ARTIA-Cervix: A Prospective Clinical Trial to Assess Patient Reported Intestinal Toxicity with Adaptive External Beam Radiation Therapy in the Treatment of Cervical Cancer

PURPOSE/OBJECTIVE(S)

Chemoradiation (CRT) remains the standard of care for locally advanced cervical cancer. As recent large phase III trials (OUTBACK, CALLA) reported no difference in primary survival outcomes when novel agents were added to CRT, technological advancements continue to be a focus for improving outcomes. Daily imaging has enabled margin reduction on the cervix, uterus and lymph nodes, which can lower radiation dose to bowel and potentially reduce RT-related symptoms. Daily adaptive RT (ART) combines daily imaging with online dosimetry replanning, allowing for decreased margins on the target. A pre-planning study showed bowel V40Gy and V45Gy reductions of 252 cc to140 cc and 167 cc to 43 cc, respectively. ARTIA-Cervix is a single-arm, prospective, multi-institutional, international clinical trial investigating the potential of ART to decrease patient-reported acute gastrointestinal (GI) toxicity.

MATERIALS/METHODS

Planned enrollment is 125 subjects with up to 8 sites participating. Eligibility criteria include locally advanced node-negative cervical cancer FIGO stages IB2-3B. Treatment will consist of cisplatin-based CRT with daily ART, followed by image-guided brachytherapy. Subjects will receive 25 fractions ART at 1.8 Gy per day for a total of 45 Gy. The primary study objective is reduction of patient-reported GI toxicity as measured by PRO-CTCAE score ≥3 at the conclusion of ART. Secondary objectives include patient-reported GU toxicity and sexual quality of life, the development of radiation dosimetry models predicting toxicity, physician-reported toxicities, 2-year disease free survival, and adaptive workflow metrics. Powering of the study and sample size calculation are based on the hypothesis that ART will decrease patient-reported acute GI toxicity from historical rates of 33% to 20% (13% effect size).

RESULTS

This study opened to enrollment on April 28th, 2022. The total study duration will be approximately 5 years.

CONCLUSION

ARTIA-Cervix is an international, prospective clinical trial designed to evaluate reduction of treatment-related GI toxicity through daily online ART. The results of this clinical study will add to the growing body of evidence supporting clinical decisions about utilization of ART technologies.

Clinical Impact of Contouring Variability for Prostate Cancer Tumor Boost

PURPOSE/OBJECTIVE(S)

In the FLAME randomized phase III trial, adding a focal radiotherapy (RT) boost to tumors visible on MRI improved prostate cancer disease-free survival, local control, and regional/distant metastasis-free survival without increasing toxicity. In a prospective study (ReIGNITE RT Boost), we found substantial variability in radiation oncologists' attempts to contour prostate cancer tumors on MRI. Participants' accuracy and reliability improved when they used a quantitative MRI biomarker for cancer called the restriction spectrum imaging restriction score (RSIrs). Here, we measure the impact of radiation oncologists' tumor contour attempts on RT plans and predicted probability of biochemical failure.

MATERIALS/METHODS

A total of 44 radiation oncologists (participants) from multiple institutions contoured prostate tumors on 30 patient cases, some with only conventional MRI and some with conventional MRI plus RSIrs maps. We developed a knowledge-based planning automated algorithm to generate RT plans with focal tumor boost per the FLAME trial protocol: 77 Gy in 35 fractions to prostate and integrated boost up to 95 Gy to the focal target, provided no normal tissue constraints were violated. We applied this algorithm to each participant's tumor contour and compared dosimetric parameters to those achieved when using the expert-defined tumor (consensus of two radiologists and a radiation oncologist). The primary metric was dose covering 98% of the expert-defined tumor (D98%), which was associated with probability of biochemical failure in a model published with the FLAME trial.

RESULTS

In this preliminary analysis, 42 target volumes were analyzed from 20 participants and two patient cases: case 1 was contoured with conventional MRI alone and case 2 with RSIrs. All plans had adequate coverage of the prostate and met all key normal tissue constraints. For case 1 (without RSIrs), the expert's D98% was 87.1 Gy. By comparison, median D98% for participants was 82.2 Gy (IQR 77.8 - 84.6 Gy). Per the FLAME trial model, the predicted probability of biochemical failure at 7 years is 6% for the expert, but participants' plans yielded a median failure probability of 11% (IQR 18 - 9%). For case 2 (with RSIrs), the expert's D98% was 82.8 Gy, while median D98% for participants was 80.6 Gy (IQR 80.0 - 81.0 Gy). Predicted probability of biochemical failure is 12% for the expert-defined target and median 13% (IQR 14 - 13%) for participants.

CONCLUSION

Variability in radiation oncologists' prostate tumor contours can lead to clinically meaningful changes to focal RT boost plans. The probability of biochemical failure for one patient case increased from 6% to a median of 11% when using conventional MRI alone. Use of RSIrs may mitigate this problem by increasing the accuracy and reliability of radiation oncologists' tumor contours.

Using Scorecards to Tune Ethos Directive Templates: An ARTIA Cervix Dosimetric Planning Study

PURPOSE/OBJECTIVE(S)

The Adaptive Radiation Therapy Individualized Approach (ARTIA) Cervix clinical trial uses predefined clinical directive templates (CDT) combined with RapidPlan DVH estimations (DVHe) to guide plan optimization in the Ethos treatment planning system. The dosimetric scorecard tool (DST) quantifies improvements in plan quality. This is the first study to utilize the DST to tune an Ethos CDT to improve resulting plan quality.

MATERIALS/METHODS

Iterative replanning was used to modify the draft CDT (CDT-1) in Ethos to generate a new CDT (CDT-2) that maximized the clinical consensus scorecard's total score compared toCDT-1. CDT-2 was established, and resulting plans were compared with and without a DVHe. Additional fixed field IMRT beam geometries were compared between CDT-1 and CDT-2, both with DVHe. After obtaining favorable results when comparing CDT-1 verses CDT-2 for two test cases, 10 additional cases were retrospectively identified and tested.

