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Biomedical subjects

Goro Takada

Publications and source records attributed to Goro Takada.

At least 37 records · Page 2Linked to original sources
PubMed2005

Leukoencephalopathy around a tumor cyst following intracystic methotrexate injection.

A 4-year-old female with choroid plexus carcinoma developed progressive disturbance of consciousness 2 years after postoperative treatment with radiotherapy, chemotherapy, and focal methotrexate injection into a residual tumor cyst. Magnetic resonance imaging revealed white matter lesions localized around the expanding large cyst. A malignant recurrence of choroid plexus carcinoma with a propensity of cerebrospinal fluid overproduction was suspected. However, daily drainage of cerebrospinal fluid from the cyst and treatment with glycerol and dexamethasone achieved improvement. Diffuse hypoperfusion over the lesions on single-photon emission computed tomography denied the possibility of residual tumor aggravation and together with subsequent atrophic changes confirmed that the lesions reflect localized leukoencephalopathy, possibly associated with methotrexate forced into the parenchyma as a result of the expanding intracystic high pressure.

Antimetabolites, Antineoplastic↗
PubMed2005

Cloning and sequencing of an exoglucanase gene from Streptomyces sp. M 23, and its expression in Streptomyces lividans TK-24.

A gene encoding exoglucanase (CBHII) of Streptomyces sp. M 23 was cloned and sequenced. The cbhII gene consisted of 1359 bp capable of encoding a polypeptide of 453 amino acids with a calculated molecular mass of 45,175 Da. The deduced amino acid sequence showed homology with those of cellulases belonging to family 6 of the glycosyl hydrolases. The cbhII gene was subcloned into the plasmid pSEV1 and expressed in Streptomyces lividans TK-24. The transformed cells were able to secrete the enzyme efficiently in an active form. The CBHII expressed by S. lividans TK-24 was purified to homogeneity by SDS-polyacrylamide gel and characterized. The recombinant CBHII was stable up to 50 degrees C and more than 30% of the original activity remained after heating at 100 degrees C for 10 min. The amino-terminal amino acid sequence of the recombinant CBHII was identified as GPAAPTARVD. These results agreed well with the properties of the authentic CBHII.

Amino Acid Sequence↗
PubMed2005

A hippocampal lesion detected by high-field 3 tesla magnetic resonance imaging in a patient with temporal lobe epilepsy.

Nearly 80% of patients with temporal lobe epilepsy have some types of lesion identified by conventional 1.5 tesla (T) magnetic resonance imaging (MRI). We performed high-field 3 T MRI in a 5-year-old patient with recurrent complex partial seizures who was diagnosed as having right temporal lobe epilepsy based on the results of single photon emission computed tomography and ictal video-electroencephalogram monitoring, because 1.5 T MRI failed to detect any abnormalities in the suspected region. High-field 3 T MRI revealed a small high-intensity lesion on fast spin-echo short inversion time inversion-recovery images of the hippocampus, possibly responsible for the seizures. This is the first report detecting a hippocampal lesion by 3 T MRI, which could not be found by conventional 1.5 T MRI.

Brain Injuries↗
PubMed2005

Acid sphingomyelinase: relation of 93lysine residue on the ratio of intracellular to secreted enzyme activity.

