Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: DrugBank:APRD00080 (Leaf)
 21,685 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Airborne dust is toxic for cells cultured in vitro and able to transform these cells to cancerous. The effect of extracts from atmospheric dust has been investigated. The dust samples were extracted by means of DMSO alone or in combination acetone-DMSO. Dosage of the extract was done according to its benzo(a)pyrene content (mug/ml medium). Dust extract with a concentration of 1 mug benzo(a)pyrene/ml exerted a toxic effect upon mouse macrophages (cell line IC-21) and human lymphocytes after stimulation. The degree of toxicity was estimated from the percentage of damaged cells seen in the dye exclusion test and from the amount of lactate dehydrogenase and lactate released into the medium in the case of macrophages. In the case of lymphocytes the degree of toxicity was estimated from the extent of inhibition of DNA synthesis. In the carcinogenicity test, hamster kidney cells were first treated with the extract and then incubated with Simian Virus (SV-)40. Treatment of the cell cultures with extract from airborne dust in a concentration of 0.01 and 0.1 mug benzo(a)pyrene/ml clearly enhances the rate of transformation caused by SV 40.
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PMID:[The effect produced by fine-dust extracts on cells in vitro, with particular regard to cancerogenic components (author's transl)]. 18 83

The technique of reversible hemolysis represents one approach which may be used to study transport regulation in nucleated red cells. After 1 h of incubation at 37 degrees C, 88% of the ghosts regained their permeability barrier to L-glucose. In these ghosts, the carrier-mediated rate of entry of 3-O-methylglucose was more than 10-fold greater than the rate in intact cells. Glyceraldehyde-3-phosphate dehydrogenase prevented ghosts from resealing when it was present at the time of hemolysis. Albumin, lactic dehydrogenase and peroxidase did not have this effect. Sugar transport rate could not be tested in the unsealed ghosts. Two possible mechanisms for the effect of hypotonic hemolysis on sugar transport rate were discussed: (1) altered membrane organization and (2) loss of intracellular compounds which bind to the membrane and inhibit transport in intact cells.
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PMID:Sugar transport in reversibly hemolyzed avian erythrocytes. 127 11

The relationship between biochemical changes in bronchoalveolar lavage fluid (BALF), serum and the lung of different dustexposed rats was studied. Wistar rats were divided into 5 groups: 1. Xingkong chrysotile asbestos (CH-As); 2. Dust in a sieve selection workshop of Xingkong asbestos mine (Dust-Wo); 3. Silica group (SiO2); 4. Titanium dioxide (TiO2) and 5. Normal control group (Control). All the rats were killed in three months after experiment. The results showed that the level of alveolar macrophages (AM), lactic dehydrogenase (LDH) and acid phosphatase (AcP) in each group was marked by related to collagen, lung fat, ceruloplasmin (Cp) and hydroxyproline (HoP) by r and t-test. Among the LDH from BALF, culture fluid and serum, there was also a marked relationship. So the authors pointed out that the BALF especially AM and LDH test could serve as a good and valuable index for detection the condition of pneumoconiosis.
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PMID:[The relationship of biochemical changes among bronchoalveolar lavage fluid serum and lung on dust-exposed rats]. 166 Aug 48

A quantitative evaluation of lectin binding to adult rat hepatocyte cell surfaces was done using cells isolated by two different collagenase perfusion methodologies and cultured as monolayers with two different tissue culture media formulations (protocol I vs. protocol II). The presence of alpha-D-mannosyl and alpha-D-glucosyl groups was detected by the binding of Concanavalin A (Con A), Lens culinaris agglutinin (LCA), and Pisum sativum agglutinin (PSA) to freshly isolated cells. Furthermore, beta-D-galactose [Ricinus communis agglutinin (RCA)] and sialic acid residues [wheat germ (WGA)] were also found. Protocols I and II served as models for evaluation of: a) the stripping effect of collagenase separation procedures, b) the restoration in culture of collagenase-stripped sugar residues, c) the effect of the culture environment on cell viability [as measured by lactic acid dehydrogenase (LDH) leakage] and the protein content of hepatocytes, and d) the presence of cell surface sugar residues as a function of culture duration. The ultrastructural morphology of freshly isolated and cultured hepatocytes was also evaluated. These studies indicated that a decline in lectin binding invariably occurred earlier than a massive leakage of LDH and a decrease in the protein content of the cells in culture. Ultrastructurally, autophagocytosis was an early phenomenon in cells isolated and cultured by protocol I, which was also inferior to protocol II regarding the preservation of hepatocyte glycocalyces. Sugar residues lost due to the collagenase-stripping effect were restored, as shown by lectin binding, within the first 24 h of culture. This stripping effect was confirmed by quantitative evaluations of lectin binding to hepatocytes in culture after an incubation with collagenase. This study shows that the binding of peroxidase-labeled lectins is a useful tool for quantitative evaluation of the sugar composition of hepatocyte cultures.
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PMID:A quantitative analysis of lectin binding to adult rat hepatocyte cell surfaces. 283 55

