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Biomedical subjects

A R Vieira

Publications and source records attributed to A R Vieira.

At least 19 recordsLinked to original sources
PubMed2006

The potential role of increased adrenal volume in the pathophysiology of obesity-related type 2 diabetes.

The hypothalamic-pituitary-adrenal (HPA) axis seems to play an important role in obesity and Type 2 diabetes (DM). The aim of the present study was to determine the adrenal volume in obese patients with DM in comparison to obese non-diabetic patients. Eleven diabetic obese and 19 non-diabetic obese women were sequentially invited to take part in the study. Computed tomography (CT) scan of the abdomen was performed to determine adrenal volume, visceral (VF) and sc fat (SCF). Daily urinary free cortisol (UFC) was used as a measure of integrated cortisol production. In the diabetic patients, hemoglobin A1c was measured as an index of metabolic control. Compared to nondiabetic controls, patients with diabetes had a significantly higher total adrenal volume (4.29+/-1.50 vs 2.95+/-1.64; p=0.03). A highly significant correlation was detected between VF and VF/SCF ratio and total adrenal volume in the whole group (r=0.36, p=0.04 and r=0.48, p=0.008, respectively). This study, therefore, suggests an association between abdominal obesity, enlarged adrenals and Type 2 diabetes. These findings support the hypothesis that an increased activity of the HPA axis in obese subjects may be involved in the pathogenesis of Type 2 diabetes.

Adrenal Glands↗
PubMed2006

Genetic evidence for the role of loci at 19q13 in cleft lip and palate.

BACKGROUND: Clefts of the lip and palate are common birth defects, affecting approximately 1 in 700 births worldwide. The aetiology of clefting is complex, with multiple genetic and environmental influences. METHODS: Genotype based linkage disequilibrium analysis was conducted using the family based association test (FBAT) and the likelihood ratio test (LRT). We also carried out direct sequencing of the PVR and PVRL2 candidate genes based on their homology to PVRL1, a gene shown previously to cause Margarita Island clefting. Participants included 434 patients with cleft lip with or without cleft palate or cleft palate only and their mothers from eight countries in South America, 205 nuclear triads (father-mother-affected child) from Iowa, 541 nuclear triads from Denmark, and 100 patients with cleft lip and palate from the Philippines. RESULTS: An allelic variant in the PVR gene showed statistically significant association with both South American and Iowa populations (p = 0.0007 and p = 0.0009, respectively). Direct sequencing of PVR and PVRL2 yielded 26 variants, including two rare amino acid changes, one in each gene, which were not seen in controls. CONCLUSIONS: We found an association between a common variant in a gene at 19q and isolated clefting in two heterogeneous populations. However, it is unclear from our data if rare variants in PVR and PVRL2 are sufficient to cause clefting in isolation.

Alleles↗
PubMed2004

MSX1, PAX9, and TGFA contribute to tooth agenesis in humans.

In this study, we sought to determine the association between tooth agenesis and DNA sequence variation in the genes MSX1 and PAX9 in an ethnically diverse human population. Since cleft lip/palate is also associated with both tooth agenesis and the gene TGFA, we included TGFA in the analysis as well. Cheek swab samples were obtained for DNA analysis from 116 case/parent trios. Probands had at least one developmentally missing tooth, excluding third molars. Genotyping was performed by single-strand conformational polymorphism or kinetic polymerase chain-reaction assays. Transmission distortion of the marker alleles and DNA sequence analysis was performed. Results showed that tooth agenesis is associated with markers of the genes MSX1 and TGFA. No mutations were found in MSX1 or PAX9 coding regions. There were statistically significant data suggesting that MSX1 interacts with PAX9. These findings suggest that MSX1, PAX9, and TGFA play a role in isolated dental agenesis.

Adolescent↗
PubMed2003

Inheritance of cleft palate in South America: evidence for a major locus recessive.

