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Biomedical subjects

A M Souza

Publications and source records attributed to A M Souza.

17 recordsLinked to original sources
PubMed2006

Defect analysis in natural quartz from Brazilian sites for ionising radiation dosimetry.

The impurity-related point defects and the dosimetry properties of quartz irradiated with gamma- and X-rays doses were investigated for natural crystals taken from different geologies. The specimens were initially irradiated with gamma particles from (137)Cs to determine the sensitivity and repeatability of thermoluminescence (TL) emission at approximately 503 K. The dose response was investigated in the range 1-20 mGy. The energy dependence was considered in the range 16-65 keV with X rays and with gamma rays from 137Cs and 60Co. It was found that quartz material from two geologies exhibit a linear relationship between TL intensities and absorbed doses with high angular coefficients. Its sensitivities are higher than that found for LiF TLD-100 dosemeters irradiated in the same conditions. The results were discussed in relation to pre-existing impurity contents and the formation of Al-hole centres.

Brazil↗
PubMed2005

Recombinant human thyrotropin as adjuvant in the treatment of multinodular goiters with radioiodine.

The use of 131I in the treatment of multinodular goiters (MNG) is well established. We evaluated the effect of 30 microCi 131I (1.11 GBq) in 18 patients with MNG with the aid of two injections of 0.1 mg recombinant human TSH (rhTSH), given on d 1 and 2. A dose of 30 microCi 131I was given on d 3. TSH, T3, free T4, and thyroglobulin were measured on d 1, 2, 3, 5, 10, 30, 60, 90, and 180, and antithyroid antibodies were measured on d 1, 30, 90, and 180. Twenty-four-hour 131I uptake measured 1-3 months before rhTSH increased from 12.3 +/- 6.2 to 53.5 +/- 10.9% (P < 0.0001), free T4 from 1.3 +/- 0.2 to peak 3.2 +/- 1.1 ng/dl levels (P < 0.0001), T3 from 113.9 +/- 35.0 to peak 332.2 +/- 123.0 ng/dl levels (P < 0.0001), TSH from 0.76 +/- 0.71 to peak 18.9 +/- 5. 3 mU/liter levels (P < 0.0001), and thyroglobulin from 280.9 +/- 370.0 to peak 1838.5 +/- 1360.7 ng/dl levels (P = 0.001). Painful thyroiditis (33%) and mild thyrotoxicosis (39%) constituted minor side effects. There were no changes in echocardiographic parameters, done before and after rhTSH administration, on d 3. Hypothyroidism developed in 65%. Mean goiter size, measured by computed tomography, decreased from 97.9 +/- 45.4 to 65.5 +/- 47.3 ml (P < 0.0001; reduction: 39 +/- 19%) after 6 months. We conclude that rhTSH is a safe and efficient therapeutic tool in the treatment of MNG allowing the use of outpatient therapeutic 131I doses.

Aged↗
PubMed2005

Evaluation of the effect of aqueous extract of Croton urucurana Baillon (Euphorbiaceae) on the hemorrhagic activity induced by the venom of Bothrops jararaca, using new techniques to quantify hemorrhagic activity in rat skin.

Aqueous extracts of Croton urucurana (Sangra D'agua), a plant popularly considered a cicatrizant, were analyzed for anti-Bothrops jararaca venom activity. The plant extracts antagonized the hemorrhagic activity of the venom and proanthocyanidins were involved in this activity. Two new methods for the quantification of hemorrhagic activity evoked by bothropic venoms were employed. The first consists of graphic computer analysis of the hemorrhagic halo evoked in rats by dorsal intradermic administration of venom. The second method involves quantification of the hemoglobin present in the hemorrhagic halo. Based on the results, we suggest that these methods, easily implemented in the laboratory routine, allow for quantification of venom-induced hemorrhagic activity. In addition, this study demonstrates that the rich extracts of proanthocyanidins are powerful inhibitors of bothropic venom metalloproteinases.

Animals↗
PubMed2000

Prevalence of equine herpesvirus type 1 latency detected by polymerase chain reaction.

