Biomedical subjects

Hong Kim

Publications and source records attributed to Hong Kim.

At least 19 recordsLinked to original sources

PubMed2007

Atorvastatin preserves renal function in chronic complete unilateral ureteral obstruction.

PURPOSE: The pleiotropic effects of hMG-CoA (3-hydroxy-3-metylglutaryl coenzyme A) reductase inhibitors may provide renal protection in chronic kidney disease. We examined whether atorvastatin administration preserved renal function in rats with chronic unilateral ureteral obstruction. MATERIALS AND METHODS: Renal clearance experiments were performed in sham operated rats and rats subjected to 3 or 12-day unilateral ureteral obstruction. Hemodynamics parameters and urinary microalbumin levels from the obstructed kidney were also measured. The rats were maintained on a regular diet or the same diet but supplemented with atorvastatin (50 mg/kg daily). RESULTS: Atorvastatin administration did not alter plasma total cholesterol but it significantly decreased triglyceride levels. In sham operated and 3-day unilateral ureteral obstruction rats atorvastatin treatment did not have effects on the glomerular filtration rate or effective renal plasma flow and it also did not affect urinary microalbumin levels. In rats with 12-day unilateral ureteral obstruction the glomerular filtration rate but not effective renal plasma flow was significantly higher and urinary microalbumin was significantly lower in atorvastatin treated rats than in those without atorvastatin treatment. CONCLUSIONS: Atorvastatin treatment decreased microalbuminuria and helped preserve filtration function in chronic unilateral ureteral obstruction without altering plasma cholesterol levels, suggesting that pleiotropic renal protection is offered by this statin.

Animals↗

PubMed2006

Molecular epidemiology of hepatitis B virus (HBV) genotypes and serotypes in patients with chronic HBV infection in Korea.

OBJECTIVES: Although hepatitis B virus (HBV) is endemic to Korea, no large-scale survey of HBV genotypes and serotypes based on sequence analysis has been performed. METHODS: In the present study, we genotyped and serotyped HBV strains from 209 patients in two Korean regions, Seoul (107 patients) and Jeju (102 patients), an island off the southeastern Korean coast. Analyses were conducted using the direct sequencing method targeting the partial surface (S) gene (541 bp). RESULTS: Phylogenetic analysis showed that all HBV strains from the 209 patients belonged to genotype C2 (100%). Of the 209 patients, 193 (92.3%), 12 (5.7%) and 1 (0.5%) were found to have the adr, adw and ayr serotypes, respectively. The other three strains (1.5%) showed unique serotype and were not typeable by sequence analysis. No HBV strains characteristic of Jeju island were observed. CONCLUSIONS: The extraordinary predominance of genotype C2 in chronic Korean patients, which is known to be associated with more severe liver disease than genotype B, suggests that the clinical manifestations of Korean HBV chronic patients are likely to differ from those found in other Asian countries, especially in Japan and Taiwan, where genotypes B and C coexist.

Adult↗

PubMed2006

Multidimensional learning curve in laparoscopy-assisted gastrectomy for early gastric cancer.

BACKGROUND: Laparoscopy-assisted gastrectomy (LAG) is a complex and time-consuming procedure, which is increasingly used for early gastric cancer (EGC). We provide a multidimensional analysis of the learning curve in LAG. METHODS: Cumulative sum method was used to analyze outcomes of 109 patients undergoing LAG for EGC by one surgeon over a two year period; the influence of patient selection was evaluated. Target failure rate was set at 10%, with failure defined as open conversion, mortality, major morbidity, residual tumor, or inappropriate lymphadenectomy. RESULTS: There were 19 failures--fourteen performance and five oncologic. The learning curve, which displayed a slight rising trend and three phases was achieved after 40 cases with selected patients; it was broken, however, by the introduction of advanced procedures and unselected patients. CONCLUSIONS: Advanced procedures and broad indications in LAG should be delayed until a learning curve is completed under the target failure rate.

Adult↗

PubMed2006

Differentiation of Mycobacterial species by hsp65 duplex PCR followed by duplex-PCR-based restriction analysis and direct sequencing.

