[Analysis of factors influencing the efficacy and prognosis of surgical treatment for primary malignant pelvic bone tumors]

Objective: To analyze the prognostic factors and the influence of surgical margin to prognosis. Methods: A retrospective analysis was performed for 208 pelvic tumors who received surgical treatment from January 2000 to December 2017 in our instituition. Survival analysis was performed using the Kaplan-Meier method and Log rank test, and impact factor analysis was performed using Cox regression models. Results: There were 183 initial patients and 25 recurrent cases. According to Enneking staging, 110 cases were stage ⅠB and 98 cases were stage ⅡB. 19 lesions were in zone Ⅰ, 1 in zone Ⅱ, 15 in zone Ⅲ, 29 in zone Ⅰ+Ⅱ, 71 in zone Ⅱ+Ⅲ, 29 in zone Ⅰ+Ⅳ, 35 in zone Ⅰ+Ⅱ+Ⅲ, 3 in zone Ⅰ+Ⅱ+Ⅳ, and 6 in zone Ⅰ+Ⅱ+Ⅲ+Ⅳ. Surgical margins including Intralesional excision in 7 cases, contaminated margin in 21 cases, marginal resection in 67 cases, and wide resection in 113 cases. Local recurrence occurred in 37 cases (17.8%), 25 cases were performed by reoperation and 12 cases received amputation finally. The 5-year recurrence rate of marginal resection was higher than wide resection (P＜0.05), and the recurrence-free survival rate of marginal resection was lower than wide resection (P＜0.05). There was significant differences in recurrence rate and recurrence-free survival rate between R0 and R1 resection (P＜0.05). 92 cases were not reconstructed and 116 cases were reconstructed after pelvic surgery. At the last follow-up, 63 patients (30.3%) died, and the 5-year, 10-year and 15-year survival rates were 70.4%, 66.8% and 61.3%, respectively. The 5-year survival rate of stage ⅠB and ⅡB tumor was 90.4% and 46.8%, respectively. There were 29 cases had postoperative wound complications (13.8%), 1 case with pelvic organ injury. The final function was evaluated in 132 patients, with an average MSTS score of 25.1±3.6. Cox multivariate analysis showed that surgical staging, R0/R1 margin and metastasis were independent prognostic factors for pelvic tumors. Conclusions: The safe surgical margin is the key factor for recurrence-free of pelvic tumor. The survival rate of stage ⅡB pelvic tumors was significantly lower than that of stage ⅠB tumors. Wound infection is the main postoperative complication. Surgical staging, R0/R1 margin and metastasis were independent prognostic factors of pelvic tumors.

Observation of Seven Astrophysical Tau Neutrino Candidates with IceCube

We report on a measurement of astrophysical tau neutrinos with 9.7 yr of IceCube data. Using convolutional neural networks trained on images derived from simulated events, seven candidate ν_{τ} events were found with visible energies ranging from roughly 20 TeV to 1 PeV and a median expected parent ν_{τ} energy of about 200 TeV. Considering backgrounds from astrophysical and atmospheric neutrinos, and muons from π^{±}/K^{±} decays in atmospheric air showers, we obtain a total estimated background of about 0.5 events, dominated by non-ν_{τ} astrophysical neutrinos. Thus, we rule out the absence of astrophysical ν_{τ} at the 5σ level. The measured astrophysical ν_{τ} flux is consistent with expectations based on previously published IceCube astrophysical neutrino flux measurements and neutrino oscillations.

Imaging features of temporomandibular joint synovial chondromatosis with associated osseous degenerative changes

Synovial chondromatosis (SC) of the temporomandibular joint (TMJ) is a rare benign disease associated with the formation of multiple cartilaginous nodules in the synovial tissue of the TMJ. This can result in pain, swelling, clicking, limited mouth opening, and osseous degenerative joint changes. A retrospective cross-sectional study was performed to summarize the clinical features, radiographic findings, and surgical and histopathological findings of TMJ SC patients who underwent open surgery over a 24-year period. A radiographic scoring system was used to evaluate osseous changes and correlate condyle and joint fossa degeneration. The study included 38 patients and focused on 38 joints. All 38 of these joints showed degenerative changes in the condyle, while 37 showed osseous degenerative changes in the articular fossa. The degree of condylar degenerative changes was related to the duration of the chief complaints (r = 0.342, P = 0.036) and the histopathological stage of the TMJ SC (r = 0.440, P = 0.006), while the degree of joint fossa degenerative changes was associated with the radiographic extent of the SC (r = 0.504, P = 0.001), type of calcification (r = 0.365, P = 0.024), and the histopathological stage (r = 0.458, P = 0.004).

Labile assembly of a tardigrade protein induces biostasis

Tardigrades are microscopic animals that survive desiccation by inducing biostasis. To survive drying tardigrades rely on intrinsically disordered CAHS proteins, which also function to prevent perturbations induced by drying in vitro and in heterologous systems. CAHS proteins have been shown to form gels both in vitro and in vivo, which has been speculated to be linked to their protective capacity. However, the sequence features and mechanisms underlying gel formation and the necessity of gelation for protection have not been demonstrated. Here we report a mechanism of fibrillization and gelation for CAHS D similar to that of intermediate filament assembly. We show that in vitro, gelation restricts molecular motion, immobilizing and protecting labile material from the harmful effects of drying. In vivo, we observe that CAHS D forms fibrillar networks during osmotic stress. Fibrillar networking of CAHS D improves survival of osmotically shocked cells. We observe two emergent properties associated with fibrillization; (i) prevention of cell volume change and (ii) reduction of metabolic activity during osmotic shock. We find that there is no significant correlation between maintenance of cell volume and survival, while there is a significant correlation between reduced metabolism and survival. Importantly, CAHS D's fibrillar network formation is reversible and metabolic rates return to control levels after CAHS fibers are resolved. This work provides insights into how tardigrades induce reversible biostasis through the self-assembly of labile CAHS gels.

Study on the construction of nomogram prediction model for prognostic assessment of heart failure patients based on serological markers and echocardiography

OBJECTIVE

We aimed to construct a nomogram prediction model for prognostic assessment of patients with heart failure (HF) based on serological markers and echocardiography.

PATIENTS AND METHODS

A total of 200 HF patients admitted to the Second Affiliated Hospital of Nanchang University from January 2018 to January 2020 were selected as the research objects. According to the New York Heart Association (NYHA) cardiac function classification, they were divided into 3 groups, including 65 cases of grade II, 97 cases of grade III, and 38 cases of grade IV. Three groups of echocardiographic parameters were compared [including left ventricular ejection fraction (LVEF), left ventricular end-diastolic diameter (LVEDD), left ventricular end-systolic diameter (LVESD), left ventricular end-systolic volume (LVESV)], differences in serum markers brain natriuretic peptide (BNP), soluble growth-stimulating expression gene 2 (sST2) and the Modified Early Warning Score (MEWS). The patients were divided into two groups according to their clinical outcomes during the follow-up period, including 52 cases in the death group and 148 cases in the survival group. The clinical data of the two groups were compared, and multi-factor logistic regression analysis was performed to screen out the independent risk factors affecting the patient's death. A nomogram model of the patient's mortality risk was constructed based on the independent risk factors. Receiver operating characteristic (ROC) curves and calibration curves were used to evaluate the discrimination and accuracy of the nomogram model.

