Umbilical artery half peak systolic velocity deceleration time throughout pregnancy and its role in fetuses with bradycardia

OBJECTIVES

To describe a new technique for Doppler waveform quantification of the fetal umbilical artery, the half peak systolic velocity (h-PSV) deceleration time, which measures the time that it takes a single flow velocity waveform to halve its maximum systolic velocity. As this measurement is independent of fetal heart rate, its role in the evaluation of placental vascular resistance in fetuses with bradycardia was also explored.

METHODS

The umbilical artery impedance indices and the h-PSV deceleration time were measured in 532 normal singleton fetuses from 17 to 41 weeks of gestation. A nomogram was established and its usefulness in assessing fetuses with bradycardia was evaluated.

RESULTS

The relationship between umbilical artery h-PSV deceleration time and gestational age was best described by a linear formula (y = 6.5523x + 12.41; R(2) = 0.6346), h-PSV deceleration time increasing by 6.6 ms per week. The correlation coefficients for the 95(th), 50(th) and 5(th) centiles were 0.97, 0.98 and 0.98, respectively. Measurement of h-PSV deceleration time was reproducible, with interobserver and intraobserver variabilities of 10.7% and 7.4%, respectively. Among fetuses with bradycardia (n = 7), the h-PSV deceleration time was above the 5(th) centile in all cases, suggesting normal placental function in spite of abnormally increased impedance indices obtained with traditional Doppler indices in six.

CONCLUSIONS

The h-PSV deceleration time increases linearly during the second and third trimesters of pregnancy. As its measurement is reproducible and independent of heart rate, it may be useful in the assessment of well-being in fetuses with bradycardia.

Intraoperative radiation therapy in malignant glioma: early clinical results

Intraoperative radiation therapy (IORT) with high energy electron beams is a treatment modality that has been included in multimodal programs in oncology to improve local tumor control. From August 1991 to December 1993, 17 patients with primary (8) or recurrent (9) high grade malignant gliomas, anaplastic astrocytoma (4), anaplastic oligodendroglioma (6) and glioblastoma multiforme (7), underwent surgical resection and a single dose of 10-20 Gy intraoperative radiation therapy was delivered in tumor bed. Fourteen patients received either pre-operative (8) or post-operative (6) external beam radiation therapy. Primary gliomas: 18-months actuarial survival rate has been 56% (range: 1-21+ months) and the median survival time has not yet been achieved. Four patients developed tumor progression (median time to tumor progression: 9 months). Recurrent gliomas: 18-months actuarial survival rate and median survival time has been 47% and 13 months (range: 6-32+ months) respectively. The median time to tumor progression was 11 months. No IORT related mortality has been observed. IORT is an attractive, tolerable and feasible treatment modality as antitumoral intensification procedure in high grade malignant gliomas.

Stereotactic radiosurgery of the foramen magnum region and upper neck lesions: technique modification

A modification of the stereotactic radiosurgical procedure to permit treatment of lesions in the foramen magnum and upper cervical regions is described. The modification consists of placing the frontal pins of the stereotactic head ring in the zigoma bone, with no changes in the position of the occipital pins, so the final BRW head ring is oblique to the orbito-meatal plane. In this new position there is room enough in the posterior part of the guide for the support scrubs. This is unhampered by the patient's shoulders and the lesion is far enough to permit setting the axial coordinate sufficiently above the head ring plane.

Continuous intracerebroventricular infusion of dopamine and dopamine agonists through a totally implanted drug delivery system in animal models of Parkinson's disease

We studied the effect of intracerebroventricular infusion of dopamine and dopamine agonists in rat and primate models of Parkinson's disease as an experimental approach to the treatment of levodopa-induced fluctuations. The infusion of dopamine, lisuride, and pergolide into the ventricle ipsilateral to the lesion, by 6-hydroxydopamine, of the nigrostriatal pathway induced a contralateral rotation which was maximal 24-48 h after infusion and whose intensity progressively decreased over the period of 1 week. [3H]Spiperone binding was decreased by the infusion of dopamine but the responses to subcutaneous apomomorphine were unchanged. The infusion of dopamine also restored the levels of monoamines in the rat brain. In chronic reserpized rats, the infusion of dopamine restored brain levels of dopamine but did not reverse akinesia unless monoamine oxidase inhibitors were simultaneously administered, either systemically or intracerebroventricularly. Lisuride and pergolide proved much weaker than dopamine in reversing the effects of reserpine. Intracerebroventricular infusion of dopamine plus deprenyl reversed MPTP induced akinesia in monkeys but the pump used for the delivery was not well tolerated, because of its size, by the animals.