Biomedical subjects

N Kim

Publications and source records attributed to N Kim.

At least 55 records · Page 3Linked to original sources

PubMed2000

Long-term effects of Helicobacter pylori eradication on intestinal metaplasia in patients with duodenal and benign gastric ulcers.

This study was conducted to investigate whether or not the eradication of H. pylori could lead to the regression of intestinal metaplasia (IM) in patients with either duodenal ulcer (DU) or benign gastric ulcer (BGU). The initial antral IM grade was 0.21 in the 72 patients of the H. pylori-eradicated DU group, this decreased to 0.17, 0.14, 0.13, and 0.09 after periods of four weeks, one year, two years, and four years, respectively, but without statistical significance. In the corpus of the DU group, where IM grade was low (0.02), there was no detectable change in IM. The initial antral IM grade of 0.69 in the 41 patients of the H. pylori-eradicated BGU group decreased substantially to 0.61, 0.44, and 0.39 after periods of four weeks and one and two years, respectively, but again without statistical significance. The initial corporal IM grade of the BGU group of 0.27 decreased to 0.20, 0.15, and 0.06 after periods of four weeks and one and two years, again without statistical significance. In contrast, the IM grades of the noneradicated DU group (N = 20) and the BGU group (N = 16) showed nearly no change in the antrum and corpus. Gastritis grades of antrum and corpus in the H. pylori-eradicated DU or BGU group significantly decreased with respect to time (P = 0.0001), but there were no significant changes in the corresponding noneradicated groups. Although there was no statistical significance, IM decreased in the antrum and corpus of the stomach with BGU and in antrum of those with DU over a two to four-year period after H. pylori eradication, suggesting the possible reversibility of IM.

Adolescent↗

PubMed2000

Evaluation of a human bio-engineered skin equivalent for drug permeation studies.

PURPOSE: To test the barrier function of a bio-engineered human skin (BHS) using three model drugs (caffeine, hydrocortisone, and tamoxifen) in vitro. To investigate the lipid composition and microscopic structure of the BHS. METHODS: The human skin substitute was composed of both epidermal and dermal layers, the latter having a bovine collagen matrix. The permeability of the BHS to three model drugs was compared to that obtained in other percutaneous testing models (human cadaver skin, hairless mouse skin, and EpiDerm). Lipid analysis of the BHS was performed by high performance thin layered chromatography. Histological evaluation of the BHS was performed using routine H&E staining. RESULTS: The BHS mimicked human skin in terms of lipid composition, gross ultrastructure, and the formation of a stratum corneum. However, the permeability of the BHS to caffeine, hydrocortisone, and tamoxifen was 3-4 fold higher than that of human cadaver skin. CONCLUSIONS: In summary, the results indicate that the BHS may be an acceptable in vitro model for drug permeability testing.

Animals↗

PubMed2000

Cripto-1 induces apoptosis in HC-11 mouse mammary epithelial cells.

Cripto-1 (CR-1) is an epidermal growth factor (EGF)-related protein. CR-1 can inhibit beta-casein and whey acidic protein expression in mouse mammary epithelial cells. The present study demonstrates that CR-1 can induce apoptosis in HC-11 mouse mammary epithelial cells, as measured by bis-benzimide stained nuclei, TUNEL assay and cell death ELISA. Apoptosis could be observed after 2 days of exposure of confluent HC-11 cells to CR-1 in the absence of the survival factors EGF and insulin, with maximum apoptosis occurring at 3 days. A reduction in poly(ADP-ribose) polymerase (PARP) expression and an increase in beta-catenin cleavage was found after 18 h of exposure to CR-1 suggesting that apoptosis was preceded by the induction of a caspase activity since the caspase inhibitor ZFAD.FMK could block the CR-1-induced reduction in PARP expression and CR-1-induced apoptosis. CR-1 was found to increase the expression of caspase-3-like protease. Although, the levels of p27kip1 and p21Bax did not change after exposure to CR-1 for 18 h, the levels of Bcl-xL became undetectable. These studies suggest that CR-1 promotes apoptosis by mediating the induction of caspase-3-like protease and downregulating the expression of Bcl-xL.

Animals↗

PubMed2000

Multi-valvular endocarditis.

