The biomechanical and biological effect of supercooling on cortical bone allograft

BACKGROUND

The need for a storage method capable of preserving the intrinsic properties of bones without using toxic substances has always been raised. Supercooling is a relatively recently introduced preservation method that meets this need. Supercooling refers to the phenomenon of liquid in which the temperature drops below its freezing point without solidifying or crystallizing.

OBJECTIVES

The purpose of this study was to identify the preservation efficiency and applicability of the supercooling technique as a cortical bone allograft storage modality.

METHODS

The biomechanical effects of various storage methods, including deep freezing, cryopreservation, lyophilization, glycerol preservation, and supercooling, were evaluated with the three-point banding test, axial compression test, and electron microscopy. Additionally, cortical bone allografts were applied to the radial bone defect in New Zealand White rabbits to determine the biological effects. The degree of bone union was assessed with postoperative clinical signs, radiography, micro-computed tomography, and biomechanical analysis.

RESULTS

The biomechanical properties of cortical bone grafts preserved using glycerol and supercooling method were found to be comparable to those of normal bone while also significantly stronger than deep-frozen, cryopreserved, and lyophilized bone grafts. Preclinical research performed in rabbit radial defect models revealed that supercooled and glycerol-preserved bone allografts exhibited significantly better bone union than other groups.

CONCLUSIONS

Considering the biomechanical and biological superiority, the supercooling technique could be one of the optimal preservation methods for cortical bone allografts. This study will form the basis for a novel application of supercooling as a bone material preservation technique.

Novel Achilles Tendon Repair Technique Utilizing an Allograft and Hybrid External Fixator in Dogs

Background:

Achilles mechanism rupture is a surgical condition involving primary tenorrhaphy with various described means of surgical augmentation and bolstering.

Aim:

To report complications and outcomes with a novel Achilles repair technique in dogs using a superficial digital flexor tendon (SDFT) or deep digital flexor tendon (DDFT) allograft.

Methods:

Medical records were reviewed for dogs with chronic rupture or deterioration of the Achilles mechanism. Fibrous tissue was excised and either primary tenorrhaphy or reattachment of the tendon(s) to the calcaneus was performed. The surgical repair was supplemented by an SDFT or DDFT allograft, and postoperative immobilization was provided using a transarticular hybrid external skeletal fixator. Complications were classified as minor, major, or catastrophic, and function was classified as full, acceptable, or unacceptable, based on established guidelines.

Results:

Complications occurred with 6 out of 12 repairs, including 1 minor, 6 major, and 2 catastrophic complications. The two catastrophic complications were the recurrence of tarsal hyperflexion and lameness at 20 weeks and 18 months following surgery. Of the 12 surgeries performed, 2 resulted in full function, 8 with acceptable function, and 2 with unacceptable function at last follow-up 17–98 weeks postsurgery (mean = 45 weeks) for a success rate of 10/12 cases.

Conclusion:

The use of SDFT or DDFT allografts, coupled with an external fixator, can provide a moderate rate of full or acceptable functional outcomes and appears a viable treatment. However, complications were frequent and without a comparison group no conclusions can be drawn about the inferiority or superiority of this technique to other techniques for Achilles mechanism repair in dogs.

Testicular subcutaneous allografting followed by immunosuppressive treatment promotes maintenance of spermatogonial cells in rainbow trout (Oncorhynchus mykiss)

Germ cell transplantation and testis graft represent promising biotechnologies that can be applied for the reproduction of commercial or endangered species. However, mechanisms of rejection from the host immune system might remove the transplanted donor cells/tissues and limit the surrogate production of gametes. In this work, we administered emulsion containing-immunosuppressants to verify whether they are capable to prevent immune rejection and promote survival of testis allografts in rainbow trout. In the first part of this study, we demonstrated in vitro that tacrolimus and cyclosporine were able to affect viability, inhibit leucocyte proliferation, and suppress il2 expression in vitro. In in vivo experiments, both doses of tacrolimus (0.5 and 1.5 mg/kg) and the lower dose of cyclosporine (20 mg/kg) significantly inhibited the expression of il2 in head kidney, three days post-injection. A higher dose of cyclosporine (40 mg/kg) was able to inhibit il2 expression for up to seven days post-injection. In the second part, testis allografts were conducted in fish treated weekly with emulsion containing-tacrolimus. Immunohistochemical, conventional histology, and qRT-PCR (vasa) analysis demonstrated the presence of spermatogonial cells by the fifth week, in animals treated with 0.5 mg/kg of tacrolimus similar as found in autografted group. In the group treated with the highest tacrolimus dose (1.5 mg/kg) and in the non-treated group (without immunosuppressant), no germ cells or their respective markers were detected. il2 expression in head kidney was also suppressed in grafted animals treated with tacrolimus compared to non-treated group. These results suggest that tacrolimus may be a promising immunosuppressant for testis allografts or germ cell transplantation in rainbow trout. Co-administration combining tacrolimus (at lower dose) with other immunosuppressive drugs for inhibiting other activation pathways of the immune system, as performed in human organ transplantation, could be an alternative approach to optimize the immunosuppressive effects in host organisms.

Genome and transcriptome analyses providing insight into the immune response of pearl oysters after allograft and xenograft transplantations

The immune response after allograft or xenograft transplantation in the pearl oyster is a major factor that cause its nucleus rejection and death. To determine the mechanism underlying the immune response after allograft and xenograft transplantations in the pearl oyster Pinctada fucata martensii, we constructed two sets of transcriptomes of hemocytes at different times (6 and 12 h; 1, 3, 6, 12, and 30 d) after allograft and xenograft transplantations, in which the xenografted mantle tissue was from Pinctada maxima. The transcriptomic analysis reveals many genes are involved in the immune response to transplantation, such as transient receptor potential cation channel (TRP), calmodulin (CaM), DNA replication-related genes, and sugar and lipid metabolism-related genes. The expression of these identified genes was higher in the host pearl oyster transplanted with xenograft than that by allograft. The histological analysis of the pearl sac also confirmed that many hemocytes were still gathered around the transplanted nucleus, and no pearl sac was formed in the host pearl oysters at 30 d after xenograft transplantation. The genomic analysis indicated that pearl oysters evolved many copies of genes, such as TRP, CaM, and GST, to sense and cope with the immune response after transplantation. "Ribosome" and "Cytosolic DNA-sensing pathway" were specifically induced in the xenograft group, whereas "Notch signaling pathway" specifically responded to the allograft transplantation. These results can improve our understanding of the mechanism underlying the immune response of pearl oysters after allograft and xenograft transplantations.

Surgical management of long bone fractures in cats using cortical bone allografts preserved in honey

This report describes comminuted fractures in 2 cats repaired by stabilization with cortical bone allografts that had been preserved in honey. Both cats exhibited appropriate post-operative weight-bearing. Preservation of bone in honey is a simple and widely available alternative for bone banking. This is the first report of a bone defect in cats repaired with bone preserved in honey.

