Lipopolysaccharides (LPS) are major outer membrane components of Gram-negative bacteria. Unlike most Gram-negative bacteria, Acinetobacter baumannii can still survive and acquire polymyxin resistance after complete loss of LPS. Previous studies of LPS-deficient Acinetobacter baumannii mostly focused on LPS-deficient strains induced by polymyxin, whose background was complex and unstable. To investigate LPS loss-mediated polymyxin resistant-Acinetobacter baumannii, this study constructed a stable and clear background LPS-deficient strain by knocking out lpxC gene in Acinetobacter baumannii ATCC 19606 with CIRSPR/Cas9, and then studied the phenotypic changes of the lpxC-deficient strain including morphology, growth rate, antibiotic susceptibility, virulence, membrane permeability, and membrane potential. Animal experiments were approved by the Animal Care and Welfare Committee Institute of Medicinal Biotechnology, CAMS and PUMC (approval number: IMB-20240119D₉). The results indicated that the lpxC gene of Acinetobacter baumannii ATCC 19606 was successfully knocked out. After losing the lpxC, the strain underwent the morphological change from rod-shaped to spherical. Furthermore, it leads to reduced growth rate, enhanced membrane permeability, decreased membrane potential, lower virulence, and increased antibiotic susceptibility to β-lactams, quinolones, aminoglycosides, macrolides, glycopeptides. The lpxC deletion results in significant changes in membrane homeostasis and adaptability of Acinetobacter baumannii. Understanding the phenotypic changes of colistin-resistant Acinetobacter baumannii mediated by LPS loss is useful for exploring the resistance mechanism of Acinetobacter baumannii and developing new therapeutic strategies.

The author analyzed the characteristics of phase Ⅰ clinical trials of macromolecular drugs,the characteristics of evaluation indicators of phase Ⅰ clinical trials of macromolecular drugs,such as safety evaluation,pharmacokinetic and pharmacodynamic evaluation,and efficacy evaluation.And the control points of subjects management,management of experimental macromolecule drugs,and identified and potential risk factors of macromolecule drugs in the implementation of risk management for phase Ⅰ clinical trials of macromolecule drugs were discussed in depth based on previous clinical trial research experience.Through discussion and analysis,the author suggests that each research center can formulate risk control strategies according to the actual situation,improve the efficiency of risk control,and facilitate the smooth implementation of clinical trials and improve the quality of clinical trials.

Objective:To characterize the complete genome sequence and elucidate the structural features of norovirus (NoV) isolate SD20200267.Methods:The viral nucleic acid was extracted from patient samples, followed by amplification and sequencing for genotyping based on the nucleotide sequences. The metagenomic sequencing technology was utilized for whole genome sequencing, and subsequent analysis was performed on the acquired nucleotide sequences.Results:The complete genome sequence of the SD20200267 strain, spanning a total length of 7 465 nucleotides, was successfully obtained. The SD20200267 strain belongs to the GⅡ.12 and GⅡ.P16 genotypes in the VP1 and RdRp regions, respectively. The nucleotide sequence identity of SD20200267 strain with other GⅡ.12[P16] strains ranged from 96.0% to 97.3%, exhibiting 15 amino acid variations. The strain displayed evidence of recombination, with the recombination site located in the overlapping region of ORF1 and ORF2.Conclusions:SD20200267 is classified as a GⅡ.12[P16] strain, and recombination was observed in the overlapping region of ORF1 and ORF2.

