Paper-Based Vertical Flow Immunoassay for the Point-of-Care Multiplex Detection of Radiation Dosimetry Genes

In a nuclear or radiological incident, first responders must quickly and accurately measure radiation exposure among civilians as medical countermeasures are radiation dose-dependent and time-sensitive. Although several approaches have been explored to measure absorbed radiation dose, there is an important need to develop point-of-care (POC) bioassay devices that can be used immediately to triage thousands of individuals potentially exposed to radiation. Here we present a proof-of-concept study showing the use of a paper-based vertical flow immunoassay (VFI) to detect radiation dosimetry genes. Using labeled primers during amplification and a multiplex membrane, our results showed that the nucleic acid VFI can simultaneously detect two biodosimetry genes, CDKN1A and DDB2, as well as one housekeeping gene MRPS5. The assay demonstrated good linearity and precision with an inter- and intra-assay coefficient of variance <20% and <10%, respectively. Moreover, the assay showed its ability to discriminate non-irradiated controls (0 Gy) from irradiated samples (1 + 2 Gy) with an overall sensitivity of 62.5% and specificity of 100% (AUC = 0.8672, 95% CI: 0.723-1.000; p = 0.004). Interestingly, the gene combination also showed a dose-dependent response for 0, 1, and 2 Gy, similar to data obtained by real-time PCR benchmark. These preliminary results suggest that a VFI platform can be used to detect simultaneously multiple genes that can be then quantified, thus offering a new approach for a POC biodosimetry assay that could be rapidly deployed on-site to test a large population and help triage and medical management after radiological event.

RENEB Inter-Laboratory Comparison 2021: Inter-Assay Comparison of Eight Dosimetry Assays

Tools for radiation exposure reconstruction are required to support the medical management of radiation victims in radiological or nuclear incidents. Different biological and physical dosimetry assays can be used for various exposure scenarios to estimate the dose of ionizing radiation a person has absorbed. Regular validation of the techniques through inter-laboratory comparisons (ILC) is essential to guarantee high quality results. In the current RENEB inter-laboratory comparison, the performance quality of established cytogenetic assays [dicentric chromosome assay (DCA), cytokinesis-block micronucleus assay (CBMN), stable chromosomal translocation assay (FISH) and premature chromosome condensation assay (PCC)] was tested in comparison to molecular biological assays [gamma-H2AX foci (gH2AX), gene expression (GE)] and physical dosimetry-based assays [electron paramagnetic resonance (EPR), optically or thermally stimulated luminescence (LUM)]. Three blinded coded samples (e.g., blood, enamel or mobiles) were exposed to 0, 1.2 or 3.5 Gy X-ray reference doses (240 kVp, 1 Gy/min). These doses roughly correspond to clinically relevant groups of unexposed to low exposed (0-1 Gy), moderately exposed (1-2 Gy, no severe acute health effects expected) and highly exposed individuals (>2 Gy, requiring early intensive medical care). In the frame of the current RENEB inter-laboratory comparison, samples were sent to 86 specialized teams in 46 organizations from 27 nations for dose estimation and identification of three clinically relevant groups. The time for sending early crude reports and more precise reports was documented for each laboratory and assay where possible. The quality of dose estimates was analyzed with three different levels of granularity, 1. by calculating the frequency of correctly reported clinically relevant dose categories, 2. by determining the number of dose estimates within the uncertainty intervals recommended for triage dosimetry (±0.5 Gy or ±1.0 Gy for doses <2.5 Gy or >2.5 Gy), and 3. by calculating the absolute difference (AD) of estimated doses relative to the reference doses. In total, 554 dose estimates were submitted within the 6-week period given before the exercise was closed. For samples processed with the highest priority, earliest dose estimates/categories were reported within 5-10 h of receipt for GE, gH2AX, LUM, EPR, 2-3 days for DCA, CBMN and within 6-7 days for the FISH assay. For the unirradiated control sample, the categorization in the correct clinically relevant group (0-1 Gy) as well as the allocation to the triage uncertainty interval was, with the exception of a few outliers, successfully performed for all assays. For the 3.5 Gy sample the percentage of correct classifications to the clinically relevant group (≥2 Gy) was between 89-100% for all assays, with the exception of gH2AX. For the 1.2 Gy sample, an exact allocation to the clinically relevant group was more difficult and 0-50% or 0-48% of the estimates were wrongly classified into the lowest or highest dose categories, respectively. For the irradiated samples, the correct allocation to the triage uncertainty intervals varied considerably between assays for the 1.2 Gy (29-76%) and 3.5 Gy (17-100%) samples. While a systematic shift towards higher doses was observed for the cytogenetic-based assays, extreme outliers exceeding the reference doses 2-6 fold were observed for EPR, FISH and GE assays. These outliers were related to a particular material examined (tooth enamel for EPR assay, reported as kerma in enamel, but when converted into the proper quantity, i.e. to kerma in air, expected dose estimates could be recalculated in most cases), the level of experience of the teams (FISH) and methodological uncertainties (GE). This was the first RENEB ILC where everything, from blood sampling to irradiation and shipment of the samples, was organized and realized at the same institution, for several biological and physical retrospective dosimetry assays. Almost all assays appeared comparably applicable for the identification of unexposed and highly exposed individuals and the allocation of medical relevant groups, with the latter requiring medical support for the acute radiation scenario simulated in this exercise. However, extreme outliers or a systematic shift of dose estimates have been observed for some assays. Possible reasons will be discussed in the assay specific papers of this special issue. In summary, this ILC clearly demonstrates the need to conduct regular exercises to identify research needs, but also to identify technical problems and to optimize the design of future ILCs.

