Biomedical subjects

K Uchida

Publications and source records attributed to K Uchida.

At least 127 records · Page 7Linked to original sources

PubMed2001

Medium-chain fatty acids stimulate interleukin-8 production in Caco-2 cells with different mechanisms from long-chain fatty acids.

BACKGROUND AND AIM: It has been suggested that dietary fat exacerbates intestinal inflammation. We investigated the effect of fatty acids on interleukin (IL)-8 production in a human intestinal epithelial cell line (Caco-2). METHODS: The cells were cultured as monolayers on microporous membranes in culture inserts. Oleic acid (OA), capric acid (CA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) were applied to the apical compartment of Caco-2 cell monolayers. The concentration of IL-8 in the basolateral medium was measured by using enzyme-linked immunosorbent assay, and the expression of IL-8 mRNA was measured by using competitive reverse transcription--polymerase chain reaction. Protein kinase C inhibitors (GF109203X and calphostin C) and H-7 (a protein kinase inhibitor) were used to study the mechanisms by which IL-8 production is stimulated. RESULTS: Both OA and CA enhanced IL-8 production (approximately fivefold), whereas DHA and EPA did not. Both OA and CA also enhanced IL-1-induced IL-8 production. The onset of OA-induced IL-8 production was delayed compared with that of CA-induced IL-8 production. Both OA and CA enhanced IL-8 mRNA expression (approximately fivefold) after 6 and 3 h, respectively. The protein kinase inhibitor (H-7) reduced both OA- and CA-induced IL-8 production by 88.0 and 85.9%, respectively. The protein kinase C inhibitors (GF109203X and calphostin C) reduced OA-induced IL-8 production by 29.3 and 54.5%, respectively, but showed no effect on CA-induced IL-8 production. CONCLUSIONS: These findings suggest that not only OA but also CA stimulates IL-8 production in intestinal epithelial cells, and the mechanisms of action differ between OA and CA.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed2001

More than 1,000 cases of total parathyroidectomy with forearm autograft for renal hyperparathyroidism.

Between March 1981 and December 2000, we performed 1,053 total parathyroidectomies with forearm autograft for advanced renal hyperparathyroidism (HPT). Based on histopathologic and pathophysiologic investigations, surgical treatment should be considered when parathyroid glands show nodular hyperplasia. Measuring parathyroid volume by ultrasonography was useful to detect nodular glands and to determine surgical indications. The clinical effect of parathyroidectomy on the symptoms and biochemical variables was striking. Skeletal deformity, progressive bone loss, and vessel calcification leading to high mortality risk could not be alleviated by even successful surgery, however. To prevent cardiovascular complications, parathyroidectomy should be performed in the relatively early stage of renal HPT. Total parathyroidectomy with forearm autograft is a suitable procedure for renal HPT, especially in patients who require long-term hemodialysis. For surgeons, it is important to remove all parathyroid glands, including supernumerary glands, at the initial operation and to choose adequate parathyroid tissue for the autograft to prevent persistent and recurrent HPT. Although the risk of graft-dependent recurrent HPT is not negligible, enlarged transplanted parathyroid tissue can be removed easily and noninvasively from the forearm under local anesthesia. There is no risk of hypofunction of the autograft.

Adult↗

PubMed2001

Osteoprotegerin levels before and after renal transplantation.

Osteoprotegerin (OPG) is a newly identified glycoprotein that belongs to the tumor necrosis factor receptor superfamily and regulates bone mass by inhibiting osteoclastic bone resorption. The regulatory mechanism of OPG is still unclear after successful renal transplantation (RTX), however, resulting in resolution of uremia. The present study was designed to clarify the potential role of OPG in uremia and after RTX under immunosuppressive therapy. We evaluated circulating OPG levels by measuring them before and after RTX (postoperative days 2, 14, and 28). Our protocol of immunosuppressive drugs was dual therapy using cyclosporine and steroids. Serum OPG was quantitated using enzyme-linked immunosorbent assay. After successful RTX, serum OPG levels decreased significantly on day 14 and day 28 compared with the baseline level (P < 0.05). Creatinine clearance dramatically increased until day 14 and decreased thereafter. Serum OPG declines for the first 2 weeks after RTX owing to functioning allograft and decreases again for the next 2 weeks because of steroids and possible immunosuppressive agents.

