Melamine-related urinary stones in 195 infants and young children: clinical features within 2 years of follow-up.

OBJECTIVE: To summarize the clinical features and follow-up, the effects of melamine-tainted milk powder (MMP) consumption on kidney and body growth in children who suffered from melamine-related urinary stones (MUS) 2 years earlier were checked. MEASUREMENTS: Body height and weight, kidney and bladder morphology monitored by ultrasound, urinalysis and renal function were recorded. Plain abdominal radiography was performed for differential diagnosis. The first follow-up was carried out at 15 months and the second 2 years later for patients who showed any abnormality at the first follow-up. Two hundred age- and gender-matched cohorts were included. RESULTS: All cases received conservative treatment in hospital. Fifteen months of follow-up was successfully carried out in 167 cases. 91 children had residual MUS at the time of discharge, 58 MUS disappeared completely, 25 dissolved partially, 1 increased in size, and 7 did not change. At 2 years of follow-up, the residual stones all disappeared except for 1 case; the patient who showed a delayed development with regard to height caught up at 24 months of follow-up. CONCLUSIONS: Conservative treatment shows a high effectiveness in cases with residual MUS. Consumption of MMP with timely treatment did not demonstrate an evident impact on kidney and bladder although body height is slightly affected in a few cases.

Chemical modification identifies two populations of glycerophospholipid flippase in rat liver ER.

Transbilayer flipping of glycerophospholipids in the endoplasmic reticulum (ER) is a key feature of membrane biogenesis. Flipping appears to be an ATP-independent, bidirectional process facilitated by specific proteins or flippases. Although a phospholipid flippase has yet to be identified, evidence supporting the existence of dedicated flippases was recently obtained through biochemical reconstitution studies showing that certain chromatographically resolved fractions of detergent-solubilized ER proteins were enriched in flippase activity, whereas others were inactive. We now extend these studies by describing two convenient assays of flippase activity utilizing fluorescent phospholipid analogues as transport reporters. We use these assays to show that (i) proteoliposomes generated from a flippase-enriched Triton X-100 extract of ER can flip analogues of phosphatidylcholine, phosphatidylethanolamine, and phosphatidylserine; (ii) flipping of all three phospholipids is likely due to the same flippase(s) rather than distinct, phospholipid-specific transport proteins; (iii) functional flippases represent approximately 1% (w/w) of ER membrane proteins in the Triton extract; and (iv) glycerophospholipid flippase activity in the ER can be attributed to two functionally distinct proteins (or classes of proteins) defined by their sensitivity to the cysteine and histidine modification reagents N-ethylmaleimide and diethylpyrocarbonate, respectively. Analyses of the N-ethylmaleimide-sensitive class of flippase activity revealed that the functionally critical sulfhydryl group in the flippase protein is buried in a hydrophobic environment in the membrane but becomes reactive on extraction of the protein into Triton X-100. This observation holds considerable promise for future attempts to isolate the flippase via an affinity approach.