Biomedical subjects

Jeong Hwan Kim

Publications and source records attributed to Jeong Hwan Kim.

15 recordsLinked to original sources

PubMed2006

Conversion of sucrose into isomaltulose by Enterobacter sp. FMB1, an isomaltulose-producing microorganism isolated from traditional Korean food.

Over 500 microorganisms isolated from Korean traditional foods, Maeju (source of soybean paste) and Nuruk (Korean koji), were screened to obtain an isomaltulose-producing microorganism. It was identified as Enterobacter sp. FMB-1 by 16S rRNA sequencing and the API 20E system. It had a greater than 90% conversion of sucrose (as 4 g/l) to isomaltulose in 2 days. Small amounts of trehalulose, glucose, and fructose were produced as byproducts, implying that this strain could be possibly employed in the production of isomaltulose in industry.

Enterobacter↗

PubMed2006

Characterization of pFMBL1, a small cryptic plasmid isolated from Leuconostoc mesenteroides SY2.

A 4661bp cryptic plasmid, pFMBL1, was isolated from Leuconostoc mesenteroides SY2, an isolate from Kimchi, and characterized. Nucleotide sequence analysis revealed two open reading frames, orf1 and orf2. orf2 was 453bp in size and its translation product had 58% identity with a putative protein possibly involved in the replication of pTXL1, a cryptic plasmid from L. mesenteroides ssp. mesenteroides Y110. RNA transcript from orf2 was detected but not from orf1 or intergenic region. Minimum 3.5kb fragment encompassing orf1 and orf2 was required for the replication of pFMBL1 and employed for the construction of Escherichia coli-Leuconostoc shuttle vector, pSJ33E. L. mesenteroides SY1 (another Kimchi isolate), Leuconostoc ssp., and Lactobacillus brevis were successfully transformed with pSJ33E, and the transformation efficiencies were ranged between 1.1x10(1) and 4x10(5)transformants/microg DNA. No single-stranded DNA intermediate was detected from L. mesenteroides SY1 cells harboring pSJ33E, indicating that pFMBL1 probably replicated via theta-type mechanism. pSJ33E was stably maintained in L. mesenteroides SY1 in the absence of erythromycin (Em, 5 microg/ml) and after 1 month of daily subculturing in MRS broth without selective pressure, three percent of cells still retained pSJ33E.

Base Pairing↗

PubMed2006

Effects of abdominal electroacupuncture on parameters related to obesity in obese women: a pilot study.

The aim of this study was to elucidate the effects of electroacupuncture at abdominal meridian points on various obesity-related parameters: body weight (BW), body fat (BF) percentage, body mass index (BMI), percent ideal body weight (PIBW), and waist (WC) and hip (HC) circumferences. All of these parameters changed significantly compared to pretreatment in this pilot uncontrolled study involving 31 women with obesity. The percent reductions were 5.3% in BW, 1.3% in BF, 4.7% in BMI, 6.0% in PIBW, 4.6% in WC, 6.2% in HC, and 2.1% in the WC/HC ratio. The most affected variable was WC (effect size=0.58). Since this was a pilot study with several limitations, such as a small sample size and absence of a control treatment and appropriate follow-up, further studies that include a randomized design, larger sample sizes, and more detailed data about the subjects are needed to convincingly show the effects of electroacupuncture at abdominal meridian points on overweight and obese patients.

Adipose Tissue↗

PubMed2006

Isolation and characterization of promoters from Lactococcus lactis ssp. cremoris LM0230.

