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Biomedical subjects

T Takishima

Publications and source records attributed to T Takishima.

At least 217 records · Page 12Linked to original sources
PubMed1991

Chemical oxidant potentiates electrically and acetylcholine-induced contraction in rat trachea: possible involvement of cholinesterase inhibition.

To determine the roles of oxidants in airway responsiveness, we studied the effects of the chemical oxidant N-chlorosuccinimide (NCS) on the contractile responses to electrical field stimulation (EFS) and acetylcholine (ACh) in isolated rat tracheal smooth muscle segments. Effects of NCS on the contractile response to EFS (5 Hz, 20 sec of duration, 50 V) reached the maximum with a 60-min incubation time. NCS potentiated the contractile response to EFS, with a maximum effect at 3 x 10(-7) M and to ACh, with a maximum effect at 3 x 10(-6) M. Thus, at a concentration of 3 x 10(-6) M, NCS significantly decreased log ED50 concentration of ACh from a control value of -5.56 +/- 0.05 to -6.24 +/- 0.06. Physostigmine (10(-7) M), at a concentration that did not alter resting tension, mimicked NCS-induced effects on contractile responses to ACh and EFS with the greater degree of shift in the respective dose-response curves. However, NCS failed to alter dose-response curves to carbachol. Removal of the epithelium shifted the dose-response curves to ACh to lower concentrations, but NCS showed similar effects on dose-response curves to ACh with and without the epithelium. Active staining showed that both acetylcholinesterase (EC 3.1.1.7) and butyrylcholinesterase (EC 3.1.1.8) activities were found in the smooth muscle of the rat trachea. NCS inhibited both enzyme activities from rat tracheal homogenates in a concentration-dependent fashion. These results suggest that NCS potentiates cholinergically induced contraction by decreasing cholinesterase activity and that the oxidation of cholinesterase may cause hyperresponsiveness of airway smooth muscle by inhibition of the enzyme activity.

Acetylcholine↗
PubMed1991

A small airway pressure sensor for humans.

We developed a small airway pressure sensor for humans. This sensor catheter was introduced to the right lower lobe bronchus through a fiberoptic bronchoscope until the tip was wedged, at which point the bronchoscope was removed. We measured small airway pressure using this sensor. Simultaneously, we measured mouth flow, mouth pressure and transpulmonary pressure by the esophageal balloon technique during tidal breathing. The present method is called an anterograde method. By this method, we obtained central airway resistance and peripheral airway resistance. A significant increase in peripheral airway resistance, compared to normal subjects, has been confirmed as a symptom of chronic obstructive pulmonary disease.

Airway Resistance↗
PubMed1991

[Restrictive lung disease].

It was found that functional residual capacity (FRC) invariably decreased during inspiratory elastic loaded breathing and that its magnitude increased progressively with an increase in the intensity of the load. This response could not be explained by chemoreflexes nor neural reflexes. Because the sensation of dyspnea decreased at lowered FRC (FRC-0.5 liter) than that at FRC during elastic loading, we speculate that FRC decreased behaviorally during elastic loading to reduce the sensation of dyspnea. We found that the respiratory muscle became fatigued more easily at FRC than at lowered FRC during elastic loading. We therefore conclude that the decrease in FRC may be one of the compensatory mechanisms during elastic loaded breathing.

Functional Residual Capacity↗
PubMed1990

Histidine decarboxylase in human basophilic leukemia (KU-812-F) cells. Characterization and induction by phorbol myristate acetate.

The human leukemic cell line KU-812-F is known to differentiate into mature basophil-like cells under serum-free culture conditions. In the present study, the activity of histidine decarboxylase (HDC), a histamine-forming enzyme, in KU-812-F cells was found to be high, ranging from 10 to 57 pmol/min/mg protein. The great variation in HDC activity appeared to be due to different percentages and degrees of maturity of basophil-like cells during differentiation of this cell line. The enzyme was inhibited by alpha-fluoromethylhistidine but not by carbidopa, was unable to form dopamine from L-3,4-dihydroxyphenylalanine, and had a Km value for histidine of 0.27 mM, indicating that it was HDC and not aromatic amino acid decarboxylase. The HDC activity increased 1.8-fold when the cells were stimulated by phorbol myristate acetate, which is known to activate protein kinase C, and this increase was blocked by staurosporine, a potent inhibitor of protein kinase C.

