Attenuation of hypercapnic carbon dioxide chemosensitivity after postinfarction exercise training: possible contribution to the improvement in exercise hyperventilation

OBJECTIVE

To elucidate the responsible mechanisms of increased slope of minute ventilation relative to carbon dioxide production (VE/VCO(2)) during exercise after acute myocardial infarction without overt signs of heart failure, patients who had an acute myocardial infarction were examined after participating in a three month supervised exercise training programme.

DESIGN

Exercise testing, hypercapnic CO(2) chemosensitivity measurement (rebreathing method), and pulmonary function test were repeated at entry and after three months in 50 acute myocardial infarction patients with neither symptoms nor signs of heart failure who completed the training programme. Ten patients who performed initial inhospital training served as controls.

RESULTS

Age, peak oxygen uptake, left ventricular ejection fraction, CO(2) chemosensitivity, respiratory parameters (percentage of predicted normal vital capacity (%VC), forced expiratory volume in one second, and carbon monoxide transfer factor (%TLCO)) were all significantly correlated with VE/VCO(2) slope. Multivariate regression analysis showed that age (beta = 0.29, p = 0.01), %TLCO (beta = -0.27, p = 0.01), and CO(2) chemosensitivity (beta = 0.49, p < 0.001) were independent determinants of VE/VCO(2) slope. After three months, there was no significant change in these parameters in the control group. Peak oxygen uptake, %TLCO, and %VC and attenuation in CO(2) chemosensitivity increased significantly in the training group. The VE/VCO(2) slope decreased marginally (p = 0.11). The changes in VE/VCO(2) slope were correlated only with those in CO(2) chemosensitivity (r = 0.50, p < 0.001).

CONCLUSION

After acute myocardial infarction, exercise hyperventilation is seen in association with aging, enhanced hypercapnic CO(2) chemosensitivity, and reduced TLCO, even in the absence of overt heart failure. The correlation of VE/VCO(2) attenuation after training with the reduction in CO(2) chemosensitivity suggests that exercise training may reduce increased VE/VCO(2) slope, at least partially by reducing CO(2) chemosensitivity.

Oral beraprost sodium improves exercise capacity and ventilatory efficiency in patients with primary or thromboembolic pulmonary hypertension

OBJECTIVE

To investigate the effect of beraprost sodium, an orally active prostacyclin analogue, on exercise capacity and ventilatory efficiency in patients with primary pulmonary hypertension and chronic thromboembolic pulmonary hypertension.

PATIENTS AND DESIGN

Symptom limited cardiopulmonary exercise testing was performed before and 3 (1) months (mean (SEM)) after beraprost treatment in 30 patients with precapillary pulmonary hypertension (14 with primary pulmonary hypertension and 16 with chronic thromboembolic pulmonary hypertension).

RESULTS

Long term treatment with beraprost resulted in significant increases (mean (SEM)) in peak workload (87 (4) W to 97 (5) W, p < 0.001) and peak oxygen consumption (peak VO2, 14.9 (0.7) ml/kg/min to 16.8 (0.7) ml/kg/min, p < 0.001). Beraprost decreased the ventilatory response to carbon dioxide production during exercise (VE-VCO2 slope, 42 (2) to 37 (1), p < 0.001). No significant difference in the responses of these variables to beraprost treatment was observed between patients with primary pulmonary hypertension and chronic thromboembolic pulmonary hypertension.

CONCLUSIONS

Oral administration of beraprost sodium may improve exercise capacity and ventilatory efficiency in patients with both primary and chronic thromboembolic pulmonary hypertension.

Acute and chronic effects of surgical thromboendarterectomy on exercise capacity and ventilatory efficiency in patients with chronic thromboembolic pulmonary hypertension

OBJECTIVE

To assess acute and chronic effects of surgical thromboendarterectomy on exercise capacity and ventilatory efficiency in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

DESIGN

Cardiopulmonary exercise testing was performed in 20 patients with CTEPH before thromboendarterectomy (baseline), one month after (early phase), and four months after (late phase). Peak oxygen uptake (peak VO(2)) and the ventilatory response to carbon dioxide production (VE-VCO(2) slope) were measured for assessment of exercise capacity and ventilatory efficiency. Right heart catheterisation was performed in all patients before and one month after surgery.

RESULTS

Baseline peak VO(2) decreased and VE-VCO(2) slope increased along with the increase in pulmonary vascular resistance in patients with CTEPH. After thromboendarterectomy, the VE-VCO(2) slope decreased greatly from baseline to the early phase (mean (SD), 50 (9) to 37 (7), p < 0.05) and reached a steady level thereafter. In contrast, a continued increase in peak VO(2) was noted from the early to the late phase (16.9 (4.1) to 21.1 (5.0) ml/kg/min, p < 0.05). The decrease in the VE-VCO(2) slope from baseline to the early phase, but not the increase in peak VO(2), correlated strongly with the decrease in pulmonary vascular resistance after surgery (r = 0.75, p < 0.01).

CONCLUSIONS

Thromboendarterectomy may cause an immediate improvement in ventilatory efficiency, possibly through its beneficial haemodynamic effects. In contrast, exercise capacity may continue to improve towards the late phase, reflecting peripheral adaptation to exercise.

Acute and chronic effects of surgical thromboendarterectomy on exercise capacity and ventilatory efficiency in patients with chronic thromboembolic pulmonary hypertension

OBJECTIVE

To assess acute and chronic effects of surgical thromboendarterectomy on exercise capacity and ventilatory efficiency in patients with chronic thromboembolic pulmonary hypertension (CTEPH).

DESIGN

Cardiopulmonary exercise testing was performed in 20 patients with CTEPH before thromboendarterectomy (baseline), one month after (early phase), and four months after (late phase). Peak oxygen uptake (peakV˙o2) and the ventilatory response to carbon dioxide production (V˙e-V˙co2 slope) were measured for assessment of exercise capacity and ventilatory efficiency. Right heart catheterisation was performed in all patients before and one month after surgery.

RESULTS

Baseline peakV˙o2 decreased andV˙e-V˙co2 slope increased along with the increase in pulmonary vascular resistance in patients with CTEPH. After thromboendarterectomy, theV˙e-V˙co2 slope decreased greatly from baseline to the early phase (mean (SD), 50 (9) to 37 (7), p < 0.05) and reached a steady level thereafter. In contrast, a continued increase in peak V˙o2 was noted from the early to the late phase (16.9 (4.1) to 21.1 (5.0) ml/kg/min, p < 0.05). The decrease in theV˙e-V˙co2 slope from baseline to the early phase, but not the increase in peakV˙o2, correlated strongly with the decrease in pulmonary vascular resistance after surgery (r = 0.75, p < 0.01).

CONCLUSIONS

Thromboendarterectomy may cause an immediate improvement in ventilatory efficiency, possibly through its beneficial haemodynamic effects. In contrast, exercise capacity may continue to improve towards the late phase, reflecting peripheral adaptation to exercise.

Pulmonary artery reflection for differentially diagnosing primary pulmonary hypertension and chronic pulmonary thromboembolism

OBJECTIVES

The purpose of this investigation was to differentiate chronic pulmonary thromboembolism (CPTE) from primary pulmonary hypertension (PPH) by means of the indexes of pulmonary arterial reflection.

BACKGROUND

These differences in the primary lesions would make pulmonary artery reflection occur earlier in CPTE than in PPH. Although the analysis of pulsatility of pulmonary arterial pressure is useful in the differential diagnosis of PPH and CPTE, it is not known whether the analysis of pulmonary artery reflection can differentiate CPTE from PPH.

METHODS

Since CPTE predominantly involves the proximal arteries, whereas PPH involve the peripheral arteries, we hypothesized that patients with CPTE have a large augmentation index and a short inflection time. For this study, we enrolled 62 patients who had CPTE (31 patients) and PPH (31 patients). We measured pulmonary arterial pressure using a fluid filled system that included a balloon-tipped flow directed catheter. To quantify the pulmonary artery reflection, we used the augmentation index and inflection time.

RESULTS

The augmentation index was markedly higher in CPTE than it was in PPH (27.4% +/- 15.2% [SD] and -25.1% +/- 26.9%, respectively, p < 0.001) and was diagnostic in separating the two groups. Inflection time separated the two groups reasonably well (97 +/- 20 ms and 210 +/- 49 ms, respectively, p < 0.001).

