Biomedical subjects

K Nagata

Publications and source records attributed to K Nagata.

At least 361 records · Page 20Linked to original sources

PubMed1997

Synthetic study of phosphopeptides related to heat shock protein HSP27.

Two kinds of phosphoserine-containing peptides related to HSP27 were synthesized by the Boc- or Fmoc-mode solid-phase method based on prephosphorylation strategy. In the case of the Boc strategy, the O-phosphono group of the phosphoserine residue was protected with the cyclopentyl or cyclohexyl group. On the other hand, N'-Fmoc-O-[(benzyloxy)-hydroxyphosphinyl]serine was employed in case of the Fmoc strategy. Consequently, it has become-feasible to utilize conventional solid-phase methods for synthesizing any phosphopeptides which are required to elucidate biochemical significance of protein phosphorylation.

Chromatography, High Pressure Liquid↗

PubMed1997

The Ig alpha/Igbeta heterodimer on mu-negative proB cells is competent for transducing signals to induce early B cell differentiation.

The immunoglobulin alpha (Ig alpha)/Ig beta heterodimer was detected on the surface of mu-negative proB cell lines in association with calnexin. The cross-linking of Ig beta on proB cells freshly isolated from bone marrow of recombination activating gene (RAG)-2-deficient mice induced a rapid and transient tyrosine-phosphorylation of Ig alpha as well as an array of intracellular proteins including Syk, PI3-kinase, Vav, and SLP-76. It also elicited the phosphorylation and activation of a MAP kinase ERK but not JNK/SAPK or p38. When RAG-2-deficient mice were treated with anti-Ig beta monoclonal antibody, developmentally arrested proB cells were induced to differentiate to the small preB cell stage as observed when the mu transgene was expressed in RAG-2-deficient mice. Thus, the cross-linking of Ig beta on proB cells appears to elicit differentiation signals analogous to those delivered by the preB cell receptor in normal B cell development.

Animals↗

PubMed1997

The roles of preB cell receptor in early B cell development and its signal transduction.

The preB cell receptor is expressed for a short period after mu heavy chain is produced, that is, at the large preB cell stage in B cell development. The severe impairment of B cell differentiation observed in mice deficient for the preB cell receptor clearly demonstrated the importance of the preB cell receptor in B cell development. Analyses of bone marrow precursor B cells in normal and B cell-deficient mutant mice indicated the preB cell receptor transduced signals to drive cell cycle and to induce allelic exclusion. The proliferation of the preB cell receptor-expressing cells leads to the selective expansion of cells which have succeeded in the productive rearrangement of mu heavy chain gene. This process builds up a preB cell pool large enough to generate sufficient numbers of mature B cells. The preB cell receptor appears to induce allelic exclusion by shutting off the expression of recombinase activation gene (RAG). In order to analyse the signal transduction pathway downstream of the preB cell receptor, we have developed a new system in which cross-linking of Ig beta expressed on bone marrow proB cells mimics the signalling through the preB cell receptor to induce differentiation from proB to small preB cells.

Alleles↗

PubMed1997

Establishment of a novel human acute myeloblastic leukemia cell line (YNH-1) with t(16;21), t(1;16) and 12q13 translocations.

The t(16;21)(p11;q22) translocation is a non-random chromosomal aberration observed in several types of human acute myeloblastic leukemia (AML), whereas the der(16)t(1;16) and chromosome rearrangements at 12q13 are frequently found in solid tumors. A novel cell line YNH-1 was established from peripheral blood cells of a 46-year-old male with AML (M1) carrying t(16;21) and t(1;16) translocations. YNH-1 has been maintained with a doubling time of 82 h for more than 20 months as a granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3) dependent line. Morphologically YNH-1 cells were free-floating immature myeloblasts with lobulated nuclei and vacuoles in the cytoplasm. They were positive for myeloperoxidase but negative for alpha-naphthyl butylate esterase and chloroacetate esterase stainings. In surface marker analysis YNH-1 cells were positive for CD13, CD33 and CD34. Chromosomal analysis showed 46, XY, der(16)t(16;21)(p11;q22)t(1;16) (q12;q13), der(21)t(16;21)(p11;q22), der (6)t(6;12)(q13;q13), der(12)t(6;12)(q21;q13). These translocations were confirmed by fluorescence in situ hybridization (FISH) studies with the ERG-YAC clone and chromosome-specific DNA libraries. Both the FUS/ERG and ERG/FUS chimeric transcripts were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. Thus, YNH-1 could be a useful tool for elucidating the pathophysiology and molecular mechanism in AML with t(16;21),t(1;16) and 12q13 translocations.

