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The environment noise may disturb animal behavior and echolocation via three potential mechanisms: acoustic masking, reduced attention and noise avoidance. Compared with the mechanisms of reduced attention and noise avoidance, acoustic masking is thought to occur only when the signal and background noise overlap spectrally and temporally. In this study, we investigated the effects of spectrally non-overlapping noise on echolocation pulses and electrophysiological responses of a constant frequency–frequency modulation (CF-FM) bat, Hipposideros pratti. We found that H. pratti called at higher intensities while keeping the CFs of their echolocation pulses consistent. Electrophysiological tests indicated that the noise could decrease auditory sensitivity and sharp intensity tuning, suggesting that spectrally non-overlapping noise imparts an acoustic masking effect. Because anthropogenic noises are usually concentrated at low frequencies and are spectrally non-overlapping with the bat’s echolocation pulses, our results provide further evidence of negative consequences of anthropogenic noise. On this basis, we sound a warning against noise in the foraging habitats of echolocating bats.

Background With the increasing prevalence of metabolic syndrome (MS), there is a need to track and predict the development of MS. In this study, we established a Markov model to explore the natural history and predict the risk of MS. Methods A total of 21,777 Chinese individuals who had at least two consecutive health check-ups between 2010 and 2015 were studied. MS was defined using the Chinese Diabetes Society criteria. Twelve metabolic abnormal states (the no component state, four isolated component states, six 2-component states, and the MS state) were contained in each Markov chain. The transition probability was the mean of five probabilities for the transition between any two states in 2 consecutive years. Results The dyslipidemia or overweight/obesity components were most likely to initiate the progress of MS in individuals aged 18–49. However, for individuals over 50 years old, the most likely initiating component of MS was dyslipidemia or hypertension. People who initially had dyslipidemia were most likely to develop the combined state of dyslipidemia with overweight/obesity before the age of 50, but after 50 years of age, the state of dyslipidemia merged with hypertension was the most common. Subjects (with the exception of males over 50 years of age who initially had an isolated state of hyperglycemia) who initially had an isolated state of overweight/obesity, hypertension, or hyperglycemia were most likely to develop a combination of one of these initial states with dyslipidemia. Males who initially had isolated hyperglycemia tended to develop hypertension after age 50. There was a greater chance for subjects who initially had an isolated hyperglycemia state or 2-component state that contained hyperglycemia to develop MS within 10 years compared to those who initially had other abnormal metabolic states. Conclusions The occurrence of MS primarily began with overweight/obesity or dyslipidemia in people aged 18–49. However, for those over 50 years old, MS primarily initiated under the conditions of dyslipidemia or hypertension. When MS started under the conditions of overweight/obesity, hypertension or hyperglycemia, dyslipidemia tended to occur next. People who initially had isolated hyperglycemia or a 2-component state that contained hyperglycemia had a higher risk of developing MS than those with other initiating states.

Proteasome inhibition can induce abnormal accumulation and phosphorylation of microtubule-associated protein tau. The major function of tau protein is to promote microtubules assembly and stabilization, and abnormal tau protein would disturb its microtubule-binding function. In this study, proteasome inhibitor MG132 was used to treat hippocampal slices to explore the role and mechanism of Akt/glycogen synthase kinase-3β (GSK-3β) in proteasome inhibition-induced tau abnormality. During the culture period, we measure the lactate dehydrogenase (LDH) content to assay the viability of hippocampal slices. Following 2.5 and 5 μM MG132 treatment for 6 h, we detected the expression, phosphorylation modification, and microtubule-binding function of tau protein of slices. We also analyzed the changed activities of glycogen synthase kinase-3β (GSK-3β) and protein kinase B (PKB/Akt) and the level of heat shock protein 90 (Hsp90) in the process. In addition, co-immunoprecipitation was used to investigate the interaction between Akt and Hsp90, Akt and protein phosphatase-2A (PP2A) in the MG132-treated organotypic hippocampal slices. Our results indicated that proteasome inhibition led to degradation obstacles and abnormal phosphorylation of tau protein. The downregulated Akt/GSK-3β signaling pathway might be responsible for the abnormal phosphorylation of tau protein at multiple sites which further reduced the microtubule-binding function of tau protein. Furthermore, proteasome inhibition decreased the binding capacity of Akt-Hsp90 while increased the Akt-PP2A binding ability which mediated Akt inactivity. This current study establishes a hippocampal slice model targeting Akt/GSK-3β signaling pathway to explore the pivotal role of proteasome inhibition in tau pathology.

