Injectable Poloxamer Hydrogel Formulations for Intratympanic Delivery of Dexamethasone

Background@#In this study, we prepared and evaluated an injectable poloxamer (P407) hydrogel formulation for intratympanic (IT) delivery of dexamethasone (DEX). @*Methods@#DEX-loaded P407 hydrogels were characterized in terms of thermogelation, drug loading capacities, particle size, and drug release. The in vivo toxicity and drug absorption of the DEX-loaded P407 formulation after IT injection were evaluated using an animal model by performing histopathological analysis and drug concentration measurements. @*Results@#The P407 hydrogel effectively solubilized hydrophobic DEX and demonstrated a sustained release compared to the hydrophilic DEX formulation. The in vivo study showed that the hydrogel formulation delivered considerable drug concentrations to the inner ear and displayed a favorable safety profile without apparent cytotoxicity or inflammation. @*Conclusion@#P407 hydrogel can be useful as an injectable inner ear delivery formulation for hydrophobic drugs due to their biocompatibility, drug-solubilizing capacity, thermogelation, and controlled release.

Full-length ORF2 sequence-based genetic and phylogenetic characterization of Korean feline caliciviruses

Feline calicivirus (FCV) is a highly infectious pathogen in cats and widely distributed worldwide with high genetic variation. Full-length open reading frame 2 of 5 from recently isolated Korean FCV isolates were sequenced and compared with those of global isolates. The results of phylogenetic analysis supported dividing global FCV isolates into two genogroups (type I and II) and demonstrated the presence of genogroup II in Korea, indicating their geographic spread in East Asia. High sequence variations in region E of the FCV isolates emphasizes that a novel vaccine needs to be developed to induce protective immunity against various FCV strains.

Full-length ORF2 sequence-based genetic and phylogenetic characterization of Korean feline caliciviruses

Feline calicivirus (FCV) is a highly infectious pathogen in cats and widely distributed worldwide with high genetic variation. Full-length open reading frame 2 of 5 from recently isolated Korean FCV isolates were sequenced and compared with those of global isolates. The results of phylogenetic analysis supported dividing global FCV isolates into two genogroups (type I and II) and demonstrated the presence of genogroup II in Korea, indicating their geographic spread in East Asia. High sequence variations in region E of the FCV isolates emphasizes that a novel vaccine needs to be developed to induce protective immunity against various FCV strains.

Management of an Inappropriately Treated Case of Auricular Hematoma

Othematoma is a condition in which blood collects beneath the perichondral layer of the pinna. Recurrent auricular hematoma can be a challenging medical problem, with complications resulting in ear deformity, therefore, appropriate management is important. Improper treatment can result in a deformity known as ‘cauliflower ear’ or ‘wrestler’s ear.’ We report a case of othematoma that was inappropriately treated and present a review of current treatment options.

Analysis of Risk Factors for Myringosclerosis Formation after Ventilation Tube Insertion

Background@#This study examined possible risk factors for myringosclerosis formation after ventilation tube insertion (VTI). @*Methods@#A retrospective study was performed in a single tertiary referral center. A total of 582 patients who underwent VTI were enrolled in this study. Patients were divided into two groups based on the presence or absence of myringosclerosis: MS+ and MS−. Characteristics of patients were collected through medical chart review; these included age, gender, nature and duration of effusion, type of ventilation tube (VT), duration and frequency of VTI, incidence of post-VTI infection, incidence of intraoperative bleeding, and presence of postoperative perforation. Incidences of risk factors for myringosclerosis and the severity of myringosclerosis in association with possible risk factors were analyzed. @*Results@#Myringosclerosis developed in 168 of 582 patients (28.9%) after VTI. Patients in the MS+ group had an older mean age than those in the MS− group. The rates of myringosclerosis were higher in patients with older age, serous otitis media, type 2 VT, post-VTI perforation, and frequent VTI. However, there were no differences in occurrence of myringosclerosis based on gender, duration of effusion, duration of VT placement, incidence of post-VTI infection, or incidence of intraoperative bleeding. The severity of myringosclerosis was associated with the duration of effusion and frequency of VTI. @*Conclusion@#Older age, serous effusion, type 2 VT, presence of post-VTI perforation, and frequent VTI may be risk factors for myringosclerosis after VTI; the severity of myringosclerosis may vary based on the duration of effusion and frequency of VTI.

