[Identification of novel pathogenic variants of TRIOBP gene in a pedigree affected with non-syndromic deafness].

OBJECTIVE: To explore the genetic basis for a Chinese pedigree affected with non-syndromic hearing loss (NSHL). METHODS: Commercialized gene chip was applied to detect common mutations associated with congenital deafness. Whole exome sequencing was carried out for patients for whom gene chip yielded a negative result. Candidate variants were verified by Sanger sequencing. RESULTS: Two patients from the pedigree were discovered to carry compound heterozygous variants of the TRIOBP gene, namely c.3299C>A and c.5185-2A>G. Their parents had normal hearing and were both heterozygous carriers of the above variants. Both variants had co-segregated with the disease phenotype in the pedigree and were unreported previously. CONCLUSION: Pathogenic variants of the TRIOBP gene comprise an important factor for NSHL. The novel c.5185-2A>G and c.3299C>A variants discovered in this study have enriched the mutational spectrum of the TRIOBP gene and enabled molecular diagnosis and genetic counseling for the family.

[Resistance surveillance of major pathogens for adult community-acquired respiratory tract infections in China: a multicenter study 2012].

OBJECTIVE: To investigate antimicrobial resistance among pathogens responsible for adult community-acquired respiratory tract infections from 11 hospitals of China. METHODS: From January to December 2012, a total of 599 strains causing adult community-acquired respiratory tract infection were collected from 11 hospitals, including 381 Streptococcus pneumonia, 137 Haemophilus influenza, and 81 Moraxella catarrhalis. The minimal inhibitory concentration (MIC) of antibacterial agents was determined by agar dilution method. RESULTS: Of all the strains, 50% (300/599 strains) were from adults more than 60 years old and only 16.2% (97/599 strains) were from patients aged less than 40 years. According to oral penicillin breakpoints, 56.7% (216/381 strains) of Streptococcus pneumoniae were penicillin non-susceptible strains (PNSSP). More than 90% (345/381 strains) and 39.9% (152/381 strains)-50.7% (193/381 strains) of Streptococcus pneumoniae were resistant to macrolides and oral cephalosporins respectively, but over 97.8% (372/381 strains) and 99% (377/381 strains) were susceptible to levofloxacin and moxifloxacin. PNSSP strains exhibited significant higher resistance to ceftriaxone, amoxicillin/clavulanate, cefaclor and cefuroxime compared with penicillin susceptible Streptococcus pneumoniae (PSSP). The susceptibility rates of Haemophilus influenza to the antimicrobial agents were over 90% except for ampicillin (71.5%, 272/381 strains) and cefaclor (75.2%, 286/381 strains). The prevalence of ß-lactamase positive Haemophilus influenza were 21.9% (30/137 strains), and ß-lactamase positive Haemophilus influenza strains were more resistant to ampicillin, cefaclor, chloramphenicol and tetracycline compared with ß-lactamase-negative strains. Moraxella catarrhalis strains were extremely susceptible to all the antimicrobial agents tested except for clindamycin, azithromycin and clarithromycin. CONCLUSIONS: The activities of macrolides and oral cephalosporins against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis were limited. Levofloxacin and moxifloxacin exhibited good activities against Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis.

Aptamer Sensors for the Detection of Antibiotic Residues- A Mini-Review.

Food security is a global issue, since it is closely related to human health. Antibiotics play a significant role in animal husbandry owing to their desirable broad-spectrum antibacterial activity. However, irrational use of antibiotics has caused serious environmental pollution and food safety problems; thus, the on-site detection of antibiotics is in high demand in environmental analysis and food safety assessment. Aptamer-based sensors are simple to use, accurate, inexpensive, selective, and are suitable for detecting antibiotics for environmental and food safety analysis. This review summarizes the recent advances in aptamer-based electrochemical, fluorescent, and colorimetric sensors for antibiotics detection. The review focuses on the detection principles of different aptamer sensors and recent achievements in developing electrochemical, fluorescent, and colorimetric aptamer sensors. The advantages and disadvantages of different sensors, current challenges, and future trends of aptamer-based sensors are also discussed.

Label-free hairpin-like aptamer and EIS-based practical, biostable sensor for acetamiprid detection.

