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Biomedical subjects

R Matamoros

Publications and source records attributed to R Matamoros.

11 recordsLinked to original sources
PubMed2005

Effect of grazing pasture with a low selenium content on the concentrations of triiodothyronine and thyroxine in serum, and GSH-Px activity in erythrocytes in cows in Chile.

AIM: To determine the effect of grazing pasture that had a low selenium (Se) concentration on serum concentrations of triiodothyronine (T3) and thyroxine (T4), and erythrocyte glutathione peroxidase (GSH-Px) activity in dairy cows. METHODS: Forty pregnant Friesian cows were grazed on pasture that contained 0.03-0.04 ppm Se on a dry matter (DM) basis. Two months before parturition, 20 cows were randomly selected and treated with 1 mg Se/kg bodyweight subcutaneously, as barium selenate (Group Se-S). The other group (Se-D) was not supplemented. Blood samples were taken before supplementation (-60 days) and 30, 60, 90, 180 and 270 days after parturition, for determination of concentrations of T3 and T4 in serum, and GSH-Px activity in erythrocytes. RESULTS: Erythrocyte GSH-Px activity in the Se-D group was <60 U/g haemoglobin (Hb) throughout the experiment. Supplementation increased (p<0.05) activities to >130 U/g Hb throughout lactation. Mean serum concentrations of T4 in Se-D and Se-S cows increased from 23.7 (SEM 0.7) and 23.4 (SEM 0.8) nmol/L, respectively, in the prepartum period to 69.6 (SEM 0.1) and 67.6 (SEM 0.2) nmol/L, respectively, at 180 days of lactation (p<0.01), and no effect of Se supplementation was evident. Serum concentrations of T3 in Se-D cows decreased (p<0.05) from 1.6 (SEM 0.1) nmol/L prepartum to 1.0 (SEM 0.2) nmol/L at the beginning of lactation, and remained lower (p<0.05) than those in the Se-S cows which did not decrease after calving and ranged from 1.9 (SEM 0.1) to 2.4 (SEM 0.2) nmol/L throughout lactation. CONCLUSIONS: Serum T3 concentrations decreased during early lactation in unsupplemented cows grazing pastures low in Se (0.03-0.04 ppm) and both serum T3 and erythrocyte GSHPx activities were consistently lower throughout lactation compared with Se-supplemented cows. Se supplementation had no effect on serum T4 concentrations.

Animal Feed↗
PubMed1997

From peptide to non-peptide. 3. Atropisomeric GPIIbIIIa antagonists containing the 3,4-dihydro-1H-1,4-benzodiazepine-2,5-dione nucleus.

The benzodiazepinedione class of non-peptidal GPIIbIIIa antagonists has been modified to allow the isolation of noninterconverting rotational isomers, or atropisomers, with the aim of examining their structure-activity relationships as compared to active RGD-containing peptides and other non-peptidal antagonists. Resolution of these antagonists was accomplished by the introduction of a tert-butyl group at N1 and a chlorine at C9 on the 3,4-dihydro-1H-1,4-benzodiazepine-2,5-dione nucleus and enantiospecific substitution on the beta-alanine side chain attached to N4. The relative configuration was determined by single-crystal X-ray analysis. Further, conformational analyses using ab initio calculations were performed to assess the conformational preferences about the beta-alanine side chain. The data support a good topographical correlation between the benzodiazepinedione class of antagonists and the "cupped" presentation of the RGD tripeptide sequence found in the cyclic peptide G4120. The relationship between these compounds with other peptidal and non-peptidal antagonists is discussed.

Benzodiazepinones↗
PubMed1992

[Exulceratio simplex Dieulafoy].

"Exulceratio simplex Dieulafoy" is a rare cause of massive upper gastrointestinal haemorrhage from a submucosal artery. Dieulafoy's disease is rarely recognized. We present 9 cases of Dieulafoy's lesion and have collected 176 cases described in the literature.

Adolescent↗
PubMed1988

Monitoring of somatosensory evoked potentials in carotid surgery: results, usefulness and limitations of the method.

We have monitored cortical somatosensory evoked potentials (SEP) during 177 carotid operations (167 carotid endarterectomies). An intraluminal shunt was always used for endarterectomy of the internal carotid artery (CEA). SEP was not readable in 21 operations. During 126 carotid operations, no alteration of SEP occurred. However, three patients had an immediate postoperative neurologic deficit while the SEP remained normal. Abnormal SEP occurred in 30 patients. In two cases irreversible loss of SEP was seen. Both patients awoke with a new neurologic deficit after the operation. We found reversible abnormal SEP in 28 cases. In 63 cases with contralateral stenosis, abnormal SEP caused by carotid clamping was observed in 15 (24%). The diagnostic sensitivity of intraoperative SEP monitoring in predicting neurologic outcome following carotid operation was 100% with a specificity of 40%. Monitoring of SEP during carotid surgery is a reliable and useful method to detect incipient cerebral ischemia and to determine the need for shunting. The prognostic value of SEP monitoring to predict postoperative neurologic deficits is limited by the low specificity of the method.

Adult↗
PubMedDate not supplied

Catheter-related bacteremia and fungemia. Reliability of two methods for catheter culture.

The purpose of this study was to analyze 98 febrile patients with suspected catheter-related bacteremia (CRB) or fungemia (CRF) and compare two different methods, one semiquantitative (SQ) (Maki's method) and the other quantitative (Q) (modification of Brun-Buisson method) to determine each ability for diagnosing CRB. Twelve patients had CRB or CRF. The sensitivity, specificity, positive, and negative predictive values, and efficiency using the Maki method were 83%, 84%, 42%, 97%, and 83%, respectively. The same parameters using the other method were as follows: 92%, 84%, 44%, 99%, and 84%, respectively. Although the diagnostic reliability in each method was similar, the Maki method was quicker and easier to perform in clinical microbiology laboratories.

Bacteremia↗