[Retracted] MicroRNA­365b­3p represses the proliferation and promotes the apoptosis of non­small cell lung cancer cells by targeting PPP5C.

[This retracts the article DOI: 10.3892/ol.2021.12650.].

Structural optimization and in vivo evaluation of a colorectal stent with anti-migration and anti-tumor properties.

Clinically, colorectal stents can only palliatively relieve obstruction caused by colorectal cancer (CRC), with a high incidence of stent migration and tumor-related re-obstruction. To overcome these shortcomings, we developed a colorectal stent composed of a structure-optimized nitinol braided stent and a tubular film including an inner layer of poly (ethylene-co-vinyl acetate) (EVA) and a segmental outer layer of EVA with paclitaxel (PTX). The braiding pattern, segment number, and end shape of the stent were optimized based on the mechanical properties, ex vivo and in vivo anti-migration performance, and tissue response of the stent. The optimized nitinol stent had a structure of one middle segment in a hook-pattern and two end segments in a cross-pattern with two studs on each end in a staggered arrangement. Structure-optimized colorectal stents were prepared and evaluated in vivo. PTX released from the stent was mostly distributed in the rabbit rectum in contact with it. The biosafety of the colorectal stent was evaluated using blood tests, biochemical analysis, anatomical observation, and pathological analysis. The anti-tumor effect of the stent was also evaluated by endoscopy, anatomical observation, and pathological and immunohistochemical analyses in rabbits with orthotopic CRC. The results demonstrate that the optimized colorectal stents have effective anti-migration ability and anti-tumor effects with good biosafety. STATEMENT OF SIGNIFICANCE: In order to overcome the most common disadvantages of migration and re-obstruction of colorectal stents clinically, a colorectal stent composed of a structure-optimized nitinol stent and a tubular film including an inner layer of EVA and a segmental outer layer of EVA with PTX was put forward in this study. The optimized nitinol stent had a structure of one middle segment in hook-pattern and two end segments in cross-pattern with two studs on each end in staggered arrangement. The resulting colorectal stent has been proved with good anti-migration ability, anti-tumor effects, and biosafety in vivo, which provides a safe and effective potential treatment modality for patients with colorectal cancer.

Liver tumor segmentation and classification using FLAS-UNet++ and an improved DenseNet.

BACKGROUND: The incidence of liver tumors is among the top three in China. The treatments of benign and malignant tumors are different. Accurate diagnosis plays an important role in guiding the treatment of tumors. OBJECTIVE: The aim of this study is to solve the following: (1) blurred boundary between the liver tumor and other organs causes incorrect segmentation of liver tumor boundaries; (2) large difference in tumor size and the diversity in texture and grayscale are major challenges in liver tumor classification tasks. METHODS: Firstly, the liver tumor is segmented from the original CT images by a tumor segmentation network, UNet++ with fusion loss and atrous spatial pyramid pooling (FLAS-UNet++). The proposed segmentation method can solve the problem of tumor edge segmentation error by learning the tumor edge information. Secondly they are adaptively cropped according to the tumor volume to reduce the over-fitting and over-sensitivity of the deep network. Thirdly an improved Dense Block is designed to pay more attention to the changes in grayscale and texture between benign and malignant tumors. Finally, the features extracted from the network combined with tumor volume, patient's sex and age, are sent to a classifier for diagnosis. RESULT: Liver tumor segmentation results show that the dice, HD95 reached 71.9%, 12.1 mm, respectively. The classification results show that the accuracy, specificity, sensitivity and area under curve reached 82.4%, 79.8%, 84.4%, 87.5%, respectively. The segmentation and classification results are both better than other's methods and mainstream networks. CONCLUSIONS: In order to solve existing problems of liver tumor CT image classification methods, our method realizes the accurate segmentation and classification of liver tumors in CT images and has important clinical application value.

[Texture filtering based unsupervised registration methods and its application in liver computed tomography images].

