Characterization of deoxyribonucleic acid (DNA) obtained from teeth subjected to various environmental conditions.

This study was designed to determine the effects of various environmental factors on the deoxyribonucleic acid (DNA) obtained from dental pulp. Extracted teeth were subjected to the following conditions: varying pH (3,7,10); temperature (4 degrees C, 25 degrees C, 37 degrees C, incineration); humidity (20%, 66%, 98%); various types of soil (sand, potting soil, garden soil); seawater; burying the teeth outdoors, and aging (one week to six months). In addition, teeth that had been extracted and held at room temperature for 16 and 19 years were also examined. Following isolation of DNA, the samples were analyzed on yield gels to determine the concentration and integrity of the recovered DNA. Restriction digestion with Pst I was followed by electrophoresis of the generated fragments, Southern transfer to nylon membranes, and hybridization to both human and bacterial probes. It was determined that, aside from soil, the environmental conditions examined did not affect the ability to obtain high-molecular-weight human DNA from dental pulp. Restriction fragment length polymorphic (RFLP) analysis of selected samples was performed. Dental pulp patterns were compared with bloodstain exemplars, revealing matching patterns, although an increase in band-shifting was observed with extended exposure to elevated temperatures.     

Effective handling of health-related leaves of absence

This article will address the legal obligations of employers in non-union settings toward employees who request pregnancy leave, parental or medical leave, workers' compensation leave, and other forms of disability leave. Specifically, this article will address the legal standards set forth under the Pregnancy Discrimination Act, various state pregnancy and family leave acts, workers' compensation retaliatory discharge authority, and the Americans With Disabilities Act of 1990. In addition, this article will provide practical guidance for employers in formulating effective leave policies that provide the maximum amount of operational flexibility while at the same time minimizing the risk of costly and excessive litigation.