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

Previous studies from this laboratory indicated that inorganic and organic anions inhibit the unidirectional influx and net transport of the folate analog methotrexate in mammalian cells. Studies were undertaken to establish whether anions retained in uremia might inhibit the membrane transport of folates. Methotrexate was utilized as a model folate compound and its transport was determined in the Ehrlich ascites tumor cell. Influx of methotrexate was inhibited when cells were suspended into sera or ultrafiltrates of sera (pH adjusted to 7.4 by regulation of PCO2) from uremic patients, an effect that was decreased after the patient underwent hemodialysis or peritoneal dialysis. The inhibitory effect of uremic sera correlated well with the level of retained anions as estimated from the "anion gap," but could not be related to changes in osmolality, blood urea nitrogen (BUN), sodium, potassium, calcium, or magnesium. While inhibiting the influx of methotrexate, inorganic anions did not displace methotrexate from albumin binding sites. Anionic inhibition of the membrane transport of 5-methyl [14C] tetrahydrofolate was also demonstrated and this was shown to be accompanied by a depression in the rate of incorporation of the labeled 14C moiety into nucleic acids and protein. The data suggested that transport of folates is impaired in uremia and raises the possibility that whatever the measured blood folate level in the uremic individual with retained anions, the rate of uptake of folates into folate-dependent tissues which this blood folate level will sustain may be reduced.
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PMID:Inhibition of the membrane transport of folates by anions retained in uremia. 118 41

A study was made of the effect of sporofusarin (mycotoxin produced by Fusarium Sporotrichiella v. Sporotrichoides) on the functional activity and permeability of cell membranes of the isolated perfused rat liver. Sporofusarin (in the end concentration of 5.9 . 10(-5) M) produced a marked depressive effect on the rate of bile, formation, urea synthesis and oxygen consumption, and also caused an early and marked disturbance of permeability of the lysosomal and plasma membranes of hepatocytes (an increase in the activity of the enzymes--beta-acetylglucosaminidase, beta-glucuronidase, arylsulfatases A and B, beta-galactosidase in the supernatant fluid of liver homogenate and in the perfusata). It is supposed that depression of the functional activity of the liver under the effect of sporofusarin resulted from damage of the membrane structures of the cell, and, primarily, of lysosomes.
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PMID:[The effect of sporofusarin on the cell membranes of isolated perfused liver]. 122 93

Protein from many sources show negative correlation between their biological values and the levels of urea in the blood or urine of rats or pigs. On the basis of the difference in protein quality between raw and heated soybeans, it would be predicted that there should be a higher level of urea in the blood and urine of rats fed raw soybean meal. In the present study, however, little or no difference in the levels of urea in the blood and urine of animals fed raw or autoclaved soybean meal could be demonstrated. It is postulated that the increased catabolism of the poor quality protein of raw soybeans may be masked by a concomitant depression of liver arginase activity and/or a decrease in the total quantity of amino acids available for catabolism because of lower digestibility of the raw soybean protein.
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PMID:Levels of urea in the blood and urine of rats fed raw and heated soybean meal. 124 8

Urea and other small amides cross the toad urinary bladder by a vasopressinsensitive pathway which is independent of osmotic water flow. Amide transport has characteristics of facilitated transport: saturation, mutual inhibition between amides, and selective depression by agents such as phloretin. The present studies were designed to distinguish among several types of transport including (1) movement through a fixed selective membrane channel and (2) movement via a mobile carrier. The former would be characterized by co-transport (acceleration of labeled amide flow in the direction of net flow of unlabeled amide), the latter by counter-transport (acceleration of labeled amide flow in the opposite direction). Mucosal to serosal (M leads to S) and serosal to mucosal (S leads to M) permeabilities of labeled amides were determined in paired bladders. Unlabeled methylurea, a particularly potent inhibitor of amide movement, was added to either the M or S bath, while osmotic water flow was eliminated by addition of ethylene glycol and ethanol could not be demonstrated. Methylurea did not alter water permeability or transmembrane electrical resistance. The demonstration of co-transport is consistent with the presence of ADH-sensitive amide-selective channels rather than a mobile carrier.
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PMID:Amide transport channels across toad urinary bladder. 125 4

