Charting the solid-state NMR signals of polysaccharides: A database-driven roadmap.

Solid-state nuclear magnetic resonance (ssNMR) measurements of intact cell walls and cellular samples often generate spectra that are difficult to interpret due to the presence of many coexisting glycans and the structural polymorphism observed in native conditions. To overcome this analytical challenge, we present a statistical approach for analyzing carbohydrate signals using high-resolution ssNMR data indexed in a carbohydrate database. We generate simulated spectra to demonstrate the chemical shift dispersion and compare this with experimental data to facilitate the identification of important fungal and plant polysaccharides, such as chitin and glucans in fungi and cellulose, hemicellulose, and pectic polymers in plants. We also demonstrate that chemically distinct carbohydrates from different organisms may produce almost identical signals, highlighting the need for high-resolution spectra and validation of resonance assignments. Our study provides a means to differentiate the characteristic signals of major carbohydrates and allows us to summarize currently undetected polysaccharides in plants and fungi, which may inspire future investigations.

Effect of cross polarization radiofrequency phases on signal phase.

Utilizing phases of radio frequency (RF) pulses to manipulate spin dynamics is routine in NMR and MRI, leading to spectacular techniques like phase cycling. In a very different area, cross polarization (CP) also has a long history as part of a vast number of solid-state NMR pulse sequences. However, a detailed study devoted to the effect of CP RF phases on NMR signal, seems not to be readily available. From first principles, we arrive at a simple dependence of NMR signal on arbitrary CP RF phases, for static and MAS conditions, accompanied by experimental verification. In the process, the CP propagator emerges as a product of RF "pulses" and a period of "free precession", conforming to coherence transfer pathway theory. The theoretical expressions may lend confidence for dealing with CP blocks with tunable phases in pulse sequences.

CCMRD: a solid-state NMR database for complex carbohydrates.

Carbohydrates are essential to various life activities in living organisms and serve as the central component in many biomaterials. As an emerging technique with steadily improving resolution, solid-state Nuclear Magnetic Resonance (NMR) spectroscopy has the unique capability in revealing the polymorphic structure and heterogeneous dynamics of insoluble complex carbohydrates. Here, we report the first solid-state NMR database for complex carbohydrates, Complex Carbohydrates Magnetic Resonance Database (CCMRD). This database currently holds the chemical shift information of more than four hundred solid-state NMR compounds and expects rapid expansion. CCMRD provides open portals for data deposition and supports search options based on NMR chemical shifts, carbohydrate names, and compound classes. With the timely implementation, this platform will facilitate spectral analysis and structure determination of carbohydrates and promote software development to benefit the research community. The database is freely accessible at www.ccmrd.org.

N-doped carbon dots modified with the epithelial cell adhesion molecule antibody as an imaging agent for HepG2 cells using their ultra-sensitive response to Al3.

Carbon dots (CDs) are emerging as an ideal multifunctional materials due to their ease of preparation and excellent properties in medical imaging technology, environmental monitoring, chemical analysis and other fields. N-doped CDs modified with the epithelial cell adhesion molecule antibody (anti-EpCAM-NCDs) were synthesized in an ingenious and high-output approach. Due to the fluorescence enhancement effect of the introduced N atoms, the obtained anti-EpCAM-NCDs exhibited a strong green emission with an absolute quantum yield of up to 32.5%. Anti-EpCAM-NCDs have immunofluorescent properties and an active targeting function. The fluorescence effect and fluorescence quenching of anti-EpCAM-NCDs are used to image cells and detect Al3+, respectively. Experimental results show that this probe exhibited a wide linear response to Al3+over a concentration range of 0-100µM with a detection limit and quantification limit of 3 nM and 6 nM, respectively. Significantly, anti-EpCAM-NCDs, which have negligible cytotoxicity, excellent biocompatibility and high photostability, could be used for the intracellular imaging of HepG2 cells and the detection of Al3+in environmental and biological samples. As an efficient multifunctional material, anti-EpCAM-NCDs hold great promise for a number of applications in biological systems.

Synthesis of bifunctional carbon quantum dots for bioimaging and anti-inflammation.

Carbon quantum dots (CDs) have attracted increased attention in recent decades because of their various applications in biosensing, bioimaging and drug delivery. In the present study, we have synthesized bifunctional ibuprofen-based carbon quantum dots (ICDs) using a simple one-step microwave-assisted method, for simultaneous bioimaging and anti-inflammatory effects. The ICDs exhibited high stability, low toxicity, negligible cytotoxicity and good biocompatibility in water. In particular, the produced ICDs demonstrated a decent imaging ability and excellent anti-inflammatory effects in vivo, making them potentially useful in bioimaging and future clinical treatment. Our results demonstrated that ICDs show promise in applications such as multifunctional biomaterials, depending on the selection of carbon sources, which would provide important guidance for the future design of multifunctional CDs in the field of biomedicine.

