Human Adipose Tissue Lysate-Based Hydrogel for Lasting Immunomodulation to Effectively Improve Spinal Cord Injury Repair.

The long-term inflammatory microenvironment is one of the main obstacles to inhibit acute spinal cord injury (SCI) repair. The natural adipose tissue-derived extracellular matrix hydrogel shows effective anti-inflammatory regulation because of its unique protein components. However, the rapid degradation rate and removal of functional proteins during the decellularization process impair the lasting anti-inflammation function of the adipose tissue-derived hydrogel. To address this problem, adipose tissue lysate provides an effective way for SCI repair due to its abundance of anti-inflammatory and nerve regeneration-related proteins. Thereby, human adipose tissue lysate-based hydrogel (HATLH) with an appropriate degradation rate is developed, which aims to in situ long-term recruit and induce anti-inflammatory M2 macrophages through sustainedly released proteins. HATLH can recruit and polarize M2 macrophages while inhibiting pro-inflammatory M1 macrophages regardless of human or mouse-originated. The axonal growth of neuronal cells also can be effectively improved by HATLH and HATLH-induced M2 macrophages. In vivo experiments reveal that HATLH promotes endogenous M2 macrophages infiltration in large numbers (3.5 × 105/100 µL hydrogel) and maintains a long duration for over a month. In a mouse SCI model, HATLH significantly inhibits local inflammatory response, improves neuron and oligodendrocyte differentiation, enhances axonal growth and remyelination, as well as accelerates neurological function restoration.

EB2 promotes hepatocellular carcinoma proliferation and metastasis via MAPK/ERK pathway by modulating microtubule dynamics.

Metastasis is the main cause of poor postoperative survival of hepatocellular carcinoma (HCC) patients. Cytoskeleton rearrangement is a key event in cancer metastasis. However, the significance of microtubule (MT), one of the core components of cytoskeleton, in this process is only beginning to be revealed. Here, we find that the MT dynamics regulator end-binding protein 2 (EB2) is highly expressed in HCC and predicts poor prognosis of HCC patients. Functional studies show that EB2 overexpression promotes HCC proliferation, invasion and metastasis in vitro and in vivo, while EB2 knockdown has opposite results. Mechanistically, EB2 mediates MTs destabilization, increases Src (Src proto-oncogene non-receptor tyrosine kinase) activity, and thus facilitates extracellular signal-regulated kinase (ERK) signaling activation, which could in turn promote EB2 expression in HCC, eventually resulting in enhanced HCC proliferation, invasion and metastasis. Furthermore, U0126, a specific ERK inhibitor, could effectively inhibit EB2-mediated HCC proliferation and metastasis in vitro and in vivo. In conclusion, EB2 coordinates MT cytoskeleton and intracellular signal transduction, forming an EB2-MT-ERK positive feedback loop, to facilitate HCC proliferation, invasion and metastasis. EB2 could serve as a promising prognostic biomarker and potential therapeutic target for HCC; HCC patients with high EB2 expression may benefit from treatment with ERK inhibitors.

HEG1 indicates poor prognosis and promotes hepatocellular carcinoma invasion, metastasis, and EMT by activating Wnt/ß-catenin signaling.

Heart development protein with EGF-like domains 1 (HEG1) plays critical roles in embryo development and angiogenesis, which are closely related to tumor progression. However, the role of HEG1 in hepatocellular carcinoma (HCC) remains unknown. In the present study, we explored the clinical significance, biological function and regulatory mechanisms of HEG1 in HCC and found that HEG1 is significantly up-regulated in HCC cell lines and primary tumor samples. Additionally, high HEG1 expression is correlated with aggressive clinicopathological features. Patients with high HEG1 expression had shorter overall survival (OS) and disease-free survival (DFS) than those with low HEG1 expression, which indicated that HEG1 is an independent factor for poor prognosis. Lentivirus-mediated HEG1 overexpression significantly promotes HCC cell migration, invasion and epithelial-mesenchymal transition (EMT) in vitro and promotes intrahepatic metastasis, lung metastasis and EMT in vivo Opposing results are observed when HEG1 is silenced. Mechanistically, HEG1 promotes ß-catenin expression and maintains its stability, leading to intracellular ß-catenin accumulation, ß-catenin nuclear translocation and Wnt signaling activation. Loss- and gain-of-function assays further confirmed that ß-catenin is essential for HEG1-mediated promotion of HCC invasion, metastasis and EMT. In conclusion, HEG1 indicates poor prognosis; plays important roles in HCC invasion, metastasis and EMT by activating Wnt/ß-catenin signaling; and can serve as a potentially valuable prognostic biomarker and therapeutic target for HCC.

