Objective:To investigate the dynamic trend of platelet（PLT）count and mean platelet volume（MPV）in children with severe community-acquired pneumonia（SCAP）in PICU and their correlation with prognosis.Methods:A retrospective study was conducted in 215 SCAP children who were admitted to the PICU of Beijing Children's Hospital Affiliated to Capital Medical University from January 2016 to December 2019.According to the disease outcome，the patients were divided into improvement group ( n=184) and unrecovered group ( n=31).The changes of PLT count and MPV at admission，on the 2nd，3rd，and 7th days of hospitalization and before discharge were observed，and the relationship between changes in PLT parameters and poor prognosis was analyzed. Meanwhile，the correlation between thrombocytopenia on admission and on the 7th day of hospitalization and prognosis was further explored. Results:The PLT count of improvement group at admission，on the 2nd，3rd，and 7th days of hospitalization and at discharge[(328±159, 329±137, 362±159, 439±168, 510±171)×10 9/L] were significantly higher than those of unrecovered group [(210±142, 207±152, 267±143, 260±162, 343±159)×10 9/L]（ P＜0.05）.Although the MPV of improvement group [(10.9±1.9)fL] on admission was significantly lower than that of the unrecovered group[(12.7±2.5) fL]（ P＜0.05），there was no significant difference in MPV between two groups on the 2nd，3rd，7th days of hospitalization and discharge（ P＞0.05）.In addition，compared with the admission，children in improvement group had significantly higher PLT count on the 7th day of hospitalization and before discharge（ P＜0.05），but there was no significant change in unrecovered group（ P＞0.05）.Compared with SCAP patients with thrombocytopenia at admission (PLT＜100×10 9/L)( n=22),those with thrombocytopenia on 7th day of hospitalization had a significant higher rate of non recovery( P＜0.05). Conclusion:The occurrence of thrombocytopenia on admission and after 7 days of hospitalization in children with SCAP is associated with poor prognosis.No significant increase or decrease in PLT count after 7 days of hospitalization is often indicative of poor prognosis.Dynamic monitoring of PLT parameter changes may help to better judge the prognosis of severe pneumonia.

Objective:To evaluate the relationship between the Panton-Valentine leukocidin (pvl) strain and clinical characteristics, and to describe the molecular biological characteristics of invasive Staphylococcus aureus ( S. aureus) infected clinical isolates. Methods:The isolates of S. aureus caused by invasive infection were collected in Beijing Children's Hospital Affiliated to Capital Medical University from January 2016 to December 2019, and the clinical data of the corresponding children were collected retrospectively using electronic medical records. Multilocus sequence typing, spa typing and pvl gene were analyzed using the PCR. In addition, the minimum inhibitory concentrations (MIC) of antibiotics of all isolates were detected by the micro-broth dilution method, and the isolates were divided into the pvl+ and pvl- groups according to whether or not the S. aureus isolates carried pvl. The t test and the Mann-Whitney U test were used to compare the clinical symptoms between the pvl+ and pvl- groups. Chi-square test was used to compare the drug susceptibility between the two isolates. Results:A total of 127 cases of invasive S. aureus infection were collected during the study period. The white blood cell count, neutrophil count, and C-reaction protein level in the pvl+ group were significantly higher than those in the pvl- group ( P=0.001, P=0.001, P=0.005). The rate of pvl carrier was 44.9%. Among 57 pvl+ pathogenic strains, 64.9% (37/57) were MRSA. The multidrug resistance rate of pvl- isolates was higher than that of pvl+ isolates (70% vs. 49.12%, P=0.02). Conclusions:In invasive S. aureus infection, pvl+ strain is associated with elevated inflammatory markers in children. the positive rate of pvl is higher in clinical isolates, and the multidrug resistance rate of pvl- S. aureus is higher.

Objective To investigate the health status of employees in Guangdong gas stations and analyze the factors of occupational hazards. Methods According to the records of the provincial comprehensive information system, and the division of administrative regions, a random sampling method was used to detect 22 street gas stations in the town of Xixiang, Baoan District, Shenzhen, with 335 related employees included. The hazardous factors of volatile chemical compositions were analyzed, and the results of occupational health examinations of gas station workers were evaluated. Results The occupational hazards in the volatile organic components of each oil product at 22 gas stations were analyzed, and the results showed that they all met the national standards. The occupational health status was evaluated on all employees in the gas stations in this survey. Most of them did not find any occupational hazards, but the health status of the staff in the duty room was better than that of the staff beside the tanker. Conclusion The gas station workers were at the general occupational hazard risk, but occupational protection also needs to be strengthened. Regular inspection of oil and gas recovery devices is required to improve the airtightness. Regular occupational training should be conducted to further standardize vocational operation.

Staphylococcus aureus ( S. aureus) is one of the most common human pathogens. It has been reported that Panton-Valentine Leukocidin (PVL) as a representative of virulence proteins is an important pathogenic factor for S. aureus infection. However, with the deepening of research, some researchers consider that pvl gene has little effect on the pathogenicity of S. aureus. This article aimed to review and summarize the recent studies on the features, molecular epidemiological characteristics, pathogenicity and controversy of pvl gene.

