Hiroshi Ohtomo

Lethal efficacy of extract from Zingiber officinale (traditional Chinese medicine) or [6]-shogaol and [6]-gingerol in Anisakis larvae in vitro.

The authors previously reported that an extract fromZingiber officinale, traditionally eaten along with raw fish and used in traditional Chinese medicine, effectively destroyedAnisakis larvae in vitro. In this study, we analyzed the effective components of ginger rhizomes. Methanol extracts were fractionated after first being treated with HCl at pH 3, then with NaHCO3 at pH 10, and, finally, with NaOH at pH 13 (fraction 1). In general, this fraction is rich in neutral substances. [6]-Shogaol and [6]-gingerol, known neutral components of ginger rhizomes, were detected using gas chromatography and were found to be the most prevalent components in the fraction, occurring in quantities that resulted in a dose-dependent killing efficacy. Authentic [6]-shogaol and [6]-gingerol could killAnisakis larvae at a minimal effective dose of 62.5 and 250 μg/ml, respectively. However, the concentration of [6]-gingerol in fraction 1 was >20 times that of [6]-shogaol, making the former the most active component in the fraction. Furthermore, synergistic effects between [6]-gingerol and a small amount of [6]-shogaol were observed. Pyrantel pamoate, an available antinematodal drug, had no lethal effect, even at a concentration of 1 mg/ml. In saline solution containing [6]-shogaol (62.5 μg/ml), >90% of larvae lost spontaneous movement within 4 h and were destroyed completely within 16 h. Microscopical examinations showed destruction of the digestive tract and disturbances of cuticulae.

Reduced fecundity of Hymenolepis nana due to thymus-dependent immunological responses in mice

Abstract Reduced fecundity of Hymenolepis nana due to thymus-dependent immunological responses in mice. International Journal for Parasitology 16 : 81–85. The fecundity of the dwarf tapeworm, Hymenolepis nana , was enhanced in congenitally athymic nude CD-1 (ICR) mice but depressed to the same degree as in phenotypically normal littermates when they were reconstituted with thymocytes before infection. The reduction in fecundity of this parasite was clear only when H. nana were recovered from those strains of mice which demonstrate a “late response” against luminal cysticercoid challenge before the established worms become fully mature (within 15 days of initial immunizing egg inoculation). The fecundity of H. nana in dd mice, which acquire the late response within 30–40 days, was greatly advanced than that in BALB/c or CD-1 (ICR) mice and somewhat better than even that in the nude CD-1 (ICR) mice and appeared to be little, or not at all, depressed. The fecundity and longevity of this parasite, highly variable among mouse strains, is discussed in terms of variations in the rapidity of expression of protective immunity against the lumen phase.

Significance of blood urea nitrogen as an index of renal function in mice infected withPlasmodium berghei

Parameters of renal function were evaluated in severe malarial infection, using mice infected withPlasmodium berghei. When 7-week-old male BALB/c mice were inoculated with 1×107P. berghei NK65-infected red blood cells, the rodents died an average of 7.4 days after inoculation. Anemia developed on day 5 after inoculation and progressed markedly on days 6 and 7. Plasma urea nitrogen increased rapidly on day 6 or 7, after which death occurred within 24 h. In contrast, urinary urea nitrogen excretion decreased on the same day. Urinary β-N-acetyl-d-glucosaminidase (NAG) activity increased from day 3 to day 5, then decreased to normal levels on day 7. Renal ATP concentration and energy charge decreased markedly on day 7. These data indicate that the blood oxygen supply to the tissues began to decrease on day 6 and that renal insufficiency developed in the terminal stage of infection. We concluded that even a moderate increase in the level of plasma urea nitrogen could be a useful index of renal insufficiency in this infection system.

Pathophysiology of hypoxia in mice infected with Plasmodium berghei

Pathophysiological significance of hypoxia in malarial infection was investigated in mice infected with Plasmodium berghei NK65. Intraperitoneal inoculation of mice with 1×107 parasitized red blood cells resulted in death of the hosts 6–7 days later. Anaemia of infected animals developed on day 4 after inoculation and oxygen affinity of whole blood, measured as P50 act pH, increased simultaneously. This change may be a physiological adaptive response to a reduction in oxygen delivery to the tissues to day 5. However, the blood oxygen supply on day 6 appeared to be deteriorating and this is thought to be an important factor contributing to the death of the host. The value of adenylate energy charge in red cells during malarial infection, however, was comparatively well-maintained. Allopurinol stimulated the multiplication of malaria parasites and seems to have induced collapse in host-parasite balance more rapidly. Decrease in blood pH and in blood oxygen transport may be important factors for the pathogenesis of the allopurinol-treated hosts.

