Biomedical subjects

T Kodama

Publications and source records attributed to T Kodama.

At least 433 records · Page 24Linked to original sources

PubMed1996

[Perioperative managements for postoperative severe infections in compromised host].

The incidence of postoperative infections, especially due to multi-drug resistant strains such as Pseudomonas sp., Enterococcus sp., and Methicillin resistant Staphylococcus aureus (MRSA), is high in compromised hosts. Among them, respiratory infection, catheter sepsis, and drug-associated enteritis are frequently observed and respiratory infection is liable to fall into serious illness. These infections have characteristics in causative organisms. Pseudomonas aeruginosa or MRSA are frequently isolated in respiratory infections and Candida or coagulase-negative staphylococcus are frequently isolated in catheter sepsis. G-test in addition to blood culture is necessary for early diagnosis of Candida sepsis, vancomycin should be administered in early phase of antibiotic-associated enteritis, since this infection is usually caused by MRSA or Clostridium difficile and frequently falls into serious illness. The patients with protein-calorie malnutrition, liver cirrhosis, renal failure, diabetes melitis, administration of anticancer drugs and/or radiation therapy, serious injury, or severe operative stress are considered to be compromised hosts in surgical field, and the adequate perioperative managements according to these disorders should be carried out against postoperative infections.

Bacterial Infections↗

PubMed1995

Sequencing and characterization of the downstream region of the genes encoding nitrite reductase and cytochrome c-551 (nirSM) from Pseudomonas aeruginosa: identification of the gene necessary for biosynthesis of heme d1.

The nirC and nirF genes were identified downstream from nirSM, the structural genes encoding nitrite reductase (NIR) and cytochrome c-551 from Pseudomonas aeruginosa (Pa). The nirC gene encodes a probable c-type cytochrome with a signal sequence for membrane translocation. The nirF gene codes for a protein of 392 amino acids. A nirF mutant of Pa, constructed by marker exchange mutagenesis, synthesized an inactive NIR protein whose activity was restored by adding purified heme d1. The mutant strain produced an active NIR, when it was transformed by a broad-host-range plasmid carrying nirF. These results showed that the product of nirF was essential for the biosynthesis of heme d1 in Pa.

Amino Acid Sequence↗

PubMed1995

Time course of the induction of VGF mRNA in the dorsal vagal complex in rats with cysteamine-induced peptic ulcers.

The time course of induction of VGF mRNA in the dorsal vagal complex of the medulla oblongata was investigated in rats with duodenal ulcer induced with cysteamine by in situ hybridization histochemistry. In control rats, weak VGF mRNA signals were detected in a few neurons in the nucleus tractus solitarii and dorsal motor nucleus of vagus. After the cysteamine administration (450 mg/kg, s.c.), VGF mRNA signals began to increase after 3 h, reached at peak level at 12 h, and decreased slightly at 24 h, but remained high after 48 h. The time course of duodenal ulcer score was absent at 3 h, very low at 6 h, about grade 1 at 12 h, and grade 2 or more at 24 and 48 h. The present results support the hypothesis that the increase of the central neuronal activity of the vagus nerve precedes ulcer generation in the duodenum.

Analysis of Variance↗

PubMed1995

Hampered expression of isoaspartyl protein carboxyl methyltransferase gene in the human cataractous lens.

Isoaspartyl protein carboxyl methyltransferase (PIMT) is implicated in the repair of age-damaged proteins by converting altered aspartic acid residues to normal L-aspartic acid residues. Northern blot and reverse transcription (RT)-PCR analyses have revealed that PIMT gene expression in the human lens is detected exclusively in epithelial cells, and that the mRNA levels in cataractous lens epithelia are significantly lower than those in normal age-matched lens tissue. These results suggest that PIMT may play a vital role in maintaining the clarity of the lens and preventing cataract formation.

Aspartic Acid↗

PubMed1995

Expression of the nir and nor genes for denitrification of Pseudomonas aeruginosa requires a novel CRP/FNR-related transcriptional regulator, DNR, in addition to ANR.

