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)

Previous studies on the regulation of responses of neutrophils to fMet-Leu-Phe have demonstrated the relevance of the role of the rate of occupation of the receptors by the stimulant. When this rate is decreased by presenting the peptide to neutrophils over a period of time by means of an infusion pump, the activation of the respiratory burst and of the secretion is greatly depressed or is absent. This paper deals with further investigations on the mechanisms of this desensitization, which previous results have shown to consist of an uncoupling between the ligand-receptor complexes and the target for cell responses, caused by the deceleration of the initial rate of occupation of the receptors. The data presented here demonstrate that this desensitization is not linked to the formation of a negative intermediate such as cAMP, but is associated with: (i) a depression of the rate and magnitude of the phosphatidylinositol response (activation of phosphatidylinositol turnover measured as modification of incorporation of [32P]Pi and [3H]glycerol into phosphatidylinositol and phosphatidic acid); (ii) a deceleration of the rate of the release of bound Ca2+, without a decrease in the total quantity of Ca2+ liberated (measured as fluorescence changes of chlorotetracycline treated neutrophils); (iii) a slower rise of cytosolic free Ca2+ concentration [Ca2+]i, without a decrease in the magnitude of the final increase of [Ca2+]i (monitored with Quin 2). These findings, which are discussed in relation to the recent hypotheses on the transduction reactions of receptor-mediated stimuli for neutrophil responses, are consistent with a mechanism of desensitization involving decreased production of diacylglycerol by the hydrolysis of phosphatidylinositol and deficient activation of Ca2+-phospholipid-dependent protein kinase C.
 ...
PMID:Mechanism of desensitization of neutrophil response to N-formylmethionylleucylphenylalanine by slow rate of receptor occupancy. Studies on changes in Ca2+ concentration and phosphatidylinositol turnover. 298 66

In order to demonstrate pharmacokinetic and pharmacodynamic interactions between fentanyl and buprenorphine, 3 groups of patients (n = 30) were compared, receiving either fentanyl (0.005 mg/kg b.w.) or buprenorphine (0.01 mg/kg b.w.) or both opioids as analgesic during surgery for disc protrusion. For a period of 4 h haemodynamic parameters were monitored and blood samples were taken for determination of the following concentrations: ADH, ACTH, cortisol, glucose, unbound glycerol, fentanyl and buprenorphine. Blood gas analyses were performed up to 2 h postoperatively. Although in all groups haemodynamic parameters were constant, there was an increase in factors related to operative stress (cortisol, glucose, unbound glycerol, postoperative acidosis) after the combination of both opioids, while postoperative ventilatory parameters in this group were not improved by the partial agonist buprenorphine. Plasma levels were not affected by combined application, except for a slight elevation of buprenorphine concentrations during additional use of fentanyl. Buprenorphine, at least in higher dosages, seems to antagonize analgesia induced by fentanyl, although respiratory depression is even more pronounced. It may be assumed, that with partial agonists the relation of agonistic and antagonistic activity may be different, depending on the dosage used and on the respective pharmacologic effect observed during investigation.
 ...
PMID:[Intra- and postoperative interactions between the 2 opioids fentanyl and buprenorphine]. 301 44

The effect of eicosapentaenoic acid (EPA) on natural killer (NK) cell activity of human lymphocytes was examined. The addition of an emulsion of trieicosapentaenoyl-glycerol (EPA-TG) emulsified with purified phosphatidylcholine from krill to a cytotoxicity assay system resulted in a marked depression of NK activity. The inhibition was proportional to the concentration of EPA-TG emulsion, and was observed as early as the first one hour of incubation at various effector to target cell ratios. Pretreatment of effector cells with EPA-TG emulsion resulted in significant suppression of their NK activity. Inhibition of cytotoxicity was not due to direct toxicity to effector cells or decreased target cell binding. These results indicate that EPA is a potent inhibitor of NK activity in vitro.
 ...
PMID:Inhibition of natural killer cell activity of human lymphocytes by eicosapentaenoic acid. 301 30

