Akihito Ueta

Chronic zinc toxicity in an infant who received zinc therapy for atopic dermatitis

UNLABELLED In Japan and many other industrialized countries, zinc is readily available as a nutritional supplement, for cosmetic purposes and for the treatment of atopic dermatitis. The potential risks associated with its use are not, however, fully recognized. As a reciprocal relationship exists between copper and zinc, excessive zinc can produce hypocupraemia, which can cause anaemia and neutropenia. We report on a male infant who presented with anaemia and neutropenia and showed signs of developmental delay after dietary restriction for food allergy and eating difficulties and zinc therapy administered for the treatment of atopic dermatitis at a dose nine times the daily dietary allowance for his age group. After 1 mo of zinc withdrawal, copper and ceruloplasmin concentrations had increased, and the blood cell count had improved, activity was increasing but verbal development remained limited. As development improved after withdrawal of zinc, we cannot rule out a relation between developmental delay and hyperzincaemia and/or hypocupraemia. CONCLUSION Caution must be exercised in administering zinc to children during their neurological development.

A Japanese case with inosine triphosphate pyrophosphohydrolase deficiency attributable to an enzymatic defect in white blood cells

Summary: Inosine triphosphate pyrophosphohydrolase (ITPase) deficiency is characterized by abnormal accumulation of inosine triphosphate. We describe the first Japanese case with ITPase deficiency and demonstrate that the deficiency of ITPase activity is not only found in erythrocytes but also in white blood cells.

Allopurinol challenge tests performed before and after living-related donor liver transplantation in citrullinaemia

Summary: We performed allopurinol challenge tests to evaluate the metabolic state of a citrullinaemic patient who received a living-relative donor liver transplant. Before transplantation, large amounts of orotic acid and orotidine were excreted during the challenge test. Following transplantation, excretion of these compounds in response to allopurinol was normalised. The challenge test was a safe and useful method to evaluate the metabolic state of the patient.

Novel mutations in the cytochrome P450 2C19 gene: a pitfall of the PCR-RFLP method for identifying a common mutation

AbstractCYP2C19 is a clinically important enzyme involved in the metabolism of therapeutic drugs such as (S)-mephenytoin, omeprazole, proguanil, and diazepam. Individuals can be characterized as either extensive metabolizers (EM) or poor metabolizers (PM) on the basis of CYP2C19 enzyme activity. The PM phenotype occurs in 2-5% of Caucasian populations, but at higher frequencies (18-23%) in Asians. CYP2C19*2 and CYP2C19*3, which are single-nucleotide polymorphisms of CYP2C19, are the main cause of PM phenotyping in homozygotes or compound heterozygotes. We report two novel mutations in the CYP2C19 gene identified by direct sequencing and subcloning procedures. One of these mutations was considered to be CYP2C19*3 by polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP). This result suggests that mutations classed as CYP2C19*3 might include other mutations. Further studies are needed to clarify the relationship between these novel mutations and enzyme activity.

Urinary uracil in female patients with ornithine transcarbamylase deficiency

Abstract Background : Female patients with ornithine transcarbamylase deficiency (OTCD) show a wide range of clinical severity, from asymptomatic to lethal hyperammonemia. It is important to establish a simple method to distinguish symptomatic from asymptomatic patients.

Chronic zinc toxicity in an infant who received zinc therapy for atopic dermatitis: Clinical observations

In Japan and many other industrialized countries, zinc is readily available as a nutritional supplement, for cosmetic purposes and for the treatment of atopic dermatitis. The potential risks associated with its use are not, however, fully recognized. As a reciprocal relationship exists between copper and zinc, excessive zinc can produce hypocupraemia, which can cause anaemia and neutropenia. We report on a male infant who presented with anaemia and neutropenia and showed signs of developmental delay after dietary restriction for food allergy and eating difficulties and zinc therapy administered for the treatment of atopic dermatitis at a dose nine times the daily dietary allowance for his age group. After 1 mo of zinc withdrawal, copper and ceruloplasmin concentrations had increased, and the blood cell count had improved, activity was increasing but verbal development remained limited. As development improved after withdrawal of zinc, we cannot rule out a relation between developmental delay and hyperzincaemia and/or hypocupraemia.