Shinichi Ohdama

Determination of plasma tissue factor antigen and its clinical significance

SUMMARY. To investigate the clinical significance of determination of plasma tissue factor (TF) antigen, we have developed a highly sensitive enzyme‐linked immunosorbent assay (ELISA) for plasma TF, using two different monoclonal antibodies against TF apoprotein, 6B4 (catching antibody) and 5G9 (detecting antibody), and tetramethyl benzidine/H2O2 as substrates. Titration curves of recombinant human TF in buffer containing Triton X‐100 were linear within the range from 50 to 2000pg/ml. The total assay time was 3h. Ultracentrifugation and immunoblot analysis indicated that human plasma and urine contained 50 000g sedimentable and non‐sedimentable forms of TF, both of which were detected by our ELISA method.

Can Malignant and Benign Pulmonary Nodules Be Differentiated with Diffusion-Weighted MRI?

OBJECTIVE The objective of our study was to evaluate whether diffusion-weighted imaging (DWI) with a high b factor can be used to differentiate malignancies from benign pulmonary nodules. MATERIALS AND METHODS This study included 54 pulmonary nodules (>or= 5 mm in diameter) in 51 consecutive patients (37 men, 14 women; mean age, 65.7 years; age range, 31-88 years). Thirty-six (67%) of the 54 pulmonary nodules were malignant, and 18 (33%) were benign. Two radiologists independently reviewed the signal intensity of the nodules on DWI with a b factor of 1,000 s/mm(2) using a 5-point rank scale without knowledge of clinical data. This scale was based on the following scores: 1, nearly no signal intensity; 2, signal intensity between 1 and 3; 3, signal intensity almost equal to that of the thoracic spinal cord; 4, higher signal intensity than that of the spinal cord; and 5, much higher signal intensity than that of the spinal cord. The Mann-Whitney U test and the receiver operating characteristic (ROC) curve were used to calculate the difference between the scores of malignant and benign nodules. RESULTS On DWI, the mean score of malignant pulmonary nodules (4.03 +/- 1.16 [SD]) was significantly higher (p < 0.01) than that of benign nodules (2.50 +/- 1.47), with an area under the ROC curve of 0.796 (95% CI, 0.665-0.927). When a score of 3 was considered as a threshold, the sensitivity, specificity, and accuracy were 88.9% (95% CI, 78.6-99.2%), 61.1% (38.6-83.6%), and 79.6% (68.9-90.3%), respectively. Three small metastatic nodules (13, 16, and 20 mm) and one bronchioloalveolar carcinoma scored 1 or 2 on the 5-point rank scale. Three granulomas, two active inflammatory lung nodules, and one fibrous nodule scored 4 or 5. CONCLUSION The signal intensity of pulmonary nodules may be useful for malignant and benign differentiation on DWI. However, the interpretation of small metastatic nodules, nonsolid adenocarcinoma, some granulomas, and active inflammatory nodules should be approached with caution.

Alveolar basement membrane breaks down in diffuse alveolar damage: An immunohistochemical study

Sequential structural changes of the alveoli in diffuse alveolar damage (DAD) were examined by immunohistochemical methods. Lung specimens obtained at autopsy from 52 patients with DAD were stained with antibodies to laminin, 7S collagen (7S) and type IV collagen (type IV) for alveolar basement membrane, to von Willebrand factor, CD‐31 and thrombomodulin (TM) for the alveolar capillary endothelial cell, and to epithelial membrane antigen and surfactant apo‐protein (PE‐10) for the alveolar epithelium. Forty‐two of the patients had the exudative form of DAD; 10 of the patients had the proliferative form of DAD. The results were summarized as follows: (i) laminin was most easily impaired both in the epithelial and capillary basement membrane in the early exudative stage; (ii) following laminin, 7S and type IV in the capillary basement membrane were also injured in the early exudative stage, and recovered in the proliferative stage; (iii) subsequently, 7S and type IV in the epithelial basement membrane were also impaired in the late exudative stage, and remained impaired even in the proliferative stage; and (iv) alveolar epithelium regenerated almost completely in the late exudative stage, but staining for TM in the alveolar capillary recovered in the proliferative stage. Because the alveolar basement membrane must govern the homeostasig of alveolar tissue architecture, it was concluded that its preservation is necessary to avoid the abnormal remodeling of the alveoli in the reparative stage of DAD, if the patient survives the acute episodes of the disease.