Alkaloids↗
PubMed1990

[Clinical significance of I-123 IMP brain SPECT in children with brain diseases].

Single photon emission computed tomography (SPECT) of the brain using N-isopropyl p-I-123-iodoamphetamine (I-123 IMP) was performed in 43 children with suspected brain diseases. Forty-three children (25 males and 18 females), with an age range of 24 days-15 years (mean: 6.6 years), were included in the study. Six patients were subsequently diagnosed as normal. Early SPECT of the brain was performed 30 minutes after intravenous administration of 74-111 MBq (2-3 mCi) I-123 IMP using a rotating gamma camera equipped with a 30-degree slant hole and medium energy collimator. Transverse images were reconstructed by Shepp-Logan filtered back projection method with attenuation correction after spatial filtering using an 8th order Butterworth-Wiener filter. Findings of I-123 IMP SPECT were compared with those of X-ray computed tomography (CT) and electroencephalography (EEG). The results showed that 1) In I-123 IMP SPECT, abnormality was found in 30 out of 37 children with brain diseases. The incidence of abnormal findings in the 37 patients was 81% in I-123 IMP SPECT, 61% in X-ray CT, and 78% in EEG., 2) In both cryptogenic and secondary epilepsy, the incidence of abnormality was higher in I-123 IMP SPECT than in X-ray CT. (70% and 94% vs 50% and 81% respectively). Epileptic foci detected by EEG did not correspond with defects found using I-123 IMP SPECT in 27% of the patients., 3) In asphyxiated infants, a high incidence of abnormality was observed on both I-123 IMP SPECT (86%) and X-ray CT (86%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[The experience of a new double-catheter introducer for simultaneous bilateral internal iliac angiography].

We developed a new 8F catheter-introducer system designed for simultaneous insertion of two catheters into each internal iliac artery via a single puncture. This introducer has a common distal limb and a pair of proximal limbs connected in a Y-shaped fashion. Each of the proximal limbs has its own check valve and flushing side arm, through which one can pass two catheters separately. We succeeded in placing each of two catheters at desired sites in three cases of pelvic angiography. This system will be of great help in pelvic angiography and infusion-chemotherapy when bilateral catheterization is required.

Aged↗
PubMed1990

Chloride and potassium channels in U937 human monocytes.

Ionic channels in a human monocyte cell line (U937) were studied with the inside-out patch-clamp technique. A Ca2(+)-activated K+ channel and three Cl- -selective channels were observed. The Ca2(+)-activated K+ channel had an inward-rectifying current-voltage relationship with slope conductance of 28 pS, and was not dependent on membrane potential. Among the three Cl- channels, an outward-rectifying 28-pS channel was most frequently observed. The permeability ratio (Cl-/Na+) was 4-5 and CH3SO4- was also permeant. The channel became less active with increasing polarizations in either direction, and was inactive beyond +/- 120 mV. The channel, observed as bursts, occasionally had rapid events within the bursts, suggesting the presence of another mode of kinetics. Diisothiocyanatostilbene-disulfonic acid (DIDS) blocked the channel reversibly in a dose-dependent manner. The second 328-pS Cl- channel had a linear current-voltage relationship and permeability ratio (Cl-/Na+) of 5-6. This channel became less active with increasing polarizations and inactive beyond +/- 50 mV. DIDS blocked the channel irreversibly. The channel had multiple subconductance states. The third 15-pS Cl- channel was least frequently observed and least voltage sensitive among the Cl- channels. Intracellular Ca2+ or pH affected none of the three Cl- channels. All three Cl- channels had a latent period before being observed, suggesting inhibitory factor(s) present in situ. Activation of the cells with interferon-gamma, interferon-alpha A or 12-O-tetradecanoylphorbol-13-acetate (TPA) caused no change in the properties of any of the channels.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1990

Left ventricular end-systolic stress-volume index ratio in aortic and mitral regurgitation with normal ejection fraction.

