摘要:

AbstractMice were given a single injection of cortisone acetate and killed from one to seven days later. Arterial lesions occurred first and were predominantly located in the right ventricle. Hyalin was present in media of these coronary arteries within 24 hours following administration of cortisone. Exudative and proliferative changes in the arterial walls and perivascular spaces followed medial hyalinization. The highest incidence of arterial lesions (90%) was attained on the third day following cortisone injection and then decreased slightly (57%) by the seventh day. Myocardial necrosis was observed first in mice killed 48 hours after receiving cortisone and the incidence did not change significantly thereafter.

ISSN:0003-276X    

DOI:10.1002/ar.1091600102

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe testes, seminal vesicles and coagulating glands of hamsters subjected to bilateral optic enucleation (blinding) involuted within 6–8 weeks. During the first several weeks after blinding there was relatively little change in the weights of the reproductive organs, however, between 4–6 weeks the weights of these organs declined precipitously. Finally, the testes and accessory sex organs of 8‐week blinded hamsters were about one‐tenth and one‐third their normal size, respectively. The atrophic testes exhibited a complete loss of spermatogensis and an apparent diminished secretion of androgens since the seminal vesicles and coagulating glands also regressed significantly. Despite the involution, the testes showed a high degree of deoxyribonucleic acid synthesis as evidenced by the large number of spermatogenic cells which took up tritiated thymidine. These findings indicate that the testes retained a certain level of regenerative capacity even in the presence of advanced tubular damage.If hamsters blinded for 9 weeks, had either their pineal gland or superior cervical ganglia removed, the involuted testes and accessory organs regenerated and returned to the normal size, and presumed function, within approximately 8 weeks. Regenerated testes were histologically indistinguishable from those of normal animals. Eyeless hamsters killed after 17 weeks still possessed involuted reproducti

ISSN:0003-276X    

DOI:10.1002/ar.1091600103

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

年代:1968

数据来源: WILEY

摘要:

AbstractA series of experiments utilizing the technique of Rostgaard and Barrnett which purported to demonstrate lead‐lipid complexes was performed to study the efficacy of using lead as a marker in lipid absorption.The jejunal mucosa from adult cats fasted 48 hours and fed corn oil by stomach tube was fixed in buffered glutaraldehyde for two hours, washed in cacodylate buffer and then incubated for 20 minutes in tris‐maleate buffer (pH 7.2) which contained 4mM of lead nitrate. Following osmication, dehydration and embedding in Epon, thin sections, either stained or unstained were examined in an electron microscope. Lead deposits of varying size were observed in, on and about the microvilli. In addition, lead deposits were observed related to mucous cells. The jejunal mucosa of cats fasted 48 hours and fed 5% dextrose and treated as the lipid‐fed animals gave similar results. Fasted animals had few lead deposits related to the gut epithelium.When jejunal mucosa from lipid‐ or carbohydrate‐fed animals was extracted in lipid solvents prior to incubation in tris‐maleate containing 4mM of lead nitrate, the lead densities persisted.In view of the foregoing, the occurrence of lead precipitates following a fatty meal does not offer an unequivocal means of tracing lipid absorption in the smal

ISSN:0003-276X    

DOI:10.1002/ar.1091600104

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

年代:1968

数据来源: WILEY

摘要:

AbstractRats were ovariectomized on the eighth day of pregnancy and either 10 or 20 mg of progesterone, 10 mg of progesterone with 1 μg estradiol benzoate or 1 μg estradiol benzoate alone were administered between the eighth and twelfth day. On the twelfth day tritiated thymidine was injected to study mitoses in the junctional zone cells of the placenta by autoradiography, and tracings of spontaneous uterine contractions were made. Twenty milligrams of progesterone daily sustained pregnancy to the twelfth day in spayed rats as effectively as it was sustained in the untreated normal rats; 10 mg progesterone daily was less effective and 10 mg progesterone with 1 μg estradiol benzoate did not maintain normal pregnancy. Progesterone produced normal rates of mitosis in the placental trophoblast cells of spayed rats. No correlation was found between the maintenance of pregnancy and decreased contractions of the myometrium in this study. The injection of 20 mg progesterone produced patterns of contraction similar to the normal contraction patterns and differing from those found in spayed rats and in rats injected with 10 mg progesterone, progesterone and estradiol benzoate or estradiol benzoate alone. It is concluded that a sufficient supply of progesterone maintains both normal mitotic activity in the trophoblastic cells and normal patterns of contraction by the muscle of the uter

ISSN:0003-276X    

DOI:10.1002/ar.1091600105

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

年代:1968

数据来源: WILEY

摘要:

AbstractWhen lymphoid cells from the thoracic duct lymph, blood, lymph node, spleen and thymus of the rat were exposed to pokeweed mitogen (PWM), large primitive cells appeared after 24–30 hours of culture. This response was not limited to tissues of adult animals but was also demonstrated in cultures of cells from the thymus glands, lymph nodes and spleens of newborn, 48 hour and three‐day‐old rats, respectively. The transformed rat cells, in contrast to the cells observed in human PWM cultures (Chessin, Bőrjeson, Welch, Douglas and Cooper, '67), could not be divided into two populations on the basis of cytoplasmic basophilia, PAS positive granules or alcian blue staining. In addition, the thoracic duct lymphocytes from rats thymectomized within 24 hours of birth showed a marked deficiency in transformation, characterized by decreased numbers of enlarged cells and minimal cytoplasmic basophilia, when compared to similar cells from non‐operated or sham‐thymectomized controls.In the thymus cultures, some of the small lymphocytes served as precursors of the transformed cells without undergoing division. Subsequently, these enlarged cells proliferated giving rise to small lymphocytes and additional transformed elements. Exposing lymphoid cells to PWM for up to 14 days did not result in the development of pl

