Bubble Turbulent Gas-Permeable Membrane for Ammonia Recovery from Swine Wastewater: Mass Transfer Enhancement and Antifouling Mechanisms.

Recovering ammonium from swine wastewater employing a gas-permeable membrane (GM) has potential but suffers from the limitations of unattractive mass transfer and poor-tolerance antifouling properties. Turbulence is an effective approach to enhancing the release of volatile ammonia from wastewater while relying on interfacial disturbance to interfere with contaminant adhesion. Herein, we design an innovative gas-permeable membrane coupled with bubble turbulence (BT-GM) that enhances mass transfer while mitigating membrane fouling. Bubbles act as turbulence carriers to accelerate the release and migration of ammonia from the liquid phase, increasing the ammonia concentration gradient at the membrane-liquid interface. In comparison, the ammonium mass transfer rate of the BT-GM process applied to real swine wastewater is 38% higher than that of conventional GM (12 h). Through a computational fluid dynamics simulation, the turbulence kinetic energy of BT-GM system is 3 orders of magnitude higher than that of GM, and the effective mass transfer area is nearly 3 times that of GM. Seven batches of tests confirmed that the BT-GM system exhibits remarkable antifouling ability, broadens its adaptability to complex water quality, and practically promotes the development of sustainable resource recycling.

Ternary Lithium Nickel Boride with 1D Rapid-Ion-Diffusion Channels as an Anode for Use in Lithium-Ion Batteries.

Anode materials with high-rate performances and good electrochemical stabilities are urgently required for the grid-scale application of lithium-ion batteries (LIBs). Theoretically, transition metal borides are desirable candidates because of their appropriate working potentials and good conductivities. However, the reported metal borides exhibit poor performances owing to their lack of favorable Li+ storage sites and poor structural stabilities during long-term charging/discharging. In this work, a ternary alkali metal boride, Li1.2 Ni2.5 B2 , which displays a high Li+ storage capacity and remarkable electrochemical stability and an excellent rate performance is studied. In contrast to conventional transition metal borides, the introduction of Li atoms facilitates the formation of 1D Ni/B-based honeycomb channels during synthesis. This Ni/B framework successfully sustains the strain during Li+ intercalation and deintercalation, and thus, the optimized Li1.2 Ni2.5 B2 anode exhibits an excellent cycle stability over 500 charge/discharge cycles. This electrode also exhibits superior reversible capacities of 350, 183, and 80 mA h g-1 at 0.1, 1, and 5 A g-1 , respectively, indicating the considerable potential of the 1D Ni/B framework as a commercially available fast-charging LIB anode.

The Characteristics of Extracranial Internal Carotid Artery and Their Relationship With Surgical Outcomes in Patients With Moyamoya Disease: A Combined Head-and-Neck Vessel Wall MR Imaging Study.

BACKGROUND: The features of intracranial arteries in patients with Moyamoya disease (MMD) have been widely investigated. However, the MR characteristics of extracranial internal carotid artery (EICA) and their effect on outcomes of revascularization treatment are not fully understood. PURPOSE: To investigate the characteristics of EICA and their relationship with outcomes of revascularization treatment in adult patients with MMD based on higher-resolution MRI (HRMRI). STUDY TYPE: Prospective interventional outcomes. SUBJECTS: Two hundred eighty-eight consecutive patients with MMD (mean age: 43.7 ± 11.2 years; 140 male). FIELD STRENGTH/SEQUENCE: Turbo inversion recovery magnitude T1-weighted imaging and turbo spin echo (TSE) T2-weighted imaging, three-dimensional time-of-flight MR angiography, T2-fluid attenuated inversion recovery, and 3D T1-SPACE vessel wall imaging at 3.0 T. ASSESSMENT: The HRMRI characteristics of EICA were determined. The relationship between the characteristics of EICA (proximal stenosis, diffuse wall thickening, carotid plaques, and luminal thrombosis) and stroke outcomes of revascularization treatment in patients with MMD was analyzed. The discriminative ability of EICA characteristics in combination with intracranial carotid artery features (involvement of vessel segments, bilateral involvement, and Suzuki stage) to determine stroke outcomes was compared with that of intracranial artery features alone during a mean 8.0 months follow-up period. STATISTICAL TESTS: Cox proportional hazards models and Kaplan-Meier curves to calculate the hazard ratios (HRs) for stroke with 95% confidence intervals (CIs). Area under the receiver operating characteristic curve (AUC) for assessing discriminative performance. A P value <0.05 was considered statistically significant. RESULTS: During a mean 8.0 ± 2.2 months follow-up, of the 288 participants, 137 had proximal stenosis (47.6%), 106 had diffuse wall thickening (36.8%), 60 had carotid plaques (20.8%), and 27 had luminal thrombosis (9.4%) of EICA. Of these features, proximal stenosis (HR = 2.86; 95% CI = 1.13-7.29) and diffuse wall thickening (HR = 2.62; 95% CI = 1.16-5.94) of EICA were significantly associated with stroke after surgery, before and after adjusting for confounding factors. In discriminating the stroke outcomes after surgery, combining characteristics of EICA with features of intracranial arteries resulted in a significant incremental improvement (DeLong test, P < 0.05) in the AUC over that obtained with features of intracranial arteries alone (AUC: 0.73 vs. 0.60-0.64). CONCLUSION: Proximal stenosis and diffuse wall thickening of EICA were significantly associated with stroke outcomes after surgery in patients with MMD. Our findings suggest that understanding the characteristics of EICA has added value for intracranial vessels in predicting future events after surgery in patients with MMD. EVIDENCE LEVEL: 2 TECHNICAL EFFICACY: Stage 4.

