[A comparative study of rigid gas permeable corneal contact lenses versus frame glasses for refractive correction of postoperative aphakic eyes after congenital cataract surgery in infants and children]

Objective: The aim of this paper is to compare the refractive correction effects of rigid gas permeable contact lenses (RGPCL) and spectacle correction in children with aphakia after congenital cataract surgery. Methods: This was a prospective non-randomized controlled trial. Children with aphakic eyes after congenital cataract surgery, who underwent vision correction in the Strabismus and Pediatric Ophthalmology Clinic of Beijing Tongren Hospital affiliated with Capital Medical University from April 2012 to November 2019, were continuously collected. Those who voluntarily chose to wear RGPCL for refractive correction were included in the experimental group. Patients with monocular disease were in trial group 1, and patients with binocular disease were in trial group 2. Patients who chose to wear frame glasses for refractive correction were included in the control group. Patients with monocular disease were in control group 1, and patients with binocular disease were in control group 2. Regional origin, medical history, and family information were collected at the first diagnosis. During the follow-up, adverse reactions occurring during the process of wearing glasses were recorded. The Teller acuity card was used for visual examination to obtain the best-corrected visual acuity and convert it into the logarithm of the minimum resolution angle. The degree of nystagmus was determined according to the amplitude and frequency of nystagmus. Treatment cost, treatment compliance, and the reasons for adopting or not adopting RGPCL were analyzed through a questionnaire completed by the parents of children with RGPCL. Results: A total of 203 children (344 eyes) who underwent congenital cataract surgery were included, including 124 males (210 eyes) and 79 females (134 eyes). The age range was 3 to 36 months. There were 28 cases in the experimental group, including 19 cases in trial group 1 and 9 cases in trial group 2. There were 175 cases in the control group, including 43 cases in control group 1 and 132 cases in control group 2. Except for 6 months of age, the visual acuity of the experimental group was better than that of the control group, and the differences were statistically significant (P<0.05). The visual acuity of children in trial group 1 was better than that of children in control group 1 at the same age. Among them, at 12 months of age [1.54 (1.27, 1.97), 1.84 (0.97, 2.12)], 18 months of age [1.27 (0.97, 1.84), 1.84 (0.97, 2.12)], 24 months of age [1.54 (1.27, 1.84), 1.84 (0.97, 2.12)], and 30 months old [0.97 (0.66, 1.27), 1.54 (0.66, 2.12)], the difference was statistically significant (P<0.001). The visual acuity of children in trial group 2 was better than that in control group 2 at the same age. Among them, at 18 months old [1.27 (0.97, 1.54), 1.27 (0.66, 2.12)], 24 months old [0.97 (0.66, 1.27), 1.27 (0.66, 2.12)], and 30 months old [1.27 (0.66, 2.12)], the difference was statistically significant (P<0.05). The remission rate of nystagmus in the experimental group was 8/9 (8 cases), the remission rate of nystagmus in the control group was 34.40% (32 cases), and the exacerbation rate was 29.03% (27 cases). The average annual cost of the experimental group was 25 125 yuan, and that of the control group was 2 511 yuan. Conclusions: RGPCL is a well-tolerated, safe, and effective treatment for infants and young children. The visual acuity and degree of nystagmus were significantly improved in children who wore RGPCL for aphakia refractive correction after congenital cataract surgery compared with spectacle correction.

Deep Learning Nomogram for the Identification of Deep Stromal Invasion in Patients With Early-Stage Cervical Adenocarcinoma and Adenosquamous Carcinoma: A Multicenter Study

BACKGROUND

Deep stromal invasion (DSI) is one of the predominant risk factors that determined the types of radical hysterectomy (RH). Thus, the accurate assessment of DSI in cervical adenocarcinoma (AC)/adenosquamous carcinoma (ASC) can facilitate optimal therapy decision.

PURPOSE

To develop a nomogram to identify DSI in cervical AC/ASC.

STUDY TYPE

Retrospective.

POPULATION

Six hundred and fifty patients (mean age of 48.2 years) were collected from center 1 (primary cohort, 536), centers 2 and 3 (external validation cohorts 1 and 2, 62 and 52).

FIELD STRENGTH/SEQUENCE

5-T, T2-weighted imaging (T2WI, SE/FSE), diffusion-weighted imaging (DWI, EPI), and contrast-enhanced T1-weighted imaging (CE-T1WI, VIBE/LAVA).

ASSESSMENT

The DSI was defined as the outer 1/3 stromal invasion on pathology. The region of interest (ROI) contained the tumor and 3 mm peritumoral area. The ROIs of T2WI, DWI, and CE-T1WI were separately imported into Resnet18 to calculate the DL scores (TDS, DDS, and CDS). The clinical characteristics were retrieved from medical records or MRI data assessment. The clinical model and nomogram were constructed by integrating clinical independent risk factors only and further combining DL scores based on primary cohort and were validated in two external validation cohorts.

STATISTICAL TESTS

Student's t-test, Mann-Whitney U test, or Chi-squared test were used to compare differences in continuous or categorical variables between DSI-positive and DSI-negative groups. DeLong test was used to compare AU-ROC values of DL scores, clinical model, and nomogram.

RESULTS

The nomogram integrating menopause, disruption of cervical stromal ring (DCSRMR), DDS, and TDS achieved AU-ROCs of 0.933, 0.807, and 0.817 in evaluating DSI in primary and external validation cohorts. The nomogram had superior diagnostic ability to clinical model and DL scores in primary cohort (all P < 0.0125 [0.05/4]) and CDS (P = 0.009) in external validation cohort 2.

DATA CONCLUSION

The nomogram achieved good performance for evaluating DSI in cervical AC/ASC.

LEVEL OF EVIDENCE

3 TECHNICAL EFFICACY: Stage 2.

Intratumoral and peritumoral MRI radiomics nomogram for predicting parametrial invasion in patients with early-stage cervical adenocarcinoma and adenosquamous carcinoma

OBJECTIVE

To develop a comprehensive nomogram based on MRI intra- and peritumoral radiomics signatures and independent risk factors for predicting parametrial invasion (PMI) in patients with early-stage cervical adenocarcinoma (AC) and adenosquamous carcinoma (ASC).

METHODS

A total of 460 patients with IB to IIB cervical AC and ASC who underwent preoperative MRI examination and radical trachelectomy/hysterectomy were retrospectively enrolled and divided into primary, internal validation, and external validation cohorts. The original (Ori) and wavelet (Wav)-transform features were extracted from the volumetric region of interest of the tumour (ROI-T) and 3mm- and 5mm-peritumoral rings (ROI-3 and ROI-5), respectively. Then the Ori and Ori-Wav feature-based radiomics signatures from the tumour (RST) and 3 mm- and 5 mm-peritumoral regions (RS3 and RS5) were independently built and their diagnostic performances were compared to select the optimal ones. Finally, the nomogram was developed by integrating optimal intra- and peritumoral signatures and clinical independent risk factors based on multivariable logistic regression analysis.

RESULTS

FIGO stage, disruption of the cervical stromal ring on MRI (DCSRMR), parametrial invasion on MRI (PMIMR), and serum CA-125 were identified as independent risk factors. The nomogram constructed by integrating independent risk factors, Ori-Wav feature-based RST, and RS5 yielded AUCs of 0.874 (0.810-0.922), 0.885 (0.834-0.924), and 0.966 (0.887-0.995) for predicting PMI in the primary, internal and external validation cohorts, respectively. Furthermore, the nomogram was superior to radiomics signatures and clinical model for predicting PMI in three cohorts.

CONCLUSION

The nomogram can preoperatively, accurately, and noninvasively predict PMI in patients with early-stage cervical AC and ASC.

CLINICAL RELEVANCE STATEMENT

The nomogram can preoperatively, accurately, and noninvasively predict PMI and facilitate precise treatment decisions regarding chemoradiotherapy or radical hysterectomy in patients with early-stage cervical AC and ASC.

KEY POINTS

The accurate preoperative prediction of PMI in early-stage cervical AC and ASC can facilitate precise treatment decisions regarding chemoradiotherapy or radical hysterectomy. The nomogram integrating independent risk factors, Ori-Wav feature-based RST, and RS5 can preoperatively, accurately, and noninvasively predict PMI in early-stage cervical AC and ASC. The nomogram was superior to radiomics signatures and clinical model for predicting PMI in early-stage cervical AC and ASC.

The invasion status of lymphovascular space and lymph nodes in cervical cancer assessed by mono-exponential and bi-exponential DWI-related parameters

AIM

To investigate whether mono-exponential and bi-exponential diffusion-weighted imaging (DWI)-related parameters of the primary tumour can evaluate the status of lymphovascular space invasion (LVSI) and lymph node metastasis (LNM) in patients with cervical carcinoma preoperatively.

