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Biomedical subjects

A Andrade

Publications and source records attributed to A Andrade.

At least 55 records · Page 3Linked to original sources
PubMed1994

Riboflavin-sensitized photoprocesses of tryptophan.

The photodegradation of tryptophan in oxygen saturated aqueous solution sensitized by riboflavin is accompanied by the generation of the following reactive oxygen species: 1O2, OH., H2O2 and O2.-. When parallel photodegradation experiments are run with 14C-riboflavin in one case and 14C-tryptophan in the other and the irradiation products are separated by Sephadex G-15 and C18-HPLC, the generation of the following species is detected: aggregate forms of riboflavin, indolic products associated to flavins, indolic products of molecular weight higher than tryptophan, formylkynurenine, and other tryptophan photodecomposition products. The significance of the riboflavin anion radical and tryptophan cation radical as intermediates in the photoproduct formation is discussed.

Catalase↗
PubMed1994

Atrial natriuretic factor in cirrhosis: relationship to renal function and hemodynamic changes.

Plasma atrial natriuretic factor concentrations and different hemodynamic parameters, including the evaluation of femoral arteriovenous shunting by measuring the arteriovenous difference of oxygen content (Ca-vO2), were determined in eight healthy subjects and 24 patients with cirrhosis without renal failure (group I: seven patients without ascites, group II: nine patients with ascites and UNaV > 10 mEq/24 h and group III: eight patients with ascites and UNaV < or = 10 mEq/24 h). Atrial natriuretic factor was 34 +/- 4.7 pg/ml in the control group and 44.28 +/- 5.4, 67.89 +/- 8.8 and 84 +/- 10.8 pg/ml in groups I, II and III respectively (p < 0.001. group III vs. I and control and II vs. control). Atrial natriuretic factor directly correlated with cardiac index (p < 0.01), blood volume (p: 0.01), femoral blood flow (p < 0.01) and inversely with systemic and femoral vascular resistances (p < 0.02), Ca-vO2 (p < 0.01), serum albumin (r: -0.61; p < 0.01) and prothrombin index (r: -0.63; p < 0.02). These results indicate that plasma atrial natriuretic factor is increased in patients with cirrhosis, especially in those with advanced disease and marked renal sodium retention. This suggests that in cirrhosis, arteriolar vasodilation and peripheral arteriovenous shunting influence renal function while inducing a state of overflow at the central venous compartment leading to increased atrial natriuretic factor secretion. Increased production of this vasodilatory hormone may thus contribute to the hyperkinetic circulation of cirrhosis.

Atrial Natriuretic Factor↗
PubMed1994

Transthoracic and transesophageal echocardiographic study of pulmonary autograft valve in aortic position.

Eleven patients who underwent pulmonary valve autograft to aortic position with placement of bovine pericardial prosthesis in pulmonary position were studied with echocardiography. The etiology of aortic valvuloplasty as determined by anatomopathological examination was rheumatic in five, degenerative in four, and congenital in two. Important mitral stenosis coexisted in two patients, and during the same operation as the Ross surgery, a mitral valvuloplasty with Carpentier ring was practiced on one and an open mitral commissurotomy on the other. Transthoracic echocardiography, which helped to confirm the viability of the surgery by determining the diameters of the semilunar valve rings and quantifying the severity of the aortic valve lesions, was performed on all patients before surgery and repeated 3 months later. Transesophageal echocardiograms were practiced on nine patients during the surgical procedure and repeated after 6 months on seven. The latter technique aided in immediate postoperative evaluation, and repetition at 6 months served to explore the ventricular infundibuli and evaluate pulmonary valve performance in aortic position. In conclusion, transthoracic and transesophageal echocardiography provide a practical and valuable means of investigating the pre-, trans-, and postoperative conditions of patients undergoing Ross surgery.

Adult↗
PubMed1993

Primary adrenocortical nodular dysplasia presented as adrenal adenoma by functional scintigraphy.

