CXCL8/CXCR2 signaling mediates bone marrow fibrosis and is a therapeutic target in myelofibrosis

Proinflammatory signaling is a hallmark feature of human cancer, including in myeloproliferative neoplasms (MPNs), most notably myelofibrosis (MF). Dysregulated inflammatory signaling contributes to fibrotic progression in MF; however, the individual cytokine mediators elicited by malignant MPN cells to promote collagen-producing fibrosis and disease evolution are yet to be fully elucidated. Previously, we identified a critical role for combined constitutive JAK/STAT and aberrant NF-κB proinflammatory signaling in MF development. Using single-cell transcriptional and cytokine-secretion studies of primary cells from patients with MF and the human MPLW515L (hMPLW515L) murine model of MF, we extend our previous work and delineate the role of CXCL8/CXCR2 signaling in MF pathogenesis and bone marrow fibrosis progression. Hematopoietic stem/progenitor cells from patients with MF are enriched for a CXCL8/CXCR2 gene signature and display enhanced proliferation and fitness in response to an exogenous CXCL8 ligand in vitro. Genetic deletion of Cxcr2 in the hMPLW515L-adoptive transfer model abrogates fibrosis and extends overall survival, and pharmacologic inhibition of the CXCR1/2 pathway improves hematologic parameters, attenuates bone marrow fibrosis, and synergizes with JAK inhibitor therapy. Our mechanistic insights provide a rationale for therapeutic targeting of the CXCL8/CXCR2 pathway among patients with MF.

Why People Keep Using Knowledge Management Systems: A Causal Analysis of Continuance Behavior

This study examines the factors that cause a person to become a continuous user of a knowledge management system by examining continuance behavior. Continuance behavior is the decision to continue using a product after initial use. The data for this study were obtained using an online survey. The results were analyzed using partial least squares structural equation modeling. Six main hypotheses were developed which resulted in the evaluation of fourteen hypotheses. The results show that the technological features of a knowledge management system positively influence a user’s evaluation with limited influence from the system’s community features. The results produced a 58% coefficient of determination for knowledge management systems continuance intention and 37% for knowledge management systems continuance behavior. This investigation serves as a foundation for further research on the continuance usage of knowledge management systems. It addresses the needs of practitioners by examining which conditions they can manage to increase the purposeful use of their organizations’ knowledge management systems. The study also addresses the needs of academia by expanding the literature on continuance behavior of knowledge management systems.

Two Epidemics and a Pandemic: The Collision of Prescription Drug Misuse and Racism during COVID-19

The present study investigated the relationship between perceived racial discrimination and prescription drug misuse (PDM) among Asian, Black, and Latinx Americans during the COVID-19 crisis. U.S. racial/ethnic minorities may have been uniquely affected by two national and one global pandemic: the opioid crisis, racism, and COVID-19. Opioid death rates increased among many groups prior to the pandemic. This country witnessed an increase in racialized acts against people of color across the spectrum in the spring and summer months of the world's COVID-19 outbreak. While studies have shown a clear link between perceived racial discrimination and substance abuse outside of the global pandemic, no identified studies have done so against the backdrop of a global health pandemic. Separate hierarchical regressions revealed a significant association between perceived racial discrimination and PDM for Black Americans, Asian Americans, and Latinx individuals. Findings build on the scant literature on PDM in diverse samples and establish a relationship between perceived racial discrimination and PDM, as previously identified for other abused substances. Future post-pandemic substance misuse interventions should consider the influence of perceived racial discrimination as they help individuals recover from the aftermath of this stressful trifecta.

Progesterone inhibits cytokine/TNF-α production by porcine CL macrophages via the genomic progesterone receptor

In pigs, luteolytic sensitivity to PGF-2α (=LS) is delayed until d 13 of the estrous cycle. While the control of LS is unknown, it is temporally associated with macrophage (MAC; which secretes tumor necrosis factor [TNF]-α) infiltration into the corpora lutea (CL), and previous studies have shown that TNF-α induces LS in porcine luteal cells (LCs) in culture. This study was designed to explore the control of LS by CL macrophage (CL MAC)/TNF-α by progesterone (P4), and to examine the hypothesis that P4 acting via the genomic P4 receptor (PGR) inhibits CL MAC TNF-α and thus plays a key role in regulating LS during the pig estrous cycle. In experiment 1, the effects of LCs on CL MAC cytokine/TNF-α mRNA expression in co-culture were examined (MID cycle; ~d 7-12; no LS); results showed that LC was inhibitory to cytokine/TNF-α. In experiment 2, the effects of P4 or R5020 (PGR-agonist) on CL MAC cytokine/TNF-α mRNA expression were examined (MID cycle; ~d 7-12; no LS); results showed that both P4 and R5020 dose-dependently inhibited TNF-α. In experiment 3, CL MACs were isolated from CL at MID (~d 7-12; no LS) and LATE (~d 13-18; + LS) cycle, and TNF-α/PGR mRNA measured. Results indicated that while TNF-α mRNA was 4.2-fold greater in CL MACs from LATE vs MID cycle, PGR mRNA was 4.5-fold greater in CL MACs from MID vs LATE cycle. These data support our hypothesis and suggest that progesterone, acting via PGR, plays a critical physiological role in the control of TNF-α production by CL MACs and LS during the pig estrous cycle.

Clinical assessment of gastric emptying and sensory function utilizing gamma scintigraphy: Establishment of reference intervals for the liquid and solid components of the Nottingham test meal in healthy subjects

BACKGROUND

Current investigations of stomach function are based on small test meals that do not reliably induce symptoms and analysis techniques that rarely detect clinically relevant dysfunction. This study presents the reference intervals of the modular "Nottingham test meal" (NTM) for assessment of gastric function by gamma scintigraphy (GSc) in a representative population of healthy volunteers (HVs) stratified for age and sex.

METHODS

The NTM comprises 400 mL liquid nutrient (0.75 kcal/mL) and an optional solid component (12 solid agar-beads (0 kcal). Filling and dyspeptic sensations were documented by 100 mm visual analogue scale (VAS). Gamma scintigraphy parameters that describe early and late phase Gastric emptying (GE) were calculated from validated models.

KEY RESULTS

Gastric emptying (GE) of the liquid component was measured in 73 HVs (male 34; aged 45±20). The NTM produced normal postprandial fullness (VAS ≥30 in 41/74 subjects). Dyspeptic symptoms were rare (VAS ≥30 in 2/74 subjects). Gastric emptying half-time with the Liquid- and Solid-component -NTM was median 44 (95% reference interval 28-78) minutes and 162 (144-193) minutes, respectively. Gastric accommodation was assessed by the ratio of the liquid-NTM retained in the proximal:total stomach and by Early phase emptying assessed by gastric volume after completing the meal (GCV0). No consistent effect of anthropometric measures on GE parameters was present.

CONCLUSIONS AND INFERENCES

Reference intervals are presented for GSc measurements of gastric motor and sensory function assessed by the NTM. Studies involving patients are required to determine whether the reference interval range offers optimal diagnostic sensitivity and specificity.

