Biomedical subjects

K Uchida

Publications and source records attributed to K Uchida.

At least 253 records · Page 14Linked to original sources

PubMed2000

Cellular response to bioactive lipid peroxidation products.

Reactive aldehydes, such as 4-hydroxy-2-nonenal, have been implicated as inducers in generating intracellular reactive oxygen species and activation of stress signaling pathways, that integrate with other signaling pathways to control cellular responses to the extracellular stimuli. Here, I briefly summarize a novel signaling pathway in cellular response, in which aldehyde-stimulated detoxification response is mediated by cyclooxygenase metabolites. These findings argue that lipid mediators could induce a cellular process that represents a cellular defense program against toxic compounds.

Aldehydes↗

PubMed2000

Serum 4-hydroxy-2-nonenal-modified albumin is elevated in patients with type 2 diabetes mellitus.

4-Hydroxy-2-nonenal (HNE) is one of the major lipid peroxidation products with cytotoxic and mutagenic activity. It further reacts with protein residues such as histidine to generate stable Michael adducts. To evaluate the status of oxidative stress in the serum of type 2 diabetes mellitus, we constructed a sandwich enzyme-linked immunosorbent assay to measure serum HNE-modified albumin by the use of a specific monoclonal antibody (HNEJ-2) against HNE-histidine adducts as well as an antibody against human serum albumin. Serum of type 2 diabetes outpatients revealed significantly higher levels of HNE-modified albumin (736.1 +/- 34.2 pmol/ml, n = 54) than the matched nondiabetics (611.4 +/- 39.1 pmol/ml, n = 30; means +/- SEM; p = 0.018). However, no significant correlation was observed in diabetic outpatients between the levels of HNE-modified albumin and clinical parameters such as fasted blood glucose, HbA1c, diabetes duration, or complications. Our data demonstrated the increased formation of serum HNE-modified albumin in type 2 diabetic outpatients in the milieu between liver and vascular lumina, indicating the presence of oxidative stress.

Aged↗

PubMed2000

Lactoferrin given in food facilitates dermatophytosis cure in guinea pig models.

Dermatophytosis is the most common skin infection caused by dermatophytic fungi, such as Trichophyton spp. We studied the in vitro and in vivo antifungal effects of lactoferrin against Trichophyton. Human and bovine lactoferrin, and a bovine lactoferrin-derived peptide, lactoferricin B, showed in vitro antifungal activity that was dependent on the test strain and medium used. In guinea pigs infected on the back with Trichophyton mentagrophytes (i.e. those with tinea corporis), consecutive daily po administration of bovine lactoferrin did not prevent development of symptoms during the early phase of infection, but facilitated clinical improvement of skin lesions after the peak of the symptoms. The fungal burden in lesions was less in guinea pigs that had been given lactoferrin than in untreated controls 21 days after infection. In guinea pigs infected on the foot with T. mentagrophytes (i.e. those with tinea pedis), the fungal burden of the skin on the heel portion of the infected foot 35 days after infection was lower in animals fed lactoferrin than in controls. These results suggest the potential usefulness of lactoferrin as a food component for promoting dermatophytosis cure.

Administration, Oral↗

PubMed2000

Screening for prostate cancer using prostate-specific antigen alone as a first-line checkup parameter: results of the health checkup system.

