摘要:

AbstractAnalysis of electon microscopic radioautographs revealed a maximum labeling with3H‐proline of rough endoplasmic reticulum (RER) at 3 minutes, Golgi saccules 1 and 2 at 10 minutes. Golgi saccules type 3 at 20 minutes, and presecretory and secretory granules at 30 minutes. Labeling of the extra‐cellular collagen matrix occurred at 30 minutes and increased with time. These observations suggest that pro‐a‐chains of collagen in periodontal ligament fibroblasts are synthesized in the RER and transported to the Golgi apparatus within 10 minutes. These chains then undergo parallel alignment in Golgi saccules type 2 and form segment‐long‐spacing‐like crystallites in Golgi saccules type 3 between 10 and 20 minutes. The peak labeling of presecretory granules and mature secretory granules in small amounts at 30 minutes and the rapid increase in labeling of extracellular collagen matrix which begins at 30 minutes, indicates that the formation of secretory granules requires approximately 30 minutes and that a rapid system of secretory granule translocation exists in periodontal ligament fibroblasts. This evidence futher supports the previously published morphologic evidence for a microtubuledependent system of collagen secretion in periodontal ligament fibroblasts (Cho and G

ISSN:0003-276X    

DOI:10.1002/ar.1092010402

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

年代:1981

数据来源: WILEY

摘要:

AbstractColchicine administered intravenously depolymerized microtubules and disrupted the normal organization of the Golgi apparatus in periodontal ligament fibroblasts. Radioautography with3H‐proline indicated that collagen secretion was completely inhibited during a period of approximately 4 hours following the onset of the colchicine effect. During this period of secretory inhibition, labeled collagen precursors were present within a variety of dense bodies, primarily located in a juxtanuclear location replacing the normal Golgi complex. The time course of3H‐proline labeling from 2 to 8 hours suggested that small, newly formed dense bodies fused to form larger dense bodies and pleomorphic structures (zebra bodies), within which collagen precursors appeared to undergo partial polymerization. Autophagosomes, many labeled with3H‐proline, also increased in number after colchicine administration. A gradual decline in3H‐proline label occurred from 4 to 24 hours, presumably due to exocytosis of dense bodies or by the digestion of labeled collagen precursors within autophagosomes.These results support the concept that an intact microtubular network is essential for the organized transport of collagen precursors, from the rough endoplasmic reticulum to the Golgi apparatus, and the eventual transport and exocytosis of collagen secretory g

ISSN:0003-276X    

DOI:10.1002/ar.1092010403

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

年代:1981

数据来源: WILEY

摘要:

AbstractCultivated mouse melanocytes with the genotype ofD/‐ andd/dobtained from dorsal skin of infants, and the variant melanoma cells (sublineagm) in which melanosomes were aggregated around the nucleus were characterized by means of electron microscopy. InD/‐ melanocytes, dendrites contained a number of microtubules and 10‐nm filaments, mitochondria, endoplasmic reticulum, and peripherally distributed melanosomes. On the other hand, ind/dmelanocytes andagmcells, melanosomes were aggregated in the perinuclear region of the cell body. Their fibrous dendrites contained numerous microtubules and 10‐nm filaments, mitochondria, and endoplasmic reticulm. It is suggested that the interactive process of melanosomes with cytoskeletal elements is defective ind/dmelanocytes, and that a similar defect is present ina

ISSN:0003-276X    

DOI:10.1002/ar.1092010404

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

年代:1981

数据来源: WILEY

摘要:

AbstractAt the early steps 3–7 of spermiogenesis the hemispherical Golgi apparatus elaborates and is closely associated to the acrosomic system which grows at the surface of the spermatid's nucleus. It shows two distinct zones, a cortex made up of flattened saccules and related membranous tubules, and a medulla containing various types of vesicular profiles. The various components of the cortex of the Golgi apparatus were tested for their reactivity to three phosphatases. Nicotinamide adenine dinuclèotide phosphatase activity (NADPase, Smith, 1980) was observed in the middle two to six saccules in the stack with a midsaccule being more reactive than the saccules above and below. A weak and spotty reaction was also noted in the remaining saccules on the trans‐face of the stack and in the thick elements making up the GERL on the trans aspect of the stacks of saccules. Thiamine pyrophosphatase activity (TPPase, Novikoff and Goldfisher, 1961) was found in one or two saccules on the trans‐face of the stacks but was absent from the other Golgi components. Cytidine monophosphatase activity (CMPase, Novikoff, 1967) was observed in the GERL, in vesicles of the medulla and in the developing acrosomic system. In the intersaccular regions of the cortex the branching membranous tubules showed the same reactivity for the phosphatases to that of the saccules to which they are connected. ER cisternae associated with the Golgi apparatus, anastomotic membranous tubules seen in the peripheral Golgi region, small vesicles, as well as the first saccule on the cis‐face of the stacks were all negative for the three enzymes studied. These data indicated that in the cortex of the Golgi apparatus there were several distinct compartments that could be distinguished on the basis of structural and cytochemical

