Cost effectiveness of reducing dioxin emissions from municipal solid waste incinerators in Japan

The main sources of dioxin emissions are municipal solid waste incinerators. The Japanese national government has set an emission standard for dioxins to reduce dioxin exposure levels. In this study, cost-effectiveness analyses are carried out regarding countermeasures that were recently taken and are being taken at municipal solid waste incinerators in Japan. Annual costs were estimated by telephone survey and model calculations. Annual decrease in the incidence of cancer was estimated in three steps. First, the annual decrease in the volume of dioxin emissions was estimated. Next, using a mathematical model, the annual decrease in human exposure was estimated. Finally, the annual decrease in the incidence of cancer was estimated by applying the cancer slope factor. When annual costs are divided by the annual number of life-years saved, cost per life-year saved (CPLYS) was obtained. CPLYS was estimated to be 7.9 million yen for emergency countermeasures and 150 million yen for long-term countermeasures. However, it must be noted that these obtained CPLYSs are highly dependent on the cancer slope factor and should be considered as an upper limit since there may be a cancer effect threshold.     

Studies of synthesis and permeabilities of special polymer membranes. LI. Active transport of halogen ions through chitosan membranes

Anion exchange membranes containing amino groups, insoluble in acidic and alkaline aqueous solutions, were prepared from chitosan, poly(vinyl alcohol), and glutaraldehyde. Using the membrane in a diaphragm cell, one side being adjusted to be acidic and the other alkaline, it was possible to transport actively halogen ions through the membrane from the acidic side to the alkaline side against the concentration gradient between both sides of the membrane. The active transport of halogen ions through the membrane was significantly influenced by the pH difference and electric potential difference between both sides of the membrane.     

Combined addition of glutathione and iron chelators for decrease of intracellular level of reactive oxygen species and death of Chinese hamster ovary cells

The combined addition of reduced form of glutathione (GSH) and iron chelators for decrease of the intracellular level of reactive oxygen species (ROSs) and death of Chinese hamster ovary (CHO) cells was investigated. The addition of GSH to the serum-free cultures of CHO cells markedly lowered the intracellular ROS level, which effect was comparable to that of the addition of serum (0.4, 10%) and might be due to the reduction of ROS. The addition of iron chelators, deferoxamine and aurintricarboxylic acid, to the serum-free cultures also decreased the intracellular ROS level and increased the residual concentration of viable cells during the serum-free maintenance culture, which should be due to the inhibition of the Fenton and Harber-Weiss reactions stimulating the synthesis of ROS. The combined addition of GSH and the chelators decreased ROS level and cell death more effectively compared with their single addition.     

Transduction of static pressure signal to expression of human granurocytes macrophage colony stimulating factor mRNA in Chinese hamster ovary cells

The expression level of human granurocytes macrophage colony stimulating factor (hGM-CSF) mRNA in Chinese hamster ovary (CHO) DR1000L4N cells increased by 24% with pressurization. Treatment of cells with chelerythrine chloride (10 nM, 15 min), an inhibitor of protein kinase C (PKC), did not suppress the pressure-induced (0.9 MPa) expression of hGM-CSF mRNA, while it decreased the hGM-CSF gene expression level at normal pressure (0.1 MPa). Treatment with U0126 (20 microM, 60 min), a specific inhibitor of extracellular signal-related kinase (ERK1/2), decreased the expression level of hGM-CSF mRNA at 0.1 MPa to 80% of that without U0126 treatment. Similarly, treatment with U0126 decreased the pressure-induced (0.9 MPa) expression level of hGM-CSF mRNA to 79% of the control expression level at 0.1 MPa without treatment. The amount of intracellular phosphorylated ERK1/2 increased with pressurization (0.9 MPa). These results suggest that the pressure-induced expression of hGM-CSF mRNA in CHO DR1000L4N cells depends not on PKC but on the ERK1/2 signaling cascade.     