Analysis of Risk Factors for Myringosclerosis Formation after Ventilation Tube Insertion

Background@#This study examined possible risk factors for myringosclerosis formation after ventilation tube insertion (VTI). @*Methods@#A retrospective study was performed in a single tertiary referral center. A total of 582 patients who underwent VTI were enrolled in this study. Patients were divided into two groups based on the presence or absence of myringosclerosis: MS+ and MS−. Characteristics of patients were collected through medical chart review; these included age, gender, nature and duration of effusion, type of ventilation tube (VT), duration and frequency of VTI, incidence of post-VTI infection, incidence of intraoperative bleeding, and presence of postoperative perforation. Incidences of risk factors for myringosclerosis and the severity of myringosclerosis in association with possible risk factors were analyzed. @*Results@#Myringosclerosis developed in 168 of 582 patients (28.9%) after VTI. Patients in the MS+ group had an older mean age than those in the MS− group. The rates of myringosclerosis were higher in patients with older age, serous otitis media, type 2 VT, post-VTI perforation, and frequent VTI. However, there were no differences in occurrence of myringosclerosis based on gender, duration of effusion, duration of VT placement, incidence of post-VTI infection, or incidence of intraoperative bleeding. The severity of myringosclerosis was associated with the duration of effusion and frequency of VTI. @*Conclusion@#Older age, serous effusion, type 2 VT, presence of post-VTI perforation, and frequent VTI may be risk factors for myringosclerosis after VTI; the severity of myringosclerosis may vary based on the duration of effusion and frequency of VTI.

Development of a novel reverse transcription PCR and its application to field sample testing for feline calicivirus prevalence in healthy stray cats in Korea

Background@#Feline calicivirus (FCV) is a major and highly infectious pathogen in cats worldwide. However, there have been limited studies about the status of FCV infections in Korea. @*Objectives@#To investigate the current status of FCV infections in stray cats in Korea. @*Methods@#A novel reverse transcription polymerase chain reaction (RT-PCR) assay was developed based on the conserved nucleotide sequences of reported FCV strains. Field swab samples were collected from 122 cats (2 hospital admitted cats and 120 stray cats) in 2016 and 2017. All the samples were tested by virus isolation and 2 different RT-PCRs, including the novel RT-PCR, for the detection of FCV. @*Results@#The novel RT-PCR assay showed no cross-reactivity to the nucleic acids of the other feline pathogens tested, and the limit of detection was calculated as 10 0 TCID 50 /mL based on an in vitro assessment. The novel RT-PCR assay detected 5 positive samples from the 122 field samples, which showed perfect agreement with the results of the virus isolation method.In contrast, another RT-PCR assay used in a previous study in Korea detected no positive samples. The prevalence of FCV infection in stray cats was 2.5% (3/120) based on the results of virus isolation and the novel RT-PCR assays. @*Conclusions@#The current study is the first report of the detection and prevalence of FCV in stray cats in Korea. The novel RT-PCR assay developed in this study showed high sensitivity and specificity, which indicates a useful diagnostic assay to identify FCV infection in cats.

New genotype classification and molecular characterization of canine and feline parvoviruses

