Characteristics and clinical implications of premature summation of early and late diastolic filling in patients without tachycardia

Backgrounds

The summation of early (E) and late diastolic filling (A) on mitral inflow Doppler even in the absence of tachycardia is often found during assessments of left ventricular (LV) diastolic function. We evaluated the echocardiographic characteristics and clinical implications of premature E-A summation.

Methods

We identified 1,014 subjects who showed E-A summation and normal LV ejection fraction between January 2019 and June 2021 in two tertiary hospitals. Among these, 105 (10.4%) subjects showed premature E-A summation at heart rates less than 100 beats per minute (bpm). The conventional echocardiographic parameters and LV global longitudinal strain (GLS) were compared with 1:1 age, sex, and heart rate matched controls without E-A summation.

Results

The premature E-A summation group had a heart rate of 96.4±3.7 bpm. Only 4 (3.8%) subjects were classified as having LV diastolic dysfunction according to the current guidelines. That group showed prolonged isovolumic relaxation time (107.2±25.3 vs. 61.6±15.6 msec, p<0.001), increased Tei index (0.76±0.19 vs. 0.48±0.10, p<0.001), lower LVEF (63.8±7.0 vs. 67.3±5.6%, p<0.001) and lower absolute LV GLS (|LV GLS|) (17.0±4.2 vs. 19.7±3.3%, p<0.001) than controls. As the E-A summation occurred at lower heart rate, the |LV GLS| was also lower (p for trend=0.002).

Conclusions

The premature E-A summation at heart rates less than 100 bpm is associated with subclinical LV dysfunction. Time-based indices and LV GLS are helpful for evaluating this easily overlooked population.

Funding Acknowledgement

Type of funding sources: None.

Racial and ethnic differences in cognitive health appraisals: a comparison of non-Hispanic White, non-Hispanic Black, and Hispanic older adults

OBJECTIVES

To investigate the relationship between cognitive performance and cognitive health appraisals across non-Hispanic White, non-Hispanic Black, and Hispanic older adults in the United States and to explore within-group variations by examining interactions between cognitive performance and background and health variables.

METHOD

The sample (N = 3,099) included 2,260 non-Hispanic White, 498 non-Hispanic Black, and 341 Hispanic adults aged 65 or older, from the 2016-2017 Harmonized Cognitive Assessment Protocol. Regression models of cognitive health appraisals, indicated by self-rated cognitive health, were examined in the entire sample and in racial and ethnic subgroups to test direct and interactive effects of cognitive performance, indicated by the Mini-Mental State Examination (MMSE).

RESULTS

The regression model for the entire sample showed direct effects of cognitive performance and race/ethnicity on cognitive health appraisals, as well as a significant interaction between cognitive performance and being non-Hispanic Black. Cognitive performance and cognitive health appraisals were positively associated in non-Hispanic Whites but not significantly associated in non-Hispanic Blacks. Our subsequent analysis within each racial/ethnic group showed that the effect of cognitive performance in non-Hispanic Blacks and Hispanics became either reversed or nonsignificant when background and health variables were considered. Modification by age or chronic medical conditions in each racial and ethnic group was also observed.

CONCLUSION

Overall, these findings suggest that perceptions and appraisals of cognitive health vary by race and ethnicity and hold implications for how these differences should be considered in research and practice with diverse groups of older adults.

Myocardial extracellular space expansion is related to burden of premature ventricular contractions in patients with hypertrophic cardiomyopathy without non-sustained ventricular tachycardia

Funding Acknowledgements

Type of funding sources: None.

Background

Current guidelines suggest the presence of non-sustained ventricular tachycardia (NSVT) as a risk factor of sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). However, high burden of premature ventricular contraction (PVC) may reflect myocardial fibrosis although the absence of NSVT.

Purpose

We investigated the association between PVC burden and myocardial extracellular space expansion in HCM patients without NSVT.

Methods

Of the 212 patients prospectively enrolled to the HCM registry of genetics, 84 patients were evaluated with both cardiac magnetic resonance and 24hr holter. Among them, 71 patients (58 males, mean age: 71 ± 13 years) have not been diagnosed with NSVT.

Results

Patients with NSVT (n = 13) showed more impaired LA functional indices and higher myocardial fibrosis burden compared with patients without NSVT (n = 71). Among patients who have not been diagnosed with NSVT, patients with late gadolinium enhancement (LGE, n = 46) had a higher total beats (109 ± 332 vs. 7 ± 13 beats per a day, p = 0.003) and burden (0.114 ± 0.225 vs. 0.008 ± 0.014 %, p = 0.003) of PVC during 24-hour compared with patients without LGE (n = 25). %LGE was correlated with total beats of PVC (r = 0.358, p = 0.002) and PVC burden (r = 0.377, p = 0.001). ECV also correlated with total beats of PVC (r = 0.387, p = 0.001) and PVC burden (r = 0.401, p = 0.001). The optimal cutoff value for PVC number was 45 (37.0% of sensitivity and 100% of specificity) with 0.733 of the area under the ROC curve (p < 0.001). Pathogenic or likely pathogenic sarcomere mutation was higher in NSVT group than no NSVT group (p < 0.05), and had a higher tendency in higher PVC burden group (0.05 < p < 0.1) than lower PVC burden group.

Conclusions

Total beats and burden of PVC are significantly related to increase in myocardial fibrosis in HCM patients without NSVT.

Abstract Figure. Mechanism of ventricular arrhythmia

Quantitative T1 Mapping for Detecting Microvascular Obstruction in Reperfused Acute Myocardial Infarction: Comparison with Late Gadolinium Enhancement Imaging

Objective

To compare native and post-contrast T1 mapping with late gadolinium enhancement (LGE) imaging for detecting and measuring the microvascular obstruction (MVO) area in reperfused acute myocardial infarction (MI).

Materials and Methods

This study included 20 patients with acute MI who had undergone 1.5T cardiovascular magnetic resonance imaging (CMR) after reperfusion therapy. CMR included cine imaging, LGE, and T1 mapping (modified look-locker inversion recovery). MI size was calculated from LGE by full-width at half-maximum technique. MVO was defined as an area with low signal intensity (LGE) or as a region of visually distinguishable T1 values (T1 maps) within infarcted myocardium. Regional T1 values were measured in MVO, infarcted, and remote myocardium on T1 maps. MVO area was measured on and compared among LGE, native, and post-contrast T1 maps.

Results

The mean MI size was 27.1 ± 9.7% of the left ventricular mass. Of the 20 identified MVOs, 18 (90%) were detected on native T1 maps, while 10 (50%) were recognized on post-contrast T1 maps. The mean native T1 values of MVO, infarcted, and remote myocardium were 1013.5 ± 58.5, 1240.9 ± 55.8 (p < 0.001), and 1062.2 ± 55.8 ms (p = 0.169), respectively, while the mean post-contrast T1 values were 466.7 ± 26.8, 399.1 ± 21.3, and 585.2 ± 21.3 ms, respectively (p < 0.001). The mean MVO areas on LGE, native, and post-contrast T1 maps were 134.1 ± 81.2, 133.7 ± 80.4, and 117.1 ± 53.3 mm², respectively. The median (interquartile range) MVO areas on LGE, native, and post-contrast T1 maps were 128.0 (58.1–215.4), 110.5 (67.7–227.9), and 143.0 (76.7–155.3) mm², respectively (p = 0.002). Concordance correlation coefficients for the MVO area between LGE and native T1 maps, LGE and post-contrast T1 maps, and native and post-contrast T1 maps were 0.770, 0.375, and 0.565, respectively.

