Diffusion-weighted MR imaging in carotid angioplasty and stenting with protection by the reversed carotid arterial flow.

BACKGROUND AND PURPOSE: Distal embolism during carotid angioplasty with stent (CAS) can be protected by a flow-reversal device. Diffusion-weighted MR imaging was used to evaluate this protective procedure and perform a comparison with the control. METHODS: Cases of CAS with protection procedures were included in this study. Sixty-five men (68 procedures) and 5 women (5 procedures), with an average age of 68.8 years, having severe carotid stenosis were treated in our department between 2002 and 2004. Eleven cases were treated with the Parodi Anti-Emboli System, with which the internal carotid blood flow is reversed by simultaneous occlusion of the proximal common carotid artery and external carotid artery. Diffusion-weighted MR imaging was performed within 1-3 days after CAS. As controls, data from diffusion-weighted MR imaging in 26 patients who had diagnostic angiography were included. RESULTS: Diffusion-weighted MR imaging in diagnostic angiography showed 11.5% appearance of ischemic spots after procedures. In the Parodi Anti-Emboli System, this value was 18.2%. In the CAS group, ischemic lesions appeared only in the hemisphere ipsilateral to carotid stenosis. There were no ischemic lesions in the opposite carotid or vertebrobasilar territory. The appearance rate of new ischemic spots was not significantly different between the control group and the group of CAS with Parodi Anti-Emboli System (chi2 test, P = .6227, Fisher exact method). CONCLUSIONS: Protection results obtained with the Parodi system were excellent and comparable with conventional angiography.

Ventilatory control during exercise in normal children.

We investigated the relation between age and respiratory control during exercise in 80 children aged 6.4-17.6 y (42 male, age, 11.6 +/- 3.3 y; body weight, 41.3 +/- 14.7 kg; and 38 female, age, 12.6 +/- 2.7 y; body weight, 42.5 +/- 9.3 kg). Exercise tests were performed on a treadmill after a standard symptom-limited Bruce protocol. Data were analyzed separately for boys and girls. At rest and at peak exercise, the ratio of minute ventilation to carbon dioxide production (VE/VCO2), the ratio of effective alveolar ventilation to carbon dioxide production (VA/VCO2), the ratio of pulmonary dead space to tidal volume (Vd/Vt), and arterial PCO2 (PaCO2) were not correlated with age. At the exercise intensity of ventilatory anaerobic threshold, the PaCO2 increased, and the VA/VCO2 decreased, significantly with age, whereas the Vd/Vt was not related to age. Linear regression analysis demonstrated that the slope of the relationship between VE and VCO2 (deltaVE/deltaVCO2) and the slope of the relationship between VA and VCO2 (deltaVA/deltaVCO2) decreased with age. There were no gender differences in the regression slopes and the intercepts of the relationships. Results show that younger children breathe more during exercise to eliminate a given amount of CO2 to keep PaCO2 set point slightly but significantly lower than older children. This age dependence must be considered in investigating ventilatory control during exercise in children.

Effects of N-(2-ethylhexyl)-3-hydroxybutyramide hydrogen succinate on the metabolisms of monoamines in the rat brain.

N-(2-Ethylhexyl)-3-hydroxybutyramide hydrogen succinate (M-2H) has been reported to increase REM sleep. The effects of M-2H on the metabolisms of monoamines which have been implicated in the regulation of the sleep-wakefulness cycle were studied in rats. M-2H (500 mg/kg p.o.) increased the levels of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid and 3-methoxy-4-hydroxyphenylethyleneglycol sulfate in various regions of the rat brain. However, no appreciable changes occurred in levels of serotonin (5-HT), norepinephrine, dopamine, or 3,4-dihydroxyphenylacetic acid. The effect of M-2H (500 mg/kg p.o.) on 5-HT metabolism was investigated with intraventricularly-injected [14C]-5-HT. Although [14C]-5-HT level was not significantly changed, [14C]-5-HIAA level was above control level in four brain regions such as the hypothalamus, hippocampus, midbrain and pons-medulla at 3 h after the administration of M-2H. M-2H retarded the efflux of intraventricularly-injected [14C]-5-HIAA in all brain regions except the cortex. These results suggest that M-2H preferentially impaired the transport system for acid metabolites of monoamines, resulting in increase of monoamine metabolite levels in the brain.