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Treatment of recurrent malignant pleural mesothelioma (MPM) remains challenging. Our study examined the efficacy, tolerability, and safety of nivolumab with ipilimumab treatment for recurrent MPM after primary curative-intent surgery.Treatment comprised 360 mg nivolumab every 3 weeks and 1 mg/kg of ipilimumab every 6 weeks, both administered intravenously. Both were discontinued for progressive disease or serious adverse events (AEs). Additional post-treatment data were evaluated, including objective response rate (ORR), disease control rate (DCR), post-treatment survival, progression-free survival (PFS), and AEs. Tumor response was assessed using the modified Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Survival analysis was estimated using a Kaplan-Meier plot. Feasibility analysis was performed using the National Cancer Institute Common Terminology Criteria for AEs version 5.0.Forty-one patients received nivolumab with ipilimumab for recurrent MPM after primary curative-intent surgery (median follow-up, 10.4 months; median treatment, 5.1 months). Overall, 18 patients exhibited partial response, 13 exhibited stable disease, and 10 had documented progressive disease. ORR and DCR were 43.9 and 75.6%, respectively. The 12-month post-treatment survival rate and PFS rate were 74.2 and 40.0%, respectively (median survival, not calculated; median PFS, 7.3 months). Further, 47 AEs were reported in 29 patients (70.7%), including grade 3-4 AEs in 14 patients (34.1%). Grade 4 hepatobiliary disorders were observed in 2 patients and grade 4 neutropenia was observed in 1.Nivolumab with ipilimumab treatment in patients with recurrent MPM after primary surgical treatment may be clinically efficacious, although serious AEs may be frequently observed.

IntroductionA curative-intent surgical procedure, pleurectomy/decortication, for malignant pleural mesothelioma is accompanied by a high incidence of major postoperative complications. Although epidural block, which suppresses nociception during and after surgery, reportedly has both benefits and disadvantages in terms of outcomes after thoracic surgery for other diseases, the effects of epidural block on major complications after pleurectomy/decortication have not been evaluated. The aim of this study was to evaluate the association between epidural block and major postoperative complications following pleurectomy/decortication.MethodsIn a single-institutional observational study, consecutive adult patients undergoing pleurectomy/decortication under general anesthesia were enrolled from March 2019 to December 2021. Multivariable logistic regression analysis was performed to determine the association between perioperative variables and major complications. Next, patients were divided into two groups: general anesthesia with and without epidural block. Incidences of major postoperative complications, defined as Clavien-Dindo grades≥III, were compared between groups.ResultsIn all patients enrolled with American Society of Anesthesiologists (ASA) physical status II or III (n=99), general anesthesia without epidural block was identified as a sole risk factor for major complications among perioperative variables. The incidence of major complications was 32.3% (95% CI 19.1% to 49.2%) in patients with epidural block (n=34), which was significantly lower than 63.1% (95% CI 50.9% to 73.8%) in patients without epidural block (n=65). In sensitivity analysis in patients with ASA physical status II alone, the same results were obtained.ConclusionEpidural block is likely associated with reduction of the incidence of major complications after pleurectomy/decortication for malignant pleural mesothelioma under general anesthesia.

We previously established a novel method of lung repair called the ventilation and anchoring (V/A) method. We evaluated the usefulness of the V/A method for controlling air leakage during pleurectomy/decortication (P/D).For this study, we enrolled patients with malignant pleural mesothelioma (MPM) who planned to receive P/D. Our lung repair method involves (1) suturing lung parenchyma for an apparent injured lesion and (2) coating the lung parenchyma with fibrin glue (FG) using the V/A method. The tidal volume (TV) was measured under pressure-controlled ventilation in the ipsilateral-affected lung 10 times at the following four points: after thoracotomy, at completion of visceral pleurectomy, after suturing lung parenchyma, and 5 min after coating with FG. The primary endpoint was the mean TV (mTV) change, and the secondary endpoints were the duration of air leakage and incidence of pleurodesis.Between April 2014 and April 2016, 25 patients of the 29 consecutive patients enrolled were eligible. The mTV significantly decreased after completion of visceral pleurectomy but significantly increased after repair of the lung parenchyma, especially after coating with FG. The median duration of postoperative air leakage was 4 days (range: 2-19 days). Postoperative air leakage 7 days was observed in 11 (44%) patients. Of these 11 patients, 6 received pleurodesis; however, no further revision was needed.Significant increases in TV were observed after coating with FG via the V/A method during P/D. Coating with FG using the V/A method can contribute to a reduction in air leakage during P/D.

