Production of stem cell factor in canine mast cell tumors

Mast cell tumor (MCT) is the most common cutaneous tumor in dogs. We recently revealed that production of stem cell factor (SCF) contributes to the proliferation of neoplastic mast cells in an autocrine/paracrine manner. The aim of the present study was to determine the contribution of the mechanism in clinical MCTs. In consequence, high SCF expression (>10 times compared to HRMC cells) was observed in 5 of 7 MCT samples used in the study regardless of KIT mutation, which was confirmed in immunohistochemical analysis. In addition, production of SCF was observed in Ki-67-positive cells in the MCT xenograft. These results indicate the broad contribution of SCF autocrine/paracrine mechanism on clinical MCTs, providing the rationale for the clinical use of KIT inhibitors regardless of KIT mutation.     

Background data of 2-year-old male and female F344 gpt delta rats

Although gpt delta rats, as reporter gene-transgenic rats, were originally developed for in vivo mutation assays, they have also been used to evaluate chemical carcinogenesis and comprehensive toxicity. Therefore, it is necessary to accumulate background data on carcinogenicity and general toxicity in gpt delta rats. Here, we investigated the background data of 110-week-old male and female F344 gpt delta rats and wild-type rats. There was no effect of reporter gene transfection on animal survival rates and body weights during the experiment. The relative weight of male gpt delta rat adrenals was significantly higher than that of wild-type rats, possibly due to the higher incidence of pheochromocytoma. There were no intergenotype differences in the incidence of nonneoplastic lesions in both sexes, including chronic progressive nephropathy and focus of cellular alteration in the liver, which had a higher incidence in both genotypes. Additionally, the significantly higher incidence of adrenal pheochromocytoma in male gpt delta rats than that in wild-type rats was likely incidental because of the lack of differences in the incidences of preneoplastic (male and female) and neoplastic (female) adrenal lesions in both genotypes. Other neoplastic lesions in both sexes showed no intergenotype differences in incidence rates, although large granular lymphocytic leukemia in the spleen and Leydig cell tumors in the testes of males showed higher incidence rates. Overall, there were no effects of reporter gene transfection on the spectrum of spontaneous lesions in F344 gpt delta rats, thus supporting their applicability in evaluating chemical toxicity and carcinogenicity.     

Insect antifeedant activity of flavones and chromones against Spodoptera litura

The antifeedant polymethylated flavones 5-hydroxy-3,6,7,8,4'-heptamethoxyflavone, 5-hydroxy-3,6,7,8-tetramethoxyflavone, and 5,6-dihydroxy-3,7-dimethoxyflavone have been isolated from the cudweed, Gnaphalium affine D. Don (Compositae). These flavonoids and authentic analogues showed insect antifeedant activity against the common cutworm (Spodoptera litura F.). In a previous paper, it was suggested that there was no substituent on the B-ring of the flavonoid for the beneficial antifeedant activity against the common cutworm. These flavonoids having a phenyl group as the B-ring and the chromone as elimination of the B-ring from the flavonoids were used to test the hypothesis of the previously described B-ring effect. The known fact is that Sculletaria baicarensis (Rutaceae) produced the 2-phenyl flavone. Test compounds and their methylated derivatives were prepared from this material for the structure-activity relationship (SAR) study of insect antifeedant activity. In spite of the 2-phenyl flavonoids, some tested compounds did not show any insect antifeedant activity against the common cutworm, although these inactive flavonoids were deficient in the 6-substituent group on the A-ring of the flavonoid. This 6-position-substituted derivative almost showed strong insect antifeedant activity against common cutworm. Moreover, the tested flavonoids having a hydroxyl group as a substituent on any of the positions tended to increase the activity. These results suggested the importance of the 6-position substitution on the flavonoid; however, hydrophilic substituents decreased the activity. Baicalein (5,6,7-trihydroxyflavone) derivatives did not show any activity despite having the 6-substituent derivative. Although the activity of some chromones increased the activity of the flavone, the bulky B-ring was a disadvantage for the antifeedant activity. It was suggested that the charge on C(3) and C(5) of the flavonoid was important for the biological activity. Additionally, an adequate hydrogen bonding property, which is different from lipophilicity, was an advantage for the activity on the basis of a QSAR analysis.     

Site‐directed mutagenesis of the cytochrome b gene and development of diagnostic methods for identifying QoI resistance of rice blast fungus

BACKGROUND: It is possible that a single nucleotide polymorphism (SNP) (G143A mutation) in the cytochrome b gene could confer resistance to quinone outside inhibiting (QoI) fungicides (strobilurins) in rice blast fungus because this mutation caused a high level of resistance to fungicides such as azoxystrobin in Pyricularia grisea Sacc. and other fungal plant pathogens. The aim of this study was to survey Magnaporthe oryzae B Couch sp. nov. isolates in Japan for resistance to QoIs, and to try to develop molecular detection methods for QoI resistance. RESULTS: A survey on the QoI resistance among M. oryzae isolates from rice was conducted in Japan. A total of 813 single‐spore isolates of M. oryzae were tested for their sensitivity to azoxystrobin using a mycelial growth test on PDA. QoI fungicide resistance was not found among these isolates. The introduction of G143A mutation into a plasmid containing the cytochrome b gene sequence of rice blast fungus was achieved by site‐directed mutagenesis. Molecular diagnostic methods were developed for identifying QoI resistance in rice blast fungus using the plasmid construct. CONCLUSION: As the management of rice blast disease is often dependent on chemicals, the rational design of control programmes requires a proper understanding of the fungicide resistance phenomenon in field populations of the pathogen. Mutation of the cytochrome b gene of rice blast fungus would be specifically detected from diseased leaves and seeds using the molecular methods developed in this study. Copyright © 2009 Society of Chemical Industry     

