Noninvasive Diagnostic Technique for Nonalcoholic Fatty Liver Disease Based on Features of Tongue Images.

OBJECTIVE: To investigate a new noninvasive diagnostic model for nonalcoholic fatty liver disease (NAFLD) based on features of tongue images. METHODS: Healthy controls and volunteers confirmed to have NAFLD by liver ultrasound were recruited from China-Japan Friendship Hospital between September 2018 and May 2019, then the anthropometric indexes and sampled tongue images were measured. The tongue images were labeled by features, based on a brief protocol, without knowing any other clinical data, after a series of corrections and data cleaning. The algorithm was trained on images using labels and several anthropometric indexes for inputs, utilizing machine learning technology. Finally, a logistic regression algorithm and a decision tree model were constructed as 2 diagnostic models for NAFLD. RESULTS: A total of 720 subjects were enrolled in this study, including 432 patients with NAFLD and 288 healthy volunteers. Of them, 482 were randomly allocated into the training set and 238 into the validation set. The diagnostic model based on logistic regression exhibited excellent performance: in validation set, it achieved an accuracy of 86.98%, sensitivity of 91.43%, and specificity of 80.61%; with an area under the curve (AUC) of 0.93 [95% confidence interval (CI) 0.68-0.98]. The decision tree model achieved an accuracy of 81.09%, sensitivity of 91.43%, and specificity of 66.33%; with an AUC of 0.89 (95% CI 0.66-0.92) in validation set. CONCLUSIONS: The features of tongue images were associated with NAFLD. Both the 2 diagnostic models, which would be convenient, noninvasive, lightweight, rapid, and inexpensive technical references for early screening, can accurately distinguish NAFLD and are worth further study.

Highly Selective and Fast Response/Recovery Cataluminescence Sensor Based on SnO2 for H2S Detection.

In the present work, three kinds of nanosized SnO2 samples were successfully synthesized via a hydrothermal method with subsequent calcination at temperatures of 500 °C, 600 °C, and 700 °C. The morphology and structure of the as-prepared samples were characterized using X-ray diffraction, transmission electron microscopy, selected area electron diffraction, Brunauer-Emmett-Teller analysis, and X-ray photoelectron spectroscopy. The results clearly indicated that the SnO2 sample calcined at 600 °C had a higher amount of chemisorbed oxygen than the SnO2 samples calcined at 500 °C and 700 °C. Gas sensing investigations revealed that the cataluminescence (CTL) sensors based on the three SnO2 samples all exhibited high selectivity toward H2S, but the sensor based on SnO2-600 °C exhibited the highest response under the same conditions. At an operating temperature of 210 °C, the SnO2-600 °C sensor showed a good linear response to H2S in the concentration range of 20-420 ppm, with a detection limit of 8 ppm. The response and recovery times were 3.5 s/1.5 s for H2S gas within the linear range. The study on the sensing mechanism indicated that H2S was oxidized into excited states of SO2 by chemisorbed oxygen on the SnO2 surface, which was mainly responsible for CTL emission. The chemisorbed oxygen played an important role in the oxidation of H2S, and, as such, the reason for the SnO2-600 °C sensor showing the highest response could be ascribed to the highest amount of chemisorbed oxygen on its surface. The proposed SnO2-based gas sensor has great potential for the rapid monitoring of H2S.

Prevalence and risk factors of osteoporosis detected by dual-energy X-ray absorptiometry among Chinese patients with primary biliary cholangitis.

