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Biomedical subjects

M Ito

Publications and source records attributed to M Ito.

At least 145 records · Page 8Linked to original sources
PubMed2002

Role of anti-parietal cell antibody in Helicobacter pylori-associated atrophic gastritis: evaluation in a country of high prevalence of atrophic gastritis.

BACKGROUND: Helicobacter pylori plays an important part in the progression of atrophic gastritis; however, markers for predicting the progression of atrophic gastritis remain unidentified. We investigated the relation between the degree of atrophic gastritis and the amount of anti-parietal cell antibodies (APCAs) present. METHODS: In 219 Japanese patients, APCA was investigated by enzyme-linked immunosorbent assay (ELISA) and by Western blotting. The grade of corpus atrophy was estimated by histology and serum pepsinogen levels. Serum levels of pepsinogen were evaluated by radioimmunoassay. RESULTS: Helicobacter pylori infection did not affect the APCA levels determined by ELISA. Long-term administration of proton-pump inhibitors and H. pylori eradication did not influence the levels of APCAs. However, in H. pylori-positive patients, the levels of APCA determined by ELISA were statistically higher in patients with severe atrophy than in those with mild atrophy as determined histologically (0.67+/-0.48 versus 0.45+/-0.40; A492, mean+/-s, P=0.01) and serologically by pepsinogen levels (0.66+/-0.51 versus 0.44+/-0.40. P=0.002). The levels of pepsinogen I/II ratio were correlated with APCA levels only in the H. pylori-positive group. Western blotting showed that major antigen was identical with the beta-subunit of H+,K+-ATPase. CONCLUSION: APCA plays an important part in the progression of corpus atrophy after H. pylori infection.

Adolescent↗
PubMed2002

Expression of glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase in a case of pulmonary epithelioid haemangioendothelioma.

This report describes a case of pulmonary epithelioid haemangioendothelioma in which the tumour cells expressed the glucocorticoid receptor and 11beta-hydroxysteroid dehydrogenase. The patient, a 15 year old girl, who had no other complaints or past illnesses, was found to have an abnormal shadow on a chest roentgenogram obtained at a school medical examination. Multiple nodular shadows in the bilateral lungs were also confirmed by computerised axial tomography scan. A diagnosis of pulmonary epithelioid haemangioendothelioma was made on the basis of lung biopsy specimens. The tumour cells were immunohistochemically positive for factor VIII related antigen, CD31, and CD34, but not surfactant apoprotein A. In addition, almost all of the tumour cells showed simultaneous expression of the glucocorticoid receptor and 11beta hydroxysteroid dehydrogenase, suggesting that steroid treatment would be effective.

11-beta-Hydroxysteroid Dehydrogenases↗
PubMed2002

Nonrandom X chromosome inactivation in mouse embryos carrying Searle's T(X;16)16H translocation visualized using X-linked LACZ and GFP transgenes.

Only the morphologically normal X chromosome is inactivated in female mice heterozygous for Searle's X-autosome translocation, T(X;16)16H. Here we performed a visual study of the primary and secondary events that culminate in the completely nonrandom inactivation of the X in female embryos having this translocation. The data we have obtained so far indicate that the initial choice of the future inactive X chromosome is biased, with the degree of skewing somewhere between 70:30% and 90:10% in favor of the morphologically normal X chromosome. The majority of genetically unbalanced cells that inactivate a translocated X chromosome are quickly eliminated from the embryo proper by E8.5, although the survival of such cells is sporadically observed thereafter. The initial nonrandom choice demonstrated in this study supports the contention that the T(X;16)16H translocation disrupts one of the loci involved in the randomness of the choice of the future inactive X chromosome. Although the HMG-LACZ transgene in H253 stock mice is an excellent marker of X chromosome inactivation, the present study suggests that it is infrequently de-repressed on the inactive X chromosome.

Animals↗
PubMed2002

Recovery of rats with fulminant hepatic failure by using a hybrid artificial liver support system with polyurethane foam/rat hepatocyte spheroids.