Acetamiprid (ACE) is a kind of broad-spectrum pesticide that has potential health risk to human beings. Aptamers (Ap-DNA (1)) have a great potential as analytical tools for pesticide detection. In this work, a label-free electrochemical sensing assay for ACE determination is presented by electrochemical impedance spectroscopy (EIS). And the specific binding model between ACE and Ap-DNA (1) was further investigated for the first time. Circular dichroism (CD) spectroscopy and EIS demonstrated that the single strand AP-DNA (1) first formed a loosely secondary structure in Tris-HClO4 (20 mM, pH = 7.4), and then transformed into a more stable hairpin-like structure when incubated in binding buffer (B-buffer). The formed stem-loop bulge provides the specific capturing sites for ACE, forming ACE/AP-DNA (1) complex, and induced the RCT (charge transfer resistance) increase between the solution-based redox probe [Fe(CN)6]3-/4- and the electrode surface. The change of ΔRCT (charge transfer resistance change, ΔRCT = RCT(after)-RCT(before)) is positively related to the ACE level. As a result, the AP-DNA (1) biosensor showed a high sensitivity with the ACE concentration range spanning from 5 nM to 200 mM and a detection limit of 1 nM. The impedimetric AP-DNA (1) sensor also showed good selectivity to ACE over other selected pesticides and exhbited excellent performance in environmental water and orange juice samples analysis, with spiked recoveries in the range of 85.8% to 93.4% in lake water and 83.7% to 89.4% in orange juice. With good performance characteristics of practicality, sensitivity and selectivity, the AP-DNA (1) sensor holds a promising application for the on-site ACE detection.

Validated method for determination of eight banned nitroimidazole residues in natural casings by LC/MS/MS with solid-phase extraction.

A sensitive method based on solid-phase extraction-liquid chromatography-tandem mass spectrometry interfaced with electrospray ionization (SPE-LC-MS/MS-ESI) was developed for the simultaneous determination of 8 banned nitroimidazole (NOZ) drugs including metronidazole (MNZ), ronidazole (RNZ), dimetridazole (DMZ), tinidazole, ornidazole, secnidazole, metronidazole-OH (MNZOH, the metabolite of MNZ), and 2-hydroxymethyl-1-methyl-5-nitroimidazole (HMMNI, the metabolite of RNZ and DMZ) in natural casings. After extraction with ethyl acetate and evaporation, the NOZs were reconstituted in ethyl acetate and purified on a strong cation-exchange SPE column, and then LC/MS/MS analysis was performed by positive ESI applying multiple reaction monitoring of 2 transition reactions for each compound. The method was validated according to the European Union requirements (Commission Decision 2002/657/EC). Specificity, linearity, decision limit (CCalpha), detection capability (CCbeta), accuracy, and precision were determined. Average recoveries of the 8 NOZs from natural animal casing fortified at 3 levels (0.1, 0.5, and 1 microg/kg) ranged from 87.3 to 116.5%. The calculated CCalpha for NOZs ranged from 0.029 to 0.049 microg/kg, and CCbeta ranged from 0.049 to 0.083 microg/kg. Repeatability was in the range of 3.35-10.1%, and within-laboratory reproducibility was <10.3%.

[The value of otolith function test in the prognosis of sudden sensorineural hearing].

OBJECTIVE: To evaluate the characteristics and prognosis of sudden sensorineural hearing loss through vestibular evoked myogenic potentials. METHOD: Fifty patients with unilateral sudden hearing loss underwent an ear test battery, including audiometry, cervical vestibular evoked myogenic potential (cVEMP) and ocular vestibular evoked myogenic potential(oVEMP). The cVEMP and oVEMP in patients with sudden sensorineural hearing loss were investigated. Their associations with initial hearing threshold, the type of audiogram, the results of coloric test and hearing recovery were also accessed. RESULT: After one-month treatment, the average threshold declined significantly in affected ears, with normal VEMP rates improved significantly (P < 0.05). Initial hearing threshold and hearing recovery were significantly associated with the results of coloric test and the results of VEMP test (P < 0.05). CONCLUSION: Our study indicated that vestibular evoked myogenic potential examination was not only a useful additional diagnostic tool in the neurotological evaluation of patients suffering sudden hearing loss, but also very valuable in the prognosis of sudden sensorineural hearing loss.

[Correlation of diffusion tensor imaging between the cerebral cortex and speech discrimination in presbycusis].