RENEB Inter-Laboratory Comparison 2021: The Gene Expression Assay

Early and high-throughput individual dose estimates are essential following large-scale radiation exposure events. In the context of the Running the European Network for Biodosimetry and Physical Dosimetry (RENEB) 2021 exercise, gene expression assays were conducted and their corresponding performance for dose-assessment is presented in this publication. Three blinded, coded whole blood samples from healthy donors were exposed to 0, 1.2 and 3.5 Gy X-ray doses (240 kVp, 1 Gy/min) using the X-ray source Yxlon. These exposures correspond to clinically relevant groups of unexposed, low dose (no severe acute health effects expected) and high dose exposed individuals (requiring early intensive medical health care). Samples were sent to eight teams for dose estimation and identification of clinically relevant groups. For quantitative reverse transcription polymerase chain reaction (qRT-PCR) and microarray analyses, samples were lysed, stored at 20°C and shipped on wet ice. RNA isolations and assays were run in each laboratory according to locally established protocols. The time-to-result for both rough early and more precise later reports has been documented where possible. Accuracy of dose estimates was calculated as the difference between estimated and reference doses for all doses (summed absolute difference, SAD) and by determining the number of correctly reported dose estimates that were defined as ±0.5 Gy for reference doses <2.5 Gy and ±1.0 Gy for reference doses >3 Gy, as recommended for triage dosimetry. We also examined the allocation of dose estimates to clinically/diagnostically relevant exposure groups. Altogether, 105 dose estimates were reported by the eight teams, and the earliest report times on dose categories and estimates were 5 h and 9 h, respectively. The coefficient of variation for 85% of all 436 qRT-PCR measurements did not exceed 10%. One team reported dose estimates that systematically deviated several-fold from reported dose estimates, and these outliers were excluded from further analysis. Teams employing a combination of several genes generated about two-times lower median SADs (0.8 Gy) compared to dose estimates based on single genes only (1.7 Gy). When considering the uncertainty intervals for triage dosimetry, dose estimates of all teams together were correctly reported in 100% of the 0 Gy, 50% of the 1.2 Gy and 50% of the 3.5 Gy exposed samples. The order of dose estimates (from lowest to highest) corresponding to three dose categories (unexposed, low dose and highest exposure) were correctly reported by all teams and all chosen genes or gene combinations. Furthermore, if teams reported no exposure or an exposure >3.5 Gy, it was always correctly allocated to the unexposed and the highly exposed group, while low exposed (1.2 Gy) samples sometimes could not be discriminated from highly (3.5 Gy) exposed samples. All teams used FDXR and 78.1% of correct dose estimates used FDXR as one of the predictors. Still, the accuracy of reported dose estimates based on FDXR differed considerably among teams with one team's SAD (0.5 Gy) being comparable to the dose accuracy employing a combination of genes. Using the workflow of this reference team, we performed additional experiments after the exercise on residual RNA and cDNA sent by six teams to the reference team. All samples were processed similarly with the intention to improve the accuracy of dose estimates when employing the same workflow. Re-evaluated dose estimates improved for half of the samples and worsened for the others. In conclusion, this inter-laboratory comparison exercise enabled (1) identification of technical problems and corrections in preparations for future events, (2) confirmed the early and high-throughput capabilities of gene expression, (3) emphasized different biodosimetry approaches using either only FDXR or a gene combination, (4) indicated some improvements in dose estimation with FDXR when employing a similar methodology, which requires further research for the final conclusion and (5) underlined the applicability of gene expression for identification of unexposed and highly exposed samples, supporting medical management in radiological or nuclear scenarios.

Decellularized Spinach Biomaterials Support Physiologically Relevant Mechanical Cyclic Strain and Prompt a Stretch-Induced Cellular Response

Recently, decellularized plant biomaterials have been explored for their use as tissue engineered substitutes. Herein, we expanded upon the investigation of the mechanical properties of these materials to explore their elasticity as many anatomical areas of the body require biomechanical dynamism. We first constructed a device to secure the scaffold and induce a strain within the physiological range of the normal human adult lung during breathing (12-20 movements/min; 10-20% elongation). Results showed that decellularized spinach leaves can support cyclic strain for 24 h and displayed heterogeneous local strain values (7.76-15.88%) as well as a Poisson's ratio (0.12) similar to that of mammalian lungs (10.67-19.67%; 0.01), as opposed to an incompressible homogeneous standard polymer (such as PDMS (10.85-12.71%; 0.4)). Imaging and mechanical testing showed that the vegetal scaffold exhibited strain hardening but maintained its structural architecture and water retention capacity, suggesting an unaltered porosity. Interestingly, we also showed that cells seeded on the scaffold can also sense the mechanical strain as demonstrated by a nuclear reorientation perpendicular to strain direction (63.3° compared to 41.2° for nonstretched cells), a nuclear location of YAP and increased expression of YAP target genes, a high cytoplasmic calcium level, and an elevated expression level of collagen genes (COL1A1, COL3A1, COL4A1, and COL6A) with an increased collagen secretion at the protein level. Taken together, these data demonstrated that decellularized plant leaf tissues have an inherent elastic property similar to that found in the mammalian system to which cells can sense and respond.

Effect of mechanical forces on cellular response to radiation

While the cellular interactions and biochemical signaling has been investigated for long and showed to play a major role in the cell's fate, it is now also evident that mechanical forces continuously applied to the cells in their microenvironment are as important for tissue homeostasis. Mechanical cues are emerging as key regulators of cellular drug response and we aimed to demonstrate in this review that such effects should also be considered vital for the cellular response to radiation. In order to explore the mechanobiology of the radiation response, we reviewed the main mechanoreceptors and transducers, including integrin-mediated adhesion, YAP/TAZ pathways, Wnt/β-catenin signaling, ion channels and G protein-coupled receptors and showed their implication in the modulation of cellular radiosensitivity. We then discussed the current studies that investigated a direct effect of mechanical stress, including extracellular matrix stiffness, shear stress and mechanical strain, on radiation response of cancer and normal cells and showed through preliminary results that such stress effectively can alter cell response after irradiation. However, we also highlighted the limitations of these studies and emphasized some of the contradictory data, demonstrating that the effect of mechanical cues could involve complex interactions and potential crosstalk with numerous cellular processes also affected by irradiation. Overall, mechanical forces alter radiation response and although additional studies are required to deeply understand the underlying mechanisms, these effects should not be neglected in radiation research as they could reveal new fundamental knowledge for predicting radiosensitivity or understanding resistance to radiotherapy.

