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Two hundred and twenty-six natural soil samples from 10 counties in Southern California were collected during the dry season and processed for members of the genus Cryptococcus. Eighteen positive samples were recovered from a total of 59 yeasts; a large number of these yeasts were found in the desert areas. The Cryptococcus isolates included 9 C. albidus, 7 C. diffluens, and 2 C. laurentii. An isolate of C. diffluens from Northern California was included in the study. Each species was associated with definite soil pH and temperature ranges, and these factors were found to be associated with distance from the west coast. C. albidus was recovered from the western areas of the survey, C. difflaens from the central and eastern area, and C. laurentii from the eastern desert only. The Northern California isolate was identified as C. diffluens and demonstrated temperature and soil pH associations similar to its Southern California counter-parts.

A method for quantitative determination of trichothecin in crude culture filtrates was presented. The method utilized an agar diffusion bioassay against Candida albicans, a colorimetric test involving a halochromatic reaction with sulfuric acid, and subsequent formation of blue color with methanol, and thin-layer chromatography of trichothecin and its dinitrophenylhydrazine derivative. A positive result in all three systems confirmed the presence of trichothecin. Quantitative results were generally in close agreement.

Trichothecin (T-cin), amphotericin B (AB), and 5-fluorocytosine (FC) were compared singly and in combination for capacities to inhibit growth of Cryptococcus neoformansin culture and to protect mice bearing infections with this yeast. The minimum inhibitory concentrations for T-cin, AB, and FC were found to be 0.5, 0.2, and 5.0 μg/ml, respectively. In vitro viability studies demonstrated a marked reduction in colony counts with the AB-FC combination and additive effects with the AB–T-cin and FC–T-cin combinations for a 3-day period. In mice infected intravenously with C. neoformans, the mean effective dose for AB was 0.38 mg/kg, and for FC it was 100 mg/kg for a 30-day treatment period. No mean effective dose could be ascertained when T-cin was tested at doses of 0.1 to 50 mg/kg. Despite this, marked beneficial effects were noted in vivo with the AB–T-cin combination, whereas additive effects and indifference were observed for AB-FC and FC–T-cin combinations, respectively. High-dose T-cin controls survived despite having received a cumulative dosage of more than twice the reported (LD50) mean lethal dose value.

The biochemistry and pharmacology of corticosteroids are reviewed as related to their clinical use, inclusive of head and neck disease. Complications and their management are discussed, as is a dosage regimen considered useful for most patients. Alternate-day corticosteroid therapy is stressed, especially in the long-term management of autoimmune and inflammatory disorders.