BACKGROUND: Osteoporosis is an extrahepatic complication of primary biliary cholangitis (PBC) that increases the risk of fractures and mortality. However, Epidemiological studies of osteoporosis in patients with PBC in China and the Asia-Pacific region is lack. AIM: To assess the prevalence and clinical characteristics of osteoporosis in Chinese patients with PBC. METHODS: This retrospective analysis included consecutive patients with PBC from a tertiary care center in China who underwent bone mineral density (BMD) assessment using dual-energy X-ray absorptiometry between January 2013 and December 2021. We defined subjects with T-scores ≤ -2.5 in any sites (L1 to L4, femoral neck, or total hip) as having osteoporosis. Demographic, serological, clinical, and histological data were collected. Independent risk factors for osteoporosis were identified by multivariate logistic regression analysis. RESULTS: A total of 268 patients with PBC [236 women (88.1%); mean age, 56.7 ± 10.6 years; 163 liver biopsies (60.8%)] were included. The overall prevalence of osteoporosis in patients with PBC was 45.5% (122/268), with the prevalence of osteoporosis in women and men being 47.0% and 34.4%, respectively. The prevalence of osteoporosis in postmenopausal women was significantly higher than that in premenopausal women (56.3% vs 21.0%, P < 0.001). Osteoporosis in patients with PBC is associated with age, fatigue, menopausal status, previous steroid therapy, body mass index (BMI), splenomegaly, gastroesophageal varices, ascites, Mayo risk score, histological stage, alanine aminotransferase, albumin, bilirubin, platelet and prothrombin activity. Multivariate regression analysis identified that older age, lower BMI, previous steroid therapy, higher Mayo risk score, and advanced histological stage as the main independent risk factors for osteoporosis in PBC. CONCLUSION: Osteoporosis is very common in Chinese patients with PBC, allowing for prior screening of BMD in those PBC patients with older age, lower BMI, previous steroid therapy and advanced liver disease.

Effective assessment of lanthanide ion delivery into live cells by paramagnetic NMR spectroscopy.

We report an effective assessment of lanthanide ion (Ln3+) delivery into live cells by paramagnetic NMR spectroscopy. Free Ln3+ ions are toxic to live cells resulting in a gradual leakage of target proteins to the extracellular media. The citrate-Ln3+ complex is an efficient and mild reagent over the free Ln3+ form for live cell delivery.

Development and validation of machine learning models for nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) had become the most prevalent liver disease worldwide. Early diagnosis could effectively reduce NAFLD-related morbidity and mortality. This study aimed to combine the risk factors to develop and validate a novel model for predicting NAFLD. METHODS: We enrolled 578 participants completing abdominal ultrasound into the training set. The least absolute shrinkage and selection operator (LASSO) regression combined with random forest (RF) was conducted to screen significant predictors for NAFLD risk. Five machine learning models including logistic regression (LR), RF, extreme gradient boosting (XGBoost), gradient boosting machine (GBM), and support vector machine (SVM) were developed. To further improve model performance, we conducted hyperparameter tuning with train function in Python package 'sklearn'. We included 131 participants completing magnetic resonance imaging into the testing set for external validation. RESULTS: There were 329 participants with NAFLD and 249 without in the training set, while 96 with NAFLD and 35 without were in the testing set. Visceral adiposity index, abdominal circumference, body mass index, alanine aminotransferase (ALT), ALT/AST (aspartate aminotransferase), age, high-density lipoprotein cholesterol (HDL-C) and elevated triglyceride (TG) were important predictors for NAFLD risk. The area under curve (AUC) of LR, RF, XGBoost, GBM, SVM were 0.915 [95% confidence interval (CI): 0.886-0.937], 0.907 (95% CI: 0.856-0.938), 0.928 (95% CI: 0.873-0.944), 0.924 (95% CI: 0.875-0.939), and 0.900 (95% CI: 0.883-0.913), respectively. XGBoost model presented the best predictive performance, and its AUC was enhanced to 0.938 (95% CI: 0.870-0.950) with further parameter tuning. CONCLUSIONS: This study developed and validated five novel machine learning models for NAFLD prediction, among which XGBoost presented the best performance and was considered a reliable reference for early identification of high-risk patients with NAFLD in clinical practice.

Stereospecific recognition of a chiral centre over multiple flexible covalent bonds by 19F-NMR.

High performance in chiral recognition by a reactive 19F-tag was demonstrated for a variety of enantiomers. The analytes with up to five flexible covalent bonds from the chiral center can be discriminated by a sensitive chiral reporter manifested in the 19F-NMR spectrum. Simultaneous identification of chiral amines in a mixture and high accuracy ee determination were achieved.

