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Biomedical subjects

M Linares

Publications and source records attributed to M Linares.

At least 37 records · Page 2Linked to original sources
PubMed1997

Etiology of bloody diarrhea in Bolivian children: implications for empiric therapy. Bolivian Dysentery Study Group.

In Bolivia, few data are available to guide empiric therapy for bloody diarrhea. A study was conducted between December 1994 and April 1995 to identify organisms causing bloody diarrhea in Bolivian children. Rectal swabs from children <5 years old with bloody diarrhea were examined for Salmonella, Shigella, and Campylobacter organisms; fecal specimens were examined for Entamoeba histolytica. A bacterial pathogen was identified in specimens from 55 patients (41%). Shigella organisms were found in 39 specimens (29%); 37 isolates (95%) were resistant to ampicillin, 35 (90%) to trimethoprim-sulfamethoxazole, and 24 (62%) to chloramphenicol, but all were susceptible to nalidixic acid. Only 1 of 133 stool specimens contained E. histolytica trophozoites. Multidrug-resistant Shigella species are a frequent cause of bloody diarrhea in Bolivian children; E. histolytica is uncommon. Clinical predictors described in this study may help identify patients most likely to have Shigella infection. Laboratory surveillance is essential to monitor antimicrobial resistance and guide empiric treatment.

Animals↗
PubMed1995

Dapsone for refractory chronic idiopathic thrombocytopenic purpura.

Fifteen patients with refractory chronic idiopathic thrombocytopenic purpura (ITP) were treated with dapsone (100 mg/d) for 1-31 months. The overall response rate to dapsone was 40%. Five patients responded in 1 month and one patient in 2 months. No pretreatment characteristics--sex, age, platelet count or duration of ITP--were correlated with response to dapsone. Treatment was well tolerated. The most frequent adverse effect was dose-related haemolytic anaemia. In our experience, dapsone provides an inexpensive and well-tolerated alternative for patients with ITP who had inadequate responses to conventional therapy.

Adolescent↗
PubMed1995

Increased susceptibility of microcytic red blood cells to in vitro oxidative stress.

Oxidative damage to erythrocytes in thalassaemia has been related to generation of free radicals by an excess of denaturated alpha- or beta-globin chains, intracellular iron overload and low concentration of normal haemoglobin (HGB). Two good indicators of such oxidative damage are the high red blood cell (RBC) malonyldialdehyde (MDA) production detected following exogenous oxidant stress and the decrease of pyrimidine 5'-nucleotidase (P5N), the most sensitive enzyme to SH-group damage in vivo. Conflicting data, however, have so far accumulated in the literature concerning differences in oxidative damage between the different forms of thalassaemia and iron deficiency anaemia (IDA). In the present study, oxidative susceptibility, as defined by the production of MDA in vitro and antioxidant capacity, as measured by the activity of RBC glutathione peroxidase (GPx), superoxide dismutase (SOD) and by reduced glutathione (GSH), have been studied in microcytic RBCs from patients with beta-thalassaemia trait, Spanish (delta beta) zero-thalassaemia heterozygotes (delta beta-thalassaemia trait) and iron deficiency anaemia (IDA). The results are consistent with the existence of significant differences in the severity and pattern of oxidative stress susceptibility between beta-thalassaemia trait (increased MDA production and higher SOD and GPx activities) and the other two forms of microcytosis (delta beta thalassaemia trait and IDA). Furthermore, the finding of normal P5' N activity in delta beta thalassaemia trait, gives further support to the less intense peroxidative environment of RBCs in this form of thalassaemia when compared to beta-thalassaemia trait, characterized by acquired RBC P5' N deficiency due to oxidative damage.

5'-Nucleotidase↗
PubMed1995

Chronic idiopathic thrombocytopenic purpura in the elderly.

