Generation of LexA enhancer-trap lines in Drosophila by an international scholastic network

Conditional gene regulation in Drosophila through binary expression systems like the LexA-LexAop system provides a superb tool for investigating gene and tissue function. To increase the availability of defined LexA enhancer trap insertions, we present molecular, genetic, and tissue expression studies of 301 novel Stan-X LexA enhancer traps derived from mobilization of the index SX4 line. This includes insertions into distinct loci on the X, II, and III chromosomes that were not previously associated with enhancer traps or targeted LexA constructs, an insertion into ptc, and seventeen insertions into natural transposons. A subset of enhancer traps was expressed in CNS neurons known to produce and secrete insulin, an essential regulator of growth, development, and metabolism. Fly lines described here were generated and characterized through studies by students and teachers in an international network of genetics classes at public, independent high schools, and universities serving a diversity of students, including those underrepresented in science. Thus, a unique partnership between secondary schools and university-based programs has produced and characterized novel resources in Drosophila, establishing instructional paradigms devoted to unscripted experimental science.

Comparison of a 1064-nm neodymium-doped yttrium aluminum garnet picosecond laser using a diffractive optical element vs. a nonablative 1550-nm erbium-glass laser for the treatment of facial acne scarring in Asian patients: a 17-week prospective, randomized, split-face, controlled trial

BACKGROUND

Novel picosecond lasers using a diffractive optical element (P-DOE) have been available for skin resurfacing with distinct mechanisms. However, there are limited data directly comparing P-DOE and conventional fractional lasers for the treatment of atrophic acne scarring.

OBJECTIVES

We sought to compare the efficacy and safety of a 1064-nm neodymium-doped yttrium aluminium garnet P-DOE and a non-ablative fractional laser (NAFL) in the treatment of acne scarring.

METHODS

A prospective, randomized, split-face, controlled trial was performed. One randomly assigned half-side of each patient's face (n = 25) was treated with four consecutive sessions of P-DOE at 3-week intervals and the other side with NAFL, with subsequent follow-up for 8 weeks after the final sessions. The efficacy and safety of the two lasers were determined by the Echelle d'Evaluation Clinique des Cicatrices d'acné (Scale of Clinical Evaluation of Acne Scars; ECCA) grading scale, Investigator's Global Assessment (IGA) score and patients' reports at the final visit. Histologic analysis was also performed.

RESULTS

The P-DOE-treated side achieved a significantly better improvement in acne appearance (ECCA per cent reduction: 55% vs. 42%) with less severe pain (4.3 vs. 5.6) (P < 0.05). The IGA score and subjective satisfaction were consistent with ECCA score results. Occurrences of treatment-related side-effects were also lower in the group treated with P-DOE (P < 0.05). Histologic analysis revealed elongation and increased density of neocollagen fibres, elastic fibres and mucin throughout the dermis from both sides.

CONCLUSIONS

Compared with NAFL, P-DOE afforded better clinical outcomes and fewer side-effects in the treatment of acne scarring in Asian patients.

A method for freeze-fracture and scanning electron microscopy of isolated mitochondria

Electron microscopy as a methodology for the study of mitochondria based on morphological features is a standard technique that has experienced little evolution over the course of several decades. This technology has identified heterogeneity of mitochondria populations across both whole tissues, as well between individual cells, using primarily ultrathin sections for transmission electron microscopy (TEM). However, this technique constrains the evaluation of a sample to a single two-dimensional plane. To overcome this limitation, scanning electron microscopy (SEM) has been successfully utilized to observe three-dimensional mitochondria structures within the complex microenvironment containing total cellular components. In response to these dual technical caveats of existing electron microscopy protocols, we developed a methodology to evaluate the three-dimensional ultrastructure of isolated mitochondria, utilizing a freeze-fracture step and rigorous preservation of sample morphology. This protocol allows for a more high-throughput analysis of mitochondria populations from a specimen of interest, as the sample has been previously purified, as well as a finer resolution of complex intra-mitochondrial structures, using the depth of field created by SEM.

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Protocol designed for SEM of isolated mitochondria samples.

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SEM visualizes mitochondria ultrastructure in 3-D.

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Freeze-fracture creates cross-sectional plane for view of interior organelle structures.

Predictors of adjuvant treatment for pancreatic adenocarcinoma at the population level

BACKGROUND

In the present study, we aimed to describe, at the population level, patterns of adjuvant treatment use after curative-intent resection for pancreatic adenocarcinoma (pcc) and to identify independent predictors of adjuvant treatment use.

