Water-soluble biodegradable polyesters with pH and ionic responsivity.

The synthesis of novel water-soluble polymers with biodegradability is an effective way to mitigate their negative environmental impacts. In this study, semi-aromatic copolyester poly(butylene succinate-co-butylene terephthalate) (PBST) with exceptional biodegradability is used as the resin matrix. Anionic sodium 1-3-isophthalate-5-sulfonate (SIPA) is introduced as a fourth monomer to prepare random poly(butylene succinate-co-butylene terephthalate-co-butylene 5-sodiosulfoisophthalate) (PBSTS) copolyesters by melt copolymerization. The incorporation of ionic groups enhances the hydrophilicity and water absorption of the copolyesters, resulting in water-soluble materials that exhibit ionic and temperature responsivity. Furthermore, the ionized biodegradable copolyesters demonstrate distinct pH-dependent degradation, which is accelerated at pH = 5.5 and 8.5 but inhibited at pH = 7.2. Degradation assessments in simulated body fluids reveal that the PBSTS copolyesters exhibit significant degradation in gastric fluids at pH = 1.5 with minimal degradation in intestinal fluids at pH = 6.8 and in body fluids at pH = 7.0. This unique degradation performance highlights the potential of these materials for addressing the challenges associated with selective drug delivery and localized controlled release in the human body.

Ionized copolyesters with pH-responsive degradability: Accelerated degradation in specific environments.

The development of environmentally responsive biodegradable polymers is a promising solution for balancing the stability and degradability of biodegradable plastics. In this study, a commercial biodegradable polyester, poly(butylene adipate-co-butylene terephthalate) (PBAT), was used as the substrate and was synthetically modified with a small amount of anionic sodium 1-3-isophthalate-5-sulfonate (SIPA) to obtain the ionized random poly(butylene adipate-co-butylene terephthalate-co-butylene 5-sodiosulfoisophthalate) (PBATS). The introduction of the sodium sulfonate ionic group enhanced the mechanical and heat-resistant properties of the material, while significantly improving the hydrophilicity and water absorption of the copolyesters of PBATSs and endowing them with special pH-responsive degradation properties. Compared with PBAT, PBATS copolyesters could accelerate degradation in acidic or alkaline buffer solutions and natural seawater, while degradation was inhibited in neutral buffer solutions at pH 7.2. Degradation experiments in simulated gastric, intestinal, and body fluids revealed that the copolyester showed specific and rapid degradation in acidic gastric fluids. This environmentally-responsive degradable material greatly expands the special applications of biodegradable polyesters in the fields of environmental remediation and medical applications.

All-natural environmentally degradable poly (butylene terephthalate-co-caprolactone): A theoretical and experimental study of its degradation properties and mechanisms.

The design and production of materials with excellent mechanical properties and biodegradability face significant challenges. Poly (butylene terephthalate-co-caprolactone) copolyesters (PBTCL) is obtained by modifying the engineering plastic polybutylene terephthalate (PBT) with a simple one-pot process using readily biodegradable ε-caprolactone (ε-CL). The material has mechanical properties comparable to those of commercial biodegradable copolyester PBAT. Besides, this copolyester exhibited remarkable degradability in natural environments such as soil and ocean, for example, PBTCL1.91 lost >40 % of its weight after 6 months of immersion in the Bohai Sea. The effect and diversity of specific microorganisms acting on degradation in the ocean were analyzed by 16 s rDNA gene sequencing. Theoretical calculations such as Fukui function and DFT, and experimental studies on water-soluble intermediates and residual matrixes produced after degradation, confirmed that the insertion CL units not only act as active sites themselves susceptible to hydrolysis reactions, but also promote the reactivity of ester bonds between aromatic segments. This work provides insight for the development of novel materials with high performance and environmental degradability.

Fluorescence tracing the degradation process of biodegradable PBAT: Visualization and high sensitivity.