OBJECTIVES: Determine the model of inheritance of non-syndromic cleft palate in humans. DESIGN: Complex segregation analysis performed in families of consecutive newborns affected with non-syndromic cleft palate. SETTING AND SAMPLE POPULATION: The Latin American Collaborative Study of Congenital Malformations (ECLAMC). Four hundred and seven consecutive newborns affected with non-syndromic cleft palate registered during the period 1967-97. OUTCOME MEASURE: Likelihood ratio test and Akaike information criterion (AIC) values. RESULTS: The single major locus recessive model provided a significantly better explanation of the data. It was the most parsimonious and had the smallest AIC value of the six models tested with approximately the same likelihood as the general model (chi2 = 2.44, p = 0.5). CONCLUSIONS: To have defined a genetic model for non-syndromic cleft palate and provided evidence for a single major locus inheritance suggests that genetic linkage studies could be implemented.

Cleft Palate↗
PubMed2003

Complete sequencing shows a role for MSX1 in non-syndromic cleft lip and palate.

MSX1 has been proposed as a gene in which mutations may contribute to non-syndromic forms of cleft lip and/or cleft palate. Support for this comes from human linkage and linkage disequilibrium studies, chromosomal deletions resulting in haploinsufficiency, a large family with a stop codon mutation that includes clefting as a phenotype, and the Msx1 phenotype in a knockout mouse. This report describes a population based scan for mutations encompassing the sense and antisense transcribed sequence of MSX1 (two exons, one intron). We compare the completed genomic sequence of MSX1 to the mouse Msx1 sequence to identify non-coding homology regions, and sequence highly conserved elements. The samples studied were drawn from a panethnic collection including people of European, Asian, and native South American ancestry. The gene was sequenced in 917 people and potentially aetiological mutations were identified in 16. These included missense mutations in conserved amino acids and point mutations in conserved regions not identified in any of 500 controls sequenced. Five different missense mutations in seven unrelated subjects with clefting are described. Evolutionary sequence comparisons of all known Msx1 orthologues placed the amino acid substitutions in context. Four rare mutations were found in non-coding regions that are highly conserved and disrupt probable regulatory regions. In addition, a panel of 18 population specific polymorphic variants were identified that will be useful in future haplotype analyses of MSX1. MSX1 mutations are found in 2% of cases of clefting and should be considered for genetic counselling implications, particularly in those families in which autosomal dominant inheritance patterns or dental anomalies appear to be cosegregating with the clefting phenotype.

Amino Acid Sequence↗
PubMed2003

Oral clefts and syndromic forms of tooth agenesis as models for genetics of isolated tooth agenesis.

Genetic defects responsible for tooth agenesis are only now beginning to be uncovered. MSX1 and PAX9 have been associated with tooth agenesis in mice and humans, but interestingly for humans, these genes are associated with specific missing teeth. Mouse models also show that specific genes contribute to the development of specific types of teeth. A precise description of the phenotype specifying which teeth are missing has become fundamental. Mendelian segregation can be identified in families with tooth agenesis, but heterogenous or multiple genes may be responsible for the development of specific types of teeth agenesis in humans. Data from animal models are still very complex, and the human embryology is still poorly understood. Oral clefts and syndromic forms of tooth agenesis may be the best models for isolated tooth agenesis. In the future, a precise description of the missing teeth in syndromes involving tooth agenesis may be useful.

Animals↗
PubMed2003

MSX1 and TGFB3 contribute to clefting in South America.

MSX1 and TGFB3 have been proposed as genes in which mutations may contribute to non-syndromic forms of oral clefts; however, an interaction between these genes has not been described. The present study attempts to detect transmission distortion of MSX1 and TGFB3 in 217 South American children from their respective mothers. With transmission disequilibrium test analysis, cleft lip with/without cleft palate, cleft lip with palate plus cleft palate only, and all datasets combined showed evidence of association with MSX1 (p = 0.004, p = 0.037, and p = 0.001, respectively). With likelihood ratio test analysis, "cleft lip only" showed association with MSX1 (p = 0.04) and "cleft palate only" with TGFB3 (p = 0.02). A joint analysis of MSX1 and TGFB3 suggested that there may be an interaction between these two loci to increase cleft susceptibility. These results suggest that MSX1 and TGFB3 mutations make a contribution to clefts in South American populations.

