ABSTRACT
This study experimentally investigated acoustically driven gas-mixture separation. Acoustic wave propagation in a narrow tube can induce gas-mixture separation. A binary mixture of helium and argon was used as the gas mixture. The pressure amplitude of the acoustic wave and initial molar fraction of the helium gas were investigated. The obtained experimental data indicated that the molar fraction initially increased with increasing pressure amplitude, whereas the saturated molar fraction did not show a clear dependence on the pressure. Although the degree of separation was smaller with purer helium, gas-mixture separation occurred under all conditions within the experimental range.
ABSTRACT
This study proposes a time-evolution method to simulate acoustic gas-mixture separation. The proposed method can calculate the separation process without any arbitrary parameters except for space and time resolutions. The molar-fraction distribution within the system during the separation can be calculated, and the results show that a large molar-fraction gradient occurs in the separation tube, while a distribution also occurs in the resonance tube. Although the simulation results for the case with a high-pressure amplitude diverge from that of the experiment during the process of the separation, the simulation results for the case with a low-pressure amplitude agree well with those of the experiment.
ABSTRACT
Radiation-related normal tissue injury sustained during cancer radiotherapy or in a radiological or mass casualty nuclear incident is a major health concern. Reducing the risk and mitigating consequences of radiation injury could have a broad impact on cancer patients and citizens. Efforts to discover biomarkers that can determine radiation dose, predict tissue damage, and aid medical triage are underway. Exposure to ionizing radiation causes changes in gene, protein, and metabolite expression that needs to be understood to provide a holistic picture for treating acute and chronic radiation-induced toxicities. We present evidence that both RNA (mRNA, microRNA, long noncoding RNA) and metabolomic assays may provide useful biomarkers of radiation injury. RNA markers may provide information on early pathway alterations after radiation injury that can predict damage and implicate downstream targets for mitigation. In contrast, metabolomics is impacted by changes in epigenetics, genetics, and proteomics and can be considered a downstream marker that incorporates all these changes to provide an assessment of what is currently happening within an organ. We highlight research from the past 10 years to understand how biomarkers may be used to improve personalized medicine in cancer therapy and medical decision-making in mass casualty scenarios.
Subject(s)
MicroRNAs , Neoplasms , Radiation Injuries , Humans , Radiation Injuries/etiology , Radiation Injuries/genetics , MicroRNAs/genetics , Biomarkers , Epigenesis, Genetic , Neoplasms/genetics , Neoplasms/radiotherapy , RadiometryABSTRACT
Understanding clay flotation mechanisms has become a major concern because of the increasing level of environmental contamination of soil and ground water by heavy metals and radionuclides. Clays are often used as sorbents for extracting metals in indirect flotation processes but can function simultaneously as defoamers. However, how foam generation and stability depend on the molecular interactions between the clays and surfactant is still controversial. In the present study, an amine polyethoxylated surfactant was used as a bifunctional surfactant that collected clay particles and acted as a foaming agent in the flotation process. The pH conditions strongly affected the surfactant physicochemical properties, allowing the clay extraction efficiency to be tuned. The interfacial recovery factor of the clays almost reached 100% under acidic (pH < 6) and neutral (pH 6-10) conditions, whereas it was negative under alkaline conditions (pH > 10), contrary to expectations. To elucidate the mechanisms involved in the particle flotation process for each of the pH conditions, the bulk and foam phases were analyzed. The effects of electrostatic interactions between the solutes and multiscale structure on the clay extraction behavior were investigated by electrophoretic measurements, dynamic light scattering, small-angle neutron scattering, and image analysis. Based on these results, three flotation processes were found depending on pH range: surfactant foam fractionation at pH > 10; clay particle foam flotation at pH 6-10; and particle froth flotation at pH < 6.
ABSTRACT
BACKGROUND: Hydrocephalus is one of the most common presentations of occipital encephaloceles and usually develops within the first year of life. This case report presents a rare case of late-onset obstructive hydrocephalus associated with occipital encephalocele with an extraordinarily large occipital skull defect. CASE REPORT: At birth, a newborn girl presented with an absence of a vast amount of occipital cranium and skin and was diagnosed with occipital hydroencephalomeningocele. Under meticulous sterile management, the affected area was successfully epithelialized, and the patient was discharged without infectious complication. Despite an obstructed cerebral aqueduct, she grew without any signs of hydrocephalus until the age of 7 years. Her gait gradually worsened, and imaging tests at the age of 8 years revealed markedly enlarged lateral and third ventricles but not the fourth ventricle. Endoscopic third ventriculostomy successfully relieved her symptoms with improvement of hydrocephalus. CONCLUSION: This is the first case of late-onset obstructive hydrocephalus associated with an occipital encephalocele characterized by large-scale cranial bony defects. Although further investigation is required to elucidate the mechanism of hydrocephalus, this rare phenomenon should be noted during neurological and radiological follow-up.
