Do adhesion molecules importantly regulate leukocyte kinetics within intraacinar microvessels of the lung?

Precise assessment of blood cell kinetics in the pulmonary microcirculation is extremely difficult because pulmonary microvascular architecture contains arterioles, venules and capillaries in an exceedingly intricate and densely convoluted fashion. Conventional epiluminescence microscopy may not be suitable for investigation of blood cell kinetic in the pulmonary microcirculation, in which arterioles, venules and capillary networks are not located in the same plane. To overcome these impediments, we recently developed a real-time confocal laser luminescence microscope with a high-speed analysis component having the capacity to yield confocal-images of rapidly moving cells at a rate of 1,000 frames/sec and at sufficiently high magnification. In the current review, we will first introduce the details of our newly developed observation system constructed with a view to estimation of blood cell dynamics in the intraacinar microcirculation of the lung. Applying this novel method to isolated perfused rat lungs, we will secondly address the issue of whether or not leukocyte-endothelium interactions in the pulmonary microcirculation qualitatively differ from those serving in the systemic microcirculation. We will particularly shed light on possible roles of endothelial ICAM-1, endothelial P-selectin and leukocyte L-selectin in distorting leukocyte kinetics in the intraacinar microvessels under a variety of diseased conditions, including prolonged exposure to a hyperoxic environment inducing a significant upregulation of ICAM-1 as well as P-selectin on the pulmonary microvascular endothelium, and stimulation of leukocytes by an IL-8 analog causing downregulation of leukocyte L-selectin but inverse upregulation of CD18-related integrins.

Impaired hypoxic vasoconstriction in intraacinar microvasculature in hyperoxia-exposed rat lungs

To assess the effects of exposure of the lung to hyperoxic conditions on reactivity of pulmonary microcirculation to hypoxic stimulation, we measured hypoxia-elicited overall pulmonary pressor changes (HPV) and microvascular diameter changes in intraacinar arterioles, venules, and capillaries in isolated perfused rat lungs exposed to a hyperoxic environment (90% O2). To estimate the importance of vasoactive prostaglandins and nitric oxide (NO) for HPV modification, we examined the roles of constitutive and inducible forms of cyclooxygenase (COX-1 and COX-2) and those of NO synthase (eNOS and iNOS). Indomethacin was used for inhibiting both COX-1 and COX-2, while NS-398 was used as a selective inhibitor of COX-2. Both eNOS and iNOS were suppressed by L-NAME, whereas iNOS alone was inhibited by aminoguanidine. Microvascular diameter was measured with a real-time confocal laser scanning luminescence microscope. We found that (1) exposure to hyperoxia caused overall HPV and arteriolar constriction to be attenuated; (2) the blunted HPV was restored by L-NAME but not by aminoguanidine, indomethacin, or NS-398; and (3) arteriolar constriction was improved by either L-NAME, aminoguanidine, or indomethacin but only slightly by NS-398. In conclusion, attenuation of overall HPV in hyperoxia-exposed lungs is explicable mainly by excessive NO generated via eNOS, while impaired arteriolar constriction is caused by NO yielded by eNOS and iNOS as well as by vasodilating prostaglandin(s) produced by COX-1.

Response of intra-acinar pulmonary microvessels to hypoxia, hypercapnic acidosis, and isocapnic acidosis

To elucidate the differential reactivity of pulmonary microvessels in the acini to hypoxia, excessive CO2, and increased H+, we investigated changes in the diameter of precapillary arterioles, postcapillary venules, and capillaries in isolated rat lungs on exposure to normocapnic hypoxia (2% O2), normoxic hypercapnia (15% CO2), and isocapnic acidosis (0.01 mol/L HCl). Microvascular diameters were precisely examined using a real-time confocal laser scanning luminescence microscope coupled to a high-sensitivity camera with an image intensifier. Measurements were made under conditions with and without indomethacin or N(omega)-nitro-L-arginine methyl ester to assess the importance of vasoactive substances produced by cyclooxygenase (COX) or NO synthase (NOS) as it relates to the reactivity of pulmonary microvessels to physiological stimuli. We found that acute hypoxia contracted precapillary arterioles that had diameters of 20 to 30 microm but did not constrict postcapillary venules of similar size. COX- and NOS-related vasoactive substances did not modulate hypoxia-elicited arteriolar constriction. Hypercapnia induced a distinct venular dilatation closely associated with vasodilators produced by COX but not by NOS. Arterioles were appreciably constricted in isocapnic acidosis when NOS, but not COX, was suppressed, whereas venules showed no constrictive response even when both enzymes were inhibited. Capillaries were neither constricted nor dilated under any experimental conditions. These findings suggest that reactivity to hypoxia, CO2, and H+ is not qualitatively similar among intra-acinar microvessels, in which COX- and NOS-associated vasoactive substances function differently.

