Automated Capture and Analysis of Circulating Tumor Cells in Pediatric, Adolescent and Young Adult Patients with Central Nervous System Tumors

Tumors of the central nervous system (CNS) are the most common and lethal childhood malignancy. Detection of residual disease and longitudinal monitoring of treatment response in patients are challenging and rely on serial imaging. This current standard of care fails to detect microscopic disease or provide molecular characteristics of residual tumors. As such, there is dire need for minimally invasive liquid biopsy techniques. We have previously shown the high specificity of using cell surface vimentin (CSV) to identify circulating tumor cells (CTCs) from patients bearing various types of cancers. Here, we describe the first report of CTCs captured from peripheral blood samples in 58 pediatric CNS tumor patients. In this study, we used a CSV-coated cell capture chip, the Abnova CytoQuest automated CTC isolation system, to boost the CTC capture from pediatric patients with CNS tumors. We successfully isolated CTCs in six glioma patients using immunostaining of histone H3 lysine27-to-methionine (H3K27M) mutations which are highly expressed by this tumor. We show that CSV is a viable marker for CNS CTC isolation and that this is a feasible method for detecting microscopic disease. Larger-scale studies focusing on CTCs in pediatric CNS tumors to explore their diagnostic and prognostic value are warranted.

Impact of Biomarker-Matched Therapies on Outcomes in Patients with Sarcoma Enrolled in Early-Phase Clinical Trials (SAMBA 101)

PURPOSE

Developing new therapeutics for any of the more than 100 sarcoma subtypes presents a challenge. After progression from standard therapies, patients with sarcoma may be referred for enrollment in early-phase trials. This study aimed to investigate whether enrollment in biomarker-matched early-phase clinical trials leads to better outcomes for patients with advanced sarcoma.

EXPERIMENTAL DESIGN

In this retrospective analysis, investigational treatment characteristics and longitudinal survival outcomes were analyzed in patients with biopsy-confirmed sarcoma enrolled in early-phase trials at MD Anderson Cancer Center from May 2006 to July 2021.

RESULTS

Five hundred eighty-seven patients were included [405 soft tissue, 122 bone, 60 gastrointestinal stromal tumor (GIST); median of three prior lines of therapy]. Most common subtypes were leiomyosarcoma (17.2%), liposarcoma (14.0%), and GIST (10.2%). Molecular testing was available for 511 patients (87.1%); 221 patients (37.6%) were treated in matched trials. Overall response rate was 13.1% matched compared with 4.9% in unmatched (P < 0.001); the clinical benefit rate at 6 months was 43.9% vs. 19.9% (P < 0.001). Progression-free survival was longer for patients in matched trials (median, 5.5 vs. 2.4 months; P < 0.001), and overall survival was also superior for patients in matched trials (median, 21.5 vs. 12.3 months; P < 0.001). The benefit of enrollment in matched trials was maintained when patients with GIST were excluded from the analysis.

CONCLUSIONS

Enrollment in biomarker-matched early-phase trials is associated with improved outcomes in heavily pretreated patients with metastatic sarcoma. Molecular testing of tumors from patients with advanced sarcoma and enrollment in matched trials is a reasonable therapeutic strategy.

Trastuzumab Deruxtecan, Antibody-Drug Conjugate Targeting HER2, Is Effective in Pediatric Malignancies: A Report by the Pediatric Preclinical Testing Consortium

HER2 is expressed in many pediatric solid tumors and is a target for innovative immune therapies including CAR-T cells and antibody-drug conjugates (ADC). We evaluated the preclinical efficacy of trastuzumab deruxtecan (T-DXd, DS-8201a), a humanized monoclonal HER2-targeting antibody conjugated to a topoisomerase 1 inhibitor, DXd, in patient- and cell line-derived xenograft (PDX/CDX) models. HER2 mRNA expression was determined using RNA-seq and protein expression via IHC across multiple pediatric tumor PDX models. Osteosarcoma (OS), malignant rhabdoid tumor (MRT), and Wilms tumor (WT) models with varying HER2 expression were tested using 10 mice per group. Additional histologies such as Ewing sarcoma (EWS), rhabdomyosarcoma (RMS), neuroblastoma (NB), and brain tumors were evaluated using single mouse testing (SMT) experiments. T-DXd or vehicle control was administered intravenously to mice harboring established flank tumors at a dose of 5 mg/kg on day 1. Event-free survival (EFS) and objective response were compared between treatment and control groups. HER2 mRNA expression was observed across histologies, with the highest expression in WT (median = 22 FPKM), followed by MRT, OS, and EWS. The relationship between HER2 protein and mRNA expression was inconsistent. T-DXd significantly prolonged EFS in 6/7 OS, 2/2 MRT, and 3/3 WT PDX models. Complete response (CR) or maintained CR (MCR) were observed for 4/5 WT and MRT models, whereas stable disease was the best response among OS models. SMT experiments also demonstrated activity across multiple solid tumors. Clinical trials assessing the efficacy of a HER2-directed ADC in pediatric patients with HER2-expressing tumors should be considered.

Prognostic Value of Cell-Surface Vimentin-Positive CTCs in Pediatric Sarcomas

BACKGROUND

Despite advances in care, the 5 year overall survival for patients with relapsed and or metastatic sarcoma remains as low as < 35%. Currently, there are no biomarkers available to assess disease status in patients with sarcomas and as such, disease surveillance remains reliant on serial imaging which increases the risk of secondary malignancies and heightens patient anxiety.

METHODS

Here, for the first time reported in the literature, we have enumerated the cell surface vimentin (CSV+) CTCs in the blood of 92 sarcoma pediatric and adolescent and young adult (AYA) patients as a possible marker of disease.

RESULTS

We constructed a ROC with an AUC of 0.831 resulting in a sensitivity of 85.3% and a specificity of 75%. Additionally, patients who were deemed to be CSV+ CTC positive were found to have a worse overall survival compared to those who were CSV+ CTC negative. We additionally found the use of available molecular testing increased the accuracy of our diagnostic and prognostic tests.

CONCLUSIONS

Our findings indicate that CSV+ CTCs have prognostic value and can possibly serve as a measure of disease burden.

Diagnosis, grading and management of toxicities from immunotherapies in children, adolescents and young adults with cancer

Cancer immunotherapies are associated with remarkable therapeutic response rates but also with unique and severe toxicities, which potentially result in rapid deterioration in health. The number of clinical applications for novel immune effector-cell therapies, including chimeric antigen receptor (CAR)-expressing cells, and other immunotherapies, such as immune-checkpoint inhibitors, is increasing. In this Consensus Statement, members of the Pediatric Acute Lung Injury and Sepsis Investigators (PALISI) Network Hematopoietic Cell Transplantation-Cancer Immunotherapy (HCT-CI) Subgroup, Paediatric Diseases Working Party (PDWP) of the European Society of Blood and Marrow Transplantation (EBMT), Supportive Care Committee of the Pediatric Transplantation and Cellular Therapy Consortium (PTCTC) and MD Anderson Cancer Center CAR T Cell Therapy-Associated Toxicity (CARTOX) Program collaborated to provide updated comprehensive recommendations for the care of children, adolescents and young adults receiving cancer immunotherapies. With these recommendations, we address emerging toxicity mitigation strategies, we advocate for the characterization of baseline organ function according to age and discipline-specific criteria, we recommend early critical care assessment when indicated, with consideration of reversibility of underlying pathology (instead of organ failure scores) to guide critical care interventions, and we call for researchers, regulatory agencies and sponsors to support and facilitate early inclusion of young patients with cancer in well-designed clinical trials.

