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Biomedical subjects

J Park

Publications and source records attributed to J Park.

At least 235 records · Page 13Linked to original sources
PubMed1998

Coexistence of low and high grade squamous intraepithelial lesions of the cervix: morphologic progression or multiple papillomaviruses?

BACKGROUND: The diagnosis of both low (LSIL) and high (HSIL) grade squamous intraepithelial lesions in the same cervical specimen may reflect classification variation, morphologic progression in situ, and, conceivably, different HPV infections. We addressed these possibilities in cervical specimens previously diagnosed as containing both LSIL (condyloma/CIN1) and HSIL (CIN2/3). METHODS: All cases with a histologic diagnosis of LSIL and HSIL from 1994-1996 were reviewed. On review, lesions were scored as (1) no significant variation in lesion grade (classification discrepancies) and showing a (2) one (CIN1-2) or (3) two (CIN1-3) grade shift in the same case. In cases in which a one or two grade shift was confirmed, low (CIN1) and high (CIN2-3) grade foci were microdissected and extracted DNA analyzed for HPV by PCR and RFLP analysis. RESULTS: Of 98 cases available for review, 58 (59%) did not exhibit significant variation in grade (classification discrepancy), and 40 (41%) showed a one (25) or two (15) grade shift. Of the latter group both LSIL and HSIL foci were HPV(+) in 26 (65. 0%). The same HPV was present in both LSIL and HSIL foci in 15/15 lesions with a one grade shift (CIN1-2). In contrast, a significantly higher proportion of lesions with a two grade shift (CIN1-3) contained two different HPV types (4/11 vs 0/15; P = 0.01). Combinations of HPVs in the low/high grade foci, respectively, included HPV 11/16 (1), 11/16 + 18 (1), and HPV39/16 (2). CONCLUSIONS: Lesions containing LSIL and HSIL which span two grades (CIN1 and CIN2) most likely represent morphologic progression in a single infection. Lesions containing CIN1 and CIN 3 may be attributed to both lesion progression and two coincident infections; the latter sometimes present in the same histologic section. The latter phenomenon has implications for both the diagnosis of CIN and interpretation of "morphologic progression" from very low to high grade in the same case.

DNA Primers↗
PubMed1998

Epoxyalkanoyls as novel ACE inhibitors.

The epoxyalkanoyl derivatives were designed and synthesized as ACE inhibitors. Coupling of unsaturated carboxylic acids with amino acids and following epoxidation with dimethyldioxirane gave the epoxyalkanoyls with high yield. The inhibitory activity of synthesized compounds on angiotensin converting enzyme was IC50 values of 0.06-5.5 microM.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Inhibitory effect of lignans from the rhizomes of Coptis japonica var. dissecta on tumor necrosis factor-alpha production in lipopolysaccharide-stimulated RAW264.7 cells.

The inhibitory effect of 10 lignan constituents isolated from the rhizomes of Coptis japonica var. dissecta on tumor necrosis factor (TNF)-alpha production in lipopolysaccharide (LPS)-stimulated macrophage cell line (RAW264.7 cells) has been studied. Among them, pinoresinol, woorenoside-V and lariciresinol glycoside showed significant inhibitory activities in the range from 37% to 55% at the concentration of 25 micrograms/ml. The results are first report that the lignans isolated from Coptis japonica inhibit TNF-alpha production, and suggest that the lignan components may partly participate in antiinflammatory and antiallergic effect of Coptis japonica through the inhibition of TNF-alpha production.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

Cholestasis confers resistance to the rat liver mitochondrial permeability transition.

BACKGROUND & AIMS: Bile salts can cause hepatocyte death by inducing the mitochondrial permeability transition (MPT). However, the slow progression of human cholestatic liver diseases suggests that hepatocytes adapt to resist the MPT. Bcl-x, a protein, and increased mitochondrial cardiolipin, a membrane lipid, elevate the threshold for the MPT. Our aims were to determine if liver mitochondria become resistant to the MPT during cholestasis and, if so, if the resistance is mediated by Bcl-x and/or increased cardiolipin. METHODS: Hepatocytes and liver mitochondria were obtained from bile duct-ligated (BDL) rats and sham-operated rats (control). RESULTS: After addition of glycochenodeoxycholate (GCDC), the magnitude of the MPT was reduced in mitochondria from BDL rats vs. controls. Although Bcl-xL was not increased, mitochondrial cardiolipin content was significantly greater in BDL rats vs. controls. Cell viability was also increased in hepatocytes from BDL rats vs. controls after treatment with GCDC. Feeding BDL rats a fatty acid-deficient diet prevented the increase in mitochondrial cardiolipin content; mitochondria and hepatocytes from these rats were susceptible to the MPT and hepatocellular death by GCDC. CONCLUSIONS: These data suggest that an increase in mitochondria cardiolipin content occurs during cholestasis as an adaptive phenomenon to resist cell death by the MPT.

