Embolic stroke of undetermined source: beyond atrial fibrillation

INTRODUCTION

Embolic stroke of undetermined source (ESUS) accounts for 25% of all cerebral infarcts; only 30% are associated with paroxysmal atrial fibrillation (AF). Various biochemical, electrocardiographic, and echocardiographic findings may suggest left atrial damage and increased risk of embolism in the absence of clinically documented AF or atrial flutter. In this review, we analyse the available evidence on atrial cardiopathy or atrial disease, its involvement in ESUS, and its identification through electrocardiographic, echocardiographic, and serum markers and its possible therapeutic implications.

DEVELOPMENT

A systematic search was conducted on MEDLINE (PubMed) using the following MeSH terms: MeSH [ESUS]+[atrial cardiopathy]+[atrial fibrillation]+[interatrial block]+[treatment]. We selected what we considered to be the most useful original prospective or retrospective studies and systematic reviews. We then read the full texts of the articles and checked the references cited in each article. We analyse epidemiological and demographic variables of patients with ESUS, as well as recent evidence related to presentation and prognosis and factors associated with recurrence and mortality. We review the contribution of atrial cardiopathy diagnosis prior to the detection of AF and the clinical, electrocardiographic, and echocardiographic variables and the biochemical markers associated with its development and its potential contribution to cerebral embolism.

CONCLUSIONS

The systematic search of biochemical and electrocardiographic, and echocardiographic alterations can be useful to identify ESUS patients at higher risk of recurrence.

Embolic stroke of undetermined source: Beyond atrial fibrillation

INTRODUCTION

Embolic stroke of undetermined source (ESUS) accounts for 25% of all cerebral infarcts; only 30% are associated with paroxysmal atrial fibrillation (AF). Various biochemical, electrocardiographic, and echocardiographic findings may suggest left atrial damage and increased risk of embolism in the absence of clinically documented AF or atrial flutter. In this review, we analyse the available evidence on atrial cardiopathy or atrial disease, its involvement in ESUS, and its identification through electrocardiographic, echocardiographic, and serum markers and its possible therapeutic implications.

DEVELOPMENT

A systematic search was conducted on MEDLINE (PubMed) using the following MeSH terms: MeSH [ESUS]+[atrial cardiopathy]+[atrial fibrillation]+[interatrial block]+[treatment]. We selected what we considered to be the most useful original prospective or retrospective studies and systematic reviews. We then read the full texts of the articles and checked the references cited in each article. We analyse epidemiological and demographic variables of patients with ESUS, as well as recent evidence related to presentation and prognosis and factors associated with recurrence and mortality. We review the contribution of atrial cardiopathy diagnosis prior to the detection of AF and the clinical, electrocardiographic, and echocardiographic variables and the biochemical markers associated with its development and its potential contribution to cerebral embolism.

CONCLUSIONS

The systematic search of biochemical and electrocardiographic, and echocardiographic alterations can be useful to identify ESUS patients at higher risk of recurrence.

30 Informant-Reported Decline Associates with Silent Acute Stroke Lesions and Worse Small Vessel Disease in Mild Stroke Patients

Introduction

Small vessel disease (SVD) commonly causes stroke and dementia. Early clinical predictors of disease progression are lacking. We aimed to determine whether informant reports of chronic cognitive/functional decline, prerequisites for dementia diagnosis, are associated with (a)baseline SVD burden, measured by Fazekas scores and (b)SVD change, measured by incident subcortical Diffusion-weighted Imaging (DWI) lesions.

Method

We prospectively recruited patients with mild ischaemic stroke, performed diagnostic MRI, and invited participants to repeat MRI 3- to 6-monthly. Informants completed the Informant Questionnaire for Cognitive Decline in the Elderly (IQCODE) prior to baseline visit, a 16-item questionnaire which assesses patients’ cognitive and functional decline in the preceding ten years. Scores range from 1–5: a score above 3.3 has high sensitivity/specificity for dementia post-stroke. We conducted linear regression with IQCODE as the dependent variable, adjusting for age, sex, baseline MoCA, disability (modified Rankin Scale).

Results

We recruited 106 participants (mean age 67 years;range 40–86;33% female). Ninety-three informant questionnaires were returned. IQCODE associated with baseline Fazekas score; Fazekas 6 (β = 0.28, p = 0.04) vs. Fazekas 3 (β = 0.03, p = 0.67), R2 = 0.11, adjusted for age, sex, baseline MoCA, disability.

Incident DWI lesions were common (15/106; 14/15 subcortical; no active embolic sources; median 67 days post-stroke). Four were asymptomatic, two reported stroke-like symptoms and nine had neuropsychiatric/non-focal symptoms. IQCODE was higher in those with a new lesion vs. without (β = 0.21, p = 0.02), R2 = 0.09, while age (β = −0.004, p = 0.19), MoCA (β = −0.006, p = 0.56) and disability (β = 0.06, p = 0.2) were not.

Conclusions

Higher SVD burden and incident, mostly “silent” stroke lesions associate more strongly with informant concerns of cognitive/functional decline than age or objective cognitive tests. These findings are novel in an ischaemic stroke population and the first to assess IQCODE/SVD progression. Future work should determine whether combining informant reports with imaging features of small vessel disease improves early detection of dementia.

Abstract P1-15-01: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Metzger Filho O, Janiszewska M, Guo H, Yardley D, Mayer I, Spring L, Arteaga C, Wrabel E, DeMeo M, Freedman R, Tolaney S, Waks A, Bardia A, Parsons H, Partridge A, Mayer E, King T, Polyak K, Viale G, Winer E, Krop I. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-15-01.

Abstract P5-04-23: Enhancing the activity of a novel estrogen receptor coregulator binding modulator (ERX-11) against ER-positive therapy resistant breast cancer

Background:We had previously reported a novel small molecule, ERX-11, that directly interacts with ER and blocks the interaction between a subset of coregulators with both native and mutant forms of ER. ERX-11 effectively blocks ER oncogenic signaling and has potent anti-proliferative activity against therapy-sensitive and therapy-resistant human breast cancer cells. To enhance the clinical translation of ERX-11, we sought to pursue both lead optimization and evaluate combinations of ERX-11 with other approved agents in breast cancer.

Methods: We designed, synthesized and tested 500 derivatives of ERX-11 in multiple models of ER+ breast cancer. We also tested combinations of ERX-11 with multiple agents, including other ER targeting agents, chemotherapies and CDK4/6 inhibitors. We tested the effect of combination therapy using breast cancer cells with acquired resistance (Tamoxifen, Letrozole, Ribociclib resistant) and engineered models that express ER mutations. In vitro activity was tested using Cell titer glo, MTT, and apoptosis assays. Mechanistic studies were conducted using Western blot, reporter gene assays and RNA-seq analysis. Xenograft, patient derived xenograft (PDX), patient derived explant (PDE) and xenograft derived explant (XDE) models were used for preclinical evaluation and toxicity.

