Inhibitory mechanism of CRISPR-Cas9 by AcrIIC4.

CRISPR-Cas systems act as the adaptive immune systems of bacteria and archaea, targeting and destroying invading foreign mobile genetic elements (MGEs) such as phages. MGEs have also evolved anti-CRISPR (Acr) proteins to inactivate the CRISPR-Cas systems. Recently, AcrIIC4, identified from Haemophilus parainfluenzae phage, has been reported to inhibit the endonuclease activity of Cas9 from Neisseria meningitidis (NmeCas9), but the inhibition mechanism is not clear. Here, we biochemically and structurally investigated the anti-CRISPR activity of AcrIIC4. AcrIIC4 folds into a helix bundle composed of three helices, which associates with the REC lobe of NmeCas9 and sgRNA. The REC2 domain of NmeCas9 is locked by AcrIIC4, perturbing the conformational dynamics required for the target DNA binding and cleavage. Furthermore, mutation of the key residues in the AcrIIC4-NmeCas9 and AcrIIC4-sgRNA interfaces largely abolishes the inhibitory effects of AcrIIC4. Our study offers new insights into the mechanism of AcrIIC4-mediated suppression of NmeCas9 and provides guidelines for the design of regulatory tools for Cas9-based gene editing applications.

PD-1/PD-L1 inhibitors for early and middle stage microsatellite high-instability and stable colorectal cancer: a review.

BACKGROUND: Programmed cell death receptor 1 (PD-1) and programmed cell death ligand 1 (PD-L1) are important immune checkpoint molecules that contribute to tumor immune evasion. However, the main treatment modalities for patients with early and intermediate stage colorectal cancer (CRC) are surgery, and the role of PD-1/PD-L1 inhibitors in these patients is not yet clear. Therefore, this study aims to review the treatment progress of PD-1/PD-L1 inhibitors for early- and intermediate-stage microsatellite high-instability (MSI-H) and stable (MSS) colorectal cancer, in order to provide more options for patients with early- and intermediate-stage colorectal cancer. MATERIALS AND METHODS: A scoping review of clinical trial registries ( Clinicaltrials.gov and EU clinical trial registers) and PubMed/Medline database of trials on PD-1/PD-L1 Inhibitors for early and middle-stage MSI-H and MSS CRC was done up to March 2024. RESULTS: A total of 19 trials related to early to mid-stage MSH-I or MSS CRC were included. Among them, 6 trials are in recruiting status, 3 trials are in active, not recruiting status, 3 trials are completed, 1 trial is terminated, and 1 trial is unknown. Of these, 9 trials involve MSI-H type CRC, and 10 trials involve MSS type CRC. Preclinical phase I/II trials are predominant, with only 3 clinical phase III trials. In trials related to MSI-H type CRC, 4 studies involve PD-1/PD-L1 inhibitors combined with neoadjuvant therapy, and 5 studies involve combination therapy. In trials related to MSS type CRC, 3 studies involve PD-1/PD-L1 inhibitors combined with targeted therapy, 2 studies involve PD-1/PD-L1 inhibitors combined with chemotherapy, 1 study involves PD-1/PD-L1 inhibitor combined immunotherapy, 1 study involves PD-1/PD-L1 inhibitors combined with bacterial therapy, and 3 studies involve PD-1/PD-L1 inhibitors combined with comprehensive therapy. As for primary outcome measures, 4 trials select pathological complete response rates, 3 trials select progression-free survival rate, 3 trials select objective response rate, 3 trials select overall survival rate, 4 trials select disease-free survival rate, 1 trial selects clinical complete response rate, and 1 trial selects percentage of participants with a dose-limiting toxicity. CONCLUSION: For early- and middle-stage MSI-H and MSS CRC, PD-1/PD-L1 inhibitors have shown some therapeutic efficacy, as evidenced by phase I/II studies. However, contemporary trial designs exhibit heterogeneity, with relatively few inclusion criteria, the use of various drug combinations and regimens, and significant variations in reported endpoints. Nevertheless, more double-arm, multicenter, randomized controlled trials are still needed to confirm the efficacy of immunotherapy.

An adaptive frequency-hopping detection for slowly-varying fading dispersive channels.

