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.     

Heterozygous nonsense mutation SATB2 associated with cleft palate, osteoporosis, and cognitive defects

Studies of human chromosomal aberrations and knockout (KO) mice have suggested SATB2 as a candidate gene for a human malformation syndrome of craniofacial patterning and brain development. Of 59 unrelated patients with craniofacial dysmorphism, with or without mental retardation, one 36-year-old man had a nonsynonymous mutation in SATB2. The affected individual exhibited craniofacial dysmorphisms including cleft palate, generalized osteoporosis, profound mental retardation, epilepsy and a jovial personality. He carries a de novo germline nonsense mutation (c.715C>T, p.R239X) in the exon 6 of SATB2. Expression studies showed that the mutant RNA was stable, expected to produce a truncated protein predicted to retain its dimerization domain and exert a dominant negative effect. This new syndrome is the first determined to result from mutation of a gene within the family that encodes nuclear matrix-attachment region (MAR) proteins.     

PDGFRa mutations in humans with isolated cleft palate

Isolated cleft palate (CP) is common in humans and has complex genetic etiologies. Many genes have been found to contribute to CP, but the full spectrum of genes remains unknown. PCR-sequencing of the entire coding regions and the 3′ untranslated region (UTR) of the platelet-derived growth factor receptor alpha (PDGFRa) and the microRNA (miR), miR-140 identified seven novel single base-pair substitutions in the PDGFRa in 9/102 patients with CP (8.8%), compared with 5/500 ethnic-matched unaffected controls (1%) (the two-tailed P-value<0.0001). Of these seven, four were missense mutations in the coding regions and three in the 3′UTR. Frequencies of four changes (three in coding, one in 3′UTR) were statistically different from those of controls (P-value<0.05). The c.*34G>A was identified in 1/102 cases and 0/500 controls. This position is conserved in primates and located 10 bp away from a predicted binding site for the miR-140. Luciferase assay revealed that, in the presence of miR-140, the c.*34G>A significantly repressed luciferase activity compared with that of the wild type, suggesting functional significance of this variant. This is the first study providing evidence supporting a role of PDGFRa in human CP.     

Prevalence of Mycoplasma and Chlamydia pneumonia in severe community-acquired pneumonia among hospitalized children in Thailand

Pneumonia is the leading cause of pediatric morbidity and mortality worldwide, and Mycoplasma pneumoniae and Chlamydia pneumoniae are the two most common atypical pathogens. This study was designed to determine the prevalence and clinical impact of mycoplasma and chlamydia pneumonia in children hospitalized with severe pneumonia. Children 1 month-15 years old with a diagnosis of severe pneumonia (WHO criteria) were recruited between March 2005 and March 2006. Serologic studies were performed for anti-M. pneumoniae and anti-C. pneumoniae IgG/M on admission and 2-4 weeks afterward using ELISA. Of 52 patients, 13 (25%) were positive for Mycoplasma, 8 (15%) were positive for Chlamydia, 4 (7.6%) were positive for a mixed infection and 27 (52%) were negative. The subjects' mean age was 23.8+/-4.1 months. The mean of initial oxygen saturation on admission was 87.5+/-1.2%. Fever and prolonged cough were the leading symptoms. The mean of hospitalization was 18.8+/-2.6 days, chlamydia pneumonia had the longest duration, 30+/-10.2 days and 13/52 (25%) study subjects developed respiratory failure. Only 10% were treated with adequate antibiotic prior to serologic results. There was one mortality (1/52, 2%). Our study suggests that mycoplasma and chlamydia infections are commonly found among children hospitalized with severe pneumonia. Coverage with an appropriate antibiotic should be considered to hasten recovery.     

Cost-utility analysis of treatments for stage IB cervical cancer

Objective

To analyze the cost-utility of two common clinical practices for stage IB cervical cancer patients from provider and societal viewpoints.

Methods

A decision tree model was conducted to examine value for expenditure between the following: (1) radical hysterectomy with pelvic lymph node dissection (RHPLND) with or without postoperative adjuvant therapy according to the risk of recurrence and (2) concurrent chemoradiotherapy (CCRT). The relevant studies were identified to extract the probability data, and meta-analysis was performed. Direct medical costs were estimated from hospital database and medical records review. Direct non-medical costs and utility parameters were obtained through interviews with patients to estimate quality-adjusted life years (QALYs) outcome. The time horizon was according to the life expectancy of Thai women.

