RESUMEN
Our previous studies have shown that dietary xylitol protects against weakening of bone biomechanical properties in experimental postmenopausal osteoporosis. To study whether xylitol preserves bone biomechanics also during aging, a long-term experimental study was performed with rats. Twenty-four male Sprague-Dawley rats were divided into 2 groups. The rats in the control group (NON-XYL group) were fed a basal rat and mouse no. 1 maintenance (RM1) diet, while the rats in the experimental group (XYL group) were continuously fed the same diet supplemented with 10% xylitol (wt/wt). The rats were killed after 20 months. Their femurs were prepared for biomechanical analyses and scanning analyses with peripheral quantitative computed tomography (pQCT). In 3-point bending of the femoral diaphysis, maximum load, maximum elastic load, stiffness, energy absorption, elastic energy absorption, ultimate stress, and yield stress were significantly greater in the XYL group than in the NON-XYL group. This indicates a xylitol-induced improvement of both structural and material strength properties of cortical bone. Accordingly, the maximum load of femoral neck was significantly greater in the XYL group. In the pQCT analysis of femoral diaphysis, cortical bone area, cortical thickness (CtTh) periosteal circumference, and cross-sectional moment of inertia were greater in the XYL group. The endosteal circumference was smaller in the XYL group. In the pQCT analysis of the femoral neck cortical area of the midneck was significantly greater in the XYL group. This data indicates that xylitol exerted beneficial effects on the cross-sectional architecture of the bones. In conclusion, continuous moderate dietary xylitol supplementation leads to improved bone biomechanical properties in aged rats concerning both bone structural and material strength properties.
Asunto(s)
Envejecimiento/fisiología , Huesos/efectos de los fármacos , Huesos/fisiología , Xilitol/farmacología , Animales , Fenómenos Biomecánicos , Huesos/diagnóstico por imagen , Diáfisis/fisiología , Elasticidad , Fémur/fisiología , Masculino , Ratas , Ratas Sprague-Dawley , Valores de Referencia , Resistencia a la Tracción , Tomografía Computarizada por Rayos XRESUMEN
BACKGROUND: Our previous studies have shown that dietary xylitol supplementation protects against the loss of bone mineral after ovariectomy. The ovariectomy-induced decrease in trabecular bone volume is significantly retarded by dietary xylitol. OBJECTIVE: To study whether dietary xylitol can protect against bone loss also during aging, a long-term experimental study was performed with rats. METHODS: Twenty-four male Sprague-Dawley rats were divided into two groups. The rats in the control group were fed a basal RM1 diet, while the rats in the experimental group were continuously fed the same diet supplemented with 10% (w/w) xylitol. The rats were killed after 20 months. Their tibiae were used for the analyses of bone density and trabecular bone volume, and their femurs were used for the scanning analyses with peripheral quantitative computed tomography (pQCT). RESULTS: The tibial density of the xylitol-fed aged group (1.73 +/- 0.14 g/mm(3)) was significantly greater than that of the aged group without xylitol (1.56 +/- 0.14 g/ mm(3)). The trabecular bone volume of the xylitol-fed rats was 21.2 +/- 4.0%. It was significantly greater than that of the rats not receiving xylitol (9.3 +/- 4.3%). The pQCT-measured cortical bone mineral density and the pQTC-measured cortical bone mineral content of the femoral diaphysis were significantly greater in the xylitol-fed group than in the control group. The trabecular bone mineral density and the trabecular bone mineral content of the femoral distal metaphysis were also significantly greater in the xylitol-fed group than in the non-xylitol group. The total bone mineral density and the total bone mineral content of the femoral neck in the xylitol-fed aged group significantly exceeded those in the aged group without xylitol supplementation. CONCLUSIONS: A continuous moderate dietary xylitol supplementation leads to increased bone volume and increased bone mineral content in the long bones of aged rats. This indicates a xylitol-induced protection against aging-related osteoporotic changes.
