Single-cell transcriptome analysis reveals tumoral microenvironment heterogenicity and hypervascularization in human carotid body tumor

Carotid body tumor (CBT) is a rare neck tumor located at the adventitia of the common carotid artery bifurcation. The prominent pathological features of CBT are high vascularization and abnormal proliferation. However, single-cell transcriptome analysis of the microenvironment composition and molecular complexity in CBT has yet to be performed. In this study, we performed single-cell RNA sequencing (scRNA-seq) analysis on human CBT to define the cells that contribute to hypervascularization and chronic hyperplasia. Unbiased clustering analysis of transcriptional profiles identified 16 distinct cell populations including endothelial cells (ECs), smooth muscle cells (SMCs), neuron cells, macrophage cells, neutrophil cells, and T cells. Within the ECs population, we defined subsets with angiogenic capacity plus clear signs of later endothelial progenitor cells (EPCs) to normal ECs. Two populations of macrophages were detectable in CBT, macrophage1 showed enrichment in hypoxia-inducible factor-1 (HIF-1) and as well as an early EPCs cell-like population expressing CD14 and vascular endothelial growth factor. In addition to HIF-1-related transcriptional protein expression, macrophages1 also display a neovasculogenesis-promoting phenotype. SMCs included three populations showing platelet-derived growth factor receptor beta and vimentin expression, indicative of a cancer-associated fibroblast phenotype. Finally, we identified three types of neuronal cells, including chief cells and sustentacular cells, and elucidated their distinct roles in the pathogenesis of CBT and abnormal proliferation of tumors. Overall, our study provided the first comprehensive characterization of the transcriptional landscape of CBT at scRNA-seq profiles, providing novel insights into the mechanisms underlying its formation.

Comparative outcomes of anticoagulation alone versus anticoagulation plus endovascular intervention in adults with isolated renal vein thrombosis

BACKGROUND

Limited therapeutic strategies are available for adults with isolated renal vein thrombosis (RVT). In the present study, we explore and compare the efficacy of anticoagulation therapy alone vs anticoagulation plus endovascular intervention in the treatment of this rare disease.

METHODS

In the present study, we analyzed the clinical data of RVT patients treated in a tertiary referral center in urban China from April 2012 to April 2022. These patients were classified into anticoagulation therapy (best medical treatment [BMT]) and endovascular intervention (endovascular-based treatment [EBT]) groups. The primary end points, including thrombus clearance and renal function changes, were evaluated by measuring the serum creatinine levels and glomerular filtration rates (GFRs).

RESULTS

A total of 40 consecutive patients with RVT (25 men and 15 women) were included in the present study, with a median age of 37 years (range, 18-72 years). Some patients developed symptoms, including 12 with low back pain (30%), 11 with lower extremity edema (28%), and 10 with abdominal pain (30%). Nephrotic syndrome was the underlying etiology for most patients (30 of 40; 75%). Additionally, 28 patients (70%) developed unilateral RVT, including 18 cases of left RVT (45%). Of the 40 patients, 17 had received BMT (42%) and 23 had received EBT (58%). In the acute phase of RVT, defined as <14 days from symptom onset, the EBT group had higher thrombus clearance and better improvement of creatinine and GFR after treatment compared with the BMT group (P < .05). In the subacute phase, defined as 14 to 30 days after symptom onset, thrombus clearance was higher in the EBT group than in the BMT group (P < .05). However, the improvement in creatinine and GFR were insignificantly different between the two groups (P > .05).

CONCLUSIONS

The etiologies of RVT can and should be investigated. In the present study, RVT was primarily caused by nephrotic syndrome in young patients and also was attributed to malignancy and lupus nephritis. In addition to anticoagulation therapy, endovascular intervention, including catheter-directed thrombolysis and mechanical thrombectomy, contributed to the improvement of renal function in patients with acute RVT. Endovascular intervention markedly promoted thrombus clearance in patients in the subacute phase but did not improve renal function. Therefore, endovascular intervention should be considered if RVT is diagnosed in the acute phase.

[The mechanism of S100A7 inducing the migration and invasion in cervical cancer cells]

Objective: To investigate the mechanism of S100A7 inducing the migration and invasion in cervical cancers. Methods: Tissue samples of 5 cases of cervical squamous cell carcinoma and 3 cases of adenocarcinoma were collected from May 2007 to December 2007 in the Department of Gynecology of the Affiliated Hospital of Qingdao University. Immunohistochemistry was performed to evaluate the expression of S100A7 in cervical carcinoma tissues. S100A7-overexpressing HeLa and C33A cells were established with lentiviral systems as the experimental group. Immunofluorescence assay was performed to observe the cell morphology. Transwell assay was taken to detect the effect of S100A7-overexpression on the migration and invasion of cervical cancer cells. Reverse transcription-quantitative real-time polymerase chain reaction (RT-qPCR) was used to examine the mRNA expressions of E-cadherin, N-cadherin, vimentin and fibronectin. The expression of extracellular S100A7 in conditioned medium of cervical cancer cell was detected by western blot. Conditioned medium was added into Transwell lower compartment to detect cell motility. Exosomes were isolated and extracted from the culture supernatant of cervical cancer cell, the expressions of S100A7, CD81 and TSG101 were detected by western blot. Transwell assay was taken to detect the effect of exosomes on the migration and invasion of cervical cancer cells. Results: S100A7 expression was positively expressed in cervical squamous carcinoma and negative expression in adenocarcinoma. Stable S100A7-overexpressing HeLa and C33A cells were successfully constructed. C33A cells in the experimental group were spindle shaped while those in the control group tended to be polygonal epithelioid cells. The number of S100A7-overexpressed HeLa cells passing through the Transwell membrane assay was increased significantly in migration and invasion assay (152.00±39.22 vs 105.13±15.75, P<0.05; 115.38±34.57 vs 79.50±13.68, P<0.05). RT-qPCR indicated that the mRNA expressions of E-cadherin in S100A7-overexpressed HeLa and C33A cells decreased (P<0.05) while the mRNA expressions of N-cadherin and fibronectin in HeLa cells and fibronectin in C33A cells increased (P<0.05). Western blot showed that extracellular S100A7 was detected in culture supernatant of cervical cancer cells. HeLa cells of the experimental group passing through transwell membrane in migration and invasion assays were increased significantly (192.60±24.41 vs 98.80±47.24, P<0.05; 105.40±27.38 vs 84.50±13.51, P<0.05) when the conditional medium was added into the lower compartment of Transwell. Exosomes from C33A cell culture supernatant were extracted successfully, and S100A7 expression was positive. The number of transmembrane C33A cells incubated with exosomes extracted from cells of the experimental group was increased significantly (251.00±49.82 vs 143.00±30.85, P<0.05; 524.60±52.74 vs 389.00±63.23, P<0.05). Conclusion: S100A7 may promote the migration and invasion of cervical cancer cells by epithelial-mesenchymal transition and exosome secretion.

