Classification models and SAR analysis on thromboxane A2 synthase inhibitors by machine learning methods

Thromboxane A2 synthase (TXS) is a promising drug target for cardiovascular diseases and cancer. In this work, we conducted a structure-activity relationship (SAR) study on 526 TXS inhibitors for bioactivity prediction. Three types of descriptors (MACCS fingerprints, ECFP4 fingerprints, and MOE descriptors) were utilized to characterize inhibitors, 24 classification models were developed by support vector machine (SVM), random forest (RF), extreme gradient boosting (XGBoost), and deep neural networks (DNN). Then we reduced the number of fingerprints according to the contribution of descriptors to the models, and constructed 16 extra models on simplified fingerprints. In general, Model_4D built by DNN algorithm and 67 bits MACCS fingerprints performs best. The prediction accuracy of the model on the test set is 0.969, and Matthews correlation coefficient (MCC) is 0.936. The distance between compound and model (dSTD-PRO) was used to characterize the application domain of the model. In the test set of Model_4D, dSTD-PRO of 91.5% compounds is lower than the corresponding training set threshold (threshold0.90 = 0.1055), and the accuracy of these compounds is 0.983. In addition, the important descriptors were summarized and further analyzed. It showed that aromatic nitrogenous heterocyclic groups were beneficial to improve the bioactivity of TXS inhibitors.

Probing CP symmetry and weak phases with entangled double-strange baryons

Though immensely successful, the standard model of particle physics does not offer any explanation as to why our Universe contains so much more matter than antimatter. A key to a dynamically generated matter-antimatter asymmetry is the existence of processes that violate the combined charge conjugation and parity (CP) symmetry1. As such, precision tests of CP symmetry may be used to search for physics beyond the standard model. However, hadrons decay through an interplay of strong and weak processes, quantified in terms of relative phases between the amplitudes. Although previous experiments constructed CP observables that depend on both strong and weak phases, we present an approach where sequential two-body decays of entangled multi-strange baryon-antibaryon pairs provide a separation between these phases. Our method, exploiting spin entanglement between the double-strange Ξ- baryon and its antiparticle2 [Formula: see text], has enabled a direct determination of the weak-phase difference, (ξP - ξS) = (1.2 ± 3.4 ± 0.8) × 10-2 rad. Furthermore, three independent CP observables can be constructed from our measured parameters. The precision in the estimated parameters for a given data sample size is several orders of magnitude greater than achieved with previous methods3. Finally, we provide an independent measurement of the recently debated Λ decay parameter αΛ (refs. 4,5). The [Formula: see text] asymmetry is in agreement with and compatible in precision to the most precise previous measurement4.

A retrospective study of factors contributing to anchorage loss in upper premolar extraction cases

Background

Anchorage control is one of the components in the treatment of extraction cases. However, what determines more or less anchorage loss is still an unanswered question. Aim: The purpose of this study was to investigate the most important factors contributing to the anchorage loss of maxillary first molars in premolar extraction cases.

Materials and Methods

The study included 726 upper premolar extraction cases, including 214 male patients and 512 female patients, and the mean age was 14.4 ± 4.5 years old (range: 9-45). Factors including physiological characteristics, treatment mechanics, and cephalometric variables were collected and their influences on the angulation changes of maxillary first molars were analyzed.

Results

The mean angulation change of maxillary first molar after treatment was 2.81°(mesial tipping). The change of UM/PP showed a statistically significant difference in different sex (male 3.84° ± 5.26° vs female 2.38° ± 5.10°), age (adult -0.05° ± 4.73° vs teenager 3.46° ± 5.07°), and molar relationship (Class II 3.28° ± 5.15° vs Class I 2.36° ± 5.19°). There are six variables accounted in the regression analysis (R = 0.608, R² = 37.0%). Among them, the pre-treatment molar tipping (Standardized Coefficients: -0.65) and the pre-treatment incisor/molar height ratio (Standardized Coefficients: -0.27) were the most important factors influencing anchorage loss during treatment.

