Differences in drug sensitivity between two-dimensional and three-dimensional culture systems in triple-negative breast cancer cell lines.

Three-dimensional (3D) culture reflects tumor biology complexities compared with two-dimensional (2D) culture. Thus, 3D culture has attracted attention in cell biology studies including drug sensitivity tests. Herein, we investigated differences in anticancer drug sensitivities between 2D and 3D culture systems in triple-negative breast cancer (TNBC) cell lines. Thirteen TNBC cell lines were maintained in 2D and 3D cultures for 3 days before drug exposure. Cell morphology in the 3D culture was examined by phase-contrast microscopy. Sensitivities to epirubicin (EPI), cisplatin (CDDP), and docetaxel (DTX) were investigated by cell viability assay in both cultures and compared. The IC50s of all 3 drugs were significantly higher in the 3D culture than in the 2D culture in most cell lines. Those were correlated between the 2D and 3D cultures in EPI (R = 0.555) and CDDP (R = 0.955), but not in DTX (R = 0.221). Round spheroid-forming cells were more resistant to agents than grape-like types. In conclusion, 3D culture was more resistant to all 3 drugs than 2D culture in most TNBC cell lines. Sensitivity to CDDP was highly correlated between the 2D and 3D cultures, but not to DTX. 2D culture may be acceptable for sensitivity test for DNA-damaging agents.

Therapeutic potential of PLK1 inhibition in triple-negative breast cancer.

Triple negative breast cancer (TNBC) is responsible for significant number of breast cancer-associated deaths because of lacking of successful molecular-targeted therapy. To explore a therapeutic target for TNBC, we performed a siRNA-mediated knockdown screening and identified Polo-like kinase 1 (PLK1) as a potential therapeutic target for TNBC. Knockdown of PLK1 as well as a small compound inhibitor for PLK1, BI-2536, induced G2/M arrest and created polyploid cell population, shown by increased DNA content and nuclear size. Inhibition of PLK1 eventually triggered apoptosis in multiple TNBC cell lines. In addition, we confirmed that PLK1 was significantly overexpressed in the tissues from TNBC patients compared with the tissues of normal mammary glands and benign breast tumors. Our data indicated that PLK1 plays a pivotal role in the regulation of mitosis of TNBC cells. Although future in vivo studies are warranted, targeting PLK1 by a selective inhibitor such as BI-2536 can be an attractive molecular-targeted therapy for TNBC.

Factors related to prevalence of hallux valgus in female university students: a cross-sectional study.

BACKGROUND: We investigated the prevalence of hallux valgus (HV) and examined its association with various factors in a cross-sectional study of Japanese female university students. METHODS: A questionnaire survey of foot symptoms, lifestyle, and body mass index (BMI) was administered to 343 women who provided informed consent at a women's university. Footprints were obtained and bone density was measured. Associations of HV with various factors were analyzed by logistic regression analysis. RESULTS: Big toe pain was reported in 26.5% of the women. HV (HV angle, ≥15°) was present in the left foot in 22.4%, the right foot in 20.7%, and unilaterally or bilaterally in 29.7% of women. Mild HV (HV angle, ≥15° to <20°) was noted in the left foot and right foot in 13.4% and 13.1% of women, respectively; no severe HV (HV angle, ≥40°) was observed. HV was associated with big toe pain (adjusted OR: 3.56, 95% CI: 2.01-6.32), history of HV in the mother or maternal grandmother (adjusted OR: 2.45, 95% CI: 1.19-5.02), and history of HV in other family members (adjusted OR: 3.09, 95% CI: 1.35-7.06). Moderate HV was associated with big toe pain (adjusted OR: 4.58, 95% CI: 2.17-9.66) and history of HV in the mother or maternal grandmother (adjusted OR: 3.36, 95% CI: 1.40-8.07). The proportion of women with big toe pain increased significantly with HV severity. CONCLUSIONS: HV was present in about 30% of female university students. Young women with big toe pain or a family history of HV should be evaluated for HV.

TP53 signature predicts pathological complete response after neoadjuvant chemotherapy for breast cancer: Observational and confirmational study using prospective study cohorts.

