbit cecal lymphoid patch were studied by scanning, thin section, and freeze‐fracture electron microscopy. The transcytosis across these M cells was investigated using horseradish peroxidase as a soluble tracer protein.Results: The M cells were concentrated at the flanks of the domes and had long, thick, branched microvilli, a well‐developed terminal web, and a deep invagination of their apical membrane. Numerous small vesicles lay beneath the terminal web in close vicinity to the base of the invagination. These vesicles transported the luminally applied horseradish peroxidase through the M cells. In contrast to adjacent enterocytes, the glycocalyx of M cells was thin, stub‐like, and had very few glycocalyceal bodies. Bacteria adhered to the surface of M cells and were also found in the apical invagination.Conclusions: The M cells of the rabbit cecal lymphoid patch differ from those of Peyer's patches of the small intestine in their ultrastructure and route of antigen transport. These differences might be related to the situations resulting from differences in the microbial populations at these locations. © 1995 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092410406

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: Knowledge of the structural arrangement of the cardiac conal valves in Elasmobranchs is scarce. The present study was designed to assess the anatomical and histological features of the conal valves of the dogfish as a starting point for further investigation of the mechanical properties of these valves.Methods: The sample examined consisted of 31 adult dogfishes. The study was carried out using scanning electron microscopy and histological techniques for light microscopy.Results: In the dogfish, the conus arteriosus contains two transverse rows of valves. The anterior row lies at the level of the conus‐ventral aorta junction and is composed of three valves of similar size. The posterior row is near the conus‐ventricular junction and consists of four valves, one of them very reduced in size. Each valve shows two components, namely, the leaflet and its supporting structure, the sinus. In the anterior valves, the length of the leaflets between their lateral attachments to the sinus wall is remarkably longer than the straight‐line distance between the points of attachment. This allows each leaflet to close against the other two leaflets of the same row, even when the conus is relaxed. The leaflets of the posterior valves are anchored to the conus wall by means of tendinous cords and cannot practically bridge the lumen of the relaxed conus. Each leaflet has a stout central body in which the connective tissue is stratified in three layers: outer fibrosa, spongiosa, and inner fibrosa. The lateral parts of the leaflet mainly consist of a single fibrous layer that bifurcates into the outer and inner fibrosa layers of the central body. The sinus walls of the posterior valves are entirely made up of conal tissue, whereas those of the anterior valves incorporate an aortic component.Conclusions: The present findings suggest that the inner fibrosa and the fibrous lateral portions of the leaflets mainly bear the stress of pressure generated by blood backflow. The stretching of the leaflets in the radial direction may basically depend on the spongiosa, whereas the outer fibrosa determines the radial stiffness of the leaflets. © 1995 Wiley‐L

ISSN:0003-276X    

DOI:10.1002/ar.1092410407

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: Hypophysectomy (HX) results in a cessation of bone growth and a decrease in bone metabolism. The purpose of this study is to examine the effect of HX on the static and dynamic histomorphometry of cancellous bone in the secondary spongiosa of the proximal tibial metaphysis in rats.Methods: Female rats, at 2 or 3 months of age, were HX and sacrificed at 0, 5 days, 2 and 5 weeks after the surgery. Age‐matched intact rats served as controls. Cancellous bone histomorphometry was performed on doublefluorescent labeled, 30‐um‐thick sections of the proximal tibia. Tartrateresistant acid phosphatase histomorphometry was performed at 5 days on HX and control rats to evaluate the resorption in the metaphyseal bone.Results: Although the intact rats gained in body weight, tibial length, tibial weight, and density after 5 weeks, these changes did not occur following HX. As compared to the basal group, HX resulted in a decrease in the density and dry weight of the metaphysis. The histomorphometric data showed that the cancellous bone volume and trabecular number of the secondary spongiosa were decreased and the separation was increased in the HX rats. The dynamic results showed that HX significantly decreased longitudinal growth rate and tissue‐based bone formation and resorption. However, the bone surface‐based eroded surface, labeled surface, the mineral apposition rate, and the bone formation rate did not differ between the intact and the HX rats at either the 2 or 5 weeks study. Five days after HX, the bone surface and tissue‐based osteoclast surfaces were significantly lower in the HX than in the intact rats.Conclusions: Pituitary hormone deficiency results in cancellous bone loss. The bone loss is due primarily to the suppression of longitudinal growth‐dependent bone gain and the inhibition of tissue‐based bone turnover with a lower bone formation relative to bone resorption. The surfacebased bone turnover is not affected. © 1995