Long-term outcomes of moyamoya disease versus atherosclerosis-associated moyamoya vasculopathy using high-resolution MR vessel wall imaging.

OBJECTIVES: We aimed to compare the long-term outcomes and surgical benefits between moyamoya disease (MMD) and atherosclerosis-associated moyamoya vasculopathy (AS-MMV) using high-resolution MRI (HRMRI). METHODS: MMV patients were retrospectively included and divided into the MMD and AS-MMV groups according to vessel wall features on HRMRI. Kaplan-Meier survival and Cox regression were performed to compare the incidence of cerebrovascular events and prognosis of encephaloduroarteriosynangiosis (EDAS) treatment between MMD and AS-MMV. RESULTS: Of the 1173 patients (mean age: 42.4±11.0 years; male: 51.0%) included in the study, 881 were classified into the MMD group and 292 into the AS-MMV group. During the average follow-up of 46.0±24.7 months, the incidence of cerebrovascular events in the MMD group was higher compared with that in the AS-MMV group before (13.7% vs 7.2%; HR 1.86; 95% CI 1.17 to 2.96; p=0.008) and after propensity score matching (6.1% vs 7.3%; HR 2.24; 95% CI 1.34 to 3.76; p=0.002). Additionally, patients treated with EDAS had a lower incidence of events than those not treated with EDAS, regardless of whether they were in the MMD (HR 0.65; 95% CI 0.42 to 0.97; p=0.043) or AS-MMV group (HR 0.49; 95% CI 0.51 to 0.98; p=0.048). CONCLUSIONS: Patients with MMD had a higher risk of ischaemic stroke than those with AS-MMV, and patients with both MMD and AS-MMV could benefit from EDAS. Our findings suggest that HRMRI could be used to identify those who are at a higher risk of future cerebrovascular events.

Differential Diagnosis of Benign and Malignant Breast Papillary Neoplasms on MRI With Non-mass Enhancement.

RATIONALE AND OBJECTIVES: To explore the differential diagnosis of benign and malignant papillary neoplasms on MRI with non-mass enhancement. MATERIALS AND METHODS: A total of 48 patients with surgically confirmed papillary neoplasms showing non-mass enhancement were included. Clinical findings, mammography and MRI features were retrospectively analyzed, and lesions were described according to the breast imaging report and data system (BI-RADS). Multivariate analysis of variance was used to compare the clinical and imaging features of benign and malignant lesions. RESULTS: Fifty-three papillary neoplasms were shown on MR images with non-mass enhancement, including 33 intraductal papilloma and 20 papillary carcinomas (9 intraductal papillary carcinoma, 6 solid papillary carcinomas, and 5 invasive papillary carcinoma). Mammography showed amorphous calcification in 20% (6/30), of which 4 were in papilloma and 2 were in papillary carcinoma. On MRI, papilloma mostly showed linear distribution in 54.55% (18/33), clumped enhancement in 36.36% (12/33). Papillary carcinoma showed segmental distribution in 50% (10/20), clustered ring enhancement in 75% (15/20). ANOVA showed age (p = 0.025), clinical symptoms (p < 0.001), apparent diffusion coefficient (ADC) value (p = 0.026), distribution pattern (p = 0.029) and internal enhancement pattern (p < 0.001) were statistically significant between benign and malignant of papillary neoplasms. Multivariate analysis of variance suggested that the internal enhancement pattern was the only statistically significant factor (p = 0.010). CONCLUSIONS: Papillary carcinoma on MRI with non-mass enhancement mostly showed internal clustered ring enhancement, while papilloma mostly showed internal clumped enhancement; additional mammography is of limited diagnostic value, and suspected calcification occurs mostly in papilloma.

