Establishment and application of a reverse dot blot assay for 13 mutations of hearing-loss genes in primary hospitals in China

Background

Hearing loss is a common sensorineural dysfunction with a high incidence in China. Although genetic factors are important causes of hearing loss, hearing-related gene detection has not been widely adopted in China.

Objective

Establishing a rapid and efficient method to simultaneously detect hotspot hearing loss gene mutations.

Methods

A reverse dot blot assay combined with a flow-through hybridization technique was developed for the simultaneous detection of 13 hotspot mutations of 4 hearing loss-related genes including GJB2, GJB3, SLC26A4, and the mitochondrial gene MT-RNR1. This method involved PCR amplification systems and a hybridization platform.

Results

The technique can detect 13 hotspot mutations of 4 hearing loss-related genes. And a total of 213 blood samples were used to evaluate the availability of this method.

Discussion

Our reverse dot blot assay was a simple, rapid, accurate, and cost-effective method to identify hotspot mutations of 4 hearing loss-related genes in a Chinese population.

Study on Screening Core Biomarkers of Noise and Drug-Induced Hearing Loss Based on Transcriptomics

Background  Noise and drug-induced hearing loss (HL) is becoming more and more serious, but the integration and analysis based on transcriptomics and proteomics are lacking. On the one hand, this study aims to integrate existing public transcriptomic data on noise and gentamicin-induced HL. On the other hand, the study aims to establish the gentamicin and noise-induced HL model of guinea pigs, then to perform the transcriptomic and proteomic analyses. Through comprehensive analysis of the above data, we aim to screen, predict, and preliminarily verify biomarkers closely related to HL. Material and Methods  We screened the Gene Expression Omnibus database to obtain transcriptome data expression profiles of HL caused by noise and gentamicin, then constructed the guinea pig HL model and perform the transcriptomic and proteomic analyses. Differential expression and enrichment analysis were performed on public and self-sequenced data, and common differentially expressed genes (DEGs) and signaling pathways were obtained. Finally, we used proteomic data to screen for common differential proteins and validate common differential expression genes for HL. Results  By integrating the public data set with self-constructed model data set, we eventually obtained two core biomarkers of HL, which were RSAD2 and matrix metalloproteinase-3 (MMP3). Their main function is to regulate the development of sense organ in the inner ear and they are mainly involved in mitogen-activated protein kinase and phosphoinositol-3 kinase/protein kinase B signaling pathways. Finally, by integrating the proteomic data of the self-constructed model, we also found differential expression of MMP3 protein. This also preliminarily and partially verified the above-mentioned core biomarkers. Conclusion and Significance  In this study, public database and transcriptomic data of self-constructed model were integrated, and we screened out two core genes and various signal pathways of HL through differential analysis, enrichment analysis, and other analysis methods. Then, we preliminarily validated the MMP3 by proteomic analysis of self-constructed model. This study pointed out the direction for further laboratory verification of key biomarkers of HL, which is of great significance for revealing the core pathogenic mechanism of HL.

[A cross-sectional survey and analysis of influencing factors of humanistic of the current status of humanistic care ability of burn specialist nurses]

