Estimating postsurgical outcomes of patients with a single hepatocellular carcinoma using gadoxetic acid-enhanced MRI: risk scoring system development and validation.

OBJECTIVES: To develop and validate risk scoring systems using gadoxetic acid-enhanced liver MRI features and clinical factors that predict recurrence-free survival (RFS) of a single hepatocellular carcinoma (HCC). METHODS: Consecutive 295 patients with treatment-naïve single HCC who underwent curative surgery were retrospectively enrolled from two centers. Cox proportional hazard models developed risk scoring systems whose discriminatory powers were validated using external data and compared to the Barcelona Clinic Liver Cancer (BCLC) or American Joint Committee on Cancer (AJCC) staging systems using Harrell's C-index. RESULTS: Independent variables-tumor size (per cm; hazard ratio [HR], 1.07; 95% confidence interval [CI]: 1.02-1.13; p = 0.005), targetoid appearance (HR, 1.74; 95% CI: 1.07-2.83; p = 0.025), radiologic tumor in vein or tumor vascular invasion (HR, 2.59; 95% CI: 1.69-3.97; p < 0.001), the presence of a nonhypervascular hypointense nodule on the hepatobiliary phase (HR, 4.65; 95% CI: 3.03-7.14; p < 0.001), and pathologic macrovascular invasion (HR, 2.60; 95% CI: 1.51-4.48; p = 0.001)-with tumor markers (AFP ≥ 206 ng/mL or PIVKA-II ≥ 419 mAU/mL) derived pre- and postoperative risk scoring systems. The risk scores showed comparably good discriminatory powers in the validation set (C-index, 0.75-0.82) and outperformed the BCLC (C-index, 0.61) and AJCC staging systems (C-index, 0.58; ps < 0.05). The preoperative scoring system stratified the patients into low-, intermediate-, and high-risk for recurrence, whose 2-year recurrence rate was 3.3%, 31.8%, and 85.7%, respectively. CONCLUSION: The developed and validated pre- and postoperative risk scoring systems can estimate RFS after surgery for a single HCC. KEY POINTS: • The risk scoring systems predicted RFS better than the BCLC and AJCC staging systems (C-index, 0.75-0.82 vs. 0.58-0.61; ps < 0.05). • Five variables-tumor size, targetoid appearance, radiologic tumor in vein or vascular invasion, the presence of a nonhypervascular hypointense nodule on the hepatobiliary phase, and pathologic macrovascular invasion-combined with tumor markers derived risk scoring systems predicting postsurgical RFS for a single HCC. • In the risk scoring system using preoperatively-available factors, patients were classified into three distinct risk groups, with 2-year recurrence rates in the low-, intermediate-, and high-risk groups being 3.3%, 31.8%, and 85.7% in the validation set.

Laparoscopic cholecystectomy in patients with previous upper midline abdominal surgery: comparison of laparoscopic cholecystectomy after gastric surgery and non-gastric surgery using propensity score matching.

BACKGROUND: Previous upper midline abdominal surgery is a reported relative contraindication to laparoscopic cholecystectomy. We aimed to investigate the effects of previous upper abdominal surgery on the feasibility and safety of laparoscopic cholecystectomy; we evaluated the effects of the previous upper abdominal surgery type on laparoscopic cholecystectomy with respect to complications and conversion to open surgery. METHODS: We prospectively evaluated 1,258 patients who underwent laparoscopic cholecystectomy, including those who underwent upper midline abdominal surgery previously, at a single tertiary referral center. The perioperative and postoperative outcomes-open conversion rate, operation time, intraoperative and postoperative complications, and length of hospital stay-were evaluated. Patients were grouped according to the previous surgical method into the gastric (n = 77), non-gastric (n = 40), and control (n = 1141) groups. Patients in the gastric + non-gastric groups (n = 117) were 1:1 matched with those in the control group (n = 117) using propensity score matching (PSM). RESULTS: Before PSM, age, sex, open conversion rate, gallbladder status, port number, overall morbidity, and postoperative hospital stay duration did not significantly differ between the gastric and non-gastric groups; the body mass index (22.3 ± 3.4 versus 24.1 ± 3.8 kg/m2, p = 0.009) and operation time (129.9 ± 63.6 versus 97.9 ± 51.1 min, p = 0.004) significantly differed. After PSM, age, sex, body mass index, and American Society of Anesthesiology score did not significantly differ between gastric + non-gastric (n = 117) and conventional groups (n = 117; the operation time (118.9 ± 61.3 versus 75.8 ± 37.1 min, p < 0.001), open conversion rate (n = 6, 5.1% versus n = 0, 0.0%, p = 0.013), port number, overall morbidities (n = 26, 22.2% versus n = 10, 8.5%, p = 0.004), and postoperative hospital stay duration (6.7 ± 4.3 versus 5.5 ± 3.2 days, p = 0.031) significantly differed. CONCLUSION: Previous upper midline abdominal surgery was not contraindicative to safe laparoscopic cholecystectomy. Patients with previous upper midline abdominal surgery undergoing laparoscopic cholecystectomy should be informed preoperatively of the probability of conversion to open surgery, lengthened duration, and associated morbidities.