Detecting expression of 5T4 in CTCs and tumor samples from NSCLC patients

The fetal oncogene 5T4 is a cell surface protein, with overexpression observed in a variety of cancers as compared to normal adult tissue. The ability to select patients with tumors that express high levels of 5T4 may enrich a clinical trial cohort with patients most likely to respond to 5T4 targeted therapy. To that end, we developed assays to measure 5T4 in both tumors and in circulating tumor cells (CTCs). We identified the presence of 5T4 in both adenocarcinoma and squamous cell carcinoma of lung, in all clinical stages and grades of disease. CTCs were identified in peripheral blood from the majority of patients with NSCLC, and 5T4 was detectable in most samples. Although 5T4 was present in both CTCs and tumors in most patients, there was no concordance between relative amount in either sample type. Clinical response rates of patients treated with the therapies directed against 5T4 in early stage clinical trials, as determined by these assays, may provide important insights into the biology of 5T4 in tumors and the mechanisms of action of 5T4-targeting therapy.

Near- and far-field investigation of dark and bright higher order resonances in square loop elements at mid-infrared wavelengths

Three different size gold square loop structures were fabricated as arrays on ZnS over a ground plane and designed to have absorptive fundamental, second order, and third order resonances at a wavelength of 10.6 µm and 60° off-normal. The angular dependent far-field spectral absorptivity was investigated over the mid-infrared for each size loop array. It was found that the second order modes were dark at normal incidence, but became excited at off-normal incidence, which is consistent with previous work for similar geometry structures. Furthermore, near-field measurements and simulations at a wavelength of 10.6 µm and 60° off-normal showed that the second order mode (quadrupolar) of the medium size loop yielded a near-field response similar in magnitude to the fundamental mode (dipolar) of the small size loop, which can be important for sensing related applications where both strong near-field enhancement and more uniform or less localized field is beneficial.

Rapid Drink Challenge in high-resolution manometry: an adjunctive test for detection of esophageal motility disorders

BACKGROUND/AIMS

The Chicago Classification for diagnosis of esophageal motility disorders by high-resolution manometry (HRM) is based on single water swallows (SWS). Emerging data suggest that a "Rapid Drink Challenge" (RDC) increases sensitivity for motility disorders. This study establishes normal values and diagnostic thresholds for RDC in clinical practice.

METHODS

Two cohort studies were performed in patients with dysphagia or reflux symptoms (development and validation sets). Healthy subjects and patient controls provided reference values. Ten SWS and two 200-mL RDC were performed. Primary diagnosis for SWS was established by the Chicago Classification. Abnormal RDC was defined by impaired esophagogastric junction (EGJ) function (elevated integrated relaxation pressure during RDC [IRP-RDC]); incomplete inhibition of contractility during and ineffective contraction after RDC. Diagnostic thresholds identified in the development set were prospectively tested in the validation set.

RESULTS

Normal values were determined in healthy (n=95; age 37.8 ± 12) and patient controls (n=44; age 46.4 ± 15). Development and validation sets included 178 (54 ± 17 years) and 226 (53 ± 16 years) patients, respectively. Integrated relaxation pressure during RDC was higher for SWS than RDC in all groups (overall P<.001), except achalasia. Rapid Drink Challenge suppressed contractility, except in achalasia type III, spasm, and hypercontractile motility disorders (P<.001). An effective after-contraction was present more often in health than disease (P<.001). Optimal diagnostic thresholds identified in the development set (IRP-RDC ≥12 mmHg achalasia, IRP-RDC ≥ 8mmHg "all cause" EGJ dysfunction), were confirmed in the validation set (both, sensitivity ~85%, specificity >95%).

CONCLUSIONS

Rapid Drink Challenge contributes clinically relevant information to routine HRM studies, especially in patients with EGJ dysfunction.

Development and validation of a large, modular test meal with liquid and solid components for assessment of gastric motor and sensory function by non-invasive imaging

BACKGROUND

Current investigations of stomach function are based on small test meals that do not reliably induce symptoms and analysis techniques that rarely detect clinically relevant dysfunction. This study introduces the large 'Nottingham Test Meal' (NTM) for assessment of gastric motor and sensory function by non-invasive imaging.

METHODS

NTM comprises 400 mL liquid nutrient (0.75 kcal/mL) and 12 solid agar-beads (0 kcal) with known breaking strength. Gastric fullness and dyspeptic sensations were documented by 100 mm visual analogue scale (VAS). Gastric emptying (GE) were measured in 24 healthy volunteers (HVs) by gastric scintigraphy (GS) and magnetic resonance imaging (MRI). The contribution of secretion to gastric volume was assessed. Parameters that describe GE were calculated from validated models. Inter-observer agreement and reproducibility were assessed.

KEY RESULTS

NTM produced moderate fullness (VAS ≥30) but no more than mild dyspeptic symptoms (VAS <30) in 24 HVs. Stable binding of meal components to labels in gastric conditions was confirmed. Distinct early and late-phase GE were detected by both modalities. Liquid GE half-time was median 49 (95% CI: 36-62) min and 68 (57-71) min for GS and MRI, respectively. Differences between GS and MRI measurements were explained by the contribution of gastric secretion. Breaking strength for agar-beads was 0.8 N/m(2) such that median 25 (8-50) % intact agar-beads and 65 (47-74) % solid material remained at 120 min on MRI and GS, respectively. Good reproducibility for liquid GE parameters was present and GE was not altered by agar-beads.

CONCLUSIONS & INFERENCES

The NTM provided an objective assessment of gastric motor and sensory function. The results were reproducible and liquid emptying was not affected by non-nutrient agar-beads. The method is potentially suitable for clinical practice.

Abstract B12: The ALK inhibitor PF-06463922 shows significant response as a single agent in ALK/MYCN driven models of neuroblastoma

ALK inhibitors such as the ALK/MET/ROS1 inhibitor crizotinib (Xalkori) have shown clinical efficacy in a number of tumour types. However, in ALK positive neuroblastoma treatment with the ALK inhibitor crizotinib has proved more difficult, highlighting the exploration of new drugs as a clinical priority. A recent report of an increased percentage of ALK positive cases in the relapsed neuroblastoma patient population, together with the increased repertoire of ALK inhibitors now available, led to the investigation of alternative ALK inhibitors with potential for use in treatment of neuroblastoma. Here we report an investigation of the activity of a next generation ALK inhibitor in a range of in vitro and pre-clinical ALK driven neuroblastoma models.

Initially PF-06463922 was tested in various neuroblastoma cell lines and a range of gain-of-function ALK neuroblastoma mutations were subsequently analyzed in more detail in engineered Ba/F3 and PC12 cell models and by in vitro kinase assays, comparing the effect of PF-06463922 in abrogating cell growth and induced pharmacodynamics markers of response with the ALK inhibitor crizotinib. These results clearly show PF-06463922 to be a superior inhibitor of ALK kinase activity inhibiting all neuroblastoma mutant ALK forms assayed. Finally, single agent oral administration of PF-06463922 lead to induction of apoptosis and a dramatic reduction in tumour volume in a genetically engineered mouse model of treatment-resistant high-risk neuroblastoma driven by aberrant expression of MYCN and activated ALK. Taken together, our results suggest that PF-06463922 represents an important potential step forward in the treatment of relapsed neuroblastoma with mutated ALK.

Statement of significance: Our results together with PK/PD analysis of PF-06463922 suggest future clinical trial investigation of ALK positive neuroblastoma

Citation Format: J. Guan, L. Danielson, D. Chand, Y. Jamin, K. Ruuth, E. Tucker, G. Umapathy, A. El Wakil, B. Witek, T. W. Johnson, T. Smeal, L. Chesler, R. H. Palmer, B. Hallberg. The ALK inhibitor PF-06463922 shows significant response as a single agent in ALK/MYCN driven models of neuroblastoma. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr B12.

