Magnetic induction method aims at the noninvasive detection of liver iron overload by measuring the hepatic magnetic susceptibility. To solve the difficulty that eddy current effects interfere with the measurement of magnetic susceptibility, we proposed an improved coil system based on the static field magnetization principle in this study. We used a direct current excitation to eliminate the eddy current effect, and a rotary receiver coil to get the induced voltage. The magnetic field for a cylindrical object due to the magnetization effect was calculated and the relative change of maximum induced voltage was derived. The correlation between magnetic susceptibility of object and maximum magnetic flux, maximum induced voltage and relative change of maximum induced voltage of the receiver coil were obtained by simulation experiments, and the results were compared with those of the theory calculation. The contrast shows that the simulation results fit the theory results well, which proves our method can eliminate the eddy current effect effectively.
Objective To investigate association between –174C/G genetic polymorphism of interleukin-6 (IL-6) and susceptibility to gastric cancer by conducting a meta-analysis. Methods Such databases as PubMed, Embase, The Cochrane Library, Web of Science, CNKI, VIP, and Wanfang Data were searched from inception to January 2017 to collect case-control studies about the correlation between the –174C/G genetic polymorphism of IL-6 and susceptibility to gastric cancer. For the population genotype distributions of both the gastric cancer group and the control group, their odds ratios (OR) and 95% confidence intervals (CI) were taken as the effect indexes were applied to conduct meta-analysis in the homozygote model (CC vs. GG), heterozygote model (GC vs. GG), dominant model (CC+CG vs. GG), recessive model (CG+GG vs. CC), and allelic genetic model (C vs. G). Two reviewers independently screened the literatures, extracted the data, and evaluated the quality of the included studies. The meta-analysis was performed using Stata 12.0 software. Results Thirteen articles were included in the final meta-analysis, covering a total of 2 062 gastric cancer cases and 3 152 controls. The results of meta-analysis showed that there was no correlation between the IL-6 –174C/G genetic polymorphism and the risk of gastric cancer〔CC vs. GG: OR=1.33, 95% CI (0.92, 1.94); GC vs. GG: OR=1.32, 95% CI (0.96, 1.82); CC+CG vs. GG: OR=1.32, 95% CI (0.97, 1.80); CG+GG vs. CC: OR=0.89, 95% CI (0.67, 1.17); C vs. G: OR=1.22, 95% CI (0.98, 1.54)〕. But the results of the subgroup analysis showed there was a significant association between the IL-6 –174 C/G genetic polymorphism and the risk of gastric cancer in Asians〔CC vs. GG: OR=1.80, 95% CI (1.29, 2.50); GC vs. GG: OR=1.51, 95% CI (1.20, 1.90); CC+CG vs. GG: OR=1.60, 95% CI (1.30, 1.96); CG+GG vs. CC: OR=0.60, 95% CI (0.44, 0.83); C vs. G: OR=1.59, 95% CI (1.24, 2.03)〕. However, no association was found in Europeans〔CC vs. GG: OR=1.11, 95% CI (0.90, 1.39); GC vs. GG: OR=1.16, 95% CI (0.98, 1.37); CC+CG vs. GG: OR=1.12, 95% CI (0.96, 1.32); CG+GG vs. CC: OR=1.07, 95% CI (0.88, 1.30); C vs. G: OR=1.04, 95% CI (0.78, 1.41)〕 . Conclusion IL-6 –174C/G genetic polymorphism is associated with susceptibility to gastric cancer in Asians, which is not associated with susceptibility to gastric cancer in Europeans.
Cryptococcosis, mainly caused by Cryptococcus neoformans/gattii species complexes, is a lethal infection in both immunosuppressive and immunocompetent populations. With the upgrade of detection methods and the increase of clinical knowledge, the incidence rate of cryptococcosis is increasing, and it has become one of the most important fungi threatening human health. In recent years, great progress has been made in this field, including the taxonomy and nomenclature of Cryptococcus spp., laboratory diagnostic methods and antifungal susceptibility tests, as well as the characteristics and treatments of cryptococcosis. This article reviews the above contents, in order to improve the clinical and laboratory understanding of the Cryptococcus spp., and realize the timely diagnosis and early treatment of cryptococcosis.
