Shift of serum osteocalcin components between cord blood and blood at day 5 of life.

Vitamin K deficiency is a relatively common condition in neonates. However, the role of vitamin K in neonatal bone metabolism remains to be determined. Osteocalcin (OC) is the most abundant noncollagenous protein in bone, and is regulated to be gamma-carboxylated by vitamin K. In this study, we measured gamma-carboxylated osteocalcin (Gla-OC) and non- or undercarboxylated osteocalcin (Glu-OC) separately, and examined the effects of vitamin K on osteocalcin metabolism. Eighteen full-term healthy neonates were enrolled in this study. In the cord and d-5 blood samples, the OC levels were determined by three different methods to examine the intact OC by immunoradiometric assay (IRMA), Gla-OC, and Glu-OC. Serum vitamin K fractions, hepaplastin test, and type 1 procollagen carboxyl extension peptide were also determined. Urine samples were also collected from the first voiding and on d 5 to determine urinary pyridinoline, deoxypyridinoline, and gamma-carboxylated glutamic acid. Serum levels of phylloquinone (PK) and menaquinone (MK)-4 increased on d 5 following vitamin K administration and increased intake in breast milk and/or formula. The OC levels determined by IRMA did not change between cord and d-5 blood samples, but the Gla-OC level increased remarkably and Glu-OC reduced to a negligible level. OC in cord blood is mainly Glu-OC, and Glu-OC is replaced with Gla-OC within 5 d of life after vitamin K supplement. The IRMA assay fails to distinguish Gla-OC from Glu-OC and caution is needed to estimate bone turnover with this method in the perinatal period.

Preventive effect of TAK-751S on complications of hemorrhagic colitis (results of clinical study of TAK-751S).

BACKGROUND: The effective therapy for hemolytic uremic syndrome and encephalopathy caused by enterohemorrhagic Escherichia coli have not been established. Great attention has been drawn to the results of the clinical study of TAK-751S, performed in Canada. In Japan, a nationwide clinical study of TAK-751S had been performed since 1997 to investigate the preventive effect on the onset of HUS and the safety. METHODS: TAK-751S was administered in daily doses of 500 mg/kg for one week to 128 pediatric patients with colitis who were suspected of enterohemorrhagic Escherichia coli (EHEC) infection. RESULTS: 1. TAK-751S was confirmed to absorb Shiga toxin (Stx) existing inside the human intestine and to excrete Stx out of the body. 2. The incidence of HUS is 5.9% (4/68) and a tendency to inhibit the onset of HUS was observed as compared with the historical control. The complications of central neuropathy such as encephalopathy were observed in 3 of these patients with HUS. 3. Mild "sweating" and "nausea" were observed. There were 13 mild non-specific abnormalities of laboratory test values in 8 patients. CONCLUSIONS: From these results, it was clarified that TAK-751S absorbed and removed free Stx in the intestinal tract of pediatric patients with EHEC infection. The test drug could not inhibit the onset of HUS completely, but since HUS occurred within 48 hours after the start of administration in 3 of the 4 patients with onset of HUS, TAK-751S is a safe drug for pediatric patients with EHEC infection in which the preventive effect on HUS and encephalopathy are expected when it can be given from an early stage of the diseases. Furthermore, these results suggest that importance of rapid diagnosis of HUS.

Characterization of renal chloride channel (CLCN5) mutations in Dent's disease.

Dent's disease is an X-linked renal tubular disorder characterized by low molecular weight proteinuria, hypercalciuria, nephrocalcinosis, nephrolithiasis, and renal failure. The disease is caused by mutations in a renal chloride channel gene, CLCN5, which encodes a 746 amino acid protein (CLC-5), with 12 to 13 transmembrane domains. In this study, an additional six unrelated patients with Dent's disease were identified and investigated for CLCN5 mutations by DNA sequence analysis of the 11 coding exons of CLCN5. This revealed six mutations: four frameshift deletions involving codons 392, 394, 658, and 728, one nonsense mutation (Tyr617Stop), and an A to T transversion at codon 601 that would result in either a missense mutation (Asp601Val) or creation of a novel donor splice site. These mutations were confirmed by restriction endonuclease or sequence-specific oligonucleotide hybridization analysis and were not common polymorphisms. The frameshift deletions and nonsense mutation predict truncated and inactivated CLC-5. The effects of the putative missense Asp601Val mutant CLC-5 were assessed by heterologous expression in Xenopus oocytes, and this revealed a chloride conductance that was similar to that observed for wild-type CLC-5. However, an analysis of the mutant CLCN5 transcripts revealed utilization of the novel donor splice site, resulting in a truncated CLC-5. Thus, all of the six mutations are likely to result in truncated CLC-5 and a loss of function, and these findings expand the spectrum of CLCN5 mutations associated with Dent's disease.