Adult↗

PubMed2001

A critical role for IL-7R signaling in the development of Helicobacter felis-induced gastritis in mice.

BACKGROUND & AIMS: Interleukin (IL)-7 is a critical cytokine in the development of T and B cells and is involved in gastrointestinal pathophysiology. The aim of this study was to investigate the involvement of IL-7 receptor (IL-7R) signaling in Helicobacter-induced gastritis. METHODS: C57BL/6 mice (n = 40) were inoculated with H. felis. Twenty mice were injected intraperitoneally with neutralizing IL-7R antibody (A7R34) every seventh day for 3 months. Histology, serum anti-H. felis antibody, and gene expression of IL-7, IL-7R, and proinflammatory cytokines in the gastric mucosa were evaluated. RESULTS: Seventeen of 20 (85%) infected mice without A7R34 developed severe atrophic gastritis, whereas there was no gastritis in A7R34-treated infected mice. There was no difference in the serum levels of anti-H. felis antibody between the 2 groups. IL-7, IL-7R, IL-1alpha, tumor necrosis factor alpha, and interferon gamma messenger RNA expressions were up-regulated in control infected mice, whereas only IL-7 messenger RNA was up-regulated in A7R34-treated infected mice. Immunohistochemistry indicated positive cytoplasmic staining of IL-7 in the gastric epithelial cells. CONCLUSIONS: These data suggest a critical role for IL-7 receptor signaling in the development of Helicobacter-induced gastritis in mice.

Animals↗

PubMed2001

Immunohistochemical study of age-dependent brain lesions in mice infected intracerebrally with Kasba (Chuzan) virus.

When Kasba (Chuzan) virus (an orbivirus) was injected intracerebrally into 1-, 2- or 4-week-old mice, non-purulent necrotizing encephalitis developed and the mice showed nervous symptoms and became moribund. The necrotic lesions were more severe in younger animals. In 1-week-old mice, viral titres rose until 7 days post-infection, while in 2- and 4-week-old animals the titres reached a peak on day 3 and then declined gradually. Glial fibrillary acidic protein-positive astrocytes increased in the white matter, hippocampus and subpial area of the cerebral cortex of infected animals, and lectin-RCA-1-positive cells, thought to be microglial cells, increased in the necrotic lesions. The number of these glial cells increased even after viral titres had declined. In this study there were no survivors in any age group, but survival time increased with age.

Age Factors↗

PubMed2001

Suppression of tumourigenicity, and induction of differentiation of the canine mammary tumour cell line MCM-B2 by sodium phenylacetate.

The authors evaluated the cell growth inhibition, reduction of tumourigenicity, and differentiation-inducing effects of sodium phenylacetate (NaPA) on a canine mammary tumour cell line. Treatment of the canine mammary tumour cell line (MCM-B2) with NaPA lead to the arrest of cell growth. Sodium phenylacetate induced changes in the cells to non-malignant characteristics, as indicated by a reduction of colony formation in semi-solid agar and a decrease in tumour formation in athymic mice. Moreover, NaPA induced morphological changes from a spindle-shaped to an epithelial-like appearance, and significant accumulation of lipid droplets in the cytoplasm. Immunohistochemically, these treated cells reacted clearly with the antibody for keratin/cytokeratin. Sodium phenylacetate treatment increased the expression of the milk-specific genes alpha-lactalbumin and beta-casein. The results of this study warrant an evaluation of NaPA in a clinical trial to establish its possible value as adjunctive treatment of malignant canine mammary tumours.

Animals↗

PubMed2001

Successful treatment with steroids of upper gastrointestinal acute graft vs. host disease after hematopoietic stem cell transplantation.

