Dental Erosion Risk Factors in 6 to 12 Year Old children in Mexico City.

Objective: To assess the prevalence and dental erosion risk factors in Mexican schoolchildren. Study design: A transversal and analytical study was conducted on 411 children aged 6 to 12 years old in a public primary school of Mexico City. The children's parents answered a standardized questionnaire about their risk factors, and the Smith and Knight index was applied to assess their dental erosion degree. Results: The prevalence of dental erosion was 62%. The odds ratio and X2 tests revealed that probiotic beverage consumption (OR 1.658; CI 95%: 1.106-2.485; p = 0.014), sports beverages (OR: 2.807; CI 95%: 1.129-6.983; p = 0.021), natural juices (OR: 3.344; CI 95%: 1.556-7.184; p = 0.003), fruits and snacks with hot peppers and lemon (OR: 1.594; CI 95%: 1.066-2.382; p = 0.023), and syrups (OR: 1.869; CI 95%: 1.060-3.296; p = 0.029) were all risk factors for dental erosion. Conclusions: This study indicated that a high existence of dental erosion, which mainly affects the primary molars, is related to the frequent consumption of beverages and foods with acidic pH levels.

Pneumonectomy in isoflurane-anesthetized rats without tracheal intubation: an experimental model.

INTRODUCTION: A few models for pneumonectomy in rats have been described, and in most of these, anesthesia includes orotracheal intubation, which increases morbidity and mortality and also adds technical complexity. Models without tracheal intubation but with injectable anesthesia are difficult to reproduce, however, and lead to a lengthy postoperative-recovery period with high morbidity and mortality rates. OBJECTIVE: The objective of this study was to describe a simple, safe, and effective experimental model for pneumonectomy in rats without tracheal intubation. MATERIALS AND METHODS: A left-sided pneumonectomy was performed on 26 Sprague-Dawley rats anesthetized by isoflurane applied via a mask without tracheal intubation. To avoid dangerous traction movements, the lung pedicle was ligated en bloc using clips. RESULTS AND DISCUSSION: No rat demonstrated cardiorespiratory depression. Of the 26 rats, 1 was dehydrated and had lost more than 10% of its body weight, resulting in death on the third day after surgery. Total mortality was therefore 3.8%. Mean (standard deviation [SD]) anesthesia duration was 9.8 (1.0) minutes, surgery time was 3.0 (0.6) minutes, and open pneumothorax time was 1.2 (0.3) minutes. Mean (SD) weight loss during the early postoperative period was 4.5% (3.5%). These results were more satisfactory than results obtained using ketamine mixtures as anesthetic agents (ketamine plus xylacine, and ketamine plus diazepam). CONCLUSION: Our model for left-sided pneumonectomy in isoflurane-anesthetized rats does not require endotracheal intubation and is effective, safe, quick, and easily reproducible.

Loss of a reporter gene for green fluorescent protein during tumor progression suggests the recruitment of host cells in rats with experimentally induced colon cancer.

The interactions between a host's normal cells and tumor cells appear to be of significant importance during the development of tumors. In the present study, we examined this issue using a cancer model in vivo in which tumor cells were tagged with a reporter gene for green fluorescent protein (GFP). We used a model of colon cancer in immunocompetent rats, which were given a subcutaneous injection of tumor cells that had been transfected with a gene for GFP. We found that the number of fluorescent cells decreased with the progression of the primary tumors and that lymph node and lung metastases were never macroscopically fluorescent. No GFP-encoding sequences were detected by PCR in many of the long-term primary tumors, in most lymph node metastases (86%) and in all lung metastases, whereas the detection of mutated k-ras, which identified such cells as tumor cells, was always positive. To explain these findings, we present a brief review of the literature and postulate that tumor growth did not occur exclusively as a result of the division of the injected cells, but also involved recruitment of host cells.