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Biomedical subjects

T Takishima

Publications and source records attributed to T Takishima.

At least 73 records · Page 4Linked to original sources
PubMed1994

Oxygen consumption of respiratory muscles in patients with COPD.

We measured the oxygen consumption (VO2) of respiratory muscles in 8 COPD patients and 12 age-matched healthy subjects using a closed circuit device which allows a continuous increase in external dead space and is equipped with a 9-L Collins spirometer. Furthermore, we measured simultaneously mouth occlusion pressure at 0.1 s of inspiration (P0.1), minute ventilation (VE), and other ventilatory parameters during the measurement of total VO2 (VO2 tot). We found that the logarithm of VO2tot (logVO2tot) had a good correlation with VE in both groups. The mean slope of the regression line of logVO2tot and VE (delta logVO2tot/delta VE) of COPD patients was significantly higher than that of normal subjects (p < 0.001). However, the mean Y-intercept (metabolic VO2[VO2met]) of the regression lines did not differ between the two groups. The P0.1 in COPD patients was higher than that in normal subjects at the corresponding dead space loading. However, the VE did not differ between the two groups except for at rest and the first 1 min after dead space loading. These results suggest that the VO2 of respiratory muscles in patients with COPD is higher at given ventilation compared with that in age-matched normal subjects and that this increased VO2 partly may be due to an augmented ventilatory drive.

Aged↗
PubMed1994

Intrapleural omentum simulating pleural effusion.

We report herein a case of Morgagni hernia of omentum into the pleural space, simulating a pleural effusion on a routine chest radiograph. A 62-year-old man was referred to our clinic for close examination of a pleural effusion-like shadow at the right costophrenic region. He had no history of trauma and no symptoms. Chest computed tomographic scan showed a pleural effusion-like shadow with a fat density. Thoracoscopy revealed a movable omentum-like mass and no significant fluid in the right pleural space. Magnetic resonance imaging and celiac angiography confirmed the herniation of omentum into the right pleural space. This case suggests that a Morgagni hernia must be excluded in a patient with a fat density effusion-like shadow in the pleural space.

Diagnosis, Differential↗
PubMed1994

Upper airway muscle activity during REM and non-REM sleep of patients with obstructive apnea.

We measured electromyograms (EMGs) of genioglossus muscle (GG) and inspiratory intercostal muscle (IIM) in both rapid eye movement (REM) sleep and non-REM sleep of 12 patients with obstructive sleep apnea (OSA) to examine the influence of different sleep stages on upper airway muscle activity during sleep apnea. Quantifications of both muscle activities were assessed by their individual peak amplitude of integrated inspiratory EMG. Genioglossus and IIM activities showed a qualitatively similar cyclic change with an alteration of apneic and ventilatory phases during both non-REM and REM sleep. Both muscle activities increased gradually in the late apneic phase and reached each peak at the opening of the upper airway and, subsequently, decreased gradually. There were no significant differences in both muscles activities in either the ventilatory or early apneic phase between non-REM sleep and REM sleep. On the other hand, GG and IIM activities in the late apneic phase during REM sleep were significantly lower than those during non-REM sleep. The relative activity of GG to IIM in the late apneic phase was significantly lower during REM sleep than that during non-REM sleep. These results indicate that upper airway and intercostal muscle activation in the later apneic phase during REM sleep were inhibited compared with those during non-REM sleep and that this inhibition was observed predominantly in upper airway muscles.

Adult↗
PubMed1994

Responses to hemodynamic stress in the aged heart.

In aged individuals the incidence of heart failure is higher than in younger subjects. Ischemic events are also common in the aged heart because of changes in the coronary vasculature and myocytes caused by aging. Adaptational responses to increased hemodynamic overload and to ischemia in the aged heart are discussed at the molecular, cellular and organ levels. One characteristic of the aged heart is a limited capacity for adaptation with hypertrophy to increased mechanical load. This age-related attenuation of the hypertrophic response may be attributed to the diminished induction of proto-oncogenes such as c-fos, c-myc and c-jun by hemodynamic stress. This diminution results from the aging of the heart per se and may be modulated by extracardiac factors. An age-related diminution was also observed in the mRNA induction of heat shock proteins by transient ischemia. However, this diminished induction of immediate early genes in the aged heart was not observed after more severe stress. With regard to the coronary vasculature, the age at which pressure-overload begins seems to be one of the important factors which determine the vascularity of hypertrophied hearts. Late-onset pressure-overload decreased dilator reserve in spite of the absence of myocardial hypertrophy. Thus, the responses to stress in the aged heart are quite different from those in the young heart. The limited capacity for adaptation to hemodynamic overload and poor protective mechanisms against stress may be causes of the higher incidence of heart failure in the aged.

