Effects of elephant garlic volatile oil (Allium ampeloprasum) and T-2 toxin on murine skin.

Effects of elephant garlic (Allium ampeloprasum) volatile oil (GVO) and trichothecene (T-2) toxin were studied in Swiss albino mice. The animals were 1) topically applied GVO, 2) topically applied T-2 toxin, 3) topically applied GVO followed by T-2 toxin (GVO/T-2), and 4) T-2 toxin application followed by GVO (T-2/GVO) on the right footpad. All animals were observed by Langerhans cell enumeration and pathological changes of the footpad on days 1, 3, 5 and 7. The number of Langerhans cells in the GVO treated group (1,097 +/- 33/mm2 to 1,624 +/- 19/mm2) was not significantly different when compared with the corresponding control left footpad (1,143 +/- 33/mm2 to 1,674 +/- 21/mm2). Langerhans cells density in T-2 toxin treated group (629 +/- 29/mm2to 1,090 +/- 31/mm2) was reduced by 20-35% of the opposite control footpad (962 +/- 40/mm2 to 1,392 +/- 29/mm2). Furthermore, GVO/T-2 and T-2/GVO treated mice showed a decrease in Langerhans cell number than a single T-2 toxin treated group. While Langerhans cells in T-2 toxin, GVO/T-2 and T-2/GVO groups revealed a smaller cell size with shortening dendritic processes when compare to the normal control group. Histopathological findings of the footpad skin in T-2 toxin treated group revealed epidermal desquamation and necrosis with edema and inflammatory cells infiltration. While GVO/T-2 and T-2/GVO showed a similar sequence but a lesser severe degree. These findings suggested that GVO both in pre- and posttreatment could protect T-2 toxin induced epidermal damage in a mouse footpad.

Promotion of aflatoxin B1-induced hepatocarcinogenesis by dichlorodiphenyl trichloroethane (DDT).

A study of the effect in rats of dichlorodiphenyl trichloroethane (DDT) on hepatocarcinogenesis that is initated by aflatoxin B1 (AFB1). In the first experiment, Buffalo rats were given a single oral dose of AFB1 (5 mg/kg) followed by dietary DDT (100 ppm) for 20 weeks. Neoplastic nodules were observed in 1 of the 14 AFB1-exposed rats, compared with 3 of the 19 rats in the AFB1/DDT group. In the second experiment, Wistar rats were given dietary aflatoxin B, (4 ppm) for 6 weeks followed by a 6-week exposure to DDT (500 ppm) in a plain semisynthetic diet. Five altered hepatic foci were displayed by seven rats in the AFB1 group, compared with 6 foci and one neoplastic focus in five of the AFB1/DDT rats at 32 weeks. Subsequently, the AFB1 group produced 8 (27.5%) tumor-bearing rats while 10 of the 28 (35.7%) AFB1/DDT-exposed rats were tumor-bearing by 60 weeks. The results suggest that DDT slightly potentiates hepatocarcinogenesis induced by either a single dose of AFB1 or short term-dietary AFB1.

Chimeric dengue type 2/type 1 viruses induce immune responses in cynomolgus monkeys.

Chimeric dengue type 2/type 1 (DEN2/1) viruses, which contain the structural genes of the dengue-1 (16007) parental virus and the nonstructural genes of the DEN2-PDK53 virus, have been constructed. These DEN2/1 viruses induce high levels of DEN1 virus-specific neutralizing antibodies in mice. In this study, the DEN2/1 viruses induced DEN1 virus-specific neutralizing antibodies without the development of viremia in cynomolgus monkeys. Dengue virus-specific IgM antibodies were detected in the sera of the immunized animals as early as 3 days post-immunization. After challenge with the DEN1-16007 wild-type virus, only a low level of viremia was detected in chimeric DEN2/1 virus-immunized monkeys. A second challenge, with DEN2-16681 virus, was given while the levels of DEN2-specific neutralizing antibodies were very low: infectious Dengue 2 virus could not be detected in sera of the monkeys. A correlation between the level of neutralizing antibody and the incidence of viremia could not be found. In addition, there was no significant increase in the levels of interferon gamma and soluble interleukin 2 receptor in the sera of the challenged monkeys, which suggests a reduction in immunopathogenesis caused by T-cell activation. Our findings suggest that DEN2/1 viruses may used as a live-attenuated candidate vaccine because of their safety, broad immunogenicity, and lower immunopathogenicity.