ISSN:0003-276X    

DOI:10.1002/ar.1092010405

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn the epididymis of the guinea pig, zone II exhibits striking histological features that distinguish it readily from the other six regions of the epididymis. At the light microscope level, the pseudostratified epithelium of zone II is characterized by tall principal cells that are densely packed with large, intensely staining granules or droplets ranging up to 8μ in diameter. At the electron microscope level, the principal cells exhibit numerous large lipid droplets and abundant agranular endoplasmic reticulum, which is frequently arranged in concentric whorls around one or more of the droplets. Quantitative biochemical studies comparing zone II with zones I and III show that zone II contains 2.5–3‐fold more cholesterol and a significantly greater amount of cholesterol ester than the other two zones. These data indicate that the epididymal duct of the guinea pig includes a clearly defined region of epithelial cells possessing ultrastructural and biochemical characteristics consistent with steroidogenic activity. The potential significance of these observations to the epididymal physiology of the guinea pig and epididymal physiology in general is discu

ISSN:0003-276X    

DOI:10.1002/ar.1092010406

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe development of the lung in 25 human embryos and early fetuses up to 140 mm crown–rump length was studied by examination of serial histologic sections, morphometry, and selected reconstructions. The proportion of pulmonary tissue consisting of tracheobronchial tree increases during this period. Bronchial cross‐sectional diameter, length of the most distal bronchial branches, and thickness of the distal mesenchyme decline during development. The results are consistent with the concept that the dichotomous branching of the growing tracheobronchial tree occurs because of resistance to forward growth of the bronchial branch by compressed mesenchyme, pleura, or adjacent structures. Division and further growth of the bronchus takes place in areas of lower resistance. This process produces a “filling in” of space available for lung development and brings the epithelial and mesenchymal elements into their definitive relati

ISSN:0003-276X    

DOI:10.1002/ar.1092010407

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe fine morphology of glomeruli present in the mesonephroi of mouse embryos from days 12 to 14 of gestational age is described. The glomeruli are rudimentary, ephemeral structures which probably result from temporary juxtaposition of a blood capillary to the ventral extremity of a mesonephric tubule. Yet, they might possess a certain degree of functionality.

ISSN:0003-276X    

DOI:10.1002/ar.1092010408

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

年代:1981

数据来源: WILEY

摘要:

AbstractRats were sympathetically denervated on one side by avulsion of the superior cervical ganglion either immediately after birth (within 4 hr) or when the salivary glands were fully developed. Nine weeks after ganglionectomy the parotid glands were subjected to microscopical studies. As shown by the lack of specific fluorescence, sympathetic denervation caused an almost total depletion of catecholamines in the acini. This was further substantiated at the electron microscopic level using KMnO4as fixative. No alterations in either gland weight or in acinar cell size were noticeable after adult sympathectomy. On the other hand, neonatal denervation caused a decrease in gland weight as well as acinar cell hypotrophy. The mean volume of individual acinar cells was reduced by roughly 25% and the granule volume density by about 50%. Also the mean volume of individual granules was decreased. These findings indicate an important role for the sympathetic nerve system in the maturation of the rat parotid gland.

ISSN:0003-276X    

DOI:10.1002/ar.1092010409

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

年代:1981

数据来源: WILEY

摘要:

AbstractIn the sheep, fetal lung development proceeds to a later stage of maturity than in smaller laboratory animals. Of the four stages in pulmonary development recognizable in this species–embryologic, pseudoglandular, canalicular, and aveolar–the latter three are described in the present study using histologic, morphometric, and ultrastructural techniques. During the pseudoglandular stage, the major airways developed centrifugally. Cartilaginous, glandular, muscular, vascular, and neural elements were present in major airway walls from an early age. During the canalicular stage, volume expansion of the lung was accomplished by rapid growth of large terminal spaces. In the final stage, alveoli were formed following subdivision of the large terminal spaces by alveolar crests. The alveolar lining epithelium differentiated during the latter two stages producing a large increase in alveolar surface area, particularly during the alveolar stage; a large increase in pulmonary capillary surface area also accompanied alveolar development. Thus, just prior to birth, the fetal sheep lung has a well‐developed airway system and alveolar network, in preparation for postnatal gas exc

ISSN:0003-276X    

DOI:10.1002/ar.1092010410

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

年代:1981

数据来源: WILEY

摘要:

AbstractThe fiber connections between the trigeminal mesencephalic nucleus and tract and the trochlear nerve root of 15 cats were examined after silver impregnation of the pontomescencephalic region of the brains. The results revealed that: (a) some of the mesencephalic root fascicles join the trochlear root, (b) some of the mesencephalic root cells contribute their processes to the trochlear root, and (c) some mesencephalic cells are found amidst the fibers of the trochlear nerve during its intrabulbar course. The fibers of the trochlear nerve were counted at certain preselected sites before and after crossing the mesencephalic nucleus. The statistical data obtained indicated that the trigeminal mesencephalic root contributes 4–10% of the fibers of the trochlear nerve, before it crosses the mesencephalic nucleu

ISSN:0003-276X    

DOI:10.1002/ar.1092010411

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

年代:1981

数据来源: WILEY