A possible dose-response equation: Viral load after plasma infusion in COVID-19 patients and anti-SARS-CoV-2 antibody titers in convalescent plasma.

BACKGROUND: Clinical trials of convalescent plasma therapy for coronavirus disease 2019 (COVID-19) are extensive, but the relationship between antibody titers, infused volume of plasma and virus clearance in patients remains unknown. This study proposed a possible estimating equation for clinical use of high antibody titer convalescent plasma. METHODS: A total of 38 patients were recruited in the Guanggu District Maternal and Child Health Hospital of Hubei Province from March 1 to 30, 2020. COVID-19 convalescent plasma was collected and high-titer (≥1:640) anti-S-RBD units used. The SARS-CoV-2 nucleic acid viral load was measured 24 h before and 72 h after convalescent plasma infusion. RESULTS: Convalescent plasma therapy was associated with reduced viral load in patients with moderate and severe severity. The viral negative rate at 72 h was 65.8%. The disappearance of viral nucleic acid in study patients was positively correlated with infuscate antibody titer and volume (r = 0.3375, p = 0.04). A possible estimation equation was as follows: Log10 (Reduction in viral load) = 0.18 + 0.001 × (Log2 S-RBD antibody titer × Plasma infusion volume) (r = 0.424, p = 0.009). In a single case, the viral nucleic acid persisted 14 days after the fourth plasma infusion. CONCLUSIONS: This study proposes a potential dose-response equation that adds a convenient way to estimate the dose of convalescent plasma product. It is beneficial to facilitate the rational allocation of plasma with high antibody titers and provide an individualised use strategy for convalescent plasma therapy.

Structure-switchable aptamer-arranged reconfigurable DNA nanonetworks for targeted cancer therapy.

The structural DNA nanotechnology holds great potential application in bioimaging, drug delivery and cancer therapy. Herein, an intelligent aptamer-incorporated DNA nanonetwork (Apt-Nnes) is demonstrated for cancer cell imaging and targeted drug delivery, which essentially is a micron-scale pattern with the thickness of double-stranded monolayer. Cancer cell-surface receptors can make it perform magical transformation into small size of nanosheet intermediates and specifically enter target cells. The binding affinity of Apt-Nnes is increased by 3-fold due to multivalent binding effect of aptamers and it can maintain the structural integrity in fetal bovine serum (FBS) for 8 h. More interestingly, target cancer cells can cause the structural disassembly, and each resulting unit transports 4963 doxorubicin (Dox) into target cells, causing the specific cellular cytotoxicity. The cell surface receptor-mediated disassembly of large size of DNA nanostructures into small size of fractions provides a valuable insight into developing intelligent DNA nanostructure suitable for biomedical applications.

Precision-Guided Missile-Like DNA Nanostructure Containing Warhead and Guidance Control for Aptamer-Based Targeted Drug Delivery into Cancer Cells in Vitro and in Vivo.

It is crucial to deliver anticancer drugs to target cells with high precision and efficiency. While nanomaterials have been shown to enhance the delivery efficiency once they reach the target, it remains challenging for precise drug delivery to overcome the nonspecific adsorption and off-target effect. To meet this challenge, we report herein the design of a novel DNA nanostructure to act as a DNA nanoscale precision-guided missile (D-PGM) for highly efficient loading and precise delivery of chemotherapeutic agents to specific target cells. The D-PGM consists of two parts: a warhead (WH) and a guidance/control (GC). The WH is a rod-like DNA nanostructure as a drug carrier, whose trunk is a three-dimensionally self-assembled DNA nanoscale architecture from the programmed hybridization among two palindromic DNA sequences in the x-y dimension and two common DNA oligonucleotides in the z direction, making the WH possess a high payload capacity of drugs. The GC is an aptamer-based logic gate assembled in a highly organized fashion capable of performing cell-subtype-specific recognition via the sequential disassembly, mediated by cell-anchored aptamers. Because of the cooperative effects between the WH and the GC, the GC logic gates operate like the guidance and control system in a precision-guided missile to steer the doxorubicin (DOX)-loaded DNA WH toward target cancer cells, leading to selective and enhanced therapeutic efficacy. Moreover, fluorophores attached to different locations of D-PGM and DOX fluorescence dequenching upon release enable intracellular tracing of the DNA nanostructures and drugs. The results demonstrate that by mimicking the functionalities of a military precision-guided missile to design the sequential disassembly of the GC system in multistimuli-responsive fashion, our intrinsically biocompatible and degradable D-PGM can accurately identify target cancer cells in complex biological milieu and achieve active targeted drug delivery. The success of this strategy paves the way for specific cell identity and targeted cancer therapy.

