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Biomedical subjects

R Minami

Publications and source records attributed to R Minami.

At least 127 records · Page 7Linked to original sources
PubMed1982

alpha-D-mannosidase in the liver and brain from patients with I-cell disease.

The properties of alpha-D-mannosidase in the liver and brain from patients with I-cell disease were investigated, using 4-methylumbelliferyl-alpha-D-mannopyranoside as a substrate. A combination of chromatographies on DEAE-cellulose, concanavalin A-Sepharose and Sephacryl S-300 showed that intermediate alpha-D-mannosidase was present in the liver and brain from I-cell disease as well as control liver and brain, although an abnormal distribution of intermediate and acidic alpha-D-mannosidases occurred in the tissues from I-cell disease. These results suggested that a defect of intermediate alpha-D-mannosidase is unlikely to be the primary defect responsible for I-cell disease.

Brain↗
PubMed1982

Acidic glycosaminoglycans and gangliosides in the brains from four patients with genetic mucopolysaccharidosis.

Acidic glycosaminoglycans (GAGs) and gangliosides were analyzed in the brains from control fetuses, fetal Hurler syndrome, control children and three patients affected by genetic mucopolysaccharidosis (Hurler, Hunter and Morquio syndromes). GAGs contents in the brains from patients with Hurler and Hunter syndromes were approximately 1.5-3.0-fold greater as compared with those controls, and most of the GAGs were much more degraded than those from controls. Dermatan sulfate (DS), which was not identified in the control brains, comprised about 20--40% of the total GAGs. On the other hand, GAGs content and molecular weight distribution in the brain from the patient affected by Morquio syndrome were similar to those in the control brains. GAGs content in the brain from fetal Hurler syndrome was also 2.0-fold greater and DS, which was not detected in the control fetal brains, comprised 1.6% of the total GAGs. However, the molecular weight distribution of the GAGs was similar to those of the control fetal brains. The total amount of the brain gangliosides in all patients assayed here was similar to those in the control brains. However, a greater amount of GM1- and Gm2-gangliosides was observed in the brains from patients with Hurler and Hunter syndromes.

Adolescent↗
PubMed1981

Prenatal diagnosis of Hurler's syndrome--biochemical studies on the affected fetus.

A prenatal diagnosis of Hurler's syndrome was made in a pregnancy at risk in a family with two affected children. The fetus was diagnosed as having Hurler's syndrome on the basis of a deficiency of alpha-L-iduronidase in the cultured amniotic cells. The glycosaminoglycans (GAG) content in the supernatant of the amniotic fluid was increased about 1.5 fold compared with that in the control, and increases of heparan sulfate and dermatan sulfate were observed on electrophoresis. The diagnosis could be confirmed by the deficiencies of alpha-L-iduronidase in the liver and brain from the affected fetus. GAG content in the liver from the affected fetus was increased approximately 10 fold as compared with that in the control fetal liver, and most of the GAG were degraded. The GAG content was observed to be increased two fold in the brain, and dermatan sulfate, which was not detected in normal fetal brain, was identified. beta-Galactosidase activities in the affected liver and brain were decreased to 30-50% of the control, and an altered hexosaminidase A was also observed in the liver.

Amniotic Fluid↗
PubMed1981

Uridine diphosphate galactose 4-epimerase deficiency.

A case of uridine diphosphate galactose (UDP-Gal) 4-epimerase deficiency was discovered by mass screening of newborn infants. UDP-Gal 4-epimerase activity of red blood cells from the patient was found to be remarkably low, i.e., 7.5% of the level in normal controls at comparable ages. The parents showed intermediate values between those of the patient and controls. The enzyme activity in a specimen of liver tissue obtained from the patient by needle biopsy revealed a normal value. Subsequently, two other families with the condition were found by mass screening and these individuals were found to be heterozygotes.

Carbohydrate Epimerases↗
PubMed1981

Vitamin D dependent rickets: decreased sensitivity to 1,25-dihydroxyvitamin D.

A patient with vitamin D dependent rickets with decreased sensitivity to 1,25-Dihydroxyvitamin D was observed. She suffered from bone pain of two years duration beginning at 12 years of age and was found to be suffering from hypocalcemia, secondary hyperparathyroidism and osteomalacia. Laboratory findings revealed normal serum 25-hydroxyvitamin D (27 ng/ml) and markedly elevated serum 1,25-dihydroxy-vitamin D (131.9 pg/ml). The hypocalcemia was refractory in spite of administration of 25,000 units of vitamin D2, but therapy with high doses of oral la-hydroxyvitamin D3 resulted in significant elevation of the serum calcium level. The clinical findings and course of the patient's disease were quite different from those of other patients with vitamin D dependent rickets reported by other authors.

Adolescent↗
PubMed1981

Hexosaminidase C in brain affected by Tay-Sachs Disease.