Solid-state NMR of plant and fungal cell walls: A critical review.

The cell walls of plants and microbes are a central source for bio-renewable energy and the major targets of antibiotics and antifungal agents. It is highly challenging to determine the molecular structure of complex carbohydrates, protein and lignin, and their supramolecular assembly in intact cell walls. This article selectively highlights the recent breakthroughs that employ 13C/15N solid-state NMR techniques to elucidate the architecture of fungal cell walls in Aspergillus fumigatus and the primary and secondary cell walls in a large variety of plant species such as Arabidopsis, Brachypodium, maize, and spruce. Built upon these pioneering studies, we further summarize the underexplored aspects of fungal and plant cell walls. The new research opportunities introduced by innovative methods, such as the detection of proton and quadrupolar nuclei on ultrahigh-field magnets and under fast magic-angle spinning, paramagnetic probes, natural-abundance DNP, and software development, are also critically discussed.

A novel method for typing of cesarean scar pregnancy based on size of cesarean scar diverticulum and its significance in clinical decision-making.

AIM: There is currently no universally accepted method for typing of cesarean scar pregnancy (CSP) to guide the choice of treatment approach. We introduce a new method for typing CSP and investigate its clinical significance. METHOD: Clinical data of 198 patients with CSP were collected and analyzed. The patients were divided into three types according to the size of their cesarean scar diverticula (CSD), measured by magnetic resonance imaging: type I (size of CSD ≤40 mm), type II (40 mm < size of CSD ≤70 mm) and type III (size of CSD >70 mm). RESULTS: With increase in the type level, the risk of adverse events increased significantly (χ2 = 36.345, P = 0.000). There was a significant difference in the choice of the treatment approaches in various types of the patients (χ2 = 27.106, P = 0.000). With increase in the type level, the invasiveness level of the treatment approach increased significantly (R = 0.405, P = 0.000). Further analysis found two other factors that influenced treatment choice. CONCLUSION: Our study, for the first time, demonstrates the value of size of CSD in typing of CSP and, thereby supplements the CSP typing system with a novel quantitative indicator. This typing method is of significance for evaluation of risk of CSP and guiding the choice of treatment approach. This typing method, combined with the two features of cesarean scar thickness and lesions protruding outside the uterine contour, will improve the risk assessment of CSP and the rationale of treatment plan formulation for this condition.

An Effective Assisted Method Using Hysteroscopy Transmittance Test and a Foley Catheter to Repair Previous Cesarean Scar Defect by Laparoscopy.

STUDY OBJECTIVE: To introduce an effective assisted method using the hysteroscopy transmittance test and a Foley catheter to repair previous cesarean scar defect (PCSD) by laparoscopy. DESIGN: A step-by-step explanation of the surgery using video. SETTING: A university hospital. PATIENTS: A young woman with abnormal uterine bleeding. INTERVENTIONS: First, we inspected the pelvic cavity and detached the adhesion, opened the uterovesical peritoneal reflection, and pushed down the bladder. Then, the hysteroscopy transmittance test was used to confirm the site and the size of the PCSD. Next, a Foley catheter was inserted into the diverticulum through the cervical canal, and then we removed the diverticulum along the outer edge [1-4]. The myometrium and the serosal layer were sutured continuously with absorbable sutures. At this point, a second hysteroscopy transmittance test was performed to verify the repair effect. Finally, we placed antiadhesive film. MEASUREMENTS AND MAIN RESULTS: The location, size, and boundary of the PCSD can be exactly marked by this method. The operative time was 68 minutes, blood loss was 20mL, and no complications occurred. CONCLUSION: This surgical method has the following benefits: the resection of the diverticulum is complete, and the suture is exact; it is suitable for patients with a thin diverticulum wall, large diverticulum cavity, and a long duration of bleeding after menstruation; the hysteroscopy transmittance test was used to confirm the site of the PCSD and verify the repair effect; and the Foley catheter can marker the resection site, prevent gas leakage, and stop bleeding by local compression.

Surprising Hofmeister Effects on the Bending Vibration of Water.

