Migration of cells from the yolk sac to hematopoietic tissues after in utero transplantation of early and mid gestation canine fetuses.

BACKGROUND: In utero hematopoietic cell transplantation offers a means of early intervention for the treatment of diseases before birth. Delivery of cells to the yolk sac is a minimally invasive approach that results in low levels of chimerism. However, there is little information on the optimal doses, timing of delivery, and migration of transplanted cells from the yolk sac into the fetus. METHODS: Varying cell doses of mesenchymal stromal cells or bone marrow mononuclear cells labeled with fluorescent supraparamagnetic iron oxide nanoparticles and a fluorescent intracellular dye, 5- and 6-([(4-chloromethyl)benzoyl]-amino) tetramethylrhodamine, were transplanted under ultrasound guidance to the yolk sacs of day 25 or day 35 canine fetuses. Ex vivo whole body fluorescence imaging and microscopy of tissue sections were correlated with the presence of iron oxide in injected and control fetuses. RESULTS: Day 25 and day 35 recipients showed similar survival rates after injection of cells into yolk sacs, although increased fetal morality was associated with cell doses greater than 10 cells/kg to day 25 fetuses. The fluorescence and iron oxide signals were predominantly localized to the abdominal regions, with no fluorescence visible in yolk sacs. Microscopy of tissues revealed colocalization of fluorophore with iron oxide in donor cells detected in the fetal livers and bone marrow of recipients 7 and 17 days after receiving mesenchymal stromal cells or bone marrow mononuclear cells. CONCLUSIONS: These studies demonstrated that cells injected into the yolk sacs of early gestation canine fetuses migrate to recipient hematopoietic tissues. Thus, yolk sac injection offers a safe and effective approach for engraftment of cells to fetal hematopoietic tissues.

Use of a circular external skeletal fixator for stabilization of a comminuted diaphyseal metatarsal fracture in an alpaca.

CASE DESCRIPTION: A 3-year-old male alpaca was evaluated because of non-weight-bearing lameness (grade 5/5) in the left hind limb. CLINICAL FINDINGS: Clinical and radiographic examination revealed a closed, comminuted, nonarticular, displaced diaphyseal fracture of the left third and fourth metatarsal bones. TREATMENT AND OUTCOME: Initial attempts at treatment via reduction of the fracture under traction and subsequent application of a cast were unsuccessful, and more stable fracture fixation was pursued. The alpaca underwent closed reduction of the fracture, which was stabilized by the application of a 3-ring circular external skeletal fixator (CESF). Improved weight bearing on the affected limb was evident soon after surgery and gradually increased; full weight bearing was evident by the seventh day after discharge from the hospital (day 20 after application of the CESF). Lameness was hardly noticeable during walking at that time. After 3 months, complete fracture healing was evident and the CESF was removed; mild outward rotation of the distal fragment and metatarsophalangeal joint was present. A Robert Jones bandage was applied to the limb, and the alpaca was kept in a stall for another 4 weeks. Eleven months after CESF application, the owners and referring veterinarian reported that the alpaca was healthy, not lame, and serving as a stallion without apparent impediment. CLINICAL RELEVANCE: Although mostly restricted to small animals, application of a CESF can be a viable alternative for management of long bone fractures in South American camelids.

Perioperative administration of antimicrobials associated with elective surgery for cranial cruciate ligament rupture in dogs: 83 cases (2003-2005).

