Sulfur-associated polioencephalomalacia in cattle grazing plants in the Family Brassicaceae

Polioencephalomalacia was diagnosed histologically in cattle from two herds on the Darling Downs, Queensland, during July–August 2007. In the first incident, 8 of 20 18-month-old Aberdeen Angus steers died while grazing pastures comprising 60% Sisymbrium irio (London rocket) and 40% Capsella bursapastoris (shepherd's purse). In the second incident, 2 of 150 mixed-breed adult cattle died, and another was successfully treated with thiamine, while grazing a pasture comprising almost 100% Raphanus raphanistrum (wild radish). Affected cattle were either found dead or comatose or were seen apparently blind and head-pressing in some cases. For both incidents, plant and water assays were used to calculate the total dietary sulfur content in dry matter as 0.62% and 1.01% respectively, both exceeding the recommended 0.5% for cattle eating more than 40% forage. Blood and tissue assays for lead were negative in both cases. No access to thiaminase, concentrated sodium ion or extrinsic hydrogen sulfide sources were identified in either incident. Below-median late summer and autumn rainfall followed by above-median unseasonal winter rainfall promoted weed growth at the expense of wholesome pasture species before these incidents.     

Immunochemical and mass spectrometric analysis of Nε-(carboxymethyl)lysine content of AGE-BSA systems prepared with and without selected antiglycation agents

The present study was designed to compare surface plasmon resonance (SPR) biosensor, enzyme-linked immunosorbent assay (ELISA), and ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) methods for the analysis of Nε-(carboxymethyl)lysine (CML) in glucose-bovine serum albumin (BSA) model systems and to investigate the possible inhibitory effect of selected compounds (α-tocopherol, ferulic acid, rutin, thiamin, thiamin monophosphate, and thiamin pyrophosphate) on CML formation. The reported levels of CML detected were dependent upon the method of analysis employed. The highest reported concentrations were obtained with the SPR biosensor, whereas the lowest were found by ELISA. However, a high correlation was observed between these two immunochemical procedures. CML concentrations were dependent upon the type and concentration of the candidate CML inhibitor. All inhibitory compounds investigated, with the exception of α-tocopherol, decreased the level of CML formation in the glucose-BSA system.     

Effect of inhibitor compounds on Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) formation in model foods

The possible adverse effects on health of diet-derived advanced glycation endproducts (AGEs) and advanced lipoxidation endproducts (ALEs) is of current interest. This study had the objective of determining the effects of the addition of AGE/ALE inhibitors and different types of sugar and cooking oil on Nε-(carboxymethyl)lysine (CML) and Nε-(carboxyethyl)lysine (CEL) formation in model foods (sponge cakes). The cake baked using glucose produced the highest level of CML (2.07±0.24 mmol/mol lysine), whereas the cake baked using fructose produced the highest concentration of CEL (25.1±0.15 mmol/mol lysine). There were no significant differences between CML concentrations formed in the cakes prepared using different types of cooking oil, but significant differences (P<0.001) were observed between the cakes prepared using different proportions of cooking oil. The cakes containing oil generated greater concentrations of CML than sucrose. α-Tocopherol and rutin did not inhibit CML and CEL formation. In contrast, ferulic acid and thiamin, thiamin monophosphate, and thiamin pyrophosphate reduced CML and CEL formation.     

Failure of a single postpartum prostaglandin treatment to improve the reproductive performance of dairy cows

A study was conducted to evaluate the effects of postpartum prostaglandin treatment on reproduction in 3 seasonal calving dairy herds. Recently calved lactating dairy cows were paired on herd, age, calving date and previous production index. One cow in each of the 196 pairs received a single intramuscular injection of 25 mg of the prostaglandin analogue, dinoprost, between 14 and 28 days after calving. Subsequent reproduction was monitored. Within each herd and overall, there was no significant effect of treatment on the intervals from calving to first service, mating start date to first service, calving to conception, mating start date to conception and first service to conception. Treatment also had no significant effect on 21-day submission and pregnancy rates, on the proportion of each group not pregnant at the end of mating, and on first service pregnancy rates. Responses to treatment did not vary between cows calving within 50 days of mating start date and earlier calving cows or between cows aged less than 5 years and older cows.     

Comparison of shoot dry weight, Na+ content and δ13C values of ari-e and other semi-dwarf barley mutants under salt-stress

