[Clinical analysis of 18 children with aggressive mature B-cell lymphoma after liver transplantation]

Objective: To summarize the clinical characteristics, prognostic factors and treatment outcomes of childhood aggressive mature B-cell lymphoma after liver transplantation. Methods: This retrospective study included 18 children with newly diagnosed aggressive mature B-cell lymphoma after liver transplantation and treated from June 2018 to June 2022 in the Department of Hematology and Oncology of Shanghai Children's Medical Center, Shanghai Jiao Tong University School of Medicine. Clinical characteristics, treatment and outcomes of patients at last evaluation were analyzed. Overall survival (OS) and event free survival (EFS) rates were calculated by Kaplan-Meier method and Log-Rank analysis was performed to find factors of poor prognosis. Results: Among all 18 patients, there were 6 males and 12 females, and the age of onset was 40 (35, 54) months. The interval from transplant to tumor diagnosis was 21 (17, 35) months and 5 patients had early onset disease (<1 year since transplant). Seventeen patients had abdominal lesions. Diarrhea, vomiting and abdominal masses were the main clinical manifestations. All patients were Epstein-Barr virus (EBV) related posttransplant lymphoproliferative disorders (PTLD). One patient received individualized therapy due to critical sick at diagnosis, and the remaining 17 patients received CP (cyclophosphamide, methylprednisolone plus rituximab) and/or modified EPOCH (prednisone, etoposide, doxorubicin, vincristine, cyclophosphamide plus rituximab) regimens. Of all 18 patients, 15 cases got complete response, 2 cases got partial response, 1 patient died of severe infection. The 2-year OS and EFS rates of 18 patients were (94±5)% and (83±8)%, respectively. None of age, gender or early onset disease had effect on OS and EFS rates in univariate analysis (all P>0.05). Conclusions: The symptoms of PTLD were atypical. Close surveillance of EBV-DNA for patients after liver transplantation was crucial to early stage PTLD diagnosis. CP or modified EPOCH regimen was efficient for pediatric patients with aggressive mature B cell lymphoma after liver transplantation.

[Intraoperative optical coherence tomography guided precise corneal suture in the treatment of acute keratoconus]

Objective: This study aimed to observe the clinical efficacy of precise suturing of posterior elastic layer fissures guided by intraoperative optical coherence tomography (OCT) in conjunction with anterior chamber puncture and drainage, and corneal thermokeratoplasty for the treatment of severe acute edematous keratoconus. Methods: Non-randomized controlled trial. Data were collected for a study involving 31 cases of acute edematous keratoconus patients who underwent surgical treatment at the Shandong Eye Hospital between June 2017 and July 2021. Among them, there were 30 male and 1 female patients, with an age range of 11 to 32 years and a mean age of (19.80±5.80) years. Eighteen patients in the study group underwent precise suturing of posterior elastic layer fissures guided by intraoperative OCT, in combination with anterior chamber puncture and drainage, and corneal thermokeratoplasty. Thirteen patients in the control group did not undergo suturing. Preoperative visual acuity, corneal edema diameter, corneal thickness, and posterior elastic layer fissure length were collected. Evaluation was performed using slit lamp microscopy, anterior segment OCT, and other methods to assess the time of initial postoperative corneal edema resolution and closure of the posterior elastic layer fissure. Deep lamellar keratoplasty was performed 2 to 4 weeks after edema resolution, and the corneal bed scar repair and visual acuity of the two groups were compared. Results: In the suturing group, the corneas of all 18 patients were accurately sutured to the deep stromal layer near the posterior elastic layer. The time for corneal edema resolution was 2.50 (1.00, 6.25) days in the suturing group and 7.00 (6.00, 10.50) days in the control group. The fissure healing time was 7.50 (7.00, 12.00) days in the suturing group and 14.00 (9.00, 14.00) days in the control group. The differences were statistically significant (all P<0.05). After 2 weeks, the central corneal thickness decreased to (529.80±174.50) μm in the suturing group and (612.00±205.12) μm in the control group. The suturing group showed accurate corneal suturing to the deep stromal layer near the posterior elastic layer, resulting in central corneal flattening, closure of voids in the stroma, and a significant decrease in corneal thickness. All 18 patients in the suturing group successfully completed deep lamellar keratoplasty, with 6 cases (6/18) experiencing mild graft bed leakage during surgery but without affecting the deep lamellar keratoplasty. One year postoperatively, the visual acuity (logarithm of the minimum resolution angle) was 0.23±0.12 in the suturing group and 0.33±0.11 in the control group, with a statistically significant difference (P<0.05). Conclusions: In the treatment of severe acute edematous keratoconus, precise suturing of posterior elastic layer fissures guided by intraoperative OCT, in conjunction with anterior chamber puncture and drainage, and corneal thermokeratoplasty, can rapidly alleviate corneal edema and promote the healing of posterior elastic layer fissures. This approach achieves better visual outcomes for subsequent lamellar keratoplasty surgeries. The use of intraoperative OCT guidance allows accurate positioning of the posterior elastic layer fissure in terms of location, direction, and depth of corneal stromal voids, thereby assisting surgeons in precise suturing.

SARS-CoV-2 lineage assignments using phylogenetic placement/UShER are superior to pangoLEARN machine-learning method

With the rapid spread and evolution of SARS-CoV-2, the ability to monitor its transmission and distinguish among viral lineages is critical for pandemic response efforts. The most commonly used software for the lineage assignment of newly isolated SARS-CoV-2 genomes is pangolin, which offers two methods of assignment, pangoLEARN and pUShER. PangoLEARN rapidly assigns lineages using a machine-learning algorithm, while pUShER performs a phylogenetic placement to identify the lineage corresponding to a newly sequenced genome. In a preliminary study, we observed that pangoLEARN (decision tree model), while substantially faster than pUShER, offered less consistency across different versions of pangolin v3. Here, we expand upon this analysis to include v3 and v4 of pangolin, which moved the default algorithm for lineage assignment from pangoLEARN in v3 to pUShER in v4, and perform a thorough analysis confirming that pUShER is not only more stable across versions but also more accurate. Our findings suggest that future lineage assignment algorithms for various pathogens should consider the value of phylogenetic placement.