Acute Toxicity Evaluation of the Disinfectant Containing Percarbonate and Tetraacetylethylenediamine by Measuring Behavioral Responses of Small Fish Using Image Analysis.

Disinfectants containing percarbonate and tetraacetylethylenediamine (TAED) has been developed as an effective and relatively safe disinfectant to destroy viruses and bacteria in animals and humans, however it is known that most disinfectants can cause danger to living organisms including humans. In the current study, acute toxicity of the disinfectant composed of percarbonate and TAED was assessed by measuring behavioral responses as well as lethal concentrations of aquatic organisms such as medaka and zebrafish when they were exposed to it. First, the breeding water properties were determined by measuring dissolved oxygen (DO) and pH changes over time up to 96 h in acute toxicity tests using the medaka, and the lethal concentration 50% (LC50, 88.39 ppm) was calculated using the lethality rate of the fish. This experiment was conducted in compliance with traditional OECD guidelines. Second, the assessment of behavioral responses (locomotive activity and swimming speed) with the zebrafish were assessed by the image analysis to capture the images per second for three hours, and the collected data were processed using image analysis to calculate the locomotive activity and swimming speed. Finally, the LC50 (135.76 ppm) of the disinfectant to the fish was also measured after three hours. Overall, the data revealed that LC50 of the disinfectant may be affected by the pH of the water exposed to the disinfectant, not by the DO in the water. In addition, the results from the image analysis indicated that the behavioral responses of the fish can further assess the acute toxicity of the disinfectant at concentrations below the LC50 and there was a relationship (R2 = 0.85) between the behavioral responses and the survival rate of the fish. Electronic Supplementary Material ESM: The online version of this article (doi: 10.1007/s12257-021-0419-0) contains supplementary material, which is available to authorized users.

Acute cholecystitis: predictive clinico-radiological assessment for conversion of laparoscopic cholecystectomy.

BACKGROUND: Previous studies evaluating predictive factors for the conversion from laparoscopic to open cholecystectomy have reported conflicting conclusions. PURPOSE: To create a risk assessment model to predict the conversion from laparoscopic to open cholecystectomy in patients with acute calculous cholecystitis. MATERIAL AND METHODS: A retrospective review of patients with acute calculous cholecystitis with available preoperative contrast-enhanced computed tomography (CT) findings who underwent laparoscopic cholecystectomy was performed. Forty-four parameters-including demographics, clinical history, laboratory data, and CT findings-were analyzed. RESULTS: Among the included 581 patients, conversion occurred in 113 (19%) cases. Multivariate analysis identified obesity (odd ratio [OR] 2.58, P = 0.04), history of abdominal surgery (OR 1.78, P = 0.03), and prolonged prothrombin time (OR 1.98, P = 0.03) as predictors of conversion. In preoperative CT findings, the absence of gallbladder wall enhancement (OR 3.15, P = 0.03), presence of a gallstone in the gallbladder infundibulum (OR 2.11, P = 0.04), and inflammation of the hepatic pedicle (OR 1.71, P = 0.04) were associated with conversion. Inter-observer agreement for CT study interpretation was very good (range 0.81-1.00). A model was created to calculate the risk for conversion, with an area under the receiver operating characteristic curve of 0.87. The risk for conversion, estimated based on the number of factors identified, was in the range of 5.3% (with one factor) to 86.4% (with six factors). CONCLUSION: Obesity, history of abdominal surgery, prolonged prothrombin time, absence of gallbladder wall enhancement, presence of a gallstone in the gallbladder infundibulum, and inflammation of the hepatic pedicle are associated with conversion of laparoscopic to open cholecystectomy.

