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Biomedical subjects

E Naito

Publications and source records attributed to E Naito.

At least 109 records · Page 6Linked to original sources
PubMed1987

1 alpha-hydroxyvitamin D3 treatment of three patients with 1,25-dihydroxyvitamin D-receptor-defect rickets and alopecia.

Three patients with clinically different severities of vitamin D-dependent rickets, type II, with alopecia, which is 1,25-dihydroxyvitamin D-receptor-defect rickets and is particularly resistant to treatment with calciferol analogues, were treated with large doses of 1 alpha-hydroxyvitamin D3 (1 alpha-(OH)D3) and 2 g of calcium lactate. Except for the alopecia, all of the abnormalities of patients 1 and 2 were reversed by treatment with 3 micrograms/kg/d of 1 alpha-(OH)D3, and those of patient 3, who had the severest manifestations, were reversed by treatment with 6 micrograms/kg/d. The serum 24,25-dihydroxyvitamin D concentrations of the three patients were low before treatment and those of patients 1 and 2 increased during treatment. These findings suggest that in patients 1 and 2, 25-hydroxyvitamin D-24-hydroxylase was stimulated via a 1,25-dihydroxyvitamin D-receptor-mediated system by treatment with 1 alpha-(OH)D3.

24,25-Dihydroxyvitamin D 3↗
PubMed1986

Rapid diagnosis of vitamin D-dependent rickets type II by use of phytohemagglutinin-stimulated lymphocytes.

The interactions of 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] with phytohemagglutinin (PHA)-stimulated lymphocytes from normal subjects and three patients with vitamin D-dependent rickets (DDR) type II were investigated. Impaired nuclear uptake and normal cytosol binding of [3H]1,25-(OH)2D3 were observed with PHA-stimulated lymphocytes of these patients as with their cultured skin fibroblasts. Furthermore, the incorporation of [14C]thymidine into PHA-stimulated lymphocytes of the patients was not reduced by 1,25-(OH)2D3, which is known to inhibit proliferation of various cells. These findings suggest that 1,25-(OH)2D3 receptors are reduced or absent in patients with DDR type II. Thus, the capacities of cytosol binding and nuclear uptake of 1,25-(OH)2D3 in PHA-stimulated lymphocytes seem to reflect those of endo-organs such as the intestine and bone. These findings show that a test of the effect of 1,25-(OH)2D3 on thymidine incorporation into PHA-stimulated lymphocytes is useful for rapid diagnosis of DDR type II.

Calcitriol↗
PubMed1986

Involvement of thiol proteases in galactosialidosis.

The activities of Z-Phe-Arg-NMec(ZPA) hydrolase, cathepsin B and cathepsin H and the concentration of endogenous thiol protease inhibitor in fibroblasts from patients with galactosialidosis were found not to be significantly different from those in control fibroblasts. Culture for 5 days with thiol protease inhibitors such as leupeptin, E-64 or Z-Phe-Phe-CHN2 partially restored the beta-galactosidase activity of fibroblasts from patients, but did not affect the beta-galactosidase activity of fibroblasts from control subjects. However, culture with leupeptin, but not other protease inhibitors, increased the ZPA hydrolase and cathepsin B activities of fibroblasts from both patients and controls 2- to 4-fold. Sephadex G-75 chromatography showed that the activity of high molecular weight ZPA hydrolase, which was initially predominant in fibroblasts, decreased markedly during their culture with leupeptin, while the activities of lower molecular weight ZPA hydrolase and cathepsin B increased about 5-fold. These results suggest that high molecular weight ZPA hydrolase, which is presumably cathepsin J, degrades beta-galactosidase, and that the defect in galactosialidosis is impaired protection of beta-galactosidase from degradation.

Cathepsin B↗
PubMed1986

Treatment of chronic congenital lactic acidosis by oral administration of dichloroacetate.