Hexosaminidase (Hex) C could be detected in human brains by DEAE cellulose column chromatography, when N-acetyl-beta-D-glucosaminidase activity was determined at pH 5.5. In the chromatographic pattern, the peak of Hex C was always higher than that of Hex A in control prenatal brains and conversely lower in postnatal brains. Hex C was not detected in the brains obtained from two cases of Tay-Sachs disease. In addition, the content of Hex C in the brains of two other Tay-Sachs cases was lower than that of the control. The observation suggests that the absence or reduction of Hex C may have some relation with biochemical defects in Tay-Sachs disease, although Hex C does not share common subunit structures with Hex A and the role of Hex C with respect to GM2-ganglioside degradation remains unknown yet.

Brain↗
PubMed1981

Acidic glycosaminoglycans in liver from five patients with mucopolysaccharidosis and mucolipidosis.

Content, composition and molecular weight distribution of acidic glycosaminoglycans (GAGs) were determined in liver from five patients with genetic lysosomal storage diseases (Hurler syndrome, Hunter syndrome of severe type, Morquio syndrome, GM1-gangliosidosis type II and I-cell disease). There was a 30- to 40-fold increase in GAGs content of liver from patients with Hurler and Hunter syndromes. The GAGs accumulated in the livers consisted mainly of heparan sulfate and dermatan sulfate, and had a much lower molecular weight than those from control liver. The major GAG accumulated in liver from Morquio syndrome was keratan sulfate, which was not found in the livers from control and other patients, and chondroitin-6-sulfate was also increased. The content and the composition of liver GAGs from GM1-gangliosidosis and I-cell disease were similar to those of control liver. However, there was about a 33-fold increase in the amount of hexose on the liver GAGs from GM1-gangliosidosis. A molar ratio of sialic acid to hexosamine was 1.35 for the liver GAGs from I-cell disease and that of hexose to hexosamine was 8.47, while they were 0.46 and 2.32, respectively, for the control liver.

Adolescent↗
PubMed1981

Lymphoblastoid cell lines, transformed by Epstein-Barr virus, in the enzymatic study of hereditary lysosomal storage diseases.

Assay conditions were studied for eight lysosomal enzymes in lymphoblastoid cell lines transformed by Epstein-Barr virus. The transformed lymphoblastoid cells retained all eight enzyme activities, though the levels sometimes differed from those in the peripheral lymphocytes or granulocytes. The levels of these eight lysosomal enzymes were measured in lymphoblastoid cells from 11 patients with hereditary lysosomal storage diseases--GMI-gangliosidosis, a variant of beta-galactosidase deficiency (sialidase deficiency with a partial beta-galactosidase deficiency), Tay-Sachs disease, Gaucher disease, Hurler syndrome, Scheie syndrome and I-cell disease--and from 20 of their obligate heterozygotes. No activity of enzymes that were deficient in the respective disease, except I-cell disease, was detected in the lymphoblastoid cells from the patient. In I-cell disease, the cells showed lower levels of some enzyme activities. beta-D-Galactosidase activity from heterozygotes of the patient with GMI-gangliosidosis and alpha-L-iduronidase activity from heterozygotes of the patient with Hurler syndrome were in carrier range. On sephadex G-150 gel filtration, beta-D-galactosidase in control material gave two peaks (I and II). In GMI-gangliosidosis, peak II was absent and peak I was markedly diminished. Peak II in the heterozygotes was smaller than that of control. On DEAE cellulose column chromatography of hexosaminidase, two major isoenzymes (hexosaminidase A and B) were detected in control. However, hexosaminidase A was not detected in Tay-Sachs disease, and the ratios of hexosaminidase (Hex) A/Hex B in the parents were lower than those in control.

Cell Line↗
PubMed1981

A new transport interaction of dibasic amino acids and citrulline in human kidney.

The oral loading tests of lysine in 9 healthy men and the intravenous loading tests of lysine, ornithine and arginine in 3 healthy men were carried out. The results indicated that the membrane transport system of citrulline in the human kidney was clearly inhibited by dibasic amino acids, lysine, ornithine, and arginine.

Amino Acids↗
PubMed1980

A study of urea-synthesizing enzymes in prenatal and postnatal human liver.

The urea-synthesizing enzymes of human liver tissues, namely, carbamylphosphate synthetase (CPS, EC 2.7.2.2), ornithine transcarbamylase (OTC, EC 2.1.3.3), arginine synthetase system, argininosuccinase (ASase, EC 4.3.2.1), and arginase (EC 3.5.3.1) were measured between pre- and postnatal periods. Specimens from 67 autopsied human livers obtained from fetuses, premature infants, newborn infants, infants, children, and adults were examined. The mean activities of the enzymes showed an increased pattern for OTC and arginase at fetal life, whereas those of CPS, arginine synthetase system, and ASase of fetal livers showed no significant difference in each stage. Except for arginase, the other four enzyme activities were higher in the postnatal period than those in the fetal life. Arginase activities indicated maximal increase at a gestational age between 28 and 31 weeks and decreased in the postnatal life.

