Homozygosity mapping of achromatopsia to chromosome 2 using DNA pooling

Achromatopsia is an autosomal recessive disease of the retina, characterized clinically by an inability to distinguish colors, impaired visual acuity, nystagmus and photophobia. A genome-wide search for linkage was performed using an inbred Jewish kindred from Iran. To facilitate the genome-wide search, we utilized a DNA pooling strategy which takes advantage of the likelihood that the disease in this inbred kindred is inherited by all affected individuals from a common founder. Equal molar amounts of DNA from all affected individuals were pooled and used as the PCR template for short tandem repeat polymorphic markers (STRPs). Pooled DNA from unaffected members of the kindred was used as a control. A reduction in the number of alleles in the affected versus control pool was observed at several loci. Upon genotyping of individual family members, significant linkage was established between the disease phenotype and markers localized on chromosome 2. The highest LOD score observed was 5.4 (theta = 0). When four additional small unrelated families were genotyped, the combined peak LOD score was 8.2. Analysis of recombinant chromosomes revealed that the disease gene lies within a 30 cM interval which spans the centromere. Additional fine-mapping studies identified a region of homozygosity in all affected individuals, narrowing the region to 14 cM. A candidate gene for achromatopsia was excluded from this disease interval by radiation hybrid mapping. Linkage of achromatopsia to chromosome 2 is an essential first step in the identification of the disease-causing gene.      

Effects of chronic treatment with methadone and naltrexone on sleep in addicts

Previous studies have described sleep disturbance secondary to chronic opiate use and abuse. Drug-dependency insomnia is of interest because chronic sleep disturbances can promote depressive symptoms which could lead to a drug relapse. For the first time we compared the polysomnographic parameters of 10 methadone-substituted outpatients and 10 naltrexone-treated outpatients. Methadone (-opioid agonist) produced a marked fragmentation of the sleep architecture with frequent awakenings and a decrease in EEG arousals. In comparison with methadone and controls, the naltrexone (-opioid antagonist) group showed the shortest sleep latency and the longest total sleep time. These data indicate that -agonists and -antagonists have different effects on sleep. The implications, especially the involvement of opioid-dopamine interactions on sleep and movements during sleep, are discussed.     

A laboratory comparison of the performance of the buddy lite™ and enFlow™ fluid warmers

Maintenance of normothermia is crucial to avoid patient morbidity. Newly released fluid warming devices have become smaller in size, but this change might impair efficacy. We performed an evaluation of the buddy lite? and enFlow? fluid warmers. We measured inflow and outlet temperatures of the devices at flow rates between 25 and 100 ml.min^?1 using saline at room temperature or cooled to 10 °C. At a flow rate of 25 ml.min^?1, the outlet temperature of the buddy lite was significantly higher than that of the enFlow (p < 0.0001), but at flow rates of 75 and 100 ml.min^?1, it was significantly lower (p < 0.0001). This pattern was the same for both room temperature and cooled saline. There was a significant drop in the temperature of saline along the length of a 1‐m outflow tube. We conclude that both devices provide effective fluid warming at a low flow rate, although the heating capability of the buddy lite is limited at high flow rates.