This is a report of a case of a 12-year-old boy with Cushing's syndrome in which high doses of dexamethasone failed to suppress glucocorticoid secretion. Neither CT nor MRI (morphologic studies) revealed any adrenal abnormality. Functional images with NP-59 (I-131 beta-iodomethyl-norcholesterol) clearly revealed intense unilateral uptake in the right adrenal gland. A right adrenalectomy was performed, and the pathologic diagnosis was primary adrenocortical nodular dysplasia. One year later, the cushingoid signs had virtually disappeared and urinary steroid excretion and serum cortisol levels were within the normal range. Nevertheless, primary adrenocortical nodular dysplasia is essentially a bilateral disease. In this case, a remission in the adrenocortical hyperfunction was observed. Although there was confusion in the etiological diagnosis, functional scintigraphy correctly indicated the status of adrenal function.

Adenoma↗
PubMed1993

Metabolic clearance rate of biosynthetic growth hormone after endogenous growth hormone suppression with a somatostatin analogue in chronic renal failure patients and control subjects.

OBJECTIVE: Several disturbances in the regulation of growth hormone secretion have been reported in chronic renal failure. The general assumption is that an altered hormonal clearance is at the basis of such GH alterations. Nevertheless, details of GH elimination kinetics in uraemia are not available. To clarify the role played by the kidney in its catabolism, GH elimination kinetics were studied in uraemic and control subjects after suppression of endogenous secretion of GH. DESIGN: In all subjects an analogue of somatostatin (octreotide 100 micrograms i.v.) was administered as a bolus before GH (-60 minutes). Sixty minutes later (0 min) biosynthetic GH (0.5 IU = 200 micrograms) was administered intravenously as a bolus. PATIENTS: Six chronic renal failure patients before dialysis and six matched normal volunteers. MEASUREMENTS: Plasma GH levels were measured by an immunoradiometric assay. RESULTS: In both groups, the GH elimination curve fitted a bi-exponential model. The calculated plasma volume and GH concentration at 0 minutes were similar in both groups, while uraemic patients presented a reduced distribution volume. In all parameters measuring GH elimination, chronic renal failure patients showed an impaired clearance. In fact, the area under the curve (mU/l/150 min) was 912.8 +/- 170.6 for controls and 3524.8 +/- 642.8 for chronic renal failure patients (P < 0.005). The GH half-life was 13.8 +/- 1.6 and 26.4 +/- 2.9 minutes for control and uraemic subjects respectively (P < 0.05), and the metabolic clearance rate MCR (ml/min/m2) was 265.3 +/- 50.6 for controls and 79.9 +/- 16.4 for uraemic patients (P < 0.05). The GH mean residence time (minutes) (MRT) calculated was 12.0 +/- 0.5 for controls and 31.8 +/- 4.6 for chronic renal failure patients (P < 0.05). CONCLUSIONS: Contrary to previous estimates, GH elimination kinetics follows a bi-exponential model and in normal subjects the GH half-life of the second phase is 13.8 +/- 1.6 minutes. Uraemic patients have impaired clearance of GH, suggesting that the kidney plays a role in GH disposal. However, the degree of impairment does not fully explain the alterations in GH secretion previously described in chronic renal failure.

Adult↗
PubMed1992

Antithyroid drug and Graves' hyperthyroidism. Significance of treatment duration and TRAb determination on lasting remission.

OBJECTIVE: To investigate the significance of treatment with antithyroid drugs longer than 12 months on lasting remission in Graves' hyperthyroid patients, and to study clinical and laboratory parameters of prognostic value. PATIENTS: Fifty-two untreated Graves' hyperthyroid patients were assigned at random to two therapeutic groups. They were treated with carbimazole during 12 and 24 months in Group I (n = 28) and Group II (n = 24), respectively. MEASUREMENTS: Serum levels of FT4, T3, sTSH and TSH receptor antibody (TRAb) were measured before starting treatment and at regular intervals during treatment and follow-up after drug withdrawal. We compared the relapse rate in both groups of patients, at short (2-yr) and long-term (5-yr) periods after drug withdrawal. Also, we compared clinical and biochemical parameters between patients who stayed in remission and who had relapse. RESULTS: At the end of the short-term period, relapse had occurred in 13 (46.4%) Group I patients and in 13 (54.1%) Group II patients, p = 0.36. At the end of the long-term period, relapse had occurred in 24 (85.7%) Group I and 20 (83.3%) Group II patients, p = 0.78. No difference could be observed between patients who had stayed in remission and who had suffered relapse, within the 5-yr follow-up period regarding to goiter size, frequency of ophthalmopathy, TSH and TRAb levels. CONCLUSIONS: The high relapse rate observed could be due to high iodine intake in our country. In this study and in a review of the available data, we have been unable to find any rational basis for courses of antithyroid drugs longer than twelve months for the treatment of Graves' hyperthyroidism.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Coronary atherosclerosis in acute myocardial infarct. Anatomic profile of diverse causes of death].