Case Discussion and Literature Review: Cancer Immunotherapy, Severe Immune-Related Adverse Events, Multi-Inflammatory Syndrome, and Severe Acute Respiratory Syndrome Coronavirus 2

Pediatric, adolescent and young adult (AYA) patients receiving novel cancer immunotherapies may develop associated toxicities with overlapping signs and symptoms that are not always easily distinguished from severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection/clinical sequelae. We describe 2 diagnostically challenging cases of SARS-CoV-2 and Multi-Inflammatory Syndrome-Adult (MIS-A), in patients with a history of acute lymphoblastic leukemia following cellular therapy administration and review evolving characterization of both the natural course of SARS-CoV-2 infection and toxicities experienced in younger cancer immunotherapy patients. Vigilant monitoring for unique presentations and epidemiologic surveillance to promptly detect changes in incidence of either condition may be warranted.

ABBV-085, Antibody-Drug Conjugate Targeting LRRC15, Is Effective in Osteosarcoma: A Report by the Pediatric Preclinical Testing Consortium

Membrane protein leucine-rich repeat containing 15 (LRRC15) is known to be expressed in several solid tumors including osteosarcoma. ABBV-085, an antibody-drug conjugate against LRRC15, conjugated to monomethyl auristatin E (MMAE), was studied in osteosarcoma patient-derived xenografts (PDXs) by the Pediatric Preclinical Testing Consortium (PPTC). LRRC15 expression data were obtained from PPTC RNA-sequencing data for the PDX models. The TARGET database was mined for LRRC15 expression in human osteosarcoma. Protein expression was confirmed via IHC in three PDX models. Seven osteosarcoma PDX models (OS1, OS9, OS33, OS34, OS42, OS55, and OS60) with varying LRRC15 gene expression were studied. ABBV-085 was administered at 3 mg/kg (OS33), 6 mg/kg (all seven PDXs), and 12 mg/kg (OS60) weekly for 4 consecutive weeks via intraperitoneal injection. Control cohorts included vehicle and an isotype MMAE-linked antibody. Tumor volumes and responses were reported using PPTC statistical analysis. OS1, OS33, OS42, OS55, and OS60 had high LRRC15 expression while OS9 and OS34 had low LRRC15 expression. ABBV-085 inhibited tumor growth in six of seven PDX models as compared with vehicle control and significantly improved event-free survival in five of seven models as compared with isotype controls. Two models showed maintained complete responses while all others showed progressive disease. Response correlated with LRRC15 expression. ABBV-085's antitumor activity against osteosarcoma PDX suggests LRRC15 may be a rational target for pursuing clinical trials in patients with this disease.

Association of T and N Categories of the American Joint Commission on Cancer, 8th Edition, With Metastasis and Survival in Patients With Orbital Sarcoma

Importance

No previous studies to date have validated the American Joint Committee on Cancer (AJCC) 8th edition of the TNM classification for orbital sarcoma.

Objectives

To determine the prognostic performance of the most recent TNM classification for orbital sarcoma and to identify other prognostic factors for local recurrence, lymph node metastasis, distant metastasis, and death due to disease.

Design, Setting, and Participants

This single-center retrospective cohort study included 73 consecutive patients treated for orbital sarcoma from March 1, 2003, through June 30, 2018. Data were analyzed from November 1 to December 31, 2018.

Main Outcomes and Measures

T and N categories at presentation and disease-related outcomes, including local recurrence, lymph node metastasis, distant metastasis (DM), and death due to disease (DD).

Results

The 73 participants included 43 men (59%), and the median age was 21 (range, 0-77) years. The common histologic types were rhabdomyosarcoma (RMS) (35 [48%]), solitary fibrous tumor/hemangiopericytoma (10 [14%]), and Ewing sarcoma (8 [11%]). The most common TNM designations were T2 N0 M0 (26 [36%]) and T4 N0 M0 (24 [33%]). T category was associated with the risk of all disease-related outcomes, including local recurrence (hazard ratio [HR] for T2 vs T4, 0.22 [95% CI, 0.06-0.81]; HR for T3 vs T4, 0.59 [95% CI, 0.13-2.65]; P = .03), lymph node metastasis by the last follow-up (T1, 1 [14%]; T2, 0; T3, 0; T4, 12 [35%]; P = .001), DM (HR for T2 vs T4, 0.29 [95% CI, 0.08-1.07]; P = .04), and DD (HR of T2 vs T4, 0.16 [95% CI, 0.04-0.73]; HR of T3 vs T4, 0.30 [95% CI, 0.04-2.34]; P = .02). Higher risk of DM and higher risk of DD were associated with disease category of at least T3 (HR for DM, 3.24 [95% CI, 0.89-11.72; P = .06]; HR for DD, 6.32 [95% CI, 1.43-27.95; P = .005]), N1 disease (HR for DM, 13.33 [95% CI, 4.07-43.65; P < .001]; HR for DD, 7.07 [95% CI, 2.45-20.44; P < .001]), tumor size larger than 3 cm (HR for DM, 2.72 [95% CI, 0.92-8.05; P = .06]; HR for DD, 5.79 [95% CI, 1.85-18.14; P < .001]), and age of patient with RMS younger than 1 year or 10 years or older (HR for DM, 6.85 [95% CI, 0.83-56.53; P = .04]; HR for DD, 7.03 [95% CI, 0.85-57.83; P = .04]). Higher risk of local recurrence was associated with disease category of at least T3 (HR for<T3 vs≥T3, 0.20 [95% CI, 0.06-0.71]; P < .01) and tumor size greater than 3 cm (HR for ≤3 cm vs >3 cm, 0.27 [95% CI, 0.09-0.77]; P = .009). Higher risk of lymph node metastasis was associated with disease category of at least T3 (odds ratio [OR], 13.33 [95% CI, 1.77-602.30]; P = .004), alveolar RMS (OR, 9.98 [95% CI, 2.13-51.55]; P = .001), and age of patient with RMS younger than 1 year or 10 years or older (OR, 9.20 [95% CI, 1.01-458.29] P = .03).

