[Variations of glucose content in Massa Medicata Fermentata during processing based on quantitative proton nuclear magnetic resonance].

A quantitative proton nuclear magnetic resonance(qHNMR) method was established to determine the glucose content in commercially available Massa Medicata Fermentata(MMF) products and explore the variations of glucose content in MMF products during processing. The qHNMR spectrum of MMF in deuterium oxide was obtained with 2,2,3,3-d_4-3-(trimethylsilyl) propionate sodium salt as the internal standard substance. With the doublet peaks of terminal hydrogen of glucose with chemical shift at δ 4.65 and δ 5.24 as quantitative peaks, the content of glucose in MMF samples was determined. The glucose content showed a good linear relationship within the range of 0.10-6.44 mg·mL~(-1). The relative standard deviations(RSDs) of precision, stability, repeatability, and recovery for determination were all less than 2.3%. The glucose content varied in different commercially available MMF samples, which were associated with the different fermentation days, wheat bran-to-flour ratios, and processing methods. The glucose content in MMF first increased and then decreased over the fermentation time. Compared with the MMF products fermented with wheat bran or flour alone, the products fermented with both wheat bran and flour had increased glucose. The glucose content of bran-fried MMF was slightly lower than that of raw MMF, while the glucose content in charred MMF was extremely low. In conclusion, the qHNMR method established in this study is simple, fast, and accurate, serving as a new method for determining the glucose content in MMF. Furthermore, this study clarifies the variations of glucose content in MMF during processing, which can not only indicate the processing degree but also provide a scientific basis for revealing the fermentation mechanism and improving the quality control of MMF.

Relationship between serum alkaline phosphatase and poor 3-month prognosis in acute ischemic stroke patients with preserved renal function: results from Xi'an Stroke Registry Study of China.

BACKGROUND: In recent years, alkaline phosphatase (ALP) has been considered as one of the independent risk factors of acute ischemic stroke (AIS) and leads to worse clinical outcomes in patients with renal failure. In this study, we aim to investigate whether serum ALP level is associated with poor early-term prognosis in relationship of AIS patients with preserved renal function. METHODS: A prospectively collected database of AIS patients hospitalized in the Xi'an district of China from January to December, 2015 was analyzed. The demographics, serum ALP levels and stroke outcomes of all patients at 3 months were reviewed. Patients were routinely followed-up for 3 months. Serum ALP level was analyzed as a continuous variable and quintiles (Q1-Q5). Multivariate logistic regression model and a two-piecewise linear regression model were used to investigate the relationship and to determine the threshold effect regarding serum ALP levels and poor 3-month prognosis of AIS patients with preserved renal function. RESULTS: Overall, 1922 AIS patients were enrolled with 62.3% of them being men. The risk of having a poor 3-month prognosis was significantly increased in Q1, Q2, Q3 and Q5, when compared to that in Q4 being as the reference. The highest risk was noted in Q5 (odds ratio 2.21, 95% confidence interval: 1.32-3.73, P = 0.003) after being adjusted for confounders. Further analysis revealed a J-shaped curvilinear relationship between ALP levels and a poor 3-month prognosis of strokes (optimal threshold ALP level = 90 U/L). The relationship between both parameters was not significantly affected by age, sex, drinking, hypertension and leukocyte count (stratified by 10 × 109/L) (P for interaction > 0.05). CONCLUSIONS: Serum ALP was noted as an independent risk factor for a poor 3-month prognosis of AIS patients with preserved renal function. ALP levels higher than 90 U/L could cause an increased risk of a poor 3-month prognosis.

Longitudinal clinical and radiographic evaluation reveals interleukin-6 as an indicator of persistent pulmonary injury in COVID-19.

