Hee-Myung Park

A comparison of autologous and allogenic bone marrow-derived mesenchymal stem cell transplantation in canine spinal cord injury

The purpose of this study is to compare the therapeutic effects between autologous and allogenic bone-marrow-derived mesenchymal stem cell (MSC) transplantation in experimentally-induced spinal cord injury (SCI) of dogs. Thirty adult Beagle dogs (control group=10, autologous group=10, and allogenic group=10) were used in this study. Prelabeled MSCs were intrathecally transplanted through the lumbar spinal cord into the injured lesion at a density of 1 x 10(7) cells 7 days after SCI. Neurological signs of dogs in both autologous and allogenic groups were improved in their pelvic limbs after SCI compared with those in control group. Both autologous and allogenic groups showed significantly higher the Olby scores than control group (p<0.05). This finding was consistent with results of MRI and histopathological examination in both groups. Immunofluorescence analysis revealed that prelabeled autologous and allogenic MSCs were detected in the injured lesions both at 1 and 4 weeks after transplantation. However, the distribution ratio of MSCs on the injured lesion in allogenic group was significantly decreased at 4 weeks after transplantation relatively to at 1 week after transplantation. The mRNA expression for neurotrophic factors in both allogenic and autologous groups was significantly higher than that in control groups (p<0.05). Even though autologous MSC transplantation showed more beneficial effect than that of allogenic MSC transplantation, transplantation of allogenic MSCs also improved functional recovery following SCI. This study demonstrates that both autologous and allogenic MSC transplantation could be clinically useful therapeutic approaches for treating SCI.

Analysis of complete genome sequences of swine hepatitis E virus and possible risk factors for transmission of HEV to humans in Korea.

The hepatitis E virus (HEV) is an emerging zoonotic agent, for which pigs are the most important reservoir. Complete genome sequences of two swine HEV strains, designated swKOR‐1 and swKOR‐2, were determined via RT‐PCR and RACE‐PCR. The strains contained genomes composed of 7,222‐ and 7,221‐bp excluding the poly(A) tails, respectively. The swKOR‐1 and swKOR‐2 strains were classified into subtype 3a of genotype 3 via phylogenetic analysis. These strains formed a distinctive cluster in the phylogenetic tree with human and swine HEVs isolated in the USA and human HEVs isolated in Japan. Anti‐HEV antibodies were identified via ELISA in 8 of 99 (8.1%) cats, whereas, among 115 cattle and 213 dogs, no HEV‐specific antibodies were detected. The conserved RNA‐dependent RNA polymerase (RdRp) gene of HEV could be detected via RT‐PCR in 8.7% of raw oysters collected from coastal regions in Korea. The HEV RNAs detected in oysters were identified as belonging to subtype 3a. The HEV RNAs in oysters most closely resembled that of the swKOR‐2 strain. They also showed a close genetic relationship with the swKOR‐1 strain and the swine and human HEVs isolated in the USA. This is the first report describing the detection in oysters of HEV that may have originated from genotype 3 swine HEV in Korea. Pigs and cats infected with HEV, as well as oysters contaminated with HEV, are potential risk factors for HEV transmission to humans. J. Med. Virol. 82:583–591, 2010.

Prevalence of genes for enterotoxins, toxic shock syndrome toxin 1 and exfoliative toxin among clinical isolates of Staphylococcus pseudintermedius from canine origin.

A total of 74 Staphylococcus pseudintermedius strains were isolated from the 99 clinical cases of canine pyoderma or chronic otitis in our veterinary teaching hospital during May 2006-February 2008. In this study, we examined the genetic distribution of staphylococcal pyogenic toxins such as staphylococcal enterotoxins A (sea), B (seb), C (sec), D (sed), E (see), and toxic shock syndrome toxin 1 (tst) as well as the previously characterized S. intermedius exfoliative toxin (siet) among those isolates. The polymerase chain reaction analyses with the toxin gene-specific primers revealed that 18 (24.3%) of 74 S. pseudintermedius isolates carried the sec genes, but none of the sea, seb, sed, see and tst genes. Further DNA sequencing analysis of the amplified sec genes revealed that they all belonged to the canine type C staphylococcal enterotoxin (SEC(canine) ) whose superantigenic activity has been demonstrated. In addition to the sec(canine) genes, our polymerase chain reaction results showed that all the 74 isolates carried the siet gene. Since both SEC(canine) and SIET toxins are known to be biologically active, it would be interesting to investigate how those toxins are involved in the pathogenesis of the canine diseases by S. pseudintermedius such as pyoderma or chronic otitis.

Curative effect of autologous platelet-rich plasma on a large cutaneous lesion in a dog.

A dorsal tail mass (1 x 1.2 cm) was observed on a 10-year-old castrated male, Shih-tzu dog. A biopsy of the mass was performed and diagnosed histopathologically as a follicular cyst. A necrotic lesion (2.5 x 3 cm) developed at the biopsy site 1 week after sampling and failed to respond to 2 weeks of normal saline cleansing and systemic antibiotic administration. Autologous platelet-rich plasma was applied to the lesion which gradually improved over a 4-week period possibly by a contribution to the secretion of growth hormone, which can accelerate tissue regeneration. This case report suggests that autologous PRP may be beneficial in the management of large skin defects or in delayed wound healing.