Conclusion

Compared with treatment-related factors, the patient's physiological characteristics play a more important role in anchorage loss. The pre-treatment angulation of the maxillary first molar is the most influential factor in changes to maxillary molar angulation, which are often predisposing anchorage loss.

Observation of the Singly Cabibbo Suppressed Decay Λ_{c}^{+}→nπ^{+}

The singly Cabibbo-suppressed decay Λ_{c}^{+}→nπ^{+} is observed for the first time with a statistical significance of 7.3σ by using 3.9  fb^{-1} of e^{+}e^{-} collision data collected at center-of-mass energies between 4.612 and 4.699 GeV with the BESIII detector at BEPCII. The branching fraction of Λ_{c}^{+}→nπ^{+} is measured to be (6.6±1.2_{stat}±0.4_{syst})×10^{-4}. By taking the upper limit of branching fractions of Λ_{c}^{+}→pπ^{0} from the Belle experiment, the ratio of branching fractions between Λ_{c}^{+}→nπ^{+} and Λ_{c}^{+}→pπ^{0} is calculated to be larger than 7.2 at the 90% confidence level, which disagrees with most predictions of the available phenomenological models. In addition, the branching fractions of the Cabibbo-favored decays Λ_{c}^{+}→Λπ^{+} and Λ_{c}^{+}→Σ^{0}π^{+} are measured to be (1.31±0.08_{stat}±0.05_{syst})×10^{-2} and (1.22±0.08_{stat}±0.07_{syst})×10^{-2}, respectively, which are consistent with previous results.

[The short-term and long-term prognostic analysis in patients with chronic total occlusion acute non-ST segment elevation myocardial infarction]

Objectives: To investigate the clinical impacts of chronic total occlusion (CTO) in acute non-ST segment elevation myocardial infarction (NSTEMI) patients underwent primary percutaneous coronary intervention (PCI). Methods: A total of 2 271 acute NSTEMI patients underwent primary PCI from China Acute Myocardial Infarction Registry were enrolled in this study and divided into the CTO group and the non-CTO group according to the angiography. The primary endpoint was in-hospital mortality and mortality during a 2-year follow-up. The secondary endpoint was major adverse cardiovascular events (MACE) including revascularization, death, re-myocardial infarction, heart failure readmission, stroke and major bleeding. Results: Thirteen-point four percent of the total acute NSTEMI patients had concurrent CTO. In-hospital mortality (3.6% vs. 1.4%, P<0.01) and 2-year mortality (9.0% vs. 5.1%, P<0.01) were significantly higher in the CTO group than those in the non-CTO group, respectively. Multiple regression analyses showed that chronic obstructive pulmonary disease (HR 7.28, 95%CI 1.50-35.35, P=0.01) was an independent risk factor of in-hospital mortality, and advanced age (HR 1.04, 95%CI 1.01-1.07, P<0.01), and low levels of ejection fraction (HR 0.95, 95%CI 0.93-0.98, P<0.01) were independent risk factors of 2-year mortality. CTO (HR1.67, 95%CI 1.10-2.54, P=0.02) was an independent risk factor of revascularization, but not a risk factor of mortality. Conclusions: Although acute NSTEMI patients concurrent with CTO had higher mortality, CTO was only an independent risk factor of revascularization, but not of mortality. Advanced age and low levels of ejection fraction were independent risk factors of long-term death among acute NSTEMI patients.

[Technical summary and experiences of urinary reconstruction in mouse kidney transplantation]

The present paper summarizes the methods and technical key points for urinary reconstruction in mouse kidney transplantation. Both bladder patch and ureter implantation techniques are feasible options for urinary reconstruction in mouse kidney transplantation. The dominant complication in bladder patch technique is ischemic necrosis of patch and distal ureter and is associated with donor mouse strains and surgical skills. The most common complication in ureter implantation technique is urine leakage and is related to recipient mouse gender and technical skills. The key technical points for bladder patch method are estimation of blood supply for bladder patch and properly trimming and suturing bladder walls. The key points for ureter implantation method are properly trimming and fixation of the ureter. Comparing with the bladder patch, the ureter implantation technique is faster, its complications are easier to be repaired by secondary surgery, but the risk of urine retention is higher at late time. The timeliness of surgical intervention is a key factor for successfully repairing the early urinary complications.

