Metabolomic analysis reveals linkage between chemical composition and sensory quality of different floral honey samples

Honey has a distinct flavor characterized by various volatiles and non-volatiles from diverse origins. In this study, metabolomics combined with sensory analysis was performed to identify relationships between chemical profile and sensory quality of honey. Targeted metabolomic analysis was conducted to determine volatile and non-volatile profiles of seven different honey. Volatile profile was analyzed using headspace solid-phase microextraction (HS-SPME) coupled to GC - MS. LC - MS/MS, HPLC - UV, and HPLC-RI were employed to analyze flavonoids, organic acids, and sugars, respectively. Authentic standards were utilized for confirmation of metabolites. Sensory evaluation included quantitative descriptive analysis and consumer acceptance test. The results showed that sucrose (sweetness) was responsible for a positive hedonic perception, while organic acids and flavonoids (sourness, astringency, bitterness) negatively affected consumer acceptance. Volatiles with floral notes (e.g. decyl formate) were preferred, but others with off-flavors (e.g. 2-methylbenzofuran) were not preferred by consumers. Flavor familiarity was strongly correlated with the consumer acceptance of honey, indicating that the balance between volatiles and non-volatiles is significant for honey flavor quality. This work demonstrates the role of key flavor compounds in honey quality, and may be applicable to the quality control of honey.

Dosimetric Quality of Artificial Intelligence Based Organ at Risk Segmentation

PURPOSE/OBJECTIVE(S)

to compare dosimetric parameters between Artificial intelligence (AI) generated organ at risks (OAR) and Radiation Oncologist approved OARs and evaluation of appropriateness unedited AI- OARs in routine clinical plan optimization and evaluation.

MATERIALS/METHODS

The OARs (lung, spinal cord and heart) for twenty SBRT (stereotactic body radiotherapy) lung CT simulation datasets were derived by AI based segmentation algorithms. These AI- OARs were edited by a staff Radiation Oncologist and then subjected to our SBRT peer-review process at our institution. A SBRT plan based on the approved contours was created. Dosimetric parameters for the unedited AI-OARs and edited physician-approved OARs were then compared.

RESULTS

Lung V20 differences between AI- OAR and physician- OAR varied from 0.01% - 0.7% with a mean value of 0.1% difference (p-value 0.004). Spinal cord D0.03cc varied from 0.02 Gy - 0.9 Gy with a mean value of 0.3 Gy difference (p-value 0.002). Heart D0.03cc varied from 0.01 Gy - 4.3 Gy with mean value 0.9 Gy difference (p-value 0.02).

CONCLUSION

Dosimetric parameters for AI-based lung, spinal cord and heart OARs vs physician approved OARs were different, overall, the differences were generally small. These differences are likely on par with inter-observer differences seen between individual radiation oncologists. Unedited OARs have the promise for routine use in plan optimization and evaluation to further improve efficiency.

Clinical Outcomes for Patients with Brain Metastases from Upper Gastrointestinal Cancer Treated with Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Prior studies have reported outcomes for brain metastases from gastrointestinal (GI) primary cancers treated with stereotactic radiosurgery (SRS); however, most include a majority of colorectal cancer. Few studies specifically evaluate SRS treatment response for brain metastases from upper GI cancers. We report our institutional outcomes for patients with upper GI cancers who were treated with SRS for brain metastases.

MATERIALS/METHODS

Patients with an upper GI cancer who underwent SRS for brain metastases between 1991 and 2021 were retrospectively reviewed from a single institution IRB-approved database. The primary endpoint was local failure (LF) and secondary endpoint was overall survival (OS). LF was estimated using the Cumulative Incidence Function with death as a competing risk. Survival analysis was performed with the Kaplan-Meier Method. Predictors of cumulative incidence of LF were assessed using competing risk regression.

RESULTS

Forty-nine patients with 107 brain metastases were analyzed. Forty-two (86%) patients were male. The median follow-up time was 6.7 months (range: 0.4-61.7 months) and median OS was 7.5 months (range: 0.9-61.7 months). The median Karnofsky Performance Score (KPS) was 80 (range: 40-100). The primary disease site was esophagus in 87 (81%) lesions, pancreas in 10 (9.3%) lesions, stomach in 5 (4.7%) lesions, liver in 2 (1.9%) lesions, gallbladder in 2 (1.9%) lesions, and small intestine in 1 (0.9%) lesion. The median metastasis size was 1.4 cm (range: 0.3-6.7 cm). The median prescription dose and fraction number were 24 Gy (range: 14-30 Gy) and 1 fraction (range: 1-2 fractions), respectively. The cumulative incidence of LF at 6 and 12 months was 5.6% (95% CI: 2.3-11%) and 12% (95% CI: 6.9-20%), respectively. Overall survival at 6 and 12 months was 59% (95% CI: 50-69%) and 35% (95% CI: 27-46%), respectively. On univariate analysis, female gender (HR = 0.19, 95% CI: 0.06-0.61, p = 0.005), Black race (HR = 0.09, 95% CI: 0.03-0.23, p = <0.001), and larger tumors (HR = 1.35, 95% CI: 1.03-1.78, p = 0.03) were significantly associated with local failure.

CONCLUSION

SRS for brain metastases from upper GI cancers is an appropriate treatment option and provides excellent local control. Unlike prior studies that have reported lower local control rates for all GI cancers with brain metastases treated with SRS, our data show that local failure rates in brain metastases from upper GI cancers specifically are more consistent with previously published data from other disease sites. Further studies evaluating SRS treatment response for brain metastases from GI cancers should separate upper GI and lower GI cancers.

Patient-Free Simulation: Analysis of Hospitalized Patients Treated without CT Simulation

PURPOSE/OBJECTIVE(S)

Palliative radiation therapy (RT) can be a necessary element of treatment for hospitalized cancer patients who may be critically ill. We have implemented patient-free simulation machine starts using existing diagnostic imaging for treatment planning, eliminating the need for simulation. We hypothesize machine starts reduce time in the department without detriment to clinical outcomes.

MATERIALS/METHODS

An IRB-approved database of patients receiving RT was queried for hospitalized patients treated with a machine start. Variables including time on machine and in department, and clinical outcomes were collected. A binary clinical endpoint variable indicated whether the goal of RT was achieved (extubation, hemostasis, etc.). A similar cohort of inpatients receiving CT simulation and mediastinal RT was compared with the machine start group. Mann-Whitney U test was used for comparison between groups. Hypothesis testing for proportions was used to compare patients meeting clinical endpoints.

RESULTS

A total of 23 patients were treated with 25 machine starts. The median age was 65 (range 43-82) and median KPS was 50. A total of 15 patients were in the intensive care unit of which 12 were mechanically ventilated (MV). The most common histology was NSCLC (14). RT was most commonly 8-10 Gy in 1 fraction (88%, range 7-30 Gy in 1-10 fractions). Field arrangement was equally weighted AP/PA fields in 84%. Treated sites were mediastinum (17), bone (3), abdomen/pelvis (2), neck (2), and brain (1). Diagnostic CT of the treatment area was obtained a median of 6 days prior to RT (0-57 days). Machine starts within 4 days of admission were significantly more likely to meet the intended clinical endpoint (87% vs 47%, p = 0.02). On day of machine start, patients' median time in the department was 32 minutes (10-141 min). Of machine starts with treatment times available (22), median time in the LINAC vault was 15 minutes (5-31 min). The median shifts from the initial CBCT were 0.9 cm in the superior-inferior direction (0-2.7 cm), left-right 0.9 cm (0-5.9 cm) and anterior-posterior 0.5 cm (0-3 cm). One patient required repeat CBCT after initial shifts. In a similar cohort of patients who underwent CT simulation followed by RT to the mediastinum, the average time in the department was 122 minutes, compared with 45 minutes for machine start patients treated to the mediastinum (p = 0.02). Primary clinical endpoint was achieved in 65% of machine starts. 61% of patients clinically improved and were stable for discharge. Of the MV patients, 42% were successfully extubated and 58% were discharged. Of patients who died (74%), average time to death was 53 days after RT (4-126 days). Among the MV subgroup, 83% died an average of 49 days from RT (4-126 days).

CONCLUSION

Machine starts are a timely and accurate alternative to traditional planning with CT simulation that results in approximately 60% less time in the department. This is an acceptable RT planning technique for a population that demands greater medical attention and resources.

Results of a Phase I Trial of Dose Escalation for Preoperative Stereotactic Radiosurgery for Patients with Large Brain Metastases

PURPOSE/OBJECTIVE(S)

Single session stereotactic radiosurgery (SRS) alone for brain metastases larger than 2 cm in diameter results in unsatisfactory local control. Surgical resection alone also produces unreliable local control and perioperative radiation is required. We conducted a prospective phase I trial (NCT01891318) for brain metastases greater than 2 cm to determine the safety of preoperative SRS at escalating doses followed by surgical resection.

