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Biomedical subjects

S Hong

Publications and source records attributed to S Hong.

At least 55 records · Page 3Linked to original sources
PubMed2001

Cultural value similarities and differences among Asian American ethnic groups.

Using data on 570 Chinese, Filipino, Korean, and Japanese American college students from 3 previous studies (1 published [B. S. K. Kim, D. R. Atkinson, & P. H. Yang, 1999] and 2 unpublished [B. S. K. Kim, 1999; E. C. Wong, B. S. K. Kim, N. W. S. Zane, I. J. Kim, & J. S. Huang, 1999]), the authors subjected 22 items constituting 6 value dimensions of the Asian Values Scale (AVS; B. S. K. Kim et al., 1999) to the following structural equation modeling procedures: confirmatory factor analysis, factorial invariance analysis, and structured means analysis. The results of confirmatory factor analysis provided support for a hierarchical factor model when this model was compared with 2 competing models. The results of factorial invariance analysis indicated that the meanings of the factors within the hierarchical model were conceived similarly among the 4 Asian American ethnic groups. On the basis of these results, a structured means analysis was conducted, revealing similarities and differences between the ethnic groups' adherence to 6 cultural value dimensions. Implications regarding psychological services for these Asian Americans are discussed, and suggestions for future research are offered.

Adolescent↗
PubMed2001

Antigen-induced translocation of PKC-theta to membrane rafts is required for T cell activation.

Protein kinase C-theta (PKC-theta) is essential for mature T cell activation; however, the mechanism by which it is recruited to the TCR signaling machinery is unknown. Here we show that T cell stimulation by antibodies or peptide-major histocompatibility complex (MHC) induces translocation of PKC-theta to membrane lipid rafts, which localize to the immunological synapse. Raft translocation was mediated by the PKC-theta regulatory domain and required Lck but not ZAP-70. In addition, PKC-theta was associated with Lck in the rafts. An isolated PKC-straight theta catalytic fragment did not partition into rafts or activate the transcription factor NF-kappa B, although addition of a Lck-derived raft-localization sequence restored these functions. Thus, physiological T cell activation translocates PKC-theta to rafts, which localize to the T cell synapse; this PKC-theta translocation is important for its function.

Antigen-Presenting Cells↗
PubMed2001

The natural killer T-cell ligand alpha-galactosylceramide prevents autoimmune diabetes in non-obese diabetic mice.

Diabetes in non-obese diabetic (NOD) mice is mediated by pathogenic T-helper type 1 (Th1) cells that arise because of a deficiency in regulatory or suppressor T cells. V alpha 14-J alpha 15 natural killer T (NKT) cells recognize lipid antigens presented by the major histocompatibility complex class I-like protein CD1d (refs. 3,4). We have previously shown that in vivo activation of V alpha 14 NKT cells by alpha-galactosylceramide (alpha-GalCer) and CD1d potentiates Th2-mediated adaptive immune responses. Here we show that alpha-GalCer prevents development of diabetes in wild-type but not CD1d-deficient NOD mice. Disease prevention correlated with the ability of alpha-GalCer to suppress interferon-gamma but not interleukin-4 production by NKT cells, to increase serum immunoglobulin E levels, and to promote the generation of islet autoantigen-specific Th2 cells. Because alpha-GalCer recognition by NKT cells is conserved among mice and humans, these findings indicate that alpha-GalCer might be useful for therapeutic intervention in human diseases characterized by Th1-mediated pathology such as Type 1 diabetes.

Animals↗
PubMed2001

Ergolide, sesquiterpene lactone from Inula britannica, inhibits inducible nitric oxide synthase and cyclo-oxygenase-2 expression in RAW 264.7 macrophages through the inactivation of NF-kappaB.

