The decomposition of benzodiazepines during analysis by capillary gas chromatography/mass spectrometry.

A capillary gas chromatography column directly interfaced to a mass spectrometer was used for the analysis of sixteen benzodiazepines. The thermal stability of the drugs was found to be related to their chemical structure. Nine of the benzodiazepines were thermally unstable indicating that care should be taken in the interpretation of gas chromatographic data from this class of drugs. The unstable benzodiazepines were: ketazolam which decomposes to diazepam; N-4 oxides (chlordiazepoxide and demoxepam) which lose an oxygen radical; aromatic 7-nitro compounds (nitrazepam and clonazepam) which are partially reduced to the corresponding amine; alpha-hydroxy ketones (lorazepam and oxazepam) which decompose with the loss of water and N-methyl-alpha-hydroxy ketones (lormetazepam and temazepam) which partially decompose with the loss of a hydrogen molecule to produce the corresponding alpha, beta-diketones. Few problems were encountered in distinguishing the drugs by their mass spectra, the exceptions being ketazolam which decomposes to diazepam and demoxepam which decomposes to desmethyldiazepam. In general, good spectra were obtained from 20-50 ng of drug injected. However, for those compounds where the decompositions were not quantitative (nitrazepam, clonazepam, lormetazepam, temazepam) detection limits were poor.

Gas-liquid chromatographic retention indices of 1318 substances of toxicological interest on SE-30 or OV-1 stationary phase.

Retention indices associated with 1318 substances likely to be encountered in toxicological analyses are presented. They are listed in ascending order of retention index for identification purposes and also in alphabetical order of compound name. The 4586 values used in this collection have been extracted from 36 sources, many of which have not been previously published. In many cases, where the quoted retention index is the mean of several determinations, the reproducibility and reliability of this value may be assessed. A histogram of the 1742 values listed is provided to help in determining the usefulness of a retention index for identification purposes. The reproducibility of inter-laboratory retention index measurements for twenty compounds on both SE-30 and OV-17 are presented and show the former, on average, to give more reproducible results.

Computer-based consultation in "care" of the critically ill patient.

Despite far-reaching progress in all areas of surgery, methods of medical data analysis and communication have not kept pace with the increased rate of data acquisition. The needs to organize and communicate these data and to provide a medium for continuing education are great in critical-care areas where the amount and the diversity of data collected are enormous, and the number of surgical team members involved in patient care has grown proportionately. The computer-based Clinical Assessment, Research, and Education System (CARE) is a time-shared computer system now available on a national basis designed to provide a management and education aid for the treatment of critically ill surgical patients. An initial clinical assessment and operative note are entered by the surgeon from which an estimation of the initial fluid, blood, and electrolyte deficits are calculated. Daily doctor's progress notes, shift nurses' summaries of vital signs, clinical information, intake and output data, and drug administration, biochemical, cardiovascular, blood gas, and respiratory information are entered for each shift. From these, a metabolic balance is calculated; fluid, electrolyte, and caloric requirements are determined; cardiorespiratory parameters are computed; and various therapuetic suggestions and cautions are given to alert the physician to problems that may be arising. The surgeon-user is assisted in making the best critical-care decisions through computer-directed, interactive prompting which focuses on the most important clinical conditions and correlations and metabolic considerations and relates the important problem to the relevant literature.

Toxic substances in plants and the food habits of early man.

The widespread occurrence of toxic substances in plants must have greatly restricted their usefulness as food for primitive man. The development of cooking of plant products is suggested to have been a major evolutionary advance, making a major increase in the vegetable materials palatable to man; this technical advantage apparently occurred only in the most recent 2 percent of the anthropological record.