Conclusion

MVO areas were accurately delineated on native T1 maps and showed high concordance with the areas measured on LGE. However, post-contrast T1 maps had low detection rates and underestimated MVO areas. Collectively, native T1 mapping is a useful tool for detecting MVO within the infarcted myocardium.

Frequent Premature Atrial Contractions as a Poor Prognostic Factor in Cryptogenic Stroke Patients with Concomitant Non-Sustained Atrial Tachycardia

In cryptogenic stroke patients, early detection of new-onset atrial fibrillation (AF) and recurrent stroke is required to prevent poor clinical outcomes. Therefore, we investigated the predictors of new-onset AF and recurrent stroke in cryptogenic stroke patients without previously diagnosed AF. In total, 390 patients who were diagnosed with stroke and non-sustained atrial tachycardia (NSAT) on 24-hour Holter monitoring were followed up to assess new-onset AF and recurrent stroke. The 5-year event-free survival as well as the predictors of recurrent stroke or new-onset AF were investigated. Based on receiver operating characteristic analysis, frequent premature atrial contractions (PACs) were defined as PACs >44 beats/day. The median follow-up period was 35 months. The composite event rate was 11.5%. In Kaplan-Meier analysis, the 5-year cumulative incidence of composite events was higher in cryptogenic stroke patients with frequent PACs than in those without frequent PACs. Multivariate analysis revealed that current smoking, increased left atrial volume index, and frequent PACs were poor prognostic predictors of composite event, and frequent PACs were an independent poor prognostic factor of new-onset AF in cryptogenic stroke patients. Therefore, frequent PACs might be associated with poor clinical outcomes (new-onset AF and recurrent stroke) in cryptogenic stroke patients with concomitant NSAT.

Boron difluoride hemicurcuminoid as an efficient far red to near-infrared emitter: toward OLEDs and laser dyes

A hemicurcuminoid boron difluoride complex is used as an emitter in organic light-emitting diodes, showing far red/near-infrared electroluminescence with an external quantum efficiency as high as 2.1%. This dye blended in CBP thin films shows amplified spontaneous emission with a threshold of 22 μJ cm^-2 at 750 nm, making this compound attractive for organic semiconductor lasers operating in the near-infrared region.

Fabrication of nitrogen-doped nano-onions and their electrocatalytic activity toward the oxygen reduction reaction

Nitrogen-doped nano-onions (NNO) were prepared as electrocatalytic materials for the oxygen reduction reaction (ORR). The nano-onions (NO), spherical graphitic material particles, were prepared by pyrolysis of nanodiamonds (ND). Oxidized NO (ONO) was prepared from NO by a modified Hummers’ method, and this was mixed with urea, followed by pyrolysis, resulting in the formation of NNO. The nitrogen content and molar ratio of nitrogen-containing groups in the NNOs were varied by controlling the oxygen content of ONO to explore the effect of nitrogen content on the ORR activity. The formation of NO was confirmed by Raman spectroscopy, X-ray diffraction analysis, and high-resolution transmission electron microscopy. X-ray photoelectron spectroscopy analyses were conducted to confirm the formation of the NNO and the structures of the nitrogen-containing groups in the NNOs. The ORR activities of the NNOs were investigated using a rotating disk electrode. The NNOs showed a higher onset potential than that of NO, and the ORR activity of the NNO could be improved by increasing the number of active sites (nitrogen-containing groups) in the NNO. In addition, the NNO exhibited better long-term stability and resistance toward methanol crossover in the ORR than the platinum-based catalysts.

Effects of β-Glucan on the Release of Nitric Oxide by Macrophages Stimulated with Lipopolysaccharide

This research analyzed the effect of β-glucan that is expected to alleviate the production of the inflammatory mediator in macrophagocytes, which are processed by the lipopolysaccharide (LPS) of Escherichia. The incubated layer was used for a nitric oxide (NO) analysis. The DNA-binding activation of the small unit of nuclear factor-κB was measured using the enzyme-linked immunosorbent assay-based kit. In the RAW264.7 cells that were vitalized by Escherichia coli (E. coli) LPS, the β-glucan inhibited both the combatant and rendering phases of the inducible NO synthase (iNOS)-derived NO. β-Glucan increased the expression of the heme oxygenase-1 (HO-1) in the cells that were stimulated by E. coli LPS, and the HO-1 activation was inhibited by the tin protoporphyrin IX (SnPP). This shows that the NO production induced by LPS is related to the inhibition effect of β-glucan. The phosphorylation of c-Jun N-terminal kinases (JNK) and the p38 induced by the LPS were not influenced by the β-glucan, and the inhibitory κB-α (IκB-α) decomposition was not influenced either. Instead, β-glucan remarkably inhibited the phosphorylation of the signal transducer and activator of transcription-1 (STAT1) that was induced by the E. coli LPS. Overall, the β-glucan inhibited the production of NO in macrophagocytes that was vitalized by the E .coli LPS through the HO-1 induction and the STAT1 pathways inhibition in this research. As the host immune response control by β-glucan weakens the progress of the inflammatory disease, β-glucan can be used as an effective immunomodulator.

A comparative study of bone mineral density among patients with obstructive lung diseases in Korea

BACKGROUND

Decreased bone mineral density (BMD) in patients with obstructive lung disease (OLD) is well known. However, the relationship between BMD and asthma and chronic obstructive pulmonary disease (COPD) overlap syndrome (ACOS) is not yet known.

OBJECTIVE

To determine the relationship between ACOS and decreased BMD.

DESIGN

We evaluated the relationship between OLD phenotypes and decreased BMD in subjects from the Korean National Health and Nutrition Survey IV and V (2008-2011). Data on 979 subjects who underwent spirometry and dual-energy X-ray absorptiometry were included in the study.

RESULTS

Patients with ACOS had lower femur, femur neck and lumbar T-scores than those with COPD (P = 0.048, P = 0.001 and P = 0.002, respectively). On multivariate logistic regression analysis, the ACOS group had a two-fold higher risk of developing osteopenia and low BMD compared to the COPD group (OR 1.960, 95%CI 1.011-3.800, P = 0.046; OR 1.974, 95%CI 1.019-3.824, P = 0.044).

CONCLUSION

The rate of bone loss differed among subjects with the asthma, COPD and ACOS OLD phenotypes. In particular, patients with ACOS had a higher risk of developing osteopenia and low BMD than those with COPD.

Left Ventricular Filling Pressure as Assessed by the E/e' Ratio Is a Determinant of Atrial Fibrillation Recurrence after Cardioversion

PURPOSE

Left ventricular (LV) filling pressure affects atrial fibrillation (AF) recurrence. We investigated the relationship between diastolic dysfunction and AF recurrence after cardioversion, and whether LV filling pressure was predictive of AF recurrence.

MATERIALS AND METHODS

Sixty-six patients (mean 58±12 years) with newly diagnosed persistent AF were retrospectively enrolled. We excluded patients with left atrial (LA) diameters larger than 50 mm, thereby isolating the effect of LV filling pressure. We evaluated the differences between the patients with (group 1) and without AF recurrence (group 2).