Identifying vulnerable plaques: A 3D carotid plaque radiomics model based on HRMRI

Background

Identification of vulnerable carotid plaque is important for the treatment and prevention of stroke. In previous studies, plaque vulnerability was assessed qualitatively. We aimed to develop a 3D carotid plaque radiomics model based on high-resolution magnetic resonance imaging (HRMRI) to quantitatively identify vulnerable plaques.

Methods

Ninety patients with carotid atherosclerosis who underwent HRMRI were randomized into training and test cohorts. Using the radiological characteristics of carotid plaques, a traditional model was constructed. A 3D carotid plaque radiomics model was constructed using the radiomics features of 3D T₁-SPACE and its contrast-enhanced sequences. A combined model was constructed using radiological and radiomics characteristics. Nomogram was generated based on the combined models, and ROC curves were utilized to assess the performance of each model.

Results

48 patients (53.33%) were symptomatic and 42 (46.67%) were asymptomatic. The traditional model was constructed using intraplaque hemorrhage, plaque enhancement, wall remodeling pattern, and lumen stenosis, and it provided an area under the curve (AUC) of 0.816 vs. 0.778 in the training and testing sets. In the two cohorts, the 3D carotid plaque radiomics model and the combined model had an AUC of 0.915 vs. 0.835 and 0.957 vs. 0.864, respectively. In the training set, both the radiomics model and the combination model outperformed the traditional model, but there was no significant difference between the radiomics model and the combined model.

Conclusions

HRMRI-based 3D carotid radiomics models can improve the precision of detecting vulnerable carotid plaques, consequently improving risk classification and clinical decision-making in patients with carotid stenosis.

Localized Elevation of Wall Shear Stress Is Linked to Recent Symptoms in Patients with Carotid Stenosis

<b><i>Background:</i></b> Estimation of symptomatic and asymptomatic carotid atherosclerosis differences can be the basis for prevention and management of carotid artery stenosis disease. In clinical practice, carotid plaque vulnerability is assessed only on the basis of luminal stenosis. However, the evolution of carotid plaque from an asymptomatic state to a symptomatic one is a complex process and the underlying hemodynamic mechanisms are unknown. We aimed to investigate the differences in hemodynamic parameters between patients with recently symptomatic carotid stenosis and asymptomatic ones. <b><i>Methods:</i></b> Hemodynamic simulations were performed on 26 carotid plaques from 25 patients with carotid artery stenosis ≥50%, 16 of whom had recent cerebrovascular ischemic events. Using human-specific flow parameters and 3D reconstruction of carotid computed tomography angiography images, we assessed hemodynamic characteristics such as wall shear stress (WSS), time-averaged WSS (TAWSS), oscillatory shear index, and relative residence time (RRT) during the cardiac cycle in patients with and without symptoms. <b><i>Results:</i></b> We found that symptomatic carotid stenosis patients had greater local TAWSS (99.59 ± 26.29 vs. 60.40 ± 20.46 dyn/cm², <i>p</i> = 0.0007) and maximal WSS (116.65 ± 39.11 vs. 68.28 ± 23.67 dyn/cm², <i>p</i> = 0.003), but lower RRT (0.019 ± 0.006 vs. 0.013 ± 0.069 s, <i>p</i> = 0.049), than asymptomatic patients, but this hemodynamic difference was not associated with carotid stenosis severity (<i>p</i> = 0.70). Patients with transient ischemic attack (TIA) or stroke had higher local TAWSS and WSSmax than patients with asymptomatic stenosis (<i>p</i> &#x3c; 0.05). Subgroup analysis showed that there was no statistical difference in local hemodynamic variables between TIA and stroke patients with carotid artery stenosis. <b><i>Conclusions:</i></b> Patients with carotid artery stenosis are more likely to experience acute ischemic cerebrovascular accidents if they have higher WSS. Simultaneous assessment with hemodynamic parameters like WSS along with stenosis severity may aid risk stratification in patients with asymptomatic carotid artery stenosis.

Causal roles of daytime sleepiness in cardiometabolic diseases and osteoporosis

OBJECTIVE

Daytime sleepiness has some association with cardiometabolic diseases and osteoporosis, but it is unknown whether their relationship is causal. This two-sample Mendelian randomization (MR) study aims to explore their causal relationship.

MATERIALS AND METHODS

We included the largest genome-wide association studies (GWASs) associated with daytime sleepiness, cardiometabolic diseases and osteoporosis. 34 single nucleotide polymorphisms (SNPs) were used as the instrumental variables of daytime sleepiness.

RESULTS

Genetic predisposition to excessive daytime sleepiness was strongly associated with increased risk of coronary artery disease (beta-estimate: 0.610, 95% confidence interval [CI]: 0.128 to 1.093, standard error [SE]: 0.246, p-value=0.013) and may increase the incidence of type 2 diabetes (beta-estimate: 0.614, 95% CI: 0.009 to 1.219, SE: 0.309, p-value=0.047). We found no causal influence of daytime sleepiness on heart failure, atrial fibrillation, cerebral ischemia, intracerebral hemorrhage, forearm bone mineral density (FA-BMD), femoral neck BMD (FN-BMD), and lumbar spine BMD (LS-BMD).

CONCLUSIONS

This study suggested that excessive daytime sleepiness was causally associated with increased risk of coronary artery disease, which may benefit to prevent this disease.

TP53 /KRAS Co-Mutations Create Divergent Prognosis Signatures in Intrahepatic Cholangiocarcinoma

Background: Due to high invasiveness and heterogeneity, the morbidity and mortality of intrahepatic cholangiocarcinoma (ICC) remain unsatisfied. Recently, the exploration of genomic variants has decoded the underlying mechanisms of initiation and progression for multiple tumors, while has not been fully investigated in ICC.

