Variation between hosts in the developmental success of the free-living stages of trichostrongyle infections of sheep

Variation between hosts of different ages and genotypes in the developmental success of trichostrongylid parasite eggs from sheep was investigated in two trials. The percentage development to infective third-stage larvae of eggs collected from lambs and adult ewes infected with Ostertagia circumcincta was compared in an indoor trial. In addition, sheep previously bred for either high or low faecal egg count and grazed outdoors on parasite contaminated pasture were sampled; egg development, faecal egg count, generic profile and faecal dry matter were measured. In both trials, development to L3 was significantly lower in eggs derived from adult ewes than from lambs and, in the field trial, from animals selected for low faecal egg count. The observed differences could not be accounted for by variations in faecal egg count, faecal dry matter content nor by differences in the generic composition of worm egg output. Although not shown conclusively, the results are consistent with an immune mechanism influencing the development of free-living stages of gastrointestinal nematodes outside the host. These results have significant implications for our understanding of parasite epidemiology, particularly as it relates to sources of pasture contamination.     

Pregnancy after pancreas transplantation in the cyclosporine era: report from the International Pancreas Transplant Registry

In haemophilic arthropathy there is a progressive limitation of the range of motion (ROM) which may lead to disabilities in the activities of daily living (ADL). In the literature the pathology of haemophilic arthropathy is described extensively, but only one paper describing functional limitations caused by limited range of motion (LOM) in haemophilia was found. The aim of the pilot study was to estimate on theoretical grounds, how many patients with haemophilia might suffer from functional disabilities. MATERIAL: ROM of elbows, knees and ankles of 155 Haemophilia A and B patients. METHODS: Flexion and extension were measured with an ordinary goniometer. The ROM of joints of patients with haemophilia was compared with normal values. RESULTS: 39 of 155 patients had a normal ROM in both elbows; 22 in one elbow; 34 patients had disabilities in ADL with both arms; 14 with one arm; 18 were able to compensate; 89 had no problems; 79 of 155 patients had a near normal ROM of both knees; 38 patients could not ride an ordinary bicycle. CONCLUSION: Only limited data are available concerning the normal ROM needed for individual ADL. Until additional data are available, it is not possible to predict which patients will be disabled in their activities of daily living and individual counselling should be done during the yearly outpatient comprehensive care clinics. Conservative and surgical measures should be taken to ensure elbow flexion of at least 120 degrees and knee flexion of 100 degrees for Western societies. In Asian countries patients with haemophilia need maximum knee flexion and ankle dorsi flexion.     

Fungal biotransformation of 6-nitrochrysene

The fungus Cunninghamella elegans was used to biotransform 6-nitrochrysene, a mutagen that is a widespread environmental contaminant. After 6 days, 74% of the 3H-labeled 6-nitrochrysene added had been metabolized to two isomeric sulfate conjugates. These conjugates were separated by high-performance liquid chromatography and identified by UV-visible, 1H nuclear magnetic resonance, and mass spectral techniques as 6-nitrochrysene 1-sulfate and 6-nitrochrysene 2-sulfate.     

The deficiency of the ‘economic optimum’ application for evaluating models which predict crop yield response to nitrogen fertiliser

Much effort is devoted to testing N-fertiliser models against measurements of yield in N-fertiliser experiments. We show that the economic optimum application of N-fertiliser can often only be determined very imprecisely from such measurements, even when they are accurate. Hence any attempt to evaluate a simulation model by comparing simulated with experimentally determined optima, or to relate these experimental optima to other factors thought to influence yield, will be uninformative. Big differences between simulated and measured optima will occur even with good models, which may explain the apparent poor performance of some simulation models in the literature.We suggest, instead, the systematic inspection of the differences between simulated and observed yields at the levels of N-fertiliser applied in an experiment. A study of the relationship of these differences to the applied level of N-fertiliser and to other factors of interest will be a more informative method of evaluating a model, and of suggesting other factors for inclusion in it. An example of the use of the method is given.     