CONCLUSIONS

The analysis of pulmonary arterial reflection is useful in the differential diagnosis of CPTE and PPH.

[Coagulation and fibrinolytic abnormality related to endothelial injury in pulmonary arterial hypertension]

It remains unclear whether a coagulation abnormality plays an important role in the clinical course in pulmonary arterial hypertension as well as vasoconstriction and vascular-wall remodeling, although several studies of pathological specimens and clinical studies demonstrating that anticoagulation prolongs life have suggested the importance of thrombosis. Several parameters for hemostasis related to endothelial injury are expected to reflect abnormal coagulation and fibrinolytic systems in pulmonary hypertension. Recently, we demonstrated that plasma level of soluble P-selectin was increased and that of thrombomodulin (TM) was decreased in patients with pulmonary arterial hypertension. The abnormal values of P-selectin and TM were improved by continuous prostacyclin infusion. Altered hemostasis may be important as a pathogenesis in pulmonary hypertension and adequate anti-coagulant therapy is expected.

Short-term oral administration of L-arginine improves hemodynamics and exercise capacity in patients with precapillary pulmonary hypertension

We sought to assess the effects of oral supplementation of L-arginine, the precursor of nitric oxide (NO), on hemodynamics and exercise capacity in patients with pulmonary hypertension. Acute hemodynamic responses to oral L-arginine (0.5 g/10 kg body weight) or placebo were examined in 19 patients with primary or precapillary secondary pulmonary hypertension. Cardiopulmonary exercise tests were performed to measure peak oxygen consumption (peak V O(2)) and the ventilatory response to carbon dioxide production (V E-V CO(2) slope) before and 1 wk after treatment with L-arginine (1.5 g/10 kg body weight/d) or placebo. Oral supplementation of L-arginine significantly increased plasma L-citrulline, which indicated enhancement of NO production. Supplemental L-arginine produced a 9% decrease in mean pulmonary arterial pressure (53 +/- 4 to 48 +/- 4 mm Hg, p < 0.05) and a 16% decrease in pulmonary vascular resistance (14.8 +/- 1.5 to 12.4 +/- 1.4 Wood units, p < 0.05). L-arginine modestly decreased mean systemic arterial pressure (92 +/- 4 to 87 +/- 3 mm Hg, p < 0.05). A 1-wk supplementation of L-arginine resulted in a slight increase in peak V O(2) (831 +/- 88 to 896 +/- 92 ml/min, p < 0.05) and a significant decrease in the V E- V CO(2) slope (43 +/- 4 to 37 +/- 3, p < 0.05) without significant systemic hypotension. Hemodynamics and exercise capacity remained unchanged during placebo administration. These results suggest that oral supplementation of L-arginine may have beneficial effects on hemodynamics and exercise capacity in patients with precapillary pulmonary hypertension.

[Plasma brain natriuretic peptide as a prognostic indicator in patients with primary pulmonary hypertension]

BACKGROUND

Plasma brain natriuretic peptide (BNP) level increases in proportion to the degree of right ventricular dysfunction in pulmonary hypertension. We sought to assess the prognostic significance of plasma BNP in patients with primary pulmonary hypertension.

METHODS AND RESULTS

Plasma BNP was measured in 60 patients with primary pulmonary hypertension at diagnostic catheterization, together with atrial natriuretic peptide, norepinephrine, and epinephrine. Measurements were repeated in 53 patients after a mean follow-up period of 3 months. Forty-nine of the patients received intravenous or oral prostacyclin. During a mean follow-up period of 24 months, 18 patients died of cardiopulmonary causes. According to multivariate analysis, baseline plasma BNP was an independent predictor of mortality. Patients with a supramedian level of baseline BNP (> or = 150 pg/ml) had a significantly lower survival rate than those with an inframedian level, according to Kaplan-Meier survival curves (p < 0.05). Plasma BNP in survivors decreased significantly during the follow-up (217 +/- 38 to 149 +/- 30 pg/ml, p < 0.05), whereas that in nonsurvivors increased (365 +/- 77 to 544 +/- 68 pg/ml, p < 0.05). Thus, survival was strikingly worse for patients with a supramedian value of follow-up BNP (> or = 180 pg/ml) than for those with an inframedian value (p < 0.0001).

CONCLUSIONS

A high level of plasma BNP, and in particular, a further increase in plasma BNP during follow-up, may have a strong, independent association with increased mortality in patients with primary pulmonary hypertension.

[Pulmonary thromboendarterectomy for chronic pulmonary thromboembolism in three patients with systemic lupus erythematosus and antiphospholipid syndrome]

Pulmonary hypertension (PH) is a serious and often fatal complication of systemic lupus erythematosus (SLE). Several potential mechanisms have been postulated for narrowing of vessels as a result of pulmonary vasculitis and pulmonary thromboembolism caused by antiphospholipid antibodies. Pulmonary thromboendarterectomy for chronic pulmonary thromboembolism is performed to alleviate pulmonary hypertension. We report three rare cases of SLE with antiphospholipid syndrome in patients who presented with PH secondary to chronic pulmonary thromboembolism. Pulmonary thromboendarterectomy was performed, and all patients remained well without deterioration of PH after surgery. Pulmonary thromboendarterectomy should be considered as an effective method of treatment for this disease.

Haemodynamic and hormonal effects of adrenomedullin in patients with pulmonary hypertension

OBJECTIVE

To investigate whether infusion of adrenomedullin, a potent vasorelaxant peptide, has beneficial haemodynamic and hormonal effects in patients with pulmonary hypertension.

PATIENTS AND DESIGN

The haemodynamic and hormonal responses to intravenous infusion of adrenomedullin (0.05 microgram/kg/min) or placebo were examined in 13 patients with precapillary pulmonary hypertension.

RESULTS

Infusion of adrenomedullin produced a 44% increase in cardiac index (mean (SD) 1.8 (0.2) to 2.6 (0.3) l/min/m(2), p < 0. 05) and a 32% decrease in pulmonary vascular resistance (19.7 (1.4) to 13.4 (1.3) units, p < 0.05), with a 4% reduction in mean pulmonary arterial pressure (62 (4) to 59 (4) mm Hg, NS). Adrenomedullin also decreased mean systemic arterial pressure (81 (3) to 72 (4) mm Hg, p < 0.05) and increased heart rate (73 (4) to 79 (4) beats/min, p < 0.05). Adrenomedullin decreased plasma aldosterone (9.8 (2.5) to 7.1 (1.5) ng/dl, p < 0.05) without significant changes in plasma renin activity. Plasma atrial and brain natriuretic peptides tended to decrease with adrenomedullin, although these changes did not reach significance. The haemodynamic and hormonal variables remained unchanged during placebo infusion.

CONCLUSIONS

Intravenous adrenomedullin has beneficial haemodynamic and hormonal effects in patients with precapillary pulmonary hypertension.

Increased plasma P-selectin and decreased thrombomodulin in pulmonary arterial hypertension were improved by continuous prostacyclin therapy

BACKGROUND

Thrombosis in situ related to endothelial cell injury may contribute to the development of pulmonary hypertension (PH). P-selectin, a leukocyte adhesion receptor present in endothelial cells and platelets, reflects endothelial injury and platelet activation, and thrombomodulin (TM), a receptor for thrombin and a major anticoagulant proteoglycan on the endothelial membrane, reflects the anticoagulant activity of the endothelium.

METHODS AND RESULTS

To assess abnormal coagulation due to endothelial injury in patients with PH, plasma levels of soluble P-selectin and TM were measured in 32 patients with primary PH (PPH), 25 with secondary pulmonary arterial hypertension (sPAH), 31 with pulmonary venous hypertension (PVH), and 17 healthy subjects (Control). These measurements were repeated after continuous infusion of prostacyclin in 15 patients with PPH and 3 with sPAH. P-selectin levels in both the sPAH and PPH groups were significantly higher than those in the Control and PVH groups (P<0.05). Plasma TM level in the PPH group was significantly lower than those in the other groups (P<0.01). After prostacyclin therapy, the lower TM level was increased and the higher P-selectin level was decreased (P<0.05).

CONCLUSIONS

Decreased TM and increased P-selectin in PPH and sPAH may reflect in situ thrombosis due to endothelial injury. Prostacyclin may act not only as a vasodilator but also as an agent that improves endothelial injury and altered hemostasis in pulmonary arterial injury.

