Effect of Excess Fluoride Exposure on Radiographic and Histopathological Changes in Long Bones of Rabbit

The present study aimed to investigate the effects of excess fluoride exposure on long bones in young rabbits (Oryctolagus cuniculus). New Zealand White rabbits (n = 30) were randomly divided into five equal groups and were provided drinking water containing 0, 50, 100, 200, and 400 µg added fluoride per ml ad lib for a period of 90 days. Blood samples were collected on days 0, 45, and 90 of the experiment, and femur samples were collected for fluoride estimation on day 90 after radiography of long bone before sacrifice. Study revealed significant increase in serum fluoride concentration following oral intake of excess fluoride. Alterations in activities of alkaline phosphatase, aspartate transaminase, alanine transaminase, and concentrations of creatinine and urea nitrogen in blood plasma were also recorded in animals receiving excess fluoride, though changes revealed inconsistent pattern. Radiographic changes in long bones in fluoride exposed rabbits included widening of metaphysis, thinning of cortical region, and a variety of osteopenic changes like osteoporosis and osteomalacia that were more prominent in animals receiving 200 ppm or more than 200 ppm fluoride in drinking water. Important changes in histomorphology of growth plate in long bones recorded in excess fluoride (> 100 ppm) exposed rabbits included irregular thickening of epiphyseal growth plate with haphazard orientation of chondrocytes forming nodular protrusion into metaphysis. Fluoride exposure induced both osteogenesis and osteoporosis to a degree varying with dose of fluoride exposure.

The use of circular and hybrid external skeletal fixation systems to repair open tibial fractures in large ruminants: a report of six clinical cases

A prospective clinical study consisting of six bovines (200-300 kg body weight) undergoing open tibial fractures was carried out, to evaluate the use of circular and hybrid external skeletal fixation (ESF) systems for open tibial fracture repair in large ruminants. The ESF systems consisting of 4 full rings (n = 2), 8 half-rings (n = 1), 2 full rings with 2 sidebars (n = 2) or 2 full rings with 4 sidebars (n = 1) were used to treat open tibial fractures. The healing progress of the animals was evaluated based on different clinical and radiographic examinations. The level of fracture reduction, alignment, and fixation ranged between satisfactory to adequate in all the animals. The fixators were well tolerated and maintained by the animals till the complete repair of the fracture. Adequate fracture healing with satisfactory functional recovery was observed in all the animals in about 3-4 months. The different designs of ESFs were found to provide adequate stability in open tibial fractures in animals weighing 200-300 kg. However, the fixators need to be evaluated in numerous clinical cases to establish their suitability in routine clinical settings.

Decellularized xenogenic bone graft for repair of segmental bone defect in rabbits

Background

Bone grafting is a preferred treatment option for the healing of large diaphyseal bone defects and is useful in the management of nonunion, delayed union, and tumor resection.

Aims

To investigate a decellularization protocol of bovine cancellous bone for xenogenic implantation in radial bone defects in rabbits.

Methods

Bovine bone scaffolds fabricated with various decellularization protocols viz phosphate buffer saline (PBS), 1% sodium dodecyl sulfate (SDS), and rapid freeze and thaw technique. The manufactured scaffolds were characterized by biomechanical testing, histological staining, and scanning electron microscopy. A 10 mm rabbit radius bone defect was repaired with autograft and SDS treated and rapid freeze and thaw in groups A, B, and C respectively. Healing was evaluated by radiography and histopathology at 0, 30, 60, and 90 days. The grafts were also checked for host tissue reaction and incorporation into the defect.

Results

The freeze and thaw group showed complete elimination of all cellular nuclei, regular arrangement of collagen fiber, and no significant difference in tensile strength compared to 1% SDS treated and native groups. The in vivo radiographic and histopathological study showed that the rapid freeze and thaw group had complete bridging of the bone gap defect with new bone formation and they were immunologically less reactive compared to group B.

Conclusion

The in vitro and in vivo evaluation of the grafts suggested that freeze and thaw technique was most superior to all other techniques for effective decellularization and augmentation of bone healing with better integration of the graft into the host.

Biomechanical properties of a novel locking compression plate to stabilize oblique tibial osteotomies in buffaloes

OBJECTIVE

Quantitation of mechanical properties of a novel locking compression plate (LCP) for bovine tibia.

STUDY DESIGN

Prospective in vitro study.

SAMPLE POPULATION

Adult Murrah buffalo (250-350 kg) tibiae.

METHODS

Forty tibiae were randomly assigned to five treatment groups (n = 8/group): intact bone and bone constructs with a standard nonlocking plate, single LCP, double LCP, and novel LCP. During implant application, a mid-diaphyseal, oblique osteotomy was performed in all constructs, which were subsequently tested in axial compression (n = 4 each) or three-point craniocaudal bending (n = 4 each). Novel LCP alone (n = 4) was tested only in bending. Stiffness, yield load, ultimate failure load, and bending moment were determined from the load deformation curves and compared among different treatment groups (P < .05).

RESULTS

Under compression, yield load of the novel LCP (24.07 ± 3.45 kN) was greater than that of the nonlocking plate (11.10 ± 2.46 kN) and the single LCP (18.01 ± 2.07 kN) but less than that of the double LCP (30.61 ± 1.95 kN), and ultimate failure load of the novel LCP (25.85 ± 4.32 kN) was greater than that of the nonlocking plate (13.18 ± 2.91 kN) but similar to that of the single LCP (21.17 ± 2.33 kN) and the double LCP (32.40 ± 1.46 kN). Bending moment, yield load, and ultimate failure load of the novel LCP were 565.37 ± 79.30 Nm, 7.90 ± 1.14 kN, 9.83 ± 1.38 kN, respectively, which were greater than those of the nonlocking plate and the single LCP but comparable to those of the double LCP.

CONCLUSION

The novel LCP developed for bovine tibia was mechanically superior to the standard nonlocking plate or the single LCP and comparable to the double LCP.