RESULTS

For the initial test cases, CDT-2 decreased OAR doses without compromising PTV coverage (No DVHe). While both plans met the protocol target guidelines and OAR constraints, the scorecard was able to quantify the improvement with CDT-2 on a test case with a score of 166.1 (78.7%) vs CDT-1, 163.87 (77.6%). When CDT-2 was combined with the DVHe, it still marginally outperformed CDT-1: 168.73 (76%) versus 166.13 (74.8%). Plan quality was further improved by increasing the total number of fields to 19. Combining CDT-2 and DVHe with a 19-field geometry resulted in the greatest benefit at 184.6 (83.2%). This scored higher than the ARTIA-Cervix defined delivery technique of CDT-1 and DVHe, with a 9-field geometry 166.1 (74.8%). The study was expanded to a separate analysis on 10 new cases. The 19-field approach was superior for all 10 cases and CDT-2 achieved a higher score in 7/10 cases. When comparing 9 versus 19 fields, the total optimization and calculation time increased by an average of 1.9 minutes while the beam delivery time increased by an average of 2.8 minutes (+/- 0.1). The average MU/field was 174.3 (total 1568.3) and 129.9 (total 2468) for 9 and 19 fields, respectively. Two test plans were re-optimized and calculated with Ethos 1.1 maintenance release (MR) 1 with both 9 and 19 fields. For case 1, MR 1 resulted in an 8.4% and 6.9% decrease in MU and scored -0.6% and +0.5% for 9 and 19 fields, respectively. For case 2, MR 1 resulted in a 0.8% and 3.1% decrease in MU and scored -3.4% and -0.3% for 9 and 19 fields, respectively.

CONCLUSION

The scorecard allows for easy evaluation of the dosimetric impact of other planning parameters (beam arrangements and use of DVHe) to identify the best approach. Using a scorecard to finely-tune a CDT is expected to improve planning efficiency, decrease intra-institutional plan quality and variability, improve the average calculated plan quality and benefit CBCT-guided ART.

Identifying and Re-Planning Challenging Retrospective SRS Patients to Evaluate the Potential for a White Matter Tract Sparing Knowledge-Based Planning Model

PURPOSE/OBJECTIVE(S)

Diffusion tensor imaging (DTI) with automated tractography, along with auto-parcellation of volumetric MRI (vMRI), allows for reliable parcellation of critical white matter (WM) and hippocampal structures in the brain. Knowledge-based planning (KBP) may facilitate the optimization of new brain SRS plans that highly prioritize WM tracts and hippocampal sparing, allowing for cognitive preservation. However, building a high-performing model is challenging as the geometry of WM tracts and their proximity to planning target volumes (PTVs) can vary substantially. In this work we propose an iterative step for creating a KBP model where we used a preliminary model to identify challenging plans and worked on improving their dosimetry to refine the model predictions.

MATERIALS/METHODS

Tractography of eloquent deep WM was obtained from high resolution DTI, along with auto-segmentation of bilateral hippocampi from vMRI and an open-source software for processing and analyzing brain MRI images. These ROIs were imported to the treatment planning system as organs-at-risk (OARsDTI). A preliminary KBP model was built from an IRB-approved cohort of 30 consecutive patients (75 plans total) treated for brain metastasis with non-coplanar SRS with total dose from 20 to 30 Gy in one to five fractions using a LINAC. This preliminary model was used to identify the 7 plans with the highest doses to the OARsDTI. These plans were re-optimized with new objectives on the OARsDTI that were partially or totally overlapped with the isodose line representing 30% of the prescription dose (as a surrogate for proximity to the PTV). The OARsDTI that were overlapping with the PTV were excluded from this analysis. We evaluated the re-optimized plans (PlanNew) by comparing maximum and mean dose (Dmax and Dmean, respectively) of OARsDTI to the initial values from the preliminary plans (PlanPre). In order to verify that the PlanNew were not compromising other structures or treatment goals, we also evaluated conformity index (CI), PTV coverage and the dosimetry of OARs included in the PlanPre. Additionally, the PlanNew were normalized to our clinical standard used for the PlanPre (100% of prescription dose to 98% of the PTV).

RESULTS

In the 7 plans, there were 30 OARsDTI overlapping with the 30% isodose line. Refining the dosimetric objectives for the OARsDTI decreased the Dmean on average 31% when comparing PlanNew to Planpre (p<0.05, Wilcoxon rank-sum test). The CI of the PlanNew were not statistically different from the PlanPre. Although Dmax of PlanNew was 12% lower than Dmax of Planpre, the difference was not statistically different.

CONCLUSION

The addition of a plan refinement step was shown to improve dose to the OARsDTI in 7 challenging SRS plans. The generation of these plans are a necessary step to creating a refined KBP model capable of accounting for the high variability in WM tracts geometry and their proximity with PTV.

EPIDEEP: Using a Deep Learning Model to Predict In Vivo Electronic Portal Imaging Device (EPID) Transit Images

PURPOSE/OBJECTIVE(S)

To create a deep-learning model to predict in-vivo electronic portal imaging device (EPID) transit images for IMRT treatments. This model was created to predict in-vivo images to identify machine and patient-related errors that occur during beam delivery and are undetectable with current QA approaches. The deep-learning model can make image predictions much faster than Monte Carlo approaches, making image prediction feasible for application in online adaptive radiotherapy. Additionally, the model does not rely on any proprietary information and can be easily utilized by other clinics.

MATERIALS/METHODS

Our approach separates the primary and scatter components of in-vivo transit images. The attenuation of primary radiation reaching the EPID panel is modeled analytically, using attenuation measurements from phantoms of known thicknesses. The scatter component is estimated using a convolutional neural network (CNN). The CNN training uses information from the on-treatment cone-beam CTs (CBCTs), and a pretreatment EPID image with no patient in the beam. We acquired 193 IMRT fields/images from 118 patients previously treated on the Varian Halcyon. Treatment sites included the pelvis, abdomen, lungs, and extremities. CBCTs were collected immediately before treatment, to provide an accurate representation of the anatomy. A 3-channel input image was used, consisting of the pretreatment EPID image, a ray tracing projection through the CBCT to the EPID panel, and a projection to isocenter. Model training:validation:test set ratios were 133:20:40 images. The primary and scatter components are added together to give the predicted transit image. Prediction accuracy was assessed by comparing model-predicted and measured in-vivo EPID images with a 3%/3mm and 5%/3mm gamma pass rate.