The efficacy and safety of bevacizumab combined with chemotherapy in treatment of HER2-negative metastatic breast cancer: a meta-analysis based on published phase III trials.

Bevacizumab (Bev) combined with chemotherapy significantly improves progression-free survival (PFS) but not overall survival (OS) in patients with human epidermal growth factor receptor 2 (HER2)-negative metastatic breast cancer (MBC). The efficacy and safety depend on the type of chemotherapy combined with Bev. We performed a meta-analysis of phase III trials to evaluate the efficacy and safety of Bev + standard chemotherapy for HER2-negative MBC. The Cochrane Central Register of Controlled Trials, the Cochrane databases, EMBASE, MEDLINE, and ClinicalTrials.gov were analyzed. The primary outcomes included PFS, OS, and toxicity. Event-based hazard ratios (HRs) and relative risks (RRs) were expressed with the 95% confidence intervals (CIs). Four randomized controlled trials consisting of 3082 patients were included. Bev + standard chemotherapy improved PFS (HR 0.70, CI 0.64-0.77, P = 0.000) but had no effect on OS (HR 0.92, CI 0.82-1.02, P = 0.119). Bev + chemotherapy increased the incidence of febrile neutropenia (RR 1.45, CI 1.00 to 2.09, P = 0.048), proteinuria (RR 11.68, CI 3.72-36.70, P = 0.000), sensory neuropathy (RR 1.33, CI 1.05-1.70, P = 0.020), and grade ≥3 hypertension (RR 13.94, CI 7.06-27.55, P = 0.000). No differences in efficacy were observed between Bev + paclitaxel and Bev + capecitabine (Cape), but Bev + Cape increased the incidence of neutropenia. Bev + standard chemotherapy improved PFS in HER2-negative MBC patients. No benefit in OS was observed. Bev + Cape and Bev + paclitaxel had similar treatment efficacy, but Bev + Cape had a higher incidence of neutropenia.

Competitive inhibition of the nondepolarizing muscle relaxant rocuronium on nicotinic acetylcholine receptor channels in the rat superior cervical ganglia.

A number of case reports now indicate that rocuronium can induce a number of serious side effects. We hypothesized that these side effects might be mediated by the inhibition of nicotinic acetylcholine receptors (nAChRs) at superior cervical ganglion (SCG) neurons. Conventional patch clamp recordings were used to study the effects of rocuronium on nAChR currents from enzymatically dissociated rat SCG neurons. We found that ACh induced a peak transient inward current in rat SCG neurons. Additionally, rocuronium suppressed the peak ACh-evoked currents in rat SCG neurons in a concentration-dependent and competitive manner, and it increased the extent of desensitization of nAChRs. The inhibitory rate of rocuronium on nAChR currents did not change significantly at membrane potentials between -70 and -20 mV, suggesting that this inhibition was voltage independent. Lastly, rocuronium preapplication enhanced its inhibitory effect, indicating that this drug might prefer to act on the closed state of nAChR channels. In conclusion, rocuronium, at clinically relevant concentrations, directly inhibits nAChRs at the SCG by interacting with both opened and closed states. This inhibition is competitive, dose dependent, and voltage independent. Blockade of synaptic transmission in the sympathetic ganglia by rocuronium might have potentially inhibitory effects on the cardiovascular system.