Image registration is of great clinical importance in computer aided diagnosis and surgical planning of liver diseases. Deep learning-based registration methods endow liver computed tomography (CT) image registration with characteristics of real-time and high accuracy. However, existing methods in registering images with large displacement and deformation are faced with the challenge of the texture information variation of the registered image, resulting in subsequent erroneous image processing and clinical diagnosis. To this end, a novel unsupervised registration method based on the texture filtering is proposed in this paper to realize liver CT image registration. Firstly, the texture filtering algorithm based on L0 gradient minimization eliminates the texture information of liver surface in CT images, so that the registration process can only refer to the spatial structure information of two images for registration, thus solving the problem of texture variation. Then, we adopt the cascaded network to register images with large displacement and large deformation, and progressively align the fixed image with the moving one in the spatial structure. In addition, a new registration metric, the histogram correlation coefficient, is proposed to measure the degree of texture variation after registration. Experimental results show that our proposed method achieves high registration accuracy, effectively solves the problem of texture variation in the cascaded network, and improves the registration performance in terms of spatial structure correspondence and anti-folding capability. Therefore, our method helps to improve the performance of medical image registration, and make the registration safely and reliably applied in the computer-aided diagnosis and surgical planning of liver diseases.

MicroRNA-365b-3p represses the proliferation and promotes the apoptosis of non-small cell lung cancer cells by targeting PPP5C.

MicroRNA (miR)-365b-3p has been recently reported to induce cell cycle arrest and apoptosis in retinoblastoma; however, its expression pattern and biological function in non-small cell lung cancer (NSCLC) remain unknown. The present study aimed to investigate the functional role of miR-365b-3p in NSCLC. The results demonstrated that miR-365b-3p expression level was significantly decreased in NSCLC tissues and cell lines compared with controls using reverse transcriptase quantitative PCR. Furthermore, miR-365b-3p expression level was overexpressed by miR-365b-3p mimics transfection in A549 cells, whereas it was downregulated following H1299 cell transfection with miR-365b-3p inhibitor. Restoration of miR-365b-3p inhibited cell proliferation, induced cell cycle G0/G1 arrest and stimulated apoptosis in A549 cells using CCK-8 assay, colony formation and flow cytometry assay. However, miR-365b-3p inhibitor had the opposite effects in H1299 cells. Furthermore, results from bioinformatics analysis and luciferase reporter assay confirmed that serine/threonine protein phosphatase 5 (PPP5C) was a direct target of miR-365b-3p. In addition, online Kaplan-Meier plotter software demonstrated that high PPP5C expression level was associated with lower overall survival and disease-free survival in patients with NSCLC. Furthermore, PPP5C knockdown imitated the effects of miR-365b-3p mimics on A549 cell proliferation, cell cycle distribution and apoptosis, whereas its overexpression rescued the effects of miR-365b-3p mimics on A549 cell proliferation, cell cycle distribution and apoptosis. In conclusion, the findings from the present study suggested that miR-365b-3p may partly suppress NSCLC cell behaviors by targeting PPP5C, which may represent a promising therapeutic target for patients with NSCLC.

A cascade-network framework for integrated registration of liver DCE-MR images.

Registration of hepatic dynamic contrast-enhanced magnetic resonance images (DCE-MRIs) is an important task for evaluation of transarterial chemoembolization (TACE) or radiofrequency ablation by quantifying enhancing viable residue tumor against necrosis. However, intensity changes due to contrast agents combined with spatial deformations render technical challenges for accurate registration of DCE-MRI, and traditional deformable registration methods using mutual information are often computationally intensive in order to tolerate such intensity enhancement and shape deformation variability. To address this problem, we propose a cascade network framework composed of a de-enhancement network (DE-Net) and a registration network (Reg-Net) to first remove contrast enhancement effects and then register the liver images in different phases. In experiments, we used DCE-MRI series of 97 patients from Renji Hospital of Shanghai Jiaotong University and registered the arterial phase and the portal venous phase images onto the pre-contrast phases. The performance of the cascade network framework was compared with that of the traditional registration method SyN in the ANTs toolkit and Reg-Net without DE-Net. The results showed that the proposed method achieved comparable registration performance with SyN but significantly improved the efficiency.

Effectiveness of Infliximab on Deep Radiological Remission in Chinese Patients with Perianal Fistulizing Crohn's Disease.