BACKGROUND: The ability of circulating tumor cells (CTCs) to identify lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) could improve pathological diagnosis and the selection of treatments for non-small cell lung cancer (NSCLC). Previous studies have shown that deoxyribonucleic acid (DNA) methylation exhibits cell and tissue specificity. Thus, we aimed to explore the methylation status of CTCs in LUAD and LUSC and identify the potential biomarkers. METHODS: We first analyzed Infinium 450K methylation profiles obtained from The Cancer Genome Atlas and Gene Expression Omnibus. We then performed whole-genome sequencing of CTCs in tumor and matched normal lung tissues and white blood cells from 6 NSCLC patients. RESULTS: The bioinformatics analysis revealed a NSCLC-specific DNA methylation marker panel, which could accurately distinguish between LUAD and LUSC with high diagnostic accuracy. The whole-genome sequencing of CTCs in NSCLC patients also showed 100% accuracy for distinguishing between LUAD and LUSC based on the CTC methylation profiles. To investigate the function of CTCs, we further analyzed similar and different methylation profiles between the CTCs and their primary tumors, and found very high similarities between the CTCs and their primary tumor tissues, indicating that these cells inherit information from primary tumors. However, the CTCs also displayed some characteristics that differed to those of primary tumor tissues, which suggest that CTCs acquire some unique characteristics after migrating from the primary tumor; these characteristics may partly explain the ability of tumor cells to evade immune surveillance. CONCLUSIONS: Our findings provide insights into the potential use of CTCs in the pathological classification of NSCLC patients. Our findings also show how CTC primary tumor inheritance and CTC evolution affect metastasis and immune escape.

Phosphodiesterase 5 inhibition (PDE5i) activates cGMP-dependent protein kinase (PKG) and ameliorates heart failure; however, its impact on cardiac mitochondrial regulation has not been fully determined. Here, we investigated the role of the mitochondrial regulator peroxisome proliferator-activated receptor γ co-activator-1α (PGC1α) in the PDE5i-conferred cardioprotection, utilizing PGC1α null mice. In PGC1α(+/+) hearts exposed to 7 weeks of pressure overload by transverse aortic constriction, chronic treatment with the PDE5 inhibitor sildenafil improved cardiac function and remodeling, with improved mitochondrial respiration and upregulation of PGC1α mRNA in the myocardium. By contrast, PDE5i-elicited benefits were abrogated in PGC1α(−/−) hearts. In cultured cardiomyocytes, PKG overexpression induced PGC1α, while inhibition of the transcription factor CREB abrogated the PGC1α induction. Together, these results suggest that the PKG–PGC1α axis plays a pivotal role in the therapeutic efficacy of PDE5i in heart failure.

Background/aim To evaluate the incidence and grade of radiation pneumonitis after volumetric modulated arc therapy (VMAT) performed for the treatment of non-small cell cancer (NSCLC). Patients and methods Fifty consecutive non-surgical candidates with NSCLC underwent VMAT. Thirty-five patients had stage-III tumors and 15 had recurrent tumors. The prescribed radiation dose for the gross tumor and the elective nodal area was 69 Gy in 30 fractions and 51 Gy in 30 fractions, respectively. Results Radiation pneumonitis developed in 38 patients (76%, 38/50), and grade ≥2 radiation pneumonitis developed in 11 patients (22%, 11/50). The percentage of lung volume that received a dose in excess of 5 Gy (V5), V10, V20, V30, and the mean lung dose (MLD) in the bilateral and ipsilateral lung were significantly associated with the development of grade ≥2 radiation pneumonitis. Conclusion The incidence and degree of radiation pneumonitis are acceptable following treatment of NSCLC with VMAT.

