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Biomedical subjects

M Torres

Publications and source records attributed to M Torres.

At least 37 records · Page 2Linked to original sources
PubMed2000

[Quality of antihypertensive drug prescription in a health area].

OBJECTIVE: To find the compliance with previously established criteria on the quality of prescription of medication for hypertension. DESIGN: Retrospective and concurrent evaluation study of scientific and technical quality, with processing data, using as data source the clinical history. SETTING: Primary care teams in a Madrid Health Area. PARTICIPANTS: 873 clinical histories of hyper-intense patients in treatment with diuretics, beta-blockers, ACE inhibitors and/or calcium antagonists were chosen through systematic probabilistic sampling with a randomised start. MEASUREMENTS AND MAIN RESULTS: Data on age, sex, recording of treatment, linked pathologies and situations conditioning the choice of medicine were gathered. Information on the defined use criteria of the various pharmacological groups was also collected. 1145 drugs were used on 873 patients. Most common were the thiazide diuretics (36%), followed by ACE inhibitors (34.4%), calcium antagonists (21%) and beta-blockers (8.6%). 72% of the patients were undergoing one single therapy. 89.7% of the cases (95% CI, 87.43-91.59) had the treatment correctly recorded in the clinical record. Of the 721 hyperintense patients over 59 years old, 70.3% (95% CI, 66.81-73.60) fitted the defined criterion for use of diuretics. 48.7% fitted the ACE inhibitor criteria defined (CI, 43.71-53.78); 85.7% the beta-blocker criteria (CI, 76.85-91.69); and 58.7% the calcium antagonist criteria (95% CI, 52.17-64.9). CONCLUSIONS: The fit of the use of diuretics with the defined quality criterion is acceptable, while in the cases of ACE inhibitors and calcium antagonists the quality of prescription could be improved, while the use of beta-blockers is minimal.

Adult↗
PubMed2000

Perinatal lethality of microtubule-associated protein 1B-deficient mice expressing alternative isoforms of the protein at low levels.

Microtubule-associated protein 1B (MAP1B) has been implicated in axogenesis in cultured cells. To gain insight into the functions that MAP1B plays in vivo, we analyzed a strain of Map1B mutant mice generated by a gene trapping approach. Homozygous mice die on the first day after birth, probably due to a severe abnormal development of the nervous system. They present alterations in the structure of several brain regions. The normal Map1B gene yields different protein isoforms from alternatively spliced transcripts. The smaller isoforms were present in wild type, hetero-, and homozygous mice, but their expression was higher in the mutants than in the wild-type. Moreover, trace amounts of MAP1B protein were also observed in Map1B homozygous mutants, indicating an alternative splicing around the gene trap insertion. Thus, the Map1B gene trapped mutation reported in this work did not generated a null mutant, but a mouse with a drastic deficiency in MAP1B expression. Analyses of these mice indicate the presence of several neural defects and suggest the participation of MAP1B in neuronal migration.

Alternative Splicing↗
PubMed2000

Restriction-modification system differences in Helicobacter pylori are a barrier to interstrain plasmid transfer.

Helicobacter pylori cells are naturally competent for the uptake of both plasmid and chromosomal DNA. However, we demonstrate that there are strong barriers to transformation of H. pylori strains by plasmids derived from unrelated strains. We sought to determine the molecular mechanisms underlying these barriers. Transformation efficiency was assessed using pHP1, an Escherichia coli-H. pylori shuttle vector conferring kanamycin resistance. Transformation of 33 H. pylori strains was attempted with pHP1 purified from either E. coli or H. pylori, and was successfully introduced into only 11 strains. Digestion of H. pylori chromosomes with different restriction endonucleases (REs) showed that DNA methylation patterns vary substantially among strains. The strain most easily transformed, JP26, was found to have extremely low endogenous RE activity and to lack a restriction-modification (R-M) system, homologous to MboI, which is highly conserved among H. pylori strains. When we introduced this system to JP26, pHP1 from MboI.M+ JP26, but not from wild-type JP26, transformed MboI R-M+ JP26 and heterologous MboI R-M+ wild-type H. pylori strains. Parallel studies with pHP1 from dam+ and dam- E. coli strains confirmed these findings. These data indicate that the endogenous REs of H. pylori strains represent a critical barrier to interstrain plasmid transfer among H. pylori.