Here we describe a novel duplex PCR method which can differentiate Mycobacterium tuberculosis and nontuberculosis mycobacteria (NTM) strains by amplifying hsp65 DNAs of different sizes (195 and 515 bp, respectively). The devised technique was applied to 54 reference and 170 clinical isolates and differentiated all strains into their respective groups with 100% sensitivity and specificity. Furthermore, a duplex PCR-restriction analysis (duplex PRA) and a direct sequencing protocol were developed to differentiate NTM strains at the species and subspecies levels based on previously reported hsp65 DNA sequences (H. Kim et al., Int. J. Syst. Evol. Microbiol. 55:1649-1656, 2005) and then applied to 105 NTM clinical isolates. All NTM isolates were clearly differentiated at the species and subspecies levels by subsequent procedures (PRA or direct sequencing) targeting 515-bp NTM duplex PCR amplicons. Our results suggest that novel duplex PCR-based methods are sensitive and specific for identifying mycobacterial culture isolates at the species level.

Bacterial Proteins↗

PubMed2006

Adaptive responses induced by low dose radiation in dentate gyrus of rats.

The purpose of this study is to investigate the mechanism of alternative responses to low dose irradiation for neuronal cell proliferation in the dentate gyrus of rats. To determine the effect of a single exposure to radiation, rats were irradiated with a single dose of 0.1, 1, 10 or 20 Gy. To determine the effect of the cumulative dose, the animals were irradiated daily with 0.01 Gy or 0.1 Gy from 1 to 4 days. The neuronal cell proliferation was evaluated using immunohistochemistry for 5-bromo-2'-deoxyuridine (BrdU), Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) staining. Four consecutive daily irradiations with a 0.01 Gy/fraction increased the number of BrdU-positive and Ki-67-positive cells in a dose dependent manner, but this did not affect the number of TUNEL-positive cells. However, there was not a dose dependent relationship for the 0.1 Gy/fraction irradiation with the number of BrdU, Ki-67 and TUNEL positive cells. Our data support the explanation that the adaptive response, induced by low-dose radiation, in the hippocampus of rats is more likely a reflection of the perturbations of cell cycle progression.

Adaptation, Physiological↗

PubMed2005

Maternal swimming during pregnancy enhances short-term memory and neurogenesis in the hippocampus of rat pups.

In the present study, the effects of maternal swimming during pregnancy on the short-term memory ability, hippocampal neurogenesis, and brain-derived neurotrophic factor (BDNF) mRNA expression of rat pups were investigated. After confirming their pregnancy, the pregnant rats were divided into two groups: the control group and the swimming group. From the 15th day of pregnancy until delivery, pregnant rats were subcutaneously injected with 100mg/kg of 5-bromo-2'-deoxyuridine (BrdU) once a day at 30min before the starting of swimming exercise. Pregnant rats in the swimming group were forced to swim for 10min once a day until delivery. On the 21 days after birth, the rat pups were trained in a step-down avoidance test. The latency time of the step-down avoidance task was determined on the 28 days after birth in order to evaluate the short-term memory ability of pups. On the 29 days after birth, the rat pups' brains were removed, and BrdU immunohistochemistry for the detection of neurogenesis and reverse transcription-polymerase chain reaction (RT-PCR) for the detection of BDNF mRNA expression were then performed. The rat pups born from the maternal rats that performed swimming during pregnancy showed significantly increased BDNF mRNA expression, enhanced hippocampal neurogenesis, and improved short-term memory capability. The present results have clearly shown that maternal swimming by rats during pregnancy enhances the memory of the rats' offspring by increasing neurogenesis. Our present study provides the evidence that maternal exercise during the gestational period may enhance the brain functions of the mothers' offspring.

Aging↗

PubMed2005

Assessment of BNP and NT-proBNP in emergency department patients presenting with suspected acute coronary syndromes.

OBJECTIVES: The relationship between BNP and NT-proBNP among physiologically and clinically relevant demographic subgroups has never been clarified in the context of the emergency department (ED). DESIGN AND METHODS: A blood sample taken from patients presenting to the E.D. with suspected acute coronary syndromes (ACS) was analyzed for BNP and NT-proBNP, and correlation between them was examined as an entire group then as subgroups according to gender, ethnicity, age, and comorbidity variables. RESULTS: BNP and NT-proBNP correlate well (0.89, P < 0.0001) in a population of 420 patients and in patient subgroups with a history of various etiologies, including vascular disorders. CONCLUSIONS: In general, BNP and NT-proBNP correlate very well in patients with suspected ACS and may aid in the risk stratification process in emergency departments.