Atherogenic index of plasma combined with waist circumference and body mass index to predict metabolic-associated fatty liver disease.

BACKGROUND: Early identification of metabolic-associated fatty liver disease (MAFLD) is urgent. Atherogenic index of plasma (AIP) is a reference predictor of obesity-related diseases, but its predictive value for MAFLD remains unclear. No studies have reported whether its combination with waist circumference (WC) and body mass index (BMI) can improve the predictive performance for MAFLD. AIM: To systematically explore the relationship between AIP and MAFLD and evaluate its predictive value for MAFLD and to pioneer a novel noninvasive predictive model combining AIP, WC, and BMI while validating its predictive performance for MAFLD. METHODS: This cross-sectional study consecutively enrolled 864 participants. Multivariate logistic regression analysis and receiver operating characteristic curve were used to evaluate the relationship between AIP and MAFLD and its predictive power for MAFLD. The novel prediction model A-W-B combining AIP, WC, and BMI to predict MAFLD was established, and internal verification was completed by magnetic resonance imaging diagnosis. RESULTS: Subjects with higher AIP exhibited a significantly increased risk of MAFLD, with an odds ratio of 12.420 (6.008-25.675) for AIP after adjusting for various confounding factors. The area under receiver operating characteristic curve of the A-W-B model was 0.833 (0.807-0.858), which was significantly higher than that of AIP, WC, and BMI (all P < 0.05). Subgroup analysis illustrated that the A-W-B model had significantly higher area under receiver operating characteristic curves in female, young and nonobese subgroups (all P < 0.05). The best cutoff values for the A-W-B model to predict MAFLD in males and females were 0.5932 and 0.4105, respectively. Additionally, in the validation set, the area under receiver operating characteristic curve of the A-W-B model to predict MAFLD was 0.862 (0.791-0.916). The A-W-B level was strongly and positively associated with the liver proton density fat fraction (r = 0.630, P < 0.001) and significantly increased with the severity of MAFLD (P < 0.05). CONCLUSION: AIP was strongly and positively associated with the risk of MAFLD and can be a reference predictor for MAFLD. The novel prediction model A-W-B combining AIP, WC, and BMI can significantly improve the predictive ability of MAFLD and provide better services for clinical prediction and screening of MAFLD.

Distinct stereospecific effect of chiral tether between a tag and protein on the rigidity of paramagnetic tag.

Flexibility between the paramagnetic tag and its protein conjugates is a common yet unresolved issue in the applications of paramagnetic NMR spectroscopy in biological systems. The flexibility greatly attenuates the magnetic anisotropy and compromises paramagnetic effects especially for pseudocontact shift and residual dipolar couplings. Great efforts have been made to improve the rigidity of paramagnetic tag in the protein conjugates, however, the effect of local environment vicinal to the protein ligation site on the paramagnetic effects remains poorly understood. In the present work, the stereospecific effect of chiral tether between the protein and a tag on the paramagnetic effects produced by the tag attached via a D- and L-type linker between the protein and paramagnetic metal chelating moiety was assessed. The remarkable chiral effect of the D- and L-type tether between the tag and the protein on the rigidity of paramagnetic tag is disclosed in a number of protein-tag-Ln complexes. The chiral tether formed between the D-type tag and L-type protein surface minimizes the effect of the local environment surrounding the ligation site on the averaging of paramagnetic tag, which is helpful to preserve the rigidity of a paramagnetic tag in the protein conjugates.

Efficient Protein-Protein Couplings Mediated by Small Molecules under Mild Conditions.

