Genetic basis of chromosomally-encoded mcr-1 gene

Compared with plasmid-borne mcr-1, the occurrence of chromosomally-encoded mcr-1 is rare although it has been reported in several cases. This study aimed to investigate the genetic features of chromosomally-encoded mcr-1 among Escherichia coli strains as well as the potential genetic basis governing mobilisation of mcr-1 in bacterial chromosomes. The genome sequences of 16 E. coli strains containing a chromosomal mcr-1 gene were obtained and analysed. Phylogenetic and whole-genome sequencing (WGS) analysis demonstrated that mcr-1 was associated with four major types of genetic arrangements, namely ISApl1–mcr1–orf, Tn6330, complex Tn6330 and ΔTn6330 in chromosomes of genetically unrelated E. coli strains. The mcr-1-carrying mobile elements were shown to insert into the AT-rich region, which was also the case for ISApl1. Analysis of complete E. coli genome sequences showed that there were multiple copies of ISApl1 present in E. coli chromosomes that also carried mcr-1, whilst all mcr-1-negative chromosomes were absent of any copy of ISApl1, suggesting the strong association of ISApl1 and mcr-1. Insertion of ISApl1 into E. coli chromosomes may be a prerequisite for the insertion of mcr-1-carrying mobile elements. Insertion of mcr-1 into E. coli chromosomes would enable it to become intrinsically resistant, which is expected to become more prevalent. Policy on the prudent use of colistin both in veterinary and clinical settings should be imposed globally to further prevent dissemination of mcr-1 in E. coli and other bacterial pathogens.     

腹腔镜联合药物治疗卵巢子宫内膜异位囊肿合并不孕的疗效分析

目的探讨腹腔镜联合药物治疗中重度卵巢子宫内膜异位囊肿(OEM)合并不孕的临床疗效。方法选取我院在2011年1月至2014年1月收治的中重度OEM合并不孕患者120例,随机分为A组、B组和对照组各40例,三组患者均行腹腔镜保守性手术治疗,对照组术后不联合药物治疗,A、B两组术后联合药物治疗,其中A组给予诺雷德肌肉注射,B组给予孕三烯酮胶囊口服治疗,并比较三组术后性激素水平、妊娠率、复发率和安全性。结果性激素水平的比较,A组、B组术后6个月FSH、LH、E2、CA125等指标均明显优于对照组(p<0.05);妊娠率和复发率比较,A组、B组两组妊娠率明显大于对照组(p<0.05),复发率明显小于对照组(p<0.05),且A组复发率明显小于B组(p<0.05);A组4例(10%)患者出现谷丙转氨酶(ALT)、谷草转氨酶(AST)转高,其它两组无不良事件发生。结论腹腔镜联合药物治疗中重度OEM合并不孕效果显著,可明显降低复发率提高妊娠率,且给予诺雷德治疗可更好的降低复发率,且安全性高。     

Cloning and characterization of voltage‐gated calcium channel alpha1 subunits in Xenopus laevis during development

Voltage‐gated calcium channels play a critical role in regulating the Ca²⁺ activity that mediates many aspects of neural development, including neural induction, neurotransmitter phenotype specification, and neurite outgrowth. Using Xenopus laevis embryos, we describe the spatial and temporal expression patterns during development of the 10 pore‐forming alpha1 subunits that define the channels' kinetic properties. In situ hybridization indicates that Ca_V1.2, Ca_V2.1, Ca_V2.2, and Ca_V3.2 are expressed during neurula stages throughout the neural tube. These, along with Ca_V1.3 and Ca_V2.3, beginning at early tail bud stages, and Ca_V3.1 at late tail bud stages, are detected in complex patterns within the brain and spinal cord through swimming tadpole stages. Additional expression of various alpha1 subunits was observed in the cranial ganglia, retina, olfactory epithelium, pineal gland, and heart. The unique expression patterns for the different alpha1 subunits suggests they are under precise spatial and temporal regulation and are serving specific functions during embryonic development. Developmental Dynamics 238:2891–2902, 2009. © 2009 Wiley‐Liss, Inc.     

Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography

Purpose: To evaluate and compare the diagnostic accuracy of duplex ultrasound (US) and MR angiography (MRA) at 1.0 T in aortoiliac arterial disease using digital subtraction angiography (DSA) as the reference standard. In addition, a comparison of the 2D time-of flight (TOF) and 3D contrast-enhanced MRA (CE MRA) techniques was performed.Material and Methods: Prospectively, 39 patients with symptoms of lower-extremity arterial occlusive disease were examined using US, TOF MRA, CE MRA and DSA. Significant lesions (stenosis ≥50%) and occlusions were evaluated blindly for each method.Results: For all segments, the sensitivity for US, TOF MRA and CE MRA with regard to significant lesions was 0.72, 0.81 and 0.81, respectively, and the specificity for each was 0.97, 0.91 and 0.92, respectively. For significant lesions above the inguinal ligament the corresponding sensitivity was 0.84, 0.89 and 0.94 and the specificity 0.93, 0.82 and 0.73, respectively. The specificity was higher when the two MRA methods were combined. TOF MRA overgraded 7 segments as occluded. In most cases, the length of the occlusions was correctly determined on CE MRA, overestimated on TOF MRA and uncertain on US.Conclusion: Neither US nor MRA were sufficiently accurate to fully replace angiography. MRA was preferable to US as a non-invasive test when vascular intervention was contemplated. Although CE MRA was superior to TOF MRA, the most accurate results were achieved when the two methods were combined.     

