The reactions of alkaline hydrogen peroxide with lignin model dimers

Summary Guaiacylglycerol--guaiacyl ether (I) was treated with alkaline hydrogen peroxide under simulated technical bleaching conditions in the presence and absence of a peroxide stabilization reagent, Na₅DTPA (sodium diethylenetriaminepentaacetate) and with molecular oxygen under similar conditions. The reaction products were characterized and their yields determined using a combination of gas chromatography and gas chromatography mass spectrometry.In the reaction of I with peroxide, the principal reaction consisted of the displacement of the side chain (Dakin-like reaction) initiated by molecular oxygen and/or other peroxide decomposition products. The displaced side chain, -0-(2-methoxyphenyl)glyceraldehyde, subsequently was dehydrated to -guaiacoxyacrolein which was oxidized by peroxide to guaiacol and glycolic acid. -Guaiacoxyacrolein also gave evidence of undergoing competing condensation reactions in the alkaline medium. The influence of Na₅DTPA in controlling peroxide decomposition was evident after comparing the yields and types of products formed when I was reacted with peroxide in the presence and absence of this stabilizer.The findings are discussed in terms of their relationship to technical peroxide bleaching.Contribution No. 140 from the Empire State Paper Research Institute, State University of New York College of Environmental Science and Forestry, Syracuse, New York. The authors gratefully acknowledge financial support received from the Empire State Paper Research Associates, Inc.     

Hemagglutination by calf diarrhea coronavirus

The virus was grown in BEK-1 cells, a stable cell line from bovine embryo kidney, and tested for hemagglutination (HA) with erythrocytes of a variety of species at 4°C, room temperature and 37°C. HA was observed at all temperatures with chicken, mouse, rat, and hamster erythrocytes but not with erthyrocytes of human (O), cattle, horses, sheep, guinea pigs, geese, ducks, pigeons and 1-day-old chicks. Chickens showed an individual variation in agglutinability of their erythrocytes, requiring selection of birds to obtain erythrocytes for HA. HA reaction was inhibited by specific antiserum. Some factors involved in HA and HA inhibition (HI) were investigated and standard HA and HI tests were worked out.     

The reactions of alkaline hydrogen peroxide with lignin model dimers

Summary Three lignin model dimers of the phenacyl -aryl ether type were treated with alkaline hydrogen peroxide under simulated technical bleaching conditions in the presence and absence of peroxide stabilization agents. The reaction products were characterized and their yields determined using a combination of gas chromatography and gas chromatography-mass spectrometry. The principal reaction in each case consisted in the displacement of the side chain via the Dakin reaction. In the case of one of the dimers, -guaiacoxy--hydroxypropioguaiacone, a competing dehydration reaction occurred, resulting in the formation of guaiacyl -guaiacoxyvinyl ketone, which subsequently was degraded to guaiacol and glycolic acid. Stabilization of the peroxide with Na₅DTPA enhanced the yield of acyclic Dakin products (-guaiacoxy carboxylic acids). Product analysis supported the conclusion that oxygen, formed from the decomposition of peroxide, was itself relatively unreactive in the initial phase of the reaction under peroxide bleaching conditions.Contribution No. 139 from the Empire State Paper Research Institute, State University of New York College of Environmental Science and Forestry, Syracuse, New York. The authors gratefully acknowledge financial support received from the Empire State Paper Research Associates, Inc.     

Toward the development of a weather index insurance for rice farmers in the coastal region of Myanmar

Paddy and Water Environment - Climate change is expected to exacerbate damage to agricultural production from natural disasters. Examination of measures to adapt to the damage represents an urgent...     

Lesional expression of thymus and activation-regulated chemokine in canine atopic dermatitis

Glucocorticoids are reported to bias cytokines to a Th2 phenotype. However, this dogma has been advanced largely from studies utilizing potent glucocorticoid analogs. The current study was conducted to revisit the issue of glucocorticoid modulation of Th1/Th2 cytokine production and evaluate migration inhibitory factor (MIF) mRNA expression in cultured pig splenocytes treated with physiologically relevant concentrations of cortisol (CORT). Dexamethasone (DEX) was included for comparison. In Experiment 1, DEX, at 150 and 300 nM, suppressed concanavalin (ConA)-stimulated IFNgamma at both 12 and 24 h in culture, and IL-10 at 24h (P<0.05). Both 150 and 300 nM CORT suppressed IL-10 at 24 h (P<0.05), but neither concentration affected IFNgamma at 24 h. In Experiment 2, cells were cultured with a broader range of CORT for 48 h following ConA. Parallel cultures with identical treatments also were conducted in separate plates for evaluation of glucocorticoid regulation of MIF mRNA. IFNgamma was reduced by 300 nM DEX at 12, 24, and 48 h (P<0.05), whereas 150 and 300 nM CORT blunted IFNgamma at 24 h (P<0.05), but not 48 h. ConA increased IL-2 (P<0.01), but none of the steroid treatments affected IL-2. At both 12 and 24 h, IL-10 was reduced by 300 nM DEX and by 150 and 300 nM CORT (P<0.05). ConA increased relative abundance of MIF mRNA (P<0.001), but no steroid treatment affected MIF mRNA. In Experiment 3, steroid additions were delayed by 24 h after ConA, and cytokine concentrations evaluated 48 h later. Again, separate cultures were used for determination of effect of treatments on MIF mRNA. None of the steroid treatments affected IFNgamma, but 300 nM DEX reduced IL-10 (P<0.05). All of the CORT treatments (75-300 nM) reduced MIF mRNA (P<0.05), whereas DEX did not affect MIF mRNA in this experiment. The current experiments suggest that both DEX and high physiological concentrations of CORT can suppress both type 1 and type 2-like cytokines in cultured pig splenocytes. But, IL-10 was generally more sensitive to CORT suppression with increased time in culture than was IFNgamma. In addition, MIF mRNA could be suppressed by delayed addition of CORT to porcine splenocytes. Taken together, the data do not support the hypothesis that CORT directs the cytokine milieu toward a type 2 bias in cultured pig splenocytes.     

Effect of mild restriction of food intake on the speed of racing Greyhounds

OBJECTIVE: To determine whether mild restriction of food intake affects clinicopathologic variables, body composition, and performance of dogs undertaking intense sprint exercise. ANIMALS: 9 trained healthy adult Greyhounds. PROCEDURE: Dogs were offered food free choice once daily for 9 weeks until body weight and food intake stabilized. Dogs were then randomly assigned to be fed either 85% or 100% of this quantity of food in a crossover study (duration of each diet treatment period, 9 weeks). Dogs raced a distance of 500 m twice weekly. Clinicopathologic variables were assessed before and 5 minutes after racing; food intake, weight, body composition, body condition score, and race times were compared at the end of each diet period. RESULTS: Compared with values associated with unrestricted access to food, there were significant decreases in mean body weight (by 6%) and median body condition score (from 3.75 to 3.5 on a 9-point scale) and the mean speed of the dogs was significantly faster (by 0.7 km/h) when food intake was restricted. Body composition and most clinicopathologic variables were unaffected by diet treatment, but dogs given restricted access to food had slightly fewer neutrophils, compared with values determined when food intake was unrestricted. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicate that the common practice among Greyhound trainers of mildly restricting food intake of racing dogs to reduce body weight does improve sprint performance. A body condition score of approximately 3.5 on a 9-point scale is normal for a trained Greyhound in racing condition.