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Biomedical subjects

Y Takada

Publications and source records attributed to Y Takada.

At least 307 records · Page 17Linked to original sources
PubMed1995

Amino acids, serotonin, and 5-hydroxyindoleacetic acid following foot shock in rats.

Concentrations of tryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) in brain and plasma, as well as plasma amino acid composition, were measured after 1-h foot shock. Stress induced a rise in both plasma and brain 5-HIAA, whereas 5-HT concentration was found to be increased only in plasma. A prominent rise in brain tryptophan was observed, whereas in plasma, foot shock caused a significant increase only in tryptophan level. Concentrations of other amino acids were found to be either decreased or unchanged. Ratio of tryptophan to the other long-chain neutral amino acids increased significantly following foot shock. It is possible that stress-related changes in 5-HT turnover are due to increased plasma tryptophan, in turn causing a rise in brain tryprophan, necessary to cope with enhanced 5-HT metabolism, reflected as a rise in 5-HIAA levels.

Amino Acids↗
PubMed1995

Fractures of the floor of the anterior cranial fossa.

We treated 28 patients with anterior cranial fossa floor fractures. Computed tomography (CT) scans adjusted to bone density disclosed three fracture types: (1) penetrating fractures through the orbita or ethmoid sinus; (2) simple or multiple linear fractures; and (3) extensive comminuted anterior cranial fossa floor fractures. Thirteen patients underwent emergent surgery for treatment of open depressed fractures (most common in type 3 fractures), for foreign bodies (in type 1 fractures), and for optic canal decompression. Large dural lacerations were always present in patients with type 3 fractures, and repairs were made with dural substitutes. Only one patient developed postoperative cerebrospinal fluid leakage. Nine (32%) of the patients in our series had visual involvement, but visual acuity recovered or improved in six patients. Our study shows that initial neuroradiologic evaluation with CT scans is important in patients with frontobasal fractures, and that secure dural repair during primary operation helps prevent cerebrospinal fluid leakage.

Adolescent↗
PubMed1995

Differential expression in Escherichia coli of the Vibrio sp. strain ABE-1 icdI and icdII genes encoding structurally different isocitrate dehydrogenase isozymes.

The expression of two structurally different isocitrate dehydrogenase isozymes of Vibrio sp. strain ABE-1 in Escherichia coli was examined. At a low temperature (15 degrees C), a thermolabile and monomeric type isozyme (IDH-II), which is quite different in amino acid sequence from the E. coli isocitrate dehydrogenase, was expressed and conferred glutamate prototrophic ability on an E. coli mutant defective in isocitrate dehydrogenase. The ability of IDH-II to confer restoration of the E. coli mutant to glutamate prototrophy was similar to that of IDH-I, which is a dimeric enzyme homologous to the E. coli isocitrate dehydrogenase. At a high temperature (37 degrees C), no functional IDH-II was expressed. Transcription of icdI and icdII genes, which encode IDH-I and IDH-II, respectively, was regulated differently by different environmental conditions. The level of icdII mRNA was increased by lowering the growth temperature for E. coli transformants, while the level of icdI mRNA was increased when E. coli transformants were cultured in acetate minimal medium. Similar patterns of transcriptional regulation of the two icd gene were observed also in Vibrio sp. strain ABE-1. However, activity of isocitrate dehydrogenase kinase, which can phosphorylate IDH-I and consequently inactivate the enzymatic activity, was detected in cell lysates of E. coli but not of Vibrio sp. strain ABE-1.

Acetates↗
PubMed1995

Effect of growth hormone on hepatic energy metabolism in normal rabbit liver.

Growth hormone (GH), which is well known as an anabolic agent in systemic protein metabolism but has catabolic effects on the carbohydrate metabolism in the liver, was administered to normal rabbit to investigate its effects on the hepatic energy metabolism. The changes in arterial ketone body ratio (AKBR: acetoacetate/3-hydroxybutyrate), which reflects the hepatic mitochondrial redox state ([NAD+]/[NADH]), after GH injection was studied as an indicator of the hepatic energy metabolism. GH was administered to normal rabbit at the doses of 50 micrograms/kg (GH-50 group), 100 micrograms/kg (GH-100 group) and 200 micrograms/kg (GH-200 group) by intravenous bolus injection. In the GH-50, GH-100 and GH-200 groups, AKBR decreased significantly from 1.40 +/- 0.09 to 0.94 +/- 0.05, from 1.19 +/- 0.11 to 0.83 +/- 0.14, and from 1.19 +/- 0.08 to 0.71 +/- 0.15 at 90 min, respectively. The energy charge of the liver decreased significantly 90 min after 200 micrograms/kg GH injection from 0.872 +/- 0.003 to 0.836 +/- 0.012 (p < 0.05). These results suggest that GH is associated with the deterioration of the hepatic energy metabolism, and that the administration of GH should be carefully weighed up in cases of damaged liver.