RESULTS

As the cardiac function class of elderly chronic heart failure (CHF) patients increases, LVEDD, LVESD, sST2, and MEWS increase and LVEF decreases (p<0.05). Multifactor analysis results showed that LVEF, LVEDD, sST2, and MEWS were independent factors affecting the clinical outcome of patients. The AUCs predicted using LVEF, LVEDD, sST2, and MEWS alone were 0.738, 0.775, 0.717, 0.831, and 0.768, respectively. There is a certain degree of discrimination, and the model has extremely high accuracy.

CONCLUSIONS

MEWS, LVEDD, and sST2 increase as the NYHA cardiac function grade of HF patients increases and LVEF decreases, which can reflect the severity of the disease to a certain extent. Additionally, the nomogram model established based on this has a high predictive value for the long-term prognosis of patients and can formulate effective intervention measures for quantitative values.

HMGN1 down-regulation in the diabetic kidney attenuates tubular cells injury and protects against renal inflammation via suppressing MCP-1 and KIM-1 expression through TLR4

BACKGROUND

Renal tubular injury, accompanied by damaging inflammation, has been identified to drive diabetic kidney disease (DKD) toward end-stage renal disease. However, it is unclear how damage-associated molecular patterns (DAMPs) activate innate immunity to mediate tubular epithelial cell (TEC) injury, which in turn causes with subsequent sterile inflammation in diabetic kidneys. High mobility group nucleosome-binding protein 1 (HMGN1) is a novel DAMP that contributes to generating the innate immune response. In this study, we focused on determining whether HMGN1 is involved in DKD progression.

METHODS

Streptozotocin (STZ)-induced diabetic mice model was established. Then we downrergulated HMGN1 expression in kidney with or without HMGN1 administration. The renal dysfunction and morphological lesions in the kidneys were evaluated. The expressions of KIM-1, MCP-1, F4/80, CD68, and HMGN1/TLR4 signaling were examined in the renal tissue. In vitro, HK2 cells were exposed in the high glucose with or without HMGN1, and further pre-incubated with TAK242 was applied to elucidate the underlying mechanism.

RESULTS

We demonstrated that HMGN1 was upregulated in the tubular epithelial cells of streptozotocin (STZ)-induced type 1 and type 2 diabetic mouse kidneys compared to controls, while being positively correlated with increased TLR4, KIM-1, and MCP-1. Down-regulation of renal HMGN1 attenuated diabetic kidney injury, decreased the TLR4, KIM-1, and MCP-1 expression levels, and reduced interstitial infiltrating macrophages. However, these phenotypes were reversed after administration of HMGN1. In HK-2 cells, HMGN1 promoted the expression of KIM-1 and MCP-1 via regulating MyD88/NF-κB pathway; inhibition of TLR4 effectively diminished the in vitro response to HMGN1.

CONCLUSIONS

Our study provides novel insight into HMGN1 signaling mechanisms that contribute to tubular sterile injury and low-grade inflammation in DKD. The study findings may help to develop new HMGN1-targeted approaches as therapy for immune-mediated kidney damage rather than as an anti-infection treatments.

Norovirus outbreaks in hospitals in China: a systematic review

BACKGROUND

Norovirus outbreaks in hospitals can potentially impair patient care and result in significant financial expenses. There is currently limited information on hospital norovirus outbreaks in the Chinese mainland.

AIM

To systematically review the published literature to describe the characteristics of norovirus outbreaks in Chinese mainland hospitals to facilitate prompt identification and control of outbreaks.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis standards. Databases including PubMed, Web of Science, and Chinese Journals Online databases (China National Knowledge Infrastructure (CNKI), Chinese Wan Fang digital database (WANFANG) were searched from inception to July 18th, 2022.

FINDINGS

A total of 41 norovirus Chinese hospital outbreaks occurring before July 18th, 2022 were reported in 32 articles. Most reported outbreaks were from Shanghai and Beijing, and occurred in December and January. Cases were mainly adults. The male:female ratio was 1.22:1. The majority of cases in norovirus outbreaks were hospitalized patients (56.82%); medical staff were affected in 15 outbreaks. Norovirus outbreaks occurred in both private and public hospitals, and in secondary and tertiary care centres, and occurred mainly in internal medicine and geriatric departments. Person-to-person transmission was the primary transmission mode and GII was more prevalent.

CONCLUSION

Norovirus outbreaks in hospitals can affect both patients and healthcare workers, sometimes causing serious financial losses. In order to have a more complete understanding of the disease burden caused by norovirus outbreaks, surveillance needs to be established in hospitals.

[Vaginal microbiota abnormalities in women with unexplained infertility and its treatment]

The vaginal microbiota is a complex and dynamic environment that plays an important role in the healthy reproduction of women. The mechanism of unexplained infertility is not yet clear, and the imbalance and low stability of vaginal microbiota may be related to unexplained infertility. Taking probiotic composite preparations to restore normal vaginal microbiota may be a safe and natural method for treating unexplained infertility. This article reviews the probiotic composite preparations used in the treatment of unexplained infertility both domestically and internationally, including the isolation site of the bacterial species, the use method of the composite preparation, the course of treatment, and the final therapeutic effect, aiming to provide a basis for the clinical application of probiotic composite preparations in the treatment of unexplained infertility.

Introducing an Experimental Approach to Predict Spot Scanning Time Parameters for a Superconducting Cyclotron Proton Therapy Machine

PURPOSE/OBJECTIVE(S)

Proton pencil beam scanning (PBS) delivery sequence varies a lot among institutions due to the differences in vendors, machine types, and beamline configurations, which impacts PBS interplay effects and treatment delivery time estimation. This study aims to develop an independent experimental approach to predict the spot scanning time parameters for a clinical superconducting cyclotron proton therapy machine.

MATERIALS/METHODS

This independent experimental approach employed an open-air parallel-plate detector with a temporal resolution of 0.05ms. A series of spot, energy, and dose rate patterns were designed and delivered, including (1) Spot switching time (SSWT) under different spot spacing for IEC-X, IEC-Y directions and diagonal direction (traveling in both X and Y direction) for three energy layers (110, 170 and 230 MeV); The Wilcoxon test is used to validate the prediction of SSWT along the diagonal direction. (2) Energy layer switching time (ELST) with different descending energy gaps for a fixed initial energy and different initial energies for a fixed descending energy gap. (3) Dose rate (MU/min) are measured for different minimum-MU-per-energy-layer (MMPEL), which are compared with the previous publication.

RESULTS

A SSWT jump at 10mm (can be customized) spot spacing is observed because of triggering the machine's "raster mode" threshold. Discontinuous two variable piecewise linear functions were used to fit the SSWT in X/Y for spot spacing and energy. SSWT in X/Y is increasing as spot spacing and energy increase. SSWT in the diagonal direction is determined by the time either in the x-direction or y-direction, whichever takes longer (see Table 1 for one example of validations). ELST is linear depending on descending energy gap. The dose rate dependence on MMPEL is confirmed with previous publications of a similar type of machine.

CONCLUSION

The study provided the first independent quantitative experimental modeling of the beam delivery time parameters without any information from vendors. Such machine-specific delivery sequence models could pave the foundation of precise interplay effect evaluation for clinical decision-making.

Pencil Beam Scanning Proton Stereotactic Body Radiation Therapy (SBRT): A Robust Single Institution Experience

PURPOSE/OBJECTIVE(S)

To describe the feasibility of treating a complex and diverse group of patients using pencil beam scanning (PBS) proton stereotactic body radiation therapy (SBRT: 5 or fewer fractions, with a fraction size of at least 5 Gy).

