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Biomedical subjects

J E de Oliveira

Publications and source records attributed to J E de Oliveira.

At least 19 recordsLinked to original sources
PubMed1999

High-yield purification of biosynthetic human growth hormone secreted in Escherichia coli periplasmic space.

A six-step, high-yield purification procedure for the preparation of clinical grade recombinant human growth hormone (rhGH) secreted in bacterial periplasmic space is described. Particular emphasis is given to hormone recovery yields and maximum contaminant host cell elimination. The strategy adopted, in addition to using one precipitation and five chromatographic steps in a particularly efficient sequence, was also based on running E. coli proteins - immunoradiometric assay profiles right after each chromatographic elution. Thus, an overall rhGH recovery higher than 40%, with a final concentration of E. coli proteins below 10 ppm is described for the first time. The accuracy of hGH and total protein quantification, especially in the early steps of the process, and the maximum elimination of hGH-related forms were also studied in detail. For these purposes size-exclusion and reversed-phase HPLC were found to be extremely valuable analytical tools.

Chromatography, High Pressure Liquid↗
PubMed1999

Enrichment of the diet with synthetic and natural sources of provitamin A.

The use of available food rich in provitamin A and retinol as well as fortification of local food are known to result in adequate vitamin A status. In Brazil, several regional foods are known to be good sources of provitamin A such as buriti, several palm oils, mango and others. Improving the consumption of these locally available natural sources of provitamin and vitamin A would cover the needs of the vulnerable population. At the same time fortification of industrialized foods with natural and/or synthetic forms of provitamin A could speed up and fill the gap between requirement and low intake of this vitamin in many parts of the country. This approach has been considered by many as the most effective intervention program to prevent micronutrient deficiencies in developing countries. Our previous studies on the subject have shown that cooking vegetable oil, mainly soybean oil, is a very good alternative vehicle to be fortified and supply vitamin A to the population. Lately we have also enriched the same soybean oil with beta-carotene. Addition of this provitamin A to the oil showed it to be stable when heated at cooking and frying temperatures (retention of 92.4 +/- 6.7% and 65.4 +/- 8.6%, respectively). When rat or human food was prepared with carotene-enriched cooking oil, its bioavailability in experimental animals and absorption in humans were shown to be adequate. An alternative for Brazil, besides adding chemical forms of the vitamin to the cooking oil, would be to mix available carotene-rich palm oil to the soybean oil. There are already regional uses of carotenoid-rich palm oils in the preparation of local dishes in some parts of Brazil and this would facilitate its acceptance by the population. Enrichment of common foods in Brazil, such as soybean oil, with chemical forms of beta-carotene or mixing rich sources of provitamin A can be a good alternative to improve the intake of vitamin A by the Brazilian population.

Animals↗
PubMed1998

On the methods for studying the mechanisms and bioavailability of iron.

Studies of the molecular mechanisms involved in the absorption and bioavailability of iron are important to attempts made worldwide to control the high incidence of iron-associated disorders. The ultimate objective of these studies is to develop methods that are relevant to iron bioavailability and interactions in humans. However, a comprehensive understanding of the chemical and physiologic mechanisms that influence iron bioavailability is necessary to achieve this goal. Initial studies using in vitro and animal models offer the potential for flexibility and manipulation of experimental variables that could provide valuable information toward the understanding and improvement of food iron bioavailability.

Animals↗
PubMed1998

Methionine supplementation of soya products: effects on nitrogen balance parameters.

