Biomedical subjects

K Murata

Publications and source records attributed to K Murata.

At least 289 records · Page 16Linked to original sources

PubMed1997

STAM, signal transducing adaptor molecule, is associated with Janus kinases and involved in signaling for cell growth and c-myc induction.

We previously identified a putative signal transducing adaptor molecule, named STAM, that contains an Src homology 3 (SH3) domain and immunoreceptor tyrosine-based activation motif (ITAM). In this report, we demonstrate the functional significance of STAM in cytokine-mediated signal transduction. STAM is associated with Jak3 and Jak2 tyrosine kinases via its ITAM region and phosphorylated by Jak3 and Jak2 upon stimulation with IL-2 and GM-CSF, respectively. An SH3 deletion mutant of STAM confers a dominant-negative effect on DNA synthesis mediated by IL-2 and GM-CSF. Furthermore, the wild-type STAM, but not STAM mutants deleted of SH3 and ITAM, significantly enhances c-myc induction mediated by IL-2 and GM-CSF. These results strongly implicate STAM in the signaling pathways for cell growth and c-myc induction immediately downstream of the Jaks associated with the cytokine receptors.

Adaptor Proteins, Signal Transducing↗

PubMed1997

Cellular distribution of a natural killer cell tumour recognition-related surface antigen in purified human lymphocytes.

Natural killer (NK) cells are large granular lymphocytes capable of human leucocyte antigen (HLA) unrestricted killing of tumour cells. A putative NK cell tumour-recognition molecule (NK-TR) was previously isolated and cloned. The predicted primary structure of the NK-TR revealed that the amino terminus of the protein shared high homology with cyclophilin proteins. In this study, we used rabbit antibodies directed against synthetic peptides corresponding to amino acids 476-497 of the NK-TR protein, to examine the expression of the NK-TR antigen in freshly purified human lymphocytes. Cell-surface staining experiments using these peptide antibodies indicated the presence of the NK-TR protein on the surface of human CD3+ T-cell populations purified from peripheral blood. There were individual donor differences in the levels of cell-surface expression of this antigen ranging from 35 to 90% in T lymphocytes and, NK cells purified from different healthy volunteers. The immunoreactivity of our peptide antibodies in immunoprecipitation showed that the NK-TR-related protein expressed in purified T cells is similar to that expressed in NK cells in terms of its electrophoretic mobility. Cell-surface staining experiments using the peptide antibodies revealed that the NK-TR-related protein is more abundantly expressed on the surface of purified T cells compared with NK cells. Northern blot analysis of the mRNA species transcribed in human lymphocytes revealed abundant expression of NK-TR-specific mRNA species in purified T cells. Furthermore, another mRNA species smaller than 7 kb was detected in both NK and T-cell populations of lymphocytes freshly isolated from peripheral blood. Expression at the cell surface of a cyclophilin-homologous protein in purified human T lymphocytes may indicate another function for the reported NK-TR protein, that is, distinct from tumour-cell recognition and cytosis.

Antigens, Surface↗

PubMed1997

Differential localization of myosin and myosin phosphatase subunits in smooth muscle cells and migrating fibroblasts.

Myosin II light chains (MLC20) are phosphorylated by a Ca2+/calmodulin-activated kinase and dephosphorylated by a phosphatase that has been purified as a trimer containing the delta isoform of type 1 catalytic subunit (PP1C delta), a myosin-binding 130-kDa subunit (M130) and a 20-kDa subunit. The distribution of M130 and PP1C as well as myosin II was examined in smooth muscle cells and fibroblasts by immunofluorescence microscopy and immunoblotting after differential extraction. Myosin and M130 colocalized with actin stress fibers in permeabilized cells. However, in nonpermeabilized cells the staining for myosin and M130 was different, with myosin mostly at the periphery of the cell and the M130 appearing diffusely throughout the cytoplasm. Accordingly, most M130 was recovered in a soluble fraction during permeabilization of cells, but the conditions used affected the solubility of both M130 and myosin. The PP1C alpha isoform colocalized with M130 and also was in the nucleus, whereas the PP1C delta isoform was localized prominently in the nucleus and in focal adhesions. In migrating cells, M130 concentrated in the tailing edge and was depleted from the leading half of the cell, where double staining showed myosin II was present. Because the tailing edge of migrating cells is known to contain phosphorylated myosin, inhibition of myosin LC20 phosphatase, probably by phosphorylation of the M130 subunit, may be required for cell migration.