RESULTS

Group 1 showed increased LA volume index (LAVI) and E/e' compared to group 2 (p<0.05). During a mean follow-up period of 25±19 months, AF recurrence after cardioversion was 60.6% (40/66). The area under the receiver operating characteristics curve of E/e' for AF recurrence was 0.780 [95% confidence interval (CI): 0.657-0.903], and the optimal cut-off value of the E/e' was 9.15 with 75.0% of sensitivity and 73.1% of specificity. A Kaplan-Meier survival curve showed that the cumulative recurrence-free survival rate was significantly lower in patients with higher LV filling pressure (E/e'>9.15) compared with patients with lower LV filling pressure (E/e'≤9.15) (log rank p=0.008). Cox regression analysis revealed that E/e' [hazards ratio (HR): 1.100, 95% CI: 1.017-1.190] and LAVI (HR: 1.042, 95% CI: 1.002-1.084) were independent predictors for AF recurrence after cardioversion.

CONCLUSION

LV filling pressure predicts the risk of AF recurrence in persistent AF patients after cardioversion.

LAMC2 enhances the metastatic potential of lung adenocarcinoma

Lung cancer is the number one cancer killer, and metastasis is the main cause of high mortality in lung cancer patients. However, mechanisms underlying the development of lung cancer metastasis remain unknown. Using genome-wide transcriptional analysis in an experimental metastasis model, we identified laminin γ2 (LAMC2), an epithelial basement membrane protein, to be significantly upregulated in lung adenocarcinoma metastatic cells. Elevated LAMC2 increased traction force, migration, and invasion of lung adenocarcinoma cells accompanied by the induction of epithelial-mesenchymal transition (EMT). LAMC2 knockdown decreased traction force, migration, and invasion accompanied by EMT reduction in vitro, and attenuated metastasis in mice. LAMC2 promoted migration and invasion via EMT that was integrin β1- and ZEB1-dependent. High LAMC2 was significantly correlated with the mesenchymal marker vimentin expression in lung adenocarcinomas, and with higher risk of recurrence or death in patients with lung adenocarcinoma. We suggest that LAMC2 promotes metastasis in lung adenocarcinoma via EMT and may be a potential therapeutic target.

Electro-optic switching in phase-discontinuity complementary metasurface twisted nematic cell

Electro-optic switching of refraction is experimentally demonstrated in a phase-discontinuity complementary metasurface twisted nematic cell. The phase-discontinuity complementary metasurface is fabricated by focused-ion-beam milling, and a twisted nematic cell is constructed with complementary V-shape slot antenna metasurface. By application of an external voltage, switching is achieved between ordinary refraction and extraordinary refraction satisfying the generalized Snell's law. It has a strong implication for applications in spatial light modulation and wavelength division multiplexer/demultiplexer in a near-IR spectral range.

Development and evaluation of a novel taekwondo chest protector to improve mobility when performing axe kicks

The axe kick, in Olympic style taekwondo, has been identified as the most popular scoring technique aimed to the head during full contact competition. The first purpose of this study was to identify and investigate design issues with the current World Taekwondo Federation approved chest protector. A secondary purpose was to develop a novel chest protector addressing the identified design issues and to conduct a biomechanical analysis. Fifteen male elite Taekwondo players were selected to perform three different styles of the axe kick, i.e., front, in-out, and out-in axe kick five times each for a total of 45 kicks. Two-way repeated measures ANOVA showed significant differences between the novel and existing chest protector conditions for vertical height of the toe, downward kicking foot speed, hip flexion angle and ipsilateral shoulder flexion extension range of motion (ROM) (p < 0.05). There were no significant differences between the control condition (no chest protector) and the novel chest protector condition for these variables (p > 0.05). These results indicate that the novel chest protector interferes less with both the lower and upper limbs during the performance of the axe kick and provides a more natural, free-moving alternative to the current equipment used.

Unusual maternal uniparental isodisomic x chromosome mosaicism with asymmetric y chromosomal rearrangement

Infertile men with azoospermia commonly have associated microdeletions in the azoospermia factor (AZF) region of the Y chromosome, sex chromosome mosaicism, or sex chromosome rearrangements. In this study, we describe an unusual 46,XX and 45,X mosaicism with a rare Y chromosome rearrangement in a phenotypically normal male patient. The patient's karyotype was 46,XX[50]/45,X[25]/46,X,der(Y)(pter→q11.222::p11.2→pter)[25]. The derivative Y chromosome had a deletion at Yq11.222 and was duplicated at Yp11.2. Two copies of the SRY gene were confirmed by fluorescence in situ hybridization analysis, and complete deletion of the AZFb and AZFc regions was shown by multiplex-PCR for microdeletion analysis. Both X chromosomes of the predominant mosaic cell line (46,XX) were isodisomic and derived from the maternal gamete, as determined by examination of short tandem repeat markers. We postulate that the derivative Y chromosome might have been generated during paternal meiosis or early embryogenesis. Also, we suggest that the very rare mosaicism of isodisomic X chromosomes might be formed during maternal meiosis II or during postzygotic division derived from the 46,X,der(Y)/ 45,X lineage because of the instability of the derivative Y chromosome. To our knowledge, this is the first confirmatory study to verify the origin of a sex chromosome mosaicism with a Y chromosome rearrangement.

Gender and age differences in the impact of overweight on obesity-related quality of life among Korean adults

SUMMARY

OBJECTIVE

To investigate gender and age difference in impact of overweight on health-related quality of life (HRQOL) among Korean adults.

METHODS

Cross-sectional obesity-related quality of life (QOL) scores were measured by a Korean obesity-related QOL scale (KOQOL) from 448 Korean adults aged 20-80 years. A body mass index (BMI) was categorized with normal-weight as BMI < 23 kg/m(2), overweight as BMI ≥ 23 kg/m(2) based on the alternative cutoff points for Asians. Each gender was respectively stratified by median age, 45 years for men and 50 years for women, to examine the obesity-related QOL by age groups.

RESULTS

Women had a poorer obesity-related QOL compared to men (p < 0.001). In the younger age group, overweight women had a poorer obesity-related QOL compared with normal-weight women (p < 0.001), however normal-weight and overweight men showed no difference in obesity-related QOL. In the older age group, overweight men showed better QOL on the domains of work-related and psychosocial health than those for normal-weight men, but overweight women still suffered from work-related and routine life QOL.

CONCLUSIONS

This study showed the impact of overweight on obesity-related QOL was different for gender and age group. We should consider the results to manage weight in overweight persons.

Reflection resonance switching in metamaterial twisted nematics cell

Electric switching of reflection resonances at near-IR spectral range is experimentally demonstrated in a reflective metamaterial twisted nematic liquid crystal cell. Reflective metamaterial composed of nano-sized double-split ring resonator aperture is fabricated by a focused ion beam milling. Two-fold rotational symmetry of double-split ring resonators allows for two orthogonal polarization-dependent reflection resonances in the reflective metamaterial. With an external voltage of 10V across 12μm cell gap, a full switching is achieved between two reflection resonances. Dynamic measurements show the time constants of switch-on and switch-off are in the order of 100ms and 10ms, respectively.

Inter-study reproducibility of cardiovascular magnetic resonance tagging

BACKGROUND

The aim of this study is to determine the test-retest reliability of the measurement of regional myocardial function by cardiovascular magnetic resonance (CMR) tagging using spatial modulation of magnetization.

