Navegando por Orientadores "SILVA, Luiz Carlos Santana da"

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Acesso aberto (Open Access)
Análise da atividade enzimática de quitotriosidase como um marcador para a malária vivax: abordagens bioquímicas e moleculares
(Universidade Federal do Pará, 2010) CRUZ, Cleber Monteiro; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382
Chitotriosidase was the first described chitinase and its physiologic role is not entirely clear, although many studies have been showed its participation as a component of human immune response. A 24pb duplication on exon 10 of chit1 gene results on RNAm frameshift, leading to a 87 nucleotides deletion. This alteration generates a protein with no catalytic activity at all. This condition is called chitotriosidase deficiency and presents a frequency close to 6% of homozygosis duplication in different ethnical groups. Malaria is an amazon endemic parasitosis caused by protozoaries of genus Plasmodium and causes symptoms as fever, headache and vomit, which leads to a characteristic immune response. The objective of this study was to evaluate the chitotriosidase enzyme behavior in patients suffering of malaria in Pará state and to determine the frequency of 24pb duplication on chitotriosidase gene in a representative sample. Chitotriosidase measurement was made in 100 healthy individual and in 47 malarial patients. The molecular analysis of the 24pb duplication was realized in 100 volunteers trough a protocol which included DNA extraction techniques, PCR and 2,5% agarose gel visualization to verify normal fragments (normal homozygote: 195pb) and the 24pb duplication (mutant homozygote: 219pb; heterozygote: 219pb e 195pb). This study described at first time on scientific literature the chitotriosidase plasmatic levels increasing in patients suffering of malaria vivax compared to healthy individual. No association was observed between parasitemia and plasmatic chitotriosidase levels in malarial patients. Molecular analysis showed a frequency of 72% normal homozygotes, 24% heterozygotes and 4% mutant homozygotes to 24pb duplication. Allelic frequencies were around 84% to wild allele and 16% to mutant allele. No correlation was found between genotype and biochemical phenotype (represented by chitotriosidase levels) on control group.
Acesso aberto (Open Access)
Avaliação de um teste bioquímico de triagem para a detecção de indivíduos heterozigotos para a fenilcetonúria
(Universidade Federal do Pará, 2011-10-07) ANDRADE, Roseani da Silva; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382
Phenylketonuria (PKU) is an inherited metabolic disease resulting from deficiency of the enzyme phenylalanine hydroxylase (PAH) that converts the amino acid phenylalanine into tyrosine. This study aimed to investigate the metabolism of amino acids phenylalanine (Phe) and tyrosine (Tyr) in heterozygotes for PKU, in fasting and after an overload of Phe (25 mg / kg) using different biochemical parameters (levels of Phe and Tyr and relations Phe / Tyr and Phe ² / Tyr), to identify the best variable to discriminate heterozygotes for PKU and normal subjects. The protocol used was the measurement of plasma Phe and Tyr in the case of fasting, 30, 45, 60 and 90 minutes after the overload of Phe at a dose of 25mg/kg. The sample consisted of 50 individuals, 23 binding heterozygotes (10 men and 13 women) and a control group of 27 healthy individuals (13 men and 14 women), according to the matching criteria: gender and age (18 to 44 years) . To analyze the effect of an overload of Phe in each group, the results of the parameters Phe, Tyr, Phe / Tyr and Phe2/Tyr after overload were compared with those observed in the fasting state. Statistical inferences were performed between groups in longitudinal and transverse aspects and applied the Student t test, Wilcoxon test, Student test and its equivalent nonparametric test and the Mann-Whitney test. Evaluating the ROC curve of the variables used, the three best parameters to classify heterozygous and normal subjects were: the dosage of Phe 45 and 90 minutes, as well as the result of micromolar Phe2/Tyr fraction after 90 minutes of overload. The discriminant function showed 86% accuracy and a correct classification of 94.4% of individuals heterozygous for PKU.
Acesso aberto (Open Access)
Cinética da enzima alfa-galactosidase a e investigação de doença de fabry em pacientes hemodialisados
(Universidade Federal do Pará, 2011-11-01) ARAGÃO, Camila de Britto Pará de; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382
Human alpha-galactosidase A (α-Gal A) is a lysosomal enzyme which is deficient in Fabry disease. Fabry disease is a sphingolipidosis which chronic kidney failure (CKF) is the most important cause of morbidity and mortality. The aim of this study was the establishment of a laboratorial protocol that allows the diagnosis of Fabry’s disease in plasma and leukocytes, the analysis of α-Gal A kinetic features in plasma and searching for potential Fabry patients in 25 individual with unknown CKF. Reproducibility and fluorescence stability of the enzymatic method were also evaluated. The assay standardization was realized with the fluorescent substrate 4- methylumbeliferil-α-D-galactopyranoside. Reproducibility was evaluated using plasma samples stored at a 4ºC, -20ºC and -70ºC, the assay was performed once a month until 6 months and fluorescence stability was evaluated until 24 hours after the end of the assay. The standardization allowed the establishment of value references to α-Gal A in Pará State, from 4 to 28 nmoles/h/mL (plasma) and 20 to 96 nmoles/h/mg protein (leukocytes). α-Gal A enzyme was thermolabile and 1 minute of preincubation at 60ºC was sufficient to decrease 71.09% of its entire activity. The activity of the α-Gal A enzyme increased progressively according to incubation time, between 15 and 180 minutes. Its activity was better at pH 4,8, the Km value for the α-Gal A enzyme was 1.007 mM, and maximum reaction velocity was 30.9 nmoles/h/mL. The best storage temperature for plasma samples was -20ºC that showed less variation until 6 months. The enzyme method is stable and even after 24 hours, at room temperature, the fluorescence remained the same. All CKF patients with unknown cause presented α-Gal A activity between normal values, therefore neither was diagnosed with Fabry disease. Understanding the kinetics of the α-Gal A enzyme and its in vitro behavior will contribute to improvements in the laboratory diagnosis of Fabry disease, and provide a diagnostic baseline for the analysis of individuals affected by mutations in this enzyme.
