Objective To investigate the mechanisms of both levofloxacin and ciprofloxacin resistance in clinical strains of Pseudomonas aeruginosa isolated from our hosptial.Methods Twenty P .aeruginosa isolates resistant to both levofloxacin and ciprofloxacin as tested by VITEK-2 Compact were collected.Agar dilution method was used to confirm their minimum inhibito-ry concentrations (MICs)of levofloxacin and ciprofloxacin.DNA gyrase (gyrA and gyrB )and topoisomerase IV (parC and parE)were analyzed by PCR amplification.The expression of efflux systems were analyzed by real-time RT-PCR.Results The MIC results were consistent between Agar dilution method and Vitek-2 Compact system.DNA gyrase (gyrA and gyrB )se-quencing analysis showed that the mutations were mainly frame-shifting mutation characteristic of base (C)insertion at position 941 in gyrA gene,deletion of base (A)at position 1588 in gyrB gene,and insertion of base (T)at position 1543 in gyrB gene.Insertion of base (C)at position 1895 in parE gene was identified in 3 strains.Overexpression of MexAB-OprM and MexCD-OprJ was detected by real-time RT-PCR.Conclusions The insertion and/or deletion of bases in DNA gyrase (gyrA and gyrB)genes and overproduction of MexAB-OprM and MexCD-OprJ efflux systems may contribute to the resistance to both ciprofloxacin and levofloxacin in clinical isolates of P .aeruginosa.

Objective To explore the MRI features of Langerhans cell histiocytosis (LCH) in central nervous system (CNS) in children. Methods Clinical and MRI data of 25 cases with LCH in CNS from three children's hospitals between January 2009 and December 2014 were retrospectively studied. All cases were confirmed by surgery or biopsy. All cases underwent non?contrast and contrast pituitary and/or cranial MRI examinations. The location, morphology, MRI signal and enhanced patterns of LCH lesions were observed and analyzed. Result A total of 17 cases had hypothalamic-pituitary LCH, with 2 of them complicated with pineal cyst, 2 complicated with brain parenchymal lesions, and one complicated with both pineal cyst and brain parenchymal lesions. MR images showed that neurohypophysis lost its original hyper?intensity on T1WI, and nodular or homogeneous thickening was seen in the pituitary stalks. Dura matter was involved in 3 cases, 2 of them had single lesion, and the other one got multiple lesions. Neoplasm in choroid plexus was seen in trigone of left lateral ventricles in one case. Three cases with pineal gland involved demonstrated cystic change. Four cases had gray matter involved, with cerebellar dentate nuclei involvement in 2 cases, and both thalamus and basal ganglia involvement in the other two cases. Three cases showed white matter involvement without obvious Virchow-Robin space enlargement and brain atrophy. Conclusions MR imaging of LCH in CNS shows certain specific characteristics. The diagnosis can be made comprehensively based on both clinic features and other imaging findings.

Objective To investigate the effect of hyperthermic intraperitoneal perfusion and cisplatinon apoptosis in human ovarian cancer cells.Methods Two human ovarian cancer cells (OVCAR-3,A2780) were divided into control group,cisplatin group,hyperthermia group and thermo-chemotherapy group;microscopy was used to observe the morphological changes of the four groups;AO/GV stain and flow cytometry(FCM) was used to analyze cell apoptosis;Apoptosis related genes caspase7,caspase8 and Bax in ovarian cancer cells were detected by fluorescence quantitative PCR.Results Inverted microscopy observeed that the ovarian cancer cells retracted and suspended partially in the cisplatin group and hyperthermia group,especially in the thermo-chemotherapy group.After AO/GV staining,the apoptotic cells were increased in the cisplatin group and hyperthermia group compared with the control group,and the thermo-chemotherapy group was more than cisplatin group and hyperthermia group.FCM results indicated that the proportion of cells apoptosis were higher in the cisplatin group and hyperthermiagroup,the thermo-chemotherapy group is the higher than the all other groups(P＜0.05).q-PCR results showed that in the thermo-treatment group the expression of pro-apoptotic genes,including caspase3,caspase6,caspase7,caspase8,caspase9,Bax,Bak and Bid,was significantly higher than other groups,apoptosis inhibitory gennes,such as Bcl-2,Bcl-xL,Mcl-1,c-FLIP,was significantly decreased than the others.Conclusions Cisplatin plus hyperthermia can promote the apoptosis in ovarian cancer cells.