Result: Evaluation of 500 analogs of ERX-11 identified a number of leads with differential activity against ER+ and ER- breast cancer cells, identified several analogs including ERX-144, 208, 296, 315 with nanomolar potency against ER+ and therapy-resistant ER+ breast cancers. Validation of the mechanism of action of these analogs is ongoing. The combination of ERX-11 and palbociclib significantly blocked ER-mediated and ER-coregulators mediated oncogenic signaling and showed potent anti-proliferative activity against both endocrine therapy-sensitive and resistant breast cancer cells. In addition, ERX-11 inhibited ribociclib-resistant ER+ cell proliferation in a dose dependent manner. Mechanistic studies using IP-Mass spectrometry demonstrated that ERX-11 and palbociclib blocks the interaction between larger subset of coregulators with ER in therapy resistant breast cancer models. ERX-11 and palbociclib both exhibited potent anti-proliferative activity against therapy-sensitive and therapy-resistant ER+ve breast cancer cells, in xenograft models and in PDEs. Importantly, combination therapy of ERX-11 and palbociclib synergistically reduced the growth of tamoxifen and letrozole resistant xenograft tumors compared to either drug alone. Mass spec based DIA analyses and RNA-seq studies revealed that combinational treatment uniquely activated p53, unfolded response mediated apoptotic pathways, altered DNA damage response and suppressed E2F and Myc target genes. Biochemical studies confirmed combination therapy significantly altered E2F1, ER and DNA damage response pathways.

Conclusion: We have successfully pursued two avenues to improving ERX-11 for clinical translation. We have developed ERX-11 analogs with higher potency against ER+ breast cancer. We have shown that combinational treatment with ERX-11 and palbociclib may overcome endocrine therapy resistance and CDK4/6 inhibitor (ribociclib) resistance.

Citation Format: Viswanadhapalli S, Ma S, Lee T-K, Sareddy GR, Liu X, Ekoue D, Alluri A, Luo Y, Kassees K, Arteaga C, Alluri P, Weintraub SE, Tekmal RR, Ahn J-M, Raj GV, Vadlamudi RK. Enhancing the activity of a novel estrogen receptor coregulator binding modulator (ERX-11) against ER-positive therapy resistant breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-23.

Abstract PD7-10: Neoadjuvant trial with letrozole identifies PRR11 in 17q21-23 amplicon as a resistance mechanism to endocrine therapy in ER-positive breast cancer

Approximately 20% of patients with early ER+ breast cancer (BC) treated with adjuvant antiestrogen therapy relapse with metastatic disease. Previously, we identified 3 amplicons (11q11.3, 8p11.23, and 17q21-23) associated with endocrine-resistance (Giltnane et al. Sci Transl Med 2017). The 17q21-23 amplicon has been associated with highly proliferative luminal B tumors and cancers with high genomic instability. A causal role of this region in endocrine resistance is unclear. We performed whole transcriptome analysis on RNA extracted from 58 ER+ breast cancers of patients treated with letrozole for 5.4-9.2 months (median 7.2 months). PRR11 (Proline rich 11), located in 17q21-23, was significantly upregulated in non-responding tumors as defined by cancer relapse after a median follow up of 5 years and/or a preoperative endocrine prognostic index (PEPI) ≥4. Differential gene expression analysis between tumors expressing low vs high PRR11 mRNA showed that BC signatures associated with proliferation, cell cycle, IGF-1 and PI3K signaling were enriched in tumors with high PRR11 expression. In the Metastatic Breast Cancer Project and TCGA, PRR11 amplification was higher in metastatic vs. primary BCs (16.5% and 8.5%, respectively; Fisher's p=0.0088). Gene Set Enrichment Analysis of mRNA expression in METABRIC and TCGA revealed significant enrichment of hallmark gene sets associated with proliferation in PRR11 amplified ER+ BCs. Genome-scale RNAi screening in Project Achilles showed that among all genes in the 17q21-23 amplicon, PRR11 knockdown results in the 4th strongest anti-proliferative effect in MCF7 cells. PRR11 knockdown with siRNA inhibited proliferation, cell cycle progression, and RB phosphorylation in HCC1428 LTED (long-term estrogen deprived), MCF7 LTED, and fulvestrant-resistant MCF7 cells. Using a PCR array with 84-cell cycle genes, we identified SKP2, CDKN1A, CCNB2, CCNA2, CKS2 and CCNB1 as genes downregulated by PRR11 knockdown. Except for CDKN1A, expression of all those genes was elevated ER+ BCs with PRR11 gain or amplification in TCGA. PRR11 associates with the p85 regulatory subunit of PI3K via its SH3 domain. We speculated this association would suppress p85 homodimers, thus permitting binding of PI3Kα (p110α)-p85 dimers to IRS1 and, hence, activating PI3K/AKT. To test this, we co-transfected HEK293T cells with HA-p85 and FLAG-p85. Transfection of PRR11 into these HEK293T cells reduced HA-p85 and FLAG-p85 homodimers as shown by HA and FLAG pulldowns followed by FLAG and HA immunoblots, respectively. Finally, PRR11 knockdown resulted in a reduction of p110a and S473 P-AKT levels and inhibition of IGF-1/2 stimulated P-AKT. Not inconsistent with these data, PRR11 amplification and PIK3CA mutations in METABRIC and TCGA are exclusive of each other, suggesting these alterations are functionally linked with the same signaling pathway. These data support a role of PRR11 in PI3K/AKT activation that may be causal to resistance to estrogen deprivation. We propose PRR11, located in the 17q21-23 amplicon, is a potential mediator of resistance to antiestrogen therapy by amplifying PI3K/AKT signaling, suggesting PI3K may be a therapeutic target in ER+ BCs harboring PRR11 amplification.

Citation Format: Lee K-M, Guerrero-Zotano A, Formisano L, Jansen V, Gonzalez Ericsson P, Arteaga C. Neoadjuvant trial with letrozole identifies PRR11 in 17q21-23 amplicon as a resistance mechanism to endocrine therapy in ER-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD7-10.

Abstract PD3-06: Neratinib + fulvestrant for HER2-mutant, HR-positive, metastatic breast cancer: Updated results from the phase 2 SUMMIT trial

Background: HER2 mutations define a rare subset of metastatic breast cancer (MBC) with a unique mechanism of oncogenic addiction to HER2 signaling. Neratinib, an irreversible pan-HER tyrosine kinase inhibitor, has demonstrated single-agent clinical activity in HER2-mutant MBC. In HER2-mutant, HR+ MBC, neratinib + fulvestrant (N+F) appears synergistic vs single-agent neratinib, possibly due to more complete inhibition of bi-directional signaling between HER2 and estrogen receptors. Here we describe interim efficacy results of the expanded HER2-mutant, HR+ MBC cohort treated with N+F from SUMMIT (NCT01953926).

Methods: HR+ MBC patients (pts) with HER2 mutations documented by local testing received oral neratinib 240mg qd and intramuscular fulvestrant (labeled dose). Intensive loperamide prophylaxis was mandatory during cycle 1. Efficacy endpoints include objective response rate at week 8 (ORR8); confirmed objective response rate (ORR); clinical benefit rate (CBR); duration of response (DOR); progression-free survival (PFS); response was assessed by RECIST 1.1 and/or PET Response Criteria. Genomic profiling from fresh/archival tumor tissues and/or plasma cfDNA was performed retrospectively by next-generation sequencing (MSK-IMPACT).

Results: As of 18 May 2018, 46 HER2-mutant HR+ MBC pts have been treated with N+F. Most pts were pretreated, with 91% having received prior anti-cancer medication for MBC (range 0–10). ORR was 33% and median DOR in the 15 pts with a confirmed response was 9.2 months (95% CI 3.9–18.5). Twenty-four pts had prior fulvestrant exposure, and 19 had received prior CDK4/6i-based therapy. Clinical activity was observed with ORRs of 17% and 26% in prior fulvestrant-treated and prior CDK4/6i-treated pts, respectively. ORRs by HER2 mutation were: V777L 63% (5/8 pts); S310F/Y 67% (4/6 pts); G778_P780dup 50% (3/6 pts). Diarrhea was the most common adverse event (grade 3, 24%; grade 4, 0%). Median cumulative duration of grade 3 diarrhea was 3 days. There were no treatment discontinuations due to diarrhea.