Amino Acid Sequence↗

PubMed1997

Objective evaluation of pain in various spinal diseases: neuropeptide immunoreactivity in the cerebrospinal fluid.

A quantitative analysis was performed of substance P-like immunoreactivity (SPLI) and of beta-endorphin-like immunoreactivity (beta-ENDLI), in the cerebrospinal fluid (CSF) in various diseases. The results reported to date have not been consistent. The purpose of this study was to investigate whether or not the concentration of SPLI or that of beta-ENDLI in CSF demonstrated any potential for assessing the degree of subjective pain in various spinal diseases. SPLI in CSF was measured by radioimmunoassay in 158 patients with a spinal disease; involving 57 patients with a lumbar disc herniation (LDH), 38 with lumbar canal stenosis (LCS), 46 with cervical myelopathy (CM) and 17 with cervical radiculopathy (CR), and also in 20 healthy controls. beta-ENDLI in CSF was measured in 25 of these same patients; involving 12 with LDH, seven with LCS and six with CM, and also five of the same controls. The concentration of serum SPLI was also measured in 50 of these 158. The severity of pain was self-evaluated by each patient using a linear visual analogue scale (VAS). Their Japanese Orthopaedic Association (JOA) score was also calculated objectively using the clinical findings. Correlations were investigated among the concentrations of SPLI and beta-ENDLI in the CSF and the VAS and JOA clinical assessments of these patients. The concentration of SPLI in CSF was significantly higher in various spinal diseases than in control (P < 0.05), and was correlated with the severity on the VAS and with the JOA score. However, beta-ENDLI was not correlated with either the VAS or the JOA score. We conclude that the measurement of the SPLI concentration in CSF has the potential for assessing objectively the severity of pain associated with various spinal diseases.

Activities of Daily Living↗

PubMed1997

Establishment of a novel human myeloid leukaemia cell line (HNT-34) with t(3;3)(q21;q26), t(9;22)(q34;q11) and the expression of EVI1 gene, P210 and P190 BCR/ABL chimaeric transcripts from a patient with AML after MDS with 3q21q26 syndrome.

A novel human myeloid leukaemia cell line (HNT-34) was established from the peripheral blood of a 45-year-old female patient with acute myelogenous leukaemia (AML) transformed from chronic myelomonocytic leukaemia (CMMoL) with 3q21q26 syndrome. Morphologically, the HNT-34 cells were undifferentiated blasts which were negative for myeloperoxidase. The HNT-34 cells were positive for CD4, CD13, CD33 and CD34, but negative for CD41a and CD42b. The cells actively proliferated in suspension with a doubling time of 26-27h in the absence of any growth factors. Neither proliferative advantage nor differentiation was observed with the addition of G-CSE GM-CSF, IL-3, TPO, DMSO or PMA. Cytogenetic analysis showed 46,XX. t(3;3)(q21;q26), t(9;22)(q34;q11),20q-. Molecular analysis showed expression of EVI1 gene, P210 and P190 BCR/ABL chimaeric transcripts. The chromosomal breakpoint at 3q26 of HNT-34 cell line was located to approximately 200 kb 5' of FIM3 locus and more upstream of the MDS1. which is the same region as that of somatic cell hybrid line H10C. The breakpoint at 3q21 was located within the 390 kb centromeric from the breakpoint cluster region. These results suggest that the HNT-34 cell line may be a useful tool for the elucidation of the mechanisms of leukaemogenesis which involve the 3q21q26 syndrome and Ph1 chromosome.

Antigens, Surface↗

PubMed1997

An experimental model of intraoperative venous injury in the rat.

Intraoperative obliteration of cerebral veins occasionally causes unexpected severe complications, especially in elderly patients. However, very title information is available on the pathophysiology of cerebral venous circulation disturbance. Occlusion of cortical veins in rats by a photochemical thrombotic technique is a less invasive, clinically relevant and reproducible model that is suitable for the study of venous circulation disturbance. In the present study, 54 male Wistar rats were used. We examined changes of the cerebral venous flow pattern by fluorescence anglography and brain damage histologically in a one- or two-(cortical) vein occlusion model using a photochemical thrombotic technique. Approximately 30% (9 of 27) of animals in the single-vein occlusion group and 90% (15 of 17) of those in the two-vein occlusion group had microcirculation perturbation, which results very soon in the formation of venous thrombus accompanied by severe venous infarction. In addition, infarction size in the two-vein occlusion group (9.7 +/- 3.2%) was significantly larger than in the single-vein group (2.9 +/- 1.3%) (unpaired T-test, P < 0.01).In conclusion, the photochemical dye technique of attaining cerebral venous occlusion is a worth while addition to the study of circulation perturbations of the brain.

