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Biomedical subjects

T Ishida

Publications and source records attributed to T Ishida.

At least 451 records · Page 25Linked to original sources
PubMed1997

[CT guided percutaneous microwave tumor coagulation therapy for local recurrence of rectal cancer].

PURPOSE: To evaluate the usefulness of the CT guided percutaneous microwave tumor coagulation (PMTC) therapy for local recurrence of rectal cancer. MATERIALS AND METHODS: The CT guided PMTC was performed for two patients with local recurrence of rectal cancer. Maximum axial diameter of the tumor was 30 mm on CT images. With patients in the prone position on the CT table, a 14-gauge needle-electrode was used to penetrate the tumor under epidural and local anesthesia. PMTC was performed with an output of 60 watts for 60 seconds at a time. Effects of the PMTC were evaluated by CT images obtained three months after the therapy. RESULTS: In both cases, there was no evidence of tumor growth on the CT images. Clinical symptoms disappeared soon after the therapy, and no major complication was observed. CONCLUSION: The CT guided PMTC therapy was useful for local recurrence of rectal cancer.

Aged↗
PubMed1997

[Lactic acidosis].

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Acidosis, Lactic↗
PubMed1997

[Blood grouping].

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ABO Blood-Group System↗
PubMed1997

Functional evaluation of flail hip joint after periacetabular resection of the pelvis.

Five patients subjected to flail hip joint after resection of primary bone tumor of the pelvis involving acetabular region were examined with respect to function. When a thick portion of the supraacetabular pelvic neck was left in place, the operated legs functioned well regardless of whether the head of the femur was placed anterior or posterior to the iliac wing. In a patient who had only a thin portion of the iliac wing left in place and in those who underwent total excision of the ilium or hemiresection of the pelvis, the function of operated legs was poorer than with a thick portion of the supraacetabular pelvic neck left in place, but still more than 50% of leg function remained. Although flail hip joint results in a larger leg-length discrepancy than do other techniques, it enables favorable healing of the operative wound. Therefore, this method should be considered for women or sedentary patients with primary bone tumor of the pelvis involving acetabular region.

Acetabulum↗
PubMed1996

Mutation of the cysteine residues in human initiation factor 4E: effects on mRNA cap binding ability.

To investigate the role of four Cys residues of eukaryotic initiation factor (eIF)-4E in the recognition of the mRNA cap structure, single, double and quadruple mutant genes which encoded the Ala residues in the place of the respective Cys residues were prepared using a synthetic human eIF-4E gene by the site-directed mutagenesis, and were expressed in E. coli with the same way as the wild type. The cap binding abilities of respective mutated eIF-4Es were compared with that of the wild-type by m7GTP affinity chromatography. The results suggest that, although all four of Cys residues participate in the recognition of the mRNA cap structure, they contribute indirectly to the stabilization of overall tertiary structure, especially of the cap binding pocket, rather than by direct interaction. A comparison among the cap binding abilities of single, double and quadruple mutants indicated no existence of internal disulfide bonds in eIF-4E.

Escherichia coli↗
PubMed1996

Identification of TRAF6, a novel tumor necrosis factor receptor-associated factor protein that mediates signaling from an amino-terminal domain of the CD40 cytoplasmic region.

CD40 signalings play crucial roles in B-cell function. To identify molecules which transduce CD40 signalings, we have utilized the yeast two-hybrid system to clone cDNAs encoding proteins that bind the cytoplasmic tail of CD40. A cDNA encoding a putative signal transducer, designated TRAF6, has been molecularly cloned. TRAF6 has a tumor necrosis factor receptor (TNFR)-associated factor (TRAF) domain in its carboxyl terminus and has a RING finger domain, a cluster of zinc fingers and a coiled-coil domain, which are also present in other TRAF family proteins. TRAF6 does not associate with the cytoplasmic tails of TNFR2, CD30, lymphotoxin-beta receptor, and LMP1 of Epstein-Barr virus. Deletion analysis showed that residues 246-269 of CD40 which are required for its association with TRAF2, TRAF3, and TRAF5 are dispensable for its interaction with TRAF6, whereas residues 230-245 were required. Overexpression of TRAF6 activates transcription factor NFkappaB, and its TRAF-C domain suppresses NFkappaB activation triggered by CD40 lacking residues 246-277. These results suggest that TRAF6 could mediate the CD40 signal that is transduced by the amino-terminal domain (230-245) of the CD40 cytoplasmic region and appears to be independent of other known TRAF family proteins.

Amino Acid Sequence↗
PubMed1996

A natural variant of bovine dopamine beta-monooxygenase with phenylalanine as residue 208: purification and characterization of the variant homo- and heterotetramers of (F208)4 and (F208)2(L208)2.

