scholarly journals Contribution of Reductase Activity to Quinone Toxicity in Three Kinds of Hepatic Cells

2012 ◽  
Vol 35 (4) ◽  
pp. 634-638 ◽  
Author(s):  
Yasuhiro Ishihara ◽  
Kaori Tsuji ◽  
Satomi Ishii ◽  
Kyoko Kashiwagi ◽  
Norio Shimamoto
Keyword(s):  
Reductase Activity ◽  
Hepatic Cells ◽  
Quinone Toxicity

scholarly journals LIVER MICROSOMES

1956 ◽  
Vol 2 (2) ◽  
pp. 171-200 ◽  
Author(s):  
G. E. Palade ◽  
P. Siekevitz
Keyword(s):  
Cytochrome C ◽  
Reductase Activity ◽  
Liver Microsomes ◽  
Minor Component ◽  
Aging Treatment ◽  
Homogeneous Material ◽  
Cytochrome C Reductase ◽  
Hepatic Cells ◽  
A Minor ◽  
Endoplasmic Reticula

Rat liver, liver homogenates, and microsome fractions separated therefrom were examined systematically in the electron microscope in sections of OsO4-fixed, methacrylate-embedded tissue and pellets. It was found that most microsomes are morphologically identical with the rough surfaced elements of the endoplasmic reticula of hepatic cells. They appear as isolated, membrane-bound vesicles, tubules, and cisternae which contain an apparently homogeneous material of noticeable density, and bear small, dense particles (100 to 150 A) attached to their outer aspect. In solutions of various osmolar concentrations they behave like osmometers. The findings suggest that they derive from the endoplasmic reticulum by a generalized pinching-off process rather than by mechanical fragmentation. The microsome fractions contain in addition relatively few vesicles free of attached particles, probably derived from the smooth surfaced parts of the endoplasmic reticula. Dense, peribiliary bodies represent a minor component of the same fractions. The microsomes derived from 1 gm. wet weight liver pulp contained (averages of 10 experiments) 3.09 mg. protein N, 3.46 mg. RNA (RNA/protein N = 1.12), and 487 µg. phospholipide P. They displayed DPNH-cytochrome c reductase activity and contained an alcohol-soluble hemochromogen. The microsome preparations proved resistant to washing and "aging." Treatment with versene and incubation with ribonuclease (30 minutes at 37°C.) resulted in appreciable losses of RNA and in partial or total disappearance of attached particles. Treatment with deoxycholate (0.3 to 0.5 per cent, pH = 7.5) induced a partial clarification of the microsome suspensions which, upon centrifugation, yielded a small pellet of conglomerated small, dense particles (100 to 150 A) with only occasionally interspersed vesicles. The pellet contained ∼80 to 90 per cent of the RNA and ∼20 per cent of the protein N of the original microsomes. The supernatant accounted satisfactorily for the materials lost during deoxycholate treatment. The findings suggest that the microsomal RNA is associated with the small particles whereas most of the protein and nearly all of the phospholipide, hemochromogen, and DPNH-cytochrome c reductase activity are associated with the membrane or content of the microsomes.

Hepatic Ultrastructure Changes Induced by Lithocholic Acid

1967 ◽  
Vol 25 ◽  
pp. 162-163 ◽  
Author(s):  
F. G. Zaki
Keyword(s):  
Endoplasmic Reticulum ◽  
Lithocholic Acid ◽  
Smooth Endoplasmic Reticulum ◽  
Protein Diet ◽  
Low Protein Diet ◽  
Electron Microscopic ◽  
Hydropic Degeneration ◽  
Hepatic Cells ◽  
Low Protein ◽  
Microscopic Studies

Addition of lithocholic acid (LCA), a naturally occurring bile acid in mammals, to a low protein diet fed to rats induced marked inflammatory reaction in the hepatic cells followed by hydropic degeneration and ductular cell proliferation. These changes were accompanied by dilatation and hyperplasia of the common bile duct and formation of “gallstones”. All these changes were reversible when LCA was withdrawn from the low protein diet except for the hardened gallstones which persisted.Electron microscopic studies revealed marked alterations in the hepatic cells. Early changes included disorganization, fragmentation of the rough endoplasmic reticulum and detachment of its ribosomes. Free ribosomes, either singly or arranged in small clusters were frequently seen in most of the hepatic cells. Vesiculation of the smooth endoplasmic reticulum was often encountered as early as one week after the administration of LCA (Fig. 1).