Poly(ether imide) Porous Membrane Developed by a Scalable Method for High-Performance Lithium-Sulfur Batteries: Combined Theoretical and Experimental Study.

Lithium-sulfur (Li-S) batteries are one of the emerging candidates for energy storage systems due to their high theoretical energy density and the abundance/nontoxicity/low cost of sulfur. Compared with conventional lithium-ion batteries, multiple new challenges have been brought into this advanced battery system, such as polysulfide shuttling in conventional polyolefin separators and undesired lithium dendrite formation of the Li metal anode. These issues severely affect the cell performance and impede their practical applications. Herein, we develop a poly(ether imide) (PEI)-based membrane with a sponge-like pore morphology as the separator for the Li-S battery by a simplified phase inversion method. This new separator can not only alleviate the new challenges in Li-S batteries but also exhibit excellent ion conductivity, better thermal stability, and higher mechanical strength compared to those of the conventional polypropylene (PP) separator. A combined experimental and theoretical study indicates that the sponge-like morphology of the PEI membrane and its good wettability toward the electrolyte can facilitate uniform ion transportation and suppress dendrite growth. Meanwhile, the PEI molecules exhibit a strong interaction with polysulfides and avoid their shuttling effectively. As a result, the PEI-based Li-S battery shows a much better performance from various aspects (capacity, rate capability, and cycling stability) than that of the PP-based Li-S battery, especially at high charge/discharge current densities and high sulfur loadings. Since the developed PEI membrane can be easily scaled up, this work may accelerate the practical applications of Li-S batteries from the point of separators.

The value of 3D pseudo-continuousarterial spin labeling perfusion imaging in moyamoya disease-Comparison with dynamic susceptibility contrast perfusion imaging.

Background and purpose: 3D pseudo-continuous arterial spin labeling (3D pCASL) is commonly used to measure arterial cerebral blood flow (CBF). The aim of this study was to assess the clinical feasibility and accuracy of 3D pCASL in comparison with dynamic susceptibility contrast (DSC) perfusion imaging in moyamoya disease (MMD). Materials and methods: A total of 174 MMD patients underwent 3D pCASL and DSC-MRI for evaluating cerebral blood perfusion. 3D-pCASL with two single post-labeling delay (PLD) times (1,500 and 2,500 ms) was used to measure CBF. The values of DSC-CBF and ASL-CBF were calculated for major arterial territories including the anterior, middle, and posterior cerebral arteries as well as the areas based on the Alberta Stroke Program Early CT Score (ASPECTS) template. The correlation between DSC-CBF and ASL-CBF was analyzed. The consistency and accuracy between the two methods in assessing the cerebral ischemic state before and after surgery were analyzed. Results: The correlation between ASL (2,500 ms) and DSC-MRI was slightly better than the correlation between ASL (1,500 ms) and DSC-MRI in major vascular territories before revascularization. Significant correlations were observed between ASL (2,500 ms) and DSC-MRI and between ASL (1,500 ms) and DSC-MRI in major vascular territories after revascularization. For 44 surgically treated patients, the scores of ASPECTS for CBF on the operated side were significantly different before and after revascularization (p < 0.05) and showed good consistency on all the examination methods. A comparison of the scores of ASPECTS of the three parameters before and after revascularization showed that there was no statistical difference between them (p > 0.05). Conclusion: Compared to DSC-MRI, 3D pCASL can assess the cerebral blood perfusion in MMD before and after revascularization effectively. 3D pCASL showed the feasibility and clinical utility value in patients with MMD.

