PubMed · 7870211
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E A Holyoke. 1994. Three physician explorers.. https://pubmed.ncbi.nlm.nih.gov/7870211/
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A solid-phase microextraction (SPME) procedure has been developed to successfully extract eighteen chlorine-containing pesticides from water. A fused-silica fiber coated with a non-polar polydimethylsiloxane stationary phase was used to extract the analytes from water samples over a concentration range of 0.001 to 100 ng/ml. Limits of detection at a ng/l level were achieved with GC and flame ionization detection, and improved to sub ng/l levels using GC-MS, or GC with electron-capture detection (ECD). The reproducibility of the measurements between fibers was found to be very good, with precision typically below 20% R.S.D. within a single fiber. Qualitative analysis was performed on river and lake samples from Southern Ontario. Samples from the Arctic region of Canada were analyzed quantitatively using a dual ECD system.
HLA-B27 is present throughout Eurasia but is virtually absent among the genetically unmixed native populations of South America, Australia, and among equatorial and southern African Bantus and Sans (Bushmen). It has a very high prevalence among the native peoples of the circumpolar arctic and subarctic regions of Eurasia and North America, and in some regions of Melanesia. Results of recent epidemiologic studies of spondyloarthropathies in populations with a relatively high prevalence of B27 are also reviewed.