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Biomedical subjects

K Yamana

Publications and source records attributed to K Yamana.

At least 19 recordsLinked to original sources
PubMed2006

Absence of Bcl-2 and Fas/CD95/APO-1 predicts the response to immunotherapy in metastatic renal cell carcinoma.

Immunotherapy is the only available treatment for metastatic renal cell cancer (RCC), but the response rate is only about 20% and the treatment is occasionally associated with severe adverse effects. Thus, the selection of patients with a high susceptibility to immunotherapy is needed; however, there is no promising molecular marker that can predict the response to immunotherapy for RCC. This study was carried out to elucidate the potential role of apoptosis-related molecules Bcl-2 and Fas, as well as apoptotic and proliferating indexes (AI, PI) as predictors of the susceptibility of metastatic RCC to immunotherapy. Immunohistochemical examination of tumour tissues from 40 patients with metastatic RCC undergoing postoperative immunotherapy after radical nephrectomy was performed. Patients with progressive disease (PD) after immunotherapy presented with decreased survival (P=0.006). Progressive disease correlated with higher PI in the primary lesion (P=0.0087). All primary tumours of CR or PR patients were negative for Bcl-2, whereas among NC+PD patients, 40.6% were positive for Bcl-2 (P=0.0373). Patients in whom the primary tumours were both Bcl-2- and Fas-negative showed significantly better responses to immunotherapy in comparison with the remaining group (P=0.0022). The Bcl-2 and Fas status of the primary lesion may become useful criteria for the selection of patients with metastatic RCC for immunotherapy.

Adult↗
PubMed2005

Prognostic impact of FAS/CD95/APO-1 in urothelial cancers: decreased expression of Fas is associated with disease progression.

The death receptor Fas (Apo1/CD95) and Fas ligand (FasL) system is recognised as a major pathway for the induction of apoptosis in vivo, and antiapoptosis via its blockade plays a critical role in carcinogenesis and progression in several malignancies. However, the function of Fas-FasL system in urothelial cancer (UC) has not been elucidated. We therefore investigated the expression of Fas, FasL and Decoy receptor 3 for FasL (DcR3) in UC specimens and cell lines, and examined the cytotoxic effect of an anti-Fas-activating monoclonal antibody (mAb) in vitro. Immunohistochemical examinations of Fas-related molecules were performed on 123 UC and 30 normal urothelium surgical specimens. Normal urothelium showed Fas staining in the cell membrane and cytoplasm. In UC, less frequent Fas expression was significantly associated with a higher pathological grade (P < 0.0001), a more advanced stage (P = 0.023) and poorer prognosis (P = 0.010). Fas and the absence thereof were suggested to be crucial factors with which to select patients requiring more aggressive treatment. Moreover, low-dose anti-Fas-activating mAb sensitised resistant cells to adriamycin, and this synergistic effect could be applied in the development of new treatment strategy for UC patients with multidrug-resistant tumours.

Adult↗
PubMed2004

Impact of frequent Bcl-2 expression on better prognosis in renal cell carcinoma patients.

Previously, we reported that Bcl-2 was frequently expressed in renal cell carcinoma (RCC) specimens, but p53 mutation was a rare event. However, it was unclear whether Bcl-2 positivity was associated with the clinicopathological characteristics and prognosis in RCC. Therefore, we investigated the expression of Bcl-2 protein and its roles in 101 RCC specimens. In addition, the proliferation index (PI), apoptotic index (AI), caspase-3 and p53 expression were examined. The immunohistochemical method was applied for Bcl-2, caspase-3 and p53 protein expression. To investigate the proliferation activity and apoptosis of tumour cells, PI and AI were calculated based on Ki-67 and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL)-positive cells, respectively. Bcl-2 expression was detected in 72 out of 101 (71.3%) specimens. Bcl-2 positivity was inversely correlated with PI (P<0.0001) and AI (P=0.0074). Furthermore, Bcl-2 positivity was significantly correlated with better survival (P=0.0014), and was associated with lower stage (P=0.0301) and grade (P=0.0020). In RCC, frequent Bcl-2 expression was correlated with favourable character without higher PI and AI. Thus, Bcl-2 expression might be applied as a novel predictor of better prognosis in RCC patients.

Adult↗
PubMed2003

[Usefulness of semi-skeletonized right gastroepiploic artery].