METHODS

Twenty-five participants underwent CMR tagging twice over 12 ± 7 days. To assess the role of slice orientation on strain measurement, two healthy volunteers had a first exam, followed by image acquisition repeated with slices rotated ±15 degrees out of true short axis, followed by a second exam in the true short axis plane. To assess the role of slice location, two healthy volunteers had whole heart tagging. The harmonic phase (HARP) method was used to analyze the tagged images. Peak midwall circumferential strain (Ecc), radial strain (Err), Lambda 1, Lambda 2, and Angle α were determined in basal, mid and apical slices. LV torsion, systolic and early diastolic circumferential strain and torsion rates were also determined.

RESULTS

LV Ecc and torsion had excellent intra-, interobserver, and inter-study intra-class correlation coefficients (ICC range, 0.7 to 0.9). Err, Lambda 1, Lambda 2 and angle had excellent intra- and interobserver ICC than inter-study ICC. Angle had least inter-study reproducibility. Torsion rates had superior intra-, interobserver, and inter-study reproducibility to strain rates. The measurements of LV Ecc were comparable in all three slices with different short axis orientations (standard deviation of mean Ecc was 0.09, 0.18 and 0.16 at basal, mid and apical slices, respectively). The mean difference in LV Ecc between slices was more pronounced in most of the basal slices compared to the rest of the heart.

CONCLUSIONS

Intraobserver and interobserver reproducibility of all strain and torsion parameters was excellent. Inter-study reproducibility of CMR tagging by SPAMM varied between different parameters as described in the results above and was superior for Ecc and LV torsion. The variation in LV Ecc measurement due to altered slice orientation is negligible compared to the variation due to slice location.

TRIAL REGISTRATION

This trial is registered as NCT00005487 at National Heart, Lung and Blood institute.

Isorhamnetin inhibits Prevotella intermedia lipopolysaccharide-induced production of interleukin-6 in murine macrophages via anti-inflammatory heme oxygenase-1 induction and inhibition of nuclear factor-κB and signal transducer and activator of transcription 1 activation

BACKGROUND AND OBJECTIVE

Interleukin-6 (IL-6) is a key proinflammatory cytokine that has been considered to be important in the pathogenesis of periodontal disease. Therefore, host-modulatory agents directed at inhibiting IL-6 appear to be beneficial in terms of attenuating periodontal disease progression and potentially improving disease susceptibility. In the current study, we investigated the effect of the flavonoid isorhamnetin on the production of IL-6 in murine macrophages stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen implicated in inflammatory periodontal disease, and its mechanisms of action.

MATERIAL AND METHODS

Lipopolysaccharide from P. intermedia ATCC 25611 was isolated using the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time PCR to quantify IL-6 and heme oxygenase-1 (HO-1) mRNA expression. The expression of HO-1 protein and the levels of signaling proteins were monitored using immunoblot analyses. The DNA-binding activity of nuclear factor-κB (NF-κB) was analyzed using ELISA-based assay kits.

RESULTS

Isorhamnetin significantly down-regulated P. intermedia LPS-induced production of IL-6 as well as its mRNA expression in RAW264.7 cells. Isorhamnetin up-regulated the expression of HO-1 at both gene transcription and translation levels in cells stimulated with P. intermedia LPS. In addition, inhibition of HO-1 activity by tin protoporphyrin IX blocked the inhibitory effect of isorhamnetin on IL-6 production. Isorhamnetin failed to prevent LPS from activating either c-Jun N-terminal kinase or p38 pathways. Isorhamnetin did not inhibit NF-κB transcriptional activity at the level of inhibitory κB-α degradation. Isorhamnetin suppressed NF-κB signaling through inhibition of nuclear translocation and DNA binding activity of NF-κB p50 subunit and attenuated signal transducer and activator of transcription 1 signaling.

CONCLUSION

Although further research is required to clarify the detailed mechanism of action, we propose that isorhamnetin may contribute to blockade of the host-destructive processes mediated by IL-6 and could be a highly efficient modulator of the host response in the treatment of inflammatory periodontal disease. Further research in animal models of periodontitis is required to better evaluate, the potential of isorhamnetin as a novel agent for treating periodontal disease.

Fabrication of polarization-dependent reflective metamaterial by focused ion beam milling

By focused ion beam milling, we fabricated near-IR reflective metamaterials consisting of nano-aperture arrays. Optimum parameters of ion beam current and accelerating voltage in the fabrication process are obtained. Nano-apertures constituting reflective metamaterial are successfully milled, and possess a reflective resonance in the near-IR spectral range. With a double-split-ring resonator structure for the nano-aperture, the intensity reflection at resonance is rendered polarization dependent. It is found that the point group symmetry of the nano-aperture array determines the amount of anisotropy in the intensity reflection. Finite-difference time-domain simulation was adopted to identify details of nano-aperture metastructures transferred from nano-aperture patterns by the focused ion beam milling.

Blocking the immunosuppressive axis with small interfering RNA targeting interleukin (IL)-10 receptor enhances dendritic cell-based vaccine potency

Improving dendritic cell (DC) functions is highly promising for therapeutic intervention of diverse diseases, including cancer. Immunosuppressive cytokines such as interleukin (IL)-10 produced by DCs themselves (autocrine) and other regulatory immune cells (paracrine) down-regulate functional profiles of DCs through specific cell surface receptors such as IL-10R. Here, we tried to improve DC functions using small interfering RNA (siRNA) technology to block an IL-10R-mediated immunosuppressive axis. DCs modified with siRNA targeting against IL-10R or IL-10 (DC/siIL-10R or DC/siIL-10) led to up-regulation of major histocompatibility complex (MHC) class II, CD40 co-stimulatory molecule, and IL-12 proinflammatory cytokine after lipopolysacharide (LPS) stimulation compared to DC/siGFP. Notably, the LPS-induced functional profiles of DC/siIL-10R were strongly resistant to the addition of recombinant IL-10, which mimicked paracrine IL-10. In contrast, those of DC/siIL-10 were reversed by adding exogenous IL-10. Consistently, DC/siIL-10R generated more human papilloma virus (HPV) E7-specific CD8(+) T cells and stronger anti-tumour effects against E7-expressing TC-1 tumour cells in vaccinated mice than DC/siGFP, as well as DC/siIL-10. Taken together, these results provide the groundwork for future clinical translation of siRNA-mediated strategy targeting IL-10R to enhance DC-based vaccine potency.

Temporal dynamics in wheat grain zinc distribution: is sink limitation the key?

BACKGROUND AND AIMS

Enhancing the zinc (Zn) concentration in wheat (Triticum aestivum) grain is a breeding objective in order to improve human Zn nutrition. At enhanced plant Zn uptake, grain Zn levels do not increase proportionally and within the grain the endosperm Zn levels remain below grain Zn levels. This study analysed the temporal dynamics of Zn concentrations in grain tissues during grain filling to find major bottlenecks.

METHODS

Plants of two cultivars were grown at 1 and 5 mg Zn kg(-1) soil. Individual panicles were harvested 7, 14, 24 or 34 d after their flowering or at maturity and seeds were dissected into constituting tissues, which were analysed for Zn and other minerals.