Methods: We comprehensively analyzed 899 clinical and somatic mutation data of ICC patients from three large-scale cohorts. Based on the mutation landscape, we identified the common high-frequency mutation genes (FMGs). Subsequently, the clinical features, prognosis, tumor mutation burden (TMB), and pharmacological landscape from patients with different mutation carriers were further analyzed.

Results: We found TP53 and KRAS were the common FMGs in the three cohorts. Kaplan–Meier survival curves and univariate and multivariate analysis displayed that TP53 and KRAS mutations were associated with poor prognosis. Considering the co-mutation phenomenon of TP53 and KRAS, we stratified patients into “Double-WT,” “Single-Hit,” and “Double-Hit” phenotypes by mutation status. Patients with the three phenotypes showed significant differences in the mutation landscape. Additionally, compared with “Double-WT” and “Single-Hit” phenotypes, patients with “Double-Hit” presented a dismal prognosis and significantly high TMB. Through chemotherapy sensitivity analysis, we identified a total of 30 sensitive drugs for ICC patients, of which 22 were drugs sensitive to “Double-WT,” 7 were drugs sensitive to “Double-Hit,” and only one was a drug sensitive to “Single-Hit.”

Conclusion: Our study defined a novel mutation classification based on the common FMGs, which may contribute to the individualized treatment and management of ICC patients.

Development and Validation of Ischemic Events Related Signature After Carotid Endarterectomy

Background: Ischemic events after carotid endarterectomy (CEA) in carotid artery stenosis patients are unforeseeable and alarming. Therefore, we aimed to establish a novel model to prevent recurrent ischemic events after CEA.

Methods: Ninety-eight peripheral blood mononuclear cell samples were collected from carotid artery stenosis patients. Based on weighted gene co-expression network analysis, we performed whole transcriptome correlation analysis and extracted the key module related to ischemic events. The biological functions of the 292 genes in the key module were annotated via GO and KEGG enrichment analysis, and the protein-protein interaction (PPI) network was constructed via the STRING database and Cytoscape software. The enrolled samples were divided into train (n = 66), validation (n = 28), and total sets (n = 94). In the train set, the random forest algorithm was used to identify critical genes for predicting ischemic events after CEA, and further dimension reduction was performed by LASSO logistic regression. A diagnosis model was established in the train set and verified in the validation and total sets. Furthermore, fifty peripheral venous blood samples from patients with carotid stenosis in our hospital were used as an independent cohort to validation the model by RT-qPCR. Meanwhile, GSEA, ssGSEA, CIBERSORT, and MCP-counter were used to enrichment analysis in high- and low-risk groups, which were divided by the median risk score.

Results: We established an eight-gene model consisting of PLSCR1, ECRP, CASP5, SPTSSA, MSRB1, BCL6, FBP1, and LST1. The ROC-AUCs and PR-AUCs of the train, validation, total, and independent cohort were 0.891 and 0.725, 0.826 and 0.364, 0.869 and 0.654, 0.792 and 0.372, respectively. GSEA, ssGSEA, CIBERSORT, and MCP-counter analyses further revealed that high-risk patients presented enhanced immune signatures, which indicated that immunotherapy may improve clinical outcomes in these patients.

Conclusion: An eight-gene model with high accuracy for predicting ischemic events after CEA was constructed. This model might be a promising tool to facilitate the clinical management and postoperative surveillance of carotid artery stenosis patients.

EGR1 and KLF4 as Diagnostic Markers for Abdominal Aortic Aneurysm and Associated With Immune Infiltration

Background

Formation and rupture of abdominal aortic aneurysm (AAA) is fatal, and the pathological processes and molecular mechanisms underlying its formation and development are unclear. Perivascular adipose tissue (PVAT) has attracted extensive attention as a newly defined secretory organ, and we aim to explore the potential association between PVAT and AAA.

Methods

We analyzed gene expression and clinical data of 30 PVAT around AAA and 30 PVAT around normal abdominal aorta (NAA). The diagnostic markers and immune cell infiltration of PVAT were further investigated by WGCNA, CIBERSORT, PPI, and multiple machine learning algorisms (including LASSO, RF, and SVM). Subsequently, eight-week-old C57BL/6 male mice (n = 10) were used to construct AAA models, and aorta samples were collected for molecular validation. Meanwhile, fifty-five peripheral venous blood samples from patients (AAA vs. normal: 40:15) in our hospital were used as an inhouse cohort to validate the diagnostic markers by qRT-PCR. The diagnostic efficacy of biomarkers was assessed by receiver operating characteristic (ROC) curve, area under the ROC (AUC), and concordance index (C-index).

Results

A total of 75 genes in the Grey60 module were identified by WGCNA. To select the genes most associated with PVAT in the grey60 module, three algorithms (including LASSO, RF, and SVM) and PPI were applied. EGR1 and KLF4 were identified as diagnostic markers of PVAT, with high accurate AUCs of 0.916, 0.926, and 0.948 (combined two markers). Additionally, the two biomarkers also displayed accurate diagnostic efficacy in the mice and inhouse cohorts, with AUCs and C-indexes all >0.8. Compared with the NAA group, PVAT around AAA was more abundant in multiple immune cell infiltration. Ultimately, the immune-related analysis revealed that EGR1 and KLF4 were associated with mast cells, T cells, and plasma cells.

Conclusion

EGR1 and KLF4 were diagnostic markers of PVAT around AAA and associated with multiple immune cells.

Integrated Analysis of Multi-Omics Alteration, Immune Profile, and Pharmacological Landscape of Pyroptosis-Derived lncRNA Pairs in Gastric Cancer

Background: Recent evidence demonstrates that pyroptosis-derived long non-coding RNAs (lncRNAs) have profound impacts on the initiation, progression, and microenvironment of tumors. However, the roles of pyroptosis-derived lncRNAs (PDLs) in gastric cancer (GC) remain elusive.

Methods: We comprehensively analyzed the multi-omics data of 839 GC patients from three independent cohorts. The previous gene set enrichment analysis embedding algorithm was utilized to identify PDLs. A gene pair pipeline was developed to facilitate clinical translation via qualitative relative expression orders. The LASSO algorithm was used to construct and validate a pyroptosis-derived lncRNA pair prognostics signature (PLPPS). The associations between PLPPS and multi-omics alteration, immune profile, and pharmacological landscape were further investigated.

