PubMed Health⌕ Search

Biomedical subjects

R Marín

Publications and source records attributed to R Marín.

88 records · Page 5Linked to original sources
PubMed1982

Partial characterization of the ouabain-insensitive, Na+-stimulated ATPase activity of kidney basal-lateral plasma membranes.

The present paper characterizes the Na+-stimulated ATPase activity present in basal-lateral plasma membranes from guinea-pig kidney proximal tubular cells. These characteristics are compared with those of the (Na+ + K+)-stimulated ATPase activity, and they are: (A) Na+-ATPase activity: (1) requires Mg2+; (2) may be activated by mu molar quantities of Ca2+; (3) optimal ratio Mg:ATP = 5:1-2 and Ka for Mg:ATP = 3:0.60 mM; (4) Ka for Na+:8 mM; (5) does not require K+; (6) is only stimulated by Na+ and Li+ (in a lower extent); (7) is similarly stimulated by the Na+ salt of different anions; (8) hydrolyzes only ATP; (9) optimal temperature: 47 degrees C; (10) optimal pH: 6.9; (11) is ouabain insensitive; (12) is totally inhibited by 1.5 mM ethacrynic acid, 2 mM furosemide and 0.75 mM triflocin. (B) (Na+ + K+)-ATPase activity: (1) also requires Mg2+; (2) is inhibited by Ca2+; (3) optimal ratio Mg:ATP = 1.25:1 and Ka for Mg:ATP = 0.50: 0.40 mM; (4) Ka for Na+: 14 mM (data not shown); (5) needs K+ together with Na+; (6) K+ may be substituted by: Rb+ greater than NH+4 greater than Cs+; (7) is anion insensitive; (8) hydrolyzes mostly ATP and to a lesser extent GTP, ITP, UTP, ADP, CTP; (9) optimal temperature: 52 degrees C; (10) optimal pH: 7.2; (11) 100% inhibited by 1 mM ouabain; (12) 63% inhibited by 1.5 mM ethacrynic acid, 10% inhibited by 2 mM furosemide and insensitive to 0.75 mM triflocin.

Adenosine Triphosphatases↗
PubMed1982

Ouabain-insensitive Na+-stimulated ATPase activity of basolateral plasma membranes from guinea-pig kidney cortex cells. II. Effect of Ca2+.

The ouabain-insensitive, Mg2+-dependent, Na+-stimulated ATPase activity present in fresh basolateral plasma membranes from guinea-pig kidney cortex cells (prepared at pH 7.2) can be increased by the addition of micromolar concentrations of Ca2+ to the assay medium. The Ca2+ involved in this effect seems to be associated with the membranes in two different ways: as a labile component, which can be quickly and easily 'deactivated' by reducing the free Ca2+ concentration of the assay medium to values lower than 1 microM; and as a stable component, which can be 'deactivated' by preincubating the membranes for periods of 3-4 h with 2 mM EDTA or EGTA. Both components are easily activated by micromolar concentrations of Ca2+. The Ka of the system for Na+ is the same, 8 mM, whether only the stable component or both components, stable and labile, are working. In other words, the activating effect of Ca2+ on the Na+-stimulated ATPase is on the Vmax, and not on the Ka of the system for Na+. The activating effect of Ca2+ may be related to some conformational change produced by the interaction of this ion with the membranes, since it can also be obtained by resuspending the membranes at pH 7.8 or by ageing the preparations. Changes in the Ca2+ concentration may modulate the ouabain-insensitive, Na+-stimulated ATPase activity. This modulation could regulate the magnitude of the extrusion of Na+ accompanied by Cl- and water that these cells show, and to which the Na+-ATPase has been associated as being responsible for the energy supply of this mode of Na+ extrusion.

Animals↗
PubMedDate not supplied

Fuzzy logic in a patient supervision system.

A patient supervision system in progress for intensive and coronary care units, focused on patients with acute myocardial infarct is briefly described particularly regarding the role that fuzzy logic is playing in its design, and why this is so.

Artificial Intelligence↗
PubMedDate not supplied

[Stability of an oral liquid morphine formulation for pediatric use].