To evaluate the left ventricular contractile state in regurgitant valvular disease with normal ejection fraction, we analyzed the end-systolic stress-volume index relationship (ESSVR) by means of cineangiography in 15 normal subjects, 11 patients with aortic regurgitation (AR), and 10 patients with mitral regurgitation (MR) whose ejection fraction (EF) was 60% or more. The end-systolic stress-volume index ratio in normal subjects was 5.57 +/- 0.60 kdyne/cm5/m2 (mean +/- standard deviation), and we defined the range including +/- 2 standard deviations of the ratio as the normal ESSVR range. Six patients with AR and five patients with MR placed inside the normal ESSVR range, termed AR IN and MR IN, but the remaining five patients with AR and MR placed to the right of the normal range, termed AR OUT and MR OUT. EF did not differ between patients with AR IN and AR OUT (69.4 +/- 5.4 verus 70.7 +/- 6.1%) and between MR IN and MR OUT (71.6 +/- 3.6 versus 71.1 +/- 7.9%). The EF of the subdivided groups with AR and MR also did not differ from that of normal subjects (70.7 +/- 7.3%). This finding showed that the left ventricular contractile state was depressed in patients with AR OUT and MR OUT despite a normal EF. In AR and MR the end-systolic stress and end-systolic volume index of OUT did not differ from those of IN, but the end-diastolic volume index of OUT was larger than that of IN (AR OUT 156.8 +/- 27.9 versus AR IN 110.8 +/- 24.1 ml/m2, MR OUT 160.5 +/- 44.7 versus MR IN 101.0 +/ 16.6 ml/m2; both p less than 0.05), and the regurgitant fraction of OUT was higher than that of IN (AR OUT 52.6 +/- 13.6 versus AR IN 29.7 +/- 13.3%, MR OUT 52.9 +/- 10.2 versus MR IN 30.2 +/- 11.4%; both p less than 0.05). In addition, there was a linear inverse correlation between the end-systolic stress-volume index ratio and the end-diastolic volume index in all subjects (r = -0.82, n = 36). In normal subjects there was a linear inverse correlation between end-systolic stress and the EF (r = -0.91, n = 15), but this relationship failed to separate patients with OUT from those with IN. Results of the present study suggest that some patients with AR and MR whose EF was normal had a depressed contractile state, and these patients had a large end-diastolic volume index and a high regurgitant fraction.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1990

Series distribution of mucociliary clearance of magnetized iron particles in anesthetized dogs.

Clearance of magnetic iron particles placed in the trachea, peripheral airway and alveoli was studied in anesthetized dogs. A retrograde catheter was inserted into a peripheral airway 2 mm in diameter. A thin vinyl tube was inserted into the peripheral airway from the chest wall through the retrograde catheter and 0.05 ml of saline containing 30 mg of iron oxide (Fe3O4) was instilled into either the peripheral airway or the trachea. Further, 30 mg of Fe3O4 solution was instilled with an injection needle into the alveoli. After magnetization from outside the chest wall, remanent magnetic fields (RMF) generated in the trachea, peripheral airway and alveoli were sequentially measured with a flux-gate magnetometer. The decay of RMF immediately after sequential magnetization shows clearance of Fe3O4 particles. Relaxation of RMF just before sequential magnetization is related to random misalignment of the particles. The fastest clearance was observed in the trachea, followed by the peripheral airway and the slowest was that in the alveoli. Exposure to isoproterenol resulted in increased clearance in the trachea and peripheral airway. However, relaxation was of similar magnitude and was not altered by isoproterenol throughout the entire airway. These results suggest that mechanisms responsible for clearance and relaxation in vivo are different and that clearance accelerates toward the central airway from alveoli and relaxation may be due to properties of the airway surface lining layer.

Animals↗
PubMed1990

Effect of surfactant on bioelectric properties of canine tracheal epithelium.