BACKGROUND AND AIMS: Information concerning deep radiological healing of perianal fistulas in Chinese patients with CD is limited. The present study aimed to establish the effectiveness of infliximab on CD-related perianal fistulas using magnetic resonance imaging (MRI) and identify predictors of deep radiological remission of fistulas. METHODS: We retrospectively reviewed patients with CD with draining perianal fistulas treated with infliximab and included only those who underwent clinical assessment and MRI before and after infliximab therapy. RESULTS: Among 178 patients who underwent repeated MRI and clinical assessment, 65.2% had complex fistulas. Post-infliximab therapy, 55.1% of patients with perianal fistulizing CD showed clinical remission and 26.4% presented a clinical response; 38.2% had deep radiological remission, and 34.3% had a partial response based on the Ng score; the Van Assche scores decreased obviously compared with baseline. Prolonged infliximab infusion (18 times) presented higher radiological remission rates in patients with CD with complex fistulas. Concomitant treatment with azathioprine increased the fistula healing rate compared with infliximab alone (50% vs. 36.9%, P < 0.001). Younger age at diagnosis of CD, proctitis and requiring perianal surgery were identified as predictors of poor deep radiological remission of fistulas. Eight of ten patients who stopped infliximab and switched to an alternative agent retained a status of fistula healing in the first year of follow-up. CONCLUSIONS: Infliximab induced deep radiological remission of perianal fistulas in Chinese patients with CD. Routine MRI should be used to monitor fistula healing. Patients with younger age at diagnosis of CD, proctitis, and/or requiring perianal surgery should receive combined therapy and careful monitoring.

Efficacy of early intervention on the bowel damage and intestinal surgery of Crohn's disease, based on the Lémann index.

BACKGROUND: Clinicians aim to prevent progression of Crohn's disease (CD); however, many patients require surgical resection because of cumulative bowel damage. The aim of this study was to evaluate the impact of early intervention on bowel damage in patients with CD using the Lémann Index and to identify bowel resection predictors. METHODS: We analyzed consecutive patients with CD retrospectively. The Lémann Index was determined at the point of inclusion and at follow-up termination. The Paris definition was used to subdivide patients into early and late CD groups. RESULTS: We included 154 patients, comprising 70 with early CD and 84 with late CD. After follow-up for 17.0 months, more patients experienced a decrease in the Lémann Index (61.4% vs. 42.9%), and fewer patients showed an increase in the Lémann Index (20% vs. 35.7%) in the early compared with the late CD group. Infliximab and other therapies reversed bowel damage to a greater extent in early CD patients than in late CD patients. Twenty-two patients underwent intestinal surgery, involving 5 patients in the early CD group and 17 patients in the late CD group. Three independent predictors of bowel resection were identified: baseline Lémann index ≥ 8.99, disease behavior B1, and history of intestinal surgery. CONCLUSIONS: Early intervention within 18 months after CD diagnosis could reverse bowel damage and decrease short-term intestinal resection. Patients with CD with a history of intestinal surgery, and/or a Lémann index > 8.99 should be treated aggressively and monitored carefully to prevent progressive bowel damage.

Fracture Characteristics and Analysis in Dissimilar Cu-Al Alloy Joints Formed via Electromagnetic Pulse Welding.

The aim of this study was to identify and analyze the fatigue fracture characteristics of dissimilar Al 6061 to Cu (UNS C11000) lap joints made with ultrafast electromagnetic pulse welding (EMPW) via fractography, stress analysis and finite element simulation. It was observed that EMPW generated an annular (or ring-shaped) bonding area, with weld zones and a central non-weld zone when viewed from the cross section. Two types of failure modes occurred in relation to the cyclic loading levels: base metal fracture or transverse through-thickness (TTT) crack growth at a higher loading level, and joint interfacial failure at a lower loading level. In the interfacial failure, fatigue crack initiated from the outer edge of annular welding area, and propagated to form an approximate elliptical boundary. Fatigue crack propagation was characterized by fatigue striations existing in discrete areas on the fracture surface. This was attributed to a coupled role of shear and normal stresses present in a tensile lap shear sample due to the bending moment caused by the inherent misalignment. The final rapid fracture started from elliptical boundary with elongated shear dimples. Both theoretical stress analysis and finite element model revealed the maximum stress and stress concentration along the outer edge, where fatigue crack initiation occurred.