Emulsified isoflurane preconditioning protects isolated rat Kupffer cells against hypoxia/reoxygenation-induced injury.

OBJECTIVE: To investigate the protective effect of emulsified isoflurane (EI) preconditioning on isolated rat Kupffer cells (KCs) subjected to hypoxia/reoxygenation (H/R)-induced injury. MATERIALS AND METHODS: KCs were isolated by collagenase digestion and purified by Percoll density gradient centrifugation. Primary cultured KCs were divided into five groups: control, H/R plus 0.1% lipid preconditioning, and H/R plus 0.05%, 0.1% or 0.2% emulsified isoflurane preconditioning groups. H/R was induced by 4 h of hypoxia followed by 6 h of reoxygenation. Reactive oxygen species (ROS) production in the KCs and the concentration of tumor necrosis factor-α (TNF-α) in the KC culture media were measured, and the apoptosis of KCs was assayed concomitantly. RESULTS: ROS and TNF-α production were markedly induced in the H/R + lipid group, and lower in the 0.2% and 0.1% EI groups (P<0.05). The apoptotic rate in the H/R + lipid group was significantly higher than that in the 0.2% and 0.1% EI groups (P<0.05). CONCLUSIONS: Emulsified isoflurane protects isolated rat KCs against H/R induced injury by decreasing the production of ROS and TNF-α and attenuating apoptosis in KCs.

DNA methylation regulator-based signature for predicting clear cell renal cell carcinoma prognosis.

OBJECTIVES: To investigate the role of DNA methylation regulators in the prognosis of clear cell renal cell carcinoma (ccRCC) and to construct a DNA methylation regulator-based signature for predicting patient outcome. METHODS: Data from the TCGA dataset were downloaded and analyzed to identify differentially expressed DNA methylation regulators and their interaction as well as correlation. Consensus clustering was used to establish groups of ccRCC with distinct clinical outcomes. A prognostic signature based on two sets of DNA methylation regulators was established and validated in an independent cohort. RESULTS: Our analysis revealed that the expression levels of DNMT3B, MBD1, SMUG1, DNMT1, DNMT3A, TDG, TET3, MBD2, UHRF2, MBD3, UHRF1, and TET2 were significantly upregulated in ccRCC samples, while UNG, ZBTB4, TET1, ZBTB38, and MECP2 were markedly downregulated. UHRF1 was identified as a hub gene in the DNA methylation regulator interaction network. Significant differences were found regarding overall survival, gender, tumor status, and grade between ccRCC patients in the two risk groups. The prognostic signature, based on two sets of DNA methylation regulators, was an independent prognostic indicator, and these findings were validated in an external, independent cohort. CONCLUSIONS: The study provides evidence that DNA methylation regulators play a significant role in the prognosis of ccRCC and the developed DNA methylation regulator-based signature could effectively predict patient outcome.

Anxiety, depression symptoms, and psychological resilience among hospitalized COVID-19 patients in isolation: A study from Wuhan, China.

OBJECTIVE: To investigate the status of anxiety, depression, and psychological resilience among individuals with COVID-19, and their interrelationships to provide a scientific basis for developing psychological intervention strategies for these patients. METHODS: A total of 126 patients with COVID-19 who were admitted to Wuhan Huoshenshan Hospital were recruited in this study. A comprehensive survey was conducted using a general information questionnaire, the Self-Rating Anxiety Scale, the self-rating depression scale, and the Chinese version of the psychological Connor-Davidson resilience scale; a questionnaire-based survey was conducted. RESULTS: Significant differences in anxiety scores were observed among COVID-19 patients with different education levels and the number of immediate family members. The differences in depression scores were noted among patients of different age groups, and marital statuses were also significant. The total psychological resilience score and the scores of all dimensions are negatively correlated with anxiety and depression. Furthermore, the patient's gender, the number of immediate family members, and the psychological resilience dimensions are associated with the severity anxiety of patients. Patient age and psychological resilience are associated with the depression level of patients. CONCLUSION: Patients with COVID-19 exhibit elevated levels of both anxiety and depression. Notably, psychological resilience emerges as a protective factor against the development of anxiety and depression.

