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Biomedical subjects

K Itoh

Publications and source records attributed to K Itoh.

At least 649 records · Page 36Linked to original sources
PubMed1996

Higher susceptibility of erythropoietin-producing renal cell carcinomas to lysis by lymphokine-activated killer cells.

Erythropoietin production by renal cell carcinoma (RCC) is reported to be a potential marker for interleukin-2/interferon-alpha-responding tumor. We have investigated whether erythropoietin of RCC cells is involved in the immune recognition by lymphokine-activated killer (LAK) cells. Cells from primary culture of RCC cells expressing erythropoietin-mRNA or producing erythropoietin were more susceptible to lysis by LAK cells than those not expressing or producing it, respectively. RCC cells transfected with erythropoietin-cDNA became more susceptible to lysis by LAK cells than their erythropoietin-negative parental cells. These results indicate higher susceptibility of erythropoietin-producing RCC cells to lysis by LAK cells, suggesting that erythropoietin of RCC cells is involved in the immune recognition by LAK cells.

Carcinoma, Renal Cell↗
PubMed1996

Bone SPET of symptomatic lumbar spondylolysis.

The aim of this study was to clarify the clinical role of bone single photon emission tomography (SPET) of the lumbar spine in young persons with persistent lumbar pain which might be due to spondylolysis. Thirty-one bone SPET studies were performed on 25 patients (19 males, 6 females) aged 7-26 years (average 15.6 years) who had suffered lumbar pain associated with physical activity, and who were suspected of having spondylolysis. Planar and SPET images of the lumbar spine were obtained 2-3 h following the injection of 99Tc(m)-methylene diphosphonate using a single-head rotating gamma camera. The findings on the bone scintigram were compared with those on the radiograph. Bone scintigraphy at presentation was positive in only 7 of 15 sites of the pars interarticularis defects demonstrated on plain radiographs. On the other hand, seven sites of the pars interarticularis which were normal on the radiograph were positive on bone SPET. As clinical symptoms improved after immobilization using a lumbar corset, bone SPET tended to revert towards normal. The planar image was abnormal in only 8 (42%) of the 19 abnormal sites on the SPET image. A bone SPET study is indicated in patients who are negative on radiological tests and who are still suspected of having spondylolysis. If SPET is positive in these patients, the increased bone uptake is most likely suggestive of a state of 'stress reaction', and may be a good indicator for patient management. If negative, further radiological examinations will be required for proper assessment of the origin of lumbar pain.

Adolescent↗
PubMed1996

Selective growth of human melanoma cells in the brain parenchyma of nude mice.

The purpose of this study was to determine whether the growth of human melanoma cells in the brain parenchyma is selective and represents the growth of unique cells. Six human melanoma cell lines derived from cutaneous lymph node or brain metastases (from six different patients) and melanoma cells isolated from fresh surgical specimens of two primary cutaneous melanomas, two lymph node metastases and two brain metastases (each from a different patient) were injected into the subarachnoid space of nude mice. All melanomas produced growths in the leptomeninges, but only melanoma cells isolated from brain metastases infiltrated into and grew in the brain parenchyma of nude mice. The results from in vitro assays for cell motility or production of gelatinase activity did not correlate with in vivo growth pattern. However, the in vitro growth of human melanoma cells in the presence of TGF-beta 2 inversely correlated with potential for brain parenchyma metastasis, i.e. the growth of cells from brain metastases was least inhibited by TGF-beta 2. These data suggest that melanoma brain parenchyma metastases are produced by unique cells that may be resistant to the antiproliferative effects of TGF-beta 2.

Animals↗
PubMed1996

In vitro effects of immunosuppressive agents on cytokine production by HTLV-I-infected T cell clones derived from the ocular fluid of patients with HTLV-I uveitis.

