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Biomedical subjects

H Yano

Publications and source records attributed to H Yano.

At least 19 recordsLinked to original sources
PubMed2003

Chromosomal imbalances associated with acquired resistance to fluoropyrimidines in human colorectal cancer cells.

The chromosomal aberrations underlying the development of resistance to fluoropyrimidines have not yet been identified. To characterise the genomic changes that induce the development of resistance to fluoropyrimidines, we used comparative genomic hybridisation (CGH) to analyse and compare the parent DLD-1 human colorectal cancer cell line and two cell lines, DLD-1/5-FU and DLD-1/FdUrd, which were resistant to 5-fluorouracil (5-FU) and 5-fluoro-2'-deoxyuridine (FdUrd), respectively. Both resistant cell lines showed a genetic aberration derived from the parental cell line DLD-1. Losses of 3p and 3q were also detected as additional genetic changes in the two resistant cell lines. Both resistant cell lines showed decreased orotate phosphoribosyltransferase (OPRT) activity, which is associated with the activity of the uridine monophosphate (UMP) synthase gene (3q13). These results suggested that the loss of 3q might be a genetic change responsible for the decreased OPRT activity and fluoropyrimidine cytotoxic response in cancer cells. Amplification of 18p11.2-p11.3 containing the thymidine synthase (TS) gene (18p11.32) was observed only in the DLD-1/FdUrd-resistant cell line, which overexpresses TS. These findings suggested that 18p amplification represents a genetic change associated with the overexpression of the TS protein. Our results indicate that chromosomal aberrations identified by CGH could explain, at least in part, acquired fluoropyrimidine resistance.

Antimetabolites, Antineoplastic↗
PubMed2003

Energy expenditure during walking with weight-bearing control (WBC) orthosis in thoracic level of paraplegic patients.

STUDY DESIGN: Comparative study of the effectiveness of walking exercise with a newly developed gait orthosis, the weight-bearing control (WBC) orthosis, for thoracic level of paraplegic patients. OBJECTIVES: To test its feasibility as a rehabilitation alternative for paraplegic patients, the energy consumption and cost during walking with WBC were calculated and compared with the values of conventional orthoses given in previous reports. SETTING: National Rehabilitation Center for the Disabled, Japan. METHODS: Four paraplegic patients with traumatic spinal cord injuries ranging from T8 to T12 participated. Experiments were conducted after 3 months of the orthotic gait training with WBC. The cardiorespiratory parameters were continuously measured at rest and during walking with a telemetric device. The steady-state value of the oxygen uptake (V(O2)), heart rate (HR), the energy consumption (J/kg/s) and energy cost (J/kg/m) were calculated. RESULTS: The average walking speed was 19.0 +/- 2.58 m/min. The steady-state value of the V(O2) and HR were 16.08 +/- 1.93 ml/kg and 147.3 +/- 10.94 b/min, respectively. The energy cost during orthotic walking tended to be better than the values of conventional orthoses, whereas the energy consumption was almost similar. CONCLUSION: WBC enables thoracic level of paraplegic patients to walk at relatively higher speed than conventional orthoses under similar energy expenditure. The special devices equipped with WBC are therefore considered to lead to improvement of the energy cost of walking. The physical intensity presumed by cardiorespiratory responses during walking with WBC is suited to promote their aerobic capacity. Therefore, it is concluded that the WBC orthosis could be an effective alternative in rehabilitation for thoracic level of paraplegic patients.

Adult↗
PubMed2003

An increase in damaged hepatocytes in rats after high intensity exercise.

AIM: The purpose of this study was to clarify the effect of various exercise intensities on damage to the hepatic parenchymal cells. METHODS: Male Wistar rats were subjected to forced exercise by treadmill running at 60 and 80% of maximum oxygen uptake (VO2max) for 120 min, sacrificed immediately and 6 h after the exercise, and then the perfused liver was stained with trypan blue solution to estimate the local damage to the liver. RESULTS: Although there were no significant increases in damaged hepatic cells immediately after both intensities of exercise, these damaged cells, in particular pericentral hepatocytes, significantly increased at 6 h after the exercise at the 80% VO2max. However, there were no significant increases in the serum glutamic-oxaloacetic transaminase (GOT) and glutamic-pyruvic transaminase (GPT) activities immediately and 6 h after both intensities of exercise. CONCLUSIONS: These results suggested that hepatocytes suffered damage after high-intensity exercise, although these histochemical findings in the liver were not observed immediately after the exercise. In addition, in the case of physical activity, there might not be an intimate relationship between the release of enzyme as a hepatic functional biomarker and hepatocyte damage.

