Efficient optical plasmonic tweezer-controlled single-molecule SERS characterization of pH-dependent amylin species in aqueous milieus.

It is challenging to characterize single or a few biomolecules in physiological milieus without excluding the influences of surrounding environment. Here we utilize optical plasmonic trapping to construct a dynamic nanocavity, which reduces the diffraction-limited detection volume and provides reproducible electromagnetic field enhancements to achieve high-throughput single-molecule surface-enhanced Raman spectroscopy (SERS) characterizations in aqueous environments. Specifically, we study human Islet Amyloid Polypeptide (amylin, hIAPP) under different physiological pH conditions by combining spectroscopic experiments and molecular dynamics (MD) simulations. Based on a statistically significant amount of time-dependent SERS spectra, two types of low-populated transient species of hIAPP containing either turn or ß-sheet structure among its predominant helix-coil monomers are characterized during the early-stage incubation at neutral condition, which play a crucial role in driving irreversible amyloid fibril developments even after a subsequent adjustment of pH to continue the prolonged incubation at acidic condition. Our results might provide profound mechanistic insight into the pH-regulated amyloidogenesis and introduce an alternative approach for investigating complex biological processes at the single-molecule level.

Preparation of lithium-containing magnesium phosphate-based composite ceramics having high compressive strength, osteostimulation and proangiogenic effects.

Fairly high concentrations of magnesium and lithium are conducive to improving the osteogenic and angiogenic capacities. In the current study, lithium-containing magnesium phosphate-based ceramics (AMP/LMPGs) were prepared from amorphous magnesium phosphate (AMP) at a low sintering temperature (650 °C), and the lithium/magnesium-containing phosphate glasses (LMPGs) were utilized as sintering additives. During the sintering procedure of AMP/LMPGs, the AMP reacted with LMPGs, producing new compounds. The AMP/LMPGs displayed nano-size grains and plentiful micropores. The addition of LMPGs noticeably increased the porosity as well as compressive strength of the AMP/LMPGs ceramics. The AMP/LMPGs sustainedly released Mg, P and Li ions, forming Mg-rich ionic microenvironment, which ameliorated cellular proliferation, osteogenic differentiation and proangiogenic capacities. The AMP/LMPGs ceramics with considerably high compressive strength, osteostimulation and proangiogenic effects were expected to efficiently regenerate the bone defects.

Potential clinical feasibility of synthetic MRI in bladder tumors: a comparative study with conventional MRI.

Background: Synthetic magnetic resonance imaging (MRI) can provide quantitative information about inherent tissue properties and synthesize tailored contrast-weighted images simultaneously in a single scan. This study aimed to investigate the clinical feasibility of synthetic MRI in bladder tumors. Methods: A total of 47 patients (37 males; mean age: 66±10 years old) with postoperative pathology-confirmed papillary urothelial neoplasms of the bladder were enrolled in this retrospective study. A 2-dimensional (2D) multi-dynamic multi-echo pulse sequence was performed for synthetic MRI at 3T. The overall image quality, lesion conspicuity, contrast resolution, resolution of subtle anatomic structures, motion artifact, blurring, and graininess of images were subjectively evaluated by 2 radiologists independently using a 5-point Likert scale for qualitative analysis. The signal intensity ratio (SIR), signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured for quantitative analysis. Linear weighted Kappa, Wilcoxon's signed-rank test, and the Mann-Whitney U-test were used for statistical analysis. Results: The interobserver consistency was excellent (κ values: 0.607-1). Synthetic T1-weighted (syn-T1w) and synthetic T2-weighted (syn-T2w) images obtained scores of 4 in most subjective terms, which were relatively smaller than those of conventional images. The SIR and SNR of syn-T1w were significantly higher than those of con-T1w images (SIR 2.37±0.86 vs. 1.47±0.20, P<0.001; SNR 21.83±9.43 vs. 14.81±3.30, P<0.001). No difference was found in SIR between syn-T2w and conventional T2-weighted (con-T2w) images, whereas the SNR of the syn-T2w was significantly lower (8.79±4.06 vs. 26.49±6.80, P<0.001). Additionally, the CNR of synthetic images was significantly lower than that of conventional images (T1w 1.41±0.72 vs. 2.68±1.04; T2w 1.40±0.87 vs. 4.03±1.55, all P<0.001). Conclusions: Synthetic MRI generates morphologic magnetic resonance (MR) images with diagnostically acceptable image quality in bladder tumors, especially T1-weighted images with high image contrast of tumors relative to urine. Further technological improvements are needed for synthetic MRI to reduce noise. Combined with T1, T2, and proton density (PD) quantitative data, synthetic MRI has potential for clinical application in bladder tumors.