Amino Acid Sequence↗

PubMed1997

Hilar and mediastinal invasion of bronchogenic carcinoma: evaluation by thin-section electron-beam computed tomography.

The diagnostic accuracy of thin-section incremental dynamic computed tomography (IDCT) using an electron-beam scanner in evaluating hilar or mediastinal invasion of bronchogenic carcinoma was assessed. Thirty-seven patients with proven bronchogenic carcinoma, contiguous with hilar or mediastinal structures, underwent IDCT. The area of contact was scanned using 19 contiguous 3-mm thick sections during injection of contrast material. The degree of contact between mass and pulmonary artery or vein and their distortion were recorded. Irregular thickening of the bronchial wall, soft tissue within the lumen, or distortion were used to determine airway involvement. Sixty-nine sites were assessed retrospectively and compared with pathology reports. The accuracy, sensitivity, and specificity in evaluating invasion of the pulmonary artery were 75.0%, 77.8%, and 71.4%, respectively. Limited reliability also was found for invasion of the main bronchus and "secondary" carina, with accuracies of 66.7% and 70.5%, sensitivities of 75.0% and 70.0%, and specificities of 57.1% and 71.4%, respectively. Thin-section IDCT with electron beam scanner is not accurate in the detection of hilar or mediastinal invasion by bronchogenic carcinoma.

Adult↗

PubMed1997

In vivo retrovirus-mediated herpes simplex virus thymidine kinase gene therapy approach for adult T cell leukemia in a rat model.

We have previously demonstrated that human T-lymphotropic virus type I (HTLV-I) tax-expressing human T cell lines are selectively eliminated in the presence of aciclovir, using a retroviral vector carrying the herpes simplex virus thymidine kinase (HSV TK) gene under the control of the long terminal repeat (LTR) of HTLV-I. Based on these findings in vitro, we investigated whether this system could also be effective in vivo, using a rat model. Following infection of the HTLV-I-transformed and tax-expressing rat T cell line TARS-1 with this retrovirus (LNLTK virus), high levels of HSV TK expression were observed and resulted in increased susceptibility to ganciclovir (GCV). Tumors were generated by subcutaneous injection of TARS-1 in newborn syngeneic WKA/H rats. While the tumors derived from infected TARS-1 cells with control virus, as well as uninfected cells, continued to grow in all the rats with or without administration of GCV, those derived from LNLTK-infected cells exhibited dramatic regression upon GCV treatment. These results indicate that the HTLV-I LTR-HSV TK system also causes selective elimination of HTLV-I-transformed, tax-expressing T cells in vivo. Therefore, our present study may provide a rationale for clinical gene therapy against adult T cell leukemia.

Animals↗

PubMed1997

Adequacy of pacing rate during exercise in rate responsive ventricular pacing.

Our objective was to determine the adequate pacing rate during exercise in ventricular pacing by measuring exercise capacity, cardiac output, and sinus node activity. Eighteen patients with complete AV block and an implanted pacemaker underwent cardiopulmonary exercise tests under three randomized pacing rates: fixed rate pacing (VVI) at 60 beats/min and ventricular rate-responsive pacing (VVIR) programmed to attain a heart rate of about 110 beats/min or 130 beats/min (VVIR 110 and VVIR 130, respectively) at the end of exercise. Compared with VVI and VVIR 130, VVIR 110 was associated with an increased peak oxygen uptake (VVIR 110: 20.3 +/- 4.5 VVI: 16.9 +/- 3.1; P < 0.01; and VVIR 130: 19.0 +/- 4.1 mL/min per kg, respectively; P < 0.05 and a higher oxygen uptake at anaerobic threshold (15.3 +/- 2.7, 12.7 +/- 1.9; P < 0.01, and 14.6 +/- 2.6 mL/min per kg; P < 0.05). The atrial rate during exercise expressed as a percentage of the expected maximal heart rate was lower in VVIR 110 than in VVI or VVIR 130 (VVIR 110: 75.9% +/- 14.6% vs VVI: 90.6% +/- 12.8%; P < 0.01; VVIR 110 vs 130: 89.1% +/- 23.1% P < 0.05). There was no significant in cardiac output at peak exercise between VVIR 110 and VVIR 130. We conclude that a pacing rate for submaximal exercise of 110 beats/min may be preferable to that of 130 beats/min in respect to exercise capacity and sympathetic nerve activity.

