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Biomedical subjects

S Tsuji

Publications and source records attributed to S Tsuji.

At least 847 records · Page 47Linked to original sources
PubMed1988

Genetic heterogeneity in type 1 Gaucher disease: multiple genotypes in Ashkenazic and non-Ashkenazic individuals.

Nucleotide sequence analysis of a genomic clone from an Ashkenazic Jewish patient with type 1 Gaucher disease revealed a single-base mutation (adenosine to guanosine transition) in exon 9 of the glucocerebrosidase gene. This change results in the amino acid substitution of serine for asparagine. Transient expression studies following oligonucleotide-directed mutagenesis of the normal cDNA confirmed that the mutation results in loss of glucocerebrosidase activity. Allele-specific hybridization with oligonucleotide probes demonstrated that this mutation was found exclusively in the type 1 phenotype. None of the 6 type 2 patients, 11 type 3 patients, or 12 normal controls had this allele. In contrast, 15 of 24 type 1 patients had one allele with this mutation, and 3 others were homozygous for the mutation. Furthermore, some of the Ashkenazic Jewish type 1 patients had only one allele with this mutation, suggesting that even in this population there is allelic heterozygosity. These findings indicate that there are multiple allelic mutations responsible for type 1 Gaucher disease in both the Jewish and non-Jewish populations. Allelic-specific hybridization demonstrating this mutation in exon 9, used in conjunction with the Nci I restriction fragment length polymorphism described as a marker for neuronopathic Gaucher disease, provides a tool for diagnosis and genetic counseling that is approximately equal to 80% informative in all Gaucher patients studied.

Adolescent↗
PubMed1988

Glycosylation and processing of high levels of active human glucocerebrosidase in invertebrate cells using a baculovirus expression vector.

A human cDNA containing the complete coding region for the lysosomal glycoprotein glucocerebrosidase (EC 3.2.1.45) was introduced into the genome of Autographa californica nuclear polyhedrosis virus downstream from the polyhedrin promoter. Infection of Spodoptera frugiperda cells (SF9) with recombinant virus produced high levels of glucocerebrosidase, 40% of which was in the culture medium. The amino-terminal amino acid sequence of the recombinantly produced enzyme was identical to that of mature, human placental glucocerebrosidase, demonstrating that the signal sequence of the human preenzyme was recognized and appropriately removed in the SF9 invertebrate cells. The glucocerebrosidase in both the culture supernatant and SF9 cell pellet was glycosylated and contained, in part, high mannose oligosaccharide. These results demonstrate that insect cells can be used to produce abundant quantities of active mature human glucocerebrosidase that contains high mannose oligosaccharide as a consequence of post-translational processing.

Animals↗
PubMed1988

A novel, carbohydrate signal-mediated cell surface protein phosphorylation: ganglioside GQ1b stimulates ecto-protein kinase activity on the cell surface of a human neuroblastoma cell line, GOTO.

A ganglioside-stimulated ecto-type protein phosphorylation system (ecto-Gg-kinase) was detected on the cell surface of a human neuroblastoma cell line (GOTO). When intact cells were incubated with [gamma-32P]ATP, at least 28 cell surface proteins were phosphorylated, as evident on SDS-PAGE (4-20%) analysis. Exogenously added gangliosides specifically stimulated the phosphorylation of at least three cell surface associated proteins of Mr = 64,000, 60,000, and 54,000. Phosphorylation was directed toward Thr and Ser residues, respectively, as revealed on acid hydrolysis followed by electrophoresis. GQ1b, at 5 nM, was the most potent among the several gangliosides tested and was more effective when added to cells before [gamma-32P]ATP administration. The simultaneous addition of an excess amount of the saccharide portion of GQ1b (oligo-GQ1b) inhibited the GQ1b-stimulated phosphorylation, indicating the necessity of the sialosaccharide moiety. These results strongly suggest that phosphorylation of the three proteins may be closely associated with the highly specific neuritogenic effect of GQ1b previously reported.

Cell Line↗
PubMed1988

Microvascular basis of gastric mucosal protection.

The gastric microcirculation was investigated with the in vivo microscopic analyzing system and reflectance spectrophotometry. The topical administration of either ethanol (greater than or equal to 20%), indomethacin (0.1 mg/kg), leukotriene C4 (0.1 microgram), and platelet activating factor (PAF) (125 micrograms) decreased mucosal blood flow and mucosal blood oxygenation. The subsequent reperfusion of blood and/or addition of hydrocholoride (0.2 N) induced the gastric bleeding and ulceration. Pretreatment with calcium channel blockers (verapamil, flunaridine, and diltiazem) significantly reduced the gastric lesions induced by mucosal ischemia followed by reperfusion. Lipid peroxidation increased only after reperfusion, which was also blocked by pretreatment with calcium channel blockers. Thus, the calcium ion influx and the membrane lipid peroxidation followed by mucosal hypoxia might have a role in the mucosal cell death. The results indicate that the gastric surface mucosal circulation plays an important role in the mucosal protection against high concentrations of ethanol, nonsteroidal anti-inflammatory drugs (NSAIDs), PAF, and leukotriene C4.

Animals↗
PubMed1988

Direct autoradiographic comparison of 99Tcm-HMPAO with 125I-IMP in experimental brain ischaemia.

Local cerebral blood flow (LCBF) images of HMPAO and IMP were directly compared in experimental brain ischaemia in the same rats using a double-tracer autoradiographic technique. Both images were identical in distribution throughout the whole flow areas. However, LCBF values were much lower in HMPAO than in IMP. The results suggest that HMPAO acts as a chemical microembolus in rat brain in both low and high flow areas; however, a quantitative flow measurement is difficult in an HMPAO study.

