RESUMO
It is known that experimental tooth movement stimulates the gene expression of connective tissue growth factor (CTGF) and induces apoptosis in osteocytes in rats. We hypothesized that there is a relationship between CTGF expression and the induction of apoptosis in osteocytes, to play a significant role in triggering bone remodeling during experimental tooth movement. In this study, CTGF mRNA expression was detected at 2 hours in osteocytes on the pressure side, followed by apoptosis at 6 hours after tooth movement in mice. The number of empty lacunae significantly increased on day 1 after mechanical stimulation. Thereafter, the number of osteoclasts significantly increased on the pressure side of the alveolar bone on day 3. Tooth movement increased rapidly on day 10. These findings suggest that CTGF expression, followed by apoptosis in osteocytes in response to mechanical stimulation, might play a significant role in triggering bone remodeling during tooth movement.
Assuntos
Processo Alveolar/metabolismo , Remodelação Óssea/fisiologia , Fator de Crescimento do Tecido Conjuntivo/metabolismo , Osteócitos/metabolismo , Técnicas de Movimentação Dentária , Fosfatase Ácida/metabolismo , Processo Alveolar/citologia , Análise de Variância , Animais , Apoptose/fisiologia , Fator de Crescimento do Tecido Conjuntivo/genética , Marcação In Situ das Extremidades Cortadas , Isoenzimas/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos ICR , RNA Mensageiro/análise , Estatísticas não Paramétricas , Fosfatase Ácida Resistente a TartaratoRESUMO
To improve solute removal efficiency, several types of dialyzers with enhanced internal filtration were introduced for clinical application. In these dialyzers, enhanced internal filtration increased convective transport of the solute, in addition to diffusive transport. In this study, the effects of internal filtration on solute removal efficiency were examined by both analytic and experimental studies. Internal filtration is affected by blood (Q(B)) and dialysate (Q(D)) flow rates; the patient's hematocrit and plasma level of total protein; and the effective length (L(eff)), inner diameter (D), and density ratio (DR) of the hollow fibers. An analytic model was introduced for the estimation of the changes in mass and momentum along the dialyzer. It clarified the effects of these parameters on maximum internal filtration flow rate (Q(IF)) and clearance (K) of urea (60 daltons), vitamin B(12) (1,355), and myoglobin (17,000). As a result of the analytic study, Q(IF) was increased, resulting in a smaller D, a longer L(eff), and a larger DR value. Several types of dialyzers with the same cellulose triacetate membrane, produced by Toyobo Co, Ltd., Ohtsu, Japan, and Nissho Corporation, Kusatsu, Japan, were used for the experimental study. An in vitro evaluation using myoglobin solution showed the same trends as found in the analytic study. For example, a dialyzer with 150 microm of D has a 72.0 ml/min myoglobin K value, much higher than that of 53.7 ml/min for a dialyzer with 200 microm of D under constant Q(B) (300 ml/min) and DR (50%) values. Development of a dialyzer with enhanced internal filtration, however, should take the patient's safety into account, and hemolysis and endotoxin invasion from the dialysate to the patient should be avoided.
