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Biomedical subjects

T Eguchi

Publications and source records attributed to T Eguchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Novel substrate specificity of designer 3-isopropylmalate dehydrogenase derived from Thermus thermophilus HB8.

Redesigning of an enzyme for a new catalytic reaction and modified substrate specificity was exploited with 3-isopropylmalate dehydrogenase (IPMDH). Point-mutation on Gly-89, which is not in the catalytic site but near it, was done by changing it to Ala, Ser, Val, and Pro, and all the mutations changed the substrate specificity. The mutant enzymes showed higher catalytic efficiency (kcat/Km) than the native IPMDH when malate was used as a substrate instead of 3-isopropylmalate. More interestingly, an additional insertion of Gly between Gly-89 and Leu-90 significantly altered the substrate-specificity, although the overall catalytic activity was decreased. Particularly, this mutant turned out to efficiently accept D-lactic acid, which was not accepted as a substrate by wild-type IPMDH at all. These results demonstrate the opportunity for creating nove,enzymes by modification of amino acid residues that do not directly participate in catalysis, or by insertion of additional residues.

3-Isopropylmalate Dehydrogenase↗
PubMed2001

Hypoglycemia associated with the production of insulin-like growth factor II in adrenocortical carcinoma.

A 78-year-old woman was hospitalized for congestive heart failure and repeated hypoglycemic attacks. The laboratory data showed a serum insulin level within the normal range and an increased level of serum insulin-like growth factor (IGF) II. Abdominal ultrasonogram and computed tomography scan revealed a huge mass lying above the left kidney. She was diagnosed as having an adrenocortical carcinoma. After the removal of the tumor, the plasma glucose level and the serum level of IGF-II were normalized. The tumor cells stained positively for IGF-II immunohistochemically. These findings suggested that the hypoglycemia was due to IGF-II produced by the adrenocortical carcinoma.

Adrenal Cortex Neoplasms↗
PubMed2001

Spontaneous thoracic spinal cord herniation--case report.

A 54-year-old female presented with spontaneous thoracic spinal cord herniation manifesting as chronic progressive motor weakness in both legs. Spastic paraparesis (4/5) and pathological reflexes such as ankle clonus were noted. She also had mild bladder dysfunction but no bowel dysfunction. She had no sensory disturbance, including tactile and pinprick sense. Magnetic resonance (MR) imaging revealed that the atrophic spinal cord was displaced into the ventral extradural space at the T4-5 intervertebral level with markedly dilated dorsal subarachnoid space. Computed tomography obtained after myelography showed no evidence of intradural spinal arachnoid cyst. She underwent surgical repair of the spinal cord herniation via laminectomy, and spinal cord herniation through the ventral dural defect was confirmed. Postoperative MR imaging revealed improvement of the spinal cord herniation, but her symptoms were not improved. Spontaneous spinal cord herniation is a rare cause of chronic myelopathy, occurring in the upper and mid-thoracic levels, and the spinal cord is usually herniated into the ventral extradural space. Early differential diagnosis from intradural spinal arachnoid cysts is important for a satisfactory outcome.

Female↗
PubMed2001

Isolation and structure elucidation of vicenistatin M, and importance of the vicenisamine aminosugar for exerting cytotoxicity of vicenistatin.

A new analogue of vicenistatin was isolated from the producing strain Streptomyces sp. HC-34. A characteristic of the elucidated structure involved the existence of a neutral sugar mycarose instead of an aminosugar vicenisamine of vicenistatin. The absolute stereochemistry of the new analogue (named as vicenistatin M) was determined by the synthesis of D-mycarose and of vicenistatin M itself. Biological testing of vicenistatin M suggested the importance of vicenisamine for exerting the cytotoxicity of vicenistatin.

Amino Sugars↗
PubMed2001

[Curative resection of advanced gastric cancer responding to preoperative chemotherapy--a case report].