Ubiquitin C-terminal hydrolase L1 (UCH-L1) is abundantly expressed in the brain and is critical for the normal function of synapses. cAMP response element binding protein (CREB) is a transcription factor which initiates the expression of proteins that related to the regulation of synaptic plasticity and memory function. Studies have shown that UCH-L1 can influence the expression and activity of CREB, but the underlying mechanisms remain unclear. In this study, we used UCH-L1 inhibitor LDN to treat mice hippocampal slices and found that UCH-L1 inhibition caused the dephosphorylation of CREB at Ser133 site. Meanwhile, hyperphosphorylation of microtubule-associated protein tau; increased expression of synaptic protein components of PSD-95 and synapsin-1, and decreased activity of tyrosine kinase Fyn were observed after UCH-L1 inhibition. Moreover, all these alternations have an influence on the normal function of N-methyl-D-aspartate (NMDA) receptor NR2B subunit which is likely to result in the dephosphorylation of CREB. We also found that LDN treatment mediated protein kinase A (PKA) deactivation was involved in the dephosphorylation of CREB. Thus, our study introduces a novel possible mechanism for elaborating the effects of UCH-L1 inhibition on the CREB activity and the implicated signaling pathways.

Background: Increasing serum levels of uric acid (SUA) after menopause in women brought up a hypothesis that estrogenic effect may protectively regulate SUA. Estrogenic effect is a major etiology of uterine fibroids and fibrocystic breast disease. The study aimed to explore SUA among patients suffering from these diseases to enhance the hypothesis. Methods: Overall, 1349 female participants were selected into three cases: Case I having uterine fibroids (n=568), Case II having fibrocycstic breast disease (n=608) and Case III having uterine fibroids combining with fibrocycstic breast disease (n=173); 4206 participants without these diseases were selected as controls. Based on health check-up data from 2011 to 2012, in Dongying Shengli Oilfield Central Hospital, a cross-sectional study was conducted to examine the difference in SUA between the case and control. We adjusted covariates by generalized linear regression mode. Results: From 19 to 44 yr, SUA of Case I to Case III were lower than controls by 8.46 umol/L (P=0.011), 5.88umol/L (P=0.014) and 9.39 umol/L (P=0.059), respectively. From 45–54 yr, no significant differences were between three cases and controls. In Case I and its control: from 54–59 yr, differences were not significant; from 60 to 72 yr, SUA in Case I was lower than the control by 32.02umol/L (P=0.003). Conclusion: Participants of uterine fibroids and fibrocystic breast disease had a lower SUA except the stage of menopause, which indirectly supported that estrogenic effect, may protectively decrease SUA.

To investigate the association between serum direct bilirubin (DBIL) with metabolic syndrome (MS) and its components.A dynamic health check-up cohort study was set up from 2006 to 2011. 5 258 participants who satisfied the two basic rules: 1) being free of MS at the 1(st) health check-up program; 2) having at least two intact health checks were included in this study. With generalized estimating equation (GEE) model, after adjusting for items as age, gender, smoking, drinking, alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase, uric acid, blood urea nitrogen and white blood cells, the multivariable relative risks (RRs) of DBIL with MS and their components were analyzed.The RRs of DBIL for MS was 0.722 (95%CI: 0.654-0.797), which showing a dose-response. Serum DBIL was negatively associated with obesity and hyperlipidemia. Taking factors as gender and age into account, in the45 years and 45-55 years groups, the RRs of DBIL for MS in females appeared as 0.516 (95%CI: 0.349-0.761) and 0.435 (95%CI: 0.256-0.740). And in males of45 years and 45-55 years, the RRs of DBIL for MS were 0.738 (95% CI: 0.644-0.846) and 0.790 (95% CI:0.667-0.937), respectively.The elevated DBIL levels in serum appeared an early biomarker for MS and its components (obesity and hyperlipidemia). In particular,they may play a role in reducing the risk of MS in both females and males before 55 years of age.