METHODS

In this observational cohort study, patients undergoing pcc resection in the province of Ontario (population 13 million) during 2005-2010 were identified using the provincial cancer registry and were linked to administrative databases that include all treatments received and outcomes experienced in the province. Patients were defined as having received chemotherapy (ctx), chemoradiation (crt), or observation (obs). Clinicopathologic factors associated with the use of ctx, crt, or obs were identified by chi-square test. Logistic regression analyses were used to identify independent predictors of adjuvant treatment versus obs, and ctx versus crt.

RESULTS

Of the 397 patients included, 75.3% received adjuvant treatment (27.2% crt, 48.1% ctx) and 24.7% received obs. Within a single-payer health care system with universal coverage of costs for ctx and crt, substantial variation by geographic region was observed. Although the likelihood of receiving adjuvant treatment increased from 2005 to 2010 (p = 0.002), multivariate analysis revealed widespread variation between the treating hospitals (p = 0.001), and even between high-volume hepatopancreatobiliary hospitals (p = 0.0006). Younger age, positive lymph nodes, and positive surgical resection margins predicted an increased likelihood of receiving adjuvant treatment. Among patients receiving adjuvant treatment, positive margins and a low comorbidity burden were associated with crt compared with ctx.

CONCLUSIONS

Interinstitutional medical practice variation contributes significantly to differential patterns in the rate of adjuvant treatment for pcc. Whether such variation is warranted or unwarranted requires further investigation.

Characterization of Staphylococcus aureus faecal isolates associated with food-borne disease in Korea

AIMS

To characterize Staphylococcus aureus faecal isolates from people suspected to be infected with food poisoning by using antimicrobial susceptibility testing and molecular techniques.

METHODS AND RESULTS

A total of 340 Staph. aureus isolates from 6226 people suspected to be infected with food poisoning were identified and characterized by biochemical methods, antimicrobial susceptibility testing and PCR. Samples were obtained from January 2006 to December 2008 from the National Notifiable Diseases Surveillance System at the Research Institute of Public Health and Environment in Seoul Metropolitan, Korea. All strains carried at least one of the eight staphylococcal enterotoxin (se) genes tested and a total of 27 se profiles were produced; the most frequent se profile was seg-sei and the next was sea. Among the total isolates, 36 methicillin-resistant Staphylococcus aureus (MRSAs) isolates were further analysed by multilocus sequence typing (MLST), Staphylococcal cassette chromosome mec (SCCmec) typing, pulsed-field gel electrophoresis (PFGE) and PCR detection for pvl. ST72-SCCmec type IV was the most predominant clone (27 isolates, 75%) followed by ST1-SCCmec type IV (five isolates, 13·8%), ST20-SCCmec type IV (one isolate, 2·8%), ST493-SCCmec type IV (one isolate, 2·8%), ST903-SCCmec type IV (one isolate, 2·8%) and ST5-SCCmec type II (one isolate, 2·8%). By PFGE typing, MRSAs isolated during the same period were grouped together although they were isolated from different regions. None of MRSAs had PVL gene and nine MRSAs were multidrug resistant.

CONCLUSIONS

Analysis of MRSAs by MLST, SCCmec typing, PFGE and pvl detection showed that the majority of strain associated with food-borne diseases belonged to a Korean community-acquired (CA) MRSA clone with ST72-SCCmec type IV-PVL negative-SEG/SEI and its variations while one strain was hospital-acquired (HA) MRSA.

SIGNIFICANCE AND IMPACT OF THE STUDY

CA-MRSA clone which possessed ST72-SCCmec type IV-PVL negative-SEG/SEI was spread most commonly among MRSAs that were associated with food-borne diseases. This is the first report of ST903 strain in Korea.