Abstract 564: The expression of fetal oncogene 5T4 in CTCs obtained from NSCLC patients is discordant with the expression measured in the primary tumor

The fetal oncogene 5T4 is a cell surface protein, with over-expression observed in a variety of cancers as compared to normal adult tissue. Recent studies have shown that expression of 5T4 appears to be associated with the undifferentiated state and the epithelial-mesenchymal transition (EMT), and thus has been associated with a more invasive phenotype. We have developed assays to measure the expression of the fetal oncogene, 5T4, in both the primary tumor compartment and in the circulating tumor cell compartment. These assays were then used to investigate 5T4 expression in a small cohort of patients with NSCLC. We obtained matched primary tumor and blood samples, with the blood being obtained prior to resection of the primary tumor. The expression of 5T4 was found to be robust and measurable in both the primary and circulating tumor compartments. We observed expression of 5T4 in both adenocarcinoma and squamous cell carcinoma, in all stages and grades of tumor, with no specific correlation between expression and stage, grade or pathology. We further observed robust enumeration of CTCs in NSCLC samples. The expression of 5T4 was heterogeneous in the CTC compartment with no correlation to grade, stage or pathology. Finally, we observed no concordance between 5T4 expression in the primary tumor and the circulating tumor cell compartment. We discuss the current utility of target expression in predicting response to targeted therapy in the context of antibody based therapy, and the role that CTCs may have in the clinic.

Citation Format: Steven R. Pirie-Shepherd, Shibing Deng, Jonathon Golas, Pamela Vizcarra, Eric Tucker, Dena Marrinuci, Hans-Peter Gerber, Eric L. Powell. The expression of fetal oncogene 5T4 in CTCs obtained from NSCLC patients is discordant with the expression measured in the primary tumor. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 564. doi:10.1158/1538-7445.AM2015-564

Abstract 565: Circulating tumor cell (CTC) detection and 5T4 characterization in breast, ovarian, and lung cancer patients on active therapy

Introduction:

Monitoring CTCs from a blood draw could enable a minimally invasive, longitudinal observation of an evolving disease. Antibody drug conjugates (ADC) are a promising approach to deliver highly potent chemotherapeutics to cells expressing target proteins. An ADC that targets 5T4, an oncofetal antigen expressed on tumor initiating cells, is currently in clinical development. Patients with tumors or CTCs expressing 5T4 may benefit from this therapeutic. We sought to develop a 5T4 CTC test and to evaluate the incidence of 5T4 expressing CTCs in breast, ovarian, and lung cancer patients.

Experimental Procedures:

Blood samples from breast (n = 10), ovarian (n = 10) and NSCLC (n = 25) patients on active therapy were collected and shipped to Epic Sciences. Upon receipt, nucleated blood cells were plated onto glass microscope slides and stored at -80C. Two slides per patient were thawed and stained for cytokeratins (CK), CD45, 5T4, and DAPI. CTCs were detected using a combination of CD45 exclusion, CK and 5T4 expression, and morphology parameters. CTC enumeration and 5T4 expression were analyzed alongside pathology, staging and treatment information.

Results:

Assay Development: A novel CTC assay utilizing an antibody against 5T4 was developed. Dilutions of high, medium and low/negative 5T4 expressing cell lines were spiked into normal whole blood to assess the linearity (R2 = 0.99) of CTC detection. These cell lines as well as 5T4 high and 5T4 low patient samples were used to assess intra- and inter-assay reproducibility of% 5T4(+) CTCs. All patient and calibration control samples met acceptance criteria of ≤ 30% CV and ≤ 20% CV, respectively.

Breast Cancer: 7 of 10 patients had traditional CTCs (median: 6/mL range: 0-23/mL). 9 of 10 patients had additional subpopulations of CK(-) CTCs, apoptotic CTCs, and CTC clusters. Among non-apoptotic CTCs, 5T4 positivity was detected in 6 of 10 patient samples, with the highest% positivity seen in patients with corresponding ER(+) primary tumors.

Ovarian Cancer: 3 of 10 patients had traditional CTCs (median: 0/mL, range: 0-41/mL). Additional subpopulations were identified in the same 3 of 10 patients.

NSCLC: 14 of 25 patients had traditional CTCs (median: 1/mL, range: 0-45/mL). 20 of 25 patients had additional subpopulations.

Conclusions:

We have developed a robust, sensitive and specific assay to quantify 5T4 expression on CTCs and tested this assay on small cohorts of breast, ovarian and lung cancer patients on active therapy. CTCs expressing 5T4 were detected in a subset of patients from each indication.

Citation Format: Steven R. Pirie-Shepherd, Iman Jilani, Eric Tucker, David Valenta, Ryon Graf, Amanda Anderson, Dena Marrinucci, Puja Sapra, Eric L. Powell. Circulating tumor cell (CTC) detection and 5T4 characterization in breast, ovarian, and lung cancer patients on active therapy. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 565. doi:10.1158/1538-7445.AM2015-565

Near-field investigation of the effect of the array edge on the resonance of loop frequency selective surface elements at mid-infrared wavelengths

Mid-infrared scattering scanning near-field optical microscopy, in combination with far-field infrared spectroscopy, and simulations, was employed to investigate the effect of mutual-element coupling towards the edge of arrays of loop elements acting as frequency selective surfaces (FSSs). Two different square loop arrays on ZnS over a ground plane, resonant at 10.3 µm, were investigated. One array had elements that were closely spaced while the other array had elements with greater inter-element spacing. In addition to the dipolar resonance, we observed a new emergent resonance associated with the edge of the closely-spaced array as a finite size effect, due to the broken translational invariance.

Abstract 4819: Evaluation of PTEN status in circulating tumor cells (CTCs) and matched tumor tissue from castrate-resistant prostate cancer (CRPC) patients

Background:

PTEN loss occurs frequently in prostate cancer and may trigger progression to CRPC through activation of the PI3K/AKT pathway. A blood-based assay that determines PTEN status in CRPC patients could enable informed treatment decisions such as the use of a PI3K-targeted therapy. Here we examined the relationship between PTEN status in CTCs and matched archival and fresh tumor biopsies in 43 CRPC patients.

Methods:

Nucleated cells from CRPC patient blood were plated onto glass slides and subjected to IF staining and CTC identification by high-speed fluorescent scanners at Epic Sciences. CTCs were identified as CK+/CD45- cells with intact DAPI nuclei, and samples with ≥4 CTCs per 2 slides (74%) were then tested for PTEN by FISH. Heterozygous loss was defined as a decrease in PTEN copies (PTEN &lt; CEP10 and &lt; 2 copies) and homozygous loss as zero PTEN copies. PTEN IHC in tissue was stained using CST clone 138G6 and H-scores ≤ 200 counted as loss.

Results:

Heterozygous or homozygous loss of PTEN by FISH was observed in 16 of 43 patients (37%) by CTC analysis. In addition to loss of PTEN, changes in ploidy were frequently observed and broad heterogeneity seen both within and between patients. The PTEN status in CTCs correlated strongly with the PTEN status in metastatic tissue: All 10 patients that exhibited homozygous PTEN loss in CTCs showed concordant homozygous PTEN loss in fresh biopsies. This correlation extended to three patients that showed correlated mixed homozygous and hemizygous PTEN loss populations in CTCs and tissue. “Drift or change” in PTEN status from archival to fresh biopsies occurred in 15 patients, In 12 of these patients, PTEN status in CTCs was reflective of the status in fresh tissue. Together with PTEN evaluation, the analysis of androgen receptor expression by immunofluorescence and ERG rearrangements by FISH proved feasibility of multiplex biomarker assessment in CTCs. This analysis demonstrated heterogeneity of AR phenotypes and a positive association of ERG rearrangements and PTEN loss in CTCs, consistent with literature reports.

