What drives the adoption of online health communities? An empirical study from patient-centric perspective.

BACKGROUND: Online health communities (OHCs) provide platforms for patients to seek advice from physicians and receive professional suggestions online. It can improve the efficiency of patients' diagnosis of simple diseases and alleviate hospital congestion. However, few empirical studies have comprehensively explored the factors influencing patients' intention to use OHCs through objective data. This study aims to fill this gap by identifying key factors that influence patients' acceptance of OHCs and proposing effective ways to promote the applications of OHCs in China. METHODS: Based on the Unified Theory of Acceptance and Usage of Technology (UTAUT), extended with additional constructs identified with patients' information demands in OHCs, this study developed a research model and proposed nine hypotheses. An online survey involving 783 valid responses was conducted in China to collect data to validate the proposed model. Confirmatory factor analysis and partial least squares (PLS) path model were conducted for instrument validation and hypothesis testing. RESULTS: Price value, eHealth literacy, and performance expectancy are the most prominent constructs in the study context. Interestingly, relation quality was also found to have a significant positive relationship with behavioral intention. CONCLUSIONS: Based on these findings, OHC operators need to create a user-friendly platform, improve information quality, set reasonable prices, and establish consummate security systems. Physicians and related organizations can raise awareness and assist patients in developing the skills to appropriately comprehend and utilize information in OHCs. This study contributes to both technology adoption theory and practice.

The Effects of Patient Health Information Seeking in Online Health Communities on Patient Compliance in China: Social Perspective.

BACKGROUND: Online health communities (OHCs) can alleviate the uneven distribution and use of medical resources and severe hospital congestion. Patients may seek health information through OHCs before or after visiting physicians, which may affect their cognition, health literacy, decision-making preferences, and health-related behaviors such as compliance. Social factors (social support, social presence, and responsiveness) are closely related to patients' health information-seeking behavior and are significantly considered in OHCs. OBJECTIVE: This study aimed to explore the effects of patients' health information-seeking behavior (way and effectiveness) on compliance with physicians from the perspectives of patients' perceived social support, social presence, and responsiveness. METHODS: This study established a research model from the perspective of social information processing by using the social exchange theory. An anonymous questionnaire survey was conducted with several Chinese OHCs to collect data. Partial least squares and structural equation modeling were adopted to test the hypotheses and develop the model. RESULTS: This study received 403 responses, of which 332 were valid, giving a validity rate of 82.4% (332/403). Among the sample, 78.6% (261/332) of the individuals were aged between 20 and 40 years, 59.3% (197/332) were woman, 69.9% (232/332) lived in urban areas, and 50% (166/332) had at least a bachelor's degree. The reliability, convergent validity, and discriminant validity were acceptable. Both the way and effectiveness of patients seeking health information through OHCs have a positive impact on their compliance through the mediation of their perceived social support, social presence, and responsiveness from OHCs and other users, and patient compliance can be improved by guiding patient health information-seeking behavior in OHCs from a social perspective. CONCLUSIONS: This study proposes a research model to corroborate that patient health information-seeking behavior (way and effectiveness) in OHCs exerts positive effects on patient compliance with the treatment and physician's advice and provides suggestions for patients, physicians, and OHC service providers in China to help guide patients' health-related behaviors through OHCs to improve patient compliance, patient satisfaction, treatment efficiency, and health outcomes.

Contamination Status of Pet Cats in Thailand with Organohalogen Compounds (OHCs) and Their Hydroxylated and Methoxylated Derivatives and Estimation of Sources of Exposure to These Contaminants.