Abstract 5696: Effect of extracellular matrix stiffness on cancer cells radiation response

Over the past decade, it has become clear that the mechanical cues of extracellular matrix (ECM) are a major regulator of the cancer biology. In particular, ECM stiffness has shown an important role in chemoresistance modulation. However, despite the central role of radiotherapy in cancer management, little is known about the effect of ECM stiffness on cancer cells radiation response. In this study, we used polyacrylamide collagen-coated hydrogel model to reproduce a soft (0.7 kPa) and a stiff (70 kPa) matrix. The model was validated by atomic force microscopy force spectroscopy and biological analyses through cellular morphology, proliferation and YAP/TAZ mechanotransduction pathway that all confirmed the accuracy of our model. Then, lung cancer cells seeded on both soft and stiff hydrogels were irradiated, and the level of DNA damages were compared between the two conditions. First, alkaline comet assay revealed the total amount of DNA damages were higher in cells grown on a rigid ECM at 1 h post-irradiation than cells seeded on a soft matrix. Second, γH2AX/53BP1 foci assay showed that the number of DNA double strand breaks were also higher in cells grown on a rigid environment. However, the level of DNA damage was identical at 24 h post-irradiation for both stiffness, suggesting that a more efficient DNA damage repair response could take place for cells seeded in stiff matrix. In order to explain these observations, analyses on chromatin structure and nucleus shape were then performed. Data showed that cells cultured on stiff matrix displayed a larger nucleus, less condensed chromatin, and a decreased expression level of class I HDACs genes. Moreover, it was found that the level of total reactive oxygen species (ROS) and superoxide ion was also higher in cells grown on a rigid environment 24 h post-irradiation. Altogether these data suggest that a high stiffness may increase early DNA damages after irradiation, partially by remodeling chromatin that could expose DNA to radiation-induced genotoxic agents such as ROS. Additional investigations are required to understand better the mechanisms that could explain such differences, but these preliminary data highlighted the potential role of mechanical stress in cellular radiation response and paved the way to new therapeutic target for radiotherapy management.

Citation Format: Jerome Lacombe, Melinda Muccio, Frederic Zenhausern. Effect of extracellular matrix stiffness on cancer cells radiation response [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5696.

The Emerging Role of Decellularized Plant-Based Scaffolds as a New Biomaterial

The decellularization of plant-based biomaterials to generate tissue-engineered substitutes or in vitro cellular models has significantly increased in recent years. These vegetal tissues can be sourced from plant leaves and stems or fruits and vegetables, making them a low-cost, accessible, and sustainable resource from which to generate three-dimensional scaffolds. Each construct is distinct, representing a wide range of architectural and mechanical properties as well as innate vasculature networks. Based on the rapid rise in interest, this review aims to detail the current state of the art and presents the future challenges and perspectives of these unique biomaterials. First, we consider the different existing decellularization techniques, including chemical, detergent-free, enzymatic, and supercritical fluid approaches that are used to generate such scaffolds and examine how these protocols can be selected based on plant cellularity. We next examine strategies for cell seeding onto the plant-derived constructs and the importance of the different functionalization methods used to assist in cell adhesion and promote cell viability. Finally, we discuss how their structural features, such as inherent vasculature, porosity, morphology, and mechanical properties (i.e., stiffness, elasticity, etc.) position plant-based scaffolds as a unique biomaterial and drive their use for specific downstream applications. The main challenges in the field are presented throughout the discussion, and future directions are proposed to help improve the development and use of vegetal constructs in biomedical research.

Evaluation of supercritical CO2 sterilization efficacy for sanitizing personal protective equipment from the coronavirus SARS-CoV-2

The purpose of this research is to evaluate the supercritical carbon dioxide (scCO₂) sterilization-based NovaClean process for decontamination and reprocessing of personal protective equipment (PPE) such as surgical masks, cloth masks, and N95 respirators. Preliminarily, Bacillus atrophaeus were inoculated into different environments (dry, hydrated, and saliva) to imitate coughing and sneezing and serve as a "worst-case" regarding challenged PPE. The inactivation of the microbes by scCO₂ sterilization with NovaKill or H₂O₂ sterilant was investigated as a function of exposure times ranging from 5 to 90 min with a goal of elucidating possible mechanisms. Also, human coronavirus SARS-CoV-2 and HCoV-NL63 were inoculated on the respirator material, and viral activity was determined post-treatment. Moreover, we investigated the reprocessing ability of scCO₂-based decontamination using wettability testing and surface mapping. Different inactivation mechanisms have been identified in scCO₂ sanitization, such as membrane damage, germination defect, and dipicolinic acid leaks. Moreover, the viral sanitization results showed a complete inactivation of both coronavirus HCoV-NL63 and SARS-CoV-2. We did not observe changes in PPE morphology, topographical structure, or material integrity, and in accordance with the WHO recommendation, maintained wettability post-processing. These experiments establish a foundational understanding of critical elements for the decontamination and reuse of PPE in any setting and provide a direction for future research in the field.

Abstract 3068: Everolimus mediated Radioprotection on surrounding healthy tissue in glioblastoma microbrain models

Background: After surgical resection, ionizing radiation alone or in combination with chemotherapy is the main treatment modality for brain tumors including glioblastoma (GBM). Although the effect of radiation-induced (RI) damage improves the patient survival ratio, injury to the neural stem and progenitor cell (NSPC) compartments and damage to NSPC populations is hypothesized to be central to the pathogenesis of RI cognitive decline in the patients. Studies on sensitivity of neural cell populations to radiation have shown that mature neurons and astrocytes have substantial radio resistance; in contrast, NSPC are highly sensitive to radiation, as exposure induces DNA double-strand breaks that when unrepaired can lead to cell death. Therefore, protection of NPCs is an important countermeasure against radiotherapy in normal tissues. Rapamycin, a small molecule inhibitor of mammalian target of rapamycin (mTOR), has been shown to exert a profoundly protective effect on epithelial and hematopoietic stem cells upon exposure to radiation therapy. Recently, several pharmacokinetically improved rapamycin analogs have secured FDA approval. In this study we investigate the potential of Everolimus as radio-protector for NSPCs in a GBM environment.

Materials and Methods: NSPCs generated from healthy donors and GBM cells were treated with different doses of Everolimus 24 h before and after a single dose 4 Gy irradiation. Survival was monitored using Cell Titer Glo assay. Western Blots, qPCR and immunofluorescence were used to assess mTOR pathway activation and NPC differentiation in 2D and 3D culture. Co-culture of NSPCs and GFP-tagged GBM cells were treated with Everolimus and irradiated with subsequent followup by confocal imaging to check the relative survival of these cells.

Results: Low doses of Everolimus restored survival and proliferation of irradiated NSPCs, while GBM cells remained radiosensitive. qPCR analysis of Nestin, SOX2 and FOXG1 revealed that NSPCs maintained their stemness after treatment. MAP2 and βIII tubulin analysis demonstrated that irradiated NSPCs were able to differentiate to neurons upon treatment. Everolimus treatment also reduced γH2A and phospho-PP2A levels and promoted phosphorylation of Akt suggesting that mTOR inhibition with Everolimus could activate DNA repair in irradiated NPCs.