Plasma brain natriuretic peptide as a prognostic indicator in patients with primary pulmonary hypertension

BACKGROUND

Plasma brain natriuretic peptide (BNP) level increases in proportion to the degree of right ventricular dysfunction in pulmonary hypertension. We sought to assess the prognostic significance of plasma BNP in patients with primary pulmonary hypertension (PPH).

METHODS AND RESULTS

Plasma BNP was measured in 60 patients with PPH at diagnostic catheterization, together with atrial natriuretic peptide, norepinephrine, and epinephrine. Measurements were repeated in 53 patients after a mean follow-up period of 3 months. Forty-nine of the patients received intravenous or oral prostacyclin. During a mean follow-up period of 24 months, 18 patients died of cardiopulmonary causes. According to multivariate analysis, baseline plasma BNP was an independent predictor of mortality. Patients with a supramedian level of baseline BNP (>/=150 pg/mL) had a significantly lower survival rate than those with an inframedian level, according to Kaplan-Meier survival curves (P<0.05). Plasma BNP in survivors decreased significantly during the follow-up (217+/-38 to 149+/-30 pg/mL, P<0. 05), whereas that in nonsurvivors increased (365+/-77 to 544+/-68 pg/mL, P<0.05). Thus, survival was strikingly worse for patients with a supramedian value of follow-up BNP (>/=180 pg/mL) than for those with an inframedian value (P<0.0001).

CONCLUSIONS

A high level of plasma BNP, and in particular, a further increase in plasma BNP during follow-up, may have a strong, independent association with increased mortality rates in patients with PPH.

A case of constrictive pericarditis with local thickening of the pericardium without manifest ventricular interdependence

This is the first case report of postsurgical constrictive pericarditis confined to the left ventricle in which the majority of diagnosis tests were not indicative of the disease. A 50-year-old woman with a past history of mitral valve replacement was admitted for right heart failure. Cardiac catheterization showed impaired diastolic filling but lacked the characteristic ventricular interdependence recently reported to be specific for the disease, without manifest radiological appearance of pericardial thickening. However, a new technique using magnetic resonance tagging cine revealed pericardial adhesion, limited to the left ventricle, which was confirmed during pericardiectomy. After the surgery, right heart failure and diastolic filling abnormality disappeared with restoration of normal heart pressures.

Correlation between severity of pulmonary arterial hypertension and 123I-metaiodobenzylguanidine left ventricular imaging

It remains unclear whether cardiac sympathetic nervous function is disturbed in patients with pulmonary arterial hypertension (PH) and how sympathetic dysfunction is related to PH.

METHODS

In this study, (123)I-metaiodobenzylguanidine (MIBG) imaging of the heart, which reveals the sympathetic innervation of the left ventricle, was performed in 7 healthy volunteers without cardiopulmonary disease (control subjects); 55 patients with PH, including 27 with chronic thromboembolic pulmonary hypertension (CTEPH) of major vessels; and 28 patients with primary pulmonary hypertension (PPH).

RESULTS

Cardiac (123)I-MIBG uptake, assessed as the heart-to-mediastinum activity ratio (H/M), was significantly lower in the CTEPH and PPH groups compared with that in the control group (P < 0.01). Myocardial MIBG turnover, expressed as the washout rate (WR [%]) from 15 to 240 min, was significantly higher in the CTEPH and PPH groups than that in the control group (P < 0.01). In the PPH group, H/M and WR values of MIBG correlated with the severity of pulmonary hypertension (represented by total pulmonary vascular resistance determined by right heart catheterization), the right ventricular ejection fraction determined by electron beam CT, and other variables but did not correlate well in the CTEPH group. In both groups, patients with H/M > or = 2.0 showed better cumulative survival than did those with H/M < 2.0 (P < 0.05).

CONCLUSION

Patients with PH have significant left ventricular myocardial sympathetic nervous alteration. (123)I-MIBG imaging of the heart is useful for assessing the severity of pulmonary hypertension caused by PPH or CTEPH.

Haemodynamic correlates and prognostic significance of serum uric acid in adult patients with Eisenmenger syndrome

OBJECTIVE

To assess haemodynamic correlates and prognostic significance of serum uric acid in adult patients with Eisenmenger syndrome.

DESIGN

Retrospective observational study.

SETTING

Tertiary referral centre.

PATIENTS

94 adult patients with Eisenmenger syndrome who were diagnosed between September 1982 and July 1998.

MAIN OUTCOME MEASURES

Serum uric acid was measured in all patients, together with clinical and haemodynamic variables related to mortality.

RESULTS

Serum uric acid was raised in patients with Eisenmenger syndrome compared with age and sex matched control subjects (7.0 v 4.7 mg/dl, p < 0.0001) and increased in proportion to the severity of New York Heart Association functional class. Serum uric acid was positively correlated with mean pulmonary arterial pressure (r = 0.30, p = 0.0052) and total pulmonary resistance index (r = 0.55, p < 0.0001), and negatively correlated with cardiac index (r = -0.50, p < 0.0001). During a mean follow up period of 97 months, 38 patients died of cardiopulmonary causes. Among various clinical, echocardiographic, and laboratory variables, serum uric acid remained predictive in multivariate analysis. Kaplan-Meier survival curves based on median serum uric acid showed that patients with high values had a significantly worse survival rate than those with low values (log-lank test: p = 0.0014 in male patients, p = 0.0034 in female patients).

CONCLUSIONS

Serum uric acid increases in proportion to haemodynamic severity in adult patients with Eisenmenger syndrome and is independently associated with long term mortality.

Improvement in exercise capacity with nitric oxide inhalation in patients with precapillary pulmonary hypertension

BACKGROUND

Patients with precapillary pulmonary hypertension (PH) exhibit a poor exercise capacity due to an impaired vasodilatory response of their pulmonary arteries. By causing the pulmonary artery to dilate, inhaled nitric oxide (NO) may allow an increase in exercise capacity in patients with PH.

METHODS AND RESULTS

On 2 separate days, 3 days apart, 14 patients with precapillary PH (10 primary PH, 4 residual PH after correction of an intracardiac shunt; age, 40+/-12 years; mean pulmonary artery pressure, 60+/-23 mm Hg) performed exercise, with and without inhalation of 20 ppm NO, on a cycle ergometer. The work rate was increased 15 W/min until their symptom-limited maximum, with breath-by-breath gas analysis. Patients were randomly and blindly selected to inhale NO on either their first or second test. Peak exercise load and anaerobic threshold tended to increase, but not significantly. Peak oxygen consumption (f1.gif" BORDER="0">O(2)) and Deltaf1.gif" BORDER="0">O(2)/DeltaW ratio increased significantly, by 18% and 22%, respectively (peak f1.gif" BORDER="0">O(2), 13.6+/-3.6 to 16.0+/-4. 1 mL. kg(-1). min(-1); Deltaf1.gif" BORDER="0">O(2)/DeltaW ratio, 5. 8+/-2.4 to 7.1+/-2.3 mL. kg(-1). min(-1). W(-1); both P<0.01). Peak f1.gif" BORDER="0">O(2) increased >10% in 12 of the 14 patients. However, respiratory quotient at peak exercise decreased from 1. 22+/-0.15 to 1.09+/-0.15 (P<0.01).

CONCLUSIONS

Inhaled NO substantially increases oxygen consumption at the same workload during exercise. This finding supports the possibility of ambulatory NO inhalation therapy in patients with precapillary PH.

Hemodynamic, renal, and hormonal effects of adrenomedullin infusion in patients with congestive heart failure

BACKGROUND

Experimental studies have shown that adrenomedullin (AM) causes vasodilatation, diuresis, and a positive inotropic effect. In humans, however, whether infusion of AM has beneficial effects in congestive heart failure (CHF) remains unknown.

