Search PubMed⌕ Search

Biomedical subjects

N Harada

Publications and source records attributed to N Harada.

At least 271 records · Page 15Linked to original sources
PubMed1997

Rebamipide attenuates indomethacin-induced gastric mucosal lesion formation by inhibiting activation of leukocytes in rats.

Granulocyte elastase released from activated leukocytes plays an important role in leukocyte infiltration. Since activated leukocytes have been shown to be involved in the pathogenesis of gastric mucosal lesion formation induced by nonsteroidal antiinflammatory drugs, inhibition of granulocyte elastase release from activated leukocytes may be useful in the prevention of these lesions. Rebamipide, a novel antiulcer agent, inhibited granulocyte elastase release from activated neutrophils in vitro. Rebamipide and ONO-5046, a granulocyte elastase inhibitor, markedly inhibited gastric mucosal lesion formation in rats. Gastric myeloperoxidase activity was significantly increased 3 hr after indomethacin administration. This increase was significantly inhibited by rebamipide and ONO-5046. Cimetidine did not inhibit granulocyte elastase release from activated neutrophils. Although cimetidine markedly prevented the indomethacin-induced gastric mucosal lesion formation, it did not reduce the gastric myeloperoxidase activity. Therefore, unlike cimetidine, rebamipide may prevent indomethacin-induced gastric mucosal lesion formation by inhibiting neutrophil activation.

Alanine↗
PubMed1997

Nuclear accumulation of p53 correlates significantly with clinical features and inversely with the expression of the cyclin-dependent kinase inhibitor p21(WAF1/CIP1) in pancreatic cancer.

Recent studies have suggested a p53-independent expression of p21(WAF1/CIP1). We investigated the correlation between p53 overexpression and the expression of p21(WAF1/CIP1) in 57 patients with pancreatic adenocarcinoma. By means of reverse transcription and polymerase chain reaction (RT-PCR), we examined the mRNA levels of WAF1/CIP1 and compared them with the p53 status in 20 patients and in a further six pancreatic tumour cell lines. In pancreatic cancer tissues, immunohistological evaluation revealed a significant correlation between active p53 and p21(WAF1/CIP1) (P < 0.005) as well as WAF1/CIP1 mRNA expression (P < 0.005). This coherence was also evident in human pancreatic carcinoma cell lines. The analysis of p53 and p21(WAF1/CIP1) expression in relation to clinicopathological features revealed a significant correlation between p53 overexpression and tumour stage, tumour size, grading and lymph node metastases, whereas p21(WAF1/CIP1) expression correlated only with tumour size. We conclude that the expression of p21(WAF1/CIP1) normally depends on active p53, but that there may also exist p53-independent pathways of induction that reduce the correlation of p21(WAF1/CIP1) to clinicopathological features.

Adult↗
PubMed1997

Increased incidence of cytomegalovirus (CMV) infection and CMV-associated disease after allogeneic bone marrow transplantation from unrelated donors. The Fukuoka Bone Marrow Transplantation Group.

Cytomegalovirus (CMV) infection and CMV-associated disease were monitored using the CMV antigenemia assay in 72 patients who received allogeneic bone marrow transplantation (BMT), and their incidences were compared between related and unrelated donor transplant patients. The incidence of CMV infection after BMT was significantly higher in patients who received transplants from HLA-matched unrelated donors than from HLA-matched sibling donors (87% vs 53%, P < 0.05). CMV-associated disease developed in 73% of unrelated and in 14% of sibling donor transplant patients (P < 0.01). The peak levels of CMV antigenemia were significantly higher in unrelated donors than in sibling donor transplant patients (16 vs 1 CMV antigen-positive cells per 50000 WBCs, P < 0.01). The median number of CMV antigen-positive cells on first detection was also significantly higher in unrelated donor transplant patients (15 vs 1, P < 0.01). The detection of CMV antigen-positive cells preceded the development of CMV-associated disease in 18% of unrelated donor transplant patients, suggesting a lower predictive value of CMV antigenemia for subsequent CMV-associated disease in unrelated donor BMT. Careful monitoring and further studies are needed for the early diagnosis and prevention of CMV-associated disease in unrelated donor BMT.

Adolescent↗
PubMed1997

Autologous peripheral blood stem cell transplantation for acute myelogenous leukemia.