Angiotensin-converting enzyme 2 regulates autophagy in acute lung injury through AMPK/mTOR signaling.

Autophagy exerts a dual role in promoting cell death or survival. Recent studies have shown that it may play an important role in lipopolysaccharide (LPS)-induced acute lung injury (ALI). It was also suggested that angiotensin converting enzyme 2 (ACE2) may participate in the regulation of autophagy. The present study aims to investigate the role of autophagy in ALI and the involvement of ACE2. The regulation of the APMK/mTOR pathway was explored to clarify the underlying mechanism. The results showed that autophagy played an important role in ALI induced by LPS, as the autophagy inhibitor 3-methyladenine (3-MA) mitigated the severity of ALI. ACE2 activator resorcinolnaphthalein and inhibitor MLN-4760 significantly affected the histological appearance and wet/dry (W/D) ratio of the lung and altered the ACE2 activity of the lung, tumor necrosis factor-α (TNF-α) and interleukin-1ß (IL-1ß) levels in bronchoalveolar lavage fluid (BALF) and myeloperoxidase (MPO) levels in lung tissue. Furthermore, LPS, resorcinolnaphthalein and MLN-4760 significantly affected the expression of autophagy proteins Beclin-1, LC3-I and LC3-II. To explore the mechanism of ACE2 on lung autophagy, we measured the phosphorylation of AMPK/mTOR after mice were treated with LPS and resorcinolnaphthalein or MLN-4760. The results revealed that resorcinolnaphthalein and MLN-4760 both significantly altered the phosphorylation of AMPK/mTOR. Finally, we found that AMPK inhibitor (8-bAMP) and mTOR activator (propranolol) both abolished the effects of ACE2 activator (resorcinolnaphthalein) on the expression of lung autophagy proteins Beclin-1, LC3-I and LC3-II. In conclusion, these findings suggest that ACE2 could alleviate the severity of ALI, inflammation and autophagy in lung tissue through the AMPK/mTOR pathway.

A Novel Magnetic Contrast Agent for Gastrointestinal Mucosa-Targeted Imaging Through Oral Administration.

The development of functional contrast agents for diagnosis and therapy of functional gastrointestinal disorders has been a focus of research in recent years. Owing to the excellent distribution and function of 5-HT3 in gastrointestinal mucosa, a novel magnetic contrast agent (AH-CTS-Gd nanosphere) was prepared based on chitosan and 5-HT3 receptors, which realize multifunctional assessment of gastric emptying and gastrointestinal mucosa-targeted MR imaging. The obtained AH-CTS-Gd nanosphere was administered orally to avoid potential toxicity from intravenous administration of a high dose. The results showed that a suitable gastric emptying time and clear gastrointestinal mucosa structure can be observed using the obtained AH-CTS-Gd nanosphere. Immunofluorescence and TEM images of gastrointestinal mucosa suggested a strong combination of the AH-CTS-Gd nanosphere with gastrointestinal mucosa because chitosan and Anti-5-HT3R can combine with gastrointestinal mucosa through electrostatic adherence and antigen-antibody binding. This technology has potential applications in the examination of functional gastrointestinal diseases, without affecting the detection of gastric emptying, possibly enhancing mucosal imaging.

Evaluating the effectiveness of infliximab on perianal fistulizing Crohn's disease by magnetic resonance imaging.

