Systemic administration of monosodium glutamate elevates intramuscular glutamate levels and sensitizes rat masseter muscle afferent fibers.

There is evidence that elevated tissue concentrations of glutamate may contribute to pain and sensitivity in certain musculoskeletal pain conditions. In the present study, the food additive monosodium glutamate (MSG) was injected intravenously into rats to determine whether it could significantly elevate interstitial concentrations of glutamate in the masseter muscle and whether MSG administration could excite and/or sensitize slowly conducting masseter afferent fibers through N-methyl-D-aspartate (NMDA) receptor activation. The interstitial concentration of glutamate after systemic injection of isotonic phosphate-buffered saline (control) or MSG (10 and 50mg/kg) was measured with a glutamate-selective biosensor.

Identification and synthesis of norhydromorphone, and determination of antinociceptive activities in the rat formalin test.

The main objective of this paper is to report the identification and synthesis of norhydromorphone, a novel metabolite of hydromorphone, and its antinociceptive activities when tested in the formalin test as compared to other known analgesics. In addition, we are reporting for the first time the lack of antinociceptive activities of hydromorphone-3-glucuronide, dihydromorphine-3-glucuronide and dihydroisomorphine-3-glucuronide in the rat formalin test. Norhydromorphone was isolated and identified as a metabolite of hydromorphone in a cancer patient's urine.

Comparison between capillary electrophoresis and high-performance liquid chromatography for the stereoselective analysis of carvedilol in serum.

A high-performance liquid chromatographic (HPLC) assay using a chiral stationary phase was developed and validated for the determination of carvedilol enantiomers in human serum and was compared with a previously developed capillary electrophoresis (CE) method. The CE and the HPLC assay were compared by analyzing a series of serum samples containing racemic carvedilol in different concentrations using the two methods. The concentrations obtained by the two assays were not found to be significantly different indicating that CE and HPLC are comparable in terms of reproducibility and precision for the stereoselective analysis of carvedilol in human serum.

Comparison of Sulfadimethoxine Residue Analyses in Salmon Muscle Using HPLC and Charm II Test.

Sulfadimethoxine (SDM) residues in chinook salmon muscle were measured by high-performance liquid chromatography (HPLC) and the Charm II test to evaluate the efficacy of the Charm test for the measurement of sulfonamide residues in fish muscle. Both HPLC and Charm analyses were performed in the presence of salmon tissue matrix for the purpose of evaluating the results in field conditions. The sensitivity of the HPLC method was 0.