Cardiac Output↗

PubMed1997

Advanced gastric carcinoma in a de Brazza's guenon (Cercopithecus neglectus).

A necropsy case of advanced gastric carcinoma in a 20-year-old female de Brazza's guenon (Cercopithecus neglectus) was studied, Grossly, an excavated carcinoma mass, 60 x 55 x 35 mm in size, was located in the cardiac region of the stomach. Multiple disseminated nodules had implanted on the diaphragm and omentum. The tumor consisted of intestinal-type adenocarcinoma cells and showed infiltrative growth beyond the serosa. The morphologic features of this tumor closely resembled those of advanced gastric carcinomas in human patients.

Adenocarcinoma↗

PubMed1997

Pulmonary hilar lymph node metastases from lung cancer: evaluation based on morphology at thin-section, incremental, dynamic CT.

PURPOSE: To evaluate the usefulness of a new computed tomographic (CT) criterion for diagnosing hilar lymph node metastases on the basis of the margin between hilar interstitium and lung parenchyma. MATERIALS AND METHODS: The morphology of normal and metastatic hilar nodes was analyzed in seven inflated and fixed human lung specimens. Thin-section, incremental, dynamic CT was then performed preoperatively in 95 patients with lung cancer, and the margins of peribronchovascular hypoattenuated areas were evaluated in 22 of the patients with normal hila. CT-pathologic comparisons were performed at 179 locations where interstitium touched lung parenchyma. The comparison was based on a new CT criterion in which convex interstitial margins indicate nodal metastases. RESULTS: The margins of the interstitia with normal nodes were concave or straight at 94.8% (183 of 193) of the contact sites in the six normal specimens and at 97.3% (436 of 448) of the contact sites on CT scans, whereas the margins of the interstitia with abnormal nodes were convex at 94.7% (54 of 57) of the contact sites in the abnormal specimen. Sensitivity, specificity, and accuracy of three reviewers who used the new criterion were 87.3%, 88.3%, and 88.1%, respectively. CONCLUSION: The new CT criterion is useful for the diagnosis of hilar node metastases in lung cancer.

Humans↗

PubMed1997

Deletions of p15 and/or p16 genes as a poor-prognosis factor in adult T-cell leukemia.

PURPOSE: To determine the frequency of the deletions of p15/p16 genes in adult T-cell leukemia (ATL) cells and to evaluate their value in the diagnosis of clinical subtypes of ATL patients and the prediction of their clinical outcome. MATERIALS AND METHODS: Peripheral-blood samples from 114 patients with ATL were examined by Southern blot analysis. In five chronic-type patients who showed disease progression to acute type, serial samples also were examined. RESULTS: Among 114 patients, 28 (24.6%) showed the deletions of p15 and/or p16 genes. The results were well correlated with the clinical subtypes. Patients with deleted p15 and/or p16 genes had significantly shorter survival times than the patients in whom both genes were preserved (P < .0001). A similar decline in survival time was observed in the analyses within the same subtypes. In multivariate analysis using the Cox proportional hazard model, the deletions of p15 and/or p16 genes emerged as an independent prognostic indicator. Moreover, three of the five chronic-type patients who progressed to acute type lost the p16 gene alone or both the p15 and p16 genes at their exacerbation phase. CONCLUSION: The results suggest the following: (1) that the deletions of p15 and/or p16 genes play a key role in the progression of ATL; and (2) that these deletions are reliable prognostic factors that predict shortened survival times.

Adult↗

PubMed1997

Effect of additives on dissolution and swelling of soybean lecithin microcapsules prepared using the Wurster process.

Microcapsules whose membranes contained soybean lecithin (SL), cholesterol (CH), stearic acid (SA) and polyvinylpyrrolidone (PVP) at various compositions were prepared. Then, dissolution and swelling behaviors of the microcapsules in a 0.9% saline solution were studied to be related to the phase diagram of three components containing 42% of PVP in anhydrous state. In the aqueous solution, when an anhydrous microcapsule membrane was composed of SL not saturated with both CH and SA, the microcapsules showed rapid release of carbazochrome sodium sulfonate (CCSS, a model drug), poor particle-swelling and spouting of droplets containing CCSS. Long-delayed release of CCSS and drastic particle-swelling with no spouting of droplets were observed when the anhydrous membrane was composed of SL saturated with both CH and SA and the composition was not close to the two-component line, CH-SA, or to the saturation line. The spouting of droplets would be attributable to the CH and/or SA-poor SL phase and to the SL phase which dissolved CH and SA, but contained either CH or SA only in a small amount, and the delayed release would be due to the CH and SA-rich SL phase dissolving a great amount of CH and SA formed by hydration. The degree of release suppression and particle-swelling depended on the SL content. At 20-45% of SL content, the prolonged-release, great particle-swelling and no spouting of droplets at the early stage were observed only when the CH and SA-rich SL phase formed by hydration contained a high content of CH and SA.