RESULTS

The gamma pass rate for the patients in the training:validation:test was 91.5%:90.4%:92.1% for 3%/3mm and 96.7%:96.6%:97.0% for 5%/3mm. The model can make image predictions in 20 milliseconds. The poor passing rates of some images may be due to CBCT artifacts and patient motion that occurs between the time of CBCT and treatment.

CONCLUSION

This model can predict in-vivo EPID images with an average gamma pass rate greater than 90%. Image predictions from this model can be used to detect in-vivo treatment errors and changes in patient anatomy, providing an additional layer of patient-specific quality assurance. The speed of image predictions is 20 milliseconds, making use feasible for online adaptive treatments, which currently do not utilize patient-specific measurements of the delivered radiation. Upcoming studies will assess the model's ability in detecting clinically relevant errors and changes in patient anatomy that can adversely affect treatment. Future goals include acquiring more data to further improve the model and extending the model to make predictions for VMAT treatments.

Denitrifying pathways dominate nitrous oxide emissions from managed grassland during drought and rewetting

Nitrous oxide is a powerful greenhouse gas whose atmospheric growth rate has accelerated over the past decade. Most anthropogenic N2O emissions result from soil N fertilization, which is converted to N2O via oxic nitrification and anoxic denitrification pathways. Drought-affected soils are expected to be well oxygenated; however, using high-resolution isotopic measurements, we found that denitrifying pathways dominated N2O emissions during a severe drought applied to managed grassland. This was due to a reversible, drought-induced enrichment in nitrogen-bearing organic matter on soil microaggregates and suggested a strong role for chemo- or codenitrification. Throughout rewetting, denitrification dominated emissions, despite high variability in fluxes. Total N2O flux and denitrification contribution were significantly higher during rewetting than for control plots at the same soil moisture range. The observed feedbacks between precipitation changes induced by climate change and N2O emission pathways are sufficient to account for the accelerating N2O growth rate observed over the past decade.

Improving wheat as a source of iron and zinc for global nutrition

Wheat is the staple food crop in temperate countries and increasingly consumed in developing countries, displacing traditional foods. However, wheat products are typically low in bioavailable iron and zinc, contributing to deficiencies in these micronutrients in countries where wheat is consumed as a staple food. Two factors contribute to the low contents of bioavailable iron and zinc in wheat: the low concentrations of these minerals in white flour, which is most widely consumed, and the presence of phytates in mineral‐rich bran fractions. Although high zinc types of wheat have been developed by conventional plant breeding (biofortification), this approach has failed for iron. However, studies in wheat and other cereals have shown that transgenic (also known as genetically modified; GM) strategies can be used to increase the contents of iron and zinc in white flour, by converting the starchy endosperm tissue into a ‘sink’ for minerals. Although such strategies currently have low acceptability, greater understanding of the mechanisms which control the transport and deposition of iron and zinc in the developing grain should allow similar effects to be achieved by exploiting naturally induced genetic variation. When combined with conventional biofortification and innovative processing, this approach should provide increased mineral bioavailability in a range of wheat products, from white flour to wholemeal.

Genetic analysis of carcass traits in beef cattle using random regression models

Livestock mature at different rates depending, in part, on their genetic merit; therefore, the optimal age at slaughter for progeny of certain sires may differ. The objective of the present study was to examine sire-level genetic profiles for carcass weight, carcass conformation, and carcass fat in cattle of multiple beef and dairy breeds, including crossbreeds. Slaughter records from 126,214 heifers and 124,641 steers aged between 360 and 1,200 d and from 86,089 young bulls aged between 360 and 720 d were used in the analysis; animals were from 15,127 sires. Variance components for each trait across age at slaughter were generated using sire random regression models that included quadratic polynomials for fixed and random effects; heterogeneous residual variances were assumed across ages. Heritability estimates across genders ranged from 0.08 (±0.02) to 0.34 (±0.02) for carcass weight, from 0.24 (±0.02) to 0.42 (±0.01) for conformation, and from 0.16 (±0.03) to 0.40 (±0.02) for fat score. Genetic correlations within each trait across ages weakened as the interval between ages compared lengthened but were all >0.64, suggesting a similar genetic background for each trait across different ages. Eigenvalues and eigenfunctions of the additive genetic covariance matrix revealed genetic variability among animals in their growth profiles for carcass traits, although most of the genetic variability was associated with the height of the growth profile. At the same age, a positive genetic correlation (0.60 to 0.78; SE ranged from 0.01 to 0.04) existed between carcass weight and conformation, whereas negative genetic correlations existed between fatness and both conformation (-0.46 to 0.08; SE ranged from 0.02 to 0.09) and carcass weight (-0.48 to -0.16; SE ranged from 0.02 to 0.14) at the same age. The estimated genetic parameters in the present study indicate genetic variability in the growth trajectory in cattle, which can be exploited through breeding programs and used in decision support tools.

Effect of feed restriction and initial body weight on growth performance, body composition, and hormones in male pigs immunized against gonadotropin-releasing factor

Pigs immunized against gonadotropin-releasing factor (GnRF) have increased carcass fatness compared to entire males; however, the timing of this increase in fatness after the second immunization against GnRF has not been determined. An experiment was conducted to identify and compare the growth performance, body composition, and physiological changes in immunocastrated males (IC males) at different BW and feeding levels. A total of 64 pigs were used in a 2 × 2 × 2 factorial experiment with the treatments being 1) sex (entire males or IC males), 2) initial BW (45.9 kg [light] or 78.3 kg [heavy]), and 3) feeding regime (2.5 times maintenance [restricted] or ad libitum). The pigs were individually housed, and the diets were fed for 4 wk after the second immunization against GnRF until slaughter at either 68.4 kg BW (light) or 105.8 kg BW (heavy). Immunocastrated males on a restricted feed intake had a lower ADG compared to entire males from d 15 to 28 and d 0 to 28 ( 0.011 and 0.011, respectively). Fat deposition was not affected by sex from d 0 to 14, but from d 15 to 28 IC males deposited 45 g/d more fat than entire males ( = 0.025). Immunocastrated male pigs fed ad libitum deposited 87 g/d more fat from d 15 to 28 than entire males fed ad libitum ( = 0.036). However, there was no difference in fat deposition between IC males and entire males when feed intake was restricted from d 15 to 28. Plasma urea nitrogen levels were greater in IC males compared to entire males from d 7 after the second immunization against GnRF ( 0.05 for d 7, 10, 14, 21, and 28). Plasma concentrations of IGF-1 were lower for IC males compared to entire males on d 3, 7, 10, and 28 ( 0.05 for all days). The following conclusions were made: 1) when pigs are immunized at a light BW (50 kg) and/or are on a restricted feed intake, they have a reduced propensity to deposit fat; however, the restriction in feed intake adversely affects growth rate. 2) The majority of fat deposition for males immunized at heavy BW (80 kg) occurs from d 15 to 28 after the second immunization against GnRF.