BNIP3 as a potential biomarker for the identification of prognosis and diagnosis in solid tumours.

BACKGROUND: Traditional radiotherapy and chemotherapy have been intensively studied for their role in the treatment of tumours. However, these therapies often cause side effects for patients, which calls for the development of novel treatment options for tumours. B-cell lymphoma-2 (Bcl-2)/adenovirus E1B 19 kDa-interacting protein 3 (BNIP3) reportedly apoptosis-inducing effects in tumour cells and is associated with the progression and treatment of multiple tumours. Nevertheless, little is known about its potential role in tumour diagnosis and targeted therapy. FINDINGS: The results of the study demonstrated that the interaction of BNIP3 with HDAC1 may affect the progression of breast invasive cancer (BRCA), sarcoma (SARC), kidney renal clear cell carcinoma (KIRC), and low-grade glioma (LGG). BNIP3 seemed to exert its effects in BRCA and SARC primarily through gene silencing and integrator complex, and in KIRC and LGG, mainly by affecting olfactory function, suggesting that targeted therapy can be developed based on the above signalling pathway and downstream molecules. INTERPRETATION: BNIP3 has emerged as a promising therapeutic and diagnostic target for BRCA, SARC, KIRC, and LGG, providing new insights into tumour molecular therapies in the clinic.

Fabrication of 3D printed Ca3Mg3(PO4)4-based bioceramic scaffolds with tailorable high mechanical strength and osteostimulation effect.

Calcium, magnesium and phosphate are predominant constituents in the human bone. In this study, magnesium-calcium phosphate composite bioceramic scaffolds were fabricated utilizing Mg3(PO4)2 and ß-Ca3(PO4)2 as starting materials, and their pore structure was constructed by 3D printing. The porosity and compressive strength of the composite bioceramic scaffolds could be adjusted by altering the sintering temperature and the formula of starting materials. The composite bioceramic scaffolds prepared from 60 wt% Mg3(PO4)2 and 40 wt% ß-Ca3(PO4)2 were dominated by the Ca3Mg3(PO4)4 phase, and this Ca3Mg3(PO4)4-based bioceramic scaffolds possessed the highest compressive strength (12.7 - 92.4 MPa). Moreover, the Ca3Mg3(PO4)4-based bioceramic scaffolds stimulated cellular growth and osteoblastic differentiation of bone marrow stromal cells. The Ca3Mg3(PO4)4-based bioceramic scaffolds as bone regenerative biomaterials are flexible to the requirement of bone defects at various sites.

Improving the osseointegration and soft tissue sealing of zirconia ceramics by the incorporation of akermanite via sol infiltration for dental implants.