OBJECTIVE: Seventy-seven cases of native valve infective endocarditis as determined by the Duke criteria, were reviewed to determine the incidence and clinical features of multi-valvular endocarditis. METHODS: Fourteen of 77 patients (18%) had multi-valvular endocarditis most commonly involving the mitral and aortic valves. Staphylococcus aureus (43%) and viridans streptococci (36%) were the most common organisms causing multi-valvular endocarditis. RESULTS: Definite or probable vegetations were found in 50% of the patients by two-dimensional transthoracic echocardiograph and/or transesophageal echocardiograph, and possible vegetations were detected in 21%. The overall mortality in our series was 21%; 29% underwent valve replacement and 50% were treated medically. The major complications of multi-valvular endocarditis were congestive heart failure (64%), acute renal failure (50%), embolic events (21%), and splenic abscess/infarcts (21%). CONCLUSIONS: Our data suggests complications of multi-valvular endocarditis, compared with uni-valvular endocarditis are similar except for heart failure. Heart failure is statistically more common in multi-valvular endocarditis (P < or = 0.002).

Acute Kidney Injury↗

PubMed2000

Prevention of thromboembolism in atrial fibrillation. A meta-analysis of trials of anticoagulants and antiplatelet drugs.

OBJECTIVE: Appropriate use of drugs to prevent thromboembolism in patients with atrial fibrillation (AF) involves comparing the patient's risk of stroke and risk of hemorrhage. This review summarizes the evidence regarding the efficacy of these medications. METHODS: We conducted a meta-analysis of randomized controlled trials of drugs used to prevent thromboembolism in adults with nonpostoperative AF. Articles were identified through the Cochrane Collaboration's CENTRAL database and MEDLINE until May 1998. MAIN RESULTS: Eleven articles met criteria for inclusion in this review. Warfarin was more efficacious than placebo for primary stroke prevention (aggregate odds ratio [OR] of stroke = 0.30, 95% confidence interval [CI] 0.19, 0.48), with moderate evidence of more major bleeding (OR 1.90; 95% CI 0.89, 4.04). Aspirin was inconclusively more efficacious than placebo for stroke prevention (OR 0.56, 95% CI 0.19, 1.65), with inconclusive evidence regarding more major bleeds (OR 0.81, 95% CI 0.37, 1.77). For primary prevention, assuming a baseline risk of 45 strokes per 1,000 patient-years, warfarin could prevent 30 strokes at the expense of only 6 additional major bleeds. Aspirin could prevent 17 strokes, without increasing major hemorrhage. In direct comparison, there was evidence suggesting fewer strokes among patients on warfarin than among patients on aspirin (aggregate OR 0.64, 95% CI 0.43, 0.96), with only suggestive evidence for more major hemorrhage (OR 1.60, 95% CI 0.77,3.35). However, in younger patients, with a mean age of 65 years, the absolute reduction in stroke rate with warfarin compared with aspirin was low (5.5 per 1,000 person-years) compared with an older group (15 per 1,000 person-years). CONCLUSION: In general, the evidence strongly supports warfarin for patients with AF at average or greater risk of stroke. Aspirin may prove to be useful in subgroups with a low risk of stroke, although this is not definitively supported by the evidence.

Anticoagulants↗

PubMed2000

Transsphenoidal supradiaphragmatic intradural approach: technical note.

Presellar extension of the bone window combined with removal of the sellar floor results in the transsphenoidal supradiaphragmatic intradural approach. One tuberculum sella meningioma and another suprasellar Rathke's cleft cyst confined to the pituitary stalk were removed via this approach. The presellar extension of the bone window was performed with the sublabial transseptal transsphenoidal technique. Furthermore, the dissection of the anterior intercavernous sinus, diaphragma sella, and arachnoid trabecula has allowed a wide surgical field of pre- and suprasellar areas and facilitates safe removal of lesions without significant surgical complications in selected cases.

Adult↗

PubMed2000

Epidemiology of chronic bronchitis and acute infective exacerbations of chronic bronchitis.