Subject(s)
Hydrocephalus , Third Ventricle , Humans , Female , Infant, Newborn , Child , Ventriculostomy/methods , Encephalocele/surgery , Hydrocephalus/surgery , Cerebral Aqueduct/surgery , Third Ventricle/surgery , Skull/surgeryABSTRACT
A 70s woman with advanced rectal cancer(AV 3 cm, type 2)was diagnosed as cT3N2M1a, Stage â £(UICC, TNM 8th) and underwent total neoadjuvant therapy(TNT)consisted of preoperative 5 Gy×5 short course RT followed by 5 courses of CAPOX plus BEV and CAPOX. Post-treatment endoscopy revealed nearCR, MRI failed to identify the primary tumor, and the mesenteric and lateral lymph node enlargement had disappeared. The patient underwent robot-assisted low anterior resection, bilateral lymph node dissection, and temporary ileal colostomy. Postoperative pathological findings were ypT0N0M0, Stage 0, and the efficacy evaluation was TRG 0(AJCC)with no residual tumor including lateral lymph nodes. The patient was discharged on the 16th day without any postoperative complications and is currently alive 6 months postoperatively without recurrence.
Subject(s)
Lymphadenopathy , Rectal Neoplasms , Robotic Surgical Procedures , Female , Humans , Neoadjuvant Therapy , Lymph Nodes/pathology , Lymph Node Excision , Rectal Neoplasms/surgery , Retrospective StudiesABSTRACT
We report a case of 72s male with locally advanced sigmoid colon cancer. Colonoscopy revealed an advanced sigmoid colon cancer(AV 15 cm, type 2, semi-peripheral, deeper than T3). He was diagnosed as cT4bN2M0, cStage â ¢c(Japanese Classification of Colorectal, appendiceal, and, Carcinoma, 9th edition), and was given chemotherapy as preoperative treatment. He was treated with CAPOX plus BEV as neoadjuvant chemotherapy. Preoperative diagnosis was ycT4bN0M0, ycStage â ¡c. The robot assisted high anterior resection and partial bladder resection were performed. The bladder was sutured under robotic assistance. The residual bladder capacity was 100 mL. Postoperative diagnosis was ypT0N0M0, ypStage 0, TRG 0 (AJCC). We experienced a case of neoadjuvant chemotherapy for rectosigmoid colon cancer with bladder invasion, which resulted in pCR.
Subject(s)
Robotics , Sigmoid Neoplasms , Humans , Male , Urinary Bladder/surgery , Neoadjuvant Therapy , Sigmoid Neoplasms/surgery , Fluorouracil , Antineoplastic Combined Chemotherapy Protocols/therapeutic useABSTRACT
74-year-old woman was diagnosed with locally advanced unresectable transverse colon cancer. She started CAPOX therapy as first-line therapy after ileostomy. After second course, MSI-high was detected, so nivolumab plus ipilimumab combination therapy was started as second-line therapy. After 4 courses of combination therapy, she was judged to be in partial response and surgery was performed. Histopathological diagnosis of the surgical specimen showed complete response, and she is still alive without recurrence 15 months after surgery.
Subject(s)
Colon, Transverse , Colonic Neoplasms , Female , Humans , Antineoplastic Combined Chemotherapy Protocols/therapeutic use , Colonic Neoplasms/drug therapy , Colonic Neoplasms/surgery , Ipilimumab , Nivolumab/therapeutic use , AgedABSTRACT
A 80s man was diagnosed circulated type 2 colon cancer at the transverse colon, and pathological findings was adenocarcinoma( por1). Genomic findings were microsatellite instability-high(MSI-H), all RAS wild type and BRAFV600E mutated. Contrast-enhanced CT showed an enlarged lymph nodes(#221, #222, #223, #214)along the middle colic and superior mesenteric artery. Clinical diagnosis was a locally advanced unresectable transverse colon cancer, cT4aN3M1a(LYM), cStage â £a. Drug therapy with pembrolizumab was prescribed. Six months later, contrast-enhanced CT and PET demonstrated remarkable shrinkage of the primary tumor and lymph nodes except 2 peri-colic enlarged lymph nodes. Primary lesion turned almost undetectable, however the biopsy demonstrated residual tumor. Two months later, CT showed that the residual lymph nodes had also disappeared.