Protein-protein coupling reactions under physiological conditions that do not impact the three-dimensional structures of the proteins are in high demand. Owing to the combination of phenylsulfonyl and aldehyde groups in 5-fluoro-4-(phenylsulfonyl)picolinaldehyde (FPPA), the fluorine substituent shows high reactivity toward free thiols. In FPPA, the fluorine is more reactive than phenylsulfonyl for free thiols. Thus the first quantitative nucleophilic substitution can be followed by selective substitution of phenylsulfonyl by an additional thiol or cyclization of aldehyde with a 1,2-aminothiol molecule. The FPPA mediated protein-protein coupling proceeds efficiently under mild conditions, resulting in stable protein conjugates. This coupling method has negligible 3D structural perturbations on the target proteins, and it produces overall intact, nearly traceless, and native structural folds of proteins. It is highly suitable for reconstruction of proteins that are difficult to make and segmental isotopic labeling of multidomain proteins.

Simultaneous Discrimination and Quantification of Enantiomeric Amino Acids under Physiological Conditions by Chiral 19F NMR Tag.

Enantiomeric analysis is of great significance in chemistry, chemical biology and pharmaceutical research. We herein propose a chiral 19F NMR tag containing an amino reactive NHS group to discriminate the enantiomeric amino acids under physiological conditions by NMR spectroscopy. The chiral 19F NMR tag readily forms stable amide products with the amino acids in aqueous solution. The stereospecific chemistry of enantiomeric amino acids is discriminated by a stereogenic carbon bonded with a 19F atom and is therefore decoded by the 19F reporter and manifested in the distinct 19F chemical shift. The chemical shift difference (ΔΔδ) of the chiral 19F NMR tag derived enantiomeric amino acids variants has a broad chemical shift range between -1.13 to 1.68 ppm, indicating the high sensitivity of the chiral 19F NMR tag to the stereospecific environment surrounding the individual amino acids. The distinguishable chemical shift produced by the chiral 19F NMR tag permits simultaneous discrimination and quantification of the enantiomeric amino acids in a mixture. The high fidelity of the chiral 19F NMR tag affords high-accuracy determination of the enantiomeric composition of amino acids by simple 1D NMR under physiological conditions.

Simultaneous Quantification of Biothiols and Deciphering Diverse GSH Stability in Different Live Cells by 19F-Tag.

GSH, Cys, Hcy, and H2S are important biothiols and play important roles in the living systems. Quantitative and simultaneous determination of these biothiols under physiological conditions is still a challenge. Herein, we developed an effective 19F-reactive tag that readily interacts with these four biothiols for the generation of stable thioether products that have distinguishable 19F-chemical shifts. These thioester compounds encode the characteristic fingerprint profiles of each biothiols, allowing one to simultaneously quantify and determine these biothiols by 1D 19F NMR spectroscopy. The intra-/extracellular GSH in live cells was assessed by the established strategy, and remarkable variations in the GSH stability were determined between the normal mammalian cells and cancer cells. It is notable that GSH hydrolyzes efficiently in the out-membrane of the cancer cells and the lysates. In contrast, GSH remains stable in the tested normal cells.

Simultaneous identification and quantification of amino acids in biofluids by reactive 19F-tags.

A robust method to identify and quantify amino acids close to physiological conditions by 1D 19F NMR was established. Each 19F-derivatized amino acid has its characteristic chemical-shift profile that is readily identified in the mixture of amino acids or in biofluids including fetal bovine serum and cell lysates. The method shows great potential in metabolomics and biochemical analysis.

Rigid, Highly Reactive and Stable DOTA-like Tags Containing a Thiol-Specific Phenylsulfonyl Pyridine Moiety for Protein Modification and NMR Analysis*.

Site specific installation of a paramagnetic ion with magnetic anisotropy in a biomolecule generates valuable structural restraints, such as pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs). These paramagnetic effects can be used to characterize the structures, interactions and dynamics of biological macromolecules and their complexes. Two single-armed DOTA-like tags, BrPSPy-DO3M(S)A-Ln and BrPSPy-6M-DO3M(S)A-Ln, each containing a thiol-specific reacting group, that is, a phenylsulfonyl pyridine moiety, are demonstrated as rigid, reactive and stable paramagnetic tags for protein modification by formation of a reducing resistant thioether bond between the protein and the tag. The two tags present high reactivity with the solvent exposed thiol group in aqueous solution at room temperature. The introduction of Br at the meta-position in pyridine enhances the reactivity of 4-phenylsulfonyl pyridine towards the solvent exposed thiol group in a protein, whereas the ortho-methyl group in pyridine increases the rigidity of the tag in the protein conjugates. The high performance of these two tags has been demonstrated in different cysteine mutants of ubiquitin and GB1. The high reactivity and rigidity of these two tags can be added in the toolbox of paramagnetic tags suitable for the high-resolution NMR measurements of biological macromolecules and their complexes.