Four breviaristatum (short awned and semi-dwarf) barley mutants; ari-e.1, ari-e.119, ari-e.156 and ari-e.228 were compared with other semi-dwarf mutants; Golden Promise, Alf, Pallas and Diamant along with their non-mutant parents; Bonus, Foma, Maythorpe, Bomi and Valticky, for response to salt stress. Plants were exposed to hydroponic salt treatments (NaCl at 25 and 175 mol m^-3) for 4 weeks, after which response was measured in terms of shoot dry weight, sodium content and δ¹³C. In general ari-e mutants and Golden Promise had significantly lower Na⁺ contents than the other mutants. They also had significantly more negative δ¹³C values than the other lines in stressed (175 mol m^-3 NaCl) conditions. There was a positive correlation (r = 0.71, p < 0.01) between shoot Na⁺ and δ¹³C values so that δ¹³C became less negative with increasing Na⁺ content. Shoot dry weights were compared to shoot Na⁺ and δ¹³C values. The ari-e and Golden Promise mutants showed less reduction in dry matter production in salt stress relative to the control treatment than all the other lines. The data suggest that ari-e mutants and Golden Promise are better adapted to salt stressed environments than the other lines examined. Tests for gibberellic acid sensitivity revealed that ari-e mutants and Golden Promise responded weakly to GA₃, while other dwarf mutants Pallas, Diamant and Alf along with their parents Bonus, Foma, Maythorpe, Valticky and Bomi were highly sensitive. Our results support previous findings that ari-e mutants and the GPert mutant are allelic. This revised version was published online in July 2006 with corrections to the Cover Date.     

Two-year toxicity and carcinogenicity study of methyleugenol in F344/N rats and B6C3F(1) mice

Methyleugenol (MEG) was tested for toxicity/carcinogenicity in a 2-yr carcinogenesis bioassay because of its widespread use in a variety of foods, beverages, and cosmetics as well as its structural resemblance to the known carcinogen safrole. F344/N rats and B6C3F(1) mice (50 animals/sex/dose group) were given MEG suspended in 0.5% methylcellulose by gavage at doses of 37, 75, or 150 mg/kg/day for 2 yr. Control groups (60 rats/sex and 50 mice/sex) received only the vehicle. A stop-exposure group of 60 rats/sex received 300 mg/kg/day by gavage for 53 weeks followed by the vehicle only for the remaining 52 weeks of the study. A special study group (10 animals/sex/species/dose group) were used for toxicokinetic studies. All male rats given 150 and 300 mg/kg/day died before the end of the study; survival of female rats given 150 mg/kg/day and all treated female mice was decreased. Mean body weights of treated male and female rats and mice were decreased when compared to control. Area under the curve results indicated that greater than dose proportional increases in plasma MEG occurred for male 150 and 300 mg/kg/day group rats (6 and 12 month) and male 150 mg/kg/day mice (12 month). Target organs included the liver, glandular stomach, forestomach (female rats) and kidney, mammary gland, and subcutaneous tissue (male rats). Liver neoplasms occurred in all dose groups of rats and mice and included hepatoadenoma, hepatocarcinoma, hepatocholangioma (rats only), hepatocholangiocarcinoma, and hepatoblastoma (mice only). Nonneoplastic liver lesions included eosinophilic and mixed cell foci (rats only), hypertrophy, oval cell hyperplasia, cystic degeneration (rats only), and bile duct hyperplasia. Mice also exhibited necrosis, hematopoietic cell proliferation, and hemosiderin pigmentation. Glandular stomach lesions in rats and mice included benign and malignant neuroendocrine tumors, neuroendocrine cell hyperplasia, and atrophy and in mice included glandular ectasia/chronic active inflammation. In female rats, the forestomach showed a positive trend in the incidences of squamous cell papilloma or carcinoma (combined). Male rats also exhibited kidney (renal tubule hyperplasia, nephropathy, and adenomacarcinoma), mammary gland (fibroadenoma), and subcutaneous tissue (fibroma, fibrosarcoma) lesions. Male rats also exhibited malignant mesotheliomas and splenic fibrosis. These data demonstrate that MEG is a multisite, multispecies carcinogen.     

Building neural representations of habits

Memories for habits and skills ("implicit or procedural memory") and memories for facts ("explicit or episodic memory") are built up in different brain systems and are vulnerable to different neurodegenerative disorders in humans. So that the striatum-based mechanisms underlying habit formation could be studied, chronic recordings from ensembles of striatal neurons were made with multiple tetrodes as rats learned a T-maze procedural task. Large and widely distributed changes in the neuronal activity patterns occurred in the sensorimotor striatum during behavioral acquisition, culminating in task-related activity emphasizing the beginning and end of the automatized procedure. The new ensemble patterns remained stable during weeks of subsequent performance of the same task. These results suggest that the encoding of action in the sensorimotor striatum undergoes dynamic reorganization as habit learning proceeds.     

Compressibility, Phase Transitions, and Oxygen Migration in Zirconium Tungstate, ZrW2O8

In situ neutron diffraction experiments show that at pressures above 2 kilobars, cubic zirconium tungstate (ZrW2O8) undergoes a quenchable phase transition to an orthorhombic phase, the structure of which has been solved from powder diffraction data. This phase transition can be reversed by heating at 393 kelvin and 1 atmosphere and involves the migration of oxygen atoms in the lattice. The high-pressure phase shows negative thermal expansion from 20 to 300 kelvin. The relative thermal expansion and compressibilities of the cubic and orthorhombic forms can be explained in terms of the "cross-bracing" between polyhedra that occurs as a result of the phase transition.