Background@#Canine parvovirus (CPV) and feline panleukopenia (FPV) cause severe intestinal disease and leukopenia. @*Objectives@#In Korea, there have been a few studies on Korean FPV and CPV-2 strains. We attempted to investigate several genetic properties of FPV and CPV-2. @*Methods@#Several FPV and CPV sequences from around world were analyzed by Bayesian phylo-geographical analysis. @*Results@#The parvoviruses strains were newly classified into FPV, CPV 2-I, CPV 2-II, and CPV 2-III genotypes. In the strains isolated in this study, Gigucheon, Rara and Jun belong to the FPV, while Rachi strain belong to CPV 2-III. With respect to CPV type 2, the new genotypes are inconsistent with the previous genotype classifications (CPV-2a, -2b, and -2c). The root of CPV-I strains were inferred to be originated from a USA strain, while the CPV-II and III were derived from Italy strains that originated in the USA. Based on VP2 protein analysis, CPV 2-I included CPV-2a-like isolates only, as differentiated by the change in residue S297A/N. Almost CPV-2a isolates were classified into CPV 2-III, and a large portion of CPV-2c isolates was classified into CPV 2-II. Two residue substitutions F267Y and Y324I of the VP2 protein were characterized in the isolates of CPV 2-III only. @*Conclusions@#We provided an updated insight on FPV and CPV-2 genotypes by molecular-basedand our findings demonstrate the genetic characterization according to the new genotypes.

Regulation of porcine endogenous retrovirus by dual LTR1+2 (Long Terminal Region) miRNA in primary porcine kidney cells

Porcine endogenous retroviruses (PERVs) integrate into germline DNA as proviral genome that enables vertical transmission from parents to their offspring. The provirus usually survives as part of the host genome rather than as an infectious agent, but may become pathogenic if it crosses species barriers. Therefore, replication-competent PERV should be controlled through selective breeding or knockout technologies. Two microRNAs (miRNAs), dual LTR1 and LTR2, were selected to inhibit the expression of PERV in primary porcine kidney cells. The inhibition efficiency of the miRNAs was compared based on their inhibition of different PERV regions, specifically long terminal repeats (LTRs), gag, pol, and env. Gene expression was quantified using real-time polymerase chain reaction and the C-type reverse transcriptase (RT) activity was determined. The messenger RNA (mRNA) expression of the PERV LTR and env regions was determined in HeLa cells co-cultured with primary porcine kidney cells. The mRNA expression of the LTR, gag, pol, and env regions of PERV was dramatically inhibited by dual miRNA from 24 to 144 h after transfection, with the highest inhibition observed for the LTR and pol regions at 120 h. Additionally, the RT activity of PERV in the co-culture experiment of porcine and human cells was reduced by 84.4% at the sixth passage. The dual LTR 1+2 miRNA efficiently silences PERV in primary porcine kidney cells.

Clinical Characteristics of Temporal Bone Metastases

OBJECTIVES: The purposes of this study were to evaluate the clinical characteristics of temporal bone metastasis (TBM) and to determine whether the characteristics differed according to primary malignancy. METHODS: We retrospectively analyzed data on 20 patients diagnosed with TBM between January 2000 and January 2017. Demographics, the period from diagnosis of primary malignancy to TBM diagnosis, the period from TBM diagnosis to death, the type and staging of primary malignancy, otologic manifestations, and TBM sites were assessed. After the primary malignancies were divided into solid cancers and hematologic malignancies, each parameter was compared between the two groups. RESULTS: The most common primary malignancy with TBM was lung cancer (45%). The most common otologic symptoms and signs were facial palsy (30.5%) and hearing loss (30.5%). The temporal squama (23%) and the facial nerve (20%) were the most commonly involved. Most TBMs occurred late in the disease process after the primary malignancy first metastasized to other organs. Hematologic malignancies metastasized significantly more frequently to the external auditory canal and the middle ear/mastoid compared to solid cancers (P=0.001 and P=0.004, respectively). CONCLUSION: If otologic manifestations such as facial palsy and hearing loss are presented in patients at advanced stages of malignancy, TBM of primary malignancy should be suspected. In addition, hematologic malignancies tend to metastasize to the external auditory canal and the middle ear cleft more commonly than solid cancers do.

Does Transcranial Direct Current Stimulation Have a Role in the Treatment of Tinnitus?

No abstract available.

Blind Sac Approach Using Silastic Block for Cochlear Implantation in Patients with Cholesteatoma

Cochlear implant (CI) surgery in cholesteatoma is challenging because of the risk of residual or recurrent infection. Although CI could be done with subtotal petrosectomy in single or staged surgery, this surgery needed additional surgical procedures to obliterate the mastoid cavity. This paper describes a new surgical technique for CI surgery in cholesteatoma without external auditory canal closure.

