Biomechanical comparison of bone staple techniques for stabilizing tibial tuberosity fractures

This study compared the biomechanical properties of bone-stapling techniques with those of other fixation methods used for stabilizing tibial tuberosity fractures using 3-dimensionally (3D)-printed canine bone models. Twenty-eight 3D-printed bone models made from computed tomography scan files were used. Tibial tuberosity fractures were simulated using osteotomy. All samples were divided into 4 groups. Group 1 was stabilized with a pin and tension-band wire; group 2, with a pin and an 8 mm-wide bone staple; group 3, with 2 horizontally aligned pins and an 8 mm-wide bone staple; and group 4 with a 10 mm-wide bone staple. Tensile force was applied with vertical distraction until failure occurred. The load and displacement were recorded during the tests. The groups were compared based on the load required to cause displacements of 1, 2, and 3 mm. The maximum failure loads and modes were recorded. The loads at all displacements in group 4 were greater than those in groups 1, 2, and 3. The loads at 1, 2, and 3 mm displacements were similar in groups 1 and 3. There was no significant difference between groups 1 and 3. Groups 1 and 4 provided greater maximum failure loads than groups 2 and 3. Failure occurred because of tearing of the nylon rope, tibial fracture, wire breakage, pin bending, and fracture around the bone staple insertion. In conclusion, these results demonstrate that the bone-stapling technique is an acceptable alternative to tension-band wire fixation for the stabilization of tibial tuberosity fractures in canine bone models.

Expression of neurotrophic factors in injured spinal cord after transplantation of human-umbilical cord blood stem cells in rats

We induced percutaneous spinal cord injuries (SCI) using a balloon catheter in 45 rats and transplanted human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) at the injury site. Locomotor function was significantly improved in hUCB-MSCs transplanted groups. Quantitative ELISA of extract from entire injured spinal cord showed increased expression of brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin-3 (NT-3). Our results show that treatment of SCI with hUCB-MSCs can improve locomotor functions, and suggest that increased levels of BDNF, NGF and NT-3 in the injured spinal cord were the main therapeutic effect.

Quantitative measurement of influenza virus replication using consecutive bronchoalveolar lavage in the lower respiratory tract of a ferret model

The ferret is an established animal model of influenza virus infection. Although viral replication in the upper respiratory tract is usually measured with consecutively collected nasal washes, daily evaluation of viral replication in the lung is limited because a large numbers of ferrets need to be sacrificed at consecutive time points. To overcome this limitation, we performed a virus quantification assay using bronchoalveolar lavage (BAL) fluid. This non-invasive BAL technique allows consecutive quantification of virus replication in the lungs of living ferrets. Our method can be used for the longitudinal evaluation of virus tropism in the lower respiratory tract.

Improved rat spinal cord injury model using spinal cord compression by percutaneous method

Here, percutaneous spinal cord injury (SCI) methods using a balloon catheter in adult rats are described. A balloon catheter was inserted into the epidural space through the lumbosacral junction and then inflated between T9-T10 for 10min under fluoroscopic guidance. Animals were divided into three groups with respect to inflation volume: 20 microL (n = 18), 50 microL (n = 18) and control (Fogarty catheter inserted but not inflated; n = 10). Neurological assessments were then made based on BBB score, magnetic resonance imaging and histopathology. Both inflation volumes produced complete paralysis. Gradual recovery of motor function occurred when 20 microL was used, but not after 50 microL was applied. In the 50 microL group, all gray and white matter was lost from the center of the lesion. In addition, supramaximal damage was noted, which likely prevented spontaneous recovery. This percutaneous spinal cord compression injury model is simple, rapid with high reproducibility and the potential to serve as a useful tool for investigation of pathophysiology and possible protective treatments of SCI in vivo.

Evaluation of a canine small intestinal submucosal xenograft and polypropylene mesh as bioscaffolds in an abdominal full-thickness resection model of growing rats

We evaluated the biological scaffold properties of canine small intestinal submucosa (SIS) compared to a those of polypropylene mesh in growing rats with full-thickness abdominal defects. SIS is used to repair musculoskeletal tissue while promoting cell migration and supporting tissue regeneration. Polypropylene mesh is a non-resorbable synthetic material that can endure mechanical tension. Canine SIS was obtained from donor German shepherds, and its porous collagen fiber structure was identified using scanning electron microscopy (SEM). A 2.50-cm2 section of canine SIS (SIS group) or mesh (mesh group) was implanted in Sprague-Dawley rats. At 1, 2, 4, 12, and 24 weeks after surgery, the implants were histopathologically examined and tensile load was tested. One month after surgery, CD68+ macrophage numbers in the SIS group were increased, but the number of CD8+ T cells in this group declined more rapidly than that in rats treated with the mesh. In the SIS group, few adhesions and well-developed autologous abdominal muscle infiltration into the SIS collagen fibers were observed. No significant differences in the tensile load test results were found between the SIS and mesh groups at 24 weeks. Canine SIS may therefore be a suitable replacement for artificial biological scaffolds in small animals.