Risk Factors for Recurrence of Right Colonic Diverticulitis.

BACKGROUND: Right colonic diverticulitis (RCD) is more common in Asian countries than in Western countries, and the risk factors for recurrence of RCD are not fully understood. The objective of this study was to assess the risk factors for recurrence of RCD. METHODS: We analyzed 296 patients admitted for treatment of RCD in the Gachon University Gil Medical Center from December 2001 to October 2014. Gender, age, BMI, obesity, hypertension, diabetes mellitus, alcohol consumption, smoking, Hinchey classification, and hospital stay were investigated as risk factors for recurrence. RESULTS: Of the 296 patients with RCD, 31 patients recurred after conservative treatment. The median time interval between the initial episode and recurrence of diverticulitis was 10.4 months. In the univariate analysis, a high recurrence rate was observed in patients with a history of alcohol consumption, smoking, and long hospital stay. In the multivariate analysis, the recurrence rate was much higher (p < 0.001) in patients who stayed in the hospital for more than 10 days after the first attack. Smoking also elevated the recurrence rate (p = 0.011). CONCLUSION: Factors associated with recurrence of RCD may include smoking and the long hospital stay due to complexity when first diverticulitis occurs. Further prospective large-scale studies are needed to draw a definite conclusion.

The efficacy of real-time colour Doppler flow imaging on endoscopic ultrasonography for differential diagnosis between neoplastic and non-neoplastic gallbladder polyps.

OBJECTIVES: We evaluated the usefulness of real-time colour Doppler flow (CDF) endoscopic ultrasonography (EUS) for differentiating neoplastic gallbladder (GB) polyps from non-neoplastic polyps. METHODS: Between August 2014 and December 2016, a total of 233 patients with GB polyps who underwent real-time CDF-EUS were consecutively enrolled in this prospective study. CDF imaging was subjectively categorized for each patient as: strong CDF pattern, weak CDF pattern and no CDF pattern. RESULTS: Of the 233 patients, 115 underwent surgical resection. Of these, there were 90 cases of non-neoplastic GB polyps and 23 cases of neoplastic GB polyps. In a multivariate analysis, a strong CDF pattern was the most significant predictive factor for neoplastic polyps; sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 52.2 %, 79.4 %, 38.7 %, 86.9 % and 73.9 %, respectively. Solitary polyp and polyp size were associated with an increased risk of neoplasm. CONCLUSIONS: The presence of a strong CDF pattern as well as solitary and larger polyps on EUS may be predictive of neoplastic GB polyps. As real-time CDF-EUS poses no danger to the patient and requires no additional equipment, it is likely to become a supplemental tool for the differential diagnosis of GB polyps. KEY POINTS: • Differential diagnosis between neoplastic polyps and non-neoplastic polyps of GB is limited. • The use of real-time CDF-EUS was convenient, with high agreement between operators. • The real-time CDF-EUS is helpful in differential diagnosis of GB polyps.

Pancreatic volume and endocrine function changes following pancreaticoduodenectomy for peri-ampullary neoplasms: A retrospective single-center study utilizing pancreas volumetry.

Backgrounds/Aims: We evaluated long-term pancreatic functional outcomes, including pancreatic volumetry after pancreaticoduodenectomy (PD) for peri-ampullary neoplasm. Methods: We retrospectively reviewed 353 patients with a 12-month follow-up who underwent elective pancreaticoduodenectomies for peri-ampullary neoplasms at a single university hospital between January 2011 and December 2020. Perioperative and postoperative outcomes, long-term pancreatic endocrine functions, and pancreatic volume changes 12 month postoperatively were evaluated. Results: The mean age was 65.4 years, and the sex ratio was 1.38. The patients with prediagnosed diabetes mellitus (DM) comprised 31.4%. The peri-ampullary neoplasm origins were: the pancreas (49.0%), common bile duct (27.2%), ampulla of Vater (18.4%), and duodenum (5.4%). The 1-week, and 3-, 6-, and 12-month postoperative proportions of patients with DM diagnosed before surgery combined with new-onset postoperative DM were 39.7%, 42.8%, 43.9%, and 49.6%, respectively. The preoperative and postoperative 1-week, and 3-, 6-, and 12-month mean pancreatic volumes were 82.3, 38.7, 28.1, 24.9, and 25.5 mL, respectively. Univariate risk factor analyses for new-onset DM after PD observed no significant difference between the 'No DM after PD' and 'New-onset DM after PD' groups. Conclusions: Following PD for peri-ampullary neoplasms, pancreatic endocrine functions and volumes continued to decrease for a minimum of 12 months. The current study did not identify any causal relationship between pancreatic endocrine dysfunction and pancreatic atrophy following PD.