In this study, we analyzed serum samples of pet cats from Thailand and estimated the contribution to organohalogen compounds (OHCs) exposure through cat food and house dust intake. BDE-209 was predominant in cat sera and accounted for 76% of all polybrominated diphenyl ethers (PBDEs). Decabromodiphenyl ether (BDE-209) is a major contaminant in dry cat food and house dust, which has been estimated to be a source of exposure for Thai pet cats. BDE-209 is a major contaminant of OHCs in dry cat food and house dust, which was estimated to be a source of exposure for Thai pet cats. On the other hand, the level of contamination by PCBs was lower than in other countries. Analysis of pet foods suggested that BDE-209 in pet cat serum was attributable to the consumption of dry cat food. On the other hand, house dust also contained high concentrations of BDE-209. Thus, high levels of BDE-209 in pet cat sera can be attributed to the consumption of dry cat food and house dust. These results suggest that pet cats are routinely exposed to non-negligible levels of OHCs.

Inhibiting DNA methylation alleviates cisplatin-induced hearing loss by decreasing oxidative stress-induced mitochondria-dependent apoptosis via the LRP1-PI3K/AKT pathway.

Cisplatin-related ototoxicity is a critical side effect of chemotherapy and can lead to irreversible hearing loss. This study aimed to assess the potential effect of the DNA methyltransferase (DNMT) inhibitor RG108 on cisplatin-induced ototoxicity. Immunohistochemistry, apoptosis assay, and auditory brainstem response (ABR) were employed to determine the impacts of RG108 on cisplatin-induced injury in murine hair cells (HCs) and spiral ganglion neurons (SGNs). Rhodamine 123 and TMRM were utilized for mitochondrial membrane potential (MMP) assessment. Reactive oxygen species (ROS) amounts were evaluated by Cellrox green and Mitosox-red probes. Mitochondrial respiratory function evaluation was performed by determining oxygen consumption rates (OCRs). The results showed that RG108 can markedly reduce cisplatin induced damage in HCs and SGNs, and alleviate apoptotic rate by protecting mitochondrial function through preventing ROS accumulation. Furthermore, RG108 upregulated BCL-2 and downregulated APAF1, BAX, and BAD in HEI-OC1 cells, and triggered the PI3K/AKT pathway. Decreased expression of low-density lipoprotein receptor-related protein 1 (LRP1) and high methylation of the LRP1 promoter were observed after cisplatin treatment. RG108 treatment can increase LRP1 expression and decrease LRP1 promoter methylation. In conclusion, RG108 might represent a new potential agent for preventing hearing loss induced by cisplatin via activating the LRP1-PI3K/AKT pathway.

Organochlorine pesticides and NDL-PCBs in wild boars from flatland region with intensive agricultural activities.

The objective of this study was to analyse the content of OHCs and NDL-PCBs in wild boar population living in densely populated flatland region with intensive agricultural production. A total of 82 liver samples were analysed by GC-MS method, revealing the presence of minimum one residue in the liver of the majority of animals (92.7%). Most commonly detected residues included ∑ HCH (64.6%), ∑endrin (56.1%) and ∑dieldrin (32.3%). Mean concentrations were in the range ∑endrin > ∑dieldrin > ∑HCH > ∑NDL-PCB > ∑DDT > ∑CHL > ∑endosulfan > methoxychlor. The dominant compound within the total content of NDL-PCBs was PCB 153 (76%). The assessment of daily intake and determination of Health Index indicated that in 6.1% of the samples the consumption of one single portion of wild boar liver would be harmful to human health due to the presence of ∑endrin or NDL-PCBs.

Association Between eHealth Literacy in Online Health Communities and Patient Adherence: Cross-sectional Questionnaire Study.

