Biomedical subjects

H Eguchi

Publications and source records attributed to H Eguchi.

At least 127 records · Page 7Linked to original sources

PubMed1995

Genetic polymorphisms of drug-metabolizing enzymes and lung cancer susceptibility.

A close association of smoking-associated lung cancer incidence with the Msp 1 and 1le-Val polymorphisms of CYP1A1 gene was found in a Japanese population in terms of genotype frequency comparison and cigarette dose response. A synergistic increase in susceptibility to lung cancer was observed when the susceptible genotypes of CYP1A1 were combined with a deficient GSTM1 genotype. Individual difference in expression levels of Ahr and Arnt mRNAs was observed, and the expression levels of CYP1A1 appeared to associate with those of transcriptional factors. The Ahr protein has two different structures, ascribed to one amino acid replacement at codon 554 of Arg by Lys. However, this germ line polymorphism did not show a significant association with AHH inducibility nor lung cancer incidence. The p53 gene alterations in lung cancer tissues were more frequently observed among the patients with a susceptible allele of CYP1A1 gene.

Chromosome Aberrations↗

PubMed1995

In vitro comparative study of the antitumor effects of human interferon-alpha, beta and gamma on the growth and invasive potential of human melanoma cells.

We have studied the effects of interferon (IFN)-alpha, beta, and gamma in vitro on the growth and invasive potential of human melanoma SK-MEL-118 cells. The antiproliferative effects of IFNs were assessed by a quantitative regrowth assay in which cells were treated with IFNs at concentrations of 10(2), 10(3) or 10(4) IU/ml for 3 days (until day 4) and then further incubated without IFNs for 7 days (until day 11). The growth inhibitory effect of each IFN on melanoma cells was dose- and time-dependent. Among these three types of IFNs, however, IFN-beta exerted the strongest inhibitory effect on cell growth. To assess the anti-invasive effect of each IFN on melanoma cells, we employed an in vitro assay system using matrigel-coated Transwell chambers. When cells were treated with 10(2), 10(3), or 10(4) IU/ml of the three types of IFNs for 24 hours, the amount of tritiated thymidine incorporated into melanoma cells were treated for 24 hours with 10(4) IU/ml of IFN-beta or gamma prior to the assay, the number of cells that invaded the filter decreased by 40%; this decrease was only 10% with the same amount of IFN-alpha. Simultaneous addition of IFNs during the invasion assay was not effective in any combination. Only when the cells were pretreated with IFNs, antiinvasive effects against melanoma cells were exerted. IFN-alpha was less inhibitory than IFN-beta or gamma on proliferation and not at all inhibitory on invasion. Considering both the antiproliferative and antiinvasive effects of IFNs, our results suggest that IFN-beta has the strongest antitumoral effect on human melanoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Division↗

PubMed1995

An Rsa I polymorphism in the CYP2E1 gene does not affect lung cancer risk in a Japanese population.

CYP2E1 catalyzes the metabolic activation of tobacco-specific N-nitrosamines, including 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone. An Rsa I polymorphism, which is located in the 5'-flanking region of the CYP2E1 gene, has been found to affect the transcriptional regulation of the gene, resulting in different expression levels of the mRNA among individuals. In order to investigate an association between the Rsa I polymorphism and lung cancer susceptibility, the genotype distribution among 316 lung cancer patients was compared with that in 503 healthy controls. No statistically significant association was found between the Rsa I polymorphism and an increased risk of lung cancer, even though histological types of lung cancer, cigarette smoking and alcohol consumption were taken into account.

Cytochrome P-450 CYP2E1↗

PubMed1995

Clonal and non-clonal karyotypically abnormal cells in haemophagocytic lymphohistiocytosis.