From a group of 118 patients with chronic idiopathic thrombocytopenic purpura (ITP), 43 were older than 60 years at diagnosis. In this report, we describe the clinical evolution and therapeutic response in young and old patients. The overal rate of hemorrhagic manifestations was similar in the two age groups, but a greater risk for severe bleeding was observed in elderly patients. There were no significant differences between old and young patients in response to steroids. In none of our patients was mortality associated with bleeding or side effects of the treatment. In conclusion, we have observed a more benign clinical course in elderly patients with chronic ITP as compared to previous reports.

Adolescent↗
PubMed1992

Low molecular weight heparin (CY-216) versus unfractionated heparin in chronic hemodialysis.

In 14 patients undergoing chronic hemodialysis, we investigated the safety and efficacy of the low molecular fragment (CY-216) in comparison to unfractionated heparin (UFH) in the prevention of clotting in the extracorporeal circuit (ECC). In this study, 168 hemodialysis sessions were undertaken with UFH in 2 bolus doses (5,437 +/- 1,477 SD IU) and 231 with CY-216 in a single bolus dose [initial dose 150 anti-Xa U Institut Choay (IC)/kg]. There were no clots in the bubble trap in any UFH sessions, and 14.8% had coagulated fibers in the dialyzer. Clotting in the bubble trap was observed in 2 CY-216 sessions (0.8%) and coagulated fibers in 22.6% of the sessions. At the end of the study, the mean dose of CY-216 was 250 anti-Xa UIC/kg but a dose of 350 anti-Xa UIC/kg was needed in the 2 patients treated by recombinant human erythropoietin. Anti-Xa levels at the end of the runs were higher (0.47 +/- 0.1 U/ml) in the CY-216 group than in the UFH group (0.28 +/- 0.1 U/ml). There was a correlation between anti-Xa levels and efficacy in the CY-216 group. An anti-Xa activity above 0.4 U/ml was needed in order to minimize thrombus formation. Antithrombin III-protease complexes (ATM) and D dimer fibrin derivatives (D dimer) were used as thrombotic markers but they were of little value for the detection of fibrin formation in the ECC. Our findings suggest that CY-216 administered as a single bolus dose seems to be of similar effectiveness to UFH.

Aged↗
PubMed1991

Heterozygous pyruvate kinase deficiency and severe hemolytic anemia in a pregnant woman with concomitant, glucose-6-phosphate dehydrogenase deficiency.

The aim of this paper is to describe the clinical and hematological characteristics of a 32-year-old woman with concomitant heterozygous pyruvate kinase (PK) and glucose-6-phosphate dehydrogenase (G6PD) deficiencies and severe hemolytic anemia during pregnancy. In 1964, Oski et al. described a family in which a clinically healthy woman was heterozygous for both PK and G6PD deficiencies. To our knowledge, the present case is the first described in which the same condition is associated with hemolysis. A heterozygous condition for both enzymopathies was clearly demonstrated by family study criteria, and all other causes of hemolytic anemia were eliminated. No evidence of genetic relationship between the two disorders was demonstrated. Since late onset of hemolysis in heterozygous PK-deficient women has been observed in association with pregnancy and the molecular characteristics of the concomitant deficient G6PD enzyme were kinetically favorable, partial PK deficiency is suggested as the major cause of hemolysis in this patient.

Adult↗
PubMed1991

Hepatocellular carcinoma and squamous cell carcinoma in a patient with Fanconi's anemia.

Acute leukemia, hepatocellular carcinoma, and squamous cell carcinoma have been reported in patients with Fanconi's anemia. We report on a 31-year-old woman who developed squamous cell carcinoma of the esophagus and hepatocellular carcinoma. Jaundice and hepatic tumor developed in 1981, after she had received oxymetholone for 10 years. Liver biopsy revealed peliosis hepatis. Androgenic therapy was stopped and the jaundice resolved. However, the hepatic tumor was observed to be unchanged. The patient died of disseminated squamous cell carcinoma, but no metastatic lesions from hepatocellular carcinoma were detected in the autopsy. The association of Fanconi's anemia and squamous cell carcinoma is reviewed, and the malignant potential of androgen-related hepatic tumors is discussed.

Adult↗