Asunto(s)
Envejecimiento/fisiología , Densidad Ósea/fisiología , Suplementos Dietéticos , Osteoporosis/prevención & control , Xilitol/farmacología , Animales , Fémur/diagnóstico por imagen , Fémur/fisiopatología , Masculino , Modelos Animales , Probabilidad , Ratas , Ratas Sprague-Dawley , Valores de Referencia , Sensibilidad y Especificidad , Tibia/diagnóstico por imagen , Tibia/fisiopatología , Tomografía Computarizada por Rayos XRESUMEN
The effects of three-month dietary xylitol supplementation on the amounts and hexose contents of acid-soluble collagen as well as on the amounts and fluorescence of collagenase-soluble collagen were studied in healthy and streptozotocin-diabetic male rats. Collagen was extracted from skin samples. In the healthy rats, supplementation with xylitol (10%) increased the hydroxyproline content of the acid-soluble fraction and skin thickness. In diabetic rats receiving and not receiving xylitol, the acid-soluble collagen fraction was markedly lower than in healthy rats. However, its amount was significantly elevated when xylitol had been added to the diet. Supplementation with xylitol caused no changes in the amounts of collagenase-soluble fraction in either healthy or diabetic rats. Supplementation with xylitol (10%) significantly decreased the hexose content of acid-soluble collagen and the fluorescence of the collagenase-soluble fraction in both healthy and diabetic rats. The results indicate that dietary xylitol affects collagen synthesis and collagen glycosylation.
Asunto(s)
Colágeno/metabolismo , Diabetes Mellitus Experimental/metabolismo , Xilitol/farmacología , Animales , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Suplementos Dietéticos , Glicosilación/efectos de los fármacos , Hidroxiprolina/metabolismo , Insulina/sangre , Masculino , Ratas , Ratas Sprague-Dawley , Piel/efectos de los fármacos , Piel/metabolismo , Xilitol/administración & dosificaciónRESUMEN
Xylitol possesses anti-bacterial effects on pneumococci in vitro. To study the effect in vivo, the nostrils of 80 rats were inoculated with pneumococci. Intervention groups (n = 20) received either a xylitol diet or xylitol nasal sprays. The control groups were on a normal diet or had saline sprays. After 3 days, a quantitative bacterial culture and a PCR were done from the mucosal suspension. Neither the mean colony-forming unit counts nor the PCR counts differed statistically significant between the xylitol and control groups. Thus, we found that xylitol had no significant effect on pneumococcal mucosal colonisation.
Asunto(s)
Portador Sano/microbiología , Mucosa Nasal/microbiología , Infecciones Neumocócicas/microbiología , Streptococcus pneumoniae/efectos de los fármacos , Xilitol/farmacología , Administración Intranasal , Animales , Portador Sano/prevención & control , Recuento de Colonia Microbiana , ADN Bacteriano/análisis , Modelos Animales de Enfermedad , Infecciones Neumocócicas/prevención & control , Reacción en Cadena de la Polimerasa/métodos , Ratas , Ratas Sprague-Dawley , Streptococcus pneumoniae/genética , Streptococcus pneumoniae/fisiología , Xilitol/administración & dosificaciónRESUMEN
The effects of 5, 10, and 20% dietary xylitol supplementations on the biomechanical properties, histological architecture, and the contents of collagen, pyridinoline, and deoxypyridinoline in long bones of rats were studied. Tibiae were used for the three-point bending test, and femurs were used for the torsion and loading test of the femoral neck. The 10 and 20% oral xylitol administrations caused a significant increase of tibial stress, femoral shear stress, and stress of the femoral neck as compared with the controls. Parallel, but not significant, effects were also seen in the 5% xylitol supplementation group. No significant differences in strain or Young's modulus of the tibiae were detected between the groups. An increased shear modulus of elasticity in femurs was detected in the 20% supplementation group as compared with the controls. The histomorphometrical data for the secondary spongiosa of the proximal tibia revealed that trabecular bone volume was significantly greater in all dietary xylitol supplementation groups as compared with the controls. The bone volume increased along with increasing xylitol content. No significant differences between the groups were detected concerning the amount of collagen per dry weight of organic matrix, the concentrations of pyridinoline or deoxypyridinoline in collagen, or the ratio of these crosslinks. This suggests no xylitol-dependent selective changes in these structures of bone collagen. In conclusion, dietary xylitol supplementation in rats improves the biomechanical properties of bone and increases the trabecular bone volume dose dependently.