A 56-year-old male was admitted for treatment of advanced gastric cancer. The patient was diagnosed as having an unresectable advanced gastric cancer because cancer cells had invaded the pancreas head and there were metastatic lymph nodes. The patient underwent preoperative chemotherapy (FLEP: intra-arterial infusion of CDDP, ETP and intravenous infusion of 5-FU, LV). The primary tumor and metastatic lymph nodes were reduced by three course of chemotherapy. The patient underwent curative resection and survived without recurrence for 14 months after operation. Preoperative chemotherapy using FLEP was performed in 15 patients with unresectable primary advanced gastric cancer. This therapy resulted in significantly higher survival times. In conclusion, FLEP has been shown to be effective for unresectable advanced gastric cancer.

Adenocarcinoma↗
PubMed2001

[FLEP therapy for advanced and recurrent gastric cancer].

The FLEP regimen (5-FU, LV, ETP and CDDP) is a combination chemotherapy administered regionally and systemically for the control of both local and disseminated disease in intra- and extra-abdominal regions in patients with advanced and recurrent gastric cancer. Sixty-one patients with advanced and recurrent gastric cancer were entered into this study. The treatment regimen consisted of 5-FU at 370 mg/m2 (days 1 to 5, i.v. 24 h); LV at a dose of 30 mg (days 1 to 5, i.v. bolus); and ETP and CDDP each at 70 mg/m2 (days 7 and 21, ia 2 h). This regimen was repeated every four weeks. The overall response rate was 36.1% (22/61) and the 50% and median survival times were 10.23 and 11.80 months, respectively. The adverse events were Grade 3/4 leukocytopenia (18.0%), Grade 3/4 thrombocytopenia (4.9%), Grade 3 nausea and/or vomiting (3.3%) and Grade 3 stomatitis (1.6%). Of the 17 NAC patients, the six curability B patients showed a statistically higher survival rate than the curability C and unresected patients. Based on the encouraging response rate and the improvement in prognosis, we recommend the FLEP regimen for patients with primary gastric cancer. Neoadjuvant chemotherapy using the FLEP regimen should be performed with curative resection as an objective.

Adult↗
PubMed2000

Application of acid-treated yeast cell wall (AYC) as a pharmaceutical additive. II: effects of curing on the medicine release from AYC-coated tablets.

Acid-treated yeast cell wall (AYC) was newly prepared by acidifying brewers' yeast cell wall. Core tablets containing 3% of acetaminophen (AAP) were coated with the AYC aqueous dispersion containing 5% (w/v) of AYC and 0.35% (w/v) of glycerol. The curing of AYC-coated tablets was performed at various curing periods of time and temperatures. The effects of curing on AAP release from AYC-coated tablets, the weight and thickness of the coated layer of AYC and the water sorption into the AYC-coated tablets were studied. The tensile strength and pore size distribution of the AYC cast film were measured. In the case of 60, 80, or 100 degrees C curing, AAP release from AYC-coated tablets showed a sigmoidal release profile with an initial lag time. The duration of the lag time increased with the increasing curing time and temperature, though the release rate after the lag time hardly changed. At 120 degrees C curing, the release rate after the lag time decreased with the increasing curing time and a sustained release was observed. The weight and thickness of the AYC-coated layer and the water sorption rate into AYC-coated tablets decreased with the increasing curing time and temperature. The tensile strength of the AYC cast film increased with increasing the curing temperature, particularly at 120 degrees C curing. It is considered that the water was evaporated from the AYC-coated layer and the adhesion force between AYC particles increased during curing, making the structure of the AYC-coated layer densely firm. The changes in the duration of lag time and the release rate may be due to changes in the structure of the AYC-coated layer caused by curing. These results show that it is feasible to control the lag time and the release rate of AAP from AYC-coated tablets by varying the curing time and temperature.

Acetaminophen↗
PubMed2000

Characterization of a mouse ctgf 3'-UTR segment that mediates repressive regulation of gene expression.

