[Analysis of components of proteins from Echinococcus granulosus cyst fluid]

OBJECTIVE

To analyze the components of proteins from Echinococcus granulosus cyst fluid using the shotgun method, and to identify the active components with potential regulatory effects for immune dysregulation diseases.

METHODS

The E. granulosus cyst fluid was collected aseptically from the hepatic cysts of patients with cystic echinococcosis, and characterized by liquid chromatography (LC) tandem mass spectrometry (MS/MS) following digestion with trypsin. The protein data were searched using the software MaxQuant version 1.6.1.0 and the cellular components, molecular functions, and biological processes of the identified proteins were analyzed using the Gene Ontology (GO) method.

RESULTS

The E. granulosus cyst fluid separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) had a relative molecular mass of 25 to 70 kDa. LS-MS/MS analysis identified 37 proteins, including 32 known proteins and 5 unknown proteins. At least 4 proteins were preliminarily found to exhibit potential regulatory effects for immune dysregulation diseases, including antigen B, glutathione-S-transferase (GST), thioredoxin peroxidase (TPX) and malate dehydrogenase (MDH). GO enrichment analysis showed that the identified proteins had 149 molecular functions and were involved in 341 biological processes.

CONCLUSIONS

E. granulosus cyst fluid has a variety of protein components, and four known proteins are preliminarily identified to be associated with immune dysregulation diseases.

[Factors associated with identification of lymph node detected by axillary reverse mapping for breast cancer]

Objective: To investigate the different tracer materials in identifying the axillary reverse mapping(ARM) lymph nodes. Methods: A retrospective analysis of clinical and pathological data of 478 breast cancer female patients(mean age: 50.5±8.0) under axillary lymph node dissection(ALND) with ARM technique was conducted between March 2019 and November 2020 in Wuhan University Zhongnan Hospital. Of the 478 patients, methylene blue was applied in 147 patients, indocyanine green in 119, and indocyanine green plus methylene blue in 212 patients. Wilcoxon rank-sum test, Chi-squire test or Fisher test, and binary logistic regression were carried out to identify the factors associated with identifying ARM lymph nodes. Results: The recognition rates of ARM lymph nodes were 73.5%, 79.0%, and 83.0%(P=0.091), and the recognition rate of ARM lymphatic vessels was 62.6%, 92.4%, 89.6%(P<0.001), respectively. The coincidence rate of ARM lymph node and SLN was 8.1%(12/148), and the metastasis rate was 16.1%(61/378). Supplemental injection of 1 ml of methylene blue or indocyanine green can improve the identification of ARM lymph nodes. The larger BMI and the performance of neoadjuvant therapy were associated with the lower recognition rate of ARM lymph nodes. Neoadjuvant therapy was an independent factor for the identification rate of ARM lymph nodes. Conclusions: Indocyanine green combined with methylene blue can improve the recognition rate of ARM lymph nodes. Obese patients have a lower recognition rate of ARM lymph nodes, and the supplemental injection tracer can be injected to improve the recognition rate. In breast cancer patients whose ARM lymph nodes are not successfully identified during operation, it may be that the ARM lymph nodes are not located in the axilla.

[Analysis on the imported Coronavirus Disease 2019 related cluster epidemic in rural areas of Chengdu]

An epidemiological investigation was carried out on a local cluster of outbreak caused by imported cases of Coronavirus Disease 2019 (COVID-19) in rural areas of Chengdu in December 2020, to find out the source of infection and the chain of transmission. According to Prevention and Control Protocol for COVID-19 (Version 7), field epidemiological investigation was adopted, combined with big data technology, video image investigation, gene sequencing and other methods to carry out investigation into COVID-19 cases and infections source tracing, analyze the epidemiological association, and map the chain of transmission. From December 7 to 17, 2020, 13 local COVID-19 confirmed cases and 1 asymptomatic case were diagnosed in Chengdu, of which 12 cases (85.71%) had a history of residence and activity in the village courtyard of Taiping (TP), Pidu (P) District, Chengdu. From November 8, 2020 to November 28, 2020, a group of inbound people form Nepal were transferred to the designated entry personnel quarantine hotel of P District which was adjacent to the TP village. During quarantine, there were 5 cases who tested positive for COVID-19. Through gene sequencing alignment, genes of local cases and Nepalese imported cases from the same period are homologous, all belong to the lineage of L2.2.3 (B.1.36 according to Pangolin lineage typing method). According to the results of field epidemiological investigation and gene sequencing analysis, the index case was most likely infected by contact with household waste of quarantine site. Under the situation of normalization prevention and control of COVID-19, sentinel monitoring of fever clinics in primary medical institutions is the key to early detection of the epidemic. The multi-department joint epidemiological investigation and the application of gene technology are the core links of the investigation and traceability of modern infectious diseases. The allocation of public health resources in rural areas needs to be strengthened. We need to improve the capacity for early surveillance and early warning of the epidemic in rural areas.