Single-port laparoscopic appendectomy versus conventional laparoscopic appendectomy: a prospective randomized controlled study.

OBJECTIVE: To compare surgical outcomes and quality of life between single-port laparoscopic appendectomy (SPLA) and conventional laparoscopic appendectomy (CLA) in patients with acute appendicitis. BACKGROUND: A prospective randomized single center study was performed to compare the outcome of SPLA and CLA in patients with acute appendicitis. METHODS: A total of 248 patients were randomized, but because of 18 withdrawals, the outcome of 224 is analyzed, 116 in CLA and 114 in SPLA. RESULTS: There was no significant difference in the overall complication rate (P = 0.470). There were no significant differences in infectious complications between the SPLA group and the CLA group (10.2% and 12.4%, respectively). The wound complication rate between the 2 groups was not significant (5.1% and 10.6%, respectively; P = 0.207). Cosmetic satisfaction score, 36-item short-form health survey, and postoperative pain scores were not significantly different between 2 groups. CONCLUSIONS: SPLA failed to show any advantages over CLA relative to pain and cosmesis. However, SPLA is as safe as CLA (RCT number 01348464).

The Impact of the Multiple Bile Ducts on Postoperative Biliary Complications In Patients Undergoing Living Donor Liver Transplantation.

BACKGROUND: We aimed to investigate the correlation between bile duct number and biliary complications in patients who underwent donor liver transplantation (LDLT). METHODS: We reviewed all patients who underwent LDLT in our hospital between July 2008 and December 2020. The patients were divided into 2 groups according to the number of bile ducts in the living donor graft (single duct [SD] or multiple ducts [MD]). Collected data included donor and recipient demographics, surgical data including bile duct reconstruction, and perioperative and postoperative outcomes. No prisoners were used in this study, and participants were neither coerced nor paid. The current study complies with the Helsinki Congress and the Declaration of Istanbul. RESULTS: All 70 patients were classified as SD (n = 48) and MD (n = 22). Complications related to the bile duct occurred in 27 (38.6%) patients and were more common in the MD group (54.5% vs 31.3%; odds ratio, 2.4). The MD patients had a longer operation time (1052 ± 251 vs 910 ± 215 minutes, P = .019) and a higher percentage of hepaticojejunostomy (31.8% vs 8.3%, P = .012). Donor age, graft-recipient weight ratio, cold ischemic time, and transfusion volume did not differ between groups. Twenty-one patients (77.7%) fully recovered from complications related to the bile duct, but 3 patients (4.3%) had liver graft failure. CONCLUSION: Bile duct-related complications were common in LDLT patients, despite overall good results. Multiple bile ducts may be a potent risk factor for postoperative biliary complications.

Pancreatic Tumor-Targeting Stemsome Therapeutics.

Owing to the intrinsic ability of stem cells to target the tumor environment, stem-cell-membrane-functionalized nanocarriers can target and load active anticancer drugs. In this work, a strategy that focuses on stem cells that self-target pancreatic cancer cells is developed. In particular, malignant deep tumors such as pancreatic cancer cells, one of the intractable tumors that currently have no successful clinical strategy, are available for targeting and destruction. By gaining the targeting ability of stem cells against pancreatic tumor cells, stem cell membranes can encapsulate nano-polylactide-co-glycolide loaded with doxorubicin to target and reduce deep pancreatic tumor tissues. Considering the lack of known target proteins on pancreatic tumor cells, the suggested platform technology can be utilized for targeting any malignant tumors in which surface target receptors are unavailable.

Automated pancreas segmentation and volumetry using deep neural network on computed tomography.