Conclusions and Relevance

In patients with orbital sarcoma, T and N categories at presentation (defined by the AJCC 8th edition classification) correlate with metastasis and survival. These findings appear to support consideration of strict surveillance testing for regional nodal and systemic metastases in patients with orbital sarcoma with disease category of at least T3 and/or N1 disease.

Abstract 4396: A bioinformatics approach for cancer immunotherapeutic target identification by evaluating surfaceome gene and protein expression (CITIESGAPE) in tumor and pan-normal tissues

Targeted therapeutic strategies and some immunotherapies for cancer including but not limited to therapeutic antibodies, antibody-drug conjugates (ADCs) and CAR-T cells therapy demand precisely targeting cell-surface proteins that are distinctively expressed by cancer cells. We developed a robust analytical tool for cancer immunotherapeutic target identification by evaluating surfaceome gene and protein expression (CITIESGAPE) that are uniquely overrepresented by the tumor in contrast to pan-normal tissues. The first step was to run differential expression testing on RNA-seq transcriptome of cancer (for example, data from TARGET and TCGA) against each normal tissue (31 tissues from GTEx_v8), from which candidate genes were defined as those are higher expressed in tumor than all normal tissues (minimum LogFC &gt; 1 and maximum q &lt; 0.05). We then validated the protein expression level of candidate genes through the Human Protein Atlas (HPA) and ProteomicsDB (The latter includes mass spectrometry-based label-free proteomic data of some tumor cells and 39 normal tissues). The final and crucial step was to run surfaceome protein predicting using the COMPARTMENTS database, the HPA database and the Membranome database (v2.0), depending on an optimized confidence score. We have applied this analytical pipeline to search surfaceome proteins that are unique to Osteosarcoma, a common primary malignant bone tumor in children and young adults, and obtained 57 candidates that are potential immunotherapeutic targets. To date, eight of the top confident candidates have been further validated in clinical samples, patient-derived cell lines and xenograft models. We believe this robust analytical tool could be adaptable to other types/subtypes of cancer in searching of candidate surfaceome proteins for targeted therapy and immunotherapy, as well as precision medicine and personalized therapy.

Citation Format: Xiangjun Tian, Jing Wang, Yifei Wang, Zhongting Zhang, Michael Roth, Jonathan B. Gill, Richard Gorlick. A bioinformatics approach for cancer immunotherapeutic target identification by evaluating surfaceome gene and protein expression (CITIESGAPE) in tumor and pan-normal tissues [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4396.

CRS free T cell therapy: T cell membrane anchored and tumor targeted IL12 (ATTIL12)-T cell therapy eliminates large tumors, overcomes heterogeneity, and avoids adverse effects

Adoptive transfer of genetic engineered T cells becomes an effective approach in treating hematologic malignancies, but shows poor responses against solid tumors due to multifactorial reasons. Interleukin-12 exhibits robust T cell activating and anti-tumor efficacy. However, its clinical application was impeded due to the lethal adverse effects. We demonstrated previously that tumor targeted IL-12 (ttIL12) gene therapy avoids the toxicity of wildtype IL12 and effectively eliminate tumor metastasis. In this study, we developed a second generation of ttIL12— membrane-anchored ttIL-12 (attIL12)—to modify naive T cells, CD19CAR-T cells and OT1 T cells. This attIL12-modified T cells silent the toxicity of both IL12 and CAR-T cells associated cytokine release syndrome (CRS). Surprisingly, this ATTIL12-T cell therapy is able to eliminate multiple types of tumors with either homo- or hetero-generous environment or large size. We are in full speed to prepare a phase I clinical trial.

Abstract 3655: Mapping the osteogenic lineage and identification of the cell of origin of osteosarcoma through high-dimensional analysis

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and young adults. Neo-adjuvant chemotherapy combined with wide resection increased the 5-year survival rate to 60%-70%. However, treatment and outcome of OS have not changed in several decades. OS is histologically defined by the presence of malignant osteoid, suggesting it could be derived from anywhere in the osteogenic lineage between mesenchymal stem cells (MSC) and mature osteoblasts, but the cell of origin of OS is still undefined. Tracing the cells from which most cancers formed are characterized by its multipotent and/or unipotent stem cell nature. Studies on the cellular origin of tumors from phenotypic lineage-tracking and its derived progeny can reveal tissue-specific tumor-initiating cells. Investigating cell of origin of OS and osteogenic differentiation using developmentally relevant model using MSC to OB differentiation is promising. Here we developed a high-dimensional analytic pipeline using single-cell mass cytometry (CyTOF) and RNA sequencing to discover the unrecognized progenitor-osteoblast populations in the osteogenic lineage. For the data analysis, the population clustering using Flowsom and ConsensusClusterPlus on arcsinh transformed FCS data combined with t-SNE plot visualization shows that combination of CD49f, CD95, CD56, CD117 expression enables the identification and future isolation of the progenitor populations. Also, when comparing OS with the populations from MSC to OB, there are progenitor -osteoblast / mature osteoblast-like populations in tumor cells, but no MSC-like component is found. The expression level of CD56 and CD117 are significantly higher in OS compare to MSC and OB, which warrants future investigation of new therapeutic strategy. Isolation of the progenitor-osteoblast cells, gene expression comparison between OS and these progenitors, validation of their differentiation potential and tumor-initiating capacity is still underway. In this study, we developed a CyTOF based pipeline to discover the progenitor populations in the osteogenic lineage. By comparison of the OS and these progenitor cells, we may be able to unveil the cell of origin and new targeted treatment strategy of OS.

Citation Format: Yifei Wang, Sankaranarayanan Kannan, Zhongting Zhang, Wendong Zhang, Michael Roth, Jonathan B. Gill, Zhaohui Xu, Xiangjun Tian, Jing Wang, Richard Gorlick. Mapping the osteogenic lineage and identification of the cell of origin of osteosarcoma through high-dimensional analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3655.

Abstract 2866: Surfaceome profiling in osteosarcoma: Identification of the candidate immunotherapeutic target

Osteosarcoma (OS) is the most common primary malignant bone tumor in pediatric patients. Current developments in targeted therapeutic strategies show potential clinical implications in cancer treatments. However, immunotherapies such as antibody-drug conjugates (ADCs) or CAR-T cell therapy have not been sufficiently studied in OS because of the lack of tumor-specific target. In this study, we developed a multi-step RNA-seq based pipeline. First, we did RNA sequencing for our OS PDX models and 17 patient-derived OS cell lines. The results are then pooled with the RNQ-seq data from 111 OS patient via the Therapeutically Applicable Research to Generate Effective Treatments project (TARGET). All these tumor data are subsequently compared with normal tissue RNA-sequencing data from NIH Genotype-Tissue Expression (GTEx) database. The significantly differentially expressed genes (log fold change tumor versus normal &gt;1 for each tissue, p &lt; 0.01) are selected. We further filtered this gene list by cell surface protein prediction based on Gene Ontology, the TransMembrane prediction using hidden Markov models (TMHMM), and glycosylphosphatidylinositol (GPI)-anchored protein annotations. Based on the transcriptomic result, ranks of differentially expressed genes were generated. CD276, LCLAT1, and OR8B12 are the surface markers with high ranks. To validate the transcriptomic results, we prepared surface protein extraction of the PDX models and patient-derived OS cell lines. We are profiling these surface proteins by proteomic mass spectrometry. Further validation for the expression level and location of these markers are underway. Our current finding is not previously reported in OS. The results warrant further development of ADC and car-T cell therapy.

