Biomedical subjects

R Marín

Publications and source records attributed to R Marín.

At least 37 records · Page 2Linked to original sources

PubMed2001

Preeclampsia and Na,K-ATPase activity of red blood cell ghosts from neonatal and maternal blood.

We determined Na,K-ATPase activity and cholesterol/phospholipid ratio of maternal and cord red blood cell ghosts from either normotensive or preeclamptic pregnant women. The Na,K-ATPase activity of the red cell ghosts from neonatal blood is significantly lower (25-32%) as compared with the ATPase activity of the maternal red cell ghosts, regardless of the presence or not of preeclampsia. This diminution in Na,K-ATPase activity of the neonatal red blood cell ghosts could be due to an increase in the cholesterol/phospholipid molar ratio of the membrane. The Na,K-ATPase activity of the red blood cell ghosts from pregnant women was unaffected by preeclampsia; however, fetal red blood cell ghosts from infants of preeclamptic mothers showed a significantly lower ATPase activity (20%) than fetal red blood cell ghosts from infants of normotensive mothers. A low Na,K-ATPase activity in the neonatal red blood cells from mothers with preeclampsia could be an indication of an important modification of the physiological role of this enzyme.

Cholesterol↗

PubMed2001

Comparative study of the calcium adenosine triphosphatase of basal membranes of human placental trophoblasts from normotensive and preeclamptic pregnant women.

The Ca-ATPase activity of plasma membranes from human trophoblast is diminished in about 50% in preeclamptic women, as compared to normotensive pregnant women. This diminution is not due to changes in the behavior of the enzyme towards the free calcium concentration, the pH or the temperature of the incubation medium. Neither does it appear to be due to the presence of some condensing factor in the membranes, since the apparent energies of activation for the two tested ranges of temperature (10-20 and 20-37 degrees C) are similar for both normotensive and preeclamptic patients. The possibility of a diminution in the turnover rate of the Ca-ATPase in the plasma membranes from the preeclamptic patients is considered.

Adult↗

PubMed2001

[Severe maternal complications associated with pre-eclampsia: an almost forgotten pathology?].

Pre-eclampsia is a pregnancy-specific hypertensive syndrome associated with significant morbidity and mortality in mother and baby. With the increasing understanding of the disease process, the number of complications, and the maternal and perinatal deaths have fallen over the last few decades in the developed countries. In other parts of the world, the rates of mortality and morbidity remain high. We present eight cases of pre-eclamptic women with severe complications (eclampsia, HELLP syndrome, acute pulmonary edema, acute renal failure...) that were treated at our hospital in only a year, when we had not seen these pathologies in the last nine years. There was fetal death in three of the cases, related to abruptio placentae. There were no maternal deaths, but four mothers needed to be transferred to the intensive care unit, and required life-support techniques. The causes of these new events remain unclear. Can they be due to increase in maternal age or to the high incidence of abruptio placentae? Or maybe can they occur only by chance? These women with pre-eclampsia and severe complications that can have potentially devastating consequences are not an easily identified group. We concluded that women with pregnancy hypertension must be carefully managed by expert physicians, particularly if they are more than 30-35 years old, overweight, with previous history of hypertension or nulliparous, in order to decrease these several complications.

Abruptio Placentae↗

PubMed2000

Fasciola hepatica: lithogenic capacity in experimentally infested rats and chemical determination of the main stone components.

A study was done of the possible association between the development of common bile-duct stones and the presence of worms in rats experimentally infected with Fasciola hepatica. A total of 157 rats were individually infected with 20 metacercariae, and another 40 animals served as controls. The rats were dissected at 100, 200, 300, and 400 days postinfection (p.i.). A significant association was observed between the observation of stones and the presence of F. hepatica adults. The global frequency of bile-duct lithiasis in the parasitized rats was 22%, with a significantly lower incidence being observed in the younger group (100 days p.i.). Different analytical techniques were used to determine the main stone components. Energy-dispersive X-ray microanalysis showed calcium to be the main component in all cases (82-94%). Scanning electron microscopy, nuclear magnetic resonance ([1H]- and [13C]-NMR), and mass spectrometry revealed the predominance of palmitic (C-16) and stearic (C-18) acid.