 Neratinib + fulvestrantOutcomeaAll patients (N=46)Prior fulvestrant (N=24)Prior CDK4/6i-based therapy (N=19)ORR8 – n (%)19 (41.3)8 (33.3)7 (36.8)95% CI27.0–56.815.6–55.316.3–61.6ORR – n (%)15 (32.6)4 (16.7)5 (26.3)95% CI19.5–48.04.7–37.49.1–51.2DOR for each responder, months 5.6b; 9.2; 9.6b; 18.55.6b; 5.7b; 9.3; 9.6b; 12.9bCBR – n (%)27 (58.7)11 (45.8)9 (47.4)95% CI43.2–73.025.6–67.224.4–71.1Median (95% CI) time to event,c monthsPFS3.9 (3.6–5.7)3.7 (3.5–12.8)3.9 (1.9–NA)DOR9.2 (3.9–18.5)NANAaFor pts with both RECIST- and PET-evaluable lesions, the best of either RECIST or PET response was used to determine response; the earliest progression by RECIST or PET was used for progression; bPt has not progressed; cKaplan-Meier analysis; NA, not applicable

Conclusions: N+F demonstrates encouraging clinical activity with durable responses in heavily pretreated pts with HER2-mutant, HR+ MBC. Of note, responses were observed in pts who had received prior fulvestrant or CDK4/6 inhibitors. No new safety signals were identified; the rate of diarrhea was similar to single-agent neratinib and not dose limiting. Updated data after additional follow-up and genomic data will be presented.

Citation Format: Smyth LM, Piha-Paul SA, Saura C, Loi S, Lu J, Shapiro GI, Juric D, Mayer IA, Arteaga C, de la Fuente M, Brufksy AM, Mau-Sørensen M, Arnedos M, Moreno V, Sohn J-H, Schwartzberg L, Gonzàlez-Farré X, Cervantes A, Mann G, Shahin S, Cutler, Jr. RE, Eli LD, Xu F, Bagulho T, Lalani AS, Bryce R, Solit DB, Hyman DM, Meric-Bernstam F, Baselga J. Neratinib + fulvestrant for HER2-mutant, HR-positive, metastatic breast cancer: Updated results from the phase 2 SUMMIT trial [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr PD3-06.

Mite species identification in the production of allergenic extracts for clinical use and in environmental samples by ribosomal DNA amplification

The identification of allergy-causing mites is conventionally based on morphological characters. However, molecular taxonomy using ribosomal DNA (rDNA) may be particularly useful in the analysis of mite cultures and purified mite fractions in the production of allergenic extracts. Full-length internal transcribed spacers (ITS1 and ITS2) were obtained from Dermatophagoides farinae, Dermatophagoides pteronyssinus, Dermatophagoides microceras and Euroglyphus maynei (Astigmata: Pyroglyphidae), Glycyphagus domesticus and Lepidoglyphus destructor (Astigmata: Glycyphagidae), Tyrophagus fanetzhangorum, Tyrophagus putrescentiae, Tyrophagus longior, Tyrophagus neiswanderi, Acarus farris and Acarus siro (Astigmata: Acaridae), and Blomia tropicalis (Astigmata: Echymopodidae), using mite-specific primers. Polymerase chain reaction (PCR) products were digested with HpaII and RsaI restriction enzymes in order to produce species-specific PCR restricted fragment length polymorphism (RFLP) profiles. A semi-nested re-amplification step was introduced before the RFLP in order to apply the method to environmental samples. Results demonstrate that rDNA sequences can be used for the unambiguous identification of mite species. The PCR-RFLP system allows the identification of species in purified mite fractions when the availability of intact adult mite bodies for morphological identification is limited. This reliable and straightforward PCR-RFLP system and the rDNA sequences obtained can be of use in the identification of allergy-causing mite species.

Abstract PD5-1: The type II TGFb receptor neutralizing antibody, TR1, abrogates the tumor-initiating cell (TIC) population in triple negative breast cancer (TNBC) via inhibition of SMAD and non-SMAD pathways

Tumor-initiating cells (TICs) or cancer stem cells (CSCs) are resistant to chemotherapy and have been associated with metastatic recurrences and poor patient outcome. We have shown that the TGFb pathway plays a crucial role in the expansion of TICs and that inhibition of the type I TGFβ receptor (ALK5) decreases chemotherapy-resistant TICs. Further, a TGFβ-responsive gene signature is enriched in TNBCs upon treatment with chemotherapy and is predictive of poor prognosis (Bhola et al. JCI 2013). Herein we investigated the molecular and antitumor effects of TR1, a TGFβRII neutralizing antibody currently in phase I clinical trials, against TNBC. TR1 recognizes the TGFβ ligand binding epitope in the extracellular domain of TGFβRII; it blocks ligand binding in the nM range. Small molecule TGFβRI kinase inhibitors are another approach to inhibit TGFβ/SMAD signaling. However, they cross-react with other type I receptors (ALK1, 4, 7), some of which are important for normal physiology. Furthermore, TGFβRII can induce EMT in breast cancer cells independent of dimerization with TGFβRI. Therefore, we hypothesized that, by neutralizing TGFβRII, TR1 can abrogate the breast TIC population via inhibition of SMAD and non-SMAD signaling.

Using the pCAGA12-luciferase reporter to assess SMAD-dependent transcriptional activity, TR1 decreased luciferase activity in TNBC cell lines (SUM159 and BT549) and steady-state levels of P-SMAD2, suggesting it inhibited autocrine TGFβ signaling. TR1 decreased the TIC fraction as identified by FACS analysis of cell line-specific TIC markers (ALDH for SUM159; CD44hi/PROCR+ for BT549; PROCR+/ESA+ for MDA231 cells). Although TR1 displayed no effects on TNBC growth in vitro, it decreased tumor growth in vivo. We used a phospho-kinase array (45 kinases) to elucidate the non-SMAD pathways altered by TR1. TR1 decreased phosphorylated EGFR (Tyr1068) and STAT3 (Tyr705) in TNBC cell lines. By flow cytometry, the cell-surface expression of EGFR was also lowered upon treatment with TR1. TR1 also reduced P-ERK1/2 and P-Akt (Ser473) levels, and lowered NFκB transcriptional activity as measured by luciferase reporter assay. Using a cytokine array (120 cytokines) and qRT-PCR we observed that TR1 decreased the expression and release of cytokines involved in TIC enrichment such as IL-6 and IL-8. Inhibition of EGFR (with gefitinib) and MEK1/2 (with selumetinib) decreased the TIC population while augmenting pCAGA luciferase activity. The combination of SMAD2 siRNA with each EGFR or MEK inhibitors significantly decreased the TIC population. We speculate based on these data that inhibition of both SMAD and non-SMAD signaling is necessary for complete abrogation of TICs. This may explain the efficacy of TR1 as a single agent.

These findings suggest that targeting TGFβRII with TR1 exerts its anti-tumor effects via inhibition of both SMAD and non-SMAD (EGFR, ERK) pathways that are important to TIC survival. The results also encourage combination therapies of chemotherapy with TR1 to reduce tumor recurrences in patients with TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr PD5-1.