Subject(s)
Colic , Colon, Transverse , Colonic Neoplasms , Humans , Male , Colic/pathology , Colon, Transverse/surgery , Colon, Transverse/pathology , Colonic Neoplasms/drug therapy , Colonic Neoplasms/surgery , Colonic Neoplasms/genetics , Lymph Nodes/pathology , Microsatellite Instability , Aged, 80 and overABSTRACT
A sixty-something man presented with lower abdominal pain in early Y month 20XX, and was examined at the hospital's internal medicine outpatient clinic. An abdominal CT showed a soft tissue mass around the left hip joint, and multiple enlarged lymph nodes from inside the pelvis to the mesentery of the abdomen. We noted a small-intestinal intussusception in the lower right abdomen, and suspected malignant lymphoma. We did a CT-guided biopsy on the left hip joint soft tissue mass, and performed surgery on the small-intestinal intussusception. During surgery, we noted an approximately 30 cm ileal intussusception located about 60 cm from the terminal ileum, and enlarged lymph nodes in the nearby mesentery. We removed the ileal intussusception. The pathological diagnosis was myeloid sarcoma, and the soft tissue mass in the left hip joint was also diagnosed as myeloid sarcoma. We performed a bone-marrow biopsy at the hematology department, and diagnosed acute myeloid leukemia M2. We then started remission-induction therapy and consolidation therapy, and the patient was diagnosed as in remission in Y+5 month 20XX. We also need to keep in mind myeloid sarcoma in the intestine as a subtype of acute myeloid leukemia, as malignant tumor in the small intestine presenting with intussusception.
Subject(s)
Intussusception , Sarcoma, Myeloid , Abdominal Pain , Humans , Intestine, Small , Intussusception/etiology , Intussusception/surgery , Male , Mesentery , Sarcoma, Myeloid/complications , Sarcoma, Myeloid/surgeryABSTRACT
A woman in her 70s with systemic sclerosis experienced dyspnea, and consequently, she was diagnosed with an esophago-pleural fistula, which was caused by a perforated esophageal ulcer. We administered conservative treatments including continuous pleural drainage and total parenteral nutrition. The fistula was closed but recurred, at which point we attempted to close the fistula by filling and shielding using polyglycolic acid (PGA) sheets and fibrin glue (FG). We were able to safely and smoothly fill and shield the fistula using the PGA sheets with a guidewire. We show that endoscopic closure of an esophago-pleural fistula using this technique is an effective, low-invasive treatment for gastrointestinal perforation and refractory fistulas.
Subject(s)
Fistula , Scleroderma, Systemic , Female , Fibrin Tissue Adhesive/therapeutic use , Humans , Polyglycolic Acid , Postoperative Complications , Scleroderma, Systemic/complications , UlcerABSTRACT
This study measures the acoustic power loss that occurs when an acoustic wave passes through a tube with an abrupt change in area. It is determined that the power loss is proportional to the third power of the velocity amplitude, and that the proportionality coefficient depends upon the area change ratio of the tube. On the other hand, the proportionality coefficient is almost independent of the acoustic impedance and frequency in the 80-250 Hz range. Furthermore, the effect of a tapered tube in reducing the coefficient is experimentally investigated. Based on these experimental results, an empirical estimation method for the acoustic power loss is proposed and validated using a high-pressure-helium-filled tube.
ABSTRACT
The immunoglobulin (Ig)-like cell adhesion molecule nectin-like molecule (Necl)-5/poliovirus receptor is up-regulated in many types of cancer cells and implicated in their abnormally enhanced cell proliferation and movement. We previously showed that Necl-5 cis-interacts with the platelet-derived growth factor (PDGF) receptor ß through the extracellular region and enhances its signaling. Although this cis-interaction does not affect the PDGF-induced tyrosine phosphorylation of the receptor, the interaction of the cytoplasmic region of Necl-5 with sprouty2 and the regulation of its activity are required for the enhancement of the PDGF receptor ß signaling by Necl-5. We investigated here the more detailed mechanism for this cis-interaction of Necl-5 with the PDGF receptor ß. Necl-5 contains three Ig-like domains and the PDGF receptor ß contains five Ig-like domains at their extracellular regions. We showed here that the third Ig-like domain of Necl-5 cis-interacted with the fifth Ig-like domain of the PDGF receptor ß. The recombinant protein of the third Ig-like domain of Necl-5 inhibited the cis-interaction of full-length Necl-5 with the PDGF receptor ß and the PDGF-induced activation of the ERK signaling pathway that was enhanced by Necl-5. These results revealed the novel roles of the third Ig-like domain of Necl-5 and the fifth Ig-like domain of the PDGF receptor ß in its signaling.