KEY RESULTS

The Zn concentration of the crease was found to increase five- to nine-fold between 7 and 34 d after anthesis, while that of the endosperm decreased by 7 and 45 % when grown at 1 or 5 mg Zn kg(-1), respectively. The Zn turnover rate (d(-1)) in the crease tissues was either independent of the Zn application level or higher at the lower Zn application level, and the Zn concentration increased in the crease tissues with time during grain filling while the turnover rate gradually decreased.

CONCLUSIONS

There is significant within-seed control over Zn entering the seed endosperm. While the seed crease Zn concentration can be raised to very high levels by increasing external Zn supply, the endosperm Zn concentrations will not increase correspondingly. The limited transfer of Zn beyond the crease requires more research to provide further insight into the rate-determining processes and their location along the pathway from crease to the deeper endosperm.

Metabolic syndrome and quality of life (QOL) using generalised and obesity-specific QOL scales

OBJECTIVES

We investigated the association between metabolic syndrome (MS) and health-related quality of life (HRQOL) assessed using generalised and obesity-specific QOL instruments.

METHODS

We recruited 456 outpatients [age: 19-81 years, body mass index (BMI): 16.3-36.7 kg/m2] in the primary care division from 12 general hospitals in Korea. HRQOL was measured using EuroQol comprising the health states descriptive system (EQ-5D) and visual analogue scale (EQ-VAS) as a general instrument. The Korean Obesity-related QOL scale (KOQOL) composed of six domains was used as a disease-specific QOL instrument. MS was defined on the basis of International Diabetes Federation (IDF) criteria with Korean-specific waist circumference cutoffs (men: 90 cm, women: 85 cm).

RESULTS

Subjects with MS displayed significantly higher impairment of EQ-5D and KOQOL. Binary logistic regression analysis of MS patients with controls for age, gender, smoking, alcohol, exercise, education, income, marital status and medication history disclosed odds ratio (OR) values of 2.13 (1.33-3.41) for impaired total KOQOL, 2.07 (1.31-3.27) for impaired physical health, 1.63 (1.03-2.60) for impaired work-related health, 2.42 (1.45-4.04) for impaired routine life, 2.08 (1.27-3.40) for impaired sexual life and 2.56 (1.59-4.11) for diet distress. Among the EQ-5D dimensions, only pain/discomfort displayed a significantly increased OR of 1.60 (1.01-2.56) in MS group.

CONCLUSIONS

Subjects with MS displayed a significantly impaired HRQOL compared with those without MS. MS and HRQOL were more strongly associated in obesity-specific QOL than in generalised QOL.

Effect of Geometric Remodeling on Left Ventricular Longitudinal Contractile Reserve in Patients with Hypertension

Left ventricular hypertrophy (LVH) is associated with a reduction of subendocardial coronary flow reserve, which may be associated with abnormal myocardial longitudinal function during exercise. To test this hypothesis, 182 hypertensive patients underwent multistage supine bicycle exercise testing. Patients were classified as follows: patients with normal geometry (group 1, n = 116), concentric remodeling (group 2, n = 31), or LVH (group 3, n = 31). The results showed that the ratio of E/E', an index of left ventricular (LV) filling pressure, was significantly elevated in the LVH group at rest and during exercise. At rest, the mitral annular systolic velocity (S') was similar between the three groups at rest, whereas S' during exercise was significantly lower in the LVH group. The magnitude of change in S' during exercise was also significantly lower in the LVH group. Multiple linear regression analysis showed that peak double product (beta = 0.208, P = .006) and LV mass index (beta = -0.158, P = .028) were independently associated with LV longitudinal contractile reserve. Also, multiple linear regression analysis showed that changes in S' from baseline to peak were independently associated with exercise duration (beta = 0.123, P = .041) when controlled for age, male gender, baseline E', peak systolic blood pressure, and LV mass index. The results from this study demonstrate that LVH was significantly associated with abnormal LV longitudinal contractile reserve in hypertensive patients.

Association of extracellular cleavage of E-cadherin mediated by MMP-7 with HGF-induced in vitro invasion in human stomach cancer cells

BACKGROUND

Proteolytic shedding of the ectodomain of a variety of transmembrane proteins, including cell-to-cell adhesion molecules, has been observed in solid cancers. We have investigated whether extracellular cleavage of E-cadherin mediated by matrix metalloproteinase-7 (MMP-7) is involved in hepatocyte growth factor (HGF) induced in vitro invasion in stomach cancer cells.

METHODS

The effects of HGF on the expression of E-cadherin/beta-catenin and MMP-7 at both the protein and mRNA levels were assessed in stomach cancer cells, NUGC-3 and MKN-28, and in cells in which the expression of MMP-7 was downregulated by transfection with a MMP-7 short hairpin RNA plasmid.

RESULTS

Treatment with HGF increased the extracellular cleavage of E-cadherin and the release of MMP-7 and reduced the level of E-cadherin in a dose- and time-dependent manner. HGF treatment repressed the phosphorylation of beta-catenin in a Triton-soluble fraction, but enhanced this phosphorylation in a Triton-insoluble fraction. The association of E-cadherin with beta-catenin was decreased by HGF treatment in the Triton-soluble fraction. In addition, treatment of MMP-7 short hairpin RNA transfected NUGC-3 cells with HGF resulted in no extracellular cleavage of E-cadherin and also decreased the in vitro cell invasion.

CONCLUSIONS

These results suggest that incubation with HGF mediated the release of MMP-7, resulting in extracellular cleavage of E-cadherin from stomach cancer cells. This might be a key mechanism in HGF-induced in vitro invasion and metastasis.

Non-dippers are associated with adverse cardiac remodeling and dysfunction (R1)

BACKGROUND

Non-dippers are known to carry a high risk of cardiovascular complications due to higher cumulative 24-h pressure load over time. In this study, we hypothesized that non-dippers would be associated with adverse cardiac remodeling and left ventricular (LV) dysfunction in treated hypertensive patients.

MATERIALS AND METHODS

A total of 150 outpatients treated with antihypertensive drugs for at least 1 year were enrolled. The patients were classified as non-dippers if their daytime ambulatory systolic and diastolic BP did not decrease by at least 10% during the night. LV diastolic function was assessed by measuring mitral inflow velocity (E), early diastolic mitral annulus tissue velocity (E') and LV systolic function was assessed by measuring systolic tissue velocity (S'), longitudinal systolic strain and strain rate.

RESULTS

The Cornell voltage product, LA volume index and LV mass index was significantly higher in non-dippers. Early diastolic mitral annulus tissue velocity (E') was lower and E/E' was higher in non-dippers suggestive of diastolic dysfunction. Systolic tissue velocity (S'), systolic strain and strain rate were significantly lower in non-dippers suggestive of systolic dysfunction. The non-dipper status, controlled for age, sex and LV mass index showed significant correlation with E' (beta=-0.203, P=0.002), E/E' (beta=0.354, P<0.001), S' (beta=-0.231, P=0.002), strain (beta=-0.162, P=0.040) and strain rate (beta=-0.186, P=0.015).

CONCLUSIONS

This study showed the non-dippers in treated hypertensive patients were associated with adverse cardiac remodeling and early LV dysfunction. Further studies to demonstrate the long term prognostic significance of this finding is warranted.