Alanine Transaminase↗
PubMed2003

Large-scale production and properties of human plasma-derived activated Factor VII concentrate.

BACKGROUND AND OBJECTIVES: An activated Factor VII (FVIIa) concentrate, prepared from human plasma on a large scale, has to date not been available for clinical use for haemophiliacs with antibodies against FVIII and FIX. In the present study, we attempted to establish a large-scale manufacturing process to obtain plasma-derived FVIIa concentrate with high recovery and safety, and to characterize its biochemical and biological properties. MATERIALS AND METHODS: FVII was purified from human cryoprecipitate-poor plasma, by a combination of anion exchange and immunoaffinity chromatography, using Ca2+-dependent anti-FVII monoclonal antibody. To activate FVII, a FVII preparation that was nanofiltered using a Bemberg Microporous Membrane-15 nm was partially converted to FVIIa by autoactivation on an anion-exchange resin. The residual FVII in the FVII and FVIIa mixture was completely activated by further incubating the mixture in the presence of Ca2+ for 18 h at 10 degrees C, without any additional activators. For preparation of the FVIIa concentrate, after dialysis of FVIIa against 20 mm citrate, pH 6.9, containing 13 mm glycine and 240 mm NaCl, the FVIIa preparation was supplemented with 2.5% human albumin (which was first pasteurized at 60 degrees C for 10 h) and lyophilized in vials. To inactivate viruses contaminating the FVIIa concentrate, the lyophilized product was further heated at 65 degrees C for 96 h in a water bath. RESULTS: Total recovery of FVII from 15 000 l of plasma was approximately 40%, and the FVII preparation was fully converted to FVIIa with trace amounts of degraded products (FVIIabeta and FVIIagamma). The specific activity of the FVIIa was approximately 40 U/ micro g. Furthermore, virus-spiking tests demonstrated that immunoaffinity chromatography, nanofiltration and dry-heating effectively removed and inactivated the spiked viruses in the FVIIa. These results indicated that the FVIIa concentrate had both high specific activity and safety. CONCLUSIONS: We established a large-scale manufacturing process of human plasma-derived FVIIa concentrate with a high yield, making it possible to provide sufficient FVIIa concentrate for use in haemophiliacs with inhibitory antibodies.

Blood Component Transfusion↗
PubMed2003

Excision of a urachal sinus with use of a voice-controlled laparoscope.

A 34-year-old man with an umbilical urachal sinus underwent a voice-controlled robot-assisted laparoscopic excision. In the operational procedure, three trocars were inserted into the peritoneal cavity. Exploration with a laparoscope revealed a cystic lesion at the middle part of the lower abdomen that extended about 4 cm in the major axis just from the umbilicus. The caudal stump of the urachus was ligated with an absorbable clip and divided. The cephalic side of the lesion was ligated just at the umbilicus with an Endo-Loop and divided. The lesion was then peeled from the peritoneum and taken from the peritoneal cavity. The robot allowed a safer and more secure movement of the scope. The postoperative course was uneventful, the surgical wound scars were very small, and the cosmetic results were satisfactory. There was no recurrence and no transformation of the navel. Our experience was encouraging enough to suggest that voice-controlled robot-assisted laparoscopic excision in patients with urachal disease is a beneficial therapeutic option that is easy, safe, and minimally invasive, with excellent cosmetic results.

Adult↗
PubMed2003

Hand-assisted laparoscopic splenectomy for a huge splenic cyst: operative technique and case report.

