摘要:

AbstractImmunoreactivity to serotonin was observed in Merkel cells as well as the afferent type I nerves terminating upon them in touch domes excised from the belly skin of rats. Type I nerves were strongly immunoreactive and could be traced through the dermis of the domal papilla. Merkel cell immunoreactivity was sometimes seen in the entire cell, but was often localized in the Merkel cell cytoplasm adjacent to nerve terminals and may have been in the terminals themselves. Domes were fixed by immersion in 4% paraformaldehyde‐lysine‐sodiumm‐periodate (PLP) fixative at 4°C for 2.5–3 hours and cryoprotected in 30% sucrose overnight. Sections were processed with the avidin‐biotin complex peroxidase (ABC), peroxidase‐antiperoxidase (PAP), and indirect immunofluorescence techniques with rabbit antiserum generated again

ISSN:0003-276X    

DOI:10.1002/ar.1092320112

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

年代:1992

数据来源: WILEY

摘要:

AbstractThe bursa of Fabricius was studied by immunohistochemical method using anti‐vimentin monoclonal antibody (clone 3B4). This monoclonal antibody indentified a vimentin positive cell in the medulla of the bursal follicle. During the first 2 weeks of life the vimentin positive cells located along the corticomedullary border and later became prominent in the medulla with the exception of a narrow zone adjacent to the corticomedullary border. After hatching the accumulation of vimentin‐type intermediate filaments on one side of the nucleus endowed the vimentin positive cells with a polarized appearance. This “cap‐like” vimentin positive area of the cytoplasm determined the position of the major cell process. Within the medulla the Ia positive secretory dendritic cells contained secretory granules in one of the cell processes. The distribution, shape, and polarized appearance of the vimentin positive cells were identical with that of the secretory dendritic cells. Therefore, the anti‐vimentin monoclonal antibody proved to be useful for identification of the bursal secretory dendritic cells. During rapid bursal growth the number of secretory dendritic cells increased, possibly, by proliferation of vimentin negative secretory dendritic cell precursors located along the corticomedul

ISSN:0003-276X    

DOI:10.1002/ar.1092320113

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

年代:1992

数据来源: WILEY

摘要:

AbstractIn the horse, several thousand lymph nodes receive lymph from the intestine, part of which is very large and contains microorganisms that enable the animal to utilize refractory dietary constituents such as cellulose. The aim of this study was to describe the pathways by which lymph is delivered into, traverses, and is drained from these lymph nodes. These pathways were studied with either Microfil or methacrylate casting materials and with light and electron microscopy.The afferent lymphatic vessel delivering lymph into one of the nodes divides over the capsular surface and within trabeculae into terminal branches, and these are continuous with the subcapsular and trabecular sinuses through rounded holes up to 30 μm across.Lymph is conveyed from the subcapsular and trabecular sinuses through the cortex by four types of sinuses: trabecular sinuses, cortical tubular sinuses, tubulelike sinuses with a network of stellate cell processes, and sinuses between cortical cords. It is conveyed through the medulla by sinuses both within and between medullary cords.Lymph is drained from these sinuses by initial efferent lymphatics of three types: those between medullary cords, those within the subcapsular sinus overlying medullary or cortical cords, and those within trabeculae. All three types are continuous with surrounding sinuses through holes 5–30 μm across. These three alternative routes for lymph drainage may ensure adequate lymph flow during different intranodal conditions that may exist when the node is responding to microcrganisms or other foreign materi

ISSN:0003-276X    

DOI:10.1002/ar.1092320114

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

年代:1992

数据来源: WILEY

摘要:

AbstractMaternal administration of glucocorticoids is known to stimulate fetal lung maturation. In the present study, we used microscopy and stereology to evaluate the morphological effects of maternal glucocorticoid treatment on rabbit fetal lung tissue. Betamethasone was administered to pregnant rabbits on days 25 and 26 of gestation at a dose of 0.2 mg/kg body weight. The animal were sacrificed on day 27 of gestation. Glucocorticoid treatment significantly increased the presumptive airspace in the fetal lung tissue but did not alter the relative proportion of epithelium, connective tissue, or vasculature in the tissue. In addition, glucocorticoid treatment significantly increased the proportion of type II cells in the prealveolar epithelium, increased the rate of phosphatidylcholine synthesis, and increased the content of the major surfactant‐associated protein, SP‐A, in the fetal lung tissue. We could detect no effect of betamethasone on lamellar body crosssectional area, numerical density, or volume density within fetal lung type II cells. Glucocorticoid treatment of the pregnant doe caused a decrease in the volume density of intracellular glycogen and an increase in the volume density of mitochondria in fetal lung type II cells. Betamethasone treatment did not alter the distance between fetal lung epithelial cells and subadjacent connective tissué cells. However, glucocorticoid treatment increased the number of connective tissue foot processes that pierced the epithelial basal lamina. Thus, glucocorticoid treatment of the pregnant doe results in structural changes in the fetal lung tissue, an acceleration of some aspects of type II cell defferentiation, and a concomitant increase in epithelial‐mesenchymal intera

ISSN:0003-276X    

DOI:10.1002/ar.1092320115

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

年代:1992

数据来源: WILEY

摘要:

AbstractImmunocytochemical techniques were used to study the distribution of fibronectin, type IV collagen (collagen‐IV), and laminin in four different stages of mouse blastocyst development. Immunoreactivity for collagen‐IV and laminin is present in a granular pattern inside the inner cell mass (ICM) cells in stage 1 blastocysts, while these blastocysts are negative for fibronectin. Fibronectin immunoreactivity appears extracellularly under the trophectoderm (TE) in stage 2 blastocysts, in the form of homogeneously distributed dots, and/or fibrils located preferentially close to cell boundaries. It is followed by the appearance of both collagen‐IV and laminin immunoreactivity in patches on the basal side of the TE in stage 3 blastocysts. These patches are initially localized under the central region of TE cells, thus in a location clearly different from that of fibronectinpositive fibrils. As development proceeds the collagen‐IV‐ and laminin‐positive patches become larger, covering, by stage 4, an extensive portion of the inner lining of the blastocoel. Fibronectin‐positive material is still present in a fibrillar form in stage 3 blastocysts, but is generally reduced to thin strands by stage 4. These results indicate that fibronectin is independent of the mouse blastocyst basement membrane, but may play a transient role in cell adhesion during its deposition. In addition, the results suggest that the ICM plays a major role in the production of collagen‐IV and laminin, while the basal surface of TE cells is the primary site of basement me

ISSN:0003-276X    

DOI:10.1002/ar.1092320116

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

年代:1992

数据来源: WILEY

摘要:

AbstractCetaceans possess cryptic testes that lie within the abdominal cavity, that are surrounded by primary locomotor muscles, and that are presumably exposed to core or above core body temperatures. It has remained a question as to how cetaceans produce and store viable sperm at these high temperatures. We offer anatomical evidence for a two layer arterio‐venous countercurrent heat exchanger at the cetacean testis. Subcutaneous veins from the peripheral surfaces of the dorsal fin and flukes carry cool blood from the fins to the lumbo‐caudal venous plexus. The lumbo‐caudal venous plexus is juxtaposed to the spermatic arterial plexus, which supplies the testis. Venous plexus flow is from the ventro‐lateral margins of the visceral cavity towards the vena cava. Arterial plexus flow is from the aorta towards the ventro‐lateral margins of the visceral cavity and into the testis. The existence of a countercurrent heat exchanger suggests that cetaceans potentially compensate for detrimental effects of core temperatures on sperm viability and storage by regulating the temperature of blood flow to t

ISSN:0003-276X    

DOI:10.1002/ar.1092320117

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

年代:1992

数据来源: WILEY

摘要:

AbstractSeveral radiographic techniques for estimating bone cross‐sectional geometric properties of mandibular corpora are compared. A hollow symmetrical model significantly improves estimates compared to solid or hollow symmetrical models that have been used in previous studies. Using this model, biplanar radiographs can give sufficiently accurate information of the amount and distribution of cortical bone in a section given relatively regular subperiosteal and endosteal perimeter

ISSN:0003-276X    

DOI:10.1002/ar.1092320118

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

年代:1992

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1092320101

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

年代:1992

数据来源: WILEY