Experimental and constitutive model study on the mechanical properties of a structural plane of a rock mass under dynamic disturbance.

An accurate description of the mechanical properties and deformation characteristics of a structural plane of a rock mass with a large chamber or slope under the ultimate stress with periodic stress disturbances is of great significance to ensure the stability and safety of underground rock engineering. By theoretically analysing the strength effect of a structural plane of a rock mass under dynamic disturbance, a criterion for the occurrence of shear damage on a structural plane of a compressed rock mass under dynamic disturbance is proposed. The results of the cyclic disturbance kinetic test show that there is a disturbance threshold for the shear failure of the structural plane under different disturbance stresses. When the disturbance stress is lower than the disturbance threshold, the cumulative plastic strain stabilizes with an increasing number of cycles; when the disturbance stress is higher than the disturbance threshold, an S-shaped curve of cumulative plastic strain versus the number of cycles is observed, revealing the progressive damage process and mechanism of such a rock structure plane under periodic dynamic disturbance. Based on perturbation concept theory, the relationship between the accumulated plastic strain and the number of cyclic loadings is similar to the relationship between strain and time, the creep curve. A new nonlinear viscous element is proposed, and the nonlinear element and the deformation element considering structural plane closure and sliding are combined with the Burgers model to form an 8-element nonlinear viscoelastic‒plastic creep constitutive model. Using the global optimization algorithm of 1stOpt, model validation and parameter identification are performed on the experimental data, and the results show that the model curve has a very good agreement with the experimental data. The model can accurately reflect the deformation characteristics of a structural plane of a rock mass under periodic dynamic disturbance. These research results provide a new idea for analysing disturbance-induced geohazards.

Failure energy evolution of coal-rock combination with different inclinations.

In this paper, in the deformation and damage process under different confining pressures, the energy evolution characteristics and damage mechanism of coal-rock combinations with different inclination angles are studied. Based on the brittleness indexes of coal rock combinations, the evolution rules between brittleness indexes and the inclination are explored, as well as the confining pressure of coal rock combinations; then, the influence mechanism of the inclination angle of coal rock combinations on the plastic yielding degree, energy dissipation level, crack extension and fracture speed in the pre-peak stage is revealed. The composite specimens are mainly damaged due to oblique shear and accompanied by tensile damage; In the deformation and damage, various energies of coal rock composites are distributed as a negative exponential function of the inclination angle, which is significantly affected by the change of the confining pressure.

Severe versus common COVID-19: an early warning nomogram model.

The wide spread of coronavirus disease 2019 is currently the most rigorous health threat, and the clinical outcomes of severe patients are extremely poor. In this study, we establish an early warning nomogram model related to severe versus common COVID-19. A total of 1059 COVID-19 patients were analyzed in the primary cohort and divided into common and severe according to the guidelines on the Diagnosis and Treatment of COVID-19 by the National Health Commission of China (7th version). The clinical data were collected for logistic regression analysis to assess the risk factors for severe versus common type. Furthermore, 123 COVID-19 patients were reviewed as the validation cohort to assess the performance of this model. Multivariate logistic analysis revealed that age, dyspnea, lymphocyte count, C-reactive protein and interleukin-6 were independent factors for prewarning the severe type occurrence. Then, the early warning nomogram model including these risk factors for inferring the severe disease occurrence out of common type of COVID-19 was constructed. The C-index of this nomogram in the primary cohort was 0.863, 95% confidence interval (CI) (0.836-0.889). Meanwhile, in the validation cohort, the C-index of this nomogram was 0.889, 95% CI (0.828-0.950). In both the primary cohort and validation cohorts, the calibration curve showed good agreement between prediction and actual probability. The early warning model shows that data at the very beginning including age, dyspnea, lymphocyte count, CRP, and IL-6 may prewarn the severe disease occurrence to some extent, which could help clinicians early and timely treatment.