DMTHB ameliorates memory impairment in Alzheimer's disease mice through regulation of neuroinflammation.

BACKGROUND: Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases. Growing evidence suggested that AD is associated with neuroinflammation, characterized with the chronic activation of microglial cells and astrocytes along with the subsequent excessive generation of the proinflammatory molecules. This study aimed to investigate the effect and molecular mechanism of Demethylenetetrahydroberberine (DMTHB) on Alzheimer's disease (AD). METHODS: AD mice model were made by intracranial injection of Aß25-35. DMTHB (50 mg/kg or 150 mg/kg) was intragastrically administered every day for three weeks. Morris water maze (MWM) was applied to evaluate the capacity of learning and memory of mice. Pathological change and neuronal death were detected by HE staining Moreover, the expressions of NLRP3, ASC, Caspase 1, IL-6, IL-1ß, TNF-α and Tau in the brain tissue were measured by qRT-PCR and western blot. RESULTS: Our results showed that the cognition of AD mice was significantly improved by DMTHB administration. DMTHB inhibited the activation of the microglia and significantly reduced the expression of Iba-1 in the brains of AD mice. In addition, DMTHB effectively suppressed the activation of NLRP3 inflammasome induced by Aß25-35. The results showed that the content of inflammatory cytokine (TNF-α, IL-1ß and IL-6) in the brains of AD mice were down-regulated by DMTHB treatment. More importantly, DMTHB treatment significantly alleviated hippocampus neuron deformation and apoptosis. CONCLUSION: These results indicated that DMTHB could be a potential medicine against AD through regulation of neuroinflammation.

A self-powered photoelectrochemical cathodic molecular imprinting sensor based on Au@TiO2 nanorods photoanode and Cu2O photocathode for sensitive detection of sarcosine.

Quantitative determination of sarcosine (SAR) in biological liquids is of great importance, as SAR has been recently suggested as a promising biomarker for prostate cancer diagnostics. Herein, a self-powered photoelectrochemical (PEC) molecular imprinted sensor integrated with photoanode (Au@TiO2 nanorods) and photocathode (Cu2O) is proposed for the first time towards the specific and sensitive detection of SAR. With the benefits of strong photocurrent driving force attributed to a large inherent deviation between the Fermi levels of photoanode and photocathode in this system, the photogenerated electrons of Au@TiO2 can rapidly transferred along the outer circuit and attracted by the holes in the valence band of the photocathode, forming a self-powered PEC system and improve the photocurrent of the cathode. Under the optimal conditions, the constructed cathode imprinted sensor has a linear range of 10 nM - 10 µM, and the limitation of detection is 0.19 nM. This work proved that the PEC sensing platform has great potential in the field of miniaturized biosensing without external power supply.

Association of intracranial vessel wall enhancement and cerebral hemorrhage in moyamoya disease: a high-resolution magnetic resonance imaging study.

BACKGROUND AND PURPOSE: This study aimed to investigate the enhancement characteristics of vessel wall in patients with moyamoya disease (MMD) using 3D high-resolution magnetic resonance (MR) imaging and their relationship with initial and recurrent intracranial hemorrhage. METHODS: Consecutive patients with MMD were retrospectively analyzed and classified as intracranial hemorrhagic and non-hemorrhagic groups according to the CT or MR images. The clinical features and vessel wall characteristics were compared between the two groups. Logistic regression was performed to relate the vessel wall characteristics to the initial hemorrhage in MMD patients. Patients in hemorrhagic group were followed up after surgery to evaluate the relationship between vessel wall characteristics and recurrent hemorrhage. RESULTS: A total of 507 MMD patients including 79 hemorrhagic and 428 non-hemorrhagic MMD patients were recruited in the study. We found that hemorrhagic group had more patients with vessel wall enhancements (40.5% vs. 25.7%, p = 0.009) and more eccentric enhanced lesions (17.7% vs. 6.5%, p = 0.001) compared to those in non-hemorrhage group and vessel wall enhancements were independently associated with ipsilateral initial hemorrhage after adjusted for clinical factors (OR = 1.99, CI 1.20-3.28, p = 0.007). Furthermore, three recurrent intracranial hemorrhagic episodes in the present study were all observed in MMD patients with vessel wall enhancement during the long-term follow-up after surgery. CONCLUSIONS: Wall enhancement of intracranial vessels was significantly associated with intracranial hemorrhage in MMD patients. Our findings suggest that vessel wall enhancement may serve as a marker of intracranial hemorrhage.