Results: A total of 350 PDLs and 61,075 PDL pairs in the training set were generated. Cox regression revealed 15 PDL pairs associated with overall survival, which were utilized to construct the PLPPS model via the LASSO algorithm. The high-risk group demonstrated adverse prognosis relative to the low-risk group. Remarkably, genomic analysis suggested that the lower tumor mutation burden and gene mutation frequency (e.g., TTN, MUC16, and LRP1B) were found in the high-risk group patients. The copy number variants were not significantly different between the two groups. Additionally, the high-risk group possessed lower immune cell infiltration abundance and might be resistant to a few chemotherapeutic drugs (including cisplatin, paclitaxel, and gemcitabine).

Conclusion: PDLs were closely implicated in the biological process and prognosis of GC, and our PLPPS model could serve as a promising tool to advance prognostic management and personalized treatment of GC patients.

Congenital Abdominal Aortic Aneurysm: A Case Report and Literature Review

Congenital abdominal aortic aneurysm is a rare disease with unknown etiology, and the common symptoms are abdominal pulsatile mass and pain caused by aneurysm rupture. The disease has a high mortality rate and fewer reports of surgical treatment. Here, we present a case of an idiopathic congenital abdominal aortic aneurysm. A 4-year-old boy had an abdominal pulsatile mass, and computed tomography angiography revealed an isolated infrarenal abdominal aortic aneurysm. To prevent rupture of the aneurysm, we repaired the aneurysm with artificial graft transplantation. No genetic mutation of the known congenital aneurysmal diseases was found in the whole-exome sequencing of the patient and his parents. There was no graft obstruction, and the patient grew well 40 months after surgery. Open surgery is the best treatment for idiopathic congenital abdominal aortic aneurysms. Surgical details such as timing and graft selection need to be further explored.

High-Efficiency Arbitrary Quantum Operation on a High-Dimensional Quantum System

The ability to manipulate quantum systems lies at the heart of the development of quantum technology. The ultimate goal of quantum control is to realize arbitrary quantum operations (AQUOs) for all possible open quantum system dynamics. However, the demanding extra physical resources impose great obstacles. Here, we experimentally demonstrate a universal approach of AQUO on a photonic qudit with the minimum physical resource of a two-level ancilla and a log_{2}d-scale circuit depth for a d-dimensional system. The AQUO is then applied in a quantum trajectory simulation for quantum subspace stabilization and quantum Zeno dynamics, as well as incoherent manipulation and generalized measurements of the qudit. Therefore, the demonstrated AQUO for complete quantum control would play an indispensable role in quantum information science.

Differentially Expressed MicroRNAs Associated with Vein Graft Restenosis in Rats

Objective: Intimal hyperplasia is the main cause of restenosis of vein grafts after venous transplantation. MicroRNAs are considered to play a role in vein graft restenosis; however, the expression profile of microRNAs in neointima has not been reported in detail. We wanted to investigate the differentially expressed microRNAs in the restenosis of vein grafts in rats.Methods: We established a rat model for vein transplantation to explore the pathogenic roles of microRNAs during intimal hyperplasia. Hematoxylin and eosin staining was used to confirm intimal hyperplasia in the vein grafts. Changes in microRNA expression in the vein grafts were detected 3 and 14 days after surgery by sequencing, reverse transcription‐quantitative polymerase chain reaction, and bioinformatics analyses for functional annotation.Results: We detected 711 newly predicted microRNAs among all the comparisons. Among these comparisons, 437 differentially expressed microRNAs were detected in the postoperative day 3 group versus the control group, 265 were detected in the postoperative day 14 group versus the control group, and 158 were detected in the postoperative day 14 group versus the postoperative day 3 group. Pathway analysis revealed significant enrichment of target genes that mediate Wnt, mitogen-activated protein kinase, vascular smooth muscle contraction, and regulation of actin cytoskeleton signaling.Conclusion: Our results provide insight into the pathogenesis of restenosis and will help develop novel targets in the prevention and treatment of vein graft restenosis.

Experimental Implementation of Universal Nonadiabatic Geometric Quantum Gates in a Superconducting Circuit

Using geometric phases to realize noise-resilient quantum computing is an important method to enhance the control fidelity. In this work, we experimentally realize a universal nonadiabatic geometric quantum gate set in a superconducting qubit chain. We characterize the realized single- and two-qubit geometric gates with both quantum process tomography and randomized benchmarking methods. The measured average fidelities for the single-qubit rotation gates and two-qubit controlled-Z gate are 0.9977(1) and 0.977(9), respectively. Besides, we also experimentally demonstrate the noise-resilient feature of the realized single-qubit geometric gates by comparing their performance with the conventional dynamical gates with different types of errors in the control field. Thus, our experiment proves a way to achieve high-fidelity geometric quantum gates for robust quantum computation.

Early and midterm outcomes of in situ laser fenestration during thoracic endovascular aortic repair for acute and subacute aortic arch diseases and analysis of its complications

OBJECTIVE

An analysis was conducted of early and midterm outcomes of a large series of patients treated with in situ laser fenestration (ISLF) during thoracic endovascular aortic repair (TEVAR) of acute and subacute complex aortic arch diseases, such as Stanford type A aortic dissection (TAAD), type B aortic dissection (TBAD) requiring proximal sealing at zone 2 or more proximal, thoracic aortic aneurysm or pseudoaneurysm, and penetrating aortic ulcer. We present the perioperative and follow-up outcomes and discuss the rate of complications.

METHODS

This is a retrospective review of prospectively collected data from January 2017 to March 2019 of patients treated with TEVAR and ISLF of aortic arch branches at a large tertiary academic institution in an urban city in China. Preoperative, intraoperative, and follow-up clinical and radiographic data are analyzed and discussed.

RESULTS

A total of 148 patients presented with symptomatic and acute or subacute TAAD, TBAD, thoracic aortic aneurysm, or penetrating aortic ulcer for a total of 183 arch vessels. There were 105 men and 43 women, 21 to 79 years of age (mean, 54.9 ± 12.9 years). Time from symptom onset to time of surgery was an average of 7 ± 3 days. Survivor follow-up duration ranged from 5 to 24 months (mean, 15 ± 5 months). Single-vessel fenestration was carried out in 124 cases, two-vessel fenestration in 13 cases, and three-vessel fenestration in 11 cases. There were four cases with technical failure to laser fenestration, with a technical success rate of 97.3%. Postoperatively, there were seven cases of endoleak (4.7%; one type IB distal from the left subclavian artery branch stent graft, three type IIIC at the fenestration site, and three type II), three retrograde dissections (2.0%), and five strokes (3.4%); death occurred in three patients with 30-day mortality of 2.9%, and two deaths occurred during follow-up for 3.4% mortality at an average 15 months of follow-up. There was no branch stent graft occlusion or spinal ischemia postoperatively or during follow-up. The distribution of arch diseases varied significantly according to the number of vessels that were laser fenestrated; TAAD was more likely to receive multivessel laser fenestrations, and TBAD was more likely to receive single-vessel fenestration (P < .001). The rate of complications was distributed differently between the three ISLF groups, with more complications occurring in multivessel fenestrations. However, a statistical weakening was observed when frequency of complications between the three groups was stratified by type of arch disease. The complication rate varied significantly between the different arch diseases, higher in TAAD than in TBAD (P = .008).

