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Tinnitus is a phantom sound perception affecting both auditory and limbic structures. The mechanisms of tinnitus remain unclear and it is debatable whether tinnitus alters attention to sound and the ability to inhibit repetitive sounds, a phenomenon also known as auditory gating. Here we investigate if noise exposure interferes with auditory gating and whether natural extracts of cannabis or nicotine could improve auditory pre-attentional processing in noise-exposed mice. We used 22 male C57BL/6J mice divided into noise-exposed (exposed to a 9-11 kHz narrow band noise for 1 h) and sham (no sound during noise exposure) groups. Hearing thresholds were measured using auditory brainstem responses, and tinnitus-like behavior was assessed using Gap prepulse inhibition of acoustic startle. After noise exposure, mice were implanted with multi-electrodes in the dorsal hippocampus to assess auditory event-related potentials in response to paired clicks. The results showed that mice with tinnitus-like behavior displayed auditory gating of repetitive clicks, but with larger amplitudes and longer latencies of the N40 component of the aERP waveform. The combination of cannabis extract and nicotine improved the auditory gating ratio in noise-exposed mice without permanent hearing threshold shifts. Lastly, the longer latency of the N40 component appears due to an increased sensitivity to cannabis extract in noise-exposed mice compared to sham mice. The study suggests that the altered central plasticity in tinnitus is more sensitive to the combined actions on the cholinergic and the endocannabinoid systems. Overall, the findings contribute to a better understanding of pharmacological modulation of auditory sensory gating.

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Abstract Objective: In this study, we created an animal model to demonstrate the effects of thiamine on the hearing pathways of new-borns during pregnancy and lactation by inducing a dietary thiamine deficiency in the mother. Methods: The study included 16 female Wistar albino rats. The animals were separated into four groups and provided the appropriate amounts of dietary thiamine according to their groups during pre-pregnancy, pregnancy, and lactation periods. Three pups from each mother were included in the study, and 12 pups were selected from each group. On the fortieth day after birth, the auditory pathways of 48 pups in the 4 groups were examined electro physiologically and ultra-structurally. Results: In Group N-N, morphology of hair cells stereocilia degeneration was not obtained in all turns of cochlea. In Group N-T, Inner Hair Cells (IHCs) and Outher Hair Cells (OHCs) stereocilia didn't show degeneration in all turns of cochlea but had rupture inrows of HCs stereocilia. In group T-N IHCs stereocilia less degeneration was observed in all turns of cochlea. OHC stereocilia partial loss was observed only in basal turn of cochlea. In Group T-T IHCs stereocilia was observed less degeneration and rupture in all turns of cochlea. Conclusion: Thiamine is vital for the development of cochlear hair cells during both prenatal and postnatal periods. Even partial deficiency of thiamine causes significant degeneration to the auditory pathway. Level of evidence: The level of evidence of this article is 5. This article is an experimental animal and laboratory study.

RESUMO

OBJECTIVE: In this study, we created an animal model to demonstrate the effects of thiamine on the hearing pathways of new-borns during pregnancy and lactation by inducing a dietary thiamine deficiency in the mother. METHODS: The study included 16 female Wistar albino rats. The animals were separated into four groups and provided the appropriate amounts of dietary thiamine according to their groups during pre-pregnancy, pregnancy, and lactation periods. Three pups from each mother were included in the study, and 12 pups were selected from each group. On the fortieth day after birth, the auditory pathways of 48 pups in the 4 groups were examined electro physiologically and ultra-structurally. RESULTS: In Group N-N, morphology of hair cells stereocilia degeneration was not obtained in all turns of cochlea. In Group N-T, Inner Hair Cells (IHCs) and Outher Hair Cells (OHCs) stereocilia didn't show degeneration in all turns of cochlea but had rupture inrows of HCs stereocilia. In group T-N IHCs stereocilia less degeneration was observed in all turns of cochlea. OHC stereocilia partial loss was observed only in basal turn of cochlea. In Group T-T IHCs stereocilia was observed less degeneration and rupture in all turns of cochlea. CONCLUSION: Thiamine is vital for the development of cochlear hair cells during both prenatal and postnatal periods. Even partial deficiency of thiamine causes significant degeneration to the auditory pathway. LEVEL OF EVIDENCE: The level of evidence of this article is 5. This article is an experimental animal and laboratory study.

