Dynamic Biological Responses Research Articles

Enhancing outcome prediction of concurrent chemoradiation treatment in patients with locally advanced cervical cancer through plasma extracellular vesicle proteomics

Most patients with locally advanced cervical cancer (LACC) are primarily treated using concurrent chemoradiation (CCRT); however, LACC lacks reliable predictive biomarkers. Extracellular vesicles (EVs) could define the dynamic biological response to CCRT. However, the relationship between EVs and the therapeutic response to LACC is unestablished. Thus, we aimed to determine the relationship of plasma EVs pre- and post-CCRT in 62 patients with LACC. For proteomic analyses, EVs were isolated using ultracentrifugation (UC) with size exclusion chromatography or UC alone. We found that plasma particle concentration was significantly increased post-treatment in non-responders. After CCRT, there was a decrease in proteins related to serine protease and fibrinogen, which contribute to tumor microenvironment alteration. This reduction also extended to proteins involved in innate immune and viral immune responses, correlating with reduced tumor burden. Sparse partial least squares discriminant analysis revealed 8, 13, and 19 proteins at diagnosis, one month, and three months, respectively, influencing the CCRT response. Among these, FIBG, TFR1, HBA, and FINC are prognostic markers according to The Cancer Genome Atlas tissue gene expression database. Our discriminant model demonstrated excellent specificity and negative predictive value, underscoring the model's reliability in determining responsiveness to CCRT and highlighting the potential clinical applicability of EVs in improving outcomes in LACC.

Dynamic molecular signatures of acute myocardial infarction based on transcriptomics and metabolomics

Acute myocardial infarction (AMI) commonly precedes ventricular remodeling, heart failure. Few dynamic molecular signatures have gained widespread acceptance in mainstream clinical testing despite the discovery of many potential candidates. These unmet needs with respect to biomarker and drug discovery of AMI necessitate a prioritization. We enrolled patients with AMI aged between 30 and 70. RNA-seq analysis was performed on the peripheral blood mononuclear cells collected from the patients at three time points: 1 day, 7 days, and 3 months after AMI. PLC/LC–MS analysis was conducted on the peripheral blood plasma collected from these patients at the same three time points. Differential genes and metabolites between groups were screened by bio-informatics methods to understand the dynamic changes of AMI in different periods. We obtained 15 transcriptional and 95 metabolite expression profiles at three time points after AMI through high-throughput sequencing. AMI-1d: enrichment analysis revealed the biological features of 1 day after AMI primarily included acute inflammatory response, elevated glycerophospholipid metabolism, and decreased protein synthesis capacity. Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) might stand promising biomarkers to differentiate post-AMI stage. Anti-inflammatory therapy during the acute phase is an important direction for preventing related pathology. AMI-7d: the biological features of this stage primarily involved the initiation of cardiac fibrosis response and activation of platelet adhesion pathways. Accompanied by upregulated TGF-beta signaling pathway and ECM receptor interaction, GP5 help assess platelet activation, a potential therapeutic target to improve haemostasis. AMI-3m: the biological features of 3 months after AMI primarily showed a vascular regeneration response with VEGF signaling pathway, NOS3 and SHC2 widely activated, which holds promise for providing new therapeutic approaches for AMI. Our analysis highlights transcriptional and metabolomics signatures at different time points after MI, which deepens our understanding of the dynamic biological responses and associated molecular mechanisms that occur during cardiac repair.

In vivo imaging of the neuronal response to spinal cord injury: a narrative review.

Deciphering the neuronal response to injury in the spinal cord is essential for exploring treatment strategies for spinal cord injury (SCI). However, this subject has been neglected in part because appropriate tools are lacking. Emerging in vivo imaging and labeling methods offer great potential for observing dynamic neural processes in the central nervous system in conditions of health and disease. This review first discusses in vivo imaging of the mouse spinal cord with a focus on the latest imaging techniques, and then analyzes the dynamic biological response of spinal cord sensory and motor neurons to SCI. We then summarize and compare the techniques behind these studies and clarify the advantages of in vivo imaging compared with traditional neuroscience examinations. Finally, we identify the challenges and possible solutions for spinal cord neuron imaging.