CONCLUSIONS

ISLF during TEVAR for treatment of acute and subacute complex aortic arch diseases in the proximal aortic arch is safe and effective on the basis of these early to midterm follow-up data of a large cohort. However, care should be taken in intervening on TAAD using TEVAR with adjunctive multivessel laser fenestration. Continued investigation of TEVAR and adjunctive ISLF is needed to elucidate the long-term outcomes of this minimally invasive treatment for complex aortic arch disease in an urgent setting.

A new adaptation for in vitro co-culture of single porcine parthenogenetic embryos using feeder cells

Feeder cells can promote cell proliferation and help overcome the developmental arrest of early embryos by producing growth factors. The objective of this study was to evaluate the effects of feeder cells on the development of all single porcine parthenogenetic embryos in vitro. Firstly, we showed that the cleavage and blastocyst formation rate of all single procine parthenogenetic embryos co-cultured with feeder cells increased in contrast to those cultured without feeder cells (p⟨0.05). However, no statistically significant differences were observed between the blastocyst formation rate in the embryos co-cultured with 3 different kinds feeder cells namely oviduct epithelial feeder cells, granulose feeder cells and porcine fetal fibroblast feeder cells (p>0.05). Secondly, highly significant differences were observed between the cleavage and blastocyst formation rate (p⟨0.05) when the embryos were co-cultured with oviduct epithelial feeder cells in different volume drops ranging from 3 to 20 μL and the cleavage rate were the highest when cultured in 5 μL drops. Thirdly, the tempospacial pattern of the development of single embryos co-cultured with oviduct epithelial feeder cells was consistent with that of traditional multi-embryo culture, indicating that the co-culturing does not affect the developmental competence of the porcine parthenogenetic embryos. Finally, highly significant differences were observed between the cleavage and blastocyst formation rate with and without zona pellucida in vitro (p⟨0.05). In this study, a new adaption of in vitro co-culture of single porcine parthenogenetic embryos using feeder cells has been successfully established and this will facilitate further investigations to discover the mechanistic mode of developmental arrest of porcine embryos.

Knockdown of microRNA-181a inhibits osteosarcoma cells growth and invasion through triggering NLRP3-dependent pyroptosis

OBJECTIVE

This study aimed to investigate the physiological function and molecular mechanism of microRNA-181a (miRNA-181a) in the carcinogenesis of osteosarcoma.

MATERIALS AND METHODS

The relative expression of miRNA-181a in tissues and cultured cells was detected by quantitative real time-polymerase chain reaction (qRT-PCR). MiR-181a inhibitor and miR-181a mimics were used to manipulate its level in cells. Cell proliferation and invasion were measured using Cell Counting Kit-8 (CCK-8) assay and transwell assay, respectively. The protein levels of the targeted genes were detected by Western blotting and immunohistochemistry. Terminal Deoxynucleotidyl Transferase (TdT)-mediated dUTP Nick-End Labeling (TUNEL) assay was employed to detect cell apoptosis. Moreover, a xenograft tumor bearing mice model was used to evaluate the effect of miR-181a in vivo.

RESULTS

We found that miRNA-181a was aberrantly elevated in osteosarcoma tissues and cells. Moreover, the overexpression of miRNA-181a could facilitate cell proliferation and migration. By contrast, miRNA-181a knockdown reverses these effects. Additionally, downregulation of miRNA-181a could activate NOD-like receptor protein 3 (NLRP3)-dependent pyroptosis, as evidenced by the increase of pyroptosis-related genes (NLRP3, caspase-1, interleukin-18, and interleukin-1β) in miRNA-181a inhibitor transfected cells compared with the control. Further mechanistic studies identified that miRNA-181a knockdown suppresses cell proliferation and invasion by activating NLRP3-dependent pyroptosis. Silencing NLRP3 could effectively reverse the effects mediated by miRNA-181a inhibitor. Consistently, in vitro results also demonstrated that blockade of miRNA-181a notably suppresses tumor growth via activating pyroptosis.

CONCLUSIONS

These results provide that miRNA-181a might serve as potential therapeutic target for osteosarcoma patients.

Endovascular treatment for left innominate vein aneurysm: Case report and literature review

Innominate vein aneurysms originating from the mediastinum are very rare. Previous treatments for this condition often required thoracotomy. We report a case of a 43-year-old male who presented a mediastinal mass by chest radiography. Contrast-enhanced CT and venography confirmed the diagnosis of left innominate vein aneurysm. The patient underwent endovascular treatment with stent placement and coil embolization of the left innominate vein. The patient remains well 18 months after surgery. The objective of this report is to discuss the diagnosis and endovascular treatment results of innominate vein aneurysm and to review the relevant literature to enhance and expand the pool of knowledge for this abnormality.

CO2 concentration affects in vitro pig embryo developmental capacity

Culture gas atmosphere is one of the most important factors affecting embryo development in vitro. The main objective of this study was to compare the effects of CO concentration on the subsequent pre-implantation developmental capacity of pig embryos in vitro, including embryos obtained via parthenogenesis, in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI). Pig embryos were developed in four different CO2 concentrations in air: 3%, 5%, 10%, or 15%. The cleavage rate of pig parthenogenetic, IVF, or ICSI embryos developed in CO2 concen- trations under 5% was the highest. There were no significant differences in the oocyte cleavage rate in ICSI embryos in CO2 concentrations under 3% and 5% (p>0.05). However, as CO2 levels increased (up to 15%) the blastocyst output on day 7, from parthenogenetic, IVF, and ICSI em- bryos, decreased to 0%. These findings demonstrate that CO2 positively affects the developmen- tal capacity of pig embryos. However, high or low CO2 levels do not significantly improve the developmental capacity of pig embryos. The best results were obtained for all of the pig embryos at a 5% CO2 concentration.

