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Biomedical subjects

T Kodama

Publications and source records attributed to T Kodama.

At least 397 records · Page 22Linked to original sources
PubMed1996

Condensation of silicone oil on the posterior surface of a silicone intraocular lens during vitrectomy.

PURPOSE: We experienced a complication caused by the condensation of silicone oil on the surface of a silicone intraocular lens during pars plana vitrectomy. METHODS: A 74-year-old woman with proliferative vitreoretinopathy underwent a pars plana vitrectomy in her left eye, which contained silicone oil and a silicone intraocular lens. RESULTS: Intraoperatively, condensation of silicone oil on the posterior surface of a silicone intraocular lens caused a loss of visibility during fluid/gas exchange. The silicone oil droplets could not be removed. CONCLUSION: Surgeons should avoid direct contact of silicone oil with silicone intraocular lens.

Aged↗
PubMed1996

Acetylcholine releases of mesopontine PGO-on cells in the lateral geniculate nucleus in sleep-waking cycle and serotonergic regulation.

1. Five adult cats were prepared with standard sleep-recording electrodes, microinjection cannulae in the bilateral mesopontine tegmentum X area and cannulae for microdialysis probes in the LGN. 2. Dialysates were collected at 5 min intervals during SWS, REM sleep and wakefulness, and during pre- and post-stimulation periods of 5MeODMT microinjection in the bilateral mesopontine tegmentum of freely moving cats. 3. A REM sleep-specific increase of ACh release was observed in the LGN, but not out of the LGN. 4. ACh release was depressed up to 33% by bilateral 5MeODMT microinjection in the mesopontine tegmentum where the microinjection of carbachol also depressed ACh in the LGN probably by stimulating the auto receptor. 5. Our observations indicate that PGO-on neurons of mesopontine tegmentum release more ACh in the LGN during REM sleep by burst discharge than during wakefulness and SWS, and that presumptive cholinergic PGO-on cells are regulated by serotonergic inputs.

Acetylcholine↗
PubMed1996

Effects of gamma-linolenic acid and its positional isomer pinolenic acid on immune parameters of brown-Norway rats.

Male Brown-Norway rats given purified diets containing safflower oil (SFO, linoleic acid, 18:2 n-6), evening primrose oil (EPO, gamma-linolenic acid, 6,9,12- 18:3 n-6) or Korean pine seed oil (PSO, 5,9,12- 18:3) at the 10% level were immunized twice with intraperitoneal ovalbumin, on days 14 and 35 of the feeding diets, and killed one day after the second booster. The relative population of CD4+ T-lymphocytes in the spleen was significantly lower in rats fed SFO than in those fed EPO or PSO, while that of CD8+ subsets remained unchanged. There was a significant increase in the splenic production of IgG and IgE in the PSO group compared to the SFO group, while EPO significantly increased IgE. The periodical response patterns of the serum levels of IgG and IgE varied depending on the source of dietary fats, and the initial rise of total immunoglobulins tended to be higher in the EPO group. The release by peritoneal exudate cells of histamine was comparable among three groups irrespective of saturation by calcium ionophore A23187, while PSO significantly increased leukotriene B4 production. These observations not only indicate specific roles of gamma-linolenic acid but also diverse influences of different octadecatrienoic acids in various immune measurements.

Animals↗
PubMed1996

Two mechanisms for platelet-mediated killing of tumour cells: one cyclo-oxygenase dependent and the other nitric oxide dependent.

We have tried to identify the cytotoxic effectors in platelet-mediated tumour cell killing, using two tumour cell lines K562 (a chronic myelogenic leukaemic cell line) and LU99A (a lung cancer cell line), which are both sensitive to platelet cytotoxicity. Cyclo-oxygenase inhibitors, acetylsalicylic acid (ASA) and indomethacin, effectively inhibited the platelet-mediated killing of K562 cells, but not that of LU99A cells. In contrast, inhibitors of the nitric oxide (NO) pathway. NG-nitro-1-arginine (L-NA), haemoglobin and methylene blue, reduced the cytotoxic activity of platelets against LU99A, but not against K562. Synthetic analogues of platelet cyclo-oxygenase products thromboxane A2/ prostaglandin H2(TXA2/PGH2) exerted cytotoxicity against K562 cells but not against LU99A cells. Electron microscopic study showed that TXA2/PGH2 analogues induced bleb formation and disruption of the plasma membrane of K562 cells. K562 cells enhanced the production of TXA2 by platelets, as inferred from the accumulation of thromboxane B2 (TXB2), a spontaneous hydrolysis product of TXA2. LU99A cells had no such effects. These results indicate that platelets kill these two tumour cell lines through different mechanisms. In K562, the cyclooxygenase products TXA2/PGH2 possibly play a significant role but in LU99A the NO pathway seems to be involved.

