Association of coffee intake with bone mineral density: a Mendelian randomization study

Background

In observational studies, the relationship between coffee intake and bone mineral density (BMD) is contradictory. However, residual confounding tends to bias the results of these studies. Therefore, we used a two-sample Mendelian randomization (MR) approach to further investigate the potential causal relationship between the two.

Methods

Genetic instrumental variables (IVs) associated with coffee intake were derived from genome-wide association studies (GWAS) of the Food Frequency Questionnaire (FFQ) in 428,860 British individuals and matched using phenotypes in PhenoScanner. Summarized data on BMD were obtained from 537,750 participants, including total body BMD (TB-BMD), TB-BMD in five age brackets ≥60, 45-60, 30-45, 15-30, and 0-15 years, and BMD in four body sites: the lumbar spine, the femoral neck, the heel, and the ultradistal forearm. We used inverse variance weighting (IVW) methods as the primary analytical method for causal inference. In addition, several sensitivity analyses (MR-Egger, Weighted median, MR-PRESSO, Cochran's Q test, and Leave-one-out test) were used to test the robustness of the results.

Results

After Bonferroni correction, Coffee intake has a potential positive correlation with total body BMD (effect estimate [Beta]: 0.198, 95% confidence interval [Cl]: 0.05-0.35, P=0.008). In subgroup analyses, coffee intake was potentially positively associated with TB-BMD (45-60, 30-45 years) (Beta: 0.408, 95% Cl: 0.12-0.69, P=0.005; Beta: 0.486, 95% Cl: 0.12-0.85, P=0.010). In addition, a significant positive correlation with heel BMD was also observed (Beta: 0.173, 95% Cl: 0.08-0.27, P=0.002). The results of the sensitivity analysis were generally consistent.

Conclusion

The results of the present study provide genetic evidence for the idea that coffee intake is beneficial for bone density. Further studies are needed to reveal the biological mechanisms and offer solid support for clinical guidelines on osteoporosis prevention.

Associations of the circulating levels of cytokines with risk of ankylosing spondylitis: a Mendelian randomization study

Background

Observational studies have shown that changes in circulating cytokine/growth factor levels occur throughout the initiation and progression of ankylosing spondylitis (AS), yet whether they are etiologic or downstream effects remains unclear. In this study, we performed a summarized-level bidirectional Mendelian randomization (MR) analysis to shed light on the causal relationship between the two.

Methods

Genetic instrumental-variables (IVs) associated with circulating cytokine/growth factor levels were derived from a genome-wide association study (GWAS) of 8,293 European individuals, whereas summary data for the AS were obtained from a FinnGen GWAS of 166,144 participants. We used the inverse-variance-weighted (IVW) method as the main analysis for causal inference. Furthermore, several sensitivity analyses (MR-Egger, weighted median, MR-PRESSO and Cochran's Q test) were utilized to examine the robustness of the results. Finally, reverse MR analysis was performed to assess reverse causality between AS and circulating cytokine/growth factor levels.

Results

After Bonferroni correction, circulating levels of Cutaneous T-cell attracting (CTACK) and Monocyte specific chemokine 3 (MCP-3) were positively associated with a higher risk of AS (odds ratio [OR]: 1.224, 95% confidence interval [95% Cl]: 1.022 ~ 1.468, P = 0.028; OR: 1.250, 95% Cl: 1.016 ~ 1.539, P = 0.035). In addition, elevated circulating levels of Basic fibroblast growth factor (FGF-basic), Granulocyte colony-stimulating factor (G-CSF) and MCP-3 was considered a consequence of AS disease (β = 0.023, P = 0.017; β = 0.017, P = 0.025; β = 0.053, P = 0.025). The results of the sensitivity analysis were generally consistent.

Conclusion

The present study supplies genetic evidence for the relationship between circulating cytokine levels and AS. Targeted interventions of specific cytokines may help to reduce the risk of AS initiation and progression.

Research on evaluation index method of cloud-network convergence capability

There is no measurable and evaluable index system for cloud-network convergence that provides guidance and reference for the subsequent construction and development of cloud-network convergence. It is a big project to select and evaluate the indexes of cloud-network convergence, which requires suitable index selection and index evaluation schemes. Based on analytic hierarchy process (AHP) and entropy weight method, this paper proposes an improved AHP (i-AHP) index selection scheme and index evaluation scheme leveraging the years of experts' experience, the geometric mean and the least square method. The improved weighted least square method (WLSM) is finally proved to be more stable for index evaluation scheme by adding abnormal data. In addition, the index weight obtained by the index evaluation scheme with WLSM are provided as a reference for the future development of cloud-network convergence. The simulation results show that the proposed scheme is superior to the existing index evaluation scheme and can avoid the weight deviation caused by the disturbance and fluctuation of abnormal data.

Piezoresistivity modeling of soft tissue electrical-mechanical properties: A validation study

In general, the electrical property of soft tissues is sensitive to the force applied to their surface. To further study the relationship between the force and the electrical property of soft tissues, this paper attempts to investigate the effect of static and higher-order stresses on electrical properties. Overall, a practical experimental platform is designed to acquire the force information and the electrical property of soft tissues during a contact procedure, which is featured different compression stimuli, such as constant pressing force, constant pressing speed, and step-force compression, etc. Furthermore, the piezoresistive characteristic is innovatively introduced to model the mechanical-electrical properties of soft tissue. Finite Element Modeling (FEM) is adopted to fit the static piezoresistivity of the soft tissue. Finally, experimental studies were performed to demonstrate the effect of stress on the electrical properties and the feasibility of the proposed piezoresistive model to describe soft tissues' mechanical and electrical properties.

Inhibit ALDH3A2 reduce ovarian cancer cells survival via elevating ferroptosis sensitivity

Ovarian cancer (OC) is a malignant gynecologic tumor with high morbidity and mortality. As a newly discovered mode of programmed cell death, ferroptosis has been involved in various pathological processes of kinds of tumors in recent years. Aldehyde dehydrogenase 3 family member A2 (ALDH3A2) catalyzes the oxidation of long-chain aliphatic aldehydes to fatty acid. ALDH3A2 has been shown to be associated with ferroptosis in acute myeloid leukemia (AML), but the mechanism remains unclear. In this study, we analyzed the TCGA and GTEx databases and showed that high ALDH3A2 expression predicted poor prognosis in ovarian cancer. Further studies found that knockout or overexpression of ALDH3A2 correspondingly increased or attenuated the ferroptosis sensitivity of ovarian cancer cells. And sequencing revealed that ALDH3A2 knockout led to the activation of lipid metabolic, GSH metabolic, phospholipid metabolic, and aldehyde metabolic pathways, suggesting that ALDH3A2 induced changes in the sensitivity of ovarian cancer cells to ferroptosis by affecting these metabolic processes. Our results provide a new promising therapeutic strategy for the treatment of OC.

