Cardiac-specific deletion of BRG1 ameliorates ventricular arrhythmia in mice with myocardial infarction.

Malignant ventricular arrhythmia (VA) after myocardial infarction (MI) is mainly caused by myocardial electrophysiological remodeling. Brahma-related gene 1 (BRG1) is an ATPase catalytic subunit that belongs to a family of chromatin remodeling complexes called Switch/Sucrose Non-Fermentable Chromatin (SWI/SNF). BRG1 has been reported as a molecular chaperone, interacting with various transcription factors or proteins to regulate transcription in cardiac diseases. In this study, we investigated the potential role of BRG1 in ion channel remodeling and VA after ischemic infarction. Myocardial infarction (MI) mice were established by ligating the left anterior descending (LAD) coronary artery, and electrocardiogram (ECG) was monitored. Epicardial conduction of MI mouse heart was characterized in Langendorff-perfused hearts using epicardial optical voltage mapping. Patch-clamping analysis was conducted in single ventricular cardiomyocytes isolated from the mice. We showed that BRG1 expression in the border zone was progressively increased in the first week following MI. Cardiac-specific deletion of BRG1 by tail vein injection of AAV9-BRG1-shRNA significantly ameliorated susceptibility to electrical-induced VA and shortened QTc intervals in MI mice. BRG1 knockdown significantly enhanced conduction velocity (CV) and reversed the prolonged action potential duration in MI mouse heart. Moreover, BRG1 knockdown improved the decreased densities of Na+ current (INa) and transient outward potassium current (Ito), as well as the expression of Nav1.5 and Kv4.3 in the border zone of MI mouse hearts and in hypoxia-treated neonatal mouse ventricular cardiomyocytes. We revealed that MI increased the binding among BRG1, T-cell factor 4 (TCF4) and ß-catenin, forming a transcription complex, which suppressed the transcription activity of SCN5A and KCND3, thereby influencing the incidence of VA post-MI.

Effect of alfalfa supplementary change dietary non-fibrous carbohydrate (NFC) to neutral detergent fiber (NDF) ratio on rumen fermentation and microbial function in Gansu alpine fine wool sheep (Ovis aries).

Bodyweight loss and rumen microbial dysfunction of grazing sheep was a challenge for the sheep production industry during cold season, which were considered to correlated with under-roughage-feeding. Alfalfa is a good roughage supplementary for ruminants, which can improve grazing sheep bodyweight-loss and rumen microbial dysfunction during grass-withering period. This study evaluated the effects of alfalfa hay supplementary change dietary non-fibrous carbohydrate/neutral detergent fiber (NFC/NDF) ratios on rumen fermentation and microbial function of Gansu alpine fine wool sheep during extreme cold season. 120 ewes (3-4 yrs) with an average body weight of 28.71 ± 1.22 kg were allocated randomly into three treatments, and fed NFC/NDF of 1.92 (H group), 1.11 (M group), and 0.68 (L group), respectively. This study was conducted for 107 d, including 7 d of adaption to the diets. The rumen fermentation parameters and microbial characteristics were measured after the end of feeding trials. The results showed that the concentrations of sheep body weight, nitrogen components (Total-N, Soluble protein-N and Ammonia-N), blood biochemical indices (LDH, BUN and CHO) and ruminal volatile fatty acids (TVFA and propionate) significantly increased with an increase in the proportion of NFC/NDF ratios (p < .05), and the acetate and acetate/propionat ratio presented a contrary decreasing trend (p < .05). A total of 1018 OTUs were obtained with 97% consistency. Ruminococcus, Ruminococcaceae and Prevotella were observed as the predominant phyla in ruminal fluid microbiota. Higher NFC/NDF ratios with Alfalfa supplementary increased the richness and diversity of ruminal fluid microbiota, and decreased ruminal fluid microbiota beta-diversity. Using clusters of orthologous groups (COG), the ruminal fluid microbiota of alfalfa supplementary feeding showed low immune pathway and high carbohydrate metabolism pathway. In summary, the study suggested that there was an increasing tendency in dietary NFC/NDF ratio of 1.92 in body weight, ruminal fermentation, microbial community composition and fermentation characteristics through developing alfalfa supplementary system.

