Structural basis of DNA crossover capture by Escherichia coli DNA gyrase

DNA supercoiling must be precisely regulated by topoisomerases to prevent DNA entanglement. The interaction of type IIA DNA topoisomerases with two DNA molecules, enabling the transport of one duplex through the transient double-stranded break of the other, remains elusive owing to structures derived solely from single linear duplex DNAs lacking topological constraints. Using cryo-electron microscopy, we solved the structure of Escherichia coli DNA gyrase bound to a negatively supercoiled minicircle DNA. We show how DNA gyrase captures a DNA crossover, revealing both conserved molecular grooves that accommodate the DNA helices. Together with molecular tweezer experiments, the structure shows that the DNA crossover is of positive chirality, reconciling the binding step of gyrase-mediated DNA relaxation and supercoiling in a single structure.

Characteristics of Volatile Organic Compounds Emitted from Airport Sources and Their Effects on Ozone Production

In recent years, commercial air transport has increased considerably. However, the compositions and source profiles of volatile organic compounds (VOCs) emitted from aircraft are still not clear. In this study, the characteristics of VOCs (including oxygenated VOCs (OVOCs)) emitted from airport sources were measured at Shenzhen Bao'an International Airport. The results showed that the compositions and proportions of VOC species showed significant differences as the aircraft operating state changed. OVOCs were the dominant species and accounted for 63.17%, 58.44%, and 51.60% of the total VOC mass concentration during the taxiing, approach, and take-off stages. Propionaldehyde and acetone were the main OVOCs, and dichloromethane and 1,2-dichloroethane were the main halohydrocarbons. Propane had the highest proportion among all alkanes, while toluene and benzene were the predominant aromatic hydrocarbons. Compared with the source profiles of VOCs from construction machinery, the proportions of halogenated hydrocarbons and alkanes emitted from aircraft were significantly higher, as were those of propionaldehyde and acetone. OVOCs were still the dominant VOC species in aircraft emissions, and their calculated ozone formation potential (OFP) was much higher than that of other VOC species at all stages of aircraft operations. Acetone, propionaldehyde, formaldehyde, acetaldehyde, and ethylene were the greatest contributors to ozone production. This study comprehensively measured the distribution characteristics of VOCs, and its results will aid in the construction of a source profile inventory of VOCs emitted from aircraft sources in real atmospheric environments.

Predicting subsolid pulmonary nodules before percutaneous needle biopsy: a comparison of artificial neural network and biopsy results

AIM

To establish an artificial neural network (ANN) model to predict subsolid nodules (SSNs) before percutaneous core-needle biopsy (PCNB). The results of the two methods were compared to provide guidance on the treatment of SSNs.

MATERIALS AND METHODS

This was a single-centre retrospective study using data from 1,459 SSNs between 2013 and 2021. The ANN was developed using data from patients who underwent surgery following computed tomography (CT) (SFC) and validated using data from patients who underwent surgery following biopsy (SFB). The prediction results of the ANN for the PCNB group and the histopathological results obtained after biopsy were compared with the histopathological results of lung nodules in the same group after surgery. Additionally, the choice of predictors for PCNB was analysed using multivariate analysis.

RESULTS

There was no significant difference between the accuracies of the ANN and PCNB in the SFB group (p=0.086). The sensitivity of PCNB was lower than that of the ANN (p=0.000), but the specificity was higher (p=0.001). PCNB had better diagnostic ability than the ANN. The incidence of precursor lesions and non-neoplastic lesions in the SFB group was lower than that in the SFC group (p=0.000). A history of malignant tumours, size (2-3 cm), volume (>400 cm3) and mean CT value (≥-450 HU) are important factors for selecting PCNB.

CONCLUSIONS

Both ANN and PCNB have comparable accuracy in diagnosing SSNs; however, PCNB has a slightly higher diagnostic ability than ANN. Selecting appropriate patients for PCNB is important for maximising the benefit to SSN patients.

Observation on the aerosol and ozone precursors in suburban areas of Shenzhen and analysis of potential source based on MAX-DOAS

Long-term stereoscopic observations of aerosol, NO₂, and HCHO were carried out at the Yangmeikeng (YMK) site in Shenzhen. Aerosol optical depths and NO₂ vertical column concentration (NO₂ VCD) derived from MAX-DOAS were found to be consistent with other datasets. The total NO₂ VCD values of the site remained low, varying from 2 × 10¹⁵ to 8 × 10¹⁵ mol/cm², while the HCHO VCD was higher than NO₂ VCD, varying from 7 × 10¹⁵ to 11 × 10¹⁵ mol/cm². HCHO VCD was higher from September to early November than that was from mid-late November to December and during February 2021, in contrast, NO₂ VCD did not change much during the same period. In January, NO₂ VCD and HCHO VCD were both fluctuating drastically. High temperature and HCHO level in the YMK site is not only driving the ozone production up but also may be driving up the ozone concentration as well, and the O₃ production regime in the YMK site tends to be NO_x-limited. At various altitudes, backward trajectory clustering analysis and Potential Source Contribution Function (PSCF) were utilized to identify possible NO₂ and HCHO source locations. The results suggested that the Huizhou-Shanwei border and the Daya Bay Sea area were the key potential source locations in the lower (200 m) and middle (500 m) atmosphere (WPSCF > 0.6). The WPSCF value was high at the 1000 m altitude which was closer to the YMK site than the near ground, indicating that the pollution transport capability in the upper atmosphere was limited.