Experiences of baccalaureate nursing students in preceptorship during the COVID-19 pandemic: a systematic review protocol

OBJECTIVE

The objective of this review is to appraise and synthesize current evidence of the clinical experiences of baccalaureate nursing students in preceptorship during the COVID-19 pandemic.

INTRODUCTION

Nursing education programs support quality clinical practice learning experiences, which are essential for preparing students for both the current and future workforce. The COVID-19 pandemic has drastically changed the health care system and, previous estimates of the global shortage of nurses have now almost doubled. Understanding nursing students' clinical experiences during the pandemic can assist with identifying the needs of the future workforce. Nursing students complete the final practicum, also known as the last clinical, internship, or preceptorship, before they are eligible to apply for licensure. This review seeks to explore these pre-transitional, unprecedented preceptorship experiences during COVID-19 to better understand how to prepare pre-licensure nurses for the altered workforce.

INCLUSION CRITERIA

This review will include qualitative studies that address the clinical experiences of undergraduate nursing students in preceptorship during the COVID-19 pandemic from 2020 until the present.

METHODS

The databases to be searched will include CINAHL, MEDLINE, ERIC, Google Scholar, and Embase. Reference lists of included studies will be reviewed to identify additional studies. Gray literature will be searched for via ProQuest Dissertations and Theses, Google, and GreyNet International. Unpublished studies will be searched for on websites, including those of national associations of nursing. Study selection, critical appraisal, data extraction, and data synthesis will be performed independently by 2 reviewers. The findings will be collated using meta-aggregation to produce comprehensive synthesized findings and a ConQual Summary of Findings.

REVIEW REGISTRATION

PROSPERO CRD42022328303.

[Application of intraoperative optical coherence tomography in deep lamellar keratoplasty]

Objective: To evaluate the clinical application value of intraoperative optical coherence tomography (iOCT) in deep anterior lamellar keratoplasty (DALK) using the big-bubble technique to bare Descemet's membrane. Methods: Retrospective case series. Clinical data of 92 patients (92 eyes) with monocular stromal corneal diseases who underwent big-bubble DALK in the Eye Hospital of Shandong First Medical University from January 2020 to August 2021 were collected. There were 53 males and 39 females. The average age was (53.2±16.0) years old. All patients underwent iOCT scanning to determine the location and depth of the injection needle after initial removal of the corneal lesion, to observe the integrity of the recipient bed, Descemet's membrane, after complete lesion removal, and to observe the adhesion between the corneal graft and the recipient bed and check folds on the recipient bed after suturing of the corneal graft. The intraoperative perforation of Descemet's membrane, postoperative thickness of the cornea and the recipient bed, visual acuity, and corneal astigmatism were recorded. Results: By iOCT, the thickness of the recipient bed was found to be about 1/2 of the corneal thickness and relatively uniform in all directions in 62 eyes (67.4%), so the sterile air was injected from the center of the recipient bed to separate it from the stromal layer. In 30 eyes (32.6%) with an uneven thickness of the recipient bed, the sterile air was injected from the paracentral area of the recipient bed. Under the guidance of iOCT scanning, 89 eyes (96.7%) did not experience any perforation of Descemet's membrane during surgery. The Descemet's membrane folds in the central 5-mm area of the recipient bed was observed and flattened in 20 eyes with the assistance of iOCT scanning. The postoperative corneal thickness was (578.95±108.26) μm, and the recipient bed thickness was (36.06±23.11) μm. The best corrected visual acuity of all patients at 6 months after surgery was 0.57±0.25 logMAR, which was significantly better than that before surgery (1.61±1.27 logMAR; P<0.001). The average corneal astigmatism at 6 months after surgery was (2.72±2.44) diopters. Conclusions: The application of iOCT scanning in DALK surgery assisted by the big-bubble method can provide safe guidance for surgeons to adopt correct surgical procedures, decrease the risk of Descemet's membrane perforation, reduce the recipient bed folds, and facilitate corneal interlayer adhesion, thereby improving the visual prognosis.

New methods for estimating the total wing area of birds

Dispersal is a fundamental process in evolution and ecology. Due to the predominant role of flight in bird movement, their dispersal capabilities can be estimated from their flight morphology. Most predictors of flight efficiency require an estimate of the total wing area, but the existing methods for estimating wing area are multi-stepped and prone to compounding error. Here, we validated a new method for estimating the total wing area that requires only the measurement of the wingspan plus two measurements from the folded wings of study skin specimens: wing length and wing width. We demonstrate that the new folded-wing method estimates total wing area with high precision across a variety of avian groups and wing shapes. In addition, the new method performs as well as the old method when used to estimate natal dispersal distances of North American birds. The folded-wing method will allow for estimates of the total wing to be readily obtained from thousands of specimens in ornithological collections, thus providing critical information for studies of flight and dispersal in birds.

[Analysis of 42 cases of childhood superior vena cava syndrome associated with mediastinal malignancy]

