Search PubMed⌕ Search

Biomedical subjects

C Itoh

Publications and source records attributed to C Itoh.

At least 19 recordsLinked to original sources
PubMed2000

Detection of an X-Ray Hot Region in the Virgo Cluster of Galaxies with ASCA.

Based on mapping observations with ASCA, an unusual hot region with a spatial extent of 1 deg2 was discovered between M87 and M49 at a center coordinate of R.A.=12h27m36s and decl.=9&j0;18' (J2000). The X-ray emission from the region has a 2-10 keV flux of 1x10-11 ergs s-1 cm-2 and a temperature of kT greater, similar4 keV, which is significantly higher than that in the surrounding medium of approximately 2 keV. The internal thermal energy in the hot region is estimated to be VnkT approximately 1060 ergs with a gas density of approximately 10-4 cm-3. A power-law spectrum with a photon index of 1.7-2.3 is also allowed by the data. The hot region suggests there is an energy input due to a shock that is probably caused by the motion of the gas associated with M49, infalling toward the M87 cluster with a velocity greater, similar1000 km s-1.

Journal Article↗
PubMed2000

Use of crypt isolation to determine loss of heterozygosity of multiple tumor suppressor genes in colorectal carcinoma.

Analysis of loss of heterozygosity (LOH) is very important in the study of tumor suppressor genes. However, accurate LOH analysis of tumor suppressor genes is difficult because of dilution by contaminating non-tumor DNA. Thus, enrichment of tumor DNA is required to accurately determine LOH of the tumor. We developed a new application of the fluorescent polymerase chain reaction by coupling it with crypt isolation to accurately assess the incidence of LOH of tumor suppressor genes in 45 colorectal carcinomas. LOH was observed at p53 in 26 of 37 tumors (70.3%), at APC in 13 of 35 (37.1%), at DCC in 16 of 25 (64.0%), at NF-2 in 5 of 23 (21.7%), and at nm23 H-1 in 7 of 30 (23.3%). We could clearly determine LOH of these genes because the crypt isolation technique was used. Although the incidence of LOH at each of these loci, as determined by using this technique, was similar to that obtained in previous studies using conventional methods, this method provides a simpler, more accurate way to assess LOH. In addition, the morphology of the samples can be analyzed before genetic analysis.

Adenocarcinoma, Mucinous↗
PubMed2000

Genetic polymorphism of 5,10-methylenetetrahydrofolate increases risk of myocardial infarction and is correlated to elevated levels of homocysteine in the Japanese general population.

BACKGROUND: Hyperhomocysteinemia, an independent and graded risk factor for coronary artery disease, can result from both environmental and hereditary factors. C677T mutation of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene [alanine/valine (A/V) polymorphism], one of the key enzymes involved in catalyzing the remethylation of homocysteine, has recently been reported. OBJECTIVE: To evaluate the incidence of the MTHFR genotypes and their significance in determining the risk for myocardial infarction of Japanese men. METHOD: The subjects consisted of 199 healthy men (mean age, 60 years) and 230 male patients with myocardial infarction (mean age, 59 years). The coronary-artery lesions were evaluated by coronary angiography. The MTHFR genotype was analyzed by polymerase chain reaction and then by digestion with Hinfl. Total plasma levels of homocysteine for each MTHFR genotype were compared with those in healthy controls. RESULTS: The prevalences of the A and V alleles among the healthy male subjects were 0.652 and 0.348 in the Hardy-Weinberg equilibrium. The total levels of homocysteine in the plasma of the healthy male subjects were 8.6 +/- 3.3, 8.9 +/- 4.1, and 11.6 +/- 5.6 mumol/l, for AA, AV, and VV genotypes, respectively. Individuals with the VV homozygous mutant genotype thus had the highest plasma levels of homocysteine. Logistic analysis revealed that the levels of high-density lipoprotein cholesterol, hypertension, diabetes mellitus, MTHFR VV genotype, and triglycerides were all independent risk factors for myocardial infarction. The VV genotype was more prevalent among patients with myocardial infarction (mean age, 59 years) than it was among the control subjects (17.0 versus 10.6%, P < 0.05). However, there were no differences in the numbers of stenotic coronary arteries among the MTHFR genotypes. CONCLUSION: The VV genotype of MTHFR increases plasma levels of homocysteine in healthy controls, and this mutation indicates a genetic predisposition toward a greater than normal risk of myocardial infarction for Japanese men.

