The Interplay Effect and Mitigations with Cyclotron and Linac Proton Beam Scanning for Lung SBRT

PURPOSE/OBJECTIVE(S)

To evaluate the impact of different types of pencil beam scanning proton accelerators and spot sizes on interplay effects, mitigations, and plan quality for lung cancer patients treated with SBRT.

MATERIALS/METHODS

Twenty lung cancer patients (ten peripheral and ten central tumors) treated in our institution with photon SBRT were selected to represent varying tumor volumes and respiratory motion amplitudes for this retrospective study. The respiratory motion amplitude ranged from 0.1 to 1.0 cm with compression. For each patient, plans were created using: 1) cyclotron-generated proton beams (CPB) (σ: 2.7-7.0 mm); 2) linear accelerator proton beams (LPB) (σ: 2.9-5.5 mm); and 3) linear accelerator proton minibeams (LPMB) (σ: 0.9-3.9 mm). Plans were robustly optimized on the GTV using each individual 4DCT phase. Single-filed optimization (SFO) plans were the first attempt, and if the plan quality did not meet the dosimetric requirement, multi-field optimization (MFO) was used. MFO plans were created for all patients for comparison. For each patient, all plans were normalized to have the same dose to 99% of the GTV. Interplay effects were evaluated for ten scenarios of treatment delivery starting in ten breathing phases using machine generic time models and a constant breathing period of 4 seconds. Volumetric repainting (VR) was performed 2-6 times for each plan. To assess plan quality in the nominal scenario, we compared the conformity index (CI), R50, and the percentage of lung volume receiving 20 Gy (RBE) (V20Gy). CI is defined as the ratio of the 100% isodose volume to the GTV. R50 is defined as the 50% isodose volume divided by the GTV. Dmax and V18Gy of the proximal bronchial tree (PBT) were evaluated for central tumors.

RESULTS

Twelve of 20 plans can be optimized sufficiently with SFO. In interplay effect evaluation, the mean V100%RX values of the GTV were 99.42±0.6%, 97.52±3.9%, and 94.49±7.3%for CPB, LPB, and LPMB plans respectively. After VR 2/3/5 times, the V100%RX values were improved (on average) by 0.13%/1.84%/4.63% for CPB/LPB/LPMB plans. The delivery time for VR plans was the lowest for LPB plans, while delivery time for LPMB was on average 1 minute longer than CPB plans. VR showed no effect on lung V20Gy, Dmax and V18Gy of the PBT. SFO plans were more robust against the interplay effect compared with MFO plans for LPB and LPMB. Average CIs of 1.88±0.4, 1.79±0.4, and 1.75±0.4; average R50s of 7.99±4.0, 6.68±3.0, and 5.70±2.6; and average lung V20Gy values of 2.81±1.5, 2.26±1.3, and 1.85±1.1 were obtained for CPB, LPB, and LPMB plans, respectively. Dmax and V18Gy of the PBT decreased with decreasing spot sizes.

CONCLUSION

LPMB, with the smallest spot size, produced superior plan quality. In the absence of VR, proton machines with large spot sizes generated more robust plans against interplay effects. VR improved the plan robustness against interplay effects for modalities with small spot sizes and fast energy changes, preserving the low dose sparing aspect of the LPMB, even when motion is included.

Investigation of the Relationship between Aperture Use for Treating Small and Shallow Brain Lesions in Proton Therapy with Different Spot Size Variations in Three Proton Therapy Systems

PURPOSE/OBJECTIVE(S)

To compare plan quality among standard vs. aperture-based Intensity-Modulated Proton Therapy (IMPT) using cyclotron-generated proton beams (CPB), linear accelerator proton beams (LPB), and linear accelerator proton minibeams (LPMB) for multiple brain metastases.

MATERIALS/METHODS

Fifty-five brain lesions from twenty patients were planned with three different spot size ranges using CPBs (σ: 2.7-7.0 mm) and compared against LPBs (σ: 2.9-5.5 mm), and LPMBs (σ: 0.9-3.9 mm). Apertures with a diameter of 0.3 cm were applied to beams irradiating all tumors < 1 cm3 in volume and any tumor < 2.5 cm depth in the patient and compared against the same patient plans containing no apertures. All plans were optimized with the multi-field optimization (MFO) technique using the Monte Carlo algorithm. Dose coverage to each lesion for each proton plan was set to 99% of the GTV receiving the prescription (Rx) dose for all plans. Robustness with ±2 mm setup uncertainty and ±2% range uncertainty was included in robust evaluation using V100%Rx > 95% of the GTV. Conformity index (CI) and gradient index (GI) were used to analyze the effect of apertures vs. no apertures (standard) for each IMPT plan type. CI was defined as the volume of the 100% isodose line divided by the volume of the GTV + 2 mm expansion to account for robust planning. The Wilcoxon signed rank test was utilized to determine the statistical significance of dosimetric results compared between aperture-based and standard IMPT plans.

RESULTS

When apertures were implemented in the treatment planning for all shallow and small brain lesions, shallow brain tumors showed the most prominent improvement in conformity and gradient index. A 6.7% difference in average conformity was calculated for standard vs. aperture-based plans for LPMBs, followed by a 5.3% improvement for CPBs. Improvement in gradient index for standard vs. aperture-based plans was significant for both shallow and deeper tumors for CPB and LPB plan types, as shown in Table 1 below. CPB and LPB plan gradient indices were statistically significant for comparing aperture-based vs. standard IMPT plans.

CONCLUSION

We successfully quantified plan quality and evaluated results for aperture- vs. standard IMPT plans using CPBs, LPBs, and LPMBs for brain metastases. Plan quality improves the greatest with apertures applied to beams irradiating shallow tumors. Apertures may not be necessary for small, deeper tumors with IMPT.

Dosimetric Risk Estimation of Chest Wall Pain Following 5-Fraction Lung Stereotactic Body Radiotherapy

PURPOSE/OBJECTIVE(S)

Development of chest wall pain (CWP) following lung stereotactic body radiotherapy (SBRT) is a known toxicity, particularly for peripheral lesions. While CW V30 has been most consistently associated with development of post-SBRT CWP, existing series included heterogeneous dose-fractionation regimens, most commonly 48-54 Gy in 3-4 fractions. The present study aims to identify clinical and dosimetric variables associated with development of CWP among patients treated with 5 fraction lung SBRT.

