摘要:

AbstractBackground: This report provides a detailed description of sinusoidal and perisinusoidal structures in the normal liver of the juvenile Atlantic salmon (Salmo salarL.), a teleost species.Methods: The liver was studied by light, transmission, and scanning electron microscopy, and organ specimens were sampled after retrograde, whole‐body perfusion through the dorsal aorta using 3% glutaraldehyde. Detailed characterization of perisinusoidal stellate cells also included immunohistochemical staining for desmin and evaluation of autofluorescence of the same cells upon excitation in ultraviolet (UV) light.Results: The sinusoid is lined by one cell type only: the endothelial cell. No intraluminal pit cells or Kupffer cells are present. The space of Disse contains reticulin fibres, visualized by Gomori's silver stain, and perisinusoidal stellate cells (PSC). PSC exhibited autofluorescence in UV light, indicating that these cells store vitamin A in cytoplasmic lipid droplets. Immunohistochemically, PSC were found negative for desmin. The space of Disse, extending deep down between adjacent hepatocytes, receives long, slender microvilli from parenchymal cells. In addition to scattered macrophages, interhepatocytic cells (IHC) are found perisinusoidally. Hepatocytes of Atlantic salmon form branching and anastomosing tubules.Conclusions: The sinusoids of Atlantic salmon liver are lined by a fenestrated endothelium, with PSC located in the space of Disse, with macrophages and IHC as inhabitants of the interhepatocytic space. IHC show ultrastructural similarities to mammalian pit cells and teleostean large granular lymphocytes, as well as to piscine monocytes. PSC might be storage cells for vitamin A in Atlantic salmon as shown by autofluorescence in these cells, while immunohistochemical studies indicate that desmin does not seem to be an adequate immunohistochemical marker for PSC in the juvenile Atlantic salmon. Methodologically, fixation for electron microscopy was performed by a new and convenient perfusion method: arterial retrograde whole body perfusion. Liver specimens intended for scanning electron microscopy were fractured at room temperature after prolonged osmium postfixation, leaving hepatocytes intact and producing images well suited to document the three‐dimensional structure of cells and tissue. © 1994 Wiley‐Lis

ISSN:0003-276X    

DOI:10.1002/ar.1092400302

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Recently, collagenous interodontoblastic fibers (IOF) were reported in some particular developmental stages and/or locations of the tooth. However, it remained unclear whether these fibers were identical to so‐called von Korff fibers.Methods: To clarify this issue, we examined the developing mouse molar by three‐dimensional reconstruction of 8 confocal images within a 6 μm‐thick section using laser scanning confocal microscopy, and confirmed our findings using immunoelectron microscopy.Results: In the root pulp during circumpulpal dentin formation, the IOF stained weakly for type I collagen, but stained strongly for type III collagen by a double‐staining technique. It could be clearly seen that many immunoreactive fibers ran spirally among the odontoblasts and entered the predentin. This distribution pattern of IOF was similar to that of the classical von Korff fibers. Furthermore, the existence of anti‐type III reactive collagen fibrils between odontoblasts was confirmed, whereas IOF were not observed in the coronal pulp during circumpulpal dentin formation.Conclusions: This study presents for the first time, immunohistochemical observations which demonstrate the presence of IOF at least during root circumpulpal dentin formation and which reveal that type III collagen is a major component of IOF. © 1994 Wile

ISSN:0003-276X    

DOI:10.1002/ar.1092400303

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Human palmar aponeurosis can be affected by a fibrotic process whose aetiopathology is unknown. As the organization of that normal tissue has not been completely investigaged, the aim of the present study was to define the ultrastructure of the aponeurosis in order to better understand its biology and behaviour in pathology.Methods: Bioptic samples from normal subjects of different ages were analyses by optical and electron microscopy and by immunocytochemistry.Results: The aponeurotic branches consisted of thick, almost parallel collagen bundles containing columns of prominent cells, characterized by long cytoplasmic projections. Cells did not change in number and distribution with age and appeared longer and slighter in the old than in the young subjects. They exhibited plasma membrane almost completely decorated by pinocytic vesicles, intracytoplasmic bundles of thin filaments with zonal thickenings close to the cell membrane, and well‐developed subcellular structures. Cells expressed smooth muscle cell α‐actin, as revealed by immunostaining. The external surface of the plasma membrane was underlined by a discontinuous basement membrane–like structure and by a thick coat of interwoven filaments, highly positive to hyaluronan‐recognizing antibodies. Immunocytochemical analyses revealed that collagen fibrils were positive for collagen types I, III, and VI and that elastin fiber composition was rather complex.Conclusions: Independently of the age, normal palmar aponeurotic cells show peculiar morphological features and peculiar cell‐matrix interactions, very likely mediated by hyaluronan. These findings indicate that normal aponeurotic cells cannot be regarded as typical tenocytes and suggest the need for a better definition of their phenotype in order to understand their behaviour in pathological processes. © 1994 Wile

