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M Mishima

Publications and source records attributed to M Mishima.

At least 73 records · Page 4Linked to original sources
PubMed1998

Comparison of different computed tomography scanning methods for quantifying emphysema.

Computed tomography (CT) is used to detect emphysematous changes in the lungs of living patients. It is therefore important to develop a standard method for the radiographic quantification of emphysematous lesions using CT. The authors determine the best CT scanning methods for assessing the degree of pulmonary emphysema. Computed tomography scanning was performed in 85 consecutive patients with stable chronic obstructive pulmonary disease. Scans were obtained using 2-mm or 5-mm collimation, at full inspiration or full expiration, and with standard or high spatial-resolution reconstruction images (eight images each). Emphysema was then assessed by visual scoring using a five-point scale for each lung. Emphysema was scored as significantly less severe using standard reconstruction images. There were no significant differences in CT-scored emphysema on scans obtained with 2-mm and 5-mm collimation. Emphysema was scored as significantly less severe on expiratory scans. The postbronchodilator forced expiratory volume in one second value correlated better with emphysema scored on expiratory scans. Computed tomography-scored emphysema obtained by all methods correlated well with the diffusion capacity and total lung capacity, regardless of the method used. Using a visual scoring system with a five-point scale, narrow collimation is probably not necessary for the quantification of emphysema, although a high spatial-resolution reconstruction appears to be of value. Scans obtained in exhalation appear to underemphasize the severity of emphysema.

Aged↗
PubMed1998

[Intrapulmonary arterial injection of Albunex for left heart contrast echocardiography].

Contrast enhancement of the left heart cavity and myocardium were assessed after venous injection of the ultrasound contrast agent Albunex. Myocardial perfusion was also assessed using a drug stress and image analyzing system. The study population consisted of 46 patients with normal cardiac function and without coronary artery disease, and 38 patients with effort angina. Contrast echocardiography was performed by imaging the parasternal or apical long-axis view during pulmonary arterial injection of Albunex through a Swan-Ganz catheter. Contrast enhancement in the left ventricular cavity and ascending aorta were visually assessed. Hemodynamic, arterial blood gas and electrocardiography changes were recorded before and after the injection of Albunex. Contrast echocardiography was performed before and during intravenous infusion of dipyridamole to assess left ventricular myocardial enhancement by both visual inspection and peak background-subtracted gray level using an image analyzing system. Doppler flow signal change after the injection of Albunex was assessed in 26 patients using a Doppler guide wire located in the left anterior descending coronary artery. Good contrast enhancement was obtained in all patients in the left ventricular cavity and in 17% of patients in the ascending aorta. No significant changes were observed in hemodynamics, electrocardiograms and aortic gas analysis. Significant myocardial enhancement was not seen in any patient but gray level analysis of the echo images during dipyridamole infusion showed significant enhancement in 25% of the patients without coronary artery disease and in 34% of the patients with effort angina. Doppler flow signal in the coronary artery was significantly augmented in all patients after injection of Albunex and suggests that ultrasound contrast agent reaches coronary arteries in all patients regardless of myocardial contrast enhancement. Contrast echocardiography with pulmonary arterial injection of Albunex is safe and useful to obtain sufficient left ventricular contrast enhancement. For myocardial perfusion assessment, further refinement of the ultrasound contrast agent and echo equipment is necessary.

Adult↗
PubMed1998

[Apical filling abnormality in patients with heart failure assessed with contrast echocardiography using venous injection of Albunex].

Contrast echocardiography by venous injection of Albunex was used to visualize apical filling abnormality in patients with heart failure. 1. Contrast echocardiography was serially performed in 24 patients with acute anterior myocardial infarction. Wall motion of the infarct region was better at any stage in patients without apical filling abnormality than in patients with that. Improvement of filling abnormality was observed prior to that of wall motion abnormality. 2. Influence of tachycardia was assessed on apical filling in 20 patients with old myocardial infarction during rapid atrial pacing. Stress contrast echocardiography evidenced that tachycardia deteriorates apical filling abnormality in patients with chronic heart failure. 3. The effect of amrinone on apical filling was assessed in 60 patients with chronic anterior myocardial infarction. Apical filling abnormality improved in 46% of patients after amrinone infusion. The improvement of apical filling abnormality was closely related to the reduction of preload and improvement of asynergy in the infarct area after amrinone. Both adjunctive therapy and anticoagulant therapy should be considered if apical filling abnormalities are observed by contrast echocardiography.