Objective: To investigate the current status of humanistic care ability of burn specialist nurses and to analyze the influencing factors. Methods: A single-center cross-sectional research method was conducted. From May to August 2020, 63 burn specialist nurses who met the inclusion criteria in Ruijin Hospital affiliated to Shanghai Jiao Tong University School of Medicine were selected. Self-made general data questionnaire was used to investigate 17 indexes, including gender, age, professional title, working years, whether received humanistic care training, academic qualification, and caring ability inventory (CAI) was used to evaluate their humanistic care ability. After the nurses were classified by the general data, independent sample t test and one-way analysis of variance were performed on the data to analyze the total score of CAI. The CAI total scores and scores of cognition, courage, and patience of the nurses were compared with the international norm. The factors with statistically significant differences in unvariate analysis were selected for multiple linear regression analysis to screen the independent influencing factors of humanistic care ability of burn specialist nurses. Results: A total of 63 questionnaires were collected in this survey, all of which were valid. Among the 63 nurses, there were 4 males and 59 females, with the age mainly ranging from 20 to 30 years (30 nurses, 47.62%), the professional titles mainly being nurse practitioner (36 nurses, 57.14%), the working years mainly being more than 10 years (28 nurses, 44.44%), 32 nurses not receiving humanistic care training, and academic qualifications mostly being junior college (37 nurses, 58.73%). There were significant differences in the total scores of CAI among nurses with different ages, professional titles, working years, whether received humanistic care training, and academic qualifications (with F values of 53.95, 49.14, and 75.42, t values of 6.08 and -2.82, respectively, P<0.01). The scores of cognition, courage, and patience and the total scores of CAI of nurses in this group were significantly lower than those of international norm (with t values of -2.02, -2.04, -6.19, and -3.89, respectively, P<0.05 or P<0.01). Multiple linear regression analysis showed that age, working years, professional title, and whether received humanistic care training were the independent influencing factors of humanistic care ability of burn specialist nurses (with 95% confidence intervals of 1.91-23.23, 16.25-31.48, 1.05-19.09, and 6.72-31.82, unstandardized coefficient values of 12.57, 23.86, 10.07, and 19.27, respectively, P<0.05 or P<0.01). Conclusions: The humanistic care ability of burn specialist nurses is relatively weak. Age, professional title, working years, and whether received humanistic care training are the independent influencing factors of humanistic care ability of burn specialist nurses.

[Some HBeAg-negative chronic hepatitis B patients treated with nucleos(t)ide analogue can achieve HBsAg loss after drug withdrawal: stop-to-cure may be coming]

Nucleoside/Nucleotide analogues (NAs) are widely used for the antiviral treatment of chronic hepatitis B (CHB), however, it is difficult to achieve serum hepatitis B surface antigen (HBsAg) loss with NAs therapy. In recent years, several prospective trails have reported that HBsAg loss (functional cure or clinical cure) also occurs in a small number of hepatitis B e antigen (HBeAg) negative CHB patients who discontinued long-term treatment with NAs. Accordingly, the "stop-to-cure" strategy is proposed. Although the mechanism has not been fully elucidated, the known factors related to serum HBsAg loss with NAs withdrawal include HBV genotype, duration of NAs treatment, serum HBsAg and HBV RNA levels at end-of-treatment, and ethnic differences. In the review, we discuss the best time to stop NAs therapy, the potential markers for predicting relapse after cessation of NAs and the possible mechanism of "stop-to-cure" in HBeAg-negative CHB patients, and propose some suggestions on the time of retreatment.

[Characteristics and regulatory mechanisms of lipid metabolism remodeling after malignant transformation of glioma-associated macrophages]