Soybean protein is one of the best quality foods available. Contribution of soy to human nutrition increases because of its overall positive nutritional profile, low cost, high protein and excellent functional properties. Addition of methionine to rat soybean diets improve biological value of soy protein. Few studies on methionine fortification of soya protein were carried in infants, but fortification of baby formulas with this amino acid is usually found. This study was carried out to demonstrate in malnourished children that the effect of methionine supplementation of soya milk and soy isolated protein, as well as to compare with their results to cows' milk. A total of 30 malnourished children, 1 to 3 years old, admitted to our metabolic unit and distributed in groups of 6 children were studied. They were fed experimental formulas with cows' milk, soya milk, soya milk plus methionine, soya isolated and soya isolated plus methionine. Nutrient compositions of formulas were calculated to be similar to mothers' milk. DL-methionine, 1.5 g per 100 g protein content was added to soya milk and soya isolated formulas. Two nitrogen balances, 3 days each, were carried out. Fecal and urinary nitrogen, serum proteins, creatinine and urea in serum and urine were followed during the study. Results showed differences of intake and retention of nitrogen between some of the groups, but there were no statistically significant differences on protein absorption in the groups. No differences were demonstrated in serum proteins, total nitrogen and other serum and urine parameters analyzed. Cows' milk fed children presented the highest nitrogen retention in both balance studies. The addition of methionine to the soya milk formula increased the nitrogen retention, not reaching the cows' milk levels and did not have the same effect when added to the isolate soy protein.

Analysis of Variance↗
PubMed1997

Analysis of recombinant human growth hormone directly in osmotic shock fluids.

An isocratic reversed-phase high-performance liquid chromatography (RP-HPLC) method for the determination of human growth hormone (hGH) directly in osmotic shock fluids is described. This methodology allows an initial rapid evaluation of the quality and quantity of hGH being secreted in the bacterial periplasmic space right after, or even during fermentation. Considering that RP-HPLC does not identify size isomers, these were determined via a parallel run of the same osmotic shock fluid on high-performance size-exclusion chromatography, coupled with radioimmunoassay, of the eluted fractions. The methodology provides a complete picture, within 24 h from the beginning of the fermentation process, of the recombinant protein being produced with respect to its activity, identity, yield, and hGH-related contaminants. These latter include sulfoxide and desamido derivatives, dimer and high-molecular-mass forms.

Chromatography, High Pressure Liquid↗
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↗
PubMed1996

Iron fortification of domestic drinking water to prevent anemia among low socioeconomic families in Brazil.

Iron deficiency anaemia is a most common micronutrient deficiency affecting mostly the low socioeconomic populations of the developing world. The objective of this study was to evaluate the feasibility of iron fortification of household drinking water to prevent iron deficiency anaemia among members of the low socioeconomic families of Southern Brazil. A total of 21 low socioeconomic families representing 88 subjects including 1-6 years old children whose haemoglobin level was between 10 and 12 g/dl were selected to participate in this study. Nine families in the control group were supplied with placebo solution and 12 families in the experimental group were supplied iron solution with ascorbic acid to be added to their domestic drinking water over a period of 4 months. The feasibility and acceptability of iron fortified drinking water was assessed through home visits and questionnaires. Blood samples were collected at the beginning and after 4 months of the study for the determination of haemoglobin and serum ferritin levels. The results of this study indicated that iron fortified drinking water was well received by the low socioeconomic families and that it was effective in improving the haemoglobin and serum ferritin levels. It can be concluded from this study that iron fortification of household drinking water is a simple and effective alternative for developing countries along with other technological approaches to iron fortification of foods.

Adult↗
PubMed1994

[Calculation of recommendations regarding protein intake: their application to preschool, school students and adults taking Brazilian foods].

The recommendations for protein consumption depend on the essential amino acid and total nitrogen content of a diet, and food digestibility. International recommendations are based on egg or milk proteins. However, populations eat different food mixtures. Brazilians use rice and beans as their main protein food source. This study presents different Brazilian diets, with variable amount of rice and beans. The results show that for each diet there is a different amount of protein recommended. Pre-school children, for example, must receive from 1.15 to 1.77 g/protein/day, depending on the mixture of their dietary protein intake. Besides the diet protein's quality and quantity, the total food intake and presence of other essential nutrients, such as iron, calcium and vitamin C has also to be considered. The correct protein recommendation with respect to a diet or a mixture of food, should take into consideration: digestibility, total nitrogen, essential amino acids, presence of others nutrients and weight of food consumed.