Comprehensive evaluation of genetic variants using chromosomal microarray analysis and exome sequencing in fetuses with congenital heart defect

OBJECTIVE

To evaluate comprehensively, using chromosomal microarray analysis (CMA) and exome sequencing (ES), the prevalence of chromosomal abnormalities and sequence variants in unselected fetuses with congenital heart defect (CHD) and to evaluate the potential diagnostic yields of CMA and ES for different CHD subgroups.

METHODS

This was a study of 360 unselected singleton fetuses with CHD detected by echocardiography, referred to our department for genetic testing between February 2018 and December 2019. We performed CMA, as a routine test for aneuploidy and copy number variations (CNV), and then, in cases without aneuploidy or pathogenic CNV on CMA, we performed ES.

RESULTS

Overall, positive genetic diagnoses were made in 84 (23.3%) fetuses: chromosomal abnormalities were detected by CMA in 60 (16.7%) and sequence variants were detected by ES in a further 24 (6.7%) cases. The detection rate of pathogenic and likely pathogenic genetic variants in fetuses with non-isolated CHD (32/83, 38.6%) was significantly higher than that in fetuses with isolated CHD (52/277, 18.8%) (P < 0.001), this difference being due mainly to the difference in frequency of aneuploidy between the two groups. The prevalence of a genetic defect was highest in fetuses with an atrioventricular septal defect (36.8%), ventricular septal defect with or without atrial septal defect (28.4%), conotruncal defect (22.2%) or right ventricular outflow tract obstruction (20.0%). We also identified two novel missense mutations (c.2447G>C, p.Arg816Pro; c.1171C>T, p.Arg391Cys) and a new phenotype caused by variants in PLD1.

CONCLUSIONS

Chromosomal abnormalities were identified in 16.7% and sequence variants in a further 6.7% of fetuses with CHD. ES should be offered to all pregnant women with a CHD fetus without chromosomal abnormality or pathogenic CNV identified by CMA, regardless of whether the CHD is isolated. © 2020 International Society of Ultrasound in Obstetrics and Gynecology.

[Functional axillary dissection based on lymphatic drainage for breast cancer: a single center randomized clinical trial]

Objective: To evaluate the effectiveness and safety of functional axillary dissection based on lymphatic drainage (FUND) in decreasing breast cancer-related lymphedema (BCRL) events. Methods: A total of 168 eligible patients in Zhongnan Hospital of Wuhan University from July 2018 to February 2019 were randomly assigned to the FUND group or axillary lymph node dissection (ALND) group using random number table generated by SPSS. In the FUND group, methylene blue (MB) was adopted to reveal the sentinel lymph node (SLN) for all patients; 0.1 ml MB was injected into the SLNs before resection to reveal the efferent lymphatic channels and subsequent-echelon lymph node. The blue-stained lymphatic channels were mapped by bluntly dissecting along the lymphatic drainage channels from the breast to the axilla. Then, the SLNs were removed and pathologically analyzed by immediate frozen sectioning (FS); if the SLNs were positive, the blue-stained bALNs in breast lymphatic level (BLL) Ⅱ were removed and sent for immediate FS; if the blue-stained ALNs in BLL Ⅱ were confirmed negative, the tissues in BLL Ⅱ were removed'en bloc'. Clinicopathologic information for all the patients in the two groups were collected. The fixed-point circumference volume measurement method and the Norman questionnaire scoring method were used to evaluate the arm lymphedema between the two groups. Clinicopathological characteristics, incidences of arm lymphedema, locoregional recurrence, and distant metastasis between the two groups were compared. Results: The mean age were (50.3±8.0) in the FUND group and (51.1±9.0) in the ALND group. Seventy-four cases (88.1%) in the FUND group successfully underwent FUND surgery, and patients whose breast lymphatics failed to be stained blue underwent standard ALND. There was no statistically significant difference in terms of age, BMI, histological types, surgical approaches and adjunct therapy between the FUND group (n=74) and ALND group (n=84) (P>0.05). The average operation time of the FUND group and the stand ALND group were (169±15) and (123±12) min respectively (range: 145-198, 103-146 min) (P<0.001), and the number of lymph nodes removed [M (Q₁, Q₃)] were 8.3 (6, 15) and 12.9 (7, 18) (P=0.019). The cumulative BCRL rate, within a median follow-up of 24 months and 23 months respectively for FUND and ALND group, were 10.8% (8/74) vs 23.8% (20/84) (P=0.033) measured by fixed-point circumference volume measurement method, and was 12.2% (9/74) vs 27.4% (23/84) by Norman questionnaire (P=0.018). There were no local regional recurrence events during the follow-up period between the two groups. Conclusion: For breast cancer patients with clinically node-positive axilla or positive SLN, FUND based on lymphatic drainage was a less radical axillary surgery, with which eliminating the risk of BCRL might be achieved.