Objective This study aims to evaluate the changes of Cdk5 expression at the time of 3 hours to 10 days after moderate brain injury by blunt force impact in a rat model,and to demonstrate its forensic significance.Methods To establish a rat model of blunt focal brain contusion,and to observe the changes of Cdk5 expression in brain tissue at different timepoints after brain injury by immunohistochemistry and Western blot.Results A low expression level of Cdk5 was observed in the brain tissue of both normal and sham control groups.The expression of Cdk5 increased after 3 and 6 hours,remarkably increased at 12 hours,and reached the maximal level at 24 hours after focal brain injury.The Cdk5 level gradually decreased 3 days,5 days,7 days,and 10 days and reached the normal level 7 and 10 days after the injury,with no statistical difference (P＞0.05) compared with the normal and sham control groups.Conclusion The expression of Cdk5 increased in the peripheral area of contusion tissue after blunt brain injury in rats,showing single peak change,and dropped to normal level with the time extension.The change of Cdk5 expression may provide a new reference index for the prediction of early brain contusion.

T A R D N A-binding dom ain protein 43 (T D P-43) is a highly conserved and w idely expressed nuclear protein. N ow adays, the expression of T D P-43 can be found in m ost neurodegenerative diseases such as A lzheim er's disease, w hich m akes it becom e a neurodegenerative disease associated m arker pro-tein. From the current research status at hom eland and abroad, and around the relationship betw een the expression of T D P-43 and brain injury, this article em phatically probes into the specific expression and function of T D P-43 in acute and chronic brain injury based on the know ledge of its biological charac-teristics, w hich aim s to explore the feasibility for determ ining the cause of death and the injury and dis-ability situations by T D P-43 in forensic pathology.

ABSTRACT:Objective To investigate whether medial cerebellar nucleus may be involved in the pathogenesis of post-stroke depression (PSD)and explore the pathway that mediates this effect.Methods Healthy SD rats were randomly divided into five groups:control group,stroke group,PSD group,medial cerebellar nucleus (Med)lesion group,and superior cerebellar peduncle (xscp)lesion group.The ethological score of depression was evaluated.The neurotransmitters of Glu and GABA in the lateral hypothalamic area were detected by high performance liquid chromatography.Results Compared with those in control group,the levels of GABA and Glu expressions did not significantly differ in the lateral hypothalamic area in stroke group (P > 0.05 ).In contrast,the levels in PSD group,Med lesion group and xscp lesion group were lower than those in stroke group to different extent (P <0.01). Conclusion These results preliminarily show that medial cerebellar nucleus may participate in the pathogenesis of post-stroke depression,which may be mediated by the cerebellum-hypothalamic pathway.

Objective To study the expression of p35 and p25 in rat after focal cerebral contusion and to provide experimental data for estimating brain injury time. Methods Fifty adult male SD rats were randomly divided into 0 h, 6 h, 12 h, 24 h, 3 d, 5 d, 7 d, 10 d after focal cerebral contusion, control and sham-operated groups (5 rats each group). The focal cerebral contusion rat model was established. The expression of p35 and p25 protein of the damage peripheral zone in brain were detected by HEstain-ing, immunohistochemistry and western blotting at different injury time. Results Alarge number of p35 protein and a small amount of p25 protein were expressed in control group and sham-operated group. After focal cerebral contusion, p35 presented unimodal change with time and p25 presented bimodal changes with time. Conclusion Expression of p35 and p25 showed different regularity with good time correlation, which could help to estimate the brain injury time.

To identify the prevalence and the distribution of ticks infected with spotted fever group rickettsiae (SFGR) in Xunke Area of Heilongjiang Province ,China ,partial outer membrane protein A gene (ompA) and citrate synthase gene (gltA) specific fragments were assessed using the PCR method .The positive products were sequenced .Result showed that the pres-ence of SFGR was 14 of 60 in detection Dermacentor silvarum cases ,while the overall positive rate was 23 .33% .Its nucleotide sequence of ompA showed 99 .3% and 99 .18% similarity with nucleotide sequence of Rickettsia sp .JL-02 and Rickettsia rao-ultii respectively .And the evolutionary positions of SFGR species were similar with Rickettsiamontana and Rickettsiamassili-ae .It's concluded that the nature focus of tick-borne spotted fever did exist in the area of Xunke Area of Heilongjiang Province , China .

Brain injury is a kind of wound by violence on head, which is a mechanical distortion of skull, meninx, cerebral vascular and brain tissue due to outside force acting on head. Apolipoproteins E (ApoE ) is a major kind of apolipoprotein s, participating in the metabolismof lipid and regulating bal-ance of cholesterol. Some recent investigations showthat gene polymorphismof ApoE is associated with various kinds of diseases. Also its immunoreactivity is changed regularly with brain injury. In addition, ApoE has remarkable effect in neurological normal growth and reparative process after brain injury. This article reviews the biological characteristics and mechanismof ApoE in the repair of brain injury and application prospect in forensic medicine, which may be able to provide newideas for estimation of the brain injury time and related experimental research.