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Biomedical subjects

E Salazar

Publications and source records attributed to E Salazar.

At least 19 recordsLinked to original sources
PubMed1991

High frequency of coinfecting enteropathogens in Aeromonas-associated diarrhea of hospitalized Peruvian infants.

Rectal swabs from 391 infants less than 18 months of age who were hospitalized with acute diarrhea and from 138 similarly aged healthy infants were examined for the etiologic agents of diarrhea. Aeromonas spp. were recovered from 205 of 391 (52.4%) diarrheic patients, whereas they were recovered from 12 of 138 (8.7%) controls (P less than 10(-11). Among the 205 Aeromonas-positive diarrheic patients, 118 (57.6%) were found to be coinfected with other common enteropathogens. Of the 164 Aeromonas-positive initial diarrheic specimens, 82 (50.0%) had one or more other enteropathogens present; 30 patients were coinfected with rotavirus, 20 with enterotoxigenic Escherichia coli, 16 with Campylobacter spp., 14 with Shigella spp., 13 with enteropathogenic E. coli, 4 with Vibrio spp., 1 with Salmonella spp., and 1 with Plesiomonas spp. of Aeromonas strains from cases compared with that from controls supports an etiologic role for this organism. However, frequent concomitant infections with other well-recognized enteropathogens and a lack of disease correlation with common Aeromonas phenotypes suggest that only a subset of Aeromonas strains may be diarrhea causing and that such strains may be common to several of the existing species.

Aeromonas↗
PubMed1986

Risks of anticoagulant therapy in pregnant women with artificial heart valves.

In an attempt to identify the best treatment for pregnant women with cardiac-valve prostheses who are receiving oral anticoagulants, we studied 72 pregnancies prospectively. In 23 pregnancies (Group I), the coumarin derivative acenocoumarol was discontinued and the patients received 5,000 U of subcutaneous heparin every 12 hours from the 6th to the 12th week of gestation, in 12 pregnancies (Group II), heparin was not substituted for the coumarin derivative until after the 7th week, and in 37 pregnancies, detected after the first trimester (Group III), the coumarin derivative was given throughout gestation. In most patients heparin was again substituted for the oral anticoagulant after the 38th week. Three mothers had thrombosis of a tilting-disk mitral prosthesis (two cases were fatal) during heparin treatment. No differences were found in the rates of spontaneous abortion in the three groups. Coumarin embryopathy occurred in 25 percent and 29.6 percent of the pregnancies in Groups II and III, respectively. We conclude that in the second and third trimesters of pregnancy, coumarin derivatives provide effective protection against thromboembolism while causing few fetopathic effects, but that these agents are contraindicated from the 6th to the 12th weeks of gestation. Low-dose heparin does not protect against prosthetic-valve thrombosis, and the possibility that a larger dose might be more effective requires further exploration.

Abnormalities, Drug-Induced↗
PubMed1984

Copper distribution in the normal human brain.

Copper concentration was determined in samples from 38 areas of 7 normal human brains. The grey matter contained higher concentrations of copper than the white matter. Identical areas of the grey and white matter of the cerebral cortex showed significant differences between individuals. In the caudate nucleus the highest concentrations of copper were found in the tail followed by the body and the head, respectively. A negative linear regression between age and brain copper levels was demonstrated.

Adolescent↗
PubMedDate not supplied

Comparative genotoxic effects of the cooked-food-related mutagens Trp-P-2 and IQ in bacteria and cultured mammalian cells.

As part of a major study to evaluate the mutagenicity of chemicals produced during the cooking of foods, we examined the responses of bacteria and cultured Chinese hamster cells to the compounds Trp-P-2 (3-amino-1-methyl-5H-pyrido[4,3-b]indole) and IQ (2-amino-3-methylimidazo[4,5-f]quinoline), constituents identified in cooked beef and fish. In the Ames/Salmonella tester strain TA1538, both compounds were confirmed to be extremely potent mutagens that were active at levels below 1 ng/plate in the presence of hamster-liver S9 microsomal fraction. 50-fold higher doses of both compounds were required for mutagenicity in the uvr+ tester strain TA1978. Trp-P-2 also behaved as a strong mutagen in CHO cells using the standard exogenous activation with hamster-liver S9 fraction. At concentrations below 1 microgram/ml it produced dose-dependent increases in cell killing, mutations at the hprt and aprt loci, sister-chromatid exchanges, and chromosomal aberrations. An excision-repair-deficient strain was about 2-fold more sensitive than the normal CHO cells with respect to these genotoxic effects of Trp-P-2. IQ had unexpectedly weak activity for all genetic endpoints in the CHO cells, and it produced clear-cut responses only in the repair-deficient cells and only above a concentration of 10 micrograms/ml. The toxicity that was observed with IQ was not affected by the repair capacity of the cells and was not associated with chromosomal aberrations, indicating that damage to cellular structures other than nuclear DNA was likely the predominant pathway for cell killing. Because the culture conditions normally used for CHO cell exposure were shown to be competent in producing bacterial mutagenicity with IQ, it was concluded that the active metabolite of IQ was present in the medium but was somehow ineffective in reaching the DNA of CHO cells and/or reacting with it. These results suggest that the relative mutagenic potency of compounds in Salmonella may bear no direct relationship to relative mutagenicity in CHO cells, emphasizing precaution in attempting to extrapolate microbial data to mammalian somatic cells. This study illustrates the use and merits of a multi-endpoint assay for genetic damage in CHO cells, the utility of using CHO cells that are defective in excision repair of DNA, and the importance of comparative testing between bacterial and mammalian systems.