A 39-year-old man with acute myeloid leukemia underwent completely matched related hematopoietic stem cell transplantation. On post-transplantation day 83 he was diagnosed as having upper gastrointestinal graft-versus-host disease (GVHD) by endoscopic examination and pathological examination of endoscopic biopsy specimens, and daily administration of 60 mg of water-soluble prednisolone and 50 mg of cyclosporine was started. After steroid therapy, the symptoms of upper gastrointestinal GVHD disappeared completely and endoscopic findings dramatically improved.

Acute Disease↗

PubMed2001

High concentrations of glucose induce synthesis of argpyrimidine in retinal endothelial cells.

PURPOSE: To determine if high concentrations of glucose applied to cultured bovine retinal endothelial cells (BRE cells) would result in production of intracellular methylglyoxal (MG), and consequently, the synthesis of MG-derived advanced glycation end products (AGEs). METHODS: BRE cells were incubated with 30 mM D-glucose or 30 mM L-glucose for 7 days. Cells incubated with medium that had 5-mM glucose served as controls. Cells were lysed and the lysate was centrifuged to get a supernatant and a pellet fraction. We measured argpyrimidine, a MG-derived fluorescent AGE in the two fractions by a competitive ELISA using a monoclonal antibody. RESULTS: BRE cells incubated with 30 mM D-glucose produced significantly higher (P < 0.05) levels of intracellular MG than control cells or cells incubated with 30 mM L-glucose. Incubation with 30 mM D-glucose significantly (P < 0.05) enhanced the synthesis of argpyrimidine in both supernatant and pellet fractions when compared to control cells. Immunofluorescence studies confirmed results obtained by ELISA and showed higher levels of argpyrimidine in cells incubated with 30 mM D-glucose. CONCLUSION: These results suggest that MG-mediated protein modification can occur in elevated glucose, and might contribute to endothelial cell changes associated with diabetic retinopathy.

Animals↗

PubMed2001

Anticarcinogenic antioxidants as inhibitors against intracellular oxidative stress.

Oxidative stress has been implicated in the pathogenesis of numerous diseases, including cancer. In the present study, the protective effect of natural antioxidants, such as quercetin and tea polyphenols, on intracellular oxidative stress was studied. Here we report a novel function of quercetin and tea polyphenols, as potential inhibitors of 4-hydroxy-2-nonenal (HNE)-induced intracellular oxidative stress and cytotoxicity. In rat liver epithelial RL34 cells, a potent electrophile HNE dramatically induced the productions of reactive oxygen species (ROS), which correlated well with the reduction in cell viability. We found that quercetin and tea polyphenols, such as epigallocatechin gallate and theaflavins and their gallate esters, significantly inhibited the HNE-induced ROS production and cytotoxicity. In addition, HNE induced a transient decrease in the mitochondrial membrane potential (delta psi), which was also retarded by the antioxidants. These data suggest that the antioxidants, such as quercetin and tea polyphenols, are inhibitors against mitochondrial ROS production.

Aldehydes↗

PubMed2001

Serum concentration of hepatocyte growth factor predicts perioperative surgical stress in children.

OBJECTIVE: To find out whether preoperative serum concentrations of hepatocyte growth factor (HGF) can indicate the general condition of sick children and can predict their postoperative inflammatory response. DESIGN: Non-randomised study. SETTING: University hospital, Japan. SUBJECTS: 41 children who required operation and 41 healthy controls. INTERVENTIONS: Samples of peripheral venous blood were obtained during the operation. MAIN OUTCOME MEASURES: Circulating concentrations of HGF, interleukin-6 (IL-6), and C-reactive protein (CRP); neutrophil counts; and nutritional variables including serum cholinesterase, albumin, and body weight: ideal body weight ratio. RESULTS: The mean serum concentration of HGF in the patients was significantly higher than in the normal controls. Preoperative HGF was related to the preoperative nutritional state, the postoperative IL-6 response, and the development of infective complications. CONCLUSIONS: The serum HGF concentration may be a useful variable for evaluating general condition and predicting perioperative surgical stress in sick children.

Adolescent↗

PubMed2001

Oxidative stress promotes the development of transformation: involvement of a potent mutagenic lipid peroxidation product, acrolein.

