The effects of water filtration systems on fluoride: Washington, D.C. metropolitan area

According to the U.S. Environmental Protection Agency (EPA), approximately one in eight Americans is exposed to potentially harmful microbes, pesticides, lead, or radioactive radon whenever they drink a glass of tap water or take a shower. One reason for this exposure is that the water plants are aging or ill equipped to process the huge amounts of raw sewage and agricultural pollutants that are still being discharged into our drinking-water sources. Other compounds such as fluoride and chloride have been added to the community water supplies for health benefits. Water filtration systems are becoming more popular as people become concerned with pollutants in the public water supply and questions are being raised as to whether fluoride is affected by these filters. The aim of this pilot study was to assess the efficacy of three types of water filtration systems and to determine their impact on fluoride content of the water in the Washington, D.C. metropolitan area. One sample of water was collected daily for fourteen days, from one location. The sample was divided to use as a control and the test samples which were processed through various filter systems. With the use of a fluoride ion specific electrode, the fluoride concentration level was tested in all samples in order to determine the percentage of fluoride removed. This study was intended to prove that the water filtration systems did not affect the advantage offered by optimum water fluoride levels. The experimental samples were ascertained and compared to the control group, resulting in three of the four carbon filters showing statistically significant amounts of fluoride removed from the water. Both Reverse Osmosis and Distillation, as expected, removed the fluoride at a high rate.     

Mixed lymphocyte reactions do not predict severity of graft versus host disease (GVHD) in HLA-DR compatible, sibling bone marrow transplants.

Mixed lymphocyte reactions (MLRs) were measured in 25 HLA-A, B and DR compatible sibling bone marrow transplants. Only four of 25 MLRs were positive and in these the low reactivity was of doubtful clinical importance. There was no correlation between MLR and the subsequent development or severity of graft versus host disease (GVHD). A survey of bone marrow transplant units in the United Kingdom showed that most centres perform HLA-DR typing as well as an assessment of the MLR. Factors other than histocompatibility are important in the pathogenesis of GVHD and the data from this study suggest that conventional MLRs can be omitted in HLA-A, B and DR compatible sibling bone marrow transplants.     

Used leucodepletion filters as a source of large quantities of DNA suitable for the study of genetic variations in human populations

A simple technique for developing large control panels with large quantities of DNA suitable for studies in population genetics was established. BACKGROUND AND OBJECTIVES: Both a lack of suitable controls and insufficient quantities of DNA for repeated analysis of the same control group often hamper the investigation of genetic markers for disease. MATERIALS AND METHODS: Using a waste product from routine blood donation, we describe a simple method that allows the investigator to extract large amounts of DNA. RESULTS: A mean of 1520 microg of DNA per sample was obtained. The DNA obtained remains suitable for polymerase chain reaction and sequencing techniques after 2 years of storage at both 4 degrees C and -40 degrees C. CONCLUSION: This technique allows the development of a large panel of controls with sufficient quantities of genomic DNA for thousands of tests.