Correlation between pleural tags on CT and visceral pleural invasion of peripheral lung cancer that does not appear touching the pleural surface.

OBJECTIVES: To evaluate the association between a sign and visceral pleural invasion (VPI) of peripheral non-small-cell lung cancer (NSCLC) that does not appear touching the pleural surface. METHODS: A total of 221 consecutive patients with NSCLC that did not appear touching the pleural surface, ≤ 3 cm in solid tumor diameter, and was surgically resected between January 2009 and December 2015 were included. We focused on the flat distortion of the tumor caused by an arch-shaped linear tag between the tumor and the pleura on CT and named it a bridge tag sign. We evaluated the associations between the clinicopathological features of the tumor, including the bridge tag sign, and VPI. We also evaluated the associations between histopathological findings and the bridge tag sign. The utility of the bridge tag sign in the diagnosis of VPI was statistically assessed. RESULTS: The bridge tag sign was observed in 48 (20.8%) patients. VPI was positive in 9 (4.1%) patients; among these, the bridge tag sign was positive in 8 patients. In multivariate analysis, a bridge tag sign was significantly associated with VPI. The bridge tag sign was associated with longer contact length of the pleura with the tumor and trapezoid type pleural retraction. The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the bridge tag sign in the diagnosis of VPI were 88.9%, 83.5%, 83.7%, 18.6%, and 99.4%, respectively. CONCLUSIONS: A bridge tag sign on CT might improve the accuracy of the prediction of VPI. KEY POINTS: • We present the bridge tag sign which is defined as a flat distortion of an NSCLC tumor by an arch-shaped linear tag between the tumor and chest wall or interlobar fissure. • The bridge tag sign was an independent predictive factor for visceral pleural invasion. • The sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of the bridge tag sign in the diagnosis of visceral pleural invasion were 88.9%, 83.5%, 83.7%, 18.6%, and 99.4%, respectively.

PD-L1 expression on neoplastic or stromal cells is respectively a poor or good prognostic factor for adult T-cell leukemia/lymphoma.

Programmed cell death ligand 1 (PD-L1) is expressed on both tumor and tumor-infiltrating nonmalignant cells in lymphoid malignancies. The programmed cell death 1 (PD-1)/PD-L1 pathway suppresses host antitumor responses, although little is known about the significance of PD-1/PD-L1 expression in the tumor microenvironment. To investigate the clinicopathological impact of PD-L1 expression in adult T-cell leukemia/lymphoma (ATLL), we performed PD-L1 immunostaining in 135 ATLL biopsy samples. We observed 2 main groups: 1 had clear PD-L1 expression in lymphoma cells (nPD-L1(+), 7.4% of patients), and the other showed minimal expression in lymphoma cells (nPD-L1(-), 92.6%). Within the nPD-L1(-) group, 2 subsets emerged: the first displayed abundant PD-L1 expression in nonmalignant stromal cells of the tumor microenvironment (miPD-L1(+), 58.5%) and the second group did not express PD-L1 in any cell (PD-L1(-), 34.1%). nPD-L1(+) ATLL (median survival time [MST] 7.5 months, 95% CI [0.4-22.3]) had inferior overall survival (OS) compared with nPD-L1(-) ATLL (MST 14.5 months, 95% CI [10.1-20.0]) (P = .0085). Among nPD-L1(-) ATLL, miPD-L1(+) ATLL (MST 18.6 months, 95% CI [11.0-38.5]) showed superior OS compared with PD-L1(-) ATLL (MST 10.2 months, 95% CI [8.0-14.7]) (P = .0029). The expression of nPD-L1 and miPD-L1 maintained prognostic value for OS in multivariate analysis (P = .0322 and P = .0014, respectively). This is the first report describing the clinicopathological features and outcomes of PD-L1 expression in ATLL. More detailed studies will disclose clinical and biological significance of PD-L1 expression in ATLL.

Expression of programmed death ligand 1 is associated with poor prognosis in myeloid sarcoma patients.