The safety and efficacy of myeloablative therapy followed by autologous peripheral blood stem cell transplantation (ABSCT) for acute myelogenous leukemia (AML) were evaluated in 60 patients. Peripheral blood stem cells (PBSC) were collected during recovery after consolidation chemotherapy. High-dose chemotherapy consisting of busulfan (16 mg/kg), etoposide (40 mg/kg), and cytosine arabinoside (3 g/m2 x 4) (BEA regimen) was used for pretransplant conditioning in 13 patients. For the remaining 47 patients, granulocyte colony-stimulating factor (G-CSF) was administered concurrently with the BEA regimen during conditioning. Unpurged, cryopreserved PBSC containing a median number of 5.4 x 10(8) MNC/kg or 12 x 10(4) CFU-GM/kg were reinfused at transplantation. The median number of days to granulocytes exceeding 500/microl and last platelet transfusion were 15 (8-44) and 24 (0->180), respectively. The 3-year probabilities of disease-free survival (DFS) and relapse were 78.6 and 21.4% for patients transplanted in first remission, 29.6 and 64.4% for those in second or third remission, and 11.1 and 77.8% for those in relapse, respectively. There were no transplant-related deaths within 100 days of transplantation. Age, disease status at transplantation, and number of induction chemotherapies to first complete remission were risk factors affecting the outcome of ABSCT. These results of ABSCT for AML in first remission warrant a prospective study of ABSCT as post-remission therapy.

Acute Disease↗
PubMed1997

Improvement of thermal stability of Streptomyces cholesterol oxidase by random mutagenesis and a structural interpretation.

Random mutagenesis was used to enhance the thermal stability of Streptomyces cholesterol oxidase. Four thermostable mutants were isolated and the following amino acid substitutions were identified: Ser103 to Thr (mutant S103T), Val121 to Ala (mutant V121A), Arg135 to His (mutant R135H) and Val145 to Glu (mutant V145E). The wild-type and mutant enzymes were purified and characterized. The properties of mutants S103T, V121A and R135H were similar to those of the wild type but they showed improved thermal stability. When the V145E mutation was introduced, the thermal stability of the enzyme was markedly increased and the optimum pH was desirably changed to encompass a broad range from acid to alkali. Analysis of multiple mutants constructed by site-directed mutagenesis showed that all the mutations except that of R135H had an additive influence on the other mutations. These mutational effects are discussed in terms of a three-dimensional structural model of the enzyme constructed on the basis of homology modelling.

Cholesterol↗
PubMed1997

Effects of green tea catechins (Polyphenon 100) on cerulein-induced acute pancreatitis in rats.

Effects of green tea catechins (GTC) on cerulein-induced acute pancreatitis in rats were examined. The acute pancreatitis induced by cerulein (cerulein pancreatitis) was characterized by interstitial edema and vacuolation. When cerulein pancreatitis was induced, prior administration of 0.1% GTC in drinking water for 1 week before the induction significantly decreased the wet weight of the pancreas, the serum level of amylase, and the tissue concentration of lipid peroxides in the pancreas compared with those in nonmedicated rats supplied with plain tap water only. Furthermore, the pancreatic tissue alterations of the medicated rats were milder than those of the nonmedicated rats. These data suggest that GTC have a protective effect on the pathogenesis of cerulein pancreatitis.

Acute Disease↗
PubMed1997

Effect of green tea catechins on the amount of 8-hydroxydeoxyguanosine (8-OHdG) in pancreatic and hepatic DNA after a single administration of N-nitrosobis(2-oxopropyl)amine (BOP).

Effects of green tea catechins on N-nitrosobis(2-oxopropyl)amine (BOP)-induced oxidative stress in pancreas and liver were examined. Hamsters were divided into two groups: one group was given free access to a 0.1% solution of green tea catechins as drinking water (c-ham) and the other to plain tap water (w-ham) for 1 week before subcutaneous injection of BOP 20 mg/kg body weight. Zero, 1, 2, 6, 12, 24, and 48 h after BOP injection, the pancreas and liver were excised and the tissue concentration of lipid peroxides (TBA values) and the amount of 8-hydroxydeoxyguanosine (8-OHdG) in nuclear DNA were measured. The concentration of lipid peroxides and the amount of 8-OHdG in the pancreas showed similar patterns of change between c- and w-ham. Soon after BOP injection, the concentration of lipid peroxides and the amount of 8-OHdG increased with a peak at 1 and 6 h, respectively. Their peak values of c-ham were significantly depressed compared with those of w-ham. Both levels returned to steady-state levels by 24 h. In the liver, the concentration of lipid peroxides and the amount of 8-OHdG were not affected by BOP administration. These results suggest that BOP induces oxidative damages in the target organ and oral intake of green tea catechins has a protective effect on the oxidative stress.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1997

Automatic extraction and measurement of leukocyte motion in microvessels using spatiotemporal image analysis.

