DELAYED URIC ACID ACCUMULATION IN PLASMA PROVIDES ADDITIONAL ANTI-OXIDANT PROTECTION AGAINST IRON-TRIGGERED OXIDATIVE STRESS AFTER A WINGATE TEST

Reactive oxygen species are produced during anaerobic exercise mostly by Fe ions released into plasma and endothelial/muscle xanthine oxidase activation that generates uric acid (UA) as the endpoint metabolite. Paradoxically, UA is considered a major antioxidant by virtue of being able to chelate pro-oxidative iron ions. This work aimed to evaluate the relationship between UA and plasma markers of oxidative stress following the exhaustive Wingate test. Plasma samples of 17 male undergraduate students were collected before, 5 and 60 min after maximal anaerobic effort for the measurement of total iron, haem iron, UA, ferric-reducing antioxidant activity in plasma (FRAP), and malondialdehyde (MDA, biomarker of lipoperoxidation). Iron and FRAP showed similar kinetics in plasma, demonstrating an adequate pro-/antioxidant balance immediately after exercise and during the recovery period (5–60 min). Slight variations of haem iron concentrations did not support a relevant contribution of rhabdomyolysis or haemolysis for iron overload following exercise. UA concentration did not vary immediately after exercise but rather increased 29% during the recovery period. Unaltered MDA levels were concomitantly measured. We propose that delayed UA accumulation in plasma is an auxiliary antioxidant response to post-exercise (iron-mediated) oxidative stress, and the high correlation between total UA and FRAP in plasma (R-Square = 0.636; p = 0.00582) supports this hypothesis.     

Ploidy of endothelium in high-grade astrocytomas

To determine the ploidy and proliferative activity of the endothelium in high-grade astrocytomas, the nuclear DNA content of 11 high-grade astrocytomas, including two gliosarcomas, was measured by cytophotometry. This technique allowed comparison of the endothelial population with the astrocytic population. In all cases, the endothelium was diploid, with an average of 24.6% of cells in the S + G2M phases of the cell cycle. In contrast, the astrocytic population displayed marked DNA abnormalities. The two gliosarcomas had a marked difference in proliferative activity of the endothelium with 4% and 40% of cells, respectively, in the S + G2M phases. These data indicate that the vast majority of endothelial cells compromising the vascular hypercellularity observed in high-grade astrocytomas are in the normal cell cycle whereas in many cases the malignant astrocytes are not. The nuclear DNA content of gliosarcomas appears to be similar to other high-grade astrocytomas.     

The attitudes of riparian communities to the presence of water hyacinth in the Wouri River Basin,Douala, Cameroon

Since publication of the first record of Eichhornia crassipes in Cameroon in 1997, the weed has become highly invasive in the Wouri River Basin. Between June and September 2014, a socio-economic survey using participatory and qualitative methods was undertaken in the riparian villages of the Wouri River Basin to assess the perception of respondents to the presence of water hyacinth. The survey revealed that water hyacinth was a significant threat to activities along the river, which included fishing, sand extraction and river transportation. The presence of water hyacinth mats reduced catch rates of several common fish species, river transportation by 75%, and significantly reduced the income for sand extraction. Cameroon employs manual clearing of water hyacinth; however, respondents indicated they would consider other control methods, provided they do not have any negative impacts.     

The mouthparts of female Corethrella brakeleyi and C. wirthi (Diptera: Chaoboridae)

The mouthparts of female Corethrella brakeleyi and C. wirthi were studied using light and electron microscopy. Mandibles, hypopharynx and labium are highly sclerotized and are modified for obtaining blood meals. All structures were larger in C. brakeleyi than in C. wirthi except mandibular and hypopharyngeal teeth; these were smaller and more numerous in C. brakeleyi. The labium of both species terminates in peg-like structures which are similar to those reported from several genera of mosquitoes. Sensillae on the second segment of the maxillary palps appear to be identical to those described in both biting and nonbiting male and female blackflies.     

Immune complex receptors on cell surfaces. III. Topography of macrophage receptors demonstrated by new scanning electron microscopic peroxidase marker.

Receptors for immune complexes have been localized on rabbit alveolar macrophages with scanning electron microscopy by exposing the cells first to a soluble immune complex composed of horseradish peroxidase and antibody to horseradish peroxidase, and then incubating with a benzidine-containing substrate that yields crystalline reaction product. Receptors were visualized by this means as sites of attachment of laminated slender crystals that were easily distinguished from macrophage surface structures. Receptors appeared most abundant on cytoplasmic veils and pseudopods and in the perinuclear region of macrophages minimally spread over the coverslip. Further macrophage spreading was associated with lighter receptor staining.