Animals↗
PubMed1995

Familial hypobetalipoproteinemia associated with hypothyroidism.

A 55-year-old Japanese woman with familial hypobetalipoproteinemia associated with hypothyroidism was admitted to the hospital because of orthopnea and congestive heart failure. Thyroid function testing revealed hypothyroidism, but she exhibited low levels of serum cholesterol (111 mg/dl) and apolipoprotein (apo) B (48.5 mg/dl). No abnormal bands were detected with gradient sodium dodecyl sulfate-polyacrylamide gel electrophoresis of very low density lipoprotein, low density lipoprotein and high density lipoprotein followed by immunoblotting with anti apo B polyclonal antibody. In this case, apo B structural abnormality could not be identified.

Female↗
PubMed1995

Production of the new antibiotic tetrahydrokalafungin by transformants of the kalafungin producer Streptomyces tanashiensis.

The new antibiotic tetrahydrokalafungin was produced by the transformants of kalafungin producing S. tanashiensis and kalafungin-nonproducing mutants carrying the recombinant plasmid pKU523. This plasmid consists of pKU501 (J. Antibiotics 44: 995 approximately 1005, 1991) which contains the gene cluster for kalafungin biosynthesis, and additional 5 kb stability region of SCP2*.

Anti-Bacterial Agents↗
PubMed1995

Structural elucidation of aculeximycin. III. Planar structure of aculeximycin, belonging to a new class of macrolide antibiotics.

The planar structure of aculeximycin (1) produced by Streptosporangium albidum has been determined by spectral methods and chemical degradations such as 1,8-diazabicyclo[5,4,0]undec-7-ene (DBU)-methanol reaction, ozonolysis, and periodative oxidation. The antibiotic consists of a 30-membered polyhydroxy lactone ring, an alpha, beta-unsaturated ester group, an intramolecular hemiketal, an oligosaccharide (aculexitriose), a neutral sugar and an amino sugar. The structure of aculeximycin is closely related to those of sporaviridins produced by Streptosporangium viridogriseum. We consider that aculeximycin and sporaviridins belong to a new class of macrolide antibiotics, which is different from the polyol macrolides produced by Streptomyces.

Acetylation↗
PubMed1995

[Expression of fibroblast growth factor receptor 1 in experimental choroidal neovascularization with in situ hybridization].

Fibroblast growth factor (FGF) is an important factor for neovascularization in vivo. In order to clarify the role of FGF in experimentally produced choroidal neovascularization, we demonstrated mRNA for FGF receptor 1 in situ hybridization. Krypton laser photocoagulation was applied to the posterior retina of colored rats to produce choroidal neovascularization experimentally. These eyes were removed at several different intervals after photocoagulation. Chorioretinal section were used for in situ hybridization. FGF receptor 1 cDNA fragment was used to make antisense and sense probes for in situ hybridization. In normal chorioretinal tissue, staining indicating the existence of FGF receptor 1 mRNA was seen in the ganglion cell layer and inner nuclear layer. After the photocoagulation, the staining was seen in the retinal pigment epithelial cells, melanocytes in the choroid, and choroidal blood vessel wall in the photocoagulated lesions. FGF receptor 1 mRNA was expressed through the development of choroidal neovascularization, and it appears that FGF is necessary for development of choroidal neovascularization. Previous workers showed that the capillary endothelial cells and retinal pigment epithelial cells produce basic FGF in vitro. It seems that FGF effects those cells in an autocrine or paracrine manner in vivo.

Animals↗
PubMed1995

Population frequency of apolipoprotein E5 (Glu3-->Lys) and E7 (Glu244-->Lys, Glu245-->Lys) variants in western Japan.