Alleles↗
PubMed2002

Genetic origins in a South American clefting population.

It has been proposed that susceptibility to clefting in South America is related to Amerindian ancestry, where clefting is present at a higher frequency than in the other admixed populations (Caucasian and African) that make up the diverse racial mix of current South Americans. To clarify the genetic origins and establish a method for genetic mapping, mitochondrial DNA variation and Y-chromosome markers were studied in a South American population affected with clefting. Two-hundred and seventeen subjects and matched controls were selected through the Latin-American Collaborative Study of Congenital Malformations (ECLAMC). The case group showed a higher frequency of Native American haplogroups and a lower frequency of African haplogroups (p < 0.00001). In addition, the case group showed a much higher frequency of the specific native American haplogroup D than the control group (p < 0.00001). For the Y-chromosome markers, the case group showed a lower frequency of the African-specific marker, YAP (p = 0.002), and a higher frequency of the Native American-specific marker, DYS199 (p < 0.00001). Even though differences were found in the frequencies of the markers studied, the contribution of each founder population was similar for both groups. Results suggest a strong Native American maternal contribution and a strong Caucasian (Spanish and Portuguese) paternal contribution to the population studied. The implications of this finding include the possibility of using admixture mapping approaches to this population.

Chromosomes, Human, Y↗
PubMed2000

Formation of alkali-soluble fluoride on the surface of human dental enamel after treatment with fluoridated gels: influence of the pH variation and of the treatment time.

The aim of this study was to quantify, in vitro, the formation of CaF2 after the application of three fluoridated gels: one neutral, one acidulated and another highly acidulated, on a bovine enamel dental surface treated with a Dijkman's demineralizing solution (1990). 145 sections were utilized, obtained from 145 sound teeth and divided into seven groups: C (enamel without treatment); FN1 (enamel demineralized and treated with neutral gel for 1 minute); FN4 (enamel demineralized and treated with neutral gel for 4 minutes); FFA1 (enamel demineralized and treated with acidulated gel for 1 minute); FFA4 (enamel demineralized and treated with acidulated gel for 4 minutes); FAA1 (enamel demineralized and treated with highly acidulated gel for 1 minute) and FAA4 (enamel demineralized and treated with highly acidulated gel for 4 minutes). The formation of CaF2 was analyzed by SEM and chemically by Caslavska's method (1975). The average and standard deviations from the groups studied were respectively: C-0.63; 0.38; FN1-23.06; 16.52; FFA1-54.11; 49.00; FAA1-43.87; 32.66; FN4-34.92; 23.00; FFA4-67.91; 42.36; FAA4-56.03; 38.96. (Mann-Whitney non-parametric test). The time of application did not interfere in the CaF2 formation from the acidulated and highly-acidulated gels. A minor concentration of fluoride and amount of pH from highly-acidulated gel did not affect the higher formation from the CaF2 in relation to the acidulated gel in both cases when the application was evaluated.

Acidulated Phosphate Fluoride↗
PubMed2000

Pacifier-sucking associated with a bizarre habit: a case report.

A case of a child, who used the pacifier with an uncommon habit is presented. She pulled out the hair on the right side of her head after rolling it round the base of the pacifier. She then sucked it and swallowed it. Based on this report the authors are emphasizing the importance of accompanying the orofacial development of the child as from its first year of life.

Bezoars↗
PubMed1999

Fluoride uptake and release by composites and glass ionomers in a high caries challenge situation.