MATERIALS AND METHODS

Eighty patients with cervical carcinoma were enrolled, who underwent preoperative multi b-value DWI and radical hysterectomy. They were classified into LVSI(+) versus LVSI(-) and LNM(+) versus LNM(-) according to postoperative pathology. The apparent diffusion coefficient (ADC), pure molecular diffusion (D), pseudo-diffusion coefficient (D∗), and perfusion fraction (f) were calculated from the whole tumour (__whole) and tumour margin (__margin). All parameters were compared between LVSI(+) and LVSI(-) and between LNM(+) and LNM(-). Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic performance of these parameters.

RESULTS

f__margin and D∗__whole showed significant differences in differentiating LVSI(+) from LVSI(-) tumours (p=0.002, 0.008, respectively), while LNM(+) tumours presented with significantly higher ADC__margin than that of LNM(-) tumours (p=0.009). The other parameters were not independent related factors with the status of LVSI or LNM according to logistic regression analysis (p>0.05). The area under the ROC curve of f__margin combined with D∗__whole in discriminating LVSI(+) from LVSI(-) was 0.826 (95% confidence interval [CI]: 0.691-0.961), while ADC__margin in differentiating LNM(+) from LNM(-) was 0.788 (95% CI: 0.648-0.928).

CONCLUSIONS

The parameters generated from mono-exponential and bi-exponential DWI of the primary cervical carcinoma could help discriminate its status regarding LVSI (f__margin and D∗__whole) and LNM (ADC__margin).

Perimenarchal air pollution exposure and menstrual disorders

STUDY QUESTION

What is the association between perimenarchal exposure to total suspended particulate (TSP) in air, menstrual irregularity phenotypes and time to menstrual cycle regularity?

SUMMARY ANSWER

Exposures to TSP during high school are associated with slightly increased odds of menstrual irregularity and longer time to regularity in high school and early adulthood.

WHAT IS KNOWN ALREADY

The menstrual cycle is responsive to hormonal regulation. Particulate matter air pollution has demonstrated hormonal activity. However, it is not known if air pollution is associated with menstrual cycle regularity.

STUDY DESIGN, SIZE, DURATION

Cross sectional study of 34 832 of the original 116 430 women (29.91%) enrolled in 1989 from the Nurses' Health Study II (NHSII). The follow-up rate for this analytic sample was 97.76% at the 1991 survey.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Annual averages of TSP were available for each year of high school attendance. We created three case definitions including high school menstrual irregularity and androgen excess. The time to menstrual cycle regularity was reported by participants as <1 year, 1-2 years, 3-4 years, 5 years or longer, or never on the baseline questionnaire. Odds ratios and 95% confidence intervals (CI) were calculated for 45 μg/m3 increases in TSP exposure, adjusted for risk factors for menstrual irregularity.

MAIN RESULTS AND THE ROLE OF CHANCE

In multivariable adjusted models, we observed that for every 45 μg/m3 increase in average high school TSP there was an increased odds (95%CI) of 1.08 (1.03-1.14), 1.08 (1.02-1.15) and 1.10 (0.98-1.25) for moderate, persistent, and persistent with androgen excess irregularity phenotypes, respectively. TSP was also associated with a longer time to cycle regularity, with stronger results among women with older ages at menarche and those living in the Northeast or the West.

LIMITATIONS, REASONS FOR CAUTION

The outcomes of menstrual regularity and time to cycle regularity were retrospectively assessed outcomes and may be susceptible to recall bias. There is also the potential for selection bias, as women had to live until 2011 to provide addresses.

WIDER IMPLICATIONS OF THE FINDINGS

Temporal exposure to air pollution in the adolescent and early adulthood window may be especially important, given its association with phenotypes of menstrual irregularity. The data from this study agrees with existing literature regarding air pollution and reproductive tract diseases.

STUDY FUNDING/COMPETING INTEREST(S)

Shruthi Mahalingaiah: Reproductive Scientist Development Program HD000849, and a research grant from the Boston University Department of Obstetrics and Gynecology, Stacey Missmer: R01HD57210 from the National Institute of Child Health and Human Development and the Massachusetts Institute of Technology Center for Environmental Health Sciences Translational Pilot Project Program, R01CA50385 from the National Cancer Institute, Jaime Hart and Francine Laden: 5R01ES017017 from the National Institute for Environmental Health Sciences, Jaime Hart: P30 ES00002 from the National Institute for Environmental Health Sciences at the National Institute of Health, The Nurses' Health Study II is supported by infrastructure grant UM1CA176726 from the National Cancer Institute, NIH, U.S. Department of Health and Human Services The authors have no conflicts of interest to declare.

[Association between body weight change during early and middle adulthood and the risk of type 2 diabetes in middle aged and elderly population]

Objective: To examine the association between weight changes during early and middle adulthood and the risk of type 2 diabetes mellitus in middle aged and elderly population. Methods: Based on the Guangzhou Biobank Cohort Study (GBCS), 28 736 residents aged ≥50 years were included in Guangzhou. Multivariate logistic regression was used to analyze the association between body weight changes during early or middle adulthood and age when the heaviest weight reaching the threshold on the risk of type 2 diabetes mellitus in middle age or elderly population. Adjustments on age, smoking, alcohol consumption, physical activity, education level, occupation, district of residence and body mass index etc., were made. Results: The mean age was 64.3 (standard deviation=6.7) years in men and 61.0 (standard deviation=7.0) years in women, with the prevalence rates of diabetes as 13.1% and 13.7% in men and women, respectively. Compared to those with stable body weight, the risk of diabetes increased with weight gain during early and middle adulthood in both men and women (both P values for trend<0.01). Participants who gained more than 20 kg during early and middle adulthood were associated with the highest risk of diabetes in men (OR=2.83, 95%CI:1.99-4.02) and women (OR=3.13, 95%CI: 2.47-3.96). Compared to those who reached the highest weight at age 20, those who reaching the highest weight at 40 to 49 years were associated with the highest risk of diabetes, with OR being 5.32 (95%CI: 1.92-14.8) in men and 3.41 (95%CI: 2.49-4.67) in women, respectively. Weight loss in adulthood was associated with self-reported but not newly diagnosed diabetic cases in both middle and older aged men and women. Conclusion: Weight gain during early and middle adulthood may increase the risk of diabetes in middle and older aged population. The detrimental effect of obesity on diabetes might become significantly visible in the next decades.

Oscillatory EEG activity induced by conditioning stimuli during fear conditioning reflects Salience and Valence of these stimuli more than Expectancy

Imaging studies have described hemodynamic activity during fear conditioning protocols with stimulus trains in which a visual conditioned stimulus (CS+) is paired with an aversive unconditioned stimulus (US, painful laser pulse) while another visual stimulus is unpaired (CS-). We now test the hypothesis that CS Event Related Spectral Perturbations (ERSPs) are related to ratings of CS Expectancy (likelihood of pairing with the US), Valence (unpleasantness) and Salience (ability to capture attention). ERSP windows in EEG were defined by both time after the CS and frequency, and showed increased oscillatory power (Event Related Synchronization, ERS) in the Delta/Theta Windows (0-8Hz) and the Gamma Window (30-55Hz). Decreased oscillatory power (Event Related Desynchronization - ERD) was found in Alpha (8-14Hz) and Beta Windows (14-30Hz). The Delta/Theta ERS showed a differential effect of CS+ versus CS- at Prefrontal, Frontal and Midline Channels, while Alpha and Beta ERD were greater at Parietal and Occipital Channels early in the stimulus train. The Gamma ERS Window increased from habituation to acquisition over a broad area from frontal and occipital electrodes. The CS Valence and Salience were greater for CS+ than CS-, and were correlated with each other and with the ERD at overlapping channels, particularly in the Alpha Window. Expectancy and CS Skin Conductance Response were greater for CS+ than CS- and were correlated with ERSP at fewer channels than Valence or Salience. These results suggest that Alpha ERSP activity during fear conditioning reflects Valence and Salience of the CSs more than conditioning per se.

[Correlation between body fat percentage and general obesity indexes in middle aged and old people in Guangzhou]

Objective: To examine the correlation between body fat percentage (BFP) and general obesity indexes, including body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHR) and calculate the corresponding BFP cutoff values in the middle aged and old people in Guangzhou. The corresponding cut-point of optimal body fat percentage for Guangzhou older population. Methods: Based on the Guangzhou Biobank Cohort Study (GBCS), 3 490 relatively healthy Guangzhou residents aged ≥50 years were selected and were randomly divided into 2 groups. The equations between BFP and BMI, WC, WHR were set up with Curve fitting analysis in one group. The multiple regression analysis was undertaken to establish predictive equations between BFP and BMI, WC, WHR with stepwise model for adding gender, age, physical activity, drinking and smoking. Then, the optimal cut-points of BFP corresponding to BMI, WC and WHR to reflect the degree of obesity were calculated. The equations were then validated with another group. Results: BFP increased with the increase of WHR, WC and BMI. BMI was a better predictor of body fat percentage than WC and WHR. The final regression equation was BFP=(-23.47 -8.87×sex) +2.94× (BMI) - 0.024 × (BMI)²,the coefficient of determination was 0.805. Based on the equation, the BFP corresponding to overweight/obesity (24 kg/m²≤BMI<28 kg/m²) were 24.3% ≤BFP<31.1% in men and 33.2%≤BFP<40.0% in women, respectively. BMI had a better consistency with BFP in identify obesity compared with WC and WHR, obtained the area of ROC 0.909 in men and 0.919 in women respectively. The sensitivity and specificity were 70.3% and 85.5% in men; and 75.2% and 93.0% in women respectively. Conclusion: BFP has a better correlation with BMI. The study results indicated that BFP for middle aged and old males and females in Guangzhou corresponding to overweight/obesity (BMI≥24 kg/m²) were <24.0% and <33.0% respectively.