Animals↗

PubMed2000

Ca-ATPase of human syncytiotrophoblast basal plasma membranes.

In the present work, a Mg(2+)-dependent, Ca(2+)-stimulated ATPase activity was determined and characterized in purified preparations of syncytiotrophoblast basal (fetal facing) plasma membranes, and its characteristics were compared to those of the active Ca(2+)-transport already demonstrated in this tissue. Similar to the active Ca(2+)transport, the Ca-ATPase is Mg(2+)-dependent, is stimulated by calmodulin, and is inhibited by vanadate. The K(m) for Ca(2+)activation is 0.25+/- 0.02microM, a value near to that described for calcium active transport in this tissue. Consequently, the Ca-ATPase activity of human syncytiotrophoblast basal plasma membrane described in this paper could be responsible for the active extrusion of calcium from the syncytiotrophoblast toward the fetal circulation.

5'-Nucleotidase↗

PubMed2000

Long-term prognosis of hypertension in pregnancy.

OBJECTIVES: To assess the prevalence of subsequent hypertension in women with hypertensive pregnancies and evaluate it according to the subclassifications of hypertension in pregnancy. METHODS: A survey was carried out in 476 women with hypertensive pregnancies (cases) and 226 normotensive controls delivered between 1973 and 1991 in a tertiary-level teaching hospital. They were invited to participate by mail and 273 cases (57%) and 86 controls (38%) completed the analysis. Outcomes assessed were prevalences of hypertension, diabetes, and hypercholesterolemia, together with cardiovascular morbidity. RESULTS: Among responders, age and parity were similar in both groups although follow-up time was longer in controls. Subsequent hypertension was more frequent within cases. After excluding chronic and unclassifiable hypertension, the mean blood pressure was higher in all other forms of pregnancy hypertension (103 +/- 13 mm Hg versus 94 +/- 13 mm Hg, p < 0.001); long-term hypertension prevalence was 45% in cases and 14% in controls [odds ratio (OR) = 5.1; 95% confidence interval (95% CI) = 2.5-9.8; p < 0. 001]. There were no differences with respect to the prevalences of subsequent diabetes or hypercholesterolemia. Remote hypertension was more common following gestational hypertension (54%) than in preeclampsia (38%), eclampsia (14%), or normotensive cases (14%) (OR for gestational hypertension versus normotensives = 7.2; 95% CI = 3. 4-14.8, p < 0.001, and OR for preeclampsia versus normotensives = 3. 7; 95% CI = 1.7-7.9, p < 0.001). CONCLUSIONS: After an average of 13. 6 years since the index pregnancy, women with hypertensive pregnancies have an increased risk of subsequent hypertension. Gestational hypertension is the hypertensive disorder of pregnancy with the highest incidence of subsequent hypertension. Women with preeclampsia have a greater tendency to develop hypertension than women with normotensive pregnancies. By contrast, women with eclampsia do not.

Adult↗

PubMed2000

Ca-ATPase of human myometrium plasma membranes.

We determined and characterized the Mg2+-dependent, Ca2+-stimulated ATPase (Ca-ATPase) activity in cell plasma membranes from the myometrium of pregnant women, and compared these characteristics to those of the active Ca2+-transport already demonstrated in this tissue. Similarly to the Ca2+-transport system, the Ca2+-ATPase is Mg2+-dependent, stimulated by calmodulin, and inhibited by vanadate. The Km for Ca2+ activation is 0.40 microM, very similar to that found for active calcium transport, i.e. 0.25 microM. Consequently, this Ca2+-ATPase can be responsible for the active calcium transport across the plasma membranes of smooth muscle cells.

5'-Nucleotidase↗

PubMed1999

Toxicological assessment of recombinant xylanase X(22) in wine.

