Adherence of Candida albicans to bladder mucosa: development and application of a tissue explant assay.

In order to study the interactions between Candida species and uroepithelial tissue, a tissue explant assay was developed using bladder mucosa harvested from New Zealand white rabbits. Blastoconidia of Candida albicans, Candida tropicalis and Candida glabrata attached to the uroepithelial tissue in similar quantities. However, there was significantly more adherence to the uroepithelium by pre-germinated C. albicans compared with C. albicans blastoconidia. Furthermore, the amount of uroepithelial tissue injury was directly related to the length of exposure of the tissue to Candida. Thus, this tissue explant assay may provide a useful method for investigating properties related to fungal adherence to transitional uroepithelium and organism-mediated tissue injury.

Increased adherence of fluconazole-resistant isolates of Candida species to explanted esophageal mucosa.

The adherence of fluconazole-resistant and fluconazole-susceptible isolates of Candida albicans to explanted rabbit esophageal mucosa was examined in vivo. Among six Candida albicans isolates collected from HIV-infected patients, three fluconazole-resistant (MIC > 64 microg/ml) isolates attached more avidly than three fluconazole-susceptible strains (MIC < or = 0.5 microg/ml) to esophageal mucosa (P < or = 0.05). When three strains each of six different Candida spp. were compared, the more inherently fluconazole-resistant isolates adhered more avidly in the following order: Candida glabrata>Candida krusei>Candida albicans fluconazole-sensitive>Candida tropicalis>Candida parapsilosis. Nonetheless, fluconazole-resistant Candida albicans demonstrated the greatest degree of adherence in comparison to all fluconazole-susceptible Candida albicans (P<0.001) and to all Candida spp. tested (P<0.001). Thus, the refractoriness of esophageal candidiasis in patients infected with fluconazole-resistant isolates may be related to both in vitro drug resistance and increased mucosal adherence.

Response of human polymorphonuclear leukocytes and monocytes to Trichosporon beigelii: host defense against an emerging opportunistic pathogen.

To further understand human host defenses against Trichosporon beigelii, functional responses were investigated of polymorphonuclear leukocytes (PMNL) and elutriated human monocytes (EHM) to this opportunistic fungal pathogen. There was significantly less PMNL phagocytosis (P < .001) and killing (P < .001) of T. beigelii isolates than of Candida albicans. However, levels of superoxide anions generated by PMNL in response to T. beigelii and C. albicans were comparable. Pretreatment of PMNL with granulocyte colony-stimulating factor or interferon-gamma (IFN-gamma) did not significantly enhance fungicidal activity. Killing of T. beigelii by EHM also was significantly impaired compared with killing of C. albicans (P < .001). However, pretreatment of EHM with macrophage colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, or IFN-gamma all resulted in enhanced fungicidal activity. Thus, phagocytosis and killing of T. beigelii by PMNL and EHM are significantly less efficient than that of C. albicans. However, monocytes may be more important in the control of Trichosporon species than previously shown.

The menstrual cycle from a bio-behavioral approach: a comparison of oral contraceptive and non-contraceptive users.

The purpose of the present study was to clarify the effects of the menstrual cycle on: (1) accuracy and simple reaction time in a problem-solving situation; (2) academic performance; (3) identify corresponding cyclic changes in a set of psychophysiological measures during rest/test conditions; and (4) to compare oral contraceptive with non-oral contraceptive users. Eight volunteer females, 4 normally cyclic and 4 oral contraceptive users, reported once weekly throughout two menstrual cycles during which changes in blood pressure, heart rate, skin temperature, finger pulse amplitude, and verbal reaction time were monitored. Differences in verbal reaction time were found between oral contraceptive users and non-users over phases of the cycle, the users being significantly slower during menstrual and premenstrual phases. It was also observed that all subjects reacted slower in the menstrual and ovulatory phases during cycle one, although no differences were found during cycle two. Skin temperature changes between groups occurred during the postovulatory phase of cycle two, the control group having shown a much greater increase than oral contraceptive users. These results indicated a suppressive influence of oral contraceptives which appeared to affect cognitive rather than motor responses, and that these effects were residual when no pills were taken menstrually and premenstrually. Also indicated was the finding that although a 28-day cycle of menstrual events exists, periodicity of these events may be reflected in a much larger cycle non-currently defined.