[Pulmonary emphysematous changes associated with Pneumocystis carinii pneumonia in an AIDS patient]

A 60-year-old man was admitted to our hospital complaining of non-productive cough. He had worked in Africa and received a blood transfusion after a traffic accident in 1985. On admission, the patient had remarkable hypoxemia and a decreased CD4+ lymphocyte count. A serological test for human immuno-deficiency virus (HIV)-1 was positive. His chest radiographs showed diffuse reticular and linear opacities, and broncoalveolar lavage findings established a diagnosis of Pneumocystis carinii pneumonia (PCP). A high-resolution CT of the chest revealed peripheral infiltrates and low attenuation areas (LAA) consistent with severe emphysematous alterations. We administered high-dose methylprednisolone and trimethoprim-sulphamethoxazole (TMP-SMX). Because of marked eosinophilia, TMP-SMX was discontinued, and the patient was given inhaled pentamidine isothiocyanate. Although there was a striking clinical improvement, the emphysema-like lesion on chest CT remained unaltered. LAA on CT had been modest in 1994, but had markedly enlarged during the three years thereafter, leading us to speculate that most of the LAA lesions recognized on admission might have developed in association with PCP. Pulmonary function tests showed an obstructive ventilatory defect and impaired diffusing capacity. Although PCP classically presents with diffuse ground-glass or fine granular opacities, thin-walled cavities or other atypical findings have recently been reported, especially in AIDS patients. There have been several reports about emphysema-like lesions associated with PCP. It was suggested that these lesions might be due to lung parenchyma destruction induced by HIV itself or increased elastase release from HIV-infected macrophages. This is the first report of PCP with pulmonary emphysematous lesions in Japan.

Differential contribution of various adhesion molecules to leukocyte kinetics in pulmonary microvessels of hyperoxia-exposed rat lungs

To elucidate the differential role of various adhesion molecules in distorting leukocyte behavior in the microvasculature of hyperoxia-exposed rat lungs, we investigated fluorescein-labeled leukocyte and erythrocyte kinetics in isolated lungs taken from the animals exposed to 90% O2 for 48 h under conditions in which endothelial intercellular adhesion molecule-1 (ICAM-1) and P-selectin were inhibited by appropriate monoclonal antibodies (1A29 for ICAM-1 and ARP2-4 for P-selectin), while leukocyte L-selectin was restrained with fucoidin. Measurements of blood cell kinetics were made by a confocal laser luminescence microscope coupled with a high-speed video camera. In addition, we histologically examined leukocyte accumulation within the alveolar septa and ICAM-1 as well as P-selectin expressions in the lung. We found that P-selectin expression was sparsely enhanced only in arterioles, whereas ICAM-1 was significantly induced in both venules and capillaries. Firm adhesion of leukocytes was not identified in arterioles and venules, whereas leukocyte rolling was evident in both the vessels. Arteriolar rolling was regulated via a P-selectin- and ICAM-1-independent but L-selectin-dependent mechanism, whereas venular rolling was mediated via a P-selectin-independent but ICAM-1- and L-selectin-dependent pathway. Leukocyte sequestration within capillaries was augmented by an ICAM-1-related mechanism. These findings may suggest that, in hyperoxia-exposed lungs, induction of adhesion molecules and their obstacles to leukocyte behavior are qualitatively different among arterioles, venules, and capillaries.

[Acute exacerbation of subacute interstitial pneumonia after thoracoscopic lung biopsy]

A 55-year-old woman was admitted to our hospital with progressive dyspnea that had begun one month before. Chest rentogenogram revealed groundglass appearance and reticular shadows bilaterally. Pulmonary function tests showed both decreased vital capacity and diffusing capacity. Bronchoalveolar lavage fluid had a high lymphocyte fraction with a low CD4+/CD8+ ratio. Thoracoscopic lung biopsy revealed thick, fibro-edematous interstitium and diffuse infiltration of lymphocytes. We also observed an intra-alveolar exudate with infiltration of histiocytes and lymphocytes. The clinical features and pathological findings were consistent with subacute interstitial pneumonia, which was the entity proposed by Kawabata and colleagues. The patient developed acute respiratory failure four days after lung biopsy and died despite steroid pulse therapy. Although subacute interstitial pneumonia has been reported to respond to steroid therapy, and to have a good prognosis, we believe that subacute interstitial pneumonia could fatally worsen when associated with lung biopsy, infection, or some other stimulus.

