PubMed Health⌕ Search

Biomedical subjects

M Ichinose

Publications and source records attributed to M Ichinose.

At least 19 recordsLinked to original sources
PubMed2000

Molecular cloning of neonate/infant-specific pepsinogens from rat stomach mucosa and their expressional change during development.

To clarify the nature of rat neonate/infant-specific pepsinogens, we carried out their purification and molecular cloning. Prochymosin was found to be the major neonatal pepsinogen. The general proteolytic activity of its active form, chymosin, was, however, lower than those of pepsins A and C which are predominant in adult animals. Molecular cloning of rat prochymosin cDNA was achieved along with cDNA for another neonate-specific pepsinogen, pepsinogen F, although determination of pepsinogen F in neonatal gastric mucosa was unsuccessful, presumably due to its lack of proteolytic activity or different proteolytic specificity. Northern blot analysis confirmed that genes for prochymosin and pepsinogen F are expressed only at neonatal/infant stages and the switching of gene expression to that of pepsinogen C occurred at late infant stages. A phylogenetic tree based on nucleotide sequences showed clearly that pepsinogens fall into four major groups, namely prochymosin and pepsinogen F of the neonate/infant and pepsinogens A and C of adult animals. Although, to date, prochymosin and pepsinogen F were believed to be expressed in only a limited number of mammals, the present results suggest that they might be expressed at the neonatal/infant stage in a variety of mammals.

Aging↗
PubMed2000

Benzo[a]pyrene carcinogenicity is lost in mice lacking the aryl hydrocarbon receptor.

The contribution of the aryl hydrocarbon receptor (AhR) in induction of a battery of xenobiotic-metabolizing enzymes has been studied extensively. However, no direct proof has been obtained that it plays a role in modulating carcinogenesis. To address the question of whether AhR is required for tumor induction, we have investigated the response of AhR-deficient mice to benzo[a]pyrene (B[a]P), a widely distributed environmental carcinogen. B[a]P treatment induced expression of the cytochrome P450 gene Cyp1a1 in the skin and liver of AhR-positive mice bearing +/+ and +/- genotypes and did not induce expression of the cytochrome P450 gene Cyp1a1 in AhR-null mice in either skin or liver. In contrast, Cyp1a2 gene expression was positive in liver irrespective of the presence or absence of the AhR gene, or B[a]P treatment, although its inducibility was lost in the AhR(-/-) mouse. All AhR-positive male mice of both +/+ and +/- genotypes that received subcutaneous injection of B[a]P (2 mg) on the first and the eighth days had developed subcutaneous tumors at the site of injection at the end of the 18-week experiment. In contrast, no tumors were apparent in any of the AhR-deficient mice. Likewise, topical application of B[a]P (200 microg) at weekly intervals to the skin of female mice for 25 weeks produced skin tumors only in the AhR-positive mice. Thus the carcinogenic action of B[a]P may be determined primarily by AhR, a transcriptional regulator of the gene for CYP1A1. The results of the present study provide direct evidence that AhR is involved in carcinogenesis.

Animals↗
PubMed2000

Effect of a calcium sensitization modulator, Y-27632, on isolated human bronchus and pulmonary artery.

A recently developed pyridine derivative, Y-27632, has been reported to inhibit smooth muscle contraction by inhibiting Ca(2+)sensitization in animal experiments. However, the effect of this compound in human tissues has not yet been elucidated. The aim of the present study was to evaluate the effect of Y-27632 on human bronchi and pulmonary arteries. The tissues were obtained from lung cancer patients undergoing lung resection. Tissue responses were assessed by isometric tension measurement. Y-27632 relaxed the bronchi at basal tone with an IC(50)(concentration causing 50% relaxation of the maximal response) of 2.0+/-0.3x10(-6)M. Y-27632 also dose-dependently relaxed the bronchi precontracted by acetylcholine (ACh), histamine and neurokinin A, and the IC(50)was 3.0+/-0.4x10(-6), 2.5+/-0.5x10(-6)and 1.8 +/-0.3x10(-6)M, respectively. The dilatory effect of Y-27632 was significantly smaller in ACh-precontracted tissues compared with those of basal or histamine- and neurokinin A-induced precontracted bronchi (P<0.05). Further, Y-27632 showed an inhibitory effect on cholinergic nerve stimulation- and ACh-induced bronchial contraction to the same degree, suggesting that a modulatory effect of this compound on ACh release from nerve terminals was unlikely. Y-27632 also dilated the pulmonary arteries precontracted by phenylephrine (IC(50)= 1.6+/-0.1x10(-6)M). These data suggest that Y-27632 has a dilatory capacity on human bronchi as well as on pulmonary arteries.

Amides↗
PubMed2000

Baseline airway hyperresponsiveness and its reversible component: role of airway inflammation and airway calibre.