Aged↗
PubMed1994

Effects of unilateral phrenic nerve denervation on diaphragm contractility in rat.

We examined the early effects of phrenic nerve denervation on the diaphragm muscle 1, 3, 7 and 14 days after unilateral denervation in rats. In the denervated hemidiaphragms, force frequency curves at 3, 7 and 14 days decreased significantly by 51%, 50% and 38% respectively of the peak tension of the force frequency curves of the diaphragms of rats with sham operation. Twitch tensions increased significantly at 14 days, and contraction times and half relaxation times slowed significantly at 3, 7 and 14 days. The tensions of denervated diaphragms at 5 min during the fatigue runs was significantly increased at 14 days. As determined by histological staining, the mean cross sectional area of fast-twitch fibers (type II) decreased significantly from 2,742 (sham) to 1,599 microns (14 days), but that of the slow-twitch fibers (type I) did not change significantly during the same period. These findings suggest that, during the first two weeks of denervation, fast twitch fibers (type II) atrophy more rapidly than slow twitch fatigue resistant fibers (type I), as confirmed by the contractile properties and histological findings.

Adenosine Triphosphatases↗
PubMed1994

Bronchoalveolar lavage as a possible cause of acute exacerbation in idiopathic pulmonary fibrosis patients.

In the past 13 years (1980 to 1992), bronchoalveolar lavage (BAL) was performed on 124 idiopathic pulmonary fibrosis (IPF) patients (29 F and 95 M, 60 +/- 1 years, mean +/- S.E.) at Tohoku University Clinic and Hospital. Among them, three patients showed acute exacerbation immediately after BAL and died of progressive respiratory failure after 2.5 weeks, 2 months and 3.5 months, respectively, despite intensive care. They were all older patients (79, 74 and 66 years old) and we failed to find any evidence of viral, bacterial or fungus infections either before or after BAL in blood, sputum or BAL fluid samples. Further, all autopsied lungs showed interstitial pneumonia and fibrosis and no evidence of infectious diseases. In contrast, no progressive deteriorations after BAL were observed in 282 patients (122 F and 160 M, 48 +/- 1 years old) with other pulmonary diseases (sarcoidosis, bronchial asthma, collagen diseases and other interstitial lung diseases), who received BAL during the same period. This suggests that BAL itself sometimes induces a progressive degeneration in IPF patients, especially in older patients.

Aged↗
PubMed1994

Mechanically assisted intraoperative peritoneal lavage for generalized peritonitis as a result of perforation of the upper part of the gastrointestinal tract.

BACKGROUND: The efficiency of intraoperative peritoneal lavage (IOPL) and peritoneal drainage in patients with generalized peritonitis remains controversial. The benefit of large volume IOPL, using a newly designed device, and of peritoneal drainage were evaluated in 101 patients with generalized peritonitis. STUDY DESIGN: Patients were divided into two groups, one treated by mechanically assisted IOPL (group 1), and the other treated by manual IOPL (group 2). They were further divided into two groups, one undergoing drainage (DR group) and the other undergoing no drainage (ND group). Based on data in the progress notes, patients in these groups were compared with each other with respect to disease process, volume of IOPL fluid, incidence of infectious complications, and other prognostic factors. RESULTS: In group 1, the incidence of infectious complications was significantly lower than in group 2 (10.8 versus 62.9 percent, p < 0.01). Patients who underwent operative treatment 12 hours or more after onset of peritonitis had a lower incidence of infection following high volume IOPL (greater than or equal to 30 L) compared with those patients who underwent low volume IOPL. The incidence of infectious complications was significantly higher in the DR group (32.8 versus 12.9 percent). CONCLUSIONS: A large volume of saline (greater than or equal to 30 L) was needed for IOPL. The new device for IOPL proved to be very successful and efficient. When IOPL was successful, it seemed that peritoneal drainage did not provide any additional benefits to the treatment of generalized peritonitis.

Adolescent↗
PubMed1993

Coronary dilator reserve and morphological changes after relief of pressure-overload in rats.