Nanoporous NiSb to Enhance Nitrogen Electroreduction via Tailoring Competitive Adsorption Sites.

Ambient nitrogen reduction reaction (NRR) is attracting extensive interest but still suffers from sluggish kinetics owing to competitive rapid hydrogen evolution and difficult nitrogen activation. Herein, nanoporous NiSb alloy is reported as an efficient electrocatalyst for N2 fixation, achieving a high ammonia yield rate of 56.9 µg h-1 mg-1 with a Faradaic efficiency of 48.0%. Density functional theory calculations reveal that in NiSb alloy, Ni favors N2 hydrogenation while the neighboring Sb separates active sites for proton and N2 adsorption, which optimizes the adsorption/desorption of intermediates and enables an energetically favorable NRR pathway. This work indicates promising electrocatalytic application of the alloys of 3d and p block metals toward the NRR and provides an intriguing strategy to enhance the reduction of inert molecules by restraining the competitive hydrogen adsorption.

Assessing multiple conformations of lanthanide binding tags for proteins using a sensitive 19F-reporter.

Quantifying the isomeric species of metal complexes in solution is difficult. 19F NMR herein was used to determine the abundance of isomeric species and dynamic properties of lanthanide binding tags. The results suggest that 19F is an efficient reporter in assessing and screening paramagnetic tags suitable for protein NMR analysis.

Chronic Oral Administration of Magnesium-L-Threonate Prevents Oxaliplatin-Induced Memory and Emotional Deficits by Normalization of TNF-α/NF-κB Signaling in Rats.

Antineoplastic drugs such as oxaliplatin (OXA) often induce memory and emotional deficits. At present, the mechanisms underlying these side-effects are not fully understood, and no effective treatment is available. Here, we show that the short-term memory deficits and anxiety-like and depression-like behaviors induced by intraperitoneal injections of OXA (4 mg/kg per day for 5 consecutive days) were accompanied by synaptic dysfunction and downregulation of the NR2B subunit of N-methyl-D-aspartate receptors in the hippocampus, which is critically involved in memory and emotion. The OXA-induced behavioral and synaptic changes were prevented by chronic oral administration of magnesium-L-threonate (L-TAMS, 604 mg/kg per day, from 2 days before until the end of experiments). We found that OXA injections significantly reduced the free Mg2+ in serum and cerebrospinal fluid (from ~ 0.8 mmol/L to ~ 0.6 mmol/L). The Mg2+ deficiency (0.6 mmol/L) upregulated tumor necrosis factor (TNF-α) and phospho-p65 (p-p65), an active form of nuclear factor-kappaB (NF-κB), and downregulated the NR2B subunit in cultured hippocampal slices. Oral L-TAMS prevented the OXA-induced upregulation of TNF-α and p-p65, as well as microglial activation in the hippocampus and the medial prefrontal cortex. Finally, similar to oral L-TAMS, intracerebroventricular injection of PDTC, an NF-κB inhibitor, also prevented the OXA-induced memory/emotional deficits and the changes in TNF-α, p-p65, and microglia. Taken together, the activation of TNF-α/NF-κB signaling resulting from reduced brain Mg2+ is responsible for the memory/emotional deficits induced by OXA. Chronic oral L-TAMS may be a novel approach to treating chemotherapy-induced memory/emotional deficits.

Dynamic Exchange of the Metal Chelating Moiety: A Key Factor in Determining the Rigidity of Protein-Tag Conjugates in Paramagnetic NMR.