Acute Disease↗

PubMed2005

Influence of prenatal noise and music on the spatial memory and neurogenesis in the hippocampus of developing rats.

During the prenatal period, the development of individual is influenced by the environmental factors. In the present study, the influence of prenatal noise and music on the spatial memory and neurogenesis in the hippocampus of developing rats was investigated. The exposure to the noise during pregnancy caused growth retardation, decreased neurogenesis in the hippocampus, and impaired spatial learning ability in pups. The exposure to music during pregnancy, on the other hand, caused increased neurogenesis in the hippocampus and enhanced spatial learning ability in pups. The present study has shown the importance of the prenatal environmental conditions for the cognition and brain development.

Animals↗

PubMed2005

Maternal alcohol administration suppresses expression of nitric oxide synthase in the hippocampus of offspring rats.

Maternal alcohol consumption during pregnancy can produce teratogenic effects and has a detrimental effect on the development of the fetus. In this study, the dose-dependent effect of maternal alcohol administration on the expression of nitric oxide synthase (NOS) in the hippocampus of the offspring rats was investigated. From the present result, it was shown that expression of NOS is decreased following treatment with maternal alcohol in a dose-dependent fashion. The present results suggest that suppression of NOS expression in the hippocampus of offspring rats with maternal alcohol mediates the associated developmental retardation and/or anomalies.

Actins↗

PubMed2005

Influence of maternal alcohol administration on c-Fos expression in the hippocampus of infant rats.

Maternal alcohol consumption during pregnancy is known to have a detrimental effect on the development of the fetus and its central nervous system (CNS) in particular. In the present study, the dose-dependence of the effect of maternal alcohol on hippocampal c-Fos expression, which is a marker of hippocampal neuronal activity and which is induced by a variety of stimuli, was examined in infant rats. In the present study, it was shown that expression of c-Fos in the hippocampus is decreased following treatment with alcohol in a dose-dependent fashion. Based on the results of the present study and the findings of other studies, it can be suggested that suppression of c-Fos expression in the hippocampus of infant rats with maternal alcohol administration mediates the associated developmental retardation and/or anomalies.

Animals↗

PubMed2005

Amylase level in extrahepatic bile duct in adult patients with choledochal cyst plus anomalous pancreatico-biliary ductal union.

AIM: To investigate the relationship between pancreatic amylase in bile duct and the clinico-pathological features in adult patients with choledochal cyst and anomalous pancreatico-biliary ductal union (APBDU). METHODS: From 39 patients who underwent surgery for choledochal cyst between March 1995 and March 2003, we selected 15 adult patients who had some symptoms and were radiologically diagnosed as APBDU, and their clinico-pathological features were subsequently evaluated retrospectively. However, we could not obtain biliary amylase in all the patients because of the surgeon's slip. Therefore, we measured the amylase level in gall bladder of 10 patients and in common bile duct of 11 patients. RESULTS: Levels of amylase in common bile duct and gall bladder ranged from 11,500 to 212,000 IU/L, and the younger the patients, the higher the biliary amylase level (r = -0.982, P<0.01). Pathologically, significant correlation was found between the size of choledochal cyst and the grade of inflammation (r = 0.798, P<0.01). And, significant correlation was found between the level of amylase in gall bladder and the grade of hyperplasia. On the other hand, there was no correlation to the age of symptomatic onset or inflammatory grade (r = 0.743, P<0.05). Level of lipase was elevated from 6,000 to 159,000 IU/L in bile duct and from 14,400 to 117,000 IU/L in the gall bladder; however, there was no significant correlation with age or clinico-pathological features. CONCLUSION: The results support the notion that amylase has a particular role in the onset of symptoms, and suggest that a large amount of biliary amylase induces early onset of symptom, thereby making early diagnosis possible.

Adult↗

PubMed2005

Long-term treadmill exercise overcomes ischemia-induced apoptotic neuronal cell death in gerbils.

It has been suggested that exercise may ameliorate neurologic impairment by impeding neuronal loss following various brain insults. In the present study, the effect of long-term treadmill exercise on short-term memory and apoptotic neuronal cell death in the hippocampus following transient global ischemia in gerbils was investigated. A step-down inhibitory avoidance task, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay, and immunohistochemistry for caspase-3 were used for this study. Ischemia was induced by occlusion of both the common carotid arteries of gerbils for 5 min. Gerbils in the exercise groups were forced to run on a treadmill for 30 min once a day for 4 consecutive weeks. The present results reveal that treadmill exercise for 4 weeks improved short-term memory by suppressing the ischemia-induced apoptotic neuronal cell death in the hippocampus. Here in this study, we show that long-term treadmill exercise for 4 weeks overcomes the ischemia-induced apoptotic neuronal cell death and thus facilitates the recovery of short-term memory impairment induced by ischemic cerebral injury.