Conclusion:

Our results illustrate the potential for using CTCs as a non-invasive, real-time biopsy to determine a patient's current PTEN status. PTEN status will be determined using these assays in an ongoing AKT inhibitor Phase II trial.

Citation Format: Elizabeth Punnoose, Eric Tucker, Edith Szafer-Glusman, Jin Zhu, Dena Marrinucci, Jessica Louw, Florence Lee, Mikel Kitchen, Natalee Bales, Lukas Amler, Hartmut Koeppen, Premal Patel, Yibing Yan, Ruth Riisnaes, Gerhardt Attard, Johann de Bono. Evaluation of PTEN status in circulating tumor cells (CTCs) and matched tumor tissue from castrate-resistant prostate cancer (CRPC) patients. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4819. doi:10.1158/1538-7445.AM2014-4819

Array truncation effects in infrared frequency selective surfaces

A metasurface consisting of an infinite array of square loops was designed for maximal absorptivity for s-polarized light at a wavelength of 10.6 µm and 60 degrees off-normal. We investigate the effects of array truncation in finite arrays of this design using far-field FTIR spectroscopy and scattering scanning near-field optical microscopy. The far-field spectra are observed to blue-shift with decreasing array size. The near-field images show a corresponding decrease in uniformity of the local electric field amplitude and phase spatial distributions. Simulations of the far-field absorption spectra and local electric field are consistent with the measured results.

CK- and small nuclear size circulating tumor cell (CTCs) phenotypes in metastatic castration-resistant prostate cancer (mCRPC)

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Background: Circulating tumor cell (CTCs) are traditionally defined as EpCAM/CK+ cells, CD45-, and morphologically distinct. However, recent evidence suggests that other populations of CTC candidates exist including cells that are EpCAM/CK- or smaller in size than traditional CTCs. CTC positive selection techniques that isolate CTCs based on size, density, or EpCam positivity may miss subpopulations. We aimed to molecularly characterize novel CTC candidates utilizing the Epic Sciences platform, which performs no physical selection. Methods: Blood from 10 healthy volunteers (HV) and 39 patients (pts) with metastatic castration-resistant prostate cancer (mCRPC) were collected and shipped to Epic Sciences, where all nucleated cells were plated onto glass slides and subjected to immunofluorescence (IF) staining and CTC identification by fluorescent scanners and algorithms. Traditional CTCs were identified as CK+CD45- cells with intact DAPI nuclei and after pathologist review of their morphology. Candidate CK- CTC populations were identified as CK-CD45- that were morphologically malignant. Small nuclear size candidate CTCs were identified as CK+CD45- cells with diameters similar to or smaller than that of a typical white blood cells (WBCs). All candidate CTC were evaluated with prostate cancer relevant biomarkers, including androgen receptor (AR) by IF and PTEN loss and ERG rearrangements by FISH. Results: Thrity eight out of 39 pts had one or more traditional CTCs/mL and 36 out of 39 pts had one or more CK- CTCs/mL of blood. Eight out of 39 samples had more than 10 CK- CTCs/mL. Fifteen out of 39 samples had evidence of small nuclear size CTCs at varying incidences and sizes of cells. We observed PCa biomarkers including high AR expression, PTEN deletion, and ERG rearrangements in both CK- and small nuclear size CTCs. These features were not observed in over 1,000 WBCs evaluated and HV. Conclusions: Candidate CTC that are CK-CD45- and/or with a small nucleus are identified on the Epic Sciences platform in blood from mCRPC pts. Studies are ongoing to determine their clinical relevance.

Sequential monitoring and characterization of circulating tumor cells (CTCs) using the epic sciences platform in metastatic castration-resistant prostate cancer (mCRPC) patients (pts) treated with recently approved therapeutics

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Background: The enumeration and molecular characterization of circulating tumor cells (CTCs) may allow sequential evaluation of drug-induced changes and mechanisms of drug resistance that cannot be practically performed by tissue biopsies. Methods: We utilized the Epic Sciences platform to identify and characterize traditional CTCs (CK-CD45+) and other CTC subpopulations (CK-CD45- CTCs and small CTCs) in sequential samples obtained from metastatic castration-resistant prostate cancer (mCRPC) patients (pts) receiving abiraterone acetate (AA), enzalutamide (E), or cabazitaxel (C). Peripheral blood was collected pre-treatment, during treatment (at 1 to 4 weeks, to evaluate pharmacodynamics effects) and at progression. Nucleated cells were plated onto glass slides and subjected to immunofluorescence staining for CK, CD45, and AR, and CTC identification by fluorescent scanners. CTCs from a subset of patients were tested for PTEN loss and ERG rearrangements by FISH. CTCs from a second blood sample collected at the same time were captured and enumerated using CellSearch (Veridex). Fresh CRPC biopsies were available for 9 pts. Results: Initial results are available from 24 mCRPC pts (16 pts treated with AA; four with E; four with C; 17 out of 24 previously treated with docetaxel). Pre-treatment, the median CK+CD45- CTC count was 3.5 (range 0 to 98) cells/mL blood. Eleven pts had more than or equal to 5 CK+CD45- CTCs/mL pre-treatment and 5 out of 11 pts had an Epic CTC conversion to less than 5 CK+CD45- CTCs/mL with treatment. 8 out of 11 pts had a decline in CK+CD45- CTC count greater than 30%. Changes in AR expression and AR subcellular localization were observed during treatment as well as changes in count of CTC subpopulations. CellSearch count was available for 22 out of 24 pts. Twelve out of 22 had more than or equal to five CTCs/7.5mls captured using CellSearch, including 7 out of 12 with more than or equal to five CTCs/ml using Epic platform. Conclusions: Enumeration and molecular characterization of CTCs on the Epic Sciences platform during treatment is feasible and demonstrates drug-induced changes associated with changes in CTC count, AR expression and AR subcellular localization. These assays warrant further studies to validate their role as clinically useful biomarkers in mCRPC.

Measurement of esophago-gastric junction cross-sectional area and distensibility by an endolumenal functional lumen imaging probe for the diagnosis of gastro-esophageal reflux disease

BACKGROUND

Measurement of esophago-gastric junction (EGJ) cross-sectional area (CSA) and distensibility by an Endolumenal Functional Lumen Imaging Probe (EndoFLIP®) may distinguish between gastro-esophageal reflux disease (GERD) patients and healthy volunteers (HV). We aimed to assess the agreement of EndoFLIP® measurements with clinical and physiologic diagnosis of GERD.

METHODS

Twenty-one HV and 18 patients with typical GERD symptoms were studied. After gastroscopy, EGJ CSA, and distensibility were measured by EndoFLIP®. Forty-eight hour esophageal pH monitoring was then performed by a wireless system. The ability of EndoFLIP® to discriminate GERD patient and HVs was assessed. Planned secondary analysis then assessed whether EGJ CSA and distensibility were increased in individuals with pathologic acid exposure.

KEY RESULTS

Healthy volunteers were younger and had lower body mass index (BMI; both p < 0.001). Pathologic acid exposure was present in 3/21 (14%) HVs and 9/18 (50%) patients (p = 0.126). At 30 mL EndoFLIP® bag volume, EGJ CSA was higher (p = 0.058) and EGJ distensibility was lower (p = 0.020) in HVs than patients. Secondary analysis showed that EGJ measurements were similar in participants with and without pathologic acid exposure (CSA 98 mm² vs 107 mm²; p = 0.789, distensibility; p = 0.704). An inverse association between BMI and CSA (R² = 0.2758, p = 0.001) and distensibility (R² = 0.2005, p = 0.005) was present.