OBJECTIVE: To evaluate perioperative antimicrobial use associated with elective surgery for cranial cruciate ligament rupture in dogs. DESIGN: Retrospective case series. ANIMALS: 83 dogs. PROCEDURES: Medical records were reviewed and antimicrobial use practices were evaluated for dogs with no other problems that would affect antimicrobial use decisions. RESULTS: Antimicrobials were administered before or during surgery to 75 of 83 (90%) dogs. Timing of administration with respect to first incision, intraoperative administration, and duration of administration were variable. Antimicrobial administration began after surgery in 3 (3.6%) dogs. Fifty-five of 65 (85%) dogs treated before surgery received the first dose within 60 minutes of the first incision. Time from first antimicrobial administration to closure of the incision ranged from 15 to 285 minutes (mean +/- SD, 141 +/- 53 minutes). If a guideline of repeated administration every 2 hours after first administration until closure of the surgical site was used, 22 of 43 (51%) dogs received the required intraoperative dose, whereas 6 of 32 (19%) dogs that did not require intraoperative treatment were treated. Twenty-four (29%) dogs received antimicrobials after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Certain discrepancies between antimicrobial use practices in this study and standard guidelines used in human medicine were evident.

Rehabilitation for the neurologic patient.

A properly designed rehabilitation program should be an important component of the treatment plan of animals with neurologic disease. Such a program should be designed in conjunction with appropriate treatment of the underlying problem and after special consideration of the origin of the neurologic problem, the severity of the signs, the cause of the signs, their anticipated progression, and the needs of the owner and the pet. This article describes the pathophysiology of injury and recovery in the central and peripheral nervous systems, assessment of the neurologic patient, data on the prognosis and expected course of recovery for a variety of different diseases, and rehabilitation exercises appropriate for neurologic patients.

Rehabilitation of medical and acute care patients.

Cancer and serious systemic illness result in several physiologic changes that involve multiple body systems. While the primary conditions are addressed with traditional modalities of medicine, the side effects, secondary changes, and complications can be ameliorated or even prevented with rehabilitation and supportive care. This article reviews problems facing the oncologic and critically ill animal, discusses basic techniques in the management of these animals, and highlights the essential role of rehabilitation in obtaining maximal functional capacity in the critically ill patient.

Evaluation of oxidative stress markers for the early diagnosis of allograft rejection in feline renal allotransplant recipients with normal renal function.

The purpose of this study was to identify oxidative damage to renal allografts during graft rejection by evaluating changes in oxidative markers and plasma lactate levels in feline renal allotransplant recipients. Heterotopic renal allotransplantations were performed between 8 adult feline cross-matched donors. Following 14 d of immunosuppression, the drugs were discontinued to allow allograft rejection. Baseline and serial postoperative evaluations of serum creatinine, plasma lactate, plasma thiobarbituate reactive substances (TBARS), plasma creatol, urine creatol, and renal sonographic cross-sectional area were performed. When sonographic evaluation revealed the absence of blood flow to the allograft, the rejected kidney was nephrectomized and evaluated histopathologically. Allograft rejection occurred in all cats by day 26. A significant elevation in body temperature occurred during the rejection period. No significant change was observed between any of the time periods for plasma TBARS, creatol, or urine creatol. There was a significant decrease in plasma lactate levels throughout the study. Markers of oxidative stress from venous blood did not reflect renal allograft rejection in cats with a normally functioning native kidney. Renal allograft rejection may be associated with significant increases in body temperature and warrants further investigation.

Biomechanical comparison of a circular external skeletal fixator construct to pin and tension band wire fixation for the stabilization of olecranon osteotomies in dogs: a cadaveric study.

OBJECTIVE: To compare anatomic reduction and the biomechanical properties of a circular external skeletal fixator (CESF) construct to pin and tension band wire (PTBW) fixation for the stabilization of olecranon osteotomies in dogs. STUDY DESIGN: Cadaveric study. ANIMALS: Forelimbs from 12 skeletally mature mixed-breed dogs, weighing 23 to 28 kg. METHODS: An olecranon osteotomy was stabilized with either a CESF construct or PTBW fixation. A single distractive load to failure was applied to each specimen through the triceps tendon. Osteotomy reduction and biomechanical properties were compared between fixation groups. RESULTS: Reduction was not significantly different (gap: P =.171; malalignment: P =.558) between fixation groups. Osteotomies stabilized with the CESF had greater stiffness (P <.0001) and maximum load sustained (P <.0001) compared to PTBW fixation. There was no significant difference for yield load (P =.318) or for load at 1 mm of axial displacement (P =.997) between fixation groups. Failure of fixation occurred by bending of the intramedullary Steinmann pin and the fixation wires in the CESF specimens and by untwisting of the tension band wire knot with pullout and bending of the Kirschner wires in the PTBW specimens. CONCLUSIONS: Specimens stabilized with the CESF construct had similar reduction and yield load, greater stiffness and maximum load sustained, and less elastic deformation than specimens stabilized with PTBW fixation. CLINICAL RELEVANCE: The CESF construct may provide a biomechanically favorable alternative to PTBW fixation for stabilization of olecranon osteotomies in dogs, and its application warrants clinical investigation.

