Cerebellar involvement in motor and non-motor sequence learning was examined with serial reaction time tasks (SRT). Our sample consisted of 8 children and adolescents who had undergone surgical removal of a benign posterior fossa tumor (PFT) during childhood. None of them had undergone chemotherapy or cranial radiation therapy (CRT). Ages ranged from 1-11 years at surgery and 9-17 years at testing. The children were tested not earlier than 2.5 years after surgery (M = 5.9 years), enabling brain plasticity and recovery of functions. Their performance was compared with a matched control sample. The PFT group was not impaired in the implicit learning of sequences, as reflected in their performance in blocks with a repeated sequence, both before and after a random block. However, in the perceptual task, their performance deteriorated more than that of the control group when a random block was introduced, suggesting that it was more difficult for the patients to respond flexibly or change their response set when encountering changing task demands. These results are in line with another study by our group on task switching with the same patients. 相似文献
Background: The cardiotoxic mechanism of local anesthetics may include interruption of cardiac sympathetic reflexes. The authors undertook this investigation to determine if clinically relevant concentrations of bupivacaine and levobupivacaine interfere with exocytotic norepinephrine release from cardiac sympathetic nerve endings.
Methods: Rat atria were prepared for measurements of twitch contractile force and 3[H]-norepinephrine release. After nerve endings were loaded with 3[H]-norepinephrine, the tissue was electrically stimulated in 5-min episodes during 10 10-min sampling periods. After each period, a sample of bath fluid was analyzed for radioactivity and 3[H]-norepinephrine release was expressed as a fraction of tissue counts. Atria were exposed to buffer alone during sampling periods 1 and 2 (S1 and S2). Control atria received saline (100 [mu]l each, n = 6 atria) in S3-S10. Experimental groups (n = 6 per group) received either bupivacaine or levobupivacaine at concentrations (in [mu]M) of 5 (S3-S4), 10 (S5-S6), 30 (S7-S8), and 100 (S9-S10).
Results: Bupivacaine and levobupivacaine decreased stimulation-evoked fractional 3[H]-norepinephrine release with inhibitory concentration 50% values of 5.1 +/- 0.5 and 6.1 +/- 1.3 [mu]m. The inhibitory effect of both local anesthetics (~70%) approached that of tetrodotoxin. Local anesthetics abolished the twitch contractions of atria with inhibitory concentration 50% values of 12.6 +/- 5.0 [mu]m (bupivacaine) and 15.7 +/- 3.9 [mu]m (levobupivacaine). In separate experiments, tetrodotoxin inhibited twitch contractile force by only 30%. 相似文献
Myotonic dystrophy is an inherited multi-system disease. Its pathophysiology leading to muscle malfunction and damage is not well understood. 23Na NMR spectroscopy was applied here for an in vivo comparative study of the calf muscles of 7 myotonic dystrophy patients at various stages of the disease and 11 healthy volunteers. Both the total sodium content, expressed as the ratio of the 23Na and 1H water signals, and the fast transverse relaxation time, T21, determined from the triple quantum-filtered spectra, increased in correlation with the severity of the disease. The results demonstrate that 23Na NMR enables the quantitation of myotonic dystrophy progression. 相似文献
A rare case is reported of a young woman who suffered from suprascapular nerve entrapment syndrome (SNES) of the right side and two years later developed the same syndrome on the left. At the first operation an anomalous bifid transverse ligament was found and cut. The combination of pressure effect from the congenital defect together with frequent protraction of the shoulder due to her work as a physical education teacher caused triggering of the SNES. The clinical course, electromyographic findings, and differential diagnosis are reported. Cutting of the anomalous ligament on both sides brought relief from pain, weakness, and atrophy of the shoulder muscles, enabling the patient to return to work. 相似文献
The purpose of our study was to prospectively evaluate the striatal uptake of 123I-labeled N-(3-fluoropropyl)-2beta-carbomethoxy-3beta-(4-iodophenyl)nortropane (FP-CIT) and the response to l-dopa therapy in patients with cerebrovascular disease (CVD) who develop clinical symptoms of vascular parkinsonism (VP). METHODS: Twenty consecutive patients who developed VP in the course of CVD were prospectively enrolled in the study. All patients had CT evidence of CVD (17 patients had lacunar infarcts, 3 patients had territorial strokes). The clinical stage of the patients was assessed using the Hoehn and Yahr scale, and the severity of the symptoms was measured using the Unified Parkinson's Disease Rating Scale score. Ten age-matched subjects were used as controls. SPECT was performed 180 min after injection of 185 MBq 123I-FP-CIT using a dual-head gamma-camera. The ratio of the mean specific-to-nonspecific striatal binding for the entire striatum, caudate, and putamen was calculated in all patients and compared with that of controls. Putamen-to-caudate binding ratios were compared as well. The response to therapy was compared between patients with normal and abnormal 123I-FP-CIT binding. RESULTS: No correlation was found between any of the clinical variables and response to therapy in patients with VP. Nine patients had normal striatal 123I-FP-CIT binding with no significant differences in striatal or subregional binding ratios compared with those of the controls. In contrast, 11 patients had significantly diminished striatal binding compared with that of controls (P < 0.001). Subanalyses showed significantly decreased binding in the caudate (P < 0.04 and P < 0.01 for the right and left caudate, respectively), diminished binding in the putamen (P < 0.04 and P < 0.01 for the right and left putamen, respectively), and a decreased putamen-to-caudate ratio on the right side (P < 0.001). The latter ratio was not significant on the left. Two of the 3 patients with territorial strokes had significantly diminished striatal 123I-FP-CIT binding in the hemisphere contralateral to the CT lesion. All 9 patients with normal scan findings had a poor response to L-dopa. Six of 11 patients with abnormal studies had no response to L-dopa, whereas 5 patients had a good response (P < 0.03). CONCLUSION: The diagnosis of VP cannot be accurately confirmed on the basis of clinical features alone because CVD may alter the typical presentation of PD. Functional imaging with 123I-FP-CIT is highly recommended in patients with CVD who develop symptoms of VP to confirm or exclude the existence of nigrostriatal dopaminergic degeneration. Identifying a subset of patients with reduced 123I-FP-CIT binding in the striatum is important for better treatment selection. 相似文献