Conclusions: Our findings suggest that pretreatment with low-dose Everolimus may protect NSPCs from radiation induced injuries after radiation therapy, while maintaining radiation sensitivity to GBM cells. This study suggests low-dose Everolimus as a potential radio-protector for clinical treatment of glioblastoma and other brain malignancies.

Citation Format: Tithi Ghosh Halder, Ryan Rodriguez del Villar, Jerome Lacombe, Kevin Drenner, Serina Ng, Trason Thode, Alexis Weston, Mohan Kaadige, Raffaella Soldi, Sunil Sharma. Everolimus mediated Radioprotection on surrounding healthy tissue in glioblastoma microbrain models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 3068.

Bcor Immunohistochemistry, And Not SATB2, Is A Sensitive And Specific Diagnostic Biomarker For Cns Tumors With BCOR Internal Tandem Duplication

Central nervous system (CNS) tumors with the BCOR (BCL6 Corepressor) internal tandem duplication (ITD) were recently isolated by a DNA-methylation profile from a series of primitive neuroectodermal tumors [1]. They are mainly characterized by a recurrent BCOR ITD and express BCOR by immunohistochemistry (IHC) [2]. In rare cases, they present an EP300-BCOR fusion inducing the absence of expression of BCOR by IHC [3]. In soft tissue and kidney tumors with different types of BCOR alterations, SATB2 has been considered a diagnostic hallmark and BCOR IHC is not highly specific in some other contexts (soft tissue and uterine tumors) [4]. In a recent paper, SATB2 immunoexpression has been evidenced in one CNS-tumor with proven BCOR ITD [5]. The aim of our study was to evaluate the sensitivity and specificity of the BCOR and SATB2 immunostainings in a large cohort of pediatric CNS tumors.

Supercritical carbon dioxide decellularization of plant material to generate 3D biocompatible scaffolds

The use of plant-based biomaterials for tissue engineering has recently generated interest as plant decellularization produces biocompatible scaffolds which can be repopulated with human cells. The predominant approach for vegetal decellularization remains serial chemical processing. However, this technique is time-consuming and requires harsh compounds which damage the resulting scaffolds. The current study presents an alternative solution using supercritical carbon dioxide (scCO2). Protocols testing various solvents were assessed and results found that scCO2 in combination with 2% peracetic acid decellularized plant material in less than 4 h, while preserving plant microarchitecture and branching vascular network. The biophysical and biochemical cues of the scCO2 decellularized spinach leaf scaffolds were then compared to chemically generated scaffolds. Data showed that the scaffolds had a similar Young's modulus, suggesting identical stiffness, and revealed that they contained the same elements, yet displayed disparate biochemical signatures as assessed by Fourier-transform infrared spectroscopy (FTIR). Finally, human fibroblast cells seeded on the spinach leaf surface were attached and alive after 14 days, demonstrating the biocompatibility of the scCO2 decellularized scaffolds. Thus, scCO2 was found to be an efficient method for plant material decellularization, scaffold structure preservation and recellularization with human cells, while performed in less time (36 h) than the standard chemical approach (170 h).

Plant-Based Scaffolds Modify Cellular Response to Drug and Radiation Exposure Compared to Standard Cell Culture Models

Plant-based scaffolds present many advantages over a variety of biomaterials. Recent studies explored their potential to be repopulated with human cells and thus highlight a growing interest for their use in tissue engineering or for biomedical applications. However, it is still unclear if these in vitro plant-based scaffolds can modify cell phenotype or affect cellular response to external stimuli. Here, we report the characterization of the mechano-regulation of melanoma SK-MEL-28 and prostate PC3 cells seeded on decellularized spinach leaves scaffolds, compared to cells deposited on standard rigid cell culture substrate, as well as their response to drug and radiation treatment. The results showed that YAP/TAZ signaling was downregulated, cellular morphology altered and proliferation rate decreased when cells were cultured on leaf scaffold. Interestingly, cell culture on vegetal scaffold also affected cellular response to external stress. Thus, SK-MEL-28 cells phenotype is modified leading to a decrease in MITF activity and drug resistance, while PC3 cells showed altered gene expression and radiation response. These findings shed lights on the decellularization of vegetal materials to provide substrates that can be repopulated with human cells to better reproduce a soft tissue microenvironment. However, these complex scaffolds mediate changes in cell behavior and in order to exploit the capability of matching physical properties of the various plant scaffolds to diverse physiological functionalities of cells and human tissue constructs, additional studies are required to better characterize physical and biochemical cell-substrate interactions.

Withanolide D Enhances Radiosensitivity of Human Cancer Cells by Inhibiting DNA Damage Non-homologous End Joining Repair Pathway

Along with surgery and chemotherapy, radiation therapy (RT) is an important modality in cancer treatment, and the development of radiosensitizers is a current key challenge in radiobiology to maximize RT efficiency. In this study, the radiosensitizing effect of a natural compound from the withanolide family, withanolide D (WD), was assessed. Clonogenic assays showed that a 1 h WD pretreatment (0.7 μM) before irradiation decreased the surviving fraction of several cancer cell lines. To determine the mechanisms by which WD achieved its radiosensitizing effect, we then assessed whether WD could promote radiation-induced DNA damages and inhibit double-strand breaks (DSBs) repair in SKOV3 cells. Comet and γH2AX/53BP1 foci formation assays confirmed that DSBs were higher between 1 and 24 h after 2 Gy-irradiation in WD-treated cells compared to vehicle-treated cells, suggesting that WD induced the persistence of radiation-induced DNA damages. Immunoblotting was then performed to investigate protein expression involved in DNA repair pathways. Interestingly, DNA-PKc, ATM, and their phosphorylated forms appeared to be inhibited 24 h post-irradiation in WD-treated samples. XRCC4 expression was also down-regulated while RAD51 expression did not change compared to vehicle-treated cells suggesting that only non-homologous end joining (NHEJ) pathways was inhibited by WD. Mitotic catastrophe (MC) was then investigated in SKOV3, a p53-deficient cell line, to assess the consequence of such inhibition. MC was induced after irradiation and was predominant in WD-treated samples as shown by the few numbers of cells pursuing into anaphase and the increased amount of bipolar metaphasic cells. Together, these data demonstrated that WD could be a promising radiosensitizer candidate for RT by inhibiting NHEJ pathway and promoting MC. Additional studies are required to better understand its efficiency and mechanism of action in more relevant clinical models.