Asunto(s)
Huesos/efectos de los fármacos , Xilitol/farmacología , Administración Oral , Aminoácidos/análisis , Animales , Fenómenos Biomecánicos , Huesos/anatomía & histología , Huesos/química , Huesos/fisiología , Colágeno/análisis , Fémur/anatomía & histología , Fémur/efectos de los fármacos , Fémur/fisiología , Masculino , Ratas , Ratas Wistar , Tibia/anatomía & histología , Tibia/efectos de los fármacos , Tibia/fisiología , Xilitol/administración & dosificaciónRESUMEN
Intestinal degradation of dietary fibre in blanched and microwaved green beans was studied by using a rat experimental model. Content and composition of dietary fibre as well as molecular weight distribution of water-soluble polysaccharides (WSP) were analysed. There was a solubilization and a shift towards lower Mw of mainly uronic acid-containing polysaccharides with repeated microwave treatment in the raw material. Thus, the apparent Mw of water-soluble polysaccharides decreased from approximately 1,550,000 to approximately 300,000. After the beans had been digested the Mw of the WSP was significantly reduced, to approximately 100,000, and the differences in Mw seen between various processed raw materials had been evened out. After fermentation the Mw of the WSP decreased further approximately 10 times. Fibre fermentability was high (approximately 90%) and similar for the various processed beans.
Asunto(s)
Fibras de la Dieta/efectos de la radiación , Digestión/fisiología , Mucosa Intestinal/metabolismo , Microondas , Animales , Fibras de la Dieta/análisis , Fabaceae/efectos de la radiación , Fermentación/fisiología , Peso Molecular , Plantas Medicinales , Ratas , Ratas Wistar , Solubilidad/efectos de la radiación , Ácidos Urónicos/efectos de la radiaciónRESUMEN
The effects of dietary xylitol (xyl) on bone biomechanical properties in ovariectomized rats (ovx) were studied. Forty-two 3-mo-old female Wistar rats were divided into three groups of 14. Rats in two groups were ovariectomized, while those in the control group underwent a sham operation. All rats received a basal diet, and half of the ovx were given an additional 10 g/100 g dietary xyl supplementation. Three months later the rats were killed and their tibias, femurs and humeri were prepared. The tibias were used for analyses of bone density and trabecular bone volume (BV/TV) and for the three-point bending test. The femurs were used for the torsion test and for the loading test of the femoral neck. The humeri were used for analyses of bone ash weight and bone concentrations of calcium and phosphorus. Dietary xyl gave a significant protection against ovariectomy-caused decline of tibial stress in the three-point bending test, of femoral shear stress in the torsion test, and of stress of the femoral neck, without affecting bone elasticity values. Xyl restricted the ovariectomy-caused reduction in bone density, in bone ash weight and in concentrations of bone calcium and phosphorus. Furthermore, trabecular bone loss in ovx was significantly suppressed by dietary xyl. These results indicate that a 10% dietary supplementation of xyl in ovx has a protective effect against the weakening of bone biomechanical properties. This is related to greater BV/TV and maintained bone mineral content.
