Evaluation of pelvic floor muscular redistribution after primary closure of classic bladder exstrophy by 3-dimensional magnetic resonance imaging.

PURPOSE: We used 3-dimensional magnetic resonance imaging reconstruction to generate models of the pelvic floor musculature in classic bladder exstrophy, allowing for statistical analysis of changes seen in the anatomy after primary closure. MATERIALS AND METHODS: Patients with classic bladder exstrophy underwent pelvic magnetic resonance imaging before and after primary closure. Contours of the levator ani were mapped and measured in 3-dimensional space. In addition, 2-dimensional angles and measurements were used to make a quantitative and qualitative analysis of the pelvic floor before and after closure. RESULTS: A total of 19 cases of classic bladder exstrophy were included in the study, with 12 closed as newborns without osteotomy and 7 closed later with osteotomy. In both groups the pre-closure exstrophy pelvic floor in the axial plane was box-like and after closure it had a more inward rotation. The steepness and angulation of the levator ani muscle remained relatively unchanged in both groups. The levator ani muscle group, with and without osteotomy, was redistributed into the anterior compartment of the pelvis after closure. Postoperatively a successfully closed exstrophy had the bladder positioned deeply within the pelvis. After closure the levator ani muscle regained the expected smooth contoured shape. CONCLUSIONS: Primary closure of bladder exstrophy 1) reshapes the pelvis from a box-like configuration to a more inwardly rotated hammock, 2) redistributes a significant portion of the levator ani muscle into the anterior compartment and 3) facilitates a smooth uniform contouring to the pelvic floor. Closing the bony pelvic ring by pubic reapproximation in the newborn or by osteotomy in an infant produces similar changes in the pelvic floor.

Impurity profile tracking for active pharmaceutical ingredients: case reports.

Tracking the impurity profile of an active pharmaceutical ingredient (API) is a very important task for all stages of drug development. A systematic approach for tracking impurity profile of API is described. Various real pharmaceutical applications are presented through successful examples of impurity profile tracking for three different novel APIs. These include MK-0969, an M3 antagonist; MK-0677, an oral-active growth hormone secretagogue and API-A, a cathepsin K inhibitor. A general strategy including selection of a reversed phase high performance liquid chromatographic (RP-HPLC) impurity profile method based on screening various stationary phases and changing the pH of the mobile phase and elucidation of impurity structures through the utilization of LC-MS, preparative-LC and NMR is demonstrated. A series of studies were conducted on the peak purity check by using the LC-UV diode-array and LC-MS detections. The advantages and disadvantages of each technique in the evaluation of peak purity are discussed.

Production of GABA by cultured hippocampal glial cells.

Medium conditioned by cultured hippocampal glial contains an inhibitory factor that can hyperpolarize and suppress neuronal activity. Using biochemistry, electrophysiology, pharmacology, and mass spectrometry, we have identified the inhibitory factor as GABA (gamma-aminobutyric acid). Like GABA, the inhibitory factor increases chloride and potassium currents in neurons, which can be blocked by bicuculline. Mass spectrometry analysis of conditioned medium reveals peaks that are identical to that for GABA. Up to 500 micromolar GABA is found in conditioned medium from glial cultures. No GABA is found in conditioned medium from neuronal cultures. Hippocampal glia make much more GABA than cortical glia or glia from other brain regions. It is not clear how hippocampal glia synthesize GABA. Although they express GAD mRNA and adding glutamate to the culture medium increases the amount of GABA produced, other data suggest that glia do not use GAD to make GABA. Identifying the mechanism(s) by which GABA is produced by hippocampal glia would help clarify its role in modulating neuronal activity in the brain.

Investigations into the chromatographic behavior of a doxorubicin-peptide conjugate.

HPLC impurity profile method development for a doxorubicin-heptapeptide conjugate included significant changes of the separation profile with diluent, eluent and pH. These separation variables were also temperature-dependent with a shift in retention from 35 to 45 degrees C. There was also a direct relationship of temperature with LC retention, and a pH minimum at 5.9. Atypical dependence of the impurity profile on diluent at a k' of 18 led to further investigation. A large change in retention by several minutes was a function of both the organic eluent composition and temperature between 15 and 30 degrees C. Several Van't Hoff temperature studies from 5 to 65 degrees C on several column types resulted in non-linear plots. Analysis of the molecular subunits suggested that the peptide portion of the analyte influenced the non-linear retention behavior. The stationary phase type was not a significant factor causing non-linearity. Circular dichroism-temperature studies indicated a notable transition in ellipticity for the amine regions (198-202 nm) that occurred between 39 and 44 degrees C. This transition temperature range coincided with the results of the Van't Hoff analysis, between 35 and 44 degrees C, to indicate that these effects were not primarily stationary phase induced.