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Biomedical subjects

H Itaya

Publications and source records attributed to H Itaya.

At least 19 recordsLinked to original sources
PubMed2006

Secretion of human epidermal growth factor by Corynebacterium glutamicum.

AIMS: To examine the secretion of human epidermal growth factor (hEGF) by Corynebacterium glutamicum. METHODS AND RESULTS: We recently showed that a novel protein-secretion system in C. glutamicum could produce Streptomyces mobaraensis transglutaminase. In the present study, the industrially important protein hEGF was secreted into the culture medium in a fully active form by C. glutamicum and accumulated at a rate of up to 156 mg l(-1) day(-1). CONCLUSIONS: These results demonstrated that the hEGF protein could be secreted in an active form by C. glutamicum. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data confirmed that the pharmaceutically important human protein hEGF could be efficiently secreted in an active form by the C. glutamicum protein-expression system. Moreover, we demonstrated that this bacterium has potential as a host for the industrial-scale production of human proteins.

Blotting, Western↗
PubMed2001

Desferrioxamine, an iron chelator, upregulates cyclooxygenase-2 expression and prostaglandin production in a human macrophage cell line.

Prostaglandins (PGs) play regulatory roles in a variety of physiological and pathological processes, including the immune response, cytoprotection and inflammation. Desferrioxamine (DFX), an iron chelator, is known to reduce free radical-mediated cell injury and to upregulate certain inflammatory mediators. We investigated the effects of DFX on the production of PGs and the expression of cyclooxygenase-2 (COX-2), the rate-limiting enzyme in the synthesis of PGs, using a human macrophage cell line, U937. Our results showed that COX-2 expression and PGE(2) production are upregulated by DFX treatment and that this upregulation is dependent on both COX-2 promoter activity and alteration of mRNA stability. COX-2 promoter activity may be, at least in part, mediated by activation of the extracellular signal-regulated kinase pathway. These findings suggest that iron metabolism may regulate inflammatory processes by modulating PGs as well as other inflammatory mediators.

Binding Sites↗
PubMed2001

Basic fibroblast growth factor inhibits choriocapillaris atrophy in rabbit.

PURPOSE: To examine the effect of basic fibroblast growth factor on induced choriocapillaris atrophy in vivo. METHODS: Choriocapillaris atrophy was surgically induced in rabbits by a hydraulic retinal detachment followed by debridement of the retinal pigment epithelium under the detached retina. Three concentrations of basic fibroblast growth factor (0.1 microg/0.1 ml, 1 microg/0.1 ml, or 5 microg/0.1 ml) were injected into the subretinal space and into the vitreous cavity 1, 3, and 5 days after the surgery. For control, only Tris buffer was injected in the same manner. The rabbits were euthanized 7 days after the surgery. Choroidal vascular casts were made and examined by scanning electron microscopy. The choriocapillaris atrophy was quantified by computer-assisted image analysis of photographs of the choriocapillaries. The area of the choriocapillaris and number of intercapillary spaces in the choriocapillaris that corresponded to the density of the capillary network were measured. RESULTS: The average area of the choriocapillaris in the eyes treated with 1 microg/0.1 ml of basic fibroblast growth factor was significantly larger at 75.1 +/- 3.0% than that in the control eyes at 67.2 +/- 5.6% (P =.021). The average area of the choriocapillaris in the 0.1 microg/0.1 ml of basic fibroblast growth factor group was not statistically different from the control. The number of intercapillary spaces of the choriocapillaris was 132 +/- 12 in the 0.1 microg/0.1 ml of basic fibroblast growth factor group, 124 +/- 46 in the 1 microg/0.1 ml of basic fibroblast growth factor group, and 75 +/- 14 in the control group. The higher number of spaces in the treated group was statistically significant (P =.026). CONCLUSIONS: Basic fibroblast growth factor decreased the atrophy of the choriocapillaris after removal of the retinal pigment epithelium in rabbit eyes. These results suggest that basic fibroblast growth factor may play a role in the survival of the choriocapillaris in vivo.

Animals↗
PubMed2001

Expression of vascular endothelial growth factor in human monocyte/macrophages stimulated with lipopolysaccharide.

