Theta-rhythmic drive between medial septum and hippocampus in slow-wave sleep and microarousal: a Granger causality analysis

Medial septum (MS) plays a critical role in controlling the electrical activity of the hippocampus (HIPP). In particular, theta-rhythmic burst firing of MS neurons is thought to drive lasting HIPP theta oscillations in rats during waking motor activity and REM sleep. Less is known about MS-HIPP interactions in nontheta states such as non-REM sleep, in which HIPP theta oscillations are absent but theta-rhythmic burst firing in subsets of MS neurons is preserved. The present study used Granger causality (GC) to examine the interaction patterns between MS and HIPP in slow-wave sleep (SWS, a nontheta state) and during its short interruptions called microarousals (a transient theta state). We found that during SWS, while GC revealed a unidirectional MS→HIPP influence over a wide frequency band (2-12 Hz, maximum: ∼8 Hz), there was no theta peak in the hippocampal power spectra, indicating a lack of theta activity in HIPP. In contrast, during microarousals, theta peaks were seen in both MS and HIPP power spectra and were accompanied by bidirectional GC with MS→HIPP and HIPP→MS theta drives being of equal magnitude. Thus GC in a nontheta state (SWS) vs. a theta state (microarousal) primarily differed in the level of HIPP→MS. The present findings suggest a modification of our understanding of the role of MS as the theta generator in two regards. First, a MS→HIPP theta drive does not necessarily induce theta field oscillations in the hippocampus, as found in SWS. Second, HIPP theta oscillations entail bidirectional theta-rhythmic interactions between MS and HIPP.

Potentiation of tonic GABAergic inhibition by activation of postsynaptic kainate receptors

Presynaptic kainate-type glutamate ionotropic receptors (KARs) that mediate either the depression or the facilitation of GABA release have been intensively studied. Little attention has been given to the modulation of GABAA receptors (GABAARs) by postsynaptic KARs. Recent studies suggest that two GABAAR populations, synaptic (sGABAAR) and extrasynaptic (eGABAAR) GABAARs, mediate phasic and tonic forms of inhibition, respectively. Tonic inhibition plays an important role in the excitability of neuronal circuits and the occurrence of epileptic seizures. For this study, we are the first to report that the activation of postsynaptic KARs by the KAR agonist, Kainic acid (KA, 5 μM), enhanced tonic inhibition by potentiating eGABAARs. KA enhanced THIP-induced eGABAAR currents and prolonged the rise and decay time of muscimol-induced sGABAAR/eGABAAR currents, but also depressed the amplitude of evoked inhibitory postsynaptic currents (IPSCs), unitary IPSCs (uIPSCs), and muscimol-induced sGABAAR/eGABAAR currents. The PKC inhibitor, staurosporine (1 μM), in the patch pipette solution fully blocked the KA-induced potentiation of tonic inhibition, suggesting the involvement of an intracellular PKC pathway. Our study suggests that the activation of postsynaptic KARs potentiates eGABAARs but depresses sGABAARs. By activating postsynaptic KARs, synaptically released glutamate depresses phasic inhibition to facilitate neuronal plasticity, but potentiates tonic inhibition to protect neurons from over-excitation.

First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers

We report the first direct measurement of the overall characteristics of microwave radio emission from extensive air showers. Using a trigger provided by the KASCADE-Grande air shower array, the signals of the microwave antennas of the Cosmic-Ray Observation via Microwave Emission experiment have been read out and searched for signatures of radio emission by high-energy air showers in the GHz frequency range. Microwave signals have been detected for more than 30 showers with energies above 3×10^{16}  eV. The observations presented in this Letter are consistent with a mainly forward-directed and polarized emission process in the GHz frequency range. The measurements show that microwave radiation offers a new means of studying air showers at E≥10^{17}  eV.