Percutaneous transplantation of human umbilical cord-derived mesenchymal stem cells in a dog suspected to have fibrocartilaginous embolic myelopathy

The use of human umbilical cord blood-derived mesenchymal stem cells for cell transplantation therapy holds great promise for repairing spinal cord injury. Here we report the first clinical trial transplantation of human umbilical cord (hUCB)-derived mesenchymal stem cells (MSCs) into the spinal cord of a dog suspected to have fibrocartilaginous embolic myelopathy (FCEM) and that experienced a loss of deep pain sensation. Locomotor functions improved following transplantation in a dog. Based on our findings, we suggest that transplantation of hUCB-derived MSCs will have beneficial therapeutic effects on FCEM patients lacking deep pain sensation.

Development of a novel vaccine against canine parvovirus infection with a clinical isolate of the type 2b strain

PURPOSE: In spite of an extensive vaccination program, parvoviral infections still pose a major threat to the health of dogs. MATERIALS AND METHODS: We isolated a novel canine parvovirus (CPV) strain from a dog with enteritis. Nucleotide and amino acid sequence analysis of the isolate showed that it is a novel type 2b CPV with asparagine at the 426th position and valine at the 555th position in VP2. To develop a vaccine against CPV infection, we passaged the isolate 4 times in A72 cells. RESULTS: The attenuated isolate conferred complete protection against lethal homologous CPV infection in dogs such that they did not develop any clinical symptoms, and their antibody titers against CPV were significantly high at 7-11 days post infection. CONCLUSION: These results suggest that the virus isolate obtained after passaging can be developed as a novel vaccine against paroviral infection.

Use of canine small intestinal submucosa allograft for treating perineal hernias in two dogs

Here, we describe two dogs in which canine small intestinal submucosa (SIS) was implanted as a biomaterial scaffold during perineal herniorrhaphy. Both dogs had developed severe muscle weakness, unilaterally herniated rectal protrusions, and heart problems with potential anesthetic risks. Areas affected by the perineal hernia (PH) located between the internal obturator and external anal sphincter muscles were reconstructed with naive canine SIS sheets. In 12 months, post-operative complications such as wound infections, sciatic paralysis, rectal prolapse, or recurrence of the hernia were not observed. Symptoms of defecatory tenesmus also improved. Neither case showed any signs of rejection or specific immune responses as determined by complete and differential cell counts. Our findings demonstrate that canine SIS can be used as a biomaterial scaffold for PH repair in dogs.

Neurochemical Profile Quantification of Regional Adult Mice Brain Using: ex vivo 1H High-Resolution Magic Angle Spinning NMR Spectroscopy / 의학물리

The purpose of this study is to quantitate regional neurochemical profile of regional normal adult mice brain and assess regional metabolic differences by using ex vivo 1H high-resolution magic angle spinning nuclear magnetic resonance spectroscopy (1H HR-MAS NMRS). The animals were matched in sex and age. The collected brain tissue included frontal cortex, temporal cortex, thalamus, and hippocampus. Quantitative 1D spectra were acquired on 40 samples with the CPMG pulse sequence (8 kHz spectral window, TR/TE = 5500/2.2 ms, NEX = 128, scan time: 17 min 20 sec). The mass of brain tissue and D2O+TSP solvent were 8~14 mg and 7~13 mg. A total of 16 metabolites were quantified as follow: Acet, NAA, NAAG, tCr, Cr, tCho, Cho, GPC + PC, mIns, Lac, GABA, Glu, Gln, Tau and Ala. As a results, Acet, Cho, NAA, NAAG and mIns were showed significantly different aspects on frontal cortex, hippocampus, temporal cortex and thalamus respectively. The present study demonstrated that absolute metabolite concentrations were significantly different among four brain regions of adult mice. Our finding might be helpful to investigate brain metabolism of neuro-disease in animal model.

Measurement and Assessment of Absolute Quantification from in Vitro Canine Brain Metabolites Using 500 MHz Proton Nuclear Magnetic Resonance Spectroscopy: Preliminary Results