Morphometric Studies on the Testis of Korean Ring-necked Pheasant (Phasianus colchicus karpowi) during the Breeding and Non-breeding Seasons

The purpose of this study was to obtain detailed quantitative information on all cell types in the testis interstitium of Korean ring-necked pheasants and to combine these data with changes in the steroidogenic function of the testis during the breeding and non-breeding seasons. For animals collected during the breeding season, their testis weights, sperm production, serum testosterone levels and leuteinizing hormone (LH)-stimulated testosterone secretion were significantly (p < 0.01) increased compared to the non-breeding season. Testes of the pheasants during the non-breeding season displayed a 98% reduction in testis volume that was associated with a decrease in the absolute volume of seminiferous tubules (98% reduction), tubular lumen (100%), interstitium (90%), blood vessels (84%), lymphatic spaces (97%), Leydig cells (79%), mesenchymal cells (51%) and myoid cells (61%) compared to the breeding season. The numbers of Leydig cells, mesenchymal cells and myoid cells per testis in the breeding season were much higher than in the non-breeding season. Although the mean volume of a Leydig cell was 74% lower in the non-breeding season, the mean volumes of myoid and mesenchymal cells remained unchanged. These results demonstrate that there are striking differences in the testicular structure of the Korean ring-necked pheasant during the breeding and non-breeding seasons. Every structural parameter of the Leydig cell was positively correlated with both testosterone serum levels and LH-stimulated testosterone secretion. The correlation of changes in hormonal status with the morphometric alterations of Leydig cells suggests that the Korean-ring necked pheasant may be used as a model to study structure-function relationships in the avian testis.

Assessment of extent of myocardial ischemia in patients with non-ST elevation acute coronary syndrome using serum B-type natriuretic peptide level

Since B-type natriuretic peptide (BNP) concentration has been shown by recent studies to be elevated in patients presenting acute coronary syndrome (ACS) even in the absence of overt heart failure, other mechanisms for elevating plasma BNP (p-BNP) concentrations may be suggested to exist. We have studied the correlation between p-BNP level and the extent of myocardial ischemia (EMI) in non-ST elevation (NSTE) ACS and evaluated the BNP level as an objective marker of EMI. In 204 patients with NSTE ACS, we estimated the EMI by the echocardiographic wall motion score index (WMSI) and the coronary angiographic Gensini score. As the positive control group, 44 patients with stable angina were enrolled into the study. We compared their initial p-BNP levels with WMSI and the Gensini score. Additionally, peak troponin-T level was compared with p-BNP level in NSTE myocardial infarction (MI) patients. Using the multiple regression analysis, adjustments for age, left ventricle (LV) wall stress, LV mass amount and ejection fraction (EF) were made. Patients with LVEF < 45% or age > 75 years or underlying diseases that could elevate BNP levels were excluded from the study. P-BNP level was increased in NSTE ACS patients compared with stable angina patients (133.9 +/- 87.4 vs. 12.2 +/- 9.2 pg/ml, p < 0.05). P-BNP levels were found to correlate with WMSI and the Gensini score in unstable angina (r=0.519, p < 0.01; r=0.680, p < 0.01) and NSTEMI (r=0.716, p < 0.01; r=0.684, p < 0.01) patients, respectively. Additionally, p-BNP levels correlated with the peak troponin-T level in patients with NSTEMI (r=0.700, p < 0.01). P-BNP level might be a useful marker in the assessment of EMI.

Upregulation of extracellular matrix metalloproteinase inducer (EMMPRIN) and gelatinases in human atherosclerosis infected with Chlamydia pneumoniae: the potential role of Chlamydia pneumoniae infection in the progression of atherosclerosis

Chlamydia pneumoniae infection implicated as an important etiologic factor of atherosclerosis, especially in coronary artery disease (CAD), was found in vitro to be associated with the induction of matrix metalloproteinases (MMPs). An extracellular matrix metalloproteinase inducer (EMMPRIN)/ membrane-type 1 matrix metalloproteinase (MT1-MMP) system which induces and activates MMPs, is suggested to be functional and were upregulated in the failing myocardium. However, the upstream regulation of MMPs by C. pneumoniae within atheroma itself remains unclear. We evaluated the seroepidemiologic study of C. pneumoniae infection in CAD patients (n= 391) and controls (n=97) and performed histopathological and in vitro analysis in atherosclerotic vascular tissues obtained from patients with seropositive to C. pneumoniae (n=20), by using immunochemistry for C. pneumoniae, EMMPRIN/MT1-MMP, MMP-2, and MMP-9. The seropositive rates of both anti-C. pneumoniae IgG and IgA were 56.7% in CAD group and 43.3% in control group (P=0.033). Seropositive rate was increased in subgroups of CAD patients without conventional coronary risk factors compared to those with conventional risk factors. Immunoreactivities of EMMPRIN, MT1-MMP, MMP-2, and MMP-9 were increased in the atheromatous plaque itself, predominantly in immunoreactive macrophages/mononuclear cells to C. pneumoniae. Furthermore, Western blot analysis showed that EMMPRIN and MMP-2 were detected more prominently in atherosclerotic tissues infected with C. pneumoniae compared to control tissues. Zymographic analysis revealed that activities of MMP-2 and MMP-9 were more increased in atherosclerotic tissues infected with C. pneumoniae compared to control tissues. The present study demonstrated upstream regulation of MMPs can be induced by C. pneumoniae within atheromatous plaque itself. These findings help to understand the potential role of C. pneumoniae in the progression of atherosclerosis.

Generation of the dominant-negative mutant of hArpNbeta: a component of human SWI/SNF chromatin remodeling complex

hArpNbeta, an actin-related protein located within the nucleus, is a subunit of the human SWI/SNF chromatin remodeling complex. hArpNbeta has been proposed to regulate the assembly and activity of the hSWI/SNF complex. Sequence comparisons of the potential ArpN homologs with beta-actin showed that the ArpNs have the divergent subdomains Ib and IIb in addition to the unique N-terminal short insert, MS(G/A)-(V/L)YGG. Since the proposed function of hArpNbeta requires more than two distinct but concurrently operating surfaces, we examined whether the disruption of one operating surface of hArpNbeta results in dominant-negative phenotype. When overexpressed in HeLa or 293T cells, the subdomain Ib or IIb hybrids, in which the subdomain Ib or IIb of hArpNbeta was replaced with that of beta-actin, respectively, showed no effect on cell survival. On the other hand, the overexpression of the N-terminal deletion mutant of hArpNbeta resulted in cell death probably through apoptotic process. These results indicate that the proper function of hArpNbeta is essential for cell survival in human cells. Furthermore, they suggests the possibility that the N-terminal short sequence is indispensable for the chromatin remodeling activity or the assembly of the hSWI/SNF complex after the binding of hArpNbeta with functionally essential partner proteins.