Using a rat model of short- (4 weeks) and long-term (10 weeks) ascending aortic banding and debanding, we examined the relationship between coronary dilator reserve and morphological vascular changes. After 4 or 10-week banding, in vivo systolic left ventricular pressure and ventricular wt/body wt ratio increased to a similar level, compared with controls. The coronary dilator reserve measured in an isolated heart preparation decreased similarly in the two banded groups, compared with controls. The ratios of medial to luminal area and perivascular collagen to luminal area in coronary microvessels increased in the banded groups. At 4 weeks after debanding, cardiac hypertrophy regressed to the control level, and the duration of banding did not alter the extent of the regression. The coronary dilator reserve normalized in the group debanded after 4-week banding, but did not regress in the group debanded after 10-week banding. In both of the debanded groups, the hypertrophied media regressed completely. The increased perivascular collagen regressed almost completely in the group debanded after 4-week banding, but remained greater in the group debanded after 10-week banding than in the controls. From these results, we conclude that (i) the regression of medial hypertrophy does not always improve the decreased coronary dilator reserve, and (ii) the vascular fibrosis may be the major cause of the irreversibility of decreased coronary dilator reserve in long-term cardiac hypertrophy.

Animals↗
PubMed1993

The source of epifluorescence in isolated perfused heart loaded with fura 2-AM or indo 1-AM.

The purpose of this study is to clarify the kinds of cells that fluoresce in isolated perfused heart intracoronarily loaded with fura 2-AM or indo 1-AM. The hearts from hamsters perfused by the Langendorff method were loaded with fura 2-AM or indo 1-AM intracoronarily. The epicardium was excited by ultraviolet light at a wavelength of 340 or 380 nm (fura 2) or 360 nm (indo 1). Epifluorescent images from arrested hearts prepared with St Thomas' cardioplegic solution were observed through an inverted microscope and taken by a still camera. Endothelial cells and pericytes of the capillaries showed intense fluorescence. In the intercapillary spaces, a less intense but still apparent fluorescence emitted by myocytes could also be detected. On the other hand, fluorescence from smooth muscle cells and fibroblasts could not be identified. Therefore, epifluorescence in the isolated perfused heart loaded with fura 2-AM or indo 1-AM was mainly generated within endothelial cells, pericytes, and myocytes. To evaluate calcium fluorescence in isolated hearts quantitatively, the fluorescence of endothelial cells and pericytes of the capillaries must be taken into consideration.

Animals↗
PubMed1993

A 5-lipoxygenase inhibitor, FR110302, inhibits ozone-induced airway hyperresponsiveness in guinea pigs and dogs.

Airway hyperresponsiveness is a key feature of asthma, and attenuating airway hyperresponsiveness is an important part of asthma therapy. In the present study we examined the inhibitory effect of a potent 5-lipoxygenase inhibitor, FR110302, on airway hyperresponsiveness induced by ozone exposure in guinea pigs and dogs. Respiratory resistance (Rrs) was measured by a forced oscillation method. Airway responsiveness was determined from the dose-response curve of Rrs to acetylcholine. Guinea pigs were exposed to 2.5 ppm ozone for 1 h. In a control group of guinea pigs, delta log PC100 (the index of the ozone-induced airway hyperresponsiveness) was 0.58 +/- 0.04 (log mg/ml). Treatment with FR110302 (10 or 100 mg/kg p.o.) significantly diminished delta log PC100 (10 mg/kg: 0.22 +/- 0.10; 100 mg/kg; 0.11 +/- 0.06). Dogs were exposed to 3 ppm ozone for 2 h. In a control group of dogs, delta log Dmin (another index of the ozone-induced airway hyperresponsiveness) was 1.24 +/- 0.15 (log unit). Treatment with FR110302 (1 or 3.2 mg/kg p.o.) significantly diminished delta log Dmin (1 mg/kg: 0.60 +/- 0.18; 3.2 mg/kg: 0.27 +/- 0.12). These results suggest that FR110302 may be a useful drug for attenuating airway hyperresponsiveness in asthmatic patients.

Acetylcholine↗
PubMed1993

Estimation of left ventricular myocardial elasticity and viscosity by a thick-walled spherical model.

The authors measured the transfer function (TF) of the left ventricle (LV) in an isolated canine preparation. Here TF indicates the ratio of induced vibration in LV to input vibration when an external mechanical oscillation is applied. TF had a single peak the frequency of which changed from 40 Hz to 80 Hz when LV pressure (LVP) increased from 6 mm Hg to 96 mm Hg. A mathematical model was formulated to estimate the viscoelasticity of the spherical shell. This model was constructed of the material points, elastic components which connected all the material points, and viscous components placed in series with elastic components. Theoretical TF can be computed if the viscoelastic values are given. The value of viscoelasticity at which the theoretical TF best fitted the experimental TF was considered to be the viscoelasticity of the model. The validity of this approach was verified using a silicone spherical shell. The estimated myocardial elasticity was 40 kPa when LVP was 6 mm Hg, 160-170 kPa when LVP was 96 mm Hg and was approximately proportional to LVP, whereas viscosity showed small change. The inclination of elasticity was consistent with previous reports. These results proved that myocardial elasticity can be estimated by analysing the transfer function of the left ventricle.