MATERIALS/METHODS

Radiosurgery dose started at RTOG 9005 dose levels for the 3 cohorts based on maximum tumor diameter of the index lesion: 18 Gy for >2-3 cm, 15 Gy for >3-4 cm, and 12 Gy >4-6 cm. Concurrent SRS alone to other smaller lesions was allowed using standard RTOG dose. Dose limiting toxicity (DLT) was defined as grade 3 or greater acute toxicity within 3 to 4 months after SRS. Patients underwent surgical resection within 2 weeks and were followed with imaging and neurological evaluations every 3 months.

RESULTS

A total of 35 patients were enrolled into the trial (see Table 1 below). The median age was 63, and median interval between SRS and surgery was 2 days. The most common histology was non-small cell lung cancer (57.1%), followed by breast cancer (14.3%). For tumor size >2-3 cm, patients were enrolled up to the 2nd dose level (21 Gy); for >3-4 cm and >4-6 cm cohorts the 3rd dose level (21 Gy and 18 Gy, respectively) was reached. There was a total of 3 DLTs: 2 in the >3-4 cm cohort and 1 in the >4-6 cm cohort (Table 1). The maximum tolerable dose (MTD) was 18 Gy (2nd dose level) for >3-4 cm, and 18 Gy (3rd dose level) for >4-6 cm. With a median follow-up of 64 months, the 6- and 12-month local control rates were 88.8% and 79.1%, respectively. The 6- and 12-month distant brain control was 63.1% and 55.3%, respectively. Overall survival at 6 and 12 months was 82.9% and 59.0%. The rate of leptomeningeal disease (LMD) at 2 years was 0%.

CONCLUSION

Preoperative SRS with dose escalation followed by surgical resection for brain metastases greater than 2 cm in size results in local control comparable to postoperative SRS or whole-brain radiation therapy and demonstrates acceptable acute toxicity. The Phase II portion of the trial will be conducted at the maximum tolerated SRS doses.

Three Decade Single-Institution Experience of Safety and Efficacy of Radiotherapy and Adjuvant Chemotherapy for Young Adult Patients with Medulloblastoma

PURPOSE/OBJECTIVE(S)

The rarity of medulloblastoma in the adult population limits information on optimal treatment and clinical outcomes. Adjuvant chemoradiation has been correlated to improved overall survival (OS) in a recent National Cancer Database (NCDB) analysis. We performed a retrospective safety and efficacy analysis of radiation (RT) +/- adjuvant chemotherapy (aCTH) in young adult patients with medulloblastoma to better understand outcomes, prognostic factors, and possibly optimal treatment strategies.

MATERIALS/METHODS

We conducted an IRB-approved retrospective chart review on young adult (age ≥18 - 39 years old) patients with medulloblastoma treated at our institution (1992-2018) with a minimum follow-up of 6 months from completion of therapy. We gathered data on patient and disease characteristics, treatment, and clinical outcomes, including OS, progression-free survival (PFS), local control (LC), and freedom from distant metastasis (FDM). We employed Cox regression model for univariable and multivariable analyses and Kaplan-Meier (KM) test methods for survival analyses, using JMP version 15.0 software.

RESULTS

Thirty-one patients were treated with postoperative RT including craniospinal irradiation (median dose: 2340 cGy/13 fractions) followed by tumor bed/posterior fossa (median total dose: 5580 cGy/31 fractions) either alone (n = 9; 29%) or with adjuvant chemotherapy (aCTH: n = 22; 71%); mostly as per COG A9961 Regimen A: oral lomustine, intravenous cisplatin, and intravenous vincristine (n = 12). 54.6% (n = 12) were known to complete the full aCTH course. Common RT acute toxicities included G1-2 nausea and/or vomiting (N/V; n = 8) and G1-2 fatigue (n = 6). Common aCTH acute toxicities included G1-2 N/V (n = 7) and peripheral neuropathy: G1-2 (n = 6) and G3 (n = 3). Late adverse events were primarily G1-2 peripheral neuropathy and gait imbalance (22.6%), G1-2 hormonal disturbances (19.4%) and G1-2 neurocognitive impairment (16.1%). Male patients had worse OS, PFS, FDM, and LC. Age at diagnosis, tumor location (lateral vs. central), and completion of aCTH course were shown on uni- and multi-variable analysis to be significantly associated with OS; p<0.05. KM survival analysis revealed superior 10-year PFS and OS in patients who completed aCTH compared to those who received RT alone or did not complete aCTH: 72.9% vs 59.3% vs 42%, p = 0.461, and 74.1% vs 63.5% vs 40%, p = 0.033, respectively. A similar trend was noted for LC and FDM.

CONCLUSION

Our series provides a report of acute and late side effects of treatment of young adult patients with medulloblastoma. Significant OS and PFS advantage are seen of aCTH completion in this patient population. Since optimal treatment of these patients is still an unmet need, prospective studies for this rare disease entity are needed.

Development of an RPA for Prediction of Radiation Necrosis Following Single Fraction Gamma Knife Radiosurgery for Brain Metastases

PURPOSE/OBJECTIVE(S)

Radiation necrosis (RN) is a potential complication following treatment of brain metastases with stereotactic radiosurgery (SRS). Several risk factors for RN have been reported, but to our knowledge there are no recursive partitioning analysis (RPA) models to identify patients at highest risk for RN. We therefore sought to develop a predictive tool to identify patients at highest risk for the development of RN following single fraction SRS.

MATERIALS/METHODS

Patients who underwent single fraction SRS for brain metastases from 2017-2021 were identified from a single institutional IRB-approved database. Patients with concern for RN were discussed in a multi-disciplinary setting and a diagnosis of RN was made based on pathologic or radiographic findings. Cox proportional hazards regression was done to identify factors associated with RN. RPA was performed to categorize patients into distinct risk groups for RN. Variables with p<0.1 on univariate analysis from the Cox regression analysis were included in the RPA. Patients with staged SRS, incomplete treatment records, or < 3 months radiographic follow-up were excluded from the analysis.

RESULTS

The study population comprised 1,011 lesions from 283 patients with a median follow-up of 9.7 months. The majority of lesions had non-small cell lung cancer (NSCLC) (49%) as the primary site followed by breast (12%) and melanoma (11%). The median prescription dose was 24 Gy (range: 12-24 Gy). RN was diagnosed in 12.2% of lesions, of which 28% (35/123) were symptomatic RN. The median time to RN was 4.9 months. Variables identified for inclusion in the RPA included primary tumor site, use of targeted therapy, tumor location, pre-SRS hemorrhage, post-SRS hemorrhage, prior SRS to other lesions, number of SRS targets, maximum dose, maximum lesion diameter, 70% isodose line, heterogeneity index, conformality index, and gradient index. RPA identified four distinct groups. Group 1 was defined as maximum lesion diameter (MLD) <0.8 cm with primary tumor site other than breast, colorectal (CRC) or NSCLC (n = 174); group 2 was MLD <0.8 cm with breast, CRC, or NSCLC (n = 372). Group 3 was defined as MLD ≥ 0.8 cm without post-SRS hemorrhage (n = 336) and group 4 was MLD ≥0.8 cm with post-SRS hemorrhage (n = 129). Two-year RN free survival for all lesions was 82%, 100% for group 1, 89% for group 2, 76% for group 3, and 58% for group 4.

CONCLUSION

We created the first RPA predictive model for RN following single fraction SRS and identified a subgroup of patients at highest risk. This RPA can help guide clinicians when educating patients on RN risk for brain metastases.

Multi-Institutional Validation of the Recursive Partitioning Analysis for Overall Survival in Patients Undergoing Spine Radiosurgery for Spine Metastasis

PURPOSE/OBJECTIVE(S)

The recently published spine radiosurgery (sSRS) recursive partitioning analysis (RPA) for overall survival (OS) separated patients into 3 distinct prognostic groups. We sought to externally validate this RPA using 3 separate multi-institutional datasets.

MATERIALS/METHODS

A total of 444 patients were utilized to develop the recently published sSRS RPA predictive of OS in patients with spine metastases. The RPA identified three distinct prognostic classes. RPA Class 1 was defined as KPS >70 and controlled systemic disease (n = 142); RPA Class 2 was defined as KPS>70 with uncontrolled systemic disease or KPS ≤70, age ≥54 and absence of visceral metastases (n = 207); RPA Class 3 was defined as KPS ≤70 and age <54 years or KPS≤70, age ≥54 years and presence of visceral metastases (n = 95). We utilized data from 3 large tertiary care centers to independently validate this RPA. Data from each institution was utilized independently to validate the RPA to minimize confounding based on institutional differences in patient selection. A total of 1,184 patients (221 patients from institution A, 749 institution B, and 214 from institution C) were in the validation cohort and were divided based on their RPA Class. Kaplan-Meier method was used to estimate OS and log-rank test was used to compare OS between RPA classes.

