No association between dopamine D2 receptor (DRD2) alleles and crack/cocaine dependence in Brazilians

INTRODUCTION: The causal mechanisms behind crack/cocaine use are still unknown, but genetic influences are suggested. OBJECTIVE: To investigate the relationship between the genetic polymorphism TaqI (rs1800497) in the dopamine D2 receptor (DRD2) gene and susceptibility to crack/cocaine dependence in a group of addicts to crack/cocaine and a non-addicted group. METHODS: The case group (n=515) was composed of crack/cocaine-dependent men and the control group (n=106) comprised men who were considered not dependent on crack/cocaine. The oral hygiene habits, decayed, missing, and filled teeth index, gingival index, and plaque index were evaluated. The reference single nucleotide polymorphism (rs1800497 C/T) of the DRD2 gene was genotyped by a real-time polymerase chain reaction technique. Student's t-tests for independent samples or the non-parametric Mann-Whitney test were used to compare groups regarding quantitative variables. RESULTS: The case group showed a mean time of 9.91±7.03 years of crack use, and 61.06±92.96 stones/week. The socio-demographic profile of the sample was White, single men, with basic education, blue-collar worker, smoker, and reporting alcohol use. There was a high frequency of gingival inflammation, plaque accumulation, and caries experience. For all genetic models tested, there was no significant difference in the genotypic frequency in rs1800497 of the DRD2 gene, between case and control groups (p>0.05). CONCLUSION: The genetic variant in the DRD2 did not increase the vulnerability to develop crack/cocaine dependence. The complex genetic nature of crack/cocaine dependence and a large variation of DRD2 allele frequencies, depending on the population group sampled, could be one explanation for the no association.

Lack of association between delayed tooth emergence and single nucleotide polymorphisms in estrogen receptors

Abstract The purpose of the study was to investigate the association between single nucleotide polymorphisms (SNPs) in genes encoding estrogen receptors (ESR1 and ESR2, respectively) and delayed tooth emergence (DTE). This cross-sectional study was composed of biological unrelated children of both sexes, age ranging from 11 to 13 years old. DTE was defined when the successor primary tooth was still present in the oral cavity after its exfoliation time or the absence of the permanent tooth emergence into the oral cavity. Children were diagnosed with DTE when they had at least one delayed permanent tooth, according to age of exfoliation of each tooth proposed by The American Dental Association. Genomic DNA from saliva was used to evaluate the SNPs in ESR1 (rs9340799 and rs2234693) and ESR2 (rs1256049 and rs4986938) using Real-Time PCR. Chi-square or Fisher exact tests and Logistic Regression adjusted by age and gender were performed. SNP-SNP interaction was accessed by multifactor dimensionality reduction (MDR) analysis also adjusted by gender and age. The established alpha of this study was 5%. Among 537 included children, 296 (55%) were in the "DTE" group and the 241 (45%) were in the "Control" group. Age and gender were not statistically different among the groups (p>0.05). Genotype distribution of the SNPs rs9340799, rs2234693, rs1256049 and rs4986938 were not associated with DTE (p> 0.05). The models elected by MDR were not statistically significant either. Conclusions: The studied SNPs in ESR1 and ESR2 were not associated with permanent DTE.

RESUMO O objetivo do presente estudo foi investigar a associação entre polimorfismos de nucleotídeo único (SNPs) em genes que codificam receptores de estrógeno (ESR1 e ESR2, respectivamente) e o retardo na emergência dentária (DTE). Este estudo transversal foi composto por crianças biológicas não relacionadas de ambos os sexos, com idades entre 11 e 13 anos. O DTE foi definido pela presença do dente decíduo na cavidade bucal após seu tempo e também, quando as crianças apresentaram pelo menos um dente permanente com atraso. O DNA genômico foi usado para avaliar os SNPs em ESR1 (rs9340799 e rs2234693) e ESR2 (rs1256049 e rs4986938) usando PCR em tempo real. Foram realizados testes Qui-quadrado ou exato de Fisher e Regressão Logística ajustados por idade e sexo. A interação SNP-SNP foi acessada pela análise de redução de dimensionalidade multifatorial (MDR), também ajustada por sexo e idade. O alfa de 5% foi estabelecido. Entre 537 crianças incluídas, 296 (55%) estavam no grupo "DTE" e 241 (45%) estavam no grupo "Controle". A idade e o sexo não foram estatisticamente diferentes entre os grupos (p> 0,05). A distribuição de genótipos dos SNPs rs9340799, rs2234693, rs1256049 e rs4986938 não foi associada ao DTE (p> 0,05). Os modelos eleitos pelo MDR também não foram estatisticamente significativos. Conclusões: Os SNPs estudados na ESR1 e ESR2 não foram associados ao DTE na dentição permanente.

