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241.
Anthea L. Raisis BVSc Lesley E. Young PhD Hylton B. Meire FRCR Polly M. Taylor PhD Karen J. Blissitt PhD David Marlin Pierre Lekeux PhD 《Veterinary radiology & ultrasound》2000,41(1):64-72
The purpose of the study was to determine the ability of Doppler ultrasound to detect changes in femoral blood flow during pharmacologic manipulation of arterial blood pressure. Doppler ultrasonography was performed in the femoral vessels of six halothane-anesthetized horses before and during administration of phenylephrine HCI and sodium nitroprusside. The time-averaged mean velocity and volumetric flow were calculated. The contour of the velocity waveform was assessed, and the early diastolic deceleration slope (EDDS) and pulsatility index (PI) were calculated. Administration of phenylephrine HCI resulted in increased mean aortic blood pressure (MABP) by 40% (29.3-53.0%). This caused significant decrease in cardiac output (26.8 to 13.5 l/min), femoral arterial velocity (left artery 7.20 to 4.00 cm/s; right artery 5.01 to 3.39 cm/s) and volumetric flow (left artery 556 to 221 ml/min; right artery 397 to 193 ml/min) in the femoral vessels and significant increase in systemic vascular resistance (163 to 433 dyn-s/cm5), EDDS (1a: 285 to 468: ra: 250 to 481) and PI (1a: 9.38 to 20.4; ra 17.1 to 29.1). Administration of sodium nitroprusside resulted in a decreased MABP of 27.2% (22.5-33%). This increased cardiac output (20.8 to 32.4 L/min), however, no significant changes were observed in femoral blood flow. Despite obvious changes in the waveform contour, no significant change occurred in EDDS or PI. These results suggest that Doppler ultrasound may be useful for measuring femoral blood flow in anesthetized horses. However, waveform analysis appears to be limited when multiple changes occur in central and peripheral haemodynamics. 相似文献
242.
Enrico P. Spugnini DVM Donald E. Thrall DVM PhD G. Sylvester Price DVM PhD Nicholas J. Sharp BVM PhD Karen Munana DVM Rodney L. Page DVM 《Veterinary radiology & ultrasound》2000,41(4):377-380
Twenty-nine dogs received primary radiation therapy for intracranial lesions and clinical signs suggestive of neoplasia. Presumptive diagnosis and tumor categorization was based on computed tomographic or magnetic resonance images. Meningioma was the most likely tumor type in 22 dogs and glioma or choroid plexus tumors were tentatively identified in 4 and 3 dogs, respectively. Cobalt-60 radiation was delivered in 3 Gy fractions on a daily, Monday-through-Friday basis for a total dose of 48 Gy (16 fractions) in 28 dogs; one dog received 54 Gy. Two of 29 dogs died during treatment of signs suggestive of progressive tumor growth but were included in the overall evaluation of response to treatment. Median overall survival was 250 days (range 21-804). Mild acute radiation effects on normal tissue developed and did not influence outcome in any dog. Late radiation effects could not be evaluated in this study. No significant predictive indicators were identified from the clinical or imaging data. Radiation therapy is superior to medical treatment of brain tumors in dogs with steroids, is useful for tumors that are not currently operable and may be preferable to surgical resection in dogs if the mass appears infiltrative. However, 22/29 (76%) dogs died of recurrent progressive neuropathy suggestive of tumor regrowth or progression. Thus, alternative methods for delivery of radiation to dogs with brain tumors or novel combinations of therapy should continue to undergo evaluation. 相似文献
243.
The effects of 28 and 56 days' storage at 25°, 4° and ?20°C on the microbial biomass content of four soils from tussock grasslands were studied by three biochemical procedures. Two of the procedures involved measurement of CO2 and mineral-N (Min-N) production by chloroform-fumigated and unfumigated soil, and consequent estimation of biomass C and Min-N flush respectively. In the third, adenosine 5'-triphosphate (ATP) content was determined.Patterns of CO2 production were often influenced by storage treatment. The use of fixed incubation periods for estimating the CO2 flush of fumigated soil and the steady rate of CO2 production by unfumigated soil did, however, give biomass C estimates that were generally similar to those calculated from individually determined incubation periods for each treatment and soil.Biomass C values could change significantly at all storage temperatures, but generally least at ?20°C. Storage at ?20°C was also the most suitable for retaining ATP contents, whereas 4°C was best for values of Min-N flush. Values of Min-N flush after storage of soil at ?20°C decreased significantly in two of the soils but increased in another. No storage temperature was thus satisfactory for all three indices of microbial biomass. Generally, however, 4°C was adequate for short periods, and 25°C the least suitable. 相似文献
244.