Sodium dichloroacetate (DCA) was administered orally at a dose of 50 mg per kg body weight twice or three times per day to a newborn infant with lactic acidosis of unknown cause (patient 1) and to a 15-year-old boy with mitochondrial encephalomyopathy associated with lactic acidosis (patient 2). In patient 1, during treatment with DCA, DCA accumulated in the blood judging from the findings that the urinary excretion of DCA increased cumulatively and the blood lactate level rapidly decreased to the normal range. In patient 2, the blood DCA level gradually increased during treatment to a concentration of 250 micrograms ml-1 and the blood lactate level decreased and was maintained within the normal range. DCA was detected in the brain (25 micrograms g tissue-1) and the liver, kidney and muscle (33.8, 33.8 and 26.3 micrograms g tissue-1, respectively) obtained at autopsy of patient 1, and in the cerebrospinal fluid of patient 2 at a concentration of 125 micrograms ml-1 when the blood concentration was 250 micrograms ml-1. The lactate levels in the cerebrospinal fluid decreased from 7 and 4 mmol l-1 to 2.4 and 2.6 mmol l-1 in patients 1 and 2, respectively. Thus DCA may be useful in clinical treatment of chronic congenital lactic acidosis because it seems to cross the blood-brain barrier. However, it must be given at non-toxic doses, determined by monitoring the concentrations of lactate and DCA in the blood, because orally administered DCA tends to accumulate in tissues.

Acetates↗
PubMed1985

Activation of branched-chain alpha-ketoacid dehydrogenase complex by alpha-chloroisocaproate in normal and enzyme-deficient fibroblasts.

A method has been developed for the activation of the branched-chain alpha-ketoacid dehydrogenase complex by alpha-chloroisocaproate, an inhibitor of branched-chain alpha-ketoacid dehydrogenase kinase in human cultured skin fibroblasts. The enzyme could be activated by pretreating the cells with alpha-chloroisocaproate before they were disrupted for measurement of the activity. After this treatment, the activity was 2- to 3-fold that of untreated cells (24.8-81.4 pmol/min per mg protein). The enzyme activity in fibroblasts from a patient with maple syrup urine disease was measured by this procedure. After activation by alpha-chloroisocaproate, the activity of fibroblasts from the patient was only 10-14 pmol/min per mg protein (10% of that of controls), and was almost the same as that of the untreated cells from this patient. These results show that it is important to consider the activation state of branched-chain alpha-ketoacid dehydrogenase complex when assaying it in disrupted cells.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1985

Hereditary renal hypouricemia in children.

The renal handling of urate was investigated in four children with hereditary renal hypouricemia and in their parents. The urate/creatinine clearance ratios in the four patients were 1.02 +/- 0.28, 0.93 +/- 0.11, 1.03 +/- 0.24, and 1.46 +/- 0.26, markedly higher than those in control subjects. Except for a partial response to pyrazinamide (change in clearance ratio from 1.46 to 1.07) in one patient, pyrazinamide and benzbromarone did not affect the clearance ratios in our patients. In the parents, the urate/creatinine clearance ratios were intermediate between those of the patients and control subjects, but responses to pyrazinamide and benzbromarone were normal. These data indicate that our patients have a combined defect in renal urate reabsorption, and that one of them might be subclassified as having the hypersecretion of defect. Results also show that heterozygotes can be identified by testing their urate/creatinine clearance ratio.

Benzbromarone↗
PubMed1985

Diagnosis of partial deficiency of the pyruvate dehydrogenase complex in biopsied muscle.

We have measured the total activity of pyruvate dehydrogenase (PDH) complex, by in vitro activation with a broad specificity protein phosphatase, and the basal activity, supposed to be present in vivo, in biopsied muscles from three patients with PDH complex deficiency and 11 patients with lactic acidemia. Results showed that the total PDH complex activity must be determined in biopsied muscles for the diagnosis, because the basal activities of two of three patients with PDH complex deficiency overlapped those of two patients with lactic acidemia whose total activities were within normal range.