We studied chromosomes in bone marrow (BM) or peripheral blood cells of nine patients with haemophagocytic lymphohistiocytosis (HLH); three of them had a family history of HLH and four others underwent concurrent Epstein-Barr virus (EBV) infection. In addition to a large population of normal mitotic cells, karyotypically abnormal clonal cells were found in two patients, abnormal clonal cells and a nonclonal (single) abnormal cell in one, and nonclonal abnormal cells in three. All the six patients with chromosome abnormalities died of progressive disease; one of them also had EBV infection and EBV-associated clonal proliferation. Two of three patients with EBV infection and only normal mitotic cells in BM completely recovered from the disease. Although HLH did not show histological and/or haematological evidence of a neoplastic disease, clonal chromosome abnormalities and the fatal clinical outcome found in some of the patients suggest that the disease may be heterogenous and include malignancy. HLH patients with karyotypically abnormal clonal cells in BM should warrant more intensive chemotherapy than that presently being applied to them and should be considered as candidates for BM transplantation.

Adolescent↗

PubMed1995

Role of endotoxin in the hepatic microvascular inflammatory response to ethanol.

Kupffer cells (KC) and gut-derived bacterial endotoxin have been implicated in the aetiology of alcoholic liver disease. Using in vivo microscopic methods, we have shown that ethanol ingestion in mice causes a dose dependent increase in leucocyte adhesion and endothelial cell swelling in hepatic sinusoids. Activation of KC is elicited at low doses while depression occurs at high doses and with chronic exposure. The responses are exacerbated in the presence of endotoxaemia or sepsis and are not seen in endotoxin-resistant animals, implicating a role for endotoxin in the ethanol-induced inflammatory response. In addition, the responses are abolished with anti-TNF alpha suggesting that TNF alpha is a primary mediator of these events. Nitric oxide (NO) initially appears to play an important role in these events by stabilizing the TNF alpha-mediated hepatic microvascular inflammatory response to acute ethanol ingestion, thereby helping to protect the liver from ischaemia and leucocyte induced oxidative injury. Finally, an ongoing clinical study has confirmed a mild systemic endotoxaemia in patients hospitalized for alcoholic liver disease. All of these results support important roles for endotoxin, cytokines, nitric oxide and sinusoidal lining cells in the pathophysiology of liver injury resulting from ethanol alone or in combination with infection.

Animals↗

PubMed1995

Insulin-like growth factor I resistance in peripheral tissue but not in liver in streptozotocin-induced diabetic rats.

The metabolic effect of recombinant human insulin-like growth factor I (IGF-I) was investigated by the glucose clamp technique in normal rats and streptozotocin-induced diabetic rats, a model of insulin-dependent diabetes mellitus (IDDM), and compared with that of insulin. Glucose uptake by peripheral tissues was stimulated by intravenous administration of IGF-I at rates of from 0.369 to 3.690 nmol/kg/min in a dose dependent manner, with a potency of 1/52 that of insulin estimated on the basis of the ED50 molar ratio in normal rats. In streptozotocin-induced diabetic rats, the maximum effects of IGF-I and insulin were reduced to 72% and 70% of those in normal rats, respectively, indicating the presence of both IGF-I and insulin resistance. Hepatic glucose output in normal rats was suppressed by IGF-I in a dose dependent manner with a weaker potency of 1/99 that of insulin assessed on the basis of the ED50 values. In streptozotocin-induced diabetic rats, a dose-response curve of the suppressive effect of insulin on hepatic glucose output shifted to the right, indicating the presence of hepatic insulin resistance, but a leftward shifting of the suppressive effect of IGF-I on hepatic glucose output was observed. We concluded that the IGF-I effect on peripheral tissue was decreased but that on the liver was rather increased in streptozotocin-induced diabetic rats, in contrast to the resistance of both peripheral tissues and liver to insulin.

Animals↗

PubMed1995

[Treatment results of acute nonlymphocytic leukemia in childhood--Kyushu Yamaguchi Children's Cancer Study Group].

