Nigral dopaminergic projections to the striatum are targeted in Parkinson's disease (PD). The extent of the degeneration of the dopaminergic system in PD can be visualised by dopamine transporter imaging using single-photon emission tomography (SPET). In this study in 188 patients with PD, we analysed the image patterns and compared them with the clinical features in order to verify the usefulness of technetium-99m TRODAT-1 brain SPET in the evaluation of patients with PD. Two independent readers visually assessed SPET slices from three brain axes according to a "fine" visual scale; results were also grouped according to a "rough" visual scale. Results of both visual and semi-quantitative analyses were compared among patients with different stages of PD and healthy controls. There was good agreement between the readers in the interpretation of the image patterns [kappa statistic (kappa)=0.85 for the presence of PD; kappa=0.88 for the rough scale and 0.81 for the fine scale]. Good concordance was obtained when visual interpretation was used to evaluate the presence of PD (sensitivity = 98%, specificity = 86%, kappa = 0.85). Semi-quantitative analyses revealed significant negative correlations between both striatal and putaminal uptake and disease severity as assessed using the Hoehn and Yahr scale (rho = -0.89 and -0.93 respectively). An apparent decrease in striatal uptake in early PD, hardly discernible from the uptake level in advanced PD, was commonly found in visual analyses. The results suggest that both visual and semi-quantitative analyses of 99mTc-TRODAT-1 SPET images reflect neurodegeneration in PD, and that 99mTc-TRODAT-1 SPET represents an adequate means for evaluation of the status of patients with PD.
The purpose of the present study was to investigate the modulatory actions of adrenoreceptor agonists on N-methyl-D-aspartate (NMDA)-induced pressor effect in rostral ventrolateral medulla (RVLM). These drugs were locally applied into RVLM of urethane-anesthetized Sprague-Dawley rats through multibarrel pipettes. Microinjection of NMDA increased the arterial pressure, an effect which was abolished by pretreatment with clonidine, whereas neither the beta-adrenergic agonist isoproterenol nor the alpha 1-adrenergic agonist phenylephrine did alter this pressor response. Previous experiments demonstrated that clonidine binds to noradrenergic alpha 2 and imidazoline receptors in the RVLM. Norepinephrine, which has high affinity for the alpha 2 receptor and low affinity to the imidazoline receptor, partially antagonized NMDA-induced hypertension. On the other hand, administration of selective imidazoline receptor antagonist idazoxan partially reversed clonidine-mediated antagonism of NMDA. Taken together, these results suggest that clonidine may modulate the excitatory amino acid-induced pressor response through noradrenergic alpha 2 and imidazoline receptors in the RVLM.
Hereditary protein C deficiency is inherited primarily as an autosomal dominant trait with incomplete penetrance. Arterial thrombosis, especially of the intracranial arteries, due to this deficiency is relatively rare. A 31-year-old man was admitted to our department because of sudden onset of neurological symptoms. Magnetic resonance imaging of the brain disclosed an acute ischemic infarction of the area supplied by the left middle cerebral artery. Protein C antigen was 40.7% (77-129%) and protein C activity was 46.3% (70-140%). No other possible associated causes of stroke were present. A survey of his relatives for protein C deficiency showed this deficiency in his mother, brother, sister and nephews. Protein C concentrations should be determined in cases of ischemic stroke in all young patients with no other major risk factors. Once protein C deficiency is detected, a search for protein C deficiency in the patient's relatives should be performed to prevent the occurrence of ischemic strokes.
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