PURPOSE: To evaluate the behavior of composite resins and glass ionomer cements with regard to the uptake and release of fluoride, in a high caries challenge situation. MATERIALS AND METHODS: Standard test specimens of glass ionomer cement (Chelon Fil), a resin-modified glass ionomer (Vitremer), two polyacid-modified composite resins (VariGlass and Dyract) and a composite resin (Heliomolar), were submitted for 14 days to demineralization and remineralization cycles in order to simulate a high caries challenge, while from the eighth day onward, a fluoridated dentifrice solution was applied for 5 minutes twice a day and the daily fluoride release of those materials to the mediums was quantified and compared. Fifteen test specimens were prepared for each material, making up a total of 75. RESULTS: All materials studied, except for Heliomolar from day 4 to day 7 in the demineralizing solution, were capable of releasing fluoride in measurable quantities during the whole experiment. The fluoride amounts released by Chelon Fil, Vitremer, VariGlass and Dyract were significantly higher in the demineralizing solution (ANOVA, P < 0.05) than in the remineralizing solution, during almost the entire experiment. The fluoride amounts released by Heliomolar were significantly higher in the remineralizing solution (ANOVA, P < 0.05) than in the demineralizing solution, during almost the entire experiment. All materials studied were capable of uptaking fluoride from the dentifrice solution and of later releasing it to the solution, maintaining the release relatively constant and at a higher level than that seen between days 5 and 7.

Acrylic Resins↗
PubMed1999

[Analysis of dental students' knowledge and concepts in oral health: evaluation by concept maps].

This study sought to analyze senior dental students' cognitive structure concerning the topic of "enamel", which is fundamentally important for understanding oral health, since it offers basic scientific concepts for clinical and preventive practices and is the main subject of several courses during dentistry training. The strategy used to analyze students' cognitive structures was Novak's Concept Maps, based on Ausubel's Meaningful Learning theory. Analysis of students' maps allowed for a study of students' cognitive structure and concepts concerning oral health. It also fostered a diagnosis of students' knowledge in several important aspects of scientific and professional training. The results highlighted the need for rethinking the teaching/learning process in dentistry training.

Concept Formation↗
PubMed1997

VariGlass fluoride release and uptake by an adjacent tooth.

PURPOSE: To quantitatively analyze in vitro the fluoride release from proximal VariGlass restorations and resulting uptake by the enamel of adjacent teeth. MATERIALS AND METHODS: Sixty impacted third molars were used and assigned to three groups: C: control, teeth without restorations; RC: teeth with resin composite restorations (Prisma APH); and PMRC: teeth with polyacid-modified resin composite restorations (VariGlass). Each group consisted of four sets of five teeth each. In the latter two sets, by alternating restored and unrestored teeth, the proximal surfaces of three unrestored teeth with an area of exposed enamel were in contact with the restored proximal surfaces of two other teeth. The sets were submitted to high caries challenge conditions with demineralizing and remineralizing solutions for 14 days. The fluoride of each solution and the fluoride uptake were determined and statistical analyses were carried out (ANOVA and Tukey's test). RESULTS: The highest mean fluoride concentration occurred with Group PMRC in both kinds of solutions (P < 0.01), but this value was higher in the demineralizing solution (P < 0.01). Over the 14 days, however, this mean gradually decreased in both solutions (P < 0.01). Group PMRC also showed the highest mean fluoride uptake (P < 0.01), which gradually decreased with depth in the enamel (P < 0.01).

Acrylic Resins↗
PubMedDate not supplied

[Hemoptysis and the adult respiratory distress syndrome as the causes of death in leptospirosis. Changes in the clinical and anatomicopathological patterns].

Human leptospirosis, one of the main urban endemics/epidemics in Brazil, has dramatically grown in the last three decades, especially after floods caused by summer rains. This presentation describes recent changes in the clinical patterns of this pathology in our region, expressed by the emergence of massive haemoptysis and acute respiratory distress syndrome, or both conditions associated. The evident changes in the respiratory structures emerged as a serious life threat and death mechanisms, becoming the main cause of death in leptospirosis among us because of their high incidence. This new face of the disease demands a revision of current concepts about its seriousness and raises speculations about the pathogenesis of such alterations.

Adult↗
PubMedDate not supplied

Disseminated American muco-cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis in a patient with AIDS: a case report.

The authors report a case of culture-proven disseminated American muco-cutaneous leishmaniasis caused by Leishmania braziliensis braziliensis in an HIV positive patient. Lesions began in the oropharynx and nasal mucosa eventually spreading to much of the skin surface. The response to a short course of glucantime therapy was good.

Acquired Immunodeficiency Syndrome↗