Switching of Photocatalytic Tyrosine/Histidine Labeling and Application to Photocatalytic Proximity Labeling.

Weak and transient protein interactions are involved in dynamic biological responses and are an important research subject; however, methods to elucidate such interactions are lacking. Proximity labeling is a promising technique for labeling transient ligand–binding proteins and protein–protein interaction partners of analytes via an irreversible covalent bond. Expanding chemical tools for proximity labeling is required to analyze the interactome. We developed several photocatalytic proximity-labeling reactions mediated by two different mechanisms. We found that numerous dye molecules can function as catalysts for protein labeling. We also identified catalysts that selectively modify tyrosine and histidine residues and evaluated their mechanisms. Model experiments using HaloTag were performed to demonstrate photocatalytic proximity labeling. We found that both ATTO465, which catalyzes labeling by a single electron transfer, and BODIPY, which catalyzes labeling by singlet oxygen, catalyze proximity labeling in cells.

Comparison of cytotoxicity evaluation of chlorogenic acid extract between Real-time cell analysis and CCK-8 method

Critical cytotoxicity evaluation of pharmaceuticals is necessary for the clinical practice of chemotherapy. To quantitatively evaluate cell viability, currently there are two main types of sensitive methods including real-time cell analysis (RTCA) and CCK-8 assay, in which RTCA records electrochemical signal changes around an incubated cell, whereas CCK-8 is based on the colorimetric method. Despite the different detection principles adopted for the cytotoxicity assessment, the comparison of the two methods in terms of the application scope is lacking. In order to compare and determine the best experimental method for the study of the toxicity of chlorogenic acid extract from taraxacum officinale on dairy cow mammary epithelial cells. The real time cell analysis (RTCA) and CCK-8 method were used to analyze the cytotoxicity of chlorogenic acid extract to BMEC and calculate its IC50. The results of the real time cell analysis method and the CCK-8 method showed that different concentrations of chlorogenic acid extract reduced the viability of dairy cow mammary epithelial cells, and the decrease was most obvious at 400 ug/mL. The IC50 of the two analysis methods were 326.8 and 320.4 ug/mL, respectively. In contrast, the CCK-8 method had limitations in fixed-point determination. However, the real time cell analysis method can monitor the dynamic biological response process of cell growth and proliferation in real time. Therefore, the real time cell analysis method can observe cell growth more intuitively and accurately, compensate for the shortcomings of the CCK-8 method, and it is a new experimental method for studying cytotoxicity.

Immune Reprogramming in Human Subjects after Extracorporeal Mesenchymal Stromal Cell Therapy

Background & Aim Mesenchymal stromal cells (MSCs) are a unique source of secreted factors that modulate an inflammatory response and enhance the repair of injured tissue. Sentien has created a novel delivery approach to enable sustained exposure to MSCs and their secreted factors, overcoming limits of cell transplantation/infusion while preserving the broad acting and dynamically responsive properties. Our lead product, SBI-101, contains allogeneic human MSCs inoculated into a hollow-fiber hemofilter, which promotes contact with patient blood via the semi-permeable membrane, while promoting MSC viability. SBI-101 is designed to restore balance to the immune system by reprograming the molecular and cellular components of blood in patients with severe organ injury. We are conducting a Phase I/II clinical study of SBI-101 in critically ill patients with Dialysis-Requiring Acute Kidney Injury (AKI-D). Methods, Results & Conclusion In the initial cohort analyzed, patients were randomized to receive SBI-101 (250 × 106 cells) or sham control up to 24 hours of treatment (n=4 per group). Over 200 exploratory biomarkers were measured to characterize the MSC response as well as the pharmacodynamic (PD) effects of SBI-101. Samples were collected for the measurement of immune cell populations, kidney injury biomarkers, and biomarkers of inflammation at pre dose, conclusion of treatment, days 1, 3, 7, 14, 21, and 28 post-treatment with SBI-101 or sham control. Data showed an MSC response that seems to be dynamic and specific to each patient. Trends in PD response were also observed. Inflammatory (anti- and pro-) markers, such as IL-10 and TNFa, consistent with MSC biology were shown to be modulated, suggestive of a shift from a pro- to anti- inflammatory state. In addition, innate and adaptive cellular immune changes were also observed, such as reduction in total monocytes. Finally, early markers of kidney injury (eg, KIM-1) were also seen to have effect sizes greater than one. Despite therapy being administered for a maximum of 24 hours, a durable effect was observed out to a week in some cases. While the study was not powered for significance, the results demonstrate a dynamic biological response from the MSCs with potentially beneficial effects in the immune system as well as in the kidney of these critically ill patients. Moreover, it supports the therapeutic hypothesis of SBI-101 as a potent immunotherapy.