Animals↗
PubMedDate not supplied

Lipids and lipoproteins in subjects at 1,000 and 3,500 meter altitudes.

To assess the relationship between altitude, atherogenic, and anti-atherogenic lipoprotein cholesterols (low- [C-LDL] and high [C-HDL] density lipoprotein cholesterols, respectively), 136 and 94 Venezuelan Mestizos living at 1,000 and 3,500 in elevation were studied. The two groups did not differ in regard to height, weight, ethnic origin, social or economic status, nutritional patterns, age, or occupation. Both groups had a high level of daily physical exertion, an imperative in their subsistence rural agricultural economy. Due to the mountainous terrain, high altitude residents were thought to have increased levels of physical activity. Males and females at high altitude had significantly lower plasma total cholesterol and C-LDL levels, and slightly lower C-HDL levels than those at low altitudes. It is speculated that reduced coronary heart disease event rates at high altitude might be related to lower levels of the atherogenic lipoprotein cholesterol, C-LDL.

Adult↗
PubMedDate not supplied

[Treatment of supraventricular paroxysmal tachycardia and auricular flutter by auricular stimulation].

Although the management of supraventricular tachycardias (SVT) and atrial flutter (AF1) with drugs or cardioversion is usually effective, their use in the high risk patient commonly digitalized, may be dangerous. Since the availability of an alternate therapeutic method is desirable, the usefulness of atrial pacing was evaluated in 31 episodes of tachyarrhythmia in 31 patients with varied heart conditions. The arrhythmia diagnosis and the stimulation were done through a right atrial electrode. In most cases the rate of stimulation was higher than that of the atria (up to 400 stimuli per min). Of 17 cases with SVT (four with preexcitation syndrome), pacing led to sinus rhythm (SR) in all, even though it was transient in two. SR was obtained in six of eleven cases of AF1, through a short lasting atrial fibrillation (AF) in three of them. Four patients with paroxysmal atrial tachycardia with A-V block changed to AF. SR was achieved shortly after termination of the procedure in two of the latter. It is concluded that atrial pacing is a valuable therapeutic method since it is effective, it has very low risk specially in digitalized patients, its does not require anesthesia and because it may be used repeatedly in case of recurrence. The technique of atrial pacing permits, in some cases, the identification of the mechanism responsible for the arrhythmia.

Adolescent↗
PubMedDate not supplied

[Correlation between exercise test and coronariography].

In order to evaluate the sensibility and specificity of the maximal treadmill exercise-stress test, a correlation was made, in fifty patients, of the resus of the test and the findings at selective coronary arteriography. None of the patients had received cardioactive drugs previous to the study. Among twenty-nine patients with proven coronary disease, three had false negative exercise tests. The remaining twenty-six cases had positive tests. The sensitivity of the method (reliability in identifying the presence of disease) was 89.7%. Twelve of twenty-one subjects with normal coronary arteries had negative exercise tests. In eight patients without coronary artery lesions, the exercise test was positive (false positive tests). An additional patient had an equivocal response and is included among the false positive responses. These nine-patients form a special group since they had severe heart disease, even though it was not due to atherosclerosis of the major coronary vessels. The specificity of the test (reliability in identifying the absence of disease) was 57.1%. However, in the absence of other heart disease, none of the subjects with normal coronary arteries had a false positive response. An analysis is made of the possible causes of these false negative and false positive responses. It was also shown in this study that the patients with coronary artery disease and positive treadmill tests had a definite functional aerobic impairment as well as a significant reduction in such indices of myocardial oxygen consumption as the heart rate and the double product (pressure-pulse), when compared to the subjects with normal coronary vessels and negative tests. In the group of patients with false positive responses, these parameters were not significantly different from the normals. The exercise-stress test protocol used in this study appears to have an adequate sensibility and an acceptable specificity.

Adult↗
PubMedDate not supplied

[Aerobic functional capacity in normal subjects].