Albumins↗
PubMed1997

The effect of the level of ventilatory assist on the level of respiratory drive in decerebrate cats.

The present study was undertaken to investigate whether, independent of changes in PaCO2, ventilatory assist influences not only the pattern but also the level of the respiratory drive. The experiments were performed on decerebrate and paralyzed cats ventilated by a phrenic-driven servo respirator at three different FICO2 levels (0, 0.30, 0.05). The level of ventilatory assist was altered within the range where PaCO2 did not exceed 80 Torr. A higher FICO2 accompanied a higher level of ventilatory assist. The relationship between the minute phrenic activity and log10 PaCO2 at a given FICO2 was linear. No significant difference was found in the regression lines at different levels of FICO2. We conclude that ventilatory assist has little effect on the respiratory drive at a constant level of chemical feedback during hypercapnia.

Animals↗
PubMed1997

Treatment of node-positive endometrial cancer with complete node dissection, chemotherapy and radiation therapy.

We assessed the therapeutic significance of systematic aortic and pelvic lymphadenectomy followed by adjuvant therapy in node-positive endometrial carcinoma. Among 173 stage I-III patients, 30 (17%) had positive nodes: ten in the pelvic region alone (group P) and 20 in the aortic region alone or in both regions (group A). The adjuvant therapy was administered as follows: subjects in group P received 50 Gy pelvic radiation, including three post-surgical T3 (pT3) patients who received either one or three cycles of cisplatin-based chemotherapy before radiation. Subjects in group A were given three cycles of chemotherapy followed by 50 Gy pelvic and 50 Gy extended field periaortic radiation using a four-field or conformational technique. Five-year survival was 95% for 143 patients with negative nodes and 84% for 30 patients with positive nodes (100% for group P and 75% for group A). In group A, 5-year survival was 38% for eight patients with both pT3 and histology other than endometrioid type G1, and 91% for the remaining 12 patients. Either way, both group P and group A patients had a better prognosis than previously reported. In summary, aortic and pelvic lymphadenectomy and subsequent chemotherapy and radiation therapy based on node status seem to improve the survival of endometrial cancer patients with positive nodes.

Adenocarcinoma, Clear Cell↗
PubMed1997

Absorption, distribution, metabolism and excretion of a new, 14C-labelled oxazolidinone MAO-A inhibitor in rat and dog.

1. After oral administration of 14C-labelled (5R)-3-[2-((1S)-3-cyano-1-hydroxypropyl)benzothiazol-6-yl]-5-metho xymethyl -2-oxazolidinone (E2011) at a dose of 1 mg/kg, the blood level of radioactivity reached a maximum concentration (Cmax) of 0.545 microgram eq./ml after 0.25 h in the rat and of 0.900 microgram eq./ml after 0.5 h in the dog. In dog plasma, Cmax for radioactivity and unchanged E2011 were 0.862 microgram eq./ml and 0.650 microgram/ml respectively with corresponding Tmax (time at Cmax) of 0.75 and 0.25 h. The unchanged drug in dog plasma was below the detection limit (5 ng/ml plasma) after 24 h. 2. The tissue levels of radioactivity were measured at 0.25 (Tmax), 6, 24, and 168 h after administration to the rat and at 0.5 (Tmax), 24, and 168 h in the dog. The radioactivity was distributed in all tissues examined at Tmax in the rat and dog. The radioactivity levels of the cerebral cortex in the rat and dog were 26 and 36% of the plasma level at Tmax. The radioactivity in tissues decreased at almost the same rate as that in plasma. Plasma protein binding of the unchanged drug in the rat in vitro were about 70% in the range of 0.1-10 micrograms/ml, and those in the dog were about 45% in the same concentration range. 3. Cumulative excretion of radioactivity in the rat was 74.5% in urine and 22.5% in faeces after 7 days. In the dog, 55.5 and 36.5% of the radioactivity administered were excreted in urine and faeces respectively after 7 days. The biliary excretion of radioactivity in the cannulated rat was 23.0% within 48 h. 4. In tlc analysis of plasma and tissues of the rat and dog, the radioactivity for the unchanged drug was much higher than metabolites. In tlc analysis of urine, the same metabolites were detected in the rat and dog, and the radioactivity of a metabolite, IM1, was the highest in the both animals. Eight metabolites were detected in the plasma, tissues and excreta of the rat, and four metabolites in the dog. 5. In conclusion, the absorption, distribution, metabolism and excretion of 14C-labelled E2011 in the rat and dog have been established, and only minor differences were observed between these species.