Zirconia ceramics are promising dental implant materials due to their high-grade biocompatibility, high mechanical strength, and distinctive aesthetic appearance. Nevertheless, zirconia ceramics are bio-inert with a lack of osseointegration and soft tissue sealing, which limits dental implant applications. As such, the fabrication of zirconia ceramics with high mechanical strength, excellent osseointegration and soft tissue sealing performance remains a great challenge in the dental restoration field. In this article, a novel zirconia ceramic with akermanite (AKT) modification by the negative pressure infiltration method is presented. The effects of AKT sol infiltration at different times on the morphology, phase composition, mechanical properties, bioactivity, osseointegration and soft tissue sealing of the modified zirconia ceramics have been systematically investigated. The modified zirconia ceramics feature excellent mechanical properties and significantly improved surface roughness, hydrophilia, and apatite mineralization ability as compared with unmodified zirconia ceramics. Furthermore, cell-culture experiment results indicated that the surface modification of zirconia ceramics could promote adhesion, spreading, migration, proliferation and osteogenic differentiation of mouse bone marrow stromal stem cells (mBMSCs), as well as the early adhesion, spreading, proliferation and fibroblast differentiation of human gingival fibroblasts (HGFs) in vitro. The prepared bioactive zirconia distinctively enhanced the alkaline phosphate (ALP) activity, osteogenesis-related gene expression of mBMSCs and fibroblast-related-gene expression of HGFs. The in vivo evaluation confirmed that 15-TZP ceramics could promote bone-implant osseointegration to the greatest extent as compared with pure zirconia ceramics. To conclude, our research has shown that AKT-modified zirconia ceramics can achieve bone integration and soft tissue sealing, indicating that they have a lot of potential for application as a novel dental implant material in the clinical setting.

Can decreased cost-sharing reduce the vulnerability of sick families to poverty? An analysis of the multi-level social health insurance scheme in China.

In recent years, China has been increasing social health insurance benefits to alleviate poverty due to illness. In 2015, China introduced the Critical Illness Insurance for patients with high out-of-pocket expenses as supplementary to the social health insurance, which categorized patients with different medical expenses into different cost-sharing policies. We conducted a survey on households with high-cost patients in rural Shandong in 2019 and employed the instrumental variables estimation approach to determine how different cost-sharing measures affect households' poverty vulnerability. We found that cost-sharing reduction significantly decreases the vulnerability of sick families to poverty. Moreover, we found that the positive effect is attributed to a reduction in health burden and household livelihood capital shocks. The vulnerability to poverty is still exceptionally high owing to the heavy health burden in rural China and other developing countries. The results of our study provide insights into poverty alleviation by improving social health insurance in developing economies.

Genome-wide identification of resistance genes and transcriptome regulation in yeast to accommodate ammonium toxicity.

BACKGROUND: Ammonium is an important raw material for biomolecules and life activities, and the toxicity of ammonium is also an important ecological and agricultural issue. Ammonium toxicity in yeast has only recently been discovered, and information on its mechanism is limited. In recent years, environmental pollution caused by nitrogen-containing wastewater has been increasing. In addition, the use of yeast in bioreactors to produce nitrogen-containing compounds has been developed. Therefore, research on resistance mechanisms that allow yeast to grow under conditions of high concentrations of ammonium has become more and more important. RESULTS: To further understand the resistance mechanism of yeast to grow under high concentration of ammonium, we used NH4Cl to screen a yeast non-essential gene-deletion library. We identified 61 NH4Cl-sensitive deletion mutants from approximately 4200 mutants in the library, then 34 of them were confirmed by drop test analysis. Enrichment analysis of these 34 genes showed that biosynthesis metabolism, mitophagy, MAPK signaling, and other pathways may play important roles in NH4Cl resistance. Transcriptome analysis under NH4Cl stress revealed 451 significantly upregulated genes and 835 significantly downregulated genes. The genes are mainly enriched in: nitrogen compound metabolic process, cell wall, MAPK signaling pathway, mitophagy, and glycine, serine and threonine metabolism. CONCLUSIONS: Our results present a broad view of biological pathways involved in the response to NH4Cl stress, and thereby advance our understanding of the resistance genes and cellular transcriptional regulation under high concentration of ammonium.

Genome-Wide Identification of Cellular Pathways and Key Genes That Respond to Sodium Bicarbonate Stress in Saccharomyces cerevisiae.