[Characteristics of VOCs and Assessment of Emission Reduction Effect During the Epidemic Lockdown Period in Shenzhen Urban Area]

To prevent disease spreading during the COVID-19 epidemic, Shenzhen adopted lockdown measures in March of 2022. This provided an opportunity to study the response of changes in anthropogenic volatile organic compounds (AVOCs) in Shenzhen to emission reduction and to evaluate the effectiveness of current emission reduction measures. This study analyzed the variety of AVOCs before, during, and after the epidemic lockdown based on the online observation data of pollutants at Lianhua Station in Shenzhen from March 7, 2022 to March 27, 2022. Additionally, the sensitivity of ozone formation and the assessment of the reduction effect of precursors was conducted by an observation based model(OBM). The results showed that:affected by regional influences and the interference of meteorological conditions, the average value of AVOCs in Shenzhen urban areas did not drop significantly during the lockdown period compared to that before the lockdown. However, the peak of AVOCs at the morning peak time under the influence of "sea and land wind" during the epidemic lockdown period dropped by 46% on average compared with that during the non-lockdown period, and the aromatic hydrocarbon component dropped the most by 59%. Additionally, under the influence of continuous easterly wind, or during the accumulation and increase of AVOCs affected by regional transmission, aromatic components also decreased by an average of 25% and 21%, respectively. During the lockdown period of the epidemic in Shenzhen, the O₃ formation in urban areas was still AVOCs-limited. Increasing the emission reduction ratio of AVOCs was the most effective measure to reduce O₃ in the short term. In order to ensure the effectiveness of emission reduction, it was recommended that the coordinated emission reduction ratio of AVOCs and NO_x should be greater than 1:2. It was only possible to enter the downward channel of O₃ if the deep emission reduction was more than 60%. This study revealed that the emission reduction of AVOCs during the morning traffic peak during the epidemic lockdown period was conducive to inhibiting the formation of O₃, whereas the control of NO_x would promote it. Strengthening the control of local aromatic hydrocarbon components during the regional impact process could also significantly reduce O₃ production. At this stage, Shenzhen should strengthen the management and control of industrial solvents, especially to reduce the aromatic hydrocarbon components in the solvent source that have a greater impact on the generation of O₃. Further, Shenzhen should continue to promote the reform of the energy structure of motor vehicles to reduce the emission of VOCs in fuel combustion.

Evaluation and measurement of tropospheric glyoxal retrieved from MAX-DOAS in Shenzhen, China

Glyoxal is one of the representative oxygenated volatile organic compounds in the atmosphere. Its accurate measurement has high significance for the determination of VOC emission sources and the calculation of the global budget of secondary organic aerosol. We investigated the spatio-temporal variation characteristics of glyoxal through observations over a 23-day period. Sensitivity analysis of simulated and actual observed spectra revealed that the accuracy of glyoxal fitting is primarily controlled by the wavelength range selected. Within the range of 420-459 nm, the value calculated using the simulated spectra was 12.3 × 10¹⁴ molecules/cm² lower than the actual value, and the results obtained using the actual spectra included a large number of negative values. Overall, the wavelength range has a far stronger influence than other parameters. The wavelength range of 420-459 nm (excluding 442-450 nm) is the most suitable because it ensures minimal influence from interference components in the same wavelength. Within this range, the calculated value of the simulated spectra is the closest to the actual value, with a deviation of only 0.89 × 10¹⁴ molecules/cm². Therefore, the 420-459 nm range (excluding 442-450 nm) was selected for further observation experiments. The fourth polynomial order was used in DOAS fitting, and constant terms were used to correct the actual spectral offset. In the experiments, the glyoxal slant column density primarily ranged from -4 × 10¹⁵ molecules/cm² to 8 × 10¹⁵ molecules/cm², and the near-ground glyoxal concentration ranged from 0.02 to 0.71 ppb. Regarding the average daily variation cycle, high values of glyoxal were concentrated around noon, which was similar with UVB. This indicates that the formation of CHOCHO was related to the emission of biological VOCs. Glyoxal was concentrated below 500 m and the pollution height began to rise around 09:00 and reached the maximum value around 12:00, after which they declined.

