Risk factors and treatment of stroke at the time of recurrence

The profile of recurrent ischemic strokes has not been much investigated. The aim of this study was to evaluate how the therapeutic strategies recommended for secondary prevention after an ischemic stroke are implemented in the real world of clinical practice. All patients admitted for a recurrent ischemic stroke or TIA were prospectively registered. The etiology was determined according to the TOAST classification. The risk factors and cardiovascular treatment at the time of the recurrence were recorded. A total of 168 patients were evaluated. Most of the patients (61%) recurred after 1 year. The recurrent stroke was not associated with a particular etiological subtype. The most frequent risk factor was hypertension (79%), followed by hypercholesterolemia (43%), smoking (25%), and diabetes (22%). Most of the patients had more than 1 risk factor (84%). Hypertension was not satisfactorily controlled in 38% of patients, hypercholesterolemia in 42%, and diabetes in 59%. A significant minority of patients (15%) were not taking any antithrombotic agent despite a history of stroke or TIA. Only 34% of the cases with a known atrial fibrillation were on anticoagulant therapy and the International Normalized Ratio was < 2.0 in 71% of them. In conclusion, stroke prevention needs to be improved by better implementation of therapeutic strategies in clinical practice. The patients should also be better informed about target values as well as the importance of physical activity and smoking cessation.     

The haemodynamic, renal excretory and hormonal changes induced by resting in the left lateral position in normal pregnant women during late gestation

Objective  To characterise the haemodynamic, renal-electrolyte and hormonal parameters in normal near-term pregnancy.
Design  Observational prospective case-series study.
Setting and population  Eleven women with normal pregnancies at 35–39 weeks gestation.
Methods  Following baseline laboratory assessments and placement of a right-atrial catheter, serial measurements were obtained for 2 hours in the supine position (SP) followed by a change to the (LLP) and subsequent observations for 2 hours.
Main outcome measures  Blood pressure (BP), central venous pressure (CVP), atrial natriuretic peptide (ANP), plasma renin activity (PRA), plasma aldosterone (ALDO), diuresis, creatinine clearance, sodium and potassium excretion.
Results  In the SP, the subjects' BP remained stable while their CVP decreased. In the LLP, the subjects' systolic and diastolic BP consistently decreased by about 15 mmHg and their CVP increased within the first 60 minutes. ANP levels doubled in the subjects while they rested in the LLP, whereas the subjects' PRA and ALDO levels decreased by half compared with when they rested in the SP. In the LLP, the subjects' creatinine clearance significantly increased by 12% and their sodium excretion and diuresis increased by 38% and 59% respectively.
Conclusion  Rest in the LLP induces systemic and intra-renal haemodynamic and hormonal changes that may play a central physiological role in the renal excretory response to restore excessive sodium/water retention in late pregnancy.     

Hemisphere specialisation and inter-hemispheric cooperation during a phonological task: Effect of lexicality as assessed by the divided visual field approach

In the presented experiment we explored the effect of lexicality on hemisphere specialisation and cooperation during a phonological task. The divided visual field (DVF) method with bilateral presentation (BVF) of redundant (identical) stimuli is considered an appropriate approach to assess inter-hemispheric cooperation (IHC). IHC is supposed to increase the efficiency of cognitive processes. Specifically, it has been shown that, compared to unilateral hemifield presentation, word processing is significantly more efficient if stimuli were presented under bilateral redundancy conditions. The performance enhancement during bilateral vs. unilateral presentation is called bilateral redundant gain (BRG). In the present experiment a DVF was used and participants were required to perform a rhyme detection task in two blocks, one in words and another one in pseudowords. Each item was presented in two different modes, one unilateral (right or left hemi-visual field) and another one bilateral (simultaneous redundant presentation). Unilateral trials allow one to study hemispheric specialisation, while bilateral redundant trials allow one to study inter-hemispheric cooperation. We obtained left hemisphere specialisation for both types of items (word, pseudoword). Moreover, words were more efficiently processed than pseudowords. Additionally, words were processed more efficiently in BVF than in unilateral presentation, inducing BRG. No similar effect was obtained for pseudowords. These results are discussed in respect to findings reported by other studies suggesting that hemispheric specialisation depends on lexicality. Moreover, compared to lexical decision tasks used in previous studies, the phonological task used in the present study seems to modulate the inter-hemispheric cooperation less.     

Bone marrow donor registries: the relation between registry size and probability of finding complete and partial matches [see comments]

In a registry of volunteer bone marrow donors, the relation between registry size and probability of finding an exact or partial match for a random recipient cannot be theoretically derived because it depends on specifics of the human leukocyte antigen (HLA) haplotype frequencies in the donor and recipient populations. The relation must be explicitly calculated using empirically determined HLA haplotype frequency data for all possible pairings between a donor and a recipient population. This report describes a general solution to this problem. The method shows that the relation of the probability of matching to registry size is sigmoidal, with small increases in probability at the extremes of registry size and a middle range of registry size within which the probability of matching increases most sharply. This range determines the approximate size of the most cost-effective registry. In addition, for any pairing of donor and recipient populations, there is a maximum probability of identifying a match of a given quality for a random recipient, which cannot be exceeded even if registry size were infinite. This upper limit is a function of the frequency of blank (or unknown) alleles in the donor and recipient populations; the higher that frequency, the lower the maximum probability of achieving any given quality of match. The determinants of the probability of achieving a given quality of match with a given registry size are (1) the genetic heterogeneity within the recipient and donor populations, which increases the registry size required to achieve a given probability of matching, and (2) the degree of genetic homology between the donor and recipient populations, which increases the maximum probability of matching and also lowers registry size requirements. The method described here can be used to estimate donor pool size requirements using any donor and recipient populations for which HLA frequency data are available.