MATERIALS/METHODS

Our center treats on average 105-120 PBS proton treatments daily, of which 9.5% of treatment courses are proton SBRT. Statistics of disease sites, treatment planning parameters (target volume, prescriptions, number of fields, SFO vs. MFO), and treatment efficiencies (scheduled time slots, actual treatment time) are presented for 305 consecutive SBRT patients receiving 1507 fractions in the past three years. Thermoplastic masks or Vacuum-lock bags are used to immobilize SBRT patients and index the patients' treatment position. Imaging guidance of orthogonal kV images and volumetric cone-beam CT is routinely used for patient setup.

RESULTS

SBRT patients are grouped based on the target locations: pelvis (31%), liver (17%), thoracic (13%), spine (8%), abdominal (8%), brain (7%), non-spine bone (7%), ocular (6%), and head and neck (2%). Only 112 patients (37%) were receiving their 1st RT course, whereas 113 (37%) had one prior in-field RT course, and 80 (26%) had multiple prior in-field RT courses. The median [IQR] target volume was 65.4 [29.3, 168] cc (range: 0.3-2475 cc). 72% of cases were planned with SFO and 28% with MFO. On average, 3.76 fields (range: 2 to 12) were planned for each treatment. 44% of the treatments were planned with three or fewer fields, and 10% received more than five fields, most of which involved repainting for moving targets. Over 97% of treatments were delivered in 5 fractions, with ∼3% delivered in 3 fractions. The median [IQR] prescription per treatment was 8 [7, 10] Gy (range: 5-18 Gy per treatment). 85% (84%) of the SBRT treatments were scheduled (delivered) in a 45-minute or shorter slot, and 6% (7%) of treatments were scheduled (delivered) in over a one-hour slot, most commonly for multiple isocenter treatments. 93% of treatments were delivered within 15 minutes of the planned treatment time or shorter. Deep-inspiration breath-hold (DIBH) was applied to 45% of liver SBRT cases, with the remaining 55% planned on 4D CT with (14%) or without (86%) abdominal compression. DIBH was applied in 13% of lung SBRT cases. The application of other motion mitigation approaches, such as volumetric repainting, was determined by the target motion amplitude and whether the patient could tolerate DIBH.

CONCLUSION

In the most diverse and largest proton SBRT experience delivered in the world over the past 3 years, over 300 patients were treated, demonstrating the feasibility and efficiency of delivering proton SBRT in a very busy center. The planning and treatment parameter statistics reported serve as a helpful reference for the proton community.

Prospective Evaluation of Patient-Reported Outcomes of Invisible Ink Tattoos for the Delivery of External Beam Radiation Therapy: The PREFER Trial

PURPOSE/OBJECTIVE(S)

Invisible ink tattoos allow for setup accuracy while avoiding the cosmetic permanence of visible ink tattoos. The goal of this trial was to evaluate patient-reported preference for the use of invisible ink tattoos in a radiation oncology clinic.

MATERIALS/METHODS

In an IRB-approved, prospective, feasibility trial, patients at a single institution receiving pencil beam scanning proton therapy to the thorax, abdomen, or pelvis underwent invisible ink tattoo-based treatment setup. Patient preference surveys comparing visible and invisible ink tattoos were completed prior to simulation (17 questions), immediately following simulation (5 questions), and at the end of treatment (18 questions), with preference scored on a 5-point Likert scale from strongly disagree to strongly agree, and cosmesis scored on a 4-point Likert scale of excellent-good-fair-poor. Differences in distributions were examined using Wilcoxon rank-sum tests, Fisher's exact tests, or chi-square tests, where statistical significance was considered at p<0.05.

RESULTS

Of 107 patients screened, 102 were enrolled and 94 completed all surveys. Mean age was 55.0 years, and 58.5% were female. Most patients were white (79.1%) and non-Hispanic (92.6%). Patients most commonly had breast (34.0%), prostate (16.0%), and lung (9.6%) cancer. An average of 5 (range 3-8) invisible ink tattoos were placed per patient. Overall, 75.5% of patients reported that they would prefer to receive invisible tattoos vs. visible tattoos, and 88.3% rated the overall cosmetic outcome of invisible ink tattoo marks as excellent or good. Compared to males, females were more willing to travel farther from their home in order to avoid receiving visible tattoos (45.4% vs. 23.1%, p = 0.035) and would pay additional money to avoid receiving visible tattoos (34.5% vs. 5.1%, p = 0.002). Patients who had previously received any tattoo (cosmetic or visible RT tattoos) were more satisfied with the appearance of their invisible ink tattoos compared to those who had never previously received tattoos (82.9% vs. 61.5%, p = 0.022). Patients receiving definitive intent RT were more satisfied with the appearance of the tattoos compared to those receiving palliative intent RT (67.1% vs. 38.9%, p = 0.011). Patients with at least a college education were less satisfied with the appearance of tattoos compared to those without a college education (67.0% vs. 95.0% p = 0.018).

CONCLUSION

These findings demonstrate stronger avoidance of visible tattoos and patient preference for invisible tattoos. The standard incorporation of invisible ink tattoos for patient setup should be strongly considered.

A Dosimetric Assessment of Sexual Organ Sparing Proton Radiotherapy in Female Pelvic Cancer Patients

PURPOSE/OBJECTIVE(S)

Optimizing treatment techniques for female patients undergoing curative treatment for pelvic cancers requires incorporating the goals of maximizing cure while maintaining quality of life. Optimizing treatment to maintain sexual quality of life has received little attention in female patients despite the presence of and toxicity risks to functional anatomic organs and their associated neurovasculature, including the bulboclitoris, vagina, and ovaries. Recent dosimetric data without employing sexual organ sparing suggest that mean VMAT dose to the bulboclitoris in low rectal cancer is around 3300 cGy, and in anal cancer, mean dose is around 2000 cGy to the external genitalia and 4500-5000 cGy to the bulboclitoris, all of which would be expected to result in clinically significant toxicity. Therefore, investigation of the avoidance of these important organs is needed and we hypothesize that proton techniques may achieve greater sparing than photon techniques.

MATERIALS/METHODS

In this study, we dosimetrically compare proton- vs. photon-based techniques in sparing functional sexual organs. The cohort consisted of four consecutive female pelvic cancer cases that had received 5000 cGy or greater. All cases were re-planned with VMAT and protons while optimizing dose to functional sexual organs and maintaining target coverage. Sexual organ structures assessed include the genitalia, vagina, ovaries, bulboclitoris and internal pudendal arteries. Given the small number of patients included in this demonstration study, statistical tests were not performed.

RESULTS

MRI was required to appropriately delineate soft tissue. In all cases, dosimetric sparing of sexual organs was improved with proton therapy without compromising target coverage. Mean doses were marginally decreased for structures within the PTV, while structures such as the bulboclitoris were spared substantially. Mean dose to the external genitalia was low with sparing using both VMAT (Median [IQR] (cGy): 852 [811, 1090]) and Proton techniques (Median [IQR] (cGy): 39.4 [11.9, 78.5]). Similarly, mean dose with sparing to the external genitalia was lower than would be expected without sparing, using both VMAT and Proton techniques (Median (IQR) Dmean (cGy) VMAT 3100 [2890, 3580] vs. Proton 1530 [1100, 2090]), with protons demonstrating greater sparing. In one case of a sacral chordoma, ovaries were substantially spared to below ablative thresholds (Dmean (cGy) VMAT 3598.8 and 3548.0 vs Proton 34.1 and 103.3).