Frequency hopping (FH) signals have been widely used to improve performance against frequency selective fading phenomenon of underwater channels. However, the channel is slowly varying in regard to changes in weather conditions, and thus the conventional FH detection transmitting signals with fixed frequency cannot guarantee good detection performance in the dynamic underwater environment. To overcome the performance degradation in slowly-varying fading dispersive channels, this paper proposes an adaptive frequency-hopping (AFH) target detection method. Compared with conventional FH detection methods, the AFH can adaptively select the optimal detection frequency based on premeasured background noise and channel frequency response measured from previous experiments. Numerical simulations and lake trials are conducted to verify the effectiveness of the AFH. The simulation results show that the AFH has better detection performance than the conventional FH. The lake trial results have also verified the validity and feasibility of AFH. Importantly, AFH also achieves a better output signal-to-noise ratio under actual noise interference.

Mn Single-Atom Nanozymes with Superior Loading Capability and Superb Superoxide Dismutase-like Activity for Bioassay.

Single-atom nanozymes (SANs) with highly exposed active sites and remarkable catalytic activity have shown noteworthy practicability in heterogeneous catalysis-based bioassay. Nevertheless, most of them were reported with peroxidase-like activity and ordinary loading capability. It is still a challenge to prepare high-loading SANs with desirable superoxide dismutase (SOD)-like activity. In this work, Mn SAN was successfully confined in the frameworks of Prussian blue analogues formed on Ti3C2 MXene sheets with the assistance of massive surfactants, which show a superior loading efficiency of 13.5 wt % (typically <2.0 wt %). The prepared Mn SAN exhibits desirable superoxide radical anion elimination capability because of its SOD-like activity. Moreover, due to the wide-spectrum absorption behavior of the carriers, Mn SAN shows a synergistically quenching efficiency up to 98.89% on the emission of the reactive oxygen species-mediated chemiluminescent (CL) system. Inspired by these features, a CL quenching method was developed on a lateral flow test strip platform by utilizing Mn SAN as a signal quencher and acetamiprid as a model analyte. The method for detecting acetamiprid shows a detection range of 1.0-10,000 pg mL-1 and a limit of detection of 0.3 pg mL-1. Its accuracy has been validated by detecting acetamiprid in medicinal herbs with acceptable recoveries. This work opens an avenue for preparing SANs with a surfactant-assisted protocol and pioneers the study of SANs with SOD-like activity in bioassay.

Safety and feasibility of laparoscopic liver resection for intrahepatic cholangiocarcinoma: a propensity score-matched study.

BACKGROUND: Laparoscopic liver resection (LLR) is controversial in treating intrahepatic cholangiocarcinoma (ICC). Therefore, this study aimed to evaluate the safety and feasibility of LLR for the treatment of ICC and explored the independent factors affecting the long-term prognosis of ICC. METHODS: We included 170 patients undergoing hepatectomy for ICC from December 2010 to December 2021 and divided them into LLR group and open liver resection (OLR) group. We used propensity score matching (PSM) analysis to reduce the impact of data bias and confounding variables and then compared the short-term and long-term prognosis of LLR and OLR in treating ICC; Cox proportional hazards regression model was adopted to explore the independent factors affecting the long-term prognosis of ICC. RESULTS: A total of 105 patients (70 in the LLR group and 35 in the OLR group) were included after 2:1 PSM analysis. There was no difference in demographic characteristics and preoperative indexes between the two groups. The perioperative results of the OLR group were worse than those of the LLR group, that is, the intraoperative blood transfusion rate (24 (68.6) vs 21 (30.0)), blood loss (500 (200-1500) vs 200 (100-525)), and the morbidity of major postoperative complications (9 (25.7) vs 6 (8.5)) in the OLR group were worse than those in LLR group. LLR could enable patients to obtain an equivalent long-term prognosis compared to OLR. The Cox proportional hazards regression model exhibited that no matter before or after PSM, preoperative serum CA12-5 and postoperative hospital stay were independent factors affecting overall survival, while only lymph node metastasis independently influenced recurrence-free survival. CONCLUSIONS: Compared with ICC treated by OLR, the LLR group obtained superior perioperative period outcomes. In the long run, LLR could enable ICC patients to receive an equivalent long-term prognosis compared to OLR. In addition, ICC patients with preoperative abnormal CA12-5, lymph node metastasis, and more extended postoperative hospital stay might suffer from a worse long-term prognosis. However, these conclusions still need multicenter extensive sample prospective research to demonstrate.