BACKGROUND: The incidence of prostate cancer in Japan is not very high but it is the most increasing malignant tumor form. To decrease the mortality from cancer, detection of early cancer and early treatment are most effective. As a primary screening for prostate cancer, measurement of serum prostate-specific antigen(PSA) added to the health checkup system has not been assessed. METHODS: Among males who received a health checkup during a 30-month period, serum PSA levels were measured in males who desired prostate cancer screening. The cut-off value for PSA was 4.0 ng/ml. Males with serum PSA levels exceeding this value were referred for further screening by digital rectal examination (DRE) and transrectal ultrasonography (TRUS). In secondary screening, in all males with PSA levels of 10.0 ng/ml or more and in males in whom PSA levels were within the gray zone (4.0-10.0 ng/ml) and either DRE or TRUS showed abnormal findings, systematic prostate sextant needle biopsy was performed. RESULTS: Of 24528 males who received a health checkup, 1125 (4.6%) underwent prostate cancer screening. In 60 (5.3%) of these males, PSA levels exceeded the cut-off value. In 34 of 50 males who received further screening, prostate biopsy was performed. Seventeen males were diagnosed as having prostate cancer. Detection rates of prostate cancer were 1.53% (17/1125) in males overall and 2.1% (17/819) in males > or =50 years old. In 16 of 17 males, clinically localized cancer was suggested. In 12 of these patients, radical prostatectomy was performed. No lymph node metastasis was detected in any patient. CONCLUSIONS: These results suggest that prostate cancer screening using PSA as a primary screening parameter during general health checkups is very useful for efficiently detecting early-stage prostate cancer.

Aged↗

PubMed2000

Cloning and characterization of a complementary deoxyribonucleic acid encoding haploid-specific alanine-rich acidic protein located on chromosome-X.

We have isolated a cDNA clone encoding a germ cell-specific protein from an expression cDNA library prepared from the mouse testis using testis-specific polyclonal antibodies. Northern blot analysis showed a transcript of 1.1 kilobases exclusively expressed in haploid germ cells of the testis. Sequence analysis of the cDNA revealed one long open reading frame consisting of 238 deduced amino acids, rich in basic amino acids in the N-terminal one-third that also contained the nuclear localization signal, and rich in acidic amino acids, including two type of acidic alanine-rich repeats, in the rest of the deduced protein. The protein having a molecular weight of approximately 55 kDa and an isoelectric point of pH 4.3-4.7 was also exclusively detected in the testis by Western blot analysis. As the cDNA was located on chromosome-X, Halap-X (haploid-specific alanine-rich acidic protein located on chromosome-X) was proposed for the name of the protein encoded by the cDNA. Immunohistochemical observation revealed that the Halap-X protein was predominantly present in the nucleoplasm of round spermatids but gradually decreased as spermatids matured, followed by the subsequent appearance in the cytoplasm of elongating spermatids. Thus, the Halap-X protein was transferred from the nuclei to the cytoplasm during the spermatid maturation when the chromatin condensation and transformation of the nuclei occurred. The Halap-X may facilitate specific association of nuclear DNA with some basic chromosomal proteins and play important roles in the process of chromatin condensation.

Amino Acid Sequence↗

PubMed2000

Elementary processes of photoperception by phytochrome A for high-irradiance response of hypocotyl elongation in Arabidopsis.

Elementary processes of photoperception by phytochrome A (PhyA) for the high-irradiance response (HIR) of hypocotyl elongation in Arabidopsis were examined using a newly designed irradiator with LED. The effect of continuous irradiation with far-red (FR) light could be replaced by intermittent irradiation with FR light pulses if given at intervals of 3 min or less for 24 h. In this response, the Bunsen-Roscoe law of reciprocity held in each FR light pulse. Therefore, we determined the action spectrum for the response by intermittent irradiation using phyB and phyAphyB double mutants. The resultant action spectrum correlated well with the absorption spectrum of PhyA in far-red-absorbing phytochrome (Pfr). Intermittent irradiation with 550 to 667 nm of light alone had no significant effect on the response. In contrast, intermittent irradiation with red light immediately after each FR light pulse completely reversed the effect of FR light in each cycle. The results indicate that neither red-absorbing phytochrome synthesized in darkness nor photoconverted Pfr are physiologically active, and that a short-lived signal is induced during photoconversion from Pfr to red-absorbing phytochrome. The mode of photoperception by PhyA for HIR is essentially different from that by PhyA for very-low-fluence responses and phytochrome B for low-fluence responses.

Arabidopsis↗

PubMed2000

Glutathione and a UV light-induced glutathione S-transferase are involved in signaling to chalcone synthase in cell cultures.