Purpose Elevation in serum alanine aminotransferase (ALT) levels is a biomarker for metabolic syndrome (MS); however, the relationship has not been fully investigated within the reference interval of ALT levels. Our objective was to explore the relationship between serum ALT levels within the reference interval and MS in Chinese adults. Materials and methods This cross-sectional study included 16028 adults, who attended routine health check-ups at Shengli Oilfield Central Hospital from January 2006 to March 2012. The reference interval of serum ALT level was defined as less than 40 U/L. Logistic regression models and restricted cubic spline were used to evaluate the association of ALT with MS. Results The prevalence of MS in the total population was 13.7% (6.4% for females and 18.4% for males). Multiple logistic regression showed that ALT levels were positively associated with MS after adjustment for potential confounding factors. The odds ratio of MS in the top quartile was 4.830 [95% confidence interval (CI): 2.980-7.829] in females and 3.168 (95% CI: 2.649-3.790) in males, compared with the ALT levels in the bottom quartile. The restricted cubic spline models revealed a positive non-linear dose-response relationship between ALT levels and the risk of MS in women (p for nonlinearity was 0.0327), but a positive linear dose-response relationship in men (p for nonlinearity was 0.0659). Conclusion Serum ALT levels within the reference interval are positively associated with MS in a dose-response manner. Elevated ALT levels, even within the reference interval, may reflect early dysmetabolic changes.

The neural modulation in central auditory system plays an important role in perception and processing of sound signal and auditory cognition. The inferior colliculus (IC) is both a relay station in central auditory pathway and a sub-cortical auditory center doing the sound signal processing. IC is also modulated by the descending projections from the cortex and auditory thalamus, medial geniculate body, and these neural modulations not only can affect ongoing sound signal processing but can also induce plastic changes in IC.

Background Many MetS related biomarkers had been discovered, which provided the possibility for building the MetS prediction model. In this paper we aimed to develop a novel routine biomarker-based risk prediction model for MetS in urban Han Chinese population. Methods Exploring Factor analysis (EFA) was firstly conducted in MetS positive 13,345 males and 3,212 females respectively for extracting synthetic latent predictors (SLPs) from 11 routine biomarkers. Then, depending on the cohort with 5 years follow-up in 1,565 subjects (male 1,020 and female 545), a Cox model for predicting 5 years MetS was built by using SLPs as predictor; Area under the ROC curves (AUC) with 10 fold cross validation was used to evaluate its power. Absolute risk (AR) and relative absolute risk (RAR) were calculated to develop a risk matrix for visualization of risk assessment. Results Six SLPs were extracted by EFA from 11 routine health check-up biomarkers. Each of them reflected the specific pathogenesis of MetS, with inflammatory factor (IF) contributed by WBC & LC & NGC, erythrocyte parameter factor (EPF) by Hb & HCT, blood pressure factor (BPF) by SBP & DBP, lipid metabolism factor (LMF) by TG & HDL-C, obesity condition factor (OCF) by BMI, and glucose metabolism factor (GMF) by FBG with the total contribution of 81.55% and 79.65% for males and females respectively. The proposed metabolic syndrome synthetic predictor (MSP) based predict model demonstrated good performance for predicting 5 years MetS with the AUC of 0.802 (95% CI 0.776-0.826) in males and 0.902 (95% CI 0.874-0.925) in females respectively, even after 10 fold cross validation, AUC was still enough high with 0.796 (95% CI 0.770-0.821) in males and 0.897 (95% CI 0.868-0.921) in females. More importantly, the MSP based risk matrix with a series of risk warning index provided a feasible and practical tool for visualization of risk assessment in the prediction of MetS. Conclusions MetS could be explained by six SLPs in Chinese urban Han population. The proposed MSP based predict model demonstrated good performance for predicting 5 years MetS, and the MetS-based matrix provided a feasible and practical tool. Electronic supplementary material The online version of this article (doi:10.1186/s12889-015-1424-z) contains supplementary material, which is available to authorized users.