CLINICAL SIGNIFICANCE

The novel LCP may provide rigid fixation of tibial diaphyseal fractures in buffaloes and cattle weighing 250 to 350 kg.

Allogeneic mesenchymal stem cells and growth factors in gel scaffold repair osteochondral defect in rabbit

Aim: An attempt was made to improve osteochondral healing with allogeneic mesenchymal stem cells (MSCs) along with certain growth factors. Materials & methods: Induced knee osteochondral defects were filled as: phosphate buffer saline (group A); MSCs in collagen gel (group B); group B plus insulin like growth factor-1 (group C); group C plus transforming growth factor β-1 (group D). Results: Gross and scanning electron microscopy showed superior morphology and surface architecture of the healed tissue in groups D and C. Histologically, group D revealed hyaline cartilage characteristic features followed in order by group C and group B. In all treatment groups, chondrogenic matrix, collagen II2B (col II 2B) and aggrecan were secreted. Conclusion: Combined use of MSCs and growth factors could accelerate osteochondral healing.

Mesenchymal stem cells with IGF-1 and TGF- β1 in laminin gel for osteochondral defects in rabbits

OBJECTIVE

Healing of articular cartilage is still a challenge due to its limited potential to regenerate. In the present study, we evaluated allogenic bone marrow mesenchymal stem cells (BM-MSCs) alone or in combination with growth factors, insulin-like growth factor-1 (IGF-1) and transforming growth factor-β1 (TGF-β1) in laminin scaffolds for healing of osteochondral defects.

DESIGN

Osteochondral defects of 4mm (diameter) x 5mm (depth) were induced in the rabbit knee joints and treated with phosphate-buffered saline (PBS; control), BM-MSCs, BM-MSCs in laminin, BM-MSCs in laminin with IGF-1, or BM-MSCs in laminin with IGF-1 and TGF-β1 in 10 animals each. Gross, radiographic, scanning electron microscopic (SEM) and histologic examinations besides chondrocyte-specific genes expression by quantitative real time qPCR were carried out at 8 and 12 weeks.

RESULTS

Gross and SEM examination revealed superior morphology and surface architecture of the healing site in animals that received MSCs with IGF-1 or IGF-1 and TGF-β1. The application of laminin composites containing MSCs with IGF-1 and TGF-β1 significantly enhanced hyaline cartilage formation with improved cellular arrangement, proteoglycan deposition, clear tidemark zone and subchondral bone formation. However, regenerated tissue in defects that received only MSCs had poor tidemark zone and proteoglycans deposition Aggrecan and Coll2 expression was significantly higher in case of MSCs with growth factors.

CONCLUSION

The treatment with BM-MSCs combined with IGF-1/TGF-β1 into laminin gel scaffold might enhance the restoration of hyaline cartilage in osteochondral defect.

Cartilage tissue engineering: Role of mesenchymal stem cells along with growth factors & scaffolds

Articular cartilage injury poses a major challenge for both the patient and orthopaedician. Articular cartilage defects once formed do not regenerate spontaneously, rather replaced by fibrocartilage which is weaker in mechanical competence than the normal hyaline cartilage. Mesenchymal stem cells (MSCs) along with different growth factors and scaffolds are currently incorporated in tissue engineering to overcome the deficiencies associated with currently available surgical methods and to facilitate cartilage healing. MSCs, being readily available with a potential to differentiate into chondrocytes which are enhanced by the application of different growth factors, are considered for effective repair of articular cartilage after injury. However, therapeutic application of MSCs and growth factors for cartilage repair remains in its infancy, with no comparative clinical study to that of the other surgical techniques. The present review covers the role of MSCs, growth factors and scaffolds for the repair of articular cartilage injury.

Evaluation of tissue-engineered bone constructs using rabbit fetal osteoblasts on acellular bovine cancellous bone matrix

Aim:

The aim of this study was to generate composite bone graft and investigate the rabbit fetal osteoblasts adhesion, proliferation and penetration on acellular matrices of cancellous bone.

Materials and Methods:

Acellular cancellous bone was prepared and developed as in the previous study with little modification. These matrices were decellularized by rapid freeze and thaw cycle. To remove the cell debris, they were then treated with hydrogen peroxide (3%) and ethanol to remove antigenic cellular and nuclear materials from the scaffold. Primary osteoblast cells were harvested from 20 to 22 days old rabbit fetal long and calvarial bone. These cells were cultured and characterized using a specific marker. The third passaged fetal osteoblast cells were then seeded on the scaffold and incubated for 14 days. The growth pattern of the cells was observed. Scanning electron microscope and hematoxylin and eosin staining were used to investigate cells proliferation.

Results:

The cells were found to be growing well on the surface of the scaffold and were also present in good numbers with the matrix filopodial extensions upto inside of the core of the tissue.

Conclusion:

Thus, a viable composite scaffold of bone could be developed which has a great potential in the field of bone tissue engineering.

Guinea pigs as an animal model for sciatic nerve injury

The overwhelming use of rat models in nerve regeneration studies is likely to induce skewness in treatment outcomes. To address the problem, this study was conducted in 8 adult guinea pigs of either sex to investigate the suitability of guinea pig as an alternative model for nerve regeneration studies. A crush injury was inflicted to the sciatic nerve of the left limb, which led to significant decrease in the pain perception and neurorecovery up to the 4^th weak. Lengthening of foot print and shortening of toe spread were observed in the paw after nerve injury. A 3.49 ± 0.35 fold increase in expression of neuropilin 1 (NRP1) gene and 2.09 ± 0.51 fold increase in neuropilin 2 (NRP2) gene were recorded 1 week after nerve injury as compared to the normal nerve. Ratios of gastrocnemius muscle weight and volume of the experimental limb to control limb showed more than 50% decrease on the 30^th day. Histopathologically, vacuolated appearance of the nerve was observed with presence of degenerated myelin debris in digestion chambers. Gastrocnemius muscle also showed degenerative changes. Scanning electron microscopy revealed loose and rough arrangement of connective tissue fibrils and presence of large spherical globules in crushed sciatic nerve. The findings suggest that guinea pigs could be used as an alternative animal model for nerve regeneration studies and might be preferred over rats due to their cooperative nature while recording different parameters.