Objective:To develop a prognostic prediction model for patients with colorectal cancer based on a peripheral blood cell composite score (PBCS) system.Methods:This retrospective observational study included patients who had primary colorectal cancer without distant metastasis, who did not undergo radiotherapy or chemotherapy before surgery, who did not receive leukocyte or platelet-raising therapy within 1 month before surgery, and whose postoperative pathology confirmed colorectal adenocarcinoma with complete tumor resection. Patients with severe anemia, infection, or hematologic diseases before surgery, as well as those with severe heart, lung, or other important organ diseases or concurrent malignant tumors, were excluded. In total, 1021 patients with colorectal cancer who underwent surgical treatment in the Department of Gastrointestinal Surgery of the Fourth Hospital of Hebei Medical University from April 2018 to April 2020 were retrospectively included as the training set (766 patients) and the internal validation set (255 patients). Additionally, using the same criteria, 215 patients with colorectal cancer who underwent surgical treatment in another treatment group from March 2015 to December 2020 were selected as the external validation set. The "surv_cutpoint" function in R software was used to analyze the optimal cut-off values of neutrophils, lymphocytes, and platelets, and a PBCS system was established based on the optimal cut-off values. The scoring rules of the PBCS system were as follows: Neutrophils and platelets below the optimal cut-off value = 1 point, otherwise 0 points; Lymphocytes above the optimal cut-off value = 1 point, otherwise 0 points. The scores of the three cell types were added together to obtain the PBCS. Univariate and multivariate Cox regression analyses were performed to explore the correlation between patients' clinicopathological features and prognosis, and a nomogram was constructed based on the Cox regression analysis to predict patients' prognosis. The accuracy of the nomogram prediction model was validated using the C-index, calibration curve, and decision curve analysis.Results:The optimal cut-off values for neutrophils, lymphocytes, and platelets were 4.40×10 9/L, 1.41×10 9/L, and 355×10 9/L, respectively. The patients were divided into high and low groups according to the optimal cut-off values of these cells. Survival curve analysis showed that a high lymphocyte count (training set: P=0.042, internal validation: P=0.010, external validation: P=0.029), low neutrophil count (training set: P=0.035, internal validation: P=0.001, external validation: P=0.024), and low platelet count (training set: P=0.041, internal validation: P=0.030, external validation: P=0.024) were associated with prolonged overall survival (OS), with statistically significant differences in all cases. Survival analysis of different PBCS groups showed that patients with a high PBCS had longer OS than those with a low PBCS ( P<0.05). Univariate and multivariate Cox regression analysis results showed that aspirin use history, vascular thrombus, neural invasion, CA19-9, N stage, operation time, M stage, and PBCS were independent factors affecting OS (all P<0.05). The PBCS was also an independent factor affecting disease-specific survival ( P<0.05), but not progression-free survival ( P>0.05). The above independent risk or protective factors were included in R software to construct a nomogram for predicting OS. The C-index (0.873), calibration curve, and decision curve analysis (threshold probability: 0.0%–75.2%) all indicated that the nomogram prediction model had good predictive performance for OS. Conclusion:This study demonstrates that the PBCS constructed based on preoperative peripheral blood levels of neutrophils, lymphocytes, and platelets is an independent factor associated with the prognosis of patients with colorectal cancer. The nomogram model constructed based on this score system exhibits good predictive efficacy for the prognosis of these patients.

Objective:To develop a prognostic prediction model for patients with colorectal cancer based on a peripheral blood cell composite score (PBCS) system.Methods:This retrospective observational study included patients who had primary colorectal cancer without distant metastasis, who did not undergo radiotherapy or chemotherapy before surgery, who did not receive leukocyte or platelet-raising therapy within 1 month before surgery, and whose postoperative pathology confirmed colorectal adenocarcinoma with complete tumor resection. Patients with severe anemia, infection, or hematologic diseases before surgery, as well as those with severe heart, lung, or other important organ diseases or concurrent malignant tumors, were excluded. In total, 1021 patients with colorectal cancer who underwent surgical treatment in the Department of Gastrointestinal Surgery of the Fourth Hospital of Hebei Medical University from April 2018 to April 2020 were retrospectively included as the training set (766 patients) and the internal validation set (255 patients). Additionally, using the same criteria, 215 patients with colorectal cancer who underwent surgical treatment in another treatment group from March 2015 to December 2020 were selected as the external validation set. The "surv_cutpoint" function in R software was used to analyze the optimal cut-off values of neutrophils, lymphocytes, and platelets, and a PBCS system was established based on the optimal cut-off values. The scoring rules of the PBCS system were as follows: Neutrophils and platelets below the optimal cut-off value = 1 point, otherwise 0 points; Lymphocytes above the optimal cut-off value = 1 point, otherwise 0 points. The scores of the three cell types were added together to obtain the PBCS. Univariate and multivariate Cox regression analyses were performed to explore the correlation between patients' clinicopathological features and prognosis, and a nomogram was constructed based on the Cox regression analysis to predict patients' prognosis. The accuracy of the nomogram prediction model was validated using the C-index, calibration curve, and decision curve analysis.Results:The optimal cut-off values for neutrophils, lymphocytes, and platelets were 4.40×10 9/L, 1.41×10 9/L, and 355×10 9/L, respectively. The patients were divided into high and low groups according to the optimal cut-off values of these cells. Survival curve analysis showed that a high lymphocyte count (training set: P=0.042, internal validation: P=0.010, external validation: P=0.029), low neutrophil count (training set: P=0.035, internal validation: P=0.001, external validation: P=0.024), and low platelet count (training set: P=0.041, internal validation: P=0.030, external validation: P=0.024) were associated with prolonged overall survival (OS), with statistically significant differences in all cases. Survival analysis of different PBCS groups showed that patients with a high PBCS had longer OS than those with a low PBCS ( P<0.05). Univariate and multivariate Cox regression analysis results showed that aspirin use history, vascular thrombus, neural invasion, CA19-9, N stage, operation time, M stage, and PBCS were independent factors affecting OS (all P<0.05). The PBCS was also an independent factor affecting disease-specific survival ( P<0.05), but not progression-free survival ( P>0.05). The above independent risk or protective factors were included in R software to construct a nomogram for predicting OS. The C-index (0.873), calibration curve, and decision curve analysis (threshold probability: 0.0%–75.2%) all indicated that the nomogram prediction model had good predictive performance for OS. Conclusion:This study demonstrates that the PBCS constructed based on preoperative peripheral blood levels of neutrophils, lymphocytes, and platelets is an independent factor associated with the prognosis of patients with colorectal cancer. The nomogram model constructed based on this score system exhibits good predictive efficacy for the prognosis of these patients.