The TP53 signature is considered a predictor of neoadjuvant chemotherapy (NAC) response and prognostic factor in breast cancer. The objective of this study was to confirm TP53 signature can predict pathological complete response (pCR) and prognosis in cohorts of breast cancer patients who received NAC in prospective studies. Development cohorts (retrospective [n = 37] and prospective [n = 216] cohorts) and validation cohorts (NAC administered prospective study cohorts [n = 407] and retrospective perioperative chemotherapy (PC)-naïve, hormone receptor (HrR)-positive cohort [PC-naïve_HrR+ cohort] [n = 322]) were used. TP53 signature diagnosis kit was developed using the development cohorts. TP53 signature predictability for pCR and the relationship between recurrence-free survival (RFS), overall survival (OS), and the TP53 signature were analyzed. The pCR rate of the mutant (mt) signature group was significantly higher than that of the wild-type (wt) signature group (odds ratio, 5.599; 95 % confidence interval = 1.876-16.705; P = 0.0008). The comparison of the RFS and OS between the HrR+ and HER2- subgroup of the NAC cohort and of the PC-naïve_HrR+ cohort indicated that the RFS and OS benefit of NAC was greater in the mt signature group than in the wt signature group. From post hoc analyses, the RFS and OS benefit from adding capecitabine to FEC+T as NAC might be observed only in the mt signature group. The TP53 signature can predict the pCR after NAC, and the RFS and OS benefit from NAC may be greater in the mt signature group than in the wt signature group.

Accuracy and validity of sentinel lymph node biopsy for breast cancer using a photosensitizer: 8-year follow-up.

BACKGROUND AND OBJECTIVE: We evaluated an alternative procedure for sentinel lymph node biopsy (SLNB) for breast cancer after approval of the study by the Ethics Committee of Tokyo Medical University Hospital in 2004. We examined the efficacy and safety of SLNB using the photosensitizer talaporfin sodium (Laserphyrin®, Meiji Seika Pharma, Tokoyo, Japan), compared with current methods. STUDY DESIGN/PATIENTS AND METHODS: The study included 21 breast cancer patients (Japanese women; median age, 54 years; range, 35-75). All patients received a breast cancer operation combined with SLNB between June 2004 and May 2005. Three milliliters of talaporfin solution was locally injected into the subareolar region just before the operation. We attempted to identify a sentinel lymph node (SLN) that exhibited fluorescence and was consistent with a radioisotope (RI) localization technique. Our purpose was to verify the accuracy and validity of the talaporfin fluorescence imaging method after 8 years of application. RESULTS: There was no consistent correlation between fluorescence and pathological SLN metastasis, although all four cases of pathological SLN metastasis revealed positive fluorescence. In some cases in which we could not identify SLNs by the RI technique, we could identify SLNs using talaporfin. The method using talaporfin did not adversely affect the patients after the operation, even the chronic renal failure patient. After 8 years, all patients are alive, and none had lymph node recurrence. Side effects were not observed. CONCLUSION: SLNB using the photosensitizer talaporfin sodium in breast cancer patients is considered to be useful as complementary to other current methods. We could evaluate the accuracy and validity of this method 8 years after all of the procedures were performed. In the future, a large-scale clinical study with statistical analyses should be conducted.

[Imaging brain activity in virtual reality: abnormal hippocampal cognitive maps in autism model mice].

The symptoms and behavioral abnormalities of brain diseases are thought to be caused by the dysfunction of neural circuits formed by numerous neurons. Virtual reality (VR) is used for behavioral tasks under head fixation and has the advantage of precise control of experimental conditions. In this review, we first overview the application of VR in rodent neuroscience, introduce our research on two-photon calcium imaging of the hippocampus of autism spectrum disorder (ASD) model mice navigating a VR environment, and then discuss how hippocampal dysfunction can relate to ASD phenotypes. By combining a VR system with two-photon microscopy, we clarified the formation of hippocampal CA1 place cell maps in mice undergoing spatial learning in VR. As mice learned, the number of place cells increased, and the density of cells that responded to places with behaviorally relevant features such as rewards and landmarks increased more than cells active elsewhere. Furthermore, many stable place cells responded at landmark and reward locations. Shank2-deficient ASD model mice spent more time running and received more rewards. In their hippocampal maps, the proportion of cells active at landmarks did not increase, whereas the proportion of cells active at rewards excessively increased. Individuals with ASD are known to show unique tendencies in their perception and cognition of the world around them, but the detailed brain mechanisms remain unclear. It is thus possible that some ASD cases involve cognitive mapping abnormalities, such as the distortion of hippocampal information representation that our study revealed.