Effect of IGF-1 and Uncultured Autologous Bone-Marrow-Derived Mononuclear Cells on Repair of Osteochondral Defect in Rabbits

OBJECTIVE

To investigate the utility of bone-marrow-derived mononuclear cells (BMNCs) and insulin like growth factor-1 (IGF-1) in articular cartilage repair.

DESIGN

An osteochondral defect of 3 mm diameter and 5 mm depth was created in patellar groove of the left knee joint in each of 36 New Zealand White rabbits. The defect was filled with RPMI-1640 medium in group A (control), autologous BMNCs in group B, and autologous BMNCs plus IGF-1 in group C (n = 12). Healing of the defect was assessed by gross, scanning electron microscopic, radiographic, and histological examinations up to 90 days.

RESULTS

Gross and scanning electron microscopic examination of the healing site revealed superior gross morphology and surface architecture of the healing tissue in the animals of group C as compared to other groups. Radiographically on day 90, the defect area was not distinguishable from the surrounding area in group C, but a small circular defect area was still evident in groups A and B. The regenerated tissue was mostly hyaline in group C and fibrocartilage in groups A and B. The cells were well organized and showed better deposition of proteoglycans in groups C and B than in group A.

CONCLUSIONS

It was concluded that implantation of bone-marrow-derived nucleated cells may facilitate the healing of osteochondral defects; however, the combination of BMNCs and IGF-1 induces faster and histologically better healing than the BMNCs alone.

Comparison of autogenic and allogenic bone marrow derived mesenchymal stem cells for repair of segmental bone defects in rabbits

Autogenic and allogenic bone marrow derived mesenchymal stem cells (BM-MSCs) were compared for repair of bone gap defect in rabbits. BM-MSCs were isolated from bone marrow aspirates and cultured in vitro for allogenic and autogenic transplantation. A 5mm segmental defect was created in mid-diaphysis of the radius bone. The defect was filled with hydroxyapatite alone, hydroxyapatite with autogeneic BM-MSCs and hydroxyapatite with allogenic BM-MSCs in groups A, B and C, respectively. On an average 3.45×10(6) cells were implanted at each defect site. Complete bridging of bone gap with newly formed bone was faster in both treatment groups as compared to control group. Histologically, increased osteogenesis, early and better reorganization of cancellous bone and more bone marrow formation were discernible in treatment groups as compared to control group. It was concluded that in vitro culture expanded allogenic and autogenic BM-MSCs induce similar, but faster and better healing as compared to control.

Evaluation of autologous bone marrow-derived nucleated cells for healing of full-thickness skin wounds in rabbits

The aim of the study was to evaluate the potential of autologous bone marrow-derived nucleated cells to enhance the rate of healing of full-thickness excisional skin wounds in rabbits. The study was conducted on 20 New Zealand white rabbits of either sex. Two, 2 x 2 cm full-thickness skin (thoracolumabar region) excisional wounds were created; one on each side of the dorsal midline in each animal. The wounds were randomly assigned to either injection of autologous bone marrow-derived nucleated cells into the wound margins (BI), or topical application of sterile saline solution (normal saline, NS), which served as control. The wound healing was assessed by evaluation of granulation tissue formation, wound contraction, epithelisation and histopathological and histochemical changes up to 28 days after creation of the wound. Granulation tissue appeared significantly faster in BI-treated wounds (3.22 +/- 0.22 days) than in NS-treated wounds (4.56 +/- 0.47 days). Better epithelisation was seen histologically in BI wounds than in NS-treated wounds. Wound contraction was significantly more in BI wounds when compared with NS wounds on 21 post-surgery. Histopathological examination of the healing tissue showed early disappearance of inflammatory reaction, significantly more neovascularisation, and more fibroplasias and early lay down and histological maturation of collagen in BI wounds than in control wounds. It was concluded that injection of autologous bone marrow-derived nucleated cells in the wound margins induced faster and better quality healing of excisional skin wounds in rabbits when compared with normal saline. The injection of autologous bone marrow-derived nucleated cells can be used to promote healing of large full-thickness skin wounds in rabbits.

Autologous bone marrow-derived cells for healing excisional dermal wounds of rabbits

The wound-healing potential of autologous bone marrow-derived nucleated cells was evaluated in full-thickness skin wounds in the thoracolumbar region of 20 clinically healthy rabbits. Three wounds of 2 x 2 cm, one on the left side and two right of the midline, were created on the dorsal lumbar region of each rabbit under xylazine-ketamine anaesthesia. The wounds of each animal were randomly assigned to one of three treatments: injection of autologous bone marrow-derived cells into wound margins (BI), topical application of bone marrow-derived cells over the wound surface (BT) or 5 per cent povidone iodine solution (PI) (control). Wounds were observed for 28 days for granulation tissue formation, wound contraction, histomorphological and histochemical evaluation, and time to complete healing. The mean (se) time to appearance of granulation tissue was significantly less in BI-treated wounds (3.22 [0.22] days) than the BT-treated (3.89 [0.40] days) and PI-treated (4.89 [0.47] days) groups. On days 14 and 21 after surgery, wound contraction was significantly (P<0.05) higher in BI-treated wounds (73.00 and 97.35 per cent) than in those treated with BT (58.75 and 84.87 per cent) and PI (54.84 and 84.60 per cent). Histomorphological findings showed an earlier disappearance of inflammatory reaction, better epithelialisation, significantly more neovascularisation, more fibroplasia and collagenation, and earlier histological maturation in BI- and BT-treated wounds than in control wounds.