We studied the recovery of rats with fulminant hepatic failure (FHF) by treating them with our original hybrid artificial liver support system (HALSS). FHF was induced by a two-thirds partial hepatectomy and 10 minutes of hepatic ischemia. Rats with FHF were treated with a polyurethane foam/spheroid HALSS including 2.0 x 10(8) hepatocytes for 1 hour (HALSS group, n = 5), and with the same system without hepatocytes in the artificial liver module as a control experiment (sham-HALSS group, n = 3). The level of blood constituents, ammonia, glucose and creatinine, showed no major difference between the two groups at the end of treatment. All rats in the sham-HALSS group died within 5 hours after treatment. However, the level of blood constituents of rats with FHF in the HALSS group improved with time, and all rats in the HALSS group recovered. Liver tissue of rats treated with HALSS showed cell mitosis and improvement from injury. These results indicated that our HALSS has a strong possibility to induce recovery from hepatic failure.

Ammonia↗
PubMed2002

[Esophageal rupture just after the graft replacement of thoracoabdominal aorta for chronic aortic dissection].

A 51-year-old man with thoracoabdominal aortic aneurysm (DeBakey IIIb type chronic aortic dissection) first underwent the graft replacement of thoracic aorta with elephant trunk technique. Postoperatively, the residual false lumen just distal to the inserted graft as an elephant trunk enlarged in a short period, and it compressed the esophagus. He underwent the second graft replacement of thoracoabdominal aorta 2 months after the first surgery. Just after the second surgery, he had the esophageal rupture probably because of direct damage due to the enlarged aneurysm and loss of the arterial blood supply due to the graft replacement. He died of bleeding from the distal anastomosis because of the uncontrolled graft infection. It may have to be kept in mind that the esophageal rupture after the graft replacement could be one of the reason of the graft infection when the aortic aneurysm severely compressed the esophagus preoperatively.

Aortic Dissection↗
PubMed2001

Iron deficiency anemia increases nitric oxide production in healthy adolescents.

To investigate the influence of iron deficiency and iron supplementation on nitric oxide (NO) production, we measured serum iron markers, serum nitrate and nitrite (NOx) concentrations, reticulocyte maturity index (RMI), and serum transferrin receptor (sTfR) levels in 369 females aged 14-19 years. RMI was analyzed by flow cytometry, sTfR concentrations were measured by enzyme immunoassay, and serum NOx levels were tested by the Griess reaction. NOx concentrations of the subjects in iron depletion phase were significantly higher than those of healthy controls. NOx concentrations increased gradually as iron deficiency progressed and were threefold higher than for the healthy controls, when the subjects attained a frank iron deficiency anemia. In particular, the NOx concentrations were 7.5-fold higher in the patients with severe iron deficiency anemia (Hb<80 g/l) than for the subjects with high hemoglobin value (Hb>or=140 g/l). The increased NOx concentrations (132.6+/-42.1 microM) observed in the group with severe anemia decreased significantly (46.3+/-15.8 microM) after hemoglobin levels were normalized by iron supplementation ( P<0.01). NOx concentrations correlated inversely with hemoglobin levels ( r(2)=0.202, P<0.01), but correlated positively with the sTfR concentrations ( r(2)=0.322, P<0.01) and the RMI ( r(2)=0.369, P<0.01). In conclusion, iron deficiency anemia increases NO production, and elevated NOx concentrations in iron deficiency anemia return to normal with iron supplementation.

Adolescent↗
PubMed2001

Squalene synthase inhibitors reduce plasma triglyceride through a low-density lipoprotein receptor-independent mechanism.

