Validation of urinary thiocyanate as a biomarker of tobacco smoking.

Thiocyanate ion (SCN) is the major detoxication product of cyanide, which is converted to SCN by a thiosulphate sulphurtransferase, mainly in hepatic mitochondria. Low-level cyanide exposure for man is caused by factors such as dietary intake of cyanogenic glucosides, tobacco smoking, drug administration and occupational exposure to organic nitriles. Urinary SCN concentration was determined through a commercial kit for the analysis of cyanide in water. Spot urine samples were collected at 7:30 h and 12:30 h, from 99 healthy male white-collar office workers (non-smokers n=72, smokers n=27). Comparison of SCN excretion values did not show any difference between the morning and midday samples. The SCN median value of non-smokers was 24 µmol l(-1) (range 9-24 µmol l(-1)) and was statistically different from that of smokers (SCN = 92 µmol l(-1), range 33-275 µmol l(-1)) (p<0.001). In smokers median levels of SCN increased with the intensity of tobacco smoking and SCN individual excretion rose in relation to the number of cigarettes smoked daily (r=0.78, p<0.0001, n=16). In the whole group of investigated subjects SCN excretion was correlated with urinary cotinine, a well know biomarker of tobacco consumption (r=0.86, p<0.001, n=99). When the assay was applied as a smoking habit screening test, with a cut-off value of SCN=38 µmol l(-1) adopted to discriminate between non-smokers and smokers, the following smoker track-down predictive values resulted: 93% negative for non-smokers and 96% positive for smokers.

Concurrent ankle and subtalar joint arthrodesis.

The authors report on a new method for arthrodesing both the subtalar and ankle joints simultaneously. The technique uses a cannulated screw driven from the plantar aspect of the calcaneus and directed proximally through the subtalar and ankle joints. An inverted strut graft further supports and reinforces the ankle component anteriorly. Although one patient fractured the calcaneal-talar-tibial screw at 13 months postoperative, overall results of the five cases evaluated were excellent. Patient follow-up ranged from four to 54 months, with an average of 26 months.