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At least 415 records · Page 23Linked to original sources

PubMed1978

Analytical subcellular fractionation of jejunal biopsy specimens: enzyme activities, organelle pathology and response to corticosteroids in patients with non-responsive coeliac disease.

1. Jejunal biopsies from five patients with non-responsive coeliac disease have been subjected to analytical subcellular fractionation and enzymic microassay in order to compare the organelle pathology of this group with untreated but glutensensitive patients. 2. Compared with the gluten-sensitive group these non-responsive patients showed marked reduction of the endoplasmic reticulum enzymes, normal activities of lysosomal enzymes and slightly less severely reduced brush border activities. 3. It is suggested that the present biochemical studies in combination with previous clinical reports and measurements of DNA and protein synthesis by cultured mucosal biopsies delineate non-responsive coeliac disease as a distinct entity. 4. The patients were treated with oral prednisolone (20 mg daily) for between 5 and 9 weeks and the properties of the jejunal biopsies restudied. 5. Although morphologically there was only a partial restoration of the villus architecture the enzymic alterations and organelle abnormalities returned essentially to normal values.

Adult↗

PubMed1983

Distribution of radioactive silver in the subcellular fractions of various tissues of the rat and its binding to low molecular weight proteins.

In view of the electron microscopic evidence that silver does not penetrate cellular barriers, the distribution of radioactive silver in rat blood and subcellular fractions of liver, kidneys, spleen, and forebrain was studied. It was found that 24 h after a single intraperitoneal injection high levels of radioactivity were reached which decreased at different rates in the various tissues studied. In plasma, liver, and kidneys there was an initial rapid loss of radioactivity which was followed by a slower rate of loss. In the blood, forebrain, and spleen the loss of radioactivity was linear and somewhat slower than in the other three tissues. The cytosols of the liver and kidneys contained 60% while those of the forebrain and spleen contained 30% of the total radioactivity found in the tissue homogenates. Gel filtration on Sephadex G-75 showed that all cytosols contained two peaks of radioactivity; a high molecular weight peak which eluted just after the void volume and a low molecular weight peak. The amount of radioactivity in both peaks was, however, much lower in the chromatographic peaks of the forebrain and spleen than that found in those of the liver and kidneys. Furthermore, the spleen had a comparatively very small low molecular weight radioactive peak. In vitro experiments with liver cytosol showed similar results to those found in vivo in that the high molecular weight radioactive peak could be removed by heat. It is concluded that silver does enter cells and that silver thionein exists in the cytosols of forebrain, spleen, kidney, and liver.

Animals↗

PubMed1993

Age-related changes in the ceramide composition of the major gangliosides present in rat brain subcellular fractions enriched in plasma membranes of neuronal and myelin origin.

Age-related changes of the ceramide composition of gangliosides were studied in the synaptosomal and myelin fractions from rat brain, carrying plasma membranes of neuronal and glial origin, respectively. The five major gangliosides (GM1, GD1a, GD1b, GT1b, and GQ1b) present in these fractions were separated and quantitated by normal-phase HPLC. Each ganglioside was then fractionated by reverse-phase HPLC into the molecular species carrying a single long-chain base (LCB). The largely preponderant LCBs in the synaptosomal and myelin fractions were the C18:1 and C20:1. The content of C20:1 LCB, generally low at 1 month, increased with age in all analyzed gangliosides and in all subcellular fractions and was greater in the "b series" than in the "a series" gangliosides. Remarkably, GM1 was the only ganglioside where the proportion of LCB 20:1 was higher in the synaptosomal fraction than in the myelin fraction. The fatty acid composition of the C18:1 or C20:1 LCB species of the different gangliosides in the synaptosomal and myelin fractions did not undergo appreciable changes with age. Stearic acid was largely predominant in all the gangliosides of the synaptosomal fraction, more in the C18:1 than in the C20:1 LCB species (80-90% vs. 60-70%). The gangliosides of the myelin fraction were characterized by a lower content of 18:0 and a much higher content of 16:0 and 18:1 fatty acids than those of the synaptosomal fraction. Thus, the ceramide composition is different in the gangliosides of neuronal and myelin origin and appears to be subjected to an age-related control.

Aging↗

PubMed1985

Effect of sodium valproate on subcellular fraction enzymes in rat liver.

Previous observations that valproic acid (VPA) causes hepatic damage prompted us to investigate the effect of large doses of the drug (0.6, 1.2 and 1.8 mmol/kg/day) on a number of liver enzymes located on different subcellular fractions. In mitochondria, glutamate dehydrogenase, aspartate aminotransferase and ornithine carbamoyltransferase were significantly increased (1.8 mmol/kg/day). In microsomes, gamma-glutamyltransferase activity increased significantly (1.8 mmol/kg) and cytochrome P-450 content decreased significantly (1.2 and 1.8 mmol/kg). In cytosol, both aspartate and alanine aminotransferase activities were increased at all dose levels. These results indicate that VPA induces dose-dependent changes in some liver enzyme activities.