[SHOX2 promotes migration, invasion and stemness of bladder cancer cells in vitro]

OBJECTIVE

To explore the role of human short stature homeobox 2 (SHOX2) in regulating the migration, invasion and stemness of human bladder cancer cells.

METHODS

We analyzed SHOX2 gene expression in bladder cancer and adjacent tissues based on TCGA database. Univariate survival analysis of SHOX2 gene expression in TCGA-BLCA data was performed using GEPIA. The probable function of SHOX2 was predicted using GSEA. Human bladder cancer T24 cell models of SHOX2 knockdown or overexpression were assessed for changes in migration and invasion abilities using wound healing assay and Transwell assay, and their cancer stem cell-like characteristics were evaluated using tumorsphere formation assay and colony formation assay. Western blotting was used to detect the expressions of epithelial mesenchymal transition (EMT) markers Ecadherin and vimentin and the TGF-β signaling network component TβR-I in the cells.

RESULTS

SHOX2 expression was significantly higher in bladder cancer tissues than in the adjacent tissues (P < 0.05), especially in paired tissue specimens (P < 0.01), and was negatively correlated with the overall survival of the patients (P < 0.05). SHOX2 gene expression was correlated positively with EMT-related (P < 0.05) and stemness-related gene signatures (P < 0.01). In T24 cells, SHOX2 knockdown significantly suppressed cell migration and invasion, which was significantly enhanced by SHOX2 overexpression (P < 0.01). The cancer stem cell-like characteristics of T24 cells was repressed by SHOX2 knockdown but significantly enhanced by SHOX2 overexpression (P < 0.01). SHOX2 knockdown induced morphological changes of the cells into epithelioid cells, whereas SHOX2 overexpression induced a mesenchymal morphology of the cells. SHOX2 knockdown increased E-cadherin expression and decreased vimentin and TβR-I expression, while SHOX2 overexpression increased the expressions of vimentin and TβR-I in the cells.

CONCLUSION

SHOX2 promotes the migration, invasion and stemness of human bladder cancer cells possibly by regulating EMT via the TGF-β signaling pathway.

A magnetic resonance imaging study on the temporomandibular joint disc-condyle relationship in young asymptomatic adults

The aim of this study was to assess the temporomandibular joint (TMJ) disc-condyle relationship in asymptomatic young adults. Ninety-three volunteers aged 19-23 years without temporomandibular disorder (TMD) symptoms underwent TMJ magnetic resonance imaging (MRI). The condylar centre and apex methods were used to measure and analyse the position of the disc in the oblique sagittal plane, and the reliability of the two methods was compared by calculating the intra-class correlation coefficient (ICC). Furthermore, 18 of the volunteers were randomly selected for three-dimensional (3D) reconstruction of the TMJ structure and the disc-condyle relationship. The 3D TMJ structure was established by semi-automatic segmentation of the condyle and articular disc in ITK-SNAP software; the condylar apex method was then performed. It was found that only 33.3% of the posterior edge of the articular discs were located in the normal 12 o'clock position with respect to the condyle. Moreover, this study suggests that the condylar centre method lacks accuracy when compared to the condylar apex method in regard to the measurement of the TMJ disc-condyle relationship (0 < ICC_cen < ICC_apex < 1). The position of the articular disc (left and right) was more forward in young women when compared to young men. However, there was no significant difference in the TMJ disc-condyle position between the left and right sides in the same individual, although the two joint discs in the same individual were not completely symmetrical.

