Objective: To establish a method for determining the molecular weight and molecular weight distribution of Poly(Lactide-co-Glycolide Acid) (PLGA) using Size Exclusion Chromatography-Refractive Index-Multiangle Laser Light Scattering (SEC-RI-MALLS) and Size Exclusion Chromatography-Refractive Index (SEC-RID), and to compare the results obtained from these two methods.
Methods: For SEC-RI-MALLS, tetrahydrofuran was used as the mobile phase, Shodex GPC KF-803L was employed as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, and an injection volume of 100 μL. For SEC-RID, tetrahydrofuran was also used as the mobile phase, Agilent PLgel 5 μm MIXD-D was used as the chromatographic column with a flow rate of 1 mL·min^-1, column temperature at 30 ℃, differential detector temperature at 35 ℃, and an injection volume of 20 μL. The molecular weight and molecular weight distribution were calculated using Agilent’s GPC software. The newly established methods were validated methodologically, and the molecular weight and molecular weight distribution of 13 batches of samples were determined.
Results: The precision, accuracy, stability, and repeatability tests for SEC-RI-MALLS showed RSD values of 1.35%, 1.58%, 1.53%, and 1.26%, respectively. The SEC-RID method exhibited good linearity (r=0.999 9), with RSD values for precision, accuracy, stability, and repeatability tests (n=6) of 2.05%, 1.62%, 1.30%, and 2.97%, respectively. The results obtained from SEC-RI-MALLS were lower than those from SEC-RID, and the molecular weight distribution coefficient was smaller, but the results from the paired T-test performed with the value measured by SEC-RID method and the value measured by SEC-RI-MALLS method multiplied a conversion coefficient of 1.5 showed no significant difference between the two methods.
Conclusion: Both methods are stable and reliable, and can be used for the determination of PLGA molecular weight and molecular weight distribution based on the specific situations.

BACKGROUND:Exosomes play a role in all stages of wound repair,and there is currently a large body of research on exosomes in skin wound repair,which has been shown to have great potential for clinical applications. OBJECTIVE:To summarize and discuss the main mechanisms and clinical applications of exosomes in the treatment of skin wounds,in order to promote the clinical translation of exosomes. METHODS:PubMed,clinicaltrials.gov,China National Knowledge Infrastructure,Food and Drug Administration database,and Chinese Clinical Trial Register were searched from inception to March 2023.The English search terms were"exosomes,wound healing,stem cells,chronic wound,immunoregulation,inflammation,skin,therapeutic use,isolation,characterization,infections".The Chinese search terms were"exosomes,wound healing,stem cells,immunomodulation,clinical applications".A total of 79 articles were included for the summary. RESULTS AND CONCLUSION:(1)Exosomes can improve and accelerate wound healing through inflammation regulation,immune protection,angiogenesis,cell proliferation and migration,and collagen remodeling.(2)Exosomes derived from stem cells have mature preparation techniques and related mechanism research,which is currently the mainstream research direction.Non-stem cell-derived exosomes have the advantages of convenience,economy,and easy production,and can be used as a supplement for clinical applications.(3)The clinical application of exosomes is still in its infancy,but has great potential for application.Various exosome modification techniques have laid the foundation for the future development of clinically personalized services and require further research.(4)The clinical translation of exosomes faces many challenges,such as low yield,high heterogeneity,lack of unified standards for isolation,purification,and quality control,and difficulties in storage.