UQCRFS1 serves as a prognostic biomarker and promotes the progression of ovarian cancer

UQCRFS1 has been reported to be highly expressed in gastric and breast cancer, but the mechanism remains unclear. The prognosis and biological functions of UQCRFS1 in ovarian cancer (OC) have not been evaluated. The expression of UQCRFS1 in EOC was detected by GEPIA and HPA websites, and the prognosis value was investigated by Kaplan-Meier analysis. Then the correlation between the UQCRFS1 gene and tumor-related signature were analyzed by Spearman correlation analysis and rank sum test. Subsequently, the expression of the UQCRFS1 gene in four ovarian cancer cell lines was detected. A2780 and OVCAR8 with the highest expression of UQCRFS1 were selected in the following biological experiments. Cell proliferation was detected by CCK8 assay, cell cycle and apoptosis were determined by flow cytometry, reactive oxygen species (ROS) production was detected by DCFH-DA, DNA damage gene mRNA expression was analyzed by RT-PCR, and AKT/mTOR pathway protein expression were also examined by western blot after siRNA transfection. We found that UQCRFS1 was high-expression in EOC and associated with poor prognosis. Spearman correlation analysis revealed that the high expression of UQCRFS1 is associated with the cell cycle, apoptosis, oxidative phosphorylation, and DNA damage. Further studies found that knockdown of UQCRFS1 cells reduced cell proliferation, cell cycle arrest at the G1 phase, increased proportion of apoptosis, ROS production, and expression of DNA damage genes, inhibited ATK/mTOR pathway. The study suggested that UQCRFS1 may be a candidated target for diagnosis and treatments in OC.

Bepotastine sensitizes ovarian cancer to PARP inhibitors through suppressing NF-κB-triggered SASP in cancer-associated fibroblasts

Therapy-induced senescence (TIS) is common in tumor cells treated with poly (ADP-ribose) polymerase inhibitors (PARPis), and can serve as a promising target for improving PARPi efficacy. However, whether stromal components within the tumor microenvironment undergo TIS caused by PARPi and contribute to consequential treatment failure remain unclear. We previously revealed that PARPi triggered a senescence-like secretory phenotype in stromal fibroblasts. Here, we further explored PARPi-induced senescence in the stroma, its contribution to PARPi resistance, and opportunities to leverage stromal TIS for improved PARPi sensitivity. In this study, we demonstrated that tumor tissues from patients treated with neoadjuvant PARPi showed a significant senescence-like phenotype in the stroma. Moreover, PARPi-induced senescent CAFs displayed a senescence-associated secretory phenotype (SASP) profile that was sufficient to induce tumor resistance to PARPi in both homologous recombination-deficient (HRD) and proficient (HRP) ovarian cancer cells. Using the GLAD4U database, we found that bepotastine, an approved H1-antihistamine, inhibited the SASP of PARPi-primed CAFs at clinical serum concentrations. We further demonstrated that bepotastine attenuated fibroblast-facilitated tumor resistance to PARPi in 3D organotypic cultures and HRD-positive PDX models. Mechanistically, bepotastine suppressed PARPi-triggered SASP by inhibiting NF-κB signaling independent of the histamine H1 receptor. Taken together, our results highlight the importance of stromal TIS and SASP in PARPi resistance, and targeting SASP with bepotastine may be a promising therapeutic option for improving PARPi sensitivity in ovarian cancer.

Adipocytes-derived exosomal miR-122 promotes non-alcoholic fat liver disease progression via targeting Sirt1

AIMS

Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease that affects adipose function. This study aimed to explore the function of adipocytes-derived exosomal (ADEs) miR-122 in NAFLD.

METHODS

A high-fat and high-fructose diet-induced rat model and a palmitic acid (PA)-induced in vitro model were established. The RNA level of miR-122 and Sirt1 was measured using qRT-PCR. The protein levels of exosome biomarkers, and lipogenesis, inflammation and fibrosis biomarkers were determined by western blotting. Cell viability and apoptosis were assessed using cell counting kit-8 and flow cytometry, respectively. Serum alanine aminotransferase, aspartate aminotransferase, total cholesterol, triglyceride levels were measured. Liver tissue damage was assessed using haematoxylin and eosin staining. The interaction between miR-122 and Sirt1 3'UTR was assessed using a luciferase reporter gene assay.

RESULTS

ADEs exhibited abundant level of miR-122 and promoted lipogenesis, impaired hepatocyte survival, enhanced liver damage and increased serum lipid levels in vivo and in vitro. Inhibition of miR-122 in ADEs alleviated NAFLD progression, lipid and glucose metabolism, liver inflammation and fibrosis both in vivo and in vitro. miR-122 binds directly to the 3'UTR of Sirt1 to suppress its expression. Moreover, Sirt1 overexpression reversed the increase in cell apoptosis, glucose and lipid metabolism, liver inflammation and fibrosis induced by ADEs in vivo and in vitro.

CONCLUSIONS

The ADEs miR-122 promotes the progression of NAFLD via modulating Sirt1 signalling in vivo and in vitro. The ADEs miR-122 may be a promising diagnostic biomarker and therapeutic target for NAFLD.

6-O-desulfated heparin attenuates myocardial ischemia/reperfusion injury in mice through the regulation of miR-199a-5p/klotho axis

Heparin has been documented to reduce myocardial injury caused by ischemia/reperfusion (I/R), but its clinical application is limited due to its strong intrinsic anticoagulant property. Some desulfated derivatives of heparin display low anticoagulant activity and may have potential value as therapeutic agents for myocardial I/R injury. In this study, we observed that 6-O-desulfated heparin, a desulfated derivative of heparin, shortened the activated partial thromboplastin time and exhibited lower anticoagulant activity compared with heparin or 2-O-desulfated heparin (another desulfated derivative of heparin). Then, we explored whether 6-O-desulfated heparin could protect against myocardial I/R injury, and elucidated its possible mechanisms. Administration of 6-O-desulfated heparin significantly reduced creatine kinase activity, myocardial infarct size and cell apoptosis in mice subjected to 30 min of myocardial ischemia following 2 h of reperfusion, accompanied by a reverse in miR-199a-5p elevation, klotho downregulation and reactive oxygen species (ROS) accumulation. In cultured H9c2 cells, the mechanism of 6-O-desulfated heparin against myocardial I/R injury was further explored. Consistent with the results in vivo, 6-O-desulfated heparin significantly ameliorated hypoxia/reoxygenation-induced injury, upregulated klotho and decreased miR-199a-5p levels and ROS accumulation, and these effects were reversed by miR-199a-5p mimics. In conclusion, these results suggested that 6-O-desulfated heparin with lower anticoagulant activity attenuated myocardial I/R injury through miR-199a-5p/klotho and ROS signaling. Our study may also indicate that 6-O-desulfated heparin, as an excellent heparin derivative, is a potential therapeutic agent for myocardial I/R injury.