Acute Necrotizing Pancreatitis Complicated With Sinistral Portal Hypertension And Mechanical Obstruction Of The Colon: A Case Report.

Acute necrotizing pancreatitis (ANP) is often associated with acute necrotic collection (ANC) or walled-off necrosis (WON). Due to the close anatomical connection between the pancreas, the spleen, and the transverse colon, necrotizing pancreatitis is often combined with spleen or colon involvement. Gastrointestinal dysfunction usually caused by pancreatitis leads to paralytic intestinal obstruction. However, pancreatitis combined with mechanical colonic obstruction is extremely rare. It can easily be misdiagnosed as malignant intestinal obstruction, and diagnosing the cause of intestinal obstruction becomes more critical when accompanied by Sinistral portal hypertension (SPH). Surgical resection is the primary method for the previous occurrence of colonic complications. In this case report, upon admission, a 37-year-old patient was diagnosed with acute necrotizing pancreatitis with sinistral portal hypertension. On the 6th day after admission, the patient developed a sudden colonic obstruction. After identifying the cause, the patient underwent a transanal decompression tube and minimally invasive necrosectomy, avoiding colon resection. In acute necrotizing pancreatitis combined with colonic mechanical obstruction, it is essential to clarify the etiology, and focus treatment on clearing the peripancreatic necrotic tissue, non-surgical treatment to deal with colonic obstruction is feasible, and the principle of individualized treatment should be used throughout the disease.

Independent Monte Carlo dose calculation identifies single isocenter multi-target radiosurgery targets most likely to fail pre-treatment measurement.

PURPOSE: For individual targets of single isocenter multi-target (SIMT) Stereotactic radiosurgery (SRS), we assess dose difference between the treatment planning system (TPS) and independent Monte Carlo (MC), and demonstrate persistence into the pre-treatment Quality Assurance (QA) measurement. METHODS: Treatment plans from 31 SIMT SRS patients were recalculated in a series of scenarios designed to investigate sources of discrepancy between TPS and independent MC. Targets with > 5% discrepancy in DMean[Gy] after progressing through all scenarios were measured with SRS MapCHECK. A matched pair analysis was performed comparing SRS MapCHECK results for these targets with matched targets having similar characteristics (volume & distance from isocenter) but no such MC dose discrepancy. RESULTS: Of 217 targets analyzed, individual target mean dose (DMean[Gy]) fell outside a 5% threshold for 28 and 24 targets before and after removing tissue heterogeneity effects, respectively, while only 5 exceeded the threshold after removing effect of patient geometry (via calculation on StereoPHAN geometry). Significant factors affecting agreement between the TPS and MC included target distance from isocenter (0.83% decrease in DMean[Gy] per 2 cm), volume (0.15% increase per cc), and degree of plan modulation (0.37% increase per 0.01 increase in modulation complexity score). SRS MapCHECK measurement had better agreement with MC than with TPS (2%/1 mm / 10% threshold gamma pass rate (GPR) = 99.4 ± 1.9% vs. 93.1 ± 13.9%, respectively). In the matched pair analysis, targets exceeding 5% for MC versus TPS also had larger discrepancies between TPS and measurement with no GPR (2%/1 mm / 10% threshold) exceeding 90% (71.5% ± 16.1%); whereas GPR was high for matched targets with no such MC versus TPS difference (96.5% ± 3.3%, p = 0.01). CONCLUSIONS: Independent MC complements pre-treatment QA measurement for SIMT SRS by identifying problematic individual targets prior to pre-treatment measurement, thus enabling plan modifications earlier in the planning process and guiding selection of targets for pre-treatment QA measurement.

STE20 phosphorylation of AMPK-related kinases revealed by biochemical purifications combined with genetics.

