[Clinical analysis of two brothers with Imerslund-Gräsbeck syndrome]

The clinical data of two children with Imerslund-Gräsbeck syndrome (IGS) who were admitted to the First Affiliated Hospital of Zhengzhou University in August 2019 was analyzed retrospectively. The two cases were siblings, aged 8 years and 8 months and 6 years and 2 months, respectively. These two boys had megaloblastic anemia, low level of vitamin B₁₂, hyperhomocysteinemia, accompanied by proteinuria and renal tubular injury, while they showed normal folate level and renal function. Blood tandem mass spectrometry and urine organic acid analysis suggested methylmalonic acidemia (MMA). The initial diagnosis was MMA with homocysteinemia. No known pathogenic gene mutation related to MMA was found by gene sequencing. Compound heterozygous variants of amnionless (AMN) gene were detected: c.43+5G>A and c.C717G. The corrected diagnosis was IGS. Both brothers were treated with long-term intramuscular injection of vitamin B₁₂. After follow-up for one year, these two cases had no clinical symptoms, and their blood indicators remained normal, but proteinuria and renal tubular injury persisted. Blood tandem mass spectrometry and urine organic acid analysis alone may easily lead to misdiagnosis, but combined with genetic testing can improve the accuracy of diagnosis of IGS. Lifelong parenteral vitamin B₁₂ replacement therapy can effectively reverse the clinical and biochemical results, but is uncertain in alleviating albuminuria and renal tubule injury. It's necessary to monitor the renal function regularly.

Search for B^{+}→K^{+}νν[over ¯] Decays Using an Inclusive Tagging Method at Belle II

A search for the flavor-changing neutral-current decay B^{+}→K^{+}νν[over ¯] is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63  fb^{-1} collected at the ϒ(4S) resonance and a sample of 9  fb^{-1} collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B^{+}→K^{+}νν[over ¯] decay, but also the inclusive properties of the other B meson in the ϒ(4S)→BB[over ¯] event, to suppress the background from other B meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of B^{+}→K^{+}νν[over ¯] of 4.1×10^{-5} is set at the 90% confidence level.

Analytical and Clinical Performance Evaluation of ARK Fentanyl II Assay on Beckman Coulter AU System

Introduction/Objective

Drugs of abuse, specifically opioids, have been in recent years an important focus in both medicine and media due to the ‘opioid epidemic’ and large numbers of overdose deaths. Synthetic opioids such as fentanyl have contributed to this epidemic. The CDC reports that of roughly 50,000 opioid overdose deaths in 2019, nearly 73% were due to synthetic opioids. The objective of this study is to assess the analytical and clinical performance of the Fentanyl II Assay by ARK Diagnostics, Inc.

Methods/Case Report

Fentanyl was qualitatively determined by the ARK Fentanyl II Assay, a homogenous enzyme immunoassay based on competition between drug in the specimen and drug labeled with recombinant glucose-6- phosphate dehydrogenase (rG6PDH) for antibody binding sites. The presence of drug in urine increases enzyme activity, which converts nicotinamide adenine dinucleotide (NAD) to NADH in the presence of glucose-6-phosphate, resulting in an absorbance change measured by spectrophotometry. The evaluation was performed following CLSI guidelines. The analytical performance was evaluated for accuracy and precision.

Results (if a Case Study enter NA)

To evaluate the accuracy, twelve positive and eight negative specimens were tested by the ARK immunoassay performed on two Beckman Coulter instruments (AU480 and AU680) and by LC- MS/MS. The results from both instruments showed 100% agreement with the results from LC-MS/MS. On instrument AU480, the within-run CVs were 18.0% at the level of 22.510 ng/mL and 0.8% at the level of 552.628 ng/mL. The between-run CVs were 8.8% at the level of 68.928 ng/mL and 3.7% at the level of 158.947 ng/mL. On instrument AU680, the within-run CVs were 273.4% at the level of 1.052 ng/mL and 0.8% at the level of 523.788 ng/mL. The between-run CVs were 7.8% at the level of 53.779 ng/mL and 3.1% at the level of 145.263 ng/mL. In May 2021, 2,075 fentanyl assays were run at UAB. Of those, 476 returned a positive result with a positive rate of 22.9%, and 1,599 were negative with a negative rate of 77.1%. One positive result was confirmed by LC-MS/MS as negative for fentanyl but positive for norfentanyl, a metabolite of fentanyl. The clinical specificity was 99.9% and sensitivity was 100%.