[Exendin-4 promotes autophagy to relieve lipid deposition in a NAFLD cell model by activating AKT/mTOR signaling pathway]

OBJECTIVE

To investigate the effect of exendin-4 on lipid deposition in hepatocytes and explore its possible mechanism for treatment of nonalcoholic fatty liver disease (NAFLD).

METHODS

Human normal hepatocyte line LO2 and hepatoma cell line HepG2 were treated with palmitic acid (PA) to mimic hepatocyte steatosis or with combined treatments with PA+exendin-4 or PA+exendin-4+3BDO. Lipid deposition and proliferation of the two cell lines following treatment with PA or PA+exendin-4 were detected using Oil Red O staining and CCK8 assay, and the expression of p-mTOR, m-TOR, p-AKT, AKT and autophagy-related proteins LC3-Ⅰ/Ⅱ and p62 were detected with Western blotting; the expression of GLP-1R was detected with both Western blotting and immunofluorescence assay. The expression of LC3-Ⅰ/Ⅱ and p62 in the cells following treatment with PA+exendin-4 and PA+exendin-4+3BDO was detected with Western blotting.

RESULTS

Lipid deposition in the two cell lines increased significantly after PA treatment, but was alleviated by co-treatment with exendin-4. PA treatment significantly inhibited the proliferation of the two cell lines (P < 0.01), and this inhibitory effect was obviously attenuated by exendin-4 (P < 0.05). Immunofluorescence assay showed that both LO2 and HepG2 cells expressed GLP-1R. The expression of p-mTOR was significantly lower and that of p-AKT was higher in cells treated with PA+exendin-4 than in PA-treated cells. Exendin-4 also down-regulated the autophagy-associated protein p62 and up-regulated the expression of LC3-Ⅱ in PA-treated cells, and this effect was obviously reversed by 3BDO.

CONCLUSION

Exendin-4 may activate the AKT-mTOR signal pathway to promote autophagy via its direct action on GLP-1R. Exendin-4 can also alleviate lipid deposition and promote proliferation of PA-treated hepatocytes, suggesting its important role in PA-induced lipid deposition in hepatocytes.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

The significance of urgent ultrasound scan for shoulder dislocation in patients above the age of 40: A prospective British Elbow and Shoulder Society pathway implementation study

BACKGROUND

The highlight of the British Elbow and Shoulder Society pathway for the management of traumatic anterior shoulder instability is early imaging in patients aged over 40 years to assess rotator cuff integrity and early repair, if indicated to optimise function. The senior author set up a protocol in our institute to streamline the diagnostic process for this cohort of patients. This was a retrospective analysis from a prospectively collected database to highlight the importance of early specialist imaging.

METHODS

Our protocol is to perform urgent ultrasound scans for all suitable patients above 40 years after first-time traumatic shoulder dislocation. Demographics, associated injuries, ultrasound scan results, operations and functional outcomes were collated.

RESULTS

One year following the introduction of our protocol, 40 patients with a mean age of 67 (range, 42-89; SD = 13.1) had ultrasound. The incidence of full-thickness rotator cuff tears was 57.5% (n = 23). Eleven patients with confirmed full-thickness rotator cuff tears underwent surgery. The mean age of surgical patients was significantly younger than the non-surgical group (p = 0.004).

