摘要:

AbstractDesmosomes and hemidesmosomes from larval newt epidermis were examined by freeze‐fracture methods incorporating low osmolality fixation, short duration glycerination, complementary replica comparison, stereo imaging, and dark shadow printing. These procedures provide new evidence regarding the structure of “traversing” filaments as mediators of attachment between intermediate filaments and the cell membranes of desmosomes and hemidesmosomes. A detailed analysis of intramembranous particles and other structure in these attachments has also been possible. The relationship of this evidence to models of desmosomal structure suggested by other authors is disc

ISSN:0003-276X    

DOI:10.1002/ar.1091990102

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe purpose of this study was to examine the distribution and mobility of anionic sites on the surface of fetal trophoblast in contact with maternal blood using polycationic ferritin (PCF) as a probe. Pieces of human placental villi were washed to remove maternal blood, and fresh, unfixed tissue was expose to PCF for varying times, concentrations, and temperatures to determine the effects on labeling patterns. The major findings were: (1) anionic sites were localized almost exclusively on the microvillous portion of the trophoblast surface; intermicrovillous regions of the surface, including the coated pits, were generally not labeled with PCF; (2) PCF binding was present as small clusters on the microvilli. This pattern was observed in tissue incubated 5–10 sec at 4°C and 23°C. The size of the cluster was increased with increased incubation time, suggesting some aggregation or patching can occur; (3) following the fomation of patches, the anionic sites showed no evidence of being cleared from the membrane by endocytosis during incubation subsequent to labeling; (4) the binding of PCF to the surface was reduced by pretreatment of the tissue with neuraminidase. Tissue fixed in glutaraldehyde prior to PCF exposure showed both clustered and more dispersed labeling. The results indicate that anionic sites on human trophoblast surface have a non‐random distribution and have restricted mobility on the surface. This may be indicative of a segregation of different membrane proteins and functions within different structural regions of the placental cell su

ISSN:0003-276X    

DOI:10.1002/ar.1091990103

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

年代:1981

数据来源: WILEY

摘要:

AbstractWe have investigated morphologic and histochemical characteristics of serotonin‐containing epithelial cells in tracheas from adult rabbits, using the Falck‐Hillarp freeze‐dried formaldehyde vapor technique. An intracellular formaldehyde‐induced fluorescent substance was identified as serotonin by microspectrofluorometric techniques. Fluorescence microscopy and subsequent histochemical staining of the same sections demonstrated that serotonin‐containing cells were argentaffin‐, argyrophil‐, and ferric ferricyanide‐positive. The serotonin‐containing epithelial cells were more numerous in ventral than in dorsal aspects of trachea. The number of detectable fluorescent cells was reduced after reserpine administration but was not affected by injecting the amine precursor L‐dihydroxyphenylalanine (L‐DOPA). The emission peak of the fluorophore was not significantly shifted after L‐DOPA injections. The cells may regulate tracheobronchial‐pulmonary function by releasing serotonin or other as yet unidentified biolo

ISSN:0003-276X    

DOI:10.1002/ar.1091990104

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

年代:1981

数据来源: WILEY

摘要:

AbstractShell‐less cultrure involves culturing chick embryos with associated yolk and albumen outside of the eggshell and shell membranes. The technique allows direct access to and continuous observation of cultured embryos almost to the time of hatching. The plastic wrap/culture tripod technique described in this paper allows normal embryonic growth and differentiation from 48 hours (in ovo pre‐incubation age) through at least 10 days of total incubation. As the duration of in ovo pre‐incubation is decreased below 36 hours, there is a concomitant increase in the percentage of grossly abnormal embryos associated with decreased survival and retarded growth and differentiation. Survival of embryos pre‐incubated for 72 hours through 13 and 18 days of total incubation is greater than 80% and 40%, respectively. The wrap/tripod technique allows substantially better survival and more normal development of cultured embryos than does the petri dish technique of Auerbach et al. (1974). Embryonic growth in 7.8‐cm‐diameter chambers is significantly greater than in either larger (10.6 cm) or smaller (5.2 cm) diameter chambers. Some gas exchange through the culture chamber walls appears necessary for optional embryonic survival and growth. Suspending egg contents in either Safeway® or Handi‐Wrap® plastic wrap (both of intermediate permeability) in 7.8‐cm tripods resulted in superior growth and/or survival compared to suspension in Silastic® sheeting (high permeability), Saran Wrap® (low permeability), glass dishes (nonpermeable), or glass dishes lined with an inner layer of Safeway

ISSN:0003-276X    

DOI:10.1002/ar.1091990105

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

年代:1981

数据来源: WILEY

摘要:

AbstractDiagrams of the lymph node currently represent its deep cortex (paracortex) as a layer of rather uniform thickness underlying the whole peripheral cortex. However, this concept has not been supported by actual observations; previous nvestigators have observed, instead, related structures whose appearance varied greatly from nodule‐like to ill‐defined components. Clearly, the present knowledge of the histology of the deep cortex is inadequate and confusing. Therefore, we undertook a tridimensional study of the region in different nodes of rats. The present work, bearing on the topography of the region, revealed that the deep cortex of the rat node is formed of one to several basic “units”. Each unit is a semi‐rounded structure, varying from semispheric to semi‐ovoid in shape and contiguous to a portion of peripheral cortex. The work further showed that two to several units can fuse to form a “complex”. The data indicated that the number, the size and the shape of the units and/or of the complexes of a node differ to some extent according to its anatomical location. These differences probably reflect corresponding variations in the nature and importance of the antigenic stimulation in the different sites of the organism. Finally, the study demonstrated the necessity of tridimensional examination of a node to obtain adequate information on its overall architecture and, particularly, on its deep co

