Changbaig Hyun

Comparison of the pathogenicity in three different Korean canine parvovirus 2 (CPV-2) isolates

Canine parvovirus type 2 (CPV-2) is a major pathogen inducing acute hemorrhagic gastroenteritis in dogs. Despite the identification of numerous CPV-2 variants (from CPV-2a to CPV-2c), the pathogenic differences among the CPV-2 variants in dogs have not been evaluated. The aim of this study was to compare the pathogenicity of CPV-2 variants (CPV-2a-I, CPV-2a-V and CPV-2b) isolated mainly from Korea. We evaluated the pathogenicity of three different CPV-2 variants, by performing clinical, hematological, serological and histopathological examinations after experimentally inoculating three types of CPV-2 variants into young puppies. We found that the overall pathogenicity of the CPV-2a variants (CPV-2a-I and 2a-V) was severer compared to the CPV-2b variant. In addition, there was no significant difference in pathogenicity between the two CPV-2a variants. Our findings indicate that there are differences in the pathogenicity of CPV-2 variants in dogs, which may be useful to understand the different pathobiology of the CPV-2 variants.

Ultrasonographic evaluation of renal dimension and resistive index in clinically healthy Korean domestic short-hair cats

Renal length, height, width, resistive index (RI), size of cortex, and medulla were determined by renal ultrasonography in 50 healthy Korean domestic short-hair cats. In the sagittal plane, the renal length was 3.83 ± 0.51 cm (mean ± SD) in the left kidney and 3.96 ± 0.48 cm in the right kidney, whereas the renal height was 2.42 ± 0.27 cm in the left kidney and 2.36 ± 0.28 cm in the right kidney. In the transverse plane, the renal height was 2.42 ± 0.28 cm in the left kidney and 2.38 ± 0.27 cm in the right kidney, whereas the renal width was: 2.65 ± 0.35 cm in the left kidney and 2.63 ± 0.31 cm in the right kidney. In the dorsal plane, the renal length was 3.84 ± 0.53 cm in the left kidney and 3.97 ± 0.54 cm in the right kidney, whereas the renal width was 2.65 ± 0.34 cm in the left kidney and 2.66 ± 0.33 cm in the right kidney. There were no significant differences (p > 0.05) among the same structure sizes measured in different planes. In the sagittal plane, the size of the renal cortex was 0.47 ± 0.08 cm in the left kidney and 0.47 ± 0.08 cm in the right kidney, whereas of the size of the renal medulla was 0.55 ± 0.30 cm in the left kidney and 0.50 ± 0.07 cm in the right kidney. RI evaluated by pulsed wave Doppler sonography was 0.52 ± 0.05 in the left kidney and 0.55 ± 0.05 in the right kidney. The actual renal dimensions determined by gross examination were not statistically different from those determined by ultrasonography. Furthermore the renal dimensions and RI were statistically correlated to the body weight of cats.

The optimal size and placement of transdermal electrodes are critical for the efficacy of a transcutaneous pacemaker in dogs.

Transcutaneous cardiac pacing (TCP) can be used in dogs with a high risk for bradyarrhythmias prior to anesthesia, either in an emergency room or intensive care unit setting. Furthermore, TCP can also be used on patients diagnosed with bradyarrhythmias that require temporary pacing at the induction of anesthesia for the implantation of a permanent pacemaker. Despite the importance of TCP in emergency medicine, no studies have evaluated the optimal size and placement of the transdermal electrodes crucial for the efficacy of TCP in dogs. This study evaluated four different sizes of electrodes (10.5, 20, 30 and 40 cm2), and four different anatomical sites (anterior-posterior, left-right, apex-base, modified left-right) in order to optimize the efficacy of TCP in dogs. Electrodes with a surface area of 20 cm2 and a modified left-right placement minimized the pacing current and involuntary skeletal muscular contraction (muscular twitching) and so achieved the most optimal effect of TCP in dogs.