The effect of intracellular oxidative stress on the development of cell transformation was studied. Mouse embryo C3H/10T1/2 fibroblasts pre-treated with benzo[a] pyrene, developed transformed foci on exposure to free radical generators, such as 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) and 3-morpholinosydnonimine hydrochloride (SIN-1). These compounds generate peroxyl radicals and peroxynitrite, respectively. Neither AAPH nor SIN-1 alone induced transformation. The level of intracellular antioxidants, such as alpha-tocopherol and glutathione (GSH), decreased with time of exposure to the free radical generators, whereas the addition of exogenous alpha-tocopherol, GSH and ebselen showed a reduction in the frequency of transformation. An early event during exposure to AAPH and SIN-1 was the generation of acrolein, a highly mutagenic lipid peroxidation product, which was suppressed by the addition of alpha-tocopherol. Furthermore, it was confirmed that acrolein induced the transformation of cells which were pre-treated with benzo[a]pyrene but not of the untreated cells. These results suggest that acrolein may act as an important mediator of cell transformation under oxidative stress.

Acrolein↗

PubMed2001

Mechanisms of fluconazole resistance in Candida albicans isolates from Japanese AIDS patients.

Four Candida albicans isolates, TIMM 3163, TIMM 3164, TIMM 3165 and TIMM 3166, with reduced fluconazole susceptibility were obtained from three AIDS patients in Japan, and the mechanisms of their drug resistance were studied. All isolates showed lower levels of intracellular accumulation of fluconazole than ATCC 10231, a susceptible control strain of C. albicans. Increased amounts of CDR1 and CDR2 mRNA encoding putative ATP binding cassette (ABC) transporters were associated with the azole resistance of all TIMM isolates, apart from TIMM 3164. In addition, increased Cdr1p levels were immunodetected in the cell membrane fractions of all the TIMM strains except for TIMM 3164. Gene amplification was not responsible for CDR1 overexpression and there were no significant differences in the mRNA levels of CDR3 or CDR4 (ABC transporters) in the azole-susceptible and -resistant cells. CaMDR1 (a major facilitator superfamily) gene expression was not observed in any of the resistant isolates or the control strain. These results suggest that energy-dependent drug efflux associated with increased expression of CDR1 and CDR2 is involved in the fluconazole resistance mechanisms in two of the four isolates, TIMM 3165 and TIMM 3166. TIMM 3164 demonstrated energy-dependent drug efflux without overexpression of CDR1-4 or CaMDR1, indicating that some other pump may be operating. Despite showing low levels of drug efflux and overexpression of CDR1 and CDR2, efflux in TIMM 3163 was not energy dependent, suggesting that the expressed Cdr1p non-functional Cdr1p and that other resistance mechanisms may operate in this strain.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2001

Synergy of lysozyme and lanoconazole on the morphology of Candida albicans.

Synergism of lysozyme with the imidazole antifungal lanoconazole (LCZ) has been demonstrated in vitro against Candida albicans. To determine the mechanism of the synergistic action, the effects of subinhibitory concentrations of lysozyme (50 microg ml(-1)) and LCZ (1.25 microg ml(-1)), used alone and in combination, on the morphology and ultrastructure of C. albicans cells were studied by fluorescence microscopy using Fungiflora Y, as well as by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the presence of lysozyme, the separation of apparently mature cells from each other was inhibited, and cells in which cell wall-like material had markedly accumulated in the periplasmic space were frequently observed. Such intracellular ultrastructural changes were not seen in LCZ-treated cells, but normal septal wall biogenesis was inhibited with the resultant formation of long chains of interconnecting cells. When the cultures were treated with the combination of lysozyme and LCZ, intracellular accumulation of cell wall-like materials increased in extent, and the peripheral wall structure was severely damaged. These morphological and ultrastructural findings lead us to the following conclusions: (1) lysozyme and LCZ inhibit the process of cell division in different manners; (2) lysozyme appears to affect cell wall formation more directly and drastically by interrupting the normal assembly and integration of cell wall components; and (3) these effects of lysozyme are noticeably enhanced when combined with LCZ.

Antifungal Agents↗

PubMed2001

Curcumin and especially tetrahydrocurcumin ameliorate oxidative stress-induced renal injury in mice.

