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A Gouveia

Publications and source records attributed to A Gouveia.

17 recordsLinked to original sources
PubMed2006

Effects of mercury intoxication on the response of horizontal cells of the retina of thraira fish (Hoplias malabaricus).

Methyl mercury (MeHg) is highly neurotoxic, affecting visual function in addition to other central nervous system functions. The effect of mercury intoxication on the amplitude of horizontal cell responses to light was studied in the retina of the fish Hoplias malabaricus. Intracellular responses were recorded from horizontal cells of fish previously intoxicated with MeHg by intraperitoneal injection (IP group) or by trophic exposure (T group). Only one retina per fish was used. The doses of MeHg chloride administered to the IP group were 0.01, 0.05, 0.1, 1.0, 2.0, and 6.0 mg/kg. The amplitudes of the horizontal cell responses were lower than control in individuals exposed to 0.01 (N = 4 retinas), 0.05 (N = 2 retinas) and 0.1 mg/kg (N = 1 retina), whereas no responses were recorded in the 1.0, 2.0, and 6.0 mg/kg groups. T group individuals were fed young specimens of Astyanax sp previously injected with MeHg corresponding to 0.75 (N = 1 retina), 0.075 (N = 8 retinas) or 0.0075 (N = 4 retinas) mg/kg fish body weight. After 14 doses, one every 5 days, the amplitude of the horizontal cell response was higher than control in individuals exposed to 0.075 and 0.0075 mg/kg, and lower in individuals exposed to 0.75 mg/kg. We conclude that intoxication with MeHg affects the electrophysiological response of the horizontal cells in the retina, either reducing or increasing its amplitude compared to control, and that these effects are related to the dose and/or to the mode of administration.

Animals↗
PubMed2003

Investigation of the onset and development of forward scattering in an underdense plasma.

We investigate the distortion of a spatial intensity modulation imposed on a 527 nm f/10 probe beam as it transmits through an underdense plasma characterized with Thomson scattering. Combining the measurements with full wave simulations of beam propagation through the entire plasma show that the key features of the data can be reproduced using the Kaiser thermal transport model.

Journal Article↗
PubMed2002

K-shell spectroscopy of an independently diagnosed uniaxially expanding laser-produced aluminum plasma.

We present detailed spectroscopic analysis of the primary K-shell emission lines from a uniaxially expanding laser-produced hydrogenic and heliumlike aluminum plasma. The spectroscopic measurements are found to be consistent with time-dependent hydrodynamic properties of the plasma, measured using Thomson scattering and shadowgraphy. The K-shell population kinetics code FLY with the measured hydrodynamic parameters is used to generate spectra that are compared to the experimental spectra. Excellent agreement is found between the measured and calculated spectra for a variety of experimental target widths employed to produce plasmas with different optical depths. The peak emission from the hydrogenic Lyman series is determined to be from a temporal and spatial region where the hydrodynamic parameters are essentially constant. This allows a single steady-state solution of FLY to be used to deduce the electron temperature and density, from the measured line ratios and linewidths, for comparison with the Thomson and shadowgraphy data. These measurements are found to agree well with time-dependent calculations, and provide further validation for the FLY calculations of the ionization and excitation balance for a K-shell aluminum plasma. We also discuss the possible application of this data as a benchmark for hydrodynamic simulations and ionization/excitation balance calculations.

Journal Article↗
PubMed2001

Longitudinal left ventricular function in a population of healthy adults: a tissue Doppler imaging study.

BACKGROUND: Longitudinal left ventricular function is a major determinant of global ventricular function and is probably more sensitive than radial function in the detection of disease. Tissue Doppler imaging of the mitral annulus allows the study of longitudinal left ventricular function. METHODS: Forty-five healthy volunteers divided into two groups (younger and older than 45 years) were studied with pulsed tissue Doppler imaging of the 4 sides of the mitral annulus (septal, lateral, inferior, anterior) in 4 and 2 apical chamber views. In each wave (systolic-s, rapid filling-e, atrial contraction-a) we analyzed velocities, time intervals and velocity-time integrals, as well as heterogeneity and asynchrony indexes. Data were compared between the different sides in each group, between groups and with conventional Doppler data. RESULTS: In contrast to the septal side, the lateral side of the annulus shows higher velocities and velocity-time integrals of the s and e waves, with non-significantly shorter isovolumic relaxation time and shorter time to peak e. There is functional agreement between the lateral and inferior sides versus the septal and anterior sides of the annulus. Most systolic parameters remained unchanged with aging; however, aging was associated with decreased e velocity, increased a velocity and inverted e/a ratio. The relation between s and fractional shortening also did not change with aging. Annular isovolumic contraction time and isovolumic relaxation time were shorter than their respective global time intervals. CONCLUSIONS: This study shows that there are physiological differences in velocities, time intervals and velocity-time integrals between the 4 sides of the mitral annulus, reflecting physiological heterogeneity and asynchrony, and that some of these parameters are age dependent. These data also contribute to a better understanding of longitudinal left ventricular function and may be useful in future studies as reference values in control groups.

