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Biomedical subjects

M Ohara

Publications and source records attributed to M Ohara.

At least 73 records · Page 4Linked to original sources
PubMed1997

Upregulation of aquaporin-2 water channel expression in chronic heart failure rat.

Aquaporin-2 (AQP2) mediates vasopressin-regulated collecting duct water permeability. Chronic heart failure (CHF) is characterized by abnormal renal water retention. We hypothetized that upregulation of aquaporin-2 water channel could account for the water retention in CHF. Male rats underwent either a left coronary artery ligation, a model of CHF, or were sham operated. 31-33 d after surgery, mean arterial pressure (MAP) and cardiac output were measured in conscious animals, and the animals were killed 24 h later. Cardiac output (CO) and plasma osmolality were significantly decreased and plasma vasopressin increased in the CHF as compared to the sham-operated rats. Both mRNA and protein AQP2 were significantly increased in the kidneys of the CHF rats. The effect of oral administration of a nonpeptide V2 vasopressin receptor antagonist, OPC 31260, was therefore investigated. OPC 31260 induced a significant increase in diuresis, decrease in urinary osmolality, and rise in plasma osmolality in the OPC 31260-treated CHF rats as compared to untreated CHF rats. The mRNA and protein AQP2 were significantly diminished in both cortex and inner medulla of the treated CHF rats. In conclusion, an early upregulation of AQP2 is present in CHF rats and this upregulation is inhibited by the administration of a V2 receptor antagonist. The results indicate a major role for vasopressin in the upregulation of AQP2 water channels and water retention in experimental CHF in the rat.

Animals↗
PubMed1997

Neutrophil elastase inhibitor, ONO-5046, modulates acid-induced lung and systemic injury in rabbits.

BACKGROUND: Acid instillation leads to direct lung and to secondary systemic organ injury, probably via activated macrophages and neutrophils. This study investigated the effects of neutrophil elastase on organ injury after unilateral lung acid instillation by administrating a specific neutrophil elastase inhibitor, ONO-5046, before acid instillation. METHODS: Three groups of anesthetized rabbits (n = 12 in each group) underwent tracheostomies, and instillations were made into their right lower lobe airspaces with either phosphate buffered saline (pH, 7.4; volume, 1.2 ml/kg; n = 12) or HCl (pH, 1.25; volume, 1.2 ml/kg; n = 24). In half of the acid-instilled rabbits, ONO-5046, 10 mg/kg, was given intravenously 15 min before the HCl instillation, and then 10 mg x kg(-1) x h(-1) of the drug was continuously infused throughout the experiment. The other groups of animals received the vehicle intravenously. Anesthesia and mechanical ventilation was continued for 8 h, whereas arterial blood gases were sampled intermittently. Eight hours after saline or acid instillation, the animals were killed, and their lungs, heart, kidneys, liver, and small intestines were harvested. Wet-to-dry weight ratios (W/ D) and myeloperoxidase (MPO) assays of these organs were done, and elastase assays on the bronchoalveolar lavage fluids (BALF) obtained from each lung also were performed. RESULTS: Pretreatment with ONO-5046 attenuated the physiologic changes seen in the vehicle-treated animals. Significant decreases in W/D of the noninstilled lungs and of the small intestine and normalization of the oxygenation of the experimental animals occurred. The ONO-5046 pretreatment did not affect the neutrophil sequestration in the lungs or in the other organs as determined by neutrophil counts in BALF and by the MPO assays. CONCLUSIONS: A neutrophil elastase inhibitor, ONO-5046, administered immediately before acid instillation attenuated the physiologic changes seen in the vehicle-treated animals. The drug blocked neutrophil elastase but did not block neutrophil sequestration in the lungs, although the drug improved measurements of lung injury.

Animals↗
PubMed1997

Complement partially mediates acid aspiration-induced remote organ injury in the rat.