Attenuated Salmonella VNP20009 mutant (ΔhtrA) is a promising candidate for bacteria-mediated tumour therapy in hosts with TNFR1 deficiency

VNP20009 is a genetically modified strain of Salmonella typhimurium and has a good anticancer effect wildly used in tumour therapy on animal models. For its clinical application, an accurate bio-safety assessment on sensitive models is necessary. In this study, we use TNFR1 KO mice as a susceptive model to assess the virulence of bacterial VNP20009 and its derivative ΔhtrA. By intraperitoneal administration of Salmonella, the increased lethality was observed in TNFR1 KO mice infected with VNP20009, but not with ΔhtrA. We performed a systemically comparative analysis of their toxicity, and ΔhtrA shows a better bio-safety for TNFR1 KO mice. Since the macrophages with TNFR1 deficiency exhibit a reduced ability of bacteria clearance, ΔhtrA with lower survival ability in normal macrophages restores its viability in TNFR1 KO macrophages. Thus, ΔhtrA was further tested for its antitumour effect in TNFR1 KO mice bearing a B16F10 melanoma model. It displays a moderate antitumour effect, suggesting ΔhtrA instead of VNP20009 might be a promising candidate for bacteria-mediated tumour therapy specific to those with low immunity.

SIGNIFICANT AND IMPACT OF THE STUDY

VNP20009 is attenuated Salmonella with a good safety widely used for tumour-targeting bacterial therapies. Little is known about its toxicity in hosts with low immunity. This study is the first systemically comparative analysis of their toxicity of VNP20009 and its mutant ΔhtrA in TNFR1-KO mice. Research on toxicity of tumour-targeting Salmonella in mice with immunodeficiency can facilitate the optimization of bacterial therapies with reduced adverse effects in future clinical trials.

[S100A7 promotes the metastasis and epithelial-mesenchymal transition on HeLa and CaSki cells]

Objective: To elucidate the impact of over-expression of S100A7 on migration, invasion, proliferation, cell cycle, and epithelial-mesenchymal transition (EMT) in human cervical cancer HeLa and CaSki cells. Methods: (1) Immunohistochemistry of SP was used to examine the expression of S100A7 in 40 cases of squamous cervical cancer tissues and 20 cases of normal cervical tissues. (2) The vectors of pLVX-IRES-Neo-S100A7 and pLVX-IRES-Neo were used to transfect human cervical cancer HeLa and CaSki cells, and the positive clones were screened and identified. Next, transwell migration assay, cell counting kit-8 (CCK-8) assay and fluorescence activating cell sorter (FACS) were used to detect the effect of S100A7-overexpression on the migration, invasion, proliferation and cell cycle of cervical cancer cells. Furthermore, western blot was performed to observe the expression of epithelial marker (E-cadherin) and mesenchymal markers (N-cadherin, vimentin, and fibronectin) of EMT. Results: (1) S100A7 expression was significantly higher in cervical squamous cancer tissues (median 91.6) than that in normal cervical tissues (median 52.1; Z=-2.948, P=0.003) . (2) Stable S100A7-overexpressed cells were established using lentiviral-mediated gene delivery in HeLa and CaSki cells. S100A7 was detected by real-time quantitative reverse transcription PCR, S100A7 mRNA of S100A7-overexpressed cells were 119±3 and 177±16, increased significantly compared with control groups of median (P<0.01) . Compared with the control cells, the number of S100A7-overexpressed HeLa and CaSki cells that passed the transwell membrane assay were increased significanatly (572±51 vs 337±25, P<0.01; 100±8 vs 41±4, P<0.01) .Matrigel invasion assay showed that the number of S100A7-overexpressed HeLa and CaSki cells that passed the transwell membrane were respectively 441±15 and 110±14, elevated significantly compared with control cells (156±21 and 59±7; P<0.05) . However, S100A7 overexpression didn't influence the proliferation and cell cycle progression of HeLa and CaSki cells (P>0.05) . Expression of E-cadherin was dramatically decreased, while N-cadherin, vimentin, and fibronectin increased in S100A7-overexpressed cells. Conclusion: S100A7 enhances the migration, invasion and EMT of HeLa cells and CaSki cells, and may be plays an important role in the development of cervical cancer.

A protective role for FADD dominant negative (FADD-DN) mutant in trinitrochlorobenzene (TNCB)-induced murine contact hypersensitivity reactions

BACKGROUND

Fas-associated protein with death domain (FADD) is a classic adaptor protein in apoptosis. Increasing evidence has shown that FADD is also implicated in T-cell development, activation and proliferation. The role of FADD in inflammatory disorders remains largely unexplored.

AIM

To assess the role of FADD in inflammatory disorders.

METHODS

We established an experimental model of contact hypersensitivity (CHS) by using 2,4,6-trinitrochlorobenzene (TNCB) on transgenic mice expressing a dominant negative mutant of FADD (FADD-DN), RESULTS: CHS responses were clearly attenuated in FADD-DN mice compared with control mice. In the retroauricular lymph nodes, the ratio of CD8+ T cells was also decreased.

CONCLUSION

FADD-DN appears to play a protective role in TNCB-induced CHS reactions.

Constraints on cosmic strings from the LIGO-Virgo gravitational-wave detectors

Cosmic strings can give rise to a large variety of interesting astrophysical phenomena. Among them, powerful bursts of gravitational waves (GWs) produced by cusps are a promising observational signature. In this Letter we present a search for GWs from cosmic string cusps in data collected by the LIGO and Virgo gravitational wave detectors between 2005 and 2010, with over 625 days of live time. We find no evidence of GW signals from cosmic strings. From this result, we derive new constraints on cosmic string parameters, which complement and improve existing limits from previous searches for a stochastic background of GWs from cosmic microwave background measurements and pulsar timing data. In particular, if the size of loops is given by the gravitational backreaction scale, we place upper limits on the string tension Gμ below 10(-8) in some regions of the cosmic string parameter space.

