Marfan syndrome is not associated with intracranial aneurysms.

BACKGROUND AND PURPOSE: It has been proposed that patients with Marfan syndrome have an increased prevalence of intracranial aneurysms. This proposition is based on 10 clinical reports, 1 pathology case, and an autopsy series of 7 patients. By contrast, 5 clinical series of Marfan patients have failed to document any such relationship. We present our institution's autopsy and clinical experience with Marfan syndrome and analyze in our patient population the purported association between this condition and intracranial aneurysms. METHODS: The results of an autopsy series at the Johns Hopkins Hospital of 25 confirmed Marfan syndrome patients from 1939 to the present were reviewed retrospectively. The prevalence of intracranial aneurysms in this Marfan syndrome autopsy series was compared with that in the autopsy population at this institution and with that in the general autopsy population as reported in the literature. In addition, the prevalence of Marfan syndrome in a recent neurosurgical series of 710 consecutive aneurysm cases (1990-1998) was determined. RESULTS: Of the 25 autopsy cases, only 1 had evidence on autopsy of an unruptured, 2-mm aneurysmal dilatation at the anterior communicating artery complex. Three autopsy patients suffered intracranial hemorrhages but had negative angiography and postmortem examinations for intracranial aneurysms. The remaining 21 patients had negative autopsies for intracranial hemorrhages or intracranial aneurysms. The neurosurgical series of 710 patients treated for intracranial aneurysms did not include any patient with Marfan syndrome. CONCLUSIONS: The prevalence of 1 patient of 25 with an intracranial aneurysm is not statistically different from the 1.3% prevalence of intracranial aneurysms in the autopsy population at this institution (P=0.24) or from the 2.0% prevalence of intracranial aneurysms in the general autopsy population (P=0.31). We therefore conclude that there exists no evidence that Marfan syndrome is associated with an increased prevalence of intracranial aneurysms.     

Serotonin 2A receptor gene polymorphism is not associated with completed suicide.

Several lines of evidence indicate that a serotonergic dysfunction is involved in the biological susceptibility to suicide. Recently, the A-1438G polymorphism of the serotonin 2A (5-HT2A) receptor gene has been suggested to be associated with suicide, but the results are inconsistent. We examined whether the A-1438G polymorphism of the 5-HT2A receptor gene was associated with suicide itself using 151 Japanese completed suicides. No significant difference in genotype distribution or allele frequencies of the polymorphism was found between the completed suicides and the comparison group. We conclude that the A-1438G polymorphism of the 5-HT2A receptor gene is not likely to have a major effect on the biological susceptibility of suicide.     

Limb-girdle phenotype is frequent in patients with myopathy associated with GNE mutations

Mutations in NKX2-1 cause neurological, pulmonary, and thyroid hormone impairment. Recently, the disease was named brain-lung-thyroid syndrome. Here, we report three patients with brain-lung-thyroid syndrome. All patients were unable to walk until 24 months of age, and still have a staggering gait, without mental retardation. They have also had choreoathetosis since early infancy. Genetic analysis of NKX2-1 revealed a novel missense mutation (p.Val205Phe) in two patients who were cousins and their maternal families, and a novel 2.6-Mb deletion including NKX2-1 on chromosome 14 in the other patient. Congenital hypothyroidism was not detected on neonatal screening in the patient with the missense mutation, and frequent respiratory infections were observed in the patient with the deletion in NKX2-1. Oral levodopa did not improve the gait disturbance or involuntary movement. The results of (99m)Tc-ECD single-photon emission computed tomography (ECD-SPECT) analyzed using the easy Z-score imaging system showed decreased cerebral blood flow in the bilateral basal ganglia, especially in the caudate nuclei, in all three patients, but no brain magnetic resonance imaging (MRI) abnormalities. These brain nuclear image findings indicate that NKX2-1 haploinsufficiency causes dysfunction of the basal ganglia, especially the caudate nuclei, resulting in choreoathetosis and gait disturbance in this disease.     

Essential tremor is not associated with alpha-synuclein gene haplotypes.

A specific allele of the NACP-Rep1 polymorphism within the alpha-synuclein promoter was found to be associated both with Parkinson's disease and essential tremor. We repeated the association study on a large series of Italian patients with essential tremor using a panel of polymorphisms within the alpha-synuclein gene. Our results did not confirm the association reported previously and failed to identify a alpha-synuclein specific haplotype as susceptibility factor for essential tremor.     