Occurrence and pattern of long bone fractures in growing dogs with normal and osteopenic bones

A retrospective study was undertaken to record the occurrence and pattern of long bone fractures, and the efficacy of Intramedullary (IM) Steinmann pin fixing in growing dogs. All the records of growing dogs during a 10-year-period were screened to record the cause of trauma, the age and sex of the animal, the bone involved, the type and location of the fracture, the status of fixation, alignment, maintenance of fixation and fracture healing. The results were analysed and comparisons were made between growing dogs with normal and osteopenic bones. Among the 310 cases of fractures recorded, the bones were osteopenic in 91 cases (29%). Minor trauma was the principal cause of fracture in dogs with osteopenia (25%), and indigenous breeds were most commonly affected (38%). Fractures in dogs with osteopenic bones were most commonly recorded in the age group of 2-4 months (53%), whereas fractures in normal dogs were almost equally distributed between 2 and 8 months of age. Male dogs were affected significantly more often in both groups. In osteopenic bones, most fractures were recorded in the femur (56%), and they were distributed equally along the length of the bone. Whereas in normal bones, fractures were almost equally distributed in radius/ulna, femur and tibia, and were more often recorded at the middle and distal third of long bones. Oblique fractures were most common in both groups; however, comminuted fractures were more frequent in normal bones, whereas incomplete fractures were more common in osteopenic bones. Ninety-nine fracture cases treated with IM pinning (66 normal, 33 osteopenic) were evaluated for the status of fracture reduction and healing. In a majority of the cases (61%) with osteopenic bones, the diameter of the pin was relatively smaller than the diameter of the medullary cavity (<70-75%), whereas in 68% of the cases in normal bones the pin diameter was optimum. The status of fracture fixing was satisfactory to good in significantly more osteonormal (59%) than osteopenic dogs (42%). Fracture healing, however, was satisfactory in significantly more cases with osteopenic than normal bones. The appearance of callus was relatively early and the amount of bridging callus was relatively large in greater number of osteopenic bone fractures. Mal-union and non-union were recorded more often in osteopenic cases than in normal cases. However, the incidence of bone shortening and osteomyelitis was significantly higher in normal bones than in osteopenic bones.

Management of fractures near the carpal joint of two calves by transarticular fixation with a circular external fixator

A four-ring circular external skeletal fixation device was evaluated for transcarpal fixation of compound fractures in two calves. Case 1 was an eight-month-old female Holstein-Friesian x indigenous breed calf weighing 72 kg, which had a Salter-Harris type II fracture at the distal metaphysis of the right radius/ulna with an open contaminated wound on the medial aspect of the carpus. Case 2 was an 18-month-old crossbred Haryana heifer weighing 105 kg, which had a comminuted fracture at the proximal end of its left metacarpus with severe soft tissue trauma and an open wound on the medial aspect. In both cases, the fractures were repaired with four-ring circular fixators by fixing the proximal two rings in the distal radius/ulna and the distal two rings in the metacarpus. Postoperatively, both calves were treated with analgesic and anti-inflammatory drugs and antibiotic, and the pin-bone interfaces and the open wound were cleaned regularly with povidone-iodine solution. In both animals weight bearing was good to excellent in the immediate postoperative period. The fixator was well maintained and tolerated by the animals until the fractures healed after 45 to 60 days. The movement of the carpal joint was slightly affected when the fixator was removed on day 60, but a follow-up examination after one year showed that both calves had normal functional usage of the limbs.

Comparison of two doses of ropivacaine for lumbosacral epidural analgesia in buffalo calves (Bubalus bubalis )

Six male buffalo calves aged from six to eight months and weighing 100 to 120 kg were used to evaluate the efficacy and safety of caudal epidural analgesia produced by doses of 37.5 mg (5 ml) and 75 mg (10 ml) ropivacaine (0.75 per cent). The study was completed in two phases. In phase 1, all the animals were used twice to evaluate the analgesic and clinical effects of two doses of ropivacaine. In phase 2, the animals were divided into two groups of three to evaluate the effects of two doses of ropivacaine on some haemodynamic and acid-base parameters. Signs of analgesia, as evidenced by a loss of response to pinprick stimulation, were recorded only at the tail, perineum and hindlimbs of the animals given 5 ml ropivacaine, but they extended from the tail to the thorax (T9) in the animals given 10 ml ropivacaine. The duration of analgesia was five to six hours in the animals given 5 ml ropivacaine and seven to eight hours in the animals given 10 ml ropivacaine. Animals of both groups became recumbent, but the score for ataxia was higher in the animals given 10 ml ropivacaine. The respiratory rate decreased significantly (P<0.05) below the baseline in the animals given 10 ml ropivacaine, but the rectal temperature, heart rate, mean arterial pressure, central venous pressure and acid-base and electrolyte parameters did not change significantly in either group.

Clinicophysiological Effects of Spinally Administered Ketamine and Its Combination with Xylazine and Medetomidine in Healthy Goats

The study was conducted in 9 healthy adult goats of either sex, weighing 15-20 kg, to evaluate and compare the clinicophysiological effects of spinally administered ketamine alone and in combination with xylazine and medetomidine. Nine trials each of the three treatments were conducted randomly by injecting ketamine (2.5 mg/kg) (n = 9), ketamine and xylazine (2.5 mg/kg and 0.05 mg/kg) (n = 9) and ketamine and medetomidine (2.5 mg/kg and 10 microg/kg) (n = 9). The drugs were administered at the lumbosacral subarachnoid space under strict aseptic conditions. The treatments were evaluated on the basis of clinicophysiological, haematological, biochemical and haemodynamic observations. Ketamine produced mild to moderate analgesia of the hindquarters. Its combination with either xylazine or medetomidine produced complete analgesia of the hindquarters for 45-60 min. Ataxia was moderate in the ketamine group, whereas animals attained sternal recumbency in the combination groups. A moderate degree of sedation was recorded in the combination groups. Heart rate and respiratory rate depression in the combination groups and heart rate and respiratory rate stimulation in ketamine group were recorded. Haematological parameters decreased in all the groups. Increase in serum glucose, creatinine and urea nitrogen was recorded in all the groups. Serum electrolytes did not show any significant change. The results showed that the combination of ketamine with xylazine or medetomidine at these dose rates produced a comparable degrees of analgesia of hindquarters with transient and minimal cardiopulmonary side effects.