Blind Sac Approach Using Silastic Block for Cochlear Implantation in Patients with Cholesteatoma

Cochlear implant (CI) surgery in cholesteatoma is challenging because of the risk of residual or recurrent infection. Although CI could be done with subtotal petrosectomy in single or staged surgery, this surgery needed additional surgical procedures to obliterate the mastoid cavity. This paper describes a new surgical technique for CI surgery in cholesteatoma without external auditory canal closure.

Evaluation of the correlation between gross lung score and microscopic diagnosis for swine pneumonia in Korean slaughterhouses

To reduce swine production costs, a slaughter check system has been developed in countries with an advanced swine industry. Evaluation of lung lesions in carcasses is a critical part of the slaughter check system. This study was performed to collect background information for use in developing a slaughter check system in Korea. Lung tissues and their gross images were collected from slaughterhouses in Gyeonggi-do, Korea. Scoring of the gross lung lesions was performed on the lung images. Histopathologic examination was conducted to classify the pulmonary lesions as bronchopneumonia or interstitial pneumonia. Scores of the gross lung lesions were significantly different between bronchopneumonia and interstitial pneumonia groups (p < 0.001). A 90% confidence interval of gross lung lesion scores was established for the bronchopneumonia group, and the lesion scoring had a sensitivity of 100% and specificity of 77.3%. The gross lung lesion scoring test was subjected to a diagnostic distinction evaluation by examining the receiver operating characteristic curve and was appraised as having good discrimination for bronchopneumonia. Establishment of a gross lung lesion scoring test for the diagnosis of bronchopneumonia could be valuable as a screening test of macroscopic bronchopneumonia in swine slaughter check system.

A Case of Scala Vestibuli Cochlear Implantation in Tympanogenic Labyrinthitis Ossificans / 대한이비인후과학회지

Labyrinthitis ossificans (LO) is a pathologic formation of fibrosis and new bone within the lumen of the otic capsule. The LO is a challenging issue in cochlear implantation since obliteration and obstruction of the cochlea make electrode insertion through scala tympani (classic route) difficult. Moreover, tympanomastoidectomy for resolution of chronic otitis media is also simultaneously considered for tympanogenic LO with severe to profound hearing loss because ossification could progress in case of staged or delayed implantation after initial tympanomastoidectomy. We report a patient with tympanogenic LO, who received subtotal petrosectomy with simultaneous cochlear implantation via scala vestibuli instead of the scala tympani for hearing rehabilitation.

Mechanisms of quinolone resistance in Escherichia coli isolated from companion animals, pet-owners, and non-pet-owners

The present study investigated the prevalence and mechanisms of fluoroquinolone (FQ)/quinolone (Q) resistance in Escherichia (E.) coli isolates from companion animals, pet-owners, and non-pet-owners. A total of 63 E. coli isolates were collected from 104 anal swab samples, and 27 nalidixic acid (NA)-resistant isolates were identified. Of those, 10 showed ciprofloxacin (CIP) resistance. A plasmid-mediated Q resistance gene was detected in one isolate. Increased efflux pump activity, as measured by organic solvent tolerance assay, was detected in 18 NA-resistant isolates (66.7%), but was not correlated with an increase in minimum inhibitory concentration (MIC). Target gene mutations in Q resistance-determining regions (QRDRs) were the main cause of (FQ)Q resistance in E. coli. Point mutations in QRDRs were detected in all NA-resistant isolates, and the number of mutations was strongly correlated with increased MIC (R = 0.878 for NA and 0.954 for CIP). All CIP-resistant isolates (n = 10) had double mutations in the gyrA gene, with additional mutations in parC and parE. Interestingly, (FQ)Q resistance mechanisms in isolates from companion animals were the same as those in humans. Therefore, prudent use of (FQ)Q in veterinary medicine is warranted to prevent the dissemination of (FQ)Q-resistant bacteria from animals to humans.