The present study was designed to investigate the in vitro effects of potential therapeutic agents on cytokine production by five HTVL-I-infected T cell clones (TCC) established from the ocular fluid of patients with HTLV-I uveitis. Each of the five HTLV-I-infected TCC was cultured at 1 x 10(6) cells/ml with or without an immunosuppressive agent (hydrocortisone, FK506, rapamycin, indomethacin, or prostaglandin E2) for 22 hr in humidified 5% CO2 in air at 37 C. The production of various cytokines in the culture supernatant from each TCC was measured by ELISA. The HTLV-I-infected TCC produced high amounts of IL-1 alpha, IL-3, IL-6, IL-8, TNF-alpha, IFN-gamma, and GM-CSF, and low but significant levels of IL-2 and IL-10 without any stimuli. Hydrocortisone severely depressed the production by these TCC of all the cytokines except for IL-2, which was slightly increased. Prostaglandin E2 depressed the production of IL-1 alpha, while it up-regulated the production of IL-6, TNF-alpha, and IFN-gamma. Rapamycin depressed the production of IL-6 and TNF-alpha, and FK506 depressed the production of TNF-alpha. Hydrocortisone also severely depressed the cytokine production by PHA-stimulated peripheral blood mononuclear cells obtained from healthy volunteers. Of the immunosuppressive agents tested, hydrocortisone exhibited the strongest suppression of cytokine production by HTLV-I-infected TCC. This result was in agreement with the in vivo effects of hydrocortisone in patients with HTLV-I uveitis. These TCC will be useful in investigating the effects of potential therapeutic agents for HTLV-I uveitis in vitro.

Body Fluids↗
PubMed1996

Detection and identification of Yersinia pestis by polymerase chain reaction (PCR) using multiplex primers.

A PCR method for detection of Yersinia pestis-virulence determinants by the use of multiplex primers was developed. Four pairs of oligonucleotide primers were designed from each gene of three kinds of virulent plasmids and a chromosomal DNA; 60-Md plasmid-located gene (caf1)encoding Y.pestis-specific capsular antigen fraction 1, a Y.pestis-specific region of a yopM gene encoded on 42-Md virulent plasmid, a plasminogen activator gene (pla) encoded on Y.pestis-specific 7-Md plasmid and an invasin protein gene (inv) encoded on chromosomal DNA. This multiplex-primer system was specific for the detection of Y.pestis among pathogenic Yersinia species and other enterobacteriaceae having antigens common to Y.pestis. Since this method is simple and safe, it will be useful to identify and confirm Y.pestis in cases of emergency and for the surveillance of epidemics.

Adhesins, Bacterial↗
PubMed1996

Induction of MAGE genes in lymphoid cells by the demethylating agent 5-aza-2'-deoxycytidine.

MAGE genes encoding tumor antigens recognized by cytotoxic T lymphocytes are appropriate target molecules for specific immunotherapy of cancer. We have investigated whether the demethylating agent 5-aza-2'-deoxycytidine (DAC) induces MAGE-1, -2, -3, and -6 in normal and malignant lymphoid cells. DAC induced these MAGE genes in both PHA/interleukin-2 (IL-2)-activated T cells from healthy donors and MAGE-negative T and B cell leukemias in most cases. It also induced MAGE-1 in IL-2-dependent T cell clones and all MAGE genes tested in Epstein-Barr virus-transformed B cell lines. Expression of MAGE-1 protein in the cells was confirmed by western blot analysis with anti-MAGE-1 polyclonal antibody. Therefore, demethylation is a potent stimulus to induce MAGE genes in both normal and malignant lymphoid cells.

Amino Acid Sequence↗
PubMed1996

Production of IL-6 by T cells from the femoral head of patients with rapidly destructive coxopathy (RDC).

RDC is a syndrome with unknown etiology that causes rapid destruction of a hip joint. We have investigated the production of osteoclast-activating cytokines (IL-6, IL-1alpha and tumour necrosis factor-alpha (TNF-alpha)), interferon-gamma (IFN-gamma) and IL-8 by T cells in the affected joint. The level of IL-6 produced by the T cell lines (TCL) established from the femoral head was significantly higher than that from patients' or healthy donors' peripheral blood mononuclear cells (PBMC). IL-6 production by the TCL from synovial membrane or from patients' PBMC was also significantly higher than that from healthy donors' PBMC. IL-1alpha production by the TCL from the femoral head was significantly higher than any of the other groups when all the TCL were used for the analysis. TNF-alpha production was highest in the TCL from patients' PBMC. The levels of IFN-gamma or IL-8 were not significantly different among these four groups. The plasma levels of all these cytokines except for IFN-gamma, that was rather lower, in RDC patients were not significantly different from those in osteoarthrosis or trauma patients, or healthy donors. These results suggest that T cells at the affected femoral head, and also synovial membrane to some extent, are involved in bone resorption through the production of IL-6 and probably IL-1alpha in patients with RDC.

Aged↗
PubMed1996

Event-related potential correlates of functional hearing loss: reduced P3 amplitude with preserved N1 and N2 components in a unilateral case.

