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Biomedical subjects

J Mercader

Publications and source records attributed to J Mercader.

At least 19 recordsLinked to original sources
PubMed2003

Population pharmacokinetics of high dose ibuprofen in cystic fibrosis.

AIMS: To evaluate ibuprofen population pharmacokinetics in a large series of data collected in children with cystic fibrosis (CF) treated with high doses of ibuprofen (59 patients; 2-18 years), and to identify the main causes responsible for the considerable interindividual variability in ibuprofen serum levels. METHODS: Blood samples were collected during routine clinical care; serum ibuprofen concentrations were determined by HPLC. Fitting of the concentration/time data to a one compartment kinetic population model was performed by a non-linear mixed effect regression method. RESULTS: Body weight, dose, and ibuprofen dosage form (lysinate salt or the free acid form), for elimination clearance (CL/F); and body weight, dose, and fasting status for the apparent distribution volume (Vd/F) proved to be the covariates with influence in the model. The four factors identified helped to explain part of the interindividual variability observed, but the remaining unexplained variability made therapeutic drug monitoring absolutely essential.

Administration, Oral↗
PubMed2001

Eight hundred-year-old human remains from the Ituri tropical forest, Democratic Republic of Congo: the rock shelter site of Matangai Turu Northwest.

Little is known about human prehistory in the central African lowland tropical forest due to a paucity of archaeological evidence. Here we report results from our archaeological investigations of a late Holocene site in the northeast Congo Basin, with emphasis on a single skeleton from the rock shelter site of Matangai Turu Northwest, in the Ituri Forest, Democratic Republic of Congo. The skeleton dates from approximately 810 BP (1235 calibrated AD) and is associated with Later Stone Age lithics, animal bone and shell remains from wild taxa, fruit endocarps from forest trees, phytoliths from tropical forest plants, Late Iron Age ceramics, and a single iron artifact. Phytolith analysis indicates that the habitat was dense tropical forest, without evidence of domesticated food.

Adult↗
PubMed2000

Long-term effects of ursodeoxycholic acid in primary biliary cirrhosis: results of a double-blind controlled multicentric trial. UDCA-Cooperative Group from the Spanish Association for the Study of the Liver.

BACKGROUND/AIM: The aim of this study was to assess the efficacy of ursodeoxycholic acid (UDCA) for primary biliary cirrhosis in a randomized, double-blind placebo-controlled trial. METHODS: Consecutive patients (n=192) were randomized to receive 14-16 mg UDCA/kg/day or placebo. Patients underwent a complete history, physical examination, liver chemistries, immunological determinations and liver biopsy at entry and at the end of the trial, which lasted for at least 2 years. Patients were seen every 3 months and the median follow-up was 3.4 years (range 0.3 to 6.1 years). RESULTS: Patients receiving UDCA (99) or placebo (93) were comparable with regard to age, sex, biochemical parameters and liver histology. UDCA treatment was associated with decreases in alkaline phosphatase, gammaglutamyl transferase, alanine aminotransferase, and cholesterol levels, effects which were conspicuous after 3 months of treatment and remained similar during the follow-up. During the study 31 patients (10 receiving UDCA and 21 placebo) discontinued the trial because of noncompliance (n=11), voluntary withdrawal (n=19) or adverse effects (n=1). Treatment failure (death or liver transplantation) was observed in 17 patients receiving UDCA and in 11 patients receiving placebo. Times to death or liver transplantation and to clinical complications were not significantly different in patients receiving UDCA or placebo. Histological analysis indicates that UDCA improved portal inflammation and prevented histological stage progression. By contrast, histological stage as well as ductular proliferation and ductopenia progressed in patients receiving placebo. CONCLUSIONS: Although UDCA treatment did not significantly affect time to death or liver transplantation and to clinical complications, the effects on both cholestasis and liver histology suggest that UDCA is safe and may be useful for preventing the progression of primary biliary cirrhosis.

Cholagogues and Choleretics↗
PubMed2000

[Anatomopathological and biochemical correlation of lesions produced by standard and irrigated 4 mm radiofrequency catheters].

INTRODUCTION AND OBJECTIVES: The influence on the size of radiofrequency lesions by cooling of the tip of the electrode remains unclear. Moreover, the possible effects of two different cooling systems, closed and open, have not been well differentiated. We designed this study to compare both systems of irrigated-tip catheters and the lesions produced with standard 4 mm catheters and also to evaluate the pathological and biochemical marker release correlation (cardiac troponin I) in an experimental model. METHODS: The study was performed in 20 pigs. Applying between 1-8 radiofrequency pulses, at a power of 15, 25 or 50 watts, for 15-60 seconds to each animal. After 7 days, the pigs were sacrificed for anatomopathological study. RESULTS: A total of 54 lesions were produced, 25 with standard catheters and 29 with irrigated catheters. The mean volume of the lesions produced with standard catheters was 146 +/- 110 microl and with irrigated-tip catheters 856 +/- 864 microl (p < 0.001). Peak values of cardiac troponin I were also higher for irrigated catheters (18 +/- 15 ng/ml) than for standard (6.5 +/- 3 ng/ml). The correlation between the size of the lesion and the levels of cardiac troponin I were 0.86 and 0.79 with the standard and irrigated-tip catheters, respectively. The incidence of cratering was higher with standard catheters (60%) than with irrigated (27%). CONCLUSIONS: The lesions produced with an irrigated catheter are greater than those observed with standard catheters. The mean peak value of postablation cardiac troponin demonstrate a good correlation with the real size of the necrosis.