[A case of interstitial pneumonia induced by intravesical administration of bacillus Calmette-Guerin (BCG)]

A 61-year-old man with superficial bladder cancer, which was detected after he complained of hematuria, was treated three times with intravesical BCG administration. Since liver dysfunction was detected thereafter, he was admitted to our hospital. Three days after admission, he complained of dyspnea on exertion associated with severe hypoxemia, as well as abnormal findings on chest X-ray, i.e. extensive bilateral lung densities. We performed bronchoscopic examination and obtained bronchoalveolar lavage fluid (BALF) and lung biopsy specimens (TBLB). In the BALF, a marked increase in the total cell number, particularly lymphocytes with a high CD4/CD8 ratio was noted. TBLB specimens revealed the lesions to be numerous non-caseating granulomas. We failed to obtain definite evidence of BCG in the sputum, urine, blood, and BALF. Instead, we found that a lymphocyte stimulation test for BCG (DLST) was strongly positive. Based on these findings, severe interstitial pneumonia probably induced by hypersensitivity against BCG, was diagnosed. Anti-tuberculous agents, and steroid-pulse therapy followed by oral administration of relatively low dose of steroid ameliorated the abnormal conditions, including chest X-ray film findings and hypoxemia. The population of lymphocytes and CD4/CD8 ratio in the BALF were reduced as well. Serious interstitial pneumonia was induced by the intravesical administration of BCG, which resulted in transitional changes in the BALF cell component.

Role of CD18-ICAM-1 in the entrapment of stimulated leukocytes in alveolar capillaries of perfused rat lungs

This study aimed to examine the behavior of stimulated leukocytes in the pulmonary microcirculation. The leukocyte-endothelium interaction was visualized under physiological shear rates in perfused rat lungs using high-speed confocal laser video microscopy. Leukocytes labeled with carboxyfluorescein were stimulated with cytokine-induced neutrophil chemoattractant (CINC/gro), which caused L-selectin shedding and inverse upregulation of CD18. Neither unstimulated nor stimulated leukocytes exhibited rolling in either pulmonary arterioles or venules, whereas both were sequestered in capillaries. Approximately 50% of stimulated leukocytes showed a transient cessation of movement in pulmonary capillaries. The CINC/ gro stimulation, which inhibited leukocyte rolling and adhesion to mesenteric venules, reduced leukocyte velocity and increased leukocytes in pulmonary capillaries. Pretreatment with monoclonal antibodies against intercellular adhesion molecule-1 (ICAM-1) or CD18 attenuated these changes. Confocal microfluorography revealed constitutive expression of ICAM-1 not only in venules but also abundantly in capillary networks. These results suggest that selectin-independent, CD18-ICAM-1-dependent capillary sequestration is one of the major mechanisms by which activated leukocytes accumulate in the lungs.

Effects of active vasoconstriction and total flow on perfusion distribution in the rabbit lung

We analyzed the effects of hypoxic vasoconstriction and total flow on the distribution of pulmonary perfusion in 38 isolated left rabbit lungs perfused under zone 3 conditions. Lungs were suspended in an upright position, oriented to the apicobasal line. Distributions of regional perfusion rates (RPR) along the vertical and horizontal axes were determined using nonradioactive microspheres labeled with heavy metal elements, which were detectable with X-ray fluorescence spectrometry. Changing the O2 concentration of a respirator and an extracorporeal membrane oxygenator independently, respective influences of active vasoconstriction induced by alveolar hypoxia and pulmonary artery hypoxia (PA hypoxia) on the RPR distribution were examined at a flow rate of 0.4 ml x min(-1) x g wet lung tissue(-1). To analyze the effects of changes in total flow, we investigated the RPR distribution at a perfusion rate of 1.2 ml x min(-1) x g wet lung tissue(-1). The RPR distribution in the absence of hypoxia was inhomogeneous and was augmented in the lower lung fields, whereas alveolar hypoxia shifted the RPR upward and significantly diminished the RPR in the lung base. RPR distributions along the horizontal axes under alveolar hypoxia conditions demonstrated that remarkable hypoxic pulmonary vasoconstriction (HPV) takes place in medial regions at the lung base. PA hypoxia altered the RPR distribution in qualitatively the same manner as alveolar hypoxia. Increased flow rate augmented the RPR in the lung, except in the dorsobasal region. These results suggest that the occurrence of HPV and the vascular conductance are not uniform throughout the lung.

