The location of sites and effect of semiconductor diode trans-scleral cyclophotocoagulation on the buphthalmic equine globe.

PURPOSE: To determine appropriate location and energy settings for trans-scleral cyclophotocoagulation (TSCPC) for buphthalmic equine globes. ANIMALS: Eleven horses with a buphthalmic eye blinded by glaucoma presented for enucleation. METHODS: Globe and corneal dimensions were measured via ultrasonography and calipers, and TSCPC was performed under general anesthesia immediately prior to enucleation. Part 1: In nine globes, sixty sites were lasered 4 mm posterior to the limbus in the dorsotemporal and ventrotemporal quadrants at settings of 1500 milliwatts and 1500 ms. Globes were processed and sectioned sagitally over the temporal aspect in two blocks, each with five histologic sections examined by light microscopy. A digital imaging system was used to determine the location and length of the pars plicata on one slide from each block. Part 2: Based on results in Part 1, two globes were measured and lasered using the same time and energy settings at the following distances posterior to the limbus: 8 mm dorsally, 6 mm dorsotemporally, 5 mm ventrotemporally, and 5 mm ventrally. RESULTS: Globe and corneal dimensions exceeded normal values in all globes. Part 1: In all nine globes, photocoagulation affected the anterior ciliary processes and iris base and in 8/9 coagulation of the pectinate ligaments was noted. Part 2: In both globes, coagulation was confined to the pars plicata. CONCLUSIONS: The previously recommended TSCPC sites are located too far anteriorly for a buphthalmic globe. Buphthalmic equine globes should have TSCPC performed at the following distances posterior to the limbus: 6-8 mm dorsally, 5-6 mm dorsotemporally, 4-5 mm ventrotemporally, and 4-5 mm ventrally.

Accuracy of computed tomography in determining lesion size in canine appendicular osteosarcoma.

Multidetector contrast enhanced computed tomography with acquisition of 0.625-mm thick transverse images was used to measure the extent of appendicular osteosarcoma in 10 dogs. The measured length of tumor based on CT was compared to the true length of tumor using histopathology. There was a statistically significant association with good correlation between the true length of osteosarcoma compared to the length of intramedullary/endosteal abnormalities on CT with a mean overestimation of 1.8% (SD = 15%). There was not a statistically significant association between the true tumor length and the length of periosteal proliferation on CT with a mean overestimation of 9.7% (SD = 30.3%). There was a statistically significant association, but with poor correlation, between the true tumor length compared to the length of abnormal contrast enhancement with a mean overestimation of 9.6% (SD = 34.8%). The extent of intramedullary/endosteal CT abnormalities assessed from submillimeter transverse images may be of value in assessing patient candidacy and surgical margins for limb-sparing surgery.

Fractures in regions of adaptive modeling and remodeling of central tarsal bones in racing Greyhounds.

OBJECTIVE: To evaluate and compare bone modeling and remodeling in fractured and non-fractured central tarsal bones (CTBs) of racing Greyhounds. SAMPLE: Paired cadaveric tarsi from 6 euthanized racing Greyhounds with right CTB fractures and 6 racing Greyhounds with other nontarsal injuries. PROCEDURES: CTBs were dissected and fractured CTBs were reconstructed. Central tarsal bones were evaluated through standard and nonscreen high-detail radiography, computed tomography, and histologic examination. The bone mineral density (BMD) was calculated adjacent to fracture planes and as a gradient on sagittal computed tomographic images. Sagittal and transverse plane sections of bone were obtained and submitted for subjective histologic assessment. Linear mixed-effects models were used to compare findings. RESULTS: Fractured right CTBs had greater BMD in the dorsal and midbody regions of the sagittal plane sections than did nonfractured CTBs. The BMD ratios from bone adjacent to the dorsal slab fracture planes were not different between fractured and nonfractured right CTBs. CONCLUSIONS AND CLINICAL RELEVANCE: Findings supported the existence of site-specific bone adaptation in CTBs of Greyhounds, with modeling and remodeling patterns that were unique to fractured right CTBs. The dorsal and midbody regions of fractured bones had greater BMD, and fractures occurred through these zones of increased BMD.

