摘要:

AbstractThe Fink‐Heimer silver impregnation and the autoradiographic methods were used to study the fiber projections of the cingulate cortex in the squirrel monkey. It was found that this cortex provides inputs to the striatum, thalamus and several areas of isocortex. Evidence was found for a number of fiber projections (1) Fibers from the anterior limbic area were traced to the central part of the head of the caudate nucleus, putamen, septum, dorsomedial nucleus of the thalamus, anterior hypothalamus and lateral basal nucleus of the amygdala. (2) Projections from the cingulate area were traced to the lateral part of the head of the caudate nucleus, putamen, and to the centromedian, anterior, lateral dorsal, and lateral ventral thalamic nuclei and to medial nuclei of the base of the pons. (3) There were projections from the retrosplenial area of the anterior, lateral dorsal, dorsomedial, and posterior thalamic nuclei and lateral nuclei of the pons. These results indicate that most of the cingulate gyrus is an intermediate structure between the thalamus and overlying cortex. The anterior limbic area forms a bridge between the thalamus and other areas of the cingulate gyrus and the frontal cortex. (4) The retrosplenial area and the posterior part of the cingulate area bridge the adjacent visual sensory association cortex and pelvic areas of the sensory motor cortex, respectively. These areas of the cingulate gyrus project directly to the striatum as well as to the thalamus, structurally providing limbic system input to subcortical motor structure

ISSN:0003-276X    

DOI:10.1002/ar.1091900402

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe gross morphology of the vas deferens of the rat and the changes that occur along its length are reported. It is shown that the organ can be divided into proximal, distal and terminal portions. Each portion is histologically unique and is situated in a different part of the body. The differences are discussed in relation to the function of the organ and their possible role in the consequences of vasectomy.

ISSN:0003-276X    

DOI:10.1002/ar.1091900403

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

年代:1978

数据来源: WILEY

摘要:

AbstractHeavy meromyosin (HMM) labeling was used to identify the nature of the filaments which form bundles in the cytoplasm of the pericytes in brain tissue. Rat brain tissue pieces were incubated in glycerol solutions at 4°, and then transferred into buffer (pH 7.0), (1) without HMM, (2) with HMM, (3) with HMM + 5 mM ATP, and (4) with HMM + 2.5 mM Na+pyrophosphate. In pericytes from untreated tissue, smooth‐surfaced microfilaments, averaging 6 nm in diameter, appear to branch and anastomose and to anchor on the plasma membrane. After exposure to HMM, the number and the density of the microfilaments are strikingly increased. These tightly‐packed microfilaments are now heavily coated with exogenous HMM thus increasing in width to 18–20 mm. They intertwine in closely‐woven networks. After incubation in HMM solutions containing ATP or Na+prophosphate, they are no longer coated with thick sidearms. It can thus be concluded that these microfilaments are of actin‐like nature. In addition, after incubation in ATP, they are intermingled with, and converge onto the surfaces of, thick, tapered filaments, which we have tentatively identified as of myosin‐like nature. Thus, it appears that certain of the major elements necessary for contraction are present in bra

ISSN:0003-276X    

DOI:10.1002/ar.1091900404

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

年代:1978

数据来源: WILEY

摘要:

AbstractNotochordal extracellular matrix consists of a continuous basal lamina, amorphous materials and microfibrils embedded in a ground substance of low electron density. Together they comprise the notochord sheath and are of considerable interest because of their suspected role in early embryonic tissue interactions. The notochord is particularly well‐suited to morphological investigation of extracellular matrix because it is one of the few embryonic epithelia which produces ultrastructurally recognizable stroma in vitro without the advantage of a collagenous substratum. Furthermore, these matrix components produced in vitro are morphologically identical to those observed in vivo. The present study uses ruthenium red staining to demonstrate that notochordal microfibrils exhibit collagen‐like cross‐banding patterns both in vivo and in vitro. Collagenase and testicular hyaluronidase digestion studies designed to localize collagen and glycosaminoglycans show a reduction of microfibrillar diameters by 30‐35%. Furthermore, these enzyme treatments frequently result in enhanced striations of microfibrils. When cis‐hydroxyproline (a proline analog) or beta‐aminoproprionitrile (BAPN, a lathyrogenic compound) is added to the culture medium, a similar reduction in microfibrillar diameters is seen. Moreover, increased ruthenium red‐positive surface coats and large collagen fibrils are frequently present in BAPN‐treated cultures, implying a stimulatory metabolic effect.We conclude that most, if not all, notochordal extracellular matrix components are composed of both collagen and glycosaminoglycans and suggest that the entire extracellular matrix should be considered a macromolecular composite which acts in concert to induce or stabilize development