MATERIALS/METHODS

Intradepartmental quality assurance database of SBRT patients was queried to identify lung targets treated to a minimum of 45 Gy in 5 fractions. Retrospective chart and plan reviews were performed on these cases to collect patient, tumor, and treatment-related data, selecting for patients with peripheral lesions (any histology), and recording presence or absence of CWP during or following SBRT. Patients with less than 6 months of post-SBRT clinical follow-up were excluded. The CW was defined as a 2 cm expansion of the ipsilateral lung (inclusive of intercostal musculature, ribs, and superficial soft tissue). Logistic regression analyses were performed on continuous and nominal data to determine statistically significant (p<0.05) correlations between clinical (age, gender, known osteopenia/osteoporosis, diabetes, prior thoracic radiotherapy, lesion distance to CW), treatment (interval of SBRT delivery, dose prescribed), and dosimetric (Dose to 0.1/1/5/10cc; V30, V40) factors with CWP.

RESULTS

Between February 2011 and January 2022, 93 patients were identified for inclusion in the present analysis, treated to 100 total lesions in 99 courses of treatment. Median patient age was 75 years (range 34-90), 48 (52%) were female, and 29 (of 99 treatment courses; 29%) had received prior thoracic radiotherapy. Median SBRT dose was 50 Gy (45-60), delivered over a median of 9 days (4-18). At a median post-SBRT follow-up of 21 months, 11 patients developed CWP at a median of 9 months post-SBRT (0-32). Statistically significant correlations were identified between CWP and known pre-existing osteopenia or osteoporosis, target distance to CW, and CW D0.1cc, D1cc, D5cc, and D10cc, but not CW V30 or V40. Crude risk of CWP for selected clinically practical dose-volume thresholds are presented in Table 1: CONCLUSION: For patients treated with lung SBRT in 5 fractions, dose to CW volume thresholds appears to correlate more closely than V30 or V40 for CWP estimation. Further investigation and validation of optimal CW volume thresholds, as well as integration of pre-existing condition clinical factors in risk estimation, appears warranted.

Small Proteins; Big Questions

In recent years, there has been increased appreciation that a whole category of proteins, small proteins of around 50 amino acids or fewer in length, has been missed by annotation as well as by genetic and biochemical assays. With the increased recognition that small proteins are stable within cells and have regulatory functions, there has been intensified study of these proteins. As a result, important questions about small proteins in bacteria and archaea are coming to the fore. Here, we give an overview of these questions, the initial answers, and the approaches needed to address these questions more fully. More detailed discussions of how small proteins can be identified by ribosome profiling and mass spectrometry approaches are provided by two accompanying reviews (N. Vazquez-Laslop, C. M. Sharma, A. S. Mankin, and A. R. Buskirk, J Bacteriol 204:e00294-21, 2022, https://doi.org/10.1128/JB.00294-21; C. H. Ahrens, J. T. Wade, M. M. Champion, and J. D. Langer, J Bacteriol 204:e00353-21, 2022, https://doi.org/10.1128/JB.00353-21). We are excited by the prospects of new insights and possible therapeutic approaches coming from this emerging field.

Zanidatamab (ZW25) in HER2-expressing gastroesophageal adenocarcinoma (GEA): Results from a phase I study

164

Background: For patients with human epidermal growth factor receptor 2 (HER2)-overexpressing GEA, trastuzumab in combination with chemotherapy is the only approved HER2-targeted therapy, and they have limited treatment options after progression. Zanidatamab, a HER2-targeted bispecific antibody, has shown durable anti-tumor activity with good tolerability in a range of HER2-expressing cancers. Methods: In this 3-part Phase 1 study (NCT02892123), zanidatamab (10 mg/kg QW, 20 mg/kg Q2W, or 30 mg/kg Q3W) is administered as a single agent (Parts 1 & 2; QW or Q2W) or in combination with chemotherapy (Part 3; Q2W or Q3W). Eligibility criteria includes GEA with HER2 expression as assessed by immunohistochemistry (IHC) 3+ or IHC 2+, progression after standard of care therapy, and measurable disease per RECIST 1.1 (Part 2 requirement only). Results: In Parts 1 and 2, 36 GEA patients have been treated with zanidatamab (QW [n = 5]; Q2W [n = 31]). In Part 3, 26 GEA patients have been treated (zanidatamab Q2W + (paclitaxel [n = 11] or capecitabine [n = 6]); zanidatamab Q3W + capecitabine [n = 9]). Conclusions: Zanidatamab, both as a single agent and in combination with chemotherapy, is well tolerated with promising and durable anti-tumor activity in heavily pretreated GEA patients (including prior HER2-targeted therapy). These data support further investigation of zanidatamab as a novel therapeutic for patients with HER2-expressing GEA. Clinical trial information: NCT02892123. [Table: see text]

Zanidatamab (ZW25) in HER2-positive biliary tract cancers (BTCs): Results from a phase I study