RESULTS

In each of the validation cohorts, the median OS was 19.9 months (institution A), 11.0 months (institution B), and 24.4 months (institution C). The patient distribution into RPA classification based on Institution A/B/C was, Class 1 (19.4%, 15.1%, 50.5%), Class 2 (74.7%, 57.7%%, 37.9%), and Class 3 (5.9%, 27.2%%, 11.2%), respectively. The median OS for patients in the validation cohort at Institution A/B/C based on RPA class was Class 1 (54 months, 27.1 months, 50.0 months), Class 2 (15.9 months, 13.0 months, 15.1 months) and Class 3 (6.9 months, 3.5 months, 6.1 months), respectively. Patients in RPA Class 1 had a significantly better OS compared to those in Class 2 of the each of the three external institution validation cohorts (p<0.01). Similarly, patients in RPA Class 2 had a significantly better OS compared to those in Class 3 (p<0.01).

CONCLUSION

The external datasets from three large institutions independently validated the spine SRS RPA successfully for OS in patients undergoing sSRS for spinal metastases. This is the first RPA for OS to have been externally validated using multiple large datasets. Based on this validation, upfront spine SRS is strongly supported for patients in RPA Class 1 and Class 2 and is also cost effective with median OS >11 months for these patients. Patients in RPA Class 3 would benefit most from upfront conventional radiotherapy given their poor expected survival. Given successful external validation, this RPA helps guide physicians to identify those patients with spinal metastases who most benefit from sSRS.

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.

Clinical Outcomes of Patients with Brain Metastases from Colorectal Cancer Treated with Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Prior studies have demonstrated that brain metastases from gastrointestinal (GI) primary cancers have a poorer response to stereotactic radiosurgery (SRS) when compared to patients with other primary sites, with reported local control of 62-74%. We report our institutional outcomes for patients with colorectal primary cancer who were treated with SRS for brain metastases.

MATERIALS/METHODS

Patients with colorectal primary cancer who underwent SRS for brain metastases between 1989 and 2021 were retrospectively reviewed from a single institutional IRB-approved database. The primary endpoint was local failure (LF) and secondary endpoint was overall survival (OS). LF was estimated using the Cumulative Incidence Function with death as a competing risk. Survival analysis was performed using the Kaplan-Meier Method. Predictors of cumulative incidence of LF were assessed using competing risk regression.

RESULTS

The study population comprised of 109 patients with primary colorectal adenocarcinoma with 207 brain metastases. The median follow-up was 5.2 months (range: 0.4-124 months) and median OS was 5.8 months (range: 0.5-71.2 months). Fifty-two patients (48%) were male and median Karnofsky Performance Status at the time of treatment was 80 (range: 40-100). The median tumor diameter was 1.55 cm (range: 0.17-5.48 cm). The median prescription dose and number of fractions were 24 Gy (range: 11-36 Gy) and 1 fraction (range: 1-3 fractions), respectively. The cumulative incidence of LF at 3, 6, and 12 months was 9.7% (95% CI: 6.1-14%), 22% (95% CI: 16-28%), and 25% (95% CI: 20-31%), respectively. Overall survival at 3, 6, and 12 months was 81% (95% CI: 76-87%), 49% (95% CI: 42-56%) and 24% (95% CI: 18-31%), respectively. On univariate analysis, age was a significant predictor (HR = 0.96, 95% CI: 0.94-0.98), p < 0.001) of LF. Tumor size (HR = 0.80, p = 0.13) and prescription dose (HR = 1.02, p = 0.54) did not predict for LF.

CONCLUSION

To our knowledge, this is the largest series of patients with brain metastases from colorectal primary cancer treated with SRS. Compared to historical data, LF and OS in our cohort of patients was favorable. Our data confirms relatively higher rates of LF when compared to brain metastases from other primary disease sites. Further studies are warranted to identify factors that predict for LF following SRS and to develop models that predict which patients with colorectal brain metastases may be at higher risk of failure.

Frameless Fractionated Stereotactic Radiosurgery for Brain Metastases: An Institutional Series of 145 Cases

PURPOSE/OBJECTIVE(S)

Cobalt-60 stereotactic radiosurgery (SRS) typically involves single fraction treatment with frame immobilization. However, large tumor size, proximity to critical structures, and prior radiation treatment sometimes necessitate fractionated SRS with mask immobilization. We present a large institutional experience with fractionated mask-based SRS for brain metastases.

MATERIALS/METHODS

In this single-institution, IRB-approved study, all patients treated with mask-based fractionated SRS for brain metastases from March 2017 to January 2023 were identified. The primary outcomes were 1- and 2-year local control (LC) by Kaplan-Meier method.

RESULTS

A total of 118 patients with a total of 145 metastases were treated. The median follow-up time was seven months. The median age at treatment was 64.1 years (range: 26-95 years). 55.9% of patients were female. The most common primary tumors were breast (25.5%), non-small cell lung (23.4%), small-cell lung (8.3%), and melanoma (8.3%). For most cases (59.3%), the indication for fractionation was retreatment. Large size (28.3%), critical location (9.7%), and medical comorbidity (2.1%) were other indications. For all cases, the mean maximal linear size was 34.9 mm and mean target volume was 15.6 cc. For cases fractionated due to size, the mean size was 43.9 mm and mean target volume was 23.8 cc. Median total dose was 2,700 cGy (range: 1,620-3,000), and median dose per fraction (fx) was 600 cGy (range: 405-900). The most common prescriptions were 3,000 cGy/5 fx (40.0% of patients) and 2500 cGy in 500 cGy per fraction (37.2% of patients). Mean maximum dose was 4,833 cGy (range: 2,920-7,500). For 75.2% of treatments, the prescription isodose line was 50 to 59% (mean, 56.9%). Target coverage was 100% in all but one case (99%). For lesions near the brainstem, mean brainstem maximum point dose (MPD) was 9.3 Gy ± 9.8 Gy and brainstem mean dose was 3.3 Gy ± 3.3 Gy. For lesions near the optic pathway, mean optic nerve MPD was 14.4 Gy ± 9.2, optic nerve mean dose was 6.4 Gy ± 5.4 Gy, mean optic chiasm MPD was 11.7 Gy ± 7.9 Gy, and optic chiasm mean dose was 5.4 Gy ± 4.7 Gy. 1-year LC was 88.2% and 2-year LC was 80.4%. When retreatments were excluded, 1-year LC was 98.0% and 2-year LC was 98.0%. 18% of patients had acute grade 1-2 toxicities (fatigue, headache, nausea, and/or alopecia), and one patient had acute grade 3 fatigue. There was no other grade 3+ acute toxicities. 14% of patients had grade 1-2 radiation necrosis (RN); there were no cases of grade 3+ RN.

CONCLUSION

Cobalt-60 frameless fractionated SRS for brain metastases offers excellent local control, rigorous sparing of critical structures, and minimal toxicity. Frameless fractionated SRS should be considered for large, retreated, or critically located metastases.

Radio-Immune Response of Spatially Fractionated Radiotherapy for VMAT Lattice Plans

PURPOSE/OBJECTIVE(S)

To evaluate radio-immune response of spatially fractionated radiotherapy (SFRT) for large tumors using VMAT Lattice technique in terms of tumor volume under irradiation and dose fractionation schemes after SFRT.

MATERIALS/METHODS

Eleven patients treated with SFRT from a single institution were retrospectively replanned to deliver 15Gy in single fraction using Lattice technique. High dose regions are defined by multiple spheres with the diameter of 1.25 to 1.5cm and their vertex space of 3.0 to 4.0cm inside of GTV. VMAT plans with multiple arcs were developed for SFRT. Four palliative fractionation regimens of 200cGy x 12 (EQD2 = 24Gy with a/b of 10Gy), 400cGy x 5 (23.3Gy), 600cGy x 3 (24Gy) and 800cGy x2 (24Gy) and four definitive regimens of 200cGy x 24 (EQD2 = 48Gy), 400cGy x 10 (46.7Gy), 600cGy x 6 (48Gy) and 800cGy x 4 (48Gy) were considered for radiotherapy to follow SFRT. Linear quadratic (LQ) model is compared with radio-immune (RI) response model in which the activation of cytotoxic T lymphocytes, tumor immune suppression capability and immunotherapy drugs can be considered. Tumor regrowth time (TRT, time to tumor regrowth to the original volume after treatment) from each model was compared as a measure of benefit achieved from the application of SFRT.