[Normal predicted values of CT indices reflect emphysematous alterations in the lung]

In order to obtain normal values and 95% confidence limits of various CT indices, healthy adult subjects with no history of smoking (n = 36) underwent CT scanning under a variety of conditions. By then applying the normal limits thus obtained to CT images of COPD patients (n = 45), we examined the sensitivity for detecting abnormal emphysematous changes in the lung fields. To measure emphysematous alterations, we used the average value of lung CT densities (ROI), the maximally appearing value in a CT histogram (Hist. Peak), the relative area with low CT densities below -910 HU (%LDA) and the total cross-sectional area (Area) in each lung section. Regardless of the section thickness (10 mm or 1 mm), the lung volume level at which the breath was held or the site from which CT images were taken (upper, middle or lower lung field), no significant correlation was observed between the CT indices associated with emphysematous changes and the subjects' age. This allowed us to define, independently of the subjects' age, normal values and 95% confidence limits for the CT indices. Among the CT indices surveyed, %LDA was found to be the most sensitive indicator for detecting emphysematous abnormalities. In so far as the extent of emphysema may be determined by lung CT density, classical CT images of 10-mm section thickness appear to have a sufficiently high sensitivity for the detection of emphysematous abnormalities, such that high-resolution CT may be unnecessary.

Inhomogeneities of ventilation and the diffusing capacity to perfusion in various chronic lung diseases

Although impairment of gas exchange caused by ventilation-perfusion (VA/Q) mismatch has been extensively analyzed, there have been no systematic studies focused on determining the distributions of diffusion properties in dose connection with those of VA/Q. We attempted to clarify the simultaneous distributions of VA/Q and diffusion capacity to perfusion (D/Q) in patients with idiopathic pulmonary fibrosis (IPF) or chronic obstructive pulmonary disease (COPD). To assess pathologic determinants causing functional abnormalities, we compared VA/Q and D/Q distributions with the findings on high-resolution computed tomography. O2, CO2, and CO together with six foreign inert gases were used as indicator gases. We transformed the measured data on indicator gases in arterial blood into a continuous distribution of Q in the VA/Q-D/Q field. In IPF, active alveolitis or acinitis played a major role in producing low D/Q regions impeding gas exchange via a diffusion limitation, whereas extensive fibrosis with minimal inflammation accounted for low D/Q as well as low VA/Q regions. In COPD, no regions with low D/Q ratios were observed, but an abnormality in the VA/Q distribution with low or high VA/Q ratios was identified. Emphysematous lesions produced high VA/Q regions, whereas peripheral airway involvement yielded low VA/Q regions. These findings suggest that hypoxemia in patients with IPF is caused by inhomogeneous distributions of D/Q in combination with those of VA/Q. Hypoxemia in patients with COPD is attributable primarily to inhomogeneities in VA/Q rather than in D/Q distributions.

Leukocyte kinetics in the pulmonary microcirculation: observations using real-time confocal luminescence microscopy coupled with high-speed video analysis