299

Background: Treatment options are limited for patients with unresectable, locally advanced or metastatic BTCs progressing after first line treatment. Standard second line chemotherapy yields objective response rates (ORR) of < 10% and median overall survival of these patients is < 6 months. Human epidermal growth factor receptor 2 (HER2) overexpression/ amplification is observed in 5–19% of BTCs. Zanidatamab is a bispecific HER2-targeted antibody that has demonstrated durable single agent activity with good tolerability in a range of HER2-overexpressing cancers. Methods: In the expansion cohort of this phase I study (NCT02892123), the primary objective is to characterize safety and tolerability of zanidatamab and secondary objectives include evaluation of anti-tumor activity. This cohort includes BTC patients with centrally confirmed HER2 overexpression (immunohistochemistry [IHC] 3+ or IHC 2+/ fluorescence in situ hybridization [FISH]+), disease progression after standard of care therapy, and measurable disease per RECIST 1.1. Zanidatamab is administered at the previously identified recommended dose of 20 mg/kg every 2 weeks (Q2W). Tumors are assessed every 8 weeks (response confirmed at ≥ 4 weeks). Results: As of the data cutoff date (Jul 28, 2020), 20 patients (median age: 63 years [range, 42–78]) with BTC (11 gallbladder cancers, 5 intra- and 4 extra-hepatic cholangiocarcinomas) have been treated with zanidatamab. The median number of prior systemic therapies was 2.5 (range, 1–8), including five patients who had received prior HER2-targeted therapy (trastuzumab). Fourteen (70%) patients experienced zanidatamab-related adverse events (AEs), all of which were grade 1 or 2 in severity. The most common (occurring in ≥ 20%) zanidatamab-related AEs were diarrhea (n = 9) and infusion-related reactions (n = 6). A single treatment-related serious AE of grade 2 fatigue was reported in one patient. Among patients evaluable for response (n = 17), the confirmed ORR was 47% (n = 8; 95% confidence interval [CI]: 23, 72), the disease control rate was 65% (n = 11; 95% CI: 38, 86) and the median duration of response was 6.6 months (95% CI: 3.2, not estimable). Conclusions: Zanidatamab is well tolerated with promising and durable anti-tumor activity in patients with HER2 overexpressing BTC. Based on these data, zanidatamab is now being evaluated in an ongoing global Phase 2b study in patients with advanced HER2+ BTC that have progressed after treatment with a gemcitabine-containing regimen (NCT04466891). Clinical trial information: NCT02892123.

Abstract B001: Safety and efficacy of ZW25, a HER2-targeted bispecific antibody, in combination with chemotherapy in patients with locally advanced and/or metastatic HER2-expressing gastroesophageal cancer

Background: Up to 30% of gastroesophageal adenocarcinoma (GEA) overexpress HER2. ZW25 is a novel bispecific antibody that targets HER2 domains ECD2 and ECD4, resulting in multiple differentiated and unique mechanisms of action, including increased antibody binding density and improved receptor internalization and downregulation relative to trastuzumab. In an ongoing phase 1 trial (ZWI-ZW25-101; NCT02892123), single-agent ZW25 was well tolerated and showed promising anti-tumor activity across HER2-expressing solid tumors. This abstract presents data for GEA patients treated with ZW25 in combination with chemotherapy in Study ZWI-ZW25-101. Methods Eligible patients had HER2-expressing (IHC 3+, IHC 2+/FISH+, or IHC 2+/FISH-) GEA and had disease progression after 1–3 lines of prior chemotherapy for advanced and/or metastatic disease. Fresh or archived tumor tissue was required for central review of HER2 status, although patients could be enrolled based on local results. Patients received ZW25 in combination with paclitaxel or capecitabine. Evaluations included standard safety assessments, tumor re-staging (Q8W by RECIST 1.1), and assessment of peak/trough pharmacokinetic (PK) levels during each cycle. Results To date, 14 patients have been enrolled, with safety and efficacy data available for 11. ZW25 was administered in combination with paclitaxel (n=5) or capecitabine (n=6). The median age was 62 yrs (range, 26-80). The median number of prior anti-cancer regimens was 3 and the median number of prior HER2-targeted therapies was 1. Six patients (55%) were HER2 IHC3+ or IHC2+ and FISH+ per central review. The most common adverse events (AEs) considered related to ZW25 or ZW25 and chemotherapy were diarrhea (n=5; 45%), fatigue (n=3; 27%), and nausea (n=3; 27%); the majority of events were Grade 1 or 2. Grade 3 or higher events considered related to ZW25 or ZW25 and chemotherapy occurred in 3 patients (27%), including fatigue, hypokalemia, and neutropenia (n=1 each). One additional patient experienced a Grade 5 serious adverse event of pneumonitis, reported as related to the combination of ZW25 and paclitaxel. This patient had been previously treated with trastuzumab, cisplatin, and capecitabine; pembrolizumab and margetuximab; and most recently DS8201, and had asymptomatic interstitial lung disease at study entry. A total of 9/11 patients (82%) had measurable disease and 8/9 (89%) were response-evaluable. The objective response rate was 63% (95% CI: 25, 92) (5/8 patients; all partial responses, with 4 confirmed to date) and the disease control rate was 75% (6/8 patients). Responses were seen in patients with FISH+ and FISH- disease, as well as in combination with either paclitaxel or capecitabine. Patients have received between 1 and 12 cycles of treatment and 4 patients remain on treatment. PK data will be presented at the meeting. Conclusions The combination of ZW25 with chemotherapy was generally well tolerated in heavily pre-treated patients with HER2 high- and low-expressing GEA and the preliminary anti-tumor activity is promising. Further evaluation of the safety and efficacy of ZW25 in combination with standard of care chemotherapy regimens has been initiated in frontline GEA (ZW25-201; NCT03929666).

Citation Format: Funda Meric-Bernstam, Jorge Chaves, Do-Youn Oh, Jeeyun Lee, Yoon-Koo Kang, Erika Hamilton, Jose Mayordomo, Melody Cobleigh, Christos Vaklavas, Elena Elimova, Jaffer Ajani, Jordi Rodon, Gerry Rowse, Todd Gray, Rose Lai, Diana Hanna. Safety and efficacy of ZW25, a HER2-targeted bispecific antibody, in combination with chemotherapy in patients with locally advanced and/or metastatic HER2-expressing gastroesophageal cancer [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B001. doi:10.1158/1535-7163.TARG-19-B001

Tucatinib Combined With Ado-Trastuzumab Emtansine in Advanced ERBB2/HER2-Positive Metastatic Breast Cancer: A Phase 1b Clinical Trial

Importance

Treatment options for patients with disease progression after treatment with trastuzumab, pertuzumab, and ado-trastuzumab emtansine (T-DM1) are limited. Tucatinib is an oral, potent, human epidermal growth factor receptor 2 (HER2)-specific tyrosine kinase inhibitor (TKI) being developed as a novel treatment for ERBB2/HER2-positive breast cancer.