Objectives:To identify the risk factors associated with delirium in intensive care unit (ICU) hospitalization of sepsis patients and construct a clinical prediction model to to provide a reference for the prevention and control of delirium in sepsis patients.Methods:Data were collected of sepsis patients admitted in the Intensive Care Unit in the Second Affiliated Hospital of Soochow University from September 2020 to August 2022.The patients were divided into delirium group and non-delirium group according to whether delirium occurred or not. Comparing of the differences in general and clinical data between the two groups, the independent risk factors for delirium were screened by backward stepwise regression method, and the delirium risk prediction model was constructed and evaluated. An independent risk factor analysis for delirium was conducted using a backward stepwise regression approach to identify significant predictors. A delirium risk prediction model was constructed based on the identified risk factors, followed by a comprehensive evaluation of the model's performance.Results:A total of 381 sepsis patients were included in the study, 114 patients (29.9%) developed delirium during the ICU hospitalization. Univariate analysis revealed statistically significant differences ( P< 0.05) between the delirium and non-delirium groups for several factors including age ≥ 65 years, blood transfusion, use of midazolam, use of adrenaline, APACHEⅡ score>15, SOFA score>4, metabolic acidosis, urea>7.1 mmol/L, coagulation disorders, lactate levels, and platelet count. Multivariate analysis identified age ≥ 65 years, use of midazolam, APACHEⅡ score>15, metabolic acidosis, urea>7.1 mmol/L, and coagulation disorders as independent risk factors for delirium in sepsis patients during ICU hospitalization.The predictive model was evaluated with an area under the ROC curve of 0.813, a non-significant Hosmer-Lemeshow goodness-of-fit test ( P=0.957>0.05), and a Brier score of 0.149 (<0.25), indicating good predictive performance and calibration. Clinical decision and impact curves demonstrated the model's favorable clinical applicability. Conclusions:The occurrence of delirium in ICU sepsis patients closely associate with six factors: age ≥ 65 years, use of midazolam, APACHEⅡ score>15, metabolic acidosis, urea>7.1 mmol/L, and coagulation disorders. This sepsis delirium prediction model has good clinical predictive ability and clinical applicability.

Objective:To explore the clinical and genetic characteristics of a fetus diagnosed with Congenital myasthenic syndrome type 16 (CMS16).Methods:A couple who had visited Tianjin Medical University General Hospital in February 2018 due to "adverse outcome of two pregnancies" was selected as the study subject. Clinical data was gathered. Peripheral blood and amniotic fluid samples were collected and subjected to whole exome sequencing (WES). Candidate variant was verified by Sanger sequencing. Low-depth whole-genome sequencing was carried out to detect copy number variation (CNV) in the fetus.Results:The couple′s first pregnancy had resulted in a miscarriage at 27 + 5 weeks, when ultrasound had revealed pleural effusion and polyhydramnios in the fetus. Their second pregnancy was terminated at 30 + 5 weeks due to fetal hand malformations, polyhydramnios and pleural fluid. Both couple had denied family history of genetic conditions. For their third pregnancy, no CNV abnormality was detected, whilst a compound heterozygous variants, including a maternally derived c. 3172C>T (p.R1058W) and paternal c. 1431delG (p.K477fs*89) in the SCN4A gene were detected. Based on the guidelines from the American College of Medical Genetics and Genomics, the c. 3172C>T (p.R1058W) was predicted as a likely pathogenic variant (PM1+ PM2_supporting+ PP3+ PP4), whilst the c. 1431delG (p.K477fs*89) was predicted as a pathogenic variant (PVS1+ PM2_supporting+ PP4). Conclusion:The c. 3172C>T (p.R1058W) and c. 1431delG (p.K477fs*89) compound heterozygous variants of the SCN4A gene probably underlay the CMS16 in the third fetus.

Objective:To established a rapid method for the determination of lactose(C12 H22 O11)content.Methods:The specific rotation([α]20D)of pure lactose was measured with lactose extract product,and the correc-tion coefficient was calculated.The measured rotatory value of the sample was multiplied by the correction coeffi-cient to obtain the mass(g)of lactose in the test product,and the lactose content was calculated.The equivalence of the newly established polarimetric method and the legal test method(HPLC-RID method)for the determination of lactose content was studied.Results:The linear relation of established method was excellent with the range of 0.05-0.20 g·mL-1(r=1.000 0)and the method also had good reproducibility(RSD=0.07％(n=6)).The lactose content of 141 batches samples measured by polarimetry was compared with the results determined by official analytical procedure,and the results showed the relative deviation between the same batches was less than 1.0％.The results of one-way ANOVA also showed that there was no significant difference between two groups(Sig.＞0.05).Conclusion:The performance of polarimetry is comparable to HPLC-RID in the Chinese Pharma-copoeia 2020 Vol Ⅳ.Meanwhile,the polarimetry can reduce the test cost,shorten the test time and meet the requirements of the quality control.