Objective To compare regional pulmonary ventilation and perfusion and ventilation/perfusion(V/Q)matching in different body positions using electrical impedance tomography(EIT).Methods Ten healthy experimental pigs were selected to collect their EIT lung ventilation and perfusion data in supine,prone,left lateral and right lateral positions.The EIT data underwent analysis and image reconstruction using MATLAB R2022b and EIDORS v3.9.The effective regions with ventilation and perfusion were determined and the V/Q matching regions were computed with the maximum pixel value 20％as the threshold.Comparisons were carried out over the V/Q matching indexes including V/Q match％,dead space％and shunt％and ventilation and perfusion distribution in regions of interest(ROIs)including ROI1,ROI2,ROI3 and ROI4 in different body positions.Results The differences in V/Q match％,dead space％and shunt％of the experimental animals in varied positions were not statistically significant(P＞0.05).The regional distribution of pulmonary ventilation and perfusion changed in different positions,and the regional distributions differed in ROIl,ROI2 and ROI3 for ventilation(P＜0.05)and in ROI1 and ROI2 for perfusion(P＜0.05).The ventilation and perfusion regions were distributed consistently with the gravity-dependent areas in supine and prone positions whereas conversely in the right and left lateral positions.Conclusion The V/Q matching indexes of one subject have high test consistency in different body positions;gravity-dependent areas varied with the changes of the body positions,which affected the distribution of pulmonary ventilation and perfusion regions;EIT can be used for measuring the changed pulmonary ventilation and perfusion due to different positions and determining the influences of position changes on pulmonary ventilation and perfusion and V/Q matching.[Chinese Medical Equipment Journal,2024,45(5):1-7]

Objective To investigate the effects of pulsed radiofrequency(PRF)with intercostal nerve block on analgesia analgesia effect,cognitive function and postoperative delirium in elderly patients undergoing thoracoscopic lung surgery.Methods Ninety elderly patients undergoing thoracoscopic lung surgery in our hospital were randomly divided into the control group(intercostal nerve block with local anesthetic drugs)and the PRF group(PRF with intercostal nerve block).The pain score,analgesic effect,cognitive function,postoperative delirium and neurological dysfunction of the two groups were compared.Results The pain scores of resting and coughing state 48 hours and 72 hours after surgery in the PRF group were significantly lower than those in the control group(P<0.05).The number of analgesic pump compression and proportion of supplemental analgesia within 72 hours after surgery and perioperative sufentanil dosage in the PRF group were significantly less than those in the control group(P<0.05).The cognitive function scores 48 hours and 72 hours after surgery in the PRF group were significantly higher than those in the control group(P<0.05).The incidence of delirium 72 hours after surgery in the PRF group was significantly lower than that in the control group(P<0.05).There was no significant difference in the incidence of intercostal nerve dysfunction 1 month,2 months and 3 months after surgery between the two groups(P>0.05).Conclusion PRF with intercostal nerve block can effectively relieve pain after elderly thoracoscopic lung surgery,reduce postoperative opioid consumption,improve postoperative cognitive function,and decrease postoperative delirium incidence without affecting the intercostal nerve function,which is safe and reliable.