The significance of complement activation in the pathogenesis of hypersensitivity pneumonitis: sequential changes of complement components and chemotactic activities in bronchoalveolar lavage fluids.

Hypersensitivity pneumonitis (HP) is believed to be induced by immunological mechanisms, the details of which remain to be clarified. While a role for cellular immunity is accepted in the pathogenesis of HP, several clinical observations also suggest a role for immune-complex-mediated lung injury. We have previously demonstrated the presence of chemotactic factors for polymorphonuclear cells (PMNs) in bronchoalveolar lavage (BAL) fluids of acutely ill patients with the summer type of HP found in Japan. The present study correlated chemotactic factors for PMNs with the level of C5a des Arg in BAL fluids obtained from patients with summer type HP. Furthermore, this study demonstrated that PMNs were increased in BAL fluids obtained after 2 days of avoidance of exposure to the presumptive causative agent. The percentage of PMNs in the BAL increased in proportion to the activity of the chemotactic factors. Finally, leukotriene B4 was not detected in concentrated BAL or supernatant fluids of cultured macrophages. These results suggest that complement activation in the respiratory tract may occur as the early event in the pathogenesis of HP.

Pentoxifylline prevents tumor necrosis factor-induced suppression of endothelial cell surface thrombomodulin

Thrombomodulin (TM) expression has been reported to be down-regulated by cytokines (endotoxin, interleukin-1, and tumor necrosis factor). We report, in the present study, up-regulation of surface TM antigen of human umbilical vein endothelial cells (HUVECs) by pentoxifylline (PTX) which is one of the agents that can increase intracellular cyclic AMP in HUVECs at therapeutic concentrations. Surface TM antigen was measured by an enzyme immunoassay. PTX increased surface TM antigen and intracellular cAMP in HUVECs in a dose dependent manner. Upregulation of TM by PTX was due to de novo synthesis of TM protein resulting from increased TM mRNA levels. PTX counterbalanced the TNF-induced suppression of TM expression. These results suggest that protein kinase A may be involved in cellular regulatory mechanism for TM expression and PTX may protect partially against TNF-induced endothelial cell injury and restore anticoagulant state of endothelium.

Analysis of Bronchoalveolar Lavage Cells and Fluids in Patients with Hypersensitivity Pneumonitis: Possible Role of Chemotactic Factors in the Pathogenesis of Disease

The current study concerns immunological mechanisms involved in the pathogenesis of hypersensitivity pneumonitis (HP) by an analysis of the cells and chemotactic factors (CF) obtained by bronchoalveolar lavage (BAL). Nine patients at an acute stage (HP acute, 8 summer type and 1 pigeon breeders lung) and 4 patients at a quiescent stage (HP quiescent, 3 summer type and 1 pigeon breeders lung) were included. The results indicate that: CF for polymorphonuclear cells (PMN) in HP acute were significantly more potent than in HP quiescent; CF for mononuclear cells were not significantly different in the groups; the percentage of lymphocytes in HP acute was significantly greater even though HP quiescent revealed greater percentages of lymphocytes as compared to normal controls; determination of T cell subsets employing OKT antibodies revealed the ratio of OKT8+ cells to OKT4+ cells in HP acute was significantly higher than in HP quiescent, and chemotaxis for PMN was marginally correlated with the percentage of OKT8+ cells at the acute stage of disease.

Sliding thin slab, minimum intensity projection imaging for objective analysis of emphysema.