BACKGROUND AND AIM: Data on the radiologic evaluation of perianal fistulizing Crohn's disease (PFCD) naïve to anti-tumor necrosis factor therapy are scarce, especially in Asian populations. We assessed the effectiveness of infliximab (IFX) on PFCD and explored predictors of 'deep remission' based on clinical and radiologic assessments. METHODS: Patients with Crohn's disease and active anal fistulas attending our care center for IFX therapy were prospectively enrolled. Each patient underwent clinical examination according to the Fistula Drainage Assessment Index, endoscopy for assessment of Crohn's Disease Activity Index (CDAI) and Perianal Crohn's Disease Activity Index (PCDAI), magnetic resonance imaging (MRI) to determine Van Assche score and Ng score, and laboratory tests up to 2 weeks prior to the start of and up to 2 weeks after the sixth IFX therapy (Week 32). RESULTS: Among 38 patients treated with IFX, 52.6% achieved clinical remission based on the Fistula Drainage Assessment Index and 42.1% achieved deep remission based on Ng score. Van Assche score (from 14.5 ± 4.26 to 7.36 ± 7.53), CDAI (from 170 ± 92 to 71 ± 69) and PCDAI (from 7.45 ± 2.65 to 2.44 ± 3.20) decreased significantly after six IFX treatments. The only predictor of deep remission was simple fistula (P = 0.004, odds ratio = 3.802, 95% confidence interval: 1.541-9.383). CONCLUSIONS: IFX has been shown to have appreciable effectiveness in Chinese patients with PFCD. MRI is the gold standard for evaluating PFCD, but Van Assche score has some limitations.

Dynamic Melting Properties of Photoswitch-Modified DNA: Shearing versus Unzipping.

We use dynamic force spectroscopy to study the melting properties of azobenzene-modified double-stranded DNA (azo-dsDNA) in both the shearing and unzipping geometries. By fitting the rupture force vs loading rate data with a Friddle-Noy-De Yoreo model, we extract the location of the barrier (xt), the equilibrium force for the bond/transducer system (Feq), and the dissociation rate of dsDNA (koff0). We find that the koff0 of azo-dsDNA increases after UV illumination (365 nm) in both the shearing and unzipping geometries. Notably, we find that koff0 of azo-dsDNA in the unzipping geometry is 5-7 orders of magnitude larger than that in the shearing geometry, a result that helps explain the dependence of koff0 on the azobenzene photoswitch position during shearing experiments. We also extract the difference of free energy (ΔGbu) between binding and unbinding states of azo-dsDNA with Feq and the system spring constant (kc). Our results provide important insights into the dynamic melting properties of azo-dsDNA and a new route for designing applications for reconfigurable sensors, stimulus-response materials, and nanoscale energy harvesting schemes based on photoswitch-modified biomolecules such as DNA.

Local Density Fluctuations Predict Photoisomerization Quantum Yield of Azobenzene-Modified DNA.

Azobenzene incorporated into DNA has a photoisomerization quantum yield that depends on the DNA sequence near the azobenzene attachment site. We use Molecular Dynamics computer simulations to elucidate which physical properties of the modified DNA determine the quantum yield. We show for a wide range of DNA sequences that the photoisomerization quantum yield is strongly correlated with the variance of the number of atoms in close proximity to the outer phenyl ring of the azobenzene group. We infer that quantum yield is controlled by the availability of fluctuations that enable the conformational change. We demonstrate that these simulations can be used as a qualitative predictive tool by calculating the quantum yield for several novel DNA sequences, and confirming these predictions using UV-vis spectroscopy. Our results will be useful for the development of a wide range of applications of photoresponsive DNA nanotechnology.

Combination therapy with human umbilical cord mesenchymal stem cells and angiotensin-converting enzyme 2 is superior for the treatment of acute lung ischemia-reperfusion injury in rats.