Transcriptome responses of duodenal epithelial cells to prolactin in pituitary-grafted rats

Chronic prolactin (PRL) exposure can affect several functions of duodenal epithelia, especially those associated with fluid and electrolyte transport. However, little is known regarding its molecular mechanism. To identify PRL-regulated genes, microarray analysis was performed on RNA samples from duodenal epithelial cells of anterior pituitary (AP)-grafted hyperprolactinemic rats. Herein, we identified 321 transcripts upregulated and 241 transcripts downregulated after 4 weeks of AP transplantation. Results from real-time PCR analyses of 15 selected genes were consistent with the microarray results. Gene ontology analysis demonstrated pleiotropic effects of PRL on several cellular processes, including cellular metabolic process, cell communication and cell adhesion. Interestingly, 17 upregulated transcripts and 12 downregulated transcripts are involved in the transport of ions and nutrients, e.g., Ca(2+), Na(+), K(+), Cl(-) and glucose, thus agreeing with the established action of PRL on electrolyte homeostasis. The present results provided fundamental information for further investigations on mechanism of PRL actions in the intestine.

Application of osteochondral autografts and allografts in the treatment of articular cartilage lesions in animals

The paper describes current views on the use of osteochondral autografts and allografts in the treatment of articular cartilage lesions in animals. It presents surgical techniques of grafting and the biological features of osteochondral auto- and allografts, and their effect on the recipient's cartilage.

Use of Capecitabine to Prevent Acute Renal Allograft Rejection in Dog Erythrocyte Antigen-Mismatched Mongrel Dogs

OBJECTIVE

To assess efficacy and toxicity of a capecitabine (CAP)-based regimen for preventing rejection of renal allografts in dog erythrocyte antigen (DEA)-mismatched mongrel dogs.

STUDY DESIGN

Prospective, pilot study.

ANIMALS

Eight healthy, unrelated, DEA mismatched, adult mongrel dogs.

METHODS

All dogs received CAP, starting at 50 mg/m2 PO b.i.d. 4 days preoperatively, increasing to 200 mg/m2 PO b.i.d. by the day of surgery. All dogs received cyclosporine-A (CsA) and prednisolone starting 2 days preoperatively. Standard heterotopic renal transplantation with native nephrectomy was performed. After 90 days, surviving dogs were euthanatized and histopathologic examination was performed.

RESULTS

Two of 8 dogs developed acute neurotoxicity leading to death or euthanasia within 5 days of surgery. For the 6 remaining dogs, there were no statistically significant changes in complete blood count or serum biochemical values. No opportunistic infections developed during the study period. Five of 6 dogs had no to minimal evidence of graft rejection. Two of 6 dogs developed superficial and pigmentary keratitis. Significant histopathologic findings in all dogs included mild lymphoplasmacytic gastroenteritis, steroid hepatopathy, and corneal epithelial thinning. One dog had moderate interstitial nephritis and pyelitis.

CONCLUSIONS

In this experimental model, a CAP-CsA-prednisolone immunosuppressive regimen was effective in preventing rejection of allografts in DEA-mismatched dogs. Severe, unpredictable neurotoxicity and variable ocular toxicity significantly limit clinical applications at this time.

CLINICAL RELEVANCE

A CAP-CsA-prednisolone protocol is an effective, oral immunosuppressive regimen for prevention of allograft rejection in DEA-mismatched mongrel dogs. For clinical application, identification of patients susceptible to toxic side effects would be necessary.

Results of clinical renal transplantation in 15 dogs using triple drug immunosuppressive therapy

OBJECTIVE

To evaluate outcome of renal transplantation in dogs administered cyclosporine, azathioprine, and prednisolone immunosuppression.

STUDY DESIGN

Prospective clinical study.

ANIMALS

Fifteen dogs with chronic renal failure.

RESULTS

Nine dogs died within 1 month of surgery; 5 died from complications associated with generalized thromboembolism. Three dogs survived for 6-25 months. Three dogs alive at the time of this report have survived 22-48 months; however, all 3 dogs have had bacterial infections that responded to antibiotic therapy. There was no biochemical evidence of acute allograft rejection in any dog. Perioperative use of enoxaparin may have prevented thromboembolism in 5 dogs.

CONCLUSIONS

Triple drug immunosuppressive therapy used in this study prevented acute renal allograft rejection in 6 dogs that survived >4 weeks; however, immunosuppression was excessive, resulting in an unacceptable frequency of infection and other drug-related complications. Perioperative anticoagulation therapy seem to be warranted.

CLINICAL RELEVANCE

Survival time and quality of life for this group of dogs was poor; however, there was no evidence of acute rejection in the dogs surviving >4 weeks. This protocol should only be used if the degree of immunosuppression is reduced, and early evidence of allograft rejection is monitored by renal biopsy or markers of lymphocyte activation.

Use of multigeneration-family molecular dog leukocyte antigen typing to select a hematopoietic cell transplant donor for a dog with T-cell lymphoma

CASE DESCRIPTION

A 7-year-old Golden Retriever was examined because of anorexia, lethargy, vomiting, and gradual weight loss.

CLINICAL FINDINGS

Splenomegaly, pancytopenia, high serum calcium concentration, and high alkaline phosphatase activity were detected. Magnetic resonance imaging revealed an enlarged mesenteric lymph node and increased signals from the bone marrow of the ilium and vertebral bodies. Histologic examination and immunophenotyping of biopsy specimens confirmed a stage V (b) T-cell malignant lymphoma.

TREATMENT AND OUTCOME

Clinical remission was attained by use of 2 chemotherapy cycles, followed by an allogeneic hematopoietic cell transplant performed at 18 weeks after diagnosis. A donor was identified by molecular dog leukocyte antigen typing methods. The patient was conditioned with 2 fractions of 4 Gy total body irradiation delivered 3 hours apart at 7 cGy/min, followed by an IV infusion of recombinant canine granulocyte colony-stimulating factor mobilized leukapheresis product and postgrafting immunosuppression with cyclosporine. Chimerism analyses revealed full donor engraftment that has been maintained for at least 58 weeks after transplant. Remission has been confirmed by normal results of serum thymidine kinase assays and the absence of peripheral blood clonal T-cell receptor gene rearrangements.

CLINICAL RELEVANCE

Systemic chemotherapy induces remissions; however, most dogs succumb to disease recurrence because of multidrug resistance. Outcome of allogeneic hematopoietic cell transplantation in dogs can be excellent because of improved donor-recipient selection by use of molecular dog leukocyte antigen typing, compared with early attempts, and better prevention of graft versus host disease, better supportive care, and substitution of peripheral blood mononuclear cells for bone marrow.

