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Biomedical subjects

J H Shin

Publications and source records attributed to J H Shin.

At least 19 recordsLinked to original sources
PubMed2006

Prevalence of non-tuberculous mycobacteria in a hospital environment.

In recent years, non-tuberculous mycobacteria (NTM) have emerged as an important cause of opportunistic nosocomial infections but there is little known about the isolation and identification of NTM in Korea. The aim of this study was to assess the prevalence of NTM in the hospital environment and identify the species. A total of 150 samples were collected from different parts of the hospital. NTM were isolated and identified by restriction fragment length polymorphism analysis of the gene encoding rpoB and partial sequencing analysis of hsp65 and rpoB. In this study, 60 strains of NTM were isolated from 50 of the 150 samples. Half of the tap water samples (50 of 100) were positive for mycobacteria. An estimated 73.3% of the isolates were saprophytic, 21.7% were potentially pathogenic and 5% were unidentified. The presence of NTM in hospital tap water is not uncommon. Such water isolates might cause true nosocomial infection in immunocompromised patients, in addition to the risk of false-positive culture results.

Bacterial Proteins↗
PubMed2006

Malignant esophageal-tracheobronchial strictures: parallel placement of covered retrievable expandable nitinol stents.

PURPOSE: To assess the safety and clinical effectiveness of the parallel placement of covered retrievable expandable metallic stents in the palliative treatment of malignant esophageal and tracheobronchial strictures. MATERIAL AND METHODS: Under fluoroscopic guidance, parallel stents were placed in 12 symptomatic patients with both malignant esophageal and tracheobronchial strictures. Seven of these 12 patients also had an esophagorespiratory fistula (ERF) and one patient had an esophagocutaneous fistula. Technical success, clinical improvement, complications, and survival rates were evaluated. RESULTS: A total of 28 esophageal and airway stents were successfully placed. The grade of dysphagia and dyspnea score significantly decreased after stent placement (P=0.002 and 0.003, respectively). ERF and esophagocutaneous fistula were sealed off in all eight patients after esophageal stent placement; however, the esophagocutaneous fistula reopened 1 month later. Complications included stent migration or expectoration (n=3), tracheal compression by the esophageal stent (n=3), new fistula development due to covering membrane degradation of the esophageal stent (n=1), and symptomatic sputum retention (n=1). Stent removal was easily performed for two stents; one migrated stent and the other with covering membrane degradation. All 12 patients died within the mean survival period of 72.50 days (range 7-375 days). CONCLUSION: Parallel placement of covered retrievable expandable metallic stents is safe and effective for the palliative treatment of malignant esophageal and tracheobronchial strictures.

Adult↗
PubMed2006

Value of repeat ultrasound-guided fine-needle aspiration in nodules with benign cytological diagnosis.

PURPOSE: To assess the value of repeat ultrasound-guided fine-needle aspiration (US-FNA) in nodules with benign cytological diagnosis. MATERIAL AND METHODS: One-hundred-and-eighty-seven patients undergoing repeat US-FNA were included after a benign cytological diagnosis had been made by the initial US-FNA. They were divided into a re-aspiration group, who underwent repeat US-FNA within 6 months for a discordant pathological and clinico-radiological result, and a follow-up aspiration group, who underwent repeat US-FNA after 6 months without any clinical or radiological suspicion. The cancer rate in each group and the US findings of the later-diagnosed malignant nodules were assessed. RESULTS: Nine malignancies were verified in the 187 cases (4.8%) by repeat US-FNA or surgery. In 44 patients in the re-aspiration group, 6 malignancies were identified (13.6%), compared with 3 malignancies in the 143 patients in the follow-up aspiration group (2.1%) (P<0.05). The later-diagnosed malignant nodules were an average of 1.0 cm in diameter; 66.7% were round; 66.7% were circumscribed; 100% were solid; 88.9% were hypoechoic; and 55.6% contained calcifications on US. CONCLUSION: The follow-up of nodules with benign cytological diagnosis without clinicoradiological suspicion of malignancy is warranted using imaging surveillance rather than repeated US-FNA.

Adult↗
PubMed2006

Microinvasive ductal carcinoma arising within a fibroadenoma: A case report.

Fibroadenomas are among the most common benign breast tumors in which carcinomas rarely develop. We report the imaging findings of a microinvasive ductal carcinoma arising within a fibroadenoma in a 51-year-old woman. This mass showed coarse heterogeneous microcalcifications within a circumscribed mass on mammography, a heterogeneous hypoechoic mass on ultrasound, and an early enhancing mass on magnetic resonance imaging. Although a fibroadenoma in an older woman appears benign-looking, the presence of any unusual signs should raise concerns about malignancy.

Breast Neoplasms↗
PubMed2006

Deep tracheal laceration after balloon dilation for benign tracheobronchial stenosis: case reports of two patients.