BACKGROUND: eHealth literacy is significantly associated with patients' online information behavior, physician-patient relationship, patient adherence, and health outcomes. As an important product of the internet, online health communities (OHCs) can help redistribute idle medical resources, increase medical resource utilization, and improve patient adherence. However, studies on eHealth literacy in OHCs are limited. Therefore, this study examined patients' eHealth literacy regarding health information-seeking behavior and physician-patient communication in OHCs. OBJECTIVE: This study aimed to investigate the association between eHealth literacy in OHCs and patient adherence by employing social cognitive theory. METHODS: This was an empirical study, in which a research model consisting of 1 independent variable (patients' eHealth literacy), 3 mediators (physician-patient communication in OHCs, patient health information-seeking behavior in OHCs, and patients' perceived quality of health information in OHCs), 1 dependent variable (patient adherence), and 4 control variables (age, gender, living area, and education level) was established to examine the associations. Multi-item scales were used to measure variables. An anonymous online survey involving 560 participants was conducted through Chinese OHCs in July 2018 to collect data. Partial least squares and structural equation modeling were adopted to analyze data and test hypotheses. RESULTS: The survey response rate was 79.6% (446/560). The reliability, convergent validity, and discriminant validity were acceptable. Age, gender, living area, and education level were positively associated with patient adherence, and gender was positively associated with physician-patient communication and patients' perceived quality of internet health information in OHCs. Patients' eHealth literacy was positively associated with patient adherence through the mediations of physician-patient communication, internet health information-seeking behavior, and perceived quality of internet health information in OHCs. CONCLUSIONS: Results indicate that physician-patient communication, internet health information-seeking behavior, and the perceived quality of internet health information are significantly associated with improving patient adherence via a guiding of eHealth literacy in OHCs. These findings suggest that physicians can understand and guide their patients' eHealth literacy to improve treatment efficiency; OHCs' operators should this strengthen the management of information quality, develop user-friendly features, and minimize the gap between the actual and perceived information quality.

Impact of patient information behaviours in online health communities on patient compliance and the mediating role of patients' perceived empathy.

OBJECTIVE: Patient health information seeking and physician-patient communication in OHCs proved to have impacts on patient compliance, but related studies from psychological perspectives are limited. This study aims to investigate the impact of patient health information seeking and physician-patient communication in OHCs on patient compliance. METHODS: This study established a research model and proposed six hypotheses. An anonymous investigation was conducted using Chinese OHCs. Confirmatory factor analysis, partial least squares, and structural equation modelling were used to test the hypotheses. RESULTS: We received 371 responses, and 316 of them were valid. Patient health information seeking and physician-patient communication frequency in OHCs had positive impacts on patients' perceived affective and cognitive empathies, which positively impacted patient compliance. CONCLUSIONS: Patient compliance can be improved by patient health information seeking and physician-patient communication in OHCs and affective and cognitive empathies. Patients' perceived affective empathy is the preferred perspective to improve patient compliance. PRACTICE IMPLICATIONS: Physicians should encourage patients to seek health information and communicate with them through OHCs, be concerned about patients' experiences, feelings, and attitudes, understand patients' demands and mental states, and show their patients that they can feel patients' pain. Increasing physician-patient communication frequency in OHCs can help improve patient compliance.

Effect of laying sequence and selection of maternal tissues in assessment of maternal transfer of organohalogenated contaminants during chicken egg formation: A pilot study.

Many studies have reported maternal transfer of organic contaminants in oviparous species, with inconsonant results. Egg-laying sequence and selected maternal tissues may impact on assessment of potential maternal transfer of contaminants. Here, this hypothesis was verified by exposing chickens (Gallus domesticus) to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and dechlorane plus (DPs). Concentrations in eggs laid during exposure exhibited periodic fluctuations (conforming to egg-laying cycles) and a decreasing trend during depuration. Fluctuation patterns of DPs and BDE209 differed from those of other compounds. The PBDE congener profiles in eggs were dominated by BDE209 during exposure and by BDE100 and 153 during depuration. The abundance of PCB congener (CB138) which is recalcitrant to metabolism increased with laying sequence. Maternal transfer potential was negatively correlated (P = 0.0014, R2 = 0.7874) to the log KOW of chemicals (log KOW >7) when the muscle, heart, lung, or stomach was used. No correlations were found when the liver, fat, kidneys, or intestine was used (log KOW >7), although DPs and BDE209 showed the highest maternal transfer potential. Different fluctuation patterns of DPs and BDE209 in eggs and increased abundance of BDE209 in eggs laid in the initial egg-laying period imply that the liver, fat, kidney, or intestinal tissues could be more appropriate in assessing maternal transfer of the target analytes.