Objective:To investigate drug resistance gene in Mycoplasma pneumoniae(MP) and the distribution of 13 respiratory pathogens in bronchoalveolar lavage fluid(BALF) of children with Mycoplasma pneumoniae pneumonia(MPP).Methods:A total of 100 BALF of children with MPP in Peking University Third Hospital and Peking University First Hospital from January 2018 to January 2019 were collected.Fluorogenic quantitative PCR was used to detect nucleic acid and it′s drug resistance gene of MP and multiple PCR method was adopted to detect influenza A virus, influenza A virus-H 1N 1, influenza A virus-H 3N 2, influenza B, human parainfluenza virus, adenovirus, human bocavirus, human rhinovirus, Chlamydia pneumoniae, human metapneumovirus, MP, human coronavirus, and respi-ratory syncytial virus gene, and the results were compared by using Chi square test. Results:In 100 BALF samples, MP and drug resistance gene were detected by fluorogenic quantitative PCR.Totally, 83 cases (83.00%) were MP positive and 78 cases (93.98%) were drug resistant.All of them had the point mutations A2063G in V region of 23S rRNA domain.A total of 13 kinds of respiratory pathogens were detected by multiplex PCR method, and 89 cases (89.00%) were positive.Totally, 79 cases (79.00%) were MP positive, of which 74 cases (74.00%) detected only MP, and 5 cases (5.00%) detected MP combined with other pathogens.Other pathogens were detected in 10 cases (10.00%). The virus detection rate of 0-4 years old group was higher than that of >4-6 years old group ( P=0.042) and >6 years old group ( P=0.002), and the differences were statistically significant. Conclusions:MP can be detected in most BALF samples of MPP children, the drug resistance phenomenon is serious, and the main point mutation is A2063G.There were other respiratory pathogens and 2 or 3 pathogens were detected in a small number of BALF samples.

Objective:To investigate the risk factors affecting the prognosis of patients with extremely severe burns.Methods:Totally 46 patients with extremely severe burn in the dust explosion of aluminum powder in Kunshan, Jiangsu province on August 2, 2014 were included in this study. The patients were divided into the survival group and death group according to the prognosis of the patients. The patients' age, sex, burn degree, white blood cell, and lactic acid at admission, lactic acid at 48 h, creatinine, albumin, urine volume, blood calcium, acute physiology and chronic health score system II (APACHE II) and SOFA scores, and 90 d mortality were collected. COX regression analysis was used to analyze the possible relationship between the indicators of the two groups and the prognosis.Results:There were no significant differences in white blood cell at admission, creatinine, albumin, urine volume, SOFA score, and APACHE II score in the survival group compared with those in the death group (all P>0.05) and burn degree, the levels of lactic acid at admission, lactic acid at 48 h and blood calcium were significantly different (all P<0.05). Multivariate regression analysis showed that age, albumin and lactic acid at 48 h were independent predictors of death in patients with severe burn ( P<0.05), and these are independent outcome predictors of patients with severe burns ( P<0.05). Conclusions:Age, albumin level and lactic acid at 48 h are independent risk factors affecting the prognosis of patients with severe burns.