Amphetamines↗
PubMed1988

Clonal origin of gamma-glutamyl transpeptidase-positive hepatic lesions induced by initiation-promotion in ornithine carbamoyltransferase mosaic mice.

Since the deficiency of ornithine carbamoyltransferase (OCT) is inherited as an X-linked dominant trait in sparse-fur with abnormal skin and hair (Spf-ash) mice, the livers of heterozygous Spf-ash females show mosaicism in regard to OCT. We induced enzyme-altered foci and nodules, presumptive preneoplastic lesions for hepatocellular carcinomas, in the livers of OCT mosaic mice (Spf-ash x C3H F1), and investigated the clonality of the lesions. Simultaneous histochemical staining for OCT and gamma-glutamyl transpeptidase (GGT) demonstrated that all GGT-positive lesions (ranging in size from 3 cells to a few millimeters in diameter) were either positive or negative for OCT, and no mosaic lesions were detectable. The results indicate that individual enzyme-altered hepatocytic lesions are the result of clonal proliferation.

Animals↗
PubMed1988

Synthetic sialyl compounds as well as natural gangliosides induce neuritogenesis in a mouse neuroblastoma cell line (Neuro2a).

Amphipathic compounds containing N-acetylneuraminic acid (sialic acid) [for example, D-N-acetylneuraminyl-(alpha 2-1)-2S,3R,4E-2-N-tetracosanoyl sphingenine, sialyl alkyl glycerol ethers, and sialyl cholesterols] induced neuritogenesis in a neuroblastoma cell line (Neuro2a). The sialic acid in the hydrophilic moiety of the compounds is specifically required for neuritogenesis. The requirement for molecular specificity of the hydrophobic moiety, however, is rather low. Regarding the hydrophobic moiety, no preference for cholesterol, alkyl glycerol ether, or ceramide residues was observed as to their neuritogenic activity. Sialyl compounds with alpha-ketosidic sialyl linkages were more active than the corresponding beta-anomers. These sialyl compounds induced the growth of only one neurite, but a long one, from the cell body. This type of neuritogenes is completely different from that induced by compounds capable of elevating the concentration of intracellular cyclic AMP, which induced the appearance of many neurites from a single cell body. Besides this morphological change, the active sialyl compounds also caused a change in the carbohydrate composition of the cell surface. Sialyl compound treatment drastically increased the concentration of peanut agglutinin binding sites.

Animals↗
PubMed1988

Fragile X expression in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids under low and high thymidylate stress conditions.

Expression of the fragile X site fra(X)(q27.3) was studied in thymidine-prototrophic and auxotrophic human-mouse somatic cell hybrids. In these cells, low thymidylate stress, achieved by 5-fluoro-2'-deoxyuridine (FdU) treatment and by limiting the exogenous supply of thymidine (dT), induced fragile X expression. High thymidylate stress, produced by supplying excess amounts of dT, was also effective in inducing fragile X expression, even in a hybrid clone that retained a fragile X chromosome as the only human chromosome; addition of deoxycytidine (dC) completely abolished this effect. In contrast, 5-bromo-2'-deoxyuridine (BrdU) did not induce fragile X expression. Cell-cycle analysis of BrdU-deprived thymidine-auxotrophic hybrid cells indicated that one round of DNA replication under thymidylate stress conditions is sufficient for fragile X expression. Our results suggest that the expression is an intrinsic property of the fragile site itself, which is believed to be composed of replicon clusters with pyrimidine-rich DNA sequence(s).

Animals↗
PubMed1988

Supraventricular tachycardia in a patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy.

Electrophysiologic study of a 55-year-old patient with Lown-Ganong-Levine syndrome associated with apical hypertrophic cardiomyopathy is reported. The patient had a history of recurrent attacks of tachyarrhythmia and his electrocardiogram showed a short P-R interval (0.10 sec) with narrow QRS complex and left ventricular hypertrophy with giant negative T waves. His cineangiogram showed severe apical hypertrophy. An electrophysiologic study was performed. The results of programmed atrial pacing show the existence of the dual A-V nodal pathways. The A-H interval at rapid atrial pacing increased maximally by 103 msec. Atrial stimulation could depolarize parts of the atrium without altering the supraventricular tachycardia. These findings suggested that preferential rapidly conducting A-V nodal and intranodal reentry are the responsible mechanisms in this reciprocating tachycardia. We conclude that the short P-R interval was due to intranodal reentry through the dual A-V nodal pathways. To our knowledge, a case of Lown-Ganong-Levine syndrome with apical hypertrophic cardiomyopathy has not been previously described in the literature.

Cardiac Catheterization↗
PubMed1988

[Prediction of avascular necrosis in the femoral head following fracture dislocation--using the electrochemically generated hydrogen clearance method].

In order to predict necrosis of the femoral head following fracture-dislocation, the blood flow in the femoral heads in twenty-five hips was measured immediately after reduction and three, six, nine and twelve months thereafter. Twenty hips were followed up for more than one year (average 26.3 months) radiographically. Seven out of twenty hips had very low blood flow in the weight bearing areas three months after reduction. Five of seven had very low blood flow six and nine months after reduction and resulted in necrosis which was determined radiographically. The other two of seven recovered the blood flow and have not resulted in necrosis. Thirteen hips with normal blood flow three months after reduction also did not undergo necrosis. It is possible to predict the incidence of necrosis after fracture-dislocation by measuring the blood flow of the femoral head with the electrochemically generated hydrogen clearance method.

Femoral Fractures↗