Aspirin↗
PubMed1996

Helicobacter pylori cagA gene and expression of cytokine messenger RNA in gastric mucosa.

BACKGROUND & AIMS: Helicobacter pylori strains possessing the cagA gene are thought to be associated with gastroduodenal diseases. Furthermore, some cytokines are considered to play a role in gastric mucosal inflammation. The aim of this study was to investigate the relationship between cagA gene and cytokine messenger RNA (mRNA) expression in gastric mucosa. METHODS: In 160 patients, the cagA gene was detected using polymerase chain reaction, and interleukin (IL) 1 beta, IL-6, IL-7, IL-8, IL-10, and tumor necrosis factor (TNF) alpha mRNA were detected using reverse-transcription polymerase chain reaction. RESULTS: Specimens infected with cagA gene-positive strains (cagA-positive specimens) had significantly more severe infiltration of polymorphonuclear leukocytes and mononuclear cells than those infected with cagA gene-negative strains (cagA-negative specimens). Levels of expression of IL-6, IL-7, IL-8, IL-10, and TNF-alpha mRNA were significantly higher in H. pylori-positive than H. pylori-negative patients. Furthermore, the level of IL-8 mRNA expression was significantly higher in cagA-positive than cagA-negative specimens. CONCLUSIONS: cagA-positive strains induce the expression of IL-8 mRNA, suggesting that IL-8 may play important roles in the pathogenesis of gastroduodenal diseases associated with H. pylori infection.

Adult↗
PubMed1996

Dietary protein modifies oxidized cholesterol-induced alterations of linoleic acid and cholesterol metabolism in rats.

Effects of dietary protein on oxidized cholesterol-induced alterations in linoleic acid and cholesterol metabolism were studied in 4-wk-old male Sprague-Dawley rats, using casein and soybean protein as dietary protein sources. The rats were fed one of the two proteins in cholesterol-free, 0.3% cholesterol or 0.3% oxidized cholesterol mixture diets using a pair-feeding protocol for 3 wk. In the soybean protein-fed group, rats fed oxidized cholesterol did not have lower activity of liver microsomal delta6 desaturase, the rate-limiting enzyme in the metabolism of linoleic acid to arachidonic acid, compared with rats fed cholesterol-free diet, whereas in the casein-fed group the desaturase activity was significantly greater in rats fed oxidized cholesterol than in those fed cholesterol-free diet. This was in contrast to a significant reduction in liver microsomal delta6 desaturase activity by cholesterol, irrespective of protein source. In general, these changes were reflected in the desaturation indices of liver phospholipids. Furthermore, soybean protein significantly increased the fecal excretion of neutral and acidic steroids and tended to reduce (P = 0.082) the accumulation of oxidized cholesterols in the liver. Thus, soybean protein partly modified some of the undesirable effects of oxidized cholesterol through its hypocholesterolemic effect and possibly through the modulation of hepatic delta6 desaturase activity.

Animals↗
PubMed1996

Endobronchial lipoma: a report of three cases.

Although lipomas are common benign neoplasms of soft tissue, endobronchial lipoma is rare. We have treated three patients with endobronchial lipoma over the five years. In two of them lesions were located in segmental or subsegmental bronchi and produced no symptoms. There are very few such cases reported in the English medical literature. In the first case, pneumonectomy was performed because of destruction of the lung due to recurrent pneumonia. The second case had no symptoms and the tumor was located at the bifurcation of right B4a and B4b. A right middle lobectomy was performed, because the distal end of the tumor could not be visualized by fiberoptic bronchoscopy. In the third case, which was a case of lung cancer, an endobronchial lipoma was found during fiberoptic bronchoscopy, and was completely removed endoscopically. Due to their benign nature, endobronchial lipomas should be initially treated with endoscopic surgery or endoscopic laser vaporization. Nevertheless, if the tumor is large and dumbbell-shaped on tomography or CT, endoscopic procedures are not appropriate. Furthermore, if destructive pulmonary change due to the tumor is severe, the remaining peripheral lung will not recover after endoscopic procedures, even if they are removed successfully. When the biopsy specimen is too small to allow evaluation of the whole tumor, surgical resection should also be considered for definitive diagnosis.

Aged↗
PubMed1996

A randomized cross-over trial of granisetron and dexamethasone versus granisetron alone: the role of dexamethasone on day 1 in the control of cisplatin-induced delayed emesis.

