The high frequency of GJB2 gene mutation c.313_326del14 suggests its possible origin in ancestors of Lithuanian population.

BACKGROUND: Congenital hearing loss (CHL) is diagnosed in 1 - 2 newborns in 1000, genetic factors contribute to two thirds of CHL cases in industrialised countries. Mutations of the GJB2 gene located in the DFNB1 locus (13q11-12) are a major cause of CHL worldwide. The aim of this cross-sectional study was to assess the contribution of the DFNB1 locus containing the GJB2 and GJB6 genes in the development of early onset hearing loss in the affected group of participants, to determine the population-specific mutational profile and DFNB1-related HL burden in Lithuanian population. METHODS: Clinical data were obtained from a collection of 158 affected participants (146 unrelated probands) with early onset non-syndromic HL. GJB2 and GJB6 gene sequencing and GJB6 gene deletion testing were performed. The data of GJB2 and GJB6 gene sequencing in 98 participants in group of self-reported healthy Lithuanian inhabitants were analysed. Statistic summary, homogeneity tests, and logistic regression analysis were used for the assessment of genotype-phenotype correlation. RESULTS: Our findings show 57.5% of affected participants with two pathogenic GJB2 gene mutations identified. The most prevalent GJB2 mutations were c.35delG, p. (Gly12Valfs*2) (rs80338939) and c.313_326del14, p. (Lys105Glyfs*5) (rs111033253) with allele frequencies 64.7% and 28.3% respectively. GJB6 gene mutations were not identified in the affected group of participants. The statistical analysis revealed significant differences between GJB2(-) and GJB2(+) groups in disease severity (p = 0.001), and family history (p = 0.01). The probability of identification of GJB2 mutations in patients with various HL characteristics was estimated. The carrier rate of GJB2 gene mutations - 7.1% (~1 in 14) was identified in the group of healthy participants and a high frequency of GJB2-related hearing loss was estimated in our population. DISCUSSION: The results show a very high proportion of GJB2-positive individuals in the research group affected with sensorineural HL. The allele frequency of c.35delG mutation (64.7 %) is consistent with many previously published studies in groups of affected individuals of Caucasian populations. The high frequency of the c.313_326del14 (28.3 % of pathogenic alleles) mutation in affected group of participants was an unexpected finding in our study suggesting not only a high frequency of carriers of this mutation in our population but also its possible origin in Lithuanian ancestors. The high frequency of carriers of the c.313_326del14 mutation in the entire Lithuanian population is supported by it being identified twice in the ethnic Lithuanian group of healthy participants (a frequency 2.0 % of carriers in the study group). CONCLUSION: Analysis of the allele frequency of GJB2 gene mutations revealed a high proportion of c. 313_326del14 (rs111033253) mutations in the GJB2-positive group suggesting its possible origin in Lithuanian forebears. The high frequency of carriers of GJB2 gene mutations in the group of healthy participants corresponds to the substantial frequency of GJB2-associated HL in Lithuania. The observations of the study indicate the significant contribution of GJB2 gene mutations to the pathogenesis of the disorder in the Lithuanian population and will contribute to introducing principles to predict the characteristics of the disease in patients.

A randomized cross-over study to evaluate the swallow-enhancing and taste-masking properties of a novel coating for oral tablets.

OBJECTIVE: To explore the swallowing-enhancing and taste-masking effects of MedCoat, a new disposable device used to apply a coating to tablets just before oral administration. SETTING: Kaunas Medical University Hospital in Lithuania. METHOD: The study was performed as a randomized cross-over study. In total 41 subjects (20 male and 21 female) were enrolled in the study. Subjects were healthy volunteers who at least sometimes experience difficulties swallowing tablets. Subjects were asked to swallow placebo tablets uncoated and coated with MedCoat in a randomized order, and indicate their preferences. Subjects were also asked to evaluate the taste-masking properties of MedCoat. RESULTS: Of the 41 subjects, 40 (97.6%) found it less difficult to swallow non-flavoured placebo tablets coated with MedCoat compared to identical uncoated tablets. Forty subjects (97.6%) found it less difficult to swallow divided non-flavoured placebo tablets coated with MedCoat compared to identical uncoated divided tablets. All 41 subjects (100.0%) found it less difficult to swallow bitter flavoured placebo tablets coated with MedCoat compared to identical uncoated tablets. All 41 (100.0%) of the subjects stated that MedCoat completely masked the bitter taste of a bitter flavoured tablet. CONCLUSION: The study showed that MedCoat made tablets easier to swallow for people with difficulties swallowing tablets and that it masked the taste of bitter tasting tablets. MedCoat could therefore be a valuable tool to aid the oral taking of tablets for patients who have difficulties swallowing tablets.