Pancreas segmentation is necessary for observing lesions, analyzing anatomical structures, and predicting patient prognosis. Therefore, various studies have designed segmentation models based on convolutional neural networks for pancreas segmentation. However, the deep learning approach is limited by a lack of data, and studies conducted on a large computed tomography dataset are scarce. Therefore, this study aims to perform deep-learning-based semantic segmentation on 1006 participants and evaluate the automatic segmentation performance of the pancreas via four individual three-dimensional segmentation networks. In this study, we performed internal validation with 1,006 patients and external validation using the cancer imaging archive pancreas dataset. We obtained mean precision, recall, and dice similarity coefficients of 0.869, 0.842, and 0.842, respectively, for internal validation via a relevant approach among the four deep learning networks. Using the external dataset, the deep learning network achieved mean precision, recall, and dice similarity coefficients of 0.779, 0.749, and 0.735, respectively. We expect that generalized deep-learning-based systems can assist clinical decisions by providing accurate pancreatic segmentation and quantitative information of the pancreas for abdominal computed tomography.

Antithymocyte globulin versus basiliximab induction for kidney transplantation in elderly patients: matched analysis within the Korean multicentric registry.

BACKGROUND: Basiliximab (BSX) and antithymocyte globulins (ATGs), are two major immunosuppressive agents commonly used as induction therapy for kidney transplant (KT) recipients. The superiority of ATG over BSX has not been well established, especially in elderly KT recipients with low immunological risk. METHODS: A total of 847 elderly (≥60 years old), low-risk KT patients in the Korean Organ Transplantation Registry were propensity score-matched at a 1:2 ratio and compared according to ATG or BSX induction therapy. The primary outcome was patient and graft survival and biopsy-proven acute cellular rejection. The secondary outcome was graft function, BK virus nephropathy, infection, cancer, new-onset diabetes mellitus after transplantation (NODAT), and delayed graft function. RESULTS: In total, 165 patients in the ATG group were matched with 298 patients in the BSX group with average ages of 64.3 and 64.2 years, respectively. During a follow-up of 28.5 ± 10.4 months, the cumulative probabilities of death-censored graft failure at 3 years posttransplantation were 1.3% and 1.4% in ATG and BSX groups, respectively, without a significant difference (p = 0.72). The cumulative probability of NODAT at 3 years posttransplantation was significantly higher in the BSX group (35.6% vs. 21.6%, p = 0.02). The median tacrolimus trough level was significantly lower at 6 months after KT in the ATG group (5.7 ng/mL vs. 6.4 ng/mL, p = 0.001). There were no differences in the other evaluated outcomes. CONCLUSION: Compared with BSX, in elderly, low-risk KT patients, ATG reduced tacrolimus and steroid requirements without differences in all-cause mortality, rejection, or infection, resulting in a reduced NODAT incidence.

Chronic kidney disease in cancer patients: an independent predictor of cancer-specific mortality.

BACKGROUND/AIMS: The effects of chronic kidney disease (CKD) on the risk of death for patients with malignant disease are uncertain. The aim of this study was to determine the association between the presence of CKD and mortality in cancer patients. METHOD: We retrospectively reviewed the cases of 8,223 cancer patients with one or more serum creatinine measurements from January 1, 2000 to December 31, 2004. The key outcome was cancer-specific mortality within the follow-up period. The cumulative incidence rate for death from cancer was estimated using methods of competing risks survival analysis. Cox proportional-hazards regression with the use of Fine and Gray's proportional-hazards model were evaluated in multiple analyses. RESULTS: CKD was associated with an increased risk of death in cancer patients. The adjusted hazard ratios were 1.12 for patients with an estimated glomerular filtration rate (eGFR) of 30-59 ml/min/1.73 m(2) (95% confidence interval 1.01-1.26, p = 0.04) and 1.75 for patients with an eGFR <30 ml/min/1.73 m(2) (95% confidence interval 1.32-2.32, p < 0.001). CONCLUSIONS: CKD should be considered a risk factor for survival among patients with cancer.

A retrospective clinicopathological analysis of appendiceal tumors from 3,744 appendectomies: a single-institution study.

PURPOSE: This study was conducted to describe the clinicopathological characteristics of appendiceal tumors and to evaluate their appropriate management. METHODS: Between September 2000 and September 2005, 28 appendiceal tumors were identified by a retrospective review of 3,744 appendectomies. RESULTS: Twenty-eight patients were found to have appendiceal tumors (incidence, 0.7%).The largest single group of tumors were benign mucinous cystadenomas (50%); carcinoids (32.1%) were next, and they were followed by malignant tumors (17.9%). Four out of five patients who had malignant appendiceal tumors presented with periappendiceal abscess. None of the patients was correctly diagnosed preoperatively. One-stage curative resection was possible in more than 76% of the patients, and the rate of making the correct preoperative diagnosis was 35%. CONCLUSION: Most appendiceal tumors presented with appendicitis and periappendiceal abscess. Appendiceal tumors should be included in the differential diagnosis when an unexpected appendiceal mass is encountered during appendectomy.