ISSN:0003-276X    

DOI:10.1002/ar.1092400304

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Ovarian surface epithelial cells have been implicated in the mechanisms of ovulation and development of common ovarian cancers. An early indication of predisposition to neoplasia is the formation of ovarian epithelial inclusion cysts. It was unclear whether morphological alterations along the ovarian surface are related directly to ovulation per se or associated endocrine parameters of reproductive cyclicity.Methods: Light microscopic disturbances in ovarian surface epithelium were monitored during synchronous ovulatory and anovulatory estrous cycles of sheep. Ovulation blockade accompanied by normal luteal phases was induced by administration of indomethacin, a prostaglandin synthase inhibitor.Results: Degenerative cells were sloughed from the apical dome of periovulatory follicles. The resultant stigma of luteinizing follicles was void of surface epithelium. Repair of the ovulatory wound by epithelium did not occur until complete involution of the corpus luteum during the subsequent estrous cycle. In a few cases inclusions containing entrapped ovarian surface epithelium were noted within adjacent stroma. Epithelia covering luteinized unruptured follicles remained intact and was not incorporated into the ovary during luteal resorption.Conclusion: Localized damage to and subsequent remodelling of the ovarian surface occurs in a cyclic fashion conjoined with the physical process of follicular rupture. © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092400305

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Sulfated glycoprotein‐2 (SGP‐2), also designated as clusterin, is a protein secreted by the epididymis and which binds to spermatozoa. In adult rats it is secreted at high levels by principal cells of the distal initial segment, intermediate zone and caput epididymidis, and at relatively lower levels by principal cells of the corpus and cauda epididymidis. The objective of this study was to correlate the developmental events in the maturation of the epididymis with the timing of SGP‐2 expression in order to evaluate the testicular or epididymal factors which may regulate it.Methods: Our approach was to follow and compare the developmental expression of SGP‐2 by immunocytochemistry in normal untreated control rats and rats whose efferent ducts were ligated on day 15 and examined at different postnatal ages thereafter.Results: In control animals, SGP‐2 expression in principal cells of the distal initial segment, intermediate zone, and caput and distal cauda epididymidis, as characterized in normal 90‐day‐old adult animals, was attained between postnatal days 39 and 49. However, only by postnatal day 56 did SGP‐2 display in the corpus and proximal cauda the characteristic secretory pattern found in adult rats. In contrast, in efferent duct ligated rats examined at postnatal day 64, SGP‐2 was absent in principal cells of the corpus and proximal cauda epididymidis but continued to be secreted by the distal initial segment, intermediate zone, and caput and distal cauda epididymidis. Furthermore, unlike the case in control rats, SGP‐2 was secreted at high levels by the principal cells of the proximal initial segment. Thus during normal postnatal development, in the proximal initial segment, the production of SGP‐2 is suppressed by luminal factors originating from the testis, while in the distal initial segment, intermediate zone, and caput epididymidis, it is unaffected by these factors. On the other hand, the production of SGP‐2 in the corpus and proximal region of the cauda epididymidis is normally stimulated by luminal factors originating from the testis, while in the distal cauda, it is unaffected by these factors.Conclusions: Our results thus show a differential regulation of SGP‐2 expression in principal cells of the proximal versus distal regions of the epididymis and even within subdivisions of each region. In some regions of the epididymis, SGP‐2 production appears to be unaffected by luminal factors originating from the testis, while in other regions it is either inhibited or stimulated by these fact