Vascular endothelial growth factor (VEGF) is a mitogen for endothelial cells. We have studied the production of VEGF by human macrophages in response to lipopolysaccharide (LPS). Macrophages stimulated with LPS expressed VEGF mRNA and protein in concentration- and time-dependent manners. The LPS-induced expression of VEGF was inhibited by cycloheximide pretreatment, which suggested that synthesis of certain factor(s) is required for the LPS activity. The induction of VEGF was also suppressed by SB203580, an inhibitor of p38 mitogen-activated protein (MAP) kinase. These results suggest that the LPS-induced VEGF expression depends on the p38-mediated expression of c-Jun, which constitutes the AP-1 complex and binds to the AP-1 site in the VEGF promoter. Pretreatment of the cells with dexamethasone did not affect the LPS-induced upregulation of VEGF mRNA but strongly inhibited VEGF protein production, and the involvement of posttranscriptional regulation on VEGF expression by dexamethasone was suggested. The conditioned medium of LPS-stimulated macrophages enhanced the growth of cultured endothelial cells and it was inhibited by an antibody against VEGF. We conclude that macrophages produce VEGF in response to the stimulation with LPS, which may be partly mediated by the p38 MAP kinase pathway.

Cells, Cultured↗
PubMed2001

[Effects of topical prostaglandin analogues on the aqueous flare intensity in rabbit eyes at an early phase of endotoxin-induced uveitis].

PURPOSE: We examined the effects of prostaglandin analogues on the blood-aqueous barrier(BAB) permeability in rabbit eyes at an early phase of endotoxin-induced uveitis(EIU). SUBJECTS AND METHODS: One drop of 0.005% latanoprost or 0.12% unoprostone were applied to rabbit eyes. Escherichia coli lipopolysaccharides were injected to induce uveitis. The changes in flare intensity in normal eyes and EIU eyes after application of eye drops were evaluated. The effect of cyclooxygenase inhibitor on the flare intensity changes caused by the application of unoprostone was also examined. RESULTS: Flare intensity increased significantly after a single instillation of unoprostone, and the increase was not prevented by pretreatment with cyclooxygenase inhibitor. In eyes with EIU, unoprostone caused an additional increase of flare intensity to uveitis induced flare change. Latanoprost had no effects on BAB in eyes with normal and with uveitic conditions. CONCLUSION: Latanoprost and unoprostone did not cause an excessive inflammatory reaction in rabbit eyes at an early phase of EIU.

Animals↗
PubMed2000

Expression of tumor necrosis factor-alpha in cultured human endothelial cells stimulated with lipopolysaccharide or interleukin-1alpha.

Tumor-necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine with a wide variety of biological effects. The most important source of this cytokine is monocytes/macrophages. It is a potent agonist in the activation of endothelial cells; however, the precise role of endothelial cells as a source of TNF-alpha is not known. In the present study, we addressed the possibility that TNF-alpha is produced by cultured human umbilical vein endothelial cells (HUVEC) stimulated with factors such as lipopolysaccharide (LPS) or interleukin-1alpha (IL-1alpha). LPS and IL-1alpha induced expression of TNF-alpha mRNA in HUVEC. IL-1alpha induced expression and secretion of TNF-alpha protein, but LPS did not induce production of TNF-alpha protein. Most of the TNF-alpha protein in cell lysate was found in the membrane fraction. The mRNA for TNF-alpha-converting enzyme (TACE) was expressed in unstimulated HUVEC, and its level was not altered by treatment with LPS or IL-1alpha. Transfection of HUVEC with full-length cDNA encoding the precursor TNF-alpha enhanced secretion of TNF-alpha protein by these cells, and treatment of the cells with a TACE inhibitor reduced the secretion. These results suggest that HUVEC produce TNF-alpha and have TACE activity. Secreted TNF-alpha may be involved in autocrine activation of endothelial cells, and TNF-alpha retained in cell membrane may serve as a juxtacrine system to activate target cells on the endothelial surface.

ADAM Proteins↗
PubMed2000

Expression of vascular endothelial growth factor in human umbilical vein endothelial cells stimulated with interleukin-1alpha--an autocrine regulation of angiogenesis and inflammatory reactions.

Vascular endothelial growth factor (VEGF) is a specific mitogen for endothelial cells. We studied the production of VEGF by human umbilical vein endothelial cells (HUVEC) and smooth muscle cells (SMC) in response to the stimulation with interleukin-1alpha (IL-1alpha). HUVEC expressed VEGF mRNA in response to IL-1alpha in dose- and time-dependent manners. In HUVEC VEGF protein was detected only in cell lysates whereas in SMC most of the VEGF protein was detected in the conditioned medium. Immunofluorescent staining also confirmed the cell-associated VEGF in HUVEC. IL-1alpha also induced the expression of mRNA for IL-1alpha itself in HUVEC. Cycloheximide treatment of HUVEC slightly inhibited the IL-1alpha-induced expression of VEGF mRNA, and IL-1alpha may mediate, at least in part, VEGF expression in response to IL-1alpha. The growth of HUVEC stimulated with IL-1alpha was inhibited by a neutralizing antibody against VEGF. We conclude that IL-1alpha and VEGF may play an important role in autocrine growth regulation of HUVEC.

