Unraveling the impact of cancer-associated fibroblasts on hypovascular pancreatic neuroendocrine tumors.

BACKGROUND: Pancreatic neuroendocrine tumors (PNETs) with low microvessel density and fibrosis often exhibit clinical aggressiveness. Given the contribution of cancer-associated fibroblasts (CAFs) to the hypovascular fibrotic stroma in pancreatic ductal adenocarcinoma, investigating whether CAFs play a similar role in PNETs becomes imperative. In this study, we investigated the involvement of CAFs in PNETs and their effects on clinical outcomes. METHODS: We examined 79 clinical PNET specimens to evaluate the number and spatial distribution of α-smooth muscle actin (SMA)-positive cells, which are indicative of CAFs. Then, the findings were correlated with clinical outcomes. In vitro and in vivo experiments were conducted to assess the effects of CAFs (isolated from clinical specimens) on PNET metastasis and growth. Additionally, the role of the stromal-cell-derived factor 1 (SDF1)-AGR2 axis in mediating communication between CAFs and PNET cells was investigated. RESULTS: αSMA-positive and platelet-derived growth factor-α-positive CAFs were detected in the hypovascular stroma of PNET specimens. A higher abundance of α-SMA-positive CAFs within the PNET stroma was significantly associated with a higher level of clinical aggressiveness. Notably, conditioned medium from PNET cells induced an inflammatory phenotype in isolated CAFs. These CAFs promoted PNET growth and metastasis. Mechanistically, PNET cells secreted interleukin-1, which induced the secretion of SDF1 from CAFs. This cascade subsequently elevated AGR2 expression in PNETs, thereby promoting tumor growth and metastasis. The downregulation of AGR2 in PNET cells effectively suppressed the CAF-mediated promotion of PNET growth and metastasis. CONCLUSION: CAFs drive the growth and metastasis of aggressive PNETs. The CXCR4-SDF1 axis may be a target for antistromal therapy in the treatment of PNET. This study clarifies mechanisms underlying PNET aggressiveness and may guide future therapeutic interventions targeting the tumor microenvironment.

Novel Non-duct-to-Mucosa Pancreaticojejunostomy Reconstruction After Pancreaticoduodenectomy: Focus on the Occurrence of Post-pancreatectomy Hemorrhage and Intra-abdominal Abscess.

BACKGROUND: Postoperative pancreatic fistulas (POPFs) are considered inevitable in some patients after pancreaticoduodenectomy (PD), and measures to minimize their clinical impact are needed. Postpancreatectomy hemorrhage (PPH) and intra-abdominal abscess (IAA) are the most severe POPF-related complications, and concomitant leakage of contaminated intestinal content is considered the main cause. An innovative method, modified non-duct-to-mucosa pancreaticojejunostomy (TPJ), was created to prevent concomitant leakage of intestinal content, and its effectiveness was compared between two periods. METHODS: All PD patients undergoing pancreaticojejunostomy from 2012 to 2021 were included. The TPJ group consisted of 529 patients recruited from January 2018 to December 2021. A total of 535 patients receiving the conventional method (CPJ) from January 2012 to June 2017 were used as a control group. PPH and POPF were defined according to the International Study Group of Pancreatic Surgery definition, but only PPH grade C was included for analysis. An IAA was defined as a collection of postoperative fluid managed by CT-guided drainage with documental culture. RESULTS: There were no significant differences in the rate of POPF between the two groups (46.0% vs. 44.8%; p = 0.700). Furthermore, the percentages of bile in the drainage fluid in the TPJ and CPJ groups were 2.3% and 9.2%, respectively (p < 0.001). Lower proportions of PPH (0.9% vs. 6.5%; p < 0.001) and IAA (5.7% vs. 10.8%; p < 0.001) were observed for TPJ than for CPJ. On adjusted models, TPJ was significantly associated with a lower rate of PPH (odds ratio [OR] 0.132, 95% confidence interval [CI] 0.051-0.343; p < 0.001) and IAA (OR 0.514, 95% CI 0.349-0.758; p = 0.001) than CPJ. CONCLUSIONS: TPJ is feasible to be performed and is associated with a similar rate of POPF but a lower percentage of concomitant bile in the drainage fluid and subsequent rates of PPH and IAA than CPJ.