The Method and Study of Detecting Phenanthrene in Seawater Based on a Carbon Nanotube-Chitosan Oligosaccharide Modified Electrode Immunosensor.

Phenanthrene (PHE), as a structurally simple, tricyclic, polycyclic aromatic hydrocarbon (PAHs), is widely present in marine environments and organisms, with serious ecological and health impacts. It is crucial to study fast and simple high-sensitivity detection methods for phenanthrene in seawater for the environment and the human body. In this paper, a immunosensor was prepared by using a multi-wall carbon nanotube (MWCNTs)-chitosan oligosaccharide (COS) nanocomposite membrane loaded with phenanthrene antibody. The principle was based on the antibody-antigen reaction in the immune reaction, using the strong electron transfer ability of multi-walled carbon nanotubes, coupled with chitosan oligosaccharides with an excellent film formation and biocompatibility, to amplify the detection signal. The content of the phenanthrene in seawater was studied via differential pulse voltammetry (DPV) using a potassium ferricyanide system as a redox probe. The antibody concentration, pH value, and probe concentration were optimized. Under the optimal experimental conditions, the response peak current of the phenanthrene was inversely proportional to the concentration of phenanthrene, in the range from 0.5 ng·mL-1 to 80 ng·mL-1, and the detection limit was 0.30 ng·mL-1. The immune sensor was successfully applied to the detection of phenanthrene in marine water, with a recovery rate of 96.1~101.5%, and provided a stable, sensitive, and accurate method for the real-time monitoring of marine environments.

Redox-Regulated Magnetic Conversions between Ferro- and Antiferromagnetism in Organic Nitroxide Diradicals.

Redox-induced magnetic transformation in organic diradicals is an appealing phenomenon. In this study, we theoretically designed twelve couples of diradicals in which two nitroxide (NO) radical groups are connected to the redox-active couplers including p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, hexacene-6,15-dione, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene. As evidenced at both the B3LYP and M06-2X levels of theory, the calculations reveal that the magnetic reversal can take place from ferromagnetism to antiferromagnetism, or vice versa, by means of redox method in these designed organic magnetic molecules. It was observed that p-benzoquinonyl, 1,4-naphthoquinyl, 9,10-anthraquinonyl, naphthacene-5,12-dione, pentacene-6,13-dione, and hexacene-6,15-dione-bridged NO diradicals produce antiferromagnetism while their dihydrogenated counterparts exhibit ferromagnetism. Similarly, pyrazinyl, quinoxalinyl, phenazinyl, 5,12-diazanaphthacene, 6,13-diazapentacene, and 6,15-diazahexacene-bridged NO diradicals present ferromagnetism while their dihydrogenated counterparts show antiferromagnetism. The differences in the magnetic behaviors and magnetic magnitudes of each of the twelve couples of diradicals could be attributed to their distinctly different spin-interacting pathways. It was found that the nature of the coupler and the length of the coupling path are important factors in controlling the magnitude of the magnetic exchange coupling constant J. Specifically, smaller HOMO-LUMO (HOMO: highest occupied molecular orbital, LUMO: lowest unoccupied molecular orbital) gaps of the couplers and shorter coupler lengths, as well as shorter linking bond lengths, can attain stronger magnetic interactions. In addition, a diradical with an extensively π-conjugated structure is beneficial to spin transport and can effectively promote magnetic coupling, yielding a large |J| accordingly. That is, a larger spin polarization can give rise to a stronger magnetic interaction. The sign of J for these studied diradicals can be predicted from the spin alternation rule, the shape of the singly occupied molecular orbitals (SOMOs), and the SOMO-SOMO energy gaps of the triplet state. This study paves the way for the rational design of magnetic molecular switches.

[Progress on mRNA vaccine for the prevention of major infectious diseases in humans and animals].

A large number of studies have demonstrated that mRNA vaccine has been characterized as a technique with good safety, strong immunogenicity and high developmental potential, which makes it have broad prospects in immunotherapy. In recent years, the stability and in vivo delivery efficiency of mRNA vaccines have been largely addressed by the progresses in mRNA engineering and delivery innovation. And some mRNA vaccines are now clinical approved or in preclinical trials. Here, we summarize current knowledge on the research advances, technology, and application in major infectious diseases in humans and animals of mRNA vaccines, with the aim to provide a reference for improving the development of novel mRNA vaccines.