Development of an integrated fingerstick blood self-collection device for radiation countermeasures

We report the development of system for packaging critical components of the traditional collection kit to make an integrated fingerstick blood collector for self-collecting blood samples of 100 μl or more for radiation countermeasures. A miniaturized vacuum tube system (VacuStor system) has been developed to facilitate liquid reagent storage, simple operation and reduced sample contamination. Vacuum shelf life of the VacuStor tube has been analyzed by the ideal gas law and gas permeation theory, and multiple ways to extend vacuum shelf life beyond one year have been demonstrated, including low temperature storage, Parylene barrier coating and container vacuum bag sealing. Self-collection was also demonstrated by healthy donors without any previous fingerstick collection experience. The collected blood samples showed similar behavior in terms of gene expression and cytogenetic biodosimetry assays comparing to the traditionally collected samples. The integrated collector may alleviate the sample collection bottleneck for radiation countermeasures following a large-scale nuclear event, and may be useful in other applications with its self-collection and liquid reagent sample preprocessing capabilities.

Fabric Phase Sorptive Extraction-A Metabolomic Preprocessing Approach for Ionizing Radiation Exposure Assessment

The modern application of mass spectrometry-based metabolomics to the field of radiation assessment and biodosimetry has allowed for the development of prompt biomarker screenings for radiation exposure. Our previous work on radiation assessment, in easily accessible biofluids (such as urine, blood, saliva), has revealed unique metabolic perturbations in response to radiation quality, dose, and dose rate. Nevertheless, the employment of swift injury assessment in the case of a radiological disaster still remains a challenge as current sample processing can be time consuming and cause sample degradation. To address these concerns, we report a metabolomics workflow using a mass spectrometry-compatible fabric phase sorptive extraction (FPSE) technique. FPSE employs a matrix coated with sol-gel poly(caprolactone-b-dimethylsiloxane-b-caprolactone) that binds both polar and nonpolar metabolites in whole blood, eliminating serum processing steps. We confirm that the FPSE preparation technique combined with liquid chromatography-mass spectrometry can distinguish radiation exposure markers such as taurine, carnitine, arachidonic acid, α-linolenic acid, and oleic acid found 24 h after 8 Gy irradiation. We also note the effect of different membrane fibers on both metabolite extraction efficiency and the temporal stabilization of metabolites in whole blood at room temperature. These findings suggest that the FPSE approach could work in future technology to triage irradiated individuals accurately, via biomarker screening, by providing a novel method to stabilize biofluids between collection and sample analysis.

Abstract 2932: Withanolide D enhances radiosensitivity of human cancer cells to X-rays radiation

Along with surgery and chemotherapy, radiation therapy (RT) is an important modality in cancer treatment, with about half of cancer patients receiving RT during their treatment. However, there are still a lot of challenges to improve its efficiency by minimizing normal tissue toxicity while maximizing tumor control. In this perspective, radiosensitizers are a promising approach in order to create a better tumor response to ionizing radiation (IR) while allowing for better dose modulation. Withanolides are natural steroidal lactones found in the plant Withania somnifera and already known for their numerous biological effects, in particular an antitumor activity due to induction of ROS production, cell cycle arrest or cytoskeleton destabilization. Hence, we tested in this study our hypothesis that withanolide D (WD), a compound with an important antitumor effect, could also act as a radiosensitizer. Clonogenic assays showed that 1-hour WD pretreatment (0.7µM) before IR decreased surviving fraction of several cancer cell lines. To determine the mechanisms by which WD achieves its radiosensitizing effect, we then assessed whether WD could promote radiation-induced DNA damages and inhibit double-strand breaks (DSBs) repair in SKOV3 cells. Comet and γH2AX/53BP1 foci formation assays confirmed that DSBs are higher from 1 hour up to 24 hours after 2Gy-irradiation in WD-treated cells compared to vehicle-treated cells, suggesting that WD induces the persistence of radiation-induced DNA damages. We then performed immunoblotting to investigate protein expression involved in DNA repair pathways. Interestingly, DNA-PK, ATM and their phosphorylated forms appeared to be inhibited at 24 hours post-irradiation in WD-treated samples. XRCC4 expression is also decreased while RAD51 expression does not change compared to vehicle-treated cells suggesting that only non-homologous end joining pathways is altered by WD. In order to assess the consequence of such inhibition, we then investigated cell death, and especially delayed death, referred to as mitotic catastrophe (MC), which was described as the main form of epithelial cell death induced by IR. MC is induced after IR and but is predominant in WD-treated samples as showed by the few numbers of cells pursing into anaphase. Interestingly, our results showed that cells preferentially undergo necrosis-like death after MC instead of apoptosis. This can be explained by the p53 mutated profile of SKOV3 in addition to the WD-induced ATM inhibition. Together, these data demonstrate that WD is a promising radiosensitizer candidate for RT and additional studies are required to investigate its effect in more relevant clinical models.

Citation Format: Jerome Lacombe, Titouan Cretignier, Laetitia Meli, Jean-Luc Veuthey, Leslie Gunatilaka, Muriel Cuendet, Frederic Zenhausern. Withanolide D enhances radiosensitivity of human cancer cells to X-rays radiation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2932.

Candidate gene biodosimetry markers of exposure to external ionizing radiation in human blood: A systematic review

Purpose

To compile a list of genes that have been reported to be affected by external ionizing radiation (IR) and to assess their performance as candidate biomarkers for individual human radiation dosimetry.

Methods

Eligible studies were identified through extensive searches of the online databases from 1978 to 2017. Original English-language publications of microarray studies assessing radiation-induced changes in gene expression levels in human blood after external IR were included. Genes identified in at least half of the selected studies were retained for bio-statistical analysis in order to evaluate their diagnostic ability.

Results

24 studies met the criteria and were included in this study. Radiation-induced expression of 10,170 unique genes was identified and the 31 genes that have been identified in at least 50% of studies (12/24 studies) were selected for diagnostic power analysis. Twenty-seven genes showed a significant Spearman’s correlation with radiation dose. Individually, TNFSF4, FDXR, MYC, ZMAT3 and GADD45A provided the best discrimination of radiation dose < 2 Gy and dose ≥ 2 Gy according to according to their maximized Youden’s index (0.67, 0.55, 0.55, 0.55 and 0.53 respectively). Moreover, 12 combinations of three genes display an area under the Receiver Operating Curve (ROC) curve (AUC) = 1 reinforcing the concept of biomarker combinations instead of looking for an ideal and unique biomarker.

