Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isosorbide dinitrate is an effective vasodilator that improves resting left ventricular performance in patients with congestive heart failure, but little is known of the effect of the drug on the response to exercise. Bicycle exercise to symptomatic maximum was performed by 18 patients with class II to IV congestive heart failure before and 90 minutes after administration of isosorbide dinitrate, 40 mg orally. Although resting pulmonary wedge pressure and systemic vascular resistance were significantly reduced after isosorbide dinitrate, exercise duration was not altered and maximal oxygen consumption was not significantly changed (13.6 +/- 1.3 [SEM] standard error of the mean versus 13.8 +/- 1.2 ml/kg per min). At peak exercise pulmonary wedge pressure of 37.1 +/- 1.7 mm Hg, cardiac index of 4.19 +/- 0.35 liters/min per m2, and systemic vascular resistance of 14.7 +/- 1.3 units were not significantly different after nitrate administration. However, at submaximal loads, pulmonary wedge pressure was reduced from 33.6 +/- 1.7 to 27.9 +/- 1.8 mm Hg (P less than 0.01), and systemic resistance from 16.5 +/- 1.5 to 13.7 +/- 1.0 units (P less than 0.01) after administration of isosorbide dinitrate. Thus, short-term administration of nitrates does not improve maximal exercise capacity or left ventricular performance at maximal exercise in patients with congestive heart failure, but it does appear to improve pump function at submaximal work loads and may therefore enable patients to perform limited exercise more comfortably.
 ...
PMID:Effect of isosorbide dinitrate on response to submaximal and maximal exercise in patients with congestive heart failure. 43 62

Previous studies of heavy metal salt-induced acute renal failure demonstrated abnormalities of fluid and solute transport by nephron segments and alterations in glomerular filtration rate and renal hemodynamics. To determine the direct effects of uranyl nitrate (UN) or HgCl2 on ion transport, their effects were studied on the isolated urinary bladder of the turtle. Unidirectional 24Na+ and 36Cl- fluxes were measured across short-circuited bladders. The addition of 0.1 mM UN to the mucosal solution resulted in a 69.9 +/- 4% (SEM) decrease in short-circuit current (SCC) without change in transepithelial resistance. Net Na+ flux (7.95 +/- 0.81 mueq/h per 8 cm2) decreased by the same magnitude as the SCC, primarily due to a 5.75 +/- 0.76 mueq/h per 8 cm2 decrease in the mucosal- (M) to-serosal (S) Na+ flux. Net Cl- flux decreased also primarily due to a decrease in M-to-S Cl- flux. Addition of 0.4 mM UN to S did not measurably affect the SCC or ion fluxes. The addition of 10 muM HgCl2 in another group of bladders reduced SCC and M-to-S Na+ flux by 81 +/- 7% without change in Cl- fluxes or resistance. The removal of either UN or HgCl2 from M by washing did not reverse the decreased SCC, but after washing addition of either dithiothreitol, 2 mM, or amphotericin B, 20 mug/ml, to M completely reversed the effects of UN or HgCl2 on SCC. These studies suggest that heavy metal salts inhibit Na+ transport by the turtle bladder without altering passive ion fluxes.
 ...
PMID:Heavy metal-induced alterations in ion transport by turtle urinary bladder. 93 49

UO22+ 1.3 mM added as UO2(NO3)2 to the mucosal solution consistently inhibited the P.D. and ISC evoked by 11 mM glucose and 35 mM 3-O-methyl glucose across isolated strips of bullfrog small intestine bathed by symmetrical Ringer solutions in which SO42- was the major anion. The average degree of inhibition in the presence of glucose was 42 +/- 7(SEM) percent. P.D. and ISC in the absence of transported solutes were not significatnly altered by mucosal UO22+ at this concentration. Increasing the mucosal UO22+ concentration to 2.6 mM did not significantly increase its inhibitory action on glucose-evoked P.D. and ISC. Further increasing the UO22+ concentration to 13 mM completely inhibited glucose-induced P.D. and ISC but also markedly reduced these parameters in the absence of glucose. Serosal UO22+ (1.3mM) had no effect on the P.D. and ISC evoked by glucose and 3-O-methyl glucose. It is suggested that the inhibitory action of UO22+ involves binding of this ion to anionic sites located in the apical membrane of the absorptive cells. Mucosal or serosal UO22+ (1.3 mM) had no effect on the P.D. and ISC elicited by 20 mM valine, indicating that under the conditions of these experiments UO22+ selectively inhibits sugar-induced P.D. and ISC and, by implication mucosal sugar uptake.
 ...
PMID:Sugar-induced potential difference and short circuit current in bullfrog small intestine: effect of UO22+. 108 34