Extracellular vesicles from bone marrow stromal cells reduce the impact of stroke on glial cell activation and blood brain-barrier permeability via a putative miR-124/PRX1 signalling pathway.

Ischaemic stroke (IS) is a cerebrovascular disease caused by cerebral infarction and cerebral artery occlusion. In this study, we proposed that EVs from bone marrow stromal cells (BMSCs) could reduce the impact of stroke by reducing the resultant glial cell activation and blood-brain barrier (BBB) leak. We furthermore investigated some of the signalling mechanisms. The transient middle cerebral artery occlusion (t-MCAO) mouse model was established. The behavioural deficits and neuronal damage were verified using Bederson's scale and the 28-point neurological score. The area of cerebral infarction was detected. The expressions of astrocytes/microglia markers and BBB permeability were evaluated by 2,3,5-triphenyltetrazolium chloride (TTC) staining. The internalization of EVs by astrocytes/microglia in the peripheral area was detected by fluorescence labelling. The expressions of astrocyte/microglia markers were measured by RT-qPCR. Levels of TNF-α and IL-1ß in microglia were detected by ELISA. BBB permeability was evaluated. The downstream target genes and pathway of miR-124 were analysed. Microglia/astrocytes were treated by oxygen-glucose deprivation reoxygenation (OGD/R). OGD/R microglia/astrocyte conditioned medium was used to culture bEnd.3 cells. The transendothelial electric resistance (TEER) of bEnd.3 cells was measured, and BBB permeability was characterized. Our results suggested that EVs from BMSCs can indeed reduce the extent of stroke-mediated damage and evidenced that these effects are mediated via expression of the non-coding RNA, miR-124 that may act via the peroxiredoxin 1 (PRX1). Our results provided further motivation to pursue the use of modified EVs as a treatment option for neurological diseases.

Highly Sensitive Chemiluminescent Immunoassay of Mycotoxins Using ZIF-8-Derived Yolk-Shell Co Single-Atom Site Catalysts as Superior Fenton-like Probes.

Superior to traditional nanoscale catalysts, single-atom site catalysts (SASCs) show such merits as maximal catalysis efficiency and outstanding catalytic activity for the construction of analytical methodological platforms. Hereby, an in situ etching strategy was designed to prepare yolk-shell Co SASCs derived from ZIF-8@SiO2 nanoparticles. On the basis of direct chemical interactions between precursors and supports, the Co element with isolated atomic dispersion was anchored on ZIF-8@SiO2 nanoparticles. The Co SASCs possess high Fenton-like activity and thus can catalyze the decomposition of H2O2 to produce massive superoxide radical anions instead of singlet oxygen and hydroxyl radicals. With the activity for producing superoxide radical anion, Co SASCs can greatly improve the chemiluminescent (CL) response of a luminol system by 3133.7 times. Furthermore, the SASCs with active sites of Co-O5 moieties were utilized as the CL probes for establishment of an immunoassay method for sensitive detection of mycotoxins by adopting aflatoxin B1 as a mode analyte. The quantitation range is 10-1000 pg/mL, and the limit of detection is 0.44 pg/mL (3σ) for aflatoxin B1. The proof-of-principle work elucidates the practicability of direct chemical interactions between precursors and supports for forming SASCs with ultrahigh CL response, which can be extended to the exploitation of more sorts of SASCs for tracing biological binding events.

PEGylated Ni Single-Atom Catalysts as Ultrasensitive Electrochemiluminescent Probes with Favorable Aqueous Dispersibility for Assaying Drug-Resistant Pathogens.