Bovine dopamine beta-monooxygenase was purified from each of 18 individual adrenal glands by the method we have developed for the rapid purification of the enzyme from a single adrenal gland. Differential peptide mapping of the 18 enzyme preparations following fluorescence labeling of their cysteine residues revealed the presence of a novel variant with Phe as residue 208 in 14 adrenal glands; seven of them were homozygous for the variant allele and the remaining seven heterozygous. The variant enzyme was a tetramer and exhibited kinetic and structural properties similar to those of the wild-type tetramer (L208)4. These results indicate an allelic polymorphism and codominant expression of the two alleles of the enzyme gene.

Adrenal Medulla↗
PubMed1996

A variant CD30 protein lacking extracellular and transmembrane domains is induced in HL-60 by tetradecanoylphorbol acetate and is expressed in alveolar macrophages.

We identified and cloned cDNAs for two novel CD30 mRNAs of 2.3 kb that are induced by 12-O-tetradecanoylphorbol 13-acetate (TPA) in the human myeloid leukemia cell line HL-60. These transcripts were transcribed from the intronic region just upstream of the exon coding for the transmembrane domain of the CD30 protein. The shorter cDNA had a deletion of 54 nucleotides corresponding to the 3' region of the transmembrane domain of the CD30 and which was probably caused by alternative splicing. Translation of these transcripts appeared to start from the internal methionine codon at nucleotide position 289 that corresponds to that of 1612 in the CD30 cDNA, and encode a protein of 132 amino acid residues which corresponds exactly to the C-terminal cytoplasmic domain of CD30 protein. The calculated molecular mass of this variant CD30 (CD30v) protein was 14,087. Thus, the predicted CD30v protein retains most of the cytoplasmic region, but lacks the extracellular and transmembrane domains. Northern blots detected the expression of CD30v transcripts only in the lung and the TPA-stimulated HL-60 cell line. Translation of this mRNA in vitro produced a protein of 25 kD. Immunoblotting analysis with HCD30C1, a rabbit polyclonal antibody raised against the cytoplasmic domain of CD30 protein, detected proteins with an apparent Mr 25 kD expressed in TPA-stimulated HL-60 and COS-7 cells that were transfected with both types of CD30v cDNAs. Constitutive phosphorylation of the CD30v protein was demonstrated by in vitro labeling with [32P]. Immunohistochemical studies demonstrated CD30v protein was in alveolar macrophages. Cotransfection experiments using a kappa B-site-dependent reporter construct showed that CD30v can transactivate gene expression through activation of NF kappa B, as was noted on the authentic CD30 protein. Overexpression of the CD30v induced differentiation of HL-60 cells as evidenced by an increased NBT reduction activity. These observations provided new insights into the molecular heterogeneity and biological function of CD30 in myeloid cells.

Animals↗
PubMed1996

Hypersensitivity of NIH3T3 cells transformed by H-ras gene to DNA-topoisomerase-I inhibitors.

We examined the effects of the introduction of H-ras oncogene into murine cell line NIH3T3 on growth inhibition by topoisomerase-I (topo-I) inhibitors. The H-ras-transformed cells (pT22-3) showed approximately 12-fold increased sensitivity to a novel topo-I inhibitor, NB-506 [6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D-glucopyranosyl) -5H-indolo(2,3-a)pyrrolo(3,4-c) carbazole-5,7(6H)-dione], compared with the parental NIH3T3 cells. pT22-3 also showed increased sensitivity to other topo-I inhibitors such as camptothecin (approx. 3.0-fold) and CPT-11 (irinotecan, approx. 3.0-fold). Transformation of NIH3T3 by another oncogene (erbB2) did not affect their sensitivity to these topo-I inhibitors. pT22-3 had approximately 32-fold higher topo-I activity than NIH3T3, but the same topo-I content. In a cell-free system, topo-I activity was increased 2-fold by addition of the H-ras protein precipitated from pT22-3 cells. Topo I in the nuclear extract of pT22-3 was eluted easily by low concentrations of NaCl compared with that of NIH3T3, suggesting a qualitative change in pT22-3 topo 1. Increased phosphorylation of topo I was observed in pT22-3. Furthermore, NB-506 decreased the amount of the GTP-bound form of the H-ras product in pT22-3 cells. These results suggest that the high growth-inhibitory effect of a topo-I inhibitor, NB-506, on H-ras-transformed NIH3T3 cells is due to the H-ras-mediated signal-transduction pathway.

3T3 Cells↗
PubMed1996

Analysis of HLA-DM polymorphisms in sarcoidosis.