[Marsili syndrome manifested by fever: a case report and literature review]

Objective: To describe the clinical features, genetic characteristics, and diagnosis of Marsili syndrome, an extremely rare disease which should be differentiated from other fever disorders. Methods: The clinical data and diagnostic process of a case with Marsili syndrome, hospitalized in the Department of Respiratory and Critical Care Medicine, the Eighth Medical Center of Chinese PLA General Hospital in February 2021, were summarized. The exon regions of 20, 000 genes of peripheral blood were detected in the patient and her parents. Using key words of"Marsili syndrome"and"ZFHX2 gene mutation", the related literatures were searched in Wanfang and PubMed databases from January, 2000 to November, 2021. In addition, the literatures of congenital insensitivity to pain and anhidrosis were retrieved in Wanfang domestic database from the same period. Results: A 23-year-old female patient had suffered from recurrent fever for more than two years, accompanied by anhidrosis, insensitive to pain and weakened corneal reflex. The effect of non-steroidal anti-inflammatory drugs for fever was minimal. The ZFHX2 gene mutation was positive in the patient and her mother, while NTRK1 gene mutation specific to congenital insensitivity to pain with anhidrosis (CIPA) was negative. The ZFHX2 gene mutation was negative in her father. A total of 2 literatures of Marsili syndrome were retrieved and a total of 6 cases of Marsili syndrome in one family were reported worldwide up to now. These patients had a group of similar symptoms including fever, little or no sweating, and insensitivity to pain caused by skin burn and bone fracture. However, there was no abnormality in headache and visceral pain, and female patients' childbirth pain as well as tactile sensation in these cases. The corneal reflex was decreased or negative. They had less sensitivity to stimulus of capsaicin. The ZFHX2 gene mutation was positive, but NTRK1 gene was not detected in all patients. A total of 4 literatures were retrieved and a total of 34 cases of CIPA were reported in China. Though Marsili syndrome and CIPA exhibited a number of similar clinical manifestations, they were distinct diseases and had obviously different outcome. Conclusions: Marsili syndrome is an autosomal dominant genetic disease. It is extremely rare worldwide. In clinical practice, when a patient presents with unexplained recurrent fever and poor effect of non-steroidal anti-inflammatory drugs, especially with the symptoms of no sweating and insensitivity to pain, the possibility of Marsili syndrome should be considered and the ZFHX2 gene should be determined. Marsili syndrome appears to be a benign disease with a good prognosis. A definitive diagnosis can avoid ineffective treatment and its adverse effects. To our knowledge, there is currently no effective genetic therapy for this disease.

A Novel and Fast Encryption System Based on Improved Josephus Scrambling and Chaotic Mapping

To address the shortcomings of weak confusion and high time complexity of the existing permutation algorithms, including the traditional Josephus ring permutation (TJRP), an improved Josephus ring-based permutation (IJRBP) algorithm is developed. The proposed IJRBP replaces the remove operation used in TJRP with the position exchange operation and employs random permutation steps instead of fixed steps, which can offer a better scrambling effect and a higher permutation efficiency, compared with various scrambling methods. Then, a new encryption algorithm based on the IJRBP and chaotic system is developed. In our scheme, the plaintext feature parameter, which is related to the plaintext and a random sequence generated by a chaotic system, is used as the shift step of the circular shift operation to generate the diffusion matrix, which means that a minor change in the source image will generate a totally different encrypted image. Such a strategy strikes a balance between plaintext sensitivity and ciphertext sensitivity to obtain the ability to resist chosen-plaintext attacks (CPAs) and the high robustness of resisting noise attacks and data loss. Simulation results demonstrate that the proposed image cryptosystem has the advantages of great encryption efficiency and the ability to resist various common attacks.

PRCTC: a machine learning model for prediction of response to corticosteroid therapy in COVID-19 patients

Corticosteroid has been proved to be one of the few effective treatments for COVID-19 patients. However, not all the patients were suitable for corticosteroid therapy. In this study, we aimed to propose a machine learning model to forecast the response to corticosteroid therapy in COVID-19 patients. We retrospectively collected the clinical data about 666 COVID-19 patients receiving corticosteroid therapy between January 27, 2020, and March 30, 2020, from two hospitals in China. The response to corticosteroid therapy was evaluated by hospitalization time, oxygen supply duration, and the outcomes of patients. Least Absolute Shrinkage and Selection Operator (LASSO) was applied for feature selection. Five prediction models were applied in the training cohort and assessed in an internal and an external validation dataset, respectively. Finally, two (C reactive protein, lymphocyte percent) of 36 candidate immune/inflammatory features were finally used for model development. All five models displayed promising predictive performance. Notably, the ensemble model, PRCTC (prediction of response to corticosteroid therapy in COVID-19 patients), derived from three prediction models including Gradient Boosted Decision Tree (GBDT), Neural Network (NN), and logistic regression (LR), achieved the best performance with an area under the curve (AUC) of 0.810 (95% confidence interval [CI] 0.760-0.861) in internal validation cohort and 0.845 (95% CI 0.779-0.911) in external validation cohort to predict patients' response to corticosteroid therapy. In conclusion, PRCTC proposed with universality and scalability is hopeful to provide tangible and prompt clinical decision support in management of COVID-19 patients and potentially extends to other medication predictions.

