Previous research updated the mortality experience of North American synthetic rubber industry workers during the period 1944-1998, determined if leukemia and other cancers were associated with several employment factors and carried out Poisson regression analysis to examine exposure-response associations between estimated exposure to 1,3-butadiene (BD) or other chemicals and cancer. The present study used Cox regression procedures to examine further the exposure-response relationship between several unlagged and lagged, continuous, time-dependent BD exposure indices (BD parts per million (ppm)-years, the total number of exposures to BD concentrations >100 ppm ("peaks") and average intensity of BD) and leukemia, lymphoid neoplasms and myeloid neoplasms. All three BD exposure indices were associated positively with leukemia. Using continuous, untransformed BD ppm-years the regression coefficient (beta) from an analysis that controlled only for age was 2.9 x 10(-4) (p
1,3-Butadiene has been assessed as a Priority Substance under the Canadian Environmental Protection Act. The general population in Canada is exposed to 1,3-butadiene primarily through ambient air. Inhaled 1,3-butadiene is carcinogenic in both mice and rats, inducing tumors at multiple sites at all concentrations tested in all identified studies. In addition, 1,3-butadiene is genotoxic in both somatic and germ cells of rodents. It also induces adverse effects in the reproductive organs of female mice at relatively low concentrations. The greater sensitivity in mice than in rats to induction of these effects by 1,3-butadiene is likely related to species differences in metabolism to active epoxide metabolites. Exposure to 1,3-butadiene in the occupational environment has been associated with the induction of leukemia; there is also some limited evidence that 1,3-butadiene is genotoxic in exposed workers. Therefore, in view of the weight of evidence of available epidemiological and toxicological data, 1,3-butadiene is considered highly likely to be carcinogenic, and likely to be genotoxic, in humans. Estimates of the potency of butadiene to induce cancer have been derived on the basis of both epidemiological investigation and bioassays in mice and rats. Potencies to induce ovarian effects have been estimated on the basis of studies in mice. Uncertainties have been delineated, and, while there are clear species differences in metabolism, estimates of potency to induce effects are considered justifiably conservative in view of the likely variability in metabolism across the population related to genetic polymorphism for enzymes for the critical metabolic pathway.
Delay in discharge of psychiatric patients frequently is attributed to the lack of available community resources, or to the unwillingness of the patient or his family to accept discharge or transfer to another facility. The role of the psychiatric system itself rarely is mentioned as a factor. A study of 138 psychiatric patients in a Canadian community hospital in 1978 showed that 35 per cent were judged to be delayed in their discharge. By far the greatest source of delay was the administration of the various psychiatric services within the system. Delayed patients were found to be statistically similar to nondelayed patients, except for the delayed patients tendency to be poorer and to be overrepresented on two of the six wards studied. The cost implications of the delays in discharge are discussed, as are suggestions for solving the problems within the administrative framework.
Calcium urolithiasis is often associated with increased intestinal absorption and urine excretion of calcium, and has been suggested to result from increased vitamin D production. The role of the enzyme 1 alpha-hydroxylase, the rate-limiting step in active vitamin D production, was evaluated in 36 families, including 28 sibships with at least a pair of affected sibs, using qualitative and quantitative trait linkage analyses. Sibs with a verified calcium urolithiasis passage (n = 117) had higher 24-h calciuria (P = 0.03), oxaluria (P = 0.02), fasting and postcalcium loading urine calcium/creatinine (Ca/cr) ratios (P = 0.008 and P = 0.002, respectively), and serum 1,25(OH)2 vitamin D levels (P = 0.02) compared with nonstone-forming sibs (n = 120). Markers from a 9-centiMorgan interval encompassing the VDD1 locus on chromosome 12q13-14 (putative 1 alpha-hydroxylase) were analyzed in 28 sibships (146 sib pairs) of single and recurrent stone formers and in 14 sibships (65 sib pairs) with recurrent-only (> or = 3 episodes) stone-forming sibs. Two-point and multipoint analyses did not reveal excess in alleles shared among affected sibs at the VDD1 locus. Linkage of stone formation to the VDD1 locus could be excluded, respectively, with a lambda d of 2.0 (single and recurrent stone formers) and 3.25 (recurrent stone formers). Quantitative trait analyses revealed no evidence for linkage to 24-h calciuria and oxaluria, serum 1,25(OH)2 vitamin D levels, and Ca/cr ratios. This study shows absence of linkage of the putative 1 alpha-hydroxylase locus to calcium stone formation or to quantitative traits associated with idiopathic hypercalciuria. In addition, there is coaggregation of calciuric and oxaluric phenotypes with stone formation.
