By the time a clinical diagnosis of Parkinson's disease (PD) is made, a significant loss of dopaminergic neurons has already occurred. Identifying patients in the period between the presumed onset of dopaminergic cell loss and the appearance of clinical parkinsonism may be of major importance in the development of effective neuroprotective treatment strategies. In an effort to develop a feasible strategy to detect preclinical PD, a combination of olfactory processing tasks, including odor detection, odor identification, and odor discrimination was used to select groups of hyposmic and normosmic individuals from a total of 250 relatives (parents, siblings, or children) of subjects with PD. Single photon emission computed tomography (SPECT) with [123I]beta-CIT as a dopamine transporter ligand was used to assess nigrostriatal dopaminergic function in 25 hyposmic and 23 normosmic relatives of PD patients. An abnormal reduction in striatal dopamine transporter binding was found in 4 out of 25 hyposmic relatives of PD patients, two of whom subsequently developed clinical parkinsonism, and in none of the 23 normosmic relatives. These observations demonstrate that subclinical reductions in dopamine transporter binding can be detected in asymptomatic relatives of sporadic PD patients by means of [123I]beta-CIT and SPECT. The results further indicate that olfactory deficits may precede clinical motor signs in PD.
for the Octopus Study Group C ORONARY ARTERY BYPASS graft (CABG) surgery effectively relieves angina but is associated with significant cerebral morbidity. 1 This has largely been attributed to the use of cardiopulmonary bypass. 1,2 Cardiopulmonary bypass requires cannulation and crossclamping of the ascending aorta, which may dislodge atheromatous macroemboli, leading to stroke. 3 Cardiopulmonary bypass also increases the permeability of the blood-brain barrier and generates microemboli, which may adversely affect cognitive function. 4,5 The incidence of cognitive decline in the first year after surgery ranges from less than 5% to more than 30%, depending both on patient characteristics and on the definition of decline that is used. 2,6 Stroke occurs in approximately 3% of patients undergoing CABG surgery. 1 The desire to avoid the perceived ill effects of cardiopulmonary bypass has led to a renewed interest in bypass surgery on the beating heart (off-pump CABG surgery). This has been stimulated by the development of cardiac stabilizers, which facilitate the construc-Author Affiliations: Departments of Anesthesiology (Drs van Dijk and Kalkman and Ms Spoor), Psychiatry (Dr Hijman), Cardiology (Drs Nathoe and Borst), and Cardiothoracic Surgery (Dr Jansen
Neurocognitive dysfunction is a frequently occurring complication of coronary artery bypass grafting. The etiologic contribution of cardiopulmonary bypass to this complication will remain unclear until a randomized trial that directly compares off-pump and on-pump bypass surgery is carried out.
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