Note: This abstract was not presented at the meeting.

Citation Format: Yifei Wang, Zhongting Zhang, Sankaranarayanan Kannan, Wendong Zhang, Michael Roth, Jonathan B. Gill, Zhaohui Xu, Xiangjun Tian, Jing Wang, Richard Gorlick. Surfaceome profiling in osteosarcoma: Identification of the candidate immunotherapeutic target [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2866.

Abstract 1345: Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients

The clinical utility of blood analysis such as circulating tumor cells (CTCs) has garnered increasing interest in recent years. However very few studies were conducted in pediatric cancer patients especially in brain tumor, osteosarcoma, and leukemia patients due to the lack of an effective tool to isolate/capture CTC from these patients. For example, only three independent studies were published to investigate CTC capture from adult brain tumor patients but zero studies were conducted with pediatric brain cancer patients. Our previous studies showed the high specificity of using cell surface vimentin (CSV) to identify and capture CTCs from various types of adult tumor patients using a manual isolation method. Here we present the first automated system for capturing CTCs across different types of pediatric tumors. This automated system utilizes the Abnova CytoQuest system loaded with the CSV antibody 84-1-coated microfluidic cassette for capturing CTCs from peripheral blood samples. This automated assay was very sensitive because as few as one tumor cell can be captured out from one million normal cells. Based on our preliminary study, our success rate for non-DIPG brain tumor, ALL, and AML patients is 100%. This success provides a potential opportunity for analyzing brain tumor genetic properties using blood samples instead of the invasive tumor biopsy; likewise, this high sensitivity assay opens up clinical opportunities to use this assay for transplant and treatment decision making.

Note: This abstract was not presented at the meeting.

Citation Format: Izhar S. Batth, Wafik Zaky, Soumen Khatua, Najat C. Daw, Kris M. Mahadeo, Sajad Khazal, Aisha Albert, Wilber Huang, Diva Chen, Jonathan B. Gill, Eugenie Kleinerman, Richard Gorlick, Shulin Li. Automated capture and analysis of circulating tumor cells across different types of tumors in pediatric cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1345.

A randomized trial of the effectiveness of the neutropenic diet versus food safety guidelines on infection rate in pediatric oncology patients

BACKGROUND

The neutropenic diet (ND) is prescribed to avoid introduction of bacteria into a host's gastrointestinal tract and reduce infection. Due to a lack of evidence to support the ND, there continues to be debate among pediatric oncologists regarding its usefulness. This prospective randomized controlled trial evaluated the difference in neutropenic infection rates in pediatric oncology patients randomized to Food and Drug Administration approved food safety guidelines (FSGs) versus the ND plus FSGs during one cycle of chemotherapy.

PROCEDURE

Pediatric patients receiving cancer treatment with myelosuppressive chemotherapy were eligible. Neutropenic infection was the primary outcome and defined as (i) fever with neutropenia or (ii) hospital admission and treatment for clinical infection and neutropenia. The rate of neutropenic infection was compared with Student's t-test for independent samples. Documented infections were identified by comprehensive chart review and compared between groups using a χ² test.

RESULTS

One hundred fifty patients were randomly assigned to FSGs (n = 73) or ND + FSGs (n = 77). The most common diagnoses were acute lymphoblastic leukemia (32%) and sarcoma (32%). There was no significant difference between the groups in the percentage of patients who developed neutropenic infection: FSGs 33% versus ND + FSGs 35% (P = 0.78). Patients randomized to ND + FSGs reported that following the diet required more effort than those on FSGs alone.

CONCLUSION

The ND offers no benefit over FSGs in the prevention of infection in pediatric oncology patients undergoing myelosuppressive chemotherapy and adherence requires more effort for patients and families. Institutions caring for children with cancer should consider replacing ND guidelines with FSGs.

Management of chemotherapy-induced febrile neutropenia in pediatric oncology patients: A North American survey of pediatric hematology/oncology and pediatric infectious disease physicians

BACKGROUND

Chemotherapy-induced febrile neutropenia (FN) is traditionally managed with hospital admission for parenteral antibiotics until neutropenia resolves. Recent studies have explored risk stratification and the safety of managing "low-risk" patients as outpatients. Few studies have directly assessed pediatric provider preferences for managing FN.

PROCEDURE

We conducted a survey of practicing US and Canadian pediatric hematology/oncology (PHO) and pediatric infectious disease (PID) physicians to assess their FN management preferences using case scenarios with varying risk profiles.

RESULTS

Twenty-one percent (n = 186) of PHO and 32% (n = 123) of PID physicians completed the survey. Overall, both groups of providers agreed regarding which patients with FN could be managed outpatient. For a child with acute lymphoblastic leukemia receiving maintenance chemotherapy with an absolute neutrophil count (ANC) of 400 cells/μl, 35% (n = 66) of PHO and 49% (n = 60) of PID physicians would consider outpatient management (P = 0.02). Of those physicians selecting inpatient management, 41% (n = 49) of PHO and 52% (n = 33) of PID physicians would be willing to discharge the patient without an increase in ANC, if afebrile with a negative blood culture (P = 0.16). For a similar patient with an ANC of 100 cells/μl, only 23% (n = 35) of PHO and 42% (n = 39) of PID physicians would consider discharge without an increase in ANC (P = 0.002).

CONCLUSIONS

Despite the lack of established guidelines for low-risk pediatric FN, a significant proportion of North American physicians report willingness to modify traditional management. This reinforces the need for evidence-based low-risk criteria and outpatient management guidelines to optimize consistency of care for these patients.

Abstract 1950: Introducing c-Myc into transformed human mesenchymal stem cells and osteoblasts to recapitulate the osteosarcoma phenotype

Osteosarcoma (OS) is the most common primary malignant bone tumor in children and young adults. It remains unclear at what point in the pathway of differentiation between human mesenchymal stem cells (hMSCs) and osteoblasts (OBs), OS originates. Since high grade OS frequently demonstrates histologic variability, as well as the potential for multi-lineage differentiation, some consider the hMSC as the cell of origin in OS, whereas others believe the osteoblast to be the most likely cell of origin. Identifying the primary cell of origin is crucial in understanding the molecular pathogenesis of OS. To address the potential for hMSCs or OBs to transform into OS, we have performed insertional mutagenesis in hMSCs and OBs with defined genetic elements which have the potential to lead to tumorigenesis and whose pathways have been altered in OS patient specimens. Serial introduction of the viral constructs hTERT (T), SV40Tag (S), and H-RAS (R), led to spindle cell tumor formation in mice. However, MSC-TSR tumors did not form osteoid, whereas OB-TSR tumors showed only scant production of osteoid. Also the addition of β-catenin to MSC-TS cells failed to lead to tumor formation in mice. Based on these findings, MSC-TS and OB-TS cell lines may be ideal platforms for further analysis of the impact of the genetic transformation of hMSCs and OBs into OS. c-Myc has been shown to be overexpressed in OS cells and hence has been suggested as an oncogene. It has been also suggested as a novel target of RUNX2 through rescue from the apoptosis.