The effect of immediate lymphatic reconstruction on the post-operative drain output after axillary lymph node dissection for breast cancer: A retrospective comparative study.

INTRODUCTION: Axillary lymph node dissection (ALND) for breast cancer has been considered to be associated with a variety of complications, such as excessive postoperative wound drainage, prolonged drain placement, or seroma formation in the short term, or arm lymphedema in the long run. Immediate lymphedema reconstruction (ILR) has been proposed to reduce the occurrence of arm lymphedema by anastomosing the transected arm lymphatics to nearby branches of the axillary vein immediately after ALND. This study aims to demonstrate that ILR can also reduce the postoperative drainage amount. PATIENTS AND METHODS: Between April 2020 and January 2022, a total of 76 breast cancer patients receiving ALND were reviewed. Forty four of them also received ILR immediately after ALND. The assignment of ILR surgery was non-random, based on patients' willingness and plastic surgeons' availability. The lymphatic vessels in the axillary wound were anastomosed with nearby terminal branches of the axillary vein under surgical microscope. Patients' characteristics, including age, body mass index (BMI), neoadjuvant therapy, type of breast surgery, the occurrence of seroma formation, number of removed lymph nodes, number of positive nodes, and the drainage amount from the operative wounds were compared between ILR and non-ILR groups. RESULTS: No statistically significant difference was noted between groups in terms of age (56.5 ± 9.8 vs. 60.9 ± 10.7, p = .09), BMI (22.6 ± 3.7 vs. 23.7 ± 3.8, p = .27), type of breast surgery (p = .32), the occurrence of seroma formation (p = 1.0), the likelihood of receiving neoadjuvant therapy (p = .12), number of lymph nodes removed (17.5 ± 7.6 vs. 17.4 ± 8.3, p = .96), or number of positive nodes on final pathology (3.7 ± 5.4 vs. 4.8 ± 8.5, p = .53) except the ILR group had statistically significantly less drainage amount than non-ILR group (39.3 ± 2.6 vs. 48.3 ± 3.7, p = .046). CONCLUSION: For breast cancer patients receiving ALND, the immediate lymphatic reconstruction can reduce the postoperative drainage amount from the operative wound.

Distinct Survival Outcomes in Subgroups of Stage III Pancreatic Cancer Patients: Taiwan Cancer Registry and Surveillance, Epidemiology and End Results registry.

PURPOSE: Pancreatic cancer is one of the most malignant cancers with poor survival. The latest edition of the American Joint Committee on Cancer (AJCC) staging system classifies the majority of operable pancreatic cancer patients as stage-III, while dramatic heterogeneity is observed among these patients. Therefore, subgrouping is required to accurately predict their prognosis and define a treatment plan. This study conducts a cohort study to provide a more precise classification system for stage-III pancreatic cancer patients by utilizing clinical variables. METHODS: We analyzed survival using log-rank tests, univariate Cox-regression models, and Kaplan-Meier survival curves for stage-III pancreatic ductal adenocarcinoma (PDAC) patients from the Taiwan Cancer Registry (TCR). Patients were further divided into subgroups using classification and regression tree (CART) algorithm. All results were validated using the SEER database. RESULTS: Among stage-III PDAC patients, lymph node and tumor grade showed significant association with survival. Patients with N2 stage had higher mortality risks (hazard ratio [HR] = 2.30, 95% confidence interval [CI] 1.71-3.08, p < 0.0001) than N0 patients. Patients with grade 3 also had higher risk of mortality (HR = 3.80, 95% CI 2.25-6.39, p < 0.0001) than grade 1 patients. The CART algorithm stratified stage-III patients into four subgroups with significantly different survival rates. The median survival of the four subgroups was 23.5, 18.4, 14.5, and 9.0 months, respectively (p < 0.0001). Similar results were observed with SEER data. CONCLUSIONS: Lymph node involvement and tumor grade are predictive factors for survival in stage-III PDAC patients. This new precise classification system can be used to guide treatment planning in advanced-stage pancreatic cancer.