Objective:To observe the changes of regional saturation of cerebral oxygenation (rScO 2) and blood neuron specific enolase (NSE) in patients after cardiopulmonary resuscitation (CPR), and to explore its value in evaluating the prognosis of patients' neurological function. Methods:From January 2012 to December 2020, 97 patients with return of spontaneous circulation (ROSC) after cardiac arrest (CA) treated in the intensive care unit (ICU) of the Second Affiliated Hospital of Soochow University were selected. According to the prognosis, the patients were divided into two groups: good neurological function group [Glasgow-Pittsburgh Cerebral Performance Categories (CPC) 1-2, 20 cases] and neurological dysfunction group (CPC classification 3-5, 77 cases). The clinical data of gender, age, the number of patients with defibrillable rhythm, time of ROSC, the number of CA patients outside the hospital, acute physiology and chronic health evaluationⅡ(APACHEⅡ), Glasgow coma scale (GCS), global non-response scale (FOUR), body temperature, mean arterial pressure (MAP), blood lactic acid (Lac) and GCS at discharge, as well as the length of ICU stay, rScO 2 and blood NSE were collected. The differences of rScO 2 and NSE between the two groups were compared; and the receiver operator characteristic curve (ROC curve) was drawn to evaluate the value of rScO 2 and NSE alone or in combination in predicting the prognosis of patients with ROSC after CA. Results:The rScO 2 of good neurological function group was significantly higher than that of neurological dysfunction group at 1, 3, 6, 12, 24 and 48 hours (all P < 0.05). At 24 hours after admission, the rScO 2 on the left and right sides of good neurological function group was significantly higher than that in neurological dysfunction group [left: 0.65 (0.59, 0.76) vs. 0.55 (0.44, 0.67), right: 0.62 (0.61, 0.73) vs. 0.50 (0.30, 0.69), both P < 0.05], and NSE was significantly lower than that in the neurological dysfunction group [ng/L: 21.42 (15.38, 29.69) vs. 45.82 (24.05, 291.26), P < 0.05]. ROC curve analysis showed that both rScO 2 and NSE alone and combined detection had a certain value in predicting the prognosis of neurological function in patients with ROSC after CA, and the area under the ROC curve (AUC) detected by the combination was the largest, which was higher than the AUC predicted by rScO 2 or NSE (0.904 vs. 0.884, 0.792). When the cut-off value of combination was 0.83, the sensitivity and specificity were 75.7% and 100% respectively. Conclusion:Monitoring rScO 2 and NSE can predict the prognosis of neurological function after CPR, especially the combined evaluation of the two indexes, which can greatly improve the accuracy of diagnosis.

Objective:To evaluate the analytical sensitivity of twenty-eight respiratory pathogen nucleic acid detection kits based on different types of human adenovirus.Methods:According to the EP17-A2 document of the Clinical and Laboratory Standards Institute, probit regression analysis of 95% hit rates was performed to evaluate the limit of detection (Lod) of 28 respiratory pathogen nucleic acid detection kits. The differences between claimed Lod and measured Lod, and between different adenovirus types were compared.Results:The data showed that the claimed Lod for 50% (12/24) of the manufacturers can be accurately evaluated. There was a poor consistency in 12 kits, and the difference in 4 kits was not significant (measured Lod<5×claimed Lod), however, the difference in the other 8 kits was significant (measured Lod>5×claimed Lod, 24 000-fold increase for the most significant). The difference of measured Lod concentration between different kits was more than 10 6 orders of magnitude (the lowest and the highest were 20 copies/ml and 4.8×10 7copies/ml, respectively). An analysis of different types of adenovirus detected by the same kit revealed a wide range of measured Lod, spanning 10 4 orders of magnitude differences (the lowest and the highest were 5.0×10 3copies/ml and 4.8×10 7copies/ml, respectively). Conclusions:It is showed that there is a lack of accuracy in evaluation of the analytical sensitivity for some respiratory pathogen nucleic acid detection kits, so it is particularly necessary to use a variety of pathogen types or subtypes for performance evaluation.

Objective:To evaluate the analytical sensitivity of nine rapid influenza virus antigen diagnostic tests (RIDTs).Methods:Human seasonal influenza viruses were collected and amplified. Gene sequencing was performed and TCID 50 were tested. Evaluation of nine RIDTs for the analytical sensitivity was performed after the subsequent dilution of human seasonal influenza A H3N2, H1N1, and influenza B viruses. Results:RIDTs offers lower sensitivity than the nucleic acid amplification test. RIDTs overall had different analytical sensitivity based on the detection of the same isolate, and the difference between result was more than 10 1 TCID 50/ml. Each RIDT had variable levels of positivity with different influenza subtypes/lineages. Conclusions:The study demonstrated that the analytical sensitivity of RIDTs varies.