Sonographic and scintigraphic evaluation of acute renal allograft rejection in cats.

The sonographic features of acute renal allograft rejection in humans and dogs are manifested by increase in renal cross-sectional area and reduction in renal cortical blood flow. These changes have not been investigated in cats. The objectives of this study were to evaluate sonographic and scintigraphic changes during acute renal allograft rejection in cats. Eight SPF, intact, adult, male cats received heterotopic renal allotransplantations. Immunosuppressive doses of cyclosporine and prednisolone were administered for 14 days and then discontinued to allow acute allograft rejection to occur. Serial measurements of renal cross-sectional area, resistive index (RI), echogenicity, and glomerular filtration rate (GFR) were performed to evaluate changes during acute rejection. Upon sonographic confirmation of absent diastolic blood flow or a 20% increase in cross-sectional area of the allograft, a nephrectomy and histopathologic evaluation were performed. Acute allograft rejection was confirmed histologically in all cats. Significant increases in renal cross-sectional area (P < 0.001) occurred postoperatively and during rejection. There were no significant changes in RI (P = 0.43) at any time. A subjective increase in medullary echogenicity and a decrease in corticomedullary demarcation were observed in the rejection period. While GFR decreased significantly in the immediate postoperative period (P < 0.001), no further change occurred during rejection (P = 0.42). Changes in RI and GFR do not appear to be sensitive indicators of acute renal allograft rejection in cats. Serial measurements of renal cross-sectional area appear to be a sensitive method for the early diagnosis of allograft rejection in feline renal transplant recipients.

Complication rate and factors affecting outcome of olecranon osteotomies repaired with pin and tension-band fixation in dogs.

The objective of this study was to determine the complication rate and evaluate factors affecting the outcome of olecranon osteotomy in dogs. Medical records were searched to identify dogs that had undergone olecranon osteotomy (stabilized with 2 Kirschner wires and a figure-of-8 wire) during internal fixation of a supracondylar or condylar humeral fracture. Signalment, description of the fracture, parameters regarding the osteotomy and its repair, and radiographic outcome were recorded. A logistic regression model compared patient and technical parameters with the osteotomy outcome. Of the 19 dogs, 7 (37%) had complications of the osteotomy, including osteomyelitis, loss of reduction, and improper placement and migration of the Kirschner wires. Olecranon osteotomy is associated with a high complication rate in dogs; however, there was no correlation between patient-related or technical parameters and the development of complications. Further clinical and biomechanical investigations are warranted to improve the results of olecranon osteotomy and its repair.

Use of IMEX SK-circular external fixator hybrid constructs for fracture stabilization in dogs and cats.

Complex long-bone fractures with short juxta-articular fracture segments can be difficult to manage. Recently, IMEX Veterinary, Inc., began producing titanium hybrid rods that can be secured to ring components of the IMEX circular external skeletal fixation system to create SK-circular hybrids. In this case series, SK-circular hybrids were used to stabilize long-bone fractures (two femoral, one humeral, and three tibial fractures) with short distal bone segments in three dogs and three cats with body weights ranging from 1.9 to 15 kg (mean, 6.7 kg; median, 5.4 kg). Although three cases required surgical revision, animals ambulated well and all fractures obtained union. Time to radiographic union ranged from 62 to 137 days (mean, 90 days; median, 84 days). The functional outcome was considered excellent in all six cases.