[Pollution Characteristics and Source Analysis of Atmospheric VOCs in the Coastal Background of the Pearl River Delta]

As an important precursor of ozone, volatile organic compounds (VOCs) have attracted much attention. This study analyzed the temporal variation and composition of atmospheric VOCs in the coastal background of the Pearl River Delta, using real-time online monitoring data of VOCs obtained at the Yangmeikeng Ecological Environment Monitoring Station from August 2019 to July 2020. The major sources of VOCs were identified using a receptor model based on the PMF (positive matrix factorization) and HYSPLIT (hybrid single particle Lagrangian integrated trajectory) models. The results showed that the annual mean concentration of anthropogenic VOCs in the coastal background area of the Pearl River Delta was 9.30×10^-9(volume fraction). There was obvious seasonal variation of VOCs in this area, with higher values in autumn and winter and lower values in summer. The coastal background area of the Pearl River Delta exhibited a different diurnal variation pattern to that of cities and other backgrounds. While the peak of VOCs concentration mainly occurred in the morning, from 10:00 to 11:00, concentration remained at a low level during the early morning and after 15:00. Ethylene, propylene, toluene, isopentane, isoprene, m/p-xylene, n-butane, and acetylene were the key species that affected the chemical composition of VOCs. The air masses affecting the coastal background area of the Pearl River Delta were mainly short-distance air masses from elsewhere in the province (25%), ocean air masses (27%), coastal air masses (31%), and inland air masses outside the province (17%). Among them, the average concentration of VOCs was lowest under the influence of ocean air masses, which is mainly affected by the mixed source of ship emissions and aging VOCs, gasoline volatilization, and vehicle emissions. In comparison, the concentration level of VOCs increased by 70.1% to 148.8% under the influence of other air masses. The transmission effects of industrial sources, LNG and LPG volatiles, and petrochemical sources were more prominent. Generally, the atmosphere of coastal background areas was severely affected by anthropogenic pollution, especially by air pollution masses transported from the land, while the impact of pollution by ships near shore and tourist traffic cannot be ignored.

Potential application values of a marine red yeast, Rhodosporidiums sphaerocarpum YLY01, in aquaculture and tail water treatment assessed by the removal of ammonia nitrogen, the inhibition to Vibrio spp., and nutrient composition

In recent years, marine red yeasts have been increasingly used as feed diets for larviculture of aquatic animals mainly due to their rich nutrition and immunopotentiation, however little attention is given to their other probiotic profits. In this study, a marine red yeast strain YLY01 was isolated and purified from farming water and it was identified as a member of Rhodosporidiums sphaerocarpum by the phylogeny based on 18S rDNA sequence. The strain YLY01 could effectively remove ammonia nitrogen from an initial 9.8 mg/L to 1.3 mg/L in 48 h when supplemented with slight yeast extract and glucose in water samples and the removal rate of ammonia nitrogen was up to 86%. Shrimps (Litopenaeus vannamei) in experimental group incubated with the yeast YLY01 exhibited a higher survival rate than those in blank control group and positive control group challenged by Vibrio harveyi, and it manifested that the strain has high biosecurity to at least shrimps. The strain YLY01 could inhibit the growth of Vibrio cells when a small quantity of carbon source was added into farming water. In addition, a nutrition composition assay showed the contents of protein, fatty acids, and total carotenoids of the yeast YLY01 were 30.3%, 3.2%, and 1.2 mg/g of dry cell weight, respectively. All these results indicated that the marine red yeast YLY01 has a great potential to be used as a versatile probiotic in aquaculture and to be developed as a microbial agent for high-ammonia tail water treatment.

Effect of postextubation high-flow nasal cannula therapy on lung recruitment and overdistension in high-risk patient

Background

Postextubation high-flow nasal cannula (HFNC) is used as a support therapy in high-risk patients in ICU. This study aimed to determine the effects of HFNC therapy on lung recruitment and overdistension assessed by electrical impedance tomography (EIT).

Methods

Twenty-four patients who received HFNC within 24 h after extubation were prospectively enrolled in this study. EIT was used to monitor regional lung ventilation distributions at baseline (conventional oxygen therapy) and three flow rate levels of HFNC therapy (20, 40, and 60 L/min). Change of end-expiratory lung impedance (ΔEELI), regional recruitment (recruited-pixels) and overdistension (overdistended-pixels), and lung strain change were determined by EIT. EIT images were equally divided into four ventral-to-dorsal horizontal regions of interest (ROIs 1, 2, 3, and 4). “Overdistension-_{by HFNC}” due to HFNC is defined as an increase of overdistened-pixels > 10 than baseline. Patients were divided into two groups: (1) high potential of recruitment (HPR), recruited-pixels > 10 pixels at 60 L/min than baseline, and (2) low potential of recruitment (LPR), recruited-pixels < 10 pixels at 60 L/min than baseline.

Results

When the flow rate gradually increased from baseline to 60 L/min, a significant and consistent increasing trend of global ΔEELI (%) (p < 0.0001), recruited-pixels (p < 0.001), and overdistended-pixels (p = 0.101) was observed. Moreover, the increase of ΔEELI was mainly distributed in ROI2 (p = 0.001) and ROI3 (p < 0.0001). The HPR group (13/24 patients) had significantly higher recruited-pixels than the LPR group (11/24 patients) at 20, 40, and 60 L/min. There were no significant differences in PaO₂/FiO₂, ΔEELI (%), and overdistention pixels between the two groups. The HPR group had 13 patients in which no one had “overdistension-_{by HFNC}”, and the LPR group had 11 patients in which 4 patients had “overdistension-_{by HFNC}” (0/13 vs. 4/11, p = 0.017).