Animals↗
PubMed1998

A novel type of structurally simple nonpeptide inhibitors for alpha-chymotrypsin. Induced-fit binding of methyl 2-allyl-3-benzenepropanoate to the S2 subsite pocket.

Unexpectedly, methyl and benzyl esters of 2-allyl-3-benzenepropanoic acid were found to be not substrates but potent competitive inhibitors for alpha-chymotrypsin. The inhibitory property of the structurally simple nonpeptidic compounds is ascribed to their high binding affinity to the enzyme at the S2 rather than S1 subsite pocket. These inhibitors exist in a flexible form in solution, but as they bind to the enzyme bulky contrained conformers present in a minute concentration play an important role, forming tighter enzyme.inhibitor complexes by binding to the large hydrophobic S2 pocket. The contrained conformers are thought to be resulted from intramolecular CH/pi interactions between a vinylic proton and the aromatic pi-electron cloud in the inhibitor molecules. These compounds constitute novel examples of the induced-fit binding inhibitor of possibly simplest structure.

Allyl Compounds↗
PubMed1998

Inhibitory effect of sesquiterpene lactones from Saussurea lappa on tumor necrosis factor-alpha production in murine macrophage-like cells.

Total methanol extract of Saussurea lappa radix (Compositae) showed potent inhibitory effect on the production of tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, in murine macrophage-like cell (RAW264.7 cells) in our previous screening studies on 120 Korean medicinal plants. The activity-guided purification of the plant resulted in the isolation of three components. The chemical structures of the components isolated were established by spectroscopic analyses as sesquiterpene lactones [cynaropicrin (1), reynosin (2), and santamarine (3)]. These three compounds inhibited TNF-alpha production in a dose-dependent manner. The molar concentrations of cynaropicrin, reynosin, and santamarine producing 50% inhibition (IC50) of TNF-alpha production were 2.86 micrograms/ml (8.24 microM), 21.7 micrograms/ml (87.4 microM), and 26.2 micrograms/ml (105 microM), respectively. However, treatment with sulphydryl (SH) compounds such as L-cysteine, dithiothreitol, and 2-mercaptoethanol abrogated the inhibitory effect of cynaropicrin on TNF-alpha production. Therefore, we conclude that the principal inhibitory component of Saussurea lappa is cynaropicrin and its inhibitory effect is mediated through conjugation with SH-groups of target proteins.

Animals↗
PubMed1998

Infection with Helicobacter pylori expressing the cagA gene is not associated with an increased risk of developing peptic ulcer diseases in Korean patients.

BACKGROUND: Helicobacter pylori strains possessing the cagA gene have been postulated to have a disease-specific relationship to peptic ulcer. The purpose of this study was to investigate the relationship between the infection with Helicobacter pylori expressing the cagA gene and the development of peptic ulcer diseases in Korean patients. METHODS: Genomic DNA and bacterial mRNA in the gastric mucosa were amplified by polymerase chain reaction (PCR) and reverse transcription PCR, using synthetic oligonucleotide primers to cagA genes to compare the prevalence of cagA genes in 35 patients with non-ulcer gastritis and 99 patients with gastric or duodenal ulcer disease (53 and 46, respectively). Two different primer sets for the cagA gene were used. The first primer set amplified a 298-bp region (nucleotides 1751-2048), and the second set amplified a 349-bp region (nucleotides 1228-1249). RESULTS: The expected 298 and 349-bp PCR amplicons were identified as follows: 1) 32 (91.4%) and 30 (85.7%) of 35 non-ulcer gastritis patients; 2) 5 1 (96.2%) and 50 (94.3%) of 53 benign gastric ulcer patients; and 3) 46 (100.0%) and 40 (87.0%) of 46 duodenal ulcer patients, respectively. CONCLUSION: These results strongly suggest that the cagA gene will not prove to be a useful marker to distinguish disease-specific H. pylori strains in the development of peptic ulcer diseases in Korean patients.

Antigens, Bacterial↗
PubMed1998

DIVCLUS: an automatic method in the GEANFAMMER package that finds homologous domains in single- and multi-domain proteins.