The aim of this study was to compare the efficacy and safety of continuous and intermittent transdermal nitrate therapy using ambulatory electrocardiographic (Holter) monitoring. Eighty-five patients with stable angina pectoris and positive exercise test results participated during their concomitant antiischemic medication in a randomized open trial lasting 12 weeks. After a 3-week run-in period with continuous therapy (10 mg/24 hours), patients were randomized to either continuous- or intermittent-therapy groups. In the intermittent-therapy group the patients removed their patch at night (the mean patch-off period was 10 hours). Forty-eight-hour Holter monitoring was performed in each patient after randomization, and again after 2 and 12 weeks. Eighteen patients withdrew, 9 in each group. A total of 11,194 hours of electrocardiography were recorded and 607 ischemic episodes were detected, of which 79% were asymptomatic and 95% appeared during daytime. The number of ischemic episodes per 48 hours with intermittent therapy was 3.1 +/- 0.7 (mean +/- SEM) after randomization, 1.8 +/- 0.4 at 2 weeks and 2.0 +/- 0.6 at 12 weeks. With continuous therapy the respective numbers were 3.8 +/- 1.1, 3.5 +/- 0.9 and 4.2 +/- 1.2. The differences were not statistically significant because a large number of patients (30%) had no ischemic episodes on Holter recording. However, when examining 47 patients with episodes during the study, the number of episodes was significantly reduced in the intermittent-therapy group (p less than 0.05 at 12 weeks). The changes in asymptomatic and symptomatic episodes were concordant. No changes and differences between the treatment groups were seen in nighttime episodes.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Acute and long-term effects on myocardial ischemia of intermittent and continuous transdermal nitrate therapy in stable angina. 135 Aug 82

The objective of this study was to test the hypothesis that a degraded subsurface layer containing microcracks is produced in dental composites as a result of finishing procedures. Various composites in the form of rectangular bars were finished with a 12-fluted carbide bur or a fine diamond within minutes of light-curing, and were subsequently stained with silver nitrate. Microscopic evaluation revealed that significant penetration of stain occurred in the unfinished as well as in the finished surfaces. The extent of dye penetration that could be directly attributed to a damaged layer produced by the finishing procedure was less than 10 microns, being greatest for a microfill (Silux Plus) and a hybrid (P-50) composite. There was no difference between the effects of the finishing instruments. SEM analysis of the subsurface showed an absence of any cracks for the composites. However, occasional disruption of the interface between the pre-polymerized resin fillers and the matrix was apparent for the microfill material. The results showed that only a very limited subsurface damage may be created in certain composites during the initial contouring of a restoration.
 ...
PMID:Evaluation of subsurface defects created during the finishing of composites. 138 34

Beagles were exposed to aerosols of 239PuO2, 238PuO2, or 239Pu(NO3)4. Exponential growth constants for 50 primary lung tumors (23 bronchioloalveolar carcinomas, 22 papillary adenocarcinomas, 5 adenosquamous carcinomas) were calculated in 37 dogs, using sequential thoracic radiography. A wide range in doubling time (6 to 287 days) was observed. Mean +/- SEM doubling time was 93 +/- 10 days for bronchioloalveolar carcinoma, 107 +/- 13 days for papillary adenocarcinoma, and 101 +/- 36 days for adenosquamous carcinoma. Lung tumor growth rate in dogs was comparable to that in human patients with similar histologic tumor types. Linear regression analysis revealed significant (P < or = 0.0001) correlation between doubling time and survival of individual dogs. Doubling time was not significantly dependent on tumor type, sex, age at time of diagnosis, initial lung deposition, or isotope. Extrapolating time to tumor onset from tumor doubling time cannot be used to reliably predict the onset of malignancy.
 ...
PMID:Radiographically determined growth dynamics of primary lung tumors induced in dogs by inhalation of plutonium. 145 11