Conclusions

Using EIT could identify diverse effects of HFNC on lung regional ventilation in postextubation situations. Further study is required to validate using “HFNC effect” based on lung recruitment and overdistension by EIT in clinical practice.

Trial registration

The study was retrospectively registered at www.clinicaltrials.gov (no. NCT04245241).

The chicken gut metagenome and the modulatory effects of plant-derived benzylisoquinoline alkaloids

BACKGROUND

Sub-therapeutic antibiotics are widely used as growth promoters in the poultry industry; however, the resulting antibiotic resistance threatens public health. A plant-derived growth promoter, Macleaya cordata extract (MCE), with effective ingredients of benzylisoquinoline alkaloids, is a potential alternative to antibiotic growth promoters. Altered intestinal microbiota play important roles in growth promotion, but the underlying mechanism remains unknown.

RESULTS

We generated 1.64 terabases of metagenomic data from 495 chicken intestinal digesta samples and constructed a comprehensive chicken gut microbial gene catalog (9.04 million genes), which is also the first gene catalog of an animal's gut microbiome that covers all intestinal compartments. Then, we identified the distinctive characteristics and temporal changes in the foregut and hindgut microbiota. Next, we assessed the impact of MCE on chickens and gut microbiota. Chickens fed with MCE had improved growth performance, and major microbial changes were confined to the foregut, with the predominant role of Lactobacillus being enhanced, and the amino acids, vitamins, and secondary bile acids biosynthesis pathways being upregulated, but lacked the accumulation of antibiotic-resistance genes. In comparison, treatment with chlortetracycline similarly enriched some biosynthesis pathways of nutrients in the foregut microbiota, but elicited an increase in antibiotic-producing bacteria and antibiotic-resistance genes.

CONCLUSION

The reference gene catalog of the chicken gut microbiome is an important supplement to animal gut metagenomes. Metagenomic analysis provides insights into the growth-promoting mechanism of MCE, and underscored the importance of utilizing safe and effective growth promoters.

Complete genomic sequence of the Vibrio alginolyticus bacteriophage Vp670 and characterization of the lysis-related genes, cwlQ and holA

Background

Biocontrol of bacterial pathogens by bacteriophages (phages) represents a promising strategy. Vibrio alginolyticus, a gram-negative bacterium, is a notorious pathogen responsible for the loss of economically important farmed marine animals. To date, few V. alginolyticus phages have been successfully isolated, and only three complete genome sequences of them have been released. The limited available phage resources and poor genomic data hamper research on V. alginolyticus phages and their applications for the biocontrol of V. alginolyticus.

Results

We isolated a phage, Vp670, against the V. alginolyticus strain E06333 and obtained its full genomic sequence. It contains 43,121 nucleotides with a GC content of 43.4%, and codes for 49 predicted open reading frames. Observation by electron microscope combined with phylogenetic analysis of DNA polymerase indicates that Vp670 belongs to the subfamily Autographivirinae in the family Podoviridae. orf3 (designated holA) and orf8 (designated cwlQ) are predicted to encode a holin (HolA) and an endolysin (CwlQ), respectively. Expression of holA alone or coexpression of holA and cwlQ from within arrested the growth of Escherichia coli and V. alginolyticus while the expression of cwlQ alone had no effect on the growth of them. Further observation by transmission electron microscopy revealed that the expression of holA vanished the outer membrane and caused the release of cellular contents of V. alginolyticus and the coexpression of holA and cwlQ directly burst the cells and caused a more drastic release of cellular contents. Expression of cwlQ alone in V. alginolyticus did not cause cytomorphological changes.

Conclusions

Phage Vp670 is a V. alginolyticus phage belonging to the family of Podoviridae. The genome of Vp670 contains a two-component lysis module, which is comprised of holA and cwlQ. holA is predicted to encode for the holin protein, HolA, and cwlQ is predicted to encode for the endolysin protein, CwlQ. Both holA and cwlQ likely play important roles during the release of phage progeny.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5131-x) contains supplementary material, which is available to authorized users.

A fibrinogen-related protein, LvFREP2, from Litopenaeus vannamei facilitates the clearance of Vibrio harveyi

Fibrinogen-related proteins (FREPs) play a crucial role in invertebrate immune response. In this study, we acquired a novel fibrinogen-related protein gene in Litopenaeus vannamei coding for one kind of fibrinogen-related protein, designated as LvFREP2. The complete cDNA sequence of LvFREP2 was 1903 bp long, containing an open reading frame of 1479 bp coding for LvFREP2. The LvFREP2 protein contained a putative signal peptide and a fibrinogen-related protein domain. qRT-PCRs indicated that LvFREP2 mRNA ubiquitously distributed in all examined tissues, and it was up-regulated in gills after V. harveyi and LPS challenges. The recombinant LvFREP2 agglutinated Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Vibrio alginolyticus, V. cholerae, V. vulnificus, V. parahaemolyticus, V. harveyi, Pseudomonas aeruginosa, P. fluorescens) in a calcium-dependent manner. LvFREP2 also facilitated the clearance of Vibrio harveyi in vivo. Therefore, our results suggested that lvFREP2 may have important roles in the anti-bacterial immunity of L. vannamei.

