Results of multiyear international interlaboratory comparison program for mercury in human hair.

Since 1990, Laboratory Services, First Nations and Inuit Health Branch (Health Canada) conducted an interlaboratory comparison program for mercury in human hair. Laboratory Services initiated this program to compare the performance of participating laboratories, analyzing mercury in human hair samples by a variety of analytical methods and instrumental detection techniques. The results of the quality assurance program, which included 31 participants on four continents, are described. Of the participating laboratories, 92% consistently meet QA/QC performance limits for the determination of Hg in human hair. A variety of analytical methods using different digestion and instrumental techniques gave similar results. The most frequently used instrumental techniques were: CV-AA, CV-AFS, and ICP-MS. A summary of results from 24 rounds is provided. The feedback from this program has assisted some laboratories in improving their results and solving some of their analytical problems.

The design, synthesis and transmembrane transport studies of a biomimetic sterol-based ion channel.

A model sterol-based ion channel was rationally designed and synthesized. The potential ion channel is comprised of a tartrate-derived crown ether to which six steroids are appended. Macromolecule 1a was incorporated into phospholipid vesicles and shown to facilitate the transmembrane transport of sodium and lithium ions using alkali metal NMR spectroscopy.

Congener specific analysis of toxaphene in serum using ECNI-MS.

A method for the determination of environmentally relevant toxaphene congeners (eg chlorinated bornanes (CHBs)) in serum is described. Four chlorinated bornane congeners are predominant in serum.

Development of a method for the analysis of PCB congeners and organochlorine pesticides in blood/serum.

A method for the determination of environmentally relevant PCB congeners and organochlorine pesticides in human blood/serum is described. The method is validated through recovery experiments with standards and reproducibility of quality control samples.

Congener specific analysis of polychlorinated biphenyls (PCBs) in serum using GC/MSD.

A new congener specific method has been developed for extraction and quantitative determination of PCB contaminants of serum. After liquid-liquid extraction and chromatographic fractionation with Carbopack-C/florisil column, the analytes were identified and quantified utilizing gas chromatography/mass spectrometry (GC/MSD) using selected ion monitoring (SIM) technique. Recoveries of 35 non-planar PCB congeners (#18, 28, 31, 44, 49, 52, 60, 66, 74, 82, 87, 99, 101, 105, 110, 114, 118, 128, 138, 141, 146, 151, 153, 156, 157, 158, 167, 170, 171, 180, 183, 185, 187, 189 and 194) and 5 non-ortho (coplanar) congeners (#37, 77, 81, 126 and 169) from spiked serum were between 55-115%.

A comparison of rotational representations in structure and motion estimation for manoeuvring objects.

Alternative methods are examined for estimating motion and structure of objects undergoing smooth maneuvers through measurements of feature positions in long, multiple-camera image sequences. Performance of extended Kalman filters are compared for Euler angle-axis, roll-pitch-yaw, and quaternion parameterizations of rotational motion. The angle-axis method was found to give the best overall performance with a computationally efficient implementation.

Outcome after perforation sustained during pneumatic dilatation for achalasia.

Although esophageal perforation complicates about 5% of pneumatic dilatations performed for achalasia, little is known about associated hospital and long-term courses. In order to assess the outcome of such patients undergoing emergency surgery for repair, records of seven patients sustaining perforation during pneumatic dilatation were compared to those of five patients undergoing elective myotomy during the same period. In perforation patients, mean intervals following the procedure were 3.6 hr to administration of antibiotics and 9.6 hr to surgery. The perforation and elective myotomy groups had similar mean durations of operation (3.8 vs 3.3 hr), intensive care stays (2 vs 1 days) and hospitalization (12 vs 11 days); perforation patients had a significantly longer mean interval from surgery to oral intake (7 vs 5 days). Postdischarge long-term outcomes were alike in the groups. It is concluded that patients with perforation from pneumatic dilatation that is recognized and treated promptly have outcomes that are comparable to those of patients who undergo elective myotomy.

Studies on some derivatives of oxamniquine.

On the basis of the remarkable biological similarities between hycanthone and oxamniquine and as a sequel to our finding that some esters of hycanthone are active against hycanthone-resistant schistosomes, we prepared oxamniquine acetate, oxamniquine N-methylcarbamate, and four substituted phenylsulfonohydrazones of oxamniquine aldehyde. These compounds were tested for their effect on survival of and on [3H]uridine incorporation into hycanthone-sensitive and -resistant Schistosoma mansoni. All of these derivatives were effective to a greater or lesser degree in killing worms and in inhibiting [3H]uridine incorporation in the sensitive strain, but none was effective in the resistant strain.