Biomedical subjects

James L Cook

Publications and source records attributed to James L Cook.

50 records · Page 3Linked to original sources

PubMed2002

Influence of canine recombinant somatotropin hormone on biomechanical and biochemical properties of the medial meniscus in stifles with altered stability.

OBJECTIVE: To determine biomechanical and biochemical properties of the medial meniscus in a semi-stable stifle model and in clinical patients and to determine the effect of canine recombinant somatotropin hormone (STH) on those properties. ANIMALS: 22 healthy adult dogs and 12 dogs with meniscal damage secondary to cranial cruciate ligament (CCL) rupture. PROCEDURE: The CCL was transected in 15 dogs, and stifles were immediately stabilized. Implants releasing 4 mg of STH/d were placed in 7 dogs, and 8 received sham implants. Seven dogs were used as untreated controls. Force plate analysis was performed before surgery and 2, 5, and 10 weeks after surgery. After 10 weeks, dogs were euthanatized, and menisci from surgical and contralateral stifles were harvested. The torn caudal horn of the medial meniscus in dogs with CCL rupture comprised the clinical group. Creep indentation determined aggregate modulus (HA), Poisson's ratio (v), permeability (k), and percentage recovery (%R). Water content (%W), collagen content (C), sulfated glycosaminoglycan (sGAG) content, and collagen type-I (cI) and -II (cII) immunoreactivity were also determined. RESULTS: Surgical and clinical groups had lower HA, k, %R, C, sGAG, cI, and clI and higher %W than the non-surgical group. Surgical stifles with greater weight bearing had stiffer menisci than those bearing less weight. Collagen content was higher in the surgical group receiving STH than the surgical group without STH. CONCLUSIONS AND CLINICAL RELEVANCE: Acute stabilization and moderate weight bearing of the CCLdeficient stifle appear to protect stiffness of the medial meniscus. Normal appearing menisci from CCL-deficient stifles can have alterations in biomechanical and biochemical properties, which may contribute to meniscal failure.

Animals↗

PubMedDate not supplied

The use of porcine small intestinal submucosa as a biomaterial for perineal herniorrhaphy in the dog.

OBJECTIVES: To develop an in vivo perineal hernia model, to develop a technique for using small intestinal submucosa (SIS) in perineal hernia repair, to further elucidate the biological behavior of SIS, and to compare SIS herniorrhaphy with the internal obturator muscle transposition (IOT) technique. STUDY DESIGN: Prospective evaluation comparing SIS herniorrhaphy with IOT. ANIMALS: Twelve adult castrated male, large-breed dogs. METHODS: All dogs had bilateral pelvic diaphragm defects created by complete excision of the levator ani muscle. Each dog had one side repaired using SIS and the other by IOT. Pain and inflammation were subjectively scored. Dogs were killed 2 weeks (n = 4), 12 weeks (n = 4), or 16 weeks (n = 4) after surgery. Each pelvic diaphragm was biomechanically tested to failure. The pelvic diaphragms from 2 normal dogs (n = 4 sides) were also biomechanically tested. Failure site, maximum pressure, displacement at failure, and initial linear stiffness values were determined. Histologic assessment was performed. Statistical analysis was performed with significance set at P <.05 RESULTS: No significant postoperative complications were noted. There were no significant differences in maximum pressure to failure, displacement, or stiffness when comparing normal, SIS, and IOT at any time point. The SIS group had significantly less displacement (P =.004) at 2 weeks than at weeks 12 or 16. For all herniorrhaphy techniques, the failure site was central (n = 22) or at the suture line (n = 2). At 2 weeks, histologic evaluation of tissues from the IOT group showed inflammation, mineralization, and necrosis, which were not present in tissues from the SIS group. Histologic examination at 12 and 16 weeks showed no microscopic differences in cell population or tissue characteristics between the IOT and SIS groups. CONCLUSIONS: SIS herniorrhaphy was successfully performed in this in vivo model of perineal hernia in the dog. CLINICAL RELEVANCE: This study suggests that SIS can be used as a primary means of repair, as augmentation when the internal obturator muscle is thin and friable, or as a salvage procedure in cases of recurrence in dogs with perineal hernia.