Inhibitors of squalene synthase are considered to be candidate drugs to reduce both plasma cholesterol and triglyceride. However, little is known about the mechanism of squalene synthase inhibitor-specific effect on plasma triglyceride. In this study, we confirmed the triglyceride-lowering effect of ER-27856, a potent squalene synthase inhibitor prodrug, in rhesus monkeys. To determine the role of low-density lipoprotein (LDL) receptor in the triglyceride-lowering effect of squalene synthase inhibitors, we intravenously administered ER-28448, the active form of ER-27856, to Watanabe heritable hyperlipidemic (WHHL) rabbits for 4 days. In heterozygotes, ER-28448 reduced plasma cholesterol and triglyceride by 52% and 37%, respectively. In homozygous rabbits, in contrast, ER-28448 lowered plasma triglyceride by 40% but did not lower plasma cholesterol. Orally administered ER-27856 reduced plasma triglyceride in homozygous animals but atorvastatin and bezafibrate did not. In hepatocytes isolated from homozygous WHHL rabbits, squalene synthase inhibitors but not atorvastatin reduced triglyceride biosynthesis. These data demonstrate that squalene synthase inhibitors reduced plasma triglyceride through an LDL receptor-independent mechanism, which was distinct from that of the triglyceride-lowering action of atorvastatin or bezafibrate. The reduction of hepatic triglyceride biosynthesis may play an important role in the hypotrigyceridemic action of squalene synthase inhibitors.

Animals↗
PubMed2001

Involvement of ADAM9 in multinucleated giant cell formation of blood monocytes.

Monocytes-macrophages are converted to multinucleated giant cells by stimulation with various cytokines, and osteoclasts are the multinucleated giant cells derived from a monocyte-macrophage lineage. However, at present, the fusion peptides have not been clearly identified in monocytes-macrophages. The ADAM are a family of transmembrane glycoproteins that have a role in various biological functions. Interestingly, fertilin-alpha, ADAM9, and ADAM11 have potential fusion peptides. In this study, which ADAM was specifically expressed in monocytes stimulated with anti-CD98 antibody or RANKL and which factor(s) was functioning in monocytes as a fusion protein were investigated. ADAM1, 8, 10, 12, 15, 17, 20, and 21 mRNAs are expressed in blood monocytes incubated with control antibody, anti-FRP-1/CD98 antibody, or RANKL + M-CSF, while ADAM2, 7, 11, 13, 19, 23, 29, and 30 mRNAs could not be detected in these blood monocytes. Expression of ADAM9 and ADAM10 mRNAs are enhanced by either RANKL + M-CSF or anti-CD98 antibody. The expression of ADAM9 and ADAM10 is also induced in blood monocytes by anti-CD98 mAb. An anti-ADAM9 antibody enhances CD98-mediated cell aggregation, while it blocks CD98-mediated and RANKL-mediated multinucleated giant cell formation. A hydroxamate-based metalloprotease inhibitor, SI-27, which is found to suppress ADAM9 activity, suppresses multinucleated giant cell formation. New protein synthesis is necessary for the expression of ADAM9 mRNA and genistein suppresses induction of ADAM9 mRNA. This is the first report that ADAM9 is involved in monocyte fusion, such as CD98-mediated and RANKL-mediated cell fusion of blood monocytes. Furthermore, AMAM9 is one candidate for a fusion peptide in blood monocytes.

ADAM Proteins↗
PubMed2001

Overexpression of AML1 transcription factor drives thymocytes into the CD8 single-positive lineage.

To understand the gene regulation involved in the development of single-positive (SP) thymocytes, we generated transgenic mice in which the AML1 transcription factor is overexpressed. In these mice the number of CD8 SP thymocytes was greatly increased, and this continued to be true even when MHC class I was absent. This promotion to the CD8 SP lineage was not, however, observed when both class I and class II were absent. Furthermore, even thymocytes carrying MHC class II-restricted TCR differentiated into the CD8 SP lineage when AML1 was overexpressed. The selected CD8 SP cells were, however, unable to mature, as judged by the expression level of heat-stable Ag. Thus, overexpression of AML1 is able to skew class II-restricted thymocytes into the CD8 SP lineage, but not to drive the maturation of resulting selected CD8 SP cells.