OBJECTIVE: The aim of this study the determination of the stability of an oral morphine hydrochloride solutions. METHOD: Determinations of a concentrated morphine solution of 4 mg/ml and the impact of two temperatures, 4 degrees C (refrigerator) and 25 degrees C (room) was analyzed via spectrophotometric measurements. RESULTS: Findings showed the high stability of the solutions at 4 degrees C, since no significant degradation was observed during the 30 days of the study, whereas at room temperature stability losses were hardly seen during the first 7 days, reaching 6.8% +/- 0.5% after 15 days. CONCLUSIONS: The tested morphine solution is stable at 4 degrees C during 30 days, but not at room temperature.

Child↗
PubMedDate not supplied

[A review of the clinical application of dyes in gastrointestinal chromoendoscopy, and their magistral formulation].

OBJECTIVE: To review the drug compounding of dyes employed in chromoendoscopy, and their clinical effectiveness. METHOD: A literature search in Medline, Cochrane Library, and Micromedex was carried out with the term chromoendoscopy as a keyword, and the search was then repeated for each dye found in association with the term endoscopy. A number of monographs, scientific journals, and references quoted in selected papers were also reviewed. Papers collected were then classified according to their methodology. RESULTS: Ninety-six references were found, their original article being recovered for only 57 of these - 13 clinical trials, 21 case series, and 11 reviews. References were found for 7 dyes. Main indications, evidence of effectiveness, administration route, and drug formulation are described for each dye. CONCLUSIONS: The number of papers involved is high, but their accessibility is limited. Evidence is overall scarce, but high in cases such as methylene blue for Barrett s esophagus, lugol in the detection of esophageal carcinoma, and indigo carmine for colonic hyperplastic polyp differentiation. Drug compounding is rather simple, but scarcely developed.

Coloring Agents↗
PubMedDate not supplied

[Preeclampsia and peripartum cardiomyopathy: infrequent association].

Peripartum cardiomyopathy (PPCM) is a rare form of congestive heart failure that affects women late in pregnancy or in the early puerperium. PPCM is a disorder of unknown etiology that can have potentially devastating consequences. Although the etiology of PPCM remains unclear, a number of risk factors for this disorder have been proposed. However, the disease can occurred in women without these risk factors. Preeclampsia is associated with PPCM. However, cardiomyopathy is an infrequent complication of preeclampsia. Treatment of PPCM is similar to that other types of congestive heart failure. The pregnancy outcome is uncertain. Probably it depends on whether ther heart size returns to normal. We present the case of a 38 years old woman, who developed in an 33rd week of gestation a PPCM. She had some risk factors (include preeclampsia) but had a favorable evolution with conventional treatment. The rarity of the syndrome, its potential consequences, and the probable association with preeclampsia, stimulated us to present this case.

Adult↗
PubMedDate not supplied

[Multivalent informatics application for studies of the nutritional status of the population. Assessment of food intake].

The aim of the study is the presentation and validation of a computer program, GRUNUMUR, designed for nutritional evaluation studies in great population groups, and to describe some of the results obtained after the application of this working tool. This program includes he following types of studies: a) dietary study; b) food habits study; c) anthropometric study and d) clinical study. The main advantage of GRUNUMUR is the possibility of being periodically actualized without any important software knowledge, and to be opened to the introduction of new data bases. The software program GRUNUMUR Is one more of the multiple programs described in the literature. However, once validated, this tool has the particularity of being developed after an important experience in the nutritional field and only with a scientific purpose. The result is a reliable tool, which facilitates nutrition research.

Adolescent↗
PubMedDate not supplied

[Effectiveness of venlafaxine in the treatment of alcohol dependence with comorbid depression].

