[Evaluation of a fluorimetric for determining the activity of amylo-1,6-glucosidase in leukocytes for confirming the diagnosis of glycogen storage disease type III]. / Évaluation d'une technique fluorimétrique pour la détermination de l'activité de l'amylo-1,6-glucosidase leucocytaire pour la confirmation du diagnostic des glycogénoses de type III.

The confirmation of type III glycogen storage disease diagnosis is based on histological explorations on to live and/or muscle biopsies that induce some problems of delay and sensitivity. The purpose of this study was to evaluate a fluorimetric technique for the determination of amylo-1,6-glucosidase activity in leukocytes, in order to confirm the diagnosis of type III glycogen storage disease. The method consists in measuring the glucose released by hydrolysis of phosphorylase dextrin limit in the presence of cellular extracts, in 50 volunteers and 18 patients suspected of glycogenosis. Benefits of this technique are linearity, precision (CV = 1.68%), exactitude (CI = 0.17%), its high sensitivity (Sn = 100%) and its specificity (Sp = 96.1%). The phosphorylation of dextrin limit test allows measurement of both transferasic (α-1,4) and hydrolytic (α-1,6) enzyme activities. In conclusion, this non-invasive, and inexpensive assay, can be applied to most of the clinical biology laboratories. Comparison with radiometry and immunoblot indicate a noticeable discriminating capacity between normal subjects, patients with type I and VI glycogenosis, and patients' subgroups of type III glycogenosis.

Six-minute walk test improved forearm skin blood flow in Tunisian obese women.

The purpose of this study was to investigate whether 6-min walk test (6MWT) would improve the forearm skin blood flow (FSBF) response to acetylcholine (ACh), an endothelium-dependent vasodilator, in Tunisian women over a wide range of BMI. The FSBF was measured noninvasively using a laser Doppler flowmeter in response to local infusion of a cumulative dose of ACh, before and after the 6MWT for 102 healthy women; the results were expressed as percentage of baseline. The 6MWT was monitored and recorded. The mean response of FSBF to ACh was significantly greater before as well as after the 6MWT in lean (1,235 ± 123% vs. 1,644 ± 140%) than in overweight (630 ± 62% vs. 1,080 ± 66%) and obese subjects (402 ± 38% vs. 795 ± 40%) (P < 0.0001). Our regression analysis also revealed that the maximal FSBF response to ACh (i.e., its efficacy) was inversely correlated with BMI both before as well as after the 6MWT (r = -0.828, P < 0.0001; r = -0.859, P < 0.0001, respectively), and the efficacies of ACh in the three groups were all significantly elevated following the 6MWT (P < 0.0001). As indicated by ANOVA test, the 6MWT improved the FSBF responses of the lean, overweight, and obese subjects, by 33, 71, and 98%, respectively. We confirm that obesity induced a reduction of skin vasodilatory reserve and altered both endothelial-dependent relaxation and wall compliance. However, our new data clearly demonstrated that the 6MWT not only improved significantly the FSBF responses in the three groups of women, but the obese patients appeared to benefit more from the 6MWT than the overweight and the lean subjects.