Multiple cellular phenotypes in an insertional mutation in mouse affecting bone development.

The 6093 line of transgenic mice exhibits altered bone development as a result of an insertional mutation by the transgene. Female transgenic mice show a marked kyphosis as early as 2 weeks of age. Vertebrae from female mice have lower total bone area and mineral content than age-matched, gender-matched controls, although the bone mineral density is not changed. The femur and tibia exhibit the opposite effect-increased bone area and mineral content. Fluorescent bone label experiments indicated an increased rate of bone mineral deposition in the femur during the early postnatal growth period, and bone marrow from femurs of 6093 females had increased numbers of fibroblast colony-forming units. Transgenic females also are obese and have altered thymocyte development, suggesting that the insertional mutation affects multiple cell populations. We hypothesize that these phenotypes arise as a result of an alteration in the function or developmental potential of a stromal cell or mesenchymal stem cell.

Validation and application of an immunoradiometric assay for the determination of human parathyroid hormone fragment 1-34 in dog plasma following subcutaneous and intravenous administration.

A method for the measurement of human parathyroid hormone fragment 1-34 (PTH1-34) in dog plasma was developed by modification of a commercially available immunodiometric assay (IRMA) designed for the determination of rat PTH1-34 in serum. Major modifications were made to the assay in order to circumvent significant problems encountered during the validation of the IRMA. PTH1-34 was found to be highly unstable in both rat serum and dog serum and plasma at room temperature, in contrast to literature reports. The addition of a protease inhibitor cocktail to serum or plasma samples was necessary to prevent in-vitro proteolytic degradation of human PTH1-34 prior to analysis. Additionally, plasma was chosen over serum as the sample matrix to expedite the separation of samples from cells, minimizing proteolytic degradation prior to the addition of cocktail. Finally, the reported 100% cross-reactivity between rat and human PTH1-34 was found to be only 65%; therefore, a human PTH1-34 standard was substituted for the rat standard. These modifications allowed the accurate measurement of human PTH1-34 in plasma obtained from dogs dosed intravenously and subcutaneously with human PTH1-34 using a commercially available kit.

Anti-inflammatory pharmacology and mechanism of the orally active capsaicin analogs, NE-19550 and NE-28345.

We have evaluated the properties of a new class of anti-inflammatory agents derived from capsaicin, using the analogs NE-19550 (N-vanillyloleamide) and NE-28345 (N-oleyl-homovanillamide) as examples. This class displayed an atypical profile in the assays utilized, including 1) anti-edema and antileukocyte migration activity in the rat carrageenan pleurisy assay without suppression of pleural prostanoid synthesis, 2) blockade of human platelet aggregation induced by arachidonate or PAF but not that induced by the PGH2 analog U-46619, without equivalent inhibition in vitro of mammalian cyclooxygenase or thromboxane synthetase preparations, 3) greater potency and efficacy in the rat implanted sponge assay than in the adjuvant arthritis assay, without inhibition of LTB4 or 15-HETE synthesis in vitro, 4) stronger topical activity in the mouse croton oil inflamed ear assay than the guinea pig UV erythema assay, and 5) oral activity in the rat carrageenan paw edema assay and mouse phenylquinone abdominal constriction rest combined with failure to induce gastric erosion in rats at therapeutic doses. We conclude that NE-19550 and NE-28345 do not act like conventional NSAIDs via suppression of arachidonic acid metabolism.