Objective: To observe the lipid metabolism characteristics of tumor-associated macrophages (TAM) after malignant transformation in the glioma micro-environment, and analyze the biological phenotype changes and regulatory mechanisms after inhibiting the lipid metabolism remodeling. Methods: Twelve male Balb/c mice of 6-8 weeks were used in the study. Macrophages (Mφ) were derived from mouse bone marrow, and malignantly transformed macrophages (tMφ₁ and tMφ₂) were cloned from the model of glioma stem cell (GSC) through interaction with Mφ in vivo and in vitro. Intracellular lipid droplet formation and cellular cholesterol content were measured respectively in Mφ, tMφ₁ and tMφ₂. qRT-PCR was performed to detect the genes expression level related with lipid metabolism, including sterol regulatory element binding protein (SREBP), fatty acid synthase (FASN), and 3-hydroxy-3-methylglutarate monoacyl coenzyme A reductase (HMG-CoA). Simvastatin (SIM) was used to analyze the proliferation, immigration and invasiveness ability in tMφ₁ and tMφ₂ after inhibition of the lipid metabolism. Differential expression profiles of miRNAs after SIM treatment were constructed in t-Mφ₁ and bio-informatics analysis was screened and verified for miR449a and its target gene sorting micro-tubule connectin 17 (SNX17) associated with lipid metabolism remodeling. The effect on SNX17 by up-regulated miR-449a were analyzed by qRT-PCR and Western blot, meanwhile, the biological phenotype and cholesterol content were observed after up-regulation of miR449a. Low-density lipoprotein receptor (LDLR) protein levels after SNX17 knockdown and intracellular cholesterol content after LDLR knockdown were detected respectively. Results: The numbers of intracellular lipid droplet formation in tMφ₁ and tMφ₂ were more than that in Mφ (P<0.001). Likewise, the relative contents of cholesterol (3.89±0.68 and 3.56±0.53), SREBP (4.78±0.60 and 2.84±0.41), FASN (4.65±0.70 and 3.01±0.45), and HMG-CoA (5.74±0.55 and 2.97±0.34) were significantly higher in tMφ₁ and tMφ₂ than those of Mφ (1.01 wel, 1.02 wel and 0.99 wel, respectively) (all P<0.001). The proliferation rates of tMφ₁ and tMφ₂ decreased from (47.06±5.88) % and (45.29±5.64)% to (23.53±4.70)% and (18.74±5.76)%, respectively after treatment with SIM (both P<0.05). The numbers of migrated cells decreased from 1 025±138 and 350±47 to 205±63 and 99±25, respectively (both P<0.001). And the numbers of invasiveness cells decreased from 919±45 and 527±34 to 220±23 and 114±21, respectively (both P<0.001). While the relative intracellular cholesterol content decreased to 0.52±0.08 and 0.58±0.07 (both P<0.05), respectively. MiR-449a was screened from tMφ₁ by SIM, and the target gene was analyzed and verified to be SNX17. SNX17 expression was down-regulated, and the proliferation rate, the number of migration and invasiveness was significantly decreased after miR-449a over-expression (all P<0.05). Low-density lipoprotein receptor (LDLR) expression was down-regulated after knock-down of SNX17, while the cholesterol content was decreased after knock-down of LDLR in tMφ₁ and tMφ₂ (all P<0.05). Conclusions: Malignantly transformed TAMs undergo lipid metabolism remodeling characterized with enhanced lipid metabolism. MiR-449a regulates the LDLR by targeting SNX17, thereby affecting the lipid metabolism of malignantly transformed macrophages, and subsequently inhibiting its proliferation, migration, and invasion ability. Precise intervention with miR-449a/SNX17/LDLR axis could provide an experimental basis for reversing its tumor-promoting micro-environment remodeled by GSC through metabolic intervention.

[Preparation and effect against cervical cancer invasion in vitro of harmine-loaded photosensitive liposomes]

Despite the development of HPV vaccines and screening programs, cervical cancer is still a serious threat to women's health. Early-stage cervical cancer is mainly treated by surgery. However, considering the serious complications after surgery, hyperthermia is recommended to enhance the effect of chemotherapy, retain the integrity of cervix, improve the treatment effect, which provides a therapeutic basis for the early treatment of cervical cancer. The photosensitive liposomes containing harmine and dye IR-780 were prepared by thin-film dispersion method and separated by Sephadex G-50 dextran gel column. The preparation conditions were optimized as the mass ratio of phospholipid to cholesterol membrane material being 8∶1 and that of drug to lipid being 1∶20. The results of HPLC showed that the encapsulation efficiency of harmine was 55.6%±0.18%. The prepared photosensitive liposomes were round and evenly distributed under transmission electron microscope, with the particle size of(125.2±0.62) nm determined by Marvin particle size analyzer and the Zeta potential of(-2.55±0.76) mV. Additionally, the photosensitive liposomes had the photothermal conversion efficiency, an important property of photothermal agent, of 27.1%±0.86%. The photosensitive liposomes stored at 4 ℃ showed stable encapsulation efficiency in the first 14 days without flocculation. The sulforhodamine B(SRB) assay was employed to determine the inhibitory effect of the liposomes on the proliferation of HeLa cells under near-infrared(NIR) irradiation or not, which showcased stronger inhibitory effect under NIR irradiation. The results of Transwell assay indicated that the prepared liposomes significantly inhibited the invasion and migration of HeLa cells in vitro. The findings of this study provide a basis for the treatment of cervical cancer with harmine.