We have recently purified mammalian sterile 20 (STE20)-like kinase 3 (MST3) as a kinase for the multifunctional kinases, AMP-activated protein kinase-related kinases (ARKs). However, unresolved questions from this study, such as remaining phosphorylation activities following deletion of the Mst3 gene from human embryonic kidney cells and mice, led us to conclude that there were additional kinases for ARKs. Further purification recovered Ca2+/calmodulin-dependent protein kinase kinases 1 and 2 (CaMKK1 and 2), and a third round of purification revealed mitogen-activated protein kinase kinase kinase kinase 5 (MAP4K5) as potential kinases of ARKs. We then demonstrated that MST3 and MAP4K5, both belonging to the STE20-like kinase family, could phosphorylate all 14 ARKs both in vivo and in vitro. Further examination of all 28 STE20 kinases detected variable phosphorylation activity on AMP-activated protein kinase (AMPK) and the salt-inducible kinase 3 (SIK3). Taken together, our results have revealed novel relationships between STE20 kinases and ARKs, with potential physiological and pathological implications.

Biochemical purification uncovers mammalian sterile 3 (MST3) as a new protein kinase for multifunctional protein kinases AMPK and SIK3.

The AMP-activated protein kinase (AMPK) and AMPK-related kinase salt-inducible kinase 3 (SIK3) regulate many important biological processes ranging from metabolism to sleep. Liver kinase B1 is known to phosphorylate and activate both AMPK and SIK3, but the existence of other upstream kinases was unclear. In this study, we detected liver kinase B1-independent AMPK-related kinase phosphorylation activities in human embryonic kidney cells as well as in mouse brains. Biochemical purification of this phosphorylation activity uncovered mammalian sterile 20-like kinase 3 (MST3). We demonstrate that MST3 from human embryonic kidney cells could phosphorylate AMPK and SIK3 in vivo. In addition, recombinant MST3 expressed in and purified from Escherichia coli could directly phosphorylate AMPK and SIK3 in vitro. Moreover, four other members of the MST kinase family could also phosphorylate AMPK or SIK3. Our results have revealed new kinases able to phosphorylate and activate AMPK and SIK3.

Association of maternal pre-pregnancy dietary intake with adverse maternal and neonatal outcomes: A systematic review and meta-analysis of prospective studies.

This study aimed to summarize the evidence regarding the effects of dietary intake before conception on pregnancy outcomes by performing a systematic review and meta-analysis of prospective studies. Electronic databases were searched from inception up to August 2021. Overall, 65 studies involving 831 798 participants were included and 38 studies were quantitatively pooled. With regard to maternal outcomes, pre-pregnancy intake of fried food, fast food, red and processed meat, heme iron and a low-carbohydrate dietary pattern was positively associated with the risk of gestational diabetes mellitus (GDM) (all P < 0.05). However, a high dietary fiber intake and folic acid supplementation were negatively associated with GDM risk (both P < 0.05). With regard to neonatal outcomes, maternal caffeine intake before pregnancy significantly increased the risk of spontaneous abortion, while folic acid supplementation had protective effects on total adverse neonatal outcomes, preterm birth, and small-for-gestational age (SGA, all P < 0.05). However, no significant associations were found between adverse pregnancy outcomes (i.e., GDM and SGA) and the pre-pregnancy dietary intake of sugar-sweetened beverages, potato, fish, and carbohydrates and the Healthy Eating Index. Our study suggests that maintaining a healthy diet before conception has significant beneficial effects on pregnancy outcomes.Supplemental data for this article is available online at https://doi.org/10.1080/10408398.2021.1989658.

Semirational Engineering of a Thermostable Carbonyl Reductase for the Precision Synthesis of (2R,3R)-2-Methyl-2-benzyl-3-hydroxycyclopentanone and Its Analogues.

2,2-Disubstituted-3-hydroxycyclopentanones are important chiral intermediates for natural products and pharmaceuticals. Through semirational engineering of a thermostable carbonyl reductase CBCR from Cupriavidus sp. BIS7, a mutant L91C/F93I was obtained. Mutant L91C/F93I showed 4- to 36-fold enhanced activities toward 2-methyl-2-benzyl-1,3-cyclopentanedione and its analogues, affording the (2R,3R)-stereoisomers with >99% ee and >99% de. Enzyme-substrate docking studies were performed to reveal the molecular basis for the activity and stereoselectivity improvements.

Engineering a Carbonyl Reductase for Scalable Preparation of (S)-3-Cyclopentyl-3-hydroxypropanenitrile, the Key Building Block of Ruxolitinib.

