A Prosthetic Implant for the Equine Carpal Joint: Surgical Technique and Results

A prosthesis designed to partially replace the articular surfaces of the radial and third carpal bones was implanted bilaterally in 6 normal horses. The prosthesis consisted of a convex metal alloy component, and a concave ultra-high molecular weight polyethylene component, for implantation into the radial and third carpal bones, respectively. One horse underwent the soft tissue approach only to serve as a control. Effects on joint motion and pathologic changes were monitored over a 6-month period using clinical examination, synovial fluid analysis, electrogoniometry, high-speed cinematography, radiography, and gross and microscopic pathologic examination. Six months following implantation, all horses that received implants would trot, with slight to moderate lameness. Electrogoniometric and cinematographic evaluation of joint motion demonstrated a reduction in amplitude of the carpus in 4 horses receiving implants; however, in 2 horses, the reduction was less than, or equivalent to, that of the control horse. One horse that received the prosthesis was rideable, and was able to run with minimal lameness. Radiography, synovial fluid analysis, and gross and microscopic pathologic examination revealed varying degrees of synovitis and osteoarthritis. Biomechanical alterations of the middle carpal joint and release of wear particles from the prosthesis were considered to be major causes of these secondary changes. Changes in design of the prosthesis, intended to more accurately maintain normal joint biomechanics are proposed.     

Results of Transsphenoidal Hypophysectomy in 52 Dogs With Pituitary-Dependent Hyperadrenocorticism

Objective —To evaluate microsurgical transsphenoidal hypophysectomy in dogs with pituitary-dependent hyperadrenocorticism (PDH). Study Design —Prospective study to evaluate the results (survival and disease-free interval, remission, recurrence) and complications of microsurgical transsphenoidal hypophysectomy by clinical follow-up, computed tomography (CT), and urinary corticoid-to-creatinine (C/C) ratios in dogs with PDH. The effect of surgical experience was investigated by comparing results of hypophysectomy cases 1 through 26 and 27 through 52. Animals or Sample Population—52 dogs with PDH. Results —Preoperative CT enabled accurate assessment of pituitary size (24 nonenlarged and 28 enlarged) and localization relative to intraoperative anatomic landmarks. Treatment failures included procedure-related mortalities (five dogs) and incomplete hypophysectomies (four dogs). The 1-year estimated survival rate was 84% (95% confidence interval [CI], 71% to 92%). The 2-year estimated survival rate was 80% (95% CI, 65% to 90%). In 43 dogs, the hyperadrenocorticism went into remission. Hyperadrenocorticism recurred in five dogs. The 1-year estimated relapse-free fraction was 92% (95% CI, 76% to 97%). The main complications were transient, mild, postoperative hypernatremia; transient reduction or cessation of tear production (25 eyes in 18 dogs); permanent (five dogs) or prolonged (nine dogs) diabetes insipidus; and secondary hypothyroidism. Normal tear production had resumed in all but one case after a median period of 10 weeks. In the second case series (27 through 52), the hospitalization period was shorter, the number of dry eyes fewer, the survival fraction greater, and the postoperative mortality lower than in the first series. In 15 dogs in which remission was obtained, postoperative CT images suggested the presence of small pituitary remnants; in 1 of these, hyperadrenocorticism recurred. In 46 dogs, the histological diagnosis was pituitary adenoma. Conclusions —Microsurgical transsphenoidal hypophysectomy in dogs with PDH is an effective method of treatment in specialized veterinary institutions having access to advanced pituitary imaging techniques. Postoperative CT findings do not correlate well with remission or subsequent recurrence of hyperadrenocorticism. Clinical Relevance —The neurosurgeon performing hypophysectomies must master a learning curve and must be familiar with the most frequent complications of the operation to recognize them as early as possible and to treat them immediately and effectively. Urinary C/C ratios are sensitive indicators for the assessment of remission and recurrence of hyperadrenocorticism.     