We investigated the mechanism of suppression of inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) by ergolide, sesquiterpene lactone from Inula britannica. iNOS activity in cell-free extract of LPS/IFN-gamma-stimulated RAW 264.7 macrophages was markedly attenuated by the treatment with ergolide. Its inhibitory effect on iNOS was paralleled by decrease in nitrite accumulation in culture medium of LPS/IFN-gamma-stimulated RAW 264.7 macrophages in a concentration-dependent manner. However, its inhibitory effect does not result from direct inhibition of the catalytic activity of NOS. Ergolide markedly decreased the production of prostaglandin E(2) (PGE(2)) in cell-free extract of LPS/IFN-gamma-stimulated RAW 264.7 macrophages in a concentration-dependent manner, without alteration of the catalytic activity of COX-2 itself. Ergolide decreased the level of iNOS and COX-2 protein, and iNOS mRNA caused by stimulation of LPS/IFN-gamma in a concentration-dependent manner, as measured by Western blot and Northern blot analysis, respectively. Ergolide inhibited nuclear factor-kappaB (NF-kappaB) activation, a transcription factor necessary for iNOS and COX-2 expression in response to LPS/IFN-gamma. This effect was accompanied by the parallel reduction of nuclear translocation of subunit p65 of NF-kappaB as well as IkappaB-alpha degradation. In addition, these effects were completely blocked by treatment of cysteine, indicating that this inhibitory effect of ergolide could be mediated by alkylation of NF-kappaB itself or an upstream molecule of NF-kappaB. Ergolide also directly inhibited the DNA-binding activity of active NF-kappaB in LPS/IFN-gamma-pretreated RAW 264.7 macrophages. These results demonstrate that the suppression of NF-kappaB activation by ergolide might be attributed to the inhibition of nuclear translocation of NF-kappaB resulted from blockade of the degradation of IkappaB and the direct modification of active NF-kappaB, leading to the suppression of the expression of iNOS and COX-2, which play important roles in inflammatory signalling pathway.

Active Transport, Cell Nucleus↗
PubMed2001

Pattern analysis of sleep-deprived human EEG.

Progress during the past decade in non-linear dynamics and instability theory has provided useful tools for understanding spatio-temporal pattern formation. Procedures which apply principle component analysis (using the Karhunen-Loeve decomposition technique) to the multichannel electroencephalograph (EEG) time series have been developed. This technique shows localized changes of cortical functioning; it identifies increases and decreases of the activity of localized cortical regions over time while the subject performs a simple task or test. It can be used to demonstrate the change in cortical dynamics in response to a continuous challenge. Using 16 EEG electrodes, the technique provides spatio-temporal information not obtained with power spectrum analysis, and includes the weighted information given with omega complexity. As an application, we performed a pattern analysis of sleep-deprived human EEG data in 20 healthy young men. Electroencephalograph recordings were performed on subjects for <2 min, with eyes closed after normal sleep and after 24 h of experimentally-induced sleep deprivation. The significant changes in the eigenvector components indicated the relative changes of local activity in the brain with progressive sleep deprivation. A sleep deprivation effect was observed, which was hemispherically correlated but with opposite directional dynamics. These changes were seen in the temporo-parietal regions bilaterally. The application of the technique showed that the simple test task was performed with a limited unilateral hemispheric involvement at baseline, but needed a much larger cortical participation with decreased frontal activity and increased coherence and bilateral hemispheric involvement. The calculations performed demonstrated that the same weighted changes as those obtained with omega complexity were shown, but the technique had the added advantage of showing the localized directional changes of the principle eigenvector at each studied electrode, pointing out the cortical localized region affected by the sleep deprivation and toward which direction the environmental challenge induced the spatial change. This methodology may allow the evaluation of changes in local dynamics in brain activity in normal and pathological conditions.

Adult↗
PubMed2001

Cloning and expression analysis of rainbow trout Oncorhynchus mykiss tumour necrosis factor-alpha.