UV irradiation stimulates expression of the gene encoding the key enzyme chalcone synthase (CHS), which leads to the generation of protective flavonoids in parsley cell cultures. CHS transcripts increase after 3 to 4 hr, and early genes are involved in the signal transduction to the CHS promoter. By using the fluorescent differential display technique in a large-scale screening, several early UV light-induced genes were isolated. Of these, a novel glutathione S-transferase (PcGST1) is induced within 2 hr and precedes CHS expression. Overexpression of PcGST1 in transformed cell lines containing a CHS promoter/luciferase reporter (CHS-LUC) affected the onset of LUC transcription. Supplementing these cell lines with glutathione immediately stimulated CHS-LUC expression within 2 hr in dark-incubated cells and resulted in a biphasic induction profile in UV-irradiated cells. Our data indicate the involvement of glutathione and PcGST1 in early events of a UV light-dependent signal transduction pathway to CHS. In this context, the oxidative status of a cell acts as a central regulating element.

Acyltransferases↗

PubMed2000

Successful interferon therapy reverses enhanced hepatic iron accumulation and lipid peroxidation in chronic hepatitis C.

OBJECTIVES: Hepatic iron deposition has been reported in chronic hepatitis C (CH-C), and iron-induced lipid peroxidation may be involved in the pathogenesis of CH-C. The aims of the present study were: 1) to determine whether patients with CH-C have evidence of enhanced hepatic lipid peroxidation and to evaluate its relation to iron status, compared with that in patients with chronic hepatitis B (CH-B); and 2) to assess the effect of interferon (IFN) therapy on hepatic iron and lipid peroxidation. METHODS: In the liver biopsies of 40 patients with CH-C and 26 patients with CH-B, immunohistochemical detection of 4-hydroxy-2-nonenal (HNE)-protein adducts for evaluation of lipid peroxidation was performed, and hepatic iron status was biochemically and histologically assessed. In 16 CH-C patients with normal serum transaminases and undetectable serum HCV-RNA >6 months after the end of IFN treatment (responders) and in 11 nonresponders, hepatic HNE-protein adducts and siderosis were evaluated in pre- and posttreatment liver biopsies. RESULTS: Hepatocytic HNE-protein adducts and iron deposits were more abundant in the patients with CH-C than in those with CH-B. No correlation was found between the levels of hepatocytic HNE-protein adducts and hepatic iron status in either of the two groups. In the responders to IFN treatment for CH-C, hepatocytic HNE-protein adducts disappeared or attenuated with improvement of hepatic siderosis after the treatment, whereas IFN treatment did not improve hepatocytic expression of HNE-protein adducts and hepatic siderosis in the nonresponders. CONCLUSIONS: Patients with CH-C have evidence of enhanced hepatic iron accumulation and lipid peroxidation compared to those with CH-B. In CH-C, hepatic siderosis and lipid peroxidation are improved with successful IFN treatment. These results suggest that hepatic lipid peroxidation and iron may potentially play contributory roles in the pathogenesis of CH-C.

Adult↗

PubMed2000

Clinical analysis of autoimmune-related pancreatitis.