These studies addressed the question of the in vivo distribution of rat brain hexokinase (HK), and whether physiologically relevant changes in the glycolytic rate are accompanied by changes in the distribution of HK. Homogenates of fresh tissue showed only 11-15% of the overt (assayable without added detergent) HK to be soluble (found in high-speed centrifugation supernatant fractions) when homogenization was begun within 15-20 s of sacrifice. Freeze-blown rat brain tissue also was used, coupled with a new technique wherein it was homogenized as it thawed in a buffered sucrose solution containing 1 mM EDTA. In tissue sampled 15 min (anesthetized) or 60 min (waking) after ip Nembutal injection (40 mg/kg), 23% of the overt HK and 79% of the total lactate dehydrogenase were soluble. The average phosphocreatine content of these and similar homogenates had decreased only 23% from in vivo levels, while ATP had decreased by 65%, due to the combined effects of a high level of endogenous ATPase, chelation of Mg2+ by EDTA, and the greater stability of Mg-ATP2- relative to Mg-ADP1-. These data indicated that the tissue experienced, at most, the equivalent of 6 s of complete ischemia prior to the completion of homogenization. Synaptosomes derived from rat and chicken cerebra were incubated at 37 degrees C in a physiological salt solution containing 10 mM glucose. Addition of veratridine has been shown to stimulate glycolysis and oxidative phosphorylation two- to threefold (H. T. Kyriazi and R. E. Basford (1986) J. Neurochem., in press), but did not alter the HK distribution, as 21% was found in the supernatant fractions of both control and veratridine-stimulated synaptosomes treated with digitonin. These results indicate that in brain tissue, large net movements of HK on and off the outer mitochondrial membrane do not occur, and thus play no role in the regulation of glycolysis.
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PMID:An examination of the in vivo distribution of brain hexokinase between the cytosol and the outer mitochondrial membrane. 294 9

Glutathione-depleted hepatocytes, by incubation with diethylmaleate (DEM) or phorone (2,6-dimethyl-2,5-heptadiene-4-one), i.e., substrates of the GSH S-transferases (EC 2.5.1.18), showed rates of gluconeogenesis from various precursors significantly lower than controls; however the rate of glucose synthesis from fructose was similar to that of controls. Isolated hepatocytes from rats pretreated with those substrates 1 h before isolation to deplete hepatic glutathione (GSH) also showed a decrease of the rate of gluconeogenesis from lactate plus pyruvate. Incubation of hepatocytes with L-buthionine sulfoximine, a specific inhibitor of gamma-glutamyl-cysteine synthetase (EC 6.3.2.2), resulted in a decreased rate of gluconeogenesis from lactate plus pyruvate only when GSH values were lower than 1 mumol/g cells. Freeze-clamped livers from GSH-depleted rats showed a higher concentration of malate and glycerol 3-phosphate, indicating that GSH depletion probably affects phosphoenolpyruvate carboxykinase and glycerol-3-phosphate dehydrogenase activities. Several indicators of cell viability, such as lactate dehydrogenase leakage, malondialdehyde accumulation, ATP concentration, or urea synthesis from different precursors, were not affected by GSH depletion under the experimental conditions used here. Besides, the GSH/GSSG ratio remained unchanged in all cases.
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PMID:Effects of glutathione depletion on gluconeogenesis in isolated hepatocytes. 402 24

Cooling and warming rates are known to be important determinants of viability for cryopreserved cells, but optimal rates have not previously been determined for any whole organ. In this study, rabbit kidneys, permeated with 2 M glycerol were cooled to -80 degrees C at four rates varying from 1 degrees C/hr to 3.1 degrees C/min and then rewarmed at four rates from 1 degrees C/hr to 4.2 degrees C/min, giving 16 experimental treatments. After gradual deglycerolization at 10 degrees C, each kidney was autografted and observed for 30 min. Assessment was by measurement of vascular resistance, immediate post-thaw lactate dehydrogenase (LDH) release, gross appearance, light- and electron microscopy, and tissue K+/Na+ ratio 30 min after transplantation. The best results were obtained after cooling at 1 degrees C/hr; warming rate had little apparent influence on the criteria used to assess function with the exception of LDH release, which indicated a preferred warming rate around 1 degrees C/min. Histological studies revealed extensive vascular damage, notably to the glomerular capillaries, that was minimized by very slow cooling. Freeze substitution, carried out on samples removed at -80 degrees C, demonstrated extensive ice formation in the interstitial space and, at the faster cooling rates, in the glomerular capillaries. Intracapillary ice formation was reduced in the kidneys cooled at 1 degrees C/hr.
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PMID:Effect of cooling and warming rate on glycerolized rabbit kidneys. 639 15

