Buffered Lugol's Iodine Preserves DNA Fragment Lengths.

Museum collections play a pivotal role in the advancement of biological science by preserving phenotypic and genotypic history and variation. Recently, contrast-enhanced X-ray computed tomography (CT) has aided these advances by allowing improved visualization of internal soft tissues. However, vouchered specimens could be at risk if staining techniques are destructive. For instance, the pH of unbuffered Lugol's iodine (I2KI) may be low enough to damage deoxyribonucleic acid (DNA). The extent of this risk is unknown due to a lack of rigorous evaluation of DNA quality between control and experimental samples. Here, we used formalin-fixed mice to document DNA concentrations and fragment lengths in nonstained, ethanol-preserved controls and 3 iodine-based staining preparations: (1) 1.25% weight-by-volume (wt/vol.) alcoholic iodine (I2E); (2) 3.75% wt/vol. I2KI; and (3) 3.75% wt/vol. buffered I2KI. We tested a null hypothesis of no significant difference in DNA concentrations and fragment lengths between control and treatment samples. We found that DNA concentration decreases because of staining-potentially an effect of measuring intact double-stranded DNA only. Fragment lengths, however, were significantly higher for buffered I2KI and control samples, which were not, themselves, significantly different. Our results implicate buffered I2KI as the appropriate choice for contrast-enhanced CT imaging of museum wet collections to safely maximize their potential for understanding genetic and phenotypic diversity.

Las colecciones de museos juegan un papel crucial en el avance de la ciencia biológica al preservar la historia y la variación fenotípica y genotípica. Recientemente, la tomografía computarizada (CT) mejorada con contraste ha facilitado estos avances al permitir una mejor visualización de los tejidos blandos internos. Sin embargo, los especímenes con vales podrían estar en riesgo si las técnicas de tinción son destructivas. Por ejemplo, el pH del yodo de Lugol sin tamponar (I2KI) puede ser lo suficientemente bajo como para dañar el ADN. Se desconoce el alcance de este riesgo debido a la falta de una evaluación rigurosa de la calidad del ADN entre las muestras de control y las experimentales. Aquí utilizamos ratones fijados en formalina para documentar las concentraciones de ADN y las longitudes de los fragmentos en controles no teñidos, preservados en etanol, y en tres preparaciones de tinción basadas en yodo: (i) 1.25% peso/volumen (wt/vol.) de yodo alcohólico (I2E), (ii) 3.75% wt/vol. I2KI, y (iii) 3.75% wt/vol. I2KI tamponado. Probamos una hipótesis nula de que no hay diferencias significativas en las concentraciones de ADN y las longitudes de los fragmentos entre las muestras de control y las de tratamiento. Encontramos que la concentración de ADN disminuye debido a la tinción, potencialmente un efecto de medir solo ADN de doble cadena intacto. Sin embargo, las longitudes de los fragmentos fueron significativamente mayores para I2KI tamponado y las muestras de control, que no fueron, ellas mismas, significativamente diferentes. Nuestros resultados implican que I2KI tamponado es la opción adecuada para la imagenología CT mejorada con contraste de colecciones húmedas de museos para maximizar de manera segura su potencial para comprender la diversidad genética y fenotípica.

Effectiveness of a statewide child abuse and neglect educational program for dental professionals.

The purpose of this study was to evaluate the effect of a statewide child abuse and neglect (CAN) educational program. Questionnaires were mailed to a random sample of 2,500 dentists and 2,500 hygienists registered in Massachusetts. Approximately half the responding dentists and hygienists were aware of the existence of the program either via a theme issue of The Journal of the Massachusetts Dental Society or presentations at the Yankee Dental Congresses. Most respondents indicated that the program had increased their awareness and knowledge of CAN and made them more likely to detect and report such cases. However 38.1% of the respondents were not comfortable calling the Department of Social Services (DSS). The major reason cited for not reporting was the lack of an adequate history to confirm suspicions. Approximately one-fifth of the dentists and hygienists reported having seen dental pathology or injuries to children that they suspected to be a result of child abuse or neglect, while 13.6% admitted to seeing at least one suspicious case in the past 12 months. One-third of the respondents stated that they thought at least one of these suspicious cases was definitely the result of abuse. Only a minority of these dentists and hygienists reported to the DSS any of the suspicious cases they'd seen; however, the majority of these reporters were satisfied with the results of their reports.