A rainbow trout (Oncorhynchus mykiss) gene for tumor necrosis factor (TNF) has been cloned and sequenced. The cDNA contains an open reading frame of 738 nucleotides that translate into a 246 amino-acid putative peptide, with a 5' untranslated region (UTR) of 140 bp and a 3' UTR of 506 bp. Two potential N-linked glycosylation sites exist in the translation. The genomic sequence measures 2007 bp and contains three introns that intercept four coding exons. Expression studies using RT-PCR have shown that the trout TNF gene is constitutively expressed in the gill and kidney of unstimulated fish. Trout TNF expression could be up-regulated by stimulation of isolated head kidney leucocytes with lipopolysaccharide (LPS). Similarly, stimulation of a trout macrophage cell line (RTS11) with LPS resulted in an increased transcript level, as did incubation with recombinant trout interleukin (IL)-1 beta. The optimal timing for induction of TNF expression in trout macrophages was determined using recombinant trout IL-1 beta, where a clear induction was apparent by 2 h and peaked at 4 h. Evidence that this TNF gene is equivalent to mammalian TNF-alpha is discussed.

Amino Acid Sequence↗
PubMed2001

Synergistic antidiabetic activities of zinc, cyclo (his-pro), and arachidonic acid.

Previous studies have already shown that prostate extract (PE) has antidiabetic activity when given to animals and humans. In this study, we explore whether this antidiabetic activity is related to the high concentrations of zinc, cyclo (his-pro) (CHP), and the prostaglandin precursor, arachidonic acid (AA), in prostate tissue. When streptozotocin-induced diabetic rats were given drinking water containing 10 mg/L zinc and 100 mg/L PE for 3 weeks, fasting blood glucose levels and glucose clearance rates, but not plasma insulin levels, were significantly lower than at pretreatment. In subsequent experiments, blood glucose levels in rats given PE for 3 weeks were significantly lower than in rats given distilled water or 10 mg/L zinc alone. However, in rats given 100 mg/L CHP with zinc, blood glucose levels were also lower than in rats given PE alone. Time-course studies in diabetic rats given drinking water containing 20 mg/L Zn, 20 mg/L L-histidine, and 10 mg/L CHP showed that blood glucose levels dropped 209 +/- 53 mg/dL in 1 day and stayed low for 2 weeks. When CHP was replaced with 100 mg AA/L, blood glucose levels dropped 230 +/- 64 mg/dL in 5 days, but returned to the original values 11 days later. Growth rate improved and water consumption decreased significantly in CHP- and AA-treated diabetic rats. High intake of L-histidine and testosterone increased blood glucose concentrations in diabetic rats. To determine optimal dosages of CHP and AA, we gave rats drinking water containing 10 mg/L Zn and 0.5 mg/L L-histidine with various concentrations of CHP or AA. The most effective doses for reducing blood glucose levels were 0.32 mg CHP/kg/day and 11 mg AA/kg/day. These data suggest that the active antidiabetic ingredients in the PE are CHP, zinc, and AA or its precursors.

Animals↗
PubMed2001

Adsorption of ferrous iron on the lepidocrocite surface.

This study explored the ferrous iron adsorption capacity of three synthesized lepidocrocites as well as their morphology and surface area. Their morphologies were observed using scanning electron microscopy (SEM) and their surface areas were measured by BET isotherm techniques using nitrogen gas at the liquid nitrogen temperature. The adsorption capacities of the three distinctive lepidocrocites were measured and the data were processed by multiple regression technique to obtain the adsorption constants in the proposed model. The microphotographs of the lepidocrocites revealed that lepidocrocites could have an acicular shape as well as the shape of agglomerated flocs. The surface areas of the synthesized lepidocrocites in this study varied widely from 48.98 m2 g(-1) to 150.28 m2 g(-1). Adsorption capacities of three distinctive lepidocrocites for ferrous iron were investigated at four different pH levels. It was observed that there was no correlation between the BET surface area and adsorption capacity. The sites accessible to nitrogen gas might not be available to ferrous iron in water. An adsorption model based on the Freundlich equation was built to predict the effect of pH and the equilibrium concentration of ferrous iron in water. Multiple regression of data revealed that the amount of ferrous iron adsorbed on the unit weight of lepidocrocite was proportional to the 0.57 power of the ferrous iron concentration and inversely proportional to the 0.66 power of the hydrogen ion concentration.