Selective and Real-Time Detection of Nitric Oxide by a Two-Photon Fluorescent Probe in Live Cells and Tissue Slices.

Nitric oxide (NO) is an important signaling molecule involved in many physiological and pathological processes. To understand these NO-mediated processes, it is a key to develop rapid and specific detection methods for NO. In the past 2 decades, numerous excellent fluorescent probes for NO have been designed; however, it still remains limitations such as slow response, low selectivity, and short excitation wavelength (<600 nm). In this Article, a two-photon fluorescent probe, NO-QA5, has been developed with 3-dimethylaminophenyl linking at the 6-position of 5-aminoquinoline as both the active site and prefluorophore for detection of NO. The nonfluorescent NO-QA5 can fast react with NO via a diazonium intermediate to generate two azoic regioisomers, one of which exhibits intramolecular charge transfer (ICT) emission, and two-photon absorption behavior (Î´Φ = 57 GM), giving a turn-on fluorescence rapid response. The sensing reaction is pH-insensitive in the range of 6-11 and highly selective and well sensitive (LOD = 15 nM), possible undergoing the same intermediate diazonium with the reaction under diazotization condition (NaNO2/HCl). Also, as a nitrite fluorescent probe NO-QA5 exhibits highly sensitive (LOD = 7 nM). Therefore, NO-QA5 can serve as a dual functional fluorescent probe for NO and NO2-. Furthermore, NO-QA5 as a specific imaging agent has been demonstrated by achieving both exogenous and endogenous detections of NO in living cells under both one- and two-photon excitation and high resolution in tissue slices under two-photon excitation.

CD4+CD25+ regulatory T cells decreased future liver remnant after associating liver partition and portal vein ligation for staged hepatectomy.

BACKGROUND: Associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) is an innovative surgical approach for the treatment of massive hepatocellular carcinoma (HCC), the key to successful planned stage 2 ALPPS is future liver remnant (FLR) volume growth, but the exact mechanism has not been elucidated. The correlation between regulatory T cells (Tregs) and postoperative FLR regeneration has not been reported. AIM: To investigate the effect of CD4+CD25+ Tregs on FLR regeneration after ALPPS. METHODS: Clinical data and specimens were collected from 37 patients who developed massive HCC treated with ALPPS. Flow cytometry was performed to detect changes in the proportion of CD4+CD25+ Tregs to CD4+ T cells in peripheral blood before and after ALPPS. To analyze the relationship between peripheral blood CD4+CD25+ Treg proportion and clinicopathological information and liver volume. RESULTS: The postoperative CD4+CD25+ Treg proportion in stage 1 ALPPS was negatively correlated with the amount of proliferation volume, proliferation rate, and kinetic growth rate (KGR) of the FLR after stage 1 ALPPS. Patients with low Treg proportion had significantly higher KGR than those with high Treg proportion (P = 0.006); patients with high Treg proportion had more severe postoperative pathological liver fibrosis than those with low Treg proportion (P = 0.043). The area under the receiver operating characteristic curve between the percentage of Tregs and proliferation volume, proliferation rate, and KGR were all greater than 0.70. CONCLUSION: CD4+CD25+ Tregs in the peripheral blood of patients with massive HCC at stage 1 ALPPS were negatively correlated with indicators of FLR regeneration after stage 1 ALPPS and may influence the degree of fibrosis in patients' livers. Treg percentage was highly accurate in predicting the FLR regeneration after stage 1 ALPPS.

Change of tumor-infiltrating lymphocyte of associating liver partition and portal vein ligation for staged hepatectomy for hepatocellular carcinoma.