RESULTS

The average volume of GTVs in this study was 776cc (range 58-2944cc). Three different SFRT plans (2D GRID technique with conventional collimator, 2D GRID with step & shoot IMRT, and 3D Lattice) were developed for each patient but only Lattice plans were considered in this study since they produced comparable dose modulation inside the tumor but only Lattice significantly reduced skin and critical organ dose. Radio-immune response model always expects longer TRT than LQ model. For palliative regimens, TRT of RI model is longer than that of LQ model by 14.5±9.9, 15.1±10.6, 17.2±12.4, 17.5±12.8 days for each fractionation scheme. When Lattice plan of 15Gy is delivered before the palliative treatment, the difference becomes 25.9±15.3, 31.5±23.3, 36.7±27.6, 37.5±28.5 days. The benefit of SFRT from RI response is only about 10-20 days. Interestingly, RI response is inversely proportional to tumor volume. When curative dose is considered, the difference of TRT is drastically changed from 25.9±9.8, 460.7±285.8, 1180.8±985.7, 1512.0±1327.5 days to 20.7±4.4, 449.0±411.7, 1725.4±2171.0, 3517.7±4531.7 days. The benefit of SFRT from RI response appears larger for large tumor with hypo-fractionation in definitive regimens.

CONCLUSION

The benefit of SFRT is significant for large tumors with hypo fractionation in the definitive regimens when radio-immune response model is considered which is not apparent in LQ model. Radio-immune response model may help to guide the development of successful treatment scheme large tumor volumes.

Phase II Randomized Trial of Single- vs. Two-Fraction Spine Stereotactic Radiosurgery for the Treatment of Vertebral Metastases

PURPOSE/OBJECTIVE(S)

As systemic therapies improve significantly, more patients with limited metastatic disease are undergoing spine stereotactic radiosurgery (sSRS). High dose (≥24 Gy) single fraction sSRS has been associated with a vertebral compression fracture (VCF) risk of up to 40%. Comparatively, lower dose (16-18 Gy) single fraction sSRS is associated with a fracture risk of 15-20%, with the risk increasing as the dose increases. To mitigate the risk of VCF, while optimizing higher dose delivery, some have advocated utilizing two-fraction sSRS regimen. Therefore, we designed a phase II randomized trial in which we hypothesized that single fraction sSRS is non-inferior to two-fraction sSRS with respect to VCF but offers patients greater convenience.

MATERIALS/METHODS

Inclusion criteria include age ≥18, Karnofsky performance score ≥70, vertebral metastasis from C3 to L5, maximum of three separate sites of metastases, limited paraspinal extension (<5 cm), and no rapid neurological decline. Patients must also be either Recursive Partitioning Analysis Class 1 (KPS >70 AND controlled systemic disease) or Class 2 (KPS >70, uncontrolled systemic disease OR KPS ≤70, age ≥54, no visceral metastases). Exclusion criteria include multiple primary cancers, primary neoplasm of the spine, prior surgery at the site of sSRS, spinal cord compression, bony retropulsion resulting in neurologic deficit, inability to undergo/contraindication to MRI, or diffuse multi-level metastatic spine disease. Our primary hypothesis is that single fraction sSRS (experimental arm - 16-18 Gy) is non-inferior to two fraction sSRS (standard arm - 24 Gy). Furthermore, we hypothesize that both treatment arms will have similar local control, pain control, quality of life and toxicity profiles. The primary endpoint of this trial is the development or progression of VCF at 6 months. Secondary endpoints include local control, pain control, quality of life and toxicity all of which will be assessed at 12 months. For the sample size calculation, we assumed a VCF risk of 17% in the experimental arm and a 7% risk in the standard arm. Based on these calculations, we aim to enroll 130 patients, 65 in each arm. This trial is currently enrolling patients actively, and approximately 30% of expected enrollment has been completed to date. This trial is registered on clinicaltrials.gov: NCT04218617.

RESULTS

Pending full accrual.

CONCLUSION

Pending full accrual.

Pea hull fiber supplementation does not modulate uremic metabolites in adults receiving hemodialysis: a randomized, double-blind, controlled trial

Background

Fiber is a potential therapeutic to suppress microbiota-generated uremic molecules. This study aimed to determine if fiber supplementation decreased serum levels of uremic molecules through the modulation of gut microbiota in adults undergoing hemodialysis.

Methods

A randomized, double-blinded, controlled crossover study was conducted. Following a 1-week baseline, participants consumed muffins with added pea hull fiber (PHF) (15 g/d) and control muffins daily, each for 4 weeks, separated by a 4-week washout. Blood and stool samples were collected per period. Serum p-cresyl sulfate (PCS), indoxyl sulfate (IS), phenylacetylglutamine (PAG), and trimethylamine N-oxide (TMAO) were quantified by LC-MS/MS, and fecal microbiota profiled by 16S rRNA gene amplicon sequencing and specific taxa of interest by qPCR. QIIME 2 sample-classifier was used to discover unique microbiota profiles due to the consumption of PHF.

Results

Intake of PHF contributed an additional 9 g/d of dietary fiber to the subjects' diet due to compliance. No significant changes from baseline were observed in serum PCS, IS, PAG, or TMAO, or for the relative quantification of Akkermansia muciniphila, Faecalibacterium prausnitzii, Bifidobacterium, or Roseburia, taxa considered health-enhancing. Dietary protein intake and IS (r = -0.5, p = 0.05) and slow transit stool form and PCS (r = 0.7, p < 0.01) were significantly correlated at baseline. PHF and control periods were not differentiated; however, using machine learning, taxa most distinguishing the microbiota composition during the PHF periods compared to usual diet alone were enriched Gemmiger, Collinsella, and depleted Lactobacillus, Ruminococcus, Coprococcus, and Mogibacteriaceae.

Conclusion

PHF supplementation did not mitigate serum levels of targeted microbial-generated uremic molecules. Given the high cellulose content, which may be resistant to fermentation, PHF may not exert sufficient effects on microbiota composition to modulate its activity at the dose consumed.

Influence of antibiotic-resistance and exudate on peroxyacetic acid tolerance in O157 and non-O157 Shiga toxin producing E. coli

Shiga toxin producing Escherichia coli (STEC) continues to cause foodborne outbreaks associated with beef and beef products despite consistent use of antimicrobial interventions. In this study, the influence of antibiotic resistance (ABR) in E. coli O157:H7 H1730, O157:H7 43,895, O121:H19 and O26:H11 on tolerance to peroxyacetic acid (PAA) was evaluated. Further, bactericidal concentrations of PAA in the presence of nutrient rich media (Tryptic Soy Broth, TSB and beef exudates) and nutrient deficient media (Sterile Deionized Water, SDW and Phosphate Buffered Saline, PBS) were evaluated for all bacterial strains. Antibiotic resistance to ampicillin (amp C), or ampicillin and streptomycin (amp P strep C) was generated in each bacterial strain through incremental exposure to the antibiotics or by plasmid transformation (n = 12 total strains). The mean bactericidal concentrations of PAA were higher (p ≤ 0.05) in nutrient rich media (205.55 ± 31.11 in beef exudate and 195.83 ± 25.00 ppm in TSB) than in nutrient deficient media (57.91 ± 11.97 ppm in SDW and 56.66 ± 9.56 ppm in PBS). Strain O157: H7 ampP strepC was the most tolerant to PAA (p ≤ 0.05). At 200 ppm in nutrient rich media and 60 ppm in nutrient deficient media, all bacterial strains declined in population to below the limit of detection. Analysis of the beef exudates indicated the presence of diverse amino acids that have been associated with acid tolerance. The results from this study indicate that beef exudates could contribute to acid tolerance and suggest that some STEC bacterial strains with certain ABR profiles might be more tolerant to PAA.

Relationships between sensory properties and metabolomic profiles of different apple cultivars

Flavor is a critical factor in apple quality. To better understand apple flavor, this study aimed to identify the relationships between sensory attributes and the chemical composition (volatiles and non-volatiles) of apples using a combined metabolomic and sensory evaluation. Sensory results showed the positive (apple, fruity, pineapple, sweetness, sourness) and negative (cucumber) flavor attributes of apples. A metabolomic analysis with statistical correlations revealed significant metabolites related to the flavor attributes of apples. Volatile esters (e.g., hexyl acetate and 2-methylbutyl acetate for apple and fruity notes) and non-volatile sugars and acids (total sugars, tartaric acid, and malic acid for balanced sweet and tart flavors) were associated with the apple flavor preferred by consumers. Some aldehydes and alcohols (e.g., (E)-2-nonenal) contributed to a negative hedonic perception (cucumber). The collected information demonstrated the roles of key chemical compounds in apple flavor quality, and may be applicable to quality control.