A Case of Free-Floating Endolymph Particle Found during Transmastoid Posterior Semicircular Canal Occlusion for Intractable Posterior Canal Benign Paroxysmal Positional Vertigo / 대한이비인후과학회지

Benign paroxysmal positional vertigo (BPPV) is a common inner ear cause of vertigo, most of which can be treated by particle repositioning maneuver (PRM). However, in rare cases, positional vertigo could persist or frequently recur after several PRM. In these intractable cases, surgical treatments including singular neurectomy and semicircular canal occlusion have been used. Posterior semicircular canal occlusion has some advantages over singular neurectomy in hearing preservation and feasible surgical technique. Also free-floating endolymph particles causing intractable BPPV are known to occur in about 20% of the cases during canal occlusion surgery. Nevertheless, to the best of our knowledge, there has not been any report on the identification of those particles in the Korean literature. In this paper, we report a case of free-floating endolymph particle found during transmastoid posterior semicircular canal occlusion for intractable posterior canal BPPV.

Intra-Tympanic Steroid Treatment Alone as an Initial Treatment for the Patients with Severe or Profound Sudden Sensorineural Hearing Loss and Medical Problems in Steroid Use / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: We investigated the feasibility of intra-tympanic steroid injection (ITS) treatment alone for patients with severe or profound sudden sensorineural hearing loss (SSNHL), who have medical problems in systemic steroid use. SUBJECTS AND METHOD: Medical records of 43 patients from March 2012 to March 2014 were investigated. Patients who did not have any medical problems in steroid use were treated by systemic steroid but patients with medical problems were treated by ITS alone. RESULTS: Systemic steroid was used in 32 patients, and 11 patients were treated by ITS alone. The mean follow up periods were 6.5±1.4 weeks for ITS only, and 6.5±2.6 weeks for the systemic steroid group. In the final audiometry results, the mean hearing level and the mean gain of affected ear in the two groups were not different, and the mean differences with unaffected ear in the two groups showed no differences. However, five patients of systemic steroid group recovered completely by Siegel's criteria. CONCLUSION: ITS only therapy for SSNHL is considered a great alternative for patients whose condition does not allow systemic steroid therapy.

Isolation and characterization of antimicrobial-resistant Escherichia coli from national horse racetracks and private horse-riding courses in Korea

Limited information is available regarding horse-associated antimicrobial resistant (AR) Escherichia (E.) coli. This study was designed to evaluate the frequency and characterize the pattern of AR E. coli from healthy horse-associated samples. A total of 143 E. coli (4.6%) were isolated from 3,078 samples collected from three national racetracks and 14 private horse-riding courses in Korea. Thirty of the E. coli isolates (21%) showed antimicrobial resistance to at least one antimicrobial agent, and four of the AR E. coli (13.3%) were defined as multi-drug resistance. Most of the AR E. coli harbored AR genes corresponding to their antimicrobial resistance phenotypes. Four of the AR E. coli carried class 1 integrase gene (intI1), a gene associated with multi-drug resistance. Pulsed-field gel electrophoretic analysis showed no genetic relatedness among AR E. coli isolated from different facilities; however, cross-transmissions between horses or horses and environments were detected in two facilities. Although cross-transmission of AR E. coli in horses and their environments was generally low, our study suggests a risk of transmission of AR bacteria between horses and humans. Further studies are needed to evaluate the risk of possible transmission of horse-associated AR bacteria to human communities through horse riders and horse-care workers.

Stem Cell Therapy for Sensorineural Hearing Loss, Still Alive?

In mammals, the auditory system, which includes the cochlea, has a very complex structure harboring many types of cells performing different functions. Among these cells are the auditory hair cells (HCs), which are terminally and well differentiated unique cells which have lost their regenerative potential after development. The auditory HCs are easily damaged by aging as well as during episodes of ototoxicity and acoustic trauma. HCs damages typically occur in the early stage of injury and can result a permanent hearing loss. Recently, there have been tremendous developments from stem cells (SCs) research involving sensorineural hearing loss, but several limitations and obstacles persist in allowing these developments from continuing onto clinical applications. This review discusses the recent advances in SC research in sensorineural hearing loss with the subsequent sections discussing the possible hurdles and limitations that currently preclude their clinical application.