BACKGROUND: Acid aspiration into one lung is known to cause both a local as well as remote organ injury characterized by neutrophil sequestration and subsequent edema. This study investigated investigated the role of the complement cascade in the development of acid aspiration-induced local lung and remote organ injuries using K-76 COONa (K76), an anticomplement agent that inhibits the complement pathway at the C5 step, and its usefulness as a treatment drug. METHODS: Anesthetized rats underwent tracheostomy and insertion of a cannula. K76 was intraperitoneally administrated prior to or immediately after the instillation of 0.1 ml of HCl (0.1N) or phosphate buffer solution (PBS) into the left lung. Inflammatory responses were evaluated by tumor necrosis factor alpha (TNF alpha) in the plasma and the bronchoalveolar lavage fluid (BALF) (n = 4), tissue myeloperoxidase (MPO), wet-to-dry weight ratio (W/D ratio) (n = 6), and protein concentration in the BALF (n = 6). RESULTS: Acid instillation caused an increase in the plasma TNF alpha, which was significantly attenuated by the administration of K76 prior to or after the acid instillation. Acid instillation to the left lung resulted in an increase of MPO and W/D ratios of the left lung, the right lung, and the small intestine. The administration of K76 inhibited the increase of MPO in these organs. K76 inhibited the increase of W/D ratios of the right non-instillated lung and the small intestine. Acid instillation led to increased protein concentration in the BALF of the left lung, which was not inhibited by K76. K76 administrated after the acid instillation had the same effects. TNF alpha in the BALF was not detected in all groups. CONCLUSION: These results suggest that localized acid aspiration induces, through the C5a step of the complement system-dependent mechanisms, TNF alpha formation and neutrophil sequestration, which caused the increase of endothelial permeability of the systemic organs. K76 is effective as a treatment drug in modulating some of the injuries caused by the acid instillation, but further investigations is warranted as to its potential as a therapeutic agent.

Animals↗
PubMed1997

Granulocytapheresis in the treatment of patients with rheumatoid arthritis.

The G-1 column is an extracorporeal type granulocytapheresis device packed with 220 g cellulose acetate beads to which granulocytes and monocytes specifically adhere. A total of 59 rheumatoid arthritis patients with elevated granulocyte counts from 4 hospitals in Japan received 2 apheresis sessions of 1 h duration/week for a total of 8 times over a period of 4 weeks. About 55% of the leukocytes which entered the G-1 column were adsorbed onto the beads: 95% were granulocytes, 3.5% monocytes, and 0.4% lymphocytes. Clinical and efficacy assessments showed improvements in swollen joints (p < 0.01), tender joints (p < 0.001), the active joint score (p < 0.001), duration of morning stiffness (p < 0.01), and grip strength (p < 0.001). In good responders, the improvements were observed for up to 12 weeks following the last apheresis. Exacerbation was noted in 2 patients. It is suggested that the efficacy of the G-1 column is attributable to the removal or suppression of hyperactive leukocytes and inflammatory cytokines, inducing a kind of immunomodulation.

Adsorption↗
PubMed1997

epr, which encodes glycylglycine endopeptidase resistance, is homologous to femAB and affects serine content of peptidoglycan cross bridges in Staphylococcus capitis and Staphylococcus aureus.

Staphylococcus capitis EPK1 produces a glycylglycine endopeptidase, ALE-1 (M. Sugai, T. Fujiwara, T. Akiyama, M. Ohara, H. Komatsuzawa, S. Inoue, and H. Suginaka, J. Bacteriol. 179:1193-1202, 1997), which hydrolyzes interpeptide pentaglycine chains of cell wall peptidoglycan of S. aureus. Characterizations of the enzyme activity and cloning of ale-1 revealed that ALE-1 is very similar to prolysostaphin produced by S. simulans bv. staphylolyticus. Strain EPK1 is resistant to lysis by ALE-1 and by lysostaphin. A gene that renders the cells resistant to glycylglycine endopeptidase (epr) was found 322 bp upstream of and in the opposite orientation to ale-1. The deduced amino acid sequence of epr showed similarities to FemA and FemB, which have been characterized as factors essential for methicillin resistance of S. aureus. Inactivation of either femA or femB causes decreased resistance to methicillin, increased resistance to lysostaphin, and decreased glycine content in the interpeptide chains of peptidoglycan. Therefore, femAB is suggested to be involved in the addition of glycine to pentapeptide peptidoglycan precursor. S. aureus with epr on a multicopy plasmid had phenotypes similar to those of femAB mutants except that it did not alter resistance level to methicillin. These results suggest that epr and femAB belong to the protein family involved in adding amino acids to the pentapeptide peptidoglycan precursor and that epr is involved in the addition of serine to the pentapeptide.

