Classification and natural history of clinically identifiable subtypes of cerebral infarction

Singular Integral Equations. By N.I. Muskhelishvili. Translated fromthe 2nd Russian edition by J.R.M. Radok. Pp. 447. F1. 28.50. 1953. (Noordhoff, Groningen)

Background and Purpose Stroke occurring with atrial fibrillation (AF) is more likely to be fatal or more severe than non-AF stroke based on clinical series, but data from prospective epidemiological studies are sparse and inconsistent Methods Over 40-year follow-up of the original 5070 Framingham cohort, 501 initial ischemic strokes, including 103 with AF, were analyzed Stroke severity was rated as none, mild, moderate, severe, or fatal Since 1981, functional status indicated by the Barthel index has been evaluated acutely and at 3, 6, and 12 months Severity and functional status of AF strokes were compared with non-AF strokes using χ2 test and Student's t test Thirty-day mortality was assessed by logistic regression analyses Results AF was associated with increased stroke severity (P=048) Thirty-day mortality was greater in AF strokes than in non-AF strokes (25% versus 14%) The multivariate-adjusted odds ratio for 30-day mortality for AF subjects was 184 (95% confidence interval, 104 to 327)

Stroke Severity in Atrial Fibrillation The Framingham Study

Surface texturing has emerged in the last decade as a viable option of surface engineering resulting in significant improvement in load capacity, wear resistance, friction coefficient etc. of tribological mechanical components. Various techniques can be employed for surface texturing but Laser Surface Texturing (LST) is probably the most advanced so far. LST produces a very large number of micro-dimples on the surface and each of these micro-dimples can serve either as a micro-hydrodynamic bearing in cases of full or mixed lubrication, a micro-reservoir for lubricant in cases of starved lubrication conditions, or a micro-trap for wear debris in either lubricated or dry sliding. The present paper reviews the current effort being made world wide on surface texturing in general and on laser surface texturing in particular. It presents the state of the art in LST and the potential of this technology in various lubricated applications like mechanical seals, piston rings and thrust bearings. The paper also describes some fundamental on going research around the world with LST.

State of the art in Laser Surface Texturing

Background During the last three decades, new management strategies have been developed for patients with aneurysmal subarachnoid hemorrhage. To assess whether the case-fatality rate has improved after the introduction of new management strategies, we studied outcome in all population-based studies from 1960 onward. Summary of Review To identify population-based studies that reported on case-fatality rate in subarachnoid hemorrhage, we performed a MEDLINE search and checked all reference lists of the studies found. Two authors (J.W.H. and G.J.E.R.) independently assessed all studies for eligibility, using predefined criteria for case finding and diagnosis, and extracted data on case-fatality rates. We used weighted linear regression analysis to quantify change in case-fatality rate over time. We found 21 studies, describing 25 study periods between 1960 and 1992. Case-fatality rates varied between 32% and 67%, with the exception of one recent study. The case-fatality rate decreased by 0.5% per year (95% c...

Case-Fatality Rates and Functional Outcome After Subarachnoid Hemorrhage A Systematic Review

A Theory of Lubrication by Microirregularities

A prognostic score was derived from a prospective study of 148 consecutively admitted patients, aged less than 76 years, who survived the first 24 hours after an acute stroke. Multivariate analysis was used to compare the presenting clinical features of 137 (93%) of these patients with their outcome after two months. Little change in the level of residual disability was detected in 128 of these patients after a further four months. The features which were found to predict functional dependence or death included older age, complete limb paralysis, depression of conscious level and the combination of hemiplegia and hemianopia with higher cerebral dysfunction. Hemiparesis uncomplicated by hemianopia or higher cerebral dysfunction predicted a return to functional independence. A discriminant function derived from this analysis can be used to calculate the likelihood of recovery to independent function for an individual patient following an acute stroke.

https://jnnp.bmj.com/content/jnnp/47/5/475.full.pdf

Predicting the outcome of acute stroke: a prognostic score.

To assist physicians without easy access to CT scanning facilities, a scoring system was devised to aid the clinical diagnosis of acute stroke. A consecutive series of 192 patients under 76 years was studied prospectively from admission. The clinical features of 174 (91 per cent) of these patients were compared with their subsequent CT scan or autopsy diagnosis. The scoring system derived from this analysis determines the relative likelihood of infarction or haemorrhage from quantitative assessment of eight clinical variables. Clinical diagnosis with this method was more accurate than the diagnosis made by the patients' physicians. Lumbar puncture performed in 72 patients added little to the accuracy of diagnosis. Nine patients were found to have mass lesions, of whom only one presented with a clear history. Convulsions and neurological deficits which were prolonged or discontinuous in evolution occurred more frequently in patients with mass lesions than in those with vascular lesions.

Clinical diagnosis of the acute stroke syndrome.

Load Support and Leakage from Microasperity-Lubricated Face Seals

We tested the Guy's Hospital stroke diagnostic score using the clinical data from two independent samples of patients with acute stroke. These were 228 patients from the Oxfordshire community stroke project and 130 referred to the National Hospital for Nervous Diseases in London. The diagnosis was confirmed by computed tomography or necropsy in each case. The optimum cut off point on the clinical score for the differentiation of intracranial haemorrhage from infarction was found to be the same for both the patients in our study and those from whose data the score was derived originally. Set at this level, the score achieved a sensitivity for the diagnosis of haemorrhage of 81% and 88% in the patients from Oxford and London, respectively. In those from Oxford infarction was diagnosed with a sensitivity of 78% with an overall predictive accuracy of 78% with an overall London the sensitivity for infarction was also 78% with an overall predictive accuracy of 82%. When it is essential to exclude intracerebral blood before starting treatment in the small proportion of patients with stroke who require anticoagulation the Guy's Hospital score is not sufficiently accurate to replace computed tomography. The score is, however, the most accurate clinical means of differentiating haemorrhage from infarction as the cause of stroke. It is suggested that it should be used as a screening test in epidemiological studies and in large scale trials of low risk treatment for the secondary prevention of stroke when computed tomography in all cases is impracticable.

https://www.bmj.com/content/bmj/291/6510/1675.full.pdf

Christine Allen

Papers

A Theory of Lubrication by Microirregularities

Predicting the outcome of acute stroke: a prognostic score.

Clinical diagnosis of the acute stroke syndrome.

Load Support and Leakage from Microasperity-Lubricated Face Seals

Clinical diagnosis of intracranial haemorrhage using Guy's Hospital score.