摘要:

AbstractCat adrenal medulla was studied to determine whether or not an adrenergic nerve supply was available to medullary cells. The techniques used were those of routine electron microscopy, injection and uptake of “false” transmitter substance (5‐hydroxydopamine), injection of 6‐hydroxydopamine, which selectively destroys postganglionic adrenergic elements and a specific cytochemical method using glutaraldehyde and heavy metal techniques for cytochemical localization of biogenic amines. Each method consistently demonstrated adrenergic fibers and terminals in the adrenal medulla; these adrenergic elements contain dense, large core and small core vesicles which are not of the “dense cored” cholinergic type. Localization of adrenergic fibers and terminals is deemed significant since the latter had thebouton en passageconfiguration immediately adjacent to norepinephrine cells; adrenergic elements were not seen in close relationship to epinephrine cells. Consistency of the findings from the three techniques point to the fact that the norepinephrine cells of the adrenal medulla have a dual innervation, both cholinergic and adrenergic. This type of innervation pattern is not unique for the autonomic nervous system, but it has not been reported previously for adrenal medullary cells. It is believed that such an innervation pattern has functional and pharmacologic s

ISSN:0003-276X    

DOI:10.1002/ar.1091810402

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe cells of the upper strata of mammalian epidermis are flattened and aligned to form regular columnar units. It has been suggested that the position of the smaller underlying basal cells is related to the overlying cell columns. Examination of the position of metaphase figures in sheets of mouse epidermis indicated that mitosis occurs principally in cells lying just within the periphery of the cell columns but that there is no alignment of interphase basal cells within the columnar peripheries which could account for this position of mitosis.

ISSN:0003-276X    

DOI:10.1002/ar.1091810403

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

年代:1975

数据来源: WILEY

摘要:

AbstractPalatal processes from 14‐day fetal C57BL mice were cultured under varying conditions for 48 hours and prepared for light and electron microscopy. Disruption of the epithelium along the medial border occurred when single palatal processes were explanted onto Millipore filters, plasma clots, or lens paper in subjacent contact with nutrient medium. Paired processes under the same culture conditions demonstrated typical midline epithelial disruption and mesenchymal fusion. Regions of mesenchymal necrosis occurred in processes growth on nutrient agar in a dish or submerged in nutrient medium. In similar cultures medial epithelial disruption did not occur in single processes and mesenchymal fusion of paired processes was either delayed or did not occur. Disruption of the epithelium along the medial border in single palatal processes, and mesenchymal fusion in paired palatal processes, occurred when palates weregrown on nutrient agar supported above but in contact with nutrient medium. The results indicated that responses of palatal epithelium and mesenchyme may be altered by different in vitro procedures. These observations emphasize that many factors must be considered in interpreting developmental changes in palatal processes grown in vitr

ISSN:0003-276X    

DOI:10.1002/ar.1091810404

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe armadillo is rapidly emerging as an animal for biomedical research. A morphological study of the immune system of the armadillo was undertaken to try to demonstrate a possible defect in the morphogenesis of the lymphoid organs that could account for their susceptibility to leprosy. Blood from 20 domesticated adult armadillos revealed lymphocytes predominated among circulating leukocytes in the majority of animals, whereas in wild animals neutrophils predominated. Necropsies revealed well‐developed thymus glands and the thymus‐dependent areas in lymph nodes and spleens contained abundant lymphoid cells. Hence, we conclude that the susceptibility of the armadillo to leprosy cannot be explained on a morphological ba

ISSN:0003-276X    

DOI:10.1002/ar.1091810405

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe structural features of the development of the bursa of Fabricius in white Leghom chick embryos are depicted at carefully timed intervals during embryogenesis, with emphasis on the sequence of events between the ninth and twelfth days of incubation. The direction and character of the migration of lymphoid cell precursors and granulocytes from the intravascular space to intraepithelial sites, where the formation of the primitive lymphoepithelial nodule takes place, is demonstrated. The mechanism of the mode of migration of these cells through the stromal epithelial interface is described and illustrated with electron micrographs and their role in the development of the primitive lymphoid follicles is described and discussed.