METHODS AND RESULTS

Hemodynamic, renal, and hormonal responses to intravenous infusion of human AM (0.05 microg. kg(-1). min(-1)) were examined in 7 patients with CHF and 7 normal healthy subjects (NL). In NL group, AM significantly decreased mean arterial pressure (-16 mm Hg, P<0. 05) and increased heart rate (+12 bpm, P<0.05). In CHF group, AM also decreased mean arterial pressure (-8 mm Hg, P<0.05) and increased heart rate (+5 bpm, P<0.05), but to a much lesser degree (P<0.05 versus NL). AM markedly increased cardiac index (CHF, +49%; NL, +39%, P<0.05) while decreasing pulmonary capillary wedge pressure (CHF, -4 mm Hg; NL, -2 mm Hg, P<0.05). AM significantly decreased mean pulmonary arterial pressure only in CHF (-4 mm Hg, P<0.05). AM increased urine volume (CHF, +48%; NL, +62%, P<0.05) and urinary sodium excretion (CHF, +42%; NL, +75%, P<0.05). Only in CHF, plasma aldosterone significantly decreased during (-28%, P<0.05) and after (-36%, P<0.05) AM infusion. These parameters remained unchanged in 7 patients with CHF and 6 healthy subjects who received placebo.

CONCLUSIONS

Intravenous infusion of AM has beneficial hemodynamic and renal effects in patients with CHF.

Clinical correlates and prognostic significance of six-minute walk test in patients with primary pulmonary hypertension. Comparison with cardiopulmonary exercise testing

The six-minute walk test is a submaximal exercise test that can be performed even by a patient with heart failure not tolerating maximal exercise testing. To elucidate the clinical significance and prognostic value of the six-minute walk test in patients with primary pulmonary hypertension (PPH), we sought (1) to assess the relation between distance walked during the six-minute walk test and exercise capacity determined by maximal cardiopulmonary exercise testing, and (2) to investigate the prognostic value of the six-minute walk test in comparison with other noninvasive parameters. The six-minute walk test was performed in 43 patients with PPH, together with echocardiography, right heart catheterization, and measurement of plasma epinephrine and norepinephrine. Symptom-limited cardiopulmonary exercise testing was performed in a subsample of patients (n = 27). Distance walked in 6 min was significantly shorter in patients with PPH than in age- and sex-matched healthy subjects (297 +/- 188 versus 655 +/- 91 m, p < 0. 001). The distance significantly decreased in proportion to the severity of New York Heart Association functional class. The distance walked correlated modestly with baseline cardiac output (r = 0.48, p < 0.05) and total pulmonary resistance (r = -0.49, p < 0. 05), but not significantly with mean pulmonary arterial pressure. In contrast, the distance walked correlated strongly with peak V O(2) (r = 0.70, p < 0.001), oxygen pulse (r = 0.57, p < 0.01), and V E-VCO(2) slope (r = -0.66, p < 0.001) determined by cardiopulmonary exercise testing. During a mean follow-up period of 21 +/- 16 mo, 12 patients died of cardiopulmonary causes. Among noninvasive parameters including clinical, echocardiographic, and neurohumoral parameters, only the distance walked in 6 min was independently related to mortality in PPH by multivariate analysis. Patients walking < 332 m had a significantly lower survival rate than those walking farther, assessed by Kaplan-Meier survival curves (log-rank test, p < 0.01). These results suggest that the six-minute walk test, a submaximal exercise test, reflects exercise capacity determined by maximal cardiopulmonary exercise testing in patients with PPH, and it is the distance walked in 6 min that has a strong, independent association with mortality.

Abnormality of left ventricular sympathetic nervous function assessed by (123)I-metaiodobenzylguanidine imaging in patients with COPD

BACKGROUND

Cardiac and systemic autonomic nervous function may be impaired in patients with COPD. Few reports, however, have described sympathetic nervous function of the left ventricle (LV) in COPD patients.

STUDY OBJECTIVE

To assess the LV sympathetic nervous function in patients with COPD using (123)I-metaiodobenzylguanidine (MIBG) imaging of the heart.

DESIGN

Prospective comparison of (123)I-MIBG imaging results in COPD patients and normal subjects.

PARTICIPANTS

Twenty-eight patients with COPD without manifest right ventricular overload and 7 volunteers without cardiopulmonary disease (control subjects).

MEASUREMENTS

(123)I-MIBG imaging results and plasma norepinephrine concentration were compared between the COPD and control groups. In the COPD group, pulmonary function tests were performed and all subjects were interviewed about their symptoms.

RESULTS

(123)I-MIBG uptake, assessed as the cardiac to mediastinal activity ratio in the delayed image, was significantly lower in the COPD group than in the control group (p < 0.05). (123)I-MIBG turnover, expressed as the washout rate (WR) of (123)I-MIBG from 15 to 240 min, was significantly higher in the COPD group than in the control group (p < 0.01). In the COPD group, patients with dyspnea showed lower cardiac to mediastinal activity ratios and higher WRs compared with patients who had mild dyspnea. The WR correlated negatively with the vital capacity/predicted value ratio, correlated negatively with the maximal voluntary ventilation volume/predicted value ratio, and correlated positively with the residual volume/total lung capacity ratio in the COPD group. The plasma norepinephrine concentration in COPD patients was higher than that in the control subjects.

CONCLUSION

Patients with COPD have significant sympathetic nervous impairment of the LV myocardium as a result of generalized sympathetic overactivity.

Effect of orally active prostacyclin analogue on survival of outpatients with primary pulmonary hypertension

OBJECTIVES

This study sought to investigate the effect of beraprost sodium (BPS), an orally active prostacyclin analogue, on the survival of outpatients with primary pulmonary hypertension (PPH).

BACKGROUND

Continuous intravenous administration of epoprostenol (prostacyclin) has been shown to improve survival in PPH. However, the effect of oral BPS on survival in PPH remains unknown.

METHODS

Fifty-eight consecutive patients with PPH who could be discharged after the first diagnostic catheterization for PPH were retrospectively divided into two groups: patients treated with BPS (BPS group, n = 24) and those without BPS (conventional group, n = 34). The baseline demographic and hemodynamic data did not significantly differ between the two.

RESULTS

Twenty-seven patients died of cardiopulmonary causes in the conventional group during a mean follow-up period of 44 +/- 45 months. In contrast, only 4 patients died of cardiopulmonary causes in the BPS group during a mean follow-up period of 30 +/- 20 months. In a subsample (n = 15) of patients in the BPS group, mean pulmonary arterial pressure and total pulmonary resistance significantly decreased, respectively, by 13% and 25% during a mean follow-up period of 53 days. Among the variables previously known to be associated with the mortality in PPH, the absence of BPS therapy and the reduced cardiac output were independently related to the mortality by a multivariate Cox proportional hazards regression analysis (both p < 0.05). The Kaplan-Meier survival curves demonstrated that the one-, two- and three-year survival rates for the BPS group were 96%, 86% and 76%, respectively, as compared with 77%, 47% and 44%, respectively, in the conventional group (log-rank test, p < 0.05).

CONCLUSIONS

The oral administration of BPS may have beneficial effects on the survival of outpatients with PPH as compared with conventional therapy alone.

Serum uric acid levels correlate with the severity and the mortality of primary pulmonary hypertension

Serum uric acid (UA), the final product of purine degradation, has been proposed to be a marker for impaired oxidative metabolism and a possible predictor of mortality in patients with chronic heart failure. To elucidate whether serum UA correlates with the severity and the mortality of primary pulmonary hypertension (PPH), serum UA was assessed in 90 patients with PPH together with other clinical variables. Right heart catheterization was performed in all patients. Serum UA was significantly elevated in patients with PPH compared with age-matched control subjects (7.5 +/- 2.5 versus 4.9 +/- 1.2 mg/ml, p < 0.001). Serum UA negatively correlated with cardiac output (r = -0.52, p < 0.001) and positively correlated with total pulmonary resistance (r = 0.57, p < 0.001). Serum UA significantly decreased from 7.1 +/- 1.9 to 5.9 +/- 1.6 mg/dl with vasodilator therapy, associated with a reduction in total pulmonary resistance from 22 +/- 6 to 17 +/- 7 Wood units. During a mean follow-up period of 31 mo, 53 patients died of cardiopulmonary causes. Among noninvasive variables, serum UA was independently related to mortality by a multivariate Cox proportional-hazards analysis. The Kaplan-Meier survival curves according to the median value of serum UA demonstrated that patients with high serum UA had a significantly higher mortality rate than did those with low serum UA (log-rank test, p < 0.01). These results suggest that serum UA increases in proportion to the clinical severity of PPH and has independent association with long-term mortality of patients with PPH.

