Seasonal changes in cortisol sensitivity and glucocorticoid receptor affinity and number in leukocytes of coho salmon

To determine if there were organ-specific changes in immune responses or immune-endocrine interaction, we monitored in vitro immune response, cortisol sensitivity and number and affinity of glucocorticoid receptors (GR) in leukocytes from freshwater-adapted juvenile coho salmon (Oncorhynchus kisutch) during the physiological changes that prepare them to enter the marine environment. During this period, absolute immune response declined, but splenic leukocytes generated more antibody-producing cells than did cells from anterior kidney. Splenic leukocytes were initially more sensitive to the suppressive effects of cortisol and had fewer GR than leukocytes from the anterior kidney. Leukocytes from the anterior kidney were initially insensitive to cortisol but developed sensitivity at about the same time as the dissociation constant and number of GR increased. In vitro incubation of anterior kidney leukocytes in cortisol altered GR variables when experiments were conducted during March through September but not during November through February. In some years, changes in GR or immune responses were correlated with plasma cortisol titers, but in other years there was no correlation. Thus, the exact relation between cortisol, GR and immune response in anadromous salmonids is unclear and other factors are involved.     

Assessment of organoleptic postmortem inspection techniques for bovine offal

Objective To evaluate organoleptic postmortem inspection techniques for bovine livers and kidneys.
Study design At Australian export abattoirs, bovine liver and kidneys are assessed and graded by qualified meat inspectors during normal operations. Over a 12-month period at a large abattoir in eastern Australia during 1997 and 1998, a sample of these organs was reassessed independently using a range of pathological and microbiological methods. Agreement between routine inspection and independent assessment was evaluated using methods of inter-rater agreement.
Results A total of 944 livers and 1374 kidneys were included in the study. All of these organs had been classified during routine inspection. The authors examined 363 livers and 329 kidneys both grossly and histologically, including 36 livers and 14 kidneys that were also subjected to microbiological examination. All other organs were only examined grossly. There was only a moderate level of agreement between the routine and independent assessment methods. For livers, the percentage agreement was 80.2%, McNemar's test of symmetry 55.2 (3 degrees of freedom, P < 0.001) and kappa 0.63. For kidneys, the percentage agreement was 67.8%, McNemar's test of symmetry 9.9 (1df, P = 0.002) and kappa 0.35.
Conclusions The results reinforce concerns from a number of authors about organoleptic postmortem inspection. Risk assessment methodologies offer the opportunity to modify inspection techniques in a manner that is most relevant to current public health concerns.     

A greenhouse study of northern red oak seedling growth on two forest soils at different stages of acidification

The objective of this study was to determine whether or not Ca and P in soils from two forested sites at two different stages of acidification were limiting growth of red oak seedlings. The A and E horizons of a Berks soil from Watershed 4 at the Fernow Experimental Forest (cation exchange buffer range) and a Hazelton/Dekalb soil from Pea Vine Hill in Southwestern Pennsylvania (Al buffer range) were placed in pots and utilized as the growth medium for northern red oak seedlings in a greenhouse environment. Soil water NO₃-N, Ca, Mg, and K concentrations were significantly higher (α≤0.05) on the Berks soil. Soil exchangeable P and soil solution TP (total phosphorus) were significantly higher (α≤0.10) on the Hazelton/Dekalb soil. Both soils were amended with bone meal (CaPO₄) to determine the effects of Ca and P addition on the growth and nutrient uptake of the seedlings. Height growth of the control red oak seedlings was significantly (α≤0.05) greater on the Berks soil after 45 d, but amendment of Hazelton/Dekalb soil with bone meal eliminated this difference. Bone meal addition to the Hazelton/Dekalb soil resulted in significantly greater (α≤0.05) height growth of red oak seedlings when compared to red oak seedlings grown on unamended Hazelton/Dekalb soil, but did not have a similar effect for red oak seedlings grown on Berks soil. Bone meal addition to Hazelton/Dekalb soil resulted in greater (α≤0.05) concentrations of Ca and Mg in red oak leaves. Unfertilized Berks red oak seedling leaves had significantly higher (α≤0.05) concentrations of Ca and K than their Hazelton/Dekalb counterparts. Al/Ca molar ratios were significantly lower on the Berks soil. Red oak height growth was increased significantly by Ca addition to the Hazelton/Dekalb soil.     

Spatial analysis of seroconversion of sentinel cattle to bluetongue viruses in Queensland

Objective To assess quantitatively the spatial distribution of seroconversion of Queensland cattle to bluetongue viruses.
Design A sentinel herd study. Sample population Sixty-nine sentinel herds at 30 locations.
Procedure Spatial clustering of seroconversion to blue-tongue viruses was investigated during the period from 1990 to 1994.
Results Seroconversion to only two bluetongue virus serotypes, 1 and 21, was observed. The 14 herds, in which seroconversion to bluetongue virus serotype 1 was detected, were located only along the eastern coastal and subcoastal region of Queensland, and were significantly (P < 0.05) clustered. Locations at which seroconversion to serotype 21 was detected, were not significantly clustered. The results generally agree with field observations, except for the failure to detect seroconversion to bluetongue viruses in north-western Queensland.
Conclusion Bluetongue infection of cattle in north-western Queensland may be temporally sporadic. The dominance of serotype 1 in the Queensland cattle population may be the result of differential transmission by potential vector species. Long-term surveillance programs are important for defining disease status of animal populations.     

Detection of Clostridium perfringens epsilon toxin by ELISA

An enzyme-linked immunosorbent assay (ELISA) has been developed as an alternative to neutralisation tests in mice to detect Clostridium perfringens type D epsilon toxin in the intestinal contents of animals which have died from suspected enterotoxaemia. The test was sensitive and quantitative and gave excellent agreement with the mouse protection test.     

The synthesis of potential insecticides designed to bind to the acetylcholine receptor

A variety of compounds designed to bind to the acetylcholine receptor, a largely unexploited target for new insecticides, have been prepared. These are related to either the isothiocyanates prepared previously in our laboratory, which probably bind to the receptor, or to nereistoxin, which is known to do so. Many of the compounds are insecticidal, and electro-physiological studies on a candidate compound, N,N-dimethyl-3-thiocyanato-2-(thiocyanatomethyl)propionamide, suggest they may have the predicted mode of action.     

Large-scale molecular dynamics simulations of dislocation intersection in copper

The results of massively parallel three-dimensional molecular dynamics simulations of the perpendicular intersection of extended dislocations in copper are reported. The intersection process, which involves three of the four possible 111 glide planes in the face-centered cubic lattice, begins with junction formation, followed by unzipping, partial dislocation bowing, cutting, and, finally, unit jog formation. The investigation provides insights into this complex atomistic process, which is currently not accessible to experimental investigation.     

Past temperatures directly from the greenland ice sheet

A Monte Carlo inverse method has been used on the temperature profiles measured down through the Greenland Ice Core Project (GRIP) borehole, at the summit of the Greenland Ice Sheet, and the Dye 3 borehole 865 kilometers farther south. The result is a 50, 000-year-long temperature history at GRIP and a 7000-year history at Dye 3. The Last Glacial Maximum, the Climatic Optimum, the Medieval Warmth, the Little Ice Age, and a warm period at 1930 A.D. are resolved from the GRIP reconstruction with the amplitudes -23 kelvin, +2.5 kelvin, +1 kelvin, -1 kelvin, and +0.5 kelvin, respectively. The Dye 3 temperature is similar to the GRIP history but has an amplitude 1.5 times larger, indicating higher climatic variability there. The calculated terrestrial heat flow density from the GRIP inversion is 51.3 milliwatts per square meter.