Toxicological response of Sprague Dawley rats from inhalation exposure to perfluorooctane sulfonyl fluoride (POSF).

Perfluorooctane sulfonyl fluoride (POSF) was a volatile starting material in the production of perfluorooctane sulfonate (PFOS), a stable surfactant that has been extensively studied due to its ubiquitous environmental distribution and slow clearance in humans. Because the inhalation toxicity of POSF on repeated exposure has not been previously reported, the current study evaluated the inhalation toxicity of POSF at 30, 100, and 300ppm (v/v) in rats for up to 13 weeks with a four-week recovery period. The extent of PFOS formation was also measured because POSF hydrolyzed to form PFOS. In addition, detailed urinalysis and examination of the urinary bladder were included to determine if factors associated with the development of bladder cancer were present. Exposure to POSF at 300ppm was associated with reduction in body weight-gain, necrosis of laryngeal cartilage, increased lung and bronchi weight with septal thickening, and changes in alveolar macrophages. The microscopic observations in larynx and lung are consistent with likely hydrolysis of POSF to form hydrogen fluoride (HF). Exposure to POSF at 100 and 300ppm was associated with increased relative liver weight, hepatocellular hypertrophy (except for females exposed to 100ppm POSF), and lowering of serum cholesterol (male only). After 13 weeks of exposure to 30, 100, or 300ppm POSF, serum PFOS concentration approximated 7, 35, or 100µg/mL, respectively. Approximately 0.1% of inhaled POSF was converted to PFOS. No changes indicative of bladder effects were observed in these rats exposed to POSF at any dose.

Laryngeal necrosis after combined chemotherapy and radiation therapy.

Post-radiation necrosis of the larynx is a major complication after irradiation and has become rare. Recently, combined chemotherapy and radiation therapy has been introduced for head and neck tumours. The authors report a case of laryngeal necrosis after combination therapy for a patient with cervical lymph node metastases of nasopharyngeal carcinoma and review the literature on late laryngeal necrosis. Although radiation-induced laryngeal necrosis has become a rare complication, the combination of chemotherapy and radiation therapy may increase its incidence. We should always consider it as a possible late complication and treat it appropriately.

Histologic and histochemical study of effects of anabolic steroids on the female larynx.

The larynges of 30 unmated, mature female albino mice were examined histologically and histochemically after injecting them with 19-nandrolone phenylpropionate. Permanent irreversible changes, in the form of parakeratosis and squamous metaplasia of the epithelium, and hypertrophy of the muscle fibers, were observed together with persistence of increased alkaline phosphatase enzyme intensity in the endothelium of capillaries and increased activity of nonspecific esterase in the muscles. Similar changes may be responsible for the alteration in the human female's voice after prolonged treatment with anabolic steroids.

The effects of lignocaine spray on the laryngeal mucosa of the cat.

The laryngeal mucosa of cats which had been treated with a lignocaine aerosol spray prior to endotracheal intubation was examined histologically. A degree of oedema and cell damage was apparent. When one side of the larynx was sprayed before intubation and the other side protected in the same cat, cellular damage was greater on the side which received the lignocaine spray. In no cat were the changes considered severe enough to constitute a post-anaesthetic hazard.