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Biomedical subjects

M Numata

Publications and source records attributed to M Numata.

At least 37 records · Page 2Linked to original sources
PubMed1998

Identification of a mitochondrial Na+/H+ exchanger.

The electroneutral exchange of protons for Na+ and K+ across the mitochondrial inner membrane contributes to organellar volume and Ca2+ homeostasis. The molecular nature of these transporters remains unknown. In this report, we characterize a novel gene (YDR456w; renamed NHA2) in Saccharomyces cerevisiae whose deduced protein sequence is homologous to members of the mammalian Na+/H+ exchanger gene family. Fluorescence microscopy showed that a Nha2-green fluorescent protein chimera colocalizes with 4',6-diamidino-2-phenylindole staining of mitochondrial DNA. To assess the function of Nha2, we deleted the NHA2 gene by homologous disruption and found that benzamil-inhibitable, acid-activated 22Na+ uptake into mitochondria was abolished in the mutant strain. It also showed retarded growth on nonfermentable carbon sources and severely reduced survival during the stationary phase of the cell cycle compared with the parental strain, consistent with a defect in aerobic metabolism. Sequence comparisons revealed that Nha2 has highest identity to a putative Na+/H+ exchanger homologue (KIAA0267; renamed NHE6) in humans. Northern blot analysis demonstrated that NHE6 is ubiquitously expressed but is most abundant in mitochondrion-rich tissues such as brain, skeletal muscle, and heart. Fluorescence microscopy showed that a NHE6-green fluorescent protein chimera also accumulates in mitochondria of transfected HeLa cells. These data indicate that NHA2 and NHE6 encode homologous Na+/H+ exchangers and suggest they may be important for mitochondrial function in lower and higher eukaryotes, respectively.

Amino Acid Sequence↗
PubMed1998

Inhibition of inducible nitric oxide synthase prevents LPS-induced acute lung injury in dogs.

Nitric oxide (NO) is produced by inducible NO synthase (iNOS) after LPS stimulation, and reacts with superoxide to form peroxynitrite. We hypothesize that in LPS-induced lung injury, NO generated by iNOS plays a key role through the formation of peroxynitrite. We developed an acute lung injury dog model by injecting LPS, and examined the effects of selective iNOS inhibitors, aminoguanidine (AG) and S-methylisothiourea sulfate (SMT), on the LPS-induced lung injury. At 24 h after LPS injection, arterial oxygen tension and mean arterial pressure decreased, and shunt ratio and lung wet-to-dry weight ratio increased. On histology, the LPS group had marked neutrophil infiltration and widening of the alveolar septa. On immunohistochemistry, iNOS and nitrotyrosine, a major product of nitration of protein by peroxynitrite, were observed in the interstitium, capillary wall, and neutrophils in the airspaces of the LPS group. Treatments with AG and SMT prevented worsening of gas exchange, hemodynamics, and wet-to-dry weight ratio. On histology, AG and SMT treatments markedly suppressed lung injury, iNOS protein, and nitrotyrosine production. We conclude that NO released by iNOS may play a critical role in the pathogenesis of LPS-induced acute lung injury. This study suggests that iNOS inhibitors may have potential in the treatment of LPS-induced acute respiratory distress syndrome.

Animals↗
PubMed1998

New stacking variant of Laves phase found in (Ti0.95 V0.05) Co2 alloy.

Microstructures of the Laves phase alloy, (Ti0.95 V0.05) Co2, were studied by high resolution electron microscopy and electron diffraction. In this alloy system, coexistence of several kinds of layered structures was observed. Among these structures, a new stacking variant was found and was analyzed to be ABCAB'A'C'BCA'C'B'. This structure belongs to the trigonal system of the space group P3m1 (no. 164). The lattice parameters presented in the hexagonal system are a = 0.4727 +/- 0.0009 nm and c = 4.628 +/- 0.008 nm. This structure is called 12T in the Ramsdell notation and 4323 in the Zhdanov symbol, and is classified into hP3m1-(6i)5(3f)(3e)(2d)12(2c)6 using the Wyckoff notation.

Alloys↗
PubMed1998

Bafilomycin A1 induces apoptosis in the human pancreatic cancer cell line Capan-1.

