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Biomedical subjects

O Okada

Publications and source records attributed to O Okada.

At least 55 records · Page 3Linked to original sources
PubMed1995

[Puerperal secondary pulmonary hypertension in a patient with mixed connective tissue disease].

A woman with mixed connective tissue disease (MCTD) developed pulmonary hypertension after delivery of a child, but had little evidence of parenchymal lung disease. This 29-year-old woman had been given a diagnosis of MCTD when she was 19 years old. She was admitted to our department two days after delivery of a child, because of dyspnea on exertion. Acute thromboembolism was suspected because of: (1) chest roentgenogram showing cardiomegaly and enlargement of the left main pulmonary artery, (2) a lung perfusion scan showing a segmental defect in the left S6 and S8 areas, (3) laboratory studies showing abnormally high WBC, LDH, FDP, and D-D dimer, and (4) arterial blood gas analyses showing mild hypoxemia and hypocapnia. Thrombolytic therapy with heparin and urokinase was begun, and was followed by a loop diurtic and anticoagulation with warfarin. One month after admission, cardiac enlargement and the A-aDO2 were found to have decreased. At that time, cardiac catheterization was done and revealed pulmonary hypertension (mean PA pressure: 45 mmHg) and low cardiac output with no detectable thrombosis in the left pulmonary artery. The patient was subsequently treated with a calcium antagonist and a prostacyclin derivative, and her condition was stable for 5 months. Then her exercise tolerance gradually decreased due to shortness of breath, and cardiomegaly gradually increased over the next 3 months. Eight months after delivery of the child, the patient died of right heart failure. In clinically stable patients with MCTD, delivery of a child may lead to pulmonary thromboembolism and pulmonary hypertension.

Adult↗
PubMed1995

[A case of idiopathic pulmonary arteritis with positive anti-myeloperoxidase antibodies].

A 38-year-old woman was referred to our hospital for severe pulmonary hypertension (pulmonary arterial pressure 63/36 mmHg). Digital subtraction angiography showed complete obstruction of the right main pulmonary artery and severe stenosis of the left main pulmonary artery. Although there were no symptoms or signs of systemic arterial lesions, the initial diagnosis was aortitis syndrome with pulmonary arterial involvement, and prednisolone therapy was started (60 mg/day). Pulmonary arterial pressure decreased to 53/12 mmHg. At a dosage of 20 mg/day, however, multiple nodular shadows were present on the X-ray film of the chest, but they disappeared after the dosage was increased. The level of anti-myeloperoxidase antibodies in her serum changed at almost the same time as multiple nodular shadows appeared on the chest X-ray film. Because anti-MPO antibodies have been never detected in patients with aortitis syndrome, polyangitis overlap syndrome was suspected. However, we found no evidence of systemic vasculitis; that is, vasculitis in other organs, including the kidney and the skin. Therefore, we made a diagnosis of idiopathic pulmonary arteritis with positive anti-MPO antibodies.

Adult↗
PubMed1995

[Does nocturnal hypoxia relate to acute exacerbation of chronic respiratory failure with right heart failure in late sequelae of pulmonary tuberculosis?].

Thirty-eight patients with late sequelae of pulmonary tuberculosis (TB seq.) were studied to clarify whether or not nocturnal oxyhemoglobin desaturation (NOD) could relate to acute exacerbation of chronic respiratory failure (AE). All patients had been untreated with home oxygen therapy, because they were not severely hypoxic. We performed sleep studies, pulmonary function tests and arterial blood gas analysis and investigated past history about AE in each patient. Twelve patients had experienced AE with right heart failure and they were classified as CHF (congestive heart failure) group. The rest was classified as Non-CHF group. These two groups were compared as for each variables examined. There was no difference between the two groups in age, body weight, %VC, FEV1.0%, and awake PaO2. Awake PaCO2 was significantly higher in CHF group. Although no difference was observed in baseline SaO2, the degree of NOD was significantly greater in CHF group when evaluated by lowest SaO2 during sleep and 85% desaturation time (total time spent with SaO2 less than 85%). Moreover, 21 of Non-CHF and 6 of CHF were studied for cardiac parameters using right side cardiac catherization. While the differences of mean pulmonary arterial pressure and cardiac output between the two groups were not significant, pulmonary arteriolar resistance was higher in CHF group. We concluded that NOD in TB seq. had a major role in AE with right heart failure. We speculated that AE might be caused, at least partly, by pulmonary vasopressor response to recurrent NOD.

