A capillary electrophoresis strategy to sensitively detect dynamic properties of coiled coil polypeptides.

The self-assembly behavior of polypeptides plays an essential role to form biological and functional macromolecules, which have attracted a lot of attention due to their excellent characters. Understanding the polypeptide self-assembly systems and dynamic behaviors is fundamental to improve the potential of biomedical applications. In this work, coiled coil polypeptides PC10 and PC10 P were designed and biosynthesized. PC10 and PC10 P could form nanogels when the concentration of polypeptides was less than 2% (m/v). The dynamic behaviors of PC10 and PC10 P were measured by Förster resonance energy transfer method based on a capillary electrophoresis system. The Förster resonance energy transfer efficiency of this system was 60.4%, and the distance of self-assembled domains in the polypeptides was calculated as 6.14 nm, demonstrating that the exchange behavior occurred between two different polypeptides containing the same coiled coil region.

Thermodynamics of NaHCO3 decomposition during Na2CO3-based CO2 capture.

Amine-basedcarbon-capture technologies have been shown to be energetically expensive and to cause significant environmental and epidemiological impacts due to their volatility. Bicarbonate formation from carbon dioxide's reaction with water has been suggested as an effective alternative for capturing CO2; however, the thermodynamics of this reaction are not well understood. This study experimentally determined the equilibrium constant of sodium bicarbonate (NaHCO3) decomposition to sodium, water, and carbon dioxide; the study also compared the equilibrium constant to theoretical calculations. Using a combination of experimentation and thermodynamic relationships, the unitless equilibrium constants of the forward and reverse reactions were calculated accurately (error <±9% and <±4%, respectively). Equilibrium data were calculated using enthalpy and entropy values of each component of NaHCO3 decomposition at temperatures ranging from 25 to 155°C respectively. These results offer more data essential to optimizing NaHCO3 use in environmentally friendly next-generation CO2-capture technologies.

Diagnostic Performance of PET/CT Using 18F-FACBC in Prostate Cancer: A Meta-Analysis.

Background: Diagnostic performance of PET/CT using 18F-fluciclovine (18F-FACBC) in patients with prostate cancer (PCa) has been evaluated in only a few studies. There is no consensus on the diagnostic value of 18F-FACBC PET/CT in PCa recurrence or metastasis (except for bone metastasis), the primary diagnosis of the lesion. Hence, a meta-analysis was conducted to evaluate the performance of 18F-FACBC PET/CT. Methods: The literature published from June 2015 to June 2019 on using 18F-FACBC PET/CT for the diagnosis of PCa was retrieved from PubMed and EMBASE. Pooled sensitivity (Sen), specificity (Spe), positive and negative likelihood ratios (LR+ and LR-), area under the curve (AUC), and diagnostic odds ratio (DOR) of 18F-FACBC PET/CT in patients with PCa were calculated. An SROC map was made, and a meta-regression analysis was carried out. A Fagan plot and likelihood ratio dot plot were drawn. Sensitivity and funnel plot analysis were made. Meta-disc, Review Manager 5.3, and STATA 13 were used for the meta-analysis. Results: A total of nine articles met the strict criteria for diagnostic meta-analysis, which included 363 patients and 345 lesions. Pooled Sen, Spe, LR+, LR-, DOR were 0.88, 0.73, 3.3, 0.17, and 20, respectively. Lesions detected on the PET/CT image included primary lesions and metastases. For the lesion, the doctors considered the abnormal part as a lesion on the PET/CT image by their own experience and expertise, including primary lesions and metastases. For the patient, patients who participated in the trial can be diagnosed as PCa through 18F-FACBC. Conclusion: This study comprehensively evaluated the diagnostic value of 18F-FACBC PET/CT on PCa. Our analysis suggests that 18F-FACBC PET/CT is a valuable agent in diagnosing PCa. More studies are needed for further validation.

Clinicopathological features and treatment outcomes of metastatic or locally unresectable small bowel adenocarcinoma.

PURPOSE: Small bowel adenocarcinoma (SBA) is an uncommon malignancy with poor prognosis and therefore difficult to study. The purpose of this study was to evaluate the characteristics, treatments and prognostic factors in patients with metastatic or locally unresectable SBA. METHODS: Epidemiological and treatment data from metastatic or locally unresectable SBA patients who were admitted to Peking Union Medical College Hospital for first-line chemotherapy between December 2003 and November 2016 were retrospectively analyzed. RESULTS: Of the 34 enrolled patients, 22 (64.7%) were male and 12 (35.3%) female, with a median age of 52 years. Tumors originated in the duodenum in 24 (70.6%) patients. All patients received one of the following regimens as first-line therapy: FOLFOX or XELOX (n = 27), FOLFIRI or CAPIRI (n = 5), GEMOX (n = 1), and TP (n = 1). The response rate and disease control rate were 11.8 and 61.8%, respectively. The median progression-free survival (PFS) and overall survival (OS) were 4.5 and 13.8 months, respectively. Multivariate analysis revealed that liver metastasis was independently associated with poor PFS, and both unresected primary tumor and males were significantly associated with poor OS. The survival of three metastatic patients was 52-96 months after combination treatment of chemotherapy, resection of primary tumor and metastasis. CONCLUSIONS: The prognosis of metastatic or locally unresectable SBA was poor, and unresected primary tumor and males were significantly associated with poor OS. Combined modality therapy of systemic chemotherapy combined with local treatment of the primary tumor and oligometastasis might improve prognosis in selected patients.