Delayed Diagnosis and Prognostic Impact of Breast Cancer During the COVID-19 Pandemic.

BACKGROUND: Breast screening services were suspended for several months owing to the coronavirus disease 2019 (COVID-19) pandemic. We estimated the potential impact on breast cancer mortality using long-term global observations. However, the magnitude of the impact may vary across countries; therefore, we conducted an analysis and modeling study of this impact in Japan. PATIENTS AND METHODS: We compared the clinicopathological features of breast cancers between the nonpandemicgroup (April 1, 2019 to October 31, 2019) and the pandemic group (April 1, 2020 to October 31, 2020). We also compared the estimated 10-year survival rates between the two groups based on the weighted average of the 10-year survival rate by clinical stage and site (2004-2007). RESULTS: Results...Pandemic-related disruption decreased the number of breast cancer cases from296 to 249 during both 7-month periods. The percentage of patients with stage IIB or higher disease was significantly higher in the pandemic group than in the non-pandemic group (22.0% vs. 31.3%, P = 0.0133). The percentage of cases with a Ki-67 labeling index higher than 20% tended to be higher in the pandemic group than in the non-pandemic group (62.2% vs. 54.4%). The estimated 10-year survival rate was lower in the pandemic group than in the non-pandemic group (83.9% vs. 87.9%, 95% confidence interval of the difference: 0.87-8.8, P > 0.05). CONCLUSION: We found more aggressive and advanced disease afterthe suspension of breast cancer screening services owing to the COVID-19 pandemic. This may have affected the long-term clinical outcomes of patients with breast cancer.

Development of multiple AI pipelines that predict neoadjuvant chemotherapy response of breast cancer using H&E-stained tissues.

In recent years, the treatment of breast cancer has advanced dramatically and neoadjuvant chemotherapy (NAC) has become a common treatment method, especially for locally advanced breast cancer. However, other than the subtype of breast cancer, no clear factor indicating sensitivity to NAC has been identified. In this study, we attempted to use artificial intelligence (AI) to predict the effect of preoperative chemotherapy from hematoxylin and eosin images of pathological tissue obtained from needle biopsies prior to chemotherapy. Application of AI to pathological images typically uses a single machine-learning model such as support vector machines (SVMs) or deep convolutional neural networks (CNNs). However, cancer tissues are extremely diverse and learning with a realistic number of cases limits the prediction accuracy of a single model. In this study, we propose a novel pipeline system that uses three independent models each focusing on different characteristics of cancer atypia. Our system uses a CNN model to learn structural atypia from image patches and SVM and random forest models to learn nuclear atypia from fine-grained nuclear features extracted by image analysis methods. It was able to predict the NAC response with 95.15% accuracy on a test set of 103 unseen cases. We believe that this AI pipeline system will contribute to the adoption of personalized medicine in NAC therapy for breast cancer.

Caffeic acid phenethyl ester suppresses the production of pro-inflammatory cytokines in hypertrophic adipocytes through lipopolysaccharide-stimulated macrophages.

Obesity is a condition in which excess body fat accumulates due to lipids producing adipocytes and an increased number of differentiated mature cells. Recently, new findings have shown that macrophages infiltrate into adipose tissues and produce various pro-inflammatory cytokines in obese subjects. The inflammatory changes induced by the cross-talk between adipocytes and macrophages are critical for the pathophysiology of obesity and thus of metabolic syndrome. Caffeic acid phenethyl ester (CAPE) is known to have many functions, including antibacterial, anticancer and anti-inflammatory properties, but there is no evidence of its effect on the inflammatory responses in hypertrophic adipocytes through stimulation by macrophages. We investigated the effect of CAPE on macrophages and hypertrophic adipocytes in this study. CAPE significantly suppressed the levels of lipopolysaccharide (LPS)-induced interleukin (IL)-1-beta, tumor necrosis factor (TNF)-alpha and monocyte chemoattractant protein (MCP)-1 from a macrophage cell line, RAW264.7. Supernatants of stimulated RAW264.7 macrophages drastically increased mRNA levels of pro-inflammatory cytokines such as IL-6, MCP-1 and TNF-alpha in 3T3-L1 hypertrophic adipocytes. CAPE also significantly and dose-dependently reduced the gene expression of these cytokines. Our findings indicate that CAPE has inhibitory effects on the production of pro-inflammatory cytokines from LPS-stimulated RAW264.7 macrophages. In addition, CAPE suppressed gene expressions of cytokines under inflammatory conditions of hypertrophic adipocytes, suggesting that it may have the potential to suppress inflammation by macrophage infiltration into adipose tissue in obese patients.