Effects of selenium on biological and physiological properties of the duckweed Landoltia punctata

Duckweed can be used for bioremediation of selenium (Se) polluted water because of its capability of absorbing minerals from growing media. However, the presence of Se in the media may affect the growth of the duckweed. Landoltia punctata 7449 has been studied for its changes in chemical and biological properties with the presence of Se in the media. The duckweed was cultivated over a 12-day period at different initial concentrations of selenite (Na2 SeO3 ) from 0 to 80 μmol·l(-1) . The growth rate, the organic and total Se contents, the activity of antioxidant enzymes, the photosynthetic pigment contents, the chlorophyll a fluorescence OJIP transient, and the ultrastructure of the duckweed were monitored during the experiment. The results have shown that Se at low concentrations of ≤20 μmol·l(-1) promoted the growth of the L. punctata and inhibited lipid peroxidation. Substantial increases in duckweed growth rate and organic Se content in the duckweed were observed at low Se concentrations. The anti-oxidative effect occurred likely with the increases in guaiacol peroxidase, catalase and superoxide dismutase activities as well as the amount of photosynthetic pigments. However, negative impact to the duckweed was observed when the L. punctata was exposed to high Se concentrations (≥40 μmol·l(-1) ), in which the duckweed growth was inhibited by the selenium. The results indicate that L. punctata 7449 can be used for bioremediation of selenium (Se) polluted water when the Se concentration is ≤20 μmol·l(-1) .

[Effectiveness of bupropion and counseling for smoking cessation]

OBJECTIVE

To evaluate the effectiveness of bupropion for smoking cessation among Chinese smokers at a smoking cessation clinic.

METHODS

A prospective observational study was conducted in a hospital located in Beijing during 2008 and from 28 to 31 October 2014. A total of 287 smokers (265 men and 22 women) were assessed using data from structured questionnaires at baseline and were followed up at 1 and 6 months. Trained physician counselors provided free brief education and individual counseling sessions for all participants at the first visit. A total 131 participants were prescribed bupropion in addition to counseling. The counseling plus bupropion group was compared with the group who underwent counseling without bupropion. Outcomes were self-reported 7-day point prevalence abstinence rates at 1- and 6-month follow-up and continuous abstinence rates at 6-month follow-up. Smoking reduction rates at 1 and 6 months were also measured.

RESULTS

By intention-to-treat analysis, the 7-day point prevalence abstinence rate of the bupropion group at 1 and 6 months was higher than for the counseling-only group: at 1-month follow-up, 26.0% (34/131) vs. 15.4% (24/156), with OR (95% CI) 1.93(1.07-3.46); these rates at 6-month follow-up were 27.8% (35/131) vs. 15.4% (24/156), with OR (95% CI) 2.01(1.12-3.59). The 1-month continuous abstinence rate at 6 months was higher in the bupropion group: 26.0% (34/131) vs. 14.7% (23/156), with OR (95%CI) 2.03(1.12-3.66). Participants in the bupropion group also had a higher smoking reduction rate at 1 month than those in the counseling-only group: 55.0% (72/131) vs. 38.5% (60/156), with OR (95%CI) 1.95 (1.22-3.13).

CONCLUSION

Prescription of bupropion at this smoking cessation clinic was effective in doubling the quitting rates and smoking reduction rates among Chinese smokers.

Survey of duckweed diversity in Lake Chao and total fatty acid, triacylglycerol, profiles of representative strains

Lemnaceae (duckweeds) are widely distributed aquatic flowering plants. Their high growth rate, starch content and suitability for bioremediation make them potential feedstock for biofuels. However, few natural duckweed resources have been investigated in China, and there is no information about total fatty acid (TFA) and triacylglycerol (TAG) composition of duckweeds from China. Here, the genetic diversity of a natural duckweed population collected from Lake Chao, China, was investigated using multilocus sequence typing (MLST). The 54 strains were categorised into four species in four genera, representing 12 distinct sequence types. Strains representing Lemna aequinoctialis and Spirodela polyrhiza were predominant. Interestingly, a surprisingly high degree of genetic diversification within L. aequinoctialis was observed. The four duckweed species revealed a uniform fatty acid composition, with three fatty acids, palmitic acid, linoleic acid and linolenic acid, accounting for more than 80% of the TFA. The TFA in biomass varied among species, ranging from 1.05% (of dry weight, DW) for L. punctata and S. polyrhiza to 1.62% for Wolffia globosa. The four duckweed species contained similar TAG contents, 0.02% mg · DW(-1). The fatty acid profiles of TAG were different from those of TFA, and also varied among the four species. The survey investigated the genetic diversity of duckweeds from Lake Chao, and provides an initial insight into TFA and TAG of four duckweed species, indicating that intraspecific and interspecific variations exist in the content and composition of both TFA and TAG in comparison with other studies.

Differentiation of lung cancers from inflammatory masses with dual-energy spectral CT imaging

RATIONALE AND OBJECTIVES

To investigate the value of dual-energy spectral computed tomography (DESCT) in the quantitative differentiation between pulmonary malignant masses and inflammatory masses.

MATERIALS AND METHODS

This study was an institutional review board-approved study, and written informed consent was obtained from all patients. Sixty patients with 35 lung cancers and 25 inflammatory masses underwent DESCT scan during arterial phase (AP) and venous phase (VP). CT numbers of net enhancement in 70 keV monochromatic images in central and peripheral regions of masses and their differences (dCT) were measured. Iodine concentrations in the two regions were measured and normalized to the aorta as normalized iodine concentrations (NICs). The slopes of spectral attenuation curves (λHU) in the two regions were also calculated. The two-sample t test was used to compare quantitative parameters. Receiver operating characteristic (ROC) curves were generated to calculate sensitivity and specificity.

RESULTS

CT numbers of net enhancement and NICs in central regions, and λHU values both in the central and peripheral region of lung cancers were significantly lower than those of inflammatory masses during AP and VP. On the other hand, the dCT values of lung cancers were higher than that of inflammatory masses. NIC value in the central regions in VP had the highest sensitivity (86%) and specificity (100%) in differentiating malignant masses from inflammatory masses.

CONCLUSIONS

DESCT imaging with quantitative parameters such as CT numbers of 70 keV monochromatic images, NIC, and λHU may be a new method for differentiating lung cancers from inflammatory masses.

Growing duckweed for biofuel production: a review

Duckweed can be utilised to produce ethanol, butanol and biogas, which are promising alternative energy sources to minimise dependence on limited crude oil and natural gas. The advantages of this aquatic plant include high rate of nutrient (nitrogen and phosphorus) uptake, high biomass yield and great potential as an alternative feedstock for the production of fuel ethanol, butanol and biogas. The objective of this article is to review the published research on growing duckweed for the production of the biofuels, especially starch enrichment in duckweed plants. There are mainly two processes affecting the accumulation of starch in duckweed biomass: photosynthesis for starch generation and metabolism-related starch consumption. The cost of stimulating photosynthesis is relatively high based on current technologies. Considerable research efforts have been made to inhibit starch degradation. Future research need in this area includes duckweed selection, optimisation of duckweed biomass production, enhancement of starch accumulation in duckweeds and use of duckweeds for production of various biofuels.

MTA1 promotes cell proliferation via DNA damage repair in epithelial ovarian cancer

We examined whether metastasis-associated gene 1 (MTA1) promotes cell proliferation via DNA damage repair in ovarian cancer. MTA1 was successfully down-regulated using small interfering RNA in the epithelial ovarian cancer cell lines SKOV-3 and OVCAR-3. Cell growth was evaluated through MTT and colony formation assays. Fluorescence-activated cell sorting analysis was used to evaluate the distribution of cells in the cell cycle, and cytotoxicity assays were performed to study cell sensitivity to cisplatin. A neutral comet assay was used to measure levels of ionizing radiation-induced DNA damage in SKOV-3 cells, and Western blot analyses were carried out to examine the expression of key proteins involved in DNA damage repair pathways. MTA1 knockdown markedly inhibited cell growth and led to S phase cell cycle arrest. In addition, MTA1 depletion conferred sensitivity of ovarian cancer cells to cisplatin. Moreover, MTA1 depletion increased the level of ionizing radiation-induced DNA damage and caused irreparable damage, which was illustrated by a remarkable increase and persistent existence of a comet tail as well as protein expression levels of γH2AX, pRPA, and pChk1, all of which play critical roles in DNA repair. Thus, MTA1 promotes the proliferation of epithelial ovarian cancer cells by enhancing DNA repair.

