Morphologic Effects of Experimental Distention of Equine Small Intestine   总被引：1，自引：0，他引：1  

DOUGLAS ALLEN Jr  .  dvm  ms  Diplomateacvs  NATHANIEL A. WHITE II dvm  ms  Diplomateacvs DAVID E. TYLER dvm  PhD  Diplomateacvp 《Veterinary surgery : VS》1988,17(1):10-14

The morphologic effects of induced intraluminal hydrostatic pressures (IHPs) of 0, 9, and 18 cm H₂O were evaluated in 33 isolated equine jejunal segments. Fifteen segments were distended with Tyrode's solution for 1 hour and nine segments for 4 hours. Tyrode's solution was added as needed to maintain the prescribed pressures. Nine other segments were left undisturbed for 4 hours after the initial distention period. On decompression of the intestinal segments, progressive peristaltic contractions resumed in all segments. Evaluation of intestinal sections by light microscopy and transmission electron microscopy showed edema of the villi and submucosa and separation of the epithelial cells adjacent to the basement membrane in all segments. The epithelial cell necrosis found in ischemic intestine was not seen. This study indicates that the necrosis found at the villous tips in distended sections of small intestine remote from the site of obstruction cannot be reproduced by IHP increases of 4 hours duration.  相似文献   

Ocular toxicity and distribution of subconjunctival and intravitreal rapamycin in horses     

L. C. DOUGLAS  N. Y. YI  J. L. DAVIS  J. H. SALMON  B. C. GILGER 《Journal of veterinary pharmacology and therapeutics》2008,31(6):511-516

In vitro photosensitivity of rapamycin (RAPA) and ocular toxicity and distribution of intravitreal and subconjunctival RAPA was evaluated in normal horses. RAPA (2.5 mg, 5 mg, and 10 mg) was placed in 10 mL of PBS and maintained in a water bath at 37 °C, kept in the dark or subjected to room light, and sampled for up to 3 months for RAPA levels. Six normal adult horses received either 5 mg (n = 2) or 10 mg (n = 2) of RAPA intravitreally or 10 mg (n = 2) subconjunctivally. Ophthalmic exams and electroretinography (ERG) were performed prior to injection and on days 1, 7, 14, and 21 post‐injection. Eyes were enucleated and samples were collected for RAPA concentrations and histopathology. No difference in light vs. dark RAPA concentrations was observed, suggesting a lack of RAPA phototoxicity. No evidence of ocular toxicity was noted on ophthalmic examination or histopathology. RAPA was not detected intraocularly 7 days post‐injection in eyes receiving subconjunctival RAPA, but was detected in the vitreous at 21 days post‐injection. Drug could be detected in both the aqueous and vitreous humor after intravitreal injection. Further study is needed to determine the efficacy of intravitreal RAPA.  相似文献   

The production and utilization of lucerne in New Zealand   总被引：1，自引：0，他引：1  

J. A. DOUGLAS 《Grass and Forage Science》1986,41(2):81-128

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A Case Study of Urban Redevelopment through Federal Funding     

DOUGLAS MONTGOMERY 《Growth and change》1974,5(1):41-46

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The toxicity of Castanospermum australe seeds for cattle     

RA McKENZIE  KG REICHMANN  CK DIMMOCK  PJ DUNSTER  JO TWIST 《Australian veterinary journal》1988,65(6):165-167

Two calves given a mean of 16.1 g and 16.4 g ripe Castanospermum australe seeds/kg body weight daily for 13 and 16 days respectively developed haemorrhagic gastroenteritis. The first calf died. The second calf had mild myocardial degeneration and necrosis and mild nephrosis at necropsy. Two calves given a mean of 16.8 g unripe C. australe seeds/kg body weight daily for 18 days remained clinically normal and had mild gastritis at necropsy. The activity of alpha-glucosidase was reduced in the mononuclear cells of peripheral blood and in skeletal muscle. This was attributed to the presence of the indolizidine alkaloid, castanospermine, in the seeds. The toxin causing the gastroenteritis and other lesions is unknown.  相似文献   