Transport systems involved in uptake and biliary secretion of bile salts have been extensively studied in rat liver; however, little is known about these systems in the human liver. In this study, we investigated taurocholate (TC) transport in canalicular and basolateral plasma membrane vesicles isolated from 15 human livers (donor age 6-64 yr). ATP stimulated the uptake of TC into both canalicular and basolateral human liver plasma membrane vesicles (cLPM and blLPM, respectively). Considerable interindividual variations in the transport velocity were observed in the different membrane preparations used: 9.0 +/- 1.3 (mean +/- SEM, n = 17; range 1.6-18.0) and 9.3 +/- 2.0 (range 1.1-29.8) pmol TC.mg protein-1.min-1 at 1.0 microM TC for cLPM and blLPM, respectively. TC transport was temperature sensitive and showed saturation kinetics with a high affinity for TC (Km 4.2 +/- 0.7 microM and 3.7 +/- 0.5 microM for cLPM and blLPM, respectively). Transport was dependent on the ATP concentration and saturable (Km 0.25 +/- 0.03 mM, n = 3). Neither nitrate, which reduces membrane potential, nor the protonophore FCCP strongly inhibited ATP-dependent TC transport, indicating that membrane potential and proton gradient are not involved in this process. TC transport was significantly inhibited by the classical anion transport inhibitor 4,4'-diisothiocyanostilbene-2,2'-disulfonate (250 microM) and the glutathione conjugate S-(2,4-dinitrophenyl)glutathione (100 microM). In conclusion, high affinity ATP-dependent TC transport is present in human liver at both the canalicular and the basolateral sides of the hepatocyte.
 ...
PMID:Adenosine triphosphate-dependent taurocholate transport in human liver plasma membranes. 146 89

It has been suggested that the endogenous nitrosation of aliphatic, cyclic and heterocyclic secondary amines in the urinary bladder of patients with chronic urinary bacterial infections and in the human stomach may provide an important additional source of exposure to carcinogenic volatile N-nitrosamines. The most commonly occurring nitrosatable secondary amines found in human saliva, gastric juice, blood, urine and faeces are dimethylamine (DMA), pyrrolidine (PYR) and piperidine (PIP). All of 40 analysed samples of gastric juice contained 0.87 +/- 0.89 (SEM) microgram/ml DMA, 39 contained 1.35 +/- 2.53 microgram/ml PIP, 36 contained 0.18 +/- 0.15 microgram/ml PYR and 14 contained 0.05 +/- 0.11 microgram/ml diethylamine. Nitrate (14.0 +/- 15.7 microgram/ml) was present in all samples and 11 of 40 samples contained 0.43 +/- 1.38 microgram/ml nitrite. Only one gastric juice sample with pH less than 4.5 contained nitrite (0.1 microgram/ml). In paraplegics, patients with bladder augmentations and two control groups without bacterial infections of the urinary bladder, a mean daily excretion of 40.5-49.7 mg/day DMA, 19.4-23.8 mg/day PYR and 26.1-31.7 mg/day PIP was found. In both patient groups suffering from chronic bacterial infection of the urinary bladder, the corresponding volatile N-nitrosamines were formed by endogenous nitrosation and excreted in urine.
 ...
PMID:Secondary amine precursors to nitrosamines in human saliva, gastric juice, blood, urine and faeces. 157 7

