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31.
Two cases of temporohyoid osteoarthropathy (THO) in young Australian horses are described. The pathogenesis of THO is yet to be fully elucidated, but current theories include extension of infection from otitis media or interna to the temporohyoid joint or a primary but non‐infectious degenerative condition within the temporohyoid joint. The young age of the horses and the unilateral distribution suggested an infectious aetiology. Both horses partially responded to treatment with broad‐spectrum antimicrobial and anti‐inflammatory drugs with concurrent management of ulcerative keratitis. The management of violent head shaking in one horse included the administration of gabapentin, an anticonvulsant known to have antihyperalgesic effects and reduce neuropathic pain.  相似文献   
32.
SUMMARY A brief history of food safety in Australia in the context of the development of scientific knowledge is presented. Australia's food and food commodity residue and contamination surveillance and monitoring programs are outlined. Although chemical residues are perceived as a major health risk by the general community, the risk of food causing illness or death because of chemical residues is low. The major threat to human health from food is microbiological contamination, in terms of deaths, sickness and economic loss. The emerging influences in food safety are scientific and technical developments, deregulation, social and demographic factors, and the media. The risk of disruption of domestic and export markets by food safety issues is considerable. The emergence of international standards for food production and processing will enable commercial contractual arrangements to minimise the frequency of disruptive food safety incidents.  相似文献   
33.
Levels of luteinizing hormone (LH), follicle stimulating hormone (FSH), progesterone and estradiol-17 beta were measured in five Polled Hereford cows. Blood samples were collected once or twice daily for 5 d, then every 6 h from 1 d before weaning (d 28 to 38 postpartum) until 10 d after the second postweaning estrus. Blood samples were again collected at daily intervals until the third postweaning estrus. All cows exhibited estrus within 4 d after weaning, a second estrus 8 to 10 d after the first and a third estrus 16 to 23 d after the second. All cows had peaks in serum concentrations of LH during the first (22.6 to 81.7 ng/ml) and second (4.4 to 149.0 ng/ml) postweaning estrus. Mean levels of LH in serum during the peak and the area under the LH curve during the first and second postweaning estrus did not differ. Serum levels of LH and FSH during the first 4 d of the short cycle did not differ from LH and FSH levels the first 4 d of the subsequent normal cycle. Levels of LH in serum for 4 d before the first LH surge, associated with the first postweaning estrus, did not differ from levels of LH found 4 d before the second Lh surge, associated with the second postweaning estrus. However, serum levels of FSH during the 4 d before the first ovulatory LH surge were lower (P = .05) than those observed during the 4-d period before the second ovulatory surge of LH. Progesterone levels were similar the first 6 d after the first and second estrous periods, but were lower after d 6 of the first (short) cycle than after d 6 of the second (normal) cycle. Estradiol peaks of 1.2 to 2.8 pg/ml were detected during the first postweaning estrus and 1.4 to 12.5 pg/ml during the second postweaning estrus, but due to the variability among cows mean levels of estradiol during first estrus did not differ from second estrus. These data agree with previous reports that postpartum anestrous cows had short cycles if they exhibit estrus in response to weaning. The early decline of progesterone after the first estrus apparently did not stem from lack of LH in serum, but the lower levels of FSH observed before this first ovulation may have been an important factor contributing to the reduced life span of the subsequent corpus luteum.  相似文献   
34.
Central Greenland ice cores provide evidence of abrupt changes in climate over the past 100,000 years. Many of these changes have also been identified in sedimentary and geochemical signatures in deep-sea sediment cores from the North Atlantic, confirming the link between millennial-scale climate variability and ocean thermohaline circulation. It is shown here that two of the most prominent North Atlantic events-the rapid warming that marks the end of the last glacial period and the Bolling/Allerod-Younger Dryas oscillation-are also recorded in an ice core from Taylor Dome, in the western Ross Sea sector of Antarctica. This result contrasts with evidence from ice cores in other regions of Antarctica, which show an asynchronous response between the Northern and Southern Hemispheres.  相似文献   
35.
36.
Interfacially active block copolymer amphiphiles have been synthesized and their self-assembly into micelles in supercritical carbon dioxide (CO2) has been demonstrated with small-angle neutron scattering (SANS). These materials establish the design criteria for molecularly engineered surfactants that can stabilize and disperse otherwise insoluble matter into a CO2 continuous phase. Polystyrene-b-poly(1,1-dihydroperfluorooctyl acrylate) copolymers self-assembled into polydisperse core-shell-type micelles as a result of the disparate solubility characteristics of the different block segments in CO2. These nonionic surfactants for CO2 were shown by SANS to be capable of emulsifying up to 20 percent by weight of a CO2-insoluble hydrocarbon into CO2. This result demonstrates the efficacy of surfactant-modified CO2 in reducing the large volumes of organic and halogenated solvent waste streams released into our environment by solvent-intensive manufacturing and process industries.  相似文献   
37.