(S)-3-Cyclopentyl-3-hydroxypropanenitrile is the key precursor for the synthesis of ruxolitinib. The bioreduction of 3-cyclopentyl-3-ketopropanenitrile (1 a) offers an attractive method to access this important compound. A carbonyl reductase (PhADH) from Paraburkholderia hospita catalyzed the reduction of 1 a giving the (S)-alcohol (1 b) with 85 % ee. Rational engineering of PhADH resulted in a double mutant H93C/A139L, which enhanced the enantioselectivity from 85 % to >98 %, as well as a 6.3-fold improvement in the specific activity. The bioreduction of 1 a was performed at 200 g/L (1.5 M) substrate concentration, leading to isolation of (S)-1 b in 91 % yield. Similarly, using this mutant enzyme, 3-cyclohexyl-3-ketopropanenitrile (2 a) and 3-phenyl-3-ketopropanenitrile (3 a) were reduced at high concentration affording the corresponding alcohols in >99 % ee, and 90 % and 92 % yield, respectively. The results showed that the variant H93C/A139L was a powerful biocatalyst for reduction of ß-substituted-ß-ketonitriles.

MiR-325-3p Alleviates Acute Pancreatitis via Targeting RIPK3.

BACKGROUND AND AIMS: Acute pancreatitis (AP) is an acute inflammatory disease that can lead to death. Mir-325-3p is strongly and abnormally expressed in many diseases, necessitating exploration of its function and mechanism in AP. METHODS: Blood samples from AP patients and mice were analyzed. The expression levels of miR-325-3p in AP patients and mouse were detected. Whether miR-325-3p targets RIPK3 gene was predicted by TargetScan online database and dual luciferase reporter assay. In vitro experiments verified the effect of miR-325-3p overexpression on caerulein-induced MPC83 pancreatic acinar cancer cell line. In vivo experiments verified the effect of overexpression of miR-325-3p on the disease degree of pancreatic tissues in AP mice. RESULTS: Analysis of blood samples from AP patients and experiments in mice demonstrated that expression of miR-325-3p was significantly reduced during the process of AP in humans and mice. Predicted using the TargetScan online database and through dual luciferase reporter assay detection, miR-325-3p directly targets the RIPK3 gene. In vitro experiments revealed that overexpression of miR-325-3p reversed caerulein-induced apoptosis and necroptosis in MPC83 pancreatic acinar cancer cell line. We used Z-VAD-FMK to assess necroptosis and demonstrated that miR-325-3p targets necroptosis to reduce cell damage. In subsequent experiments in mice, we verified that overexpression of miR-325-3p reduces inflammation, edema, hemorrhage, and necrosis in acute pancreatitis. Characteristic western blot, immunohistochemistry, and transmission electron microscopy results revealed that overexpression of miR-325-3p reduces the severity of acute pancreatitis by inhibiting pancreatic necroptosis in AP mice. CONCLUSIONS: The current research results indicate that miR-325-3p directly targets RIPK3 and exerts a protective role in mouse AP. Necroptosis is still the primary mechanism of RIPK3 regulation. MiR-325-3p inhibits acute pancreatitis by targeting RIPK3-dependent necroptosis, which may represent a novel treatment method for acute pancreatitis.

Translation and validation of the Chinese version of the orthorexia nervosa assessment questionnaires among college students.