Journal Article↗

PubMed1997

Fasudil (HA1077), an intracellular calcium antagonist, improves neurological deficits and tissue potassium loss in focal cerebral ischemia in gerbils.

The effects of an intracellular calcium antagonist fasudil (HA 1077) on protein synthesis, ion derangement, brain edema, and the neurological signs associated with focal cerebral ischemia, were investigated via a nine-hour occlusion of the left common carotid artery (CCA) in Mongolian gerbils. Protein synthesis was evaluated by the amount of incorporation of [14C]methionine into the tissue. Intravenous infusion of fasudil hydrochloride (1 mg kg-1) just after CCA ligation was effective in reducing neurological deficits six and nine hours after CCA ligation, as well as loss of tissue potassium. However, fasudil did not ameliorate the brain edema or the accumulation of sodium in the tissue. On the other hand, fasudil improved the uptake of [14C]methionine, but not its incorporation into the tissue. The improved uptake of tracer into the tissue may indicate the facilitation of collateral blood flow by fasudil. These results suggest that fasudil may mitigate ischemic damage in the penumbral zone, possibly by ameliorating collateral blood flow and preventing calcium-related cell damage.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

PubMed1997

Molecular cloning and characterization of rat ST1B1 and human ST1B2 cDNAs, encoding thyroid hormone sulfotransferases.

Human and rat cDNAs encoding thyroid hormone sulfotransferases have been isolated from their liver cDNA libraries. The isolated sulfotransferases, termed rat ST1B1 and human ST1B2, share 77 and 74% homologies at nucleotide and deduced amino acid levels. These forms showed less than 36 and 56% homologies to hydroxysteroid and aryl sulfotransferases, indicating that they constitute a new gene subfamily of aryl sulfotransferase. Expression of ST1B1 and ST1B2 in COS-1 cells resulted in the appearance of 33.0 and 32.5 kDa proteins, respectively, whose mobilities were identical with proteins detected in rat and human livers in Western blots using antibodies raised against ST1B1 and ST1B2 produced in Escherichia coli. The recombinant forms catalyzed sulfation of p-nitrophenol, 3,3',5-triiodothyronine (T3) and dopamine, but not of beta-estradiol and dehydroepiandrosterone. ST1B1 and ST1B2 showed higher affinities for formation of T3 sulfate (apparent Km 40.2 and 63.5 microM, respectively) than did thermostable phenol sulfotransferase ST1A3 (apparent Km 413 microM) or thermolabile phenol sulfotransferase ST1A5 (apparent Km 180 microM). These data indicate that the newly characterized sulfotransferases constitute a distinct ST1 subfamily of enzymes catalyzing the sulfation of T3 as a typical endogenous substrate in rats and humans.

Amino Acid Sequence↗

PubMed1997

Effect of dobutamine and OPC-18790 on diastolic chamber stiffness in patients with idiopathic dilated cardiomyopathy.

We investigated the acute effects of the positive inotropic agents (dobutamine and a novel phosphodiesterase inhibitor OPC-18790) on left ventricular diastolic chamber stiffness in patients with idiopathic dilated cardiomyopathy (DCM). We obtained pressure-volume (PV) data before and after drug administration in 17 patients with DCM by using a conductance catheter with a micromanometer tip. Patients were randomly assigned to receive intravenous infusions of dobutamine (2.5-7.5 micrograms/kg body weight per min, n = 8) or OPC-18790 (5-10 micrograms/kg body weight per min, n = 9). The dynamic diastolic chamber stiffness constant was calculated from a steady-state beat. The passive diastolic chamber stiffness constant was determined from the end-diastolic PV relation determined during transient inferior vena caval occlusion. Dobutamine and OPC-18790 similarly improved left ventricular end-systolic elastance (Ees) and left ventricular isovolumic relaxation time constants. The dynamic diastolic chamber stiffness constant decreased significantly in both the dobutamine (0.0934 +/- 0.0271 to 0.0685 +/- 0.0248; p < 0.01) and OPC-18790 (0.0843 +/- 0.0477 to 0.0569 +/- 0.0246; p < 0.05) groups. The passive diastolic chamber stiffness constant decreased significantly in the OPC-18790-treated group (0.0211 +/- 0.0114 to 0.0144 +/- 0.0117; p < 0.005) but not in the dobutamine-treated group (0.0197 +/- 0.0130 to 0.010186 +/- 0.0102; p > 0.05). Thus both dobutamine and OPC-18790 reduced the dynamic diastolic chamber stiffness constant, but only OPC-18790 reduced the passive diastolic chamber stiffness constant. OPC-18790 had a favorable effect on diastolic function in patients with DCM, compared with that of dobutamine. The passive diastolic chamber stiffness obtained from the end-diastolic PV relations represents more likely passive chamber properties than the dynamic diastolic chamber stiffness obtained from traditional single-beat analysis.

