Galactose Information and Courses from MediaLab, Inc.
These are the MediaLab courses that cover Galactose and links to relevant pages within the course.
Learn more about laboratory continuing education for medical technologists to earn CE credit for AMT, ASCP, NCA, and state license renewal and recertification. Or get information about laboratory safety and compliance courses that deliver cost-effective OSHA safety training and continuing education to your laboratory's employees.
| When the glucose result on a urine specimen from an infant is negative on the reagent strip, it can be assumed that the specimen is negative for other reducing substances such as galactose. | View Page |
| Glucose Test The test for glucose is a double sequential enzyme reaction, utilizing the glucose-oxidase/peroxidase method. In the first reaction, glucose oxidase catalyzes the oxidation of glucose to gluconic acid and hydrogen peroxide. Then, the peroxidase catalyzes the oxidation of a chromogen by the hydrogen peroxide to form a colored product. This method does not react with lactose, fructose or galactose. Study the dipstick color chart to become familiar with the range of color changes. The urine specimen should be at room temperature for these enzyme reactions to occur properly. | View Page |
| Test for Reducing Substances Other than Glucose Urine specimens from certain pediatric patients should be tested for other reducing substances, such as galactose, when the results for glucose are negative using the routine dipstick method. The laboratory's procedure should define when additional testing is needed. | View Page |
| Other Reducing Substances Although glucose is the sugar most commonly tested for in urine, normal human urine can contain small amounts of galactose, lactose, fructose, xylose, and other pentoses. Galactosuria, an abnormal amount of galactose in the urine, occurs in infants with a congenital metabolic defect. Lactose may be found in the urine of nursing women and during late pregnancy. All of these sugars, including glucose, are reducing substances. | View Page |
| Galactose and ABO Antigen Precursor Substance Specific sugars, attached to the red cell membrane in unvarying linkage conformations, determine ABO antigenic activity. Galactose resides at the end of this specific sugar chain. This configuration constitutes the ABO antigen precursor substance. | View Page |
| Fucose Another sugar, fucose, must be attached to the galactose in a specific configuration for further antigen development to take place. This “galactose-plus-fucose” configuration has antigenic activity called “H”. | View Page |
| "B" Antigenic Activity The addition of galactose in the terminal position of the “galactose-plus-fucose” configuration give the molecule “B” antigenic activity. | View Page |
| The H gene Three separate loci (ABO, Hh, and Se) contain the genes that control the location and occurrence of the A and B antigens. Hh and Se genes are closely linked on chromosome 19. The precursor substance is acted upon by the H gene and is converted to H substance. The product of the H gene is an enzyme fucosyltransferase, responsible for attaching fucose to the terminal galactose of the precursor substance on the RBC membrane and thus forming H substance. There are only two recognized alleles at this locus: the active form, H, and an amorph, h. The H gene is a high-incidence gene. People who inherit hh are extremely rare. Since the h gene is amorphic, it does not act on the precursor substance. | View Page |
| Which specific terminal sugar causes a red cell to have A antigenic activity? | View Page |
| Which specific terminal sugar causes a red cell to have B antigenic activity? | View Page |
| What specific sugar configuration is necessary as a base for attachment of other sugars? | View Page |
| O blood cell membranes contain which the following? | View Page |