Rationale: Previous studies of coronavirus disease 2019 (COVID-19) were mainly focused on cross-sectional analysis. In this study, we sought to evaluate the dynamic changes of immunological and radiographic features, and the association with the outcome of pulmonary lesions in COVID-19 patients. Methods: Peripheral blood samples and radiographic data were collected longitudinally for up to 8 weeks from 158 laboratory-confirmed COVID-19 patients. The chest computed tomography (CT) scans were scored based on a semi-quantification assessment according to the extent of pulmonary abnormalities; the temporal change of the immunological and radiographic features was analyzed. Results: Compared with mild and moderate patients, severe patients had significantly decreased counts of lymphocytes, CD4+ T cells, CD8+ T cells, and CD19+ B cells but dramatically elevated counts of neutrophils and levels of interleukin (IL)-6. Sequential monitoring showed a sustained increase in lymphocytes counts and significantly decreased levels of IL-6 in severe patients during the disease course. Notably, patients with persistent pulmonary lesions (CT score ≥ 5 in week 8) showed high levels of IL-6 during the follow-up period, compared with those with recovery lesions (CT score < 5 in week 8). More importantly, the peak expression of IL-6 prior to the aggravated lung injury was mainly found in patients with persistent lesions, and multivariate analysis showed that IL-6 level upon admission was an independent factor associated with the persistent pulmonary injury. Conclusion: Prolonged elevation of IL-6 is associated with persistent pulmonary lesions in COVID-19 patients. Sequential monitoring and timely intervention of IL-6 may favor the clinical management of COVID-19.

A Tool for Early Prediction of Severe Coronavirus Disease 2019 (COVID-19): A Multicenter Study Using the Risk Nomogram in Wuhan and Guangdong, China.

BACKGROUND: Because there is no reliable risk stratification tool for severe coronavirus disease 2019 (COVID-19) patients at admission, we aimed to construct an effective model for early identification of cases at high risk of progression to severe COVID-19. METHODS: In this retrospective multicenter study, 372 hospitalized patients with nonsevere COVID-19 were followed for > 15 days after admission. Patients who deteriorated to severe or critical COVID-19 and those who maintained a nonsevere state were assigned to the severe and nonsevere groups, respectively. Based on baseline data of the 2 groups, we constructed a risk prediction nomogram for severe COVID-19 and evaluated its performance. RESULTS: The training cohort consisted of 189 patients, and the 2 independent validation cohorts consisted of 165 and 18 patients. Among all cases, 72 (19.4%) patients developed severe COVID-19. Older age; higher serum lactate dehydrogenase, C-reactive protein, coefficient of variation of red blood cell distribution width, blood urea nitrogen, and direct bilirubin; and lower albumin were associated with severe COVID-19. We generated the nomogram for early identifying severe COVID-19 in the training cohort (area under the curve [AUC], 0.912 [95% confidence interval {CI}, .846-.978]; sensitivity 85.7%, specificity 87.6%) and the validation cohort (AUC, 0.853 [95% CI, .790-.916]; sensitivity 77.5%, specificity 78.4%). The calibration curve for probability of severe COVID-19 showed optimal agreement between prediction by nomogram and actual observation. Decision curve and clinical impact curve analyses indicated that nomogram conferred high clinical net benefit. CONCLUSIONS: Our nomogram could help clinicians with early identification of patients who will progress to severe COVID-19, which will enable better centralized management and early treatment of severe disease.

Immunopathological characteristics of coronavirus disease 2019 cases in Guangzhou, China.

Coronavirus disease 2019 (COVID-19) is a respiratory disorder caused by the highly contagious severe acute respiratory syndrome coronavirus 2. The immunopathological characteristics of patients with COVID-19, either systemic or local, have not been thoroughly studied. In the present study, we analysed both the changes in the number of various immune cell types as well as cytokines important for immune reactions and inflammation. Our data indicate that patients with severe COVID-19 exhibited an overall decline of lymphocytes including CD4+ and CD8+ T cells, B cells and natural killer cells. The number of immunosuppressive regulatory T cells was moderately increased in patients with mild COVID-19. Interleukin-6 (IL-6), IL-10 and C-reactive protein were remarkably up-regulated in patients with severe COVID-19. In conclusion, our study shows that the comprehensive decrease of lymphocytes, and the elevation of IL-6, IL-10 and C-reactive protein are reliable indicators of severe COVID-19.

