摘要:

AbstractThe ultrastructure of the tubuli recti was studied in the testes of sexually mature bulls, boars, rams, goats, rabbits and rats fixed by vascular perfusion. The tubuli recti are lined with a simple epithelium that varies in height, from squamous to tall columnar according to the species and the region. The cells are characterized by extensive lateral and tortuous basal plasma membranes and a luminal border with microvilli. Tight junctions and desmosomes are found in the upper half of the lateral borders. The Golgi apparatus is sizable and associated with it are coated vesicles and may smooth vesicles concentrated towards the luminal border. A distal segment of the tubuli recti is found in bulls only and is characterized by a high epithelium which is thrown into folds giving the lumen a festooned appearance. It is suggested that the epithelial cells of the tubuli recti are involved in fluid exchange and in the removal of unwanted spermatozoa.

ISSN:0003-276X    

DOI:10.1002/ar.1091920102

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

年代:1978

数据来源: WILEY

摘要:

AbstractA light and transmission electron microscopic study was performed on 67 ductus arteriosus (DA) specimens from rabbits (31 days normal gestation period) ranging in age from 21 days of gestation to 4 days after birth. Some fetuses were permitted to breath before sampling, while others were not. The aorta and pulmonary trunk served as controls. The objectives of the study were to identify the earliest cellular alterations leading to closure of the DA, to study in detail the sequence of cellular changes in closure of the DA, and to correlate these observations with what is known about the physiological factors involved in closure of the DA. Changes in the architecture of the DA wall were seen as early as on the twenty‐sixth day of gestation and involved the appearance of increased numbers of radially or longitudinally reoriented smooth muscle cells in the intima and fragmentation of the internal elastic lamina. The progress of these changes continued and intensified until the end of gestation. At that stage the inner one‐half of the medial smooth muscle cells was reoriented, and the lumen was significantly reduced by a greatly expanded intima which often contained many intercellular “ghost bodies.” Very few mitoses were seen during DA closure, especially during 29 to 31 days of gestation. It is concluded that cellular changes involved in closure of the DA of the rabbit fetus begin far in advance of birth and breathing. These cellular changes are highly analogous to those which occur in the early pathogenesis of arterial intimal fibromuscular lesions. Closure of the DA, therefore, seems to afford an excellent, natural model for study of key cellular events involved in the production of arterial fibromuscular

ISSN:0003-276X    

DOI:10.1002/ar.1091920103

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

年代:1978

数据来源: WILEY

摘要:

AbstractStudies were undertaken to assess the fine structural effects of vasectomy upon the rhesus monkey testis, using 27 monkeys subjected to one of three surgical techniques: control sham operation (COS), unilateral silk vasoligation (USV), or unilateral clasp vaso‐occlusion (UCV). The monkeys were sacrificed from 1 to 66 weeks after surgery; tissues were fixed in glutaral‐dehyde in collidine buffer and processed for electron microscopy (EM) using routine techniques. No alterations were noted in the seminiferous epithelium of any COS animal; only focal lesions were found in vasectomized animals. These changes correlated with length of time post‐vasectomy, a finding consistent with earlier light microscopic studies (Heidger et al., '78). Even at the longest post‐operative periods studied, spermatogenesis appeared in most animals to be normal. One animal exhibited areas in which the seminiferous epithelium consisted of Sertoli cells and spermatogonia, only. The seminiferous epithelium of approximately one‐third of other animals, both on the vasectomized and contra‐lateral sides, exhibited such alterations as development of extensive infoldings and duplication within the basal lamina, and presence within the basal Sertoli cell cytoplasm of late spermatids and sperm tails. These alterations were observed in both UCV and USV animals. The presence of such late germ cells in the basal Sertoli cell cytoplasm was noted by light microscopy; however, lu‐minal spermiophages encountered in one animal at the light microscopic level were not detected in our EM study, which underscores the limitations of EM as a survey technique. All UCV animals developed spermatic granulomas of the vas, whereas only 3 of 13 USV animals developed such granulomas. It does not appear that the alterations exhibited by the animals in this study would necessarily dispose toward impaired spermatogenesis following

ISSN:0003-276X    

DOI:10.1002/ar.1091920104

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

年代:1978

数据来源: WILEY

摘要:

AbstractTenotomy of the proximal and distal tendons of the soleus muscle of female Wistar rats was performed and sarcomeric length and muscle fascicle length measured. On the first postoperative day muscle bellies were found shortened and their sarcomeric length considerably reduced. Four weeks following tenotomy, although the muscle bellies remained shortened, sar‐comeric length was comparable with that of control muscles. Measurement of muscle fascicle lengths at this time showed that those of experimental muscles were nearly 50% less than those of control muscles. It was concluded from these experiments that a reduction of the number of sarcomeres in series had occurred, thus compensating for the reduced length of the muscle bell

ISSN:0003-276X    

DOI:10.1002/ar.1091920105

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe majority of human cardiac glands that lie immediately distal to the termination of esophageal epithelium are compound or branched tubular glands. They empty into overlying gastric pits. The glands of this region are often organized into lobule‐like complexes by the surrounding connective tissue of the lamina propria. The secretory tubules contain mucous cells, parie‐tal cells and endocrine cells. The mucous cell is the most common cell type observed and appears to comprise two populations. The majority are pyramidal in shape and show numerous spherical, electron‐dense secretory granules. Profiles of rough endoplasmic reticulum are observed scattered throughout the cytoplasm and Golgi complexes occupy a supranuclear position in relation to forming secretory granules. Morphologically this cell type appears similar to the mucous neck cell of the fundus. Secretory granules of a second mucous cell type are mottled in appearance and show an area of increased electron density near the limiting membrane. Parietal cells are observed and appear identical to those in the fundus. The large number of endocrine cells present raises questions concerning the traditional concept of the function of these particular g

ISSN:0003-276X    

DOI:10.1002/ar.1091920106

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

年代:1978

数据来源: WILEY

摘要:

AbstractThe objective of this study was to determine the effects of chronic dexamethasone (DEX) administration on hepatic ultrastructure and to correlate these changes with plasma lipoprotein levels. Electron microscopic studies were made of hepatocytes from male rats killed 1, 3 and 5 days after DEX (2 mg, twice per day) administration. Three days after treatment plasma lipoprotein levels were highest and hepatocytes contained regions of the cytosome rich in elements of the smooth endoplasmic reticulum (SER). Osmiophilic particles were present in the tubules and vesicles of the SER, in the saccules and vacuoles of the Golgi complex, in secretory vesicles near the cell surface and in the space of Disse. DEX treatments also caused hepatocytes to accumulate tightly packed masses of β‐particles of glycogen in some regions of the cell while other areas displayed dispersed glycogen particles that were associated with the SER. These observations are consistent with the hypothesis that glucocorticoids 1. cause an elevation of plasma lipoprotein levels by in creasing hepatic synthesis and secretion of VLDL, which involves the sequential participation of the ER, the Golgi complex and exocytosis of VLDL‐containing vacuoles into the space of Disse, and 2. produce a change in the nature of the association of glycogen particles with the SER membranes in response to the physiological state of the an

ISSN:0003-276X    

DOI:10.1002/ar.1091920107

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.1091920108

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.1091920101

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

年代:1978

数据来源: WILEY