Objective To investigate the effect of intravenous infusion of low-dose remifentanil on obese scarred uterine puerperae undergoing cesarean section under epidural anesthesia.Methods A total of 87 obese scarred uterine puerperae undergoing cesarean section under epidural anesthesia were selected as the study subjects,and they were randomly divided into the conventional group(n=43)and the remifentanil group(n=44).From the beginning of skin incision,puerperae of the conventional group and the remifentanil group were intravenously injected with normal saline and low-dose remifentanil respectively until the end of the operation.The vital signs,pain and comfort scores,intraoperative complications of puerperae,and status of newborns were compared between the two groups at different points during the operation.Results During fetal extraction and peritoneal exploration,the heart rate,mean arterial pressure and pain scores of puerperae in the remifentanil group were lower than those in the conventional group,and the differences were statistically significant(P<0.05);the intraoperative comfort score of puerperae in the remifentanil group was higher than that in the conventional group,and the difference was statistically significant(P<0.05).The incidence of nausea and vomiting of puerperae in the remifentanil group was lower than that in the conventional group,and the difference was statistically significant(P<0.05).There was no significant difference in the Apgar score at 1 minute and 5 minutes after delivery,requiring initial resuscitation or pH value of umbilical vein blood between newborns delivered by puerperae of the two groups(P>0.05).Conclusion Intravenous infusion of 0.05 μg·kg-1·min-1 low-dose remifentanil not only significantly reduces intraoperative pain and improves comfort of obese scarred uterine puerperae undergoing cesarean section under epidural anesthesia,but also helps to reduce the incidence of adverse reactions and ensure maternal and infant safety.

Objective:To investigate two cases of rare pathogenic genes,initiation codon mutations in HBA2 gene,combined with Southeast Asian deletion and their family members to understand the relationship of HBA2:c.2T＞C and HBA2:c.2delT mutations with clinical phenotype.Methods:The peripheral blood of family members was obtained for blood cell analysis and capillary electrophoresis hemoglobin analysis.Gap-PCR and reverse dot blotting(RDB)were used to detect common types of mutations in α-thalassaemia gene.Sanger sequencing was used to analyze HBA1 and HBA2 gene sequence.Results:Two proband genotypes were identified as--SEA/αα with HBA2:c.2T＞C and--SEA/αα with HBA2:c.2delT.HBA2:c.2T＞C/WT and HBA2:c.2delT/WT was detected in family members.They all presented with microcytic hypochromic anemia.Conclusion:When HBA2:c.2T＞C and HBA2:c.2delT are heterozygous that can lead to static α-thalassemia phenotype,and when combined with mild α-thalassemia,they can lead to the clinical manifestations of hemoglobin H disease.This study provides a basis for genetic counseling.

Objective:To characterize and analyze the genetic variation of hemagglutinin (HA) of influenza A (H1N1) pdm09 subtype virus in Shandong Province, and explore the genetic variation patterns for providing reference for influenza monitoring, epidemic prevention and control, and vaccine strain selection.Methods:HA gene sequences of the recommended strains of influenza vaccine from 2009 to 2024 and the representative strains of each branch were downloaded from the GISAID Influenza Data Platform, and were phylogenetically analyzed and characterized in terms of amino acid site variation with the HA gene sequences of 298 influenza A (H1N1) virus strains isolated from Shandong Province. A phylogenetic tree was constructed using the maximum likelihood (ML) method of the IQ-TREE online tool, and the amino acid site variants were viewed using MegAlign software. The potential glycosylation sites of the HA gene were predicted using the NetNGlyc 1.0 online software.Results:The HA gene homology of the 298 influenza A (H1N1) viruses isolated in Shandong Province ranged from 91.2% to 100.0%. The evolutionary branches were gradually distantly related over time, but the direction of evolution was roughly the same as that in other provinces. Amino acid mutations in the HA occurred every year and most were found in the antigenic determinants.Conclusions:The HA genes of influenza viruses isolated in Shandong Province from 2009 to 2024 are still in the process of continuous evolution, and continuous monitoring of the epidemiological trends and the evolutionary directions of influenza viruses is essential for early warning of influenza virus pandemics.