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Paroxysmal Autonomic Instability With Dystonia
Blackman and colleagues describe paroxysmal autonomic instability with dystonia in patients with brain injury. This appears to be a distinctive syndrome following brain injury that can mimic other life-threatening conditions. Early recognition will lead to fewer diagnostic tests and an improved outcome.
Plasma Amyloid, Hypercholesterolemia, and Statins: Linkage to Alzheimer Disease?
Höglund and colleagues studied the relationship between statins, lowered levels of cholesterol, and plasma levels of β-amyloid(1-40) and β-amyloid(1-42). Patients treated with statins had plasma cholesterol levels that were reduced by 56%, but there was no significant change in levels of plasma β-amyloid. The authors' data do not support an effect of statins on the processing of plasma amyloid precursor protein (APP) in patients. Thus, if statins have a protective effect against Alzheimer disease, it is apparently unrelated to APP processing peripherally. Although statins may still affect APP processing in the brain or be protective by other mechanisms, this important study narrows the possibilities.
Genetic Risk for Alzheimer Disease
The gene encoding myeloperoxidase, MPO, and the gene encoding α2-macroglobulin, A2M, are both involved in the molecular pathways leading to β-amyloid deposition. Two polymorphic sites in these genes (MPO-G/A and A2M-Ile/Val) have been associated with Alzheimer disease (AD). Zappia and colleagues have investigated the interactions between MPO, A2M, and apolipoprotein E gene (APOE) polymorphisms and the risk of AD. Their data show an increased risk for AD with these polymorphisms and thus greatly expand our knowledge of the molecular basis of AD.
Tissue Plasminogen Activator: Valuable but Restricted Use
The rate of tissue plasminogen activator (tPA) use for stroke in the community of Cleveland, Ohio, and the reasons why patients were excluded from this important thrombolytic therapy were studied by Katzan and colleagues. Delay in presentation and specific neurological criteria were the most common reasons for tPA exclusion. Intravenous tPA use in a community setting compares favorably with that seen in academic medical settings. The authors' data offer a means to develop strategies to improve the degree of patient inclusion.
Genetic Risk for Stroke in Young Adults
Serum paraoxonase (PON1), a high-density lipoprotein–associated esterase with antioxidant and antiatherogenic properties, has been implicated in the pathogenesis of cardiovascular disease. Q192R and L55M coding region polymorphisms and promoter region polymorphisms were found to be important in determining PON1 levels. Voetsch and colleagues studied PON1 promoter polymorphisms in arterial ischemic stroke in young adults. They found that the PON1−107T allele is associated with an increased risk of arterial ischemic stroke. These data show that a paraoxonase gene polymorphism is associated with stroke. The authors' findings will be useful to explain the growing genetic cascade of events that leads to stroke in young adults.
Imaging Status Epilepticus in Patients With Cancer
Hormigo and colleagues studied patients with cancer who had reversible magnetic resonance imaging (MRI) abnormalities from nonconvulsive status epilepticus and whose mental status and MRI findings were initially thought to be caused by a structural lesion related to the underlying tumor. Their observation is of considerable value in patient treatment and shows that cortical enhancement on MRI results in patients with cancer who have altered mental status may be due to nonconvulsive status epilepticus and not recurrent or metastatic tumor.
New Magnetic Resonance Imaging Approaches in Early Multiple Sclerosis
Magnetization transfer and diffusion tensor magnetic resonance imaging were used by Mezzapesa and colleagues to assess the extent of microscopic tissue damage of the brain and cervical cord in patients with early-onset multiple sclerosis. These magnetic resonance imaging approaches are able to detect early abnormalities in multiple sclerosis and provide insight into the pathogenesis of minimal tissue damage in this disease.
Neuroimaging in Human Immunodeficiency Virus Encephalitis: Correlations With Neuropathologic Abnormalities
Archibald and colleagues examined the relationship between findings on premortem magnetic resonance images and postmortem neuropathologic evidence of human immunodeficiency virus encephalitis (HIVE) as well as specific aspects of neurodegeneration. Cerebral and cerebellar volume loss and an increased white matter signal were noted. This signal elevation in white matter predicted the autopsy diagnosis of HIVE and the extent of dendritic loss. This correlative imaging and neuropathologic study is valuable in determining the degree of HIVE and will be of considerable use in the assessment of patients at risk for developing this disease.
Amyloid, Neurofibrillary Tangles, and the Degree of Alzheimer Disease Dementia
Bennett and colleagues tested the hypothesis that the association of amyloid load with clinical Alzheimer disease (AD) and cognitive impairment is mediated through neurofibrillary tangles. Using logistic regression analyses, they found that each 1% increase in amyloid load was associated with about a 50% increase in the odds of clinical AD and that each neurofibrillary tangle was associated with more than a 20% increase in the odds of clinical AD. They conclude that the effect of amyloid deposition on clinical disease is actually mediated by neurofibrillary tangles. This is an interesting and unique study and offers a new perspective on the causation of AD dementia.
Body Mass in Essential Tremor
A reduction in body mass index is seen in neurodegenerative diseases and is found in patients with essential tremor, as reported by Dogu and colleagues. It is important for physicians to be aware of the potential for low body mass index in their patients with essential tremor so that nutrition can be addressed as part of the treatment plan.
Subthalamic Stimulation in Parkinson Disease: With or Without Anesthesia?
Maltête and colleagues report that subthalamic nucleus (STN) stimulation in patients with Parkinson disease considerably improves motor disability. Fifteen patients with Parkinson disease who underwent bilateral implantation of electrodes within the STN received general anesthesia because of severe anxiety, poorly tolerated off-period dystonia, or respiratory difficulties. Their postoperative outcome was compared with that of patients who underwent the same procedure with local anesthesia. Compared with surgically treated patients who were given local anesthesia, the residual parkinsonian motor score with stimulation (with or without levodopa) and the intensity of stimulation were higher in surgically treated patients who received general anesthesia. General anesthesia for STN electrode placement and stimulation remains a beneficial option for specific patients in whom local anesthesia is less desirable.
Non-tau-mutational Frontotemporal Dementia With Inclusions
Wilhelmsen and colleagues describe the clinical, neuropathologic, and genetic features of a large family with frontotemporal dementia that does not have a MAPτ coding or splice regulatory mutation. They conclude that this unique family has, as the most probable location for the mutation, a region on chromosome 17q distal to the MAPτ locus. An autopsy from an affected family member shows distinctive tau and α-synuclein inclusions. Editorial perspective is provided by Andrew Kertesz, MD, FRCPC.
This Month in Archives of Neurology. Arch Neurol. 2004;61(3):316–317. doi:10.1001/archneur.61.3.316
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