Conclusion

In Conclusion, the ARK fentanyl Assay II on Beckman Coulter AU system has good accuracy, sensitivity and specificity. The precision at medium and high levels are good. However, the precision at low level needs to be improved.

Lung mesenchymal stromal cells influenced by Th2 cytokines mobilize neutrophils and facilitate metastasis by producing complement C3

Pre-metastatic niche formation is critical for the colonization of disseminated cancer cells in distant organs. Here we find that lung mesenchymal stromal cells (LMSCs) at pre-metastatic stage possess potent metastasis-promoting activity. RNA-seq reveals an upregulation of complement 3 (C3) in those LMSCs. C3 is found to promote neutrophil recruitment and the formation of neutrophil extracellular traps (NETs), which facilitate cancer cell metastasis to the lungs. C3 expression in LMSCs is induced and sustained by Th2 cytokines in a STAT6-dependent manner. LMSCs-driven lung metastasis is abolished in Th1-skewing Stat6-deficient mice. Blockade of IL-4 by antibody also attenuates LMSCs-driven cancer metastasis to the lungs. Consistently, metastasis is greatly enhanced in Th2-skewing T-bet-deficient mice or in nude mice adoptively transferred with T-bet-deficient T cells. Increased C3 levels are also detected in breast cancer patients. Our results suggest that targeting the Th2-STAT6-C3-NETs cascade may reduce breast cancer metastasis to the lungs.

The formation of the pre-metastatic niche enables the colonisation of disseminated cancer cells in distant organs. Here, the authors show that Th2 cytokines induce Complement 3 production in lung mesenchymal stromal cells, which recruits neutrophils and promotes the formation neutrophil extracellular traps, facilitating breast cancer cell metastasis to the lungs.

[Comparison of four prognostic scoring system in patients with early asymptomatic chronic lymphocytic leukemia patients]

Objective: To compare the prognostic value of four prognostic models in predicting time to first treatment (TTFT) in patients with Binet A Chinese chronic lymphocytic leukemia (CLL) . Methods: This retrospective analysis included one hundred and ten patients with Binet A CLL, initially diagnosed in the First Affiliated Hospital of Nanjing Medical University (Pukou CLL center) from June 2009 to January 2020. Risk stratification was conducted according to IPS-E, CLL-IPI, CLL1-PM, and Barcelona-Brno prognostic models. Results: Among 110 patients with Binet A CLL patients, the median age was 58 (25-84) years. The median follow-up time was 35 (4-189) months, and 57 (51.8%) patients met the indication for treatment due to symptomatic disease progression during follow-up. Log-rank analysis of nine variables was conducted involving age, Rai stage, absolute lymphocyte count (ALC) , lymph node size, lymphocyte doubling time (LDT) , β(2)-Microglobulin, IGHV status, TP53, and Del (11q) . Additionally, Rai Ⅰ-Ⅲ, ALC>15×10(9)/L, palpable lymph node size ≥1cm, β(2)-Microglobulin>3.5 mg/L, unmutated IGHV, TP53 mutation or deletion, and 11q deletion were independent risk factors of TTFT. Predictive value of each model was assessed by Harrel C-index and Akaike information criterion (AIC) with CLL1-PM (C-index=0.736, AIC=777) , followed by CLL-IPI (C-index=0.722, AIC=933) , IPS-E (C-index=0.683, AIC=1004) , and Barcelona-Brno prognostic model (C-index=0.663, AIC=986) . Conclusion: All four prognostic models effectively predicted TTFT. IPS-E might be an ideal model to guide clinical surveillance because of its easy accessibility and low expenses in routine clinical practice. Therefore, for patients receiving fluorescence in situ hybridization (FISH) and next-generation sequencing (NGS) examination at diagnosis, CLL-IPI or CLL1-PM could be applied to evaluate their prognosis more comprehensively.