Acetylglucosaminidase↗
PubMed1997

Purification and molecular characterization of glycylglycine endopeptidase produced by Staphylococcus capitis EPK1.

A novel staphylolytic enzyme, ALE-1, acting on Staphylococcus aureus, was purified from a Staphylococcus capitis EPK1 culture supernatant. The optimal pH range for staphylolytic activity was 7 to 9. ALE-1 contains one Zn2+ atom per molecule. Analysis of peptidoglycan fragments released by ALE-1 indicated that the enzyme is a glycylglycine endopeptidase. The effects of various modulators were determined, and we found that o-phenanthroline, iodoacetic acid, diethylpyrocarbonate, and Cu2+ reduced the staphylolytic activity of ALE-1. beta-Casein, elastin, and pentaglycine were poor substrates for ALE-1. Molecular cloning data revealed that ALE-1 is composed of 362 amino acid residues and is synthesized as a precursor protein which is cleaved after Ala at position 35, thus producing a mature ALE-1 of 35.6 kDa. The primary structure of mature ALE-1 is very similar to the proenzyme form of lysostaphin. It has the modular design of an N-terminal domain of tandem repeats of a 13-amino-acid sequence fused to the active site containing C-terminal domain. Unlike lysostaphin, ALE-1 does not undergo processing of the N-terminal repeat domain in broth culture. ale-1 is encoded on the plasmid. Protein homology search suggested that ALE-1 and lysostaphin are members of the novel Zn2+ protease family with a homologous 38-amino-acid-long motif, Tyr-X-His-X(11)-Val-X(12/20)-Gly-X(5-6)-His.

Amino Acid Sequence↗
PubMed1997

Infrequent alterations of the p16 (MTS-1) gene in human gastric cancer.

p16 (MTS-1, multiple tumor suppressor gene 1), a putative tumor suppressor gene, is one of the cyclin-dependent kinase inhibitors (CDI) and it regulates the G1/S transition of the cell cycle. To clarify the role of p16 in primary gastric cancer, we have investigated somatic mutations of this gene by using the polymerase chain reaction/single strand conformation polymorphism (PCR-SSCP) method. In 23 surgical specimens of primary gastric cancer, none were detected in exon1 and exon 2. Among the 6 human gastric cancer cell lines examined, PCR products were not found in 2, MKN28 and MKN45, suggesting the presence of homozygous deletions. No mutation was found in the other 4 cell lines. Furthermore, decreased expression levels were not observed in 13 gastric cancer tissues by reverse transcription PCR (RT-PCR). Considering the above results of PCR-SSCP and RT-PCR, genetic alterations of the p16 gene are rarely implicated in human gastric cancer tumorigenesis.

Actins↗
PubMed1997

[A study of the effects of antidepressants on the GABAA receptor and its complex based on the drug actions on the power-spectral changes of rat hippocampal EEG induced by GABA antagonists and inverse agonists].

To analyze the effects of antidepressants on the GABAA receptor, we investigated how the chronic administration of antidepressants (10 mg/kg twice a day for three or seven days, ip) influenced the power-spectral changes induced by pentylenetetrazol (PTZ; a GABA antagonist; 27.5 mg/kg) or beta-carboline-3-carboxylic-acid-methylester (beta-CCM; an inverse agonist; 1 mg/kg) on rat hippocampal EEGs. PTZ and beta-CCM are known to inhibit the chloride ionophore and benzodiazepine receptor (GABAA receptor complex), respectively. After the ip injection of both compounds, the EEG power under 12 Hz increased to about five times that before injection. Between the rats that did not receive any antidepressants and all those injected with the drugs for 3 days or treated with desipramine (DMI) for 7 days, there were no apparent changes in the effect of PTZ or beta-CCM. However, in the rats treated with imipramine, fluoxetine or trazodone for 7 days, the increase in power after the injection of PTZ or beta-CCM was apparently suppressed. In these rats, the power values were less than three times those before the dosing of PTZ or beta-CCM. DMI is known to inhibit the re-uptake of norepinephrine (NE), while the other three antidepressants inhibit that of serotonin (5-HT). Trazodone is also reported to block the 5-HT2 sites. These observations might indicate that the chronic administration of antidepressants prompted the function of the GABAA receptor complex. Moreover, it is also suggested that, to that action, the effect of antidepressants on the 5-HT system or interaction between the 5-HT system and GABA receptors might play some role.