Sarcoidosis is a multisystemic granulomatous disorder showing significant increases in the HLA-DRB1*11, *12, *14 and *08 alleles in the Japanese population. To evaluate the role of polymorphism in the DMA and DMB genes in predisposition to sarcoidosis, seventy Japanese patients with sarcoidosis and 95 unrelated healthy controls were analyzed in the third exon polymorphisms within the DMA and DMB genes by the PCR-RFLP method. There were no differences in the distribution of DMA alleles between the patient and control groups. The frequency of DMB*0102 was higher (p < 0.05) and that of DMB*0101 was lower (p < 0.05) in the patients than in the healthy controls. However, this association and negative association could be explained by linkage disequilibrium with the disease-associated DRB1 alleles. The DMA and DMB genes do not primarily confer the susceptibility to sarcoidosis.

Adult↗
PubMed1996

Human group II phospholipase A2 in normal and diseased intervertebral discs.

We measured calcium-dependent phospholipase A2 (PLA2) activity and immunoreactive group II PLA2 levels of 54 normal discs obtained from cadavers and 73 disc samples surgically obtained from patients with spinal disorders, including intervertebral disc herniations, spondylosis, and spondylolisthesis. Both cadaveric and surgical disc specimens contained about two-fold greater PLA2 activity than the ileal mucosa, one of the richest sources of group II PLA2. Discs of middle-aged cases had significantly higher activity than those of younger and elder cases. In cadaveric normal discs, calcium-dependent PLA2 activity was significantly higher in females than in males. Annulus fibrosus and nucleus pulposus contained the same PLA2 levels. In diseased disc, herniated fragments that had extruded or protruded out of the discs possessed lower activity than other parts of discs in the intervertebral space. Immunoreactive group II PLA2 levels of intervertebral discs closely correlated with PLA2 enzymatic activity. We purified a PLA2 from human intervertebral disc to homogeneity to further identify the isozymic nature of discal PLA2. Its NH2-terminal amino acid sequences and molecular weight were identical to those of human group II PLA2. Immunohistochemical analysis using a monoclonal anti-group II PLA2 antibody showed that in both annulus fibrosus and nucleus pulposus chondrocytes contained intense group II PLA2 immunoreactivity in their cytoplasm, and that the matrix contained no substantial immunoreactivity. These results suggest that group II PLA2 in chondrocytes has important physiological roles in discal ordinary metabolism, maintaining discal homeostasis.

Adolescent↗
PubMed1996

Analysis of the mRNA cap-binding ability of human eukaryotic initiation factor-4E by use of recombinant wild-type and mutant forms.

In order to identify the amino acid residues necessary for the selective recognition of the mRNA cap structure by human eukaryotic initiation factor-4E (eIF-4E), which plays a central role in the first step of mRNA translation, we prepared recombinant wild-type and fourteen mutant forms and compared their cap-binding abilities by affinity chromatography. By the direct expression of a synthetic gene encoding human eIF-4E as the soluble form in Escherichia coli and the application on a 7-methylguanosine-5'-triphosphate-Sepharose 4B cap affinity column, pure recombinant eIF-4E was prepared; the optimum pH for the binding of the mRNA cap was 7.5. Among the amino acid residues conserved among various eIF-4E species, each of 14 functional residues was replaced with a nonpolar amino acid (alanine or leucine). All mutant eIF-4E genes, which were constructed by site-directed mutagenesis, were expressed in the same way as the wild type, and their cap-binding abilities were compared with that of the wild type. Consequently, all eight tryptophan residues. Glu103, and two histidine residues at positions 37 and 200 in human recombinant eIF-4E were suggested to be important for the recognition of the mRNA cap structure through direct interaction and/or indirect contributions. Indirect contributions included the construction of the overall protein structure, especially the cap-binding pocket.

Amino Acid Sequence↗
PubMed1996

Potentiation of the intracellular Ca2+ response to arginine vasopressin by increased cytosolic-free Mg2+ in rat vascular smooth muscle cells.

Although the inhibitory effects of extracellular Mg2+ on Ca2+ influx are well established, little is known about the effects of intracellular Mg2+ on Ca2+ handling. In the present study, the effects of cytosolic-free Mg2+ concentration in the physiological (submillimolar) range on Ca2+ handling were investigated after stimulation of rat vascular smooth muscle cells with arginine vasopressin. Cytosolic Mg2+ was manipulated by culturing cells in medium containing different Mg2+ concentrations. Peak cytosolic-free Ca2+ concentration responses to arginine vasopressin (1 mumol/1) were measured in the presence and absence of external Ca2+. The results suggest that an increase in cytosolic-free Mg2+ concentration increases both Ca2+ discharge from intracellular stores and Ca2+ influx, whereas a decrease in intracellular Mg2+ attenuates Ca2+ influx.

Animals↗
PubMed1996

Positive association between a DNA sequence variant in the serotonin 2A receptor gene and schizophrenia.