DISCUSSION

The use of early diagnostic imaging demonstrated a high incidence of full-thickness rotator cuff tears in this cohort of patients. This allowed early surgical repair to optimise function.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[Clinical effects of anterolateral thigh perforator flap with sensory nerves in repairing the plantar skin and soft tissue defects]

Objective: To explore the clinical effects of anterolateral thigh perforator flap with sensory nerves in repairing the plantar skin and soft tissue defects. Methods: From January 2016 to March 2019, 13 male patients with plantar skin and soft tissue defects were admitted to the Department of Foot and Ankle Surgery of Ruihua Affiliated Hospital of Soochow University, aged 27 to 73 years. The retrospective cohort study was conducted. The wounds of 4 patients underwent 2 times of debridement. The wounds of 9 patients underwent 1 time of debridement and 1 or 2 time(s) of vacuum sealing drainage. Then all the wounds of patients were repaired with flaps when the wounds were clean and dry with no purulent exudation and were negative in secretion culture. The wound areas of this group of patients after wound debridement were 13.0 cm×5.5 cm to 36.0 cm×10.5 cm, and the wounds were repaired with anterolateral thigh perforator flaps with sensory nerves with area of 14 cm×6 cm to 37 cm×11 cm. The wound of 1 patient was repaired with a bilobed flap. The oblique or descending branch of the lateral circumflex femoral artery and its accompanying vein in the flap were anastomosed with the posterior tibial artery and its accompanying vein or the medial plantar artery and its accompanying vein in recipient sites. The lateral femoral cutaneous nerve in the flap was anastomosed with the recipient saphenous nerve or medial plantar cutaneous nerve. The donor sites were directly sutured. The survival of flaps and the healing of wounds in the donor and recipient areas were recorded, and the ulcers of the plantar repaired flap were followed up for 3 months after operation. The sensory function of the flap was evaluated by the sensory evaluation standard of British Medical Research Council (BMRC), and the ankle and foot function score system of American Orthopedic Foot and Ankle Society (AOFAS) was used for comprehensive functional evaluation at the last follow-up. Results: All the 14 flaps in 13 cases survived, and venous crisis occurred in two cases and the flaps survived smoothly after the venous re-anastomosis. One patient developed deep tissue infection after being discharged and was healed after secondary debridement. The donor and recipient areas of the remaining patients healed well. The patients were followed up for 6 to 18 months, the shape of flaps was slightly bloated in 5 patients, and the shape and texture of flaps in the other 8 patients were good. Six patients had ulcers in flaps at 3 months of follow-up after operation, which were healed after stopping weight-bearing activities. At the last follow-up, little linear scar hyperplasia could be seen in the donor site of patients; the BMRC sensory function evaluation results were S₁ grade in 4 cases, S₂ grade in 7 cases, and S₃ grade in 2 cases; the AOFAS scores were excellent in 3 cases, good in 7 cases, fair in 2 cases, and poor in 1 case. Conclusions: The anterolateral thigh perforator flaps with sensory nerves can repair the plantar skin and soft tissue defects with the donor sites directly sutured and good shape of flaps, which provide a good treatment method for the recovery of plantar proprioceptive sensation and weight-bearing function.

Association between serum estradiol levels prior to progesterone administration in artificial frozen-thawed blastocyst transfer cycles and live birth rate: a retrospective study

OBJECTIVE

To study whether serum estradiol (E2) levels prior to progesterone administration in the artificial endometrial preparation (AEP) of frozen-thawed blastocyst transfer affect the live birth rate.

DESIGN

Retrospective cohort study.

SETTING

Tertiary-care academic medical centre.

POPULATION

A total of 3857 frozen-thawed blastocyst transfer cycles were divided into three groups: <200 pg/ml (n = 1676); 200-399 pg/ml (n = 1296); and ≥400 pg/ml (n = 885), based on the 25th (182.3 pg/ml) and 75th percentile (390.2 pg/ml) of serum E2 level prior to progesterone administration.

METHODS

Univariable and multivariable logistic regression analysis was performed.

MAIN OUTCOME MEASURES

The primary outcome of the study was the live birth rate and the secondary outcomes included clinical pregnancy rate, pregnancy loss rate, neonatal birthweight, Z-score, and small for gestational age (SGA).

RESULTS

Compared with the reference group, accounting for major covariates, the live birth rate significantly decreased in the '≥400 pg/ml' group (adjusted OR 0.71, 95% CI 0.59-0.85). Compared with the reference group, there was an association between the E2 level in the '≥400 pg/ml' group and a decrease in the clinical pregnancy rate (adjusted OR 0.74, 95% CI 0.61-0.89). Compared with the reference group, the pregnancy loss rate significantly increased in the '≥400 pg/ml' group (adjusted OR 1.45, 95% CI 1.08-1.93). The E2 levels did not affect neonatal birthweight, Z-score, and SGA among singletons.