CONCLUSION

Magnetic resonance imaging at simulation combined with proton radiotherapy for female sexual organ sparing may provide a technically feasible route to more equitable sexual outcomes for female patients. These results will guide future studies to optimize proton treatment techniques for female sexual organ sparing for future trials.

Photoactivated DNA Assembly and Disassembly for On-Demand Activation and Termination of cGAS-STING Signaling

Despite significant progress in DNA self-assembly for interfacing with biology, spatiotemporally controlled regulation of biological process via in situ dynamic DNA assembly remains an outstanding challenge. Here, we report an optically triggered DNA assembly and disassembly strategy that enables on-demand activation and termination of the cyclic GMP-AMP synthase (cGAS)-stimulator of interferon genes (STING) signaling pathway. In the design, an activatable DNA hairpin is engineered with a photocleavable group at defined site to modulate its self-assembly activity. Light activation induces the configurational switching and consequent self-assembly of the DNA hairpins to form long linear double-stranded structures, allowing to stimulate cGAS protein to synthesize 2',3'-cyclic-GMP-AMP (cGAMP) for STING stimulation. Furthermore, by endowing the pre-assembled DNA scaffold with a built-in photolysis feature, we demonstrate that the cGAS-STING stimulation can be efficiently terminated through remote photo-triggering, providing for the first time a route to control the temporal "dose" on-demand for such a stimulation. We envision that this regulation strategy will benefit and inspire both fundamental research and therapeutic applications regarding the cGAS-STING pathway.

[Status and associated factors of pre-exposure prophylaxis use among men who have sex with men in 24 cities in China]

Objective: To understand the cognition and medication use of pre-exposure prophylaxis (PrEP) among men who have sex with men (MSM) in China and its associated factors. Method: From August 25 to September 5, 2021, 2 447 MSM were recruited in 24 cities to complete the online questionnaire through a male social interaction platform, Blued 7.5 software. The survey contents included demographic information of the respondents, PrEP awareness and usage, and risk behaviors. Descriptive analysis and multi-level logistic regression were performed for data analysis. SPSS 24.0 and SAS 9.4 software were used for statistical analysis. Results: Among the 2 447 respondents of MSM, 1 712 (69.96%) had heard of PrEP, 437 (17.86%) ever used PrEP, 274 (11.20%) were on PrEP, and 163 (6.66%) had discontinued PrEP; among the 437 cases (whoever used PrEP), more than 61.88% (388/627) adopted emtricitabine/tenofovir disoproxil fumarate regimen, and most of them adopted on-demand regimen. The average PrEP dosage reported in the past year is 1.12 tabletsper person per week. PrEP purchase was primarily via an online channel, and the most concerned factor was the PrEP effectiveness on HIV prevention. The most common reasons for discontinuing PrEP, reported by 163 cases, were the lack of HIV risk perception, the use of a condom to prevent HIV, and the economic burden of PrEP use. The logistic regression analysis showed that PrEP use among MSM in 24 cities was statistically associated with age, monthly income, ever having unprotected anal sex in the past year, used sexual drugs and sexually transmitted disease (STD) diagnosis in the past year. Compared with MSM aged 18-24, the proportion of MSM was relatively lower among those aged 25-44, who discontinued the PrEP (aOR=0.54,95%CI:0.34-0.87) or never used PrEP (aOR=0.62,95%CI:0.44-0.87). The proportion of unprotected anal sex among MSM currently on PrEP use was higher than those who have stopped PrEP and never used PrEP (all P<0.05). Those MSM group, with monthly income higher than 5 000 Yuan, used sexual drugs and STD diagnosis in the past year were more likely to have a higher rate for PrEP usage (all P<0.05). Conclusions: Currently, pre-exposure prophylaxis in the MSM group is primarily obtained via the online channel and adopted in an on-demand mode. Although the PrEP users have reached a certain proportion, it is still necessary to strengthen health education on the PrEP effects and side effects of MSM and to improve the awareness and use rate, especially for young MSM group, which can be combined with the advantages of the internet targeting its needs and use barriers.

Enzyme Translocation-Mediated Signal Amplification for Spatially Selective Aptasensing of ATP in Inflammatory Cells

Amplified ATP imaging in inflammatory cells is highly desirable. However, the spatial selectivity of current amplification methods is limited, that is, signal amplification is performed systemically and not in a disease site-specific manner. Here we present a versatile strategy, termed enzymatically triggerable, aptamer-based signal amplification (ETA-SA), that enables inflammatory cell-specific imaging of ATP through spatially-resolved signal amplification. The ETA-SA leverages a translocated enzyme in inflammatory cells to activate DNA aptamer probes and further drive cascade reactions through the consumption of hairpin fuels, which, however, exerts no ATP response activity in normal cells, leading to a significantly improved sensitivity and spatial specificity for the inflammation-specific ATP imaging in vivo. Benefiting from the improved spatial selectivity, enhanced signal-to-background ratios were achieved for ATP imaging during acute hepatitis.

Flanking strand separation activity of RecA nucleoprotein filaments in DNA strand exchange reactions

The recombinase RecA/Rad51 ATPase family proteins catalyze paramount DNA strand exchange reactions that are critically involved in maintaining genome integrity. However, it remains unclear how DNA strand exchange proceeds when encountering RecA-free defects in recombinase nucleoprotein filaments. Herein, by designing a series of unique substrates (e.g. truncated or conjugated incoming single-stranded DNA, and extended donor double-stranded DNA) and developing a two-color alternating excitation-modified single-molecule real-time fluorescence imaging assay, we resolve the two key steps (donor strand separation and new base-pair formation) that are usually inseparable during the reaction, revealing a novel long-range flanking strand separation activity of synaptic RecA nucleoprotein filaments. We further evaluate the kinetics and free energetics of strand exchange reactions mediated by various substrates, and elucidate the mechanism of flanking strand separation. Based on these findings, we propose a potential fundamental molecular model involved in flanking strand separation, which provides new insights into strand exchange mechanism and homologous recombination.

Chronological and Replicative Aging of CD51+/PDGFR-α+ Pulp Stromal Cells

As a crucial source of mesenchymal stromal cells, CD51⁺/PDGFR-α⁺ human dental pulp stromal cells (hDPSCs) are promising seeding cells for regenerative medicine. Cellular senescence hinders the translational application of hDPSCs. However, it remains unclear whether chronological and replicative senescence results in distinct outcomes for hDPSCs. To investigate the influence of senescence on DPSCs, we used transgenic lineage tracking, immunofluorescence, flow cytometry, and various molecular experiments to depict the dynamic pattern of hDPSCs in mice and humans during chronological and replicative senescence. The data demonstrated that CD51⁺/PDGFR-α⁺ cells were decreased in chronological senescence. Impaired self-renewal and higher ossificatory differentiation were observed in chronologically senescent hDPSCs. Regarding replicative senescence, a decreased CD51⁺ but upregulated PDGFR-α⁺ population was observed in culture. Furthermore, weakened self-renewal and osteogenic differentiation were observed in replicatively senescent hDPSCs. In summary, CD51⁺/PDGFR-α⁺ hDPSCs decrease in chronologically aged pulp, with self-renewal that is impaired without impaired osteogenic differentiation. However, replicative senescence has a different impact: self-renewal and ossific differentiation are impaired and CD51 expression is reduced, but PDGFR-α expression remains. These findings demonstrate the different outcomes of chronological and replicative senescence in CD51⁺/PDGFR-α⁺ hDPSCs. Furthermore, we revealed that impaired self-renewal is the core dysfunction for both types of cellular aging and that osteogenic differentiation capability differs between them. This study provides insights into the influence of chronological and replicative senescence on the characteristics and capabilities of hDPSCs. These advances provide fundamental knowledge to alleviate cellular aging of CD51⁺/PDGFR-α⁺ hDPSCs and promote their translational applications.