Age-related changes in the biophysical and morphological characteristics of mouse cochlear outer hair cells.

KEY POINTS: Age-related hearing loss (ARHL) is a very heterogeneous disease, resulting from cellular senescence, genetic predisposition and environmental factors (e.g. noise exposure). Currently, we know very little about age-related changes occurring in the auditory sensory cells, including those associated with the outer hair cells (OHCs). Using different mouse strains, we show that OHCs undergo several morphological and biophysical changes in the ageing cochlea. Ageing OHCs also exhibited the progressive loss of afferent and efferent synapses. We also provide evidence that the size of the mechanoelectrical transducer current is reduced in ageing OHCs, highlighting its possible contribution in cochlear ageing. ABSTRACT: Outer hair cells (OHCs) are electromotile sensory receptors that provide sound amplification within the mammalian cochlea. Although OHCs appear susceptible to ageing, the progression of the pathophysiological changes in these cells is still poorly understood. By using mouse strains with a different progression of hearing loss (C57BL/6J, C57BL/6NTac, C57BL/6NTacCdh23+ , C3H/HeJ), we have identified morphological, physiological and molecular changes in ageing OHCs (9-12 kHz cochlear region). We show that by 6 months of age, OHCs from all strains underwent a reduction in surface area, which was not a sign of degeneration. Although the ageing OHCs retained a normal basolateral membrane protein profile, they showed a reduction in the size of the K+ current and non-linear capacitance, a readout of prestin-dependent electromotility. Despite these changes, OHCs have a normal Vm and retain the ability to amplify sound, as distortion product otoacoustic emission thresholds were not affected in aged, good-hearing mice (C3H/HeJ, C57BL/6NTacCdh23+ ). The loss of afferent synapses was present in all strains at 15 months. The number of efferent synapses per OHCs, defined as postsynaptic SK2 puncta, was reduced in aged OHCs of all strains apart from C3H mice. Several of the identified changes occurred in aged OHCs from all mouse strains, thus representing a general trait in the pathophysiological progression of age-related hearing loss, possibly aimed at preserving functionality. We have also shown that the mechanoelectrical transduction (MET) current from OHCs of mice harbouring the Cdh23ahl allele is reduced with age, highlighting the possibility that changes in the MET apparatus could play a role in cochlear ageing.

An Empirical Study on Patients' Acceptance of Physician-Patient Interaction in Online Health Communities.

In China, the utilization of medical resources is contentious, and a large of hospitals are seriously congested because of the huge population and uneven distribution of medical resources. Online health communities (OHCs) provide patients with platforms to interact with physicians and to get professional suggestions and emotional support. This study adopted the unified theory of acceptance and use of technology to identify factors influencing patients' behavioral intention and usage behavior when interacting with physicians in OHCs. An investigation involving 378 valid responses was conducted through several Chinese OHCs to collect data. Confirmatory factor analysis and structural equation modelling were utilized to test hypotheses. Both the reliability and validity of the scales were acceptable. All five hypotheses were supported, and behavioral intention played a significant mediating role between independent variables and dependent variables. This study clarified the mechanism by which performance expectancy, effort expectancy, social influence and attitude toward using technology affect usage behavior through the mediation of behavioral intention in OHCs. These findings suggest that OHCs can change the actions of websites such as adopting some incentives to promote patients' intention of interaction. Physicians should understand patients' actual attitudes toward OHCs and try to guide patients in their interactions, improving the quality of physician-patient interaction.

Exploring the Role of Online Health Community Information in Patients' Decisions to Switch from Online to Offline Medical Services.