Toxicological evaluation of xylanase X(22) from Aspergillus nidulans expressed in a wine yeast strain was carried out. The safety of the X(22) intake was assessed by digestibility, bioinformatic, and mouse short-term repeated dosing studies, although X(22) shows resistance to proteolytic degradation in the gastrointestinal system, is a minority protein component (<0.5 10(-)(6) %) of the produced wine, and shows no significant amino acid sequence homology to any known food allergens. The 4-week oral toxicity study was performed in Swiss mice at a dose level of 0.01, 0.1, or 1 mg/kg/day (these dosages correlate to 8, 80, and 800 times, respectively, the enzyme amount contained in 250 mL of wine). Body weight, food and fluid intake, urinalysis, and hematology data were obtained. Postmortem examinations and histopathology by both light and electron microscopy were performed. According to the results of this study, no adverse effects were detected by oral administration of X(22).

Allergens↗

PubMed1998

Preeclampsia, lipid peroxidation, and calcium adenosine triphosphatase activity of red blood cell ghosts.

OBJECTIVE: We evaluated the effect of lipid peroxidation on the calcium adenosine triphosphatase activity of red blood cell ghosts from normotensive pregnant women and compared it with the adenosine triphosphatase activity and lipid peroxidation in preeclampsia. STUDY DESIGN: Ten nulliparous normotensive and 10 nulliparous preeclamptic pregnant women (38 to 39 weeks of gestation) were used as blood donors. Preeclampsia was diagnosed on the basis of blood pressure (>140/90 mm Hg) and proteinuria (>0.5 gm of urinary protein per day). Red blood cell ghosts were prepared for both groups and used for calcium adenosine triphosphatase activity and lipid peroxidation determinations. Control ghosts (normotensive) were irradiated with ultraviolet light for different lengths of time. RESULTS: Calcium adenosine triphosphatase activity of red blood cell ghosts from normotensive women is sensitive to lipid peroxidation. The lipid peroxidation of red blood cell ghosts from preeclamptic women is higher than that from normotensive women. CONCLUSION: The diminution of the calcium adenosine triphosphatase activity with preeclampsia could be explained by the sensitivity of this adenosine triphosphatase to lipid peroxidation.

Adult↗

PubMed1998

Ouabain-insensitive Na(+)-ATPase activity of Malpighian tubules from Rhodnius prolixus.

In the present paper, we show the existence of a furosemide-sensitive Na(+)-stimulated, Mg(2+)-dependent ATPase activity in cell lysates of Malpighian tubular cells from Rhodnius prolixus, which could be the biochemical expression of the Na(+)-pump. The main characteristics of this activity are: (1) K0.5 for Na+ = 1.49 +/- 0.18 mM, (2) Vmax = 2.8 +/- 0.1 nmol inorganic orthophosphate (Pi).mg prot-1.min-1, (3) it is fully abolished by 2 mM furosemide, (4)it is insensitive to ouabain concentrations up to 10(-2) M, (5) it is sensitive to the presence of vanadate in the incubation medium indicating it to be a P-type ATPase, and (6) it is stimulated by nanomolar concentrations of Ca2+ in the incubation medium.

Adenosine Triphosphatases↗

PubMed1998

[Hepatocellular carcinoma associated to porphyria cutanea tarda and hepatitis C virus infection without cirrhosis].

The molecular basis of porphyria cutanea tarda is defective activity of hepatic uroporphyrinogen decarboxylase. A common characteristic is liver dysfunction than goes from cirrhosis to hepatocellular carcinoma. A high prevalence of hepatitis C virus markers has been demonstrated. We study a patient with PCT and hepatitis C virus markers that finally develops to hepatocellular carcinoma without previous cirrhosis. Previous studies with association of PCT and hepatitis C virus markers, have found liver diseases ranging from cirrhosis to hepatocellular carcinoma. The importance of this study is the absence of cirrhosis.

Carcinoma, Hepatocellular↗

PubMed1998

[Clock drawing test: qualitative and quantitative evaluation methods].