Acute Disease↗
PubMed1995

[Daytime pulmonary hypertension in the obstructive sleep apnea syndrome].

Patients with obstructive sleep apnea syndrome (OSAS) may have daytime pulmonary hypertension (PH). Transient and sometimes severe elevations of pulmonary arterial pressure during sleep as a result of intermittent upper airway obstruction may lead to daytime PH. We sought to study the factors involved in the development of daytime PH. Right-heart catheterization, pulmonary function tests, and arterial blood gas measurements were done in 25 patients in whom OSAS was diagnosed by whole-night polysomnography. Eight of the patients (32%) had PH, defined by a mean pulmonary arterial (PA) pressure > or = 20 mmHg. For the group as a whole, mean PA pressure was positively and significantly correlated with daytime PaCO2 (r = 0.79), percent of ideal body weight (r = 0.45), and Hb (r = 0.40). Mean PA pressure was negatively and significantly correlated with PaO2 (r = -0.54), FEV 1% (r = -0.52), and %FVC (r = -0.68). In contrast, mean PA pressure was not significantly correlated with apnea index or with sleep desaturation. These data indicate that daytime PH was not directly related to sleep-disordered breathing, but was related to daytime hypoxemia, daytime hypercapnia, obesity, obstructive and restrictive respiratory impairments, and secondary polycythemia.

Adult↗
PubMed1995

[Neoadjuvant chemotherapy with continuous intra-arterial infusion (cisplatin, 5-fluorouracil) in the treatment of stage III cervical cancer].

Continuous arterial infusion therapy with a reservoir for neoadjuvant chemotherapy was used in 12 cases of cervical carcinoma, clinically progressive Stage III, to examine its usefulness. Drugs used were cisplatin, 10 mg/day (one shot) and 5-fluorouracil, 250 mg/day (continuous), which were infused from bilateral subhypogastric reservoirs to bilateral internal iliac arteries for 10 days (one course) at a rate of 2 times per 3 weeks. As a result, diminution of main lesion was observed in all cases, and radical hysterectomy could be performed on all but one of 11 patients, who refused the surgery. Histological examination of resected uteri revealed Grade III (3 cases, Grade II (6 cases), Grade I b (1 case) and Grade I a (1 case). The present therapy enabled us to obtain not only AUC of filterable platinum, comparable to 2 hour-drip infusion of cisplatin 100 mg/day, but also therapeutic effects on lymphnodal metastasis. In spite of this excellent effectiveness, slight side effects such as hemotoxicity, Grades 1 and 2, and digestive disorder, were noted. From the above, the present therapy, despite the slight side effects, can be regarded as an effective therapeutic approach which enables us not only to stage down progressive Stage-III cervical carcinoma and to indicate radical hysterectomy, but also expect an improved prognosis.

Adult↗
PubMed1995

[Wilson-Jones type angiosarcoma with marked response to intrapleural administration of interleukin-2].

A 64-year-old woman was admitted to our hospital with a hemothorax after one year of therapy for angiosarcoma that had arisen from the skin of the head. The hemothorax was believed to have resulted from metastasis of the angiosarcoma. Interleukin-2 (IL-2) at a dose of 20 x 10(4) U once daily was administered intrapleurally. Clinical improvement was first observed on the second day after the first dose of IL-2. Increases in natural and in lymphokine-activated killer activity of lymphocytes in pleural effusion were found on the eighth day. Starting on the 16th day of IL-2 therapy, no more fluid was drained, so administration of IL-2 was stopped. The clinical course indicated that the pleural effusion disappeared not because of pleurodesis but because of the anti-cancer effects of IL-2. There were no marked side effects, and intrapleural administration of IL-2 may be useful in patients with hemothorax due to metastasis of angiosarcoma.

Female↗
PubMed1994

Putative functions of phenylalanine-350 of Pseudomonas putida cytochrome P-450cam.

