ISSN:0003-276X    

DOI:10.1002/ar.1091780102

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

年代:1974

数据来源: WILEY

摘要:

AbstractPhagocytosis of supernumerary spermatozoa contained within the perivitelline space was observed in 7 of 28 two‐cell mouse embryos cultured for 45 hours post‐insemination (approximately 20–24 hours after cleavage). The spermatozoa were incarcerated as a result of elevations of the blastomere cytoplasm which gradually surrounded the sperm, overlapped and fused, thus forming a typical phagocytic vacuole. Phagocytosis was not observed in two‐cell embryos cultured for less than 20–24 hours after cleavage; this indicates that the blastomeres of two‐cell mouse embryos in vitro require approximately 24 hours to develop one of the characteristics of somatic cells, i.e., the ability to recognize and phagocytize forei

ISSN:0003-276X    

DOI:10.1002/ar.1091780103

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe urinary bladder of the bullfrog,Rana catesbianahas been studied by light and electron microscopy. Three epithelial cell types were found: (1) granular cells, (2) mitochondria‐rich cells, and (3) basal cells. The structure of theRana catesbianabladder differs from that of the toadBufo marinus, in several respects: it lacks a mucous (goblet) cell type, its granular cells do not contact the underlying basement membrane, it has specialized, smooth‐muscle cell‐basal epithelial cell contacts, not previously described in amphibian bladders, and its mucosa is richly innervated. Mitochondria‐rich cells within the bullfrog bladder epithelium were occasionally observed touching the basement membrane. The specialized smooth muscle‐basal cell contacts provide anatomical evidence for how regulatory vasoactive substances such as neurohypophyseal peptides might alter epithelial geometry. Many nerve endings invest the mucosa just beneath the epithelial basement membrane in proximity to mitochondriarich cells and basal cells. The possible role of neural regulation in epithelial transport was

ISSN:0003-276X    

DOI:10.1002/ar.1091780104

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

年代:1974

数据来源: WILEY

摘要:

AbstractThis report compares the arterial supply of the lumbo‐sacral spinal cord in the monkey with that of man. The arterial supply to the lumbo‐sacral cord of 100 monkeys (82 Rhesus and 18 Mangabey) was demonstrated by perfusion techniques. We tabulated the level and side of origin of the great anterior medullary artery. Previous authors have shown that in man the peak incidence of the great anterior medullary artery is at T‐10. The peak incidence in the monkey is at L‐1. There are other features of the arterial supply to the lumbo‐sacral cord of the monkey that are different

ISSN:0003-276X    

DOI:10.1002/ar.1091780105

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe chloride cells of the lamprey,Lampetra japonica, have been studied by electron microscopy. The most characteristic feature of the chloride cells in lamprey is that the cytoplasm is filled with a large number of mitochondria and numerous agranular cytoplasmic tubules arranged as bundles or as branched reticular networks. These tubules are frequently continuous with the plasma membrane. They are also characterized by a coating on the cisternal surfaces with a dense material which appears ridge‐like at high magnification. These ridges are oriented spirally along the cisternal surface of the tubule. They are regularly spaced at an interval of about 160 Å and have a pitch of about 45°. The functional significance of the cisternal coat is unknown. Sometimes, intracisternal tubules are observed to be contained within the lumina of the agranular cytoplasmic tubules. These intracisternal tubules are considered to be formed by an intracisternal deflection of only one leaflet of the unit membrane of the agranular cytoplasmic tubules. Membrane fusion is observed to occur between closely associated agranular cytoplasmic tubu

ISSN:0003-276X    

DOI:10.1002/ar.1091780106

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe I segment length has been measured and the number of thin filament periods per I segment has been counted in electron micrographs of Rhesus monkey and human leg muscle fibers. The number of I segment periods in the monkey fiber (60) and in the human fiber (66) multiplied by axial periodicity (385 Å) in thin filaments of living fibers (Huxley and BROWN, '67) plus 1,000 Å allowed for Z line width in living fibers, provided a formula for calculation of I segment lengths in living fibers. The calculated I segment lengths are 2.41 μ for the monkey and 2.64 μ for the human fiber. The ratio of calculated I segment length over an assumed constant thick filament length (1.6 μ) among vertebrates is in close agreement with the ratio of measured I segment length over measured thick filament length in micrographs of frog, rat, monkey and human leg muscle fibers. The calculated I segment length in the frog (1.95 μ) is compared with that of the human (2.64 μ) to show the relation of I segment length to the length‐developed tension diagram and to the series elastic components of the skeletal musc

