Otoacoustic emissions as a screening test for hearing impairment in children

Transient evoked otoacoustic emissions (TEOAEs) are low amplitude sound waves produced by the healthy cochlea. They can be recorded with a microphone in the external ear. TEOAEs are abolished by hearing losses of 30 dB or more. The feasibility of using TEOAEs as a screening test for hearing loss in children was studied. TEOAE recordings were attempted in 56 children attending an audiology clinic. Recordings were possible from both ears in 52 children; of these 104 ears, 32 had hearing deficits of 30 dB or more. Hearing status was compared with the results of six TEOAE screening criteria. All criteria had a sensitivity of 1.00. Four standard TEOAE criteria yielded specificities of 0.46-0.58. Two new criteria derived from analysis of limited frequencies from the TEOAE waveform gave specificities of 0.76 and 0.82. It can be concluded that, when appropriate pass/fail criteria are employed, TEOAEs are a feasible screening test in children.     

The metabolism of the anti-tumour agent 1(1-aziridinyl)- 2,4-dinitrobenzene (CB 1837).

1-(1-Aziridinyl)-2,4-dinitrobenzene (CB 1837) is the parent member of a series of nitrophenyla-ziridines having a highly specific action against the Walker tumour in the rat. CB 1837 was much less cytotoxic in vitro than was predicted on the basis of its antitumour activity in vivo, but its activity was enhanced in the presence of liver 9000-g supernatant and cofactors, which also converted it into a metabolite, 2-amino-1-(1-aziridinyl)-4-nitrobenzene. This metabolite was more active in the in vitro test than was CB 1837.CB 1837 is extensively metabolised in vivo by the rat, and the following urinary metabolites have been identified by mass spectrometry and quantitatively determined after administration of the tritium-labelled drug: 1-(2-chloroethyl)amino-2,4-dinitrobenzene and its 2-hydroxyethylamino analogue; 2,4-dinitroaniline: 2-amino-1-(1 -aziridinyl)-4-nitrobenzene,2-amino-1-(2-chloroethyl)amino-4-nitrobenzene and their respective N(2)-acetyl derivatives; and S-[N-(2,4-dinitrophenyl)-2-aminoethyl] mercapturic acid.     

Reduced interleukin-8 response to Streptococcus pneumoniae by alveolar macrophages from adults with HIV/AIDS

BACKGROUND: HIV-infected adults are highly susceptible to pneumococcal disease. OBJECTIVE: To examine if alveolar macrophages from HIV-infected subjects exhibited a failure of cytokine production in response to Streptococcus pneumoniae in vitro. DESIGN: Case-control comparison of alveolar macrophages from 11 HIV-infected and 13 non-infected adults. METHODS: Type 1 opsonized S. pneumoniae were used to challenge the alveolar macrophages in vitro. Cell supernatant fluid was collected from unstimulated cells, and cells challenged with bacteria for 0, 6, 12 and 24 h. Cytokine production (interleukins 1beta, 6 and 8) was measured in all fluids using an enzyme-linked immunosorbent assay. RESULTS: All the cytokines tested increased over time in both HIV-infected and uninfected subjects. Interleukin-8 release was significantly lower in HIV-infected than in non-HIV-infected subjects (P = 0.02). CONCLUSION: Reduced interleukin-8 production may result in decreased neutrophil recruitment, and hence increased susceptibility to pneumococcal infection in HIV-infected subjects.