Animals↗

PubMed1981

Levels and syntheses of cerebrosides and sulfatides in subcellular fractions of jimpy mutants.

During the period of brain development, the levels of nonhydroxy- and hydroxycerebrosides in the cytosol from brains of jimpy mutants were determined by high-performance liquid chromatography and compared to those in the rest of the particulates from the same brains as well as those in the littermate controls. The concentrations of cerebrosides in jimpy brain preparations were much lower than in controls at all ages. In another experiment, [U-14C]glucose was injected intraperitoneally into jimpy mutants and their littermate controls. The amounts of radioactivity incorporated into cerebrosides and sulfatides in brain cytosol, the microsome-rich fraction, and the rest of the heavier particles were determined. Although the total radioactivity incorporated into these lipids was much lower in jimpy, the specific activities were 2-3 times the control value in all subcellular fractions.

Animals↗

PubMed1988

The estrogen binding protein in human pancreas: concentrations in subcellular fractions of normal pancreatic tissue, in duodenal juice during pancreatic stimulation and in peripheral serum in normal and pathological conditions.

The steroid binding properties of the human pancreatic estrogen binding protein (hEBP) in cytosol were studied by equilibrium dialysis. A high ligand specificity of the protein was revealed. hEBP in cytosol binds unconjugated steroid estrogens with a medium affinity (Kd = 10(-7) M) but does not bind conjugated estrogens or unconjugated androgens, gestagens, glucocorticoids or cholesterol. Quantitation of hEBP by radioimmunoassay in subcellular fractions of human pancreatic tissue indicated that the protein is translocated into different subcellular compartments. Duodenal juice taken from patients following stimulation of pancreatic secretion by food ingestion (Lund's test) showed high hEBP concentrations, and the levels of hEBP changed concomitantly with the levels of pancreatic isoamylase, indicating that hEBP secretion was stimulated by food ingestion. The levels of hEBP in peripheral serum from healthy subjects showed no sex difference, but were positively correlated to age. Highly elevated (10-20-fold) hEBP levels were found in serum from patients with acute pancreatitis, while normal serum hEBP values were found in other abdominal diseases. It is speculated that hEBP might have a specific role in the transport of estrogens from the peripheral circulation via the pancreas to the duodenum. The elevated hEBP levels in patients with acute pancreatitis indicate that this protein may be used as a marker of cellular damage in the pancreas.

Carrier Proteins↗

PubMed2004

Oxidative stress and inhibition of oxidative phosphorylation induced by peroxynitrite and nitrite in rat brain subcellular fractions.

Nitrite and nitrate, two endogenous oxides of nitrogen, are toxic in vivo. Furthermore, the reaction of superoxide (produced by all aerobic cells) with nitric oxide (NO) generates peroxynitrite, a potent oxidizing agent, that can cause biological oxidative stress. Using subcellular fractions from rat brain hemispheres we studied oxidative stress induced by these nitrogen compounds with special emphasis on nitrite. The consumption of Vitamin C (ascorbate) and Vitamin E (alpha tocopherol), two of the important nutritional antioxidants, was followed in synaptosomes (nerve-ending particles) and mitochondria along with changes in parameters of mitochondrial oxidative phosphorylation. Nitrite, but not nitrate, oxidized ascorbate without oxidizing alpha tocopherol in both synaptosomes and mitochondria whereas peroxynitrite oxidized both ascorbate and alpha tocopherol. Functionally, both nitrite and peroxynitrite inhibited mitochondrial oxidative phosphorylation. Nitrite was less potent than peroxynitrite when the effects of equal concentrations of the two were compared. However, since nitrite is much more stable than peroxynitrite the impact of nitrite as an oxidant in vivo could be as much or even more significant than peroxynitrite. Nitrate would not have similar action unless it is reduced to nitrite. It is possible that nitrite may impair oxidative phosphorylation through modulating levels of nitric oxide, changing the activity of heme proteins or a mild uncoupling of mitochondria.

Animals↗

PubMed1983

Stimulation-dependent uptake of an extracellular marker to subcellular fractions of isolated neurohypophysial tissue.

Slices of ox neurohypophyses and groups of isolated rat neurointermediate lobes were incubated in a medium containing horseradish peroxidase (HRP) and stimulated by high K+ concentrations in the medium. After washing, the tissue was homogenized and subjected to subcellular fractionation in a Percoll/sucrose gradient. HRP was exclusively taken up by particles banding at a low density of the gradient. The HRP containing particles located to this region included vacuoles of a size comparable to secretory vesicles.

Animals↗

PubMed1985

The association of calmodulin with subcellular fractions isolated from rat liver.

