Believes puppy mills should be eradicated.
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Animal Welfare↗
Biomedical subjects
D K Allen
Publications and source records attributed to D K Allen.
Incorporation of (15)N from spiked cattle dung pats into soil under two moorland plant communities.
The rate and depth of cattle dung incorporation into moorland soil may be an important factor influencing plant community dynamics through its effects on soil nutrient availability. This study traces the incorporation of (15)N-labelled dung into a moorland soil under two vegetation types in Dartmoor National Park, UK. Cores of treated and control soil 10 cm deep were collected at 2, 4, 8 and 16 week intervals and divided into 2 cm depth increments. Soil samples were freeze-dried, ground and analysed for atom% (15)N and %N content using continuous-flow isotope-ratio mass spectrometry. The contribution of dung N to the soil N pool was estimated by changes in atom% (15)N of the soil. The incorporation of dung dry matter into the soil was also calculated. The labile component of the dung N was incorporated deeper and more rapidly into soil under grass than under heather vegetation. The implications of these processes for the dynamics of upland plant communities are considered in relation to the ability of plants to compete for nutrients.
Animals↗
The nitrogen handling characteristics of white clover (Trifolium repens L.) cultivars and a perennial ryegrass (Lolium perenne L.) cultivar.
Ryegrass (Lolium perenne L.) and white clover (Trifolium repens L.) have contrasting responses to soil mineral N availability and clover has the ability to fix atmospheric N(2) symbiotically. It has been hypothesized that these differences are the key to understanding grass-clover coexistence and vegetative dynamics in pastures. However, the whole plant response of clover and ryegrass to mineral N availability has not been fully characterized and inter-cultivar variability in the N-handling dynamics of clover has not been assessed. A detailed experimental study to address these issues was undertaken. For all clover cultivars and ryegrass, mass specific mineral N uptake rates (of whole plants) were similar saturating functions of mineral N availability. For all clover cultivars total N assimilation rates, whole plant C : N ratios and root : shoot ratios were independent of mineral N availability. Clover growth rates were also independent of mineral N availability except for a slight (<10%) reduction at very low N availability levels. Specific N(2) fixation rate (whole plant) was precisely controlled to ensure fixation balanced the deficit between mineral N uptake and the total N assimilation required to maintain constant whole plant C : N ratio. There was always a deficit between N uptake and the total N assimilation required to maintain C : N ratio. Consequently, some N(2) fixation remained engaged even at high mineral N availability levels. All inter-cultivar variation in N(2) fixation dynamics could be attributed to variations in growth rate. Clover mass specific growth rate declined as plant size increased. Ryegrass specific growth rate, whole plant C : N ratio and root : shoot ratio were dependent on N availability. Increased N availability led to increased growth rate and decreased C : N and root : shoot ratios. Specific growth rate was also dependent on plant size, growth rate declining as plant size increased. It is concluded that clover inter-cultivar variation in field performance is unlikely to be a consequence of variation in N-handling characteristics. Inter-cultivar differences in growth rate are likely to be a much more important source of variation.
Nitrogen↗
Mange, overpopulation in dogs on the rise in postwar Tarawa.
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Animals↗
Comparison of thioltransferase (glutathione:disulfide oxidoreductase) from various rat tissues.
Thioltransferase activity was detected in kidney, heart, epididymal fat pads and skeletal muscles, and was inhibited at high concentrations (greater than 1.6 mmol/l) of reduced glutathione. With several disulfide substrates the Vmax and Km for thioltransferase in kidney, heart, soleus and extensor digitorum longus were considerably smaller than in liver. The enzyme from tibialis anterior showed similar kinetic constants as from liver with certain substrates but not with L-cystine.
Amino Acids, Sulfur↗
Function of pituitary-thyroid axis in copper-deficient rats.
Thirty male weanling Sprague-Dawley rats were fed either a copper deficient diet (0.85 mg Cu/kg) or a copper-adequate diet (8 mg Cu/kg). After 7 weeks, the rats were fasted for 12 hours, and injected intravenously with thyrotropin-releasing hormone (TRH, 30 ng/100 g body weight). Six rats from each treatment were killed at 0, 0.5, 1, 2 and 4 hours after TRH injection. Sera obtained at 0, 0.5 and 1 hour, and at 0.2 and 4 hours were used for the radioimmunoassay of thyroid-stimulating hormone (TSH) and thyroxine (T4), respectively. Reduction in liver copper content confirmed that the rats fed the test diet were copper-deficient. Serum TSH levels appeared to have peaked at 30 minutes but declined to a level higher than basal at 1 hour. No difference in TSH response was observed between the 2 treatments. Serum T4 response to TRH was reduced in the copper-deficient as compared to the adequate rats at all time intervals. After 2 hours a slight elevation was observed in the controls, but marked elevations in T4 were observed in both treatments at 4 hours. This reduction in T4 levels could be due to an impaired T4 synthesis or release in copper-deficient rats.
Animals↗
High urine concentrations of basic fibroblast growth factor in dogs with bladder cancer.
Because dogs with bladder cancer often have advanced disease at the time of diagnosis, the identification and use of a tumor marker that could facilitate earlier diagnosis is a valid approach to improve prognosis. The objective of this study was to determine if urine concentrations of the proangiogenic peptide, basic fibroblast growth factor (bFGF), are high in dogs with bladder cancer compared with normal dogs and dogs with urinary tract infection. We used a commercially available enzyme-linked immunosorbent assay test kit to quantitate bFGF in the urine of 17 normal dogs, 10 dogs with urinary tract infection, and 7 dogs with locally active transitional cell carcinoma of the urinary bladder. In normal dogs, the median urine bFGF concentration was 2.23 ng/g creatinine (quartile range, 1.53 to 5.12 ng/g creatinine). The median urine bFGF concentration in dogs with urinary tract infection did not differ significantly from normal dogs. Dogs with bladder cancer had significantly higher urine bFGF concentrations than normal dogs (P < .002) and dogs with infection (P < .02). The median urine bFGF concentration in dogs with transitional cell carcinoma was 9.86 ng/g creatinine (quartile range, 7.40 to 21.63 ng/g creatinine). Six of 7 dogs with bladder cancer had urine bFGF concentrations that were up to 7.4 times the 90th percentile value for normal dogs. Only 1 of 10 dogs with infection had a urine bFGF concentration that exceeded the 90th percentile of normal. These data suggest that canine bladder cancers export bFGF, and that urine bFGF may be useful as a diagnostic tumor marker or noninvasive indicator of treatment response.
Animals↗