This paper describes a computer vision system for the automatic extraction and velocity measurement of moving leukocytes that adhere to microvessel walls from a sequence of images. The motion of these leukocytes can be visualized as motion along the wall contours. We use the constraint that the leukocytes move along the vessel wall contours to generate a spatiotemporal image, and the leukocyte motion is then extracted using the methods of spatiotemporal image analysis. The generated spatiotemporal image is processed by a special-purpose orientation-selective filter and a subsequent grouping process newly developed for this application. The orientation-selective filter is designed by considering the particular properties of the spatiotemporal image in this application in order to enhance only the traces of leukocytes. In the subsequent grouping process, leukocyte trace segments are selected and grouped among all the segments obtained by simple thresholding and skeletonizing operations. We show experimentally that the proposed method can stably extract leukocyte motion.

Algorithms↗
PubMed1997

Synthesis and antitumor activity of 9-acyloxyellipticines.

Various kinds of water-soluble 9-acyloxyellipticine derivatives were synthesized in a search for compounds with potent antitumor activity. Antitumor activities against several tumors in mice (P388 leukemia, colon 26, Lewis lung carcinoma and B16 melanoma) were evaluated by using intravenous administration. Many compounds exhibited good antitumor activities; in particular, the glutarate derivative (5o) showed potent antitumor activity. This compound (5o) may be converted to 9-hydroxyellipticine (2) by enzyme-catalyzed hydrolysis in the body.

Animals↗
PubMed1997

Synthesis and antitumor activity of quaternary salts of 2-(2'-oxoalkoxy)-9-hydroxyellipticines.

Various kinds of water-soluble quaternary salts of 2-(2'-oxoalkoxy)-9-hydroxyellipticines were synthesized in a search for compounds with potent antitumor activity and low toxicity. Some compounds exhibited more potent antitumor activities than elliptinium (1) and SUN 4599 (3). In particular, 2-(3'-methoxy-2'-oxopropanoxy)-9- hydroxy-5,11-dimethyl-6H-pyrido[4,3-b]carbazolium bromide (4d) showed potent antitumor activities against P388 leukemia, colon 26, and Lewis lung carcinoma.

Animals↗
PubMed1997

Aromatase in human bone tissue.

Peripheral aromatization of androgens exert estrogenic actions in many tissues. Recently in situ production of estrogens by aromatase was detected in human bone and cultured osteoblasts and has been proposed to participate in the maintenance of bone mass. We examined aromatase expression by immunohistochemistry and mRNA in situ hybridization in 16 cases of tibia (female 2 male, 14 female, 62 +/- 5.2 years old) and quantified the level of aromatase mRNA in 28 cases of rib, femur, and lumbar vertebrae (16 male, 12 female, 58.0 +/- 11.3 years old) by reverse transcriptase-polymerase chain reaction (RT-PCR) in order to study whether or not and in which cell types aromatase was expressed in human bone tissues. We also studied alternative use of multiple exons 1 of its gene and immunolocalization of type I 17 beta-hydroxysteroid dehydrogenase (HSD), which converts estrone produced by aromatase to estradiol. Strong aromatase immunoreactivity and mRNA hybridization as well as type I 17 beta-HSD immunoreactivity were detected in lining cells, osteoblasts, chondrocytes of articular cartilage, and adipocytes adjacent to bone trabeculae in all the cases examined. Amounts of aromatase mRNA varied greatly among the subjects (11.25 +/- 9.77, 0.61-42.84 attomol/ng of total RNA). The amount of aromatase expression was not correlated with age or gender of the subjects but positively correlated with the degree of osteroporotic changes evaluated by radiological findings of lumbar vertebrae. Analysis of multiple exons 1 revealed that 1b or fibroblast type was predominantly (23/26) utilized as a promoter of aromatase gene expression. These results demonstrated that aromatase is expressed widely in human bone tissue and may play important roles in maintenance of human bone tissue.

