UMLS:C0011570 - FACTA Search

Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Target Concepts:

Query: UMLS:C0011570 (depression)
172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The absorption and circular dichroic (CD) spectra of purple membrane films in which the plane of the membranes is oriented perpendicular to the incident beam are compared with the solution spectra. This enables one to relate structural features of the purple membrane to a coordinate system as defined by a normal to the membrane plane and two mutually perpendicular in-plane axes. The film and solution absorption spectra were similar except for a relative depression in the 200 - 225-nm region of the film spectrum. However, the CD spectra showed significant differences in the visible region, where the biphasic band in the solution spectrum was replaced by a single positive band at 555 nm in the film spectrum and in the far ultraviolet region, where the 208-nm band was deleted from the film spectra of the native and regenerated membranes. Moreover, a small shoulder occurred at 208 nm in the film spectrum of the bleached membrane. The near ultraviolet spectra also showed differences, whereas the 317-nm band remained essentially the same for both spectra. Based on excitonic interpretations of the visible and far ultraviolet spectra the following conclusions were reached: (a) a relatively strong in-plane monomeric interaction occurs between te retinyl chromophore and apoprotein; (b) the helical axes of the native and regenerated membrane proteins are oriented primarily normal to the membrane plane; and (c) the helical axes of the bleached membrane proteins are tilted more in-plane than the axes of the native or regenerated membrane. Additional conclusions were that an interaction occurs between an in-plane magnetic dipole moment of the retinyl chromophore and probably an in-plane electric dipole moment of a nearby aromatic amino acid(s), and that although the membrane is anisotropic with respect to coupling between electric and magnetic moments of the aromatic amino acids, the transition dipole moments of the aromatic amino acids are not preferentially oriented in either direction.
...
PMID:Interpretation of the absorption and circular dichroic spectra of oriented purple membrane films. 26 27

Consumption of n-3 polyunsaturated fatty acids (n-3 PUFAs) is associated with a reduced incidence of coronary arterial diseases. Dietary n-3 PUFAs act via several mechanisms. They depress plasma lipids, especially triglycerides (TGs), by inhibiting hepatic TGs and possibly apoprotein synthesis. They replace arachidonic acid (AA) in phospholipid pools with eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA). EPA and DHA, when released, inhibit cyclooxygenase and lipoxygenase and reduce eicosanoid synthesis, particularly thromboxane (TXA2) and leukotriene B4 (LTB4), by platelets and macrophages. Reduction of the proaggregatory, vasoconstrictive TXA2 decreases the thrombotic tendency of platelets. This is augmented by the limited depression of the vasoactive antiaggregatory prostacyclin (PGI2) and the generation of antiaggregatory prostaglandin I3 (PGI3) from EPA. The n-3 PUFAs also depress eicosanoid metabolism in platelets, monocytes, and macrophages, and thereby may retard the initiation and progress of atherogenesis. n-3 PUFAs reduce blood pressure and blood viscosity and modulate membrane fluidity and associated enzyme and receptor functions. The collective effects of n-3 PUFAs may account for the reduction in coronary arterial disease in populations consuming foods containing n-3 PUFAs.
...
PMID:Dietary n-3 polyunsaturated fatty acids and amelioration of cardiovascular disease: possible mechanisms. 198 44