To quantitatively assess blood cell kinetics in the intact pulmonary microcirculation, in which arterioles, venules, and capillaries are exceedingly intricate and densely convoluted, we recently developed a real-time confocal laser luminescence microscope with a high-speed analysis component. The system has the capacity to yield confocal images of rapidly moving cells at a rate of 1000 frames/second and at sufficiently high degrees of magnification. Applying this novel method to isolated perfused rat lungs, we estimated the endothelial distributions of constitutively expressed intercellular adhesion molecule-1 (ICAM-1) and P-selectin and also studied leukocyte hemodynamic behavior in the pulmonary microvasculature under conditions in which ICAM-1, P-selectin, and L-selectin were inhibited, respectively, by 1A29 (monoclonal antibody to rat ICAM-1), ARP2-4 (monoclonal antibody to rat P-selectin), and fucoidin (competitive inhibitor of both P- and L-selectin). The results were compared with those obtained with a nonconfocal microscope using conventional epiluminescence. Intertwined microvessel networks in the lung were clearly distinguishable in confocal images but not in conventional nonconfocal views. ICAM-1 was perceptibly expressed along venular and capillary but not arteriolar endothelium, whereas P-selectin was undetectable in all microvessels examined. Leukocytes were not firmly adhered to venular or arteriolar endothelial cells. Leukocyte rolling was recognized more frequently along arteriolar walls than along venular walls and was suppressed in arterioles by L-selectin inhibition but not by either ICAM-1 or P-selectin inhibition. In capillaries, transient and sustained arrest of leukocytes occurred at physiologic shear rates. Inhibition of ICAM-1 or P-selectin had no remarkable effect upon either transient or sustained entrapment of leukocytes in capillaries. In conclusion, physiologic and biologic characteristics of pulmonary microvessels appear to be quite different from those of the systemic microcirculation.

Effect of hyperoxia on adhesion molecule expression in human endothelial cells and neutrophils

To investigate the pathogenesis of pulmonary oxygen toxicity, we examined the effect of hyperoxia on adhesion molecule expression in cultured human pulmonary artery endothelial cells (HPAEC) and human umbilical vein endothelial cells (HUVEC). Endothelial cell monolayers were exposed to either hyperoxic (90% O(2)-5% CO(2)) or normoxic (21% O(2)-5% CO(2)) conditions for various periods. The level of intercellular adhesion molecule (ICAM)-1 expression had increased in hyperoxia-exposed HPAEC and HUVEC at 48 h (194 +/- 38 and 233 +/- 56%, respectively; P < 0.001) and at 72 h (200 +/- 43 and 223 +/- 52%, respectively; P < 0.001) compared with normoxic conditions. These hyperoxia-induced ICAM-1 expressions were dose dependently attenuated by a protein kinase C inhibitor (H-7). In contrast, the levels of P-selectin and E-selectin expression in HPAEC and HUVEC were unchanged. The levels of ICAM-1 mRNA and the numbers of adherent neutrophils were increased in HPAEC and HUVEC at 48 and 72 h of hyperoxia. On the other hand, hyperoxia caused neutrophil H(2)O(2) production without affecting the level of CD11/CD18 expression. These results suggest that increased ICAM-1 expression in endothelial cells plays an important role in neutrophil accumulation during hyperoxia.

[Effects of hyperoxia on the behavior of leukocytes in rat pulmonary microcirculation assessed by confocal laser scanning microscopy]

To study the dynamic interaction between blood cells and endothelial cells in the pulmonary microcirculation, we developed a method for observing leukocytes and erythrocytes in the microcirculation of perfused rat lungs by confocal laser scanning microscopy. We examined the behavior of leukocytes in the microcirculation of rat lungs exposed to hyperoxia, because oxygen toxicity is known to be associated with leukocyte infiltration and endothelial cell damage. Rats were divided into two groups: control (21% O2) and hyperoxia (90% O2 for 48 hours). Lungs were perfused with Krebs-Henseleit solution equilibrated with 21% O2 and 5% CO2 through an artificial lung. Leukocytes stained with carboxyfluorescein diacetate succinimidyl ester and erythrocytes stained with fluorescein isothiocyanate were added to the perfusate, and images of the cells were observed and recorded with a confocal laser scanning microscope and a high-speed video camera. The mean velocities of erythrocytes (Vr) in arterioles, capillaries, and venules of the control group were 1.52, 0.50 and 1.61 mm/sec, respectively. Also in the control group, the velocities of the leukocytes were divided by the mean velocities of the erythrocytes in the same arterioles, capillaries and venules (Vw/Vr) and the results were 0.96, 0.97, and 0.98, respectively. The Vw/Vr values for arterioles in the hyperoxia group were not significantly different from those in the control group, but the Vw/Vr values for capillaries and venules were 27% and 37% lower than their respective control values. Leukocyte sequestration was seen mainly in capillaries in the hyperoxic group. These results suggest that an increase in adhesion in capillaries and venules, such as that caused by adhesion molecules, might play a key role in the behavior of leukocytes in the pulmonary microcirculation during hyperoxia.