A new L-type lectin (LvLTLC1) from the shrimp Litopenaeus vannamei facilitates the clearance of Vibrio harveyi

According to structures and functions of lectins found in shrimp, they are classified into seven types, namely, L-type, C-type, P-type, M-type, galectins, fibrinogen-like domain lectins, and calnexin/calreticulin. Until now, the researches of shrimp lectins are mainly focused on C-type lectins. In this study, we identified a new L-type lectin, designated as LvLTLC1, from the shrimp Litopenaeus vannamei. The cDNA of LvLTLC1 is 1184 bp with an open reading frame of 990 bp encoding a protein of 329 amino acids. The LvLTLC1 protein contained a putative signal peptide, an L-type lectin-like domain, and a transmembrane helix region. Phylogenetic analysis showed that LvLTLC1 belonged to VIP36-like family. LvLTLC1 was expressed in all examined tissues but had higher expression level in gills and hepatopancreas than other tissues. LvLTLC1 expression was up-regulated after immune challenge by Vibrio harveyi and lipopolysaccharide. The recombinant LvLTLC1 agglutinated Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (V. harveyi, V. parahaemolyticus, V. alginolyticus, V. cholerae, V. vulnificus, Pseudomonas aeruginosa, P. fluorescens) in a calcium-independent manner. Recombinant LvLTLC1 exerted the ability of enhancing the clearance of V. harveyi injected in shrimp. Our results indicated that LvLTLC1 functions in anti-pathogen innate immunity of shrimp.

A population-based assessment of primary care visits during adjuvant chemotherapy for breast cancer

BACKGROUND

We used administrative health data to explore the impact of primary care physician (pcp) visits on acute-care service utilization by women receiving adjuvant chemotherapy for early-stage breast cancer (ebc).

METHODS

Our population-based retrospective cohort study examined pcp visits and acute-care use [defined as an emergency room (er) visit or hospitalization] by women diagnosed with ebc between 2007 and 2009 and treated with adjuvant chemotherapy. Multivariate regression analysis was used to identify the effect of pcp visits on the likelihood of experiencing an acute-care visit.

RESULTS

Patients receiving chemotherapy visited a pcp significantly more frequently than they had before their diagnosis [relative risk (rr): 1.48; 95% confidence interval (ci): 1.44 to 1.53; p < 0.001] and significantly more frequently than control subjects without cancer (rr: 1.51; 95% ci: 1.46 to 1.57; p < 0.001). More than one third of pcp visits by chemotherapy patients were related to breast cancer or chemotherapy-related side effects. In adjusted multivariate analyses, the likelihood of experiencing an er visit or hospitalization increased in the days immediately after a pcp visit (rr: 1.92; 95% ci: 1.76 to 2.10; p < 0.001).

CONCLUSIONS

During chemotherapy treatment, patients visited their pcp more frequently than control subjects did, and they visited for reasons related to their breast cancer or to chemotherapy-related side effects. Visits to a pcp by patients receiving chemotherapy were associated with an increased frequency of er visits or hospitalizations in the days immediately after the pcp visit. Those results suggest an opportunity to institute measures for early detection and intervention in chemotherapy side effects.

A centrally generated primary care physician audit report does not improve colonoscopy uptake after a positive result on a fecal occult blood test in Ontario's ColonCancerCheck program

BACKGROUND

Timely follow-up of fecal occult blood screening with colonoscopy is essential for achieving colorectal cancer mortality reduction. In the present study, we evaluated the effectiveness of centrally generated, physician-targeted audit and feedback to improve colonoscopy uptake after a positive fecal occult blood test (fobt) result within Ontario's population-wide ColonCancerCheck Program.

METHODS

This prospective cohort study used data sets from Ontario's ColonCancerCheck Program (2008-2011) that were linked to provincial administrative health databases. Cox proportional hazards regression was used to estimate the effect of centralized, physician-targeted audit and feedback on colonoscopy uptake in an Ontario-wide fobt-positive cohort.

RESULTS

A mailed physician audit and feedback report identifying individuals outstanding for colonoscopy for 3 or more months after a positive fobt result did not increase the likelihood of colonoscopy uptake (hazard ratio: 0.95; 95% confidence interval: 0.79 to 1.13). Duration of positive fobt status was strongly inversely associated with the hazard of follow-up colonoscopy (p for linear trend: <0.001).

CONCLUSIONS

In a large population-wide setting, centralized tracking in the form of physician-targeted mailed audit and feedback reports does not improve colonoscopy uptake for screening participants with a positive fobt result outstanding for 3 or more months. Mailed physician-targeted screening audit and feedback reports alone are unlikely to improve compliance with follow-up colonoscopy in Ontario. Other interventions such as physician audits or automatic referrals, demonstrated to be effective in other jurisdictions, might be warranted.