Low-Tortuosity Water Microchannels Boosting Energy Utilization for High Water Flux Solar Distillation.

Solar distillation through photothermal evaporators has approached solar light energy (E1) limit under no solar concentration but still suffers from modest vapor and clean water production. Herein, a nature-inspired low-tortuosity three-dimensional (3D) evaporator is demonstrated to significantly improve water production. The solar evaporator, prepared from polypyrrole-modified maize straw (PMS), had upright vascular structures enabling high water lifting and horizontal microgaps facilitating broad water distribution to the out-surface. Consequently, this novel PMS evaporator dramatically enhanced the utilization of the solar heat energy stored in the environment (E2) for promoting evaporation. The maximum vapor generation rate of a single PMS respectively increases 2.5 and 6 times compared with the conventional 3D evaporators and the planar evaporators of an identical occupied area. Consequently, a scaled-up PMS array achieved a state-of-the-art vapor generation rate of 3.0 L m-2 h-1 (LMH) under a simulated condition and a record-high clean water production of 2.2 LMH for actual seawater desalination under natural conditions (1 sun intensity). This breakthrough reveals great potentials for cost-effective freshwater production as well as the rational design of high-performance photothermal evaporators for solar distillation.

Effect of BTXA on Inhibiting Hypertrophic Scar Formation in a Rabbit Ear Model.

BACKGROUND: Hypertrophic scar (HS) is a refractory skin disease caused by major physical damage or other inflammation. Some reports found that botulinum toxin type A (BTXA) could be an alternative treatment of the HS. Therefore, the authors studied the effects of BTXA on the treatment of HS and the dose response of BTXA. METHODS: Hypertrophic scars were harvested from the ears of 18 young adult New Zealand big-eared rabbits and treated with BTXA or triamcinolone acetonide (TAC) in vivo experiment. The hypertrophic index (HI) was measured by histological examination. Collagen fibrils were checked by sirius red straining, and the cell nucleuses of fibroblasts were checked by Ki67. RESULTS: The HI of hypertrophic scars with BTXA treatment was lower than that with phosphate-buffered saline treatment (P < 0.05). Compared with the TAC treatment group, the efficacy of treatment with the middle dose of BTXA (1.0, 1.5 IU) had no significant difference, as shown by sirius red staining and immunohistochemistry Ki67. CONCLUSION: These results demonstrated that BTXA effectively improved the appearance of hypertrophic scars and inhibited the formation of collagen fibrils and fibroblasts in vivo. Treatment with the middle dose of BTXA achieved similar efficacy as TAC treatment, indicating that BTXA might be useful for inhibiting hypertrophic scars and worth investigating further. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

De novo design of VEGFR-2 tyrosine kinase inhibitors based on a linked-fragment approach.

Vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase inhibitors have been demonstrated to possess substantial antitumor activity. VEGFR-2 tyrosine kinase inhibitors are crucial for development of antitumor drugs. Based on the crystal structure of VEGFR-2 tyrosine kinase, a linked-fragment strategy was employed to design novel VEGFR-2 tyrosine kinase inhibitors, and 1000 compounds were generated in this process. Absorption, distribution, metabolism, excretion and toxicity (ADMET) were used to screen the 1000 compounds, and 59 compounds were acceptable. Scaffold hopping was then used for further screening, and only four compounds were obtained in this way. Then, the binding energy of the four molecules to VEGFR-2 tyrosine kinase was calculated using molecular docking, and their values were found to be lower than that of Sorafenib. Finally, molecular dynamics simulations were performed on the complex of the compound with the lowest binding energy with VEGFR-2 tyrosine kinase, and the binding model was analyzed. At the end, four chemical entities with novel structures were obtained, and were suggested for experimental testing in future studies.

Ectopic Expression of DREB Transcription Factor, AtDREB1A, Confers Tolerance to Drought in Transgenic Salvia miltiorrhiza.