Coccinia indica (Family: Cucurbitaceae, locally known as telakucha) leaves were extracted with 95% ethanol. Following evaporation of the solvents, the residue was suspended in distilled water. When this suspension was fed orally to male normal-fed and 48-hr starved rats, the blood glucose was lowered 21% (P less than 0.01) in normal-fed and 24% (P less than 0.001) in 48-hr starved animals respectively. Starvation had induced a 3-fold increase in the activity of glucose-6-phosphatase and this activity was depressed 19% (P less than 0.05) by extract feeding while basal activity of the enzyme in normal-fed rats remained unaffected. Consistent with the depression of glucose-6-phosphatase, urea cycle enzyme arginase was also depressed 21% (P less than 0.001) and 12% (P less than 0.01) in the liver of 48 hr-starved and normal-fed animals respectively. Unlike glucose-6-phosphatase, starvation induced levels of gluconeogenic enzymes alanine aminotransferase and aspartate aminotransferase were not affected by Coccinia extract. These results suggest that the hypoglycemic effect of C. indica is partly due to the repression of the key gluconeogenic enzyme glucose-6-phosphatase.
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PMID:Hypoglycemic effects of Coccinia indica: inhibition of key gluconeogenic enzyme, glucose-6-phosphatase. 133 43

Isolated hepatocytes from hypothyroid, euthyroid and hyperthyroid rats have been employed to investigate the relative importance of reducing-equivalent shuttles for the transfer of hydrogen between cytoplasm and mitochondria during simultaneous ureogenesis and gluconeogenesis. In cells from hypothyroid animals, a 58% depression of glucose formation and 68% reduction in ureogenesis were induced by n-butylmalonate, an inhibitor of the malate shuttle. A more reduced state of the cytoplasmic compartment and a substantial fall in the concentrations of pyruvate, aspartate, alanine and glutamate accompanied this inhibition. Preincubation of cells with n-butylmalonate yielded greater inhibitory effects than observed in the absence of preincubation. The inhibitory effects on gluconeogenesis and ureogenesis were less in cells from euthyroid rats and were very much reduced in the case of glucose synthesis and absent in the case of ureogenesis, in cells from hyperthyroid rats. It is inferred that both the malate-aspartate and alpha-glycerophosphate shuttles may function in the transfer of reducing equivalents from cytoplasm to mitochondria during ureogenesis in hepatocytes. The major inhibition by n-butylmalonate of glucose and urea synthesis in hepatocytes from hypothyroid rats is due to the diminished activity of the alpha-glycerophosphate shuttle in these cells. Moreover, it follows that the NADH arising from the cytoplasmic malate dehydrogenase-catalysed reaction is accessible to both the malate-aspartate shuttle and the alpha-glycerophosphate shuttle.
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PMID:Reducing-equivalent transfer to the mitochondria during gluconeogenesis and ureogenesis in hepatocytes from rats of different thyroid status. 135 45

A study is presented on the role of F0 and F1 subunits in oligomycin-sensitive H+ conduction and energy transfer reactions of bovine heart mitochondrial F0F1 H(+)-ATP synthase. Mild treatment with azodicarboxylic acid bis(dimethylamide) (diamide) enhanced oligomycin-sensitive H+ conduction in submitochondrial particles containing F1 attached to F0. This effect was associated with stimulation of the ATPase activity, with no effect on its inhibition by oligomycin, and depression of the 32Pi-ATP exchange. The stimulatory effect of diamide on H+ conduction decreased in particles from which F1 subunits were partially removed by urea. The stimulatory effect exerted by diamide in the submitochondrial particles with F1 attached to F0 was directly correlated with a decrease of the original electrophoretic bands of a subunit of F0 (F0I-PVP protein) and the gamma subunit of F1, with corresponding formation of their cross-linking product. In F0 liposomes, devoid of gamma subunit, diamide failed to stimulate H+ conduction and to cause disappearance of F0I-PVP protein, unless purified gamma subunit was added back. The addition to F0 liposomes of gamma subunit, but not that of alpha and beta subunits, caused per se inhibition of H+ conduction. It is concluded that F0I-PVP and gamma subunits are directly involved in the gate of the F0F1 H(+)-ATP synthase. Data are also presented indicating contribution to the gate of oligomycin-sensitivity conferral protein and of another protein subunit of F0, F6.
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PMID:Role of F0 and F1 subunits in the gating and coupling function of mitochondrial H(+)-ATP synthase. The effect of dithiol reagents. 138 61