The long-term effects of semiconductor diode laser transscleral cyclophotocoagulation on the normal equine eye and intraocular pressure(a).

OBJECTIVE: To describe the long-term histologic and intraocular pressure (IOP) lowering effects of diode laser transscleral cyclophotocoagulation (TSCP) on the normal equine eye. ANIMALS: Eight normal adult horses. PROCEDURES: TSCP was performed in one randomly assigned eye. Sixty spots were treated at settings of 1500 ms and 1500 mW. Two horses were randomly selected for euthanasia at 2, 4, 12, or 24 weeks post-TSCP. Both eyes were enucleated and histologically evaluated. Intraocular pressure was measured by applanation tonometry prior to TSCP, immediately post-TSCP, twice daily for 7 days post-TSCP and then monthly until study conclusion. A longitudinal model estimated the average IOP values for the treated and untreated eyes at 1 week, 1, 3, and 6 months post-TSCP. RESULTS: All treated eyes at all time periods exhibited four characteristic histologic lesions: scleral collagen hyalinization, ciliary body pigment dispersion and clumping, focal disruption of the ciliary body epithelium, and focal ciliary process atrophy. After TSCP, there were no significant changes in IOP from baseline for the control eyes, while the IOP in treated eyes was significantly decreased from baseline (P < 0.05) at all time periods. The estimated decrease in IOP in the treated eyes compared to baseline IOP at 6 months was -3.76 mmHg for an average decrease in IOP of 20% from baseline. CONCLUSION: Diode laser TSCP produces histologic lesions in the equine ciliary body that result in a significant and sustained decrease in IOP. TSCP may be an effective management for equine glaucoma.

Dermal fibroblast-mediated BMP2 therapy to accelerate bone healing in an equine osteotomy model.

This study evaluated healing of equine metacarpal/metatarsal osteotomies in response to percutaneous injection of autologous dermal fibroblasts (DFbs) genetically engineered to secrete bone morphogenetic protein-2 (BMP2) or demonstrate green fluorescent protein (GFP) gene expression administered 14 days after surgery. Radiographic assessment of bone formation indicated greater and earlier healing of bone defects treated with DFb with BMP2 gene augmentation. Quantitative computed tomography and biomechanical testing revealed greater mineralized callus and torsional strength of DFb-BMP2-treated bone defects. On the histologic evaluation, the bone defects with DFb-BMP2 implantation had greater formation of mature cartilage and bone nodules within the osteotomy gap and greater mineralization activity on osteotomy edges. Autologous DFbs were successfully isolated in high numbers by a skin biopsy, rapidly expanded without fastidious culture techniques, permissive to adenoviral vectors, and efficient at in vitro BMP2 protein production and BMP2-induced osteogenic differentiation. This study demonstrated an efficacy and feasibility of DFb-mediated BMP2 therapy to accelerate the healing of osteotomies. Skin cell-mediated BMP2 therapy may be considered as a potential treatment for various types of fractures and bone defects.

Effects of orthopedic implants with a polycaprolactone polymer coating containing bone morphogenetic protein-2 on osseointegration in bones of sheep.

