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Biomedical subjects

K Murase

Publications and source records attributed to K Murase.

At least 253 records · Page 14Linked to original sources
PubMed1986

In vitro synthesis of antibody to hepatitis B virus antigen by circulating lymphocytes from chronic HBsAg carriers and patients with acute hepatitis B.

It is not clear what determines the outcome of hepatitis B surface antigen (HBsAg) infection, although evidence suggests that the absence of antibody to HBsAg (anti-HBs) is responsible for the development of the carrier state. The synthesis of immunoglobulin G (IgG), anti-HBs and antibody to hepatitis B core antigen (anti-HBc) was measured in pokeweed mitogen-stimulated cultures of peripheral blood mononuclear cells from 12 chronic HBsAg carriers, 5 patients with acute hepatitis B (AHB) during recovery phase and 11 subjects with anti-HBs in serum (controls). All 3 groups showed similar amounts of IgG synthesis. Anti-HBc was detectable in lymphocyte cultures of 10 of 12 chronic HBsAg carriers and 2 of 5 AHB patients, but in none of the controls. Anti-HBs was found in cultures from 6 of 11 controls, and not in carriers or AHB patients. Both in vitro anti-HBc and anti-HBs levels correlated significantly with serum titers of anti-HBc and anti-HBs respectively. B cells from controls cocultured with irradiated (helper) T cells from carriers and AHB patients produced anti-HBs normally. In contrast, B cells from 11 of 12 carriers and 3 of 5 AHB patients cocultured with irradiated control T cells did not synthesize detectable amounts of anti-HBs although they synthesized normal amounts of IgG and anti-HBc. T cells from 8 of 12 carriers and all AHB patients suppressed anti-HBs synthesis by mixtures of control B cells and control irradiated T cells, but these T cells did not affect IgG synthesis.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗
PubMed1986

Imidazo[2,1-b]benzothiazoles. 2. New immunosuppressive agents.

A series of 2-phenylimidazo[2,1-b]benzothiazole derivatives was prepared and tested for immunological activities. Some of the compounds showed significant suppressive activity of delayed type hypersensitivity (DTH) without inhibition of humoral immunity in mice by oral administration. The most active compound was 2-(m-hydroxyphenyl)imidazo[2,1-b]benzothiazole (20).

Animals↗
PubMed1986

Enhancement of antibody production to hepatitis B surface antigen by anti-idiotypic antibody.

Studies were undertaken to determine whether anti-idiotypic antibody (anti-Id) against antibody to hepatitis B surface antigen (anti-HBs) could modulate in vitro anti-HBs production by human peripheral blood mononuclear cells stimulated with pokeweed mitogen. Peripheral blood mononuclear cells from patients positive for serum anti-HBs produced significantly increased amounts of anti-HBs by the addition of IgG fraction of anti-anti-HBs as well as purified HBsAg in a soluble form when compared to those in cultures with pokeweed mitogen alone. F(ab')2 but not Fc fragments of anti-anti-HBs significantly enhanced anti-HBs levels in cultures. Anti-anti-HBs or HBsAg alone, however, did not induce anti-HBs production. Anti-HBs production was not observed by the additions of these additives when peripheral blood mononuclear cells from chronic HBsAg carriers and control individuals were used. These findings indicate that anti-Id modulates the immune response to HBsAg.

Antibodies, Anti-Idiotypic↗
PubMed1986

Quantitative analysis of acute myocardial infarction using single photon emission computed tomography using technetium-99m pyrophosphate.

The usefulness of single photon emission computed tomography (SPECT) using technetium-99m pyrophosphate (99mTc-PPi) was evaluated in 15 patients with acute myocardial infarction. SPECT was performed with a rotating gamma camera after conventional planar images were made. Infarct size was measured from transaxial images of myocardial pyrophosphate uptakes. In each slice, the boundary was defined by subtracting 70 percent of the maximal counts and the number of voxels automatically counted. This subtraction rate was determined by phantom study and by comparing SPECT using 99mTc-PPi with thallium-201-gated myocardial scintigraphy (201Tl gated SPECT). The planar images showed diffuse uptakes in two of the 15 patients, and in these cases it was difficult to detect the infarct site. In contrast, SPECT images clearly imaged the infarct site consistent with the electrocardiographic findings, and they were definitely separated from the uptakes in the bones in all cases. Infarct size, ranging from 3.4 ml to 78.3 ml, correlated well with cumulative creatine kinase release (r = 0.84, p less than 0.01, y = 772x + 13900). Correlation of infarct size with peak serum creatine kinase level was also significant (r = 0.66, p less than 0.01, y = 10.6x + 693). In conclusion, SPECT with 99mTc-PPi is a useful means of investigating the spatial distribution of pyrophosphate uptake and of evaluating the size of myocardial infarction.

