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31.
Melissa Smith Jonathon R. Dodd H. Phil Hobson Sharman Hoppes 《Journal of Exotic Pet Medicine》2013,22(3):258-264
Acquired dental disease and the formation of elodontomas are often diagnosed in sciurids. The formation of the elodontoma may be preceded by a traumatic tooth injury or other initiating factors. The degree of disease severity varies based on individual presentation and the time of detection. Maxillary elodontomas in sciurid species cause airway obstruction that can prove fatal for these obligate nasal-breathing animals. A thorough understanding of rodent dental anatomy and a complete diagnostic workup are required for diagnosis, prognosis, and surgical planning of elodontoma presentations. This article highlights 2 successful surgical techniques for the removal of the maxillary incisors in sciurid patients with almost total occlusion of the nasal passage. 相似文献
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Differential diagnoses,investigation, and management of a periocular swelling close to the nasolacrimal duct in a horse – A case report of Dacryops 下载免费PDF全文
Charlotte Dawson Jonathon Dixon Richard Lam Simon L. Priestnall Natalia Escanilla 《Veterinary ophthalmology》2016,19(5):427-431
To describe the differential diagnoses, investigation, and management of a periocular swelling close to the nasolacrimal duct in a horse that was consistent with a nasolacrimal duct dacryops (lacrimal cyst). A 16‐year‐old gelding, Connemara cross presented with a history of a periocular swelling rostroventral medial to the right eye that had been sampled by the referring veterinary surgeon. A cystic lesion was diagnosed following standing computed tomography. Surgical removal of the cystic lesion was performed, and the tissue was submitted for histopathologic and immunohistochemical examination. Surgical removal of the cyst was curative, and there was no recurrence of clinical signs 7 months later. There was a small amount of mineralized material in the center of the cyst. Histopathologic and immunohistochemical examination confirmed a nasolacrimal duct cyst. Dacryops can form in horses as well as other species and appears to have a favorable outcome if surgically removed. 相似文献
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Jonathon Dixon Ken Smith Justin Perkins Ceri Sherlock Tim Mair Renate Weller 《Veterinary radiology & ultrasound》2016,57(3):246-252
Melanomas are one of the most common neoplasms in the horse and are frequently found in the head region. There is a genetic predisposition in horses with a gray hair coat. Computed tomography (CT) is frequently used in referral practice to evaluate the equine head but there are few reports describing the CT appearance of melanomas in this location. The aim of this retrospective, case series study was to describe characteristics in a group of horses with confirmed disease. Case records from two referral hospitals were reviewed, and 13 horses were identified that had undergone CT of the head, with a diagnosis of melanoma based on cytology, histopathology, or visual assessment of black (melanotic) tissue. A median of 11 melanomas was identified per horse (range 3–60), with a total of 216 masses. Melanomas were found most frequently in the parotid salivary gland, guttural pouches, surrounding the larynx and pharynx and adjacent to the hyoid apparatus. In noncontrast CT images, all melanomas were hyperattenuating (median; 113.5 Hounsfield units (HU), IQR; 26 HU) compared to masseter musculature (median; 69 HU, IQR; 5.5 HU). Fifty‐six (25.9%) masses were partially mineralized and 41 (19.4%) included hypoattenuating areas. Histopathological assessment of these melanomas suggested that the hyperattenuation identified was most likely a result of abundant intracytoplasmic melanin pigment. Melanomas of the equine head appeared to have consistent CT features that aided detection of mass lesions and their distribution, although histopathological analysis or visual confirmation should still be obtained for definitive diagnosis . 相似文献
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Stephanie Stauffer Beckie Cordner Jonathon Dixon Thomas Witte 《Veterinary anaesthesia and analgesia》2017,44(4):951-958
Objective
The aim of this preliminary proof-of-concept study was to evaluate and compare the success and complication rate of infiltration of the maxillary nerve of cadaver heads using previously described surface landmarks, standard ultrasound and a novel needle guidance positioning ultrasound system (SonixGPS).Study design
Prospective, anatomical, method-comparison study.Animals
Thirty-eight equine cadaver heads.Methods
Twenty-six veterinary students performed the three methods consecutively on cadaver heads using an 18 gauge, 8.9 cm spinal needle and 0.5 mL iodinated contrast medium. Computed tomography was used to quantify success (deposition of contrast in contact with the maxillary nerve) and complication rate (contrast identified within surrounding vasculature or periorbital structures) associated with each method.Results
Perineural injection of the maxillary nerve was attempted 76 times, with an overall success rate of 65.8% (50/76) and complication rate of 53.9% (41/76). Success rates were 50% (13/26) with surface landmark, 65.4% (17/26) with standard ultrasound guidance and 83.3% (20/24) with SonixGPS guidance approaches (Fisher's exact test, p = 0.046). No significant difference in complication rate was found between the three methods.Conclusions
Ultrasound-guided maxillary nerve blocks were significantly more successful than surface landmark approaches when performed by inexperienced operators, and the highest success rate was achieved with guidance positioning system (GPS) needle guidance.Clinical relevance
Local anaesthesia of the equine maxillary nerve in the fossa pterygopalatina is frequently used for diagnostic and surgical procedures in the standing sedated horse. Due to vague superficial landmarks with various approaches and the need for experience via ultrasound guidance, this block remains challenging. GPS guidance may improve reliability of maxillary and other nerve blocks, and allow a smaller volume of local anaesthetic solution to be used, thereby improving specificity and reducing the potential for side effects. 相似文献36.