Seventy-three children with acute nonlymphocytic leukemia (ANLL) have been treated with ANLL-85 and ANLL-88 protocol at Kyushu-Yamaguchi Children's Cancer Study Group between June, 1985 and February, 1993. Ten boys and 10 girls (0y4m-16ylm) were treated with the ANLL-85 protocol. The complete remission (CR) rate was 75% and the 5-year event free survival (EFS) was 20 +/- 9%. It was terminated because of frequent early relapse (within 6 months after CR). Thirty-four boys and 19 girls (0y3m-17ylm) were treated with the ANLL-88 protocol. The CR rate was 85% and the 5-year EFS was 32 +/- 7%. Early relapse rate with ANLL-88 was lower than that of ANLL-85, however 9 cases relapsed after terminating therapy. Although bone marrow transplantation (BMT) from related donors during the first CR was effective in ANLL-88, EFS was not improved. Recognition of risk factors and appropriate chemotherapy regimens with or without the support of stem cell transplantation may be necessary to cure children with ANLL.

Adolescent↗

PubMed1994

Antagonistic activities of N-3389, a newly synthesized diazabicyclo derivative, at 5-HT3 and 5-HT4 receptors.

The antagonistic activities of compound N-3389 (endo-3,9-dimethyl-3,9- diazabicyclo[3,3,1]non-7-yl 1H-indazole-3-carboxamide dihydrochloride) at 5-HT3 and 5-HT4 receptors were examined using in vitro and in vivo assays. N-3389 showed potent 5-HT3 receptor antagonistic activities in a radioligand binding assay (pKi = 8.77), against 2-methyl-5-HT (2-Me-5-HT)-induced bradycardia in rats (ED50 = 0.73 micrograms/kg i.v., 38 micrograms/kg p.o.) and against 2-Me-5-HT-induced contraction in longitudinal muscle myenteric plexus preparations of guinea-pig ileum (IC50 = 3.2 x 10(-8) M). As a preliminary to investigating the effect of N-3389 on 5-HT4 receptors, we examined the contraction induced by 5-HT in guinea-pig ileum preparations. We confirmed that 5-HT (10(-8)-10(-5) M) induced biphasic contractions in the preparations. Furthermore, 5-HT3 receptor antagonism inhibited the late phase of the contraction induced by high concentrations of 5-HT (3 x 10(-6)-10(-5) M), whereas 5-HT4 receptor antagonism inhibited the early phase of the contraction induced by low concentrations of 5-HT (10(-8)-10(-6) M). N-3389 (10(-7)-10(-5) M) inhibited both phases of contraction induced by 5-HT. In addition, N-3389 (3 x 10(-7)-3 x 10(-6) M) was found to inhibit the increase of electrically stimulated twitch responses induced by 5-HT (10(-8) M) longitudinal muscle myenteric plexus preparation of the guinea-pig ileum. These results suggest that N-3389 acts as a 5-HT3 and 5-HT4 receptor antagonist.

Animals↗

PubMed1994

Molecular cloning of the human AH receptor gene promoter.

A lambda phage clone containing a promoter region of the human Ah receptor gene was isolated. This clone spanned 13.8 kb and contained the 1st exon, the sequence of which completely matched the reported Ah receptor cDNA. Using RNase protection assay and primer extension analysis, the transcription initiation sites were determined to be 643 and 615 bp upstream of the translational initiation codon ATG. This promoter did not contain a TATA box, while multiple GC boxes were present close to the determined transcription initiation sites. Comparison of the 5' flank sequence of the human Ah receptor with its murine equivalent showed several well conserved regions, containing binding sites for known transcription factors, such as Sp1. The promoter activity was confirmed by transient transfection of chimeric constructs of the Ah receptor gene and reporter gene luciferase into hepatoma HepG2 cells.

Animals↗

PubMed1994

Transactivation of the rat CYP2C13 gene promoter involves HNF-1, HNF-3, and members of the orphan receptor subfamily.

