Search PubMed⌕ Search

Biomedical subjects

K Murase

Publications and source records attributed to K Murase.

At least 235 records · Page 13Linked to original sources
PubMed1988

Actions of calcitonin gene-related peptide on rat sensory ganglion neurones.

The membrane actions of calcitonin gene-related peptide (CGRP) and the effect of CGRP on the Ca-dependent action potential of rat dorsal root ganglion (DRG) neurons have been studied by means of an intracellular recording technique in isolated DRG of 2-3-week-old rats in vitro. Bath application of CGRP (10(-8)-10(-6) M for 1-5 min) elicited a slow reversible hyperpolarization and this hyperpolarizing effect was still observed in the medium containing TTX and TEA. However, about half of the large cells, classified by duration of action potential, were depolarized by CGRP. These membrane effects of CGRP were associated with an increase in membrane input resistance (about 20%). In addition, CGRP increased the duration of Ca-dependent action potentials. Our results are consistent with the role of CGRP as an excitatory neurotransmitter or neuromodulator in DRG-spinal cord.

Animals↗
PubMed1988

[Left ventricular volume curve analysis using gated blood pool emission computed tomography].

Analysis of the left ventricular volume curve was performed using gated blood pool emission computed tomography (SPECT) in six patients with old myocardial infarction (MI), five with hypertrophic cardiomyopathy (HCM), three with dilated cardiomyopathy (DCM), and five normal controls (N). Image collection was synchronized with the QRS complex, and each cardiac cycle was divided into nine to 10 frames. In each frame, left ventricular volume was determined based on the number of voxels above the threshold level (50% cut-off level), and the volume curve was fitted to the third harmonics of Fourier analysis. From the fitted curve, the peak ejection rate (PER), the peak filling rate (PFR), end-diastolic volume (EDV), end-systolic volume (ESV) and ejection fraction (EF) were calculated. 1. There were good correlations between SPECT and the conventional gated blood pool (MUGA) for PER (r = 0.694, p less than 0.005), PFR (r = 0.527, p less than 0.025) and EF (r = 0.682, p less than 0.005). 2. PER in MI (2.21 +/- 0.55, mean +/- SD) was lower than in N (3.68 +/- 0.80, p less than 0.05) and HCM (4.85 +/- 2.39, p less than 0.05), and EF in MI (36.6 +/- 6.4) was lower than in HCM (68.7 +/- 23.7, p less than 0.05). 3. There were good correlations between EDVs (y = 1.11x + 5.71, r = 0.877, p less than 0.01), and ESVs (y = 1.05x - 3.88, r = 0.876, p less than 0.01) estimated by MUGA and SPECT.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

[A study involving early carcinomas of the gall bladder].

In recent years, with the development of diagnostic procedures, the number of cases of early carcinoma of the gall bladder has been seen to gradually increase. In this paper, 8 cases of early gall bladder carcinoma have been evaluated, using a diagnostic approach. Cholecystolithiasis was the complication in 6 cases, and abdominal pain was seen as the most common symptom. Findings by various image diagnoses, such as ultrasonography, DIC, ERCP, and CT scan are described and discussed with a review of literature. Ultrasonography was considered to be the most useful tool for the detection and diagnosis of an early carcinoma of the gall bladder. A survey is thought to be required, involving the cases that have accumulated throughout the entire nation.

Adenocarcinoma↗
PubMed1988

Pharmacological properties of the orally active leukotriene antagonist [[5-[[3-(4-acetyl-3-hydroxy-2-propylphenoxy)-propyl]thio]-1,3,4- thiadiazol-2-yl]thio]acetic acid.

The anti-leukotriene effect of [[5-[[3-(4-acetyl-3-hydroxy -2- propylphenoxy)propyl] thio]-1,3,4-thiadiazol-2-yl] thio] acetic acid (YM-16638) was examined. In isolated guinea-pig ileum, YM-16638 antagonized the contractions induced by slow reacting substance of anaphylaxis (SRS-A) and leukotriene D4 (LTD4) with IC50 values of 6.0 x 10(-8) and 1.1 x 10(-7) mol/l, respectively. However, the compound at 10(-5) mol/l did not affect the contractions induced by histamine, acetylcholine, 5-hydroxytryptamine, prostaglandin (PG)E2 and PGF2 alpha. In isolated guinea-pig trachea, YM-16638 inhibited the contractions elicited by LTC4, LTD4 and LTE4 and its IC50 values were 5.7 x 10(-8), 1.6 x 10(-7) and 9.6 x 10(-8) mol/l, respectively. In isolated human bronchi, YM-16638 also antagonized the contractions induced by LTC4, LTD4 and LTE4 and its IC50 values were 6.0 x 10(-8), 1.2 x 10(-7) and 2.1 x 10(-8) mol/l, respectively. YM-16638 at the doses of 3 to 100 mg/kg p.o. inhibited the skin reaction induced by LTD4 in conscious guinea-pigs and its ED50 value was 17.9 mg/kg p.o. Successive oral administration of YM-16638 (50 mg/kg/d) for 10 days did not develop tolerance in its inhibitory effect against LTD4-induced skin reaction. Furthermore, the compound at the doses of 10 and 30 mg/kg p.o. significantly inhibited the antigen-induced bronchoconstriction in conscious guinea-pigs pretreated with mepyramine, propranolol and indomethacin. These results indicate that YM-16638 is a selective, potent and orally active leukotriene antagonist.