The Hofmeister series, which originally described the specific ion effects on the solubility of macromolecules in aqueous solutions, has been a long-standing unsolved and exceptionally challenging mystery in chemistry. The complexity of specific ion effects has prevented a unified theory from emerging. Accumulating research has suggested that the interactions among ions, water and various solutes play roles. However, among these interactions, the binding between ions and solutes is receiving most of the attention, whereas the effects of ions on the hydrogen-bond structure in liquid water have been deemed to be negligible. In this study, attenuated-total-reflectance Fourier transform infrared spectroscopy is used to study the infrared spectra of salt solutions. The results show that the red- and blue-shifts of the water bending band are in excellent agreement with the characteristic Hofmeister series, which suggests that the ions' effects on water structure might be the key role in the Hofmeister phenomenon.

Single­cell RNA sequencing reveals heterogeneity in ovarian cancer and constructs a prognostic signature for prognostic prediction and immunotherapy.

BACKGROUND: Ovarian cancer (OC) is one of the cancers with a high incidence at present, which poses a severe threat to women's health. This study focused on identifying the heterogeneity among malignant epithelial cell OC and constructing an effective prognostic signature to predict prognosis and immunotherapy according to a multidisciplinary study. METHODS: The InterCNV algorithm was used to identify the heterogeneity of OC based on the scRNA-seq and bulk RNA-seq data. Six algorithms selected EMTscore. An effective prognostic signature was conducted using the COX and Least Absolute Shrinkage and Selection Operator (LASSO) regression algorithms. The texting datasets were used to assess the accuracy of the prognostic signature. We evaluated different immune characteristics and immunotherapy response differences among other risk groups. RESULTS: A prognostic signature including 14 genes was established. The patients in the high-risk group have poor survival outcomes. We also found that the patients in the low-risk group have higher immune cell infiltration, enrichment of immune checkpoints, and immunotherapy response, suggesting that the patients in the low-risk group may be more sensitive to immunotherapy. Finally, the laboratory test results showed that KREMEN2 was identified as a novel biomarker and therapeutic target for OC patients. CONCLUSIONS: Our study established a GRG signature consisting of 16 genes based on the scRNA-seq and bulk RNA-seq data, which provides a new perspective on the prediction of prognosis and treatment strategy for OC.

Polysaccharide assemblies in fungal and plant cell walls explored by solid-state NMR.

Structural analysis of macromolecular complexes within their natural cellular environment presents a significant challenge. Recent applications of solid-state NMR (ssNMR) techniques on living fungal cells and intact plant tissues have greatly enhanced our understanding of the structure of extracellular matrices. Here, we selectively highlight the most recent progress in this field. Specifically, we discuss how ssNMR can provide detailed insights into the chemical composition and conformational structure of pectin, and the consequential impact on polysaccharide interactions and cell wall organization. We elaborate on the use of ssNMR data to uncover the arrangement of the lignin-polysaccharide interface and the macrofibrillar structure in native plant stems or during degradation processes. We also comprehend the dynamic structure of fungal cell walls under various morphotypes and stress conditions. Finally, we assess how the combination of NMR with other techniques can enhance our capacity to address unresolved structural questions concerning these complex macromolecular assemblies.

Heterotypic Interactions between the 40- and 42-Residue Isoforms of ß-Amyloid Peptides on Lipid Bilayer Surfaces.

Co-aggregation involving different amyloidogenic sequences has been emphasized recently in the modified amyloid cascade hypothesis. Yet, molecular-level interactions between two predominant ß-amyloid peptide sequences, Aß40 and Aß42, in the fibrillation process in membrane-mimicked environments remain unclear. Here, we report biophysical evidence that demonstrates the molecular-level interactions between Aß40 and Aß42 at the membrane-associated conucleation stage using dynamic nuclear polarization-enhanced solid-state NMR spectroscopy. These residue-specific contacts are distinguished from those reported in mature fibrils formed by either Aß40 or Aß42. Meanwhile, site-specific interactions between Aß and lipid molecules and modulation of microsecond-time-scale lipid dynamics are observed, which may be responsible for the more rapid and significant membrane content leakage compared to that with Aß40 alone.

The efficacy and safety of angiogenesis inhibitors for recurrent ovarian cancer: a meta­analysis.