Acute lung ischemia-reperfusion injury (ALIRI) is a serious disease that seriously affects human's life. In this study, we aimed to explore a more effective treatment method by combining human umbilical cord mesenchymal stem cells (HUMSCs) and angiotensin-converting enzyme 2 (ACE2) for ALIRI. Fifty rats were firstly divided into five groups, namely sham surgery group (sham) and four model groups (model, ACE2, HUMSCs and HUMSCs + ACE2) that were reperfused with 0.1 ml physiological saline (PS), 0.1 ml PS containing 1 × 10(6) lentiviral-ACE2/HUMSCs/ACE2 + UMSCs, respectively. Quantitative reverse transcription-PCR (qRT-PCR) and western blot assays were then conducted to detect the messenger RNA (mRNA) and protein levels of inflammatory cytokines [intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), tumour necrosis factor α (TNF-α), nuclear factor κB (NF-κB), platelet-derived growth factor (PDGF) and angiotensin II (Ang II)], antioxidant proteins [NAD(P)H quinone oxidoreductase 1 (NQO1), heme oxygenase 1 (HO-1)], DNA damage and apoptotic indicators [BCL2-associated X (Bax), cleaved caspase-3 (C-Csp 3), cleaved-poly(ADP-ribose) polymerase (C-PARP), Y-H2AX], anti-apoptotic indicator (Bcl-2) and smooth muscle cell proliferation indicator [connexin 43 (Cx43)]. According to the qRT-PCR and western results, the mRNA and protein expression levels of ICAM-1, VCAM-1, TNF-α, NF-κB, PDGF, Bax, C-Csp 3, C-PARP and Y-H2AX were significantly higher in model group than those in sham group and they were significantly reduced by HUMSCs or ACE2 treatment (P < 0.05). On the contrary, Bcl-2 showed an opposite expression trend with the previous proteins. The mRNA and protein levels of NQO1 and HO-1 were sequentially increased in sham, model, ACE2, HUMSCs and HUMSCs + ACE2 groups. Besides, HUMSCs combined with ACE2 exhibited a better inhibition effect on ALIRI than HUMSCs or ACE2 alone (P < 0.05). In summary, HUMSCs combined with ACE2 was demonstrated to have the best therapeutic effect on ALIRI through anti-inflammation, oxidative stress and anti-apoptotic processes.

Optimal b value of diffusion-weighted imaging on a 3.0T magnetic resonance scanner in Crohn's disease.

AIM: To determine the optimal b value of diffusion-weighted imaging for detecting active inflammation in Crohn's disease. METHODS: Thirty-one patients clinically diagnosed with active Crohn's disease were referred for magnetic resonance examination. All patients were scanned on a 3.0T magnetic resonance scanner using the same protocol involving four different b values (800, 1500, 2000 and 2500 s/mm(2)). The diagnostic effect of diffusion-weighted imaging was evaluated and compared with endoscopic findings. The diffusion-weighted image quality of four b value groups was evaluated and apparent diffusion coefficient was measured for both normal and inflammatory intestinal segments. RESULTS: The contrast-to-noise ratio and signal-to-noise ratio were not satisfied when b value 2000 or 2500 s/mm(2) was adopted (36.52 ± 14.95 vs 34.78 ± 24.83, P > 0.05; 53.58 ± 23.45 vs 47.58 ± 29.67, P > 0.05). The qualitative image quality was not enough to meet diagnostic requirement. No matter which b value was chosen, the apparent diffusion coefficient of inflammatory intestinal segments was significantly lower than that of normal intestinal segments (1.38 ± 0.28 vs 2.00 ± 0.38, P < 0.01; 1.09 ± 0.20 vs 1.50 ± 0.28, P < 0.01; 0.95 ± 0.19 vs 1.34 ± 0.28, P < 0.01; 0.88 ± 0.14 vs 1.20 ± 0.21, P < 0.01). The lesion detection rate (90.32%), diagnostic sensitivity (81.18%) and specificity (95.10%) would be appropriate when b value 1500 s/mm(2) was adopted. CONCLUSION: High b value is suitable for intestinal DW examination on a high field MR scanner.

Dynamic force spectroscopy of photoswitch-modified DNA.

We apply a combination of photoswitch-modified DNA and AFM-based pulling measurements to study the force-induced melting of double-stranded DNA in the unzipping geometry. We measure the differences in peak rupture force for azobenzene-modified DNA, as the incorporated azobenzenes are photoswitched reversibly between the trans and the cis form. Fitting our rupture force versus loading rate data, we obtain off rate (koff) at zero force values in the range of ∼10 s(-1). We show that the change in peak rupture force and koff induced by destabilizing the DNA duplex depends on the position of the destabilizing azobenzene photoswitch relative to the force-loading site. When the azobenzenes are proximal to the unzipping end, the decrease in peak force and koff upon azobenzene photoisomerization is significantly larger than when the azobenzene is distal to the site of force loading. We interpret these results as experimental evidence supporting the picture that the destabilization of a double-stranded DNA by a photoswitch isomerization is localized to a small bubble around the photoswitch.

Photoisomerization quantum yield of azobenzene-modified DNA depends on local sequence.