OBJECTIVE: To determine elution characteristics of bone morphogenetic protein (BMP)-2 from a polycaprolactone coating applied to orthopedic implants and determine effects of this coating on osseointegration. ANIMALS: 6 sheep. PROCEDURES: An in vitro study was conducted to determine BMP-2 elution from polycaprolactone-coated implants. An in vivo study was conducted to determine the effects on osseointegration when the polycaprolactone with BMP-2 coating was applied to bone screws. Osseointegration was assessed via radiography, measurement of peak removal torque and bone mineral density, and histomorphometric analysis. Physiologic response was assessed by measuring serum bone-specific alkaline phosphatase activity and uptake of bone markers. RESULTS: Mean +/- SD elution on day 1 of the in vitro study was 263 +/- 152 pg/d, which then maintained a plateau at 59.8 +/- 29.1 pg/d. Mean peak removal torque for screws coated with polycalprolactone and BMP-2 (0.91 +/- 0.65 dN x m) and screws coated with polycaprolactone alone (0.97 +/- 1.30 dN.m) did not differ significantly from that for the control screws (2.34 +/- 1.62 dN x m). Mean bone mineral densities were 0.535 +/- 0.060 g/cm(2), 0.596 +/- 0.093 g/cm(2), and 0.524 +/- 0.142 g/cm(2) for the polycaprolactone-BMP-2-coated, polycaprolactone-coated, and control screws, respectively, and did not differ significantly among groups. Histologically, bone was in closer apposition to the implant with the control screws than with either of the coated screws. CONCLUSIONS AND CLINICAL RELEVANCE: BMP-2 within the polycaprolactone coating did not stimulate osteogenesis. The polycaprolactone coating appeared to cause a barrier effect that prevented formation of new bone. A longer period or use of another carrier polymer may result in increased osseointegration.

Influence of bone cements on bone-screw interfaces in the third metacarpal and third metatarsal bones of horses.

OBJECTIVE: To compare biomechanical strength, interface quality, and effects of bone healing in bone-implant interfaces that were untreated or treated with calcium phosphate cement (Ca-cement), magnesium phosphate cement (Mg-cement), or polymethylmethacrylate (PMMA) in horses. ANIMALS: 6 adult horses. PROCEDURES: 4 screw holes were created (day 0) in each third metacarpal and third metatarsal bone of 6 horses. In each bone, a unicortical screw was placed in each hole following application of Ca-cement, Mg-cement, PMMA, or no treatment (24 screw holes/treatment). Screws were inserted to 2.82 N m torque. Horses were euthanized and bones were harvested at day 5 (16 screw holes/treatment) or day 182 (8 screw holes/treatment). Radiography, biomechanical testing, histomorphometry, and micro-computed tomography were performed to characterize the bone-implant interfaces. RESULTS: Use of Mg-cement increased the peak torque to failure at bone-implant interfaces, compared with the effects of no treatment and Ca-cement, and increased interface toughness, compared with the effects of no treatment, Ca-cement, and PMMA. Histologically, there was 44% less Ca-cement and 69% less Mg-cement at the interfaces at day 182, compared with amounts present at day 5. Within screw threads, Ca-cement increased mineral density, compared with PMMA or no treatment. In the bone adjacent to the screw, Mg-cement increased mineral density, compared with PMMA or no treatment. One untreated and 1 Ca-cement-treated screw backed out after day 5. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, Mg-cement promoted bone-implant bonding and adjacent bone osteogenesis, which may reduce the risk of screw loosening.

Extra-adrenal paraganglioma of the equine orbit: six cases.

At The Ohio State University from 1994-2006 six of seven horses evaluated for primary orbital disease were diagnosed with extra-adrenal paraganglioma (EAPG). The horses ranged in age from 14 to 24 years, with a mean of 16.8 years. Duration of clinical signs was 1.5 years to 5 years, with a mean of 2.8 years. Clinical signs varied, but all six had non-painful exophthalmus of the right eye. Five horses had complete ocular exams reported; three of five had decreased to absent vision, two of five had pale optic nerves, and in three of five, difficulty of retropulsion of the globe was noted. Diagnostic tests performed included complete blood count, serum profile, radiography, ultrasound, computed tomography, true-cut biopsy, ocular examination, guttural pouch endoscopy, oral examination, and physical examination. Expulsive hemorrhage during orbital exenteration occurred in all horses. In five of six cases, tumor extension through the orbital foramen was apparent intra-operatively. Histopathologic appearance of all surgically removed tissues consisted of sheets of polygonal cells with abundant lightly granular cytoplasm, round nuclei with vesicular chromatin, and rare mitoses. Neoplastic cells were arranged into small groups separated by a fine fibrovascular stroma. All six cases were chromagranin positive on immunohistochemical staining. Follow-up ranged from six months to six years, with a mean of two years. Four of the five horses that recovered from surgery had no apparent tumor recurrence in 6-48 months.