Sodium bicarbonate (NaHCO3) is an important inorganic salt. It is not only widely used in industrial production and daily life, but is also the main stress in alkaline saline soil. NaHCO3 has a strong ability to inhibit the growth of fungi in both natural environment and daily application. However, the mechanism by which fungi respond to NaHCO3 stress is not fully understood. To further clarify the toxic mechanisms of NaHCO3 stress and identify the specific cellular genes and pathways involved in NaHCO3 resistance, we performed genome-wide screening with NaHCO3 using a Saccharomyces cerevisiae deletion mutant library. A total of 33 deletion mutants with NaHCO3 sensitivity were identified. Compared with wild-type strains, these mutants had significant growth defects in the medium containing NaHCO3. Bioinformatics analysis found that the corresponding genes of these mutants are mainly enriched in the cell cycle, mitophagy, cell wall integrity, and signaling pathways. Further study using transcriptomic analysis showed that 309 upregulated and 233 downregulated genes were only responded to NaHCO3 stress, when compared with yeast transcriptomic data under alkaline and saline stress. Upregulated genes were mainly concentrated in amino acid metabolism, steroid biosynthesis, and cell wall, while downregulated genes were enriched in various cellular metabolisms. In summary, we have identified the cellular pathways and key genes that respond to NaHCO3 stress in the whole genome, providing resource and direction for understanding NaHCO3 toxicity and cellular resistance mechanisms.

Multiparametric quantitative MRI for the evaluation of dysthyroid optic neuropathy.

OBJECTIVE: To evaluate the ability of quantitative MRI parameters for predicting dysthyroid optic neuropathy (DON). METHODS: We retrospectively collected and analyzed the clinical features and 3.0 T MRI data of 59 patients with Graves orbitopathy (GO), with (n = 26) and without DON (n = 33). We compared MRI quantitative parameters, including the modified muscle index (mMI), proptosis, volume of intra-orbital fat, mean apparent diffusion coefficient value, and T2 value of the optic nerve among patients with and without DON. A logistic regression analysis was performed to identify the risk factors associated with DON. Moreover, we performed a receiver operating characteristic curve analysis and decision curve analysis to evaluate the diagnostic performance of the identified parameters for DON. RESULTS: We studied 118 orbits (43 and 75 with and without DON, respectively). The mMI and mean T2 value of the optic nerve were significantly greater in orbits with DON (p < 0.001). A greater mMI at 21 mm (odds ratio (OR), 1.039; 95% confidence interval (CI): 1.019, 1.058) and higher mean T2 value of the optic nerve (OR, 1.035; 95% CI: 1.017, 1.054) were associated with a higher risk of DON. A model combining the mMI at 21 mm and mean T2 values for the optic nerve effectively predicted DON in patients with GO, with a sensitivity and specificity of 95.3% and 76%, respectively. CONCLUSION: A quantitative MRI parameter combining the mMI at 21 mm and mean T2 value of the optic nerve can be an effective imaging marker for identifying DON. KEY POINTS: • Patients with GO and DON had greater mMI than those without DON. • Optic nerves in patients with DON demonstrated an increased T2 value. • The quantitative MRI parameter combining the mMI at 21 mm and mean T2 value of the optic nerve is the most effective method for diagnosing DON.

Adrenal pheochromocytoma: is it all or the tip of the iceberg?

Adrenal pheochromocytoma is not always a simple retroperitoneal tumor but may be part of a more complicated condition. It often has a spectrum of complex and variable imaging features, may present as a collision tumor and composite tumor, and is associated with a variety of clinical syndromes. A comprehensive understanding of the clinical, pathological, and variable imaging manifestations of pheochromocytoma can help radiologists make an accurate diagnosis. This article reviews various special imaging features of pheochromocytoma and pheochromocytoma-related diseases.

Anti-inflammatory sesquiterpenoids from the heartwood of Juniperus formosana Hayata.

