摘要:

AbstractForty‐eight chick embryos were killed at 9–16 days of incubation age. Tissue was obtained from the fourth or fifth cervical vertebra, immersed in Karnovsky's fluid, post‐fixed in osmium tetroxide, dehydrated in ethanol, stained “en bloc” with uranyl acetate in ethanol, and embedded in Epon 812. Vertebrae were oriented for cross‐sectional microtomy in cephalic to caudal sequence. Thin sections were stained with uranyl and lead salt solutions saturated with tribasic calcium triphosphate to prevent decalcification.Chondrocytes within the cartilaginous vertebral body occur in various stages of degeneration without orderly arrangement. Both reversible and irreversible stages are found at the cartilaginous resorption front. Electron‐lucent osteoid and mineralization appear in the intercellular matrix at about 12.5 days. Rapidly invading blood vessels form a highly variable resorption front and irregular marrow cavity. Capillaries with accompanying cells border on the front, but else‐where open capillaries allow blood elements to be in direct contact with cartilage. Chondroclasts are associated with small areas of calcified cartilage. At about 14 days trabeculae are formed at the resorption front by osteoblasts which deposit bone osteoid on uncalcified cartilaginous matrix. The matrix is eroded away. A free trabecula of bone without a core of calcified cartilaginous matrix remains.Basic differences between developmental growth processes in the epiphyseal plate and vertebral body may stem from the large amount of uncalcified cartilaginous matrix at the latter's r

ISSN:0002-9106    

DOI:10.1002/aja.1001400402

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

年代:1974

数据来源: WILEY

摘要:

AbstractKnowledge of placentation in bears has been limited to analysis of a single shed placenta of the European brown bear. It was shown that the mature allantoic placenta is discoidal, endotheliochorial, provided with a circular marginal hematoma, and that the allantoic sac is large and permanent. The present study, based on a small series of conceptuses younger than any previously examined, provides new details concerning implantation and the morphogenesis of the fetal membranes, placenta and paraplacental organs. Implantation in the black bear is central and superficial; the orientation of the embryonic disc is antimesometrial. Amniogenesis and chorion formation are almost certainly accomplished by folding. The decidual reaction is minimal. As in other carnivores the yolk sac is prominent early, but progressively declines. A well‐developed choriovitelline placenta is formed early, but is eliminated before the limb bud stage. The bilaminar omphalopleure persists only slightly beyond the limb bud stage. The allantois, however, is extensive and permanent. Initially, the allantoic placenta is cup‐shaped but eventually flattens out to form the discoidal placenta. It is lobuliform and endotheliochorial, and probably a marked attenuation of the interhemal membrane occurs in later stages. The marginal hematoma, which is completed before the limb bud stage, is formed by enlargement and coalescence of separate extravasations, and apparently remains fully functional to term. Overall, morphogenetic sequences and relationships in bears more nearly resemble those of the dog than of other carnivo

ISSN:0002-9106    

DOI:10.1002/aja.1001400403

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe fine morphology of the choledocho‐duodenal junctions of dogs and cats was studied by means of microdissection, classical histological staining techniques and by demonstrating in serial sections non‐specific cholinesterases, which stain the smooth muscle components excellently. The inbuilt cholinergic nervous apparatus was studied in serial sections by demonstrating acetylcholinesterase. By combining these methods, the three‐dimensional structural arrangement of the intrinsic cholinergic innervation system, with reference to the various substructures to be innervated, could be studied and mapped in detail.The most important features in the morphology, with respect to the function, were the tapering of the terminal ductus choledochus into a nozzle, the existence of concentric retrograde saccules around the ampulla and the intramural part of the bile duct, and the complex construction of the sphincters. Normally such a structure makes possible an active suction‐pressure pumping for evacuation of bile and pancreatic juice, being at the same time effective in preventing regurgitation of the duodenal fluid. On the contrary, if the orificium of the ampulla is obstructed, this structural arrangement probably facilitates regurgitation, especially into the pancreatic duct.The intrinsic cholinergic nervous apparatus of the choledocho‐duodenal junction was extremely rich, especially if compared with the cholinergic innervation of the muscular layer of the gut wall. This can probably be considered as an indication of complex motor (and possibly associated sensory) functions of the sphincters, in contrast to only slow gross contractions of the gut.To summarize: both morphological and neuroanatomical bases seem to be provided for rhythmic suction‐pressure pumping as well as for sensitive protective reflex functions in the choledocho‐duodenal junctions of the dog and cat. The finely graded complex interactions of the various muscle components are regulated by connecting and integrating neural elements between the individual smooth

ISSN:0002-9106    

DOI:10.1002/aja.1001400404

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe intent of this experiment was to determine whether with an increase in ocular mass there would be an increase in orbital volume. Eighteen, four‐week old, 220 to 420 gm Dutch rabbits were used. In 12 animals silicone was injected into one eye but not the opposite one. No silicone was injected into the eyes of six untreated rabbits. In a ten week period the total amount of ten silicone injections into each treated eye ranged from 1.2 to 1.6 ml. After each rabbit was euthanatized, elastic rubber base imprints were made of both cleaned orbits to determine the volumes. In the untreated animals the differences between the right and left orbital volumes ranged from — 0.1 to 0.2 ml (— 2.4 to 4.7%). The mean of the differences was not statistically significant. When the eyes were injected with silicone, the differences in orbital volumes between the injected and non‐injected sides ranged from 0.6 to 0 ml (14.6 to 0%). The mean of the differences was 0.3 ml which is statistically significant. It was concluded that periodic intrabulbar injections of silicone in the growing rabbit significantly increased orbital