Calcium and phosphorus levels in saliva are influenced by genetic polymorphisms in estrogen receptor alpha and microrna17

Abstract Homeostasis between salivary calcium and phosphorus is important for maintaining oral health. The aim of this study was to evaluate if polymorphisms in ESR1 (Estrogen Receptor Alpha), ESR2 (Estrogen Receptor Beta) and miRNA17 (microRNA17) are associated with calcium and phosphorus levels in saliva. Saliva from 276 12-year-old children were collected by masticatory stimulation and calcium and phosphorus levels were determined by Mass Spectrometry. Genomic DNA was extracted from remaining saliva and genetic polymorphisms in ESR1 (rs12154178, rs1884051, rs9340799 and rs2234693), in ESR2 (rs4986938 and rs1256049) and in miRNA17 (rs4284505) were genotyped using TaqMan chemistry and a real-time PCR equipment. Statistical differences in genotype and allele distributions between 'low' and 'high' calcium and phosphorus levels were determined using chi-square or Fisher´s exact tests. The analysis was also adjusted by sex (alpha of 5%). ESR1 rs9340799 had the less common genotype associated with higher calcium levels (p=0.03). The less common allele of ESR1 rs1884051 was associated with lower phosphorus levels (p=0.005) and there was an excess of heterozygotes for miRNA17 rs4284505 among individuals with lower calcium levels (p=0.002), both adjusted by sex. This study provides evidence that genetic polymorphisms in ESR1 and miRNA17 are involved in determining salivary calcium and phosphorus levels.

Resumo A homeostasia entre cálcio e fósforo salivares é importante para a manutenção da saúde bucal. O objetivo deste estudo foi avaliar se polimorfismos genéticos no receptor de estrógeno alfa (ESR1), receptor de estrógeno beta (ESR2) e no microRNA17 (microRNA17) estão associados com os níveis salivares de cálcio e fósforo. Saliva de 276 crianças com 12 anos de idade foi coletada com estímulo mastigatório e os níveis de cálcio e fósforo foram determinados por Espectrofotometria de Massa. O DNA genômico foi extraído da saliva remanescente e os polimorfismos genéticos em ESR1 (rs12154178, rs1884051, rs9340799 e rs2234693), em ESR2 (rs4986938 e rs1256049) e no miRNA17 (rs4284505) foram genotipados pela reação em cadeia da polimerase em tempo real utilizando sondas TaqMan. As diferenças estatísticas nas distribuições alélicas e genotípicas entre "baixo" e "alto" níveis de cálcio e fósforo foram determinadas usando os testes qui-quadrado e teste exato de Fisher. As análises foram ajustadas por sexo (alfa de 5%). O polimorfismo rs9340799 em ESR1 foi o genótipo menos comum associado com altos níveis de cálcio (p=0,03). O alelo menos comum em ESR1 rs1884051 foi associado com baixos níveis de fósforo (p=0,005) e houve um excesso de heterozigotos para miRNA17 rs4284505 entre os indivíduos com baixos níveis de cálcio salivar (p=0,002), ambos ajustados pelo sexo. Este estudo fornece evidências de que polimorfismos genéticos em ESR1 e miRNA17 estão envolvidos na determinação dos níveis de cálcio e fósforo salivares.