Protective effects of curcumin (U1), one of the major yellow pigments in turmeric and its derivative, tetrahydrocurcumin (THU1), against ferric nitrilotriacetate (Fe-NTA)-induced oxidative renal damage were studied in male ddY mice. Single Fe-NTA treatment (5 mg Fe/kg body intraperitoneally) transiently causes oxidative stress, as shown by the accumulation of lipid peroxidation products and 8-hydroxy-2'-deoxyguanosine in the kidney. Mice were fed with a diet containing 0.5 g/100 g U1 or THU1 for 4 wk. THU1 significantly inhibited 2-thiobarbituric acid reactive substances and 4-hydroxy-2-nonenal-modified proteins and 8-hydroxy-2'-deoxyguanosine formation in the kidney; U1 inhibited only 4-hydroxy-2-nonenal-modified protein formation. To elucidate the mechanisms of protection by U1 and THU1, the pharmacokinetics and radical-scavenging capacities of U1 and THU1 were investigated by HPLC and electron spin resonance spin trapping with 5,5-dimethyl-1-pyrroline-N-oxide, respectively. Induction of antioxidant enzymes was also investigated. The amounts of THU1 and its conjugates (as sulfates and glucuronides) in the liver and serum were larger in the THU1 group than in the U1 group. The amounts of U1 and its conjugates were small even in the U1 group. These results suggest that THU1 is more easily absorbed from the gastrointestinal tract than U1. Furthermore, THU1 induced antioxidant enzymes, such as glutathione peroxidase, glutathione S-transferase and NADPH: quinone reductase, as well as or better than U1 and scavenged Fe-NTA-induced free radicals in vitro better than U1. These results suggest that U1 is converted to THU1 in vivo and that THU1 is a more promising chemopreventive agent.

Animals↗

PubMed2001

Sex-dependent toxicity of a novel acyl-CoA:cholesterol acyltransferase inhibitor, YIC-C8-434, in relation to sex-specific forms of cytochrome P450 in rats.

YIC-C8-434 is a novel inhibitor of acyl coenzyme A:cholesterol acyltransferase (ACAT). To clarify the toxicity of YIC-C8-434, the compound was given orally to Sprague-Dawley rats for 28 days at 0, 4, 20, 100, or 500 mg/kg/day. The toxicity of the drug differed significantly between male and female rats. In female rats treated at 500 mg/kg, many symptoms including moribund condition, suppression of weight gain and food consumption, abnormal blood chemistry, and decreases in organ weights (thymus, ovaries, and uterus) were observed. In male rats by contrast, no significant toxicity was observed at any dose. After a single administration of YIC-C8-434 at 500 mg/kg, female rats had a higher blood concentration of the compound than male rats. Little elimination of YIC-C8-434 was observed in female rats on analysis of drug-elimination kinetics. Furthermore, the metabolism of YIC-C8-434 was analyzed using rat hepatic microsomal preparations from both sexes. Consistent with the observations in vivo, hepatic microsomes from male rats better metabolized YIC-C8-434 than those from females. In addition, the metabolism of YIC-C8-434 by hepatic microsomes from male rats was blocked by SKF525A, a P450 inhibitor. Inhibition experiments using anti-rat CYP1A1, CYP1A2, CYP2B1, CYP2C11, CYP2E1, CYP3A2, and CYP4A1 antisera indicated that CYP3A2 played the predominant role in the metabolism of YIC-C8-434 in rats. Since there is less CYP3A2 in the liver of female than male rats, the involvement of CYP3A2 in YIC-C8-434 metabolism has implications for the sex-related metabolic activity and toxicity of YIC-C8-434.

Administration, Oral↗

PubMed2001

Lactate is correlated with the indocyanine green elimination rate in liver resection for cirrhotic patients.