Allograft theory: transmission of devil facial-tumour disease

The Tasmanian devil, a large carnivorous Australian marsupial, is under threat from a widespread fatal disease in which a malignant oral-facial tumour obstructs the animal's ability to feed. Here we show that the chromosomes in these tumours have undergone a complex rearrangement that is identical for every animal studied. In light of this remarkable finding and of the known fighting behaviour of the devils, we propose that the disease is transmitted by allograft, whereby an infectious cell line is passed directly between the animals through bites they inflict on one another.

Renal Allograft Histopathology in Dog Leukocyte Antigen Mismatched Dogs After Renal Transplantation

OBJECTIVE

To evaluate allograft histopathology in dog leukocyte antigen (DLA)-mismatched dogs undergoing renal transplantation, with transient immunosuppression.

STUDY DESIGN

Prospective study.

ANIMALS

Ten healthy adult mongrel dogs.

METHODS

Reciprocal renal transplantation and bilateral nephrectomy were performed. Immune conditioning consisted of nonmyeloablative (200 cGy), total body irradiation (TBI), bone marrow transplantation (BMT; 7 dogs), cyclosporine (CSA; 15 mg/kg every 12 hours), mycophenolate mofetil (MMF; 10 mg/kg every 12 hours) and intermittent prednisone (1 mg/kg every 12-24 hours). Biopsies were collected at transplantation, during full immunosuppression (44-90 days), and once medications were reduced or discontinued (228-580 days). Biopsies were evaluated for interstitial, tubular, vascular, and glomerular lesions. Blood urea nitrogen, creatinine, serum CSA concentrations, and clinical score were determined at each biopsy.

RESULTS

Seven dogs survived >200 days (mean, 380 days). Transient CSA toxicity was suspected in 6 dogs. Lymphocytic, plasmacytic interstitial inflammation, and tubulitis progressed when immunosuppressive medications were decreased. All 7 dogs had histologic lesions consistent with some degree of allograft rejection at study end.

CONCLUSION

Nonmyeloablative TBI, BMT, and short-term immunosuppression with CSA, MMF, and prednisone allowed renal allograft function and dog survival for >200 days. It appears unlikely that total drug withdrawal will be possible in unrelated DLA-mismatched dogs using this protocol.

CLINICAL RELEVANCE

Transient immunosuppression with MMF, CSA, and prednisone along with BMT and nonmyeloablative TBI may make kidney transplantation a clinical reality for treatment of kidney failure in dogs. Initiating both MMF and CSA at lower dosages may potentially eliminate early renal allograft injury.

Use of Capecitabine After Renal Allograft Transplantation in Dog Erythrocyte Antigen-Matched Dogs

OBJECTIVES

To investigate the use of a capecitabine (CAP)-based regimen after renal transplantation in dogs.

STUDY DESIGN

Prospective, pilot study.

ANIMALS

Healthy, unrelated, dog erythrocyte antigen (DEA)-matched, adult beagles.

METHOD

Standard heterotopic renal transplantation with native nephrectomy was performed in 7 dogs. Dogs received oral, twice daily, CAP (250 mg/m2), cyclosporine-A (CsA) (4 mg/kg), ketoconazole (5 mg/kg), and prednisolone (0.25 mg/kg). After 90 days the surviving dogs were euthanatized and complete necropsy was performed.

RESULTS

Seven transplants were performed. All dogs survived surgery. Six dogs had acute neurotoxicity, which resulted in death or euthanasia of 2 dogs within 2 days of surgery. In the remaining dogs, toxicity resolved rapidly with cessation of drug administration. Thereafter, modification of the regimen minimized toxicity. The 5 remaining dogs survived to study end; 4 dogs had no evidence of graft rejection. Necropsy examination was mostly unremarkable in all dogs. There were no major changes in CBC or biochemical values, except for a significant increase in serum calcium.

CONCLUSIONS

CAP appeared well tolerated in most dogs. Toxicity occurred but abated with modification of the drug regimen. Efficacy for postoperative immunosuppression cannot be determined by this study, although results are promising.

CLINICAL RELEVANCE

CAP-CsA-prednisolone is an effective, oral immunosuppressive regimen for prevention of acute allograft rejection in DEA-matched beagles. Further studies on dose, toxicity, and efficacy compared with current immunosuppressive regimens are needed before use in clinical practice.

Evaluation of healing in feline femoral defects filled with cancellous autograft, cancellous allograft or Bioglass

Cancellous bone grafting is a widely accepted technique in human and veterinary orthopaedic surgery. However, the use of autogenous bone graft is limited by the additional surgical time required to harvest the graft, the morbidity associated with the donor site, and the limited availability of cancellous bone, especially in feline patients. Various allografts and bone graft substitutes are available commercially but have not been fully evaluated for efficacy in the cat. The purpose of this study was to compare the incorporation of autogenous and allogenous cancellous bone graft and Bioglass, a synthetic bone graft substitute, in femoral defects in cats. Four (4.0 mm diameter) defects were created in the lateral diaphyseal cortex of the left femur with an orthopaedic drill. In each femur, one of the cortical defects was filled with autogenous cancellous graft (harvested from the tibia), one was filled with allogenic cancellous graft, and one was filled with Bioglass. The fourth defect remained unfilled. Graft incorporation within the femoral defects was evaluated by radiographic evaluation every two weeks. Six weeks after the grafting procedure, the cats were euthanatized and high detailed radiography, dual energy X-ray absorptiometry (DEXA), histopathology and histomorphometry of the defects were performed. Satisfactory bone healing was observed within all of the defects.

Orthotopic transplantation of rat ovaries as a tool for strain rescue

Spontaneous mutations in inbred strains provide valuable resources for new disease models. Unfortunately, these mutations may affect reproduction, which require considerable efforts in breeding management. We transplanted ovaries of such mutant rat strains orthotopically into ovariectomized premature coisogenic recipients. A reproductive cycle was established in each of the recipients within 5 to 6 weeks after transplantation. Moreover, one-third became pregnant and had litters an average of 3 months after transplantation. These experiments demonstrate that orthotopic transplantation of ovaries can be used in the management of subfertile rat colonies.

Acellular and Glutaraldehyde-Preserved Tendon Allografts for Reconstruction of Superficial Digital Flexor Tendon in Bovines: Part II - Gross, Microscopic and Scanning Electron Microscopic Observations

Sixteen tenorrhaphies were performed at mid-metatarsal region in eight buffalo calves. A 2-cm long gap was created in the superficial digital flexor (SDF) tendon in all animals. The gap was immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II, and in group III the defect was repaired with autografts (control group). The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Gross observation revealed filling of host tendon-graft junction with fibrous connective tissue. Increased vascularity was seen in group I when compared with group II and III. Graft was resorbed in animals of group I and III, whereas partial absorption of graft was seen in group II. Histological observations on day 30 revealed restoration of cellularity in acellular graft and fragmentation and resorption of glutaraldehyde-preserved graft. Graft was replaced by newly formed fibrous connective tissue. Tissue reaction around polygalactin suture consisted of plasma cells, lymphocytes and macrophages. On day 90, most of the acellular graft was replaced by newly formed fibrous connective tissue. In group II the majority of graft portion remained at the site and was in a state of resorption. In the control group it was difficult to distinguish between the host tendon and the graft. Scanning electron microscopical observation showed densely packed neoformed tissue at host tendon-graft junction. Hydrolysis and invasion of connective tissue between polygalactin suture filaments, resorption of graft with cavity formation and dissolution of ground substance were observed.