Kermit Cromack Phillip Sollins William C. Graustein Karen Speidel Allen W. Todd Gody Spycher Ching Y. Li Robert L. Todd 《Soil biology & biochemistry》1979,11(5):463-468
Fungal mats of Hysterangium crassum (Tul. and Tul.) Fischer occupied a mean of 9.6% of the upper 10 cm of soil developed under a 40–65 yr old stand of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Oregon. This hypogeous basidiomycete exudes large amounts of oxalic acid, some of which precipitates with Ca in microscopic crystals of calcium oxalate, resulting in a mean CaC2O4 content of 82g m?2 for the entire soil. Soil oxalate concentration was significantly greater within fungal mats (P < 0.01) and soil pH was significantly lower (P < 0.01) than in soil adjacent to mats. The quantity of Ca present as CaC2O4 is 0.5 the amount of exchangeable Ca in the soil and exceeds the mass of Ca lost annually in runoff. Scanning electron micrographs show intense chemical weathering, attributable to oxalate attack, in the immediate vicinity of hyphae. X-ray diffraction patterns of clay indicate bulk weathering is more intense within the fungal mats than in adjacent uncolonized soil. 相似文献
245.
Acetyle reduction and 15N studies showed that the addition of sulfate to flooded soil with rice straw enhanced N2 fixation. The extent of the enhancement was dependent on the sulfate concentration. Sulfate also increased the population of SO42? reducing bacteria and was completely reduced to sulfide by those microorganisms. Purified cultures of soil isolates were capable of C2H2 reduction. Based on this evidence, SO42? reducing bacteria were considered responsible for the increase in N2 fixation but only 1–2 mg N2 were fixed g1? SO42? reduced. We conclude that the contribution of SO42? reducing bacteria to the total N2 fixation in flooded soil is unimportant. 相似文献
246.
Consumer perception versus scientific evidence of farmed and wild fish: exploratory insights from Belgium 总被引:2,自引:2,他引:0
Wim Verbeke Isabelle Sioen Karen Brunsø Stefaan De Henauw John Van Camp 《Aquaculture International》2007,15(2):121-136
The increasing number of marketable fish being supplied from aquaculture is a response to the increasing demand for healthy
food and is filling the gap left by depleting natural fish stocks. Little is known about the awareness and perception of the
consumer in terms of farmed fish versus fish from capture fisheries. The consumer's subjective point of view is of overriding
importance for the production system and product acceptance as well as for future market success. In this paper consumer perception
in Belgium is explored and compared against scientific evidence of farmed versus wild fish. Primary data were collected through
a consumer survey (April 2003) and focus group discussions (May 2004) with Belgian consumers. The majority of the consumer
sample reported no perceived differences between farmed versus wild fish. However, mean perception scores were slightly in
favour of wild fish on the attributes taste, health and nutritious value, in particular among consumers aged 55 years and
older. The availability of farmed fish was perceived to be better than that of wild fish, while the consumer's perception
of safety did not differ between farmed and wild fish. The focus group discussions indicated that consumers’ opinions and
beliefs about farmed fish are mainly based on emotion and image transfer from intensive terrestrial livestock production rather
than on awareness and factual knowledge of aquaculture.
相似文献
John Van CampEmail: |
247.
248.
Hypophosphatemia 总被引:2,自引:0,他引:2
S. Dm Forrester DVM MS Karen J. Moreland DVM 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》1989,3(3):149-159
Severe hypophosphatemia (i.e., serum phosphorus concentration below 1 mg/dl) occurs infrequently in veterinary patients. It is most often associated with diabetic ketoacidosis in small animals. Phosphate is necessary for the production of 2,3 diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP); both are important for normal cellular metabolism. Consequences of severe hypophosphatemia may include hemolytic anemia, seizures, altered mentation, cardiomyopathy, and skeletal muscle weakness. Parenteral phosphate therapy is necessary in most cases of severe hypophosphatemia. 相似文献
249.
250.
Karen E.N. Hayes DVM MS O.J. Ginther VMD PhD 《Journal of Equine Veterinary Science》1989,9(6):316-318
Unsolicited reports of estrous behavior in mares thought to be pregnant were received from owners or caretakers of Arabian mares. Estrous behavior was confirmed and mares were examined for pregnancy. Gender of the conceptus was determined at foaling in 11 mares in which estrous behavior was confirmed while an apparently viable, ultrasonically normal-appearing conceptus was present. In 9 mares in which the day of ovulation was known (Day 0), the estrous behavior occurred on Day 12, 13 or 14 (5 mares), Day 18 or 20 (2 mares), Day 40 (1 mare) and Day 60 (1 mare). In another study, 55 pony mares were observed for estrous behavior every 3 days for 20 minutes during Days 11 to 40. Estrous behavior was observed in 1 mare (2%) on Day 24. Combined for the 2 studies, the incidence of a female conceptus (12/12) was greater (P<0.01) than the incidence of a male conceptus (0/12) in mares that exhibited estrous behavior. 相似文献