In this study, an improved polymerase chain reaction (PCR) was used for detection of DNA of latent EHV-1 strains from several sources. Three pairs of oligonucleotide primers spanning fragments of 333 bp, 226 bp and 268 bp of the thymidine kinase (tk) gene, and one primer pair spanning 225 bp of the glycoprotein C (gC) gene were used in specific amplifications. Primers for EHV-4 PCR were also designed. Restriction digests with TaqI confirmed the identity of tk PCR fragments from EHV-1. The sensitivity to detect PCR products was further improved by visualisation in silver-stained acrylamide gels. PCR assays were applied to 267 samples including pools of tissue, peripheral blood leukocytes (PBL) and nasal swabs of archived, farms and abattoir specimens from a total of 116 animals. The EHV-1 DNA was found in 88% of the analysed samples. The prevalence of the EHV-1 latent or persistent form in adult horses was similar to others reports but found higher than previously described in foetuses and young foals. EHV-4 latency was not detected in the Brazilian studied specimens.

Animals↗
PubMed1997

Influence of acetylator phenotype on the haematological and biochemical effects associated with dapsone in leprosy patients.

Methaemoglobinaemia and haemolytic anaemia were the principal side-effects observed in 30 leprosy patients undergoing long-term treatment with dapsone as a single drug or as part of multidrug therapy. Hepatic, pancreatic and renal evaluations showed no relevant clinical changes. Since N-acetylation is a major metabolic pathway for dapsone, slow acetylation phenotype may be a risk factor for the development of these reactions. To confirm this hypothesis we correlated acetylator phenotype and the haematological and biochemical effects induced by dapsone. No excess proportion of slow acetylators was found. We conclude that slow acetylators are not at greater risk of developing haematological side-effects of dapsone than fast acetylators.

Blood Cell Count↗
PubMed1997

[Ebstein's anomaly in the elderly].

A case of a 62-year-old patient with Ebstein's anomaly is presented. Despite the severe anatomical abnormalities, he was asymptomatic until 61 years of age. Anatomic aspects, clinical features and the diagnostic techniques used are analyzed.

Ebstein Anomaly↗
PubMed1997

Iron deficiency anemia in children: prevalence and prevention studies in Ribeirão Preto, Brazil.

Iron deficiency and ferropenic anemia are, certainly, the most prevalent and specific nutritional problems in Brazil. The Ribeirão Preto region is no exception to it. A large prevalence of iron deficiency/anemia is found, mainly in the age group 6-24 months. In spite of the fact that several aspects of its physiopathology are known it is a very difficult problem to be solved. Many approaches and alternatives for their prevention have been tried but we are far from controlling the situation. Several studies carried out at the Medical School of Ribeirão Preto, University of São Paulo, Brazil have shown this high incidence of iron deficiency and iron anemia among infants and preschool children. The importance of iron supplementation to preterm, premature and normal infants was pointed out. The possibility of use of iron complexes to prevent iron deficiency, besides the usual ferrous sulfate, was shown. Several community studies proved the feasibility of distribution and intake of iron as supplements or fortification of carriers as alternatives to prevent iron deficiency.

Anemia, Iron-Deficiency↗
PubMed1993

Dengue in the south-eastern region of Brazil: historical analysis and epidemiology.

The aim of the study is an historical analysis of the work undertaken by the Public Health organizations dedicated to the combat of the Aedes aegypti, as well as an epidemiological study of persons with unexplained fever, with a view to evaluating the occurrence of dengue within the population. The Mac-Elisa, Gac-Elisa, hemagglutination inhibition, isolation and typage tests were used. Organophosphate intoxication in agricultural workers was also assessed by measuring concentrations of seric cholinesterase. A sera samples of 2,094 were collected in 23 towns, and the type 1 dengue virus was detected in 17 towns and autochthony was confirmed in 12 of them. The cholinesterase was measured in 2,391 sera samples of which 53 cases had abnormal levels. Poisoning was confirmed in 3 cases. Results reveal an epidemic the gravity of which was not officially know. The relationship between levels of IgM and IgG antibodies indicates the outbreak tendency. The widespread distribution of the vector is troubling because of the possibility of the urbanization of wild yellow fever, whereas the absence of A. aegypti in 2 towns with autochthony suggests the existence of another vector. Since there is no vaccine against dengue, the combat of the vector is the most efficient measure for preventing outbreaks. The eradication of the vector depends on government decisions which depend, for their execution, on the organization of the Health System and the propagation of information concerning the prevention of the disease using all possible means because short and long term results depend on the education and the active participation of the entire population.