Adenosine 5'-monophosphate ameliorates D-galactosamine/lipopolysaccharide-induced liver injury through an adenosine receptor-independent mechanism in mice

D-galactosamine (GalN)/lipopolysaccharide (LPS)-induced lethality and acute liver failure is dependent on endogenously produced inflammatory cytokines. Adenosine has been proven to be a central role in the regulation of inflammatory response. It is not entirely clear that which adenosine action is actually crucial to limiting inflammatory tissue destruction. Here we showed that GalN/LPS challenge elevated hepatic adenosine and induced lethality in adenosine receptor-deficient mice with equal efficiency as wild-type mice. In GalN/LPS-treated mice, pretreatment with adenosine 5'-monophosphate (5'-AMP) significantly elevated hepatic adenosine level and reduced mortality through decreasing cytokine and chemokine production. In RAW264.7 cells, 5'-AMP treatment inhibited the production of inflammatory cytokines, which is not mediated through adenosine receptors. 5'-AMP failed to attenuate LPS-induced nuclear factor-κB (NF-κB) p65 nuclear translocation, but reduced LPS-induced recruitment of NF-κB p65 to inflammatory gene promoters and decreased LPS-induced enrichment of H3K4 dimethylation at the tumor necrosis factor-α (TNF-α) promoter, which was involved in 5'-AMP-induced elevation of cellular adenosine and a decline of methylation potential. In vitro biochemical analysis revealed that adenosine directly attenuated recruitment of NF-κB to the TNF-α and interleukin-6 promoters. Our findings demonstrate that 5'-AMP-inhibiting inflammatory response is not mediated by adenosine receptors and it may represent a potential protective agent for amelioration of LPS-induced liver injury.

Evaluation of CT coronary artery angiography with 320-row detector CT in a high-risk population

OBJECTIVES

The aim of this article was to prospectively evaluate the accuracy and radiation dose of 320-detector row dynamic volume CT (DVCT) for the detection of coronary artery disease (CAD) in a high-risk population.

METHODS

60 patients with a high risk of CAD underwent DVCT without preceding heart rate control and also underwent invasive coronary angiography (ICA), which served as the standard reference.

RESULTS

On a per segment analysis, overall sensitivity was 95.3%, specificity was 97.6%, positive predictive value was 90.6%, negative predictive value was 98.8% and Youden index was 0.93. In both heart rate subgroups, diagnostic accuracy for the assessment of coronary artery stenosis was similar. The accuracy of the subgroup with an Agatston score ≥100 was lower than that for patients with an Agatston score <100. However, the difference between DVCT and ICA results was not significant (p=0.08). The mean estimated effective dose of CT was 12.5 ± 9.4 mSv. In those patients with heart rates less than 70 beats per minute (bpm), the mean radiation exposure of DVCT was 5.2 ± 0.9 mSv. The effective radiation dose was significantly lower than that of ICA (14.1 ± 5.9 mSv) (p<0.001). When the heart rate was >70 bpm, a significantly higher dose was delivered to patients with DVCT (22.6 ± 5.2 mSv, p<0.001) than with ICA (15.0 ± 5.3 mSv, p<0.001).

CONCLUSION

DVCT reliably provides high diagnostic accuracy without heart rate/rhythm control. However, from a dosimetric point of view, it is recommended that heart rate should be controlled to <70 bpm to decrease radiation dose.

Therapeutic effects of anticoagulant agents on preeclampsia in a murine model induced by phosphatidylserine/phosphatidylcholine microvesicles

Preeclampsia (PE) is a placenta-mediated pregnancy complication that results in high maternal and neonatal mortality and morbidity worldwide. Currently, there is no satisfactory pharmacotherapeutic treatment to stop the PE progression. In this study, we investigated the therapeutic effects of anticoagulant agents, including annexin V, heparin, and a fusion protein of annexin V and hirudin (AND), in a murine PE model induced by intravenous injection of phosphatidylserine/phosphatidylcholine (PS/PC) microvesicles. Compared with the control pregnant animals, the pregnant mice injected with PS/PC presented PE-like symptoms, including elevated systolic blood pressure, proteinuria, and reduction of antithrombin III and blood platelets. However, the PE-like symptoms were significantly alleviated after the PS/PC-injected mice were treated with annexin V, AND, or heparin. Furthermore, fibrin deposition in the placentas in the anticoagulant treated mice was remarkably improved, compared with that in the mice injected with PS/PC alone. The data demonstrate that anticoagulants are effective to prevent the occurrence of PE in the murine model and also suggest that hypercoagulation in the placenta is a contributing factor in the pathogenesis of PE.

Treatment of Chronic Idiopathic Urticaria with Levamisole: A Multicentre, Randomized, Double-Blind, Controlled Trial

The objective of this study was to evaluate the efficacy of treating chronic idiopathic urticaria (CIU) with levamisole in combination with levocetirizine. This was a multicentre, randomized, double-blind, controlled trial that included 132 patients with active CIU who were treated for 6 weeks with either levocetirizine alone (control group; n = 65) or levamisole plus levocetirizine (treatment group; n = 67). Response to therapy was evaluated by measuring the efficacy rate. After 2 weeks of treatment, there was no significant difference in the efficacy rate between the treatment and control groups (54.84% and 42.37%, respectively). After 6 weeks of treatment, a statistically significant difference in the efficacy rate was observed between the groups (76.27% and 54.39% for the treatment and control groups, respectively). This study demonstrated that a combination of levamisole plus levocetirizine is more effective than levocetirizine alone and potentially provides a new, promising approach to the treatment of CIU.

Effect of dendritic cell vaccine against a tongue squamous cell cancer cell line (Tca8113) in vivo and in vitro

Dendritic cells (DCs), as primary antigen-presenting cells with the capacity to activate naïve T lymphocytes, are considered to be promising adjuvants for immunity against cancer. In this study, the effect of T lymphocyte-mediated immunity induced by a DC vaccine against Tca8113 cells in vivo and in vitro was evaluated. DCs were from human peripheral blood monocytes cultured in the presence of granulocyte-macrophage colony stimulating factor, interleukin 4 and/or tumour necrosis factor alpha, and stimulated with Tca8113 cell lysate prepared by the freeze-thaw method. The autologous T cells activated by these DCs were used in an in vitro MTT assay to detect their tumouricidal activity and investigated for their anti-tumour effect in vivo by administration to nude mice with implanted tumours (Tca8113). An adequate number of DCs were successfully generated from the monocytes. The T cells activated by the DC-based vaccine killed Tca8113 cells in vitro (P<0.01), postponed tumour doubling time of the implanted tumours in nude mice (P<0.01) and inhibited the growth of the tumours (P<0.05). These results show that DCs from monocytes induce a lymphocyte-mediated immune response against tongue squamous carcinoma, and could be used as a vehicle for tumour antigens.