Bafilomycin A1, a specific inhibitor of vacuolar type H(+)-ATPase, can inhibit the growth of a variety of cultured cells in a dose-dependent manner, but its mechanism is unclear. The aim of this study was to examine whether bafilomycin A1 inhibits the growth of Capan-1 human pancreatic cancer cells through apoptosis. The effect of bafilomycin A1 on tumour growth in vitro and in vivo was examined using an MTT assay and an in vivo tumour model. The presence or absence of apoptosis was determined by morphology and DNA analysis of tumour cells. The concentration of bafilomycin A1 for 50 per cent inhibition of cell viability during 72 h by the MTT assay was 5 nm. In DNA analysis, a ladder of fragmented DNA was detected in Capan-1 cells treated with bafilomycin A1 at concentrations greater than 10 nm for 24 h. Nude mice bearing a xenografted Capan-1 cell line tumour received 4 weeks of bafilomycin A1 (1.0 mg/kg per day). This treatment significantly inhibited tumour growth compared with controls after 21 days (P < 0.05). Histopathological examination of tumour cells in the treated group demonstrated signs of apoptosis with chromatin condensation and cell shrinkage. These observations suggest that bafilomycin A1 inhibits the growth of Capan-1 human pancreatic cancer cells through apoptosis.

Adenocarcinoma↗
PubMed1998

Serum level of eosinophil cationic protein in patients with chronic cough: relationship to blood eosinophils and airway hyperresponsiveness.

We measured the serum level of eosinophil cationic protein (ECP), determined the blood eosinophil count, and assessed pulmonary function by spirometry and airway responsiveness to methacholine in 80 patients with a cough lasting longer than 3 weeks without an obvious cause. The serum level of ECP was above the cutoff value of 15.7 ng/mL (mean + 2 SD in 105 healthy control adults) in 30 (37.5%) of 80 patients (high-serum-ECP group). The blood eosinophil count was significantly higher in the high-serum-ECP group than in the normal-serum-ECP group (p < 0.01). The cumulative dose of methacholine causing a 35% decrease in respiratory conductance (PD35Grs) was significantly lower in the high-serum-ECP group than in the normal-serum-ECP group (p < 0.001). The serum concentration of ECP was correlated with the blood eosinophil count and the PD35Grs (r = 0.59, p < 0.001 and r = -0.48, p < 0.001, respectively). These findings suggest a possible role for serum level of ECP in management of patients with chronic cough.

Adult↗
PubMed1998

A poison information service via an automated facsimile (fax) system: an adjunct to the operator-based service.

BACKGROUND: Poison centers are faced with the escalating costs of specialist staffing and increased investments in hardware and databases despite deficit funding. We developed an automated fax information system to access poison information from any fax machine without special training or equipment. METHODS: We provided a 3-month trial service of the fax system in conjunction with the regular operator-based service and analyzed the fax access log, followed by a questionnaire to the 2204 affiliate members regarding the use of the fax. RESULTS: A total 657 accesses to the fax system were made, of which 105 (16%) were unsuccessful; 342 (52%) were made to retrieve the user's manual, 85 (13%) to retrieve the index pages, and 230 (35%) to retrieve documentation on specific substances. The most frequently accessed items concerned disc battery ingestion (13.5%), salicylates (10.3%), mamushi viper (7.1%), acetaminophen (5.8%), and sodium hypochlorite (3.8%). The questionnaires were returned by 666 (30.2%) members; 93 (14%) had actually used the fax system with the average frequency of 1.8 times/user, 63% (59/93) of the respondents considered the service satisfactory, and 33% (31/93) said it was somewhat unsatisfactory. CONCLUSIONS: The automated fax information system was accepted and handled by users with only minor difficulty. A facsimile information service may have a valuable role in providing poisoning information and has potential benefits in cases of environmental disasters.

Consumer Behavior↗
PubMed1998

Cationic trypsinogen produced by human pancreatic ductal cancer has the characteristics of spontaneous activation and gelatinolytic activity in the presence of proton.

We examined whether human pancreatic ductal cancer cells express and secrete pancreatic cationic trypsinogen in vitro which can be spontaneously converted into active trypsin at acidic pH (pH 4.5-5. 5), in contrast to anionic trypsinogen. Cationic trypsinogen expression at the mRNA level was observed in differentiated Capan-1 and BxPC-3 cell lines. However, expression was not detected in either poorly-differentiated Panc-1 or undifferentiated MIAPaCa-2 cell line. The gelatinolytic activity of the activated form of trypsinogen in each conditioned medium in the presence of enterokinase (1.0 microg/ml) (a band with a molecular weight of approximately 23 kDa) corresponded well to the level of cationic trypsinogen mRNA. The spontaneous activation of trypsinogen also was observed by gelatin zymography of the acid-loaded conditioned medium (pH 5.5). These findings suggest that trypsinogen produced by human pancreatic ductal cancer has the characteristics of spontaneous activation and gelatinolytic activity in the presence of proton.