DNA fragments showing promoter activity were obtained from the chromosomal DNA of Lactococcus lactis ssp. cremoris LM0230 by using a promoter-screening vector pBV5030, which contains a promoterless chloramphenicol acetyltransferase gene. Ten fragments were identified based on their ability to confer resistance against chloramphenicol in Escherichia coli. DNA sequencing revealed that all the fragments had a consensus region recognized by the sigma factor and only the nucleotide sequence of fragment 15C had the identical consensus region with the promoter P2 from L. lactis ssp. lactis MG1614. To compare their promoter strengths, an E. coli-lactococcal shuttle vector pWL1 containing a luciferase gene as the reporter gene was constructed based on lactococcal plasmid pMG36e. The putative promoter regions of 10 fragments exhibiting promoter activity were characterized in E. coli and L. lactis by measuring the luciferase activity, among which the putative promoter P6C exhibited the highest promoter activity both in E. coli JM109 and L. lactis ssp. cremoris MG1363. The luciferase system endowed significantly different expression levels enough to compare promoter strengths in E. coli and lactococcal host. The transcription-initiation sites of P6C and P13C were mapped by primer extension, which showed that they corresponded to a purine residue. The characterized promoters could be useful for the industrial production of heterologous proteins in L. lactis in case the proteins require a high safety level.

Base Sequence↗

PubMed2006

Clinical features and prognosis of hepatocellular carcinoma in young patients from a hepatitis B-endemic area.

BACKGROUND AND AIM: Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. However, the clinical features of young HCC patients have not been fully studied. In the present study, we investigated the prevalence, clinical characteristics and prognosis of young HCC patients. METHODS: A retrospective analysis was performed for HCC patients in our center using Korean cancer registry data. Among 4234 patients enrolled, there were 38 patients younger than 30 years of age (0.9%). We compared clinical characteristics and survival data of these patients (group I) with those of sex-matched, randomly selected HCC patients aged 30-59 years (group II; n = 231) and 60 years or older (group III; n = 147). RESULTS: Group I showed distinct features compared with groups II and III as follows: low frequency of smoking history, high positive rate of hepatitis B s antigen, no association with anti-hepatitis C virus antibody, high frequency of alpha-fetoprotein > or = 400 ng/mL, well-preserved liver function, larger tumor size, more advanced tumor-node-metastasis (TNM) stage and Cancer of the Liver Italian Program (CLIP) score and more frequent application of surgical resection and chemotherapy as initial treatment. The overall survival of group I was worse than that of group II, but similar to that of group III. Multivariate analysis showed that TNM stage and CLIP score, not age itself, were independent predictive factors for survival. CONCLUSIONS: The results suggest that young HCC patients tend to have a poor prognosis owing to advanced tumor stage, despite well-preserved liver function and aggressive treatment. Further studies regarding the role of HCC screening in young people may be useful, especially in hepatitis B virus carriers from high endemic areas.

Adult↗

PubMed2006

[Microsatellite instability in gastric B-cell lymphoma].

BACKGROUND/AIMS: Microsatellite instability (MSI) reflects the defect in DNA mismatch repair (MMR) pathways and plays an important role in certain malignancies. However, the role of MSI in the development of gastric B-cell lymphomas remains unsettled. We aimed to investigate the clinical significance of MSI in patients with gastric B-cell lymphoma. METHODS: Seven micosatellite loci (BAT25, BAT26, D2S123, D5S346, D17S250, D14S50, IGF-IIR) were used for MSI analyses. Microsatellite genotypes were categorized as microsatellite stable (MSS, no positive marker), low frequency MSI (MSI-L,<40% positive marker) and high frequency MSI (MSI-H, >40% positive marker). Among the gastric B-cell lymphoma patients who underwent MSI analysis between September 2002 and May 2003, twenty-two patients were enrolled. Median follow-up duration was 23 months (6-32 months). RESULTS: Median age was 46 years (26-73 years). Male to female ratio was 1:1.4. Twelve patients (54.5%) underwent Helicobacter pylori (H. pylori) eradication and ten patients (45.5%) underwent chemoradiation therapy. No case presented MSI-H. MSI-L was observed in 40.9% (9/22). Between MSS group and MSI-L group, there was no significant difference in age, tumor stage, location, grade of large cell component, H. pylori infection, bulk of tumor and proportion of regression or recurrence. All positive markers belonged to the dinucleotide markers. CONCLUSIONS: The current study suggests that the role of MSI is questionable in the development of gastric B-cell lymphoma due to their low incidence.