Structure of a silty soil in relation to management   总被引：3，自引：0，他引：3  

J. T. DOUGLAS  M. G. JARVIS†  K. R. HOWSE‡  M. J. GOSS‡ 《European Journal of Soil Science》1986,37(1):137-151

In the United Kingdom silty soils have been classified as unsuitable for direct drilling since these soils may produce seed-beds that are inadequate for satisfactory crop emergence. This judgement was based on problems encountered in the first 2–3 yr of direct drilling as well as on an appreciation of soil physical properties. Longer-term experimentation (10 yr) has indicated that, subsequent to that initial period, soil conditions after zero-tillage are not a major limitation to growth of autumn-sown cereals. This eventual parity between simplified and conventional tillage can be attributed largely to improvement in the surface of direct-drilled land. In the tenth experimental year this layer comprised more strongly developed aggregates, of greater stability, than those from the annually ploughed soil. Porosity and soil strength measurements did not indicate that root growth would be severely restricted below this depth. When this soil was wet in winter it was weak and relatively unstable and so it would most likely be unsuitable for sequential direct drilling of spring-sown crops. At the same site soil that had been continuously under grass throughout the same 10 yr period developed better structure than that in the arable area, in part because of a greater earthworm population and an increased organic matter accumulation. In any subsequent change to arable usage this improved structure would best be conserved by avoiding soil inversion and using direct drilling or some other simplified method of cultivation.  相似文献   

The first case of genetically confirmed monozygotic twinning in the dog          下载免费PDF全文

CJ Joonè  KGM De Cramer  JO Nöthling 《Reproduction in domestic animals》2016,51(5):835-839

Monozygotic twinning has not previously been genetically confirmed in the dog. This case report describes the finding of two viable male monozygotic foetuses within one placental site during caesarean section. Their umbilical cords attached to a single placenta. Genetic profiling using a total of 38 microsatellite markers, as well as amelogenin and SRY for sex determination, revealed identical DNA profiles, whether derived from blood or tissue (buccal swabs) samples. To the best of our knowledge, this is the first report of monozygotic twinning in the dog confirmed using DNA profiling.  相似文献   

A COMPARISON OF THE 'VIBRAJET' NOZZLE AND A FAN JET FOR OVERALL APPLICATION OF BIPYRIDYL HERBICIDES     

G. DOUGLAS 《Weed Research》1968,8(1):14-27

Summary. The 'Vibrajet' nozzle is designed to produce relatively large droplets with 'low drift' characteristics. This system was evaluated for the overall application of paraquat, diquat and morfamquat in a number of agricultural situations in comparison with a fan jet. The biological efficiency achieved with the 'Vibrajet' nozzle was of the same order as that of the fan jet at the rates of application of the herbicides currently recommended in the United Kingdom. Five variables which affect the field performance of a spray system were investigated: volume of spray applied, concentration of wetter in the spray, rate of chemical applied, spray pressure and size of orifice. Changes in these factors made little improvement to the biological efficiency of the 'Vibrajet' nozzle.
Comparaisnn de la buse 'Vibrajet' et d'une bitse pinccau pom Vapplication generalisee des herbicides bipyridiliques  相似文献   

Bottom-up forcing and the decline of Steller sea lions (Eumetopias jubatus) in Alaska: assessing the ocean climate hypothesis   总被引：1，自引：0，他引：1  

ANDREW W. TRITES  ARTHUR J. MILLER  HERBERT D. G. MASCHNER  MICHAEL A. ALEXANDER  STEVEN J. BOGRAD  JOHN A. CALDER  ANTONIETTA CAPOTONDI  KENNETH O. COYLE  EMANUELE DI LORENZO  BRUCE P. FINNEY  EDWARD J. GREGR  CHESTER E. GROSCH  STEVEN R. HARE  GEORGE L. HUNT  JAIME JAHNCKE  NANCY B. KACHEL  HEY‐JIN KIM  CAROL LADD  NATHAN J. MANTUA  CAREN MARZBAN  WIESLAW MASLOWSKI  ROY MENDELSSOHN  DOUGLAS J. NEILSON  STEPHEN R. OKKONEN  JAMES E. OVERLAND  KATHERINE L. REEDY‐MASCHNER  THOMAS C. ROYER  FRANKLIN B. SCHWING  JULIAN X. L. WANG  ARLISS J. WINSHIP 《Fisheries Oceanography》2007,16(1):46-67