Emulsified isoflurane preconditioning reduces lung injury induced by hepatic ischemia/reperfusion in rats.

OBJECTIVE: To investigate whether emulsified isoflurane preconditioning could reduce lung injury induced by hepatic I/R in rats and its mechanism. MATERIALS AND METHODS: 32 pentobarbital-anesthetized Sprague-Dawley rats were equally randomized into four groups: laparotomy group (Sham group), hepatic I/R and normal saline infusion group (I/R+S group), I/R and lipid vehicle infusion (I/R+V group), or I/R and 8% emulsified isoflurane infusion (I/R+E group) at the rate of 8 ml·kg(-1)·h(-1) for 30 min. Blood supply of the hepatic artery and portal vein to the left and the median liver lobes was occluded for 90 min after 30-min washout time. Reperfusion was allowed to proceed for 4 h before sacrifice of the animals. Lung injury was observed histologically. Neutrophil infiltration and TNF-α concentration in serum and lung were measured. Changes of wet-to-dry weight ratios in lung tissue, ICAM-1 expression and NF-κB activity in lung after hepatic I/R were determined. RESULTS: Compared with I/R+S or I/R+V group, emulsified isoflurane preconditioning reduced hepatic I/R-induced lung histologic injury and inhibited the increase of myeloperoxidase (MPO) activity in the lung tissue markedly (5.5±1.37 and 5.22±1.33 vs 3.81±1.62 U/g, P<0.05). In addition, both serum and lung tissue TNF-α levels were reduced in I/R+E group (104.58±31.40 and 94.60±22.23 vs 72.44±17.28 pg/ml, P<0.05; 393.51±88.22 and 405.46±102.87 vs 292.62±74.56 pg/ml, P<0.01). Emulsified isoflurane preconditioning also inhibited the increase of ICAM-1 expression (0.79±0.17 and 0.84±0.24 vs 0.62±0.21, P<0.05) and NF-κB translocation (4.93±0.48 and 4.76±0.57 vs 4.01±0.86, P<0.05) in the lung tissue markedly. CONCLUSIONS: Emulsified isoflurane preconditioning markedly attenuated hepatic I/R-induced lung injury in rats, which may be hopefully applied to the clinical treatment of organ injury caused by hepatic surgery, transplantation or hemorrhagic shock.

Administration Timing and Efficacy of Tocilizumab in Patients With COVID-19 and Elevated IL-6.

BACKGROUND: Tocilizumab (TCZ), an interleukin-6 receptor antibody, has previously been used for treating patients with the coronavirus disease 2019 (COVID-19), but there is a lack of data regarding the administration timing of TCZ. OBJECTIVES: This study aimed to evaluate the timing and efficacy of TCZ in the treatment of patients with COVID-19. METHODS: Laboratory-confirmed patients with COVID-19 with an elevated interleukin-6 (IL-6) level (>10 pg/ml) were offered TCZ intravenously for compassionate use. Clinical characteristics, laboratory tests, and chest imaging before and after the administration of TCZ were retrospectively analyzed. RESULTS: A total of 58 consecutive patients who met the inclusion criteria and with no compliance to the exclusion criteria were included. Of these 58 patients, 39 patients received TCZ treatment, and 19 patients who declined TCZ treatment were used as the control cohort. In the TCZ-treatment group, 6 patients (15.4%) were in mild condition, 16 (41.0%) were in severe condition, and 17 (43.6%) were in critical condition. After TCZ treatment, the condition of 27 patients (69.2%) improved and 12 (30.8%) died. Compared with the improvement group, patients in the death group had higher baseline levels of IL-6 (P = 0.0191) and procalcitonin (PCT) (P = 0.0003) and lower lymphocyte percentage (LYM) (P = 0.0059). Patients receiving TCZ treatment had better prognoses than those without TCZ treatment (P = 0.0273). Furthermore, patients with a baseline IL-6 level of ≥100 pg/ml in the TCZ-treatment group had poorer clinical outcomes than those with an IL-6 level of <100 pg/ml (P = 0.0051). CONCLUSION: The administration of TCZ in an early stage of cytokine storm (IL-6 level < 100 pg/ml) may effectively improve the clinical prognosis of patients with COVID-19 by blocking the IL-6 signal pathway.