PD08-04: Inhibition of the TGFb/TGFbR2 Pathway Prevents Enrichment of Drug-Resistant Breast Cancer Stem Cells by Anti-Cancer Chemotherapy

Triple-negative breast cancer (TNBC) is the most virulent form of breast cancer and is associated with a worse prognosis compared to hormone receptor- and HER2−positive tumors. The standard treatment of TNBC is cytotoxic chemotherapy. TNBC patients tend to display a good initial response to chemotherapy; however, they exhibit higher recurrence rates and overall poor long term survival. Reasons for this high metastatic recurrence rate and mortality are believed to be the existence of a chemo-resistant tumor-initiating population called cancer stem cells (CSCs). CSCs are defined as cells with the ability to self-renew, differentiate into non-tumorigenic cells, and initiate tumors in vivo. CSCs isolated from breast cancer tissue display increased transforming growth factor (TGF) β and TGFβ type II receptor (TGFβR2) mRNA expression compared to the non-CSC population. Furthermore, breast CSCs exhibit characteristics of an epithelial to mesenchymal transition (EMT), a process driven by the TGFβ signaling and associated with metastatic progression. Therefore, we hypothesize that inhibiting the TGFβ/TGFβR2 pathway can abrogate the breast CSC population and sensitize TNBC to chemotherapy, thus reducing metastatic recurrences and tumor progression.

To address this hypothesis, we used the TNBC cell lines SUM159 and BT549. We examined the effect of TGFβ1, the TGFβ receptor I/II kinase inhibitor LY2157299, the TGFbRII receptor and TGFb1 neutralizing antibodies TR1, and LY2424087 and paclitaxel on the CSC population of these cell lines by 1) flow cytometric analysis of stem cell markers (ALDH, CD44, and PROCR); and 2) mammosphere formation assays. In both cell lines, LY2157299, LY2424087, and TR1 abrogated TGFβ-mediated CSC enrichment and mammosphere formation (p≤0.01). Treatment with paclitaxel resulted in an enrichment of CSCs as measured by FACS and mammosphere formation (p≤0.005) both in vitro and in SUM159 xenografts established in athymic mice. Further, treatment with paclitaxel upregulated TGFβR2 and TGFβ1 mRNAs and phosphorylated SMAD2 levels in CSCs sorted from post-therapy SUM159 xenografts. RNAi-mediated knockdown of TGFβR2 in BT549 cells decreased mammosphere formation but did not affect the proportion of CSCs analyzed by FACS (p≤0.005 and p=0.03, respectively). TGFβR2 and SMAD4 siRNA decreased the CD44hi/CD24lo population in both cell lines. SMAD4 siRNA also decreased CSCs, mammosphere formation, and viability in SUM159, BT549, and MDA-231 basal-like and HCC1954 (HER2+) cells. SMAD4 knockdown resulted in a significant decrease in the CSC-associated genes interleukin-8 (IL-8) and Nanog. Finally, a combination of either LY2157299 or SMAD4 siRNA with paclitaxel decreased both stem cell marker expression, IL-8 and mammosphere formation compared to each treatment alone (p≤0.006). These findings suggest that autocrine TGFb signaling plays a maintenance role in breast CSCs viability. Second, blockade of the TGFb/TGFbR2 pathway with genetic or pharmacological inhibitors can ameliorate or prevent the enrichment of drug-resistant CSCs by anti-cancer chemotherapy. These studies provide a rationale for studies of chemotherapy ± TGFb inhibitors in patients with TNBC using stem cell markers as surrogates of clinical response.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD08-04.

P1-07-19: Analysis of HER2−Status in Breast Cancer by Mass Spectrometry in Archival, Formalin-Fixed Tissues

HER2 (ERBB2) is overexpressed in about 25% of breast cancers and predicts clinical benefit from trastuzumab, as well as response to anthracycline-based chemotherapy. Fluorescence in situ hybridization (FISH) to detect HER2 gene copy number and immunohistochemistry (IHC) to detect HER2 protein levels are approved by the FDA to identify HER2−positive (H2) tumors. However, the 2007 ASCO/CAP report concluded that approximately 20% of HER2 testing may be inaccurate. Further, the available data did not clearly demonstrate clear superiority of either IHC or FISH as a predictor of benefit from anti-HER2 therapy. Discordance between these methods is as high as 5%. Thus, novel complementary quantitative methods for interrogating HER2 expression in tumors are needed.

Targeted protein analysis by multiple reaction monitoring mass spectrometry (MRM-MS) offers a powerful approach to configure assays for specific proteins without using antibodies. Our studies using this platform have demonstrated applicability to formalin-fixed, paraffin-embedded (FFPE) specimens. In the current studies, we used this approach to measure signals from two tryptic peptides specific to HER2, one each from the extracellular and intracellular domains, selected from among 28 candidates based on their signal intensity and sharpness of their chromatographic profiles. Preliminary studies with a HER2−overexpressing BT474 xenograft in mice demonstrated quantitation and detected previously reported HER2 ectodomain shedding. Subsequent analysis of FFPE tissue from five H2 and five triple-negative (TN) tumors yielded measurement of at least 1 femptomole of receptor for H2 tumors and less than 0.2 femptomole of receptor for TN tumors per microgram of digest analyzed. If we assume 200 picograms of protein per cell, the results suggest 110,00 to 468,000 receptors per cell in the H2 tumors and only 2,000 to 14,000 receptors per cell in the TN tumors. Despite significant biological variability in receptor levels measured among the specimens of each type, a clear separation of the H2 and TN tumors was achieved based on the peptide quantitation. This preliminary study demonstrates the potential of MRM-MS in FFPE tissue to provide an alternate approach to IHC-based protein analysis. MRM-MS offers the potential for more, accurate and robust HER2 quantification in clinical breast cancer tissues. The next phase of this work will encompass a larger sample set, including tumors with equivocal and negative FISH and/or IHC test results. Correlation with response to anti-Her2 therapy will be performed in samples with available follow-up data.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P1-07-19.

Transcriptional and Post-Translational Upregulation of HER3 (ErbB3) Counteracts Antitumor Effect of HER2 Tyrosine Kinase Inhibitors