Cohort Studies↗
PubMed2000

A unique method for mutation analysis of tumor suppressor genes in colorectal carcinomas using a crypt isolation technique.

BACKGROUND: Contamination of nontumor tissue makes genetic analysis difficult. For this reason, it is important to obtain pure tumor tissue to ensure accurate genetic analysis. OBJECTIVE: To accurately assess the incidence of mutation of tumor suppressor genes (p53: exon 5-8; APC: mutated cluster region; NF-2 gene: all exons) in 45 colorectal carcinomas. METHODS: We developed an application of the polymerase chain reaction-single-strand conformation polymorphism and DNA sequence by coupling them with crypt isolation. RESULTS: Mutations of p53 and APC genes were found in 24 and 22 of 45 colorectal carcinomas, respectively. No mutation of the NF-2 gene was observed in this cancer. Single-strand conformation polymorphism using a crypt isolation technique showed a clear migrating band and no false-positive data. CONCLUSIONS: The crypt isolation technique is a useful method for accurately analyzing genetic alterations. Furthermore, our proposed method confirmed the morphological findings obtained before the genetic analysis.

Adenocarcinoma↗
PubMed2000

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group].

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

Anti-Infective Agents↗
PubMed1999

Role of DNA aneuploidy, overexpression of p53 gene product, and cellular proliferation in the progression of gastric cancer.

DNA aneuploidy, p53 overexpression, and high cell proliferation frequently occur in gastric cancer. However, little is known about the time of their appearance throughout cancer progression. Therefore, the objective of the present study was to determine when such abnormalities occur during gastric cancer progression. We classified the gastric cancers examined into intestinal (n = 65) and diffuse (n = 34) types. DNA ploidy was examined using flow cytometry and expression of MIB-1 and p53 immunoreactivity were studied using the avidin-biotin complex method in three stages of gastric cancer (mucosal, submucosal, deeply invasive cancer, i.e., advanced cancer). The incidence of DNA aneuploidy in intestinal-type mucosal cancers (15/27, 55.6%) was lower than that of submucosal invasive cancers (14/16, 87.5%) or advanced cancers (19/22, 86.4%), while a low incidence of DNA aneuploidy was observed in each diffuse-type cancer group (mucosal, 1/12, 8.3%; submucosal invasive, 3/9, 33.3%; advanced, 8/14, 57.1%). Although overexpression of the p53 gene in intestinal-type cancer was found in early stage, that in diffuse-type cancer was observed in advanced stage. Among the intestinal-type mucosal cancers, the MIB-1 percent positive was higher in aneuploid tumors than diploid ones. DNA aneuploidy and overexpression of the p53 gene may play an important role in the early tumorigenesis of intestinal-type gastric cancer and in the late event of tumorigenesis of diffuse-type gastric cancer.

Aged↗
PubMed1999

Analysis of subclonal expansion of colorectal carcinomas by flow cytometry.

DNA heterogeneity of colorectal carcinomas has been investigated by flow cytometry, most studies have focused on the clinical usefulness of DNA ploidy analysis. Since cancers consist of predominant subclones with proliferative advantage due to clonal expansion, we attempted to analyse the clonal expansion of colorectal carcinomas within a tumour by measuring DNA ploidy. The DNA ploidy and heterogeneity of multiple fresh samples obtained from 164 colorectal adenocarcinomas were analysed by flow cytometry. Each tumour was divided into an average of six specimens, which were analysed separately. For 146 of the tumours (89%) at least one DNA aneuploid population was found within the cancer tissue examined. DNA multiploidy was detected in 26 cases (17.8%) among the cancers with aneuploidy. Based on the DNA index (DI), hypertriploid aneuploidy (1.7<DI<1.8) was found most frequently in the aneuploid colorectal cancers examined. DNA ploidy heterogeneity was seen in 75 (51.4%) of the DNA aneuploid tumours. There were only 3 cases with more than three subclones including a diploid line. The present results indicate that colorectal carcinomas consist of a few dominant subclones and have a DNA content (hypertriploid aneuploid) that confers a proliferative advantage.