Subject(s)
Immunoglobulin Domains , Receptor, Platelet-Derived Growth Factor beta/metabolism , Receptors, Virus/metabolism , Animals , Binding, Competitive , HEK293 Cells , Humans , Mice , Mitogen-Activated Protein Kinase 1/genetics , Mitogen-Activated Protein Kinase 1/metabolism , Mitogen-Activated Protein Kinase 3/genetics , Mitogen-Activated Protein Kinase 3/metabolism , NIH 3T3 Cells , Phosphorylation , Protein Binding , Receptors, Virus/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Signal TransductionABSTRACT
The acoustic dissipation that occurs in a porous medium is experimentally investigated. Two conditions are tested. One is that the wall of the porous medium is wet by water, and the other is that it is dry. Experimental results show that water does not affect viscous dissipation; however, it affects the dissipation caused by pressure oscillation. Furthermore, it is found that the effect of water on the dissipation due to pressure oscillation increases with the temperature of the working gas. A theory that can consider the effect of condensation and evaporation on sound propagation is used to investigate the result. The theoretically and experimentally obtained values of dissipation are in good agreement. The reason for the effect of water is analyzed using the theory.
ABSTRACT
Metastatic umbilical tumors from internal malignancy, known as Sister Mary Joseph's Nodule(SMJN), are a relatively rare prognostic sign. An 86-year-old woman with pancreatic body carcinoma underwent distal pancreatectomy for D2 lymph node removal in 20XX. No peritoneal dissemination was found at that time. Postoperative chemotherapy was not administered due to her age. Eighteen months postoperatively, tumor marker values increased and chest computed tomography(CT) revealed a single mass in the left lung. We resected the suspected lung metastasis. Positron emission tomography-CT performed 23 months postoperatively for increased tumor marker values after resection showed a 18F-fluorodeoxyglucose accumulation ofapproximately 4 cm in the umbilicus. The diagnosis by biopsy was umbilical metastasis ofthe pancreatic cancer. No recurrence or other metastases were found, so we performed an umbilical tumor resection and abdominoplasty 24 months postoperatively. No peritoneal dissemination was found in her abdomen and the ascites cytology was negative. The tumor was in the subcutaneous tissue; thus, the possibility of infiltration from the primary site or peritoneal dissemination was low. The tumor marker values decreased after the resection. She was followed-up without postoperative anticancer chemotherapy. However, the tumor marker values increased again, so chemotherapy was initiated. We report a case ofresection of pancreatic cancer and operation for lung and umbilical metastases of pancreatic cancer.
Subject(s)
Lung Neoplasms , Pancreatic Neoplasms , Sister Mary Joseph's Nodule , Aged, 80 and over , Female , Humans , Lung Neoplasms/secondary , Lung Neoplasms/surgery , Neoplasm Recurrence, Local , Sister Mary Joseph's Nodule/secondary , Sister Mary Joseph's Nodule/surgery , UmbilicusABSTRACT
Cell-surface cytokine receptors are regulated by their cis-interacting stimulatory and inhibitory co-receptors. We previously showed that the Ig-like cell-adhesion molecule nectin-4 cis-interacts with the prolactin receptor through the extracellular region and stimulates prolactin-induced prolactin receptor activation and signaling, resulting in alveolar development in the mouse mammary gland. However, it remains unknown how this interaction stimulates these effects. We show here that the cis-interaction of the extracellular region of nectin-4 with the prolactin receptor was not sufficient for eliciting these effects and that the cytoplasmic region of nectin-4 was also required for this interaction. The cytoplasmic region of nectin-4 directly interacted with suppressor of cytokine signaling 1 (SOCS1), but not SOCS3, JAK2, or STAT5a, and inhibited the interaction of SOCS1 with JAK2, eventually resulting in the increased phosphorylation of STAT5a. The juxtamembrane region of nectin-4 interacted with the Src homology 2 domain of SOCS1. Both the interaction of nectin-4 with the extracellular region of the prolactin receptor and the interaction of SOCS1 with the cytoplasmic region of nectin-4 were required for the stimulatory effect of nectin-4 on the prolactin-induced prolactin receptor activation. The third Ig-like domain of nectin-4 and the second fibronectin type III domain of the prolactin receptor were involved in this cis-interaction, and both the extracellular and transmembrane regions of nectin-4 and the prolactin receptor were required for this direct interaction. These results indicate that nectin-4 serves as a stimulatory co-receptor for the prolactin receptor by regulating the feedback inhibition of SOCS1 in the JAK2-STAT5a signaling pathway.