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PubMedDate not supplied

Effects of degree of acetabular rotation after triple pelvic osteotomy on the position of the femoral head in relationship to the acetabulum.

OBJECTIVE: To assess the effect of rotating the acetabulum 20 degrees and 30 degrees on percent coverage (PC) of the femoral head by the acetabulum and Norberg angle (NA) after triple pelvic osteotomy (TPO). STUDY DESIGN: Retrospective study. ANIMAL POPULATION: Fifty-six client-owned dogs. METHODS: PC and NA were measured from preoperative, immediate postoperative, first recheck, and second recheck radiographs to compare the effects of 20 degrees and 30 degrees of rotation of the acetabulum after TPO for treatment of hip dysplasia. RESULTS: Within the 20 degrees rotation group, PC and NA values were significantly greater at each subsequent evaluation time starting at the preoperative measurement except for NA between the first and second recheck times. Within the 30 degrees rotation group, PC and NA values were significantly greater at each subsequent evaluation time starting at the preoperative measurement except for PC and NA between the first and second recheck times. No significant differences between the 20 degrees and 30 degrees rotation groups were found at any corresponding times for either PC or NA. CONCLUSIONS: Acetabular rotation of 20 degrees provided the same degree of improvement in acetabular femoral head coverage as 30 degrees of rotation after TPO at the immediate postoperative, first recheck, and second recheck evaluation times. CLINICAL RELEVANCE: Based on PC and NA, 20 degrees rotation of the acetabulum provides as much benefit as 30 degrees of acetabular rotation when performing a TPO.

Acetabulum↗

PubMedDate not supplied

Fibrochondrogenesis of free intraarticular small intestinal submucosa scaffolds.

Naturally occurring biomaterials, such as small intestine submucosa (SIS), are attractive as potential scaffolds for engineering various tissue types. The aim of this study was to determine whether acellular SIS scaffolds can support cell attachment and ingrowth in a diarthroadial joint without significant intraarticular hemorrhage. Disks of porcine SIS were arthoscopically implanted freely within a randomized knee joint of 21 dogs and harvested 1, 2, 3, and 6 weeks postoperatively. Harvested disks were assessed for gross and histologic appearance, cellular infiltration, and immunoreactivity of collagenase and collagen types I and II. Knee synovium and synovial fluid were also evaluated. All disks were thickened and opacified at harvest. Eleven disks (52%) had adhered to intraarticular tissues and cellular infiltration into the disks was positively correlated with tissue adherence. Further, tissue adherence was positively correlated with duration of intraarticular implantation. Five disks (24%) contained focal areas of homogeneous extracellular matrix. A trend toward more collagenase immunoreactivity was noted in the 3-week disks. Collagen type I was present in remaining SIS and extracellular matrix associated with infiltrated cells. Placed freely within a joint, acellular SIS disks underwent cellular and extracellular matrix modification resulting in fibrocartilage-like tissue. Utilization of SIS as a scaffold for intraarticular tissue-engineering applications is supported as cytoconductivity, appropriate residence time, and absence of untoward effects of implantation are desirable criteria for a tissue-engineering biomaterial.

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PubMedDate not supplied

Arthroscopic verification of ultrasonographic diagnosis of meniscal pathology in dogs.

OBJECTIVE: To determine the clinical usefulness of ultrasonography for diagnosis of meniscal pathology in dogs. STUDY DESIGN: Double-blind prospective study. ANIMALS: Dogs (n=10) with lameness localized to the stifle. MATERIALS AND METHODS: Sonographic examination of each affected stifle was performed by 1 ultrasonographer unaware of specific historical and clinical data for the dog. Sonographic findings were recorded, but not reviewed until study completion. Arthroscopic examination of the affected stifle was performed within 48 hours of ultrasonography by 1 surgeon unaware of ultrasonographic findings. Arthroscopic findings were recorded, but not reviewed until study completion. Two investigators compared the ultrasonographic and arthroscopic findings at study completion to determine the sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: Two of the 10 dogs had bilateral stifle evaluation. Twenty-four lateral and medial menisci, with normal and abnormal findings, were examined. The sensitivity and specificity for ultrasonographic diagnosis were 90.0% and 92.9%, respectively; positive and negative predictive values were 90.0% and 92.9%, respectively. CONCLUSIONS: Ultrasonography is highly specific and sensitive for diagnosing bucket handle tears of the medial meniscus in dogs. CLINICAL RELEVANCE: Ultrasonographic evaluation of menisci in dogs is a noninvasive method for accurately and efficiently diagnosing pathology, determining the need for surgical intervention, and providing comprehensive information to clients.