CONCLUSIONS & INFERENCES

Endolumenal Functional Lumen Imaging Probe is not useful for GERD diagnosis because EGJ CSA and distensibility do not distinguish between HVs and GERD patients defined by clinical presentation or pH measurement. This unexpected result may be due to an important, confounding interaction of obesity.

Near- and far-field spectroscopic imaging investigation of resonant square-loop infrared metasurfaces

Optical metamaterials have unique properties which result from geometric confinement of the optical conductivity. We developed a series of infrared metasurfaces based on an array of metallic square loop antennas. The far-field absorption spectrum can be designed with resonances across the infrared by scaling the geometric dimensions. We measure the amplitude and phase of the resonant mode as standing wave patterns within the square loops using scattering-scanning near-field optical microscopy (s-SNOM). Further, using a broad-band synchrotron-based FTIR microscope and s-SNOM at the Advanced Light Source, we are able to correlate far-field spectra to near-field modes of the metasurface as the resonance is tuned between samples. The results highlight the importance of multi-modal imaging for the design and characterization of optical metamaterials.

Abstract 4752: Preclinical development and translational research on a novel antibody-drug conjugate that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells

Antibody-drug conjugates (ADCs) represent a promising therapeutic modality for the clinical management of cancer. We sought to develop a novel ADC that targets 5T4 (TPBG), an oncofetal antigen expressed on tumor-initiating cells (TICs), which comprise the most aggressive cell population in the tumor. We optimized an anti-5T4 ADC (A1mcMMAF) by sulfydryl-based conjugation of the humanized A1 antibody to the tubulin inhibitor monomethylauristatin F (MMAF) via a maleimidocaproyl linker. A1mcMMAF exhibited potent in vivo anti-tumor activity in a variety of tumor models and induced long-term regressions for up to 100 days after the last dose. Strikingly, animals showed pathological complete response in each model. In a non-small cell lung cancer patient-derived xenograft in which 5T4 is preferentially expressed on the less differentiated tumor cells, A1mcMMAF treatment resulted in sustained tumor regressions and reduced TIC frequency. These results highlight the potential of ADCs that target the most aggressive cell populations within tumors. An optimized pharmacokinetic/pharmacodynamic (PK/PD) model of tumor growth and drug kill was used to characterize the ADC concentration response relationship in mouse. A holistic secondary parameter, tumor static concentration (TSC), was derived from model parameters to quantify efficacy and support early clinical trial design. Tumor static concentrations [80% confidence] of A1mcMMAF ranged from 1.1[0.9 -1.4] μg/ml to 11.6 [9.6 - 14.1] μg/ml across tumor models. For comparison, in the clinic T-DM1 has an average concentration of 14 μg/ml at an efficacious dose of 3.6 mg/kg Q3wk (HER+ breast cancer) (Krop et al. 2010) and Brentuximab-vedotin has an average concentration of 3.65 μg/ml at an efficacious dose of 1.8 mg/kg Q 3wk (HL/ ALCL) (Younes et al. 2010). Taken together, the preclinical data established a promising therapeutic index that supports clinical testing of A1mcMMAF. Expression analysis profiling using clinical and preclinical data indicated that lung and breast tumors demonstrated differentially high expression of 5T4 in comparison to normal tissues. An IHC assay developed in house confirmed the hypothesis that a broad range of 5T4 expression was measurable in NSCLC patient tumor samples. Additionally, we developed an assay that measures 5T4 expression on circulating tumor cells (CTCs) and used this assay to measure and characterize a broad range of 5T4 expression in CTCs obtained from the blood of NSCLC patients. We intend to deploy these co-developed immunoassays to guide A1mcMMAF clinical development.

Citation Format: Puja Sapra, Marc Damelin, Kimberly Marquette, Kenneth G. Geles, Jonathon Golas, Maureen Dougher, Bitha Narayanan, Andreas Giannakou, Kiran Khandke, Russell Dushin, Elana Ernstoff, Judy Lucas, Mauricio Leal, George Hu, Alison Betts, Nahor Haddish-Berhane, Eric Powell, Steven Pirie-Shepherd, Christopher O'Donnell, Lioudmila Tchistiakova, Hans-Peter Gerber, Dena Marrinucci, Eric Tucker. Preclinical development and translational research on a novel antibody-drug conjugate that targets 5T4, an oncofetal antigen expressed on tumor-initiating cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4752. doi:10.1158/1538-7445.AM2013-4752

Evaluation of PTEN status in circulating tumor cells (CTCs) and matched tumor tissue from patients with castrate-resistant prostate cancer (CRPC)

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Background: PTEN loss occurs frequently in prostate cancer and may trigger progression to CRPC through activation of the PI3K/AKT pathway. A blood-based assay that determines PTEN status in CRPC patients could enable informed treatment decisions such as the use of a PI3K-targeted therapy. We evaluated PTEN status in archived tissue, metastatic bone biopsies, and CTCs from CRPC patients. Here we report the results of PTEN evaluation in CTCs from 42 CRPC patients and matched tissue from 6 patients with more underway. Methods: Nucleated cells from CRPC patient blood were plated onto glass slides and subjected to IF staining and CTC identification by high-speed fluorescent scanners at Epic Sciences. CTCs were identified as CK+/CD45- cells with intact DAPI nuclei, and samples with ≥5 CTCs per 2 slides (74%) were then tested for PTEN by FISH. Partial loss was defined as a decrease in PTEN copies (PTEN < CEP10) and total loss as zero PTEN copies. PTEN IHC in tissue was stained using CST clone 138G6 and H-scores ≤ 200 counted as loss. Results: Partial or total loss of PTEN by FISH was observed in 15 of 31 patients (48%) by CTC analysis. Changes in ploidy were frequently observed and broad heterogeneity seen both within and between patients. Weighted across patients, the most frequently observed abnormal genotypes in CTCs were 2 CEP10/0 PTEN (total loss, diploid, 5.8%), 3 CEP10/0 PTEN (total loss, triploid, 4.5%), and 3 CEP10/3 PTEN (PTEN-normal, triploid, 4.2%). These genotypes were not observed in over 1,000 white blood cells evaluated evenly across 31 patients, demonstrating that cells identified as CTCs on the Epic platform show malignant features not observed in normal cells. PTEN loss was detected by IHC in 6 of 8 (75%) archived patient samples and 7 of 8 (87%) of matched bone biopsies. Where CTCs were available (6 cases), PTEN status was correctly determined as lost in 4 cases, normal in 1 case and borderline in one case. Conclusions: Our results illustrate the high percentage of PTEN loss in CRPC patients and the potential for using CTCs as a non-invasive, real-time biopsy to determine a patient’s PTEN status. PTEN status will be determined using these assays in an upcoming AKT inhibitor Phase II trial.