Myeloid sarcoma (MS) is a rare condition and is an extramedullary tumour of immature myeloid cells. It is now known that the programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) pathway suppresses the host antitumor responses and that these products are expressed on both tumour cells and tumour-infiltrating cells in various malignancies. However, little is known about the significance of PD-1/PD-L1 expression on tumour cells and tumour microenvironmental cells in MS. To investigate the clinicopathological significance of PD-1/PD-L1 expression in MS, we analyzed 98 patients by immunohistochemistry. Of these, 10.2% of cases had neoplastic tumour cells positive for PD-L1 (nPD-L1+ ). However, the rate of nPD-L1+ was <5% (range: 0.27 to 2.97%). On the other hand, PD-L1 expression on 1 or more of stromal cells in the tumour microenvironment (miPD-L1+ ) was observed in 37.8% of cases. Because all nPD-L1+ cases expressed PD-1 on less than 5% of tumour cells, we compared the miPD-L1+ and miPD-L1- groups. There was a correlation between miPD-L1+ status and the number of PD-1-expressing tumour -infiltrating lymphocytes (PD-1+ TILs; P = .0229). miPD-L1+ was found to be associated with poorer overall survival and progression-free survival (P = .00392, P = .00261, respectively). Multivariate analysis also confirmed miPD-L1+ to be an independent poor prognostic factor. In conclusion, our study indicated that the immunotherapy blocking the PD-1/PD-L1 pathway may improve the clinical outcome of MS.

[Assessment of Fat-free Diet for Postoperative Chylothorax].

BACKGROUND: Chylothorax after lung cancer surgery is relatively rare but must be considered as a complication of thoracic surgery. METHOD: Between January 2012 and June 2017, 818 patients underwent lung cancer surgery at our hospital. Among them, 14 (1.7%) patients with chylothorax were retrospectively reviewed. Three patients were treated with oral intake cessation except water and total parental nutrition( TPN)[TPN group], 11 patients were treated with a fat-free diet( fat-free diet group). RESULTS: The drainage period was similar in both group [group TPN;13 (12~14) days and group fat-free diet;15.7 (6~42) days]. In the TPN group, 3 patients underwent pleurodesis and no patient needed surgical intervention. In the fat-free diet group, 5 patients improved only with diet management. Pleurodesis was necessary in 5 of which 3 underwent surgical intervention. CONCLUSIONS: A fat-free diet is useful in treating chylothorax after lung cancer surgery.

Papillary thyroid carcinoma expressing CD20.

We identified a case of lymphadenopathy of metastatic papillary thyroid carcinoma (PTC) with CD20 expression, which was also expressed by the primary tumor. CD20 expression was identified using immunohistochemistry (IHC) in metastatic PTC biopsy samples from a 58-year-old woman. CD20 expression was initially determined using a CD20-recognizing L26 clone. To validate this phenomenon, we performed IHC with another antibody that recognizes the N-terminus of CD20 and fluorescent double staining using anti-TTF-1 and anti-CD20 antibodies. Taken together, we concluded metastatic PTC expressed CD20. We also examined 21 additional PTC cases and found four more cases that were CD20 positive. Therefore, five of the 22 (23%) cases were positive for CD20. In the positive cases, four cases were classical papillary thyroid carcinoma and one case was a follicular variant of papillary thyroid carcinoma. CD20 is an important target for molecularly targeted therapy for a subset of B-cell lymphomas. Complement-dependent and antibody-dependent cellular cytotoxicities are important effector mechanisms of anti-CD20 therapy. Here, for the first time, we report PTC with expression of CD20. Our findings provide a rationale for treating CD20-positive PTC patients with anti-CD20 therapy.

Survival after initial lung metastasectomy for metastatic colorectal cancer in the modern chemotherapeutic era.

BACKGROUND: A clear survival benefit has been reported for lung metastasectomy for colorectal cancer, and several clinicopathological prognostic factors have been proposed in the past. However, clinical advances, such as chemotherapy and radiographic imaging, should have improved patient outcome and may have altered prognosticators. This study aimed to assess patient survival and determine prognostic factors for survival and recurrence in patients who underwent initial lung metastasectomy for colorectal cancer in the modern clinical era. METHODS: Clinicopathological data and outcomes of 59 patients who underwent curative initial lung metastasectomy for colorectal cancer from 2004 to 2012 at a single institution in Japan were retrospectively investigated. Survival was estimated using the Kaplan - Meier method, and Cox proportional hazards regression models were used to estimate the prognostic impacts of each variable in univariate and multivariate analysis. RESULTS: The 5-years overall and disease-free survival rates were 54.3 and 40.6%, respectively. A disease-free interval < 24 months after colorectal cancer resection (P = 0.004) and a serum carcinoembryonic antigen ≥ 5.0 ng/mL before initial lung metastasectomy (P = 0.015) were independent predictors for poor overall survival. Moreover, the disease-free interval after colorectal cancer resection < 24 months (P = 0.010) and a colorectal cancer with N2 stage disease (P = 0.018) were independently associated with poor disease-free survival. On the other hand, the number of lung metastasis was not identified as a poor prognostic factor for both overall and disease-free survival. CONCLUSIONS: Our findings demonstrated similar or slightly better overall survival, and substantially favorable disease-free survival as compared with past reports. Poor prognostic factors for overall survival appeared not to differ from those of past studies, although this modern series did not determine the number of lung metastasis as a poor prognostic factor, which should be investigated in future studies. Moreover, initial lung metastasectomy is not expected to be a curable treatment for patients with both a short disease-free survival after colorectal cancer resection and colorectal cancers with N2 stage disease.