ObjectiveTo investigate the clinical settings, antibiotic susceptibilities, management and outcomes of streptococcal endophthalmitis. MethodsA retrospective observational case series study. Fifty six eyes of 56 patients diagnosed with streptococcal endophthalmitis in Eye & ENT Hospital, Fudan University from 2012 to 2022 were collected. The treatment followed the general principles of relevant guidelines, including pars plana vitrectomy (PPV), vitreous injection of antibiotics (IVI), vitreous injection of glucocorticoids and systemic application of antibiotics. The follow-up time was (11.9±17.0) months. Patients' clinical characteristics, pathogenic distribution and antibiotic susceptibilities, treatment and outcomes in their medical records were retrospectively collected and analyzed. ResultsAll 56 patients had monocular onset, including 39 (69.6%, 39/56) males and 17 (30.4%, 17/56) females, 26 (46.4%, 26/56) with left eyes involved and 30 (53.6%, 30/56) with right eyes involved. Their average age was (25.0±24.4) years. Ocular trauma was the leading cause of streptococcal endophthalmitis (73.2%, 41/56), followed by ophthalmic surgery (23.2%, 13/56) and endogenous infection (3.6%, 2/56). The streptococcal species included Streptococcus viridans (50.0%, 28/56), Streptococcus pneumoniae (18/56, 32.1%) and β-hemolytic Streptococcus (17.9%, 10/56). The susceptibility rates of Streptococcus to penicillin, cefatriaxone, vancomycin and levofloxacin were 66.0%, 57.1%, 94.1% and 92.4%, respectively. Patients received PPV+IVI and IVI as initial treatment were 49 eyes (87.5%, 49/56) and 7 eyes (12.5%, 7/56), respectively. Vitreous injection of glucocorticoids were performed in 17 eyes (30.4%, 17/56); and systemic antibiotics were applied in 52 cases (92.9%, 52/56). At the final follow-up, 47 eyes were recorded with visual acuity. Twenty (35.7%, 20/56) had best corrected visual acuity (BCVA)≥0.05 and 27 (48.2%, 27/56) had BCVA ＜0.05, of which 1 (1.8%, 1/56) had an eyeball enucleation. The etiology of endophthalmitis, streptococcal species, initial treatment with PPV, vitreous injection of glucocorticoids, and systemic antibiotics did not significantly affect patients' visual outcomes (P＞0.05). Timely visit to the hospital after the onset of symptoms (≤3 days) was significantly associated with achieving a final BCVA above 0.05 (P=0.025). ConclusionsOcular trauma was the primary cause of streptococcal endophthalmitis. Streptococcus viridans is the most common pathogenic bacterium. Streptococci had high susceptibility to vancomycin, but patients' visual outcomes were poor.
Inappropriate and irrational prescription of antimicrobial agents has led to increasing bacterial resistance, which has become a major concern around the world. Clinical microbiology service provides a basis and guarantee for the rational application of antimicrobial agents and an important technical support for antimicrobial stewardship, and plays an important role in promoting the rational use of antimicrobial agents. This paper summarizes and evaluates the specific role and technical requirements of clinical microbiology service in the diagnosis of infectious diseases, rational application of antimicrobial agents, hospital infection control and training of medical staff, so as to provide a technical guidance for clinical microbiology service in the antimicrobial stewardship.
【Abstract】ObjectiveTo investigate the expressions of hTERT mRNA and BRCA1 protein and to analyze the correlation between these two factors in breast cancer. MethodsThe expression of hTERT mRNA was examined by reverse transcription polymerase chain reaction (RT-PCR). The expression of BRCA1 protein was examined by immunohistochemistry. ResultsThe positive rates of hTERT mRNA and BRCA1 protein were 72.1%（31/43） and 34.9%（15/43） in breast cancer tissue, were 5.0%(2/40) and 77.5%(31/40) in paracancerous breast tissue respectively. Significant difference existed between breast cancer tissue and paracancerous breast tissue (P＜0.05). Significant negative correlation existed between the expression of BRCA1 protein and expression of hTERT mRNA （r=-0.995, P＜0.01）. ConclusionThe expression of hTERT mRNA is upregulated in breast cancer, and expression of BRCA1 protein is downregulated in breast cancer. BRCA1 protein expression may be associated with expression of hTERT mRNA in breast cancer, which may be involved in the carcinogenesis of breast cancer.