[Effect of Sishen Pills and its split prescriptions on Tfr/Tfh9/Tfh17 cells in colitis mice]

This study aims to investigate the regulatory effect of Sishen Pills(SSP) and its split prescriptions Ershen Pills(EP) and Wuweizi Powder(WP) on T follicular helper(Tfh) cell subset in the dextran sodium sulfate(DSS)-induced colitis mice and the mechanism. A total of 60 male SPF BALB/c mice were used, 10 of which were randomly selected as the normal group. The rest 50 were induced with 3% DSS solution for colitis modeling. After modeling, they were randomized into 5 groups: model group, SSP group, EP group, WP group, and mesalazine group. Body mass, colon mass, colon mass index, colon length, and unit colon mass index in each group were observed. After hematoxylin-eosin(HE) staining, the pathological injury of colon tissue was scored. The expression levels of molecules related to the STAT/SOCS signaling pathway in colon tissues were analyzed by Western blot. Differentiation levels of Tfh cells such as CD4~+CXCR5~+IL-9~+(Tfh9), CD4~+CXCR5~+IL-17~+(Tfh17), and CD4~+CXCR5~+Foxp3~+(Tfr) in peripheral blood of mice were detected by flow cytometry. The results showed each treatment group demonstrated significant increase in body mass and colon length, decrease in colon mass, colon mass index, unit colon mass index, and histopathological score(P<0.05, P<0.01), reduction of the expression of p-STAT3, STAT3, p-STAT6, and STAT6(P<0.05, P<0.01), rise of the expression of SOCS1 and SOCS3(P<0.05, P<0.01), decrease of Tfh9 and Tfh17 cells, and increase of Tfr cells(P<0.05, P<0.01) compared with the model group. These results indicated that SSP and the split EP and WP may alleviate ulcerative colitis by inhibiting the activation of STAT/SOCS signaling pathway and regulating the balance of Tfr/Tfh9/Tfh17 cells.

Curcumin Inhibits T Follicular Helper Cell Differentiation in Mice with Dextran Sulfate Sodium (DSS)-Induced Colitis

Follicular helper T cells (Tfh) regulate the differentiation of germinal center B cells and maintain humoral immunity. Notably, imbalances in Tfh differentiation often lead to the development of autoimmune diseases, including inflammatory bowel disease (IBD). Curcumin, a natural product derived from Curcuma longa, is effective in relieving IBD in humans and animals, and its mechanisms of immune regulation need further elaboration. In this study, dextran sodium sulfate induced ulcerative colitis in BALB/c mice, and curcumin was administered simultaneously for 7 days. Curcumin effectively upregulated the change rate of mouse weight, colonic length, down-regulated colonic weight, index of colonic weight, colonic damage score and the levels of pro-inflammatory cytokines IL-6, IL-12, IL-23 and TGF-[Formula: see text]1 in colonic tissues of colitis mice. Importantly, curcumin regulated the differentiation balance of Tfh and their subpopulation in colitis mice; the percentages of Tfh (CD4[Formula: see text]CXCR5[Formula: see text]BCL-6[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]PD-1[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]PD-L1[Formula: see text], CD4[Formula: see text]CXCR5[Formula: see text]ICOS[Formula: see text], Tfh17 and Tem-Tfh were downregulated significantly, while CD4[Formula: see text]CXCR5[Formula: see text]Blimp-1[Formula: see text], Tfh1, Tfh10, Tfh21, Tfr, Tcm-Tfh and Tem-GC Tfh were upregulated. In addition, curcumin inhibited the expression of Tfh-related transcription factors BCL-6, p-STAT3, Foxp1, Roquin-1, Roquin-2 and SAP, and significantly upregulated the protein levels of Blimp-1 and STAT3 in colon tissue. In conclusion, curcumin may be effective in alleviating dextran sulfate sodium-induced colitis by regulating Tfh differentiation.

