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Biomedical subjects

K Sugahara

Publications and source records attributed to K Sugahara.

At least 73 records · Page 4Linked to original sources
PubMed2000

Qualitative and quantitative characterization of Fas (CD95) expression and its role in primary human acute leukemia cells.

Fas antigen, a cell surface molecule, directly mediates apoptosis, and is expressed on a limited number of human tissues. Blood or bone marrow samples from patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL) and mixed leukemia were examined qualitatively and quantitatively for the expression of Fas as well as its function using flow cytometry and the annexin V staining method. Fas expression was flow cytometrically unimodal with heterogeneous density, and showed quantitatively characteristic features in different diseases: undetectable in mixed leukemia, faint to weak in ALL, low in M0 and M1, and variable (low to strong) in M2, M3, M4, and M5. Both the full-length and the alternatively spliced truncated mRNAs were detected constitutively even in acute leukemia cells with qualitatively negative and quantitatively faint Fas, and the band density of the former transcripts detected by RT-PCR was correlated with the level of expression of the Fas protein. Short-term culturing of freshly isolated leukemia cells gave rise to an increase of Fas density. In acute leukemia cells, the apoptosis induced by anti-Fas MoAb was compared with that induced by etoposide (a topoisomerase II inhibitor). We found that fresh ALL and AML cells were resistant to the anti-Fas IgM antibody, while etoposide could trigger apoptosis in all types of leukemia tested. The combined effects of the anti-Fas MoAb and etoposide were not always synergistic. These results suggest that Fas is a biological marker for characterizing ALL and AML cells, and provide insight into creating a new therapeutic modality using cytotoxic drugs and cytokines together with modulation of Fas.

Acute Disease↗
PubMed2000

Recent advances in the study of the biosynthesis and functions of sulfated glycosaminoglycans.

Recent cDNA cloning of the glycosyltransferases involved in the synthesis of the sulfated glycosaminoglycan sidechains of proteoglycans has provided important clues to answering long-standing questions concerning the mechanisms of both chain polymerization and the biosynthetic sorting of glucosaminoglycans (heparin/heparan sulfate) and galactosaminoglycans (chondroitin/dermatan sulfate). These biosynthetic mechanisms are crucial to the expression and regulation of the biological functions of glycosaminoglycans in development and pathophysiology.

Glycosaminoglycans↗
PubMed2000

Extracellular norepinephrine in the medial hypothalamus increases during feeding in chicks: a microdialysis study.

Norepinephrinergic function in the medial hypothalamus is important for the regulation of feeding behavior in chicks as well as in rats. This study was conducted to clarify the variation of extracellular norepinephrine (NE) in the medial hypothalamus, including the paraventricular nucleus (PVN) and the ventromedial hypothalamic nucleus (VMN), during feeding behavior of layer-type chicks. To measure extracellular NE and 4-hydroxy-3-methoxyphenylglycol (MHPG), a major metabolite of NE, we used microdialysis and high-pressure liquid chromatography (HPLC) with electrochemical detection. After the collection of baseline samples, food-deprived animals were allowed access to the food for 3 h. Extracellular NE significantly increased during the first hour of access to food, and then returned to baseline levels. MHPG also increased during the feeding, but its increase continued throughout the remainder of the experiment. This study suggests that the variation of NE in the medial hypothalamus may be involved in the control of feeding in layer-type chicks.

Animals↗
PubMed2000

Comparative effect of amrinone, aminophylline and diltiazem on rat airway smooth muscle.

We investigated the effect of amrinone, a phosphodiesterase III inhibitor, on rat airway smooth muscle, and thereafter, compared its activity with aminophylline and diltiazem. Amrinone produced relaxation of the acetylcholine-induced airway contraction in a dose-related manner. This bronchodilatory activity of amrinone was similar to that of aminophylline, but smaller than that of diltiazem. The 50% relaxant effect (ED50) of amrinone, aminophylline and diltiazem were 3.6 x 10(-4) M, 1.4 x 10(-4) M and 1.4 x 10(-5) M, respectively. Diltiazem was the most potent airway relaxant, and amrinone was less potent in these experiments. Taken together in its positive inotropic and chronotropic effects and anti-inflammatory activity, however, amrinone could be beneficial for treatment of patients suffering from asthma or heart failure with cardiac asthma.

Acetylcholine↗
PubMed2000

Lactacystin activates FLICE (caspase 8) protease and induces apoptosis in Fas-resistant adult T-cell leukemia cell lines.

