A feasibility study for measuring accurate tendon displacements using an audio-based Fourier analysis of pulsed-wave Doppler ultrasound signals.

The accuracy of Pulsed-Wave Doppler Ultrasound displacement measurements of a slow moving "tendon-like" string was investigated in this study. This was accomplished by estimating string displacements using an audio-based Fourier analysis of a Pulsed-Wave Doppler signal from a commercial ultrasound scanner. Our feasibility study showed that the proposed technique is much more accurate at estimating the actual string displacement in comparison to the scanner's onboard software. Furthermore, this study also shows that a real-time Doppler data acquisition from an ultrasound scanner is possible for the ultimate purpose of real-time biological tendon displacement monitoring.

Capillary electrophoresis-mass spectrometry for impurity profiling of basic pharmaceuticals using non-volatile background electrolytes.

A generic approach has been developed for coupling capillary electrophoresis (CE) using non-volatile background electrolytes (BGEs) with mass spectrometry (MS) using a sheath liquid interface. CE-MS has been applied for basic and bi-functional compounds using a BGE consisting of 100 mM of TRIS adjusted to pH 2.5 using phosphoric acid. A liquid sheath effect is observed which may influence the CZE separation and hence may complicate the correlation between CE-UV and CE-MS methods. The influence of the liquid sheath effect on the migration behavior of basic pharmaceuticals has been studied by simulation experiments, in which the BGE outlet vial is replaced by sheath liquid in a CE-UV experiment. As a consequence of the liquid sheath effect, phosphate based BGEs can be used without significant loss of MS sensitivity compared to volatile BGEs. The use of buffer constituents such as TRIS can lead to lower detection limits as loss of MS sensitivity can be compensated by better CE performance. TRIS based BGEs permit relatively high injection amounts of about 100 pmol while maintaining high resolution. The ESI-MS parameters were optimized for a generic method with maximum sensitivity and stable operation, in which the composition of the sheath liquid and the position of the capillary were found to be important. Furthermore, the nebulizing pressure strongly influenced the separation efficiency. The system showed stable performance for several days and a reproducibility of about 15% RSD in peak area has been obtained. Nearly all test compounds used in this study could be analyzed with an MS detection limit of 0.05% measured in scan mode using extracted ion chromatograms. As a result, CE-MS was found to be a valuable analytical tool for pharmaceutical impurity profiling.

Clinical experience using gabapentin adjunctively in patients with a history of mania or hypomania.

BACKGROUND: Gabapentin is an anticonvulsant proposed to have mood-stabilizing properties. It has been effective in the add-on treatment of refractory partial seizures and secondary generalized tonic-clonic seizures. It has the advantage of a favorable side effect profile and lack of drug interactions. METHODS: Twelve consecutive outpatients with persistent, treatment-resistant bipolar spectrum disorders were treated with gabapentin in combination with other medications. Patients were started at 300 mg/day, which was titrated according to clinical response. Response was assessed every 3-4 weeks with a Clinical Global Improvement Scale. Dosage and side effects were noted. The median peak dose was 2400 mg/day. RESULTS: One patient had a marked response to gabapentin; seven, a moderate response; two, mild; and two, no response to treatment. Six patients discontinued treatment due to somatic complaints (i.e., sedation or fatigue). The most frequently reported adverse effect was sedation. LIMITATIONS: Gabapentin was added openly, and rating was nonblind in this case series. The use of concomitant medications could have increased the amount of sedation experienced with gabapentin. CONCLUSION: Overall, gabapentin was associated with moderate improvement of mood symptoms. Given the severity and chronicity of these patients' illness, a moderate response must be considered a relative success. Controlled studies of gabapentin are needed to clarify its role in the treatment of bipolar disorder.