Multiplexed protein and gene profiling of circulating tumor cells (CTCs) in metastatic castration-resistant prostate cancer (mCRPC) using automated immunofluorescence and fluorescence in situ hybridization

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Background: Clinically, CTCs are used primarily in longitudinal monitoring of metastatic disease progression. However, the analysis of specific CTC biomarkers has the potential to optimize patient management by identifying those likely to respond to specific targeted agents. Often, mCRPC is driven by dysregulation of the androgen receptor (AR) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) oncogenic pathways such that blockade of one pathway stimulates the other. These functional deficits in the AR and PI3K/AKT pathways are associated with fusion of the TMPRSS2 and ERG genes and with loss of PTEN protein, respectively. Therefore, we sought to characterize CTCs for the simultaneous presence of both these biomarkers using immunofluorescence (IF) and fluorescence in situ hybridization (FISH). Methods: Nucleated peripheral blood cells from mCRPC patients were attached to slides and examined using CTC technology (Epic Sciences). Cytokeratin-positive/CD45-negative cells with an intact nucleus and a malignancy-consistent morphology were identified as CTCs, and their exact positions on the slides were recorded. The slides were then subjected to multiplex Quantum Dot IF and FISH procedures with anti-AR, -ERG, and -PTEN antibodies and 5’ERG, 3’ERG, PTEN, and Cen10 probes, respectively, on an automated slide-staining platform (Ventana Medical Systems, Inc.). The IF and FISH signals were visualized by spectral imaging (Ventana). Results: The automated IF/FISH staining procedure facilitated multiplex characterization of individual CTCs from patient samples for the protein biomarker targets AR, ERG, and PTEN and the genomic biomarker targets 5’ERG, 3’ERG, PTEN, and Cen10. Conclusions: This method for high-sensitivity, multiplex molecular characterization of critical CTC biomarkers in mCRPC patients might aid oncologists in identifying and stratifying those patients likely to respond to combination therapy with targeted PI3K/AKT inhibitors and anti-androgens/Cyp17 inhibitors. Patient trials examining the clinical utility of this assay in mCRPC are currently underway.

Rumination variations: aetiology and classification of abnormal behavioural responses to digestive symptoms based on high-resolution manometry studies

BACKGROUND

Rumination is the voluntary, albeit subconscious return of gastric contents to the mouth. Currently, rumination syndrome and repetitive belching disorders are considered separate diagnoses, as defined by Rome III criteria and high-resolution oesophageal manometry (HRM).

AIM

To test the hypothesis that these conditions represent a common behavioural response to aversive digestive stimuli and that successful treatment can be directed at both the stimulus and the response.

METHODS

Case-note review of consecutive patients with a final diagnosis of behavioural digestive disorders between August 2009 and October 2011.

RESULTS

Thirty-five of 46 (76%) patients exhibited 'classical' rumination with abdomino-gastric strain (R-waves) driving gastric contents across the lower oesophageal sphincter; 5 (11%) had 'reflux-related' rumination with R-waves seen during gastro-oesophageal common cavity (reflux) events and 6 had (13%) supra-gastric belching. All received at least one biofeedback session at the time of diagnosis with a good response reported by 20/46 (43%) of the patients, which included 3 with supra-gastric belching. Additionally, rumination ceased in cases in which definitive treatment relieved the symptoms that triggered abnormal behaviour (e.g. fundoplication in 'reflux-rumination').

CONCLUSIONS

Rumination and many of its variations, excluding only some cases of supra-gastric belching, are associated with abdomino-gastric strain, a generic abnormal behavioural response to a variety of aversive digestive stimuli. All types of rumination can respond to biofeedback. High-resolution oesophageal manometry identifies subgroups with distinct mechanisms of disease that respond to specific management targeted at the symptoms that trigger the abnormal behaviour.

Remapping worker citizenship in contemporary occupational health and safety regimes

The article draws on the rapidly growing field of citizenship studies to map and explore the dynamics of contemporary occupational health and safety (OHS) regulation. Using two key dimensions of OHS regulation (protection and participation), the author constructs four ideal types of worker citizenship (market, public, private industrial, and public industrial citizens). Historically, workers have been written into OHS regulatory regimes in each of these ways. Most recently lawmakers have created a new species of OHS regimes, best described as mandated partial self-regulation. Its distinguishing characteristic is its flexibility, such that worker citizenship can take on any of the forms previously described, often without changing the statutory framework. Using Ontario as an example, the study finds that in the late 20th century, workers made significant strides toward public industrial citizenship and, surprisingly, even under a neoconservative government, workers successfully defended their participatory rights and saw their right to protection modestly strengthened through increased enforcement. The conditions under which this regime operates, however, constantly threaten to undermine the efficacy of worker participation rights and to weaken the enforcement effort. Some suggestions are made about using a citizenship discourse to revitalize the worker OHS movement and strengthen OHS rights.

Diverging Trends in Worker Health and Safety Protection and Participation in Canada, 1985-2000

Despite the comprehensiveness of neo-liberal restructuring in Canada, it has not proceeded uniformly in its timing or outcomes across regulatory fields and political jurisdictions. The example of occupational health and safety (OHS) regulation is instructive. This article compares recent OHS developments in five Canadian jurisdictions, Alberta, British Columbia, Nova Scotia, Ontario and the Federal jurisdiction. It finds that despite the adoption of a common model by all jurisdictions, there has recently been considerable divergence in the way that the elements of worker participation and protection have been combined. Modified power resource theory is used to explain a portion of this divergence.

Prognostic markers in node-negative breast cancer: A prospective study

BACKGROUND

Despite years of research, it is still unclear which women with node-negative (N-) breast cancer will need adjuvant chemotherapy and which women are being treated unnecessarily. Our goal was to determine which factors best predicted disease free survival (DFS) or cancer-specific overall survival (OS) and, therefore, select the correct patients for treatment. A total of 11 parameters were measured: estrogen receptor (ER), progesterone receptor (PR), age, race, ploidy status, %G0/G1 (% non-DNA synthesis), %S (% S-phase), cathepsin D status, size, stage, and histologic grade.

RESULTS

In this prospective study, we followed 556 N- patients diagnosed between 1991 and 1996. The tumors were 56% ER+, 51% PR+, 30% diploid, with a mean %S of 8.9%. The level of cathepsin D ranged from 0.50 to 155 pmol/mg of protein with a mean of 42.9 pmol/mg of protein. There were 87 recurrences (16%) and 72 cancer deaths (13%), with a median follow-up of 7.8 years. Ploidy status (p = 0.01), S-phase activity (p = 0.003), G1 phase activity (p = 0.02) and age (p = 0.01) were able to significantly predict DFS in a univariate manner. All of the measurable factors were significant or borderline significant in predicting OS in a univariate manner except for age, race, and ER status. In multivariate analysis with S-phase included, it was the only remaining factor in DFS and OS; with S-phase excluded, age and ploidy status remained as factors for DFS in stepwise regression, while PR, size, and cathepsin D were the remaining factors that predicted cancer-specific OS. The effect of adjuvant treatment on prognosis was also analyzed.

CONCLUSIONS

Both biochemical and clinical parameters have the potential to predict prognosis for N- breast cancer. In this large prospective clinical trial, with a median follow-up of 7.8 years, no individual marker adequately predicted the prognosis for an individual patient. %S activity was the best independent marker, but only 77% of the tumors provided this value. Subset analysis provided improved prognostication, but there were limits to its utility. These data represents a definitive study starting in 1991 and ending in 2002.

Genetically engineered analogs of ascomycin for nerve regeneration

The polyketides FK506 (tacrolimus) and FK520 (ascomycin) are potent immunosuppressants that function by inhibiting calcineurin phosphatase through formation of an FKBP12-FK506/520-calcineurin ternary complex. They also have calcineurin-independent neuroregenerative properties in cell culture and animal models of nervous system disorders. Based on the crystal structure of the FKBP12-FK506-calcineurin complex, we deduced that the 13- and 15-methoxy groups of FK506 or FK520 are important for inhibition of calcineurin phosphatase but not for binding to FKBP12. By genetic modification of the FK520 gene cluster, we generated 13- and 15-desmethoxy analogs of FK520 that contain hydrogen, methyl, or ethyl instead of methoxy at one or both of these positions. These analogs bind FKBP12 tightly, have decreased calcineurin phosphatase inhibition and immunosuppressive properties, and enhance neurite outgrowth in cell cultures. A representative compound was also shown to accelerate nerve regeneration and functional recovery in the rat sciatic nerve crush model.