Combined large cell neuroendocrine carcinoma of the lung associated with low-grade fetal adenocarcinoma without β-catenin mutation: a case report

We report a case of combined large cell neuroendocrine carcinoma of the lung associated with low-grade fetal adenocarcinoma (L-FLAC) without β-catenin mutation in exon 3. A 33-year-old man presented at the hospital with a more than 5-month history of cough with no obvious cause. Computed tomography revealed a large, solid, round mass located in the upper lobe of the right lung. Microscopic examination showed two tumor components: large cell neuroendocrine carcinoma and low-grade fetal adenocarcinoma. Immunohistochemistry ofthe fetal adenocarcinoma showed abnormal nuclear/cytoplasmic expression of β-catenin, but no exon 3 mutation in β-catenin. Our findings provide further insight into the pathologic mechanism of FLAC.

Smart handheld device with flexible wrist and electrical bioimpedance sensor for tissue inspection

With the evolving demands of surgical intervention, there is a strong need for smaller and functionally augmented instruments to improve surgical outcomes, operational convenience, and diagnostic safety. Owing to the narrow and complicated anatomy, the probe head of the medical instrument is required to possess both good maneuverability and compact size. In addition, the development of medical instrument is moving toward patient-specialized, of which the articulation positions can be customized to reach the target position. To fulfill these requirements, this study presents the design of a smart handheld device which equips with a low cost, easy control, disposable flexible wrist, and an electrical bioimpedance sensor for medical diagnosis. Prototype of the device is made and tested. The experimental results demonstrate that the proposed device can provide accurate manipulation and effective tissue detection, showing a great potential in various medical applications.

Design and ARM-Based Implementation of Bitstream-Oriented Chaotic Encryption Scheme for H.264/AVC Video

In actual application scenarios of the real-time video confidential communication, encrypted videos must meet three performance indicators: security, real-time, and format compatibility. To satisfy these requirements, an improved bitstream-oriented encryption (BOE) method based chaotic encryption for H.264/AVC video is proposed. Meanwhile, an ARM-embedded remote real-time video confidential communication system is built for experimental verification in this paper. Firstly, a 4-D self-synchronous chaotic stream cipher algorithm with cosine anti-controllers (4-D SCSCA-CAC) is designed to enhance the security. The algorithm solves the security loopholes of existing self-synchronous chaotic stream cipher algorithms applied to the actual video confidential communication, which can effectively resist the combinational effect of the chosen-ciphertext attack and the divide-and-conquer attack. Secondly, syntax elements of the H.264 bitstream are analyzed in real-time. Motion vector difference (MVD) coefficients and direct-current (DC) components in Residual syntax element are extracted through the Exponential-Golomb decoding operation and entropy decoding operation based on the context-based adaptive variable length coding (CAVLC) mode, respectively. Thirdly, the DC components and MVD coefficients are encrypted by the 4-D SCSCA-CAC, and the encrypted syntax elements are re-encoded to replace the syntax elements of the original H.264 bitstream, keeping the format compatibility. Besides, hardware codecs and multi-core multi-threading technology are employed to improve the real-time performance of the hardware system. Finally, experimental results show that the proposed scheme, with the advantage of high efficiency and flexibility, can fulfill the requirement of security, real-time, and format compatibility simultaneously.

Network pharmacology-based analysis of the anti-hyperglycemic active ingredients of roselle and experimental validation

Diabetes mellitus is one of the top four leading causes of death among noncommunicable diseases worldwide, according to the World Hibiscus sabdariffa 2019. Roselle (Hibiscus sabdariffa L.), a traditional herbal medicine, has shown significant clinical anti-hyperglycemic efficacy. However, the mechanism of the treatment is not yet clear. We found that Roselle has a certain protective effect on vascular endothelial cells through this study. This study was based on network pharmacology and experimental validation. The present study made a comprehensive analysis by combining active ingredient screening, target prediction and signaling pathway analysis to elucidate the active ingredients and possible molecular mechanism of roselle for the first time, which provided theoretical and experimental basis for the development and application of roselle as an antidiabetic drug.

Preoperative Prediction of Lymphovascular Space Invasion in Cervical Cancer With Radiomics -Based Nomogram

Purpose

To build and evaluate a radiomics-based nomogram that improves the predictive performance of the LVSI in cervical cancer non-invasively before the operation.

Method

This study involved 149 patients who underwent surgery with cervical cancer from February 2017 to October 2019. Radiomics features were extracted from T2 weighted imaging (T2WI). The radiomic features were selected by logistic regression with the least absolute shrinkage and selection operator (LASSO) penalty in the training cohort. Based on the selected features, support vector machine (SVM) algorithm was used to build the radiomics signature on the training cohort. Incorporating radiomics signature and clinical risk factors, the radiomics-based nomogram was developed. The sensitivity, specificity, accuracy, and area under the curve (AUC) and Receiver operating characteristic (ROC) curve were calculated to assess these models.

Result

The radiomics model performed much better than the clinical model in both training (AUCs 0.925 vs. 0.786, accuracies 87.5% vs. 70.5%, sensitivities 83.6% vs. 41.7% and specificities 90.9% vs. 94.7%) and testing (AUCs 0.911 vs. 0.706, accuracies 84.0% vs. 71.3%, sensitivities 81.1% vs. 43.4% and specificities 86.4% vs. 95.0%). The combined model based on the radiomics signature and tumor stage, tumor infiltration depth and tumor pathology yielded the best performance (training cohort, AUC = 0.943, accuracies 89.5%, sensitivities 85.4% and specificities 92.9%; testing cohort, AUC = 0.923, accuracies 84.6%, sensitivities 84.0% and specificities 85.1%).

Conclusion

Radiomics-based nomogram was a useful tool for predicting LVSI of cervical cancer. This would aid the selection of the optimal therapeutic strategy and clinical decision-making for individuals.

Prevalence and risk factors of thrombotic events on patients with COVID-19: a systematic review and meta-analysis

BACKGROUND

Coagulation abnormalities in COVID-19 patients accompanied with poor prognosis. This study aimed to determine the prevalence and risk factors of thrombotic events on COVID-19 patients.

METHODS

We systematically reviewed all the studies about thrombotic events on COVID-19 patients in PubMed, Embase, Web of Science, MedRxiv, bioRxiv, from Dec 1, 2019 to July 5, 2020. The weighted mean difference (MD) or odds ratio (OR) or relative risk (RR) with 95 % confidence intervals (CI) for clinical data in COVID-19 patients with or without thrombotic events was calculated.