CONCLUSIONS

High serum E2 levels prior to progesterone administration in AEP are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

TWEETABLE ABSTRACT

High serum E2 levels prior to progesterone administration in artificial FET are associated with a decreased live birth rate after frozen-thawed blastocyst transfer.

Extending the Classical Continuum Theory to Describe Water Flow through Two-Dimensional Nanopores

Water flow through two-dimensional nanopores has attracted significant attention owing to the promising water purification technology based on atomically thick membranes. However, the theoretical description of water flow in nanopores based on the classical continuum theory is very challenging owing to the pronounced entrance/exit effects. Here, we extend the classical Hagen-Poiseuille equation for describing the relationship between flow rate and pressure loss in laminar tube flow to two-dimensional nanopores. A totally theoretical model is established by appropriately considering the velocity slip on pore surfaces both in the friction pressure loss and entrance/exit pressure loss. Based on molecular dynamics simulations of water flow through graphene nanopores, it is shown that the model can not only well predict the overall flow rate but also give a good estimation of the velocity profiles. As the pore radius and length increase, the model can reduce to the equations applicable to the fluid flow in infinitely/finitely long nanotubes, thin orifices, and macroscale tubes, showing an accurate prediction of the existing experimental and simulation data of the water flow through nanotubes and nanopores in the literature. Namely, the presented model is a unified model that can uniformly describe the fluid flow from nanoscales to macroscales by modifying the classical continuum theory.

[Clinical effects of bilateral overlength anterolateral femoral perforator flaps connected in series or parallel in repairing large area of wounds in limbs]

Objective: To explore the clinical effects of bilateral overlength anterolateral femoral perforator flaps connected in series or parallel in repairing large area of wounds in limbs. Methods: From January 2017 to July 2019, 9 patients with large area of skin and soft tissue defects in limbs were admitted to the Departments of Hand Surgery and Foot and Ankle Surgery of Ruihua Affiliated Hospital of Soochow University, including 8 males and 1 female, aged 36 to 63 years. The retrospective cohort study was conducted. The wound areas of patients after debridement were 20 cm×15 cm to 30 cm×25 cm, and the wounds were repaired with bilateral overlength anterolateral femoral perforator flaps. One main artery defect in the receiving area of 4 patients was repaired with bilateral flaps connected in series. Two main artery defects in the receiving area of 5 patients were repaired with bilateral flaps connected in parallel. A total of 18 flaps were excised, and the area of a single flap ranged from 20 cm×8 cm to 46 cm×9 cm. The donor sites of 17 flaps were sutured directly, and the donor site of 1 flap was repaired with free full-thickness skin graft from hypogastrium. Harvesting time of flaps, survival condition of flaps after surgery, and wound healing time, and flap observation, two-point discrimination distance of flaps, functional recovery of joint and appearance of recipient site, and recovery of donor site during follow-up were recorded. Results: In this group of 9 patients, the flap harvesting time was 1.0 to 4.5 hours, and all the 18 flaps survived. The wound healing time of recipient site was 18 to 72 days after flap transplantation. They were followed up for 6 to 34 months. The shape of the recipient site was satisfactory, with no deep tissue infection such as osteomyelitis. Four flaps in 2 patients were bloated and were thinned in 6 months after operation; 4 flaps in 2 patients had skin pigmentation on the edge of the flap; the flap of one patient was scalded but healed by dressing change, with patchy scar being observed during follow-up. The rest of the flaps were soft, elastic, and painless with good blood supply. All the flaps restored with protective sensation, with only one point in two-point discrimination. Only linear scars remained in the donor sites of 17 flaps. All the limbs had good blood supply in the distal end of donor sites, and no restriction occurred in range of motion of knee joint and quadriceps muscle strength. Conclusions: The bilateral overlength anterolateral femoral perforator flaps connected in series or parallel have constant anatomy, reliable blood supply, and flexible combination. It is an ideal surgical method for repairing large area of skin and soft tissue defects in limbs at one time.