Ni single-atom catalysts (SACs) were synthesized by high-temperature calcination of nickel ions and 1,10-phenanthroline on carbon black as a carrier. Benefiting from the ultrahigh atom utilization efficiency, Ni SACs can significantly accelerate decay of dissolved oxygen to generate abundant reactive oxygen species through an oxygen reduction reaction occurring on cathodes. The generated reactive oxygen species can vastly enhance the electrochemiluminescent (ECL) signal of luminol without participation of exogenous co-reactants. To overcome the inherent unfavorable aqueous dispersibility of Ni SACs prepared by the calcination protocol, they were functionalized with highly hydrophilic PEG 2000. Thanks to the abundant carboxyl groups on PEG 2000, the PEGylated Ni SACs (Ni@PEG) can be used as ECL probes to tag biorecognition molecules. In this proof-of-principle work, an ECL biosensor for assaying methicillin-resistant Staphylococcus aureus was developed by using porcine IgG as capture molecule and phage cell-binding domain tagged with Ni@PEG as signal tracer. It shows a broad linear range of 73-7.3 × 106 CFU/mL and a low detection limit of 25 CFU/mL. The recovery values for assaying spiked samples are between 80.8 and 119.2%. It was also utilized to assess MRSA susceptibility to four antibiotics, with results consistent with those obtained by the standard broth microdilution technique. To the best of our knowledge, it is the first time to utilize aqueous dispersible SACs as highly sensitive ECL probes for developing biosensors.

Defective Site Modulation Strategy for Preparing Single Atom-Dispersed Catalysts as Superior Chemiluminescent Signal Probes.

Single atom-dispersed catalysts (SADCs) with highly exposed active sites can be used as sensitive signal probes because of their superior catalytic efficiency. However, the dispersed atoms tend to aggregate, restricting the loading capacity of metal atoms. Herein, the defective sites on Zr-oxo clusters of metal-organic frameworks (MOFs) UiO-66-NH2 were modulated by excessive acetic acid and utilized for confining metal atoms with high loading capacity. To verify the feasibility of the designed strategy, the Co element was loaded onto MOFs UiO-66-NH2 to prepare SADCs with desirable Fenton-like activity. The prepared Co SADCs at a low concentration of 1.0 µg mL-1 are found to boost chemiluminescent (CL) emission for 3700 times due to the significantly improved Co content of 5.55 wt %. The superior CL enhancement efficiency is ascribed to reactive oxygen species generated by the accelerated decay of H2O2. To verify the application potential in CL assay, they were used as signal probes to establish an immunoassay method for carbendazim with a dynamic range of 1.0 pg mL-1 to 25 ng mL-1 and a limit of detection of 0.33 pg mL-1. This defective site modulation strategy paves an avenue for preparing SADCs with a high CL response by improving the loading capacity of metal atoms.

Metabolome and transcriptome analyses identify the plant immunity systems that facilitate sesquiterpene and lignan biosynthesis in Syringa pinnatifolia Hemsl.

BACKGROUND: Syringa pinnatifolia Hemsl. is a shrub belonging to the Oleaceae family. The peeled woody stems and roots of S. pinnatifolia are used in Chinese traditional medicine. This plant has been used for centuries, and modern pharmacological research has revealed its medicinal value. However, the wild populations of S. pinnatifolia have been decreasing, and it has been listed as an endangered plant in China. To elucidate the molecular mechanism leading to the synthesis of the major components of S. pinnatifolia for its further development and sustainable use, this study compared peeled stems and twigs at the metabolic and molecular levels. RESULTS: Peeled stems with the purple substance visible (SSP) and peeled twigs without the purple substance (TSP) were compared at different levels. Microscopic observation showed resin-like fillers in SSP and wood fiber cell walls approximately 1.0 µm thicker than those in TSP (wood fiber cell thickness approximately 2.7 µm). In addition, 104 volatile organic compounds and 870 non-volatile metabolites were detected in the non-targeted and widely-targeted metabolome analyses, respectively. Among the 76 differentially accumulated metabolites (DAMs) detected, 62 were up-accumulated in SSP. Most of these DAMs were terpenes, of which 90% were identified as sesquiterpenes in the volatile organic compound analysis. In the analysis of the non-volatile metabolites, 21 differentially accumulated lignans were identified, of which 18, including five subtypes, were accumulated in SSP. RNA sequencing revealed 4,421 upregulated differentially expressed genes (DEGs) and 5,522 downregulated DEGs in SSP compared with TSP, as well as 33,452 genes that were not differentially expressed. Analysis of the DEGs suggested that sesquiterpenes and lignans were mostly biosynthesized via the mevalonate and phenylpropanoid pathways, respectively. Additionally, in SSP, the enriched Gene Ontology terms included response to biotic stimulus and defense response, while the enriched Kyoto Encyclopedia of Genes and Genomes pathways included plant-pathogen interaction and many other pathways related to plant immunity. CONCLUSIONS: This study provides metabolome and transcriptome information for S. pinnatifolia, suggesting that biotic stimuli, including pathogens, are potential and valuable approaches to promoting the biosynthesis of the metabolites linked to the medicinal properties of this plant.

