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1.
Tumor biopsy samples from 25 Floridian and 15 Hawaiian green turtles (Chelonia mydas) with spontaneous green turtle fibropapillomatosis (GTFP) and from 27 captive-reared green turtles with experimentally induced GTFP were examined microscopically to differentiate the histologic features that result from GTFP pathogenesis and those that result from incidental factors that may vary according to geographic region. Common histologic features for spontaneous and experimentally induced tumors included fibroblast proliferation in the superficial dermis, epidermal acanthosis and hyperkeratosis, epidermal basal cell degeneration with dermal-epidermal cleft formation, spinous layer degeneration with intraepidermal vesicle and pustule formation, and ulceration. Visceral tumors, found in eight of 10 (80%) free-ranging turtles with cutaneous disease that were examined after death, had extensive interstitial fibrous proliferation. The presence of spirorchid trematode eggs and associated foreign body granulomas, common secondary findings within spontaneous tumors, varied by geographic location, and these findings were not observed in experimentally induced tumors. Eosinophilic intranuclear inclusions and intranuclear herpesvirus-associated antigen immunoreactivity were found in 18 of 38 (47%) experimentally induced cutaneous tumors and nine of 119 (7.5%) spontaneous tumors from Floridian but not Hawaiian turtles. The possible involvement of GTFP-associated herpesvirus in the pathogenesis of epidermal degenerative changes and GTFP pathogenesis is discussed.  相似文献   
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Growth, feed conversion and survival were determined for juvenile Macrobrachium rosenbergii held in tanks under semi-controlled environmental conditions. Feeding trials incorporated water-stable diets at three levels of protein (15, 25 and 35%). The principal protein source combinations consisted either of soybean and tuna meal, or of soybean, tuna and shrimp meal. In a 244-day comparison of these diets, higher protein content produced larger prawns (P < 0.01), but differences between sources were not significant. No significant differences existed between feed conversion ratios (range 1.36–1.72) or percentage survival (range 90.3–93.6%). Trials of several other diets were also conducted, including soybean and Tilapia meal, and copra and Tilapia meal (25% protein level) as principal protein source combinations. After 167 days on these diets, growth was inferior to that obtained with soybean and tuna meal or soybean, tuna and shrimp meal combinations. No significant differences existed between feed conversion ratios or percentages of survival.For the 244 days, a control group of prawns received no formulated diet. Growth and survival in this group during the first 110 days suggested that naturally occurring algae contributed substantially to the prawns' nutrition.Mean prawn length after 244 days on the best diet (35% protein from soybean and tuna meal) was 73 mm, and growth rate was equivalent to that achieved under pilot pond conditions.  相似文献   
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Bovine papillomavirus (BPV) types 1 (BPV-1) and 2 (BPV-2) are causally associated with the development of equine sarcoid tumors. Recurrence rates after surgical excision of sarcoids are estimated to be 30%–40%. We hypothesized that the presence of BPV DNA in histologically tumor-free surgical margins of sarcoids is associated with risk of recurrence, and increased quantity of BPV DNA is associated with increased risk of recurrence. Formalin-fixed sarcoids classified as “completely excised” histologically were obtained from two institutions. A total of 25 tumors were included, eight of which recurred within 1 year of excision. Qualitative and quantitative polymerase chain reaction (PCR) tests for detection of BPV-1 and BPV-2 were performed on neoplastic tissue and tumor-free surgical margins in formalin-fixed paraffin-embedded biopsy specimens following DNA extraction. Bovine papillomavirus-1 was found in all tumor samples and in histologically “clean” margins of 21 samples, whereas BPV-2 was found in only two tumor samples. Although quantitative PCR was more sensitive than qualitative PCR in detecting BPV DNA in surgical margins, there was no significant difference in the presence of BPV-1 or BPV-2 DNA in margins of tumors that recurred versus those that did not recur for either test. Although this study is limited by sample size, our results suggest that PCR analysis of surgical margins for BPV DNA is not a reliable method to predict equine sarcoid recurrence after resection.  相似文献   
