Use of color power transcranial Doppler sonography to monitor aneurysmal coiling.

We describe the use of a recently developed technique in the field of color Doppler sonography, called power Doppler or color Doppler energy, that produces better images of the intracranial arteries than those obtained by conventional color Doppler techniques. Color Doppler energy makes it possible to identify aneurysms and their relationship to the parent artery, thus allowing one to observe how much of an aneurysm remains patent and the condition of adjacent arteries during endovascular treatment. We describe the use of this technique during the insertion of Guglielmi detachable coils into aneurysms and during subsequent follow-up examination.

Color transcranial "power" Doppler ultrasound of intracranial aneurysms.

"Color Doppler energy" (or "power Doppler"), a new color Doppler ultrasound technique that is independent of flow direction and very sensitive to movement, was assessed for its use in the identification of intracranial aneurysms in patients with recent subarachnoid hemorrhage immediately prior to using cerebral angiography. Features that identified aneurysms using this technique included the appearance of abnormal color where no normal artery was expected, abnormal bulging of an artery, and greater "expansibility" of the aneurysm in comparison to an adjacent normal vessel. In this exploratory study, 30 of 33 aneurysms were correctly identified in 35 patients with a good bone window. Color Doppler energy is considerably more sensitive to intracranial blood flow than conventional color Doppler imaging. Color Doppler energy is a useful research tool; if these preliminary results are verified in larger series, in addition to examination for vasospasm, the technique could be used for identification and follow up of aneurysms.

Vecuronium in alcoholic liver disease: a pharmacokinetic and pharmacodynamic analysis.

To determine the effect of alcoholic liver disease on the pharmacokinetics and pharmacodynamics of vecuronium, the authors administered vecuronium 0.1 mg.kg-1 iv to ten surgical patients with alcoholic liver disease and ten healthy surgical patients. All patients were anesthetized with nitrous oxide and isoflurane. We recorded and quantitated the force of thumb adduction in response to supramaximal ulnar nerve stimulation. Plasma concentrations of vecuronium and its 3-desacetyl metabolite were determined by a capillary gas chromatography assay. Only the time to attain 100% twitch depression (onset time) was prolonged in liver disease patients (2.8 +/- 0.7 min; mean +/- SD) as compared to control patients (1.9 +/- 0.4 min). The time from vecuronium administration to recovery of twitch tension was unaffected by alcoholic liver disease. The time to the reappearance of twitch response was 32.7 +/- 9.7 min in patients with liver disease and 36.8 +/- 15.5 min in controls. Plasma concentration-time data were fit to a two-compartment model. Vecuronium clearance, steady-state volume of distribution, and elimination half-time were unchanged by alcoholic liver disease. The authors conclude that alcoholic liver disease does not affect the pharmacokinetics or duration of action of vecuronium when an intravenous bolus dose of 0.1 mg.kg-1 is administered.

Nonequivalence of the metal binding sites in vanadyl-labeled human serum transferrin.

Vanadyl ion, VO(IV), has been used as an electron paramagnetic resonance (EPR) spin label to study the metal-binding properties of human serum transferrin in the presence of bicarbonate. Iron-saturated transferrin does not bind the vanadyl ion. Room temperature titrations of apotransferrin with VO(IV) as monitored by EPR indicate the extent of binding to be pH dependent, with a full 0.2 VO(IV) ions per transferrin molecule bound at pH 7.5 and 9, but only about 1.2 VO(IV) ions bound at pH 6. The EPR spectra of frozen solutions with or without 0.1 M NaCUO4 at 77 K show that there are two spectroscopically nonequivalent binding sites (A and B) with a slight difference in binding constants. One site (A site) exhibits essentially constant binding capacity in the pH range 6-9, but the other (B site) becomes less avialable as the pH is reduced below 7. Results with mixed Fe(III)-VO(IV) transferrin complexes suggest that iron shows a slight tendency to bind at the B site over the A site pH 7.5 and 9.0. Only the B site in both vanadyl and iron transferrins is perturbed by the presence of perchlorate.