Animals↗
PubMed2001

Temperature-sensitive phenotype of Chinese hamster ovary cells defective in PEX5 gene.

SK32 mutant cells, which were isolated as peroxisome-deficient Chinese hamster ovary (CHO) cells by an advantage of a visible peroxisome form of green fluorescent protein (GFP), were found to suffer from a functional loss of PEX5 gene encoding for PTS1R. The sequence analysis of cDNA indicated that PEX5 gene encoded for the two isoforms composed of 603 amino acids (PTS1RS) and 640 amino acids (PTS1RL). The mutation changed glycine to arginine at amino acid position 343 of PTS1RL (corresponding to the position 306 of PTS1RS) in SK32 cells. The mutant cells exhibited a temperature-sensitive (TS) phenotype on the peroxisomal localizations of the recombinant GFP and urate oxidase appending a genuine peroxisome targeting signal 1 (PTS1), a tripeptide of Ser-Lys-Leu (SKL) at the C-terminus, but did not on that of catalase harboring a divergent PTS1, Lys-Ala-Asn-Leu (KANL) sequence. 3-ketoacyl-CoA thiolase (hereafter referred to as thiolase), which harbors an extension sequence (PTS2) at the N-terminus, never appeared to be affected on the peroxisomal localization in the mutant cells. When thiolase was examined on the molecular size in the mutant cells, the enzyme existed as the larger precursor form in the peroxisomes at 37 degrees C and a considerable part (almost half) was converted to the mature size at 30 degrees C. These results indicate that the amino acid substitution, Gly306Arg in PTS1RS and/or Gly343Arg in PTSRL, gives rise to TS phenotype on the peroxisomal translocation of PTS1 proteins and the maturation of PTS2 protein.

Amino Acid Sequence↗
PubMed2001

Identification of Lck-derived peptides capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients with distant metastases.

The Lck protein (p56(lck)), a src family tyrosine kinase essential for T cell development and function, is aberrantly expressed in various types of cancers. We revealed recently that Lck can be a tumor antigen recognized by HLA-A24-restricted and tumor-specific cytotoxic T lymphocytes (CTLs) of cancer patients with metastases. In this study, we tried to identify Lck-derived epitopes capable of inducing HLA-A2-restricted and tumor-specific CTLs in cancer patients. The tumor-infiltrating lymphocytes (TILs) from 2 HLA-A2 cancer patients were found to respond to COS-7 cells when co-transfected with the lck gene and either HLA-A0201, -A0206, or A0207 cDNA. These TILs contained CTLs capable of recognizing either the Lck(61-69), the Lck(246-254), or the Lck(422-430) peptide among 24 different peptides, all of which were prepared based on the HLA-A2 binding motif. Importantly, in vitro sensitization with the latter 2 peptides induced tumor-specific CTLs in HLA-A2(+) cancer patients with metastases, but not in those without metastases. Overall, the Lck(246-254) and Lck(422-430) peptides could be useful for specific immunotherapy of HLA-A2(+) cancer patients, especially with distant metastases.

Animals↗
PubMed2001

Effects of therapeutic doses of human atrial natriuretic peptide on load and myocardial performance in patients with congestive heart failure.