Adenocarcinoma↗
PubMed1999

Case report of lymphoepithelioma-like carcinoma of the lung--lymphoid population consisting of cytotoxic T cells in resting state.

The present report describes a case of lymphoepithelioma-like carcinoma (LELC) of the lung and presents immunohistochemical and in situ hybridization (ISH) studies of the tumor. A 39-year-old Chinese woman, who was born in China and emigrated to Japan at the age of 29, suffered from a cough for 2 years and received a middle and lower lobectomy with mediastinal lymph node dissection after induction chemotherapy. The tumor consisted of undifferentiated carcinoma and areas of more differentiated squamous cell carcinoma with an intense lymphoid infiltrate. Serological studies and ISH studies showed EBV infection of the tumor. The immunophenotype of tumor-infiltrating T-lymphocytes (TITL) of the present case was examined immunohistochemically and was compared with that of an LELC case reported previously. Most CD3-positive T cells of TITL in both cases were labeled with both CD8 and TIA-1 but not with granzyme-B, indicating the TITL to be cytotoxic T lymphocytes (CTL) in the resting state. The lack of CTL activation at the tumor site might have been due to local inhibition of EBV-specific CTL responses such as T-cell anergy. Because the EBV-specific CTL derived from peripheral blood lymphocytes, in contrast to the TITL, may not be influenced by either tumor-produced suppressor factors or negative regulatory T cells, they may inhibit the hematogenous metastasis of EBV-positive LELC, possibly resulting in a better prognosis. Because LELC of the lung responded to preoperative chemotherapy in the present study, it may be useful for reducing the local tumor burden and facilitate subsequent local therapy, although the mechanism of chemosensitivity of LELC remains unknown.

Adult↗
PubMed1999

Multiple red blood cell antibodies produced by donor B lymphocytes after ABO-matched allogeneic bone marrow transplantation.

A 50-year-old man with AML[M2,t(8;21)] underwent BMT from his younger sister. At that time, he had no unexpected antibody and his blood type was O(+), CcDEe. The type of Kidd was not examined. The donor's blood type was O(+), CCDee, Jk(a+b-). One year after the BMT, the patient's blood type had changed to that of the donor's and anti-E antibody was detected. Despite the use of platelet concentrates (PCs) only, anti-c antibody was later identified. We conclude that there is a need to check red cell antibodies at regular intervals, even when using PCs only, for earlier detection of unexpected antibodies after BMT.

ABO Blood-Group System↗
PubMed1999

[Lymphoepithelioma-like carcinoma of the lung].

Lymphoepithelioma-like carcinoma of the lung was diagnosed in a 39-year-old Chinese woman. In situ hybridization of Epstein Barr virus-encoded small nuclear RNA 1 (EBER 1) detected strong EBER 1 signals in the nuclei of tumor cell specimens from the patient. After polymerase chain reaction (PCR) amplification, electrophoresis identified the IR-1 region in this tumor as a positive sharp band, closely resembling Raji cells (Burkitt's cell line). The uniform and intense presence of EBER 1 in the tumor nuclei and the PCR products of EBV DNA in the tumor demonstrated that a high copy number of EB virus genome existed in the tumor, and indicated involvement of the EB virus in the pathogenesis of lymphoepithelioma-like carcinoma of the lung.

Adult↗
PubMed1999

A Fe(3+)/DNA complex induces an anti-human immunodeficiency virus factor(s) in CD4+ lymphocyte cell lines.

