Impact of minimal tumor burden on antibody response to vaccination.

Four randomized phase III trials conducted recently in melanoma patients in the adjuvant setting have been based in part on the correlation between antibody responses in immunized patients and improved survival. Each of these randomized trials demonstrated no clinical benefit, although again there was a significant correlation between antibody response after vaccination and disease free and overall survival. To better understand this paradox, we established a surgical adjuvant model targeting GD2 ganglioside on EL4 lymphoma cells injected into the foot pad followed by amputation at variable intervals.

Limited effect of CpG ODN in preventing type 1 diabetes in NOD mice.

Type 1 diabetes is considered as Th1 cell mediated autoimmune disease and the suppression of Th1 cells or the activation of Th2 cells has been regarded as a plausible immunologic intervention for the prevention of type 1 diabetogenesis in a rodent model. CpG ODN is an immunostimulatory sequence primarily present in bacterial DNA, viral DNA and BCG. CpG ODN is conventionally classified as a Th1 cell activator, which has been clinically applied to cancer, allergy and infectious disease.

In vitro antibacterial activity of echinomycin and a novel analogue, YK2000, against vancomycin-resistant enterococci.

The in vitro inhibitory and bactericidal activity of echinomycin and its the novel synthetic analogues of echinomycin,YK2000 and YK2005, were evaluated using 93 clinical isolates of vancomycin-resistant enterococci (VRE). In agar dilution tests, the MIC(90) of echinomycin and YK2000 were 0.125 and 8 mg/l, respectively, using Mueller-Hinton II agar, while that of YK2005 was 32 mg/l.

Susceptibility of several strains of mice to Echinostoma hortense infection.

Susceptibilities of 5 different mice strains, including C3H/HeN, BALB/c, C57BL6, FvB and ICR, to Echinostoma hortense infection, was evaluated. The worm expulsion rate, worm size and egg production were observed from 1 to 8 weeks after infection with 30 metacercariae. C3H/HeN and ICR mice showed the highest worm maturation rates.

Echinomycin and a novel analogue induce apoptosis of HT-29 cells via the activation of MAP kinases pathway.

Echinomycin, in typical DNA minor groove binder, had comparable efficacy compared to 5-FU in the phase II trail of colon cancer treatment. To improve echinomycin's drawback (hydrophobicity, toxicity), we synthesized the YK-2000 series (echinomycin analogues). Among these, YK-2000 had the best in vitro cytotoxicity on six different human solid cancer cell lines.

Synthesis and biological activity of new quinoxaline antibiotics of echinomycin analogues.

Novel quinoxaline antibiotics having the methylenedithioether bridge as an analogue of echinomycin have been synthesized by insertion of methylene moiety between -S-S- bond. The compound 1a shows remarkable cytotoxicities against human tumor various cell lines, and is active VRE (vancomycin-resistant enterococci) within MIC range 0.5-8 microg/mL.

Antitumor activity of novel deoxoartemisinin monomers, dimers, and trimer.

The first primary amines 9 and bromoalkyl analogues 7 of deoxoartemisinin with nonacetal functionality at C-12 are prepared as versatile intermediates for the synthesis of various derivatives. Eight C-12 nonacetal type dimers and one trimer of deoxoartemisinin were prepared using novel chemistry. Dimers, particularly 12a, 18a,b, and trimer 17, were especially potent and selective at inhibiting the growth of certain human cancer cell lines and were comparable to that of clinically used anticancer drugs.