Effects of lung preservation solutions on PMN activation in vitro

Polymorphonuclear leukocyte (PMN) activation and PMN-endothelial cell interactions may cause graft failure due to ischemia-reperfusion injury after lung transplantation. We investigated the effects of Euro-Collins solution (EC), low-potassium dextran solution (LPD), and EC plus pentoxifylline (EC-PTXF) on adhesion molecule (CD11b/CD18 and L-selectin) expression, chemotaxis, and oxidative burst of PMN. PMN from healthy human volunteers were incubated with EC, LPD, and EC-PTXF, and, in controls, without preservation solution. LPD exerted a suppressive effect on PMN chemotaxis as compared to EC (P < 0.05), but had no attenuating effect on the increase of CD11b/CD18, the shedding of L-selectin, and intracellular oxidant generation. EC-PTXF attenuated the expression of CD11b/CD18 and the oxidative burst as compared to EC alone (P < 0.05). These effects of LPD and PTXF on PMN function may contribute to successful organ preservation in transplantation.

Clinical and immunoregulatory effects of roxithromycin therapy for chronic respiratory tract infection

The clinical and immunoregulatory effects of long-term macrolide antibiotic therapy for patients with chronic lower respiratory tract infections (CLRTI) were investigated. Clinical parameters and neutrophil chemotactic mediators in the epithelial lining fluid (ELF) of CLRTI patients (n = 10) were examined before and after 3 months oral administration of roxithromycin (RXM). The in vitro effects of RXM were also examined on the release of these mediators from alveolar macrophages (AM) and neutrophils. Arterial oxygen tension (p<0.05), vital capacity (VC) (p<0.001), %VC (p<0.05) and forced expiratory volume in one second (p<0.01) were improved after RXM treatment, but airway bacteria were not eradicated. Among the mediators, the levels of interleukin (IL)-8, neutrophil elastase (NE) and leukotriene B4 (LTB4) were higher in ELF than in plasma of CLRTI patients and they decreased after RXM treatment (n = 7, p<0.05 for each). RXM concentrations were significantly increased in the bronchoalveolar lavage cells of the treated patients. In in vitro experiments, RXM showed inhibitory effects on IL-8 release from AM and neutrophils. In conclusion, interleukin-8, neutrophil elastase and leukotriene B4 contribute to the neutrophilic inflammation in the airways of chronic lower respiratory tract infection patients and the clinical effects of roxithromycin may, in part, be attributable to the suppression of excess release of the chemotactic mediators from inflammatory cells.

Clinical and immunoregulatory effects of roxithromycin therapy for chronic respiratory tract infection

The clinical and immunoregulatory effects of long-term macrolide antibiotic therapy for patients with chronic lower respiratory tract infections (CLRTI) were investigated. Clinical parameters and neutrophil chemotactic mediators in the epithelial lining fluid (ELF) of CLRTI patients (n = 10) were examined before and after 3 months oral administration of roxithromycin (RXM). The in vitro effects of RXM were also examined on the release of these mediators from alveolar macrophages (AM) and neutrophils. Arterial oxygen tension (p<0.05), vital capacity (VC) (p<0.001), %VC (p<0.05) and forced expiratory volume in one second (p<0.01) were improved after RXM treatment, but airway bacteria were not eradicated. Among the mediators, the levels of interleukin (IL)-8, neutrophil elastase (NE) and leukotriene B4 (LTB4) were higher in ELF than in plasma of CLRTI patients and they decreased after RXM treatment (n = 7, p<0.05 for each). RXM concentrations were significantly increased in the bronchoalveolar lavage cells of the treated patients. In in vitro experiments, RXM showed inhibitory effects on IL-8 release from AM and neutrophils. In conclusion, interleukin-8, neutrophil elastase and leukotriene B4 contribute to the neutrophilic inflammation in the airways of chronic lower respiratory tract infection patients and the clinical effects of roxithromycin may, in part, be attributable to the suppression of excess release of the chemotactic mediators from inflammatory cells.

Reduced lipid peroxidation and ischemia-reperfusion injury after lung transplantation using low-potassium dextran solution for lung preservation

Ischemia-reperfusion injury is one of the significant problems in clinical lung transplantation. We investigated the effect of lung preservation with Euro-Collins solution (EC group) or low-potassium dextran solution (LPD group) on lipid peroxidation and ischemia-reperfusion injury in a pig model of lung allotransplantation. The donor lungs were preserved at 4 degrees C for 18 h. Left-sided single lung transplantation was performed, followed by 6 h of reperfusion. Lipid peroxidation was measured as thiobarbituric acid-reactive materials (TBARM) in bronchoalveolar lavage (BAL) fluid and effluent solutions from pulmonary artery (Effluent). After 18 h of ischemia, the LPD group showed lower TBARM in BAL and Effluent than the EC group (p < 0.05). After ischemia plus reperfusion, lung wetto-dry weight ratios and TBARM levels in BAL in the LPD group were lower than those of the EC group (p < 0.05). Lung wet-to-dry weight ratios correlated with TBARM levels in BAL (p < 0.05, r = 0.50). We conclude lipid peroxidation in BAL and Effluent may reflect the degree of ischemia-reperfusion injury, and lung preservation with LPD can reduce lipid peroxidation and lung injury as compared with EC.

A derivative of cationic antimicrobial protein attenuates lung injury by suppressing cell adhesion

Cationic antimicrobial protein of 18 kD (CAP18) was identified and purified from rabbit granulocytes and shown to inhibit various activities of lipopolysaccharide (LPS). We investigated the effect of a 32-amino-acid C-terminal fragment of CAP18 (CAP18-derived peptide, CDP) on the pathogenesis of acute lung injury caused by intravenous endotoxin. Guinea pigs were divided into six groups: (I) saline control (n = 8), (2) CDP-alone (n = 8), (3) LPS-alone (n = 8), (4) LPS+CDP0m (n = 8), (5) LPS+CDP10m (n = 8), and (6) LPS+CDP60m (n = 8). A CDP dose of 0.2 mg/kg was injected at various time points after LPS injection. Lung wet-to-dry weight ratio, [125I]albumin leakage in lung tissue and bronchoalveolar lavage (BAL) fluid, differential cell count in BAL fluid, and histopathologic features were examined 4 h after intravenous administration of 0.02 mg/kg of LPS. The LPS+CDP0m and the LPS+CDP10m groups showed significantly attenuated lung injury compared to that seen in the LPS-alone group, however the LPS+CDP60m group revealed no attenuation of lung injury. The accumulation of peripheral white blood cells into pulmonary vasculature was attenuated only in the LPS+CDP0m but not in the LPS+CDP10m groups. We examined the effect of CDP on the expression of adhesion molecules using human umbilical vein endothelial cells, the result of which showed that CDP suppressed the LPS-induced expression of adhesion molecules in a dose-dependent manner. We conclude that CDP attenuates inflammatory cell migration into alveoli resulting in the attenuation of lung injury.

Protective effect of B464, a lipid A analog, on endotoxin-induced cellular responses and acute lung injury

B464 is a novel synthetic analog of lipid A, a toxic component of endotoxin (LPS; lipopolysaccharide). We investigated the effects of B464 on both LPS-induced cellular responses in vitro and acute lung injury in vivo. In the in vitro study, B464 inhibited tumor necrosis factor-alpha (TNF-alpha) production from human monocytes, priming and stiffening of neutrophils, and expression of adhesion molecules on endothelial cells induced by LPS. We then studied the effects of B464 pretreatment on acute lung injury elicited by intravenous LPS administration in vivo. Guinea pigs were divided into saline control, B464 alone, LPS alone, and LPS + B464 groups. Animals were observed for 4 h after LPS administration, and lung injury was evaluated by extravascular lung water, 125I-albumin leakage in lung tissue, and lung neutrophil accumulation. In the LPS alone group, rapid and sustained peripheral neutropenia (p < 0.001 versus saline at 15 min and at 1, 2, and 4 h), an increased plasma TNF-alpha concentration (p < 0.005 at 1 h), and increases in lung injury parameters (p < 0.05) were observed. In the LPS + B464 group, no changes were observed in either plasma TNF-alpha or lung injury parameters. Transient peripheral neutropenia and subsequent rapid recovery (p > 0.05, p < 0.001, p < 0.01, and p > 0.05 at 15 min and 1, 2, and 4 h, respectively) were observed in the LPS + B464 group. These in vivo data, together with in vitro evidence of suppressed cellular responses, suggest that B464 (1) inhibits neutrophil accumulation in lung tissue, and (2) attenuates the development of acute lung injury by blocking the activation of neutrophils and mononuclear cells as well as the interaction between neutrophils and endothelial cells.

