Multi Centricity of Oral Verrucous Carcinoma: A Case Series of 22 Cases.

Verrucous carcinoma (VC) is an uncommon variant of squamous cell carcinoma characterized by proliferative outgrowing clinical appearance of the tumor, Incidence of VC is 2-12 % among oral cancers, the true incidence of VC can be accessed only from surgically treated cases since thorough processing of the entire tumor is necessary for accurate diagnosis, foci of invasive squamous cell carcinoma are found often in the substance of these tumors, thus, over reporting of this tumor is not uncommon. The retrospective data of a tertiary cancer hospital was analysed to understand the clinical challenges and outcome of patients with VC. The frequent association of VC with second primary oral cancer (22.7 %) observed in our series highlights the multi centricity of carcinogenesis in these patients.

An association of external and internal enamel pearls.

We report a rare case of an association of external enamel pearl with internal enamel pearl on the root of a molar. To the best of our knowledge, association of external and internal enamel pearls has not been previously reported. We discussed the histogenesis of enamel pearls and proposed that internal enamel pearl formation may be a continuation of formation of external enamel pearl.

Determination of haloacetic acids in water by ion chromatography--method development.

The microextraction/ion chromatographic (IC) method developed in this study involves extraction of 9 haloacetic acids (HAAs) from aqueous samples (acidified with sulfuric acid to a pH of < 0.5 and amended with copper sulfate pentahydrate and sodium sulfate) with methyl tert-butyl ether (MTBE), back extraction into reagent water, and analysis by IC with conductivity detection. The separation column consists of an Ion Pac AG-11 (2 mm id x 50 mm length) guard column and an Ion Pac AS-11 (2 mm id x 250 mm length) analytical column, and the concentration column is a 4 mm id x 35 mm length Dionex TAC-LP column. Use of the 2 mm id Dionex AS-11 column improved detection limits especially for trichloracetic acid (TCAA), bromodichloroacetic acid (BDCAA), dibromochloroacetic acid (DBCAA), and tribromoacetic acid (TBAA). The peak interfering with BCAA elutes at the same retention time as nitrate; however, we have not confirmed the presence of nitrate. Stability studies indicate that HAAs are stable in water for at least 8 days when preserved with ammonium chloride at 100 mg/L and stored at 4 degrees C in the dark. At day 30, recoveries were still high (e.g., 92.1-106%) for dichloroacetic acid (DCAA), BCAA, dibromoacetic acid (DBAA), trichloroacetic acid (TCAA), BDCAA, and DBCAA. However, recoveries of monochloroacetic acid (MCAA), monobromoacetic acid (MBAA), and TBAA were only 54.6, 56.8, and 66.8%, respectively. Stability studies of HAAs in H2SO4-saturated MTBE indicate that all compounds except TBAA are stable for 48 h when stored at 4 degrees C in the dark. TBAA recoveries dropped to 47.1% after 6 h of storage and no TBAA was detected after 48 h of storage. The method described here is only preliminary and was tested in only one laboratory. Additional research is needed to improve method performance.

Automation of environmental ELISAs.

ELISAs for pesticides and herbicides in environmental and agricultural samples are becoming very important in screening applications [1-3]. Traditional chromatographic methods are expensive and results need long turnaround times, making them incompatible with rapid on-site decision making. ELISA methods have been shown to meet or exceed the performance of gas chromatography-they offer rapid low-cost analysis, thereby increasing the frequency of sampling and enhancing data quality. Automated ELISA workstations allow the full benefit of these kits to be realized. Sample preparation, reagent pipetting, incubation, and photometric evaluation can be performed without user intervention. Reliability is increased through the elimination of operator error, better accuracy and precision, and often higher speed. Much larger batch sizes are possible and these systems can provide sample tracking with report generation for documentation requirements. In this paper the manual procedures and ELISA methods are compared and some critical aspects of automating these ELISA kits are discussed.