Cell Culture Techniques↗
PubMed1998

[Reoperative coronary artery bypass grafting without cardiopulmonary bypass].

Between October 1995 and February 1997, 2 men and 4 women aged 53 to 75 years (mean, 66.3) underwent reoperative coronary artery bypass grafting without cardiopulmonary bypass. Isolated reoperative circumflex or intermediate artery bypass was performed through a left thoracotomy (n = 2), reoperative bypass to the left anterior descending coronary artery was performed through a median sternotomy (n = 3), and bypass to the right coronary artery was performed through an upper median laparotomy (n = 1). Single coronary bypass grafting utilizing arterial grafts (left internal thoracic artery: 3, right gastroepiploic artery: 3) was performed in all cases. There were no operative deaths. All cases required neither cathecolamine nor intraaortic balloon pumping). Peri/post operative blood transfusion was necessary in only one case. Postoperative coronary angiography revealed that the 6 arterial grafts were patent. Reoperative coronary artery bypass grafting without cardiopulmonary bypass can be performed with low perioperative morbidity and mortality, easy postoperative management, satisfactory graft patency, and good symptomatic improvement.

Aged↗
PubMed1998

A mutation in plasma platelet-activating factor acetylhydrolase (Val279Phe) is a genetic risk factor for cerebral hemorrhage but not for hypertension.

Platelet-activating factor (PAF) acetylhydrolase is an enzyme that inactivates PAF. Deficiency of this enzyme is caused by a missense mutation in the gene. We previously found a higher prevalence of this mutation in patients with ischemic stroke. This fact suggests that the mutation might enhance the risk for stroke through its association with hypertension. We have addressed this hypothesis by analyzing the prevalence of the mutation in hypertension. We studied 138 patients with essential hypertension, 99 patients with brain hemorrhage, and 270 healthy controls. Genomic DNA was analyzed for the mutant allele by the polymerase-chain reaction. The prevalence of the mutation was 29.3% (27.4% heterozygotes and 1.9% homozygotes) in controls and 36.2% in hypertensives and the difference was not significant. The prevalence in patients with brain hemorrhage was significantly higher than the control: 32.6% heterozygotes and 6.1% homozygotes (p <0.05). PAF acetylhydrolase deficiency may be a genetic risk factor for vascular diseases.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗
PubMed1977

Purification of rat intestinal receptor for intrinsic factor-vitamin B-12 complex by affinity chromatography.

Rat intrinsic factor was bound to vitamin B-12-Sepharose to produce intrinsic factor-vitamin B-12-Sepharose. Intestinal receptor for intrinsic factor-vitamin B-12 complex was purified from rat ileal extract by affinity chromatography using the intrinsic factor-vitamin B-12-Sepharose as an affinity adsorbent with recovery of 48.5% and specific activity increased 335 fold of original sample.

Animals↗
PubMed1977

Ultrastructural investigation of the effect of mitomycin C on the rat exocrine pancreas.

In order to clarify the pathophysiology of digestive disorders which are caused with anticancer agents, Mitomycin C was intravenously administrated to rats and the ultrastructure of the pancreas was studied. The alteration of acinar cells after under 4 daily administrations of 1.0 mg/Kg of Mitomycin C was not remarkable and in an early stage returned to normal structure. In above 8 daily administrations of 1.0 mg/Kg of Mitomycin C, however, pronounced degeneration of acinar cells was induced and acinar cells did not recover to the previous level, but die within one month. The ultrastructural changes induced by Mitomycin C were mainly aggregation of chromatin in the nuclei, tubularly dilatation of the rough endoplasmic reticulum, and swelling of the mitochondria. It was surmised that the biosynthesis and supply of protein such as digestive enzymes were not amply carried on; hence, the ehcmotherapy could give rise to severe digestion disorders. It appeared necessary to further study the dosage and dosage schedule of the anticancer agents, along with the necessity for taking ample care of patients presenting such disorders.

Animals↗