BACKGROUND: Online healthcare has become an important part of healthcare services. Patients can access unlimited information reflecting a doctor's service quality in online health communities (OHCs). This information can reduce information asymmetry between patients and doctors, and further promote patient decisions. In this study, we focus on the patient's decision to switch from a doctor's online medical service to the same doctor's offline service. OBJECTIVES: We classify OHC information into objective information and subjective information. Following this, we investigate how these two types of information influence patient decisions to switch from a doctor's online to offline medical service, and explore the nature of interaction between the two types of influence. METHODS: We collected data from a leading OHC in China and constructed a longitudinal dataset to examine our research questions. To control for doctor heterogeneity and common trends across time, we leveraged fixed effects at the doctor level and monthly fixed effects in our models, respectively. RESULTS: Our findings demonstrate a strong relationship between OHC information and patient decisions to switch from a doctor's online to offline medical service. Patients are more likely to switch from online to offline medical services with doctors whose subjective and objective information on their homepages indicate a higher quality (ßSubjective = 0.001, p < 0.001; αObjective = 0.019, p < 0.002). We also observe that patients prefer doctors who do not exhibit objective information that indicates low-quality service over those who show such information on their homepages, even though the chosen doctor provides a lower-quality service (αLow_Objective = -0.032, p < 0.006). Further, we find that the influence of subjective information on patient decisions crowds out the influence of objective information. CONCLUSION: This study investigates the role of subjective and objective information on patient decisions to switch from a doctor's online to offline medical service and the interaction effect between these two types of information. This study provides valuable theoretical and practical implications.

Effects of a complex contaminant mixture on thyroid hormones in breeding hooded seal mothers and their pups.

There is a general lack of information on the possible effects of perfluoroalkyl substances (PFASs) on thyroid hormones (THs) in wildlife species. The effects of PFASs, which are known endocrine disruptors, on the TH homeostasis in hooded seals (Cystophora cristata) have yet to be investigated. Previously, correlations were found between plasma thyroid hormone (TH) concentrations in hooded seals, and organohalogen contaminants (OHCs) and hydroxyl (OH)-metabolites. Because animals are exposed to multiple contaminants simultaneously in nature, the effects of the complex contaminant mixtures that they accumulate should be assessed. Herein, we analyse relationships between plasma concentrations of multiple contaminants including protein-associated PFASs, hydroxylated metabolites of polychlorinated biphenyls (OH-PCBs) and lipid soluble OHCs and plasma concentrations of free and total THs, i.e. triiodothyronine (FT3, TT3) and thyroxine (FT4, TT4) in hooded seal mothers and their pups. The perfluoroalkyl carboxylates (PFCAs) were the most important predictors for FT3 concentrations and TT3:FT3 ratios in the mothers. The FT3 levels decreased with increasing PFCA levels, while the TT3:FT3 ratios increased. In the pups, hexachlorocyclohexanes (HCHs) were the most important predictors for TT3:FT3 ratios, increasing with increasing HCHs levels. Additionally, perfluoroalkyl sulfonates (PFSAs) and PFCAs were important predictors for FT4:FT3 ratios in hooded seal pups, and the ratio increased with increasing concentrations. The study suggests that PFASs contribute to thyroid disruption in hooded seals exposed to complex contaminant mixtures that include chlorinated and fluorinated organic compounds.

Hepatic phase I and II biotransformation responses and contaminant exposure in long-finned pilot whales from the Northeastern Atlantic.

Faroe Island pilot whales have been documented to have high body burdens of organohalogen contaminants (OHCs), including polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs), but low burdens of their respective hydroxylated metabolites (OH-PCBs and OH-PBDEs). The present study investigated the hepatic expression and/or catalytic activities of phase I and II biotransformation enzymes in relation to hepatic concentrations of target OHCs, including OH-PCBs and OH-PBDEs, in long-finned pilot whales (Globicephala melas) from the Northeastern Atlantic. CYP1A, 2B, 2E and 3A protein expressions were identified in juveniles and adult males, but not in adult females. Ethoxyresorufin-O-deethylase (EROD) activity was significantly lower in adult females than in juveniles and adult males. Using multivariate analyses to investigate relationships between biological responses and OHC concentrations, a positive relationship was identified between EROD and OHCs. The activity levels of phase II conjugating enzymes (uridine 5'-diphospho-glucuronosyltransferase [UDPGT], and glutathione S-transferase [GST]) were low. The analyses of mRNA expression did not show correlative relationships with OHC concentrations, but cyp1a and ahr transcripts were positively correlated with EROD activity. We suggest that the low concentrations of OH-PCBs and OH-PBDEs reported in pilot whales is probably due to the identified low phase I biotransformation activities in the species.