Calmodulin associated with rat liver mitochondria has been found to belong to a contaminant membranous fraction which contains different subcellular membranes. The concentration of calmodulin in this fraction is relatively high, about 1.6 micrograms/mg protein, and can not be decreased with EGTA. The calmodulin-rich membranous fraction seems to contain cytoskeletal proteins which could be responsible for the binding of calmodulin.

Animals↗

PubMed1986

Simultaneous determination of tocopherols, ubiquinols, and ubiquinones in blood, plasma, tissue homogenates, and subcellular fractions.

A fast single-step lipid extraction procedure and high-performance liquid chromatography with in-line uv and electrochemical detection are used for the simultaneous quantitative determination of tocopherols, ubiquinols, and ubiquinones in blood, plasma, tissue homogenates, and subcellular fractions. The compounds of interest can be quantitatively extracted into hexane from a sodium dodecyl sulfate-treated aqueous homogenate after precipitation of protein by addition of an equal volume of ethanol. alpha-, gamma-, and delta-Tocopherol, ubiquinol 9, ubiquinol 10, and ubiquinones 9 and 10 can be well separated on a reversed phase column. Ubiquinones are detected at 275 nm by the uv detector, and ubiquinols and tocopherols by the electrochemical detector in the oxidative mode. Quantitation is done by comparing chromatographic peak heights to those of a standard solution containing known amounts of tocopherols, ubiquinols 9 and 10, and ubiquinones 9 and 10, analyzed under identical conditions. The high sensitivity of the electrochemical detection allows operation at low potentials (+0.5 V) with low detector response, but high selectivity for the easily oxidizable tocopherols and ubiquinols and decreased baseline noise. The uv detection limits the overall sensitivity of the procedure to 2 pmol ubiquinone, corresponding to 0.1 microM ubiquinone in the lipid extract. The ranges of values obtained for rat and guinea pig tissues, for rat liver mitochondria, and for blood and plasma from rats and humans are given.

Adipose Tissue, Brown↗

PubMedDate not supplied

[Alterations in activity of the ATPase systems in subcellular fractions of brain and spinal cord in the preclinical period of botulinum poisoning].

Under conditions of the C type botulinic intoxication of rats blockade of cholinergic synaptic transmission and development of paralytic syndrome followed the distinct alteration in activity of the ATPase systems in various subcellular fractions of brain and spinal cord. This suggests that the toxin affects the various intracellular metabolic reactions related directly or indirectly to active transmembrane transport of ions.

Adenosine Triphosphatases↗

PubMedDate not supplied

[Radioactivity distribution in the subcellular fractions of reproductive tract and skeletal muscle tissue in rat and rabbit embryos after in vitro exposure to 1 alpha, 2 alpha-3H(p)-testosterone and 5 alpha-dihydro-1 alpha, 2 alpha(p)-testosterone].

In the in vitro experiments the distribution of radioactivity was studied in the subcellular fractions of the reproductive system and muscles of the rat embryos on the 14-, 16- and 18th days and of the rabbit embryos on the 18th and 20-22nd days of development after the preincubation in the medium with 1 alpha, 2 alpha-3H(n)-testosterone (T-3H). The total consumption of T-3H per mg of tissue is higher in the reproductive system than in the muscles and attains the maximum in the rabbit on the 21st and in the rat on the 18th day of development. The ratio of radioactivity in the nuclear and cytoplasmic fractions per mg of protein changes at the critical period of somatic sex differentiation: in the rabbit between the 20th and 21st and in the rat between the 16th and 18th days of development. The radioactivity in the nuclear fraction is markedly higher than in the cytoplasmic one on the 21st day in the rabbit and on the 18th day in the rat and, on the contrary, lower at all preceding times. The radioactivity in the microsomal fraction is higher than in the cytosol. The distribution of radioactivity of 5 alpha-dihydro-1 alpha, 2 alpha(n)-testosterone (DHT-3H) was studied on the 20th and 21st days of development in the rabbit embryos. No changes in the nucleocytoplasmic ratio of radioactivity was found, but the radioactivity decreased in all fractions on the 21st day.

Animals↗

PubMed1984

Opiate binding to subcellular fractions from guinea pig ileum.

Binding of 3H-etorphine and 3H-D-Ala2-D-Leu5-enkephalin to opiate receptors in synaptosomal and microsomal fractions prepared from guinea pig ileum homogenates has been studied. It is found that the dissociation constants for etorphine from all fractions are the same. The binding capacity for etorphine for the purified synaptosomal fraction is greater than for other fractions by a factor of 5. For the enkephalin derivative binding to the microsomal fraction the dissociation constant is greater than for etorphine while the binding capacity is a factor of 3 lower. These results are in contrast to the case for binding to central nervous system subcellular fractions.