Adrenochrome↗

PubMed1997

[Pharmacological properties of pteleprenine, a quinoline alkaloid from Orixa japonica (Rutaceae), in guinea pig ileum and canine left atrium].

We investigated the pharmacological properties of pteleprenine, a quinoline alkaloid contained in the Rutaceous plant, Orixa japonica, on the contractile responses of the guinea pig ileum and on the inotropic responses of the canine left atrium. Contractile responses of the ileum to acetylcholine and histamine were not inhibited by less than 10(-6) M of pteleprenine. Meanwhile, the nicotine induced-contraction of the ileum was dose-dependently diminished by pteleprenine, but the contractile response to nicotine did not reach the maximum value in the presence of 10(-5) M of pteleprenine. The pA2 value of pteleprenine was 6.6 as determined from the Schild plot, which slope was nearly unity. Furthermore, the contraction of the ileum by 10(-5) M of 1,1-dimethyl-4-phenylpiperazinium (DMPP), a specific agonist of nicotinic acetylcholine receptors, was also dose-dependently suppressed by pteleprenine. On the other hand, 10(-5) M of pteleprenine did not have considerable inhibitory effects on acetylcholine- and nicotine-induced negative inotropic effects in the canine left atrium. From these results, it is suggested that pteleprenine has a specific inhibitory effect on nicotinic acetylcholine receptors in the guinea pig ileum.

Alkaloids↗

PubMed1997

Horseshoe lung: demonstration by electron-beam CT.

Horseshoe lung is a rare pulmonary anomaly characterized by fusion of the posterobasal portions of the right and left lungs behind the pericardial reflection, anterior to the aorta. The majority of reported cases occur in conjunction with scimitar syndrome, including hypoplasia of the right lung, anomalous right pulmonary venous return and systemic arterial supply to the lung. Horseshoe lung is usually diagnosed on pulmonary arteriography when the right inferior pulmonary artery crosses the midline and extends to the left lung base. Bronchography is also diagnostic when the branch of horseshoe portion arises from the right bronchus and passes within the lung parenchyma to midline of the lung tissue. The only described CT finding of horseshoe lung is the contiguity of the right and left lungs behind the heart. Most cases are infants under 12 months of age and CT images are severely hampered by respiration motion artefacts. Such artefacts are minimized by using electron-beam computed tomography, allowing a more detailed CT appearance of horseshoe lung in this case.

Child, Preschool↗

PubMed1997

[Pulse phenomenon of continuous white noise with interrupted pure tone].

The researches of masking made it clear that there is a bandpass like a filter in the auditory system. This is called the auditory filter and its central frequency is thought to be the frequency of an acoustic signal. If there exist this kind of filter, the authors expected that the noise image which is perceived when pure tone and noise simultaneously presented is different from the one which is perceived when noise is presented independently. The authors chose an interrupted pure tone as an acoustic signal and continuous white noise as noise, and experimented to investigate the pure tone effect on perception of white noise. As a result, two stimulus tones induced three sound images, which are sound images of continuous noise, a pure tone and pulsed noise. The sound image which listeners did not expect to hear was the pulsed noise image. This phenomenon was thought to be an auditory induction; the inducer is the sound image of the white noise presented with the silent part of pure tone of interrupted pure tone and the inducee is that of the white noise presented with pure tone part of interrupted pure tone. This pulse phenomenon suggests that pure tone change the loudness of white noise. This finding is interesting for researches of auditory mechanism and for the field of hygienics with protecting the auditory system and improving hearing under the noisy environment.

Acoustic Stimulation↗

PubMed1997

Identification of the sex of Oriental white stork, Ciconia boyciana, by the polymerase chain reaction based on its sex chromosome-specific DNA sequences.