Disappearance of Ising nature in Ca3ZnMnO6 studied by high-field ESR

High-field electron spin resonance measurements of an antiferromagnet Ca3ZnMnO6 isostructure, with the Ising-chain multiferroic Ca3CoMnO6, have been carried out. Two distinct resonance modes were observed below TN = 25 K, which is well explained by conventional antiferromagnetic resonance theory with easy-plane anisotropy. The zero-field spin gap is derived to be about 166 GHz, originating from the easy-plane anisotropy and exchange interaction. Our result suggests that the Dzyaloshinsky-Moriya interaction, which may induce spin canting, is absent. Disappearance of Ising anisotropy in Ca3ZnMnO6 suggests that the Co(4+) ion, as well as the Co-Mn superexchange, plays an important role for the Ising nature in Ca3CoMnO6.

Stable thermophilic anaerobic digestion of dissolved air flotation (DAF) sludge by co-digestion with swine manure

Environmentally sound treatment of by-products in a value-adding process is an ongoing challenge in animal agriculture. The sludge produced as a result of the dissolved air flotation (DAF) wastewater treatment process in swine processing facilities is one such low-value residue. The objective of this study was to determine the fundamental performance parameters for thermophilic anaerobic digestion of DAF sludge. Testing in a semi-continuous stirred tank reactor and in batch reactors was conducted to determine the kinetics of degradation and biogas yield. Stable operation could not be achieved using pure DAF sludge as a substrate, possibly due to inhibition by long-chain fatty acids or to nutrient deficiencies. However, in a 1:1 ratio (w/w, dry basis) with swine manure, operation was both stable and productive. In the semi-continuous stirred reactor at 54.5 degrees Celsius, a hydraulic residence time of 10 days, and an organic loading rate of 4.68 gVS/day/L, the methane production rate was 2.19 L/L/day and the specific methane production rate was 0.47 L/gVS (fed). Maximum specific methanogenic activity (SMA) in batch testing was 0.15 mmoles CH(4) h(-1) gVS(-1) at a substrate concentration of 6.9 gVS L(-1). Higher substrate concentrations cause an initial lag in methane production, possibly due to long-chain fatty acid or nitrogen inhibition.

Inter-comparison of models to estimate radionuclide activity concentrations in non-human biota

A number of models have recently been, or are currently being, developed to enable the assessment of radiation doses from ionising radiation to non-human species. A key component of these models is the ability to predict whole-organism activity concentrations in a wide range of wildlife. In this paper, we compare the whole-organism activity concentrations predicted by eight models participating within the IAEA Environmental Modelling for Radiation Safety programme for a range of radionuclides to terrestrial and freshwater organisms. In many instances, there was considerable variation, ranging over orders of magnitude, between the predictions of the different models. Reasons for this variability (including methodology, data source and data availability) are identified and discussed. The active participation of groups responsible for the development of key models within this exercise is a useful step forward in providing the transparency in methodology and data provenance required for models which are either currently being used for regulatory purposes or which may be used in the future. The work reported in this paper, and supported by other findings, demonstrates that the largest contribution to variability between model predictions is the parameterisation of their transfer components. There is a clear need to focus efforts and provide authoritative compilations of those data which are available.

Implications of urine-to-feces ratio in the thermophilic anaerobic digestion of swine waste

Thermophilic anaerobic digestion of swine manure represents a potential waste treatment technology to address environmental concerns, such as odor emissions and removal of pathogenic microorganisms. However, there are concerns relative to the stability of this process when swine manure is the sole substrate. In this study, the potential of biogas production from swine manure as the sole substrate under thermophilic (50 degrees C) conditions was investigated in the laboratory, to determine whether separation of urine and feces as part of the waste collection process would benefit anaerobic digestion. Effluent from a continuously stirred tank reactor was used as the inoculum for batch tests, in which the substrate contained three different concentrations of urine (urine-free, as-excreted urine-to-feces ratio and double the as-excreted urine-to-feces ratio). Inocula were acclimated to these same urine-to-feces ratios to determine methane production. Results show that both urine-free and as-excreted substrates were not inhibitory to anaerobic inocula. Anaerobic microorganisms can be readily acclimated to substrate with double the as-excreted urine concentration, which contained nitrogen concentrations up to 7.20 g/L. Cumulative methane production reached similar levels in the batch tests, regardless of the substrate urine concentration.

Comparison of the efficacy and tolerability of telmisartan 40 mg vs. enalapril 10 mg in the treatment of mild-to-moderate hypertension: a multicentre, double-blind study in Taiwanese patients

The purpose of this randomised, double-blind, double-dummy, parallel-group study was to evaluate the efficacy and tolerability of telmisartan 40 mg once daily vs. enalapril 10 mg once daily in 147 Taiwanese patients with mild-to-moderate essential hypertension (diastolic blood pressure [DBP] 90-109 mmHg). After 6 weeks' treatment, telmisartan produced a significantly greater reduction from baseline in the primary endpoint of trough seated DBP compared with enalapril 10 mg (11.7 vs. 8.7 mmHg, respectively; p = 0.02). Numerically greater reductions compared with baseline in seated systolic blood pressure (SBP), standing DBP, and standing SBP were achieved with telmisartan compared with enalapril. Also, numerically greater proportions of patients achieved blood pressure control (DBP/systolic blood pressure [SBP] <90/140 mmHg) and responded to treatment (reduction from baseline in trough seated DBP > or = 10 mmHg and/or post-treatment DBP <90 mmHg; reduction from baseline in trough seated SBP > or = 10 mmHg and/or post-treatment SBP <140 mmHg) with telmisartan 40 mg compared with enalapril 10 mg. Although both treatments were well tolerated, the incidence of cough was markedly lower with telmisartan 40 mg (8.5%) than with enalapril 10 mg (18.4%) in this population of Taiwanese hypertensive patients.

Dopamine efflux in nucleus accumbens shell and core in response to appetitive classical conditioning

Dopamine transmission within the nucleus accumbens has been implicated in associative reinforcement learning. We investigated the effect of appetitive classical conditioning on dopamine efflux in the rat nucleus accumbens shell and core, as dopamine may be differentially activated by conditioned and unconditioned stimuli (CS, US) in these subregions. After implantation of microdialysis cannulae, rats were food restricted and trained for three consecutive days with three acquisition sessions per day. A 10-s noise (CS) was immediately followed by the delivery of two reward pellets (US) for the conditioned group (paired presentation), whereas conditioned stimuli and unconditioned stimuli were presented at random for the control group (unpaired presentation). On the fourth day, all rats were given a further CS + US session and two CS-alone sessions, and extracellular dopamine concentrations were measured (7.5 min/per sample). Behavioural measures (number of nose pokes, latency to nose poke after conditioned stimuli onset, locomotor activity) demonstrated that the paired groups showed a high level of conditioning. CS + US presentation increased dopamine equally in both shell and core of the paired and unpaired groups. CS alone presentation induced a conditioned dopamine release only in the paired groups. No significant difference was found between shell and core. Unlike previous conditioning paradigms involving either a more salient US (foot shock, addictive drug) or a more complex CS, the present paradigm, using normal reward pellets as US and a discrete auditory stimulus as CS, did not lead to differential responses in dopamine efflux in shell and core subregions of the nucleus accumbens.

School expulsion as a process and an event: before and after effects on children at risk for school discipline

A better understanding of expulsion as an act, a process, and an educational intervention leads to an entirely different understanding of student behavior and disciplinary consequences.

NO modulates monocyte chemotactic protein-1 expression in endothelial cells under cyclic strain

Endothelial cells (ECs) under hemodynamic forces increase intracellular reactive oxygen species (ROS) that modulate gene expression. We previously showed that NO attenuated the shear flow-induced gene level. The present study explored the role of endothelial NO in cyclic strain-treated ECs. Treatment of ECs with S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, reduced cyclic strain-induced monocyte chemotactic protein (MCP)-1 expression. Conversely, exposure of ECs to an NO synthase inhibitor augmented MCP-1 mRNA levels. NO attenuated the binding of activator protein-1 to the 12-O-tetradecanoylphobol-13-acetate-responsive element (TRE) in the MCP-1 promoter region. ECs overexpressed with endothelial NO synthase (eNOS) inhibited cyclic strain-induced MCP-1 expression and MCP-1 promoter (-540 bp) activity. Consistently, ECs treated with SNAP or infected with adenovirus carrying eNOS reduced strain-induced superoxide levels. These strain-induced superoxide and MCP-1 expressions were greatly blunted by treating ECs with an NADPH oxidase inhibitor, diphenyleneiodonium chloride or apocynine, but not with a xanthine oxidase inhibitor. ECs infected with adenovirus carrying the dominant-negative mutant of Rac (RacN17), a component of NADPH oxidase, reduced the strain-induced superoxide and MCP-1 expression. In contrast, ECs transfected with a constitutively active Rac (RacV12) increased MCP-1 and 4x TRE promoter activities. However, ECs cotransfected with eNOS and RacV12 reduced those promoter activities. Consistently, the increases of superoxide levels and MCP-1 expression by overexpression of RacV12 were abolished after infecting ECs with eNOS. Our results show that NO from eNOS-inhibiting redox-sensitive MCP-1 expression is mediated via Rac-dependent NADPH oxidase by reducing ROS. This study provides a molecular basis to support the notion that endothelial NO acts as an antioxidant by negatively regulating redox-sensitive gene expression in ECs constantly under hemodynamic influence.