[Associations between adverse childhood experiences and adulthood substance use among lesbians]

Objective: To investigate the associations between adverse childhood experiences (ACE) and substance use behaviors among lesbians to provide a scientific basis for high-risk population identification and formulation of targeted intervention measures. Methods: Lesbians who participated in routine AIDS voluntary counseling, testing services, activities, and peer recommendations were recruited from July to December 2018, with the help of LesPark in Beijing. Convenient sampling method was used. Demographic characteristics, ACE, and substance use behaviors of subjects were investigated using an online platform powered by www.wjx.cn. Subsequently, the associations between ACE and adulthood substance use behaviors were evaluated using the logistic regression model. The SPSS 22.0 was used for statistical analysis. Results: A total of 294 lesbians were recruited in the study, 81.3% (239/294) of them were lesbians, and 18.7% (55/294) were bisexuals. Besides, 55.8% (164/294) of subjects reported they had had ACE, with proportions of lesbians experiencing abuse, neglect, and family dysfunction as 33.3% (98/294), 24.5% (72/294), and 32.7% (96/294), respectively. 55.1% (162/294) of the lesbians reported they had smoked in the past 30 days, 11.2% (33/294) reported having drug-use behavior in the past three months, and 22.8% (67/294) claimed drinking alcohol weekly. Multivariate logistic regression analysis showed that lesbians with ACE were at high risks to smoke (OR=1.87, 95%CI: 1.13-3.08), drink (OR=2.13, 95%CI: 1.18-3.84), and use drugs (OR=3.33, 95%CI: 1.29-8.61) in adulthood. Moreover, lesbians with childhood family dysfunction were at higher risk of smoking cigarettes (OR=2.60, 95%CI: 1.46-4.62) and drinking alcohol (OR=2.65, 95%CI: 1.44-4.87). At the same time, those with abuse experience were at higher risk of drug use (OR=3.17, 95%CI: 1.26-7.96). Conclusions: Substance use behaviors, including cigarette smoking, drinking alcohol, and drugs use, were common among lesbians. Positive associations were found between ACE and adulthood substance use behaviors.

Involvement of NLRP3-inflammasome pathway in noise-induced hearing loss

The inflammasome is a multiprotein oligomer in the cell cytoplasm and is part of the innate immune system. It plays a crucial role in the pathological process of noise-induced hearing loss (NIHL). However, the mechanisms of NLR family pyrin domain containing 3 (NLRP3) inflammasome activation in NIHL have not been clearly demonstrated. In this study, miniature pigs were exposed to white noise at 120 dB(A) and auditory brainstem response measurements were used to measure their hearing function. Immunofluorescence staining, confocal laser scanning microscopy, western blot assay, and quantitative reverse transcription-polymerase chain reaction were used to analyze inflammasome-related protein distribution and expression. NLRP3, interleukin-1β, interleukin-18, and cleaved-caspase-1 were highly expressed in the cochlea after 120 dB(A) white noise exposure. Our findings suggest that NLRP3-inflammasomes in the cochlea may be activated after acoustic trauma, which may be an important mechanism of noise-induced hearing loss.

The value of multidisciplinary team in syncope clinic for the effective diagnosis of complex syncope

BACKGROUND

Syncope is a perplexing challenge that often receives thorough evaluation, yet the diagnosis remains unclear. Usually, the emergency department is the first point at which patients present with syncope. However, diverse medical factors, including low diagnostic rates and inconsistent management by doctors, add to healthcare costs and delay diagnosis for syncope patients.

METHODS

Patients who had been to the emergency department at least once but were not given a clear diagnosis of syncope were recruited into our study at the time they visited syncope clinic staffed by a multidisciplinary team. Complete medical histories and clinical examinations were conducted by both experienced cardiologists and neurologists. If patients were not given a conclusive diagnosis at the syncope clinic on the basis of outpatient examinations, they were admitted for further evaluation.

