摘要:

AbstractBackground: Cadherins are transmembrane proteins mediating calcium‐dependent cell–cell adhesion in a cell type‐specific manner by means of homophilic binding. M(muscle)‐cadherin is a recently detected member of the cadherin family.Methods: We have investigated the localization of M‐cadherin innormal and aneurally regenerating skeletal muscle of rat by means of pre‐embedding immunocytochemistry. The antibody was directed against the extra‐cellular domain of M‐cadherin.Results: Myoblasts and myotubes in regenerating muscles tended to be arranged in clusters enclosed by a common basal lamina. Satellite cells of mature muscle fibers were attached to the underlying fiber without separating basal lamina. Reactivity for M‐cadherin was restricted to the plasma membranes of myoblasts and satellite cells, and was most intense at the membrane areas facing adjacent myotubes or myofibers. Myoblasts interposed between two myotubes were stained on the entire surface. The adjacent plasma membrane of the otherwise negative myotube or muscle fiber, was stained as well, and extracellular reaction product was in the gap between the cells.Conclusion: The cellular localization of M‐cadherin may indicate that M‐cadherin is involved in calcium‐dependent adhesion between satellite cells and muscle fibers or, by means of interposed myoblasts, between the clustered myotubes in a regenerating muscle.

ISSN:0003-276X    

DOI:10.1002/ar.1092390202

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Silver‐stainability (argentophilia) of cytoplastmic structures occurring in spermatids have been localized into the organizing perinuclear theca, but the biochemical nature and structural associations of these proteins with the cytoskeletal and membranous elements are unresolved and, therefore, were the aim of the present study.Methods: Light and electron microscopic analysis of the silver‐stainability in the rat spermatids and spermatozoa was carried out in the intact testis tissue and epididymal spermatozoa and after their chemical and mechanical extraction. Correlation of argentophilia with specific proteins of rat and bovine spermatids and spermatozoa was investigated using a recently developed technique for silver nitrate staining of proteins on nitro‐cellulose.Results: Sequential formation of the silver‐stainable domains seemed to proceed from the argentophilic acrosomal ring. Various extractions indicated that argentophilia in the spermatids and spermatozoa was mainly associated with the perinuclear theca and to some extent to the plasma membrane. Hyamine‐soluble extract from spermatozoa of rat and bull revealed only a single argentophilic protein of 130 kDa. Hyamine and SDS‐soluble extracts of rat testis tissue contained an additional group of argentophilic polypeptides of lower molecular weight (115, 94, 36, 23, and 21 kDa).Conclusions: Reduction in the number of argentophilic proteins appears to be involved in a series of changes in the cyto‐architecture of developing spermatids. Tentative cytoskeletal nature of argentophilic proteins remains to be identified. Nevertheless, they may have important physical relations with the higher‐order organization of the sperm head cytoskeleton and overlying membranes. © 1994

ISSN:0003-276X    

DOI:10.1002/ar.1092390203

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The zona pellucida (ZP), an extracellular matrix which surrounds mammalian oocytes, is formed by different glycoproteins. Several studies have revealed that carbohydrate residues present in glycoproteins of ZP play a key role in the sperm‐egg recognition. However, the origin and the biochemical composition of ZP remain to be completely resolved.Methods: ZP glycoproteins from rat ovarian follicles were investigated at light and electron microscopic level by the application of lectins conjugated to peroxidase, digoxigenin, and colloidal gold in combination with enzyme and chemical treatment. A quantitative analysis was also performed.Results: ZP shows reactivity to WGA, DSA, LFA, AAA, RCA I, and MAA. SBA and PNA showed a variable reactivity ranging from negative to strongly positive. A uniform pattern of binding throughout ZP was observed with DSA, Con A, AAA, MAA, and LFA. However, labeling by RCA I and SBA was higher in the outer ZP while PNA and WGA showed a higher binding in the inner ZP. Lectin reactivity was detected in cortical granules, endoplasmic reticulum, Golgi apparatus, vesicles, and multivesicular bodies of oocytes.Conclusions: ZP contained the terminal disaccharides Galβ1,4GlcNAc, Galβ1,3GalNAc, and GalNAcβ1,3Gal and the trisaccharides Neu5Acα2, 3Galβ1,4GlcNAc, Neu5Ac‐Galβ1,3GalNAc, and Neu5Ac‐GalNAcβ1,3Gal sequences. The occurrence of Fucose residues α 1,6 linked to the inner core region of N‐linked glycoproteins of ZP was demonstratd by the use of several fucose‐specific lectins. Methylation‐saponification treatment in combination with lectin cytochemistry reveals that Gal, GalNAc, and polyllactosamine residues of rat ZP glycoproteins contain sulphated groups. The reactivity observed in ooplasmic vesicles was similar to that of ZP, thus suggesting that the oocyte is the site of synthesis of ZP glycoproteins. ©