Aged↗
PubMed1984

Actions of substance P on rat spinal dorsal horn neurones.

The membrane actions of substance P (SP) and the effects on the Ca-dependent action potential of dorsal horn neurones have been investigated by means of intracellular recording techniques in the immature rat in vitro spinal cord slice preparation. Bath application of SP (2 X 10(-6) to 1 X 10(-5) M) induced a biphasic membrane response consisting of an initial hyperpolarization followed by a depolarization in about one-third of the cells examined. Initial hyperpolarization was not observed when synaptic activity was blocked by perfusing the slice with a tetrodotoxin-containing or low Ca, high Mg Ringer solution. This result is consistent with a presynaptic action of SP mediated through excitation of inhibitory interneurones. This interpretation was supported by recording of repetitive spontaneous inhibitory post-synaptic potential (i.p.s.p.)-like hyperpolarizing potentials during the initial hyperpolarization. When Co ions were used to block voltage-dependent Ca conductance and possible indirect presynaptic actions, SP induced only a small depolarization of membrane potential. It seems, therefore, that Ca conductance may have contributed to the depolarizing phase of the SP response, either through its mediation of synaptic transmission or through direct effects as a charge carrier for inward current. When tetrodotoxin was used, the SP-induced increase in neuronal input resistance was not modified, although depolarization was slightly diminished. In contrast, in medium containing tetrodotoxin and tetraethylammonium, the SP-depolarizing response was enhanced and accompanied by a small decrease in input resistance and firing of Ca spikes. These results suggest that SP-induced depolarization might be a consequence of a reduction in a voltage-dependent K conductance allowing Na and/or Ca conductances to dominate. SP modified the duration of Ca-dependent action potentials of dorsal horn neurones, the most consistent change being an initial dose-dependent and reversible decrease in the spike duration. The decrease in Ca spike duration was associated with a small reduction in the rate of rise and peak amplitude, and a significant parallel increase in dV/dt of the falling phase of the Ca spike. Our data indicate that the initial decrease in Ca spike duration was not due to the depolarizing action of SP, although shunting of the membrane resistance, either through presynaptic or post-synaptic mechanisms, has not been ruled out. Alternatively, these data are consistent with the possibility that SP shortens the duration of the Ca spike by decreasing a voltage-sensitive inward Ca current and/or augmenting an outward K current.(ABSTRACT TRUNCATED AT 400 WORDS)

Action Potentials↗
PubMed1984

[Epidemiological studies on multiple primary malignant tumors in Nagasaki City].

Ninety-four cases of multiple primary malignant tumors registered at the Nagasaki Tumor Registry during the period from 1973-1977 were studied. The crude incidence rate tended to be higher in atomic bomb survivors although the difference was not significant. The male:female ratio was 1:1.19. Cases in the sixth decade of life were dominant, the average age was somewhat lower in females than in males. Stomach cancer was observed in 48 patients (51.1%; triple malignancies in 8 cases (8.5%).

Adult↗
PubMed1983

The development of a radioimmunoassay for formoterol.

The development of a radioimmunoassay (RIA) for the beta 2-stimulant formoterol is described. The sensitivity of the method is 0.1 ng/ml in plasma and urine, when a 1-ml sample is used. The cross-reactivity of the antiserum with formoterol glucuronide was 30%. Since formoterol is metabolized extensively to formoterol glucuronide in rats, dogs and humans, extraction with ethyl ether prior to the radioimmunoassay was carried out. Satisfactory agreement was obtained for levels of formoterol in plasma and urine when they were determined by RIA and gas chromatography-mass spectrometry. The concentration of formoterol was determined in dog plasma and human urine after oral administration of formoterol fumarate to dogs (61 mcg/kg) and humans (40 mcg).

Adrenergic beta-Agonists↗
PubMed1983

An analysis of tibial component design in total knee arthroplasty.

An axisymmetric finite element model of the proximal tibia and cemented tibial component subject to nonaxisymmetric loading is presented. Model variations included polyethylene components and steel reinforced polyethylene components both with and without a central fixation post. Central fixation posts of 35 and 70 mm were modeled. A vertically oriented load applied unilaterally to the tibial component was found to generally cause the largest magnitude peak stresses within the various components of the structure. The addition of steel reinforcement to tibial components without central fixation post is predicted to significantly reduce stress levels within the polymethylmethacrylate and underlying cancellous bone. Although to a lesser extent, the addition of a relatively short central fixation post to the steel reinforced tibial component further reduced these stress levels. The longer steel central fixation post can appreciably reduce proximal cement and bone stress levels. The tibial component condylar width is predicted to have little effect on polymethylmethacrylate and cancellous bone stresses, with the exception that proximal tibial cancellous bone compressive stresses are reduced with wide steel reinforced components.

Biomechanical Phenomena↗
PubMed1983

An electroejaculator for the collection of semen from the domestic cat.