ISSN:0003-276X    

DOI:10.1002/ar.1091900405

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe innervation of the rat cornea was investigated electron microscopically after KMnO4fixation. Myelinated nerve fibres were observed only in the limbal margin of the cornea, whereas the axons located in the stroma of the avascular cornea were surrounded by the Schwann cell cytoplasm. Axon profiles with small (300‐500 A) granular vesicles and another type with agranular vesicles were seen among the non‐vesiculated fibres in all parts of the cornea. After superior cervical ganglionectomy it was not possible to find any axons with small granular vesicles. On the other hand, some degenerating axon profiles were observed in the stromal nerve trunks after ganglionectomy. In the epithelium‐naked axons with an occasional mitochondrion and a few agranular vesicles penetrated between the epithelial cells. Moreover, axons filled with several mito‐chondria were rarely observed in the epithelium, but these were difficult to differentiate from the surrounding epithelial cells.The role of the different nerve types observed in the cornea is discussed. The results suggest that the rat cornea has a dual vegetative inne

ISSN:0003-276X    

DOI:10.1002/ar.1091900406

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe freeze‐fracture appearance of fenestrations of sinusoidal endothelial cells has been reassessed in perfusion‐fixed rat liver. Fenestrations, limited to the attenuated portions of the endothelial cell cytoplasm are usually round or oval in shape, with diameters ranging from 40‐600 nm. Within a given fenestrated region, they are disposed in clusters forming sieve plates. In addition, the presence of wide, irregularly shaped openings suggest that adjacent fenestrations may coalesce and result in the larger openings. Our data thus confirm the existence of both small and large fenestrae in the endothelial wall, in contradistinction to previous studies showing only regular, medium‐sized (100 nm) o

ISSN:0003-276X    

DOI:10.1002/ar.1091900407

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

年代:1978

数据来源: WILEY

摘要:

AbstractCilia in neonatal canine articular chondrocytes were studied using morphometric techniques and transmission electron microscopy. The cilia in chondrocytes were morphologically similar to cilia in a variety of other cell types. A chondrocytic cilium consisted of a basal body and a ciliary shaft. The cylindrical basal body was 0.21 μm (S.D. = 0.01 μm) in diameter, 0.50 μm (S.D. = 0.03 μm) in length and contained nine microtubular triplets. The ciliary shaft was 0.196 μm (S.D. = 0.02 μm) in diameter and 1.76 μm (S.D. = 0.80 μm) in length. The number of microtubular doublets in the ciliary shaft varied depending on where along the length of the shaft the section was taken.This study demonstrates that on the average the frequency of cilia in neonatal articular chondrocytes, as estimated stereologically, was about one cilium p

ISSN:0003-276X    

DOI:10.1002/ar.1091900408

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

年代:1978

数据来源: WILEY

摘要:

AbstractIn mature rat soleus muscle it is shown that satellite cells are not evenly distributed over the surface of myofibers but are more numerous in the vicinity of the motor endplate. In this location they commonly lie close to the post synaptic membrane where they are termed perisynaptic satellite cells. In developing muscle several satellite cells may be seen close to the endplate and give the impression of limiting the spread of the axon over the myofiber. In addition these satellite cells make close plasmalemmal contact with Schwann cells and appear as a continuation of the Schwann sheath onto the surface of the myofiber.

ISSN:0003-276X    

DOI:10.1002/ar.1091900409

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe phenomena of spermatogonial degeneration have been studied in normal adult rat testes using a simplified classification of the germinal epi‐thelium based upon the six types of differentiating spermatogonia. The following features distinguished this from schemes based on acrosome development. Rather than 14 stages of unequal duration, there are only six stages, five of which are of the same length. The classification starts at the beginning of spermatogenesis with A1spermatogonia rather than at the onset of spermiogenesis. The classification is derived from actual biological events in spermatogenesis, namely generation times of spermatogonia, rather than upon arbitrary events in acrosome development. Most importantly, this new classification can be used with most types of preparations and in most experimental conditions.Examination of tubular whole mounts reveals that degeneration preferentially occurs in types A2and A3and to a lesser extent A4spermatogonia, and is rarely seen in generations of A1In or B cells. Deterioration is first manifested in clusters of cells joined by the intercellular bridges as they complete DNA synthesis and enter the G2phase of cell cycle. It is characterized by a denser staining of the nuclear membrane, coalescence of chromatin into several pyknotic bodies, and eventual extrusion of the nuclear mass, leaving a cytoplasmic ghost. The sequential steps in degeneration may often be traced from one end of a synctial chain to the other, suggesting that the process may start with just one cell and then spread via intercellular bridges to involve all spermatogonia within the clone. Quantitatively, degeneration is a relatively constant feature of spermatogonial development. Only 25% of the theoretically possible number of pre‐leptotene spermatocytes are produced from the original population of A1spermatogonia; most of this loss is incurred during the maturation of A2and A3generations. While the reason for spermatogonial degeneration in the normal germinal epithe‐lium remain obscure, it is proposed that the numerical ratio of A spermatogonia to Sertoli cells may be a significant limiting f

ISSN:0003-276X    

DOI:10.1002/ar.1091900410

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

年代:1978

数据来源: WILEY

ISSN:0003-276X    

DOI:10.1002/ar.1091900401

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

年代:1978

数据来源: WILEY