RT Journal Article SR Electronic T1 Studies on retinitis pigmentosa in man. I. Taurine and blood platelets. JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 771 OP 775 DO 10.1136/bjo.66.12.771 VO 66 IS 12 A1 M J Voaden A1 A A Hussain A1 I P Chan YR 1982 UL http://bjo.bmj.com/content/66/12/771.abstract AB Platelets from patients with various genetically determined forms of photoreceptor dystrophy and with the clinical manifestations of retinitis pigmentosa (RP) have been studied. Variations in protein content have been observed, with less than normal in multiplex RP (probably autosomal recessive inheritance) and more in platelets from patients with autosomal dominant RP. This may reflect variation in platelet size or in surface adsorption of plasma proteins. Several patients presented with thrombocytopenia, the mean platelet count for X-linked hemizygote patients, as a group, being significantly lower than normal. Accumulation of 3H-taurine has been studied in platelets incubated in Ca2+-free Krebs bicarbonate medium containing 1.0 microM or 60.0 microM taurine, and in autologous plasma. Although, in general, platelets from patients with RP showed normal taurine uptake, the capacity of the higher affinity carrier was increased in patients with X-linked hemizygote and multiplex disease. In contrast, plasma from patients with X-linked hemizygote RP reduced the platelet tissue to medium ratio, established for 3H-taurine uptake, by 20%. More studies are needed to ascertain whether this represents a reduced taurine uptake or is caused by an increased concentration of taurine in the plasma.