An electroejaculator for the collection of cat semen and for the evaluation of electroejaculation protocols is described. The electroejaculator contains an adjustable signal generator and allows for the precise control and monitoring of the electrical stimulus to the animal. The electroejaculator incorporates controls for the selection of the frequency, potential and waveform of the electrical stimulus and controls for either manual or automatic delivery of stimuli of specified characteristics to the rectal probe. In the automatic mode, the operator may also preset the rate and duration of stimulus application and the interval between successive stimuli. The electroejaculator output to the probe is controlled with an on-off foot-switch which allows for the collection of semen from an anesthetized cat by one operator. Diagrams of the functional block, the component circuits of the electroejaculator, and the accessories which facilitate the collection of cat semen are provided.

Journal Article↗
PubMed1983

Electrophysiological properties of rat spinal dorsal horn neurones in vitro: calcium-dependent action potentials.

1. The electrophysiological properties of dorsal horn neurones have been investigated in the immature rat in vitro spinal cord slice preparation. 2. Intracellular recordings from dorsal horn neurones show that direct or orthodromic stimulation generates action potentials followed by a brief after-hyperpolarization. Synaptic potentials were elicited by the activation of primary afferent fibres in the dorsal root. 3. Input resistance for dorsal horn neurones ranged from 48 to 267 M omega, and the membrane time constant was in the range of 4-19 ms. 4. In response to strong depolarizing currents dorsal horn neurones perfused with TTX and TEA frequently exhibit a slow regenerative depolarizing potential followed by a slow after-hyperpolarization. The depolarizing potential probably results from an influx of Ca. It is blocked by low concentration Ca, Co or Mn, and enhanced by high levels of extracellular Ca. 5. There is, in addition, a low-threshold Ca-dependent response which is activated at membrane potentials more negative than -65 mV and has a maximum rate of rise at the polarization level of about -80 mV. 6. The addition of Ba or TEA to the perfusing medium provided support for the Ca-dependence of the low- and high-threshold responses, and the lack of fast inactivation of the high-threshold Ca potential.

Action Potentials↗
PubMed1983

[Clinical studies of long acting amoxicillin in oral surgery].

Clinical studies with long acting amoxicillin (L-AMPC) have been carried out and the following results were obtained. 1. Forty-two patients with acute bacterial infections in the oral region were administrated orally L-AMPC at a daily dose of 1 gram. The clinical results obtained were classified as excellent in 3 cases, good in 28 cases, and the overall efficacy was 75.6%. 2. The antibacterial activity of AMPC was determined for 66 strains isolated from patients with oral infections. Of the strains tested, Gram positive cocci showed high sensitivity with MIC's less than 1.56 mcg/ml, while the sensitivity of PC resistance strains of S. aureus, K. pneumoniae and P. vulgaris was lower. 3. There was 1 case of transaminase elevation in the laboratory finding. 4. Five patients reported the following side effects, eruption 3, diarrhea 2, nausea 1, anorexia 1 and malaise 1. From the results of the present study, it is considered that L-AMPC is a useful antibiotic in the treatment of acute bacterial infections in oral region.

Adolescent↗
PubMed1983

[Acute B-cell lymphoblastic leukemia with Burkitt's lyphoma cells--a case report].

A 65-year-old man with acute lymphoblastic leukemia of B-cell origin is described. The patient had many distinctive features including a very high blast cell count, hepatomegaly, hemorrhagic diathesis and a fulminant clinical course. Immunological studies showed the blast cells to have surface characteristics of B-lymphoid cells (IgG kappa). These cells had moderate amounts of deeply basophilic cytoplasm without granules. Most cells contained empty cytoplasmic vacuoles (L3 according to the FBA classification). Autopsy confirmed wide-spread leukemia involving the bone marrow, spleen, liver, kidneys, lungs, adrenals, thyroid gland, stomach, rectum, root ganglia and lymph nodes. This case is an example of acute lymphoblastic leukemia with Burkitt's tumor cells (L3).

Aged↗
PubMed1982

Vasoactive intestinal polypeptide excites mammalian dorsal horn neurons both in vivo and in vitro.

Vasoactive intestinal polypeptide (VIP) applied by iontophoresis and/or pressure microinjection causes a strong excitation of more than 75% of all tested spinal neurons in laminae I-VII of both the cat intact spinal cord and the rat spinal cord slice preparation. In the cat intact spinal cord the excitation is not limited to a single population of neurons but is observed in all categories of units recognized in spinal preparations of cats in this area on the basis of their excitability by different kinds of cutaneous afferent input. In the rat spinal cord slice preparation, VIP depolarized dorsal horn neurons and increased their excitability. The depolarization was associated with a decrease in neuronal input resistance. These results are consistent with the possibility that VIP may have a physiological role in synaptic function, either as a transmitter or as a modulator.

Animals↗