Absorption↗
PubMed1997

Identification of the metabolites of a new oxazolidinone MAO-A inhibitor in rat.

1. Six metabolites present in rat urine after the oral administration of E2011 ((5R)-3-[2-((1S)-3-cyano-1-hydroxypropyl)benzothiazol-6-yl]-5-meth oxymethyl-2- oxazolidinone) were isolated with an Amberlite XAD-4 column and hplc, and termed HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4. 2. To determine the correspondence of the findings of the metabolites between tlc (which was used in our previous study) and hplc, the six metabolites were isolated from rat urine after the administration of 14C-labelled E2011 with an Amberlite XAD-4 column and hplc, and then analysed by tlc. HPM-1, HPM-2, HPM-31, HPM-32, HPM-33 and HPM-4 were identified as IM7, IM3, IM4, IM2, IM1 and E2011, respectively. 3. The structures of the metabolites were identified with nmr and mass spectrometry. One of the compounds identified, HPM-4, was the unchanged drug, E2011, and HPM-2 was O-desmethyl-E2011. Another metabolite (HPM-33), the main metabolite in the urine, was identified as (4S)-hydroxy-E2011, and the others were (4S)-hydroxy-O-desmethyl-E2011 (HPM-1), 2"-hydroxy-E2011 (HPM-31) and (4R)-hydroxy-E2011 (HPM-32). 4. In conclusion, the main metabolic pathway of E2011 in the rat consisted of O-demethylation and hydroxylation.

Animals↗
PubMed1997

Utility of a rectal suppository containing the antiepileptic drug zonisamide.

A suppository of zonisamide (ZNS) was investigated from the viewpoint of pharmaceutical evaluation, pharmacokinetics and pharmacological effect. Two types of ZNS suppositories were prepared. One used Witepsol (H-15:S-55 = 3:1) as a lipophilic base and the other polyethylene glycol (PEG, 4000:1500 = 4:1) as a hydrophilic base. The in vitro release rate of ZNS from the PEG suppository was significantly rapid compared with that of ZNS from Witepsol. Male Wistar rats were administered ZNS (20 mg/kg) using an intravenous, oral or rectal (PEG or Witepsol) route. The absorption of ZNS from the PEG suppository was more rapid than that of ZNS from the Witepsol suppository or from the oral preparation. The peak plasma concentration (Cmax) after a rectal administration of ZNS with Witepsol or PEG suppository was significantly higher than that after the oral administration of ZNS. However, the bioavailability of the three preparations was approximately 100%. Male ICR mice were administered ZNS (80 mg/kg) using the oral or rectal (PEG or Witepsol) route. A positive correlation was observed between the electroshock seizure (ES) threshold and ZNS concentration in plasma or brain. Further, there was no significant difference in the ES threshold or the ZNS concentration in plasma or brain among the three preparations. These results indicate that a ZNS suppository is a very useful preparation from the viewpoint of both pharmacokinetics and pharmacological action.

Administration, Oral↗
PubMed1997

Hypoxic ventilatory response and breathlessness following hypocapnic and isocapnic hyperventilation.

