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M Contreras

Publications and source records attributed to M Contreras.

277 records · Page 16Linked to original sources
PubMedDate not supplied

[Rupture of the free wall of the heart as cause of death in acute myocardial infarct].

Twenty four cases with myocardial rupture among 259 patients with autopsy after death due to myocardial infarction, were compared with patients with acute myocardial infarction and death secondary to other causes. Myocardial rupture occured during the first 72 hours in 58% of the patients and all cases within the first five days. Two thirds of the patients were males and 46% were 70 years of age. There were 24 myocardial ruptures (9.5%). Previous history of arterial hypertension and un-remittent anginal pain were predisposing factors for rupture (p=0.05). Other previously reported bad prognostic factors such as persistent hipertension after acute infarction, severe exercise before infarction and history of Diabetes Mellitus were not statistically significant in this study. Ruptured myocardium was not influenced by a previous history of myocardial infarction, hospitalization delay in the C.C.U., administration of anticoagulants, digitalis or pressor amines. There was no significant difference among the groups compared in enzyme curves or magnitude of leucocytosis. Electromechanic dissociation, sinus bradycardia, nodal rhythm followed by idioventricular rhythm and asystole, were observed following myocardial rupture.

Acute Disease↗
PubMedDate not supplied

[Pulmonary arterial hypertension of unknown etiology. Study of the cardiopulmonary function].

Thirty two cases of pulmonary arterial hypertension of unknown etiology (PAH-UE) were studied. The diagnosis was established by exclusion after the results of hemodinamics studies. Ninety percent of cases had severe PAH (100 mmHg). The end diastolic right ventricular pressure was elevated in 46% of cases. The total pulmonary vascular resistance was increased in the order of the 1700 dinas. seg. cm-5. The cardiac index was 3.3 1/m2 with a right ventricular work index of 3.96 K gm min. The total lung capacity (TLC) was normal, with a vital capacity (VC) of 78% of the predicted value. The residual volume was increased. The mean value of the maximal midexpiratory flow rate (MMFR) was 78%. The A-a gradient of O2 was 30 mmHg, with a venous mixture expressed as a percentage ratio of the cardiac output (Qva/Qt) of 26%. The mean paO2 mmHg and the anatomical pulmonary artery to vein shunt (Qs/Qt) was 9%, with a DLco normal. The clinical hemodinamic correlation was in good agreement. Our results suggested that PAH-UE "per se" has effect in pulmonary function changing slight lung mechanics, and in a moderate degree lung gas exchange. The hipoxemia results meanly from V/Q imbalance.

Adolescent↗
PubMedDate not supplied

Extraction of methamidophos residues from vegetables with supercritical fluid carbon dioxide.

A simple supercritical fluid extraction (SFE) method has been developed to efficiently extract incurred residues of methamidophos (a very polar pesticide) from fresh vegetable samples by using commercial SFE equipment and moderate SFE conditions. Vegetable samples were mixed with anhydrous magnesium sulfate and extracted with supercritical carbon dioxide at 300 atm and 50 degrees C with methanol as static modifier and a few milliliters of ethyl acetate as trapping system. Methamidophos recoveries were > 70% from 33 pepper, cucumber, and tomato samples at incurred levels ranging from 0.1 to 2.2 mg/kg. Triplicate analysis from 2 replicates at an incurred level of 0.53 mg/kg gave a coefficient of variation of 14%. Results for incurred residues of chlorpyrifos, endosulfan, and procymidone in some samples show that the SFE technique could be used as a multiresidue method.

Carbon Dioxide↗
PubMedDate not supplied

[Numerical taxonomy of staphylococci isolated from water and beach sand from Valparaíso and viña del Mar, Chile].

A total of 85 strains of Gram positive cocci isolated from beach water and sand located in Valparaiso bay, and Viña del Mar, Chile, were examined for 59 morphological, physiological and biochemical characteristics. The taxonomic data were analysed by numerical taxonomy using Ssm coefficient and the Unweighted Pair Group Method of Association (UPGMA). At 80% similarity level, four phenons were obtained. Of the 85 strains 31% were classified as Staphylococcus epidermidis, 9% were classified as Staphylococcus haemolyticus, 36% were classified as Staphylococcus spp. and 24% as Staphylococcus aureus. Epidemiological considerations are made in relation with the probable impact that the isolation of Staphylococcus aureus and coagulase negative Staphylococci would have on the health of the population.

Chile↗
PubMedDate not supplied

[The use of urea carbon 14 in breath tests as diagnostic method for Helicobacter pylori infections].

The Helicobacter Pylori has been indicated as a pathologic agent in the pathogenesis of antral gastritis, gastric and duodenal ulcers and probably in gastric cancer. Due to the high incidence of this infection in our place, we decided to look for a diagnostic method quick to perform, sensitive, reliable and no invasive. The breath test of 14C urea, based in the production of urea by the H. Pylori, represents this alternative. We have found, using does of 1 microCi, a high correlation with the diagnosis of H. Pylori by biopsies. We determined as negative less than 100 DPM, doubtful between 100 and 200 DPM and positive more than 200 DPM. The high pick of the curve keeps tight relation with the degree of infection. We checked this when we suppressed the H. Pylori with bismuth subsalicylate. The breath 14C Urea test showed high sensitivity (100%) and specificity (85.71%). We conclude that this breath test is an alternative way of diagnosing and follow up for H. Pylori infections. It is highly sensitive, reproducible and no invasive.

Adult↗