Objective evaluation of otolithic end organs in sudden sensorineural hearing loss patients / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To observe the function of the otolithic end organs and their input pathways in sudden sensorineural hearing loss (SSHL) patients.</p><p><b>METHODS</b>Forty cases of unilateral SSHL were enrolled as the observing group from May, 2011 to May, 2012. Thirty age- and gender-matched normal subjects were recruited as the control group. Both patients and normal subjects underwent conventional air-conducted ocular vestibular evoked myogenic potential (oVEMP) and cervical vestibular evoked myogenic potential (cVEMP) in bilateral ears. The results were compared between the affected ears, the contralateral ears and the normal controls.</p><p><b>RESULTS</b>Overall, oVEMP was elicited in 16 affected ears (40.0%), 23 contralateral ears (57.5%) and 43 normal ears (71.7%). cVEMP could be elicited in 25 affected ears (62.5%), 30 contralateral ears (75.0%) and 49 normal ears (81.7%) respectively. Significant statistical significance could be found in the oVEMP response rate between the affected ears and the normal ears (χ(2) = 9.949, P = 0.002) and in the cVEMP response rate between the affected ears and the normal ears (χ(2) = 4.582, P = 0.032). Significant statistical difference could not be found in all oVEMP and cVEMP parameters (threshold, N1 latency, P1 latency, latency interval and amplitude) among groups (P > 0.05).</p><p><b>CONCLUSIONS</b>The otolithic vestibular end organs and their input pathways could be damaged in SSHL patients. Such damages could be monitored objectively by cVEMP and oVEMP examinations.</p>

Characteristics of the air-conducted ocular evoked myogenic potential in the young normal Chinese subjects / 中华耳鼻咽喉头颈外科杂志

<p><b>OBJECTIVE</b>To identify the characteristics of the air-conducted ocular vestibular-evoked myogenic potential (oVEMP) in the young normal Chinese subjects.</p><p><b>METHODS</b>Twenty five normal subjects were recruited for conventional examinations of oVEMP. The subjects were 19 - 45 years of age [(24.3 ± 5.6) years], 12 males and 13 females. 500 Hz air-conducted tone burst was employed for examination. The threshold of oVEMP in each ear was examined; patterns of these waves were observed and the normal ranges of the oVEMP waves responded to 100 dBnHL were calculated.</p><p><b>RESULTS</b>All subjects were elicited with normal oVEMP N1-P1 waves in both ears. The response rate in these subjects was 100%. The threshold of oVEMP examination was (86.6 ± 3.6) dBnHL (x(-) ± s), latency N1 (10.1 ± 0.4) ms, latency P1 (14.7 ± 1.2) ms, interval N1-P1 (4.5 ± 1.0) ms, amplitude (7.9 ± 4.4) µV.</p><p><b>CONCLUSIONS</b>Air-conducted oVEMP is a kind of vestibular-ocular reflex respond to intensive sound generated by otolithic vestibular end organs. It is stable in the young normal subjects with minor variabilities.</p>

Construction of a recombinant eukaryotic vector of Atoh1 and its expression in 293-T cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To clone the coding sequence of Atoh1 cDNA from SD rat and construct a eukaryotic expression vector for its expression in eukaryotic cells.</p><p><b>METHODS</b>The total RNA was extracted from colonic mucosa of SD rats and the double-stranded cDNA of Atoh1 was amplified using RT-PCR. The cDNA coding sequence was then cloned into PMD-19T vector followed by sequence analysis. The digested fragment, after purification, was linked into the eukaryotic expression vector pIRES2-EGFP containing the EGFP gene and the internal ribosomes site (IRES). After identification by enzyme digestion and sequence analysis, the recombinant plasmid was transfected into 293T cells via Lipofectamine, and the expression of the target protein was detected under fluorescence microscope, using PT-PCR and Western blotting.</p><p><b>RESULTS</b>DNA sequence analysis showed that the amplified rat Atoh1 gene, with a length of 1056 bp of the coding sequence which encoded 351 amino acids, had two base mutations compared to the reference sequences in GenBank, possibly as a result of single nucleotide polymorphisms that induced nonsense mutation without affecting the amino acid sequences or the protein expression. The results of enzyme digestion and sequence analysis demonstrated that the Atoh1 gene was correctly inserted in the eukaryotic expression vector plRES2-EGFP. Fluorescence microscopy and Western blotting both confirmed successful expression of Atohl at the mRNA and protein levels in 293T cells 48 h after transfection with the recombinant plasmid.</p><p><b>CONCLUSION</b>The recombinant plasmid harboring the coding sequence of SD rat Atoh1 gene has been constructed successfully and can be expressed in the 293T cells, which provides a basis for functional study of Atoh1 gene and future researches in gene therapy for sensorineural hearing loss.</p>