摘要:

AbstractTritiated digitonin of high specific activity has been incorporated into fixation of adult rat sciatic nerve. Electron microscope autoradiograms developed four to thirteen days after coating indicate highest concentration of label over or near myelin sheaths. Label is observed over areas of reasonable myelin preservation as well as in areas of artifact and membrane disruption. The technique is suggested for use as a means of fairly specific localization of free cholesterol in tissues. In addition, the activity of the isotope used permits visualization of autoradiograms after short exposure times.

ISSN:0003-276X    

DOI:10.1002/ar.1091740202

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe eosinophil granules of the dog have a dense matrix with or without a light peripheral rim. Lamellated crystalloids are demonstrated in their dense matrix. The lamellation consists of alternating dark and light bands resembling crystalloids of other species. The center to center distance between the consecutive dark bands measures approximately 107 Å. The crystalloids appear to take rather variable forms ranging from large, triangular to small, elongated or irregular shape

ISSN:0003-276X    

DOI:10.1002/ar.1091740203

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

年代:1972

数据来源: WILEY

摘要:

AbstractDeciduous tooth germs were removed from the anterior region of human fetuses between 13‐16 weeks of age and fixed in glutaraldehyde. Some were post fixed in osmium tetroxide whilst others were block stained with silver nitrate and prepared for electron microscopy. Thick Araldite embedded sections were cut at 1 μm and stained in various ways for examination by light microscopy. Thin sections of bulk silver stained material were examined with the electron microscope before and after staining with heavy metals.Fibers lying between the developing odontoblasts were demonstrable under the light microscope and their appearance was consistent with the classical description of von Korff fibers. With the electron microscope bundles of collagen fibers up to 1 μm in diameter were present between newly differentiated odontoblasts. Heavy metal staining of sections from bulk silver impregnated material revealed that silver deposition was associated mainly with collagen fibrils. It is concluded that in the crown of human developing teeth, bundles of collagen fibrils are present between the newly differentiated odontoblasts and that these bundles represent those usually described as von Korff fibers.Similar results were found using material from developing molar teeth of m

ISSN:0003-276X    

DOI:10.1002/ar.1091740204

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe effect of stress‐induced release of ACTH or suppression of ACTH release on concentric whorls of rough endoplasmic reticulum has been studied in the adrenal gland of the Mongolian gerbil. The border zone between the zona fasciculata and reticularis appears to be a zone of transition, and stress may transform these cells into typical zona fasciculata cells. Absence (hypophysectomy) or reduction (testosterone, dexamethasone) of ACTH however causes neither atrophy nor hypertrophy of whorls. The stress of saline injections for five days caused disappearance of whorls and a rise in blood cortisol to 1.5 times that in controls. Whorls were replaced by a focal accumulation of smooth endoplasmic reticulum. Testosterone or dexamethasone as well as transaural hypophysectomy prevented the disappearance of whorls in spite of the stress of injection. Testosterone caused a 50% reduction in blood cortisol levels whereas both dexamethasone and hypophysectomy reduced blood cortisol to 25% of that in control

ISSN:0003-276X    

DOI:10.1002/ar.1091740205

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe ultrastructure of cell surface and tissue organization of reproductive tracts of female rabbits were observed by scanning electron microscopy. In the vagina, straight and shallow longitudinal folds were observed. Complex, very deep, narrow folds with small crypts were observed in the cervix uteri. Two types of cells were recognized: ciliated cells and secretory non‐ciliated cells. The internal os area contained more ciliated cells than the external os area. In the uterus, two different patterns of fold formations were observed: shallow fold formation in a random direction or mosaic pattern in the lower part of the uterus, and wave‐like folds in the middle or upper part of the uterus. The lower part of the uterus contained more ciliated cells than the mid and upper part of the uterus. At the uterotubal junction, four large folds and four small folds from the isthmus are projected into the uterine lumen forming a rosette‐like structure. In the oviduct, longitudinal fold formations were observed through the isthmus to ampullae. The number of ciliated cells gradually increased from the isthmus to the ampullae. The fimbriae, made of several mucosal folds arranged like flower petals, were composed of a high percentage of ciliated

ISSN:0003-276X    

DOI:10.1002/ar.1091740206

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

年代:1972

数据来源: WILEY

摘要:

AbstractMast cells were detected in the brains of kangaroo rats, gerbils and albino rats. They were most numerous in diencephalic structures (leptomeninges, choroid plexuses, nuclei, tracts); moderately abundant in telencephalic and mesencephalic structures (leptomeninges, choroid plexuses, nuclei, tracts); and least plentiful in metencephalic and myelencephalic structures. They were not detected in the spinal cord. In all cases the mast cells were closely associated with the blood vessels in these regions.

