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This article documents the case of a patient with severe renal failure immediately after having been given high-dose methotrexate; the patient was effectively treated with repeated hemodialysis, charcoal hemoperfusion, leucovorin, and thymidine. The methotrexate plasma concentration was reduced from 390 mumol/L to 7 mumol/L as a result of 24.5 hours of hemodialysis along with 39.5 hours of hemoperfusion. Although a rebound in the plasma methotrexate concentration occurred the first three times that hemodialysis and/or hemoperfusion was stopped, reinstitution of the procedure was always effective in further lowering methotrexate concentrations. The patient was subsequently managed with leucovorin and thymidine rescue. Simultaneous measurements before and after the hemodialysis-hemoperfusion apparatus and before and after the hemoperfusion device alone revealed a percent decrease in the concentration of d-leucovorin of 36% and 79%; 1-leucovorin, 82% and 75%; 5-methyltetrahydrofolate, 52% and 64%; methotrexate, 73% and 37%; and 7-hydroxymethotrexate, 21% and 24%, respectively. Gastrointestinal and hematologic toxicities were completely prevented, and serum creatinine normalized within 24 days.

Spacecraft exploration of Mars has shown that the essential resources necessary for life support are present on the martian surface. The key life-support compounds O2, N2, and H2O are available on Mars. The soil could be used as radiation shielding and could provide many useful industrial and construction materials. Compounds with high chemical energy, such as rocket fuels, can be manufactured in-situ on Mars. Solar power, and possibly wind power, are available and practical on Mars. Preliminary engineering studies indicate that fairly autonomous processes can be designed to extract and stockpile Martian consumables. The ability to utilize these materials in support of a human exploration effort allows missions that are more robust and economical than would otherwise be possible.

A simulation is carried out of the evolution of an optically thick dust cloud in the earth's atmosphere, and calculations are made of the effects that such a dust cloud would have on the amount of visible light reaching the surface and the temperature at the earth's surface. It is found that large quantities of dust remain in the atmosphere for periods of only three to six months. This duration is fixed by the physical processes of coagulation; these cause the rapid formation of micron-sized particles and sedimentation that quickly removes the particles from the atmosphere. The duration of the event is found to be nearly independent of the initial altitude, initial particle size, initial mass, atmospheric vertical diffusive mixing rate, and rainout rate. It depends to a slight extent on the particle density and the probability that colliding particles stick together to form a larger particle. In addition, the duration is limited by the rate at which the debris spreads from the initial impact site. A doubling code is used to calculate the visible radiative transfer in the dust clouds. It is found that light levels are too low for vision for one to six months and too low for photosynthesis for two months to one year.

Principal science goals for exploration of Mars are to establish the chemical, isotopic, and physical state of Martian material, the nature of major surface-forming processes and their time scales, and the past and present biological potential of the planet. Many of those goals can only be met by detailed analyses of atmospheric gases and carefully selected samples of fresh rocks, weathered rocks, soils, sediments, and ices. The high-fidelity mineral separations, complex chemical treatments, and ultrasensitive instrument systems required for key measurements, as well as the need to adapt analytical strategies to unanticipated results, point to Earth-based laboratory analyses on returned Martian samples as the best means for meeting the stated objectives.

The 7 October, 1981 occultation of SAO 187124 by 88 Thisbe was observed at twelve sites. The occultation observations, together with information about the asteroid's light curve, gives a mean diameter for Thisbe of 232 + or - 10 km. This value is 10 percent larger than the previously published radiometric diameter of Thisbe.