Thirty-three cases of infective endocarditis presenting during a 6.5 year period to a district general hospital were analysed retrospectively. The annual incidence was 22 cases per million population. Twenty-two cases had pre-existing cardiac disease, mainly valvular disease-usually rheumatic (nine cases) and prosthetic valves (10 cases). Recognizable precipitants such as recent surgery were uncommon. Two cases presented after deliberate drug overdose possibly due to depression exacerbated by systemic disease. Symptoms were usually non-specific. All but two cases had murmurs and most were pyrexial. Splinter haemorrhages and clubbing were seen in about 20% of cases. Viridans-type streptococci were the commonest infecting organisms (14 cases). Staphylococcal infection (six cases) was confined to intravenous drug abusers and patients with prosthetic valves. Five cases were culture negative. Cardiac failure was present in 13 cases at presentation and developed in seven others during treatment. Acute valve replacement was necessary in eight cases, and late replacement in three. Renal impairment (plasma urea > 8 mmol/l and/or plasma creatinine > 120 mumol/l) occurred in 19 cases during the course of their illness. Embolic phenomena occurred in 12 patients and mostly involved the central nervous system. In the 8 fatal cases, the cause of death was cardiac failure in six, cerebrovascular accident in one, and myocardial infarction in one. Four of the six patients who subsequently died of cardiac failure had been referred for surgery. Both those who were not referred had coexisting medical problems. Factors associated with increased mortality were age, male sex, cardiac failure (P < 0.01), renal impairment (P < 0.05), and embolic phenomena (P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Infective endocarditis in a district general hospital. 143 86

This study compared the function of reduced grafts prepared in situ or ex vivo and transplanted immediately or after 4 hr of cold storage. Measurements of acid/base balance, plasma electrolytes, albumin, and urea showed no differences between groups. There was no difference between the increase and decline of plasma AST in recipients of grafts transplanted immediately after either ex vivo or in situ reduction; the increase in plasma AST of recipients of stored grafts was up to 10-fold and persisted until the end of the study at 7 days, with some decline. Plasma fibrinogen decreased intraoperatively but levels were restored within 24 hr in all groups; plasma prothrombin and partial thromboplastin times were not significantly disturbed. The patterns of decline and return of tissue adenine nucleotides were similar in all groups. While the regenerative response measured by tissue thymidine kinase and mitotic figures was not different between the groups, comparison with results from a group of partially hepatectomized animals showed a 3-4-fold depression in response in reduced liver grafts. The contributions of the effects of ischemia, flushing, and preservation to the depressed regenerative response of reduced liver grafts need to be determined. The present studies suggest however, that with regard to functional assessment, results are not affected either by ex vivo or in situ reduction of the graft, or by cold storage for 4 hr.
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PMID:Ex vivo versus in situ resection of segmental liver grafts in pigs--a comparison in immediate and four-hour-stored grafts. 158 63

Lipid peroxidation may contribute to the nephrotoxicity of cephaloridine, a beta-lactam antibiotic. Copper and Se may protect against free radical damage, and dietary Se deficiency potentiates cephaloridine nephrotoxicity. The objectives of this study were to further investigate potentiation of cephaloridine toxicity by Se deficiency and to determine whether Cu deficiency increases cephaloridine-induced injury. Weanling male Sprague-Dawley rats were fed adequate, Cu-deficient, Se-deficient, and Se and Cu-deficient diets for 4 wk and subsequently injected i.p. with cephaloridine (1200 mg/kg body wt) or saline. Nephrotoxic response to cephaloridine occurred, with increased plasma urea, kidney weight, excretion of urinary enzymes, and kidney lesions. Cephaloridine also increased plasma sorbitol dehydrogenase activity. Selenium deficiency depressed kidney glutathione peroxidase activity (78%) and potentiated cephaloridine nephrotoxicity. Copper deficiency did not increase cephaloridine nephrotoxicity; the small depression (13%) in kidney Cu,Zn-superoxide dismutase activity may not have been sufficient to impair antioxidant status. However, the marked depression in kidney glutathione peroxidase activity during Se deficiency may have impaired antioxidant status and enhanced cephaloridine-induced injury. In contrast to results in the kidney, neither Se deficiency nor Cu deficiency potentiated cephaloridine hepatotoxicity, as assessed by plasma SDH activity.
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PMID:Cephaloridine nephrotoxicity is potentiated by selenium deficiency but not copper deficiency in rats. 158 39


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