Acid sphingomyelinase (ASM) is the lysosomal enzyme responsible for the hydrolysis of sphingomyelin to ceramide and phosphocholine. An inherited deficiency of this enzymatic activity results in the Type A and B forms of Niemann-Pick disease (NPD). ASM is also readily secreted from cultured cells and can rapidly move from lysosomes to the cell surface upon stimulation by cytokines and other factors. Recent interest has focused on the role of this secreted/cell surface enzyme in ceramide-mediated signal transduction. We therefore sought to understand the mechanism(s) that might regulate intracellular targeting and secretion of this important hydrolase. Most lysosomal proteins are targeted to lysosomes in mammalian cells via the mannose 6-phosphate recognition system. Using cultured skin fibroblasts from I-cell disease patients, in which one of the enzymes responsible for mannose phosphorylation, GlcNAc-phosphotransferase, is deficient, we determined ASM activities in cell homogenates and media. The ratio of secreted to intracellular activity was approximately 8-fold greater in I-cell than in normal cells, indicating that mannose phosphorylation is important in the trafficking of this hydrolase. Most of the secreted activity required Zn+2 for full activity, supporting the concept that intracellular exposure of ASM to zinc within lysosomes is required for enzymatic activation. The recognition of lysosomal proteins by GlcNAc-phosphotransferase is mediated by protein structure, and a specific three-dimensional arrangement of lysine residues exposed on the surface of several enzymes has been shown to be critical for mannose phosphorylation. Alanine scanning mutagenesis of thirteen lysine residues in ASM demonstrated that 93lysine residue plays a critical role in ASM targeting since the K93A mutant had reduced intracellular activity, but enhanced secreted activity that was zinc responsive.

Animals↗
PubMed2005

Long-acting gonadotropin-releasing hormone analogue treatment for central precocious puberty in maternal uniparental disomy chromosome 14.

Uniparental disomy (UPD) is the inheritance of a chromosome pair from one parent and is increasingly recognized as a cause of abnormal phenotypes either due to imprinted genes or, in the case of isodisomy, to homozygosity of recessive alleles. Maternal uniparental disomy for chromosome 14 (matUPD[14]) may cause a characteristic phenotype including precocious puberty. Central precocious puberty (CPP) was diagnosed in a 6-year-old girl with some dysmorphic features, truncal obesity, small hands, and small feet. Cytogenetic analysis of her peripheral blood demonstrated chromosomal rearrangement: Robertsonian translocation 45, XX, der(13;14)(q10;q10). MatUPD(14) was demonstrated in the patient by haplotype analysis of chromosome 14, showing that the CPP is one of the features caused by matUPD(14). The CPP was successfully treated with higher dosage of long-acting gonadotropin releasing hormone (GnRH) analogue, Leuprolide, 90 microg/kg/month. This is the first report that describes GnRH analogue treatment for CPP associated with matUPD(14), suggesting that the GnRH analogue treatment is appropriate even for such a specific type of CPP.

Body Height↗
PubMed2004

Dexamethasone-induced prenatal alveolar wall thinning is associated with a decrease in EIIIA+ fibronectin isoform in the fetal rat lung.

BACKGROUND: Glucocorticoid hormones play an important role in architectural and biochemical lung maturation. Although much of the molecular mechanism of their action in the lung is not fully understood, glucocorticoids directly or indirectly regulate lung maturation. Indirect effects of glucocorticoids may involve the modulation of cell-cell or cell-matrix interactions. Fibronectin (FN) is the major constituent of the pulmonary extracellular matrix and exists in multiple isoforms arising from alternative RNA splicing. EIIIA is the major alternatively spliced segment, and its expression is regulated in a spatiotemporal and oncodevelopmental manner. OBJECTIVES: The present study focuses on the regulation of EIIIA-containing FN isoforms (referred to as EIIIA+ FN) by glucocorticoids in the developing lung. METHODS: Dexamethasone (DEX) or saline was injected daily into pregnant rats from day 15 of gestation (term = day 22) until 24 h before sacrifice. The expression of EIIIA+ FN and proliferating cell nuclear antigen (PCNA), a biochemical marker for cell proliferation, was investigated in the fetal rat lung. RESULTS: At day 20 of gestation (the canalicular stage), the DEX-treated lung showed a significant decrease in weight and saccular septal wall thickness, while the messenger RNA expression of the surfactant protein SP-B was increased in the DEX-treated lung, as compared with the control lung. The expression of EIIIA+ FN and PCNA around the distal airspaces was less extensive in the DEX-treated lung than in the control lung at day 20 of gestation. CONCLUSIONS: Given the finding in vitro that EIIIA+ FN regulated the cell cycle, our results suggest that the change of EIIIA+ FN expression in the DEX-treated lung affected pulmonary cell proliferation.

Alternative Splicing↗
PubMed2004

Novel reactions of L-rhamnose isomerase from Pseudomonas stutzeri and its relation with D-xylose isomerase via substrate specificity.

