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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An intradermal nevus, in which a number of nevic corpuscles were clearly observed, was studied, using the electron microscope. Nevic corpuscles contained laminated cells consisting of flattened cytoplasmic processes stretching across the corpuscles to form a complicated labyrinth. The perikaryon of these cells contained premelonosome-like dense bodies and other organelles including mitochondria, rough-surfaced endoplasmic reticulum, free ribosomes, and Golgi apparatus. Neither axons nor dendrites were found in these areas. From these observations, it was concluded that the nevic corpuscles were composed exclusively of nevus cells and could be clearly distinguished from Meissner corpuscles. This view would support the idea of a unitary origin of nevus cells. In addition, an isolated cilium found in a laminated cell is briefly discribed.
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PMID:Electron microscopic study of nevic corpuscle. 5 57

The fine structure of the outer capsule of the snout muscle spindles of the Japanese lesser shrew-mole (42 spindles from 9 animals) was described electron microscopically. The capsule of the snout muscle spindle is composed of 5 to 6 layers of the so-called capsule cells derived from the perineural epithelium of the peripheral nerve which supplies the spindle. The capsule cells revealed the presence of numerous pinocytotic vesicles, granular endoplasmic reticulum, abundant ribosomes, mitochondria, dense bodies, microvesicles and Golgi complex. It would be highly suggestive of their secretory or transporting activity. The various types of plication within the capsule of the muscle spindle were detected in the equatorial region. By means of such projections the functioning surface of the outer capsule has been enormously increased.
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PMID:The fine structure of the outer capsule of the snout muscle spindle in the Japanese lesser shrew-mole. 13 18

The different categories of cells described by many authors in the pineal gland of mammals have been critically considered. In some mammalian species, two different populations of pinealocytes have been observed. To each of these populations a specific secretory process can be attributed. One is characterized by the formation of granular vesicles originating from the Golgi apparatus, the other by the formation of material directly from the cisterns of the granular endoplasmic reticulum. Both of these secretory processes appear to be also present in the pineal of the mole, the hedgehog, and the rat, mammals in which generally only one population of pinealocytes has been described. The physiological consequences of these findings have been discussed.
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PMID:On the presence of different populations of pinealocytes in the mammalian pineal gland. 32 26

The regio olfactoria of the mole, Talpa europaea, was studied by scanning and transmission electron microscopy. Peculiar structural differentiations, i.e. ovoid-shaped, balloon-like protuberances were found on the surface of the supporting cells. The apical portion of these protuberances contained finely dispersed granular material, whereas in their central part vesicular extensions of the smooth endoplasmic reticulum were observed.
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PMID:Apical protuberances of supporting cells in the regio olfactoria of the mole, Talpa europaea, Linnaeus, 1758 (Insectivora, Talpidae). 71 12

The effect of a proteolytic enzyme, pronase, on material present in cisternae of the granular endoplasmic reticulum of mole pinealocytes demonstrates their proteinaceous nature.
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PMID:The pineal gland of the mole (talpa europaea L.). IV. Effect of pronase on material present in cisternae of the granular endoplasmic reticulum of pinealocytes. 90 4

The ultrastructure of pinealocytes of the mole-rat (Spalax ehrenbergi), a blind subterranean mammal living in complete darkness, was examined and compared with pinealocytes of other mammals. Two different populations of pinealocytes (I and II) were observed. They differed in general aspect. In location and especially in their content of cell organelles involved in synthetic processes. Mitochondria, ribosomes, granular endoplasmic reticulum, lysosomes, lipid inclusions and glycogen granules were present in the perikarya of pinealocytes of both populations. In the pinealocyte of population I some granular vesicles were occasionally observed in the cell body. Their presumed origin from the Golgi apparatus could not be clearly demonstrated. In the perikaryon of this pinealocyte, concentrations of ribosomes and of cisternae of the granular endoplasmic reticulum were constantly observed. These concentrations may indicate an intensive synthetic activity. Pinealocytes of population II were characterized by accumulations of proteinaceous material in some cisternae of the granular endoplasmic reticulum and between the two layers of the nuclear membrane. The origin of these peculiar elements is discussed.
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PMID:The pineal gland of the mole-rat (Spalax ehrenbergi, Nehring). I. The fine structure of pinealocytes. 99 Dec 56

The mole has a single pair of accessory sex organs with features of both the prostate and the seminal vesicle, for which the term prostate gland is not appropriate. Seasonal changes occuring in this gland were related to four periods: a) the quiescence period, b) the maturation period, c) the active period and d) the involution period. During the quiescence period the cuboidal epithelial cells display a quasi-embryonic fine structure and are sparse in cytoplasmic organelles, but rich in glycogen and lipopigment. With the onset of sexual activity glycogen and lipopigment disappear and the rough endoplasmic reticulum as well as the Golgi apparatus begin to proliferate. The fully active gland is lined by a low epithelium with parallel stacks of rough endoplasmic reticulum, a large Golgi apparatus and several lysosomes and secretory granules. In the involution period the gland collapses and the epithelial cells are eliminated by hetero- and autophagic processes. During this period a great number of presumably endocrine cells were observed. The results were compared with findings in experimental studies and those on postnatal development of accessory sex glands in laboratory animals.
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PMID:Seasonal changes in the fine structure of the accessory sex gland in the mole (Talpa europaea). 100 Jun 10