INTRODUCTION: The interest about the Clock Drawing Test (CDT) is justified because the importance of praxic disorders and especially the constructive apraxias in demented patients. Generally, this kind of deficits or intellectual losses has been less studied than aphasisas and agnosias. Nevertheless, praxias are usually affected in demential processes, even in initial stages. OBJECTIVE: We try to determine if the CDT can be useful as an assessment tool for dementia. We have used two assessment systems of the clock drawing in order to select an useful and reliable method of correction. PATIENTS AND METHODS: The sample is made up of 35 subjects older than 60 years, they were administered the Mini Cognitive Examination (MCE) and the CDT. Patients with previous diagnosis of dementia, others with physical pathology without neurological affectation and, finally, subjects without any kind of pathology were included in order to get a wide rank of punctuations. We carried out a reliability analysis between two raters and the discriminant validity of the CDT compared to the Spanish adaptation of the Mini Mental Examination. RESULTS: We achieve a high reliability inter examiner rates. Quantitative criteria of both scales are more objective than qualitative ones, therefore, these last should be more operativized. CONCLUSIONS: The results obtained in this work suggest that the clock drawing allow a rapid evaluation of cognitive function as the presence of cognitive impairment.

Aged↗

PubMed1997

A family with a milder form of adult dominant polycystic kidney disease not linked to the PKD1 (16p) or PKD2 (4q) genes.

Autosomal dominant polycystic kidney disease (ADPKD) is a genetically heterogeneous disease. Most families show positive linkage to polymorphic markers around the PKD1 (16p13.3) or PKD2 (4q21-23) loci. The PKD1 and PKD2 genes have been cloned and mutations defined in a number of patients. Several clinical studies have described a milder phenotype for PKD2 patients. More recently, evidence for a third genetic locus has been found in one Portuguese, one French-Canadian, and one Italian family. We identified a Spanish family with negative linkage to the PKD1 and the PKD2 loci. This family showed a very mild clinical phenotype compared to the other forms of ADPKD, including the non-PKD1/non-PKD2 families previously described.

Adult↗

PubMed1996

[Shunt surgery versus disconnection in portal hypertension. A comparative study].

Controversy remains about the best treatment for patients with esophagogastric variceal bleeding. In spite of different therapeutic alternatives and recent progress, such as liver transplantation of TIPS, many patients will finally be treated by standard surgery. With the aim to know the results of surgery in shunting vs non-shunting procedures, we have analyzed a recent and consecutive series of 68 cirrhotics patients operated on for variceal hemorrhage. According to the surgical technique there were three groups: I) 30 patients underwent a total portacaval shunt; II) 18 cases with an azygosportal disconnection; III) 20 patients with a partial portacaval shunt (8-10 mm H-portacaval PTFE graft). All groups were homogeneous considering age, sex etiology, Child-Pugh grade and timing of surgery (elective vs urgent). The complications and mortality rates were similar for the three groups. The overall operative mortality was 10%, and 5% in selected cases (Child-Pugh A-B, non urgent cases). With a follow-up for I, II and III group of 47, 44 and 27 months respectively, chronic encephalopathy have been seen in 61%, 15% and 15% respectively (p < .05). No patient in group I has rebled, and only one case in the II and III groups had a recurrence of hemorrhage. The actuarial three years survival was 76%, 86% and 85% (p NS), and the five year survival was 41% vs 86% for the groups I and II respectively (p < .05). In conclusion, in selected cases, surgery gives excellent immediate and long term results. In patients with variceal bleeding and failure of first line treatments, such as sclerosis or pharmacology, the partial H-portacaval shunt and non-shunting procedures are good alternatives, with low incidence of rebleeding and chronic encephalopathy.

Adult↗

PubMed1995

Na,K-ATPase activity in red blood cells from patients with Chediak-Higashi syndrome.

Na,K-ATPase activity of red blood cells from Chediak-Higashi syndrome (CHS) patients and relatives (gene heterozygous) was determined and compared to that of control, healthy, individuals. The enzyme activity was found to be strongly diminished in the CHS patients and slightly lower in their relatives. This reduced activity was due to a lower turnover number of the Na, K-ATPase as well as a decreased number of pumps. The reduced enzyme activity observed in these patients could be the result of an abnormal cell membrane fluidity, and the lowered number of Na, K-pumps could be explained as a consequence of an altered or deficient cell machinery caused by the CHS gene.

Adolescent↗

PubMed1995

Ouabain-sensitive Na+,K(+)-ATPase in the plasma membrane of Leishmania mexicana.