Solid Pseudopapillary Neoplasms of the Pancreas Across Races Demonstrate Disparities with Comparably Good Prognosis.

BACKGROUND: Solid pseudopapillary neoplasms (SPNs) of the pancreas are rare with low-grade malignancy and unclarified clinicopathological features. This study aimed to examine their characteristics and re-evaluate current treatments. METHODS: Databases from three sources were screened for patients with SPNs. We compared the perioperative variables, clinical data, overall survival (OS), and prognostic factors for recurrence among the three corresponding cohorts. RESULTS: We identified 286 patients diagnosed with SPNs between 1988 and 2020. Patients were mostly women (81%; median age: 38 years), and peak incidence was observed in women of 20-29 years of age. SPNs had a peak incidence in Asian men at 50-59 years of age (p = 0.002) and a delayed peak incidence in Asian women at 30-39 years of age (p < 0.001). Treatment strategies differed significantly across the institutions and included variations in the number of harvested lymph nodes and rates of vascular resection. Lymph node positivity was the only predictor of postoperative recurrence (odds ratio, 2.2; 95% confidence interval, 1.38-2.99; p = 0.007). Higher rates of lymphovascular invasion (p = 0.02), perineural invasion (p < 0.001), and R1 margin involvement (p < 0.001), as seen in one institution, did not result in poorer long-term survival in terms of the overall (p = 0.43), SPN-specific (p = 0.69), and recurrence-free survivals (p = 0.067). CONCLUSIONS: In contrast to previous findings that SPNs are prevalent in young women, a racial predilection for middle-aged Asian men and a delayed female peak incidence were noted. Parenchyma-preserving pancreatectomy may be an acceptable treatment. Non-radical surgery may be appropriate in patients with multiple comorbidities.

Prognostic validity of the American joint committee on cancer eighth edition staging system for well-differentiated pancreatic neuroendocrine tumors.

BACKGROUND: The American Joint Committee on Cancer (AJCC) made improvements for staging pancreatic neuroendocrine tumors (pNETs) in its 8th Edition; however, multicenter studies were not included. METHODS: We collected multicenter datasets (n = 1,086, between 2004 and 2018) to validate the value of AJCC 8 and other coexisting staging systems through univariate and multivariate analysis for well-differentiated (G1/G2) pNETs. RESULTS: Compared to other coexisting staging systems, AJCC 7 only included 12 (1.1%) patients with stage III tumors. Patients with European Neuroendocrine Tumor Society (ENETS) stage IIB disease had a higher risk of death than patients with stage IIIA (hazard ratio [HR]: 4.376 vs. 4.322). For the modified ENETS staging system, patients with stage IIB disease had a higher risk of death than patients with stage III (HR: 6.078 vs. 5.341). According to AJCC 8, the proportions of patients with stage I, II, III, and IV were 25.7%, 40.3%, 23.6%, and 10.4%, respectively. As the stage advanced, the median survival time decreased (NA, 144.7, 100.8, 72.0 months, respectively), and the risk of death increased (HR: II = 3.145, III = 5.925, and IV = 8.762). CONCLUSION: These findings suggest that AJCC 8 had a more reasonable proportional distribution and the risk of death was better correlated with disease stage.

Transcript annotation tool (TransAT): an R package for retrieving annotations for transcript-specific genetic variants.