P15.11.A 18F-Fluciclovine PET/CT to distinguish radiation necrosis from tumour progression in brain metastases treated with stereotactic radiosurgery: results of a prospective pilot study

Background

Amino acid PET radiopharmaceutical, 18F-fluciclovine, shows increased uptake in brain tumors relative to normal tissue and may be a useful tool for detecting recurrent brain metastases. Here, we report results from a prospective pilot study evaluating the use of 18F-fluciclovine PET/CT to distinguish radiation necrosis from tumour progression among patients with brain metastases treated with stereotactic radiosurgery (SRS).

Material and Methods

The primary objective was to estimate the accuracy of 18F-fluciclovine PET/CT in distinguishing radiation necrosis from tumour progression. The trial included adults with brain metastases who underwent SRS and presented with a follow up MRI brain (with DSC MR perfusion) which was equivocal for radiation necrosis versus tumour progression. Within 30 days of equivocal MRI brain, patients underwent an 18F-fluciclovine PET/CT (Siemens mCT) acquired 5-15 min post-injection with images generated by PSF reconstruction. Quantitative metrics for each lesion were documented and lesion to normal brain SUVmean ratios were calculated. The reference standard for diagnosis of radiation necrosis vs tumour progression was clinical follow up with MRI brain every 2-4 months until multidisciplinary consensus or tissue confirmation.

Results

Of 16 patients enrolled between 7/2019-11/2020, 1 patient died prior to diagnosis, allowing 15 evaluable subjects with 20 lesions. Primary histology was NSCLC in 9 (45%) lesions, breast in 7 (35%), melanoma in 3 (15%), and endometrial in 1 (5%). The final diagnosis was radiation necrosis in 16 (80%) lesions and tumour progression in 4 (20%). SUVmax was a statistically significant predictor of tumour progression (P = 0.011), with higher SUVmax values indicative of tumour progression. The area under the ROC curve was 0.833 (95% CI: 0.590, 1.0). A cutoff of 4.3 provided a sensitivity to identify tumour progression of 1.0 (4/4) and specificity to rule out tumour progression of 0.63 (10/16). SUVmean (P = 0.018), SUVpeak (P = 0.007), and SUVpeak/normal (P = 0.002) also reached statistical significance as predictors of tumour progression, with higher SUVmax values indicative of tumour progression. SUVmax/normal (P = 0.1) and SUVmean/normal (P = 0.5) were not statistically significant. The AUC for SUVmax was not significantly higher than the AUCs for the other quantitative variables (P-values &gt; 0.2).

Conclusion

In this prospective pilot study, 18F Fluciclovine PET/CT demonstrated promising accuracy to distinguish radiation necrosis from tumour progression among patients with brain metastases previously treated with SRS. Using SUVmax, a cutpoint of 4.3 provided a sensitivity of 1.0 and specificity of 0.63. Confirmatory phase II and III studies are ongoing.

Pathway-Based Metabolomics Analysis Reveals Biosynthesis of Key Flavor Compounds in Mango

Mango is a tropical fruit with global demand as a result of its high sensory quality and nutritional attributes. Improving fruit quality at the consumer level could increase demand, but fruit quality is a complex trait requiring a deep understanding of flavor development to uncover key pathways that could become targets for improving sensory quality. Here, a pathway-based metabolomics (untargeted and targeted) approach was used to explore biosynthetic mechanisms of key flavor compounds with five core metabolic pathways (butanoate metabolism, phenylalanine biosynthesis and metabolism, terpenoid backbone biosynthesis, linoleic and linolenic acid pathway, and carbon fixation and sucrose metabolism) in three mango cultivars. The relationships between flavor precursors and flavor compounds were identified using correlation analysis. With these novel strategies, differentially regulated metabolic flux through the pathways was first elucidated, demonstrating possible mechanisms of key flavor formation and regulation in mango fruits.

Increased susceptibility to Chrysanthemum Yellows phytoplasma infection in Atcals7ko plants is accompanied by enhanced expression of carbohydrate transporters

Loss of CALS7 appears to confer increased susceptibility to phytoplasma infection in Arabidopsis, altering expression of genes involved in sugar metabolism and membrane transport. Callose deposition around sieve pores, under control of callose synthase 7 (CALS7), has been interpreted as a mechanical response to limit pathogen spread in phytoplasma-infected plants. Wild-type and Atcals7ko mutants were, therefore, employed to unveil the mode of involvement of CALS7 in the plant's response to phytoplasma infection. The fresh weights of healthy and CY-(Chrysanthemum Yellows) phytoplasma-infected Arabidopsis wild type and mutant plants indicated two superimposed effects of the absence of CALS7: a partial impairment of photo-assimilate transport and a stimulated phytoplasma proliferation as illustrated by a significantly increased phytoplasma titre in Atcal7ko mutants. Further studies solely dealt with the effects of CALS7 absence on phytoplasma growth. Phytoplasma infection affected sieve-element substructure to a larger extent in mutants than in wild-type plants, which was also true for the levels of some free carbohydrates. Moreover, infection induced a similar upregulation of gene expression of enzymes involved in sucrose cleavage (AtSUS5, AtSUS6) and transmembrane transport (AtSWEET11) in mutants and wild-type plants, but an increased gene expression of carbohydrate transmembrane transporters (AtSWEET12, AtSTP13, AtSUC3) in infected mutants only. It remains still unclear how the absence of AtCALS7 leads to gene upregulation and how an increased intercellular mobility of carbohydrates and possibly effectors contributes to a higher susceptibility. It is also unclear if modified sieve-pore structures in mutants allow a better spread of phytoplasmas giving rise to higher titre.

Mediterranean Diet Adherence in People With Parkinson's Disease Reduces Constipation Symptoms and Changes Fecal Microbiota After a 5-Week Single-Arm Pilot Study

Introduction: Non-motor symptoms of Parkinson's disease (PD) such as gastrointestinal (GI) dysfunction are common, yet little is known about how modifying dietary intake impacts PD symptoms. The aim of this study in individuals with PD was to determine whether a Mediterranean diet intervention is feasible and affects GI function, intestinal permeability and fecal microbial communities.

Methods: A single-arm, 5-week Mediterranean diet intervention study was conducted in eight people with PD. Daily and weekly questionnaires were administered to determine changes in GI symptoms. Urine and stool samples were collected at baseline and after 5 weeks to assess intestinal permeability and fecal microbial communities. Additionally, live-in partners of the participants with PD were matched as controls (n = 8) for baseline urine and stool samples.

Results: Participants with PD increased intake of Mediterranean diet based on adherence scores from baseline to week 5 (4.4 ± 0.6 vs. 11.9 ± 0.7; P < 0.01 with >10 representing good adherence), which was linked with weight loss (77.4 kg vs. 74.9 kg, P = 0.01). Constipation syndrome scores decreased after 5 weeks (2.3 ± 0.5 vs. 1.5 ± 0.3; P = 0.04). Bilophila, was higher at baseline in PD (0.6 ± 0.1% vs. 0.2 ± 0.1% P = 0.02) and slightly decreased after the diet intervention (0.5 ± 0.1%; P = 0.01). Interestingly, the proportion of Roseburia was significantly lower in PD compared to controls (0.6 ± 0.2% vs. 1.6 ± 0.3%; P = 0.02) and increased at week 5 (0.9 ± 0.2%; P < 0.01). No differences were observed for markers of intestinal permeability between the control and PD groups or post-intervention.

Conclusions: Short-term Mediterranean diet adherence is feasible in participants with PD; correlated with weight loss, improved constipation, and modified gut microbiota.

Clinical Trial Registration:ClinicalTrials.gov, identifier: NCT03851861.

Salicylic acid mediated immune response of Citrus sinensis to varying frequencies of herbivory and pathogen inoculation

BACKGROUND

Plant immunity against pathogens and pests is comprised of complex mechanisms orchestrated by signaling pathways regulated by plant hormones [Salicylic acid (SA) and Jasmonic acid (JA)]. Investigations of plant immune response to phytopathogens and phloem-feeders have revealed that SA plays a critical role in reprogramming of the activity and/or localization of transcriptional regulators via post-translational modifications. We explored the contributing effects of herbivory by a phytopathogen vector [Asian citrus psyllid, Diaphorina citri] and pathogen [Candidatus Liberibacter asiaticus (CaLas)] infection on response of sweet orange [Citrus sinensis (L.) Osbeck] using manipulative treatments designed to mimic the types of infestations/infections that citrus growers experience when cultivating citrus in the face of Huanglongbing (HLB) disease.

RESULTS

A one-time (7 days) inoculation access period with CaLas-infected vectors caused SA-associated upregulation of PR-1, stimulating defense response after a long period of infection without herbivory (270 and 360 days). In contrast, while repeated (monthly) 'pulses' of 7 day feeding injury by psyllids stimulated immunity in CaLas-infected citrus by increasing SA in leaves initially (up to 120 days), long-term (270 and 360 days) repeated herbivory caused SA to decrease coincident with upregulation of genes associated with SA metabolism (BMST and DMR6). Similarly, transcriptional responses and metabolite (SA and its analytes) accumulation in citrus leaves exposed to a continuously reproducing population of D. citri exhibited a transitory upregulation of genes associated with SA signaling at 120 days and a posterior downregulation after long-term psyllid (adults and nymphs) feeding (270 and 360 days).