Disorders of amino acid metabolism associated with epilepsy

Seizures are a common presenting manifestation in children with disorders of amino acid metabolism. However, seizures may be very common in some specific diseases, but are rare in other diseases. In patients with classical maple syrup urine disease (MSUD), seizures commonly occur in the neonatal stage. But in intermittent or intermediate MSUD, seizures may develop in a later stage, or are uncommon. Patients with nonketotic hyperglycinemia often present with early myoclonic encephalopathy in the first weeks of life. However, in patients with atypical variants, seizures may be rare. In addition, patients with sulfite oxidase deficiency, serine deficiency, or GABA-related disorders may also present with different types of seizures. In monoamine biosynthesis disorders, seizures are rare, but paroxysmal dystonia is frequently misdiagnosed as seizures. Therefore, the incidence of seizures in disorders of amino acid metabolism is variable. Timely diagnosis and early treatment may improve the prognosis of these disorders.     

CTLA4 exon 1 dimorphism is associated with primary progressive multiple sclerosis

The cytotoxic T-lymphocyte antigen 4 (CTLA4) is an important modifier of T-cell activation with down-regulatory properties upon B7 engagement. We investigated the association of the CTLA4 A/G dimorphism in exon 1 (+49) with disease susceptibility, disease course and severity. No differences in the allelic distribution of the G(49) allele between multiple sclerosis (MS) patients and the control group was found. However, the G(49) allele occurred in a significant higher percentage of patients with primary progressive MS compared to patients with bout onset of disease. The results suggest that dysregulation of CTLA4-driven down-regulation of T-cell function due a genetic dimorphism in exon 1 may be involved in the pathogenesis of different MS disease subtypes.     

Impaired binding of thrombin to thrombomodulin is associated with risk of deep vein thrombosis

The complex of thrombin and thrombomodulin (TM) activates protein C, and impaired binding of thrombin to TM may be a risk factor for thrombosis. In this study, we evaluated the reactivity of thrombin to TM by determining the TM-bound thrombin (TMBTh) to total thrombin generation (t-Th) ratio (TMBT ratio). We also examined whether a decreased TMBT ratio is associated with increased risk of thrombosis. TMBTh was measured on TM-coated plates. Thrombin was generated by addition of prothrombin time reagent to plasma. Levels of t-Th and TMBTh were expressed as percentages of the levels in pooled normal plasma. The study included 124 patients with deep vein thrombosis and 150 age- and sex-matched healthy subjects. The TMBT ratio (TMBTh/t-Th) was significantly lower in patients than in control subjects (p < 0.05). Among the 124 patients, 43 (34.7%) showed TMBT ratios below the 5th percentile value of control subjects, and the odds ratio (OR) for development of deep vein thrombosis was 9.4 (95% confidence interval [CI], 4.6-19.1). When patients with a deficiency of natural anticoagulant (antithrombin III, protein C, or protein S) were excluded from analysis, the TMBT ratio in 37 (42.5%) of the remaining 87 patients was below this cutoff point, and the OR (13.1; 95% CI, 6.4-26.9) was increased compared to that in the total patient group. These results suggest that it is possible to evaluate the reactivity of thrombin to TM by determining the TMBT ratio, and this ratio may be a predictor of deep vein thrombosis.     

The antidepressant effect of ketamine is not associated with changes in occipital amino acid neurotransmitter content as measured by [H]-MRS

The NMDA receptor antagonist ketamine can induce a rapid improvement in depressive symptoms that often endures for days after a single intravenous dose. The pharmacodynamic basis for this effect is poorly understood. Using a proton magnetic resonance spectroscopy ([¹H]-MRS) method that previously detected a normalization of amino acid neurotransmitter (AANt) content after chronic treatment with conventional antidepressant treatments, we examined whether the acute action of ketamine is associated with alterations in AANt content as well. Ten subjects with major depressive disorder (MDD) received saline, then ketamine in a fixed order, one week apart, under single-blind conditions. Each infusion was associated with three [¹H] MRS scans (baseline, 3 h and 48 h post-infusion) that measured glutamate, GABA and glutamine within the occipital cortex. Rating scales were administered before, during and after each infusion. The rapid (1 h) and sustained (at least 7 days) antidepressant effect we observed after ketamine infusion was not associated with either baseline measures of, or changes in, occipital AANt content. Dissociative symptoms were not correlated with changes in depression scores. While our results indicate that changes in occipital AANt content are not a correlate of ketamine's antidepressant action, this may only apply to the regional and temporal windows of our MRS measurements.     