Supra-nutritional vitamin E supplementation for 28 days before slaughter maximises muscle vitamin E concentration in finisher pigs

A 4 × 3 factorial experiment (n=8 pigs per treatment combination) was conducted with 96 female Landrace × Large White pigs to examine the required level of dietary vitamin E and optimum feeding duration before slaughter to maximise muscle vitamin E content in the Longissimus thoracis et lumborum (LTL) muscle. The respective factors were four dietary levels of vitamin E (supplemented as dl-α-tocopheryl acetate; 35, 300, 500, and 700 IU/kg) and three feeding durations (14, 28 and 42 days before slaughter). Vitamin E concentration in the LTL was maximised at 6 mg/kg, which was achieved by feeding a 700 IU vitamin E diet for 28 days before slaughter (P<0.001). There was no further increase in the vitamin E content of the LTL by feeding the high vitamin E diet more than 28 days before slaughter.

Patterns of chronic co-morbid medical conditions in older residents of U.S. nursing homes: differences between the sexes and across the agespan

OBJECTIVE

There are limited data on combinations of co-morbid conditions to guide efforts to improve therapeutic strategies in patients with multiple co-morbid conditions. To some extent, this may be due to limited data on combinations of co-morbid conditions in patient groups. Our goal was to determine the most common co-morbid medical conditions in older residents of U.S. nursing homes and identify sex differences in prevalences and changes across the agespan of nursing residents.

DESIGN

Cross sectional analysis of National Nursing Home Survey (NNHS)--a nationally representative sample with comprehensive medical data on nursing home residents.

SETTING

1174 Nursing homes.

PARTICIPANTS

Long term stay residents of U.S. Nursing Homes aged 65 years and older (11,734 :8745 women, 2989 men).

MEASUREMENTS

Determination of the prevalences of the most frequent two and three disease combinations identified using Clinical Classifications Software (CCS) for ICD-9-CM and a composite vascular disease diagnosis (atherosclerosis and/or coronary artery disease, and/or peripheral arterial disease, and/or cerebrovascular disease or stroke) from the most recent and only NNHS survey with comprehensive medical diagnosis information.

RESULTS

Frequent 2-disease combinations were: hypertension (HTN) + dementia (DEM) in 27%, HTN + any Vascular (Vasc) disease (26%), HTN + depression(DEP) 21%, HTN + arthritis(ARTH) 20%, DEM + Vasc (21%), DEM+Depression 19%, Arthritis + DEM 17%, DEP + Vasc (16%), ARTH + Vasc (15%), followed by HTN + GERD (14%) and ARTH + DEP (14%). Frequent 3-disease combinations: HTN +VASC+ DEP in 13%, HTN +DEM +DEP (11%), and HTN+Arthritis+DEM (10%). HTN was in 80% of the top 3-disease combinations, Vasc in 50%, HTN+VASC in 35%, DEM or DEP in 40%, ARTH in 25% and GERD in 20%. Combinations with anemia, arthritis, dementia, heart failure, osteroporosis, thyroid disease were higher in women, COPD combinations higher in men. As age increased, dementia, depression, arthritis, and anemia with hypertension were common co-morbid combinations, diabetes and heart failure were not.

CONCLUSIONS

Hypertension, vascular disease, dementia, arthritis, depression, and gastro-esophageal reflux disease were part of the most prevalent co-morbid conditions. Multimorbidity patterns can be identified in nursing home residents and vary with age and by sex.

Examinations of oxidation and sulfidation of grain boundaries in alloy 600 exposed to simulated pressurized water reactor primary water

High-resolution characterizations of intergranular attack in alloy 600 (Ni-17Cr-9Fe) exposed to 325°C simulated pressurized water reactor primary water have been conducted using a combination of scanning electron microscopy, NanoSIMS, analytical transmission electron microscopy, and atom probe tomography. The intergranular attack exhibited a two-stage microstructure that consisted of continuous corrosion/oxidation to a depth of ~200 nm from the surface followed by discrete Cr-rich sulfides to a further depth of ~500 nm. The continuous oxidation region contained primarily nanocrystalline MO-structure oxide particles and ended at Ni-rich, Cr-depleted grain boundaries with spaced CrS precipitates. Three-dimensional characterization of the sulfidized region using site-specific atom probe tomography revealed extraordinary grain boundary composition changes, including total depletion of Cr across a several nm wide dealloyed zone as a result of grain boundary migration.

Blend-feeding or feeding a single diet to pigs has no impact on growth performance or carcass quality

A completely randomised block experiment was conducted using 216 female pigs (Large White × Landrace, six pigs/pen and 12 replicate pens/treatment), at an average liveweight (LW) of 22.6 kg ± 0.56 (mean ± s.e.m.), to examine the effect of feeding strategies on performance during the grower–finisher phase. Pigs were blocked and randomly allocated to the following treatments on the basis of initial LW: (1) phase-feeding: diets changed when the average LW of pigs in the pen reached 20, 50 or 80 kg; (2) blend: diets changed weekly to meet the requirements of the average LW of pigs in the pen and; (3) single: the same diet fed throughout (formulated to meet the requirements of the pig at 60 kg LW). The experimental diets were fed from 22 to 102 kg LW. Between 68 and 98 days of age, pigs fed the single diet grew more slowly (P < 0.001) due to poorer feed conversion (P < 0.001) than did pigs fed the phase-feeding or blend diets. However, between 99 and 133 days of age, pigs fed the single diet utilised feed more efficiently (P < 0.001) than did pigs fed the phase-feeding and blend diets. Therefore, there was no significant effect of the feeding strategies on overall growth performance (P > 0.05) and there was no significant difference in carcass quality (P > 0.05) among treatment groups. However, it was 3.74% and 3.51% cheaper to use the blend- and single-diet feeding strategies, respectively, than it was to use a phase-feeding program (P = 0.002). The present experiment has shown that blend-feeding could be a strategy to reduce the cost of production. Feeding a single diet appears to have merit and may have appeal for certain circumstances; however, it would need to be investigated further before being implemented commercially.