RESULTS

A total of 209 consecutive patients claiming "syncope" visited the syncope clinic, yet only 167 patients were formally diagnosed with syncope. For these 167 patients, the mean age was 55.93 ± 17.40 years old, and 41.3% were male. The proportions of cardiac syncope, reflex syncope, orthostatic hypotension (OH), and syncope of uncertain etiology were 19.8%, 64.1%, 7.8%, and 8.4%, respectively. The diagnostic rate was 91.6%, and the hospitalization rate was 23.4%. Patients with reflex syncope and OH were younger than patients with cardiac syncope. Cardiac syncope tends to occur more frequently in males, while reflex syncope is more likely in females.

CONCLUSIONS

The cooperation of professional cardiologists and neurologists will play an important role in improving diagnostic rates, lowering admission rates, and reducing medical costs.

Establishment of a Large Animal Model for Eustachian Tube Functional Study in Miniature Pigs

This study was performed to investigate whether miniature pigs are a suitable animal model for studies of the Eustachian tube (ET). Sixteen Chinese experimental miniature pigs were used in this investigation. Ten animals were used for anatomical and morphometric analyses to obtain qualitative and quantitative information regarding the ET. Three animals were used for histological analysis to determine the fine structure of ET cross-sections. Three animals were used to investigate the feasibility of balloon dilation of the Eustachian tube (BDET). The anatomical study indicated that the pharyngeal orifice and tympanic orifice of the miniature pig ET are located at the posterior end of the nasal lateral wall and anterior wall of the middle ear cavity, respectively. The cartilaginous tube was seen to pass through the whole length of the ET, the length of the cartilaginous part of the ET and the diameter of the isthmus were similar between humans and miniature pigs. The inclination of the ET in miniature pigs was larger than that in humans. The gross histology seemed to be slightly different between miniature pig and human, but the fine structures were essentially the same in both species. BDET experiments verified that the miniature pig model is suitable as a model for clinical operations. The miniature pig ET corresponds very well to that of humans. In addition, the miniature pig ET is suitable as a model for clinical operations. Therefore, the miniature pig is a valid animal model for ET study. Anat Rec, 302:1024-1038, 2019. © 2019 Wiley Periodicals, Inc.

Degeneration of saccular hair cells caused by MITF gene mutation

Background

Waardenburg syndrome (WS) is the consequence of an inherited autosomal dominant mutation which causes the early degeneration of intermediate cells of cochlear stria vascularis (SV) and profound hearing loss. Patients with WS may also experience primary vestibular symptoms. Most of the current WS studies did not discuss the relationship between WS and abnormal vestibular function. Our study found that a spontaneous mutant pig showed profound hearing loss and depigmentation. MITF-M, a common gene mutation causes type WS which affect the development of the intermediate cell of SV, was then identified for animal modeling.

Results

In this study, the degeneration of vestibular hair cells was found in pigs with MITF-M. The morphology of hair cells in vestibular organs of pigs was examined using electron microscopy from embryonic day E70 to postnatal two weeks. Significant hair cell loss in the mutant saccule was found in this study through E95 to P14. Conversely, there was no hair cell loss in either utricle or semi-circular canals.

Conclusions

Our study suggested that MITF-M gene mutation only affects hair cells of the saccule, but has no effect on other vestibular organs. The study also indicated that the survival of cochlear and saccular hair cells was dependent on the potassium release from the cochlear SV, but hair cells of the utricle and semi-circular canals were independent on SV.