CONCLUSIONS

Herbivory played an important role in regulation of SA accumulation in mature leaves of C. sinensis, whether or not those trees were coincidentally infected with CaLas. Our results indicate that prevention of feeding injury inflicted by D. citri from the tritrophic interaction may allow citrus plants to better cope with the consequences of CaLas infection, highlighting the importance of vector suppression as a component of managing this cosmopolitan disease.

Metabolomic analysis elucidates how shade conditions ameliorate the deleterious effects of greening (Huanglongbing) disease in citrus

Under tropical and subtropical environments, citrus leaves are exposed to excess sunlight, inducing photoinhibition. Huanglongbing (HLB, citrus greening), a devastating phloem-limited disease putatively caused by Candidatus Liberibacter asiaticus, exacerbates this challenge with additional photosynthetic loss and excessive starch accumulation. A combined metabolomics and physiological approach was used to elucidate whether shade alleviates the deleterious effects of HLB in field-grown citrus trees, and to understand the underlying metabolic mechanisms related to shade-induced morpho-physiological changes in citrus. Using metabolite profiling and multinomial logistic regression, we identified pivotal metabolites altered in response to shade. A core metabolic network associated with shade conditions was identified through pathway enrichment analysis and metabolite mapping. We measured physio-biochemical responses and growth and yield characteristics. With these, the relationships between metabolic network and the variables measured above were investigated. We found that moderate-shade alleviates sink limitation by preventing excessive starch accumulation and increasing foliar sucrose levels. Increased growth and fruit yield in shaded compared with non-shaded trees were associated with increased photosystem II efficiency and leaf carbon fixation pathway metabolites. Our study also shows that, in HLB-affected trees under shade, the signaling of plant hormones (auxins and cytokinins) and nitrogen supply were downregulated with reducing new shoot production likely due to diminished needs of cell damage repair and tissue regeneration under shade. Overall, our findings provide the first glimpse of the complex dynamics between cellular metabolites and leaf physiological functions in citrus HLB pathosystem under shade, and reveal the mechanistic basis of how shade ameliorates HLB disease.

Comparative Leaf Volatile Profiles of Two Contrasting Mandarin Cultivars against Candidatus Liberibacter asiaticus Infection Illustrate Huanglongbing Tolerance Mechanisms

Huanglongbing (HLB), presumably caused by Candidatus Liberibacter asiaticus (CaLas), is a devastating citrus disease worldwide. While all citrus are affected by HLB, some cultivars display greater tolerance; however, the underlying mechanisms are not fully understood. Here, volatile changes in HLB-tolerant LB8-9 Sugar Belle (SB) and HLB-sensitive Murcott mandarins after CaLas infection were comprehensively compared to determine if specific volatiles are associated with HLB responses and to discern the underlying tolerance mechanisms. These cultivars emitted qualitatively and quantitatively different volatiles in response to HLB induced by artificial graft or natural psyllid inoculation. Increasing amounts of total volatiles and de novo-synthesized new volatiles were two key responses to HLB of both cultivars. Markers potentially associated with HLB and host susceptibility were identified. Terpenoid biosynthetic pathway, green leaf volatile, and thymol metabolic pathways responsive to CaLas infection were dramatically altered. SB mandarin allows simultaneous defense and growth, contributing to its greater HLB tolerance.

Metabolomic Analysis Provides New Insight Into Tolerance of Huanglongbing in Citrus

There have been efforts to develop citrus cultivars that are tolerant of Huanglongbing (HLB), a catastrophic phloem-limited disease. Previous studies demonstrated that continuous plant growth with phloem regeneration is one of the major characteristics of HLB tolerance. In this study, the metabolic mechanisms of HLB tolerance in citrus were elucidated using a multiple pathway-targeted metabolomic approach. Comparative analysis of healthy and infected HLB-tolerant and HLB-sensitive mandarin cultivars (Citrus reticulata) revealed differentially expressed metabolic responses among different groups. Pathway enrichment analysis indicated aspartate and glutamate metabolism, purine metabolism, and biosynthesis of plant hormones were upregulated in the tolerant group, except salicylic acid signaling. Catabolic pathways linked to energy-yielding metabolism were also upregulated in the tolerant group. These metabolisms and pathways were interconnected with each other, unveiling a pivotal metabolic network associated with HLB tolerance. In the network, auxins and cytokinins, the plant hormones responsible for plant growth and phloem regeneration, were accumulated. In addition, purine metabolites serving as energy carriers and nitrogen sources of plants were increased. Only salicylic acid-related metabolites for plant defense responses were decreased in the tolerant group. Our findings may evidence the strategy of HLB-tolerant cultivars that sustain plant growth and phloem formation rather than displaying direct plant defense to overcome the disease.

Screening of Phosphodiesterase-5 Inhibitors and Their Analogs in Dietary Supplements by Liquid Chromatography-Hybrid Ion Trap-Time of Flight Mass Spectrometry

An accurate and reliable method based on ion trap–time of flight mass spectrometry (IT–TOF MS) was developed for screening phosphodiesterase-5 inhibitors, including sildenafil, vardenafil, and tadalafil, and their analogs in dietary supplements. Various parameters affecting liquid chromatographic separation and IT–TOF detection were investigated, and the optimal conditions were determined. The separation was achieved on a reversed-phase column under gradient elution using acetonitrile and water containing 0.2% acetic acid at a flow rate of 0.2 mL/min. The chromatographic eluents were directly ionized in the IT–TOF system equipped with an electrospray ion source operating in the positive ion mode. The proposed screening method was validated by assessing its linearity, precision, and accuracy. Sequential tandem MS was conducted to obtain structural information of the references, and the fragmentation mechanism of each reference was proposed for providing spectral insight for newly synthesized analogs. Structural information, including accurate masses of both parent and fragment ions, was incorporated into the MSⁿ spectral library. The developed method was successfully applied for screening adulterated dietary supplement samples.

Analysis of Nicotine Metabolites in Hair and Nails Using QuEChERS Method Followed by Liquid Chromatography-Tandem Mass Spectrometry

Many studies have analyzed nicotine metabolites in blood and urine to determine the toxicity caused by smoking, and assess exposure to cigarettes. Recently, hair and nails have been used as alternative samples for the evaluation of smoking, as not only do they reflect long-term exposure but they are also stable and easy to collect. Liquid-liquid or solid-phase extraction has mainly been used to detect nicotine metabolites in biological samples; however, these have disadvantages, such as the use of toxic organic solvents and complex pretreatments. In this study, a modified QuEChERS method was proposed for the first time to prepare samples for the detection of nicotine metabolite cotinine (COT) and trans-3′-hydroxycotinine (3-HCOT) in hair and nails. High-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) was used to analyze traces of nicotine metabolites. The established method was validated for selectivity, linearity, lower limit of quantitation, accuracy, precision and recovery. In comparison with conventional liquid-liquid extraction (LLE), the proposed method was more robust, and resulted in higher recoveries with favorable analytical sensitivity. Using this method, clinical samples from 26 Korean infants were successfully analyzed. This method is expected to be applicable in the routine analysis of nicotine metabolites for environmental and biological exposure monitoring.

Long-term, sustained feeding by Asian citrus psyllid disrupts salicylic acid homeostasis in sweet orange

BACKGROUND

Phloem-feeding insects are known to modulate the salicylic acid (SA) signaling pathway in various plant-insect interaction models. Diaphorina citri is a phloem feeding vector of the deadly phytopathogens, Candidatus Liberibacter americanus and Candidatus Liberibacter asiaticus, and the interactions of D. citri with its host that may modulate plant defenses are not well understood. The objectives of this study were to investigate the molecular mechanisms involved in transcriptional regulation of SA modification and activation of defense-associated responses in sweet orange (Citrus sinensis) exposed to various durations (7-, 14- and 150- days) of continuous feeding by D. citri.

RESULTS

We quantified expression of genes involved in SA pathway activation and subsequent modification, as well as, associated SA metabolites (SA methyl ester, 2,3-DHBA, and SA 2-O-β-D-glucoside). NPR1 and PR-1 expression was upregulated in plants exposed to continuous feeding by D. citri for 14 days. Expression of BSMT-like, MES1-like and DMR6-like oxygenase, as well as, accumulation of their respective SA metabolites (SA methyl ester, 2,3-DHBA) was significantly higher in plants exposed to continuous feeding by D. citri for 150 days than in those without D. citri infestation. Concomitantly, expression of UGT74F2-like was significantly downregulated and its metabolite, SA 2-β-D-glucoside, was highly accumulated in trees exposed to 150 d of feeding compared to control trees without D. citri.