Objective: To summarize the clinical features, management and outcome of superior vena cava syndrome (SVCS) associated with mediastinal malignancy in children. Methods: Clinical data of 42 children of SVSC associated with mediastinal malignancy in Shanghai Children's Medical Center from January 2015 to December 2021 were collected and analyzed retrospectively. The clinical manifestations, pathological diagnosis, disease diagnosis process, and prognosis were summarized. Results: Among 42 children of SVCS associated with mediastinal malignancy, there were 31 males and 11 females. The age at diagnosis was 8.5 (1.9, 14.9) years. Cough and wheezing (33 cases, 79%), orthopnea (19 cases, 45%) and facial edema (18 cases, 43%) occurred most commonly. T-cell lymphoblastic lymphoma (T-LBL) was the most frequent pathological diagnosis (25 cases, 60%), followed by T-cell acute lymphoblastic leukemia (T-ALL) (7 cases, 17%), anaplastic large cell lymphoma (4 cases, 10%) and diffuse large B-cell lymphoma (2 cases, 5%), peripheral T-lymphoma, Hodgkin lymphoma, Ewing's sarcoma and germ cell tumor (1 case each). Pathological diagnosis was confirmed by bone marrow aspiration or thoracentesis in 14 cases, peripheral lymph node biopsy in 6 cases, and mediastinal biopsy in 22 cases. Twenty-seven cases (64%) had local anesthesia. Respiratory complications due to mediastinal mass developed in 3 of 15 cases who received general anesthesia. Of the 42 cases, 27 cases had sustained remission, 1 case survived with second-line therapy after recurrence, and 14 cases died (2 cases died of perioperative complications and 12 cases died of recurrence or progression of primary disease). The follow-up time was 36.7 (1.2, 76.1) months for 27 cases in continuous complete remission. The 3-year overall survival (OS) and events free survival (EFS) rates of 42 children were 59% (95%CI 44%-79%) and 58% (95%CI 44%-77%) respectively. Conclusions: SVCS associated with mediastinal malignancy in children is a life-threatening tumor emergency with high mortality. The most common primary disease is T-LBL. The most common clinical symptoms and signs are cough, wheezing, orthopnea and facial edema. Clinical management should be based on the premise of stable critical condition and confirm the pathological diagnosis through minimal invasive operation.

Benchmark datasets for SARS-CoV-2 surveillance bioinformatics

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), has spread globally and is being surveilled with an international genome sequencing effort. Surveillance consists of sample acquisition, library preparation, and whole genome sequencing. This has necessitated a classification scheme detailing Variants of Concern (VOC) and Variants of Interest (VOI), and the rapid expansion of bioinformatics tools for sequence analysis. These bioinformatic tools are means for major actionable results: maintaining quality assurance and checks, defining population structure, performing genomic epidemiology, and inferring lineage to allow reliable and actionable identification and classification. Additionally, the pandemic has required public health laboratories to reach high throughput proficiency in sequencing library preparation and downstream data analysis rapidly. However, both processes can be limited by a lack of a standardized sequence dataset.

Methods

We identified six SARS-CoV-2 sequence datasets from recent publications, public databases and internal resources. In addition, we created a method to mine public databases to identify representative genomes for these datasets. Using this novel method, we identified several genomes as either VOI/VOC representatives or non-VOI/VOC representatives. To describe each dataset, we utilized a previously published datasets format, which describes accession information and whole dataset information. Additionally, a script from the same publication has been enhanced to download and verify all data from this study.

Results

The benchmark datasets focus on the two most widely used sequencing platforms: long read sequencing data from the Oxford Nanopore Technologies platform and short read sequencing data from the Illumina platform. There are six datasets: three were derived from recent publications; two were derived from data mining public databases to answer common questions not covered by published datasets; one unique dataset representing common sequence failures was obtained by rigorously scrutinizing data that did not pass quality checks. The dataset summary table, data mining script and quality control (QC) values for all sequence data are publicly available on GitHub: https://github.com/CDCgov/datasets-sars-cov-2.

Discussion

The datasets presented here were generated to help public health laboratories build sequencing and bioinformatics capacity, benchmark different workflows and pipelines, and calibrate QC thresholds to ensure sequencing quality. Together, improvements in these areas support accurate and timely outbreak investigation and surveillance, providing actionable data for pandemic management. Furthermore, these publicly available and standardized benchmark data will facilitate the development and adjudication of new pipelines.

Introduction and Establishment of SARS-CoV-2 Gamma Variant in New York City in Early 2021

BACKGROUND

Monitoring the emergence and spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants is an important public health objective. We investigated how the Gamma variant was established in New York City (NYC) in early 2021 in the presence of travel restrictions that aimed to prevent viral spread from Brazil, the country where the variant was first identified.

METHODS

We performed phylogeographic analysis on 15 967 Gamma sequences sampled between 10 March and 1 May 2021, to identify geographic sources of Gamma lineages introduced into NYC. We identified locally circulating Gamma transmission clusters and inferred the timing of their establishment in NYC.

RESULTS

We identified 16 phylogenetically distinct Gamma clusters established in NYC (cluster sizes ranged 2-108 genomes); most of them were introduced from Florida and Illinois and only 1 directly from Brazil. By the time the first Gamma case was reported by genomic surveillance in NYC on 10 March, the majority (57%) of circulating Gamma lineages had already been established in the city for at least 2 weeks.

CONCLUSIONS

Although travel from Brazil to the United States was restricted from May 2020 through the end of the study period, this restriction did not prevent Gamma from becoming established in NYC as most introductions occurred from domestic locations.

[Proximal incisal edge length and recent clinical observation of Siewert type Ⅱ advanced esophagogastric junction adenocarcinoma]

Objective: To investigate the clinical effect of the radical resection with a proximal incisal edge length of 20-25 mm and 30-35 mm in Siewert type Ⅱ advanced esophagogastric junction adenocarcinoma, to shorten the minimum safe distance of the proximal incisal edge to 20-25 mm. Methods: A retrospective cohort study method was used. The clinical data of 166 patients with Siewert type Ⅱ advanced esophagogastric junction adenocarcinoma who underwent total gastrectomy from January 2017 to August 2020 in the Department of Gastrointestinal Surgery, Heji Hospital Affiliated to Changzhi Medical College were retrospectively collected. According to the proximal incisal edge length, the patients were divided into two groups: the proximal incisal edge length of 20-25 mm group (69 cases) and 30-35 mm group (97 cases). The perioperative conditions and the 6-month follow-up after the operation were compared between the two groups. Results: There was no statistically significant difference in baseline information between the patients in the two groups (P>0.05). The operations of both groups were completed. The intraoperative operation time of the proximal incisal edge length of 20-25 mm group was shorter than that in the proximal incisal edge length of 30-35 mm group ((172±24)and(206±27)min, P<0.001). There were no significant differences in the amount of intraoperative blood loss, the treatment of the diaphragm during the operation and the positive rate of intraoperative freezing of the upper incisal edge between the patients in the two groups (all P>0.05). And there was no significant differences in the first exhaust time, gastric tube removal time, first feeding time and hospital stay after the operation of the two groups (all P>0.05). There was no significant differences in the incidence of anastomotic leakage, anastomotic stenosis, reflux esophagitis and intestinal obstruction after the operation between the patients in the two groups (all P>0.05). And there was no anastomotic leakage case among the 69 cases in the proximal incisal edge length of 20-25 mm group. Postoperative pathological treatment showed no significant differences in the vascular tumor thrombus and nerve infiltration between the two groups (both P>0.05). During the 6-month follow-up, there was no death or tumor recurrence in the two groups, and there was no significant difference in body weight loss at 6 months after the operation between the two groups (P=0.178). Conclusion: When radical resection of Siewert type Ⅱ advanced esophagogastric junction adenocarcinoma is performed, it is feasible to shorten the minimum safe distance of the proximal incisal edge to 20-25 mm under the premise of ensuring R0 resection. The operation time is shortened. Due to the shortening the incisal edge distance, the anastomotic tension is decreased, and the incidence of postoperative anastomotic leakage is also reduced.