[Exploration on statistical method for calculating intensity of the infection in residents in nationwide sampling survey of schistosomiasis]

AIM

To set up statistical methods for calculation of intensity of schistosome infection in residents in nationwide sampling survey of schistosomiasis.

METHODS

Based on the epidemiological survey of schistosomiasis and according to the medical statistics for multiple stratifying and clustering random sampling, the calculation method on intensity of schistosome infection was inferred.

RESULTS AND CONCLUSION

Nine formulas were worked out for the calculation of the intensity of schistosome infection in different endemic provinces with different ecotypes. These formulas are of practical value.

The crystal structure of bar-headed goose hemoglobin in deoxy form: the allosteric mechanism of a hemoglobin species with high oxygen affinity

The crystal structure of a high oxygen affinity species of hemoglobin, bar-headed goose hemoglobin in deoxy form, has been determined to a resolution of 2.8 A. The R and R(free) factor of the model are 0.197 and 0.243, respectively. The structure reported here is a special deoxy state of hemoglobin and indicates the differences in allosteric mechanisms between the goose and human hemoglobins. The quaternary structure of the goose deoxy hemoglobin shows obvious differences from that of human deoxy hemoglobin. The rotation angle of one alphabeta dimer relative to its partner in a tetramer molecule from the goose oxy to deoxy hemoglobin is only 4.6 degrees, and the translation is only 0.3 A, which are much smaller than those in human hemoglobin. In the alpha(1)beta(2) switch region of the goose deoxy hemoglobin, the imidazole ring of His beta(2)97 does not span the side-chain of Thr alpha(1)41 relative to the oxy hemoglobin as in human hemoglobin. And the tertiary structure changes of heme pocket and FG corner are also smaller than that in human hemoglobin. A unique mutation among avian and mammalian Hbs of alpha119 from proline to alanine at the alpha(1)beta(1 )interface in bar-headed goose hemoglobin brings a gap between Ala alpha119 and Leu beta55, the minimum distance between the two residues is 4.66 A. At the entrance to the central cavity around the molecular dyad, some residues of two beta chains form a positively charged groove where the inositol pentaphosphate binds to the hemoglobin. The His beta146 is at the inositol pentaphosphate binding site and the salt-bridge between His beta146 and Asp beta94 does not exist in the deoxy hemoglobin, which brings the weak chloride-independent Bohr effect to bar-headed goose hemoglobin.

The nuclear localization signal of zebrafish terra is located within the DM domain

Zebrafish Terra is a member of the DM domain-containing transcription factor family and is involved in somitogenesis. The other known members of this family play a role in sex differentiation across species from Caenorhabditis elegans to human. Using the green fluorescence protein-Terra fusion constructs, we have identified the nuclear localization signal (NLS) of terra by transfecting human HeLa cells. The terra NLS is located between the two intertwined zinc-binding sites of the DNA-binding domain. However, the nuclear translocation of terra is independent of the structure required for DNA binding. Mutational analysis demonstrates that basic residues K77 and R78 within the DM domain are absolutely required for the translocation of Terra into the nuclei. Sequence comparison discloses that the NLS of Terra is also present in the other known members of the DM family, indicating the conservative nature of the NLS of this family during evolution.

[Characteristics of granular sludge during start-up of the internal circulation]

The quick start-up of the laboratory scale IC reactor and the characteristics of granular sludge during start-up were studied in this paper. The results showed that the first start-up of IC reactor could be finished in 20 days, while secondary start-up only needed 15 days with COD loading rate of 12-15 kg.(m3.d)-1 and COD removal larger than 85%. During start-up, the characteristics of granular sludge changed greatly: average granular diameter was increased from 0.88 mm to 1.25 mm; average settling velocity was enhanced from 35.4 m.h-1 to 105.17 m.h-1; methanogenic activities of the granular increased up to 4 times as large as the seeded sludge; the main methanobacteria was changed from Methanothrix to Methanococcus and Methanobacterium.

Identification of a new human CYP2A gene fragment with close linkage to CYP2GP1

Human genomic libraries were screened to identify CYP2G-related cytochrome P450 genes. A genomic fragment comprising exons 7 through 9 of CYP2GP1 and exons 6 through 9 of a previously unidentified CYP2A gene, designated CYP2A7P2, was isolated from an EMBL3 library; the two genes were arranged in outward opposite directions with about 8 kbp of intervening sequence. The same structure was also detected in a bacteriophage P1 clone, which contained a full-length CYP2GP1 gene, exons 6 through 9 of CYP2A7P2, and the CYP2B7 gene. However, additional CYP2A-related exons as well as other CYP2A genes, CYP2A7P1, CYP2B6, CYP2F1, and CYP2GP2 were not detected. These results indicate that CYP2A7P2 is located near CYP2B7 in the middle of the CYP2A-2B-2F gene cluster on chromosome 19. Furthermore, an analysis of CYP2A sequence alignment suggests that CYP2A7P2 may be derived from the same ancestral gene that gave rise to CYP2A7P1, which was corrupted by a large insertion at intron 5.

A simple copper(II)-L-histidine system for efficient hydrolytic cleavage of DNA

Copper(II)-L-histidine complexes effectively promote the cleavage of plasmid DNA and dideoxynucleotide dApdA at physiological pH and temperature. Studies of the mechanism of plasmid DNA cleavage by added radical scavengers, using rigorously anaerobic experiments, analyses for malondialdehyde-like products, religation assays, and HPLC analyses, indicate that DNA cleavage mediated by Cu(L-His) occurs via a hydrolytic path. The hydrolytic cleavage rate constants at 37 degrees C are estimated to be 0.76 h-1 for the decrease of form I and 0.25 h-1 for the increase of form III. The phosphoimager picture reveals that Cu(L-His) cleaves DNA with a certain sequence specificity (preferentially at 5'-GT-3'). The dinucleotide hydrolysis shows, with [Cu(L-His)] = 0.8 mM, rate enhancement factors of > 10(8). Interestingly, histidine-metal ion interactions (with Cu(II), Ni(II), Zn(II), etc.) have been used for various applications, e.g., protein purification, cross-linking, and targeting proteins to lipid bilayers. Our findings may provide the basis for developing new applications and new ways to design more effective and useful catalysts for DNA cleavage. Cu(L-His) is one of only a few well-defined metal complexes demonstrated to hydrolytically cleave dideoxynucleotides and DNA.