Adult↗
PubMed1999

Conserved sequence motifs involving the tat reading frame of Brazilian caprine lentiviruses indicate affiliations to both caprine arthritis-encephalitis virus and visna-maedi virus.

The sequence variation in small ruminant lentiviruses from Brazilian herds of milking goats was sampled in a representative region of the pol gene and in a region including the entire tat open reading frame. Clones were amplified from cDNA derived from virus produced in vitro using primers targetting conserved sequences of the pol gene. Iterative sequencing of clones indicated that animals from two herds in the Minas Gerais area were infected by a caprine arthritis-encephalitis virus (CAEV)-like virus and that individual animals carried variant virus populations. Sequences derived from an infected goat from a herd in Pernambuco showed no nucleic acid variation and were distant from the CAEV-type sequence but marginally closer to ovine visna-maedi virus (VMV) sequences. Sequences amplified from a region including the tat gene, amplified with a common upstream primer within the vif coding region and different downstream primers because of the local divergence between CAEV- and VMV-type sequences, confirmed the affiliation of the Minas Gerais sequences to CAEV and indicated that the Pernambuco isolate was indeed related to VMV, which had not previously been reported to cause natural caprine infection. The overlap between the vif and tat open reading frames clearly distinguished between CAEV-like small ruminant lentiviruses, which shared eight common nucleotides, and the VMV group, where the overlap was reduced to a single base; the final adenine of the vif terminator (TAA) is the initial adenine of the presumptive tat initiator codon. This may be useful for epizoological tracing of the origin of outbreaks.

Amino Acid Sequence↗
PubMed1999

Role of myocardial ischemia and left ventricular wall motion abnormalities as contributory factors in the genesis of exercise-induced ST-segment elevation in Q-wave myocardial infarction.

In patients with a previous myocardial infarction, controversy exists regarding the significance of postexercise ST-segment elevation in the infarct-related leads. Although usually admitted to be a sign of left ventricular dysfunction or myocardial aneurysm, other studies however have related this finding to transient myocardial ischemia and to the presence of jeopardized but viable myocardium in the infarct area. The aim of the present study was to assess the significance of postexercise ST-segment elevation in Q-wave leads as a marker of transmural ischemia or left ventricular dysfunction in 36 consecutive patients, 16 with exercise-induced ST-segment elevation in infarct-related leads. Patients were evaluated by treadmill exercise testing, coronary angiography and ventriculography, thallium-201 tomographic scintigraphy and radionuclide ventriculography within 3 months of the first myocardial infarction. Sixteen patients (group I) had exercise-induced ST segment elevation and 20 (group II) postexercise inversion, no change or pseudonormalization of the T wave in infarct-related leads. The study showed no difference in infarct-related artery, vessel disease or luminal diameter stenosis in groups I and II. The overall agreement between ST shifts and myocardial perfusion in the infarct area was 30.56% with a kappa coefficient of -0.33 (p = NS). The overall agreement between ST shifts and wall motion abnormalities was 69.44% with a kappa coefficient of 0.39 (p < 0.01), stress-induced ST-segment elevation being associated with severe wall contractile disorders in 85% of the patients. In conclusion stress-induced ST-segment elevation in Q wave leads, although not a marker of wall motion abnormalities, is associated with akinesia or dyskinesia of the left ventricular wall.

Coronary Angiography↗
PubMed1998

Esophageal inflammatory pseudotumor associated with a pseudodiverticulosis cyst: two inter-related lesions?

There are some unusual esophageal lesions, which by their rarity, and location or etiology raise difficult therapeutic decisions for surgeons. In this report, we describe an esophageal inflammatory pseudotumor (IPT) associated with a pseudodiverticulosis cyst in an adult male. We discuss the pathogenic and the anatomopathological aspects of these uncommon associated lesions as well as the treatment of ITP.

Diverticulum, Esophageal↗
PubMed1998

Plasma homovanillic acid and prolactin in systemic lupus erythematosus.