Effect of genetic background on the evolution of Vancomycin-Intermediate Staphylococcus aureus (VISA)

Vancomycin-intermediate Staphylococcus aureus (VISA) typically arises through accumulation of chromosomal mutations that alter cell-wall thickness and global regulatory pathways. Genome-based prediction of VISA requires understanding whether strain background influences patterns of mutation that lead to resistance. We used an iterative method to experimentally evolve three important methicillin-resistant S. aureus (MRSA) strain backgrounds-(CC1, CC5 and CC8 (USA300)) to generate a library of 120 laboratory selected VISA isolates. At the endpoint, isolates had vancomycin MICs ranging from 4 to 10 μg/mL. We detected mutations in more than 150 genes, but only six genes (already known to be associated with VISA from prior studies) were mutated in all three background strains (walK, prs, rpoB, rpoC, vraS, yvqF). We found evidence of interactions between loci (e.g., vraS and yvqF mutants were significantly negatively correlated) and rpoB, rpoC, vraS and yvqF were more frequently mutated in one of the backgrounds. Increasing vancomycin resistance was correlated with lower maximal growth rates (a proxy for fitness) regardless of background. However, CC5 VISA isolates had higher MICs with fewer rounds of selection and had lower fitness costs than the CC8 VISA isolates. Using multivariable regression, we found that genes differed in their contribution to overall MIC depending on the background. Overall, these results demonstrated that VISA evolved through mutations in a similar set of loci in all backgrounds, but the effect of mutation in common genes differed with regard to fitness and contribution to resistance in different strains.

Measurement of the Cosmic Ray Helium Energy Spectrum from 70 GeV to 80 TeV with the DAMPE Space Mission

The measurement of the energy spectrum of cosmic ray helium nuclei from 70 GeV to 80 TeV using 4.5 years of data recorded by the Dark Matter Particle Explorer (DAMPE) is reported in this work. A hardening of the spectrum is observed at an energy of about 1.3 TeV, similar to previous observations. In addition, a spectral softening at about 34 TeV is revealed for the first time with large statistics and well controlled systematic uncertainties, with an overall significance of 4.3σ. The DAMPE spectral measurements of both cosmic protons and helium nuclei suggest a particle charge dependent softening energy, although with current uncertainties a dependence on the number of nucleons cannot be ruled out.

[Predictive value of platelet aggregation rate in hemodynamically significant patent ductus arteriosus in preterm infants]

Objective: To explore the predictive value of platelet aggregation rate in patent ductus arteriosus in preterm infants. Methods: This prospective nested case-control study enrolled 72 preterm infants with gestational age<32 weeks, who were admitted to Neonatal Intensive Care Unit of Xuzhou Central Hospital from August 2017 to October 2019. The echocardiography was performed on the 4^th to 5^th day after birth, and the preterm infants who met the diagnostic criteria of hemodynamically significant patent ductus arteriosus (hsPDA) were included into hsPDA group, and the control group was comprised of matched preterm infants with non-hsPDA according to the proportion of 1∶2. The basic characteristics of the preterm infants were recorded, and their complete blood counts and platelet aggregation function were examined. Clinical data were compared by student's t test and chi-square test between the two groups. The risk factors and their predictive values were analyzed by binary logistic regression analysis and receiver operating characteristic curve. Results: There were 24 preterm infants (16 boys) in the hsPDA group, and 48 (30 boys) in the control group. The incidence of neonatal respiratory distress syndrome (NRDS) grade II-IV in the hsPDA group was higher than that in the control group (67% (16/24) vs. 27% (13/48), χ²=10.422, P=0.001). The thrombocytocrit and adenosine diphosphate-induced platelet aggregation rate in the hsPDA group were lower than those in the control group (0.002 1±0.000 9 vs. 0.002 8±0.000 9, 0.21±0.10 vs. 0.32±0.07, t=-3.043 and -5.093, P=0.004 and <0.01, respectively); while the platelet volume in the hsPDA group was greater than that in the control group ((10.3±2.4) vs. (9.2±2.0) fl, t = 2.713, P = 0.033). The other platelet parameters (platelet count, platelet distribution width, and large platelet ratio) and platelet aggregation rate induced by other inducers (collagen, epinephrine and arachidonic acid) were not significantly different between the two groups (all P>0.05). The low platelet aggregation rate induced by adenosine diphosphate and low thrombocytocrit were independent risk factors for hsPDA in preterm infants (OR=4.525 and 3.994, 95%CI: 1.305-15.689 and 1.143-13.958, respectively). And the adenosine diphosphate-induced platelet aggregation rate had moderate predictive value for hsPDA in preterm infants, as the area under the receiver operating characteristic curve was 0.809, and the cutoff value was 0.245 with 0.67 sensitivity and 0.86 specificity. Conclusions: Poor platelet aggregation function and low thrombocytocrit are independent risk factors for hsPDA in preterm infants with gestational age<32 weeks. Low platelet aggregation rate induced by adenosine diphosphate has moderate predictive value for hsPDA patency.

