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H Sakuraba

Publications and source records attributed to H Sakuraba.

At least 91 records · Page 5Linked to original sources
PubMed1995

An atypical variant of Fabry's disease in men with left ventricular hypertrophy.

BACKGROUND: Fabry's disease is considered very rare. Left ventricular hypertrophy is one of the common manifestations in adults with classic hemizygous disease. Recently, several cases of an atypical variant of hemizygous Fabry's disease, with manifestations limited to the heart, have been reported. Therefore, we assessed the incidence of hemizygosity for Fabry's disease among male patients with left ventricular hypertrophy. METHODS: We measured plasma alpha-galactosidase activity in 230 consecutive male patients with left ventricular hypertrophy. Clinical manifestations were assessed, endomyocardial biopsies were performed, and the patients were screened for mutations in the alpha-galactosidase gene. RESULTS: Seven of the 230 patients with left ventricular hypertrophy (3 percent) had low plasma alpha-galactosidase activity (0.4 to 1.2 nmol per hour per milliliter; 4 to 14 percent of the mean value in normal controls). These seven unrelated patients, ranging in age from 55 to 72 years, did not have angiokeratoma, acroparesthesias, hypohidrosis, or corneal opacities, which are typical manifestations of Fabry's disease. Endomyocardial biopsy was performed in five patients and revealed marked sarcoplasmic vacuolization in all five. Samples from four patients were examined by electron microscopy and revealed typical lysosomal inclusions with a concentric lamellar configuration in all four. Two patients had novel missense mutations in exon 1 (Ala20Pro) and exon 6 (Met296lle). The remaining five had no mutations in the coding region of the alpha-galactosidase gene, but the amounts of the alpha-galactosidase messenger RNA were markedly lower than normal. CONCLUSIONS: Seven unrelated patients with atypical variants of hemizygous Fabry's disease were found among 230 men with left ventricular hypertrophy (3 percent). Fabry's disease should be considered as a cause of unexplained left ventricular hypertrophy.

Adolescent↗
PubMed1995

A novel missense mutation (C522Y) is present in the beta-hexosaminidase beta-subunit gene of a Japanese patient with infantile Sandhoff disease.

A novel missense mutation (1565G-->A) was identified in the cDNA and genomic DNA coding for the beta-hexosaminidase beta-subunit of a Japanese patient with infantile Sandhoff disease. The patient was homozygous for this mutation, which should result in a cysteine-to-tyrosine substitution at codon 522. Computer-assisted analysis of this amino acid substitution predicted alteration in the secondary structure in the region of a highly conserved sequence. An immunofluorescence study revealed the accumulation of GM2 ganglioside in cultured fibroblasts from the patient with this mutation.

Base Sequence↗
PubMed1995

The functional role of glutamine-280 and threonine-282 in human alpha-galactosidase.

Our previous study on chimeric mutants of alpha-galactosidase suggested that two peptide regions encoded by exons 1-2 and 6 of the enzyme gene contribute to substrate recognition (Ishii, S. et al. (1994) Biochim. Biophys. Acta 1204, 265-270). In this study, we constructed five single amino acid substitutions for functional analysis of the amino acid residues around glutamine-279, the mutation site detected in an atypical Fabry disease patient. Two mutants, Q280S (Gln280-->Ser; CAA-->TCA) and T282A (Thr282-->Ala; ACT-->GCT), showed increased Km and decreased thermostability as compared with normal enzyme. Circular dichroism spectrum was not modified. An additional chimeric mutation in the exon 1-2 region by substitution with the homologous sequence of alpha-N-acetylgalactosaminidase cDNA restored catalytic activity and thermostability in both mutants. These data indicated the functional significance of glutamine-280 and threonine-282 for expressing the activity and stability of alpha-galactosidase molecule, and also the presence of an intramolecular interaction between the two peptide regions encoded by exons 1-2 and 6.