Macrophage M1/M2 ratio as a predictor of pleural thickening in patients with tuberculous pleurisy

We evaluated the association between macrophage polarization and the development of pleural thickening in patients with tuberculous pleurisy. Patients with tuberculous pleurisy admitted to our hospital between October 2018 and March 2019 were prospectively recruited. Pleural fluid samples were obtained before treatment for detection of adenosine deaminase (ADA) and macrophage phenotype (M1: CD14+ CD86+; M2: CD14+ CD163+). Peripheral blood samples were subjected to interferon gamma release assay (IGRA). All subjects were administered standard anti-tuberculosis regimen (2HREZ/4HR); high-resolution CT was performed to determine pleural thickening (thickness>2mm) after completion of treatment. Pleural effusion in patients with thickened pleura had significantly more M1 but fewer M2 macrophages, and higher ADA level, as compared to those with normal pleura (P<0.05). No significant between-group difference was observed with respect to IGRA. In receiver operating characteristic (ROC) curve analysis, the optimal cut-off level of M1/M2 ratio for predicting pleural thickening was 1.149 (area under the curve: 0.842; sensitivity: 88.6%; specificity: 69.2%; positive predictive value: 86.3%; negative predictive value: 81.7%). M1/M2 ratio in the pleural fluid is a promising marker for predicting the development of pleural thickening in patients with tuberculous pleurisy. Macrophage-mediated immune response may play an important role in the pathogenesis of tuberculous pleurisy.

[Clinical characteristics of children infected with different subtypes/genotypes of human respiratory syncytial virus in Beijing from 2009 to 2017]

Objective: To explore the different clinical characteristics of children infected with different subtype/genotype of human respiratory syncytial virus (HRSV) in Beijing. Methods: Respiratory specimens for positive HRSV were randomly collected from children with acute respiratory tract infection (ARTI) in the epidemic season of HRSV from November of each year to January of the next year during 2009 and 2017. G genes of HRSV were amplified and sequenced for subtyping and genotyping by bioinformatics analysis. Clinical data were collected and analyzed. Results: Out of 590 children, 376 (63.7%) with subtype A, and 214 (36.3) with subtype B. The annual dominant subtypes of HRSV from 2009 to 2017 were B-A-A-B-AB-A-A-B-A, respectively, whilst a total of 10 genotypes were detected with 95.8% assigned to genotype ON1 and NA1 of subtype A, and genotype BA9 of subtype B. Children infected with subtype B (96 cases, 44.9%) were more likely aged 0-3 month old than those with subtype A (118 cases, 31.4%) (P=0.001), and more likely to be admitted to Intensive Care Unit(ICU) ((124 cases, 57.9%) than those with subtype A (172 cases, 45.7%)) (P=0.005). Statistical significance were shown among children infected with genotype ON1, NA1 or BA9, in the possibility of infection in children aged 0-3 month (P=0.003), proportion of admission into ICU (P=0.007), length of stay in hospital (P=0.001), and clinical outcome (P=0.001), respectively. Conclusion: Children infected with different subtype or genotype of HRSV have different clinical characteristics, which stresses the important role of the monitoring HRSV subtypes and genotypes among children.

[Da Vinci robot-assisted pylorus and vagus nerve-preserving partial gastrectomy for gastric cancer]

Objective: To investigate the safety and feasibility of Da Vinci robot-assisted pylorus and vagus nerve-preserving partial gastrectomy for gastric cancer. Methods: In this study, descriptive case series method was used to retrospectively analyze the data of 3 patients with gastric cancer who underwent Da Vinci robot-assisted pylorus and vagus nerve-preserving partial gastrectomy in the First Affiliated Hospital of Dalian Medical University from December 2020 to February 2021. The linear layout was adopted for the setting of trocar, and the co-axial direction was the line connecting the umbilicus and splenic hilum. The inferior pyloric arteries and veins need to be preserved. The center was the bifurcation of the right gastroepiploic vessel and the inferior pyloric vessel. Dissection and exposure were performed from the upper, lower, right and left sides, and ventral and dorsal sides to complete the dissection of the inferior pyloric lymph nodes. The superior border of the pancreas was treated by the right diaphragmatic crus approach, the left retroperitoneal approach and the esophageal approach to determine the distribution of the posterior vagal trunk and its branches, and to determine the anatomical relationship with the left gastric artery. The left gastric artery was cut off while the celiac branch of vagus nerve and cardia branch of left gastric artery were preserved. Lymph node dissection was performed on the lateral side of nerve fibers around the blood vessels. Result: All the 3 patients successfully completed the robotic surgery without conversion to laparoscopy or laparotomy. The operation time was (340.0±26.4) (300-390) minutes, the intraoperative blood loss was (13.3±3.3) (10-20) ml, the number of dissected lymph nodes was 26.7±3.9 (19-32), the length of pylorus canal preserved was (3.3±0.3) (3-4) cm, the distal margin was (2.3±0.3) (2-3) cm, and the proximal margin was (3.0±0.6) (2-4) cm. No postoperative complications occurred in all the 3 patients. The first flatus time was 2-3 days after operation, and the postoperative hospital stay was 6-7 days. The operation cost of the 3 patients was (40±7) (33-53) thousand yuan. Conclusion: Da Vinci robot-assisted pylorus and vagus nerve-preserving partial gastrectomy is safe and feasible.