BACKGROUND: An individual's genetics play a role in how RNA transcripts are generated from DNA and consequently in their translation into protein. Transcriptional and translational profiling of patients furnishes the information that a specific marker is present; however, it fails to provide evidence whether the marker correlates with response to a therapeutic agent. A comparative analysis of the frequency of genetic variants, such as single nucleotide polymorphisms (SNPs), in diseased and general populations can identify pathogenic variants in individual patients. This is in part because SNPs have considerable effects on protein function and gene expression when they occur in coding regions and regulatory sequences, respectively. Therefore, a tool that can help users to obtain the allele frequency for a corresponding transcript is the need of the day. Several annotation tools such as SNPnexus and VariED are publicly available; however, none of them can use transcript IDs as input and provide the corresponding genomic positions of variants. RESULTS: In this study, we developed an R package, called transcript annotation tool (TransAT), that provides (i) SNP ID and genomic position for a user-provided transcript ID from patients, and (ii) allele frequencies for the SNPs from publicly available global populations. All data elements are extracted, collected, and displayed in an easily downloadable format in two simple command lines. TransAT is available on Windows/Linux/MacOS and is operative for R version 4.0.4 or later. It is available at https://github.com/ShihChingYu/TransAT and can be downloaded and installed using devtools::install_github("ShihChingYu/TransAT", force=T) on the R execution page. Thereafter, all functions can be executed by loading the package into R with library(TransAT). CONCLUSIONS: TransAT is a novel tool that seamlessly provides genetic annotations for queried transcripts. Such easily obtainable information would be greatly advantageous for physicians, assisting them to make individualized decisions about specific drug treatments. Moreover, allele frequencies from user-chosen global ethnic populations will highlight the importance of ethnicity and its effect on patient pathogenicity.

Preoperative sarcopenia is associated with poor overall survival in pancreatic cancer patients following pancreaticoduodenectomy.

OBJECTIVES: To analyze the effect of preoperative body composition on survival in patients with pancreatic cancer following pancreaticoduodenectomy (PD). METHODS: Between October 2005 and August 2018, 116 patients (68 men, 48 women, mean age 66.2 ± 11.9 years) diagnosed with pancreatic adenocarcinoma following PD were retrospectively enrolled. The preoperative CT on vertebral level L3 was assessed for total abdominal muscle area (TAMA), visceral adipose tissue area (VAT), subcutaneous adipose tissue area (SAT), and mean skeletal muscle attenuation (SMD). The clinical data and pathological findings of tumors were collected. The impact of these factors on disease-free survival (DFS) and overall survival (OS) was evaluated by the Kaplan-Meier method and by univariable and multivariable Cox proportional hazards models. RESULTS: The 3-year DFS and OS rates were 8% and 25%, respectively. Of 116 patients, 20 (17.2%), 3 (2.6%), and 46 (39.7%) patients were classified as having sarcopenia, sarcopenic obesity, and myosteatosis, respectively. The VAT-TAMA ratio (1.2 ± 0.7 vs 0.9 ± 0.5, p = 0.01) and the visceral to subcutaneous adipose tissue area ratio (1.3 ± 0.7 vs 0.9 ± 0.5, p = 0.04) were higher in sarcopenic patients than in the nonsarcopenic group. Preoperative sarcopenia and sarcopenic obesity were associated with shorter OS (p = 0.012 and p = 0.041, respectively), but not shorter DFS. Myosteatosis was neither associated with DFS nor OS. On multivariable analysis, sarcopenia was the only significant prognostic factor for OS (p = 0.039). CONCLUSIONS: Preoperative sarcopenia assessed by CT is a poor prognostic factor for OS in pancreatic cancer patients after PD. KEY POINTS: • Sarcopenia and sarcopenic obesity can be evaluated by abdominal CT on L3 level. • Patients with diabetes mellitus (DM) had lower sex-standardized subcutaneous adipose tissue area index and skeletal muscle density and higher visceral to subcutaneous adipose tissue area ratio than did those without DM. • Preoperative sarcopenia, sarcopenic obesity, and new-onset diabetes mellitus may predict poor overall survival in pancreatic cancer patients following pancreaticoduodenectomy.

Recurrence rate and risk factors for recurrence after thoracoscopic surgery for primary spontaneous pneumothorax: A nationwide population-based study.

