[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.

[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.

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.

[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.

Mode of induction of platelet-derived extracellular vesicles is a critical determinant of their phenotype and function

Platelet-derived extracellular vesicles (PDEVs) are the most abundant amongst all types of EVs in the circulation. However, the mechanisms leading to PDEVs release, their role in coagulation and phenotypic composition are poorly understood. PDEVs from washed platelets were generated using different stimuli and were characterised using nanoparticle tracking analysis. Procoagulant properties were evaluated by fluorescence flow cytometry and calibrated automated thrombography. EVs from plasma were isolated and concentrated using a novel protocol involving a combination of size exclusion chromatography and differential centrifugation, which produces pure and concentrated EVs. Agonist stimulation enhanced PDEV release, but did not alter the average size of EVs compared to those produced by unstimulated platelets. Agonist stimulation led to lower negatively-charged phospholipid externalization in PDEVs, which was reflected in the lower procoagulant activity compared to those generated without agonist stimulation. Circulating EVs did not have externalized negatively-charged phospholipids. None of the 4 types of EVs presented tissue factor. The mechanism by which PDEV formation is induced is a critical determinant of its phenotype and function. Importantly, we have developed methods to obtain clean, concentrated and functional EVs derived from platelet-free plasma and washed platelets, which can be used to provide novel insight into their biological functions.

Community diversity and abundance of ammonia-oxidizing archaea and bacteria in shrimp pond sediment at different culture stages

AIMS

Ammonia oxidation is a significant process of nitrogen cycles in a lot of ecosystems sediments while there are few studies in shrimp culture pond (SCP) sediments. This paper attempted to explore the community diversity and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in SCP sediments at different culture stages.

METHODS AND RESULTS

We collected SCP sediments and analysed the community diversity and abundance of AOA and bacteria in shrimp pond sediment at different culture stages using the ammonia monooxygenase (amoA) gene with quantitative PCR (qPCR) and 16S rRNA gene sequencing. The AOB-amoA gene abundance was showed higher than AOA-amoA gene abundance in SCP sediments on Day 50 and Day 60 after shrimp larvae introducing into the pond, and the diversity of AOA in SCP sediments was higher than that of AOB. The phylogenetic tree revealed that the most of AOA were the member of Nitrosopumilus and Nitrososphaera, and the majority of AOB sequences were clustered into Nitrosospira, Nitrosomonas clusters 6a and 7. The AOA community has close relationship with total organic carbon (TOC), pH, total phosphorus (TP), nitrate reductase, urease, acid phosphatase and β-glucosidase. The AOB community was related to TOC, C/N and nitrate reductase.

CONCLUSIONS

AOA and AOB play the different ecological roles in SCP sediments at different culture stages.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results suggested that the different community diversity and abundance of AOA and AOB in SCP sediments, which may improve our ecological cognition of shrimp culture stages in SCP ecosystems.

Antimicrobial resistance phenotypes and genotypes of Streptococcus suis isolated from clinically healthy pigs from 2017 to 2019 in Jiangxi Province, China

AIMS

This study aimed to investigate the antimicrobial resistance (AMR) profiles and genotypes of Streptococcus suis from Jiangxi Province, China.

METHODS AND RESULTS

A total of 314 nasal swab samples were collected from clinically healthy pigs, with a positive isolation rate of S. suis of 34·08%. Antimicrobial susceptibility testing showed that more than 80% of the isolates were susceptible to vancomycin, penicillin, minocycline and chloramphenicol. A high frequency of resistance to clindamycin, tetracycline, clarithromycin and erythromycin was observed. All of the isolates were resistant to three or more categories of antimicrobials. The erm(B) and tet(O) served as the most frequent genotypes that contributed to lincosamide, macrolide and tetracycline resistances. A part of macrolide-resistant genotypes could not exhibit specific phenotypes. Finally, integrative and conjugative elements (ICEs) were identified in 28·97% of the isolates.

CONCLUSIONS

The multidrug resistance of S. suis has widely emerged in Jiangxi Province. The most prevalent resistance genes and genotypes were similar to those in other regions or countries. The presence of ICEs is increasing the risk of horizontal transfer of AMR genes.