Escherichia coli strain JM 109 harboring 6 x His-tag L-rhamnose isomerase (L-RhI) from Pseudomonas stutzeri allowed a 20-fold increase in the volumetric yield of soluble enzyme compared to the value for the intrinsic yield. Detailed studies on the substrate specificity of the purified His-tagged protein revealed that it catalyzed previously unknown common and rare aldo/ketotetrose, aldo/ketopentose, and aldo/ketohexose substrates in both D- and L-forms, for instance, erythrose, threose, xylose, lyxose, ribose, glucose, mannose, galactose, altrose, tagatose, sorbose, psicose, and fructose. Using a high enzyme-substrate ratio in extended reactions, the enzyme-catalyzed interconversion reactions from which two different products from one substrate were formed: L-lyxose, L-glucose, L-tagatose and D-allose were isomerized to L-xylulose and L-xylose, L-fructose and L-mannose, L-galactose and L-talose, and D-psicose and D-altrose, in that order. Kinetic studies, however, showed that L-rhamnose with Km and Vmax values of 11 mM and 240 U/mg, respectively, was the most preferred substrate, followed by L-mannose, L-lyxose, D-ribose, and D-allose. Based on the observed catalytic mode of action, these new findings reflected a hitherto undetected interrelation between L-RhI and D-xylose isomerase (D-XI).

Aldose-Ketose Isomerases↗
PubMed2004

Neuroprotection of edaravone on hypoxic-ischemic brain injury in neonatal rats.

Edaravone has an inhibitory effect on lipid peroxidation by scavenging free radicals and prevents vascular endothelial cell injury. We examined whether edaravone was effective on hypoxic-ischemic (HI) brain injury in immature brain or not using the Rice-Vannucci model. The initial dose, 3 mg/kg (0.05 ml) of edaravone, was injected intraperitoneally just before hypoxic exposure. Subsequently, the same dose was injected every 12 h until the animals were killed. Controls received saline injection as the same protocol. Macroscopic evaluation of brain injury revealed that the neuroprotective effect of edaravone on HI brain after 48 h post HI. TUNEL showed that edaravone injection decreased neurodegeneration. Quantitative analysis of cell death using H&E-stained 2.5 microm sections showed that there was a trend for both necrotic and apoptotic cells to decrease in edaravone injection group. Edaravone injection inhibited the release of cytochrome c from mitochondria to cytosol and caspase-3 activation in cortex and hippocampus between 24 and 168 h post HI. Our results suggest that edaravone is protective after HI insult in the immature brain by decreasing both apoptosis and necrosis and also by inhibiting mitochondrial injury.

Animals↗
PubMed2004

Renovascular hypertension due to antithrombin deficiency in childhood.

Inherited antithrombin deficiency generally causes a predisposition toward vascular thrombus above the age of 15 years. A 1-year-old boy developed renal hypertension caused by renal artery obstruction due to thrombus formation. This thrombus formation was attributed to antithrombin deficiency caused by a novel SERPINCI gene mutation (AT III Akita, M352R). This suggests that antithrombin deficiency can cause renal artery obstruction, inducing renal hypertension through vascular thrombosis even in children.

Antithrombin III Deficiency↗
PubMed2004

Myocardial acceleration during isovolumic contraction as a new index of right ventricular contractile function and its relation to pulmonary regurgitation in patients after repair of tetralogy of Fallot.