The response of entire male and female pigs from 20 to 100-kg liveweight to dietary available lysine

Two experiments were conducted to determine the responses of entire male and female pigs of the Australian Pig Improvement Co. genotype to dietary lysine. In Experiment 1, a total of 350 [Large White × (Landrace × Duroc)] entire male and female pigs weighing 22.3 ± 0.16 kg (mean ± s.e.m.) were used in a 2 by 5 factorial design with the main treatments being sex (entire males and females) and five levels of standardised ileal digestible (SID) lysine to digestible energy ratio (0.6, 0.7, 0.8, 0.9 and 1.0 g SID lysine/MJ DE). In Experiment 2, a total of 420 [Large White × (Landrace × Duroc)] entire male and female pigs weighing 49.6 ± 0.34 kg (mean ± s.e.m.) were used in a 2 by 5 factorial design with the main treatments being sex (entire males and females) and five levels of SID lysine to MJ DE ratio (0.4, 0.5, 0.6, 0.7 and 0.8 g). From 20 to 50 kg liveweight (LW), entire males had a similar average daily gain (ADG), lower feed intake (FI, P < 0.001) and better feed to gain ratio (F : G, P < 0.001) compared with females. From 50 to 100 kg LW, entire males had a higher ADG (P < 0.001), similar FI and improved F : G ratio (P < 0.001) compared with females. Data were subjected to the quadratic response model to determine optimum SID lysine requirement for maximum ADG and minimum F : G for the weight ranges 20–35, 35–50, 50–65, 65–80, and 80 to 95 kg LW. For male pigs, maximum ADG was achieved at SID lysine levels of 1.00, 0.87, 0.72, 0.67 and 0.63 g/MJ DE, respectively. Minimum F : G was achieved at SID lysine levels of 1.00, 0.87, 0.80, 0.69 and 0.63 g/MJ DE for the respective weight ranges. For female pigs, maximum ADG was achieved at SID lysine levels of 0.90, 0.84, 0.67, 0.63 and 0.58 g/MJ DE. Minimum F : G for females was achieved at SID lysine levels of 0.86, 0.85, 0.64, 0.66 and 0.40 g/MJ DE for the respective weight ranges. The results suggest that this Australian genotype requires greater dietary SID lysine in the growing and finishing phase than the levels currently used by the Australian industry.

Light Emission from Intrinsic and Doped Silicon-Rich Silicon Oxide: from the Visible to 1.6 ΜM

Silicon-rich silicon oxide (SRSO) films were prepared by thermal oxidation (700°C-950°C) of electrochemically etched crystalline silicon (c-Si). The annealing-oxidation conditions are responsible for the chemical and structural modification of SRSO as well as for the intrinsic light-emission in the visible and near infra-red spectral regions (2.0–1.8 eV, 1.6 eV and 1.1 eV). The extrinsic photoluminescence (PL) is produced by doping (via electroplating or ion implantation) with rare-earth (R-E) ions (Nd at 1.06 μm, Er at 1.5 μm) and chalcogens (S at ∼1.6 μm). The impurities can be localized within the Si grains (S), in the SiO matrix (Nd, Er) or at the Si-SiO interface (Er). The Er-related PL in SRSO was studied in detail: the maximum PL external quantum efficiency (EQE) of 0.01–0.1% was found in samples annealed at 900°C in diluted oxygen (∼ 10% in N2). The integrated PL temperature dependence is weak from 12K to 300K. Light emitting diodes (LEDs) with an active layer made of an intrinsic and doped SRSO are manufactured and studied: room temperature electroluminescence (EL) from the visible to 1.6 μmhas been demonstrated.

Increasing power in randomized trials with right censored outcomes through covariate adjustment

Targeted maximum likelihood methodology is applied to provide a test that makes use of the covariate data that are commonly collected in randomized trials, and does not require assumptions beyond those of the logrank test when censoring is uninformative. Under informative censoring, the logrank test is biased, whereas the test provided in this article is consistent under consistent estimation of the censoring mechanism or the conditional hazard for survival. Two approaches based on this methodology are provided: (1) a substitution-based approach that targets treatment and time-specific survival from which the logrank parameter is estimated, and (2) directly targeting the logrank parameter.

Covariate adjustment in randomized trials with binary outcomes: targeted maximum likelihood estimation

Covariate adjustment using linear models for continuous outcomes in randomized trials has been shown to increase efficiency and power over the unadjusted method in estimating the marginal effect of treatment. However, for binary outcomes, investigators generally rely on the unadjusted estimate as the literature indicates that covariate-adjusted estimates based on the logistic regression models are less efficient. The crucial step that has been missing when adjusting for covariates is that one must integrate/average the adjusted estimate over those covariates in order to obtain the marginal effect. We apply the method of targeted maximum likelihood estimation (tMLE) to obtain estimators for the marginal effect using covariate adjustment for binary outcomes. We show that the covariate adjustment in randomized trials using the logistic regression models can be mapped, by averaging over the covariate(s), to obtain a fully robust and efficient estimator of the marginal effect, which equals a targeted maximum likelihood estimator. This tMLE is obtained by simply adding a clever covariate to a fixed initial regression. We present simulation studies that demonstrate that this tMLE increases efficiency and power over the unadjusted method, particularly for smaller sample sizes, even when the regression model is mis-specified.