Development of depolarization-induced calcium transients in insect glial cells is dependent on the presence of afferent axons

Changes in the intracellular Ca(2+) concentration ([Ca(2+)](i)) induced by depolarization have been measured in glial cells acutely isolated from antennal lobes of the moth Manduca sexta at different postembryonic developmental stages. Depolarization of the glial cell membrane was elicited by increasing the external K(+) concentration from 4 to 25 mM. At midstage 5 and earlier stages, less than 20% of the cells responded to 25 mM K(+) (1 min) with a transient increase in [Ca(2+)](i) of approximately 40 nM. One day later, at late stage 5, 68% of the cells responded to 25 mM K(+), the amplitude of the [Ca(2+)](i) transients averaging 592 nM. At later stages, all cells responded to 25 mM K(+) with [Ca(2+)](i) transients with amplitudes not significantly different from those at late stage 5. In stage 6 glial cells isolated from deafferented antennal lobes, i.e., from antennal lobes chronically deprived of olfactory receptor axons, only 30% of the cells responded with [Ca(2+)](i) transients. The amplitudes of these [Ca(2+)](i) transients averaged 93 nM and were significantly smaller than those in normal stage 6 glial cells. [Ca(2+)](i) transients were greatly reduced in Ca(2+)-free, EGTA-buffered saline, and in the presence of the Ca(2+) channel blockers cadmium and verapamil. The results suggest that depolarization of the cell membrane induces Ca(2+) influx through voltage-activated Ca(2+) channels into antennal lobe glial cells. The development of the depolarization-induced Ca(2+) transients is rapid between midstage 5 and stage 6, and depends on the presence of afferent axons from the olfactory receptor cells in the antenna.

MR Virtual Angioscopy of Thoracic Aortic Atherosclerosis in Homozygous Familial Hypercholesterolemia

PURPOSE

The thoracic aorta is an important site of atherosclerotic disease in patients with homozygous familial hypercholesterolemia (HFH). Thoracic aortic atherosclerosis in patients with HFH was assessed with contrast-enhanced MR angiograms using exoscopic and endoscopic virtual angioscopy reconstructions and maximum intensity projections (MIPs).

METHOD

Contrast-enhanced MR angiograms of the thoracic aorta of 15 patients with HFH and 8 normal volunteers were obtained. Perspective surface reconstructions of the MR angiograms including virtual angioscopy views were evaluated by three radiologists blinded to the diagnosis.

RESULTS

Thoracic wall irregularity was depicted on 8 of 15 (53%) patient scans and only 1 of 8 (13%) normal subject scans using surface reconstructions. Wall irregularity scores of patients with HFH were significantly increased compared with controls (2.0 +/- 0.9 vs. 1.0 +/- 0.6; p = 0.008). There was excellent interobserver agreement (weighted kappa = 0.82 +/- 0.12). Virtual endoscopy views added diagnostic confidence compared with exoscopic surface renderings alone. MIP reconstructions were unable to depict wall irregularity.

CONCLUSION

MR angiography with virtual angioscopy of the thoracic aorta depicts nonstenotic wall irregularity of thoracic aortic atherosclerosis in patients with HFH. This may be important for assessing disease progression and response to treatment and may be generalizable to routine (non-HFH) atherosclerosis.

Evaluating training courses for parents of children with cochlear implants

The purpose of this study was to investigate the change in effective communication between parents and children with cochlear implants when the parents attended a modified Hanen training course (Watson 1995). The study demonstrates that the course led to improvement in the effectiveness of the parent-child interaction, as rated by naïve independent observers. The Erber rating scale (Erber et al. 1995) was implemented as a tool for evaluating changes before and after the courses. Using video samples taken at the above intervals, the ratings showed a significant increase in effective communication at the end of the courses.

A novel method for expression and large-scale production of human brain l-glutamate decarboxylase

l-Glutamate decarboxylase (GAD; EC 4.1.1.15) is the rate-limiting enzyme involved in the synthesis of gamma-aminobutyric acid (GABA), the major inhibitory neurotransmitter in the mammalian brain. Imbalance in the conversion of glutamate to GABA has been implicated in a host of human diseases. Studies on the structure, function, and therapeutic use of GAD have been precluded by insufficient quantities of purified active enzyme. Here we report a novel methodology for the expression and large-scale production of enzymatically active, pure, recombinant human GAD65 and GAD67. This method circumvents the sequestering of expressed protein into insoluble inclusion bodies and reduces production of truncated proteins. The availability of sufficient quantities of purified HGAD65 and HGAD67 has allowed for the production of specific polyclonal antibodies that discriminate between the two isoforms. This methodology, in addition to providing key human brain enzymes, may be generally applicable to other systems.

Evaluation of the aortic root by MRI: insights from patients with homozygous familial hypercholesterolemia

BACKGROUND

In homozygous familial hypercholesterolemia (HFH), the aortic root is prone to develop atherosclerotic plaque at an early age. However, the aortic wall and plaque have not yet been assessed in this condition by MRI. We evaluated the aortic root by use of MRI in 17 HFH patients and 12 normal control subjects in a prospective, blinded, controlled study.

METHODS AND RESULTS

Morphological assessment of the aortic root was done with spin-echo and gradient-echo MRI scanning. Comparisons were made with a number of measures of disease severity, including cholesterol-year score, calcium score on electron-beam CT (EBCT), and size of Achilles tendon xanthomas. Atherosclerotic plaque, visible on fat-suppressed images but never on water-suppressed images, was present in 9 HFH patients (53%). Supravalvular aortic stenosis was present in 7 patients with HFH (41%). Maximum supravalvular aortic wall thickness was significantly greater and OD and lumen cross-sectional area (CSA) were smaller in patients than in control subjects (P=0.006, 0.0005, and 0.06, respectively). Maximum wall thickness was associated with a greater calcium score on electron-beam CT (P=0.02). Although the cumulative exposure of the aortic root to cholesterol (the cholesterol-year score) was significantly correlated with the Achilles tendon CSA and vascular calcification, this score did not correlate with the wall thickness or aortic CSA.

CONCLUSIONS

This study not only demonstrates the utility of MRI for detecting and characterizing aortic root atherosclerotic plaque and supravalvular aortic stenosis in HFH patients but also suggests that the LDL receptor plays a direct or indirect role in aortic mural development and vascular growth.

Aortic hypoplasia in homozygous familial hypercholesterolemia

Diagnosis of hypoplastic aortic root with ultrafast computed tomography provides important clinical information in homozygous familial hypercholesterolemic patients with supravalvular aortic stenosis.

Electrocardiographic changes during desipramine and clomipramine treatment in children and adolescents

OBJECTIVE

With the increased use of tricyclic antidepressants in children, and several reports of several sudden deaths associated with desipramine (DMI) treatment, systematic study of their cardiac effects is indicated. In the present study, DMI's and clomipramine's (CMI) short-term effects on the electrocardiogram (ECG) were compared, as well as the long-term effects of CMI.