Diets currently used to produce atherosclerotic lesions in mice are often undefined and cause accumulation of fat in the liver and gallstone formation. Therefore, synthetic low and high fat diets of known composition were formulated in this study. A synthetic diet containing 50% sucrose, 15% cocoa butter, 1% cholesterol, and 0.5% sodium cholate was found to produce a depression in high density lipoprotein cholesterol (HDL-C) and an elevation of very low density lipoprotein (VLDL) and low density lipoprotein cholesterol (LDL-C) in the atherosclerosis-susceptible strain, C57BL/6J. This diet was able to consistently produce aortic lesions and led to a decrease in liver damage and gallstone formation. The synthetic low fat diet did not produce HDL-C levels as high as those found in mice fed chow, but resulted in similar VLDL/LDL-C levels. Lipoprotein and apolipoprotein parameters were compared in C57BL/6J and the atherosclerosis-resistant strain, C3H/HeJ, consuming the synthetic low fat or high fat diets. As reported earlier, when consuming a high fat diet C57BL/6J mice have significantly lower HDL-C and apoA-I levels than C3H/HeJ mice. Further analysis shows that the molar ratio of plasma HDL-C to apoA-I is significantly lower in C57BL/6J mice, suggesting that HDL in the susceptible strain has a lower cholesterol-carrying capacity. This conclusion is consistent with the observation that the HDL particle size is smaller for C57BL/6J mice than for C3H/HeJ. Both strains increased their apoE levels when fed the synthetic high fat diet, but C3H/HeJ mice had higher levels of apoE on both diets. The major response to consumption of the high fat diet for both strains was an increase in apoB-48 from 5 micrograms/ml on a low fat diet to 54 and 109 micrograms/ml for C57BL/6J and C3H/HeJ, respectively. ApoB-100 showed minimal response to the high fat diet. The defined high fat diet can be used to study atherosclerosis in the mouse since it produces aortic lesions but reduces or eliminates other pathological changes such as gallstone formation and liver damage.
...
PMID:Synthetic low and high fat diets for the study of atherosclerosis in the mouse. 238 Jun 34

The protective effect of SKF 525-A on the suppression of cytochrome P-450 content and monooxygenase activities by treatment with CoCl2 and polyriboinosinic acid-polyribocytidylic acid [poly(I.C] was compared as a part of studies of suppression of drug metabolizing enzymes by interferon inducers. Induction of heme oxygenase activity by CoCl2 and poly (I.C) was not altered by simultaneous treatment with SKF 525-A. Depression of cytochrome P-450 content and benzphetamine N-demethylase activity by treatment with CoCl2 was prevented by co-treatment with SKF 525-A. This effect was explained by the prevention of release of heme from cytochrome P-450 by forming metabolic intermediate complexes with metabolites of SKF 525-A. On the other hand, poly(I.C) significantly suppressed P-450 content and benzphetamine N-demethylase and benzo [a] pyrene hydroxylase activities, even under simultaneous treatment with SKF 525-A. This inhibition by poly (I.C) was accompanied by weak staining of proteins corresponding to cytochrome P-450 in SDS gel electrophoresis. In addition, the activity of non-heme enzyme, 4-hydroxybiphenyl glucuronyltransferase, was suppressed by treatment with poly (I.C) but not by CoCl2-treatment. These findings strongly suggested that, unlike CoCl2, poly (I.C) suppressed cytochrome P-450 content and monooxygenase activities due to decreased synthesis or increased degradation of the apoprotein of cytochrome P-450 with slight contribution of the induced heme oxygenase.
...
PMID:Effect of co-administration of interferon inducer, polyriboinosinic acid-polyribocytidylic acid, with SKF 525-A on hepatic drug metabolizing enzymes of rats. 309 97