Endothelial exposure to hypoxia induces Egr-1 expression involving PKCalpha-mediated Ras/Raf-1/ERK1/2 pathway

Hypoxia induces endothelial dysfunction that results in a series of cardiovascular injuries. Early growth response-1 (Egr-1) has been indicated as a common theme in vascular injury. Here we demonstrates that in bovine aortic endothelial cells (ECs) subjected to hypoxia (PO(2) approximately 23 mmHg), rapidly increased Egr-1 mRNA expression which peaked within 30 min and decreased afterwards. Treatment of ECs with PD98059, a specific inhibitor to mitogen-activated protein kinase (MAPK/ERK), inhibited this hypoxia-induced Egr-1 expression. The involvement of ERK pathway was further substantiated by the inhibition of Egr-1 promoter activities when ECs were co-transfected with a dominant negative mutant of Ras (RasN17), Raf-1 (Raf 301), or a catalytically inactive mutant of ERK2 (mERK). In addition, the hypoxia-induced transcriptional activity of Elk-1, an ERK substrate, was abolished by administration of PD98059. Addition of calphostin C, a protein kinase C (PKC) inhibitor, completely blocked the hypoxia-augmented Egr-1 expression. The likewise occurred while exposing ECs to D609 to inhibit phospholipase C and BAPTA/AM to chelate intracellular calcium. Hypoxia to ECs increased ERK phosphorylation within 10 min and which was abolished by administration of PD98095, calphostin C, and BAPTA/AM. Hypoxia triggered a transient translocation of PKCalpha from cytosol to membrane fraction concurrent with the association of PKCalpha to Raf-1. Involvement of PKCalpha in mediating ERK activation was further confirmed by the inhibition of ERK and the subsequent Egr-1 gene induction with antisense oligonucleotides to PKCalpha. These results indicate that ECs under hypoxia induce Egr-1 expression and this induction requires calcium, phospholipase C activation, and PKCalpha-mediated Ras/Raf-1/ERK1/2 signaling pathway. Our finding support the importance of specific PKC isozyme linked to MAPK pathway in the regulation of endothelial responses to hypoxia.

Chinese herbal remedy wogonin inhibits monocyte chemotactic protein-1 gene expression in human endothelial cells

Wogonin (Wog), an active component of Scutellaria baicalensis, has antioxidant and anti-inflammatory properties. Monocyte chemotactic protein-1 (MCP-1), a potent chemoattractant for monocytes, plays a crucial role in case of early inflammatory responses, including atherosclerosis. In this study, we investigated the effect of Wog on phorbol ester (PMA)-induced MCP-1 expression in human umbilical vein endothelial cells (ECs). The MCP-1 mRNA levels and MCP-1 release in Wog-treated ECs were measured. Wog inhibited PMA-induced MCP-1 mRNA levels and MCP-1 secretion in a dose-dependent manner. The inhibition of MCP-1 induction by Wog is a transcriptional event, as shown by Wog's significant reduction of both MCP-1 promoter and 4x 12-O-tetradecanoylphorbol-13-acetate response element-luciferase reporter activities. By electrophoretic mobility assay, Wog significantly reduced the AP-1 binding activity induced by PMA. Furthermore, the PMA-induced extracellular signal-regulated kinase 1/2 and c-Jun amino-terminal kinase activities that contributed to AP-1 activity and MCP-1 gene induction were obviously attenuated after pretreating ECs with Wog. The decrease of MCP-1 secretion by Wog pretreatment led to a reduction of monocyte adhesion to ECs. Taken together, our results demonstrate that Wog inhibits MCP-1 induction in ECs; this inhibition is mediated by reducing AP-1 transcriptional activity via the attenuation of ERK1/2 and JNK signal transduction pathways. We conclude that Wog has the potential therapeutic development for use in anti-inflammatory and vascular disorders.

Immediate and long-term outcomes of stent implantation for unprotected left main coronary artery disease

Left main coronary artery (LMCA) disease is now uniformly treated with coronary artery bypass grafting (CABG). However, some patients with LMCA disease do not receive CABG because of high operative risks. The advent of stent implantation has permitted a non-operative improvement in myocardial blood flow in many patients with single- and multi-vessel coronary artery disease. However, the outcomes of stent implantation for unprotected LMCA disease are still unclear. Stent implantation was performed for unprotected LMCA disease in 13 patients; eight patients had high operative risk and five patients had refused CABG. The primary success rate was 100% (13/13 patients). One patient (8%) developed a non-Q-wave myocardial infarction after LMCA stenting. Repeat angiography was obtained in five patients (38%) with recurrent angina, and three patients (23%) received repeated percutaneous transluminal coronary angioplasty (PTCA) for LMCA restenosis. In the follow-up period of 18+/-3 months, 12 patients (92%) remained in satisfactory condition with no further need for surgical intervention. One patient (8%) ultimately required CABG, and she died after CABG at 3 months after LMCA stenting. In conclusion, although CABG remains the standard treatment for LMCA disease, the present study demonstrates that stent implantation is a safe and clinically beneficial revascularization procedure for unprotected LMCA disease in patients who have high operative risk as well as those who refuse CABG.

Sequential activation of protein kinase C (PKC)-alpha and PKC-epsilon contributes to sustained Raf/ERK1/2 activation in endothelial cells under mechanical strain

Endothelial cells (ECs) are constantly subjected to hemodynamic forces including cyclic pressure-induced strain. The role of protein kinase C (PKC) in cyclic strain-treated ECs was studied. PKC activities were induced as cyclic strain was initiated. Cyclic strain to ECs caused activation of PKC-alpha and -epsilon. The translocation of PKC-alpha and -epsilon but not PKC-beta from the cytosolic to membrane fraction was observed. An early transient activation of PKC-alpha versus a late but sustained activation of PKC-epsilon was shown after the onset of cyclic strain. Consistently, a sequential association of PKC-alpha and -epsilon with the signaling molecule Raf-1 was shown. ECs treated with a PKC inhibitor (calphostin C) abolished the cyclic strain-induced Raf-1 activation. ECs under cyclic strain induced a sustained activation of extracellular signal-regulated protein kinases (ERK1/2), which was inhibited by treating ECs with calphostin C. ECs treated with a specific Ca(2+)-dependent PKC inhibitor (Go 6976) showed an inhibition in the early phase of ERK1/2 activation but not in the late and sustained phase. ECs transfected with the antisense to PKC-alpha, the antisense to PKC-epsilon, or the inhibition peptide to PKC-epsilon reduced strain-induced ERK1/2 phosphorylation in a temporal manner. PKC-alpha mediated mainly the early ERK1/2 activation, whereas PKC-epsilon was involved in the sustained ERK1/2 activation. Strained ECs increased transcriptional activity of Elk1 (an ERK1/2 substrate). ECs transfected with the antisense to each PKC isoform reduced Elk1 and monocyte chemotactic protein-1 promotor activity. Our findings conclude that a sequential activation of PKC isoform (alpha and epsilon) contribute to Raf/ERK1/2 activation, and PKC-epsilon appears to play a key role in endothelial adaptation to hemodynamic environment.

Intravenous amiodarone for prevention of atrial fibrillation after coronary artery bypass grafting

BACKGROUND

Atrial fibrillation occurs in 10% to 40% of patients who undergo coronary artery bypass grafting. This prospective study assesses the safety and efficacy of low-dose intravenous amiodarone in the prevention of atrial fibrillation after coronary artery bypass grafting.

METHODS

One hundred forty patients were randomly divided into two groups: an amiodarone group (n = 74) receiving intravenous amiadarone in a loading dose of 150 mg and maintenance dose of 0.4 mg x kg(-1) x h(-1) for 3 days before and 5 days after operation and a control group (n = 76) receiving matching infusions of 5% glucose solution.

