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Biomedical subjects

K Sugimura

Publications and source records attributed to K Sugimura.

At least 181 records · Page 10Linked to original sources
PubMed1992

[Low flip angle spin-echo MR imaging to obtain better Gd-DTPA enhanced imaging with ECG gating].

ECG-gated spin-echo imaging (ECG-SE) can reduce physiological motion artifacts. However, ECG-SE does not provide strong T1-weighted images because repetition time (TR) depends on heart rate (HR). We investigated the usefulness of low flip angle spin-echo imaging (LFSE) in obtaining more T1-dependent contrast with ECG gating. in computer simulation, the predicted image contrast and signal-to-noise ratio (SNR) obtained for each flip angle (0-180 degrees) and each TR (300 msec-1200 msec) were compared with those obtained by conventional T1-weighted spin-echo imaging (CSE: TR = 500 msec, TE = 20 msec). In clinical evaluation, tissue contrast [contrast index (CI): (SI of lesion-SI of muscle)2*100/SI of muscle] obtained by CSE and LFSE were compared in 17 patients. At a TR of 1,000 msec, T1-dependent contrast increased with decreasing flip angle and that at 38 degrees was identical to that with T1-weighted spin-echo. SNR increased with the flip angle until 100 degrees, and that at 53 degrees was identical to that with T1-weighted spin-echo. CI on LFSE (74.0 +/- 52.0) was significantly higher than CI on CSE (40.9 +/- 35.9). ECG-gated LFSE imaging provides better T1-dependent contrast than conventional ECG-SE. This method was especially useful for Gd-DTPA enhanced MR imaging.

Contrast Media↗
PubMed1992

Search for MHC-associated genes in human: five new genes centromeric to HLA-DP with yet unknown functions.

Taking advantage of five mouse genomic or cDNA probes [KE5(probe 14), KE4 (probe 11), KE3 (probe 7), KE2 (probe 5), and SET] mapped on the H-2K region in mouse, we have identified and localized homologues of these five genes in the human major histocompatibility complex region (HKE5, HKE4, HKE3, HKE2, and HSET, respectively). Cosmid cloning and pulsed field gel electrophoresis analyses indicated that a human homologous gene, HKE5, is located 10 kilobases (kb) centromeric of the alpha 2 (XI) collagen (COL11A2) gene followed by HKE4. HKE3, closely linked to HKE2, is located 170 kb centromeric of HKE4. Furthermore, HSET is located 50 kb centromeric of HKE2. This gene organization outside the DP subregion is completely identical to that of the mouse H-2K region centromeric of I-Pb3, a mouse homologue of the DPB gene, except the lack of genes corresponding to the H-2K and -K2 genes in human.

Blotting, Southern↗
PubMed1992

Magnetic resonance imaging of uterine leiomyosarcoma.

The magnetic resonance imaging (MRI) findings in a patient with uterine leiomyosarcoma are reported. MRI provides higher contrast resolution in soft tissues than ultrasonography or CT, and the MRI findings described in this case report suggest that MRI can be used to help differentiate between leiomyosarcoma from myoma.

Female↗
PubMed1992

Argininosuccinate synthetase gene expression in leukemias: potential diagnostic marker for blastic crisis of chronic myelocytic leukemia.

Argininosuccinate synthetase (ASS) activity is hardly detected in human lymphocytes. In this study, we examined the ASS gene expression of various leukemia cells by a polymerase-chain-reaction method. We demonstrate here that (a) acute lymphocytic and acute myelocytic leukemia cells exhibit the highly elevated expression of the ASS gene and (b) chronic myelocytic leukemia (CML) in blastic crisis also exhibits the increase of ASS gene expression while CML in chronic phase, chronic lymphocytic leukemia and adult T leukemia cells show the similar level to that of normal lymphocytes. These results suggest that the ASS gene expression is of value as a diagnostic marker of acute type leukemia, particularly for blastic crisis of CML.

Adult↗
PubMed1992

Tongue cancer treated with irradiation: assessment with MR imaging.

We examined the usefulness of MRI in differentiating post-radiation scar tissue from the residual tumour. Ten consecutive patients who underwent MR imaging before and after radiation therapy were assessed prospectively. T1- and T2-weighted images using a 1.5 unit were obtained in 10 patients (3 T1, 6 T2, 1 T3) at 1 week before irradiation, and 2 weeks, 2 months, 4 months, 6 months and every 6 months thereafter following completion of radiation. Although all T2 and T3 tumours demonstrated high signal intensity compared to muscle on T2-weighted images, the T1 tumour could be demonstrated in only one of three patients. Six patients in whom the primary tumour clinically disappeared demonstrated low signal intensity on T2-weighted images until 4 months after completion of radiation therapy (range 1 week to 4 months). This study suggests that MRI can detect primary tumours larger than T2 (2 cm), and may be useful in assessing the effectiveness of therapy for tongue cancer.