Lactacystin (LC) is a specific inhibitor of the proteasome, and has recently been shown to induce apoptosis in certain cell lines. In the present study, we established Fas-resistant adult T-cell leukemia (ATL) cell subclones RSO4 and RST1 from their parental Fas-sensitive cell lines SO4 and ST1, and examined whether LC can overcome Fas resistance. LC completely inhibited proteasome function as determined by a peptidyl-MCA substrate (LLVY-MCA and LLE-MCA), and induced apoptosis in these cell lines irrespective of Fas sensitivity at low concentrations (approximately 10 microM). LC induced the activation of caspase 3 (CPP32/Yama) and caspase 6 proteases in an identical manner to Fas-mediated apoptosis. Moreover, LC induced the activation of caspase 8 (FLICE) protease, which is the initiator of the Fas-mediated apoptotic cascade. Synthesized proteasome inhibitory peptide MG-115 (ZLLnV-CHO) also induced apoptosis in these cell lines. These results indicated that proteasome inhibitors overcome Fas-resistance by bypassing the proximal part of the Fas signal. Inhibition of the proteasome function may be a new strategy for the treatment of ATL.

Acetylcysteine↗
PubMed2000

Accumulation of cystathionine, cystathionine ketimine, and perhydro-1,4-thiazepine-3,5-dicarboxylic acid in whole brain and various regions of the brain of D, L-propargylglycine-treated rats.

Experimental cystathioninuria was induced in rats by administration of the cystathionine gamma-lyase inhibitor, D,L-propargylglycine. The cystathionine metabolites, cystathionine ketimine (CK) and perhydro-1,4-thiazepine-3,5-dicarboxylic acid (PHTZDC), were identified in whole brain and various regions of the brain in D,L-propargylglycine-treated rats. The concentration of CK and PHTZDC in whole brain and various regions of the brain increased gradually after administration of D,L-propargylglycine, and reached the highest value at about 20 hours. CK and PHTZDC accumulated in whole brain and various regions of the brain in proportion to the amount of accumulated cystathionine after D,L-propargylglycine administration. The concentration of these compounds in the cerebellum was higher versus the other regions of the rat brain.

Alkynes↗
PubMed2000

Value of laparoscopic microwave coagulation therapy for hepatocellular carcinoma in relation to tumor size and location.

BACKGROUND AND STUDY AIMS: The indications for laparoscopic microwave coagulation therapy (LMCT) for hepatocellular carcinoma (HCC) have not yet been adequately evaluated. This study investigated the value of LMCT in the treatment of HCC. PATIENTS AND METHODS: Forty-three patients with liver cirrhosis (including five patients in Child Pugh grade C), with 56 HCC lesions, were enrolled in the study. When dynamic computed tomography (CT) showed a loss in HCC enhancement characteristics and a low concentration area after LMCT, a lesion was judged to have undergone complete necrosis. RESULTS: The rate of complete necrosis for lesions measuring 40 mm or less was significantly higher (P<0.01) than for those measuring 41 mm or more. The rate of complete necrosis for lesions located on the liver surface, excluding those located close to the gallbladder or in contact with the diaphragm, was also significantly higher (P<0.01) than for those situated deep within the liver. The outcome for lesions of 40 mm or less was favorable. Intra-abdominal hemorrhage occurred in two patients, pneumothorax in three, and hepatic infarction in one, all associated with LMCT. However, these patients did not suffer any sequelae of clinical significance. CONCLUSIONS: This study suggests that there is a strong indication for LMCT for HCCs measuring 40 mm or less in diameter and those located on the liver surface even if they are as large as 50 mm, but not for those located close to the gallbladder or in contact with the diaphragm. LMCT appears to be applicable in patients with impaired liver function.

Aged↗
PubMed2000

The EXT1/EXT2 tumor suppressors: catalytic activities and role in heparan sulfate biosynthesis.

The D-glucuronyltransferase and N-acetyl-D-glucosaminyltransferase reactions in heparan sulfate biosynthesis have been associated with two genes, EXT1 and EXT2, which are also implicated in the inherited bone disorder, multiple exostoses. Since the cell systems used to express recombinant EXT proteins synthesize endogenous heparan sulfate, and the EXT proteins tend to associate, it has not been possible to define the functional roles of the individual protein species. We therefore expressed EXT1 and EXT2 in yeast, which does not synthesize heparan sulfate. The recombinant EXT1 and EXT2 were both found to catalyze both glycosyltransferase reactions in vitro. Coexpression of the two proteins, but not mixing of separately expressed recombinant EXT1 and EXT2, yields hetero-oligomeric complexes in yeast and mammalian cells, with augmented glycosyltransferase activities. This stimulation does not depend on the membrane-bound state of the proteins.