OBJECTIVE: to study the degree of coronary obstruction by atherosclerotic plaques in a population dying with acute myocardial infarction. We defined subgroups by the degree of the obstructive lesion and compared the severity and distribution of coronary atherosclerotic lesions in different groups according to cause. STUDY DESIGN: systematic prospective study in patients dying in the acute phase of myocardial infarction in a University Hospital Coronary Unit during a four years period. POPULATION AND METHODS: we studied 193 patients corresponding 77% of the patients dead in the same period. 24 patients were excluded by technical reasons related to the preparation of necropsic material. The clinical protocol included 64 parameters and were considered the following causes of death: left ventricular failure (shock or acute pulmonary edema), left ventricular free wall rupture, interventricular septum rupture, primary asystole, pulmonary embolism and ventricular fibrillation. To study of the heart we performed the transverse slices technic after fixation; to study the epicardial coronary arteries we isolated the coronaries after fixation and made 5 mm transverse slices. The slices were macroscopic and microscopic evaluated for the degree of coronary obstruction in every 5 mm segment. We classified the degree of coronary obstruction in five grades: less than or equal to 25%; greater than 25% e less than or equal to 50%; greater than 50% e less than or equal to 75%; greater than 75% e less than 100%; and total obstruction. RESULTS: the degree of coronary obstruction in each epicardial segment were: Right ostium--grade I = 21%, grade II = 46%, grade III = 26%, grade IV = 7%, grade V = 0; Right coronary--grade I = 5%, grade II = 10%, grade III = 19%, grade IV = 28%, grade V = 38%; Left ostium--grade I = 27%, grade II = 50%, grade III = 19%, grade IV = 4%, grade V = 0; Left main--grade I = 16%, grade II = 43%, grade III = 28%, grade IV = 10%, grade V = 2%; Anterior descendent--grade I = 1%, grade II = 5%, grade III = 11%, grade IV = 34%, grade V = 49%; Left circumflex--grade I = 2%, grade II = 14%, grade III = 22%, grade IV = 40%, grade V = 22%. The number of coronary arteries with more than 75% obstruction for each group of one, two or three vessel disease were: 1 vessel--41 cases; 2 vessels--56 cases; 3 vessels--68 cases. The number of vessels with more than 75% obstruction for each cause of death were: Wall rupture--1 vessel = 20, 2 vessels = 18, 3 vessels = 11; Septum rupture--1 vessel = 0, 2 vessels = 2, 3 vessels = 2; Shock--1 vessel = 12, 2 vessels = 21, 3 vessels = 30; Acute pulmonary edema--1 vessel = 1, 2 vessels = 9, 3 vessels = 7; Asystole--1 vessel = 4, 2 vessels = 1, 3 vessels = 8; Pulmonary embolism--1 vessel = 2, 2 vessels = 5, 3 vessels = 8; Ventricular fibrillation--1 vessel = 2, 2 vessels = 0, 3 vessels = 2. CONCLUSION: in most patients dying with acute myocardial infarction, the coronary atherosclerotic lesions were present in two or three epicardial coronary arteries. The left anterior descendent artery was the more frequent artery with major lesion (greater than 75%). Major atherosclerotic lesion in just one vessel were more frequent in patients dying by cardiac rupture.

Autopsy↗
PubMed1992

[Association between post-initial remission and HLA phenotype in Type I diabetics].

Our goal was to estimate the occurrence rate of the post-initial remission and its relation with HLA phenotype in type I diabetics (DMI). We studied 50 type I diabetics, 22 women and 28 men, with an average age at the onset of the disease to 15.8 +/- years (range 3-30 years). All patients were conventionally treated with insulin therapy, diet and regular exercise. Six (12%) of the diabetics presented a complete remission during 57.3 +/- 46 weeks, whereas fifteen (30%) patients presented partial remission during 20.1 +/- weeks. No significant differences were observed with regard to age at the onset of the disease, sex, BMI, initial ketoacidosis and stage of gonadal development between those diabetics presenting remission and those who did not presented so. We observed a higher incidence of the HLA-DR4 antigen among diabetics with remission (complete and partial, 61.9%), compared with patients without remission (20%, p less than 0.5). In conclusion, our results support the findings suggesting the presence of a clinical-immunological heterogenicity in DMI, genetically determined and linked to the HLA system.