Apolipoprotein (apo) E modulates the catabolism of chylomicrons and of very low density lipoprotein remnants. It has three major isoforms (apo E2, E3, E4) and some rare variants. To detect the variants of apo E, blood specimens from 1269 Japanese subjects were analyzed using isoelectric focusing with immunoblotting. The E5 and E7 variants were identified by IEF in 2 and 18 subjects, respectively. Both E5 (Glu3-->Lys) carriers were confirmed by PCR-mediated site-directed mutagenesis, and all E7 (Glu244-->Lys, Glu245-->Lys) carriers were confirmed by the amplification refractory mutation system. The relative frequencies of the epsilon 5 and epsilon 7 alleles were 0.001 and 0.007, respectively. High concentrations of total cholesterol (> 220 mg/dl) were detected in five of the subjects expressing apo E7 and one subject expressing apo E5, and eight subjects heterozygous for apo E7 showed elevated plasma triglyceride concentrations (> 150 mg/dl). In 621 healthy subjects, the mean triglyceride concentration in subjects with apo E7/3 appeared to be higher than in those with apo E3/3, but the difference was not statistically significant.

Adolescent↗
PubMed1995

[Subclassification, molecular structure, function and ligand in integrin superfamily].

Integrins are the major family of cell surface receptors that mediate adhesion to the extracellular matrix and sometimes cell-cell adhesive interactions. These integrin-mediated adhesive interactions are involved in the regulation of many cellular functions, including embryonic development, tumor cell growth and metastasis, programmed cell death, hemostasis, inflammation, immune reaction, bone reabsorption, etc. Integrins are composed of alpha and beta transmembrane subunits selected from among 16 alpha and 8 beta subunits that heterodimerize to produce more than 20 different receptors which bind specific ligands. Ligand binding sites have been clarified by chimera integrin protein in some integrins. Integrins link to intracellular cytoskeletal complexes and bundles of actin filaments. There have been many reports about intracellular signaling pathways activated by integrin-ligand interactions.

Humans↗
PubMed1995

[Analysis of the mechanism of tumor metastasis by the transfection of integrin cDNA].

Integrin plays an important role in tumor metastasis through its interaction with extracellular matrix and endothelial cell. We have examined the role of each integrin in tumor metastasis by using transfection of integrin cDNA into various cells. Transfection of integrin alpha 2 subunit into RD cells, human rhabdomyosarcoma cells which do not express integrin alpha 2 beta 1, potentiated the frequency of metastases in various organs; lung, bone, adrenal gland, lymph node. alpha 4-transfectant of Chinese hamster ovary (CHO) cells, which do not have alpha 4 beta 1 on the cell surface, metastasized to bone through its interaction with VCAM-1 in the bone marrow stroma cells. On the other hand, alpha 5-transfectant of CHO cells was much less tumorgenic than parent CHO cells. These data suggest integrin influence tumor metastasis sometimes favorably and sometimes unfavorably according to the activity and the balance of various integrins.

Animals↗
PubMed1995

Analysis of functional abnormalities uncovered during preoperative evaluation of donor candidates for living-related liver transplantation.

Functional abnormalities of the liver uncovered during preoperative routine evaluation were analyzed in 109 donor candidates for 100 cases of living-related liver transplantation (LRLT) performed during the period from June, 1990 to May, 1994 at the Second Department of Surgery, Kyoto University Hospital. High serum transaminase (GOT, GPT) levels were noted in 10 (9.2%) cases among 109 candidates, high alkaline phosphatase in 4 (3.7%), hyperbilirubinemia in 3 (2.8%), anemia in 3 and high choline esterase in 3 cases. Positive hepatitis C antibody (HCV) was also noted in 1 case. Fatty liver was detected in 10 (9.2%) cases, cholecystitis in 2 cases, 1 case each of cyst and calcification in the liver by diagnostic imaging (ultra sonograph and/or computed tomography). These abnormalities of the liver necessitated replacing the initial candidate with the other parent in 9 cases, including 1 case without any functional abnormality whose graft liver was too large to fit the recipient abdominal cavity. There were 14 cases of ABO blood type incompatible combination. Switching the initial candidate due to these abnormalities mentioned above resulted in incompatible combinations in 4 of these 14 cases. Although the advantages of the LRLT are the superior viability of the donor graft and the genetic histocompatibility between recipient and donor, to optimize the advantage of LRLT, all donor candidates should be strongly advised to make every effort preoperatively to improve their physical condition in preparation for the LRLT protocol, since many of these abnormalities are typically reversible.