Ginsenosides regulation of lysophosphatidylcholine profiles underlies the mechanism of Shengmai Yin in attenuating atherosclerosis

ETHNOPHARMACOLOGICAL RELEVANCE

The traditional Chinese medicine (TCM) preparation, Shengmai Yin (SMY), is widely applied in cardiovascular disease treatments. However, the pharmacological mechanism of its therapeutic effects has not been fully clarified.

AIM OF THIS STUDY

This study aimed to clearly define the efficacy and underlying mechanism of SMY and its active components in protecting against atherosclerosis.

MATERIALS AND METHODS

The pharmacological effects of SMY and its components were evaluated upon a mouse hypercholesteremia model induced by a high cholesterol diet (HCD) for 12 weeks and Apoe^-/- mice, a mouse atherosclerosis model. Pathological indicators including serum cholesterol levels, cytokines and histological changes in aortic root plaques were assessed. Untargeted metabolomic, untargeted lipidomic and targeted lipidomic changing profiles were investigated to clarify pharmacological mechanisms.

RESULTS

SMY and red ginseng crude extracts (GE) significantly decreased the serum cholesterol levels in hypercholesteremia mice and reduced the aortic root plaque areas and exerted antiatherogenic efficacy in Apoe^-/- mice. Moreover, total red ginseng saponin extracts (TGS) showed the most apparent improvement on maintaining lipid homeostasis, representing the effects of red ginseng in SMY on atherosclerosis treatment. Mechanically, TGS inhibited serum secreted phospholipase A₂ (sPLA₂) activity and lowered the serum levels of lysophosphatidylcholine (lysoPC), which is a risk factor for atherosclerosis.

CONCLUSIONS

Our findings revealed that ginsenosides from SMY exerted therapeutic effects on atherosclerosis by maintaining lipid homeostasis including cholesterol and lysoPCs.

Automatic detection of adult cardiomyocyte for high throughput measurements of calcium and contractility

Simultaneous calcium and contractility measurements on isolated adult cardiomyocytes have been the gold standard for the last decades to study cardiac (patho)physiology. However, the throughput of this system is low which limits the number of compounds that can be tested per animal. We developed instrumentation and software that can automatically find adult cardiomyocytes. Cells are detected based on the cell boundary using a Sobel-filter to find the edge information in the field of view. Separately, we detected motion by calculating the variance of intensity for each pixel in the frame through time. Additionally, it detects the best region for calcium and contractility measurements. A sensitivity of 0.66 ± 0.08 and a precision of 0.82 ± 0.03 was reached using our cell finding algorithm. The percentage of cells that were found and had good contractility measurements was 90 ± 10%. In addition, the average time between 2 cardiomyocyte calcium and contractility measurements decreased from 93.5 ± 80.2 to 15.6 ± 8.0 seconds using our software and microscope. This drastically increases throughput and provides a higher statistical reliability when performing adult cardiomyocyte functional experiments.