ISSN:0003-276X    

DOI:10.1002/ar.1092390204

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Numerous studies have described the anatomy of the large lymphoid aggregates of bronchus‐associated lymphoid tissue (BALT) in rabbits and rats. Less work has been performed on other immunocompetent areas of the respiratory tract, and available data again mostly describe rabbit or rat tissues. Little is known therefore of the microanatomy of the mouse lung immune system.Methods: We report a study, devised in order to establish the immunohistological characteristics of normal healthy mice lungs, performed on whole lungs from 22 mice of various strains and/or ages. Snap frozen tissues were serially sectioned and analysed using histochemistry and immunohistological techniques. Scattered macrophages, IgA plasma cells, B and T cells were enumerated in each sample.Results: The largest population was that of macrophages. B‐cells were numerous in all mice but 3 adults. T‐cells were always present, L3T4+ often more numerous than Lyt2+ cells. Small lymphoid aggregates, composed of B or T cells (L3T4+ and Lyt2+) were seen in all mice, in the vicinity of a bronchiole and a vein. In 12/22 mice, a peculiarly elongated para‐esophagal lymph node with large peripheral B‐cell nodules and medullary T‐cells was observed. In the five strains of mice studied, large variations were noted, affecting all the cell types studied, and related either to age or strain.Conclusion: Besides providing a qualitative description and quantitative analysis of immunocompetent cells, this work reports age and strain‐related variations in these cells' distribution. These data could be relevant for studies involving the analysis of mice respirtory immune responses to environmental antigens. © 1994 W

ISSN:0003-276X    

DOI:10.1002/ar.1092390205

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Neuro‐epithelial bodies (NEB) are corpuscles of currently equivocal function which are present in the lungs of vertebrates. Comparative studies may help to elucidate their role.Methods: The NEB ofBasiliscus vittatus(Reptilia, Iguanidae), a terrestrial lower vertebrate able to dive, are for the first time examined by electron microscopy, immunocytochemistry, and for argyrophilia.Results: Most NEB contain both immunoreactive calcitonin and serotonin but are not labelled with argyrophilia or immunocytochemistry against calcitonin gene‐related peptide (CGRP), protein gene product 9.5 (PGP 9.5), or the Leu‐7 epitope (Leu‐7). Therefore, in NEB of this species, the transcription of the calcitonin/CGRP gene exclusively favors the expression of calcitonin and this is in contrast to the intrapulmonary small neurons. Also, a physiologic difference is expected in the metabolism of ubiquitin in NEB ofB. vittatusvs. mammalian NEB and neurons. In addition, the NEB cells are always covered by at least a thin cytoplasmic extension of a neighbouring cell, indicating that luminal contact is not required. Stronger still, it appears that in some lower vertebrates contact to the airspace is avoided. Finally, we provide ultrastructural evidence for the basket‐like innervation of NEB in some reptiles. This way of innervation possibly represents an evolutionarily different concept for interaction between NEB corpuscular cells and nerve fibers.Conclusions: Beyond the confirmation that morphology, content of biologically active substances such as serotonin and calcitonin, and innervation are evolutionary well preserved features of NEB, the results reveal some intriguing features ofB. vittatusNEB: strict separation of calcitonin and CGRP, reduced need for the de‐ubiquitinating enzyme PGP 9.5, lack of luminal contact, and the basket‐like innervation. The latter two properties possibly refer to a mechanoreceptor function of NEB in this species. © 1994 W