OBJECTIVES The residual thoracic spaces (RTS) after pleurectomy/decortication (P/D) remain unexplored to date. Hence, this study aims to examine the details and risk factors of RTS during the 3 post-P/D months. METHODS We retrospectively examined patients who underwent neoadjuvant chemotherapy, followed by P/D for malignant pleural mesothelioma from September 2012 to December 2020. The RTS group included cases of residual thoracic cavity unaccompanied by pleural effusion on 3 postoperative months computed tomography. We determined risk factors for RTS using univariable and multivariable analyses. RESULTS Of 170 patients examined, 58 (34.1%) were in the RTS group and 112 (65.9%) in the non-RTS group. In the RTS group, 43 patients recovered from RTS during the follow-up period; 4 patients developed chronic fistular empyema, while 2 required fenestration and 2 were thoracoscopic debridement. Besides, 11 patients exhibited RTS continuously. The univariable analysis revealed that compared with the non-RTS group, the RTS group reported a significantly longer postoperative air leak (>7 days; P < 0.01) and right P/D (P = 0.04). The multivariable analysis demonstrated that longer postoperative air leak (>7 days) remained a risk factor for RTS (odds ratio 2.5, 95% confidence interval: 1.3–4.9, P < 0.01). CONCLUSIONS RTS was a postoperative event that frequently observed in patients undergoing P/D. Overall, the current study findings suggest longer postoperative air leak (>7 days) as a significant risk factor for RTS.

Objectives This study analyzed an artificial intelligence (AI) deep learning method with a three-dimensional deep convolutional neural network (3D DCNN) in regard to diagnostic accuracy to differentiate malignant pleural mesothelioma (MPM) from benign pleural disease using FDG-PET/CT results. Results For protocol A, the area under the ROC curve (AUC)/sensitivity/specificity/accuracy values were 0.825/77.9% (81/104)/76.4% (55/72)/77.3% (136/176), while those for protocol B were 0.854/80.8% (84/104)/77.8% (56/72)/79.5% (140/176), for protocol C were 0.881/85.6% (89/104)/75.0% (54/72)/81.3% (143/176), and for protocol D were 0.896/88.5% (92/104)/73.6% (53/72)/82.4% (145/176). Protocol D showed significantly better diagnostic performance as compared to A, B, and C in ROC analysis (p = 0.031, p = 0.0020, p = 0.041, respectively). Materials and methods Eight hundred seventy-five consecutive patients with histologically proven or suspected MPM, shown by history, physical examination findings, and chest CT results, who underwent FDG-PET/CT examinations between 2007 and 2017 were investigated in a retrospective manner. There were 525 patients (314 MPM, 211 benign pleural disease) in the deep learning training set, 174 (102 MPM, 72 benign pleural disease) in the validation set, and 176 (104 MPM, 72 benign pleural disease) in the test set. Using AI with PET/CT alone (protocol A), human visual reading (protocol B), a quantitative method that incorporated maximum standardized uptake value (SUVmax) (protocol C), and a combination of PET/CT, SUVmax, gender, and age (protocol D), obtained data were subjected to ROC curve analyses. Conclusions Deep learning with 3D DCNN in combination with FDG-PET/CT imaging results as well as clinical features comprise a novel potential tool shows flexibility for differential diagnosis of MPM.

Anticoagulation is recommended for the treatment of pulmonary embolism (PE) and deep vein thrombosis (DVT). In some cases, an inferior vena cava (IVC) filter is used to prevent PE. We report the case of a 70-year-old woman who developed non-massive PE and proximal DVT, which were treated using an IVC filter; two filters were placed owing to the fracture of the filters. Few previous reports have discussed IVC fractures and the difficulty in detecting such fractures on computed tomography before retrieval. Based on our experience, we suggest that a temporary IVC filter for DVT treatment should be considered carefully.

In recent years, there has been a shift from extrapleural pneumonectomy (EPP) toward pleurectomy/decortication (P/D) as the preferred surgical technique. However, we occasionally encounter difficult cases wherein visceral pleurectomy requires conversion to EPP from P/D. We sought to clarify the preoperative risk factors and clinical outcomes associated with conversion to EPP. We compared and analyzed conversion to EPP and P/D between September 2012 and December 2019. Conversion to EPP was decided in case of diffuse tumor invasion to the pulmonary parenchyma or due to failure of decortication. Univariable regression analysis was performed to determine the association of preoperative variables with conversion to EPP. Survival was analyzed by the Kaplan-Meier method and log-rank test. Of the 181 patients who underwent intended P/D, 145 (80.1%) patients underwent P/D and 18 (9.9%) patients underwent conversion to EPP. The sum of 3-level pleural thickness (P0.001), maximum of 3-level pleural thickness (P = 0.006), and clinical T stage (P0.001) demonstrated association with conversion to EPP. Overall survival and progression-free survival were significantly worse in the conversion to EPP group (median overall survival, 29.2 months vs 57.0 months [P = 0.008]; median progression-free survival, 15.3 months vs 23.2 months [P = 0.005]. Our data show that approximately 1 of every 10 patients with P/D intention converted to EPP. Preoperative pleural thickness and clinical T stage may be risk factors associated with conversion to EPP. The survival rate of conversion to EPP was worse than that of P/D.