We isolated a small segment of the 3'-untranslated region (3'-UTR) in the mouse connective tissue growth factor (ctgf/fisp12) gene and evaluated its functionality. Comparison of the nucleotide sequences of human and mouse ctgf 3'-UTRs revealed a conserved small segment of 91 bases. The corresponding segments of the 3'-UTRs shared as much as 82.4% homology, whereas the overall homology between the 3'-UTRs was 71.8%. To study the functionality of the conserved segment, the corresponding region of mouse ctgf cDNA was amplified from NIH3T3 cells. When it was fused downstream of a marker gene, it showed remarkable repressive effects on gene expression. The repressive effect of the sense form was more prominent than that of the antisense form. Computer analyses of these sequence predicted stable secondary structures, suggesting that they act at the RNA level. The predicted structures of the sense and antisense forms appeared to be slightly different, which is consistent with the difference in repressive function. These findings defined the conserved small element in the mouse ctgf gene as a potent negative regulator of gene expression, which may act at a posttranscriptional level.

3' Untranslated Regions↗
PubMed2000

Identification of an RNA element that confers post-transcriptional repression of connective tissue growth factor/hypertrophic chondrocyte specific 24 (ctgf/hcs24) gene: similarities to retroviral RNA-protein interactions.

The repressive effect of the 3'-untranslated region (3'-UTR) in human connective tissue growth factor/ hypertrophic chondrocyte specific 24 (ctgf/hcs24) mRNA on gene expression had been demonstrated in our previous study. Here, we identified a minimal RNA element in the 3'-UTR, which acts as a cis-acting element of structure-anchored repression (CAESAR). Deletion analyses of the 3'-UTR led us to minimize the element of 84 bases at the junction of the coding region and the 3'-UTR. The minimized RNA segment is predicted, and actually capable of forming a stable secondary structure in vitro. Mutational analyses disclosed a significant relationship between the predicted structure and repressive effect. The utility of CAESAR as a post-transcriptional regulatory element was represented by the fact that steady-state mRNA levels were not affected by CAESAR linked in cis, while protein levels from such a chimeric gene were markedly reduced. Of note, the CAESAR sequence exerted no effect, when it was placed upstream of the promoter. Finally, RNA gel electromobility-shift analyses demonstrated a nuclear factor that interacts with the folded CAESAR. Taken together, it was uncovered that CAESAR of ctgf is a novel post-transcriptional structured RNA regulatory element, probably acting through direct interactions with a nuclear factor as observed in retroviral RNA elements with certain proteins.

3' Untranslated Regions↗
PubMed2000

Giant vesicles from 72-membered macrocyclic archaeal phospholipid analogues: initiation of vesicle formation by molecular recognition between membrane components

Stereochemically pure archeal acyclic bola-amphiphilic diphosphates 4 and 5, with the basic structure of the phospholipids found in Sulfolobus, have been synthesized for the first time. The self-assembly properties have been compared with those of the nearly identical 72-membered macrocyclic tetraether phosphates 3a and 3b, analogues of the major phospholipid components of Sulfolobus, Thermoplasma, and methanogenic Archea, which were also synthesized. Phase contrast and fluorescence microscopies have shown that the dipolar lipids 1 and 2 spontaneously formed vesicles. Whereas the macrocyclic dipolar phosphates 3 spontaneously formed vesicles (phase contrast and fluorescence microscopies), the bolaform phosphate 4 gave only a lamellar structure (synchrotron diffraction pattern: repeat distance of about 4.25 nm but with only a few layers). However, upon addition of the unphosphorylated precursors phytanol, phytol, or geranylgeraniol to the acyclic lipids 4 and 5, giant vesicles were rapidly formed. Addition of n-hexadecanol or cholesterol did not lead to vesicle formation. Therefore it was concluded that this vesicle formation occurs only when the added molecule is closely compatible with the constituents of the lipid layer and can be inserted into the double layer. A slight mismatch (cholesterol or n-hexadecanol/polyprenyl chains) is therefore enough to block the insertion process presumably required for vesicle formation.

Journal Article↗
PubMed2000

Application of acid-treated yeast cell wall (AYC) as a pharmaceutical additive I. AYC as a novel coating material.