Animals↗
PubMed1987

Simulation and experimental study of respiratory motion effect on image quality of single photon emission computed tomography (SPECT).

The effect of respiratory motion on the image quality of single photon emission computed tomography (SPECT) was investigated by computer simulation and experimentation. In the computer simulation, the phantom was assumed to be cylindrical with a uniform background and a spherical cold or hot spot. To simulate respiratory motion, a cyclic linear motion parallel to the axis of rotation of a gamma camera was assumed. The contrast in the transaxial images was calculated for various respiratory amplitudes and its dependence on lesion size and object contrast was investigated. In the experiments, a moving phantom was used to simulate respiratory motion. The simulation and the experimental results were in good agreement within the range of statistical error. The effect on the lesion detectability was investigated using receiver operating characteristics (ROC) analysis, and a method for correcting respiratory motion was devised.

Computer Simulation↗
PubMed1987

A comparative study of attenuation correction algorithms in single photon emission computed tomography (SPECT).

A computer based simulation method was developed to assess the relative effectiveness and availability of various attenuation compensation algorithms in single photon emission computed tomography (SPECT). The effect of the nonuniformity of attenuation coefficient distribution in the body, the errors in determining a body contour and the statistical noise on reconstruction accuracy and the computation time in using the algorithms were studied. The algorithms were classified into three groups: precorrection, post correction and iterative correction methods. Furthermore, a hybrid method was devised by combining several methods. This study will be useful for understanding the characteristics, limitations and strengths of the algorithms and searching for a practical correction method for photon attenuation in SPECT.

Algorithms↗
PubMed1987

Monte Carlo estimates of absorbed dose rate in various tissues and organs.

A computer program based on the Monte Carlo technique was developed for calculation of absorbed dose rate in various tissues and organs. The accuracy of the program was tested by reproducing Berger's values of the specific absorbed fractions for point isotropic sources in water, and a good agreement with those obtained by the moments method was found within an error of several percent. In comparing with experiment and other Monte Carlo results, good agreement was also obtained within the range of statistical error. The absorbed dose rate for an 123I, 124I, 125I, 126I and 99mTc point source and their specific dose constants in various tissues and organs were calculated using this program. This computer program has the mass energy absorption and attenuation coefficients for 69 tissues and organs as a database file, and can be extended to various radionuclides used in nuclear medicine by adding their nuclear data to the program.

Humans↗
PubMed1987

Proliferation and immunoglobulin synthesis of peripheral blood mononuclear cells from patients with chronic liver disease stimulated by Staphylococcus aureus Cowan 1 and interleukin 2.

Proliferation and IgG synthesis of peripheral blood mononuclear cells (PBMC) in response to stimulation with recombinant interleukin 2 (IL-2) and Staphylococcus aureus Cowan 1 (SAC) were evaluated in 32 patients with chronic persistent hepatitis (CPH), chronic active hepatitis (CAH) and liver cirrhosis (LC). Eleven patients had serum HBe antigen, 10 presented with HBe antibody and 11 had non-A, non-B hepatitis. IgG synthesis of PBMC induced with the two stimuli was significantly decreased in patients with CAH and LC when compared with that of controls. However, the generated amounts of IgG were not associated with the HB virus carrier state. B cells and T4+ cells were responsible for the diminished IgG synthesis in patients with CAH and LC when assessed by coculture experiments. On the other hand, proliferative response of PBMC to IL-2 and SAC were similar in controls and patient groups. These findings indicate that IgG production level of PBMC stimulated with IL-2 and SAC can reflect the severity of the underlying disease in chronic hepatitis patients.

Adult↗
PubMed1987

Autoantibodies against liver cell membrane antigens detected by enzyme-linked immunosorbent assay in acute and chronic liver disease.

An enzyme-linked immunosorbent assay was developed to detect serum antibody binding to liver membrane antigen derived from human hepatoma cell line SK-Hep-1. When we tested sera from 214 patients with this assay, IgM antibodies were detected in 100% of patients with acute type A, but not with type B or non-A, non-B hepatitis. IgM antibodies were also found in highest frequency (76%) and titer in patients with autoimmune chronic active hepatitis (CAH) among chronic liver disease groups. IgG antibodies occurred in over 50% of patients with acute type A hepatitis, type B chronic active liver disease (CALD), and autoimmune CAH. IgA antibodies were present in 43% of the patients with alcoholic liver disease, but were also seen in other patient groups. When freshly isolated rat hepatocytes were used as target cells, prevalences and titers similar to those obtained with SK-Hep-1 were found. The levels of serum membrane binding antibody were significantly reduced by the addition of human liver-specific membrane lipoprotein in all patient groups. In particular, IgM antibodies became negative in over 50% of patients with CALD (both type B and non-A, non-B) and autoimmune CAH, whereas in acute hepatitis over 50% lost their positivity for IgG antibody. These results indicate that circulating liver membrane binding autoantibodies are heterogeneous, occurring in hepatitis virus-induced acute and chronic liver disease as well as in autoimmune CAH.

