In previous papers, we showed that Ginkgo biloba extract (GBE) induced hepatic cytochrome P450 (CYP) activity, in particular pentoxyresorufin O-dealkylase (PROD; corresponding to CYP2B type) in rats, and that GBE influenced the efficacy of co-administered drugs. In this study, to clarify the nature of the induction, we examined the effects of GBE samples from different sources and some major constituents of GBE on rat hepatic CYP in vitro and in vivo. In the study in vitro, eight GBE samples dose-dependently inhibited PROD activity in microsomes prepared from GBE-treated rats, and the inhibitory ratio correlated well with the content of proanthocyanidin in the GBE samples. Moreover, among six GBE constituents examined, proanthocyanidin markedly inhibited the PROD activity. However, administration of two GBE extracts with different proanthocyanidin contents to rats induced hepatic CYP activity, including PROD, to similar extents, and proanthocyanidin alone did not induce PROD activity. Furthermore, GBE samples extracted with both acetone-water and ethanol-water showed similar induction of CYPs in rats in vivo. These results suggest that most GBE samples available in Japan induce CYPs in rats regardless of the preparation method of the GBE, and that proanthocyanidin is not responsible for the induction. Further studies will be necessary to identify the constituent(s) of GBE involved in the induction of CYPs in vivo.

Although prostate cancer patients with metastatic lesion initially respond to androgen ablation therapy, almost patients develop to hormone-refractory states. The optimal treatment for men with hormone refractory prostate cancer (HRPC) has not been established. Docetaxel is a semisynthetic taxane that inhibit tumor growth by induction of microtubule stabilization and promotion of bcl-2 inactivation, which induce apoptosis. Docetaxel as single agent has significant anti-tumor effect in HRPC patients. Docetaxel combined with estramustine or other antimicrotubular agents have shown further significant cytotoxicity in HRPC patients. In the United States, Food and Drug Administration (FDA) approved docetaxel, injection in combination with prednisone for the treatment of patients with advanced metastatic prostate cancer in 2004.

Photobacterium leiognathi cultured in marine broth emits a luminescence that is temporarily enhanced and then extinguished by glucose. Glucose reduces the luciferase level and the expression of lux ABG mRNA in P. leiognathi. The amount of ATP in P. leiognathi is temporarily increased and then declines to the normal level. These results indicate that the extinguishing by glucose in P. leiognathi is induced by the interruption of the translation of luciferase.

Susceptibility testing of 288 clinical isolates of P. aeruginosa in 2000 was performed by the disk diffusion method with observation at regular time course. Detailed analysis of the shape of the zones of inhibition gave interesting results, i.e. double zone of inhibition was found in MEPM specifically, unlike BIPM and IPM. The incidence was 50%. Moreover same phenomenon was detected in CAZ. After analyzing this phenomenon from the results of short-time-killing curve and inducibility of AmpC beta-lactamase it seems that there is a close relationship between formation of double zone of inhibition and bactericidal activity in sub-MIC drug concentration.

Two types of specific anti-influenza virus drugs are available in Japan; amantadine and neuraminidase inhibitors(zanamivir and osertamivir). Because of emerging of drug-resistant viruses, we have to develop new types of antiviral reagents. New type anti-influenza virus reagents are developed against viral specific growth steps other than M2 ion channel or NA. Cleavage and activation, attachment, and fusion steps are unique to HA. Transcription initiation step is unique to the viral RNA polymerase. The capped short RNA inhibited the viral RNA polymerase. The peptide derived from matrix protein inhibited the RNA polymerase activity. Antisense oligonucleotide, DNA enzyme and RNAi are also available to inhibit gene expression of influenza virus.

The in vivo metabolism of 2,3,3',4,4'-pentachlorobiphenyl (CB105) was studied in hamsters and the effect of cytochrome P450 inducers, phenobarbital (PB) and 3-methylcholanthrene (MC) on its metabolism was compared to rats. After administration of CB105 intraperitoneally at a dose of 3 mg/body, four metabolites, named M-1, M-2, M-3 and M-4, were detected in 5 days-feces of all groups and the formation ratio of the metabolites M-1-M-4 was 1:39:84:0.2 in untreated hamsters and 1:19:6.7:0.7 in untreated rats. On the basis of the mass spectra of four synthetic authentic compounds and the retention times on DB-1 and MPS50 columns, M-1, M-2, M-3 and M-4 were identified as 4'-hydroxy-2,3,3',4,5'-PenCB, 5'-hydroxy-CB105, 5-hydroxy-CB105 and 4-hydroxy-2,3,3',4',5-PenCB, respectively. The pretreatment of PB and MC resulted in about 2-fold fecal excretion of four metabolites in hamsters and in about 3-fold in rats. Of four metabolites, only M-4 were detected in the serum at 5 days after CB105 administration and the concentration was 0.39 microgram/ml of hamster serum and 0.28 microgram/ml of rat serum. In hamsters, the concentration of M-4 was increased to 1.8-fold of untreated animals by PB treatment and 2.6-fold by MC treatment. On the other hand, the treatment of rats with PB and MC did not show such an increase of serum M-4. These results suggested that the hamster oxidized 2,3,4-trichloro-substituted benzene ring predominantly rather than 3',4'-dichloro-substituted benzene ring differently from the rat and that M-4 formed in hamster liver distributed to the blood and retained there to a considerable extent in comparison with that formed in rat liver.

Two different mechanisms have been well known to regulate the amounts of various transcripts in response to internal and external environmental stimuli. First, by binding of activated transcription factors to DNA regulatory regions including the cAMP response element, hormone response element, and activator protein-1 region upstream in various genes, the rate of transcription from DNA to mRNA is regulated. Secondly, the degradation of some mRNAs related to immune responses has been reported to be regulated by binding of RNA-binding proteins to adenylate uridylate-rich elements (AU-rich elements, AREs) located in the 3'-untranslated region (3'-UTR). The original study identifying the existence of a common regulatory nucleotide sequence in the 3'-UTR of inflammatory mediator transcripts pointed out that the AREs are characteristic of immune-related functional proteins. The number of transcripts containing AREs in the 3'-UTR has increased and several neuronal proteins including beta 2-adrenergic receptor, nerve growth factor, tyrosine hydroxylase, and nitric-oxide synthase II, have been reported to have AREs. We here reviewed the recent advances in the neuropsychopharmacological understanding of post-transcriptional regulation by RNA-binding protein and also pointed out the importance of this regulation in future studies using various stress paradigms.

G-protein coupled receptor(GPCR) agonists are well-known inducers of cardiac hypertrophy. We found that the shedding of HB-EGF via metalloproteinase activation and subsequent transactivation of the epidermal growth factor receptor occurred when cardiomyocytes were stimulated by GPCR agonists, leading to cardiac hypertrophy. A new inhibitor of HB-EGF shedding, KB-R7785, blocked this signaling. We cloned a disintegrin and metalloprotease 12(ADAM12) as a specific enzyme to shed HB-EGF in the heart and found that dominant negative expression of ADAM12 abrogated this signaling. KB-R7785 bound directly to ADAM12, suggesting that inhibition of ADAM12 blocked the shedding of HB-EGF. In mice with cardiac hypertrophy, KB-R7785 inhibited the shedding of HB-EGF and attenuated hypertrophic changes. These data suggest that shedding of HB-EGF by ADAM12 plays an important role in cardiac hypertrophy, and that inhibition of HB-EGF shedding could be a potent therapeutic strategy for cardiac hypertrophy.