The right gastroepiploic artery (RGEA) could be harvested easily and safely by using an ultrasonic scalpel. It is easier and faster not to remove a satellite vein from RGEA than to skeletonize it fully. And blood flow of the vein is important, because it is the flow of vasa vasorum of RGEA. Among 70 patients who have bypassed to right coronary arteries (RCA), 25 patients were treated with semi-skeletonized RGEA (SSK-RGEA), the other 45 patients were operated with pedicled RGEA or (if pedicled RGEA was short and small) with the other grafts. An availability of SSK-RGEA for RCA was 100%. And that of pedicled RGEA was 47% (p < 0.001). Twenty-eight patients were operated without a pump. Twenty-three of them (82%) were bypassed with RGEA. In the on-pump cases (42 patients), RGEA were used for 13 (31%) cases (p < 0.05). Early post-operative angiographies revealed 1 occlusion. But the site of occlusion was the origin of RGEA branch from a gastro-duodenal artery, and the anastomotic site was patent. This graft was supposed to be occluded post-operatively by arteriosclerosis. Flow competition occurred in two grafts. In conclusion, the SSK-RGEA was useful for RCA bypass grafting. The reliability of RGEA should increase the indication of off-pump coronary artery bypass grafting.

Cardiopulmonary Bypass↗
PubMed2002

Construction of engineered CHO strains for high-level production of recombinant proteins.

We constructed engineered CHO strains that can be used for high-level production of foreign proteins by gene-targeting. After transfecting dihydroforate reductase (DHFR)-deficient CHO cells with a plasmid carrying a loxP-green fluorescent protein (GFP) fusion gene and a DHFR gene, we screened colonies by fluorescent intensity. We selected 16 clones that expressed high levels of GFP and carried one copy of the plasmid in their chromosomes and treated them with methotrexate (MTX) to examine their ability for DHFR-mediated gene amplification. Two clones, MK1 and MK2, showed increased GFP expression upon gene amplification. In those clones, the loxP-GFP gene was integrated at a transcription-active, DHFR-mediated, gene-amplifiable locus in the chromosomes. A gene-targeting vector, carrying a loxP-fused hygromycin-resistance gene, was constructed to target desired genes in chromosomal loxP by Cre recombinase-mediated site-specific recombination. Using this cell-vector system, we could reproducibly obtain high producers of recombinant proteins by gene-targeting and gene amplification. In human monoclonal antibody production, after gene-targeting of loxP in MK2 and gene amplification with MTX, the MTX-resistant colonies showed high levels of antibody production. The most productive clone was able to produce 160 mg/l in 7 days in a low-protein medium in a spinner-flask.

Animals↗
PubMed2002

Infusion of maintenance fluids with glucose (Veen 3G) is superior to maltose infusion (Actit) in the rate of energy utilization in rabbits.

In the present study, we examined the rates of urinary excretion of glucose and maltose after an infusion of maintenance fluid with glucose or maltose in adult rabbits. Three maintenance fluids (sugar-free, 5% glucose [Veen 3G] and 5% maltose [Actit]), which contained different sugars but were identical in electrolyte and acetate compositions and concentrations (Na: 45, K: 17, Mg: 5, Cl: 37, H2PO4: 10 and CH3COO: 20 mEq/l), were used in this study. In addition, the optimum infusion speed for maintenance therapy (10 ml/kg/h) was used. Animals were not given food or water during the 10-day period of administration. The body weights of the animals were measured every day. The concentrations of total protein, albumin, free fatty acids and glucose in the serum were measured. Urine samples for determination of glucose and maltose concentrations were collected from the 1st to 10th administrations. After infusion with 5% maltose, urinary maltose excretion decreased time-dependently, while that of glucose increased. This suggests that maltase activity time-dependently increases after infusion with maltose. In addition, total sugar was only minimally excreted into urine in the 5% glucose group compared with the 5% maltose group. Thus, the glucose infusion was superior to the maltose infusion in the rate of energy utilization. However, neither the loss of body weight nor the increase in concentration of free fatty acids in serum differed significantly among the 3 groups. In conclusion, infusion of maintenance fluid with 5% maltose results in the excretion of maltose and glucose into urine, since enzymatic hydrolysis of maltose to glucose is limited to that by maltase.

Analysis of Variance↗
PubMed2001

Molecular cloning and characterization of CHM1L, a novel membrane molecule similar to chondromodulin-I.

Chondromodulin-I (ChM-I) is a cartilage-specific glycoprotein that stimulates the growth of chondrocytes and inhibits the tube formation of endothelial cells. In the present study, we identified a novel ChM-I like molecule, designated ChM1L. Cloning of full length cDNAs of human, mouse, and rat ChM1L revealed that ChM1L encodes 317 amino acids novel type II transmembrane protein. ChM1L protein was expressed on the cell surface as N-glycosylated and non-N-glycosylated protein with molecular mass of 45 and 40 kDa, respectively. In adult mouse tissues, ChM1L mRNA was highly expressed in eye, skeletal muscle, and whole rib. The temporal pattern of ChM1L mRNA was examined using whole embryo at day 10 to 19 of gestation. After day 11, ChM1L mRNA was detected and its level was progressively elevated in association with development of mouse embryo. These data suggest that ChM1L is a novel membrane molecule which is similar to ChM-I that plays a regulatory role in eye, skeletal muscle, and development of embryo.