Amino Acid Sequence↗
PubMed1995

Protective protein as an endogenous endothelin degradation enzyme in human tissues.

An enzyme hydrolyzing the carboxyl terminus of endothelin-1 was detected in control human tissues but was deficient in tissues from a patient with galactosialidosis, a metabolic disease caused by the protective protein gene mutation. It was proportional to the amount of immunologically estimated mature protective protein. An antibody against the lysosomal protective protein/beta-galactosidase complex precipitated the enzyme activity almost completely. Transfection of the human cDNA for protective protein resulted in high expression of the enzyme activity in transformed fibroblasts from a galactosialidosis patient. These results indicated that the mature protective protein is a major soluble endogenous endothelin degradation enzyme in human tissues.

Brain↗
PubMed1995

Alcohol:NAD+ oxidoreductase is present in rat liver peroxisomes.

Alcohol:NAD+ oxidoreductase was found in the peroxisomes of animal liver for the first time as follows. The distribution of alcohol:NAD+ oxidoreductase activity with nonanol as substrate in the light mitochondrial fraction (peroxisome-enriched fraction) of rat liver was examined by centrifugation in a sucrose density gradient. Most of the enzyme activity was localized in the mitochondria, with some activity in the peroxisomes. The administration of clofibrate, a peroxisome proliferator, to rats resulted in a marked increase of the enzyme activity in the peroxisomes, but not in the mitochondria. The enzyme was found to be located in the matrix of the peroxisomes. The evidence was obtained that the enzyme differed from alcohol dehydrogenases and alcohol oxidizing systems found previously. The enzyme activity was not affected by pyrazole, an inhibitor of alcohol dehydrogenase and sodium azide, an inhibitor of catalase. The enzyme was NAD(+)-dependent and oxidized straight chain aliphatic alcohols with a variety of carbon chains (C2-C18), showing the maximum on nonanol. Km values toward these aliphatic alcohols decreased with increasing chain length. The major reaction product was identified as the carboxylic acid by using high performance liquid chromatography.

Alcohol Dehydrogenase↗
PubMed1995

Alpha-galactosidase gene mutations in Fabry disease: heterogeneous expressions of mutant enzyme proteins.

Five point mutations were identified in unrelated Japanese Fabry disease hemizygotes: three new missense mutations, C142Y (425 G-->A), A156V (467 C-->T), and L166V (496 C-->G) in exon 3; one new splice site mutation at the 3' end of the consensus sequence in exon 4; one previously reported nonsense mutation, W44X (131 G-->A). C142Y expressed 50% of the normal enzyme protein in COS-1 cells, but catalytic activity was not detected. Both A156V and L166V expressed significant amounts of residual enzyme activity (6.7% and 9.8%) and enzyme proteins (10% each), the latter were more thermolabile at neutral pH than at acid pH, in vitro.

Adolescent↗
PubMed1995

A female heterozygous patient with Fabry's disease with renal accumulation of trihexosylceramide detected with a monoclonal antibody.

We describe a female patient with heterozygous Fabry's disease. The patient had persistent proteinuria and microhematuria but lacked any other diagnostic signs such as corneal and cutaneous involvement. Kidney tissue obtained at biopsy showed the segmentally distributed enlarged glomerular epithelia. These cells were filled with vacuolated foamy cytoplasm, which had lamellar and myelinoid structures under electronmicroscopic observation. Accumulation of trihexosylceramide (CTH) in these foamy epithelial cells was confirmed with immunohistochemical staining with the use of anti-CTH monoclonal antibody. Alpha-galactosidase activity of leukocytes was 67 nmol/mg protein/hr, which was approximately half that of the normal population (mean +/- SD, 147 +/- 65 nmol/mg protein/hr, n = 20). All of these findings were compatible with the diagnosis of heterozygous Fabry's disease. We recommend that kidney tissue biopsy specimens suggesting Fabry's disease be immunostained with anti-CTH antibody.