PURPOSE: The main objective of the study was to translate, validate, and compare the Chinese ORTO scales (ORTO-15 and ORTO-R). The secondary objective was to assess factors that may be related with risk of orthorexia nervosa (ON). METHODS: Two cross-sectional surveys were conducted on March-to-June 2021 for ORTO-15 and April 2022 for ORTO-R. ORTO questionnaires were translated into Chinese using the forward-backward-forward method. Exploratory factor analysis (EFA), discriminant validity and confirmatory factor analysis (CFA) were used to examine the construct validity of the questionnaires. The internal consistency was assessed using the Cronbach alpha coefficient and the test-retest reliability. Multivariate linear regression analysis was used to explore potential factors related with ON scores. RESULTS: Totally, 1289 and 1084 eligible participants were included for assessment of ORTO-15 and ORTO-R, with the mean age of 20.9 ± 2.0 years and 21.0 ± 2.3 years. The internal consistency of Chinese ORTO-15 scale and ORTO-R scale were both satisfactory (α = 0.79, ICC = 0.79; α = 0.77, ICC = 0.82). However, all ORTO-15 models showed a poor fit using CFA whereas the ORTO-R was characterized by acceptable goodness-of-fit. Multivariate linear regression indicated that physical activities and mental disorders were positively associated with ON risk assessed by both ORTO-R and ORTO-15. CONCLUSION: The Chinese ORTO-R scale was a more reliable tool to screen for ON tendencies than the Chinese version of ORTO-15. Mental disorders and physical activities might be associated with the increased ON risk. LEVEL OF EVIDENCE: Level V (descriptive cross-sectional study).

Asymmetric Synthesis of N-Substituted 1,2-Amino Alcohols from Simple Aldehydes and Amines by One-Pot Sequential Enzymatic Hydroxymethylation and Asymmetric Reductive Amination.

The chiral N-substituted 1,2-amino alcohol motif is found in many natural and synthetic bioactive compounds. In this study, enzymatic asymmetric reductive amination of α-hydroxymethyl ketones with enantiocomplementary imine reductases (IREDs) enabled the synthesis of chiral N-substituted 1,2-amino alcohols with excellent ee values (91-99 %) in moderate to high yields (41-84 %). Furthermore, a one-pot, two-step enzymatic process involving benzaldehyde lyase-catalyzed hydroxymethylation of aldehydes and subsequent asymmetric reductive amination was developed, offering an environmentally friendly and economical way to produce N-substituted 1,2-amino alcohols from readily available simple aldehydes and amines. This methodology was then applied to rapidly access a key synthetic intermediate of anti-malaria and cytotoxic tetrahydroquinoline alkaloids.

Characteristics of and risk factors for biliary pathogen infection in patients with acute pancreatitis.

BACKGROUND: Infection in patients with acute pancreatitis, especially severe acute pancreatitis patients, is a common and important phenomenon, and the distributions and drug resistance profiles of bacteria causing biliary infection and related risk factors are dynamic. We conducted this study to explore the characteristics of and risk factors for bacterial infection in the biliary tract to understand antimicrobial susceptibility, promote the rational use of antibiotics, control multidrug-resistant bacterial infections and provide guidance for the treatment of acute pancreatitis caused by drug-resistant bacteria. METHODS: The distribution of 132 strains of biliary pathogenic bacteria in patients with acute pancreatitis from January 2016 to December 2020 were analyzed. We assessed drug resistance in the dominant Gram-negative bacteria and studied the drug resistance profiles of multidrug-resistant bacteria by classifying Enterobacteriaceae and nonfermentative bacteria. We then retrospectively analyzed the clinical data and risk factors associated with 72 strains of Gram-negative bacilli, which were divided into multidrug-resistant bacteria (50 cases) and non-multidrug-resistant bacteria (22 cases). RESULTS: The main bacteria were Escherichia coli, Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli had a 66.67% detection rate. Acinetobacter baumannii had more than 50.00% drug resistance to carbapenems, ESBL-producing Klebsiella pneumoniae had 100.00% drug resistance, and Pseudomonas aeruginosa had 66.67% resistance to carbapenems. Multivariate logistic regression analysis suggested that the administration of third- or fourth-generation cephalosporins was an independent risk factor for Gram-negative multidrug-resistant biliary bacterial infection in acute pancreatitis patients. CONCLUSION: Drug resistance among biliary pathogens in acute pancreatitis patients remains high; therefore, rational antimicrobial drug use and control measures should be carried out considering associated risk factors to improve diagnosis and treatment quality in acute pancreatitis patients.

Per- and polyfluoroalkyl substances exposure during pregnancy and adverse pregnancy and birth outcomes: A systematic review and meta-analysis.