Animals↗

PubMedDate not supplied

Short-term aseptic loosening of the femoral component in canine total hip replacement: effects of cementing technique on cement mantle grade.

OBJECTIVES: To evaluate the effects of different cementing techniques on radiographic cement mantle grade and short-term aseptic loosening of the femoral component in canine total hip replacement (THR). STUDY DESIGN: Retrospective study. SAMPLE POPULATION: Radiographs of 284 dogs that had THR. METHODS: Immediate postoperative radiographs of 284 dogs that had cemented THR were reviewed by 4 surgeons and 1 radiologist and assigned a cement mantle grade using a 4-grade classification system. Dog age and weight at surgery, cementing technique (1st, 2nd, 3rd generation), complications (type and timing), and follow-up time were retrieved and analyzed. RESULTS: Mean cement mantle score for 2nd generation technique was significantly higher than 3rd generation technique and both were significantly higher than 1st generation technique (P<.001). Aseptic loosening was the 2nd most common complication observed with an incidence of 2.1%. Mean time from surgery to last follow-up examination was 122 days. No statistically significant difference in incidence of aseptic loosening was identified among different cement mantle grades or cementing techniques. CONCLUSIONS: Advanced cementing techniques resulted in better cement mantles based on grading of immediate postoperative radiographs, however grading did not predict short-term aseptic loosening. Cementing technique seemingly did not affect the incidence of short-term aseptic loosening of the femoral component for dogs in this study. CLINICAL RELEVANCE: Our study suggests that advances in cementing technique may result in improvements in the radiographic grade of cement mantles. With respect to aseptic loosening of the femoral component, our data only suggest that short-term (3 months-3 years) loosening cannot be predicted by immediate postoperative radiographic evaluation of cement mantle.

Animals↗

PubMedDate not supplied

Measurement of angles of abduction for diagnosis of shoulder instability in dogs using goniometry and digital image analysis.

OBJECTIVE: To compare abduction angles of shoulders with medial instability and unaffected shoulders in the same dogs and in age- and breed-matched dogs. STUDY DESIGN: Case-control study. ANIMALS: Dogs with medial instability of the shoulder (n=33) and 26 control dogs. METHODS: Dogs were sedated and positioned in lateral recumbency with both scapulas parallel to the table. With the elbow and shoulder in extension, the non-recumbent limb was maximally abducted and the angle between the scapular spine and lateral aspect of the brachium measured with a goniometer; a digital image was taken from the cranial aspect. Both techniques were performed in triplicate by 2 examiners. Mean abduction angles for each shoulder were determined from goniometric measurements and image analysis. Data were analyzed for significant differences between affected and unaffected shoulders, measurement techniques, and examiners. Strength of correlation between measurement techniques was determined. RESULTS: Mean abduction angles for shoulders with instability (53.7+/-4.7 degrees goniometric, 51.2+/-4.9 degrees image) were significantly (P<.001) larger than for all unaffected shoulders (32.6+/-2.0 degrees goniometric, 30.9+/-2.3 degrees image). In dogs diagnosed with instability, affected shoulders had significantly (P<.001) larger abduction angles than the contralateral (unaffected) shoulders. No significant differences were identified between right and left shoulders for control dogs, measurement techniques, or examiners. A strong (r=0.90) significant (P<.001) positive correlation between measurement techniques was noted. CONCLUSIONS: Shoulder abduction angles measured under sedation provide objective data for diagnosis of shoulder instability in dogs. Shoulders with clinical and arthroscopic evidence of medial instability have significantly higher abduction angles than shoulders that are considered normal. CLINICAL RELEVANCE: Determination of shoulder abduction angles should be included in the diagnostic protocol for forelimb lameness assessment in dogs.

Animals↗

PubMedDate not supplied

Treatment of dogs diagnosed with medial shoulder instability using radiofrequency-induced thermal capsulorrhaphy.