ISSN:0002-9106    

DOI:10.1002/aja.1001400405

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

年代:1974

数据来源: WILEY

摘要:

AbstractSpecial lamellated bodies, 400 to 700 Å in diameter, are observed in the adepidermal space at the epidermal‐dermal junction of the skin of the frog tadpole,Rana rugosa. Each stained lamella is about 20 Å thick and separated from adjacent lamellae by spacings of 20 to 30 Å. The lamellated bodies are demonstrated in specimens prepared with phosphotungstic acid (PTA)‐containing fixatives, but are not revealed in specimens fixed with ordinary aldehyde fixatives which lack PTA. They are sometimes observed within the cytoplasm of basal epidermal cells, suggesting their epidermal origin. Far less frequently, comparable structures are present outside the sarcolemma of skeletal muscle fibers. Three kinds of anchoring structures are observed at the epidermal‐dermal junction: anchoring filaments, anchoring fibrils, and anchoring fibers. The anchoring filaments are observed in the adepidermal space connecting hemidesmosomes to the basal lamina. They are 200 to 230 Å in diameter and have no banding pattern. Anchoring fibrils, 210 to 250 Å thick and unbanded, are present in the upper one‐third of the collagenous lamellae. Fibrils do not have a banding pattern. Direct continuity between anchoring fibrils and anchoring filaments is suggested. Anchoring fibers, about 170 mμ, thick, occur less frequently. They are composed of laterally aggregated finer fibrils which show no clear bandings. Their distal ends join with the basal lamina and they extend proximally deep into the collage

ISSN:0002-9106    

DOI:10.1002/aja.1001400406

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

年代:1974

数据来源: WILEY

摘要:

AbstractPeripheral blood lymphocytes from three patients with defective differentiation of B cells were studied by routine electron microscopic techniques. One patient had severe combined immunodeficiency with rudimentary development of the B cell line. Two had immune deficits secondary to the B cell malignancy, chronic lymphocytic leukemia. Accumulations of tuboreticular structures were found in the cytoplasm of lymphocytes from the severe combined immune deficiency patient, sometimes in close association with annulate lamellae. The tuboreticular structures resemble those described in lymphocytes and endothelial cells of patients with systemic lupus erythematosus. In one patient with chronic lymphocytic leukemia, cylindrical arrangements of ribosomal material occupied the cytoplasm of many lymphocytes. These cylinders were observed in samples of blood drawn at different times and after tissue culture of lymphocytes with and without pokeweed mitogen. The other patient with chronic lymphocytic leukemia had circulating lymphocytes with material identified as IgM in the perinuclear spaces and dilated cisternae of the rough endoplasmic reticulum. This material sometimes had a crystalline structure.These observations indicate that in some cases functional immunological deficits in B cells, manifested by failure to differentiate to mature secretory cells, may be correlated with morphological aberrations of protein‐manufacturing organelles within the cel

ISSN:0002-9106    

DOI:10.1002/aja.1001400407

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe Karnovsky cholinesterase stain was used to map the positions of the myoneural junctions distributed over the inner surface of three frog sartorius muscles. In each preparation end‐plates were seen to occur in clusters, predominantly associated with fine myelinated nerve fibers in proximity to the larger nerve branches. No myoneural junctions were observed in the extreme proximal or distal regions of the muscles. Although more junctions were found in the regions proximal to the point of nerve entry into the sartorius muscle, terminals were more consistent in their location in areas distal to this point. End‐plate configurations varied appreciably in length, branching and complexity, but the majority of the terminal nerve processes extended parallel to the long axis of the muscle fib

ISSN:0002-9106    

DOI:10.1002/aja.1001400408

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe fate of cortical granules was ascertained in cold‐shock activated rabbit eggs. Unfertilized oocytes were obtained 14 hours after intravenous injection of Human Chorionic Gonadotropin. Experimental oocytes were stored at 6 to 10°C for 24 hours in F10 medium containing 10% rabbit serum. Control oocytes, and the experimental ones subsequent to cold‐shock treatment, were incubated for 24 hours. Formation of ‘pronuclei’ occurred in 6% of the cold‐shock treated oocytes. None of the control oocytes were activated. Electron microscopic observations show that activation occurred without the dehiscence of cortical granule content into the perivitelline space. Cortical granules were dispersed in the cytoplasm or clumped together at the periphery. Occasionally, cortical granules were found discharged into the perivitelline space with the limiting membr

ISSN:0002-9106    

DOI:10.1002/aja.1001400409

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

年代:1974

数据来源: WILEY

摘要:

AbstractUsing an immunoperoxidase technique at the ultrastructural level, vasopressin was localized in the axons of both the supraoptic and paraventricular nuclei, in the internal zone of the median eminence and the posterior pituitary but not in the perikarya of the neurosecretory neurons. A complete absence of histochemical reaction was found in the hypothalamo‐neurohypophyseal tract of the rat with hereditary hypothalamic diabetes insipidus (Brattleboro strain

ISSN:0002-9106    

DOI:10.1002/aja.1001400410

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe distribution of neurons which concentrate testosterone or its metabolites in the brain of 2‐day old female rats was determined using autoradiography. A specific topographic pattern of neurons which concentrate testosterone or its metabolites was obtained similar, but not identical, to the one found in adult male rats. The demonstrated sites of nuclear uptake and retention of testosterone or its metabolites by specific neurons in the neonatal brain probably provide the anatomical substrate for sexual differentiation of the brai

ISSN:0002-9106    

DOI:10.1002/aja.1001400411

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

年代:1974

数据来源: WILEY