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161.
Immune exclusion of Haemonchus contortus larvae in sheep: dose dependency, steroid sensitivity and persistence of the response 总被引:2,自引:0,他引:2
F Jackson H R Miller G F Newlands S E Wright L A Hay 《Research in veterinary science》1988,44(3):320-323
Naive and immune sheep, treated with anthelmintic, challenged directly into the abomasum and killed 48 hours later were used to examine the steroid sensitivity, persistence and dose dependency of immune mechanisms which result in the failure of incoming Haemonchus contortus larvae to establish (immune exclusion). Immune exclusion was almost totally abolished by corticosteroid treatment, the mean percentage of larvae establishing in the mucosa of immune sheep was 1.4 per cent of the challenge infection whereas in those treated with dexamethasone it was 24.4 per cent and in naive sheep 27.3 per cent. Immune animals challenged after seven and 42 days without antigenic experience excluded more than 90 per cent of the challenge larvae from their mucosae, whereas those challenged after 84 days without antigenic experience were as susceptible as naive animals. Immune exclusion was dose dependent, animals challenged with 10(6) and 10(5) larvae excluded 93 per cent and 82.5 per cent of the challenge dose whereas those challenged with 10(4) larvae failed to exclude larvae. 相似文献
162.
Research we have conducted over the past several years relative to agricultural application of remote sensing is reviewed. In addition, new data are presented from recent experiments reported here for the first time.The subjects treated are soil moisture, evaporation, irrigation scheduling, and crop yield estimation. The analyses indicate that we have the technology at hand to successfully integrate remote sensing techniques into agricultural operations designed to enhance production via intelligent water management.Avenues for additional fruitful research are indicated. 相似文献
163.
164.
J. K. Dunn D. E. Bostock M. E. Herrtage K. F. Jackson M. J. Walker 《The Journal of small animal practice》1993,34(7):325-331
This paper describes the clinical and pathological features of 11 dogs with insulin-secreting tumours of the pancreas. All the dogs showed episodic weakness or collapse. The diagnosis was made on fasting plasma glucose and serum insulin concentrations, the insulimglucose ratio, and the results of an intravenous glucose tolerance test. Ten of the dogs had exploratory laparotomy, and partial pancreatectomy was performed in nine of the cases. One case was euthanased at surgery because of widespread metastases. The tumours were graded histologically and the results compared with the time to recurrence of clinical signs and postoperative survival time. Postoperative survival time for dogs which died or were euthanased as a direct result of tumour recurrence, and time to recurrence of clinical signs were calculated from actuarial survival curves. The median time to recurrence of clinical signs after surgery was 12 months (range from four to 16 months; mean time to recurrence of clinical signs 12 months). Two cases died of unrelated disease, without recurrence of hypoglycaemic signs. The median postoperative survival time was 14 months (range 10 to 33 months; mean survival time 15 months). There is a suggestion that tumours with a high mitotic count carried a worse prognosis. 相似文献
165.
Thirty foals of mixed breeding, from two consecutive years, were used in two 120-d experiments to evaluate the effects of supplemental feeding (creep feed) on growth in nursing foals. At 10 d postpartum, foals were randomly assigned either to a creep-fed group (CF) or an unsupplemented group (NCF). Initial measurements of body weight (BW), height at the withers (WH), third metatarsal length (MtIII) and third metacarpal length (McIII) were made at 10 d of age and at 30-d intervals thereafter. Medial and lateral cortical peak values for radiographic bone density, cortical width and cortical area at the midpoint of the third metacarpal were used to assess bone quality. Creep feed containing National Research Council (NRC, 1978) recommended levels for all nutrients was offered at 1.5% of BW per day. When compared with unsupplemented foals, supplemented foals had greater gains in BW (P less than .05), in WH (P less than .10) and in MtIII (P less than .05). Mean gains during the trial in BW, WH, MtIII and McIII for the CF foals were 133.3 kg, 22.8 cm, 2.1 cm and 1.9 cm and for the NCF foals were 117.6 kg, 21.2 cm, 1.5 cm and 1.9 cm, respectively. The mean value for the lateral cortical peak was slightly lower (P less than .10) for the CF foals. No differences (P greater than .10) were observed for the medial cortical peak, cortical width or cortical area of the third metacarpal. The results of this study indicate that a creep feeding program that supplies NRC-recommended nutrient levels can increase the rate of skeletal growth with little decrease in quality of bone. 相似文献
166.
167.
Uterine irrigation was carried out in eight Welsh pony mares using 50 ml of chlorhexidine gluconate solution diluted to give active ingredient concentrations of 0.25 per cent to 2 per cent. Treatment was repeated up to twice in mares showing no adverse effects and irritancy of treatment judged on clinical symptoms and uterine biopsy. Results indicated the inadvisability of using a higher concentration than 0.25 per cent. Three daily applications of a diluted surgical scub solution containing 2 per cent chlorhexidine gluconate to the penis of an arab stallion failed to produce symptoms or irritation. An in vitro minimum inhibitory concentration test performed with the contagious equine metritis organism confirmed its high sensitivity to both chlorhexidine gluconate preparations. 相似文献
168.
Observations on the egg output resulting from continuous low level infections with Ostertagia circumcincta in lambs 总被引:1,自引:0,他引:1
Faecal egg counts were determined twice weekly for two groups of four-month-old worm free cross Suffolk lambs experimentally infected with 100 and 320 Ostertagia circumcincta larvae, five times per week for 20 weeks. The group mean egg count in both groups rose to a maximum of approximately 500 eggs per gram during weeks 12 to 14 and had fallen to less than half of that value at slaughter. There was no statistical difference in egg output between these two groups or between them and a comparable group of lambs receiving 4000 Ostertagia circumcincta larvae per day. No significant changes in live weight gain or serum pepsinogen levels were observed in the lambs given 100 and 320 larvae per day. 相似文献
169.
170.
This study concerns the vestigial metacarpal and metatarsal bones, so called splint bones. The soft tissues, which stabilize the splint bones were carefully examined. The palmar metacarpal/plantar metatarsal fascia, the metacarpal/metatarsal interosseous ligaments and the fibres, which exit distally from the splint bone, were examined in depth. Cadaveric distal limbs were collected from 5 slaughtered or euthanized horses. The legs were examined both, microscopically and macroscopically. The palmar metacarpal/plantar metatarsal fascia is a very stable structure, which connects the splint bone with its environment. The connection between splint and McIII/MtIII, established through the metacarpal/ metatarsal interosseous ligaments, showed impressive differences between specimens examined. Macroscopic examination of the soft tissue in the distal region showed a band structure, which originates from the distal end of the splint bone and extends in dorsal and distal direction towards the proximal sesamoid bone. 相似文献