PURPOSE: This large-scale nationwide population-based study aimed to determine the recurrence rate and risk factors for recurrence after video-assisted thoracoscopic surgery (VATS) for primary spontaneous pneumothorax (PSP). METHODS: This retrospective study used data from the Taiwan National Health Insurance Database to identify individuals who underwent VATS for PSP from 2007 to 2014. All patients were followed up until December 31, 2017. Study variables included demographic characteristics, intensive care unit admission, lung resection status, use of non-steroidal anti-inflammatory drugs (NSAIDs), and hospital level. The primary outcome was 1-year recurrence, and the secondary outcomes were the 1-year rate of reintervention for recurrence and overall recurrence rate. RESULTS: During the study period, 6654 patients underwent VATS for PSP (average age: 23.2 years, 89.1% male), including 910 patients (13.7%) who experienced recurrence within 1 year and 531 patients (8.0%) who required reintervention within 1 year. The overall recurrence rate was 24.8%, with an average follow-up time of 6.7 years. Age ≤18 years and the use of NSAIDs, especially ketorolac, were significant risk factors for 1-year recurrence and overall recurrence. Younger age was a risk factor for 1-year reintervention. In subgroup analysis, NSAID use was a significant risk factor for 1-year recurrence, 1-year reintervention, and overall recurrence in pediatric patients but not in adult patients. CONCLUSIONS: In Taiwan, the 1-year recurrence rate was 13.7% after VATS for PSP. Younger age and the use of NSAIDs, especially ketorolac, were significant risk factors for short- and long-term recurrence after VATS for PSP.

Exploration of Hypoglycemic Activity of Saccharomyces pastorianus Extract and Evaluation of the Molecular Mechanisms.

Although the hypoglycemic potential of brewer's yeast extract has been reported, there is limited information pertaining to the hypoglycemic ingredients of Saccharomyces pastorianus extract and their mechanisms of action available. This study aimed to investigate the in vivo and in vitro hypoglycemic effect of S. pastorianus extract and to elucidate its molecular mechanisms. S. pastorianus extract was mainly composed of proteins followed by carbohydrates. In diabetic rats, oral administration of S. pastorianus extract significantly reduced the levels of plasma glucose and enhanced the activity of hepatic glucose-6-phosphatase dehydrogenase. Treatment with S. pastorianus extract increased the localization of type 4 glucose transporter (GLUT4), PTP, and insulin receptor at 3T3-L1 cell membranes and raised the levels of P38 MAPK, PI3K, and AKT in the cytosol. In agreement with these results, pretreatment of 3T3-L1 cells with inhibitors of PTP, PI3K, Akt/PKB, and p38 MAPK inhibited glucose uptake induced by application of S. pastorianus extract. Most importantly, a 54 kDa protein with hypoglycemic activity was identified and suggested as the major ingredient contributing to the hypoglycemic activity of S. pastorianus extract. In summary, these results clearly confirm the hypoglycemic activity of S. pastorianus extract and provide critical insights into the underlying molecular mechanisms.

Pancreatic neck transection using a harmonic scalpel increases risk of biochemical leak but not postoperative pancreatic fistula after pancreaticoduodenectomy.

BACKGROUND: The effect of a harmonic scalpel on postoperative pancreatic fistula (POPF) has not been addressed. This study assessed the effect of pancreatic neck transection using a harmonic scalpel on rate and severity of POPF after pancreaticoduodenectomy (PD). METHODS: This retrospective analysis included patients who underwent PD at National Taiwan University Hospital between July 2015 and March 2019. We compared rate and severity of POPF between patients who underwent pancreatic neck transection using a harmonic scalpel versus electrosurgical unit. RESULTS: Of 422 consecutive PDs, the pancreatic neck was transected using a harmonic scalpel or electrosurgical unit in 144 and 278 patients, respectively. Use of a harmonic scalpel significantly increased risk of biochemical leak (25.7% versus [vs] 10.8%; P < 0.05) but not clinically relevant POPF (CR-POPF; 30.2% vs 26.4%; P = 0.41). Harmonic transection was an independent predictor of biochemical leak (odds ratio [OR] = 2.93; P < 0.05) but not CR-POPF (OR = 0.83; P = 0.41) or other major complications (OR = 0.72; P = 0.27). There was no significant intergroup difference in postoperative hospital stay. CONCLUSION: Pancreatic neck transection using a harmonic scalpel increased risk of biochemical leak but not CR-POPF or other major complications.