Fatal diffuse alveolar damage from bird fanciers' lung

A 68-year-old man, who had continuing exposure to budgerigars, developed fatal acute respiratory failure following years of slowly progressive pulmonary deterioration. His lung function was characterized first by mild airflow obstruction and later by progressive loss of lung volume. Computed tomography showed progressive development of pulmonary fibrosis and honeycombing. His serum disclosed precipitins to pigeon antigen. During his final illness his chest radiograph showed widespread patchy consolidation. At autopsy, his lungs revealed left lower lobe bronchopneumonia, fibrosis and honeycombing at the bases and widespread evidence of diffuse alveolar damage with organized exudate in some alveoli. To our knowledge, this is the second reported fatality due to acute alveolar injury in bird fanciers' lung.

Mixed-cryoglobulinemia associated with cutaneous vasculitis and pulmonary symptoms

A 45-year-old Japanese man with Sjögren's syndrome developed recurrent skin ulcers, palpable purpura, and dyspnea. Serum mixed-type cryoglobulin level was elevated. A biopsy of his skin lesion showed the characteristic leukocytoclastic vasculitis of mixed-type cryoglobulinemia. Dyspnea, skin ulcers, and purpura resolved along with a reduction in the serum cryoglobulin level after prednisolone administration. This patient demonstrated cryoglobulinemia-associated vasculitis, as well as possible cryoglobulinemia-associated pulmonary symptoms.

Temporal alterations of endothelial-vasodilator functions in lung injury induced by monocrotaline

To assess the time course of alterations in pulmonary endothelial vasodilator functions during pathological development of pulmonary hypertension (PH) and right ventricular hypertrophy (RVH), we examined changes in serotonin (5-HT) removal rates and the production of prostacyclin (PGI2) and nitric oxide (NO) in isolated rat lungs harvested at various times after single exposure to monocrotaline (MCT). We assessed the generation of vasodilator substances under conditions of both the absence and the presence of 5-HT in lungs perfused with blood-free solution. Major findings included: (i) remodeling of the pulmonary vasculature associated with RVH evident 14 days after MCT injection; (ii) the capacity for 5-HT removal was suppressed at day 1 and 7 but had been restored by day 14 after MCT exposure; (iii) basal PGI2 production in the absence of 5-HT was augmented at day 1 but had returned to control levels in lungs harvested 7 or 14 days postinjection of MCT; (iv) PGI2 production evoked by 5-HT was suppressed in MCT lungs obtained at all time points examined; (v) basal NO production was suppressed at day 1 but enhanced at day 7 and 14 in MCT lungs; (vi) NO production elicited by 5-HT stimulation in 1-day-MCT lungs was obviously suppressed while that in 7- and 14-day-MCT lungs had been restored to the control level. These findings suggest that transitional changes in endothelial functions including 5-HT removal and production of vasodilators in MCT lungs do not follow the same time course.

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

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

[Indices allowing early detection of chronic pulmonary emphysema]

To establish criteria allowing early detection of pathologically significant alterations in pulmonary emphysema caused by smoking, pulmonary-function tests and high-resolution computed tomography were done in 104 subjects categorized into three groups: nonsmoking healthy adults, smokers with a normal FEV1%, and smokers with a low FEV1% (cross-sectional analysis). Fifty-six of the 104 patients underwent pulmonary-function testing and high-resdution computed fomography once per year for 3 years (longitudinal analysis). Cross-sectional and longitudinal analyses showed that abnormalities in functional residual capacity, in single-breath diffusing capacity for carbon monoxide, and in the average tomographic density of sections in the lower lung fields obtained after a deep inspiration could be used to predict whether the disease would reach an advanced stage, even if the patients had no significant symptoms at the time of testing. Relative areas of low-attenuation regions, which were alleged to directly reflect the size of emphysematous areas, appear not to be useful for early detection of pathological emphysema.