Animals↗
PubMed1997

[A case of liver metastases from leiomyosarcoma in the chest wall which was made resectable by chemoembolization].

We here report a recently experienced case in which TAE and intra-arterial infusion chemotherapy for treatment of liver metastases of leiomyosarcoma in the chest wall caused a shrinking of the metastasized focus, thus facilitating liver resection. Patient; a 38-year-old man Present History and Courses; Resection of leiomyosarcoma in his chest wall was done in May, 1994. However, a local recurrence was noted in September, 1995, and the tumor was removed. Then, he received systemic chemotherapy with CDDP (100 mg) and ADM (45 mg). Abdominal CT and ultrasonic examinations made in February, 1996 revealed liver metastases at S2,5,8. Angiography detected densely stained images of tumors at a number of sites along with S2,5,8. Since these were thought unresectable, TAE therapy with EPIR (30 mg) and lipiodol (4 ml) was attempted 3 times. Then, a reservoir for intra-hepatic arterial infusion was implanted in April, 1996 and EPIR at a dose of 30 mg (150 mg in total) was given through arterial infusion, resulting in tumor disappearance at S5,8 but further growth of the tumor metastasizes at S2. Therefore, a resection of the left lateral segment of liver was done August 23. Though he was discharged in October, metastasis was found in the thoracic spine in December. Thus, he underwent resection of the vertebral arch including the tumor.

Adult↗
PubMed1997

[A case of unresectable advanced cancer of the gall bladder successfully treated by arterial infusion therapy with cisplatin].

A 70-year-old male was admitted for obstructive jaundice. He was diagnosed as an unresectable advanced cancer of the gall bladder that was stage IV associated with direct extension of the liver (Hinf3) and the bile duct (Binf3), and with enlargement of paraaortic lymph node (N4(+)) by image analyses. Intraarterial infusion therapy with cisplatin (CDDP, 50 mg) was started through the common hepatic artery. Since the primary tumor and the enlarged paraaortic lymph node shrank markedly and the bile duct was completely obstructed, additional arterial infusion with CDDP (50 mg) was made. CT examination thereafter revealed that the paraaortic lymph node enlargement disappeared although thickening of the gall bladder wall still remained. Therefore this case was considered as a complete response (CR). Then, a reservoir for hepatic arterial infusion was implanted and CDDP (a total of 230 mg) was repeatedly infused 5 times. CT scanning images taken 7 months after the start of the treatment showed neither primary tumor nor enlargement of paraaortic lymph node. An extensive cholecystectomy was performed. Histopathological examination revealed signet-ring cell carcinoma located in all layers of the gall bladder. Factors indicating clinicopathological stage were se, hinf1, vs0, bw1, hw0 and ew2 (according to the General Rules for Surgical and Pathological Studies on Cancer of Bile duct).

Aged↗
PubMed1997

Cancer cell cycle and adoptive immunotherapy using lymphokine-activated killer cells.

