Peak plasma interleukin-6 and other peripheral markers of inflammation in the first week of ischaemic stroke correlate with brain infarct volume, stroke severity and long-term outcome

BACKGROUND: Cerebral ischaemia initiates an inflammatory response in the brain and periphery. We assessed the relationship between peak values of plasma interleukin-6 (IL-6) in the first week after ischaemic stroke, with measures of stroke severity and outcome. METHODS: Thirty-seven patients with ischaemic stroke were prospectively recruited. Plasma IL-6, and other markers of peripheral inflammation, were measured at pre-determined timepoints in the first week after stroke onset. Primary analyses were the association between peak plasma IL-6 concentration with both modified Rankin score (mRS) at 3 months and computed tomography (CT) brain infarct volume. RESULTS: Peak plasma IL-6 concentration correlated significantly (p < 0.001) with CT brain infarct volume (r = 0.75) and mRS at 3 months (r = 0.72). It correlated similarly with clinical outcome at 12 months or stroke severity. Strong associations were also noted between either peak plasma C-reactive protein (CRP) concentration or white blood cell (WBC) count, and all outcome measures. CONCLUSIONS: These data provide evidence that the magnitude of the peripheral inflammatory response is related to the severity of acute ischaemic stroke, and clinical outcome

Forced, not voluntary, exercise effectively induces neuroprotection in stroke

Previous treadmill exercise studies showing neuroprotective effects have raised questions as to whether exercise or the stress related to it may be key etiologic factors. In this study, we examined different exercise regimens (forced and voluntary exercise) and compared them with the effect of stress-only on stroke protection. Adult male Sprague-Dawley rats (n = 65) were randomly assigned to treatment groups for 3 weeks. These groups included control, treadmill exercise, voluntary running wheel exercise, restraint, and electric shock. Levels of the stress hormone, corticosterone, were measured in the different groups using ELISA. Animals from each group were then subjected to stroke induced by a 2-h middle cerebral artery (MCA) occlusion followed by 48-h reperfusion. Infarct volume was determined in each group, while changes in gene expression of stress-induced heat shock proteins (Hsp) 27 and 70 were compared using real-time PCR between voluntary and treadmill exercise groups. The level of corticosterone was significantly higher in both stress (P < 0.05) and treadmill exercise (P < 0.05) groups, but not in the voluntary exercise group. Infarct volume was significantly reduced (P < 0.01) following stroke in rats exercised on a treadmill. However, the amelioration of damage was not duplicated in voluntary exercise, even though running distance in the voluntary exercise group was significantly (P < 0.01) longer than that of the forced exercise group (4,828 vs. 900 m). Furthermore, rats in the electric shock group displayed a significantly increased (P < 0.01) infarct volume. Expression of both Hsp 27 and Hsp 70 mRNA was significantly increased (P < 0.01) in the treadmill exercise group as compared with that in the voluntary exercise group. These results suggest that exercise with a stressful component, rather than either voluntary exercise or stress alone, is better able to reduce infarct volume. This exercise-induced neuroprotection may be attributable to up-regulation of stress-induced heat shock proteins 27 and 70

Admission blood glucose and short term survival in primary intracerebral haemorrhage: a population based study

Background: The role of admission blood glucose level on the prognosis of patients with intracerebral haemorrhage has not been elucidated. Objective: To examine this association on the basis of an epidemiologically representative patient material. Methods: 249 500 people living in the catchment area of the Central Hospital of Central Finland. The diagnosis of ICH was established if verified by cranial computed tomography (CT) or autopsy. Results: Of the 416 patients who fulfilled the diagnostic criteria, 30 died before admission and 386 were admitted to the Central Hospital. All 329 patients (290 nondiabetics and 39 diabetics) with both admission blood glucose and cranial CT data were included in the study. The mean blood glucose level was 10.6 mmol/l for nondiabetics who died on the day of onset, 8.6 mmol/l for those dying during days 1 to 28, and 6.8 mmol/l for the 28 day survivors. The corresponding figures for diabetics were 13.9 mmol/l, 12.5 mmol/l, and 9.3 mmol/l. In both nondiabetics and diabetics, patients who died had significantly higher mean glucose than the 28 day survivors (p<0.0001 versus p = 0.029). However, blood glucose of the surviving diabetics was as high as that of the deceased nondiabetics (9.3 mmol/l versus 9.1 mmol/l). In nondiabetics, admission blood glucose was associated with parameters signifying severe stroke; disturbed consciousness, large haematoma volume and shift of cerebral midline structures, and high admission mean arterial pressure. In logistic regression analysis, high admission blood glucose in nondiabetics was a significant predictor of death during the first 28 days of onset (odds ratio 1.22, 95% CI 1.07 to 1.40). Conclusions: High admission blood glucose predicts increased 28 day case fatality rate in both nondiabetic and diabetic patients with ICH. Because high admission blood glucose was associated with markers of severe stroke, we are inclined to support the stress theory; high admission blood glucose is the result of a serious ICH

Long term survival after primary intracerebral haemorrhage: a retrospective population based study

Objectives: To determine the long term survival and predictors of death in patients with primary intracerebral haemorrhage (ICH) in Central Finland. Methods: Data were collected retrospectively on all adult patients with first ever ICH in Central Finland county between September 1985 and December 1991. The survival of all patients at the end of December 2002 was investigated. Kaplan–Meier survival curves were constructed and factors associated with both early (⩽28 days) and late deaths determined. Long term survival was compared with the general Finnish population of the same age and sex distribution. The causes of death were compared with those of the population of Central Finland. Results: 411 patients with first ever ICH were identified, 199 men (mean age 64.9 years) and 212 women (mean age 69.5); 30 died before hospital admission, and 208 (50.6%) within the first 28 days. In Kaplan–Meier analysis, at 16 years the cumulative survival was 3.2% for men and 9.8% for women. The 28 day survivors had a 4.5-fold increased annual risk of dying during the first year after ICH, and 2.2-fold during years 2 to 6. On admission, significant independent predictors of death within the first four weeks were unconsciousness, lateral shift of cerebral midline structures, mean arterial pressure ⩾134 mm Hg, hyperglycaemia, anticoagulant treatment, and ventricular extrasystoles. Predictors of late death for the 28 day survivors were old age, male sex, and heart failure. Conclusions: Primary intracerebral haemorrhage has a poor short and long term outcome. The results emphasise the importance of primary and secondary prevention for ICH

Graphene field-effect transistors as THz detectors:Distinguishing between resistive self-mixing and the hot-carrier thermoelectric effect

Graphene-based detectors of THz radiation - despite their improvement over the years - continue to exhibit a lower sensitivity than detectors made from other material systems. In order to gain a deeper understanding of some of the detection processes and their constraints, we analyze here experimentally and by simulations the operation of graphene TeraFETs, detectors based on rectification in antenna-coupled field effect transistors, over the frequency range 0.1-1.2 THz. The devices were fabricated with an advanced wafer-scale process technology. It is well-known that two detection mechanisms contribute, resistive self-mixing and the photothermoelectric effect. We determine the respective contributions to the responsivity and their frequency dependencies, put the results into perspective with competing technologies, and suggest ways to improve detector performance.</p