Adsorption↗
PubMed2001

Sorption and mobility of dithiopyr in golf course greens rooting medium.

Sorption and mobility of dithiopyr in golf course greens rooting medium (RM) were studied. The sorption increased from 20 to 27 degrees C at 24 h after treatment (HAT) and reached equilibrium in 48 HAT at 20 degrees C. The sorption isotherms had Freundlich values (KF) of 1122, 27.44 to 35.16, and 0.053 to 0.168 for peat moss, the RM, and quartz sand, respectively, and solid to aqueous phase partition coefficients (Kd) of 470 to 1706 L/kg, 14.61 to 84.4 L/kg, and 0.07 to 0.29 L/kg for peat moss, RM, and quartz sand, respectively. Generally, higher dithiopyr concentration in the aqueous solution and the reduced pH of the solution corresponded to the higher Kd values. The average values for dispersion (D, cm2/min), retardation coefficient (R), beta, and omega parameters for solute transport in the RM lysimeter; obtained from CXTFIT curve fitting of Br- breakthrough curves; were 0.95, 1.01, 1, and 93.89, respectively. After elutriation by 18 L of aqueous KNO3 (10 mM), greater than 90% of the added dithiopyr remained in the top 10 cm of the RM lysimeter and no detectable dithiopyr was present at depths beyond 35 cm. The lysimeter effluent contained dithiopyr at concentrations less than 3.5 microg/L. The R value obtained from CXFIT curve fitting is 38.5. Results from both sorption and mobility experiments indicated that dithiopyr is quite immobile in golf course greens RM and has minimal potential for movement into surface water drainage or ground water.

Adsorption↗
PubMed2001

Analytical method development for 18 pesticides in house dust and settled residues using SEC, SPE, TMS methylation, and GC-MS.

An analytical method is developed to analyze eighteen pesticides in carpet dust and also dust that has settled on surfaces in order to determine the potential exposure of children to pesticide residues. For nonacid pesticides, the extract after centrifugation and filtration is cleaned up using size-exclusion chromatography (SEC) and then analyzed by gas chromatography (GC) coupled with a mass spectrometer (MS). The best solvent for extraction is ethyl acetate-cyclohexane (3:1). The recoveries of spiked nonacid pesticides from 2 g of dust are between 72% and 110% with a variation between 4.2% and 25.6%, and the detection limit is 10 to 50 ng/g dust, depending on the pesticide. For acid pesticides, the dust is extracted with a saturated Ca(OH)2 solution, centrifuged, cleaned up by polyvinylbenzene/polystyrene-type solid-phase extraction cartridges, and methylated with trimethylsilyldiazomethane (TMS). Acid pesticides on filter paper samples are extracted with acidified acetone (3 mM H3PO4) and methylated with TMS. Methylation with TMS is fast and easy to perform. Methyl esters of the pesticides are completely separated and detected at low levels by GC-MS in the selective ion monitoring mode. The average recoveries of pesticides from 2 g of dust are between 81% and 104%. The average recoveries of pesticides spiked on filter paper are between 88% and 113%. A capillary column with a stationary phase of trifluoropropylmethyl polysiloxane gives the best separation and sensitivity for most pesticides on the GC-MS.

Carboxylic Acids↗
PubMed2001

An evaluation of the changes in malocclusion index scores over a 25-year period.

