Intracranial circulation: pulse-sequence considerations in three- dimensional (volume) MR angiography

The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.     

Physiological analysis of simple rapid movements in patients with cerebellar deficits.

Patients with cerebellar deficits made elbow flexion movements as rapidly as possible for three different angular distances. Electromyographic activity of biceps and triceps and the kinematics of the movements were analysed. Results were compared with those of normal subjects making both rapid and slow movements. In the patients, the first agonist burst of the biceps was frequently prolonged regardless of the distance or speed of the movement. The most striking kinematic abnormality was prolonged acceleration time. The pattern of acceleration time exceeding deceleration time was common in patients but uncommon in normal subjects. The best kinematic correlate of the duration of the first agonist burst was acceleration time. Altered production of appropriate acceleration may therefore be an important abnormality in cerebellar dysfunction for attempted rapid voluntary movements.     

Progesterone for the prevention of preterm birth in women with multiple pregnancies: the AMPHIA trial

Background

Adequate vitamin D concentrations during pregnancy are necessary to neonatal calcium homeostasis, bone maturation and mineralization. The aim of study is to evaluate serum vitamin D concentrations in mothers and their newborns and effect of vitamin D deficiency on pregnancy outcomes.

Methods

552 pregnant women were recruited from Tehran University educating hospitals in the winter of 2002. Maternal and cord blood samples were taken at delivery. The serum was assayed for 25-hydroxyvitamin D3, calcium, phosphorus and parathyroid hormone.

Results

The prevalence of vitamin D deficiency in maternal and cord blood samples were 66.8% and 93.3%, respectively (<35 nmol/l). There was significant correlation between maternal and cord blood serum concentrations of vitamin D. In mothers with vitamin D deficiency, cord blood vitamin D concentrations was lower than those from normal mothers (P = .001). Also, a significant direct correlation was seen between maternal vitamin D intake and weight gain during pregnancy.

Conclusion

Consideration to adequate calcium and vitamin D intake during pregnancy is essential. Furthermore, we think it is necessary to reconsider the recommendation for vitamin D supplementation for women during pregnancy.     

Human fetal dopamine neurons grafted into the striatum in two patients with severe Parkinson's disease. A detailed account of methodology and a 6-month follow-up

By using stereotaxic surgical techniques, ventral mesencephalic tissues from aborted human fetuses of 8 to 10 weeks' gestational age were implanted unilaterally into the striata in two patients with advanced Parkinson's disease. The patients were treated with a cyclosporine, azathioprine, and steroid regimen to minimize the risk for graft rejection. They were examined for 6 months preoperatively and 6 months postoperatively and continued to receive the same doses of antiparkinsonian medication. There were no significant postoperative complications. No major therapeutic effect from the operation was observed. However, in the clinical tests, both patients showed small but significant increases of movement speed for repeated pronation-supination, fist clenching, and foot lifting. The rate of walking also increased in the one patient tested. For both patients, there was an initial worsening postoperatively, followed by improvement vs preoperative performance at 1 to 3 months. Both patients also showed significant improvement in the magnitude of response to a single dose of levodopa (L-dopa), but there was no increase in the duration of drug action. The motor readiness potential increased in both patients postoperatively, primarily over the operated hemisphere. Neurophysiological measurements also showed a more rapid performance of simple and complex arm and hand movements on the side contralateral to transplantation in one patient at 5 months postoperatively. Positron emission tomography demonstrated no increased uptake of 6-L-(18F)-fluorodopa in the transplanted striatum at 5 and 6 months. Taken together, these results suggest that the fetal nigral implants may have provided a modest improvement in motor function, consistent with the presence of small surviving grafts. Although our results support further scientific experimentation with transplantation in Parkinson's disease, widespread clinical trials with this procedure are probably not warranted at this time.     

Exploring Theta Burst Stimulation as an intervention to improve motor recovery in chronic stroke.

OBJECTIVE: To explore the effects of a single session of repetitive Transcranial Magnetic Stimulation, given as Theta Burst Stimulation, on behavioural and physiological measures of hand function in chronic stroke patients. METHODS: Six chronic stroke patients with incomplete recovery of the hand were tested under three conditions: excitatory TBS over the stroke hemisphere (iTBS(SH)), inhibitory TBS (cTBS(IH)) over the intact hemisphere and sham stimulation. Behavioural outcomes included simple and choice reaction time paradigms. Physiological effects were assessed using single pulse TMS on both sides. Changes were sought for up to 40min after TBS. RESULTS: Immediately after iTBS(SH) simple reaction times in the paretic hands were decreased and, compared to sham stimulation, remained significantly shorter throughout the testing period. The amplitude of the MEPs at rest and during background contraction and the area under the Input-Output curves were also increased on the stroke side after iTBS(SH). cTBS(IH) suppressed the MEPs evoked in the healthy hands but did not change motor behaviour or the electrophysiology of the paretic hands. No side effects were encountered. CONCLUSIONS: TBS seems safe in chronic stroke patients. iTBS over the stroke hemisphere transiently improved motor behaviour and corticospinal output in the paretic hands. SIGNIFICANCE: Excitatory TBS may represent a useful rTMS protocol to apply to the stroke hemisphere in future longer term therapy trials.