CONCLUSIONS

D. citri herbivory differentially regulated transcription and SA-metabolite accumulation in citrus leaves, depending on duration of insect feeding. Our results suggest that prolonged and uninterrupted exposure (150 d) of citrus to D. citri feeding suppressed plant immunity and inhibited growth, which may highlight the importance of vector suppression as part of huanglongbing (HLB) management in citrus.

Evaluation of California-Grown Blood and Cara Cara Oranges Through Consumer Testing, Descriptive Analysis, and Targeted Chemical Profiling

The acceptability of Moro, Tarocco, Cara Cara, Shahani, Bream Tarocco, Boukhobza, and Sanguinelli oranges from both commercial and research orchards was tested with adult (n = 152) and child (n = 72) consumers. Qualitative focus groups were also conducted to understand consumer familiarity and thoughts about the fruit. Sensory descriptive and chemical analyses were carried out to identify drivers of liking. Overall, consumers preferred the lighter colored varieties consisting of Tarocco, Cara Cara, and Boukhobza. One cluster of adults (n = 80) showed preferences towards sweet and fruity flavors and away from sourness and citric acid. The second adult cluster (n = 72) was tolerant of the sour fruit but did not like fruit high in bitterness and flavonoid content. The largest child cluster (n = 42) showed preferences for samples higher in orange and tropical flavors (Cara Cara, Tarocco, and Boukhobza varieties). The appearance of the Cara Cara was strongly liked by the consumer population in both quantitative and qualitative settings. Hunter scale a color values strongly correlated to the higher berry/dried fruit flavors, and concentrations of naringenin. Focus group participants noted that they were relatively unfamiliar with blood oranges. Growers and producers may want to invest in the lighter colored varieties, such as Cara Cara, Tarocco, Boukhobza and Shahani, as these were liked by a majority of consumers and were low in less desirable sensory characteristics, such as bitterness and sourness. PRACTICAL APPLICATION: Through consumer tests, sensory evaluation, and chemical analyses, this research uncovered which sensory properties may drive consumer acceptance of blood and Cara Cara oranges, and informed potential production and marketing strategies for increasing their consumption. This information should benefit the citrus industry as a whole and may enhance the use of specialty oranges by the food, beverage, and food service industries.

P14.115 A Neurologist’s Foray into Gamma Knife: Lessons Learned from the first 100 cases:

BACKGROUND

Gamma Knife Radiosurgery typically involves a neurosurgeon, radiation oncologist and physicist. Neurologists performing Gamma Knife provides a potential paradigm shift.

METHODS

The first 100 Gamma Knife procedures were completed on an Elekta Perfexion or ICON system between October 2015 and August 2018. Head frames were placed by the treating neurologist who also completed the contouring and targeting. The Radiation Oncologist defined the prescription dose and verified the plan, along with the physicist.

RESULTS

Of the first 100 cases completed by the treating neurologist, 52 were females and 48 males. The average age was 61.4 years. There were 64 metastatic cases, 25 meningiomas, 8 gliomas, 2 hemangioblastoma and 1 pituitary adenoma. There were 245 individual lesions targeted. No frame related placement complications occurred. Five large metastasis were treated as a staged procedure 1 month apart. A bolus was used on 4 occasions for lesions invading the skull. Secondary to large bifrontal craniotomies, cheek posts were used on 2 occasions, and 3 posts were used in 5 cases secondary to large unilateral frontal craniotomies. Four cases were completed under general anesthesia. In one patient with a very large head, the frame would not fit and was deconstructed, placed around the neck, reconstructed with pins placed in the cheeks. 64 of the treated patients are still alive.

CONCLUSION

While unconventional, neurologists can function as a surgical surrogate to treat intracranial neoplasms with Gamma Knife. This offers unique advantages, especially in regards to continuity of care as many of these patients had been followed and will continue to follow with neurology. With the advent of the ICON frameless based system, concerns about frame placement also become less of an issue and more facile for neurologists to perform these procedures.

Effects of heat treatment of mandarin peel on flavonoid profiles and lipid accumulation in 3T3-L1 adipocytes

Citrus peel, a primary byproduct of citrus fruits, contains a variety of flavonoids. Heat treatment is a favorable food processing for solid peel to release bioactive compounds from tissues and intensify nutritional effects. In this study, we explored alterations of flavonoids by thermal treatment of mandarin peel and their effects on lipid accumulation and intracellular levels during differentiation of 3T3-L1 cells to adipocytes. The heat-treated sample showed stronger inhibition on the formation of lipid droplets than the non-treated sample, along with enhanced intracellular levels of flavonoids. Overall flavonoids, especially flavonoid aglycones showing better efficacy, were found to increase in the peel after heat-treatment. Our findings indicate thermal processing could help release flavonoids from citrus peel and convert them into aglycone forms, leading to efficient cellular uptake and suppression of lipid accumulation in 3T3-L1 cells. This study provides useful information of heat-treated citrus peel as potential dietary supplements with antiobesity-related effects.

Bioactivity-Guided Isolation and Identification of Antiadipogenic Compounds in Shiya Tea (Leaves of Adinandra nitida)

Obesity is a worldwide epidemic contributing to a higher risk of developing maladies such as type 2 diabetes, heart disease, and cancer. Shiya tea (leaves of Adinandra nitida), a traditional Chinese tea, is widely consumed due to its palatable flavor and various curative effects, such as reducing blood pressure and blood lipids, as well as anti-inflammation, etc. However, no relevant research on the antiobesity effects of Shiya tea has been reported. In particular, no health-benefiting compounds, other than flavonoids, in Shiya tea have been reported. Thus, 3T3-L1 preadipocytes have been used as a bioactivity-guided identification model to verify the inhibitory effects of Shiya tea on adipogenesis, as well as to identify antiadipogenic compounds. Four triterpenoid saponins (1-4), including one new compound (2α,3α-dihydroxyursolic acid 28- O-β-d-glucopyranosyl ester, compound 1), and a flavonoid (5) have been identified using NMR (1D and 2D NMR) and liquid chromatography (LC)-MS techniques. Compound 1, the major antiadipogenic constituent with an IC₅₀ value of 27.6 μg/mL, has been identified for the first time in Shiya tea. To understand the structure-activity relationship, three hydrolytic compounds (1s, 2s, and 5s) were obtained to provide an inhibitory effect on lipid accumulation during 3T3-L1 adipocyte differentiation. The inhibitory effect of the triterpenoid (1s) possessing no sugar group decreased significantly, while the flavonoid (5s) also without a sugar group showed increased activity. In addition, the hydroxyl group position may also play a role in inhibitory efficacy.

Relationship between Sensory Attributes and Chemical Composition of Different Mango Cultivars

The present study investigated the relationship between the chemical composition and sensory quality of different mango ( Mangifera indica L.) cultivars by multivariate statistical analysis. The results showed that the high hedonic rating of mangoes was due in part to its flavor profile such as fruity, pineapple, and coconut with sweetness. High hedonic liking and positive flavors of mangoes could be responsible for the volatile compounds including fruity esters, 1-octanol, ( E, Z)-2,6-nonadienal, and γ-octalactone with high contents of sugars. On the other hand, turpentine-like and green flavors of mangoes are attributed to the relatively low hedonic liking of mangoes, which correlated with high contents of amino acids and terpenes. These findings demonstrated that interaction between individual chemical compounds within mangoes could be responsible for the specific sensory qualities of mango cultivars and provided insight into a paradigm for the selection and development of new and more desirable mango cultivars in the future.

Comprehensive Metabolomics Analysis of Mandarins ( Citrus reticulata) as a Tool for Variety, Rootstock, and Grove Discrimination

The metabolite profile responsible for the quality of mandarin fruit is influenced by preharvest factors including genotype, rootstock, grove location, etc. In this paper, mandarin varieties were discriminated using metabolomics. Additionally, effects on metabolic profiles due to grove location and rootstock differences were also investigated. Results revealed that mandarin varieties could be differentiated using the metabolite profile, while the compositions of flavonoids have the potential for variety differentiation. With regard to fruits of the same variety, grove location might determine the overall profile of metabolites, whereas rootstock possibly affected composition of secondary metabolites. Pathway enrichment analysis demonstrated that biosynthesis pathways of terpenoids and steroids involving limonene and linalool were highly influenced by variety diversity. Moreover, the flavonoid biosynthesis pathway, involving hesperetin, naringenin, eriodictyol, and taxifolin, was indicated to have a close relationship with rootstock differentiation. This study provides useful and important information with depth for breeding and optimizing preharvest practices.