Adult↗

PubMed2006

[Peginterferon alfa-2a plus ribavirin for initial treatment of chronic hepatitis C in Korea].

BACKGROUND/AIMS: Combination therapy with peginterferon and ribavirin is a standard therapy for western patients with chronic hepatitis C; however, its efficacy remains unclear in East Asian patients. We evaluated the efficacy and safety of administering peginterferon alfa-2a plus ribavirin in native Korean patients with chronic hepatitis C. METHODS: Seventy-five patients with detectable HCV RNA (52.0% male, median age: 50.8 years) were eligible for the study. The patients were treated with peginterferon alfa-2a 180 mcg/week plus ribavirin 800 mg/day for 24 weeks (for genotype non-1, n=46) or 1000-1200 mg/day for 48 weeks (for genotype 1, n=29). The early virologic response (EVR), the end of treatment virologic response (ETVR), the sustained virologic response (SVR), the biochemical response and the adverse event were analyzed. RESULTS: EVR was seen in 86.2% of the patients with genotype 1. The ETVR was 58.6% in the genotype 1 group and 84.8% in the genotype non-1 group (P=0.02). The overall SVR was 70.7%: 55.2% in the genotype 1 group and 80.4% in the non-1 group (P=0.04). The sustained biochemical response was 64.0%. Multivariate analysis showed that the baseline HCV RNA level (Odds ratio: 0.045, 95% CI: 0.011-0.183, P<0.001) and genotype (Odds ratio: 0.247, 95% CI: 0.063-0.969, P=0.045) had an independent effect on the SVR. Neutropenia, anemia, flu-like symptoms and itching were the common adverse events. Aggravated liver function led to discontinuation of therapy for six patients. Dose modification in twenty-nine patients was effective without producing a significant reduction of the SVR. CONCLUSIONS: Our data suggest that the efficacy of peginterferon plus ribavirin therapy in Koreans is comparable to those from studies on Western patients as an initial treatment for chronic hepatitis C patients. The baseline HCV RNA level and the genotype can be significant factors influencing the SVR.

Adult↗

PubMed2005

Cloning and characterization of the bifunctional alcohol/acetaldehyde dehydrogenase gene (adhE) in Leuconostoc mesenteroides isolated from kimchi.

A bifunctional alcohol/acetaldehyde dehydrogenase (AdhE) gene (adhE) was cloned from Leuconostoc mesenteroides C7 (LMC7), which is the dominant lactic acid bacterium produced during heterofermentation of kimchi. The nucleotide sequence of the DNA fragment containing putative adhE, which is 2685 bp long and encodes an 886 amino acid polypeptide, exhibits 99% homology with Leu. mesenteroides sp. cremoris. The deduced AdhE comprises two conserved domains: alcohol dehydrogenase (Adh) and acetaldehyde dehydrogenase (Aldh). Moreover, two NAD-binding sites were observed, based on the presence of the GXGXXG motif. A pADHE containing the adhE gene expressed AdhE at the translational level in Escherichia coli BL21, which was at a higher level than in E. coli DH5alpha and E. coli JM109. The AdhE of LMC7 showed Adh and Aldh activities that, when expressed in E. coli. BL21, were 7.5 and 5.7 U mg(-1) , respectively.

Alcohol Dehydrogenase↗

PubMed2005

Cloning and characterization of the gene encoding phosphoketolase in Leuconostoc mesenteroides isolated from kimchi.

The gene encoding phosphoketolase, which is 2749 bp long and contains 814 amino acid polypeptides with a total molecular mass of 91.9 kDa, was cloned from Leuconostoc mesenteroides C7 (LMC7) and expressed in Escherichia coli. It exhibited a homology of >58% with phosphoketolases from other lactic acid bacteria. The phosphoketolase of LMC7 belongs to the xylulose 5-phosphate (X5P)/fructose 6-phosphate (F6P) phosphoketolase (Xfp) family, which is an enzyme with dual specificity for X5P and F6P. The members of this family contain typical thiamin pyrophosphate (TPP) binding sites as reported for other TPP-dependent enzymes, and several highly conserved regions as signature patterns for phosphoketolases. The plasmid pGPK containing the Xfp gene (xfp) exhibits phosphoketolase activity in E. coli. The specific activities of the enzyme from E. coli BL21 and E. coli EC101 harboring xfp were 0.28 and 0.14 units/mg, respectively. They both exhibited a 1.5-fold increase in the production of acetic acid from acetyl phosphate compared with their corresponding original strain.