Transporter-mediated GABA release induced by excitatory amino acid agonist is associated with GAD-67 but not GAD-65 immunoreactive cells of the primate retina

The release of GABA from amacrine and interplexiform cells after exposure to excitatory amino acids (EAAs) agonists was investigated by immunohistochemistry. Cebus monkey retinas were treated in vitro with 50 microM kainate (KA) or 5 mM L-Glutamate (L-Glu), for 30 min at 37 degrees C. The effects of the EAAs were measured by detecting immunocytochemically the GABA remaining in the tissue after stimulation. L-Glu and KA reduced the number of GABA-immunoreactive perikarya in the innermost part of the inner nuclear layer by approximately 60% and 80%, respectively, as compared to controls. The cell processes in the inner plexiform layer (IPL) were restricted to only three defined bands in the strata 1, 3 and 5, as compared to an intense and homogeneous labeling in the IPL of the untreated retinas. The effect of KA was inhibited by 100 microM CNQX, 100 microM NNC-711, or when Na(+) was replaced by choline. The release of GABA was Ca(2+)-independent, suggesting the mobilization of GABA from the cytoplasmic pool of this neurotransmitter. At least two subsets of retinal neurons including amacrine and interplexiform cells retained GABA-immunoreactivity after stimulation with EAAs, as revealed by glutamic acid decarboxylase (GAD) immunocytochemistry. Our results suggest that non-NMDA receptor activation by KA and glutamate are associated with the efflux of GABA from cells of the inner retina (amacrine and interplexiform cells). The data also show that cells containing GAD-67 released GABA via its transporter, while cells containing exclusively GAD-65 apparently did not release the neurotransmitter by the reversal of the transporter.     

Positive schizotypy is not associated with speech abnormality

Aim: This study examined whether speech abnormalities typical of formal thought disorder in schizophrenia vary with the degree of positive schizotypy in the healthy population. We hypothesized that participants with high levels of positive schizotypy would show greater abnormality in speech relative to those with low levels of positive schizotypy. Methods: Participants (n = 107) were prescreened with a positive schizotypy scale. Those meeting criteria for either high (n = 23) or low (n = 27) schizotypy provided speech samples which were assessed with a clinical though disorder rating scale (Thought and Language Index) for the presence of abnormality. Results: No significant differences were found in positive (P = 0.25) or negative (P = 0.21) speech abnormality between the high and low schizotypy groups. Conclusion: Although schizotypy is normally distributed in the general population, speech abnormality is not. Thus, the presence of aberrations in speech may predict risk of psychosis. Potential implications for risk assessment are discussed.     

Saitohin gene is not associated with Alzheimer's disease

BACKGROUND: The deposition of tau protein in neurofibrillary tangles constitutes an important feature of many neurodegenerative disorders, including Alzheimer's disease. A polymorphic gene, saitohin (STH), nested within the tau gene (microtubule associated protein tau, MAPT), was recently identified and an association of a non-synonymous polymorphism in STH with increased risk for Alzheimer's disease was suggested. Objective and methods: To test the above hypothesis in a case-control association study of two independent white populations within Switzerland and Greece, comparing genotype and allele frequencies from 225 Alzheimer's disease patients and 144 healthy control subjects. RESULTS: No differences in allelic or genotypic distributions between Alzheimer's disease patients and controls was found in the individual samples (Swiss/Greek) or in the combined sample. Stratification for the presence of apolipoprotein E (APOE) epsilon 4 allele, sex, or age did not show significant effects in the populations studied, nor was there an effect on the age of onset. CONCLUSIONS: No evidence was found for an association of the non-synonymous polymorphism (Q7R) in STH and Alzheimer's disease. This finding is in line with earlier studies showing no association between MAPT and Alzheimer's disease.     

The antidepressant effect of ketamine is not associated with changes in occipital amino acid neurotransmitter content as measured by [(1)H]-MRS

The NMDA receptor antagonist ketamine can induce a rapid improvement in depressive symptoms that often endures for days after a single intravenous dose. The pharmacodynamic basis for this effect is poorly understood. Using a proton magnetic resonance spectroscopy ([(1)H]-MRS) method that previously detected a normalization of amino acid neurotransmitter (AANt) content after chronic treatment with conventional antidepressant treatments, we examined whether the acute action of ketamine is associated with alterations in AANt content as well. Ten subjects with major depressive disorder (MDD) received saline, then ketamine in a fixed order, one week apart, under single-blind conditions. Each infusion was associated with three [(1)H] MRS scans (baseline, 3h and 48 h post-infusion) that measured glutamate, GABA and glutamine within the occipital cortex. Rating scales were administered before, during and after each infusion. The rapid (1h) and sustained (at least 7 days) antidepressant effect we observed after ketamine infusion was not associated with either baseline measures of, or changes in, occipital AANt content. Dissociative symptoms were not correlated with changes in depression scores. While our results indicate that changes in occipital AANt content are not a correlate of ketamine's antidepressant action, this may only apply to the regional and temporal windows of our MRS measurements.     

mtDNA A3243G MELAS mutation is not associated with multigenerational female migraine

The authors searched for mitochondrial DNA (mtDNA) A3243G mutation in peripheral blood leukocytes from female migraine patients with pure matrilinear history of migraine along two or three generations. The current study was designed to exclude any male transmission of the disease. The mutation was absent in all patients. We conclude that mtDNA A3243G mutation does not contribute to the pathogenesis of pure matrilinear multigenerational migraine with or without aura.     