Animals↗
PubMed2000

Retinoic acid accelerates the development of reproductive organs and egg production in Japanese quail (Coturnix coturnix japonica).

The effects of retinoic acid on the development of reproductive organs and egg production in female Japanese quail (Coturnix coturnix japonica) were investigated. Female quail were fed a diet containing retinoic acid at 4 mg/kg (RA) or two diets containing retinyl acetate at 5000 IU/kg (VA1) or 14 000 IU/kg (VA2) after being fed a vitamin A-free diet for 2 wk (experiment 1). The oviduct and ovary grew more rapidly (P < 0.05) in RA-treated quail than in VA-treated quail at 5 wk of age. In addition, the body weight of RA-fed quail was also greater (P: < 0.05) than that of VA-fed quail at 5 wk. The RA-treated quail laid their first eggs approximately 5 days earlier (P < 0.05) than the VA-treated quail. Furthermore, these RA-fed quail laid more eggs (P < 0.05) than those VA-fed quail during the experimental period. To confirm the results of experiment 1, a similar experiment was conducted to record the first egg and total eggs laid by quail fed VA2 or RA (experiment 2). The early onset of oviposition was again observed in the RA-treated group (P < 0.01). These results suggest that retinoic acid has a stimulating effect on the reproductive system of female Japanese quail, as has been previously shown in the reproductive system of male Japanese quail.

Animals↗
PubMed2000

The tyrosine kinase activity of the chicken insulin receptor is similar to that of the human insulin receptor.

The tyrosine kinase activity of a chimeric insulin receptor composed of the extracellular domain of the human insulin receptor (IR) and the intracellular domain of the chicken IR was compared with wild-type human IR. The degrees of autophosphorylation, phosphorylation of IRS-1, and in vitro phosphorylation of an exogenous substrate after stimulation by human insulin were similar to that seen with the human IR. We conclude that the insulin resistance of chickens is not attributable to a lower level of intrinsic tyrosine kinase activity of IR.

3T3 Cells↗
PubMed2000

[Characteristics of plasma DNA and its application for detection of K-ras gene mutation].

DNA diagnosis is useful and significant for clinical oncology, but its use is limited due to a difficulty in preparing tumor-derived DNA materials. To overcome this problem, we investigated the characterization of plasma DNA and it application to successfully detecting K-ras mutation at codon 12 in normal persons, hematopoietic neoplasms, and solid tumors. The range of plasma DNA in each group was 15.8 +/- 5.2 ng/ml, 43.3 +/- 29.8 ng/ml, and 26.8 +/- 17.0 ng/ml, respectively. The ranges in patients with solid tumor were gradually decreased to the normal level of around 15 ng/ml in 3 weeks postoperatively. Plasma DNAs consisted of about 200 bp DNA fragmentation and were convenient for PCR amplification of K-ras gene. The mutation at codon 12 by PCR-RFLP analysis was detected in 13(27%) of 49 patients with solid tumors such as pancreatic cancer, breast cancer, colon cancer, and gastric cancer. The diagnostic specificity was 100%. Serial observations by the PCR-RFLP analysis revealed disappearance of the mutant K-ras about 7 days after successful curative surgery in a patient with gastric cancer.

Adult↗
PubMed2000

Real-time polymerase chain reaction for quantification of HTLV-1 proviral load: application for analyzing aberrant integration of the proviral DNA in adult T-cell leukemia.

We describe the establishment of a real-time polymerase chain reaction (PCR) assay for the quantitative estimation of human T-cell leukemia virus type 1 (HTLV-1) proviral load using a LightCycler Technology (Roche Diagnostics, Mannheim, Germany) instrument. Proviral DNA level represents a measure of the integrated viral genome in host cells, so we applied this technique to evaluate the tumor burden in adult T-cell leukemia (ATL) patients with aberrant integration patterns of HTLV-1 detected by standard Southern blot hybridization (SBH) analysis. In 14 of our 15 ATL cases with 2 or more bands detected by SBH analysis, the ATL cells were shown to harbor multiple copies of the provirus within 1 ATL cell. This result suggests the usefulness of real-time PCR quantification for the study of the relationship between ATL pathology and HTLV-1-induced pathogenesis.

DNA, Viral↗
PubMed2000

[Southern blot hybridization analysis for lymphoid neoplasms].