Aldehyde-Lyases↗

PubMed2004

Characterization of pC7 from Lactobacillus paraplantarum C7 derived from Kimchi and development of lactic acid bacteria--Escherichia coli shuttle vector.

A cryptic plasmid pC7 was characterized, which was isolated from Lactobacillus paraplantarum C7 derived from Kimchi, a traditional korean vegetable food. The plasmid pC7 is a circular molecule of 2,134 base-pairs in length with a G + C content of 38.5%. The nucleotide sequence analysis revealed the presence of an open reading frame encoding a putative 317 amino acids protein homologous to replication proteins RepA. Furthermore, a putative double and a single-strand origin were identified. Together with features of nucleotide sequences, the detection of single-stranded intermediate DNA in Lb. paraplantarum demonstrated that pC7 replicates via a rolling circle mechanism. A cloning vector for lactic acid bacteria was developed on the basis of the pC7 replicon, into which were inserted an erythromycin resistance gene as a marker, multiple cloning sites, and Escherichia coli ColE1 replication origin. E. coli and several species of Lactobacillus and Leuconostoc can be transformed with the resultant vector. Therefore, pC7 derivatives may be useful LAB-E. coli shuttle vectors, which are essential in engineering important strains in food fermentation.

Amino Acid Sequence↗

PubMed2004

Efficacy of electrolyzed acid water in reprocessing patient-used flexible upper endoscopes: Comparison with 2% alkaline glutaraldehyde.

BACKGROUND AND AIM: Two percent glutaraldehyde, the most widely used liquid chemical germicide (LCG), may be hazardous to patients and medical personnel. Alternatives to glutaraldehyde, such as electrolyzed acid water (EAW), are being developed, but data from well-controlled studies with patient-used endoscopes are rare. The purpose of the present paper was to evaluate the high-level disinfection capability of EAW and compare it with glutaraldehyde. METHODS: A random sample of 125 endoscopes was collected immediately after upper endoscopic examination. After careful manual cleaning, endoscopes were divided into a glutaraldehyde and EAW group. After the disinfection procedure, samples from working channel (S-1), insertion tube (S-2), umbilical cord (S-3), and angulation knob (S-4) were taken and cultured. Another twenty endoscopes were experimentally contaminated with hepatitis B virus (HBV) and samples were collected after contamination (T-1), after manual cleaning (T-2), and after final disinfection (T-3). Polymerase chain reaction (PCR) for HBV-DNA was performed. RESULTS: In the EAW group, culture-positive rates were 3.2% in S-1, 9.5% in S-2, 3.2% in S-3, and 27.0% in the S-4 samples. There was no significant difference between the EAW and glutaraldehyde groups for all sampling sites. However, in both groups, disinfection of the angulation knobs (S-4) was less efficient than the others. For the T-1 site, HBV-DNA was detected from all of them, and in 95% (19/20) of T-2. However, HBV-DNA was not detected from T-3 samples. CONCLUSIONS: Electrolyzed acid water is as efficient as glutaraldehyde in eliminating bacteria from patient-used endoscopes. After disinfection procedures using both methods, HBV-DNA was not detected from any endoscopes experimentally contaminated with HBV-positive mixed sera. However, some bacteria may remain on the surface of the endoscopes. Therefore, more careful precleaning of the endoscopes may help achieve high-level disinfection in the clinical setting.

Bacteria↗

PubMed2003

New integration vector using a cellulase gene as a screening marker for Lactobacillus.