BACKGROUND: The measured values of specific traits of occlusion may be subject to significant change due to growth and maturation of the dentofacial structures. Some traits may show improvement while others may show deterioration. Rarely is there an opportunity to examine a sample of occlusions 25 years after the acquisition of the original set of records. This study examines the changes in traits of occlusion in a sample of 46 subjects who were originally examined between 1971-1973 and for whom records were again obtained in 1998. METHODS: The 46 patients were a sub-group of a previously selected randomised school-based sample and study models obtained in 1971-1973 were still available. New models for each patient were obtained in 1998. Of the 46 subjects, only eight had received orthodontic treatment. RESULTS: Assessments of the changes in specific traits were made using the methods proposed in the Harry L Draker, California Modification (HLD Cal Mod) index. This simple index was chosen because the main component traits were well defined and, when analysed separately, reflected changes with time. The total index score gave a broad indication of the global changes in the individual's occlusion. The five basic traits of the HLD index include overjet, overbite, openbite, mandibular protrusion and labio-lingual spread. Three additional traits (ectopic eruption, anterior crowding and posterior crossbite) are used in the HLD Cal Mod index. These traits provided a useful reflection of occlusal changes with time. Measurements were made with reference to specifications and the details outlined in the HLD Cal Mod protocol. The results revealed an increase in total index scores over time with a significant increase in lower labio-lingual spread associated with an increased score in anterior crowding. Overjet and overbite, however, displayed a significant decrease with time. CONCLUSIONS: These findings are in keeping with previous studies and highlight the importance of time as a significant issue in the assessment of occlusion.

Adult↗
PubMed2001

Type D retrovirus Gag polyprotein interacts with the cytosolic chaperonin TRiC.

The carboxy terminus-encoding portion of the gag gene of Mason-Pfizer monkey virus (M-PMV), the prototype immunosuppressive primate type D retrovirus, encodes a 36-amino-acid, proline-rich protein domain that, in the mature virion, becomes the p4 capsid protein. The p4 domain has no known role in M-PMV replication. We found that two mutants with premature termination codons that remove half or all of the p4 domain produced lower levels of stable Gag protein and of self-assembled capsids. Interestingly, yeast two-hybrid screening revealed that p4 specifically interacted with TCP-1gamma, a subunit of the chaperonin TRiC (TCP-1 ring complex). TRiC is a cytosolic chaperonin that is known to be involved in both folding and subunit assembly of a variety of cellular proteins. TCP-1gamma also associated with high specificity with the M-PMV pp24/16-p12 domain and human immunodeficiency virus p6. Moreover, in cells, Gag polyprotein associated with the TRiC chaperonin complex and this association depended on ATP hydrolysis. In the p4 truncation mutants, the Gag-TRiC association was significantly reduced. These results strongly suggest that cytosolic chaperonin TRiC is involved in Gag folding and/or capsid assembly. We propose that TRiC associates transiently with nascent M-PMV Gag molecules to assist in their folding. Consequently, properly folded Gag molecules carry out the intermolecular interactions involved in self-assembly of the immature capsid.

Capsid↗
PubMed2001

Comparison of pupil perimetry and visual perimetry in normal eyes: decibel sensitivity and variability.

PURPOSE: To compare the sensitivity and variability of pupil perimetry with visual perimetry at the same retinal locations in normal subjects. METHODS: Pupil perimetry was performed on the right and left eyes of 10 normal subjects using a computerized infrared pupillometer equipped to present perimetric light stimuli and record pupil light reflexes. Eleven locations were tested at different intensities along the horizontal meridian of each eye, and the decibel sensitivity of the pupil light reflex was compared with the visual threshold at the same location. RESULTS: The shape and height of the hill of vision (retinal sensitivity) was very similar between the right and left eyes of each individual using either pupil perimetry (R2 = 0.69) or standard threshold perimetry (R2 = 0.62) but was less similar between subjects. Comparisons between pupil and visual sensitivity revealed a lack of correlation at the same retinal location in normal eyes (R2 = 0.19). CONCLUSIONS: The high intereye correlation for either pupil or visual sensitivity may provide an important tool for detecting focal or asymmetric visual field damage. Although the basic shape of the sensitivity profile of pupil and visual responses was similar under the conditions of testing, the two did not correlate well within each eye among the normal subjects. This highlights that similarities do exist in the sensitivity profile of the two pathways, but they do not seem to vary in the same proportion between normal individuals.

Adult↗
PubMed2001

Primary effusion lymphoma with herpesvirus 8 DNA in patients coinfected with HIV and hepatitis C virus: a report of 2 cases.

