Case report: pathomorphology of an experimental disseminated Aspergillus fumigatus infection in rabbits

In following a formerly successful protocol designed to produce antibodies to A. fumigatus (Fres) we observed a disseminated, lethal fungal infection in healthy, specific pathogen-free (SPF) rabbits. The pathomorphological findings included multiple miliary to avenaceous whitish nodules in the livers and kidneys, mycotic mesencephalitis, nephritis, hepatitis, myocarditis, hemorrhagic enteritis, and splenitis. The hyphae were surrounded by necrosis, which also occurred in the liver without the hyphae. Comparative gas chromatographic and metabolic investigations on this strain and some environmental A. fumigatus strains showed significant differences. The findings are discussed with particular reference to the pathogenicity of A. fumigatus.

Comparative and collaborative evaluation of standardization of antifungal susceptibility testing for filamentous fungi

The purpose of the study was to evaluate the interlaboratory agreement of broth dilution susceptibility methods for five species of conidium-forming (size range, 2 to 7 microns) filamentous fungi. The methods used included both macro- and microdilution methods that were adaptations of the proposed reference method of the National Committee for Clinical Laboratory Standards for yeasts (m27-P). The MICs of amphotericin B, fluconazole, itraconazole, miconazole, and ketoconazole were determined in six centers by both macro- and microdilution tests for 25 isolates of Aspergillus flavus, Aspergillus fumigatus, Pseudallescheria boydii, Rhizopus arrhizus, and Sporothrix schenckii. All isolates produced clearly detectable growth within 1 to 4 days at 35 degrees C in the RPMI 1640 medium. Colony counts of 0.4 x 10(6) to 3.3 x 10(6) CFU/ml (mean, 1.4 x 10(6) CFU/ml) were demonstrated in 90% of the 148 inoculum preparations. Overall, good intralaboratory agreement was demonstrated with amphotericin B, fluconazole, and ketoconazole MICs (90 to 97%). The agreement was lower with itraconazole MICs (59 to 79% median). Interlaboratory reproducibility demonstrated similar results: 90 to 100% agreement with amphotericin B, fluconazole, miconazole, and ketoconazole MICs and 59 to 91% with itraconazole MICs. Among the species tested, the MICs for S. schenckii showed the highest variability. The results of the study imply that it may be possible to develop a reference method for antifungal susceptibility testing of filamentous fungi.

Treatment with coumarin to prevent or delay recurrence of malignant melanoma

Both coumarin (1,2-benzopyrone) and warfarin (4-hydroxycoumarin) have been shown to prevent the recurrence of malignant melanoma. Their action is macrophage-dependent and the dosage is critical. In 1984 a multicentre, prospective, randomised, double-blind trial of coumarin, given as a daily 50-mg dose for 2 years after surgery in patients with high-risk melanoma, was started. the patients had lesions greater than 1.70 mm thick and TNM stage IB or stage II disease. To date there are 4 recurrences in the coumarin-treated group of 13 patients, and 10 recurrences in the placebo-treated group of 14 patients (P < 0.01). There were no toxic effects.

Melanized and non-melanized multicellular form mutants of Wangiella dermatitidis in mice: mortality and histopathology studies

One melanized (Mc3) and one non-melanized (Mc3W) multicellular form mutant of W. dermatitidis were compared with parental wild type in NYLAR mice. Each mutant grows as multicellular (muriform-like) forms in vitro at 37 degrees C and as yeasts at less than or equal to 30 degrees C. Yeast cells of all three strains were injected intravenously at concentrations of 1 x 10(4), 1 x 10(6), 1 x 10(7), 3 x 10(7) and 1 x 10(8) cells/mouse in groups of 10 mice. There was no virulence difference between wild type and Mc3, with 100% mortality obtained with each strain at greater than or equal to 1 x 10(7) cells/mouse. In contrast, Mc3W was less virulent, with mortality being obtained only at 1 x 10(8) cells/mouse. Histopathological study of brains, lungs, livers and spleens of moribund mice revealed that both Mc3 and Mc3W persisted in tissue as muriform cells, and in some cases as yeast, pseudohyphal and hyphal forms. There was no major difference between Mc3 and Mc3W in terms of histopathological response. These data support the association between melanin and virulence in W. dermatitidis and provide a model for the study of muriform cells in vivo.

Lymphocyte sub-populations following splenic irradiation in patients with chronic lymphocytic leukaemia

Four patients with chronic lymphocytic leukaemia were treated with splenic irradiation, 100 rads per week for 10 weeks. No patient had received prior therapy of any kind. All patients showed an excellent clinical response in terms of decrease in lymphocyte count in blood and bone marrow and decrease in lymph node and spleen size. B and T cell populations returned to normal in all patients as did the ratio of TG to TM cells. Two patients showed an increase in IgM levels, but the overall pattern of immunoglobulins showed no consistent change following treatment. No toxicity was incurred during treatment. We conclude that splenic irradiation is a safe and effective treatment of previously untreated patients with CLL and is associated with a return to normal of lymphocyte sub-populations. The role of the abnormal T cell population in the pathogenesis of the hypoimmunoglobulinaemia remains unclear.