Biodegradable plastics have emerged as a potential solution to the mounting plastic pollution crisis. However, current methods for evaluating the degradation of these plastics are limited in detecting structural changes rapidly and accurately, particularly for PBAT, which contains worrying benzene rings. Inspired by the fact that the aggregation of conjugated groups can endow polymers with intrinsic fluorescence, this work found that PBAT emits a bright blue-green fluoresces under UV irradiation. More importantly, we pioneered a degradation evaluation approach to track the degradation process of PBAT via fluorescence. A blue shift of fluorescence wavelength as the thickness and molecular weight of PBAT film decreased during degradation in an alkali solution was observed. Additionally, the fluorescence intensity of the degradation solution increased gradually as the degradation progressed, and was found to be exponentially correlated with the concentration of benzene ring-containing degradation products following filtration with the correlation coefficient is up to 0.999. This study proposes a promising new strategy for monitoring the degradation process with visualization and high sensitivity.

Enhanced degradation of poly(ethylene terephthalate) by the addition of lactic acid / glycolic acid: composting degradation, seawater degradation behavior and comparison of degradation mechanism.

The degradability improvement of poly(ethylene terephthalate) (PET), one of the most widely used but non-degradable disposable packaging material, is of great significance. However, the balance between degradability and mechanical properties remains a huge challenge. Herein, simple hydroxy acids, lactic acid (LA) and glycolic acid (GA) as easy hydrolysis sites were introduced into non-degradable PET via melt polycondensation. A series of high molecular weight poly(ethylene terephthalate-co-L­lactide) (PETL) and poly(ethylene terephthalate-co-glycolate) (PETG) copolyesters were synthesized with an excellent tensile strength greater than 50 MPa, much higher than that of most commercially available degradable polymers. The introduction of hydroxy acid endows PET with significantly improved composting and seawater degradation performance. Furtherly, the degradation rate of PETG with hydrophilic GA unit was faster than that of PETL, and the mineralization rate of PETG80 reaches 22.0%. The density of functional theory (DFT) calculation revealed that adding hydroxy acid to the PET molecular chain reduced the energy barrier of the hydrolysis reaction. The molecular polarity index (MPI) analysis furtherly confirmed that the higher affinity between the GA unit and water may be the primary reason for the faster degradation of PETG.

A randomised controlled study on the effects of hernial sac stump fenestration on ultrasound seroma prevention in laparoscopic Type III inguinal hernia repair.

BACKGROUND: The incidence of ultrasound seromas has significantly increased after large hernial sac surgery. Several methods are available for preventing ultrasound seromas, but the clinical results are poor. It has also been demonstrated that hernial sac stump fenestration during laparoscopic incisional hernia repair surgery can significantly decrease the incidence of ultrasound seromas. MATERIALS AND METHODS: Ninety patients aged 18-75 years who were treated in our hospital for primary Type III indirect inguinal hernia from March 2017 to March 2018 were randomised to a preventive fenestration group and a control group. All patients underwent transabdominal preperitoneal repair. The number of ultrasound seromas in the inguinal regions and ultrasound seroma volume on day 6 and months 1 and 3 after surgery in the two groups were compared. The secondary outcomes included length of surgery, urinary retention, acute pain, chronic pain, length of hospitalisation, recurrence rate and other complications. RESULTS: There were no significant differences in demographic characteristics. Ultrasound seroma incidence and ultrasound seroma volume on day 6 and months 1 and 3 after surgery were significantly lower in the preventive fenestration group than that in the control group. There were no significant differences in the length of hospitalisation or incidence of acute pain or urinary retention between the two groups. CONCLUSIONS: Hernial sac stump fenestration after hernial sac transection in inguinal hernia repair surgery is a simple method that can effectively reduce post-operative ultrasound seromas.

Molecular Detection and Quantification of Xanthomonas albilineans in Juice from Symptomless Sugarcane Stalks Using a Real-Time Quantitative PCR Assay.

Leaf scald, a bacterial disease caused by Xanthomonas albilineans (Ashby) Dowson, is a major limiting factor for sugarcane production worldwide. Accurate identification and quantification of X. albilineans is a prerequisite for successful management of this disease. A sensitive and robust quantitative PCR (qPCR) assay was developed in this study for detection and quantification of X. albilineans using TaqMan probe and primers targeting a putative adenosine triphosphate-binding cassette (ABC) transporter gene (abc). The novel qPCR assay was highly specific to the 43 tested X. albilineans strains belonging to different pulsed-field gel electrophoresis groups. The detection thresholds were 100 copies/µl of plasmid DNA, 100 fg/µl of bacterial genomic DNA, and 100 CFU/ml of bacterial suspension prepared from pure culture. This qPCR assay was 100 times more sensitive than a conventional PCR assay. The pathogen was detected by qPCR in 75.1% (410/546) of symptomless stalk samples, whereas only 28.4% (155/546) of samples tested positive by conventional PCR. Based on qPCR data, population densities of X. albilineans in symptomless stalks of the same varieties differed between two sugarcane production areas in China, Beihai (Guangxi Province) and Zhanjiang (Guangdong Province), and no significant correlation between these populations was identified. Furthermore, no relationship was found between these populations of the pathogen in asymptomatic stalks and the resistance level of the sugarcane varieties to leaf scald. The newly developed qPCR assay proved to be highly sensitive and reliable for the detection and quantification of X. albilineans in sugarcane stalks.

