RESUMEN
Substituent effects on the enantioselectivity for the lipase-catalyzed esterifications in organic solvents were studied by use of 2-(4-substituted phenoxy)propionic acids as the substrates with various substituents of H, F, Cl, CF(3), CH(3), CH(3)CH(2), and CH(3)O. The distinction in the behavior of their enantioselectivity was primarily responsible for the size effects of the substituents, although the substituents are far away from the stereocenter of the substrates. For the similar substituents in size, CH(3) and CF(3), however, their electronic effects played an important role in controlling the enantioselectivity. This variation of the enantioselectivity due to the electronic effects is also supported by the discussion based on the value of the Michaelis constant (K(m)) obtained. In addition, by raising the reaction temperature with enough water added to isopropyl ether as the reaction medium, the enantioselectivity is found to be dramatically enhanced for the substrate bearing CH(3)O group due to the strong electron-donating effect.
Asunto(s)
Lipasa/química , Fenilpropionatos/síntesis química , Candida/enzimología , Catálisis , Ésteres/síntesis química , Cinética , Solventes , Estereoisomerismo , TemperaturaRESUMEN
Survey of dental health condition was performed at a special nursing home for the elderly with senile dementia (28 subjects, 83.3 +/- 6.8 year-old; SD group) or without senile dementia (68 subjects, 84.6 +/- 7.2 year-old; NSD group). There was no difference in number of teeth survived between SD and NSD groups. However, the elderly in SD group had more unfunctionable and/or unrestorable teeth (C4) and less sound and filled teeth (SFT) than those in NSD group. Number of teeth of the elderly in 85- to 89-year-old group was smaller than those of not only younger but older age groups, irrespective of senile dementia. Lower canines showed the highest survival rate among all kinds of teeth in SD as well as in NSD group.
Asunto(s)
Demencia/complicaciones , Cuidado Dental para Ancianos , Atención Dental para la Persona con Discapacidad , Caries Dental/epidemiología , Arcada Parcialmente Edéntula/epidemiología , Anciano , Anciano de 80 o más Años , Enfermedad de Alzheimer/complicaciones , Índice CPO , Demencia Vascular/complicaciones , Caries Dental/complicaciones , Encuestas de Salud Bucal , Femenino , Hogares para Ancianos , Humanos , Japón/epidemiología , Masculino , Boca Edéntula/complicaciones , Boca Edéntula/epidemiología , Casas de SaludRESUMEN
The caries incidence was clinically examined in 119 children with cleft lip and palate (CLP; 65 male and 54 female; 2 to 14 years of age). At the lower age, the CLP children had more dental caries in the upper teeth than normal children, and, the caries prevalence became higher, with the increase in the age. In both primary and permanent dentitions, the CLP children showed an extremely high caries incidence in the upper anterior teeth, which was related to the presence of cleft. The characteristic oral structures of CLP patients; such as abnormalities of tooth position and axis, the presence of scars, and the absence of vestibular oris, increased the area on the tooth surfaces which afforded the protection from the self-cleaning activity in the mouth, and consequently induced high caries prevalence.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Labio Leporino , Fisura del Paladar , Caries Dental/epidemiología , Adolescente , Niño , Preescolar , Labio Leporino/complicaciones , Fisura del Paladar/complicaciones , Atención Dental para la Persona con Discapacidad , Caries Dental/complicaciones , Femenino , Humanos , Japón/epidemiología , Masculino , Higiene BucalRESUMEN
Structural deformities of deciduous teeth from patients with hypophosphatemic vitamin D-resistant rickets (HVDRR) (1 male and 2 female patients) were examined by means of transmitted light microscopy, contact microradiography, and x-ray microanalysis. Freshly extracted teeth were fixed in formalin and subsequently hemisected longitudinally through the midline. One half was prepared for ground sections and the other half for decalcified sections. Neither gross nor microscopic abnormalities were present in enamel of patients with HVDRR. The concentration of calcium and phosphorus and the calcium/phosphorus ratio of the enamel of patients with HVDRR were nearly equal to those of normal teeth, although the degree of radiopacity was less in HVDRR. On the other hand, numerous microscopic abnormalities in the dentin of patients with HVDRR were found, such as interglobular dentin, wide predentin zones, and tubular defects. The concentration of phosphorus in the dentin of a patient with familial HVDRR was extremely low. Furthermore, formation of reparative dentin was observed at the pulp horn of teeth in patients with HVDRR that had been subjected to definite attrition at the corresponding dentin site.
Asunto(s)
Hipofosfatemia Familiar/patología , Diente Primario/anomalías , Calcio/análisis , Niño , Esmalte Dental/análisis , Esmalte Dental/patología , Dentina/análisis , Dentina/patología , Microanálisis por Sonda Electrónica , Femenino , Humanos , Hipofosfatemia Familiar/genética , Masculino , Microrradiografía , Fósforo/análisis , Diente Primario/análisisRESUMEN
A bacteriocin from serotype c Streptococcus mutans strain C3603 was examined for its inhibitory effect on experimental dental caries in rats infected with S. mutans MT8148R (serotype c). Significant reduction in the incidence of dental caries was found only when bacteriocin was incorporated both in the drinking water and in the diet at a high concentration. However, caries reduction was not as great as expected and the addition of bacteriocin to drinking water alone had no effect on the recovery of S. mutans, plaque deposition or caries incidence. The bacteriocin activity must have been reduced in the oral cavity of rats, and the reasons were examined. Bacteriocin-resistant mutants were not detected and the bacteriocin was not inactivated by saliva. Whereas the bacteriocin did not kill the S. mutans cells grown in a sucrose-containing medium, it completely killed the cells grown in a sucrose-free medium.