OBJECTIVE: Several investigators have reported on autoimmune-related pancreatitis, but the clinical findings and pathophysiology still remain unclear. To clarify it, we analyzed eight patients with autoimmune pancreatitis. METHODS: We evaluated clinical findings in eight patients (four men and four women) with autoimmune-related pancreatitis. Patients were aged 45-73 yr (mean, 57.5 yr). We examined blood chemistry and immunological studies, including autoantibodies against lactoferrin or carbonic anhydrase II, and compared ERCP images with clinical findings. In two patients, we studied the subset of lymphocytes infiltrating in the pancreas by immunohistochemistry and flow cytometry. RESULTS: Four of eight patients had jaundice, two had renal dysfunction, two had abdominal pain, and two had back pain. Three patients were complicated with other autoimmune diseases. Three patients showed abnormal pancreatic exocrine function by an N-benzoyl-L-tyrosyl-para-aminobenzoic acid excretion test. Antinuclear antibody was detected in four of eight patients, antilactoferrin antibody in three of six, anticarbonic anhydrase II antibody in two of six, antismooth muscle antibody in two of seven, and rheumatoid factor in one of eight. All eight patients showed segmental stenosis of the main pancreatic duct by ERCP. Four patients showed stenosis of the common bile duct as well as the pancreatic duct. Microscopic findings showed infiltration of CD4-positive lymphocytes around the pancreatic duct, and HLA-DR was expressed on both CD4-positive cells and pancreatic duct cells. In two patients, stenosis of the pancreatic duct improved by prednisolone. CONCLUSIONS: Autoimmune mechanism may be involved in some patients with idiopathic pancreatitis associated with hypergammaglobulinemia.

Aged↗

PubMed2000

Enhanced hepatic lipid peroxidation in patients with primary biliary cirrhosis.

OBJECTIVE: The mechanisms responsible for hepatic injury have not been fully clarified in primary biliary cirrhosis (PBC). It has recently been suggested that hepatic lipid peroxidation may be involved in the pathogenesis of PBC. The aims of the current study were to determine whether patients with PBC have evidence of enhanced hepatic lipid peroxidation and to evaluate its relationship to clinicopathological features. METHODS: Immunohistochemical detection of 4-hydroxynonenal (HNE) protein adducts was performed in the liver biopsies of 20 patients with PBC. Histological stages of PBC were evaluated. Orcein or Victoria blue staining was performed for detection of copper-associated proteins. The size of bile ducts was defined as the smallest diameter between the subepithelial basement membranes. RESULTS: All 20 patients had immunodetectable HNE protein adducts in the cytoplasm of damaged, but also intact, biliary cells. The mean diameter of bile ducts with HNE protein adducts was smaller than those without the adducts (61.0 +/- 1.9 vs 122.5 +/- 24.4 microm, respectively, p < 0.01). Out of 20 patients, 6 (30%) also had immunodetectable HNE protein adducts in hepatocytes preferentially located around the portal tracts. Most of the patients with hepatocytic HNE protein adducts had copper-associated protein granules in hepatocytes around the portal tracts and were classified as histological stage 3, whereas all of the patients without the adducts lacked copper-associated protein granules and were classified as histological stage 1 or 2. The patients with hepatocytic HNE protein adducts had higher levels of serum total bilirubin than did those without the adducts (2.9 +/- 0.9 vs 0.7 +/- 0.1 mg/dl, respectively, p < 0.01). CONCLUSIONS: Hepatic lipid peroxidation can occur in PBC and may be an early event in bile duct destruction. At advanced stages of PBC, hepatocellular lipid peroxidation may play a role in hepatocyte injury during cholestasis.

Aldehydes↗

PubMed2000

Therapeutic efficacy of human macrophage colony-stimulating factor, used alone and in combination with antifungal agents, in mice with systemic Candida albicans infection.

We examined the in vivo activity of human macrophage colony-stimulating factor (hM-CSF) against lethal Candida albicans infection in mice. In C. albicans-infected mice which had been immunosuppressed with cyclophosphamide, treatment with hM-CSF at a daily dose of 8 x 10(5) units/kg of body weight or greater slightly but significantly prolonged survival. Furthermore, the therapeutic efficacy of amphotericin B (AMPH-B) in infected mice was enhanced by its combined use with hM-CSF, while that of fluconazole (FLCZ) was not. The activities of peritoneal macrophages and neutrophils from mice administered hM-CSF plus AMPH-B in combination for inhibition of hyphal growth of C. albicans cells and intracellular phagocytosis and killing of the cells were greater than those of comparable phagocytic cells from control mice to which hM-CSF plus AMPH-B was not administered. These results suggest that intravenous administration of hM-CSF augments the efficacy of AMPH-B by enhancing the antifungal activities of macrophages and neutrophils. Therefore, it is expected that therapy with the combination AMPH-B and hM-CSF could improve the efficacy of AMPH-B and reduce the therapeutic dose of the antifungal drug that is required.