ABO Blood-Group System↗
PubMed1995

[A late phase-II trial comparing KW-2307 with vindesine in non-small cell lung cancer (1). Lung cancer section in KW-2307 Study Group].

A multicenter cooperative study was performed to compare KW-2307 (KW), a novel vinca alkaloid (VA) derivative, and vindesine (VDS), with respect to tumor response and toxicity in patients (pts) with non-small cell lung cancer. In the former part of the trial, pts received monotherapy with KW 25 mg/m2 or VDS 3 mg/m2. Pts refractory to treatment with KW or VDS were crossed over to treatment with VDS (3 mg/m2/W x 3) or KW (20 mg/m2/W x 3), respectively, in combination with cisplatin (CDDP) 80 mg/m2. Both drugs were administered in 4 courses or more once weekly by intravenous bolus injection in monotherapy. In the subsequent combination therapy, non-responders were treated with CDDP on day 1 and KW or VDS on day 1, 8 and 15 with a course of 28 days, and treatment was given in 2 courses or more in principle. According to the method of O'Brien/Fleming, comparison of tumor response between the 2 treatment groups in the 2nd stage was performed in 154 cases. The response rate of KW group (29.4%, 22/75) was significantly better than that of VDS group (9.3%, 7/75). The main adverse effect in both groups was leukopenia (neutropenia), and no significant difference was observed between the incidence in each group. Among other adverse effects, increased GOT, fever and phlebitis were slightly more often found in KW group, and alopecia and paresthesia a little more in the VDS group. In the later part of combination therapy with CD DP, the KW group achieved PR in 10 of 34 pts (29.4%), and no response was observed in the VDS group (28 pts).

Adenocarcinoma↗
PubMed1995

Two novel point mutations in the lecithin:cholesterol acyltransferase (LCAT) gene resulting in LCAT deficiency: LCAT (G873 deletion) and LCAT (Gly344-->Ser).

We investigated the genetic defects in two patients with familial lecithin:cholesterol acyltransferase (LCAT) deficiency. Their clinical manifestations including corneal opacities, anemia, proteinuria, and hypoalphalipoproteinemia were identical for familial LCAT deficiency. Their LCAT activities and the cholesterol esterification rate (CER) were nearly zero, and their LCAT masses were below 10% of normal control values. Sequence analysis of the amplified DNA of case 1 revealed one base deletion of G at base 873 (first position of Val264) in exon 6, leading to a premature termination by frameshift. Sequence analysis of amplified DNA of case 2 revealed a single G to A converting Gly (GGT) to Ser (AGT) substitution at residue 344. When COS-1 cells were transfected with these mutants, LCAT activity in the medium was nearly zero, and the LCAT mass was undetectable (< 0.01 microgram/ml). In contrast, LCAT activity in the medium of COS-1 cells, transfected with wild-type LCAT, was 1.7 nmol/h per ml and the LCAT mass was 0.09 micrograms/ml. The LCAT mass in the cell lysates of the mutants was less than 12% of control for case 1 and 18% of control for case 2. Northern blot analysis of the mRNA of COS-1 cells transfected with the mutants showed the same amounts of LCAT mRNA as compared with wild-type LCAT. Biosynthesis of mutant LCATs was analyzed by pulse-chase and immunocytochemistry in transfected baby hamster kidney cells. SDS-PAGE/fluorography demonstrated that wild-type LCAT was synthesized as a high-mannose type of 56 kDa, which was very slowly converted to a mature form of 67 kDa and was secreted into the media. In contrast to the wild-type LCAT, the mutant precursors were not processed into the mature form but slowly degraded along with chase times. On steady and continuous labeling in the case of wild-type LCAT, the mature 67 kDa form was observed in both the cell lysate and media, whereas no mature form was detected in the cell lysates and media which were transfected mutant LCATs. These data suggest that the mutant LCATs are actually synthesized in an amount comparable to that of wild-type, but they are slowly degraded without being processed into the mature form. The immunocytochemistry revealed that mutant LCATs were mainly retained in the endoplasmic reticulum. These data suggest that these two mutations may disrupt the mutant LCATs' transport from the endoplasmic reticulum into Golgi apparatus, resulting in LCAT deficiency.

Adult↗