Effect of xylitol and fluoride on enamel erosion in vitro

This study aimed to determine the anti-erosive effects of xylitol, fluoride and a xylitol/fluoride combination used as an additive in an acidic drink or as mouthrinse after enamel was exposed to an acidic drink, in vitro. Human third molars were divided into 7 groups (A-G). Samples from groups A to D were immersed for 5 min in orange juice only (A), orange juice plus either 25% xylitol (B), F(-) 1 ppm (C) or a 25% xylitol/F(-) 1 ppm combination (D), respectively. Samples from groups E to G were immersed in orange juice for 5 min and then in either 40% xylitol (E), F(-) 227 ppm (F) or a 40% xylitol/F(-) 227 ppm combination (G), for 1 min respectively. This process was performed four times daily for 14 days. Mineral loss was determined from the lesion depth and surface hardness. Erosion depth progressively increased in all groups, except E, where erosion depth was significantly lower than group A. Surface microhardness progressively decreased in all groups, except E, where hardness was significantly higher than group A. This study demonstrated that addition of xylitol, fluoride or a xylitol/fluoride combination to an acidic drink or post-treatment with fluoride or a xylitol/fluoride combination could reduce, but not prevent, enamel erosion.     

Neuroprotection of N-benzylcinnamide on scopolamine-induced cholinergic dysfunction in human SH-SY5Y neuroblastoma cells

Alzheimer's disease, a progressive neurodegenerative disease, affects learning and memory resulting from cholinergic dysfunction. Scopolamine has been employed to induce Alzheimer's disease-like pathology in vivo and in vitro through alteration of cholinergic system. N-benzylcinnamide(PT-3), purified from Piper submultinerve, has been shown to exhibit neuroprotective properties against amyloid-β-induced neuronal toxicity in rat cortical primary cell culture and to improve spatial learning and memory of aged rats through alleviating oxidative stress. We proposed a hypothesis that PT3 has a neuroprotective effect against scopolamine-induced cholinergic dysfunction. PT-3(125–200 n M) pretreatment was performed in human neuroblastoma SH-SY5 Y cell line following scopolamine induction. PT-3(125–200 n M) inhibited scopolamine(2 m M)-induced generation of reactive oxygen species, cellular apoptosis, upregulation of acetylcholinesterase activity, downregulation of choline acetyltransferase level, and activation of p38 and JNK signalling pathways. These findings revealed the underlying mechanisms of scopolamine-induced Alzheimer's disease-like cellular dysfunctions, which provide evidence for developing drugs for the treatment of this debilitating disease.     

Atovaquone-Proguanil Remains a Potential Stopgap Therapy for Multidrug-Resistant Plasmodium falciparum in Areas along the Thai-Cambodian Border

Our recent report of dihydroartemisinin-piperaquine failure to treat Plasmodium falciparum infections in Cambodia adds new urgency to the search for alternative treatments. Despite dihydroartemisinin-piperaquine failure, and higher piperaquine 50% inhibitory concentrations (IC₅₀s) following reanalysis than those previously reported, P. falciparum remained sensitive to atovaquone (ATQ) in vitro. There were no point mutations in the P. falciparum cytochrome b ATQ resistance gene. Mefloquine, artemisinin, chloroquine, and quinine IC₅₀s remained comparable to those from other recent reports. Atovaquone-proguanil may be a useful stopgap but remains susceptible to developing resistance when used as blood-stage therapy.     

Migraine in Thai children: prevalence in junior high school students

A cross-sectional study to determine the prevalence of migraine in seventh grade Thai students in 4 junior high schools in Bangkok, Thailand, according to the diagnostic criteria of the second edition of the Classification of Headache of the International Headache Society was conducted in July 2004. The study included a screening self-administered questionnaire and face-to-face interview with physical examination. The diagnosis of migraine was made and confirmed by 2 pediatric neurologists. All of 1789 students in participating schools completed the questionnaire. After 2 interviews, 248 students (13.8%) were diagnosed with migraine. The prevalence in girls was higher than that in boys (16.2% vs 11.7%). Migraine as having aura was diagnosed in 34 students (13.7%). One student had sporadic hemiplegic migraine. Among 248 children, 176 (71%) reported the duration of headache between 1 and 2 hours. The leading precipitating factor of migraine was the stress related to daily school activities (17.7%). There were 32 students (12.9%) with frequent and intense headache who were referred to their primary physicians for further management. This study had disclosed a high prevalence of migraine in seventh grade Thai students in Bangkok City and reflected the existing burden of this illness in Thai students.     