Juniperus formosana Hayata (J. formosana) is a commom needlebush cultivar growing in China. Six new compounds (1-6), including four cadinene sesquiterpenoids (1-4), one abietane diterpenoid (5), and one ß-naphthol derivative (6), along with 18 known compounds (7-24) were isolated and identified through phytochemical investigation on the heartwood of J. formosana. The structures of these compounds were fully elucidated by their 1D and 2D NMR, HR-ESI-MS, UV, and IR spectral data analyses. The absolute configurations of compounds 1, 3, and 5 were confirmed by experimental and calculated electronic circular dichroism (ECD) data. Moreover, X-ray crystallographic analysis was carried out to characterize the structure of compound 4. The inhibitory effects on the nitric oxide (NO) production of all the isolated compounds were initially examined in RAW264.7 macrophages induced by lipopolysaccharide (LPS). The results showed that compounds 3 and 12 possessed significant inhibitory potency on NO generation with IC50 values of 3.41 µM and 6.15 µM among the new and known compounds, respectively. The expressions of IL-1ß, IL-6, and TNF-α were measured in LPS-stimulated RAW264.7 cells to evaluate the anti-inflammatory effects of compounds 1-24. Compounds 1-6 and 9-12 exhibited potent anti-inflammatory effects. Additionally, the expressions of p38, Erk, and IκBα proteins were further determined to explore the anti-inflammatory mechanism of the most potent compounds 3 and 12. Overall, our findings indicate the potential of J. formosana for developing medicine candidates as the treatments of inflammation.

Retromer Complex and PI3K Complex II-Related Genes Mediate the Yeast (Saccharomyces cerevisiae) Sodium Metabisulfite Resistance Response.

Sodium metabisulfite (Na2S2O5) is widely used as a preservative in the food and wine industry. However, it causes varying degrees of cellular damage to organisms. In order to improve our knowledge regarding its cyto-toxicity, a genome-wide screen using the yeast single deletion collection was performed. Additionally, a total of 162 Na2S2O5-sensitive strains and 16 Na2S2O5-tolerant strains were identified. Among the 162 Na2S2O5 tolerance-related genes, the retromer complex was the top enriched cellular component. Further analysis demonstrated that retromer complex deletion leads to increased sensitivity to Na2S2O5, and that Na2S2O5 can induce mislocalization of retromer complex proteins. Notably, phosphatidylinositol 3-monophosphate kinase (PI3K) complex II, which is important for retromer recruitment to the endosome, might be a potential regulator mediating retromer localization and the yeast Na2S2O5 tolerance response. Na2S2O5 can decrease the protein expressions of Vps34, which is the component of PI3K complex. Therefore, Na2S2O5-mediated retromer redistribution might be caused by the effects of decreased Vps34 expression levels. Moreover, both pharmaceutical inhibition of Vps34 functions and deletions of PI3K complex II-related genes affect cell tolerance to Na2S2O5. The results of our study provide a global picture of cellular components required for Na2S2O5 tolerance and advance our understanding concerning Na2S2O5-induced cytotoxicity effects.

Subjective burdens among informal caregivers of critically ill patients: a cross-sectional study in rural Shandong, China.

BACKGROUND: Informal caregivers are the main source of care for the critically ill, especially after discharge or during the terminal stages at home. However, the concern for informal caregivers is often overshadowed by critically ill patients. The purpose of this study is to determine the influencing factors of the subjective burden of informal caregivers and to seek solutions accordingly. METHODS: Between July and August 2019, a cross-sectional study was conducted in Shandong, China, focusing on family caregivers and critically ill patients. Subjective caregiver burden was measured by the Chinese version of Zarit Burden Interview (ZBI). The stress process model was used to identify conditions relevant to the caregiving burden and to assess their impact on family caregivers. RESULTS: 554 samples were selected for analysis. The average scores of Zarit Caregiver Burden Interview (ZBI) scores in this study was 30.37±19.04 (n=554). ZBI scores of older, less educated, and spouse caregivers were significantly lower (4.12; 95%CI, 0.42 to 7.81; P =0.029). Objective and subjective burdens increased proportionally. Secondary role stress factors included the higher out-of-pocket (OOP) costs of critical diseases and lower household income, both of which increased caregivers' subjective burdens (1.28; 95%CI, -0.06 to 2.63; p=0.062). Formal medical aid systems played a positive role in reducing subjective caregiving burdens (-7.31; 95%CI, -13.23 to -1.40; p=0.016). CONCLUSIONS: Health policies should address both the direct medical burdens and the intangible psychological burdens of critical diseases.