The primary effusion lymphoma (PEL), commonly described in patients with AIDS, is a unique subset of diffuse large cell lymphoma in which the malignant lymphocytes proliferate exclusively in serous cavities. The cytologic, immunophenotypic, and molecular features of PEL are presented from findings of 2 patients coinfected with HIV and hepatitis C virus who presented with abdominal pain. Abdominal radiography in both patients displayed marked peritoneal effusions. Cytomorphologic examination of peritoneal fluid revealed a malignant lymphoma in both. Their immunophenotypic expression was CD30 (Ki-1) and epithelial membrane antigen. Molecular analysis demonstrated human herpesvirus 8 DNA in both patients and bcl-2 oncogene rearrangement within the major breakpoint region of t(14;18) chromosome translocation in Case B only. Clinical correlation supports the current concept that PEL represents a primary HIV/AIDS-related lymphoma in effusion. Cytomorphologic examination of body cavity fluid serves as a tool for the initial diagnosis of PEL.

Adult↗
PubMed2001

[An new filling material of hair for the application of plastic surgery].

OBJECTIVE: To investigate the possibility of hair as a filling material for reconstructive or cosmetic surgery. METHODS: Sterilized pellets of hairs and silicone were selected and implanted subcutaneously in white rabbits. The clinical trial was carried out in 3 cases. RESULTS: A thin fibrous capsule, with much few inflammatory cells, was formed around the implanted hair pellets in 3-4 months. The inflammatory cells disappeared in the 9th month. No implant rejection, granulomatous formation or hair degradation was showed. CONCLUSION: Hair may be a valuable filling material for augmentation of the soft tissue.

Adult↗
PubMed2001

[A population-based surveillance system on birth defects and its application].

OBJECTIVE: To describe a unique surveillance system on birth defects in the People's Republic of China. METHODS: The system was instituted in 1992 as a component for the evaluation on the effectiveness of a community intervention program using periconceptional folic acid supplementation to prevent neural tube defects and currently carries out surveys on a birth cohort of approximately 150 000 infants per year. Information was collected in the form of detailed written descriptions by local health care providers and photographs of affected infants. The system allowed for detection of birth defects at the local level with later definitive classification and coding; however, information was limited to those structural anomalies which were visible on physical examination. RESULTS: This surveillance system on birth defects provides an extensive database of infants with major and minor external structural anomalies. From 1993 to 1996, more than one million births were monitored, with more than 10 000 birth defects and 30 000 photos submitted. Among them 5 000 were identified with major birth defects. Neural tube defects, oral clefts and extremity abnormalities were the first few defects with most cases. Data were used in birth defect surveillance reports and scientific papers. CONCLUSIONS: This system can be utilized for studies on etiology, descriptive epidemiology, and identification of unusual trends which is unique with multiple advantages in the People's Republic of China.

Congenital Abnormalities↗
PubMed2001

[The changes of serum levels of interleukin-6 and interleukin-8 in pregnant women with systemic lupus erythematosus].

OBJECTIVE: To assess the changes of serum levels of interleukin-6(IL-6) and interleukin-8 (IL-8) in pregnant women with stationary phase systemic lupus erythematosus (SLE). METHODS: Enzyme-linked immunosorbent assay (ELISA) was used to measure serum IL-6 and IL-8 from 14 pregnant women with stationary phase SLE (SLE group), 12 normal pregnant women (normal pregnant group) and 12 normal non-pregnant women (group normal non-pregnant). The later two groups are set as controls. RESULTS: The IL-6, IL-8 levels in group SLE patients are (20.31 +/- 5.70) ng/L and (48.80 +/- 9.17) ng/L, significantly higher than those in normal pregnant group [IL-6, IL-8 levels are (8.40 +/- 2.49) ng/L and (21.15 +/- 5.21) ng/L, respectively, P < 0.01)] and normal non-pregnant group [IL-6, IL-8 levels are (6.14 +/- 0.86) ng/L and (17.71 +/- 4.43) ng/L, respectively, P < 0.01]. However, there's no significant difference between the normal pregnant group and normal non-pregnant group (P > 0.05). CONCLUSION: Serum levels of IL-6, IL-8 may be helpful to monitor the progress of SLE during pregnancy.

Adult↗