The benefits of atrial natriuretic peptide (ANP) in patients with congestive heart failure (CHF) have been demonstrated. However, the myocardial actions of ANP remain unclear. Using relatively load-insensitive left ventricular pressure-volume analysis, the myocardial and load-altering actions of ANP in patients with moderate CHF were studied. After obtaining steady-state data using micromanometers and conductance catheters, ANP was infused in 9 patients with CHF at 0.01 and 0.1 microg/kg/min for 30 minutes, respectively. Hemodynamic variables, plasma ANP, and cyclic guanosine monophosphate (cGMP) levels were determined before and 30 minutes after each ANP infusion. ANP at 0.01 microg/kg/min increased plasma ANP and cGMP levels from 73 +/- 34 to 139 +/- 34 pg/ml and from 4 +/- 1 to 8 +/- 2 pmol/ml, respectively. ANP infusion caused a significant decrease in end-systolic pressure without any changes in heart rate. End-diastolic pressure was significantly decreased but there was no significant change in left ventricular end-diastolic volume. The time constant for isovolumetric relaxation was decreased. ANP infusion at 0.1microg/kg/min caused further decreases in end-systolic pressure, end-diastolic pressure and volume, and the time constant for isovolumetric relaxation (p <0.05) without any changes in heart rate. The slope of the end-systolic pressure-volume relation was increased from 1.3 +/- 0.2 to 1.6 +/- 0.3 mm Hg/ml (p <0.05), indicating increased contractility. Plasma ANP and cGMP levels were increased to 422 +/- 44 pg/ml and 16 +/- 3 pmol/ml, respectively. Thus, ANP infusion increased cGMP generation, decreased afterload and preload, and improved left ventricular systolic and diastolic function.

Atrial Natriuretic Factor↗
PubMed2001

Localization of neutral ceramidase in caveolin-enriched light membranes of murine endothelial cells.

Sphingomyelinase (SMase) and ceramidase (CDase) activities participate in sphingomyelin (SM) metabolism and have a role in the signal transduction of a variety of ligands. In this study evidence is presented that caveolin-enriched light membranes (CELMs) of murine endothelial cells, characterized by high SM, ceramide (Cer) and cholesterol content, bear acid and neutral SMase as well as neutral CDase activities. Localization of neutral CDase in CELMs was confirmed by Western analysis. Notably, cell treatment with cyclodextrin, which depleted cell cholesterol, did not affect acid or neutral SMase activities but significantly enhanced neutral CDase activity in CELMs, indicating a negative role for cholesterol in CDase regulation. These findings suggest that neutral CDase is implicated, together with SMase activities, in the control of caveolar Cer content that may be critical for caveola dynamics.

Amidohydrolases↗
PubMed2001

Molecular events involved in up-regulating human Na+-independent neutral amino acid transporter LAT1 during T-cell activation.

We investigated the regulation of system-L amino acid transporter (LAT1) during T-cell activation. In quiescent T-cells, L-leucine transport is mediated mainly by the system-L amino acid transport system and is increased significantly during T-cell activation by PMA and ionomycin. In quiescent T-cells, the LAT1 protein was heterocomplexed with 4F2 heavy chain (4F2hc) in the plasma membrane. During T-cell activation, the amounts of 4F2hc and LAT1 heterocomplex were significantly elevated compared with those in quiescent T-cells. In addition, by Northern-blot analysis, these increments were found to be due to elevated levels of LAT1 and 4F2hc mRNA. Transient expression of constructs comprising various LAT1 gene promoter fragments, which contained all three of the GC boxes, was sufficient for promoting luciferase expression in Jurkat T-cells, but the promoter of the LAT1 gene did not respond to PMA and ionomycin. Similar observations were observed in the human 4F2hc gene promoter. In nuclear run-on assay, the LAT1 and 4F2hc genes were actively transcribed even in quiescent T-cells, but the low levels of both transcripts were shown to be the result of a block to transcription elongation within the exon 1 intron 1 regions. These findings indicated that a removal of the block to mRNA elongation stimulates the induction of system-L amino acid transporter gene transcripts (LAT1 and 4F2hc) in activated T-cells.

Amino Acid Sequence↗
PubMed2001

Nav1.1 mutations cause febrile seizures associated with afebrile partial seizures.

Recent evidence has suggested that the neuronal voltage-gated sodium channel alpha(1)-subunit gene (Na(v)1.1: SCN1A) is responsible for generalized epilepsy with febrile seizures plus (GEFS+2). Here the authors report two novel disease mutations of Na(v)1.1 in patients with febrile seizures associated with afebrile partial seizures. One is a Val1428Ala substitution in the pore-forming region, and the other is Ala1685Val in the transmembrane helix. These results support the previous findings and contribute to the reliable diagnosis of epilepsy.

Amino Acid Sequence↗