Comparison of dendritic cell-mediated immune responses among canine malignant cells

Dendritic cell (DC) vaccination is one of the most attractive immunotherapies for malignancies in dogs. To examine the differences in DC-mediated immune responses from different types of malignancies in dogs, we vaccinated dogs using autologous DCs pulsed with keyhole limpet hemocyanin (KLH) and cell lysate prepared from squamous cell carcinoma SCC2/88 (SCC-KLH-DC), histiocytic sarcoma CHS-5 (CHS-KLH-DC), or B cell leukemia GL-1 (GL-KLH-DC) in vitro. In vivo inductions of immune responses against these tumor cells were compared by the delayed-type hypersensitivity (DTH) skin test. The DTH response against SCC2/88 cells were observed in dogs vaccinated with autologous SCC-KLH-DC, while the response was undetectable against CHS-5 and GL-1 cells in dogs vaccinated with autologous CHS-KLH-DC and GL-KLH-DC. Skin biopsies taken from DTH challenge sites were then examined for immunohistochemistry, and recruitment of CD8 and CD4 T cells was detected at the site where SCC2/88 cells were inoculated in dogs vaccinated with SCC-KLH-DC. By contrast, neither CD8 nor CD4 T cell infiltration was found at the DTH challenge site in the dogs vaccinated with CHS-KLH-DC or GL-KLH-DC. These findings may reflect that the efficacy of immune induction by DC vaccination varies among tumor types and that immune responses could be inducible in squamous cell carcinoma. Our results encouraged further investigation of therapeutic vaccination for dogs with advanced squamous cell carcinoma in clinical trials.     

Epibiotic microorganisms associated with microcrustaceans in overlying water of Philippine paddy fields

Epibiotic microorganisms associated with micro crustaceans in the overlying water of Philippine paddy fields were examined by scanning electron microscopy, and their associations were compared with those observed in Japanese paddy fields (Soil Sci. Plant Nutr., 43, 633-641, 651-664, 1997). Various types of microorganisms, including bacteria, protozoa, and algae, colonized microcrustaceans and their kinds and colonizing patterns varied depending on the kinds of microcrustaceans. Common associations between epibionts and respective micro crustaceans were observed in the Philippines and in Japan: e.g., rodshaped bacteria on Cyclopidae and Cypridopsidae; no microorganisms on Simocephalus spp.     

Establishment and biological characterization of canine histiocytic sarcoma cell lines

Seven novel cell lines from canine histiocytic sarcoma (HS), three of which were disseminated cutaneous HS and four of which were synovial HS, were established. All of the established cell lines had the same morphological (by light and electron microscopic findings), cytochemical (alpha-naphthyl butyrate esterase-positive), and immunohistochemical (vimentin- and lysozyme-positive, and cyto-keratin-negative) characteristics as the original HS tumor cells. All of the established cell lines injected into nude mice subcutaneously produced solid tumors. Because the established cell lines also showed phagocytic and processing activities, the HS tumor cells appear to originate from the mononuclear phagocytic system cells, despite their differences in locations or organs.     

Effects of preventing hyperphagia on glycolipid metabolic abnormalities in Spontaneously Diabetic Torii fatty rats

Spontaneously Diabetic Torii (SDT) fatty rats, made by introducing the fa allele of the Zucker fatty rat into the SDT rat genome, represent a new model of obese type 2 diabetes. SDT fatty ^fa/fa (SDT fatty) rats exhibit overt obesity, hyperglycemia, and hyperlipidemia from about six weeks of age, and this is associated with hyperphagia by an induced disorder of leptin action. The present study was conducted to elucidate whether suppression of hyperphagia can improve reduce abnormalities in SDT fatty rats. SDT fatty rats were subjected to pair-feeding with SDT fatty ^{+/ +} (SDT) rats from 6 to 26 weeks of age, and the effects on metabolic parameters and diabetic complications were assessed. Body weights of the pair-fed rats were similar with those of SDT rats during the experimental period. Improvement of hyperglycemia or hypertriglyceridemia was observed from 8 to 16 or 12 weeks of age in the pair-fed rats, but hypercholesterolemia was not entirely improved during the experimental period. We also examined mRNAs expression in liver, and found that the expression associated with glyconeogenesis, such as glucose-6-phosphatase (G-6-Pase) and phosphoenolpyruvate carboxykinase (PEPCK), tended to decrease in the pair-fed rats, and the mRNA expression of hydroxymethylglutaryl-CoA (HMG-CoA) was elevated. Renal parameters, such as blood urea nitrogen and urinary albumin excretion, were improved in the pair-fed rats. The incidence or progression of diabetic complications, such as renal lesions and cataract, was reduced. In conclusion, suppression of hyperphagia in SDT fatty rats was effective in temporally improving hyperglycemia or hypertriglyceridemia, and reducing the incidence or progression of diabetic complications, but was ineffective in reducing hypercholesterolemia.     

