Roger Weir

Association of Physical Activity Level and Stroke Outcomes in Men and Women: A Meta-Analysis

OBJECTIVE The protective effect of physical activity (PA) on risk of stroke remains controversial as a result of lack of insight into the sources of heterogeneity between studies. We performed a comprehensive meta-analysis of studies to (1) quantify the association between PA level and risk of stroke outcomes and (2) test the hypothesis that the association of PA level with stroke outcomes will be similar between men and women. The outcome measures are stroke incidence, stroke mortality, or both. METHODS Cohort studies were identified by searching MEDLINE and EMBASE (from 1986 to 2005) and meta-analysis conducted according to meta-analysis of Observational Studies in Epidemiology (MOOSE) group recommendations. Data were reported as pooled relative risk (RR) and 95% confidence intervals (CI) using random-effects models to assess the association of stroke outcomes with PA level. Heterogeneity was investigated, and sensitivity analysis was performed. Stratified analysis by gender was performed. RESULTS Of 992 articles, 13 satisfied all eligibility criteria and were studied. Compared with low PA, moderate PA caused an 11% reduction in risk of stroke outcome (RR = 0.89, 95% CI 0.86-0.93, p < 0.01) and high PA a 19% reduction (RR = 0.81, CI 0.77-0.84, p < 0.01). Among the men, results showed a 12% reduction in risk associated with moderate PA (RR = 0.88, CI 0.82-0.94, p < 0.01) and 19% reduction for high PA (RR = 0.81, CI 0.75-0.87, p < 0.01). Among the women, results showed a 24% reduction in risk for high PA (RR = 0.76, CI 0.64-.89, p < 0.01). There was, however, no significant risk reduction associated with a moderate PA level in women. CONCLUSIONS Increased PA level appears beneficial in reduction of risk of stroke and related outcomes. However, higher levels of PA may be required in women to achieve as significant a risk reduction as in men. An exercise regimen tailored to women to improve related physiological mechanisms will likely be beneficial.

Inhibition of N6-[3H]Cyclohexyladenosine Binding by Carbamazepine

Summary: The mechanism of action of carbamazepine (CBZ) (Tegretol), despite widespread use in the management of partial and tonic‐clonic seizures in adults, is not completely understood‐ In animals, adenosine and adenosine analogues have anticonvulsant effects that may be due to interactions with central A, adenosine receptors. CBZ (at therapeutically relevant concentrations) inhibits the binding of agonists and antagonists to brain A1 adenosine receptors, but whether as an agonist/antagonist is not clear. The adenosine agonist, N6‐[3H]cyclohexyladenosine ([3H]CHA), binds to membranes from rat cortex and hippocampus at two nanomolar binding sites or states. To clarify the actions of carbamazepine at the A, adenosine receptor, its inhibitory actions were compared with those of known adenosine agonists and xanthine antagonists using 0.1 nM[3H]CHA, in which almost all binding is to the higher affinity state, or 10 nM [3H]CHA, in which there is a substantial contribution of binding from both states. The ratios of the IC50 values (concentration that inhibits specific binding by 50%) at 10 nM [3H]CHA to the IC50 values at 0.1 nM [3H]CHA were 18–31 for the agonists and 4–10 for the xanthine antagonists. CBZ had a ratio of 3. The inhibitory effects of GTP on [3H]CHA binding were less in the presence of the adenosine agonist, 2‐chloroadenosine than were inhibitory effects in the presence of the xanthine antagonist theophylline or CBZ in both cortex and hippocampus. These in vitro studies indicate that CBZ is an antagonist at A, adenosine receptors in cerebral cortical and hippocampal membranes from rat brain. Agonist activity at A1 adenosine receptors would have been compatible with the sedative anticonvulsant effects of CBZ, but these data do not support a role of the anticonvulsant action of carbamazepine on A1 adenosine receptors in cerebral cortex or hippocampus.

Rare association of thymoma, myasthenia gravis and sarcoidosis : a case report

IntroductionThe association of thymoma with myasthenia gravis (MG) is well known. Thymoma with sarcoidosis however, is very rare. We presented an interesting case with coexisting thymoma, MG and sarcoidosis.Case presentationA 59-year-old female patient with a history of sarcoidosis was admitted to the hospital with a one-day history of sudden onset of right-sided partial ptosis and diplopia. Neurosarcoidosis with cranial nerve involvement was considered, but was ruled out by the clinical findings, and MG was confirmed by the positive tensilon test, electrophysiological findings and positive acetylcholine receptor binding antibodies. On further evaluation, a CT chest scan showed a left anterior mediastinal mass and bilateral lymphadenopathy. Post surgical diagnosis confirmed the thymoma and sarcoidosis in the lymph nodes.ConclusionWhen two or more diseases of undetermined origin are found together, several interesting questions are raised. It is important to first confirm the diagnoses individually. Immunologic mechanisms triggering the occurrence of these diagnoses together, are difficult to address. Although the coexistence of thymoma, MG and sarcoidosis may be coincidental, it is noteworthy to report this case because of the multiple interesting features observed as well as the rarity of occurrence.

Artery of Percheron Infarction as an Unusual Cause of Korsakoff's Syndrome

The Korsakoff syndrome is defined as “an abnormal mental state in which memory and learning are affected out of all proportion to other cognitive functions in an otherwise alert and responsive patient.” Confabulation refers to false or erroneous memories arising, not deliberately, in the context of a neurological amnesia and is often thought of as pathognomonic of the Korsakoff syndrome. Although the exact pathophysiology is unknown, various studies have identified brain lesions in the thalami, mammillary bodies, and frontal cortex. We report a case of a 68-year-old male presenting with acute altered mental status on July 16, 2015. The neuropsychological dysfunctions included prominent Korsakoffs syndrome, which became apparent when the altered mental status resolved. Amnesia was accompanied by prominent confabulation, disorientation, and lack of insight into his own disability. Neuroradiological data indicated that the intralaminar and dorsomedial nuclei in bilateral thalami were infarcted by occlusion of the artery of Percheron. We believe that ours is one of few reported cases of Korsakoff syndrome in a patient with infarction involving the territory of the artery of Percheron. We conclude that bilateral thalamic lesions could cause Korsakoffs syndrome and the intralaminar and dorsomedial nuclei might be important structures in the pathogenesis of confabulation.