The effect of performing two pancreatoduodenectomies by a single surgical team in one day on surgeons and patient outcomes.

BACKGROUND: The centralization of pancreatoduodenectomy (PD) has been shown to improve patient outcomes. The scheduling of two PDs in one day is one option to shorten the waiting time for patients referred to high volume centers. The effect on the surgical team or patient outcomes of such an approach have not previously been explored. This study aimed to investigate the effect of scheduling two PDs in one day on the surgeon's workload and patient outcomes. METHODS: A retrospective review of patients undergoing PD by a single surgeon between 2007 and 2018 was performed. Patients were allocated into: first PD (FIRSTPD group) or second PD (SECONDPD group) according to the position on the surgical operating list. The intraoperative, postoperative outcomes, and workload (the Surgery Task Load Index; SURG-TLX) were assessed between two groups. RESULTS: A total of 967 (91%) and 101 (9%) patients were included in the FIRSTPD and SECONDPD group, respectively. There were no differences in the duration of surgery (coefficient = -9.65; 95% confidence interval: -29.26 to 9.94; P = 0.334), incidence of major complications (odds ratio = 1.08; 95% confidence interval: 0.67-1.73; P = 0.739), or 90-day mortality (odds ratio = 1.03; 95% confidence interval: 0.12-8.53; P = 0.978) for those patients in the SECONDPD group as compared to the FIRSTPD group. The mean scores of two (physical and temporal demand) of the six SURG-TLX subscales of surgical workload were recorded as significantly higher by surgeons following two PD's as compared to one PD. CONCLUSIONS: Although scheduling a second PD in one day shows no association with adverse patient outcomes, there is an increase in the physical and temporal subscales of surgical workload and consideration should be given to how this could be minimized.

Endoscopic Retrograde Biliary Drainage Causes Intra-Abdominal Abscess in Pancreaticoduodenectomy Patients: An Important But Neglected Risk Factor.

BACKGROUND: Patients with periampullary cancer frequently suffer obstructive jaundice and commonly require preoperative biliary drainage (PBD) for relief and to avoid related complications. Although research has established a correlation between PBD and surgical wound infection, the impact of PBD on major infectious complications (intra-abdominal abscess [IAA]) and overall mortality remains debatable. We hypothesized that PBD could lead to IAA and mortality, and evaluated their correlation in patients undergoing pancreaticoduodenectomy (PD). METHODS: We enrolled patients undergoing PD at an Asian academic medical center between 2007 and 2016. The types of PBD included endoscopic retrograde biliary drainage (ERBD) and percutaneous transhepatic cholangiography and drainage (PTCD). The primary outcome was IAA, defined as the presence of pus or infected fluid inside the abdominal cavity and with documented infectious pathogens. RESULTS: There was one (0.1%) 30-day mortality and eight (0.9%) 90-day mortalities among 899 consecutive patients examined. More than one-quarter of patients had PBD (n = 237, 26.4%; 165 ERBD, 72 PTCD). In the ERBD, PTCD, and non-PBD groups, the IAA rates were 37.0%, 16.7%, and 10.6%, respectively. On multivariate analysis, ERBD (odds ratio 3.67; 95% confidence interval 2.22-6.06; p < 0.001) was the only significant factor associated with IAA. No significant factor was found to analyze variables associated with mortality. CONCLUSIONS: ERBD, but not PTCD, is associated with an increased risk of IAA in patients undergoing PD, which suggests that ERBD should be avoided whenever possible to prevent IAA. Further randomized clinical trials should be conducted to validate this relationship.

Characterization of a Potential Probiotic Lactobacillus brevis RK03 and Efficient Production of γ-Aminobutyric Acid in Batch Fermentation.