Magnetic resonance imaging of the initial active stage of equine laminitis at 4.7 T.

Equine laminitis is a severely debilitating disease. There is a poor understanding of the underlying pathophysiology, and traditional imaging modalities have limited diagnostic capacity. High field strength magnetic resonance (MR) imaging allows direct visualization of the laminae, which other modalities do not. This would prove useful both in assessment of clinical patients and in further investigation into the pathophysiology of the disease. The objective of this study was to characterize the anatomic changes within the equine foot associated with the initial active stage of laminitis. Images obtained using a 4.7 T magnet were compared with digital radiographs using histologic diagnosis as the reference standard. Objective measurements and subjective evaluation for both modalities were evaluated for the ability to predict the histologic diagnosis in horses with clinical signs of laminitis as well as in clinically normal horses and horses that were in a population at risk for developing laminitis. Signal intensity and architectural changes within the corium and laminae were readily seen at 4.7 T, and there was a strong association with the histologic diagnosis of active laminitis. Measurements obtained with MR imaging were more sensitive and specific predictors of laminitis than those obtained radiographically. Subjective evaluation with MR imaging was more sensitive than with radiography and should become more specific with greater understanding of normal anatomy.

Follistatin gene delivery enhances muscle growth and strength in nonhuman primates.

Antagonists of myostatin, a blood-borne negative regulator of muscle growth produced in muscle cells, have shown considerable promise for enhancing muscle mass and strength in rodent studies and could serve as potential therapeutic agents for human muscle diseases. One of the most potent of these agents, follistatin, is both safe and effective in mice, but similar tests have not been performed in nonhuman primates. To assess this important criterion for clinical translation, we tested an alternatively spliced form of human follistatin that affects skeletal muscle but that has only minimal effects on nonmuscle cells. When injected into the quadriceps of cynomolgus macaque monkeys, a follistatin isoform expressed from an adeno-associated virus serotype 1 vector, AAV1-FS344, induced pronounced and durable increases in muscle size and strength. Long-term expression of the transgene did not produce any abnormal changes in the morphology or function of key organs, indicating the safety of gene delivery by intramuscular injection of an AAV1 vector. Our results, together with the findings in mice, suggest that therapy with AAV1-FS344 may improve muscle mass and function in patients with certain degenerative muscle disorders.

Results of excision of thymoma in cats and dogs: 20 cases (1984-2005).

OBJECTIVE: To provide long-term follow-up information for a series of dogs and cats with invasive and noninvasive thymomas treated by excision alone. DESIGN: Retrospective case series. ANIMALS: 9 cats and 11 dogs with thymoma. PROCEDURES: Medical records were reviewed. The following factors were analyzed for their effect on prognosis: age of dog or cat, invasiveness of the tumor, percentage of lymphocytes in the mass (percentage lymphocyte composition) on histologic evaluation, and mitotic index of the mass. RESULTS: All patients were treated with excision of the tumor alone. Median overall survival time for the cats was 1,825 days, with a 1-year survival rate of 89% and a 3-year survival rate of 74%. Median overall survival time for the dogs was 790 days, with a 1-year survival rate of 64% and a 3-year survival rate of 42%. Recurrence of thymoma was observed in 2 cats and 1 dog, and a second surgery was performed in each, with subsequent survival times of 5, 3, and 4 years following the first surgery. Percentage lymphocyte composition of the mass was the only factor that was significantly correlated with survival time; animals with a high percentage of lymphocytes lived longer. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study indicated that most cats and dogs with thymomas did well after excision. Even cats and dogs with invasive masses that survived the surgery and the few cats and dogs with recurrent thymomas or paraneoplastic syndromes had a good long-term outcome. Excision should be considered an effective treatment option for dogs and cats with thymomas.