The potential role of platelet-activating factor (PAF)-acether and of IL-5 as an eosinophil-proliferating, activating, and/or recruiting mediator in asthma led us to study the effects of human (h) rIL-5 (hrIL-5) and PAF-acether, alone or combined, on isolated guinea pig eosinophils. Two populations of eosinophils were separated from peritoneal lavages of polymyxin B-treated guinea pigs upon a discontinuous metrizamide gradient: one of low density (between 20 and 22% of metrizamide, purity: 63 +/- 3%, n = 27) and another of normal density (between 22 and 24% of metrizamide, purity: 87 +/- 2%, n = 16). Chemotactic activity was evaluated on a micro-Boyden chamber, results being expressed as the number of migrating eosinophils (mean +/- SEM) at 40 microns through a cellulose nitrate filter (3 microns pore size) in the presence of the agonist or of the solvent alone. hrIL-5 dose-dependently stimulated normodense eosinophil chemotaxis, reaching a peak at 500 ng/ml (98 +/- 21 migrating eosinophils, n = 5, p less than 0.05). These eosinophils also responded to PAF-acether and to LTB4 and not to FMLP, hrTNF alpha, and LPS. Eosinophil preincubation with hrIL-5 increased significantly the migration by PAF-acether (173 +/- 23 migrating eosinophils with PAF-acether 10 nM after preincubation with hrIL-5 500 ng/ml vs 69 +/- 10 after preincubation with buffer alone, p less than 0.01) and failed to enhance migration by LTB4 or to uncover an activity for FMLP. Migration by PAF-acether was antagonized when the cells were preincubated with the antagonists BN 52021 and WEB 2086, which also inhibited migration by hrIL-5. Eosinophils were auto-desensitized by and to PAF-acether or LTB4, but were not cross-desensitized to each other. Eosinophils desensitized to PAF-acether failed to migrate with hrIL-5, but those desensitized to LTB4 responded to hrIL-5 as controls. hrIL-5 failed to induce the elevation of intracellular free calcium concentration and superoxide anion generation from basal values, whereas preincubation of eosinophils with hrIL-5 induced a significant increase in the rise in intracellular free calcium concentration and in superoxide anion generation by 10 nM PAF-acether but not by LTB4. In conclusion, the in vivo eosinophil migration in allergy may involve hrIL-5, particularly associated to PAF-acether.
 ...
PMID:Activation of guinea pig eosinophils by human recombinant IL-5. Selective priming to platelet-activating factor-acether and interference of its antagonists. 165 95

The presence of sulfhydryl (SH) groups appears to be fundamental to nitrate-induced vasodilation and N-acetylcysteine (NAC), a sulfhydryl (SH)-donor substance, potentiates hemodynamic responsiveness to nitrates. We investigated the effect of simultaneous administration of NAC and isosorbide dinitrate (ISDN) on development of nitrate tolerance. In a double-blind, randomized, placebo-controlled cross-over study, seven patients with stable angina pectoris were treated for two 8-day periods with ISDN (40 mg four times daily, q.i.d.) together with NAC (controlled release 600 mg q.i.d.) or matching placebo. Bicycle exercise tests were performed before treatment was started, 1 h after treatment was started, and at day 8. After 8-day treatment with ISDN + placebo, responses determined by exercise testing were diminished as compared with responses obtained during acute therapy and did not differ from baseline values, suggesting development of tolerance to ISDN. During treatment with ISDN + NAC, time to 1-mm ST depression was significantly prolonged (441 +/- 44 vs. 381 +/- 40 s, mean +/- SEM) and total ST segment depression significantly reduced (1.9 +/- 0.7 vs. 3.5 +/- 0.8 mm) as compared with baseline values. The reduction in ST segment depression was significantly more pronounced during ISDN + NAC (46%) as compared with ISDN + placebo (23%). Although exercise time and time to angina pectoris were unaffected. NAC augmented the antiischemic effects of ISDN as assessed by ECG. This finding may suggest that development of nitrate tolerance is modified by chronic oral high-dose NAC administration.
 ...
PMID:Continuous oral N-acetylcysteine treatment and development of nitrate tolerance in patients with stable angina pectoris. 171 11


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