[Research advances in the application of bone metabolic markers in children's diseases associated with growth and development]

The incidence of children's growth and development diseases such as rickets, obesity, dwarfism and precocious puberty has increased year by year recently. The occurrence and development of these diseases are often closely related to children's malnutrition and endocrine disorders. Plenty of studies have indicated that bone is not only the structural scaffold of human body, but also an important endocrine and hormone target organ. As a series of substances closely related to bone formation and bone resorption, the levels of bone metabolic markers have been confirmed to change in the course of many children's growth and development diseases. The characteristics, classification and application of bone metabolism markers in children's growth and development related diseases was summarized and commented in this article in order to provide reference for the prevention, early diagnosis and treatment effect monitoring of children's growth and development diseases.

[68Ga-PSMA-I&T PET/CT for assessment of tumor burden in primary lesions of treatmentnaïve prostate cancer]

OBJECTIVE

To investigate the value of ⁶⁸Ga-labeled prostate specific membrane antigen (PSMA) PET/CT for assessing tumor load in primary lesions for risk stratification and predicting metastasis of newly diagnosed prostate cancer (PCa).

METHODS

We retrospectively analyzed the data of 36 patients (mean age 71.3 ± 8.6 years, range 56 to 89 years) with newly diagnosed PCa undergoing ⁶⁸Ga-PSMA-I&T PET/CT from June 2018 to July 2019. SUVmax and SUVmean of the primary lesions were measured, and the primary PSMA tumor volume (PSMA-TV) and total lesion PSMA (TL-PSMA) were automatically measured and calculated in all the patients. The correlations of primary SUVmax, PSMA-TV, and TL-PSMA with PSA and Gleason score (GS) were analyzed, and SUVmax, PSMA-TV and TL-PSMA of the primary lesions were compared among different PCa subgroups.

RESULTS

SUVmax, PSMA-TV and TL-PSMA of the primary lesions were all correlated with PSA and GS (P < 0.05). PCa subgroup analysis showed that SUVmax, PSMA-TV and TL-PSMA were all significantly higher in patients with PSA >20 ng/mL than in those with PSA ≤20 ng/mL (P < 0.001), and were higher in patients with a GS ≥8 than in those with a GS ≤7 (P < 0.001). PSMA-TV and TL-PSMA were significantly higher in patients with tumor metastasis than in those without metastasis (P < 0.001), while SUVmax did not differ significantly with tumor metastasis. SUVmax (P=0.002), PSMA-TV (P < 0.001), and TL-PSMA (P < 0.001) were all significantly higher in high-risk group than in low-to moderate-risk group.

CONCLUSION

PSMA-TV and TL-PSMA of ⁶⁸Ga-PSMA-I&T PET/CT have potential value in predicting risk stratification and metastasis of newly diagnosed PCa.

[Influencing factors of suicidal ideation among men who have sex with men]

Objective: To investigate the prevalence of suicidal ideation among MSM, and to explore the influence of perceived social support and depression on suicidal ideation and the possible pathway. Methods: MSM who are ≥18 years, HIV-negative, and ever had sex with men (oral sex/anal sex) in the last year participated in is study. Cross-sectional survey and convenient sampling method were used to recruit MSM through a male social interaction platform Blued 7.5 software from December 2020 to March 2021, with a questionnaire survey. Demographic questionnaire, Perceived Social Support Questionnaire and Center for Epidemiologic Studies Depression Scale were employed to collect data. Mplus 8.3 was used for data analysis. Results: Among 1 394 eligible MSM participants, 25.7% (358/1 394) had suicidal ideation. Perceived social support could have a direct effect on suicidal ideation (β=-0.11, P=0.009), and an indirect effect on suicidal ideation through depression (β=-0.18, P<0.001). Conclusions: Suicidal ideation was found to be lower in MSM with a higher level of perceived social support and a lower level of depression. Using social media to improve MSM's perceived social support and reduce depressive symptoms might be an effective means to prevent suicidal ideation.

[Impact of multi-leaf collimator positioning accuracy on quality control of volumetric modulation arc therapy plan for cervical cancer treated with Elekta linear accelerator]

OBJECTIVE

To investigate the influence of positioning accuracy of the multi-leaf collimators (MLC) on the passing rate of the plan dose verification for volumetric modulation arc therapy (VMAT) of cervical cancer using an Elekta linear accelerator.

METHODS

The dose distributions were measured using Sun Nuclear's Mapcheck and Arccheck semiconductors matrix before and after MLC calibration in30 cervical cancer patients undergoing VMAT. Dosimetric comparisons were performed with 2D and 3D gamma passing rates of 3%, 3 mm and 2%, and 2 mm. The 3D gamma distribution was reconstructed with respect to the patient's anatomy using 3DVH software to evaluate the possible influence of MLC positioning accuracy.

RESULTS

Before and after MLC calibration, the gamma passing rates of Mapcheck were (88.80±1.81)% and (99.25 ± 0.53)% under 3% and 3 mm standard, respectively, with an average increase of 10.45%. The corresponding gamma passing rates of Arccheck were (87.61±1.98)% and (98.13±0.99)%, respectively, with an average increase of 10.52%. The gamma passing rates of 3DVH were (89.87±2.28)% and (98.3±1.15)%, respectively, with an average increase of 8.43%.

CONCLUSION

The MLC positioning accuracy is one of the main factors influencing dosimetric accuracy of VMAT for cervical cancer. The application of Autocal software facilitates MLC calibration and improves the accuracy and safety of VMAT delivery for cervical cancer.

Spatially Selective Monitoring of Subcellular Enzyme Dynamics in Response to Mitochondria-Targeted Photodynamic Therapy

Tracking spatial and temporal dynamics of bioactive molecules such as enzymes responding to therapeutic treatment is highly important for understanding of the related functions. However, in situ molecular imaging at subcellular level during photodynamic therapy (PDT) has been hampered by the limitations of existing methods. Herein, we present a multifunctional nanoplatform (termed as UR-HAPT) that is able to simultaneously monitor subcellular dynamics of human apurinic/apyrimidinic endonuclease 1 (APE1) during the near-infrared (NIR) light-mediated PDT. UR-HAPT was constructed by the combination of an upconversion nanoparticle-based PDT design and a mitochondria-targeting strategy with an APE1-responsive DNA reporter. Benefiting from the gain-of-function approach, activatable mitochondrial accumulation of APE1 in response to the oxidative stress was observed during the NIR light-triggered, mitochondria-targeted PDT process. We envision that this nanoplatform can be applicable to screen and evaluate potential enzyme inhibitors to improve the PDT efficacy.

[Efficiency and safety of peptide receptor radionuclide therapy in the treatment of metastatic neuroendocrine tumors]

The clinical data of 14 patients with neuroendocrine tumors who received Peptide Receptor Radionuclide Therapy (PRRT) from December 2018 to May 2021 were retrospectively analyzed. Among them, 2 patients demonstrated proprogressive disease, 2 patients had partial response, and 10 patients had stable disease. Grade 1-2 myelosuppression occurred in 5 patients. and 1 patient became grade 3 myelosuppression，which recovered to grade 2 after symptomatic treatment. No grade 2 or higher treatment-related renal toxicity was observed in any of the patients. PRRT is efficacy and no significant side effects for unresectable metastatic neuroendocrine tumors.