Osteogenic gene regulation and relative acceleration of healing by adenoviral-mediated transfer of human BMP-2 or -6 in equine osteotomy and ostectomy models.

This study evaluated healing of equine metatarsal osteotomies and ostectomies in response to percutaneous injection of adenoviral (Ad) bone morphogenetic protein (BMP)-2, Ad-BMP-6, or beta-galactosidase protein vector control (Ad-LacZ) administered 14 days after surgery. Radiographic and quantitative computed tomographic assessment of bone formation indicated greater and earlier mineralized callus in both the osteotomies and ostectomies of the metatarsi injected with Ad-BMP-2 or Ad-BMP-6. Peak torque to failure and torsional stiffness were greater in osteotomies treated with Ad-BMP-2 than Ad-BMP-6, and both Ad-BMP-2- and Ad-BMP-6-treated osteotomies were greater than Ad-LacZ or untreated osteotomies. Gene expression of ostectomy mineralized callus 8 weeks after surgery indicated upregulation of genes related to osteogenesis compared to intact metatarsal bone. Expression of transforming growth factor beta-1, cathepsin H, and gelsolin-like capping protein were greater in Ad-BMP-2- and Ad-BMP-6-treated callus compared to Ad-LacZ-treated or untreated callus. Evidence of tissue biodistribution of adenovirus in distant organs was not identified by quantitative PCR, despite increased serum antiadenoviral vector antibody. This study demonstrated a greater relative potency of Ad-BMP-2 over Ad-BMP-6 in accelerating osteotomy healing when administered in this regimen, although both genes were effective at increasing bone at both osteotomy and ostectomy sites.

Metacarpophalangeal collateral ligament reconstruction using small intestinal submucosa in an equine model.

Xenogeneic porcine small intestinal submucosa (SIS) is a natural, biodegradable matrix that has been successfully used as a scaffold for repair of tissue defects. The goal of this study was to compare a collateral ligament transection surgically reconstructed with an anchored SIS ligament to a sham-operated control procedure for the correction of joint laxity using an equine model. Ten metacarpophalangeal joints from 10 horses had complete transection of the lateral collateral ligament. In 6 horses, the collateral ligament was reconstructed with a multilaminate strip of SIS anchored with screws into bone tunnels proximal and distal to the joint. The sham controls had similar screws, but no SIS placed. Clinical compatibility and effectiveness were evaluated with lameness, incisional quality, and joint range of motion, circumference and laxity. Ligament structure and strength was quantified with serial high resolution ultrasound, histology, and mechanical testing at 8 weeks. Surgical repair with SIS eliminated joint laxity at surgery. SIS-treated joints had significantly less laxity than sham treatment at 8 weeks (p < 0.001). SIS-treated ligaments demonstrated a progressive increase in repair tissue density and fiber alignment that by week 8 were significantly greater than sham-treated ligament (p < 0.03). SIS-repaired ligament tended to have greater peak stress to failure than sham-treatment (p < 0.07). Cellularity within the ligament repair tissue and inflammation within the bone tunnel was significantly greater in the SIS-treated limbs (p < 0.017). Within the first 8 weeks of healing, SIS implanted to reinforce collateral ligament injury was biocompatible in the joint environment, restored initial loss of joint stability, and accelerated early repair tissue quality. SIS ligament reconstruction might provide benefit to early ligament healing and assist early joint stability associated with ligament injury.

Variation in gross and histological appearance of the canine pars flaccida.