BACKGROUND: The role of tumor-infiltrating lymphocytes (TILs) in the growth and progression of hepatocellular carcinoma (HCC) has attracted widespread attention. AIM: To evaluate the feasibility of associating liver partition and portal vein ligation for staged hepatectomy (ALPPS) for massive HCC by exploring the role of TIL in the tumor microenvironment. METHODS: Fifteen massive HCC patients who underwent ALPPS treatment and 46 who underwent hemi-hepatectomy were selected for this study. Propensity score matching was utilized to match patients in ALPPS and hemi-hepatectomy groups (1:1). Quantitative analysis of TILs in tumor and adjacent tissues between the two groups was performed by immunofluorescence staining and further analyses with oncological characteristics. In the meantime, trends of TILs in peripheral blood were compared between the two groups during the perioperative period. RESULTS: Continuous measurement of tumor volume and necrosis volume showed that the proportion of tumor necrosis volume on the seventh day after stage-I ALPPS was significantly higher than the pre-operative value (P = 0.024). In the preoperative period of stage-I ALPPS, the proportion of tumor necrosis volume in the high CD8+ T cell infiltration group was significantly higher than that in the low group (P = 0.048). CONCLUSION: TIL infiltration level maintained a dynamic balance during the preoperative period of ALPPS. Compared with right hemi-hepatectomy, the ALPPS procedure does not cause severe immunosuppression with the decrease in TIL infiltration and pathological changes in immune components of peripheral blood. Our results suggested that ALPPS is safe and feasible for treating massive HCC from the perspective of immunology. In addition, high CD8+ T cell infiltration is associated with increasing tumor necrosis in the perioperative period of ALPPS.

Protein Binding Affinity of Polymeric Nanoparticles as a Direct Indicator of Their Pharmacokinetics.

Polymeric nanoparticles (NPs) are an important category of drug delivery systems, and their in vivo fate is closely associated with delivery efficacy. Analysis of the protein corona on the surface of NPs to understand the in vivo fate of different NPs has been shown to be reliable but complicated and time-consuming. In this work, we establish a simple approach for predicting the in vivo fate of polymeric NPs. We prepared a series of poly(ethylene glycol)-block-poly(d,l-lactide) (PEG-b-PLA) NPs with different protein binding behaviors by adjusting their PEG densities, which were determined by analyzing the serum protein adsorption. We further determined the protein binding affinity, denoted as the equilibrium association constant (KA), to correlate with in vivo fate of NPs. The in vivo fate, including blood clearance and Kupffer cell uptake, was studied, and the maximum concentration (Cmax), the area under the plasma concentration-time curve (AUC), and the mean residence time (MRT) were negatively linearly dependent, while Kupffer cell uptake was positively linearly dependent on KA. Subsequently, we verified the reliability of the approach for in vivo fate prediction using poly(methoxyethyl ethylene phosphate)-block-poly(d,l-lactide) (PEEP-b-PLA) and poly(vinylpyrrolidone)-block-poly(d,l-lactide) (PVP-b-PLA) NPs, and the linear relationship between the KA value and their PK parameters further suggests that the protein binding affinity of polymeric NPs can be a direct indicator of their pharmacokinetics.

[Assessment of enhancement release of Oncorhynchus keta in Suifen River, Northeast China]. / 绥芬河大麻哈鱼增殖放流效果评估.

To evaluate the effects of enhancement release of Chum salmon (Oncorhynchus keta) in Suifen River, the homing Chum salmon was monitored in Dongning section of Suifen River from 2012 to 2017. A total of 462 samples were collected, 41 samples out of which were tagged indivi-duals which were cut off adipose fin before they were released. The recapture rate and the effects of Chum salmon enhancement release were analyzed and evaluated based on the releasing information. The results showed that the entire recapture rate of Chum salmon from 2010 to 2012 was 0.295%, and the input-output ratio of enhancement release was 1:2.87. Both the tagged and non-tagged groups were composed of 1+ to 5+ age individuals, with the average age being 3.93 and 3.63 years, respectively. The fork length at 50% individuals reached sexual maturity (L50) was estimated using a logistic moderating function, which was 53.13 cm and 49.89 cm for tagged and non-tagged groups, respectively. Results from ARSS analysis showed that there was no significant difference in fork length growth between tagged and non-tagged groups, but a significant difference in sexual maturity ratio. Our results confirmed the positive effects of enhancement release on recovery of Chum salmon resource and provided suggestions for the enhancement release efforts.