Cytochrome P-450cam hydroxylates d-camphor, using molecular oxygen and reducing equivalents transferred via putidaredoxin. We constructed mutant genes in which Phe-350 of P-450cam was replaced by Leu, Tyr, or His by site-directed mutagenesis, expressed them in Escherichia coli, purified the mutant proteins, and compared their enzymic properties with those of the wild type P-450cam. NADH oxidation rate of the Tyr mutant in the reconstituted system with putidaredoxin and putidaredoxin reductase was similar to that of the wild type enzyme, while the Leu mutant and the His mutant showed 67% and 17% activity of that of the wild type, respectively. The affinities of these mutant proteins for camphor and the oxidized form of putidaredoxin were much the same as those of the wild type protein. Rate constants for the reduction reaction of P-450cam by reduced putidaredoxin, a physiological electron donor for P-450cam, of Tyr and His mutants were much the same as that of the wild type enzyme, whereas the Leu mutant showed approx. half that of the wild type. Thus, the aromatic ring of Phe-350 of P-450cam probably contributes to enhancing efficiency of the electron transfer yet does not seem to be essential for the reaction.

Base Sequence↗
PubMed1994

Temporal capillary perfusion patterns in single alveolar walls of intact dogs.

Pulmonary gas exchange reserve in the form of recruitable capillaries was first described in the 1930s, when in vivo microscopy was used to demonstrate that not all capillaries were perfused during basal conditions and that perfusion of individual capillaries varied over time. These important observations have never been directly confirmed, nor have the hemodynamic causes of the variation been investigated. We used videomicroscopy to record nine consecutive pulmonary capillary perfusion patterns during a 40-min period. Confirming the original work, we found considerable perfusion variation in about one-half of the capillaries. These variations did not correlate with changes in pulmonary arterial pressures or cardiac outputs, suggesting that factors more subtle than large-vessel hemodynamics affected capillary perfusion consistency. In contrast to this variable group, one-half of the capillary segments were consistently perfused during at least eight of the nine observations and were interconnected to form preferential pathways across the alveolar wall.

Animals↗
PubMed1994

Stability of alveolar capillary opening pressures.

Little is known about the stability of the process by which pulmonary capillaries open. To investigate this process, pulmonary capillary perfusion patterns in isolated pump-perfused canine lobes were studied using video microscopy. After pump flow was set to perfuse one-half of the capillaries, the pump was turned off and all of the capillaries emptied. Turning the pump back on reopened the capillaries. The on-off cycle was repeated six times. If the same capillaries were perfused during each observation, it would demonstrate that there were stable and significant differences between individual capillary opening pressures, causing consistent recruitment of those capillaries with the lowest opening pressures. Alternatively, variable perfusion patterns would result if capillary opening pressures changed between observations, if the differences in opening pressures between capillary segments were negligible, or if experimental conditions changed between cycles. The perfusion pattern was more reproducible than expected by chance alone, which indicated the existence of stable differences among alveolar capillary opening pressures.

Animals↗
PubMed1994

[The relationship between pulmonary hemodynamics and chest X-ray findings in patients with sequelae of pulmonary tuberculosis].

For better understanding of pathophysiological aspects of tuberculosis sequelae, we investigated the relationship between pulmonary hemodynamics and chest X-ray findings. One hundred and seven patients with sequelae of pulmonary tuberculosis were examined by the right cardiac catheterization, and pulmonary hemodynamic values were measured and calculated. Chest X-ray findings were defined and classified into the following five items. The items were emphysematous change; fibrosis, bronchiectasis and/or cavity (hereafter abbreviated as "fibrosis"); pulmonary resection and/or atelectasis; pleural thickening; and thoracoplasty. The extent of each finding was defined. We tried to describe chest X-ray findings by applying and categorizing these classifications and the extent to each case. First, we tried to estimate the grade of pulmonary hypertension by categorized X-ray findings. Further, we analyzed what kinds of findings were most influential on the increase of pulmonary artery mean pressure (PPA) and pulmonary arteriolar resistance (PAR). Secondly, we investigated whether PPA, cardiac index (CI) and PAR changed before and after oxygen administration. Thirdly, we analyzed what kind of X-ray findings most affected pulmonary hemodynamics under 100% oxygen administration for 10 minutes. The results were as follows: (1) Out of 107 cases, it was possible to predict PPA by categorized chest X-ray findings in 75 cases by Hayashi's first method of quantification, one of multivariative analyses. "Pleural thickening" was the most influential finding on the increase of PPA. "Fibrosis" was the most influential on the increase of PAR. (2) The values of PPA, CI and PAR decreased more after 100% oxygen administration than under room air breathing. Therefore, PAR was used as the index to estimate pulmonary hemodynamics under the condition of oxygen administration. (3) It was possible to measure PAR under oxygen administration (PARO2) in 72 cases. "Emphysematous change" was the most influential X-ray finding on the increase of PARO2. From these results, it was thought that pulmonary circulatory disorder in patients with tuberculosis sequelae was caused by the combination of various chest X-ray findings with the different extent. It was possible to predict pulmonary hypertension to a certain degree from categorized chest X-ray findings. It was suggested that "emphysematous change" less related to hypoxic pulmonary vasoconstriction than "fibrosis" and "pleural thickening" from the results of comparison among the partial correlation coefficients, which were associated with the increase of PAR under room air breathing and oxygen administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1994