Adult↗

PubMed1997

HSF4, a new member of the human heat shock factor family which lacks properties of a transcriptional activator.

Heat shock transcription factors (HSFs) mediate the inducible transcriptional response of genes that encode heat shock proteins and molecular chaperones. In vertebrates, three related HSF genes (HSF1 to -3) and the respective gene products (HSFs) have been characterized. We report the cloning and characterization of human HSF4 (hHSF4), a novel member of the hHSF family that shares properties with other members of the HSF family yet appears to be functionally distinct. hHSF4 lacks the carboxyl-terminal hydrophobic repeat which is shared among all vertebrate HSFs and has been suggested to be involved in the negative regulation of DNA binding activity. hHSF4 is preferentially expressed in the human heart, brain, skeletal muscle, and pancreas. Transient transfection of hHSF4 in HeLa cells, which do not express hHSF4, results in a constitutively active DNA binding trimer which, unlike other members of the HSF family, lacks the properties of a transcriptional activator. Constitutive overexpression of hHSF4 in HeLa cells results in reduced expression of the endogenous hsp70, hsp90, and hsp27 genes. hHSF4 represents a novel hHSF that exhibits tissue-specific expression and functions to repress the expression of genes encoding heat shock proteins and molecular chaperones.

Amino Acid Sequence↗

PubMed1997

Ruptured dissecting aneurysm as a cause of subarachnoid hemorrhage of unverified etiology.

BACKGROUND AND PURPOSE: The clinical features of "aneurysmal" subarachnoid hemorrhage (SAH) of angiographically unverified etiology were reviewed to clarify the incidence and natural history of dissecting aneurysms as the hemorrhagic source of SAH. METHODS: We reviewed 30 patients with SAH of unverified etiology in whom initial CT scan showed a diffuse or anteriorly distributed subarachnoid blood clot. Ten of the patients had stenotic or occlusive lesions (SOCL) on initial angiography, and these were the main focus of this study. RESULTS: Among the 10 patients with SOCL on initial angiography, the lesions were located on the anterior circulation in 6 and on the posterior circulation in 4. Ruptured dissecting aneurysms were confirmed by exploratory surgery or autopsy in 6 patients. Subsequent rupture occurred in 6 of the 10 patients (60%), and all 6 of these patients died as a result. CONCLUSIONS: The incidence (6/30) of dissecting aneurysms as the cause of SAH of unverified etiology was unexpectedly high, especially when initial angiography disclosed SOCL (6/10). The moribund patients with SOCL showed a high rate of rebleeding, and the untreated recurrent hemorrhages were fatal. Further MRI study is indicated for these patients to demonstrate the intramural hematoma. Compared with the devastating mortality caused by the subsequent ruptures, the extent of surgical morbidity was minor. Surgical intervention could therefore be justified when the following neuroradiological findings are present: (1) SOCL evident on angiography, (2) distribution of SAH on CT compatible with the location of the SOCL, and (3) intramural hematoma on MRI in the same region as the SOCL.

Adult↗

PubMed1997

Heat shock protein 72 level decreases during sleep in patients with obstructive sleep apnea syndrome.

Patients with obstructive sleep apnea syndrome (OSAS) suffer from stresses related to repetitive apneas during sleep. To examine whether the level of 72 kDa heat shock protein (HSP72) increases during sleep, 11 OSAS patients (apnea-hypopnea index: 63.5 +/- 36.1, mean +/- SD) underwent polysomnography and their peripheral blood mononuclear cells (PBMC) were isolated before, during, and after sleep. HSP72 level was determined by Western blotting and hsp72 mRNA level was quantified by Northern blotting. Nine normal subjects without OSAS were examined as normal controls. HSP72 level decreased progressively during sleep and its level at 8:00 A.M. was 78.0 +/- 17.5% of that at 8:00 P.M. (p < 0.01). No such decrease was seen in normal subjects. When OSAS patients received nasal continuous positive airway pressure (NCPAP) therapy, HSP72 level did not decrease significantly. In untreated OSAS patients, hsp72 mRNA level decreased during sleep (p < 0.01). When OSAS patients were treated with NCPAP therapy, the decrease in hsp72 mRNA level was not observed. HSP72 level before sleep in OSAS patients was higher than that in normal subjects (p < 0.01). We concluded that repetitive apneas caused high HSP72 level before sleep in OSAS patients and that NCPAP therapy had significant effect on HSP72 levels during sleep.