Asunto(s)
Densidad Ósea/efectos de los fármacos , Xilitol/uso terapéutico , Animales , Fenómenos Biomecánicos , Dieta , Femenino , Osteoporosis/prevención & control , Ovariectomía , Ratas , Ratas Wistar , Xilitol/administración & dosificaciónRESUMEN
The effects of 10% and 20% dietary xylitol supplementation on the biomechanical properties, trabeculation, and mineral content of long bones were studied in streptozotocin-diabetic rats. Forty 3-month-old male Wistar rats were divided randomly into four groups of 10. Rats in three groups were administered a single injection of streptozotocin (50 mg/kg body weight) to induce type I diabetes, while animals in the fourth group were given a sham injection of physiological saline. The sham-injected group and one of the streptozotocin-diabetic groups were fed the basal diet, while the two diabetic groups were fed the same diet supplemented with 10% and 20% xylitol (wt/wt). After 3 months, the rats were killed and the long bones were prepared for analysis. The 10% and 20% dietary xylitol supplementation significantly prevented the type I diabetes-induced decrease in the mechanical stress resistance of the tibia in the three-point bending test, the shear stress of the femur in the torsion test, and the stress resistance of the femoral neck in the loading test. No statistically significant differences were found between any groups in the values for strain or Young's modulus in the three-point bending test, or in the values for the shear modulus of elasticity in the torsion test. These findings indicate that dietary xylitol protects against the weakening of the bone strength properties of both cortical and trabecular bone without affecting the elastic-plastic properties. Supplementation with 10% and 20% dietary xylitol significantly prevented the type I diabetes-induced decrease of humeral ash weight and tibial density. Histomorphometric data for the secondary spongiosa of the proximal tibia showed that 10% and 20% dietary xylitol supplementation also significantly prevented the type I diabetes-induced loss of trabecular bone volume. In conclusion, dietary xylitol supplementation protects against the weakening of bone biomechanical properties in streptozotocin-diabetic rats. This is related to the preserved bone mineral content and preserved trabecular bone volume.
Asunto(s)
Diabetes Mellitus Experimental/fisiopatología , Suplementos Dietéticos , Osteoporosis/prevención & control , Xilitol/administración & dosificación , Xilitol/uso terapéutico , Animales , Glucemia/efectos de los fármacos , Glucemia/metabolismo , Densidad Ósea/efectos de los fármacos , Huesos/efectos de los fármacos , Huesos/patología , Fuerza Compresiva/efectos de los fármacos , Diabetes Mellitus Experimental/inducido químicamente , Diabetes Mellitus Experimental/tratamiento farmacológico , Diabetes Mellitus Tipo 1/inducido químicamente , Diabetes Mellitus Tipo 1/tratamiento farmacológico , Diabetes Mellitus Tipo 1/fisiopatología , Elasticidad/efectos de los fármacos , Elementos Químicos , Ingestión de Energía/efectos de los fármacos , Ingestión de Energía/fisiología , Cuello Femoral/efectos de los fármacos , Cuello Femoral/fisiología , Húmero/efectos de los fármacos , Insulina/sangre , Masculino , Minerales , Osteoporosis/tratamiento farmacológico , Osteoporosis/fisiopatología , Resistencia Física/efectos de los fármacos , Ratas , Ratas Wistar , Estreptozocina , Estrés Mecánico , Tibia/efectos de los fármacos , Anomalía Torsional/fisiopatología , Aumento de Peso/efectos de los fármacos , Aumento de Peso/fisiologíaRESUMEN
Levels of mutans streptococci in plaque adjacent to orthodontic brackets retained with a glass ionomer cement (GIC) (Ketac-Cem) and a resin-based composite (CR) (Concise) were investigated, using the split mouth technique in 11 patients who, before treatment, had more than 10(5) CFU of these microorganisms. After full-term orthodontic treatment (mean 9.5 months), the percentage of mutans streptococci of total CFU count in plaque was lower adjacent to GIC-retained brackets (mean 3.9) than adjacent to CR-retained brackets (6.7), but the difference was not statistically significant. Two subjects harbored S. sobrinus. These subjects were the only ones who developed incipient caries during the orthodontic treatment. Incipient lesion formation occurred only adjacent to CR-retained brackets. This suggests that in patients who have relatively high salivary levels of mutans streptococci before treatment and especially in those who harbor S. sobrinus, the use of GIC for bonding may prevent incipient caries formation during orthodontic treatment.