ISSN:0003-276X    

DOI:10.1002/ar.1091810406

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

年代:1975

数据来源: WILEY

摘要:

AbstractNerves in the tongues of adult and immature rats were examined with respect to their permeability to exogenous cytochrome‐c (mol wt 12,000) injected into the tongue. The distribution of cytochrome‐c was determined in cryostat sections on the basis of the peroxidase activity of this protein. Nerves of 14‐day‐old rats were permeable to injected cytochrome‐c. The larger nerves of older animals showed only localized accumulations of cytochrome‐c reaction product both between and within axons adjacent to endoneurial blood vessels. Reaction product was not found, however, in association with blood vessels penetrating nerves of the tongue that were not within the limits of tracer spread. In the smallest nerve branches, thin linear strands of reaction product filled the interstices between the n

ISSN:0003-276X    

DOI:10.1002/ar.1091810407

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

年代:1975

数据来源: WILEY

摘要:

AbstractA method for inducing paralysis in embryonic chicks is described. This involves single injections of the neuromuscular blocking agents, D‐tubocurarine Chloride or decamethonium iodide, into 10‐day embryos. The dose which optimises survival and paralysis is determined along with the effect of the drugs on embryonic growth. Decamethonium iodide at a dose of 1 mg per embryo gave maximum survival and paralysis to 18 days of incubation. Paralysis was assessed by observation of treated embryosin ovoand by examination of embryos removed from their shells between 11 and 18 days of incubation. Embryos were completely paralysed 24 hours post‐injection and remained paralysed until 18 days of incubation. Paralysed embryos failed to hatch. Development of the leg musculature was severely retarded in paralysed embryos. This method of inducing paralysis has considerable advantages over previous continuous infusion methods. The growth and collagen content of the tibia in the paralysed embryos was reduced and these results, and other applications of the method, are disc

ISSN:0003-276X    

DOI:10.1002/ar.1091810408

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

年代:1975

数据来源: WILEY

摘要:

AbstractFollowing intravenous injection, cytochrome c traverses the capillary endothelium of the rat choroid plexus and permeates the perivascular space and the extracellular space between epithelial cells. The tracer is incorporated into pinocytotic vesicles adjacent to the lateral and basal plasmalemmas. There‐after, cytochrome c is incorporated into multivesicular and dense bodies. Tracerladen vesicles were not found to fuse with the apical plasmalemma and cytochrome c was not discharged into the cerebral ventricles. Acid phosphatase activity of the choroidal epithelium after the administration of cytochrome c was greatly increased and localized in the same intracellular sites shown for cytochrome c. These data suggest that cytochrome c and possibly other proteins that penetrate the choroidal stroma are taken up by the choroidal epithelium and subsequently degraded in lysosomal vesicles. This heterolytic mechanism may be an important means for preventing the entry of certain substances such as proteins into CSF and subsequently into nervous tissu

ISSN:0003-276X    

DOI:10.1002/ar.1091810409

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe first group norms on the periodic occurrence of tumescence in the perineal labia of female lowland gorillas were obtained in 9 captive subjects. Individual mean cycle lengths for 8 adult females in 2 experiments ranged from 25.9–36.3 days with overall means of 31.1 and 32.5 days. The one subadult female had a mean cycle length of 40.7 days. The median and modal duration of maximal labial tumescence were 1.8 and 1 day, respectively. Data from 3 animals on which menses were recorded during 6 cycles yielded relatively consistent postswelling phase durations of 8–11 days and durations of menstruation of 1–2 days. The data from 2 conceptions of 1 female suggested that time of ovulation was closely associated with the day of detumescence. These data are discussed in terms of certain differences as well as similarities which exist between the gorilla and its closest relative, the chimpanzee. The contribution of these data to the area of comparative reproduction is enhanced because of the significant taxonomic affiliations of the gorilla sp

ISSN:0003-276X    

DOI:10.1002/ar.1091810410

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

年代:1975

数据来源: WILEY

摘要:

AbstractTransection of a peripheral nerve not only elicits changes in the injured neurons but also results in an increase in non‐neuronal cells, considered by most workers to be neuroglia, in the region of these neurons. Since studies in this laboratory have shown that the neuroglial population of spinal cords of immature rats can be reduced markedly by ionizing radiation, the present investigation was undertaken to determine if this reaction would occur in the irradiated spinal cord following transection of the sciatic nerve. In order to answer this question the sciatic nerve was sectioned unilaterally at 17 days of age (14 days post‐irradiation). Sham‐irradiated littermates served as controls. Light microscopic examination showed an increase in non‐neuronal cells throughout the gray matter on the side of axotomy in spite of a decreased neuroglial population in the 2,000 R and 3,000 R groups. These cells were scattered in the neuropil or were adjacent to injured neuronal perikarya in the anterior horn. Qualitatively similar reactions occurred in the 500 R and 1,000 R groups and in shamirradiated controls. Whether the magnitude of response is the same in all groups is currently under investigation, as are questions dealing with the origins of the reactiv

ISSN:0003-276X    

DOI:10.1002/ar.1091810411

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

年代:1975

数据来源: WILEY