| Autor: |
Schneider, Jerry A, Bradley, Kathryn H, Seegmiller, J Edwin |
| Zdroj: |
Pediatric Research; November 1968, Vol. 2 Issue: 6 p441-450, 10p |
| Abstrakt: |
Extract: The transport and intracellular fate of cysteine-35S was studied in leukocytes from nine children with cystinosis and nine control subjects of similar age in an attempt to explain the presence of 80 times the normal quantity of free cystine in cystinotic leukocytes. Two differences were observed: the cystinotic cells took up nearly twice as much cysteine-35S as did control cells. Subsequently, almost 40 percent of the 35S was found as the oxidized form, cystine-35S in cystinotic leukocytes, compared with only 2 percent in control leukocytes. Comparison of intracellular and extracellular concentrations of cysteine-35S at steady state showed no differences between normal and cystinotic leukocytes. Both cell types incorporated 30 percent of the intracellular 35S into glutathione and showed the same time course of 35S efflux.Speculation: The increased uptake of cysteine-35S shown by cystinotic leukocytes could be taken as valid conventional evidence for a primary defect in the transport of cysteine in cystinosis. The prompt appearance of the extra 35S transported as intracellular cystine-35S suggests, however, that this rapid conversion may be the primary defect and that the increased uptake of cysteine-35S is but a compensatory mechanism for maintaining the physiological concentration of intracellular cysteine. |
| Databáze: |
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