[Increased level of Th17 cells in peripheral blood correlates with the development of hepatocellular carcinoma].

OBJECTIVE: To investigate the potential correlation between the level of Th17 cells in peripheral blood and the development of human hepatocellular carcinoma (HCC). METHODS: Th17 cells in the blood samples from 61 HCC patients and 38 healthy controls were assessed by flow cytometry (FCM). The mRNA expression levels of IL-17, IL-23p19 and RORc in peripheral blood mononuclear cells (PBMC) were detected by quantitative real-time PCR. The potential correlation of increased Th17 cells in blood with the clinical characteristics of the 61 patients, including gender, age, preoperative AFP concentration, tumor diameter, portal vein tumor thrombus (PVTT), metastasis and TNM stages was analyzed. Statistical analysis was performed using the software GraphPad Prizm 5.0. RESULTS: The number of Th17 cells in 61 HCC patients was significantly higher than that in the normal controls (4.67% ± 0.79% vs 3.25% ± 0.68%, P < 0.0001). The same tendency was also found in the mRNA levels of IL-17, IL-23p19 and RORc in PBMC (P < 0.05). The increased level of Th17 cells in HCC patients showed a positive correlation with the tumor size, PVTT, metastasis and TNM stages (P < 0.05 for each group). The level of Th17 cells in HCC patients was increased along with the increasing TNM stages I to stage IV: 4.05% ± 0.82%, 4.32% ± 0.67%, 4.94% ± 0.70%, and 5.22% ± 0.87%, respectively, where the level of Th17 cells in patients with advanced stage of HCC (III-IV) was significantly higher than that in early stage (I-II, P = 0.0008). CONCLUSION: The increased of level of Th17 cells in peripheral blood of HCC is significantly correlated with the tumor size, PVTT, metastasis and TNM stage, indicating that the Th17 cells might participate in promoting invasion and progression of HCC directly or indirectly by secreting characteristic cytokines.

[Effects of astilbin on maturation and immunologic function of mouse bone marrow-derived dendritic cells].

OBJECTIVE: To explore the effects of astilbin on the maturation and immunologic function of mouse bone marrow-derived dendritic cells (DCs). METHODS: Mouse bone marrow cells were cultured with recombinant mouse granulocyte-macrophage colony-stimulating factor and interleukin-4 (IL-4) for 5 days to get immature DCs (imDCs), then the imDCs was cultured in the presence of 1 microg/mL lipopolysaccharide (LPS) or LPS (1 microg/mL) plus astilbin (25, 50, 100 microg/mL) for 48 h. Then, the cells were harvested, and the apoptosis, immunophenotypes and antigen phagocytosis capability of imDCs in LPS, and low-, medium- and high-dose astilbin groups were analyzed by flow cytometry. Contents of p40 subunit of interleukin-12 (IL-12p40) in the supernatants were detected with enzyme-linked immunosorbent assay (ELISA). The stimulatory activity of the harvested cells on allogeneic T cells in mixed lymphocyte reactions (MLR) was tested by incorporation of 3H-thymidine, and the contents of IL-2, IL-4, IL-10 and interferon-gamma (INF-gamma) in the supernatants of MLR were examined by ELISA. RESULTS: At the concentrations of 25 to 100 microg/mL, astilbin exhibited no toxicity on co-cultured DCs. Compared with the lipopolysaccharide, low-, medium- and high-dose astilbin could decrease the expression levels of major histocompatibility complex-Ia (MHC-Ia), CD40, CD80 and CD86 molecules in DCs. DCs in the low-, medium- and high-dose astilbin groups exhibited weaker capabilities for antigen phagocytosis and less contents of IL-12p40 in the supernatants than in the LPS group. Furthermore, low-, medium- and high-dose astilbin showed weak activities in stimulating the proliferation of allogeneic T cells as compared with the LPS (P<0.05). Compared with the LPS, low-, medium- and high-dose astilbin could decrease IL-2 and INF-mu secretion from T cells in MLR but had no effect on IL-10 secretion. CONCLUSION: Astilbin can inhibit maturation of mouse bone marrow-derived DCs with dose-dependent effect and exert negative effects on immunologic function of the DCs.