Incorporation of a rhodamine B conjugated polymer for nanoparticle trafficking both in vitro and in vivo.

Polymeric nanoparticles as drug delivery systems have the potential to improve the therapeutic efficacy and reduce the toxicity of chemotherapeutic drugs by enhancing the drug selectivity in vivo. The efficacy is directly dependent on the polymeric nanoparticles' in vivo fate. Therefore, it is very important to develop a method to stably label the polymeric nanoparticles for detecting the in vivo fate. Here, we report a method to stably label self-assembled nanoparticles by the incorporation of rhodamine B-conjugated poly(ε-caprolactone) (PCL-RhoB). Only 1% of PCL-RhoB was released from the RhoB-labeled polymeric nanoparticles (RhoB-PNPs) in phosphate buffer within 12 hours, which suggested that the signal of PCL-RhoB can be used to represent the behaviors of polymeric nanoparticles both in vitro and in vivo. PCL-RhoB could be effectively extracted and quantitatively detected by ultra-high-performance liquid chromatography (UPLC) in various media, such as PBS, a cell culture medium containing 10% FBS (pH = 7.4 and pH = 6.8), mouse serum, simulated intestinal fluid and cell or tissue lysis. The intracellular contents of PCL-RhoB in MDA-MB-231 cells detected by UPLC were linearly correlated to the concentration of the RhoB-PNPs. In addition, the contents of PCL-RhoB in plasma and the spleen were proportional to the injected dose of RhoB-PNPs in vivo. As an application example, the pharmacokinetics and biodistribution of the nanoparticles over time in vivo were analyzed following intravenous injection to confirm the feasibility of this method.

Downregulation of castor zinc finger 1 predicts poor prognosis and facilitates hepatocellular carcinoma progression via MAPK/ERK signaling.

BACKGROUND: Castor zinc finger 1 (CASZ1) plays critical roles in various biological processes and pathologic conditions, including cancer. However, the prognostic importance and biologic functions of CASZ1 in hepatocellular carcinoma (HCC) are still unclear. METHODS: qRT-PCR, western blot and immunohistochemistry analyses were used to determine CASZ1 expression in HCC samples and cell lines. The clinical significance of CASZ1 was assessed in two independent study cohorts containing 232 patients with HCC. A series of in vitro and in vivo experiments were performed to explore the role and molecular mechanism of CASZ1 in HCC progression. RESULTS: Here we report that CASZ1 expression was downregulated in HCC tissues and cell lines. Low CASZ1 expression was closely correlated with aggressive clinicopathological features, poor clinical outcomes and early recurrence of HCC patients. Moreover, overexpression of CASZ1 in HCCLM3 cells significantly inhibited cell proliferation, migration, invasion in vitro and tumor growth and metastasis in vivo, whereas silencing CASZ1 significantly enhanced the above abilities of PLC/PRF/5 cells. Further mechanism study indicated that these phenotypic changes were mediated by MAPK/ERK signaling pathway and involved altered expression of MMP2, MMP9 and cyclinD1. Finally, we proved that CASZ1 exerted its tumor-suppressive effect by directly interacting with RAF1 and reducing the protein stability of RAF1. CONCLUSIONS: Our study for the first time demonstrated that CASZ1 is a tumor suppressor in HCC, which may serve as a novel prognostic predictor and therapeutic target for HCC patients.

Delivery of tacrolimus with cationic lipid-assisted nanoparticles for ulcerative colitis therapy.