RESULTS

Atrial fibrillation occurred in 9 (12%) of the amiodarone group patients and in 26 (34%) of the control group patients during hospitalization (p < 0.01). The maximum ventricular rate during atrial fibrillation was significantly slower in the amiodarone group (107 +/- 21) than in the control group (138 +/- 24 beats per minute, p < 0.01). The duration of atrial fibrillation in the amiodarone group (1.1 +/- 1.2 hours) was significantly shorter than that in the control group (3.2 +/- 1.3 hours, p = 0.01). The two groups had no significant differences in incidence of major morbidity (8 of 74 versus 8 of 76 in amiodarone and control groups, respectively) or mortality (4 of 74 versus 5 of 76). However, the control group had significantly longer intensive care unit stays (132 +/- 24 versus 111 +/- 19 hours, p < 0.01).

CONCLUSIONS

Perioperative low-dose intravenous amiodarone significantly reduces the incidence, ventricular rate, and duration of atrial fibrillation after coronary artery bypass grafting. Furthermore, low-dose intravenous amiodarone is well tolerated and does not increase the risk of intraoperative or postoperative complications.

A randomized, prospective comparison of anterior and posterior approaches to atrioventricular junction modification of medically refractory atrial fibrillation

To compare the safety and efficacy of anterior versus posterior approach for atrioventricular (AV) junction modification, 40 patients with medically refractory paroxysmal (PAF) or chronic atrial fibrillation (AF) were randomly assigned to receive AV junction modification with an anterior or posterior approach. If the ablation session had taken more than 1 hour without success, the alternative ablation approach was attempted. Among the 18 patients assigned to receive the anterior approach, 14 (78%) had a primary success. One (5%) patient had complete AV block after ablation. Three patients crossed over to the posterior approach and had a successful outcome. Fourteen (64%) of 22 patients initially treated with the posterior approach had primary success. One (4%) patient developed complete AV block. Seven patients crossed over to the anterior approach and had a successful outcome. The primary success rate (14/18 vs 14/22, P = NS), incidence of transient AV block (3/18 vs 3/22, P = NS), and complete AV block (1/18 vs 1/22, P = NS) were similar between the anterior approach and posterior approach. The major differences between the two groups showed more radiofrequency pulses (10 +/- 4 vs 6 +/- 3 pulses, P < 0.01), longer procedure duration (50 +/- 24 vs 28 +/- 18 minutes, P < 0.01), and longer fluoroscopy exposure time (28 +/- 17 vs 16 +/- 8 minutes, P < 0.01) in the patients who had primary success with the posterior approach. In conclusion, this study demonstrated that (1) the two techniques had similar efficacies; (2) if one approach was ineffective, switching to the other approach might be safe; (3) combining these two approaches resulted in overall improvement in the success rate of this procedure, and (4) the posterior approach needed more radiofrequency pulses, longer procedural time, and longer fluoroscopy exposure time.

Effect of verapamil on long-term tachycardia-induced atrial electrical remodeling

BACKGROUND

The effect of verapamil on long-term tachycardia-induced atrial electrical remodeling has not been reported.

METHODS AND RESULTS

Forty-eight dogs were randomly divided into verapamil and control groups. The dogs in the verapamil group received verapamil 120 mg every day, those in the control group did not receive verapamil. Atrial effective refractory period (AERP), inducibility of atrial fibrillation (AF), and duration of AF were assessed before and after complete atrioventricular junction ablation with 1-day, 1-week, or 6-week rapid atrial pacing (780 bpm). AERP shortening, AERP dispersion, AERP maladaptation, and inducibility of AF after 1-day pacing was significantly attenuated by verapamil. However, verapamil did not have any significant effect on these parameters in the dogs with 1-week or 6-week pacing. Verapamil did not have any significant effect on the conduction velocity in the dogs with 1-day, 1-week, or 6-week pacing. Before rapid atrial pacing, verapamil significantly prolonged the duration of AF. In the dogs with 1-day pacing, the duration of AF measured immediately after termination of pacing was similar between the control and verapamil groups. However, in the dogs with 1-week or 6-week pacing, the duration of AF after pacing was significantly longer in the verapamil group.

CONCLUSIONS

Verapamil cannot prevent long-term (1 and 6 weeks, respectively) tachycardia-induced changes of atrial electrophysiological properties. Furthermore, verapamil increases the duration of AF in the dogs either before or after long-term rapid atrial pacing.

Cyclic strain induces redox changes in endothelial cells

Our previous studies have shown that cyclic strain to endothelial cells (ECs) increases reactive oxygen species (ROS) that act as second messengers. The potential impact of these enhanced ROS levels on ECs was examined by studying the antioxidant activities and heme oxygenase-1 (HO-1) expression in strained ECs. Cyclic strain to ECs increased lipid peroxidation and augmented oxidation of low-density lipoproteins. ECs subjected to strain increased their superoxide dismutase activities. Concomitantly, glutathione peroxidase activities increased in 3 to 6 hr and returned to basal level 24 hr after continuous cyclic strain treatment. A decrease of glutathione (GSH) was accompanied with an increase of oxidized glutathione (GSSH) level in ECs 3 to 6 hr after strain treatment. This was followed with a return of both GSH and GSSH to basal levels in 24 hr. Consistently, H2O2 treatment of ECs decreased the GSH/GSSG ratio. ECs pretreated with catalase abolished the strain-induced change in GSH/GSSG. Strain treatment, similar to H2O2 exposure, induced HO-1 expression in a time-dependent manner. This induction was inhibited after treating ECs with catalase or free radical scavenger. ECs treated with N-acetyl-cysteine abolished HO-1 gene induction. Our results suggest that cyclic strain-induced ROS cause a transient increase of glutathione peroxidase activity that results in a decrease of GSH level in ECs and that this decrease is crucial to HO-1 induction.

Change of atrial refractory period after short duration of rapid atrial pacing: regional differences and possible mechanisms

It is unknown whether there are regional differences in the change of atrial effective refractory period (ERP) after a short duration of rapid atrial pacing. Furthermore, the effects of calcium channel and potassium channel on this phenomenon have not been extensively investigated. In opened-chest dogs, the endocardial monophasic action potential duration at 90% repolarization (APD90) from the right atrial appendage, and ERP from seven atrial sites were measured before and after rapid atrial pacing at 800 beats/min for 30 minutes. Both atrial ERP and APD90 significantly shortened after rapid atrial pacing. The postpacing atrial ERP and APD90 shortening persisted for 119 +/- 3 and 123 +/- 4 seconds after cessation of pacing, respectively. There was no significant difference in the magnitude or recovery course of atrial ERP shortening after pacing among the seven atrial sites. Pretreatment with nicorandil and d-sotalol had no effects on the magnitude or recovery course of atrial ERP shortening after pacing. However, the degree of ERP and APD90 shortening after pacing was significantly attenuated in the verapamil and ryanodine groups; furthermore, the recovery of ERP and APD90 after cessation of pacing was faster in the two groups. In conclusion, shortening of atrial ERP induced by short-duration rapid atrial pacing was uniform in both atria. Both the adenosine triphosphatase (ATP) dependent potassium current and rapid component of the delayed rectifier did not significantly influence this phenomenon, but both the verapamil and ryanodine could significantly attenuate the degree of atrial ERP and APD90 shortening.

Modulation of Ras/Raf/extracellular signal-regulated kinase pathway by reactive oxygen species is involved in cyclic strain-induced early growth response-1 gene expression in endothelial cells

Endothelial cells (ECs) exposed to cyclic strain induce gene expression. To elucidate the signaling mechanisms involved, we studied the effects of cyclic strain on ECs by using early growth response-1 (Egr-1) as a target gene. Cyclic strain induced a transient increase of Egr-1 mRNA levels that resulted in an increase of binding of nuclear proteins to the Egr-1 binding sequences in the platelet-derived growth factor-A promoter region. ECs subjected to strain enhanced Egr-1 transcription as revealed by promoter activities. Catalase pretreatment inhibited this induction. ECs, transfected with a dominant positive mutant of Ras (RasL61), increased Egr-1 promoter activities. In contrast, transfection with a dominant negative mutant of Ras (RasN17) attenuated this strain inducibility. ECs transfected with a dominant negative mutant of Raf-1 (Raf301) or the catalytically inactive mutant of extracellular signal-regulated kinase (ERK)-2 (mERK2) diminished strain-induced promoter activities. However, little effect on strain inducibility was observed in ECs transfected with a dominant negative mutant of Rac (RacN17) or a catalytically inactive mutant of JNK (JNK[K-R]). Consistently, strain-induced Egr-1 expression was inhibited after ECs were treated with a specific inhibitor (PD98059) to mitogen-activated protein kinase kinase. Moreover, strain to ECs induced mitogen-activated protein kinase/ERK activity. The activation of the ERK pathway was further substantiated by an increase of strain-induced transcriptional activity of Elk1, an ERK substrate. This strain-induced ERK activity was attenuated after ECs were treated with N-acetylcysteine or catalase. Consequently, this Egr-1 gene induction was abolished after ECs were treated with N-acetylcysteine or catalase. Deletion analyses of the promoter region (-698 bp) indicated that cyclic strain and H2O2 shared a common serum response element. Our data clearly indicate that cyclic strain-induced Egr-1 expression is mediated mainly via the Ras/Raf-1/ERK pathway and that strain-induced reactive oxygen species can modulate Egr-1 expression at least partially via this signaling pathway.

