Caries inhibitory activity of cacao bean husk extract in in-vitro and animal experiments.

Cacao bean husk extract (CBH) was examined for inhibitory effects on the caries-inducing properties of mutans streptococci in vitro and on caries development in specific pathogen-free Sprague-Dawley rats infected with mutans streptococci. CBH reduced the growth rate of almost all oral streptococci examined, which resulted in the reduction of acid production. Furthermore, insoluble glucan synthesis by the glucosyltransferases from Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 was significantly inhibited by CBH. Hence, the sucrose-dependent cell adherence of mutans streptococci was also depressed by CBH. The administration of CBH in drinking water resulted in significant reductions of caries development and dental plaque accumulation in rats infected with either Strep. sobrinus 6715 or Strep. mutans MT8148R, and the minimum cariostatic concentration was 1.0 mg/ml. These results indicate that CBH possesses powerful anticariogenic potential.

Treatment of solitary small hepatocellular carcinoma: consideration of hepatic functional reserve and mode of recurrence.

BACKGROUND/AIMS: Hepatocellular carcinoma (HCC) recurs frequently after initial treatment. The subsequent prognosis varies with the mode of recurrence. Some patients die of hepatic failure even though the HCC is controlled. We consider the clinical stage (CS), using the modified Child-Pugh classification, to be an important factor influencing the prognosis of these patients. METHODOLOGY: To determine the most effective treatment for HCC, we examined 105 patients with solitary small HCC who were followed-up for more than 1 year after initial treatment. All of them were judged to be cured according to imaging or histological studies. The initial treatments were hepatic resection (n = 43), percutaneous ethanol injection therapy (PEIT, n = 33), and percutaneous microwave coagulation therapy (PMCT, n = 29). The modes of recurrence were divided into intrahepatic metastasis (IM) and multicentric occurrence (MO). RESULTS: Prognosis of MO was superior to that of IM in CS I patients, but there was no difference in prognosis between these modes in CS II. The hepatic resection group had more MO recurrences in CS I patients and more IM recurrences in CS II patients. IM developed frequently after PEIT and PMCT, regardless of the CS. Prognosis with hepatic resection was superior to that of the other treatments in CS I patients, but there was no difference in prognosis among the 3 treatment modalities in CS II patients. CONCLUSIONS: These data indicate that hepatic resection is the first choice for treating HCC in CS I patients, and that PEIT or PMCT is preferable for CS II patients.

Inhibitory effects of oolong tea extract on caries-inducing properties of mutans streptococci.

The inhibitory effects of oolong tea extract (OTE) on the caries-inducing properties of mutans streptococci were examined in vitro. OTE reduced the rate of acid production by mutans streptococci accompanied with the retardation of growth rate of mutans streptococci, while the action by chromatographically isolated oolong tea polyphenol (OTF6) was weak. On the other hand, both oolong tea products decreased cell surface hydrophobicity of almost all the oral streptococci examined in the present study, and also induced cellular aggregation of Streptococcus mutans, Streptococcus oralis, Streptococcus sanguis or Streptococcus gordonii. In these reactions, OTF6 showed a more pronounced activity than OTE. Furthermore, the oolong tea products inhibited the adherence of mutans streptococci to saliva-coated hydroxyapatite. These results suggest that OTF6 may inhibit bacterial adherence to the tooth surfaces by reducing the hydrophobicity of mutans streptococci, and OTE may inhibit caries-inducing activity of mutans streptococci by reducing the rate of acid production.

Comparison of the cariostatic effects between regimens to administer oolong tea polyphenols in SPF rats.

The cariostatic effect of oolong tea polyphenols administered according to several regimens was examined in specific pathogen-free (SPF) Sprague-Dawley rats given both a diet containing 20% sucrose and infected with S. sobrinus 6715. The crude preparation (OTE) of oolong tea polyphenols showed the most prominent effect on caries reduction in SPF rats when OTE was administered in the drinking water beginning 1 day prior to the inoculation of S. sobrinus 6715, when compared with chromatographically isolated polyphenol fractions (OTF1 and OTF6) of OTE. Reduction in caries development was found even when OTE was given 1 day after inoculation of the organism. OTE was shown to significantly inhibit dental caries in rats at the concentrations of either more than 5 microg/ml in drinking water or more than 10 microg/g in diet. OTF1 and OTF6 also showed significant inhibition of caries induction, with the minimum inhibitory concentration of OTF6 being 50 microg/ml in drinking water and the minimum inhibitory concentration of OTF1 being 100 microg/g in diet. These results indicate that cariostatic activity of OTE was effective even after the establishment of S. sobrinus in the oral cavity and was more effective in drinking water than in diet. Furthermore, OTE may contain some anticaries substances that affect the virulence of S. sobrinus other than glucosyltransferases.

