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Biomedical subjects

Naoto Shimura

Publications and source records attributed to Naoto Shimura.

6 recordsLinked to original sources
PubMed2006

Duration of isolation of children with influenza A treated with oseltamivir.

The duration of fervescence (24 hours in children or 30 hours in adults) was shorter in the oseltamivir group than in the placebo group. According to a Japanese law enacted before oseltamivir therapy became available, schoolchildren with influenza must be isolated 48 hours after defervescence. Our data suggest isolation should be at least 84 hours for children with influenza A treated with oseltamivir and 108 hours for preschool children.

Antibodies, Viral↗
PubMed2005

Hypocalcemia due to tubular dysfunction in a patient with holoprosencephaly.

This is the first report of a case of hypocalcemia in a female infant with holoprosencephaly. Hypocalcemia developed 60 days after birth, secondary to decreased serum 1,25-dihydroxyvitamin D, as a result of renal tubular dysfunction which may have been induced by prerenal acute renal failure, the administration of anticonvulsants, and hypothyroidism. However, there was no evidence of rickets, and her serum 25-hydroxyvitamin D value was normal. She was treated with high-dose (0.5 microg/kg) 1alpha-hydroxyvitamin D3 and calcium lactate, and her calcium and 1,25-dihydroxyvitamin D values were consequently, normalized. However, she died at 268 days after birth.

Acute Kidney Injury↗
PubMed2004

Relationship between the presence of small, dense low-density lipoprotein and plasma lipid phenotypes in Japanese children.

To clarify the relationship between the expression of atherogenic small, dense low-density lipoprotein (SDLDL) and underlying lipid metabolic abnormalities, the prevalence of SDLDL in relation to the serum lipid phenotype was analyzed in 229 children. The LDL particle size was measured using gradient gel electrophoresis, and a particle size of less than 25.5 nm was considered to represent SDLDL. The overall prevalence of SDLDL in the sample population was 8.2% (19/229; 11/117 for boys and 8/112 for girls). Hyperlipidemia phenotype IIb (elevated concentrations of both triglyceride [TG] and total cholesterol [TC]) was strongly associated with SDLDL in 83% (5/6) of the subjects. An elevated TG concentration (phenotype IV) was associated with SDLDL in 55% (10/18) of the subjects. The association between hyperlipidemia phenotype IIa (elevated TC but a normal TG concentration) and SDLDL was quite low (2%; 1/56), but SDLDL was detected in 5% (8/155) of the subjects who presented with normolipidemia. Therefore, these findings suggest that the expression of SDLDL is largely related to lipid abnormalities characterized by phenotype IIb or IV, the underlying metabolic abnormality of which is suspected to be insulin resistance; however, an additional mechanism for the formation of SDLDL that functions independently of plasma lipid abnormalities also seems to exist.

Child↗
PubMed2002

Two de novo mutations in the AR gene cause the complete androgen insensitivity syndrome in a pair of monozygotic twins.

The androgen insensitivity syndrome (AIS) is the most common cause of male undermasculinization and is typically caused by mutations in the AR gene. Affected individuals may exhibit either complete external feminization (complete AIS) or a partial phenotype (partial AIS). Here we describe monozygotic twins diagnosed with complete AIS who each possess two substitutions (C-->G at position 2930 and T-->C at position 2955, both in exon 7), leading to Phe(856)Leu and Ser(865)Pro mutations, respectively. Neither parent was found to be a carrier for these mutations, indicating that the double mutation arose de novo. Both mutations were recreated by site-directed mutagenesis and compared functionally with the wild-type receptor. The Phe(856)Leu mutation did not affect androgen binding when expressed in COS-1 cells, nor did this mutation decrease androgen-dependent trans-activation in transfected HeLa cells. However, the Ser(865)Pro mutation completely ablated androgen binding and trans-activation. In this study we demonstrate that the replacement of serine by proline at position 865 is sufficient in itself to cause complete AIS in these twins. Analyses of nuclear receptor structures suggest that this mutation is likely to perturb the conformation of helix 10/11, which plays a role in ligand binding, dimerization, and receptor activation. To our knowledge this is the first confirmed instance of AIS (complete or partial) due to an AR mutation occurring in twins. Furthermore, the phenotype was associated with two mutations that were both novel in nature.

Amino Acid Sequence↗