Wake-up stroke is not associated with obstructive sleep apnea

Objective/BackgroundObstructive sleep apnea is a risk factor for stroke. This study sought to assess the relationship between obstructive sleep apnea (OSA) and wake-up strokes (WUS), that is, stroke symptoms that are first noted upon awakening from sleep.Patients/methodsIn this analysis, 837 Brain Attack Surveillance in Corpus Christi (BASIC) project participants completed an interview to ascertain stroke onset during sleep (WUS) versus wakefulness (non-wake-up stroke, non-WUS). A subset of 316 participants underwent a home sleep apnea test (HSAT) shortly after ischemic stroke to assess for OSA. Regression models were used to test the association between OSA and WUS, stratified by sex.ResultsOf 837 participants who completed the interview, 251 (30%) reported WUS. Among participants who underwent an HSAT, there was no significant difference in OSA severity [respiratory event index (REI)] among participants with WUS [median REI 17, interquartile range (IQR) 10, 29] versus non-WUS (median REI 18, IQR 9, 30; p = 0.73). OSA severity was not associated with increased odds of WUS among men [unadjusted odds ratio (OR) 1.011, 95% confidence interval (95% CI) 0.995, 1.027] or women (unadjusted OR 0.987, 95% CI 0.959, 1.015). These results remained unchanged after adjustment for age, congestive heart failure, body mass index, and pre-stroke depression in men (adjusted OR 1.011, 95% CI 0.994, 1.028) and women (adjusted OR 0.988, 95% CI 0.959, 1.018).ConclusionsAlthough OSA is a risk factor for stroke, the onset of stroke during sleep is not associated with OSA in this large, population-based stroke cohort.     

Norepinephrine transporter gene polymorphism is not associated with susceptibility to major depression.

The monoamine neurotransmitters serotonin, norepinephrine and dopamine have been implicated in the pathogenesis of depression, schizophrenia and mood disorders. The mechanism of action of certain antidepressant drugs, particularly the tricyclics and the newly available norepinephrine and serotonin reuptake inhibitors (NSRIs) drugs, venlafaxine and nefazodone, suggest that the norepinephrine transporter, which is a target for these antidepressant drugs, and its malfunction may be involved in major depression. In this association study, we tested the hypothesis that variants of the human norepinephrine transporter (NET) gene confer susceptibility to major depression. One hundred and five patients with major depression and 74 unrelated matched controls were analyzed for a silent 1287G/A polymorphism (NET-8) in exon 9 of the NET gene. No significant differences in genotype or allele frequencies were found between controls and patients, nor between subgroups of depressed patients classified by suicidal ideation. In addition, 60 controls and 60 patients were genotyped for a missense substitution Thr99Ile in exon 2 of the NET gene (NET-1), but only one control was heterozygous for this variant. These results suggest that the NET gene is unlikely to be involved in the susceptibility to major depression.     

Hyperglycemia is not associated with mortality in bacterial meningitis

An association between hyperglycemia and mortality from cerebral ischemia has been reported in both animals and man. Recently, a similar observation has been made in animals with bacterial meningitis. The present study of 83 patients with bacterial meningitis showed no association between initial serum glucose concentration and subsequent mortality. Therefore, no therapeutic recommendations regarding optimal blood glucose levels in patients with meningitis can be made at this time.     

Werner helicase polymorphism is not associated with Alzheimer's disease

Alzheimer disease (AD) is the most common neurodegenerative disorder in the elderly and is also considered a progeroid genetic syndrome. The etiology of AD is complex and the mechanisms underlying its pathophysiology remains to be clarified. Werner syndrome (WS) is a rare autosomal recessive disorder characterized as a segmental progeroid syndrome. The gene (WRN) was recently identified. Its product acts as a DNA helicase and exonuclease. This study investigates the association of AD with the WRN 1367 polymorphisms in samples of 67 DA patients, 56 elderly healthy and 66 young healthy controls. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. We observed that the genotype distributions of WRN 1367 variants were within Hardy-Weinberg equilibrium in all subject samples. Furthermore, chi-square test comparison for genotype distributions and allele frequencies did not reveal any significant difference among the three groups of subjects (P>0.05). These results support the idea that these variants are not involved as a risk factor for developing AD.