BACKGROUND: Exposure to per- and polyfluoroalkyl substances (PFAS) during pregnancy has been suggested to be associated with adverse pregnancy and birth outcomes; however, the findings have been inconsistent. We aimed to conduct a systematic review and meta-analysis to provide an overview of these associations. METHODS: The online databases PubMed, EMBASE and Web of Science were searched comprehensively for eligible studies from inception to February 2021. Odds ratios (ORs) and 95% confidence intervals (CIs) were pooled using random- or fixed-effects models, and dose-response meta-analyses were also conducted when possible. FINDINGS: A total of 29 studies (32,905 participants) were included. The pooled results demonstrated that perfluorooctane sulfonate (PFOS) exposure during pregnancy was linearly associated with increased preterm birth risk (pooled OR per 1-ng/ml increase: 1.01, 95% CIs: 1.00-1.02, P = 0.009) and perfluorononanoate (PFNA) and perfluorooctanoate (PFOA) exposure showed inverted U-shaped associations with preterm birth risk (P values for the nonlinear trend: 0.025 and 0.030). Positive associations were also observed for exposure to perfluorodecanoate (PFDA) and miscarriage (pooled OR per 1-ng/ml increase: 1.87, 95% CIs: 1.15-3.03) and PFOS and preeclampsia (pooled OR per 1-log increase: 1.27, 95% CIs: 1.06-1.51), whereas exposure to perfluoroundecanoate (PFUnDA) was inversely associated with preeclampsia risk (pooled OR per 1-log increase: 0.81, 95% CIs: 0.71-0.93). Based on individual evidence, detrimental effects were observed between PFDA exposure and small for gestational age and between PFOA and PFOS and intrauterine growth restriction. No significant associations were found between pregnancy PFAS exposure and other adverse pregnancy outcomes (i.e., gestational diabetes mellitus, pregnancy-induced hypertension, low birth weight, and large and small for gestational age). INTERPRETATION: Our findings indicated that PFOS, PFOA and PFNA exposure during pregnancy might be associated with increased preterm birth risk and that PFAS exposure might be associated with the risk of miscarriage and preeclampsia. Due to the limited evidence obtained for most associations, additional studies are required to confirm these findings.

Association between blood urea nitrogen and incidence of type 2 diabetes mellitus in a Chinese population: a cohort study.

To examine the association between blood urea nitrogen (BUN) and risk of type 2 diabetes (T2DM) among Chinese adults, we performed an ongoing cohort study of 38578 Chinese adults (56.3% males; average age, 41.6 y) who underwent repeated health check-up examinations between 2009 and 2016 and without T2DM at baseline. During follow-up, incident T2DM cases were identified based on self-report, medication use, measurements of fasting plasma glucose, 2 h post oral glucose, or haemoglobinA1c. 2009 (5.2%) cases confirmed with incident T2DM were identified during median follow-up of 3.1 years. With increasing quartiles of BUN levels, the incidences of T2DM gradually increased with 0.69%, 1.11%, 1.53%, and 1.87% for quartile 1 to quartile 4 (p trend <0.001). Compared with quartile 1, the multivariate-adjusted hazard ratios (HRs) and its 95% confidence intervals (95% CIs) for T2DM risk were 1.16 (0.97-1.38) for quartile 2, 1.28 (1.07-1.51) for quartile 3, and 1.28 (1.08-1.52) for quartile 4 (p trend = 0.005). HR for per each standard deviation increase in BUN level was 1.10 (1.04-1.16) (p trend <0.001). This association tended to be more pronounced in those with a lower body mass index at baseline (p-interaction <0.001). Our results suggested that BUN levels were positively associated with incident T2DM risk among Chinese adults. Future prospective investigations in other populations are necessary to confirm our findings.

Inverting the Enantiopreference of Nitrilase-Catalyzed Desymmetric Hydrolysis of Prochiral Dinitriles by Reshaping the Binding Pocket with a Mirror-Image Strategy.