Spatial variation in the accumulation of POPs and mercury in bottlenose dolphins of the Lower Florida Keys and the coastal Everglades (South Florida).

The bottlenose dolphin (Tursiops truncatus) is an upper trophic level predator and the most common cetacean species found in nearshore waters of southern Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDXs, HCHs, HCB, Σ PCDD/Fs and Σ DL-PCBs) in blubber samples of bottlenose dolphins from LFK (n = 27) and FCE (n = 24). PCBs were the major class of compounds found in bottlenose dolphin blubber and were higher in individuals from LFK (Σ 6 PCBs LFK males: 13,421 ± 7730 ng g-1 lipids, Σ 6 PCBs LFK females: 9683 ± 19,007 ng g-1 lipids) than from FCE (Σ 6 PCBs FCE males: 5638 ng g-1 ± 3627 lipids, Σ 6 PCBs FCE females: 1427 ± 908 ng g-1 lipids). These levels were lower than previously published data from the southeastern USA. The Σ DL-PCBs were the most prevalent pollutants of dioxin and dioxin like compounds (Σ DL-PCBs LFK: 739 ng g-1 lipids, Σ DL-PCBs FCE: 183 ng g-1 lipids) since PCDD/F concentrations were low for both locations (mean 0.1 ng g-1 lipids for LFK and FCE dolphins). The toxicity equivalences of PCDD/Fs and DL-PCBs expressed as TEQ in LFK and FCE dolphins is mainly expressed by DL-PCBs (81% LFK - 65% FCE). T-Hg concentrations in skin were significantly higher in FCE (FCE median 9314 ng g-1 dw) compared to LFK dolphins (LFK median 2941 ng g-1 dw). These concentrations are the highest recorded in bottlenose dolphins in the southeastern USA, and may be explained, at least partially, by the biogeochemistry of the Everglades and mangrove sedimentary habitats that create favourable conditions for the retention of mercury and make it available at high concentrations for aquatic predators.

Organohalogenated contaminants in type 2 diabetic serum from Jeddah, Saudi Arabia.

Most of the organohalogenated contaminants (OHCs) have high environmental stability and are lipophilic in nature, thus bioaccumulate through the various routes e.g., inhalation, dermal contact and food intake. Human exposure to these OHCs can induce adverse health effects. Studies on the occurrence of OHCs in human samples from Saudi Arabia are scarce. Therefore, this study aimed at providing preliminary insight on the occurrence of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated biphenyl ethers (PBDEs) in diabetic and non-diabetic donors from KSA. Serum samples were collected from type 2 diabetic patients (n = 40) and control donors (n = 20) to study the impact of OHCs on their health. For the first time we studied the difference of Æ©OHCs in type 2 diabetic and control participants. The order of obtained results was Æ©OCPs (35-650 ng/g lw)> Æ©PCBs (15-90 ng/g lw)> Æ©PBDEs (1.5-68 ng/g lw). The major contributors were p,p'-DDE (median 44 ng/g lw), PCB 153 (2.3 ng/g lw), PCB 138 (2.1 ng/g lw), BDE 153 (1.2 ng/g lw) and BDE 47 (0.85 ng/g lw). Exposure to different OHCs between male and female donors was not significantly different (p > 0.05). However, Æ©PCBs and Æ©OHCs were significantly higher (p < 0.05) in diabetic donors than those of control group. We computed significantly positive correlations (p < 0.05) among different OHCs and between OHCs and age factor. The current study highlights the presence of different OHCs in humans from Jeddah, KSA. This is a preliminary study based on small sample size but our results suggested that detailed studies are required to understand the sources of these pollutants and their impact on human health.