RESULTS

12 articles contained 1083 patients were included for meta-analysis. The prevalence of thrombosis was 22 % (95 % CI 0.08-0.40) in COVID-19 patients and increased to 43 % (95 % CI 0.29-0.65) after admission to the intensive care unit (ICU). Compared with non-thrombotic patients, thrombotic patients had higher levels of D-dimer (MD = 2.79 μg/ml, 95 % CI 2.27-3.31 μg/ml), lactate dehydrogenase (LDH) (MD = 112.71 U/L, 95 % CI 62.40-163.02 U/L), and white blood cells (WBC) (MD = 1.14 *109/L, 95 % CI 0.47-1.81*109/L) while decreased lymphocytes (MD= -0.20*109/L, 95 % CI -0.38 - -0.02*109/L). Age, platelet counts, and male sex tended to be risks while diabetes tended to be a protection for thrombosis for COVID-19 patients, although no statistical difference was achieved. Finally, patients with thrombosis were at a higher risk of death (OR = 2.39, 95 % CI 1.36-4.20).

CONCLUSIONS

Prevalence of thrombosis in COVID-19 patients was high, especially in ICU, though pharmacologic thromboembolism prophylaxis was applied. Therefore, higher levels of D-dimer, LDH, WBC, and decreased lymphocytes needed to be paid close attention to in patients with COVID-19.

Anlotinib suppresses MLL-rearranged acute myeloid leukemia cell growth by inhibiting SETD1A/AKT-mediated DNA damage response

Leukemias driven by chromosomal translocation of the mixed-lineage leukemia (MLL) gene are highly prevalent in hematological malignancy. The poor survival rate and lack of effective targeted therapy for patients with MLL-rearranged (MLL-r) leukemias emphasize an urgent need for improved knowledge and novel therapeutic approaches for these malignancies. The present study aimed to investigate the potential effectiveness and mechanism of Anlotinib, a novel receptor tyrosine kinase inhibitor, in MLL-r acute myeloid leukemia (AML). The findings revealed that Anlotinib significantly inhibited the growth of MLL-r AML cells in both in vivo and a murine xenograft model. RNA sequencing identified that multiple genes involved in DNA damage response were responsible for Anlotinib activity. To further elucidate the correlation between the DNA damage response induced by Anlotinib and MLL fusion, Gene Expression Profiling Interactive Analysis (GEPIA) was conducted. It revealed that Anlotinib impaired DNA damage response via inhibiting SETD1A and AKT. In conclusion, Anlotinib exerts anti-leukemia function by inhibiting SETD1A/AKT-mediated DNA damage response and highlights a novel mechanism underlying Anlotinib in the treatment of MLL-r AML.

Heterogeneity of immune microenvironment in ovarian cancer and its clinical significance: a retrospective study

Treatment of ovarian cancer (OC) remains the biggest challenge among gynecological malignancies. Immune checkpoint blockade therapy is promising in many cancers but shows low response rates in OC because of its heterogeneity. Although the biological and molecular heterogeneity of OC has been extensively investigated, heterogeneity of immune microenvironment remains elusive. We have collected the expression profiles of 3071 OC patients from 22 publicly available datasets. CIBERSORT was applied to infer the infiltration fraction of 22 immune cells among 2086 patients with CIBERSORT P < .05. We then explored the heterogeneity landscape of immune microenvironment in OC at three levels (immune infiltration, prognostic relevance of immune infiltration, immune checkpoint expression patterns). Multivariable Cox regression model was used to investigate the associations between survival risk and immune infiltration. Constructed immune risk score stratified patients with significantly different survival risk (HR: 1.47, 95% CI: 1.31–1.66, P < .0001). The immune infiltration landscape, prognostic relevance of immune cells, and expression patterns of 79 immune checkpoints exhibited remarkable clinicopathological heterogeneity. For instance, M1 macrophages were significantly associated with better outcomes among patients with high-grade, late-stage, type-II OC (HR: 0.77–0.83), and worse outcomes among patients with type-I OC (HR: 1.78); M2 macrophages were significantly associated with worse outcomes among patients with high-grade, type-II OC (HR: 1.14–1.17); Neutrophils were significantly associated with worse outcomes among patients with high-grade, late-stage, type-I OC (HR: 1.14–1.73). The heterogeneous landscape of immune microenvironment presented in this study provided new insights into prognostic prediction and tailored immunotherapy of OC.

Design of a Drop-in EBI Sensor Probe for Abnormal Tissue Detection in Minimally Invasive Surgery

It is a common challenge for the surgeon to detect pathological tissues and determine the resection margin during a minimally invasive surgery. In this study, we present a drop-in sensor probe based on the electrical bioimpedance spectroscopic technology, which can be grasped by a laparoscopic forceps and controlled by the surgeon to inspect suspicious tissue area conveniently. The probe is designed with an optimized electrode and a suitable shape specifically for Minimally Invasive Surgery (MIS). Subsequently, a series of ex vivo experiments are carried out with porcine liver tissue for feasibility validation. During the experiments, impedance measured at frequencies from 1 kHz to 2 MHz are collected on both normal tissues and water soaked tissue. In addition, classifiers based on discriminant analysis are developed. The result of the experiment indicate that the sensor probe can be used to measure the impedance of the tissue easily and the developed tissue classifier achieved accuracy of 80% and 100% respectively.

[Short-term effectiveness of axis laminar screws for reducible atlantoaxial dislocation]

Objective

To investigate reliability and short-term effectiveness of axis laminar screws for reducible atlantoaxial dislocation (RAAD).

Methods

A clinical data of 41 patients with RAAD who were admitted between February 2013 and February 2018 and met the inclusion criteria was retrospectively analyzed. The atlases in all patients were fixated by lateral mass screws, and the axes were fixed by laminar screws in 13 cases (LS group) and by pedicle screws in 28 cases (PS group). There was no significant difference in gender, age, and preoperative Japanese Orthopedic Association (JOA) score between the two groups ( P>0.05). The effectiveness was estimated by post-operative JOA score; and the accuracy of the axis screw, atlantoaxial bone graft fusion, and the fixation stability were examined by X-ray film and CT.

Results

All incisions healed by first intention. All patients were followed up 12-17 months (mean, 13.8 months) in LS group and 12-20 months (mean 14.1 months) in PS group, and the difference in follow-up time was not significant ( Z=-0.704, P=0.482). At last follow-up, JOA scores were 13.9±1.6 in LS group and 14.3±1.8 in PS group, which significantly improved when compared with the pre-operative scores in the two groups ( t=-9.033, P=0.000; t=-15.835, P=0.000); while no significant difference was found between the two groups ( t=-0.630, P=0.532). Twenty-five screws of 26 screws in LS group and 54 screws of 56 screws in PS group were implanted accurately, with no significant difference in the accuracy of the axis screw between the two groups ( Z=-0.061, P=0.951). All patients obtained atlantoaxial bone graft fusion, except 1 case in PS group. There was no significant difference in the atlantoaxial bone graft fusion between the two groups ( Z=-0.681, P=0.496).