Biotechnological Aspects of Salt-Tolerant Xylanases: A Review

β-1,4-Xylan is the main component of hemicelluloses in land plant cell walls, whereas β-1,3-xylan is widely found in seaweed cell walls. Complete hydrolysis of xylan requires a series of synergistically acting xylanases. High-saline environments, such as saline-alkali lands and oceans, frequently occur in nature and are also involved in a broad range of various industrial processes. Thus, salt-tolerant xylanases may contribute to high-salt and marine food processing, aquatic feed production, industrial wastewater treatment, saline-alkali soil improvement, and global carbon cycle, with great commercial and environmental benefits. This review mainly introduces the definition, sources, classification, biochemical and molecular characteristics, adaptation mechanisms, and biotechnological applications of salt-tolerant xylanases. The scope of development for salt-tolerant xylanases is also discussed. It is anticipated that this review would serve as a reference for further development and utilization of salt-tolerant xylanases and other salt-tolerant enzymes.

Increased risk of diabetes in cancer survivors: a pooled analysis of 13 population-based cohort studies

BACKGROUND

Diabetes is considered as an established risk factor for cancer development. However, the link between diabetes among cancer survivors remains inconclusive. The hypothesis of this study was to assess the hazard ratio (HR) of incidence of diabetes in cancer survivors compared with the HR in the general population.

PATIENTS AND METHODS

A comprehensive literature search was performed in PubMed, Embase, and the Cochrane Library from database inception to 15 December 2020 for population-based cohort studies. Summary effect estimates were combined using random-effects models. We also performed subgroup analyses to test sources of heterogeneity and the stability of the results stratified by various study and participant characteristics.

RESULTS

Thirteen population-based cohort studies involving 1 686 595 participants were analyzed. The HR for the development of diabetes in cancer survivors was 1.39 [95% confidence interval (CI) 1.29-1.50; I2 = 82.3%; P < 0.001] compared with that in noncancer controls, among which survivors of hematological, gynecologic, breast, colorectal and urinary tract cancer (all P < 0.05) showed consistent significant results, whereas no significant increased risk was observed for other cancer types. The effects were more prominent in populations of shorter cancer survival duration (<1 year) (HR 2.09, 95% CI 1.32-3.32; P = 0.009). Moreover, cancer survivors with a longer follow-up period (>10 years) had a relatively higher risk of diabetes (HR 1.54, 95% CI 1.34-1.77) than those with a shorter follow-up period.

CONCLUSIONS

In this large pooled analysis of population-based cohorts, evidence supports the hypothesis that the risk of developing diabetes is increased in cancer survivors compared with the general population. We should interpret the results with caution for considerable interstudy heterogeneity. However, health policy makers should take this as a challenge for the early prevention and effective intervention of diabetes.

Nonsense-mediated mRNA decay efficiency influences bleeding severity in ITGA2B c.2659C > T (p.Q887X) knock-in mice

Glanzmann's thrombasthenia (GT) is a severe hemorrhagic disease. It is caused by mutations in ITGA2B or ITGB3, which are the respective genes encoding integrin αIIb and β3. Despite widespread mutational analysis, the mechanisms underlying the extensive variability in bleeding severity observed among affected individuals remains poorly understood. In order to explore the mechanisms conferring for bleeding heterogeneity, three GT patients with ITGA2B c.2671C > T (p.Q891X) who possessed different bleeding scores were studied. Analysis showed that there was significant difference in nonsense-mediated mRNA decay (NMD) efficiency among the three patients. These differences positively correlated with their bleeding score. Next, a knock-in mouse model (KI mice) with the ITGA2B c.2659C > T (p.Q887X) was generated using CRISPR/Cas9. Importantly, this mutation is homologous to ITGA2B c.2671C > T (p.Q891X) in humans. The bleeding time of KI mice was significantly in comparison to the wide-type mice. Interestingly, bleeding was stopped after treatment with caffeine, which is a known NMD inhibitor. This suggests that NMD efficiency potentially influences bleeding severity in ITGA2B c.2659C > T (p.Q887X) KI mice.