PurposeThe aim of this study was to determine whether sliding thin slab, minimum intensity projection (STS-MinIP) imaging is more advantageous than thin-section computed tomography (CT) for detecting and assessing emphysema.Materials and methodsObjective quantification of emphysema by STS-MinIP and thin-section CT was defined as the percentage of area lower than the threshold in the lung section at the level of the aortic arch, tracheal carina, and 5 cm below the carina. Quantitative analysis in 100 subjects was performed and compared with pulmonary function test results.ResultsThe ratio of the low attenuation area in the lung measured by STS-MinIP was significantly higher than that found by thin-section CT (P < 0.01). The difference between STS-MinIP and thin-section CT was statistically evident even for mild emphysema and increased depending on whether the low attenuation in the lung increased. Moreover, STS-MinIP showed a stronger regression relation with pulmonary function results than did thin-section CT (P < 0.01).ConclusionSTS-MinIP can be recommended as a new morphometric method for detecting and assessing the severity of emphysema.

Pulmonary emphysema: histopathologic correlation with minimum intensity projection imaging, high-resolution computed tomography, and pulmonary function test results.

Objective: To prospectively evaluate the use of minimum-intensity projection (minIP) imaging, high-resolution (HR) computed tomography (CT), and pulmonary function tests for quantifying emphysema with histopathologic examination. Methods: MinIP and HRCT imaging data (n = 23) were obtained, and relative areas of the lung with attenuation values below thresholds from −940 to −1000 Hounsfield units (HU) and first to 13th percentiles were calculated for both data. Pulmonary function tests were performed before lung resection. These parameters were compared with mean alveolar perimeters measured on resected samples. Results: Strongest correlations with mean alveolar perimeter were obtained at −990 HU and the fifth percentile by minIP, −1000 HU and the seventh percentile by HRCT, and diffusion capacity. The correlation between the mean alveolar perimeter and relative areas below −990 HU by minIP showed significantly higher extension (0%-51%) than those below −1000 HU by HRCT (1%-21%). Conclusions: MinIP imaging is more than 2½ times more predictive for quantifying emphysema than HRCT, although diffusion capacity of lung for carbon monoxide is also a valid index.

Sliding thin slab, minimum intensity projection of the lung in asymptomatic subjects: lower limits of lung attenuation, without airways.

PurposeA sliding thin slab, minimum intensity projection (STS-MinIP) is considered to be useful for detecting diseases that decrease lung attenuation. For evaluating these diseases, it would be useful to ascertain the lower limits of normal lung attenuation, allowing a division between normal and subnormal attenuation. However, normal lung attenuation may vary depending on respiratory status, anatomical position, and patient background factors. Our aim was to determine whether the lower limits of lung attenuation, without airways, in asymptomatic subjects using STS-MinIP varies under different conditions.Materials and methodsThe study subjects were 43 volunteers without pulmonary symptoms. STS-MinIP was performed at full inspiration and full expiration at three levels of the lung. The lower limits of lung attenuation were compared among the three lung levels and between full inspiration and full expiration, the sexes, age groups, smokers and nonsmokers, and the right and left lungs.ResultsThe lower limits of lung attenuation had significantly different Hounsfield unit values among lung levels, between the sexes at full inspiration, and between age groups at full expiration.ConclusionThis study shows that the lower limits of lung attenuation are influenced by lung fields, sex, and, on expiration, age.

Chemotactic Factors Present in the Supernatants of Cultured Sarcoid Granulomas

The present study was undertaken to test whether cultured lymphocytes and epithelioid cells from sarcoid granulomas obtained from patients with active stage 2 sarcoidosis produced chemotactic factors (CF) for leukocytes as assessed by modified Boydens method. The results indicate that: (1) CF for mononuclear cells and for neutrophils were detected in supernatants from cultured sarcoid granulomas; (2) similar activity was detected in culture supernatants from both lymphocytes and epithelioid cells; (3) CF present in the supernatants of cultured epithelioid cells were similar physically to those which other investigators have disclosed to be released by alveolar macrophages, (4) CF in the supernatants of cultured lymphocytes were similar to the lymphokines based on an estimation of molecular size; (5) neutrophils from patients with sarcoidosis were less responsive to zymosan-activated sera and did not respond well to CF derived from their own granuloma, whereas mononuclear cells from sarcoid patients responded well to CF. In conclusion, CF are present in the supernatants of cultured sarcoid granulomas and they appear to preferentially attract mononuclear cells from sarcoid patients.