Lipid components,fatty acid distributions of triacylglycerols and phospholipids in rice brans

Endogenous tocochromanols in extracted lipids from rice brans of the five cultivars were determined by high-performance liquid chromatography, and were investigated in relation to the fatty acid (FA) distribution of triacylglycerols (TAG) and phospholipids (PL). The dominant tocols were α-tocopherol and γ-tocotrienol, followed by α-tocotrienol and with much smaller amounts of γ-tocopherol and δ-tocotrienol. The lipids of these rice brans comprised mainly TAG (80.6–86.0 wt.%), free FA (4.2–9.0 wt.%), and phospholipids (5.5–6.7 wt.%), whilst other components were also detected in minor proportions (0.2–2.1 wt.%). The PL components included phosphatidyl choline (31.8–46.8 wt.%), phosphatidyl ethanolamine (25.0–38.9 wt.%) and phosphatidyl inositol (20.2–23.2 wt.%). Comparison of these different cultivars showed, with a few exceptions, no significant differences (P > 0.05) in FA distribution. FA distribution of TAG among the five cultivars was evident in the rice brans: unsaturated FA were predominantly concentrated at the sn-2 position and saturated FA primarily occupying the sn-1 or sn-3 position. These results suggest that the tocopherol content, lipid component, and FA distribution in rice brans are not dependent on the cultivation areas during the growing season.     

Selective retension of active cells employing low centrifugal force at the medium change during suspension culture of Chinese hamster ovary cells producing tPA

The effect of centrifugal force applied for cell separation at the medium change on the growth, metabolism and tissue plasminogen activator (tPA) productivity of Chinese hamster ovary (CHO) cells suspension culture was investigated. The viability of the precipitated cells increased exponentially as the centrifugal force decreased. However, the cell recovery was lower than 91% when centrifugal forces applied for 5 min was less than 67 x g. In cultures incubated for 474 h with 7 medium changes employing centrifugal forces ranging from 67 to 364 x g, a centrifugal force lower than 119 x g resulted in higher specific rates of growth, glucose consumption, and lactate and tPA production during the whole culture period. On the other hand, daily centrifugation at 67 to 537 x g without discarding the supernatant had no effect on the specific rates. The cultures inoculated with cells precipitated at a centrifugal force of 67 x g showed apparently higher specific rates of metabolism compared to those inoculated with cells in the supernatant. The cells in the supernatant and the precipitate obtained following centrifugation at 67 x g have average diameters of 15.5 and 17.4 microm, respectively. The intracellular contents of amino acids, especially nonessential amino acids, of the precipitated cells were markedly higher than those of the cells in the supernatant. These results indicate that large cells with high amino acid content and metabolic activity were selectively retained in the culture by means of centrifugation at low forces such as 67 x g. Consequently, application of a low centrifugal force is recommended for medium change in order to maintain higher specific productivity of suspended mammalian cells in perfusion culture.     

Role of Heavy Meromyosin in Heat‐Induced Gelation in Low Ionic Strength Solution Containing l‐Histidine

The gelation of myosin has a very important role in meat products. We have already shown that myosin in low ionic strength solution containing l ‐histidine forms a transparent gel after heating. To clarify the mechanism of this unique gelation, we investigated the changes in the nature of myosin subfragments during heating in solutions with low and high ionic strengths with and without l ‐histidine. The hydrophobicity of myosin and heavy meromyosin (HMM) in low ionic strength solution containing l ‐histidine was lower than in high ionic strength solution. The SH contents of myosin and HMM in low ionic strength solution containing l ‐histidine did not change during the heating process, whereas in high ionic strength solution they decreased slightly. The heat‐induced globular masses of HMM in low ionic strength solution containing l ‐histidine were smaller than those in high ionic strength solution. These findings suggested that the polymerization of HMM molecules by heating was suppressed in low ionic strength solution containing l ‐histidine, resulting in formation of the unique gel.     

Combination effect of phospholipids and n-3 polyunsaturated fatty acids on rat cholesterol metabolism

This study evaluated phospholipids (PLs) containing n-3 polyunsaturated fatty acids (n-3 PUFAs) for their specific inherent effects and effects due to a combination of the presence of glycerophosphate structure and n-3 PUFAs on cholesterol metabolism in rats. Rats were fed a diet of AIN-93G containing soybean oil (SO, 7%), SO (5.8%)+fish oil (1.2%), SO (5.2%)+soybean PLs (1.8%), SO (5.2%)+PLs containing n-3 PUFAs (1.8%), and SO (4.0%)+fish oil (1.2%)+soybean PLs (1.8%). Diets with PLs containing n-3 PUFAs, and soybean PLs in combination with fish oil, resulted in decreased serum and liver cholesterol levels through enhancement of fecal cholesterol excretion and suppression of liver sterol regulatory element binding protein-2 mRNA expression compared with the diet containing soybean oil alone. This study shows that soybean PLs with added triacylglycerol that included n-3 PUFAs have the same effects on cholesterol metabolism as PLs containing n-3 PUFAs, and that these could be of benefit to people.