[Relation of pulmonary vascular response to pressure-flow relationship during incremental exercise in patients with chronic obstructive pulmonary disease (COPD)].

Twenty-eight COPD patients underwent right heart catheterization while in clinically stable condition. Pulmonary vascular response to oxygen was evaluated by the percent change in pulmonary arteriolar resistance after 100% oxygen inhalation (% delta PAR), and its relation to the pressure-flow relationship during incremental exercise was assessed. Mean pulmonary arterial pressure (PPA) during exercise was plotted against the cardiac index (C.I.) from rest to maximal exercise in each patient. In most of the patients, the changes in PPA were nearly linear to the C.I. Therefore, a slope could be obtained from the regression equation in each patient. Patients were divided into two groups according to whether their % delta PAR was greater than 20 defined as a responder (RES), or less than five defined as a non-responder (N-RES). Seven out of 28 patients were RES, nine were N-RES, RES showed a higher %FEV1.0 level, C.I. and stroke volume index (S.I.) at maximal exercise, and a lower level of RV/TLC as well as slope. The slope correlated significantly with %DLCO (r = -0.724, p < 0.01), baseline PAR (r = 0.562, p < 0.01) and % delta PAR (r = -0.522, p < 0.01). These results suggest that the diminished pulmonary vascular bed, and the distensibility of pulmonary vessels, appear to contribute to the steepness of the slope and reduced % delta PAR in patients with COPD.

Administration, Inhalation↗
PubMed1993

Direct measurement of pulmonary microvascular distensibility.

Pulmonary vascular distensibility has an important influence on pulmonary hemodynamics. Although many measurements of distensibility have been made on large pulmonary vessels, there is less information on microvascular distensibility. We have measured the distensibility of the smallest (< 70-microns-diam) precapillary arterioles and postcapillary venules. Isolated dog lobes, at 2.5 cmH2O transpulmonary pressure, were perfused at low flows, which caused the arteriovenous pressure gradient to be very small and thereby permitted accurate estimation of microvascular pressure. As microvascular pressure was systematically varied between 0 and 30 mmHg, subpleural microvascular diameters were determined from computer-enhanced images obtained by videomicroscopy. Arteriolar and venular distensibilities were not different from each other. The microvascular pressure-diameter relationship was alinear with distensibility coefficients of 1-3% mmHg-1, values that are of the same order of magnitude as previously measured distensibilities of 100- to 1,000-microns-diam canine pulmonary vessels.

Animals↗
PubMed1993

[A case of pulmonary thromboembolism associated with heparin-induced thrombocytopenia].

A 41-year-old man was admitted to our hospital for dyspnea on exertion and chest oppression. He was diagnosed as having pulmonary thromboembolism by pulmonary perfusion scan and angiography. An anticoagulant (heparin) and fibrinolytic (urokinase) therapy were administered to him as standard therapy. Six days after continuous infusion of heparin, however, he complained of worsening of dyspnea associated with severe hypoxemia and thrombocytopenia. Because heparin-induced thrombocytopenia was suspected, heparin administration was discontinued. Shortly after switching anticoagulant therapy from heparin to warfarin, the patient's symptom improved and his platelet count returned to the pretreatment value. In this case, it was thought that an immune-mediated response contributed to this heparin-induced thrombo-cytopenia. Moreover, we revealed platelet aggregating factor in the patient's plasma. This case illustrates that caution must be taken in the use of heparin for anticoagulant therapy in patients with pulmonary thromboembolism.