Prolactin (PRL) is an important immunoregulator and might have a role in the pathogenesis of systemic lupus erythematosus (SLE). The regulation of pituitary prolactin secretion is complex and involves a negative feedback process in the hypothalamus, in which dopamine plays the principal role. However, the main source of serum prolactin in lupus patients is still not clearly established. Since homovanillic acid (HVA), the principal metabolite of dopamine (DA), is removed from the brain into the blood, it would indirectly reflect DA metabolism. It is assumed that the turnover of a neurotransmitter can be determined through an analysis of its metabolites. The objective of this study was to analyse plasma samples from SLE patients to see if there were any alterations in neurally functioning DA through its principal metabolite, HVA. We also measured the levels of PRL and compared HVA and PRL with the clinical activity of the disease. Twenty-four SLE patients and fifteen healthy controls were studied. The investigation was done over a period of 3 months. The results of this study show significantly low levels of HVA in lupus patients compared to controls (P < 0.0001). This corresponds to a decrease in dopamine turnover. Hyperprolactinemia was observed in nine patients, and the average level of prolactin in lupus patients was higher than in healthy controls (P < 0.001). For the duration of the study, a significant percentage of variation was observed in the levels of HVA in the clinically active patients (P < 0.05) compared to inactive patients. When PRL was compared in these groups, throughout the study, no significant percentage of variation was observed. The relationship between HVA and PRL in healthy controls was r = 0.47, P = 0.08, and in patients was r = 0.04, P = 0.84. It is suggested that there is a probable association between plasma levels of HVA and PRL in the healthy controls and not in the SLE patients.

Adolescent↗
PubMed1998

[Cardiac troponin-T. Diagnostic efficacy in acute myocardial infarction. Clinical and laboratory assessment].

Cardiac troponin-T is a subunit of the myofibrillar regulatory troponintropomiosin complex, with sufficient specificity to myocardium. In normal conditions it is absent from serum and its presence indicates lesion of the cardiac cells. The authors evaluated the analytical and clinical performance of an immunoassay for cardiac troponin-T, before its introduction in their own laboratory routine. They concluded that the test had good analytical performance, with some difficulties in practicability that can be surpassed by using a rapid bedside test for troponin-T in urgency departments, already approved by FDA in USA and available in Portugal. The diagnostic specificity and sensitivity was better than the one of the classic enzymatic markers for Acute Myocardial Infarction (AMI) but it is necessary to establish clear clinical protocols that allow its use in AMI.

Biomarkers↗
PubMed1998

Post-exercise electrocardiographic alterations, ST-segment elevation and QTc changes in patients with recent myocardial infarction.

UNLABELLED: Stress-induced ST-segment elevation and a prolongation or no change of the QTc ratio (corrected QT interval for heart rate) at maximal exercise in the infarct leads have been associated with the presence of residual myocardial ischemia in the infarct zone. The aim of this study was to test the agreement between stress-induced ST-segment elevation and post-exercise QTc changes in infarct leads, in 36 consecutive patients, studied by coronariography, radionuclide ventriculography and thallium-201 scintigraphy, within 3 months of the acute myocardial infarction. Sixteen patients (Group I) had exercise-induced ST-segment elevation in the infarct leads and 20 did not (Group II). The study showed no significant difference between severity of vessel disease and occlusion, prevalence of the infarct related artery or left ventricular dysfunction in Group I and II. No agreement between ST-segment shifts and myocardial perfusion in the infarct zone was found. Resting wall motion abnormalities were more severe in Group I than in Group II (p < 0.01). In the total of the 36 patients there was no agreement between ST-segment shifts and QTc-variations. The study showed agreement between QTc changes and myocardial perfusion in the infarct area (K = 0.64) (p < 0.001). CONCLUSION: This study showed no relation between post-exercise ST elevation and post-exercise QTc variations in Q wave leads. QTc variations at the end of exercise in the infarct related leads identified residual ischemia. Exercise ST segment elevation, although not a marker of ischemia, is associated with more severe wall motion abnormalities in the infarct zone.

Coronary Angiography↗
PubMed1997

Comparison between dobutamine echocardiography and thallium-201 scintigraphy in detecting residual stenosis, ischemia, and necrosis in patients with prior myocardial infarction.