INTRODUCTION: There are no conclusive data on the effectiveness of antidepressant drugs in the treatment of comorbid cases of alcohol dependence and depression. OBJECTIVES: To determine the effectiveness of venlafaxine on depression and on severity (need of treatment) of alcohol dependence and related problems. METHODS: Observational, open-label, multicenter, 24-week follow-up study. PATIENTS: 90 outpatients with diagnosis of alcohol dependence and associated major depression disorder (DSMIV criteria). OUTCOMES MEASURES: the Hamilton Rating Scale for Depression (HAM-D17), European Addiction Severity Index (EuropASI) and Clinical Global Impression, severity and improvement subscales, (CGI-S and CGI-I). Evaluations were performed at baseline and at weeks 2, 4, 8 and 24. RESULTS: Mean age 44.94+/-9.74 years; 73.3 % man. HAM-D17 mean scores significantly decreased from baseline (24.85+/-5.94) to week 24 (5.976+/-4.68) and at each of the follow-up visits vs previous visit (p < 0.0005). Significant decreases from baseline to week 24 were obtained in four areas of EuropASI: medical status (2.12+/-2.45 to 1.07+/-1.68), alcohol use (5.29+/-2.24 to 3.04+/-2.35), family/ social relationships (3.68+/-2.36 to 1.71+/-2.06) and psychiatric status (5.61+/-1.81 to 2.67+/-2.03). Tolerance was excellent or good in 76.7% of the patients. CONCLUSIONS: Venlafaxine demonstrated to be effective in the treatment of depressive alcoholic patients. Furthermore, it seems to be useful to decrease the severity of problems related with the alcohol use.

Adult↗
PubMedDate not supplied

Evaluation of organophosphorus pesticide residues in citrus fruits from the Valencian community (Spain).

Approximately 200 citrus samples from markets of the Valencian Community (Spain) were analyzed to establish their residue levels in 12 organophosphorus pesticide residues during the 1994-1995 campaign. The organophosphorus pesticides carbophenothion, chlorpyriphos, chlorfenvinphos, diazinon, ethion, fenitrothion, malathion, methidation, methylparathion, phosmet, quinalphos, and tetradifon were simultaneously extracted by matrix solid-phase dispersion and determined by gas chromatography-mass spectrometry using selected ion monitoring mode. A total of 32.25% contained pesticide residues and 6.9% exceeded the European Union Maximum Residue Levels (MRLs). The pesticides found in the samples with residues above MRLs were carbophenothion, ethion, methidathion, and methyl parathion. Lower level residues of these and the other pesticides studied (except diazinon) were frequently found. The estimated daily intake of the 12 organophosphorus pesticide residues during the studied period was 4.87 x 10(-4) mg/kg body weight/day. This value is lower than the provisional tolerances dairy intakes proposed by the Food and Agriculture Organization and the World Health Organization.

Chromatography, Gas↗
PubMedDate not supplied

[The evaluation of the hypertensive patient via self-measured blood pressure at home].

OBJECTIVE: Evidence currently exist that treatment, and therefore prognosis, of the hypertensive patient can be improved by complementing the clinic blood pressure (BP) measurements with measurements taken out of the health care setting. The goal of the study was to validate a standard procedure of home BP self-measurement in contrast with a non invasive ambulatory BP monitoring (ABPM). METHOD: This was a transversal and descriptive study set at the primary care level. 58 hypertensive patients with poor office control were instructed to self-measure their BP, with a previously verified digital sphygmomanometer, at home, 30 times for 10 days, and in the close 15 days an ABPM was taken for 24 hours. Reliability was determined comparing the degree of agreement between the different methods via the intraclass correlation coefficient (ICC) and the analysis of the individual differences. RESULTS: The self-measured BP and the ABPM do not differ significantly in systolic BP and only by 1.88 mmHg for the diastolic BP. The results taken in the office are significantly superior to those obtained by other methods -23 mmHg for the systolic BP and from 9 to 11 mmHg for the diastolic BP-. The ICC obtained comparing the results of the self-measured BP and ABPM are of 0.73 for systolic and 0.76 for the diastolic, whereas in the comparisons between office/self-measured, and office/ABPM the ICCs fluctuate from 0.23 to 0.50. The graphic analysis of individual differences allows the evaluation of the degree of reliability and the independence to the "white coat phenomenon". CONCLUSIONS: The BP self-measurement protocol that we present is a valid instrument, capable of confirming hypertension as well a suspicion of "white coat phenomenon" particularly when the availability of ABPM is scarce.

Adult↗