Organohalogenated contaminants in sediments and bivalves from the Northern Arabian Gulf.

Several classes of Organohalogenated contaminants (OHCs) were determined in sediments and bivalves collected from Kuwait coast. The levels and profile of polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) were compared in both sediments and bivalves. PCB-153 and -138 were the major contributors towards total OHCs followed by DDT and its metabolites (DDTs). The higher contribution of DDTs (~40%) and BDE-47 (~15%) in bivalves as compared to that in associated sediments indicated high biota-sediment accumulation factors (BSAF). Higher BSAF (values for heavier PCBs, DDTs and PBDEs) also indicated their high accumulation potential from sediment into associated biota at most of the studied locations. Overall, OHCs in sediments and bivalves measured in current study were lower than those reported in the literature worldwide. Most of the sediment concentrations of OHCs (ng/g, dry weight) were in the range of permissible guideline values proposed by Canadian Sediment Quality Guidelines (CSQGs), with few exceptions for DDTs (5 ng/g) and PCBs (22.7 ng/g). Similarly, 10% of bivalve samples contained high levels (ng/g, lipid weight) of PCBs (300) and DDTs (150) and were above the set safety benchmarks. This study establishes baseline for future monitoring programs.

Current status, between-year comparisons and maternal transfer of organohalogenated compounds (OHCs) in Arctic char (Salvelinus alpinus) from Bjørnøya, Svalbard (Norway).

High levels of organohalogenated compounds (OHCs) have been found in Arctic char from Lake Ellasjøen at Bjørnøya (Svalbard, Norway) compared to char from other arctic lakes. The first aim of the study was to investigate the OHC status, contaminant profile, and partitioning of OHCs between muscle and ovary tissue in spawning female char from the high-polluted Lake Ellasjøen and the low-polluted Lake Laksvatn. The second aim was to investigate if OHC levels in muscle tissue have changed over time. Between-lake comparisons show that the muscle levels (lipid weight) of hexachlorobenzene (HCB), chlordanes (∑CHLs), mirex, dichlorodiphenyltrichloroethanes (∑DDTs) and polychlorinated biphenyls (∑PCBs) were up to 36 times higher in char from Ellasjøen than in Laksvatn, and confirm that the char from Ellasjøen are still heavily exposed compared to char from neighboring lake. A higher proportion of persistent OHCs were found in Ellasjøen compared to Laksvatn, while the proportion of the less persistent OHCs was highest in Laksvatn. A between-year comparison of OHC levels (i.e., HCB, DDTs, PCBs) in female and male char shows higher levels of HCB in female char from Ellasjøen in 2009/2012 compared to in 1999/2001. No other between-year differences in OHC levels were found. Due to small study groups, findings associated with between-year differences in OHC levels should be interpreted with caution. OHCs accumulate in the lipid rich ovaries of spawning females, resulting in up to six times higher levels of OHCs in ovaries compared to in muscle (wet weight). The toxic equivalent (TEQ)-value for the dioxin-like PCBs (PCB-105 and -118) in ovaries of the Ellasjøen char exceeded levels associated with increased egg mortality in rainbow trout (Oncorhynchus mykiss). Hence, we suggest that future studies should focus on the reproductive health and performance abilities of the high-exposed population of char inhabiting Lake Ellasjøen.

Expression of prestin in OHCs is reduced in Spag6 gene knockout mice.