Effects of UMTS cellular phones on human hearing: results of the European project EMFnEAR.

Abstract The European project EMFnEAR was undertaken to assess potential changes in human auditory function after a short-term exposure to radiofrequency (RF) radiation produced by UMTS (Universal Mobile Telecommunication System) mobile phones. Participants were healthy young adults with no hearing or ear disorders. Auditory function was assessed immediately before and after exposure to radiofrequency radiation, and only the exposed ear was tested. Tests for the assessment of auditory function were hearing threshold level (HTL), distortion product otoacoustic emissions (DPOAE), contralateral suppression of transiently evoked otoacoustic emission (CAS effect on TEOAE), and auditory evoked potentials (AEP). The exposure consisted of speech at a typical conversational level delivered via an earphone to one ear, plus genuine or sham RF-radiation exposure produced by a commercial phone controlled by a personal computer. Results from 134 participants did not show any consistent pattern of effects on the auditory system after a 20-min UMTS exposure at the maximum output of the phone with 69 mW/kg SAR in the cochlea region in a double blind comparison of genuine and sham exposure. An isolated effect on the hearing threshold at high frequencies was identified, but this was statistically nonsignificant after correction for multiple comparisons. It is concluded that UMTS short-term exposure at the maximum output of consumer mobile phones does not cause measurable immediate effects on the human auditory system.

Search for clinical and neurophysiological prognostic patterns of brain coma outcomes in children.

OBJECTIVE: The aim of the study was to evaluate the possible predictive values of clinical examinations combined with the recordings of electroencephalography and brainstem auditory-evoked potentials in traumatic coma of pediatric patients. MATERIAL AND METHODS: A total of 43 children in coma with severe acute head trauma were included in the study. They were investigated and treated in pediatric intensive care unit using standard evaluation and treatment protocol. Evaluation of coma was performed using Glasgow Coma Scale. Electroencephalography for 35 patients and brainstem auditory-evoked potentials for 24 patients were recorded. RESULTS: Glasgow coma scale statistic pool median was equal to 4 points as measured in presence of brain edema, meanwhile it was 6 as measured in absence of edema. In case of supratentorial damage, median duration of consciousness recovery was 10 days. In absence of above-mentioned supratentorial damage, recovery of the consciousness was earlier - median was 5 days. Determined duration of artificial lung ventilation was statistically significantly shorter for those who had edema (P=0.048). In 20 patients (57% of all cases), constant or alternating slow wave activity was observed during the first electroencephalographic recording. In other cases, "alpha coma" or low amplitude of arrhythmic activity and local slowing activity corresponding to brain damage seen on computerized tomography were recorded. For 24 patients, brainstem auditory-evoked potentials were recorded. In 9 cases, they were abnormal; in these cases, the consciousness of the patients recovered after 44 days or did not recover. CONCLUSIONS: Glasgow coma scale results alone may have limited prognostic value in absence of other objective neurophysiologic investigation data concerning the coma outcome in children. Prognosis may be worse if pathological brainstem auditory-evoked potentials correlate with pathological dynamic changes in electroencephalography and brain lesions, diagnosed during computerized tomography scan.

Assessment of potential effects of the electromagnetic fields of mobile phones on hearing.

BACKGROUND: Mobile phones have become indispensable as communication tools; however, to date there is only a limited knowledge about interaction between electromagnetic fields (EMF) emitted by mobile phones and auditory function. The aim of the study was to assess potential changes in hearing function as a consequence of exposure to low-intensity EMF's produced by mobile phones at frequencies of 900 and 1800 MHz. METHODS: The within-subject study was performed on thirty volunteers (age 18-30 years) with normal hearing to assess possible acute effect of EMF. Participants attended two sessions: genuine and sham exposure of EMF. Hearing threshold levels (HTL) on pure tone audiometry (PTA) and transient evoked otoacoustic emissions (TEOAE's) were recorded before and immediately after 10 min of genuine and/or sham exposure of mobile phone EMF. The administration of genuine or sham exposure was double blind and counterbalanced in order. RESULTS: Statistical analysis revealed no significant differences in the mean HTLs of PTA and mean shifts of TEOAE's before and after genuine and/or sham mobile phone EMF 10 min exposure. The data collected showed that average TEOAE levels (averaged across a frequency range) changed less than 2.5 dB between pre- and post-, genuine and sham exposure. The greatest individual change was 10 dB, with a decrease in level from pre- to post- real exposure. CONCLUSION: It could be concluded that a 10-min close exposure of EMFs emitted from a mobile phone had no immediate after-effect on measurements of HTL of PTA and TEOAEs in young human subjects and no measurable hearing deterioration was detected in our study.