Objective

To determine the maximum tolerated dosage of tucatinib in combination with T-DM1 in the treatment of patients with ERBB2/HER2-positive metastatic breast cancer with and without brain metastases.

Design, Setting, and Participants

In this phase 1b open-label, multicenter, clinical trial, 57 participants enrolled between January 22, 2014, and June 22, 2015, were 18 years of age or older with ERBB2/HER2-positive metastatic breast cancer previously treated with trastuzumab and a taxane. Data were analyzed between January and March 2018.

Interventions

Tucatinib 300 mg or 350 mg administered orally twice per day for 21 days and T-DM1 3.6 mg/kg administered intravenously once every 21 days.

Main Outcomes and Measures

Safety assessments, pharmacokinetics, and response were assessed using RECIST 1.1 every 2 cycles for 6 cycles, followed by every 3 cycles.

Results

Fifty-seven T-DM1-naive patients (median [IQR] 51 [44.0-63.0] years of age) who had undergone a median of 2 earlier HER2 therapies (range, 1-3) were treated. The tucatinib maximum tolerated dosage was determined to be 300 mg administered twice per day with dose-limiting toxic reactions seen at 350 mg twice per day. Pharmacokinetic analysis showed that there was no drug-drug interaction with T-DM1. Adverse events seen among the 50 patients treated at the maximum tolerated dosage regardless of causality included nausea (36 patients; 72%), diarrhea (30 patients; 60%), fatigue (28 patients; 56%), epistaxis (22 patients; 44%), headache (22 patients; 44%), vomiting (21 patients; 42%), constipation (21 patients; 42%), and decreased appetite (20 patients; 40%); the majority of adverse events were grade 1 or 2. Tucatinib-related toxic reactions that were grade 3 and above included thrombocytopenia (7 patients; 14%) and hepatic transaminitis (6 patients; 12%).

Conclusions and Relevance

In this study, tucatinib in combination with T-DM1 appeared to have acceptable toxicity and to show preliminary antitumor activity among heavily pretreated patients with ERBB2/HER2-positive metastatic breast cancer with and without brain metastases.

Trial Registration

ClinicalTrials.gov Identifier: NCT01983501.

The IAEA Human Health Campus: Online Educational Resource for Health Care Professionals in Radiation Medicine

Background: Cognizant of the educational needs of the member states, and taking advantage of the current technological advances in this digital age, the International Atomic Energy Agency (IAEA) officially launched in 2010 the Human Health Campus (HHC; http://humanhealth.iaea.org ), which is an online educational resource initiative geared toward enhancing professional knowledge of health professionals in radiation medicine. Aim: Determine how and by whom the IAEA HHC is being visited and used since its inception in October 2010. Methods: Using the information provided by Google Analytics, determine the overall key performance indicators (KPIs) such as total sessions, total users, total page views, session duration, including daily number of visits to the HHC, county of origin, evaluation of the most popular sections and source of the traffic. Results: Since its launch on October 6th, 2010, KPIs are as follows: total sessions 374,279, total users 243,195, total page views 1,393,310, pages/session 3.72, average session duration 00:03:08. % of new sessions 64.92%. The HHC has witnessed continual growth year on year (YoY) in total sessions (visits) since its inception in October 2010, and total users. For 2016 (the highest performing year so far) there were 201 visits/day, 40% increase in traffic YoY and 20% user growth. Traffic to the Webinar content has seen sustained growth in the number of YoY since being introduced to the HHC in 2013. 2016 saw the largest increase of over +600%. E-Learning modules have also seen growth in the traffic YoY since being introduced to the HHC in 2011. The year 2015 saw a large increase in total traffic with over +95%. E-Learning traffic accounts for almost 25% of all traffic to the Nuclear Medicine section. Visits by mobile devices have increased YoY exponentially since the launch of the HHC, with the mobile traffic growing strong through 2015-2016 with an increase of 5482 sessions, or an 81% uplift YoY. For 2017, it represented 18% of the total traffic (from 3% in 2012). There is a clear prevalence of desktop users (85.5%), as the preferred method of browsing the HHC. A total of 210 countries and overseas territories have visited the HHC. The United States is the largest contributor of traffic from a global perspective with 16.31% of total traffic, almost double the next largest which is the UK with 9.10%. India with 5.45% and Australia with 3.27% of total traffic, respectively, round out the top 4. Not surprisingly, more than 60% of users are from English-speaking countries. Spanish is the second most popular language of users with just over 6% of total traffic. Conclusion: The HHC is an IAEA open access Web based educational resource for professionals in the field of radiation medicine being visited by as many as 210 countries. The upward trend in its use suggests that the IAEA HHC will continue to be an important player in providing educational resources for professionals worldwide.

Dynamics of virus-specific T cell immunity in pediatric liver transplant recipients

Immunosuppression following solid organ transplantation (SOT) has a deleterious effect on cellular immunity leading to frequent and prolonged viral infections. To better understand the relationship between posttransplant immunosuppression and circulating virus-specific T cells, we prospectively monitored the frequency and function of T cells directed to a range of latent (CMV, EBV, HHV6, BK) and lytic (AdV) viruses in 16 children undergoing liver transplantation for up to 1 year posttransplant. Following transplant, there was an immediate decline in circulating virus-specific T cells, which recovered posttransplant, coincident with the introduction and subsequent routine tapering of immunosuppression. Furthermore, 12 of 14 infections/reactivations that occurred posttransplant were successfully controlled with immunosuppression reduction (and/or antiviral use) and in all cases we detected a temporal increase in the circulating frequency of virus-specific T cells directed against the infecting virus, which was absent in 2 cases where infections remained uncontrolled by the end of follow-up. Our study illustrates the dynamic changes in virus-specific T cells that occur in children following liver transplantation, driven both by active viral replication and modulation of immunosuppression.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Variation in heterostylous breeding systems in neighbouring populations of Oxalis alpina (Oxalidaceae)

The heterostylous reproductive system of Oxalis alpina in the Galiuro Mts. of Arizona was investigated using field surveys, controlled crosses in the greenhouse and measurements of reproductive morphs. Although populations in the Pinaleño Mts. to the immediate east and in the Santa Catalina Mts. to the immediate west have derived distylous reproductive systems, tristyly, the ancestral reproductive system in O. alpina, has been retained in the Galiuro Mts.