Adolescent↗
PubMed1991

Altered growth hormone response after growth hormone releasing hormone administration in chronic renal failure.

Eleven chronic renal failure patients and 11 matched controls, received growth hormone GHRH (1 microgram/kg iv) or TRH (400 microgram iv) on separate occasions, immediately before undergoing hemodialysis. GHRH-induced GH peak in uremics (22.7 +/- 5.2 micrograms/l) was not different from that obtained in control subjects (16.0 +/- 4.3 micrograms/l). However, the uremic patients did not show the habitual post-peak fall, remaining GH levels over 10 micrograms/l till the end of the test. Differences between the two groups were significant (p less than 0.05). Uremic patients showed PRL values higher than in controls, however their TRH-induced PRL peak (20.6 +/- 6.6 micrograms/l) was not different from that of controls (26.5 +/- 3.0 micrograms/l). Again chronic renal failure patients showed PRL plasma values abnormally elevated till the end of the test. Differences between the two groups were significant (p less than 0.05). Administration of placebo to a different group of seven uremic patients did not alter GH and PRL plasma levels. This sustained secretion of both GH and PRL in uremia could be attributed to reduced kidney clearance. However, when subjects were examined individually both the GHRH- and the TRH-induced hormonal peaks and the subsequent fall were not different in both groups. Unlike with controls, in uremic patients GHRH-stimulated GH and TRH-stimulated PRL/GH peaks were dispersed throughout the 120 min period. In controls GH and PRL peaks clustered around 15-30 min. The peak dispersion created a false impression of flattened curves or sustained hypersecretion in uremia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Hepatitis by infectious mononucleosis].

Five adult patients presenting with clinical and laboratory manifestations of an acute hepatitis in the course of a hitherto undiagnosed infectious mononucleosis (IM) are reviewed. Chief complaints were intense malaise and prolonged fever (7 to 15 days prior to diagnosis). Serum aminotransferases were moderately raised in all patients; three patients had mild jaundice with a direct-reacting hyperbilirubinemia; 4 patients had an enlarged and tender liver. When making the differential diagnosis of causes of acute hepatitis, blood smear examination was crucial, showing atypical lymphocytes (Downey). The diagnosis of IM was confirmed by the demonstration of high serum titers of antibodies against Epstein-Barr virus, IgM class (4 patients) or heterophil antibodies (1 patient), plus peripheral lymph node enlargement (3 patients), splenomegaly (4 patients) and the time course of the disease. The relevance of blood smear examination as a practical tool in the diagnosis of causes of acute hepatitis is stressed.

Acute Disease↗
PubMed1990

[Mitral valve prolapse associated with Basedow's disease and active hyperthyroidism. Preliminary report].

We performed 2 dimensional echocardiograms to investigate the presence of mitral valve prolapse (MVP) in 21 patients with Graves disease and active hyperthyroidism. 22 healthy subjects were used as a control group. The incidence of MVP was 24% (n = 5) in hyperthyroid patients compared to 5% (n = 1) in normals (NS by Fisher's exact test). Age, T3 and T4 levels were similar in hyperthyroid patients with and without MVP, but the clinical course was longer in the former. A study in a larger group of patients may help establish the increased incidence of MVP in hyperthyroidism.

Adult↗
PubMed1990

Interpretation module for screening normal ECG.

This work concerns the development of a module for automatic recognition of normal ECGs, i.e. those whose waves morphology do not suggest physiopathological or structural heart alterations. Such a unit constitutes the central part of an administrative system under development which will aid in the management of ECG testing in the primary care delivery level in Chile. This system greatly contributes to the optimal allocation of resources in order to increase the test delivery coverage and to reduce the social and private costs involved. A main feature of the system is that it operates through the screening of normal ECG. This process is performed in a computerized unit whose core is the interpretation module. The design of such a module uses concepts and methods previously developed for the general problem of medical diagnosis, based on fuzzy set theory. The interpretation module parameters were adjusted considering hypothetical and real data covering a wide variety of normal and pathological cases. Then its performance was tested using more than one hundred patients' records chosen at random. Results of this test are given and a discussion, including a comparison with similar commercial equipment, is provided.