Acellular and Glutaraldehyde-Preserved Tendon Allografts for Reconstruction of Superficial Digital Flexor Tendon in Bovines: Part I - Clinical, Radiological and Angiographical Observations

Sixteen tenorrhaphies were performed at the mid-metatarsal region in eight buffalo calves under lignocaine epidural analgesia. A 2 cm long gap was created in the superficial digital flexor (SDF) tendon and immediately repaired with acellular grafts in animals of group I, 1% glutaraldehyde-preserved tendon allografts in group II. In group III, the defect was repaired with autografts. This group served as control. The contralateral limb in each animal was operated after an interval of 60 days and the animals underwent the same procedure according to the designed groups. Diclofenac sodium and Enrofloxacin was given post-operatively for 5 days. Clinical examination revealed significant increase (P < 0.05) in rectal temperature, heart and respiratory rate for 3-4 postoperative days in all the animals. Mild pain and exudation as well as early restoration of tendon gliding movements and weight-bearing were observed earlier in group I in comparison with group II. Air-tendograms revealed early organization, minimal adhesion formation and lesser thickening of tendon at the reconstructive site in the acellular group whereas in the glutaraldehyde group dense homogenous swelling with adhesions was seen along the flexors. Angiography on day 30 showed that the area of proximal and distal host tendon graft junction appeared hypervascularized, whereas the area occupied by the graft appeared relatively less vascularized. Normal vascularization was observed on day 90 in all the three groups.

Cylindrical press-fit osteochondral allografts for resurfacing the equine metatarsophalangeal joint

OBJECTIVE

To investigate the feasibility of resurfacing the equine fetlock joint using cylindrical, orthotopic, press-fit, osteochondral allografts.

STUDY DESIGN

Experimental study.

ANIMALS

Ten mature, mixed-breed horses.

METHODS

Cylindrical, osteochondral grafts (6.5-mm diameter) were harvested aseptically from cadaveric equine metatarsophalangeal joints. Allografts were transplanted into 6 horses; 4 horses were sham operated. The surgical approach involved creation of a bone block at the origin of the medial collateral ligament and luxation of the metatarsophalangeal joint. Grafts were placed into the medial and lateral metatarsal condyles. Radiographs were taken at 8 and 25 weeks, and lameness was evaluated at 25 weeks. Horses were killed at 25 weeks. Analyses included gross evaluation, microradiography, paravital staining, light microscopy, and cartilage biochemistry.

RESULTS

No complications occurred that could be attributed to the surgical procedure. Graft congruency with the surrounding articular cartilage was fair to excellent. Two horses were sound at 25 weeks. Most grafts had more than 90% articular cartilage coverage, and histologic and microradiographic analysis revealed good graft incorporation and articular cartilage survival. Sulphated glycosaminoglycan concentration was decreased in grafted tissue.

CONCLUSIONS

We attribute the viability of osteochondral allografts in the equine fetlock to adequate congruency, stable graft fixation, and the use of orthotopic tissue. Host response to the allograft bone tissue did not affect cartilage viability.

CLINICAL RELEVANCE

Before clinical use, improvements to instrumentation are required that would decrease damage to grafts and minimize technique-associated incongruencies of the articular surface at the time of grafting. Larger grafts would also likely be required to resurface a greater surface area.

Optimal protocol for total body irradiation for allogeneic bone marrow transplantation in mice

We have previously demonstrated, using chimeric resistant MRL/lpr mice, that a fractionated total body irradiation (FTBI) (5 Gy x 2 with a 4 h interval on the day before allogeneic bone marrow transplantation (BMT)) is the best conditioning regimen for the treatment of autoimmune diseases in radiosensitive MRL/lpr mice. In the present study, using various standard strains of mice (not radiosensitive mice), we explore the best protocol for irradiation (doses and intervals) as the conditioning regimen for allogeneic BMT. Recipient mice were exposed to various irradiation regimens: a single total body irradiation (TBI) of 9.5 or 12 Gy and FTBI of (5+5) Gy to (7+7) Gy with a 1 to 24 h interval. The method generally utilized for humans ((2+2) Gy with a 4 h interval for 3 days (total 12 Gy)) was also used. One day after the last irradiation, donor BMCs from BALB/c, C3H, or C57BL/6 (B6) mice were transplanted into C3H or B6 mice. The irradiation protocol of (2+2) Gy for 3 days was found to be insufficient to enable the complete removal of recipient immunocompetent cells, since donor-reactive T cells were observed in the recipient spleens and many recipient-type NK and CD4(+) cells were also detected in the recipient hematolymphoid tissues. In all the combinations, the highest survival rate was achieved in the recipients irradiated with (6+6) or (6.5+6.5) Gy with a 4 h interval. In the surviving mice, the hematolymphoid tissues had been fully reconstituted with donor cells.

Graft-versus-host reaction (GVHR) in clonal amago salmon, Oncorhynchus rhodurus

The graft-versus-host reaction (GVHR) was demonstrated in a salmonid model system of clonal diploid and triploid amago salmon. Triploid operculum grafts on clonal diploid evoked an acute rejection within 12 days. Grafts exchanged among triploid amago salmon exhibited prolonged survival for 18 days. In contrast, diploid grafts on triploid, and allografts among clonal diploid amago salmon were accepted. A typical GVHR was induced in triploid recipients by intraperitonal injection of head kidney cells from sensitised diploid donors. The clinical signs of graft-versus-host disease (GVHD) were observed in the recipients after 1 week of cell injection as a loss of appetite and appearance of solid faeces, followed by haemorrhage, local swelling of ventral skin and an enlarged spleen. Three of six fish died within 1 month. Water temperature and frequency of sensitisation are critical to induce GVHR. Diploid donors had to be sensitised three times at 20 degrees C to induce the typical GVHR. GVHR was most effectively induced by head kidney cells, followed by peripheral blood leucocytes (PBL) and spleen cells. Ploidy analysis by flow cytometry revealed that the donor head kidney cells greatly increased in the recipient liver, head kidney and spleen, and reached the peak after 9 days of donor cell injection. The results in the present study are quite similar to the findings in ginbuna and ginbuna-gold fish hybrid system, suggesting the presence of T cells in salmonid as well as cyprinid fish.