The tympanic membrane is divided into the pars flaccida (PF) and pars tensa. Otoscopic differences in the appearance of the PF in the dog (flat vs. bulging) have been reported anecdotally. The purpose of this study was to histologically examine the canine PF to determine if differences exist between a flat and a bulging PF. We hypothesized that differences in the PF may be structural or due to an increased pressure in the middle ear. Four adult canine cadavers were used (two had bilateral bulging PF, two had bilateral flat PF). The ear specimens were fixed in 10% buffered neutral formalin, decalcified, routinely processed and stained with haematoxylin and eosin, toluidine blue (staining for mast cells), and Verhoeff-van Gieson (staining for elastic fibres). One blinded investigator evaluated each PF histologically. Seven ears (three with bulging PF, four with flat PF) were evaluated in the study. The PF was identified in all seven ears. No histological differences that distinguished a bulging PF from a flat PF were identified. Six ears were evaluated for the presence of mast cells and elastic fibres. Less than one mast cell per x40 field was identified in the PF in five of six ears. No elastic fibres were identified in any of the six PF. Based on the results of this study, it appears unlikely that there is a structural difference that accounts for a bulging PF. Therefore, there may be increased middle ear pressure in dogs with a bulging PF.

Subchondral bone density and cartilage degeneration patterns in osteoarthritic metacarpal condyles of horses.

OBJECTIVE: To evaluate and correlate patterns of subchondral bone density and articular cartilage degeneration (derived by use of gross, histologic, and computed tomographic [CT] examinations) in equine third metacarpal condyles with and without osteoarthritis. SAMPLE POPULATION: 8 metacarpophalangeal (MCP) joints (n = 4 horses) without osteoarthritis and 6 osteoarthritis-affected MCP joints (4). PROCEDURES: Horses were euthanized. The third metacarpal condyles of the joints were examined grossly and via CT (3 slice images/condyle). For 6 condylar zones, mean bone density and pattern of density distribution were determined. Data for osteoarthritis-affected and control joints were compared. Histomorphometric point count analyses identified areas of bone density for comparison with CT density measurements. RESULTS: Osteoarthritis-affected condyles had heterogeneous subchondral bone with focal resorptive lesions and patterned sclerosis, whereas control condyles had symmetric bone density distribution. In osteoarthritis-affected condyles, bone density determined via gray scale image density analysis was greater (dorsal and medial pattern), compared with control condyles, and differed among zones because of resorption and sclerosis. With regard to bone density in osteoarthritis-affected condyles, histologic findings correlated with CT images, and bone lesions were significantly correlated with cartilage lesions. CONCLUSIONS AND CLINICAL RELEVANCE: In horses, heterogeneous distribution and greater subchondral bone density were characteristic of osteoarthritis-affected condyles, compared with control condyles. Subchondral bone lesions correlated with overlying cartilage lesions in osteoarthritis-affected MCP joints. Identification of CT image characteristics appears to predict the presence of a cartilage lesion in MCP joints of horses with osteoarthritis.

Mesenchymal stem cell-mediated gene delivery of bone morphogenetic protein-2 in an articular fracture model.

In articular fractures, both bone and cartilage are injured. We tested whether stem cells transduced with bone morphogenetic protein 2 (BMP2) can promote bone and cartilage repair. Distal femoral articular osteotomies in nude rats were treated with stem cells, either wild-type or transduced with an adenoviral (Ad) BMP2. Cells were delivered in alginate (ALG) carrier or by direct injection in saline solution. Gene expression of these cells at the osteotomy site was confirmed by in vivo imaging. At day 14, only the group that received AdBMP2 stem cells by direct injection showed completely healed osteotomies, while other groups remained unhealed (P < 0.0003). In ALG groups, bone healing was impeded by the development of a chondroid mass, most pronounced in the AdBMP2 ALG group (P < 0.002). We were successful in achieving repair of both bone and cartilage in vivousing direct stem cell injection. Our data suggests that BMP2 augmentation might be critically important in achieving this effect.

Effects of a magnesium adhesive cement on bone stability and healing following a metatarsal osteotomy in horses.

