Impact of historical mining assessed in soils by kinetic extraction and lead isotopic ratios.

The aim of this study is to estimate the long-term behaviour of trace metals, in two soils differently impacted by past mining. Topsoils from two 1 km(2) zones in the forested Morvan massif (France) were sampled to assess the spatial distribution of Cd, Cu, Pb and Zn. The first zone had been contaminated by historical mining. As expected, it exhibits higher trace-metal levels and greater spatial heterogeneity than the second non-contaminated zone, supposed to represent the local background. One soil profile from each zone was investigated in detail to estimate metal behaviour, and hence, bioavailability. Kinetic extractions were performed using EDTA on three samples: the A horizon from both soil profiles and the B horizon from the contaminated soil. For all three samples, kinetic extractions can be modelled by two first-order reactions. Similar kinetic behaviour was observed for all metals, but more metal was extracted from the contaminated A horizon than from the B horizon. More surprising is the general predominance of the residual fraction over the "labile" and "less labile" pools. Past anthropogenic inputs may have percolated over time through the soil profiles because of acidic pH conditions. Stable organo-metallic complexes may also have been formed over time, reducing metal availability. These processes are not mutually exclusive. After kinetic extraction, the lead isotopic compositions of the samples exhibited different signatures, related to contamination history and intrinsic soil parameters. However, no variation in lead signature was observed during the extraction experiment, demonstrating that the "labile" and "less labile" lead pools do not differ in terms of origin. Even if trace metals resulting from past mining and metallurgy persist in soils long after these activities have ceased, kinetic extractions suggest that metals, at least for these particular forest soils, do not represent a threat for biota.

Short communication: effect of kefir grains on proteolysis of major milk proteins.

The effect of kefir grains on the proteolysis of major milk proteins in milk kefir and in a culture of kefir grains in pasteurized cheese whey was followed by reverse phase-HPLC analysis. The reduction of kappa-, alpha-, and beta-caseins (CN), alpha-lactalbumin (alpha-LA), and beta-lactoglobulin (beta-LG) contents during 48 and 90 h of incubation of pasteurized milk (100mL) and respective cheese whey with kefir grains (6 and 12 g) at 20 degrees C was monitored. Significant proteolysis of alpha-LA and kappa-, alpha-, and beta-caseins was observed. The effect of kefir amount (6 and 12 g/100mL) was significant for alpha-LA and alpha- and beta-CN. alpha-Lactalbumin and beta-CN were more easily hydrolyzed than alpha-CN. No significant reduction was observed with respect to beta-LG concentration for 6 and 12 g of kefir in 100mL of milk over 48 h, indicating that no significant proteolysis was carried out. Similar results were observed when the experiment was conducted over 90 h. Regarding the cheese whey kefir samples, similar behavior was observed for the proteolysis of alpha-LA and beta-LG: alpha-LA was hydrolyzed between 60 and 90% after 12h (for 6 and 12 g of kefir) and no significant beta-LG proteolysis occurred. The proteolytic activity of lactic acid bacteria and yeasts in kefir community was evaluated. Kefir milk prepared under normal conditions contained peptides from proteolysis of alpha-LA and kappa-, alpha-, and beta-caseins. Hydrolysis is dependent on the kefir:milk ratio and incubation time. beta-Lactoglobulin is not hydrolyzed even when higher hydrolysis time is used. Kefir grains are not appropriate as adjunct cultures to increase beta-LG digestibility in whey-based or whey-containing foods.

Tolerance and efficacy of argon plasma coagulation for controlling bleeding in patients with typical and atypical manifestations of watermelon stomach.

BACKGROUND AND STUDY AIMS: Watermelon stomach is a well-known cause of gastrointestinal bleeding and anemia. This study investigated the efficacy of and patient tolerance for argon plasma coagulation (APC) in this condition. PATIENTS AND METHODS: The reports of 21 patients with watermelon stomach who were treated using APC from February 1998 to August 2001 were reviewed. The efficacy of APC was evaluated on the basis of the patients' symptoms, transfusion requirements, and hemoglobin levels. RESULTS: Fifty-nine APC sessions were carried out (mean 2.81 sessions per patient, range one to five). Depending on the bleeding outcome and lesion intensity, repeat treatments were carried out with a mean delay of 1.8 months (range 2 days - 6 months). The mean follow-up period after the last session was 14.9 months (1 - 60.6 months). All of the patients required repeated blood transfusions before APC, compared with only two patients after treatment. One of these two patients died of uncontrolled bleeding despite APC. The mean hemoglobin level was 80.9 g/l before treatment, compared with 103.2 g/l after treatment. Three patients had recurrent bleeding 4.4 - 31.7 months (mean 13.8 months) after the last session and required a further session of APC, which controlled bleeding in all cases. Complications encountered consisted of two cases of hematemesis and one of sepsis. CONCLUSIONS: APC was effective in controlling bleeding due to watermelon stomach in the great majority of patients, with a low complication rate.