Amino Acid Sequence↗
PubMed2000

Characterization of RNA structure by bis-pyrene-labeled 2'-O-methyloligonucleotides.

Properties of 2'-O-methyloligoribonucleotides containing two consecutive 2'-O-(1-pyrenylmethyl)uridine were investigated as a fluorescent probe to search the single strand regions of RNA. The bis-pyrene-labeled 2'-O-methyloligoribonucleotide (OMUpy2) induced the formation of pyrene dimer upon hybridization with the complementary oligoribonucleotides and showed remarkable appearance of broad structureless fluorescence at 480 nm. Contrarily, when OMUpy2 was hybridized with the complementary oligodeoxyribonucleotides, such enhancement of fluorescence was scarcely observed. When various OMUpy2 were applied to E. coli 5S-rRNA, the fluorescence intensity at 480 nm was varied in a sequence specific manner.

Base Sequence↗
PubMed2000

Synthesis of oligonucleotide derivatives containing a bis-pyrene residue in the main chain.

The oligonucleotide having the bis-pyrene residue in the main chain was synthesized. The preparation of the bis-pyrene was started from the conversion of 2,2-bis-(bromomethyl)-1,3-propanediol into the protected bis-amino derivative. The reaction of the bis-amino derivative with 1-pyrenebutyric acid using DCC/HOBT afforded the desired bis-pyrene. This compound was then converted to the protected phosphormidite. The oligonucleotides possessing the bis-pyrene were synthesized by using the amidite. The oligonucleotides having the bis-pyrene residue can bind to DNA sequence in an aqueous solution to give the duplex with comparable thermal stability as that of the unmodified DNA/DNA duplex. The significantly enhanced pyrene-excimer fluorescence was observed upon hybridization of the bis-pyrene modified oligonucleotides with DNA.

Base Sequence↗
PubMed2000

Effects of intravenous theophylline, aminophylline and ethylenediamine on antigen-induced bronchoconstriction in guinea pigs.

The antiasthmatic effect of i.v. injection of theophylline was compared with that of aminophylline by using an antigen-induced bronchoconstriction model in sensitized guinea pigs. Both theophylline and aminophylline showed dose-dependent inhibition of antigen-induced bronchoconstriction. Statistically significant differences were observed at theophylline doses of 20 and 40 mg/kg and at aminophylline doses of 25 and 50 mg/kg. Thus, antiasthmatic effects of both drugs appeared to be similar. In addition, intravenous ethylenediamine did not influence either airflow in normal guinea pigs or bronchoconstriction induced by antigen at doses up to 30 mg/kg. In conclusion, the ethylenediamine in aminophylline may not influence the antiasthmatic action of theophylline, and the therapeutic effects of theophylline and aminophylline are suggested to be similar.

Aminophylline↗
PubMed1999

2'-Pyrene modified oligonucleotide provides a highly sensitive fluorescent probe of RNA.

Oligonucleotide 9mers containing 2'-O-(1-pyrenylmethyl)uridine [U(pyr)] at the center position were synthesized by using a protected U(pyr) phosphoramidite. The UV melting behaviors indicate that the pyrene-modified oligonucleotides can bind to both their complementary DNA and RNA in aqueous solution. When compared with the unmodified oligonucleotides, the pyrene-modified oligonucleotides showed higher affinity for DNA while exhibiting lower affinity for RNA. The pyrene-modified oligonucleotides in diluted solution exhibited fluorescence typical of pyrene monomer emission [lambdamax 378 (band I) and 391 nm (band III)]. When these oligomers bound to DNA, the fluorescence intensity ratio of band III/band I was increased. With this fluorescence change, a new broad emission (lambdamax 450 nm) due to exciplex between the pyrene and an adjacent nucleobase appeared. In contrast, addition of RNA to the pyrene oligonucleotides resulted in enhancement of the pyrene monomer emission with decrease in the fluorescence band ratio. The extent of the emission enhancement was found to be highly dependent on the nucleobase adjacent to the U(pyr) in the pyrene oligomers. The pyrene oligonucleotide containing dC at the 3'-site of the modification showed remarkable increase (approximately 250 times) in fluorescence (375 nm) upon binding to complementary RNA. The present findings would open the way to the design of a highly sensitive fluorescent probe of RNA.

Circular Dichroism↗
PubMed1999

Synthesis of oligonucleotides containing a new azobenzene fragment with efficient photoisomerizability.