Animals↗
PubMed1993

A stimulatory role of protein kinase C in feline tracheal submucosal gland secretion.

To determine the role of protein kinase C (PKC) in airway submucosal gland secretion, we examined the effect of a selective PKC stimulant, phorbol 12-myristate 13-acetate (PMA), on mucus glycoprotein (MGP) secretion, fluid secretion and intracellular Ca2+ concentration ([Ca2+]i) in isolated feline submucosal glands. MGP and fluid secretions were estimated by measuring trichloroacetic acid (TCA)-precipitable glycoconjugates and 22Na-efflux, respectively, from isolated glands. [Ca2+]i was measured using a Ca(2+)-sensitive fluorescent dye, Fura 2. PMA itself produced a significant increase in MGP secretion in a dose-dependent fashion (173% of control at 10(-5) M). PMA also produced a significant increase in 22Na-efflux (151% of baseline rate constant at 10(-5) M). Indomethacin failed to alter the increase in MGP secretion or in 22Na-efflux in response to PMA. Two PKC inhibitors, 1-(5-isoquinolinesulfonyl)-2-methylpiperazine (H-7) and sphingosine, inhibited both MGP secretion and 22Na-efflux stimulated by PMA; there was only a partial inhibition after stimulation by methacholine (MCh). PMA did not significantly alter [Ca2+]i and H-7 did not alter the MCh-induced [Ca2+]i rise. These findings indicate that PKC has a direct stimulatory role in stimulus-secretion coupling of airway submucosal gland secretion.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1993

Surfactant apoprotein A secretion by human tracheobronchial epithelial cells.

To determine whether surfactant apoproteins are produced locally by the airway walls, we used a two-site simultaneous immunoassay with monoclonal antibodies and measured the surfactant apoprotein-A (SP-A) content in media cultured with human airway explants or cultured epithelial cells. Tracheobronchial explants were cultured for 2 successive periods (periods I and II). Significant SP-A concentrations were detected in both periods. Methacholine (MCh) or isoproterenol (ISP), added to the medium at the beginning of period II, reduced the ratio of SP-A concentration in period II to that in period I, compared to samples without treatment. The SP-A concentration in the medium at the confluent period of cultured epithelial cells was significantly higher than at the mid-period, indicating that SP-A secretion is dependent on the cell number. The supernatant from explants stimulated by MCh was capable of reducing SP-A secretion from cultured epithelial cells. Immunohistochemical study of SP-A using monoclonal antibody demonstrated positive immunoperoxidase staining in the cytoplasm of epithelial cells. Further, Western blots of electrophoresed proteins from epithelial cells showed the characteristic properties of SP-A. These findings indicate that tracheobronchial epithelium can secrete SP-A.

Apolipoproteins A↗
PubMed1993

The effect of an oral leukotriene antagonist, ONO-1078, on allergen-induced immediate bronchoconstriction in asthmatic subjects.

BACKGROUND: Cysteinyl leukotrienes are potent contractile agonists for airway smooth muscle. To examine the relative role of cysteinyl leukotrienes in immediate airway obstruction in human subjects with asthma after allergen challenge, we investigated the effect of ONO-1078, a potent receptor antagonist of cysteinyl leukotrienes, on the response. METHODS: ONO-1078 and an inactive placebo, in 150-mg capsule form, were administered every 12 hours for 1 week, in a double-blind, cross-over fashion. To examine the effect on the early part of the response, total respiratory resistance (Rrs) was continuously evaluated for 10 minutes after the start of a 1-minute exposure to an appropriate concentration of allergen. Rrs and FEV1.0 were estimated every 10 minutes for 60 minutes after the exposure. RESULTS: ONO-1078 significantly reduced percent changes in Rrs and FEV1.0 from 20 to 60 minutes after the exposure, as well as percent maximum changes in these indices, although the treatment did not alter the time from the start of allergen exposure to the beginning of elevation of Rrs, the time from the start to the point at which total respiratory conductance decreased by 35% from its baseline value, or percent changes in Rrs or FEV1.0 10 minutes after the exposure. CONCLUSIONS: Therefore, we conclude that cysteinyl leukotrienes primarily mediate a later part of immediate airway obstruction after allergen exposure.