Acute exacerbations of chronic bronchitis (AECBs) are one of the major causes of morbidity and mortality in the United States, resulting in significant cost to the health care system. Epidemiological information on chronic bronchitis is abundant and has been collected in most industrialized countries. The epidemiology of AECB, however, is less forthcoming. The causes of AECB are multifactorial and include environmental pollutants, allergic responses, and viral and bacterial infections. The role of bacterial infection in AECB is controversial but is believed to account for half of AECB. Because the medical and economic implications of treatment failure in these patients are substantial, an aggressive approach to stratify and treat these patients is necessary. Epidemiological data on chronic bronchitis and acute infective exacerbations of chronic bronchitis will allow us to more precisely define the role of bacterial infection in AECB, and this information may help guide antimicrobial therapy.

Journal Article↗

PubMed2000

Immunohistochemical localization of telomerase hTERT protein and analysis of clonality in multifocal vulvar intraepithelial neoplasia.

Vulvar intraepithelial neoplasias (VINs) are potentially premalignant lesions of the squamous mucosa. The immunohistochemical distribution of the catalytic protein subunit of telomerase (hTERT) and the patterns of X chromosome inactivation were investigated as markers of neoplasia in samples from a patient with multifocal and diffuse VIN. hTERT nuclear staining in VIN correlated with squamous maturation and the degree of nuclear atypia. Normal mucosa revealed faint nuclear staining of parabasal cells and lower intermediate layer squamous cells. Monoclonal composition was demonstrated in 0 of 3 samples of VIN1, 2 of 3 samples of VIN2, and 13 of 13 samples of VIN3. The patterns of X chromosome inactivation indicated intramucosal extension and multifocal origin of individual lesions. Five samples of histologically normal vulvar squamous epithelium revealed a random pattern of X chromosome inactivation, consistent with polyclonal composition. All 19 samples from 9 lesions contained human papillomavirus (HPV)-16 sequences. Neither mutations in the p53 tumor suppressor gene or K-ras oncogenes nor loss of heterozygosity at 7 chromosomal loci were detected in any of the 19 samples of VIN. These results demonstrate that HPV-associated VIN may result from multifocal and diffuse 2-dimensional intraepithelial expansion of an immortalized monoclonal cell population.

Carcinoma in Situ↗

PubMed2000

High-performance liquid chromatographic analysis of saponin compounds in Bupleurum falcatum.

A mixture of saponin compounds (saikosaponin c, a, and d) in the 70% ethanol extract of a powdered sample of Bupleuri radix are analyzed by an Inertsil ODS-3 C(18) column at a flow rate of 1.0 mL/min and detection wavelength of 203 nm. Well resolved chromatograms of saikosaponin c, a, and d are obtained with a gradient elution of acetonitrile-water from 40:60 (v/v) to 50:50 (v/v). The total time required for a single analysis is approximately 20 min. Calibration curves for saikosaponin c, a, and d are linear up to 2.5 mg/mL. The coefficient of variability values for saikosaponins in the extract are below 4%, and the recoveries for saikosaponin c, a, and d are 95.2 +/- 1.1, 96.5 +/- 0.9, and 96.2 +/- 1.0%, respectively. The changes in saikosaponin contents for a two-year growth of Bupleurum falcatum are measured by the established high-performance liquid chromatography method.

Chromatography, High Pressure Liquid↗

PubMed2000

The TATA binding protein, c-Myc and survivin genes are not somatically hypermutated, while Ig and BCL6 genes are hypermutated in human memory B cells.

Immunoglobulin (IG:) genes are hypermutated in mature B cells after interaction with antigen and T cells in a germinal center reaction. We and others have recently shown that the human BCL6 gene is also hypermutated in human peripheral blood memory B cells and tonsils. A preliminary analysis of other non-Ig genes (c-MYC:, S14 and AFP) suggested that they were not mutated in memory B cells. We have now performed an in-depth analysis of three non-Ig genes that are expressed in germinal center B cells in two human donors in whom BCL6 is highly mutated. It was found that the TATA binding protein (TBP), c-MYC: and survivin genes are not hypermutated. This lack of targeting by the Ig hypermutation mechanism must be due to the lack of regulatory DNA elements, since the primary sequences of the three tested genes have at least as high intrinsic mutability indices as the BCL6 gene.