POPULATION

Tristylous incompatibility relationships in the Galiuro population are modified from the ancestral condition, with significant loss of incompatibility differentiation between stamen whorls of both short- and long-styled morphs. Morphological adjustments of anther positions in the Galiuro population of O. alpina match those expected in light of incompatibility modification, with divergence of the mid-level anthers away from the position of the mid stigmas of the mid-styled morph. The occurrence of tristyly in an area of Arizona where distyly is found in adjacent mountain ranges is particularly remarkable, and indicates both the isolation of populations restricted to the upper elevations of these mountain ranges and variation in the tempo of evolution over short geographic distances.

Peginterferon Lambda-1a Is Associated with a Low Incidence of Autoimmune Thyroid Disease in Chronic Hepatitis C

Peginterferon alfa (alfa) increases the risk of autoimmune disease. Peginterferon lambda-1a (Lambda) acts through a receptor with a more liver-specific distribution compared to the alfa receptor. In a phase-2b study, 525 treatment-naive patients with chronic hepatitis C virus (HCV) infection received ribavirin and Lambda interferon (120, 180, or 240 μg) or alfa interferon (180 μg) for 24 (genotypes 2 and 3) or 48 (genotypes 1 and 4) weeks. Retrospective analysis found that adverse events of MedDRA-coded thyroid dysfunction and abnormal levels of thyroid-stimulating hormone (TSH) were significantly more frequent with alfa versus Lambda (12% versus 2.6% and 15.2% versus 3.4%, respectively, both P<0.0001). Most Lambda recipients with abnormal TSH had levels below the lower limit of normal; the frequency of low and high TSH was similar in alfa recipients with abnormal TSH. Blinded review by an endocrinologist found that new-onset primary hypothyroidism or painless thyroiditis was less frequent with Lambda versus alfa (0.5% and 1.8% versus 5.3% and 7.5%, respectively, P<0.0001). Most TSH elevations reflected new-onset hypothyroidism requiring treatment, while most markedly suppressed TSH values reflected probable painless thyroiditis and resolved without sequelae. In conclusion, HCV-infected patients treated with Lambda/ribavirin experienced fewer adverse events of thyroid dysfunction compared with patients treated with alfa/ribavirin.

Fishpathogens.eu/noda: a free and handy online platform for Betanodavirus targeted research and data sharing

Viral nervous necrosis (VNN) is a severe neuropathological disease affecting a broad variety of finfish species worldwide. The causative agents of VNN are small viruses with a bi-segmented RNA genome known as betanodaviruses. At least four species with distinct but yet insufficiently characterized epidemiological features are recognized. The spread of VNN to an increasing number of host species, its wide geographic extent and its economical and ecological impacts justify the importance of collating as much molecular data as possible for tracing the origin of viral isolates and highlight the need for a freely accessible tool for epidemiological and molecular data sharing and consultation. For this purpose, we established a web-based specific database using the www.fishpathogens.eu platform, with the aim of collecting molecular and epidemiological information on VNN viruses, with relevance to their control, management and research studies.

A randomized phase 2b study of peginterferon lambda-1a for the treatment of chronic HCV infection

BACKGROUND & AIMS

Peginterferon lambda-1a (Lambda) is a type-III interferon with similar antiviral activity to alfa interferons but with a diminished extrahepatic receptor distribution, reducing the risk for extrahepatic adverse events.

METHODS

This was a randomized, blinded, actively-controlled, multicentre phase 2b dose-ranging study in patients chronically infected with HCV genotypes 1-4. Treatment-naive patients received Lambda (120/180/240 μg) or peginterferon alfa-2a (alfa; 180 μg) once-weekly with ribavirin for 24 (genotypes [GT] 2,3) or 48 (GT1,4) weeks.

RESULTS

Rates of undetectable HCV-RNA at week 12 (complete early virologic response [cEVR]; primary end point) were significantly higher in GT1,4 patients receiving Lambda vs. alfa (170/304, 56% vs. 38/103, 37%); with similar cEVR rates for GT2,3 (80/88, 91% vs. 26/30, 87%). Rates of undetectable HCV-RNA at week 4 were significantly higher on 180 μg (15/102, 15% GT1,4; 22/29, 76% GT2,3) and 240 μg (17/104, 16% GT1,4; 20/30, 67% GT2,3) Lambda than alfa (6/103, 6% GT1,4; 9/30, 30% GT2,3). Sustained virologic responses (post-treatment week 24) were comparable between Lambda and alfa for GT1,4 (37-46% Lambda; 37% alfa) and GT2,3 (60-76% Lambda; 53% alfa). Aminotransferase and/or bilirubin elevations were the primary dose-limiting abnormalities for Lambda; a sponsor-mandated 240 to 180 μg dose reduction was therefore implemented. Serious adverse events were comparable (3-13% Lambda; 3-7% alfa). Grade 3-4 haemoglobin, neutrophil, and platelet reductions were lower on Lambda than alfa. Among alfa patients, 28/133 (21%) had peginterferon and 31/133 (23%) had ribavirin dose reductions for haematologic abnormalities vs. 0/392 and 8/392 (2%) on Lambda. Lambda demonstrated fewer musculoskeletal (16-28% vs. 47-63%) and influenza-like events (8-23% vs. 40-46%) than alfa.

CONCLUSION

Lambda was associated with improved or similar rates of virologic response with fewer extrahepatic adverse events than alfa in chronic HCV infection.

Evaluation of Flexural, Diametral Tensile, and Shear Bond Strength of Composite Repairs

Objective

Repairing composite restorations may be a more conservative treatment than replacing the entire restoration. The objective of this in vitro study was to determine the best repair method by measuring flexural, diametral tensile, and shear bond strength of repaired composites in which the surfaces were treated with chemical primers (Add & Bond or Silane Bond Enhancer), a bonding agent (Optibond Solo Plus [OBSP]), or mechanical retention with a bonding agent.

