摘要:

AbstractAn interfollicular smooth muscle that spans the triad of hair follicles has been identified in the skin of the domesticated pig (Sus scrofa). This muscle has been previously noted by other investigators and identified as an arrector pili muscle. However, it cannot be interpreted as such for the following reasons: (1) It lies opposite the arrector pili muscle on the follicle; (2) the orientation of its fibers is perpendicular to those of the arrector pili; (3) the two muscles are not continuous; their attachments are different; and (4) contraction of the interfollicular muscle would have little effect on erection of the hairs. Based on structural evidence, it is postulated that upon contraction the muscle draws the base of the three aligned follicles together into a triangular conformation. In so doing, it may rotate the outer two follicles of the triad. Its specific functional role is unknown.

ISSN:0003-276X    

DOI:10.1002/ar.1092010302

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe frequency of satellite cells was quantitated by electron microscopy in five proximal to distal regions of the soleus muscle of adult mice. In all, 236 satellite cell nuclei and 4,475 myonuclei were counted on 51 transverse thin sections. The mean percentage of satellite cells, as a ratio of satellite cells to myonuclei, per region was found to be 5.4%, 5.3%, 5.0%, 5.2% and 4.9% for the most proximal to distal areas, respectively. Analysis of variance revealed no significant differences between either the regions or the animals studied. The number of satellite cell nuclei per cross‐sectional area of muscle was also calculated for each of the five regions, and these values did not vary significantly from the proximal to distal ends of the muscle. Despite the fact that satellite cells were frequently noted in close association with cross‐sectional profiles of myoneural junctions, this study establishes that the number of such perisynaptic satellite cells was not large enough to affect significantly the mean percentages of all satellite cells counted within the motor endplate regions (areas 3 and 4) of the soleus muscle. It is concluded from this study that satellite cells are uniformly distributed throughout the whole mus

ISSN:0003-276X    

DOI:10.1002/ar.1092010303

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

年代:1981

数据来源: WILEY

摘要:

AbstractAxons in the rat molar pulp have been examined morphometrically to determine axonal size and the degree of axonal exposure and axoaxonal apposition in tissue fixed by perfusion using 2% glutaraldehyde in cacodylate buffers ranging in molarity from 0.025 M to 0.4 M. Between 31.2% and 45.0% of the axons were incompletely ensheathed. This proportion of axons exposed was linearly related to the buffer molarity (P<0.05) and was approximately double that found in more central axons. Between 32.3% and 45.0% of the axons were in contact with other axons. This proportion was not linearly related to buffer molarity but was at least ten times higher than that observed in more centrally positioned nerve fibers in the inferior alveolar nerves. Increasing buffer molarity reduced the size of the axons, a relationship not found in the more central axons. It is suggested that axonal exposure and axoaxonal apposition are constant, significant features of pulpal nerve fibers that may be related to the onset and spread of nociceptive activity. The permeability properties of pulpal axons may differ from those of more centrally placed axons.

ISSN:0003-276X    

DOI:10.1002/ar.1092010304

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe clear cell is a characteristic cell type, particularly frequent in the epididymal tail, which has many small vesicles and larger vacuoles in the apical cytoplasm. In freeze‐fracture replicas of adult rat epididymis, we found that the limiting membrane (P‐face) of these vesicles and vacuoles, as well as the luminal plasma membrane (but not the basolateral membrane) contain a high density of prominent intramembrane particles. In contrast, the apical vesicles of the most common cell type, the principal cell, have a much lower density of particles, which are also of smaller size. The unique organization of these membranes in clear cells suggests that this cell type has a special role in epididymal funct

ISSN:0003-276X    

DOI:10.1002/ar.1092010305

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe ovaries of many mammals lie within membranous sacs called bursae ovaricae. In this study, we have examined the morphology of the bursa surrounding the hamster ovary using light and electron microscopy. The bursa is composed of three layers: (1) an inner, discontinuous bursal epithelium that faces the ovary; (2) a middle layer of connective tissue that contains fibroblasts, bundles of smooth muscle cells, and blood vessels; and (3) an outer, continuous epithelium that faces the peritoneal cavity. One side of the bursa has a thin layer of connective tissue, and because the ovary may be seen through it, we refer to this region of the bursa as the “window”. Elsewhere a thick layer of fat joins the connective tissue and blocks visualization of the ovary. Tracers (Evans blue and lanthanum) applied to the peritoneal surface do not penetrate beyond the peritoneal epithelium. Tracers injected into the bursal cavity penetrate all layers of the bursa, but do not pass through the peritoneal epithelium. Therefore, the bursa prevents tracer exchange between the bursal and peritoneal cavities, but exchange does take place between the bursal cavity and blood vessels within the bursa. We suggest that bundles of smooth muscle cells within the bursa may serve to regulate fluid volume and pressure within the bursal cavity. Possible functions of the complete bursa in the hamster are discus

ISSN:0003-276X    

DOI:10.1002/ar.1092010306

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

年代:1981

数据来源: WILEY

摘要:

AbstractAutologous SMG fragments were implanted in tongues of male rats which were sacrificed 15–20 min, 24 hr, 72 hr, 1 week, or 8 weeks after implantation. The tongues were excised, fixed, and processed for light and electron microscopy. In addition, some rats were injected with [3H]‐thymidine 1 hr before sacrifice and the labeling indices (L.I.) of the salivary epithelial and interstitial cells were calculated. Twenty‐four hours after implantation, SMG autografts showed massive central necrosis with some acini and ducts surviving at the periphery of the lobules. There was marked infiltration of the autografts with neutrophils and macrophages. Also the basal laminae surrounding the necrotic acini and ducts remained intact. The morphology of the autografts after 72 hr was similar to that after 24 hr except that there was additional necrosis and acini and ducts could no longer be identified in the autografts. By 1 week after implantation, the autografts showed lobular morphogenesis, ductal branching, and revascularization. At this time, the regenerating salivary epithelium appeared undifferentiated with no evidence of secretory granules. The L.I. of interstitial and ductlike structures showed significant increases over control values at 1 week after implantation, and then declined toward control levels by 3 weeks after implantation. By 8 weeks after implantation, there was evidence of acinar and striated ductal cytodifferentiation in two autografts. The results emphasize the potential of SMG autografts to regenerate subsequent to severe tissue nec

ISSN:0003-276X    

DOI:10.1002/ar.1092010307

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

年代:1981

数据来源: WILEY

摘要:

AbstractNerve terminal‐smooth muscle relationships were studied in pulmonary arteries of the cat using 5‐hydroxydopamine to help differentiate adrenergic and nonadrenergic terminals. There was a periarterial plexus of nerves in the walls of pulmonary arteries that extended into the lung to innervate even small arteries having a single layer of smooth muscle cells. Adrenergic nerves surrounded all arteries and extended into the tunica media of the large arteries. There were also apparent cholinergic nerves around the pulmonary arteries, although this was confirmed by electron microscopy for medium‐ and small‐sized arteries only. The relationships of nerve terminals to smooth muscle cells in pulmonary arteries suggest that release of norepinephrine by adrenergic terminals can produce both decreased compliance and increased resistance in the pulmonary vascular bed, and that acetylcholine released by cholinergic terminals may act directly on vascular smooth muscle or on adrenergic terminals to modulate release of norepinephrine. These results suggest that both sympathetic and parasympathetic nerves may have a regulatory role in the pulmonary circ

ISSN:0003-276X    

DOI:10.1002/ar.1092010308

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

年代:1981

数据来源: WILEY

摘要:

AbstractA single endotracheal instillation of elastase initiates a series of changes in animal lungs that results in a condition resembling human panlobular emphysema. An ultrastructural examination of this series of changes was conducted on the lungs of male golden hamsters exposed to3H‐methylated pancreatic elastase and sacrificed at intervals between 4 hour and 24 days after exposure to enzyme.Lung tissue between 4 and 48 hours showed evidence of hemorrhage and progressive degradation of elastic fibers. Very little indication of epithelial cell damage accompanied these changes. Four days after exposure to elastase, synthesis of new elastic fibers began with the appearance of small clumps of microfibrils in close association with interstitial cells, fibroblasts, and smooth muscle cells. There was also evidence of alterations in alveolar type II cells at this time. Small fibrillar elastic fibers continued to be present in the lung through twenty‐four days and may represent a slow repair process or may indicate a structural difference in elastic fibers synthesized after exposure to elastase. Evidence of the continued degradation of elastic fibers could be found up to 16 days after exposure to elastase, revealing that repair processes were occurring in some areas of the lung while destructive processes still predominated in other ar

ISSN:0003-276X    

DOI:10.1002/ar.1092010309

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

年代:1981

数据来源: WILEY

摘要:

AbstractRat adrenals in different states of stimulation were examined by transmission electron microscopy following perfusion fixation using an in situ isolated‐circulation technique. In unstimulated glands, intracortical capillaries were constricted and the cells of the cortex were pressed closely together with little development of filopodia or intercellular spaces. Glands fixed during the period of operative stress, or following a 1 hr perfusion with Adrenocorticotropic hormone (ACTH) showed that the radially orientated capillaries of the cortex were massively expanded, and the cells of both the glomerulosa and fasciculata exhibited an extensive development of filopodia on their surfaces. These filopodia extended into enlarged intercellular spaces, where they often entered into complex relationships with filopodia from neighboring cells.The development of filopodia by cells of the adrenal cortex was also observed using scanning electron microscope techniques. In cells either icubated with ACTH in vitro or isolated from adrenals of rats treated with ACTH in vivo, the filopodia were numerous, often branched, and could reach as much as 1 μm in length. In contrast, adrenal cells obtained from animals pretreated with cortisol were smooth surfaced.Other cell characteristics, including mitochondria, smooth endoplasmic reticulum, dense granules, and coated vesicles did not show such dramatic correlations with the state of stimulation. It is considered that the development of filopodia and intercellular space is related to secretory mechanisms in the rat adrenal cort

ISSN:0003-276X    

DOI:10.1002/ar.1092010310

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn preceeding studies, we clarified the histology of the deep cortex of the rat lymph node. It was shown that the deep cortex is made up of basic elements termed “deep cortex units,” some of which are fused to one another into “deep cortex complexes.” Each unit is a semirounded lymphocytic structure, centered on the opening of an afferent lymphatic, contiguous to the peripheral cortex, and bulging into the medulla of a node. Moreover, each unit comprises a “center” and a “periphery,” bearing distinct morphological features. The present work was undertaken to verify whether the histology of the deep cortex of nodes from various species of mammals, currently used for experimental immunology, is comparable to that of the rate. The observations yielded a positive answer

ISSN:0003-276X    

DOI:10.1002/ar.1092010311

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

年代:1981

数据来源: WILEY