Diagnosis, Computer-Assisted↗
PubMed1989

[Clinical methods for evaluating infarct size and its anatomic correlations. A study conducted with 193 cases. II. Evaluation of infarct size by determining maximal creatine phosphokinase in serum. Enzimatico-anatomic correlations].

AIMS: To compare the infarct size calculated by the peak serum CK method with the anatomic infarct size in a population dying of acute myocardial infarction. CONCEPT AND PLACE OF THE STUDY: To use the method of peak serum CK in the assessment of infarct size, calculated by a method developed by the authors, in a population dying of acute myocardial infarction in a coronary care unit. METHODS: 193 patients who successively died with acute myocardial infarction entered the study. After establishing the exclusion criteria the anatomical infarct size was measured using the method developed by the authors of myocardial slices after fixation of the heart and by the peak CK method. The two methods were correlated using linear regression curves. RESULTS AND CONCLUSIONS: A global correlation between the two methods was found although wide scattered values were found. After dividing the population in several subgroups, the analysis showed that survival below 48 hours, death in left ventricular failure, inferior infarcts and reinfarction influenced negatively this correlation. The anatomical method showed its value for this kind of evaluation having always in mind its known limitations. The enzyme method looked less discriminating as peak CK, obtained by 12 h sampling will seldom reflect the peaks of CK liberation curve. As the study was applied to a population of patients dying of acute myocardial infarction its results cannot be applied without caution to a population of survivors. We anticipate that in such a population peak CK will have a better correlation with real CK peaks even with 12 hours sampling and therefore reflecting more accurately infarct size.

Autopsy↗
PubMed1989

[Clinical methods for evaluating infarct size and its anatomic correlations. Study carried out in 193 cases. III. Comparison of data on the evaluation of the infarct size using the QRS score and a method of maximal creatine kinase determination in the serum].

AIMS: To compare two methods concerning the clinical evaluation of infarct size--one using a QRS score, the other based on peak Ck values--applied to the same population. CONCEPT AND PLACE OF THE STUDY: to determine--based on previously established correlations between a QRS score and the anatomic total infarct size on one hand, and between the peak CK values and the anatomic recent infarct size on the other hand--which myocardial infarction subgroup constitutes the best indication for each method. The study took place in a Coronary Care Unit of a Central Hospital. MATERIAL AND METHODS: 193 patients who died successively of acute myocardial infarction through out 4 years were studied. After establishing the exclusion critéria, the QRS score was calculated according to the method of Selvester modified by Wagner, and peak CK values were evaluated. Infarct size, either recent or old, was determined by means of an anatomical method developed by the authors and based on Hackel's and Alonso's previous works. Correlations were established between data from each clinical method and those from the anatomical method. Several myocardial infarction subgroups were considered for comparison of the correlations found in each subset. RESULTS AND CONCLUSIONS: As long as QRS score was regarded, significant correlations were found between the evaluation by QRS score and anatomical infarct size in the subgroups of patients with severe pump failure, prior myocardial infarction, or total loss of ventricular muscle mass of at least 20 percent; however, a significant correlation was missing when the whole myocardial infarction group was taken into consideration. When peak CK value were considered, a weak significant correlation was found between the evaluation by enzyme determination and anatomical infarct size in the whole group of patients, but a stronger correlation was present in the subgroups of patients with survival longer than 24 hours, anterior wall myocardial infarction, free wall cardiac rupture, or first acute myocardial infarction. In conclusion the choice of the method to be used in the clinical evaluation of infarct size should take into account the type of population beeing studied, and follow the results obtained in different myocardial infarction subgroups as mentioned above.

Creatine Kinase↗
PubMed1989

[2 cases of acute myocardial infarct complicated by fatal pulmonary embolism].

Two cases of pulmonary embolism with lethal course in the setting of acute myocardial infarction are presented. Both cases are clinically characterized by a late pulmonary embolism occurrence (2nd and 3rd week, respectively), and the presence of a large infarct, heart failure during acute myocardial infarction evolution and the interruption of anticoagulant therapy due to a complication. From the anatomic point of view, both cases had large hearts and very large biventricular infarctions. On the other hand, deep venous plexus constituted the pulmonary embolism origin in one case, and right ventricular thrombosis in the other.

Aged↗