Ractopamine supplementation increases lean deposition in entire and immunocastrated male pigs

Sixty entire male pigs (Large White × Landrace × Duroc crossbred) were individually reared from 45 to 114 kg liveweight in a 2 by 3 factorial experiment to determine the interactive effects of sex (entire male pigs v. male pigs immunologically castrated using Improvac with vaccinations administered at 13 weeks of age and 5 weeks before slaughter) and a ractopamine feeding program (constantly fed 0 or 5 ppm ractopamine for 26 days before slaughter v. a step-up program where 5 ppm of ractopamine was fed for 14 days followed by 10 ppm ractopamine for the final 12 days before slaughter) on growth performance, carcass composition and pork quality. Following the second vaccination, immunocastrated pigs ate more (P < 0.001) and grew faster (P < 0.05) than entire male pigs without affecting feed conversion efficiency. Dietary ractopamine supplementation for the last 26 days before slaughter improved feed conversion ratio (P = 0.024) and daily gain (P = 0.046). Dietary ractopamine supplementation also increased carcass total tissue (P = 0.023) and total lean (P = 0.027) content without affecting the objective meat quality (P > 0.05) in both entire and immunocastrated male pigs. The effects of dietary ractopamine and immunocastration were additive, such that pigs that were immunocastrated and received ractopamine grew 18% faster than control entire males. However, a step-up program of ractopamine supplementation did not provide further improvements in growth performance and carcass composition when compared with constant 5 ppm ractopamine supplementation. These findings indicate that ractopamine supplementation improved growth performance in entire and immunocastrated male pigs, thereby offering a means of improving growth performance of entire males without detrimental effects on pork quality.

Dispersion management using betatron resonances in an ultracold-atom storage ring

Particles circulating at specific velocities in a storage ring can undergo betatron resonances at which static perturbations of the particles' orbit yield large transverse (betatron) oscillations. We have observed betatron resonances in an ultracold-atom storage ring and found these resonances to cause the near-elimination of the longitudinal dispersion of atomic beams propagating at resonant velocities. This effect can improve atom-interferometric devices. Both the resonant velocities and the resonance strengths were varied by deliberate modifications to the storage ring.

Bose-Einstein condensation in a circular waveguide

We have produced Bose-Einstein condensates in a ring-shaped magnetic waveguide. The few-millimeter diameter, nonzero-bias ring is formed from a time-averaged quadrupole ring. Condensates that propagate around the ring make several revolutions within the time it takes for them to expand to fill the ring. The ring shape is ideally suited for studies of vorticity in a multiply connected geometry and is promising as a rotation sensor.

Direct nondestructive imaging of magnetization in a spin-1 Bose-Einstein gas

Polarization-dependent phase-contrast imaging is used to resolve the spatial magnetization profile of an optically trapped ultracold gas. This probe is applied to Larmor precession of degenerate and nondegenerate spin-1 87Rb gases. Transverse magnetization of the Bose-Einstein condensate persists for the condensate lifetime, with a spatial response to magnetic field inhomogeneities consistent with a mean-field model of interactions. In comparison, the magnetization of the non-condensed gas decoheres rapidly. Rotational symmetry implies that the Larmor frequency of a spinor condensate be density independent, and thus suitable for precise magnetometry with high spatial resolution.

Genetic and phenotypic relationships between insulin-like growth factor-I (IGF-I) and net feed intake, fat, and growth traits in Angus beef cattle

Insulin-like growth factor-I (IGF-I) concentration measured in the blood plasma of 6520 seedstock Angus beef cattle (3622 bulls and 2898 heifers) from eastern Australia between 2002 and 2004 was used to estimate the heritability of IGF-I and phenotypic and genetic correlations with net feed intake (NFI) and other production traits. The average concentration of IGF-I was 314 ng/mL measured at the average age of 242 days. A moderate heritability of 0.35 was estimated for IGF-I. IGF-I was further defined as being measured either at, or prior to, weaning (average age of 201 days) or post-weaning (average age 310 days). The genetic correlation between IGF-I recorded at the different ages was 1.0 ± 0.04. IGF-I and NFI were found to have a genetic correlation of 0.41 ± 0.21. IGF-I had positive genetic correlations of 0.22 ± 0.14, 0.19 ± 0.14, and 0.26 ± 0.15 with ultrasound-scanned subcutaneous fat depth at the rump (P8) and 12/13th rib (RIB) sites and intramuscular fat % (IMF), respectively. Corresponding phenotypic correlations were 0.14, 0.13, and 0.12, respectively, for P8, RIB, and IMF. IGF-I had low to moderate negative genetic correlations with growth traits. Direct genetic correlations for IGF-I of –0.22 ± 0.08, –0.17 ± 0.09 and –0.10 ± 0.14 were estimated with birth (BWT), 200-day (WT200), and 400-day (WT400) weights, respectively. Genetic correlations between the direct component of IGF-I and maternal components of BWT and WT200 were 0.15 ± 0.13 and 0.31 ± 0.11, respectively. Phenotypic correlations of the direct component of IGF-I with the direct components of BWT, WT200, and WT400 were –0.10, 0.06, and 0.16, respectively. Ultrasound-scanned eye muscle area (EMA) and IGF-I had genetic and phenotypic correlations of –0.22 ± 0.15 and 0.13, respectively. This study showed that IGF-I is heritable and genetically correlated with important production traits. The genetic correlations indicate that selection for lower IGF-I concentrations would result in cattle that have lower NFI (i.e. more feed efficient), are leaner, with increased growth, and possibly decreased maternal weaning weight.

The acute physiological and mood effects of tea and coffee: the role of caffeine level

The objective of this study was to determine the effect of caffeine level in tea and coffee on acute physiological responses and mood. Randomised full crossover design in subjects after overnight caffeine abstention was studied. In study 1 (n = 17) the caffeine level was manipulated naturalistically by preparing tea and coffee at different strengths (1 or 2 cups equivalent). Caffeine levels were 37.5 and 75 mg in tea, 75 and 150 mg in coffee, with water and no-drink controls. In study 2 (n = 15) caffeine level alone was manipulated (water, decaffeinated tea, plus 0, 25, 50, 100, and 200 mg caffeine). Beverage volume and temperature (55 degrees C) were constant. SBP, DBP, heart rate, skin temperature, skin conductance, and mood were monitored over each 3-h study session. In study 1, tea and coffee produced mild autonomic stimulation and an elevation in mood. There were no effects of tea vs. coffee or caffeine dose, despite a fourfold variation in the latter. Increasing beverage strength was associated with greater increases in DBP and energetic arousal. In study 2, caffeinated beverages increased SBP, DBP, and skin conductance and lowered heart rate and skin temperature compared to water. Significant dose-response relationships to caffeine were seen only for SBP, heart rate, and skin temperature. There were significant effects of caffeine on energetic arousal but no consistent dose-response effects. Caffeinated beverages acutely stimulate the autonomic nervous system and increase alertness. Although caffeine can exert dose-dependent effects on a number of acute autonomic responses, caffeine level is not an important factor. Factors besides caffeine may contribute to these acute effects.