B-Lymphocytes↗

PubMed2000

Proto-oncogene Raf-1 as an autoantigen in Meniere's disease.

The 28 kd protein extracted from the guinea pig inner ear membranous fraction, which reacted with sera from patients with Meniere's disease, has been subjected to microsequencing. Nineteen amino acids were obtained (IVQQFGFQRRASDDGKLTQ). A protein data bank search showed that this sequence corresponded to residues 41 to 60 of human Raf-1 protein. Sera from 16 of 27 patients with Meniere's disease showed reactivity to the recombinant purified glutathione-S-transferase-Raf-1 protein. These results support the hypothesis that a subgroup of patients who suffer from Meniere's disease, as well as some other kinds of autoimmune inner ear diseases, have an autoantibody against Raf-1 protein.

Amino Acid Sequence↗

PubMed2000

The frequency of mutation in CCR5 gene among Koreans.

To better understand a role of the delta32 allele of the CCR5 gene in HIV-1 transmission and disease progression, we determined the CCR5 genotypes within several groups of Koreans. Amplification of DNA from each subject was achieved with polymerase chain reaction, using the CCR5 specific primer pair, which flanks the 32 bp deletion. The 1.2 kb coding sequences of CCR5 were examined to see the possible effects of CCR5 polymorphism. All of the 339 healthy, HIV-uninfected individuals had no mutation in the CCR5 gene. All of the 115 HIV-1-infected patients including 11 long-term non-progressors (LTNPs) and 18 discordant spouses were also wild homozygotes. No variation in the 1.2kb CCR5 coding sequence was found in 5 LTNPs and 5 discordant spouses. In conclusion, the 32 bp deletion mutant is rarely present in Koreans. Our data suggest that factors other than the CCR5 coding sequences may also play a role in the resistance to HIV infection.

Alleles↗

PubMed2000

Localization of telomerase hTERT protein and hTR in benign mucosa, dysplasia, and squamous cell carcinoma of the cervix.

Telomerase has been detected by telomerase repeat amplification protocol (TRAP) assay in cervical dysplasia and squamous cell carcinoma but not in most normal cervical tissues. In the present study, the cellular localization of the protein catalytic subunit of telomerase (hTERT) and the RNA component (hTR) were investigated by a sensitive immunohistochemical technique and by in situ hybridization, respectively. hTERT protein was detected in all diagnostic categories of cervical specimens. hTERT was localized predominantly to the lower suprabasal levels of normal squamous mucosa but was detected throughout virtually all levels of the lesional epithelium in low-grade squamous intraepithelial lesions (LSILs), high-grade squamous intraepithelial lesions (HSILs), and squamous cell carcinoma (SCC). Telomerase expression correlated with hTERT detection in SCC and HSIL but was not detected by TRAP assay in most samples of normal mucosa or LSIL. The distribution of hTR correlated with the localization of hTERT in HSIL and SCC but was restricted to the basal and suprabasal cell layers in normal mucosa and LSIL.

Animals↗

PubMed2000

Difference in the distribution pattern of Helicobacter pylori and grade of gastritis in the antrum and in the body between duodenal ulcer and benign gastric ulcer patients.

OBJECTIVES: To investigate the relationship between the Helicobacter pylori (H. pylori) colonization and the grade of gastritis in the antrum and in the body of patients with duodenal ulcer (DU) or benign gastric ulcer (BGU). METHODS: This study was performed in H. pylori-positive 220 DU patients and 180 BGU patients. H. pylori density was evaluated by modified Giemsa staining and CLO test, and gastritis grade was graded by H&E staining in the antrum and in the body. RESULTS: H. pylori grade by Giemsa staining was 1.24 in the antrum and 0.82 in the body for DU group (p < 0.01), and those of BGU group were slightly reversed, 0.83 and 0.87, respectively, but without statistical significance. Similarly H. pylori grade by CLO test was 3.1 in the antrum and 2.8 in the body for DU group (p < 0.01), and those of BGU group 2.3 and 2.6 (p < 0.05), respectively. In contrast, gastritis grade was 1.7 in the antrum and 1.2 in the body for DU group (p < 0.01), and those of BGU group 1.6 and 1.3 (p < 0.01), respectively, similar to those of DU. However, there was a correlation between H. pylori grade and gastritis grade in the antrum and in the body, not only in DU but also in BGU group (p < 0.01). CONCLUSION: In spite of different distribution patterns of H. pylori between DU group and BGU group, gastritis grade of the antrum was significantly higher than that of the body in both DU and BGU. However, gastritis is correlated with H. pylori density not only in DU but also in BGU patients. It looks like the inflammatory reaction to H. pylori is stronger in the antrum than in the body.

