Background: Chitotriosidase (CT) is a surrogate plasma marker for Gaucher disease. The enzyme is released by storage cells and is on average thousand fold elevated in serum of Gaucher patients. Plasma CT level is measured with the substrate 4-methylumbelliferyl (4MU)-chitotriose or 4MU-chitobiose. Given the limitations associated with the use of these substrates, a novel substrate, 4MU-deoxychitobiose, has recently been conceived.Methods: Chitotriosidase activity was measured with all three substrates in serum samples from 91 type 1 Gaucher patients. Glucocerebrosidase and chitotriosidase genotypes were determined as well as disease parameters.Results: Chitotriosidase activity when measured with 4MU-deoxychitobiose gave higher values and was proportional to enzyme concentration over a much larger range as compared to the other two substrates. Patients that were carrier for the common CT mutation showed on average half the activity of those with wild type CT genotype. Plasma CT levels correlated best with combined liver and spleen volume: r=0.53 (p < 0.001).Conclusions: The use of 4MU-deoxychitobiose as substrate renders a substantial improved CT activity assay and may further facilitate accurate laboratory monitoring of Gaucher patients. (c) 2007 Published by Elsevier B.V.

Background. Accumulating clinical experience with ozone administration for conditions associated with ischemia has been encouraging. The aim of our study was to determine the effect of ozone on reperfusion injury in an isolated rat heart model. Methods: Isolated rat hearts were perfused with modified Krebs-Henseleit buffer solution via ascending aorta cannulation. After 15 minutes, perfusion was stopped and global ischemia was maintained for 30 minutes, following which perfusion was restarted, and continued for 40 minutes. Baseline hemodynamic measurements (heart rate, left ventricular developed pressure (LVDP), dP/dt, and coronary flow) were taken prior to ischemia, and every 10 minutes after reperfusion was started. Eleven hearts were treated with ozone during reperfusion and eight hearts served as controls. In the treatment group, after 5 minutes of reperfusion, ozone was administered in distilled water via a side arm for 5 minutes. Results: Preischemic baseline hemodynamic measurements and coronary flow were similar in the two groups. Hearts treated with ozone during reperfusion exhibited better recovery than did controls. Mean ( SE) percent recovery for treatment and control groups, respectively, was: LVDP 69 2% vs 51 6% (p = 0.04); dP/dt 68.9 +/- 13.3% vs 53.7 +/- 20.4% (p = 0.05); and LVDPxHR 61.4 +/- 3.3% vs 44.4 +/- 3.5% (p = 0.02). Conclusion: In the isolated rat heart model, treatment with ozone during reperfusion enables better recovery than in controls. Although the mechanism by which ozone exerts its beneficial effect is not identified, it is possibly due to reduction in reperfusion injury.