High fidelity system modeling for high quality image reconstruction in clinical CT

Today, while many researchers focus on the improvement of the regularization term in IR algorithms, they pay less concern to the improvement of the fidelity term. In this paper, we hypothesize that improving the fidelity term will further improve IR image quality in low-dose scanning, which typically causes more noise. The purpose of this paper is to systematically test and examine the role of high-fidelity system models using raw data in the performance of iterative image reconstruction approach minimizing energy functional. We first isolated the fidelity term and analyzed the importance of using focal spot area modeling, flying focal spot location modeling, and active detector area modeling as opposed to just flying focal spot motion. We then compared images using different permutations of all three factors. Next, we tested the ability of the fidelity terms to retain signals upon application of the regularization term with all three factors. We then compared the differences between images generated by the proposed method and Filtered-Back-Projection. Lastly, we compared images of low-dose in vivo data using Filtered-Back-Projection, Iterative Reconstruction in Image Space, and the proposed method using raw data. The initial comparison of difference maps of images constructed showed that the focal spot area model and the active detector area model also have significant impacts on the quality of images produced. Upon application of the regularization term, images generated using all three factors were able to substantially decrease model mismatch error, artifacts, and noise. When the images generated by the proposed method were tested, conspicuity greatly increased, noise standard deviation decreased by 90% in homogeneous regions, and resolution also greatly improved. In conclusion, the improvement of the fidelity term to model clinical scanners is essential to generating higher quality images in low-dose imaging.

The frequency and impact of ROS1 rearrangement on clinical outcomes in never smokers with lung adenocarcinoma

BACKGROUND

To determine the frequency and predictive impact of ROS1 rearrangements on treatment outcomes in never-smoking patients with lung adenocarcinoma.

PATIENTS AND METHODS

We concurrently analyzed ROS1 and ALK rearrangements and mutations in the epidermal growth factor receptor (EGFR), and KRAS in 208 never smokers with lung adenocarcinoma. ROS1 and ALK rearrangements were identified by fluorescent in situ hybridization.

RESULTS

Of 208 tumors screened, 7 (3.4%) were ROS1 rearranged, and 15 (7.2%) were ALK-rearranged. CD74-ROS1 fusions were identified in two patients using reverse transcriptase-polymerase chain reaction. The frequency of ROS1 rearrangement was 5.7% (6 of 105) among EGFR/KRAS/ALK-negative patients. Patients with ROS1 rearrangement had a higher objective response rate (ORR; 60.0% versus 8.5%; P = 0.01) and a longer median progression-free survival (PFS; not reached versus 3.3 months; P = 0.008) to pemetrexed than those without ROS1/ALK rearrangement. The PFS to EGFR-tyrosine kinase inhibitors in patients harboring ROS1 rearrangement was shorter than those without ROS1/ALK rearrangement (2.5 versus 7.8 months; P = 0.01).

CONCLUSIONS

The frequency of ROS1 rearrangements in clinically selected patients is higher than that reported for unselected patients, suggesting that ROS1 rearrangement is a druggable target in East-Asian never smokers with lung adenocarcinoma. Given the different treatment outcomes to conventional therapies and availability of ROS1 inhibitors, identification of ROS1 rearrangement can lead to successful treatment in ROS1-rearranged lung adenocarcinomas.

SU-E-J-01: Analysis of Acquisition Parameters That Caused Artifacts in Four-Dimensional (4D) CT Images of Targets Undergoing Regular Motion

PURPOSE

The aim of this study was to clarify the impacts of acquisition parameters on artifacts in four-dimensional computed tomography (4D CT) images, such as the partial volume effect (PVE), partial projection effect (PPE), and mis-matching of initial motion phases between adjacent beds (MMimph) in cine mode scanning.

METHODS

A thoracic phantom and two cylindrical phantoms (2 cm diameter and heights of 0.5 cm for No. 1 and 10 cm for No.2) were scanned using 4D CT. For the thoracic phantom, acquisition was started automatically in the first scan with 5 sec and 8 sec of gantry rotation, thereby allowing a different phase at the initial projection of each bed. In the second scan, the initial projection at each bed was manually synchronized with the inhalation phase to minimize the MMimph. The third scan was intentionally un-synchronized with the inhalation phase. In the cylindrical phantom scan, one bed (2 cm) and three beds (6 cm) were used for 2 and 6 sec motion periods. Measured target volume to true volume ratios (MsTrueV) were computed. The relationships among MMimph, MsTrueV, and velocity were investigated.

RESULTS

In the thoracic phantom, shorter gantry rotation provided more precise volume and was highly correlated with velocity when MMimph was minimal. MMimph reduced the correlation. For moving cylinder No. 1, MsTrueV was correlated with velocity, but the larger MMimph for 2 sec of motion removed the correlation. The volume of No. 2 was similar to the static volume due to the small PVE, PPE, and MMimph.