Assessment of Lung Recruitment by Electrical Impedance Tomography and Oxygenation in ARDS Patients

We hypothesized that not all patients with appreciably recruited lung tissue during a recruitment maneuver (RM) show significant improvement of oxygenation. In the present study, we combined electrical impedance tomography (EIT) with oxygenation measurements to examine the discrepancies of lung ventilation and perfusion versus oxygenation after RM.A 2-minute RM (20 cm H2O positive end-expiratory pressure [PEEP] + 20 cm H2O pressure control) was prospectively conducted in 20 acute respiratory distress syndrome patients from January 2014 to December 2014. A decremental PEEP trial was performed to select the PEEP level after RM. A positive response to RM was identified as PaO2 + PaCO2 ≥400 mm Hg. Relative differences in the distribution of ventilation and perfusion in the most dependent region of interest (ROI4) were monitored with EIT and denoted as the ventilation-perfusion index.Ten patients were found to be responders and 10 patients to be nonresponders. No significant difference in baseline PaO2/FiO2 was observed between nonresponders and responders. A significantly higher PaO2/FiO2 ratio during RM and higher PEEP set after PEEP titration were recorded in responders. In both responders and nonresponders, the proportion of ventilation distributed in ROI4 compared with the global value was lower than the cardiac-related activity before RM, but this situation was reversed after RM (P < 0.01 in each group). Six out of 10 nonresponders exhibited a remarkable increase in ventilation in ROI4. A significant difference in the relative ventilation-perfusion index was found between the patients with remarkable and insufficient lung tissue reopening in the nonresponder group (P < 0.01).A discrepancy between lung tissue reopening and oxygenation improvement after RM was observed. EIT has the potential to evaluate the efficacy of RM by combining oxygenation measurements.

Phylogenetic studies of two Anas platyrhynchos (Anatini: Anatinae) in Hunan province of China based on complete mitochondrial DNA sequences

In this study, we cloned and sequenced the complete mitochondrial DNAs of Chinese duck, Anas platyrhynchos, population from two different areas of Hunan province in China. The Anas platyrhynchos breed Linwu duck (LW) sample was taken from the Linwu county of Chenzhou city, and the Anas platyrhynchos breed Youxian duck (YX) sample was taken from the Youxian county of Zhuzhou city. The lengths of their complete mitochondrial genome were 16,604 bp (LW) and 16,606 bp (YX), respectively. The organization of the two Anas platyrhynchos breed mitochondrial genomes was similar to those reported from other duck mitochondrial genomes. Phylogenetic analyses using N-J computational algorithms showed that the analyzed species are divided into four major clades: Anatinae, Anserinae, Dendrocygninae and Anseranatidae. Also, the Linwu duck and Youxian duck have highly similar phylogenetic relationship.

Changes in end-tidal CO2 could predict fluid responsiveness in the passive leg raising test but not in the mini-fluid challenge test: A prospective and observational study

OBJECTIVE

The objective is to explore the value of end-tidal carbon dioxide (ETCO2) in replacing cardiac index for evaluating fluid responsiveness during the passive leg raising (PLR) test and mini-fluid challenge (mini-FC).

METHODS

Patients experiencing septic shock and who were on mechanical ventilation in an intensive care unit were divided into responder and nonresponder groups according to whether their cardiac index increased by more than 10% after the FC. Before and after those tests, the changes in ETCO2, central venous pressure, heart rate, mean arterial pressure, pulse pressure, and cardiac output were recorded.

RESULTS

Of the 48 patients in the study, 34 had fluid responsiveness according to the changes in cardiac output or stroke volume. The ΔCI and ΔETCO2 in the responder group were larger than the changes in the nonresponder group during the PLR test (1.1 ± 0.7 vs 0.2 ± 0.4 L/min per square meter, 3.0 ± 3.0 vs 0.5 ± 2.5 mm Hg; P < .05) but not during mini-FC. ΔETCO2 greater than or equal to 5% during the PLR test predicted fluid responsiveness with 93.4% specificity and 75.8% sensitivity in a receiver operating characteristic curve. The area under the curve was 0.849 (95% confidence interval, 0.739-0.930). ΔETCO2 greater than or equal to 3% during the mini-FC predicted fluid responsiveness with 93.4% specificity and 33.3% sensitivity in a receiver operating characteristic curve, and the area under the curve was 0.781 (95% confidence interval, 0.646-0.915).

CONCLUSIONS

The changes in ETCO2 may predict fluid responsiveness during the PLR test in patients with septic shock, but similar results were not found with the mini-FC.

The complete mitochondrial genome of the Wugangtong white goose

Wugangtong white goose is one of the famous native breed in Hunan province of China. In this study, the complete mitochondrial genome sequence of the Wugangtong white goose was reported in Hunan Province first, which was determined through PCR-based method. The total length of the mitogenome is 16,741 bp. It contains the typical structure, including 2 ribosomal RNA genes, 22 transfer RNA genes, 13 protein-coding genes and 1 non-coding control region (D-loop region) as that of most other vertebrates. The overall composition of the mitogenome was estimated to be 30.22% for A, 22.69% for T, 32.02% for C and 15.06% for G. All the protein initiation codons are ATG, except for COX1, COX2 and ND5 are GTG, ND6 is CTA. The complete mitochondrial genome sequence of the Wugangtong white goose will provide an important data set for the study in genetic mechanism of Wugangtong goose in Hunan province.