We report two cases of deep tracheal laceration in female patients after balloon dilation for benign tracheobronchial stenosis. Immediate post-procedure bronchoscopy and CT including 3D reconstructions showed deep lacerations in the posterior tracheal wall. Clinically, the patients' dyspnoea subsided and there has been no recurrence during follow-up after balloon dilation. On the follow-up 3D-reconstructed CT scans obtained 2 months and 8 months following balloon dilation, respectively, the lacerations had healed completely and there was considerable improvement in lumen size.

Adult↗
PubMed2006

A case of successful embolotherapy for gastric ulcer bleeding from the intercostal artery after oesophagectomy and gastric reconstruction.

We report a successful treatment with coil embolisation of an intercostal artery for ulcer bleeding in a gastric tube in a 70-year-old man who underwent a total oesophagectomy and gastric tube reconstruction for oesophageal cancer. This case teaches us to search aberrant feeding vessels when active bleeding is suspected in reconstructed gastric tube in the patient with oesophagectomy and oesophagogastrostomy.

Aged↗
PubMed2005

Usefulness of the carina as a radiographic landmark for central venous catheter placement in paediatric patients.

BACKGROUND: Several reports have proposed radiographic landmarks for the proper positioning of central venous catheters (CVC). The carina is one of the proposed landmarks in adults. Here, we evaluate the possibility of using the carina as a radiographic landmark for the identification of proper positioning of the CVC tip in paediatric patients. METHODS: We studied 57 right internal jugular vein catheterizations in infants and children undergoing surgery for the treatment of congenital heart disease. After placing the CVC tip at the junction of the superior vena cava and the right atrium (SVC-RA junction) via intraoperative transoesophageal echocardiography, and by taking postoperative anterior-posterior chest radiographs, we measured the longitudinal distance from the carina to the SVC-RA junction, using the Picture Archiving and Communicating System. RESULTS: The average distance between the carina and the SVC-RA junction was 1.5 cm (95% CI 1.3-1.8 cm). No catheter tip was above the carina. Although there was no particular relationship between this distance and the patient's age, height, or weight, the distance between the carina and the SVC-RA junction tended to be more variable in younger and smaller children. CONCLUSIONS: The carina can be used as a radiographic landmark for the proper CVC tip placement in paediatric patients. If the tip of the CVC is not distal to the carina the chances are minute that it is in the right atrium.

Adolescent↗
PubMed2005

Identification and characterization of the peroxiredoxin gene family in chickens.

Peroxiredoxin (PRX) is a crucial antioxidant protein that protects against endogenously produced peroxides in prokaryotes to eukaryotes. To date, 6 different isoforms have been identified in mammals. In this study, we describe the first members of the PRX protein family to be characterized in Chicken. Through bioinformatics analysis, we observed that at least 4 different classes of PRX protein have been evolutionarily conserved in chickens. Furthermore, in vitro functional assays of the candidate chicken PRX proteins demonstrated that they had levels of antioxidant activity similar to those of the mammalian enzymes. The expression patterns of the PRX transcript in several chicken tissues were not tissue specific, suggesting that they might play an essential role as a housekeeping gene in all tissues to protect against oxidative damage. In conclusion, the sequences of the putative members of this functional gene family in chickens could be effectively retrieved in silico through bioinformatics analysis, and the functionality of their gene products evaluated by in vitro comparative assay.

Animals↗
PubMed2005

The genetic and phenotypic basis of blood group A subtypes in Koreans.

A serological and genetic study of Korean blood donors with phenotypic group A subtypes was performed. There were 176 donors with phenotypic A subtypes identified. Exons 6 and 7 from 57 representative donors were sequenced. The A(var) allele (784 G > A) was cloned and sequenced, and a family study demonstrating its inheritance and unusual serological characteristics was performed. The A102 allele was the most frequently identified allele in phenotypically A2 (58%, 11/19) and A2B (68%, 17/25) donors. Anti-A1 was rarely present amongst A2 and A2B donors. The family study revealed that the A(var) allele was expressed as phenotype A(weak)B in A(var)/B heterozygote members, but as phenotype O in A(var)/O heterozygotes. The most frequent allele in Korean donors with the A2 phenotype differs from its Caucasian counterpart, as does the frequency of anti-A1. The A(var) allele demonstrates allelic enhancement in A(var)/B heterozygotes.

ABO Blood-Group System↗
PubMed2005

Analysis of testis-specific transcripts in the chicken.

Sequences of candidate chicken testis-specific genes were analysed in order to develop a resource for functional genomic studies of the testis and male germ cells. Tentative consensus sequences (TC) containing expressed sequence tags expressed in testis libraries were selected from the TIGR Gallus gallus Gene Index, resulting in 292 TC. The transcriptional expression of these genes were evaluated in several chicken tissues, including testis and ovary. One hundred ten of the 292 TC were expressed in a testis-specific manner. Annotation of the TC using the Gene Ontology database terms showed that the proportion of testis-specific TC that were classified as having catalytic activity (within the molecular function branch) was higher than the proportion of total chicken TC classified in the same way. Our results may facilitate the investigation of testis-specific genes and their functional analysis in the chicken, as well as in other avian species.