Adult↗
PubMed1992

Detection and staging of prostatic carcinoma after transurethral resection or open enucleation of the prostate: accuracy of magnetic resonance imaging.

A total of 17 patients who had undergone transurethral (16) or open (1) enucleation of the prostate for presumed benign prostatic hyperplasia had prostatic adenocarcinoma: 10 on the basis of examination of the resected specimen (stage A) and 7 upon rectal examination performed 2 to 120 months after prostatectomy for benign prostatic hyperplasia (stage B). In all patients magnetic resonance imaging (MRI) of the prostate was performed before radical retropubic prostatectomy. Preoperative imaging was compared to pathological findings with respect to the presence, location and stage of singular or multiple prostatic carcinomas. Carcinomas were categorized according to the location within the prostate: whether on the right or left side, and whether in the peripheral zone (anterior, anterolateral or posterior) or the transition zone. The sensitivity of tumor detection for cancers originating in the peripheral zone was 81%. However, the sensitivity of detection decreased to 0% for tumors confined to the transition zone. Tumor staging was not compromised by previous prostatic enucleation or transurethral resection. MRI correctly identifies carcinomas originating in the peripheral zone but cannot detect those confined to the transition zone.

Adenocarcinoma↗
PubMed1992

High sensitivity of human melanoma cell lines to the growth inhibitory activity of mycoplasmal arginine deiminase in vitro.

Arginine deiminase (AD) is a potent growth inhibitor for some but not all tumour cell lines in vitro. As AD catalyses the direct conversion of L-arginine to L-citrulline, the AD-sensitivity of various tumour cells might be attributed to the levels of urea cycle enzymes involved in L-arginine biosynthesis. This study demonstrated that human melanoma cells were highly sensitive to the growth inhibitory activity of AD. Five melanoma cell lines tested also exhibited reduced argininosuccinate synthetase (ASS) gene expression--being almost absent in four cell lines and at low level in one cell line. This resulted in an inability of the cells to utilize L-citrulline for growth. Based on the tissue-specific regulation of ASS gene, the feature of melanomas suggests that it might be possible to develop agents with strong AD activity for chemotherapeutic use for human melanomas in vivo.

Antineoplastic Agents↗
PubMed1992

Arginine deiminase gene of an AIDS-associated mycoplasma, Mycoplasma incognitus.

Recently, we have demonstrated by molecular cloning that a strong immunosuppressive factor derived from Mycoplasma arginini is arginine deiminase. We show here that mycoplasma species identified in many of AIDS patients also bear the arginine deiminase gene. The implication of the arginine deiminase gene detected in AIDS-associated mycoplasma species is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Association of HLA-B51 and lack of association of class II alleles with Behçet's disease.

Eighty-one Behcet's disease patients have been studied for HLA association by HLA-DRB1, -DQA1, -DQB1 and -DPB1 genotyping with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique and for NcoI RFLP in the tumor-necrosis factor (TNF beta) gene by Southern hybridization in addition to serological typing. In serological typing, the frequency of HLA-B51 was significantly increased in the patients. In PCR genotyping, there was a significant increase in the HLA-DRB1*0802, DQA1*0301 and DQB1*0303 alleles, whereas the frequencies of DRB1*1502, DQA1*0103, DQA1*0101, DQB1*0601 and DQB1*0501 showed a significant decrease in the patients. No significant difference was observed in any HLA-DPB1 alleles. Among them, B51 was found to be a genetic marker most strongly associated with Behcet's disease (p less than 0.00005, chi 2 = 46.47, pc[corrected p] less than 0.005). The positive and negative associations of class II alleles with the disease can be explained by linkage disequilibrium with B51, and do not reach statistical significance by the corrected p-value test. In NcoI RFLP typing in the TNF beta gene, 250 kb centromeric of the HLA-B gene, the frequency of a 5.5 kb fragment was considerably decreased in the patients when compared to the controls, although the decrease was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1992

Reconstitution and partial purification of calcium transport activity from rat kidney cortex.

An ATP-dependent Ca2+ uptake system from rat renal cortical basolateral membranes was solubilized with Triton X-100 and reconstituted into liposomes with lecithin. In the presence of Mg2+, Ca2+ uptake in the reconstituted vesicles was time and ATP dependent and was inhibited by vanadate. Ca2+ uptake in basolateral membrane vesicles depleted of endogenous calmodulin was enhanced by exogenous calmodulin and depressed by R-24571. This sensitivity to calmodulin and R-24571 was lost upon reconstitution in the presence and absence of leupeptin. Vesicles containing Ca2+ uptake activity were separated by gradient centrifugation after Ca2+ was taken up and accumulated as calcium phosphate in the vesicles. This resulted in Ca2+ uptake activity that was enriched 25 times. However, Ca(2+)-dependent adenosinetriphosphatase (ATPase) activity was not enriched significantly. This Ca(2+)-ATPase had two kinetic forms for Ca2+: one was a high-affinity low-capacity form; the other had a low affinity and high capacity. The Ca(2+)-ATPase activity also had two kinetic forms for ATP. All kinetic forms were inhibited by Mg2+. Vanadate, calmodulin, and R-24571 had no effects on Ca(2+)-ATPase activity. A protein doublet of Ca(2+)-dependent hydroxylamine-sensitive phosphorylated intermediates was demonstrated at 125 and 136 kDa in the purified vesicles. This doublet was not altered by addition of leupeptin throughout the purification.