Oral drug delivery with nanoparticles has demonstrated great potential for drugs with poor bioavailability. Efficient delivery is possible by overcoming both the mucus and epithelial barrier of the gastrointestinal tract (GIT). Cationic lipid-assisted nanoparticles (CLANs), which are composed of amphiphilic block copolymers and cationic lipids, have been well studied and have been proved beneficial for drug delivery. In this study, CLANs prepared by poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) and 1,2-dioleoyl-3-trimethylammonium-propanechloride (DOTAP) or N,N-bis(2-hydroxyethyl)-N-methyl-N-(2-cholesteryloxycarbonyl aminoethyl)ammoniumbromide (BHEM-Chol) were used for oral delivery of tacrolimus (FK506) for ulcerative colitis treatment. The average size of these nanoparticles is around 110 nm and the zeta-potential is 35 mV. These nanoparticles maintained their size in buffer solutions of pH 1.2 and 6.8, and slowly release the encapsulated drug. CLANs can be accumulated in the colon and transported through the epithelium in the colitis model by dextran sulfate sodium salt (DSS), leading to attenuation of DSS-induced colitis.

The effect of surface poly(ethylene glycol) length on in vivo drug delivery behaviors of polymeric nanoparticles.

Engineering nanoparticles of reasonable surface poly(ethylene glycol) (PEG) length is important for designing efficient drug delivery systems. Eliminating the disturbance by other nanoproperties, such as size, PEG density, etc., is crucial for systemically investigating the impact of surface PEG length on the biological behavior of nanoparticles. In the present study, nanoparticles with different surface PEG length but similar other nanoproperties were prepared by using poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-b-PCL) copolymers of different molecular weights and incorporating different contents of PCL3500 homopolymer. The molecular weight of PEG block in PEG-PCL was between 3400 and 8000 Da, the sizes of nanoparticles were around 100 nm, the terminal PEG density was controlled at 0.4 PEG/nm2 (or the frontal PEG density was controlled at 0.16 PEG/nm2). Using these nanoproperties well-designed nanoparticles, we demonstrated PEG length-dependent changes in the biological behaviors of nanoparticles and exhibited nonmonotonic improvements as the PEG molecular weight increased from 3400 to 8000 Da. Moreover, under the experimental conditions, we found nanoparticles with a surface PEG length of 13.8 nm (MW = 5000 Da) significantly decreased the absorption with serum protein and interaction with macrophages, which led to prolonged blood circulation time, enhanced tumor accumulation and improved antitumor efficacy. The present study will help to establish a relatively precise relationship between surface PEG length and the in vivo behavior of nanoparticles.

Macrophage-Specific in Vivo Gene Editing Using Cationic Lipid-Assisted Polymeric Nanoparticles.

The CRISPR/Cas9 gene editing technology holds promise for the treatment of multiple diseases. However, the inability to perform specific gene editing in targeted tissues and cells, which may cause off-target effects, is one of the critical bottlenecks for therapeutic application of CRISPR/Cas9. Herein, macrophage-specific promoter-driven Cas9 expression plasmids (pM458 and pM330) were constructed and encapsulated in cationic lipid-assisted PEG-b-PLGA nanoparticles (CLAN). The obtained nanoparticles encapsulating the CRISPR/Cas9 plasmids were able to specifically express Cas9 in macrophages as well as their precursor monocytes both in vitro and in vivo. More importantly, after further encoding a guide RNA targeting Ntn1 (sgNtn1) into the plasmid, the resultant CLANpM330/sgNtn1 successfully disrupted the Ntn1 gene in macrophages and their precursor monocytes in vivo, which reduced expression of netrin-1 (encoded by Ntn1) and subsequently improved type 2 diabetes (T2D) symptoms. Meanwhile, the Ntn1 gene was not disrupted in other cells due to specific expression of Cas9 by the CD68 promoter. This strategy provides alternative avenues for specific in vivo gene editing with the CRISPR/Cas9 system.

The effect of surface charge on oral absorption of polymeric nanoparticles.