We studied the role of dexamethasone (DEX) administered on day 1 in controlling cisplatin-induced delayed emesis. Forty patients were randomly allocated to receive either granisetron (GRN) and DEX on day 1, or the same dose of GRN alone. On days 2-5, all the patients received metoclopramide and DEX. They were crossed over to the other antiemetic regimen with their second course of chemotherapy. Thirty-one patients were evaluable for efficacy. The mean visual analogue scale scores for nausea on days 1 and 2 were 9.1 and 18.8 mm for GRN and DEX, and 16.3 and 28.5 mm for GRN alone, respectively (P<0.05 on day 2). The mean numbers of emetic episodes on days 1-3 were 0.036, 0.46 and 0.36 for GRN and DEX, and 0.39, 0.89 and 0.57 for GRN alone, respectively (P<0.01 on day 1). Hiccups and restlessness were noted in 38% and 33% of cycles, respectively. Addition of DEX to GRN on day 1 thus enhanced the control of delayed emesis.

Adult↗
PubMed1996

Synthetic collagen-like domain derived from the macrophage scavenger receptor binds acetylated low-density lipoprotein in vitro.

The bovine macrophage scavenger receptor is a 70 kDa membrane protein that is trimerized on the macrophage cell surface. The receptor binds modified low-density lipoproteins (LDL). The core binding site is located within 22 residues at the C-terminus of the collagen-like domain of the receptor. The Lys residue at position 337 plays an important role in ligand binding. Here, the collagen-like domain was constructed using a peptide architecture technique, in which three collagenous peptide chains were crosslinked at their N-termini. The crosslinked peptide showed a collagen-like structure by circular dichroism and existed mainly in a monomeric triple helical form as shown by gel exclusion chromatography. The triple-stranded peptide was demonstrated to bind acetylated LDL (Ac-LDL) using regions derived from Gly323 to Lys340 of the natural bovine scavenger receptor. However, a single-stranded peptide with the same amino acid sequence did not bind Ac-LDL. Furthermore, a triple-stranded mutated peptide in which Lys corresponding to Lys337 in the mother protein was substituted with Ala showed no binding activity to Ac-LDL. These results, taken together, indicate that the synthetic collagen-like peptide has a similar structure to the binding site in the scavenger receptor, and support the view that the collagen-like domain of the natural scavenger receptor recognizes Ac-LDL.

Amino Acid Sequence↗
PubMed1996

Collagenous macrophage scavenger receptors.

Collagen, the most abundant protein in the human body, is a major constituent of extracellular matrix. Among macrophage membrane proteins, type I and II scavenger receptors and MARCO contain a collagenous domain. Analysis of type I and II receptor knockout mice and histochemical studies indicate that these proteins play roles in scavenger, adhesion and host defense functions of macrophages.

Animals↗
PubMed1996

Species specificity in the blood cholesterol-lowering effect of YM-16638.

1. The compound YM-16638, [[5-[[3-(4-acetyl-3-hydroxy-2-propylphenoxy)propyl] thio]-1,3,4-thiadiazol-2-yl]thio] acetic acid was developed in a series of in vitro and in vivo studies as a leukotriene D4 receptor antagonist. 2. In a clinical trial as a leukotriene antagonist drug, this compound was found to have a potent serum cholesterol lowering effect in normolipidaemic healthy male volunteers. 3. In the present study, we investigated the serum cholesterol lower effect of this compound in various species of experimental animals. 4. Administration of YM-16638 did not cause a significant decrease in serum total cholesterol (TC) in mice (up to 200 mg kg-1, body weight per day for 28 days), rats (200 mg kg-1 for 15 days) or rabbits (90 mg kg-1 for 18 days). In hamsters, administration of YM-16638 orally or by peritoneal injection at 50 mg kg-1 or more daily for 7 days caused a significant decrease in serum TC and the rate of body weight gain. In monkeys, serum TC did not change in YM-16638-administered squirrel monkeys (50 mg kg-1 daily for 3 weeks), but a significant decrease in serum TC was observed in cynomolgus monkeys (33% decrease at 30 mg kg-1 for 4 weeks) and rhesus monkeys (27% decrease at 30 mg kg-1 for 3 weeks) without any serious decrease in body weight. These results were consistent with those in a phase I study with human subjects. In contrast, serum alanine aminotransferase (ALT) level decreased in all animals after YM-16638 treatment. 5. From these results, we conclude that YM-16638 has a potent hypocholesterolaemic effect, but that this effect if species-specific and is only recognized clearly in human subjects and old-world monkeys.

Alanine Transaminase↗
PubMed1996

Purification and characterization of 2-oxoglutarate:ferredoxin oxidoreductase from a thermophilic, obligately chemolithoautotrophic bacterium, Hydrogenobacter thermophilus TK-6.