Acute Disease↗
PubMed1987

Isolated tissue and binding studies of YM-17690, a novel and non-analogous leukotriene agonist.

YM-17690, 3-[4-carboxymethoxy-3-[p-(4-phenylbutoxy) benzamido]phenyl]propionic acid, produced a dose-dependent contraction of guinea-pig ileum and its EC50 value was 1.6 X 10(-8) M. The response was not affected by pretreatment with atropine, mepyramine, indomethacin, dazoxiben and AA-861 (a 5-lipoxygenase inhibitor), but was inhibited by FPL-55712 (an LTD4 and LTE4 antagonist). YM-17690 induced dose-dependent contractions of guinea-pig lung parenchyma and trachea with EC50 values of 3.9 X 10(-9) and 2.2 X 10(-8) M, respectively. Pretreatment of these tissues with FPL-55712 resulted in a parallel shift of the YM-17690 dose-response curves to the right. The pA2 values for FPL-55712 in lung parenchyma and trachea were 7.41 and 8.21, respectively, and the slopes of the regression lines of Schild plots were 1.00 and 1.02, respectively. YM-17690 produced a dose-dependent inhibition of [3H]LTD4 binding to guinea-pig lung membranes and its pKi value was 9.28. However, the compound showed only 25% inhibition of [3H]TLC4 binding to guinea-pig hippocampus membranes, even at 10(-5) M. These results suggest that YM-17690 is a selective leukotriene (LTD4 and LTE4) agonist and that it will therefore be a valuable tool in the study of actions of leukotrienes and for the characterization of their receptors.

Animals↗
PubMed1987

Natural killer and activated killer activities in chronic liver disease and hepatocellular carcinoma: evidence for a decreased lymphokine-induced activity of effector cells.

Natural killer (NK) and activated killer (AK) cells appear to be important in immunoregulation, elimination of virus-infected cells and resistance to tumours. NK activity against K 562 and AK activity against FL target cells of peripheral blood mononuclear cells (PBMC) from patients with chronic persistent hepatitis (CPH), chronic active hepatitis (CAH), liver cirrhosis (LC) and hepatocellular carcinoma (HCC) were investigated using 51Cr release assay. Spontaneous NK activity of patients with LC (P less than 0.05) and HCC (P less than 0.001) was decreased when compared to that of controls. The sera and PBMC from patients with low NK activity had no inhibitory effect on the NK activity of normal subjects. Indomethacin treatment significantly enhanced the NK activity of controls (P less than 0.05), whereas the drug did not affect that of patients with low NK activity. The percentages of PBMC that reacted with monoclonal antibodies anti-Leu-7 and anti-Leu-11a were similar in controls and patients. However, a Leu-11a+/Leu-7+ ratio, and NK activity of Leu-11+ and Leu-7+ cell-rich populations were significantly decreased in cirrhotic and HCC patients when compared to controls. Interleukin 2 boosted both NK and AK activities of patients, but to a lesser degree in comparison with those of controls when similarly stimulated. gamma-Interferon also significantly augmented NK and AK activities of patients, but the levels of cytotoxicity were lower in HCC patients (P less than 0.05) than those of controls. These findings suggest that the decreased NK and AK activities in chronic liver disease and HCC are due to an altered subpopulation ratio of NK cells and a functional defect of effector cells.

Adult↗
PubMed1986

Substance P augments a persistent slow inward calcium-sensitive current in voltage-clamped spinal dorsal horn neurons of the rat.

Rat spinal dorsal horn neurons in slice preparations perfused with Ringer solution containing 0.5-1 microM TTX and/or 10-20 mM tetraethylammonium at 29 degrees C, were studied by using a single microelectrode voltage-clamp technique. Slow persistent inward currents were recorded during depolarizing voltage commands to membrane potentials positive to about -40 mV. The inward current was depressed by removing external Ca, or by adding 0.1-0.2 mM Cd, 5 mM Co or 0.1 mM verapamil, and was increased by adding Ba or Bay-K 8644. Substance P (SP) augmented a persistent slow inward Ca-sensitive current in a dose-dependent manner. It is suggested that this effect may be instrumental in generating the SP-evoked slow depolarization, increase in membrane excitability, and the 'bursting' behavior in the immature rat dorsal horn neurons. In addition, in some neurons SP reduced the M-like current, which effect may contribute to, but not explain, generation of the SP-induced slow depolarization.

Animals↗