The functional significance of pulmonary surfactant in the airways is not well known and the effects of surfactant on bioelectrical properties of airway epithelium have not been investigated. In the present study, we examined the effect of synthetic surfactant (TR-14) or calf lung surfactant extract (surfactant TA) on transepithelial potential difference (PD) and short circuit current (SCC) in canine trachea. The conductance (G) was calculated as the ratio of SCC per open-circuited PD. The posterior membrane without muscular layer from canine trachea was mounted in an Ussing-type chamber, bathed with Krebs-Ringer buffer solution at 37 degrees C and gassed with 95% O2-5% CO2, pH 7.4. Treatment with mucosal surfactant produced an increase in both PD and SCC in a dose-dependent fashion. PD and SCC reached 132% and 124% of before control at 0.25 mg/ml after the addition of each surfactant respectively, whereas G remained unchanged. Both ouabain and furosemide abolished surfactant-evoked increases in PD and SCC, whereas amiloride did not alter the surfactant-evoked increases. No significant differences in the effect on bioelectric parameters were observed between TR-14 and surfactant TA. These findings suggest that lung surfactant affects bioelectrical properties and changes ion transport (Cl- secretion) across airway epithelium, probably through the activity of ion pumps in the cellular membrane.

Animals↗
PubMed1990

Coronary zero flow pressure and intramyocardial pressure in transiently arrested heart.

STUDY OBJECTIVE: The aim of the study was to examine the relation between zero flow pressure and intramyocardial pressure in the inner and outer layers of the myocardium. DESIGN: Zero flow pressure was obtained in maximally vasodilated excised hearts by decreasing perfusion pressure (at 2 mm Hg.s-1) during transient heart arrest. Intramyocardial pressures in inner and outer myocardium were measured simultaneously with needle tip pressure transducers at depths of 8.0(SD 2.6) and 3.3(1.2) mm from the epicardium respectively. Ventricular and atrial pressure could be controlled at will. EXPERIMENTAL MATERIAL: The excised hearts of eight mongrel dogs, body weight 14.0(0.8) kg, were used. MEASUREMENTS AND MAIN RESULTS: During left ventricular pressure elevation (0, 15, 30 mm Hg), zero flow pressures were 9.1(2.4), 13.8(2.2), and 19.1(5.1) mm Hg, respectively. Corresponding values of intramyocardial pressure at the outer myocardium were in good agreement with the zero flow pressures, at 9.1(3.4), 13.4(2.8), and 20.8(5.4) mm Hg. Values at the inner myocardium increased from 7.4(2.4) to 18.9(8.6) and 32.9(13.0) mm Hg. The latter two values were significantly higher than the corresponding values of zero flow pressure and intramyocardial pressure at the outer myocardium (p less than 0.05, p less than 0.01). In isotransmural pressure elevation, the three pressures increased almost equally. CONCLUSIONS: The results show that zero flow pressure is strongly affected by intramyocardial tissue pressure, and if uneven intramyocardial pressure distribution is present the value of zero flow pressure depends on the lower values of intramyocardial pressure.

Animals↗
PubMed1990

Different histamine actions in proximal and distal human coronary arteries in vitro.

STUDY OBJECTIVE: The aim was to investigate the receptor mechanisms for different histamine actions in proximal and distal human coronary arteries. DESIGN: Postmortem human coronary rings precontracted by 50 mM KCl were exposed to histamine (10(-8)-10(-4) M) in control and after treatment with 10(-5) M pyrilamine (an H1 receptor antagonist), or 10(-4) M cimetidine (an H2 receptor antagonist), and/or endothelial removal. Tension changes at the point of maximum relaxation (at 10(-5) M in most rings) were obtained. MEASUREMENTS AND RESULTS: Endothelium dependent relaxations to histamine were clearly distinguished from endothelium independent relaxations by their transient nature and their inhibition by pyrilamine, but not by cimetidine. While most distal rings (group I, n = 42/58) and only some of the proximal rings (group II, n = 10/83) showed greater than 50% relaxation with histamine, nearly half the proximal rings (group III, n = 40/83) showed only contraction. Significant differences were found between group I and III, but not II, in control [-66(SD 15.2)% v +25(20.4)%, p less than 0.001] and after pyrilamine treatment [-66(9.2)% v -25(12.0)%, p less than 0.001], cimetidine treatment [-30(25.5)% v +42(20.9)%, p less than 0.001] and endothelial removal [-24(37.1)% v +36(20.2)%, p less than 0.01]. However, a combination of cimetidine and endothelial removal resulted in a contraction to histamine which was similar among the three groups. CONCLUSIONS: These results suggest that hypercontractility to histamine was found in proximal human coronary arteries, but not in distal ones, probably due to the reduction of both direct and endothelial mediated relaxations rather than to an increase in the contraction itself.