[Combined endoscopic and microsurgical resection of pineal region meningiomas by modified Poppen approach]

To retrospectively analyze the clinical data of patients with pineal region meningioma. All the patients underwent combined endoscopic and microsurgical procedure by modified Poppen approach (double-scopic technique) between January 2018 and March 2021 in the Department of Neurosurgery of the First Affiliated Hospital of Soochow University. A total tumor resection was achieved in all the patients without deaths. All the pineal region meningiomas were pathologically confirmed. During the follow-up period, none of the 10 patients experienced tumor progression, and 4 of patients were treated by radiotherapy after surgery. The external ventricular drainage was performed in 8 cases intraoperatively, and no case underwent the ventriculoperitoneal shunt during the follow-up period. The clinical symptoms of 9 cases were improved,1 case had no improvement, and no patients presented deteriorated symptoms. Combined endoscopic and microsurgical surgery resection of pineal region meningiomas by modified Poppen approach helped the surgeons directly observe the cerebral deep vein systems in pineal region with endoscope and significantly enhance the total resection rate of pineal region meningiomas, thereby decreasing the damage of cerebral deep vein systems in pineal region and reducing the incidence of surgical complications.

[A cohort study of association between sleep duration and cognitive impairment in the elderly aged 65 years and older in China]

Objective: To explore the effect of sleep duration on the risk of cognitive impairment in the elderly in China. Methods: Baseline data of 9 679 elderly individuals with intact cognition were collected from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) in 2005, and followed up was conducted until 2018. Cox proportional hazards model was used to analyze the association between different sleep durations and the risk for cognitive impairment in the elderly. Results: Compared with elderly with sleep duration of 6 hours per day, those with sleep duration less than 5 hours had increased risk for cognitive impairment by 30% (HR=1.30, 95%CI: 1.05-1.62), and those with sleep durations of 7 hours, 8 hours and more than 9 hours had increased risk for cognitive impairment by 34% (HR=1.34,95%CI: 1.09-1.64), 40% (HR=1.40,95%CI: 1.17-1.69) and 43% (HR=1.43,95%CI: 1.19-1.70), respectively. Trend test showed that the risk of cognitive impairment increased with the extension of sleep duration (>6 h), and there was a dose-response relationship (P<0.001). However, self-rated sleep quality was not associated with the risk for cognitive impairment in the elderly. Conclusions: The shorter and longer sleep duration were associated an increased risk of cognitive impairment in the elderly aged ≥65 years in China, suggesting that optimizing sleep duration might delay the occurrence of cognitive impairment.

[The 493th case: recurrent edema of bilateral lower extremeties]

A 43-year-old male patient with onset of edema caused by nephrotic proteinuria and low titer of anti-M type phospholipase-A₂-receptor (PLA₂R) antibody was diagnosed as idiopathic membranous nephropathy by renal biopsy. Administrated with prednisone 40 mg once a day and cyclosporine 100 mg twice a day as front-line regimen, the patient relapsed after transient partial remission. When treatment was combined with cyclophosphamide 100 mg once a day, the 24-hour total urine protein and titer of anti-PLA₂R antibody were even elevated. Therefore, the patient received rituximab 1 g intravenously in April 2019, October 2019 and October 2020 respectively. CD19 positive B lymphocytes in peripheral blood were eliminated from 71/μl to zero. Immunosuppressants and corticosteroids were withdrawn successively. On the last follow-up in November 2020, the anti-PLA₂R antibody was negative, and the 24-hour total urine protein and serum albumin was 4.4 g and 34 g/L, respectively. This case suggested the potential efficacy of rituximab for refractory membranous nephropathy. Further studies should explore whether the titer of anti-PLA₂R antibody indicates the dose of rituximab.

Global Forum of Cancer Surgeons: Cancer Surgery During the COVID-19 Pandemic: Impact and Lessons Learned

Background

The purpose of this article is to summarize the opinions of the surgical oncology leaders from the Global Forum of Cancer Surgeons (GFCS) about the global impact of COVID-19 pandemic on cancer surgery.

