Antimicrobial peptides (AMPs) are small molecular peptides widely existing in the innate immunity of organisms, serving as the first line of defense. Natural AMPs possess various biological activities and are difficult to develop drug resistance. However, they are easily broken down by digestive enzymes in the body. In recent years, increasing methods have been reported to enhance the stability of AMPs, including incorporation of unnatural amino acids, chemical modifications, strategic avoidance of enzyme cleavage sites, cyclization, and nano peptide design. This review summarizes the methods for improving the stability of AMPs against protease degradation, aiming to provide references for further research in this field.
Antimicrobial Peptides/pharmacology* ; Humans ; Peptide Hydrolases/metabolism* ; Protein Stability ; Antimicrobial Cationic Peptides/chemistry* ; Anti-Infective Agents/chemistry*

【Objective】 To establish gas chromatography for the determination of tributyl phosphate(TBP) residues in human prothrombin complex and then verify it. 【Methods】 Acid modified polyethylene glycol(PEG)(20M) capillary column was used with n-hexane as solvent. The chromatographic parameters were as follows: gasification chamber temperature at 220 ℃, column temperature at 155 ℃, detector temperature at 220 ℃, column flow rate at 2.0 mL/min, carrier gas as N2, detector as FID, and collection time for 10min. The accuracy, repeatability, linearity, specificity, intermediate precision, detection limit, quantitative limit, range and durability were verified. 【Results】 The verification results showed that the method had good specificity. The linear regression correlation coefficient of standard curve was 0.999 90. The recovery rate were 98.4%, 97.5% and 95.7% when the concentration at 50%, 100%(30μg/mL) and 150%, respectively, with an average recovery of 97.2% and a relative deviation of 2.15%. When the concentration was 100%, the repeatability was 2.08%, and the relative deviation of intermediate precision was 1.63%. The detection limit was 0.255 μg/mL, and the quantitative limit was 0.511 μg/mL. After changing capillary chromatographic columns with different batch numbers but the same types and manufacturer, the applicability test of the system met the requirements, and the method had good durability. 【Conclusion】 This method can be used for the determination of TBP residues of human prothrombin complex in laboratory.

Objective To assess the association between early adiposity rebound (AR) and indices of obesity and metabolic risk in 5-year-old children. Methods Based on Ma’anshan Birth Cohort Study (MABC), single live births born in Ma'anshan of Anhui province from October 2013 to April 2015 were followed for up to 5 years consecutively. As of August 2019, 720 children with continuous measurements (≥8 times) and metabolic indicators were obtained. Physical examination and laboratory tests were used to obtain information on the birth status, length/height, weight, waist circumference, body composition and metabolic indicators of children. The 2 test, F test, t-test, non-parametric test, general linear model and logistic regression model were used for statistical analysis. Results 43.5% of the children had AR≤4 years. After controlling for gender, it was found that earlier AR was associated with overweight/obesity (OR=2.71, 95%CI: 1.81~4.05), larger waist circumference (OR=1.88, 95%CI: 1.25~2.82), and body fat percentage ≥90th percentile (OR=2.09, 95%CI: 1.26~3.48). In the earlier AR group, the insulin resistance and metabolic score were higher, but the difference was not statistically significant. At 5 years of age, the prevalence of obesity and overweight was 6.0% and 12.8%, respectively. Children with overweight/obesity, larger waist circumference, higher waist-to-weight ratio and body fat percentage ≥ 90th percentile were associated with higher insulin resistance and metabolic score, and all the differences were statistically significant (all P<0.001). Conclusion Earlier AR increased the risk of overweight/obesity, larger waist circumference, and body fat percentage ≥90th percentile at age of 5 years. Each index of the commonly used measures of childhood obesity was closely related with insulin resistance and metabolic risk factors at 5 years old.

Objective: To analyze the correlation between elective cesarean delivery and duration of breastfeeding in Ma′anshan city from 2013 to 2014. Methods: From May 2013 to September 2014, a total of 3 474 pregnant women with the first prenatal checkup were recruited from Ma′anshan maternal and child health care hospital. Finally, 3 109 pregnant women were included after exclusion of those with terminated pregnancies, adverse birth outcomes, twin or multiple pregnancies, breech traction, breech midwifery and loss of delivery information. Demographic data of pregnant women, mode of delivery and breast feeding of children were collected through questionnaires and hospital records. Logistic regression model was used to analyze the relationship between elective cesarean delivery and duration of breastfeeding in children, with the mode of delivery as independent variable and the duration of breastfeeding as dependent variable. Results: The age of 3 109 subjects was (26.6±3.6) years old, the rate of vaginal delivery was 51.1% (1 589), and the rate of elective cesarean delivery was 46.4% (1 443), among which the rate of non-indicative elective cesarean delivery was 26.4% (820), the rate of indicative elective cesarean delivery was 20.0% (623), and the rate of emergency cesarean delivery was 2.5% (77). The proportion of breastfeeding lasting until 4, 12 and 18 months was 45.0% (1 348/2 998), 23.7% (702/2 962) and 5.2% (154/2 944), respectively. After adjusting the confounding factors, compared with vaginal delivery, the OR (95%CI) values of breastfeeding for 4 months in indicative elective cesarean delivery and non-indicative elective cesarean delivery women were 0.870(0.714-1.059), 0.795(0.665-0.949), and the OR (95%CI) values of breastfeeding for 12 months were 0.772(0.611-0.975), 0.755(0.610-0.934), respectively. Conclusion Elective cesarean delivery may result in shorter duration of breastfeeding in children.

Subarachnoid hemorrhage (SAH) can be classified as traumatic SAH or spontaneous SAH based on etiology. The traumatic SAH is the common manifestation of head injury and difficult to make a diagnosis in forensic investigation. Based on practical experiences of forensic investigation and relevant references, the main points (SAH identification, examination, death mechanism) were summarized in this article. For the understanding, we try to classify the traumatic SAH into three subtypes: brain injury associated SAH, traumatic rupture of basal cerebral vessels SAH and traumatic focal SAH.
Aneurysm, Ruptured/complications* ; Cause of Death ; Craniocerebral Trauma/complications* ; Diagnosis, Differential ; Forensic Pathology ; Hematoma, Epidural, Cranial/complications* ; Humans ; Intracranial Aneurysm/complications* ; Intracranial Arteriovenous Malformations/complications* ; Rupture/complications* ; Subarachnoid Hemorrhage/pathology* ; Subarachnoid Hemorrhage, Traumatic/pathology*

Objective To study the relationship between the aged retirees' group's body mass index(BMI)distribution characteristics and relative cardiovascular diseases risk tactors.Methods One thousand three hundred and forty-three retirees in health medical examination were tested for systolic pressure, diastolic pressure,serum triglyceride,total cholesterol and fasting blood glucose.Groups with different BMI and different genders were tested for their mortality.Results The detective rates of BMI insufficiency,normal,overweight and obesity were 6.18%,51.67%,35.52%and 6.63%respectively.There was no statistic significance between different genders.The prevalence rates of hypertension,hyperlipidemia and diabetes mellitus(DM)were 46.09%,46.91%and 7.45%respectively.It showed that the prevalence rates of male hypertension and hyperlipidemia were significantly above those of the female's(P<0.05).As the BMI increased,hypertention,hyperlipidemia and DM rates increased too,and obviously increased in overweight group compared to normal BMI group(P<0.05).The detective rate of cardiovascular disease increased correspondingly with the increase of BMI.Conclusion BMI increasing is the important vascular relative risk factor for the aged retriee.