Absorption of glucosamine is improved by considering circadian rhythm and feeding time in rats.

Although many basic and clinical studies have shown that glucosamine (GlcN) improves osteoarthritis, it has not been widely used in the clinic because its bioavailability is only 6%. We investigated the influence of dosing-time factors, which influence pharmacokinetics and food intake in rats to improve its bioavailability. When GlcN was orally administered to rats housed under conditions of free access to food for 12 h or fasting conditions, no significant differences in GlcN concentration were observed in the rat plasma between the two groups.

Chronopharmacology of mizoribine in collagen-induced arthritis rats.

We previously reported that higher therapeutic effects were obtained in rheumatoid arthritis (RA) patients and RA model animals when the dosing-times of methotrexate and tacrolimus were chosen according to the 24-h rhythms of the inflammatory response. Mizoribine (MZR) is an immunosuppressive agent and is used against RA in the same manner as methotrexate and tacrolimus. In this study, we examined whether a dosing-time dependency of the therapeutic effect of MZR could be detected in collagen-induced arthritis (CIA) rats.

Dosing time-dependency of the arthritis-inhibiting effect of tacrolimus in mice.

Stiffness and cytokine in blood levels show 24-h rhythms in rheumatoid arthritis (RA) patients. We previously revealed that higher therapeutic effects were obtained in RA patients and RA model animals when the dosing time of methotrexate was chosen according to the 24-h rhythms to cytokine. In this study, we examined whether a dosing time-dependency of the therapeutic effect of tacrolimus (TAC) could be detected in collagen-induced arthritis (CIA) and MRL/lpr mice.

Methotrexate chronotherapy is effective against rheumatoid arthritis.

Methotrexate (MTX) is the most important drug for treating rheumatoid arthritis (RA). It has been stated that cytokines play an important role in the pathogenesis of RA, and that cytokine levels increase and show 24-h rhythms in RA patients. Previously, we found that arthritis was relieved after the administration of MTX at specific times in synchronization with the 24-h rhythm of tumor necrosis factor (TNF)-α in collagen-induced arthritis (CIA) animals.

Mechanism of the cardioprotective effects of docetaxel pre-administration against adriamycin-induced cardiotoxicity.

We revealed that pre-treatment with docetaxel (DOC) 12 h before adriamycin (ADR) administration significantly reduced ADR-induced toxic death compared with the simultaneous dosing schedule that was commonly used in previous studies. We considered that pre-treatment with DOC relieves ADR-induced cardiotoxicity. In this study, we investigated the influence of DOC on the pharmacokinetics and pharmacodynamics of ADR in order to clarify the mechanism by which DOC pre-treatment relieves ADR-induced cardiotoxicity.

A toxicoproteomic study on cardioprotective effects of pre-administration of docetaxel in a mouse model of adriamycin-induced cardiotoxicity.

Studies suggest that pre-administration of docetaxel (DOC) in adriamycin (ADR)-DOC combination anticancer therapy results in stronger antitumor effects and fewer ADR-induced cardiotoxic deaths in mouse model, yet no mechanism explaining this effect has been established. The aim of this study was to identify cellular processes in mouse heart tissue affected by different ADR/DOC dosing protocols using a toxicoproteomic approach. We applied fluorogenic derivatization-liquid chromatography-tandem mass spectrometry (FD-LC-MS/MS) - which consists of fluorogenic derivatization, separation and fluorescence detection by LC, and identification by LC-tandem mass spectrometry - to the proteomic analysis of heart tissue from control, intermittent-dosing (DOC-ADR), and simultaneous-dosing (ADR&DOC) groups.

Therapeutic index of methotrexate depends on circadian cycling of tumour necrosis factor-alpha in collagen-induced arthritic rats and mice.

Objectives: Rheumatoid arthritis is an autoimmune disorder of unknown aetiology. Morning stiffness, a characteristic feature of rheumatoid arthritis, shows a 24-h rhythm. Noticing this rhythm, we hypothesized the presence of a similar rhythm for a rheumatoid arthritis indicator, in addition to dosing-time dependency of the anti-rheumatic effect of methotrexate in arthritis induced by collagen in rats and mice, which reflect the symptomatology of rheumatoid arthritis patients.

Pre-administration of docetaxel protects against adriamycin-induced cardiotoxicity.

Background: We have revealed in a pre-clinical study that the combination of adriamycin (ADR) and docetaxel (DOC) in which ADR was administered 12 h after DOC injection not only significantly reduced leukopenia and toxic death but also significantly increased the antitumor effect compared with the dosing schedule without an interval between each injection used commonly in clinical practice. The purpose of this study was to clarify in mice whether the toxic death caused by ADR was reduced by administering ADR after DOC injection when the doses and dosing-interval of ADR and DOC were changed.

Methods: ADR alone or a combination of ADR and DOC (ADR/DOC group in which both drugs were administered simultaneously or DOC-ADR group in which ADR was administered after DOC injection) was administered every 7 days in mice.