Fluorine-18-labeled benzamide analogues for imaging the sigma2 receptor status of solid tumors with positron emission tomography

A series of fluorine-containing benzamide analogs was synthesized and evaluated as candidate ligands for positron emission tomography (PET) imaging of the sigma-2 (sigma2) receptor status of solid tumors. Four compounds having a moderate to high affinity for sigma2 receptors and a moderate to low affinity for sigma-1 (sigma1) receptors were radiolabeled with fluorine-18 via displacement of the corresponding mesylate precursor with [18F]fluoride. Biodistribution studies in female Balb/c mice bearing EMT-6 tumor allografts demonstrated that all four F-18-labeled compounds had a high tumor uptake (2.5-3.7% ID/g) and acceptable tumor/normal tissue ratios at 1 and 2 h post-i.v. injection. An analysis of the chemistry and biodistribution data suggested that N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-[18F]-fluoroethoxy)-5-methylbenzamide ([18F]3c) and N-(4-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)butyl)-2-(2-[18F]-fluoroethoxy)-5-iodo-3-methoxybenzamide ([18F]3f) are acceptable compounds for imaging the sigma2 receptor status of solid tumors.     

Effects of physical exercise on depression, neuroendocrine stress hormones and physiological fitness in adolescent females with depressive symptoms

BACKGROUND: Regular physical exercise may improve a variety of physiological and psychological factors in depressive persons. However, there is little experimental evidence to support this assumption for adolescent populations. We conducted a randomized controlled trial to investigate the effect of physical exercise on depressive state, the excretions of stress hormones and physiological fitness variables in adolescent females with depressive symptoms. METHODS: Forty-nine female volunteers (aged 18-20 years; mean 18.8 +/- 0.7 years) with mild-to-moderate depressive symptoms, as measured by the Centre for Epidemiologic Studies Depression (CES-D) scale, were randomly assigned to either an exercise regimen or usual daily activities for 8 weeks. The subjects were then crossed over to the alternate regimen for an additional 8-week period. The exercise program consisted of five 50-min sessions per week of a group jogging training at a mild intensity. The variables measured were CES-D rating scale, urinary cortisol and epinephrine levels, and cardiorespiratory factors at rest and during exercise endurance test. RESULTS: After the sessions of exercise the CES-D total depressive score showed a significant decrease, whereas no effect was observed after the period of usual daily activities (ANOVA). Twenty-four hour excretions of cortisol and epinephrine in urine were reduced due to the exercise regimen. The training group had a significantly reduced resting heart rate and increased peak oxygen uptake and lung capacity. CONCLUSIONS: The findings of this study suggest that a group jogging exercise may be effective in improving depressive state, hormonal response to stress and physiological fitness of adolescent females with depressive symptoms.     

Alveolar bone changes in autogenous tooth transplantation

Malignant hyperthermia (MH) is a pharmacogenetic disorder of skeletal muscle that presents as a hypermetabolic response to potent volatile anesthetic gases, such as halothane, sevoflurane, desflurane, the depolarizing muscle relaxant succinylcholine, and, rarely in humans, to stresses, such as vigorous exercise and heat. The syndrome is likely to be fatal if untreated. Early recognition of the signs of MH provides the clinical diagnostic clues. Diagnostic testing relies on assessing the in vitro contracture response of biopsied muscle to halothane, caffeine, and other drugs. Dantrolene sodium is a specific antagonist of the pathophysiologic changes of MH and should be available wherever general anesthesia is administered. The prevention and treatment of acute episodes of this disorder is of paramount importance to the oral and maxillofacial surgeon. The management of such patients in the oral and maxillofacial surgery setting and the recent advances in the field of MH are presented.     

222 base pairs in NS5B region and the determination of hepatitis C virus genotype 6

OBJECTIVE: The present study was performed to genotype hepatitis C virus (HCV) by direct sequencing of a 222-bp nucleotide in the NS5B region and comparing the results with those of direct sequencing in the core region. We investigated a new region for HCV genotyping which gave the best performance to discriminate HCV genotype 6a, the unique genotype found in Southeast Asia. METHODS: Plasma samples taken from 57 HCV-infected blood donors were used in this study. RT-PCR products were amplified using primers located in the NS5B region. The 222-bp PCR products were purified and sequenced. The genotype of HCV isolates were obtained by phylogenetic analysis and compared with HCV reference strains stored in the GenBank database. The HCV sequences clustering in the same node were considered to be of the same genotype. RESULTS: Thirty-one, 22 and 4 samples of HCV genotype 3a, 1a and 1b, respectively, were analyzed by this method. Upon comparison with genotyping in the core region, 86 and 14% of the samples yielded concordant and discordant genotype results, respectively. The majority of discordant results (63%; 5 of 8) was observed with HCV genotype 6a which yielded 6a upon core sequencing as opposed to 1a or 3a upon NS5B sequencing. CONCLUSION: HCV genotype 6a obtained by direct sequencing in the core region could not be unequivocally arrived at by sequencing 222 bp in the NS5B region. Hence, sequencing in the core region is preferable for genotyping our specimens, even though longer PCR products are required as this method enables discrimination between genotype 6a and the remaining genotypes.