Adult↗
PubMed1993

[Pulmonary hemodynamic effects of cold pressor test in patients with chronic lung disease].

Cold Pressor Test (CPT) was applied to patients with chronic lung disease, including primary pulmonary hypertension, and the effects on pulmonary circulation were compared to those on systemic circulation. HR PPA, and TPR showed maximum values at the end of CPT (Time = 0) and recovered to baseline values 5 min after CPT. CO, however, did not change significantly after CPT. PPA and PAR showed maximum values at the end of CPT and then gradually decreased, but still were significantly higher than baseline values at 5 min after CPT. Nifedipine (NFP) reduced the maximum values of both TPR and PAR at the end of CPT. There was significant correlation between PPA change after CPT and baseline PPA value, and NFP decreased the slope of the regression line. These results indicate that cold stimulation induces both systemic and pulmonary vasoconstriction in patients with chronic lung disease, and this pulmonary vasoconstriction was correlated to the baseline pulmonary vascular tone. Moreover, nifedipine may reduce this cold stimulation-induced pulmonary vasoconstriction.

Chronic Disease↗
PubMed1992

Capillary perfusion patterns in single alveolar walls.

We studied capillary perfusion patterns in single alveolar walls through a transparent thoracic window implanted in pentobarbital-anesthetized dogs. The capillaries were maximally opened by brief inflation of a balloon in the left atrium to raise pressure. After the balloon was deflated and pulmonary hemodynamics returned to zone 2 baseline conditions, the capillaries that remained perfused in the observed field were videotaped with the use of in vivo microscopy. The cycle of elevated pressure and baseline observation was repeated three times. Perfusion of different capillaries during each of the observations would imply that the capillaries had characteristics that permitted flow to switch between segments. Perfusion of a specific set of pathways through the network each time would demonstrate that flowing blood sought a unique and repeatable combination of segments, presumably with the least total pathway resistance. We found that the same capillary segments were perfused 79% of the time, a strong indication that a reproducible combination of individual segmental resistances determined the predominant pattern of pulmonary capillary perfusion.

Animals↗
PubMed1992

[Relationship between signal intensity of blood flow in the pulmonary artery obtained by magnetic resonance imaging and results of right cardiac catheterization in patients with pulmonary disease].

Electrocardiogram-gated spin-echo magnetic resonance (MR) images of the chest were obtained in five normal controls and 35 patients with pulmonary disease (11 chronic obstructive pulmonary disease, 6 pulmonary thromboembolism, 5 primary pulmonary hypertension, 4 interstitial pulmonary disease, 4 pulmonary hypertension with disturbance of portal circulation, and 5 other diseases) who underwent right cardiac catheterization. In transverse images at the level of the right main pulmonary artery (rPA) and sagittal images at the level through the midsternal line and the spinal chord, the signal intensity of blood flow in the rPA was quantitatively evaluated, and the correlations with the MR signal intensity of intravascular flow and the parameters of hemodynamics were studied. In diastole MR images of both normal controls and patients mostly showed a significant signal intensity of flowing blood, but in systole some patients demonstrated significant signals and visible flow images. In systolic MR images, the mean values of hemodynamic parameters (mean pulmonary arterial pressure (mPAP), pulmonary arteriolar resistance (PAR), and cardiac index (CI)) were abnormal in patients with significant signal intensity of flow compared with those in patients without sufficient MR signal. The signal intensity was not correlated with mPAP; however, it significantly increased as PAR increased, and it increased as CI decreased both in diastole and in systole. Especially in systole, there was good correlation between the signal intensity in transverse MR images and CI (r = -0.85, P less than 0.01) and between signal intensity in sagittal MR images and PAR (r = 0.90, P less than 0.01). These results suggest that significant flow signal in the rPA in systole has pathophysiological significance, and signal intensity is considered to be significantly affected by changes of PAR and CI. The signal intensity of blood flow in the rPA on MR images can be used as an index of the severity of right heart failure associated with pulmonary disease. MR imaging is a useful modality to evaluate pulmonary circulation disturbance because of its ability to assess blood flow in the pulmonary artery noninvasively without interference from other structures such as bone and normal lung.

Adult↗