Mucinous cystic tumor with CK20 and CDX2 expression of the thymus: Is this a benign counterpart of adenocarcinoma of the thymus, enteric type?

Primary thymic adenocarcinoma is extremely rare. Moreover, thymic pure epithelial benign neoplasms are extremely rare. We encountered a cystic tumor almost purely composed of goblet cell-like mucus-producing cells of the thymus. A mass lesion of the mediastinum was detected in a 54-year-old man. The gross specimen presented a unilocular cystic lesion containing abundant mucin, measuring 8 × 5.5 × 4.5 cm. Microscopic examination revealed a cystic tumor consisting of bland mucus-producing cells resembling goblet cells and forming tiny daughter cysts within the dense fibrous capsule. No destructive growth or infiltration into surrounding thymic tissue was observed. Papillary growth was found in a small focus. Immunohistochemically, tumor cells were positive for cytokeratin 20 and caudal type homobox 2, which are representative markers of enteric differentiation. The patient has been well without any recurrence for approximately ten years after the operation. Thus, the tumor should be regarded as a mucinous cystic tumor in the thymus. Very recently, thymic adenocarcinoma with enteric differentiation was proposed as a novel subtype of thymic carcinoma. This case could be regarded as a benign counterpart of adenocarcinoma of the thymus, enteric type. A further follow-up study is required to confirm the exact biological behavior of this tumor.

Cone-Beam Computed Tomography-Guided Marking of Small Pulmonary Nodules with Surgical Clips.

BACKGROUND: Preoperative computed tomography-guided marking can help identify small non-palpable pulmonary nodules during surgery. However, this technique is associated with the risk of air embolism. We retrospectively evaluated whether small pulmonary nodules could be intraoperatively localized using cone-beam computed tomography (CBCT). METHODS: A hybrid operating room permitting stable lateral positioning and scanning from the pulmonary apex to the base was used in all patients. CBCT images were obtained using a 10-s protocol with 180º rotation of the C-arm flat panel detector around the patient. Clips were placed on the visceral pleura to help guide pulmonary nodule localization. Partial pulmonary resection was performed using video-assisted thoracoscopic surgery at the predicted nodule site. RESULTS: Between July 2013 and June 2019, 132 patients with 145 lesions underwent this procedure at our center. The detection rate of lesions on CBCT was 100%. The pathological diagnoses were primary lung cancer, metastatic pulmonary tumors, and benign lesions. The average consolidation-to-tumor ratio was 0.65 for all nodules, with ratios of 0.33, 0.96, and 0.70 for primary lung cancer, metastatic pulmonary tumors, and benign lesions, respectively. No complications related to this localization method were observed. CONCLUSIONS: CBCT-guided intraoperative localization is safe and feasible for non-palpable small pulmonary nodules. This technique may eliminate the risk of serious complications such as air embolism.

Aortic valve replacement in patients with an anomalous left circumflex artery: technical considerations.

The abnormal origin of the left circumflex artery from the proximal right coronary artery (RCA) is considered a coronary artery anomaly. Most of the coronary artery anomalies are diagnosed incidentally by coronary artery angiography, and several considerations are needed to avoid fatal complications in patients undergoing aortic valve replacement (AVR). We report a case of AVR with anomalous origin of the left circumflex artery from a common ostium of the RCA, and discuss the use of a smaller prosthesis to avoid compression of the anomalous left circumflex artery.

Comparison of PD-L1 immunohistochemical assays and the significance of PD-L1 expression in thymoma.