Adult↗
PubMed1980

Fluorometric measurement of alpha-L-iduronidase activity using 4-methylumbelliferyl-alpha-L-iduronide.

Using 4-methylumbelliferyl-alpha-L-iduronide as a substrate, alpha-L-iduronidase activity was measured in leukocytes and in lymphoblastoid cells obtained from patients with alpha-L-iduronidase deficiency and from obligate heterozygotes for this disease. There was complete discrimination between alpha-L-iduronide in leukocytes and in lymphoblastoid cells from the patients and controls. However, overlap was observed between values of the activity in the obligate heterozygotes and those in the controls. 4-Methylumbelliferyl-alpha-L-iduronidase activity because of greater sensitivity, easier assay procedure and shorter incubation period.

Female↗
PubMed1980

Activities of N-acetylgalactosamine-6-sulfate sulfatase in liver from two sisters with morquio syndrome.

A 6-sulfated tetrasaccharide obtained by digesting chondroitin-6-sulfate with testicular hyaluronidase was used as a substrate for the determination of N-acetylgalactosamine-6-sulfate sulfatase activity. The activity was not detected in liver obtained from the elder sister with clinically classic Morquio syndrome and 4.7% of the control in liver from the younger sister with the same disease.

Adolescent↗
PubMed1980

An altered hexosaminidase A in the liver affected by Hurler and Hunter syndromes.

Total hexosaminidase (Hex) in the liver obtained from Hurler and Hunter syndromes displayed about ten times higher activity than that in control liver and moreover, its thermostability was significantly increased. On DEAE cellulose column chromatography, Hex A in the liver of those patients was eluted at much higher salt concentration than that required for elution of Hex A from control liver. There was no difference in elution patterns of Sephadex G-200 and Concanavalin A-Sepharose column chromatographies between the altered Hex A and control Hex A. It appears that the glycosaminoglycans accumulating in the liver of those patients are partly bound to Hex A, and that this binding may cause some changes of its properties such as ionic charge and thermostability.

Adolescent↗
PubMed1979

Neuraminidase activity in liver and brain from patients with I-cell disease.

The activity of neuraminidase in liver and brain from I-cell disease (Mucolipidosis II) was investigated. Neuraminidase activities using two substrates [alpha-L-N-acetylneuraminosyl(2 leads to 3)lactose and alpha-L-N-acetylneuraminosyl(2 leads to 6)lactose] were reduced in the supernatant and sedimentable fractions obtained in isotonic KCl. The activity of beta-D-galactosidase was also reduced in the liver; on the other hand, both neuraminidase fractions were normal, although beta-galactosidase activities were markedly reduced. In view of these results, it is suggested that the defect of neuraminidase is not directly responsible for the primary etiology of I-cell disease.

Brain↗
PubMed1979

Identification of keratan sulfate in liver affected by Morquio syndrome.

Glycosaminoglycan content, composition and molecular weight were determined in liver obtained from a patient with Morquio syndrome (Mucopolysaccharidosis IV). There was about a four-fold increase in glycosaminoglycan content (as hexosamine) of the affected liver as compared to the control liver. The major glycosaminoglycan accumulated in the liver was keratan sulfate, which was not found in the control liver. Chondroitin sulfates, especially chondroitin 6-sulfate, were also increased. Heparan sulfate isolated from the liver of a patient with Morquio syndrome was structurally different to that from control liver, and the glycosaminoglycans from Morquio syndrome were of a much lower molecular weight than those from control.

Adolescent↗
PubMed1979

Sphingomyelinase activities in cultured skin fibroblasts from patients with Niemann-Pick Disease.

Sphingomyelinase activity in cultured skin fibroblasts from a fetus affected with infantile-type Niemann-Pick disease was 0.5% of control activity; the activities in cells from two patients with adult-type disease (Cases 2 and 3) were 5.0% and 59.0%. Sphingomyelinase activiy was separated into three peaks (I-III) by isoelectric focusing. The isoelectric points were 4.5, 4.9, and 5.2 for peaks I, II, and III, respectively. The three peaks in the Case 2 cells were drastically reduced; only a very small peak could be distinguished (pI of 4.7). On the other hand, three peaks were observed in the Case 3 cells. Peak I had a pI of 4.4, peak II a pI of 4.7, and peak III a pI of 5.2. Peak I was found at near normal level, but both peaks II and III were markedly reduced. Sphingomyelinase in the peak I fraction obtained from isoelectric focusing in Case 3 cells was found to have the same Km value as that in control cells.

Adult↗