MSC-TS and OB-TS cells were transformed with a retrovirus containing human c-Myc. Drug resistant colonies were picked up 21 days after selection to obtain stably transformed cell lines. Quantitative PCR and western blots were carried out to detect both gene and protein expression patterns in transformed cell lines, respectively. Furthermore, in order to determine the expression pattern of c-Myc in OS, quantitative PCR and western blots were also performed on human osteosarcoma primary samples, xenografts and cell lines. All functional assays outlined below will be performed to determine the tumorigenic properties of transformed cell lines.

Six out of seven (86%) osteosarcoma primary samples showed a significantly greater c-Myc gene expression level compared to the positive control cell lines. Selection of stably transformed clones and comparison between cell lines and characterizations are underway. Further ongoing characterization includes: soft agar assays, in-vivo tumorigenic assays, histological examination for osteoid production and other OS specific immunohistochemical markers, proliferation, invasion and migration, and differentiation assays. It is our hope that this study will highlight the model that closely recapitulates the human osteosarcoma phenotype by forming a malignant spindle cell tumor that produces aberrant osteoid, and has the potential for multi-lineage differentiation.

Citation Format: Sajida Piperdi (Thein), Wendong Zhang, Daria Ivenitsky, Yidan Zhang, Yunjia Zhang, David S. Geller, Bang Hoang, Rui Yang, Jonathan B. Gill, Michael Roth, Richard Gorlick. Introducing c-Myc into transformed human mesenchymal stem cells and osteoblasts to recapitulate the osteosarcoma phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1950. doi:10.1158/1538-7445.AM2017-1950

Neutral metallated and meso-substituted porphyrins as antimicrobial agents against gram-positive pathogens

Staphylococcus aureus is a bacterial pathogen that causes severe infections among humans. The increasing emergence of antibiotic resistance necessitates the development of new strategies to combat the spread of disease. One approach is photodynamic inactivation using porphyrin photosensitizers, which generate superoxide and other radicals in the presence of light, causing cell death via the oxidation of proteins and lipids. In this study, we analyzed a novel library of meso-substituted and metallated porphyrins for activity against multidrug-resistant S. aureus. From a library of 251 compounds, 51 showed antimicrobial activity, in three discrete classes of activity: those that functioned only in light, those that had toxicity only in darkness, and those that displayed activity regardless of illumination. We further demonstrated the broad-spectrum activity of these compounds against a variety of pathogens, including Bacillus anthracis, Enterococcus faecalis, and Escherichia coli. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) analyses of lead compounds (XPZ-263 and XPZ-271) revealed strong activity and killing towards methicillin-resistant S. aureus (MRSA) strains. An analysis of mutation frequencies revealed low incidences of resistance to lead compounds by E. coli and MRSA. Finally, an exploration of the underlying mechanism of action suggests that these compounds do not depend solely upon light-induced radical generation for toxicity, highlighting their potential for clinical applications.

Prognostic importance of myocardial ischemia detected by ambulatory monitoring early after acute myocardial infarction

BACKGROUND

After an acute myocardial infarction, it is important to determine the risk of a subsequent coronary event. We studied the prognostic value of myocardial ischemia detected by ambulatory electrocardiographic (ECG) monitoring in patients who had recently had an acute myocardial infarction.

METHODS

Five to seven days after acute myocardial infarction, 406 patients underwent 48-hour ambulatory ECG monitoring, with submaximal exercise testing before discharge and measurement of the left ventricular ejection fraction within 28 days after infarction. Death, nonfatal myocardial infarction, and admission to the hospital because of unstable angina were the principal end points recorded during the one-year follow-up period.

RESULTS

The overall incidence of myocardial ischemia detected by ambulatory ECG monitoring was 23.4 percent. The mortality rates at one year were 11.6 percent among the patients with ischemia and 3.9 percent among those without ischemia (P = 0.009); 3.9 percent among the patients with a positive exercise test, 3.0 percent among those with a negative exercise test, and 16.4 percent among those in whom an exercise test was not performed (P < 0.001); and 3.6 percent among the patients with an ejection fraction greater than 50 percent, 3.5 percent among those with an ejection fraction between 35 and 50 percent, and 18.2 percent among those with an ejection fraction below 35 percent (P = 0.001). Using multiple logistic regression, we found that no diagnostic test performed after myocardial infarction provided additional prognostic information beyond that provided by the standard clinical variables used to predict the risk of death. When nonfatal myocardial infarction and admission to the hospital because of unstable angina were also included as outcome variables, ambulatory monitoring for ischemia was the only test that contributed significantly to the model. For the patients with ischemia detected by ambulatory monitoring, as compared with those who did not have evidence of ischemia, the odds ratio was 2.3 (95 percent confidence interval, 1.2 to 4.5) for death or nonfatal myocardial infarction (P = 0.009) and 2.8 (95 percent confidence interval, 1.6 to 4.8) for death, nonfatal myocardial infarction, or admission to the hospital because of unstable angina (P < 0.001).

CONCLUSIONS

Myocardial ischemia detected by ambulatory ECG monitoring is common early after acute myocardial infarction and provides prognostic information beyond that available from standard clinical information.

Does it matter how coronary projections are combined to assess restenosis following PTCA?

Three methods were used to combine measurements from biplane coronary views to assess restenosis following PTCA. The first 153 patients from the EMPAR trial with 118 measurable coronary stenoses were chosen for this study. The mean difference between the RAO and LAO projections used was 88 +/- 22 degrees (S.D.). There was no systematic difference in coronary dimensions between RAO and LAO views for the group. Coronary restenosis was primarily defined as loss of 50% or more of the luminal diameter gain from the procedure. The ratio of luminal loss to gain was calculated for each stenosis using (Method 1) only the lesser diameter of the two views, (Method 2) an average of the two views and, (Method 3) a calculated cross-sectional coronary lumen area. Rates of restenosis calculated in this way ranged between 36 and 44% amongst the three methods, which was not significantly different. However, individual coronary lesions might be classified as either restenosed or not by this formula, depending on which method was used to integrate the biplane coronary measurements.