ISSN:0003-276X    

DOI:10.1002/ar.1091780107

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

年代:1974

数据来源: WILEY

摘要:

AbstractAn initial study of the effects of long‐term ovariectomy on fimbrial and ampullar epithelia from rabbit oviducts has been made with the scanning electron microscope. Several of the rabbits were given estradiol benzoate before they were killed. These observations were compared with those of epithelial cells from similar oviductal segments from post‐ovulatory rabbits that served as controls.Fimbriae from oviducts of control animals were densely ciliated, partially concealing the bulbous processes of the secretory cells. In the ampullae the processes of the secretory cells were the predominant structure, their bulbous apices rising frequently above the tips of the cilia.When rabbits had been spayed for 16–18 months, the epithelial cells of both fimbriae and ampullae showed a remarkable change. A few cilia in small clumps were scattered among the secretory cells. The free surface of the secretory cells had become flattened and hexagonal in shape. Their microvilli were short, and from the center of each cell a thick, stubby central cilium protruded.Estrogen given the long‐term spayed rabbits caused almost complete reciliation as well as restoration of the bulbous processes of the secretor

ISSN:0003-276X    

DOI:10.1002/ar.1091780108

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

年代:1974

数据来源: WILEY

摘要:

AbstractPostnatal maturation of nonmyelinated fiber bundles (Schwann bundles) was studied in the sciatic nerves of Snell's dwarf mice. The homozygous recessive of this strain has been previously shown to be characterized by multiple pituitary hormone deficiencies and secondary hypothyroidism.In the normal littermates a reduction occurred between 10 and 14 days in the number of fibers per fascicle, or subdivision, of each Schwann bundle, and by 26 days nearly all of the axons were separately embedded in cytoplasmic furrows of their associated Schwann cells. Only a few large fascicles were seen in normal sciatic nerve specimens at 26 and 50–53 days. In contrast, fiber bundle fascicles in the mutant nerves were still represented, even at 50–53 days, by numerous tightly‐packed axons, as seen in the immature nerves at 10–12 days post‐partum.On the basis of the dwarf's physiological background, these results suggest an involvement of the endocrine system during later stages of peripheral nerve maturation. The possible mechanisms affected by postnatal endocrine deficiency and thereby leading to delayed segregation of nonmyelinated fibers within Schwann bundles are

ISSN:0003-276X    

DOI:10.1002/ar.1091780109

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe effects of blinding on cellular structure and porphyrin pigment content were studied in Harderian glands of pinealectomized and non‐pinealectomized adult female golden hamsters. Uterine weights were used as a criterion for pineal activity. Five weeks post‐operatively, no significant changes were observed in the Harderian glands or in the uterine weights of animals in either group. Eleven weeks post‐operatively, the blinded hamsters with intact pineal glands had significantly lowered uterine weights and Harderian glands that exhibited diminished amounts of porphyrin pigments and cellular characteristics of the male hamster. Harderian glands and reproductive organs from the 11‐week blinded‐pinealectomized hamsters did not differ from those of untreated

ISSN:0003-276X    

DOI:10.1002/ar.1091780110

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe morphogenesis of cerebellum has been studied in 6–19 day old chick embryos after a single injection of 0.05 mg of cyclophosphamide into the yolk sacs on the fifth day of incubation. Besides degeneration of Purkinje cells, rate of development was markedly retarded as evidenced by late appearance of the fissures and folia of the cerebellum. Purkinje cells remained disorganised up to 18 days of incubation, though in controls they were arranged in a single line by the fifteenth day. The thickness of the external granular layer increased and persisted for a longer period in the treated embryos. The cytoarchitecture returned to normal on nineteenth day of incubation, but the size of the cerebellum was significantly smaller than that of controls (P<0.001). Such transient disorganisation of the morphogenetic events in the neural tube may lead to inadequate and defective induction of surrounding mesenchyme, thereby resulting in defective skull formation through which the brain can herniate, i.e., exencephaly as reported in our earlier studies after cyclophosphamide administration in chicks (Singh et al., '71; Singh and Gupta, '72) and rats (Singh et al., '72

ISSN:0003-276X    

DOI:10.1002/ar.1091780111

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

年代:1974

数据来源: WILEY