A gene, designated dnr, was identified in the vicinity of the structural genes for nitrite reductase (nirS) and nitric oxide reductase (norCB), and the gene for activation of the reductases (nirQ) from Pseudomonas aeruginosa. It encodes a protein of 227 amino acids homologous with the CRP/FNR-family transcriptional regulators. Promoter activities for nirS, nirQ and norCB were considerably reduced in the dnr mutant as well as in the mutant of anr, the other fnr-like regulatory gene from P. aeruginosa. This is the first finding that two CRP/FNR-related regulators are involved in denitrification in one strain.

Bacterial Proteins↗

PubMed1995

Telomerase activity in gastric cancer.

Although many genetic alterations have been reported in gastric cancer, it is not known whether all gastric tumors are capable of indefinite proliferative potential, e.g., immortality. The expression of telomerase and stabilization of telomeres are concomitant with the attainment of immortality in tumor cells; thus, the measurement of telomerase activity in clinically obtained tumor samples may provide important information useful both as a diagnostic marker to detect immortal cancer cells in clinical materials and as a prognostic indicator of patient outcome. Telomerase activity was analyzed in 66 primary gastric cancers with the use of a PCR-based assay. The majority of tumors (85%) displayed telomerase activity, but telomerase was undetectable in 10 tumors (15%), 8 of which were early stage tumors. Most of the tumors with telomerase activity were large and of advanced stages, including metastases. Survival rate of patients of tumors with detectable telomerase activity was significantly shorter than that of those without telomerase activity. Alterations of telomere length (reduced/elongated terminal restriction fragments) were detected in 14 of 66 (21%) gastric cancers, and all 14 had telomerase activity. Cellular DNA contents revealed that all 22 aneuploid tumors had detectable telomerase activity. The present results indicate that telomerase activation may be required as a critical step in the multigenetic process of tumorigenesis, and that telomerase is frequently but not always activated as a late event in gastric cancer progression.

Base Sequence↗

PubMed1995

Macrophage scavenger receptor mediates the endocytic uptake and degradation of advanced glycation end products of the Maillard reaction.

Modification of proteins by long-term incubation with glucose leads to the formation of advanced glycation end products (AGE). Recent immunological demonstration of the presence of AGE proteins in several human tissues suggests that they may be involved in aging, diabetic complications and atherosclerosis. AGE proteins are taken up by macrophages via the AGE receptor, which is similar to the macrophage scavenger receptor (MSR). In the present study, we examined whether MSR could mediate the endocytic uptake of AGE proteins by using Chinese hamster ovary (CHO) cells overexpressing bovine type II MSR (CHO-SRII). 125I-labelled AGE bovine serum albumin (125I-AGE-BSA) as well as 125I-acetylated low-density lipoprotein (125I-acetyl-LDL) underwent endocytic degradation by CHO-SRII cells, but not by control CHO cells. Endocytic degradation of 125I-acetyl-LDL and 125I-AGE-BSA by CHO-SRII cells was significantly inhibited by unlabeled AGE-BSA, as well as by acetyl-LDL. Immunoelectron microscopic studies using both AGE-BSA conjugated with gold particles and anti-(bovine MSR) antibody (D2) revealed co-localization of gold particles and the reactive sites for the antibody at coated pits of plasma membranes as well as in endosomes. These results clearly show that MSR mediates the endocytic uptake and degradation of AGE proteins, suggesting a new role of MSR in biological recognition of AGE in vivo.

Animals↗

PubMed1995

The structural genes for nitric oxide reductase from Pseudomonas aeruginosa.

The genes for nitric oxide reductase (norCB) from Pseudomonas aeruginosa were identified and sequenced. They are located about 2 kb upstream of nirS, the structural gene for nitrite reductase. norC and norB encode cytochrome c (16 kDa) and cytochrome b (52 kDa) subunits of the enzyme, respectively. norCB is immediately followed by an open reading frame encoding a protein of 612 residues.

Amino Acid Sequence↗

PubMed1995

The molecular mechanism of the induction of the low density lipoprotein receptor by chenodeoxycholic acid in cultured human cells.