Effects of epidural ketamine-xylazine combination on the clinicophysiological and haematobiochemical parameters of uraemic and healthy goats

Xylazine-ketamine combination was evaluated for its efficacy and safety after epidural administration in uraemic and healthy goats. The combination (xylazine 0.025 mg/kg and ketamine 2.5 mg/kg) was administered to uraemic (n = 6) and healthy (n = 6) animals in the lumbosacral epidural space. The combination was evaluated in terms of clinical, physiological, haematological and biochemical parameters. The onset of analgesia was faster in healthy animals than in uraemic animals. Xylazine and ketamine produced complete analgesia of tail, perineum, inguinal and thigh regions in all animals of both groups. However, healthy animals showed longer duration of complete analgesia than did uraemic animals. Greater ataxia was recorded in healthy animals than in uraemic animals. The heart rate showed a significant decrease in both groups; however, respiratory rate and rectal temperature did not show any significant changes. Haemoglobin, packed cell volume and total leukocyte count decreased non-significantly in both groups. Total leukocyte count was significantly higher in uraemic animals. A significantly higher value of urea nitrogen and creatinine was recorded in uraemic animals. The blood electrolytes (Na+, K+ and Cl-) and blood gases (PO2 and PCO2) did not show any significant changes in both groups; however, base excess was significantly higher in uraemic animals. The effects produced by the combination on different systems were transient and values normal as the effect of the drugs wore off. The results suggest that the combination when used epidurally in uraemic goats produced effective and safe surgical analgesia.

Evaluation of two dynamic axial fixators for large ruminants

OBJECTIVES

To evaluate healing of a radial osteotomy repaired by application of dynamic axial fixation devices (DAF) in large ruminants.

STUDY DESIGN

In vivo study of bone healing after application of 2 DAF types. Model I had 2 sidebars, each with a central cylindrical cuff (internally threaded) with 2 detachable connecting rods telescoping within the cuff. Model II had 2 side bars with 2 moveable clamps with multiple holes.

SAMPLE POPULATION

Bull calves (n=8; aged, 1.5-2.0 years; weighing, 175-250 kg).

METHODS

A mid-diaphyseal radial osteotomy was repaired by use of a model I (n=4) or model II (n=4) DAF. Calves were monitored for weight bearing, stability of fixation, and radiographically for fracture reduction, alignment and healing at intervals for 6 months. Fixators were removed when there was radiographic evidence of healing.

RESULTS

Both the fixators were well tolerated with free movement of adjacent joints. Fragment fixation was maintained until healing in all but 1 model I calf where failure occurred within 7 days. Model II DAF provided more rigid fixation as indicated by early full weight bearing and fracture healing with less callus formation. Functional recovery of repaired limbs occurred within 60 days in surviving calves.

CONCLUSIONS

Both bilateral DAFs were easy to apply; however, the model II DAF provided better fixation.

CLINICAL RELEVANCE

The model II DAF made of low carbon steel was economical and may be useful for treating long bone fractures in large ruminants.

In Vitro Biomechanical Properties of Linear, Circular, and Hybrid External Skeletal Fixation Devices for Use in Large Ruminants

OBJECTIVE

To report the biomechanical properties of 3 external skeletal fixation (ESF) devices for use in large ruminants.

STUDY DESIGN

In vitro biomechanical testing of ESF constructs.

SAMPLE POPULATION

Adult buffalo (weighing, 250-350 kg) tibiae (n=27).

METHODS

ESF constructs (bilateral linear fixator [BLF], 4-ring circular external fixator [CEF], and hybrid fixator [HF]) were made using mild (low carbon) steel implants plated with nickel and cadaveric buffalo tibiae. After ESF application, a 1 cm mid-diaphyseal gap was created. Constructs were loaded to failure, on a materials testing machine, in axial compression (n=5/ESF type) and craniocaudal bending (n=3/ESF type). In addition, 3 CEF constructs were tested in intact tibiae under craniocaudal bending.

RESULT

In compression, HF was the strongest and most rigid construct; yield load was significantly higher for HF than for BLF or CEF. Under bending, both CEF and HF had similar strength and modulus of elasticity. Strength for BLF was higher than CEF and HF, whereas the reverse was true for modulus of elasticity.

CONCLUSIONS

ESF made from mild steel for use in large ruminants could withstand<or=300 kg load applied under compression and bending moment without any substantial adverse biomechanical effects on the constructs. HF was most rigid and strong under compression, whereas BLF was strongest in craniocaudal bending. Overall, HF seemed biomechanically the most suitable ESF device.

CLINICAL RELEVANCE

A hybrid ESF developed using mild steel is sufficiently strong and economical and may prove useful for fixation of long bone fractures in large ruminants (weighing<or=300 kg).

Xylazine, Ketamine and their Combination for Lumbar Epidural Analgesia in Water Buffalo Calves (Bubalus bubalis)

The study was conducted to evaluate the effects of xylazine individually (0.05 mg/kg), ketamine individually (2.5 mg/kg), and a combination of xylazine and ketamine (0.05 mg/kg and 2.5 mg/kg) after lumbar epidural administration in water buffalo calves. Fifteen non-descript, male water buffalo calves of 6-8 months of age weighing between 55 and 75 kg were randomly placed in three groups (groups A, B and C). The agents were administered at the first lumbar epidural space. Clinico-physiological parameters, such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen (BUN), creatinine, alanineamino transferase (ALT), sodium, potassium and chloride. The onset of analgesia (mean +/- SEM) was faster in group C (3.2 +/- 0.20 min) compared with that of group B (4.6 +/- 0.22 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in group C and mild in groups A and B. Mild to deep sedation was produced by groups A and C animals. Group B animals failed to produce sedation. Longer duration and greater depth of analgesia was produced in animals of group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, BUN, creatinine, and ALT increased in all the animals. However, total proteins and albumin decreased in the three groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible synergistic analgesic interaction between epidurally administered xylazine and ketamine, without causing any marked systemic effects in water buffalo calves.

