Thrombolysis for acute stroke in patients with pre-existing disability
![Figure](https://www.cmaj.ca/content/cmaj/169/3/185/F1.medium.gif)
Figure. Photo by: Vincenzo Pietropaolo
Most studies that have investigated the effects of intravenous thrombolysis in acute stroke have excluded patients with pre-existing disability. Blaine Taylor Foell and colleagues carried out a prospective study to compare the 3-month outcomes of patients with pre-existing disability and those without, after they had all received intravenous thrombolytics for acute stroke. They also compared their results with those obtained in the National Institute of Neurological Disorders and Stroke (NINDS) trial. They found that patients with pre-existing disability had a higher mortality rate (33% v. 14%) and greater functional disability, as measured by a modified Rankin scale, than patients without a pre-existing disability. Although there appeared to be no difference between the 2 groups in neurologic scores for those who survived, the benefits of thrombolysis appear to be uncertain for patients with a pre-existing disability.
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Back belts to prevent occupational low-back pain
![Figure](https://www.cmaj.ca/content/cmaj/169/3/185/F2.medium.gif)
Figure. Photo by: Art Explosion
The Canadian Task Force on Preventive Health Care has issued a statement regarding the use of mechanical back supports (e.g., belts or corsets) as a preventive measure for occupational low-back pain. After reviewing the evidence from 5 randomized controlled trials, the Task Force deems that there is insufficient evidence to warrant the widespread use of such lumbar supports. However, in its summary of the evidence, it does identify a subset of individuals with a previous history of low-back pain for whom the short-term use of back belts may have some benefit.
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Insights into DEET
![Figure](https://www.cmaj.ca/content/cmaj/169/3/185/F3.medium.gif)
Figure. Photo by: Art Explosion
Given the mounting concern about West Nile virus infection this summer, this article provides useful information about the DEET-based insect repellents that are commonly used by Canadians. Gideon Koren and colleagues review the pharmacology and toxicology of DEET, particularly with regard to whether it may be used safely by children and pregnant and lactating women. The authors point out that serum DEET concentrations following topical application are considerably lower than those associated with toxic effects after oral ingestion. They conclude that DEET is a relatively safe chemical when used as recommended.
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Risk factors for group B streptococcal disease in neonates
Although group B streptococcus (GBS) is still a major cause of neonatal mortality and morbidity, its incidence appears to have declined since the implementation of preventive guidelines in 1994. Risk factors identified at that time included preterm delivery, a previous infant with GBS infection, GBS bacteriuria, intrapartum fever and premature rupture of the membranes (> 18 hours before delivery). Carol Elaine Adair and colleagues reviewed 90 cases of neonatal GBS and found that intrauterine monitoring is an additional independent risk factor for GBS infection.
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