Metabolite collision cross section prediction without energy-minimized structures.

Matching experimental ion mobility-mass spectrometry data to computationally-generated collision cross section (CCS) values enables more confident metabolite identifications. Here, we show for the first time that accurately predicting CCS values with simple models for the largest library of metabolite cross sections is indeed possible, achieving a root mean square error of 7.0 Å2 (median error of ∼2%) using linear methods accesible to most researchers. A comparison on the performance of 2D vs. 3D molecular descriptors for the purposes of CCS prediction is also presented for the first time, enabling CCS prediction without a priori knowledge of the metabolite's energy-minimized structure.

Gynecological and reproductive issues for women in space: a review.

Women have been an integral part of United States space crews since the initial flight of Dr. Sally Ride in 1983, and a total of 40 women have been selected as U.S. astronauts. This article examines the reproductive and gynecological aspects of selecting, training, medically certifying, and flying women in space. Gynecological data from the astronaut selection cycles in 1991 to 1997 are reviewed. In addition, the reproductive implications of delaying childbearing for a career as an astronaut and the impact of new technology such as assisted reproductive techniques are examined. The reproductive outcomes of U.S. female astronauts after spaceflight are also presented. Because women have gained considerable operational experience on the Shuttle and Mir, the unique operational considerations for preflight certification, menstruation control and hygiene, contraception, and urination are discussed. Medical and surgical implications for women on long-duration missions to remote locations are still evolving, and enabling technologies for health care delivery are being developed. There has been considerable progress in the development of zero-gravity surgical techniques, including laparoscopy, thoracoscopy, and laparotomy. The concepts of prevention of illness, conversion of surgical conditions to medically treatable conditions, and surgical intervention for long-duration spaceflights are explored in detail. There currently are no operational gynecological or reproductive constraints for women that would preclude their successful participation in the exploration of our nearby solar system.

Monitoring occupational exposure to cancer chemotherapy drugs.

Reports of the health effects of handling cytotoxic drugs and compliance with guidelines for handling these agents are briefly reviewed, and studies using analytical and biological methods of detecting exposure are evaluated. There is little conclusive evidence of detrimental health effects from occupational exposure to cytotoxic drugs. Work practices have improved since the issuance of guidelines for handling these drugs, but compliance with the recommended practices is still inadequate. Of 64 reports published since 1979 on studies of workers' exposure to these drugs, 53 involved studies of changes in cellular or molecular endpoints (biological markers) and 12 described chemical analyses of drugs or their metabolites in urine (2 involved both, and 2 reported the same study). The primary biological markers used were urine mutagenicity, sister chromatid exchange, and chromosomal aberrations; other studies involved formation of micronuclei and measurements of urinary thioethers. The studies had small sample sizes, and the methods were qualitative, nonspecific, subject to many confounders, and possibly not sensitive enough to detect most occupational exposures. Since none of the currently available biological and analytical methods is sufficiently reliable or reproducible for routine monitoring of exposure in the workplace, further studies using these methods are not recommended; efforts should focus instead on wide-spread implementation of improved practices for handling cytotoxic drugs.