Conclusion

For RAAD, Axis laminar screws can maintain the atlantoaxial primary stability and had a good short-term effectiveness. So, it could be an alternative and reliable technique for axis screw.

A new development of non-local image denoising using fixed-point iteration for non-convex ℓp sparse optimization

We proposed a new efficient image denoising scheme, which mainly leads to four important contributions whose approaches are different from existing ones. The first is to show the equivalence between the group-based sparse representation and the Schatten-p norm minimization problem, so that the sparsity of the coefficients for each group can be measured by estimating the underlying singular values. The second is that we construct the proximal operator for sparse optimization in ℓ_p space with p ∈ (0, 1] by using fixed-point iteration and obtained a new solution of Schatten-p norm minimization problem, which is more rigorous and accurate than current available results. The third is that we analyze the suitable setting of power p for each noise level σ = 20, 30, 50, 60, 75, 100, respectively. We find that the optimal value of p is inversely proportional to the noise level except for high level of noise, where the best values of p are 1 and 0.95, when the noise levels are respectively 75 and 100. Last we measure the structural similarity between two image patches and extends previous deterministic annealing-based solution to sparsity optimization problem through incorporating the idea of dictionary learning. Experimental results demonstrate that for every given noise level, the proposed Spatially Adaptive Fixed Point Iteration (SAFPI) algorithm attains the best denoising performance on the value of Peak Signal-to-Noise Ratio (PSNR) and structure similarity (SSIM), being able to retain the image structure information, which outperforms many state-of-the-art denoising methods such as Block-matching and 3D filtering (BM3D), Weighted Nuclear Norm Minimization (WNNM) and Weighted Schatten p-Norm Minimization (WSNM).

A Simple Chaotic Map-Based Image Encryption System Using Both Plaintext Related Permutation and Diffusion

Recently, to conquer most non-plain related chaos-based image cryptosystems' security flaws that cannot resist the powerful chosen/knownn plain-text attacks or differential attacks efficiently for less plaintext sensitivity, many plain related chaos-based image cryptosystems have been developed. Most cryptosystems that have adopted the traditional permutation-diffusion structure still have some drawbacks and security flaws: (1) most plaintext related image encryption schemes using only plaintext related confusion operation or only plaintext related diffusion operation relate to plaintext inadequately that cannot achieve high plaintext sensitivity; (2) in some algorithms, the generation of security key that needs to be sent to the receiver is determined by the original image, so these algorithms may not applicable to real-time image encryption; (3) most plaintext related image encryption schemes have less efficiency because more than one round permutation-diffusion operation is required to achieve high security. To obtain high security and efficiency, a simple chaotic based color image encryption system by using both plaintext related permutation and diffusion is presented in this paper. In our cryptosystem, the values of the parameters of cat map used in permutation stage are related to plain image and the parameters of cat map are also influenced by the diffusion operation. Thus, both the permutation stage and diffusion stage are related to plain images, which can obtain high key sensitivity and plaintext sensitivity to resist chosen/known plaintext attacks or differential attacks efficiently. Furthermore, only one round of plaintext related permutation and diffusion operation is performed to process the original image to obtain cipher image. Thus, the proposed scheme has high efficiency. Complete simulations are given and the simulation results prove the excellent security and efficiency of the proposed scheme.

Growth of hierarchical TiO2 flower-like microspheres/oriented nanosheet arrays on a titanium mesh for flexible dye-sensitized solar cells

A triple-layer TiO₂ (TiO₂-TL) structure was synthesized with an over-layer composed of TiO₂ flower-like microspheres (MSs), a middle layer of nanosheet arrays (NSAs) and an under-layer of compact film (CF) on a titanium (Ti) mesh substrate using a one-step hydrothermal route and used to make a series of flexible dye-sensitized solar cells (DSSCs).

LOX-1 mediated phenotypic switching of pulmonary arterial smooth muscle cells contributes to hypoxic pulmonary hypertension

In pulmonary hypertension (PH), pulmonary arterial smooth muscle cells (PASMCs) are dedifferentiated, undergoing a contractile-to-synthetic phenotypic switching. Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) plays diverse roles in the cardiovascular system, but its contribution to PH remains to be fully defined. The present study was undertaken to explore the role of LOX-1 in PASMCs dedifferentiation in hypoxia-induced pulmonary vascular remodeling and PH. In a rat model of hypoxic PH, pulmonary vascular remodeling was accompanied by increased expression of LOX-1 in pulmonary arteries. In primary rat PASMCs, hypoxia-induced PASMCs dedifferentiation occurred concomitantly with LOX-1 upregulation. Inhibition of LOX-1 by either siRNA knockdown or neutralizing antibody significantly ameliorated PASMCs dedifferentiation. Mechanistically, LOX-1 promotes PASMCs dedifferentiation under hypoxic conditions via ERK1/2-Elk-1/MRTF-A/SRF signaling pathway. In conclusion, our data uncovers an important role of LOX-1 in the maintenance of PASMCs phenotype. Therapeutic targeting of LOX-1/ERK1/2-Elk-1/MRTF-A/SRF signaling axis would be exploited to treat hypoxic PH.

[Effectiveness comparison between unilateral and bilateral percutaneous kyphoplasty for Kümmell disease]

Objective

To compare the effectiveness between unilateral and bilateral percutaneous kyphoplasty (PKP) in the treatment of Kümmell disease.

Methods

The clinical data of 45 patients with Kümmell disease that met the criteria between January 2014 and February 2016 were analyzed retrospectively. Among them, 26 cases were treated by unilateral PKP (unilateral group), 19 cases were treated by bilateral PKP (bilateral group). There was no significant difference in gender, age, disease duration, injured vertebral segment, bone mineral density (T value), and the preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI), anterior vertebral height, and kyphosis Cobb angle between 2 groups ( P>0.05). The operation time, intraoperative fluoroscopy times, amount of injected bone cement, and hospitalization time were recorded, and the situation of bone cement leakage was observed. The VAS score, ODI, anterior vertebral height, and kyphosis Cobb angle were evaluated before operation, at 1 day after operation, and at last follow-up.