We report the case of a huge splenic cyst that was successfully treated by hand-assisted laparoscopic splenectomy. A 17-year-old girl with a chief complaint of left-sided abdominal pain was admitted to our department for investigation of a splenic tumor. Ultrasonography, computed tomography, and magnetic resonance imaging revealed a huge cystic lesion in the spleen measuring approximately 10 cm in diameter. Hand-assisted laparoscopic splenectomy was safely performed to diagnose and treat the splenic tumor. The histologic diagnosis was an epithelial cyst of the spleen with no atypical cells in the cyst wall. Hand-assisted laparoscopic splenectomy may be a good method of managing a huge splenic cyst that becomes symptomatic and potentially life-threatening through enlargement, rupture, and secondary infection.

Adolescent↗
PubMed2002

[Right atrial lipoma with calcification in ascending aorta; report of a case].

A 67-year-old male was diagnosed to have a right atrial tumor by echocardiography incidentally. Computed tomography (CT) indicated a mass which showed very low radiodensity and magnetic resonance imaging (MRI) [T1-weighted] showed the high signal intensity of tumor. We could predict the mass as lipoma. Tumor removal was performed under cardio-pulmonary bypass and under ventricular fibrillation because of the calcification in ascending aorta. Microscopically the tumor was consisted of mature adipose tissue. The postoperative course was uneventful. Cardiac lipomas are rare tumors. CT and MRI are better investigations for preoperative diagnosis. After surgical excision the prognosis is excellent.

Aged↗
PubMed2001

The effects of mitiglinide (KAD-1229), a new anti-diabetic drug, on ATP-sensitive K+ channels and insulin secretion: comparison with the sulfonylureas and nateglinide.

Mitiglinide (KAD-1229), a new anti-diabetic drug, is thought to stimulate insulin secretion by closing the ATP-sensitive K+ (K(ATP)) channels in pancreatic beta-cells. However, its selectivity for the various K(ATP) channels is not known. In this study, we examined the effects of mitiglinide on various cloned K(ATP) channels (Kir6.2/SUR1, Kir6.2/SUR2A, and Kir6.2/SUR2B) reconstituted in COS-1 cells, and compared them to another meglitinide-related compound, nateglinide. Patch-clamp analysis using inside-out recording configuration showed that mitiglinide inhibits the Kir6.2/SUR1 channel currents in a dose-dependent manner (IC50 value, 100 nM) but does not significantly inhibit either Kir6.2/SUR2A or Kir6.2/SUR2B channel currents even at high doses (more than 10 microM). Nateglinide inhibits Kir6.2/SUR1 and Kir6.2/SUR2B channels at 100 nM, and inhibits Kir6.2/SUR2A channels at high concentrations (1 microM). Binding experiments on mitiglinide, nateglinide, and repaglinide to SUR1 expressed in COS-1 cells revealed that they inhibit the binding of [3H]glibenclamide to SUR1 (IC50 values: mitiglinide, 280 nM; nateglinide, 8 microM; repaglinide, 1.6 microM), suggesting that they all share a glibenclamide binding site. The insulin responses to glucose, mitiglinide, tolbutamide, and glibenclamide in MIN6 cells after chronic mitiglinide, nateglinide, or repaglinide treatment were comparable to those after chronic tolbutamide and glibenclamide treatment. These results indicate that, similar to the sulfonylureas, mitiglinide is highly specific to the Kir6.2/SUR1 complex, i.e., the pancreatic beta-cell K(ATP) channel, and suggest that mitiglinide may be a clinically useful anti-diabetic drug.

ATP-Binding Cassette Transporters↗
PubMed2001

Critical role of cAMP-GEFII--Rim2 complex in incretin-potentiated insulin secretion.

