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Risk factors for the presence of antibodies to Toxoplasma gondii in Norwegian slaughter lambs.

In a study of lambs from 194 sheep flocks from different areas of Norway, 44.3% of the flocks were found seropositive against Toxoplasma gondii using an ELISA test, with antibodies found in 16.2% of the 1940 individual animals. The risk factors for the occurrence of antibodies to Toxoplasma gondii found in the multivariate logistic regression were: daily presence of a young cat in the sheep house (Odds ratio, OR = 4.11, 95% CI = 1.01-19.7); 'atypical' grazing of lambs (OR = 6.35, CI = 2.36-17.11); use of mouse poison in the sheep house (OR = 2.26, CI = 1.02-5.00); farm situated at an altitude > 100 meters above seal level (101-250 m: OR = 1.20, CI = 0.49-2.92; 251-500 m: OR = 4.97; CI = 2.04-12.0; > 500 m: OR = 3.66, CI = 1.33-10.1). A lower risk was found for flocks with perforated metal floors in the sheep house (OR = 0.47, CI = 0.23-0.96) and timber construction of the sheep house (OR = 0.34, CI = 0.15-0.80). Based on these findings it was recommended that farmers avoid keeping young cats in the sheep houses, that close-to-farm grazing be kept to a minimum and that perforated metal floors be used in the sheep houses. However, with such a high seroprevalence, the proposed measures alone would not reduce the occurrence of Toxoplasma in lambs to a level where undercooked lamb can be consumed without posing an unacceptable risk for some consumer groups.

Altitude↗

Thickening of the capillary basement membrane of the quadriceps muscle in Vacor-induced diabetic patients.

The effect of Vacor diabetes mellitus on the quadriceps muscle capillary basement membrane thickness has been examined by the electron microscopic method. With this procedure, it was possible to obtain an objective evaluation of the significance of capillary basement membrane thickening in Vacor diabetes mellitus. The results of such a study on the muscle capillary basement membrane in 10 normal subjects and 9 Vacor-poisoned patients have demonstrated the following: (1) the average basement membrane width of Vacor patients (2801 A +/- SD 614) is over twice that of normal subjects (1300 +/- 185 A), and all 9 cases demonstrated muscle capillary basement membrane thickening; (2) there is a significant association of basement membrane width with age (P less than 0.01), but not with the duration of the disease or fasting blood glucose values in the Vacor group. The results of the present study indicate that diabetes mellitus induced by Vacor poisoning can lead to microangiopathy, and that such basement membrane thickening is an early and consistent finding.

Adolescent↗

Morphological study of nervous system in Vacor-induced diabetic rats.

Patients with Vacor diabetes mellitus frequently developed diabetic ketoacidosis and neuropathy in the early stage of the disease; however, the mechanism of the development of diabetes and its neurologic complications is not known. In this study, oral administration of 100 mg Vacor/kg of body weight was used in Wistar male rats. The rats were sacrificed 6 h after administration to avoid natural expiration. Light microscopy revealed focal hemorrhage and edematous change in the periventricular area of the brain, scattered hemorrhage in the posterior and anterior horns, spongy degeneration and demyelinization in th fasciculus gracilis and cuneatus of the white matter, early degenerative changes in the sciatic nerve, and no change of the vagus. Electron microscopy showed necrosis of the axon, myelin sheaths and glia cells in the spinal cord, while the organelles of the peripheral nerves were unchanged. These findings indicate that Vacor produces various neurotoxicities in the acute toxic phase.

Animals↗

Anaerobic treatment of pinkwater in a fluidized bed reactor containing GAC.