The rat CYP2C13 gene (2C13) encodes one of the constitutive male forms of cytochrome P-450 that are involved in steroid metabolism. In addition to being developmentally regulated, the expression of 2C13 is restricted to the liver and suppressed by the female pattern of growth hormone (GH) secretion at the transcriptional initiation level. In this study, we show that the liver-specific expression, but not the regulation by GH, can be reconstituted with 117 bp to 2 kb of 2C13 5' flank. Transactivation of the 2C13 promoter requires both HNF-1 and HNF-3 and is influenced by members of the orphan receptor subfamily of transcription factors. Although HNF-4, ARP-1, EAR-2, and COUP-TF bind to the 2C13 promoter in vitro, overexpression of EAR-2 and COUP-TF, but not of HNF-4 or ARP-1, results in the potentiation of the HNF-3- and HNF-1-supported activity in non-liver cells.

Animals↗

PubMed1994

Identification of matrix metalloproteinase 9 in rabbit osteoclasts.

Osteoclasts are multinucleate giant cells that play key roles in bone resorption. To identify genes predominantly expressed in osteoclasts, we screened a cDNA library of osteoclasts with cDNA probes of osteoclasts and alveolar macrophages. Clones specifically hybridizing to the osteoclast probe were isolated and sequenced. The nucleotide sequence of one such clone, F17, was found to share significant similarity with the sequences of human and mouse matrix metalloproteinase 9 (MMP-9) cDNA. By isolation and sequencing of the full-length cDNA, F17 was revealed to encode the rabbit counterpart of MMP-9. By Northern blotting, messenger RNA for MMP-9 was found to be highly and predominantly expressed in isolated osteoclasts when compared with its level in alveolar macrophages and other tissues. By gelatin zymography, gelatinase activity was detected in conditioned medium of isolated osteoclasts, suggesting that MMP-9 is secreted by isolated osteoclasts. Expression of MMP-9 was also observed in in vivo osteoclasts in metacarpal bones of newborn rabbits by in situ hybridization. These facts suggest that MMP-9 is one of the major proteases produced by osteoclasts and possibly plays a role in osteoclastic bone resorption.

Amino Acid Sequence↗

PubMed1994

Evaluation of melanin-related metabolites as markers of melanoma progression.

BACKGROUND: Urinary excretion of 5-S-cysteinyldopa (5-S-CD) has been used as a biochemical marker of melanoma progression. Melanomas produce not only 5-S-CD but also 5,6-dihydroxyindole-2-carboxylic acid (5,6DHI2C) as major intermediates in melanin formation. 5,6DHI2C is then metabolized to the two O-methyl derivatives, 5H6MI2C and 6H5MI2C. The aim of this study was to determine which marker in serum and urine most sensitively reflected the progression of melanoma. METHODS: Serum and 24-hour urine samples were collected and assayed serially by high-performance liquid chromatography every 1 to 4 months in 28 patients with primary or recurrent melanomas, for up to 48 months. RESULTS: Serum concentration and urinary excretion of 5-S-CD and 6H5MI2C in patients with melanoma without metastases were close to those obtained from normal subjects. Metastases developed in 9 of the 28 patients. In seven of these nine patients, serum or urinary 5-S-CD values were elevated before or at the time of clinical detection of visceral metastases. However, serum 5-S-CD was elevated significantly earlier and reflected melanoma progression better than the physical examination and/or laboratory tests, such as scintigraphy and echography. Serum 6H5MI2C values exceeded the normal range shortly before death in three patients, and urinary 6H5MI2C did not increase at any stage in most patients, therefore these metabolites did not reflect progression of disease. CONCLUSIONS: Among the four markers, serum 5-S-CD appears to be the best biochemical marker for the detection of progression of melanotic melanoma, a value of more than 10 nmol/l suggesting the presence of metastasis.

Adult↗

PubMed1994

Binding and metabolism of platelet-activating factor (PAF) by isolated rat type II pneumonocytes.

