[ effect of vitamin A on orthodontic tooth movement in male rat]

It has been reported that, administration of excessive vitamin A can lead to profound effects on bone. This vitamin can induce bone degradation by stimulating the formation of mature osteoclasts from precursors. This study was designed to determine the effect of vitamin A on orthodontic tooth movement [OTM] using animal model. A total of 80 male Wister rats were included in this clinical trial. They were divided into eight equal groups. Orthodontic appliances were applied in all the eight groups to deliver an initial force of 60gr for 14 days on the first molar tooth. Six different doses of vitamin A were prepared. In addition to study groups, two control groups were considered as well. One control groups received daily intraperitoneal injections of olive oil and the other did not. Five rats were considered as normal base which received neither appliance nor injection and they were used for histological comparison with all groups. Study groups received 250, 500, 750, 1000, 1750, 2500 IU/Kg doses of vitamin A intraperitoneally each day. OTM was measured at the start and at the end of the study. Blood samples were taken from the heart, and the level of serum alkaline phosphatase was evaluated. After sacrificing the animals, cross-sections of maxilla were prepared by H and E and histological assessments were performed. The descriptive data was analyzed with SPSS version 11 and results were presented by mean and standard deviations. Group differences were analyzed by using One-way ANOVA, followed by Tukey, Kruskal-Wallis and Chi-Square tests. From the eight groups studied the highest amount of OTM was observed in the 2500 IU/Kg group and the least OTM was demonstrated in the 250 IU/Kg study group. Histological assessments showed no difference between vitamin A-treated and control groups. No difference was demonstrated between the groups when comparing the number of osteoclasts, cementoclasts, PDL width, root resorption, and serum alkaline phosphatase [P>0.05]. However significant difference was observed between normal base group and the other eight study groups. Based on the results of this study, despite reported effect of vitamin A on bone tissue, it did not accelerate alveolar bone remodeling and therefore did not change the process of orthodontic tooth movement

effects of depression on endocrine and immune systems

To study the effect of depression on the endocrine and immune systems, 557 male freshman and sophomore medical students [20-30 years old] were given Beck's Depression Inventory. Students with marks 5 or above were selected as the control [n=26] and those with marks of 20 or higher were chosen as the test group [n=27]. All of the students were subjected to the following tests: CBC, differential, total cholesterol [TC], triglycerides [TG], HDL-c, VLDL-c. fibrinogen [Fibr], cortisol [Cort], prolactin [PRL], testosterone[Test], triiodothyronine [T[3]], thyroxine [T[4]], total serum immunoglobulins [Ig], IgA, IgG, IgM, creatine kinase [CK], and C3 and C4 components of the complement system. Results indicated statistically significant increases of the following parameters in the test group as compared with the controls: TC [P < 0.05], LDL-c [P < 0.05], CK [P < 0.025], Fibr [P < 0.01], Test [P < 0.05], Cort [P < 0.025], IgG [P < 0.025] and Ig [P < 0.025]. The results were in accordance with the anticipated hormonal and cell-mediated immunity alterations caused by depression, which affected both cytokines and endorphin levels. In spite of the limited number of subjects used in this study and lack of the dexamethasone suppression test [DST], the overall approach of this study is encouraging; nevertheless, further studies using a larger sample are required