BACKGROUND: Following the first attempts to detect myocardial ischemia with two-dimensional echocardiography stress testing, pharmacologic stress using dobutamine infusion has become an alternative to echocardiography exercise testing for evaluation of coronary artery disease. It has been shown that stress echocardiography has a diagnostic accuracy similar to that of an exercise thallium test. Other studies, however, indicated that radionuclide myocardial perfusion imaging was more sensitive than exercise or pharmacologic stress echocardiography for detection of ischemia or jeopardized myocardium. HYPOTHESIS: The aim of the present study was to determine the ability of dobutamine stress echocardiography in comparison with thallium-201 scintigraphy to identify multivessel disease and the presence of myocardial scar and ischemia in 60 consecutive patients who suffered a first myocardial infarction (MI). METHODS: Patients were evaluated by coronary angiography and ventriculography, thallium-201 (201TI) tomographic scintigraphy, and dobutamine echocardiography within 3 months of a first MI. Forty-seven had Q-wave MI and 13 had non-Q-wave MI. Eleven patients were excluded from final analysis-7 because of failure to achieve target heart rate in spite of the use of atropine, and 4 because of high blood pressure following the infusion of dobutamine. RESULTS: Dobutamine echocardiography showed an overall sensitivity of 43% for detection of coronary artery lesions of 50-74% diameter stenosis and 201TI scintigraphy showed a sensitivity of 71%. For detection of lesions of > or = 75% diameter stenosis, dobutamine echocardiography showed a sensitivity of 52% and 201TI a sensitivity of 70%. Overall agreement between wall motion and myocardial perfusion for detection of necrosis and/or ischemia in the infarct area was 40.4% with a kappa coefficient of 0.09 (p = 0.13). For detection of ischemic myocardium outside the infarct zone, overall agreement was 78.6% with a kappa coefficient of 0.49 (p < 0.0001). CONCLUSION: Dobutamine echocardiography results showed a lower sensitivity than myocardial perfusion images in predicting multivessel coronary artery disease, and there was poor agreement between both methods in identifying necrosis or ischemia.

Coronary Angiography↗
PubMed1997

[Coronary artery disease, myocardial perfusion and ventricular function in Q-wave and non-Q-wave myocardial infarcts].

Controversy remains in considering non-Q wave myocardial infarction (NQMI) a distinct pathophysiological entity of Q wave myocardial infarction (QMI). In order to analyze the severity of coronary artery disease, extension of myocardial scar or myocardial ischemia and ventricular function, 78 consecutive patients with QMI and 32 with NQMI, mean age 55.4 +/- 8.5, not submitted to thrombolytic therapy, were studied. Coronary angiography, exercise thallium scintigraphy and radionuclide ventriculography were performed in all at least within 3 months of a prior myocardial infarction. In the present study the occurrence of QMI was significantly more frequent in older patients than NQMI. There was no prevalence of occlusion either in the right, left circumflex or left anterior descending coronary arteries in both groups. Ejection fraction, degree of occlusion and presence of collateral circulation showed an equal prevalence in QMI and NQMI patients. A higher incidence of multivessel disease was found in NQMI that had less necrosis than QMI patients. The prevalence of exercise induced thallium-201 redistribution defects within the infarct zone was substantially higher and involved more scar segments in NQMI patients. Physiological and clinical consequences of coronary thrombosis depends on the size and the number of diseased arteries, the approach the pathophysiologic consequences of coronary disease in terms of fractal structure has been suggested. A pronounced heterogeneity in regional myocardial blood flow in a fractal branching arterial network may be responsible for the pathophysiologic differences of coronary thrombosis between Q-wave and non Q-wave infarction.

Adult↗
PubMed1989

[Large trials in hypertension].

Arterial Hypertension is an important public health problem due to its high prevalence, and consequences in terms of strokes, particularly in Portugal. The benefits of medical treatment of moderate and severe arterial hypertension are well documented. Some doubt persist in relationship to the indications to treat mild hypertension. This arises from the contradictory results of the great clinical trials. Some recent data suggests that the use of thiazide in low dosage, and cardioselective betablockers, in smokers, offers some hope.

Cerebrovascular Disorders↗
PubMedDate not supplied

[Prospective study of duodenal ulcer. Analysis of prognostic factors].