[Analysis of HIV-1 genetic subtype and pretreatment drug resistance among men who have sex with men infected with HIV-1 from 19 cities of 6 provinces in China]

Objective: To investigate the distribution of HIV-1 genetic subtypes and pretreatment drug resistance (PDR) among men who have sex with men (MSM) from 19 cities of 6 provinces in China. Methods: From April to November 2019, 574 plasma samples of ART-naive HIV-1 infected MSM were collected from 19 cities in Hebei, Shandong, Jiangsu, Zhejiang, Fujian, and Guangdong provinces, total ribonucleic acid (RNA) was extracted and amplified the HIV-1 pol gene region by nested polymerase chain reaction (PCR) after reverse transcription. Then sequences were used to construct a phylogenetic tree to determine genetic subtypes and submitted to the Stanford drug resistance database for drug resistance analysis. Results: A total of 479 samples were successfully amplified by PCR. The HIV-1 genetic subtypes included CRF01_AE, CRF07_BC, B, CRF55_01B, CRF59_01B, CRF65_cpx, CRF103_01B, CRF67_01B, CRF68_01B and unrecognized subtype, which accounted for 43.4%, 36.3%, 6.3%, 5.9%, 0.8%, 0.8%, 0.4%, 0.4%, 0.2% and 5.5%, respectively. The distribution of genetic subtypes among provinces is statistically different (χ²=44.141, P<0.001). The overall PDR rate was 4.6% (22/479), the drug resistance rate of non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, and protease inhibitors were 3.5% (17/479), 0.8% (4/479) and 0.2% (1/479), respectively. The PDR rate of recent infections was significantly higher than that of long-term infections (χ²=4.634, P=0.031). Conclusions: The HIV-1 genetic subtypes among MSM infected with HIV-1 from 19 cities of 6 provinces in China are diverse, and the distribution of subtypes is different among provinces. The overall PDR rate is low, while the PDR rate of recent infections was significantly higher than that of long-term infections, suggesting the surveillance of PDR in recent infections should be strengthened.

[Application of limiting antigen avidity enzyme immunoassay for estimating HIV-1 incidence in men who have sex with men]

Objective: To estimate the incidence of HIV-1 infection in men who have sex with men (MSM) in key areas of China through HIV-1 limiting antigen avidity enzyme immunoassay (LAg-Avidity EIA), analyze the deviation from the actual results and identify influencing factors, and provided reference for improving the accuracy of estimation results. Methods: Based on the principle of the cohort randomized study design, 20 cities were selected in China based on population size and the number of HIV-positive MSM. The sample size was estimated to be 700 according to the HIV-1 infection rate in MSM. MSM mobile phone app. was used to establish a detection appointment and questionnaire system, and the baseline cross-sectional survey was conducted from April to November 2019. LAg-Avidity EIA was used to identify the recent infected samples. The incidence of HIV-1 infection was calculated and then adjusted based on the estimation formula designed by WHO. The influencing factors were identified by analyzing the sample collection and detection processes. Results: Among the 10 650 blood samples from the participants, 799 were HIV-positive in initial screening, in which 198 samples (24.78%) missed during confirmation test. Only 621 samples were received by the laboratory. After excluding misreported samples, 520 samples were qualified for testing. A total of 155 samples were eventually determined as recent infection through LAg-Avidity EIA; Based on the estimation formula , the incidence of HIV-1 infection in MSM in 20 cities was 4.06% (95%CI:3.27%-4.85%), it increased to 5.53% (95%CI: 4.45%-6.60%)after the adjusting for sample missing rate. When the sample missing rate and misreporting rate were both adjusted, the incidence of HIV-1 infection in the MSM increased to 5.66% (95%CI:4.67%-6.65%). The actual incidence of HIV-1 infection in MSM in the 20 cities might be between 4.06% and 5.66%. Conclusions: Sample missing and misreporting might cause the deviation of the estimation of HIV-1 infection incidence. It is important to ensure the sample source and the quality of sample collection and detection to reduce the deviation in the estimation of HIV-1 infection incidence.

Equine chorionic gonadotropin pretreatment 15 days before fixed-time artificial insemination improves the reproductive performance of replacement gilts

Fixed-time artificial insemination (FTAI) technology uses exogenous reproductive hormones to regulate the sexual cycle and ovulation of sows without oestrus identification, which improves the sow breeding utilisation rate, reduces the number of non-productive days, and elevates the efficiency of pig farm management. In this study, we aimed to optimise FTAI procedures. Healthy 190-day-old and about 90 kg Large White × Landrace crossing breed replacement gilts (n = 166) which were of unknown reproductive status were randomly selected and divided into three groups: a control group (n = 62), an eCG-15D group in which the gilts were pretreated with equine chorionic gonadotropin (eCG) injection 15 days before starting FTAI (n = 50), and an eCG-20D group pretreated with eCG injection 20 days before starting FTAI (n = 54). All three groups were then subjected to the same conventional FTAI procedure. Pigs were orally administered Altrenogest (ALT, 20 mg per pig per day) for 18 days and then 42 h after ALT feeding was stopped, they were injected with 1 000 IU eCG followed by 100 μg GnRH 80 h later. The gilts were inseminated for the first time 24 h after gonadotropin-releasing hormone (GnRH) injection and then again 16 h later. After 42 h of ALT feeding, gilts in the eCG-15D group displayed a higher follicular diameter until artificial insemination (AI) than those from the other groups (P < 0.05). In addition, the ovulation times were the most synchronised in the eCG-15D group, with 100% of the gilts ovulating before the second AI on day 25 of FTAI. Furthermore, the gilts in the eCG-15D group achieved the highest pregnancy rate (92%), farrowing rate (90%), total pigs born (11.59), and pigs born alive (11.18). Together, the findings of this study demonstrate that reproductive performance can be optimised by pretreating gilts with eCG 15 days before conventional FTAI.

[Application of affinity capillary electrophoresis in the study of protein-DNA interactions]

Protein-DNA interactions play essential roles in various biological events that determine the cell fate. Research on the molecular mechanism of protein-DNA interactions has helped elucidate diverse fundamental life processes, thereby providing theoretical guidance for establishing clinical treatment and screening potential drug of target diseases. Furthermore, well-known protein-DNA interactions have been utilized to develop advanced bioengineering and bioanalytical techniques, therefore providing robust technical support for related research. Hence, it is important to establish sensitive and rapid analytical methods to study protein-DNA interactions. High-performance capillary electrophoresis (CE) has been widely used in many research fields such as chemistry, life sciences, and environmental sciences, mainly due to its advantages including ultra-high separation efficiency, extremely low sample consumption, and short analysis time. For instance, affinity capillary electrophoresis (ACE) has become an important analytical tool for investigating molecular interactions. In this paper, we review the applications of ACE in studying protein-DNA interactions since it was first proposed in 1992, addressing previous significant work in this field. Three major aspects have been summarized in this review: (1) brief introduction to the development of ACE technique; (2) applications of ACE in the fundamental research on the molecular mechanism of protein-DNA interactions; and (3) applications of well-known protein-DNA interactions in CE-based detection of target molecules and reactions. In the first aspect, along with the concept and separation modes of ACE, general strategies to enhance the analytical ability of ACE are briefly introduced. In the second aspect, the applications of ACE in studying several important protein-DNA interactions involving transcription factors (e.g., GCN4), DNA repair proteins (e.g., UvrA, UvrB, and RecA), and methylated DNA-binding proteins (MBDs) are reviewed. In the third aspect, the applications of well-known molecular interactions (e.g., antigen-antibody, aptamer-target, etc.) to facilitate CE-based detection of target molecules (e.g., DNA adducts, DNA methylation, microRNA, single nucleotide polymorphism, etc.) and target reactions (e.g., DNA strand exchange) are addressed. Finally, we prospect and discuss the advancements of ACE that can be established in future studies. The following two aspects should be improved in future ACE analysis: (1) the advantages of extremely low volume consumption and short analysis time should be fully utilized to develop sensitive and high-throughput CE platforms for the assessment of rare biological samples and massive uncertain samples, respectively; (2) ACE should be combined with other advanced techniques, such as DNA sequencing and mass spectrometry, to rapidly screen and identify the precise interacting sites of unknown protein-DNA interactions.