Introduction Most patients with pancreatic metastasis from lung cancer are not candidates for surgical treatment because they have widespread systemic disease at the time of diagnosis. But it was reported that some patients with long-term survival were resected for pancreatic metastasis from lung cancer. We herein report a surgical case of pancreatic metastasis from lung cancer. Case Presentation A 61-year-old man was admitted to our hospital because of a lung tumor. He underwent right middle lobectomy. A histopathologic examination showed poorly differentiated adenocarcinoma. About 1 year after lung resection, brain metastasis was demonstrated and radiation therapy was subsequently performed. Seven years after lung resection, his serum carcinoembryonic antigen levels were again elevated. FDG–PET (fluorodeoxyglucose-positron emission tomography) showed a slight uptake by the pancreatic head. Computed tomography (CT) showed an irregular and poorly enhanced tumor in the pancreatic head. EUS–FNA (endoscopic ultrasonography fine-needle aspiration) of the tumor in the pancreatic head was performed. A histopathologic examination showed thyroid transcription factor (TTF)-1 positive adenocarcinoma. The preoperative diagnosis was pancreatic metastasis from lung cancer. We performed subtotal stomach-preserving pancreaticoduodenectomy for the pancreatic head tumor because the primary lung cancer and brain metastasis responded to chemoradiation. A histopathologic examination of the resected specimen revealed moderately differentiated adenocarcinoma. Immunohistochemistry revealed TTF-1 positive cells in the tumor. The patient was discharged from the hospital on the 12th day after surgery. He is currently alive 22 months after pancreatic surgery. Conclusion Resection of pancreatic metastasis from lung cancer may improve the patient outcome when the metastasis is localized in the pancreas or other organ metastases are controlled.

Surgical valve replacement improves the symptoms and prognosis of patients with valvular heart diseases. Aortic regurgitation elicits volume overload that causes enlargement of the left ventricle (LV), while the LV size often shrinks to near normal after aortic valve replacement (AVR), which is referred to as "reverse remodeling". We experienced a case in which LV outflow tract (LVOT) obstruction became apparent after AVR, resulting in worsening of heart failure. A 65-year-old man who had undergone surgical AVR for aortic valve regurgitation 15 months previously exhibited dyspnea on effort accompanied with severe LVOT obstruction. With double pressure catheters, we directly recorded an augmented pressure gradient in the LVOT and rapid relief of the obstruction by intravenous administration of the anti-arrhythmic drug cibenzoline. Since the considerable LV hypertrophy had been indicated by an electrocardiogram and echocardiography before AVR, we suspected that dilation of the LV chamber due to aortic valve regurgitation could have masked the subclinical LVOT obstruction, which became clinically evident after LV size reduction due to reverse remodeling after AVR.

BackgroundThe KEYNOTE-045 trial showed that pembrolizumab therapy improved the survival of patients with advanced urothelial carcinoma (UC). However, its effectiveness in trial-ineligible patients remains unclear.Materials and MethodsWe conducted a multicenter retrospective study to evaluate the effectiveness of pembrolizumab in patients with metastatic UC who were trial-ineligible. The data of 222 consecutive patients with platinum-treated metastatic UC who received pembrolizumab as second-line therapy were analyzed. Trial eligibility was assessed using the KEYNOTE-045 criteria. Inverse probability weighting (IPW) was used to balance patient characteristics. Overall survival (OS) and progression-free survival (PFS) were examined using the IPW-adjusted Kaplan-Meier method. IPW-adjusted restricted mean survival times (RMSTs) were compared between trial-ineligible and trial-eligible patients.ResultsOne hundred thirty-three patients (59.9%) were classified as trial-ineligible according to the KEYNOTE-045 criteria. Patients who did not develop progression following chemotherapy were the most common reason for trial protocol violation (N = 58 [26.1%]). The trial-ineligible patients showed similar RMST for PFS (difference: 2.4 months, 95% CI: -3.2 to 8.0, P = 0.40) and OS (difference: 1.7 months, 95% CI: -8.3 to 4.9, P = 0.60) compared with the trial-eligible patients. Furthermore, patients who were trial-ineligible because of comorbidities, poor performance status, or impaired liver or kidney function also had similar RMST for PFS and OS compared with those who were trial-eligible.ConclusionsThis study suggests that the effectiveness of pembrolizumab may be retained in trial-ineligible patients with platinum-treated metastatic UC. Expanding trial eligibility criteria for these patients may be beneficial.

