A new implantable middle ear hearing device for mixed hearing loss: A feasibility study in human temporal bones

HYPOTHESIS

To assess the feasibility of a new, active middle ear device in temporal bones (TB).

BACKGROUND

This device is designed for patients with mixed hearing loss subsequent to chronic middle ear infection, surgery, or trauma. This Bell-Vibroplasty is built from a VIBRANT MED-EL Vibrant Soundbridge and a Kurz Bell titanium partial ossicular replacement prosthesis.

METHODS

In three fresh TBs, healthy and reconstructed middle ears were analyzed by means of laser Doppler interferometry. The sound transmission properties of a partial ossicular replacement prosthesis and a passive and an active Bell-Vibroplasty were compared with healthy middle ear function.

RESULTS

The measurements provided reliable results with small standard deviations and good signal-to-noise ratios. The performance levels of the partial ossicular replacement prosthesis and of the passive Bell-Vibroplasty were comparable with that of healthy middle ear function. The activated Bell-Vibroplasty provided linear function and a flat frequency response within the measured frequency range (500 Hz-8 kHz), with peak deviations of less than 10 dB. The maximum output of the Bell-Vibroplasty was equivalent to 125-dB sound pressure level.

CONCLUSION

Bell-Vibroplasty is feasible in TBs. Bell-Vibroplasty performance in TBs is sufficient to allow for a clinical trial as a next step.

Effect of HIV-1 infection on tuberculosis and fertility in a large workforce in Kinshasa, Democratic Republic of the Congo

To determine the effect of an HIV counseling service on the incidence of HIV and tuberculosis infection and on the fertility rate in a large workforce cohort of adult men and women from Kinshasa, Democratic Republic of Congo (formerly Zaire), we conducted a 2-year prospective longitudinal cohort study, two large Kinshasa businesses (a commercial bank and a textile factory). We determined baseline HIV-1 seroprevalence, HIV-1 and tuberculosis mortality/morbidity, and fertility rates during 24 months of follow-up on 8866 employees and 6411 wives of male employees. The baseline HIV-1 seroprevalence was 2.8% in male employees (n = 6657), 8.4% in female employees (n = 417), and 2.4% in the wives of male employees (n = 4692). The HIV-1 seroincidence per 100 person-years of follow-up in these three groups was 0.9, 0.5 and 0.8, respectively. The incidence of tuberculosis was 2.4/100 person years in persistently seropositive individuals compared with a 0.38 rate in persistently seronegative individuals (p < 0.01). The annual fertility rate in persistently seronegative women was 250.0/1000 women compared with a rate of 140/1000 in persistently seropositive women (p < 0.001). Forty-eight (44%) of 105 male employees and 17 (26%) of 60 wives of male workers who died during follow-up were HIV-1 seropositive. HIV infection was responsible for nearly one half of all deaths in this large workforce. Tuberculosis incidence was six times higher in HIV-1-infected compared with uninfected individuals. Counseling of HIV-infected women and their husbands appeared to be effective as their cumulative fertility rate was 44% lower than the rate in similarly aged uninfected women.

Expression of multiple forms of brain cytochrome P450

Multiple forms of cytochrome P450 (P450) in brain tissue have been demonstrated to be expressible in brain tissue using polymerase chain reaction (PCR) techniques, Northern blotting, hydroxylation activity assessment and cloning approaches. The antidepressant drug imipramine is metabolized by brain microsomes to multiple products by pathways inhibitable by quinidine, 7,8-benzoflavone, and ketoconazole, well-known inhibitors of P450-catalyzed reactions. Moreover, PCR studies revealed that a number of P450s are expressible in brain tissue and in glioma C6 cells. Quantitative PCR studies further demonstrated the response of many of these forms to induction in agreement with hydroxylation activity results.

Heterosexual transmission of HIV-1 among employees and their spouses at two large businesses in Zaire

To better understand the reasons why up to 80% of all HIV-1 infections in Zaire, but less than 5% in North America and Europe, are acquired through heterosexual transmission, and to assess the impact of HIV-1 infection on a large urban African workforce, we enrolled 7068 male employees, 416 female employees and 4548 female spouses of employees at two large Kinshasa businesses (a textile factory and a commercial bank) in a prospective study of HIV-1 infection. The HIV-1 seroprevalence rate was higher in male employees (5.8%) and their spouses (5.7%) at the bank than among male employees (2.8%) and their spouses (3.3%) at the textile factory. At both businesses HIV-1 seroprevalence was higher among employees in managerial positions (5.0%) than among workers in lower-level positions (3.0%; P less than 0.0001). In a multivariate analysis of male employees, receipt of a transfusion, a history of genital ulcer disease, working at the bank, urethritis, or being divorced or separated were independently associated with HIV-1 infection. During 1987 and 1988, AIDS was the most common cause of death among recently employed workers, accounting for 20 and 24% of all deaths at the textile factory and the commercial bank, respectively. The HIV-1 seroprevalence rate was higher among female workers (7.7%) than among the spouses of male workers (3.9%; P = 0.001). In multivariate analysis of the wives of workers, having an HIV-1-seropositive spouse, receipt of a blood transfusion, or a history of genital ulcer disease were independently associated with HIV-1 infection.(ABSTRACT TRUNCATED AT 250 WORDS)