Background Metabolic Syndrome (MS) is increasingly becoming a major worldwide clinical and public health issue. Thus it is extremely important to study the history of MS and search for the most likely component contributing to start the cascade of confusions of MS. Methods A longitudinal cohort was involved which included the data of 7510 individuals who had at least two routine health check-ups in a six-year follow-up. Based on the data, a Markov model with each chain containing seven states (no component state, four isolated states, 2-component state, and MS state) was built. Annual transition probability was the mean of five probabilities for the transition between the given states between each pair of consecutive years. Results The transition probabilities from the no component state to MS were higher in men than that in women in four age groups. In the young people (men

Chinese characters processing is a complex task involving word identification, phonologic assembly, semantic processing, and letter expression, etc. We built a brain functional network of Chinese characters processing (CCPBFN) with voxels in functional magnetic resonance imaging data as nodes, and significant functional connections among voxels as edges. The primary results revealed that the CCPBFN fell into the small-world networks category, which might reflect an optimal organization pattern for information processing. In a further study of the hierarchy, analyses suggested that voxels tended to connect with others in local regions to form highly interconnected cliques, and the hubs with long-distance connections joined the remote cliques into a whole. We proposed that the CCPBFN might be shaped by the complexity and neural dynamics of Chinese characters processing, which might be corresponding to the neural assemblies.

Noise pollution is recognized as a serious human health problem in modern society. The aim of the present study was to explore the effects of moderate-intensity white noise exposure on learning and memory of mice, and the underlying mechanisms. The learning and memory ability of mice were evaluated by water maze and step-down inhibitory avoidance experiments respectively, following 1, 3, and 6 weeks noise exposure (80 dB SPL, 2h/day). To explore potential mechanisms, we determined levels of oxidative stress in the inferior colliculus (IC), auditory cortex (AC), and hippocampus (the structures comprising the critical encephalic region associated with the acoustic lemniscal ascending pathway), the phosphorylation of microtubule-associated protein tau in the hippocampus (important role in learning and memory), and the basic auditory response properties of neurons in the IC. Moderate-intensity noise exposure impaired the learning and memory ability of mice in both water maze and step-down inhibitory avoidance experiments, and the longer the noise exposure time the greater the impairment. At 6 weeks after noise exposure, there was also evidence of oxidative damage in the IC, AC, and hippocampus, hyperphosphorylated tau protein in the hippocampus, and significant changes in the auditory response properties of neurons in the IC. These data results suggest that moderate-intensity noise can progressively impair the learning and memory ability of mice, which may result from peroxidative damage, tau hyperphosphorylation, and auditory coding alteration.

White noise makes peroxidative damage of the brain, dose it have effect on the phosphorylation of tau in hippocampus? We used 66 mice exposed to 80 dB SPL white noise for 3 days, 1 week, and 3 weeks respectively, then detected the changes of Superoxide dismulase (SOD) activity and malondialdehyde (MDA) content in inferior colliculus (IC), auditory cortex (AC), and hippocampus. Meanwhile we detected the levels of phosphorylation of microtubule-associated protein tau in hippocampus after 1 week and 3 weeks noise exposure. We found that compared with the control group, the value of SOD/MDA of the three brain regions especially the hippocampus of the noise group decreased significantly. At the same time the phosphporylation of tau increased obviously. Our results indicated that the moderate white noise exposure can induced peroxidative damage in IC, AC, and hippocampus; and the peroxidative damage may involved in tau hyperphosphorylation of hippocampus through the lemniscal path.