Results

Bone cement leakage during the operation were found in 4 cases (15.38%) of unilateral group and 3 cases (15.79%) of bilateral group without obvious neurological symptoms; there was no significant difference in the incidence of bone cement leakage between 2 groups ( χ²=0.000, P=1.000). The operation time, intraoperative fluoroscopy times, and amount of injected bone cement in the unilateral group were significantly lower than those in the bilateral group ( P<0.05); but there was no significant difference in the hospitalization time between 2 groups ( P>0.05). The X-ray film examination showed that there was no pulmonary embolism in all patients at 1 day after operation. All the patients were followed up 12-24 months, with an average of 16.4 months. There was no complication such as vertebral re-fracture or cement block displacement in the injured vertebra. The VAS score, ODI, anterior vertebral height, and kyphosis Cobb angle at 1 day after operation and at last follow-up were significantly improved when compared with preoperative values in 2 groups ( P<0.05); the VAS score and ODI in 2 groups were further reduced at last follow-up when compared with the value at 1 day after operation ( P<0.05), but the anterior vertebral height and kyphosis Cobb angle in 2 groups at last follow-up did not change significantly ( P>0.05). There was no significant difference in above indexes at 1 day after operation and at last follow-up between 2 groups ( P>0.05).

Conclusion

Both unilateral and bilateral PKP can achieve good effectiveness in treatment of Kümmell disease. But the unilateral puncture technique possesses advantages such as shorter operation time, less radiation dose, and less amount of injected bone cement.

Resveratrol derivative BTM-0512 mitigates obesity by promoting beige remodeling of subcutaneous preadipocytes

Recent studies revealed that sirtuin 1 (SIRT1) is involved in the regulation of energy metabolism and its agonist resveratrol showed anti-obesity effect. This study aims to determine whether BTM-0512, a novel derivative of resveratrol, acts as an antagonist of obesity and to explore its possible mechanisms. High-fat diet (HFD)-induced obese mice were intragastrically administered with BTM-0512 (5, 10, and 20 mg/kg/day) or resveratrol (10 mg/kg/day). It was found that the body weight, Lee's index, ratio of visceral adipose tissue (VAT) to body weight, and blood glucose were significantly reduced in BTM-0512-treated mice when compared with those in mice treated with resveratrol. BTM-0512 up-regulated the expressions of SIRT1, full length PRDM16 (fPRDM16), total PRDM16 (tPRDM16, including fPPRDM16 and other PRDM16 isoforms), and uncoupling protein 1 (UCP1) in both brown and subcutaneous adipose tissues. Although BTM-0512 and resveratrol also up-regulated SIRT1 and tPRDM16 levels in VAT of HFD-induced obese mice, the expressions of fPRDM16, UCP1, and TMEM26 were down-regulated. In mouse primary subcutaneous preadipocytes cultured with or without adipogenic medium, BTM-0512 up-regulated fPRDM16, tPRDM16, and UCP1 expressions, which was reversed by SIRT1 antagonists. But in cultured brown and visceral adipocytes, the UCP1 protein level showed no significant change after treatment with 1 μM of BTM-0512. Moreover, transfection with human SIRT1 plasmid reduced lipid deposit, as well as the mRNA levels of fPRDM16, UCP1, and TMEM26, in cultured human visceral adipose-derived stem cells. In conclusion, BTM-0512 has stronger anti-obesity effect than resveratrol, which might be associated with activation of beige remodeling in subcutaneous adipose tissue.

LC-UV Determination of Baicalin in Rabbit Plasma and Tissues for Application in Pharmacokinetics and Tissue Distribution Studies of Baicalin after Intravenous Administration of Liposomal and Injectable Formulations

A simple and sensitive LC-UV method to investigate the pharmacokinetics and biodistribution pattern of baicalin in rabbits was established and validated. Baicalin and the internal standard, rutin, were extracted from biosamples using acetonitrile as protein precipitation after pretreated with ammonium acetate buffer (pH 3.5; 1 M) to obtain a pure chromatographic peak and high extraction recovery. Chromatographic separation was achieved on a reverse-phase C18 column with a gradient elution at flow rate of 1.0 mL/min. UV absorption was set at 278 nm. Chromatographic response was linear over the ranges of 0.05–10.00 μg/mL in plasma and 0.05–300.00 μg/g in tissues with the limits of quantification of 50.0 ng/mL in plasma and tissues, and the limit of detection of baicalin in bio-samples of 15 ng/mL. The RSD of intra-and inter-day for the biosamples were from 4.19% to 10.84% and from 4.37% to 10.93%, respectively. The accuracy of plasma and tissue samples ranged from 81.6% to 95.2% and 80.8% to 98.4%, respectively. The extraction recoveries ranged from 81.5% to 88.3% for plasma, from 73.1% to 93.2% for tissues, respectively. Baicalin was stable in rabbit biosamples. The validated method was successfully applied to the study of the pharmacokinetics and tissue distribution of baicalin after intravenous administration of liposomal and injectable formulations to rabbits. Compared to baicalin injection, the pharmacokinetics and biodistribution behavior of baicalin was altered significantly in rabbits treated with its liposomes and drug concentration in the lungs was greatly increased.

Amplitude dependence of elasticity for the assembly of SiO2 powders under shear oscillation strain

We experimentally report the elastic response of an assembly of SiO2 powders under a shear oscillation strain by a modified inverted torsion pendulum with a Couette-like setup. We find that the shear restoring force displayed by SiO2 assembly is of strong amplitude dependence, which is ascribed to the dynamic behavior of the stress network inside and could be used to classify the states of the SiO2 assembly, i.e., elastic solid, plastic solid, viscoelastic solid, and viscous fluid. The underlying mechanisms for different states of the SiO2 assembly are tentatively proposed.

Universal and scaling behavior at the proximity of the solid to the deformable air-water interface

The scaling descriptions of the deformation of the air-water interface due to van der Waals attractive forces induced by a paraboloid shaped solid as well as of the force vs distance behavior are systematically discussed theoretically and experimentally. It is demonstrated that the force-distance curves at the proximity of the solid to the air-water interface without contact satisfy a simple and universal scaling law, which can be useful to help study various systems involved in the deformable interface. Moreover, an analytical solution to the E-L differential equation governing the deformation of the water surface profile is obtained from the scaling relation, and the two length scales that quantitatively evaluate the lateral and longitudinal deformation of the air-water interface respectively are hence determined.