Incretins such as glucagon-like peptide-1 and gastric inhibitory polypeptide/glucose-dependent insulinotropic peptide are known to potentiate insulin secretion mainly through a cAMP/protein kinase A (PKA) signaling pathway in pancreatic beta-cells, but the mechanism is not clear. We recently found that the cAMP-binding protein cAMP-GEFII (or Epac 2), interacting with Rim2, a target of the small G protein Rab3, mediates cAMP-dependent, PKA-independent exocytosis in a reconstituted system. In the present study, we investigated the role of the cAMP-GEFII--Rim2 pathway in incretin-potentiated insulin secretion in native pancreatic beta-cells. Treatment of pancreatic islets with antisense oligodeoxynucleotides (ODNs) against cAMP-GEFII alone or with the PKA inhibitor H-89 alone inhibited incretin-potentiated insulin secretion approximately 50%, while a combination of antisense ODNs and H-89 inhibited the secretion approximately 80-90%. The effect of cAMP-GEFII on insulin secretion is mediated by Rim2 and depends on intracellular calcium as well as on cAMP. Treatment of the islets with antisense ODNs attenuated both the first and second phases of insulin secretion potentiated by the cAMP analog 8-bromo-cAMP. These results indicate that the PKA-independent mechanism involving the cAMP-GEFII--Rim2 pathway is critical in the potentiation of insulin secretion by incretins.

Animals↗
PubMed2001

A novel muscle LIM-only protein is generated from the paxillin gene locus in Drosophila.

Paxillin is a protein containing four LIM domains, and functions in integrin signaling. We report here that two transcripts are generated from the paxillin gene locus in Drosophila; one encodes a protein homolog of the vertebrate Paxillin (DPxn37), and the other a protein with only three LIM domains, partly encoded by its own specific exon (PDLP). At the myotendinous junctions of Drosophila embryos where integrins play important roles, both DPxn37 and PDLP are highly expressed with different patterns; DPxn37 is predominantly concentrated at the center of the junctions, whereas PDLP is highly enriched at neighboring sides of the junction centers, primarily expressed in the mesodermal myotubes. Northern blot analysis revealed that DPxn37 is ubiquitously expressed throughout the life cycle, whereas PDLP expression exhibits a biphasic pattern during development, largely concomitant with muscle generation and remodeling. Our results collectively reveal that a unique system exists in Drosophila for the generation of a novel type of LIM-only protein, highly expressed in the embryonic musculature, largely utilizing the Paxillin LIM domains.

3T3 Cells↗
PubMed2001

A prosurvival function for the p75 receptor death domain mediated via the caspase recruitment domain receptor-interacting protein 2.

In addition to promoting cell survival, neurotrophins also can elicit apoptosis in restricted cell types. Recent results indicate that nerve growth factor (NGF) can induce Schwann cell death via engagement of the p75 neurotrophin receptor. Here we describe a novel interaction between the p75 receptor and receptor-interacting protein 2, RIP2 (RICK/CARDIAK), that accounts for the ability of neurotrophins to choose between a survival-versus-death pathway. RIP2, an adaptor protein with a serine threonine kinase and a caspase recruitment domain (CARD), is highly expressed in dissociated Schwann cells and displays an endogenous association with p75. RIP2 binds to the death domain of p75 via its CARD domain in an NGF-dependent manner. The introduction of RIP2 into Schwann cells deficient in RIP2 conferred NGF-dependent nuclear transcription factor-kappaB (NF-kappaB) activity and decreased the cell death induced by NGF. Conversely, the expression of a dominant-negative version of RIP2 protein resulted in a loss of NGF-induced NF-kappaB induction and increased NGF-mediated cell death. These results indicate that adaptor proteins like RIP2 can provide a bifunctional switch for cell survival or cell death decisions mediated by the p75 neurotrophin receptor.

Activating Transcription Factor 2↗
PubMed2001

Attenuation by ambroxol of monochloramine-enhanced gastric carcinogenesis: a possible prevention against Helicobacter pylori-associated gastric carcinogenesis.

The effects of combined administration of a reactive oxidant, monochloramine, and a mucoregulatory agent, ambroxol, on the development of gastric cancers induced by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) were investigated in inbred Wistar rats. After receiving oral MNNG and regular chow pellets for 25 weeks, rats received regular chow pellets or chow pellets containing 20% ammonium acetate, and normal tap water or water containing 30 mM sodium hypochlorite, with or without subcutaneous injection of ambroxol at high or low doses, until the end of the experiment at week 52. Treatment with both ammonium acetate and sodium hypochlorite, which produce monochloramine, significantly increased the incidence of gastric cancers at week 52, whereas concomitant administration of ambroxol with ammonium acetate and sodium hypochlorite significantly attenuated this enhanced gastric carcinogenesis. Results also revealed that ambroxol scavenged monochloramine. Because monochloramine is closely related to Helicobacter pylori-associated gastric carcinogenesis, these findings suggest that ambroxol may prevent H. pylori-associated gastric carcinogenesis.