[Effects of intravenous 2-chloroadenosine on endotoxin-induced acute lung injury]

To assess the effects of 2-chloroadenosine (2CA) on acute lung injury caused by endotoxin (lipopolysaccharide), guinea pigs were given 2CA intravenously. Three groups were used: saline control, endotoxin control and 2CA+ endotoxin. In the endotoxin and 2CA+ endotoxin groups, neutrophils accumulated in bronchoalveolar lavage fluid and in lung tissue. However, neutrophil accumulation did not differ significantly between the endotoxin and the 2CA+ endotoxin groups. The number of macrophages in bronchoalveolar lavage fluid was significantly higher in the endotoxin group than in the saline control group, but the difference between the saline control and the 2CA+ endotoxin groups was not significant. The lung wet-dry weight ratio and 125I-albumin lung tissue-plasma ratio, which were used to measure acute lung injury, were significantly higher in the endotoxin group than in the 2CA+ endotoxin and the saline control groups. However, these ratios did not differ between the 2CA+ endotoxin and the saline control groups. These results suggest that 2CA attenuated endotoxin induced acute lung injury in guinea pigs.

Augmentation of endotoxin-induced pulmonary responses by mononuclear cell phagocytosis in the reticuloendothelial system

OBJECTIVE

To test the hypothesis that the effects of intravenous injection of latex particles would demonstrate the contribution of phagocytosis by mononuclear phagocytes to the development of Escherichia coli-induced acute lung injury in neutropenic guinea pigs.

DESIGN

Prospective, controlled, experimental study. Intravenously injected the latex particles into 41 guinea pigs to investigate the contribution of the phagocytosis in acute lung injury.

SUBJECTS

Forty-one guinea pigs.

INTERVENTIONS

Forty-one guinea pigs were divided into five experimental groups: a saline group (n=9); an endotoxin group (n=10) receiving 2 mg/kg of intravenous E. coli endotoxin; a latex group (n=7) receiving 2 x 10(9)/kg of intravenous polystyrene latex (mean diameter 3.19 micrometers); an endotoxin + latex group (n=8); and an E. coli group (n=7) receiving 2 x 10(9) live E. coli/kg.

MEASUREMENTS AND MAIN RESULTS

The lung wet/dry ratio was increased in the live E. coli-treated guinea pigs (6.71 +/- 0.16 [SEM], p < .01) as compared with the saline control (5.40 +/- 0.16, whereas the ratio was not increased in the endotoxin (5.52 +/- 0.14) or latex (5.58 +/- 0.20) groups. However, the lung wet/dry ratio was greater in the endotoxin + latex group (6.11 +/- 0.16, p < .05) than in the saline control. The 125I albumin lung tissue/plasma ratio was greater in the E. coli (2.00 +/- 0.29, p < .01) and endotoxin + latex (0.84 +/- 0.12, p < .05) groups than in the saline group (0.18 +/- 0.07), whereas no increases were observed in the endotoxin group (0.22 +/- 0.10) and the latex (0.34 +/- 0.13) group. More than 40% of the injected radiolabeled latex was observed to have accumulated in the reticuloendothelial system (liver and spleen), in both the saline control (40.1 +/- 2.3%, n=4) and endotoxin (57.3 +/- 6.8%, n=5) groups, with 2.6 +/- 1.5% and 3.1 +/- 1.7% in the lungs for the saline control and the endotoxin groups, respectively. The percent deposition of radiolabeled latex in the liver was greater in the endotoxin group (51.7 +/- 3.8%, p < .05) than in the saline group (37.6 +/- 5.9%).

CONCLUSIONS

These findings suggest that, in neutropenic guinea pigs: a) the combination of endotoxin and latex particles induces acute lung injury; and b) the phagocytic properties of mononuclear phagocytes in the reticuloendothelial system augment endotoxin-induced pulmonary responses and may play a role in the development of live E. coli-induced acute lung injury.

Local Pseudomonas instillation induces contralateral lung injury and plasma cytokines

We investigated whether local bacterial instillation leads to lung injury in noninstilled lung regions and examined local and systemic cytokine accumulation. Rats were challenged by intrabroncheal instillation of Pseudomonas aeruginosa, 10(7) colony-forming units (CFU) (HD group, n = 11), 4 x 10(6) CFU (LD group, n = 10), or saline (control group, n = 12). 99mTc-labeled macroaggregated albumin was added to the P. aeruginosa or saline solution for later documentation of the instilled area. At 4 h the right lung, including instilled segment, and the left lung were sampled. Lung injury was assessed by lung tissue to plasma 125I-labeled albumin (T/P) and lung wet-dry (W/D) ratios. We measured plasma and bronchoalveolar lavage fluid (BALF) levels of tumor necrosis factor (TNF) and cytokine-induced neutrophil chemoattractant (CINC). HD bacterial instillation induced neutrophil recruitment and TNF and CINC elevation in BALF (p < 0.05) associated with increased T/P (p < 0.005) and W/D (p < 0.05) ratios in both instilled and the noninstilled lungs as compared with the saline-instilled and noninstilled controls. LD bacterial instillation induced neutrophil recruitment and TNF and CINC elevation only in the instilled lung (p < 0.05), and not in the noninstilled lung, and did not increase the T/P or W/D ratio. Plasma levels of TNF and CINC were increased in the HD, but not the LD, group when compared with the saline controls (p < 0.05). These data indicate that, when the dose is high enough to cause an excess inflammatory response, local bacterial instillation leads to neutrophil sequestration, lung injury, and cytokine elevation in the noninstilled lung associated with systemic cytokine release.

Heat-killed Corynebacterium parvum enhances endotoxin lung injury with increased TNF production in guinea pigs

Corynebacterium parvum (CP) is known to increase susceptibility to endotoxin, which is associated with increased production of tumor necrosis factor (TNF). We investigated the effect of CP-priming on the pathogenesis of acute lung injury caused by intratracheal Escherichia coli endotoxin (lipopolysaccharide [LPS]). Guinea pigs were divided into four groups: (1) control (n=6), (2) CP-alone (n=6), (3) LPS-alone (n=6) and (4) CP + LPS (n=6). A CP dose of 4 mg/kg was injected intraperitoneally 7 d before the study. Animals were observed for 4 h after intratracheal administration of 0.02 mg/kg of LPS. The lung wet-to-dry weight ratio (W/D), [125I] albumin concentration ratio of lung tissue to plasma (T/P) and of bronchoalveolar lavage (BAL) fluid to plasma (B/P) and differential cell count in BAL fluid were examined. In the LPS-alone group, neither excess lung water nor increased albumin leakage was observed. The CP + LPS group showed increased lung water and albumin leakage as compared with the other three groups (p<0.05). We also observed increased cell counts in BAL fluid (p<0.05), in the CP + LPS group. The spleen weight was increased in guinea pigs pretreated with CP, indicating reticuloendothelial system (RES) activation. In the CP + LPS group, the TNF level was increased in both plasma and BAL fluid. We conclude that pretreatment with CP enhances LPS-induced acute lung injury in parallel with increasing TNF production, which suggests that the activation of mononuclear phagocytes contributes to increased susceptibility to intratracheal endotoxin in guinea pigs.

Effect of a specific neutrophil elastase inhibitor, ONO-5046, on endotoxin-induced acute lung injury

Because excessive neutrophil elastase (NE) activity is involved in the pathogenesis of acute lung injury, we speculated that administering anti-NE might prevent lung injury. In a guinea pig model of acute lung injury induced by Escherichia coli endotoxin (lipopolysaccharide [LPS]), we investigated the effect of ONO-5046, a low-molecular-weight and specific inhibitor of NE. ONO-5046 produced concentration-dependent inhibition of guinea pig NE, whereas there were no inhibitory effects on neutrophil chemotaxis or the expression of adhesion molecules in endothelial cells. Detectable NE activity in bronchoalveolar lavage (BAL) fluid was present in the LPS-alone group. No NE activity in BAL fluid was detected in the LPS+ONO-5046 groups. Neutrophil counts in BAL fluid, the lung tissue wet to dry weight ratio, and the lung tissue or BAL fluid to plasma ratio of 125I-albumin were increased in the LPS-alone group as compared with the saline group (p < 0.05). In the LPS+ONO-5046 group, neutrophil counts in BAL fluid, the lung tissue wet to dry weight ratio and BAL fluid to plasma ratio of 125I-albumin were decreased as compared with the LPS-alone group (p < 0.05). These data suggest that ONO-5046 can attenuate LPS-induced acute lung injury.