Aedes↗
PubMed1992

[Factors involved in the prognosis of walking in cerebral paralysis].

With the objective of studying the prognosis for walking in children with cerebral palsy a retrospective survey of 100 children being treated at the Associação de Assistência à Criança Defeituosa was made during the period from 1979 to 1988. The following parameters were analysed: (1) degree of motor dysfunction; (2) age of acquisition of sitting balance; (3) function of upper limbs; (4) degree of mental retardation; (5) presence of primitive reflexes. All the above parameters were analysed with respect to the capability of children acquiring or not walking. The results of our study show that the following factors are indicative of bad prognosis for walking: (1) severity of motor dysfunction; (2) acquisition of sitting posture after 3 years old; (3) precarius function of upper limbs; (4) severe mental retardation associated with severe physical deficiency. Clinical evaluation of primitive reflexes did not reveal direct relation to the walking prognosis.

Adolescent↗
PubMed1984

Isolation and convulsant effect of the 'insulin-like' proteins from the pancreas of the Brazilian opossum Didelphis albiventris.

An opossum pancreatic insulin-like protein fraction was obtained at pH 5.2 which has high electrophoretic mobility. At pH 8.2, another pancreatic insulin-like protein fraction was obtained with low electrophoretic mobility. Isoelectric focusing studies showed that the high molecular weight protein has a pI value 8.35 and the low molecular weight protein has pI value of 3.9 when used at pH range between 3.5-10.0. The purified high and low molecular weight positive aldehyde-fuchsin proteins induced convulsions when administered subcutaneously to mice.

Animals↗
PubMed1983

Isolation and convulsivant effect of the "insulin-like" protein obtained from the exocrine pancreas of Bradypus tridactylus L.

1. A pancreatic insulin-like protein fraction with low electrophoretic mobility showing high molecular weight is present. 2. Isoelectric focussing studies showed that the high molecular weight protein has a pI about 7.4 when used at a pH range between 3.5 and 8.0. 3. The partially purified aldehyde-fuchsin positive high molecular weight protein fraction gave a positive effect for the convulsivant test in mice. 4. A high molecular weight insulin-like protein in pancreatic juice was found. 5. Insulin was found by radioimmunoassay in the basal and post stimulation pancreatic juice.

Animals↗
PubMedDate not supplied

Migraine in childhood and adolescence. A critical study of the diagnostic criteria and of the influence of age on clinical findings.

We studied 253 children aged <15 years. Phase 1 included 193 children with migraine (1.1 and 1.2) divided into two groups (<10 and > or = 10 years). We studied the relationship between age and migraine type, headache characteristics, and associated symptoms of the International Headache Society (IHS) definition. A higher frequency of migraine with aura, pulsatile quality, and unilateral location was observed in older children. In phase 2 we studied 176 children with headache (excluding migraine with aura), comparing diagnostic criteria, definition items, sensitivity, and specificity. The results showed that item B of the definition was the most frequent cause of exclusion in the 1.7 diagnostic group. Compared with Vahlquist and the IHS, the Prensky criteria were the most sensitive. Sensitivity was >70% for pain of moderate/severe intensity, duration between 2 and 48 h, isolated photophobia, isolated phonophobia, and aggravation with physical activity. Specificity was >70% for nausea, vomiting, phonophobia and photophobia, isolated photophobia, aggravation with physical activity, and isolated phonophobia. Based on three alternative definitions, each modifying one item of the IHS definition, the sensitivity and specificity of these alternative definitions were compared with the "extended" criteria (children with migraine without aura and migrainous disturbance, according to the IHS criteria, grouped together). Exclusion of headache duration increased sensitivity by 10%, compared to restrictive IHS criteria, without decreasing specificity.

Adolescent↗