Metabolic syndrome and sex-specific socio-economic disparities in childhood and adulthood: the Korea National Health and Nutrition Examination Surveys

AIMS

To examine whether adulthood and/or childhood sex-specific socio-economic disparities are associated with metabolic syndrome and its components in a developed non-Western setting.

METHODS

Based on the Fourth Korea National Health and Nutrition Examination Surveys, 14 888 people aged ≥ 20 years were analysed to evaluate the effect of adult and childhood socio-economic status on metabolic syndrome. Metabolic syndrome was defined according to the National Cholesterol Education Program Adult Treatment Panel III guidelines. Logistic regression analyses were conducted to calculate the odds ratios for metabolic syndrome and each component of metabolic syndrome in later life.

RESULTS

The age-standardized prevalence of metabolic syndrome was 26.6% for men and 21.3% for women. Compared with the highest level of education, men with the lowest education level were significantly less likely to have metabolic syndrome (odds ratio 0.76, 95% CI 0.60-0.96), whereas the opposite association was found in women (odds ratio 3.29, 95% CI 2.45-4.42). Men who were manual labourers and economically inactive had a lower prevalence of metabolic syndrome compared with those with non-manual jobs (odds ratio 0.82, 95% CI 0.69-0.98 and odds ratio 0.79, 95% CI 0.64-0.99, respectively), but the reverse association was observed in women (odds ratio 1.34, 95% CI 1.04-1.73 and odds ratio 1.40, 95% CI 1.09-1.81, respectively). A significant interaction between combined adulthood and childhood socio-economic status on the presence of metabolic syndrome was observed (P < 0.05).

CONCLUSIONS

Our findings suggest that sex-specific socio-economic disparities in childhood and adulthood have differential effects on the prevalence of metabolic syndrome and its individual components in Korea.

Effect of dietary patterns on serum C-reactive protein level

BACKGROUND AND AIMS

C-reactive protein (CRP) is a marker of inflammation which has been shown in multiple prospective epidemiological studies to predict the risk of cardiovascular disease and metabolic syndrome. Dietary patterns may influence the risk of diseases through the effects of CRP on inflammation. The aim of this study was to examine the relationship of dietary patterns with CRP in blood, taking into consideration gender and blood pressure.

METHODS AND RESULTS

The present cross-sectional analysis included 7574 participants from a large, population-based study of middle-aged Koreans. Four dietary patterns, including 'fruit', 'vegetable', 'meat' and 'coffee', were derived using factor analysis. Multiple linear regressions were used to evaluate the association between dietary patterns and CRP after adjusting for age, sex, education, waist circumference, smoke status and alcohol consumption. We found that the 'vegetable' pattern was inversely associated with CRP (Ptrend = 0.01). The adjusted mean CRP was 0.04 mg/dl lower (95% CI -0.07, -0.01) for subjects in the highest quartile of the 'vegetable' pattern compared with those in the lowest quartile. This inverse association was more pronounced in men with hypertensive blood; CRP concentrations across increasing quartile categories of the 'vegetable' pattern score were 0.1, 0.14, and 0.15 mg/dl reduction compared to the 1st quartile (the lowest quartile) (Ptrend = 0.04, Plinearity = 0.02).

CONCLUSIONS

The inverse association of the 'vegetable' pattern with CRP was assessed, and the association appeared to be more predominant in men with hypertensive blood pressure.

Work-related Musculoskeletal Disorders in Korea Provoked by Workers' Collective Compensation Claims against Work Intensification

This article presents the process of workers’ problems with work related musculoskeletal disorders (WMSDs), the introduction of risk assessments (RA) for their prevention, and the consequences of this process in Korea. In 1997, economic crisis caused a rapid increase of massive layoffs, worker dispatch system introduction, job insecurity, and use of irregular workers resulting in work intensification. Work intensification increased WMSDs, which created massive workers’ compensation collective claims. Workers argued for the reduction of work intensity. The RAs introduced as a consequence of the workers’ struggle is unique in the world. Whereas these RAs were expected to play a pivotal role in WMSDs prevention, they dis not due to workers’ lack of engagement after the compensation struggle. In fact, changes in the compensation judgment system and criteria have resulted in lower compensation approval rates leading to lower workers’ compensation claims. The Korean experience provides insight into WMSDs causes in a globalized world. In such a the globalized world, work intensification as the result of work flexibility could be an international trend.