MOTIVATION: Large-scale determination of relationships between the proteins produced by genome sequences is now common. All protein sequences are matched and those that have high match scores are clustered into families. In cases where the proteins are built of several domains or duplication modules, this can lead to misleading results. Consider the very simple example of three proteins: 1, formed by duplication modules A and B; 2, formed by duplication modules B' and C; and 3, formed by duplication modules C' and D. Duplication modules B and B' are homologous, as are C and C'. Matching the sequences of 1, 2 and 3 followed by simple single-linkage clustering would put all three in the same family, even though proteins 1 and 3 are not related. This is because the different parts of 2 match 1 and 3. This paper describes a procedure, DIVCLUS, that divides such complex clusters of partially related sequences into simple clusters that contain only related duplication modules. In the example just given, it would produce two groups of sequences: the first with domains B of sequence 1 and B of sequence 2, and the second with domain C of sequence 2 and C of sequence 3. DIVCLUS is part of a package called GEANFAMMER, for GEnome ANalysis and protein FAMily MakER. The package automates the detection of families of duplication modules from a protein sequence database. RESULTS: DIVCLUS has been applied to the division of single-linkage clusters generated from the protein sequences of six completely sequenced bacterial genomes. Out of 12 013 genes in these six genomes, 4563 single- and multi-domain sequences formed 1071 complex clusters. Application of the DIVCLUS program resolved these clusters into 2113 clusters corresponding to single duplication modules. AVAILABILITY: The perl5 program and its documentation are available at the following address: http://www.mrc-lmb.cam.ac.uk/genomes/ and by anonymous ftp at ftp.mrc-lmb.cam.ac.uk in the directory /pub/genomes/Software/. CONTACT: sat@mrc-lmb.cam.ac.uk; jong@mrc-lmb. cam.ac.uk

Algorithms↗
PubMed1998

Perceptions of the collective other.

It is contended that perceptions of groups are affected by particular variables that do not apply to individuals (e.g., intragroup similarity and proximity). Importantly, the perception of outgroup threat has incomplete analogs at the individual level. Results from 3 studies support predictable distinctions between representations of individuals and of groups. Study I showed that priming of the word they produces more extreme negative judgments of the protagonist(s) in a story about 4 individuals acting jointly than in the same story with a single person acting alone. The opposite result holds for priming with the word he. Study 2, with Korean participants, demonstrates that actions by individuals or groups elicit differing preferences for redress. Individual responses (e.g., getting mad) to an individual racial insult (e.g., a snub by a waitress) are preferred to collective responses (e.g., circulating a petition), whereas the reverse preferences hold for a group insult (e.g., taunts from a gang of White youths). In Study 3, cues to the sensitivity of a group are introduced. This concept, introduced by Donald Campbell (1958), distinguishes different degrees of "groupness." Visual depictions of collections of unfamiliar humanoid creatures (greebles) were used to convey that they were either similar or dissimilar and either proximate or scattered. Results confirm the expectation that similarity and proximity-two entitive conditions-elicit more negative judgments of the group. Attention to other cues for entitivity may enrich social psychological views of stereotyping and prejudice by focusing on perceptions of groups as coordinated actors with the potential to bring about negative consequences. Such experiments point to the need for greater research focus on the vastly understudied but fundamental problem of the social cognition of group behavior.

Journal Article↗
PubMed1998

Transcription of the rat p53 gene is mediated by factor binding to two recognition motifs of NF1-like protein.

In this study we analyzed the ratp53 promoter by electrophoretic mobility shift assay (EMSA) and DNase I footprinting analysis. As a result we identified two protein binding elements (element 1: -296 to -312, element 2: -195 to -219) with sequence homology to each other. The two identified elements bind to the same kind of protein. To identify the protein binding to these elements, competition assays were carried out with double stranded oligonucleotides containing NF1, YY1, and CRE consensus motifs. Only the NF1 consensus motif competed with element 1 and 2. Element 2 is conserved between the rat, human, and mouse p53 promoters, and has an NF1 consensus motif. However, the sequences of element 1 are comparatively variable between the species. Only the element 1 region of the rat p53 promoter has partial homology to the NF1 consensus motif. This suggests that the element 1 is specific for the rat p53 gene. The molecular mass of the binding protein, determined by Southwestern blotting analysis, was 40 kDa, which is different from that of NF1. In EMSA with an anti-NF1 antibody, DNA-protein complexes were neither supershifted nor decreased. The 40 kDa protein was also detected in rat spleen and lung, but not in kidney. The binding protein was purified by sequence-specific DNA affinity chromatography and it was confirmed that the purified protein binds to the two regions. It was also proved that the identified two elements are required for basal level transcription of the rat p53 gene by in vitro transcription assay.