In a cultured human hepatoblastoma cell line, Hep G2, chenodeoxycholic acid (CDCA) induced LDL receptor mRNA levels approximately 4 fold and mRNA levels for HMG-CoA reductase and HMG-CoA synthase two fold. In contrast, the mRNA levels for mevalonate kinase, farnesyl pyrophosphate synthase and squalene synthase were not changed significantly. The pattern of the induction of the sterol-sensitive genes was similar to the induction by N-acetyl-leucyl-leucyl-norleucinal (ALLN), an SREBP degradation inhibitor, suggesting that CDCA may increase mature SREBPs. CDCA could inhibit the 25-hydroxycholesterol mediated inactivation of SREBP without affecting mRNA levels of SREBPs. These results suggest that CDCA can affect sterol metabolism by a novel mechanism involving the inhibition of the oxysterol-mediated inactivation of SREBP.

Alkyl and Aryl Transferases↗

PubMed1995

Genes encoding RubisCO in Pseudomonas hydrogenothermophila are followed by a novel cbbQ gene similar to nirQ of the denitrification gene cluster from Pseudomonas species.

The cbbL and cbbS genes, encoding ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), were cloned and sequenced from a thermophilic hydrogen-oxidizing bacterium, Pseudomonas hydrogenothermophila strain TH-1. The cbbL gene encoded a 474-amino-acid (aa) protein (53,285 Da); cbbS encoded a 124-aa protein (14,656 Da). An ORF found downstream from the cbbLS genes encoded a 267-aa protein (29,565 Da) which had no similarity to cbbX located downstream from cbbLS from Alcaligenes eutrophus and Xanthobacter flavus. This gene, called cbbQ, was highly similar to the nirQ gene of the denitrification gene cluster from P. aeruginosa and P. stutzeri.

Alcaligenes↗

PubMed1995

A helper T-cell antigen enhances generation of hepatitis C virus-specific cytotoxic T lymphocytes in vitro.

A T-cell helper for generation of hepatitis C virus-specific cytotoxic T lymphocytes was studied in three patients with chronic hepatitis C. In all three, human leukocyte antigen B44-restricted cytotoxic T lymphocytes recognizing an epitope in hepatitis C virus nucleocapsid protein residues 81-100 were generated from the peripheral blood lymphocytes by repeated stimulation with a synthetic hepatitis C virus nucleocapsid peptide. The proliferative response of peripheral blood lymphocytes to hepatitis C virus nucleocapsid protein residues 1-120 was observed in one patient, and was ascribed to CD4+ T cells. The helper T cells recognized a major epitope in residues 21-40 and a minor epitope(s) in residues 81-110. They produced interferon gamma, but interleukin 4 was not detectable in the T-helper cell culture supernatants. The hepatitis C virus nucleocapsid protein residues 1-120 and the major helper T-cell epitope enhanced generation of hepatitis C virus-specific cytotoxic T lymphocytes in vitro, although the protein alone did not generate them. In the other two patients, the protein did not enhance generation of hepatitis C virus-specific cytotoxic T lymphocytes in vitro. The results suggest that a hepatitis C virus-specific helper T-cell epitope is helpful for inducing a strong specific cytotoxic T-lymphocyte response.

Amino Acid Sequence↗

PubMed1995

Localization of advanced glycation end products of Maillard reaction in bovine tissues and their endocytosis by macrophage scavenger receptors.

In aged bovines, the accumulation of advanced glycation end-products (AGEs) in macrophages, endothelial cells, adventitial cells, or pericytes; epithelial or parenchymal cells of some organs such as the liver, adrenals, and kidneys; neuronal cells in the brain; and extracellular matrix was demonstrated by immunohistochemistry using anti-AGE monoclonal antibody 6D12. Immunoelectron microscopy demonstrated the localization of AGEs in the endosomal and lysosomal compartments of various types of cell and in the extracellular matrix. By biochemical characterization of the interaction of AGEs with bovine alveolar macrophages using [125I]AGE-bovine serum albumin (BSA), the cell association and subsequent endocytic degradation of [125I]AGE-BSA were confirmed. To investigate the possible participation of scavenger receptors in the endocytosis of AGEs, these cells were incubated with AGE-BSA conjugated with colloidal gold particles (AGE-BSA-Au particles) and examined by immunoelectron microscopy with a monoclonal antibody for bovine macrophage scavenger receptors, D2. In these macrophages, AGE-BSA-Au particles were bound to the D2-positive scavenger receptors on the surface membrane, endocytosed, and directed to secondary lysosomes. The scavenger receptors were dissociated from the ligands in late endosomes and recycled via a trans-Golgi system to the cell surface membrane. These data suggest that scavenger receptors participate in the endocytic process of AGEs by macrophages.