CONCLUSIONS

Smaller target velocity and faster gantry rotation resulted in a more accurate volume description. The MMimph was the main parameter weakening the correlation between MsTrueV and velocity. Without reducing the MMimph, controlling target velocity and gantry rotation will not guarantee accurate image presentation given current 4D CT technology.

The superficial medial collateral ligament reconstruction of the knee: effect of altering graft length on knee kinematics and stability

PURPOSE

The purpose of this study was to evaluate and compare the resulting knee kinematics and stability of an anatomic superficial MCL (sMCL) reconstruction and a non-anatomic sMCL reconstruction.

METHODS

In a cadaveric model, normal knee stability and kinematics were compared with sMCL deficient knees and with two experimental sMCL reconstructions. The first reconstruction (AnatRecon) attempted to anatomically reconstruct the sMCL. The second reconstruction (ShortRecon) used a shorter graft to mimic the effect of failing to reproduce the anatomic length of the sMCL. Changes in position of the femur with respect to the tibia were measured with an electromagnetic tracking system during simulated active knee extension and during passive knee stability testing in the sMCL intact knee, the sMCL deficient knee, and the two experimental reconstructions.

RESULTS

Simulated active knee extension demonstrated a significant increase in external tibial rotation of ShortRecon compared to AnatRecon between 30° and 80° of knee flexion (mean difference <3.0° over the range of knee flexion angles; P < 0.008), and a significant increase in external tibial rotation of ShortRecon compared to the intact sMCL was found at 60° and 70° of knee flexion (mean difference <2.0°over the range of knee flexion angles; P < 0.008). Passive joint stability testing demonstrated that division of the sMCL produced approximately 6° of valgus laxity at 30° of knee flexion and increased external tibial rotation of approximately 5° at 30°, 9° at 60°, and 10° at 90° of knee flexion, respectively. AnatRecon restored normal knee kinematics and stability. Additionally, passive stability testing demonstrated a significant increase in external tibial rotation of ShortRecon compared to AnatRecon at 60° (mean difference = 3.7°; P < 0.05) and 90° of knee flexion (mean difference = 4.9°; P < 0.05).

CONCLUSION

Anatomic reconstruction of the sMCL effectively restored knee kinematics and stability in the sMCL deficient knee. Altering the normal ligament length resulted in measurable changes in knee kinematics and stability. This study suggests that in cases of chronic valgus knee instability, anatomic sMCL reconstruction would provide better results than non-anatomic sMCL reconstruction.

Efficacy and tolerability of mirtazapine in treating major depressive disorder with anxiety symptoms: an 8-week open-label randomised paroxetine-controlled trial

AIMS

Prominent anxiety symptoms are related to poor clinical course and outcome in major depressive disorder (MDD). The aim of this randomised, open-label, controlled study is to compare the efficacy and tolerability of mirtazapine in the form of orally disintegrating tablets against paroxetine in treating MDD patients with anxiety symptoms.

METHODS

A total of 60 MDD patients with a score above 18 on the Hamilton Anxiety Rating Scale (HARS) were randomly assigned to 8 weeks of fixed dosing treatment with mirtazapine (15-30 mg/day) and paroxetine (10-20 mg/day). Efficacy was primarily assessed with the HARS and with the 17-item Hamilton Depression Rating Scale (HDRS) at weeks 1, 2, 4 and 8 after treatment. Tolerability was assessed from adverse events.

RESULTS

The generalised estimating equations (GEE) models showed that the rates of improvement in HDRS scores from baseline to week 8 were similar between mirtazapine and paroxetine groups. However, patients with mirtazapine exhibited earlier improvement in HARS scores at weeks 1 and 2. Week-by-week GEE models showed that these significant differences in improvement of HARS scores between the two treatment groups were detectable from the first evaluation after the treatment (week 1) and maintained through week 2. There was no difference in the overall frequency of adverse events experienced between the two treatment groups. The most common adverse event in the mirtazapine group was somnolence (n = 8), whereas that in the paroxetine group was gastrointestinal discomfort (n = 9).

CONCLUSIONS

Mirtazapine and paroxetine were equally effective and well tolerated for the depressive symptoms in MDD patients with the high level of anxiety symptoms. Mirtazapine was, however, more effective in reducing the anxiety symptoms than paroxetine in the early weeks of treatment, suggesting that mirtazapine may have an earlier-onset action for the anxiety symptoms in MDD patients.