Mechanism of anomalously increased oil displacement with aqueous viscoelastic polymer solutions.

Single-phase flows of viscoelastic polymer solutions in both microfluidic devices and rock cores exhibit apparent flow thickening. We demonstrate that this thickening occurs above a critical Deborah number corresponding to the onset of spatio-temporal fluctuations. These fluctuations are observed to occur over a broad range of spatial and temporal scales consistent with elastic turbulence. The fluctuations provide a previously unreported mechanism for enhancing the displacement of a second, capillary trapped, immiscible phase.

Carotid sinus syndrome is common in very elderly patients undergoing tilt table testing and carotid sinus massage because of syncope or unexplained falls.

BACKGROUND AND AIMS: Although the incidence of falls and syncope increase with age, the underlying mechanisms are not fully understood, particularly in very old patients. We report diagnostic outcomes of tilt table and carotid sinus massage (TT/CSM) testing in a population of older old subjects (82% over 80 years of age) referred for TT/CSM from a falls clinic for assessment of syncope or unexplained falls. METHODS: Prospective observational study between January 1, 2001 and January 1, 2005 involving 290 consecutive subjects undergoing TT/CSM testing according to European Society of Cardiology guidelines for the diagnosis and management of syncope. RESULTS: Combination of TT/CSM provided a positive result in 62% of subjects, and was significantly more likely to be positive in subjects over the age of 80 (68% vs 50%, p=0.001). Carotid sinus syndrome (CSS) was the most common diagnosis, and was significantly more common in subjects over 80 (48% vs 34%, p=0.022) particularly due to a higher incidence of mixed CSS (16% vs 7%, p=0.023). There was no significant difference in the diagnosis of subjects referred due to falls and those reporting syncope (p=0.93). No cardiovascular or neurological adverse events occurred. CONCLUSIONS: In our cohort of very elderly patients, the diagnostic accuracy of tilt testing and carotid sinus massage was high and adverse incidents absent when testing was indicated by a geriatrician experienced in the assessment of falls and syncope. We advocate the use of TT/CSM testing as part of a comprehensive falls/syncope assessment for the diagnostic evaluation of older patients presenting with unexplained falls and/or syncope in whom structured assessment has not identified a cause for their symptoms.

Does inflammation predispose to recurrent vascular events after recent transient ischaemic attack and minor stroke? The North West of England transient ischaemic attack and minor stroke (NORTHSTAR) study.

BACKGROUND AND HYPOTHESIS: Inflammation is implicated in the pathogenesis and outcome of ischaemic injury. Poststroke inflammation is associated with outcome but it remains unclear whether such inflammation precedes or results from ischaemic injury. We hypothesised that inflammatory markers are associated with an increased risk of recurrent vascular events soon after transient ischaemic attack and minor stroke. METHODS: This was a multicentre, prospective, nested case-control study. Plasma concentrations of C-reactive protein, interleukin-6, interleukin-1-receptor antagonist and fibrinogen, leucocyte counts, erythrocyte sedimentation rate and inflammatory gene allele frequencies were analysed in 711 patients with recent transient ischaemic attack or minor stroke. Cases were defined by the incidence of one or more recurrent vascular events during the three-month follow-up. Association of inflammatory markers with case-status was determined using conditional logistic regression. RESULTS: Plasma concentrations of C-reactive protein, interleukin-1-receptor antagonist and interleukin-6 were not associated with case-status. In secondary analyses, only erythrocyte sedimentation rate was significantly associated with case-status (odds ratio 1·39, 95% confidence interval 1·03-1·85; P=0·03), but this effect did not persist after adjustment for smoking and past history of transient ischaemic attack or stroke. Single nucleotide polymorphisms in four inflammatory genes (interleukin-6, fibrinogen, P-selectin and vascular cell adhesion molecule-1) were nominally associated with case-status. CONCLUSIONS: Circulating inflammatory markers were not associated with recurrent vascular events. Nominally significant associations between genetic markers and case-status will require replication. These data provide little evidence for an inflammatory state predisposing to stroke and other vascular events in a susceptible population.

A difficult case of inflammatory myositis.

A 79-year-old lady presented with subclinical autoimmune hypothyroidism and proximal muscle weakness, which failed to respond to thyroxine. Subsequent electromyography and muscle biopsy confirmed polymyositis, which responded well to immunosuppressive therapy. She presented 4 months later with a thyroid carcinoma, most likely anaplastic, and died shortly afterwards. Although the association between malignancy and polymyositis remains controversial, to our knowledge this is the first report of thyroid carcinoma occuring in association with polymyositis and autoimmune hypothyroidism.