STUDY OBJECTIVES: To investigate the etiology of posthyperventilation (post-HV) hypoxemia following voluntary hyperventilation (VHV), we examined the effects of hypocapnic (hypo-CO2) and isocapnic (iso-CO2) VHV on the hypoxic ventilatory response (O2-response) and on the sensation of breathlessness during the O2-response. METHODS: O2-responses and visual analog scale (VAS) scores for estimating breathlessness in 10 normal subjects during the O2-response under iso-CO2 conditions and under hypo-CO2 conditions immediately following voluntary maximal HV of 3 min duration were examined. RESULTS: Although there was no significant difference in the post-HV ventilation levels following hypo-CO2 vs iso-CO2 VHV, the VAS scores at the start of the O2-response following hypo-CO2 VHV (30.2+/-24.2 mm) were significantly higher (p<0.05) than the VAS scores at the start of the O2-response following iso-CO2 VHV (13.7+/-8.4 mm). However, VHV did not have a significant effect on the O2-response at 2 min after the VHV when the arterial O2 saturation (SaO2) was below 90%. The nonsteady-state hypo-CO2 induced by VHV greatly attenuated the O2-response below 90% SaO2 and VAS scores at 70% SaO2. CONCLUSIONS: Elevated VAS scores immediately following the hypo-CO2 VHV, which might be independent of actual breathing levels, and the attenuation of the O2-response following the hypo-CO2 VHV were not due to input from lung and chest wall mechanoreceptors induced by the hyperpnea itself, but rather to the hypo-CO2 induced by hyperpnea.

Adult↗
PubMed1997

Ventilatory responses and subjective sensations during arm exercise and hypercapnia in patients with lower-cervical and upper-thoracic spinal cord injuries.

We measured the ventilatory responses and subjective sensations during arm exercise in patients with lower cervical and upper thoracic spinal cord injuries in order to evaluate the effects of chest wall deafferentation on these responses. Visual analog scales with verbal descriptors were used to quantify respiratory sensations of different affectional qualities. Patients as well as normal subjects reported stronger respiratory sensations upon CO2 rebreathing as compared to during arm exercise with an equivalent minute ventilation (p<0.05). There were no qualitative nor quantitative differences in the respiratory sensations during CO2 rebreathing between the patients and normal subjects. However, patients with spinal cord injuries showed a higher minute ventilation and a lower end-tidal PCO2 during incremental arm exercises (p<0.01), and thus tended to hyperventilate. We conclude that chest wall afferent denervation does not contribute significantly to the perception of breathlessness in patients with spinal cord injuries.

Adult↗
PubMed1997

Effects of resistive load on the phase difference between chest and mouth flow in patients with chronic obstructive pulmonary disease.

The influence of the resistive load on the phase difference (PD) between chest wall and mouth flow in patients with chronic obstructive pulmonary disease (COPD) was investigated, and the factors that induce an enlargement of the PD were assessed. After a resistance tube (R = 2.8 hPa/l/s) was applied to the mouth of the subjects, the PDs increased significantly both in normal (pre: 2.20 +/- 0.89, post: 5.60 +/- 2.04, P < 0.01) and in COPD (pre: 10.86 +/- 3.81; post: 13.12 +/- 3.64, P < 0.01). A significant correlation between the airway resistance and PD was noted (r = 0.730, P < 0.001). These results suggest that airway resistance is an important determinant for the PD. The predicted phase difference (PD') was then calculated by the Runge-Kutta method, using the measured chest flow, the time domain functions of airway resistance and the thoracic gas volume during a respiratory cycle, assuming that the respiratory system was a single compartment. The PD/PD' at pre-resistive load was significantly larger in COPD than in normal subjects (normal: 1.03 +/- 0.11; COPD, 1.45 +/- 0.19, P < 0.01), whereas the PD/PD' at a post-resistive load was significantly smaller than at the pre-resistive load in COPD patients. These results agree well with the two parallel or serial compartment model with inhomogeneous airway resistance, where the mechanical property of the partitioning tissue between the two compartments was taken into account. The pattern of the increase in the work energy consumed within the airway lumen calculated from this model was almost the same as for PD. Thus, we conclude that the PD may be a good index of the overload of the respiratory movement and available to predict muscle fatigue in COPD patients.

Adult↗
PubMed1997

Quantitative assessment of the spatial distribution of low attenuation areas on X-ray CT using texture analysis in patients with chronic pulmonary emphysema.