The role of P wave in prediction of atrial fibrillation after coronary artery surgery

Atrial fibrillation (AF) is a common arrhythmia after coronary artery bypass surgery (CABG). The purpose of this study was to determine the role of P wave duration, amplitude and dispersion in the prediction of AF after CABG. This study included 120 patients undergoing elective CABG. Clinical characteristics, 12-lead electrocardiogram (ECG), echocardiogram and coronary angiogram were obtained in all patients. We measured P wave duration, amplitude and dispersion from 12-lead ECG in each patient. After CABG, all patients were continuously monitored for AF attacks in the intensive care unit and ordinary ward. Our results showed that age greater than 60 years was the strongest predictor of postoperative AF (p<0.01), with a 3.7-fold greater likelihood of developing postoperative AF compared to ages less than 60 years. Gender was another independent predictor of postoperative AF, with men being 3.0 times more likely to develop postoperative AF compared to women (p = 0.03). The presence of prolonged P wave duration (> or =100 ms in lead II) was also an independent predictor (p = 0.04), with 2.9-fold greater risk of developing postoperative AF compared to a P wave duration of less than 100 ms. The P wave dispersion was similar between patients with and without postoperative AF (29+/-15 vs. 33+/-15 mm, p = NS). In conclusion, old age, male gender and prolonged P wave duration were independent predictors of AF after CABG. However, P wave dispersion and amplitude did not provide significant information in the prediction of postoperative AF.

Regional differences in the recovery course of tachycardia-induced changes of atrial electrophysiological properties

BACKGROUND

Regional differences in recovery of tachycardia-induced changes of atrial electrophysiological properties have not been well studied.

METHODS AND RESULTS

In the control group (5 dogs), atrial effective refractory period (AERP) and inducibility of atrial fibrillation (AF) were assessed before and every 4 hours for 48 hours after complete atrioventricular junction (AVJ) ablation with 8-week VVI pacing. In experimental group 1 (15 dogs), AERP and inducibility of AF were assessed before and after complete AVJ ablation with 8-week rapid right atrial (RA) pacing (780 bpm) and VVI pacing. In experimental group 2 (7 dogs), AERP and inducibility of AF were assessed before and after 8-week rapid left atrial (LA) pacing and VVI pacing. AERP and inducibility and duration of AF were obtained from 7 epicardial sites. In the control group, atrial electrophysiological properties obtained immediately and during 48-hour measurements after pacing did not show any change. In the 2 experimental groups, recovery of atrial electrophysiological properties included a progressive recovery of AERP shortening, recovery of AERP maladaptation, and decrease of duration and episodes of reinduced AF. However, recovery of shortening and maladaptation of AERP and inducibility of AF was slower at the LA than at the RA and Bachmann's bundle.

CONCLUSIONS

The LA had a slower recovery of tachycardia-induced changes of atrial electrophysiological properties, and this might play a critical role in initiation of AF.

Circadian variation of paroxysmal supraventricular tachycardia

BACKGROUND

Various clinical manifestations of cardiovascular diseases have a pattern of circadian variation. In this study, we investigated whether the onset and duration of paroxysmal supraventricular tachycardia (PSVT) has a circadian variation.

METHODS AND RESULTS

In our analysis, we included 105 patients with 498 PSVT episodes. In this study, the onset of PSVT did not have a uniform distribution throughout the 24-h period. There were nearly equal peaks in the time periods from 8:00 to 9:00 AM, 12:00 to 1:00 PM, and 5:00 to 6:00 PM, with a trough at night. The duration of PSVT also did not show a uniform distribution throughout the 24-h period; it increased significantly during the daytime, with a peak between 1:00 and 2:00 PM, another peak between 6:00 and 7:00 PM, and a significant reduction at night.

CONCLUSIONS

The onset and duration of PSVT showed a circadian variation. However, the time-oriented antiarrhythmic therapy for preventing PSVT needs further study.

Mutation of a gene encoding a protein with extracellular matrix motifs in Usher syndrome type IIa

Usher syndrome type IIa (OMIM 276901), an autosomal recessive disorder characterized by moderate to severe sensorineural hearing loss and progressive retinitis pigmentosa, maps to the long arm of human chromosome 1q41 between markers AFM268ZD1 and AFM144XF2. Three biologically important mutations in Usher syndrome type IIa patients were identified in a gene (USH2A) isolated from this critical region. The USH2A gene encodes a protein with a predicted size of 171.5 kilodaltons that has laminin epidermal growth factor and fibronectin type III motifs; these motifs are most commonly observed in proteins comprising components of the basal lamina and extracellular matrixes and in cell adhesion molecules.

Cardiac troponin T, creatine kinase, and its isoform release after successful percutaneous transluminal coronary angioplasty with or without stenting

BACKGROUND

Cardiac troponin T is a sensitive and specific marker for the detection of minor myocardial injury. However, it has been rarely used to monitor myocardial injury after coronary stenting. The purpose of the study was to measure troponin T after apparently successful percutaneous transluminal coronary angioplasty (PTCA) with or without coronary stenting and to compare its result with serum creatine kinase and its isoform, CKMB.

METHODS

The incidence of cardiac troponin T elevation was compared with that of creatine kinase or CKMB in 120 consecutive patients with symptomatic ischemia undergoing visually successful PTCA with (n = 59) or without stenting (n = 61). Troponin T, creatine kinase, and CKMB were measured before, immediately after, and 18 to 24 hours after the procedures were performed.

RESULTS

No patient had abnormal troponin T, creatine kinase, or CKMB levels before and immediately after the procedures. Moreover, no patient showed electrocardiographic evidence of myocardial infarction. Troponin T was elevated in 17 patients at 18 to 24 hours after coronary stenting and in eight patients after PTCA. Both creatine kinase and CKMB were elevated in five patients after coronary stenting and in three patients after PTCA. The frequency of abnormal troponin T levels was significantly higher than that of creatine kinase or CKMB after coronary interventions (21% vs 6.7%; p < 0.01), and it was significantly higher after stenting when compared with angioplasty alone (29% vs 13%; p < 0.05). Patients with abnormal troponin T levels were more likely to undergo repeat revascularization than those without (24% vs 6%; p < 0.01).

CONCLUSION

Cardiac troponin T is more sensitive than creatine kinase and CKMB in detecting minor myocardial injury after coronary interventions. The incidence of troponin T release is higher in the patients undergoing stent implantation than in patients treated with angioplasty alone.

Comparisons of quality of life and cardiac performance after complete atrioventricular junction ablation and atrioventricular junction modification in patients with medically refractory atrial fibrillation

OBJECTIVES

This study compared the long-term effects of complete atrioventricular junction (AVJ) ablation with those of AVJ modification in patients with medically refractory atrial fibrillation (AF).

BACKGROUND

Comparisons between the long-term effects of AVJ ablation with those of AVJ modification in patients with medically refractory AF have not been systematically studied.

METHODS

Sixty patients with medically refractory AF were randomly assigned to receive complete AVJ ablation with permanent pacing or AVJ modification. Subjective perception of quality of life (QOL) was assessed by a semiquantitative questionnaire before and 1 and 6 months after ablation. Cardiac performance was evaluated by echocardiography and radionuclide angiography within 24 h (baseline) and at 1 and 6 months after ablation.

RESULTS

Both methods were associated with significant improvement in general QOL and a significant reduction in the frequency of major symptoms and symptoms during attacks. The frequency of hospital admission and emergency room visits and antiarrhythmic drug trials significantly decreased after ablation in both groups. However, patients after complete AVJ ablation had a significantly greater improvement in general QOL and a significantly reduced frequency of major symptoms and symptoms during attacks (including palpitation, dizziness, chest oppression, blurred vision and syncope). Left ventricular (LV) systolic function and the ability to perform activities of daily life significantly improved after ablation in patients with depressed LV function in both groups. All improvements after ablation or modification were maintained over the 6-month follow-up period.

CONCLUSIONS

AVJ ablation with permanent pacing, as compared with AVJ modification, had a significantly greater ability to decrease the frequency of attacks and the extent of symptoms of AF, and the patients who received this procedure were more satisfied with their general well-being.

Transient ST elevation and left ventricular asynergy associated with normal coronary artery and Tc-99m PYP Myocardial Infarct Scan in subarachnoid hemorrhage

A 72-year-old woman who presented with transient electrocardiographic ST segment elevation and left ventricular asynergy in an acute phase of subarachnoid hemorrhage was found to have normal coronary angiogram and normal Tc-99m PYP myocardial infarct scan. These findings suggested that noninvasive Tc-99m PYP myocardial infarct scan could substitute coronary angiogram for differentiating wall motion and electrocardiographic abnormalities secondary to subarachnoid hemorrhage from those caused by coronary artery disease in patients with subarachnoid hemorrhage.