The purpose of this study was to determine whether the energy metabolism of an experimental rodent sarcoma was selectively depressed by the combination of inhibition of glycolysis and respiration. In vivo phosphorus-31 nuclear magnetic resonance spectroscopy was used to monitor the response of tumor or brain high-energy phosphate compounds to insulin hypoglycemia, rhodamine 123, or both agents in fasting rats with subcutaneous methylcholanthrene-induced sarcomas. Insulin or rhodamine 123 alone produced a similar 50% to 60% reduction in tumor adenosine triphosphate (ATP) concentration compared with controls injected with saline solution (p less than 0.05, one-way analysis of variance [ANOVA]). The combination of insulin plus rhodamine 123 resulted in a 90% reduction of tumor ATP concentration, which was significantly different from the effect of either agent alone (p less than 0.05, one-way ANOVA). Brain phosphocreatine and ATP concentrations were unchanged by these agents. Administration of dimethyl sulfoxide (DMSO)/glycerol, the vehicle for rhodamine, produced a 35% reduction of tumor ATP, which was similar to the effect of insulin alone but significantly different from rhodamine. The combination of DMSO/glycerol plus insulin hypoglycemia resulted in a 70% reduction in tumor ATP, which was significantly elevated compared with the combination of rhodamine plus insulin. Glucose deprivation induced by insulin, and combined with the inhibition of oxidative phosphorylation, produces an additive depression of tumor energetics. The drug vehicle DMSO/glycerol significantly depresses tumor energy metabolism, presumably because of its DMSO component, which may explain the previously reported antineoplastic efficacy of this solvent. Combinations of inhibitors directed at different points of tumor metabolism produced an enhanced depression of tumor energetics, whereas host tissue was protected.
 ...
PMID:Inhibition of tumor high-energy phosphate metabolism by insulin combined with rhodamine 123. 304 41

This investigation was performed to determine whether chronic ethanol feeding affects adipose tissue lipogenesis and glucose metabolism. Female Wistar rats were pair-fed nutritionally adequate liquid diets containing ethanol as 36% of energy or an isocaloric amount of carbohydrate for 3 weeks. Chronic ethanol feeding resulted in a depression of adipose tissue lipogenesis as assessed by labeled glucose incorporation into glyceride glycerol and glyceride fatty acids. Glucose oxidation was also impaired after chronic ethanol feeding. Such changes may contribute to the postprandial hypertriacyglyceridemia observed in alcoholics.
 ...
PMID:Decrease in lipogenesis and glucose oxidation of rat adipose tissue after chronic ethanol feeding. 308 66

Twelve trained males, in a fed state, were studied to examine the effect of pre-exercise fructose ingestion on endurance capacity during prolonged cycling exercise. Sixty minutes prior to exercise, subjects ingested either 60 or 85 g fructose or a sweet placebo. Mean exercise intensity initially required 62% of the maximal aerobic power and thereafter increased to elicit 72 and 81% of maximal aerobic power at 90 and 120 min of exercise, respectively. Exercise time (mean +/- SE) to exhaustion was significantly increased after fructose ingestion, as compared to placebo ingestion (145 +/- 4 vs 132 +/- 3 min, P less than 0.01). During the exercise, no differences were observed between both trials for oxygen uptake, heart rate, or perceived exertion. Serum glucose and insulin levels between both trials were not significantly different throughout the experiment. There were also no significant differences in serum-free fatty acids and glycerol levels as well as respiratory exchange ratio between fructose and placebo trials during the exercise. The results suggest that fructose ingestion is of benefit before prolonged exercise, because it provides a carbohydrate source to contracting muscles without transient hypoglycemia and a depression of fat utilization, and thereby delays the fatigue.
 ...
PMID:Effect of pre-exercise fructose ingestion on endurance performance in fed men. 328 17