The functional evaluation of a subject may be performed by measurement of the functional aerobic capacity by means of exercise-stress tests. The maximal oxygen consumption (VO2 max) is the best parameter to establish this. The values of VO2 max were determined in twenty-five normal subjects, residents of Mexico City. There were twenty men and five women whose ages ranged between the third and fourth decades of life. A maximal exercise-stress test was performed in a treadmill, with constant inclination and progressive speed increments. Electrocardiogram and blood pressure were monitorized at rest, during exercise and in the recovery period. Four collections of espired gas were obtained, one at rest and three at different levels of exercise. VO2/kg. at rest (the value of one met) was 3.49+/-0.58 ml/kg. min. for the whole group somewhat lower for males (3.37+/-0.53 ml/kg. min.) than for female subjects (3.99+/-0.51 ml/kg. min.). These results are comparable to the ones informed in the literature. VO2 max/kg. was 27.8+/-5.57 ml/kg. min. for the entire group and 28.0+/-5.64 and 27.3+/-5.94 ml/kg. min. for men and women respectively. The values of VO2 max/kg. are definitely lower than the ones obtained from normal subjects in other countries. Considerations are made on the possible causes of this discrepancy. A linear correlation was found between VO2/kg or mets in one side and load imposed, cardiac rate or double product (pulse-pressure) in the other. The different VO2 max/kg. values found in this study as compared to the results obtained from other countries, serve to emphasize the need for each laboratory to establish its own normal values and to construct nomograms for the adquate evaluation of functional aerobic capacity. This, in turn, will permit the accurate and correct prescription of exercise for individual subjects or patients.

Adult↗
PubMedDate not supplied

[Antiarrhythmic effects of verapamil].

The effect of verapamil were studied on 50 episodes of supraventricular and ventricular tachycardia in 44 patients. An i.v. dose of 0.10 to 0.15 mg/kg. was used. In 5 cases His bundle electrograms were obtained while maximal dp/dt was determined in 7 others. Sinus rhythm was obtained in 21 (81%) of 26 cases of PSVT. In all cases of rapid atrial fibrillation (n-11), an important decrease in the ventricular response was elicited. Of 7 cases of atrial flutter, verapamil induced sinus rhythm in 3 and a significant decrease in the ventricular rate in 3 others. In 2 out of 6 cases ventricular tachycardia reverted to sinus rhythm. The latency time between the injection and the manifestation of the effect ranged from 2 to 4 minutes. A slight and short-lasting depression of dp/dt was observed in all cases studied. Verapamil produced an increase in the A-H interval in 4 of the 5 cases studied with His bundle recordings. Verapamil was found to be a useful drug to suppress PSVT, to decrease the ventricular response in flutter or atrial fibrillation and to convert some ventricular tachycardias to sinus rhythm. Verapamil should be used with caution in previously digitalized patients and is contraindicated when there is S-A node dysfunction as in the tachycardia-bradycardia syndrome.

Adult↗
PubMedDate not supplied

[A low-level stress test, in the early phase of myocardial infarction and its correlation with coronary angiography].

In a prospective 24-month trial at the Instituto Nacional de Cardiologia, 56 patients were studied. All patients had acute myocardial infarction (AMI), diagnosed by clinical, electrocardiographic and enzymatic means. They were studied in two groups: Group A with single localized AMI (n = 30) and Group B with AMI at two locations (n = 26); a resting electrocardiogram (EKG) was analyzed in each case and a low level stress test was performed within the 2nd and 3rd postinfarction weeks; coronary angiography was done between the 8th and 9th postinfarction weeks. In Group A the low level stress test (LLST) was positive for ischemia at a distance from the infarction site in 21, and eighteen of them had multi-vessel injuries (MVI); in 9 the LLST was negative; of these 7 had single-vessel injury; only the remaining 2 had MVI (p less than 0.001) with 90% sensitivity and 78% specificity. In Group B there was no significant relationship between LLST and coronary angiography (64% sensitivity, and 62% specificity). Relating the ischemic change at a distance in the resting EKG with coronary angiography, we found 75% sensitivity and 55% specificity in Group A. In Group B, sensitivity and specificity were even lower. We conclude that LLST in the early postinfarction phase in Group A is a safe and reliable method to suspect MVI, allowing the early identification of patients with lesions that could be treated by surgical means.

Coronary Angiography↗
PubMedDate not supplied

[Diltiazem in chronic stable angina].