Anaphylactoid reaction during an infusion of recombinant tissue-type plasminogen activator for acute myocardial infarction

Potentially life-threatening immediate hypersensitivity reactions are extremely rare among patients treated with thrombolytic agents for suspected acute myocardial infarction. A patient who developed a severe reaction during an infusion of recombinant tissue-type plasminogen activator is described. Potential causal mechanisms for the reaction could be related either to nonmedicinal additives or complement activation. Implications for treatment in the setting of acute myocardial infarction are discussed.

Management of the patient following coronary thrombolysis

Myocardial salvage can be maximized by the early institution of thrombolytic therapy and aspirin. Certain patients may benefit from the administration of intravenous heparin, beta blockers, or nitroglycerin. The routine use of percutaneous transluminal coronary angioplasty (PTCA) or calcium-channel blockers does not appear to be warranted. Recurrent myocardial ischemia should be vigorously treated with medical therapy and there may be value in cardiac catheterization, followed by PTCA or bypass surgery, depending upon the extent of myocardium at risk and the underlying coronary anatomy. Long-term morbidity and mortality may be reduced by instituting aspirin and beta blockers as well as by modifying risk factors. There is no evidence for the long-term benefit from any calcium-channel blocker. Oral anticoagulation may be warranted in those patients with a mural thrombus, congestive heart failure, or atrial fibrillation. ACE inhibitors may be of value in the presence of left ventricular dysfunction and certainly in the presence of symptomatic congestive heart failure. Antiarrhythmic therapy is generally indicated only for symptomatic or life-threatening arrhythmias. Residual myocardial ischemia should be sought by exercise testing, and those patients with poor exercise tolerance generally warrant cardiac catheterization in consideration for revascularization.

MRI detection of myocardial perfusion changes by gadolinium-DTPA infusion during dipyridamole hyperemia

To detect abnormal regional myocardial coronary flow reserve, serial spin-echo MR tomograms of four control dogs and six with a partial balloon occlusion of the left anterior descending (LAD) coronary artery were acquired before and after dipyridamole infusion and during the paramagnetic effect of a bolus plus infusion of gadolinium-DTPA. Microsphere myocardial blood flow was measured for correlation with serial regional changes in MR signal intensity. Significant difference in gadolinium-enhanced MR signal intensity existed between the hypoperfused LAD and the hyperemic left circumflex perfusion beds (46 +/- 22% vs 78 +/- 29% above baseline, respectively; P less than 0.05). The percentage changes in gadolinium-enhanced MR signal and microsphere myocardial blood flow were significantly correlated (r2 = 0.93).

Gated blood pool tomography: a technology whose time has come

Tomographic gated blood pool imaging is a natural extension of the technologies of planar gated blood pool scanning and rotating Anger camera single photon emission computed tomography (SPECT). The high photon flux, optimum 140 keV energy, and volume sampling of tomography permit reconstruction of the data in any perspective. The true three-dimensional nature of this process allows the evaluation of regional wall motion of all the cardiac chambers, unencumbered by overlapping structures. The heart can be viewed from any angle, including a long axis, short axis, apical four chamber, and a true inferior view. In addition to evaluation of regional wall motion, precise determination of chamber volumes and ejection fractions is possible. Early clinical experience has demonstrated the superiority of tomographic gated blood pool imaging over planar blood pool imaging for precisely defining subtle functional abnormalities. The enormous amount of data generated by this procedure taxes the capacity of most nuclear medicine computer systems. However, the availability of 32-bit processors and large amounts of image memory in new machines should ultimately reduce this processing time to less than ten minutes. The combination of complete visualization and quantitation suggests that a renaissance for blood pool imaging is on the horizon.

Fatty acid analogue accumulation: a marker of myocyte viability in ischemic-reperfused myocardium

A 3-methyl substituted radioiodinated long chain fatty acid analogue was evaluated as an agent for the noninvasive detection of altered fatty acid uptake in reperfused, postischemic myocardium. This iodinated fatty acid analogue, 15-(para-iodophenyl)-3-methyl pentadecanoic acid, was given intravenously at 3 hours of reperfusion following 15 minutes (Group 1, n = 5 dogs) or 60 minutes (Group 2, n = 5 dogs) of left anterior descending coronary artery occlusion. Myocardial blood flow (MBF) was measured during occlusion and reperfusion with radiolabeled microspheres administered via the left atrium. Paired ultrasonic subendocardial crystals were placed in the ischemic perfusion bed to assess regional left ventricular systolic function at baseline, during ischemia and reperfusion. Electron microscopic analysis and staining with triphenyltetrazolium chloride (TTC) was performed. Groups 1 and 2 dogs had similar (p = NS) myocardial blood flows during occlusion. TTC positive 1 g endocardial segments from Group 1 (n = 98) and Group 2 (n = 71) had 37% greater fatty acid analogue activity (0.26 +/- 0.04 vs. 0.19 +/- 0.09 percent injected dose per gram; p less than 0.05) compared with TTC negative segments from Group 2 dogs (n = 37). When fatty acid analogue activity was related to near simultaneous reperfusion blood flow, this ratio was 27% greater (p less than 0.05) in TTC positive segments (0.38 +/- 0.1) compared with TTC negative (0.30 +/- 0.16) segments, and 9% greater than normal (0.35 +/- 0.09; p less than 0.05). While ischemic regions from both Groups 1 and 2 dogs became similarly dyskinetic during occlusion (systolic shortening, -11 +/- 6 vs. -11 +/- 2%; p = NS), TTC negative segments remained akinetic (= 1 +/- 7%) at 3 hours of reperfusion while TTC positive zones had recovered partial systolic function (8 +/- 22%). Electron microscopy confirmed the presence of reversible ultrastructural changes in TTC positive regions. A 60-minute occlusion, 3-hour reperfusion model adapted for in vivo single photon emission computed tomography showed a similar excess of 123I fatty acid activity over flow when compared to perfusion (as measured with 201Tl) in the ischemic border zone of 4/4 canine myocardial infarcts. We conclude that the accumulation of this non-beta-oxidized fatty acid analogue noninvasively identifies zones of discordance between fatty acid and flow distribution that are characteristic of ischemically "stunned" but viable myocardium.

Continuous monitoring of left ventricular function by an ambulatory radionuclide detector in patients with coronary artery disease

Global left ventricular function and a modified V5 electrocardiographic (ECG) lead were continuously monitored by a radionuclide recorder in 12 normal subjects and 39 patients with coronary artery disease while the subjects were performing various daily activities. The ambulatory studies revealed that walking on a level surface caused 11 of 12 normal subjects and 18 of 32 patients to increase their left ventricular ejection fraction by greater than 6% units. A transient decrease in left ventricular ejection fraction (6 to 18%) lasting greater than or equal to 1 min was observed on 36 occasions in 16 patients with coronary artery disease; 12 episodes were accompanied by chest pain or shortness of breath and 24 were asymptomatic. Electrocardiographic ST segment depression suggestive of ischemia was recorded in 6 of the 12 symptomatic and 5 of the 24 asymptomatic episodes. In 10 of the 12 symptomatic episodes, left ventricular ejection fraction began to decrease 30 to 90 s before the onset of symptoms. These studies suggest that continuous monitoring of both left ventricular function and the ECG may permit stratification of episodes of ST depression suggesting ischemia by the degree of left ventricular dysfunction they produce.