Aging↗

PubMed1995

The interaction between endothelium-derived relaxing factor (EDRF) and eicosanoids in the regulation of the mesenteric microcirculation.

Locally produced eicosanoids and endothelium-derived factors are believed to be the mediators of vascular tone of various vascular beds including the mesentery. Using a small vessel isometric myograph which allows direct measurement of microvascular reactivity, the interaction of eicosanoids and endothelium-derived relaxing factor (EDRF) in regulating vascular tone of mesenteric microcirculation of the rat was characterized. The microvascular response to various vasoactive agents before and after inhibition of prostacyclin production with indomethacin (INDO, 5 microM) and inhibition of EDRF synthesis with N omega-nitro-L-arginine methyl ester (L-NAME, 50 microM) was compared. Analysis of dose-response curves for prostaglandin F2 alpha (PGF2 alpha), U46619, a stable thromboxane analog, and norepinephrine (NE) after pretreatment with INDO demonstrated that inhibition of endogenous eicosanoids significantly attenuated the vasoconstrictor response to PGF2 alpha and U46619 but not to NE. Inhibition of EDRF synthesis with L-NAME potentiated the vasoconstrictor response to PGF2 alpha, U46619, and NE. These results suggest that EDRF acts as the primary mediator of vasodilator tone in the mesenteric microcirculation rather than vasodilator cyclooxygenase products such as prostacyclin. It also appears that the vasoconstrictor action of PGF2 alpha and U46619 may be mediated by a release of an endogenous indomethacin-sensitive factor.

Animals↗

PubMed1995

Immunohistochemical localization of epidermal growth factor receptor and epithelial antigen in tumors of the human conjunctiva, eyelid, lacrimal gland, and orbit.

BACKGROUND: Increased numbers of epidermal growth factor (EGF) receptors are observed in squamous cell carcinomas of human lung, head, neck, and cervix. We studied the presence of EGF receptors and epithelial antigen in some ophthalmic lesions. METHODS: Immunohistochemical staining for EGF receptors was assessed in tumors of human conjunctiva, eyelid, lacrimal glands, and orbit with monoclonal antibodies (EGF-R1 and clone 29.1). Reactivity of Ber-EP4, which recognizes epithelial antigen, was also examined. RESULTS: Strong staining of EGF-R1 and clone 29.1 and weak to moderate staining of Ber-EP4 were demonstrated in conjunctival squamous cell carcinomas. Cell membranes of conjunctival papilloma were moderately or strongly stained with these antibodies. Ductal components in sebaceous gland adenoma of the eyelid and pleomorphic adenoma of the lacrimal gland were positively stained. The antibodies did not bind to reactive lymphoid hyperplasia of the orbit and Wegener's granulomatosis. Relatively good correlation for immunostaining reaction was observed among EGF-R1, clone 29.1, and Ber-EP4 in each tumor. CONCLUSION: Immunostaining using EGF-R1, clone 29.1, and Ber-EP4 may be useful in differentiating epithelial tumors from non-epithelial lesions. Strong immunostaining for EGF receptor may be the hallmark of epidermoid malignancy.

Adenoma↗

PubMed1995

Severity and predicted outcome of postoperative Pseudomonas aeruginosa infections.