Risk factors affecting the 1-year outcomes of minor ischemic stroke: results from Xi'an stroke registry study of China.

BACKGROUND: The prevalence of stroke recurrence, disability, and all-cause mortality of patients with minor ischemic stroke (MIS) remains problematic. The aim of the present study was to identify risk factors associated with adverse outcomes at 1 year after MIS in the Xi'an region of China. METHODS: This prospective cohort study included MIS patients above 18 years old with National Institutes of Health Stroke Scale (NIHSS) score ≤ 3 who were treated in any of four hospitals in Xi'an region of China between January and December 2015. The 1-year prevalence of stroke recurrence, disability, and all-cause mortality were evaluated, respectively. Multivariate logistic regression analysis was performed to assess the association between the identified risk factors and clinical outcomes. RESULTS: In this study, 131(10.5%, 131/1252) patients were lost to follow-up at 1 year. A total of 1121 patients were included for analysis, the prevalence of stroke recurrence, disability, and all-cause mortality at 1 year after MIS were 3.4% (38/1121), 9.3% (104/1121), and 3.3% (37/1121), respectively. Multivariate logistic regression analysis identified age, current smoking, and pneumonia as independent risk factors for stroke recurrence. Age, pneumonia, and alkaline phosphatase were independent risk factors for all-cause mortality. Independent risk factors for disability were age, pneumonia, NIHSS score on admission, and leukocyte count. CONCLUSIONS: The 1-year outcomes of MIS in Xi'an region of China were not optimistic, especially with a high prevalence of disability. The present study indicated that age and pneumonia were the common independent risk factors affecting the 1-year outcomes of MIS in Xi'an region of China.

Platelet microvesicles promote the recovery of neurological function in mouse model of cerebral infarction by inducing angiogenesis.

The aim of this study is to investigate the effect of PMVs on mice with ischemic cerebral infarction and its mechanism. Male C57BL/6 mice were selected, and the right focal cortical infarction model was established via cauterization under a microscope and randomly divided into sham operation (Sham) group, normal saline control (Saline) group and platelet microvesicles intervention (PMVs) group. At 1 h after modeling, 5 µL of PMVs (50 µg/mL) or normal saline was injected into the lateral ventricle. The neurological function of mice in each group was evaluated at 1, 3, 7, 14 and 28 d after modeling. After 28 d, the cerebral infarction area was detected via 2,3,5-triphenyltetrazolium chloride (TTC) staining. At 7 and 28 d after modeling, the blood vessel density, proliferation rate of new vessels and encapsulation rate of pericytes were detected via immunofluorescence staining. Moreover, the changes in cerebral cortical blood flow at the infarction side were detected before modeling and at 7 and 28 d after modeling, respectively. Finally, the expressions of proangiogenic factors vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1) and N-Cadherin were detected via Western blotting at 3, 7 and 28 d after modeling. PMVs could promote the improvement of neurological function and significantly reduce the cerebral infarction volume in mice with cerebral infarction. PMVs promoted proliferation of new vessels and increased blood vessel density at the infarction edge in mice with cerebral infarction. PMVs could increase the encapsulation rate of pericytes at the infarction edge and improve the permeability of blood-brain barrier in mice with cerebral infarction. PMVs could increase the cerebral cortical blood flow perfusion in mice with cerebral infarction. PMVs could increase proangiogenic factors in brain tissues in mice with cerebral infarction. PMVs could significantly improve the recovery of neurological function in mice with cerebral infarction, which is closely related to the ability of PMVs to promote angiogenesis at the infarction edge. The possible mechanism is that PMVs facilitate angiogenesis after cerebral infarction through promoting the expressions of VEGF, Ang-1 and N-Cadherin. More importantly, the new vessels promoted by PMVs have complete structure and perfect function, and can improve the cerebral blood flow perfusion at the infarction side.

Saikosaponin-D Reduces H2O2-Induced PC12 Cell Apoptosis by Removing ROS and Blocking MAPK-Dependent Oxidative Damage.