The Canadian Forces' (CF) deployable hospital, 1 Canadian Field Hospital, was deployed to Haiti after an earthquake that caused massive devastation. Two surgical teams performed 167 operations over a 39-day period starting 17 days after the index event. Most operations were unrelated to the earthquake. Replacing or supplementing the destroyed local surgical capacity for a brief period after a disaster can be a valuable contribution to relief efforts. For future humanitarian operations/disaster response missions, the CF will study the feasibility of accelerating the deployment of surgical capabilities.
The 1st Annual Awards for Action on HIV/AIDS and Human Rights were awarded to the Vancouver Area Network of Drug Users and to Dr. Wan Yanhai, a Chinese physician and activist. The international attention and media coverage of the awards was heightened by the fact that the Chinese government had detained Dr. Wan for disclosing information about unsanitary blood collection practices in Henan province. An international outcry led to Dr. Wan's release on 20 September 2002.
To evaluate the costs, consequences, effectiveness, and safety of ciprofloxacin vs standard antibiotic care in patients with an initial acute exacerbation of chronic bronchitis (AECB) as well as recurrent AECBs over a 1-year period.
A total of 240 patients, 18 years or older with chronic bronchitis, with a history of frequent exacerbations (three or more in the past year) presenting with a type 1 or 2 AECB (two or more of increased dyspnea, increased sputum volume, or sputum purulence).
The assessment included AECB symptoms, antibiotics prescribed, concomitant medications, adverse events, hospitalizations, emergency department visits, outpatient resources such as diagnostic tests, procedures, and patient and caregiver out-of-pocket expenses. Patients completed the Nottingham Health Profile, St. George's Respiratory Questionnaire, and the Health Utilities Index. The parameters were recorded with each AECB and at regular quarterly intervals for 1 year. These variables were compared between the ciprofloxacin-treated group and the usual-care-treated group.
Patients receiving ciprofloxacin experienced a median of two AECBs per patient compared to a median of three AECBs per patient receiving usual care. The mean annualized total number of AECB-symptom days was 42.9+/-2.8 in the ciprofloxacin arm compared to 45.6+/-3.0 days in the usual-care arm (p=0.50). The overall duration of the average AECB was 15.2+/-0.6 days for the ciprofloxacin arm compared to 16.3+/-0.6 days for the usual-care arm. Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care (relative risk=1.20; 95% confidence interval [CI], 0.91 to 1.58; p=0.19). Treatment assignment did not affect the interexacerbation period but a history of severe bronchitis, prolonged chronic bronchitis, and an increased number of AECBs in the past year were associated with shorter exacerbations-free periods. There was a slight, but not statistically significant, improvement in all quality of life measures with ciprofloxacin over usual care. The only factors predictive of hospitalization were duration of chronic bronchitis (odds ratio=4.6; 95% CI, 1.6, 13.0) and severity of chronic bronchitis (odds ratio=4.3; 95% CI, 0.8, 24.6). The incremental cost difference of $578 Canadian in favor of usual care was not significant (95% CI, -$778, $1,932). The cost for the ciprofloxacin arm over the usual care arm was $18,588 Canadian per quality-adjusted life year gained. When the simple base case analysis was expanded to examine the effect of risk stratification, the presence of moderate or severe bronchitis and at least four AECBs in the previous year changed the economic and clinical analysis to one favorable to ciprofloxacin with the ciprofloxacin-treated group having a better clinical outcome at lower cost ("win-win" scenario).
Treatment with ciprofloxacin tended to accelerate the resolution of all AECBs compared to usual care; however, the difference was not statistically significant. Further, usual care was found to be more reflective of best available care rather than usual first-line agents such as amoxicillin, tetracycline, or trimethoprim-sulfamethoxazole as originally expected. Despite the similar antimicrobial activities and broad-spectrum coverage of both ciprofloxacin and usual care, the trends in clinical outcomes and all quality of life measurements favor ciprofloxacin. In patients suffering from an AECB with a history of moderate to severe chronic bronchitis and at least four AECBs in the previous year, ciprofloxacin treatment offered substantial clinical and economic benefits. In these patients, ciprofloxacin may be the preferred first antimicrobial choice.