Animals↗

PubMed2005

Maternal ethanol administration inhibits 5-hydroxytryptamine synthesis and tryptophan hydroxylase expression in the dorsal raphe of rat offspring.

Maternal ethanol consumption during pregnancy has a detrimental effect on the central nervous system (CNS) development of fetus. 5-Hydroxytryptamine (5-HT) is an important neurotransmitter and/or neuromodulator in the mammalian CNS. Tryptophan hydroxylase (TPH) is the rate limiting enzyme of 5-HT synthesis. Ethanol is known to induce neuropsychiatric disorders by alteration of the central serotonergic system. In the present study, the effects of maternal ethanol intake on the 5-HT synthesis and the TPH expression in the dorsal raphe of rat offspring were investigated. The present results show that the synthesis of 5-HT and the expression of TPH in the dorsal raphe of rat offspring were suppressed by maternal ethanol intake and that the suppressive effect of alcohol was more potent in the 5 weeks old rat pups compared to the 3 weeks old rat pups. Based on the present study, it can be suggested that the pathogenesis of ethanol-induced neuropsychological disorders involves ethanol-induced suppression on the 5-HT synthesis and the TPH expression in the dorsal raphe of offspring.

Animals↗

PubMed2005

Comparison of full length sequences of hepatitis B virus isolates in hepatocellular carcinoma patients and asymptomatic carriers of Korea.

Relatively few genomic sequences of Korean hepatitis B virus (HBV) isolates are available. Moreover, no comparative study has been made between the full-length genomes of Korean HBV isolates and clinical status. To evaluate mutations in HBV isolates obtained from chronically infected HBV patients in terms of clinical significance, we determined the genomic sequences of HBV isolates obtained from three hepatocellular carcinoma (HCC) patients (He52, He53, and He82) and from three asymptomatic carriers (He74, He100, and He127). A comparison of sequence variations showed that the HBV isolates from the three HCC patients showed higher frequencies of mutation than the isolates from the three asymptomatic carriers. Three characteristic mutation patterns were identified in the HBV isolates from the HCC patients, which distinguished the HBV isolates from the asymptomatic carriers. First, HBV isolates from the three HCC patients both had double mutations in a core promoter (T1762/A1764) and a precore mutation (A1896). Second, although these isolates belonged to genotype C, 11 amino acids deletions in the preS1 region, specific for HBV genotype D, were detected in the isolates of two HCC patients (He52 and He82). Third, mutations (I127T/N, K130M, and V131I) at three codons in the carboxy functional region of X protein were observed in isolates from all three HCC patients. Additionally, phylogenetic analysis based on the entire HBV sequences showed that all six isolates belonged to genotype C2, as do other Korean strains.

Adult↗

PubMed2005

Prevalence of naturally occurring surface antigen variants of hepatitis B virus in Korean patients infected chronically.

Although Korea is one of the endemic areas of hepatitis B virus (HBV) infection, the prevalence of naturally occurring variants in the major hydrophilic region (MHR) of the surface (S) gene of HBV has not been determined. In the present study, the prevalence of these variants was examined in terms of the clinical state, and HBeAg serostatus in a large series of Korean patients with chronic HBV infection by direct sequencing analysis of part of the S gene containing the MHR of HBV isolated from 101 chronic HBV patients (51 HBeAg-positive and 50 HBeAg-negative): 37 were asymptomatic carriers, 21 had chronic hepatitis, 20 had liver cirrhosis, and 23 had hepatocellular carcinoma (HCC). Forty-seven MHR variants (46.5%) of the 101 patients were detected, involving a total of 59 amino acid substitutions at 12 positions inside and 14 position outside the 'a' determinant, and 33 'a' determinant variants (32.7%). A total of 17 novel variants and 14 novel mutation patterns were detected. The prevalence of MHR variants in HBeAg-negative patients tended to be higher than in HBeAg-positive patients (54.0% vs.39.2%) and the prevalence of MHR variants in HCC and liver cirrhosis tended to be higher than in asymptomatic carriers (65.2% vs. 40.5% and 50.0% vs. 40.5%, respectively). In conclusion, three important findings were found in the present study. First, an unexpectedly high prevalence of naturally occurring MHR variants was found in Korean chronic patients. Second, several novel variants associated with mutations outside the 'a' determinant were detected. Finally, a higher prevalence of MHR variants was associated with HBeAg-negative serostatus and severe liver disease, particularly HCC.