Discovery of intracellular 2,8 dihydroxyadenine crystals in bovine lymphatic and hepatic cells

1987 ◽  
Vol 45 ◽  
pp. 906-907
Author(s):  
W. E. Rigsby ◽  
D. M. Hinton ◽  
V. J. Hurst ◽  
P. C. McCaskey
Keyword(s):  
Polarized Light ◽  
Paraffin Sections ◽  
Tissue Samples ◽  
Whole Cells ◽  
Tissue Sections ◽  
Hepatic Cells ◽  
Slaughter House ◽  
Mammalian Tissues ◽  
Carbon Coated ◽  
Cellular Components

Crystalline intracellular inclusions are rarely seen in mammalian tissues and are often difficult to positively identify. Lymph node and liver tissue samples were obtained from two cows which had been rejected at the slaughter house due to the abnormal appearance of these organs in the animals. The samples were fixed in formaldehyde and some of the fixed material was embedded in paraffin. Examination of the paraffin sections with polarized light microscopy revealed the presence of numerous crystals in both hepatic and lymph tissue sections. Tissue sections were then deparaffinized in xylene, mounted, carbon coated, and examined in a Phillips 505T SEM equipped with a Tracor Northern X-ray Energy Dispersive Spectroscopy (EDS) system. Crystals were obscured by cellular components and membranes so that EDS spectra were only obtainable from whole cells. Tissue samples which had been fixed but not paraffin-embedded were dehydrated, embedded in Spurrs plastic, and sectioned.

Lamin B receptor: role on chromatin structure, cellular senescence and possibly aging

2020 ◽  
Vol 477 (14) ◽  
pp. 2715-2720
Author(s):  
Susana Castro-Obregón
Keyword(s):  
Cellular Senescence ◽  
Nuclear Membrane ◽  
Chromatin Structure ◽  
Cholesterol Synthesis ◽  
Reductase Activity ◽  
Chimeric Protein ◽  
Nuclear Lamina ◽  
Lamin B ◽  
Inner Nuclear Membrane ◽  
Lamin B Receptor

The nuclear envelope is composed by an outer nuclear membrane and an inner nuclear membrane, which is underlain by the nuclear lamina that provides the nucleus with mechanical strength for maintaining structure and regulates chromatin organization for modulating gene expression and silencing. A layer of heterochromatin is beneath the nuclear lamina, attached by inner nuclear membrane integral proteins such as Lamin B receptor (LBR). LBR is a chimeric protein, having also a sterol reductase activity with which it contributes to cholesterol synthesis. Lukasova et al. showed that when DNA is damaged by ɣ-radiation in cancer cells, LBR is lost causing chromatin structure changes and promoting cellular senescence. Cellular senescence is characterized by terminal cell cycle arrest and the expression and secretion of various growth factors, cytokines, metalloproteinases, etc., collectively known as senescence-associated secretory phenotype (SASP) that cause chronic inflammation and tumor progression when they persist in the tissue. Therefore, it is fundamental to understand the molecular basis for senescence establishment, maintenance and the regulation of SASP. The work of Lukasova et al. contributed to our understanding of cellular senescence establishment and provided the basis that lead to the further discovery that chromatin changes caused by LBR reduction induce an up-regulated expression of SASP factors. LBR dysfunction has relevance in several diseases and possibly in physiological aging. The potential bifunctional role of LBR on cellular senescence establishment, namely its role in chromatin structure together with its enzymatic activity contributing to cholesterol synthesis, provide a new target to develop potential anti-aging therapies.

Persistence of HCV in quiescent hepatic cells under conditions of an interferon-induced antiviral response

2013 ◽  
Vol 51 (01) ◽  
Author(s):  
O Bauhofer ◽  
A Ruggieri ◽  
B Schmid ◽  
P Schirmacher ◽  
R Bartenschlager
Keyword(s):  
Antiviral Response ◽  
Hepatic Cells

Visceral fat drives 5[alpha]-reductase activity independent of BMI in women with polycystic ovarian syndrome

2015 ◽  
Author(s):  
Punith Kempegowda ◽  
Michael W O'Reilly ◽  
Nicola J Crabtree ◽  
Angela E Taylor ◽  
Beverly A Hughes ◽  
...  
Keyword(s):  
Visceral Fat ◽  
Polycystic Ovarian Syndrome ◽  
Reductase Activity ◽  
Ovarian Syndrome
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