Simple Self-Assembled Targeting DNA Nano Sea Urchin as a Multivalent Drug Carrier.

An ideal drug delivery platform with high cell selectivity, drug payload capacity, and cellular internalization capability is usually of the essence for targeted cancer chemotherapy. Herein, by combining palindromic DNA strands with a targeting aptamer probe, we demonstrated a self-assembled nanoscale sea urchin-shaped structure (called aptamer-NSU) as a multivalent carrier capable of executing targeted cancer cell imaging and drug delivery. The DNA nanostructure is composed of a spherical trunk and surface-confined spines: the former is assembled from only one biotinylated DNA containing four different palindrome domains, and the latter is a biotinylated aptamer (Sgc8) conjugated to the trunk surface via streptavidin-biotin affinity interaction. The spherical trunk can densely load doxorubicin (Dox), and the surface-confined Sgc8 probes can function as targeting moieties to specifically bind to target cells in a polyvalent-binding fashion. Atomic force microscopy (AFM) and gel electrophoresis show the assembly of Sgc8-NSU. The confocal fluorescence imaging demonstrates that fluorescently labeled Sgc8-NSU can specifically image CEM cells. Flow cytometric analyses indicate that Sgc8-NSU exhibits the multivalent binding effect, achieving the significant improvement in binding affinity and selectivity compared with free Sgc8. Moreover, the CCK-8 assay confirmed that Dox-loaded Sgc8-NSU induces an enhanced cellular cytotoxicity to target cancer cells but not to negative nontarget cells. The developed DNA nanoplatform is expected to provide a valuable insight into constructing structural DNA nanotechnology-based drug delivery nanovehicles suitable for targeted cancer therapy.

[Protective effects of astilbin on renal ischemia-reperfusion injury in rats].

OBJECTIVE: To investigate the protective effects of astilbin on renal ischemia-reperfusion (IR) injury in rats. METHODS: Twenty-four male SD rats, two months old, were randomly allocated into three groups: sham-operated group (n=8), untreated group (n=8) and astilbin group (n=8). Rats in the untreated group and the astilbin group underwent temporary renal artery occlusion to induce IR injury. The rats in the astilbin group were intraperitoneally injected with 12 mg/mL astilbin at a dose of 30 mg/kg from 3 day before IR injury until to be sacrificed once per day, and rats in the untreated group were injected with equal volume of normal saline at the same time. After 6-hour reperfusion, blood urea nitrogen (BUN) and serum creatinine (SCr) and histological changes of the renal tissues were detected to evaluate renal injury. Expressions of monocyte chemoattractant protein-1 (MCP-1) mRNA and protein in the renal tissues and the serum contents of interleukin-6 (IL-6) and IL-1beta were also measured with semi-quantitative reverse transcription-polymerase chain reaction, Western blotting or enzyme-linked immunosorbent assay. RESULTS: Compared with the untreated group, BUN and SCr levels were significantly decreased in the astilbin group after 6-hour reperfusion (P<0.01), and similar results were also found in histological examination. The expressions of MCP-1 mRNA and protein in renal tissues in the astilbin group were lower than those in the untreated group. The serum contents of IL-6 and IL-1beta were decreased in the astilbin group as compared with the untreated group (P<0.01). CONCLUSION: Astilbin can ameliorate kidney IR injury in rats by inhibiting the production of chemokine MCP-1 and cytokines IL-6 and IL-1beta.