OBJECTIVE: To investigate the efficacy and safety of angiogenesis inhibitors in the treatment of recurrent ovarian cancer (OC). METHODS: Electronic databases including PubMed, Web of Science, and the Cochrane Library were searched to find eligible studies until August 10, 2021. The data on overall survival (OS), progression-free survival (PFS), and objective response rate (ORR) were pooled. Furthermore, grade ≥ 3 adverse events (AEs) were investigated. RESULTS: A total of 13 studies with 3953 patients were included. Compared with control group, angiogenesis inhibitors resulted in significant improvement in PFS (hazard ratio (HR) = 0.61, 95%CI, 0.54-0.69), OS (HR = 0.88, 95%CI, 0.81-0.95), and ORR (odds ratio (OR) = 2.15, 95% CI, 1.74-2.65). However, angiogenesis inhibitors were associated with a higher risk of grade ≥ 3 AEs (relative risk (RR), 1.20, 95% CI, 1.04-1.38). CONCLUSION: Angiogenesis inhibitors can improve ORR, PFS, and OS in patients with recurrent OC, but they can increase the incidence of AEs ≥ 3.

Exploring the value of cesarean section diverticulum area to predict the safety of hysteroscopic management for cesarean scar pregnancy patients.

OBJECTIVE: To study indicators predicting the safety of hysteroscopic management for cesarean scar pregnancy (CSP) patients. METHODS: This was a retrospective study, starting from June 1, 2020. The study included 141 CSP patients who underwent hysteroscopic surgery and met the requirements of gestational age ≤12 weeks, stable vital signs, and preoperative magnetic resonance imaging. Patients were divided into control group and testing group according to surgical outcomes. Preoperative indicators were compared between the two groups, including a novel indicator, cesarean section diverticulum (CSD) area. RESULTS: Univariate analysis identified five statistically significant (P < 0.05) factors associated with hysteroscopy failure including a large CSD area. Multifactor logistic regression analysis showed that the only statistically significant indicator of all five factors was the CSD area. The area under the receiver operating characteristics curve of CSD area was 0.848. Next, we determined three cut-off values for CSD area that can be used to predict the outcome of surgery: 138, 189, and 300 mm2 . CONCLUSION: For the first time, we found that CSD area could predict the safety of hysteroscopic management for CSP patients and might be helpful for clinical decision making. The findings need to be verified by further research.

Carbohydrate-aromatic interface and molecular architecture of lignocellulose.

Plant cell walls constitute the majority of lignocellulosic biomass and serve as a renewable resource of biomaterials and biofuel. Extensive interactions between polysaccharides and the aromatic polymer lignin make lignocellulose recalcitrant to enzymatic hydrolysis, but this polymer network remains poorly understood. Here we interrogate the nanoscale assembly of lignocellulosic components in plant stems using solid-state nuclear magnetic resonance and dynamic nuclear polarization approaches. We show that the extent of glycan-aromatic association increases sequentially across grasses, hardwoods, and softwoods. Lignin principally packs with the xylan in a non-flat conformation via non-covalent interactions and partially binds the junction of flat-ribbon xylan and cellulose surface as a secondary site. All molecules are homogeneously mixed in softwoods; this unique feature enables water retention even around the hydrophobic aromatics. These findings unveil the principles of polymer interactions underlying the heterogeneous architecture of lignocellulose, which may guide the rational design of more digestible plants and more efficient biomass-conversion pathways.

A 13C three-dimensional DQ-SQ-SQ correlation experiment for high-resolution analysis of complex carbohydrates using solid-state NMR.

Complex carbohydrates are the key components of the protective cell walls of microbial pathogens and the bioenergy reservoir in plants and algae. Structural characterization of these polymorphic molecules requires assistance from multidimensional 13C correlation approaches. To facilitate the analysis of carbohydrate structure using solid-state NMR, we present a three-dimensional (3D) 13C-13C-13C experiment that includes a double-quantum (DQ) dimension and is thus free of the cube's body diagonal. The enhanced resolution supports the unambiguous resonance assignment of many polysaccharides in plant and fungal cell walls using uniformly 13C-labeled cells of spruce and Aspergillus fumigatus. Long-range structural restraints were effectively obtained to revisit our understanding of the spatial organization of plant cellulose microfibrils. The method is widely applicable to the investigations of cellular carbohydrates and carbon-based biomaterials.

Significance of TP53 Mutational Status-Associated Signature in the Progression and Prognosis of Endometrial Carcinoma.