Beneficial effects of transdermal administration of tamoxifen on capsular contracture after breast implantation in murine models.

BACKGROUND AND AIM: Capsular contracture is the most common complication with smooth-type silicone implants. We investigated the preventive effect of an active metabolite of tamoxifen, 4-hydroxytamoxifen (4-OH TAM), on capsular contracture. METHODS: A silicone sheet was implanted into the back of 28 female ICR mice. Mixtures of gel with 0.2% 4-OH TAM and 0.1% 4-OH TAM were administered transdermally once a day for 4 weeks. Saline was administered to the control. After killing the mice, capsular thickness was measured in H&E-stained specimens. Estrogen receptor (ER), α-smooth muscle actin (α-SMA), and transforming growth factor-ß (TGF-ß) expressions were immunohistochemically investigated in the capsules. RESULTS: The capsule was thinner in the 0.2% 4-OH TAM gel group than in the control group (control, 0.1% 4-OH TAM gel, 0.2% 4-OH TAM gel: 52.8 ± 3.4 µm, 54.2 ± 6.8 µm, 46.4 ± 3.3 µm, respectively). ER was found in most fibroblasts of all samples. α-SMA expression in the capsule was significantly lower in the 4-OH TAM gel groups than in the control group (control = 70.0 ± 3.4%, 0.1% 4-OH TAM = 57.0 ± 3.4%, 0.2% 4-OH TAM = 49.4 ± 4.9%). TGF-ß expression was significantly reduced by the 4-OH TAM gel injections dose-dependently (control = 67.3 ± 2.2%, 0.1% 4-OH TAM = 52.4 ± 3.1%, 0.2% 4-OH TAM = 45.1 ± 2.4%). CONCLUSIONS: The transdermal administration of 0.1% and 0.2% 4-OH TAM gels inhibited capsule development. The inhibition of TGF-ß expression is a mechanism by which 4-OH TAM suppresses fibroblast growth, preventing capsular formation.

Caffeic acid phenethyl ester suppresses the production of adipocytokines, leptin, tumor necrosis factor -alpha and resistin, during differentiation to adipocytes in 3T3-L1 cells.

We previously reported that caffeic acid phenethyl ester (CAPE) suppresses 3T3-L1 differentiation to adipocytes through the inhibition of peroxisome proliferator-activated receptor (PPAR) gamma, CCAAT/enhancer-binding protein (C/EBP) alpha, fatty acid synthase (Fas) and adipocytes-specific fatty acid binding protein 2 (aP2) expressions (Juman et al., Biol. Pharm. Bull., 33, 1484-1488 (2010)). In the present study, we confirmed that CAPE had inhibitory effects on increased glycerol-3-phosphate dehydrogenase (GPDH) activity and an increased insulin receptor substrate 1 (IRS-1). Our data show that treatment with 50 µM CAPE significantly reduced the levels of leptin (p<0.05), resistin (p<0.05) and tumor necrosis factor (TNF)-alpha (p<0.05) which are known to aid adipocytokines production in adipocytes. In 3T3-L1 cells, treatment of CAPE decreased the triglyceride deposition similar to resveratrol, which is known to have an inhibitory effect on 3T3-L1 differentiation to adipocytes. In conclusion, we found that CAPE suppresses the production and secretion of adipocytokines from mature adipocytes in 3T3-L1 cells.

A case of hereditary metachronous bilateral triple-negative breast cancer that was highly sensitive to carboplatin.

A 52-year-old woman with a strong family history of breast cancer was diagnosed as having triple-negative breast cancer (TNBC) in her right breast. Neoadjuvant chemotherapy (NAC; four cycles of epirubicin/cyclophosphamide/5-fluorouracil) was performed, followed by breast-conserving surgery and axillary lymph node dissection. Histopathological analysis of the surgical specimens demonstrated a few focal tumor cells remaining in the stroma, but not a pathological complete response (pCR). Weekly paclitaxel was subsequently added to the treatment regimen. A total of 17 months after the adjuvant treatments, TNBC recurred in her left breast with massive lymph node metastasis. Because of the early recurrence after standard treatment, NAC was administered together with carboplatin and paclitaxel. Histopathological analysis of the partially resected breast and axillary lymph nodes demonstrated a pCR. No recurrent disease was found 2 years after the second TNBC treatment. This case underlines the importance of platinum-based chemotherapy and prophylactic mastectomy for patients with BRCA dysfunction.