Analysis of the association between lactotransferrin (LTF) gene polymorphism and dental caries

OBJECTIVE: The present study evaluated the association between lactotransferrin (LTF) gene polymorphism (exon 2, A/G, Lys/Arg) and dental caries. MATERIAL AND METHODS: A convenience sample of 110 individuals, 12 years old, was divided into: group 1, 48 individuals without caries experience (DMFT=0), and group 2, 62 subjects with caries experience (DMFT>1). DNA was obtained from a mouthwash with 3 percent glucose solution, followed by a scrapping of the oral mucosa. After DNA purification, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) was performed to access the study polymorphism. The LTF A/G (Lys/Arg) polymorphism had been previously reported as located in exon 1. RESULTS: Allele 1 of the study polymorphism was associated with low DMFT index and showed a protective effect against caries experience (OR=0.16, IC=0.03-0.76, p=0.01). CONCLUSIONS: Lactotransferrin A/G (exon 2, Lys/Arg) polymorphism was associated with susceptibility to dental caries in 12-year-old students.

Electromyographic evaluation of the upper lip according to the breathing mode: a longitudinal study

The present study aimed at analyzing and comparing longitudinally the EMG (electromyographic activity) of the superior orbicularis oris muscle according to the breathing mode. The sample, 38 adolescents with Angle Class II Division 1 malocclusion with predominantly nose (PNB) or mouth (PMB) breathing, was evaluated at two different periods, with a two-year interval between them. For that purpose, a 16channel electromyography machine was employed, which was properly calibrated in a PC equipped with an analogue-digital converter, with utilization of surface, passive and bipolar electrodes. The RMS data (root mean square) were collected at rest and in 12 movements and normalized according to time and amplitude, by the peak value of EMG, in order to allow comparisons between subjects and between periods. Comparison of the muscle function of PNB and PMB subjects at period 1 (P1), period 2 (P2) and the variation between periods (Ã) did not reveal statistically significant differences between groups (p < 0.05). However, longitudinal evaluation of the muscle function in PNB and PMB subjects demonstrated different evolutions in the percentage of required EMG for accomplishment of the movements investigated. It was possible to conclude that there are differences in the percentage of electric activity of the upper lip with the growth of the subjects according to the breathing mode.

Diagnóstico molecular da doença periodontal / Molecular diagnosis of periodontal disease

O cigarro, o estresse psicossocial e certos polimorfismos gênicos säo exemplos de fatores que aumentam o risco à periodontite, tornando os indivíduos mais suscetíves à progressäo ou agravamento da doença. Polimorfismos em genes de mediadores pró-inflamatórios, que caracterizam a resposta do hospedeiro, têm sido alvo de estudos recentes, que objetivam diagnosticar precocemente mecanismos destrutivos da doença. A realizaçäo de um simples bochecho com soluçäo açucarada pelo paciente pode permitir a análise de seu perfil de suscetibilidade genética à doença periodontal, o que pode ser de grande valia na prevençäo da instalaçäo e progressäo da doença periodontal em pacientes de risco

Análise bioquímica das metaloproteases da matriz extracelular durante atrofia experimental das glândulas salivares submandibulares em ratos / Analysis of the matrix metalloproteases in duct-ligated submandibular salivary glands of rats

O presente estudo teve por objetivo analisar a expressäo das metaloproteases da matriz extracelular durante a atrofia experimental das glândulas submandibulares em ratos, causada pela obstruçäo do ducto excretor principal. Os zimogramas realizados com extratos das porçöes internas e externas das glândulas salivares normais e ligadas mostraram que as principais enzimas gelatinolíticas possuíam pesos moleculares variando entre 72 kDa e 65 kDa. A atividade dessas enzimas aumentou progressivamente até o período entre 5 e 10 dias após a ligaçäo, decrescendo nos períodos subseqüentes. Foram também detectadas bandas migrando entre 92 kDa e 72 kDa, sendo essas enzimas detectadas em quantidades significativas apenas na regiäo da cápsula da glândula, no período de 2 dias. A confirmaçäo de que as metaloproteases da matriz têm um papel importante na remodelaçäo da matriz extracelular durante a atrofia experimental da glândula submandibular