Use of UHPLC-TripleQ with synthetic standards to profile anti-inflammatory hydroxycinnamic acid amides in root barks and leaves of Lycium barbarum

Hydroxycinnamic acid amides (HCAA) are the secondary metabolites ubiquitously exist in flowering plants, formed by condensation between hydroxycinnamates and mono or polyamines. HCAA species not only serve multiple functions in plant growth and development, but also exert significant positive effects on human health. In this study, we combined organic synthesis and UPHLC-TripleQ-MS/MS specifically targeting at HCAA species. The method was fully validated with respect to specificity, linearity, intra- and inter-day precision and accuracy, limit of detection (LOD), limit of quantification (LOQ), recovery, and reproducibility. We applied this method to identify and quantify HCAAs from the root barks and leaves of Lycium barbarum. HCAA species were reported in leaves for the first time, and 10 new HCAA species were further identified in root barks in addition to the ones reported in the literature. We also examine anti-inflammatory properties of identified HCAAs species. Seven HCAA compounds had a potent NO inhibitory effect with IC₅₀ as low as 2.381 μM (trans-N-caffeoyl phenethylamine). Our developed method largely improved analytical sensitivity of HCAAs species that potentially contributes to plant metabolomics studies.

Impact of radiation therapy and extent of resection for ependymoma in young children: A population-based study

BACKGROUND

Young children with posterior fossa ependymoma (PF-EPN) have a worse prognosis than older children, and they have a unique molecular profile (PF-EPN-A subtype). Alternative treatment strategies are often used in these young patients, and their prognostic factors are less clear.

METHODS

We characterized the prognostic factors and treatment outcomes of 482 patients between ages 0 and 3 years with the diagnosis of ependymoma identified from the Surveillance, Epidemiology, and End Results registry (1973-2013).

RESULTS

Radiation therapy (RT) was delivered to 52.3% of patients, and gross total resection (GTR) was performed in 51.0% of patients. Overall survival (OS) at 10 years was 48.4% with median follow-up of 3.3 years. WHO grade was not predictive of OS. Extent of resection was significant for survival; the 10-year OS with GTR was 61.0%, and with subtotal resection (STR) and biopsy was 38.2% and 35.0%, respectively (P < 0.001). RT significantly benefitted OS for both grades II and III. The 10-year OS for grade II was 50.5% with RT and 43.4% without (P = 0.030); 10-year OS for grade III was 66.0% with RT and 40.0% without (P = 0.002). Multivariate analysis showed significantly improved OS with RT (hazard ratio [HR] 0.601, 95% CI: 0.439-0.820, P = 0.001) and GTR (HR 0.471, 95% CI: 0.328-0.677, P < 0.0001).

CONCLUSIONS

Ependymoma outcomes in patients within 0-3 years of age significantly improved with RT and GTR. Histopathologic grading of ependymoma demonstrated no prognostic significance. Given the poor OS for this population and unique genetic profile, future prospective studies with molecular-based stratification should be performed to evaluate additional prognostic factors.

Metabolic Analysis Reveals Altered Long-Chain Fatty Acid Metabolism in the Host by Huanglongbing Disease

Candidatus Liberibacter asiaticus (CLas) is the presumed causal agent of Huanglongbing, one of the most destructive diseases in citrus. However, the lipid metabolism component of host response to this pathogen has not been investigated well. Here, metabolic profiling of a variety of long-chain fatty acids and their oxidation products was first performed to elucidate altered host metabolic responses of disease. Fatty acid signals were found to decrease obviously in response to disease regardless of cultivar. Several lipid oxidation products strongly correlated with those fatty acids were also consistently reduced in the diseased group. Using a series of statistical methods and metabolic pathway mapping, we found significant markers contributing to the pathological symptoms and identified their internal relationships and metabolic network. Our findings suggest that the infection of CLas may cause the altered metabolism of long-chain fatty acids, possibly leading to manipulation of the host's defense derived from fatty acids.

Natural Dietary Products and Their Effects on Appetite Control

Natural dietary products have been thoroughly studied for their effects of antiadipogenesis to prevent and treat obesity for decades. Nevertheless, in the past few years appetite control for the treatment of obesity has attracted much attention as a new target. Homeostatic control of energy intake involves a complex system that conveys peripheral signals to the central nervous system where multiple signals are integrated and then provide feedback to regulate satiation. This perspective aims at elucidating the neuronal mechanisms of food intake and energy balance as well as providing an alternative pathway of controlling weight using natural dietary products.

Development of an improved sample preparation platform for acidic endogenous hormones in plant tissues using electromembrane extraction

Despite their importance in pivotal signaling pathways due to trace quantities and complex matrices, the analysis of plant hormones is a challenge. Here, to improve this issue, we present an electromembrane extraction technology combined with liquid chromatography-tandem mass spectrometry for determination of acidic plant hormones including jasmonic acid, abscisic acid, salicylic acid, benzoic acid, gibberellic acid and gibberellin A₄ in plant tissues. Factors influencing extraction efficiency, such as voltage, extraction time and stirring rate were optimized using a design of experiments. Analytical performance was evaluated in terms of specificity, linearity, limit of quantification, precision, accuracy, recovery and repeatability. The results showed good linearity (r² > 0.995), precision and acceptable accuracy. The limit of quantification ranged from 0.1 to 10 ng mL^-1, and the recoveries were 34.6-50.3%. The developed method was applied in citrus leaf samples, showing better clean-up efficiency, as well as higher sensitivity compared to a previous method using liquid-liquid extraction. Organic solvent consumption was minimized during the process, making it an appealing method. More noteworthy, electromembrane extraction has been scarcely applied to plant tissues, and this is the first time that major plant hormones were extracted using this technology, with high sensitivity and selectivity. Taken together, this work gives not only a novel sample preparation platform using an electric field for plant hormones, but also a good example of extracting complex plant tissues in a simple and effective way.

Randomized Clinical Trial to Evaluate the Efficacy and Safety of Combination Therapy with Short-Pulsed 1,064-nm Neodymium-Doped Yttrium Aluminium Garnet Laser and Amorolfine Nail Lacquer for Onychomycosis

Background

Onychomycosis is one of the most prevalent fungal diseases in the general population. However, treatment is of limited effectiveness and must be administered for long periods of time. Systemic antifungal agents are associated with adverse effects.

Objective

We evaluated the clinical efficacy and safety of a 1,064-nm neodymium-doped yttrium aluminium garnet (Nd:YAG) laser with amorolfine nail lacquer to treat onychomycosis.

Methods

The 128 patients were randomly divided to 2 groups: 64 in the experimental group were treated with 1,064-nm Nd:YAG laser therapy and amorolfine nail lacquer; the other 64 were in a control group treated with topical amorolfine lacquer monotherapy. The laser treatment was 4 sessions at 4-week intervals and amorolfine lacquer was applied once a week for 16 weeks. Efficacy was assessed as response rate from standardized photographs with ImagePro®Plus (Media Cybernetics, Inc., USA) analysis, microscopic examination, and subjective evaluation.

Results

At 16 weeks, the experimental group showed a significantly higher cumulative cure rate than the control group (71.88% vs. 20.31%, p<0.0001). Clinical therapeutic effects were linked to patient satisfaction. The percent of “very satisfied” or “satisfied” responses was higher in the test group than the control group (81.25% vs. 23.44%). The treatment regimen was well tolerated, with transient discomfort observed in the test group.

Conclusion

The 1,064-nm Nd:YAG laser with amorolfine nail lacquer was effective and safe for treating onychomycosis. This therapy should be considered an alternative treatment, especially for patients with contraindications to systemic antifungal agents.

An LC/MS/MS method for quantitation of chemopreventive sphingadienes in food products and biological samples

Colorectal cancer (CRC) is a leading cause of cancer mortality. Diet has a significant influence on colon cancer risk. Identifying chemopreventive agents, dietary constituents, practices and/or diet supplements that promote gut health and reduce the incidence of intestinal neoplasias and CRC could significantly impact public health. Sphingadienes (SDs) are dietary sphingolipids found in plant-based food products. SDs are cytotoxic to colon cancer cells and exhibit chemopreventive properties. The aim of the present study was to develop a sensitive and robust ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for quantifying SDs in food products and biological samples. The assay was linear over a concentration range of 80nM to 50μM and was sensitive to a detection limit of 3.3nM. Post-extraction stability was 100% at 24h. SD content in soy oils was approximately 10nM. SDs were detected transiently in the plasma of adult mice 10min after gavage delivery of a 25mg/kg bolus and declined to baseline by 1h. SD uptake in the gut was maximal in the duodenum and peaked 1h after gavage delivery. Disappearance of SDs in the lower gastrointestinal tract suggests either rapid metabolism to yet unidentified products or potentially luminal export.