Airway hyperresponsiveness (AHR), in which airway inflammation has been reported to be a key factor, is an important component of asthma. However the precise role of inflammation in AHR is still unclear. In this report, airway inflammatory changes were assessed using hypertonic saline-induced sputum examination and exhaled nitric oxide analysis, and the relation between AHR to methacholine, airway calibre forced expiratory volume in one second (FEV1) and airway inflammatory indices examined. Furthermore, the changes in these variables were also examined by means of 8 weeks' open uncontrolled inhaled steroid administration (800 microg x beclomethasone x day(-1)). Asthmatic subjects had higher eosinophil counts and bradykinin concentration in induced sputum and higher exhaled NO levels, and showed AHR to methacholine. Baseline AHR significantly correlated with FEV1 but not with indices of inflammation in sputum or exhaled air. Steroid inhalation therapy was associated with a reduction in eosinophil and bradykinin concentration in sputum and NO levels in exhaled air and an improvement in FEV1 and AHR. The changes in FEV1 and AHR were significantly related to changes in markers in sputum and exhaled air (p<0.01 for each). These results suggest that baseline airway hyperresponsiveness can be predicted from the airway calibre but not from inflammatory parameters in sputum or exhaled air. In contrast, the reversible component of airway hyperresponsiveness appeared to be associated with the reduction in airway inflammation.

Administration, Inhalation↗
PubMed2000

Induction of apoptosis in glioma cells by recombinant human Fas ligand.

OBJECTIVE: Fas ligand (FasL) belongs to the tumor necrosis factor family and has the ability to induce apoptosis in susceptible target cells by binding to its receptor, Fas. It has been demonstrated recently that the FasL/Fas system plays a pivotal role in the cytocidal activity of T lymphocytes in the immune system. FasL may act as a cytotoxic effector molecule to Fas-expressing malignant tumor cells. We reported previously that Fas is commonly expressed in human brain tumor cells. In this study, we examine the possible application of FasL to therapy for malignant brain tumors. METHODS: To develop an expression system yielding large amounts of FasL, we constructed a baculovirus vector containing complementary deoxyribonucleic acid of human FasL under the control of a polyhedrin promoter. We produced human FasL in Spodoptera frugiperda (Sf9) insect cells infected by the recombinant baculovirus carrying FasL complementary deoxyribonucleic acid and studied the cytocidal activity of FasL against the T98G human glioblastoma cell line. RESULTS: FasL expression in Sf9 cells was confirmed immunocytochemically with rabbit antibody raised against the cytoplasmic domain of human FasL. The FasL released into the supernatant of cultured Sf9 cells was also verified by Western blotting, and it specifically induced apoptosis in T98G cells. The induced apoptosis by recombinant human FasL was confirmed by annexin V-fluorescein isothiocyanate staining. CONCLUSION: The present results suggest that the induction of apoptosis by the Fas/FasL system could be a new strategy for the treatment of malignant brain tumors, which are resistant to conventional therapies.

Animals↗
PubMed1999

Normal levels of serum glycoproteins maintained in beta-1, 4-galactosyltransferase I-knockout mice.

The galactose-mediated clearance of serum glycoproteins from the circulation was evaluated using beta-1,4-galactosyltransferase (beta-1,4-GalT) I-knockout mice. Partial structural study of the oligosaccharides released from mouse serum glycoproteins revealed that 77.4% of the oligosaccharides from beta-1,4-GalT I(+/+) mouse contain galactose, while 7.7% of those from beta-1,4-GalT I(-/-) mouse were galactosylated. Under the conditions, no significant change in serum protein concentrations was observed between the normal and mutant mice. The results indicate that the hepatic asialoglycoprotein receptor-mediated system is not functioning in the clearance of endogenous serum glycoproteins.

Age Factors↗
PubMed1999

Regulation of angiogenesis in human hepatomas: possible involvement of p53-inducible inhibitor of vascular endothelial cell proliferation.

Mechanisms regulating angiogenesis in human hepatomas were analyzed. Huh7 hepatoma cells transplanted into athymic mice formed highly vascularized reddish tumors with abundant microvessels, while angiogenesis by PLC/PRF/5 hepatoma cells was less remarkable. However, the production of angiogenesis stimulators such as VEGF and IL6 by Huh7 cells was much less than by PLC/PRF/5 cells. In addition, the production of angiogenesis inhibitor TSP-1 by Huh7 cells was greater than by PLC/PRF/5 cells. Therefore, the difference in angiogenesis between these two hepatomas was not explained by the production of these known angiogenesis regulators. On the other hand, PLC/PRF/5 cells but not Huh7 cells secreted an inhibitor of the proliferation of vascular endothelial cells, which was enhanced by p53-gene transfer. These results suggest that the production of this p53-inducible angiogenesis inhibitor is responsible, at least partly, for the regulation of angiogenesis in human hepatomas.