METHOD

The ECGs of 47 children and adolescents in treatment trials were examined at baseline, after 5 weeks of CMI and of DMI treatment, and during CMI maintenance (mean duration 24.6 months).

RESULTS

At 5 weeks of CMI and of DMI treatment, the heart rate, PR, QRS, and QT-corrected (QTc) intervals on ECG were significantly increased from baseline (p < .05); DMI increased PR and QRS intervals more than CMI (p < .05), and CMI increased QTc more (p < .05). Tachycardia was the most common change (36%). More patients experienced an incomplete intraventricular conduction delay during DMI treatment (23%, 9/39) than during CMI (2%, 1/47) (p < .05). Four patients (9%) acutely developed a prolonged QTc during either DMI or CMI. Long-term maintenance ECGs during CMI treatment (n = 25) were not significantly different from that at week 5, although some individuals developed or resolved specific ECG changes.

CONCLUSION

CMI and DMI both produced ECG changes typically reported for tricyclic antidepressants, and they differed on specific ECG changes. Changes in ECG measures for individuals from short to long term suggest that continued monitoring is required.

A pilot study of amiodarone with infusional doxorubicin or vinblastine in refractory breast cancer

Increasing evidence suggests that P-glycoprotein (Pgp) expression can mediate drug resistance in refractory breast cancer. We studied 33 patients with refractory breast cancer enrolled in a pilot study of oral amiodarone as a Pgp antagonist given in combination with infusional doxorubicin or vinblastine. Whenever possible, tumors were biopsied and Pgp expression was assayed. Patients received either 60 mg/m2 doxorubicin over 96 h or 8.5 mg/m2 vinblastine over 120 h by continuous intravenous infusion. Beginning with the second cycle of chemotherapy, 600-800 mg amiodarone was given orally each day. Patients who experienced toxicity due to amiodarone but were responding to chemotherapy were placed on quinidine. Partial responses were observed in 9 of 33 patients on study and were sometimes observed after the first cycle of chemotherapy, before amiodarone was given, suggesting that some patients may have responded to treatment because of the infusional schedule. Toxicities were primarily the known side effects of the antineoplastic agents and of amiodarone. The major amiodarone toxicity was gastrointestinal, with nausea, vomiting, anorexia, or diarrhea being noted in 21 patients. Biopsy samples were obtained from 29 patients and in 21 cases, viable tumor tissue was present and the results were interpretable. Of the 21 samples, 9 had Pgp expression as determined by immunohistochemical staining; 12 were considered negative. The presence of Pgp expression was associated with an acceleration of the time to treatment failure. Whereas normal-tissue toxicities related to the combination of a Pgp antagonist with chemotherapy were not observed, amiodarone was associated with too many untoward effects to be utilized as a drug resistance-reversing agent.

Cardiopulmonary toxicity of treatment with high dose interleukin-2 in 199 consecutive patients with metastatic melanoma or renal cell carcinoma

BACKGROUND

Administration of recombinant interleukin-2 (rIL-2) can mediate tumor regression in patients with metastatic melanoma and renal cell carcinoma. In response to recent FDA approval of high dose rIL-2 for use in renal cell carcinoma, the authors recent experience with the cardiopulmonary toxicity associated with high dose IL-2 therapy is reviewed.

METHODS

The treatment courses of all patients receiving high dose intravenous bolus rIL-2 from January, 1988, until December, 1992, were evaluated for cardiopulmonary toxicity.

RESULTS

One hundred ninety-nine patients received 310 courses of treatment. There were no treatment-related deaths. Respiratory distress occurred in 3.2% of the courses, requiring intubation in one patient. Three obtunded patients were endotracheally intubated for airway control. Arrhythmias occurred in 6% of the courses (18 patients) with hypotension developing in two of the 199 patients as a result. Eleven of these patients were retreated and recurrent atrial fibrillation developed in two. One episode of significant ventricular tachycardia was noted. Hypotension occurred in 53% of courses; no patients developed hypotension unresponsive to vasopressors. There were no myocardial infarctions; however, 2.5% of patients experienced elevated creatine phosphokinase levels associated with elevated MB isoenzymes attributed to cardiac toxicity. Only one of these patients developed symptoms. Response rates of 19.6% and 15.7% were noted in patients with renal cell carcinoma and melanoma, respectively. Hypotension requiring vasopressors was associated with a significantly improved rate of response in patients with melanoma compared with patients not requiring vasopressors (23.2% vs. 6.5%, P2 = 0.037).

CONCLUSIONS

Although high dose intravenous rIL-2 therapy can be associated with cardiopulmonary toxicity, toxic side effects generally are not severe and are rapidly reversible.

Impact of surgical relief of outflow obstruction on thallium perfusion abnormalities in hypertrophic cardiomyopathy

BACKGROUND

To assess the impact of surgical relief of left ventricular outflow obstruction on myocardial perfusion abnormalities in patients with obstructive hypertrophic cardiomyopathy, 20 symptomatic patients who underwent a septal myectomy or mitral valve replacement were studied with assessment of myocardial perfusion during exercise by 201Tl emission computed tomography before and 6 months after surgery.

METHODS AND RESULTS

Before surgery, 15 patients had myocardial perfusion defects during exercise that completely normalized at rest, one patient had both reversible and fixed perfusion defects, two patients had fixed defects only, and two patients had normal exercise and rest thallium scans. After surgical relief of left ventricular outflow obstruction (basal gradient reduced from 62 +/- 40 to 7 +/- 12 mm Hg, p less than 0.001; peak provokable gradient reduced from 131 +/- 27 to 49 +/- 36 mm Hg, p less than 0.001), repeat exercise thallium studies showed complete normalization of perfusion defects in 11 patients, including the two patients with fixed defects alone before surgery, and improvement in the magnitude and distribution of perfusion defects in five additional patients. This was associated with a significant reduction in the number of patients with reversible regional defects (five patients compared with 13 patients before surgery, p = 0.026) and of patients with endocardial hypoperfusion (four patients compared with 12 patients before surgery, p = 0.024). Furthermore, increased lung uptake of thallium was noted in five patients after surgery, compared with 12 patients before surgery (p = 0.055). Only two patients with reversible perfusion defects before surgery had unchanged postoperative studies. However, four patients acquired new fixed defects as a consequence of surgery, and two of these four had the greatest severity and distribution of left ventricular hypertrophy by echocardiography. These four patients experienced a substantially greater decrease in ejection fraction (-26 +/- 15%) after surgery than the remaining patients (-3 +/- 14%, p less than 0.01).

CONCLUSIONS

Surgical relief of left ventricular outflow obstruction results in normalization or improvement of myocardial perfusion in the majority of patients with reversible and fixed perfusion defects by 201Tl scintigraphy. However, surgery may result in myocardial injury and scarring, with consequent decreased left ventricular ejection fraction in some patients.

Late recurrent Candida endocarditis

Late recurrent Candida endocarditis (LRCE) developed on a prosthetic mitral valve 22 months after treatment for primary native mitral valve endocarditis. The LRCE was difficult to diagnose; results of two dimensional echocardiography and repeated blood cultures were negative. Only transesophageal echocardiography revealed a vegetation and only lysis centrifugation blood cultures demonstrated candidemia. Postmortem examination revealed a large Candida vegetation on the prosthetic valve and Candida in the mitral valve ring. This case and a review of the literature indicate that Candida endocarditis treated with amphotericin B and prosthetic valve replacement may recur months after treatment, and that LRCE, which is difficult to diagnose and treat, may be best prevented by lifelong antifungal suppressive therapy.