Antibodies, Monoclonal↗
PubMed1995

Clinical and molecular analysis of a Japanese boy with Morquio B disease.

Morquio B disease was found in a 15-year-old Japanese boy who presented with progressive generalized skeletal dysplasia without neurological manifestations. Mild keratan sulfaturia was found, and beta-galactosidase was deficient in fibroblasts. Gene analysis revealed two mutant alleles, 83Tyr-->His (Y83H) and 482Arg-->Cys (R482C). The former expressed a low enzyme activity (2-5% of normal), and the latter expressed no detectable enzyme activity.

Adolescent↗
PubMed1995

Detection of donor lymphocytes in the cerebrospinal fluid of a patient with metachromatic leukodystrophy following bone marrow transplantation.

An unrelated donor bone marrow transplant (UD-BMT) was carried out on a 10-year-old patient with metachromatic leukodystrophy (MLD). We collected cerebrospinal fluid (CSF) on day +168 and cultured it with recombinant IL-2 and PHA-P to examine the origin of cells in the CSF. Analysis on variable number of tandem repeat (VNTR) of lymphocytes in the CSF amplified by PCR revealed that lymphocytes in the CSF were of donor origin. These data support that BMT at an early stage may prevent deterioration in MLD. Although the patient developed grade III acute GVHD with rash and diarrhea, we successfully treated acute GVHD using rabbit anti-human thymocyte immunoglobulin (ATG). UD-BMT may be an alternative treatment for patients with MLD in the absence of an HLA matched family donor.

Bone Marrow Transplantation↗
PubMed1995

[Fabry disease (alpha-galactosidase deficiency)].

Fabry disease is an X-linked glycosphingolipid storage disorder resulting from a deficiency of lysosomal alpha-galactosidase (alpha-Gal; EC 3.2.1.22). Classical form patients, with clinical manifestations of generalized angiopathy of early onset, usually show no detectable alpha-Gal activity. There are also atypical form patients with residual alpha-Gal activity and late onset cardiomyopathy without other systemic manifestations. We identified a number of alpha-Gal gene mutations including partial deletions and point mutations. They were heterogeneous and more than half of them were missense mutations. Various missense mutants were expressed in COS-1 cells. Two groups have been identified; one expressing a mutant enzyme without catalytic activity, and the other expressing a catalytically active but unstable mutant enzyme. The latter was restored in patient cells by the addition of substrate analogues. The molecular genetic and biochemical analysis for Fabry disease will provide us with significant informations on the pathogenesis and the possibility of the therapeutic approach for this disease.

Analgesics, Non-Narcotic↗
PubMed1994

Distribution of lysosomal protective protein in human tissues.

We raised two polyclonal antibodies against synthetic oligopeptides comprising amino acid sequences in the human lysosomal protective protein. The first antibody recognized the 54-kDa precursor and the N-terminal sequence of the 32-kDa mature protein subunit, and the second one recognized the precursor and the C-terminal sequence of the 20-kDa subunit. In normal fibroblasts, mature protective protein was detected on immunoblotting with these antibodies. Considerable amounts of mature protective protein also were detected in kidney, lung, liver, and spleen, but not in brain from a patient with Gaucher disease. Neither the precursor nor the mature protective protein was detected in cultured fibroblasts, liver or cerebrum from a galactosialidosis patient with protective protein deficiency.

Animals↗
PubMed1994

Identification of chicken liver mitochondrial alanine:2-oxoglutarate aminotransferase and its response to starvation.