Changes in mRNA and protein levels of gonadotropin releasing hormone and receptor in ovine thymus, lymph node, spleen, and liver during early pregnancy

There exists maternal immunological modification in maternal immune organs during early pregnancy in mammals. Gonadotropin releasing hormone (GnRH) is widely distributed in vertebrate tissues, including immune organs. However, it is unclear that early pregnancy induces expression of GnRH and GnRH receptor (GnRHR) in ovine immune organs. The objective of this study was to explore the expression of GnRH and GnRHR in main immune organs (thymus, lymph node, spleen, and liver) during early pregnancy in sheep. Ovine thymus, lymph node, spleen and liver were sampled at day 16 of estrous cycle, and days 13, 16, and 25 of pregnancy. The expression of GnRH and GnRHR was detected through real-time quantitative PCR, Western blot and immunohistochemistry analysis. The results indicated that early pregnancy induced upregulation of mRNA and protein levels of GnRH and GnRHR in the maternal lymph node, spleen and liver, and mRNA and protein of GnRH in the maternal thymus, but mRNA and protein of GnRHR decreased in the maternal thymus during early pregnancy. In summary, the mRNA and protein levels of GnRH and GnRHR were changed in maternal thymus, lymph node, spleen and liver in a tissue specific manner during early pregnancy in sheep.

Efficacy and safety of glucokinase activators for type 2 diabetes mellitus therapy: a meta-analysis of double-blind randomized controlled trials

OBJECTIVE

We aimed to assess the efficacy and safety of oral glucokinase activator (GKA) in the treatment of type 2 diabetes mellitus (T2DM).

MATERIALS AND METHODS

We searched and collected randomized controlled trials (RCTs) of glucokinase activators in the treatment of T2DM from PubMed, ClinicalTrails, Cochrane Library, Web of Science, and CNKI databases. Revman5.3 software was used to do the meta-analysis, and the Cochrane tool was used to evaluate the risk of bias in the included RCTs.

RESULTS

Seven double-blind RTCs were included in the final analysis, with a total of 762 patients. For the efficacy, the meta-analysis found that GKAs lowed the levels of fasting blood glucose (FPG) (mean difference -0.71, 95% CI: -1.11 to -0.31, based on 459 patients from 5 works of literature) and glycated hemoglobin (HbA1c) (mean difference: -0.65%, 95% CI: -0.82 to -0.48, based on 570 patients from 4 works of literature). Subgroup analysis showed GKAs combined with metformin, but not used alone, reduced the levels of FPG. In terms of safety, GKAs did not affect the total rate of adverse events (AEs). GKAs did not affected the risks of diarrhea (RR 1.59, 95% CI: 0.7 to 3.65,  p =0.26), headache (RR 0.96, 95% CI: 0.41-2.21, p =0.60), and nausea (RR 2.23, 95% CI: 0.55-9.12,  p =0.24), but they increased the risk of hypoglycemia (RR 1.81, 95% CI: 1.35 to 2.42, p <0.0001, based on 570 patients from 4 literatures).

CONCLUSIONS

Oral GKAs combined with metformin has an evident hypoglycemic effect on T2DM, and they seem to be relatively good tolerant. Further clinical studies are still necessary to explore its long-term efficacy and safety.

[Analysis of the time for observation and related factors at clinics after vaccination among children's parents]

Objective: To understand the time for observation and related factors in the clinics after vaccination among children's parents. Methods: From December 2019 to January 2020, parents of children aged 0-3 years were recruited by multiple-stage sampling from 34 vaccination clinics in 12 districts and counties in 6 provinces (Shandong, Guangdong, Henan, Sichuan, Inner Mongolia, and Liaoning). A questionnaire survey on the time of observation after vaccination was conducted. A multivariate logistic regression model was used to analyze the related factors of parental observation time after vaccination. Results: A total of 3 292 parents of 0-3 year's old children were selected, and 3 178 parents were finally included in the analysis. 87.85%(2 792/3 178) of the parents reported that the observation time after vaccination at clinics was ≥30 minutes. Multivariate logistic regression analysis showed that, after adjusting for the regions, the main factors affecting the observation time at clinics after vaccination among parents appeared as observation time informed by physicians at the clinic appeared ≥30 minutes (OR=31.622, 95%CI: 19.847-50.384), parents were medical personnel (OR=2.779, 95%CI: 1.505-5.133), parents being volunteers working on vaccination-related publicity and education activities (OR=1.986, 95%CI: 1.438-2.743), parents aged 35 years old or above (OR=1.900, 95%CI: 1.215-2.971), being parents of the first child (OR=1.663, 95%CI: 1.282-2.156), per capita annual income of the family as 8 000- Yuan (OR=1.646, 95%CI: 1.168-2.319), children aged 0-12 months old (OR=1.646, 95%CI: 1.203-2.252) or 13-24 months old (OR=1.506, 95%CI: 1.064-2.133), obedient to physicians' advice at the clinic (OR=1.481, 95%CI: 1.067-2.055). Conclusions: The proportions of parents observed for ≥30 minutes at the clinics of vaccination were high. When the information was from the physicians at the vaccination clinic, the observation time was the most critical factor for parents to observe at clinics as required.