We hypothesized that sustained inhibition of HER3 and its output to PI3K/Akt is required for the optimal antitumor effect of HER2 inhibitors. Therefore, we examined the temporal effect of the HER2 tyrosine kinase inhibitor (TKI) lapatinib (lap) on feedback upregulation of active HER3 in HER2-overexpressing breast cancer cells. A time course with lap-treated cells showed 3 to 5-fold upregulation of HER3 RNA and protein, beginning at 4 h and increasing through 48 h. P-Tyr immunoblot of HER3 immunoprecipitates revealed recovery of HER3 phosphorylation at and beyond 13 h of treatment. Site-specific antibodies revealed HER3 phosphorylation at Y1197 and Y1289, two of the six p85 binding sites in HER3. Recovery of P-HER3 correlated temporally with recovery of T308 P-Akt. The upregulation of HER3 RNA upon treatment with lap suggested that inhibition of active HER2 and PI3K/Akt derepresses the transcription factor FoxO3a. Putative FoxO3a binding sites were identified within the 5' flanking region upstream of the HER3 transcription start site. Transfection with FoxO3a siRNA reduced basal and lap-induced HER3 RNA levels 2 to 5-fold compared to control cells. Conversely, overexpression of FoxO3a increased HER3 RNA 2.5-fold, which could be further enhanced by lap treatment. In addition to these transcriptional mechanisms, the recovery of P-HER3 upon lap-induced inhibition of HER2 suggested engagement of another tyrosine kinase transactivating HER3 and/or that HER2 had been incompletely inhibited by the TKI. However, IGF-IR, Src, and MET TKIs did not inhibit the recovery of P-HER3. On the other hand, the addition of trastuzumab (tz) to lap-treated cells prevented recovery of P-HER3, suggesting that disruption of a ligand-independent HER2-HER3 interaction was involved in partial maintenance of HER3 phosphorylation.The upregulation of HER3 RNA and partial maintenance of P-HER3 and P-Akt suggested that combined inhibition of HER2 and HER3 will synergistically inhibit tumor cell viability. Transfection with HER3 siRNA sensitized HER2+ breast cancer cells to each lap and tz as assessed by Apo-BrdU (apoptosis) and 3D-Matrigel growth assays. Further, treatment with AMG-888, a HER3 monoclonal antibody (AMGEN-U3), sensitized cells to each lap and tz. Ongoing studies include the treatment of BT474 xenografts in athymic mice with lap ± AMG-888 using [18F]-FDG-PET as a non-invasive imaging biomarker to predict treatment outcome. Finally, we examined HER3 levels by immunohistochemistry in sections from tumor blocks of patients enrolled in a neoadjuvant trial where lap was given alone during the first 6 weeks of therapy. The percent and intensity of tumor cell staining was calculated as a histoscore (Human Pathol. 26:291, 1995). On week 2 of therapy, HER3 levels increased 135% above pre-therapy levels (n=8; p=0.03, Mann-Whitney). These data suggest that upon inhibition of the HER2 tyrosine kinase, HER2+ breast cancers 1) upregulate HER3 by transcriptional mechanisms and partially maintain HER3 function by post-translational mechanisms; 2) this compensatory phosphorylation of HER3 partially maintains PI3K/Akt; and 3) inhibition of HER3 sensitizes HER2-dependent breast cancer cells to HER2 inhibitors.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 63.

Differential Signaling by ErbB Receptor (HER) Dimers: Implications for Response to Anti-HER2 Therapies in Breast Cancer

The ErbB family of receptor tyrosine kinases comprises of EGFR, HER2, HER3 and HER4. Ligand binding induces receptor homo- and heterodimerization and activation of downstream signaling. No ligand(s) have been identified for HER2. Recruitment of HER2 to ligand-activated co-receptors potentiates signaling by HER2-containing heterodimers. To identify differential signaling induced by HER2/HER3 and HER2/EGFR heterodimers and HER2 homodimers, we developed a cell system where HER2 dimerization can be conditionally regulated. A retroviral vector encoding HA-tagged full-length human HER2 fused to ligand-binding domain of FK506 binding protein (FKBP) in the C-terminus was stably transduced into MCF10A mammary epithelial cells. Treatment of MCF10A-HER2-FKBP-HA cells with the intracellular dimerizer AP1510 resulted in homodimerization and tyrosine phosphorylation of the HER2 chimera. The EGFR ligands EGF and TGFα and the HER3 ligand heregulin induced HER2/EGFR and HER2/HER3 heterodimers. Microarray analysis with RNA isolated from vehicle, AP1510, TGFα and heregulin treated cells identified unique transcriptional activities associated with HER2/HER2, HER2/HER3 and HER2/EGFR induced signaling. Ingenuity Pathway analysis of the microarray data showed that HER2 homodimers had the most significant effect on the “G2/M DNA damage checkpoint regulation pathway” whereas HER2/EGFR dimers had the most pronounced effect on the “pyrimidine metabolism pathway”. Active HER2/HER3 dimers affected the NF-κB signaling pathway the most.To determine if differential signaling by ErbB dimers have any implications for the response to anti-HER2 therapies, we treated MCF10A-HER2-FKBP-HA cells with AP1510, TGFα or heregulin in the presence or absence of trastuzumab, pertuzumab or lapatinib. In 3D Matrigel, AP1510-treated cells formed invasive acini while untreated cells failed to grow. EGF and TGFα and heregulin also stimulated acini growth in 3D. The anti-HER2 antibody trastuzumab completely inhibited AP1510-stimulated but not EGF, TGFα, or heregulin-stimulated growth. Lapatinib, a dual inhibitor of the HER2 and EGFR tyrosine kinases, blocked EGF, heregulin, and AP1510-induced growth. Pertuzumab, an antibody that blocks ligand-induced HER2 heterodimerization, inhibited heregulin-induced but not AP1510-induced growth. Reverse Phase Protein Array performed with lysates from cells treated with AP1510, TGFα or heregulin indicated that AP1510 failed to activate S473 p-AKT. This is a key enzyme in the PI3K pathway, which has been associated with resistance to HER2 inhbitors. Western blot analyses showed that AP1510 induced p-ERK whereas TGFα and Heregulin activated p-AKT. Binding assays with 125I-labeled trastuzumab indicated that treatment with AP1510 enhanced binding of trastuzumab compared to untreated cells. This result suggests that HER2 homodimers present a conformation to which trastuzumab binds better. Taken together, these data suggest that 1) because of their inability to activate Akt, cells dependent on HER2-containing homodimers are less able to bypass trastuzumab action; and 2) high levels of HER2 homodimers in breast cancers with HER2 gene amplification may represent a biomarker predictive of response to trastuzumab.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 705.

A Phase Ib Trial of Erlotinib, an EGFR Inhibitor, and Everolimus (RAD001), an mTOR Inhibitor, in Patients with Metastatic Breast Cancer

Background: The EGFR and the PI3K pathways have been implicated in breast cancer's prognosis and mechanisms of resistance to conventional therapies. Preclinical data have shown synergy between EGFR and PI3K/Akt pathway blockade. Therefore, we conducted a phase Ib trial to determine the maximum tolerated dose (MTD) and antitumor activity of Erlotinib, an oral EGFR tyrosine kinase inhibitor, and Everolimus (RAD001), an oral mTOR inhibitor, given daily to patients with metastatic breast cancer.Materials and Methods: This was an open-label, phase I dose-escalation study. Everolimus was started at 2.5 mg/d and Erlotinib was started at 100 mg/d on a 28-day treatment cycle. Doses were escalated over 6 levels (Everolimus 2.5, 5 or 10 mg daily with Erlotinib 100 or 150 mg daily). Treatment was continued until consistent dose-limiting toxicity (DLT) was observed or until progression of disease. All toxicities were documented using the NCI CTC v.3. Disease assessment was done every 2 months after initiation of therapy.Results: A total of 14 patients were enrolled on the first 2 dose levels (Erlotinib 100 mg with Everolimus 2.5 mg [level I] and 5 mg [level II] daily). Eight patients were enrolled on level I and 6 patients were enrolled on level II. The median age of all patients enrolled was 55 years of age, and 92% of them had visceral disease. Half of the patients had ER+ disease, 35% had HER2 + disease, and 15% had triple-negative disease. The median number of previous chemotherapy regimens in the metastatic setting was 4. Two patients on the level II cohort discontinued trial due to grade 3 stomatitis prior to their first disease assessment. Of the remaining 13 patients, 11 progressed at the time of their first disease assessment, and 1 patient on the dose level I cohort had a partial response that lasted for 7 months. The most common toxicities were rash (16%), transaminase elevation (15%), stomatitis (13%), fatigue (7%) and diarrhea (5%). Grade 3 and 4 toxicities were overall uncommon (3.5%), and mostly consisted of stomatitis, transaminase elevation and rash. Stomatitis was the only DLT, and was seen at dose level II. The MTD was determined to be Erlotinib 100 mg and Everolimus 2.5 mg daily.Discussion: In patients with metastatic HER2-negative breast cancer the combination of Erlotinib and Everolimus was overall well tolerated, but clinically ineffective from a tumor activity point of view in this heavily pre-treated patient population. Stomatitis was one of the most common toxicities and also the DLT in the cohort treated with dose level II. In view of the plethora of novel active agents currently in clinical trials in breast cancer, we do not believe the above combination warrants further testing in this disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3094.