Culture Media, Conditioned↗
PubMed1998

[Renal damage in a chronic active hepatitis C patient receiving interferon-alpha therapy].

A 68-year-old male patient with chronic active hepatitis C was treated with interferon-alpha (IFN-alpha) for a period of 5 months. The patient responded well to the IFN therapy showing substantial improvement in liver function and disappearance of HCV-RNA. However, one year after the treatment he was found to have developed proteinuria and showed a reduction in Ccr. Renal biopsy findings were as follows: Light microscopy showed diffuse expansion of mesangial cells with a focal/local increase in cellularity accompanied by capillary loop thickening. Splitting of the basement membrane was also present. An immunofluorescent study showed that IgA was localized predominantly in the peripheral capillary wall. Electron microscopy showed that there was mesangial cell interposition between the peripheral capillary wall and endothelial cells. Furthermore, endothelial cells were expanded and numerous platelets were seen in the capillary lumen. These findings were compatible with focal MPGN accompanied by activation of endothelial cells. These histological data suggest two clinical disease entities: late-onset renal damage induced by IFN-alpha alone, and HCV-induced renal damage possibly modified by the direct effect of IFN-alpha on the endothelium. The present case suggests that IFN therapy for HCV may produce a particular type of renal damage, under the influence of either IFN or HCV infection, and/or both.

Aged↗
PubMed1997

Regulation and immunohistochemical analysis of stress protein heme oxygenase-1 in rat kidney with myoglobinuric acute renal failure.

Intramuscular injection of hypertonic glycerol solution to rats results in acute renal injury. In this model, the proximal tubules are characteristically damaged. After glycerol injection renal glutathione (GSH) levels drastically decreased. On the other hand, stress protein heme oxygenase-1 (HO-1) was induced. When N-acetyl cysteine was administered to rats before 1 h glycerol injection, renal function was obviously improved. In this condition, the renal GSH content were sustained in the normal levels and HO-1 protein levels were decreased compared with those of glycerol-treated rats. Induction of HO-1 was accompanied by reduced renal GSH content. In addition, to investigate whether the location of HO-1 protein induced by glycerol injection is restricted to injured region or not in the kidney, we determined the localization of HO-1 protein using immunohistochemical staining. HO-1 protein was identified in the epithelia of the distal tubules, Henle's loop and collecting ducts, but not in the injured proximal tubules.

Acetylcysteine↗
PubMed1997

Identification and characterization of BRDT: A testis-specific gene related to the bromodomain genes RING3 and Drosophila fsh.

The RING3 gene encodes a 90-kDa mitogen-activated nuclear protein. In proliferating cells, including in leukemia, RING3 has serine-threonine kinase and autophosphorylation activities. The cloning of D26362, a gene closely related to RING3, suggests a gene family. RING3 and D26362 are also related to the Drosophila developmental gene fsh. A database search for further members of the RING3 family identified an EST derived from a testis-specific library. cDNA clones representing the full coding sequence of the gene were isolated. The gene encodes a protein of 947 amino acids with extensive homology to RING3, D26362, and fsh. Similar to these proteins, it possesses two bromodomain motifs and a PEST sequence. Northern analysis of 16 normal tissues and eight cancer cell lines shows transcripts of 3.5 and 4.0 kb expressed specifically in testis. The gene has been named BRDT (for bromodomain, testis specific). PCR analysis of a panel of monochromosomal human/rodent hybrid cell lines and the GeneBridge 4 panel of radiation hybrids localizes the gene to chromosome 1p between markers WI-7719 and WI-3099 (D1S2154).

Amino Acid Sequence↗
PubMed1997

Neurotrophin-3 expression in human pancreatic cancers.

Some neurotrophic factors stimulate process outgrowth in peripheral and/or central nerve fibres. There is no published report that has focused on the expression of neurotrophic factors in human pancreatic cancer except basic fibroblast growth factor. This study was therefore designed to examine the mRNA and protein levels of neurotrophin-3 (NT-3), which is one of the representative neurotrophic factors. The mRNA level for NT-3 was first investigated in eight pancreatic cancers and two samples of normal pancreas, using reverse transcription-polymerase chain reaction (RT-PCR). NT-3 protein expression was then studied in 47 human pancreatic cancers, using a monoclonal antibody against human NT-3 protein. There was a notable difference in the level of NT-3 mRNA between normal and pancreatic carcinoma tissues, with no evident difference in the expression of the beta-actin gene. Immunohistochemically, 34 of 47 pancreatic cancers (72 per cent) were mildly to markedly immunoreactive for NT-3 in the cytoplasma. Immunoreactivity was usually more pronounced at the infiltrative margins of the tumours. These observations suggest that pancreatic carcinoma overexpresses NT-3.