Pinkwater is generated during the handling and demilitarization of conventional explosives. This listed hazardous waste contains dissolved trinitrotoluene (TNT) and cyclo trimethylene trinitramine (RDX), as well as some by-products. It represents the largest quantity of hazardous waste generated by the operations support command, and its treatment produces a by-product hazardous waste--spent granular activated carbon (GAC). Anaerobic treatment in a fluidized bed reactor (FBR) containing GAC is an emerging technology for organic compounds resistant to aerobic biological treatment. Bench scale batch studies using an anaerobic consortium of bacteria fed ethanol as the sole electron donor demonstrated the transformation of TNT to triaminotoluene (TAT), which then degrades to undetectable end products. RDX is sequentially degraded to nitroso-, dinitroso-, trinitroso- and hydroxylaminodinitroso-RDX before the triazine ring is presumably cleaved, forming methanol and formaldehyde as major end products. The bacterial members of the anaerobic consortia are typically found in sludge digesters at municipal or industrial wastewater treatment plants. The results of a pilot scale evaluation of this process that was conducted at McAlester Army Ammunition Plant (MCAAP, OK) over a 1 year period are reported in this paper. The pilot test experienced wide fluctuations in influent concentrations, representative of true field conditions. The FBR was a 20 in. (51 cm) diameter column with an overall height of 15 ft (4.9 m) and a bed of GAC occupying 11 ft (3.4m). Water was recirculated through the column continuously at 30 gpm (114 l/min) to keep the GAC fluidized, and pinkwater for treatment was pumped into the recirculation line. Several flowrates were evaluated to determine the proper mass loading rate (mass of TNT and RDX per reactor volume per time, kg/m(3) per day) which the reactor could handle while meeting the discharge limitations. Based on the tests performed, a 1 gpm (3.785 l/min) rate in the 188 gal (710 l) volume of the fluidized GAC bed was determined to consistently meet the discharge requirements. This information was used to develop a cost estimate for a system capable of treating the total effluent currently produced at MCAAP. The cost of installing and operating this system was compared to the cost of GAC adsorption for MCAAP at current pinkwater generation rates. The GAC-FBR system had an annual operating cost of approximately US$ 19K, compared to US$ 71 K annually for GAC adsorption. When including the amortization of the capital equipment required for the GAC-FBR, the payback period for installation of this new process was estimated at 3.7 years.

Bacteria, Anaerobic↗

Effect of food-grade surfactant on bioremediation of explosives-contaminated soil.

The use of native soil bacteria to biodegrade explosives-contaminated soil under co-metabolic conditions has been demonstrated. The addition of food-grade surfactants could improve the process by enhancing the rates of explosives desorption from soil, thereby increasing the bioavailability of explosives for microbial degradation. The objective of this study was to decrease residence time in the slurry reactor, thereby increasing output and reducing clean-up costs. In this study, Tween 80 (monooleate), served not only as a surfactant but also as the carbon substrate for the soil microorganisms. Four 2l soil slurry reactors were operated in batch mode with soil containing 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). The results indicated that TNT and RDX were removed in all reactors except the control (no added carbon source). The reactor enriched with surfactant and molasses performed better than reactors with either molasses or surfactant alone. The TNT and its metabolite, 4-amino-2,6-dinitrotoluene were removed faster in the reactor with surfactant plus molasses (35 days) than in the reactor with molasses alone as carbon source (45 days). A radiolabeling study of the mass balance of TNT in the slurry reactors showed substantial mineralization of TNT to CO2.

Biodegradation, Environmental↗

Synthesis, characterization and thermal studies of 2-oxo-1,3,5-trinitro-1,3,5-triazacyclohexane (Keto-RDX or K-6).

2-Oxo-1,3,5-trinitro-1,3,5-triazacyclohexane (Keto-RDX or K-6), the most powerful energetic material among nitrourea explosives, has been prepared and scaled up at laboratory level. The identity and purity of the product are tested by elemental analysis, IR, NMR, mass and HPLC techniques. Thermal response and sensitivity experiments on K-6 are also described. The data on sensitivity shows that K-6 can be utilised practically only in phlegmatized form.

Chromatography, High Pressure Liquid↗

Isolation and quantification of fluoroacetate in rat tissues, following dosing of Z-Phe-Ala-CH2-F, a peptidyl fluoromethyl ketone protease inhibitor.