Animals↗
PubMed1999

Potentiation of GABA(A) receptor-mediated Cl-current by urotensin peptides in identified Aplysia neurons.

Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate and invertebrate central nervous systems, including those of molluscs. The effects of extracellularly applied urotensin peptides (urotensin I (UI) and urotensin II (UII)) on the GABA-induced Cl- current recorded from identified neurons (R9 and R12) of Aplysia kurodai were investigated using voltage-clamp and pressure ejection techniques. Focal application of 100 nM UI and UII potentiated the GABA-induced Cl- current without affecting the resting membrane conductance and holding current. The increase was completely reversible. The GABA-induced Cl- current also was potentiated by bath-applied UI and UII (5-10 nM). The potentiating effects of UI and UII on the GABA-induced Cl- current were concentration-dependent and completely reversible. These results suggest that neurotensin peptides may decrease neuronal excitability by potentiating the GABA(A) receptor-mediated Cl- current in the neurons of mammalian and invertebrate central nervous systems.

Animals↗
PubMed1999

A new method for the treatment of graft infection in the thoracic aorta: in situ preservation.

BACKGROUND: We have developed a new method to control graft infection by a combination of two procedures, extensive disinfection followed by tissue flap implantation, allowing preservation of the original graft. METHOD: Soon after the diagnosis of graft infection was confirmed, the wound was re-explored, and debridement, irrigation and packing with sponges soaked with 10% iodine solution were employed. This procedure was repeated every 8 hours for the first 48 hours. For the second step, tissue flaps using omentum or muscle were implanted around the graft as well as in dead space, and the wound was closed primarily. MATERIALS: A total of 6 patients were treated: 4 in the acute and 2 in the chronic phase of infection. The original procedures were a Bentall procedure + arch replacement (1), ascending aorta replacement + arch (3) and replacement of the descending aorta (2). In descending aorta cases, an extended thoracoplasty was concomitantly added to eliminate dead space in the pleural cavity. RESULTS: Graft infections were controlled in all 6 patients. One hospital death unrelated to infection was encountered. Five patients were discharged, but 1 died of a stent-graft complication. The follow-up period ranged from 4 months to 10 years. CONCLUSION: Our method of extensive disinfection followed by tissue flap coverage of the graft proved to be highly effective in controlling the serious complication of graft infection associated with surgery of the thoracic aorta.

Adult↗
PubMed1999

Bradykinin B2 antagonist HOE 140 inhibits late allergic microvascular leakage in guinea pig airways.

Because bradykinin has potent inflammatory actions, this molecule may be involved in the late allergic response (LAR). We investigated the role of the molecule in airway microvascular hyperpermeability during the LAR. Three weeks after ovalbumin (OVA) sensitization, animals were pretreated with bradykinin B2 receptor antagonist HOE 140 or vehicle for 30 min before the OVA inhalation challenge. The occurrence of LAR was judged by a two-fold increase in transpulmonary pressure (Ptp) from the baseline values. The microvascular permeability in the trachea was assessed by an index defined as the ratio of the area of vasculature labeled by the Monastral blue dye (area density percent). Significant microvascular hyperpermeability were observed during the LAR. The bradykinin concentrations in the bronchoalveolar lavage-fluid (BAL-f) were increased during the LAR. HOE 140 (0.1-10 mg/kg, s.c.) inhibited the airway microvascular hyperpermeability during the LAR dose-dependently. These findings suggest that bradykinin may play an important role in microvascular hyperpermeability during the LAR.

Animals↗
PubMed1999

Sensory nerve activation in airway microvascular permeability in guinea-pig late allergic response.

Because both bradykinin and tachykinins have a potent inflammatory action, these molecules may be involved in the late allergic response. The role of these molecules in airway microvascular permeability during the late allergic response in sensitized guinea-pigs was investigated. Three weeks after ovalbumin sensitization, the animals were pretreated with bradykinin B2 receptor antagonist HOE 140, neurokinin 1 receptor antagonist CP 96,345 or vehicle, 30 min before the ovalbumin inhalation challenge. The occurrence of the late allergic response was determined by a two-fold increase in the transpulmonary pressure from the baseline values. The microvascular permeability in the trachea was assessed by an index defined as the ratio of the area of vasculature labelled by Monastral blue dye (area density %). Significant microvascular permeability and eosinophil accumulation were observed during the late allergic response. Both the bradykinin and substance P concentrations in the bronchoalveolar lavage fluid were increased during the late allergic response. Pretreatment with HOE 140 suppressed the substance P elevation. Both HOE 140 and CP 96,345 also inhibited the airway microvascular permeability during the late allergic response without affecting the eosinophil accumulation in the airways. These findings suggest that bradykinin-mediated sensory nerve activation may play a role in microvascular permeability during the late allergic response in guinea-pigs.