An automated and quantitative assessment of the spatial distribution of low attenuation areas (LAA) on X-ray CT was performed using texture analysis in chronic pulmonary emphysema (CPE) patients. LAA was defined as those areas having a density less than the mean minus one SD of the control (-960 HU). The probability of change from non-LAA to LAA between a given pair of pixels with horizontal intervals of i pixels (RNi) was evaluated, because this reflects the interaction between LAA and non-LAA regions with different resolutions. The relationship between the percentage area of the LAA over the total area of the entire lung field (LAA%) was subsequently estimated. The RNi increased sharply as the i value increased from 1 to 5, but then almost became a plateau for i values larger than 5. This suggests that the fundamental structures in the LAA areas ranged from 1 x 1 to 5 x 5 pixels in size. RN1-LAA% and RN5-LAA% plots produced curves which were convex, with peak values at approximately 50 LAA% of 0.09 and 0.18, respectively. In the RN5/RN1-LAA% plot, the RN5/RN1 ratio remained constant at 2.0 regardless of the LAA%. A random process simulation was performed to determine the patterns of LAA proliferation if the spatial distribution of the LAA units was random. When the unit size was kept constant, the results of the simulation did not fit the empirical relationship between the LAA% and the three parameters (RN1, RN5 and RN5/RN1). The simulation provided the best-fitting curves when the unit size of the LAA increased in proportion with the LAA%, starting from a 1 x 1 pixel size increasing at a ratio 1 x 1/(5 LAA%). This suggested that the LAA units do not proliferate randomly in spatial orientation at a fixed unit size, but rather spread throughout the whole lung field in a congregated form whilst increasing their unit size. Thus, it may be concluded that healthy lung tissues near emphysematous lesions have a high probability of suffering from emphysema in the future. This may be due to a direct effect of the neighboring emphysematous lesion or due to a pathologic change in the larger bronchii which dominate both the healthy tissues and the emphysematous lesions.

Aged↗
PubMed1997

Standardization of low attenuation area versus total lung area in chest X-ray CT as an indicator of chronic pulmonary emphysema.

We examined the methods for measuring the LAA% (100 x low attenuation area/total lung area) on thoracic X-ray CT scans in order to develop a useful indicator of chronic pulmonary emphysema (CPE). First, we modified the method for calculating the LAA% to be applicable by the programming tool installed in a commercially available CT machine in order to minimize manual procedures. This new method proved to be applicable in all CT machines produced after 1987. Second, we examined the difference in the Hounsfield Unit (HU) between different CT machines using two kinds of phantoms. One phantom was composed of Styrofoam, which has a density similar to the low attenuation areas. The other phantom was composed of Styrofoam and water, which has a density similar to the lung. We proved that the difference of LAA% with the correct value was 5% at maximum among four different CT machines. Thus, the phantom developed in the present study may play an important role in the standardization of HU. Finally, the possibility of decreasing the X-ray levels was examined. Twenty-five percent of the standard electrical current provided the same LAA% in cases where the subject was an established CPE patient, whereas the LAA% was overestimated in subjects with a normal LAA% value. However, a correction using a linear regression equation may be possible in the latter cases. It may be concluded that LAA% analysis can easily be performed in many city hospital, without much investment of manual procedures or any corrections to the HU levels between different CT machines. This method may be useful as a routine follow up for CPE patients because of the smaller irradiated dose given when using a CT machine.

Algorithms↗
PubMed1996

Temporal response of lung impedance after i.v. oleic acid in dogs.

We measured total and regional lung impedances in six anaesthetized, paralysed dogs every min for 1 hour immediately following i.v. oleic acid administration. Total lung impedance was assessed from pressure and flow data collected at the airway opening during conventional mechanical ventilation. We obtained regional lung impedance at two sites simultaneously using our recently developed alveolar capsule oscillator technique (Davey, B.L.K. and J.H.T. Bates, 1993, Respir. Physiol. 91:165-182). We found that total lung resistance (RL) increased for the first 15 min in a manner suggestive of an initial bronchoconstrictive event, and then remained stable for the remainder of the hour. EL continued to increase throughout the entire period. In contrast, regional alveolar resistance (RA) increased initially and then returned to baseline, while regional alveolar elastance (EA) remained unchanged. We interpret these results as reflecting an initial transient bronchoconstriction together with a progressive accumulation of oedema in the dependent regions of the lung. This implies that the changes in EL were due mostly to increased heterogeneity of regional ventilation, and that non-dependent lung regions may remain virtually unaffected mechanically even when the overall oedematous changes in lung mechanics are severe.

