Mitsuyoshi Miyahara

High oleic acid oil suppresses lung tumorigenesis in mice through the modulation of extracellular signal-regulated kinase cascade

This study was undertaken to estimate the effect of dietary high oleic acid oil (OA) on 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in mice. Diet containing 10% oil was fed to mice through experimental periods. On day 30 after NNK injection (100 mg/kg body weight, i.p.), the treatment increased the level of prostaglandin E2 (PGE2) as well as proliferating cell nuclear antigen, a marker of cell proliferation in a high linoleic acid oil (LA)-fed group but not in an OA-fed group. The NNK treatment also induced the activation of an extracellular signal-regulated kinase (Erk) cascade (Erk, Mek and Raf-1) in an LA-fed group. On the other hand, OA feeding abolished the NNK-induced activation of the Erk cascade. In conjugation with these events, OA feeding reduced lung tumor incidence and tumor multiplicity (percentage of mice with tumors) in mice compared with LA feeding at the 20th experimental week. These results suggest that OA suppresses lung tumorigenesis and that this suppression is correlated with the inhibition of PGE2 production and inactivation of the Erk cascade.

Effect of the unsaturation degree on browning reactions of peanut oil and other edible oils with proteins under storage and frying conditions

Abstract Modified peanut oil cultivars with 3–6% linoleic acid such as SunOleic, are much more stable against oxidation, and thus against browning discolouration than traditional peanut cultivars. Interaction products using SunOleic peanuts are much less coloured, which is important for the production of snacks, crackers and peanut butter.

Interactions between phospholipids, saccharides and oxidized lipids in non-enzymic browning reactions

Abstract In addition to browning products analogous to those occurring in oxidizing lipids, other types of browning reactions were observed that produced by intermolecular or intramolecular interactions between amine groups of phospholipids and hydroperoxides or their carbonylic degradation products. Primary amine groups of phosphatidylethanolamine, phosphatidylserine and the respective lysophospholipids react with oxidized acyl chains of phospholipids, forming yellow or red oxidation products. Polyunsaturated imines (Schiff bases) are formed, which rapidly turn brown. The presence of amine groups accelerates browning reactions, slowly on storage, rapidly on heating.

Protective effects of components in peanut skins against D-galactosamine-induced rat hepatic injury

The water extract powder (WEP) from normal oleic acid peanut skins at a dose of 200 mg/kg significantly inhibited the increases of serum bilirubin and the serum concentrations of AST, ALT, and GGT, marker enzymes for liver injury, in D-galactosamine (GalN)-induced liver injury rats. However, the WEP from high-oleic acid peanuts skins appeared to be less effective than that from normal ones at the same dose. trans-Resveratrol (0.67 mg/kg) and quercetin (0.67 mg/kg) were used for comparison. Their protective effects were as strong as that of the WEP from normal oleic acid peanut skins. These results indicated the ability of the WEP of peanut skins, especially from normal oleic acid peanut varieties, to ameliorate hepatic damage and suggested that they may contain the hepatoprotective agents, thought to be mainly polyphenolic compounds. Total polyphenolic content was higher in the WEP from normal oleic acid peanut skins, while the DPPH radical scavenging activity was higher in the WEP from high oleic acid peanut skins. Compared to high oleic acid peanut skins, normal oleic acid ones had a two-fold higher content of resveratrol, whereas no great differences were observed in the quercetin content analysed by reversed phase HPLC with UV detection.

Prostaglandin E 2 -dependent activation of Src-Stat3 signal pathway in human lung adenocarcinoma cells

Accumulating evidence suggests that overproduction of prostaglandin (PG) E2 attributable to induction of cyclooxygenase-2 plays an important role in the development of lung adenocarcinoma. Recently, we have reported that a PGE2 receptor, EP3 is involved in appearance of malignant phenotype of a lung adenocarcinoma cell (A549 cell). In line with our previous study, here we investigated if Src signaling could be involved in PGE2-stimulated growth of A549 cells via EP3. PGE2-dependent cell growth in A549 cell positively related to the activation of Src. A specific antagonist against EP3 abrogated the cell growth and Src activation in the cells stimulated with PGE2. Also, the inhibition of Src activity suppressed its downstream signaling related to cell growth as well as the cell growth in the cells treated with PGE2. These results indicate that PGE2-dependent activation of Src signaling via EP3 plays an important role in growth of A549 cells.

Usefulness of nutrient agar supplemented with NaCl in detection of heat-injured Escherichia coli.

We examined the effect of composition of agar medium for the detection of viable cells of Escherichia coli JCM1649T. The nutrient agar supplemented with NaCl (NA) and two commercial products of plate count agar (standard method agar) exhibited practically the same level of colony count for intact cells, but NA was the most suitable for the detection of sublethally injured cells induced by heat treatment at 55°C for 15 min. Addition of 0.5% NaCl to the commercially-available plate count agar improved the detection rate of heat-injured cells, while glucose in the agar medium was found to decrease the detection rate. NA was shown to be useful as repair medium in the selective detection of heat-injured E. coli.

Effect of Temperature, Moisture and Fat Contents on the Thermal Conductivity of Meats.

熱伝導率の測定法には定常法と非定常法がある,挽肉(牛肉,豚肉,鶏肉)に脂肪を配合して平行熱源法と線熱源法を用いて5～60℃の温度域における熱伝導率を測定した.その結果,平行熱源法では温度上昇に伴って熱伝導率がわずかに上昇する傾向が観察されるのに対し,線熱源法では温度上昇による影響が少ないことが認められた.また,水分含量と熱伝導率との間には正の指数比例関係,脂肪含量と熱伝導率との間には負の指数比例関係があり,この2成分因子から熱伝導率を求める推定式は牛肉では次のとおりであった.ただし,λp, λhはそれぞれ平行熱源法及び線熱源法による熱伝導率(W/(m・K)),x1…水分(%),x2…粗脂肪(%).