Correlation between protective antibody response and patent infection with Hymenolepis nana in mice

Abstract Correlation between protective antibody response and patent infection with Hymenolepis nana in mice. International Journal for Parasitology16: 197–203. Mice inoculated with mouse-derived cysticercoids of Hymenolepis nana, as well as with eggs, produced IgG and IgE antibodies that were detected by double diffusion (DD) and passive cutaneous anaphylaxis (PCA), respectively. When mice inoculated with eggs (day 0) were challenged with eggs (day 66), all were resistant to the challenge (assessed by the failure of cysticercoid recovery in the intestinal tissue) and produced protective antibodies evidenced by passive transfer, as well as IgG and IgE isotypes. When mice inoculated with eggs (day 0) were treated with a highly efficacious cestocide, praziquantel on day 6 at the beginning of the lumen phase, all were also resistant to the egg challenge on day 66, however, IgE, IgG, and protective antibodies were not detected. When mice treated with praziquantel before patent infection were repeatedly challenged with high doses of eggs, some of them produced IgG and IgE antibodies. From these results, it is suggested that (1) the production of protective antibody is a secondary response after patency (which may be ascribed to eggs released from mature worms), and (2) mice initially given eggs are highly resistant to egg challenge showing that an effector mechanism of acquired resistance to egg challenge may be expressed without high titres of protective antibody, at least in the serum.

Eosinophilia in Mouse Regulated by Multiple Factors following Repeated Stimulations with Ascaris Eggs into the Peritoneal Cavity

Repeated injections of viable eggs of Ascaris suum into the peritoneal cavity of BALB/c mice induced marked peritoneal eosinophilia (9.3 X 10(6) cells/mouse, 52.8%) without infection. Extracted antigen (Asc) and eggs that had been killed also were able to induce marked eosinophilia; however, their levels were significantly lower (p less than 0.001). This experimental system was able to demonstrate how various multiple factors cumulatively affected the degree of peritoneal eosinophilia. These factors included: mechanical stimulation, caused by the repeated peritoneal lavages (4.4 X 10(5) cells/mouse), against a background level of peritoneal eosinophils of 4.5 X 10(4) cells/mouse; T-cell-independent stimulation, observed when the viable eggs were injected repeatedly into athymic nude mice (nu/nu; 1.6 X 10(6) cells/mouse), while on the other hand, neither eggs that had been killed nor Asc displayed any T-cell-independent augmentation of eosinophilia; and, T-cell-dependent augmentation of peritoneal eosinophilia, observed in heterozygous athymic mice (nu/+), in thymocyte-reconstituted nu/nu, and in normal BALB/c mice. Egg culture supernatant could not act on bone marrow cells to support eosinophil colony formation. In conclusion, only viable eggs were considered prime inducers, consisting of T-independent and T-dependent parts exerting cumulative effects.

Inhibitory Immunization Using Complete Freund’s Adjuvant on Ongoing Eosinophilia Induced by Repeated Antigen-Stimulations in Guinea Pigs

Ongoing eosinophilia, in guinea pigs repeatedly sensitized with dinitrophenylated (DNP)-Ascaris antigen (DNP-Asc) into the peritoneal cavity, was suppressed significantly by complementary immunizations with a heterologous antigen, e.g., ovalbumin (OA) or bovine gamma-globulin (BGG) emulsified in complete Freunds adjuvant (CFA). Challenge injections of DNP-OA or DNP-BGG elicited peritoneal eosinophilia in animals that were sensitized repeatedly with DNP-Asc. Under these conditions, antigen specificity in suppressive immunization was studied. Eosinophilia, induced by DNP-OA challenge, was suppressed by immunization with either OA in CFA or BGG in CFA. However, Asc (homologous carrier of sensitizing antigen) elicited no suppression. Additionally, CFA, used as an adjuvant, played an important role in suppressive immunization, but CFA alone had no effect in suppressing peritoneal eosinophilia. Anti-DNP antibody, detected by hemagglutination test or passive cutaneous anaphylaxis, was not affected by complementary immunization. These results suggested that peritoneal eosinophilia was suppressed concomitantly by a supplemental immunization in an antigen-nonspecific manner. Eosinophilia in the bone marrow also was suppressed significantly by complementary immunization, but the pattern was quite different from that shown in the peritoneal cavity. The first nuclear cell response peak after challenging, including eosinophils, was stanched completely by CFA itself. The second nuclear cell peak, on day 5, recovered, but eosinophil response continued to be suppressed.

Clinical evaluation of antimalarial regimens in Japan.

The actual situation of the treatment of malaria for the past 10 years in Japan was investigated and analyzed. As a result, it was revealed that there were not a few cases which had been treated improperly probably because of the difficulty of getting antimalarial agents. Moreover, it was made clear that the death rate on falciparum malaria was constantly high, 8.7%, as expected and the relapse rate of vivax malaria was still as high as 18.0%. There was the recrudescence of falciparum malaria at 8.1%, maybe because of the influence of the prevalence of the drug-resistant strains of Plasmodium falciparum. The trouble in getting antimalarial agents has been overcome since 1980. Study Group on Pharmacotherapy of Imported Tropical Diseases was organized by the Ministry of Health and Welfare in 1980, and antimalarial agents have been supplied free of charge through the Study Group for the treatment of the disease. The number of cases of imported malaria has increased in our country. There are a lot of problems to be solved quickly to cope with the situation: people who travel abroad should be enlightened on the danger of the infection of malaria and take prophylactics for the disease and physicians should get familiar with the disease being supplied with information about it.