摘要:

AbstractThe mucosal covering of the cartilaginous portion of the cat trachea was studied by correlated light, transmission‐electron, and scanning‐electron microscopy. While in some areas the ciliated pseudostratified epithelial lining is fairly smooth in contour, in other areas it contains longitudinally oriented, cilia‐lined clefts. Ducts from submucosal glands sometimes open into the base of these clefts, or into funnel‐shaped stomata that are lined by either ciliated or microvillus‐rich cells. Specialized epithelial cells are occasionally associated with the clefts or with other regions of surface epithelium. In single sections, these cells appear to contain a cilium‐lined vacuole, but serial sectioning has demonstrated that these apparent vacuoles actually are long intracellular inaginations in enormously elongated cells that extend longitudinally in the plane of the epithelium. The function of these cells is undetermined. Basal cells are attached to the lamina densa by means of hemidesmosomes that consistently lack peripheral densities; in contrast, the tall columnar cells have no hem

ISSN:0002-9106    

DOI:10.1002/aja.1001680202

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

年代:1983

数据来源: WILEY

摘要:

AbstractBronchoscopic examination of anesthetized cats revealed that the trachea is capable of considerable change in caliber via lateral expansion of the membranous trachea. The morphological basis for this expansile capacity was determined by correlated light microscopy and scanning and transmission electron microscopy. The organization of the membranous trachea differs from that of the cartilaginous trachea. The mucosa is arranged in a series of longitudinal folds that open like an accordion when stretched laterally. These fold are not random, but appear to depend on rows of nonciliated, microvillusrich cells that form flexure lines in the surface epithelium. The mitochondria in such cell have a condensed configuration, indicating a high level of oxidative metabolism and suggesting that they may participate in transport processes that modify the luminal contents. Goblet cells, which are relatively sparse in the membranous trachea, have mitochondria in which the prominence of matrix granules and degree of mucus storage are inversely related. Mitochondrial morphology allows goblet cells that have discharged their mucin content to be readily distinguished from the microvillus‐rich cells, even when their luminal surfaces lie outside the thickness of a sectio

ISSN:0002-9106    

DOI:10.1002/aja.1001680203

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe morphological relationships between the superficial and deep pineal glands of neonatal Syrian hamsters are described at both light and electron microscopic levels. In addition, melatonin contents in the two glandular masses are compared throughout a 14 hr light:10 hr dark photoperiod in 20‐day‐old hamsters. It has been found that the pineal anlage begins to separate into deep and superficial components between the first and third postnatal days of life. Separation is usually complete by day 12. The fine structure of the deep gland is similar to that of the superficial gland throughout development. By the time of weaning (20 days of age), the young hamsters exhibit distinct nighttime elevations of melatonin in both the superificial and deep glands, the quantities in the deep gland being approximately 5% those of the superficial pineal. Like that of the superficial pineal, the rise in deep pineal melatonin content can be abolished by exposure of hamsters to li

ISSN:0002-9106    

DOI:10.1002/aja.1001680204

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe medial nucleus of the trapezoid body (MNTB) appears to be a prominent auditory structure in many mammals. However, the presence of an MNTB in the human brain has not been clearly established. One of the most characteristic features of the cat MNTB is the presence of large somatic endings with multiple synaptic sites, the calyces of Held. We examined adult human brains at both light and electron microscopic levels and found neurons with unusually large endings in a location that is similar to that for the MNTB in other animals. Moreover, the sizes and shapes of some cells in this area are similar to the principal cells of the cat MNTB. These observations support the idea that humans have cells that resemble MNTB neurons in other species. It has been suggested that the cat MNTB may be involved in the generation of wave 3 of its brainstem auditory evoked potentials, so the presence of an MNTB in the human brain may have implications in interpreting brainstem potentials in man.