Abstract 3738: A STING independent type-1 interferon response induced by fractionated radiotherapy coincides with altered tumor growth and clonogenicity

Abstract Introduction To improve radiotherapy efficacy, insight in the dynamic biological responses that occur during clinical radiation schedules is vital. In the current study we explored gene expression changes during the course of fractionated radiotherapy (FrRT) that might be targeted with combination treatment strategies. Methods Human cell lines HT29, SW480, HCT116, COLO320, RKO (colorectal carcinoma), D384 (glioblastoma) and OE19 (esophageal adenocarcinoma) as well as HT29 xenograft tumors in nude mice were irradiated up to 3 to 5 weeks with daily fractions of 2 Gy for 5 days per week. In vivo tumor growth was monitored daily and in vitro clonogenic survival was determined every other day. At the end of each treatment week tumors and cells were harvested for RNA isolation. Subsequently, gene expression analysis was performed by RNA sequencing and micro-array analysis. Altered gene expression levels were validated by qPCR. Protein expression was determined by ELISA and Western blot. Results Tumor growth of the HT29 xenografts declined after 2 weeks of FrRT compared to non-irradiated tumors. In irradiated cell lines, clonogenic survival analyses revealed a log-linear decline in survival in the first 2 weeks, after which a steady-state-like phase was reached up to 5 treatment weeks. Gene expression analysis of both xenograft tumors as well as irradiated cell lines at this 2 week time point identified a type-1 interferon (IFN) mediated signaling pathway as the most significantly enriched biological process. The induction of a selection of IFN-stimulated genes (ISGs) was confirmed by qPCR. Comparable responses were observed in both STING positive (HT29, SW480, HCT116, D384) and negative (COLO320, RKO, OE19) cell lines. To get more insight in the dynamics of the IFN response we analyzed ISGs expression at the end of each treatment week. This revealed a peak in ISGs expression after 10 to 15 fractions, both in vivo and in vitro. The ISGs expression levels decreased with continuation of treatment but always remained above the basal level of non-irradiated cells. Single dose irradiation up to 10 Gy also induced dose-dependent ISGs expression, albeit typically 5 to 10 fold lower as compared to FrRT. Subsequent protein and mRNA expression analyses consistently revealed induction of IFN beta expression, with peak levels measured after 10 to 15 fractions. In addition, occasional induction of IFN lambda 2/3 protein and mRNA expression was observed. Conclusion FrRT induces an intrinsic type-1 IFN response which occurs independent of STING. This response is associated with induction of IFN beta expression, which peaks after 2 to 3 weeks of treatment and coincides with a shift in in vivo tumor growth and in vitro clonogenic survival. Targeting this response during FrRT might be exploited as a novel combination treatment. Citation Format: Ruben S. Goedegebuure, Esther A. Kleibeuker, Kitty C. Castricum, Jaap van den Berg, Sarah Derks, Henk M. Verheul, Ben J. Slotman, Adrian Harris, Victor L. Thijssen. A STING independent type-1 interferon response induced by fractionated radiotherapy coincides with altered tumor growth and clonogenicity [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 3738.

Massively Parallel Single Nucleus Transcriptional Profiling Defines Spinal Cord Neurons and Their Activity during Behavior

SUMMARYTo understand the cellular basis of behavior, it is necessary to know the cell types that exist in the nervous system and their contributions to function. Spinal networks are essential for sensory processing and motor behavior and provide a powerful system for identifying the cellular correlates of behavior. Here, we used massively parallel single nucleus RNA sequencing (snRNA-seq) to create an atlas of the adult mouse lumbar spinal cord. We identified and molecularly characterized 43 neuronal populations. Next, we leveraged the snRNA-seq approach to provide unbiased identification of neuronal populations that were active following a sensory and a motor behavior, using a transcriptional signature of neuronal activity. This approach can be used in the future to link single nucleus gene expression data with dynamic biological responses to behavior, injury, and disease.