Blotting, Northern↗

PubMed1997

Mutations within the reactive-site region of human pancreatic secretory trypsin inhibitor confer alpha-thrombin and factor Xa inhibitory activities.

Mutations were introduced into the reactive-site region of human pancreatic secretory trypsin inhibitor (PSTI) to produce thrombin and/or factor Xa inhibitors. All of five mutants showed trypsin inhibitory activity as strong as wild-type PSTI. Moreover, the Arg (P1), Pro-Arg (P2-P1), and Pro-Arg-Ile-Tyr-Asn (P2-P1-P1'-P2'-P3') (bold letters indicated replaced amino acids compared to the wild type) mutants had additional inhibitory activities toward factor Xa, both thrombin and factor Xa, and thrombin, respectively, at 1 x 10(-5) M.

Antithrombins↗

PubMed1997

Mitogenic activity of Clostridium perfringens enterotoxin in human peripheral lymphocytes.

Clostridium perfringens enterotoxin (CPE) was found to possess interferon (IFN)-producing and mitogenic activities to human peripheral blood mononuclear cells. Both activities were demonstrated only in the T lymphocyte-rich fraction from healthy volunteers. The IFN produced appeared to be gamma-type since the activity of the IFN was neutralized by antiserum against human IFN-gamma. With formalin-treated CPE, the IFN-producing and mitogenic activities were weakly found. Similar findings were also obtained in the mouse lethality and cytotoxicity to Vero (African green monkey) cells, suggesting that the biological activities of the CPE molecule may be existing on the similar (or the same) sites. From these findings, human peripheral T cells may be one of useful reagents to study the mode of action of CPE since CPE was found to be a T cell mitogen which is supposed to be a superantigen.

Adult↗

PubMed1997

An improved canine model of subarachnoid hemorrhage using intrathecal indwelling catheters.

In the present study, the feasibility of intrathecal indwelling catheters in the preparation of a repeated subarachnoid hemorrhage (SAH) model in dogs, as well as chronic intrathecal administration of therapeutic agents against the ensuing cerebral vasospasm was examined. Briefly, through a small suboccipital incision, two catheters were introduced into the subarachnoid space so that their tips were positioned in the prepontine cistern. One was used to induce SAH by infusing autologous blood, and the other to administer pharmacological agents (saline and/or saline containing a dye in this study) by means of an osmotic pump. The occurrence of cerebral vasospasm was followed by angiography via the catheter placed in the vertebral artery. The obtained results show: i) the injected blood effectively formed a subarachnoid clot in the prepontine cistern, invariably leading to the occurrence of severe cerebral vasospasm of the basilar artery; ii) the fluid injected by the osmotic pump was evenly distributed in the cisterns around the brain stem; iii) on post mortem pathological examination, no injury of the brain or the major arteries ascribable to the placement of catheters was found. Therefore, the present model is considered to be useful for both the investigation of pathophysiology and therapy of cerebral vasospasm following SAH, to be more favorable from the standpoint of animal protection, and more convenient and reliable than those used until now.

Angiography↗

PubMed1997

Hemarthrosis of the knee and bone contusion.

We present five patients with acute traumatic hemarthrosis of the knee who also had hemorrhage within the bone marrow around the knee detected by magnetic resonance imaging. No additional bony, ligamentous, meniscal or osteochondral injuries were evident from clinical examination, initial and repeated plain radiographs, or magnetic resonance imaging. The main symptoms were sharply localized pain and tenderness of the contused area. When hemarthrosis was demonstrated at the first office visit, three cases had fat droplets in the blood. Two patients with hemarthrosis of the knee undergoing arthroscopy showed no obvious lesions of intra-articular structures. Instead they showed congestion of the joint capsule located in accordance with the traumatic episode. Magnetic resonance imaging demonstrated marrow abnormalities as diffusely low and high signal intensity areas in T1-weighted and T2-weighted images, respectively, in locations consistent with the traumatic episode and the symptoms. These disappeared within an average of 13 weeks (range in 4 cases, 12 to 16 weeks). These findings were considered diagnostic of bone contusion. Symptom duration was about 2 weeks in all cases. In conclusion the clinician should consider the possibility of coexisting bone contusion in cases of acute traumatic hemarthrosis of the knee with no evidence of bone or intra-articular lesions on clinical examination and conventional radiographs.

Adolescent↗

PubMed1997

Stress fracture of the medial malleolus.

It is difficult to assess the healing of the medial malleolar stress fracture. We describe a case of medial malleolar stress fracture which was monitored its healing with repeated magnetic resonance images.

Adolescent↗