Drought decreases crop productivity more than any other type of environmental stress. Transcription factors (TFs) play crucial roles in regulating plant abiotic stress responses. The Arabidopsis thaliana gene DREB1A/CBF3, encoding a stress-inducible TF, was introduced into Salvia miltiorrhiza Ectopic expression of AtDREB1A resulted in increased drought tolerance, and transgenic lines had higher relative water content and Chl content, and exhibited an increased photosynthetic rate when subjected to drought stress. AtDREB1A transgenic plants generally displayed lower malondialdehyde (MDA), but higher superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities under drought stress. In particular, plants with ectopic AtDREB1A expression under the control of the stress-induced RD29A promoter exhibited more tolerance to drought compared with p35S::AtDREB1A transgenic plants, without growth inhibition or phenotypic aberrations. Differential gene expression profiling of wild-type and pRD29A::AtDREB1A transgenic plants following drought stress revealed that the expression levels of various genes associated with the stress response, photosynthesis, signaling, carbohydrate metabolism and protein protection were substantially higher in transgenic plants. In addition, the amount of salvianolic acids and tanshinones was significantly elevated in AtDREB1A transgenic S. miltiorrhiza roots, and most of the genes in the related biosynthetic pathways were up-regulated. Together, these results demonstrated that inducing the expression of a TF can effectively regulate multiple genes in the stress response pathways and significantly improve the resistance of plants to abiotic stresses. Our results also suggest that genetic manipulation of a TF can improve production of valuable secondary metabolites by regulating genes in associated pathways.

Promoter analysis of the sweet potato ADP-glucose pyrophosphorylase gene IbAGP1 in Nicotiana tabacum.

KEY MESSAGE: The IbAGP1 gene of sweet potato ( Ipomoea batatas ) encodes the sucrose-inducible small subunit of ADP-glucose pyrophosphorylase. Through expression analysis of 5'-truncations and synthetic forms of the IbAGP1 promoter in transgenic tobacco, we show that SURE-Like elements and W-box elements of the promoter contribute to the sucrose inducibility of this gene. Sweet potato (Ipomoea batatas) contains two genes (IbAGP1 and IbAGP2) encoding the catalytically active small subunits of ADP-glucose pyrophosphorylase, an enzyme with an important role in regulating starch synthesis in higher plants. Previous studies have shown that IbAGP1 is expressed in the storage roots, leaves, and stem tissues of sweet potato, and its transcript is strongly induced by applying sucrose exogenously to detached leaves. To investigate the tissue-specific expression of the IbAGP1 promoter, a series of 5'-truncated promoters extending from bases -1913, -1598, -1298, -1053, -716, and -286 to base +75 were used to drive the expression of the ß-glucuronidase reporter gene (GUS) in tobacco plants (Nicotiana tabacum). Histochemical and fluorometric GUS assays showed that (1) GUS expression driven by the longest fragment (1989 bp) of the IbAGP1 promoter was detected in vegetative tissues (roots, stems, leaves), (2) fragments extending to -1053 or beyond retained strong GUS expression in roots, stems, and leaves, whereas further 5'-deletions resulted in considerable reduction in GUS activity, and (3) the series of 5'-truncated promoters responded differently to exogenously applied sucrose. The 1989-bp IbAGP1 promoter contains five sequences (two AATAAAA, one AATAAAAAA, and two AATAAATAAA) that are similar to sucrose-responsive elements (SURE). These SURE-Like sequences are found at nucleotide positions -1273, -1239, -681, -610, and -189. Moreover, putative W-box elements are found at positions -1985, -1434, -750, and -578. Synthetic promoters containing tandem repeats of the 4X SURE-Like or 4X W-box upstream from a minimal CaMV35S promoter-GUS fusion showed significant expression in transgenic tobacco in response to exogenous sucrose. These results show that SURE-Like elements and W-box elements of the IbAGP1 promoter contribute to the sucrose inducibility of this gene.

Enhancement of RAD51 recombinase activity by the tumor suppressor PALB2.