Long-term surgical outcomes in patients with hepatocellular carcinoma undergoing laparoscopic vs. open liver resection: A retrospective and propensity score-matched study.

BACKGROUND/OBJECTIVES: There is limited availability of well-designed comparative studies using propensity score matching with a sufficient sample size to compare laparoscopic liver resection (LLR) vs. open liver resection (OLR) for hepatocellular carcinoma (HCC). We aimed to compare the feasibility and safety of LLR and OLR in patients with HCC. METHODS: We enrolled 168 patients who underwent elective LLR (n = 58) or OLR (n = 110) for HCC in two tertiary medical centers between November 2009 and December 2018. Patients who underwent LLR were propensity score-matched to patients who underwent OLR in a 1:1 ratio. Perioperative and postoperative outcomes and disease-free and overall survival rates were prospectively evaluated. RESULTS: Among the 116 patients analyzed, 58 each belonged to the LLR and OLR groups. We performed 85 segmentectomies or sectionectomies, 19 left-lateral-sectionectomies, 9 left-hemihepatectomies, and 3 right-hemihepatectomies. There was no significant difference in age, sex, Child-Pugh class, original liver disease, preoperative alpha-fetoprotein, tumor size, tumor location, overall morbidity, and operative time. There was a significant difference in the length of postoperative hospital stay between the two groups (LLR vs OLR; 8 vs 10 days, p = 0.003). The 1-, 3-, and 5-year overall survival rates in the LLR and OLR groups were 96.6%, 92.8%, and 73.3% and 93.1%, 88.8%, and 76.1%, respectively (p = 0.642). The 1-, 3-, and 5-year disease-free survival rates in the LLR and OLR groups were 84.4%, 64.0%, and 60.2% and 93.1%, 67.4%, and 63.9%, respectively (p = 0.391). CONCLUSION: LLR for HCC can be performed safely with acceptable short-term and long-term outcomes compared with OLR.

The impact of Model for End-Stage Liver Disease score on deceased donor liver transplant outcomes in low volume liver transplantation center: a retrospective and single-center study.

PURPOSE: In June 2016, the Model for End-Stage Liver Disease (MELD) score was employed in South Korea instead of the Child-Turcotte-Pugh (CTP) score. This study compared the outcomes of deceased donor liver transplantation (DDLT) before and after the MELD system application. METHODS: This retrospective study reviewed 48 patients who underwent DDLT for end-stage liver disease at a single tertiary referral center between January 2014 and December 2018. The patients were categorized into the pre-MELD (22 patients) and post-MELD (26 patients) groups. The demographics, postoperative outcomes, and overall survival time were evaluated between the 2 groups. RESULTS: The 2 groups had no differences in age, sex, ABO type, etiology for liver transplantation, CTP-score, operation time, cold ischemic time, and amount of red blood cell transfusion, although their MELD score differed significantly (post-MELD group, 36.2 ± 4.9; pre-MELD group, 27.7 ± 11.8; P < 0.001). The post-MELD group has longer intensive care unit stay (11.2 ± 9.5 days vs. 5.7 ± 4.5 days, P = 0.018) and hospital stay than the pre-MELD group (36.8 ± 26 days vs. 22.8 ± 9.3 days, P = 0.016). The 1-year survival rate was lower in the post-MELD group (61.5% vs. 86.4%, P = 0.029). CONCLUSION: After MELD allocation, patients with high MELD scores had increased DDLT and consequently required a longer recovery time, which could negatively affect survival. According to the experience of a small-volume center, these problems were related to both severe organ shortages in South Korea and MELD allocation.

Modeling the Effects of Elevated Temperature and Weed Interference on Rice Grain Yield.