ISSN:0003-276X    

DOI:10.1002/ar.1092410408

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: Pituitary hormones play an important role in bone growth, modeling, and remodeling. The purpose of this study is to examine the effect of hypophysectomy (HX) on tibial cortical bone with histomorphometry.Methods: Forty‐Five female Sprague‐Dawiey rats, at 3 months of age, were hypophysectomized or served as intact controls. They were sacrificed at 0, 2, and 5 weeks after the surgery. Cortical bone histomorphometry was performed on double‐fluorescent‐labeled 30‐mcm‐thick sections of the tibial shaft.Results: The dry weight and density of tibial diaphysis and the cortical bone area of the tibial shaft in the HX rats were significantly lower (P<0.05) than that of the age‐matched intact rats, but did not differ between the HX and basal control rats. The dynamic data show that the bone formation parameters (labeled surface, mineral apposition rate, and bone formation rate) were profoundly decreased (P<0.01) on both the periosteal and endocortical surfaces in the HX rats as compared with the age‐matched intact rats at the 2 and 5 weeks. However, the decrease in the labeled surface was much less on the endocortical envelope than on the periosteal envelope in the HX rats. Although no significant change was detected in the medullar size between the HX and age‐matched intact rats, the eroded surface on the endocortical surface was greater (P<0.05) in the HX rats than in the intact rats at either time point.Conclusions: Hypophysectomy‐suppressed, radial growth‐dependent bone gain without a bone loss in the tibial shaft of the young rat. This is associated with decreased modeling‐dependent bone formation. A greater eroded surface on the endosteum did not affect the marrow size at 5 weeks after hypophysectomy.

ISSN:0003-276X    

DOI:10.1002/ar.1092410409

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: The exposure of human neutrophils to uniform concentrations of chemoattractants, such as N‐formyl peptides, induces morphological cell polarization. In this study we report the temporal sequence of changes in cell shape, F‐actin, and cell surface morphology during cellular polarization induced by N‐formylmethionyl‐leucyl‐phenyl‐alanine (fMLP) in human neutrophils in suspension.Methods: Neutrophil shape changes induced by 10−8M fMLP were observed with DIC microscopy. Size and Cellular granularity were analyzed by flow cytometry measuring their forward and side scattered light. To visualize F‐actin distribution, neutrophils were labeled with the fluorescence probe FITC‐phalloidin, and were examined with fluorescence and confocal laser scanning microscopy. Cell surface morphology was assessed with scanning electron microscopy (SEM).Results: The stimulation of round‐smooth neutrophils with nanomolar concentrations (10−8M) of fMLP in suspension induced a temporal sequence of morphological changes during cell polarization, characterized by 1) increase in size as determined by forward angle scattered light, 2) rapid redistribution of F‐actin from a diffuse cytoplasmic localization to the cell periphery, and 3) rapid reorganization of cell surface morphological features, with accumulation of plasma membrane in the front of polar cells. Four cell shapes were identified with SEM after stimulation of round‐smooth neutrophils: round‐ridged, round‐ruffled, nonpolar ruffled, and polar cells. These cell shapes were correlated with a cortical localization, focal aggregates, and multipolar distribution of F‐actin. In polar neutrophils, F‐actin became concentrated in the front of the cell.Conclusions: These findings show the relation between reorganization of the microfilamentous cytoskeleton and modifications in cell shape and surface features during cell polarization induced after fMLP activation in neutrophils. This approach offers a powerful tool for further analysis of receptor distribution in polarized, motile ne

ISSN:0003-276X    

DOI:10.1002/ar.1092410410

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

年代:1995

数据来源: WILEY

摘要:

AbstractBackground: In contrast to the considerable amount of research that has been done on the proliferative activity of the several types of parenchymal cells in the developing submandibular glands of rodents, systematic studies of cellular proliferation in the developing parotid gland have been confined to the acinar cells. The purpose of the present study was to attempt to fill this knowledge gap.Methods: Tritiated thymidine was parenterally administered to Sprague‐Dawley rats at ages representative of the pre‐ and postnatal development of the parotid gland, and glands were harvested for autoradiography 90 min after injection. Mitotic activity among all cell types was verified by electron microscopy.Results: At all ages, the % labeled cells was much greater among the acini than any other cell type, including well‐differentiated cells at 25 and 40 days. However, there were only small alterations in the proportions of cells comprised by the major cell types.Conclusions: Current theories on the histogenesis of salivary glands and their neoplasms are based on the renewing population model, in which both normal differentiated cells and neoplastic cells arise from undifferentiated stem cells in the ducts. However, these results suggest that most of the migration and redifferentiation in the developing rat parotid gland must be in the opposite direction, i.e., the acinar cells redifferentiate into ductal cells. They also indicate that until there are precise data on the rates of cell death among the several cell types, it remains more appropriate for salivary glands to be categorized as an expanding, rather than renewing, population. © 1995 Wiley‐L

ISSN:0003-276X    

DOI:10.1002/ar.1092410411

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

年代:1995

数据来源: WILEY