Metabolomics Changes of Serum and Tissues in Mice Died of Acute Tetracaine Poisoning

Abstract

Objective To study the changes of metabolites in serum and tissues （kidney, liver and heart） of mice died of acute tetracaine poisoning by metabolomics, to search for potential biomarkers and related metabolic pathways, and to provide new ideas for the identification of cause of death and research on toxicological mechanism of acute tetracaine poisoning. Methods Forty ICR mice were randomly divided into control group and acute tetracaine poisoning death group. The model of death from acute poisoning was established by intraperitoneal injection of tetracaine, and the metabolic profile of serum and tissues of mice was obtained by ultra-high performance liquid chromatography-electrostatic field orbitrap high resolution mass spectrometry （UPLC-Orbitrap HRMS）. Multivariate statistical principal component analysis （PCA） and orthogonal partial least square-discriminant analysis （OPLS-DA） were used, combined with t-test and fold change to identify the differential metabolites associated with death from acute tetracaine poisoning. Results Compared with the control group, the metabolic profiles of serum and tissues in the mice from acute tetracaine poisoning death group were significantly different. Eleven differential metabolites were identified in serum, including xanthine, spermine, 3-hydroxybutylamine, etc.; twenty-five differential metabolites were identified in liver, including adenylate, adenosine, citric acid, etc.; twelve differential metabolites were identified in heart, including hypoxanthine, guanine, guanosine, etc; four differential metabolites were identified in kidney, including taurochenodeoxycholic acid, 11, 12-epoxyeicosatrienoic acid, dimethylethanolamine and indole. Acute tetracaine poisoning mainly affected purine metabolism, tricarboxylic acid cycle, as well as metabolism of alanine, aspartic acid and glutamic acid. Conclusion The differential metabolites in serum and tissues of mice died of acute tetracaine poisoning are expected to be candidate biomarkers for this cause of death. The results can provide research basis for the mechanism and identification of acute tetracaine poisoning.

Effect modification of the association between diurnal temperature range and hospitalisations for ischaemic stroke by temperature in Hefei, China

OBJECTIVES

Diurnal temperature range (DTR) is an important indicator of global climate change. Many epidemiological studies have reported the associations between high DTR and human health. This study investigated the association between DTR and hospitalisations for ischaemic stroke in Hefei, China.

STUDY DESIGN

This is an ecological study.

METHODS

Data of daily hospital admissions for ischaemic stroke and meteorological variables from 1 January 2009 to 31 December 2017 were collected in Hefei, China. A generalised additive model combined with distributed lag non-linear model was used to quantify the effects of DTR on ischaemic stroke. The interactive effect between DTR and temperature was explored with a non-parametric bivariate response surface model.

RESULTS

High DTR was associated with hospitalisations for ischaemic stroke. The adverse effect of extremely high DTR (99th percentile [17.1 °C]) occurred after 8 days (relative risk [RR] = 1.021, 95% confidence interval [CI] = 1.002, 1.041) and the maximum effect appeared after 12 days (RR = 1.029, 95% CI = 1.011, 1.046). The overall trend of the effect of DTR on ischaemic stroke was decreasing. In addition, there was a significant interactive effect of high DTR and low temperature on ischaemic stroke.

CONCLUSIONS

This study suggests that the impact of high DTR should be considered when formulating targeted measures to prevent ischaemic stroke, especially for those days with high DTR and low mean temperature.

Heterotrimeric G protein signalling in plant biotic and abiotic stress response

Heterotrimeric G proteins act as molecular switches to participate in transmitting various stimuli signals from outside of cells. G proteins have three subunits, Gα, Gβ and Gγ, which function mutually to modulate many biological processes in plants, including plant growth and development, as well as biotic and abiotic stress responses. In plants, the number of Gγ subunits is larger than that of the α and β subunits. Based on recent breakthroughs in studies of plant G protein signal perception, transduction and downstream effectors, this review summarizes and analyses the connections between different subunits and the interactions of G proteins with other signalling pathways, especially in plant biotic and abiotic stress responses. Based on current progress and unresolved questions in the field, we also suggest future research directions on G proteins in plants.

[HIV infection and related factors among men who have sex with men aged 50 and above]

Objectives: To explore the HIV prevalence and related factors among MSM aged 50 and above and provide evidence on the prevention and control of HIV/AIDS. Methods: Based on an MSM social application software Blued 7.1.6, we recruited participants through online convenience sampling to collect demographic variables, behavioral and self-reported HIV infection status, etc. Univariate χ2 test and multivariate logistic regression were used to analyze the related factors of self-reported HIV infection. Results: Self-reported HIV infection rate was 17.6%(126/714) among the participants. In multivariable analysis, participants who got divorced or widowed had a 2.07(95%CI: 1.34-3.21) times greater risk of self-reported HIV-positive than those who were married. Participants unaware of HIV-related knowledge showed a 1.92(95%CI:1.21-3.04) times greater risk of self-reported HIV-positive than those with better HIV-related knowledge. Participants who have ever been diagnosed with sexually transmitted disease (STD) showed a 3.17(95%CI:2.09-4.83) times greater risk of self-reported HIV-positive than those without STD infection history. Conclusion: Our findings indicated that the self-reported HIV infection rate was high among MSM aged 50 and above. Being divorced or widowed, being unaware of HIV-related knowledge and STD infection history was proved related with self-reported HIV infection.

[Exploration on contamination and transmission of SARS-CoV-2 in imported cold chain aquatic products]

Contaminations of SARS-CoV-2 have been found for many times in imported cold chain aquatic products and their packaging materials in China. The purpose of this paper is to analyze the contamination status, sources and transmission risks of SARS-CoV-2 in imported cold chain aquatic products, and try to put forward relevant suggestions and strategies in order to provide evidence for the prevention and control of SARS-CoV-2 infection.

Profiling of the assembly of RecA nucleofilaments implies a potential target for environmental factors to disturb DNA repair

Double-strand breaks (DSBs), one class of the most harmful DNA damage forms that bring elevated health risks, need to be repaired timely and effectively. However, an increasing number of environmental pollutants have been identified to impair DSB repair from various mechanisms. Our previous work indicated that the formation of unsaturated RecA nucleofilaments plays an essential role in homology recombination (HR) pathway which can accurately repair DSBs. In this study, by developing a benzonase cutting protection assay and combining it with traditional electrophoretic mobility shift assay (EMSA) analysis, we further investigated the assembly patterns of four RecA mutants that display differential DSB repair ability and ATPase activity. We observed that the mutants (G204S and S69G) possessing both ATP hydrolysis and DSB repair activities form unsaturated nucleofilaments similar to that formed by the wild type RecA, whereas the other two ATP hydrolysis-deficient mutants (K72R and E96D) that fail to mediate HR form more compacted nucleofilaments in the presence of ATP. These results establish a coupling of ATPase activity and effective DSB repair ability via the assembly status of RecA nucleofilaments. This linkage provides a potential target for environmental factors to disturb the essential HR pathway for DSB repair by suppressing the ATPase activity and altering the assembly pattern of nucleofilaments.