Administration, Oral↗
PubMed1993

Effects of percutaneous transluminal mitral valvuloplasty on plasma catecholamine levels during exercise.

Elevation of plasma catecholamine levels during exercise in patients with mitral stenosis correlated with the severity of the disease. We investigated the plasma norepinephrine changes in six patients before and after percutaneous transluminal mitral valvuloplasty (PTMV) during continuously graded ergometer exercise. Peak exercise intensity was increased from 65.8 W to 87.5 W after PTMV. Plasma norepinephrine level at 60 W workload intensity was decreased from 2308 +/- 864 pg/ml to 841 +/- 233 pg/ml after PTMV (p < 0.05). We concluded that PTMV decreased the plasma norepinephrine level during exercise in the patients with mitral stenosis. Percutaneous transluminal mitral valvuloplasty is a novel procedure for the improvement of symptoms in patients with mitral stenosis.

Adult↗
PubMed1993

Effects of arterial distensibility on left ventricular ejection in the depressed contractile state.

OBJECTIVE: The aim was to evaluate the effects of arterial distensibility on ventricular ejection in various ventricular contractile states: (1) control; (2) a regionally depressed contractile state due to left circumflex coronary artery occlusion (ligation); (3) a globally depressed contractile state induced by lignocaine (lignocaine); and (4) a globally augmented contractile state due to dobutamine infusion (dobutamine). METHODS: Arterial compliance was decreased from 2.3 x 10(-4) dyne-1.cm5 (C2.3) to 0.4 x 10(-4) dyne-1.cm5 (C0.4), maintaining other afterload components and left ventricular end diastolic pressure constant. Nine excised perfused and paced canine hearts, supported from donor dogs, were used. RESULTS: In control, ligation, lignocaine, and dobutamine groups, the difference in cardiac output between the compliance values of C0.4 and C2.3 was 124(SEM 32), 204(36), 163(33), and 130(24) ml, respectively. Thus cardiac output at C0.4, as a percentage of that at C2.3, was 88(2.8)% (control), 75(2.9)% (ligation), 82(2.9)% (lignocaine), and 88(2.4)% (dobutamine), respectively: control v ligation, and lignocaine v ligation, p < 0.001; control v lignocaine, and dobutamine v ligation, p < 0.01. Stroke work at C0.4 decreased in the ligation group (63%, p < 0.001) and in the lignocaine group (70%, p < 0.001). CONCLUSIONS: When cardiac dysfunction is already present, decreased arterial distensibility has a further deleterious effect on cardiac output. This may be due to the fact that the pressure at the end of ejection is higher and as a result the change in dimension during ejection is considerably reduced, especially in cases with depressed cardiac function caused by afterload dependency.

Animals↗
PubMed1993

Continuous measurement of canine coronary blood volume change with alterations of heart rate.

OBJECTIVE: The aim was to examine the effects of heart rate on total coronary blood volume with pressure-type plethysmography in isolated and vasodilated canine hearts. METHODS: Nine hearts were excised from anaesthetised mongrel dogs (13.1-15.2 kg) and perfused with arterial blood of other dogs (17.0-29.0 kg). The venous blood returning to the right atrium and both ventricles was drained under constant negative pressure (-10 mm Hg). A thin latex balloon filled with water was inserted into the left ventricle to keep the intraventricular volume constant. The pressure difference between the cylinder into which the heart was placed and a compensation chamber was measured as a change in coronary blood volume while heart rate was altered from 120 beats.min-1 (control heart rate) to a target level (60, 90, 150, or 180 beats.min-1). RESULTS: The mean coronary blood volume change compared with that at control heart rate was 1.65(SEM 0.32) ml x 100 g-1 at 60 beats.min-1 (p < 0.005) and -0.74(0.20) ml x 100 g-1 at 180 beats.min-1 (p < 0.005) under the perfusion pressure of 70 mm Hg. The mean volume decreased with the increase in heart rate. Diastolic-systolic variations in coronary blood volume also decreased with an increase in heart rate, from 0.61(0.06) ml x 100 g-1 (60 beats.min-1) (p < 0.005) to 0.12 ml.100 g-1 (180 beats.min-1). Both mean change and variation were almost linear functions of R-R interval (r = 0.88 and r = 0.83). Lowering the perfusion pressure from 70 to 40 mm Hg diminished the changes in both mean and variation of the coronary blood volume. CONCLUSIONS: Tachycardia reduces the mean coronary blood volume and the diastolic-systolic variations in isolated vasodilated canine hearts.

Animals↗