Asunto(s)
Bisfenol A Glicidil Metacrilato , Placa Dental/microbiología , Cementos de Ionómero Vítreo , Óxido de Magnesio , Aparatos Ortodóncicos , Cemento de Policarboxilato , Streptococcus mutans/aislamiento & purificación , Óxido de Zinc , Adolescente , Niño , Recuento de Colonia Microbiana/estadística & datos numéricos , Caries Dental/prevención & control , Pruebas de Actividad de Caries Dental/estadística & datos numéricos , Humanos , Maloclusión Clase I de Angle/microbiología , Maloclusión Clase I de Angle/terapia , Aparatos Ortodóncicos/estadística & datos numéricos , Estadísticas no Paramétricas , Streptococcus sobrinus/aislamiento & purificaciónRESUMEN
The effects of 10% dietary xylitol supplementation in ovariectomized rats were studied on the degradation of bone organic and inorganic structures. The osseal concentrations of hydroxyproline, pyridinoline, and deoxypyridinoline were analyzed by high-performance liquid chromatography. Bone resorption was measured in [3H]tetracycline-prelabeled rats by urinary excretion of 3H, and by the amount of 3H preserved in bone. Bone trabeculation was measured by a computer image analyzer from sections stained by the method of von Kossa. The amount of collagen in bone organic fraction was lower in ovariectomized rats as compared with the sham-operated controls. This most likely is partly a consequence of an increased resorption, and partly a consequence of a higher proportion of immature periosteal bone in the ovariectomized animals, leading to a higher ratio of noncollagenous protein to collagen. The number of pyridinium crosslinks was lower in proportion, indicating no selective changes in the structure of collagen. Dietary xylitol significantly retarded the ovariectomy-associated decrease in the relative amount of collagen and the number of its mature crosslinks. Ovariectomy doubled the excretion of 3H and caused a significant decrease in the amount of 3H preserved in bone; both these changes were significantly retarded by the 10% dietary xylitol supplementation. Ovariectomy significantly decreased the volume of bone trabeculae, but this effect was also significantly inhibited by the xylitol supplementation in the diet. In conclusion, these findings suggest a dietary xylitol-induced normalizing effect on the rate of bone turnover in ovariectomized rats.
Asunto(s)
Desarrollo Óseo/efectos de los fármacos , Resorción Ósea/prevención & control , Huesos/fisiopatología , Ovariectomía , Xilitol/farmacología , Animales , Biomarcadores/sangre , Resorción Ósea/etiología , Huesos/efectos de los fármacos , Huesos/patología , Colágeno/orina , Femenino , Alimentos Fortificados , Ratas , Ratas Sprague-Dawley , Tetraciclina/farmacocinética , Tibia , Aumento de Peso , Xilitol/administración & dosificaciónRESUMEN
A xylitol-induced reduction in dentin formation has been observed in molars of post-weanling rats, but the effect in older animals with a slower rate of secondary dentinogenesis has not been investigated. We examined the effects of different concentrations of dietary xylitol on dentinogenesis in molars of young adult rats. The control group received a commercial basal diet, while for the other 3 groups, the same diet was supplemented with 5, 10 and 20% of xylitol. After 8 weeks, dentin thickness beneath the main fissures in the mandibular 1st and 2nd molars was measured. The final body weights did not differ between the groups. Dentin formation in the 1st molars of the 10 and 20% xylitol groups was significantly lower as compared to the controls, whereas no difference was found between these 2 groups. In conclusion, dietary xylitol reduces dentin formation in young adult rats in spite of the slow rate of dentinogenesis.
Asunto(s)
Dentinogénesis/efectos de los fármacos , Edulcorantes/farmacología , Xilitol/farmacología , Animales , Esmalte Dental/ultraestructura , Dentina/ultraestructura , Dentina Secundaria/efectos de los fármacos , Dentina Secundaria/ultraestructura , Carbohidratos de la Dieta/administración & dosificación , Carbohidratos de la Dieta/farmacología , Masculino , Diente Molar , Ratas , Ratas Wistar , Edulcorantes/administración & dosificación , Xilitol/administración & dosificaciónRESUMEN
The aim of the present study was to compare the ability of four dietary polyols to reduce bone resorption. Urinary excretion of 3H radioactivity from [3H]tetracycline-prelabeled rats was used as a marker of bone resorption. After prelabeling, the rats were divided randomly into five groups of 10, and fed for 1 mo a nonpurified diet that was supplemented in four groups with either xylitol, sorbitol, D-mannitol or erythritol, respectively, to give a polyol concentration of 1 mol/kg. Xylitol (42%), sorbitol (44%) and to a lesser degree D-mannitol (23%) decreased the excretion of 3H relative to the basal diet. The erythritol group, however, did not differ from the controls. Sorbitol caused continuous diarrhea, whereas in the other groups, intestinal adaptation took place during the 1st wk of polyol feeding. In conclusion, dietary xylitol, sorbitol and to a lesser degree D-mannitol supplementations in rats retard bone resorption, whereas dietary erythritol has no effect.