Endoscopic endonasal surgery complication: new methods of intracavernous internal carotid artery injury treatment

OBJECTIVES

To present new interventional neuroradiology methods of management of an ICA injury during functional endoscopic sinus surgery (FESS).

CASE

The authors report the case of a patient who presented an ICA injury during a FESS and who could undergo an embolization. This embolization stopped the epistaxis and saved the patient from a lethal issue without any aftereffect.

DISCUSSION

After a review of the literature the authors describe the circumstances of occurrence, the urgent management and the modern treatment of an ICA injury. Along with the progress in neuroradiology, the embolization represents a top grade treatment of this complication. Embolization with stent keeps permeable the ICA axis which represents a major progress in the management.

CONCLUSION

The success of the management of an ICA injury relies on the close collaboration between anesthesist, otorhinolaryngologist surgeon and interventional neuroradiologist. Since 2004, modern techniques of interventional neuroradiology using new stents allow to keep permeable the ICA axis.

Final Results of ECOG1100: A phase I/II study of combined blockade of the ErbB receptor network in patients with HER2- overexpressing metastatic breast cancer (MBC)

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Background: Activation of EGF receptor has been associated with resistance to trastuzumab in breast cancer cell lines. EGFR tyrosine kinase inhibitors inhibit HER2 phosphorylation and synergize with trastuzumab in HER2+ cell lines that co-express EGFR. Methods: Pts with MBC and HER2 overexpression by immunohistochemistry (3+) and/or HER2 gene-amplification by FISH, 0–2 prior chemotherapy regimens for met disease, LVEF 50%, and no prior trastuzumab were treated with trastuzumab 2 mg/kg/wk and gefitinib 250- 500 mg/day until disease progression, unacceptable toxicity or withdrawal of consent. The phase I portion of the trial used a 3+3 design to determine MTD. In the phase II portion of the trial, patients were stratified based upon prior chemotherapy exposure (Group 1= no prior exposure to chemotherapy, Group 2= prior exposure to 1–2 chemotherapy regimens). Response measured using RECIST criteria. The primary endpoint was to increase proportion progression free from 50 to 65% at 6 months in Group 1 and from 50 to 70% at 3 months in Group 2. Results: Phase I: DLT (Grade 3 diarrhea) occurred in 2/3 patients treated at the 500 mg/day dose level of gefitinib in combination with weekly trastuzumab. 0/3 patients treated at the 250 mg/day dose level experienced DLT. This was considered MTD and was the dose selected for the Phase II portion of the trial. Phase II: 36 eligible pts were enrolled. Most patients were ECOG PS of 0 and had visceral organ involvement. Of the patients enrolled in Group 1, one pt achieved a CR, one PR and 7 had SD (≥ 24 weeks). Median time to progression (TTP) was 2.9 months (95% CI, 2.5–4). In Group 2 no responses were observed with a median TTP of 2.5 months (95% CI, 1.5- 2.7). Most common severe toxicities were rash (grade 3, 14%) and diarrhea (grade 3, 30%). No grade 3 cardiac toxicity was encountered. Conclusions: Trastuzumab in combination with gefitinib at doses of 250 mg/day demonstrated an acceptable toxicity profile; however, during planned interim analysis, the TTP did not meet predetermined statistical endpoints required for study continuation. These results do not support the further use of this combination and have implications for other trials using trastuzumab and EGFR TK inhibitors simultaneously.

[Table: see text]

[Gastroduodenal intussusception complicating Menetrier's disease]

The authors report a very rare case of gastroduodenal intussusception complicating Menetrier's disease. This uncommon condition of unknown aetiology is characterized by hyperplasia of the gastric mucosal folds. Computed Tomography (CT) in high resolution mode can be helpful for diagnosis by showing the cerebriform surface of the giant mucosal folds. Filling the gastoduodenal tract with water is useful in non complicated cases.

[Exposition and sensitization to Tyrophagus putrescentiae in a allergic population to Dermatophagoides pteronyssinus in Huelva, Spain]

BACKGROUND

In this work we analyzed the allergological importance of Tyrophagus putrescentiae (Tp) in Huelva (SE Spain). We studied the level of exposition and the grade of sensitization to Tp in a group of patients sensitized to Dermatophagoides pteronyssinus (Dpt). The allergenic cross-reactivity between Dpt and Tp was determined by RAST inhibition.

METHODS AND RESULTS

We analyzed house dust samples from the dwellings of allergic patients with documented Dpt sensitization. Skin test (ST), conjunctival provocation (CP) and/or specific IgE (RAST) to Tp were performed when Tp was identificated in the house dust sample of the patient. Among the 136 dust samples studied, Dpt was the most frequently identified mite species (94.8%) and Tp was found in third position (41.1%) after Glycyphagus domesticus (54.4%). Among the 45 patients studied, 23 (51.1%) presented, at least, two positive tests, 18 (40%) were not sensitized to Tp and 4 (8.8%) showed contradictory results. 26 patients (57.7%) inhabited in urban areas and 19 (42.2%) in rural regions. We determined specific IgE (RAST) to Tp in 25 patients, and the results were positive in 12, with only 7 with values greater than 2 kU/L. No significant correlation were found between IgE-antibody levels to Dpt and Tp. The RAST inhibition studies confirmed the low cross-reactivity between these mites and only in one patient Dpt partially inhibited the IgE-binding to Dpt extract.

CONCLUSIONS

Tp was the second more frequent storage mite in the house dust samples from patients allergic to Dpt in Huelva. However, only half of the exposed patients were sensitized to Tp and the majority inhabited in urban areas. No significant correlation were found between IgE-antibody levels to Dpt and Tp. The RAST inhibition studies confirmed the low cross-reactivity between these mites.

[Bowel obstruction in pregnancy: value of Single Shot Fast Spin Echo MR sequence (SS-FSE)]

Bowel obstruction is a rare but serious complication of pregnancy for both the mother and the developing fetus. The authors report a case of small bowel obstruction in an early pregnant patient. Increasing delay between the onset of symptoms and the diagnosis remains a significant contributing factor to the high morbidity and mortality in the pregnant patient population. So, prompt diagnosis and therapy are essential. Single Shot Fast Spin Echo MR sequence confirmed the presence of bowel obstruction and identified the zone of transition.

[Epithelioid hemangioendothelioma of the foot]

Epithelioid hemangioendothelioma is a rare bone tumor. The authors report a case of a grade 1 multifocal epithelioid hemangioendothelioma of the foot in a 24-year-old man treated by large surgical resection of the two lesions.

Der p 1 and Der f 1, the highly related and major allergens from house dust mites, are differentially affected by a plant cystatin

BACKGROUND

Der p 1 and Der f 1 are highly related allergens from the two main house dust mite species, Dermatophagoides pteronyssinus and Dermatophagoides farinae, respectively. A link between the cysteine proteinase activity of Der p 1 and its allergenicity has recently been demonstrated.