Laparoscopic Orthotopic Right Hemihepatectomy by Anterior Approach Combined with Inferior Vena Cava Thrombectomy.

BACKGROUND: Hepatocellular carcinoma (HCC) is a highly aggressive malignant disease with a high rate of vascular invasion. (Bruix et al. in Gastroenterology 150:835-853, 2016; Xia et al. in Oncol Lett 20:101, 2020) The conventional surgical strategy for HCC with inferior vena cava (IVC) tumor thrombus is open major surgery with cardiopulmonary bypass, combined with large trauma. (Liu et al. in Eur J Gastroenterol Hepatol 24:186-194, 2012; Bai et al. in J Oncol 2020:3264079, 2020) We report a video of laparoscopic hemihepatectomy and thrombectomy without bypass. As far as we are aware, this is the first report on IVC thrombectomy using a minimally invasive surgical technique. PATIENT: A 52-year-old male was admitted to our institution for a giant hepatic mass in the right liver combined with IVC tumor thrombosis. After 2 months of preoperative systemic treatment, the tumor had reduced to 8 cm and the enhancement of tumor thrombosis in the magnetic resonance imaging (MRI) scan was significantly reduced. METHODS: We used laparoscopy combined with thoracoscopy to perform the surgery, with the patient placed in the supine position. The abdominal trocar position is shown in Fig. 1b. First, we set the blocking band of the suprahepatic IVC in the thoracoscopy. Infrahepatic IVC occlusion and the Pringle maneuver device were prepared for laparoscopy. After fully exposing the retrohepatic IVC, we performed a thrombectomy and IVC suture completely in laparoscopy. Finally, the patient was transferred to the intensive care unit (ICU) for observation. Fig. 1 a Three-dimensional reconstruction model of the patient (a giant hepatic mass and tumor thrombosis extending to the suprahepatic IVC). b Trocar position for the laparoscopic surgery. The patient was placed in the supine position, and the 5, 6, and 7 intercostal axillary fronts were set for the thoracoscopic trocar, while the remaining five abdominal trocars were set for laparoscopic operation. c Retrohepatic IVC before being cut open. The fullness indicates the position of the tumor thrombosis. d Thrombectomy and suture of the IVC. IVC inferior vena cava, TT tumor thrombus RESULTS: Operation time was 495 mins and estimated blood loss was 1000 mL. The patient was discharged on the thirteenth day after the surgery. HCC was confirmed in histopathology. CONCLUSION: Laparoscopic hepatectomy with IVC thrombectomy is a possible operation for HCC combined with IVC tumor thrombus, offering hope for minimally invasive treatment of such cases; however, it is still a highly challenging procedure.

Engineering of a newly isolated Bacillus tequilensis BL01 for poly-γ-glutamic acid production from citric acid.

BACKGROUND: Poly γ-glutamic acid (γ-PGA) is a promising biopolymer for various applications. For glutamic acid-independent strains, the titer of γ-PGA is too low to meet the industrial demand. In this study, we isolated a novel γ-PGA-producing strain, Bacillus tequilensis BL01, and multiple genetic engineering strategies were implemented to improve γ-PGA production. RESULTS: First, the one-factor-at-a-time method was used to investigate the influence of carbon and nitrogen sources and temperature on γ-PGA production. The optimal sources of carbon and nitrogen were sucrose and (NH4)2SO4 at 37 °C, respectively. Second, the sucA, gudB, pgdS, and ggt genes were knocked out simultaneously, which increased the titer of γ-PGA by 1.75 times. Then, the titer of γ-PGA increased to 18.0 ± 0.3 g/L by co-overexpression of the citZ and pyk genes in the mutant strain. Furthermore, the γ-PGA titer reached 25.3 ± 0.8 g/L with a productivity of 0.84 g/L/h and a yield of 1.50 g of γ-PGA/g of citric acid in fed-batch fermentation. It should be noted that this study enables the synthesis of low (1.84 × 105 Da) and high (2.06 × 106 Da) molecular weight of γ-PGA by BL01 and the engineering strain. CONCLUSION: The application of recently published strategies to successfully improve γ-PGA production for the new strain B. tequilensis BL01 is reported. The titer of γ-PGA increased 2.17-fold and 1.32-fold compared with that of the wild type strain in the flask and 5 L fermenter. The strain shows excellent promise as a γ-PGA producer compared with previous studies. Meanwhile, different molecular weights of γ-PGA were obtained, enhancing the scope of application in industry.