Airway Resistance↗
PubMed1996

Collateral channels that develop after an acute myocardial infarction prevent subsequent left ventricular dilation.

OBJECTIVES: We sought to evaluate the effect of collateral channels that develop late after a first anterior myocardial infarction on left ventricular dilation and function. BACKGROUND: Collateral channels in an infarct-related artery may develop long after occlusion of the artery. Well visualized collateral channels that appear immediately after a myocardial infarction reduce infarct size and preserve left ventricular function. However, the functional significance of collateral channels that develop late after myocardial infarction has not been evaluated in terms of left ventricular function. METHODS: We studied 21 patients with a first anterior myocardial infarction and an infarct-related artery that remained totally occluded after reperfusion therapy and did not reopen within 1 month of infarction. No collateral channels were observed during the acute period. Patients were classified into two groups according to the extend of collateral formation 1 month after infarction: group C, patients with well developed collateral channels (n = 11), and group NC, patients with absent or poorly developed collateral channels (n = 10). Infarct size was determined by peak creatine kinase activity and thallium-201 single-photon emission computed tomography. Global and regional left ventricular function and left ventricular volumes were assessed by left ventriculography. These measurements were identical in both groups 1 month after infarction. Left ventricular function was reevaluated after 2.12 +/- 0.79 years (mean +/- SD). RESULTS: There were no significant changes in global and regional left ventricular function between the two groups during the long-term follow-up period. However, the end-diastolic volume index of group NC increased from 71 +/- 14 to 85 +/- 19 ml/m2, whereas that of group C decreased from 64 +/- 18 to 59 +/- 12 ml/m2. This important change during the long-term follow-up period resulted in a significant difference (p = 0.0006) in the end-diastolic volume index between the groups 2 years after onset (p = 0.002), whereas 1 month after infarction the difference was not significant (p = 0.36). A similar pattern was observed for the end-systolic volume index (group C: 38 +/- 16 to 35 +/- 14 ml/m2; group NC: 45 +/- 12 to 58 +/- 18 ml/m2, p = 0.018). The power of the tests to detect the observed differences showing nonsignificant results ranged from 0.05 to 0.38, whereas the power of the tests indicating a significant difference in end-diastolic and end-systolic volume indexes was >0.88. CONCLUSIONS: Collateral channels that develop after a myocardial infarction do not reduce the infarct size or prevent left ventricular dilation within 1 month of infarction. In contrast, such collateral channels prevent subsequent ventricular dilation and the deterioration of left ventricular function over 2 years. However, our results may have been biased because of the small number of patients.

Aged↗
PubMed1996

Influence of baseline airway calibre and pulmonary emphysema on bronchial responsiveness in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: Bronchial hyper-responsiveness (BHR) is widely observed in patients with chronic obstructive pulmonary disease (COPD). However, its clinical significance in COPD has not yet been established. To determine the factors that influence BHR in COPD, multiple linear regression analysis was used to analyse the relationship between BHR to methacholine and baseline forced expiratory volume in 1 s (FEV1), vital capacity (VC), residual volume (RV)/total lung capacity (TLC), static compliance (Cst), transfer coefficient of the lung (Kco), and the percentage of low attenuation area (%LAA) determined by computed tomographic (CT) scan. METHODS: Bronchial responsiveness to methacholine was determined in 63 patients with COPD by the dosimeter method and expressed as PD20FEV1. Residual volume and TLC were determined by body plethysmography. The percentage of low attenuation area was defined as the percentage of area less than -960 Hounsfield unit on a CT scan of the thorax. RESULTS: Forced expiratory volume in 1s (%predicted) and %LAA correlated with BHR (P = 0.023 and 0.020, respectively), while VC (%pred), RV/TLC, Cst and Kco did not. The coefficient of determination was 0.43. The regression analysis showed that a 10% increase in FEV1 (%pred) and a 10% decrease in %LAA would increase log(PD20FEV1) by 0.145 and 0.117, respectively. CONCLUSIONS: A considerable proportion of the BHR in COPD is related to functional abnormalities and morphologic changes of emphysema, such as decreased baseline airway calibre and destruction of the lung parenchyma.

Aged↗