The mechanism underlying the lymphokine-activated killer (LAK) cell cytotoxicity to tumor cells in LAK therapy was studied using flow cytometric cell cycle analysis of Daudi cells. It was suggested that the degree of LAK cell cytotoxicity varied depending upon the phase of the cell cycle that the Daudi cells were in: the resting (G0)-phase/preparation for DNA synthesis (G1)-phase, the DNA synthesis (S)-phase or the preparation for mitosis (G2)-phase/mitosis (M)-phase. The levels of expression of intercellular adhesion molecule-1 (ICAM-1), lymphocyte function-associated antigen-3 (LFA-3) and fibronectin (FN), surface antigens playing important roles in LAK cell cytotoxicity, in the different phases of the Daudi cell cycle have been investigated. The level of the expression of ICAM-1 and LFA-3 was significantly higher in S-phase cells and G2/M-phase cells relative to that in G0/G1 phase cells. The level of expression of FN, however, was significantly lower in S-phase cells and G2/M-phase cells in relation to that in G0/G1 phase cells. On the basis of these results, it may be inferred that the degree of LAK cell cytotoxicity is closely related to the cell cycle phase that the Daudi cells are in and the level of expression of surface antigens associated with the cell cycle phase. For Daudi cells treated with cis-diamminedichloroplatinum (II) (CDDP) and mitomycin-c (MMC), the enhancement of the degree of LAK cell cytotoxicity was directly related to the decrease in the proportion of cells in the S-phase. It may be suggested, therefore, that the proportion of cells in the S-phase in a tumor serves as an index of the sensitivity of the tumor cells to LAK cell cytotoxicity, and that designing a therapeutic strategy on the basis of the analysis of tumor cell cycle would help to improve the success of LAK therapy.

Antineoplastic Agents↗
PubMed1997

Enhancement of eosinophil survival by lipopolysaccharide through releasing granulocyte-macrophage colony stimulating factor from mononuclear cells from patients with bronchial asthma.

BACKGROUND: The mechanism of bronchoobstruction in asthmatics following inhalation of lipopolysaccharide (LPS) is unclear. OBJECTIVE: In this study we have investigated the effects of the LPS on eosinophil survival rate in stimulating peripheral blood mononuclear cells (PBMCs) from patients with asthma. METHODS: PBMC supernatants from 10 asthmatic patients and 4 healthy subjects were compared for eosinophil survival rate using the same purified eosinophils. Two x 10(6) cells/ml of PBMCs were cultured for 24 hours in RPMI 1640 containing 10% fetal bovine serum along with 10 micrograms/ml of LPS. 10(6) cells/ml of eosinophils were incubated for 96 hours in the presence of PBMC-derived culture supernatants at 75% in volume. RESULTS: The viability of eosinophils incubated with PBMC supernatants from asthmatic patients stimulated with LPS was higher, 62.5% +/- 10.6% (mean +/- SD), than that without LPS, 26.9% +/- 10.8%, and also higher than that of PBMCs from healthy subjects with LPS, 40.0% +/- 15.4%. This increasing activity of asthmatic PBMC stimulated with LPS was markedly inhibited from 72.2% +/- 9.7% to 38.5% +/- 6.8% by addition of mouse anti-human GM-CSF antibody to the PBMC supernatant but not mouse anti-human IL-5 antibody. CONCLUSION: These results suggest that LPS enhances eosinophil survival in asthmatics by increasing the production of GM-CSF from PBMCs.

Adult↗
PubMed1996

Preferential activation of CD4+V beta 5.2/5.3+ intestinal intraepithelial lymphocytes in the inflamed lesions of Crohn's disease.

To analyze the nature of intestinal intraepithelial lymphocytes (iIELs) in inflammatory intestinal disease, we established T cell lines of iIELs isolated from endoscopic biopsied ileal and colonic mucosa of Crohn's disease patients. Seven T cell lines from the inflamed terminal ileum of 13 patients, but none of 16 T cell lines from normal terminal ileum, have shown a deviation of T cell receptor variable region gene usage and were enriched in the proportion of CD4+V beta 5.2/5.3+ cells. CD4+V beta 5.2/5.3+ cells in the T cell lines were not increased after stimulation with purified protein derivatives or 65-kDa heat-shock protein but significantly increased after stimulation with staphylococcal enterotoxins C1 and D. Those cells showed increased cytolytic activity against target cells cross-linked by anti-V beta 5.2/5.3 and produced a large amount of interferon-gamma. These results indicated that CD4+V beta 5.2/5.3+ iIELs were preferentially activated in the inflamed lesions of Crohn's disease and may play a possible role in the triggering and progression of human inflammatory intestinal disease.

Adolescent↗
PubMed1996

End results of simultaneous splenectomy in patients undergoing total gastrectomy for gastric carcinoma.