Peptidyl fluoromethyl ketones (PFMK) are irreversible inhibitors of cathepsin B, a cysteine proteinase thought to be involved in the degradation of cartilage. It has been speculated that PFMK inhibitors may metabolize in rodents to form fluoroacetate (FAC), an extremely toxic poison. A highly selective and sensitive separation and detection scheme was developed to measure trace levels of FAC in rat tissues following PFMK dosing. The procedure consisted of extracting FAC from tissue and spiking the extract with [18O]2-fluoroacetate (18O-FAC) as an internal standard. FAC and 18O-FAC were further isolated from matrix components using ion-exchange, solid-phase extraction. The pentafluorobenzyl esters of FAC and 18O-FAC were formed to facilitate the chromatographic separation. Two-dimensional gas chromatography coupled with selected-ion-monitoring detection provided the final measurement. The assay had a limit of detection of 2 ng FAC per g tissue, and was capable of accurately quantitating as little as 10 ng FAC per g tissue with a S/N ratio of 40:1. Linearity was established over two orders of magnitude, from 2-500 ng ml-1, with 5 microliters injected on-column. The method was used to demonstrate that FAC was formed in rats following dosing with Z-Phe-Ala-CH2-F, a PFMK cathepsin enzyme inhibitor.

Animals↗

Comparison of the half-lives and regeneration rates of blood clotting factors II, VII, and X in anticoagulant-resistant and susceptible Norway rats (Rattus norvegicus Berk.).

The half-lives and regeneration rates of clotting factors II, VII, and X in the plasma of anticoagulant-resistant and susceptible rats were determined. There is little or no difference in the half-lives of factors II and X in anticoagulant-resistant rats compared to susceptible rats, but the half-life of factor VII is longer in anticoagulant-resistant rats. In anticoagulant-resistant rats critical clotting factors appear to be carboxylated in preference to factor II, whereas the opposite occurs in susceptible rats; this may contribute to an animal's resistance status.

Animals↗

The toxicity of chlorophacinone and warfarin to house mice (Mus musculus).

Individually caged house mice (Mus m. musculus) were fed 0.025% warfarin (3(2-acetyl-1-phenylethyl)-4-hydroxycoumarin) or 0.025% chlorophacinone (2(1-(p-chlorophenyl)-1-phenyl) acetyl-1,3-indandione) for periods varying from 1 to 21 days. In all, 320 mice, 160 of each sex, were tested.A significant difference was found between the mortalities obtained by the two compounds. In feeding periods varying from 1-5 days chlorophacinone produced a mortality of 60-85% and warfarin only 5-75%. Five per cent, however, did survive 21 days feeding on each compound.A great variation in the susceptibility of individual mice was established for chlorophacinone as well as for warfarin.

Animals↗

The development and use of a test to identify resistance to the anticoagulant difenacoum in the Norway rat (Rattus norvegicus).

Feeding tests were carried out in the laboratory to obtain basic data on the susceptibility of wild Norway rats to difenacoum. The results were used to derive a standard test procedure for the identification of difenacoum resistance in warfarin-susceptible and resistant rats. Details are given of tests on rats from suspected difenacoum-resistant infestations on farms.

4-Hydroxycoumarins↗

Laboratory and field evaluation of pyriminyl as a poison for Rattus norvegicus.

Laboratory tests indicated that the optimum concentration for pyriminyl in rat baits was between 1% and 3%. In field trials in which 0.5% pyriminyl (the concentration in commercial use) was compared with 2.5% zinc phosphide for the control of rats on farms, the pyriminyl treatments were significantly less effective than the zinc phosphide even when the poisoned baits were left down for 7 days instead of 1 day after prebaiting. Both poisons were as effective in medium oatmeal bait as they were in medium oatmeal containing 5% corn oil and 5% sugar.

Animals↗