BACKGROUND: Pedicle screw fixation is a common repair method for thoracolumbar fractures. Of them, pedicle screw placement into the injured vertebra is an important method. However, the long-term effects and the related biomechanical properties deserve further analysis. OBJECTIVE: To analyze the long-term effect and biomechanical characteristics of the internal fixation of thoracolumbar fractures by pedicle screw implantation. METHODS: A retrospective analysis was performed in 126 cases of thoracolumbar fractures. The patients were treated with pedicle screw implantation and the treatment was fol owed up regularly. Ten specimens of fresh calf chest and lumbar spines were obtained. Five specimens served as an experimental group to prepare models of anterior middle column fractures, and these specimens received pedicle screw fixation into the injured vertebra. The other five specimens served as the control group, and did not receive any treatment. In the two groups, along the sagittal axis, axial compression displacement, anterior flexion displacement, posterior extension displacement, torsion angle and pul -out strength were measured and recorded. RESULTS AND CONCLUSION: (1) Clinical trial results: 126 patients were fol owed up for 10-36 months. Compared with pre-treatment, compression ratio of the injured vertebra, the height of intervertebral space, vertebral slip distance, visual analogue score and Cobb angle were significantly improved at 1 month after treatment and during final fol ow-up (al P < 0.05). No significant difference in above indexed was detected between 1 month and final fol ow-up (al P > 0.05). At the end of fol ow-up, Frankel spinal cord injury grade was significantly improved (Z=-4.127, P < 0.05). After operation, three patients suffered from pulmonary infection, four patients affected urinary tract infection, and one patient experienced delayed wound healing. (2) Biomechanical results: axial compression displacement, anterior flexion displacement, posterior extension displacement, torsion angle and pul -out strength were smal er in the experimental group than in the control group (al P > 0.05). (3) Above findings showed that pedicle screw fixation into the injured vertebra for thoracolumbar fractures obtained good long-term effects, and had good biomechanical properties.

Objective To evaluate the imaging characteristics of atypical teratoid/rhab doid tumor (AT/RT) of central nervous system(CNS), and to improve the diagnostic ability of the disease. Methods The clinical and imaging findings of 9 patients were retrospectively analyzed. There were 5 male and 4 female, ages 7 months to 5 years,median age was 1.4 years. MR enhancement studies were obtained in all the cases. One case had CT enhancement examination. Results The lesions were seen in brain in 8 cases and in lumbosacral spinal cord in one case. The tumors size varied from 4.8—7.8 cm, Necrosis was seen in nine cases, cystic change in eight cases and hemorrhage in five cases. The tumors had high signal on DWI, and low signal on ADC map. Dura matter invasion(2 cases), cerebrospinal fluid spread(2 cases)and intracerebral metastasis were seen. Conclusion There are some relatively specific imaging findings of primary CNS AT/RT that could assist their diagnosis.

Objective To test the drug susceptibility of 16 Mycobactena tuberculosis isolates from patients with cutaneous tuberculosis,and to provide a basis for the treatment of this entity.Methods Sixteen strains of mycobacterium were isolated from patients with cutaneous tuberculosis.and they were consistently identified as M.tuberculosis by biochemistry and molecular biology.Absolute concentration method was used to test the susceptibility of these isolates to isoniazid.streptomycin.rifampicin and ethambutol.For two strains resistant to streptomycin,PCR and sequencing were performed to analyse the mutation of rpsL gene.Results Out ofthe 16 strains of M tuberculosis.2 were resistant to streptomycin but sensitive to isoniazid,rifampicin and ethambutol,and 14 were sensitive to isoniazid,streptomycin,rifampicin and ethambutol.Sequencing of the rpsL gene revealed a mutation of AAG to AGG at codon 43 in one streptomycinresistant strain and a substitution of CGC bv CAC at codon 54 in another resistant strain.Conclusions In past five years,the resistance ratio of M tuberculosis was low in patients with cutaneous tuberculosis,and streptomycin resistance predominated in these strains.

Objective To investigate the value of routine MRI in determining placental grading and the relationship between placental apparent diffusion coefficient(ADC)value and the gestational age(GA)in the second and third trimesters of pregnancy. Methods 52 women with singleton pregnancies were referred for MRI examination for underlying maternal or fetal lesions or malformations identified by ultrasound(US).Subjects were divided into three groups according to the GA:group Ⅰ at 18 -26 weeks(n=29);groupⅡat 27-33 weeks(n=14);group Ⅲ at 34-40 weeks(n=9).DWI protocol included 2 sets of b-values:0 s/mm2,200 s/mm2,800 s/mm2 and 50 s/mm2,200 s/mm2,800 s/mm2,and ADC values of the two groups were calculated and correlated with GA by simple linear regression.Results Half-fourier acquisition single-shot turbo spin-echo(HASTE)sequence could clearly define the 3 layers of placenta and determine the grading of placental aging.ADC values with b values of 0 s/mm2,200 s/mm2and 800 s/mm2were correlated negatively with GA (r= -0.900,P<0.001).However,ADC values with b values of 50 s/mm2,200 s/mm2and 800 s/mm2did not show any statistical correlation with GA(r= -0.037,P=0.795).Conclusion MRI can visualize the morphological changes of the placenta during the pregnancy.With a set of b-values at 0 s/mm2,200 s/mm2and 800 s/mm2,placental ADC values are found to have decreasing tendency as the pregnancies progress in the second and third trimesters.