Methods

Filtek Supreme Ultra shade B1B was placed in special molds to fabricate specimens that served to test the flexural, diametral tensile, or shear strength of the inherent resin substrate. The same molds were modified to make specimens for testing repair strength of the resin. Repairs were made immediately or after aging in deionized water at 37°C for seven days. All repair sites were finished with coarse Sof-Lex discs to simulate finishing new restorations or partially removing aged restorations. Repair surfaces were treated with one of the following: 1) phosphoric-acid etching and OBSP; 2) Add & Bond; 3) phosphoric-acid etching, Silane Bond Enhancer, and OBSP; or 4) quarter round bur, phosphoric-acid etching, and OBSP. Specimens were placed back in the original molds to fabricate specimens for diametral tensile or flexural testing or in an Ultradent jig to make specimens for shear bond testing. Composite resin in shade B5B was polymerized against the treated surfaces to make repairs. Two negative control groups for the three testing methods consisted of specimens in which repairs were made immediately or after aging without any surface treatments. Controls and experimental repairs were aged (water 37°C, 24 hours) before flexural, diametral tensile, or shear testing in an Instron Universal testing machine at a crosshead speed of 0.5 mm/min.

Results

Experimental flexural repair strengths ranged from 26.4% to 88.6% of the inherent substrate strength. Diametral tensile repair strengths ranged from 40% to 80% of the inherent substrate strength, and shear bond strength repairs ranged from 56% to 102%. Geometric means were statistically analyzed with two-way analysis of variance on their log-transformed values. Significant differences were determined using Tukey honestly significant difference (p&lt;0.05).

Conclusions

Depending on the mechanical property being tested, surface treatments produced different results. OBSP produced more consistent results than chemical primers.

Pegylated interferons Lambda-1a and alfa-2a display different gene induction and cytokine and chemokine release profiles in whole blood, human hepatocytes and peripheral blood mononuclear cells

Pegylated interferon-lambda-1a (Lambda), a type III interferon (IFN) in clinical development for the treatment of chronic HCV infection, has shown comparable efficacy and an improved safety profile to a regimen based on pegylated IFN alfa-2a (alfa). To establish a mechanistic context for this improved profile, we investigated the ex vivo effects of Lambda and alfa on cytokine and chemokine release, and on expression of IFN-stimulated genes (ISGs) in primary human hepatocytes and peripheral blood mononuclear cells (PBMCs) from healthy subjects. Our findings were further compared with changes observed in blood analysed from HCV-infected patients treated with Lambda or alfa in clinical studies. mRNA transcript and protein expression of the IFN-λ-limiting receptor subunit was lower compared with IFN-α receptor subunits in all cell types. Upon stimulation, alfa and Lambda induced ISG expression in hepatocytes and PBMCs, although in PBMCs Lambda-induced ISG expression was modest. Furthermore, alfa and Lambda induced release of cytokines and chemokines from hepatocytes and PBMCs, although differences in their kinetics of induction were observed. In HCV-infected patients, alfa treatment induced ISG expression in whole blood after single and repeat dosing. Lambda treatment induced modest ISG expression after single dosing and showed no induction after repeat dosing. Alfa and Lambda treatment increased IP-10, iTAC, IL-6, MCP-1 and MIP-1β levels in serum, with alfa inducing higher levels of all mediators compared with Lambda. Overall, ex vivo and in vivo induction profiles reported in this analysis strongly correlate with clinical observations of fewer related adverse events for Lambda vs those typically associated with alfa.

Organo-selenium-containing dental sealant inhibits bacterial biofilm

Oral bacteria, including Streptococcus mutans and Streptococcus salivarius, contribute to tooth decay and plaque formation; therefore, it is essential to develop strategies to prevent dental caries and plaque formation. We recently showed that organo-selenium compounds covalently attached to different biomaterials inhibited bacterial biofilms. Our current study investigates the efficacy of an organo-selenium dental sealant (SeLECT-Defense(TM) sealant) in inhibiting S. mutans and S. salivarius biofilm formation in vitro. The organo-selenium was synthesized and covalently attached to dental sealant material via standard polymer chemistry. By colony-forming unit (CFU) assay and confocal microscopy, SeLECT-Defense(TM) sealant was found to completely inhibit the development of S. mutans and S. salivarius biofilms. To assess the durability of the anti-biofilm effect, we soaked the SeLECT-Defense(TM) sealant in PBS for 2 mos at 37°C and found that the biofilm-inhibitory effect was not diminished after soaking. To determine if organo-selenium inhibits bacterial growth under the sealant, we placed SeLECT-Defense sealant over a lawn of S. mutans. In contrast to a control sealant, SeLECT-Defense(TM) sealant completely inhibited the growth of S. mutans. These results suggest that the inhibitory effect of SeLECT-Defense(TM) sealant against S. mutans and S. salivarius biofilms is very effective and durable.

Observation of a relaxed plasma state in a quasi-infinite cylinder

A helical relaxed plasma state is observed in a long cylindrical volume. The cylinder is long enough so that the predicted minimum energy state is a close approximation to the infinite cylinder solution. The plasma is injected at v ≥ 50 km/s by a coaxial magnetized plasma gun located at one end of the cylindrical volume. The relaxed state is rapidly attained in 1-2 axial Alfvén times after initiation of the plasma. Magnetic data are favorably compared with an analytical model. Magnetic data exhibit broadband fluctuations of the measured axial modes during the formation period. The broadband activity rapidly decays as the energy condenses into the lowest energy mode, which is in agreement with the minimum energy eigenstate of [Symbol: see text] × B = λB.