Adult↗
PubMed1993

Vitamin C load test in elderly subjects.

Ascorbic acid fasting serum levels and levels after a test dose were carried out in a group of elderly subjects: nine men with 70 +/- 6 years and six women 74 +/- 7 years old. They live in the same old folks home and ate similar food. Their ascorbic acid intake was found to be around 20 mg/day. Fasting serum levels found lower values in the women. A load test showed a small increase in the hourly samples, supporting low tissue reserves of the vitamin. Factors such as low intake, absorption, metabolism, body mass and/or excretion of the vitamin in elderly population could explain these results. A marginal vitamin C deficiency is believed to be present in the group and extra ascorbic acid food supply seems to be recommended for these subjects.

Aged↗
PubMed1991

Plasma amino acid patterns in alcoholic pellagra patients.

Plasma amino acid concentrations in 33 male alcoholic patients with pellagra (age 20-68 years) were compared with those in 17 healthy male subjects (age 20-45 years). Pellagra diagnosis was made on the basis of the typical clinical skin picture, and low urinary excretion of N'methylnicotinamide and N'methyl-2-pyridone-5-carboxamide (reduced by 70 and 80%, respectively, compared with controls). There were significant differences in body mass index, creatinine/high index and serum albumin between the two groups, indicating that besides pellagra the alcoholic patients had some degree of malnutrition. Of 17 plasma amino acids measured, the following had significantly lower concentrations in the pellagrins: tryptophan (3.65 vs 5.93 mumol/dl, pellagrin vs control), isoleucine (6.31 vs 11.13), leucine (11.54 vs 24.19), lysine (16.25 vs 34.47), methionine (2.61 vs 4.22), phenylalanine (5.71 vs 9.23), threonine (13.29 vs 26.81), valine (17.60 vs 41.06), alanine (42.54 vs 70.87), arginine (5.87 vs 10.09), tyrosine (5.57 vs 9.30). Glutamic acid was significantly higher in the pellagrins (18.45 vs 9.49). There was no difference between the groups of aspartic acid, glycine, histidine, proline and serine concentrations. It is concluded that pellagra is an important factor influencing the amino acid profiles in these patients. This finding should be taken into account when using plasma amino acid levels to assess the clinical status of the pellagrin.

Alcoholism↗
PubMed1990

Nutritional needs assessment of rural agricultural migrants of southern Brazil: designing, implementing and evaluating a nutrition education program.

A nutritional needs assessment was conducted among rural agricultural migrant women (target group) and children (less than 5 years). The study was conducted in Vila Diogo, a slum located on the periphery of Nuporanga, a village in Sao Paulo state, Brazil. A nutrition education program was designed on the basis of evidence obtained from demographic/socioeconomic information of the study population and a nutritional needs assessment of women (target group) and children less than 5 years of age. The nutritional needs assessment consisted of anthropometry, dietary assessment, and nutrition knowledge, attitudes, and beliefs questionnaires. Formative and summative evaluation of the nutrition education program, using appropriately selected criteria and comparisons of nutrition knowledge scores before and after the program, were used to determine program effectiveness. Major findings of the study were: Diets of Vila Diogo residents were generally simplistic, consisting primarily of rice, beans, and coffee with sugar. Vila Diogo women appeared to be at a relatively high risk for vitamin A, iron, calcium, ascorbic, and riboflavin deficiencies, based on comparisons of 24-hour dietary intake data with FAO recommendations. Children (2-5 years) appeared at high risk for vitamin A, iron, and ascorbic acid deficiencies, based on comparisons of 24-hour dietary intake data with FAO recommendations. All children less than 5 years of age had been breast-fed at birth, but more than one half of children had been weaned by the third month. Infant feeding practices during fever and diarrhea were nutritionally detrimental. Women generally recognized a relationship between dietary intake during pregnancy and fetal nourishment. Using weight-for-height index, a significant number of women were probably undernourished; a small percentage of women, however, were overweight or obese. Although children less than 5 years of age did not generally appear malnourished, a relatively large number were stunted in growth. Although Vila Diogo women reported many food taboos during various physiological states (menstruation, pregnancy, immediately post partum, lactation), relatively few food taboos had potentially negative nutritional consequences. For women who participated in the nutrition education program, nutrition knowledge scores after the program showed improvement which was statistically significant at alpha = 0.05, using Wilcoxon signed rank test.