CD99 expression is positively regulated by Sp1 and is negatively regulated by Epstein-Barr virus latent membrane protein 1 through nuclear factor-kappaB

Epstein-Barr virus (EBV)-encoded latent membrane protein-1 (LMP1) is highly expressed in Hodgkin and Reed-Sternberg (H-RS) cells from patients with EBV-associated Hodgkin disease. It was previously demonstrated that CD99 can be negatively regulated by LMP1 at the transcriptional level, and the decreased expression of CD99 in a B lymphocyte cell line generates H-RS-like cells. In this study, detailed dissection of the CD99 promoter region was performed to search regulatory factor(s) involved in the expression of the gene. Using various mutant constructs containing deletions in the promoter region, it was revealed that the maximal promoter activity was retained on 5'-deletion to the position -137 from the transcriptional initiation site. Despite the presence of multiple putative Sp1-binding sites in the promoter region, the site located at -95 contributes heavily as a positive cis-acting element to its basal promoter activity. However, on examination of the involvement of the positive-acting Sp1-binding site of the promoter for the repressive activity of LMP1, it appeared to be dispensable. Instead, the repressive effect was mapped to the nuclear factor (NF)-kappaB activation domains in the cytoplasmic carboxyl terminus of LMP1 despite the absence of the NF-kappaB consensus sequences in the CD99 promoter region. Furthermore, the decreased CD99 promoter activity by LMP1 was markedly restored when NF-kappaB activity was inhibited. Taken together, these data suggest that Sp1 activates, whereas LMP1 represses, transcription from the CD99 promoter through the NF-kappaB signaling pathway, and they might aid in the understanding of the molecular mechanisms of viral pathogenesis in EBV-positive Hodgkin disease. (Blood. 2001;97:3596-3604)

Quantitative analysis of the immune response to mouse non-MHC transplantation antigens in vivo: the H60 histocompatibility antigen dominates over all others

Minor histocompatibility Ags (minor H Ags) are substantial impediments to MHC-matched solid tissue and bone marrow transplantation. From an antigenic standpoint, transplantation between MHC-matched individuals has the potential to be remarkably complex. To determine the extent to which the immune response is simplified by the phenomenon of immunodominance, we used peptide/MHC tetramers based on recently discovered minor H Ags (H60, H13, and HY) and monitored in vivo CD8 T cell responses of female C57BL/6 mice primed with MHC-matched, but background-disparate, male BALB.B cells. CD8 T cells against H60 overwhelmed responses to the H13 and HY throughout primary and secondary challenge. H60 immunodominance was an inherent quality, overcoming a lower memory precursor frequency compared with that of H13 and evoking a T cell response with diverse TCRV beta usage. IFN-gamma staining examining congenically defined minor H Ags extended H60 dominance over additional minor H Ags, H28, H4, and H7. These four minor H Ags accounted for up to 85% of the CD8 T cell response, but H60 stood out as the major contributor. These findings show that immunodominance applies to antigenically complex transplantation settings in vivo and that the responses to the H60 minor H Ag dominates in this model. We suggest that immunodominant minor H Ags are those that result from the absence of a self analog.

Immunological characterization of a mucin-associated protein from hamster tracheal epithelial cell culture

Airway mucins are high molecular mass (>10(6) dalton) glycoproteins with various types of associated molecules including glycoproteins, lipoproteins, and lipids. The study of mucin-associated proteins is limited largely due to the lack of specific probes. In this study, we produced a monoclonal antibody, MAbHT10, against a 190-kDa mucin associated-protein by immunizing mice with hamster airway mucin purified in nondissociative condition. Using HT10, the 190-kDa mucin-associated protein was characterized immunologically. The 190-kDa mucin-associated protein is glycoprotein and HT10 recognized carbohydrate containing portion of the protein. The association of 190-kDa protein with mucin is strong enough that heat and detergent treatment is required to dissociate it from mucin as evidenced by gel filtration chromatography, Western blot, enzyme-linked immunoadsorbent assay (ELISA), and co-immunoprecipitation. The expression of the 190-kDa protein is increased with the development of hamster tracheal epithelial cells in culture, but showed differences with the pattern of the regulation of mucin expression. Adenosine triphosphate (ATP), a known strong mucin secretagogue, dose-dependently increased mucin release but caused only marginal increase in the release of the 190-kDa protein. The MAb should be useful in the structural and functional analysis of the 190-kDa mucin-associated proteins in physiological and pathological situations such as chronic airway diseases.

35 GHz ENDOR characterization of the "very rapid" signal of xanthine oxidase reacted with 2-hydroxy-6-methylpurine (13C8): evidence against direct Mo-C8 interaction

Xanthine oxidase is a molybdenum-containing enzyme that catalyzes the hydroxylation of xanthine and a wide variety of other aromatic heterocycles. In the course of the reaction with xanthine and substrates such as 2-hydroxy-6-methylpurine (HMP), the enzyme gives rise to a Mo(V) EPR signal, denoted "very rapid", that arises from an authentic catalytic intermediate. The two alternative catalytic mechanisms proposed for this enzyme differ critically in whether the distance between Mo and C8 of the purine nucleus in this intermediate is short enough to admit a direct bonding interaction. To examine this distance, we have performed 13C ENDOR measurements of the "very rapid" EPR signal generated by xanthine oxidase during reaction with 13C8-HMP. The resulting (13)C8 hyperfine tensor, A = [10.2(1), 7.0(1), 6.5(1)] MHz, is discussed in the framework of a detailed consideration of factors involved in extracting metrical parameters from an anisotropic hyperfine interaction composed of contributions from multiple sources, in particular, the effect of the local contributions from spin density on (13)C8. The analysis presented here gives a Mo...C distance whose value is expected to be ca. 2.7-2.9 A in the "very rapid" intermediates formed with both xanthine and HMP, consistent with plausible bond lengths for a Mo-O-C8 fragment where C8 is a trigonal-planar aromatic carbon. The difference from earlier conclusions is explained. The data thus do not support the existence of a direct Mo-C bond in the signal-giving species. This conclusion supports a mechanism that does not involve such an interaction and which begins with base-assisted nucleophilic attack of the Mo(VI)-OH group on the C-8 of substrate, with concomitant hydride transfer to the Mo=S group to give Mo(IV)-SH; the EPR-active "very rapid" species then forms by one-electron oxidation and deprotonation to yield the EPR-detectable Mo(V)OS(OR) species. We further discuss the complexities and limitations of the semiempirical method used to arrive at these conclusions.

Identification of a nuclear protein ArpN as a component of human SWI/SNF complex and its selective association with a subset of active genes

The hSWI/SNF complex remodels the chromatin structure to modulate gene expression. The hSWI/SNF complex is a multiprotein complex with at least 10 different proteins in mammals. In this study, we identified the 45 kDa subunit of the hSWI/SNF complex as ArpN, an actin-related protein. ArpN has a 36% identity and 50% similarity with the human beta-actin, but cannot be classified into any known class of actin-related proteins. ArpN is exclusively localized within the nucleus and appears as the unbound, chromatin-associated, or nuclear matrix associated forms in the nucleus. In the chromatin immunoprecipitation (ChIP) assay, we found the associations of ArpN with the Ets-2 and c-mycP2 promoter regions in HeLa cells. The promoter regions of the hsp70, cyclophilin, beta-globin, TdT, and cd4 genes, however, were not associated with ArpN. The Ets-2 and c-mycP2 genes are expressed actively in HeLa cells, but beta-globin, TdT, and cd4 genes are inactive. The hsp70 and cyclophilin genes have a feature of stress-inducibility. These selective associations of ArpN with a subset of active genes support the proposition that the requirement of hSWI/SNF complex in gene activation is gene specific.