Acesso aberto (Open Access)
Dispositivo fisioterapêutico gerador de pressão positiva expiratória com propriedades fluxo-dependentes
(Universidade Federal do Pará, 2016-12-21) NINA, Janize Costa; NORMANDO, Valéria Marques Ferreira; http://lattes.cnpq.br/7098261432975265; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382
Positive expiratory pressure therapy is safe and effective for the prevention, reversal of atelectasis and removal of pulmonary secretions. The experimental study aimed to elaborate a physiotherapeutic device capable of generating positive expiratory pressure for patients in spontaneous breathing and evaluating their mechanical performance. The composition of the physiotherapeutic device consisted of 14 components, produced in aluminum and plastic, allowing to present characteristics of a flow-dependent non-gravitational resistor. The pressures obtained through the high flux flowmeter model Certifir® FA TSI (TSI Corporated, USA) had influence of the orifice strength with diameters of 1.5, 2.0, 3.0, 4.0 and 5.0mm, five-piston weights (1.5; 1.6, 2.0, 3.2 and 3.8g) and constant flows of 3, 5, 6, 9, 10 and 12L/min or piston firing flow. Among the five pistons, the piston 4 (3.2g) presented a better statistically significant result, reaching a pressure of 20cmH2O with flows of 8.16L/min, for the 1.5mm diameter bore. The proposed PEP device can generate therapeutic pressures between 10 and 20cmH2O, through a variation of low expiratory flows. It presents as singular characteristic the association of the diameter of the orifice with the weight of the piston to generate the positive pressure. Future studies are needed in order to promote the validation of the physiotherapeutic device in healthy children and subsequent analysis in patients with pulmonary conditions to obtain scientific data that represent our clinical practice.
Acesso aberto (Open Access)
Estudo de polimorfismos no gene GRIK2 em pacientes com doença de Parkinson
(Universidade Federal do Pará, 2017-01-18) BARBOSA, Suane Reis; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382
Parkinson's Disease (PD) is a complex neurodegenerative disorder resulting from the multiple combination of genetic and environmental factors. One of the factors that may contribute to PD development is the excitotoxicity, a pathophysiological process caused by intense stimulation of glutamatergic receptors. This neurotoxic phenomenon is associated with the excessive influx of ions in the cell (Na +, Cl- and especially Ca 2+), resulting in neuronal death. It was evidenced that the GluK2 subunit of the kainate type glutamate receptor interacts with parkin, accentuating the excitotoxic process. The GRIK2 gene encodes this subunit, expressed in regions of the brain involved in motor activity, and may undergo alternative splicing or RNA editing, introducing new isoforms that may alter the ion conductance at the receptor. There are no studies in the literature on the association of polymorphisms in the GRIK2 gene with PD. This study aimed to determine the genotypic and allelic frequencies, as well as to verify a possible influence of the SNPs rs3213607, rs2227281, rs2227283, rs2235076, rs4839797, rs2518261 from GRIK2 gene in a group of patients with PD. A case-control study was performed, with analysis of DNA samples from 129 individuals from the control group and 61 patients from the PD group. It was found that for the SNP rs2518261 (C/T), allele T appeared to have a risk effect in the DP group (x2= 19.085; p-value <0.0001; OR = 2.75; CI = 1.75-4 , 27). In this polymorphism it was also observed that TT genotype may represent a factor associated with the tremor presence in the PD group (p-value = 0.02). These pioneer results of this study, suggest that further research is needed to investigate the contribution of GRIK2 gene to PD.
Acesso aberto (Open Access)
Existe uma relação entre as frequências dos polimorfismos do gene TSHR e os marcadores de ancestralidade genética em pacientes com hipotireoidismo congênito primário?
(Universidade Federal do Pará, 2024-10) LOURENÇO, Victor Henrique Botelho; ALVES, Erik Artur Cortinhas; http://lattes.cnpq.br/9125390243566397; HTTPS://ORCID.ORG/0000-0001-8824-8075; SILVA, Luiz Carlos Santana da; http://lattes.cnpq.br/6161491684526382; https://orcid.org/0000-0003-1017-6221
Literature shows a correlation between ethnicities and pathogenic variants of the receptor TSH hormone gene (TSHR). Some of these polymorphisms can be as risk factors for the development of Primary Congenital Hypothyroidism (PCH). In this study, we investigate the relationship between the frequencies of TSHR gene polymorphisms with the genetic influence of African, Amerindian, and European ancestry informative markers in patients diagnosed with PCH in an Amazonian population in Brazil. The study was conducted on samples of 106 patients diagnosed with PCH. Genomic DNA was isolated from peripheral blood samples, and 10 exons from the TSHR were automatically sequenced. Ancestry-Informative Marker identification was performed using a panel of 48 markers, and the results were compared with parental Amerindian, Western European, and Sub-Saharan African populations using Structure v2.3.4 software. Four nucleotide alterations were identified among 49 patients. The distribution of tested ancestry markers among the 106 patients indicated a significant difference in the percentages of Amerindian (32.2%), European (41.80%), and African (25.9%) ancestry. A logistic regression analysis revealed no significant association between the rs2075179 and rs1991517 polymorphisms and genetic ancestry. This study found no evidence of a relationship between polymorphic TSHR gene variants and genetic ancestry markers in patients with PCH.