The purpose of this study was to confirm the exactitude of in vitro nuclear magnetic resonance spectroscopy (NMRS) and to complement the defect of in vivo NMRS. It has been difficult to understand the metabolism of a cerebellum using in vivo NMRS owing to the generated inhomogeneity of magnetic fields (B0 and B1 field) by the complexity of the cerebellum structure. Thus, this study tried to more exactly analyze the metabolism of a canine cerebellum using the cell extraction and high resolution NMRS. In order to conduct the absolute metabolic quantification in a canine cerebellum, the spectrum of our phantom included in various brain metabolites (i.e., NAA, Cr, Cho, Ins, Lac, GABA, Glu, Gln, Tau and Ala) was obtained. The canine cerebellum tissue was extracted using the methanol-chloroform water extraction (M/C extraction) and one group was filtered and the other group was not under extract processing. Finally, NMRS of a phantom solution and two extract solution (90% D2O) was progressed using a 500MHz (11.4 T) NMR machine. Filtering a solution of the tissue extract increased the signal to noise ratio (SNR). The metabolic concentrations of a canine cerebellum were more close to rat's metabolic concentration than human's metabolic concentration. The present study demonstrates the absolute quantification technique in vitro high resolution NMRS with tissue extraction as the method to accurately measure metabolite concentration.

Evaluation of Antidepressant Drug Effect in a Depressive Animal Model by Proton MR Spectroscopy / 의학물리

In this study, we observed the alteration of choline signal intensity in hippocampus region of the depressive rat model induced by forced swimming test (FST). The purpose of this study was to evaluate the antidepressant efficacy in the depressive animal model using MR spectroscopy. Fourteen experimentally naive male Sprague-Dawley rats weighting 160~180 g were used as subjects. Drug injection group was exposed to the FST except for control group. The drugs were administered subcutaneously (SC) in a volume equivalent to 2 ml/kg. And three injections were administered 23, 5, and 1 h before beginning the given test. 1H MR spectra were obtained with use of a point resolved spectroscopy (PRESS) localization sequence performed according to the following parameters: repetition time, 2500 ms; echo time, 144 ms; 512 average; 2048 complex data points; voxel dimensions, 1.5x2.5x2.5 mm3; acquisition time, 25 min. There were no differences in NAA/Cr and Cho/Cr ratio between the right and the left hippocampus both normal control rats and antidepressant-injected rats. Also, no differences were observed in NAA/Cr and Cho/Cr ratio between the normal control rats and the antidepressant-injected rats both the right and the left hippocampus. In this study, we found the recovery of choline signals in the depressive animal model similar to normal control groups as injecting desipramine-HCl which was antidepressant causing anti-immobility effects. Thus, we demonstrated that MR spectroscopy was able to aid in evaluating the antidepressant effect of desipramine-HCl.

Assessment on Gastrointestinal Transit Movement of Capsule Endoscopy in Beagle Dogs / 의학물리

The object of this study is to measure the transit time and passage rate of capsule endoscopy (CE) in the gastrointestinal tract in medium sized beagle dogs (7~13 kg). Animals were divided into four groups: only capsule (group 1, n=10), capsule+water (group 2, n=10), mettoclopramide+capsule (group 3, n=10), metoclopramide +capsule+water (group 4, n=10). The capsule transit times through the stomach and small bowel were evaluated by radiography findings. Gastric transit time (GTT), small intestinal transit time (SITT) and complete passage rate were measured in four groups. GTT's for each group were as follows; 45+/-20 min (group 1), 117+/-35 min (group 2), 150+/-40 min (group 3), and 154+/-65 min (group 4), while SITT's were 75+/-20 min (group 1), 195+/-55 min (group 2), 70+/-15 min (group 3), and 76+/-15 min (group 4). The complete passage rates were 20% (group 1), 40% (group 2), 20% (group 3), 50% (group 4). In all groups, if CE could pass through the pylorus, it passed all small intestinal tracts within 8 hours (battery life). Administration of water helped CE to pass pylori, except in case of metoclopramide administration. These results indicate that CE could be an useful tool for examining gastrointestinal diseases in the veterinary medicine.

Magnetic resonance imaging appearance of epidural hematoma in dog

Induction of castration by immunization of male dogs with recombinant gonadotropin-releasing hormone (GnRH)-canine distemper virus (CDV) T helper cell epitope p35

Immunocastration is a considerable alternative to a surgical castration method especially in male animal species for alleviating unwanted male behaviors and characteristics. Induction of high titer of antibody specific for gonadotropin-releasing hormone (GnRH) correlates with the regression of testes. Fusion proteins composed of canine GnRH and T helper (Th) cell epitope p35 originated from canine distemper virus (CDV) F protein and goat rotavirus VP6 protein were produced in E. coli. When these fusion proteins were injected to male dogs which were previously immunized with CDV vaccine, the fusion protein of GnRH-CDV Th cell epitope p35 induced much higher antibody than that of GnRH-rotavirus VP6 protein or GnRH alone. The degeneration of spermatogenesis was also verified in the male dogs immunized with the fusion protein of GnRH-CDV Th cell epitope p35. These results indicate that canine GnRH conjugated to CDV Th cell epitope p35 acted as a strong immunogen and the antibody to GnRH specifically neutralized GnRH in the testes. This study also implies a potential application of GnRH-based vaccines for immunocastration of male pets.