Cyclic strain-induced reactive oxygen species involved in ICAM-1 gene induction in endothelial cells

Vascular endothelial cells (ECs) are constantly subjected to pressure-induced strain. We have previously demonstrated that strain can induce intercellular adhesion molecule-1 (ICAM-1) expression in ECs. The molecular mechanisms of gene induction by strain, however, remain unclear. Recent evidence suggests that intracellular reactive oxygen species (ROS) may act as second messengers. The potential role of ROS in strain-induced ICAM-1 expression was examined. ECs grown on a flexible membrane base were deformed with various sinusoidal negative pressures to produce an average strain of 12%. Cyclic strain induced an increase in intracellular ROS measured by fluorescent intensity of dichlorofluorescein formed after peroxidation. Maximal levels of ROS were seen after 30 minutes. Levels subsequently decreased but remained elevated compared with unstrained groups. Concomitantly, a sustained increase of H2O2 decomposition activity was observed in strained ECs. Both ROS and H2O2 decomposition activity returned to basal levels after removal of the strain. ECs treated with an antioxidant (N-acetylcysteine or catalase) inhibited strain-induced ROS generation and ICAM-1 mRNA levels followed by decreased ICAM-1 expression on EC surfaces. This inhibition may account for the reduced monocytic cell adhesion in antioxidant-treated ECs but not in strained controls. Our findings indicate that cyclic strain-induced monocyte adhesion to ECs is mediated, at least in part, by an increase of ICAM-1 gene expression via the elevation of ROS levels in strained ECs. Our results support the importance of intracellular ROS in the modulation of hemodynamic force-induced endothelial responses.

Atrioventricular node reentrant tachycardia in patients with a prolonged AH interval during sinus rhythm: clinical features, electrophysiologic characteristics and results of radiofrequency ablation

Among a consecutive series of 600 patients who underwent radiofrequency catheter ablation for AV node reentrant tachycardia, 14 patients (age 29-76 years) had a prolonged AH interval during sinus rhythm (172 +/- 18 ms, range 140 to 200). Seven of them had unsuccessful ablation during the previous ablation sessions. Eight patients with anterograde dual AV node pathway physiology received anterograde slow pathway ablation, and the other 6 patients without dual-pathway physiology received retrograde fast pathway ablation. All patients had successful elimination of AV nodal reentrant tachycardia after a mean of 4 +/- 4 radiofrequency applications, power level 36 +/- 6 watts and a pulse duration of 42 +/- 4 seconds. The postablation AH interval remained unchanged. During a follow-up period of 25 +/- 13 months, one patient who received slow pathway ablation developed 2:1 AV block with syncope. As compared with the other 586 patients without a prolonged AH interval, these 14 patients had significantly poorer anterograde AV nodal function and lower incidence of anterograde dual AV node physiology (P < 0.01). We concluded that slow pathway ablation in patients with dual pathway physiology, and retrograde fast pathway ablation in patients without dual pathway physiology were effective and safe in patients with a prolonged AH interval. However, delayed onset of symptomatic AV block is possible and careful follow-up is necessary.

Atrioventricular node reentrant tachycardia in patients with a long fast pathway effective refractory period: clinical features, electrophysiologic characteristics, and results of radiofrequency ablation

Twenty-two patients (group 1) with AV node reentrant tachycardia and a baseline fast pathway effective refractory period (ERP) > or = 500 msec were compared with 30 consecutive patients (group 2) with AV node reentrant tachycardia and a fast pathway ERP < 500 msec. Both groups underwent slow pathway ablation. In the patients with complete elimination of slow pathway, the fast pathway ERP and shortest 1:1 conduction cycle length shortened significantly after ablation but was greater in group 1 (n = 14) than in group 2 (n = 21) (125 +/- 78 msec vs 48 +/- 29 msec, p < 0.001 and 103 +/- 72 msec vs 52 +/- 30 msec, p < 0.001, respectively). In group 1, the shortening of fast pathway ERP was correlated to baseline difference between anterograde fast and anterograde slow ERP (r = 0.806, p < 0.001, slope = 1.08), and the shortening of fast pathway shortest 1:1 conduction cycle length was correlated to baseline difference between anterograde fast and anterograde slow shortest 1:1 conduction cycle length (r = 0.885, p < 0.001, slope = 1.47). During follow-up bradycardia did not develop in any patient and no one required pacing. This shortening of the fast pathway ERP and shortest 1:1 conduction cycle length after complete elimination of slow pathway reduced the concern of subsequent impairment of AV node conduction.

Radiofrequency catheter modification of sinus node for inappropriate sinus tachycardia: a case report

We present here, the case of a 22-year-old male suffering from persistent tachycardia for the past 3 years. His resting pulse rate was rarely below 100 beats/min, and it frequently increased to as high as 150 beats/min even after a minimal of activity. Associated symptoms included palpitation, chest tightness, dyspnea and presyncope, either during rest or with exercise. Propranolol and verapamil could not control the tachycardia. The application of radiofrequency energy to an area in the superior right atrium that demonstrated a discrete electrogram with earliest endocardial activation during tachycardia resulted in a decrease in sinus rate from 120 beats/min to 70 beats/min. Follow-up on Holter monitor, performed one month later, demonstrated an average heart rate of 84 beats/min (range 60-125). In exercise tolerance test, the patient exercised for 9 minutes, achieving a maximum heart rate of 140 beats/min. This patient remained asymptomatic without any antiarrhythmic drug during the 3-month follow-up period. Medical management in case of patients showing disabling inappropriate sinus tachycardia refractory, sinus node modification could be considered as an suitable alternative to complete atrioventricular junctional ablation.

Cyclic strain-induced monocyte chemotactic protein-1 gene expression in endothelial cells involves reactive oxygen species activation of activator protein 1

Endothelial cells (ECs) are constantly exposed to blood pressure-induced mechanical strain. We have previously demonstrated that cyclic strain can induce gene expression of monocyte chemotactic protein-1 (MCP-1). The molecular mechanisms of gene induction by strain, however, remain unclear. Recent evidence indicates that intracellular reactive oxygen species (ROS) can act as a second messenger for signal transduction and thus affect gene expression. The potential role of ROS in strain-induced MCP-1 expression was investigated. ECs under cyclic strain induced a sustained elevated production of intracellular superoxide. ECs under strain or pretreated with either H2O2 or xanthine oxidase/hypoxanthine induced MCP-1 expression. Strain- or oxidant-induced MCP-1 mRNA levels could be inhibited by treating ECs with catalase or antioxidant N-acetyl-cysteine (NAC). Functional analysis of MCP-1 promoter and site-specific mutations indicates that the proximal tissue plasminogen activator-responsive element (TRE) in the -60-bp promoter region is sufficient for strain or H2O2 inducibility. Electrophoretic mobility shift assays demonstrated an increase of nuclear proteins binding to TRE sequences from ECs subsequent to strain or H2O2 treatment. NAC or catalase pretreatment of ECs inhibited the strain- or H2O2-induced AP-1 binding. These results clearly indicate that cyclic strain inducibility of MCP-1 in ECs uses the interaction of AP-1 proteins with TRE sites via the elevation of intracellular ROS levels in strained ECs. These findings emphasize the importance of intracellular ROS in the modulation of hemodynamic force-induced gene expression in vascular ECs.

Electrophysiologic characteristics and radiofrequency catheter ablation in atrioventricular node reentrant tachycardia with second-degree atrioventricular block

INTRODUCTION

Detailed electrophysiologic study of AV nodal reentrant tachycardia (AVNRT) with 2:1 AV block has been limited.

METHODS AND RESULTS

Six hundred nine consecutive patients with AVNRT underwent electrophysiologic study and radiofrequency catheter ablation of the slow pathway. Twenty-six patients with 2:1 AV block during AVNRT were designated as group I, and those without this particular finding were designated as group II. The major findings of the present study were: (1) group I patients had better anterograde and retrograde AV nodal function, shorter tachycardia cycle length (during tachycardia with 1:1 conduction) (307 +/- 30 vs 360 +/- 58 msec, P < 0.001), and higher incidence of transient bundle branch block during tachycardia (18/26 vs 43/609, P < 0.001) than group II patients; (2) 21 (80.8%) group I patients had alternans of AA intervals during AVNRT with 2:1 AV block. Longer AH intervals (264 +/- 26 vs 253 +/- 27 msec, P = 0.031) were associated with the blocked beats. However, similar HA intervals (51 +/- 12 vs 50 +/- 12 msec, P = 0.363) and similar HV intervals (53 +/- 11 vs 52 +/- 12, P = 0.834) were found in the blocked and conducted beats; (3) ventricular extrastimulation before or during the His-bundle refractory period bundle could convert 2:1 AV block to 1:1 AV conduction.

CONCLUSIONS

Fast reentrant circuit, rather than underlying impaired conduction of the distal AV node or infranodal area, might account for second-degree AV block during AVNRT. Slow pathway ablation is safe and effective in patients who have AVNRT with 2:1 AV block.