To assess the background field removal method usually used in quantitative susceptibility mapping (QSM), and to analyze the cause of serious artifacts generated in the truncated k-space division (TKD) method, this paper discusses a variety of background field removal methods and proposes an improved method to suppress the artifacts of susceptibility inversion. Firstly, we scanned phase images with the gradient echo sequence and then compared the quality and the speed of reconstructed images of sophisticated harmonic artifact reduction for phase data (SHARP), regularization enable of SHARP (RESHARP) and laplacian boundary value (LBV) methods. Secondly, we analyzed the reasons for reconstruction artifacts caused by the multiple truncations and discontinuity of the TKD method, and an improved TKD method was proposed by increasing threshold truncation range and improving data continuity. Finally, the result of susceptibility inversion from the improved and original TKD method was compared. The results show that the reconstruction of SHARP and RESHARP are very fast, but SHARP reconstruction artifacts are serious and the reconstruction precision is not high and implementation of RESHARP is complicated. The reconstruction speed of LBV method is slow, but the detail of the reconstructed image is prominent and the precision is high. In the QSM inversion methods, the reconstruction artifact of the original TKD method is serious, while the improved method obtains good artifact suppression image and good inversion result of artifact regions.
Quantitative susceptibility mapping (QSM) can provide tissue susceptibility information and has been adapted for clinical research and diagnosis. QSM of monkey brain in vivo at 9.4 T has not been demonstrated so far. In this study 9.4 T in vivo monkey brain QSM was performed with 200 μm isotropic high-resolution. It was found that the inherent singularity problem for QSM diverged significantly at ultra-high image resolution during regularization process and resulted in severe image artifacts. The K-space division (TKD) was applied to eliminate the artifacts, with an optimal threshold level between 0.2 and 0.3. High resolution QSM of monkey brain in vivo can thus provide a novel tool for brain research.
Magnetic susceptibility is an intrinsic physical quantity which describes the relationship between material magnetization and applied external magnetic field. Quantitative susceptibility mapping (QSM) is an MRI technology which can quantify the buck magnetic susceptibility of tissue in vivo. It is particularly effective at elucidating anatomy with paramagnetic or diamagnetic components. QSM technology is a method for solving the ill-pose problem of un-conventional de-convolution of the measured tissue magnetic field with the unit magnetic dipole field to obtain the susceptibility source map. Many multi orientation scan based QSM and clinically acceptable single orientation QSM methods have been proposed to solve this ill-posed problem. In this paper, the QSM concept is introduced and the various QSM methods are systematically categorized and discussed. The aim of this paper is to summarize the current research progress of QSM, popularize the knowledge of QSM and promote the improvements and the rational application of QSM in clinical field.
Objective To probe the distribution and drug resistance of pathogens causing surgical site infection in patients after gynecologic operation, and provide reference for prevention and treatment. Methods Seventy patients with incision infection after gynecologic operation in West China Second University Hospital of Sichuan University from January 2010 to May 2015 were selected. Species of the pathogens from the submitted specimens and the results of the drug susceptibility testing were analyzed. Results Seventy-two strains of pathogens were isolated, including 36 strains (50.0%) of Gram-negative (G–) bacteria and 36 strains (50.0%) of Gram-positive (G+) bacteria. The main G– bacteria were Escherichia coli (36.1%) and Enterobacter cloacae (5.6%); the main G+ bacteria were Staphylococcus aureus (18.1%), Staphylococcus epidermidis (12.5%), and Enterococcus faecalis (8.3%). Escherichia coli showed low sensitivities to ampicillin, ceftriaxone, and gentamicin, with resistance rates of 76.9%, 61.5%, and 61.5%, respectively. Staphylococcus aureus showed low sensitivities to penicillin G, clindamycin, and erythromycin, with resistance rates of 92.3%, 69.2%, and 61.5%, respectively. Staphylococcus epidermidis showed low sensitivities to erythromycin, penicillin G, and ciprofloxacin, with resistance rates of 88.9%, 77.8%, and 77.8%, respectively. No carbapenem-resistant G– bacteria or vancomycin-resistant G+ bacteria were detected. Conclusion Postoperative surgical site infection is the most common nosocomial infection. The main bacteria related to postoperative incision infection in the gynecology department of the hospital are Escherichia coli, Staphylococcus aureus, Staphylococcus epidermidis, and Enterococcus faecalis, which become resistant to common antibiotics currently. Therefore more attention should be paid to bacterial isolation and drug susceptibility test results for rational use of antimicrobial drugs and effectiveness of the treatment to nosocomial infection.