Neuronal oxidative stress (OS) injury has been proven to be associated with many neurodegenerative diseases, and thus, antioxidation treatment is an effective method for treating these diseases. Saikosaponin-D (SSD) is a sapogenin extracted from Bupleurum falcatum and has been shown to have many pharmacological activities. The main purpose of this study was to investigate whether and how SSD protects PC12 cells from H2O2-induced apoptosis. The non-toxic level of SSD significantly mitigated the H2O2-induced decrease in cell viability, reduced the apoptosis rate, improved the nuclear morphology, and reduced caspase-3 activation and poly ADP-ribose polymerase (PARP) cleavage. Additionally, exogenous H2O2-induced apoptosis by damaging the intracellular antioxidation system. SSD significantly slowed the H2O2-induced release of malonic dialdehyde (MDA) and lactate dehydrogenase and increased the activity of superoxide dismutase (SOD) and the total antioxidant capacity, thereby reducing apoptosis. More importantly, SSD effectively blocked H2O2-induced phosphorylation of extracellular-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (p38MAPK), and specific inhibitors of ERK, JNK, and p38-reduced OS injury and apoptosis, suggesting that SSD reduces OS injury and apoptosis via MAPK signalling pathways. Finally, we confirmed that SSD significantly reduced H2O2-induced reactive oxygen species (ROS) accumulation, and the ROS inhibitor blocked the apoptosis caused by MAPK activation and cellular oxidative damage. In short, our study confirmed that SSD reduces H2O2-induced PC12 cell apoptosis by removing ROS and blocking MAPK-dependent oxidative damage.

Expanding the structural diversity of Bcr-Abl inhibitors: Hybrid molecules based on GNF-2 and Imatinib.

In order to expand the structural diversity of Bcr-Abl inhibitors, twenty hybrids (series E and P) have been synthesized and characterized based on Imatinib and GNF-2. Their biological activities were evaluated in vitro against human leukemia cells. Most compounds exhibited potent antiproliferative activity against K562 cells, especially for compounds E4, E5 and E7. Furthermore, these new hybrids were also screened for Abl kinase inhibitory activity, and some of them inhibited Abl kinase with low micromolar IC50 values. In particular, compound P3 displayed the most potent activity with IC50 value of 0.017 µM comparable with that of Imatinib. Molecular docking studies indicated that these novel hybrids fitted well with the active site of Bcr-Abl. These results suggested the great potential of these compounds as novel Bcr-Abl inhibitors.

Discovery of novel Bcr-Abl inhibitors with diacylated piperazine as the flexible linker.

Forty-two compounds (series 8, 9 and 10) incorporated with diacylated piperazine have been synthesized and evaluated as novel Bcr-Abl inhibitors based on 'six-atom linker'. Five of them, 8d, 8h, 8l, 10m and 10p, displayed potent Bcr-Abl inhibitory activity comparable with Imatinib. Moreover, compounds 8e, 10q, 10s, and 10u were potent Bcr-Abl inhibitors with IC50 values at the sub-micromolecular level. Most compounds exhibited moderate to high antiproliferative activity against K562 cells. In particular, compound 9e was the most promising Bcr-Abl inhibitor. Docking studies revealed that the binding modes of these compounds were similar with Imatinib. These compounds could be considered as promising lead compounds for further optimization.

Discovery of biphenyl-aryl ureas as novel VEGFR-2 inhibitors. Part 4: exploration of diverse hinge-binding fragments.

VEGFR-2 plays an essential role in angiogenesis and is an important target for cancer therapy. A series of biphenyl-aryl ureas were synthesized and evaluated as novel VEGFR-2 inhibitors. The pyridine, methylamine carbonyl pyridine and pivaloyl amide pyridine were introduced as novel hinge binding fragment. The majority of title compounds displayed potent VEGFR-2 inhibition. In particular, L1, L9, W14 and W15 exhibited significant enzymatic inhibitory activity with IC50 values of 0.36nM, 0.22nM, 0.15nM and 0.14nM. Compounds L1, L9 and W15 displayed potent antiproliferative activity against A549 and SMMC-7721 cells. SAR study suggested that incorporation of 3-trifluoromethyl and methylamine carbonyl on terminal pyridine could improve VEGFR-2 inhibitory activity. Molecular docking illustrated that urea moiety formed two critical hydrogen bonds with the DFG residues of VEGFR-2. The results indicated that these biphenyl-aryl ureas could serve as promising lead compounds for further optimization.

