[Effect of amoxicillin on the enamel mineralization of SD rats]

Objective: To determine whether amoxicillin had an effect on the enamel mineralization of SD rats. Methods: Eighteen SD rats were randomly divided into three groups. The rats in the control group were given distilled water. The rats in two experimental groups were administered 50 or 100 mg/kg amoxicillin by intragastric administration from day 3 to day 17 after birth. The general condition, the structure of liver and kidney, the enamel surface changes of mandibular first molars and incisors were observed. The changes of Ca/P ratio on enamel surface were analyzed by X-ray energy dispersive spectrometer (EDS). The surface morphology after phosphoric acid treatment was examined by scanning electron microscopy (SEM). Histological changes in the ameloblasts of mandibular incisors were analyzed by hematoxylin and eosin (HE) staining. Results: Compared with the control group, the general conditions as well as liver and kidney structures of SD rats in 50 and 100 mg amoxicillin groups had no significant differences. There was no obvious chalky changes on the first mandibular molars of SD rats in each group. All the incisors in 50 and 100 mg groups showed different degrees of chalkiness in the labial incisal 1/3 enamel. X-ray EDS analysis showed that the Ca/P ratios of occlusal and incisal 1/3 enamel in 50 and 100 mg groups (occlusal 1/3 of mandibular first molars: 1.51±0.03 and 1.52±0.02, incisal 1/3 of mandibular incisors: 1.46±0.01 and 1.43±0.01) was significantly lower than that in the control group (occlusal 1/3 of mandibular first molars: 1.67±0.41, incisal1/3 of mandibular incisors: 1.73±0.07) (P<0.05). However, there was no significant differences in the cervical 1/3 Ca/P ratio of mandibular first molars and incisors among the three groups (mandibular first molars: 1.56±0.04 for control group, 1.59±0.05 for 50 mg group and 1.57±0.04 for 100 mg group; incisors: 1.52±0.02 for control group, 1.47±0.01 for 50 mg group and 1.51±0.03 for 100 mg group) (P>0.05). SEM observation showed that the enamel rods of the first molars and incisors in the 50 and 100 mg group varied in size and arranged disorderly. The spaces between the enamel rods were larger than that in the control group and some areas even appeared large pits. HE staining showed that the gaps between ameloblasts in 50 and 100 mg groups were significantly wider than that in the control group. Conclusions: Intake of amoxicillin during the period of enamel development of SD rats might affect enamel mineralization.

Dental fluorosis in primary teeth: a study in rural schoolchildren in Shaanxi Province, China

OBJECTIVE

The aim of this study was to assess the prevalence and severity of fluorosis in the primary dentition of 7-8-year-old Chinese schoolchildren in areas with fluoride concentrations in the drinking water ranging from 0.35 to 7.6 mg L-).

SUBJECTS AND METHODS

Four hundred and seventy-two children from 13 different schools were divided into four groups according to the fluoride concentration of the drinking water: (A) <or=1.0 mg L-1; (B) 1.1-2.0 mg L-1; (C) 2.1-3.8 mg L-1; and (D) 7.6 mg L-1. Clinical examinations were made under field conditions, and dental fluorosis on the buccal surfaces of all teeth was recorded using the Thylstrup-Fejerskov Index (TFI).

RESULTS

The prevalence of dental fluorosis in primary teeth varied from 6.2% to 96.6% according to the fluoride concentration of the drinking water. The differences of median of TFI scores between all groups were statistically significant (P<0.001) except for groups B and C. No statistically significant difference in the severity of dental fluorosis was observed between genders. The second primary molars were most severely affected by dental fluorosis. Disregarding group A, TFI scores between 3 and 4 were most frequently recorded. Dental fluorosis was symmetrically distributed in both jaws.

CONCLUSION

Dental fluorosis is prevalent in the primary teeth of children living in areas supplied with drinking water with fluoride concentrations higher than 1.0 mg L-1. The primary teeth may act as biomarkers of fluoride exposure. The examination of primary teeth may give an early warning of this condition, and thus, provide a basis for intervention to prevent dental fluorosis in the permanent teeth.

Promotion of ATP and S-140 to ribosome inactivation with camphorin, cinnamomin, and other RNA N-glycosidases

AIM

To study the effect of ATP and extra-ribosomal factors (S-140) on type I and type II RNA N-glycosidases in inactivating ribosome.

METHODS

The activity of ATP and S-140 was determined by characterization of R-fragment in gel. An improved two-step method of cell-free protein synthesis system was used to quantitate the requirements of S-140 in ribosome inactivation.

RESULTS

IC50 ratios of camphorin, gamma-momorcharin, luffin S, luffin A, trichosanthin (type I); and ricin, ricin A-chain; cinnamonin, cinnamomin A-chain (type II) between the absence and presence of ATP and S-140 were 3108, 151, 51, 45, 15; and 47, 7, 26, 12, respectively.

CONCLUSION

The ribosome-inactivating activity of type II ribosome-inactivating proteins, including intact protein and its A-chain, was promoted by ATP and S-140. Camphorin showed a significant difference from cinnamomin in need of ATP and S-140 for such promoting.

[Effects of acidic phosphate fluoride on the protein compositions of acquired pellicle in vitro]

The human enamel powders treated with acidic phosphate fluoride (APF) were used to react with human mixed saliva and purified proteins. Before and after treated with APF, the changes of fluoride content in the enamel and the salivary proteins adsorbed on the enamel surfaces were noticed. The results are as follows: 1. The post-treated enamel fluoride is increased, and the production is fluorapatite besides a little CaF2. 2. No effect of APF on the kind of salivary proteins adsorbed on the enamel is found. 3. The quantity of salivary proteins adsorbed on the enamel is increased in different percentage and the proportion of the proteins on the enamel surface may be changed. Therefore, we believe that these changes must be one of the APF's mechanisms on caries prevention.

[Eye symptoms due to ginseng poisoning]

Ginseng has been used as a tonic for mind and body. A large number of pharmacological studies on ginseng have been done and the variety of effects were shown. In this paper 2 cases of ginseng poisoning has been reported the effects on both eyes were mydriasis and disturbance in accommodation, and the systemic symptoms included dizziness and semiconsciousness, which may be associated with hyperexitability of the sympathetic nerves (adrenergic nerves) due to overdose ginseng.