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This study aimed to analyze the coding responses of speech sounds (syllable/da/) in children and adolescent speakers of Brazilian Portuguese with typical development and normal hearing, aged between 8 and 16 years, in order to establish normative data of speech ABR response. This normative data can be used as a reference for speech ABR responses and also to enable the diagnosis in individuals with different pathologies. The analyze for absolute latency of speech sounds, more specifically the syllable/da/, for speech-ABR in children and adolescent speakers of Brazilian Portuguese with typical development were: right ear - wave V (6,43-6,57), wave A (7,35-7,57), wave C (18,19-18,46), wave D (21,99-22,42), wave E (30,73-31,05), wave F (39,19-39,55) and wave O (47,75-48,24) and left ear - wave V (6,44-6,57), wave A (7,36-7,59), wave C (18,26-18,55), wave D (22,22 -22,50), wave E (30,58-30,97), wave F (39,05-39,35) and wave O (47,78-48,13). For the amplitude values (µv), the responses were within the following ranges: right ear - wave V (0,10-0,14), wave A (0,19-0,25), wave C (0,08-0,13), wave D (0,11-0,17), wave E (0,17-0,42), wave F (0,14-0,33) and wave O (0,11-0,31) and left ear - wave V (0,09-0,13), wave A (0,08-0,23), wave C (0,08-0,14), wave D (0,10-0,15), wave E (0,20-0,26), wave F (0,16-0,22) and wave O (0,12-0,20). For the values of complex VA (slope: µv/ms and area µv x ms) the follow values obtained were: right ear - slope (0,32-0,42) and area (0,29-0,38) and left ear - slope (0,30-0,39) and area (0,27-0,35).

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Cyanobacterial blooms can affect a wide range of aquatic organisms due to the presence of toxic compounds. However, no study so far has shown the effects of natural blooms samples on the physiological parameters related to the ecology of Daphnia. In this study we used a natural bloom sample obtained from a reservoir in Colombia to evaluate its effects on five parameters related to Daphnia's feeding behavior, swimming movements and physiology: second antennae movement (swimming), mandible movement (feeding), thoracic appendages (feeding), postabdomen movement (rejection of food particles) and heart rate (physiology). The results revealed significant changes in all parameters evaluated at two different concentrations of aqueous extracts of the bloom: second antennae movements increased significantly and there were significant reductions in mandibular movements, thoracic movements and heart rate. Although postabdominal movements showed high variability with no distinctive pattern between control and treatments, the reduction in the other parameters (such as heart rate over time) could possibly reflect an intoxication by microcystins or a behavioral response (e.g., feeding inhibition).

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OBJECTIVE: To examine the incidence of pediatric congenital hearing loss and the timing of diagnosis in a rural region of hearing healthcare disparity. STUDY DESIGN: Data from the Kentucky newborn hearing-screening program was accessed to determine the incidence of congenital hearing loss in Kentucky, both in the extremely rural region of Appalachia and non-Appalachian region of Kentucky. We also performed a retrospective review of records of children with congenital hearing loss at our institution to determine the timing of diagnostic testing. RESULTS: In Kentucky, during 2009-2011, there were 6970 newborns who failed hearing screening; the incidence of newborn hearing loss was 1.71 per 1000 births (1.28/1000 in Appalachia and 1.87/1000 in non-Appalachia); 23.8% of Appalachian newborns compared with 17.3% of non-Appalachian children failed to obtain follow-up diagnostic testing. Children from Appalachia were significantly delayed in obtaining a final diagnosis of hearing loss compared with children from non-Appalachian regions (P = .04). CONCLUSION: Congenital hearing loss in children from rural regions with hearing healthcare disparities is a common problem, and these children are at risk for a delay in the timing of diagnosis, which has the potential to limit language and social development. It is important to further assess the causative factors and develop interventions that can address this hearing healthcare disparity issue.

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OBJECTIVE: To determine whether cord serum ferritin level is associated with auditory brainstem evoked response interpeak latencies, an index of auditory neural myelination, in infants at ≥ 35 weeks gestational age (GA). STUDY DESIGN: This prospective study compared auditory neural myelination in infants with latent iron deficiency (cord serum ferritin, 11-75 ng/mL) and infants with normal iron status (cord serum ferritin, >75 ng/mL) at birth. Our inclusion criteria were infants born at ≥ 35 weeks GA who had cord blood collected soon after birth and had 1 or more of the following risk factors for poor in utero iron status: maternal diabetes mellitus, pregnancy-induced hypertension, and intrauterine growth restriction. Cord serum ferritin level was measured using the chemiluminescence immunoassay method. Auditory brainstem evoked response was measured using 80-dB normal hearing level click stimuli at a rate of 69.9/second within 48 hours after birth to evaluate interpeak latencies, a measure of nerve conduction velocity or myelination. RESULTS: Of the 45 infants studied, 12 had latent iron deficiency. On repeated-measures ANCOVA using interpeak latencies I-III, III-V, and I-V as multiple outcomes, infants with latent iron deficiency had significantly prolonged interpeak latencies (P = .01) compared with infants with normal iron status after controlling for confounders. CONCLUSION: In utero latent iron deficiency is associated with abnormal auditory neural myelination at birth in infants born at ≥ 35 weeks GA.