Carbon fibres and plasma-preserved tendon allografts for gap repair of flexor tendon in bovines: gross, microscopic and scanning electron microscopic observations

The efficacy of carbon fibres and plasma-preserved tendon allografts for gap repair in the superficial digital flexor tendon in the mid-metatarsal region was evaluated in 12 crossbred calves. Experimental tenectomies were performed, followed by implantation of carbon fibres in group I (12 legs) and plasma-preserved tendon allografts in group II (12 legs). Gross observations in group I showed filling of the defect with granulation tissue with more vascularity on day 7, which was less prominent at day 14. On day 30, the neotendon formed was slightly thicker and comparable to normal tendon in appearance and texture. On day 90, it exhibited all the characteristics of a fully developed tendon. Whereas, in group II increased vascularity at the site and encapsulation of the graft with connective tissue in early periods was observed. The gap between graft and host was filled with fibrous connective tissue. Peritendinous adhesions were maximum on day 7 which were gradually reduced in both groups. Microscopically, an acute inflammatory reaction in the periphery of carbon fibres was observed on day 7. Immature fibroblasts were arranged in a haphazard pattern at this stage. By day 14, numerous newly formed capillaries and comparatively more mature fibroblasts were present in between and around the carbon fibres which were aligning parallel to the longitudinal axis of the tendon. By day 30 the healing tissue exhibited longitudinal orientation of collagen fibres and was at a more advance stage of maturation. By day 90, the neotendon formed simulated the picture of normal tendon. In the grafted tendon group, there was normal healing tissue at the functional sites between host and grafted tendon. The fibroblastic activity appeared to be both extrinsic and intrinsic in origin. The connective tissue had invaded the graft to a variable distance and there was resorption of graft which was replaced by newly formed connective tissue on day 90. Scanning electron microscopic observation revealed formation of neotendon between carbon fibre strands, resulting in thickening of the implant. In later stages parallel collagen fibres resembling normal tendon were observed in both groups.

Safety of percutaneous ultrasound-guided biopsy of renal allografts in the cynomolgus monkey: results of 348 consecutive biopsies

The safety of a technique for ultrasound-guided biopsy of renal allografts was evaluated based on 348 consecutive procedures in cynomolgus monkeys. A spring-loaded biopsy device with an 18G tru-cut biopsy needle was used to biopsy renal allografts in 139 cynomolgus monkeys performed either on clinical indication (n = 95 animals) or as serial protocol biopsies (n = 44 animals) for a total of 348 biopsies. Monkeys having serial biopsies received between 3-9 biopsies per animal. All others received non-protocol biopsies that were performed on clinical indication, and the range was 1-15 biopsies per animal. No life-threatening complications or deaths occurred and there were no clinically detectable minor complications such as macrohematuria. Self-limiting complications such as small arteriovenous fistulas (n = 4, 3-5 mm large) were detected with Doppler ultrasound and resolved hemodynamically after 2-4 weeks. Three animals developed hematomas ranging 4 mm-2 cm in diameter and were no longer sonographically evident 2-4 weeks later. Ultrasound-guided biopsy of renal allografts can be performed with a high degree of safety in small (3-5 kg) laboratory animals such as the cynomolgus monkey and provides a valuable tool for renal transplantation research. Even when cores were taken at two week intervals no major complications occurred and only rarely were clinically irrelevant complications detected. Experience with diagnostic ultrasound, both gray scale and Doppler, is important for both safety and the recognition of complications that may arise.

Bone allografts and adjuvant cisplatin for the treatment of canine appendicular osteosarcoma in 18 dogs

The results achieved in 18 dogs following the use of frozen bone cortical allografts for limb-sparing resection of non-metastatic canine appendicular osteosarcoma are presented. Three to five cisplatin doses (70 mg/m2) were administered, starting the day after surgery. The mean and median survival times were 478 and 266 days (range 80 to 2,611 days), respectively. The survival rate was 94 per cent at three months, 78 per cent at six months, 35 per cent at 12 months, 23 per cent at 18 months and 19 per cent at 24 months; the disease-free interval was 80 to 1,246 days (mean 365 days, median 266 days). Lung metastasis developed in 55 per cent of the dogs within one year. Complications were observed in 14/18 dogs (78 per cent), comprising local recurrence (28 per cent), allograft infection (39 per cent) and implant failure (11 per cent). Despite complications, limb sparing is a useful alternative to amputation in selected cases of appendicular osteosarcoma.

Effects of a 98% solution of glycerol or sterilization with ethylene oxide on FeLV in bone allografts and effects on bone incorporation of allografts in cats

OBJECTIVES

To compare virucidal effects and bone incorporation properties of cortical bone allografts transplanted into specific-pathogen-free (SPF) cats. Allografts consisted of untreated bone from a SPF cat (negative-control group) and bone from 5 FeLV-infected cats that was subjected to sterilization with ethylene oxide (ETO), preservation with glycerol, or no treatment (positive-control group).

SAMPLE POPULATION

Bones from the aforementioned groups and twenty 8-week-old SPF cats (5 cats/group) implanted with an allograft from 1 of the aforementioned groups.

PROCEDURE

After implantation, blood samples were collected weekly to monitor FeLV p27 antigen and antibody titers. Quantification of FeLV provirus was performed on blood samples at weeks 0, 4, and 8 and donor bone samples at time of implantation. Cats were euthanatized 8 weeks after transplantation, and graft sites were evaluated.

RESULTS

All results for negative-control cats were negative. All ETO group cats had negative results for antigen and provirus in blood, whereas 1 cat had a low antibody titer. Although 3 ETO-treated allografts were positive for provirus, the DNA appeared denatured. One cat in the glycerol group had positive results for all tests in blood samples. All glycerol-preserved allografts were positive when tested for provirus. All results for positive-control group cats were positive. Differences in incorporation of bone grafts were not observed.

CONCLUSIONS AND CLINICAL RELEVANCE

Glycerol preservation of FeLV-infected bone allografts did not eliminate transmission of retrovirus to recipients. In contrast, ETO sterilization appeared to denature DNA and prevent infection. Treatments did not affect incorporation of bone grafts in young cats.

Ultrasonographic evaluation of renal autografts in normal cats

The purpose of this study was to determine changes in resistive index (RI) and renal size that occur in normal feline kidney autografts in the immediate post-transplant period. Qualitative changes in renal parenchymal echogenicity and pelvic dilation were also noted, although this was not a major focus of the study. Fourteen domestic short-haired cats underwent bilateral nephrectomies followed by an autograft of the right kidney to either the aorta or external iliac artery. Due to post-operative complications, only nine of these cats completed the study. Ultrasonographic determination of the RI and renal size was made before transplantation and on days 1, 4, 7, 10, and 13 following transplantation. No significant changes in renal RI were identified during the study. Renal size increased significantly, peaking at 63% above baseline on day 7, and stayed elevated at 50% above baseline on day 13. There was no evidence of rejection or other abnormalities found on histologic evaluation of the transplanted kidneys. It was concluded that the RI of normal feline renal autografts does not significantly change in the immediate post-operative period. However, significant renal enlargement, likely due to a combination of post-operative edema and hypertrophy, does occur. This study provides baseline information for comparison with feline allografts in the immediate post-transplant period.