Surface charge plays an important role in determining the interactions of nanoparticles with biological components. Substantial studies have demonstrated that surface charge affects the fate of nanoparticles after intravenous administration; however, few studies have investigated the effect of surface charge on the bioavailability and absorption of nanoparticles after oral administration. In this study, polymeric nanoparticles with a similar particle size and surface polyethylene glycol (PEG) density, but with varying surface charges (positive, negative and neutral), were developed to study the effect of surface charge on the oral absorption of polymeric nanoparticles. The nanoparticles were constructed from polyethylene glycol-block-polylactic acid (PEG-PLA) with the incorporation of lipid components with different charges. Our results suggested that the positive surface charge facilitated the cellular uptake and transport of nanoparticles through both Caco-2 cells in vitro and small intestinal epithelial cells in vivo. The positively charged nanoparticles showed a favorable distribution in the small intestine, and significantly improved the oral bioavailability. This study presents valuable information towards the design of nanoparticles for improved oral drug delivery.

Oncogenic function and prognostic significance of Abelson interactor 1 in hepatocellular carcinoma.

Aberrant expression of Abelson interactor 1 (ABI1) has been reported in multiple cancers. However, its clinical significance and potential biological roles in hepatocellular carcinoma (HCC) have not been fully elucidated. In this study, we found that ABI1 was obviously upregulated in HCC tissues compared with non-tumor tissues. Moreover, high ABI1 expression was significantly correlated with tumor size (P=0.041), tumor number (P<0.001), tumor encapsulation (P<0.001) and BCLC stage (P=0.010). Importantly, Kaplan-Meier survival analysis showed that increased ABI1 expression predicted shorter overall survival time (P<0.001) and a higher tendency of tumor recurrence (P=0.001) in HCC patients. Multivariate Cox regression analysis further confirmed high ABI1 expression was an independent predictor for both overall survival (HR=1.795, P=0.025) and early recurrence (HR=1.893, P=0.012) after surgical resection. Furthermore, in vitro studies indicated that overexpression of ABI1 induced an increase in cell proliferation, migration and invasion of HCC cells, whereas knockdown of ABI1 did the opposite. Xenograft mouse models verified the promoting effects of ABI1 on HCC growth and lung metastasis in vivo. Collectively, our findings indicated that ABI1 contributes to the development and progression of HCC as an oncogene and may serve as a valuable prognostic marker for HCC patients.

Red fluorescent probes based on a Bodipy analogue for selective and sensitive detection of selenols in solutions and in living systems.

Selenocysteine (Sec), which is a biological selenol incorporated into selenoproteins specifically, plays vital roles in physiological processes and cancer treatment. However, there are limited fluorescent probes for selective detection of Sec and in only one case is a near-infrared (IR) fluorescent probe applied in biological imaging of Sec in living animals. In this work, we have synthesized a new fluorophore, boron-dibenzopyrromethene (B-Bodipy), with an absorption maximum at 650-660 nm, and constructed two deep red fluorescent probes, Sel-p1 and Sel-p2, which are two ethers composed of a 2,4-dinitrobenzenoxy and B-Bodipy moiety. Experiments in solution show that the two probes can react effectively with selenols to release the fluorophore via aromatic nucleophilic substitution (SNAr), with a low limit of detection (16 nM and 9 nM), high selectivity and excellent photostability. The potential application for the detection of Sec in cells has been demonstrated by cell imaging experiments of Sel-p2, including detection of exogenous Sec and selenite-induced Sec in living cells. Furthermore, Sel-p2 as a red fluorescent probe can achieve the detection of Sec in animals by mice imaging experiments.

Overcoming tumor resistance to cisplatin by cationic lipid-assisted prodrug nanoparticles.

Chemotherapy resistance has become a major challenge in the clinical treatment of lung cancer which is the leading cancer type for the estimated deaths. Recent studies have shown that nanoparticles as drug carriers can raise intracellular drug concentration by achieving effectively cellular uptake and rapid drug release, and therefore reverse the acquired chemoresistance of tumors. In this context, nanoparticles-based chemotherapy represents a promising strategy for treating malignancies with chemoresistance. In the present study, we developed cationic lipid assisted nanoparticles (CLAN) to deliver polylactide-cisplatin prodrugs to drug resistant lung cancer cells. The nanoparticles were formulated through self-assembly of a biodegradable poly(ethylene glycol)-block-poly(lactide) (PEG-PLA), a hydrophobic polylactide-cisplatin prodrug, and a cationic lipid. The cationic nanoparticles were proven to significantly improve cell uptake of cisplatin, leading to an increased DNA-Pt adduct and significantly promoted DNA damage in vitro. Moreover, our study reveals that cationic nanoparticles, although are slightly inferior in blood circulation and tumor accumulation, are more effective in blood vessel extravasation. The CLANs ultimately enhances the cellular drug availability and leads to the reversal of cisplatin resistance.