Acid-treated yeast cell wall (AYC) was newly prepared by acidifying the cell wall of brewer's yeast and the potential to use AYC as a novel coating material was studied. AYC had an oval shape with the diameter of several microm. The rheogram of AYC aqueous dispersion showed the plastic fluid property that is generally observed in the suspension. Core tablets containing 3% of acetaminophen (AAP) were coated with the AYC aqueous dispersion containing 5% (w/v) of AYC and 0.35% (w/v) of glycerol at various coating percents. The AAP release profile from the AYC-coated tablets was studied by the JP13 paddle method using solutions at various pH. Tensile strength and permeability of oxygen and water vapor of AYC cast film were measured. The AAP release from the AYC-coated tablets showed sigmoidal release profile with an initial lag time and the duration of the lag time depended on the coating percent of AYC. The pH of the dissolution fluid or the storage at room temperature for 120 days had little affect on AAP release from the AYC-coated tablets. These results suggest that it is possible to control the start time of medicine release independent of the pH by coating of AYC, that is the time-controlled release. The AYC cast film showed a large tensile strength and an extremely small oxygen permeability coefficient and a sufficient level of water permeability coefficient in order to protect from moisture. These results present that AYC has the high utility as a novel aqueous coating material for DDS preparations.

Acetaminophen↗
PubMed2000

Membrane properties of archaeal macrocyclic diether phospholipids.

Several biophysical properties of four synthetic archaeal phospholipids [one polyprenyl macrocyclic lipid A and three polyprenyl double-chain lipids (B, C, D) bearing zero, one or four double bonds in each chain] were studied using differential scanning calorimetry, electron and optical microscopies, stopped-flow/light scattering and solid-state 2H-NMR techniques. These phospholipids gave a variety of self-organized structures in water, in particular vesicles and tubules. These assemblies change in response to simple thermal convection. Some specific membrane properties of these archaeal phospholipids were observed: They are in a liquid-crystalline state over a wide temperature range; the dynamics of their polyprenyl chains is higher than that of n-acyl chains; the water permeability of the membranes is lower than that of n-acyl phospholipid membranes. It was also found that macrocyclization remarkably improves the barrier properties to water and the membrane stability. This may be related to the adaptation of Methanococcus jannaschii to the extreme conditions of the deep-sea hydrothermal vents.

Cryoelectron Microscopy↗
PubMed2000

Galactose metabolites in blood from neonates with and without hypergalactosaemia detected by mass screening.

UNLABELLED: Concentrations of galactose (Gal) in plasma and galactose metabolites in red blood cells (RBC) were determined in 18 normal neonates and 249 others with hypergalactosaemia according to the Paigen method. Normal neonatal values for plasma Gal, RBC galactose-1-phosphate (Gal-1-P), RBC uridine diphosphate glucose (UDP-Glc), and RBC uridine diphosphate galactose (UDP-Gal) were 0.96 +/- 0.71 mg/dl, 1.69 +/- 1.45 mg/dl of packed RBC, 1.00 +/- 0.45 mg/dl of packed RBC, and 1.44 +/- 0.45 mg/dl of packed RBC, respectively. The UDP-Gal concentration was higher and the UDP-Glc concentration lower than previously reported in normal children. Of the 249 cases with excessive Gal in whole blood, 23 showed high Gal concentrations in plasma; among these, four portacaval shunts and one case of congenital biliary atresia were diagnosed. In subjects homozygous or heterozygous for UDP-Gal-4 epimerase deficiency, concentrations of UDP-Gal and Gal-1-P were elevated only in RBC, corresponding to restriction of the metabolic abnormality to these cells. Most cases of hypergalactosaemia detected by the Paigen method have large excesses of Gal-1-P in RBC. Although a specific diagnosis based solely on blood Gal metabolites is difficult, individual concentrations reflect underlying conditions to some extent. CONCLUSION: In neonates, uridine diphosphate galactose concentrations were higher and uridine diphosphate glucose concentrations were lower than previously reported paediatric values. Patients with high plasma galactose concentrations should be investigated by hepatic imaging.

Biliary Atresia↗
PubMed2000

Detection of aberrations of 17p and p53 gene in gastrointestinal cancers by dual (two-color) fluorescence in situ hybridization and GeneChip p53 assay.