Relationship of body composition with bone mineral density in northern Chinese men by body mass index levels

Osteoporosis and obesity are severe public health problems in an aging society, and as we all know, bone mineral density (BMD) is closely related to fat mass (FM) and fat distribution. However, studies have long focused on pre- or post-menopausal women, and its presence in men has been underestimated. To investigate the differential impact of fat on BMD, we characterized body composition of northern Chinese men and examined the relationship with BMD according to body mass index (BMI) levels.

METHODS

A cross-sectional study was conducted on 502 healthy northern Chinese men aged 20-89 screened from the participants in a community-based osteoporosis prevention study conducted by the Research Center of Qianfoshan Hospital of Shandong University from 2009 to 2010. The qualified subjects were stratified according to BMI levels as normal weight (18.5 ≤ BMI < 24 kg/m(2), n = 137), overweight (24 ≤ BMI < 28 kg/m(2), n = 225), and obesity (BMI ≥ 28 kg/m(2), n = 140). Total body, left femur, lumbar spine BMD and lean mass (LM), FM, percent body fat (%BF) were measured by dual-energy X-ray absorptiometry. Pearson correlation and age-adjusted partial correlation analyses between body composition-related parameters and BMD were performed. Multiple regression analysis was performed to examine the relationship of BMD with LM, FM and %BF.

RESULTS

Height and weight had positive associations with BMD at all sites, although age had negative associations. Of all subjects, LM and FM were positively correlated with BMD at almost sites (P < 0.01). However, when the subjects were divided into normal weight, overweight and obesity, no relations were reflected between FM and BMD. %BF showed negative correlations with BMD at arm and leg (P < 0.01) in overweight, and with BMD at total body, arm, leg, hip (P < 0.01) in obesity. In regression models, both FM and LM showed statistically positively significant relations with total body and regional BMD in all subjects (all P < 0.05). LM was positively correlated with BMD at almost site (all P < 0.05) in groups, while FM had no association. Interestingly, percent body fat (%BF) had negative associations with BMD at total body, arm, leg and total femur in overweight and obesity.

CONCLUSIONS

The relationship between LM and BMD was certain in northern Chinese men while fat-bone relationship was complicated. %BF had a significantly negative association with total body and regional BMD in overweight and obese men.

FGF receptor genes and breast cancer susceptibility: results from the Breast Cancer Association Consortium

BACKGROUND

Breast cancer is one of the most common malignancies in women. Genome-wide association studies have identified FGFR2 as a breast cancer susceptibility gene. Common variation in other fibroblast growth factor (FGF) receptors might also modify risk. We tested this hypothesis by studying genotyped single-nucleotide polymorphisms (SNPs) and imputed SNPs in FGFR1, FGFR3, FGFR4 and FGFRL1 in the Breast Cancer Association Consortium.

METHODS

Data were combined from 49 studies, including 53 835 cases and 50 156 controls, of which 89 050 (46 450 cases and 42 600 controls) were of European ancestry, 12 893 (6269 cases and 6624 controls) of Asian and 2048 (1116 cases and 932 controls) of African ancestry. Associations with risk of breast cancer, overall and by disease sub-type, were assessed using unconditional logistic regression.

RESULTS

Little evidence of association with breast cancer risk was observed for SNPs in the FGF receptor genes. The strongest evidence in European women was for rs743682 in FGFR3; the estimated per-allele odds ratio was 1.05 (95% confidence interval=1.02-1.09, P=0.0020), which is substantially lower than that observed for SNPs in FGFR2.

CONCLUSION

Our results suggest that common variants in the other FGF receptors are not associated with risk of breast cancer to the degree observed for FGFR2.