Evaluation of cerium oxide as a phosphate binder using 5/6 nephrectomy model rat.

BACKGROUND: The number of chronic kidney disease (CKD) patients continues to increase worldwide. CKD patients need to take phosphate binders to manage serum phosphorus concentrations. Currently, several types of phosphate binder, including lanthanum carbonate, are used. However, they each have disadvantages. METHODS: In this study, we evaluated cerium oxide as a new phosphate binder in vitro and in vivo. First, cerium oxide was mixed with phosphoric acid at pH 2.5 or 7.0, and residual phosphoric acid was measured by absorption photometry using colorimetric reagent. Second, cerium oxide was fed to 5/6 nephrectomy model rats (5/6Nx), a well-known renal damage model. All rats were measured food intake, water intake, feces volume, and urine volume, and collected serum and urine were analyzed for biochemical markers. RESULTS: Cerium oxide can adsorb phosphate at acidic and neutral pH, while lanthanum carbonate, which is a one of popular phosphate binder, does not dissolve at neutral pH. Cerium oxide-treatment reduced serum phosphate concentrations of 5/6Nx rats without an increase in serum alanine transaminase levels that would indicate hepatotoxicity, and cerium oxide-treatment maintained serum creatinine and blood urea nitrogen levels, while those of normal 5/6Nx rats increased slightly. CONCLUSIONS: These results suggest that cerium oxide can be a potential phosphate binder. Decreased body weight gain and increased water intake and urine volume in 5/6Nx rats were thought to be an effect of nephrectomy because these changes did not occur in sham operation rats. Additional investigations are needed to evaluate the longer-term safety and possible accumulation of cerium oxide in the body.

Efficacy of laparoscopic repeat hepatectomy compared with open repeat hepatectomy: a single-center, propensity score matching study.

INTRODUCTION: Laparoscopic repeat hepatectomy (LRH) is considered to be a technically challenging procedure which has not been widely applied. This study aimed to assess the accessibility and security of LRH for patients with hepatic tumor recurrence. METHODS: Between January 2010 and October 2020, we performed 48 LRHs and 31 open repeat hepatectomies (ORHs) for recurrent liver cancer. LRHs were matched to ORHs (1:1) using propensity score matching (PSM) created by comparing preoperative factors. The perioperative data of patients were retrospectively analyzed, including baseline data, operative time, intraoperative blood loss, pathology, days of postoperative stay, complication morbidity, and mortality within 30 days. Overall survival and recurrence-free survival rates with appropriate follow-up were obtained to evaluate the long-term outcomes. RESULTS: Compared with the ORH, LRH was related with shorter operative duration (169.9 versus 232.9 ml, p < 0.01), less intraoperative bleeding (100.0 versus 500.0 ml, p < 0.01), lower rate of blood transfusion (8.3% versus 58.1%, p < 0.01), and shorter hospitalization (5.0 versus 11.0 days, p < 0.01). The median follow-up was 31 months. The LRH 1-, 3-, and 5-year overall survival were 77.1%, 61.6%, and 46.2% versus 82.3%, 66.5%, and 29.5% for ORH (p = 0.77). The 1-, 3-, and 5-year disease-free survival rates of the two groups were 73.4%, 62.0%, and 44.3% versus 66.1%, 44.1%, and 14.7%, respectively (p = 0.22). CONCLUSIONS: Laparoscopic repeated hepatectomy is safe and practicable with great short-term results for selected patients.

Pilot Study of a Virtual Reality Educational Intervention for Radiotherapy Patients Prior to Initiating Treatment.