Asunto(s)
Resorción Ósea/fisiopatología , Alcoholes del Azúcar/farmacología , Animales , Resorción Ósea/prevención & control , Dieta , Eritritol/administración & dosificación , Eritritol/farmacología , Masculino , Manitol/administración & dosificación , Manitol/farmacología , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Sorbitol/administración & dosificación , Sorbitol/farmacología , Relación Estructura-Actividad , Alcoholes del Azúcar/administración & dosificación , Tritio/orina , Aumento de Peso/efectos de los fármacos , Xilitol/administración & dosificación , Xilitol/farmacologíaRESUMEN
The effects of dietary calcium deficiency and subsequent replenishment of the diet with calcium alone or with xylitol were studied. Thirty 3-week-old Wistar rats were labelled with an i.p. tetracycline injection. Twenty rats were fed a diet with 0.026% calcium (Ca-deficient); 10 received a 0.5% Ca diet (controls). After 3 weeks the tetracycline labelling was repeated. Replenishment of the diet was introduced for Ca-deficient rats, and 10 received additional 5% xylitol in the diet. After 4 weeks the labelling was repeated and the animals were decapitated. Dentine formation was measured by the tetracycline stripes in the lower first and second molars. Calcium deficiency during the first 3 weeks reduced dentine formation. In the control and xylitol groups, a much smaller amount of dentine was formed during the recovery period. With Ca alone, dentine formation was faster than in the controls or Ca-xylitol group and did not differ from the Ca-deficient period. These results indicate that in rat molars the odontoblasts can accelerate the rate of dentine formation when calcium is restored to the diet, at least during primary dentinogenesis. This effect was not seen when 5% xylitol was added to the replenishment diet.
Asunto(s)
Calcio/deficiencia , Dentinogénesis , Animales , Calcio de la Dieta/farmacología , Dentinogénesis/efectos de los fármacos , Masculino , Ratas , Ratas Wistar , Xilitol/farmacologíaRESUMEN
The effects of 5, 10, and 20% dietary xylitol supplementations on the resorption of bone were studied. The resorption was measured by the urinary excretion of [3H] radioactivity from [3H]tetracycline-prelabeled rats. The 10 and 20% oral xylitol administrations caused a significant decrease in the excretion of [3H] as compared with the control group with no xylitol supplementation. The effect was detected as early as 2 days after the beginning of xylitol-feeding and was maintained throughout the experimental period of 31 days. The retarding effect on bone resorption was about 25% in the 10% xylitol group, about 40% in the 20% xylitol group, and undetectable in the 5% xylitol group. The amount of preserved [3H] radioactivity in the tibiae of the 10 and 20% xylitol groups after the experiment clearly exceeded the values of the control group. The mechanism of the retarded bone resorption caused by dietary xylitol still remains obscure, but an increased absorption of calcium may be involved. In conclusion, dietary xylitol supplementation in rats seems to retard the bone resorption in a dose-dependent way. The effect is achieved rapidly and is maintained at least over a period of 1 month xylitol feeding.