The severity and predicted outcome of postoperative Pseudomonas aeruginosa (P. aeruginosa) infections (PPAI) was evaluated using a severity scoring system based on a simplification and modification of the APACHE II system. A total of 86 patients in whom P. aeruginosa was isolated from various sources were examined. PPAI developed in 50 patients, resulting in an overall mortality rate of 24%. An increased severity score (SS) correlated with an increased risk of developing PPAI. Thus, PPAI developed in 33% of the patients with an SS of 0-1, in 66.7% of those with an SS of 2-3, and in 100% of those with an SS of 6 or higher. Moreover, the mortality rate of the patients with an initial score of 6 or higher was 50%. The mean (+/- SD) initial severity score was 5.4 +/- 2.9 for survivors and 2.9 +/- 2.6 for nonsurvivors (P < 0.01). In the patients who subsequently died, the SS remained high throughout the clinical course despite therapy, whereas in the survivors the SS decreased progressively, reflecting a favorable clinical course. These results suggest that our severity scoring system was useful for predicting outcome and monitoring the response of PPAI to therapy.

Adult↗

PubMed1995

A case of gastric antral vascular ectasia--increase of neuroendocrine cells in the antrum.

We report an 82-year-old woman with severe iron deficiency anemia who was found to have gastric antral vascular ectasia (GAVE). As she required repeated blood transfusion for the anemia and did not respond to various medical treatments, she was referred for antrectomy. The pathogenesis of GAVE is still obscure and may involve many factors. In our patient, immunohistochemical studies of the resected stomach disclosed a marked increase of neuroendocrine cells. The majority of these hyperplastic neuroendocrine cells, furthermore, showed immunoreactivity for 5-hydroxytryptamine (serotonin). These findings suggest that neuroendocrine mediators, serotonin in particular, may have been responsible for the local vasodilation.

Aged↗

PubMed1995

Oxidized cholesterol modulates age-related change in lipid metabolism in rats.

For three weeks, male Sprague-Dawley rats at either four weeks (young) or eight months (adult) of age were pair-fed one of the purified diets free of or containing either 0.2% of oxidized cholesterol mixture (cholesterol oxidation products) or 0.2% of cholesterol. Although the food intake was similar, dietary oxidized cholesterol lowered body weight gain in young rats, but did not increase relative liver weight, in contrast to the enlargement seen with dietary cholesterol. Oxidized cholesterol, compared to cholesterol, tended to reduce the activity of hepatic 3-hydroxy-3-methylglutaryl CoA reductase and cholesterol 7 alpha-hydroxylase, particularly the latter in aged rats, and prevented the rise in the concentration of liver cholesterol at both ages. It also tended to increase the activity of hepatic delta 6 desaturase, particularly in young rats. Moreover, oxidized cholesterol in relation to cholesterol influenced liver and serum lipid concentrations in different ways, and increased lipid peroxidation at both ages. The ratio of splenic CD4+/CD8+ T-lymphocytes increased with age, but the influence of cholesterol and oxidized cholesterol was comparable. Thus, oxidized cholesterol may specifically disturb growth and age-related changes in the lipid metabolism in rats.

Aging↗

PubMed1995

HLA-linked susceptibility and resistance genes in Crohn's disease.

BACKGROUND & AIMS: Previous studies have shown a positive association of HLA-DR4-DQ4 with Crohn's disease in the Japanese population, but the association between Crohn's disease and HLA genes has yet to be fully elucidated. The aim of this study was to determine the Crohn's disease/HLA association using a DNA typing method. METHODS: A total of 90 unrelated patients with Crohn's disease and 336 healthy controls were typed for HLA class II genes including DP using DNA typing with the polymerase chain reaction-sequence-specific oligonucleotide probes method. RESULTS: Allelic analysis showed that DRB1*0405, DRB1*0410, DQA1*03, DQB1*0401, and DQB1*0402 are positively associated and DRB1*1501, DRB1*1302, and DQB1*0602 negatively associated with Crohn's disease. DP genes showed no significant association with Crohn's disease. Haplotype analysis showed positive associations with DRB1*0405-DQA1*03-DQB1*0401, DRB1*0410-DQA1*03-DQB1* 0402, and DRB1*0802-DQA1*03-BQB1-0402 haplotypes and negative associations with DRB1*1501-DQA1*0102-DQB1*0602 and DRB1*1302-DQA1*0102-DQB1*0604 haplotypes. CONCLUSIONS: In Crohn's disease in the Japanese population, the HLA-linked disease susceptibility gene is primarily associated with DQB1*04, in which leucine at the 56th position is a unique amino acid, and the disease resistance allele is suggested to be DQA1*0102.

Base Sequence↗