[Pathophysiology and Diagnosis of the acute respiratory distress syndrome]

We studied methods for diagnosing the acute respiratory distress syndrome (ARDS) based on its characteristic abnormalities. A gamma-ray external counting method with Tc-99m human serum albumin revealed that pulmonary microvascular permeability was abnormally high in patients with ARDS. With this method, ARDS could be distinguished from cardiogenic pulmonary edema. Levels of interleukin-8 in bronchoalveolar fluid from patients with septic ARDS, reexpansion pulmonary edema, and inhalation burn injury were abnormally high. In 21 patients with acute lung injury, 15 of whom had ARDS, plasma concentrations of three inflammatory markers were measured: thiobarbituric acid reactive material which reflects cell membrane lipid peroxidation; 7S collagen, a component of basement membrane; and the soluble form of P-selectin, an adhesion molecule. Levels of all three were abnormally high in patients with ARDS, and correlated with the degree of lung injury and with the outcome in these patients. We conclude that these measurements in plasma or bronchoalveolar lavage fluid may enable us to assess the severity of ARDS.

Neutrophil-induced lung protection and injury are dependent on the amount of Pseudomonas aeruginosa administered via airways in guinea pigs

We investigated the roles of neutrophils in mediating both the protective effect against bacterial infection and the harmful effect of lung injury induced after the intratracheal instillation of live bacteria. We examined the mortality rate, lung injury, and bacterial clearance following the intratracheal instillation of Pseudomonas aeruginosa in low (10(4) colony-forming units [CFU]) and high doses (10(8) CFU) in normal (control) guinea pigs, others made neutropenic with cyclophosphamide (CPA), and guinea pigs made neutrophilic with recombinant granulocyte colony-stimulating factor (rG-CSF). Lung injury was assessed by the ratio of the concentration of 125I-labeled albumin in lung tissue to that in plasma (T/P) and the animals' lung weight-to-body weight (LW/BW) ratio. With 10(4) CFU, the CPA group showed an increased T/P ratio of 0.22 +/- 0.03 versus 0.14 +/- 0.01 in the control and 0.11 +/- 0.01 (mean +/- SEM) in the rG-CSF groups (p < 0.01). Viable bacteria were recovered from bronchoalveolar lavage fluid (BALF) in the CPA group. Neutrophil recruitment was observed in the lungs of animals in the control and rG-CSF groups. With 10(8) CFU, the mortality rate was increased in the rG-CSF group (7 of 10) as compared with the control (0 of 9) and CPA groups (1 of 9) (p < 0.05), which reflected an increased LW/BW (g/kg) ratio (16 +/- 2 versus 12 +/- 1) in the CPA group (p < 0.05). We conclude that neutrophils protect against lung injury during low-level bacterial challenge, but enhance lung injury and contribute to mortality during high-level bacterial challenge.

Effects of pretreatment with SDZ MRL 953, a novel immunostimulatory lipid A analog, on endotoxin-induced acute lung injury in guinea pigs

SDZ MRL 953 (SDZ), a novel immunostimulatory lipid A analog, has been reported to have immunopharmacological activities similar to those of lipopolysaccharide (LPS) but to have little of the toxicity of LPS. We investigated the effects of pretreatment with SDZ on Escherichia coli endotoxin-induced acute lung injury in guinea pigs. Four experimental groups consisted of saline control (n = 16), SDZ (-12 h) plus LPS (2 mg/kg of SDZ per kg of body weight injected intravenously 12 h before intravenous injection of 2 mg of LPS per kg; n = 15), SDZ (-10 min) plus LPS (SDZ injected 10 min before LPS injection; n = 10), and LPS alone (n = 16). The animals were sacrificed, and lung tissue was sampled 4 h after LPS or saline infusion. Lung injury was assessed by measuring the wet weight-to-dry weight ratio and the level of 125I-labeled albumin accumulation in bronchoalveolar lavage fluid relative to that in plasma. In the SDZ (-12 h) plus LPS group, these two parameters of acute lung injury were decreased compared with those in the LPS alone group. However, they were not decreased in the SDZ (-10 min) plus LPS group. We conclude that SDZ attenuates endotoxin-induced acute lung injury when it is administered 12 h before LPS injection. The attenuating effects of SDZ are speculated to be due to down regulation of the response to endotoxin rather than to receptor blocking.

Priming of alveolar macrophages for interleukin-8 production in patients with idiopathic pulmonary fibrosis

We evaluated the contribution of interleukin-8 (IL-8) to the pathogenesis of idiopathic pulmonary fibrosis (IPF) by studying bronchoalveolar lavage fluid (BALF) in eight patients with IPF in the chronically progressive phase, five patients with IPF in the subacutely progressive phase, eight patients with sarcoidosis (SAR), and eight control (CTL) subjects. IL-8 levels were not increased in the BALF of the patients with IPF in the chronic phase (11.3 +/- 8.8 pg/ml), nor in that of the SAR patients (13.8 +/- 7.8 pg/ml), whereas they were increased in the BALF of patients with IPF in the subacutely progressive phase (1.93 +/- 1.10 ng/ml). We then investigated extracellular and cell-associated IL-8 in lipopolysaccharide (LPS)-stimulated BALF cells to determine the IL-8-producing potential of alveolar macrophages (AM). Following LPS stimulation of BALF cells from patients with IPF in the chronic phase, both the extracellular IL-8 in culture fluid and the cell-associated IL-8 in AM were increased as compared with those for the CTL subjects (p < 0.05 and p < 0.05, respectively). These results suggest that AM of patients with IPF are primed for IL-8 production. We conclude that IL-8 may play a role in neutrophilic alveolitis, especially during the subacute phase of IPF.

[Effects of intravascular latex injection on factors responsible for acute lung injury]

To study the contribution of phagocytosis to the development of acute lung injury, latex particles (2 x 10(9)/kg; mean diameter, 2.84 microns) were injected intravenously or intra-arterially into guinea pigs. 125I-labelled albumin was injected to estimate the degree of lung injury, and 51Cr-labelled red blood cells were injected to correct for blood contamination in the samples. A control group was given saline. Four hours after the injections, the animals were killed, bronchoalveolar lavage was done, and the lungs were examined histopathologically. Animals that had received intravenous and intra-arterial injections of latex particles had more lung water and more pulmonary albumin leakage than animals that had received saline. Histopathological examination revealed massive accumulation of latex in the reticuloendothelial system. These findings suggest that the phagocytic process in the reticuloendothelial system plays a role in the development of lung injury in guinea pigs.