Impact of socio-economic status on breast cancer screening in women with diabetes: a population-based study

AIMS

There is evidence to suggest that mammography rates are decreased in women with diabetes and in women of lower socio-economic status. Given the strong association between low socio-economic status and diabetes, we explored the extent to which differences in socio-economic status explain lower mammography rates in women with diabetes.

METHODS

A population-based retrospective cohort study in Ontario, Canada, of women aged 50 to 69 years with diabetes between 1999 and 2010 age matched 1:2 to women without diabetes. Main outcome measure is the likelihood of at least one screening mammogram in women with diabetes within a 36-month period, starting as of either 1 January 1999, their 50th birthday, or 2 years after diabetes diagnosis--whichever came last. Outcomes were compared with those in women without diabetes during the same period as their matched counterparts, adjusting for socio-economic status based on neighbourhood income and other demographic and clinical variables.

RESULTS

Of 504,288 women studied (188,759 with diabetes, 315,529 with no diabetes), 63.8% had a screening mammogram. Women with diabetes were significantly less likely to have a mammogram after adjustment for socio-economic status and other factors (odds ratio 0.79, 95% CI 0.78-0.80). Diabetes was associated with lower mammogram use even in women from the highest socio-economic status quintile (odds ratio 0.79, 95% CI 0.75-0.83).

CONCLUSIONS

The presence of diabetes was an independent barrier to breast cancer screening, which was not explained by differences in socio-economic status. Interventions that target patient, provider, and health system factors are needed to improve cancer screening in this population.

Determination and analysis of the complete mitochondrial genome sequence of Wugangtong grey goose

Mitochondrial DNA plays an important role in living organisms. In this study, the complete mitochondrial genome sequence of the Wugangtong grey goose was reported in Human Province first, which was determined through PCR-based method. The total length of the mitogenome is 16,740 bp. It contains the typical structure, including 2 ribosomal RNA genes, 22 transfer RNA genes, 13 protein-coding genes and 1 non-coding control region (D-loop region) as that of most other vertebrates. The overall composition of the mitogenome was estimated to be 30.22% for A, 22.67% for T, 32.05% for C and 15.07% for G. All the protein initiation codons are ATG, except for COX1, COX2 and ND5 are GTG, ND6 is CTA. The complete mitochondrial genome sequence of the Wugangtong grey goose will provides an important data set for the study in genetic mechanism of goose in Hunan province.

Simultaneous picosecond and femtosecond solitons delivered from a nanotube-mode-locked all-fiber laser

We propose a compact nanotube-mode-locked all-fiber laser that can simultaneously generate picosecond and femtosecond solitons at different wavelengths. The pulse durations of picosecond and femtosecond solitons are measured to be ∼10.6  ps and ∼466  fs, respectively. Numerical results agree well with the experimental observations and clearly reveal that the dynamic evolutions of the picosecond and femtosecond solitons are qualitatively distinct in the intracavity. Our study presents a simple, stable, low-cost, and dual-scale ultrafast-pulsed laser source suitable for practical applications in optical communications.

Incidence of diabetes among postmenopausal breast cancer survivors

AIMS/HYPOTHESIS

Evidence is emerging of an association between breast cancer and diabetes; however, it is uncertain whether diabetes incidence is increased in postmenopausal breast cancer survivors compared with women without breast cancer. The objective of this study was to determine whether postmenopausal women who develop breast cancer have a higher incidence of diabetes than those who do not develop breast cancer.

METHODS

We used population-based data from Ontario, Canada to compare the incidence of diabetes among women with breast cancer, aged 55 years or older, from 1996 to 2008, with that of age-matched women without breast cancer. We used Cox proportional hazard models to estimate the effect of breast cancer on the cause-specific hazard of developing diabetes overall and in the subgroup of women who received adjuvant chemotherapy.

RESULTS

Of 24,976 breast cancer survivors and 124,880 controls, 9.7% developed diabetes over a mean follow-up of 5.8 years. The risk of diabetes among breast cancer survivors compared with women without breast cancer began to increase 2 years after diagnosis (HR 1.07 [95% CI, 1.02, 1.12]), and rose to an HR of 1.21 (95% CI, 1.09, 1.35) after 10 years. Among those who received adjuvant chemotherapy (n = 4,404), risk was highest in the first 2 years after diagnosis (HR 1.24 [95% CI 1.12, 1.38]) and then declined.

CONCLUSIONS/INTERPRETATION

We found a modest increase in the incidence of diabetes among postmenopausal breast cancer survivors that varied over time. In most women the risk began to increase 2 years after cancer diagnosis but the highest risk was in the first 2 years in those who received adjuvant therapy. Our study suggests that greater diabetes screening and prevention strategies among breast cancer survivors may be warranted.