Amphotericin B↗

PubMed2000

Colonization of the stratified squamous epithelium of the nonsecreting area of horse stomach by lactobacilli.

Selective adhesion to only certain epithelia is particularly common among the bacterial members of the indigenous microflora of mammals. We have found that the stratified squamous epithelium of the nonsecreting area of horse stomach is colonized by gram-positive rods. The microscopic features of a dense layer of these bacteria on the epithelium were found to be similar to those reported in mice, rats, and swine. Adhering microorganisms were isolated and identified as Lactobacillus salivarius, L. crispatus, L. reuteri, and L. agilis by DNA-DNA hybridization and 16S rRNA gene sequencing techniques. These lactobacilli associated with the horse, except for L. reuteri, were found to adhere to horse epithelial cells in vitro but not to those of rats. A symbiotic relationship of these lactobacilli with the horse is suggested.

Animals↗

PubMed2000

Involvement of tyrosine kinase in citrate-stimulated aldosterone production in bovine glomerulosa cells.

The present study was designed to assess whether citrate stimulates aldosterone production by isolated bovine adrenal glomerulosa cells in vitro. When the cells were incubated with graded concentrations of citrate up to 4.0 mM, basal aldosterone production was significantly elevated, with a gradual reduction of extracellular ionized calcium concentration. Without citrate, however, adding increasing amounts of calcium chloride to a calcium-free medium did not reproduce the citrate's effect on basal aldosterone production. Genistein, an inhibitor of tyrosine kinases, inhibited the citrate (4 mM)-induced aldosterone production in a dose-dependent manner, with 89.8% of inhibition at a concentration of 10 microM. When the cells were exposed to citrate (4 mM) for 5, 10, and 30 min, tyrosine in Mr 105,000 endogenous protein was dominantly phosphorylated. This study demonstrates for the first time that citrate stimulates aldosterone production in bovine adrenal glomerulosa cells in vitro and also suggests a crucial involvement of protein tyrosine kinase in the steroidogenic action of citrate in the cells.

Aldosterone↗

PubMed2000

Effects of Ba(2+) on norepinephrine-induced contraction of rat thoracic aorta in vitro.

The aim of this study was to examine the effect of exogenously applied BaCl(2) on the norepinephrine-induced contraction of the rat thoracic aorta. Exogenously applied BaCl(2) (0.3-1 mmol/l) slightly elevated the norepinephrine-induced sustained contraction of the rat thoracic aorta in the absence of nicardipine (1 micromol/l). In the aortic preparation pretreated with nicardipine (1 micromol/l), exogenous BaCl(2) (0.1-3 mmol/l) did not elevate the norepinephrine-induced sustained contraction, but the high concentration of BaCl(2) (10 mmol/l) slightly inhibited the norepinephrine-induced tone. In a Ca(2+)-free Krebs bi- carbonate solution (KBS) containing norepinephrine (1 micromol/l) or a Ca(2+)-free K(+)-rich (60 mmol/l) KBS, exogenously applied BaCl(2) (1-30 mmol/l) caused a sustained contraction of the rat thoracic aorta, and this sustained contraction was completely inhibited by nicardipine (1 micromol/l). Exogenous CaCl(2) (0.1-3 mmol/l) also caused a sustained contraction of the aortic preparation in a Ca(2+)- free KBS containing norephinephrine (1 micromol/l), but such a sustained contraction was partly inhibited by nicardipine (3 micromol/l). These results indicate that Ba(2+) elevates the norepinephrine-induced tone of the rat isolated thoracic aorta by permeating voltage-dependent Ca(2+) channels in the absence of nicardipine, but that Ba(2+) has a minor modification on the norepinephrine-induced sustained contraction of the nicardipine-pretreated preparation.

Animals↗

PubMed2000