Successful treatment of G-CSF-related aortitis with prednisolone during preoperative chemotherapy for breast cancer: a case report.

BACKGROUND: With the introduction of dose-dense therapy, the use of primary pegfilgrastim (PEG-G) has been increasing in breast cancer treatment. A rare side effect of PEG-G is aortitis. We describe a case of PEG-G-induced aortitis. CASE PRESENTATION: The patient was a 43-year-old woman with stage IIA breast cancer. Due to the subtype of triple-negative breast cancer, preoperative dose-dense epirubicin-cyclophosphamide chemotherapy was started. PEG-G was administered on day 3 after the first cycle of epirubicin-cyclophosphamide chemotherapy. On day 11, she had a fever (39.4 °C) and an elevated C-reactive protein level (27.1 mg/dL). Emergency computed tomography revealed diffused wall thickening of the aortic arch without any other signs of infection. Despite administering antibiotics, her general condition and laboratory findings deteriorated until day 18. Based on these observations, she was diagnosed with PEG-G-induced aortitis. Antibiotics were discontinued, and she was treated with prednisolone thereafter. Subsequently, her clinical symptoms and laboratory findings improved around day 39. A second computed tomography scan revealed a decrease in the aortic arch wall thickening, and she was discharged on day 43. CONCLUSIONS: We successfully treated PEG-G-induced aortitis using prednisolone. Although this side effect is rare, cancer patients receiving PEG-G for chemotherapy should be monitored for aortic inflammation.

Caffeic acid phenethyl ester inhibits differentiation to adipocytes in 3T3-L1 mouse fibroblasts.

We investigated the inhibitory effect of caffeic acid phenethyl ester (CAPE) on the differentiation of 3T3-L1 mouse fibroblasts to adipocytes. 3T3-L1 cells were differentiated for adipocytes given high glucose Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS), 1 microM dexamethasone (DEX), 500 microM isobutylmethylxanthine (IBMX), and 5 microg/ml insulin for 7 days. After differentiation, cells were stained with Oil-Red-O to detect oil droplets in adipocytes. Additionally, the cells were lysed and measured for triglyceride contents. Total RNA was isolated from differentiated cells on day 0, 4 and 7. Then, RNA was analyzed using reverse transcription (RT)-polymerase chain reaction (PCR). CAPE dose-dependently suppressed oil droplet accumulation and reduced the droplet size. These findings showed that CAPE at concentrations of 25 to 50 microM could significantly inhibit triglyceride deposition (p<0.05). Treatment of 3T3-L1 with CAPE reduced the mRNA levels of peroxisome proliferator-activated receptor (PPAR) gamma and CCAAT/enhancer-binding protein (C/EBPalpha). Fatty acid synthase (Fas) and adipocyte-specific fatty acid binding protein (aP2) are known to be associated with lipid metabolism in adipocytes, and both Fas mRNA and aP2 mRNA were significantly suppressed by CAPE treatment. These findings suggested that CAPE suppresses 3T3-L1 differentiation to adipocytes through inhibition of PPARgamma, C/EBPalpha, Fas and aP2 expression.

In Vitro Studies to Define the Cell-Surface and Intracellular Targets of Polyarginine-Conjugated Sodium Borocaptate as a Potential Delivery Agent for Boron Neutron Capture Therapy.