2-Oxoglutarate:ferredoxin oxidoreductase from a thermophilic, obligately autotrophic, hydrogen-oxidizing bacterium, Hydrogenobacter thermophilus TK-6, was purified to homogeneity by precipitation with ammonium sulfate and by fractionation by DEAE-Sepharose CL-6B, polyacrylate-quaternary amine, hydroxyapatite, and Superdex-200 chromatography. The purified enzyme had a molecular mass of about 105 kDa and comprised two subunits (70 kDa and 35 kDa). The activity of the 2-oxoglutarate:ferredoxin oxidoreductase was detected by the use of 2-oxoglutarate, coenzyme A, and one of several electron acceptors in substrate amounts (ferredoxin isolated from H. thermophilus, flavin adenine dinucleotide, flavin mononucleotide, or methyl viologen). NAD, NADP, and ferredoxins from Chlorella spp. and Clostridium pasteurianum were ineffective. The enzyme was extremely thermostable; the temperature optimum for 2-oxoglutarate oxidation was above 80 degrees C, and the time for a 50% loss of activity at 70 degrees C under anaerobic conditions was 22 h. The optimum pH for a 2-oxoglutarate oxidation reaction was 7.6 to 7.8. The apparent Km values for 2-oxoglutarate and coenzyme A at 70 degrees C were 1.42 mM and 80 microM, respectively.

Amino Acid Sequence↗
PubMed1996

Elevated progastrin-releasing peptide(31-98) concentrations in pleural effusions due to small-cell lung carcinoma.

Progastrin-releasing peptide (ProGRP) is a specific and actively secreted product from small-cell lung carcinoma (SCLC) cells. Recently, an enzyme-linked immunosorbent assay, which uses monoclonal and polyclonal antibodies to recombinant proGRP(31-98), a common region of ProGRP, was established. We measured concentrations of ProGRP (31-98), neuron-specific enolase (NSE) and carcinoembryonic antigen (CEA) in carcinomatous and infectious pleural effusions. Significantly increased ProGRP(31-98) and NSE values were found in carcinomatous pleurisy due to SCLC compared to the other carcinomatous pleurisy and infectious pleurisy. CEA values were significantly increased in carcinomatous pleural effusions compared with those in infectious effusions. The ProGRP(31-98) values were not correlated to NSE values in carcinomatous pleurisy due to SCLC. The determination of ProGRP(31-98) in pleural effusions will be helpful for diagnosing carcinomatous pleurisy due to SCLC.

Biomarkers, Tumor↗
PubMed1996

Multiple function of macrophage scavenger receptors mediated by fibrous coiled coil domains.

Type I and type II macrophage scavenger receptors (MSR) have six structurally distinct domains. MSR are known to mediate a wide range of ligand recognition, endocytosis, phagocytosis and macrophage adhesion. Expression of mutated receptors in various cultured cells and analysis using synthetic peptides indicate that two coiled-coil domains, alpha-helical coiled-coil domain (domain IV) and collagen-like domain (domain V) mediate these functions. Domain IV is essential for the trimerization of MSR and EDTA-resistant adhesion function. Domain V is essential for the wide range of ligand recognition. Cooperation of these two domains is also essential for the cellular function of MSR including pH-dependent ligand dissociation.

Amino Acid Sequence↗
PubMed1996

Progastrin-releasing peptide(31-98) in idiopathic pulmonary fibrosis and sarcoidosis.

Gastrin-releasing peptide (GRP) is present in the lung and functions as a growth factor for bronchial epithelial cells and fibroblasts. GRP may stimulate release of cytokines from alveolar macrophages. However, in interstitial lung diseases, the role of GRP has not been clarified, in part because of the instability of GRP. Progastrin-releasing peptide (ProGRP) molecules are the actual GRP gene products. ProGRP molecules contain common extension peptides(31-98) [ProGRP(31-98)], which are not homologous with other proteins unlike GRP. With the ELISA, we measured ProGRP(31-98) concentrations in sera and bronchoalveolar lavage (BAL) fluids from patients with sarcoidosis and idiopathic pulmonary fibrosis (IPF). Significant increased ProGRP(31-98) concentrations were found in sera and BAL fluids from patients with IPF or sarcoidosis when compared with healthy subjects. Serum ProGRP(31-98) values significantly correlated with BAL fluid ProGRP(31-98) values. In IPF and sarcoidosis, the release of the actual GRP gene products is increased in the lung and the bloodstream, and GRP may play a role during the processes of inflammation and remodeling in interstitial lung diseases.

Adolescent↗