The specific binding of platelet-activating factor (PAF) to isolated type II pneumonocytes from rat lung has been investigated employing an intact cell preparation. The dissociation constant (Kd) for the autacoid has been determined to be 0.46 x 10(-9) M and approximately 3000 receptor sites per cell are present. In studies conducted on the metabolism of PAF in these cells, it was demonstrated that PAF is rapidly converted into 1-alkyl-2-acylglycerophosphocholine (alkyl-acyl GPC). After longer time intervals there was a substantial conversion of alkyl-acyl GPC into alkyl-acylglycerophosphoethanolamine (alkyl-acyl GPE). Both the alkyl-acyl GPC and alkyl-acyl GPE fractions were devoid of plasmalogens. The alkyl-acyl GPC fraction was further characterized and a distinct double peak could be visualized following thin-layer chromatography and the same lyso-compound was produced from both peaks following mild alkaline hydrolysis. By using appropriate standards it was concluded that the dual alkyl-acyl GPC peaks represent differences in the fatty acid present in the sn-2 position. One peak corresponds to the presence of saturated fatty acid in the sn-2 position and is probably due to the characteristic high capacity of the type II cells to produce disaturated glycerophospholipids.

Animals↗

PubMed1994

Radioimmunoscintigraphy of CEA/CA 19-9 producing tumors with I-131 labeled monoclonal antibodies.

A total of 7 (4 males and 3 females) patients were included in this retrospective study to determine the sensitivity of radioimmunoscintigraphy with I-131 labeled anti CEA/CA 19-9 monoclonal antibodies. Out of 7 patients 2 had ascending colon cancer, one had sigmoid colon cancer, one had rectal cancer and one had adenocarcinoma in the CBD and the remaining two had metastatic tumor (one in the lungs and the other in the liver). Whole body as well as spot images showed a 72% (5/7) positive scan. But post operative specimen counts and imaging showed a high tumor to non-tumor ratio and a good tumor to non-tumor contrast of activity of I-131 labeled monoclonal antibody. We did not find any relation between CEA/CA 19-9 levels and scan findings. A case of liver metastasis was also detected by this radioimmunoscintigraphy.

Adenocarcinoma↗

PubMed1994

Hepatitis C virus antibody and hepatitis C virus replication in chronic hepatitis B patients.

We assessed hepatitis C virus infection in 156 chronic hepatitis B patients using second-generation hepatitis C virus antibody (anti-HCV). Active virus replication was further investigated in anti-HCV-positive cases by means of polymerase chain reaction assay for the detection of serum hepatitis C virus RNA. Anti-HCV prevalence was higher in patients negative for hepatitis B e antigen (HBeAg) (10/48, 21%) than in HBeAg-positive patients (10/108, 9%) (p < 0.05), and the reactivity (cut-off index) in anti-HCV enzyme-linked immunosorbent assay of the positive cases was significantly higher in HBeAg-negative patients (4.1 +/- 0.1) than in -positive ones (3.6 +/- 0.6) (p < 0.05). The prevalence of hepatitis C virus RNA in anti-HCV-positive cases was also higher in the HBeAg-negative group (9/10, 90%) than in the -positive group (3/10, 30%) (p < 0.01). Viremia was found in association with high reactivity in anti-HCV ELISA (cut-off index > 3.5) in both groups. Nine (90%) of 10 such cases were viremic in the HBeAg-negative group compared with three (43%) of seven in the HBeAg-positive group (p < 0.05). These results suggest that hepatitis C virus replication may be influenced by hepatitis B virus replicative states, indicating possible interference between hepatitis B and C viruses.

Adult↗

PubMed1994

Characterization of the proximal promoter and two silencer elements in the CYP2C11 gene expressed in rat liver.