Results

From provider viewpoint, RHPLND and CCRT resulted in approximate costs of US $5,281 and US $5,218, respectively. The corresponding costs from societal viewpoint were US $6,533 and US $6,335, respectively. QALYs were 16.40 years for RHPLND and 15.94 years for CCRT. The estimated incremental cost effectiveness ratio of RHPLND in comparison to CCRT from provider and societal viewpoints were US $100/QALY and US $430/QALY, respectively. RHPLND had more cost-effectiveness than CCRT if patients did not need adjuvant therapy. The most effective parameter in model was a direct medical cost of CCRT. At the current ceiling ratio in Thailand, RHPLND provides better value for money than CCRT, with a probability of 75%.

Conclusion

RHPLND is an efficient treatment for stage IB cervical cancer. This advantage is only for patients who require no adjuvant treatment.     

Revision of the Thai Red Cross intradermal rabies post-exposure regimen by eliminating the 90-day booster injection

The Thai Red Cross intradermal post-exposure rabies prophylaxis regimen (TRC-ID) is being used in Thailand, the Philippines, Sri Lanka and is making inroads in India. It consists of two injections of 0.1 mL of any World Health Organization recommended tissue culture rabies vaccine intradermally at two sites on days 0, 3, 7, followed by one injection on days 28 and 90. Two decades of experience had shown that approximately 11% of 187,000 possibly rabies exposed subjects who received the TRC-ID schedule, did not return for the 90-day booster. No rabies deaths had, however, been reported from this group. This stimulated two studies to determine whether the 90-day booster can be abolished. They demonstrated that, if the single 28-day 0.1 mL injection is increased to two at two sites, a comparable antibody response can be achieved and the 90-day booster can be omitted. The tissue culture rabies vaccine used in the preliminary study was purified chick embryo vaccine (PCEC Chiron) and for this study it was chromatography purified Vero cell vaccine (CPRV, Aventis-Pasteur). CPRV had been previously shown to be as immunogenic and effective as purified Vero cell rabies vaccine (PVRV).     

Process and outcome measures of expert/novice performance on a haptic virtual reality system

Objectives

The goal of dental education is to guide students’ development through different stages from novice to competent, eventually resulting in an expert clinician. In this study we sought to identify process and outcome measures of clinical skill performance by comparing novices and experts using a virtual reality (VR) simulation system developed by our group.

Methods

Ten novices (fourth-year dental students), and ten experts in prosthodontics performed a crown preparation task with a haptic VR that provided force feedback to the operating tool while interacting with the virtual tissue/organ. For each step of the crown preparation, the system automatically recorded data associated with performance process including time to task completion (T), force used (F), and angulations (A) of the bur. The preparation outcome (O) scores were graded by an expert in the field. An independent t-test was conducted on all dependent variables (F in x-, y-, z-axes; A in zy, zx, xy planes; T and O) between experts and novices.

Results

Experts performed significantly better than novices (p < 0.05) as shown by greater O. Expert T was significantly less than that of novices (p < 0.05). Instrument A as well as F used were significantly different in almost all preparation steps in both groups (p < 0.05).

Conclusion

This study clearly demonstrated the ability of outcome and process measures to distinguish between novice and expert performance in crown preparation using a haptic VR system.     

Epidermal nevus syndrome

Epidermal nevus syndrome is a group of congenital neurocutaneous disorders characterized by epidermal nevi in association with cerebral, ocular, skeletal, and sometimes cardiac and renal abnormalities. These nevi have been classified according to their predominant component. We described a child presenting with inflammatory linear verrucous epidermal nevus on the head, which is an uncommon location. He also encountered ocular and central nervous system structural disorders.     

Thai elderly who do not coreside with their children

In this paper, data from a nationally representative survey of elderly Thais living in private households are analyzed. The analysis focuses on situations of the 756 elderly who do not coreside with an adult child. Only a minority of those elderly who do not coreside with an adult child were childless. The majority have at least one noncoresident child with whom they could potentially live. Daily contact with children for elderly who live alone was not significantly different from that of elderly who live with their children, suggesting that households that are classified as being separate may in fact function as single households or that at least one non-coresident child may live in very close proximity to the elderly person. Differences between urban and rural elderly in terms of type of support received from non-coresident children as well as likelihood of living near a non-coresident child are discussed.