Association between livelihood capital and catastrophic health expenditure among patients with critical illness: a cross-sectional study in rural Shandong, China.

OBJECTIVE: The objective of this study is to examine the association between livelihood capital and catastrophic health expenditure (CHE). DESIGN: Between July and August 2019, a cross-sectional study was conducted in critically ill patients. SETTING: Shandong, China. PARTICIPANTS: 1041 households with critically ill patients from 77 villages. PRIMARY AND SECONDARY OUTCOME MEASURES: We defined expenditure as being catastrophic if a household's out-of-pocket payments were greater than or equal to 40% of their capacity to pay. Using the sustainable livelihoods framework, this study explored the associations between CHE and the various forms of livelihood capital-inclusive of human capital, natural capital, physical capital, financial capital and social capital. χ2 tests, t-tests, Wilcoxon tests and binary logistic regression analysis were performed to examine these associations. RESULTS: The incidence of CHE among households with critically ill patients was 76.37% in this study. Better livelihood capital was significantly associated with lower incidence of CHE. After controlling for confounding factors, households with healthier patients (OR 0.47, 95% CI 0.23 to 0.96), more real estate ownership (OR 0.35, 95% CI 0.19 to 0.67) and better economic status (OR 0.33, 95% CI 0.18 to 0.62) were associated with a reduction in the occurrence of CHE. CONCLUSIONS: Livelihood capital was significantly associated with CHE in rural families with critically ill patients. This association suggests that, in addition to providing health insurance to the critically ill, more attention should be paid to their ability to create and preserve livelihood capital.

Association between social capital and depression among critically ill patients: evidence from a cross-sectional study in rural Shandong, China.

BACKGROUND: With an increasing number of critically ill patients, attention should be paid to both their physical health and mental health. The objective of this study is to examine the links between depression and social capital among critically ill patients. METHODS: Data for 1043 patients with critical illnesses was collected with a stratified cluster random sampling method in rural Shandong, China. Depression symptoms were measured using a short form version of the Center for Epidemiologic Studies Depression Scale (CESD-10) and the total scores of them were dichotomized. We associated structural social capital with social networks, social participation, and social support. Cognitive social capital includes the degree of availability of social trust and reciprocity. Binary logistic regression was used to explore whether social capital was significantly associated with depression among patients with critical illnesses. RESULTS: We found that 68.5% of the critically ill patients in our sample population had depression. CESD-10 scores were negatively correlated with social capital, including occupations of their frequent contacts, social trust in relatives and friends, distance to the nearest medical institution and medical assistance convenience from non-spouse. In addition, low economic status, and low self-rated health were more significantly correlated with depression in critically ill patients. CONCLUSIONS: Our findings suggest that more attention should be paid to the mental health of critically ill patients and more formal society, community and government support form given, particularly in rural China.

Appraisal of China's Response to the Outbreak of COVID-19 in Comparison With SARS.

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2, was first reported in Wuhan, China, in December 2019 and has since become a pandemic. The COVID-19 containment measures were comparable to those used with severe acute respiratory syndrome (SARS), although these were stricter and more organized, and were initiated earlier and on a larger scale. Based on the lessons learned from SARS, the Chinese government acted aggressively in response to COVID-19, through a unified and effective commanding system, using law-based and science-driven strategies, and coordinated deployment of medical resources. Additionally, the application of high-tech measures, traditional Chinese medicine, and hierarchical medical systems also played an important role in control measures. Despite the remarkable performance, the initial delay in response suggests that the coordination between public health and medical services, reserve and coordination of emergency materials, and capacity for disease control and prevention need to be strengthened.

A Genome-Wide Screen in Saccharomyces cerevisiae Reveals a Critical Role for Oxidative Phosphorylation in Cellular Tolerance to Lithium Hexafluorophosphate.