Effects of xylazine, lignocaine and their combination for lumber epidural analgesia in water buffalo calves (Bubalus bubalis)

The study was conducted to evaluate the effects of xylazine alone (0.05 mg/kg), lignocaine alone (2.0 mg/kg) and a combination of xylazine and lignocaine (0.05 mg/kg and 2.0 mg/kg, respectively) after lumbar epidural administration in water buffalo calves. Fifteen nondescript, male water buffalo calves of 6-8 months of age and weighing between 55 and 75 kg were randomly placed in 3 groups (A, B and C). The agents were administered at the 1st lumbar epidural space. Clinico-physiological parameters such as analgesia, ataxia, sedation, salivation, heart rate, respiratory rate and rectal temperature were studied. Other haematological and biochemical parameters monitored were haemoglobin, packed cell volume, total leukocyte count, plasma glucose, cortisol, protein albumin, globulin, blood urea nitrogen, creatinine, ALT, sodium, potassium and chloride. The onset of analgesia was faster in group C (3.0 +/- 0.44 min) compared with that of group B (4.4 +/- 0.40 min) and group A (34.0 +/- 1.86 min). Analgesia of the thorax, flank, inguinal region, hind limbs, perineum and tail was complete in group C, but mild to moderate in groups A and B. Ataxia was severe in groups B and C and mild in group A. Mild to deep sedation were produced by groups A and C animals. Longer duration and greater depth of analgesia was produced in animals in group C. Heart rate, respiratory rate and rectal temperature decreased in groups A and C. The haematological parameters decreased in all the groups. The biochemical parameters like glucose, cortisol, blood urea nitrogen, creatinine, ALT increased in all the animals. However, total proteins and albumin decreased in the 3 groups. The plasma electrolytes sodium, potassium and chloride did not show any significant change. The results of this study indicated a possible additive analgesic interaction between epidurally administered xylazine and lignocaine, without causing any marked systemic effects in water buffalo calves.

Medetomidine with ketamine and bupivacaine for epidural analgesia in buffaloes

The efficacy of ketamine and bupivacaine in enhancing the epidural analgesia induced by medetomidine was evaluated in 10 buffalo calves utilized repeatedly after a gap of 10 days so that each drug combination was tested in 4 randomly selected animals. In group A, medetomidine (15 microg/kg), in group B ketamine (2.0 mg/kg), in group C bupivacaine (0.125 mg/kg), in group D medetomidine and ketamine (15 microg/kg and 2.0 mg/kg), and in group E medetomidine and bupivacaine (15 microg/kg and 0.125 mg/kg) was administered epidurally. Onset of analgesia was significantly earlier in animals of groups B and D compared to the animals of groups A, C and E. Medetomidine alone or in combination with ketamine/bupivacaine produced complete analgesia of the tail, perineum, inguinal region and upper parts of hind limbs. Ketamine produced a very short duration of complete analgesia at the tail and perineum. Bupivacaine alone produced only mild to moderate analgesia. Both ketamine and bupivacaine prolonged the duration of analgesia. Motor incoordination was mild to moderate in animals of all the groups, but animals remained standing throughout the period of observation. Animals of groups A, D and E showed mild to moderate sedation during the observation period. Ruminal movements decreased nonsignificantly in animals of groups A and E. Mild salivation was observed in animals of all the groups except group C. Significant decrease in heart rate (HR) was recorded after epidural administration of medetomidine or bupivacaine; however, ketamine caused short duration of tachycardia. The administration of ketamine with medetomidine caused lesser decrease in HR compared to medetomidine alone or in combination with bupivacaine. Significant fall in respiratory rate (RR) was recorded after epidural administration of medetomidine or bupivacaine alone, but an increase in RR was recorded after ketamine administration. The fall in RR was less pronounced in animals in which medetomidine was used with ketamine compared to the animals in which medetomidine was used alone or in combination with bupivacaine. Mean arterial pressure (MAP) decreased and central venous pressure (CVP) increased significantly after epidural administration of medetomidine in combination with ketamine or bupivacaine. The ECG changes included tall T wave, QS pattern, RS pattern and ST elevation and heart blocks at different intervals, which were more frequent and pronounced in animals given bupivacaine with medetomidine. It can be concluded that epidural administration of medetomidine can produce complete analgesia of the tail, perineum, inguinal region and upper hind limbs in buffaloes. However, significant depression of cardiovascular parameters was recorded. Administration of ketamine along with medetomidine resulted in significantly early onset and slightly longer duration of analgesia with lesser cardiopulmonary side-effects compared to medetomidine alone or medetomidine with bupivacaine. Addition of ketamine to medetomidine thus seems to be useful for producing epidural analgesia; however, addition of bupivacaine failed to provide any advantage over medetomidine alone.

The use of a circular external skeletal fixation device for the management of long bone osteotomies in large ruminants: an experimental study