Enhancement and suppression of self-stimulation after ventromedial hypothalamic lesions.

Investigated the effects of lesions in the ventromedial hypothalamus (VMH) upon self-stimulation in 25 male hooded Long-Evans rats. Ss trained to press a bar for lateral hypothalamic (LH) stimulation showed an enhancement of responding during the 1st 24 hrs after VMH lesioning, followed by a suppression of responding for several days. The degree of response suppression, but not enhancement, was correlated with an increase in food intake. In Ss trained to shuttle for LH stimulation, only the suppression effect was observed after VMH lesions. Barpressing for dorsal tegmental stimulation was not affected by the lesions. Results suggest that LH stimulation activates at least 2 groups of neurons: one group is specifically involved in barpressing and the other is involved equally in barpressing and shuttling. (French summary) (36 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Response of winter wheat to N-fertiliser: Dynamic model

A concise computer simulation model is described for calculating the growth and N-content of winter-wheat. The validity of the model was tested by means of a new application of statistical theory against the results of nationwide fertiliser experiments having different designs. There was agreement within the limits of experimental error between the measured and simulated values of both total plant and of grain dry weight over the entire range of N-fertiliser treatments in the different experiments. The model also gave good estimates of the %N in the grain provided N-fertilizer levels were not high. Response curves, calculated from the model for grain yield, grain %N, are given for different combinations of potential yield, mineralisation rate and the distribution of inorganic-N down the soil profile.     

The influence of SiC particulates on fatigue crack propagation in a rapidly solidified Al-Fe-V-Si alloy

The fatigue crack propagation properties of a rapidly solidified aluminum alloy are compared with those of a metal matrix composite (MMC) made of the same base alloy with the addition of 11.5 vol pct SiC particulate. The high-temperature base material, alloy 8009 produced by Allied-Signal, Inc. (Morristown, NJ), is solidified and processed using powder metallurgy techniques; these techniques yield a fine-grained, nonequilibrium microstructure. A direct comparison between the fatigue crack propagation properties of the reinforced and unreinforced materials is possible, because alloy 8009 requires no postprocessing heat treatment. As a consequence, this comparison reflects the influence of the SiC particulate and not differences in microstructure that could arise during processing and aging. The experimental data demonstrate that the SiC-reinforced material exhibits modestly superior fatigue crack propagation properties: slower crack growth rates for a given ΔK, at near-threshold crack growth rates. Even when the data are corrected for crack closure using an effective stress intensity factor, ΔK_eff, the composite exhibits lower crack propagation rates than the unreinforced matrix alloy. Microscopic evidence shows a rougher fracture surface and a more tortuous crack path in the composite than in the base alloy. It is argued that the lower crack growth rates and higher intrinsic threshold stress intensity factor observed in the composite are associated with crack deflection around SiC particles. Formerly Graduate Research Assistant, University of California-Davis     

MDA-MB-453, an androgen-responsive human breast carcinoma cell line with high level androgen receptor expression

The role of androgens and the androgen receptor (AR) in the development and progression of breast cancer is poorly understood. To further define a potential model for androgen action in breast cancer, MDA-MB-453 cells, which express AR in the absence of oestrogen receptors and progesterone receptors, were further characterised in terms of AR expression and androgen responsiveness. High level expression of AR was confirmed by northern blot analysis, radioligand binding and immunocytochemistry, and could not be accounted for by AR gene amplification. Three endogenous androgen-responsive genes (fatty acid synthetase, gross cystic disease fluid protein of 15 kDa and prolactin receptor) and a transfected reporter gene, containing an androgen-responsive element, were induced following androgen administration. A synthetic androgen, mibolerone, induced moderate (27% above control) stimulation of MDA-MB-453 cell proliferation, which was abrogated by the simultaneous administration of the synthetic androgen antagonist, anandron, demonstrating that the effect was AR-mediated. In summary, MDA-MB-453 cells express high levels of functional AR, and thus provide a valuable in vitro model for further studies on androgen regulation of gene expression, and perhaps cell proliferation in breast cancer.