The effect of variable doses of ethanol on plasma lecithin: cholesterol acyltransferase (LCAT) activity was examined in male, atherosclerosis-susceptible squirrel monkeys over a 12-month period. Primates were divided into three groups: 1) Controls fed isocaloric liquid diet; 2) Low Ethanol monkeys given liquid diet with vodka substituted isocalorically for carbohydrate at 12% of calories; and 3) High Ethanol animals fed diet plus vodka at 24% of calories. There were no significant differences between the treatments in serum glutamate oxaloacetate transaminase (SGOT), a measure of liver function. However, plasma LCAT activity (% esterification/min) measured in vitro was significantly reduced in High Ethanol monkeys while cholesterol esterification was elevated in the Low Ethanol group and intermediate in Controls. Similarly, the in vivo appearance of radiolabeled cholesteryl ester in high density lipoproteins (HDL) following the intravenous injection of 3H mevalonolactone was highest in the Low Ethanol primates, intermediate in Controls and significantly lower in monkeys fed the high alcohol diet. In vitro measurement of LCAT enzyme efficiency was similar for the three groups while substrate efficiency was lower in the High Ethanol treatment. Although LCAT activator (apoprotein A-I) was not markedly altered by dietary ethanol and the concentration of LCAT substrates (HDL free cholesterol and phosphatidyl choline) was significantly elevated in the High Ethanol group, subtle modifications in substrate-product composition may account for the observed reduction in cholesterol esterification. These include potential substrate and/or product LCAT inhibition resulting from increased concentrations of plasma free cholesterol, HDL lysophosphatidyl choline, and higher HDL2/HDL3 subfraction ratios, as well as alterations in HDL phospholipid fatty acid profiles in the High Ethanol group. Results from this study provide the first evidence of an anomalous enhancement in LCAT activity in nonhuman primates fed ethanol at 12% of calories and a marked depression in cholesterol esterification at the 24% dose which may be due to substrate alterations and product inhibition prior to overt biochemical evidence of liver dysfunction.
...
PMID:Effect of ethanol on lecithin:cholesterol acyltransferase (LCAT) activity. 399 6

The levels of cytochrome P-450, cytochrome b5, aminopyrine N-demethylase, and benzo[a]pyrene hydroxylase were depressed in hepatic microsomes following treatment of mice with the interferon inducer poly rI.rC. The decrease in the hepatic mixed function oxidase system was accompanied by an increase in the incorporation of amino acids into total microsomal protein. Fractionation of solubilized microsomes using a Sephacryl S-200 gel filtration column demonstrated that the increase in amino acid incorporation tended to be associated with proteins with molecular weights under 67 000. The fractions which contained cytochrome P-450 were further separated using a DEAE cellulose column. The amount of labelled amino acids associated with the cytochrome P-450 fractions was uniformly depressed in preparations from poly rI.rC treated animals compared with saline-treated controls. These results suggest that poly rI.rC causes a depression in the rate of synthesis of the apoprotein of cytochrome P-450 while increasing the incorporation of amino acids into other hepatic proteins. The decrease in apocytochrome P-450 synthesis explains the marked loss of drug biotransformation which occurs following induction of interferon.
...
PMID:Inhibition of the synthesis of hepatic cytochrome P-450 by the interferon-inducing agent poly rI.rCi. 673 84

In the rat testis, 7 days after hypophysectomy, the microsomal content of cytochrome P-450 decreased to a negligible level. The sodium dodecyl sulfate gel electrophoresis of the microsomal preparation did not reveal a decrease in apocytochrome P-450; however, in this preparation, heme was undetectable. The latter did not reflect decreases in the activities of the heme biosynthesis enzymes. Also, an increase in heme oxygenase activity did not appear responsible for the suppression of the cytochrome levels. The cellular basis for the depression of the cytochrome was explored by measuring the incorporation of [14C]delta-aminolevulinate into the testicular microsomal and mitochondrial hemoproteins, and determining the relative affinity of microsomal heme for the endoplasmic reticulum membranes. In comparison with the sham-operated animals, in hypophysectomized rats, the specific 14C activity of heme in mitochondrial fraction was not decreased; however, that of the microsomal fraction was markedly reduced. The latter appeared to reflect a lowered binding affinity of the apoprotein moiety of cytochrome P-450 for heme. The treatment of hypophysectomized rats with human chorionic gonadotropin partially restored the normal level of the cytochrome. It is suggested that the anterior pituitary hormones control the level of cytochrome P-450 in the testis through factors which do not involve the production of heme; rather, the control appears to involve the processes of assembly of the hemoprotein and the association of the heme molecule with the apoprotein.
...
PMID:Dissociation of heme metabolic activities from the microsomal cytochrome P-450 turnover in testis of hypophysectomized rats. 674 60

