Genetics of ischemic stroke

Stroke is the third leading cause of death and a major cause of disability worldwide. Most cases of ischemic stroke are attributable to hypertension and other risk factors, but in over 20% of cases, the cause is unknown. Recent research has implicated some novel genes in the etiology of ischemic stroke, including genes for soluble epoxide hydrolase [sHE], 5-lipoxygenase activating protein [FLAP] and phosphodiesterase 4D [PDE4D]. Moreover, thrombophilic states such as prothrombin G20210A mutation and factor V Leiden are now known to cause arterial stroke as well as venous thrombosis. Meanwhile, the recent availability of enzyme replacement therapy for Fabry disease and the proven benefits of regular blood transfusion in certain patients with sickle cell disease have greatly altered the outlook of these devastating inherited disorders. Thus, our understanding of the role of genetic factors in stroke raises the prospects for accurate assessment of future stroke risk among susceptible individuals, in whom early preventive measures may be life-saving. Further research into the genetics of stroke will clearly compliment ongoing national and international efforts to reduce the global burden of stroke

Myasthenia gravis: presentation and outcome in 104 patients managed in a single institution

Few studies have attempted to delineate the clinical profile of myasthenia gravis [MG] among people of Arab ancestry. Therefore, we sought to clarify the clinical profile, the outcome of treatment and the role of thymectomy in non-thymomatous MG in Saudi Arabia. We retrospectively studied 104 patients followed over a mean period of 7.2 years [range, 1 to 22 years] at the King Khaled University Hospital, Riyadh, Saudi Arabia. Disease outcomes were compared among thymectomized and non-thymectomized patients according to the post-intervention status criteria of the Myasthenia Gravis Foundation of America [MGFA]. Age of onset was 22.5 +/- 9.3 years [mean +/- SD] in females and 28.2 +/- 15.9 years in males, with peaks in the second and third decades among females and the third and fourth decades among males. At diagnosis, a majority of patients had moderate generalized weakness, equivalent to MGFA class III severity. After medical treatment with or without thymectomy, 9.6% of all patients had achieved complete stable remission, 3.8% had pharmacological remission, 27.9% had minimal manifestations, 23.1% were improved, 20.2% were unchanged and 15.4% were worse. Only thymectomized patients without a thymoma achieved remission, a significant benefit over those who had no thymectomy [P=.02]. MG presents at a younger age among Saudi Arabs compared to other racial groups. Thymectomy conferred significant benefits towards achievement of remission

sympathetic skin response in diabetic neuropathy and its relationship to autonomic symptoms

To examine the utility of the sympathetic skin response [SSR] as a measure of impaired autonomic function among diabetic patients in Saudi Arabia. In this case-control study, baseline SSR was obtained from 18 healthy subjects, followed by nerve conduction studies, and SSR testing on a consecutive cohort of 50 diabetic patients with peripheral neuropathy. The SSR in diabetic patients was compared between those with autonomic neuropath] and those without autonomic neuropathy. This study was conducted at the King Khaled University Hospital, Riyadh, Saudi Arabia, from June 2006 to June 2007. The SSR was present in all healthy subjects and in 32 diabetic patients. Among 16 patients with autonomic neuropathy, the SSR was absent in 14 and present in 2, while 4 of 34 patients lacking evidence of autonomic neuropathy had absent SSR. Using Fishers' exact test, we found a strong association between absent SSR and autonomic neuropathy [p<0.001], however, not with age or duration of diabetes mellitus. As a diagnostic test of autonomic neuropathy, the SSR had a sensitivity of 87.5%, a specificity of 88.2%, a positive predictive value of 77.8%, and a negative predictive value of 93.7%. Absence of the SSR is a reliable indicator of autonomic neuropathy among patients with diabetes mellitus in Saudi Arabia

Association of plasma homocysteine and ischaemic stroke in a nigerian population

Epidemiologic evidence suggests that raised plasma homocysteine is an independent risk factor for ischaemic stroke. However, other studies found no association between plasma homocysteine and stroke. Our objective was to determine the relationship between plasma homocysteine concentrations and ischaemic stroke in the Nigerian population where there is no existing published data. Case-control study. University of Maiduyguri Teaching Hospital, Maidyguri, Nigeria. Fifty patients with ischaemic stroke and 50 control subjects, aged and sex-matched, were studied in relation to plasma homocysteine and other vascular risk factors. Comparison of mean plasma homocysteine between stroke cases and control subjects and Odds Ratios for stroke in patients with hyperhomocysteinemia. Mean plasma homocysteine was significantly higher in stroke cases than in control subjects [mean +/- SD: 20.8 +/- 10.2 micro mol/Lvs. 13.1 +/- 4.5 micro mol/L; P<0.001]. Other factors associated with ischaemic stroke were obesity, hypertension and elevated serum cholesterol. Using logistic regression analysis, there was an adjusted Odds Ratio of 1.9 [95% CI, 1.16-3.08] for ischaemic stroke for every 5 micro mol/L increase in plasma homocysteine concentrations. Raised plasma homocysteine was significantly associated with ischaemic stroke and treating hyperhomocysteinemia may be an effective way of decreasing the incidence of stroke

Activation of microglia in mice spinal cords following passive transfer of purified IgG from patients with amyotrophic lateral sclerosis

To determine whether IgG from amyotrophic lateral sclerosis [ALS] patients could cause activation of microglia, proliferation of astrocytes, and infiltration by lymphocytes within mice spinal cords. A group of 5 mice received injections of IgG purified from sera of patients with ALS. A control group of 5 mice received IgG from healthy humans, whilst a third group of 2 mice served as non-injected controls. One mouse served as a positive control and was injected with lipopolysaccharide, a known activator of microglia. Mice were culled after one week, for immunocytochemistry of spinal cord sections to localize the complement receptor CD11b on activated microglia, glial fibrillary acidic protein on astrocytes, and CD4 and CD8 receptors on lymphocytes. Histological examination was used to determine the presence of inflammatory reaction. This work was conducted at the Institute of Neurology, Queen Square London, United Kingdom, from January to July 2004. There was no significant difference in activation of microglia between mice injected with ALS IgG and mice injected with control IgG [p = 0.631], although mice injected with ALS IgG exhibited greater microglial activation than non-injected mice [p = 0.044]. Proliferation of astrocytes was not significantly different between the 3 groups. CD4 and CD8 lymphocytes were both absent in mice injected with ALS IgG, mice injected with control IgG and non-injected mice. Activation of microglia following passive transfer of IgG from ALS patients to mice represents a non-specific inflammatory response, rather than a primary mechanism for motor neuron degeneration