ABSTRACT
ABSTRACT Halitosis is highly prevalent in periodontitis and attributed mainly to the presence of volatile sulfur compounds (VSC), where hydrogen sulfide (H2S) is the chief culprit in the characteristic malodor of periodontitis and thus may play an active role in its pathogenesis. The aim of this study was to evaluate the effect of H2S in the acute, intermediate and chronic immuneinflammatory host response and alveolar bone loss in vivo by using an animal model of induced periodontal disease. Thirtysix rats were divided into 2 groups: test group (n = 18), rats exposed to H2S (NaHS H2S donor molecule) and control group (n = 18), rats treated with saline only (Ctrl). All animals had one of their lower second molars ligated to induce periodontal disease (PD). The sound contralateral molar was used as control (H). Each group was subdivided into 3 (n = 6), according to followup time (3h, 5 days and 14 days). The gingival tissue was used for mRNA expression analysis (IL1, IL6, RANKL, OPG and SOFAT) by realtime PCR and the mandibles were analyzed morphometrically. Data analysis showed that the ligature promoted alveolar bone loss, observed mainly at 14 days, both in the group exposed to H2S and in the Ctrl group. H2S administration did not result in additional bone loss. Gene expression showed a significant increase in IL1, IL6, RANKL and SOFAT only in the CtrlPD group (p<0.05). A significant downregulation in OPG expression was observed over time in the CtrlPD group (p<0.05). In conclusion, H2S had no effect on alveolar bone loss in the absence of a ligature. In the presence of a ligature, however, exposure to H2S had an immunoregulatory effect on the expression of proinflammatory and proresorptive cytokines.
RESUMO A halitose é altamente prevalente na periodontite e é atribuída principalmente à presença de compostos sulforosos voláteis (CSV), sendo o sulfeto de hidrogênio (H2S) o principal gás relacionado ao mau odor e que pode estar envolvido na patogênese da doença periodontal. O objetivo deste estudo foi avaliar o efeito agudo, intermediário e crônico do H2S na resposta imunoinflamatória e na perda óssea alveolar em ratos, com e sem doença periodontal induzida. Trinta e seis ratos foram divididos em 2 grupos: teste (n = 18), ratos expostos ao H2S (NaHS molécula doadora de H2S) e grupo controle (n = 18), ratos tratados apenas com solução salina (Ctrl). Todos os animais tiveram um dos seus segundos molares inferiores submetidos à colocação de uma ligadura para o desenvolvimento da doença periodontal (DP), em comparação com o dente contralateral saudável (H). Cada grupo foi subdividido em 3 (n = 6), de acordo com o tempo de eutanásia (3h, 5 dias e 14 dias). Os tecidos gengivais foram utilizados para a análise da expressão gênica (IL1, IL6, RANKL, OPG e SOFAT) por PCR em tempo real e as mandíbulas foram analisadas morfometricamente. Análise dos dados demonstrou que a ligadura promoveu perda óssea alveolar, observada principalmente aos 14 dias, tanto no grupo exposto ao H2S quanto no grupo Ctrl. A administração de H2S não resultou em perda óssea adicional. A expressão gênica demonstrou aumento significativo de IL1, IL6, RANKL e SOFAT apenas no grupo CtrlPD (p <0,05). Uma significativa regulação negativa na expressão de OPG foi observada ao longo do tempo no grupo CtrlPD (p <0,05). Podese concluir que o H2S não teve efeito adicional na perda óssea alveolar, na ausência de ligadura. Entretanto, na presença de ligadura, a exposição ao H2S teve um efeito imunorregulatório na expressão de citocinas próinflamatórias e próreabsortivas.
Subject(s)
Animals , Rats , Periodontitis/complications , Alveolar Bone Loss/etiology , Alveolar Process/drug effects , Alveolar Process/pathology , Hydrogen Sulfide/pharmacology , Disease Models, Animal , Gingiva , HalitosisABSTRACT
The purpose of this project was to determine if the hearing-impaired population reports satisfaction with their ability to converse over the telephone in both aided and unaided situations. For this study, we surveyed 104 hearing-impaired persons using a 43 item questionnaire that investigates problems that hearing-impaired people encounter when using the telephone. The questionnaire also probes the solutions that hearing-impaired people use for overcoming these problems. Of the 91 respondents who wear hearing aids, 55% use their aids while operating the telephone. However, 70% of these respondents reported that coupling the hearing aid to the telephone is problematic. Use of a telephone amplifier was reported by 73% of the sampled population. The majority of the subjects, 75%, indicated an interest in improvements in telephone communications for hearing-impaired people.
Subject(s)
Correction of Hearing Impairment , Hearing Aids , Telephone , Adolescent , Adult , Aged , Amplifiers, Electronic , Auditory Perception , Communication , Ear/physiopathology , Equipment Design , Female , Hearing Disorders/physiopathology , Humans , Male , Middle Aged , Speech Acoustics , Surveys and QuestionnairesABSTRACT
Speech intelligibility scores from 16 subjects with sensorineural hearing loss were evaluated using a digitized version of the California Consonant Test that was presented via headphones through a 300 to 3000 Hz bandpass filter to simulate the telephone band. Each subject was tested with an unprocessed signal that was frequency-equalized to compensate for the individual's hearing loss, and a signal that was equalized and compressed by the use of a compressor compression technique. Subjects were tested at three sound pressure levels above a pure-tone average threshold for frequencies 1 and 2 kHz. Two digital signal processing techniques designed to compensate for high-frequency hearing loss were examined: frequency domain processing and time domain processing. Frequency domain involved modification of the short-term spectrum obtained through a fast Fourier transform, whereas time domain processing involved passing the signal through a bank of finite impulse response filters. Both techniques showed significant intelligibility improvements (15-30%). In a second experiment, 16 additional subjects with high-frequency hearing loss compared an amplified telephone signal to three processed signals: (1) 6 dB per octave emphasis; (2) a signal frequency equalized for their hearing loss; and (3) a signal that was equalized for their hearing loss and was compressed according to their uncomfortable loudness levels. Most subjects preferred the signal with the 6 dB per octave emphasis.