Prognostic importance of thallium uptake by the lungs during exercise in coronary artery disease

We studied the value of thallium imaging as compared with clinical and exercise-test variables in predicting cardiac events occurring over five years in 525 consecutive patients referred for thallium-exercise testing in 1979. Follow-up was obtained on 467 patients (89 percent). There were 105 cardiac events--25 cardiac deaths, 33 myocardial infarctions, and 47 coronary bypass procedures. A Cox survival analysis identified increased thallium uptake by the lungs, a marker of left ventricular dysfunction during exercise, as the best predictor of a cardiac event (relative risk ratio = 3.5; 95 percent confidence interval, 2.2 to 5.4). The next most powerful predictors were a history of typical angina, a previous myocardial infarction, and ST-segment depression during exercise (relative risk ratios = 2.1, 1.8, and 1.7, respectively). No combination of variables made up for the loss in prognostic power when the variable of increased thallium uptake by the lungs was removed from the model. Cardiac events occurred over five years in 10 (5 percent) of 192 patients with a normal thallium scan, 41 (25 percent) of 163 patients with an abnormal thallium scan but normal thallium activity in the lungs, and 54 (67 percent) of 81 patients with increased thallium uptake by the lungs (P less than 0.0001). We conclude that increased uptake of thallium by the lungs during exercise predicts a high risk of subsequent cardiac events.

Myocardial uptake and clearance of thallium-201 in normal subjects: comparison of dipyridamole-induced hyperemia with exercise stress

Thallium-201 uptake and clearance after dipyridamole infusion may differ from that after exercise stress because the hemodynamic effects of these two interventions are different. In this study of normal volunteers, thallium kinetics after dipyridamole (n = 13) were determined from three serial image sets (early, intermediate and delayed) and from serial blood samples and compared with thallium kinetics after exercise (n = 15). Absolute myocardial thallium uptake was greater after dipyridamole compared with exercise (p less than 0.0001), although the relative myocardial distribution was similar. The myocardial clearance (%/h) of thallium was slower after dipyridamole than it was after exercise. Comparing dipyridamole and exercise, the differences in clearance were large from the early to the intermediate image (anterior, -11 +/- 17 versus 24 +/- 5, p = 0.0005; 50 degrees left anterior oblique, -7 +/- 11 versus 15 +/- 8, p = 0.004; 70 degrees left anterior oblique, 3 +/- 9 versus 21 +/- 6, p = 0.001). In contrast, the differences in clearance were small from the intermediate to the delayed image (anterior, 15 +/- 4 versus 20 +/- 2, p = 0.025; 50 degrees left anterior oblique, 15 +/- 4 versus 19 +/- 3, p = 0.13; 70 degrees left anterior oblique, 15 +/- 3 versus 18 +/- 2, p = 0.047). Thallium uptake and clearance in the liver, splanchnic region and spleen were greater after dipyridamole (p less than 0.001). Blood thallium levels were greater after dipyridamole (p less than 0.05) and cleared more slowly (p = 0.07). Thus, myocardial thallium-201 uptake and clearance after dipyridamole infusion differ from thallium kinetics after exercise. This difference is, in part, related to associated differences in extracardiac and blood kinetics. Diagnostic criteria for the detection of abnormal thallium-201 clearance must be specific for the type of intervention.

Cardiac response to daily activities and exercise in normal subjects assessed by an ambulatory ventricular function monitor

The cardiac response to a variety of daily activities was assessed in 18 healthy adult subjects (mean age 31 years, range 21 to 39) with an ambulatory ventricular function monitor (VEST), which records serial beat-to-beat radionuclide and electrocardiographic data. The VEST was positioned and calibrated using data recorded during a multigated blood pool scan. It was worn for an average of 3.0 +/- 1.1 hours, while the subjects performed the following activities: sitting quietly (baseline); standing in place; walking; climbing stairs; bicycle or treadmill exercise; eating; sitting in a room at 4 degrees C for 20 minutes; and urinating. To calculate ejection fraction (EF), relative end-diastolic counts, relative cardiac output and heart rate, the beat-to-beat data were averaged over 15 to 30 seconds. Compared with baseline, standing increased EF by 0.03 +/- 0.04 and decreased end-diastolic volume by 10.9 +/- 4.7%. Walking and climbing stairs increased EF by 0.10 +/- 0.05 and 0.18 +/- 0.09, respectively, and increased end-diastolic volume by 7.8 +/- 5.3% and 12.8 +/- 4.3% (p less than 0.001). Eating increased EF by 0.02 +/- 0.03 and decreased end-diastolic volume by 11.3 +/- 6.1% (p less than 0.001). Cold stimuli and urinating decreased EF by 0.05 +/- 0.04 and 0.03 +/- 0.04, respectively (p less than 0.001 and less than 0.05). Serial left ventricular function monitoring during graded bicycle and treadmill exercise revealed a rapid increase in EF in the early stages of exercise, with no further change in the late stages. Heart rate and systolic blood pressure increased progressively with each successive stage.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved left ventricular performance during exercise with verapamil or nifedipine in patients with chronic stable angina

To examine the effects of chronic oral therapy with verapamil, 120 mg three times a day, and nifedipine, 20 mg four times daily, on left ventricular ejection fraction and regional wall motion at rest and exercise, 10 patients with chronic stable angina pectoris underwent serial rest and exercise radionuclide angiography. Pre drug control study revealed a resting left ventricular ejection fraction (LVEF) of 0.62 +/- 0.08, falling to 0.54 +/- 0.12 at peak exercise (p less than 0.05). Wall motion score deteriorated from a resting value of 13.8 +/- 2.3 to 10.6 +/- 1.8 (p less than 0.01) with exercise. Patients were subsequently randomized to verapamil or nifedipine for 4 weeks each in an open-labeled crossover design. Rest and exercise radionuclide angiography were repeated at the end of each 4-week period. Neither verapamil nor nifedipine had a significant effect on resting LVEF (verapamil LVEF = 0.61 +/- 0.10, nifedipine LVEF = 0.64 +/- 0.02). Likewise, they had no significant effect on resting wall motion score (verapamil = 14.2 +/- 2.2, nifedipine = 14.4 +/- 1.6). Both verapamil and nifedipine significantly increased LVEF at peak exercise (verapamil = 0.63 +/- 0.09, nifedipine = 0.65 +/- 0.08, p less than 0.05 vs pre drug control) and improved peak exercise wall motion score (verapamil = 13 +/- 1.9, nifedipine = 13.8 +/- 1.6, p less than 0.05 vs pre drug control). Both drugs significantly reduced maximal ST depression at peak exercise and prolonged exercise duration. Episodes of angina and nitroglycerin use were also significantly reduced. In summary, verapamil and nifedipine improved left ventricular performance at exercise in patients with angina pectoris.