Freeze-dried sagittal, whole-body sections of 10-day-old rats were incubated for lactic dehydrogenase (LDH) using different media in the presence of the inhibitors urea and fluoropyruvate. Phenazine methosulfate (PMS) and menadione, which are regularly used in current histochemical media and are believed to promote the demonstration of LDH activity, were also added and shown to be insufficient for the demonstration of total LDH activity, and PMS even seemed to have an inhibitory effect on LDH activity in oral epithelium. However, cumulated data from the different incubations show that the oral epithelium of developing rats may contain two different types of LDH, one in the basal cells with possibly aerobic characteristics, and another in the spinosum/granulosum cells with anaerobic characteristics.
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PMID:Lactate dehydrogenase in developing rat oral epithelium. 669 May 95

Streptococcus mutans, an important aetiological agent of dental caries, is known to transport glucose via the phosphoenolpyruvate (PEP) phosphotransferase system (PTS). An alternative non-PTS glucose transport system in S. mutans Ingbritt was suggested by the increased ATP-dependent phosphorylation of glucose and the presence of higher cellular concentrations of free glucose in cells grown in continuous culture under PTS-repressed conditions compared to those resulting in optimal PTS activity. A method was developed for the preparation of membrane vesicles in order to study this system in the absence of PTS activity. These vesicles had very low activity of the cytoplasmic enzymes, glucokinase, pyruvate kinase and lactate dehydrogenase. This, coupled with the lack of glycolytic activity and the inability to transport glucose, suggested that the vesicles would also be deficient in PTS activity because of the absence of the general soluble PTS proteins, Enzyme I and HPr, required for the transport of all PTS sugars. Freeze-fracture electron microscopy and membrane H(+)-ATPase analysis indicated that over 90% of the vesicles had a right-side-out orientation. Vesicles from cells grown in continuous culture under PTS-dominant and PTS-repressed conditions both exhibited glucose counterflow. This indicates the presence of a constitutive non-PTS carrier in the organism capable of transporting glucose and utilizing ATP for glucose phosphorylation. Analysis of growth yields of cells grown under PTS-repressed and PTS-optimal conditions suggests that ATP, or an equivalent high energy molecule, must be involved in the actual transport process. This analysis is consistent with an ATP-binding protein model such as the Msm transport system reported by R. R. B. Russell and coworkers (J Biol Chem 267, 4631-4637), but it does not exclude the possibility of a separate permease for glucose.
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PMID:Vesicles prepared from Streptococcus mutans demonstrate the presence of a second glucose transport system. 800 May 34

In order to characterize the protein composition of the outer membrane of Borrelia burgdorferi, we have isolated inner and outer membranes by using discontinuous sucrose density step gradients. Outer and inner membrane fractions isolated by this method contained less than 1 and 2%, respectively, of the total lactate dehydrogenase activity (soluble marker) in cell lysate. More importantly, the purified outer membranes contained less than 4% contamination by the C subunit of F1/F0 ATPase (inner membrane marker). Very little flagellin protein was present in the outer membrane sample. This indicated that the outer membranes were relatively free of contamination by cytoplasmic, inner membrane or flagellar components. The outer membrane fractions (rho = 1.19 g/cm3) contained 0.15 mg (dry weight) of protein per mg. Inner membrane samples (rho = 1.12 g/cm3) contained 0.60 mg (dry weight) of protein per mg. Freeze-fracture electron microscopy revealed that the outer membrane vesicles contained about 1,700 intramembranous particles per micron 2 while inner membrane densities for inner and outer membranes. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and nonequilibrium pH gel electrophoresis-SDS-PAGE analyses of inner and outer membrane samples revealed several proteins unique to the inner membrane and 20 proteins that localized specifically to the outer membrane. This analysis clearly shows that the inner and outer membranes isolated by this technique are unique structures.
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PMID:Isolation and partial characterization of Borrelia burgdorferi inner and outer membranes by using isopycnic centrifugation. 800 66


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