Declines of Steller sea lion (Eumetopias jubatus) populations in the Aleutian Islands and Gulf of Alaska could be a consequence of physical oceanographic changes associated with the 1976–77 climate regime shift. Changes in ocean climate are hypothesized to have affected the quantity, quality, and accessibility of prey, which in turn may have affected the rates of birth and death of sea lions. Recent studies of the spatial and temporal variations in the ocean climate system of the North Pacific support this hypothesis. Ocean climate changes appear to have created adaptive opportunities for various species that are preyed upon by Steller sea lions at mid‐trophic levels. The east–west asymmetry of the oceanic response to climate forcing after 1976–77 is consistent with both the temporal aspect (populations decreased after the late 1970s) and the spatial aspect of the decline (western, but not eastern, sea lion populations decreased). These broad‐scale climate variations appear to be modulated by regionally sensitive biogeographic structures along the Aleutian Islands and Gulf of Alaska, which include a transition point from coastal to open‐ocean conditions at Samalga Pass westward along the Aleutian Islands. These transition points delineate distinct clusterings of different combinations of prey species, which are in turn correlated with differential population sizes and trajectories of Steller sea lions. Archaeological records spanning 4000 yr further indicate that sea lion populations have experienced major shifts in abundance in the past. Shifts in ocean climate are the most parsimonious underlying explanation for the broad suite of ecosystem changes that have been observed in the North Pacific Ocean in recent decades.  相似文献   

SCINTIGRAPHIC EVALUATION OF THE PROXIMAL METACARPAL AND METATARSAL REGIONS IN CLINICALLY SOUND HORSES     

JO S. WEEKES  RACHEL C. MURRAY  SUE J. DYSON 《Veterinary radiology & ultrasound》2006,47(4):409-416

In recent years, pain arising from the proximal metacarpal and metatarsal regions has become well recognized as a cause of lameness and various disease entities have been identified. However, our knowledge of normal patterns of radiopharmaceutical uptake is limited, making interpretation of images problematic. It is therefore important to characterize normal patterns of radiopharmaceutical uptake at specific sites to ensure valid interpretation of images in clinical cases with subtle lesions. The purpose of this study was to describe the pattern of radiopharmaceutical uptake in the proximal metacarpal and proximal metatarsal regions in clinically sound horses. Scintigraphic images from 64 clinically normal horses were evaluated. All the images were assessed subjectively. The lateral, dorsal, and plantar scintigraphic images were assessed qualitatively using horizontal line profiles through the proximal metacarpal and proximal metatarsal regions. Mean ratios of radiopharmaceutical uptake were calculated from three regions of interest sited over the proximal metacarpal and proximal metatarsal regions and a reference site. In 78% of forelimbs the peak of radiopharmaceutical activity was at the dorsal to central portion of the proximal metacarpal region. Seventy-five per cent of the dorsal plane profiles of activity were symmetrical, with the highest peak over the medial to central portion of the proximal metacarpal region. In 80% of hindlimb lateral images the peak radiopharmaceutical activity was at the central to plantar aspect of the proximal metatarsal region. All (100%) plantar image profiles of activity were symmetrical, with the highest peak being over the lateral portion of the proximal metatarsal region. There was no significant left and right variation between sites for mean ratios on the lateral and dorsal images of the proximal metacarpal region. However, using lateral images the mean ratios from all regions of the right proximal metatarsal were greater than left (dorsal P = 0.003, plantar P < 0.0001 and whole proximal metatarsal, P = 0.0006). There was no significant variation in mean ratios between left and right on plantar images. However, the mean ratio for the lateral proximal metatarsal region was significantly greater than for the medial proximal metatarsal regions (P < 0.0001). There was no significant effect of age. Left/right symmetry of radiopharmaceutical uptake was shown in the proximal metacarpal region. However, there was a significant difference between left and right proximal metatarsal regions. There was higher radiopharmaceutical uptake in the right proximal metatarsal region than the left, which agrees with previous studies of the tarsal and metatarsophalangeal joints. There were differences in the pattern of radiopharmaceutical uptake between the forelimbs and hindlimbs. In the forelimbs maximum radiopharmaceutical uptake was located at the dorsal to central portion of the proximal metacarpal region in the lateral image, with peak activity over the medial to central portion of the proximal metacarpal region on dorsal images. In the hindlimbs the maximum radiopharmaceutical uptake was at the central to plantar aspect of the proximal metatarsal region in the lateral image, with peak activity over the lateral portion of proximal metatarsal region on plantar images. The results of this study support the hypothesis that there would be a standard pattern of radiopharmaceutical uptake across the proximal metacarpal and l metatarsal regions, but the pattern of uptake observed would be different in the proximal metacarpal region compared with the proximal metatarsal region. There was left/right symmetry of radiopharmaceutical uptake in the proximal metacarpal region. However, there was a significant difference between left and right proximal metatarsal regions, with higher radiopharmaceutical uptake in the right. There was no variation of radiopharmaceutical uptake pattern with age.  相似文献