A mirror-image strategy, that is, symmetry analysis of the substrate-binding pocket, was applied to identify two key amino acid residues W170 and V198 that possibly modulate the enantiopreference of a nitrilase from Synechocystis sp. PCC6803 towards 3-isobutyl glutaronitrile (1 a). Exchange of these two residues resulted in the enantiopreference inversion (S, 90 % ee to R, 47 % ee). By further reshaping the substrate-binding pocket via routine site-saturation and combinatorial mutagenesis, variant E8 with higher activity and stereoselectivity (99 % ee, R) was obtained. The mutant enzyme was applied in the preparation of optically pure (R)-3-isobutyl-4-cyanobutanoic acid ((R)-2 a) and showed similar stereopreference inversion towards a series of 3-substituted glutaronitriles. This study may offer a general strategy to switch the stereopreference of other nitrilases and other enzymes toward the desymmetric reactions of prochiral substrates with two identical reactive functional groups.

2,3-Dihydroxybenzoic Acid Decarboxylase from Fusarium oxysporum: Crystal Structures and Substrate Recognition Mechanism.

A 2,3-dihydroxybenzoic acid decarboxylase from Fusarium oxysporum (2,3-DHBD_Fo) has a relatively high catalytic efficiency for the decarboxylation of 2,3-dihydroxybenzoic acid (DHBA) and carboxylation of catechol, thus it has a different substrate spectrum from other benzoic acid decarboxylases. We have determined the structures of 2,3-DHBD_Fo in its apo form and complexes with catechol or 2,5-dihydroxybenzoic acid at 1.55, 1.97, and 2.45 Šresolution, respectively. The crystal structures of 2,3-DHBD_Fo show that the enzyme exists as a homotetramer, and each active center has a Zn2+ ion coordinated by E8, H167, D291 and three water molecules. This is different from 2,6-DHBD from Rhizobium sporomusa, in which the Zn2+ ion is also coordinated with H10. Surprisingly, mutation of A10 of 2,3-DHBD_Fo to His resulted in almost complete loss of the enzyme activity. Enzyme-substrate docking and site-directed mutation studies indicate that residue R233Δ interacts with the 3-hydroxy group of 2,3-DHBA, and plays an important role in substrate recognition for this enzyme, thus revealing the molecular basis 2,3-dihydroxybenzoic acid decarboxylase.

Compositional and drug-resistance profiling of pathogens in patients with severe acute pancreatitis: a retrospective study.

BACKGROUND: Infection is one of the important causes of death in patients with severe acute pancreatitis (SAP), but the bacterial spectrum and antibiotic resistance are constantly changing. Making good use of antibiotics and controlling multi-drug-resistant (MDR) bacterial infections are of vital importance in improving the cure rate of SAP. We conducted a retrospective study in the hope of providing references for antibiotic selection and control of drug-resistant bacteria. METHODS: Retrospective analysis was performed on the data of patients hospitalized in our hospital due to acute pancreatitis (AP) in the past 5 years. General data were classified and statistically analyzed. Subsequently, the bacterial spectrum characteristics and the data related to drug-resistant bacterial infection of 569 AP patients were analyzed. Finally, unconditional logistic regression analysis was conducted to analyze the risk factors of MDR infection. RESULTS: A total of 398 patients were enrolled in this study and the hospitalization data and associated results were analyzed. A total of 461 strains of pathogenic bacteria were detected, including 223 (48.4%) gram-negative bacterial strains, 190 (41.2%) gram-positive bacterial strains and 48 (10.4%) fungal strains. The detection rates of resistance in gram-negative and gram-positive bacterial strains were 48.0% (107/223) and 25.3% (48/190), respectively. There were significant differences between the MDR group and the non-MDR group for the factors of precautionary antibiotic use, kinds of antibiotics used, receipt of carbapenem, tracheal intubation, hemofiltration and number of hospitalization days in the intensive care unit. Unconditional logistic regression revealed 2 risk factors for MDR bacterial infection. CONCLUSIONS: Our results illustrate that gram-negative bacteria were the most common pathogens in SAP infection, and the proportion of gram-positive bacteria increased notably. The rate of antibiotic resistance was higher than previously reported. Unconditional logistic regression analysis showed that using more types of antibiotics and the number of hospitalization days in the ICU were the risk factors associated with MDR bacterial infection.

The effect of ursodeoxycholic acid on the relative expression of the lipid metabolism genes in mouse cholesterol gallstone models.