Reliability of self-administered Work Ability Index questionnaire among Korean workers

Although the Work Ability Index (WAI) has been used in many countries, its reliability is yet to be validated in Korea. In our study, test-retest results of WAI total score, WAI category and seven subscales were compared. The correlation coefficients of WAI total score and subscales 1 and 2 between test and retest were 0.70, 0.80 and 0.63, respectively. The κ values on WAI category, subscales 4, 5, 6 and 7 were 0.52, 0.32, 0.31, 0.48 and 0.85, respectively. The results of our reliability test show that WAI scores of female, younger and private company workers were found to be higher than those of male, older and public company workers, respectively. We conclude that overall test-retest reliability of WAI in Korea is acceptable. Another notable observation from our study is that work ability dimension (subscales 1, 2 and 7) had a higher reliability, whereas health dimension (subscales 3-6) had a lower reliability.

Enhanced gene transfer to pancreatic islets using glucagon-like peptide-1

OBJECTIVE

The efficient transfer of genes into intact islets is difficult since islets exist as clusters of differentiated cells with little replication potential. Cell proliferation in response to growth factors is known to be accompanied by loosening of cell-to-cell contacts and increasing paracellular permeability. In this study, we investigated whether gene delivery into intact islet cells was facilitated by modulating β-cell proliferation.

METHODS

Isolated rat islets were pretreated with glucagon-like peptide (GLP)-1 or human growth hormone for 24 hours, or with 300 mg/dL of glucose for 48 hours before transduction with a suboptimal dose of recombinant adenoviral vector expressing green fluorescent protein (GFP) and β-galactosidase (multiplicity of infection of 25). Transduction efficiency was assessed by measuring β-galactosidase activity and GFP expression using enzyme-linked immunosorbent assay, flow cytometry, and fluorescence microscopy. The numbers of 7-aminoactinomycin D-positive dead cells and 5-ethynyl-2-deoxyuridine (EdU)-positive proliferating cells were also monitored using flow cytometry and fluorescence microscopy.

RESULTS

The transduction efficiency of rat islet cells by a suboptimal dose of viral vector was significantly improved by GLP-1 pretreatment, accompanied by enhanced cell viability and cell proliferation. An increased GFP expression in islet cells after GLP-1 pretreatment was observed among the increased numbers of EdU-positive proliferating cells.

CONCLUSION

Pretreatment of rat islets with GLP-1 enhanced the transduction efficiency of an adenoviral vector, reducing viral dose burden while improving islet cell viability. From a therapeutic standpoint, genetic modification of pancreatic islets combined with GLP-1 pretreatment may be a promising option for ex vivo gene therapy prior to islet transplantation.

Systematic Review of the Effects of Asbestos Exposure on the Risk of Cancer between Children and Adults

Children are considerably more susceptible to enviro006Emental hazards than adults. This study was conducted to investigate whether the first asbestos exposure in childhood increases the risk of asbestos-related cancer including mesothelioma and lung cancer. MEDLINE (PubMed), Embase, and Google Scholar were searched to find relevant studies published up to July 2012. Six studies reported the relationship between age, including age during childhood, at the first asbestos exposure and mesothelioma. Among them, 4 indicated that people exposed to asbestos in childhood have a higher risk of mesothelioma than those exposed in adulthood. Meanwhile, the other 2 studies showed that asbestos exposure later in life increases the risk of mesothelioma. The results of the 2 studies including non-occupational early childhood exposure report conflicting results. There were 3 studies regarding the relationship between age at first asbestos exposure and lung cancer. However, none of them reported an association between age at first asbestos exposure and the risk of lung cancer. All studies have limitations including small numbers of subjects, the validity of the standardized mortality ratio, and different age categories at first asbestos exposure. There are only a few studies on the harmful effects of asbestos in children in the literature. Therefore, the effect of asbestos exposure during childhood remains unclear and requires further study.

