Dermal absorption of chemicals: effect of application of chemicals as a solid, aqueous paste, suspension, or in volatile vehicle.

The purpose of this study was to investigate the dermal absorption of chemicals in different physical forms when applied to female F344 rats. Chemicals were applied either as a solid, aqueous paste, suspension, or dissolved in the volatile vehicle ethanol. The chemicals investigated were [14C]-2-sec-butyl-4,6-dinitrophenol (DNBP, 4.2 mumol), 2,4,5,2',4',5'-[14C]-hexachlorobiphenyl (HCB, 2.3 mumol), and 3,4,3',4'-[14C]-tetrachlorobiphenyl (TCB, 0.5 mumol). The chemicals were applied on the clipped mid-dorsal region of the rat over a 2.54-cm2 treatment area, which was then occluded. Urine and feces were collected and assayed for radioactivity. Twenty-four hours post-application, the treated skin was washed with a mixture (1:1) of soap and water, dried, and reoccluded. The animals were sacrificed at 120 h by exsanguination under ether anesthesia. Radioactivity in the blood, skin (treated and untreated), and carcass was assayed. Dermal absorption of DNBP-derived radioactivity was approximately 50% of the recovered dose after application in the four physical forms, and the major route of excretion was via the urine. Twelve percent of the absorbed dose of DNBP was retained in the body. Dermal penetration of HCB-derived radioactivity was 5-8% of the recovered dose after application in the four forms, and the major route of excretion was via the feces. Greater than 90% of the absorbed dose of HCB-derived radioactivity was retained in the body. Dermal penetration of TCB-derived radioactivity was 6-8% of the recovered dose in the four forms, and the major route of excretion was via the feces. Approximately 21% of the absorbed dose was retained in the body at 120 h. Absorption of each chemical applied either as solid, aqueous paste, or suspension was compared to the absorption of the same chemical in ethanol. Absorption of HCB applied as a solid was significantly higher (p less than or equal to .05) as compared to HCB applied in ethanol. There were no other significantly differences in the comparisons of absorption. The data indicate that the chemicals examined in this study can penetrate the skin as readily when applied either as a solid, aqueous paste, or suspension, as when applied in the volatile vehicle ethanol.

Are combined oral contraceptives appropriate therapy for primary dysmenorrhea?

PIP: Current theories concerning the etiology of dysmenorrhea are reviewed, and the use of the combined oral contraceptive pill solely for dysmenorrhea is evaluated in light of the recent approval of antiprostaglandin agents for therapeutic use in relieving menstrual pain. Primary dysmenorrhea refers to menstrual cramping and discomfort in women free from underlying pathology and does not encompass symptoms occurring prior to the menses. There are many theories explaining the 2 types of dysmenorrhea, but none seems to offer a complete rationale. Current research appears to point toward a complex interaction of steroid hermones and prostaglandins. It is now accepted that although psychosocial factors are active in a woman's response to menstrual pain, they are not the cause. Oral contraceptives cannot be considered innocuous but have the potential for serious harm if casually prescribed and used. If a woman wants contraception concomitantly with seeking relief from severe dysmenorrhea, and if following a history and a physical she is found to be free of any pelvic pathology or contraindications for the oral contraceptive (OC), then OCs may be regarded as appropriate. There is now another choice of treatment available for dysmenorrhea -- ibuprofen -- if a woman does not need contraception or does not choose to use OC. The overall approach to care of a woman presenting with dysmenorrhea needs to be holistic. Now that there is an effective alternative in ibuprofen, continuous OC use solely for dysmenorrhea needs to be seriously questioned.^ieng

Zeolitization of tuffaceous rocks of the green river formation, wyoming.

The alkali-rich zeolites mordenite and clinoptilolite have been discovered in tuffaceous rocks of the Green River Formation, Wyoming. This occurrence strongly supports the alteration of glass to alkali-rich zeolite to analcime as the paragenetic sequence of alteration of tuffaceous rocks deposited in ancient Lake Gosiute.