Severe canine influenza in dogs correlates with hyperchemokinemia and high viral load

Canine influenza virus (CIV) is an emerging pathogen that causes acute respiratory disease in dogs. To better understand the mechanism(s) responsible for the virulence of the virus, we conducted immunological, virological, clinical, and histopathological analyses in CIV-infected dogs. CIV replicated efficiently in the respiratory system of dogs and caused severe respiratory disease. Notably, the infection induced the marked elevation and sustained expression of chemokines that resulted in severe bronchointerstitial pneumonia with extensive neutrophil infiltration. In clinicopathological findings, CIV infection resulted in regenerative anemia, perhaps due to pulmonary hemorrhage. The observations indicate that active replication of CIV in the canine respiratory system results in intense inflammatory responses central to the pathogenesis of H3N2 CIV.

Prevalence of feline herpesvirus 1, feline calicivirus and Chlamydophila felis in clinically normal cats at a Korean animal shelter

The prevalence of feline herpesvirus-1 (FHV-1), feline calicivirus (FCV), and Chlamydophila (C.) felis was studied in cats of an animal shelter in Korea. Total 78 cats without ocular and upper respiratory tract disease were examined. Specimens were obtained from ocular conjunctiva and oropharynx. Using multiplex polymerase chain reaction (PCR) and reverse transcription PCR, three pathogens were simultaneously detected. In examined 78 cats, 49 (63%) cats were positive for FHV-1. However, all specimens were negative for C. felis and FCV. In conclusion, many cats recovered from FHV-1 infection remain subclinical carriers in shelter environment.

Canine model of ischemic stroke with permanent middle cerebral artery occlusion: clinical and histopathological findings

The aim of the present study was to assess the clinical and histopathological findings in a canine model of ischemic stroke. Cerebral ischemic stroke was induced by middle cerebral artery occlusion in four healthy beagle dogs using silicone plugs. They showed neurological signs of forebrain dysfunction such as reduced responsiveness, head turning, circling, postural reaction deficits, perceptual deficits, and hemianopsia. These signs gradually regressed within 4 weeks without therapy. On magnetic resonance imaging, T2 hyperintensity and T1 hypointensity were found in the cerebral cortex and basal ganglia. These lesions were well-defined and sharply demarcated from adjacent brain parenchyma with a homogenous appearance. No abnormalities of the cerebrospinal fluid were observed. At necropsy, atrophic and necrotic lesions were observed in the cerebral cortex. The cerebral cortex, basal ganglia, and thalamus were partially unstained with triphenyl-tetrazolium chloride. Histopathologically, typical features of infarction were identified in cortical and thalamic lesions. This study demonstrates that our canine model resembles the conditions of real stroke patients.

Detection of cerebral metabolites in a canine model of ischemic stroke using 1H magnetic resonance spectroscopy.

Proton magnetic resonance spectroscopy ((1)H MRS) provides in vivo biochemical information on tissue metabolites. The purpose of this study was to investigate the serial metabolic changes of (1)H MRS in the cerebrum of ischemic dogs. An ischemic stroke was induced in five health laboratory beagle dogs by permanent middle cerebral artery occlusion using a silicone plug. (1)H MRS was serially performed three times with a 1.5-T MR system: before, three days after and 10days after the stroke. Immunohistochemical staining was performed to determine the expression of neuronal nuclei (NeuN) and glial fibrillary acidic protein (GFAP) at both the ipsilateral and contralateral cerebral cortex. Reduced levels of N-acetyl-asparate (p<0.05), choline (Cho), creatine (Cr) and myo-inositol (mI), and a marked increase in the lactate (Lac) level (p<0.01) were found at three days after the stroke. At 10days after the stroke, the levels of Lac significantly increased (p<0.01); however, the other metabolites were partially elevated. The changes of Cr, Cho and mI were not statistically significant (p>0.05) when the before and after stroke values were compared. There was a significant loss of NeuN and GFAP immunoreactivity at the ischemic core. (1)H MRS may be to a useful diagnostic tool for the evaluation of ischemic stroke in dogs.

Sensitization rates of causative allergens for dogs with atopic dermatitis: detection of canine allergen-specific IgE.

Allergen-specific IgE serology tests became commercially available in the 1980s. Since then these tests have been widely used to diagnose and treat allergic skin diseases. However, the relationship between a positive reaction and disease occurrence has been controversial. The purpose of this study was to evaluate allergens using a serologic allergy test in dogs with atopic dermatitis (AD). Dogs clinically diagnosed with AD (n=101) were tested using an allergen-specific IgE immunoassay. Among the total 92 environmental and food allergens, house dust and house dust mites were the most common. Several allergens including airborne pollens and molds produced positive reactions, and which was considered increasing allergens relating to the climate changes. The presence of antibodies against staphylococci and Malassezia in cases of canine AD was warranted in this study. Additionally, strong (chicken, turkey, brown rice, brewers yeast, and soybean) and weakly (rabbit, vension, duck, and tuna) positive reactions to food allergens could be used for avoidance and limited-allergen trials.

DNA Detection and Genotypic Identification of Potentially Human-Pathogenic Microsporidia from Asymptomatic Pet Parrots in South Korea as a Risk Factor for Zoonotic Emergence

ABSTRACT We detected and identified genotypes of human-pathogenic microsporidia in fecal samples from 51 asymptomatic captive-bred pet parrots in South Korea. Microsporidia were identified in 8 samples (15.7%); 7 parrots tested positive for Encephalitozoon hellem, and 1 parrot tested positive for both E. hellem and Encephalitozoon cuniculi. In genotypic identifications, E. hellem was present in genotypes 1A and 2B and E. cuniculi was present in genotype II. Pet parrots might be a source of human microsporidian infection.