The azobenzene derivatives possessing substituents of ROCH2CH2O- and-CH2CH2OR' or -CONHCH2CH2OR' at p,p'-positions, where R and R' are 4,4'-dimethoxytrityl and 2-cyanoethyl-N,N'-diisopropylphophoramidite, have been synthesized for linking two oligonucelotide segments. It has been found that the azobenzene linkers efficiently undergo trans-cis isomerization by exposing to UV light. The conversion efficiency showed slight dependence on structure or conformation of oligonucleotides attached to the azobenzene chromophore. The cis-form of the azobenzene in oligonucleotides was sufficiently stable at low temperature under dark. The present findings would open the way for light switch of nucleic acid structures.

Azo Compounds↗
PubMed1999

Synthesis and properties of oligonucleotides containing 2'-pyrenylalkyluridine.

The synthesis, binding and fluorescence properties of oligonucleotides containing the uridine modified at the 2'-position by a pyrene group using different length of linker arm have been described. It is demonstrated that the oligonucleotides possessing a C3-amide group at the 2'-position display an enhanced signal of the pyrene monomer fluorescence upon binding to DNA segments.

Base Sequence↗
PubMed1999

Study on RNA structure by pyrene-labeled 2'-O-methyloligoribonucleotides.

Properties of 2'-O-methyloligoribonucleotides containing 2'-O-(1-pyrenylmethyl)uridine were investigated as the fluorescent probe to search the single strand regions on RNA secondary and tertiary structure. The pyrene-labeled 2'-O-methyloligoribonucleotide (OMUpy) showed remarkable increase of fluorescence intensity to 333-fold at 375 nm when hybridized with the complementary oligoribonucleotide. When OMUpy, complementary to loop or stem regions, was applied to E. coli 5S-rRNA, the fluorescence intensities were increased in a sequence specific manner. The difference of the fluorescence intensities corresponds to the higher-order structure of 5S-rRNA, suggesting that pyrene-labled 2'-O-methyloligoribonucleotide can be applicable to search single strand regions of RNA.

Base Sequence↗
PubMed1998

Genetic polymorphisms and mutations of the lipoprotein lipase gene in Japanese schoolchildren with hypoalphalipoproteinemia.

Lipoprotein lipase (LPL) is an important enzyme for the hydrolysis of TG on lipoproteins, and its activity is positively correlated with the plasma levels of high density lipoprotein cholesterol (HDL-C). To investigate the association between the LPL gene and low HDL-C levels, we studied two polymorphisms (Hind III and Pvu II) and three mutations (Asn291Ser, Gly188Glu and LPL(Arita)) of the LPL gene in 114 children with low HDL-C levels (<40 mg/dl) and 194 control children using polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) techniques (PCR-RFLP). The frequency of the Pvu II +/+ genotype was significantly higher in the children with low-HDL/high-TG (TG>100 mg/dl, 90th percentile level among Japanese schoolchildren) than in the other children (vs the low-HDL/normal-TG children, chi2 = 7.49, p < 0.01; vs control children, chi2 = 7.23, p < 0.01). Pvu II+ allele of the LPL gene was associated with elevated TG levels in low HDL-C groups. In addition, we found one heterozygote of LPL(Arita) (deletion of G at base 916 in exon 5, the most common mutation of LPL deficiency in Japanese), among the low-HDL/high-TG subjects. The other two variants were not detected in either the low-HDL children or control children. LPL Asn291Ser and Gly188Glu have been presumed to be rare in the Japanese population. In conclusion, our results suggest that hypoalphalipoproteinemia with elevated TG level may be associated with genetic variations of the LPL gene.

Adolescent↗
PubMed1997

Coronary artery revascularization concomitant with vascular surgery.

Patients with vascular disease and coronary disease are usually treated initially by coronary artery bypass grafting (CABG), and vascular surgery is generally performed later. In this study we assessed the feasibility of combined CABG and vascular surgery in a single operation. Between 1988 and 1995, 16 patients received combined operations for vascular and cardiac lesions and the clinical results were assessed. There were no operative or hospital deaths. The mean time for operation was 421 min and the duration of the stay in the intensive care unit (ICU) was a mean of 3.6 days. In one patient with an ischemic left leg, the left internal thoracic artery (ITA) had become a collateral source of the ischemic leg, and the need for preoperative angiography of the ITA in such patients was indicated. The combined operation clearly takes longer than either vascular surgery or CABG alone, but the length of the postoperative intensive care unit stay was essentially the same as that after a single operation and the patient was still managed safely after the combined operation. In patient requiring both operations, the combined procedure therefore appears to be safe and to have a good clinical outcome.

Aged↗