OBJECTIVE: To report clinical findings and outcome in dogs diagnosed with medial shoulder instability (MSI) treated with radiofrequency-induced thermal capsulorrhaphy (RITC). STUDY DESIGN: Retrospective study. ANIMALS: Dogs (n=43) with MSI. METHODS: Medical records from consecutive cases with MSI based on orthopedic examination, palpation of shoulder abduction angles, and arthroscopic findings were used to determine clinical findings and long-term (> or = 1 year) outcome of RITC. RESULTS: Forty-three dogs met the criteria for inclusion; 2 dogs had bilateral MSI. The most common clinical findings were chronic unilateral weight-bearing lameness, large (> 45 degrees) shoulder abduction angles, and spinatus muscle atrophy in the affected limb. Mean preoperative abduction angle (50.7 degrees +/- 4.8 degrees) in affected shoulders was significantly larger than in the unaffected shoulders (32.5 degrees +/- 2.1 degrees). Mean postoperative abduction angle in affected shoulders was not significantly different from unaffected shoulders when measured immediately, 8, 16-20 weeks, and approximately 1 year after surgery. Follow-up evaluation ranged from 1 to 6.2 years. RITC treatment resulted in improved clinical function in 40 cases (93%) with 34 cases (79%) considered excellent; 3 cases (7%) were considered failures. CONCLUSIONS: RITC was a safe and effective method of treatment of MSI in most dogs studied. CLINICAL RELEVANCE: RITC can be considered as a viable option for surgical treatment of selected cases of MSI in dogs.

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PubMedDate not supplied

Measurement of articular cartilage stiffness of the femoropatellar, tarsocrural, and metatarsophalangeal joints in horses and comparison with biochemical data.

OBJECTIVE: To determine normal cartilage stiffness values in different weight-bearing and non-weight-bearing areas of 3 different equine joints, and to evaluate the relationship between cartilage stiffness and glycosaminoglycan (GAG) and collagen content. STUDY DESIGN: Compressive stiffness of the articular cartilage was measured in 8 horse cadaver femoropatellar (FP), tarsocrural (TC), and metatarsophalangeal (MT) joints. Gross evaluation, collagen content, GAG content, and histologic appearance were assessed for each measurement location. ANIMALS: Eight equine cadavers (4 intact females, 4 castrated males; 7 Quarter Horse or Quarter Horse type, 1 Arabian; aged 4-12 years, weighing 400-550 kg). METHODS: The articular surfaces of 8 equine cadaver FP, TC, and MT joints were grossly evaluated for signs of articular cartilage pathology. Stiffness at preselected sites (FP joint-6 sites; TC joint-3 sites; MT joint-4 sites) was determined using an arthroscopic indentation instrument. Biochemical composition (collagen, GAG content) and histologic evaluation (modified Mankin score) were assessed for each measurement site. RESULTS: All cartilage from all sites evaluated was determined to be normal based on macroscopic and histologic assessments. No significant correlation between Mankin scores and cartilage stiffness values was observed. Site differences in cartilage stiffness were measured in all 3 joints (P<.001). GAG or collagen content had a significant positive correlation with stiffness values in 6 of 13 sites (P<.05, r>0.622, r2>0.387). CONCLUSION: Relative cartilage stiffness values measured in healthy equine joints are site dependent and can be measured using an indentation device intended for arthroscopic application. CLINICAL RELEVANCE: An indentation instrument provided an objective means of determining relative compressive stiffness of articular cartilage. Further research needs to be performed to confirm the site and joint differences observed in this study in clinically normal horses and to determine if the tester can be used clinically to predict articular cartilage pathology.

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PubMedDate not supplied

In vitro evaluation of screws and suture anchors in metaphyseal bone of the canine tibia.