Nosocomial infection by Klebsiella pneumoniae among neonates: a molecular epidemiological study

BACKGROUND

Nosocomial infection by Klebsiella pneumoniae (Kp) and drug resistance of Kp among neonates is a major concern. Hypervirulent K. pneumoniae (hvKp) infections are gradually increasing worldwide. Carbapenem-resistant hvKp infection has brought challenges to clinical treatment.

AIM

To evaluate the changes in drug resistance trends of Kp strains in neonatal intensive care unit (NICU) nosocomial infections, to analyse drug resistance genes and virulence genes of carbapenem-resistant K. pneumoniae (CRKP) and to identify whether these CRKP strains are hvKp.

METHODS

A total of 80 neonates with Kp nosocomial infections from 2013 to 2018 were retrospectively studied. Drug susceptibility testing was performed on 80 Kp strains, among which the 12 CRKP strains were further studied.

FINDINGS

Kp accounted for 26.9% of nosocomial infections in the NICU. CRKP strains accounted for 15.0%. Among the 80 nosocomial infection Kp strains, CRKP strains accounted for 33.3% and 53.3% in 2017 and 2018 respectively. One of the 12 CRKP strains was positive in the drawing test. The 12 CRKP strains were divided into four complete genome sequence types: cgST1 (N = 2), cgST2 (N = 1), cgST3 (N = 1), and cgST4 (N = 8). Among genes that mediated carbapenem resistance, strains of cgST4 carried NDM-5, strains of cgST2 and cgST3 carried NDM-1, and strains of cgST1 carried IMP-4. None of the 12 CRKP strains carried rmpA/rmpA2 (highly related with hvKp).

CONCLUSION

Nosocomial infections of CRKP among neonates are becoming common, but no hvKp was found among the CRKP strains in this study.

Genomic analysis of variability in Delta-toxin levels between Staphylococcus aureus strains

BACKGROUND

The delta-toxin (δ-toxin) of Staphylococcus aureus is the only hemolysin shown to cause mast cell degranulation and is linked to atopic dermatitis, a chronic inflammatory skin disease. We sought to characterize variation in δ-toxin production across S. aureus strains and identify genetic loci potentially associated with differences between strains.

METHODS

A set of 124 S. aureus strains was genome-sequenced and δ-toxin levels in stationary phase supernatants determined by high performance liquid chromatography (HPLC). SNPs and kmers were associated with differences in toxin production using four genome-wide association study (GWAS) methods. Transposon mutations in candidate genes were tested for their δ-toxin levels. We constructed XGBoost models to predict toxin production based on genetic loci discovered to be potentially associated with the phenotype.

RESULTS

The S. aureus strain set encompassed 40 sequence types (STs) in 23 clonal complexes (CCs). δ-toxin production ranged from barely detectable levels to >90,000 units, with a median of >8,000 units. CC30 had significantly lower levels of toxin production than average while CC45 and CC121 were higher. MSSA (methicillin sensitive) strains had higher δ-toxin production than MRSA (methicillin resistant) strains. Through multiple GWAS approaches, 45 genes were found to be potentially associated with toxicity. Machine learning models using loci discovered through GWAS as features were able to predict δ-toxin production (as a high/low binary phenotype) with a precision of .875 and specificity of .990 but recall of .333. We discovered that mutants in the carA gene, encoding the small chain of carbamoyl phosphate synthase, completely abolished toxin production and toxicity in Caenorhabditis elegans.

CONCLUSIONS

The amount of stationary phase production of the toxin is a strain-specific phenotype likely affected by a complex interaction of number of genes with different levels of effect. We discovered new candidate genes that potentially play a role in modulating production. We report for the first time that the product of the carA gene is necessary for δ-toxin production in USA300. This work lays a foundation for future work on understanding toxin regulation in S. aureus and prediction of phenotypes from genomic sequences.

[HIV early infant diagnosis test in HIV-exposed children in China, 2015-2017]

Objective: To understand the early infant diagnosis (EID) test rate and associated factors in HIV-exposed children in China during 2015-2017. Methods: The follow-up information cards of 12 096 HIV-exposed children for 18 months after birth during 2015-2017 were collected from the Management Information System of China's Prevention of Mother-to-Child Transmission of HIV for a retrospective analysis. The EID test characteristics of HIV exposed children and associated factors were analyzed. Results: From 2015 to 2017, the EID test rate in HIV exposed children increased from 65.6% to 83.4% in China (trend χ(2) P<0.001). The EID test rate within 8 weeks after birth increased from 61.1% to 76.8% (trend χ(2) P<0.001), but the EID positive rate decreased from 8.7% to 3.4% (trend χ(2) P<0.001). The EID positive rate in fatal HIV-exposed children was 47.7%, 36.9% and 36.3% during 2015-2017, respectively, the differences were not significant. EID test rate was associated with ethnic group, living area, survival status and the year reaching 18-month-old of the children. Conclusions: The performance of EID test has been standardized step by step in China. The positive rate of EID test decreased gradually with year. However, the EID test rates in children who were from minority ethnic groups, lived in areas with lower prevalence of HIV infection and died within 18 months after birth were relatively low.

P834Secondary prevention medications of cardiovascular diseases in China: findings from China PEACE million persons project

Background

Cardiovascular diseases (CVD) is the leading cause of death in China. Secondary prevention medications can improve the prognosis of CVD, yet little is known about the current use, variation and associated factors of these therapies in China.

Purpose

The aim of this study was to describe the current use of secondary prevention medications among patients with established CVD in the community setting in China, assess variations across population subgroups, and identify the individual characteristics associated with these therapies.

