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R Fernandes

Publications and source records attributed to R Fernandes.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Gastric adenocarcinoma and carcinoid].

The authors present a case report of synchronous gastric carcinoid and adenocarcinoma. The diagnosis of gastric carcinoid and its association with gastric carcinoma is discussed.

Adenocarcinoma↗
PubMed1996

A technical approach to the evaluation of glucose oxidation: implications for diabetic cataract.

Oxidative stress has recently been involved in a number of diseases including development of diabetic cataract. If hyperglycemia is the relevant factor in diabetes, then it is reasonable to assume that under physiological conditions glucose may be toxic. The mechanisms involved in such a type of glucose 'toxicity' are still poorly understood but may involve glucose autoxidation. In this study we discuss a new methodological approach to the evaluation of glucose-induced oxidative damage to bovine lens membranes. The method is based on the incorporation of a fluorescent probe (parinaric acid) into lens membranes. The oxidative degradation of the probe is evaluated by monitoring its fluorescence decrease. It was possible to show that glucose may induce oxidative damage in the presence of trace amounts of transition metals. Furthermore, the data obtained by monitoring oxidative degradation of parinaric acid could be related to the amount of thiobarbituric acid-reactive substances formed under identical periods of time. The technique was shown to be reproducible, straightforward and highly sensitive as compared to other classical methods. Moreover, this methodological approach allows not only the evaluation of the extension of oxidative stress inflicted upon lens membranes but also the evaluation of the antioxidant effect of various compounds including some drugs with a potential anticataractogenic effect.

Animals↗
PubMed1996

An experimental model for the evaluation of lipid peroxidation in lens membranes.

Lipid peroxidation has been associated with a number of specific manifestations related both to lens aging and cataract development. The assessment of the effect of various naturally occurring prooxidants as well as the development of antioxidant strategies has often been limited by the lack of appropriate and simple experimental models. In this study we discuss the adaptation of a method based on the incorporation of a fluorescent probe (parinaric acid) into biological membranes to monitor early stages of lipid peroxidation. After establishing the appropriate conditions, the method can be successfully applied to study peroxidation in bovine lens membranes, allowing for the evaluation of the effect of several free radical generating systems, including the following metal-dependent initiators: ascorbate/ iron, hydrogen peroxide/copper and cumene hydroperoxide/ copper. The inhibitory effect of the chelating agent diethylene-triaminepenta-acetic acid and the competitive hydroxyl radical scavenger sorbitol, was consistently observed on parinaric acid degradation, on hydroxyl radical yield and on the amount of thiobarbituric acid reactive material produced. It could be shown that oxidative degradation of the probe gives direct information on lens membrane susceptibility to a specific peroxidation system. Parinaric acid can therefore be used as an efficient oxidation probe to evaluate oxidative damage inflicted to lens membranes by different systems, allowing also the evaluation of the antioxidant effect of various drugs including those with potential anticataractogenic effect.

Animals↗
PubMed1996

Nuclear microprobe applied to the study of coronary artery walls--a distinct look at atherogenesis.

The Nuclear Microprobe technique was employed to investigate the elemental concentration alterations due to atherosclerosis, of minor and trace elements at the different cellular layers and structures of freeze-dried cryosections of human coronary arteries. Nuclear Microprobe analyses enable to determine 7 elements, i.e., P, S, Cl, K, Ca, Fe and Zn in the artery walls. Early modifications of the vessels, due to the atherosclerosis progression, that cannot be detected with specific staining or conventional histological methods could be detected. These modifications comprise the disruption of elastic laminae and are apparently related to abnormal Fe and Zn depositions in the intimal region and surroundings of the elastic laminae. Later on, the calcification of these regions occur, contributing to an irreversible damage of the elastic laminae and leading to the atheroma growing and maturation. Moreover, the Fe and Zn content alterations and distribution in the vessel wall can characterize stages of the disease.

Arteriosclerosis↗
PubMed1995

Familial relationships between obesity and NIDDM.