ISSN:0003-276X    

DOI:10.1002/ar.1091740207

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

年代:1972

数据来源: WILEY

摘要:

AbstractLocalization of acid phosphatase in trigeminal ganglia of vascularly perfused, young, Wistar rats was demonstrated by Gomori's lead sulfide and Barka and Anderson's azo dye methods. Differences in deposition of reaction product, indicating differences in levels of enzyme activity, were demonstrated between small, intensely reactive (dark) neurons and larger, less reactive (light) neurons. Lengthening the fixation time to lessen the likelihood of artifactual origin of such differences resulted in a decreased reaction in all neurons; relative difference in intensity of large and small neurons was retained. The results indicate that the level of detectable acid phosphatase activity is an additional distinguishing feature between light and dark cells in trigeminal ganglia of the rat and suggest that differences between these cells are not artifactual.

ISSN:0003-276X    

DOI:10.1002/ar.1091740208

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

年代:1972

数据来源: WILEY

摘要:

AbstractDegeneration of unknown etiology was noted in the spinal nerve roots of aging rats. These animals (Charles River CD® rats) were included in a study of long‐term effects of ionizing radiation. The initial lesion was a de‐myelination of an individual axon or a few, isolated, scattered axons in the ventral roots of rats between 18 and 20 months of age. As the lesion progressed, the dorsal roots showed involvement, and by 24 months the usual finding was marked degeneration in ventral roots with degenerative changes of a lesser degree in the dorsal roots. When degeneration was complete, connective tissue filled the regions normally occupied by neural tissue. The lesion was unrelated to the radiation procedure, occurring with equal frequency in both irradiated and non‐irradiated animals. Furthermore, lesions occurred with equal frequency in both males and females. The one factor to which the lesion appeared to be related was age since it was not observed in animals less than 18 months old but was seen in 66.7% of those between 18 and 20 months and in 96.0% of those older than 20 months. These data indicate that this lesion needs to be considered when using aging laborator

ISSN:0003-276X    

DOI:10.1002/ar.1091740209

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe total Leydig cell volume has been determined in 40 dog testes using a histometric point‐counting method. In preliminary experiments, the accuracy of the method has been established on specially prepared plasticine models of the testis. The point‐counting method has a mean error of ± 7% and the values obtained by it, when statistically analysed, are not significantly different from those determined by direct measurements (p>10% ). Thus, work on the models has provided convincing experimental verification of the method.The Leydig cells constitute about 15% (14.2 to 17.1% ) of the testicular volume in dogs. In absolute terms, it comes out to be 1.56 ± 0.45 ml of Leydig cells per testis. Larger testes contain proportionally greater amount of Leydig cell tissue, the relationship being almost linear. Although very little data is available for comparison, and none perhaps for the dog, it appears from the present study that the total quantity of Leydig cells in this species is essentially the same as in man.Since it allows a reliable estimate of the total Leydig cell volume directly in milliliters per testis, the point‐counting method has proved to be much more useful than older methods which merely determined the proportion of Leydig cells in relation to some other testicular co

ISSN:0003-276X    

DOI:10.1002/ar.1091740210

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

年代:1972

数据来源: WILEY

摘要:

AbstractThe present study was undertaken to determine what structural changes hypophysectomy would cause in the rat kidney. Proximal convoluted tubule cells from hypophysectomized rats were smaller and their length was decreased when compared to kidneys from control animals of approximately the same weight as the hypophysectomized animals. Electron microscopic observation of the kidneys from the hypophysectomized rats revealed that the cells of the proximal convoluted tubules had (1) an increase in size and number of dense bodies (type II cytosome); (2) a decrease in smooth endoplasmic reticulum (SER); (3) a decrease in basilar infoldings; (4) an increase in the frequency of mitochondria cristae aligned in their longitudinal axis and (5) a change in the character of the profiles of smooth endoplasmic reticulum (SER) related to microbodies (type I cytosome) from a vesicular to tubular arrangement. The changes noted in the cells of the proximal convoluted tubules of hypophysectomized rats were similar to previously described changes observed in tubular atrophy.

ISSN:0003-276X    

DOI:10.1002/ar.1091740211

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

年代:1972

数据来源: WILEY