Extensive dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patient with AIDS

Retrospective studies have shown the occurrence of episodes of deep or superficial fungal infections in 58 to 81% of HIV/AIDS patients as a result of impairment of cell immunity. We describe a case of disseminated cutaneous dermatophytoses caused by Trichophyton mentagrophytes and Microsporum canis in a patients with AIDS. Diagnostic and therapeutic problems in relation to this unsual presentation are emphasized as well as the importance of an early mycologic diagnosis to prescribe antifungal therapy.     

Contrasting breeding systems in twoEriotheca (Bombacaceae) species of the Brazilian cerrados

The pollination biology and breeding systems ofEriotheca pubescens andE. gracilipes have been studied. These two species occur as trees in cerrado vegetation, the neotropical savannas of Central Brazil, with partially sympatric distributions. They have similar phenology and floral structure, although the flowers ofE. pubescens are larger. Both species have nectar flowers pollinated by largeAnthophoridae bees but the main pollinators of each species differ in size. The species have markedly different breeding systems: late-acting self-incompatibility inE. gracilipes and apomixis stimulated by pollination inE. pubescens.     

Reduction potential of iron in transferrin

The reduction potential of Fe3+ in transferrin was measured spectrophotometrically by equilibration with methyl viologen in the presence of sodium dithionite. For an ionic strength near 0.1 M at 25 degrees C and pH 7.3 under 0.048 atm. CO2, half of the iron is reduced at a potential near -0.40 V (vs. standard hydrogen electrode). At least one disulfide bond of the protein is partially reduced at a potential of -0.44 V, as evidenced by reaction with [14C]iodoacetate.     

Evaluation of inhibitors of eicosanoid synthesis in leukocytes: Possible pitfall of using the calcium ionophore A23187 to stimulate 5′ lipoxygenase

The effect on arachidonate metabolism of two compounds (BW755C and benoxaprofen) which have been reported to inhibit 5′ lipoxygenase in leukocytes has been evaluated in human polymorphonuclear leukocytes (PMN) stimulated with the calcium ionophore A23187 and serum-treated zymosan (STZ). The syntheses of leukotriene B₄ (LTB₄) and thromboxane B₂ (TXB₂) from endogenous substrate were determined by specific radioimmunoassays as indicators of 5′ lipoxygenase and cyclo-oxygenase activity in the PMN respectively. Benoxaprofen inhibited the synthesis of leukotriene B₄ by human PMN stimulated with the calcium ionophore A23187, but it was approximately 5 times less potent than BW755C. However, benoxaprofen (IC₅₀ 1.6 × 10⁻⁴M) was approximately 100 times less potent than BW755C (IC₅₀ 1.7 × 10⁻⁶M) at inhibiting leukotriene B₄ synthesis induced by serum-treated zymosan. Both drugs inhibited thromboxane synthesis by leukocytes stimulated with A23187 or serum-treated zymosan at similar concentrations (approximately 5 × 10⁻⁶M). The data obtained using STZ as stimulus are consistent with previous studies and indicate that benoxaprofen is a relatively selective inhibitor of cylco-oxygenase. However, this selectivity was far less apparent when A23187 was used as a stimulus to release the eicosanoids which suggests that this inhibition could be via an indirect mechanism and therefore A23187 should be used with caution as a stimulus of 5′ lipoxygenase for evaluating inhibitors of eicosanoid synthesis.     

Impaired local natural killer cell activity in human colorectal carcinomas

Summary The present study was undertaken to study natural killer (NK) cell activity in patients with colorectal cancer at peripheral and local levels. Mononuclear cells were isolated from uninvolved colorectal mucosa, tumor tissue and peripheral blood, and tested against the colon carcinoma cell line CaCo-2 and the erythroleukemia cell line K-562. Peripheral blood NK cell activity from the patients showed similar levels compared with healthy controls, whereas, mononuclear cells of tumor tissue were found to have a significantly decreased NK cell activity compared to the normal intestinal mucosa (P<0.01). No relation was found between the NK cell activity and the advancement of the disease according to the Duke's stage. Interferon- (IFN-) stimulated the NK cell activity of the mononuclear cells from blood, mucosa and tumor. However, the increase of NK cell activity after IFN- stimulation was lower in the tumor compared to the mucosa (P<0.02). The lectin, phytohaemagglutinin, increased the cytotoxicity of mononuclear cells from blood, mucosa and tumor to a similar level. These results suggest that patients with colorectal tumors exhibit a normal NK cell activity in peripheral blood and intestinal mucosa; however, a diminished NK cell activity exists at the tumor level. Although mononuclear cells isolated from the tumor have a normal response to lectin stimulation they show hyporesponsiveness to IFN- stimulation with regard to their NK cell activity.     

Measurement of nutrient spiralling during a period of continuous surface flow in a Mediterranean temporary stream (Arroyo de La Montesina, Spain)

Uptake rate of calcium, potassium, nitrate-N and phosphorus were measured in a second order Mediterranean temporary stream, in February and March 1992. This study analyzed a period of continuous surface flow between two hydrologic disturbance events (flood and drought) of an annual hydrological cycle (1991–92).The lowest values of uptake length were recorded for nitrate-N in February 92 and calcium in March 92. Nitrate had the highest uptake rate in both release performances, and potassium showed the lowest uptake rate values. The increase of calcium and nitrate uptake rate between February 92 and March 92 suggested a higher ecosystem efficiency in nutrient retention with a higher temperature and light intensity and slower water velocity, discharge and water depth. These results obtained were similar to those reported in permanent streams, indicating that in periods of continuous surface flow (without extreme hydrologic disturbance), abiotic factors can influence nutrient retention in temporary streams.