Discovery of biphenyl-based VEGFR-2 inhibitors. Part 3: design, synthesis and 3D-QSAR studies.

VEGFR-2 plays an essential role in angiogenesis and is a central target for anticancer drug discovery. In order to develop novel VEGFR-2 inhibitors, we designed and synthesized 33 biphenyl amides based on our previously reported lead compound. The biological results indicated that four compounds (18b, 20e, 20h and 20j) are potent VEGFR-2 inhibitors which are comparable to positive control. Compound 18b displayed the most potent VEGFR-2 inhibition with IC50 value of 2.02nM. Moreover, it exhibited promising antiproliferative activity against MCF-7 and SMMC-7721 cells with IC50 values of 1.47µM and 5.98µM, respectively. Molecular docking and 3D-QSAR studies were also carried out. The results indicated that these biphenyl amides could serve as promising leads for further optimization as novel VEGFR-2 inhibitors.

Preparation and cellular targeting study of VEGF-conjugated PLGA nanoparticles.

Vascular endothelial growth factor receptor (VEGFR) is over-expressed on a variety of tumour cells and tumour neovasculature, and so becomes well-documented target for cancer treatment. This study was designed to evaluate the cellular targeting and anti-tumor potency of VEGF-conjugated nanoparticles (VEGF-NPs). The poly-lactic-co-glycolic acid nanoparticles were prepared using the emulsion-solvent evaporation method and the VEGF was conjugated on surface of nanoparticles by covalent coupling method. The obtained particles were found to be of spherical shape exhibiting a size of 710 nm and VEGF conjugation efficiency was 16.6%. The results in vitro test showed that VEGF-NPs were more associated to Human Umbilical Vein Endothelial Cells by binding to VEGFR. In vitro cell proliferation test, IC50 showed the superior antiproliferative activity of paclitaxel-loaded VEGF-NPs over unconjugated nanoparticles and native paclitaxel due to higher cellular association on tumour cells. So, the VEGF-NPs offer a promising active targeting carrier for tumour selective treatment.

Biphenyl derivatives incorporating urea unit as novel VEGFR-2 inhibitors: design, synthesis and biological evaluation.

A series of novel biphenyl urea derivates were synthesized and investigated for their potential to inhibit vascular endothelial growth factor receptor-2 (VEGFR-2). In particular, A7, B3 and B4 displayed significant enzymatic inhibitory activities, with IC50 values of 4.06, 4.55 and 5.26 nM. Compound A7 exhibited potent antiproliferative activity on several cell lines. SAR study suggested that the introduction of methyl at ortho-position of the biphenyl urea and tertiary amine moiety could improve VEGFR-2 inhibitory activity and antitumor effects. Molecular docking indicated that the urea moiety formed four hydrogen bonds with DFG residue. These biphenyl ureas could serve as promising lead compounds for further optimization.

Discovery of novel Bcr-Abl inhibitors targeting myristoyl pocket and ATP site.

Bcr-Abl plays an essential role in the pathogenesis and development of chronic myeloid leukaemia (CML). Inhibition of Bcr-Abl has great potential for therapeutic intervention in CML. In order to obtain novel and potent Bcr-Abl inhibitors, twenty seven 4,6-disubstituted pyrimidines were synthesized and evaluated herein. The biological results indicated that four compounds of them (C4, C5, C16, and C23) were potent Bcr-Abl inhibitors which were comparable to positive control. Moreover, C4 and C5 displayed promising antiproliferative activity against K562 cells. The results suggested that these 4,6-disubstituted pyrimidines could serve as promising leads for further optimization of Bcr-Abl inhibitors.