The study was undertaken to evaluate the feasibility of a simple, inexpensive model of circular external fixator (CEF) for use in large ruminants. A simple model of CEF frames consisting of four full rings (13-19 cm diameter, 4 cm wide and 4 mm thick with 18-24 holes) connected by threaded rods (8 mm diameter, 10-15 cm long) and nuts was developed using mild (low carbon) steel and were nickel-plated. In the first phase of the study, three male cow calves were utilized to study the feasibility of application of the fixators in the metatarsus, tibia and radius, in reference of adaptation and tolerance by animals. In the second phase, the fixators were tested in osteotomized bones. Six bull calves of 1.5-2 years of age weighing about 200-250 kg were utilized for this purpose. After preparing the area for aseptic surgery, under xylazine (at 0.1 mg/kg, i.m.)-ketamine (i.v. till effect) general anaesthesia, the test bone (metatarsus, radius and tibia in two animals each) was approached through the medial surface and an osteotomy was created with a saw and chisel at the mid-diaphysis. The pre-constructed 4-ring CEF was mounted on the limb around the test bone in such a way that it formed a cylinder with the axis of the limb at the centre. Each ring was then fixed to the bone with a pair of beaded wires (316 SS) of 3.5 mm diameter. During the post-operative period, the animals were observed for any change in behaviour, tolerance of the fixators, the weight bearing on the test limb, the status of the fixator, and the level of reduction of the osteotomy, alignment and healing at different intervals. The fixation of CEF was easier in the metatarsus and radius than in the tibia. The inner ring diameters found adequate for metatarsus, radius and tibia were 13-15 cm, 15-17 cm and 17-19 cm, respectively. The fixators applied to different bones were well-tolerated, and the animals could lay down, stand and walk freely with the fixator without any problems. All the animals showed good weight bearing in the immediate post-operative period. Weight bearing, however, slightly reduced in the inflammatory period and showed improvement after about 4 weeks. Wire tract infection was seen in all the animals, which was more on proximal wire tracts on lateral aspect of limbs. Circular fixators were well-tolerated by all the animals, and there was no breaking/bending of connecting rods, slotted bolts or the rings at any stage of observation. Slight bowing of some wires was noticed in cases of tibia and radius (in phase II) and bending of some wires was noticed from first week in two animals one each in radius and tibia. Bone fragments were well maintained until healing occurred (appearance of bridging periosteal callus) at 60-70 days. The functional results were good in all but one case of tibia, where a mal-union was recorded. From this study, it can be concluded that CEF are well-tolerated by large ruminants and can be used to treat long bone fractures. The fixator assembly using mild steel is sufficiently strong to maintain fracture fixation and is inexpensive. The simple design of the CEF appears to be sufficient to treat simple diaphyseal fractures of the metatarsus and radius. Improvement in the technique of fixation and design-like coupling of linear and circular fixator components into hybrid constructs may help to provide greater rigidity in treating tibial and open long bone fractures.

Influence of Yohimbine and Atipamezole on Haemodynamics and ECG after Lumbosacral Subarachnoid Administration of Medetomidine in Goats

Effects of intravenous yohimbine and atipamezole on haemodynamics and electrocardiogram (ECG) were studied after lumbosacral subarachnoid administration of medetomidine in eight goats. All goats received lumbosacral subarachnoid medetomidine at a dosage of 0.01 mg/kg followed by yohimbine (0.25 mg/kg) or atipamezole (0.005 mg/kg) intravenously 45 min after administration of medetomidine, in a randomized crossover design, in right lateral recumbency keeping a gap of 1 week between each trial. Heart rate, respiratory rate, rectal temperature, mean arterial pressure (MAP), mean central venous pressure (MCVP) and ECG were determined. Goats were observed for sedation and urination. All goats showed sedation and depression after medetomidine administration became alert within 2-5 min after reversal. Bradycardia and bradypnoea were the consistent findings after medetomidine injection. Tachycardia and tachypnoea were recorded within 2-5 min after reversal in both groups. A decrease in MAP and an increase in MCVP were seen after medetomidine administration in both groups. Effects of yohimbine and atipamezole on the reversal of MAP and MCVP were more or less the same and statistically non-significant (P > 0.05) in all animals. The ECG changes were non-significant (P > 0.05) in both groups. It is concluded that in the given dose rates both yohimbine (0.25 mg/kg) and atipamezole (0.005 mg/kg) produced equal reversal of the sedation, CNS depression, cardiopulmonary and ECG changes induced by subarachnoid administration of medetomidine in goats indicating that most of the actions of medetomidine were mediated via activation of alpha2-adrenergic receptors.

Interaction Between Epidurally Administered Ketamine and Pethidine in Dogs

The present study was designed to test the hypothesis that a synergistic interaction could be recorded after epidural administration of ketamine-an N-methyl-D-aspartate (NMDA) antagonist and pethidine--an opioid agonist. Twelve adult mongrel dogs of either sex were randomly divided in three groups A, B and C of four animals each. Ketamine (5%) at 2.5 mg/kg and pethidine (3%) 2 mg/kg were injected at lumbosacral epidural space in animals of groups A and B, respectively. In animals of group C ketamine (2.5 mg/kg) and pethidine (2 mg/kg) were injected. Heart rate increased significantly up to 15 min in group A, whereas in groups B and C, the increase was non-significant for a period of 10 and 45 min, respectively. Respiration increased gradually up to 45-60 min in group A and for 15-20 min in group B. However, in animals of group C respiration fell below the baseline during the first 10-15 min and then returned near the baseline. Rectal temperature decreased only marginally in all the groups. Ketamine alone produced complete analgesia at tail and perineal region for a period of 5-10 min and then moderate analgesia for the next 20-30 min. Analgesia at the flank was moderate to complete between 5 and 15 min. In group B complete analgesia was only moderate at the tail and perineal region up to 30 min. In animals of group C, complete analgesia was observed only at perineal region for a very short period (5 min). Analgesia was not associated with sedation in any of the groups but animals of groups A and C showed signs of motor incoordination. Results of the study suggest rather antagonistic than synergistic interaction between epidurally administered ketamine and pethidine. Further studies are needed to confirm the antagonistic interaction between the two drugs.

Analgesic, sedative and haemodynamic effects of spinally administered romifidine in female goats