BACKGROUND: Myocardial acceleration during isovolumic contraction (IVA) by Doppler tissue imaging has been proposed to be a new index of right ventricular contractile function that is unaffected by ventricular shape or loading conditions. OBJECTIVES: We sought to assess the use of IVA to evaluate right ventricular contractile function. METHODS: In all, 22 pediatric patients with pulmonary regurgitation (PR) after repair of tetralogy of Fallot (TOF) (8 +/- 3 years) and 27 age-matched children were examined. The degree of PR (mild, moderate, and severe) for patients with TOF was on the basis of pulsed and color Doppler findings. Using Doppler tissue imaging, the peak myocardial velocities during early diastole, late diastole, systole, and isovolumic contraction were recorded. RESULTS: Compared with healthy children, Doppler tissue imaging velocities for patients with TOF showed decreased myocardial velocities during early diastole (P =.007), late diastole (P <.0001), systole (P <.0001), and isovolumic contraction (P <.0001). Patients with TOF had a lower IVA when compared with healthy children (P <.0001). There was a stepwise decrease in the IVA from mild to severe PR. We found a significant relationship between the IVA and the degree of PR (r = -0.86, P <.0001). CONCLUSION: The analysis of IVA allows the assessment of right ventricular contractile function for patients with repaired TOF and various degrees of PR.

Acceleration↗
PubMed2004

Codevelopment of dendritic cells along with erythroid differentiation from human CD34(+) cells by tumor necrosis factor-alpha.

OBJECTIVE: Tumor necrosis factor-alpha (TNF-alpha) inhibits erythropoiesis and enhances nonerythroid colony formation. The present study examines the nature of these nonerythroid cells and investigates their physiologic role in relation to erythroid progenitor cells. MATERIALS AND METHODS: Highly purified human CD34(+) cells underwent erythroid differentiation in the presence of multiple cytokines, including stem cell factor (SCF), interleukin-3 (IL-3), and erythropoietin (EPO), with and without TNF-alpha. We enumerate colony-forming unit-erythroid (CFU-E) and glycophorin A (GPA; a specific marker for erythroid lineage) positive cells in semisolid phase as well as in liquid suspension culture. The character and roles of codeveloping nonerythroid cells in the presence of TNF-alpha were analyzed using fluorescent activating cell sorter, enzyme immunohistochemistry, and confocal microscopy. RESULTS: TNF-alpha inhibited the generation of GPA(+) cells and conversely enhanced the generation of GPA(-) cells. The GPA(-) cells were comprised of cells with excentric cell shape and were positive for HLA class I, HLA class II, CD1a, CD4, CD11c, CD14, CD40, CD80, CD83, and CD86, but not for CD3, CD8, CD19, CD20, and CD56, indicating the codevelopment of dendritic cells (DC) along with erythroid differentiation. Developing DC/DC precursors were detected within 3 days of culture. Only in the presence of TNF-alpha did CD34(+) cells proliferate by forming aggregates where both GPA(+) and CD11c(+) DC/DC precursors were present. During culture period, immature CD11c(+) DC were capable of endocytosing damaged GPA(+) cells. CONCLUSIONS: GPA(-) cells cogenerated from human CD34(+) cells during erythroid differentiation in the presence of IL-3/SCF/EPO and TNF-alpha express DC phenotypes. The CD11c(+) DC subset physically and selectively associates with developing immature erythroid cells and damaged self-GPA(+) cells and then obtains and captures self-substances.

Antigens, CD34↗
PubMed2004

Clinical heterogeneity of neonatal intrahepatic cholestasis caused by citrin deficiency: case reports from 16 patients.

A deficiency of citrin, which is encoded by the SLC25A13 gene, causes both adult-onset type II citrullinemia (CTLN2) and neonatal intrahepatic cholestasis (NICCD). We analyzed 16 patients with NICCD to clarify the clinical features of the disease. Severe intrahepatic cholestasis with fatty liver was the most common symptom, but the accompanying clinical features were variable, namely; suspected cases of neonatal hepatitis or biliary atresia, positive results from newborn screening, tyrosinemia, failure to thrive, hemolytic anemia, bleeding tendencies and ketotic hypoglycemia. Laboratory data showed elevated serum bile acid levels, hypoproteinemia, low levels of vitamin K-dependent coagulation factors, and hypergalactosemia. Hypercitrullinemia was detected in 11 out of 15 patients examined. Most of the patients were given a lactose-free and/or medium chain triglycerides-enriched formula and lipid-soluble vitamins. The prognosis of the 16 patients is going fairy well at present, but we should observe these patients carefully to see if they manifest any symptom of CTLN2 in the future.