Search for novel histone deacetylase inhibitors. Part II: design and synthesis of novel isoferulic acid derivatives.

Previously, we described the discovery of potent ferulic acid-based histone deacetylase inhibitors (HDACIs) with halogeno-acetanilide as novel surface recognition moiety (SRM). In order to improve the affinity and activity of these HDACIs, twenty seven isoferulic acid derivatives were described herein. The majority of title compounds displayed potent HDAC inhibitory activity. In particular, IF5 and IF6 exhibited significant enzymatic inhibitory activities, with IC50 values of 0.73 ± 0.08 and 0.57 ± 0.16 µM, respectively. Furthermore, these compounds showed moderate antiproliferative activity against human cancer cells. Especially, IF6 displayed promising profile as an antitumor candidate with IC50 value of 3.91 ± 0.97 µM against HeLa cells. The results indicated that these isoferulic acid derivatives could serve as promising lead compounds for further optimization.

Performance evaluation of a newly developed 2019-nCoV nucleic acid detection kit based on Ion Proton sequencing platform and its comparison with the MGI Tech (DNBSEQ-G99) platform.

PURPOSE: To evaluate the performance of a newly developed 2019-nCoV nucleic acid detection kit based on Ion Proton sequencing platform and make comparation with MGI Tech (DNBSEQ-G99) platform. METHODS: References and clinical samples were used to evaluate the precision, agreement rate, limit of detection (LOD), anti-interference ability and analytical specificity. Twenty-seven clinical specimens were used to make comparison between two platforms. RESULTS: The kit showed good intra-assay, inter-assay, inter-day precision between different operators and laboratories, fine agreement rate with references, a relatively low LOD of 1 × 103 copies/ml, anti-interference capability of 5 % whole blood and 1mg/ml mucin and no cross reaction with twenty-nine common clinical pathogens. Consistency of variant classification was observed between two platforms. The WGS from Ion Proton tended to have higher coverage and less missing data. CONCLUSIONS: The newly developed kit has shown satisfactory performances and excellent consistency with DNBSEQ-G99, making it a good alternative choice clinically.

Unveiling hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in Fructus Psoraleae by integrating UPLC-Q-TOF-MS and high content analysis.

ETHNOPHARMACOLOGICAL RELEVANCE: Fructus Psoraleae (FP), the dried and ripe fruit of Cullen corylifolium (L.) Medik., is widely used due to its various clinical pharmacological effects, but its hepatotoxicity restricts its clinical application. So far, its hepatotoxic components and their underlying mechanism have not been systematically elucidated. AIM OF THE STUDY: This study was undertaken to reveal the hepatotoxicity distinction of coumarin-related compounds from glycosides to aglycones in FP and elucidate their potential mechanism. METHODS: Rats were administrated with the aqueous extract of Fructus Psoraleae (AEFP), in which eight coumarin-related compounds were focused. Subsequently, compounds exposed in rats' livers were detected by UPLC-Q-TOF-MS, and the identified hepatotoxic compounds were evaluated to elaborate their possible mechanism by the aid of high content analysis (HCA). RESULTS: Eight coumarin-related compounds were identified, among which psoralenoside (PO), isopsoralenoside (IPO), psoralen (P), and isopsoralen (IP) were the principally exposed compounds in rats' livers. Furocoumarinic acid glucoside (FAG), (E)-3-(4-(((2S, 3R, 4S, 5S, 6R)-3,4,5-trihydroxy-6-(hydroxymethyl) tetrahydro-2H-pyran-2-yl) oxy) benzofuran-5-yl) acrylic acid (isofurocoumarinic acid glucoside, IFAG), furocoumarinic acid (FA), and (E)-3-(4-hydroxybenzofuran-5-yl) acrylic acid (isofurocoumarinic acid, IFA) were also detected in low abundance. P, IP, FA, and IFA were identified as the hepatotoxic compounds, while their glycosides were almost non-hepatotoxic. The HCA's results showed that hepatotoxic compounds disrupted the balance in reactive oxygen species (ROS), nuclear area, and mitochondrial membrane potential of HepG2 cells, leading to the occurrence of hepatotoxicity. CONCLUSIONS: P, IP, FA, and IFA were identified as hepatotoxic compounds, from which P and IP were proposed as the important risk components for hepatotoxicity. The conversion from glycosides to aglycones played an essential role in FP-induced hepatotoxicity.