Animals↗
PubMed1998

Metadoxine accelerates fatty liver recovery in alcoholic patients: results of a randomized double-blind, placebo-control trial. Spanish Group for the Study of Alcoholic Fatty Liver.

BACKGROUND/AIMS: Our aim was to investigate the effectiveness of metadoxine (pyridoxol L, 2 pyrrolidone-5-carboxylate) in the treatment of alcoholic fatty liver. METHODS: A double-blind randomized multicenter trial involving 136 chronic active alcoholic patients diagnosed with fatty liver by clinical, biochemical and ultrasonographic criteria was performed. Patients were treated with 1500 mg/day of metadoxine (n = 69) or placebo (n = 67) for 3 months. Patients were clinically and biochemically evaluated every month. Ultrasonography was performed before and after treatment. RESULTS: At the end of the study there was a significant improvement in the liver function tests in both groups. However, the changes were more rapid and greater in patients treated with metadoxine, in whom significant changes in serum levels of bilirubin, aminotransferases and gammaglutamyl transpeptidase were already observed after 1 month of treatment, and normalization of these parameters was observed at the end. After treatment, the percentage of patients with ultrasonographic signs of steatosis was significantly lower in the metadoxine group (28% vs 70%, p < 0.01) and the degree of steatosis was also lower in this group. Sixteen patients treated with metadoxine and 15 with placebo continued drinking. Alcohol intake was lower than initially, and similar in both groups. In the metadoxine group, the biochemical changes were similar in both the abstinent and the nonabstinent patients. In contrast, in the placebo group the improvement in the liver function tests was significantly higher in abstinents. Among patients who continued drinking, the prevalence (45% vs 92%, p < 0.05) and the degree of steatosis were also significantly lower in patients treated with metadoxine. CONCLUSIONS: In patients with alcoholic fatty liver, metadoxine accelerates the normalization of liver function tests and the ultrasonographic changes, even in those who do not completely abstain from alcohol intake. Thus, metadoxine could be useful in the treatment of the early stages of alcoholic liver disease.

Adult↗
PubMed1998

Cardiac troponin I and minor cardiac damage: biochemical markers in a clinical model of myocardial lesions.

Radiofrequency (RF) catheter ablation is the curative treatment of choice for many cardiac arrhythmias. After RF ablation there is always a small localized endomyocardial necrosis, necessary to abolish the arrhythmia. We designed this study to determine the serum concentrations of several cardiac markers in patients who underwent RF catheter ablation. The study shows a higher frequency of increase of serum cardiac troponin I (cTnI) than of creatine kinase (CK), the CK MB isoenzyme (CK-MB), or myoglobin. A pathological value of cTnI was found in 47 of 51 patients (92%) in the ablation group. The area under the ROC curve for cTnI was 0.9375, significantly higher than for the other biochemical markers (0.86, 0.76, and 0.75 for CK-MB, myoglobin, and CK, respectively), with P <0.05. We conclude that the serum concentration of cTnI is the best biochemical marker for detecting the minor myocardial damage produced by RF ablation.

Adult↗
PubMed1997

[The factors related to the research activities of primary care physicians].

OBJECTIVE: To find the factors related with the research activities of primary care (PC) doctors in Catalonia, especially their motivation and the obstacles to research perceived by the doctors themselves. DESIGN: An observational, crossover study. SETTING: Primary care doctors in Catalonia. PARTICIPANTS: The number of doctors (1,286) was divided into two: a) doctors who had published between 1989 and 1994 (n = 146), b) doctors who had not published. INTERVENTIONS: A survey concerning personal and workplace variables was carried out by post. RESULTS: The reply percentage was 49.5% (63.7% among those who had published and 44.85% among those who had not). The multivariant analysis showed a significant link between publishing and postgraduate residence training (MIR), the fact of working in a teaching centre and working in a centre with more than ten doctors. CONCLUSIONS: Research is close related to postgraduate residence training (MIR), work in a teaching unit and PC centres with over ten doctors. Care load, lack of time and difficulty in getting financing were the main obstacles to research given by the doctors polled.

Adult↗
PubMed1996

Nucleoside uptake in rat liver parenchymal cells.