Linoleic acid improves the robustness of cells in agitated cultures

The murine hybridoma (CC9C10) was subjected to high shear rates in a spinner flask to determine the effect of various culture additives on cell survival. At 500 rpm, the half-life of the viable cell concentration in a low protein serum-free medium was 50 min. Both bovine serum albumin and Pluronic F-68 had a significant effect in protecting cells under these conditions. The effects of the two supplements were additive, so that in the presence of both supplements there was minimal cell damage at 500 rpm. The survival rate of cells grown in media supplemented with linoleic acid improved significantly under high stirring rates. Cells grown for one passage in 50 muM linoleic acid and stirred at 500 rpm had a significantly higher survival rate than control cells. For cells grown over 5 passages in 25 muM linoleic acid, the survival rate at 470 rpm was x3 greater than that determined for control cells. This difference gradually decreased at higher stirring rates up to 610 rpm when the half-life of the viable cell population was reduced to approximately 10 min. Supplementation of cultures with linoleic acid has previously been shown to result in incorporation into all three cellular lipid fractions - polar, non-polar and free fatty acid (Butler et al., 1997). Our explanation for the increased survivability of the cells at high agitation rates in the presence of linoleic acid is that the structural lipid components of the cell including the outer membrane attained a higher unsaturated/saturated ratio which was more robust than that of control cells.

Calibrated cylindrical Mach probe in a plasma wind tunnel

A simple cylindrical Mach probe is described along with an independent calibration procedure in a magnetized plasma wind tunnel. A particle orbit calculation corroborates our model. The probe operates in the weakly magnetized regime in which probe dimension and ion orbit are of the same scale. Analytical and simulation models are favorably compared with experimental calibration.

Phase 1b study of pegylated interferon lambda 1 with or without ribavirin in patients with chronic genotype 1 hepatitis C virus infection

Interferon lambda 1 (IFN-lambda1) is a type III IFN that produces intracellular responses similar to those of IFN-alpha but in fewer cell types because of differences in the receptor distribution pattern, and this could potentially result in an improved safety profile. This was an open-label three-part study of patients with chronic hepatitis C virus (HCV) genotype 1 infection. Part 1 evaluated single-agent pegylated interferon lambda (PEG-IFN-lambda) at 1.5 or 3.0 microg/kg administered every 2 weeks or weekly for 4 weeks in patients who had relapsed after previous IFN-alpha-based treatment. Part 2 evaluated weekly doses of PEG-IFN-lambda ranging from 0.5 to 2.25 microg/kg in combination with ribavirin (RBV) for 4 weeks in treatment-relapse patients. Part 3 evaluated weekly PEG-IFN-lambda at 1.5 microg/kg in combination with RBV for 4 weeks in treatment-naive patients. Fifty-six patients were enrolled: 24 patients in part 1, 25 patients in part 2, and 7 patients in part 3. Antiviral activity was observed at all PEG-IFN-lambda dose levels (from 0.5 to 3.0 microg/kg). Two of seven treatment-naive patients (29%) achieved rapid virological response. Treatment was well tolerated with minimal flu-like symptoms and no significant hematologic changes other than RBV-associated decreases in hemoglobin. The most common adverse events were fatigue (29%), nausea (12%), and myalgia (11%). Six patients experienced increases in aminotransferases that met protocol-defined criteria for dose-limiting toxicity (DLT) or temporarily holding therapy with PEG-IFN-lambda. Most DLT occurred in patients with high PEG-IFN-lambda exposure.

CONCLUSION

Weekly PEG-IFN-lambda with or without daily RBV for 4 weeks is well tolerated with minimal adverse events and hematologic effects and is associated with clear antiviral activity across a broad range of doses in patients with chronic HCV.

An isolate and sequence database of infectious haematopoietic necrosis virus (IHNV)

In the field of fish diseases, the amount of relevant information available is enormous. Internet-based databases are an excellent tool for keeping track of the available knowledge in the field. Fishpathogens.eu was launched in June 2009 with the aim of collecting, storing and sorting data on fish pathogens. The first pathogen to be included was the rhabdovirus, viral haemorrhagic septicaemia virus (VHSV). Here, we present an extension of the database to also include infectious haematopoietic necrosis virus (IHNV). The database is developed, maintained and managed by the European Community Reference Laboratory for Fish Diseases and collaborators. It is available at http://www.fishpathogens.eu/ihnv.

Observation of a helical self-organized state in a compact toroidal plasma

A nonaxisymmetric stable magnetohydrodynamic (MHD) equilibrium within a prolate cylindrical conducting boundary has been produced experimentally. It has m=1 azimuthal symmetry, helical distortion, and flat lambda profile, all in agreement with the computed magnetically relaxed minimum magnetic energy Taylor state. Despite varied initial conditions determined by two helicity injectors on the device, this same equilibrium consistently emerges as the final state. These results therefore describe a new example of self-organization in an MHD plasma.

FishPathogens.eu/vhsv: a user-friendly viral haemorrhagic septicaemia virus isolate and sequence database

A database has been created, http://www.FishPathogens.eu, with the aim of providing a single repository for collating important information on significant pathogens of aquaculture, relevant to their control and management. This database will be developed, maintained and managed as part of the European Community Reference Laboratory for Fish Diseases function. This concept has been initially developed for viral haemorrhagic septicaemia virus and will be extended in future to include information on other significant aquaculture pathogens. Information included for each isolate comprises sequence, geographical origin, host origin and useful key literature. Various search mechanisms make it easy to find specific groups of isolates. Search results can be presented in several different ways including table-based, map-based and graph-based outputs. When retrieving sequences, the user is given freedom to obtain data from any selected part of the genome of interest. The output of the sequence search can be readily retrieved as a FASTA file ready to be imported into a sequence alignment tool of choice, facilitating further molecular epidemiological study.