Molecular Imaging of Neuroinflammation in Neurodegenerative Dementias: The Role of In Vivo PET Imaging.

Neurodegeneration elicits neuroinflammatory responses to kill pathogens, clear debris and support tissue repair. Neuroinflammation is a dynamic biological response characterized by the recruitment of innate and adaptive immune system cells in the site of tissue damage. Resident microglia and infiltrating immune cells partake in the restoration of central nervous system homeostasis. Nevertheless, their activation may shift to chronic and aggressive responses, which jeopardize neuron survival and may contribute to the disease process itself. Positron Emission Tomography (PET) molecular imaging represents a unique tool contributing to in vivo investigating of neuroinflammatory processes in patients. In the present review, we first provide an overview on the molecular basis of neuroinflammation in neurodegenerative diseases with emphasis on microglia activation, astrocytosis and the molecular targets for PET imaging. Then, we review the state-of-the-art of in vivo PET imaging for neuroinflammation in dementia conditions associated with different proteinopathies, such as Alzheimer’s disease, frontotemporal lobar degeneration and Parkinsonian spectrum.

Chemical approaches to discovery and study of sources and targets of hydrogen peroxide redox signaling through NADPH oxidase proteins.

Hydrogen peroxide (H2O2) is a prime member of the reactive oxygen species (ROS) family of molecules produced during normal cell function and in response to various stimuli, but if left unchecked, it can inflict oxidative damage on all types of biological macromolecules and lead to cell death. In this context, a major source of H2O2 for redox signaling purposes is the NADPH oxidase (Nox) family of enzymes, which were classically studied for their roles in phagocytic immune response but have now been found to exist in virtually all mammalian cell types in various isoforms with distinct tissue and subcellular localizations. Downstream of this tightly regulated ROS generation, site-specific, reversible covalent modification of proteins, particularly oxidation of cysteine thiols to sulfenic acids, represents a prominent posttranslational modification akin to phosphorylation as an emerging molecular mechanism for transforming an oxidant signal into a dynamic biological response. We review two complementary types of chemical tools that enable (a) specific detection of H2O2 generated at its sources and (b) mapping of sulfenic acid posttranslational modification targets that mediate its signaling functions, which can be used to study this important chemical signal in biological systems.

Real-Time Analysis of Cellular Response to Small-Molecule Drugs within a Microfluidic Dielectrophoresis Device.

Quantitative detection of the biological properties of living cells is essential for a wide range of purposes, from the understanding of cellular characteristics to the development of novel drugs in nanomedicine. Here, we demonstrate that analysis of cell biological properties within a microfluidic dielectrophoresis device enables quantitative detection of cellular biological properties and simultaneously allows large-scale measurement in a noise-robust and probeless manner. Applying this technique, the static and dynamic biological responses of live B16F10 melanoma cells to the small-molecule drugs such as N-ethylmaleimide (NEM) and [(dihydronindenyl)oxy]alkanoic acid (DIOA) were quantitatively and statistically examined by investigating changes in movement of the cells. Measurement was achieved using subtle variations in dielectrophoresis (DEP) properties of the cells, which were attributed to activation or deactivation of K(+)/Cl(-) cotransporter channels on the cell membrane by the small-molecule drugs, in a microfluidic device. On the basis of quantitative analysis data, we also provide the first report of the shift of the complex permittivity of a cell induced by the small-molecule drugs. In addition, we demonstrate interesting quantifiable parameters including the drug effectiveness coefficient, antagonistic interaction coefficient, kinetic rate, and full width at half-maximum, which corresponded to changes in biological properties of B16F10 cells over time when NEM and DIOA were introduced alone or in combination. Those demonstrated parameters represent very useful tools for evaluating the effect of small-molecule drugs on the biological properties of cells.