A comparison of transdermal fentanyl versus epidural morphine for analgesia in dogs undergoing major orthopedic surgery

Postoperative analgesia provided by transdermal fentanyl was compared with that provided by epidural morphine in dogs undergoing major orthopedic surgery. Dogs randomly were assigned to receive either a 100 microg per hour transdermal fentanyl patch 24 hours prior to surgery (n=8) or epidural morphine (0.1 mg/kg body weight) administered following induction of anesthesia (n=10). Temperature, heart rate, respiratory rate, and pain score were recorded prior to surgery and zero, six, 18, 30, and 42 hours after surgery. Blood samples were collected from the dogs in the transdermal fentanyl group beginning 24 hours preoperatively to 42 hours postoperatively. Fentanyl concentrations were determined by radioimmunoassay. When all time periods after surgery were combined, dogs in the transdermal fentanyl group were experiencing significantly less pain after surgery than dogs given epidural morphine. The transdermal fentanyl provided analgesia after major orthopedic surgery greater than or equivalent to that of epidural morphine.

Limb salvage surgery for osteosarcoma of the proximal humerus: outcome in 17 dogs

OBJECTIVE

To describe function and identify factors that affect outcome in dogs undergoing limb salvage surgery for osteosarcoma (OS) of the proximal humerus.

STUDY DESIGN

A retrospective study of dogs in which OS of the proximal humerus was treated with limb salvage surgery.

ANIMALS

17 client-owned dogs.

METHODS

Records were analyzed for functional outcome, recurrence, metastasis, and survival.

RESULTS

Outcome was good to excellent in 12% of dogs. Recurrence, metastasis, and survival were significantly affected by completeness of surgical margins. Double plating of the distal allograft-host junction significantly reduced frequency of biomechanical failure.

CONCLUSIONS

Limb salvage surgery for OS of the proximal humerus did not result in acceptable function and was fraught with postoperative complications. Outcome was significantly affected by completeness of surgical margins.

CLINICAL RELEVANCE

Limb salvage surgery for OS of the proximal humerus in dogs cannot be recommended until improvement in functional outcome and reduction in postoperative complications can be achieved. The dependence of outcome on completeness of surgical margins supports aggressive en bloc resection and marking and evaluating surgical margins.

Clinical renal allograft transplantation in a Dalmatian dog: case report

A case of successful renal allograft transplantation performed in a two-year-old female Dalmatian dog suffering from end-stage chronic renal failure is reported. A one-year-old male German shepherd with severely injured spinal cord was used as kidney donor. Simultaneous kidney allograft transplantation combined with hypothermic initial perfusion as graft conservation was done, placing the donor kidney into the right iliac fossa of the recipient. The immunosuppression protocol consisted of prednisolone and azathioprine. Regular physical, laboratory, ultrasonographic and scintigraphic examinations were used for assessing both the morphology and the function of the allograft. After a two-week period of hospitalisation the patient was discharged in a remarkably improving condition. The recipient died on postoperative day 45 of respiratory insufficiency resulting from secondary pneumonia and pulmonary oedema. Neither macroscopic nor microscopic abnormalities of the allograft were revealed by necropsy.

Renal transplants in cats: 66 cases (1987-1996)

OBJECTIVE

To document the morbidity and survival time after renal transplants in cats with end-stage renal failure.

DESIGN

Retrospective case series.

ANIMALS

66 cats that had renal transplants.

PROCEDURE

Information regarding signalment, history, diagnostic testing, and postoperative morbidity and mortality was retrieved from medical records of cats with renal failure that had renal transplants at the University of California School of Veterinary Medicine between 1987 and 1996.

RESULTS

47 of 66 (71%) cats that had renal transplants survived until discharge. Nineteen cats died in the perioperative period. Most common causes of death were seizure-related complications (7 cats) and renal pedicle complications (4). One discharged cat was unavailable for follow-up monitoring. Of the 46 cats discharged and available for follow-up monitoring, 28 died. Most common causes of death in these cats were renal complications (9 cats) and death related to immunosuppression (8; mean and median survival times, 15 and 12 months, respectively). Of the 18 cats that were still living at the time this report was written, mean and median survival times were 26 and 22 months, respectively.

CLINICAL IMPLICATIONS

Renal transplantation resulted in long-term survival of many cats that would have otherwise died from, or have been euthanatized as a result of, renal failure. Problems with ureteral obstruction can be minimized. Postoperative CNS disorders were the most prevalent complication.

Use of full cortical allograft to repair a metatarsal fracture in a foal

A 4-month-old Quarter Horse colt was admitted for repair of an open, comminuted fracture of the proximal portions of the diaphyses of the left second, third, and fourth metatarsal bones. Initial repair included internal fixation and cancellous bone graft. However, the third metatarsal bone became infected and failed to heal. After removal of infected portions of the bone, a 5-cm, fullthickness cortical allograft was placed in the defect. Rigid internal fixation provided stability for the allograft and remaining fracture fragments so that the horse was able to bear weight on the second and fourth metatarsal bones. The allograft was ultimately resorbed; however, appositional bone growth permitted a massive, functional metatarsal bone to form that incorporated the second, third, and fourth metatarsal bones. The colt went on to compete successfully, long term, as a show horse.

Central nervous system disorders after renal transplantation in cats

OBJECTIVE

This study describes the incidence and severity of postoperative central nervous system (pCNS) disorders in feline renal transplant recipients.

STUDY DESIGN

A retrospective study based on the medical records of cats that received renal allografts from 1987 to 1996.

ANIMALS OR SAMPLE POPULATION

Fifty-seven client-owned cats received renal allografts for the treatment of renal failure.

METHODS

The frequency, duration, severity, and treatment of episodes of pCNS disorders were recorded from the medical records.

RESULTS

Twelve (21%) of 57 cats had pCNS disorders 1 hour to 5 days after the surgical procedure. Seven cats survived; four had single or multiple seizure episodes, and two had seizure episodes or disorientation followed by a period of coma. One cat became temporarily ataxic and blind after restraint for venipuncture. Five cats died; all had episodes of disorientation or seizures, or both, that progressed to a nonrecoverable comatose state, respiratory arrest or cardiac arrest, or both. There were no significant differences between the two groups in preoperative serum creatinine, blood urea nitrogen, or cholesterol levels, and intraoperative blood pressure measurements. There were no significant differences in the postoperative serum glucose levels, electrolytes levels, or osmolality between the two groups. The cats with pCNS disorders had a mean preoperative trough cyclosporine A (CyA) whole blood level of 429 ng/mL; cats without pCNS disorders had a significantly (P = .0116) higher mean preoperative trough CyA whole blood level of 736 ng/mL.

CONCLUSION

Central nervous system disorders are a common and often fatal complication of renal transplantation in cats.