BACKGROUND: Splenectomy often is performed simultaneously with total gastrectomy for gastric carcinoma to facilitate dissection of splenic hilar lymph nodes. Splenectomy, however, should be avoided as frequently as possible because of its important role in the reticuloendothelial system and because of its sometimes severe complications. We evaluated the end results of simultaneous splenectomy with total gastrectomy. METHODS: The effect of splenectomy on survival was examined by retrospective analysis of 245 patients undergoing total gastrectomy for gastric carcinoma. Of these, 154 underwent splenectomy, and 91 did not. Prognostic factors for patients undergoing total gastrectomy were determined. The relationship to postoperative complications also was analyzed. RESULTS: No significant differences overall were found between the 5-year survival of the patients undergoing total gastrectomy with or without splenectomy. No correlation to any prognostic factor was seen with splenectomy. In contrast, splenectomy was independently associated with postoperative complications. CONCLUSIONS: In this retrospective study simultaneous splenectomy at total gastrectomy for gastric cancer did not have an effect on the survival rate of patients undergoing total gastrectomy, and it sometimes caused severe complications.

Female↗
PubMed1996

Soluble complement receptor type 1 inhibited the systemic organ injury caused by acid instillation into a lung.

BACKGROUND: Acid aspiration into one lung causes contralateral lung injury and systemic organ injury; this injury is thought to be mediated by the sequestration of activated neutrophils. Recombinant human soluble complement receptor 1 (sCR1) inhibits both the classical and alternative complement pathways; this study investigated the role of the complement system in unilateral acid lung injury by measuring the effects of administering sCR1 before or immediately after acid instillation. METHODS: Anesthetized rats (n = 18 in each group) underwent tracheostomy and insertion of a cannula into the anterior segment of the left lung. Then either 0.1 ml 0.1 N hydrochloric acid (HCl group) or 0.1 ml pH 7.4 phosphate buffered-saline (PBS group) was instilled. Fifteen minutes before (pre-sCR1 group) or 15 min after (post-sCR1 group) the acid was instilled, 10 mg/kg sCR1 was administered intravenously. Four hours after the acid instillation, rats were killed. In an additional 4 rats in each group, blood and bronchoalveolar lavage fluids obtained 1 h after the instillation of either acid or PBS were analyzed for tumor necrosis factor-alpha activity. RESULTS: The instillation of acid led to an increased wet-to-dry ratio of 5.2 +/- 0.1 in the acid-instilled lungs compared with their contralateral lungs (4.7 +/- 0.06). These values were greater than the values of 4.6 +/- 0.2 and 4.5 +/- 0.03 in the PBS-instilled lungs and their contralateral lungs, respectively (P < 0.05). The administration of sCR1 before or immediately after the instillation of acid did not attenuate the increase in the wet-to-dry ratio of the acid-instilled lungs. However, the small but consistent increase in the wet-to-dry ratio of the contralateral lungs was attenuated by the sCR1 infusions (P < 0.05). The instillation of acid increased the protein concentration in the bronchoalveolar lavage fluids from the injured lungs (1,000 +/- 206 micrograms/ml) compared with the protein concentration measured in the bronchoalveolar lavage fluids from their contralateral lungs (254 +/- 55 micrograms/ml). The administration of sCR1 before or immediately after the instillation of acid did not decrease the protein concentration in the bronchoalveolar lavage fluids from the acid-instilled lungs. The myeloperoxidase activity was increased in the acid-instilled lung, in their contralateral lung, and in the small intestines of the animals. The infusions of sCR1 before or immediately after the administration of acid led to significant decreases in the myeloperoxidase activities measured in the lungs and the intestines of the treated animals. Plasma tumor necrosis factor-alpha activity was only increased (2.7 +/- 1.1 U/ml) in the animals that had received acid instillations. The infusions of sCR1, administered either before or immediately after the acid instillations, significantly decreased the measured tumor necrosis factor-alpha activity in the plasma (0.5 +/- 0.6 and 1.0 +/- 0.7 U/ml, respectively). CONCLUSIONS: The results suggest that the complement system plays an important role in the pathogenesis of the injury of the contralateral lung and of the small intestine after unilateral instillation of acid to the lung. Further investigation is warranted to determine the clinical utility of antiinflammatory agents in acid-induced lung injury.

Acids↗