Adult↗
PubMed1984

Cytidine 5'-diphosphate reductase and thymidine kinase activities in phytohemagglutinin-stimulated lymphocytes of normal subjects of various ages and patients with immunodeficiency.

The activities of CDP reductase and thymidine kinase in 10(6) to 5 X 10(6) phytohemagglutinin (PHA)-stimulated lymphocytes isolated from 2 to 5 ml of peripheral blood of individual subjects were measured. The activities of CDP reductase (pmol/h/10(7) cells) and thymidine kinase (nmol/h/10(7) cells) were high in infants, 698 +/- 307 and 64.2 +/- 20.2, constant in subjects of 1-40 years old, 401 +/- 181 and 38.1 +/- 15.3, and low in persons of more than 80 years old, 121 +/- 113 and 22.3 +/- 17.8, respectively. The ratio of thymidine kinase to CDP reductase activity increased with age, indicating that dependency on the salvage pathway of DNA synthesis in lymphocytes increased with age. The activities of CDP reductase and thymidine kinase were reduced in patients with the hyperimmunoglobulin E syndrome, congenital cytomegalovirus infection, anhidrotic ectodermal dysplasia with hyperimmunoglobulin A, Bloom's syndrome, immunodeficiency with hyperimmunoglobulinemia, and Down's syndrome. The clinical symptoms of these diseases seem to be due to impaired DNA synthesis of PHA-stimulated lymphocytes, but the degrees of reduction of enzyme activities were generally greater than that of thymidine incorporation in these patients.

Adolescent↗
PubMed1984

Ribonucleotide reductase and thymidine kinase activities in various cultured cell lines derived from hematologic malignancies.

The activities of ribonucleotide reductase and thymidine kinase, and the thymidine incorporation rate were measured in 16 cultured human hematologic malignant cell lines with different cell proliferation rates. Thymidine kinase activity was significantly higher in myeloid and monocytoid cell lines than in other cell lines, but ribonucleotide reductase activity presented as CDP reductase activity was similar in the different cell lines. The ratio of thymidine kinase to CDP reductase activity was high in monocytoid cell lines. A close correlation was found between the cell proliferation rate and CDP reductase activity, but not thymidine kinase activity or the thymidine incorporation rate. The ratio of thymidine kinase to CDP reductase activity was high in slowly growing cell lines and low in rapidly growing cell lines. These results indicate that in cultured human malignant cells a high potential for proliferation may depend mainly on the de novo pyrimidine pathway of DNA biosynthesis.

Adolescent↗
PubMed1984

Interaction between quercetin and Ca2+-calmodulin complex: possible mechanism for anti-tumor-promoting action of the flavonoid.

Quercetin was found to have similar inhibitory effects on tumor promoter-induced phenomena to those of N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, a calmodulin antagonist. Moreover, quercetin was shown to interact directly with the Ca2+-calmodulin complex. These results suggest that quercetin may act as a calmodulin antagonist, and that its antagonistic effect on calmodulin may be important in its anti-tumor-promoting action in vivo.

Animals↗
PubMed1983

Effect of long-term administration of sodium benzoate to a patient with partial ornithine carbamoyl transferase deficiency.

An 8-year-old girl with partial ornithine carbamoyl transferase deficiency was treated with sodium benzoate (200 mg/kg/day) for 13 months. Before administration of sodium benzoate, her protein intake was reduced to 1.0 to 1.5 g/kg/day and her caloric intake fluctuated. Hyperammonemic attacks were frequently observed in winter. After the start of administration of sodium benzoate, the severity and frequency of these attacks decreased, although her protein intake was increased to 1.5 to 2.0 g/kg/day. No adverse effect of sodium benzoate were detected by clinical and laboratory examinations. It is concluded that long-term oral administration of sodium benzoate was effective in reducing the frequency and severity of hyperammonemic attacks in this patient. Sodium benzoate therapy in combination with dietary manipulation may improve the growth and development of these patients by allowing reduced dietary protein restriction.

Amino Acid Metabolism, Inborn Errors↗