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doi: 10.1002/aja.1001590302pmid: 7010981
“Electromyography: Dynamic Gross Anatomy” is the first in a series of invited review articles by leaders in fields of current interest.
doi: 10.1002/aja.1001590303pmid: 7211709
Structural development of the neural lobe of the hypophysis was studied by light and electron microscopy in five human fetuses ranging from 7.5 to 19 weeks of ovulation age.
Atwal, Onkar S.; Brown, Laurie M.
doi: 10.1002/aja.1001590304pmid: 7211710
An ultramicroscopic analysis of caprine lung glycoproteins, designed to detect plasmalemma‐associated sulfoglycoprotein of alveolar type I and alveolar type II cells, was performed. High‐iron diamine staining demonstrated a layer containing sulfated glycoproteins at the apical plasmamembrane of alveolar type I cells and microvilli of alveolar type II cells. The cytoplasmic vesicles of the alveolar type I cell contained the reaction product on the inner leaflet of the vesicular unit membrane. The vesicles showed a variety of interactions with the apical plasma membrane. High‐iron diamine staining also demonstrated sulfogly‐coproteins in the cytoplasmic granules of the mast cells in the alveolar septum. The present study gives evidence that plasmalemma of the alveolar cells of the goat lung possesses exposed hyaluronic acid groups.
Wathes, D. Claire; Wooding, F. B. P.
doi: 10.1002/aja.1001590305pmid: 7211711
The paper describes the changes occuring in the uterine and chorionic epithelia of the cow between days 18 and 28 of gestation, before and during implantation. The irregular uterine epithelium of the non‐pregnant cow was simplified to a tall columnar epithelium before attachment began. Areas of attachment were first observed at day 20 in the region of the embryo. Such sites were characterized by the presence of pale uterine cells containing up to 8 nuclei (“giant cells”) which accounted for nearly 50% of the epithelial area by day 24. Fetal binucleate cells were found in contact with, and partly across, the microvillar junction at all stages examined, and the presence of granules characteristic of binucleate cells within the giant cells suggested that the fetal cells contributed to their formation. Many uterine epithelial cells underwent degenerative changes between 22 and 28 days, and residues equivalent to their pyknotic remnants were found at the microvillar junction and within the mononucleate chorion cells. By day 28 some of the giant cells appeared to be degenerating, and areas of low cuboidal epithelium were present. This epithelium resembled the type found in the mature placenta. There was evidence that binucleate cell migration continued at this time. Nevertheless, the definitive membrane in the mature bovine placenta is epitheliochorial.
Sato, Akira; Spicer, Samuel S.
doi: 10.1002/aja.1001590306pmid: 7211712
Ultrastructural and complex‐carbohydrate cytochemical studies were carried out on guinea pig gastric mucosa to assess the histochemical properties of the secretions of different gastric epithelial cells and to investigate the differentiation, origin, and renewal of certain cell types. The observations disclosed heterogeneity or variability of the secretory granules within individual mucigenic cells and zymogen cells. The cytochemical methods also served in characterizing and distinguishing five cell types in the gastric glands, including the isthmus cell, a mucous cell considered comparable to the mucous neck cell, the chief cell, and forms transitional between the isthmus and mucous cells and the mucous and zymogenic cells. The several cell types differed widely in the cytochemical properties of the secretory granules and the apical plasmalemma, and each had a distinctive distribution in the gastric gland. Cytochemical staining observed here provided evidence on synthesis and intracellular metamorphosis of mucous droplets and on formation of glycocalyx.
Grier, H. J.; Linton, J. R.; Leatherland, J. F.; De Vlaming, V. L.
doi: 10.1002/aja.1001590307pmid: 7211713
Testicular structure in Salmoniformes, Perciformes, Cypriniformes, and Atheriniformes has been examined and reinterpreted on the basis of two different tubular types, distinguished from each other by the intratubular distribution of spermatogonia. In the salmoniform, perciform, and cypriniform teleosts studied, spermatogonia are distributed along the entire length of the testicular tubules. However, in the atheriniform teleosts spermatogonia are restricted to the distal end of the tubule. Sperm development in teleosts is cystic, cysts being comprised of Sertoli‐cell processes. In both testicular types described, Sertoli cells phagocytize spermatid residual bodies. Together witb the germ cells, they comprise the only intratubular cell types within the teleostean testis.
Nunez, Eladio A.; Gershon, Perry; Gershon, Michael D.
doi: 10.1002/aja.1001590308pmid: 6452051
The serotonin concentration in the bat pancreas was determined at nine times during the year. Pancreatic ultrastructure was also examined. The pancreatic level of serotonin was uniform throughout the year except in late May, when it fell dramatically from a normal level of 3.14 ±.19 μgm/gm to 0.40 ± .05 μgm/gm. No seasonal changes in islet fine structure were found; however, the ultrastructure of exocrine cells was seen to be changed radically only in bats captured in late May. At this time, bats develop unusual cytoplasmic structures in the exocrine cells. These structures consist of membrane‐limited bodies containing long, straight, and parallel paracrystalline arrays of stacked membranes and round or pleomorphic osmiophilic granules. Depletion of serotonin with reserpine or parachlorophenylalanine, or incubation of pancreatic tissue with different concentrations of serotonin, failed to provoke the formation of these structures in exocrine cells of active bats. Administration of 3H‐5‐hydroxytryptophan to bats, or incubation of bat pancreas with 3H‐serotonin, failed to demonstrate a labeling of pancreatic exocrine cells. Incubation of the gland with 3H‐serotonin, however, led to intense labeling of a subset of pancreatic terminal axons. It is concluded that the natural fall in the concentration of serotonin in late May is not the cause of the formation of the paracrystalline structures in pancreatic exocrine cells. The specific pancreatic uptake mechanism for serotonin found by Kovary et al. ('80) is probably a property of pancreatic neurites; these neurites might be serotonergic.
Koevary, Steven B.; McEvoy, Robert C.; Azmitia, Efrain C.
doi: 10.1002/aja.1001590309pmid: 6971051
Fragments of adult rat pancreas were incubated in vitro with tritiated serotonin at concentrations from 10−8 to 10−7 M. The pancreas exhibited an uptake of serotonin which was saturable, with an uptake constant (Km) of 8.75 × 10−7 M, and a Vmax of 873 pmoles per gram. Specificity was determined by the addition of fluoxetine or norepinephrine to the reaction mixture, both at 10−5 M. Fluoxetine significantly reduced the 3H‐5HT uptake, whereas norepinephrine was without effect. Metergoline (10−6 M), a specific 5‐HT postsynaptic receptor blocker, similarly had no effect on the serotonin uptake in the pancreas. Radioautography of the fragments following uptake of tritiated serotonin (5 × 10−8 M) revealed silver‐ grain aggregates dispersed along blood vessels in the interstitial spaces of the exocrine and endocrine pancreas, areas known to be traversed by nerve fibers. There were no silver‐ grain aggregates over the exocrine or islet parenchymal cells. These data support the hypothesis that the pancreas is innervated by serotonergic fibers. Further evidence for this hypothesis was provided by a preliminary study demonstrating the presence of tryptophan hydroxylase in pancreatic homogenates. These serotonergic fibers may be involved in the regulation of pancreatic secretion.
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