ISSN:0002-9106    

DOI:10.1002/aja.1001680205

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

年代:1983

数据来源: WILEY

摘要:

AbstractTo examine whether collagen is assembled into fibrils within or outside fibroblasts, the connective tissue of the rat foot pad was investigated by electron microscopy and by radioautography at times varying from 4 min to 3 days after an intravenous injection of3H‐proline.The fibroblasts of the rat food pad are long polarized cells with the nucleus at one end, the Golgi apparatus in the center, and a region with long processes at the other end. This region contains secretory granules and is considered to be the secretory pole of the cell. In the Golgi apparatus the stacks of saccules are separated from rough endoplasmic reticulum (rER) by groups of “intermediate vesicles” including similarly structured tubules which may be over 300 nm long and are referred to as “intermediate tubules”. The Golgi saccules exhibit distended portions which differ at the various levels of the stack. On the cis side, the distentions tend to be spherical and contain fine looping threads; in the middle of the stack, they are cylindrical and present distinct straight threads; whereas on the trans side, they are again cylindrical, but the straight threads are grouped in parallel aggregates. Between these cylindrical distentions and the secretory granules, there are transitional forms within which thread aggregates are packaged more and more tightly. Finally, the fibroblasts are associated with two types of collagen fibrils: extracellular ones arranged into large groups between the cells and intracellular ones located within long intracytoplasmic channels.Quantitative radioautography after3H‐proline injection reveals that the number of silver grains per unit area reaches a peak over the rER at 4–10 min, Golgi apparatus at 40 min, secretory granules at 60 min, and extracellular collagen fibrils at 3 h. At no time are intracellular collagen fibrils labeled. Qualitative observations further indicate that spherical Golgi distentions are mainly labeled at 40 min, and cylindrical distentions, at 60 min. In addition, from 20 min to 3 hr, some lysosomal elements are labeled.The biogenetic pathway leading to the formation of collagen fibrils is interpreted as follows. Collagen precursors arise in the rER and, by way of intermediate tubules or vesicles, reach the spherical Golgi distentions. These seem to migrate in a trans direction, while they become cylindrical and their looping threads straighten out into rods which have been identified as procollagen. The cylindrical distention is then freed from its saccule to become a secretory granule. The procollagen content of the granule is released outside the cell and presumably transforms into collagen which then polymerizes into fibrils. Thus, except for a minor fraction of the labeled precursors deviated toward the lysosomal pathway, the bulk of them give rise to collagen, which is added to the extracellular fibrils and, therefore, provides for their growth. No collagen is incorporated into the intracellular collagen fibrils, which, therefore, do not grow, but often undergo degeneration. Thus, the assembly of collagen into fibrils does not occur within cells but is entirely

ISSN:0002-9106    

DOI:10.1002/aja.1001680206

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

年代:1983

数据来源: WILEY

摘要:

AbstractM cells in Peyer's patch follicle epithelium endocytose and transport luminal materials to intraepithelial lymphocytes. We examined (1) enzymatic characteristics of the epithelium covering mouse and rat Peyer's patches by using cytochemical techniques, (2) distribution of lectin‐binding sites by peroxidase‐labeled lectins, and (3) anionic site distribution by using cationized ferritin to develop a profile of M cell surface properties. Alkaline phosphatase activity resulted in deposits of dense reaction product over follicle surfaces but was markedly reduced over M cells, unlike esterase which formed equivalent or greater product over M cells. Concanavalin A, ricinus communis agglutinin, wheat germ agglutinin and peanut agglutinin reacted equally with M cells and with surrounding enterocytes over follicle surfaces. Cationized ferritin distributed in a random fashion along microvillus membranes of both M cells and enterocytes, indicating equivalent anionic site distribution. Staining for alkaline phosphatase activity provides a new approach for distinguishing M cells from enterocytes at the light microscopic level. Identical binding of lectins indicates that M cells and enterocytes share common glycoconjugates even though molecular groupings may differ. Lectin binding and anionic charge similarities of M cells and enterocytes may facilitate antigen sampling by M cells of particles and compounds that adhere to intestinal surfaces in non‐Peyer's patch