The recent remarkable progress of molecular biology gave us new tools for examination of the etiology and pathology of many diseases. Hence, the introduction of such techniques in our clinical laboratory area is becoming more important and indispensable year by year. In addition to morphological and phenotypical analysis, we are now establishing a molecular diagnosis system to support the clinical diagnosis of hematological malignancies. In the present study, we show our ongoing results focusing on adult T-cell leukemia(ATL). Southern blot analysis for detection of the monoclonal integration of HTLV-I proviral genome, a causative agent of ATL, was performed using digoxigenin-labeled probe. The sensitivity was equivalent to RI-labeled probe and was enough for clinical use. We are also doing Southern blot analysis for immunoglobulin heavy chain gene and T-cell receptor beta chain gene as custom service for the diagnosis of B-lymphoproliferative disorders and non-ATL T-lymphoproliferative disorders. We are reporting such results to the clinical site with our interpretation. Since the band size of the HTLV-I provirus obtained by Southern blot differed in each case and was sometimes smaller than the size of the complete virus, we further analyzed the structure of HTLV-I using long and accurate PCR(LA-PCR) and sequence-target-site PCR(STS-PCR). We found that the integrated HTLV-I provirus is divided into two subtypes, complete virus and defective virus. The incidence of defective virus was high in acute-type ATL compared with that in chronic- or lymphoma-type ATL. Although there are several difficulties in introducing such molecular analyses into the clinical laboratory area, we think that the need is increasing together with the progression of gene therapy and evidence-based medicine.

Blotting, Southern↗
PubMed2000

Effect of cisplatin treatment on the urinary excretion of guanidinoacetic acid, creatinine and creatine in patients with urinary tract neoplasm, and on superoxide generation in human neutrophils.

Production of guanidinoacetic acid, a precursor of creatinine is known to be reduced by metabolic disturbance when kidney function is damaged, and thus it may be a sensitive marker of renal damage. Therefore, the urinary levels of guanidinoacetic acid, creatinine and creatine from patients with urinary tract neoplasm who received cisplatin treatment were measured by liquid chromatography-mass spectrometry. Following the administration of cisplatin, the urinary excretion of guanidinoacetic acid decreased significantly, and the low concentration was maintained for at least five days. The concentrations of creatinine and creatine gradually decreased until the third day after cisplatin administration, and slightly increased on the fifth day. As superoxide might be concerned in renal damage by cisplatin, the effect of cisplatin on superoxide generation was also investigated using human neutrophils. Cisplatin significantly enhanced phorbol 12-myristate 13-acetate-induced superoxide generation in a concentration-dependent manner, but had no effect on the superoxide generation induced by N-formyl-methionyl-leucyl-phenylalanine and arachidonic acid. The superoxide generation increased by cisplatin was inhibited by staurosporine, an inhibitor of protein kinase C, but was rather enhanced by genistein, an inhibitor of protein tyrosine kinase.

Adult↗
PubMed1999

Simultaneous determination of N-acetylaspartic acid, N-acetylglutamic acid, and N-acetylaspartylglutamic acid in whole brain of 3-mercaptopropionic acid-treated rats using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

The measurement of N-acetylaspartic acid (NAA), N-acetylglutamic acid (NAG), and N-acetylaspartylglutamic acid (NAAG) in the whole brain of 3-mercaptopropionic acid (3-MPA)-treated rats has been developed using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system. The recoveries of these compounds were 90.85 +/- 3.43% for NAA, 91.62 +/- 5.47% for NAG, and 92.29 +/- 4.44% for NAAG. The detection limits for NAA, NAG, and NAAG were 12, 15, and 20 microg/ml, respectively. After administration of 3-MPA, the concentrations of NAA, NAG, and NAAG in the whole brain over 10 min increased 177.25, 134.23, and 127.70%, respectively. These concentrations then decreased over the next 60 min. The simultaneous determination of NAA, NAG, and NAAG using this method was found to be very useful for studies of metabolism of NAA, NAG, and NAAG in biological samples.

3-Mercaptopropionic Acid↗
PubMed1999

Fas-resistance in ATL cell lines not associated with HTLV-I or FAP-1 production.

A preventive role for human T-cell leukemia virus type-I (HTLV-I) and Fas-associated phosphatase-1 (FAP-1) in Fas-mediated apoptosis has been reported in HTLV-I-infected cells. In the present study, we examined whether these molecules increased during the acquisition of Fas-resistance in adult T-cell leukemia (ATL) cell lines. SO4, ST1 and KK1 are Fas-sensitive ATL cell lines, and produce small amounts of HTLV-I in vitro. Although their subclones RSO4 and RST1 are completely Fas-resistant, they produced an equivalent amount of HTLV-I to SO4 and ST1. Moreover, FAP-1 mRNA was not detected in these cell lines irrespective of Fas sensitivity. Thus, Fas resistance in ATL cells was not directly associated with the increased production of HTLV-I or FAP-1.

Antibodies, Monoclonal↗