Relationship between the lactation curve and udder disease incidence in different lactation stages in first‐lactation Holstein cows

We examined the relationships between the shape of the first parity lactation curve and udder disease incidence at different stages of lactation in 538 Holstein cows. Data used were first‐parity daily milk yields and treatment records. Each cow was classified according to whether or not it had had udder disease at least once over the whole lactation period or in one of three stages within the lactation period. We then examined the differences in the shapes of the lactation curves between the disease incidence and non‐incidence group in each stage. Cows that had high rates of increase in milk yield and high milk yields in early lactation were predisposed to udder disease afterwards. Cows with high milk production over a long period but with low lactation persistency were predisposed to udder disease after the peak of lactation. There was no difference in total milk yield between incidence and non‐incidence groups in all stages, suggesting that, for a comparable level of lactation, cows without udder diseases have flatter lactation curves.     

Cyclooxygenase 2 and Prostaglandin E2 are not Involved in N-Nitrosodiethylamine-Initiated Early Rat Hepatocarcinogenesis

The present study was undertaken to investigate the effect of dietary supplementation with nimesulide or eugenol on N-nitrosodiethylamine (DEN)-initiated early hepatocarcinogenesis in F344 male rats. Both compounds did not alter the expression of cytochrome P450 (CYP) 2E1, the enzyme that plays a major role in the activation of DEN to genotoxic products; however, nimesulide induced the expression of CYP1A1. Western blot analysis revealed that COX-1 and COX-2 protein expressions were not modulated by DEN compared with normal controls. Furthermore, post-initiation feeding with nimesulide or eugenol did not modulate COX-2 protein expression in normal or DEN-treated rats, whereas eugenol significantly increased the liver prostaglandin E(2) (PGE(2)) levels of DEN-injected animals compared with the DEN controls. Ultimately, nimesulide or eugenol did not modify DEN-induced hepatocarcinogenesis as evidenced by insignificant changes in the number and size of preneoplastic placental glutathione S-transferase (GST-P) positive liver foci compared with the DEN controls. These results suggest that COX-2, as well as prostaglandin E(2), may play no role in the post-initiation development of DEN-induced rat hepatocarcinogenesis at an early stage.     

Enhanced absorption of anthocyanins after oral administration of phytic acid in rats and humans

Many studies on the bioavailability of polyphenols have been reported. However, the relative urinary excretions of AC are also low, ranging from 0.004% to 0.1%. By contrast, other polyphenols show higher urinary excretion levels. Here, we studied the enhancing effects of phytic acid (IP6) on absorption of blackcurrant anthocyanins (BCAs) in rats and humans. In rats after oral administration of BCAs (as 241 mg of AC/kg body weight) in IP6 (0%, 0.25%, 0.5%, 1%, 2.5%) solution, the ACs recovery in urine was increased dependent on IP6 dose. These results suggest that the IP6 enhances gastrointestinal absorption of ACs. At the further analysis of IP6 enhancement effect in rat, whereas BCAs were normally passed through the stomach and duodenum within 2 h, in IP6 group, after 2-6 h post-administration, stomach and jejunum content's weights were specifically heavy, and large amounts of ACs were also detected in stomach, duodenum, and jejunum. These results suggested that the mixture of BCAs and IP6 reduced the gastrointestinal motility. Prolongation of ACs residue in gastrointestinal tract then caused the enhancing effects of IP6 on absorption of AC. In the human study, each subject was orally administrated a BCA beverage containing BCA concentrate (AC 4 mg/kg body weight), 1% of IP6, and 1% of sodium citrate as a pH stabilizer. Both the plasma level and the urinary excretion of AC were increased as compared to BCA administration without IP6. AC intake with IP6 may increase the bioavailability of AC to the comparative level as other polyphenols. Yet, phytic acid, being a strong chelator of important minerals, contributes to mineral deficiencies. An interference with iron uptake has been reported. Safety tests are therefore necessary before high dose IP6 can be used in foods.     

Pathological findings of Japanese Black Cattle living in the restricted area of the Fukushima Daiichi Nuclear Power Plant accident, 2013–2016

Fifty‐one Japanese black cattle from four farms in the evacuation zone of the Fukushima nuclear accident were examined pathologically during the period, 2013–2016. We found no evidence of a radiation effect on pathological findings in any of these autopsy cases, although nine cases (3.7%) of enzootic bovine leukosis (EBL) and three cases (1.2%) of goiter were diagnosed. Estimated integrating dose of external exposure in EBL cases ranged from a maximum of 1200 mSv to a minimum of 72 mSv. Clinically, five cases showed wobble, dysstasia or paralysis. Exophthalmos was observed in three cases. Macroscopically, enlarged lymph nodes, multiple irregular masses of intra‐abdominal and intrapelvic adipose tissue, diffuse thickening of the abomasal submucosa with ulceration, and numerous white nodules of myocardium were observed. Histologically, neoplastic lymphoid cells were extensively proliferated and infiltrated in the lesions. Lymphoid tumor cells showed mature or large lymphoblastic appearance. Immunohistochemically, tumor cells were positive for BLA‐36, CD20 and CD5, and negative for CD3. Three cases showed diffuse enlargement of the thyroid gland with no mass or nodule lesion. Histologically, diffuse proliferation of follicular epithelium was observed with preservation of normal structures. There were no malignant findings such as cellular atypia or invasion to capsule.