RESUMO
This cross-sectional study aimed to investigate the association between developmental defects of enamel (DDE) and single nucleotide polymorphisms (SNPs) in the genes encoding the vitamin D receptor (VDR) and parathyroid hormone (PTH). Orthodontic patients receiving treatment at a dental school were selected through convenience sampling. Intra-oral photographs were used to assess DDE, which were classified according to the criteria proposed by Ghanim et al. (2015) by a single calibrated examiner (Kappa>0.80). Enamel hypoplasia, molar-incisor hypomineralization (MIH), hypomimineralized second primary molar (HSPM), and non-MIH/HSPM demarcated opacities were considered for the analysis. Genomic DNA was extracted from buccal cells. The SNPs in VDR (rs7975232) and PHT (rs694, rs6256, and rs307247) were genotyped using real-time polymerase chain reactions (PCR). Statistical analyses were performed using the PLINK software (version 1.03, designed by Shaun Purcell, EUA). Chi-square or Fisher's exact tests were performed at a significance level of 5%. Ninety-one (n=91) patients (49 females and 42 males) (mean age of 14.1±5.8 years) were included. The frequency of DDE was 38.5% (35 patients). Genotype distributions were in Hardy-Weinberg equilibrium. No significant statistical association was found between DDE and the SNPs evaluated. A borderline association (p=0.09) was observed between DDE and the CC haplotype for SNP rs7975232 in VDR. In conclusion, the selected SNPs in VDR and PTH genes were not associated with DDE in the studied samples.
Assuntos
Hipoplasia do Esmalte Dentário , Hormônio Paratireóideo , Polimorfismo de Nucleotídeo Único , Receptores de Calcitriol , Humanos , Receptores de Calcitriol/genética , Feminino , Estudos Transversais , Masculino , Hormônio Paratireóideo/genética , Hipoplasia do Esmalte Dentário/genética , Criança , Adolescente , Esmalte Dentário/anormalidades , Reação em Cadeia da Polimerase em Tempo Real , GenótipoRESUMO
BACKGROUND: Calcium gradient, the difference between serum calcium and dialysate calcium d[Ca], is the main contributor factor influencing calcium transfer during hemodialysis. The impact, however, of bone turnover, on calcium mass transfer during hemodialysis is still uncertain. METHODS: This prospective cross-sectional study included 10 patients on hemodialysis for a 57.6±16.8 months, with severe hyperparathyroidism. Patients were submitted to 3 hemodialysis sessions using d[Ca] of 1.25, 1.5 and 1.75 mmol/l in three situations: pre-parathyroidectomy (pre-PTX), during hungry bone (early post-PTX), and after stabilization of clinical status (late post-PTX). Biochemical analysis and calcium mass transfer were evaluated and serum bone-related proteins were quantified. RESULTS: Calcium mass transfer varied widely among patients in each study phase with a median of -89.5, -76.8 and -3 mmol using d[Ca] 1.25 mmol/L, -106, -26.8 and 29.7 mmol using d[Ca] 1.50 mmol/L, and 12.8, -14.5 and 38 mmol using d[Ca] 1.75 mmol/L during pre-PTX, early post-PTX and late post-PTX, respectively, which was significantly different among d[Ca] (p = 0.0001) and among phases (p = 0.040). Ca gradient and delta of Ca also differed among d[Ca] and phases (p<0.05 for all comparisons), whether ultrafiltration was similar. Serum Osteocalcin decreased significantly in late post-PTX, whereas Sclerostin increased earlier, in early post-PTX. CONCLUSIONS: The skeleton plays a key role in Ca mass transfer during dialysis, either by determining pre-dialysis serum Ca or by controlling the exchangeable Ca pool. Knowing that could help us to decide which d[Ca] should be chosen in a given patient.