ISSN:0003-276X    

DOI:10.1002/ar.1092400306

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Glutathione S‐transferases (GSTs) are a family of isozymes that catalyze the conjugation of glutathione with various toxic electrophilic compounds. GSTs are composed of several classes based on the degree of sequence homology of their subunits. The Yo subunit, a member of the mu class, is expressed at high levels in the testis and epididymis. The purpose of this study was to immunolocalize the GST‐Yo in these tissues during development.Methods: The testes and epididymides of rats aged 7, 15, 21, 28, 39, 42, 45, 49, and 56 days were fixed in Bouin's fixative, and immunostained for light microscopic analysis.Results: In the testis the cytoplasm of all germ cells was unreactive until day 39. At that time, step 18 spermatids appeared moderately reactive, while the few observed step 19 spermatids were intensely reactive as were their residual bodies. The presence of residual bodies indicates that spermiation takes place as early as day 39; however, the number of step 19 spermatids is low at this age. A progressive increase in the size of the tubule and number of elongating spermatids was seen between days 42 and 49. In addition, by day 49, a weak staining was observed in steps 12–15, moderate in steps 16–17, and intense in steps 18–19 spermatids. In terms of the intensity of staining, cell types stained, size of the tubules, and number of elongating spermatids, no difference was noted between day 49, 56, and adult animals. Thus Yo protein expression in germ cells reached maturity by day 49. The epithelial cells of the rete testis were intensely reactive at day 7 and remained so throughout development. In contrast, while the epithelial cells of the efferent ducts at day 7 were intensely reactive, they were weakly reactive by day 39 and remained so at later ages. Along the entire epididymis, the columnar epithelial cells showed a moderate apical/supranuclear reaction from day 7 to 28. By day 39 principal cells of the initial segment became weakly reactive, while those in the caput and corpus were moderately stained, a situation seen at later ages including adults. Only by day 49 did principal cells of the proximal cauda become moderately stained as seen in adult animals. Thus the expression of the Yo protein in the principal cells of the proximal cauda may be regulated by different factors than those of the caput and corpus epididymidis. Alternatively, the expression of the Yo subunit in principal cells of the proximal cauda may develop later since this region would be the last to receive luminally derived testicular products. In the initial segment, the decrease in staining of principal cells at day 39 may be due to an inhibiting factor emanating from the testis. Spermatozoa appeared in the lumen of each epididymal region well after the expression of Yo had reached its adult staining pattern indicating that they are not a factor.Conclusions: Overall these results suggest that the expression of GST‐Yo in the various cells of the testis and epididymis are controlled by different factors during postnatal development. © 1994 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092400307

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The aim of the present study was to localize, at the fine structural level, a protein found by indirect immunofluorescence to be associated with the mesenchymal tissue (1) closely applied to the intervillus epithelium before the formation of intestinal crypts in the mouse fetus and (2) around intestinal crypts during and after their formation.Methods: We use a pre‐embedding immunolabeling technique for extracellular matrix molecules, and a monoclonal antibody (Mab) directed against antigen MIM‐1/130.Results: Immunofluorescence disclosed the presence of antigen 1/130 in the connective tissue closely applied to the epithelium of the gallbladder, pyloric glands, and intestinal and colonic crypts in adult mice. The antigen was absent in all salivary glands, kidney, liver, lung, spleen, and pancreas. At the fine structural level, gold particles in positive organs were associated with the interstitial matrix around collagen fibrils underneath the epithelia; gold particles were completely absent in the basement membranes. In the small intestine, labeling was seen only around crypts from cell position 1 up to the crypt‐villus junction; it was totally absent under the villus epithelium. In order to confirm this particular localization in vivo, Mab 1/130 was administered orogastrically to 9‐day‐old mice: after 3 hours the antibody was found lining the immediate periphery of duodenal crypts as seen by indirect immunofluorescence. In control animals, an anti‐mouse laminin Mab of the same subclass as Mab 1/130 was orogastrically fed using the same protocol: basal laminae were labeled under the epithelium of duodenal villi and crypts and also in the lamina propria, with a decreasing gradient from the top of the villi to the bottom of the crypts.Conclusion: These observation indicate that the extracellular matrix associated with the epithelium of pyloric glands, of intestinal and colonic crypts, and of gallbladder contains a new antigen whose function remains to be determined. The neonatal mouse hence constitutes a good model to study the role of extracellular matrix components in determining organ differentiation in vivo. © 1994 Wil

ISSN:0003-276X    

DOI:10.1002/ar.1092400308

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Our initial observation of the macroscopically pigmented pineal gland of the big brown bat,Eptesicus fuscus, led to this study. Information has been lacking on pigmentation in the pineal and its significance in mammals in general and bats in particular. This report begins to address this situation.Methods: Bats were examined both in the wild and after exposure to various experimental conditions. The pineals were examined macroscopically as well as with light and electron microscopy. The pigment was identified as melanin by its color, the ultrastructure of its granules, and their reaction with hydrogen peroxide.Results: Gross observations showed the pineals to be variably pigmented, which were subjectively scored from unpigmented to heavily pigmented. Pineals from bats exposed to a continuous 24 h light regimen or those from a summer population contained very little, if any, externally visible melanin. Such pineals are considered unpigmented in this study. In contrast, pineals from 74% of 156 animals taken together, either subjected to constant darkness or hibernation (simulated or natural), exhibited very heavily pigmented pineals. The pigment in these cases even extended to the juxtapineal meningeal covering. The pineal was pigmented even in a newbornEptesicus.Conclusions: The pineal pigmentation in the big brown bat appears to intensify with constant darkness and may vary seasonally. The observation of macroscopically pigmented pineals in some other bats (Myotis lucifugus, Pipistrellus subfiavus, andLasiurus borealis) suggests that this phenomenon may be of taxonomic value for the family Vespertilionidae (Order Chiroptera). © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092400309