Oolong tea polyphenols inhibit experimental dental caries in SPF rats infected with mutans streptococci.

An extract of oolong tea (semifermented tea leaves of Camellia sinensis) and its chromatographically isolated polyphenolic compound was examined for in vitro inhibitory effects on glucosyltransferases (GTases) of mutans streptococci and on caries development in Sprague-Dawley rats infected with mutans streptococci. The samples showed no detectable effect on the growth of mutans streptococci. However, insoluble glucan synthesis from sucrose by the GTases of Streptococcus mutans MT8148R and Streptococcus sobrinus 6715 was markedly inhibited, as was sucrose-dependent cell adherence of these mutans streptococci. The administration of the oolong tea extract and the isolated polyphenol compound into diet 2000 and drinking water resulted in significant reductions in caries development and plaque accumulation in the rats infected with mutans streptococci. The active components in the oolong tea extract were presumptively identified as polymeric polyphenols which were specific for oolong tea leaves. These results indicate that the oolong tea polyphenolic compounds could be useful for controlling dental caries.

The occurrence of interglobular dentin in incisors of hypophosphatemic mice fed a high-calcium and high-phosphate diet.

The incisor dentin of hypophosphatemic (Hyp) mice was examined histopathologically to determine whether the multiple occurrences of interglobular dentin would be influenced by the serum phosphate level. Both normal and Hyp mice (12 weeks of age) were divided into two groups. The mice in one group were given a control diet (1.42% Ca, 1.16% P) and the other a high-calcium and high-phosphate diet (2.00% Ca, 3.00% P) for 30 days. Blood was collected from the mice every fifth day for measurement of the calcium and phosphate concentrations in serum. Both ground and decalcified cross-sections were prepared from incisors from the mandible and maxilla for microscopic examination. The levels of serum Ca and P were almost constant in normal mice, regardless of diet. On the other hand, serum P levels in Hyp mice fed the control diet were significantly lower than those in normal mice. The ten days' feeding of the high-Ca/-P diet significantly elevated the serum P level in Hyp mice, and it reached a level similar to that of the normal mice. However, histopathological examination showed no significant changes in incisor dentin of Hyp mice fed the high-Ca/-P diet, and interglobular dentin still occurred. These results suggest that the multiple formations of interglobular dentin, which is the most outstanding feature of X-linked hypophosphatemic vitamin-D-resistant rickets, are not influenced in Hyp mice by the short-time normalization of the serum phosphate level.

[Inhibitory effects of a hot water extract from Japanese tea on the cell growth of mutans streptococci].

This study was undertaken to examine the effect of a hot water extract from Japanese tea on the cellular growth of mutans streptococci in vitro. The extract contained polyphenol compounds, mainly catechin derivatives. Few fluoride components were contained in the extract. Streptococcus mutans MT8148R (serotype c) and S. sobrinus MT6715 (serotype g) strains were used in the present study. The organisms (10-10(7) CFU/ml) were cultured in brain heart infusion (BHI) and tryptose phosphate (TP) broths containing the tea extract (0-8 mg/ml). After incubation for 24-48 hours the cell numbers in the cultures were determined. Furthermore, cell growth of these strains on BHI agar plates containing the extract (0-2 mg/ml) were examined. The results obtained were as follows: 1. The tea extract (2-8 mg/ml) in BHI broth inhibited remarkably the growth of S. mutans and S. sobrinus (inoculum size; 10(6) CFU/ml). No difference in susceptibility to the tea extract between S. mutans and S. sobrinus was noted. 2. The cell growth of both strains in TP broth was inhibited by the tea extract. However S. sobrinus was found to be more sensitive to the extract than S. mutans. 3. Growth of S. sobrinus cells on the BHI agar plate was suppressed by the tea extract more effectively than that of S. mutans. These results suggest that the tea extract would be useful as an anti-cariogenic agent.

Structural deformities of deciduous teeth in patients with hypophosphatemic vitamin D-resistant rickets.

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.