Background Evaluation of tumor markers may facilitate follow-up of malignant pleural mesothelioma (MPM). We aimed was to evaluate the value of tumor markers for monitoring and predicting recurrence in patients with MPM. Methods In total, 152 patients who underwent curative-intent surgery after induction chemotherapy for MPM between July 2004 and December 2017 were retrospectively reviewed. Preoperative and postoperative (≤3 months after surgery) levels of soluble mesothelin-related peptide (SMRP), cytokeratin 19 fragment (Cyfra21-1), and tissue polypeptide antigen (TPA) and rates of recurrence and non-recurrence were evaluated. Factors associated with recurrence-free survival (RFS) were assessed using the Kaplan-Meier method and Cox proportional hazards model. Results Of the 152 patients, the positive rates of preoperative SMRP, Cyfra21-1, and TPA, levels were 26.7%, 8.6%, 9.6%, respectively; the respective postoperative levels were 4.0%, 6.3%, and 6.5%; the respective levels in patients with recurrence were 39.3%, 31.4%, 28.6%; the respective levels in patients with no recurrence were 3.7%, 0.0%, 3.8%. Nearly half (45.2%) of the patients with recurrence exhibited an increase in one or more tumor marker levels. Multivariate analysis revealed that the preoperative positive rates of one or more of the three tumor markers (hazard ratio: 1.8, 95% confidence interval: 1.1-2.8; P=0.02) were independent significant predictors of recurrence. Conclusions The positive rates of SMRP, Cyfra21-1, and TPA in recurrence-free patients were extremely low, with high specificity. Preoperative levels of SMRP, Cyfra21-1, and TPA, which identified patients with a high risk for recurrence, could improve management of patients with MPM.

A few studies have reported the incidence and clinical implications of complications after pleurectomy/decortication (P/D). The aim of this study was to assess the details of complications and predictive factors of particularly durable air leak with P/D. Data on 163 consecutive patients who underwent neoadjuvant chemotherapy (NAC) followed by P/D for malignant pleural mesothelioma between September 2012 and May 2020 at our institution were retrospectively analyzed. Postoperative complications and the significance of various preoperative risk factors for air leak > 10 days (AL10) to identify the group having a higher risk for particularly durable air leak were investigated. Risk factors for AL10 were sought using univariate and multivariate analyses. Of 163 patients, 30- and 90-day mortality was 0.6% and 2.5%, respectively. Eighty-four (51.4%) patients experienced grade III or worse postoperative complications according to the Clavien–Dindo classification. The median duration of air leak was 7 postoperative days. AL10 occurred in 53 (32.5%) patients. Fifty-eight patients (35.6%) underwent pleurodesis and five patients (3.1%) underwent reoperation to control the air leak. On univariate analysis, performance status (PS; p = 0.003), prognostic nutritional index (p = 0.01), and pleural effusion (p = 0.04) were statistically significant risk factors for AL10, while on multivariate analysis, PS (odds ratio 4.0, 95% confidence interval 1.3–12.7; p = 0.02) remained the only variable predicted for AL10. Recent postoperative mortality rates in NAC followed by P/D are quite acceptable. Approximately one in every three patients experienced AL10, and PS may be a risk factor associated with AL10.

We occasionally encounter malignant pleural mesothelioma (MPM) of no apparent tumor or pleural thickening that is radiological early MPM. This study aimed to examine the clinicopathological outcomes of radiological early MPM. Patients with MPM treated with neoadjuvant chemotherapy and planned surgery at the time of diagnosis between July 2004 and December 2019 were retrospectively examined. Pretreatment maximal pleural thickness of all patients was measured on chest computed tomography. We extracted and investigated the patients who exhibited a lack of pleural thickening or visible tumor, which was defined as radiological early MPM. Survival was analyzed by the Kaplan–Meier method. Of 296treated patients, 16 (5.4%) exhibited radiological early MPM. Fourteen (87.5%) of these patients underwent pleurectomy/decortication and 2 (12.5%) underwent extrapleural pneumonectomy. Pathological stage T1 disease was diagnosed in 14 (87.5%) patients; 2 (12.5%) exhibited pulmonary parenchymal invasion (pathological stage T2). Lymphatic invasion was detected in only 1 patient. Lymph node metastases and vascular invasion were not detected. Median follow-up was 42 months. Median progression-free survival and median overall survival were 40.7 and 56.1 months, respectively. The 3-year progression-free survival and overall survival rates were 84.8% and 83.6%, respectively. Radiological early MPM occurs in approximately 1 of every 20 patients treated with neoadjuvant chemotherapy and surgery planned at the time of diagnosis in an experienced center. Radiological early MPM was associated with early pathological stage and long-term survival.