Photoswitch-modified DNA is being studied for applications including light-harvesting molecular motors, photocontrolled drug delivery, gene regulation, and optically mediated assembly of plasmonic metal nanoparticles in DNA-hybridization assays. We study the sequence and hybridization dependence of the photoisomerization quantum yield of azobenzene attached to DNA via the popular d-threoninol linkage. Compared to free azobenzene we find that the quantum yield for photoisomerization from trans to cis form is decreased 3-fold (from 0.094 ± 0.004 to 0.036 ± 0.002) when the azobenzene is incorporated into ssDNA, and is further reduced 15-fold (to 0.0056 ± 0.0008) for azobenzene incorporated into dsDNA. In addition, we find that the quantum yield is sensitive to the local sequence including both specific mismatches and the overall sequence-dependent melting temperature (Tm). These results serve as design rules for efficient photoswitchable DNA sequences tailored for sensing, drug delivery, and energy-harvesting applications, while also providing a foundation for understanding phenomena such as photonically controlled hybridization stringency.

Photoswitchable oligonucleotide-modified gold nanoparticles: controlling hybridization stringency with photon dose.

We describe a new class of stimulus-responsive DNA-functionalized gold nanoparticles that incorporate azobenzene-modified oligonucleotides. Beyond the classic directed assembly and sensing behaviors associated with oligonucleotide-modified nanoparticles, these particles also exhibit reversible photoswitching of their assembly behavior. Exposure to UV light induces a trans-cis isomerization of the azobenzene which destabilizes the DNA duplex, resulting in dissociation of the nanoparticle assemblies. The isomerization is reversible upon exposure to blue light, resulting in rehybridization and reassembly of the DNA-linked nanoparticle clusters. We show that perfectly complementary and partially mismatched strands exhibit clearly distinguishable photoinduced melting properties, and we demonstrate that photon dose can thus be used in place of temperature or ionic strength to control hybridization stringency with the ability to discriminate single-base mismatches.

[The effect of anticoagulant thrombolytic therapy on acute deep venous thrombosis prognosis].

OBJECTIVE: To explore the effect of anticoagulant thrombolytic therapy on acute deep venous thrombosis (DVT) and the incidence and severity of post-thrombotic syndrome (PTS). METHOD: A total of 111 patients (113 limbs) with central or mixed types of deep venous thrombosis admitted from March 2003 to November 2008 were analyzed. The patients were divided into 3 groups by different therapies: anticoagulant group (41 limbs), thrombolysis group (27 limbs), and catheter-directed thrombolysis group (45 limbs). In the follow-up, patients' swelling of lower extremity and recanalization of vein were found out by physical examination and venous ultrasound Duplex through following-up. The Villalta and VCSS marking scales were used in rating the incidence and severity of PTS, discussing treatments for acute phase as well as adjuvant treatment for chronic phase and the correlation between the incidence and severity of PTS. RESULTS: The average time of follow-up were (41 ± 19) months in anticoagulant group, (52 ± 11) months in thrombolysis group, and (26 ± 10) months in catheter-directed thrombolysis group. According to the consequences from Villalta and VCSS rating scales, the incidences of PTS in the three groups were 58.5% (24/41), 55.6% (15/27), and 35.6% (16/45), in which 20.8% (5/24), 3/15, and 1/16 were severe. The the catheter-directed thrombolysis group had a better consequence than the other two groups in reducing incidence and severity of PTS (P < 0.05). The differences of circumferences of lower extremities of all patients had obvious improvement compared to that before the treatments. For patients who were treated by catheter-directed thrombolysis, the thigh circumference difference and calf circumference difference were (0.5 ± 1.0) cm and (0.7 ± 1.0) cm, which were more obvious compared to other two groups (P < 0.05). Most patients had their external-iliac and common-femoral veins recanalized. Using anticoagulant pharmaceuticals and compression stockings can lead to a reduction in the incidence of PTS. CONCLUSIONS: The incidences and symptoms of PTS and swelling of limbs can be significantly moderated by catheter-directed thrombolysis based on anticoagulating in the acute phase of DVT. Consequently, it would be the most efficient way in decreasing the occurrences of PTS and moderating the severities of PTS with the aids of regular anticoagulating and compression stockings.