Animals↗
PubMed1998

The history of occupational health service in Korea.

The following study was conducted to closely examine the evolution and formation of the occupational health service system in Korea during different historical periods. Korea's industrial structure has changed rapidly in the last 30 years from 1960's to 1990's, moving from a primary industry to a secondary or tertiary focused structure. Industrial accidents and occupational diseases are related closely to industrialization. Also, the new occupational health service system of each historical period has its political background. Until the mid 1980's, Korea's Occupational Health Service System was more a by-product of contemporary political, social, and economical situations rather than an effort to aggressively solve domestic industrial safety and health problems presented by laborers on the basis of academic development of industrial medicine. Therefore, the methods were to bestow a favor or one-sided. However, as Korea achieved democracy toward the end of the 1980's, it can be seen that industrial safety administration leaned toward actively dealing with the social demands of the working class.

Accidents, Occupational↗
PubMed1998

In vitro inhibition of biophysical surface properties and change in ultrastructures of exogenous pulmonary surfactant by albumin or fibrinogen.

In order to observe the effects of serum albumin and fibrinogen on biophysical surface properties and the morphology of pulmonary surfactant in vitro, we measured the surface adsorption rate, dynamic minimum and maximum surface tension (min-, max-ST) by Pulsating Bubble Surfactometer, and demonstrated ultrastructures on a series of mixtures with varying concentrations of albumin or fibrinogen and Surfactant-TA. The albumin and fibrinogen significantly inhibited the adsorption rate and ST-lowering properties of surfactant through increasing STs of adsorption rate, min-ST, and max-ST. The characteristic morphology of the Surfactant-TA changed from lamellar rod-like structure with open ends into spherical structures with loss of their open ends by mixing with albumin or fibrinogen. These inhibitory effects of albumin and fibrinogen on surface properties of surfactant were dependent upon the increasing concentration of albumin or fibrinogen. We concluded that albumin and fibrinogen significantly altered surfactant function and its ultrastructural morphology in vitro. These findings support the concept that albumin and fibrinogen-induced surfactant dysfunction may play an important role in the pathophysiology of adult respiratory distress syndrome, and this adverse effect of albumin and fibrinogen on surfactant might be overcome by administration of large doses of exogenous surfactant.

Adsorption↗
PubMed1998

YUA001, a novel aldose reductase inhibitor isolated from alkalophilic Corynebacterium sp. YUA25. I. Taxonomy, fermentation, isolation and characterization.

YUA001 is a novel aldose reductase inhibitor produced from alkalophilic Corynebacterium sp. YUA25 isolated from soil. YUA001 was purified from the supernatant of culture broth by successive silica gel column chromatography, Sephadex LH20-100 gel column chromatography, and HPLC. From instrumental analysis, molecular formula of YUA001 is C13H19NO2 and its molecular weight is 221. It exhibits potent aldose reductase inhibition activity and has no antimicrobial activity against some gram-positive or gram-negative bacteria, fungi and yeast.

Aldehyde Reductase↗
PubMed1998

The investigation of stress in resource-dependent communities: the effect of rapid socioeconomic changes on mental health service use.

Drawing on census data and psychiatric hospital records, this paper examines the impact of rapid socioeconomic change on the mental health of residents in Northwestern Ontario resource-dependent communities. This research investigates whether residents in economically growing and declining communities experience more mental distress and use more psychiatric services than people in stable communities. Findings show socio-demographic change is associated with significant differences in psychiatric hospital utilization between different types of communities, with bust communities illustrating the highest rates (5.5/1,000). Furthermore, acute stress symptoms are reported much more frequently in bust and boom communities than in stable communities. Results of multiple regression analysis indicate that decreasing household income level also contributes to increasing rates of mental health service utilization.

Adult↗
PubMed1998

Complete left ventricular wall motion estimation from cascaded MRI-SPAMM data.

We present a new paradigm which incorporates multiple sets of tagged MRI data (MRI-SPAMM) acquired in a cascaded fashion in order to estimate the full 3-D motion of the left ventricle (LV) during its entire cardiac cycle. Our technique is based on the extension of the volumetric physics-based deformable models, whose parameters are functions, which can capture the local shape variation of an object with a small number of intuitive parameters. By integrating a cascaded sequence of SPAMM data sets into our modeling technique, we have extended the capability of MRI-SPAMM and have provided an accurate representation of the LV motion from end-diastole to end-diastole to better understand cardiac mechanics.

Algorithms↗