Conclusion

Gene expression is a promising approach for radiation dosimetry assessment. A list of robust candidate biomarkers has been identified from analysis of the studies published to date, confirming for example the potential of well-known genes such as FDXR and TNFSF4 or highlighting other promising gene such as ZMAT3. However, heterogeneity in protocols and analysis methods will require additional studies to confirm these results.

Analysis of Saliva Gene Expression during Head and Neck Cancer Radiotherapy: A Pilot Study

Saliva, a biological fluid, is a promising candidate for novel approaches to prognosis, clinical diagnosis, monitoring and management of patients with both oral and systemic diseases. However, to date, saliva has not been widely investigated as a biomarker for radiation exposure. Since white blood cells are also present in saliva, it should theoretically be possible to investigate the transcriptional biomarkers of radiation exposure classically studied in whole blood. Therefore, we collected whole blood and saliva samples from eight head and neck cancer patients before the start of radiation treatment, at mid-treatment and after treatment. We then used a panel of five genes: BAX, BBC3, CDKN1A, DDB2 and MDM2, designated for assessing radiation dose in whole blood to evaluate gene expression changes that can occur during radiotherapy. The results revealed that the expression of the five genes did not change in whole blood. However, in saliva, CDKN1A and DDB2 were significantly overexpressed at the end, compared to the start, of radiotherapy, and MDM2 was significantly underexpressed between mid-treatment and at the end of treatment. Interestingly, CDKN1A and DDB2 expressions also showed an increasing monotonic relationship with total radiation dose received during radiotherapy. To our knowledge, these results show for the first time the ability to detect gene expression changes in saliva after head and neck cancer radiotherapy, and pave the way for further promising studies validating saliva as a minimally invasive means of biofluid collection to directly measure radiation dose escalation during treatment.

Controlling self-patterning of acrylate films by photopolymerization

Acrylate formulations can spontaneously generate surface patterns by UV-curing in open-air.

Lamellar mesoscopic organization of supramolecular polymers: a necessary pre-ordering secondary structure

Thy-functionalized PPGs organize in lamellae due to the alignment of amide links in a β-sheet-like secondary structure analogous to proteins.

Emergence of miR-34a in radiation therapy

Expressions of many microRNAs (miRNAs) in response to ionizing radiation (IR) have already been investigated and some of them seem to play an important role in the tumor radioresistance, normal tissue radiotoxicity or as predictive biomarkers to radiation. miR-34a is an emerging miRNA in recent radiobiology studies. Here, we review this miR-34 family member by detailing its different roles in radiation response and we will discuss about the role that it can play in radiation treatment. Thus, we will show that IR regulates miR-34a by increasing its expression. We will also highlight different biological processes involved in cellular response to IR and regulated by miR-34a in order to demonstrate the role it can play in tumor radio-response or normal tissue radiotoxicity as a radiosensitizer or radioprotector. miR-34a is poised to assert itself as an important player in radiobiology and should become more and more important in radiation therapy management.

Using the Cancer Risk Management Model to evaluate the health and economic impacts of cytology compared with human papillomavirus DNA testing for primary cervical cancer screening in Canada

BACKGROUND

In Canada, discussion about changing from cytology to human papillomavirus (hpv) dna testing for primary screening in cervical cancer is ongoing. However, the Canadian Task Force on Preventive Health Care has not yet made a recommendation, concluding that the evidence is insufficient.

METHODS

We used the cervical cancer and hpv transmission models of the Cancer Risk Management Model to study the health and economic outcomes of primary cytology compared with hpv dna testing in 14 screening scenarios with varying screening modalities and intervals. Projected cervical cancer cases, deaths, colposcopies, screens, costs, and incremental cost-effectiveness were evaluated. We performed sensitivity analyses for hpv dna test costs.

RESULTS

Compared with triennial cytology from age 25, 5-yearly hpv dna screening alone from age 30 resulted in equivalent incident cases and deaths, but 55% (82,000) fewer colposcopies and 43% (1,195,000) fewer screens. At hpv dna screening intervals of 3 years, whether alone or in an age-based sequence with cytology, screening costs are greater, but at intervals of more than 5 years, they are lower. Scenarios on the cost-effectiveness frontier were hpv dna testing alone every 10, 7.5, 5, or 3 years, and triennial cytology starting at age 21 or 25 when combined with hpv dna testing every 3 years.

CONCLUSIONS

Changing from cytology to hpv dna testing as the primary screening test for cervical cancer would be an acceptable strategy in Canada with respect to incidence, mortality, screening and diagnostic test volumes.

Concurrent or sequential letrozole with adjuvant breast radiotherapy: final results of the CO-HO-RT phase II randomized trial

BACKGROUND

We present here final clinical results of the COHORT trial and both translational sub-studies aiming at identifying patients at risk of radiation-induced subcutaneous fibrosis (RISF): (i) radiation-induced lymphocyte apoptosis (RILA) and (ii) candidates of certain single-nucleotide polymorphisms (SNPs).

PATIENTS AND METHODS

Post-menopausal patients with stage I-II breast cancer (n = 150) were enrolled and assigned to either concurrent (arm A) or sequential radiotherapy (RT)-letrozole (arm B). Among them, 121 were eligible for RILA and SNP assays. Grade ≥2 RISF were the primary end point. Secondary end points were lung and heart events and carcinologic outcome. RILA was performed to predict differences in RISF between individuals. A genome-wide association study was performed to identify SNPs associated with RILA and RISF. Analyses were done by intention to treat.

RESULTS

After a median follow-up of 74 months, 5 patients developed a grade ≥2 RISF. No significant difference was observed between arms A and B. Neither grade ≥2 lung nor symptomatic cardiac toxicity was observed. Median RILA value of the five patients who had grade ≥2 RISF was significantly lower compared with those who developed grade ≤1 RISF (6.9% versus 13%, P = 0.02). Two SNPs were identified as being significantly associated with RILA: rs1182531 (P = 4.2 × 10(-9)) and rs1182532 (P = 3.6 × 10(-8)); both located within the PHACTR3 gene on chromosome 20q13.33.

CONCLUSIONS

With long-term follow-up, letrozole can safely be delivered concomitantly with adjuvant breast RT. Translational sub-studies showed that high RILA values were correlated with patients who did not develop RISF.

REGISTERED CLINICAL TRIAL

NCT00208273.