Methods

We studied 2.6 million participants aged 35–75 years from all 31 provinces in the China Patient-Centered Evaluative Assessment of Cardiac Events (PEACE) Million Persons Project, a government-funded public health program conducted from 2014 to 2018. Participants self-reported their history of ischemic heart disease (IHD) or ischemic stroke (IS) and medication use in an interview. Among participants with IHD and/or IS, we assessed the reported use of secondary prevention medications (anti-platelet drugs and statins) in the overall population and in 1,530,408 population subgroups, defined by all possible combinations of 16 factors (age, sex, urbanity, geographic region, ethnicity, occupation, annual household income, education, marital status, medical insurance, current smoker, current drinker, history of hypertension, history of diabetes, body mass index and years since diagnosis). Multivariable mixed models with a logit link function and community-specific random intercepts were fitted to assess the associations of demographic, socioeconomic and health behavior factors with the reported use of secondary prevention mediations.

Results

Among 2,613,035 screened participants, 2.9% (74,830) had history of IHD and/or IS (1.2% for IHD, 2.4% for IS). Overall, the reported use rate either anti-platelet drugs or statins was 21.9% (18.3% anti-platelet drugs, 11.0% statins, and 7.4% both). Among the 1,530,408 population subgroups, the use of secondary prevention medications varied substantially (3.4% to 52.0%). Multivariable analyses found that that younger people, women, those living in rural areas, current smokers, current drinkers, people without hypertension or diabetes, and those with established CVD for more than 2 years were less likely to take anti-platelet drugs or statins (Figure).

Forest plot of multivariable mixed model

Conclusions

The current use of secondary prevention drugs is suboptimal and varies substantially across population subgroups in China. Our study identifies target populations for interventions to improve secondary prevention of CVD.

Acknowledgement/Funding

This study was supported by the Ministry of Finance of China and National Health Commission of China

[Efficacy of magnetic levitation elastic mandibular elevator in treatment of mild or moderate obstructive sleep apnea]

Objectives: To investigate the clinical efficacy of magnetic levitation elastic mandibular elevator (MLEME) in treatment of mild obstructive sleep apnea (OSA). Methods: Twenty one patients with mild or moderate OSA confirmed by polysomnographic (PSG) examination were recruited from the First Affiliated Hospital with Nanjing Medical University between June of 2016 and June of 2017. Their PSG parameters, daytime Epworth sleepiness score (ESS) were compared before and on treatment of MLEME. In addition, any side effects and discomfort were observed during MLEME treatment. Results: Comparison of parameters during and before MLEME treatment revealed a significant decrease (all P<0.05) in apnea hypopnea index [(9.3±6.2) vs (15.6±7.8)/h], arousal index [(6.2±3.4) vs (10.3±5.4)/h], percentage of sleep time with less than 90% oxygen saturation (3.9%±2.7% vs 9.8%±3.5%), daytime ESS (6.3±2.3 vs 11.2±2.8); but a remarkable increase (all P<0.05) in mean and minimal pulse oxygen saturation (97.2%±0.9% vs 94.7%±1.1% and 87.6%±2.8% vs 81.7%±4.6% respectively). All patients could tolerate MLEME treatment well with no complain of discomfort. Following wearing of MLEME, X-ray lateral film of head and neck revealed a significantly longer distance than that before MLEME treatment from tip of uvula to posterior pharyngeal wall [(11.9±1.8) vs (9.6±1.5) mm](P<0.05). Conclusions: MLEME could significantly improve sleep respiratory parameters and daytime sleepiness of OSA without side effects. Its long-term efficacy for OSA remains to be further explored.

Measurement of the cosmic ray proton spectrum from 40 GeV to 100 TeV with the DAMPE satellite

The precise measurement of the spectrum of protons, the most abundant component of the cosmic radiation, is necessary to understand the source and acceleration of cosmic rays in the Milky Way. This work reports the measurement of the cosmic ray proton fluxes with kinetic energies from 40 GeV to 100 TeV, with 2 ¹/₂ years of data recorded by the DArk Matter Particle Explorer (DAMPE). This is the first time that an experiment directly measures the cosmic ray protons up to ~100 TeV with high statistics. The measured spectrum confirms the spectral hardening at ~300 GeV found by previous experiments and reveals a softening at ~13.6 TeV, with the spectral index changing from ~2.60 to ~2.85. Our result suggests the existence of a new spectral feature of cosmic rays at energies lower than the so-called knee and sheds new light on the origin of Galactic cosmic rays.

[International incidence trend of coal workers' pneumoconiosis and silicosis]

Pneumoconiosis is a group of occupational disease that seriously threaten the health of workers, which was regard as incurable for the irreversibility of pulmonary fibrotic lesions. It was successfully controlled in a few countries but resurgent in resent years. At the same time, the silicosis in the emerging industries has gradually appeared in many countries. In this article, the process aforementioned were described and the lessons were summarized to give some suggestions for promoting the prevention of pneumoconiosis in our country.

Clinicopathologic charcterization of sorafenib-induced endoplasmic reticulum stress in human liver cancer cells

Sorafenib (Sor) is clinical standard therapy for advanced hepatocellular carcinoma (HCC). However, detailed molecular mechanism behind Sor-exerted pharmacological effect remains unknown. In this study, sera samples, staged hepatic cancer tissues from Sor-treated patients with advanced HCC were harvested for a group of biochemical tests and immunoassays. Compared to non-treated control, blood contents of alanine transaminase (ALT), aspartate transaminase (AST), alphafetoprotein (AFP), fibroblast growth factor 21 (FGF21) were decreased in Sor-treated HCC patients, while the level of interleukin 10 (IL-10) were increased. As well, reduced triglyceride (TG), total cholesterol (T-CHOL), interferon gamma (IFN-γ), and tumor necrosis factor alpha (TNF-α) levels in sera were checked in Sor-treated HCC patients. In comparison with non-treated cancer sections, Sor-treated HCC cells showed decreased positive cells of proliferative marker for proliferating cell nuclear antigen (PCNA) and metastasized biomarker for cytokeratin 19 (CK19). In addition, elevated immunofluorescence-labeled cells of endoplasmic reticulum (ER)-stress markers of activating transcription factor 6 (ATF6), eukaryotic initiation factor 2α kinase (eIF2α), glucose-regulated protein (GRP-78), X-box binding protein 1 (XBP1) were observed in Sor-treated HCC livers. Further, validated data from Western blot assay exhibited that hepatocellular expressions of ATF6, eIF2α, GRP78, XBP1 in Sor-treated HCC liver cells were up-regulated. Briefly, our present clinicopathologic findings indicate that Sor-induced ER stress may be responsible for therapeutic mechanism against advanced HCC. In addition, induction of intracellular ER stress functions as a promising strategy for treating advanced HCC.