Chromobox Protein Homolog 5↗
PubMed2000

Nitric oxide-sensitive guanylyl cyclase activity inhibition through cyclic GMP-dependent dephosphorylation.

The soluble form of guanylyl cyclase (sGC) plays a pivotal role in the transduction of inter- and intracellular signals conveyed by nitric oxide. Here, a feedback inhibitory mechanism triggered by cyclic guanosine-3',5'-monophosphate (cGMP)-dependent protein kinase (PKG) activation is described. Preincubation of chromaffin cells with C-type natriuretic peptide, which increased cGMP levels and activated PKG, or with cGMP-permeant analogue (which also activates PKG), in the presence of a broad-spectrum phosphodiesterase inhibitor, resulted in a decrease in subsequent sodium nitroprusside (SNP)-dependent cGMP elevations. This inhibitory effect was mimicked by activating a protein phosphatase and counteracted by the selective PKG inhibitor KT-5823 and by different protein phosphatase inhibitors. Immunoprecipitation of sGC from cells submitted to different treatments followed by immunodetection with antiphosphoserine antibodies (clone 4A9) showed changes in phosphorylation levels of the beta subunit of sGC, and these changes correlated well with differences in SNP-elicited cGMP accumulations. Pretreatment of cells with several PKG inhibitors or protein phosphatase inhibitors produced an enhancement of SNP-stimulated cGMP rises without changing the SNP concentration required to produce half-maximal or maximal responses. Taken together, these results indicate that the catalytic activity of sGC is closely coupled to the phosphorylation state of its beta subunit and that the tonic activity of PKG or its stimulation regulates sGC activity through dephosphorylation of the beta subunit.

Animals↗
PubMed2000

Surgical aspects of dialysis in newborns and infants weighing less than ten kilograms.

PURPOSE: Renal failure occurs in children with moderate frequency. Surgical aspects of establishing and maintaining dialysis access in small infants are exceptionally challenging. The purpose of this review is to evaluate the authors' experience with dialysis access for infants less than 10 kg, particularly with respect to the surgical care required. METHODS: A retrospective review was conducted between 1991 and 1999 of all pediatric dialysis patients weighing 10 kg or less (n = 29). Age at start of dialysis, duration of dialysis, modes of dialysis, and complications specific to peritoneal (PD) and hemodialysis (HD) were examined. RESULTS: The mean age at start of dialysis was 10.4 months and continued for an average duration of 16.3 months. Seventy-two percent of all patients required both modes of dialysis. HD and PD duration averaged 7.8 and 10.5 months, respectively. Catheter durability was 3.1 and 4.5 months per catheter for HD and PD, respectively. There was no significant difference in complications when comparing HD and PD. Patients who weighed 5 to 10 kg had significantly longer PD catheter durability than patients 0 to 5 kg (P = .001). Forty-one percent of patients terminated dialysis after transplantation, whereas 24% died awaiting transplantation. CONCLUSION: Despite a large number of operations required, infants less than 10 kg can be bridged successfully, by surgical intervention and subsequent dialysis, to transplantation.

Body Weight↗
PubMed2000

Corpus callosotomy in Colombia and some reflections on care and research among the poor in developing countries.

The authors present the results of a series of corpus callosotomies (CCS) in 97 patients performed from 1989 to 1997 at the Hospital Neurologico of the Liga Colombiana Contra La Epilepsia, Cartagena, Colombia. This study demonstrates the feasibility of performing these procedures in the developing world and analyzes the outcome and cost of treatment. Patients with medically intractable secondarily generalized epilepsy, bilateral nonfocal epileptic electroencephalogram (EEG), and absence of progressive encephalopathy were accepted as candidates (patients aged 0-30 years; 62 children, 19 girls and 43 boys, with mean age at surgery of 7.9 years; 35 adults, 19 women and 16 men, with mean age at surgery of 25.8 years). Preoperatively, the mean seizure frequency was 12.1 per day, or 364 per month (range, 0.06-200 per day, 1.8-6000 per month). Before surgery, 40% of patients were classified with generalized tonic-clonic seizures of different etiologies, or cryptogenic seizures; 36% had mixed seizures; 19% had Lennox-Gastaut Syndrome; and 5% had West Syndrome. Usually, routine EEG, computed tomography, and clinical findings sufficed for the surgical decision. The standard microsurgical technique performed was an anterior two-thirds CCS by the same surgeon under general anesthesia. In five cases, an additional frontal lobe excision after electrocorticography and subdural electrode monitoring was carried out in the same session. The results were evaluated after a mean follow-up of 35 months (range, 12-28). Two thirds of patients became seizure-free or were left with none or some disabling seizures. AED medication was eased slightly after surgery. The complication rate was low. The patients underwent postoperative psychosocial studies and neuropsychological rehabilitation and showed tendencies toward improvement. The direct cost of CCS in U.S. dollars (US$) ranged between 3,137 and 3,995 depending on the preoperative studies. Thus, CCS is well suited for selected patients in developing countries. Thus far, implantation of a vagus nerve stimulator has exceeded our economic possibilities in treating similar patients. Some reflections on care and research among epilepsy patients in developing countries are discussed.