Lactic acid bacteria were isolated from fish and evaluated for their γ-aminobutyric acid (GABA)-producing abilities. Out of thirty-two isolates, Lactobacillus brevis RK03 showed the highest GABA production ability. The effects of various fermentation parameters including initial glutamic acid level, culture temperature, initial pH, and incubation time on GABA production were investigated via a singleparameter optimization strategy. For industrial large-scale production, a low-cost GABA producing medium (GM) broth was developed for fermentation with L. brevis RK03. We found that an optimized GM broth recipe of 1% glucose; 2.5% yeast extract; 2 ppm each of CaCO3, MnSO4, and Tween 80; and 10 µM pyridoxal phosphate (PLP) resulted in a maximum GABA yield of 62,523 mg/L after 88 h following the addition of 650 mM monosodium glutamate (MSG), for a conversion rate of 93.28%. Our data provide a practical approach for the highly efficient and economic production of GABA. In addition, L. brevis RK03 is highly resistant to gastric acid and bovine bile salt. Thus, the discovery of Lactobacillus strains with the ability to synthesize GABA may offer new opportunities in the design of improved health-promoting functional foods.

Hydrogel Film-Immobilized Lactobacillus brevis RK03 for γ-Aminobutyric Acid Production.

Hydrogels of 2-hydroxyethyl methacrylate/polyethylene glycol diacrylate (HEMA/PEGDA) have been extensively studied for their use in biomedical and pharmaceutical applications owing to their nontoxic and highly hydrophilic characteristics. Recently, cells immobilized by HEMA/PEGDA hydrogels have also been studied for enhanced production in fermentation. Hydrogel films of HEMA/PEGDA copolymer were generated by Ultraviolet (UV)-initiated photopolymerization. The hydrogel films were used to immobilize viable Lactobacillus brevis RK03 cells for the bioconversion of monosodium glutamate (MSG) to γ-aminobutyric acid (GABA). The mechanical properties and fermentation yields of the L. brevis RK03 cells immobilized on polyacrylate hydrogel films with different monomeric formulations were investigated. Fermentation was carried out in 75 mL de Man, Rogosa and Sharpe (MRS) medium containing various concentrations of MSG. We found that HEMA (93%)/PEGDA (3%) hydrogels (sample H) maximized GABA production. The conversion rate of MSG to GABA reached a maximum value of 98.4% after 240 h. Bioconversion activity gradually declined after 420 h to 83.8% after five cycles of semi-continuous fermentation. Our results suggest that HEMA (93%)/PEGDA (3%) hydrogels have great potential for use in GABA production via semi-continuous fermentation.

Placement of Nasogastric Tubes in Pancreaticoduodenectomy Patients: Switching from Immediate Intraoperative Removal to Avoiding Unnecessary Perioperative Use.

BACKGROUND: The placement of nasogastric tubes (NGTs) in abdominal surgery has been adopted for decades to attenuate ileus and prevent aspiration pneumonia. In the recent era, the guidelines recommend not using NGT routinely, and even in pancreaticoduodenectomy (PD), immediate removal of NGT in operating rooms (ORs) was suggested. However, the clinical outcome and safety of abandoning NGT during the pre-PD and intra-PD periods remain unknown. METHODS: We conducted a single-center retrospective review on adult PD patients aged between 20 and 75 years from 2013 to 2022. The study population was grouped into the NGT group (NGT was placed before PD and immediately removed in the ORs) and the non-NGT group (NGT was not placed preoperatively). Safety was evaluated by the number of adverse events. The primary aim of this study is to evaluate the need of NGT insertion in ORs among PD patients. RESULTS: The case numbers in the NGT and non-NGT groups were 391 and 578, respectively. No case in the non-NGT group needed the intraoperative insertion of NGT. The rate of pulmonary complications was 2.3% in the NGT group compared to 1.6% in the non-NGT group (P = 0.400). Furthermore, there were no significant differences in terms of rates of major complications (12.8% vs. 9.3%, P = 0.089) or mortality (1.0% vs. 1.0%, P =0.980) between the two groups. The rates of the postoperative insertion of NGT in the NGT and non-NGT groups were 2.6% and 2.8% (P = 0.840), respectively. CONCLUSION: For selected PD patients, the placement of NGT during pre-PD and intra-PD periods may be safely omitted. This primary study is considered the first foundation stone in the extension of the element of no NGT in PD.