The mechanism responsible for the regulation of intracellular Na+ and K+ concentrations in trypanosomatids is unknown. In higher eukaryotes a ouabain-sensitive Na+,K(+)-ATPase located in the plasma membrane is the main mechanism for the regulation of the intracellular concentrations of Na+ and K+, while in trypanosomatids there are conflicting evidences about the existence of this type of ATPase. By the use of a highly enriched plasma membrane fraction, we showed that an ouabain-sensitive Na+,K(+)-ATPase is present in L. mexicana. The affinity of the enzyme for Na+ and K+ is similar to that reported for the mammalian Na+,K(+)-ATPase, showing also the same kinetic parameters regarding the relative concentration of those cations that give the optimal activity. Vanadate (10 microM) fully inhibits the ATPase activity, suggesting that the enzyme belongs to the P-type family of ionic pumps. The enzyme is sensitive to ouabain and other cardiac glycosides. These cardiac glycosides do not show any appreciable effect on the higher Mg(2+)-ATPase activity present in the same preparation. By the use of [3H]ouabain, we also show in this report that the binding of the inhibitor to the enzyme was specific. Taken together, these results demonstrate that an ouabain-sensitive Na+,K(+)-ATPase is present in the plasma membrane of Leishmania mexicana. Therefore, this Na+,K(+)-ATPase should participate in the intracellular regulation of these cations in Leishmania.

Animals↗

PubMed1994

Comparative aspects of Na+/K+ pump-mediated uncoupled Na+ efflux in red blood cells and kidney proteoliposomes.

Ouabain-sensitive uncoupled Na+ efflux has been studied in human, pig, and rat red cells and in vesicles containing reconstituted kidney Na+/K+ pumps obtained from these same species. The red cells from the different species gave qualitatively similar results; the uncoupled Na+ efflux was 15-30% of the Na+/K+ exchange rate, and this flux was inhibited at 5 mM extracellular Na+ (Na+o). At higher levels of Na+o there was a monotonic increase in the Na+ efflux. As has previously been observed in human red cells, the uncoupled efflux from pig red cells consists of Na+ and anion cotransport, suggesting that anion cotransport may be a general characteristic of uncoupled Na+ efflux in red cells. The uncoupled Na+ efflux carried out by pig and rat kidney Na+/K+ pumps differs from the red cell activity in that it represents no more than 2-4% of the Na+/K+ exchange rate and that 5 mM Na+o does not inhibit this efflux. Furthermore, the efflux does not appear to be dependent on anion cotransport. Vesicles containing human kidney Na+/K+ pumps differ from vesicles derived from pig or rat kidneys in that the Na+ efflux is not inhibited or stimulated by Na+ present on the opposite side; it thus appears that the Na+,K(+)-ATPase in these vesicles may be incapable of Na+/Na+ exchange. These results indicate that the ligand and kinetic properties of the uncoupled Na+ efflux mode of red cells are markedly different from kidney-derived Na+/K+ pumps reconstituted into proteoliposomes. The basis for these differences may be inherent in the Na+/K+ pumps themselves or represent differences between the two types of preparations studied.

Animals↗

PubMed1994

Preeclampsia and calcium adenosine triphosphatase activity of red blood cell ghosts.

OBJECTIVE: The current work was undertaken to study the calcium adenosine triphosphatase activity of red blood cell membranes from pregnant women with preeclampsia. STUDY DESIGN: Six normotensive and six preeclamptic pregnant women at 38 to 39 weeks of gestation were studied. The diagnosis of preeclampsia was made on the basis of blood pressure (> 140/90 mm Hg), proteinuria (> 0.5 gm of urinary protein per day), or edema. Hemoglobin-free red blood cell ghosts were prepared from the heparinized blood samples and were used to determine the calcium adenosine triphosphatase activity. RESULTS: It was found that the calcium adenosine triphosphatase activity of preeclamptic women is diminished by about 50% compared with that of normotensive pregnant women. CONCLUSION: A diminution of the calcium adenosine triphosphatase activity of erythrocytes in preeclampsia might be an indication that the in vivo activity of the calcium pump of these cells is diminished, which could, in turn, drive the cells to increase their cytoplasmic free calcium concentration.

Adult↗