Animals↗
PubMed1999

Purification and further characterization of enteropeptidase from porcine duodenum.

Enteropeptidase [EC 3.4.21.9] is a membrane-bound serine endopeptidase present in the duodenum that converts trypsinogen to trypsin. We previously cloned the cDNA of the porcine enzyme and deduced its entire amino acid sequence [M. Matsushima et al. (1994) J. Biol. Chem. 269, 19976-19982]. In the present study, we purified the porcine enzyme approximately 2,200-fold in a 12% yield from a duodenal mucosal extract to apparent homogeneity by an improved procedure comprising four steps of chromatography including benzamidine-Sepharose affinity chromatography. Lectin blotting analysis suggested that the enzyme is glycosylated mainly with N-linked carbohydrate chains of the tri- and/or tetraantennary complex type. The H and L chains of the enzyme were separated into two major bands upon SDS-PAGE under reducing conditions, suggesting that the enzyme mainly comprises two isoforms, a higher molecular weight form and a lower molecular weight form. The enzyme was also separated by lectin affinity chromatography into two major fractions, named isoforms I and II, which corresponded to the higher and lower molecular weight forms, respectively. These two isoforms appeared to be different only in the carbohydrate moiety, having essentially the same enzymatic properties. The enzyme was optimally active at pH 8.0 toward Gly-Asp-Asp-Asp-Asp-Lys-beta-naphthylamide, and was inhibited strongly by various serine proteinase inhibitors. Furthermore, it was also strongly inhibited by E-64 [L-trans-epoxysuccinyl-leucylamide-(4-guanido)-butane], a cysteine proteinase inhibitor. Substrate specificity studies involving various synthetic peptides indicated that acidic residues at the P2, P3, and/or P4 positions are especially favorable for maximal activity, but are not absolutely necessary, at least in the cases of peptide substrates.

Animals↗
PubMed1999

Role of peroxynitrite in airway microvascular hyperpermeability during late allergic phase in guinea pigs.

We investigated the role of peroxynitrite, which is formed by a rapid reaction between nitric oxide (NO) and superoxide anion (O(2)(-)), in the airway microvascular hyperpermeability during the late allergic response (LAR) in sensitized guinea pigs in vivo. The occurrence of LAR was assessed as a 100% increase in the transpulmonary pressure, which was monitored by the esophageal catheter technique. Airway microvascular permeability was assessed by Monastral blue dye trapping between the endothelium using an image analyzer. In the LAR phase (4 to 6 h after antigen inhalation), microvascular hyperpermeability and eosinophil infiltration within the airway wall were observed. NO production and xanthine oxidase (XO)/xanthine dehydrogenase activity, which are responsible for O(2)(-) production, were enhanced during the LAR. Peroxynitrite formation assessed by nitrotyrosine immunostaining was also exaggerated at that time. The microvascular hyperpermeability during the LAR was largely reduced by NO synthase inhibitor (L-NAME, 72.7% inhibition; p < 0.05), XO inhibitor (AHPP, 60.8% inhibition; p < 0. 05) and peroxynitrite scavenger (ebselen, 81.0% inhibition; p < 0. 05). L-NAME had a small but significant inhibitory effect on airway eosinophil accumulation, but AHPP and ebselen had no effect. These results suggest that excessive production of O(2)(-) and NO occurs in the LAR. These two molecules appear to cause airway microvascular hyperpermeability via peroxynitrite formation.

Animals↗
PubMed1999

Physical development of surgically treated patients with primary spontaneous pneumothorax.

STUDY OBJECTIVES: There have been many studies on the physical characteristics at the time of contraction of a primary spontaneous pneumothorax (PSP), but it has not been shown when and how such physical characteristics develop. These issues were investigated. PATIENTS AND DESIGN: Physical development of 27 male patients with PSP were examined. Their physical records were collected with the patients' permission, and standard curves, estimated from the Japanese nationwide records in the year corresponding to the ages of the patients, were plotted as control values. RESULTS: The height of patients was already greater at 6 years of age. It showed a marked increase from 11 to 14 years. The body weight was more than the standard until 9 years, but it became less after age 11, and this difference increased after age 15. Rohrer's index was significantly lower than the standard at all ages, and the difference was particularly large from 11 to 15 years. In the standard group, there was a balance between the annual height and weight gain. In the patient group, annual weight gain was similar to that in the standard group whereas height began to increase 2 years earlier, and as a result, ectomorphy, which was also observed before this age, became marked at this age. CONCLUSIONS: The rapid increase in the vertical dimension of the thorax compared with the horizontal dimension during the period of rapid physical development is considered to affect intrathoracic pressure at the apex of lung, which would have some influence on enhancing cyst formation.

Adolescent↗