Background: TP53 mutations are associated with poor outcome for patients with endometrial carcinoma (EC). However, to date, there have been no studies focused on the construction of TP53 mutational status-associated signature in EC. In this study, we aim to conduct a TP53 mutation-associated prognostic gene signature for EC. Methods: Hence, we explored the mutational landscape of TP53 in patients with EC based on the simple nucleotide variation data downloaded from The Cancer Genome Atlas (TCGA) database. Differential expression analysis and least absolute shrinkage and selection operator (LASSO)-Cox analysis was used to establish TP53 mutation-associated prognostic gene signature. The overall survival rate between the high-risk and low-risk groups was compared by the Kaplan-Meier (K-M) method. Results: We found that the TP53 mutation was associated with poor outcome, older age, lower BMI, and higher grade and stage of EC in patients. A TP53 mutational status-associated signature was established based on transcriptome profiling data. Moreover, the patients in TCGA database were categorized into high- and low-risk groups. Kaplan-Meier (K-M) analysis indicated that the patients in the high-risk group have poor survival outcome. Furthermore, receiver operating characteristic (ROC) curves confirmed the robust prognostic prediction efficiency of the TP53 mutational status-associated signature. Finally, the prognostic ability was successfully verified in the other two datasets from cBioPortal database as well as in 60 clinical specimens. Univariate (hazard ratio (HR) = 1.041, 95%CI = 1.031-1.051, p < 0.001) and multivariate (hazard ratio (HR) = 1.029, 95%CI = 1.018-1.040, p < 0.001) Cox regression analyses indicated that the TP53 mutational status-associated signature could be used as an independent prognostic factor for EC patients. Conclusion: In summary, our research constructed a powerful TP53 mutational status-associated signature that could be a potential novel prognostic biomarker and therapeutic target for EC.

Current limitations of solid-state NMR in carbohydrate and cell wall research.

High-resolution investigation of cell wall materials has emerged as an important application of biomolecular solid-state NMR (ssNMR). Multidimensional correlation experiments have become a standard method for obtaining sufficient spectral resolution to determine the polymorphic structure of carbohydrates and address biochemical questions regarding the supramolecular organization of cell walls. Using plant cellulose and matrix polysaccharides as examples, we will review how the multifaceted complexity of polysaccharide structure is impeding the resonance assignment process and assess the available biochemical and spectroscopic approaches that could circumvent this barrier. We will emphasize the ineffectiveness of the current methods in reconciling the ever-growing dataset and deriving structural information. We will evaluate the protocols for achieving efficient and homogeneous hyperpolarization across the cell wall material using magic-angle spinning dynamic nuclear polarization (MAS-DNP). Critical questions regarding the line-broadening effects of cell wall molecules at cryogenic temperature and by paramagnetic biradicals will be considered. Finally, the MAS-DNP method will be placed into a broader context with other structural characterization techniques, such as cryo-electron microscopy, to advance ssNMR research in carbohydrate and cell wall biomaterials.

Lymph-Vascular Space Invasion in Patients with Stages IA2-IIA2 Cervical Cancer Treated with Laparoscopic versus Open Radical Hysterectomy.

OBJECTIVE: To explore the relationship between laparoscopic radical hysterectomy (LRH) and cervical cancer lymph-vascular space invasion (LVSI) by comparing the prevalence of LVSI in cervical cancer patients who underwent LRH versus open radical hysterectomy (ORH). METHODS: The study participants were 1087 cervical cancer patients (FIGO 2009 stages IA2-IIA2) with pathologically confirmed with or without LVSI who underwent radical hysterectomy at Shengjing Hospital of China Medical University from 2013 through 2018. The patients were divided according to the type of surgical procedure into an LRH group (n=148) and an ORH group (n=939). RESULTS: In the LRH group, 31.76% of patients (47/148) had LVSI-positive tumors compared to 33.23% of patients (312/939) in the ORH group; the difference was not significant (p=0.724). No between-group differences in LVSI prevalence according to lymph node metastasis, interstitial infiltration depth, differentiation degree, and parametrial infiltration were found. However, the number of LVSI-positive patients whose cervical cancer lesions >4 cm (stage I B2 and II A2) was significantly higher in the LRH group than in the ORH group (Odds Ratio [OR] 0.333, 95% confidence interval [CI] 0.157-0.706, p=0.005). The 3-Year disease-free survival (DFS) in the LRH group is lower than that in the ORH group (94.75% vs 97.27%), but there was no significance (P=0.187). Furthermore, the percentage of LVSI-positive tumors in patients with lymph node metastases was significantly higher than those without lymph node metastases (OR 2.897, 95% CI 2.129-3.942, p=0.000). The 3-Year DFS were 98.22% in the LVSI negative patients and 93.78% in the LVSI positive patients, the difference was significant (P=0.002). CONCLUSION: A higher risk of lymph node metastasis and a lower 3-Year DFS was found in the LVSI-positive patients. In case of LVSI, it would be dangerous to treat patient in laparoscopy, especially in case of cervical cancer lesions >4cm.