Sperm-associated antigen 6 (Spag6) gene, which encodes an axonemal protein (SPAG6), ubiquitously expresses in tissue and organs containing ciliated cells. The present work was to investigate whether SPAG6 expressed in cochlear hair cells and, if so, to explore the presumable correlations between prestin and SPAG6. The distribution of SPAG6 in organ of Corti and the morphological features of hair cells in basilar membrane were investigated by immunofluorescent staining. The amount of prestin in Spag6 mutant mice was measured by Western blotting and real-time PCR, respectively. Additionally, co-immunoprecipitation tests were performed to confirm the presumed interaction between prestin and SPAG6. We observed that SPAG6 expressed in the cuticular plate in outer hair cells (OHCs) and prestin in the lateral wall of OHCs that located along with SPAG6 at this site. In comparison to Spag6 +/+ mice, Spag6 -/- mice showed apparent morphological abnormity of OHCs and lower intensity of prestin fluorescence. The expression of prestin in Spag6 -/- mice reduced significantly at both protein and mRNA levels. Moreover, co-immunoprecipitation tests demonstrated the interaction between prestin and SPAG6. Taken together, these data indicate that SPAG6 is indispensible for the stability of OHCs by maintaining the normal expression of prestin, which implies that Spag6 gene is essential for mechanosensory function of OHCs.

Lead exposure results in hearing loss and disruption of the cochlear blood-labyrinth barrier and the protective role of iron supplement.

This study was designed to investigate the impact of lead (Pb(2+)) on the auditory system and its molecular mechanisms. Pb(AC)2 was administrated to male SD rats aged 21-22 d for 8 weeks at a dose of 300ppm. Male guinea pigs were also administrated with 50mg/kg Pb(AC)2 two times a week for 8 weeks. The auditory nerve-brainstem evoked responses (ABR) was recorded and the morphological changes of the outer hair cells (OHCs) were observed with Phallodin-FITC staining. In addition, the integrity of the blood-labyrinth barrier was observed by TEM and the expression of tight junction proteins (TJPs) in the cochlear stria vascularis was determined by immunofluorescence. Our results showed that Pb(2+) exposure resulted in increased ABR threshold in both rats and guinea pigs. Abnormal shapes and loss of OHCs were found in the cochlear basilar membrane following the Pb(2+) exposure. TEM study showed that the tight junctions between the endothelial cells and the border cells were lost and disrupted. Down-regulation of the occludin, ZO-1 and claudin-5 in the stria vascularis suggested that the increased permeability of the blood-labyrinth barrier may attribute to the Pb(2+)-induced decrease of TJPs' expression. Additionally, Fe(2+) supplement partly reversed the Pb(2+)-induced hearing loss and down-regulation of TJPs. Taken together, these data indicate that the disruption of blood-labyrinth barrier by down-regulating the expression of TJPs plays a role in the Pb(2+)-induced hearing loss, and Fe(2+) supplement protects the auditory system against Pb(2+)-induced toxicity and may have significant clinical implications.

Temporospatial expression and cellular localization of VGLUT3 in the rat cochlea.

Vesicular glutamate transporter 3 (VGLUT3) plays an important role in hearing, and VGLUT3 knockout mice are deaf. However, the mechanisms whereby VGLUT3 exerts its effects in the cochlea are not well established. Elucidating the developmental and aging dynamics of VGLUT3 localization and expression in the cochlea would aid a functional understanding of auditory glutamatergic transmission. In this study, we characterized the expression of VGLUT3 in rat auditory epithelium and spiral ganglion cells (SGCs) during postnatal development and with age using immunohistochemistry and quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). We observed VGLUT3 expression in cochlea inner hair cells (IHCs) and SGCs as early as postnatally, and its expression increased gradually with maturity. However, the expression of VGLUT3 in the IHCs decreased in the aging rats compared to postnatal day 60 (P60), and VGLUT3 was still expressed in the remaining SGCs in the aging rats. VGLUT3-immunopositive punctate structures were only found in the cytoplasm of SGCs, not IHCs, at P7, or later. Variation in VGLUT3 mRNA expression evaluated by quantitative real time RT-PCR was consistent with the immunohistochemical data except for no statistical difference between P60 and aging rats in the whole cochlea level. Our data suggest that VGLUT3 likely has developmental and physiological roles in the rat cochlea during postnatal development as well as later in life. VGLUT3 may have additional unknown roles in SGCs besides glutamate transport.