The new integration vector for Lactobacillus, pJC4, was developed using the extracellular endoglucanase A gene (celA) of Clostridium thermocellum as a screening marker. pJC4 was transformed into four Lactobacillus species, Lb. johnsonii, Lb. gasseri, Lb. bulgaricus, and Lb. plantarum. In each species, the pJC4 integrants were easily and accurately detected by the appearance of a clear halo on a cellulase screening plate without any false transformants. Polymerase chain reaction and Southern hybridization indicated that all transformants with clear halos contained pJC4 in their chromosomal DNAs. The celA gene could be a useful screening marker for other lactic acid bacteria.

Cellulase↗

PubMed2003

[Clinical characteristics of colonic diverticulitis in Koreans].

BACKGROUND/AIMS: In western countries, symptomatic diverticulitis develops in about 20% of the population with colonic diverticula, and it is mainly located at the left-sided colon. The clinical characteristics of diverticulitis have rarely been investigated although its incidence is increasing in Asia including Korea. The aim of this study was to compare diverticulitis with asymptomatic diverticulosis and to compare the clinical characteristics of right-sided diverticulitis with those of left-sided diverticulitis. METHODS: We retrospectively investigated the medical records of the patients who had symptoms and signs of diverticulitis. Their diagnosis was confirmed with computed tomography, barium study, colonoscopy and/or operations at Samsung Medical Center from September 1998 to February 2002. The control cases of asymptomatic and incidental diverticulosis were randomly selected during routine health check-up after matching age and sex. RESULTS: Twenty-seven patients with diverticulitis (male : female = 14 : 13) were included. The mean age was 53 (27~86). The ratio of right and left diverticulitis was 20:7, which was similar to the ratio of diverticulosis. The complications, especially perforation, were more frequent in the patients with left-sided diverticulitis (p<0.05). CONCLUSIONS: Colonic diverticulitis is more prevalent at the right colon and left colonic diverticulitis has more complications than right colonic diverticulitis in Korea.

Adult↗

PubMed2003

[A case of serous cystadenoma of the pancreas communicating with the pancreatic duct].

Serous cystadenoma of the pancreas is a rare disease and is usually benign. Mucinous cystadenoma, another cystic neoplasm of the pancreas, has a malignant potential. Serous cystadenoma is usually composed of many small cysts lined by small, cuboidal or flattened cells containing abundant glycogen. With the finding of endoscopic retrograde pancreatography, a communication between the cyst and pancreatic duct is observed occasionally in the mucinous cystadenoma, but rarely in the case of serous cystadenoma of the pancreas. We experienced a case of serous cystadenoma of the pancreas that had a communication between a cyst and the pancreatic duct.

Adult↗

PubMed2002

Activity enhancement of Cel5Z from Pectobacterium chrysanthemi PY35 by removing C-terminal region.

The phytopathogenic bacterium Pectobacteium chrysanthemi PY35 secretes Cel5Z endoglucanase belonging to the glycoside hydrolase family 5 of EC 3.2.1.4. The mutation of cel5Z::Omega gene was constructed by cloning the 2.0-kb SmaI fragment containing the streptomycin/spectinomycin-resistance gene of pHP45(Omega) into the BalI site of pPY100. The insertion of Omega fragment generated a new stop codon, removing the Ser/Thr-rich linker region and the cellulose binding domain (CBD) in the C-terminal region of cel5Z gene. By subsequent subcloning from this 4.9-kb fragment (pPY1001), a 1.0-kb (pPY1002) fragment was obtained and designated as cel5Z::Omega. The cel5Z::Omega gene had an open reading frame (ORF) of 1011 bp, encoding 336 amino acids, starting with an ATG codon and ending with a new TGA stop codon. The molecular mass of the Cel5Z::Omega protein in E. coli transformant appeared to be 32 kDa by SDS-PAGE analysis in the presence of carboxymethyl-cellulose (CMC). The Cel5Z::Omega protein hydrolyzed CMC with 1.7-fold higher activity than the intact Cel5Z cellulase.

Amino Acid Sequence↗