Objective To investigate the diagnostic value of prenatal ultrasonography and magnatic resonance imaging in the fetal intracranial hemorrhage. Methods The 20 antenatal diagnosed ICH cases was collected from 31 200 prenatal diagnosis units in Guangzhou Women and Children′s Medical Center from July 2012 to June 2014. Maternal characteristics, ultrasound, and magnetic resonance imaging findings, clinical course, and postnatal outcome were reviewed. Results Twenty consecutive cases of fetal ICH were evaluated. All cases were diagnosed at mid or third trimester. Transabdominal ultrasound showed 9 cases of hyper echoic lesions in the lateral ventricle, 2 cases of hypoechonic lesions, 2 cases of irregular mixed echo in the parenchyma, 1 case of hyperechoic cerebellar hemisphere with infarction, and 1 case of abnormal choroid plexus. Seventeen cases were associated with ventriculomegaly, brain compression or brain midline displacement. MRI showed the nodular, patchy or linear low signal on T2WI and high signal on T1WI. Some cases were combined with cortex lesions or abnormal parenchyma. ICH was complicated with other structural abnormalities:1 case of cleft palate, 2 cases of spinal deformity and 3 cases of other cerebral cortical malformations. Prenatal diagnosis results were:2 cases diagnosed as positive cytomegalovirus infection and no chromosome abnormalities found in all cases. The follow up results were:1 case was lost, 16 cases were terminated after prenatal diagnosis. Among the 3 survival cases, 1 case has the neurological complication and the other two were normal till now. Conclusions Fetal intracranial hemorrhage has some image features on ultrasound and magnetic resonance. Ultrasound showed hyper echoic lesions with ventriculomegaly. MRI showed the nodular, patchy or linear low signal on T2WI and high signal on T1WI. MRI may contribute to the accuracy of diagnosis, particularly in bleeding site. The regular ultrasonic monitoring is helpful to improve the detection rate.

Objective:To investigate the serum measles antibody in children with tumor and to provide the clinical evidence for measles vaccination strategy for this special population.Methods:From January 2016 to December 2018, the blood samples of children who were diagnosed with hematological malignancy or solid tumors and received chemotherapy in the Department of Hematology or Oncology Surgery of Children′s Hospital of Fudan University were collected. Enzyme-linked immunosorbent assay was used to quantitatively detect the level of measles IgG antibody, and dynamically monitor the changes of measles antibody level during chemotherapy. Kruskal-Wallis test and chi-square test were used for statistical analysis.Results:A total of 441 children with tumors were enrolled, with the positive rate of measles antibody of 79.1%(349/441), and only 43.3%(191/441) of children had the protective level of IgG antibody. There was a statistically significant difference of the antibody protection rate in children aged0.05). The protection rate of serum measles antibody in children with hematological malignancy and solid tumor were 45.6%(78/171) and 41.9%(113/270), respectively, and there was no statistically significant ( P>0.05). There were 16.3%(16/98) of children who were observed to lose the pre-existing protective antibody during chemotherapy. There was no statistically significant difference of the protection rate of serum among children who had finished chemotherapy 0.05). Conclusions:Serum measles antibody is below the protective level in more than 50% of children with malignancy after chemotherapy. Chemotherapy can compromise the protective antibody against measles. It is recommended for this special population to re-schedule measles vaccine after individualized evaluation to acquire the immuneprotection against measles.

BACKGROUND:Some studies have shown that the hounsfield units(HU)value based on lumbar CT can be used to screen osteoporosis.At present,the number of patients with pulmonary infection has increased;the number of patients with pulmonary infection and type 2 diabetes is also increasing,which increases the utilization rate of chest CT. OBJECTIVE:To investigate the role of lumbar 1 vertebral body HU value based on chest CT in the screening of type 2 diabetes mellitus osteoporosis. METHODS:The clinical data of 244 patients with type 2 diabetes mellitus treated in the First Affiliated Hospital of Chengdu Medical College from June 2020 to June 2022 were analyzed retrospectively.The bone mineral density was obtained by dual-energy X-ray absorptiometry.According to WHO's diagnostic criteria for osteoporosis,the subjects were divided into the non-osteoporosis group(n=120)and the osteoporosis group(n=124).The general condition,T value and HU value of lumbar 1 vertebra in chest CT were compared,and the relationship between the HU value and T value of each position was analyzed and the accuracy of type 2 diabetes mellitus osteoporosis was evaluated. RESULTS AND CONCLUSION:(1)There was no significant difference in sex,age,body mass index,glycosylated hemoglobin,mean blood glucose,calcium(Ca),phosphorus(P),time of type 2 diabetes mellitus,history of hypertension and history of hyperlipidemia between the two groups(P>0.05).(2)The HU value was positively correlated with the lowest T value of the hip(r=0.619,P<0.01);the HU value was positively correlated with the hip T value(r=0.584,P<0.01),and the HU value was positively correlated with the femoral neck T value(r=0.641,P<0.01).When the HU value was 98,the prediction of type 2 diabetes mellitus osteoporosis had good accuracy,and the sensitivity was 70.8%.(3)It is concluded that the HU value of the lumbar 1 vertebra based on chest CT examination is of good value for osteoporosis screening in patients with type 2 diabetes mellitus,and may be an opportunistic and cost-free supplementary screening method for type 2 diabetes mellitus osteoporosis.