Homologous recombination mediated by RAD51 recombinase helps eliminate chromosomal lesions, such as DNA double-strand breaks induced by radiation or arising from injured DNA replication forks. The tumor suppressors BRCA2 and PALB2 act together to deliver RAD51 to chromosomal lesions to initiate repair. Here we document a new function of PALB2: to enhance RAD51's ability to form the D loop. We show that PALB2 binds DNA and physically interacts with RAD51. Notably, although PALB2 alone stimulates D-loop formation, it has a cooperative effect with RAD51AP1, an enhancer of RAD51. This stimulation stems from the ability of PALB2 to function with RAD51 and RAD51AP1 to assemble the synaptic complex. Our results demonstrate the multifaceted role of PALB2 in chromosome damage repair. Because PALB2 mutations can cause cancer or Fanconi anemia, our findings shed light on the mechanism of tumor suppression in humans.

Mechanism of the ATP-dependent DNA end-resection machinery from Saccharomyces cerevisiae.

If not properly processed and repaired, DNA double-strand breaks (DSBs) can give rise to deleterious chromosome rearrangements, which could ultimately lead to the tumour phenotype. DSB ends are resected in a 5' to 3' fashion in cells, to yield single-stranded DNA (ssDNA) for the recruitment of factors critical for DNA damage checkpoint activation and repair by homologous recombination. The resection process involves redundant pathways consisting of nucleases, DNA helicases and associated proteins. Being guided by recent genetic studies, we have reconstituted the first eukaryotic ATP-dependent DNA end-resection machinery comprising the Saccharomyces cerevisiae Mre11-Rad50-Xrs2 (MRX) complex, the Sgs1-Top3-Rmi1 complex, Dna2 protein and the heterotrimeric ssDNA-binding protein RPA. Here we show that DNA strand separation during end resection is mediated by the Sgs1 helicase function, in a manner that is enhanced by Top3-Rmi1 and MRX. In congruence with genetic observations, although the Dna2 nuclease activity is critical for resection, the Mre11 nuclease activity is dispensable. By examining the top3 Y356F allele and its encoded protein, we provide evidence that the topoisomerase activity of Top3, although critical for the suppression of crossover recombination, is not needed for resection either in cells or in the reconstituted system. Our results also unveil a multifaceted role of RPA, in the sequestration of ssDNA generated by DNA unwinding, enhancement of 5' strand incision, and protection of the 3' strand. Our reconstituted system should serve as a useful model for delineating the mechanistic intricacy of the DNA break resection process in eukaryotes.

[Visfatin promotes production of monocyte chemotactic protein-1 and interleukin-6 in human endothelial cells via insulin receptor].

OBJECTIVE: Visfatin is a new novel proinflammatory adipocytokine affecting insulin resistance by binding to insulin receptor. To investigate whether visfatin stimulates monocyte chemotactic protein-1 (MCP-1) and interleukin-6 (IL-6) production in human umbilical vein endothelial cells (HUVEC) and mediates insulin receptor (IR) is involved in are not known. METHODS: Cultured HUVEC was treated with different doses and durations of visfatin. Furthermore, HUVEC was pretreated with hydroxy-2-naphthalenylmethylphosphonic acid trisacetoxymethyl ester (HNMPA-(AM)3), a specific inhibitor of IR followed by visfatin (100 ng/ml) treatment. Enzyme-linked immunosorbent assay (ELISA) were used to measure MCP-1 and IL-6 production in HUVEC. Real-time quantitative reverse-transcription polymerase chain reaction (RT-PCR) was used for determining MCP-1 and IL-6 mRNA expression. RESULTS: Visfatin significantly dose- and time- dependently up-regulated protein production of MCP-1 and IL-6 in HUVEC. We therefore found visfatin- induced MCP-1 and IL-6 production and gene expression in HUVEC were inhibited by HNMPA-(AM)3. CONCLUSION: Visfatin induces endothelial MCP-1 and IL-6 production in HUVEC in a dose and time-dependently manner. This action appears to be mediated via insulin receptor pathway.

[Analysis of 216 cases of total laparoscopic hysterectomy].