The benefits and application of thoracoscopy with selective ventilation, as an adjunct to thoracotomy, in facilitating pleural exploration and lung lobectomy in two dogs are presented. Similar thoracoscopic-assisted procedures are commonly used in human patients because there is better exposure and they are technically less demanding than thoracoscopy alone, while causing less postoperative morbidity than conventional thoracotomy. There are no previous reports of thoracoscopic-assisted surgery in the veterinary literature. In the cases described, thoracoscopic-assisted mini-thoracotomy was an effective, minimally-invasive approach for ipsilateral hemithorax exploration and lung lobectomy.  相似文献   
38.
Tracheal mucociliary clearance was determined in horses by measuring the rostrad transport of the radiopharmaceutical 99mtechnetium-sulphur colloid following deposition on the tracheal epithelium by intratracheal injection. The effects of head position (head elevated to normal standing position vs head lowered) and of accumulated purulent secretions on tracheal mucociliary clearance were evaluated for the first time in the horse. In normal horses tracheal mucociliary clearance was greatly accelerated by lowering the head so that the cranial trachea was lower than the caudal trachea. Horses confined with their heads elevated for 24 hours developed an accumulation of purulent airway secretions (and associated increased numbers of bacteria) in the lower respiratory tract and showed a decrease in tracheal mucociliary clearance when compared with their previously measured rate when the lower airway contained only normal secretions. These findings have implications for management practices where horses are prevented from lowering their heads, such as transportation and cross-tying, which may therefore contribute to lower respiratory tract disease in horses.  相似文献   
39.
Percentages of normal and apoptotic parenchymal cells, fibroblasts and endothelial cells in ovine corpora lutea at 12, 24 and 36 hr following administration of a luteolytic dose of PGF2 alpha were determined and compared to percentages for identical cell types in corpora lutea removed from control ewes on days 10 (n = 5) and 12 (n = 6) postestrus. In corpora lutea obtained from control ewes greater than or equal to 95% of nuclei examined were scored normal for each of the respective cell types with no difference (P greater than .05) observed between luteal tissue obtained on days 10 and 12 postestrus. Following treatment with PGF2 alpha there were significant (P less than .05) reductions in the percentages of nuclei scored normal. Compared to controls the percentage of endothelial cell nuclei scored normal was reduced at 12 hr following PGF2 alpha-treatment; however significant reductions in percentages of parenchymal and fibroblast nuclei scored normal were not evident until 24 and 36 hr, respectively. Consistent with the concept of apoptosis, nuclear condensation and/or margination indicative of apoptosis did not occur synchronously within a given cell type: i.e., irrespective of the time point examined some cells appeared normal, whereas others had undergone nuclear condensation and/or margination. A sequence of events to explain structural and functional changes that occur during luteolysis following the interaction of PGF2 alpha with specific receptors in large steroidogenic luteal cells is discussed.  相似文献   
40.
Two hundred eighteen ewes were used in experiments 1) to develop a progesterone supplementation regimen capable of sustaining serum concentrations of progesterone at about 2.0 ng/ml for a period of 50 d (Exp. 1) and 2) to determine the effects of progesterone supplementation (d 6 to 50 after mating) on pregnancy and embryo survival rates in mated ewes (Exp. 2). In ovariectomized ewes in Exp. 1, s.c. administration of four cylindrical (9.5 x 60 mm) silastic implants, containing 20% (1.1 g) progesterone by weight, sustained mean serum concentrations of progesterone of 1.9 +/- .07 ng/ml compared with 1.03 +/- .05 ng/ml in ewes bearing two implants. In Exp. 2 each ewe (n = 159) was mated to two fertile rams at a spontaneous estrus (d 0) during mid-breeding season. Mean ovulation rate, determined on a subgroup of 46 ewes, was 1.45 +/- .05. On d 6, ewes were assigned randomly to control (two implants containing no progesterone) or progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (four implants similar to those used in Exp. 1) groups. From d 7 to 50 after mating, progesterone concentrations in serum were greater (P less than .001) in progesterone-treated (3.50 +/- .06) than in control (2.65 +/- .05) ewes. Pregnancy rates (86% and 83%) and calculated embryo survival rates (77% and 78%) were similar (P greater than .05) for the control and progesterone-treated groups, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
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