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: The paracervical ganglia (PG) are components of the pelvic plexus that provides sensory and motor innervation to the reproductive system of the female rat. Several neurotransmitters including norepinephrine (NE), acetylcholine (ACh), neuropeptide Y (NPY), and vasoactive intestinal polypeptide (VIP) are present in neurons of the adult PG and in axons innervating the adult uterus and uterine cervix. The current study was undertaken to describe the onset of immunoreactivity of these neurotransmitters and neuropeptides during development.Methods: Female rats, ages E18 to P36, were prepared for immunohistochemistry for TH (tyrosine hydroxylase, a marker of noradrenergic neurons), NPY, or VIP as well as the histochemical demonstration of acetylcholinesterase (AChE).Results: All four markers were detected in neurons of the PG at E18. Changes in the appearance of these markers from E18 to P36 reflected previously described growth changes in the PG. Axons containing AChE, TH, NPY, or VIP were first detected within the cervix at E20. Immunopositive axons first appeared as thick, unbranched structures at the outermost portion of the cervical myometrium. Over time, these axon bundles ramified to form discrete varicose axons. The ingrowth was similar for axons containing each of the four markers.Conclusions: The relative density of each neuronal type in the PG was reflected in the density of axons containing the same marker in the cervix. Changes in neurotransmitter/neuropeptide staining of PG neurons or axons in the cervix were not observed as the animals approached puberty. © 1994 Wiley‐Liss, I

ISSN:0003-276X    

DOI:10.1002/ar.1092400310

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

年代:1994

数据来源: WILEY

摘要:

AbstractBackground: Mesenchyme‐like macrophage (M) precursors called angular cells are present in rat lungs on the thirteenth day of gestation and by then can differentiate into outright macrophages. Based on studies of bone marrow–derived cells, it is widely believed that the macrophage line necessarily proceeds from a colony‐forming unit with dual granulocyte‐macrophages potential (CFU‐GM). In embryos this seems doubtful since macrophages are already scattered throughout the body before the first granulocytes appear. We examined the question in organ cultured 14 day prenatal rat lungs after having shown earlier that the macrophage population developed in explants is increased by exposure to M‐ and GM‐colony‐stimulating factors (CSFs) but is unaffected by multi (IL‐3)‐ or granulocyte (G)‐CSF. Reportedly retinoic acid (RA) shifts CFU‐GM strongly to wards granulocytic differentiation and inhibits mitosis of unipotential macrophage precursors but not differentiated cells. Transforming growth factor β1 (TGF) inhibits multipotential blood progenitors but allows proliferation of committed precursors, and TGF together with GM‐CSF induces granulocytopoiesis from CFU‐GM.Methods: Lung pairs were grown on a serum‐containing medium or one supplemented either by RA, TGF, or TGF/GM‐CSF to form a control and three experimental groups. A fourth experiment compared responses to M‐CSF exposure and M‐CSF/TGF. Macrophage population growth was estimated by measuring the areas of coronas formed by macrophages emerged from the explants. F‐actin was stained with florescein‐labeled phalloidin.Results: In all experiments macrophages were produced unmixed with granulocytes. By +8 days they had largely emerged to form coronas about the lungs. In cultures exposed to RA, macrophages were less intensely stained for actin and slower to emerge than controls. At +8 days, however, coronal areas were not significantly different from controls, as was also true for the TGF group. In contrast, coronal areas of cultures grown with TGF/GM‐CSF were much larger. At +17 days, mean coronal area of TGF cultures was about half that of controls (P<0.05), whereas mean coronal area of the TGF/GM‐CSF group was 5.4 times greater (P<0.001). Macrophages from control and TGF‐exposed cultures responded to M‐CSF by an increase in coronal area which was greater among cultures given M‐CSF alone than those given TGF + M‐CSF (bothP<0.005).Conclusions: Macrophage precursors in embryonic lu

ISSN:0003-276X    

DOI:10.1002/ar.1092400311

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

年代:1994

数据来源: WILEY