MSC-derived exosomal miR-34a/c-5p and miR-29b-3p improve intestinal barrier function by targeting the Snail/Claudins signaling pathway.

AIMS: Mesenchymal stem cell (MSC)-derived exosomes (MSCs-exos) regulate biological functions in different diseases, such as liver fibrosis, diabetes, and ischaemic heart injury. However, the function of MSC-derived exosomes on the intestinal barrier and the underlying mechanisms are poorly characterized. MAIN METHODS: The expression of miR-34a/c-5p, miR-29b-3p and Claudin-3 in human normal intestinal tissues and damaged intestinal tissues was evaluated by RT-qPCR. The effect of MSC-secreted exosomes on Claudins in Caco-2 cells was measured by using confocal microscopy, RT-qPCR and Western blot. Dual luciferase reporter assays and RNA immunoprecipitation (RIP) assays were performed to study the interaction between miR-34a/c-5p, miR-29b-3p and Snail. I/R-induced intestinal damage in rats was used to determine the in vivo effect of MSC-exos on intestinal barrier function. KEY FINDINGS: In this study, we found that miR-34a/c-5p, miR-29b-3p and Claudin-3 were downregulated in damaged human intestinal tissues. MSC-exos increased the expression of Claudin-3, Claudin-2 and ZO-1 in Caco-2 cells. Further studies demonstrated that MSC-exos promoted Claudin-3, Claudin-2 and ZO-1 expression in Caco-2 cells by Snail, which was targeted by miR-34a/c-5p and miR-29b-3p. In vivo experiments showed that MSC-derived exosomes could improve I/R-induced intestinal damage through the Snail/Claudins signaling pathway. SIGNIFICANCE: The findings here suggest a novel molecular basis for the therapy of intestinal barrier dysfunction.

Early oral nutrition improves postoperative ileus through the TRPA1/CCK1-R-mediated mast cell-nerve axis.

BACKGROUND: The mechanism of early oral nutrition that regulates the mast cell-nerve axis to improve postoperative ileus (POI) remains unclear. This study aims to investigate whether early oral nutrition can improve POI through Transient receptor potential ankyrin-1 (TRPA1)/cholecystokinin 1 receptor (CCK1-R) in the mast cell-nerve axis. METHODS: Experiment 1: Male Sprague-Dawley (SD) rats were randomly divided into the TRPA1 inhibitor + oral nutrition group (TI + ON + POI), oral nutrition group (ON + POI), POI group (POI) and sham surgery group (Sham). Nine rats in each group were treated. Experiment 2: Primary cultures of mast cells and dorsal root ganglion cells were created, and a non-contact co-culture system was established. The cells were divided into the dorsal root ganglion (DRG) group, mast cell group, DRG + mast cell group, TRPA1 inhibitor or enhancer group, mast cell stabilizer or enhancer group, CCK1-R inhibitor or enhancer group. The results of expression of TRPA1, CCK1-R and histamine in colon tissue, portal vein blood, supernatant or dorsal root ganglia, intestinal transport test and mast cell morphology were analysed. RESULTS: In experiment 1, Early oral nutrition could alleviate the degranulation and activation of mast cells and alleviate the inflammatory reaction of intestinal wall muscles (P<0.05). Early oral nutrition improved POI by stabilizing mast cells with TRPA1. TRPA1 inhibitor decreased CCK1-R concentrations in portal vein blood and CCK1-R expression in colonic smooth muscle (P<0.05). In experiment 2, the change in mast cell function regulated the secretion of CCK1-R by neurons, CCK1-R negatively regulated the degranulation and activation of mast cells (P<0.05), and mast cells positively regulated the expression of TRPA1 protein in DRG (P<0.05). CONCLUSIONS: Early enteral nutrition can improve POI through the TRPA1/CCK1-R-mediated mast cell-nerve axis. TRPA1 positively regulates CCK1-R to stabilize mast cells, but TRPA1 is not the target of the downstream CCK1-R pathway.