Modulation of ICAM-1 expression by extracellular glutathione in hyperoxia-exposed human pulmonary artery endothelial cells

To investigate the mechanisms regulating hyperoxia-induced intercellular adhesion molecule-1 (ICAM-1) expression, we studied the effects of antioxidants on ICAM-1 expression, and the relationship between ICAM-1 expression and extracellular glutathione levels in human pulmonary artery endothelial cells (HPAEC) and human umbilical vein endothelial cells (HUVEC). Cells were cultured to confluence and exposed to hyperoxia (90% O2) for 48 h with or without various antioxidants, including superoxide dismutase (SOD), catalase, N-acetylcysteine (NAC), and glutathione. The levels of ICAM-1 expression in the endothelial cells and the concentrations of reduced (GSH) and oxidized glutathione (GSSG) in the media were examined by flow cytometry and spectrophotometry, respectively. After exposure to hyperoxia, ICAM-1 expression was increased, and the supernatant total glutathione was decreased as compared with those at normoxia. SOD did not change ICAM-1 expression. The hyperoxia-induced increase in ICAM-1 expression was even greater with the addition of catalase. The ICAM-1 expression was decreased and the GSH concentration was increased with the addition of NAC. There were negative relationships between the level of ICAM-1 expression and the supernatant total glutathione concentration in catalase-treated HPAEC (R = 0.822, P < 0.0005) and HUVEC (R = 0.567, P < 0.01). Negative relationships were also demonstrated between the level of ICAM-1 expression and the total extracellular glutathione concentrations in NAC-treated HPAEC (R = 0.877, P < 0.0005) and HUVEC (R = 0.727, P < 0.0005). Exogenous GSH decreased ICAM-1 expression in both hyperoxia-exposed HPAEC and HUVEC, while exogenous GSSG did not. These results suggest that extracellular GSH plays a role in regulating hyperoxia-induced ICAM-1 expression in HPAEC and HUVEC.

[Abnormalitis in the distributions of ventilation-perfusion ratios and diffusing capacity-perfusion ratios in three types of chronic obstructive pulmonary disease]

To assess whether diffusion-limited gas exchange plays a significant role in hypoxemia in various types of chronic obstructive pulmonary disease(COPD), we analyzed the distribution of ventilation-perfusion (VA/Q) ratios and of diffusing capacity-perfusion (G/Q) ratios. We compared VA/Q and G/Q distribution in patients with three basic types of COPD: emphysematous changes, bronchiolar involvement, and airway hypersecretion, which were classified based on symptoms and on findings of high-resolution CT. The results were that 1) hypoxemia was not caused by diffusion-limited gas exchange with low G/Q regions in any type of COPD, that 2) hypoxemia was not caused by inhomogeneities in VA/Q distribution, that 3) emphysematous changes and bronchiolar involvement were associated with high and low VA/Q regions, respectively, and that 4) either hypersecretion itself or related airway abnormalities may cause low VA/Q regions to form.

[Pneumonia caused by varicella-zoster virus in a patient with rheumatoid arthritis]

A 56-year-old woman suffering from rheumatoid arthritis, was admitted to our hospital for evaluation of fever and dyspnea. A month before admission, she had been given a diagnosis of herpes zoster and was treated with an antiviral agent. However, a perineal eruption persisted. A chest X-ray film and a chest CT scan showed many diffuse nodular shadows in both lung fields. With conservative treatment, the shadows regressed along with the skin eruption and other symptoms. Pneumonia caused by varicella-zoster virus was diagnosed from the clinical course, chest roentgenographic and CT scan findings, and serological data. The risk of mortality in varicella-zoster pneumonia is high in adults, especially in immunosuppressed patients. Early diagnosis and effective treatment are, therefore, essential in the management of this disease. Though varicella-zoster pneumonia is rare, chest roentgenographic and CT scan findings are characteristic and suggestive. This case may serve as a reminder of the features of varicella-zoster pneumonia: many nodular shadows on the chest X-ray film and CT scan.

[High concentrations of interleukin-8 in bronchoalveolar lavage fluid from a patient with adult respiratory distress syndrome]

A 75-year-old man was admitted to the hospital due to acute onset of a dry cough and dyspnea on exertion. Arterial blood gas analysis showed hypoxemia (PaO2 = 63 Torr) on room air. Chest radiography and computed tomography showed diffuse bilateral infiltrates. Adult respiratory distress syndrome was diagnosed from the findings described above and from the lack of evidence of left heart failure. Diffuse alveolar damage was confirmed at autopsy. During the course of his illness, the patient underwent bronchoalveolar lavage five times. The recovered fluid had high concentrations of interleukin-8 (IL-8), with a maximum of 6260 pg/ml and a minimum of 190 pg/ml, and these values correlated with the number of polymorphonuclear cells in the fluid. Levels of leukotriene B4, another chemotactic factor for PMN, in the lavage fluid were not high. We conclude that IL-8 was a major chemoattractant for PMN in the alveoli of this patient.