Comparative analysis of internal friction and natural frequency measured by free decay and forced vibration

Relations between various values of the internal friction (tgdelta, Q(-1), Q(-1*), and Lambda/pi) measured by free decay and forced vibration are analyzed systemically based on a fundamental mechanical model in this paper. Additionally, relations between various natural frequencies, such as vibration frequency of free decay omega(FD), displacement-resonant frequency of forced vibration omega(d), and velocity-resonant frequency of forced vibration omega(0) are calculated. Moreover, measurement of natural frequencies of a copper specimen of 99.9% purity has been made to demonstrate the relation between the measured natural frequencies of the system by forced vibration and free decay. These results are of importance for not only more accurate measurement of the elastic modulus of materials but also the data conversion between different internal friction measurements.

Protective effects of cariporide on endothelial dysfunction induced by high glucose

AIM

To explore the effects of cariporide, a selective sodium-hydrogen antiporter inhibitor, on endothelial dysfunction induced by high glucose.

METHODS

Acetylcholine (ACh)-induced endothelium-dependent relaxation (EDR), sodium nitroprusside (SNP)-induced endothelium-independent relaxation and biochemical parameters including malondialdehyde (MDA), superoxide dismutase (SOD), and nitric oxide (NO) were measured in rat isolated aorta.

RESULTS

A 6-h incubation of aortic rings with high glucose (44 mmol/L) resulted in a significant inhibition of EDR, but had no effects on endothelium-independent relaxation. After the 6-h incubation of aortic rings in the co-presence of cariporide (0.01, 0.1, and 1 micromol/L) with high glucose, cariporide prevented the inhibition of EDR caused by high glucose in concentration-dependent manners. Similarly, high glucose decreased SOD activity and contents of NO, and increased MDA concentration in aortic tissue. Cariporide (1 micromol/L) significantly resisted the decrease of NO content and SOD activity, and elevation of MDA concentration caused by high glucose in aortic tissues. Mannitol (44 mmol/L) or cariporide (1 micromol/L) alone had no effect on EDR, endothelium-independent relaxation and biochemical parameters.

CONCLUSION

Cariporide significantly prevented endothelial dysfunction induced by high glucose. The mechanisms of endothelial dysfunction induced by high glucose may involve the activation of sodium-hydrogen antiporter and the generation of oxygen-free radicals, but it is not related to the change of osmolarity.

[Protective effects of shenmai injection on DPPH free radical-induced injuries in isolated hearts in rabbits]

OBJECTIVE

To examine the protective effects of shenmai injection (SM) on DPPH free radical-induced myocardial injury in isolated hearts in rabbits.

METHODS

The isolated rabbit hearts were perfused in a Langendorff model. The left ventricular pressure (LVP), the first derivative of LVP (+dp/dtmax), left ventricular end-diastolic pressure (LVEDP) and heart rate(HR) were recorded. Coronary flow (CF) and creatine Kinase (CK) of coronary issue were measured.

RESULTS

Perfusion with DPPH (0.25 mumol/L) for 5 min caused a significant impairment of cardiac function, as shown by a decrease in LVP and +dp/dtmax and an increase in LVEDP as well as the increased release of CK. Pretreatment with shenmai injection (1:320) for 10 min significantly improved the cardiac function and decreased the release of CK.

CONCLUSION

Shenmai injection protects against the myocardial injury induced by free radical (DPPH) in isolated rabbit hearts.

Protective effects of calcitonin gene-related peptide on guinea-pig cardiac anaphylaxis

Anaphylactic events occurring in cardiac tissues can result in cardiac dysfunction via vasoconstriction and arrhythmias. Calcitonin gene-related peptide (CGRP) is the most potent vasodilator and possesses anti-arrhythmic action. We examined the influence of CGRP on cardiac anaphylaxis in guinea-pigs. In the Langendorff-perfused heart of passively sensitized guinea-pigs, antigen challenge evoked a decrease in coronary flow, left ventricular pressure and its maximum first derivatives (+/-dP/dtmax) and an increased heart rate. Antigen challenge also induced atrioventricular conduction block. Treatment with CGRP (1 or 3 nM) significantly improved the recovery of cardiac function and reduced the incidence and duration of atrioventricular block without influencing the increased heart rate. Pretreatment with capsaicin caused effects similar to those of CGRP and markedly elevated the content of CGRP in coronary effluent. Ischaemic preconditioning, induced by two cycles each of 5 min global ischaemia and 5 min reperfusion, also improved cardiac function and raised the level of CGRP in coronary effluent. The protective effects of ischaemic preconditioning were abolished in the presence of the CGRP receptor antagonist CGRP8-37. Histamine release did not differ significantly during any of the interventions. The findings of the present study indicate that, in guinea-pig hearts, CGRP protects against cardiac anaphylaxis and that the cardioprotection by CGRP is independent of histamine release.

Protective effects of 17 beta-estradiol on endothelial function injured by oxidized low-density lipoproteins

AIM

To test the protective effects of 17 beta-estradiol against endothelial cell damages due to oxidized low-density lipoproteins (LDL) and lysophosphatidylcholine (LPC), a principal component of oxidized LDL.

METHODS

After the tension was increased by phenylephrine, the effects of oxidized LDL or LPC on the vasorelaxation responses to acetylcholine (ACh) were investigated in the isolated rabbit thoracic aortas.

RESULTS

17 beta-Estradiol attenuated the inhibition of vasorelaxation responses to ACh by oxidized LDL or LPC in a concentration-dependent manner. However, the protective effect of 17 beta-estradiol was partially attenuated by indometacin (10 mumol.L-1), a cyclooxygenase inhibitor.

CONCLUSION

17 beta-Estradiol possesses protective effects on the endothelium against injury elicited by oxidized LDL or LPC, which may be related to its stimulation of epoprostenol production.

Influence of endothelium on responses of isolated dog coronary artery to beta-adrenoceptor agonists

AIM

To study the role of the endothelium in mediating the response of the coronary arteries to adrenoceptor agonists.

METHODS

Endothelium intact and denuded dog epicardial coronary artery rings were used. The contractile responses were recorded on forcetransducer and a pen recorder.

RESULTS

In all ring segments, norepinephrine (NE) and isoproterenol (Iso) produced concentration-dependent relaxation in the presence and absence of phentolamine. Endothelium-removal decreased this relaxation and depressed the maximal response. Inhibition of nitric oxide synthesis by N omega-nitro-L-arginine-methyl ester induced the same influences as endothelium-removal.

CONCLUSION

beta-adrenoceptor agonists produce relaxation of dog coronary artery by both endothelium-dependent and independent mechanisms, endothelium-dependent relaxation induced by beta-adrenoceptor agonists is mediated by nitric oxide.