东北地区和黄淮海地区玉米种质利用模式的比较

利用SSR标记分别对东北春播和黄淮海夏播玉米产区主要自交系的遗传多样性进行分析,并在此基础上对东北和黄淮海地区的玉米种质利用模式进行比较。东北地区利用的种质类型比较丰富,包括PA、PB、旅大红骨、Lan.和塘四平头亚群,利用的杂种优势模式以PA×旅大红骨为主,在生育期较短的玉米产区Lan.×塘四平头是很重要的利用模式,在黑龙江省和吉林省北部地方种质发挥了重要作用。黄淮海夏播玉米产区利用的种质主要是PA、PB和塘四平头亚群,利用的杂种优势模式以PA×塘四平头为主。PA×PB杂种优势模式呈现上升趋势,有利于实现跨区域整合玉米种质的杂种优势群和模式。     

European Regional Convergence Revisited: A Weighted Least Squares Approach

A plethora of past studies have concluded that unconditional β‐convergence is present in a broad sample of regions, implying that poor regions grow faster than rich ones. All these econometric studies tend to overlook the relative importance or size of each region in the national setting, treating all regional observations as equal. However, this assumption might lead to unrealistic or misleading results. Convergence analysis could be more meaningful if it included a weighting mechanism taking into account the size of regions. The aim of this paper is to investigate whether the inclusion of a weighting mechanism in β‐convergence analysis, giving more weight to larger regions and less to smaller ones, can result in sharply different implications for the regional convergence‐divergence process. For this reason, both unweighted ordinary least squares (OLS) and weighted least squares estimators are used in the analysis of regional (intra‐national) convergence within 10 European Union (EU) countries over the period 1990–2000. The comparison between the two methods reveals that when regions are appropriately weighted for their size, intra‐national divergence, rather than convergence found with the OLS approach, seems to be the dominant experience in the EU.     

美国甘薯育种材料遗传多样性的ISSR分析

对25份美国甘薯[Ipomoea batatas (L.) Lam.]品系及另外作为对照的47份甘薯种质资源进行ISSR分析,利用NTSYS软件分析遗传相似系数,采用UPGMA方法进行聚类,构建亲缘关系系统图.结果显示:10个引物共扩增出78个条带,其中有73条呈现多态性,多态位点比例高达93.6%;25份美国甘薯育种材料与对照种质资源的平均遗传相似性系数是0.74.表明美国甘薯育种材料遗传多样性较高,可将其中的6-3-1、6-8-7等品系应用于国内甘薯育种中,以扩大遗传背景.     

Electron microscopy and autoradiography

The combined techniques of electron microscopy and autoradiography were used for the purpose of differentiating radioactive from nonradioactive particles collected on membrane filters. Newer methods of processing the membrane filters and applying the nuclear emulsion have resulted in an improvement in the qualitative nature of the procedure.     

A Muscle Separating Approach to the Equine Shoulder Joint for the Treatment of Osteochondritis Dissecans

A muscle separating approach with tenotomy of the teres minor was used to expose osteochondritis dissecans lesions in the shoulder joints of five horses. Horses selected for surgery were severely lame or had a long history of lameness. Adequate surgical access allowed removal of cartilage flaps, curettage of the subchondral bone, and in one horse, the removal of an osteocartilaginous free body. Surgical wounds healed by primary intention; one horse developed a seroma that was drained. Three of the five horses were clinically sound 3 months following surgery. Two other horses were pasture sound but lame after extensive athletic activity.     

Transsphenoidal Hypophysectomy in Beagle Dogs: Evaluation of a Microsurgical Technique

Objective — Assessment of a microsurgical technique for transsphenoidal hypophysectomy in dogs.
Study Design — Prospective study using physical examination, pituitary function testing, computed tomography (CT), and histological examination at autopsy.
Animals or Sample Population — Eight laboratory beagle dogs.
Methods — Pituitary function was assessed before and at 10 weeks after hypophysectomy by combined administration of four releasing hormones (anterior pituitary), administration of haloperidol (pars intermedia), and infusion of hypertonic saline (posterior pituitary).
Results — CT imaging enabled accurate preoperative localization of the pituitary. Appropriate positioning and surgical technique facilitated exposure of the pituitary and its extraction without hemorrhage. Postoperative recovery was generally uncomplicated. None of die eight dogs had somatotropic, gonadotropic, lactotropic, melanotropic, or posterior pituitary responses to stimulation at 10 weeks after hypophysectomy. Four dogs (ACTH nonresponders) also had no cortico-tropic response and four (ACTH responders) had small but significant responses in the combined anterior pituitary function test. Adrenocortical atrophy was more pronounced in the ACTH nonresponders man in the responders. No residual pituitary tissue was found along the ventral hypothalamic diencephalon but nests of pituitary cells were found embedded in fibrous tissue in the sella turcica.
Conclusions — The surgical technique proved to be safe and effective. Microscopic nests of pituitary cells in the sella turcica may be responsible for residual corticotropic response to hypophysiotropic stimulation after hypophysectomy.
Clinical Relevance — The surgical technique may be used in the treatment of dogs with pituitary-dependent hyperadrenocorticism. The corticotropic response is the most sensitive criterion in assessing completeness of hypophysectomy in dogs.