A 3-year phytotron study was conducted in Suwon (37.27°N, 126.99°E), Korea, to evaluate and model the effects of elevated temperature on rice-weed competition. The dry weight and the number of panicles in rice were the most susceptible components to weed interference during the early growth of rice, regardless of weed species, while other yield components, including the number of grains, % ripened grain, and 1000-grain weight, were more susceptible to elevated temperature. A rectangular hyperbolic model well demonstrated that rice grain yield was affected by weed interference under elevated temperature, showing that the competitiveness of late watergrass (Echinochloa oryzicola) and water chestnut (Eleocharis kuroguwai) increased under elevated temperature conditions. Quadratic and linear models well described the effects of elevated temperature on the weed-free rice grain yield and weed competitiveness values of the rectangular hyperbolic model for the two weed species, respectively. Thus, a combined rectangular hyperbolic model incorporated with the quadratic and linear models well demonstrated the effects of elevated temperature and weed interference on rice grain yield across years. Using the combined model and estimated parameters, the rice grain yields were estimated to be 58.9, 48.5, 41.3, and 35.9% of the yields under weed-free conditions for 80 plants m-2 of late watergrass and 86.8, 64.3, 51.1, and 42.3% of the yields under weed-free conditions for 80 plants m-2 of water chestnut at 1,300, 1,500, 1,700, and 1,900°C·days of accumulated growing degree days (GDD; from transplanting to flowering, 89 days), respectively. The combined model developed in this study can provide an empirical description of both the elevated temperature and weed interference effects on rice yield and can be used for predicting rice grain yields due to weed interference under future elevated temperature conditions.

Early vascular access blood flow as a predictor of long-term vascular access patency in incident hemodialysis patients.

The long-term clinical benefits of vascular access blood flow (VABF) measurements in hemodialysis (HD) patients have been controversial. We evaluated whether early VABF may predict long-term vascular access (VA) patency in incident HD patients. We enrolled 57 patients, of whom 27 were starting HD with arteriovenous fistulas (AVFs) and 30 with arteriovenous grafts (AVGs). The patients' VABF was measured monthly with the ultrasound dilution technique over the course of the first six months after the VA operation. During the 20.4-month observational period, a total of 40 VA events in 23 patients were documented. The new VA events included 13 cases of stenosis and 10 thrombotic events. The lowest quartile of average early VABF was related to the new VA events. After adjusting for covariates such as gender, age, hypertension, diabetes, VA type, hemoglobin levels, body mass index, parathyroid hormone, and calcium-phosphorus product levels, the hazard ratio of VABF (defined as <853 mL/min in AVF or <830 mL/min in AVG) to incident VA was 3.077 (95% confidence interval, 1.127-8.395; P=0.028). There were no significant relationships between early VABF parameters and VA thrombosis. It is concluded that early VABF may predict long-term VA patency, particularly VA stenosis.

Single Orifice Outflow Reconstruction in Various Tributaries of the Right Liver Graft Using Commercialized Polyethylene Terephthalate Y-graft: A technical Simplification of Venous Reconstruction in 3 Cases.

BACKGROUND: Hepatic vein reconstruction is very important in living donor liver transplantation to prevent outflow obstruction and maintain the graft function. In right liver grafts, reconstruction of the tributary of the middle hepatic vein (MHV) or inferior hepatic vein (IHV) is mandatory, and several options are recommended. Recently, it has been reported that a single, wide orifice is an important perquisite for adequate outflow in liver transplantation. This can be achieved by various venoplasty techniques in back table procedures using the recipient's saphenous vein, a cryopreserved vascular graft, or a synthetic vascular graft. METHODS: Due to the insufficiency of an actual graft, we used a simple back table technique with the polyethylene terephthalate Y-graft in 3 cases of right liver grafting between October 2015 and September 2019 in Gil Medical Center. We used both arms of the Y-graft for anastomosis of the 2 largest branches of both tributaries. The main trunk of the Y-graft was then joined to the right hepatic vein (RHV). We analyzed these patients' outcomes retrospectively and the study was approved by institutional review board in Gachon University Gil Medical Center. This study strictly complies with the Helsinki Congress and the Istanbul Declaration regarding donor source and informed consent was obtained from all patients. RESULTS: All 3 patients had good tributary patency and allograft function at discharge. The patency of the graft was maintained over a period ranging from 2 months to 2 years, without any anticoagulant administration. Regardless of the tributary patency, all patients survived with good outflow of the grafts. CONCLUSIONS: Although we had little prior experience in synthetic venous grafts, these cases indicate some interesting findings, with a simple and intuitive procedure. We believe our technique is a practical method for manipulating various venous tributaries in a right liver graft.