Asunto(s)
Resorción Ósea/tratamiento farmacológico , Xilitol/uso terapéutico , Administración Oral , Análisis de Varianza , Animales , Dieta , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Marcaje Isotópico , Masculino , Ratas , Ratas Wistar , Tetraciclina/química , Tritio/metabolismo , Xilitol/administración & dosificación , Xilitol/farmacologíaRESUMEN
Thirty-six 3-month-old female Wistar rats were labelled with a single intraperitoneal tetracycline injection. Twenty-four animals were subsequently ovariectomized, while the control group of 12 animals underwent sham operations. All animals received the basal Ewos R3 diet and half of the ovariectomized animals (n = 12) were given an additional 5% dietary xylitol supplementation. Three months later, following the collection of blood and urine, the animals were killed by decapitation. The tibiae were detached and prepared for chemical and other studies. The weight and density of the tibiae were measured. The right tibiae were dried and pulverized for chemical analysis of calcium, phosphorus and citric acid. The total inorganic fraction was determined by ashing the powdered bone. The left tibiae were cross-sectioned at the tibio-fibular junctions for the measurement of the width of periosteally formed bone, which was identified by tetracycline fluorescence. The examination of mineral content of bone was performed by scanning electron microscopy, using an electron probe microanalytic technique. The results indicate that the supplementation of the diet with 5% xylitol had a protective effect against the loss of bone mineral after ovariectomy in the rat. This was clearly seen in tibial density and in the inorganic fraction of the bone, and in the concentrations of bone Ca and phosphorus. Ovariectomy caused a doubling in periosteal bone formation relative to the controls, whereas the growth of the periosteally formed bone was somewhat reduced following xylitol supplementation as compared with ovariectomy alone.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Huesos/química , Huesos/metabolismo , Calcio/análisis , Dieta , Ovariectomía , Fósforo/análisis , Xilitol/administración & dosificación , Animales , Huesos/efectos de los fármacos , Calcio/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Osteoporosis/metabolismo , Fósforo/metabolismo , Ratas , Ratas Wistar , Xilitol/farmacologíaRESUMEN
Twenty-nine 3-month-old female Wistar rats were labeled by means of a single intraperitoneal tetracycline injection. Nineteen animals were subsequently ovariectomized, whereas a control group of 10 animals underwent sham operations. All the animals received the basal diet, and 10 of the ovariectomized animals were given an additional dietary xylitol supplementation (5%). Three months later the animals were killed by decapitation, and dentinal apposition on the molars was measured. The results indicate that supplementation of the diet with 5% xylitol had an attenuating effect on the enhanced dentin formation caused by ovariectomy, but the mechanism remains unsolved.
Asunto(s)
Dentina/efectos de los fármacos , Dentinogénesis/efectos de los fármacos , Ovariectomía , Xilitol/farmacología , Animales , Peso Corporal , Dentina/fisiología , Dieta , Femenino , Fluorescencia , Diente Molar , Ovario/fisiología , Ratas , Ratas Wistar , Tetraciclina , Xilitol/administración & dosificaciónRESUMEN
Dietary xylitol has previously been found to promote the content of calcium and minerals of the bone during rehabilitation following dietary calcium deficiency and during a normocalcemic diet in rats. This in vivo experiment was performed in order to study whether a short-term dietary xylitol supplementation affects bone resorption and calcium incorporation into bone during two different experiments utilizing either calcium-deficient or normocalcemic diets. Xylitol reduced bone resorption measured by the urinary excretion of 3H radioactivity both during calcium-deficient and normocalcemic diets. However xylitol reduced vitamin D levels only during calcium deficiency, indicating that the decreased bone dissolution was not associated with changes in 1,25(OH)2D3 concentration alone. Dietary xylitol did not alter 45Ca incorporation into bone, although this does not exclude the possibility that xylitol may have caused alterations in bone apposition. These results suggest that a short-term xylitol ingestion retards bone resorption in the rat.