Southern blotting of HindIII-digested genomic DNAs from the female and male Oriental white stork (Ciconia boyciana) with the EE0.6 probe cloned from the W chromosome of chicken (Gallus domesticus) produced a 3.0-kb W chromosome-derived band specific to the female and a 3.5-kb Z chromosome-derived band common to both sexes. These two genomic fragments were cloned and the counterpart sequences to that of EE0.6 in these fragments, XH0.6 and XH0.6RSM (XH0.6-related sequence in the male), respectively, were subcloned. Nucleotide sequences of XH0.6 and XH0.6RSM showed 92% identity. PCR using a set of primer sequences from XH0.6, which differed several nucleotides from those in XH0.6RSM, amplified an about 300-bp genomic sequence only from the female C. boyciana. This method was applied successfully to identify the sex of individual young birds of C. boyciana, an endangered special natural monument in Japan and whose sexes are unidentifiable from their external morphology.

Animals↗

PubMed1997

Inhibitory effect of alginic acids on hyaluronidase and on histamine release from mast cells.

The effects of various types of alginic acid consisting of L-guluronic acids (G) and D-mannuronic acids (M) on hyaluronidase and mast cell degranulation were examined. Alginic acid with an M/G ratio of 1.0 exhibited the strongest inhibition of both activities, the higher molecular weight alginic acids of 150 to 370 kDa being preferable in both cases. Esterification of the carboxyl residue enhanced the latter activity.

Alginates↗

PubMed1997

Purification and characterization of extracellular poly(beta-D-1,4-mannuronide) lyase from Dendryphiella salina IFO 32139.

An extracellular endo poly(beta-D-1,4-mannuronide) lyase of Dendryphiella salina IF 32139 was purified to homogeneity by Q Sepharose FF and Sephacryl S-200 HR column chromatographies. The purified enzyme had a molecular weight of 35,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and an isoelectric point of 3.65 by isoelectric focusing. The optimum pH and temperature for enzyme activity were pH 5.0 and 45 degrees C, respectively. The enzyme was stable from pH 4 to 10 and at temperature below 40 degrees C. Some divalent cations, Ca2+, Mn2+, and Zn2+, increased the enzyme activity. Hg2+ and NBS strongly inhibited the activity. This enzyme susceptibly degraded poly-M, produced a wide range of 4,5-unsaturated oligomannuronic acids, and further degraded these unsaturated oligomannuronic acids to produce the unsaturated monomer and dimer as final products.

Amino Acid Sequence↗

PubMed1997

First record of Eustrongylides tubifex (Dioctophymatidae) from little grebe, Tachybaptus ruficollis in Japan.

A nematode species belonging to the genus Eustrongylides (Dioctophymatidae) was obtained from the proventriculus of Tachybaptus ruficollis, found in December, 1995 in Kobe City, Hyogo Prefecture, Japan. Observation under a scanning electron microscope to investigate anterior extremity with the labial papillae in two circles showed that this species is identical to E. tubifex. This is the first record of this species in Japan.

Animals↗

PubMed1997

Long-term evaluation of combined antihypertensive therapy with lisinopril and a thiazide diuretic in patients with essential hypertension.

For the treatment of hypertension, the combination of an angiotensin-converting enzyme (ACE) inhibitor and a thiazide diuretic is supported by multiple lines of evidence, because these drugs have synergistic action and are expected to cancel out each other's adverse side effects. However, the long-term outcome of this combination antihypertensive therapy is not entirely clear. In the present multicenter open trial, we investigated the long-term efficacy and safety of combined antihypertensive therapy with an ACE inhibitor, lisinopril, and a thiazide diuretic, trichlormethiazide. A total of 466 patients with essential hypertension were treated with lisinopril alone (monotherapy group, n = 360) or with a combination of lisinopril with trichlormethiazide (combination therapy group, n = 106) for 1 year. The average blood pressure was effectively lowered to below 150/90 mmHg in both the monotherapy and the combination therapy groups throughout the study period. The average maintenance dose of lisinopril was lower when combined with thiazide than when given alone (9.8 vs. 11.5 mg/day, p < 0.001). Dry cough was the major side effect of lisinopril; no severe adverse effects were observed. The incidence of cough was not significantly different between the monotherapy group (13.1%) and the combination therapy group (11.3%). The increase in serum potassium observed in the monotherapy group was reversed by the concurrent use of the thiazide diuretic in the combination therapy group. Fasting blood glucose was significantly reduced in the monotherapy group; the reduction observed in the combination therapy group was not significant. Thus, the present results provide useful information as to the effectiveness and safety of combined antihypertensive therapy with lisinopril and a thiazide in comparison with monotherapy with lisinopril.

Adult↗