Action potential fatigue has been studied in single short toe muscle fibres of Xenopus under three different conditions: in rested fibres which produced maximum tension, in fibres during post-contractile depression (PCD), a state of depressed tension generation but seemingly normal membrane properties, and in fibres de-tubulated by glycerol treatment. The fibres were stimulated continuously at 70 Hz (22.5 degrees C) and membrane potential was measured throughout the stimulation period with an intracellular microelectrode. Rested and PCD fibres exhibited similarities in the development of action potential fatigue during a 30 s stimulation period; the amplitude was reduced by 86 and 70 mV, respectively, and the duration, measured at a level of one-third of the peak amplitude, was increased from 1.1 to 4.2 and 1.3 to 3.7 ms, respectively. De-tubulated fibres were more resistant to action potential fatigue; the amplitude decreased by only 20 and 35 mV during 30 and 60 s of stimulation, respectively, and the duration was increased from 1.1 to 2.7 ms. It is concluded that action potential fatigue in skeletal muscle fibres is primarily caused by failing regenerative activity in the t-tubules, which is reflected in an altered shape of conventionally recorded action potentials.
 ...
PMID:Action potential fatigue in single skeletal muscle fibres of Xenopus. 357 17

The feasibility of modifying bovine cryopreservation methods for use with baboon embryos was evaluated. Twenty-six baboon embryos at the eight-cell to blastocyst stage of development were transferred after being frozen using glycerol as cryoprotectant. Either a two-step fast of a controlled linear temperature depression was achieved to -40 degrees C, followed by plunging into liquid nitrogen. After thawing, embryos were rehydrated in medium containing sucrose (0.5 to 1.0 M) using various methods of glycerol dilution. Embryos were transferred nonsurgically to anesthetized recipient baboons. Two term pregnancies resulted from six embryos frozen using the controlled linear cooling method and rehydrated by dropwise dilution of the sucrose (0.8 M) medium. Later cell stages had a greater morphological integrity postthaw than did earlier developmental stages, and embryos frozen by the linear cooling-rate method had less cell damage than those frozen by the fast method.
 ...
PMID:Cryopreservation and transfer of baboon embryos. 395 66

In the bovine lens the gamma IV-crystallin fraction is a principal determinant of the phase separation and opacification temperature, Tc (Siezen et al, Proc. Natl. Acad. Sci. USA 82, 1985, 1701). We have now measured the effect on Tc of purified gamma IV-crystallin solutions produced by a variety of reagents which affect protein-protein, protein-water and water-water interactions. Ionic strengths less than physiological increase Tc dramatically, while higher ionic strength has very little effect. Calcium ion concentrations up to 8 mM produce no change in Tc. Glycerol and acrylamide both depress Tc linearly with reagent concentrations; Tc depression of gamma IV-crystallin by these compounds is quantitatively the same as for whole lens. Sulfhydryl reducing agents such as glutathione and dithiothreitol lower Tc, while hydrogen peroxide increases Tc. Changes in opacification temperature of gamma IV-crystallin produced by oxidizing and reducing agents are time-dependent and highly non-linear with reagent concentration. Our results clearly show that bovine gamma IV-crystallin is an important target protein for various reagents which are known perturbants of the opacification temperature of whole lens. The relevance of these findings to human diabetic and senile cataract formation is discussed.
 ...
PMID:Controlled modulation of the phase separation and opacification temperature of purified bovine gamma IV-crystallin. 406 30

Administration of glucose, fructose, and glycerol to fasted rats produced a significant depression of liver phosphoenolpyruvate carboxykinase activity within 4 to 8 hours; galactose and ribose were much less effective. All the compounds yielded appreciable quantities of liver glycogen. The depression of phosphoenolpyruvate carboxykinase activity by glucose and glycerol was diminished by the concomitant administration of 2-deoxyglucose. The latter depressed glycogen formation from administered carbohydrate in muscle but not in liver. In rats made diabetic by alloxan, depression of elevated phosphoenolpyruvate carboxykinase activity by insulin was dependent upon a dietary source of carbohydrate. These results were interpreted to indicate that depression of certain gluconeogenic enzymes after carbohydrate ingestion is initiated by the metabolism of carbohydrate in some extrahepatic site.
 ...
PMID:Carbohydrate supply as a regulator of rat liver phosphoenolpyruvate carboxykinase activity. 416 92


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>