Numerous cytokines and chemokines are involved in inflammatory and immune response. Whereas some of them inhibit virus replication in vitro directly or increase the patients' T4-lymphocyte level, others effects are not so clear. Using human immunodeficiency virus (HIV) and cell cultures we have studied the antiviral effect of complexes of salmon DNA with metals and of a new factor(s) (antiviral factor, AVF) induced in cells by the complexes. The Fe3+/DNA complex possessed the highest antiviral activity. It was found that MT-2, MT-4, CEM and Jurkat cells treated with the complexes secreted AVF which inhibited the replication of nine HIV-1 isolates, was noncytotoxic and stimulated cell proliferation. AVF did not inactivate HIV. The molecular mass analysis of AVF showed that its antiviral activity is associated with its fraction of M(r) of 3 K. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of mRNA from MT-4 cells treated with the complexes showed an increase in the the expression of genes for interleukin-1 alpha (IL-1 alpha), tumour necrosis factor alpha (TNF-alpha) and TNF-beta while expression of genes for IL-1-beta, IL-2, IL-4, IL-6, IL-8. IL-10, IL-12; 35p, 40p, IL-13, GMCSF, GSF and RANTES was not detected at all. However, the anti-HIV activity of the cell culture supernatant in vitro cannot be explained by mere presence of the inflammatory substances mentioned above, because they do not possess such activity and their M(r) is higher than that of AVF. Our findings raise the possibility that AVF(s) may be involved in the mechanism of cell resistance against HIV.

Animals↗
PubMed1998

Correlation of histologic morphology and tumor stage with molecular genetic analysis using microdissection in gastric carcinomas.

Precise correlation of histomorphology with the results of molecular genetic analysis is difficult in gastric cancer tissue composed of intestinal and diffuse types. A novel microdissection procedure was applied to correlate p53 and APC allelic loss with histologic type and tumor stage (mucosal vs. invasive cancer) in formalin-fixed, paraffin-embedded specimens of 25 gastric cancers. In addition, mucosal and invasive lesions were dissected from each of 11 invasive gastric cancers to study progression, and allelic loss of the p53 and APC genes was assessed. The p53 gene underwent loss of heterozygosity (LOH) in 4 of 4 informative cases of intestinal-type gastric cancer with mucosal lesions associated with invasion. By contrast, no p53 LOH was found among 6 informative cases with mucosal cancer. LOH of the APC gene in both intestinal and diffuse types of cancer was detected in 4 of 7 and 5 of 6 informative cases, respectively. These data suggest that allelic deletion of the p53 gene in intestinal-type gastric carcinoma predicts the invasive potential of mucosal cancer, and that inactivation of the APC gene plays a role in the genetic tumorigenesis of both intestinal and diffuse types of gastric cancer. Microdissection can correlate genetic alterations with histologic morphology in gastric cancer.

Adenocarcinoma↗
PubMed1997

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram. RESULTS: Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01). CONCLUSIONS: The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Adult↗
PubMed1997

Two molecular species of oxytocinase (L-cystine aminopeptidase) in human placenta: purification and characterization.

Two different forms of oxytocinase (L-cystine aminopeptidase, CAP; EC 3.4.11.3) were purified from the 9000 g and 105000 g precipitate fractions of human placenta homogenate by sequential chromatography on columns of hydroxyapatite, DE-32, nickel ion affinity, and Sephadex G-200. One species (CAP-I) purifed from the mitochondrial/lysosomal fraction migrated on sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis with an apparent molecular mass of 61 kDa; the other (CAP-II) from the microsomal fraction was composed of two subunits with molecular masses of 56 and 40 kDa. The molecular masses of CAP-I and CAP-II estimated by gel filtration were 64 and 97 kDa, respectively. The specific activities of the two species for S-benzyl-L-cysteine p-nitroanilide increased by 357- (for CAP-I) and 139-fold (for CAP-II) compared with the starting preparations. The optimal pH values toward the artificial substrate were approx. 7.4-8.0 for CAP-I and 6.8-8.0 for CAP-II. The Km and Vmax values toward oxytocin were 5.6 microM and 23.4 micromol/h/mg protein for CAP-I, and 38 microM and 15.6 micromol/h/mg protein for CAP-II. Both enzymes were inhibited by the metal-chelating agents, EDTA and o-phenanthroline, whereas they were specifically activated by addition of Co2+: CAP-I was more sensitive to these reagents than CAP-II. L-Methionine strongly inhibited CAP-I, while CAP-II activity was only slightly affected. CAP-II was more sensitive to amastatin than CAP-I. Thus, the two enzymes are quite distinct in their molecular nature and biochemical properties. They may play a regulatory role in the metabolism of oxytocin and other biologically active peptides in intact placenta.

Cystinyl Aminopeptidase↗