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Nitrous oxide (N2O) release by Streptomyces nitrosporeus in a sandy loam soil as affected by pO2, pH and amount of easily decomposable organic carbon In model experiments under defined conditions (80%WHC, 300 μg nitrate-N g?1 dry soil, 30°C) the effect of pO2, pH and addition of easily decomposable organic matter on nitrous oxide production by Streptomyces nitrosporeus DSM 40023 from a sterilized sandy loam soil was studied. This streptomycete reduces nitrate to N2O but not to N2. The strain was inoculated into a sterilized sandy loam soil (pH 6), enriched with nitrate and incubated at approximately 20 and 10% (v/v) O2 for 26 days. In another series of experiments the pH was increased with NaOH-solution up to pH 7 or the soil was enriched with pulverized leaves (1%) to increase mineralization activity and the demand for electron acceptors. In the headspace the concentration of O2, CO2 and N2O was analysed by GC. The soil concentration of NO3?, NO2? and NH4+ was measured as well as the pH value. The population density was determined by the plate count method. At a decreased oxygen concentration of about 2.5% (v/v) in the headspace, S. nitrosporeus increased the release of N2O. In the experiments with an initial oxygen concentration of approximately 20% (v/v) this threshold of about 2.5% /(v/v) O2 was hardly reached and consequently only little N2O was produced. Apparently, S. nitrosporeus uses O2 in preference to nitrate, which is characteristical of nitrate respiration. A pH increase from pH 6 to 7 reduced the lag phase significantly and increased the rate of oxygen consumption, CO2 release and N2O production. Maximum nitrous oxide production was reached after 13 days. The result indicated that streptomycetes like S. nitrosporeus may use nitrate alternativly to O2 to maintain energy conservation (ATP synthesis) with the release of N2O. So far, nothing is known about the role of streptomycetes in contributing to N2O production in natural soils.  相似文献   
6.
Development of heavy-metal deposition by precipitation in West Germany. 1. Lead and cadmium Between 1984 and 1993 the deposition of Pb and Cd with bulk precipitation was measured on 25 open field sites in 4 German federal states. The absolute amount of Pb and Cd deposition varies according to field sites and annual precipitation. In all studied areas, however, Pb deposition via bulk precipitation decreased significantly during the observation period. Considering all research areas under study, the average Pb deposition with bulk precipitation fell from 142 g ha?1 in 1984 to 31 g ha?1 in 1993 (r = ?0.934***). This decrease in Pb deposition correlates with the prognosticated decline in Pb emissions that occurred in Germany during the same time period owing to the introduction of unleaded motor fuels in 1984. Average Cd deposition on all research stations fell from 3.4 g ha?1 in 1984 to 2.0 g ha?1 in 1993 (r = ?0.900***). However, in contrast to Pb, the reduction of Cd deposition was significant only at 11 of 25 research stations. The reduction in Cd deposition with precipitation is substantially lower than the reduction in Cd emissions prognosticated.  相似文献   
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Twelve horses with traumatic arthritis were treated with intraarticular injection of hyaluronic acid mixed with cortisone and the results compared with 6 horses treated only with cortisone. There was a significantly better improvement in the group injected with a mixture of hyaluronic acid and cortisone. Further studies have given the same results in traumatic arthritis in horses if hyaluronic acid alone is injected.After injection of hyaluronic acid a large number of granulated monocytes appeared in the synovial fluid, but no inflammatory signs were observed. It is possible that this macrophage invasion is instrumental in producing improvement in the condition of the joint. The injected hyaluronic acid may also adhere to the surface of articular cartilage producing an “clastic cushion” protecting the cartilage surface.Experimental mechanical damage was also inflicted on the surface of articular cartilage in dogs and monkeys, and smoother healing was achieved if hyaluronic acid was injected into the joints after the damage.Injections of hyaluronic acid seem to be of value in treating traumatic arthritis or similar conditions.  相似文献   
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The mixing of polymers and nanoparticles is opening pathways for engineering flexible composites that exhibit advantageous electrical, optical, or mechanical properties. Recent advances reveal routes to exploit both enthalpic and entropic interactions so as to direct the spatial distribution of nanoparticles and thereby control the macroscopic performance of the material. For example, by tailoring the particle coating and size, researchers have created self-healing materials for improved sustainability and self-corralling rods for photovoltaic applications. A challenge for future studies is to create hierarchically structured composites in which each sublayer contributes a distinct function to yield a mechanically integrated, multifunctional material.  相似文献   
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