[Analysis of pathogen distribution and drug resistance of acute,delayed and chronic periprosthetic joint infection]

Objective: To analyze the pathogen distribution and drug resistance in acute,delayed and chronic periprosthetic joint infection (PJI). Methods: The clinical data of 316 patients with periprosthetic infection after primary hip and knee arthroplasty admitted to the Department of Arthroplasty,the First Affiliated Hospital,Xinjiang Medical University from August 2010 to August 2020 were retrospectively analyzed.There were 146 males and 170 females,aged (62.3±14.2) years (range:22 to 89 years).One hundred and sixty one patients underwent total hip arthroplasty and 155 patients underwent total knee arthroplasty.According to the time of postoperative infection,the patients were divided into acute PJI group (65 cases),delayed PJI group (83 cases) and chronic PJI group (168 cases).The results of pathogen species,composition ratio and drug susceptibility tests were collected,and the independent sample t test,Chi-square test or Fisher's exact probability test were used for comparison. Results: Gram-positive bacteria were the main pathogens of PJI (49.7%,157/316),and the positive rates of culture in patients with acute PJI,delayed PJI and chronic PJI were 33.8% (22/65),55.4% (46/83) and 53.0% (89/168),and the difference was statistically significant(χ²=8.343,P=0.015).The common bacteria were coagulase-negative Staphylococcus (54.8%,86/157) and Staphylococcus aureus (30.6%,48/157),The drug-sensitivity to linezolid,vancomycin and tigacycline was 100%.The gram-negative bacteria were mainly Escherichia coli and Enterobacter cloacae,and the drug resistance rate to carbapenems was low,ranging from 0 to 9.09%.The drug resistance rates of acute PJI patients to rifampicin,ciprofloxacin and erythromycin were significantly higher than those of late onset and chronic PJI patients,the difference was statistically significant(rifampicin:χ²=14.332,P=0.001;ciprofloxacin:χ²=12.086,P=0.002;erythromycin:χ²=9.096,P=0.010);The drug resistance rate of acute PJI patients to levofloxacin,clindamycin and tetracycline was higher than that of chronic PJI patients,and the difference was statistically significant(levofloxacin:χ²=10.500,P=0.002; clindamycin: χ²=7.103,P=0.007; tetracycline: χ²=6.909,P =0.012).The resistance rate of ampicillin/sulbactam in acute PJI (60.0%) was significantly higher than that in chronic PJI (16.7%),and the difference was statistically significant(χ²= 5.853,P=0.040). Conclusion: Gram-positive bacteria are the main pathogens of PJI,and the resistance rate of pathogens of acute PJI is higher than that of late onset and chronic PJI.

Multi-Layer Counter-Pressure Injection Molding for Thick-Walled Optical Lens

In precision optical applications, plastics thick-walled optical lenses are increasing. Dimensional stability and optical performance are the critical issues that should be addressed for plastic thick-walled lenses. A novel multi-layer counter-pressure injection molding process is proposed in this study. The experimental prism mold with moveable pistons was developed to investigate the effects of layering methods, counter-pressure and their combination on thick-walled optical lenses. The experimental results reveal that counter-pressure injection molding is effective in improving shrinkage, transmittance and refractive index of the thick-walled optical prism. Counter-pressure of the piston provided lower melt velocity and shorter flow path of melt to improve polymer molecules orientation, and also offered continuous holding pressure during the filling stage to eliminate defects such as shrinkage or short shots. The combination of counter-pressure and multi-layer injection molding technology further improved the dimension stability and optical performance of the thick-walled optical lens. Much thinner layers than the final wall thickness of prism ensures shrinkage reduction during the cooling stages. A thick-walled optical prism was fabricated successfully upon applying a multi-layer counter-pressure injection molding process.