BCG priming enhances endotoxin-induced acute lung injury independent of neutrophils

Bacillus Calmette Guérin (BCG) is known to increase susceptibility to endotoxin in some animal species. We investigated the effect of BCG-priming and the role of neutrophils in the priming process on the pathogenesis of acute lung injury caused by intravenously administered Escherichia coli endotoxin (LPS). Guinea pigs were divided into seven groups: (1) control (n = 8), (2) BCG-alone (n = 6), (3) cyclophosphamide (CPA)-alone (n = 6), (4) CPA+LPS (n = 6), (5) LPS-alone (n = 6), (6) BCG+LPS (n = 6), and (7) BCG+CPA+LPS (n = 6). A BCG dose of 8 mg/kg was injected subcutaneously 10 d before the study. CPA was administered intraperitoneally to induce peripheral neutropenia. Animals were observed for 4 h after intravenous administration of 0.2 mg/kg of LPS. The plasma TNF level was measured 2 h after LPS challenge. Lung wet-to-dry weight ratio, [125I] albumin leakage in lung tissue, differential cell count in bronchoalveolar lavage (BAL) fluid, and histopathologic features were examined immediately after death. Although the LPS-alone group showed PMN accumulation in lung tissue, neither excess lung water nor increased albumin leakage was induced by this dose of LPS. The BCG+LPS group showed increased lung water, histopathologic edema, and increases in BAL fluid cell counts and plasma TNF in comparison with the LPS-alone group. The BCG+CPA+LPS group also showed enhanced lung injury comparable to that seen in the BCG+LPS group. In both the CPA-alone and the CPA+LPS groups, no parameter was increased as compared with those in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

[A case of large cell carcinoma of the lung arising from the inner surface of a pulmonary bulla and complicated by hematoma]

A 64-year-old man with a history of smoking was admitted to our hospital, because he was noted to have a solitary mass lesion at the apex of the right lung on a chest roentgenogram. Eight months before admission, he had come to our hospital because of hemoptysis. At that time, however, no abnormal shadow was seen on his chest roentgemogram, except for multiple bullae at both apexes. Based on chest CT findings on admission, the tumor appeared to be a hematoma growing inside the bulla. The resected tumor was found to contain a large amount of coagulated blood in the bulla. Histopathological examination of the bulla revealed a proliferation of large atypical cells from the inner surface of the bulla toward the inner space. Thus, the diagnosis was large cell carcinoma within the wall of the pulmonary bulla, the inside of which was filled with hematoma. We believe that the hematoma in the bulla allowed us to make an early diagnosis, and thus to succeed in curing the patient.

Soluble form of P-selectin in plasma is elevated in acute lung injury

A number of adhesion molecules on neutrophils and the pulmonary capillary endothelium mediate the neutrophil accumulation in the lungs at the onset of adult respiratory distress syndrome or acute lung injury (ALI). P-selectin, located on both vascular endothelial cells and platelets, has been shown to be one of these neutrophil-endothelial cell adhesion molecules. In this study, we measured the soluble form of P-selectin in plasma (PPS) from 19 patients (surviving, 11; deceased, 8) with ALI due to various causes and assessed the clinical significance of this measurement. Twelve healthy subjects and 29 patients with other pulmonary diseases, including idiopathic pulmonary fibrosis (IPF) (n = 8), sarcoidosis (n = 5), pneumonia (n = 8), and sepsis without ALI (n = 8) were also studied for comparison. PPS in patients with ALI (474.5 +/- 366.8 ng/ml, mean +/- SD) were significantly higher than those in control subjects (98.8 +/- 39.7, p < 0.01) and in patients with IPF (210.4 +/- 76.6, p < 0.05), sarcoidosis (135.2 +/- 71.5, p < 0.05), pneumonia (225.3 +/- 81.0, p < 0.05), and sepsis without ALI (271.8 +/- 46.5, p < 0.05). There was no significant difference in PPS levels between seven patients with and 12 patients without multiple organ failure. Lung injury scores correlated significantly with the PPS level (r = 0.605, p < 0.05). PPS levels of deceased patients with ALI (841.0 +/- 252.4) were significantly higher than those of surviving patients with ALI (208.0 +/- 109.2, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Attenuation of hyperoxic lung injury by the 21-aminosteroid U-74389G

Hyperoxic lung injury is attributable to oxygen radicals produced under hyperoxic conditions. The 21-aminosteroid (AS), U-74389G, is a potent antioxidant. We examined the effect of U-74389G on lung injury in guinea pigs during exposure to 90% O2 for 48 h. We injected either vehicle or 10 mg/kg of U-74389G 30 min before the O2 exposure and injected the same dose 12, 24, and 36 h later. We performed two series of experiments after exposure. In the first series, we measured the clearance rate of 99mTc-labeled dialdehyde starch (DAS) from the lungs as an index of pulmonary epithelial damage in three experimental groups consisting of 1) control (n = 6) O2 alone (n = 6), and 3) O2 + AS (n = 6). In the second series, pulmonary endothelial injury was estimated by using 28 guinea pigs divided into four experimental groups consisting of 1) control (n = 8), 2) AS alone (n = 5), 3) O2 alone (n = 6), and 4) O2 + AS (n = 9). In the second series, we measured the wet-to-dry weight ratio (W/D) as an index of lung water and the concentration ratio of 125I-labeled albumin in lung tissue and bronchoalveolar lavage (BAL) fluid compared with plasma (T/P and BAL/P, respectively) as indexes of pulmonary endothelial damage. Cell accumulation in BAL fluid and lung tissue samples was also assessed in the second series.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of ONO-1078, a peptide leukotriene antagonist, on endotoxin-induced acute lung injury

The role of lipoxygenase metabolites in the pathogenesis of endotoxin (LPS)-induced lung injury remains to be clarified. We investigated the contribution of peptide leukotrienes to LPS-induced acute lung injury using a potent antagonist, ONO-1078 (ONO). Experimental groups consisted of a saline group (n = 10), an LPS group (n = 9) injected intravenously with 2 mg E. coli LPS, an ONO group (n = 8) receiving 30 mg/kg of intraperitoneal ONO, and an LPS+ONO group (n = 6) receiving 30 mg/kg of ONO intraperitoneally 10 min before the LPS injection. The [125I]albumin lung plasma ratio, which is a parameter of acute lung injury, was significantly increased (p < 0.01) in the LPS group compared with the saline, ONO, and LPS+ONO groups. The [125I]albumin BAL fluid plasma ratio was also increased (p < 0.01) in the LPS group compared with the other groups. ONO pretreatment attenuated the LPS-induced increases in neutrophil counts in the BAL fluid. In vitro studies showed that ONO suppresses the neutrophil chemotaxis induced by LTB4, zymosan-activated serum, and FMLP. We conclude that (1) ONO-1078 attenuates LPS-induced acute lung injury; and (2) this effect appears mainly a result of its potent antagonistic actions against peptide leukotrienes and also, in part, the suppression of neutrophil chemotaxis.

Pulmonary infection due to Mycobacterium xenopi

We describe two cases of pulmonary infection due to Mycobacterium xenopi (M. xenopi). Both cases were men, ages 61 and 54 yr. In the first patient, lung infection due to M. xenopi occurred after gastrectomy. The second patient had an inactive M. tuberculosis infection. Both had pulmonary symptoms including cough, sputum and fever. Each chest X-ray showed an infiltrative shadow with a cavity in a unilateral, upper lobe. Isolates from both patients were studied not only by microbiological characteristics but also by DNA-DNA hybridization. All isolates were susceptible to streptomycin and kanamycin. In the first case, the patient had initially received rifampicin, isoniazid and ethambutol despite in vitro susceptibility patterns, however, there was no response and a new infiltrative shadow appeared in the contralateral lobe. With a multiple drug regimen based on in vitro susceptibility, clinical and roentgenographic improvements were achieved. The second patient showed a favorable response to the initial chemotherapy. Pulmonary infection due to M. xenopi can generally be successfully treated with drugs to which the organisms show in vitro sensitivity. We also reviewed the other two cases reported in Japan.

Regional lung hematocrit variation and assessment of acute lung injury

Estimating blood content in the lung remains a key step in calculating lung water volume and microvascular permeability. We studied the effect of regional lung hematocrit (Hct) variation on assessment of acute lung injury. Escherichia coli endotoxin was administered in guinea pigs intravenously. Lung injury was evaluated by measuring the wet-to-dry weight ratio (W/D) and transvascular 125I-labeled albumin leakage for 3 h [tissue-to-plasma 125I-albumin ratio (T/P)] in five tissue samples from each animal. Residual blood content was corrected using either 51Cr-red blood cells as a blood cell marker, 99mTc-albumin as a plasma marker, or both, injected 10 min before the guinea pigs were killed. Lung Hct, estimated from the marker counts of lung and peripheral blood samples, was lower than peripheral blood Hct; intraindividual variation, represented by the standard deviation in each subject, was 0.024 +/- 0.015 for the control group (coefficient of variation 8.0 +/- 5.1%) and 0.026 +/- 0.013 for the endotoxin group (coefficient of variation 8.5 +/- 4.1%). Uncorrected W/D for residual blood content was greater than the corrected W/D. 99mTc-albumin correction gave values closer to the W/D corrected by both markers. T/P corrected by 99mTc-albumin showed smaller data variations than the values obtained with 51Cr-red blood cell correction, which was affected by variations in lung Hct. We recommend using a plasma marker to correct for blood content in assessing acute lung injury by W/D and T/P.