Rat liver parenchymal cells express Na(+)-dependent and Na(+)- independent nucleoside transport activity. The Na(+)-dependent component shows kinetic properties and substrate specificity similar to those reported for plasma membrane vesicles [Ruiz-Montasell, Casado, Felipe and Pastor-Anglada (1992) J. Membr. Biol. 128, 227-233]. This transport activity shows apparent K(m) values for uridine in the range 8-13 microM and a Vmax of 246 pmol of uridine per 3 min per 10(5) cells. Most nucleosides, including the analogue formycin B, cis-inhibit Na(+)-dependent uridine transport, although thymidine and cytidine are poor inhibitors. Inosine and adenosine inhibit Na(+)-dependent uridine uptake in a dose-dependent manner, reaching total inhibition. Guanosine also inhibits Na(+)-dependent uridine uptake, although there is some residual transport activity (35% of the control values) that is resistant to high concentrations of guanosine but may be inhibited by low concentrations of adenosine. The transport activity that is inhibited by high concentrations of thymidine is similar to the guanosine-resistant fraction. These observations are consistent with the presence of at least two Na(+)-dependent transport systems. Na(+)-dependent uridine uptake is sensitive to N-ethylmaleimide treatment, but Na(+)-independent transport is not. Nitrobenzylthioinosine (NBTI) stimulates Na(+)-dependent uridine uptake. The NBTI effect involves a change in Vmax, it is rapid, dose-dependent, does not need preincubation and can be abolished by depleting the Na+ transmembrane electrochemical gradient. Na(+)-independent uridine transport seems to be insensitive to NBTI. Under the same experimental conditions, NBTI effectively blocks most of the Na(+)-independent uridine uptake in hepatoma cells. Thus the stimulatory effect of NBTI on the concentrative nucleoside transporter of liver parenchymal cells cannot be explained by inhibition of nucleoside efflux.

Affinity Labels↗
PubMed1996

Hormonal regulation of concentrative nucleoside transport in liver parenchymal cells.

Na(+)-dependent uridine uptake is stimulated in isolated rat liver parenchymal cells by glucagon. This effect is transient, reaches maximum levels of stimulation 10 min after hormone addition, and is dose-dependent. Glucagon action can be mimicked by agents that are able to hyperpolarize the plasma membrane (e.g. monensin) and by dibutyryl cyclic AMP. The effects triggered by glucagon, monensin and dibutyryl cyclic AMP are not additive, suggesting a common mechanism of action. 8-(4-Chloro-phenylthio)adenosine 3':5'-cyclic monophosphate (PCT), a cyclic AMP analogue but also a nucleoside analogue, markedly stimulates Na(+)-dependent uridine uptake in an additive manner to that triggered by monensin, similarly to the effect described for nitrobenzylthioinosine. Considering the roles reported for nucleosides in liver metabolism, the use of PCT as a cyclic AMP analogue should be precluded. Insulin is also about to up-regulate Na(+)-dependent uridine uptake by a mechanism which involves a stable induction of this transport activity at the plasma-membrane level. This is consistent with a mechanism involving synthesis and insertion of more carriers into the plasma membrane. It is concluded that the recently characterized hepatic concentrative nucleoside transporter is under short-term hormonal regulation by glucagon, through mechanisms which involve membrane hyperpolarization, and under long-term control by insulin. This is the first report showing hormonal modulation of the hepatic concentrative nucleoside transporter.

Animals↗
PubMed1989

Use of ceftriaxone in the treatment of bacterial infections in cirrhotic patients.

Sixty-two episodes of bacterial infection were studied in 51 cirrhotic patients. 2 g of ceftriaxone (active ingredient of Rocephin) were given intravenously once daily for 7-10 days. The infections were pneumonia, bacteremia, spontaneous bacterial peritonitis, urinary infection and others. Good responses were seen in 90% of the cases.

Adult↗
PubMed1984

Lymphangioma of the duodenum.

A case of lymphangioma of the duodenum is reported, and the literature pertinent to its pathology reviewed. This is the eleventh case reported, and the third in which the diagnosis has been made by endoscopy. The clinical and histological characteristics are important, on account of its presentation and its penetrating character into the neighbouring structures. The characteristics of this tumor seen during endoscopy are discussed.

Duodenal Neoplasms↗
PubMed1981

[Familial incidence of bird-breeder's lung and HLA (author's transl)].

The cases of two siblings affected with bird-breeder's lung are reported. The analysis of their HLA group demonstrated that both belonged to the haplotype HLA Bw15. The finding of a familial incidence of this type of alveolitis favors the presence of a genetic susceptibility for the disease. The same HLA group has been found in the rare families heretofore reported with bird-breeder's lung. Given that the pathogenesis of extrinsic allergic alveolitis has recently been linked to cellular immunity (T cells), and that the presence of a common HLA haplotype in patients suffering from bird-breeder's lung is related to the capacity for an immune response in general, and to the cellular immune response in particular, the presence of a genetic susceptibility in this disease appears as very likely, although the influence of other factors can not be ruled out.

Alveolitis, Extrinsic Allergic↗