Amino Acids↗
PubMed2004

A novel enzymatic approach to the massproduction of L-galactose from L-sorbose.

Wild-type strain of Pseudomonas cichorii ST-24 was unable to grow on D -psicose and inductively produced D -tagatose 3-epimerase (D -TE) with D -tagatose as an inducer. We have isolated a constitutive mutant, designated strain Ka75, which had acquired a new ability to grow on a mineral salts medium containing D -psicose as a sole carbon source. The D -psicose-metabolizing mutant synthesized a high level of D -TE. When grown on the culture medium supplemented with Mn(2+), the mutant strain produced around 250-fold higher activity than did the parent strain. Enzymatic properties of the constitutive enzyme were similar to those of the wild-type. Using the immobilized D -TE and recombinant L-rhamnose isomerase (L-RhI) from Escherichia coli strain JM109, a two-step enzymatic reaction was performed for massproduction of a rare aldo-hexose monosaccharide, L-galactose, from a common one, L-sorbose. In the first step, L-sorbose was epimerized to L-tagatose in a yield of 28%. The L-tagatose obtained was utilized as a starting material for L-galactose preparation by the immobilized L-RhI. At equilibrium, approximately 30% L-tagatose was isomerized to L-galactose. Finally, 7.5 g of L-galactose was obtained from 100 g of L-sorbose, viz an overall yield of 7.5%. The product obtained was purified and identified to be L-galactose by specific optical rotation and high performance liquid chromatography (HPLC) analysis, and was ultimately confirmed by (13)C nuclear magnetic resonance ((13)C NMR) and IR spectra.

Journal Article↗
PubMed2004

Cloning, nucleotide sequence, and overexpression of the L-rhamnose isomerase gene from Pseudomonas stutzeri in Escherichia coli.

The gene encoding L-rhamnose isomerase (L-RhI) from Pseudomonas stutzeri was cloned into Escherichia coli and sequenced. A sequence analysis of the DNA responsible for the L-RhI gene revealed an open reading frame of 1,290 bp coding for a protein of 430 amino acid residues with a predicted molecular mass of 46,946 Da. A comparison of the deduced amino acid sequence with sequences in relevant databases indicated that no significant homology has previously been identified. An amino acid sequence alignment, however, suggested that the residues involved in the active site of L-RhI from E. coli are conserved in that from P. stutzeri. The L-RhI gene was then overexpressed in E. coli cells under the control of the T5 promoter. The recombinant clone, E. coli JM109, produced significant levels of L-RhI activity, with a specific activity of 140 U/mg and a volumetric yield of 20,000 U of soluble enzyme per liter of medium. This reflected a 20-fold increase in the volumetric yield compared to the value for the intrinsic yield. The recombinant L-RhI protein was purified to apparent homogeneity on the basis of three-step chromatography. The purified recombinant enzyme showed a single band with an estimated molecular weight of 42,000 in a sodium dodecyl sulfate-polyacrylamide gel. The overall enzymatic properties of the purified recombinant L-RhI protein were the same as those of the authentic one, as the optimal activity was measured at 60 degrees C within a broad pH range from 5.0 to 11.0, with an optimum at pH 9.0.

Aldose-Ketose Isomerases↗
PubMed2004

Johanson-blizzard syndrome: loss of glucagon secretion response to insulin-induced hypoglycemia.

Johanson-Blizzard syndrome is a rare autosomal recessive disorder characterized by aplasia of the alae nasi, aplasia cutis, dental anomalies, postnatal growth retardation and pancreatic exocrine aplasia. Some endocrinological dysfunctions--growth hormone (GH) deficiency, hypothyroidism, and diabetes mellitus--are known to complicate this syndrome. We report here a Japanese infant with Johanson-Blizzard syndrome presenting with failure to thrive. Endocrinological examination by insulin-induced hypoglycemia showed not only the presence of GH deficiency, but also the loss of the glucagon secretion response to hypoglycemia. This complication suggests abnormal input of autonomic nerves to the islets of pancreas in Johanson-Blizzard syndrome.

Abnormalities, Multiple↗