ISSN:0003-276X    

DOI:10.1002/ar.1091990106

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

年代:1981

数据来源: WILEY

摘要:

AbstractRecently, we reported that the deep cortex of the rat lymph node is formed of semi‐rounded structures, the “deep cortex units,” contiguous to the peripheral cortex and bulging into the medulla. It was suggested that a unit represents an accumulation of lymphocytes centered on the opening of an afferent lymphatic vessel. To verify the proposal, we carried out a tridimensional analysis of serially sectioned rat nodes, fixed by perfusion and trimmed in such a way as to preserve their lymphatics. The tridimensional analysis revealed that a constant topographical relationship exists between the units and the openings of the afferent lymphatics. The results demonstrated that the topographical organization of the deep cortex of a rat node correlates with the distribution pattern of the opening(s) of its afferent lymphatic(s). The overall observations suggested the following explanation for the shape and topography of the units: factor(s) present in the lymph would spread in a radial manner from the opening(s) of an afferent lymphatic through the underlying cortex. The factor(s) would induce morphological modifications in the stimulated semi‐rounded area which, in turn, would provoke a local accumulation of circulating lymp

ISSN:0003-276X    

DOI:10.1002/ar.1091990107

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

年代:1981

数据来源: WILEY

摘要:

AbstractSeminal vesicles (SV) and coagulating glands (CG) from neonatal mice 1‐ to 7‐days old were observed in whole mount preparations. Untreated, normal SV developed elaborate epithelial branches beginning on day 3 with secondary branches appearing on day 6. Castration (C), estradiol treatment (E), and castration combined with estradiol treatment (C + E) inhibited the morphogenesis of the epithelial branches. Untreated CG formed solid epithelial stalks that developed lateral epithelial buds on day 3 which attained a complex morphological pattern by day 7. Treatment groups (C, E, and C + E) displayed a pattern of retarded growth with few epithelial buds appearing even at day 7. The effects of castration on both SV and CG were reversed by the addition of testosterone. Short term in vitro culture of 1‐day‐old SV and CG glands in control medium or medium supplemented with estradiol did not exhibit visible growth. Culture of SV and CG glands with testosterone or a piece of testis showed pronounced deve

ISSN:0003-276X    

DOI:10.1002/ar.1091990108

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe electron microscopic localization of insulin, glucagon, somatostatin, and pancreatic polypeptide (PP) in the pancreas of the iguanid lizard,Anolis carolinensiswas studied by the unlabeled antibody peroxidase‐antiperoxidase immunocytochemical technique. Insulin, glucagon, and somatostatin were localized absolutely to those cells previously identified on the basis of the characteristics of their secretory granules as being β cells, α cell, and D cells, respectively. The secretory granule cores of the PP‐containing cells appeared to be ellipsoidal with a semi‐major axis of 450 nm and a semi‐minor axis of 365 nm. This previously unidentified cell type is named the F cell, in keeping with the localization of PP to the original F cell of the canine pancreas. Without immunocytochemical staining, the qualitative ultrastructural characteristics of the F cell secretory granules were inadequate to permit certain identification of the F cell, especially with regard to t

ISSN:0003-276X    

DOI:10.1002/ar.1091990109

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe length, diameter, and angle of branching of all airways through the sixth level of branching below the trachea were measured on corrosion casts prepared from the lungs of two animals whose bronchial geometry has not previously been studied, namely the donkey and the rabbit. These measurements and morphometric data for the rat, hamster, dog, and human obtained from other sources were analyzed and compared. The cast prepared from human lungs exhibited an airway geometry that was clearly distinct from that shown by the nonhuman species. The human upper bronchial tree was the most symmetrical with respect to airway diameter and angle of branching. In all species studied, airway length was the most irregular parameter. The reasons for differences in branching geometry are not clearly understood. However, when attempting to determine whether a particular species may be used as a model for man in inhalation toxicology, and in the subsequent interpretation of animal data, an appreciation of differences in airway morphometry is essential.

ISSN:0003-276X    

DOI:10.1002/ar.1091990110

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

年代:1981

数据来源: WILEY

摘要:

AbstractProtein synthesis and secretion in mouse uterine glands during the peri‐implantation period were studied, by both light and electron microscopic autoradiography, after the in vivo administration of tritiated leucine (3H‐leucine) and proline (3H‐proline). Light microscopic autoradiography revealed that the time course of synthesis and secretion of labeled proteins was constant during days four, five, and six of pregnancy. Labeled material could be detected in the glandular lumen by 45 minutes after administration and in higher concentrations by 90 minutes after administration.Analysis of electron microscopic autoradiographs from days five and six of pregnancy showed that high levels of activity were initially present over the rough endoplasmic reticulum and Golgi complexes and subsequently declined at the longer time intervals (45 and 90 minutes), while activity over the glandular lumen increased with time. The pathway of intracellular transport to the glandular lumen appeared to be via small cytoplasmic vesicles on both days five and six of pregnancy. Additional pathways for transport of the labeled protein to the glandular lumen appeared to be present in the form of the large vesicles on day five and granules on day six of pregnancy.Throughout the peri‐implantation period, mouse uterine glands were active secretory structures in which the mode of secretion was similar to other exocrine cells. Thus, the uterine glands of the mouse must be considered a source of uterine fluid proteins at the time of implantation that may contribute to quantitative changes in these p

ISSN:0003-276X    

DOI:10.1002/ar.1091990111

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

年代:1981

数据来源: WILEY