Carrageenan-induced granuloma was used to study the apoprotein and RNA content, and catalytic activities of several cytochrome P-450 isozymes in liver. This model allowed discrimination between acute and chronic phases of experimental inflammation. The expression of most isozymes studied (CYP2D, CYP2E1, CYP3A1 and CYP4A) was reduced to 20% of the control level during the acute phase and partially recovered (30-60% of control group) during the chronic phase. CYP2B1 content was decreased to 65% of control during the acute and chronic phases of inflammation. RNA (CYP2B1 and CYP2E1) showed a strong depression during the acute phase and recovered during the chronic phase, without differences between isoenzymes. In most cases, there was a good correlation between the apoprotein content of isozymes and related activities. Our results show that the depletion of cytochrome P-450 induced by inflammation depends on the severity of the disease. Experimental inflammation equally affect the transcription of CYP2B1 and CYP2E1, so differences in apoprotein content and related activities between isozymes may due to differential posttranscriptional regulation.
...
PMID:Effect of carrageenan-induced granuloma on hepatic cytochrome P-450 isozymes in rats. 760 2

Interferon and interferon inducers are well known to depress hepatic cytochrome P-450 (P-450). Previous reports have suggested that all constitutive members of the P-450 family of proteins are affected in this manner, whereas inducible P-450s--including cytochrome P-4503A1 (CYP3A1)--are resistant to the effects of interferons. We examined the effect of interferon [produced in response to polyinosinic acid-polycytidylic acid (polyIC; 10 mg/kg) administration] on the induction of CYP3A1 in the female rat by the macrolide antibiotic troleandomycin (TAO; 200 mg/kg), and the antiglucocorticoid pregnenolone-16 alpha-carbonitrile (PCN; 300 mg/kg). The induction of CYP3A1 was characterized by erythromycin N-demethylation, Western blotting, and mRNA quantitation with a specific oligonucleotide cDNA probe. PCN-mediated induction of erythromycin metabolism was depressed by 85% following polyIC administration. PolyIC depressed the induction of CYP3A1 apoprotein by TAO (84%) and PCN (73%). The depression of enzyme activity and protein were accompanied by a corresponding decrease in hepatic CYP3A1 mRNA. It is concluded that CYP3A1 is sensitive to the depressant effects of interferon, and that interferon appears to act at a pretranslation step that is independent of the induction process per se.
...
PMID:Modulation of rat hepatic CYP3A1 induction by the interferon inducer polyinosinic acid-polycytidylic acid (polyic). 768 58

The activation of host defense mechanisms has been shown to cause a depression in hepatic cytochrome P450-mediated metabolism in rodents and humans. In a previous study, it was demonstrated that the Gram-positive bacteria Listeria monocytogenes causes a down-regulation of hepatic cytochrome P450 and related substrate metabolism as a result of a pretranslational depression of apoprotein synthesis. The objectives of this study were to determine whether the effect of listeria on hepatocyte cytochrome P450 involves hepatic nonparenchymal cells and whether the hemolysin, secreted only by hemolytic forms of the bacteria, plays any part in mediating this effect. Total cytochrome P450 levels as well as ethoxyresorufin-O-dealkylase (EROD) and benzyloxyresorufin-O-dealkylase (BROD) activities were significantly reduced in hepatic microsomes isolated from mice infected in vivo for 48 h with 15U listeria, whereas the same dose of the avirulent non-hemolytic M3D strain had no effect. Listeria (15U) significantly depressed hepatocyte EROD and BROD activities after 24 h incubations with liver cell cultures containing hepatocytes and nonparenchymal cells, as the result of both a direct effect on the hepatocyte and an interaction of listeria with hepatic nonparenchymal cells. The M3D strain of listeria had no effect on cytochrome P-450-mediated metabolism in isolated cells, confirming that hemolysin is an essential component of the mechanism responsible for the down-regulation of cytochrome P450 during listeria infections.
...
PMID:Factors involved in the down-regulation of cytochrome P450 during Listeria monocytogenes infection. 780 32

1 2 3 Next >>