Adult↗

PubMed2000

Helicobacter pylori in dental plaque and saliva.

BACKGROUND: About half of the world population is infected with H. pylori, but the transmission and the source of this infection are still unclear. Recently, dental plaque (DP) and saliva have been implicated as possible sources of H. pylori infection. This study was done to investigate the detection rates of H. pylori in the DP and saliva by use of PCR depending on H. pylori infection state of gastric mucosa. METHODS: In 46 subjects, gastric H. pylori colonization was evaluated with CLO test, microscopy of Gram stained mucosal smear, culture and histology after modified Giemsa staining in the antrum and body, respectively. A patient was regarded as H. pylori positive if one or more of the four aforementioned test methods demonstrated H. pylori colonization of the gastric mucosa. For detection of H. pylori in the DP and saliva, PCR assay was done with ET4-U and ET4-L primers. To estimate the sensitivity and specificity of this PCR, H. pylori positivity was evaluated in the antrum and body, separately. RESULTS: The sensitivity of mucosal PCR was 50.0% (27/54) and the specificity 86.8% (33/38). When a subject was regarded as H. pyloi positive, if either antrum or body mucosal H. pylori was is positive, the positive rate of mucosal PCR was 62.1% (18 subjects) in the 29 H. pylori-positive and 17.6% (3 subjects) in the 17 H. pylori-negative subjects. DP PCR was positive in 2 of 29 H. pylori-positive subjects (6.9%) and none in the 17 H. pylori-negative (0%). Saliva PCR was positive in 4 of 14 H. pylori-positive subjects (28.6%) and none of 6 H. pylori-negative (0%). CONCLUSION: The detection rates of H. pylori in DP and saliva by PCR were rather low, 6.9% and 28.6%, respectively, and these rates might have been underestimated by low sensitivity of the PCR method used in this study. However, the results that H. pylori was found in the DP and saliva suggest that the oral cavity can perform a role as a reservoir of H. pylori in Korea.

Dental Plaque↗

PubMed2000

The evidence regarding the drugs used for ventricular rate control.

OBJECTIVE: Our goal was to determine what drugs are most efficacious for controlling the ventricular rate in patients with atrial fibrillation. SEARCH STRATEGY: We conducted a systematic review of the literature published before May 1998, beginning with searches of The Cochrane Collaboration's CENTRAL database and MEDLINE. SELECTION CRITERIA: We included English-language articles describing randomized controlled trials of drugs used for heart rate control in adults with atrial fibrillation. DATA COLLECTION/ANALYSIS: Abstracts of trials were reviewed independently by 2 members of the study team. We reviewed English-language abstracts of non-English-language publications to assess qualitative consistency with our results. MAIN RESULTS: Forty-five articles evaluating 17 drugs met our criteria for review. In the 5 trials of verapamil and 5 of diltiazem, heart rate was reduced significantly (P <.05), both at rest and with exercise, compared with placebo, with equivalent or improved exercise tolerance in 6 of 7 comparisons. In 7 of 12 comparisons of a beta-blocker with placebo, the beta-blocker was efficacious for control of resting heart rate, with evidence that the effect is drug specific, as nadolol and atenolol proved to be most efficacious. All 9 comparisons demonstrated good heart rate control with beta-blockers during exercise, although exercise tolerance was compromised in 3 of 9 comparisons. In 7 of 8 trials, digoxin administered alone slowed the resting heart rate more than placebo, but it did not significantly slow the rate during exercise in 4 studies. The trials evaluating other drugs yielded insufficient evidence to support their use, but those drugs may yet be promising. CONCLUSIONS: The calcium-channel blockers verapamil or diltiazem, or select beta-blockers are efficacious for heart rate control at rest and during exercise for patients with atrial fibrillation without a clinically important decrease in exercise tolerance. Digoxin is useful when rate control during exercise is less a concern.

