Takashi Ono

Stimulation of biosynthesis of nerve growth factor by acidic fibroblast growth factor in cultured mouse astrocytes

Bovine acidic and basic fibroblast growth factors (aFGF and bFGF) dose-dependently stimulated the release of nerve growth factor (NGF) in a culture medium of mouse astrocytes. The NGF concentration in the medium started to increase compared to that of the control cultures 4 h later and was further sustained for 24 h when aFGF was contained. The content of NGF mRNA in the astrocytes treated with aFGF peaked at eightfold over the control level after 4 h. The astrocytes did not proliferate until after 72 h when treated with FGFs under the conditions employed. These results indicate that aFGF stimulates the biosynthesis of NGF in cultured astrocytes without promoting cell proliferation.

Meloxicam ameliorates motor dysfunction and dopaminergic neurodegeneration by maintaining Akt-signaling in a mouse Parkinson's disease model.

A series of oxicam non-steroidal anti-inflammatory drugs (NSAIDs) have been shown to be neuroprotective against 1-methyl-4-phenyl pyridinium in human neuroblastoma SH-SY5Y cells via the phosphatidylinositol 3-kinase (PI3K)/Akt pathway independent of cyclooxygenase (COX) inhibition. The present study endeavored to establish this novel effect of meloxicam (MLX), an oxicam NSAID, in a mouse Parkinsons disease (PD) model using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Male C57BL/6 mice, which received MPTP (30 mg/kg/day; s.c.) for 5 consecutive days (chronic model) with 10-day follow-up saline administrations, showed significant motor dysfunction in the pole test due to reduced tyrosine hydroxylase (TH) protein levels in the brain on day 16 after MPTP/saline treatment. Daily coadministrations of MLX (10mg/kg/day; i.p.) and MPTP for the first 5 days and follow-up 10 days with MLX administrations alone (MPTP/MLX treatment) significantly ameliorated MPTP-induced behavioral abnormalities in mice. Concomitant decreases of TH protein levels in the striatum and midbrain of MPTP/MLX-treated mice were not only significantly (p<0.01 and p<0.05, respectively) ameliorated but phosphorylated Akt (pAkt473) expression in the midbrain was also significantly (p<0.01) increased in the midbrain when compared with MPTP/saline-treated mice. These results suggest that MLX, an oxicam NSAID, attenuated dopaminergic neuronal death in the experimental MPTP-PD model by maintenance of the Akt-signaling. Oxicam NSAIDs may serve as potential drugs for PD treatment via a novel mechanism of action.

Cell kill kinetics of an antineoplastic nucleoside, 1-(2-deoxy-2-methylene-β-d-erythro-pentofuranosyl)cytosine

The cytotoxic properties of 1-(2-deoxy-2-methylene-beta-D-erythro-pentofuranosyl)cytosine (DMDC) were compared with those of 1-beta-D-arabinofuranosylcytosine (ara-C), using SK-MEL-28(P-36) human melanoma cells. DMDC and ara-C were most cytotoxic to cells in the S phase of the cell cycle. Cell cycle progression in S phase was blocked by both compounds. Treatment with DMDC (1 microgram/mL) or ara-C (1 and 30 micrograms/mL) did not increase cytotoxicity against asynchronous cells when the exposure time was prolonged from 1 to 6 hr, but did increase cytotoxicity thereafter. These findings suggest that cells in S phase are rapidly killed by the treatment but are temporarily prevented or delayed entry into the drug-sensitive S phase. On the other hand, DMDC treatment at a higher concentration (30 micrograms/mL) increased cytotoxicity in a time-dependent manner. Intracellular DMDC 5-triphosphate (DMDCTP) increased in proportion to exogenous DMDC concentration, which was not saturated by treatment with a maximum concentration of the compound at 80 micrograms/mL. In contrast, intracellular ara-C 5-triphosphate reached peak level when the cells were treated with ara-C at 8 micrograms/mL. The cytotoxicity of DMDC treatment for 4 hr increased relative to the intracellular DMDCTP accumulated during the period. These findings suggest that in cells treated with DMDC at a high concentration, an effective DMDCTP level is maintained for an extended period after washing out the compound from the medium. Consequently, the cells would be killed in the same way as in the case of extended exposures over 6 hr to DMDC at low concentration or to ara-C, in addition to acute S-phase-specific cytotoxicity.

Detection of landiolol using high-performance liquid chromatography/fluorescence: A blood esterase-sensitive ultra-short-acting β1-receptor antagonist

Landiolol hydrochloride, a new adrenergic beta(1)-selective antagonist having an ultra-short half-life, is used to prevent tachyarrhythmia during surgery. Since landiolol is thought to be rapidly hydrolyzed to an inactivate metabolite by esterases, quantification of the drug concentration in the blood is impractical. The landiolol concentration in blood was halved within 5 min after blood sampling. This degradation was effectively prevented by pre-treatment with neostigmine (100 microg) in the sampling tube, but not by EDTA pre-treatment, indicating that landiolol could be metabolized by pseudocholinesterase in plasma. After the one-step solid-phase extraction, fluorescence detection of landiolol reduced chromatographic background signals and then improved assay sensitivity to the lower limit of 10 ng/ml in blood; this reproducible approach yielded coefficient variation of less than 6%. The blood concentration-time profile of landiolol hydrochloride in patients of the present investigation afforded more practical assessment than previously reported studies, thus improving accuracy and facilitating detailed pharmacokinetic study in relation to the pharmacological action of drug.