Obesity and family history of diabetes are both risk factors for non-insulin-dependent diabetes mellitus (NIDDM), but it has been proposed that lean individuals with NIDDM have a greater load of diabetes susceptibility genes. If this is the case, one might expect a high prevalence of NIDDM in relatives of diabetic individuals with a low body mass index (BMI). Among Pima Indians participating in an epidemiological study, prevalence of NIDDM was evaluated in relation to BMI of a diabetic parent or to the average parental BMI when both parents had diabetes in 1,535 offspring from 547 families. Prevalence of NIDDM was also evaluated in relation to BMI of a randomly selected index diabetic sibling in 1,722 siblings from 721 families. NIDDM was diagnosed by an oral glucose tolerance test. Compared with offspring of diabetic parent(s) at the 25th percentile of BMI, the odds ratio (OR) for diabetes in offspring of diabetic parents at the 75th percentile was 0.6 (95% confidence interval [CI] 0.5-0.7), adjusted for age, sex, BMI in offspring, number of diabetic parents, and age at onset of diabetes and sex of the diabetic parent(s). In the analysis according to BMI in a diabetic sibling, the corresponding OR was 0.8 (95% CI 0.6-0.9). Risk ratios were only modestly higher when the analysis was restricted to relatives of subjects whose BMI had been determined before the onset of diabetes. NIDDM in the presence of a low BMI is more strongly familial than that at a higher BMI.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The Explanatory Model Interview Catalogue (EMIC). Contribution to cross-cultural research methods from a study of leprosy and mental health.

The Explanatory Model Interview Catalogue (EMIC) has been developed to elicit illness-related perceptions, beliefs, and practices in a cultural study of leprosy and mental health in Bombay. Leprosy is an especially appropriate disorder for studying the inter-relationship of culture, mental health and medical illness because of deeply rooted cultural meanings, the emotional burden, and underuse of effective therapy. Fifty per cent of 56 recently diagnosed leprosy out-patients, 37% of 19 controls with another stigmatised dermatological condition (vitiligo), but only 8% of 12 controls with a comparable non-stigmatised condition (tinea versicolor) met DSM-III-R criteria for an axis I depressive, anxiety or somatoform disorder. Belief in a humoral (traditional) cause of illness predicted better attendance at clinic.

Adaptation, Psychological↗
PubMed1990

Determination of fluoxetine and norfluoxetine by high-performance liquid chromatography.

A high-performance liquid chromatographic assay was developed for a recently introduced atypical antidepressant, fluoxetine and its demethylated metabolite, norfluoxetine. Prior to analysis, aliquots of alkalinized plasma were extracted with n-hexane and isoamyl alcohol, followed by back-extraction with diluted phosphoric acid. These extracts were injected into a 10 microns, reversed-phase C18 column with phosphate and acetonitrile as the mobile phase and detection at 214 nm. Peak height ratios were linearly correlated up to 800 micrograms/l. Acceptable coefficients of variation were demonstrated for both within-run and day-to-day studies. Selected drugs were checked for interference. The assay was used to monitor nine patients receiving 20 to 80 mg of fluoxetine per day. Plasma concentrations of fluoxetine and norfluoxetine ranged from 37 to 301 micrograms/l and 29 to 326 micrograms/l respectively.

Chromatography, High Pressure Liquid↗
PubMed1986

Alcohol use among adolescents in São Paulo, Brazil.

Drinking habits was studied in a sample of 3114 students from a low socioeconomic level and aging from 9 to 18 years. Males and females were equally represented in the sample. The survey showed that 27% were non-drinkers, 54% experimental drinkers, 14% moderate regular drinkers and 5% excessive regular drinkers. The excessive regular drinkers reported a higher proportion of heavy alcohol consumption among close relatives, mainly fathers. Sex and age-related differences were found in the drinking pattern. Males as well as oldest students were over represented among the drinkers excepted for excessive regular drinkers where no age difference was detected. This finding (same proportion of excessive regular drinkers in all age groups) was discussed taking into account the possibility that the high drop out rates in Brazilian schools could be introducing a bias in the figures found for the oldest adolescent groups. Beliefs about drinking consequences and location where most drinking occurs were also studied.

Adolescent↗
PubMed1985

Assessment of blood collection systems for the high performance liquid chromatography measurement of propranolol.

The effect of blood collection devices on the high performance liquid chromatography (HPLC) measurement of propranolol was assessed. Blood was collected from hypertensive patients treated with propranolol for at least 7 days. Two venipunctures (opposite arm technique) were performed on each patient using the reference (syringe/silanized, ethylene diamintetraacetate tubes) procedure and the Vacutainer Brand Tubes (lavender-, royal blue-, green-, and red-stoppered) that were free of tris(2-butoxyethyl) phosphate. Propranolol concentrations were determined utilizing a published HPLC procedure. This study showed that in the four evacuated tubes, propranolol concentrations in serum or plasma were highly correlated to those of the reference procedure (correlation coefficients, 0.986 to 0.997; and slope, 0.912 to 1.013). Mean propranolol concentrations of the red-stoppered tube serum were lower (7.5%) than that of the reference syringe (0.01 less than p less than 0.05). Thus, lavender-, royal blue-, green-, and red-stoppered tubes would be acceptable for propranolol monitoring.