A female patient exhibiting functional hearing loss in her left ear demonstrated reduced amplitude of P3 component in event-related potentials (ERP) to left monaural stimulation, with preserved N1 and N2 components to stimulation of either ear. This result suggested that stimuli in the affected ear were conducted successfully up to the auditory cortex but that further processing in higher brain regions was 'repressed'. Event-related potential examination for such hysterical disorders could be useful in clarifying their brain mechanism and offer a useful diagnostic clue to its nature.

Adult↗
PubMed1996

[Rapid detection of the hemolysin genes in Aeromonas sobria by the polymerase chain reaction].

The hemolysin of Aeromonas sobria is one of the important virulence factors in this organism. Rapid detection and identification test for A. sobria is important for early and specific diagnosis of this infectious disease. We evaluated the polymerase chain reaction (PCR) for the rapid detection of A. sobria. Two pairs of synthetic oligonucleotide primers (ASA1-s and a; AerAAS-s and a) were used in PCR technique to detect the different hemolysin genes (ASA1 and aerAAS) in A. sobria. The PCR identified 91% of ASA1-positive and 23.4% of aerAAS-positive strains in beta-hemolytic A. sobria. Other species of Aeromonas, Plesiomonas shigelloides, Vibrio cholerae O1 and V. parahaemolyticus tested were negative in the PCR with two pairs of primers. The PCR technique for detection of two hemolysin genes suggested the possibility of application of this method for detection of A. sobria in A. sobria-associated infections.

Aeromonas↗
PubMed1996

[Characteristics of enterotoxigenic Escherichia coli and E. coli harboring enteroaggregative E. coli heat-stable enterotoxin-1 (EAST-1) gene isolated from a water-borne outbreak].

A water-borne outbreak occurred in A Town in Akita prefecture on March 1995. Enterotoxigenic Escherichia coli (ETEC) strains were isolated from 6 of 13 feces of patients with food poisoning disease and from 1 of 4 drinking water samples. In addition, E. coli strains harboring Enteroaggregative E. coli (EAggEC) heat-stable enterotoxin-1 (EAST-1) gene were isolated from 5 of 13 patient's feces and 1 feces sample obtained from the septic tank. Both of the E. coli strains were isolated from the 3 patient's feces, suggesting that this outbreak was a mixed infectious case. All of the ETEC strains possessed both heat-stable enterotoxin (ST) and EAST-1 genes and their serotype was O148:H28. The EAST-1 gene was detected on a ca. 80 kb plasmid by a southern blot analysis using EAST-1 DNA probe in the 5 of 7 ETEC strains. The southern blot analysis suggested that the location of the EAST-1 gene was genome in the rest of the 2 ETEC strains. A southern blot analysis using ST DNA probe also suggested that the location of the ST gene was genome in all of the ETEC strains. On the other hand, all of the 6 E. coli strains harboring EAST-1 gene could not be serotyped with commercially available OH sera. The location of the EAST-1 gene in all of the isolates was suggested to be genome by the southern blot analysis. All of the isolates lacked aggA gene which has been demonstrated to be involved in expression of aggregative adherence phenotype in EAggEC, suggesting that the EAST-1 gene-harboring strains isolated in this case were distinct from EAggEC. These results indicated that the EAST-1 gene was also harbored by E. coli strains distinct from EAggEC. In addition, a possibility was also suggested that the EAST-1 gene might be a transposon, as well as ST gene. Further study should be conducted in order to elucidate the significance of EAST-1 as a vilurence factor of diarrheagenic E. coli.

Bacterial Toxins↗
PubMed1996

Bach proteins belong to a novel family of BTB-basic leucine zipper transcription factors that interact with MafK and regulate transcription through the NF-E2 site.

Members of the small Maf family (MafK, MafF, and MafG) are basic region leucine zipper (bZip) proteins that can function as transcriptional activators or repressors. The dimer compositions of their DNA binding forms determine whether the small Maf family proteins activate or repress transcription. Using a yeast two-hybrid screen with a GAL4-MafK fusion protein, we have identified two novel bZip transcription factors, Bach1 and Bach2, as heterodimerization partners of MafK. In addition to a Cap'n'collar-type bZip domain, these Bach proteins possess a BTB domain which is a protein interaction motif; Bach1 and Bach2 show significant similarity to each other in these regions but are otherwise divergent. Whereas expression of Bach1 appears ubiquitous, that of Bach2 is restricted to monocytes and neuronal cells. Bach proteins bind in vitro to NF-E2 binding sites, recognition elements for the hematopoietic transcription factor NF-E2, by forming heterodimers with MafK. Furthermore, a DNA binding complex that contained MafK as well as Bach2 or a protein related closely to Bach2 was found to be present in mouse brain cells. Bach1 and Bach2 function as transcription repressors in transfection assays using fibroblast cells, but they function as a transcriptional activator and repressor, respectively, in cultured erythroid cells. The results suggest that members of the Bach family play important roles in coordinating transcription activation and repression by MafK.