[Serologic surveillance indicators analysis among syphilis-infected pregnant women in East China]

Objective: To analyze serologic surveillance indicators during pregnancy among syphilis-infected women who delivered in 2013 in East China. Methods: Data were from national 'Information System of Prevention of Mother-to-child Transmission of HIV, syphilis and HBV Management' and in total 5 206 syphilis-infected pregnant women who delivered in 2013 and in East China were involved in the analysis. Information on demographic characters, laboratory tests, and treatment regimens were collected. The maternal non-treponemal testing surveillance and titer distribution were described and compare the proportions between pregnant women receiving standard testing and non-standard testing, taking baseline testing and testing before delivery or at the third trimester. Multivariate logistic regression model was analyzed using maternal titer control as dependent variable, using prior history of syphilis infection, syphilis stages, titer, gestational weeks of treatment initiation and treatment regimens as independent variables in 3 940 pregnant women with both baseline testing results and testing results before delivery or at the third trimester. Results: The ages of the 5 206 syphilis infected pregnant women were (28.1±5.8) years old. The numbers of women received penicillin treatment, other treatment regimens and no treatment were 2 967 (57.0%), 281 (5.4%), and 1 958 (37.6%), respectively. The number of women with maternal seroconversion, 4-fold or greater titer decline, or titer increase were 349 (6.7%), 251 (4.8%) and 28 (0.5%). Multivariate analysis results showed that compared with pregnant women with prior history of syphilis, the OR(95%CI) for maternal titer control was 1.49 (1.18-1.88) among those with syphilis-infection history. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks. Compared with pregnant women initiated treatment at 28 gestational weeks or before, the OR (95%CI) for maternal titer control was 4.09 (3.19-5.24) among those who initiated treatment after 28 gestational weeks or received no treatment. Compared with pregnant women received penicillin treatment, the OR (95%CI) for maternal titer control among those received non-penicillin treatment and those received no treatment were 2.35 (1.46-3.76) and 1.55 (1.13-2.12), respectively. Conclusion: In East China, the proportion of women achieved seroconversion or 4-fold or greater titer decline during pregnancy was very low. Pregnant women with no prior history of syphilis infection, early maternal initiation of treatment, and penicillin treatment were more likely to reach maternal titer control.

[Comprehensive review of factors and preventions of mother to child transmission of hepatitis B virus]

Mother-to-child transmission of hepatitis B virus (HBV) is one of major public health issues. Difference is found on effect of preventions of mother to child transmission of HBV such as Hepatitis B vaccine, Hepatitis B immunoglobulin and antiretroviral drugs. Based on the risks of hepatitis B virus on children, influencing factors and interventions of HBV mother-to-child transmission were explored to improve prevention mother-to-child transmission of hepatitis B and to search appropriate strategies reducing mother-to-child transmission of HBV.

Laboratory comparison of two Aphelinus mali clades for control of woolly apple aphid from Hebei Province, China

Aphelinus mali (Haldeman) is an effective natural enemy of woolly apple aphid (WAA), Eriosoma lanigerum (Hausmann). Previous studies have found that, with WAA from Shandong Province (Qingdao) as the host, there are significant differences in various biological characteristics between a Shandong clade and Liaoning clade of A. mali. The ability of the Shandong clade to control this aphid was significantly higher than that of the Liaoning clade in Shandong Province. In order to determine whether differences were caused by better adaptation of the Shandong parasitoid clade to the population of the host in that province or if it represents a more general fitness of this clade to control the host regardless of location, we compared the same parasitoid clades with hosts from Hebei Province. We found no significant differences in the developmental threshold temperature, effective accumulated temperature, fecundity, longevity, and oviposition period of the two clades, but the duration of host searching of the Shandong clade was significantly longer than that of the Liaoning clade. The instantaneous attack rate, the control ability (a/Th), the search parameter (Q) of the Shandong clade (0.0946, 0.543, 0.0725) of A. mali were higher than that of the Liaoning clade (0.0713, 0.382, 0.0381), and therefore, with WAA from Hebei Province as the host, the host adaptability of the Shandong clade of A. mali was not worse than that of the Liaoning clade, while the pest control ability of the Shandong clade was still greater than that of the Liaoning clade.

Biphasic hierarchical extracellular matrix scaffold for osteochondral defect regeneration

OBJECTIVE

To investigate the effect of decellularized osteochondral extracellular matrix (ECM) scaffold for osteochondral defect regeneration.

DESIGN

We compared the histological features and microstructure of degenerated cartilage to normal articular cartilage. We also generated and evaluated osteochondral ECM scaffolds through decellularization technology. Then scaffolds were implanted to osteochondral defect in rabbit model. After 12 weeks surgery, regeneration tissues were analyzed by histology, immunohistochemistry evaluation. And possible mechanisms of angiogenesis and cell migration were explored.

RESULTS

We demonstrated decreased cell numbers, formation of fibrous cartilage, lost microstructure and worse permeability in degenerated cartilage compared to normal cartilage. We also generated an osteochondral ECM scaffold with a hierarchical structure that exhibited low immunogenicity, high bioactivity, and well biocompatibility. We found that the ECM scaffold promoted tissue regeneration in osteochondral defects, which was dependent on the scaffold constituents and stratified three-dimensional microstructure as well as on its ability to inhibit angiogenesis and stimulate cell migration.

CONCLUSIONS

Our findings demonstrated that the biphasic hierarchical ECM scaffold represents a novel and effective biomaterial that can be used in the treatment of osteochondral defect.