Adrenergic beta-Antagonists↗

PubMed2000

Characterization and regulation of rat microglial Ca(2+) release-activated Ca(2+) (CRAC) channel by protein kinases.

We measured the activity of the Ca(2+) release-activated Ca(2+) (CRAC) channel present in cultured rat microglia, using the whole-cell mode of patch clamp technique. When the concentration of divalent cations in external solution was reduced to the micromolar range, and Ca(2+) chelating agent BAPTA was included in the pipette solution, we were able to record Na(+) current through CRAC channels in single-channel levels. The unitary Na(+) conductance through CRAC channel was 42.5 pS, which was similar to that of Jurkat cell. The Na(+) current activated slowly, reaching the maximal current level in about 10 min after whole-cell patches were made. The time required for the half-maximal activation of the current was 205 s (+/-31), while it was reduced to 84.3 s (+/-17.7) by including IP(3) in the pipette solution as well. The peak currents ranged from 320 to 985 pA, which corresponded to 64-197 channels per cell. We studied the regulation of the current by protein kinase A (PKA) and protein kinase C (PKC). The current was enhanced by the addition of membrane-permeant analogue of cAMP, dibutyryl cAMP. Pretreating cells with PKA inhibitor, H-89, prevented the effect of dibutyryl cAMP. By contrast, the addition of PKC activator, PDBu, reduced the current. Staurosporine, a PKC inhibitor, prevented the effect of PDBu. These results suggest that CRAC channel in rat microglia is under the regulation of PKA and PKC in opposite directions.

Animals↗

PubMed2000

Efficacy of agents for pharmacologic conversion of atrial fibrillation and subsequent maintenance of sinus rhythm: a meta-analysis of clinical trials.

CONTEXT: Physicians have little evidentiary guidance for pharmacologic agent selection for atrial fibrillation (AF). OBJECTIVE: To assess antiarrhythmic agent efficacy for AF conversion and subsequent maintenance of sinus rhythm (MSR). DATA SOURCE: We searched the clinical trial database of the Cochrane Collaboration and MEDLINE encompassing literature from 1948 to May 1998. STUDY SELECTION: We selected 36 (28%) articles eligible as randomized trials of nonpostoperative AF conversion or MSR in adults. DATA EXTRACTION: Study quality; rates of conversion, MSR, and adverse events were extracted. DATA SYNTHESIS: Compared with control treatment (placebo, verapamil, diltiazem, or digoxin), the odds ratio (OR) for conversion was greatest for ibutilide/dofetilide (OR=29.1; 95% confidence interval [CI], 9.8-86.1) and flecainide (OR=24.7; 95% CI, 9.0-68.3). Less strong but conclusive evidence existed for propafenone (OR=4.6; 95% CI, 2.6-8.2). Quinidine (OR=2.9; 95% CI, 1.2-7.0) had moderate evidence of efficacy for conversion. Disopyramide (OR=7.0; 95% CI, 0.3-153.0) and amiodarone (OR=5.7; 95% CI, 1.0-33.4) had suggestive evidence of efficacy. Sotalol (OR=0.4; 95% CI, 0.0-3.0) had suggestive evidence of negative efficacy. For MSR, strong evidence of efficacy existed for quinidine (OR=4.1; 95% CI, 2.5-6.7), disopyramide (OR=3.4; CI, 1.6-7.1), flecainide (OR=3.1; 95% CI, 1.5-6.2), propafenone (OR=3.7; 95% CI, 2.4-5.7), and sotalol (OR=7.1; 95% CI, 3.8-13.4). The only amiodarone data, from comparison with disopyramide, provided moderate evidence of efficacy for MSR. No trial evaluated procainamide. Direct agent comparisons and adverse event data were limited. CONCLUSIONS: Although multiple antiarrhythmic agents had strong evidence of efficacy compared with control treatment for MSR, ibutilide/dofetilide and flecainide had particularly strong evidence of efficacy compared with control treatment for AF conversion. There is sparse and inconclusive evidence on direct agent comparisons and adverse event rates. Obtaining information regarding these relative efficacies should be a research priority.

Aged↗