The Ca:Al status of selected Pennsylvania forest soils was assessed based on data compiled from various soil chemistry evaluations done between 1991–94. A total of 116 horizons (76 mineral, 40 organic) from 39 different soil profiles representing 18 different soil series were evaluated. Ca and Al were determined by extraction with 0.01M SrCl2. Non-linear regression analysis (logarithmic curve) showed a significant (p < 0.01) negative relationship between extractable Ca and Al across all horizons (R2 = 0.64). An acid soil infertility and aluminum stress risk assessment was conducted using the method suggested by Cronan and Grigal (1995). None of the soil organic horizons were found to be at risk; however, nearly 42% of the AE/E horizons were classified at a 50% or greater risk of producing aluminum stress to trees. The B horizons had the highest risk levels, with 91.2% classified at a 50% or greater risk level. The Ca:Al ratios of most of the mineral soil horizons included in this evaluation were low enough to present considerable risk of aluminum stress to trees growing on the sites from which these soils were collected. The application of Ca:Al ratio as a diagnostic tool in declining and nondeclining sugar maple stands in northcentral Pennsylvania generally produced consistent results for soil and roots but not for organic soil horizons and foliage of declining sugar maples. 相似文献
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Suresh Andrew Sethi Jesse R. O’Hanley Jonathon Gerken Joshua Ashline Catherine Bradley 《Landscape Ecology》2017,32(12):2327-2336
Context
Efficient restoration of longitudinal river connectivity relies on barrier mitigation prioritization tools that incorporate stream network spatial structure to maximize ecological benefits given limited resources. Typically, ecological benefits of barrier mitigation are measured using proxies such as the amount of accessible riverine habitat.Objectives
We developed an optimization approach for barrier mitigation planning which directly incorporates the ecology of managed taxa, and applied it to an urbanizing salmon-bearing watershed in Alaska.Methods
A novel river connectivity metric that exploits information on the distribution and movement of managed taxon was embedded into a barrier prioritization framework to identify optimal mitigation actions given limited restoration budgets. The value of ecological information on managed taxa was estimated by comparing costs to achieve restoration targets across alternative barrier prioritization approaches.Results
Barrier mitigation solutions informed by life history information outperformed those using only river connectivity proxies, demonstrating high value of ecological information for watershed restoration. In our study area, information on salmon ecology was typically valued at 0.8–1.2 M USD in costs savings to achieve a given benefit level relative to solutions derived only from stream network information, equating to 16–28% of the restoration budget.Conclusions
Investing in ecological studies may achieve win–win outcomes of improved understanding of aquatic ecology and greater watershed restoration efficiency.38.
Valente Jonathon J. Fischer Richard A. Ryder T. Brandt Betts Matthew G. 《Landscape Ecology》2019,34(2):373-388
Landscape Ecology - Theory predicts that movement limitation due to landscape fragmentation can reduce population viability. Understanding how landscape heterogeneity influences movement is thus... 相似文献
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Over the past 70 years, heat has been widely used as a tracer for estimating the flow of water in woody and herbaceous plants. However, most commercially available techniques for monitoring whole plant water use are invasive and the measurements are potentially flawed because of wounding of the xylem tissue. The study of photosynthate transport in the phloem remains in its infancy, and little information about phloem transport rates is available owing to the fragility of the vascular tissue. The aim of our study was to develop a compact, stand-alone non-invasive system allowing for direct detection of phloem and xylem sap movement. The proposed method uses a heat pulse as a tracer for sap flow. Heat is applied to the surface of the stem with a near-infrared laser source, and heat propagation is monitored externally by means of an infrared camera. Heat pulse velocities are determined from the thermometric data and related to the more useful quantity, mass flow rate. Simulation experiments on the xylem tissue of severed silver birch (Betula pendula Roth.) branch segments were performed to assess the feasibility of the proposed approach, highlight the characteristics of the technique and outline calibration strategies. Good agreement between imposed and measured flow rates was achieved leading to experimentation with live silver birch and oak (Quercus robur L.) saplings. It was demonstrated that water flow through xylem vessels can be monitored non-invasively on an intact stem with satisfactory accuracy despite simultaneous sugar transport in the phloem. In addition, it was demonstrated that the technique allows for unequivocal detection of phloem flow velocities. 相似文献