[Clinical analysis of 19 pregnancies complicated listeriosis]

Objective: To analyze the clinical characteristics and perinatal outcomes of listeriosis during pregnancy. Methods: From July 2010 to April 2017, 70 131 women delivered in West China Second University Hospital. Nineteen cases were confirmed as listeriosis. The clinical symptoms, laboratory results, pathogens, placenta pathology and perinatal outcomes were analyzed retrospectively. Results: The median age of the 19 cases was 29.7 (19.0-42.0) years old. The median time before diagnosis was 4.8(0.5-19.0) days. The main clinical symptoms at first visits were high fever (17/19), increased white blood cells (18/19), abdominal pain (12/19). Listeria was found in samples of mother's blood (11/19), vaginal secretions (15/19), placenta (1/19), neonatal blood (4/19), neonatal phlegm (5/19) and neonatal ear secretions (1/19), respectively. Inflammation of placenta was identified in all 19 cases. Among the 19 cases, 1 was grade Ⅰ chorioamnionitis, 4 was grade Ⅱ, 5 was grade Ⅲ and 9 was grade Ⅵ. Only 4 newborn survived after therapy, and others suffered perinatal death, including 8 cases of intrauterine death, 3 cases of miscarriage and 6 cases of treatment failure. Conclusions: Listeriosis has characteristics of acute onset, quick development and high morbidity during pregnancy. The empiric use of antibiotics might not cover listeria. The understanding of listeriosis should be improved.

[Comparison of laparoscopic distal pancreatectomy and open distal pancreatectomy in pancreatic ductal adenocarcinoma]

Objective: To compare and evaluate the curative effect of laparoscopic distal pancreatectomy(LDP) and traditional open distal pancreatectomy(ODP) in pancreatic ductal adenocarcinoma. Methods: The clinical data of 15 patients treated by LDP and 87 contemporaneous cases treated by ODP from January 2010 to November 2015 was collected, and the curative effect and prognosis of these patients were retrospectively analyzed. Results: The operation time of LDP group was (286.5±48.1) min, significantly longer than that of OPD group(226.6±56.8) min (P<0.05). The operative hemorrhage, postoperative exhaust time, recovery eating time, the whole and postoperative hospitalization time of LDP group were (188.7±108.9) ml, (2.2±1.3) d, (2.9±1.1) d, (13.2±10.4) d and (9.3±8.1) d, respectively, dramatically shorter than those of ODP group (625.2±982.1) ml, (4.3±1.7) d, (5.2±1.8) d, (20.7±8.7) d and (14.9±7.8) d, respectively (all of P<0.05). There were no intraoperative blood transfusion case in LDP group, however, 13 patients in ODP group received intraoperative blood transfusion, without significant difference (P=0.207). Alternatively, 6 cases occurred pancreatic fistula in LDP group, among them, 5 cases were grade A and 1 case was grade B; In ODP group, 17 cases occurred pancreatic fistula, among them 13 cases were grade A, 1 case was grade B and 3 cases were grade C, without significant differences (P=0.130). There were 2 cases of delayed gastric empty, 1 case of pulmonary infection in LDP group. In ODP group, there were 5 cases of postoperative delayed gastric empty, 3 cases of pulmonary infection and 6 cases of intra-abdominal infection, without significant differences (P>0.05). In both LDP group and ODP group, none occurred percutaneous drainage, re-admissions, second operation or perioperative death. Conclusions: Compared to ODP, LDP is much safer and more steady in perioperative periodand operation. Patients of pancreatic ductal adenocarcinoma received LDP can acquire more benefit and recovery sooner, and LDP is a safe and effective operative method.

Chip-scale alignment of long DNA nanofibers on a patterned self-assembled monolayer

Controlled alignment of long DNA nanofibers is challenging. This communication reports a method to align human genomic DNA with nearly unlimited length using lithographically produced micro-patterns of self-assembled monolayers (SAMs) with positively charged terminal groups. The micro-patterns act as local DNA reservoirs to supply DNAs for nanofiber formation, and can also stretch and align DNA nanofibers to form an ordered array by controlling the dewetting profile. By reducing the size and inter-patch distance of a micro-patch, a nearly uniform array of long DNA nanofibers can be patterned over a large area. A controlled motion of a DNA containing droplet allows for free patterning of DNA nanofibers and production of complex structures without a transfer process. Bending of DNA nanofibers due to local distortion of the contact line bridges more adjacent micro-patches and increases the chance of producing continuous nanofibers. The interplay between surface tension and electrostatic attraction of positively charged micro-patterns allows the production of long DNA nanofibers in a simple yet powerful way.

Clinical application of a gadolinium-based capsule as an MRI contrast agent in slow transit constipation diagnostics

BACKGROUND

As a traditional method for the assessment of colon dynamics, radio-opaque markers (ROMs) are limited in clinical use because of their ionizing radiation. We compared the accuracy and applicability of gadolinium-based capsules with ROMs in the measurement of colon dynamics in healthy controls and slow transit constipation (STC) patients.

METHODS

Seven patients with STC and nine healthy controls under a normal diet orally consumed ROMs and gadolinium-based capsules simultaneously. All subjects underwent X-ray and magnetic resonance imaging (MRI). Healthy control images were acquired at 12, 24, and 48 h, and STC patient images were acquired at 24, 48, and 72 h. The scores based on the position of the labeling capsules and ROMs in the colon and the colon transit times (CTTs) in the two groups were compared.

KEY RESULTS

The CTTs obtained via the ROMs were 34.7±17.4 and 67.3±6.5 h in the healthy controls and STC patients, respectively (P<.05). The CTTs obtained via MRI were 30.9±15.9 and 74.1±7.2 h in the healthy controls and STC patients, respectively (P<.05). The CTTs of the STC patients were significantly longer than the healthy controls. The correlation (r_s ) between the scores based on the position of the labeling capsule and ROMs in the healthy group and the STC patients was .880 (P<.05) and .889 (P<.05), respectively.

CONCLUSIONS AND INFERENCES

As a MRI contrast label, gadolinium-based capsules exhibit results comparable to ROMs in colon motility measurements.