CLINICAL RELEVANCE

Recognition of pCNS disorders, and possible causes, will help develop hypotheses to investigate the problem.

Cranioplasty after en bloc resection of calvarial chondroma rodens in two dogs

The clinical features of chondroma rodens in two dogs and the treatment using radiation therapy, en bloc resection of the tumours and cranioplasties with a bone allograft (case 1) and a polymethylmethacrylate implant (case 2) are described. The dogs were still alive with no local recurrence of the tumours 30 and 18 months, respectively, after surgery. En bloc resection and calvarial reconstruction in the treatment of chondroma rodens are discussed.

Fate of allogeneic skin transplantations in a marsupial (Monodelphis domestica)

Previously we reported that the South American gray short-tailed opossum, Monodelphis domestica, had an MHC class-I locus similar to that of eutherian species. In addition to the detection of lymphocyte antigens by cytotoxic antisera, we concluded that this marsupial rejected allogeneic skin grafts, as would be expected of animals with MHC class-I polymorphism. However, this conclusion was based on a limited number of skin transplants that were assayed for only a short period. Here we report the results of 22 reciprocal skin grafts made between individuals of known genetic relationships. On the basis of gross inspection of the grafts and histologic examination, we found that the average time of the onset of graft rejection was about 19 days and that the average time for complete graft rejection was about 31 days. In general, it took longer for the onset of graft rejection among pairs of genetically related animals than among less related animals. These results indicate unequivocally that this marsupial species has a high degree of class-I polymorphism and rejects allogeneic skin transplants in a manner similar to but more slowly than eutherian mammals.

Homologous testis transplantation in dogs

There is growing interest in the possible use of homologous testis transplantation for the treatment of anorchia and male infertility. In order to test the surgical and immunological feasibility of this therapy, three series of experimental studies of homologous testis transplantation were carried out in dogs. In the first pilot study, four beagles from the same litter were transplanted using microsurgical techniques for end-to-end anastomosis of the testicular vessels and the vas deferens. These dogs received cyclosporin A (CyA) for 3 months after transplantation. The longest functional graft survival in this series was 163 days, strongly suggesting that long-term survival of a homologously transplanted testis graft is possible. A second series of operations was performed on ten mongrel dogs. The same surgical technique was employed and the series was divided into three groups. Group 1 received CyA monotherapy, group 2 a combination of CyA and prednisolone, and group 3 received no immunosuppression. The average graft survival time in this series was 28 days, significantly less than the 71 days in the first series. The dogs in group 2, however, had graft survival times that were three times longer than those in the other two groups, suggesting that CyA in combination with prednisolone yields the best graft survival. In the third series, five littermates received a testis graft after castration. Immunosuppression was achieved by administration of CyA and prednisolone for 3 months. In three out of five animals, the graft survived until the immunosuppressive therapy was suspended. Histological biopsies of the graft 3 months after transplantation showed the same maturation of sperm cells as in the control testis of the same dog. The results of the last series suggest that long-term survival of homologously transplanted testis grafts in dogs is, indeed, possible with the aid of CyA and prednisolone.

Acceptance of skin grafts by isogenic rainbow trout (Oncorhynchus mykiss)

OBJECTIVE

To test the immunocompetence of isogenic families of rainbow trout by measuring their ability to accept or reject skin grafts.

ANIMALS

3 families of isogenic rainbow trout (Oncorhynchus mykiss), produced by mating homozygous females and homozygous males, plus 4 chinook salmon (O tshawytscha) were used in these experiments.

PROCEDURE

Grafts (allografts, members of the same family; autografts, donor and recipient were the same fish; and xenografts, O tshawytscha as donor) were exchanged. Grafts were applied on day 0 and removed on day 21, placed in neutral-buffered formalin, and embedded in paraffin. Lymphocytes and nuclei were counted in representative stained sections in the epidermis, dermis, and hypodermis. Results were analyzed by univariate analysis, using the Shapiro-Wilk statistic.

RESULTS

Autografts were retained and minimal histologic changes were apparent. Allografts were histologically similar to autografts. Xenografts were rejected.

CONCLUSIONS

Results indicate that the immune system of isogenic rainbow trout is unable to distinguish between family members within isogenic families, but that a vigorous response is mounted against chinook salmon xenografts. The isogenic rainbow trout are immunocompetent with respect to the phenomenon of graft rejection.

Allogeneic marrow transplantation in a cat with acute myeloid leukemia

A listless, anorectic 2-year-old cat was found to have a normocytic, nonregenerative anemia. A diagnosis of acute myeloid leukemia type M6Er was made. Because the cat was young, had negative FeLV and feline immunodeficiency virus test results, had a sibling that could be used as a bone marrow donor, had received only 1 transfusion, and was in good health other than being anemic, allogeneic bone marrow transplantation (BMT) was attempted using marrow from the cat's sibling. The most life-threatening complication following BMT was hemorrhage caused by severe thrombocytopenia. Complete hematopoietic engraftment was evident 36 days after BMT. The cat then was discharged to its owner. In the first year, the cat continued to improve with the exception of an intractable dermatophytosis, which resolved eventually. The cat continues to do well 4 years after BMT. To our knowledge, this represents the first report of successful allogeneic BMT for a cat with acute myeloid leukemia.

Canine deciduoma induced by intralumenal insertion of uterine grafts

This report deals with evaluation of histological characteristics of the canine deciduoma induced by insertion of the uterine grafts as a biological stimulus. Autografts induced severe uterine cystic endometrial hyperplasia, and the grafts were organized by maternal endometrium. On the other hand, allografts induced more severe hyperplasia of the uterine endometrium with stronger inflammation than autografts. Almost all allografts became necrotic and lytic in the uterine lumen. These results suggest that uterine grafts could induce deciduoma and that the maternal endometrium, though under the functional corpora lutea, recognized the uterine grafts to be a stimulant and showed severe cystic endometrial hyperplasia.

Uterine carcinomas in mother cats after intrafetal inoculation of allogeneic tumor cells (K248 C and P)

Three out of 13 queens that had undergone injection of tumor cells from an allogeneic feline mammary carcinoma cell line through the wall of the pregnant uterus developed a carcinoma of the uterus. The possible role of immune tolerance associated with pregnancy and/or major histocompatibility complex (MHC) compatibility is discussed.

