Hearing Loss in Israeli Air Force Aviators: Natural History and Risk Factors.

OBJECTIVE: To investigate the natural history of hearing loss (HL) in Israeli military aviators and its risk factors. METHODS: Audiometric results of aviators with available audiometry at ages 30 and 40 years, and up to their last available audiometry were retrieved. HL DEFINITION: pure-tone threshold (PTT) of 30 dB or higher in at least one frequency in at least one ear, moderate-to-severe (M-S) HL as PTT of 45 dB or higher, and suspected noise-induced HL (NIHL) as HL at 3 to 6 kHz. Potential risk factors for HL were assessed by the χ(2) test and logistic regression models. RESULTS: 298 aviators were included. Rates of HL increased with age, up to 57.5% at age 50. All M-S HL at age 50 years had clues on previous examinations, but new HL was observed in all ages. Age was found as a statistically significant risk factor, but aircraft type was not. Total flying hours were found to be an independent risk factor for suspected NIHL only. Self-reported earplug use was not found to protect from HL, with methodological limitations. CONCLUSIONS: HL is prevalent in aviators. Age and total flying hours are risk factors, the latter probably only for NIHL, whereas aircraft type is not.

Cyclooxygenase-2 expression in primary and metastatic Merkel cell carcinoma.

Cyclooxygenase-2 (COX-2) is involved in the development and progression of many tumors, and its inhibition has been shown to block tumor growth. This study examined COX-2 expression in primary and metastatic Merkel cell carcinoma (MCC). Formalin-fixed paraffin-embedded tissues from 26 primary MCCs and 7 lymph node metastases were stained immunohistochemically with a monoclonal antibody directed against COX-2, and the percentage and intensity of staining were analyzed semiquantitatively. Immunopositivity for COX-2 was found in 20 primary tumors (77%), and was diffuse in 16 of them (80%). Staining intensity was strong in 5 tumors (19%), moderate in 6 (23%), and weak in 9 (35%). Five metastases (71%) showed similar staining. Prominent mitotic activity was associated with more diffuse COX-2 immunopositivity. No association was found between COX-2 expression and outcome. This study confirms that most MCCs express COX-2 and shows that COX-2 expression is related to one parameter of aggressive behavior--a high mitotic rate--but not to any others. The possibility of treating MCC with COX-2 inhibitors should be considered.