Virtual reality (VR) presents opportunities for innovative patient educational methods. This study used a combination of subjective questionnaires and objective physiological measures to investigate the impact of a VR radiotherapy (RT) educational system on patients' understanding and anxiety prior to commencing RT. Sixty patients were randomized to control (n = 30) and intervention (n = 30) groups prior to initiating RT. The control group received the standard nursing care process. The intervention group additionally participated in a detailed introduction to RT positioning, procedures, treatments, and other RT-related information via VR education. All patients completed a data collection from pre- and postintervention, which included questions on RT comprehension, anxiety-related scales, and objective physiological data reflecting the patient's psychological state, such as blood pressure, heart rate, and respiration. Both groups had high anxiety levels before the intervention, and there was no significant difference between the questionnaire and physiological data of the two groups. Following the intervention, anxiety scores (state-trait anxiety scale and visual analog scale) of the intervention group decreased significantly compared with those of the control group, and there was a significant decrease in systolic blood pressure (p < 0.05) and increase in cognitive score (p < 0.05). This study reports the positive impact of a virtual reality radiotherapy (VRRT) patient educational system on increasing patient RT comprehension and reducing anxiety. Further work is needed to improve the acceptability of the system to patients and to explore further the impact of VR education on patients' psychological and physical needs.

Preoperative Controlling Nutritional Status (CONUT) score predicts short-term outcomes of patients with gastric cancer after laparoscopy-assisted radical gastrectomy.

BACKGROUND: An emerging prediction tool, the Controlling Nutritional Status (CONUT) score, has shown good assessment ability of postoperative outcomes in cancer patients. This study evaluated the role of the preoperative CONUT score regarding the short-term outcomes of gastric cancer (GC) after laparoscopic gastrectomy. METHODS: Three hundred and nine GC patients undergoing laparoscopic gastrectomy from January 2016 to June 2019 were analysed, retrospectively. The patients were divided into two groups according to the CONUT optimal cut-off value. Clinical characteristics and postoperative complications in the two groups were analysed and evaluated. Risk factors for complications were identified by univariate and multivariate analyses. RESULTS: A total of 309 patients underwent laparoscopic gastrectomy; 91 (29.4%) patients experienced postoperative complications. The preoperative CONUT score showed a good predictive ability for postoperative complications (area under the curve (AUC) = 0.718, Youden index = 0.343) compared with other indices, with an optimal cut-off value of 2.5. Patients with high CONUT score had a significantly higher incidence of overall complications (P < 0.001). Age, haemoglobin, C-reactive protein, red blood cell levels, CONUT scores, surgical procedure type, T1, T4, N0 and N3 pathological TNM classification, and pathological stages of I and III were associated with postoperative complications (P < 0.05). Furthermore, the preoperative CONUT score was identified as an independent risk predictor of postoperative complications (P = 0.012; OR = 2.433; 95% CI, 1.218-4.862) after multivariate analysis. CONCLUSIONS: The preoperative CONUT score is a practical nutritional assessment for predicting short-term outcomes in GC patients after laparoscopy-assisted gastrectomy.

Differentiation and management of hepatobiliary mucinous cystic neoplasms: a single centre experience for 8 years.

BACKGROUND: Hepatobiliary mucinous cystic neoplasms (H-MCNs) are relatively rare cystic neoplasms in the liver. The differential diagnosis of H-MCNs remains big challenging, and the management and prognosis between the hepatic simple cyst (HSC) and H-MCNs are quite different. This study aimed to present our experience in the management of H-MCNs and provide a preoperative H-MCNs risk prediction nomogram to differentiating H-MCNs from liver cystic lesions. METHODS: 29 patients diagnosed with H-MCNs and 75 patients diagnosed with HSC between June 2011 and June 2019 at Zhejiang University School of medicine, Sir Run-Run Shaw Hospital were reviewed in this study. We analyzed the demographic and clinicopathological variables. RESULTS: US, CT, and MRI could accurately diagnose only 3.4%, 46.1%, and 57.1% of H-MCNs, respectively. After univariate analysis and multivariate logistic regression analysis, the variables significantly associated with H-MCNs were enhancement after contrast (p = 0.009), tumour located in the left lobe (p = 0.02) and biliary ductal dilation (p = 0.027). An H-MCNs risk predictive nomogram was constructed, which showed excellent discrimination (areas under the receiver operating characteristic curve were 0.940) and consistent calibration between the predicted probability and actual probability. CONCLUSION: Among patients with H-MCNs, the location of the tumour, enhancement in CT scan, and biliary duct dilation are significantly independent risk factors. The appropriate treatment of H-MCNs is radical resection. Using our Nomogram could facilitate screening and identification of patients with liver cystic lesions.