Thymoma is a relatively rare malignancy, which is categorized as thymic epithelial tumor but known as the most common pathology that is developed in the anterior mediastinum. Complete resection is recommended for localized tumors and usually favorable prognosis can be obtained. However, poor survival period has been reported in unresectable cases exhibiting extensive invasion or distant metastasis, as effective chemotherapeutic regimens are restrained. We previously assessed expression of programmed death ligand 1 (PD-L1) and programmed death 1 (PD-1) and discussed their prospective application in the immunotherapy of thymic epithelial tumors. After our publication, additional studies using reliable PD-L1 antibodies, which are currently administered to predict efficacy of PD-1/PD-L1 blockade therapy were performed and further characterized PD-L1 in thymoma. Herein, recent knowledge in relation to the significance of PD-L1 expression in thymoma is reviewed based on recent findings using qualified PD-L1 clones. Most studies coherently found high expression of PD-L1 on the cell membrane and cytoplasm of tumor epithelial cells in accordance with previous reports, which is a predictive marker for effectiveness of anti-PD-1/PD-L1 drugs, even when approved PD-L1 antibodies were employed. On the other hand, PD-L1 expression on tumor infiltrating immune cells remains to be sufficiently determined. High PD-L1 expression can be expected in cases with high grade histological subtypes, such as type B2/B3 thymomas, or those with advanced stages III or IV of the disease. Interestingly, the level of PD-L1 expression was found to be upregulated after chemotherapy compared with that before, which could be explained by immunogenic cell death. The prognostic impact of PD-L1 expression in thymoma might be found only when thymic carcinoma patients were excluded. Furthermore, it also could be identified when we analyzed thymomas completely resected, distinct from biopsy and incompletely resected cases.

Mesenteric Myxofibrosarcoma: A Case Report.

Myxofibrosarcoma is a soft tissue sarcoma that occurs in elderly patients. Primary myxofibrosarcoma rarely arises in the mesentery; this is the fourth known case of myxofibrosarcoma presenting as a mesenteric tumor. A 62-year-old male with a mesenteric myxofibrosarcoma presented with an abdominal mass; his symptoms were frequent urination and a sense of abdominal pressure. He was admitted for further examination. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed a mesenteric lesion. The preoperative diagnosis was a suspected malignant myxoid tumor. We performed a curative resection with wide margins. The histopathological and immunohistochemical findings confirmed that the tumor was mesenteric myxofibrosarcoma. The postoperative course was uneventful, and there have been no signs of relapse for three years to date after surgery. It is difficult to make a definitive diagnosis of mesenteric myxofibrosarcoma using only CT or MRI. However, when the preoperative findings suggest a malignant mesenteric tumor, then the best practice is resection with sufficient margins.

Influence of intersegmental plane size and segment division methods on preserved lung volume and function after pulmonary segmentectomy.

OBJECTIVES: We previously reported that the use of a stapler to divide intersegmental planes did not decrease preserved pulmonary volume or function relative to electrocautery. However, preservation of pulmonary volume or function can be compromised when a stapler is used with larger intersegmental planes. Here, we assessed the correlations between preserved lung volume and pulmonary function after segmentectomy and the size of the intersegmental planes, based on the division method. METHODS: Intersegmental plane sizes in 56 patients were semi-automatically calculated using image analysis software on computed tomography images. The ratios of the remnant segment and ipsilateral lung volumes to their preoperative values (R-seg and R-ips) and the ratio of the postoperative pulmonary function relative to the predicted value were calculated based on three-dimensional volumetry. Correlations between preserved lung volume and pulmonary function and the intersegmental plane sizes were analyzed according to the division method. RESULTS: Intersegmental planes were divided by either electrocautery or with a stapler (EC/Mixed) in 21 patients and by stapler alone (ST) in 35 patients. There was no difference in the average size of the intersegmental planes between the two groups. The intersegmental plane size negatively correlated with R-seg in the ST group. CONCLUSIONS: Using the stapler method, as the size of the intersegmental planes increased, the preserved remnant segmental volume decreased; however, relation between the plane size and preserved pulmonary function was unclear. These findings indicate that stapler use is acceptable even for large intersegmental planes.

Temporary airway stenting for giant anterior mediastinal tumor biopsy: Two case reports.

INTRODUCTION: When the management of an anterior mediastinal tumor requires general anesthesia, airway narrowing and obstruction may occur secondary to muscle relaxation. PRESENTATION OF CASES: Two men (ages, 15 and 36 years) presented with a giant anterior mediastinal tumor and central airway obstruction. We used Dumon stents to effectively secure the airway in both patients. After chemotherapy, stent removal was safely performed in each case because the tumor was substantially smaller. DISCUSSION: Dumon stents effectively secured the airway. These stents were easily removed after chemotherapy without severe complications. CONCLUSION: Temporary stenting is useful in patients with a giant anterior mediastinal tumor who require general anesthesia.