OBJECTIVE: To investigate the effectiveness and safety of total laparoscopic hysterectomy (TLH). METHODS: A retrospective study of laparoscopic hysterectomy was conducted in this setting. From March 2002 through March 2004, 216 women were subjected to TLH. The average age of the patients was 45.5 years (38-60 years). Out of the 216 patients, 24 had dysfunctional uterine bleeding, 5 atypical endometrial hyperplasia, 139 uterine fibroid, 46 adenomyosis, 2 cervical carcinoma in situ and 36 had a previous lower abdominal surgery. The TLH was carried out using ultrasonic scalpel and the amputated uterus was removed transvaginally. The vagina and peritoneum were closed under laparoscopy. RESULTS: Of the 216 cases who underwent TLH, 23 had bilateral adnexectomy, 36 had ovarian cystectomy, and 54 had adhesiolysis simultaneously. No case was converted to laparotomy. The mean operating time was (103 +/- 35) min. The average amount of blood loss was 83 +/- 45 ml (60-320 ml) during operation. The average hospital stay after operation was (5.3 +/- 1.9) days. There were 4 patients with urinary tract injury in this study population. One bladder perforation was found during operation and repaired under laparoscopy. Two patients had vesicovaginal fistula formation. One ureteral-vaginal fistula was found after operation. The fistula was all closed spontaneously with a prolonged catheter drainage. CONCLUSIONS: TLH appears a safe, effective and reproducible procedure. It is an alternative method for those women who need hysterotomy.

Killing effect of coexpressing cytosine deaminase and thymidine kinase on rat vascular smooth muscle cells.

BACKGROUND: Vascular smooth muscle cell (VSMC) proliferation following arterial injury plays a critical role in a variety of vascular proliferative disorders, such as atherosclerosis and restenosis after balloon angioplasty. Herpes simplex virus-thymidine kinase (HSV-TK)/ganciclovir (GCV) and E. coli cytosine deaminase (CD)/5-fluorocytosine (5-Fc) suicide gene systems have been successfully employed in cardiovascular gene therapy, respectively. We reasoned that coexpression of both HSV-TK with CD suicide genes would lead to increased cell killing. To test this imagine, the adenoviral vectors expressing TK and/or CD genes were developed and tested on vascular smooth muscle cells. METHODS: Adenoviral vectors, including Ad-EF1alpha-CD-cytomegalovirus (CMV)-TK coexpressing both CD and TK double suicide genes, Ad-EF1alpha-CD and Ad-CMV-TK expressing CD and TK respectively, and control vector Ad-CMV-LacZ, were constructed and prepared with homologous recombination in RecA + E. coli cells. Integration and expression of CD and/or TK gene were identified by PCR and Western blot. Primary cultured VSMCs were infected at a multiplicity of infection (MOI) of 20 with exposure to their matching prodrugs 5-Fc and GCV. Cell mortality was measured by methyl thiazolyl tetrazolium (MTT) assays. Flow cytometry analysis was used to detect cell death. Apoptotic cells were analyzed using Hoechst 33342 fluorescence dye as a DNA probe. Genomic DNA cleavage of apoptotic VSMCs was tested by agarose gel electrophoresis. RESULTS: Recombinant adenovirus expressing CD and/or TK suicide genes were successfully constructed. Both single and double suicide genes could be integrated into adenoviral genome and expressed. Cytotoxic effects of Ad-EF1alpha-CD-CMV-TK double suicide genes combined with 5-Fc and GCV were higher than those of Ad-CMV-TK and Ad-EF1alpha-CD single gene groups. The rate of cell survival was only (9 +/- 3)% in the Ad-EF1alpha-CD-CMV-TK group, but (37 +/- 3)% in the Ad-CMV-TK and (46 +/- 4)% in the Ad-EF1alpha-CD groups (P < 0.05). Flow cytometry analysis indicated that the killing mechanisms of the groups were different. Necrosis and apoptosis were involved in the mechanism of the double gene group. Based on the DNA stainability with Hoechst 33342, the apoptotic rates of VSMCs in the Ad-EF1alpha-CD-CMV-TK [(11.0 +/- 2.1)%] and Ad-CMV-TK [(12.0 +/- 2.2)%] groups were higher than those in Ad-CMV-LacZ [(1.2 +/- 0.11)%] and Ad-EF1alpha-CD [(5.0 +/- 1.8)%] groups (P < 0.05, respectively). DNA smear could be observed in both Ad-CMV-TK and Ad-EF1alpha-CD-CMV-TK groups after administration of prodrugs. CONCLUSIONS: The killing effect on rat VSMCs mediated by adenoviral CD/TK double suicide genes is superior to that of single suicide gene. The killing mechanism of recombinant adenovirus coexpressing CD/TK double suicide genes is mainly through cytotoxic effect and apoptosis.