Diagnosis of meningeoma. A comparison of costs before CT, during CT and after introduction of MR imaging

Objective: To assess whether the capital investment required by advances in radiological technology is offset by savings in the direct costs of diagnostic services.Material and Methods: Meningeoma was used as an indicator case. All meningeoma patients from three study periods were included: Twenty patients in 1976-77 before the introduction of CT, 22 patients in 1984-85 when CT was used and 16 patients in 1992 when MR imaging had replaced CT as the most informative imaging modality. Radiological and other diagnostic investigations, and the hospital stay were identified and cost analyzed.Results: The costs of radiological examinations increased from 293 Euros in 1976-77 to 513 Euros in 1992. The average number of diagnostic examinations per patient decreased from 5.1 in 1976-77 to 2.4 in 1992. The length of hospital stay decreased from 11.5 to 2.7 days and the total costs of the diagnostic work-up decreased to one-third of the original, i.e. from 3423 Euros in 1976-77 to 1282 Euros in 1992.Conclusion: The costs of the radiological examinations rose, but the development of radiological technology simplified the diagnostic practice. The hospital stay drastically decreased. The total costs of diagnostic work-up per patient dropped to one-third of the baseline costs.     

Dynamic MR imaging of liver metastases with Gd-EOB-DTPA

Purpose: To assess liver and lesion enhancements by dynamic MR imaging after bolus injection of the hepatobiliary contrast agent gadolinium ethoxybenzyldiethylenetriamine-pentaacetic acid (Gd-EOB-DTPA) in patients with liver metastases and to compare the effect of different doses.Material and Methods: A randomized double-blinded trial with doses of 12.5, 25 and 50 μmol/kg Gd-EOB-DTPA was performed in 35 patients with liver metastases. Liver enhancement, tumor enhancement and liver lesion contrast-to-noise (C/N) ratios were calculated from breath-hold gradient echo images (100/5/80°) recorded precontrast and at different times up to 10 min postcontrast.Results: Normal liver showed a characteristic enhancement pattern, with a rapid enhancement in the first 45 s postcontrast and a slight but significant further increase up to 600 s. The initial enhancement in the lesions was also pronounced, but the enhancement was slightly decreased after 240 s postcontrast. At dose levels of 12.5 and 25 μmol/kg Gd-EOB-DTPA, C/N ratios significantly increased compared to baseline from 90 to 600 s. Postcontrast C/N-values obtained using 50 μmol/kg Gd-EOB-DTPA were not significantly increased, except for the examinations 480 s postcontrast.Conclusion: In liver metastases, C/N ratios obtained with doses of 12.5 and 25 μmol/kg Gd-EOB-DTPA were slightly superior to 50 μmol/kg Gd-EOB-DTPA. This finding is probably due to a more pronounced extracellular effect of the contrast medium at higher doses.     

MR cholangiography in massive hepatobiliary ascariasis. A case report

The ultrasonographic and MR cholangiographic findings in a patient with massive hepatobiliary ascariasis are described.     

Evaluation of pleural disease using MR and CT. With special reference to malignant pleural mesothelioma

Purpose: To evaluate MR imaging and CT in differentiating malignant pleural mesothelioma from other malignancies or benign pleural disease.Material and Methods: Thirty-four patients (18 pleural mesotheliomas, 9 other malignancies, 7 benign pleural diseases) were examined using enhanced CT and MR. Two radiologists reviewed the CT and two others the MR images. Comparisons were made between the diagnostic groups and the imaging methods.Results: The abnormalities commonly found in malignant disease, but significantly less frequently in benign pleural disease, were focal thickening and enhancement of interlobar fissures. In mesothelioma, enhancement of interlobar fissures, tumour invasion of the diaphragm, mediastinal soft tissue or chest wall, were significantly more often observed than in other malignancies and MR was the most sensitive method. In other malignancies, invasion of bony structures was a more common finding and was also better shown by MR. The contrast-enhanced T1 fat-suppressed (CET1fs) sequence detected these features better than other MR sequences.Conclusion: MR, especially the CET1fs sequence in three planes, gave more information than enhanced CT. Focal thickening and enhancement of interlobar fissures were early abnormalities indicating malignant pleural disease. MR could be clinically useful for differentiating mesothelioma from other pleural diseases.     

Contrast-enhanced T1-weighted black-blood fast spin-echo MR imaging of the brain. Technique for suppression of enhancing venous signal

Purpose: Contrast-enhanced T1-weighted black-blood fast spin-echo MR imaging (BB-FSE) was performed to suppress enhancing venous signal and flow artifacts in the brain without sacrificing the T1-weighted imaging contrast.Material and Methods: Twenty-five MR imaging sections (17 transverse and 8 coronal images) in 15 patients with various brain diseases were obtained by contrast-enhanced T1-weighted SE and BB-FSE images.Results: In contrast-enhanced T1-weighted BB-FSE images, venous signal was significantly less and T1-weighted contrast of the brain was more evident. No differences in flow artifacts were found between the two imaging techniques. The interobserver agreements were good for the venous signal and flow artifacts using both techniques.Conclusion: Contrast-enhanced T1-weighted BB-FSE imaging reduced the venous signal in the brain with maintaining T1-weighted contrast. This novel MR technique can be used when the suppression of enhancing venous signal is expected to improve the depiction of enhancing lesions in the brain.