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Biomedical subjects

C Duran

Publications and source records attributed to C Duran.

51 records · Page 3Linked to original sources

Caffeine pharmacokinetics in preterm infants older than 2 weeks.

We studied 17 preterm infants receiving caffeine, and measured their plasma levels of caffeine and the theophylline metabolite by high-pressure liquid chromatography. The half-life was calculated by computer analysis using the least-square method. The mean gestational age of our patients was 29.7 +/- 1.9 weeks (mean +/- SD) and they were studied at 20.7 +/- 6.6 days (mean +/- SD) postnatal age. The caffeine half-life was 52.03 +/- 23.87 h (means +/- SD) and the theophylline half-life was 77.04 +/- 65.01 h (mean +/- SD).

Caffeine↗

HLA antigens in the Uitoto Indians and an urban population of Colombia.

One hundred individuals from the city of Bogota and 32 Uitoto Indians from the Colombian Amazonia were HLA-typed. The results showed that the two populations differ significantly in the frequencies of the alleles A28, B15, B39, Bw51, Cw2, Cw3 and DRw52. In general, the Uitoto Indians resemble, in their histocompatibility antigens, other Latin-American Indians so far studied.

Colombia↗

Tissue response to anodyne medicaments.

The tissue-irritating effect of anodyne medicaments was studied via enzyme histochemical evaluation of muscle tissue (screening test) and pulp tissue (usage test). Of the medicaments tested, formocresol was the most irritating, followed by Cresatin, eugenol, and oil of pimenta leaf. The effects of Cresatin, eugenol, and oil of pimenta leaf were not statistically distinguishable.

Animals↗

Intracardiac rhabdomyosarcoma: transesophageal echocardiographic findings and diagnosis.

Transesophageal echocardiography (TEE) was performed on a 41-year-old woman who presented with a cerebrovascular accident. TEE confirmed the presence of a morphologically bizarre biatrial tumor with precarious, vigorous motion throughout the cardiac cycle. Surgical intervention was decided on, and the patient underwent cardiac surgery for tumor excision 16 hours after TEE. Intraoperative frozen section diagnosis was spindle cell sarcoma, and subsequent immunohistochemical analysis showed the tumor to be a rhabdomyosarcoma. The data are presented here, and the role of TEE to establish a preoperative diagnosis of intracardiac tumor is discussed.

Adult↗

Primary epiploic appendagitis: CT manifestations.

Inflammation of an epiploic appendage is considered to be a rare cause of acute abdomen. Recently, it has been reported that typical computed tomography (CT) findings of primary epiploic appendagitis (PEA) provide a definitive diagnosis in most of the cases. However, since these papers are only few, they are easily overlooked by the practicing radiologists. Our purpose is to add four new cases to the existing literature and to perform a review of the literature.

Abdomen, Acute↗

HLA antigens in five Amerindian groups (Yuko, Bari, Tunebo, Guane and Paez) of Colombia: results of 'Expedición Humana'.

The serological HLA types (A, B, C and D loci) were studied in five different Indian groups in Colombia. The range of polymorphism was not very restricted in these groups, but there was significant genetic heterogeneity among the five populations in all the HLA loci. The gene frequency data, when converted into a kinship matrix and a two-dimensional eigen vector plot, showed a closer affinity between Bari and Yuko Indians, while Guane, Tunebo and Paez Indians were not only genetically different from the former but also well-differentiated from each other. It seems therefore from this study that geographical proximity may play a greater role than linguistic similarities in the genetic affinities of Colombian Amerindians.

Antigenic Variation↗

Surgery for aortic regurgitation in the young: repair versus replacement.

Aortic valve replacement in the young patient represents a serious problem in terms of anticoagulation and limited durability of the bioprosthesis. In order to determine the possible advantages of conservative surgery, consecutive patients with aortic regurgitation, aged below 35 and operated upon between July 1988 and July 1990 were analyzed. There were 149 patients (mean age 22 years). The aetiology was rheumatic disease in 122 (81.9%) and 83.2% of the patients were in NYHA class III-IV. Sixty-one valves were replaced (AVR) and 88 (59%) were repaired by a variety of techniques (annuloplasty, cusp unrolling, resuspension or extension). The mean ischaemic times for isolated aortic regurgitation were 73.6 mins for AVR and 80.5 mins for repair. Associated mitral surgery was performed in 94 patients (63%); 33% of these had a valve replacement and 67% a repair. In the AVR group there was 1 hospital death (2.2%), 2 late deaths (3.3%), 3 major embolic events (5%) and one reoperation for infection. In the repair group there were 2 hospital deaths (2.4%), but no late deaths or embolic events. Twelve patients required reoperation which was performed without mortality; this was due to aortic dysfunction in 4 cases (4.6%) and mitral dysfunction in 8. It is concluded that aortic valve conservation in a young, predominantly rheumatic, population can be performed in a significant number of patients with a low mortality and morbidity.

Adolescent↗

Substitution of the conserved phenylalanine in the S-adenosyl-L-methionine binding site of M.MspI with tyrosine modifies the kinetic properties of the enzyme.

Cytosine (C-5)-specific DNA methyltransferases share a set of ten conserved motifs distributed evenly throughout the entire polypeptide chain. The first conserved motif contains a Phe, which is intimately associated with cofactor recognition. In the pseudo-DNA methyltransferase M.SpoI, encoded by the pmt1 gene in Schizosaccharomyces pombe, a Tyr replaces this Phe residue. We describe the properties of a mutant form of M.MspI, a typical cytosine (C-5)-specific DNA methyltransferase, in which Tyr replaces the conserved Phe. This mutant shows differences in ternary complex formation and in the pattern of covalent complex formation with an inhibitory, fluorinated DNA duplex which may be due to anomalous hydrogen bonding between the mutant Tyr hydroxyl group and the catalytic loop of the enzyme or through interference with cofactor binding.

Binding Sites↗