17-Hydroxysteroid Dehydrogenases↗
PubMed1997

Pyruvate improves deleterious effects of high glucose on activation of pentose phosphate pathway and glutathione redox cycle in endothelial cells.

In our previous study (Diabetes 44:520-526, 1995), endothelial cells cultured in high glucose condition showed impairment of an oxidant-induced activation of the pentose phosphate pathway (PPP) and a reduced supply of NADPH to the glutathione redox cycle. To gain insight into the mechanisms of this impairment, the protective effect of pyruvate was studied in human umbilical vein endothelial cells cultured in either 5.5 mmol/l glucose (normal glucose [NG] condition) or 33 mmol/l glucose (high glucose [HG] condition). Through pretreatment of cells with 0.2 mmol/l pyruvate for 5-7 days in the HG condition, glucose oxidation through the PPP and total cellular NADPH content in the presence of 0.2 mmol/l H2O2 were increased by 54 (P < 0.05) and 34%, respectively, and glutathione-dependent degradation of H2O2 in HG cells was enhanced by 41% (P < 0.01), when compared with those cells to which pyruvate was not added. The addition of pyruvate significantly reduced the fructose 1,6-bisphosphate (FDP) content and free cytoplasmic NADH/NAD ratio, estimated by increased pyruvate/lactate ratio in NG and HG cells exposed to H2O2. Furthermore, the addition of pyruvate also showed a 46% reduction (P < 0.01) of endothelial cell damage induced by H2O2 in HG cells. These results indicate that abnormalities in PPP activation and glutathione redox cycle activity induced by H2O2 in HG cells are compensated, and that the accentuated reductive stress is improved by an addition of pyruvate. These pyruvate effects are associated with protection against an oxidant-induced endothelial cell injury in the high glucose condition.

Adenosine Triphosphate↗
PubMed1997

Response to psychological test in elderly patients with hand-arm vibration syndrome and healthy controls.

We investigated the parasympathetic nervous response to psychological test using heart rate variation (HRV) during deep breathing in elderly patients with hand-arm vibration syndrome and healthy controls. Average age (SD) of 16 patients with vibration-induced white finger (VWF), 13 patients without VWF and 12 healthy controls was 60.1 (2.8), 60.6 (4.2) and 58.8 (3.8), respectively. After an initial supine rest for 40 min, psychological test (Stroop color word test and mirror drawing test) was performed for 20 min. The indexes of HRV (Mean R-R, SD, RMSSD and CV) were calculated. Blood pressure and heart rate were also measured. The indexes of HRV did not differ between the groups before exposure. The SD, RMSSD and CV of the patients without VWF during supine deep breathing after 3 min post-exposure supine rest were significantly lower than those of the control group (p < 0.05). The Mean R-R of the patients without VWF significantly increased (p < 0.05). Blood pressure did not differ in either before or after exposure measurements. The results suggest that the post-exposure response of the parasympathetic nervous system to psychological test reduced in the patients without VWF.

Aged↗
PubMed1997

Extracellular ATP-induced Ca2+ mobilization of type I spiral ganglion cells from the guinea pig cochlea.

Intracellular calcium concentrations ([Ca2+]i) in type I cochlear spiral ganglion cells (SGCs) of the guinea pig were measured by digital imaging microscopy and the Ca(2+)-sensitive dye Fura-2. Extracellular ATP induced elevation of [Ca2+]i in type I SGCs in a concentration-dependent manner. The ATP-induced elevation of [Ca2+]i in SGC was even evident in the Ca(2+)-free solution, thereby suggesting that ATP induces a Ca(2+)-release from intracellular stores in SGCs. Suramin and reactive blue 2, both antagonists for the P2-purinergic receptor, inhibited the [Ca2+]i increase in SGCs induced by extracellular ATP in a dose-dependent manner. Adenosine did not induce any changes of [Ca2+]i in SGC. These results suggest that type I SGCs may possess P2-purinergic receptor but not P1-purinergic receptor. Extracellular ATP induced a [Ca2+]i increase in type I SGCs, with and without neuritic processes, while L-glutamate increased [Ca2+]i in type I SGCs with neuritic processes, but not SGCs without neuritic processes. The ATP-induced [Ca2+]i increase was almost equal in both soma and processes. Therefore, the distribution of P2-purinergic receptor in type I SGCs may be homogeneous in soma and processes. Based on these observations, we suggest that extracellular ATP may act as a neurotransmitter or neuromodulator of the hair cell-afferent nerve synapse in the guinea pig cochlea.