Renal allograft survival in outbred mongrel dogs using rabbit anti-dog thymocyte serum in combination with immunosuppressive drug therapy with or without donor bone marrow

Therapeutic renal transplantation in dogs is currently being investigated as a treatment for endstage renal disease. This pilot study examines the effect of donor bone marrow (DBM) infusion and antithymocyte serum (ATS) in combination with immunosuppressive drug therapy in prolonging renal allograft survival in dogs. Seven normal outbred mongrel dogs received an unmatched renal allograft. All dogs received rabbit anti-dog thymocyte serum (RADTS), prednisone (Pr), cyclosporine-A (CsA) and azathioprine (Aza). In addition, three dogs (group 1 test) received DBM and four dogs (group 2 control) did not receive DBM. Serum CsA levels were measured throughout the study. Immunosuppressive therapy was gradually reduced with Pr, CsA, and Aza withdrawn at 200, 450, and 680 days, respectively. Allograft rejection was treated with prednisolone sodium succinate. One dog in group 1 and one in group 2 died as a result of infectious canine rhinotracheitis and rejection early in the study. Renal allograft torsion occurred in one group 1 dog. The remaining four dogs survived the 2 years of the study. The dogs in group 2 (three dogs) all rejected the renal allograft after total drug withdrawal, the surviving dog in group 1 did not. This study demonstrates that RADTS, Pr, CsA, and Aza in combination can prolong renal allograft survival in mongrel dogs, whereas DBM may enhance the unresponsive state.

Evaluation of canine cortical bone graft remodeling

A stable cortical bone fracture model was developed to evaluate the remodeling rate of cortical bone grafts. Samples of cortical bone were harvested with a trephine and press fit into predrilled holes in the femoral diaphyses of four live dogs. The percentages of new bone, unremodeled graft bone, porosity, forming bone surface area, and resorbing bone surface area were determined morphometrically and compared in cortical autografts, cortical allografts sterilized with 84% ethylene oxide (EO), and allografts sterilized with 12% EO. The host-graft interfaces healed without formation of fibrous tissue or cartilage, indicating a stable fracture surface. The amount of new bone formed in cortical autografts and allografts sterilized with 84% EO was significantly greater than the amount of new bone in allografts sterilized with 12% EO. There was no significant difference between the amounts of new bone formed in the allografts sterilized with 84% EO and the cortical autografts. No significant differences were detected in percentages of porosity or bone surface areas.

Incorporation of Fresh and Cryopreserved Bone in Osteochondral Autografts in the Horse

The structural integrity of subchondral bone in fresh and frozen osteochondral autografts was investigated at month 3 in 10 horses. Two osteochondral autografts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. Grafts were frozen in 7.5% DMSO. After 14 days, the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifles. A fresh graft from the right hock was implanted in each left stifle. To control for the effects of surgery, a fresh graft was transferred from the right stifle to the left stifle. The end result was two grafts in each femoropatellar joint. Fresh and frozen bone grafts maintained a structurally intact support for the cartilage surface. Graft stability and surface congruency were determining factors in the outcome of the grafts. Incorporation of both types of graft was complete at month 3, but remodeling of the fresh grafts was more active.

Epiglottic augmentation in the horse

Epiglottic augmentation with injectable bovine collagen or an autogenous or allogenous auricular cartilage graft was performed in 12 horses with endoscopically and radiographically normal epiglottises. The grafting procedures were easy to perform and did not cause apparent discomfort. Cartilage graft extrusion or resorption may have occurred, but was not seen by endoscopy and lateral laryngeal radiography. Only collagen implants remained evident endoscopically, as smooth round submucosal bulges ventral to the epiglottic cartilage. Two horses with collagen implants, and all horses with cartilage autografts and allografts, were euthanatized at week 16. One horse with a collagen implant was euthanatized at week 4 and one at week 6. The epiglottis appeared thickened in three horses with collagen implants, two horses with autogenous grafts, and three horses with allogenous grafts. Pharyngeal lymphoid tissue was hyperplastic in two horses with autografts and three horses with allografts, but not in horses with collagen implants. Collagen grafts persisted as one or two smooth bulges 8 mm in diameter. Collagen incited a brisk foreign body reaction that was surrounded by a fibrous connective tissue capsule. Epiglottises of the horses with collagen implants were significantly thicker 20 mm from the tip than those of normal horses and horses with allografts. Cartilage graft incorporation was not evident grossly and was seen on microscopic examination in only one autograft. Thickening was caused by submucosal fibrosis.

Long-term survival of a cat receiving a renal allograft from an unrelated donor

A 6-year-old, spayed female Persian cat in terminal renal failure was referred to the Veterinary Medical Teaching Hospital for renal transplantation. An allograft from an unrelated donor was placed in the right iliac fossa and cyclosporine and prednisolone were administered as immunosuppressive agents. More than 18 months after surgery the cat was clinically normal and azotemia was absent.

Evaluation of full cortical allografts in 25 dogs

Twenty-five dogs received 26 cortical allografts from Apr 9, 1976 through Jan 31, 1982. Cortical allografts were used to reconstruct fractures of the femur, humerus, tibia, radius, and ulna. These grafts were used to replace comminuted fragments; to lengthen bones; to correct malunions, delayed unions, and nonunions; and in one case, to replace bone lost to sequestrum formation in an infected fracture site. All fractures were stabilized by use of standard ASIF techniques and dynamic compression plates. Frozen bone allografts were used in all cases. These were harvested aseptically and stored in a household freezer for 3 days to one year before use. Clinically normal function was achieved in 96% of the dogs.

Feline model for the study of frozen osteoarticular hemijoint transplantation: qualitative and quantitative assessment of bone healing

Twenty-four outbred cats underwent massive osteoarticular allograft and control autograft transplantation, using the right distal femur with its articular cartilage, capsule, and medial collateral ligament intact. The cats were monitored clinically and radiographically for 1 year. Groups of cats (4 allografts and 2 control autografts) were euthanatized at 3-, 6-, 9-, and 12-month intervals. At necropsy, the grafts were photographed and assessed for bone healing and replacement by standard radiography, quantitative 99mTc bone scans, microradiography, and histologic examination of decalcified and nondecalcified specimens. The osteosynthesis site of the allografts usually healed by 5 months, compared with the autografts that healed by 3 months. As illustrated by quantitative bone scans, creeping appositional new bone slowly invaded and replaced the allograft bone. Seemingly, the cat can be used as an acceptable and clinically comparable model for the massive osteoarticular allografts currently being used for the reconstruction of joints damaged or destroyed by neoplasm surgery in limb-sparing procedures in human beings. This model may also be used to assess the rate and method of bone healing.

Preliminary study of ethylene oxide sterilization of full-thickness cortical allografts used in segmental femoral fracture repair

Full-thickness canine cortical allografts were cleanly harvested, sterilized with ethylene oxide, and stored at room temperature. The allografts were incorporated into canine segmental femoral fracture repairs and compared clinically, radiographically, and morphologically with control femoral cortical autografts for function of the limb, graft acceptance, and bone union. Sterility was maintained and the cortical allografts were well accepted by the host animals, resulting in full use of the limb which was subjected to surgical operation. The allografts showed healing patterns similar to those of the autografts, as determined by radiographic, gross, and histologic evaluation of the proximal and distal host-graft interfaces. Evaluations were made monthly. The host-graft interfaces of the allografts and autograft were filled with woven bone with adjacent vascular invasion and remodeling of the graft at the final 4th-month evaluation.