UNLABELLED: The role of lactate in liver ischemia-reperfusion injury in cirrhosis has not been clarified. Fifty patients with hepatocellular carcinoma who underwent partial liver resection under Pringle's maneuver were included in this study. We performed the indocyanine green clearance test before the operation and three times during the surgery to calculate its elimination rate. Blood lactate and base excess were measured at the corresponding times. Systolic and diastolic systemic arterial pressure, heart rate, cardiac index, and esophageal temperature were monitored. Aminotransferase levels were recorded the day before the operation, 1 h after the operation, and on the first and third postoperative days. We calculated the increase or decrease in lactate levels during the preischemic, ischemic, and postischemic phases, and examined the correlation between these results and the changes in indocyanine green elimination rate and some clinical factors. The lactate levels increased before reperfusion and began to decrease after reperfusion. The lactate increase and decrease during the ischemic and postischemic phases correlated with the change in indocyanine green elimination rate (P < 0.0001 and P = 0.02 for the respective phases). The lactate increase during the preischemic phase correlated with the duration of the preischemic phase (P < 0.0001). In cirrhotic patients who undergo liver resection with Pringle's maneuver and who do not show postoperative liver failure, the blood lactate profile might be a reliable indicator of liver metabolic capacity during surgery. IMPLICATIONS: In cirrhotic patients who underwent liver resection with Pringle's maneuver, the lactate increase and decrease during the ischemic and postischemic phases correlated with the change in the indocyanine green elimination rate. The blood lactate profile might be a reliable indicator of liver metabolic capacity during surgery.

Adult↗

PubMed2001

Signaling pathway and chronotropic action of parathyroid hormone in isolated perfused rat heart.

Parathyroid hormone (PTH) activates both adenylyl cyclase and phospholipase C via the PTH-1 receptor. We previously reported that PTH increased heart rate and that this effect was mediated via the pacemaker current (I f ). However, it has been reported that PTH exerts its chronotropic effect via an interaction with adrenergic receptors or via L-type calcium channels. Thus, the objective of the study was to elucidate the exact mechanism of the chronotropic effect of PTH. We tested whether its chronotropic effects could be abolished by inhibitors of the following systems in isolated perfused rat hearts: alpha-adrenergic (prazosin); beta-adrenergic (propranolol); angiotensin II (CV11974); endothelin-1 (TAK044); calcium channel (verapamil); adenylyl cyclase (miconazole); phospholipase C (U73122) or I f (CsCl). In addition, we measured the cyclic adenosine monophosphate level of the heart after PTH administration. Whereas prazosin, propranolol, CV11974, TAK044, verapamil, and U73122 did not inhibit the chronotropic effect of PTH, CsCl or miconazole suppressed it significantly. PTH increased the cyclic adenosine monophosphate level of the atrium but not the left ventricle. These results indicate that the chronotropic actions of PTH are mediated via selective activation of adenylyl cyclase to increase the I f current.

Adenylyl Cyclases↗

PubMed2001

Involvement of lipid peroxidation in spontaneous pancreatitis in WBN/Kob rats.

To cast light on the mechanisms underlying development of spontaneous pancreatitis lesions, tissues from WBN/Kob rats at various ages were histopathologically and immunohistochemically investigated with special reference to the existence of the lipid peroxidation products 4-hydroxy-2-nonenal (HNE), 4-hydroxy-2-hexenal (HHE), and malondialdehyde (MDA). Male 4-20-week-old WBN/Kob rats were killed to allow sampling of pancreatic tissues, which were fixed in cold acetone and 10% neutral-buffered formalin. and then processed for routine histopathology as well as immunohistochemistry for proteins modified by HNE, HHE, and MDA. Although no remarkable histologic changes were noted in younger animals, edema, hemorrhage, inflammatory cell infiltration, fibrosis, vacuolation of acinar cells, and ductular proliferation were observed in exocrine pancreatic tissue from animals at 10-15 weeks of age. In animals aged 20 weeks, the lesions had progressed remarkably and deposits of hemosiderin were apparent with fibrosis. Immunohistochemical examination for lipid peroxidation product-modified proteins showed HNE and MDA to be negative in all pancreatic tissues, but HHE was positive in the areas involving atrophy of acinar cells and fibrosis in the islets. The results of the present study thus provide support for the conclusion that lipid peroxidation during spontaneous pancreatitis in WBN/Kob rats may possibly be involved in the development of diabetes in this model.

Aging↗