Abstract: The test of the invention comprises the measuring the total amount of xylose in urine and/or its concentration in blood following oral administration of 4-O?-D-galactopyranosyl-D-xylose (4-GX) to the patient. It is a non-invasive test that is based on the direct evaluation of the global enzyme activity in the whole individual, not on measuring the metabolic consequences derived from its deficiency. It does not require specialised equipment, does not cause apparent discomfort in patients with lactase deficiency and is very reliable, thus overcoming the drawbacks of the diagnostic tests currently in use and is a statistically significantly better test in terms of its reliability; consequently it should become the reference or gold standard test for the indication of hypolactasia.

Abstract: The test of the invention comprises the measuring the total amount of xylose in urine and/or its concentration in blood following oral administration of 4-O?-D-galactopyranosyl-D-xylose (4-GX) to the patient. It is a non-invasive test that is based on the direct evaluation of the global enzyme activity in the whole individual, not on measuring the metabolic consequences derived from its deficiency. It does not require specialised equipment, does not cause apparent discomfort in patients with lactase deficiency and is very reliable, thus overcoming the drawbacks of the diagnostic tests currently in use and is a statistically significantly better test in terms of its reliability; consequently it should become the reference or gold standard test for the indication of hypolactasia.

Abstract: The test of the invention comprises the measuring the total amount of xylose in urine and/or its concentration in blood following oral administration of 4-O-?-D-galactopyranosyl-D-xylose (4-GX) to the patient. It is a non-invasive test that is based on the direct evaluation of the global enzyme activity in the whole individual, not on measuring the metabolic consequences derived from its deficiency. It does not require specialized equipment, does not cause apparent discomfort in patients with lactase deficiency and is very reliable, thus overcoming the drawbacks of the diagnostic tests currently in use and is a statistically significantly better test in terms of its reliability; consequently it should become the reference or gold standard test for the indication of hypolactasia.

Abstract: The test of the invention comprises the measuring the total amount of xylose in urine and/or its concentration in blood following oral administration of 4-O-?-D-galactopyranosyl-D-xylose (4-GX) to the patient. It is a non-invasive test that is based on the direct evaluation of the global enzyme activity in the whole individual, not on measuring the metabolic consequences derived from its deficiency. It does not require specialised equipment, does not cause apparent discomfort in patients with lactase deficiency and is very reliable, thus overcoming the drawbacks of the diagnostic tests currently in use and is a statistically significantly better test in terms of its reliability; consequently it should become the reference or gold standard test for the indication of hypolactasia.

Abstract: An enzymatic process to obtain 4-O-?-D-galactopyranosyl-D-xylose useful in compositions or solutions in the in vivo evaluation of intestinal lactose activity in humans, that comprises the steps of preparing a reaction mixture of D-xylose, a ?-D-galactopyranoside and a reaction medium that comprises water buffered to a pH between 5.0 and 9.0; adding 10 to 1,000 units of ?-D-galactosidase per gram of ?-D-galactopyranoside; subjecting the reaction mixture to a reaction or a temperature between a temperature higher than the freezing point of the reaction mixture and 45° C., for 2 to 48 hours; for the reaction by deactivation of the ?-D-galactosidase; and to isolate and crystallize the fractions that contain 4-O-?-D-galactopyranosyl-D-xylose from a crystallization mixture selected between mixtures of acetone/methanol in a ratio between 5/1 to 20/1 and mixtures of acetone/water in a ratio between 5/1 to 20/1.

Abstract: The invention relates to the use in humans of a method which is based on the use of 4-galactosyl-xylose and which involves an alternative technique to evaluate xylose in urine. The method consists of measuring the concentration of xylose in the blood following the oral administration of 4-galactosyl-xylose to the patient, the use of said method being even more suitable in the case of newborns. The invention also relates to the technology used for the in vivo evaluation of intestinal lactase activity, by way of a non-invasive test for the diagnosis of a deficiency of said enzyme, which consists of directly evaluating the overall activity of the enzyme in the individual and not in assessing the consequences of said deficiency. The inventive method does not require specialized equipment, does not cause any obvious discomfort to patients with a lactase deficiency and is extremely reliable, thereby eliminating the inconveniences of currently used diagnostic tests.

Abstract: There is disclosed the use of O-.beta.-D-galactopyranosyl-D-xyloses, particularly 2-O-.beta.-D-galactopyranosyl-D-xylose and 3-O-.beta.-D-galactopyranosyl-D-xylose, for the preparation of compositions and solutions intended to the evaluation of the intestinal lactase, which present an affinity to the substantially enchanced lactase. There is also disclosed a process for producing O-.beta.-D-galactopyranosyl-D-xyloses, comprising: reacting a D-xylose and a substrate of .beta.-D-galactopyranosyl in the presence of an enzyme .beta.-galactosidase, in an aqueous medium buffered to a pH comprised between 5.0 and 9.0 and at temperature between 4 and 37.degree. C., deactivating the .beta.-galactosidase by heating at 100.degree. C. when reaching the maximum yield of formation of disaccharides detected through thin layer chromatography, and isolating the formed disaccharides through filtration in a packed column with a thinner selected between water and water/alcohol.