Mechanisms of recurrence in subtypes of ischemic stroke: a hospital-based follow-up study

BACKGROUND: Information on the mechanism of recurrent stroke may help physicians treating patients with ischemic stroke. However, the mechanisms of recurrence in each stroke subtype are not well known, especially in Asians. OBJECTIVE: To compare the mechanisms of the index and recurrent stroke. DESIGN: Analysis of data from a prospective acute stroke registry. SETTING: University hospital. PATIENTS: Using the clinical syndrome, diffusion-weighted imaging, and vascular studies, we divided 901 patients into 5 groups: large-artery atherosclerosis, cardioembolism, small-artery disease, parent-artery disease occluding the deep perforators, and no determined cause. The patients with large-artery atherosclerosis were subdivided into 2 groups: intracranial and extracranial. MAIN OUTCOME MEASURES: The mechanisms of recurrent vascular events (strokes or coronary heart disease) in subtypes of ischemic stroke were compared. RESULTS: Ninety-three recurrent vascular events (86 strokes and 7 instances of coronary heart disease) were evaluated. The pattern of recurrent stroke differed for the intracranial and extracranial groups; unlike the patients with intracranial large-artery atherosclerosis, recurrent strokes in the extracranial group were often unpredictable with respect to the site of recurrence and degree of preexisting stenosis. None of the patients in the extracranial group had recurrences that were caused by intracranial large-artery atherosclerosis or vice versa. In patients with small-artery disease and stroke with no determined cause, intracranial stenosis was often found at the time of recurrence. CONCLUSIONS: From prognostic and therapeutic perspectives, patients with atherosclerosis should be divided into those with intracranial large-artery atherosclerosis and extracranial large-artery atherosclerosis. In addition, intracranial large-artery atherosclerosis may be important in the development of small-artery disease and stroke with no determined cause, especially in the population with a higher frequency of intracranial large-artery atherosclerosis.     

Plant-based immunocontraceptive control of wildlife--"potentials, limitations, and possums"

Possums (Trichosurus vulpecula), originally introduced from Australia, are spread over 90% of New Zealand and cause major economic and environmental damage. Immunocontraception has been suggested as a humane means to control them. Marsupial-specific reproductive antigens expressed at high levels in edible transgenic plant tissue might provide a safe, effective, and cheap oral delivery bait for immunocontraceptive control. As proof of concept, female possums vaccinated with immunocontraceptive antigens showed reduced fertility, and possums fed with potato-expressed heat labile toxin-B (LT-B) had mucosal and systemic immune responses to the antigen. This demonstrated that immunocontraception was effective in possums and that oral delivery in edible plant material might be possible. Nuclear transformation with reporter genes showed that transgenic carrot roots accumulate high levels of foreign protein in edible tissues, indicating their potential as a delivery vector. However, prior to attempts at large scale production, more effective immunocontraceptive antigen-adjuvant formulations are probably required before plant-based immunocontraception can become a major tool for immunocontraceptive control of overabundant vertebrate pests.     

Can we evaluate population screening strategies in UK general practice? A pilot randomised controlled trial comparing postal and opportunistic screening for genital chlamydial infection

STUDY OBJECTIVE: To assess whether opportunistic and postal screening strategies for Chlamydia trachomatis can be compared with usual care in a randomised trial in general practice. DESIGN: Feasibility study for a randomised controlled trial. SETTING: Three West of Scotland general medical practices: one rural, one urban/deprived, and one urban/affluent. PARTICIPANTS: 600 women aged 16-30 years, 200 from each of three participating practices selected at random from a sample of West of Scotland practices that had expressed interest in the study. The women could opt out of the study. Those who did not were randomly assigned to one of three groups: postal screening, opportunistic screening, or usual care. RESULTS: 38% (85 of 221) of the approached practices expressed interest in the study. Data were collected successfully from the three participating practices. There were considerable workload implications for staff. Altogether 124 of the 600 women opted out of the study. During the four month study period, 55% (81 of 146) of the control group attended their practice but none was offered screening. Some 59% (80 of 136) women in the opportunistic group attended their practice of whom 55% (44 of 80) were offered screening. Of those, 64% (28 of 44) accepted, representing 21% of the opportunistic group. Forty eight per cent (59 of 124) of the postal group returned samples. CONCLUSION: A randomised controlled trial comparing postal and opportunistic screening for chlamydial infection in general practice is feasible, although resource intensive. There may be problems with generalizing from screening trials in which patients may opt out from the offer of screening.