Assuntos
Osso e Ossos/metabolismo , Cálcio/metabolismo , Hiperparatireoidismo Secundário/sangue , Paratireoidectomia , Diálise Renal/métodos , Insuficiência Renal Crônica/sangue , Proteínas Adaptadoras de Transdução de Sinal , Adulto , Proteínas Morfogenéticas Ósseas/sangue , Proteínas Morfogenéticas Ósseas/genética , Osso e Ossos/patologia , Sinalização do Cálcio , Estudos Transversais , Feminino , Regulação da Expressão Gênica , Marcadores Genéticos/genética , Humanos , Hiperparatireoidismo Secundário/genética , Hiperparatireoidismo Secundário/patologia , Hiperparatireoidismo Secundário/cirurgia , Transporte de Íons , Masculino , Pessoa de Meia-Idade , Osteocalcina/sangue , Osteocalcina/genética , Hormônio Paratireóideo/sangue , Hormônio Paratireóideo/genética , Estudos Prospectivos , Insuficiência Renal Crônica/genética , Insuficiência Renal Crônica/patologia , Insuficiência Renal Crônica/terapiaRESUMO
A stability-indicating capillary zone electrophoresis (CZE) method was validated to assess the content/potency of the recombinant human parathyroid hormone (rhPTH 1-34), using ranitidine as internal standard (IS). A fused-silica capillary, (i.d. of 50µm; effective length of 40cm) was used at 25°C; the applied voltage was 20kV. The background electrolyte solution consisted of 50mmolL-1 sodium dihydrogen phosphate solution at pH 3.0. Injections were performed using a pressure mode at 50 mbar for 45s, with detection by photodiode array (PDA) detector set at 200nm. Separation was obtained with a migration time of 5.3min, and was linear over the concentration range of 0.25-250µgmL-1 (r2 =0.9992). Specificity and stability-indicating capability were established in degradation studies, which also showed that there was no interference of the excipients. The accuracy was 100.28% with bias lower than 0.85%. Analyses of the same batches showed mean differences of the estimated content/potencies of 0.61%, 1.31% higher and 0.86% lower as compared to the validated reversed-phase and size exclusion liquid chromatography methods, and to the UMR-106 cell culture bioassay, respectively, with non-significant differences (p>0.05). Degraded forms were also subjected to the in vitro cytotoxicity test. The results obtained showed the capabilities of each one of the methods, and constitute an alternative strategy to monitor stability, improve the quality control and ensure the batch-to-batch consistency of bulk and finished biotechnology-derived medicine.
Assuntos
Cromatografia em Gel/métodos , Cromatografia de Fase Reversa/métodos , Eletroforese Capilar/métodos , Hormônio Paratireóideo/metabolismo , Proteínas Recombinantes/metabolismo , Animais , Bioensaio/métodos , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Humanos , Células L , Camundongos , Hormônio Paratireóideo/genética , Hormônio Paratireóideo/farmacologia , Ranitidina/metabolismo , Ranitidina/normas , Ratos , Proteínas Recombinantes/farmacologia , Padrões de Referência , Reprodutibilidade dos TestesRESUMO
Las glándulas paratiroides fueron descubiertas a finales del siglo XIX y su función a principios del siglo XX era controvertido. El rol fue definido posterior a experimentos realizados por Collip (1925) donde sometía el tejido paratiroideo a ácido clorhídrico a altas temperaturas obteniendo extractos capaces de disminuir la tetania en perros posterior a una paratiroidectomía total, dicho extracto sería denominado hormona paratiroidea 35 años después. Aurbach (1959) empleó solventes orgánicos para liberar el componente activo sin fragmentarlo, en combinación con técnicas de filtración por gel investigadores como Brewer (1970) lograron identificar las porciones indispensables para la función biológica. Además, el desarrollo de la biología molecular, inmunohistoquímica y tecnología de ADN recombinante, permitió deducir la secuencia de polipéptidos a partir de la copia reversa del ARNm y posteriormente sintetizar el polipéptido. En 1991, fue clonado el receptor de hormona paratiroidea. Se identifica una proteína relacionada a la hormona paratiroidea (PTHrP) cuya actividad biológica en la homeostasis del calcio y fosfato es indistinguible de la hormona paratiroidea, capaz de regular el crecimiento celular y la apoptosis por vía intracrina. Todo ello definido a partir experimentos de ablación genética y promovida por la búsqueda de la causa de la hipercalcemia maligna y el estudio de la enfermedad renal crónica
The parathyroid glands were discovered at the end of the 19th century and its role at the beginning of the 20th was controversial. Their role was defined later due experiments conducted by Collip (1925) where extracts of parathyroid tissue under high temperature hydrocloric acid decrease tetany in dogs with total parathyroidectomy. This substance 35 years later would be called parathyroid hormone. Aurbach (1959) used organic solvents to isolate the active unfragmented molecule. This combined with gel filtration techniques, allowed to researches like Brewer (1970) identify essential portions for biological activity. In addition, the development of molecular biology, inmnohistochemistry and DNA recombinant technology, made possible identify the polypeptide sequence by reverse mRNA and synthesize parathyroid hormone polypeptide. In 1991, parathyroid hormone receptor was cloned. Protein related to parathyroid hormone (PTHrP) was identified due to biological activity on calcium and phosphate homeostasis indistinguishable from the parathyroid hormone. Through experiments of genetic ablation, the PTHrP was identified as cell growth and apoptosis regulator by an intracrine pathway. All these achievements were promoted by the research to find the cause of malignant hypercalcemia and study chronic kidney disease