The cytochrome P450 gene CYP2C11, expressed in the liver of male rats, is transcriptionally regulated in a dual fashion by the sexually dimorphic secretion pattern of growth hormone. To enable analysis of transcriptional regulatory DNA elements, rat genomic sequences were cloned. DNase I hypersensitivity analysis of rat liver nuclei revealed the existence of two hypersensitive sites whose presence in the vicinity of the transcription start site correlates to high transcriptional activity of the gene. Deletion mutants of the 5' flank were fused to reporter genes and transiently transfected into HepG2 cells or into primary adult rat hypatocytes. Transfection experiments in combination with DNase I footprinting analysis in vitro led to the identification of two negative regulatory regions spanning nucleotides -1,230 to -1,188 and -409 to -368 and designated (SIL1200) and (SIL400), respectively. When placed in front of the heterologous thymidine kinase promoter, SIL1200 and SIL400 reduced the activity of the chloramphenicol acetyl transferase reporter gene to 13% and 23% of the control value, respectively. No sex-dependent binding of liver nuclear extracts to the two silencers could be detected by in vitro footprinting or gel retardation assays. However, a sex-dependent footprint consistently stronger with male liver nuclear extracts than with female extracts was observed in the -320 to -294 region. A significant level of identity was found between the DNA sequence corresponding to this footprint and that of orphan steroid receptor elements as well as with that of a basal transcription element common to several CYP2C genes. However, the identity of a potential trans-acting factor binding between -320 and -294 or response of this element to growth hormone is as yet unknown. A sex- and GH secretory profile-dependent protein-DNA interaction in vitro was observed in the -107 to -95 region. In spite of the sequence similarity that exists between this region and the consensus binding site for HNF-1, this region does not bind HNF-1 alpha. This element acted as a repressor on the heterologous thymidine kinase promoter. To date, the two silencer elements and possibly also the HNF-1-like element are the only functional elements defined in the CYP2C11 gene, and it is conceivable that induction of the gene involves derepression of the silencer elements.

Animals↗

PubMed1994

Interindividual difference in expression of human Ah receptor and related P450 genes.

The genomic clones of human aryl hydrocarbon receptor (Ahr) and Ahr nuclear translocator (Arnt) were isolated, and the structures of exon-intron junctions of these genes were partially determined. Based on the sequence information, a quantitative RT-PCR analysis was developed, and the expression of these genes was studied in various human tissues. mRNAs for Ahr and Arnt were widely expressed in human tissues and abundantly in lung. Individual difference in expression levels of Ahr and Arnt mRNA was observed in liver, lung and blood. In order to examine whether expression levels of Ahr and Arnt were associated with those of CYP1A1, we studied the expression of these mRNAs in blood among 20 healthy subjects, taking account of individuals' cigarette smoking habits. We found that the expression levels of CYP1A1 appeared to associate with those of Ahr and Arnt mRNAs (P < 0.06), and also that the expression of Ahr and Arnt was influenced by cigarette smoking. The expression of human Ahr and Arnt is reported here for the first time, providing a quantitative RT-PCR analysis as a useful tool for further studies.

Adult↗

PubMed1994

Platelet-activating factor acetylhydrolase in term and preterm human milk: a preliminary report.

Human milk may protect against necrotizing enterocolitis (NEC). Since platelet-activating factor (PAF) may participate in the pathophysiology of NEC, we measured PAF acetylhydrolase (PAF-AH), which metabolizes PAF, in term and preterm human milk. The activity of PAF-AH in term milk collected 2-4 days after delivery (n = 17) was 2.7 +/- 1.2 nmol x min-1 x ml-1. A higher activity was found in milk collected at similar times from mothers who delivered between 33 and 36 weeks of gestation (n = 6, 5.6 +/- 2.1 nmol x min-1 x ml-1, p < 0.01). However, milk from mothers who delivered between 26 and 32 weeks of gestation had a PAF-AH activity similar to that of term milk (n = 6, 3.0 +/- 0.7 nmol x min-1 x ml-1). With advancing lactational age, PAF-AH activity in term milk decreased, whereas the activity of this enzyme in preterm milk remained unchanged. In milk samples collected beyond 14 days after delivery from women who gave birth between 33 and 36 weeks or 26 and 32 weeks of gestation, PAF-AH activity was fivefold higher than that found in milk for women delivering at term (3.7 +/- 1.3 and 3.6 +/- 3.6 nmol x min-1 x ml-1 serum 0.7 +/- 0.4 nmol x min-1 x ml-1, respectively, p < 0.05). We speculate that the presence of PAF-AH in human milk may protect against NEC in preterm newborns.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