Adolescent↗
PubMed1990

Three-dimensional quantitative coronary angiography.

A method for reconstructing the three-dimensional coronary arterial tree structure from biplane two-dimensional angiographic images is presented. This method exploits the geometrical mathematics of X-ray imaging and the tracking of leading edges of injected contrast material into each vessel for identification of corresponding points on two images taken from orthogonal views. Accurate spatial position and dimension of each vessel in three-dimensional space can be obtained by this reconstruction procedure. The reconstructed arterial configuration is displayed as a shaded surface model, which can be viewed from various angles. Such three-dimensional vascular information provides accurate and reproducible measurements of vascular morphology and function. Flow measurements are obtained by tracking the leading edge of contrast material down the three-dimensional arterial tree. A quantitative analysis of coronary stenosis based on transverse area narrowing and regional blood flow, including the effect of vasoactive drugs, is described. Reconstruction experiments on actual angiographic images of the human coronary artery yield encouraging results toward a realization of computer-assisted three-dimensional quantitative angiography.

Algorithms↗
PubMed1990

Inhibitory actions of prostaglandin E1 on non-adrenergic non-cholinergic contraction in guinea-pig bronchi.

We have investigated the effect of prostaglandin E1 (PGE1) on non-adrenergic, non-cholinergic (NANC) contraction in guinea-pig bronchial strips. PGE1 (10 nM to 10 microM) did not alter baseline tension but reduced NANC contractions induced by electrical field stimulation (EFS) in a concentration-dependent fashion (-log EC50 was 6.60 +/- 0.10 M and maximum inhibition was 88.7 +/- 2.9%). PGE1 (greater than 0.3 microM) also reduced the contraction induced by substance P (1 microM). Removal of epithelium did not alter the effects of PGE1 on NANC contraction. These results suggest that PGE1 exerts both pre- and post-junctional inhibitory actions on NANC contraction.

Alprostadil↗
PubMed1990

Duration of pressure overload alters regression of coronary circulation abnormalities.

Using a rat model of ascending aortic banding and debanding, we examined how the duration of pressure overload affects reversibility in coronary circulation abnormalities after relief of pressure overload. Four-week banding increased left ventricular dry weight-to-body weight ratio to 158 +/- 8% of that of sham-operated controls. In isolated nonworking hearts perfused with crystalloid solution, peak mean coronary flow rate (CFR) was measured after brief ischemia. CFR and CFR/dry tissue weight significantly decreased (75 +/- 5 and 54 +/- 3% of that of controls at 100 mmHg of coronary perfusion pressure; 75 +/- 5 and 54 +/- 4% at 150 mmHg, respectively). Four weeks after debanding was performed, CFR and CFR/dry tissue weight increased to similar levels in controls. On the other hand, 10-wk banding produced the same degree of myocardial hypertrophy and decreases in CFR and CFR/dry tissue weight as in 4-wk banded rats. Four weeks after debanding was performed, CFR had not changed. CFR/dry tissue weight increased because of regression of myocardial hypertrophy but was significantly lower than that in rats debanded after 4 wk of banding. Thus the duration of pressure overload does not affect the degree of coronary circulation abnormalities in the progression process but does affect it in the regression process.

Animals↗