We performed dual (two-color) fluorescence in situ hybridization (FISH) using direct fluorescent labeling probes for p53 and chromosome 17 in six gastrointestinal (3 stomach and 3 colon) cancers. In three of these (1 stomach and 2 colon) the interphase cell nuclei showed an imbalance of signals for the p53 and chromosome 17; that is, the p53 signal count was lower than the chromosome 17 signal count, indicating deletion of the p53 gene. Moreover, metaphase FISH analysis demonstrated that those nuclei actually had a chromosome 17 with deletion of the p53 gene. Interestingly, these three cases had an abnormal chromosome 17 copy number, that is, chromosome 17 aneusomy. Furthermore, to investigate the possibility of p53 mutation in tumors with an imbalance of signals for chromosome 17 and p53 per nucleus, we performed a GeneChip p53 assay which has recently been developed. GeneChip p53 assay demonstrated that a primary tumor sample from one colon cancer case had a heterozygous point mutation of CGT (Arg) to CAT (His) at codon 273 in exon 8. In addition, a sample of metastatic tumor in the liver from the same case revealed two heterozygous point mutations. One of them was the same mutation as that is the primary tumor; the other was GTG (Val) to GGG (Gly) at codon 217 in exon 6. In conclusion, we found that the combination of dual-color FISH and GeneChip p53 assay offered reliable results and important information concerning not only deletion of the p53 gene and chromosome 17 aneusomy but also p53 mutations. Using these techniques, we demonstrated that an imbalance of signals for chromosome 17 and p53 per nucleus, chromosome 17 aneusomy, and accumulation of p53 mutations had occurred during carcinogenesis and development of gastrointestinal cancers.

Centromere↗
PubMed2000

Production and structural analysis of PP-V, a homologue of monascorubramine, produced by a new isolate of Penicillium sp.

A fungal strain newly isolated from soil has been found to produce a violet water-soluble pigment (PP-V) in high quantity when cultured in a medium consisting of soluble starch and citrate buffer. Glucose repressed the production of this pigment. PP-V has the molecular formula C23H25NO6 revealed by HR-FAB mass spectroscopy and has been shown to be composed of an isoquinoline skeleton, a n-octanoyl group, and a 2-propenoic acid group by NMR. In conclusion, PP-V is a novel compound, 3-(9a-methyl-3-octanoyl-2,9-dioxo-2,7,9,9a-tetrahydro-furo[3,2-g]isoquinolin-6-yl)acrylic acid; a homologue of monascorubramine in which the 1-propenyl group is converted to a 2-propenoic acid group.

Journal Article↗
PubMed2000

Amino acid sequences of hemoglobin from guinea fowl (Numida meleagri) and California quail (Lophortyx californica) with phylogenetic analysis of major groups of Galliformes.

We determined the complete amino acid sequences of the hemoglobin of two species, guinea fowl and California quail, in Galliformes from intact globin chain and chemical cleavage fragments in order to analyze the molecular evolution of hemoglobin for the classification of Galliformes. Galliformes have two types of hemoglobin components, HbA and HbD, which consist of identical beta chain and different alpha chains. The sequences are similar to globin chains of Galliformes reported previously. These sequences were compared with those of other Galliformes (Phasianidae, Meleagrididae) using duck and goshawk as out-groups. The phylogenetic tree of major groups of Galliformes based on hemoglobin was similar to the tree model produced based on the amino acid sequence of lysozyme c.

Amino Acid Sequence↗
PubMed2000

Delay of liver maturation as a cause of transient neonatal galactosemia.

BACKGROUND: Because a large amount of serum alpha-fetoprotein (alpha-FP) is synthesized in the liver of the fetus or premature newborn, high concentrations or delayed degradation of serum alpha-FP during the neonatal period may reflect hepatic immaturity. METHODS: In order to evaluate the relationship between transient neonatal galactosemia and delay of liver maturation, the concentration and half-life of serum alpha-FP during the neonatal period were measured in patients with transient galactosemia and in normal neonates. RESULTS: No significant differences were observed in the serum concentration of alpha-FP between normal and galactosemic patients less than 1 month of age. However, the half-life of serum alpha-FP was significantly longer in galactosemic patients between 15 and 60 days of age compared with age-matched normal neonates. CONCLUSION: Based on these results, we hypothesize that delay of liver maturation during the neonatal period, especially during the first 2 months after birth, can be a cause of transient neonatal galactosemia.

Galactose↗