Sixty-two patients with schizophrenia and 96 normal controls were investigated for genetic association with restriction fragment length polymorphisms (RFLPs) in the serotonin receptor genes. A positive association between the serotonin 2A receptor gene (HTR2A) and schizophrenia was found, but not between schizophrenia and the serotonin 1A receptor gene. The positive association we report here would suggest that the DNA region with susceptibility to schizophrenia lies in the HTR2A on the long arm of chromosomes 13.

Adult↗
PubMed1996

Synergism between cisplatin and topoisomerase I inhibitors, NB-506 and SN-38, in human small cell lung cancer cells.

Topoisomerase I-targeting anticancer agents such as 7-ethyl-10-[4-(1-piperidyl)-1-piperidyl]carbonyloxy-camptothecin (CPT-11) and 6-N-formylamino-12,13-dihydro-1,11-dihydroxy-13-(beta-D- glucopyranosyl)-5H-indolo[2,3-a]pyrrolo[3,4-c]carbazole-5,7(6H)-di one (NB-506) have been developed and show strong antitumor activity against various cancers. We examined the interaction of these drugs and cisplatin (CDDP), and biochemical mechanisms of synergism between them. Interaction of drugs in human small cell lung cancer cells, SBC-3, was analyzed using the isobologram method. Combinations of CDDP with NB-506, CPT-11, and an active metabolite of CPT-11, 7-ethyl-10-hydroxy-CPT (SN-38), showed synergistic effects. Formation of DNA interstrand cross-links (ICLs) on the cells was analyzed using an alkaline elution assay and increased ICLs were observed by simultaneous exposure to CDDP (1.5 microM) and NB-506 (10 nM) compared with that in response to CDDP alone. DNA repair after ICL formation induced by 3-h exposure to CDDP (1.5 microM) was reduced by NB-506 (10 nM) exposure. On the other hand, a higher concentration of CDDP (150 microM) enhanced the topoisomerase I inhibitory activity of NB-506 and SN-38 determined by relaxation of supercoiled Escherichia coli DNA. These biological interactions might result in synergistic interactions between CDDP and NB-506 or SN-38. Topoisomerase I inhibitors and CDDP may be a key regimen for cancer chemotherapy and merit further examination.

Antineoplastic Agents↗
PubMed1996

Kinetic analysis of recurrence and survival after potentially curative resection of nonsmall cell lung cancer.

BACKGROUND: About two-thirds of the patients with nonsmall cell lung cancer (NSCLC) who undergo a potentially curative resection eventually suffer from recurrent disease. However, it has yet to be elucidated as to how survival after recurrence is influenced by different variables, including timing, type of recurrence, or other clinicopathological features. There have been few studies concentrating on the kinetics of growth of occult micrometastatic tumor cells that eventually manifest as tumor recurrence. METHODS: We retrospectively reviewed the charts of 197 patients who developed recurrence after a potentially curative resection for NSCLC. RESULTS: The median disease-free interval was a little over 1 year (395 days), as was the median postrecurrence survival-383 days. We created a model for the kinetics of recurrence by assuming that: (1) a tumor of 10(9) cells is the usual limit of detection, (2) patients generally die before the tumor reaches 10(12) cells, and (3) it takes 1 year for average lung cancer cells to show a 10-fold increase. The model indicated that as much as 10(9) tumor cells should have been present immediately after the operation. Alternatively, the residual tumor cells should have an accelerated growth after the surgery. CONCLUSIONS: These models indicate the importance of developing a sensitive detection method for occult metastatic cells and to understand the tumor dormancy mechanism.

Adult↗
PubMed1996

Size-dependent release of carboxyfluorescein from cetylmannoside-modified liposomes in human plasma.

The interaction of liposomes with human plasma was investigated using 6(5)-carboxyfluorescein (CF) as an aqueous phase marker of cetylmannoside-modified multilamellar vesicles (Man-MLVs) of various sizes. The release of CF decreased with increasing liposome concentration. The time courses of the CF release from Man-MLVs were monitored continuously and were analysed kinetically. The curves were characterized by two phases, the first-order release process and the maximum release, which represent the rate and the extent of CF release, respectively. The increase of liposome size increased the rate of release by 42% and the extent of release by 121%, respectively. These effects of liposome size on the release processes were suggested to result from the size-dependent affinities of liposomes to the human complement system. The assay system of liposomally bound fragments of complement component 3 (C3), such as C3b and/or iC3b, was developed by applying a sandwich enzyme-linked immunospecific assay. The percentage of C3 fragments to total proteins bound to liposomes increased with the size of liposomes and there was a good correlation between the extent of CF release and the percentage of C3 fragments bound. These results indicated that Man-MLVs released entrapped CF via activating the human complement system and the affinity of Man-MLV to complement increased with the size of Man-MLVs in human plasma. These in vitro results suggest the role of complement as an opsonin in the disposition of Man-MLVs in humans.

Drug Carriers↗