Ambroxol↗
PubMed2001

Different modes and qualities of tyrosine phosphorylation of Fak and Pyk2 during epithelial-mesenchymal transdifferentiation and cell migration: analysis of specific phosphorylation events using site-directed antibodies.

Integrin signaling is activated during epithelial-mesenchymal transdifferentiation (EMT) and cell migration, processes serving as models for carcinogenesis. We have shown that paxillin and p130Cas become highly tyrosine phosphorylated during these processes in NMuMG cells. Here, we examined the regulation of Fak and Pyk2, kinases implicated in this phosphorylation. Pyk2 became phosphorylated at the major autophosphorylation site (Tyr-402) and the potential Grb2-binding site (Tyr-881) during EMT. In contrast, phosphorylation of Fak at the corresponding autophosphorylation site (Tyr-397) occurred even in sedentary epithelial cells, whereas phosphorylation at Tyr-407 and Tyr-861 was induced during EMT. During cell migration, these phosphorylation events, except Fak Tyr-397, were augmented further, and phosphorylation of Fak Tyr-577 and the corresponding Pyk2 Tyr-580, both within the kinase activation loops, was also induced. In all cases, phosphorylation of the putative Grb2-binding site in Fak (Tyr-925) was almost undetectable. Although Fak and Pyk2 have several phosphorylation sites in common, Tyr-407 and Tyr-861 are unique to Fak. Our results revealed that Fak and Pyk2 are non-equivalent in the tyrosine phosphorylation events and thereby likely to evoke different downstream signaling cascades during EMT and cell migration of NMuMG cells. We also show that Fak Tyr-397 phosphorylation occurs exclusively at the cytoplasm, but not at focal contacts, in the sedentary epithelial cells. In contrast, all other tyrosine phosphorylated forms of Fak and Pyk2 are predominantly localized to focal adhesions and the cell periphery in motile cells, all colocalized with paxillin and p130Cas.

Animals↗
PubMed2001

Expression of angiogenic factors, basic fibroblast growth factor and vascular endothelial growth factor, in human biliary tract carcinoma cell lines.

In order to clarify angiogenic mechanism in biliary tract carcinoma, expressions and functions of basic fibroblast growth factor (bFGF) and its receptors (FGFR-1-4), and vascular endothelial growth factor (VEGF) and its receptors were investigated by using human biliary tract carcinoma cell lines (KMC-1, KMC-2, KMBC and KMG-C). Expression of bFGF was confirmed in KMC-1 and KMC-2, and that of FGFR-1-4 in all the cell lines except no FGFR-2 in KMC-2. Expression of VEGF was detected in all the cell lines, whereas the cell lines did not express VEGF receptors. Addition of anti-bFGF neutralizing antibody to the medium did not suppress cell proliferation, whereas exogenous bFGF with or without heparin accelerated cell proliferation in all cell lines. Addition of anti-bFGF neutralizing antibody or anti-VEGF neutralizing antibody to the co-culture of human umbilical vascular endothelial cells (HUVEC) and KMC-2 suppressed the proliferation of HUVEC. Surgically obtained cholangiocarcinoma tissues (n=7) were immunohistochemically negative to bFGF, while six of the seven were positive to VEGF. These findings suggested that human biliary tract carcinoma cells express both bFGF and VEGF not as autocrine growth factors but as angiogenic factors. On the other hand, expression of VEGF was found at a higher frequency than bFGF both in the cell lines and tissues.

Journal Article↗
PubMed2001

A strategy for the identification of proteins targeted by thioredoxin.