The Cardiac Biomarker Sodium-Calcium Exchanger (NCX-1) Can Differentiate between Heart Failure and Renal Failure: A Comparative Study of NCX-1 Expression in Dogs with Chronic Mitral Valvular Insufficiency and Azotemia

BACKGROUND The sodium-calcium exchanger (NCX-1), an established cardiac biomarker, was postulated previously as differentiating between heart failure (HF) and renal failure (RF) in dogs. The effect of azotemia on NCX-1 expression has not been studied. HYPOTHESIS In contrast to other cardiac biomarkers (eg, N-terminal-proBNP), we hypothesized that the expression level of NCX-1 is not influenced by either azotemia or decreased renal clearance. ANIMALS Fifteen client-owned healthy control dogs, 14 dogs with chronic mitral valvular insufficiency (CMVI), classified based on severity of the disease by the established International Small Animal Cardiac Health Council classification system, and 15 dogs with RF, grouped according to the International Renal Interest Society stage classification. METHODS A comparative study of the expression levels of NCX-1, evaluated in peripheral blood samples from dogs with HF, RF, and healthy controls by quantitative PCR. RESULTS NCX-1 expression was significantly increased in moderate (2.99±0.61 [fold changes relative to normal group]) to severe (4.35±1.44) CMVI dogs (P<.01). In contrast, NCX-1 expression was not increased in the azotemic dogs. Furthermore, there was also no correlation between increased concentrations of creatinine and urea nitrogen in serum and NCX-1 expression in the RF group. CONCLUSIONS AND CLINICAL IMPORTANCE Azotemia likely does not affect NCX-1 expression.

Cardiopulmonary and anesthetic effects of the combination of butorphanol, midazolam and alfaxalone in Beagle dogs

OBJECTIVE To evaluate the physiological variables, arterial blood gas values, induction of anesthesia quality, and recovery quality using the combination of butorphanol, midazolam and alfaxalone in dogs. ANIMALS Ten healthy adult Beagle dogs weighing 8.3 ± 3.1 kg. METHODS Rectal temperature (T), pulse rate (PR), respiratory rate (f(R)), mean arterial pressure (MAP), and arterial blood gases were measured and recorded prior to intravenous (IV) administration of butorphanol, prior to administration of both midazolam and alfaxalone IV 10 minutes later, then every 5 minutes for 20 minutes. M-mode echocardiographic left ventricular (LV) indices were measured before and 5 minutes after administration of alfaxalone. Qualitative scores for induction of anesthesia and recovery were allocated, duration of anesthesia and recovery were calculated, and adverse events were recorded. RESULTS Scores for induction and recovery quality were excellent. No significant adverse events were observed. Mean ± SD time from induction to extubation and to standing (full recovery) was 29 ± 6 and 36 ± 8 minutes, respectively. There were statistically significant changes in PR, f(R) and MAP after drug administration. Transient hypercarbia developed after alfaxalone injection. The echocardiographic LV indices were reduced after alfaxalone injection, although those changes were not statistically significant. CONCLUSIONS AND CLINICAL RELEVANCE The combination of butorphanol, midazolam and alfaxalone provided excellent quality of induction of anesthesia and exerted minimal cardiopulmonary effects in healthy dogs.

Catheter-guided percutaneous heartworm removal using a nitinol basket in dogs with caval syndrome

Carval syndrome is a severe heartworm infection where the worms have migrated to the right atrium and vena cava; this condition is associated with a myriad of clinical signs. Several non-surgical and interventional methods are currently used for mechanical worm removal. However, the success rate and complications related to these methods are heavily dependent on methodology and retrieval devices used. In this study, we developed a catheter-guided heartworm removal method using a retrieval basket that can easily access pulmonary arteries and increase the number of worms removed per procedure. With this technique, we successfully treated four dogs with caval syndrome.