Thymic tumors and immune checkpoint inhibitors.

Thymoma and thymic carcinoma, known as the most common features of thymic epithelial tumors (TETs), are thoracic malignancies displaying varied clinical features and prognosis. These neoplasms being frequently ineligible for surgical complete resection as a curative treatment because of extensive tumor spread, effectual nonsurgical treatments are needed; however, an optimal chemotherapeutic regimen has not been identified, although some regimens have been shown to be active. Immunotherapy is effective for other malignancies and may be promising as a therapeutic alternative for refractory TETs. Thus far, several studies have determined the expression of programmed death ligand 1 (PD-L1) and programmed death 1 (PD-1) in TETs, including its clinicopathological and prognostic significance. The results have been conflicting due to the different immunohistochemical antibodies employed and distinct cutoff values. However, many authors identified abundant PD-L1 expression in TETs, which is considered as an important predictive factor for therapeutic effect of PD-1 inhibitors in other malignant tumors. In some clinical trials, an acceptable clinical efficacy of PD-1 inhibitor for TETs has been reported as expected; however, concerns regarding immunological adverse events have been raised. To optimize these therapeutic agents for refractory TETs, additional studies which evaluate clinical availabilities of immunotherapeutic drugs and characterize their basic mechanisms of action against immunotherapeutic targets are both urgently required.

Surgical resection of extramedullary haematopoiesis in the posterior mediastinum.

Extramedullary haematopoiesis is a rare disease that is usually associated with haematologic disorders such as thalassemia, myelodysplastic syndrome, and hereditary spherocytosis. It frequently occurs in the liver, spleen, and lymph nodes. Rarely, it occurs in the posterior mediastinum. We report the case of a 59-year-old man with lateral posterior mediastinal masses that were incidentally detected during treatment for hereditary spherocytosis. We performed video-assisted thoracic surgery to confirm the diagnosis and differentiate the masses from neurogenic tumours and other posterior mediastinal diseases. The pathological findings were consistent with intrathoracic extramedullary haematopoiesis. Although extramedullary haematopoiesis can be managed without interventions, surgery may be required in some cases. In such cases, video-assisted thoracoscopic surgery is advised because it is a useful and less invasive procedure.

Lung function in the late postoperative phase and influencing factors in patients undergoing pulmonary lobectomy.

BACKGROUND: Lung function in the late postoperative phase after pulmonary lobectomy is insufficiently characterized. This study aimed to appraise lung function in the late postoperative phase according to vital capacity (VC) and forced expiratory volume in 1 second (FEV1) in patients who underwent pulmonary lobectomy. METHODS: Pre- and postoperative VC and FEV1 were reviewed in 112 patients who underwent pulmonary lobectomy. Postoperative lung volume was assessed >1 year after surgery. Postoperative decreases in VC and FEV1 were compared with preoperative predicted values among patients who underwent resection of specific lobe. Determinants effecting a decrease in lung function were also investigated. RESULTS: A mean postoperative decreased VC of 10.5%±1.8% was recorded in patients who underwent right upper lobectomy (RU), 7.2%±1.5% for right middle lobectomy (RM), 14.3%±2.3% for right lower lobectomy (RL), 16.6%±3.0% for left upper lobectomy (LU), and 14.7%±2.5% for left lower lobectomy (LL). Corresponding FEV1 values were 14.8%±1.8% for RU, 11.9%±4.0% for RM, 14.9%±2.3% for RL, 17.9%±2.9% for LU, and 15.1%±2.4% for LL. The actual decreasing rate of VC was overestimated in patients who underwent RU, RL, LU, and LL. In contrast, FEV1 was overestimated only in patients who underwent RL and LL. Patients with chronic obstructive pulmonary disease (COPD) exhibited significantly better preservation of FEV1. CONCLUSIONS: Patients scheduled for RL and LL, or those with COPD, appeared to exhibit preserved lung function in the late postoperative phase after pulmonary lobectomy.

Periostin Expression in Non-Small Cell Lung Cancer: Clinical Significance.