A significant amount of biliary cholesterol is carried in unilamellar-phospholipid (lecithin) vesicles, in both supersaturated human hepatic bile and unsaturated rat bile. This fact supports the concept that biliary cholesterol is normally secreted in phospholipid vesicles from the hepatocyte into the canaliculus. The fundamental aspects of biliary lipid secretion relate first to the quantitative determinants of hepatocytic cholesterol secretion into the bile and, second, to the cell biology of this process. There is a tight curvilinear coupling between the rates of bile acids and biliary lipid secretion in all animal species. The hydrophobicity of the bile acid pool may modify this cosecretory mechanism in that more hydrophobic bile acids recruit more phospholipid and cholesterol per mole of bile acid secreted into the bile. The quantitative significance of this effect, however, is relatively minor. In contrast, intrahepatic determinants, such as the rates of hepatic cholesterol esterification and very low density lipoprotein production modulated by dietary factors, may markedly change the amount of cholesterol carried in vesicles into the bile. Recent studies provide strong evidence to support the concept that biliary cholesterol output is also modulated by the amount of free cholesterol available in specific regions of the endoplasmic reticulum for recruitment by the bile acid cosecretory mechanism. The origin of biliary lipids is in the smooth endoplasmic reticulum membranes. The intracellular transport and the canalicular secretory mechanism of the precursor of biliary lipid vesicles is mostly unknown. Two theories related to the cell biology of biliary lipid secretion are discussed in this article, the fusion-budding model and the exocytotic model.
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PMID:Secretion of biliary lipids from the hepatocyte. 221 Jun 41

We studied by light and electron microscopy the diffuse iris nevus of an eye in a 16-year-old patient with oculodermal melanocytosis and choroidal malignant melanoma. The nevus cells in the anterior border layer of the iris appeared to be poorly differentiated, showing moderate infolding of the nuclear membrane with heterochromatin clumping, watery cytoplasm, abundant mitochondria, fine filaments, rough endoplasmic reticulum, and numerous pinocytotic vesicles. Small scattered immature melanosomes and occasional giant melanosomes were observed in these cells. Deep in the iris stroma, however, nevus cells were found singly or in small groups, and were associated with an increasing number of melanized melanosomes and cytoplasmic filaments and reduced numbers of other cytoplasmic organelles, such as mitochondria and free ribosomes. Differentiation of the iris nevus cells appeared to progress from the anterior border layer toward the iris stroma. This observation suggests that intrastromal nevi may be more benign than nevi with surface plaque. The ultrastructural characteristics of the diffuse nevi of oculodermal melanocytosis were compared with those of other iris nevi.
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PMID:Diffuse iris nevus in oculodermal melanocytosis: a light and electron microscopic study. 279 14

Protein disulfide-isomerase, a protein localized to the lumen of the endoplasmic reticulum of eukaryotic cells, catalyzes the posttranslational formation and rearrangement of protein disulfide bonds. As isolated from bovine liver, the enzyme contains 0.8 free sulfhydryl group per mole of protein monomer and 3.1 disulfide bonds. Single-turnover experiments in which the disulfide bonds of the native enzyme are reduced by glutathione reveal three distinct reduction steps corresponding to the sequential reduction of the three disulfide bonds. The fastest disulfide to be reduced undergoes a change in the rate-determining step with increasing GSH concentration from a step which is second-order with respect to GSH concentration to a step which is first-order in GSH concentration. The disulfide which is reduced at an intermediate rate displays kinetics that are first-order in GSH concentration, and the slowest disulfide to be reduced exhibits kinetics which are second-order in GSH concentration. The enzyme catalyzes the steady-state reduction of a disulfide-containing hexapeptide (CYIQNC) by GSH. Initial velocity kinetic experiments are consistent with a sequential addition of the substrates to the enzyme. Saturation behavior is not observed at high levels of both substrates (Km for GSH much greater than 14 mM, Km for CYIQNC much greater than 1 mM). Only one of the three disulfides appears to be kinetically competent in the steady-state reduction of CYIQNC by GSH. The second-order thiol/disulfide exchange reactions catalyzed by the enzyme are 400-6000-fold faster than the corresponding uncatalyzed reactions.
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PMID:Catalysis of thiol/disulfide exchange: single-turnover reduction of protein disulfide-isomerase by glutathione and catalysis of peptide disulfide reduction. 281 70


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