We conducted a prospective clinical trial of 154 patients with duodenal ulcer disease, which was divided in two different steps: healing phase and post-healing phase. In the first phase, the patients were randomly assigned to treatment with H2 blockers (Ranitidine 300 mg or Famotidine 40 mg), in a single bedtime dose. Endoscopy was performed after 4 and 12 weeks of treatment and the healing rate was 70% and 90%. There were no significant differences between the two drugs. After 12 weeks of treatment there were sixteen patients with non-healed duodenal ulcer, considered as refractory duodenal ulcer disease, in which we started therapy with a double dose of H2 receptor antagonists or sucralfate (4 gr/day). Endoscopic follow-up after 12 weeks of this regimen revealed ulcer healing in about half of them; the cummulative healing rate in 6 months was 96.4%. Persistent lesions after 6 months of follow-up were found in 5 patients. Omeprazole 40 mg, single dose, was given and all of them were healed during the first 4 weeks of treatment. In the second phase, 137 patients healed during the first 3 months of treatment, were followed for 12 months and randomized in two groups: 61, with maintenance therapy--ranitidine 150 mg or famotidine 20 mg; 76, without treatment. In the patients without maintenance therapy, the recurrence rate was significantly higher (p less than 0.55), than in the group with maintenance therapy. In this group several parameters were evaluated--clinical, biochemical and psychosocial--to try to identify some prognostic markers of healing, relapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Prevalence of chronic hepatic disease in Portugal. Apropos of a review carried out in a hepatology unit].

UNLABELLED: The chronic elevation of Aminotransferases is one of the most frequent indications for percutaneous Liver Biopsy (LB). From a retrospective study of LB performed in the Hepatology liver Unit of Santa Maria Hospital, between 1989 and 1993, we correlated the histologic diagnosis with the etiology of liver disease, sex, age and the Aspartate aminotransferase/Alanine aminotransferase (AST/ALT) and Gama-Glutamyl transpeptidase (gamma GT) index in patients with chronic liver test abnormalities. 790 LB were reviewed retrospectively, of patients aged between 11 and 78 years, 68% males and 32% females. The most common etiology was Hepatitis C (34.6%), followed by Hepatitis B (20.1%) and alcohol (15.8%). Autoimmune diseases (Primary Biliary Cirrhosis and Autoimmune Hepatitis) were present in 3% of cases, and metabolic liver diseases in 1.4%. The distribution by sex revealed a predominance of Hepatitis C in both, alcoholic liver disease being more frequent in males (21.5% vs 3.9%). The main histological diagnoses were Chronic Active Hepatitis (27.2%), Liver Cirrhosis (19.5%), Steatohepatitis (9.5%) and minor lesions (24.6%). In alcoholic liver disease, 47.2% had Liver Cirrhosis and 16% Steatohepatitis; in Hepatitis B, Liver Cirrhosis was found in 12.6% and in Hepatitis C in 11.4%. Liver Cirrhosis had a prevalence between the 4th and 6th decade of life (82%) with a peak incidence in the 5th, and appeared earlier in Hepatitis B and later in Hepatitis C. The prevalence between sexes was similar. The main etiology of Liver Cirrhosis was alcohol (38.3%). The gamma GT index was greater in alcoholic liver disease (average 4.1) and was nearly twice in Hepatitis C than in Hepatitis B (1.7 vs 0.8). CONCLUSIONS: 1) Hepatitis C in our Hepatology Unit was the main indication for Liver biopsy. 2) The prevalence of alcoholic liver disease is greater in males, being the main etiology of Liver Cirrhosis. 3) The progression to Liver Cirrhosis seems to be similar in Hepatitis B and C. 4) The progression to Liver Cirrhosis is similar in both sexes, being dominant in the 5th decade of life. 5) The progression to Liver Cirrhosis is earlier in Hepatitis B than in Hepatitis C. 6) A gamma GT index elevation, without alcohol abuse, is suggestive of Hepatitis C. 7) Autoimmune and metabolic liver diseases seem to be rare in Portugal.

Adult↗
PubMedDate not supplied

[The risk of seroconversion in surgeons of the hepatitis B, hepatitis C and human immunodeficiency viruses (in a specific surgical population)].

The prevalence of hepatitis B surface antigen (HBs Ag) and antibody to hepatitis C virus (HCV) and human immunodeficiency virus (HIV) was determined in the serum specimens of 288 patients treated surgically in the orthopaedic department of an urban public teaching hospital. The cumulative risk of HBV, HCV and HIV seroconversion for an orthopaedic surgeon during the surgical career span was calculated. We found that 1.4%, 3.1% and 1.7% of patients were seropositive for HBsAg, HCV antibody and HIV antibody, respectively. Seropositivity was neither associated with age nor with trauma, whereas male patients had a greater likelihood of seropositivity. Risk factor assessment did not prove to be discriminating in identifying which patients may pose a potential exposure risk. This study supports the concept of universal infection control precautions for orthopaedic surgeons regardless of the patients' risk factor or serologic status.

Adult↗