Facilitation of recovery from acute blood loss with hyperbaric oxygen.

Background: Hyperbaric oxygen (HBO) has been used for more than 25 years as therapy for extreme blood loss in cases where transfusion has been unavailable. The use of HBO for lesser amounts of blood loss to avoid the transfusion of blood products has not been investigated.

Hypothesis: Hyperbaric oxygen up-regulates hemoglobin synthesis after acute blood loss in an animal model of moderate (30%) blood loss.

Spontaneous disc degeneration in the baboon model: magnetic resonance imaging and histopathologic correlation.

Degenerative disc disease is a major source of disability in humans. The baboon model is an excellent natural disease model to study comparable human disease, because baboons are relatively large (adult males 20-26 kg, adult females 12-17 kg), long-lived (30-45 years), well defined, easy to use, and closely related to humans. Published investigations with plain radiographs of disc degeneration in baboons indicated vertebral anatomy and changes that were remarkably similar to those seen in humans, and it would be valuable to determine if magnetic resonance imaging (MRI) and histopathologic evaluation would be useful methods for studying the model, as MRI allows multi-planar visualization of tissues without the use of intravenous contrast and it is superior for evaluating disc hydration, annulus tears, and herniations.

Evaluation of multiphase implants for repair of focal osteochondral defects in goats.

The use of biodegradable scaffolds for articular cartilage repair has been investigated by numerous researchers. The objective of this screening study was to examine how the mechanical and physical properties of four multiphase implants can affect the cartilage healing response. Multiphase implant prototypes were prepared using poly(D,L)lactide-co-glycolide as the base material.

Bone morphogenetic protein but not transforming growth factor-beta enhances bone formation in canine diaphyseal nonunions implanted with a biodegradable composite polymer.

Background: The purpose of the present study was to create an effective bone-graft substitute for the treatment of a diaphyseal nonunion.

Methods: A standardized nonunion was established in the midportion of the radial diaphysis in thirty mongrel dogs by creating a three-millimeter segmental bone defect (at least 2 percent of the total length of the bone). The nonunion was treated with implantation of a carrier comprised of poly(DL-lactic acid) and polyglycolic acid copolymer (50:50 polylactic acid-polyglycolic acid [PLG50]) containing canine purified bone morphogenetic protein (BMP) or recombinant human transforming growth factor-beta (TGF-beta1), or both, or the carrier without BMP or TGF-beta1.

Osteochondral progenitor cells in acute and chronic canine nonunions.

This study examined the ability of cells isolated from early healing segmental defects and from tissue from chronic nonunions to support bone and cartilage formation in vivo and their response to transforming growth factor-beta1 in vitro. Ostectomies (3 mm) were created in the radial diaphysis of four dogs. The dogs were splinted 3-5 days postoperatively and then allowed to bear full weight.

TP53 overexpression in radiation-induced osteosarcoma of the rabbit mandible.

The objective of this study was to investigate the incidence of overexpression of TP53 (formerly known as p53) in osteosarcomas occurring after treatment of rabbit mandibles with high-dose external-beam radiation. As part of a protocol investigating hyperbaric oxygen treatment for osteoradionecrosis, 102 female New Zealand-White rabbits underwent mandibular radiation treatments with a total dose of 64 Gy in 20 treatment fractions. Twelve animals died during irradiation, leaving 90 animals at risk for tumor development.

"Mandibular and facial reconstruction" rehabilitation of the head and neck cancer patient.

Cancer surgery and its reconstruction today can result in functional and cosmetically supportive results for most patients. Today's better understanding of malignant tumor kinetics has evolved preservative and precision extirpative surgery which has on one hand enhanced cure rates and on the other hand has preserved function and appearance in such patients. Today's reconstructive techniques have a sound basis in wound healing and bone regeneration science so as to be predictable and long lasting.

Surgical correction of severe vaginal introital stenosis in female baboons (Papio sp.) infected with simian agent 8.

Simian agent 8 (SA8) is a neurotropic, endemic alphaherpesvirus in Papio sp. Lesions associated with simian agent 8 infections usually involve the genitalia of sexually mature baboons. In females, secondary bacterial infections may lead to scarring of the vulva and perineum, with resulting vaginal obstruction.

Total reconstruction of the temporomandibular joint with cryogenically preserved allograft mandibular condyle, meniscus, and fossa in the adult goat.

Objective: The purpose of this study was to determine the feasibility of total temporomandibular joint reconstruction with the use of cryogenically preserved allograft mandibular condyle, disk, and fossa in the adult goat.

Study Design: This study consisted of an experimental group of 10 adult goats that underwent total resection of their temporomandibular joints. These animals were immediately reconstructed with cryogenically preserved mandibular condyles, disks, and fossa.

Balloon angioplasty with stent implantation in experimental coarctation of the aorta.

Background: Balloon angioplasty of coarctation of the aorta is an effective method of treatment but is complicated by tearing of the aortic intima, formation of aneurysms, and restenosis. Stent placement at the time of balloon dilation could prevent restenosis and could also prevent progression of intimal tears to aneurysms. The purpose of this study was to evaluate the feasibility of balloon dilation and implantation of balloon-expandable stents in an experimental model of coarctation and to examine the effect of stent placement at the site of surgically created stenosis.

A comparison of the form and function of the human, monkey, and goat temporomandibular joint.

The anatomic form and function of the human temporomandibular joint is compared with the monkey (Macaca and Papio) and goat joint. The findings indicate that the joint of the goat seems to be superior to the joint of Macaca and Papio as a research model.