OBJECTIVE

To test the effects of several proteinase inhibitors, mainly a chestnut cystatin (CsC), on the enzymatic activity of Der p 1 and Der f 1, as well as to study the potential acaricide properties of the inhibitors.

METHODS

Inhibition tests were performed using mite extracts, as well as isolated Der p 1 and Der f 1 as targets. Immunodetection after SDS-PAGE and N-terminal amino acid sequencing were used to demonstrate the inactivation of chestnut cystatin by Der p 1. Bioassays including different inhibitors in a semisynthetic diet were performed to evaluate a potential effect on larval survival.

RESULTS

CsC inhibited the crude digestive proteinase activity of D. farinae, but it was not active towards the equivalent enzyme from D. pteronyssinus. This differential behaviour was fully explained by testing CsC against the two purified allergens, Der f 1 and Der p 1; the former was highly susceptible, whereas the latter was not affected. In contrast, other cysteine proteinase inhibitors, such as egg white cystatin and E-64, inhibited the proteinase activity of both mite allergens. Der p 1 inactivated CsC by a specific proteolytic cleavage between Gly 6 and Val 7, thus given rise to a noninhibitory processed protein. Besides the in vitro activity, CsC also showed an in vivo effect on D. farinae, drastically increasing the larval mortality when added to a semisynthetic diet.

CONCLUSION

Der p 1 and Der f 1 behave very differently towards a plant cystatin, thus indicating substantial differences in their proteolytic activity. This fact could be significant with regards to the immunogenic properties of both allergens.

[A case of hepatic Loeffler's syndrome]

INTRODUCTION

During nematode infection transit of the microorganism in the lung may be associated with transient infiltration lesions accompanied by marked eosinophilia. In the invasion stage of the disease maturation and sexual differentiation of schistosomules is restricted to portal vessels. Liver ultrasonography may show concomitant abnormalities.

EXEGESIS

Eosinophilia was diagnosed in a 36-year-old man residing in Central Africa. Clinical examination, chest X-ray and biology were normal. Liver ultrasonography showed numerous hypoechoic lesions, up to 3 cm in diameter. Ultrasonography-directed biopsy demonstrated infiltration of both portal vessels and liver sinusoids, with sometimes microabcesses. No parasite was found in either blood, stool, or rectal biopsy. Immunoelectrophoresis and hemagglutination showed positive bilharziosis serology, whereas serology for other helminthiases was negative. Four months after treatment eosinophilia was still high, liver ultrasonography was normal, and hemagglutination was negative.

CONCLUSION

The transient shistosomules maturation-related liver abnormalities detected by ultrasonography should be differentiated from the laying phase of the disease.

Magnetic susceptibility of Dy-DTPA-BMA to reperfused myocardial infarction in an excised dog heart model: evidence of viable myocardium

OBJECTIVE

To assess the effects of Dy-DTPA-BMA (sprodiamide) on ex-vivo MR imaging of reperfused acute myocardial infarction.

METHODS

Eighteen dogs were subjected to 2-hour coronary artery occlusion followed by 24-hour reperfusion. Dysprosium-chelate (Dy-DTPA-BMA) was injected into 16 dogs. Twenty minutes before their sacrifice. Two dogs did not receive the contrast medium and were used as controls. Excised hearts were imaged on T2-weighted spin-echo sequence (T2W SE) and T2*-weighted gradient recalled echo sequence (T2*W GRE), then sectioned and double-perfused for planimetric comparison.

RESULTS

Dy-DTPA-BMA induced myocardial signal loss was detected on T2W SE and on T2*W GRE images. The signal loss was observed at the subendocardial location of the myocardial wall inducing an apparent enlargement of the left ventricle cavity and a thinning appearance of the anterior myocardial wall.

CONCLUSIONS

Myocyte necrosis diminishes the potency of dysprosium to cause MR imaging signal intensity loss in reperfused myocardial infarction. Pre-infarcted myocardium with potentially reversible viability may be responsible for the effect of the contrast medium.

Predictive value of regional left ventricular circumferential shortening in jeopardized myocardium. A two-dimensional SPAMM cine-MRI study in a canine model

OBJECTIVE

To determine whether myocardial circumferential shortening assessed in the different myocardial layers by SPAMM cine-MRI may help to discriminate between various degrees of myocardial injury in reperfused myocardium.

METHODS

Dogs underwent 90 minutes of coronary occlusion and 24 hours of reperfusion. Using a 1.5 T whole-body MR scanner, SPAMM cine-MRI images were acquired before and 24 hours after surgery on the short axis plan of the left ventricle and analyzed to evaluate the mean myocardial circumferential shortening (% MCS) in the different layers. Based on the residual blood flow, animals were assigned to group I (residual flow < 22.5%) or group II (residual flow > 22.5%).

RESULTS

Dogs in group I developed larger infarctions (25.3% +/- 14.6 of the area at risk, n = 5) compared with those in group II (5.81% +/- 1.1, n = 7, P < 0.05). In the jeopardized zone, the % MCS of the subendocardium decreased more significantly in group I (-0.03% +/- 3.7 to 2.2% +/- 5.2) compared with group II (14.7% +/- 1.5 to 18.4% +/- 1.4).

CONCLUSIONS

SPAMM cine-MRI is a fast and noninvasive means of measuring % MCS. The MR measurement of this parameter in the subendocardial layer appears quite accurate in describing the degree of damage in reperfused myocardium.

Synthesis and cytotoxic activity of N-(2-pyridylsulfenyl)urea derivatives. A new class of potential antineoplastic agents

Starting from a 3D-model for the antineoplastic activity of diarylsulfonylureas several new features were proposed and tested. Both types of assayed compounds, the N-(2-pyridylsulfonyl)urea and N-(2-pyridylsulfenyl)urea derivatives, inhibited by 50% the growth of the CCRF-CEM cell line at a dosage near to 1 microM. The N -(2-pyrimidinyl) derivative of the sulfenylurea 6c showed a better profile against HT-29, K-562 and HTB-54 tumor cell lines than the corresponding sulfonylurea 6b. Structural modifications on aryl systems affected differently to the cytotoxic activity shown by the compounds against each cell line.

[Idiopathic chronic eosinophilic pneumonia]

Idiopathic chronic eosinophilic pneumonia is a rare disease first described by Carrington 30 years ago. The cause is unknown. As illustrated by the case described in this report, most cases occur in asthmatic patients in the fifth decade of life. Cardinal features are respiratory symptoms, altered general status, laboratory evidence of inflammation, blood eosinophilia in most cases, and x-ray images showing the presence of infiltrates in both lungs. Diagnosis can be confirmed by detection of eosinophils in broncho-alveolar lavage fluid. Extrapulmonary involvement is uncommon and is suggestive of Churg and Strauss syndrome. In atypical cases, diagnosis requires histological study demonstrating infiltration of interstitial tissue and alveolar spaces. Differential diagnosis can be difficult since several disorders identified within the last 10 years are nosologically similar, e.g. acute eosinophilic pneumonia. In many cases, diagnosis is based on response to corticosteroid treatment which is highly effective on idiopathic chronic eosinophilic pneumonia. Frequent recurrence leads to corticosteroid dependence in 20 to 30% of cases.