Association of neutropenia in systemic lupus erythematosus (SLE) with anti-Ro and binding of an immunologically cross-reactive neutrophil membrane antigen

SLE is associated with the production of autoantibodies to self-constituents. In particular, certain ribonucleoprotein particles are targeted. Despite the multitude of autoantibodies produced and the remarkable concentrations of these antibodies in the sera of SLE patients, there have been little data that the autoantibodies found in SLE are involved in the pathogenesis of disease or its manifestations. The present work demonstrates that anti-Ro (or SSA) is associated with granulocytopenia, binds the surface of granulocytes and fixes complement to this membrane surface. Binding is a property of anti-Ro Fab fragments and can be inhibited by 60-kD Ro. However, the antigen bound on the surface of granulocytes is a 64 000 mol. wt protein that is a novel autoantigen in SLE. As suggested by inhibition studies, sequence identity between 60-kD Ro and eight tandem repeats in the 64-kD antigen may be responsible for the observed serologic cross-reactivity. These data imply that anti-Ro antibodies that also bind the 64-kD protein mediate neutropenia in patients with SLE.

A novel glycosulfopeptide binds to P-selectin and inhibits leukocyte adhesion to P-selectin

P-selectin glycoprotein ligand-1 (PSGL-1) is a dimeric membrane mucin on leukocytes that binds selectins. The molecular features of PSGL-1 that determine this high affinity binding are unclear. Here we demonstrate the in vitro synthesis of a novel glycosulfopeptide (GSP-6) modeled after the extreme N terminus of PSGL-1, which has been predicted to be important for P-selectin binding. GSP-6 contains three tyrosine sulfate (TyrSO(3)) residues and a monosialylated, core 2-based O-glycan with a sialyl Lewis x (C2-O-sLe(x)) motif at a specific Thr residue. GSP-6 binds tightly to immobilized P-selectin, whereas glycopeptides lacking either TyrSO(3) or C2-O-sLe(x) do not detectably bind. Remarkably, an isomeric glycosulfopeptide to GSP-6, termed GSP-6', which contains sLe(x) on an extended core 1-based O-glycan, does not bind immobilized P-selectin. Equilibrium gel filtration analysis revealed that GSP-6 binds to soluble P-selectin with a K(d) of approximately 350 nM. GSP-6 (<5 microM) substantially inhibits neutrophil adhesion to P-selectin in vitro, whereas free sLe(x) (5 mM) only slightly inhibits adhesion. In contrast to the inherent heterogeneity of post-translational modifications of recombinant proteins, glycosulfopeptides permit the placement of sulfate groups and glycans of precise structure at defined positions on a polypeptide. This approach should expedite the probing of structure-function relationships in sulfated and glycosylated proteins, and may facilitate development of novel drugs to treat inflammatory diseases involving P-selectin-mediated leukocyte adhesion.

Probing nonequilibrium electron distributions in gold by use of second-harmonic generation

Second-harmonic radiation is generated at a gold surface by use of a laser pulse that is varied in duration from 14 to 29 fs and in intensity from 10(9) to 10(11)W/cm(2) . At laser intensities below 10(10)W/cm(2) , the second-harmonic signal has the expected quadratic dependence on pump-laser intensity; however, at higher intensities, the dependence is supraquadratic. This difference arises because the leading edge of the laser pulse interacts significantly with the gold electrons to create a nonequilibrium, photoexcited distribution. The second-harmonic generation process occurs before electron-electron or electron-phonon collisions can equilibrate the distribution and therefore serves as a probe of the nonequilibrium distribution.

A spun-column assay for determination of leptin binding in serum

Serum collected from 27 patients was assayed simultaneously using a spun-column assay (SPC) and a traditional exclusion gel-filtration assay (GFC) to determine specific leptin binding. The levels of serum leptin binding determined by either assay correlated inversely with serum leptin levels (SPC, r = 0.63, P < 0.001; GFC, r = 0.79, P < 0.0001). Although specific leptin binding as determined by the traditional exclusion gel-filtration assay was generally higher than that obtained by the spun-column assay (mean = 18.3% vs 14.0%, P < 0. 02, respectively); the values obtained between the two assay methods were highly correlative (r = 0.89, P < 0.0001). By varying either the amount of 125I-leptin or the amount of competitor, analysis was carried out using the spun-column assay to determine the intrinsic properties of serum leptin binding. Results yielded a Kd = 0.3 nM, where each variable amount of leptin or competitor was carried out in duplicate. The complete analysis was carried out in the time that it typically takes for a single sample determination by the traditional exclusion gel-filtration assay. We conclude that the "spun-column" assay is a useful method for rapid and accurate quantification of leptin binding in serum.

The effects of black tea and other beverages on aspects of cognition and psychomotor performance

Nineteen healthy volunteers ingested 400 ml black tea, coffee, caffeinated water, decaffeinated tea or plain water on three occasions through the day (0900, 1400 and 1900 hours). A 2 x 2 factorial design with caffeine (0, 100 mg) and beverage type (water, tea) was employed, with coffee (100 mg caffeine) as a positive internal control, based on a five-way crossover. A psychometric test battery comprising critical flicker fusion (CFF), choice reaction time (CRT), short-term memory (STM) and subjective sedation (LARS) was performed at regular intervals throughout the day, and intensively so immediately following each beverage. Consumption of tea compared to water was associated with transient improvements in performance (CFF) within 10 min of ingestion and was not affected by the time of day. Caffeine ingestion was associated with a rapid (10 min) and persistent reduction in subjective sedation values (LARS), again independent of time of day, but did not acutely alter CFF threshold. Over the whole day, consumption of tea rather than water, and of caffeinated compared to decaffeinated beverages, largely prevented the steady decline in alertness (LARS) and cognitive capacity observed with water ingestion. The effects of tea and coffee were similar on all measures, except that tea consumption was associated with less variation in CFF over the whole day. No significant treatment effects were apparent in the data for the STM. Tea ingestion is associated with rapid increases in alertness and information processing capacity and tea drinking throughout the day largely prevents the diurnal pattern of performance decrements found with the placebo (no caffeine) condition. It appears that the effects of tea and coffee were not entirely due to caffeine per se; other factors either intrinsic to the beverage (e.g. sensory attributes or the presence of other biologically active substances) or of a psychological nature (e.g. expectancy) are likely to play a significant role in mediating the responses observed in this study.