Re-expansion of balloon-expandable stents after growth.

Objectives: The purpose of this study was to evaluate the feasibility of re-expansion of balloon expandable intravascular stents and to examine the gross and histologic effects of re-expansion on vascular integrity.

Background: Intravascular stents have been used successfully as an adjunct to balloon dilation of congenital pulmonary artery branch stenosis and postoperative stenosis of the pulmonary arteries in children. However, use of rigid stents in children could result in development of relative stenosis at the site of stent implantation with subsequent growth of the child.

Intermittent gastric dilatation after gastropexy in a dog.

Gastroperitoneal adhesions, which developed after tube gastrostomy in a 3-year-old dog, caused an inverted L configuration of the pyloric antrum and duodenum, resulting in periodic episodes of gastric dilatation. The dog had undergone tube gastrostomy for treatment of gastric dilatation/volvulus, but gastropexy adhesions broke down 27 months later, necessitating a second pexy procedure. Adhesions then developed, constricting gastric outflow and trapping gas in the stomach and proximal duodenum.

Cardiopulmonary reference standards in the pregnant sheep (Ovis aries): a comparative study of ovine and human physiology in obstetrics.

1. Complete blood counts, respiratory rate, tidal volume, arterial and mixed venous blood gases; heart rate, cardiac output, and arterial, pulmonary artery, central venous and pulmonary wedge pressures were determined in 10 pregnant adult sheep of 42.7-65.

Relationship of oxygen dose to angiogenesis induction in irradiated tissue.

This study was accomplished in an irradiated rabbit model to assess the angiogenic properties of normobaric oxygen and hyperbaric oxygen as compared with air-breathing controls. Results indicated that normobaric oxygen had no angiogenic properties above normal revascularization of irradiated tissue than did air-breathing controls (p = 0.89).

Cryogenically preserved adult and juvenile goat mandibular condylar transplantation.

Loss of a functional temporomandibular joint (TMJ) has long been a clinical challenge in both children and adults. Although reconstruction to date has been performed with various prosthetic devices or autogenous costochondral grafts, these procedures have a potential for complications and morbidity. Our studies were performed to determine the feasibility of healing, growth, and long-term function of TMJ reconstruction techniques with cryogenically preserved mandibular allografts in the goat model.

Direct angioplasty of the basilar artery in baboons.

The lower portion of the basilar artery is a site of significant disease, both aneurysmal and stenotic, but has been considered inaccessible via traditional surgical approaches. A baboon model was used to evaluate the feasibility of a direct surgical reconstruction via a transoral-transclival approach, utilizing temporary occlusion of the basilar artery. An arteriotomy was performed and either repaired primarily or a venous patch graft was sutured in place.

Simulated nasoalveolar palatal defects: a canine model to study bone grafts.

A simple, surgical technique to create a simulated nasoalveolar palatal defect in the canine is described. The procedure has been performed in 60 canines, and we have not experienced closure of the created clefts. The surgically created clefts had to fulfill five criteria: (1) bilateral maxillary alveolar clefts had to exist in each research animal; (2) each cleft had to have a 1-cm bony width; (3) a demonstrable oronasal communication had to be present; (4) each cleft had to be lined by healthy epithelialized mucosa; (5) there had to be functional teeth adjacent to each side of every cleft.

Evaluation of Gore-Tex graft material in the repair of right ventricular outflow tract defect.

Following right ventriculotomy, Gore-Tex PTFE vascular grafts were placed in eight neutered male, 6- to 8-week-old, 8- to 12-kg pigs. Ten to 14 months after surgery each pig was evaluated by right heart catheterization. The swine were sacrificed and the hearts were evaluated grossly and microscopically.

Glutaraldehyde-fixed bovine pericardium for right ventricular outflow enlargement.

Right ventricular outflow tract enlargement using glutaraldehyde-fixed bovine pericardium was evaluated experimentally using the pig model. Twelve piglets (8-16 kg) underwent closure of surgically created, longitudinal right ventriculotomies using premeasured, round, bovine pericardial patches. Half of the animals had pulmonary artery banding to increase right sided pressures.

Preliminary observations on the effects of hyperbaric oxygen therapy on western diamondback rattlesnake (Crotalus atrox) venom poisoning in the rabbit model.

Intermittent hyperbaric oxygen therapy has been shown to reduce skeletal muscle necrosis in a compartment syndrome animal model. To study whether intermittent exposure to hyperbaric oxygen augments antivenin therapy in reducing muscle necrosis, we injected sublethal doses of Western Diamondback rattlesnake (Crotalus atrox) venom intramuscularly into the hind legs of New Zealand White rabbits. In this pilot study, the animals were divided into three treatment groups.

Cardiovascular hemodynamics in the swine following long-term placement of prosthetic grafts post right ventriculotomy.

1. Heart rate, cardiac output and arterial, pulmonary artery, central venous and pulmonary wedge pressures were measured in eight neutered male pigs of an average of 14 months of age and 145.0-231.

Transplantation of cryogenically preserved mandibular condyles in the adult and juvenile goat.

Loss of a functional temporomandibular joint (TMJ), due to various causes including tumor resection, joint disease such as osteonecrosis, and injury or trauma, has long been a clinical challenge in both children and adults. It may be a significant problem facing physicians during another war. While reconstruction to date has been performed with various prosthetic devices or autogenous costochondral grafts, these procedures have a potential for complications and morbidity.