Sevoflurane inhibits neuronal apoptosis and expressions of HIF-1 and HSP70 in brain tissues of rats with cerebral ischemia/reperfusion injury

OBJECTIVE

To observe the influences of sevoflurane on neuronal apoptosis and expressions of hypoxia-inducible factor 1 (HIF-1), and heat-shock protein 70 (HSP70) in brain tissues of rats with cerebral ischemia/reperfusion (I/R) injury.

MATERIALS AND METHODS

A total of 60 Sprague-Dawley rats were selected and divided into sham-operation group (Sham group, n=20), cerebral I/R model group (Model group, n=20), and 3% sevoflurane treatment group (Sevoflurane group, n=20). The rats in each group received neurological scoring, and the blood and brain tissues were collected to detect the concentrations of serum K+, Na+ and glucose (Glu). Enzyme-linked immunosorbent assay (ELISA) was adopted to measure the levels of inflammatory factors [tumor necrosis factor-β (TNF-β) and interleukin-6 (IL-6)] and oxidative stress [catalase (CAT), malondialdehyde (MDA) and superoxide dismutase (SOD)]. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was performed to determine the nerve cell apoptosis in the brain tissues. The gene and protein expressions of Caspase-3, HIF-1, and HSP70 in the brain tissues were measured via quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) and Western blotting.

RESULTS

In Sevoflurane group, the content of serum Glu and Na+ was decreased markedly, that of K+ was increased notably, and the levels of TNF-β, IL-1 and IL-6 were lowered remarkably compared with those in Model group (p<0.05). Moreover, the neurological score was reduced evidently (p<0.05). Model group had significantly strengthened the activity of MDA and CAT and decreased SOD content, while Sevoflurane group exhibited the opposite results. TUNEL staining showed that there were distinctly more apoptotic cells that were dominated by glial cells in Model group and fewer apoptotic cells in Sevoflurane group. It was indicated in gene assay that the messenger ribonucleic acid (mRNA) expression levels of HIF-1, HSP70, and Caspase-3 in Model group were remarkably higher than those in Sham group and Sevoflurane group (p<0.05). According to the results of Western blotting, the protein expressions of HIF-1 and HSP70 in Sevoflurane group were markedly lower than those in Model group.

CONCLUSIONS

Sevoflurane can reduce the content of inflammatory factors, inhibit apoptosis, and reduce the expressions of HIF-1 and HSP70 in the case of cerebral I/R injury, thus exerting protective effects on rats with cerebral I/R injury.

A novel dentin bonding scheme based on extrafibrillar demineralization combined with covalent adhesion using a dry-bonding technique

Dentin bonding is a dynamic process that involves the penetration of adhesive resin monomers into the extrafibrillar and intrafibrillar demineralized collagen matrix using a wet-bonding technique. However, adhesive resin monomers lack the capacity to infiltrate the intrafibrillar space, and the excess water that is introduced by the wet-bonding technique remains at the bonding interface. This imperfectly bonded interface is inclined to hydrolytic degradation, severely jeopardizing the longevity of bonded clinical restorations. The present study introduces a dentin bonding scheme based on a dry-bonding technique, combined with the use of extrafibrillar demineralization and a collagen-reactive monomer (CRM)-based adhesive (CBA). Selective extrafibrillar demineralization was achieved using 1-wt% high-molecular weight (MW) carboxymethyl chitosan (CMCS) within a clinically acceptable timeframe to create a less aggressive bonding substance for dentin bonding due to its selectively extrafibrillar demineralization capacity. CMCS demineralization decreased the activation of in situ collagenase, improved the shrinking resistance of demineralized collagen, and thus provided stronger and more durable bonding than traditional phosphoric acid etching. The new dentin bonding scheme that contained CMCS and CBA and used a dry-bonding technique achieved an encouraging dentin bonding strength and durability with low technical sensitivity. This bonding scheme can be used to improve the stability of the resin-dentin interface and foster the longevity of bonded clinical restorations.

The antibacterial effect and physical performance of pit and fissure sealants based on an antibacterial core-shell nanocomposite

The application of pit and fissure sealants is a well-established method to prevent and treat early childhood caries. Resin-based sealants with antibacterial properties provide additional benefits for caries prevention in a cariogenic oral environment. The objective of this study was to evaluate the effect of an antibacterial core-shell AgBr/cationic polymer nanocomposite (AgBr/BHPVP) on the properties of a resin-based pit and fissure sealant. A commercialized pit and fissure sealant without fluoride, Concise (3M, ESPE, USA), was used as the parent material and negative control. Experimental antibacterial sealants were formulated by the addition of AgBr/BHPVP nanoparticles at mass fractions of 0.5, 1.0, and 1.5 wt% to the parent material. A fluoride-releasing sealant, Clinpro (3M, ESPE), was used as the positive control. Bacterial colony-forming unit (CFU) counts, metabolic activity tests, field emission-scanning electron microscopy (FE-SEM), and confocal laser scanning microscopy (CLSM) observations were used to evaluate the antibacterial properties of AgBr/BHPVP-modified sealants against Streptococcus mutans before and after five months of aging. The Vickers microhardness, degree of conversion, and microleakage level of the sealants were also investigated. According to the results of CFU counts and metabolic tests, sealants containing AgBr/BHPVP showed better contact-killing bactericidal activity against S. mutans than the two commercial sealants, irrespective of aging conditions (both P < 0.05). The AgBr/BHPVP-modified sealants also showed a significant inhibitory effect on the planktonic S. mutans around the cured sealant surfaces. In addition, the Vickers microhardness, degree of conversion, and microleakage level of the parent material were not damaged by modification with AgBr/BHPVP (P > 0.05). AgBr/BHPVP-modified pit and fissure sealant with a dual bactericidal mechanism is a promising option for the prevention of pit and fissure caries.

Precise sequencing of single protected-DNA fragment molecules for profiling of protein distribution and assembly on DNA

Multiple DNA-interacting protein molecules are often dynamically distributed and/or assembled along a DNA molecule to adapt to their intricate functions temporally. However, analytical technology for measuring such binding behaviours is still missing. Here, we demonstrate the unique capacity of a supernuclease for a highly efficient cutting of the unprotected-DNA segments and with complete preservation of the protein-occluded DNA segments at near single-nucleotide resolution. By exploring this high-resolution cutting, an unprecedented assay that allows a precise sequencing of single protected-DNA fragment molecules (SPDFMS) was developed. As relevant applications, relevant information was gained on the respective distribution/assembly patterns and coordinated displacement of single-stranded DNA-binding protein and recombinase RecA, two model proteins, on DNA. Benefiting from this assay, we also for the first time provide direct measurement of the length of single RecA nucleofilaments, showing the predominant stoichiometry of 5-7 RecA monomers per RecA nucleofilament under physiologically relevant conditions. This innovative assay appears as a promising analytical tool for studying diverse protein-DNA interactions implicated in DNA replication, transcription, recombination, repair, and gene editing.