Screening and combining serum biomarkers to improve their diagnostic performance in the detection of intestinal barrier dysfunction in patients after major abdominal surgery.

BACKGROUND: The aim of this prospective study was to screen and combine effective biomarkers to improve their diagnostic performance in detecting intestinal barrier dysfunction in patients after major abdominal surgery. METHODS: Patients undergoing major abdominal surgery were enrolled after signing informed consent in this study. The serum concentrations of α-GST, DAO, D-lactate, citrulline and I-FABP were detected 24 hours before and after surgery. The diagnostic performance of five biomarkers on intestinal barrier dysfunction was assessed using logistic regression models and receiver operating characteristic (ROC) curve analyses. RESULTS: Thirty-nine patients with major abdominal surgery were enrolled in and successfully completed this study. ROC analysis revealed that the sensitivities of D-lactate, citrulline and I-FABP were very high (0.91, 0.91 and 1.00, respectively), but the specificities of these biomarkers were less than 0.70. The sensitivity of DAO was very low [0.25; 95% confidence interval (CI), 0.05-0.57], but its specificity was high (0.92; 95% CI, 0.75-0.99). The accuracies of D-lactate and I-FABP were very high, and the areas under the curves (AUCs) of the biomarkers were 0.84 (95% CI, 0.68-0.93) and 0.81 (95% CI, 0.65-0.92), respectively. Different combinations of five biomarkers were also analysed. The sensitivity, specificity and AUC values of the combination of I-FABP, citrulline and D-lactate were 1.00, 0.74 and 0.89, respectively. These results were similar to those derived from the combination of α-GST, DAO, D-lactate, citrulline and I-FABP (P=1.000). CONCLUSIONS: The combination of serum D-lactic acid, citrulline and I-FABP greatly improved the diagnostic performance for identifying intestinal barrier dysfunction in patients after major abdominal surgery.

Accuracy of using serum D-dimer for diagnosis of acute intestinal ischemia: A meta-analysis.

OBJECTIVE: The purpose of this meta-analysis is to comprehensively assess the accuracy of serum D-dimer for the diagnosis of acute intestinal ischemia. METHODS: Diagnostic studies of D-dimer for accurate diagnosis of acute intestinal ischemia were extracted from 6 databases, and prospective and retrospective studies that provided adequate data on sensitivity and specificity were included here. Sensitivity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated. The overall diagnostic performance of D-dimer was assessed by plotting a summary receiver operating characteristic curve (SROC) and calculating the area under the curve (AUC). RESULTS: A total of 1300 patients with suspected acute intestinal ischemia from 12 studies met the inclusion criteria. The combined sensitivity, specificity, PLR, NLR, and DOR were 0.94 (95% CI: 0.87-0.97), 0.50 (95% CI: 0.40-0.61), 1.9 (95% CI: 1.5-2.3), 0.12 (95% CI: 0.05-0.26), and 16 (95% CI: 7-39), respectively. The AUC was 0.81 (95% CI: 0.78-0.84). CONCLUSION: The results of this meta-analysis suggested that plasma D-dimer detection might be a useful means of identifying patients with acute intestinal ischemia of the abdomen.

Comparison of multi-modal early oral nutrition for the tolerance of oral nutrition with conventional care after major abdominal surgery: a prospective, randomized, single-blind trial.