ISSN:0003-276X    

DOI:10.1002/ar.1091600106

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

年代:1968

数据来源: WILEY

摘要:

AbstractSections of the human hypophysis were fixed in either formalin or Bouin's fluid and stained by a variety of mucoid and acid stains in order to demonstrate the staining characteristics of the mucoid cells of thepars distalis.Five types of mucoid cells were revealed and designated as cell types III, IV, V, VI and IX according to the classification system of Ezrin. Cell types III, IV, V and VI were present throughout thepars distaliswhile cell type IX was observed only in the posterior zone.The cells were tinctorially distinguished by the PAS‐orange G affinity of the type III cell, the alcian blue‐PAS reactivity of the type IV cell, the alcian blue staining of the type V cell and the affinity of the type VI cell for alcian blue‐PAS‐orange G. Cell type IX was recognized by the affinity of its cytoplasmic granules for most of the stains employed. Modified and degranulated forms of these cells were observed and are also de

ISSN:0003-276X    

DOI:10.1002/ar.1091600107

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

年代:1968

数据来源: WILEY

摘要:

AbstractUnderstanding the development of the human adenohypophysis is dependent on visualizing the growth of Rathke's pouch. This embryonic structure gives rise to bilateral anterior and posterior, superior and inferior segments. These segments differ in their potential to produce various types of hypophyseal chromophils. The potential differences are described in the text.Further, by application of specific staining procedures it has been possible to determine the approximate time that specific chromophils appear in the adenohypophysis. The chromophils of the adenohypophysis develop in the order: cell type III, I, IV, II, V, VI and IX. There may be a relationship between the development of certain chromophils and the onset of function in target endocrine glands.

ISSN:0003-276X    

DOI:10.1002/ar.1091600108

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

年代:1968

数据来源: WILEY

摘要:

AbstractAn electron microscopic study of extracellular connective tissue fibrils in the chick embryo is reported herein. Primary fibrils (40–45 Å) are first to appear, being present in the primordia of ectodermal boundary (basement) membranes in freshly laid eggs. Free microfibrils (40–150 Å) appear by delamination from boundary membranes from 24 hours incubation onward. The notochord becomes intensely active in forming microfibrils toward the end of the second day. By 72 hours free mesenchymal cells are producing microfibrils. Axial periodicity is acquired relatively slowly by microfibrils in their transition to unit collagen fibrils. At one week's incubation fibrillar diameters and periodic banding still do not match the recognized adult pattern.The hypothesis that a single developmental line of fibrils leads to all extracellular connective tissue fibrous elements is supported by the ontogeny of fine structure in the chick. Microfibrils first arise in close association with primary fibrils, then from notochordal cells and later, more directly from free mesodermal cells (mesenchyme, fibroblasts). The collagen, reticular and elastic fibers of light microscopy arise from aggregations and alterations of fibrillar material whose line of descent is traceable to the microf

ISSN:0003-276X    

DOI:10.1002/ar.1091600109

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

年代:1968

数据来源: WILEY

摘要:

AbstractMicrotubules, 210–230 Å in diameter and many microns in length, with an associated “clear zone” around them, 450–550 Å in diameter, are demonstrated in large numbers in cells of theStratum Granulosumof newborn rat epidermis. Few microtubules are found in the uppermost portion of theStratum Granulosumnor are they found above this layer in theStratum Corneum. Few microtubules are found in the germinal cells of the epidermis. Upon entering theStratum Granulosum, cells undergo shape changes involving elongation and flattening. Microtubules have elsewhere been implicated in whole cell movement and in the movement of portions of cytoplasm, including specifically cell elongation and the related functions of maintenance of asymmetric cell shapes and projections. Evidence is presented here in support of the hypothesis that microtubules are the basic cytoplasmic structure responsible for this motility. Two cortical arrays of microtubules, parallel and orthogonal in orientation, are demonstrated at different stages of cell flattening in epidermis. If the mode of action of microtubules is undulation and resulting “intracytoplasmic peristalis,” these orthogonal arrays represent a mechanism for the formation of the shape of squamous cells. The similar orientations of microtubule populations in many cells would seem to indicate that microtubule undulation and the resulting interaction between neighboring cells accounts for the transmission of axes of orientation

ISSN:0003-276X    

DOI:10.1002/ar.1091600110

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

年代:1968

数据来源: WILEY

摘要:

AbstractThe left ventricular papillary muscles of rats were studied under the electron microscope. The tissue was fixed in glutaraldehyde 6.25%, postfixed in osmium tetroxide 2% and embedded in Epon 812. Sections were stained with lead according to Karnovsky.The terminal distribution of nerve fibers and their relationship with target cells represented by cardiac and vascular smooth muscles were investigated. Nerve bundles followed the course of vessels to the perivascular spaces around the smallest arterioles. At this level the bundles became progressively thinner and individual axons were observed leaving the bundles and penetrating between myocardial cells. In the micrographs, the unmedullated axons contained in the bundles were of three different types. Axons of type 1, chiefly containing neurofilaments, were considered the most proximal portion of the nerve fibers involved in the conduction of impulses. Axons of type 2 were characterized by the appearance of agranular and granular vesicles. Axons of type 3, or nerve endings, represented the anatomical endpoint of individual axons. True myoneural junctions (nerve‐muscle close contact) have been detected. More frequently, axons of type 3 end in the intercellular space (loose contact). Only a loose contact relationship was observed between the axons and vessels wall

ISSN:0003-276X    

DOI:10.1002/ar.1091600111

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

年代:1968

数据来源: WILEY