OBJECTIVE: To investigate the relationship between pure-tone average (PTA), the fractional anisotropy (FA) of the auditory pathway, cognitive cortex and auditory cortex in presbycusis. METHOD: Twenty-five elderly subjects with presbycusis were participated in the study. PTA, speech discrimination abilities were evaluated in each subject. Diffusion tensor imaging (DTI) was applied to access the FA of the IC, the superior frontal gyrus and the Heschl's gyrus. Compare the difference between two sides of the values of FA in the three areas. Bivariate correlation analysis was performed to evaluate the effects of PTA and FA of the inferior colliculus (IC), the superior frontal gyrus and the Heschl's gyrus on speech discrimination abilities. RESULT: There were no significant differences between the left and right side of the inferior colliculus (P > 0.05). Higher FA values were recorded at the left side of the Heschl's gyrus and the superior frontal gyrus (P < 0.05). Both PTA and the FA of the superior frontal gyrus have a negative association with speech discrimination abilities (P < 0.01, P < 0.05), while the FA of the Heschl's gyrus has a positive association with speech discrimination abilities (P < 0.05). CONCLUSION: Our findings indicated that the speech discrimination abilities of the elderly is not only related to the peripheral auditory function, but also to the central auditory and cognitive function.

[Mutational analysis of candidate genes in a Chinese pedigree with dominantly inherited auditory neuropathy].

OBJECTIVE: Three genes including the OTOF, the DFNB59 and the DIAPH3 have been implicated previously in human non-syndromic auditory neuropathy. In this study, we aim to investigate whether DIAPH3 gene or the known deafness loci of 25 cloned autosomal dominant deafness (DFNA) genes contribute to the nonsyndromic hearing loss of a Chinese pedigree with dominantly inherited auditory neuropathy (AN). METHOD: Nine members of the kernal pedigree in this family were selected. Genomic DNA was isolated from the peripheral leukocytes of the subjects using the Puregene DNA Isolation Kits. Firstly, the 5'UTR of DIAPH3 gene was PCR amplified in all subjects. Then, the DNA fragments spanning the entire coding regions of DIAPH3, GJB2 and GJB3 genes, and 50 exons in other 23 cloned DFNA genes were amplified using specific primers. Each fragment was purified and analyzed by direct sequencing. The resultant sequence data were compared with the standard sequence to identify deafness-associated mutations. RESULT: PCR amplifications were successfully conducted. We failed to detect the presence either of c. --172G > A mutation in the 5'UTR that have been reported, or any other deafness-associated mutations in the whole DIAPH3 gene, by sequence analysis. We also did not find any known deafness-causing mutations among the 25 cloned DFNA genes. CONCLUSION: The DIAPH3 gene, and the known deafness loci of 25 cloned DFNA genes seem not contribute to the pathogenesis of this Chinese AN family in this study, which suggesting new gene(s) involvement.

Determination of diclazuril, toltrazuril and its two metabolites in poultry tissues and eggs by gel permeation chromatography-liquid chromatography-tandem mass spectrometry.

A new procedure has been described for the extraction of diclazuril (DIZ), toltrazuril (TOZ) and its two main metabolites toltrazuril sulphoxide (TZSO) and toltrazuril sulphone (TZS) from poultry tissues and eggs, using gel permeation chromatography (GPC). The analytes and the deuterated internal standard were extracted from the samples with ethyl acetate. The analytes were measured by LC coupled to an electrospray ionization tandem mass spectrometer operating in the negative ion mode. Excellent linear dynamic range was observed from 1 to 500 µg/L with the correlation coefficients (R(2)) better than 0.99 for all analytes. The method LOQ of the four analytes in real samples was 1.2 µg/kg for DIZ and TOZ, and 1.8 µg/kg for TZSO and TZS. These values are far lower than the maximum residue limits (MRLs) established by several control authorities. The developed method was accurate with overall recoveries in four matrices.

[Determination of 46 plasticizers in food contact polyvinyl chloride packaging materials and their migration into food simulants by gas chromatography-mass spectrometry].

A gas chromatography-mass spectrometry (GC-MS) method was developed for the determination of 46 plasticizers in food contact polyvinyl chloride (PVC) packaging materials and their migration into food simulants, i. e. water, 3% acetic acid, 10% ethanol and olive oil. Plasticizers in the PVC packaging materials, aqueous food simulants and olive oil food simulants were extracted by the dissolution-precipitation, liquid-liquid extraction and gel permeation chromatography (GPC) approaches, respectively. The extracts were analyzed by GC-MS in selective ion monitoring (SIM) mode and quantified using the external standard method. The cal-ibration curves were linear in the ranges of 0.1-2.0 mg/L with the correlation coefficients of 0.9910-0. 999 9. The limits of detection were from 0. 005 mg/kg to 0. 05 mg/kg ( S/N = 5 ). The recoveries at 3 spiked levels were 69.51%-107. 21% and the relative standard deviations (RSDs n = 6) ranged from 3.53% to 18.95%. These results show that this method is fast, sensitive and accurate for the qualitative and quantitative determination of plasticizers in food contact plastic products and 4 types of food simulants.