Blood Specimen Collection↗
PubMed1985

A double-blind trial comparing mianserin and maprotiline in depressed inpatients.

The antidepressant effects and side effects of mianserin and maprotiline were assessed in a double-blind trial in 62 inpatients (34 men and 28 women; mean age, 43.6 years) with primary depressive illness. For the first week of the trial, 32 patients received 30 mg/day of mianserin and 30 patients received 75 mg/day of maprotiline; for the next three weeks, the dosage of each drug was doubled. According to scores on the Hamilton Psychiatric Rating Scale for Depression, administered on days 0, 7, 14, 21, and 28, the antidepressant effects of the two drugs were virtually identical. Results of electrocardiographic and vectorcardiographic recordings and other measurements indicated that by day 28 the QRS duration was significantly longer (P less than 0.05) in the maprotiline group. On days 14 and 28, mean systolic blood pressure was significantly higher (P less than 0.05) in the maprotiline group. By day 28, the incidence of anticholinergic side effects--constipation and dry mouth--was significantly higher (P less than 0.05) in the maprotiline group. Although maprotiline's effects on heart functions never reached clinical significance, its anticholinergic side effects could be bothersome, especially to older patients.

Adolescent↗
PubMed1980

[Not Available].

Explore the source record for details and available documents.

Academies and Institutes↗
PubMed1980

Echocardiographic estimation of pulmonary artery pressure in infants and children with congenital heart disease.

Echocardiography was used to study the quantitative and qualitative alterations of pulmonary valve echograms. 228 infants and children with congenital heart disease and with known pulmonary artery pressure were studied to evaluate which echocardiographic parameters would be most useful in predicting pulmonary artery hypertension. Right ventricular systolic time intervals (RVSTI) were studied and when patients with complete right bundle branch block (CRBBB) or transposition of the great arteries (TGA) had been excluded the strongest correlation was found between right ventricular preejection period/right ventricular ejection time (RPEP/RVET) and pulmonary artery diastolic pressure (PADP) (r = 0.73). In patients with TGA the correlation coefficient for LPEP/LVET and PADP was r = 0.88. We did not find a significant correlation between right ventricular isovolumetric contraction time (RICT) or RICT/RVET and PADP in patients with CRBBB. The correlation between the amplitude of the a-wave and PADP was fair (r = 0.48). BC slope, EF slope and the maximum amplitude of opening of the pulmonary valve were all related to PADP but the correlation coefficients were low. A-wave of 2 mm or less, systolic fluttering or systolic notching of the pulmonary valve echo were seen significantly more often in patients with PADP above 20 mm Hg but were less valuable in predicting pulmonary artery hypertension. RVSTI seem to be more useful than the other echocardiographic parameters for evaluation of pulmonary artery hypertension and RPEP/RVET appears to be the most reliable of them.

Adolescent↗
PubMed1978

Comparison of the calcium- and magnesium-induced structural changes of troponin--C. A proton magnetic resonance study.

Previous proton magnetic resonance studies of the effects of Ca(II) on the structure of rabbit skeletal muscle troponin--C have shown that Ca(II) binding to the two high affinity sites of troponin--C both directs and stabilizes the folding of much of the structure. Ca(II) binding by the two low affinity sites of troponin--C causes changes in the environment of largely hydrophobic residues. We have now examined the structural changes caused by Mg(II) and by Ca(II) in the presence of excess Mg(II). Successive addition of Mg(II) to metal-free troponin--C leads to broadly similar, but not identical, structural changes to those previously assigned to Ca(II) binding at the high affinity sites. None of the changes previously assigned to Ca(II) binding to the low affinity sites was observed. Since Mg(II) does not bind to the low affinity sites, these results confirm the previous assignments. The spectral differences between Mg(II) and Ca(II) show that the degree of backbone folding and interactions between a group of hydrophobic residues (one or more Val, Leu, Ile; two or more Phe) are different for the two cations. In the presence of excess Mg(II), at a molar ratio that may exist in vivo (approx. 40 : 1 mol ratio Mg(II): Ca(II), titration with Ca(II) leads to a displacement of Mg(II) and to all the structural changes previously observed for Ca(II) alone. However, in the presence of Mg(II) the distinction between high and low affinity sites is blurred as judged by the overlap of the spectral changes associated with each of the binding sites. This result, together with the observation that Mg(II) promotes structural changes different from Ca(II), suggests a structural basis for the observation that the Ca(II) threshold for the activation of tension in some myofibrils is increased in the presence of high Mg(II) concentrations.

Animals↗