ISSN:0003-276X    

DOI:10.1002/ar.1092390206

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The cardiac neural crest (neural crest extending from the mid‐otic placode to the caudal region of somite 3) provides ectomesenchymal cells that contribute to aortic arch development and are essential for aortico‐pulmonary septation of the outflow tract. Bilateral ablation of the cardiac neural crest in the chick embryo, prior to migration, leads to aortic arch anomalies and failure of septation of the cardiac outflow tract, which produces a severe defect known as persistent truncus arteriosus (PTA). Altered hemodynamics resulting from abnormal aortic arch artery development and PTA and other unknown factors related to the absence of neural crest, are likely to alter the developmental history of the myocardium.Methods: In this study the wet and dry weights of ventricles and whole embryos, the total number of myocytes per ventricle and the myocyte density (number of myocytes per unit volume of ventricular myocardium) were compared in control (unwindowed eggs), sham‐operated and cardiac neural crest ablated chick embryos at day 11 of incubation.Results: We found that the wet and dry weights of ventricles from hearts with PTA were not different from normal hearts in control and sham‐operated embryos. However, the embryos with PTA weighed less than embryos with normal hearts. Thus, the ventricle to embryo weight ratios were greater in embryos with PTA compared to control and sham‐operated embryos for both wet (14 and 20%, respectively) and dry (30 and 59%) weights. The data further implied that more water was present with respect to body weight in comparison with sham‐operated and control embryos which indicated that the embryos with PTA were edematous. The total number of myocytes and the number of myocytes per unit volume were not different when comparing sham‐operated with PTA. Further, there was no indication that the myocardium from hearts with PTA was abnormal despite the small size and edema of the embryos.Conclusions: It appears that hemodynamic stresses, resulting from the structural defects produced by neural crest ablation, are insufficient to increase heart growth, although cardiac function is depressed as evidenced by edema and failure of the embryo to thrive. © 1994 W

ISSN:0003-276X    

DOI:10.1002/ar.1092390207

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Ultrastructural studies of growth hormoneproducing cells (GH cells) in the anterior pituitary gland have been reported using several experimental animals. However, no attempt has yet been made to identify the ultrastructural heterogeneity of the GH cells within the human anterior pituitary gland. To this end, we employed immunogold electron microscopy to investigate the ultrastructural characteristics of GH cells in relation to gestational age in normal human fetuses.Materials: Based on ultrastructural characteristics, three distinct types of GH cells were identified by immunogold electron microscopy in the anterior pituitary glands of 34 normal human fetal pituitary glands. The age of the tissue samples ranged from 8 to 34 weeks.Results: The Type‐I GH cell is a small, round cell with a narrow cytoplasm containing a few small secretory granules (268 nm in mean diameter). The GH cells designated Type‐II are polygonal and contain medium‐sized secretory granules (347 nm), profiles of rough endoplasmic reticulum (RER) arranged in parallel lamellae, and a Golgi complex which is frequently encountered but only in this cell type. The Type‐III GH cell is polygonal, large, and contains numerous large spherical‐shaped secretory granules (404 nm). The Type‐I was the predominant cell type until about 20 weeks of gestation; its incidence decreased thereafter. In contrast, the Type‐II and Type‐III cells increased in number starting at 20 weeks of gestational age.Conclusion: From these results, we suggest that Type‐I is the most immature type of GH cell, Type‐III the most mature, and the Type‐II is intermediate in development. The marked difference in the incidence of each GH cell type between the first and second half of gestation appears to be a reflection of the development of the hypothalamic regulation of the anterior pituitary gland, which is reported to be established at around 20 weeks of gestation.

ISSN:0003-276X    

DOI:10.1002/ar.1092390208

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackgrouns: Since its initial discovery in the avian intestine, calbindin‐D28khas been reported to occur in various species and tissues. Although calbindin‐D28kbinds calcium ions in the physiologically relevant range of intracellular calcium, its functional role in the various cell types where it has been localized remains unknown.Methods: We examined the occurrence of calbindin‐D28kin the brain and kidney of the testudine reptile,Trachemys scripta, by immunoblotting and immunocytochemistry using rabbit anti‐sera directed against rat renal calbindin‐D28kand chicken intestinal calbindin‐D28k.Results: Immunoblotting revealed the presence of calbindin‐D28kin the turtle tissues. A single immunoreactive band in the 28,000 relative molecular mass region was visualized in cerebellar and renal homogenates. Immunocytochemistry revealed reaction product for the presence of calbindin‐D28kin the Purkinje cells of the cerebellum, and in the distal tubular cells of the nephron. Processes as well as the perikaryon of the Purkinje cell were immunoreactive.Conclusion: This study describes the occurrence and cellular localization of calbindin‐D28kin a reptilian cerebellum, and confirms the phylogenetic distribution of renal calbindin‐D28kto the oldest major reptilian group. ©