Asunto(s)
Resorción Ósea/prevención & control , Xilitol/farmacología , Animales , Calcitriol/sangre , Calcio/deficiencia , Dieta , Masculino , Ratas , Ratas Wistar , Xilitol/metabolismoRESUMEN
Thirty-six 3-week-old male Wistar rats were labeled with a single intraperitoneal tetracycline injection. Twenty-four of them were then fed a Ca-deficient basal diet for 3 weeks, while the control group received the basal diet supplemented with CaCO3 (12 g/kg). The tetracycline labeling was then repeated and six animals in each group were decapitated. The diet of the remaining formerly Ca-deficient animals was returned to normal, and half the test rats also received xylitol supplementation (50 g/kg). After 4 weeks of rehabilitation the labeling was repeated and the animals were decapitated and their tibias were prepared. The tibias were measured in terms of weight and density and cross sections were prepared for the examination of mineral content. Bone element analysis was performed by scanning electron microscopy with electron-probe microanalysis, examining separately the bone areas formed during the various dietary periods. Areas of the former Ca-deficient and newly formed cortical bone were identified by tetracycline fluorescence under ultraviolet light, and the amount of cortical bone in each group was measured. The mineralization-promoting effect of dietary xylitol as compared with CaCO3 supplementation alone was seen more clearly in the newly formed periosteal bone than in remineralization of the formerly Ca-deficient bone, the concentrations of Ca and P being significantly elevated (P < 0.05), as also was the total mineral content (P < 0.01). The cortical bone volume was similar following the CaCO3 and CaCO3 + xylitol supplementations, suggesting unaltered formation of the organic matrix. The results show that the effect of xylitol on bone during dietary Ca rehabilitation particularly concerns newly formed bone mineral.(ABSTRACT TRUNCATED AT 250 WORDS)
Asunto(s)
Calcificación Fisiológica/fisiología , Tibia/fisiología , Xilitol/farmacología , Animales , Densidad Ósea , Remodelación Ósea , Calcio/análisis , Carbonato de Calcio/administración & dosificación , Carbonato de Calcio/farmacología , Relación Dosis-Respuesta a Droga , Microanálisis por Sonda Electrónica , Alimentos Fortificados , Masculino , Microscopía Electrónica de Rastreo , Tamaño de los Órganos , Fósforo/análisis , Ratas , Ratas Wistar , Tibia/anatomía & histología , Tibia/química , Xilitol/administración & dosificaciónRESUMEN
Young male Wistar rats were fed on a Ca-deficient diet for 3 weeks, after which dietary Ca was restored with either CaCO3 or CaCO3 + xylitol (5% per weight). Citric acid, Ca, Mg, Zn and P were determined in the tibia and femur at the beginning and after 2 and 4 weeks of rehabilitation, and serum and urinary citric acid and serum 1,25(OH)2D3, parathyroid hormone (PTH) and calcitonin were measured at the same points in time. The diminished bone Ca (p < 0.001) after 3 weeks of deficiency did not reduce the bone citric acid concentration, although serum citrate increased markedly. Simultaneously the serum 1,25(OH)2D3 concentration more than doubled and PTH increased (p < 0.01). Rehabilitation with CaCO3 + xylitol reduced the 1,25(OH)2D3 concentration to below the control level (p < 0.05), while serum citric acid remained elevated. CaCO3 alone normalized the elevated hormone and citric acid levels in the serum. Dietary CaCO3 and CaCO3 + xylitol normalized the PTH concentration equally well. The gain in bone Ca after 4 weeks of rehabilitation was significantly greater when xylitol was added compared with CaCO3 alone (p < 0.05). Only the 4-week CaCO3 + xylitol group attained the bone Ca concentration of the controls. Xylitol supplementation seems to affect the serum citric acid concentration independent of 1,25(OH)2D3 and PTH concentrations. The elevated citric acid concentration could be associated with increasing bone Ca.
Asunto(s)
Calcitonina/sangre , Calcitriol/sangre , Calcio/deficiencia , Citratos/metabolismo , Hormona Paratiroidea/sangre , Xilitol/farmacología , Animales , Huesos/metabolismo , Carbonato de Calcio/farmacología , Citratos/sangre , Citratos/orina , Ácido Cítrico , Masculino , Ratas , Ratas WistarRESUMEN
Eighteen caries-active adolescents, each having both a class II conventional amalgam (Dispersalloy) and a glass-ionomer (Ketac Silver) tunnel restoration of the same age placed on a contralateral tooth, were part of a 3-year clinical study. At the 1- and 2-year examinations all test restorations were assessed as acceptable in all patients. At the 3-year assessment three amalgam restorations failed due to recurrent caries, and one glass-ionomer restoration failed due to marginal ridge fracture. During the entire study period, the requirement of restorative therapy because of primary proximal caries was significantly reduced (p < 0.05) on tooth surfaces adjacent to the glass-ionomer restorations as compared with that on tooth surfaces adjacent to the amalgam restorations.