Lithium hexafluorophosphate (LiPF6) is one of the leading electrolytes in lithium-ion batteries, and its usage has increased tremendously in the past few years. Little is known, however, about its potential environmental and biological impacts. In order to improve our understanding of the cytotoxicity of LiPF6 and the specific cellular response mechanisms to it, we performed a genome-wide screen using a yeast (Saccharomyces cerevisiae) deletion mutant collection and identified 75 gene deletion mutants that showed LiPF6 sensitivity. Among these, genes associated with mitochondria showed the most enrichment. We also found that LiPF6 is more toxic to yeast than lithium chloride (LiCl) or sodium hexafluorophosphate (NaPF6). Physiological analysis showed that a high concentration of LiPF6 caused mitochondrial damage, reactive oxygen species (ROS) accumulation, and ATP content changes. Compared with the results of previous genome-wide screening for LiCl-sensitive mutants, we found that oxidative phosphorylation-related mutants were specifically hypersensitive to LiPF6. In these deletion mutants, LiPF6 treatment resulted in higher ROS production and reduced ATP levels, suggesting that oxidative phosphorylation-related genes were important for counteracting LiPF6-induced toxicity. Taken together, our results identified genes specifically involved in LiPF6-modulated toxicity, and demonstrated that oxidative stress and ATP imbalance maybe the driving factors in governing LiPF6-induced toxicity.

A CT-based nomogram for predicting the malignant potential of primary gastric gastrointestinal stromal tumors preoperatively.

PURPOSE: To develop and validate a computerized tomography (CT)-based nomogram for predicting the malignant potential of primary gastric gastrointestinal stromal tumors (GISTs). METHODS: The primary and validation cohorts consisted of 167 and 39 patients (single center, different time periods) with histologically confirmed primary gastric GISTs. Clinical data and preoperative CT images were reviewed. The association of CT characteristics with malignant potential was analyzed using univariate and stepwise logistic regression analyses. A nomogram based on significant CT findings was developed for predicting malignant potential. The predictive accuracy of the nomogram was determined by the concordance index (C-index) and calibration curves. External validation was performed with the validation cohort. RESULTS: CT imaging features including tumor size, tumor location, tumor necrosis, growth pattern, ulceration, enlarged vessels feeding or draining the mass (EVFDM), tumor contour, mesenteric fat infiltration, and direct organ invasion showed significant differences between the low- and high-grade malignant potential groups in univariate analysis (P < 0.05). Only tumor size (> 5 cm vs ≤ 5 cm), location (cardiac/pericardial region vs other), EVFDM, and mesenteric fat infiltration (present vs absent) were significantly associated with high malignant potential in multivariate logistic regression analysis. Incorporating these four independent factors into the nomogram model achieved good C-indexes of 0.946 (95% confidence interval [CI] 0.899-0.975) and 0.952 (95% CI 0.913-0.977) in the primary and validation cohorts, respectively. The cutoff point was 0.33, with sensitivity, specificity, and diagnostic accuracy of 0.865, 0.915, and 0.780, respectively. DISCUSSION: Primary gastric GISTs originating in the cardiac/pericardial region appear to be associated with higher malignant potential. The nomogram consisting of CT features, including size, location, EVFDM, and mesenteric fat infiltration, could be used to accurately predict the high malignant potential of primary gastric GISTs.

Optical tweezers-controlled hotspot for sensitive and reproducible surface-enhanced Raman spectroscopy characterization of native protein structures.

Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful tool to detect biomolecules in aqueous environments. However, it is challenging to identify protein structures at low concentrations, especially for the proteins existing in an equilibrium mixture of various conformations. Here, we develop an in situ optical tweezers-coupled Raman spectroscopy to visualize and control the hotspot between two Ag nanoparticle-coated silica beads, generating tunable and reproducible SERS enhancements with single-molecule level sensitivity. This dynamic SERS detection window is placed in a microfluidic flow chamber to detect the passing-by proteins, which precisely characterizes the structures of three globular proteins without perturbation to their native states. Moreover, it directly identifies the structural features of the transient species of alpha-synuclein among its predominant monomers at physiological concentration of 1 µM by reducing the ensemble averaging. Hence, this SERS platform holds the promise to resolve the structural details of dynamic, heterogeneous, and complex biological systems.