ISSN:0003-276X    

DOI:10.1002/ar.1092390209

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Renin‐containing (RC) cells in small ruminant kidneys have been known to be widely distributed along the blood vessels. In the present study, RC cells in developing sheep kidneys were studied to investigate not only the appearance but distribution with the potential physiological significance using immunohistochemical and histophanimetrical techniques.Methods: Seven fetal, 12 newborn, and 3 adult metanephric kidneys were used and immunostained by anti‐renin antiserum. In the histoplanimetrical analysis, the numerical values of RC cells existing at the walls of 3 major arterial types in the kidneys were calculated.Results: At day 44 of gestation, RC cells were already demonstrated in the walls of renal, interlobar, and afferent vessels, located in the deep cortex and the medulla. In intermediate gestational periods, RC cells were detected throughout the intrarenal arterial trees. In late gestational periods, RC cells expressed in the walls of interlobar/arcuate and interlobular arteries tended to decrease or disappear gradually, while they were distributed predominantly in the afferent glomerular vessels. In newborn lambs, especially days 1 to 3 after birth, increased numbers of RC cells were demonstrated throughout the arterial trees in the kidneys. In older lambs, RC cells located in the interlobar/arcuate arteries and the proximal region of the interlobular arteries decreased in number and gradually disappeared. Some RC cells were still distributed in the distal portion of the interlobular artery even in the adult sheep.Conclusions: These results suggest that the wide distribution of RC cells in sheep kidney is formed in perinatal life, and that the neuronal regulation is associated with the maintenance of this distribution. © 1994 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092390210

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Although it is known that deer antlerogenic potential resides in the periosteum of an antlerogenic region and antler forms through modified endochondral ossification, how a deciduous antler forms histologically through a permanent pedicle from the periosteum has not been reported.Methods: Histogenesis of the pedicle and the early first antler in red deer was systematically examined using light microscopy techniques.Results and Conclusions: At the pre‐pedicle stage, the frontal lateral crest (under 5 mm in height) consisted horizontally of antlerogenic periosteum and underlying cancellous bone. Both the cellular layer (3.74 times,P<0.01) and the fibrous layer of the antlerogenic periosteum were much thicker than those of the margin of the antlerogenic region or the facial periosteum. The crest was formed through intramembranous ossification. When the pedicle began to develop (5–15 mm in height), some discrete clusters of mature chondrocytes appeared in the bony trabeculae, which signified the beginning of the transition of the ossification pattern from the intramem branous to the endochondral. The pedicle consisted of three portions from distal to proximal, periosteum/perichondrium, osseocartilaginous tissue, and osseous tissue. When the pedicle became visible (about 20 mm in height), it consisted of the same three portions as the pedicle initiation stage, but the osseocartilaginous portion was expanded compared to the initiation stage and the cartilaginous proportion increased distally. When the pedicle grew to 25–40 mm in height, continous cartilaginous trabeculae appeared under the apical perichondrium. The pedicle consisted of four portions from distal to proximal: perichondrium, cartilaginous tissue, osseocartilaginous tissue, osseous tissue. It was formed through endochondral ossification. All these ossification pattern changes could not be seen externally as the overlying integument was characterised by typical scalp skin. When the pedicle grew to about 60 mm in height, antler tissue was visually apparent at the apex as the hair type changed from scalp hair to the velvet‐like hair of growing antler. However, this transformation could not be distinguished internally as the inside tissues were all continuous between pedicle and antler. Therefore, the histogenesis of the deer pedicle and the first antler originated from the antlerogenic cells and covered two phases: an internal phase through which pedicle was formed and an external phase which signalled the beginning of antlerogenesis. © 1994 Wiley

ISSN:0003-276X    

DOI:10.1002/ar.1092390211

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

年代:1994

数据来源: WILEY