P5-18-02: A Population Level Assessment of Emergency Room Visits and Hospitalizations for Women Undergoing Adjuvant Chemotherapy for Early Breast Cancer

Background: Adjuvant chemotherapy is considered the standard of care for women with lymph node positive and high risk lymph node negative breast cancer. While the acute toxicities of chemotherapy are well documented in clinical trials, the frequency of serious treatment related toxicities of adjuvant chemotherapy in the general population is not well described. We undertook a population based assessment of the frequency of serious treatment related toxicity in women undergoing adjuvant chemotherapy for early breast cancer (EBC). Methods: All incident EBC patients diagnosed between January 2007 and December 2008 in Ontario, Canada were identified from the Ontario Cancer Registry. Patient records were linked deterministically to multiple provincial administrative health care databases to provide comprehensive medical follow-up. Exclusion criteria were set to exclude patients on chemotherapy for advanced breast cancer. Any patient with who received at least 1 cycle of adjuvant chemotherapy was included in the analysis. Serious toxicities resulting in emergency room (ER) visits or hospitalizations occurring between the start date of chemotherapy and 30 days after the last dose of chemotherapy were identified. Logistic regression models were used to identify the impact of chemotherapy regimen, age, comorbidity and duration on therapy on the likelihood of experiencing serious toxicity.

Results: Of the 3090 women identified in our cohort, 1440 (46.6%) experienced at least 1 serious toxicity resulting in an ER visit during their adjuvant treatment. Of the ER visits, the majority (1107, 87%) were attributable to treatment related toxicities. Febrile neutropenia (FN) was the most common treatment related toxicity occurring in 27.1% of patients in the cohort. Docetaxel containing regimens were associated with a significantly higher rate of ER visits and FN (54.6%, 34.6%) compared with paclitaxel (38.0%, 17.9%), or anthracycline alone (epirubicin 45.8%, 23.8%; doxorubicin 32.8%, 15.4%). Table 1 displays the impact of clinical and patient factors on multivariable analysis.

Papular dermatitis induced in guinea pigs by the biting midge Culicoides sonorensis (Diptera: Ceratopogonidae)

Histological, ultrastructural, and virological examinations were performed on abdominal skin from guinea pigs after a blood meal by colony-bred biting midges, Culicoides sonorensis. Small, superficial, cutaneous, crateriform ulcers with necrosis of superficial dermis developed at feeding sites and healed within 24-48 hours. Animals developed nonpruritic erythematous papules 5 days after feeding that persisted until the study ended at 12 days after feeding. Papules corresponded histologically to foci of epidermal hyperplasia and superficial interstitial dermatitis with intraepidermal micropustules and scattered intraepidermal polykaryons. The principal ultrastructural changes were spongiosis in germinal epithelium and neutrophilic-histiocytic exocytosis. No viral agents or broken mouthparts were identified in lesions. The dermatitis may represent a host reaction to persisting insect salivary secretion and should be considered as an additional consequence of blood feeding in future studies involving biting midges.

[13-week subchronic oral toxicity study of ammonium sulfate in rats]

A 13-week subchronic oral toxicity study of ammonium sulfate was performed in both sexes of F344 rats by feeding them a CRF-1 powder diet containing concentrations of 0%, 0.38%, 0.75%, 1.5%, and 3.0% of the substance. Rats were randomly divided into 5 groups each consisting of 10 males and 10 females. Male animals in the 3% group exhibited diarrhea during the administration period. No changes indicating obvious ammonium sulfate toxicity were observed in the body weights, organ weights, hematological, serum biochemical, or histopathological examinations. Based on these results, the NOEL (no-observed-effect level) of ammonium sulfate for F344 rats was judged to be 1.5% in males (886 mg/kg/day) and 3% in females (1975 mg/kg/day), and the MTD (maximally tolerated dose) for 2-year carcinogenicity studies in F344 rats was concluded to be 3.0% or more in the diet.

[A 13-week subchronic oral toxicity study of Perilla extracts in F344 rats]

A 13-week subchronic oral toxicity study of Perilla extracts in drinking water containing 0%, 2.5%, 5% and 10% extracts was performed in both sexes of F344 rats. Rats were randomly divided into 4 groups each consisting of 10 males and 10 females. No animals died during the period of administration. There were no treatment-related changes in body weight gain or in hematological or blood biochemistry values. Nor were any treatment-related histopathological changes observed in the highest dose group. These findings indicate that ingestion of 10% Perilla extracts in drinking water for 13-week does not cause any toxicological changes in rats.

Effect of n-butanol on Na+, K+-ATPase

The effect of n-butanol on the activity of Na+, K+-ATPase has been found different at different temperatures. Below the phase-transition temperature, n-butanol has a stimulating effect provided the concentration is not higher than 0.3 M. But if the activity is determined above the phase-transition temperature, n-butanol has an inhibitory effect. The p-nitrophenyl phosphatase activity has been found to be inhibited by n-butanol even at comparatively low temperatures. This is in accord with the finding that the Arrhenius plot for p-nitrophenyl phosphatase did not show any break. It is suggested that at lower temperatures the conformational change involved in the transport of Na+, K+ ions may be the rate-limiting factor in the overall reaction, and n-butanol may be used as a probe for perturbation of the membrane to elucidate the mechanism of Na+, K+-ATPase.