Subject(s)
Cell Adhesion Molecules/metabolism , Janus Kinase 2/metabolism , Receptors, Prolactin/metabolism , STAT5 Transcription Factor/metabolism , Suppressor of Cytokine Signaling 1 Protein/metabolism , Animals , Cytoplasm/metabolism , Female , Fibronectins/metabolism , Gene Expression Regulation , HEK293 Cells , Humans , Mammary Glands, Animal/metabolism , Mice , Mutation , Phosphorylation , Prolactin/metabolism , Signal Transduction , Tumor Suppressor Proteins/metabolismABSTRACT
BACKGROUND: The prognostic impact of pancreatic ductal adenocarcinoma (PDAC) invasion to the splenic vessel is controversial. OBJECTIVE: The aim of this study was to assess the clinical value of pathological and radiological splenic vessel invasion in PDACs of the body and tail. METHODS: Medical records of patients with resectable PDAC of the body and tail who underwent distal pancreatectomy between 2003 and 2016 at the Kobe University Hospital were retrospectively analyzed. RESULTS: Overall, 68 patients (29 female and 39 male patients) were enrolled. Pathologically determined splenic vein invasion (p-SV) and splenic artery invasion (p-SA) were identified in 21 (30.9%) and 5 (7.4%) patients, respectively. The p-SV (but not p-SA) was an independent prognostic factor in multivariate analysis (p = 0.009). On analysis of recurrence patterns, patients with PDAC positive for p-SV were at a higher risk for liver metastasis (p = 0.022); however, the associations were not significant for other recurrence patterns. Liver metastasis occurred earlier in patients who were positive for p-SV (p = 0.015). Preoperative computed tomography effectively diagnosed pathological vessel invasion (SV: sensitivity, 95.2%, specificity, 72.3%; SA: sensitivity, 100%, specificity, 84.1%). Radiological SV invasion remained significant in multivariate analysis regarding postoperative survival (p = 0.007), and was also associated with early liver metastases (p = 0.008). CONCLUSIONS: Pathological/radiological SV invasion were independent adverse prognostic factors associated with early liver metastasis in patients with PDAC of the body/tail. Assessment of these findings may be useful in determining optimal therapeutic options in these patients.
Subject(s)
Adenocarcinoma/surgery , Carcinoma, Pancreatic Ductal/surgery , Liver Neoplasms/secondary , Pancreatectomy/mortality , Pancreatic Neoplasms/surgery , Splenic Vein/diagnostic imaging , Splenic Vein/pathology , Tomography, X-Ray Computed/methods , Adenocarcinoma/pathology , Aged , Carcinoma, Pancreatic Ductal/pathology , Female , Follow-Up Studies , Humans , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/surgery , Male , Neoplasm Invasiveness , Pancreatectomy/adverse effects , Pancreatic Neoplasms/pathology , Prognosis , Retrospective Studies , Survival Rate , Pancreatic NeoplasmsABSTRACT
PURPOSE: This study was designed to assess the potential role of the preoperative serum level of elastase 1 as a risk factor for recurrence in patients with resectable well-differentiated pancreatic neuroendocrine neoplasms (PanNETs). METHODS: Preoperative serum elastase 1 levels were measured in 53 patients with PanNETs who underwent complete tumor resection in two tertiary referral centers between January 2004 and June 2017. The preoperative elastase 1 levels were correlated with clinicopathological characteristics, including tumor recurrence and recurrence-free survival. RESULTS: The median elastase 1 level was 96 ng/dL (range: 21-990 ng/dL). Preoperative serum elastase 1 levels were significantly higher in those with tumors ≥ 20 mm in diameter (vs. < 20 mm, P = 0.018), WHO grade 2 (vs. grade 1, P = 0.035), and microscopic venous invasion (vs. without venous invasion, P = 0.039). The median preoperative serum level of elastase 1 was higher in patients with recurrence than in those without recurrence (251 vs. 80 ng/dL, P = 0.004). Receiver operating characteristic analysis of elastase 1 levels showed that a cutoff level of 250 ng/dL was associated with postoperative recurrence, with 63% sensitivity, 100% specificity, and 94% overall accuracy. Patients with higher elastase 1 levels showed significantly worse recurrence-free survival than that of those with lower levels (2-year recurrence-free survival rate: 25% and 92%, respectively, P < 0.001). CONCLUSIONS: Our data provide the first evidence that high preoperative elastase 1 levels may be a risk factor for postoperative recurrence in patients with resectable PanNETs.