[Exogenous Sr2+ sedimentation on otolith of chum salmon embryos].

To explore the exogenous Sr2+ sedimentation on otolith of chum salmon embryos, chum salmon embryos were exposed to culture water contained Sr2+ at Sr2+ concentration of 50, 100, 200 or 400 mg . L-1 for 48 h to imitate Sr2+ sedimentation. After a culturing period of 12 d and 100 d, the otoliths of the chum salmon were taken to detect exogenous Sr2+ sedimentation with electro-probe microanalyzer (EPMA). The results showed that obvious deep red strontium signatures were produced in the otolith of chum salmon at different concentrations of Sr2+. The mean and extreme values of peak strontium area were not stable for the same Sr2+ dose, but the lowest of all the peak values was 35.1 times as much as that of control. Overall, the strontium value increased with the increase of Sr2+concentration. The strontium peak had no signs of abating after a culture period of 100 d. The results also showed that strontium was gradually deposited in the otolith, and had obvious hysteresis to immersion. Strontium sedimentation could also return to a normal level after the peak. These characteristics accorded exactly with the requirement of discharge tag technology, which indicated that exogenous Sr2+ was suitable in the marking of salmon otolith.

Regulating the surface poly(ethylene glycol) density of polymeric nanoparticles and evaluating its role in drug delivery in vivo.

Poly(ethylene glycol) (PEG) is usually used to protect nanoparticles from rapid clearance in blood. The effects are highly dependent on the surface PEG density of nanoparticles. However, there lacks a detailed and informative study in PEG density and in vivo drug delivery due to the critical techniques to precisely control the surface PEG density when maintaining other nano-properties. Here, we regulated the polymeric nanoparticles' size and surface PEG density by incorporating poly(ε-caprolactone) (PCL) homopolymer into poly(ethylene glycol)-block-poly(ε-caprolactone) (PEG-PCL) and adjusting the mass ratio of PCL to PEG-PCL during the nanoparticles preparation. We further developed a library of polymeric nanoparticles with different but controllable sizes and surface PEG densities by changing the molecular weight of the PCL block in PEG-PCL and tuning the molar ratio of repeating units of PCL (CL) to that of PEG (EG). We thus obtained a group of nanoparticles with variable surface PEG densities but with other nano-properties identical, and investigated the effects of surface PEG densities on the biological behaviors of nanoparticles in mice. We found that, high surface PEG density made the nanoparticles resistant to absorption of serum protein and uptake by macrophages, leading to a greater accumulation of nanoparticles in tumor tissue, which recuperated the defects of decreased internalization by tumor cells, resulting in superior antitumor efficacy when carrying docetaxel.

[Diet composition and transition of clearhead icefish(Protosalanx hyalocranius)in Lake Xingkai].

Diet compositions of alien clearhead icefish(Protosalanx hyalocranius)in Lake Xingkai were investigated monthly from June 2010 through January 2011. Protosalanx hyalocranius preyed mainly on cladoceran, copepoda, shrimp, and larvae or juvenile fish. In June, P. Hyalocranius were smaller than 60 mm standard length(SL), and their diets were composed of zooplankton only. In July, fish began to appear infrequently in the diet of P. Hyalocranius larger than 60 mm SL, and by August fish was occurring in the diets of P. hyalocranius larger than 80 mm, 100 mm in September, and 120 mm in October and thereafter, respectively. The increase in the minimum SL of P. hyalocranius preying on fish within a given season reflects changes in resource availability, largely attributed to the corresponding increase in prey fish size as seasons progress. Protosalanx hyalocranius and Hemiculter sp. were the dominant prey fish in the diets of P. hyalocranius.