The safety and efficiency of the administration of diltiazem was evaluated in 10 patients with class II-III chronic stable angina. All the patients had ischemic heart disease documented by coronary angiography and/or an abnormal exercise test. A dose related improvement in both frequency of angina and exercise capacity were obtained by diltiazem administered in increased doses using a single blind protocol. The weekly frequency of angina was reduced from 7.5 +/- 9.8 with placebo to 3.8 +/- 5.5, 1.1 +/- (p less than 0.05) and 0.7 +/- 0.9 (p less than 0.01) with doses of 120, 240 and 360 mg/day respectively. The exercise duration on treadmill was significantly increased from 8.5 +/- 3.6 to 10.6 +/- 3.7 min (p less than 0.05) with the 360 mg/day dose. The mean exercise time required to develop 1 mm ST depression was 6.1 +/- 3 min on placebo and was significantly delayed to 9.0 +/- 3.8 min (p less than 0.05) with the 240 mg/day dose and to 10.7 +/- 4.0 min with 360 mg (p less than 0.01). In a double blind randomized crossover phase, the time to the onset of ischemia during exercise was increased from 8.5 +/- 3.8 min with placebo to 11.05 +/- 2.8 min with 360 mg/day of diltiazem (p less than 0.01). Diltiazem in doses ranging from 120 to 360 mg/day is an effective antianginal agent with no significant adverse effects.

Adult↗
PubMedDate not supplied

[Clinico-angiographic correlations in myocardial infarction in young people].

We report 41 patients with myocardial infarction who were less than forty years old and that had been studied by coronary angiography. 97.5% were male mostly in their thirties. Coronary risk factors in this group were similar to the old one; excepting for mental stress present in 75% of our patients. There was not predominant infarction site. We observed different disturbances of the cardiac rhythm but no patient had congestive heart failure or cardiogenic shock. Mortality due to the infarct itself was none .61% of the cases had univascular lesions or normal coronary angiography and only 12% had trivascular lesions. The patients with normal coronary angiography had no significant difference in the mayor coronary risk factors and in our group we found patients with arterial hypertension, hyperlipidemia, cigarette smoking and obesity. We suggest that mental stress is an important coronary risk factor; the evolution of these patients is favorable and the mortality is low as compared with previous reports.

Adolescent↗
PubMedDate not supplied

[Myocardial infarct without pathologic Q waves].

Neither the presence nor the absence of pathological Q waves are related to the transmural or subendocardial localization of an acute myocardial infarction. The prognosis of an acute myocardial infarction without pathological Q waves is controversial. We studied 23 hospitalized patients with prolonged, typical chest pain, enzymatic elevation, an EKG without pathological Q waves but with changes in ventricular repolarization and a positive scintigraphy with radioactive pyrophosphates. The patients were classified in two groups according to the pattern of pyrophosphate uptake; group A had grade 2+ focal uptake (N = 13) and group B with grade 2+ diffuse uptake (N = 10). The level of serum glutamic transaminase was significantly greater in group A as compared to group B (p less than 0.05). However, levels of creatine kinase and lactic dehydrogenase were no different. The clinical hospital course was similar in both groups. Eleven patients were followed by 31.7 months: 30.4% had chronic angina, one underwent coronary bypass surgery, another suffered a recurrent myocardial infarction and there were no deaths. The diagnosis of acute myocardial infarction should be suspected in patients with prolonged angor pectoris, electrocardiographic changes in ventricular repolarization, increased enzymatic levels and a positive scintigraphy with a grade 2+ diffuse myocardial uptake of Tc 99m pyrophosphates. The diagnosis is certain if the uptake has a focal distribution.

Aged↗
PubMedDate not supplied

[Coronary arteriovenous fistula. Study of 14 cases].

Fourteen cases of coronary arteriovenous fistulae observed at the Instituto Nacional de Cardiología Ignacio Chávez were analyzed. The fistula originated from the right coronary artery in 57.1% of the cases, from the left coronary artery in 35.7% and from both coronary arteries in 7.2%. Drainage occurred into the right ventricle in 71.4% of the cases, into the right atrium in 7.2% and into the main pulmonary artery in 21.4%. The physical, roentgenological and electrocardiographic findings are undistinguishable from those usually obtained in malformations with a shunt between the aorta and the right heart or the pulmonary artery. Definite diagnosis is made at angiography. 2D and Doppler echocardiography may also be very useful. Natural history depends on the age of the patient, the size of the arteriovenous shunt, the presence of pulmonary hypertension and the development of complications. Even though malformations with small shunts may be well tolerated, serious complications are frequent and, thus, 14.3% of the patients developed infective endocarditis, 42.9% were in heart failure, 14.3% complained of angina pectoris and 54.5% had pulmonary hypertension. Mortality in this series was 28.6%. Early elective ligation seems to be the optimal treatment of coronary arteriovenous fistulae. The surgical procedure, however, is not devoid of risk. Thus, two of the three patients in this series who were operated upon after 1967 developed perioperative myocardial infarctions. Improvement in surgical technique should prevent this complication.

Adolescent↗