Hepatocyte growth factor and Met in drug discovery.

Activation of the hepatocyte growth factor (HGF)-Met pathway evokes dynamic biological responses that support the morphogenesis, regeneration and survival of cells and tissues. A characterization of conditional Met knockout mice indicates that the HGF-Met pathway plays important roles in the regeneration, protection and homeostasis of cells such as hepatocytes, renal tubular cells and neurons. Preclinical studies in disease models have indicated that recombinant HGF protein and expression plasmid for HGF are biological drug candidates for the treatment of patients with diseases or injuries that involve impaired tissue function. The phase-I and phase-I/II clinical trials of the intrathecal administration of HGF protein for the treatment of patients with amyotrophic lateral sclerosis and spinal cord injury, respectively, are ongoing. Biological actions of HGF that promote the dynamic movement, morphogenesis and survival of cells also closely participate in invasion-metastasis and resistance to the molecular-targeted drugs in tumour cells. Different types of HGF-Met pathway inhibitors are now in clinical trials for treatment of malignant tumours. Basic research on HGF and Met has lead to drug discoveries in regenerative medicine and tumour biology.

HGF-Met Pathway in Regeneration and Drug Discovery.

Hepatocyte growth factor (HGF) is composed of an α-chain and a β-chain, and these chains contain four kringle domains and a serine protease-like structure, respectively. Activation of the HGF–Met pathway evokes dynamic biological responses that support morphogenesis (e.g., epithelial tubulogenesis), regeneration, and the survival of cells and tissues. Characterizations of conditional Met knockout mice have indicated that the HGF–Met pathway plays important roles in regeneration, protection, and homeostasis in various cells and tissues, which includes hepatocytes, renal tubular cells, and neurons. Preclinical studies designed to address the therapeutic significance of HGF have been performed on injury/disease models, including acute tissue injury, chronic fibrosis, and cardiovascular and neurodegenerative diseases. The promotion of cell growth, survival, migration, and morphogenesis that is associated with extracellular matrix proteolysis are the biological activities that underlie the therapeutic actions of HGF. Recombinant HGF protein and the expression vectors for HGF are biological drug candidates for the treatment of patients with diseases and injuries that are associated with impaired tissue function. The intravenous/systemic administration of recombinant HGF protein has been well tolerated in phase I/II clinical trials. The phase-I and phase-I/II clinical trials of the intrathecal administration of HGF protein for the treatment of patients with amyotrophic lateral sclerosis and spinal cord injury, respectively, are ongoing.

Extinction and recolonization of coastal megafauna following human arrival in New Zealand.

Extinctions can dramatically reshape biological communities. As a case in point, ancient mass extinction events apparently facilitated dramatic new evolutionary radiations of surviving lineages. However, scientists have yet to fully understand the consequences of more recent biological upheaval, such as the megafaunal extinctions that occurred globally over the past 50 kyr. New Zealand was the world's last large landmass to be colonized by humans, and its exceptional archaeological record documents a vast number of vertebrate extinctions in the immediate aftermath of Polynesian arrival approximately AD 1280. This recently colonized archipelago thus presents an outstanding opportunity to test for rapid biological responses to extinction. Here, we use ancient DNA (aDNA) analysis to show that extinction of an endemic sea lion lineage (Phocarctos spp.) apparently facilitated a subsequent northward range expansion of a previously subantarctic-limited lineage. This finding parallels a similar extinction-replacement event in penguins (Megadyptes spp.). In both cases, an endemic mainland clade was completely eliminated soon after human arrival, and then replaced by a genetically divergent clade from the remote subantarctic region, all within the space of a few centuries. These data suggest that ecological and demographic processes can play a role in constraining lineage distributions, even for highly dispersive species, and highlight the potential for dynamic biological responses to extinction.