BACKGROUND & AIMS: Early oral nutrition (EON) has been shown to improve recovery of gastrointestinal function, length of stay and mortality after abdominal surgery; however, early oral nutrition often fails during the first week after surgery. Here, a multi-modal early oral nutrition program is introduced to promote recovery of gastrointestinal function and tolerance of oral nutrition. METHODS: Consecutive patients scheduled for abdominal surgery were randomized to the multimodal EON group or a group receiving conventional care. The primary endpoint was the time of first defecation. The secondary endpoints were outcomes and the cost-effectiveness ratio in treating infectious complications. The rate of infectious-free patients was regarded as the index of effectiveness. RESULTS: One hundred seven patients were randomly assigned to groups. Baseline characteristics were similar for both groups. In intention-to-treat analysis, the success rate of oral nutrition during the first week after surgery in the multimodal EON group was 44 (83.0%) versus 31 (57.4%) in the conventional care group (P = 0.004). Time to first defecation, time to flatus, recovery time of bowel sounds, and prolonged postoperative ileus were all less in the multimodal EON group (P < 0.05). The median postoperative length of stay in the multimodal EON group was 8 days (6, 12) versus 10 days (7, 18) in the conventional care group (P < 0.001). The total cost of treatment and nutritional support were also less in the multi-modal early oral nutrition group (P < 0.001). The effectiveness was 84.9 and 79.9% in the multimodal EON and conventional care group, respectively (P = 0.475). However, the cost-effectiveness ratio was USD 537.6 (506.1, 589.3) and USD 637.8 (593.9, 710.3), respectively (P < 0.001). CONCLUSION: The multi-modal early oral nutrition program was an effective way to improve tolerance of oral nutrition during the first week after surgery, decrease the length of stay and improve cost-effectiveness after abdominal surgery. TRIAL REGISTRATION: Registration number: ChiCTR-TRC-14004395 . Registered 15 March 2014.

Accuracy of the serum intestinal fatty-acid-binding protein for diagnosis of acute intestinal ischemia: a meta-analysis.

Numerous studies have investigated the utility of serum intestinal fatty-acid binding protein (I-FABP) in differentiating acute intestinal ischemia from acute abdomen. However, the results remain controversial. The aim of this meta-analysis is to determine the overall accuracy of serum I-FABP in the diagnosis of acute intestinal ischemia. Publications addressing the accuracy of serum I-FABP in the diagnosis of ischemic bowel diseases were selected from databases. The values of true-positive (TP), true-negative (TN), false-positive (FP), and false-negative (FN) were extracted or calculated for each study. Pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were calculated. The overall diagnostic performance was assessed using a summary receiver operating characteristic curve (SROC) and area under curve (AUC). Nine studies that collectively included 1246 patients met the eligible criteria. The pooled sensitivity, specificity, DOR, PLR, and NLR were 0.80 (95% CI: 0.72-0.86), 0.85 (95% CI: 0.73-0.93), 24 (95% CI: 9-65), 5.5 (95% CI: 2.8-10.8) and 0.23 (95% CI: 0.15-0.35), respectively. The AUC was 0.86 (95% CI: 0.83-0.89). The meta-analysis carried out in this report suggests that the I-FABP may be a useful diagnostic tool to confirm acute intestinal ischemia in acute abdomen, but better-designed trials are still required to confirm our findings.

Impact of nutritional support that does and does not meet guideline standards on clinical outcome in surgical patients at nutritional risk: a prospective cohort study.

OBJECTIVE: To investigate the impact of nutritional support on clinical outcomes in patients at nutritional risk who receive nutritional support that meets guideline standards and those who do not. METHODS: This prospective cohort study enrolled hospitalized patients from the Second Affiliated Hospital of Kunming Medical University from February 2010 to June 2012. The research protocols were approved by the university's ethics committee, and the patients signed informed consent forms. The clinical data were collected based on nutritional risk screening, administration of enteral and parenteral nutrition, surgical information, complications, and length of hospital stay. RESULTS: During the study period, 525 patients at nutritional risk were enrolled in the cohorts. Among patients who received nutritional support that met the guideline standards (Cohort 1), the incidence of infectious complications was lower than that in patients who did not meet guideline standards (Cohort 2) (17.1 % vs. 26.9 %, P = 0.01). Subgroup analysis showed that individuals who received a combination of parenteral nutrition (PN) and enteral nutrition (EN) for 7 or more days had a significantly lower incidence of infectious complications (P = 0.001) than those who received only PN for 7 or more days or those who received nutritional support for less than 7 days or at less than 10 kcal/kg/d. Binary logistic regression analysis showed that, after adjusting for confounding factors, nutritional support that met guideline standards for patients with nutritional risk was a protective factor for complications (OR: 0.870, P < 0.002). CONCLUSIONS: In patients at nutritional risk after abdominal surgery, nutritional support that meets recommended nutrient guidelines (especially regimens involving PN + EN ≥ 7 days) might decrease the incidence of infectious complications and is worth recommending; however, well-designed trials are needed to confirm our findings. Nutritional support that does not meet the guideline standards is considered clinically undesirable.