Prx II reduces oxidative stress and cell senescence in chondrocytes by activating the p16-CDK4/6-pRb-E2F signaling pathway

OBJECTIVE

Osteoarthritis (OA) is a common clinical degenerative disease and has a high incidence in the elderly. The purpose of this study was to explore the anti-oxidative stress and anti-aging effects of Peroxiredoxin II (Prx II) on articular chondrocytes, as well as its molecular mechanism.

MATERIALS AND METHODS

Articular cartilage tissues and culture human articular chondrocytes were selected. By constructing Prx II overexpressing lentivirus, the effects of Prx II on oxidative stress and cell senescence in chondrocytes were studied. Besides, the p16 overexpression lentivirus was constructed to investigate the effect of Prx II on the p16-CDK4/6-pRb-E2F signaling pathway (p16 signaling pathway).

RESULTS

Articular cartilage tissues in patients with OA and IL-1β-induced chondrocytes expressed lower Prx II and had higher p16 signaling pathway activity. The overexpression of Prx II significantly increased the expression of SOD1 and SOD2 and decreased the expression of β-gal and P53/P21, indicating that Prx II can reduce the oxidative stress and senescence level of chondrocytes. Moreover, the overexpression of Prx II increased the expression of p16 signaling pathway-related molecules and the activation of the p16 signaling pathway attenuated the anti-oxidative stress and anti-aging effects of Prx II.

CONCLUSIONS

Prx II can inhibit the p16 signaling pathway in chondrocytes to reduce the level of aging in chondrocytes, thereby reducing the level of oxidative stress in chondrocytes, and ultimately inhibiting the progression of OA.

Theoretical description of molecular permeation via surface diffusion through graphene nanopores

We establish a theoretical model to describe the surface molecular permeation through two-dimensional graphene nanopores based on the surface diffusion equation and Fick's law. The model is established by considering molecular adsorption and desorption from the surface adsorption layer and the molecular diffusion and concentration gradient on the graphene surface. By comparing with the surface flux obtained from molecular dynamics simulations, it is shown that the model can predict well the overall permeation flux especially for strongly adsorbed molecules (i.e. CO₂ and H₂S) on graphene surfaces. Although good agreement between the theoretical and simulated density distribution is hard to achieve owing to the large uncertainty in the calculation of surface diffusion coefficients based on the Einstein equation, the model itself is very competent to describe the surface molecular permeation both from the aspects of the overall permeation flux and detailed density distribution. This model is believed to supplement the theoretical description of molecular permeation through graphene nanopores and provide a good reference for the description of mass transport through two-dimensional porous materials.

Protein-protein interaction network and potential drug target candidates of Streptococcus suis

AIMS

This study aimed to explore potential drug targets of Streptococcus suis at the system level.

METHODS AND RESULTS

A homologous protein mapping method was used in the construction of a protein-protein interaction (PPI) network of S. suis, which presented 1147 non-redundant interaction pairs among 286 proteins. The parameters of PPI networks were calculated and showed scale-free network properties. In all, 41 possibly essential proteins identified from 47 highly connected proteins were selected as potential drug target candidates. Of these proteins, 30 were already regarded as drug targets in other bacterial species. Six transporters with high connections to other functional proteins were identified as probably not essential but important functional proteins. Afterward, the subnetwork centred with cell division protein FtsZ was used in confirming the PPI network through bacterial two-hybrid analysis.

CONCLUSIONS

The predicted PPI network covers 13·04% of the proteome in S. suis. The selected 41 potential drug target candidates are conserved between S. suis and several model bacteria.

SIGNIFICANCE AND IMPACT OF THE STUDY

The predictions included proteins known to be drug targets, and a verifying experiment confirmed the reliability of predicted interactions. This work is the first to present systematic computational PPI data for S. suis and provides potential drug targets, which are valuable in exploring novel anti-streptococcus drugs.