Immunohistochemical localization of steroidogenic enzymes in corpus luteum of wild sika deer during early mating season

We analyzed the localization of steroidogenic enzymes (P450 scc, 3 beta HSD, P450 arom and P450 c17) in the corpora lutea of two Hokkaido sika deer (Cervus nippon yesoensis) during the early mating season. Two corpora lutea were found in each female and the timing of formation of the corpora lutea seemed different. P450 scc, and 3 beta HSD, positive luteal cells were found in both corpora lutea. The existence of two functional corpora lutea from the early mating season through pregnancy suggests that progesterone secreted by two or more corpora lutea is necessary for maintenance of pregnancy in sika deer.     

Control of rabies: epidemiology of rabies in Asia and development of new-generation vaccines for rabies

Rabies is an enzootic viral disease widespread throughout the world. Although it is a vaccine-preventable disease, the annual number of human deaths caused by rabies is estimated to be 32,000 in Asia. Phylogenetic analysis based on sequence data of the partial N gene of rabies viruses in Asia has shown that the viruses are divided into five genogroups, distributed in Middle East, South Asia, South East Asia, Malay, and Arctic regions. The genetic relationships among these rabies viruses agree basically with the results of previous studies. Meanwhile, new types of vaccines are being developed by applying gene manipulation techniques to rabies virus in order to overcome the disadvantages of current vaccines. This article reviews the molecular epidemiology of rabies in Asia and progress made in the development of new-generation rabies vaccines with the goal of elimination or control of rabies in Asia.     

Relationship between relative water content during reproductive development and winter wheat grain yield

Summary Water is often the most limiting factor to winter wheat (Triticum aestivum L.) production in the southern Great Plains of the U.S.A., yet the lack of reliable screening criteria has precluded direct selection for drought resistance in breeding programs. Previous work showed that leaf relative water content (RWC) was highly heritable when measured under field-drought conditions, but its adoption as a screening tool for yield improvement requires further investigation of the genetic relationship between grain yield and RWC. Plants representing high and low yield potential under drought stress, and a random group of plants, were selected from an F₂ population having the pedigree, TAM W-101/Sturdy. Two sets of entries, each comprised of the two parents and 24 F₂-derived lines, were evaluated under a rainshelter in the F₃ (1986) and F₄ (1987) generations to determine differences in leaf RWC during reproductive development. One set of entries did not receive any water after the jointing stage, and the other set was grown under well-watered conditions. A positive relationship was observed between grain yield and RWC measured during anthesis and mid-grain fill, as the high-yield selections maintained a significantly higher RWC than the low-yield selections. Grain yield and RWC were also positively associated among random selections segregating for both traits. Subsequent adjustment of genotype means for differences in reproductive development at time of sampling underscored the need to consider differences in maturity when RWC is the selection criterion.     

Antioxidative compounds from the outer scales of onion

Antioxidative compounds were isolated from the methanol extract of dry outer scales of onion (Allium cepa L.). Nine phenolic compounds (1-9) were finally obtained by reversed-phase high-performance liquid chromatography, and their structures were elucidated by NMR and mass spectrometry analyses. They were the six known compounds, protocatechuic acid (1), 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (2), quercetin 4'-O-beta-D-glucopyranoside (3), quercetin (5), 4'-O-beta-d-glucopyranoside of quercetin dimer (7), and quercetin dimer (8), and three novel compounds, condensation products of quercetin with protocatechuic acid (4), adduct of quercetin with quercetin 4'-O-beta-D-glucopyranoside (6), and quercetin trimer (9). These phenolic compounds were tested for their antioxidant properties using autoxidation of methyl linoleate in bulk phase or free radical initiated peroxidation of soybean phosphatidylcholine in liposomes. The flavonoid compounds having o-dihydroxy substituent in the B-ring were shown to be effective antioxidants against nonenzymic lipid peroxidation.     

CTLA-4 control over Foxp3+ regulatory T cell function

Naturally occurring Foxp3+CD4+ regulatory T cells (Tregs) are essential for maintaining immunological self-tolerance and immune homeostasis. Here, we show that a specific deficiency of cytotoxic T lymphocyte antigen 4 (CTLA-4) in Tregs results in spontaneous development of systemic lymphoproliferation, fatal T cell-mediated autoimmune disease, and hyperproduction of immunoglobulin E in mice, and it also produces potent tumor immunity. Treg-specific CTLA-4 deficiency impairs in vivo and in vitro suppressive function of Tregs-in particular, Treg-mediated down-regulation of CD80 and CD86 expression on dendritic cells. Thus, natural Tregs may critically require CTLA-4 to suppress immune responses by affecting the potency of antigen-presenting cells to activate other T cells.