DNA nanostructures from palindromic rolling circle amplification for the fluorescent detection of cancer-related microRNAs.

Herein, DNA nanostructures were prepared via a palindromic padlock probe-based rolling circle amplification (called P-RCA) and then employed to implement the sensitive and specific detection of let-7a miRNA extracted from cancer cells without chemical modification. The presence of target let-7a miRNA as a polymerization primer can trigger the P-RCA process, generating a long tandemly repetitive DNA strand. The resulting products can fold into nanostructures via self-hybridization of palindromic regions and possess numerous double-stranded fragments. In this case, the strong fluorescent signal is detected upon exposure to SYBR Green I. As a result, in homogeneous solution, target miRNA can be detected down to 6.4 pM with a wide dynamic range. A high specificity was demonstrated by the excellent discrimination between let-7 miRNA family members, while the applicability of this sensing system in complex biological environments was confirmed by the analysis of target miRNAs extracted from HeLa cells. It should be noted that increasing numbers of palindromic fragments in padlock probe further increases signal amplification efficiency. The experimental results indicate that the newly proposed P-RCA DNA nanostructures have potential to become a promising analytical platform in biomedical research and clinical diagnosis for the miRNA detection with high sensitivity and good specificity.

Autonomous assembly of ordered metastable DNA nanoarchitecture and in situ visualizing of intracellular microRNAs.

Facile assembly of intelligent DNA nanoobjects with the ability to exert in situ visualization of intracellular microRNAs (miRNAs) has long been concerned in the fields of DNA nanotechnology and basic medical study. Here, we present a driving primer (DP)-triggered polymerization-mediated metastable assembly (PMA) strategy to prepare a well-ordered metastable DNA nanoarchitecture composed of only two hairpin probes (HAPs), which has never been explored by assembly methods. Its structural features and functions are characterized by atomic force microscope (AFM) and gel electrophoresis. Even if with a metastable molecular structure, this nanoarchitecture is relatively stable at physiological temperature. The assembly strategy can be expanded to execute microRNA-21 (miRNA-21) in situ imaging inside cancer cells by labelling one of the HAPs with fluorophore and quencher. Compared with the conventional fluorescence probe-based in situ hybridization (FISH) technique, confocal images revealed that the proposed DNA nanoassembly can not only achieve greatly enhanced imaging effect within cancer cells, but also reflect the miRNA-21 expression level sensitively. We believe that the easily constructed DNA nanoarchitecture and in situ profiling strategy are significant progresses in DNA assembly and molecule imaging in cells.

Increasingly branched rolling circle amplification for the cancer gene detection.

An increasingly branched rolling circle amplification (IB-RCA) which contains a padlock probe (PP) and a structurally tailored molecular beacon (MB) was innovatively developed for highly sensitive detection of cancer gene, Kras gene codon 12. In this system, the PP can be circularized after hybridization with the precisely-matched target DNA, while the stem of MB can be also opened by target DNA, resulting in hybridization with the circularized PP to generate a long tandem single-stranded DNA (ssDNA) product. Since the MB is also designed to hybridize with ssDNA product, the newly-opened MBs are able to trigger the next RCA reactions, therapy producing branched rolling circle amplification (RCA) products and in turn leading to the increasingly branched RCA (IB-RCA). This alternately and continuously operates hybridization-based MB opening and opened MBs-triggered RCA. As a result, a great number of MBs are opened that is associated with a dramatically amplified fluorescent signal, enabling to quantify target DNA down to 100 fM. This sensing method demonstrates a new concept of IB-RCA amplification even in a simple way to efficiently transduce the fluorescence signal, accomplishing the highly sensitive and selective detection of cancer gene.