In chicken liver, alanine:2-oxoglutarate aminotransferase was located only in the mitochondria. In 40-day-old chickens, starvation resulted in a dramatic increase of liver mitochondrial alanine:2-oxoglutarate aminotransferase activity, reaching about a 100-fold increase in the activity (units/g of liver) on Day 7 of starvation. The mitochondrial alanine:2-oxoglutarate aminotransferase was purified to homogeneity and characterized from the mitochondrial extract of 7-day-starved chicken liver. The enzyme possessed alanine:glyoxylate aminotransferase activity and was also present in control chicken liver. The enzyme was found in the present study for the first time and named alanine:2-oxoglutarate (glyoxylate) aminotransferase. Alanine:2-oxoglutarate aminotransferase specific for alanine and 2-oxoglutarate as substrates was not detected in both control and starved chicken livers. In contrast, liver mitochondrial alanine:2-oxoglutarate aminotransferase from mammals did not possess alanine:glyoxylate aminotransferase activity. The increase in mitochondrial alanine:2-oxoglutarate aminotransferase activity during starvation was found to be attributed to an increase in enzyme protein.

4-Aminobutyrate Transaminase↗
PubMed1994

Human alpha-galactosidase gene expression: significance of two peptide regions encoded by exons 1-2 and 6.

Two proteins with alpha-galactosidase activity, alpha-galactosidase A (alpha-GalA) and alpha-galactosidase B (alpha-GalB, or alpha-N-acetylgalactosaminidase; alpha-NAGA) have a high homology of amino-acid sequence. Point mutations of the alpha-GalA gene have been reported only in the exons 1, 2 or 6. In this study, the exon 1-2 and/or 6 sequences of alpha-GalA cDNA were partly substituted by the corresponding regions of alpha-GalB cDNA, and three chimeric proteins were prepared by the baculovirus expression system: CMB12 with substitution at the exon 1-2 region, CMB6 at the exon 6 region, and CMB126 at both regions. They all preserved alpha-GalA antigenicity. Their kinetic properties toward 4-methylumbelliferyl alpha-galactopyranoside were compared with those of alpha-GalA. The catalytic activity was slightly low in CMB12, decreased to 1/10 in CMB6, and restored to a significant degree in CMB126. Km was more than 4-fold higher for CMB6 and CMB126 than for alpha-GalA. The pH optimum was 4.0 for both CMB12 and alpha-GalA, 4.8 for CMB6, and 4.6 for CMB126 and alpha-GalB. The catalytic activity was inhibited most by galactosamine in CMB6, and less in alpha-GalB, CMB126, alpha-GalA and CMB12 in decreasing order. The 50% inhibition concentrations of melibiose (Gal alpha 1-6Glc) and methyl alpha-galactopyranoside were 2.5- to 3-fold higher for CMB126 than for alpha-GalA. These results indicate that the low affinity of CMB126 to the substrate was caused by a reduced affinity to terminal alpha-linked galactose. We conclude that (1) the two regions encoded by exons 1-2 and 6 contribute to the alpha-galactosidic cleavage, and (2) an increase in Km of CMB6 or CMB126, with chimeric substitutions at the exon 6 region, was caused by a loss of affinity toward terminal alpha-linked galactose.

Amidohydrolases↗
PubMed1994

Platelet glycoprotein IV (CD36) deficiency is associated with the absence (type I) or the presence (type II) of glycoprotein IV on monocytes.

Platelet membrane glycoprotein (GP) IV (also called CD36 and GPIIb) deficiency is associated with N(aka)-negative platelets. Using flow-cytometric analysis of cells stained with the monoclonal anti-GPIV antibody OKM5, we have studied the expression of GPIV on the monocytes from 16 healthy Japanese individuals whose platelets were deficient in GPIV. GPIV was absent on the surface of monocytes from 2 platelet GPIV-negative donors (type I), whereas it was present on the monocytes from the remaining 14 platelet GPIV-negative donors (type II). The fluorescent intensity of OKM5-stained type II monocytes was significantly (P < .05) lower than that of normal monocytes derived from platelet GPIV-positive donors, suggesting that the expression of GPIV on the type II monocytes is also abnormally regulated as compared with that on normal monocytes. OKM5 induced an oxidative burst in the type II monocytes as well as in the normal monocytes, but it failed to induce it in the type I monocytes. Because the 2 individuals with the type I deficiency have been healthy and exhibited no immunologic problems, GPIV appears to be not essential for the normal physiologic functions of monocytes. An anti-GPIV antibody was detected in the serum from one of the type I GPIV-deficient women, who had never received any blood transfusions but had given birth to three apparently healthy children. These results suggest that type I GPIV-deficient individuals may be at risk of developing an anti-GPIV isoantibody upon blood transfusion or pregnancy.