Dynamic sulfur and carbon cycling through the end-Ordovician extinction revealed by paired sulfate–pyrite δ34S

Geochemical records of the end-Ordovician Hirnantian Stage show parallel positive excursions in the stable isotope compositions of sedimentary pyrite sulfur (δ34Spyr), organic carbon (δ13Corg), and carbonate carbon (δ13Ccarb); these isotope excursions coincide with the end Ordovician glaciation and mass extinction. A relative increase in pyrite burial (fpyr) attributed to marine anoxia has been invoked to explain the sulfur isotope excursion and link oceanic redox conditions to the extinction of marine fauna. An increase in fpyr would necessarily generate a parallel excursion of equal magnitude in the isotopic composition of coeval marine sulfate (δ34SSO4). Here we present new high-resolution paired sulfur isotope data from carbonate-associated sulfate (δ34SCAS) and pyrite from the Hirnantian Stage of western Anticosti Island (Québec, Canada). These data document a positive 20‰ enrichment in δ34Spyr (comparable in magnitude to previous reports), but no parallel excursion in δ34SCAS. This pattern provides new constraints on the origin of the δ34Spyr excursion and the nature of carbon–sulfur coupling through Hirnantian time. Specifically, these observations preclude enhanced pyrite burial as the cause of the Hirnantian δ34Spyr excursion and suggest the possible role of anoxia in the mass extinction may need to be reevaluated. Rather, the global δ34Spyr excursion is best explained by a transient reduction in the isotopic fractionations expressed during microbial sulfur cycling (εpyr). The εpyr record shows a strong inverse correlation with δ13C, suggesting a mechanistic link between carbon cycling and processes controlling εpyr during the Hirnantian. Changes in sea level or marine redox state associated with glaciation could further impact the expression of the biological fractionation (e.g., through syndepositional sediment reworking and/or chemocline migration and resultant restricted exchange of porewater sulfate). The magnitude of isotopic fractionation during microbial sulfate reduction is partially controlled by metabolic rates, which are sensitive to the abundance, type, and lability of metabolically relevant substrates. Environmental change associated with the end Ordovician glaciation may have elevated the flux of organic material to marine sediments or caused an increase in physical reworking of sediments, leading to increased microbial sulfate reduction rates and reduced εpyr. As such, the Hirnantian δ34Spyr excursion may be viewed as a dynamic biological response to global climate change, highlighting the connections between the carbon and sulfur biogeochemical cycles.

Abstract B07: Nasal epithelial gene expression profiles reflect dynamic biological response to smoking cessation

Abstract Rationale: There are few indicators of which cigarette smokers are at highest risk for developing lung cancer and COPD, and it is unclear why individuals remain at risk for decades after smoking-cessation. The kinetics of gene-expression alterations upon smoking-cessation might delineate distinct biological processes that are activated in response to and during recovery from tobacco smoke exposure. Furthermore, differences in this response or recovery might be associated with disease risk. We therefore sought to determine whether the kinetics of gene-expression alterations upon smoking-cessation could be detected in readily collected nasal epithelium. Methods: Nasal epithelial brushings were obtained from 8 active smokers enrolled in smoking-cessation programs. Brushings were obtained at baseline and at 4, 8, 16, and 24-weeks after smoking-cessation. Urine cotinine or exhaled carbon monoxide was used to assess tobacco abstinence. RNA extracted from the nasal brushings was processed and hybridized to Gene 1.0 ST Arrays. Gene expression changes associated with smoking-cessation were identified with a linear mixed effects model. Functional enrichment was determined using DAVID. Gene Set Enrichment Analysis (GSEA) was used to determine the relationship of nasal epithelial gene-expression changes associated with smoking-cessation to previous cross-sectional bronchial and nasal airway gene expression datasets of current, longer-term former and never smokers and to a previous published dataset of in-vitro exposure of cultured bronchial epithelial cells (NHBE) to cigarette smoke (CS). Results: The expression levels of 78 genes were associated with short-term smoking-cessation (FDR q<0.05, FC ≥ 1.75), with 6 genes up-regulated and 72 genes down-regulated with tobacco abstinence. A majority of the changes occur within 1-2 months of quitting. These genes were enriched in functional categories including oxidoreductase activity and metabolism of xenobiotic (p<0.05). Genes that decreased with smoking-cessation were enriched for genes whose expression levels in the airway datasets were higher in current smokers relative to never smokers or longer-term former smokers (FDR <10−3). Genes increased in active smokers that reversed with smoking-cessation were enriched among genes that are induced followed 15 minutes in-vitro exposure of NHBE to CS (FDR <5*10−3). Conclusion: Nasal epithelial gene expression profiles reflect the host response to smoking-cessation and are concordant with reversible changes identified in an independent bronchial airway dataset. Genes that reverse rapidly after smoking-cessation are inversely related to gene expression differences induced by acute cigarette smoke exposure in-vitro; suggesting that aspects of the gene-expression response to tobacco smoke both occur and reverse with rapid kinetics upon smoking. We have further found that genes with different biological functions revert to baseline with different dynamics following smoking-cessation. These data suggest that the smoking-induced field of injury can be measured non-invasively in nasal epithelium and leveraged to understand the kinetics of the reversible impact of smoking. These minimally invasive tools can be applied in population studies to assess the physiological impact of alternate tobacco products and other inhaled environmental exposures. Citation Format: Kahkeshan Hijazi, Bozena Malyszko, Xiaohui Zhang, Gang Liu, Yuriy Alekseyev, Yves-Martine Dumas, Louise Hertsgaard, Joni Jenson, Cindy Rohde, Dorothy K Hatsukami, Stephen S. Hecht, Daniel R Brooks, George O’Connor, Marc Lenburg, Katrina Steiling, Avrum Spira. Nasal epithelial gene expression profiles reflect dynamic biological response to smoking cessation. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr B07.

