Clinicoradiological features associated with epidermal growth factor receptor exon 19 and 21 mutation in lung adenocarcinoma

AIM

To retrospectively identify clinicopathological and radiological characteristics that could be independent predictors of epidermal growth factor receptor (EGFR) exon 19 and 21 mutation in surgically resected lung adenocarcinomas in a cohort of Asian patients.

MATERIALS AND METHODS

Demographics, histopathology data, and preoperative chest computed tomography (CT) images were evaluated retrospectively in 471 surgically resected lung adenocarcinomas. A total of 24 CT descriptors were assessed. Univariate analyses and multivariate logistic regression analyses were performed to identify independent predicted factors of harbouring EGFR mutations.

RESULTS

EGFR mutations were existed in 252 (53.5%) of 471 patients, and associated with 11 clinicoradiological features. For the model with both clinical and radiological features, the independent predictors of harbouring EGFR mutation were small maximum diameter (≤3.9 cm), non-smokers, micropapillary pattern, pleural retraction, vascular convergence, and absence of solid pattern. The area under the receiver operating characteristic (ROC) curve (AUC) was 0.784. Multivariable logistic regression analysis indicated that non-smokers, vascular convergence, and absence of solid pattern were important independent predictors of EGFR exon 19 mutation, while non-smokers and vascular convergence were independent predictors of EGFR exon 21 mutation. The AUCs were 0.807 and 0.794, respectively. A lepidic growth pattern appeared more frequently in exon 21 mutant tumours than in exon 19 mutant group (p<0.001).

CONCLUSION

CT imaging features of lung adenocarcinomas in combination with clinical variables could be used to prognosticate EGFR mutation status. The separate analysis of EGFR exon 19 or 21 mutation could further improve diagnostic performance.

RNAi in the striped stem borer, Chilo suppressalis, establishes a functional role for aminopeptidase N in Cry1Ab intoxication

The striped stem borer, Chilo suppressalis, is a major target pest of transgenic rice expressing the Cry1Ab protein from the bacterium Bacillus thuringiensis (Bt) in China. Evolution of resistance in this pest is a major threat to the durability of Bt rice. Since Bt exerts its activity through binding to specific receptors in the midgut of target insects, identification of functional Cry1Ab receptors in the midgut of C. suppressalis larvae is crucial to evaluate potential resistance mechanisms and develop effective strategies for delaying insect resistance. In this work, we identified the putative Cry1Ab toxin-binding protein, aminopeptidase-N (APN), in the midgut of C. suppressalis by ligand blot and mass spectrometry. After cloning the full-length cDNAs encoding APN isoforms from the C. suppressalis larval midgut, we studied their spatiotemporal expression in different gut tissues and developmental stages. Furthermore, RNA interference (RNAi) against C. suppressalis aminopeptidases (CsAPNs) was employed to illustrate a functional role for CsAPNs in Cry1Ab toxicity to C. suppressalis larvae using injection and oral delivery of Stealth™ siRNA. Down-regulating the expression of CsAPNs by RNAi was closely associated with reduced susceptibility of C. suppressalis to Cry1Ab. These data provide the first direct evidence that CsAPNs participate in the mode of Cry1Ab action and may act as the functional receptor of Cry1A in C. suppressalis larvae.

Fine structure characterization of martensite/austenite constituent in low-carbon low-alloy steel by transmission electron forward scatter diffraction

Transmission electron forward scatter diffraction and other characterization techniques were used to investigate the fine structure and the variant relationship of the martensite/austenite (M/A) constituent of the granular bainite in low-carbon low-alloy steel. The results demonstrated that the M/A constituents were distributed in clusters throughout the bainitic ferrite. Lath martensite was the main component of the M/A constituent, where the relationship between the martensite variants was consistent with the Nishiyama-Wassermann orientation relationship and only three variants were found in the M/A constituent, suggesting that the variants had formed in the M/A constituent according to a specific mechanism. Furthermore, the Σ3 boundaries in the M/A constituent were much longer than their counterparts in the bainitic ferrite region. The results indicate that transmission electron forward scatter diffraction is an effective method of crystallographic analysis for nanolaths in M/A constituents.

[Gene typing and antibiotic resistance of methicillin-resistant Staphylococcus aureus isolated from lower respiratory tract at two hospitals in Shanghai]

OBJECTIVE

To study the genotyping characteristics and antibiotic resistance of methicillin-resistant Staphylococcus aureus(MRSA) isolated from lower respiratory tract at 2 different level hospitals in Shanghai.