Genetic variants of AICDA/CASP14 associated with childhood brain tumor

We conducted a hospital-based case-control study in Korea to investigate whether apoptosis- and cell cycle control-related genes are associated with childhood brain tumor. Incident brain tumor cases (N = 70) and non-cancer controls (N = 140), frequency-matched by age and gender, were selected from 3 teaching hospitals in Seoul between 2003 and 2006. Tag single nucleotide polymorphisms (SNPs) (N = 297) in 30 genes related to apoptosis and cell cycle control were selected using a pairwise linkage-disequilibrium-based algorithm. Five tag SNPs in 2 genes (AICDA and CASP14) remained significant after adjusted multiple tests. The most significant association with childhood brain tumor risk was for IVS1-401G>C in the AICDA gene [odds ratio (OR) = 2.8; 95% confidence interval (95%CI) = 1.25-6.46]; the polymorphism *9276A>C of CASP14 was associated with decreased brain tumor risk (OR = 0.4; 95%CI = 0.19-0.95). We concluded that genetic polymorphisms in AICDA and CASP14 are associated with risk for brain tumor in Korean children.

Generation of polarization-entangled photon pairs in a Bragg reflection waveguide

We demonstrate experimentally that spontaneous parametric down-conversion in an AlxGa(1-x)As semiconductor Bragg reflection waveguide can make for paired photons highly entangled in the polarization degree of freedom at the telecommunication wavelength of 1550 nm. The pairs of photons show visibility higher than 90% in several polarization bases and violate a Clauser-Horne-Shimony-Holt Bell-like inequality by more than 3 standard deviations. This represents a significant step toward the realization of efficient and versatile self pumped sources of entangled photon pairs on-chip.

A salicylic acid-induced rice (Oryza sativa L.) transcription factor OsWRKY77 is involved in disease resistance of Arabidopsis thaliana

Plant WRKY transcription factors act as either positive or negative regulators of plant basal disease resistance. To comprehensively characterise the complicated functional network, we isolated OsWRKY77 from rice seedlings treated with salicylic acid. OsWRKY77 is a typical WRKY transcription factor, based on in its protein structure analysis, nuclear localisation of the fused OsWRKY77-GFP protein and gel electrophoretic mobility shift assay binding, which demonstrated that OsWRKY77 was able to bind a W-box. Transgenic Arabidopsis lines overexpressing OsWRKY77 repressed growth of Pseudomonas syringae pv. tomato DC3000 (PstDC300), and the reduced susceptibility was associated with enhanced expression of defence-related PR1, PR2 and PR5 genes. These results show that OsWRKY77 is a positive regulator of PR gene expression and basal resistance to the bacterial pathogen PstDC3000.

Mobile phone use, blood lead levels, and attention deficit hyperactivity symptoms in children: a longitudinal study

BACKGROUND

Concerns have developed for the possible negative health effects of radiofrequency electromagnetic field (RF-EMF) exposure to children's brains. The purpose of this longitudinal study was to investigate the association between mobile phone use and symptoms of Attention Deficit Hyperactivity Disorder (ADHD) considering the modifying effect of lead exposure.

METHODS

A total of 2,422 children at 27 elementary schools in 10 Korean cities were examined and followed up 2 years later. Parents or guardians were administered a questionnaire including the Korean version of the ADHD rating scale and questions about mobile phone use, as well as socio-demographic factors. The ADHD symptom risk for mobile phone use was estimated at two time points using logistic regression and combined over 2 years using the generalized estimating equation model with repeatedly measured variables of mobile phone use, blood lead, and ADHD symptoms, adjusted for covariates.

RESULTS

The ADHD symptom risk associated with mobile phone use for voice calls but the association was limited to children exposed to relatively high lead.

CONCLUSIONS

The results suggest that simultaneous exposure to lead and RF from mobile phone use was associated with increased ADHD symptom risk, although possible reverse causality could not be ruled out.