Fracture and drop-off of diamond grains are thought to be suppressed if the diamond grains used, such as those for electroplated wires, are coated with a material having a higher coefficient of thermal expansion than diamond and having good adhesion to the binder metal. In this study, we selected titanium carbide and titanium carbonitride as materials with such characteristics, and investigated their coating methods. The titanium carbide coating was formed by heating a mixture of diamond plate or diamond grains and titanium powder in vacuum at a temperature lower than the melting point of titanium. Titanium carbonitride formation tests were performed in two ways: by forming a titanium carbide coating and titanium carbonitride in the same chamber continuously or by exposing the sample to the atmosphere after titanium carbide formation and subsequently reheating it in nitrogen. The titanium carbide coating was tested by heating the mixture of the diamond plate and the titanium grains in vacuum of 2.0 × 10−3 Pa or less at 1073–1273 K for 60–120 min. For the titanium carbonitride coating, the primary titanium carbide coating was applied at temperatures of 1123–1273 K for 60 min. Then the titanium carbonitride formation was done at the same temperature but with different heating times. Products on the diamond after heating tests were analyzed using X-ray diffraction. Results show that titanium carbide can be coated onto the diamond surface by heating the mixture of diamond and titanium powder in vacuum at 1073 K or at a higher temperature. Results demonstrated further that titanium carbonitride can be formed by heating the diamond plate or the diamond grains coated with titanium carbide in nitrogen at a temperature higher than 1123 K. The titanium carbide layer thickness and the ratio of nitrogen in the titanium carbonitride increased concomitantly with increased heating temperature and increased heating time.

Background Multisite pain, including low-back and knee pain, is a major health issue that greatly decreases quality of life. Objectives This study analyzed the effects of l-serine, which provides necessary components for nerve function, and EPA, which exerts anti-inflammatory properties, on pain scores of adults with pain in at least the low back and knee for ≥3 mo. Methods This was a randomized, double-blind, placebo-controlled, parallel-group study. The Japan Low Back Pain Evaluation Questionnaire (JLEQ) and Japanese Knee Osteoarthritis Measure (JKOM) were applied as primary outcomes. The Brief Pain Inventory (BPI) and safety evaluation were secondary outcomes. We enrolled 120 participants aged ≥20 y (36 men and 84 women: mean ± SD age = 40.8 ± 10.9 y). The participants were randomly allocated to either the active group (daily ingestion of 594 mg l-serine and 149 mg EPA) or placebo group. The study period consisted of 8-wk dosing and 4-wk posttreatment observation. ANCOVA between groups for each time point was conducted using the baseline scores as covariates. Results The JLEQ scores (active compared with placebo: 14.2 ± 11.2 compared with 19.0 ± 10.2) at week 8 were lower in the active group (P

Ammonia is an indispensable chemical. Photocatalytic NH3 production via dinitrogen fixation using water by sunlight illumination under ambient conditions is a promising strategy, although previousl...

Wolffia is a genus of protein-rich aquatic plants. Mankai, a cultivated strain of Wolffia globosa, contains more than 40 % protein based on dry matter evaluation. Furthermore, Mankai is nutritionally excellent as a food material, and is expected to be applicable to various products as a substitute for animal protein. A battery of toxicological studies was conducted on the dried product of Mankai (Dry Mankai), with the expectation to utilize it as a raw material for food applications. Dry Mankai was not genotoxic in a bacterial reverse mutation test and in vitro micronucleus assay. In the subchronic toxicity study, rats were provided Dry Mankai in the diet at levels of 0 %, 5 %, 10 %, or 20 % (w/w), equivalent to 0, 3.18, 6.49, and 13.16 g/kg/day for males and 0, 3.58, 7.42, and 15.03 g/kg/day for females, respectively. No adverse effects that could be attributable to treatment were observed in clinical observations, body weight, food consumption, ophthalmology, hematology and blood chemistry, urinalysis, and macroscopic and microscopic findings. According to the repeated-dose study in rats, the no observed adverse effect level of Dry Mankai was 20 % (w/w) for both sexes (13.16 and 15.03 g/kg/day for males and females, respectively).