ERCC-1 (E) expression and its effect on survival in patients (pts) receiving concurrent cisplatin (C) and radiation (R) for locally advanced head and neck cancer (HNC)

e17033

Background: E is a DNA repair gene involved in the nucleotide excision repair pathway. Overexpression of E has been associated with resistance to C in patients with ovarian, gastric, and lung cancer. We retrospectively analyzed tissue from HNC pts who received concurrent C and R to determine if E expression was a significant independent predictor of survival. Methods: Eligible HNC pts had squamous cell histology and received definitive concurrent C and R at the Dallas VAMC. Tissue was immunostained for E using ERCC-1,clone 8F, 1:100 dilution (Abcam, Cat#ab2356, Cambridge, MA) diluted in ChemMate buffer (Ventana Medical Systems, Tucson, AZ) on a BenchMarkXT automated immunostainer using the UltraVIEW system with horseradish peroxidase and diaminobenzidine (DAB) chromogen (Ventana Medical Systems, Tucson, AZ) per the standard protocol of the UT Southwestern Pathology Immunohistochemistry Laboratory. E scoring was determined by 2 pathologists blinded to clinical outcomes. Scoring was as follows: 0 = 0% of tumor nuclei were positive, 1+ = less than 50%, 2+ = 50–75% and 3+ = 75–100%. Results: 73 consecutively treated patients were analyzed. Median age 59 (range 41 - 80); 99% male; 7% stage II, 19% stage III, 73% stage IV; primary site - 4% oral cavity, 56% oropharynx, 14% hypopharynx, 23% larynx, 3% nasopharynx; Tumor grade - 60% moderately differentiated, 4% well differentiated, 15% poorly differentiated, 21% not specified; Performance status 0–25%, 1–45%, 2–8%, unknown-22%; E scoring was 0 in 0%, 1+ (14%), 2+ (42%), 3+ (44%). In univariate analysis, E staining 3+ was not predictive of survival with a hazard ratio (HR) of .796 (95% CI .44–1.43; p = 0.44). In multivariate analysis, the only significant predictor was hypopharynx with a HR of 3.18 (95% CI 1.02–9.88; p = 0.046). HR for age > 60 was 2.16 (95% CI .96–4.86; p = 0.06). E staining 3+ was not predictive of survival with a HR of .69 (95% CI .3–1.56; p = 0.37). Median survival (MS) for the whole group was 2.8 years (y); 5y survival - 41%. MS for the E 3+ pts - 2.1y; 5y survival 38%. MS for the E < 3+ pts - 2.9y; 5y survival 44% (p = not significant). Conclusions: In our retrospective review of HNC patients receiving concurrent C and R, E staining was not a significant predictor of survival.

No significant financial relationships to disclose.

Absence of telomere shortening and oxidative DNA damage in the young adult offspring of women with pre-gestational type 1 diabetes

AIMS/HYPOTHESIS

The offspring of mothers with pre-gestational type 1 diabetes (PGDM) may be at increased risk of glucose intolerance and cardiovascular disease in childhood. The underlying causes of these observations, and whether they persist into adulthood, are unknown. The aim of the present study was to test the hypothesis that fetal chromosomal telomere oxidative DNA damage resulting from maternal PGDM programmes the offspring towards a senescent phenotype that is detectable in young adulthood.

METHODS

We studied 21 young adult offspring (age 16-23 years) with a maternal history of PGDM and 23 age- and weight-matched controls with no maternal history of diabetes. All participants underwent anthropometric assessments, a standard 75 g OGTT, measurement of peripheral blood mononuclear cell and skin fibroblast telomere length, fibroblast senescence, cell DNA damage (by determination of 8-oxoguanine levels using flow cytometry), plasma lipoprotein profiles (determined by nuclear magnetic resonance) and plasma levels of soluble adhesion molecules and inflammatory markers.

RESULTS

The groups did not differ significantly with respect to anthropometric measures, glucose tolerance, fasting and 2 h plasma insulin levels during OGTT, estimated peripheral insulin resistance, peripheral blood mononuclear cell or fibroblast telomere length, DNA damage or senescence in vitro, plasma NMR lipoprotein profiles or levels of high-sensitivity C-reactive protein. Plasma concentrations of soluble intercellular adhesion molecule 1 (sICAM-1; p < 0.05) and IL-6 (p = 0.08) were higher in the PGDM offspring.

CONCLUSIONS/INTERPRETATION

Young adult offspring of mothers with PGDM do not differ in terms of glucose tolerance, DNA damage or telomere length from controls of the same weight and BMI. This does not preclude such abnormalities at an earlier age, but there is no evidence of telomere damage as a pre-programming mechanism in the young adults enrolled in this study.

Enhanced energy confinement and performance in a low-recycling tokamak

Extensive lithium wall coatings and liquid lithium plasma-limiting surfaces reduce recycling, with dramatic improvements in Ohmic plasma discharges in the Current Drive Experiment-Upgrade. Global energy confinement times increase by up to 6 times. These results exceed confinement scalings such as ITER98P(y,1) by 2-3 times, and represent the largest increase in energy confinement ever observed for an Ohmic tokamak plasma. Measurements of Dalpha emission indicate that global recycling coefficients decrease to approximately 0.3, the lowest documented for a magnetically confined hydrogen plasma.

Isolation, culture, and characterisation of human macular inner choroidal microvascular endothelial cells

AIM

To develop a method for the reliable isolation of adult human macular inner choroidal endothelial cells (ICECs) and to subsequently characterise them for their expression of a range of endothelial cell associated surface markers.

METHOD

Human ICECs were isolated after manual dissection of maculas from fresh human posterior segments. Following enzyme digestion to form a single cell suspension, the ICECs were isolated using anti-CD31 coated Dynabeads. The isolated cells were grown in culture and examined for typical endothelial cell morphology, surface expression of vWf, CD 31, CD 105, VEGF receptors 1 and 2, and expression of E-selectin after stimulation with TNF-alpha. The cells were also examined for their ability to form fenestrations and capillary-like tubes in Matrigel.

RESULTS

The method enabled the rapid isolation of viable cells that demonstrated typical endothelial cobblestone morphology in culture. The cells stained positive for CD31, vWf, CD105, VEGF receptors 1 and 2, and E-selectin (after stimulation with TNF-alpha). The cells stained negative for alpha smooth muscle actin and fibroblast surface protein. The cells also developed fenestrations when cultured on fibronectin coated plates and formed capillary-like tubes structures when cultured on Matrigel.

CONCLUSIONS

This technique isolates cells from the human macular inner choroid that display features consistent with vascular endothelial cells. These cells could subsequently be used to further the understanding of the pathophysiological mechanisms of diseases of the inner choroid, such as choroidal neovascularisation.