OBJECTIVE: To compare biodegradable magnesium phosphate cement (Mg-cement), calcium phosphate cement (Ca-cement), and no cement on bone repair, biocompatibility, and bone adhesive characteristics in vivo in horses. ANIMALS: 8 clinically normal adult horses. PROCEDURES: Triangular fragments (1-cm-long arms) were created by Y-shaped osteotomy of the second and fourth metatarsal bones (MTII and MTIV, respectively). Fragments were replaced in pairs to compare Mg-cement (MTII, n = 8; MTIV, 8) with Ca-cement (MTIV, 8) or with no cement (MTII, 8). Clinical and radiographic evaluations were performed for 7 weeks, at which time osteotomy sites were harvested for computed tomographic measurement of bone density and callus amount, 3-point mechanical testing, and histologic evaluation of healing pattern and biodegradation. RESULTS: All horses tolerated the procedure without clinical problems. Radiographically, Mg-cement secured fragments significantly closer to parent bone, compared with Ca-cement or no treatment. Callus amount and bone remodeling and healing were significantly greater with Mg-cement, compared with Ca-cement or no cement. Biomechanical testing results and callus density among treatments were not significantly different. Significantly greater woven bone was observed adjacent to the Mg-cement without foreign body reaction, compared with Ca-cement or no cement. The Mg-cement was not fully degraded and was still adhered to the fragment. CONCLUSIONS AND CLINICAL RELEVANCE: Both bone cements were biocompatible in horses, and Mg-cement may assist fracture repair by osteogenesis and fragment stabilization. Further studies are warranted on other applications and to define degradation characteristics.

Rodent models for the study of articular fracture healing.

The goal of this study was to document the healing time course and expression of ex vivo cell-based gene delivery in articular fracture models in the mouse and rat. Articular medial intercondylar femoral osteotomy was performed in the stifle (knee) joints of hairless immunocompetent mice and medial or lateral similar osteotomy was performed in athymic nude rats. Genetically modified cells expressing luciferase were delivered in a three-dimensional alginate matrix directly into the osteotomy site. Sensitivity of an in vivo imaging system to detect expression of luciferase was compared between rodents in this fracture model. Osteotomy healing was assessed using high-detail radiography, helical computed tomography (CT), high-field magnetic resonance imaging, and histology. The mouse model was less satisfactory because the small size of the murine femur made reliable assessment of fracture healing restricted to histopathology, and complications occurred in 11/24 mice (45.8%), most frequently transverse supracondylar femoral fracture postoperatively. Gene expression was inconsistently confirmed in mice in vivo for 11 days (p < .003). In rats, high-detail radiography and CT were used to assess osteotomy healing. Magnetic resonance imaging (4.7 T) in rats could produce three-dimensional images that would permit assessment of bone and cartilage, but was time-consuming and expensive. In rats, the only surgical complication, transverse femoral fracture, was reduced from 83.3% with the medial osteotomy to 0% with a lateral osteotomy. In vivo imaging confirmed gene expression in the alginate/cell constructs in rats for at least 4 days (p < .05). The nude rat model has the advantage of larger femora and the ability to implant xenograft cells. A lateral intercondylar osteotomy of the distal femur in the rat can be used to study the healing of articular fractures.

A reproducible scoring system for quantification of histologic lesions of inflammatory disease in mouse gastric epithelium.

Comparison of experimental groups by microscopic examination is a common and useful method for evaluating animal models of disease. Quantification of lesions is challenging, however, and differences in scoring systems hinder comparison of results from different laboratories. The purpose of this study was to validate a simple and reproducible scoring system for Helicobacter pylori-associated gastric disease in mice. The system is based on quantification of the percentage of microscopic fields in which lesions are present, rather than on subjective estimates of lesion severity. Linear regression analyses revealed good agreement between investigators in scoring of all 3 histologic criteria examined. The range of correlation coefficients between individual readers' scores and mean scores for the 3 histologic criteria examined were: neutrophilic inflammation, 0.845 to 0.935; gastritis sufficient to displace glands, 0.919 to 0.943; and epithelial metaplasia, 0.650 to 0.799. Comparison of scores in different experimental groups by analysis of variance and Fisher least significant difference tests revealed significant differences between infected and uninfected groups and between immunodeficient and immunocompetent groups. We propose that this system may be useful in standardizing the morphologic evaluation of rodent models of H. pylori and that a similar system could be devised for evaluation of other animal models of enteric disease.