Key Genes and Pathways Associated With Inner Ear Malformation in SOX10 p.R109W Mutation Pigs

SRY-box 10 (SOX10) mutation may lead to inner ear deformities. However, its molecular mechanisms on inner ear development are not clear. In this work, the inner ear morphology was investigated at different embryonic stages of the SOX10 mutation miniature porcine model with sensorineural hearing loss, and high-throughput RNA-seq and bioinformatics analyses were applied. Our results indicated that the SOX10 mutation in the miniature pigs led to an incomplete partition (IP) of the cochlea, a cystic apex caused by fusion from middle and apical turns, cochlear modiolar defects and a shortened cochlear duct. The model demonstrated 173 differentially expressed genes (DEGs) and 185 differentially expressed long non-coding RNAs (lncRNAs). The down-regulated DEGs most significantly enriched the inflammatory mediator regulation of the TRP channels, arachidonic acid metabolism, and the salivary secretion pathways, while the up-regulated DEGs most significantly enriched the systemic lupus erythematosus and alcoholism pathways. Based on gene cluster analysis, we selected four gene groups: WNT1, KCNQ4, STRC and PAX6.

Inner ear structure of miniature pigs measured by multi-planar reconstruction techniques

To study the structures of the scala vestibuli and tympani of miniature pigs in order to evaluate the feasibility of using miniature pigs as the animal model for cochlear implant. The temporal bones of three miniature pigs with normal hearing were scanned by micro-CT. With the aid of the Mimics software, we reconstructed the 3D structure of inner ear basing on the serial images of the miniature pig, and obtained dimensions of the scala vestibuli and tympani with multi-planar reconstruction (MPR) technique. The constructed slicing images displayed the fine structures of the cochlea. The results of our study showed that the cross-sectional areas of the scala tympani were greatest at 2.67 ± 0.90 mm² when the circumferential length from the starting point of basal turn of the cochlea reached to 1.16 mm. The scala vestibuli has a largest width and height at the starting point of basal turn. The width and the height were 2.65 ± 0.45 mm and 2.43 ± 0.2 mm respectively. The largest width and height of the scala tympani were 2.17 ± 0.30 mm and 1.83 ± 0.42 mm. The result of our study suggests that the cochlea of miniature pigs is highly consistent with human's. Miniature pigs may be used as a new model for cochlear implant. MPR technique may be used as a new approach to obtain further information of patient's cochlea in surgeons which is helpful to select suitable cochlear implant devices and surgery approach.

A hypothesis study on bionic active noise reduction of auditory organs

BACKGROUND

Noise exposure can lead to hearing loss and multiple system dysfunctions. As various forms of noise exist in our living environments, and our auditory organs are very sensitive to acoustic stimuli, it is a challenge to protect our hearing system in certain noisy environments.

PRESENTATION OF THE HYPOTHESIS

Herein, we propose that our hearing organ could serve as a noise eliminator for high intensity noise and enhance acoustic signal processing abilities by increasing the signal-noise ratio. For suprathreshold signals, the hearing system is capable of regulating the middle ear muscles and other structures to actively suppress the sound level to a safe range.

TESTING THE HYPOTHESIS

To test our hypothesis, both mathematic model analyses and animal model studies are needed. Based on a digital 3D reconstructed model, every structure in the auditory system can be analyzed and tested for its contribution to the process of noise reduction. Products manufactured by this bionic method could be used and verified in animal models and volunteers.

IMPLICATIONS

By mimicking the noise-reduction effect of the sophisticated structures in the hearing system, we may be able to provide a model that establishes a new active-sound-suppression mode. This innovative method may overcome the limited capabilities of current noise protection options and become a promising possibility for noise prevention.

[Early physical growth and disease analysis among children born delivered by HBsAg-positive mothers]