ISSN:0002-9106    

DOI:10.1002/aja.1001680207

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe development and maintenance of the Sertoli cell junctional complex were investigated in prepubertal and adult guinea pigs. To correlate the structure of the blood‐testis barrier with its permeability, the polyene antibiotic filipin (a cholesterol‐binding agent of low molecular weight: 570.70) was added to the fixative as a tracer visible in freeze‐fracture replicas. Discontinuous zonules, intermediate junctions (i.e., adhering fasciae) and gap junctions all proved permeable to filipin in the two age groups. Only the continuous occluding zonules characteristic of the adult guinea pig's testis were impermeable to the tracer.In pubertal animals, the establishment of the blood‐testis barrier coincided with the completion of the junctional strands in occluding zonules. The formation of occluding zonules was similar in the newborn and the adult. In the adult, the Sertoli cell junctional complexes contained three types of cell junctions: occluding, adhering, and gap junctions. The sequence of occluding and adhering junctions from the base to the apex of the epithelium was the reverse of that demonstrated in most epithelia. The impermeable continuous occluding zonules at the base showed parallel patterns of uninterrupted junctional strands, whereas the permeable discontinuous zonules found higher in the epithelium showed a meandering pattern of broken strands.Our observations indicate that (1) Sertoli cell junctional complexes form near the young germinal cells at the base of the seminiferous epithelium and break down near the older germinal cells toward the apex; (2) the various patterns and orientations of the junctional strands reflect, respectively, the different stages of disintegration of the occluding zonules and the conformation of the mature Sertoli cell to the irregular contours of the germinal cells; (3) there is no relationship between permeability and junctional strand orientation; and (4) the cellular contacts between Sertoli cells and germinal cells situated below the blood‐testis barrier may represent the early stages of formation of junctional elements which ultimately become incorporated into the Sertoli cell junctiona

ISSN:0002-9106    

DOI:10.1002/aja.1001680208

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

年代:1983

数据来源: WILEY

摘要:

AbstractUsing the technique of in vitro steroid autoradiography, the localization and modulation of nuclear estrogen binding sites has been studied in normal human cervix and vagina during the menstrual cycle, pregnancy, and the menopause. Marked differences occur in nuclear estrogen binding between these two organs. Nuclear estrogen binding varies throughout the menstrual cycle in the vaginal epithelium, whereas vaginal stromal cells consistently exhibit nuclear estrogen binding throughout the cycle. In contrast, the cervical squamous and columnar epithelia show much less cyclic variability in nuclear estrogen binding sites. As in the vagina, the cervical stroma consistently binds estrogen. High levels of nuclear estrogen binding sites are found in the vagina of the postmenopausal patient, and lower levels of binding occur postpartum. The implications of these localizations, with special reference to the role of the cervical and vaginal stroma, are discussed.

ISSN:0002-9106    

DOI:10.1002/aja.1001680209

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

年代:1983

数据来源: WILEY

摘要:

AbstractThe several cell types in mouse and rat rectosigmoid colon have been examined with light and electron microscopic methods for localizing and characterizing complex carbohydrates. Mucous cells, also termed vacuolated cells, and goblet cells comprised most of the deep crypt epithelium in both species, and absorptive columnar cells and goblet cells mainly populated the more superficial epithelium of the upper crypts and main lumen. Occasional tuft cells and enteroendocrine cells were also encountered.Transitional cells structurally intermediate between mucous cells and absorptive cells contained granules characteristic of mucous cells and vesicles like those of columnar absorptive cells. These intermediate cells supported the concept of replacement of mucous by absorptive cells through transformation of mucous into absorptive cells. The intermediate cells also contained numerous lysosomes often in apparent fusion with mucous granules, indicating crinophagic disposal of mucous granules as a mechanism in the cell transformation. Glycoconjugate in absorptive cell vesicles resembled that coating the apical plasmalemma and appeared to represent the source of the glycocalyx of the brush border. Complex carbohydrate in these vesicles differed cytochemically from that of the mucous cell granules, which release their content into the crypt lumen. The absorptive cell vesicles, therefore, constitute an organelle distinct from the mucous cell granules rather than an atrophic form of the latter in a more mature cell.Goblet cells differed in failing to transform morphologically with age but changed in the cytochemical characteristic of their secretion during migration up the crypts. Terminal N‐acetylglucosamine residues diminished, while terminal sialic acid‐galactose dimers increased during the upward migration, indicating activation of glycosyl transferase synthesis in relation to goblet cell maturation.Glycoconjugate in secretion of mucous cell granules differed markedly from that in goblet cell granules, and content of both organelles differed from that of absorptive cell vesicles. However, secretion in mucous cell granules appeared generally similar for mice and rats with minor exceptions, and secretion in goblets of mice generally resembled that in goblets of rats. Cells interpreted tentatively as Kulchitsky cells stained for high content of fucose with theUlex europeusI lectin. Globoid leukocytes infiltrating the epithelium of the rat but not the mouse rectosigmoid colon resembled globoid leukocytes in rat tracheal epithelium and, like the latter, appeared to derive from mast ce

ISSN:0002-9106    

DOI:10.1002/aja.1001680210

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

年代:1983

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001680201

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

年代:1983

数据来源: WILEY