The present study examines duration-sensitive neurons in the inferior colliculus (IC) of the least horseshoe bat, Rhinolophus pusillus, from China. In contrast to other bat species tested for duration selectivity so far, echolocation pulses emitted by horseshoe bats are generally longer and composed of a long constant-frequency (CF) component followed by a short downward frequency-modulated (FM) sweep (CF-FM pulse). We used combined CF-FM pulses to analyze the differential effects that these two pulse components had on the duration tuning in neurons of the horseshoe bat's IC. Consistent with results from other mammals, duration-sensitive neurons found in the least horseshoe bat fall into three main classes: short-pass, band-pass, and long-pass. Using a CF stimulus alone, 54% (51/95) of all IC neurons showed at least one form of duration selectivity at one or more stimulus intensities. In 65 of the 95 IC neurons tested with CF pulses, we were also able to test their duration selectivity for a combined CF-FM pulse, which increased the ratio of duration-sensitive neurons to 66% (43/65). Seven to 15 neurons that failed to show duration tuning for CF bursts became duration sensitive for CF-FM pulses, with most of them exhibiting short-pass (depending on stimulus intensity, between 4 and 8 neurons) or band-pass tuning (1–3 neurons). Increasing stimulus intensities did not affect the duration tuning in 53% (23/43) of duration-sensitive neurons for CF bursts and in about 26% (7/27) for CF-FM stimuli. In the remaining neurons, increasing sound levels generally reduced the ratio of duration-sensitive neurons to 33% for CF and 37% for CF-FM stimulation. In those that remained duration sensitive, louder CF bursts shortened best durations in band-pass neurons and cutoff durations in short- and long-pass neurons, whereas louder CF-FM stimuli reduced the cutoff durations only in short-pass neurons. Bandwidths of band-pass neurons were not significantly affected by any stimulus configuration, with only a slight trend for increasing bandwidths for louder CF bursts (but not CF-FM stimuli). Best durations and cutoff durations reached higher values than those in the other bat species examined so far and roughly match the longer durations of echolocation pulses emitted by horseshoe bats. Therefore presentation of a CF-FM stimulus improved the duration sensitivity in IC neurons by increasing the ratio of duration-tuned neurons and making them less susceptible to changes in signal intensity.

Objectives Highlighted the spectrum of coronary atherosclerosis in asymptomatic population by Computed Tomography Angiography (CTA) and developed a surrogation of expensive CTA to early detect coronary atherosclerosis. Methods Three hundred and seven self-referred urban Han Chinese asymptomatic individuals underwent coronary CTA were consecutively enrolled. Total plaque score (TPS), Segment stenosis score (SSS) and Coronary Artery Disease severity (CADS) were used to measure and illustrate the spectrum of atherosclerosis burden by mapping their incidence and proportion onto coronary artery tree. Logistic regression model was further used to explore the association between lipid biomarkers and TPS (SSS) for developing a surrogation of CTA to early detect coronary atherosclerosis. Results We found that the incidence of TPS, SSS and CADS were up to 71.34%, 68.08%, and 71.34%; and high-risk individuals reached up to 11.07%, 15.31% and 16.29% respectively. All TPS, SSS and CADS were much higher in male than female, and have trend of increasing with age. The most lesion segment emerged on proximal LAD, followed by proximal RCA, mid LAD, proximal LCX, and mid RCA with mixed plaque as dominant. HDL-C was a predictor to both TPS [OR: 0.12 (0.02–0.82)] and SSS [OR: 0.15 (0.03–0.76)], and could identify the serious atherosclerosis subjects of TPS or SSS score >5 (AUC 0.73 and 0.70). Conclusions The atherosclerosis plaque burden was about one in ten as high-risk individuals in this specific urban Han Chinese population. As potential surrogation of CTA, HDL-C was recognized as a significant predictor to atherosclerosis burden and revealed a good performance for identifying high-risk individuals.