The present study was designed to evaluate the analgesic, sedative and haemodynamic effects of spinally administered romifidine in goats. Ten female healthy goats weighing 14-18 kg were randomly divided into two groups, I and II, of five animals each. Romifidine was administered spinally at rates of 50 and 75 microg/kg body weight in the animals of groups I and II, respectively, into the lumbosacral space. The treatments were compared based on their effects on analgesia, sedation, ataxia, heart rate, respiratory rate, rectal temperature, mean arterial pressure, central venous pressure, electrocardiogram and haemato-biochemical parameters. The objective parameters were analysed statistically using paired t-test and Duncan's multiple range test. Depth of analgesia was measured by recording the response to pin prick at different regions and was graded on a scale from 0 to 3. Moderate to complete analgesia was recorded at perineum and flank in both groups. Sedation was moderate in both groups. Ataxia was observed in all the animals but it was more pronounced in group II. Heart rate decreased significantly (P < 0.01) in both groups. A decrease in respiration rate was also recorded in both groups but it was more significant (P < 0.01) and for longer duration in group II as compared to group I. A slight increase in rectal temperature was also observed in both groups. Mean arterial pressure decreased and central venous pressure increased significantly (P < 0.01) in both groups but changes were more pronounced in group II. Electrocardiogram changes in group I included bradycardia, increased QT interval and increased or biphasic T wave but in animals of group II, in addition to these changes, occasional sinus dysrhythmia, increased PR interval and second-degree heart block were also recorded. Haemoglobin and packed cell volume decreased non-significantly in both groups. A significant (P < 0.01) increase in blood glucose and non-significant changes in plasma proteins, urea nitrogen and creatinine were recorded in both groups. The results of the study revealed that romifidine at the rate of 50 microg/kg could produce moderate to complete analgesia of perineum and flank after spinal administration into the lumbosacral space in goats. The analgesia could not be enhanced further by increasing the dose of romifidine up to 75 microg/kg, however, ataxia and cardiopulmonary and haemodynamic side-effects became more apparent.

Analgesic and cardiopulmonary effects of intrathecally administered romifidine or romifidine and ketamine in goats (Capra hircus)

The study was conducted to evaluate the effects of romifidine alone (50 microg/kg) and a combination of romifidine (50 microg/kg) and ketamine (2.5 mg/kg) after intrathecal administration in goats. Ten adult goats of either sex weighing between 15 and 20 kg were randomly placed in 2 groups (groups I and II). The agents were administered at the lumbosacral subarachnoid space. Clinico-physiological parameters such as analgesia, motor incoordination, sedation, salivation, heart rate, respiratory rate, arterial pressure, central venous pressure and rectal temperature were studied. Other haematobiochemical parameters monitored were packed cell volume, haemoglobin, plasma proteins, glucose, urea and creatinine. The onset of analgesia was faster in group II (35.5 +/- 6.25 s) compared to that of group I (5.2 +/- 0.54 min). Analgesia of the tail, perineum, hind limbs, flank and thorax was mild to moderate in group I, but complete analgesia of tail, perineum and hind limbs was recorded in group II. Motor incoordination was mild in group I and severe in group II. Significant reduction in heart rate (more pronounced in group I) and respiratory rate (more pronounced in group II), and a significant increase in central venous pressure were recorded in both groups. Mean arterial pressure was reduced in both groups, but more markedly in group I. Sedation, electrocardiogram, rectal temperature and haemato-biochemical parameters did not show significant differences between the 2 groups. The results of this study indicated a possible synergistic analgesic interaction between intrathecally administered romifidine and ketamine, without causing any marked systemic effects in goats.

Detomidine-diazepam-ketamine anaesthesia in buffalo (Bubalus bubalis) calves

Eight buffalo calves (8-12 months, 70-100 kg) were randomly assigned to two groups of four animals each. Animals of group I were given detomidine (100 micrograms/kg), whereas animals of group II received a mixture of detomidine (100 micrograms/kg), diazepam (100 micrograms/kg) and ketamine (3 mg/kg) (DDK) intravenously. Various clinical parameters, such as weak time, down time, pedal and pinprick reflexes, muscle relaxation and extent of sedation, as well as heart and respiratory rates and electrocardiograms were measured before (time 0) and 15, 30, 45, 60, 75 and 90 min after treatment. In all the animals of group II (DDK), the pedal reflex was completely abolished (score: 3.00 +/- 0.00) within 5 min, the pinprick response was either very weak or it was completely abolished at this interval. Muscle relaxation and sedation were excellent within 5 min of DDK administration. The depth of sedation and analgesia was maximum from 5 to 15 min postinjection. Detomidine alone, however, failed to produce appropriate depression of the pedal and pinprick reflexes, sedation was mild and muscle relaxation was inadequate. Heart rate showed a significant (P < 0.05) decrease in group I, but the decrease was non-significant in group II. A more pronounced increase in respiratory rate was observed in group I as compared to group II. Animals of both groups recovered within 90 min without any complication. Minimal changes in the cardiovascular system in the group given the DDK combination were an advantage over the group given detomidine. The results indicated that DDK combination is safe and suitable for 15 min of anaesthesia with excellent muscle relaxation and has only limited cardiorespiratory effects in buffaloes.

Fractures secondary to nutritional bone disease in dogs: a review of 38 cases

The pattern of bone fractures secondary to nutritional bone disease in 38 dogs was analysed using a radiographic survey. The majority of fractures were either caused by a fall (28.95%) or showed no history of direct trauma (31.58%). Mongrels were more commonly affected by pathological fractures, followed by Dobermanns and German Shepherds. Significantly more (P < 0.05) fractures were found in dogs aged less than 6 months (64.71%). The incidence of such fractures was significantly higher in males than in females (M:F = 2.70:1.00). General radiological signs included a generalized decrease in cortical density, thinning of cortices and widening of metaphyses/epiphyses in most of the animals. Fractures were found significantly more frequently (P < 0.01) in the femur (81.58%) than in any other bone. Of the different types of fracture, complete oblique and incomplete fractures were most common.

Effects of subarachnoid xylazine and medetomidine on haemodynamics and ECG in goats

The effects of subarachnoid administration of the alpha 2-agonists xylazine and medetomidine on haemodynamic parameters in six adult goats were evaluated. Xylazine (0.05 mg/kg body wt) or medetomidine (0.01 mg/kg body wt) was administrated in the lumbosacral subarachnoid space. Mean arterial blood pressure and central venous pressure and electrocardiograms were monitored up to 120 min post-injection. Xylazine and medetomidine produced significant and comparable decreases in mean arterial blood pressure in the post-injection period. However, mean central venous pressure increased during this period. The ECG changes produced by these drugs were bradycardia and increased PR and QT intervals. The study suggested that both alpha 2-agonists depress haemodynamic parameters and produce comparable effects after subarachnoid administration.