BACKGROUND: Many studies indicate that gallstone formation has genetic components. The abnormal expression of lipid-related genes could be the basis for particular forms of cholesterol gallstone disease. The aim of this study was to obtain insight into lipid metabolism disorder during cholesterol gallstone formation and to evaluate the effect of ursodeoxycholic acid (UDCA) on the improvement of bile lithogenicity and its potential influence on the transcription of lipid-related genes. METHODS: Gallstone-susceptible mouse models were induced by feeding with a lithogenic diet (LD) for 8 weeks. Bile and liver tissues were obtained from these mouse models after 0, 4 and 8 weeks. Bile lipids were measured enzymatically, and the cholesterol saturation index (CSI) was calculated to evaluate the bile lithogenicity by using Carey's critical tables. Real-time polymerase chain reaction (RT-PCR) was used to detect the mRNA expression levels of farnesoid X receptor (FXR), liver X receptor (LXR), adenosine triphosphate-binding cassette subfamily G member 5/8 (ABCG5/8), cholesterol 7-α hydroxylase (CYP7A1), oxysterol 7-α hydroxylase (CYP7B1), sterol 27-α hydroxylase (CYP27A1), peroxisome proliferator-activated receptor alpha (PPAR-α) and adenosine triphosphate-binding cassette subfamily B member 11 (ABCB11). RESULTS: The rate of gallstone formation was 100% in the 4-week group but only 30% in the UDCA-treated group. The UDCA-treated group had a significantly lower CSI compared with other groups. Of special note, the data on the effects of UDCA showed higher expression levels of ABCG8, ABCB11 and CYP27A1, as well as lower expression levels of LXR and PPAR-α, compared to the model control group. CONCLUSIONS: UDCA exhibits tremendously potent activity in restraining lipid accumulation, thus reversing the lithogenic effect and protecting hepatocytes from serious pathological damage. The abnormal expression of ABCG8, CYP7A1, CYP27A1, LXR and PPAR-α might lead to high lithogenicity of bile. These results are helpful in exploring new lipid metabolism pathways and potential targets for the treatment of cholesterol stones and for providing some basis for the study of the pathogenesis and genetic characteristics of cholelithiasis. Research on the mechanism of UDCA in improving lipid metabolism and bile lithogenicity may be helpful for clinical treatment and for reducing the incidence of gallstones.

Retrospective quality metrics review of stereotactic radiosurgery plans treating multiple targets using single-isocenter volumetric modulated arc therapy.

PURPOSE: To characterize key plan quality metrics in multi-target stereotactic radiosurgery (SRS) plans treated using single-isocenter volumetric modulated arc therapy (VMAT) in comparison to dynamic conformal arc (DCA) plans treating single target. To investigate the feasibility of quality improvement in VMAT planning based on previous planning knowledge. MATERIALS AND METHODS: 97 VMAT plans of multi-target and 156 DCA plans of single-target treated in 2017 at a single institution were reviewed. A total of 605 targets were treated with these SRS plans. The prescription dose was normalized to 20 Gy in all plans for this analysis. Two plan quality metrics, target conformity index (CI) and normal tissue volume receiving more than 12 Gy (V12Gy), were calculated for each target. The distribution of V12Gy per target was plotted as a function of the target volume. For multi-target VMAT plans, the number of targets being treated in the same plan and the distance between targets were calculated to evaluate their impact on V12Gy. VMAT plans that had a large deviation of V12Gy from the average level were re-optimized to determine the possibility of reducing the variation of V12Gy in VMAT planning. RESULTS: Conformity index of multi-target VMAT plans were lower than that of DCA plans while the mean values of 12 Gy were comparable. The V12Gy for a target in VMAT plan did not show apparent dependence on the total number of targets or the distance between targets. The distribution of V12Gy exhibited a larger variation in VMAT plans compared to DCA plans. Re-optimization of outlier plans reduced V12 Gy by 33.9% and resulted in the V12Gy distribution in VMAT plans more closely resembling that of DCA plans. CONCLUSION: The benchmark data on key plan quality metrics were established for single-isocenter multi-target SRS planning. It is feasible to use this knowledge to guide VMAT planning and reduce high V12Gy outliers.