Wall friction should be decoupled from fluid viscosity for the prediction of nanoscale flow

The accurate determination of fluid viscosity based on the microscopic information of molecules is very crucial for the prediction of nanoscale flow. Despite the challenge of this problem, researchers have done a lot of meaningful work and developed several distinctive methods. However, one of the common approaches to calculate the fluid viscosity is using the Green-Kubo formula by considering all the fluid molecules in nanospace, inevitably causing the involvement of the frictional interaction between fluid and the wall into the fluid viscosity. This practice is certainly not appropriate because viscosity is essentially related only to the interactions among fluid molecules. Here, we clarify that the wall friction should be decoupled from fluid viscosity by distinguishing the frictional region and the viscous region for the accurate prediction of nanoscale flow. By comparing the fluid viscosities calculated from the Green-Kubo formula in the whole region and viscous region and the viscosity obtained from the velocity profile through the Hagen-Poiseuille equation, it is found that only the calculated viscosity in the viscous region agrees well with the viscosity from the velocity profile. To demonstrate the applicability of this clarification, the Lennard-Jones fluid and water confined between Lennard-Jones, graphene, and silica walls, even with different fluid-wall interactions, are extensively tested. This work clearly defines the viscosity of fluids at nanoscales from the inherent nature of physics, aiming at the accurate prediction of nanoscale flow from the classical continuum hydrodynamic theory.

[Analysis of pregnancy outcome after fertility-preserving treatment among women with atypical endometrial hyperplasia or endometrial carcinoma]

Objective: To analyze the pregnancy outcome, influencing factors and recurrence of fertility-preserving therapy for women with atypical endometrial hyperplasia (AEH) or endometrial carcinoma (EC). Methods: The multi-center retrospective study included 107 women with AEH or EC for fertility-preserving therapy in 10 hospitals from January 1st, 2009 to December 31st, 2018. The clinical pregnancy rate, live birth rate and recurrence of 66 patients with urgent child-bearing requirements after fertility-preserving treatment were analyzed. Results: (1) Among the 66 AEH and EC women with urgent child bearing requirements, 24 women chose spontaneous pregnancy, the clinical pregnancy rate was 54.2% (13/24) and the live birth rate was 41.7% (10/24), the median time from fertility-preserving therapy withdrawal to clinical pregnancy was 5.5 months. Forty-two women chose assisted reproductive technology (ART), the clinical pregnancy rate was 59.5% (25/42) and the live birth rate was 35.7% (15/42), the median time from fertility-preserving therapy withdrawal to clinical pregnancy was 19.5 months. The time from fertility-preserving therapy withdrawal to pregnancy in women receiving ART was significantly longer than that in women with spontaneous pregnancy (P=0.048). (2) Age and intrauterine adhesions were independent factors affecting the clinical pregnancy rate (P<0.05). (3) Among 107 patients with AEH or EC, the recurrence rate was 27.1% (29/107). Among the 42 cases who chose ART, 9 of them recurred before ART treatment, who received the fertility-preserving therapy again and then ART treatment, 8 women got clinical pregnancy,5 of them delivered at least a live birth. Conclusions: Women with AEH or EC could achieved satisfactory clinical pregnancy rate and live birth rate after fertility-preserving therapy. Age and intrauterine adhesions are independent factors affecting clinical pregnancy rate. The women with recurrent AEH or EC could be treated with fertility-preserving therapy again and get a satisfactory pregnancy outcome.

Hierarchical thermal transport in nanoconfined water

The structure of nanoconfined fluids is particularly non-uniform owing to the wall interaction, resulting in the distinctive characteristic of thermal transport compared to bulk fluids. We present the molecular simulations on the thermal transport of water confined in nanochannels with a major investigation of its spatial distribution under the effects of wall interaction. The results show that the thermal conductivity of nanoconfined water is inhomogeneous and its layered distribution is very similar to the density profile. The layered thermal conductivity is the coupling result of inhomogeneous density and energy distributions that are generally diametrical, and their contributions to the thermal conductivity compensate with each other. However, the accumulative effect of water molecules is really dominating, resulting in a high thermal conductivity in the high-density layers with the low-energy molecules, and vice versa. Moreover, it is found that the adsorptive and repulsive interactions from solid walls have different roles in the hierarchical thermal transport in nanoconfined water. The adsorptive interaction is only responsible for the layered distribution of thermal conductivity, while the repulsive interaction is responsible for the overall thermal conductivity; accordingly, the thermal conductivity is independent of the strength of water-solid interactions. The identified hierarchical thermal transport in nanoconfined water and its underlying mechanisms have a great significance for the understanding of nanoscale thermal transport and even the mass and energy transport of nanoconfined fluids.