Periostin is an extracellular matrix N-glycoprotein that is a major constituent of the desmoplastic stroma around solid tumors. Periostin promotes tumor invasion and metastasis via epithelial-mesenchymal transition. The aims of this study were to evaluate periostin expression immunohistochemically and quantitatively in patients with non-small cell lung cancer (NSCLC) and to assess any associations with clinical features and prognosis. A total of 184 specimens of NSCLC tissue were investigated, including 134 adenocarcinomas, 39 squamous cell carcinomas, and 11 other histologic subtypes. The intra-tumoral periostin expression area in each captured field was calculated using the image processing integration software WinROOF. The mean periostin expression score was classified as high or low by the median value of its expression area. Univariate analysis demonstrated that gender, tumor size, T status, N status, stage, histologic type, smoking habits, percent vital capacity, 1% forced expiratory volume, and pleural invasion were each significantly associated with periostin scores. Multivariate analysis revealed that high periostin expression score was an independent prognostic factor significantly associated with decreased cancer-specific survival (HR, 3.65; 95% CI, 1.04-12.84; P=0.0439). We concluded that intratumoral periostin expression was an independent prognostic factor for NSCLC.

Tumor Spread Through Air Spaces Identifies a Distinct Subgroup With Poor Prognosis in Surgically Resected Lung Pleomorphic Carcinoma.

BACKGROUND: Tumor spread through air spaces (STAS) has recently been reported as a novel form of lung adenocarcinoma invasion that can negatively affect survival; however, its role in pleomorphic carcinoma remains unclear. The goal of this study was to characterize tumor STAS in pleomorphic carcinoma, including its association with clinicopathologic features and prognosis. METHODS: Tumor specimens obtained from 35 consecutive patients with pleomorphic carcinoma who underwent surgical resection between 2009 and 2015 were reviewed. Tumor STAS was defined as tumor cells spreading within the air spaces in the surrounding lung parenchyma beyond the edge of the primary tumor. RESULTS: Fourteen patients (40%) had evidence of STAS-positive pleomorphic carcinomas. Three types of morphologic findings were observed: single cells, small tumor cell clusters, and tumor nests. Tumor necrosis tended to be more prevalent in STAS-positive tumors than in STAS-negative tumors (P = .094). Patients with STAS experienced significantly worse recurrence-free survival (P = .005) and overall survival (P = .002) rates than those without STAS. Moreover, multivariate analysis revealed that tumor STAS was an independent risk factor for both recurrence (P = .014) and poor overall survival (P = .042). CONCLUSIONS: In this first study of its kind, tumor STAS in patients with pleomorphic carcinoma was shown to be associated with high recurrence rates and poor survival after surgical resection. Hence, tumor STAS can serve as a predictor of postoperative survival; this information will enable better risk stratification and more effective clinical management of patients with this rare type of tumor.

Prediction computer program for whole body temperatures and its application under various working level and thermal environmental condition combinations.

We introduced a computer program developed for the numerical analysis of thermal conditions of all segments and blood circulatory systems in the human body to precisely evaluate human thermal physiological responses. In this program, a cylindrical model consisting of internal multi-layers is adapted for the segment of the human body. For the multi-layered concentric cylindrical model we adopted a new numerical solution method. By using this computer program the internal tissue temperatures, heat fluxes and blood temperatures of all segments in the human body could be calculated simultaneously. This program also included a subroutine for calculation of thermoregulatory response. This paper describes the improvements made to this computer program for simulating individual physical differences and its application to various working levels. The main points for improvement were the assigning procedures of physical characteristics of individuals and local muscle heat production. The improved computer program was used to simulate the whole body temperatures of the subjects during exercise described in Gagge, Stolwijk and Saltin (1969) were simulated. The calculated results were agreed with the measured results under the combination of the three kinds of exercise and the three types of environmental condition.

The study of activity median aerodynamic diameter using imaging plate technique for assessment of effective dose from radon and its decay products.

The indoor workplace environment was evaluated for exposure to radon and its decay products at two Universities in two metropolises of Japan. The mean radon concentrations in Nagoya University (NU) and Hokkaido University (HU) were 16.7 Bq m(-3) and 18.0 Bq m(-3), respectively. Activity median aerodynamic diameter (AMAD) of particles at NU ranged from 172 nm approximately 205 nm and at HU from 186 nm approximately 300 nm. Estimated effective doses for five usual sites of NU by ICRP approach was 0.15 mSvy(-1) approximately 0.76 mSvy(-1) and by UNSCEAR approach was 0.05 mSvy(-1) approximately 0.24 mSvy(-1). The effective dose for the same of HU by ICRP 66 approach was 0.16 mSvy(-1) approximately 0.79 mSvy(-1) and by UNSCEAR 2000 approach was 0.05 mSv y(-1) to 0.26 mSv y(-1). The two approaches differs on an average by a factor 2.3- approximately 4.7. The AMAD of obtained particle size distribution at NU has an average total deposition of 23% in human respiratory tract and 20% at HU.