Adenosine↗
PubMed1997

Histamine-induced calcium released from cultured human mucosal microvascular endothelial cells from nasal inferior turbinate.

Changes in cytosolic Ca2+ concentration ([Ca2+]i) in cultured human mucosal microvascular endothelial cells (HMMECs) from nasal inferior turbinate were measured using a fluorescent Ca(2+)-sensitive dye, fura-2, and photometric fluorescence microscopy. Histamine caused a transient increase in intracellular free Ca2+ in cell populations and in individual cells, followed by a decrease to a sustained elevation. Histamine (100 microM) elevated [Ca2+]i in HMMECs up to 563 +/- 20 nM from a resting level of 60 +/- 45 nM (means +/- SD, n = 31). Promethazine (a histamine H1 receptor antagonist) inhibited [Ca2+]i increase during histamine stimulation, whereas cimetidine (a H2 receptor antagonist) and thioperamide (a H3 receptor antagonist) showed no inhibition. These results suggest that the histamine increase [Ca2+]i in HMMECs induces both a Ca2+ release from stores and a Ca2+ influx through activation of the H1 receptor.

Calcium↗
PubMed1997

Reduction of spinal cord injury by administration of iloprost, a stable prostacyclin analog.

To investigate whether iloprost, a stable analog of prostacyclin, is useful for the prevention of posttraumatic spinal cord injury, we examined its effects on compression trauma-induced spinal cord injury in rats. Spinal cord injury was induced by applying a 20-g weight for 20 minutes to the spinal cord at the level of T-12, resulting in motor disturbances in the hindlimbs. These motor disturbances, evaluated using Tarlov's index, were markedly attenuated in rats with nitrogen mustard-induced leukocytopenia. Administration of iloprost also attenuated the motor deficits. Histological examination revealed that intramedullary hemorrhages observed 24 hours after trauma were significantly attenuated in leukocytopenic animals and in animals that received iloprost. The accumulation of leukocytes at the site of trauma, evaluated by measuring tissue myeloperoxidase activity, significantly increased with time following the trauma, peaking at 3 hours postinjury. Spinal cord myeloperoxidase activity in sham-operated animals did not increase postoperatively. Leukocyte depletion and administration of iloprost reduced the accumulation of leukocytes in the damaged spinal cord segment 3 hours posttrauma. These findings indicate that iloprost attenuates motor disturbances induced by spinal cord trauma and that its therapeutic efficacy can be partly explained by its inhibition of leukocyte accumulation at the traumatized site.

Animals↗
PubMed1997

Tyrosine phosphorylation of platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31) in mechanically stimulated vascular endothelial cells.

Fluid flow triggers signal transducing events, modulates gene expression, and remodels cytoskeletal structures in vascular endothelial cells (ECs). However, the primary steps of mechanoreception are still unknown. We have recently reported that a glycoprotein is rapidly tyrosine-phosphorylated in bovine ECs exposed to fluid flow or osmotic shock. Here were cloned a 3.4 kb cDNA encoding this protein and found that this was bovine PECAM-1. The tyrosine-phosphorylation level of PECAM-1 immunoprecipitated from mechanically stimulated bovine or human ECs increased. The PECAM-1 phosphorylation was not induced by reagents that triggered Ca2+ mobilization in ECs. An autophosphorylatable band comigrating with c-Src was co-immunoprecipitated with anti-PECAM-1, and c-Src phosphorylated and bound to a GST fusion protein containing the PECAM-1 cytoplasmic domain. A spliced mRNA form lacking amino acid residues 703-721 in the cytoplasmic domain was also expressed in bovine ECs, c-Src neither phosphorylated nor bound to the fusion protein containing the spliced PECAM-1 cytoplasmic domain which lacked one (Tyr 713) of the six tyrosine residues in the PECAM-1 cytoplasmic domain. These results suggest that the YSEI motif containing Tyr 713 is the Src phosphorylation/binding site. Our study is the first demonstration of inducible tyrosine phosphorylation of PECAM-1 and suggests involvement of PECAM-1 and Src family kinases in the sensing/signal transduction of mechanical stimuli in ECs.

Amino Acid Sequence↗