HIV-related DNA detection through switching on hybridized quenched fluorescent DNA-Ag nanoclusters.

In this paper, DNA containing six cytosines as the formation site for silver nanoclusters (Ag NCs) was adopted as a template for preparing fluorescent DNA-Ag NCs. For the first time, it was found that the fluorescence of DNA-Ag NCs could be quenched after hybridization with their complementary sequence. On the basis of this new phenomenon, we designed a sequence C1 that was completely complementary to human immunodeficiency virus (HIV) DNA, and probe DNA which was partially complementary to C1 for the synthesis of DNA-Ag NCs. The fluorescence of DNA-Ag NCs was quenched after hybridization with C1 and the DNA-Ag NCs/C1 composite was formed, while C1 could be dissociated away from the DNA-Ag NCs by HIV DNA through a strand exchange reaction due to the stronger affinity between HIV DNA and C1, which could switch on the quenched Ag NCs, thus a new "off-on" fluorescence method for HIV DNA detection was developed. In the experiment, the Ag NCs formation site of DNA, the number of base pairs, and the pH and salt concentration of binding buffer were optimized. Under the optimum conditions, the limit of detection for HIV DNA was obtained to be 3.18 nM (3σ/N, n = 7) with the linear range of 15-150 nM for the 150 nM DNA-Ag NCs/C1 probe. Besides, the probe showed excellent specificity to HIV DNA, and even distinguished one nucleotide mismatched HIV DNA.

Exosomes Derived from Hypoxia-Treated Human Adipose Mesenchymal Stem Cells Enhance Angiogenesis Through the PKA Signaling Pathway.

Angiogenesis is a complicated and sequential process that plays an important role in different physiological processes. Mesenchymal stem cells (MSCs), which are pluripotent stem cells, are widely used for the treatment of ischemic and traumatic diseases, and exosomes derived from these cells can also promote angiogenesis. Therefore, we aimed to uncover mechanisms to improve MSC exosome-mediated angiogenesis. For this study, we isolated human adipose-derived MSCs (hAD-MSCs) and assessed differentiation ability and markers. Cells were divided into hypoxia-treated MSCs (H-MSCs) and normoxia-treated MSCs (N-MSC), and exosomes were extracted by ultrafiltration. Exosomes (100 µg/mL) from H-MSCs and N-MSCs were added to human umbilical vein endothelial cells (HUVECs). Exosome uptake and the ability of endothelial cells to form tubes were detected in real time. Protein samples were collected at different time points to detect the expression of inhibitors (Vash1) and enhancers (Angpt1 and Flk1) of angiogenesis; we also assessed their related signaling pathways. We found that exosomes from the hypoxia group were more easily taken up by HUVECs; furthermore, their angiogenesis stimulatory activity was also significantly enhanced compared to that with exosomes from the normoxia group. HUVECs exposed to exosomes from H-MSCs significantly upregulated angiogenesis-stimulating genes and deregulated angiogenesis-inhibitory genes. The expression of vascular endothelial growth factor (VEGF) and activation of the protein kinase A (PKA) signaling pathway in HUVECs were significantly increased by hypoxia-exposed exosomes. Moreover, a PKA inhibitor was shown to significantly suppress angiogenesis. Finally, we concluded that hypoxia-exposed exosomes derived from hAD-MSCs can improve angiogenesis by activating the PKA signaling pathway and promoting the expression of VEGF. These results could be used to uncover safe and effective treatments for traumatic diseases.

In vivo tumor active cancer targeting and CT-fluorescence dual-modal imaging with nanoprobe based on gold nanorods and InP/ZnS quantum dots.

In this paper, gold nanorods and InP/ZnS quantum dots were encapsulated together in a silica medium, and the targeting molecular peptide c(RGDfC) was further connected after surface modification with PEG and PEG derivatives to prepare a multifunctional Au@QD@SiO2/PEG-c(RGDfC) probe. Dynamic Light Scattering showed that the probe size was about 215.01 ± 2.72 nm, and its dispersibility was good. In in vitro experiments when the concentration was as high as 200 µg mL-1, the activity of the cells was still 85% due to low toxicity. In vivo experiments showed that the probe had excellent tumor targeting, X-ray computed tomography (CT) imaging and fluorescence imaging capabilities. The experiments revealed that the probe had a long blood circulation time (T1/2 = 7.78 h) in mice. Biochemical analysis, liver enzyme analysis and histomorphological analysis after probe injection showed that the probe had no obvious side effects on the normal functions of the main organs, indicating good biosafety. In vivo imaging experiments showed that 6 d after intravenous injection, the tumor sites of a HeLa tumor-bearing nude mice positive group presented obvious fluorescence and CT signals, indicating that the prepared nanoprobe had good tumor targeting dual-mode imaging capabilities and therefore showed great potential in biomedical imaging applications, especially the diagnosis of cancer.