Genetic changes of hOGG1 and the activity of oh8Gua glycosylase in colon cancer

oh8Gua glycosylase repairs DNA by removing oh8Gua, a highly mutagenic oxidative DNA adduct. Recently, the gene for human oh8Gua glycosylase (hOGG1) was cloned and several mutational types have been reported. However, the implications of such mutations in human cancer have not been clearly demonstrated. To test the involvement of hOGG1 mutation in colon carcinogenesis, we analysed the genetic changes of hOGG1 and the activity of oh8Gua glycosylase in 15 paired normal and tumorous colon specimens. The activity of antioxidant enzymes (catalase and superoxide dismutase (SOD)) and extent of oxidative cellular damage (oh8Gua and malondialdehyde) were also assessed to compare the oxidative status of normal and tumour tissues. An Arg 154 to His mutation was detected in two tumour samples, but not in the corresponding normal tissues. A Ser 326 to Cys mutation (polymorphism) was found in both the normal and tumour tissues of 3 patients. However, neither the Arg 154 to His mutation nor the polymorphism at codon 326 significantly decreased the oh8Gua glycosylase activity. The mean activity of oh8Gua glycosylase was significantly higher in the tumours than in normal tissues (P=0.022). Antioxidant enzyme activities were decreased (catalase; P=0.004 and SOD; P=0.002), and the extent of oxidative damage correspondingly increased in the tumour tissues (oh8Gua; P=0.007 and malondialdehyde; P=0.046). Although the sample size was limited, these results suggest that the somatic mutation or the polymorphism of hOGG1 is less likely to be involved in colon carcinogenesis. Nevertheless, the greater oxidative DNA damage in the tumour tissues, as a possible result of impaired antioxidant activity, implies an important role for oxygen free-radicals in colon carcinogenesis.

T-T interaction during thymic selection

During thymic development, immature thymocytes are selected through the interaction with self peptides loaded on self MHC molecules. Although there is a great deal of debates on how specifically thymocytes recognize self peptides during thymic selection, recent data suggest an important role of peptide diversity in selecting an adequate T-cell repertoire in the thymus. The findings that human T-cells, unlike mouse T-cells, express MHC class II molecules on their surfaces and can play as antigen presenting cells suggesting possible peripheral T-T interaction network has not been intensively studied so far. However, the facts that human thymocytes have surface expression of MHC class II molecules and thymocytes can be selected by thymocytes in in vitro re-aggregation culture system led us to propose a novel hypothesis - "T-T interaction during thymic selection". Our proposition is that peripheral T-T interaction through TCR-derived peptides might reflect the selection process in the thymus and that T-T interaction also plays an important role in thymic selection. This review deals with our thymic T-T interaction hypothesis and its implications on human T-cell development.

Endostatin inhibits endothelial and tumor cellular invasion by blocking the activation and catalytic activity of matrix metalloproteinase

Here we report the inhibition of cellular invasion by a recombinant mouse endostatin and the possible mechanism of the inhibition. Endostatin significantly reduced endothelial as well as tumor cellular invasion into the reconstituted basement membrane in vitro. Gelatin zymographic analysis revealed that the activation of promatrix metalloproteinase-2 (proMMP-2) that was secreted from endothelial cells was blocked upon endostatin treatment. Studies with recombinant MMPs confirmed that endostatin inhibited proMMP-2 activation, mediated by both membrane-type 1 MMP and 4-aminophenylmercuric acetate. Furthermore, enzymatic assays using a peptide substrate demonstrated that endostatin inhibited the catalytic activities of both MMP-2 and membrane-type 1 MMP. Finally, coimmunoprecipitation experiments revealed that endostatin formed a stable complex with proMMP-2. These novel findings would, at least in part, explain the mechanism of the potent antiangiogenic and antitumor activities of endostatin.

Cross-species immunoreactivity of airway mucin as revealed by monoclonal antibodies directed against mucins from human, hamster, and rat

Airway mucin plays crucial role in host-defense and has been implicated in pathophysiology of various airway diseases including asthma and cystic fibrosis. The analysis of airway mucin has been hampered mostly by the lack of specific and efficient methods for the detection of mucin. Recent production of antibodies against airway mucin from several species and also the development of immunoassay procedures make it more efficient to study the airway mucin. However, the cross-species immunoreactivity of antibodies against airway mucin has not been clearly demonstrated and this prompted us to investigate the cross-species immunoreactivity of monoclonal antibodies against human (HM02), hamster (HTA), and rat airway mucin (RT03), which is three most widely used species in the study of mucin. All the monoclonal antibodies (MAbs) used in this study is IgM isotype and recognizes N-acetyl-galactosamine-linked carbohydrate core or backbone portion of airway mucin. In enzyme-linked immunoadsorbent assay (ELISA), Western blot, immunoprecipitation, and immunohistochemical staining experiments, it was demonstrated that human and hamster airway mucin showed strong cross-species immunoreactivity. However, rat airway mucin did not show any cross-species immunoreactivity against human and hamster airway mucin. Endotoxin-induced secretory cell metaplasia and hence the increase in mucin release from hamster airway mucin could be detected with antibodies against hamster and human airway mucin in vivo and in vitro. However, the same increase from rat airway could only be detected with antibody against rat airway mucin but not with antibodies against human and hamster airway mucin. In addition, the increase in mucin release from asthmatic patients could be detected with antibodies against human and hamster airway mucin but not with the antibody against rat airway mucin. The data from the present study implicates that the carbohydrate chain of human and hamster airway mucin, but not that of rat airway mucin, share common antigenic structure. In case of the interspecies use of the antibodies against airway mucin, it would be more desirable to clearly identify the cross-species immunoreactivity otherwise might lead to erroneous results.

Squamous differentiation downregulates Muc1 mucin in hamster tracheal surface epithelial cell

To investigate whether the squamous differentiation of primary hamster tracheal epithelial cell, which is induced by retinoic acid deficiency or chronic PMA treatment, regulates Muc1 expression, we first produced and characterized a monoclonal antibody against hamster tracheal Muc1 mucin using pGEX-Muc1 fusion protein as an antigen and the changes of Muc1 mucin expression was determined by Western blot. Squamous differentiation downregulated the expression of Muc1 mucin from HTSE cells. The decrease in the immunoreactivity of Muc1 mucin was parallel to the decrease in the immunoreactivity of high molecular weight mucin, which is secreted from HTSE cells. The data from the present study implicate a possible role of Muc1 mucin in squamous differentiation of HTSE cells.

Reorganization of myosin and focal adhesion proteins in Swiss 3T3 fibroblasts induced by transforming growth factor beta

Certain types of cells show a dramatic change in cell morphology cultured in the presence of transforming growth factor beta (TGF-beta). To identify cellular components or factors leading to morphological changes, we investigated if any members of cytoskeletal proteins and cell-adhesion molecules were redistributed in TGF-beta-treated Swiss 3T3 fibroblasts by indirect immunofluorescence and Western-blot analysis. Changes in cell morphology became apparent within 12 h of the addition of TGF-beta and new RNA and protein synthesis was necessitated by the changes. While TGF-beta induced reorganization of microfilaments as reported in earlier studies, one of the actin isoforms, alpha actin of smooth muscle, was induced to form stress fibers in Swiss 3T3 cells. It was observed that myosin light chain was relocated from cell periphery to cytoplasmic filamentous structures by TGF-beta treatment, with an increased amount. In addition, the cell-shape change was accompanied by an increase in the level of vinculin and tyrosine phosphorylation at focal adhesions. These results suggest that new protein synthesis is required for the cell-shape change, and acto-myosin filaments and focal adhesion proteins are involved in the alteration of cell morphology induced by TGF-beta in Swiss 3T3 fibroblasts.