Amino Acid Sequence↗
PubMed1996

Effect of 10% ethanol and sofalcone on prostaglandin E2 content, mucus gel thickness, and experimental ulcers in the stomach of developing rats.

We studied the effects of a mild irritant, 10% ethanol, and sofalcone on the gastric mucosal defense mechanisms in newborn rats, comparing the effects to those seen in adult rats. The results indicated (1) that both mucosal prostaglandin E2 (PGE2) content and mucus gel layer thickness increased with age, (2) that sofalcone, but not 10% ethanol, increased mucosal PGE2 content and mucus gel thickness in 1- and 8-week-old rats, (3) that both sofalcone and 10% ethanol decreased mucosal damage induced by 50 or 75% ethanol in both age groups, and (4) that 10% ethanol, but not sofalcone, decreased ethanol-induced mucosal damage in rats pretreated with indomethacin. We concluded that 10% ethanol and sofalcone increase gastric mucosal defence mechanisms in newborn rats as in older rats.

Aging↗
PubMed1996

Effects of a thromboxane synthase inhibitor (CS-518) on the eosinophil-dependent late asthmatic response and airway hyperresponsiveness in guinea pigs.

The effects of CS-518, a thromboxane A2 synthase inhibitor, on antigen-induced dual bronchial responses, airway hyperresponsiveness (AHR) and airway eosinophilia were investigated in an experimental guinea pig model of the late asthmatic response. Oral CS-518 (1 and 10 mg/kg) inhibited immediate and late asthmatic responses dose-dependently. It also inhibited AHR and eosinophil accumulation after antigen challenge. Therefore, thromboxane A2 is possibly involved in development of the late asthmatic response and AHR, and CS-518 was inferred to inhibit these via inhibition of eosinophil accumulation and thromboxane production.

Animals↗
PubMed1996

Relationship between airway eosinophilia and airway hyperresponsiveness in a late asthmatic model of guinea pigs.

To elucidate the mechanism of development of asthma, we tried to develop a model which elicited a late asthmatic response by a combination of systemic and inhaled sensitization with ovalbumin in guinea pigs. Eighty-seven percent of animals elicited both an immediate and late asthmatic response after the third antigen inhalation. Airway eosinophilia and airway hyperresponsiveness (AHR) induced after the third challenge were more severe than those after the first challenge. There was a good correlation between airway eosinophilia and AHR in this model under experimental modulation of the number of eosinophils, such as by interleukin 5 or antieosinophil antibody injection. These results demonstrate that eosinophils play an important role in the development of late asthmatic response and AHR.

Animals↗
PubMed1996

Testotoxicosis proved by immunohistochemical analysis and successfully treated with cyproterone acetate.

We present a case of testotoxicosis diagnosed on the basis of immunohistochemical investigation of the testis. The patient was treated with the antiandrogen cyproterone acetate at a dose of 70-130 mg/m2/day. Clinical and biochemical features are consistent with the diagnosis of testotoxicosis. The long-term experience with cyproterone acetate had been generally satisfactory. There are, to our knowledge, no reports on cyproterone acetate treatment of testotoxicosis.

Age Factors↗
PubMed1996

Preparation of a monoclonal antibody specific for 5-methyl-2'-deoxycytidine and its application for the detection of DNA methylation levels in human peripheral blood cells.

A monoclonal antibody specific for a modified nucleoside, 5-methyl-2'-deoxycytidine (m5dCyd), was prepared using 5-methylcytidine (m5Cyd)-keyhole limpet haemocyanin (KLH) conjugate, and was characterized. Termed FMC9, the antibody reacts with m5dCyd and slightly with m5Cyd and 5-methylcytosine (m5Cyt) but not with other nucleosides tested in this investigation. FMC-9 was used in an enzyme-linked immunosorbent assay (ELISA) system for the quantitation of m5dCyd levels. Sensitivity was in the picomole range. Methylation levels in peripheral blood cells of healthy donors were determined by inhibition ELISA. The percentage of m5dCyd in peripheral blood cells of 10 healthy donors was 5.08 +/- 0.50%. These results suggest that the inhibition ELISA using FMC9 is useful to monitor m5dCyd levels in the peripheral blood cells.

Adult↗