摘要:

AbstractHepatic glycogen patterns are described for rats adapted to a precisely controlled feeding schedule and ad libitum fed rats. Liver samples were processed for biochemical and histochemical glycogen analysis at precise intervals following a 22 hour fast and a 2 hour meal. Histochemical determination of glycogen (PAS) after freeze substitution showed lobular patterns of hepatic glycogen which correlate with chemically determined glycogen levels and nutritional states of the rats. After 22 hour fasting, hepatocytes from rats with low glycogen levels (5%). Glycogen depletion reduced glycogen staining in cells throughout the lobule, but centrilobular patterns prevailed until late in depletion when periportal patterns appeared. Ad libitum‐fed rats showed similar glycogen patterns except maximum deposition was characterized by centrilobular or even lobular distribution of glycogen, and periportal patterns of glycogen were seen only rarely in extreme fasted rats. Differences in lobular patterns between ad libitum and control fed rats is apparently related to lower maximum hepatic glycogen levels reached by ad libitum‐fed anim

ISSN:0002-9106    

DOI:10.1002/aja.1001400302

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

年代:1974

数据来源: WILEY

摘要:

AbstractFormation of the myelin sheath in peripheral nerve of the newborn rat is compared with its formation in postnatal cerebral white matter. The unmyelinated central axon is bare and myelination begins by the spiral wrapping of an oligodendrocytic process around the axon. The paired membranes of this process fuse on their inside surfaces, lengthen, and spiral around the axon to make a loose sheath of major dense lines. Compact myelin results after fusion of the outside surfaces to form the intraperiod line. Cytoplasm is sparse in developing central myelin, usually being restricted to inner and outer tongues.Unmyelinated peripheral axons are enclosed within a mesaxon formed by the invagination and fusion of the outside surfaces of the Schwann cell plasma membranes. Loose myelin is produced by lengthening and spiralling of the mesaxon (intraperiod line) around the axon. As Schwann cell cytoplasm is extruded from between the spirals, the major dense line forms and compact myelin results. Trapped cytoplasm, a characteristic of developing peripheral myelin, is found in the internodal compact myelin sheath as the inner and outer collars and the Schmidt‐Lanterman cleft

ISSN:0002-9106    

DOI:10.1002/aja.1001400303

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe response of the kidneys of 237 adult newts [Notophthalmus (Diemictylus) viridescens] to partial nephrectomy (15 to 30% of right kidney removed) and sub‐total nephrectomy (70 to 90%) was studied histologically and autoradiographically to determine their regenerative potential. The response involved both hypertrophy and hyperplasia as indicated by increases in3H‐thymidine labelled nuclei and also3H‐leucine incorporation by the remaining cells of the kidney. Leucine incorporation increased within 24 hours and continued to increase until 5 days after partial nephrectomy (17% increase over control level) or 15 days after sub‐total nephrectomy (36% increase). The number of thymidine labelled nuclei, however, did not increase for the first 5 days and then continued to increase up to 10 days after partial nephrectomy (to 3X control level) and 20 days after sub‐total nephrectomy (to 5X control level).An accumulation of cells appeared on the cut surface of the kidney by 15 to 20 days after nephrectomy. It consisted of modified epithelial cells from the tubules and was characterized by marked basophilia. The number of3H‐thymidine labelled nuclei in the accumulation increased about 10 to 20 times over control levels at its peak on days 12 to 15;3H‐leucine incorporation doubled at its peak on days 10 to 15. Nevertheless, after day 20 the cell accumulation decreased in size due to cell resorption or sloughing or both; it had disappeared by day 50 with no new tissue resulting. The newt kidney does not appear to exhibit any regenerative potential and, therefore, it is similar to mammalian kidneys in

ISSN:0002-9106    

DOI:10.1002/aja.1001400304

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

年代:1974

数据来源: WILEY

摘要:

AbstractReactions for hydrolytic enzymes such as aminopeptidase, β‐glucuronidase, N‐acetyl‐β‐glucosaminidase, arylsulfatase and non‐specific esterases indicated various degrees of activity within the chondrocytes of the young mandibular condyle. Most of the reaction products of the above enzymes appeared as discrete granules, which might indicate a lysosomal origin. The most intense activity of these enzymes was observed within chondroblasts and premineralizing hypertrophic chondrocytes. However, chondrocytes within the mineralizing zone also appeared synthetically active. The latter cells, as well as those at the adjacent ossification front, revealed some activity by a majority of the enzymes tested. This could indicate that some metabolic functions, although reduced in degree, continue in the cells of these mineralizing zones of endochondral ossification.Matrical reactions, with the exception of arylsulfatase and aminopeptidase, were essentially negative. The positive reactions for the latter enzymes might be an indication of their involvement in the process of extracellular min

ISSN:0002-9106    

DOI:10.1002/aja.1001400305

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

年代:1974

数据来源: WILEY

摘要:

AbstractIncubation of human oral mucosa in physiological solutions containing proteolytic enzymes permits separation of the preparation into its epithelial and connective tissue components. Trypsin, collagenase and elastase were utilized to effect epithelium‐connective tissue separation. Elastase was the most suitable in that a reliable separation of the epithelium from the connective tissue occurred at the lamina lucida (the electron‐lucent zone between the basal cell and basal lamina) with only minimal alteration of the epithelium. The most common change observed in separated epithelium was the formation of cytoplasmic protrusions or blebs on the inferior surface of the epithelial basal cell. Bleb formation was quite extensive when preparations were incubated one to two hours beyond the point where the epithelium could be separated from the connective tissue. With prolonged incubations inferior aspects of epithelial basal cells demonstrated the formation of an entirely new cytoplasmic front apparently resulting from fusion of membranes and subsequent confluence of the cytoplasm contained within the blebs. Individual hemidesmosomes or small lengths of the original inferior epithelial basal cell membrane became enclosed in membrane‐bound vacuoles within the cytoplasm of the epithelial basal cell. These vacuoles were shown to have been interiorized by the absence of a ruthenium red reaction product within the vacuolar spaces. Bleb formation was shown to be strictly enzyme‐induced since intact specimens demonstrated extensive basal cell blebbing following prolonged incubation. Occasional desmosomes were broken and the component halves interiorized in membrane‐bound vacuoles within the cell cytoplasm. Alterations observed in epithelial basal cells as a consequence of exposure to exogenous proteolytic enzymes mimic alterations observed in many disease processes and during certain stages of de

ISSN:0002-9106    

DOI:10.1002/aja.1001400306

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

年代:1974

数据来源: WILEY

摘要:

AbstractThe development of the fetal membranes of the North African jerboa (Jaculus) and the North American jumping mouse (Zapus) were examined by light microscopy, and the interhemal membrane ofZapuswas studied by electron microscopy. Early stages ofJaculusshow implantation to be antimesometrial with the embryonic disc oriented mesometrially. Amniogenesis is by folding and there is a distinct epamnionic cavity. Yolk sac inversion is complete, but the disappearance of the parietal segment occurs relatively late, during the early fetal period. Those early stages ofZapuswhich were available indicated a close similarity toJaculus. BothJaculusandZapusare unusual in the manner of development and composition of the chorio‐allantoic placenta. Development of cytotrophoblast and syncytiotrophoblast is arrested early and these layers eventually disappear. Trophoblastic giant cells migrate into the allantoic mesenchyme to form the maternal blood channels of the labyrinth. InJaculus, a complex interdigitation exists between yolk sac villi and arterial channels bringing maternal blood to the labyrinth. This relationship is much less intimate and extensive inZapus. Electron microscopic examination of the interhemal membrane ofZapusshows it to be hemomonochorial, its only trophoblastic element being the giant cell cytoplasm. Thus, theZapusplacenta is to date one of very few hemochorial placentas known to lack trophoblastic syncytium in its interhemal membrane. Comparison of the total development and structure of the fetal membranes in these two genera with that of other rodents indicates that the membranes of the Dipodoidea, like the Geomyoidea, are intermediate in type between those of the Sciuromorpha and Myomorph

ISSN:0002-9106    

DOI:10.1002/aja.1001400307

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

年代:1974

数据来源: WILEY

摘要:

AbstractRecent chemical studies have indicated that the chondroitin sulfate proteoglycan of cartilage interacts with hyaluronic acid to form high molecular weight aggregates. In the present study, morphological evidence has been obtained that this interaction represents a physiologically occurring phenomenon, as indicated by the finding that the proteoglycan particles disappear from tissue sections on digestion with a hyaluronidase from Streptomyces hyalurolyticus, which is specific for hyaluronic acid.

ISSN:0002-9106    

DOI:10.1002/aja.1001400308

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

年代:1974

数据来源: WILEY

摘要:

AbstractMouse trigeminal neurons contained a cytoplasmic inclusion consisting of a dense particle (diameter ∼ 100 nm.) surrounded by a smooth surfaced membrane sometimes in continuity with the rough surfaced endoplasmic reticulum. The identity of the inclusion is uncertain but it may be related to intracisternal A type particle

ISSN:0002-9106    

DOI:10.1002/aja.1001400309

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

年代:1974

数据来源: WILEY

摘要:

AbstractUsing an immunohistochemical technique at the electron microscopic level, we have observed that growth hormone‐release inhibiting hormone (somatostatin), the hormone which inhibits the release of growth hormone, is contained in the secretory granules of many nerve endings mainly located in the external zone of the median eminenc

ISSN:0002-9106    

DOI:10.1002/aja.1001400310

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

年代:1974

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001400301

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

年代:1974

数据来源: WILEY