Methods

A panel session (virtual) was held at the annual Society of Surgical Oncology 2021 International Conference on Surgical Cancer Care to address the impact of COVID-19 on cancer surgery globally. Following the virtual meeting, a questionnaire was sent to all the leaders to gather additional opinions. The input obtained from all the leaders was collated and analyzed to understand how cancer surgeons from across the world adapted in real-time to the impact of COVID-19 pandemic.

Results

The surgical oncology leaders noted that the COVID-19 pandemic led to severe disruptions in surgical cancer care across all domains of clinical care, education, and research. Several new changes/protocols associated with increased costs were implemented to deliver safe care. Leaders also noted that preexisting disparities in care were exacerbated, and the pandemic had a detrimental effect on well-being and financial status.

Conclusions

The COVID-19 pandemic has led to severe disruptions in surgical cancer care globally. Leaders of the GFCS opined that new strategies need to be implemented to prepare for any future catastrophic events based on the lessons learned from the current events. The GFCS will embark on developing such a roadmap to ensure that surgical cancer care is preserved in the future regardless of any catastrophic global events.

[Reconstruction of teaching mode of Human Parasitology among rural order-oriented medical students in the context of curriculum ideology and politics]

To set the cultivation goal with adaptation to rural order-oriented medical students, the teaching mode of Human Parasitology was reformed in the context of curriculum ideological and political education. The new teaching mode not only enables students to harvest medical knowledge during the school education stage, but also plays a guiding role in cultivation of humanistic qualities and professional spirit, which provides a basis for cultivating general practitioners serving for grassroots healthcare.

Measurement of the Cross Section for e^{+}e^{-}→Hadrons at Energies from 2.2324 to 3.6710 GeV

Based on electron-positron collision data collected with the BESIII detector operating at the Beijing Electron-Positron Collider II storage rings, the value of R≡σ(e^{+}e^{-}→hadrons)/σ(e^{+}e^{-}→μ^{+}μ^{-}) is measured at 14 center-of-mass energies from 2.2324 to 3.6710 GeV. The resulting uncertainties are less than 3.0% and are dominated by systematic uncertainties.

[A cohort study on the influence of the chronic diseases on falls among middle-aged and older Chinese]

Objective: To analyze the influence of chronic diseases on falls among middle-aged and older Chinese. Methods: Baseline data of 13 670 middle-aged and older adults recruited from China Health and Retirement Longitudinal Study (CHARLS) in 2011 were used and followed up to 2018, among those were 7 443 (54.45%) middle-aged people aged 45-59 and 6 227 (45.55%) older adults aged 60 and above. The Cox proportional hazards model was used to analyze the effects of different types, the number of chronic diseases and the interaction between chronic illness and other factors on the fall risk of middle-aged and older people. Results: After adjusting for confounding factors, respiratory diseases increased the risk of falls by 21% (HR=1.21, 95%CI:1.02-1.45), and arthritis increased the risk of falls by 27% (HR=1.27,95%CI: 1.12-1.43) in the group aged 45-59, kidney disease increased the risk of falls by 26% (HR=1.26, 95%CI: 1.03-1.53) in the group aged 60 and above. A linear dose-response relationship between the number of chronic diseases and fall risk (χ2=133.61, P<0.001) was found in all the age groups. The interaction between having chronic diseases and the factors of females (HR=1.64, 95%CI: 1.43-1.89), impaired activities of daily living (ADL) (HR=1.66, 95%CI: 1.39-1.99), and having a fall history (HR=2.58, 95%CI: 2.24-2.97) increased the risk of falls. Conclusions: There is a positive linear relationship between the number of chronic diseases and the fall risk among Chinese aged 45 and above. The female middle-aged and elderly patients with chronic diseases and the middle-aged and elderly patients with impaired ADL or a history of falls are the high-risk groups for falls that need to be focused on intervention. The window of fall injury prevention should be moved forward to the middle-aged stage in time.