Animals↗

PubMed1986

[Effect of ethanol on the DNA-polymerase activity in the liver subcellular fractions of adult and old rats].

The effect of 5% ethanol on DNA polymerase activity in nuclei, mitochondria, microsomes and cytosol of intact and regenerating liver of adult and old rats has been studied. No changes in DNA polymerase activity were detected in subcellular fractions of adult rat liver. On the contrary, the increased activity of intact liver nuclei and decreased activity of regenerating liver microsomes was observed with ageing. These age-dependent peculiarities of DNA polymerase activity in response to 5% ethanol may be related to changes in the enzyme molecules or microenvironment associated with ageing.

Aging↗

PubMed1985

Subcellular fractionation of rectal biopsy homogenates from patients with inflammatory bowel disease.

Rectal biopsy specimens from control subjects and from patients with Crohn's colitis, non-rectal Crohn's disease, and acute ulcerative colitis were homogenized in isotonic sucrose and subjected to analytical subcellular fractionation by sucrose density gradient centrifugation. The gradient fractions and tissue homogenates were assayed for marker enzymes for the principal organelles: 5'nucleotidase (plasma membrane), malate dehydrogenase (mitochondria), catalase (peroxisomes), lactate dehydrogenase (cytosol), N-acetyl-beta-glucosaminidase (lysosomes), and neutral-alpha-glucosidase (endoplasmic reticulum). In normal tissue there was a distinct plasma membrane peak at density 1.12 g/ml. In tissue from patients with Crohn's disease the activity was increased approximately twofold even when the rectum showed no evidence of histological involvement. A second plasma membrane component was noted in Crohn's disease at density 1.19 g/ml. The total activity of the mitochondrial enzyme was similar in the various patient groups, but there was evidence of mitochondrial damage. There were no significant alterations in activity and density gradient distributions of catalase or of neutral alpha-glucosidase in the various patient groups, although less membrane-bound lactate dehydrogenase was noted in the patients with inflammatory bowel disease. There was a reduction of both cytosolic and particulate N-acetyl-beta-glucosaminidase in ulcerative colitis and a selective reduction in particulate activity in non-rectal Crohn's disease, demonstrating lysosomal alterations in these disorders. These results indicate selective and specific alterations in the principal subcellular organelles, especially the plasma membrane, lysosomes, and mitochondria, in the inflammatory bowel disease.

Cell Membrane↗

PubMed2000

Aldehyde dehydrogenase (ALDH) 2 associates with oxidation of methoxyacetaldehyde; in vitro analysis with liver subcellular fraction derived from human and Aldh2 gene targeting mouse.

A principal pathway of 2-methoxyethanol (ME) metabolism is to the toxic oxidative product, methoxyacetaldehyde (MALD). To assess the role of aldehyde dehydrogenase (ALDH) in MALD metabolism, in vitro MALD oxidation was examined with liver subcellular fractions from Japanese subjects who carried three different ALDH2 genotypes and Aldh2 knockout mice, which were generated in this study. The activity was distributed in mitochondrial fractions of ALDH2*1/*1 and wild type (Aldh2+/+) mice but not ALDH2*1/*2, *2/*2 subjects or Aldh2 homozygous mutant (Aldh2-/-) mice. These data suggest that ALDH2 is a key enzyme for MALD oxidation and ME susceptibility may be influenced by the ALDH2 genotype.

Acetaldehyde↗

PubMed1995

Intracellular distribution of Hg2+ applied to epidermis in mice. Analysis of subcellular fractions.

To analyze the permeation of Hg2+ in the epidermis as contact dermatitis allergen, the carrier substances from the HgCl2-treated epidermis were isolated. The peak amount of Hg2+ in the epidermis of mouse tail skin was observed at 12 h after the painting. Thereafter, it remained almost stationary. In the analysis of subcellular fractions, the nuclei fraction showed the highest Hg2+ incorporation, while the soluble protein fraction showed the lowest.

Animals↗

PubMed1983

Analytical subcellular fractionation of guinea pig peritoneal macrophages: preparation of purified plasma membranes.

A method using sucrose gradient centrifugation is described for the purification of plasma membranes of guinea pig peritoneal macrophages. The subcellular fractions obtained have been submitted to a biochemical and ultrastructural analysis. Two plasma membrane markers, 5'-nucleotidase and alkaline phosphodiesterase I, have been assayed at the same time as markers for other subcellular organelles, DNA (nuclei), succinic dehydrogenase (mitochondria), inosine diphosphatase (endoplasmic reticulum), and acid phosphatase (lysosomes). The exposure of the plasma membranes to a low concentration of digitonin allowed us to obtain their high purification. They are only contaminated by 2-3% of other cell components present in the macrophages homogenate. The representative ultrastructural technique used has confirmed the purity of the plasma membranes isolated.

Animals↗