摘要:

AbstractThe fine structure of hepatocytes from rats maintained on a controlled feeding schedule are described. Liver samples were processed for electron microscopy, histochemistry and chemical determinations of glycogen at precise time‐intervals following a 30‐hour fast and a 2‐hour meal. Hepatocytes from 30‐hour‐fasted rats with extremely low hepatic glycogen levels were devoid of glycogen particles. Centrilobular cells showed areas of the cytoplasm rich in vesicles of smooth endoplasmic reticulum (SER) while periportal hepatocytes contained less extensive regions of SER. Soon after feeding the fasted rats, glycogen particles appeared in regions of the cell rich in SER. Centrilobular hepatocytes contained numerous glycogen areas which were infiltrated with tubules of SER, while periportal cells showed dense glycogen deposits with SER restricted to the periphery of the masses of glycogen. Throughout glycogen deposition each glycogen particle was closely associated with membranes of SER until maximum glycogen deposition was achieved 12 hours after initiation of feeding. At this point SER was reduced to the lowest amounts of the time‐periods studied. During stages of glycogen depletion SER proliferated and reached the highest concentration measured in this study. Tubules of SER were present throughout the glycogen masses of centrilobular hepatocytes, whereas in periportal cells the organelle was restricted to the periphery of the glycogen masses. It is concluded that SER is associated with glycogen particles in rat hepatocytes during both deposition and depletion

ISSN:0002-9106    

DOI:10.1002/aja.1001430402

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

年代:1975

数据来源: WILEY

摘要:

AbstractSpinal cords of 15 species representing six classes of vertebrates and the protochordate amphioxus were examined with histochemical methods for esterase, ATPase, LDH, PAS, and PAS‐phosphorylase. Ependymal and glial cell processes were demonstrated and resembled heavy metal impregnations. Capillaries also were shown. The prominence of glycogen‐rich ependymal structures in the spinal cord of nonmammalian vertebrates, and the increase in intramedullary blood vessels in placental mammals, suggest an inverse relationship between the relative development of the ependyma and of the blood supply. The marsupial opossum has sparseness of both ependyma and capillaries, but exhibits an extensive pattern of branched glial processes in both white and gray mat

ISSN:0002-9106    

DOI:10.1002/aja.1001430403

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

年代:1975

数据来源: WILEY

摘要:

AbstractHistophysiological examinations of the bovine and monkey pineal gland indicate that this organ may be involved in the secretion of polypeptides. Using various histochemical procedures designed to identify peptidesecreting cells, granules and/or droplets of presumptive secretory product were identified within cellular processes, within the walls of blood vessels and associated with multilayered corpuscles (corpora arenacea). In bovine pineal tissue, the stained material was found most often in what appeared to be pinealocyte processes, as perivascular granules and associated with multilayered corpuscles. In the monkey pineal the stainable material was more distinct; this was probably due to the earlier fixation of the glands after death of the animals. In this species, the presumptive secretory material was found in nerve fibers, occasionally in glial cell and pinealocyte processes and within and around the walls of capillaries. In nerve fibers, the stained material sometimes resembled Herring bodies of the posterior pituitary gland. Similar material appeared to be located in capillary endothelial cells and within multilayered corpuscles. In pineal tissue of both species, calcium was detectable histochemically within multilayered corpuscles. Although tinctorially different, the presumptive neurosecretory material was similar to that found in the posterior pituitary gland. As a working hypothesis, we propose that polypeptides may be released from cells in conjunction with a carrier protein and that the mechanism of secretion of the polypeptide into the vascular system may involve its exchange for calcium. The calcium is then theoretically deposited in the multilayered corpuscles.

ISSN:0002-9106    

DOI:10.1002/aja.1001430404

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

年代:1975

数据来源: WILEY

摘要:

AbstractThe pineal gland of the 13‐lined ground squirrel (Citellus tridecemlineatus) has been examined at the light and electron microscopic level. This gland is composed of low‐density parenchymal cells interspersed among which are occasional glial, vascular and neural elements. Punctuating the glandular parenchymal mass are prominent perivascular and intercellular spaces.The parenchymal cells possess numerous mitochondria and less prominent profiles of rough and smooth‐surfaced endoplasmic reticulum. Golgi apparatus, microtubules and lipid droplets of varying size and electron density constitute regular cytoplasmic features, with dense‐core vesicles being present occasionally. The parenchymal cells have numerous processes. One among these in each cell extends for several micra to terminate in a bulbous expansion containing both clear and dense‐core vesicles and occasional electron‐dense inclusions. These bulbous terminals are found within the perivascular and intercellular spaces where they course in close proximity to both other parenchymal elements and axon terminals. Glial cells and their processes invest the pineal periphery and incompletely separate the parenc

ISSN:0002-9106    

DOI:10.1002/aja.1001430405

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

年代:1975

数据来源: WILEY

摘要:

AbstractBrine shrimp (Artemia salina) were prepared for light and electron microscopy at several stages. Immersion‐fixed, rapid Golgi impregnations demonstrated two distinct neuronal types in thoracic appendages of mature, freely swimmingArtemia. Isolated motor neurons had large cell somas and thick, radiating dendrites at the body wall‐limb junction. A long, elaborate axon extended into the limb. Groups of a second type of neuron with smaller somas and very thin, radiating processes occurred in the distal limb near presumably tactile bristles. Thick axons from motor neurons were traced to terminals associated with limb muscle. Both muscle and axon were best seen with Nomarski optics. Motor axons possessed elongate, irregularly shapedboutons en passantand morphologically variableboutons terminaux; the latter included huge endings with knobbed projectiles arising from thick collaterals, or smaller, round boutons from thin collaterals. In addition, a thick, unidentified axon coursed longitudinally within the central body wall, sending short collaterals peripherally. The elaborate peripheral neurons described in this Golgi study may be anatomical correlates for the extraordinary coordination of mature brine shrimp. BecauseArtemiamovements resemble those of leech and decapods, which have been studied extensively electrophysiologically, the possibility of similarly elaborate peripheral structures supplementing central control of locomotion in those invertebrates should be conside

ISSN:0002-9106    

DOI:10.1002/aja.1001430406

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

年代:1975

数据来源: WILEY

摘要:

AbstractSubmandibular and major sublingual salivary glands of the opossum contain histochemically demonstrable neutral mucosubstances, nonsulfated acid mucosubstances and sulfomucins. Sialomucins could not be demonstrated conclusively with the methods used in this study. Special serous cells of the opossum submandibular gland contained low concentrations of acidic mucosubstances but no appreciable concentration of neutral mucosubstances was seen. Sulfomucins were not observed in special serous cells. The mucous tubules of the submandibular gland contained high concentrations of neutral mucosubstances. No appreciable acidic mucosubstance was demonstrated in the submandibular gland mucous tubules. Unlike the mucous tubules of the submandibular gland, the major sublingual gland mucous tubules contained high concentrations of both neutral and acidic mucosubstances. The mucous tubules often contained sulfomucin‐positive cells interspersed among cells that contained high concentrations of non‐sulfated acidic mucosubstance. Marked staining of sulfated acidic mucosubstance was seen only in the major sublingual gland, in both the mucous tubules and in the seromucous demilunes. The seromucous demilunes contained both sulfated and non‐sulfated acidic mucosubst

ISSN:0002-9106    

DOI:10.1002/aja.1001430407

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

年代:1975

数据来源: WILEY

ISSN:0002-9106    

DOI:10.1002/aja.1001430401

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

年代:1975

数据来源: WILEY