Thioredoxins are 12-kDa proteins functional in the regulation of cellular processes throughout the animal, plant, and microbial kingdoms. Growing evidence with seeds suggests that an h-type of thioredoxin, reduced by NADPH via NADP-thioredoxin reductase, reduces disulfide bonds of target proteins and thereby acts as a wakeup call in germination. A better understanding of the role of thioredoxin in seeds as well as other systems could be achieved if more were known about the target proteins. To this end, we have devised a strategy for the comprehensive identification of proteins targeted by thioredoxin. Tissue extracts incubated with reduced thioredoxin are treated with a fluorescent probe (monobromobimane) to label sulfhydryl groups. The newly labeled proteins are isolated by conventional two-dimensional electrophoresis: (i) nonreducing/reducing or (ii) isoelectric focusing/reducing SDS/PAGE. The isolated proteins are identified by amino acid sequencing. Each electrophoresis system offers an advantage: the first method reveals the specificity of thioredoxin in the reduction of intramolecular vs. intermolecular disulfide bonds, whereas the second method improves the separation of the labeled proteins. By application of both methods to peanut seed extracts, we isolated at least 20 thioredoxin targets and identified 5-three allergens (Ara h2, Ara h3, and Ara h6) and two proteins not known to occur in peanut (desiccation-related and seed maturation protein). These findings open the door to the identification of proteins targeted by thioredoxin in a wide range of systems, thereby enhancing our understanding of its function and extending its technological and medical applications.

Amino Acid Sequence↗
PubMed2001

Association of Trk neurotrophin receptors with components of the cytoplasmic dynein motor.

Nerve growth factor (NGF) initiates its trophic effects by long-range signaling through binding, internalization, and transport of a ligand-receptor complex from the axon terminal to the cell body. However, the mechanism by which retrograde transport of NGF takes place has not been elucidated. Here we describe an interaction between the Trk receptor tyrosine kinase and a 14 kDa light chain of cytoplasmic dynein. After transfection in human embryonic kidney 293 cells, this 14 kDa dynein light chain was found to bind to TrkA, TrkB, and TrkC receptors. Mapping experiments indicated that the 14 kDa dynein light chain binds to the distal region of the TrkA juxtamembrane domain. Coimmunoprecipitation experiments in vivo indicate that Trk receptors are in a complex with the 14 kDa light chain and 74 kDa intermediate chain of dynein. Confirming the physiological relevance of this association, a marked accumulation of Trk with the 14 kDa and the 74 kDa dynein components was observed after ligation of the sciatic nerve. The association of Trk receptors with components of cytoplasmic dynein suggests that transport of neurotrophins during vesicular trafficking may occur through a direct interaction of the Trk receptor with the dynein motor machinery.

Animals↗
PubMed2001

Preparation of prednisolone-appended alpha-, beta- and gamma-cyclodextrins: substitution at secondary hydroxyl groups and in vitro hydrolysis behavior.

The carboxyl group of prednisolone 21-hemisuccinate was conjugated to one of the hydroxyl groups of alpha-, beta-, and gamma-cyclodextrins using a coupling agent, carbonyldiimidazole. The direct coupling produced prednisolone-appended cyclodextrin conjugates in which the drug is selectively introduced at one of the secondary hydroxyl groups of cyclodextrins through an ester linkage. The aqueous solubility (> 50% w/v at 25 degrees C) of these conjugates was much higher than those of prednisolone and its 21-hemisuccinate. Prednisolone was slowly released from the conjugate: the percents of prednisolone and its hemisuccinates released from the alpha-, beta-, and gamma-cyclodextrin conjugates were 49, 57, and 85%, respectively, for 24-h. The release pathway is proposed to be via two fast acyl migrations between the 2- and 3-hydroxyl groups of cyclodextrins and between the 21- and 17-hydroxyl groups of prednisolone. The slow release of prednisolone from the ester conjugates was in sharp contrast to the fast release of the prednisolone amide conjugate reported previously. Because of relatively slow and/or site-specific release properties, the present prednisolone-appended cyclodextrin conjugates may be of value as an orally administered delayed-release and/or colon-specific prodrug.

Cyclodextrins↗