Boron neutron capture therapy (BNCT) requires pharmaceutical innovations and molecular-based evidence of effectiveness to become a standard cancer therapeutic in the future. Recently, in Japan, 4-borono-L-phenylalanine (BPA) was approved as a boron agent for BNCT against head and neck (H&N) cancers. H&N cancer appears to be a suitable target for BPA-BNCT, because the expression levels of L-type amino acid transporter 1 (LAT1), one of the amino acid transporters responsible for BPA uptake, are elevated in most cases of H&N cancer. However, in other types of cancer including malignant brain tumors, LAT1 is not always highly expressed. To expand the possibility of BNCT for these cases, we previously developed poly-arginine peptide (polyR)-conjugated mercaptoundecahydrododecaborate (BSH). PolyR confers the cell membrane permeability and tumor selectivity of BSH. However, the molecular determinants for the properties are not fully understood. In this present study, we have identified the cluster of differentiation 44 (CD44) protein and translational machinery proteins as a major cell surface target and intracellular targets of BSH-polyR, respectively. CD44, also known as a stem cell-associated maker in various types of cancer, is required for the cellular uptake of polyR-conjugated molecules. We showed that BSH-polyR was predominantly delivered to a CD44High cell population of cancer cells. Once delivered, BSH-polyR interacted with the translational machinery components, including the initiation factors, termination factors, and poly(A)-biding protein (PABP). As a proof of principle, we performed BSH-polyR-based BNCT against glioma stem-like cells and revealed that BSH-polyR successfully induced BNCT-dependent cell death specifically in CD44High cells. Bioinformatics analysis indicated that BSH-polyR would be suitable for certain types of malignant tumors. Our results shed light on the biochemical properties of BSH-polyR, which may further contribute to the therapeutic optimization of BSH-BNCT in the future.

Effects of several virucidal agents on inactivation of influenza, Newcastle disease, and avian infectious bronchitis viruses in the allantoic fluid of chicken eggs.

General theories on the inactivation of viruses in the presence of a concentrated protein, such as the allantoic fluid of chicken eggs, are not useful. That is, although sodium hypochlorite and sodium hydroxide are generally known as strong virucidal agents, they do not sufficiently inactivate viruses in allantoic fluid. We found that benzalkonium chloride (BC) is an effective virucidal agent against influenza, Newcastle disease, and avian infectious bronchitis viruses even in the presence of a concentrated protein. BC is easily biodegradable by activated sludge and is not very harmful to humans. We strongly recommend BC as a useful virucidal agent, especially in the manufacture of vaccines for these viruses.

Hereditary breast cancer associated with Cowden syndrome-related PTEN mutation with Lhermitte-Duclos disease.

BACKGROUND: Cowden syndrome is characterized by multiple hamartomas in various tissues, including the skin, brain, breast, thyroid, mucous membrane, and gastrointestinal tract, and is reported to increase the risk of malignant disease. CASE PRESENTATION: We describe the case of a 52-year-old woman in whom a tumor was diagnosed in the left cerebellar hemisphere and treated by surgical resection. Phosphatase and tensin homolog (PTEN) mutation in exon 8 insertion was found in the brain tumor tissue and leukocytes. This finding supported the diagnosis of Cowden syndrome. She consequently developed endometrial cancer and underwent abdominal total hysterectomy with bilateral salpingo-oophorectomy. Four years later, hormone receptor-positive breast cancer was found in the right breast, and breast-conserving surgery with radiation therapy and sentinel lymph node biopsy was performed. CONCLUSIONS: Herein, we describe a patient who was diagnosed as having familial breast cancer associated with PTEN mutation-related Cowden syndrome. We also reviewed reports of this syndrome in the literature for disease appraisal.

Radiation exposure during sentinel lymph node biopsy for breast cancer: effect on pregnant female physicians.

BACKGROUND: The radionuclide (RN) method employed for sentinel lymph node biopsy is generally safe for adult medical care workers. However, the number of pregnant medical care workers who attend surgery has recently been increasing, along with the increasing number of female surgeons. In particular, female surgeons are concerned about the position of a surgeon's lower abdominal region being close to the RN injection site. We measured the exposure dose of the lower abdominal region in medical care workers and investigated the possible exposure effect on fetuses. METHODS: A dose of (99m)Tc-phytic acid (37 MBq) was subcutaneously injected into the areola of the nipple of patients. Scintigraphy and surgery were performed after 1 and 4 h, respectively. At the time of the local injection, a personal dosimeter measured the exposure dose in the surgeon, first and second assistants, anesthesiologist, and scrub nurse. RESULTS: The median exposure doses were 3, 1, 1, 0, and 0 µSv in the surgeon, first and second assistants, anesthesiologist, and scrub nurse, respectively. Protective clothing reduced the mean exposure dose by 66 %. CONCLUSIONS: In surgeons, the exposure dose from daily life activities (1 mSv/year) corresponds to the dose received after performing 333 surgeries (using 3 µSv as the median). However, the maximum value measured was 24 µSv; at this value, the total exposure dose exceeds 1 mSV in the 42nd surgery. Medical care workers can further reduce their exposure dose by paying attention to the surgical procedure and to their posture and position.