Microfluidics as a new tool in radiation biology

Ionizing radiations interact with molecules at the cellular and molecular levels leading to several biochemical modifications that may be responsible for biological effects on tissue or whole organisms. The study of these changes is difficult because of the complexity of the biological response(s) to radiations and the lack of reliable models able to mimic the whole molecular phenomenon and different communications between the various cell networks, from the cell activation to the macroscopic effect at the tissue or organismal level. Microfluidics, the science and technology of systems that can handle small amounts of fluids in confined and controlled environment, has been an emerging field for several years. Some microfluidic devices, even at early stages of development, may already help radiobiological research by proposing new approaches to study cellular, tissue and total-body behavior upon irradiation. These devices may also be used in clinical biodosimetry since microfluidic technology is frequently developed for integrating complex bioassay chemistries into automated user-friendly, reproducible and sensitive analyses. In this review, we discuss the use, numerous advantages, and possible future of microfluidic technology in the field of radiobiology. We will also examine the disadvantages and required improvements for microfluidics to be fully practical in radiation research and to become an enabling tool for radiobiologists and radiation oncologists.

[Intrinsic radiosensitivity: predictive assays that will change daily practice]

The impact of curative radiotherapy depends mainly on the total dose delivered homogenously in the targeted volume. Nevertheless, the dose delivered to the surrounding healthy tissues may reduce the therapeutic ratio of many radiation treatments. In a same population treated in one center with the same technique, it appears that individual radiosensitivity clearly exists, namely in terms of late side effects that are in principle non-reversible. This review details the different radiobiological approaches that have been developed to better understand the mechanisms of radiation-induced late effects. We also present the possibilities of clinical use of predictive assays in the close future.

[Interest of blood markers in predicting radiation-induced toxicity]

The oncologic outcome and the total dose are highly correlated with the treatment by ionizing radiation. The dose increase (total or per fraction) may provoke late-side effects that are potentially irreversible. The radiation-induced CD8 lymphocyte apoptotic value and the molecular modifications within the lymphocyte are capable of predicting the level of risk of developing late-side effects after curative intent radiotherapy. In this review, we present the different blood assays in this setting and discuss the current possibilities of researches, namely those involving the proteomic process.

Comparison of somatostatin receptor expression in human gliomas and medulloblastomas

The expression of the five somatostatin receptor subtypes, sst1-5 was compared on tissue containing glial tumours (glioblastomas or oligodendrogliomas), medulloblastomas, and on normal human cortex. By semiquantitative reverse transcription coupled to polymerase chain reaction, the receptor expression profiles were high in cortex and in tissue containing oligodendrogliomas. It was moderate in medulloblastomas. Tissue containing glioblastomas displayed lower expression of somatostatin receptor subtypes, sst1 and sst3 being mostly expressed. By 125I-Tyr0DTrp8 somatostatin-14 or 125I-Leu8DTrp22 Tyr25 somatostatin-28 autoradiography combined with synaptophysin immunohistochemistry, it was possible to differentiate between isolated tumoral cell component infiltrating the cerebral parenchyma (cortex or white matter) and tumoral tissue (without residual parenchyma) in glioblastomas or oligodendrogliomas. Glial tumoral tissue per se presented few somatostatin receptors. By contrast, medulloblastoma tumoral cells exhibited numerous octreotide sensitive somatostatin receptors. sst2 immunocytochemistry demonstrated immunostaining of neuronal cells and neuropile; sst2 and sst3 immunostaining was identified on glioblastoma proliferating vessels endothelial cells and on medulloblastomas tumoral cells. Faint sst2 immunostaining among glial tumoral cells was due to microglia, while glioma cells did not significantly stain. In summary, medulloblastoma tumoral cells express sst2/sst3 receptors at a high level while glioma cells do not. In gliomas, sst expression is restricted to endothelial cells on proliferating vessels (displaying both sst2 and sst3 receptors), including parenchyma and reactive microglia (only sst2). The differential expression of sst2/sst3 receptors on gliomas and medulloblastomas has implications for the therapy of these tumours.

The Kex2p proregion is essential for the biosynthesis of an active enzyme and requires a C-terminal basic residue for its function

The Saccharomyces cerevisiae prohormone-processing enzyme Kex2p is biosynthesized as an inactive precursor extended by its N-terminal proregion. Here we show that deletion of the proregion renders Kex2p inactive both in vivo and in vitro. Absence of the proregion impaired glycosylation and stability and resulted in the retention of the enzyme in the endoplasmic reticulum. These phenotypes were partially complemented by expression of the proregion in trans. Trans complementation was specific to Kex2p proregion because expression of any of the seven mammalian prohormone convertase propeptides had no effect. These data are consistent with a model whereby Kex2p proregion functions as an intramolecular chaperone and indicate that covalent linkage to the protein is not an absolute requirement for proregion function. Furthermore, extensive mutagenesis revealed that, in addition to their function as proteolytic recognition sites, C-terminal basic residues play an active role in proregion-dependent Kex2p activation.

Retinoic acid modulates RAR alpha and RAR beta receptors in human glioma cell lines

To identify retinoic acid (RA) signalling pathways involved in growth and differentiation in cells of the glial lineage, two human glioma ceh lines were studied. The three RA receptors (RARs) mRNAs were constitutively expressed, and of the three RXRs, RXR beta appeared predominant. Western blotting analysis confirmed the constitutive expression of RAR alpha and RAR beta. Treatment with all-trans-RA induced morphological changes in the two cell lines, which progressed from their normal pattern of randomly oriented spindle-shaped cells to fibroblast-like glial cells. RA up-regulated RAR alpha and RAR beta mRNAs in both cell lines. Interestingly, RA treatment up-regulated RAR beta proteins but not RAR alpha proteins, suggesting post-transcriptional regulations of RAR transcripts in glioma cells.

Opportunities for cooperation in the domain of informatics and telecommunications applied to health

The European Community (EC) plays an important part in the stimulation of coordinated Research and Development activities in Europe. This paper describes features of the EC framework programmes, and gives an overview of the opportunities for the support of activities in Technology Assessment of PACS.

An arterial prosthesis from Argentina: the Barone Microvelour arterial graft

The manufacture of a polyester vascular prosthesis in the southern hemisphere is a new development in the global dissemination of this maturing technology. Hence the recent introduction of the Barone Microvelour arterial graft from Argentina has highlighted the need for a comparative in vitro and in vivo study to compare its structure and performance with that of existing commercial products. Following a series of laboratory tests and implantations as a thoracoabdominal bypass in dogs, the Barone Microvelour has been identified as a strong graft constructed after the style of early weft-knitted designs. It provides an equivalent sequence and rate of healing to that of other polyester knitted grafts.