Adult↗
PubMed1997

Region-specific meiotic recombination in Schizosaccharomyces pombe: the rec11 gene.

Mutations in the rec11 gene of Schizosaccharomyces pombe reduce meiotic recombinant frequencies by as much as a factor of 300 on chromosome III but less than a factor of 4 in the intervals tested on chromosomes I and II. To gain insight into the function of this region- (or chromosome-) specific activator of recombination, we have cloned and sequenced the rec11 gene. Meiotic crosses with rec11 disruption mutations placed the rec11 gene 6 cM from ade6 on chromosome III. Transcripts of rec11 accumulated transiently at 2-3 h after induction of melosis in a pat1-114 (Ts) mutant. Reverse transcriptase/polymerase chain reaction (RT-PCR) analysis of these transcripts revealed eight introns. The spliced RNA is predicted to encode a polypeptide of 923 amino acids with only very limited homology to reported proteins. The transient accumulation of rec11 transcripts and the phenotype of rec11 mutations suggest that the novel rec11 gene product acts early in meiosis to activate recombination preferentially on chromosome III.

Base Sequence↗
PubMed1996

Immunolocalization and pharmacological relevance of oligopeptide transporter PepT1 in intestinal absorption of beta-lactam antibiotics.

A polyclonal antibody (anti-PepT1/C) was raised against the rabbit intestinal H(+)-coupled oligopeptide transporter, PepT1. Anti-PepT1/C detected 70-80-kDa protein in crude membranes obtained from rabbit duodenum, jejunum and ileum. PepT1 was localized in the brush-border of the absorptive epithelial cells by subcellular fractionation of membranes on a sucrose density gradient and by immunohistochemistry using light and electron microscopy. Transport activity for cephalosporins and dipeptide expressed in Xenopus laevis oocytes injected with total mRNA obtained from rabbit small intestine was eliminated completely by prehybridization of the mRNA with antisense oligonucleotide against the 5'-coding region of rabbit PepT1 cDNA.

Amino Acid Sequence↗
PubMed1996

Total synthesis of glycononaosyl ceramide with a sialyl dimeric Le(x)-sequence.

The first total synthesis of glycononaosyl ceramide with a sialyl dimeric Le(x) sequence 1 is described. Regio- and stereo-selective glycosylations of sialyl donors 6,7,8 with the suitably protected Le(x) trisaccharide acceptors 9,10 beta were performed to give the expected tetrasaccharides 15 and 21, which were converted into the corresponding donors 20 and 22. Boron trifluoride etherate-promoted glycosylation of 20 with pentasaccharide acceptor 11 afforded regioselectively the expected nonasaccharide 23. After replacing benzyl groups of 23 by acetyl groups, the anomeric acetate was transformed into the alpha-trichloroacetimidate 27. The crucial coupling between 27 and (2S, 3R, 4E-3-O-benzoyl-2-N-tetracosanoylsphingenine 3 was executed to afford completely protected beta-glycoside 28. Finally, selective cleavage of the methyl ester and N,O-deprotection of 28 gave the target ganglioside 1.

Carbohydrate Sequence↗
PubMed1996

O-acetylated xyloglucan in extracellular polysaccharides from cell-suspension cultures of Mentha.

Extracellular polysaccharide produced by suspension-cultured Mentha cells consisted of 50% neutral sugars, 32% uronic acid and 10% of protein. The ammonium oxalate-soluble fraction of this polysaccharide contained 30% hemicellulose and 70% pectic substances. The purified hemicellulose contained xylose, glucose, arabinose, galactose, mannose and fucose residues in a molar ratio of 41.6:31.3:13.1:11.1:1.3:1.6. It was identified as a xyloglucan from its neutral sugar composition and by methylation analysis and cellulase treatment: the principal neutral sugar was arabinose. The presence of O-acetyl residues was confirmed with 1H NMR, 13C NMR and GC-mass spectrometry. The total acetyl content in the polysaccharide was 4%. The point of attachment of the O-acetyl residue was shown to be at position 6 of the galactosyl residue.

Acetylation↗