Site-specific labeling of proteins with a paramagnetic tag is an efficient way to provide atomic-resolution information about the dynamics, interactions, and structures of the proteins and protein-ligand complexes. The paramagnetic effects manifested in NMR spectroscopy generally contain paramagnetic relaxation enhancement, pseudocontact shifts (PCSs), and residual dipolar coupling (RDC), and these effects correlate closely with the flexibility of protein-tag conjugates. The rigidity of the paramagnetic tag is greatly important in decoding the structural details of macromolecular complexes, because paramagnetic averaging reduces the PCSs and RDCs. Here we show that the dynamic exchange of the metal chelating moiety is a key factor in determining the rigidity of the paramagnetic tag in the protein conjugates. Decreasing the conformational exchange rates in the metal chelating moiety greatly minimizes the paramagnetic averaging and thus increases PCSs and RDCs. This effect has been demonstrated in an open-chain tag, Py-l-Cys-DTPA, which generates large PCSs and RDCs that are comparable to those of the reported cyclic DOTA-like tags. The proposed route offers a unique way to design suitable paramagnetic tags for applications in biological systems.

Normalization of magnesium deficiency attenuated mechanical allodynia, depressive-like behaviors, and memory deficits associated with cyclophosphamide-induced cystitis by inhibiting TNF-α/NF-κB signaling in female rats.

BACKGROUND: Bladder-related pain symptoms in patients with bladder pain syndrome/interstitial cystitis (BPS/IC) are often accompanied by depression and memory deficits. Magnesium deficiency contributes to neuroinflammation and is associated with pain, depression, and memory deficits. Neuroinflammation is involved in the mechanical allodynia of cyclophosphamide (CYP)-induced cystitis. Magnesium-L-Threonate (L-TAMS) supplementation can attenuate neuroinflammation. This study aimed to determine whether and how L-TAMS influences mechanical allodynia and accompanying depressive symptoms and memory deficits in CYP-induced cystitis. METHODS: Injection of CYP (50 mg/kg, intraperitoneally, every 3 days for 3 doses) was used to establish a rat model of BPS/IC. L-TAMS was administered in drinking water (604 mg·kg-1·day-1). Mechanical allodynia in the lower abdomen was assessed with von Frey filaments using the up-down method. Forced swim test (FST) and sucrose preference test (SPT) were used to measure depressive-like behaviors. Novel object recognition test (NORT) was used to detect short-term memory function. Concentrations of Mg2+ in serum and cerebrospinal fluid (CSF) were measured by calmagite chronometry. Western blot and immunofluorescence staining measured the expression of tumor necrosis factor-α/nuclear factor-κB (TNF-α/NF-κB), interleukin-1ß (IL-1ß), and N-methyl-D-aspartate receptor type 2B subunit (NR2B) of the N-methyl-D-aspartate receptor in the L6-S1 spinal dorsal horn (SDH) and hippocampus. RESULTS: Free Mg2+ was reduced in the serum and CSF of the CYP-induced cystitis rats on days 8, 12, and 20 after the first CYP injection. Magnesium deficiency in the serum and CSF correlated with the mechanical withdrawal threshold, depressive-like behaviors, and short-term memory deficits (STMD). Oral application of L-TAMS prevented magnesium deficiency and attenuated mechanical allodynia (n = 14) and normalized depressive-like behaviors (n = 10) and STMD (n = 10). The upregulation of TNF-α/NF-κB signaling and IL-1ß in the L6-S1 SDH or hippocampus was reversed by L-TAMS. The change in NR2B expression in the SDH and hippocampus in the cystitis model was normalized by L-TAMS. CONCLUSIONS: Normalization of magnesium deficiency by L-TAMS attenuated mechanical allodynia, depressive-like behaviors, and STMD in the CYP-induced cystitis model via inhibition of TNF-α/NF-κВ signaling and normalization of NR2B expression. Our study provides evidence that L-TAMS may have therapeutic value for treating pain and comorbid depression or memory deficits in BPS/IC patients.