Night sleep heart rate patterns recorded by cardiopneumography at home in normal and at-risk for SIDS infants

It has been reported that infants at higher than normal epidemiological risk for the sudden infant death syndrome (SIDS) have abnormal cardiac autonomic activity. A prospective work was performed using cardiopneumographic recordings (CPG) in order to evaluate heart rate (HR) and heart rate variability (HRV) patterns in sleeping normal control infants (C) and in infants at-risk for SIDS in their normal environment at home. One hundred appropriate-for-gestational age full-term infants were studied: 28 C, 48 SIDS siblings (SS), and 24 near-miss for SIDS (NM) within the first 2 weeks following the first detected apparent life-threatening event. The three groups of infants were comparable with respect to gestational and conceptional ages, birthweights, sex distribution and socio-economic backgrounds. CPG were done over two successive nights. Records were visually analysed for sleep states (quiet: QS, and combined active + indeterminate sleep: AIS) and wakefulness (W) coding. Periods of W were not analysed. An automatic programme allowed us to study HR minute-by-minute, and to assess whether HR and HRV patterns were specific to a certain part of the night, records were divided into three periods (2200-0040 h, 0041-0320 h, and 0321-0600 h). In C and SS groups, the HR was significantly lower in the 2nd night-period than in the 1st and 3rd periods in both QS and AIS (P less than 0.05). In the NM group this difference was only observed during AIS (P less than 0.05). During the three night-periods the HR was significantly elevated in AIS as compared to QS (at least P less than 0.05) in all infant groups except the NM group during the 2nd night-period. During QS the HR was significantly higher in NM than in C and SS groups (P less than 0.02). During AIS the HR did not differ between infant groups. HRV was significantly lower in the NM group during QS in the three night-periods (P less than 0.05). There was no difference in the HR and HRV patterns between C and SS groups with respect to sleep states and night period. We concluded that following the first detected apparent life-threatening event differences in the HR and HRV patterns can be demonstrated when sleeping NM infants are compared with both C and SS infants especially during QS in different night periods studied by CPG at home.

Cardiovascular changes during the sleep-wake cycle in spontaneous hypertensive rats and their genetically normotensive precursors

Blood pressure and heart rate were recorded in spontaneously hypertensive rats (SH) and in their genetically normotensive precursors (WKY) during the sleep-wake cycle using a computer-assisted method. Similar results were obtained in both strains: (a) No significant difference was observed in blood pressure values between slow-wave-sleep (SWS) and the last 2 min of the preceding wakefulness (W) episode within the complete cycle; blood pressure then increased during PS. (b) Heart rate values during SWS were significantly lower than those computed for W; a further fall of heart rate was observed during paradoxical sleep (PS) only in hypertensive rats. (c) During SWS the blood pressure and heart rate variability was significantly lower than during W and PS. In addition, blood pressure variability values during the three sleep-wake states were lower in hypertensive than in normotensive rats. These data suggest that there are no qualitative differences in the mechanisms that control circulation during sleep in normotensive and spontaneous hypertensive rats.

Computer analysis of cardiovascular changes during sleep-wake cycle in Sprague-Dawley rats

Blood pressure (BP) and heart rate (HR) were recorded in seven Sprague-Dawley rats during a total of 491 normal sleep-wake cycles with the use of a computer-assisted method developed for this study. Significant changes of BP, HR, and BP variability (BPV) were found between the three states within the cycle, i.e., wakefulness (W), slow-wave sleep (SWS), and paradoxical sleep (PS). The highest BP, BPV, and HR values were found during W. Then all cardiovascular (CV) variables fell during SWS, whereas BP and BPV rose again during PS. The fall of BPV observed during SWS was the most important CV change observed within the cycle. These state-dependent CV changes suggest that, in the rat, circulation during the sleep-wake cycle is controlled by the same central factors that operate in cats. In addition, significant BP and HR modifications between different cycles have been found. On the other hand, BP and HR differences between animals were also observed. The latter differences were found to be stable across the states, but no significant relation was found between BP and HR within any state. Thus the present data also suggest that BP and HR measurements are influenced not only by state-dependent factors but also by at least three different factors that are each independent of the state: one leads to BP and HR values that are influenced by the cycle the animal is in and the other two influence, respectively, the ranking of the individual's BP and HR levels within the population.

[Transcutaneous oxygen tension and apnea during sleep stages in normal infants and infants at risk for sudden infant death syndrome]

The relationship between chronic hypoxemia and sudden infant death syndrome (SIDS) has been reported by several authors. In order to study the influence of the apnea-time during a sleep state on transcutaneous oxygen tension (tcPO2), we have studied polygraphically 30 full-term infants (10 controls, 10 SIDS siblings and 10 near-miss for SIDS), aged from 5 to 13 weeks. No significant difference was observed either for apnea-time or tcPO2 between infant-groups studied in different sleep states. We could not find any correlation between apnea-time and tcPO2 in all groups of infants studied during different states of sleep. It is therefore concluded that in normal and at risk for SIDS infants, tcPO2 levels during sleep states cannot be explained only by the apnea-time.

Intraspinal lipomas with spina bifida. Prognosis and treatment in 73 cases

The authors present a series of 73 cases of intraspinal lipomas in the lumbosacral region. Sixty-four patients were operated on, 43 of these under intraoperative monitoring of neural function. The results of this series and of major series published in the past 10 years demonstrate both the potential severity of these lesions (which are responsible for progressive neurological deficits in 56% of affected cases) and the benignity of their surgical treatment. The authors emphasize the usefulness of systematic early surgical treatment of these lesions.

Polysomnograms and cardiopneumograms in SIDS research

Polysomnographic (PSG) and cardiopneumographic (CPG) recordings are commonly used in research on sudden infant death syndrome (SIDS). PSG and simultaneous CPG recordings were compared in order to clarify two practical problems: reliability of sleep state evaluation with CPG and comparability of the number of respiratory pauses evaluated by these two recording techniques. This comparison shows that: (1) evaluation of sleep states by CPG technique is only reliable for quiet sleep and (2) there was a significant difference in the number of pauses, the evaluation with PSG being systematically higher than with CPG. The abnormalities found or suspected in CPG home recordings must be confirmed by PSG in the laboratory.