Adaptive Renewal of Mountainous Historical Towns Based on the Stability of the Social Network Structure: A Case Study in Chongqing, China.

The stability of social network structure (SSNS) in historical towns is influenced by changes in built environments and demographic factors. The historical towns in China have evolved into massive rural-urban migration under the rapid urbanization over the past forty years. In this context, many of these historical towns experienced "declining built environment and disintegrating social networks," which does not contribute to the adaptive renewal of the built environment and social networks in historical towns, as well as the psychological health of residents. This article intends to explore the adaptive renewal of the built environment and social networks of historical towns based on the SSNS. Data on "households" and "social ties" (i.e., kinship, geographic, and job relationship) among households were collected via a field survey in seven historical towns in Chongqing, China. K-core models of social network analysis (SNA) were calculated to analyze SSNS. The result shows that the social networks of historical towns with centripetal-shaped structures were more stable than historical towns with divergent-shaped structures. Moreover, spatial layout forms and functions of households might affect the stability of social networks in historical towns. Based on the results of the analysis of SSNS, strategies for adaptive renewal of the built environments and social networks were put forward in two aspects. The built environment, such as the classification of public spaces and service facilities, can be designed based on the k-core indicator for increasing the spatial connection of households in the historical towns. In addition, increased social activities in historical towns with weak SSNS may promote social connection of households, and are also helpful in boosting public health in psychological aspects.

Mechanism of Enhanced Oral Absorption of a Nano-Drug Delivery System Loaded with Trimethyl Chitosan Derivatives.

Introduction: In the previous study, nanoparticles coated with trimethyl chitosan (TMC) derivatives (PPTT-NPs) could promote the oral bioavailability of panax notoginseng saponins (PNS). Herein, we chose PPTT-NPs as a model drug to study the property and mechanism of intestinal absorption in vitro and in vivo. Methods: The stability of PPTT-NPs was evaluated using simulated gastric fluid and simulated intestinal fluid. The uptake and transport of PPTT-NPs were investigated in Caco-2 and Caco-2&HT29 co-culture cells. The biosafety, intestinal permeability, adhesion, and absorption mechanism of PPTT-NPs were investigated using SD rats in vivo. The live imaging and biodistribution of PPTT-NPs were observed by IVIS. Furthermore, the effects on CYP3A4 of PPTT-NPs were investigated using testosterone as the probe substrate. Results: The results of the stability assay showed that PPTT-NPs had a strong tolerance to the pH and digestive enzymes in the gastrointestinal environment. In vitro cell experiments showed that the uptake of drugs exhibited a time-dependent. When the ratio of TMC-VB12 and TMC-Cys was 1:3, the uptake capacity of PPTT-NPs was the highest. PPTT-NPs could enhance the paracellular transport of drugs by reversibly opening a tight junction. Animal experiments demonstrated that PPTT-NPs have good biological safety. PPTT-NPs had good adhesion and permeability to small intestinal mucosa. Meanwhile, PPTT-NPs needed energy and various protein to participate in the uptake of drugs. The live imaging of NPs illustrated that PPTT-NPs could prolong the residence time in the intestine. Moreover, TMC-VB12 and TMC-Cys could reduce the metabolism of drugs by inhibiting CYP3A4 to a certain extent. Conclusion: The results show that TMC-VB12 and TMC-Cys are effective in the transport of PPTT-NPs. PPTT-NPs can increase the intestinal adhesion of drugs and exert high permeation by intestinal enterocytes which demonstrate significant and efficient potential for oral delivery of the BCS III drugs.