Adolescent↗
PubMed2000

New European instruments for treatment outcome research: reliability of the maudsley addiction profile and treatment perceptions questionnaire in Italy, Spain and Portugal.

This report describes the field testing of two recently developed instruments for treatment evaluation research - the Maudsley Addiction Profile (MAP) and the Treatment Perceptions Questionnaire (TPQ) - in Italy, Portugal and Spain. The MAP and TPQ have been developed in the United Kingdom as brief instruments which contain measures of high face validity for research applications with the adult psychoactive substance use disorder population. The present study assesses the application of these instruments in the continental European context and assesses the internal and test-retest reliabilities of the items. A total of 206 subjects participated in the study (124 subjects participated in the MAP test-retest study, and 95 clients completed the TPQ). Thirteen subjects completed both the MAP and the TPQ questionnaires. Results of the study indicated that the MAP can be administered to clients in 15 min or less. The internal and test-retest reliabilities of the MAP and TPQ are satisfactory. Both instruments are suitable for treatment evaluation and other relevant research purposes in the European Union.

Adult↗
PubMed2000

Opposing RA and FGF signals control proximodistal vertebrate limb development through regulation of Meis genes.

Vertebrate limbs develop in a temporal proximodistal sequence, with proximal regions specified and generated earlier than distal ones. Whereas considerable information is available on the mechanisms promoting limb growth, those involved in determining the proximodistal identity of limb parts remain largely unknown. We show here that retinoic acid (RA) is an upstream activator of the proximal determinant genes Meis1 and Meis2. RA promotes proximalization of limb cells and endogenous RA signaling is required to maintain the proximal Meis domain in the limb. RA synthesis and signaling range, which initially span the entire lateral plate mesoderm, become restricted to proximal limb domains by the apical ectodermal ridge (AER) activity following limb initiation. We identify fibroblast growth factor (FGF) as the main molecule responsible for this AER activity and propose a model integrating the role of FGF in limb cell proliferation, with a specific function in promoting distalization through inhibition of RA production and signaling.

Animals↗
PubMed2000

Sylvatic population of Triatoma infestans from the Bolivian Chaco: from field collection to characterization.

A sylvatic Triatoma infestans DM (dark morph) population detected in the Bolivian Chaco was characterized and compared with various domestic ones. The degree of differentiation of DM was clearly within the T. infestans intra-specific level. Nevertheless marked chromatic and morphometric differences as well as differences in antennal pattern, chromosome banding and randomly amplified polymorphic DNA support the hypothesis of a distinct population. Continuous exchange of insects between wild and domestic habitats seems unlikely in the Chaco.

Animals↗
PubMed1999

Function of the cytoskeleton in human neutrophils and methods for evaluation.

The cytoskeleton plays a critical role in the determination of cell shape and serves as a scaffold for critical cellular enzymes and adhesion molecules. It provides structural integrity for the cell and regulates the function of many biochemical events that are critical to cellular function. The microfilamentous cytoskeleton participates in force generation necessary for shape change and motion. In neutrophils and other motile cells, polymerization of actin likely drives extension of the lamellae and participates in force generation through interaction with myosin, by polymerization alone and by osmotic mechanisms. Here, we will focus on the microfilamentous cytoskeleton in the neutrophil and briefly review its function as well as some direct and indirect methods that have been used to asses its role in neutrophil function. The discussion will address general approaches and leaves the details of the methods to the references.

Animals↗