OBJECTIVE: To compare ease of insertion, load to failure, and mode of failure of cortical and cancellous screws, BoneBiter, IMEX, and TwinFix suture anchors in canine metaphyseal tibial bone. STUDY DESIGN: Experimental biomechanical study. ANIMALS: Canine cadaveric tibias. METHODS: One investigator inserted all anchors and subjectively evaluated ease of placement. Anchor systems were loaded to failure along axis of insertion with audio-video recording to determine failure mode. RESULTS: BoneBiter was the most difficult anchor to insert successfully. Mean+/-SD loads to failure were cancellous screw (711+/-193 N), IMEX 4.7 mm 18 g wire (661+/-163 N), IMEX 4.0 mm 18 g wire (661+/-165 N), cortical screw (635+/-184 N), BoneBiter #5 Kevlar suture (393+/- 109 N), and TwinFix 5.0 mm #2 polyester (267+/-73 N). No significant differences were noted among the cortical screw, cancellous screw, IMEX 4.7 and 4.0 mm, all of which were significantly (P<.001) greater than BoneBiter and TwinFix . Failure modes were pullout of bone, suture-wire breakage, eyelet breakage, or no failure to 1000 N: screws (18,0,0,2), IMEX (18,1,1,0), BoneBiter (2,8,0,0), and TwinFix (0,10,0,0). CONCLUSIONS: Fixation devices were user friendly, with the exception of BoneBiter. Mode of failure is dependent on suture material and anchor design. Cortical and cancellous screws, and IMEX anchors with 18 g wire have significantly greater load to failure compared with BoneBiter and TwinFix suture anchors. CLINICAL RELEVANCE: Based on load to failure, ease of use, design characteristics, and cost, IMEX anchors may have advantages over other comparable soft tissue fixation devices.

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Canine synovial sarcoma: a retrospective assessment of described prognostic criteria in 16 cases (1994-1999).

Pertinent patient data and biopsied tissue from 16 cases of canine synovial sarcoma (SS) were reviewed. Histopathological grade, clinical stage, and tissue immunoreactivity to cytokeratin (broad stain, AE1/AE3 and cytokeratin 7) and vimentin were determined and correlated with survival. Effect of treatment on survival was similarly evaluated. Neither clinical stage nor histopathological grade significantly affected survival patterns. Tissues from all cases stained >30% positively with vimentin, whereas no tissue from any case exhibited cytokeratin immunoreactivity. Dogs receiving surgical tumor excision or amputation had a significantly higher survivability than those receiving no treatment (P<0.02). Treatment aggressiveness may be more appropriate than clinical staging or tumor grading in predicting survival. Reliability of diagnosing and prognosticating canine SS with current immunohistochemistry protocols should be questioned.

Amputation, Surgical↗

PubMedDate not supplied

Distraction osteogenesis for treatment of premature physeal closure and shortening of the third and fourth metatarsals of a dog.

A 4-month-old Siberian husky was presented for a history of lameness of the left hind limb. Physical and radiographic examination revealed a 1-cm shortening of metatarsals III and IV, with subsequent hyperextension of the digits on the left hind paw. A circular external skeletal fixator was used to accomplish distraction osteogenesis in both metatarsals over a period of 15 days. Treatment was successful in restoring appropriate length of the metatarsals and in resolution of the lameness. At 6 and 12 months after surgery, the owner reported that the dog was ambulating normally and had no complications related to the surgery.

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Arthroscopic biceps tenodesis: technique and results in six dogs.

Biceps tenodesis was performed using an arthroscopic-assisted technique on six dogs diagnosed with chronic bicipital tendon pathology. The technique was performed using two different fixation methods (i.e., cannulated interference screw, cannulated screw and tissue washer). All six dogs had successful outcomes in terms of return to full function at a mean follow-up time of 11.7 months after surgery. Arthroscopic biceps tenodesis is a feasible option for surgical management of biceps tendon pathology, and it may have advantages over open tenodesis and open or arthroscopic tenotomy. Further study is needed before definitive recommendations regarding indications, complications, and prognosis associated with arthroscopic biceps tenodesis can be made.

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Nonsteroidal antiinflammatory drugs: a review.

The increasing use of nonsteroidal antiinflammatory drugs (NSAIDs) in small animals has resulted in the development of new and innovative additions to this class of drugs. Examples of NSAIDs now available for use in small animals include aspirin, etodolac, carprofen, ketoprofen, meloxicam, deracoxib, and tepoxalin. The purposes of this article are to review the pathophysiology of prostaglandin synthesis and inhibition, the mechanisms of action, pharmacokinetics, pharmacological effects, and potential adverse reactions of aspirin and the newly released NSAIDs.

Animal Diseases↗