Animals↗
PubMed2005

A set of testis-specific novel genes collected from a collection of Korean Native Chicken ESTs.

We report a set of testis-specific novel genes by comparing the The Institute for Genomic Research (TIGR) chicken gene index with the 13,132 expressed sequence tag (EST) collection from Korean Native Chicken (KNC). A total of 553 novel transcripts have resulted after comparison of our EST contigs and singlets against the chicken gene index and chicken genome sequences. Interestingly, 76% of the new genes were from testis-specific EST contigs or singlet and analysis of exon/intron structure showed that a significant number of the contigs have intronless coding regions. A large portion of the testis-specific transcripts have intronless coding region indicating that the testis-specific expression pattern is related to a group of single exon genes in the chicken. The chicken EST data that are described in this paper have been submitted to the NCBI dbEST under accession numbers CO759017-CO764274, CO765331-CO768903 and CO769672-CO773972.

Animals↗
PubMed2005

Feasibility study on the removal of nitrous compounds with a hollow-fiber membrane biofilm reactor.

The objective of this study was to develop an integrated nitrogen treatment system using autotrophic organisms. A treatment system consists of an aerobic hollow-fiber membrane biofilm reactor (HfMBR) and anaerobic HfMBR. In the aerobic HfMBR, a mixture gas of air and O2 was supplied through the fibers for nitrification. Denitrification occurred in the anaerobic HfMBR using H2 as the electron donor. The treatment system was continuously operated for 190 days. NH4-N removal efficiencies ranging from 95% to 97% were achieved at NH4-N concentrations of influent ranging from 50 to 100 mg N/L. When glucose was added to the influent, the simultaneous nitrification and denitrification occurred in the aerobic HfMBR, and nitrogen removal rates were changed according to the COD/NH4-N ratio of influent. In the anaerobic HfMBR, autotrophic denitrification using H2 occurred and the removal rates achieved in this study were 23-58 mg N/m2 d. In this study, the achieved removal efficiency was lower than other study findings; however, the result suggested that this hybrid HfMBR system can be used effectively for nitrogen removal in oligotrophic water.

Aerobiosis↗
PubMed2004

Scaling of F-actin network rheology to probe single filament elasticity and dynamics.

The linear and nonlinear viscoelastic response of networks of cross-linked and bundled cytoskeletal filaments demonstrates remarkable scaling with both frequency and applied prestress, which helps elucidate the origins of the viscoelasticity. The frequency dependence of the shear modulus reflects the underlying single-filament relaxation dynamics for 0.1-10 rad/sec. Moreover, the nonlinear strain stiffening of such networks exhibits a universal form as a function of prestress; this is quantitatively explained by the full force-extension relation of single semiflexible filaments.

Actins↗
PubMed2004

Relating microstructure to rheology of a bundled and cross-linked F-actin network in vitro.

The organization of individual actin filaments into higher-order structures is controlled by actin-binding proteins (ABPs). Although the biological significance of the ABPs is well documented, little is known about how bundling and cross-linking quantitatively affect the microstructure and mechanical properties of actin networks. Here we quantify the effect of the ABP scruin on actin networks by using imaging techniques, cosedimentation assays, multiparticle tracking, and bulk rheology. We show how the structure of the actin network is modified as the scruin concentration is varied, and we correlate these structural changes to variations in the resultant network elasticity.

Actin Cytoskeleton↗
PubMed2004

Elastic behavior of cross-linked and bundled actin networks.

Networks of cross-linked and bundled actin filaments are ubiquitous in the cellular cytoskeleton, but their elasticity remains poorly understood. We show that these networks exhibit exceptional elastic behavior that reflects the mechanical properties of individual filaments. There are two distinct regimes of elasticity, one reflecting bending of single filaments and a second reflecting stretching of entropic fluctuations of filament length. The mechanical stiffness can vary by several decades with small changes in cross-link concentration, and can increase markedly upon application of external stress. We parameterize the full range of behavior in a state diagram and elucidate its origin with a robust model.

Actin Cytoskeleton↗
PubMed2004

A novel B(var) allele (547 G>A) demonstrates differential expression depending on the co-inherited ABO allele.

BACKGROUND AND OBJECTIVES: Genetic analysis of group B donors in Korea was performed. MATERIALS AND METHODS: Exons 6 and 7 were sequenced in 12 phenotypically B3 donors 6 B3, 6 A1B3. RESULTS: Consensus sequences all B3 and 2/6 A1B3 donors were present. Four A1B3 donors demonstrated a novel B allele, B(var), in the context of A101/ or A102/B(var) genotypes. Family studies based on an A1B3 donor with the B(var) allele and on another unrelated subject with identical genotype and phenotype revealed B(var)/O01 genotypes with full B-antigen expression. CONCLUSIONS: B(var) allele is subject to differential expression, depending on the co-inherited ABO allele.

ABO Blood-Group System↗