Multigated blood-pool tomography: new method for the assessment of left ventricular function

A technique for the semiautomatic calculation of left ventricular volumes from multigated blood-pool tomograms (MGBPT) was tested in a series of 12 patients undergoing contrast ventriculography within 48 hr of gated tomography. The parameters necessary for the calculation of volume were developed in a chest phantom study performed with a series of 99mTc-filled balloons representing the right and left ventricles. The images were analyzed for volume using a percentage of peak count-threshold of the left ventricular balloon. This technique resulted in a correlation of r = 0.99 of the calculated to the true phantom volumes (y = 0.87x + 27.4, p less than 0.01, s.e.e. = 7.87 ml). The patient studies were recorded at 16 frames/cardiac cycle at each of 60 angles over a 360 degree rotation. Reconstructed data were presented in an endless loop cine format producing a set of sequential "beating tomographic slices" in the transverse, apical four-chamber, short-axis, and long-axis oblique views. Measurements of end systolic volume (y = 0.79x + 30, r = 0.93, p less than 0.001, s.e.e. = 24 ml), end-diastolic volume (y = 0.63x + 60, r = 0.94, p less than 0.0001, s.e.e. = 20 ml) and ejection fraction (y = 0.88x - 0.02, r = 0.92, p less than 0.001, s.e.e. = 0.08) determined from the semiautomated volume method correlated well with those determined by left ventricular contrast angiography. A qualitative comparison of MGBPT, planar imaging, and left ventricular angiography in 12 patients revealed that the visual assessment of wall motion using the 16-frame tomographic slices had significant advantages over planar and single plane angiographic data in the identification of inferior, basal, and septal wall motion abnormalities as well as the extent of involvement by aneurysm formation. A quantitative comparison of wall motion in the long-axis oblique view of the MGBPT to the RAO 30 degree ventriculogram (y = 0.74x + 8.7, r = 0.82, p less than 0.0001, s.e.e. = 14%) confirmed the qualitative similarity of these two views. We conclude that MGBPT is promising as a method for accurately measuring left ventricular volumes and assessing regional wall motion.

Interlaboratory testing of the transferability of a candidate reference method for total cholesterol in serum

In 1975 the Centers for Disease Control, in cooperation with the American Association for Clinical Chemistry Cholesterol Reference Method Study Group, began an investigation to develop a reference method for total cholesterol. Five potential reference methods were compared with the definitive method developed by the National Bureau of Standards before the chemical method of Abell et al. (J Biol Chem 1952;195:357-66) was selected as the recommended reference method. Because acceptance of a proposed reference method depends so greatly on the method's capability for transfer to other laboratories by written specifications and instructions, a transferability testing study was designed and conducted with 14 laboratories. The study consisted of preliminary testing of readiness of equipment, reagents, and personnel followed by transferability testing with eight runs on 10 serum pools. Laboratoires that did not meet readiness specifications had higher CVs in the transferability testing. The study demonstrated that the proposed method permits laboratories to attain a CV of less than 1.5% for one laboratory and of less than 3.0% among laboratories. The mean percent bias value was less than 1.0% for six of the 14 laboratories, less than 1.5% for 12, and less than 3.0% for all 14 laboratories.

Interlaboratory testing of the transferability of a candidate reference method for total cholesterol in serum

In 1975 the Centers for Disease Control, in cooperation with the American Association for Clinical Chemistry Cholesterol Reference Method Study Group, began an investigation to develop a reference method for total cholesterol. Five potential reference methods were compared with the definitive method developed by the National Bureau of Standards before the chemical method of Abell et al. (J Biol Chem 1952;195:357-66) was selected as the recommended reference method. Because acceptance of a proposed reference method depends so greatly on the method's capability for transfer to other laboratories by written specifications and instructions, a transferability testing study was designed and conducted with 14 laboratories. The study consisted of preliminary testing of readiness of equipment, reagents, and personnel followed by transferability testing with eight runs on 10 serum pools. Laboratoires that did not meet readiness specifications had higher CVs in the transferability testing. The study demonstrated that the proposed method permits laboratories to attain a CV of less than 1.5% for one laboratory and of less than 3.0% among laboratories. The mean percent bias value was less than 1.0% for six of the 14 laboratories, less than 1.5% for 12, and less than 3.0% for all 14 laboratories.

Accuracy and comparability of long-term measurements of cholesterol

Laboratories of the Lipid Research Clinics Program (LRC) maintained the accuracy of their measurements of total cholesterol by using seven pooled serum calibrators supplied by the Centers for Disease Control (CDC). Over the 11-year life of the LRC, each calibrator was prepared in succession and a target value was assigned by the CDC reference method for cholesterol. The results of a special experiment in which six of the seven calibrators were analyzed simultaneously demonstrated that the target values were accurately assigned. Deviations of the target values from the experimental means ranged from zero to 1.7% of the original target value. The experiment revealed no evidence of drift in the bias of the reference method over the life of LRC and demonstrated the accuracy, consistency, and the comparability of the values assigned to the successive calibrator pools used by the LRC laboratories during more than eight years. It demonstrated the reliability of a reference method and the suitability of frozen serum pools for maintaining an accurate measurement base for serum cholesterol.

Accuracy and comparability of long-term measurements of cholesterol

Laboratories of the Lipid Research Clinics Program (LRC) maintained the accuracy of their measurements of total cholesterol by using seven pooled serum calibrators supplied by the Centers for Disease Control (CDC). Over the 11-year life of the LRC, each calibrator was prepared in succession and a target value was assigned by the CDC reference method for cholesterol. The results of a special experiment in which six of the seven calibrators were analyzed simultaneously demonstrated that the target values were accurately assigned. Deviations of the target values from the experimental means ranged from zero to 1.7% of the original target value. The experiment revealed no evidence of drift in the bias of the reference method over the life of LRC and demonstrated the accuracy, consistency, and the comparability of the values assigned to the successive calibrator pools used by the LRC laboratories during more than eight years. It demonstrated the reliability of a reference method and the suitability of frozen serum pools for maintaining an accurate measurement base for serum cholesterol.

Reactions in mixed non-aqueous systems containing sulfur dioxide. V. The formation of metal sulfur oxyanion compounds by the electrolytic solution of metals

The metals Ti, Zr, V, Cr, Mo, Fe, Ni and Sn dissolve electrolytically in the binary solvent system dimethyl sulfoxide-sulfur dioxide, forming metal disulfates; W forms sulfate. The metals dissolve electrolytically in other binary systems containing sulfur dioxide, forming mixtures of sulfur oxyanions. The importance of solvent parameters in metal reactivity is discussed, together with the mechanism of the reactions.