SIGNIFICANCE AND IMPACT OF THE STUDY

The findings could provide guidance for the rational use of antimicrobial drugs and be helpful for monitoring the AMR information of S. suis in China.

[The role of large-scale testing platform in the prevention and control of the COVID-19 pandemic: an empirical study based on a novel numerical model]

Objective: China adopted an unprecedented province-scale quarantine since January 23rd 2020, after the novel coronavirus (COVID-19) broke out in Wuhan in December 2019. Responding to the challenge of limited testing capacity, large-scale (>20 000 tests per day) standardized and fully-automated laboratory (Huo-Yan) was built as an ad-hoc measure. There is so far no empirical data or mathematical model to reveal the impact of the testing capacity improvement since quarantine. Methods: Based on the suspected case data released by the Health Commission of Hubei Province and the daily testing data of Huo-Yan Laboratory, the impact of detection capabilities on the realization of "clearing" and "clearing the day" of supected cases was simulated by establishing a novel non-linear and competitive compartments differential model. Results: Without the establishment of Huo-Yan, the suspected cases would increase by 47% to 33 700, the corresponding cost of quarantine would be doubled, the turning point of the increment of suspected cases and the achievement of "daily settlement" (all newly discovered suspected cases are diagnosed according to the nucleic acid testing result) would be delayed for a whole week and 11 days. If the Huo-Yan Laboratory could ran at its full capacity, the number of suspected cases could start to decrease at least a week earlier, the peak of suspected cases would be reduced by at least 44%, and the quarantine cost could be reduced by more than 72%. Ideally, if a daily testing capacity of 10 500 tests was achieved immediately after the Hubei lockdown, "daily settlement" for all suspected cases could be achieved. Conclusions: Large-scale, standardized clinical testing platform, with nucleic acid testing, high-throughput sequencing, and immunoprotein assessment capabilities, need to be implemented simultaneously in order to maximize the effect of quarantine and minimize the duration and cost of the quarantine. Such infrastructure, for both common times and emergencies, is of great significance for the early prevention and control of infectious diseases.

Clinical characteristics of non-critically ill patients with novel coronavirus infection (COVID-19) in a Fangcang Hospital

OBJECTIVES

To describe the clinical characteristics of patients in a Fangcang Hospital.

METHODS

Non-critically ill individuals with positive SARS-CoV-2 RT-PCR tests admitted between 7 February and 12 February 2020 to Dongxihu Fangcang Hospital, which was promptly constructed because of the rapid, exponential increase in COVID-19 patients in Wuhan, China, were included; clinical course through to 22 February was recorded.

RESULTS

A total of 1012 non-critically ill individuals with positive SARS-CoV-2 RT-PCR tests were included in the study. Thirty (of 1012, 3.0%) individuals were asymptomatic on admission. During hospitalization, 16 of 30 (53.3%) asymptomatic individuals developed different symptoms. Fourteen of 1012 patients (1.4%) remained asymptomatic from exposure to the end of follow up, with a median duration of 24 days (interquartile range 22-27). Fever (761 of 1012, 75.2%) and cough (531 of 1012, 52.4%) were the most common symptoms. Small patchy opacities (355 of 917, 38.7%) and ground-glass opacities (508 of 917, 55.4%) were common imaging manifestations in chest CT scans. One hundred patients (9.9%) were transferred to designated hospitals due to aggravation of illness. Diarrhoea emerged in 152 of 1012 patients (15.0%). Male, older age, diabetes, cardiovascular diseases, chills, dyspnoea, So2 value of ≤93%, white blood cell counts of >10 × 109/L and large consolidated opacities on CT images were all risk factors for aggravation of illness.

CONCLUSIONS

Non-critically ill individuals had different clinical characteristics from critically ill individuals. Asymptomatic infections only accounted for a small proportion of COVID-19. Although with a low incidence, diarrhoea was observed in patients with COVID-19, indicating the possibility of faecal-oral transmission.