Prevalence of the exon 2 deletion of the COMMD1 gene in Australian Bedlington terriers

Inherited copper toxicosis in Bedlington terriers is a chronic progressive hepatic disease caused by an abnormal accumulation of copper due to genetic derangement in the biliary copper excretion pathway. In this study, we screened a group of Australian Bedlington terriers for a previously identified mutation, an exon 2 deletion in the COMMD1 gene. The DNA samples used in this study were collected from 149 Bedlington terriers (60 males and 89 females), aged between four weeks to 13 years from eight different pedigrees obtained over a period of three years. We found 60 dogs (40%) were homozygous wild type, 42 dogs (28%) were homozygous mutant, and 47 dogs (32%) were heterozygous for the deletion of exon 2 in the COMMD1 gene. Not only this reports the first large scale genetic screening of the known COMMD1 mutation in Bedlington terriers, but our results also indicate a high prevalence of the COMMD1 mutation in Bedlington terriers that might also be useful as a marker of copper toxicosis. Inherited copper toxicosis was first identified in Bedlington terrier in USA, in 1975 (Hardy et al. 1975) and has since been reported in other countries including Australia (Eriksson 1983; Robertson et al. 1983; Kelly et al. 1984). This disease is an inherited autosomal recessive disorder characterized by a progressive accumulation of copper, predominantly in the liver (Hardy 1984; Johnson et al. 1980). The main pathogenesis of the copper toxicosis in Bedlington terrier appears to be related to the reduced biliary excretion of stored copper resulting from a genetic derangement in copper metabolism (Hardy 1984; Hyun and Filippich 2004). A mutation resulting in the deletion of exon 2 in the COMMD1 (formerly known asMurr1) gene was found to be responsible for copper toxicosis in a subpopulation of Bedlington terriers (Van de Sluis et al. 2002)

Isolation, characterization and genetic analysis of canine GATA4 gene in a family of Doberman Pinschers with an atrial septal defect

GATA4 is expressed early in the developing heart where it plays a key role in regulating the expression of genes encoding myocardial contractile proteins. Gene mutations in the human GATA4 have been implicated in various congenital heart defects (CHD), including atrial septal defect (ASD). Although ASD is the third most common CHD in humans, it is generally rare in dogs and cats. There is also no obvious predilection for ASD in dogs and cats, based on sex or breed. However, among dogs, the incidence rate of ASD is relatively high in Samoyeds and Doberman Pinschers, where its inheritance and genetic aetiology are not well understood. In this study, we identified and investigated the genetic aetiology of an ASD affected family in a pure breed dog population. Although the GATA4 gene was screened, we did not find any mutations that would result in the alteration of the coding sequence and hence, the predicted GATA4 structure and function. Although the aetiology of ASD is multifactorial, our findings indicate that GATA4 may not be responsible for the ASD in the dogs used in this study. However, this does not eliminate GATA4 as a candidate for ASD in other dog breeds.

Genetic screening of the canine zinc finger protein multitype 2 (cZFPM2) gene in dogs with tetralogy of Fallot (TOF)

A recent genetic study in humans where the ZFPM2 gene was screened for mutations revealed a heterozygous mutation that was found to contribute to several sporadic cases of tetralogy of Fallot (TOF). We hypothesized that this would also hold true for a study group of dogs with TOF. We isolated the full-length cDNA of the canine ZFPM2 and aligned the deduced amino acid sequence against sequences from other species. Our analysis indicated that the canine ZFPM2 was phylogenetically much closer to the human ZFPM2 compared with the mouse or rat sequences. Further gene expression analysis also failed to identify differential gene expression between affected and unaffected dogs. We screened the cZFPM2 for mutations in a group of dogs with TOF but found no significant base changes in either the splice sites or the coding regions.

Percutaneous heartworm removal from dogs with severe heart worm (Dirofilaria immitis) infestation

Canine heart worm disease is often life-threatening due to its various complications, including right side heart failure, caval syndrome and pulmonary eosinophilic granulomatosis. Several preventive medications and melarsomine have been developed and they are very effective to control heartworm infestation. However, in a case of severe infestation, melarsomine therapy often results in an unfavorable outcome because of the severe immune reaction caused by rapid killing of the adult worm. Surgical removal and an interventional method using flexible alligator forceps have been well described in the literature. Despite the usefulness of mechanical removal using flexible alligator forceps, the methodology still needs to be upgraded for increasing the applicability for treating dogs with severe infestation. We describe herein a newly developed percutaneous removal method for heartworms and this was successfully applied to 4 dogs with severe heartworm infestation. The follow-up studies also showed favorable outcomes with no complications.