Subject(s)
Biomarkers, Tumor/blood , Neoplasm Recurrence, Local/blood , Neuroendocrine Tumors/blood , Pancreatic Elastase/blood , Pancreatic Neoplasms/blood , Postoperative Complications , Adult , Aged , Aged, 80 and over , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neoplasm Recurrence, Local/enzymology , Neoplasm Recurrence, Local/pathology , Neoplasm Recurrence, Local/surgery , Neuroendocrine Tumors/enzymology , Neuroendocrine Tumors/pathology , Neuroendocrine Tumors/surgery , Pancreatic Neoplasms/enzymology , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/surgery , Prognosis , Retrospective Studies , Risk Factors , Survival RateABSTRACT
Mammary gland development is induced by the actions of various hormones to form a structure consisting of collecting ducts and milk-secreting alveoli, which comprise two types of epithelial cells known as luminal and basal cells. These cells adhere to each other by cell adhesion apparatuses whose roles in hormone-dependent mammary gland development remain largely unknown. Here we identified a novel cell adhesion apparatus at the boundary between the luminal and basal cells in addition to desmosomes. This apparatus was formed by the trans-interaction between the cell adhesion molecules nectin-4 and nectin-1, which were expressed in the luminal and basal cells, respectively. Nectin-4 of this apparatus further cis-interacted with the prolactin receptor in the luminal cells to enhance the prolactin-induced prolactin receptor signaling for alveolar development with lactogenic differentiation. Thus, a novel nectin-mediated cell adhesion apparatus regulates the prolactin receptor signaling for mammary gland development.
Subject(s)
Cell Adhesion Molecules/metabolism , Mammary Glands, Animal/growth & development , Receptors, Prolactin/metabolism , Signal Transduction , Animals , Cell Adhesion , Cell Adhesion Molecules/analysis , Cell Communication , Female , HEK293 Cells , Humans , Mammary Glands, Animal/metabolism , Mammary Glands, Animal/ultrastructure , Mice, Inbred C57BL , Nectins , Prolactin/metabolismABSTRACT
BACKGROUND AND AIM: The significance of examination time of esophagogastroduodenoscopy (EGD) for asymptomatic examinees is yet to be established. We aimed to clarify whether endoscopists who allot more examination time can detect higher numbers of neoplastic lesions among asymptomatic examinees. METHODS: We reviewed a database of consecutive examinees who underwent EGD in our hospital from April 2010 to September 2015. Staff endoscopists were classified into fast, moderate, and slow groups based on the mean examination time of EGD without a biopsy. Neoplastic lesion detection rate among these groups was compared using multiple logistic regression. RESULTS: Of the 55 786 consecutive examinees who underwent EGD, 15 763 asymptomatic examinees who were screened by staff doctors were analyzed. Mean examination time of 13 661 EGD without biopsy was 6.2 min (range, 2-18 min). When cut-off times of 5 and 7 min were used, four endoscopists were classified into the fast (mean duration, 4.4 ± 1.0 min), 12 into the moderate (6.1 ± 1.4 min), and four into the slow (7.8 ± 1.9 min) groups. Neoplastic lesion detection rates in the fast, moderate, and slow groups were 0.57% (13/2288), 0.97% (99/10 180), and 0.94% (31/3295), respectively. Compared with that in the fast group, odds ratios for the neoplastic lesion detection rate in the moderate and slow groups were 1.90 (95% confidence interval [CI], 1.06-3.40) and 1.89 (95% CI, 0.98-3.64), respectively. CONCLUSION: Endoscopists who do not allot adequate examination time may overlook neoplastic lesions in the upper gastrointestinal tract.