Clinical and microbiological characteristics of patients with biliary disease

BACKGROUND Biliary diseases are common digestive system disorders which may combine with biliary tract infection such as cholecystitis or cholangitis.Thus,rapid identification of the bacteria and their antibiotic susceptibility profiles are crucial for reducing the mortality of patients with biliary tract infection.AIM To identify bacterial species and antibiotic susceptibility for antibacterial therapy and analyze bile cultivation risk factors for increasing detection rates.METHODS This retrospective study was conducted from July 2008 to July 2017.In total,1339 bile samples which were collected during therapeutic endoscopic retrograde cholangiopan-creatography or percutaneous transhepatic cholangiodrainage or other biliary surgeries or biliary drainage were obtained to characterize pathogen spectra,antibiotic susceptibility,and clinical features.Clinical data including age,sex,comorbidities,clinical symptoms,protopathies,and history of biliary tract diseases and surgeries were collated from hospital medical records.Species identification and initial drug susceptibility were further identified by biochemical characterization using the VITEK 2 Compact test.RESULTS Positive microbiological findings were observed in 738 samples.The most frequently encountered strains were gram-negative bacteria(74.94%),including Escherichia coli(37.78%),Pseudomonas aeruginosa(8.96%),and Klebsiella pneumoniae(10.29%).Bile bacteria were largely sensitive to carbapenems,piperacillin/tazobactam,and gentamicin.Gram-negative strains had low susceptibility to ceftriaxone,quinolones and ampicillin.Almost the same microorganisms were present in patients with malignant and benign diseases.The number of samples with Klebsiella pneumoniae in the bile culture were significantly different between patients with malignant and benign diseases(55 vs 30;P=0.019).Age(P<0.001),fever(P<0.001),history of biliary tract diseases and surgeries(both P<0.001),benign disease(P=0.002),and the comorbidity chronic renal insufficiency(P=0.007)affected the positive rates of the bile samples.CONCLUSION Gram-negative bacteria were the most commonly isolated biliary bacteria.We determined the major factors associated with positive detection rates.Microbiological analysis of bile samples allowed accurate antibiotic treatments.

Over-expressed Genes Detected by Suppression Subtractive Hybridization in Carcinoma Derived From Transformed 16HBE Cells Induced by BPDE

To screen the over differentially expressed genes in carcinoma induced by BPDE-transformed 16HBE cells （16HBE-C cells）. Methods The suppression subtractive hybridization （SSH） method was performed to profile differentially expressed genes between 16HBE-C cells and 16HBE cells. The cDNA fragments of differentially expressed genes were inserted into TA cloning vector and transformed competent E. coli strain. Positive clones were randomly picked up and identified by the colony PCR method. Dot blot was used to test the same source with the tester. The differentially expressed cDNA fragments were sequenced and compared with known genes and EST database in Genbank. Results Eight known genes were over-expressed in 16HBE-C cells including eukaryotic translation elongation factor 1 alpha 1, HIF-1 responsive RTP801, ribosomal protein L10 （RPL10）, ribosomal protein S29 （RPS29）, mitochondrion related genes, and laminin receptor 1. Three differentially expressed cDNA fragments could not be matched to the known genes but to the EST database. Conclusion The SSH method can detect differentially expressed genes between 16HBE-C and 16HBE cells. BPDE-induced carcinogenesis may be related to alteration of at least eight known genes and three unknown genes. These expression data provide a clue to further cloning novel genes and studying functions in BPDE-induced carcinoma.

A novel X-ray tube spectra reconstruction method based on transmission measurements

A novel X-ray tube spectrum reconstruction method has been proposed based on transmission measurements. Aluminum bars of varying lengths attenuate the X-rays to different levels. The detectors are of lutetium yttrium oxyorthosilicate scintillator and silicon photomultiplier. With the detected X-ray intensities, the X-ray spectrum is unfolded using the least square method. The detectors, aluminum bars, and collimating apertures are integrated in a detection module made of lead. Its response to X-ray is calculated by Monte Carlo codes Geant4. Due to the high photon flux, the detectors work in current mode.The electronics system, consisting of 24-bit high-precision ADCs with 144 KSPS sampling rate and field programmable gate array, makes the data acquisition process effective and precise. Measurements on a 70-k Vp tungsten anode X-ray were taken to verify the method. The unfolded spectrum agrees well with the simulated spectrum,demonstrating that the method is reliable and practical.

Influence of Cu content on the mechanical properties and corrosion resistance of Mg-Zn-Ca bulk metallic glasses

（Mg66.aZn28.8Cas）10o-xCux （at%, x = 0, 1, 3, and 5） bulk metallic glasses （BMGs） of 2 mm in diameter were prepared by the conventional copper mold injection casting method. Besides, the influence of Cu content on the microstructure, thermal stability, mechanical properties, and corrosion behavior of Mg-Zn--Ca BMGs was investigated. It is found that the addition of Cu decreases the glass-forming ability of Mg-Zn-Ca BMGs. Crystalline phases are precipitated at a higher Cu content, larger than 3at%. The compressive fracture strength of Mg-Zn-Ca BMGs is enhanced by the addition of Cu. With the formation of in-situ composites, the compressive strength of the Mg-Zn-Ca alloy with 3at% Cu reaches 979 MPa, which is the highest strength among the Mg-Zn-Ca alloys. Furthermore, the addition of Cu also results in the increase of corrosion potential and the decrease of corrosion current density in Mg-Zn-Ca BMGs, thereby delaying their biodegradability.