METHODS

The subjects included 155 patients at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014, including 108 males and 47 females, with a mean age of 67.8±16.5. The 155 MRSA strains were isolated from lower respiratory tract specimens and multilocus sequence typing (MLST) and spa typing were analyzed by the PCR method. The antimicrobial resistance of MRSA was tested by VITEK-32. Fisher's exact test was used for statistical analysis.

RESULTS

Among the 155 strains, 28 MLST-spa molecular types were identified, of which ST764-t002(41.29%), ST239-t037(17.42%) and ST239-t030(10.32%) were the most predominant types. The MRSA strains were susceptible to linezolid, vancomycin and teicoplanin, and also had a lower resistance to trimethoprim-sulfamethoxazole and rifampin, with a susceptible rate of 83.9% and 83.2% respectively, but were highly resistant to other antibiotics. The resistance rate of ST239-t037 to trimethoprim-sulfamethoxazole was higher than that of other types, and the resistance rate of ST239-t030 to rifampin was higher than that of other types, the differences being significant(P<0.001). The mean length of hospital stay of the 155 patients was (97±84) days, and mechanical ventilation were used in 78(50.3%) patients, while 108(69.7%))patients received invasive procedures. Broad-spectrum antibiotics were used in 136 (87.1%) patients. There were differences in age, hospitalization days, smoking history, history of COPD, mechanical ventilation, and operation between the 2 hospitals(P<0.05).

CONCLUSION

Most of the MRSA strains at Ruijin Hospital and Tongren Hospital between January 2013 and June 2014 were multi-drug resistant, and the susceptibility spectrum of different genotypes was different.

Detection of aminoglycoside resistance related genes in multidrug-resistant Acinetobacter baumannii isolated from a single institute of Shanghai, China

AIM

Aminoglycoside resistance is common in Acinetobacter baumannii. We investigated aminoglycoside resistance genes in clinical multidrug-resistant Acinetobacter baumannii strains isolated from the Chinese population.

METHODS

One-hundred-and-seven strains of multidrug-resistant Acinetobacter baumannii were isolated from Ruijin Hospital in Shanghai, China. The minimum inhibitory concentrations (MICs) of amikacin, kanamycin, tobramycin, gentamicin, netilmicin and neomycin for these strains were determined with agar dilution method. 16S rRNA methylase genes and eight aminoglycoside modifying enzyme genes were tested via polymerase chain reaction.

RESULTS

We found MICs of amikacin, kanamycin, tobramycin, gentamicin, netilmicin and neomycin in these strains with doses of ≥64 μg/mL, ≥64 μg/mL, ≥128 μg/mL, ≥128 μg/mL, ≥32 μg/mL and ≥8 μg/mL, respectively. Most of those strains showed a high-level resistance to aminoglycosides. ArmA was found in 90% (97/107) of the strains. Six modifying enzyme genes, including aac(6')-Ib, aac(6')-II, aac(3)-II, aac(3)-I, aph(3')-I and ant(3")-I were found with a positive rate of 47%, 50%, 28%, 31%, 93% and 96%, respectively.

CONCLUSION

Multidrug-resistant Acinetobacter baumannii is highly resistant to aminoglycosides. Resistant genes could coexist in one strain, therefore, strict implementation of infection control measures is essential to avoid the rapid spread or outbreaks of these multidrug-resistant Acinetobacter baumannii in healthcare-associated facilities.

Baseline susceptibility of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae) to Bacillus thuringiensis toxins in China

Geographic variability in susceptibility of field-collected Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae) to Bacillus thuringiensis (Berliner) was studied to establish a geographic baseline for comparison of future population responses to the increased use of B. thuringiensis-based insect control products. Colonies of C. medinalis were established from 10 populations collected from 10 different provinces in the major rice (Oryza savita L.)-growing regions of China. Populations were evaluated for their susceptibility to Cry1Ac and Cry1Ab endotoxin proteins with the leaf-dip bioassay. The LC50 values to Cry1Ac and Cry1Ab were estimated for the 10 populations. Bioassay results indicated that the ranges of LC50 in the second instars of C. medinalis to Cry1Ac and Cry1Ab were from 3.77 to 208.22 mg ([AI])/liter and 0.22-7.05 mg ([AI])/liter, respectively. The relative ratios in susceptibility between the most susceptible and the most tolerant populations were beyond 50-fold for Cry1Ac and 30-fold for Cry1Ab. Moreover, there was a significant positive correlation between susceptibilities to the two toxins tested, suggesting that insect populations that are relatively tolerant to one protein are also relatively tolerant to the other.