[Soft tissue eosinophilic granuloma or Kimura's disease: a case report]

Soft tissue eosinophilic granuloma or Kimura's disease is a chronic inflammatory disorder of unknown etiology. It is endemic in the Far East but can occur sporadically in other populations especially Middle Eastern peoples as illustrated by the present case involving a 55-year-old man. Examination 8 years after an initial episode revealed masses in the cheek and submaxillary regions with hypereosinophilia and characteristic histological findings. The usual clinical presentation of Kimura's disease includes subcutaneous nodules with lymph node involvement or presence of tumor in the salivary glands. These clinicopathological findings require differential diagnosis with Hodgkin's lymphoma, dermopathic lymphoma, or Castelman's disease. However, the most difficult distinction involves angiolymphoid hyperplasia with eosinophilia. Final diagnosis requires anatomopathological study. The most frequently encountered histological criteria are preservation of node structure, highly developed germinal centers, eosinophilic infiltration, and presence of numerous postcapillary veinlets. Prognosis is favorable but multiple relapses are possible. Corticosteroid therapy is usually effective but radiation treatment may be necessary in patients with recurrent disease.

Myocardial "low reflow" assessed by Dy-DTPA-BMA-enhanced first-pass MR imaging in a dog model

The aim of this study was to determine whether the use of a magnetic resonance (MR) susceptibility contrast medium, dysprosium diethylenetriamine pentaacetic acid-bismethylamide (Dy DTPA-BMA; Sprodiamide), may characterize myocardial perfusion abnormalities in a dog model of 90 minutes of coronary occlusion followed by 24 hours of reperfusion (no-reflow phenomenon installed). First-pass MR imaging after an intravenous bolus administration of the contrast agent was performed at the end of reperfusion. Signal intensity analysis on MR imaging, planimetry of pathological data, and blood flow determination were obtained by reference methods for comparison. Dogs were separated into two groups according to the level of collateral blood flow level (group I, <22.5 % of the flow in the non-ischemic zone; group II, >22.5 % of the flow in the non-ischemic zone). Signal intensity-time curves in the ischemic and non-ischemic left ventricle walls were extracted. Mean collateral blood flow was lower during occlusion in group I (9.8 +/- 5.4%, n = 5) than in group II (38 +/- 12.5%, n = 7, P < 0.05). Mean infarct size (expressed as a percentage of the area at risk) was significantly larger in group I (low collateral blood flow; 25.3 +/- 14.6%) than in group II (high collateral blood flow; 5.8 +/- 1.1%, P < 0.05). After rapid injection, a transient decrease of signal intensity induced by Dy DTPA-BMA was observed in both remote and ischemic myocardium but more markedly in remote normally perfused myocardium. Hence, during the transit of a susceptibility-type contrast agent, ischemic myocardium after ischemia and reperfusion appeared as a relative high signal intensity area. First-pass MR imaging with susceptibility contrast agent demonstrated the no- or low-reflow phenomenon. However, the behavior of the myocardial signal intensity-time-related curves did not allow distinction between the two groups of dogs.

[Prevalence of intestinal helminthiasis in 100 municipalities in Venezuela (1989-1992)]

A total of 113,254 individuals from 100 venezuelan municipalities were studied by mean of Kato-Katz coprological examination and the geohelminth prevalences were established. The national prevalences of T. trichiura, A. lumbricoides and Anquilostomideos were 32.6%, 26.9% and 5.6% respectively+. For T. trichiura the highest values were obtained for the following municipalities: Arévalo González (54.6%) in Miranda state, Urama (76.9%) in Carabobo state and Punta de Piedra (78.4%) in Sucre state. For A. lumbricoides the highest values were determined in Punta de Piedra (63%), Tunapuy (61.9%) in Sucre state and Arévalo González (62.7%) in Miranda state. For hookworm the highest values were detected in El Amparo (39.5%) and San Camilo (35.9%) in the state of Apure. In relation to the age, the highest prevalence of Ascariosis and Trichuriosis were determined in pre-school and school children and for hookworm in adolescents and adults. A high variability between the municipalities belonging to the same state for the three geohelminths was observed.

The last fifteen years of schistosomiasis in Venezuela: features and evolution

Control of schistosomiasis in Venezuela has been a topic of major interest and controversy among the metaxenic parasitosis. A small area of transmission of approximately 15,000 km2 was thought to be eradicated some years ago. However, some epidemiological characteristics of our transmission area have limited the success on the way toward eradication. Since 1945, when the Schistosomiasis Control Program started, the prevalence in the endemic area has decreased from 14% in 1943 to 1.4% in 1996. Until 1982, the surveillance of active cases was based on massive stool examination. Since then, the Schistosomiasis Research Group (SRG) recommended the additional use of serologic tests in the Control Program and the selective or massive chemotherapy depending on serological and parasitological prevalence of each community. At present, the real prevalence is underestimated due to the fact that approximately 80% of the individuals eliminate less than 100 eggs/g of feces. Those persons could be responsible for the maintenance of the foci going on and therefore limiting the impact of the control measures. Efforts of the SRG are being oriented toward improvement of immunodiagnostic tests by using defined antigens (enzymes) and chemically synthesized peptides, derived from relevant molecules of the parasite, either for antibodies or antigens search. On the other hand, introduction of snail competitors has been a biological weapon in the control of the intermediate host in certain areas. However, the recent reinfestation of water courses by Biomphalaria glabrata, the increased prevalence in some areas, together with important administrative changes at the Control Program of the Minister of Health, have arisen new questions and doubts, challenging the eradication strategy proposed during the last decade.

[Osteoarticular involvement in parasitic diseases: bone mycetoma]

Mycetoma remains a common pathology in tropical areas. Diagnosis, based on mycology and pathology is still frequently late and treatment often leaves severe functional disorders. Medical imaging is indispensable to evaluate disease spread to bone tissue. Plain radiograms usually show cortical erosion, defects with sclerosing margins, and bone thickening. CT is the most sensitive technique to detect bony involvement. CT and MR imaging, when available, are the most accurate techniques for determining disease extension in both bones and soft tissues.

[Osteoarticular involvement in parasitic diseases: bone treponematosis]

Bone and joint localizations of treponematosis vary greatly although there are many common features. Osteal and periosteal lesions are common. We report radiographic descriptions of bone and joint treponematosis, which must not go unrecognized due to the increasing incidence of these diseases.

[Osteoarticular involvement in parasitic diseases: bone echinococcosis]

Hydatid disease is the most common human disease caused by helminths, but primary skeletal involvement is uncommon. Diagnosis is usually obtained late after considerable extension, half of which concerns the spine. The dissemination mode leads to local malignancy with severe prognosis. Medical imaging is essential. Plain x-ray findings are polymorphous and nonspecific, but computed tomography and magnetic resonance imaging are particularly useful for exhaustive pretherapeutic assessment of extension and for patient follow-up.

[Relationships in the prevalence of geohelminth infections in humans from Venezuela]

By means of Kato-Katz technique 113,254 coprological samples of the human population belonging to 100 counties from Venezuela were analyzed. It was determined the following prevalences: Ascaris lumbricoides 26.8%, Trichuris trichiura 32.7% and hookworm 5.6%. It was found a strong correlation between A. lumbricoides and T. trichiura infection (p < 0.001), a significant correlation between T. trichiura and hookworm (p < 0.5) and no correlation between A. lumbricoides and hookworm.

[Demonstration by x-ray computed tomography of renal involvement caused by NSAID poisoning]

We describe the contribution of computed tomography in the determination of the renal damage after using tiaprofenic acid. Computed tomography realized six hours after injection of contrast medium revealed corticomedullary enhancement secondary to vascular and tubular stasis. This stasis is compatible with interstitial edema in relation with usually reversible lesions of tubulo-interstitial nephritis induced by of nonsteroidal anti-inflammatory drugs.