ABSTRACT
Numerous epidemiology studies have failed to adequately demonstrate an increased risk of lung cancer due to occupational exposure to carbon black (CB). CB is not carcinogenic to mice (oral, skin or inhalation), hamsters (inhalation or intratracheal), guinea pigs (inhalation), rabbits (skin or inhalation), primates (skin or inhalation) or rats (oral). Only studies conducted by inhalation and intratracheal administration in rats have shown significant increases in benign and malignant lung tumors and lesions described as benign cystic keratinizing squamous-cell (KSC) tumors. CB-induced lung tumor formation, including KSC lesions, occurs only in rats. An expert panel reviewing KSC lesions (induced in rats by TiO2 or p-aramid) concluded that KSC lesions are not seen in humans. Lung tumors in humans are primarily located in the bronchial airways, whereas in the rat they occur in the parenchyma and are alveolar in origin. This species-specific response (tumor formation and KSC lesions) by the rat to CB, not seen in any other laboratory species and which has not been reported in humans, strongly suggests that the results of the rat inhalation bioassay should not be considered directly relevant when assessing human risk. Therefore, CB should not be classified as carcinogenic to humans based on the rodent bioassay data.
Subject(s)
Carbon/classification , Carbon/toxicity , Carcinogens/classification , Carcinogens/toxicity , International Agencies , Lung Neoplasms/chemically induced , Lung Neoplasms/epidemiology , Anatomy, Comparative , Animals , Biological Assay , Humans , Inhalation Exposure , International Agencies/classification , Mutagenicity Tests , Occupational Exposure , Predictive Value of Tests , Risk Assessment , Rodentia , Species SpecificityABSTRACT
Twenty-two patients with tinea versicolor (pityriasis versicolor) were treated with a single 400 mg dose of ketoconazole and evaluated one month later. All patients were found to be clinically cured when examined with Wood's light and microscopic techniques approximately one month after the initial dose. Hypopigmented macules persisted for several months in most patients. Prophylaxis with single monthly doses of 400 mg of ketoconazole has resulted in one recurrence to date, with follow-up for four to fifteen months (mean of 8.2 months) in twenty patients. No side effects from ketoconazole were reported by any of the patients.
Subject(s)
Ketoconazole/therapeutic use , Tinea Versicolor/drug therapy , Adolescent , Adult , Female , Humans , Ketoconazole/administration & dosage , Male , Middle Aged , Tinea Versicolor/prevention & controlSubject(s)
Affect , Behavior, Animal , Olfactory Nerve/physiology , Aggression , Animals , Columbidae , Female , Humans , Male , Ophthalmic Nerve/physiology , Restraint, PhysicalABSTRACT
Transectioned olfactory nerves in birds can reestablish structural and functional connections with the olfactory bulbs in comparatively short time spans, thereby hampering long-range studies of avian olfaction and behavior. Accordingly, techniques are described that are suitable for impeding the reconstitution of the olfactory nerve after its transection in the pigeon. These involve the use of inexpensive and easily obtainable materials including cotton pellets, glass beads, and polyethylene tubing.