Adenosine Triphosphate↗
PubMed1992

The value of magnetic resonance relaxation time in staging ovarian endometrial cysts.

We evaluated the use of magnetic resonance imaging (MRI) in the pre-operative staging of 15 endometrial cysts. The effect of the iron content on the T1 and T2 relaxation times was assessed in confirmed endometrial cysts employing a 0.15 T MR system and a 200 MHz spectrometer. There was a positive linear correlation (r = 0.93) between the T1 values of the lesions obtained using the MR system (T1) and those of the resected cyst contents obtained using the spectrometer (sp-T1). A similar relationship was found between T2 and sp-T2 (r = 0.87). There was a negative linear relationship between the T1 value and the cyst iron content (r = -0.81), but there was no relationship between the T2 value and the iron content. T1 was 412 +/- 91 ms for Stage II cysts (n = 3), 356 +/- 126 ms for Stage III cysts (n = 3) and 208 +/- 30 ms for Stage IV cysts (n = 9). The T1 value for Stage IV cysts was significantly shorter than that for Stages II and III cysts (p less than 0.05). Thus, the T1 value was useful in distinguishing fresh from old endometrial cysts, suggesting that the MRI T1 relaxation time might be useful for staging ovarian endometrial cysts before surgery.

Endometriosis↗
PubMed1992

Elevated gene expression of argininosuccinate synthetase in peripheral lymphocytes from systemic lupus erythematosus (SLE) patients.

Argininosuccinate synthetase (ASS) is a rate-limiting enzyme of urea cycle and functions primarily in the liver, whereas ASS activity is hardly detected in normal lymphocytes. In this study, we examined the level of ASS gene expression in peripheral blood lymphocytes (PBL) from human SLE patients by amplification of reverse-transcribed mRNA using the polymerase chain reaction. We have demonstrated that (a) approximately 40% of SLE patients exhibited 2.5 to 5 times higher expression of ASS gene in PBL than those of healthy PBL and (b) the elevation of ASS gene expression of PBL significantly correlates with the active pathogenesis of SLE patients according to the criteria of Japanese Ministry of Health and Welfare (p < 0.001 by student's two-tailed t-test). Thus, it is suggested that ASS gene expression is a promising marker of hyperactivated lymphocytes uniquely generated in patients with systemic autoimmune disease.

Animals↗
PubMed1992

Stimulation of amino acid efflux from cells by extracellular serine.

P388 (murine) and CEM (human) leukemia cells were exposed in vitro to a serine-deprived medium. Cultivation was carried out at 37 degrees C, 5% CO2. Proliferation assay was conducted with a RPMI 1640 medium (control) and a serine-deprived medium for 3 days. The deprivation of serine reduced the proliferation of both cells, and the necessity of serine for the cell proliferation was thus recognized. The effects of the substance on the level and pattern of intracellular amino acids were observed. P388 cells exposed to serine-deprived medium for 3 h were then transferred to the control medium. The cellular amino acid levels were determined at the time of medium change and 1, 2, 3 h thereafter. Serine-deprivation improved intracellular amino acids in comparison with those from control, and the medium change to control reduced their levels. Therefore, extracellular serine appeared to regulate the efflux of amino acids from cells. This suggests that serine-deprivation may be useful for anticancer drug retention in the cells.

Amino Acids↗
PubMed1992

RFLP analysis in the TNF-beta gene and the susceptibility to alloreactive NK cells in Behçet's disease.

Behçet's disease is known to be associated with HLA-B51. To address the possibility that a non-human leukocyte antigen (HLA) gene closely linked to the HLA-B gene, such as tumor necrosis factor (TNF)-alpha, TNF-beta, or ECl (the locus that determines the susceptibility to alloreactive natural killer [NK] cells), is involved in the susceptibility to Behçet's disease, NcoI and EcoRI restriction fragment length polymorphisms in the TNF-beta gene and the susceptibility to lysis by alloreactive NK cells were investigated in Behçet's patients. In our NcoI restriction fragment length polymorphism (RFLP) analysis in the TNF-beta gene, the frequency of the NcoI 5.5 kb homozygote was decreased considerably in the patients, especially those with the ocular lesions, in relation to the healthy controls. However, no significant difference was observed between these groups in the EcoRI RFLP band distribution in this gene or the in susceptibility to lysis by alloreactive NK cells. These results indicated that a non-HLA gene located around the TNF gene region centromic of the HLA-B gene was a candidate to control the genetic susceptibility to Behçet's disease.

Base Sequence↗