Brazil↗
PubMed1990

Progress in the diagnosis of hypovitaminosis A: clinical and biochemical correlations.

Hypovitaminosis A is a widespread problem, especially among preschool children in many parts of the world. According to the World Health Organization (WHO) estimates, about 100,000 children become blind every year, and many are dying due to vitamin A deficiency while millions of others are suffering from other consequences of vitamin A deficiency such as growth retardation and increased susceptibility to infection. It is, therefore, very important that not only the severe cases of hypovitaminosis A be diagnosed for immediate treatment, but also the marginal cases of vitamin A deficiency in vulnerable populations be diagnosed as early as possible so that appropriate preventive measures be implemented. Available methods for the diagnosis of vitamin A deficiency can be classified into four categories: clinical, biochemical, functional, and dietary. Clinical diagnosis is based on examining ocular and extraocular signs of hypovitaminosis A, and is only useful for the detection of severe cases. Biochemical methods are based on the plasma concentrations of retinol and retinol-binding protein (RBP), and liver reserve of vitamin A whenever possible. Two other commonly used diagnostic tests are: functional testing for nightblindness using dark adaptation time, and pathological testing for ocular signs of conjunctival xerosis, with or without the use of Rose Bengal or lissamine green dye. Dietary method for the diagnosis of vitamin A deficiency is based on the estimation of dietary intake of vitamin A and carotenoids. In addition, there are newer methods such as isotope dilution and relative dose response (RDR) techniques which have been recently proposed for the diagnosis of vitamin A deficiency. RDR appears to be a reliable and sensitive indicator of marginal vitamin A. However, the most desirable approach to diagnosis may be one based on multiple indicators for the accurate assessment of vitamin A status in the community. The purpose of this paper is to draw attention to the problems of diagnosis, to recent advances and to our Brazilian experience in this important area of vitamin A research with significant global implications.

Child, Preschool↗
PubMed1987

[Relation of the major connector of a removable partial denture (RPD) with mandibular mucosal tissue; clinical case].

When the performance of removable partial prosthesis is analyzed, it can be seen that failures outnumber the successes. These failures, however, should not be imputed to the prostheses themselves, but rather to the fact that proper biomechanical principles were not observed in the planning of these devices. Each component of a prosthesis should be carefully planned in order to obtain maximum stability with respect to the supporting tissues. One of these principles is concevued to the relieve that must be established between major connectors and mandibular mucosae. It is important to remember that mandibular mucosae is fine, moveable, very sensitive and weak, so that this mucosae be considered very susceptible to mechanical aggression. In this work the authors emphasize the necessity of relieve in the mandibular major connector in order not to pressure the investing tissues. Otherwise serious periodontal damage can occur.

Denture Design↗
PubMed1986

Evaluation of rose bengal staining test and rapid dark-adaptation test for the field assessment of vitamin A status of preschool children in Southern Brazil.

The objective of this study was to evaluate two of several methods presently available for assessing vitamin A status of marginally malnourished preschool children of socioeconomically deprived families in Southern Brazil. The rose bengal staining test and rapid dark-adaptation test were evaluated by comparing their results with conventional methods that require estimation of dietary intake of vitamin A equivalents and determination of plasma levels of retinol before and after an oral supplementation of 200 000 IU vitamin A. Results indicate that neither test evaluated is useful by itself. There was no significant correlation between the results of the rose bengal staining test and the plasma levels of retinol. Also, no significant correlation was observed between the rapid dark-adaptation time and the vitamin A status of the preschool children as determined by plasma-retinol levels before and after vitamin A supplementation.

Brazil↗