Molecular cloning and expression of human and mouse tyrosylprotein sulfotransferase-2 and a tyrosylprotein sulfotransferase homologue in Caenorhabditis elegans

Tyrosine O-sulfation, a common post-translational modification in eukaryotes, is mediated by Golgi enzymes that catalyze the transfer of the sulfuryl group from 3'-phosphoadenosine 5'-phosphosulfate to tyrosine residues in polypeptides. We recently isolated cDNAs encoding human and mouse tyrosylprotein sulfotransferase-1 (Ouyang, Y. B., Lane, W. S., and Moore, K. L. (1998) Proc. Natl. Acad. Sci. U. S. A. 95, 2896-2901). Here we report the isolation of cDNAs encoding a second tyrosylprotein sulfotransferase (TPST), designated TPST-2. The human and mouse TPST-2 cDNAs predict type II transmembrane proteins of 377 and 376 amino acid residues, respectively. The cDNAs encode functional N-glycosylated enzymes when expressed in mammalian cells. In addition, preliminary analysis indicates that TPST-1 and TPST-2 have distinct specificities toward peptide substrates. The human TPST-2 gene is on chromosome 22q12.1, and the mouse gene is in the central region of chromosome 5. We have also identified a cDNA that encodes a TPST in the nematode Caenorhabditis elegans that maps to the right arm of chromosome III. Thus, we have identified two new members of a class of membrane-bound sulfotransferases that catalyze tyrosine O-sulfation. These enzymes may catalyze tyrosine O-sulfation of a variety of protein substrates involved in diverse physiologic functions.

Tyrosylprotein sulfotransferase: purification and molecular cloning of an enzyme that catalyzes tyrosine O-sulfation, a common posttranslational modification of eukaryotic proteins

Tyrosine O-sulfation is a common posttranslational modification of proteins in all multicellular organisms. This reaction is mediated by a Golgi enzyme activity called tyrosylprotein sulfotransferase (TPST) that catalyzes the transfer of sulfate from 3'-phosphoadenosine 5'-phosphosulfate to tyrosine residues within acidic motifs of polypeptides. Tyrosine O-sulfation has been shown to be important in protein-protein interactions in several systems. For example, sulfation of tyrosine residues in the leukocyte adhesion molecule P-selectin glycoprotein ligand 1 (PSGL-1) is required for binding to P-selectin on activated endothelium. In this report we describe the purification of TPST from rat liver microsomes based on its affinity for the N-terminal 15 amino acids of PSGL-1. We have isolated human and mouse TPST cDNAs that predict type II transmembrane proteins of 370 amino acid residues with almost identical primary structure. The human cDNA encodes a fully functional N-glycosylated enzyme with an apparent molecular mass of approximately 54 kDa when expressed in mammalian cells. This enzyme defines a new class of Golgi sulfotransferases that may catalyze tyrosine O-sulfation of PSGL-1 and other protein substrates involved in diverse physiologic functions including inflammation and hemostasis.

Structure and function of P-selectin glycoprotein ligand-1

Directed emigration of leukocytes into inflammatory sites and lymphatic tissues is orchestrated by the regulated expression of adhesion and signaling molecules on cells within the vasculature. The selectin family of adhesion molecules that are expressed on activated endothelial cells (E-selectin and P-selectin), activated platelets (P-selectin), and peripheral blood leukocytes (L-selectin), mediate tethering and rolling of leukocytes to the vessel wall in the microcirculation. Selectins promote these interactions by binding to glycoconjugate ligands expressed on apposing cells. Selectin-mediated rolling is a prerequisite for firm adhesion and subsequent transendothelial migration of leukocytes into tissues. This review will focus on the structure and function of P-selectin glycoprotein ligand-1 (PSGL-1, CD162). PSGL-1 is a disulfide-bonded homodimeric mucin-like glycoprotein on leukocytes that interacts with P-, L-, and E-selectin. PSGL-1 mediates leukocyte-endothelial and leukocyte-platelet adhesion by binding to P-selectin expressed on activated endothelium and platelets and PSGL-1 mediates leukocyte-leukocyte adhesion by binding to L-selectin expressed on apposing leukocytes. PSGL-1 is unique in that it is the only selectin glycoprotein ligand that has been directly demonstrated to mediate cell-cell adhesion in vitro and in vivo.

Drug treatment of migraine: Part II. Preventive therapy

In most cases, successful preventive therapy for migraines requires daily medication for months or years. Perimenstrual use of a preventive agent is a common exception. Preventive therapy is usually undertaken in patients who have more than two headache episodes per month or those very much disabled by headaches. Beta blockers are usually the first choice for preventive therapy, and amitriptyline is also commonly used. Despite widespread use of calcium channel blockers for prevention of migraine, their benefits are controversial. Although effective for prevention of migraine, methysergide and phenelzine are usually relegated to last-resort use because of potentially serious side effects. The migraine patient who is refractory to standard preventive therapy may have rebound headache related to overuse of abortive migraine medications, or concomitant psychopathology.

Drug treatment of migraine: Part I. Acute therapy and drug-rebound headache

Most migraine patients need only abortive treatment for their headaches. By the time they present to a physician, they have already tried many over-the-counter medications for headache relief. Prioritizing treatment according to headache severity and associated symptoms will help the physician determine the most appropriate medications to use. Narcotics should be reserved for use only in patients unresponsive to adequate trials of non-narcotic agents. In some patients, the recurrent nausea and vomiting can be as disabling as the pain; antiemetic agents are an important adjunct to analgesic therapy in these patients. Sumatriptan and dihydroergotamine are more expensive than other migraine agents but have distinct therapeutic advantages in patients with moderate to severe headaches. Some patients experience rebound headache from overuse of analgesics and other headache medications. Educating patients about self-help measures and avoidance of triggers is an important element in the effective management of migraine headaches.