Relict or colonizer? Extinction and range expansion of penguins in southern New Zealand

Recent human expansion into the Pacific initiated a dramatic avian extinction crisis, and surviving taxa are typically interpreted as declining remnants of previously abundant populations. As a case in point, New Zealand's endangered yellow-eyed penguin (Megadyptes antipodes) is widely considered to have been more abundant and widespread in the past. By contrast, our genetic and morphological analyses of prehistoric, historic and modern penguin samples reveal that this species expanded its range to the New Zealand mainland only in the last few hundred years. This range expansion was apparently facilitated by the extinction of M. antipodes' previously unrecognized sister species following Polynesian settlement in New Zealand. Based on combined genetic and morphological data, we describe this new penguin species, the first known to have suffered human-mediated extinction. The range expansion of M. antipodes so soon after the extinction of its sister species supports a historic paradigmatic shift in New Zealand Polynesian culture. Additionally, such a dynamic biological response to human predation reveals a surprising and less recognized potential for species to have benefited from the extinction of their ecologically similar sister taxa and highlights the complexity of large-scale extinction events.

Fluorescence microscopy imaging of electroperturbation in mammalian cells

We report the design, integration, and validation of a fluorescence microscopy system for imaging of electroperturbation--the effects of nanosecond, megavolt-per-meter pulsed electric fields on biological cells and tissues. Such effects have potential applications in cancer therapy, gene regulation, and biophysical research by noninvasively disrupting intracellular compartments and inducing apoptosis in malignant cells. As the primary observing platform, an epifluorescence microscope integrating a nanosecond high-voltage pulser and a micrometer electrode chamber enable in situ imaging of the intracellular processes triggered by high electric fields. Using specific fluorescence molecular probes, the dynamic biological responses of Jurkat T lymphocytes to nanosecond electric pulses (nanoelectropulses) are studied with this system, including calcium bursts, the polarized translocation of phosphatidylserine (PS), and nuclear enlargement and chromatin/DNA structural changes.

Qualitative holographic study of hemi-pelvic deformation caused by loading different hip prostheses

The dynamic biological response of bone can materially influence the longevity of artificial implants. This paper presents a series of in vitro experiments conducted on epoxy resin models of human hemi-pelves. Different commercially available acetabular components were implanted and used for the construction of simplified three-dimensional models of the artificial hip joint. Boundary conditions included simulation of muscle groups and femoral loading. Real-time holographic interferometry, a stress analysis technique permitting whole-field simultaneous inspection of deformation patterns, was used as the experimental method. The holographic interferograms were interpreted qualitatively rather than quantitatively. High stresses were identified in the hemi-pelvis and it is postulated that these stresses may be implicated in the mechanical pathogenesis of loosening. The obser ed changes in the detected stress levels could influence both future design of acetabular prostheses and surgical techniques.