Antibodies↗
PubMed1994

Intracellular processing and maturation of mutant gene products in hereditary beta-galactosidase deficiency (beta-galactosidosis).

Heterogeneous patterns of biosynthesis, posttranslational processing, and degradation were demonstrated for mutant enzymes in three clinical forms of beta-galactosidase deficiency (beta-galactosidosis): juvenile GM1-gangliosidosis, adult GM1-gangliosidosis, and Morquio B disease. The precursor of the mutant enzyme in adult GM1-gangliosidosis was not phosphorylated, and only a small portion of the gene product reached the lysosomes. The enzyme in Morquio B disease was normally processed and transported to lysosomes, but its catalytic activity was low. A common gene mutation in juvenile GM1-gangliosidosis (R201C) produced an enzyme protein that did not aggregate with protective protein in the lysosome, and was rapidly degraded by thiol proteases. This abnormal turnover was similar to that for the normal but dissociated beta-galactosidase in galactosialidosis. Protease inhibitors restored the enzyme activity in fibroblasts of this clinical form. A possible therapeutic approach is discussed for this specific type of enzyme deficiency.

Adult↗
PubMed1994

Normal serum beta-galactosidase in juvenile GM1 gangliosidosis.

GM1 gangliosidosis is a genetic disease with lysosomal beta-galactosidase deficiency caused by mutations of the gene coding for this enzyme. However, apparently normal enzyme activity was found in plasma or serum from juvenile GM1 gangliosidosis patients homozygous for a mutation, R201C (201Arg-->Cys), after clotting for 30 min. This extracellular fluid finding is unusual in patients with primary and genetic deficiency of beta-galactosidase. The serum enzyme activity became relatively low only after 3 1/2-hour clotting because its increase in normal controls was not observed in these patients. beta-Galactosidase assay is not always reliable, particularly with serum or plasma as an enzyme source, for the diagnosis of hereditary beta-galactosidase deficiency, unless it is conducted under well-controlled conditions.

Adolescent↗
PubMed1994

Lysosomal enzyme replacement using alpha 2-macroglobulin as a transport vehicle.

Improvement of the delivery of exogenous enzymes is essential to achieve effective enzyme replacement therapy in lysosomal storage diseases. To test whether alpha 2-macroglobulin, an endogenous plasma protein, could serve as a transport vehicle of therapeutic agents to cells, alpha 2-macroglobulin and acid alpha-glucosidase or alpha-galactosidase A were coupled using two heterobifunctional cross-linking reagents. The alpha-glucosidase-alpha 2-macroglobulin conjugate was internalized and transported into lysosomes of acid alpha-glucosidase-deficient fibroblasts. The enzyme activity was stable after being taken up by the cells. Uptake of the conjugate resulted in the degradation of glycogen accumulated in lysosomes. The alpha-galactosidase A-alpha 2-macroglobulin conjugate was also internalized into the lysosomes of alpha-galactosidase A-deficient fibroblasts. Internalized alpha-galactosidase A-conjugate degraded globotriaosylceramide accumulated in lysosomes. The endocytosis of both conjugate was inhibited by alpha 2-macroglobulin-trypsin complex, indicating that the conjugates were endocytosed by an alpha 2-macroglobulin receptor system. These results showed the usefulness of alpha 2-macroglobulin as a transport vehicle of lysosomal enzymes for effective enzyme replacement.

Animals↗