Using tissue cysteine to predict the trophic transfer of methylmercury and selenium in lake food webs.

The biomagnification of toxic methylmercury (MeHg) and selenium (Se) through aquatic food webs using nitrogen stable isotopes (δN) varies among ecosystems but underlying mechanisms are yet unexplained. Given the strong links between MeHg and thiol-containing amino acids and proteins containing selenocysteine, our hypothesis was that cysteine content is a better predictor of MeHg and Se transfer through lake food webs than δN. Food web samples were collected from six lakes in Kejimkujik National Park, Nova Scotia, Canada, and the regression slopes of log MeHg or Se versus protein-bound cysteine or bulk δN were compared.

[Invasive squamous cell carcinoma: about 2 cases].

Conjunctival tumors are common in tropical areas, where exposure to ultraviolet radiation is high and almost permanent. Malignant tumors are quite rare and the most represented is conjunctival squamous cell carcinoma. We report two cases of invasive squamous cell carcinoma of the conjunctiva received in the ophthalmology department of the Sominé Dolo hospital in Mopti, Mali.

[Treatment of congenital ptosis in a low-income country: polypropylene frontalis sling at the African Institute of Tropical Ophthalmology].

Introduction: Treatment of congenital ptosis is exclusively surgical; the frontalis sling method is most appropriate when the ptosis is severe, with no upper eyelid levator function. This surgery typically utilizes various materials (autologous fascia lata, silicone, nylon, or polypropylene bands, etc.).

Tissue content of thiol-containing amino acids predicts methylmercury in aquatic invertebrates.

Aquatic invertebrates vary in methylmercury (MeHg) levels among systems which has been attributed, in part, to environmental conditions, but may also be linked to differences in their biochemical composition. As MeHg is known to bind to thiol-containing amino acids such as cysteine in proteins of fish, our objective was to determine if these amino acids explain MeHg variability among aquatic invertebrate taxa. Benthic macroinvertebrates from diverse functional feeding groups and bulk zooplankton were collected from six acidic lakes in Kejimkujik National Park, Nova Scotia, Canada, and analyzed for MeHg, cysteine (as cysteic acid), methionine (as methionine sulfone), and nitrogen (relative trophic level, δN) and carbon (carbon source, δC) isotopes.

[Evaluation of the quality of life of adult patients treated in low vision at the CHU-IOTA].

Introduction: Visual impairment is a handicap defined as any alteration of visual function responsible for a partial or total limitation of the activities of daily living (OMS, 2004). The objective of this study is to assess quality of life in patients before and after management of low vision.

Patients And Methods: This was a mono-centric, transverse, analytical study over a period of 6 months.