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TEMA: a literatura relata a ocorrência de alteração auditiva em pacientes com HIV/AIDS, podendo esta ser decorrente de comprometimentos na orelha externa, média e/ou interna. OBJETIVOS: caracterizar e comparar os resultados da avaliação audiológica e do Potencial Evocado Auditivo de Tronco Encefálico de crianças e adultos com AIDS. MÉTODOS: foram submetidos à avaliação audiológica e eletrofisiológica (Potencial Evocado Auditivo de Tronco Encefálico) 51 crianças e 22 adultos com AIDS (grupos pesquisa I e II respectivamente) e 50 crianças e 25 adultos saudáveis (grupos controle I e II respectivamente), com idade entre três e 10 anos (crianças) e entre 18 e 50 anos (adultos). RESULTADOS: nas crianças com AIDS foram mais frequentes as alterações de orelha média e nos adultos as de orelha interna, bem como maior ocorrência de resultados alterados no potencial evocado auditivo de tronco encefálico nos adultos quando comparados às crianças. CONCLUSÃO: crianças e adultos com AIDS apresentam alterações na avaliação audiológica e no potencial evocado auditivo de tronco encefálico, sugestivas de comprometimento das vias auditiva periférica e central. Os resultados enfatizam a eficácia da utilização dos testes eletrofisiológicos da audição para melhor definição do grau de lesão encefálica em pacientes com AIDS, permitindo ainda a monitorização da velocidade de evolução da doença.

BACKGROUND: according to the literature, the incidence of hearing impairment in patients with HIV / AIDS might be caused by alterations in external, middle and / or internal ear. AIM: to characterize and to compare the results of audiological assessment and Auditory Brainstem Response in children and adults with AIDS. METHOD: audiological and electrophysiological (Auditory Brainstem Response) assessment of hearing was carried out in 51 children and 22 adults with HIV/AIDS (research groups I and II, respectively) and in 50 healthy children and 25 healthy adults (control groups I and II, respectively). Participants ranged in age between 3 and 10 years (children) and between 18 and 50 years (adults). RESULTS: the most frequent observed alteration for children with AIDS was related to the middle ear whereas for adults with AIDS it was related to the internal ear. Higher occurrence of abnormal results was observed for adults with AIDS as compared to children with AIDS. CONCLUSION: children and adults with AIDS present alterations in audiological assessment and Auditory Brainstem Response. This suggests the involvement of peripheral and central auditory pathways. Findings of the present study emphasize the effectiveness of using electrophysiological hearing measures in order to better identify the brain injury level in patients with AIDS, besides allowing the monitoring of the development rate of the disease.

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The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

O desempenho de um reator anaeróbio compartimentado (RAC) foi avaliado para o tratamento da manipueira, resíduo tóxico. Um RAC dividido em quatro compartimentos de mesmo volume (volume total 4L) e operado a 35ºC foi utilizado no tratamento da manipueira. A demanda química de oxigênio (DQO) do tanque de alimentação variou de 2000 a 7000 mg L-1 e avaliou-se o tempo de residência hidráulica (TRH) mais apropriado ao melhor desempenho do reator. O RAC foi avaliado pelas análises de DQO (método colorimétrico), pH, turbidez, sólidos totais e voláteis, alcalinidade e acidez. A Análise das Componentes Principais (PCA) foi conduzida para melhor compreensão dos dados obtidos. O sistema apresentou capacidade tamponante conforme a acidez decresceu ao longo dos compartimentos ao passo que a alcalinidade e o pH aumentaram. Houve retenção do material particulado e a remoção da DQO variou de 83 a 92% para TRH de 3,5 dias.

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The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35ºC was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L(-1) and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

RESUMO

The performance of an anaerobic baffled reactor (ABR) was evaluated in the treatment of cassava wastewater, a pollutant residue. An ABR divided in four equal volume compartments (total volume 4L) and operated at 35°C was used in cassava wastewater treatment. Feed tank chemical oxygen demand (COD) was varied from 2000 to 7000 mg L-1 and it was evaluated the most appropriated hydraulic retention time (HRT) for the best performance on COD removal. The ABR was evaluated by analysis of COD (colorimetric method), pH, turbidity, total and volatile solids, alkalinity and acidity. Principal component analysis (PCA) was carried to better understand data obtained. The system showed buffering ability as acidity decreased along compartments while alkalinity and pH values were increased. There was particulate material retention and COD removal varied from 83 to 92% for HRT of 3.5 days.

O desempenho de um reator anaeróbio compartimentado (RAC) foi avaliado para o tratamento da manipueira, resíduo tóxico. Um RAC dividido em quatro compartimentos de mesmo volume (volume total 4L) e operado a 35°C foi utilizado no tratamento da manipueira. A demanda química de oxigênio (DQO) do tanque de alimentação variou de 2000 a 7000 mg L-1 e avaliou-se o tempo de residência hidráulica (TRH) mais apropriado ao melhor desempenho do reator. O RAC foi avaliado pelas análises de DQO (método colorimétrico), pH, turbidez, sólidos totais e voláteis, alcalinidade e acidez. A Análise das Componentes Principais (PCA) foi conduzida para melhor compreensão dos dados obtidos. O sistema apresentou capacidade tamponante conforme a acidez decresceu ao longo dos compartimentos ao passo que a alcalinidade e o pH aumentaram. Houve retenção do material particulado e a remoção da DQO variou de 83 a 92% para TRH de 3,5 dias.