Objective: To estimate the early physical growth and disease in children born to HBsAg-positive mothers. Methods: This was a retrospective cohort study. Three areas as Xihu in Hangzhou, Lanxi in Jinhua, and Haiyan in Jiaxing in Zhejiang province were selected by cluster sampling. The growth outcomes of children born to HBsAg-positive mothers (exposure group) and matched 1∶1 women uninfected with HBV (control group) in 2014 were investigated and compared at birth, 6, 9, 12, and 18 months, respectively. There were totally 342 children in each group. Results: The incidences of low birth weight (LBW) for children born to exposure and control group were 1.8% (6/342), and 2.6% (9/342), respectively (P=0.433); and, rates of preterm birth were 2.3% (8/342), and 2.0% (7/342), respectively (P=0.794). The mean birth weight of children born to mothers without HBV infection (3.4±0.4) kg was dramatically higher than children in exposure group (3.3±0.4) kg (P=0.019). At 18 months, the average head circumference was significantly greater among children in control group (47.3±1.3) cm than children in exposure group (47.0±2.0) cm (P=0.038). Additional, mean birth weeks, height, weight, increases in height/weight/head circumference each month, weight/height/head circumference for age Z scores, proportion of growth retardation and low weight, disease prevalence were not observed statistically differences between two groups (P>0.05). All children born to HBsAg-positive mothers were received three-dose HBV vaccination. The rate of hepatitis B immunoglobulin for births born to HBsAg-positive was 98.8% (338/342). Mother to children transmission of HBV at 18 months was 1.0% (1/97). Conclusion: No significant differences in growth development and disease prevalence were found among children born to HBsAg-positive women and women without HBV infection.

Comparison of Nitrosospira strains isolated from terrestrial environments

Most of our knowledge about the physiology of ammonia-oxidizing bacteria is based on experiments with Nitrosomonas europaea, which appears to be less ubiquitous than Nitrosospira. We have isolated Nitrosospiras from widely different environments and compared their specific growth rate, substrate affinity, urease activity, temperature response, pH tolerance and cell morphology. Two of the strains had a variable morphology: the spirals were less tightly coiled than the classical Nitrosospira type and a fraction of the culture had a vibrioid appearance. These vibrioid strains were also peculiar in having a much higher apparent activation energy for ammonia monooxygenase (AMO) (129 and 151 kJ mol(-1)) than that of the more classical Nitrosospiras (78 and 79 kJ mol(-1)). The differences in morphology and activation energy were congruent with the phylogeny of the genes for 16S rRNA (Utåker et al., System. Appl. Microbiol. 18) and AMO. The response to pH in the medium was investigated for four strains. The oxidation rate at the onset of the pH exposure experiment was found to obey classical steady state enzyme kinetics, assuming that NH(3) (not NH(4)(+)) is the rate-limiting substrate. The calculated half saturation constants (K(s)) for AMO were 6-11 µM NH(3). Growth had a narrower pH range than oxidation activity and appeared to be restricted by pH-dependent factors other than NH(3). All the isolated strains were urease positive, with a specific urease activity ranging from 60 to 158% of their specific AMO activity. The urease activity was unaffected by acetylene inhibition of the energy metabolism. The substrate affinity for one strain was found to be around 670 µM.

Nitrous oxide production and methane oxidation by different ammonia-oxidizing bacteria

Ammonia-oxidizing bacteria (AOB) are thought to contribute significantly to N2O production and methane oxidation in soils. Most of our knowledge derives from experiments with Nitrosomonas europaea, which appears to be of minor importance in most soils compared to Nitrosospira spp. We have conducted a comparative study of levels of aerobic N2O production in six phylogenetically different Nitrosospira strains newly isolated from soils and in two N. europaea and Nitrosospira multiformis type strains. The fraction of oxidized ammonium released as N2O during aerobic growth was remarkably constant (0.07 to 0.1%) for all the Nitrosospira strains, irrespective of the substrate supply (urea versus ammonium), the pH, or substrate limitation. N. europaea and Nitrosospira multiformis released similar fractions of N2O when they were supplied with ample amounts of substrates, but the fractions rose sharply (to 1 to 5%) when they were restricted by a low pH or substrate limitation. Phosphate buffer (versus HEPES) doubled the N2O release for all types of AOB. No detectable oxidation of atmospheric methane was detected. Calculations based on detection limits as well as data in the literature on CH4 oxidation by AOB bacteria prove that none of the tested strains contribute significantly to the oxidation of atmospheric CH4 in soils.