Adolescent↗

PubMed2005

PCR restriction fragment length polymorphism analysis (PRA)-algorithm targeting 644 bp Heat Shock Protein 65 (hsp65) gene for differentiation of Mycobacterium spp.

A method based on PCR-restriction fragment length polymorphism analysis (PRA) using a novel region of the hsp65 gene was developed for the rapid and exact identification of mycobacteria to the species level. A 644 bp region of hsp65 in 62 mycobacteria reference strains, and 4 related bacterial strains were amplified, and the amplified DNAs were subsequently digested with restriction enzymes, namely, AvaII, HphI, and HpaII. Most of the mycobacteria species were easily differentiated at the species level by the developed method. In particular, the method enabled the separation of M. avium, M. intracellulare and M. tuberculosis to the species level by AvaII digestion alone. An algorithm was constructed based on the results and a blind test was successfully performed on 251 clinical isolates, which had been characterized by conventional biochemical testing. Our results suggest that this novel PRA offers a simple, rapid, and accurate method for the identification of mycobacteria culture isolates at the species level.

Algorithms↗

PubMed2005

Mechanism of natural rifampin resistance of Streptomyces spp.

In a previous phylogenetic study of the genus Streptomyces using the rpoB gene, N531, which stands for an aspargine residue in position 531 of RpoB instead of serine (S531), known to be associated with natural rifampin resistance in several organisms, was also observed in the RpoB of several Streptomyces species. To determine whether N531 is associated with the rifampin resistance of Streptomyces strains, we analyzed the rifampin minimum inhibitory concentrations (MICs) of 11 strains of the N531 RpoB type (putative rifampin resistant strains) and of 12 strains of the S531 RpoB type. (putative rifampin susceptible strains). In general, the N531 RpoB types showed higher MIC levels (16-128 microg/ml) than the S531 RpoB types (0-8 microg/ml). To determine the isolation frequencies of N531 RpoB types versus rifampin concentration, we applied screening methods involving different rifampin concentrations (0, 20 and 100 microg/ml) to Korean soils. Higher isolation frequencies of the N531 RpoB types were observed at the higher rifampin concentrations. In addition, during the course of this study we developed an allele specific PCR method to detect rifampin resistant Streptomyces strains. Our results strongly suggested that N531 might be involved in a major mechanism of natural rifampin resistance in strains of the genus Streptomyces.

Amino Acid Sequence↗

PubMed2005

Renal responses to atrial natriuretic peptide are preserved in bilateral ureteral obstruction and augmented by neutral endopeptidase inhibition.

PURPOSE: Atrial natriuretic peptide (ANP) contributes to post-obstructive diuresis in bilateral ureteral obstruction (BUO). In this study we examined the activity of neutral endopeptidase (NEP), an enzyme responsible for degradation of ANP, in the kidney in rats subjected to BUO for 24 hours. MATERIALS AND METHODS: Renal function was examined by the clearance method in sham operated rats and BUO rats after obstruction release. Renal responses to an intravenous bolus injection of ANP (5 microg/kg) were studied in sham operated and BUO rats with or without pretreatment with intravenous phosphoramidon (100 microg/kg per minute), a NEP inhibitor. RESULTS: In BUO rats natriuresis and diuresis occurred despite a marked decrease in the glomerular filtration rate (GFR). ANP administration increased GFR and induced marked natriuresis and diuresis in sham operated and BUO rats. Inhibition of ANP degradation by phosphoramidon induced natriuresis and diuresis, and accentuated these renal responses to ANP. CONCLUSIONS: Renal responses to ANP and renal NEP activity were preserved in 24-hour BUO. NEP inhibition to attenuate ANP degradation augmented responses to ANP in increasing GFR, natriuresis and diuresis. These findings provide the theoretical potential for facilitating the recovery of GFR after BUO release by inhibiting ANP degradation by pharmacological means.

Animals↗