30 results on '"Jacky Chow"'
Search Results
2. Tumor and immune remodeling following radiotherapy in human renal cell carcinoma
- Author
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Paul K Wallace, Thomas Schwaab, Scott I Abrams, Elizabeth A Repasky, Alexis Conway, Jason B Muhitch, Jacky Chow, Adil Khan, Madeline Gaudieri, Brianna J Wasik, Kah Teong Soh, and Anurag K Singh
- Subjects
Neoplasms. Tumors. Oncology. Including cancer and carcinogens ,RC254-282 - Abstract
Background Studies evaluating peripheral patient samples show radiation can modulate immune responses, yet the biological changes in human tumors particularly at the cellular level remain largely unknown. Here, we address how radiation treatment shapes the immune compartment and interactions with cancer cells within renal cell carcinoma (RCC) patient tumors.Methods To identify how radiation shaped the immune compartment and potential immune interactions with tumor cells we evaluated RCC tumors from patients treated only with nephrectomy or with radiation followed by nephrectomy. Spectral flow cytometry using a 35-marker panel was performed on cell suspensions to evaluate protein expression within immune subsets. To reveal how radiation alters programming of immune populations and interactions with tumor cells, we examined transcriptional changes by single-cell RNA sequencing (scRNAseq).Results Spectral flow cytometry analysis revealed increased levels of early-activated as well as effector programmed cell death protein-1 (PD-1)+ CD8 T-cell subsets within irradiated tumors. Following quality control, scRNAseq of tumor samples from nephrectomy-only or radiation followed by nephrectomy-treated patients generated an atlas containing 34,626 total cells. Transcriptional analysis revealed increased transition from stem-like T-cell populations to effector T cells in irradiated tumors. Interferon (IFN) pathways, that are central to radiation-induced immunogenicity, were enriched in irradiated lymphoid, myeloid, and cancer cell populations. Focused cancer cell analysis showed enhanced antigen presentation and increased predicted TRAIL-mediated and IFN-mediated interactions between tumor cells and the same effector T-cell subsets increased by radiation. TRAIL and IFN pathways enriched in irradiated tumors were associated with survival in patients treated with immunotherapy.Conclusions These findings identify the source of IFN enrichment within irradiated RCC and reveal heightened levels of PD-1+ CD8+ T-cell subsets and increased probability of interactions with tumor cells following standalone radiation treatment. This study provides a window into the irradiated tumor-immune microenvironment of patients and rationale for treatment combinations.
- Published
- 2023
- Full Text
- View/download PDF
3. Quantitative analysis of diaphragm motion during fluoroscopic sniff test to assist in diagnosis of hemidiaphragm paralysis
- Author
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Jacky Chow, MD, MBA, PhD and Muhammed Hatem, MD
- Subjects
Hemidiaphragm elevation ,Diaphragm paralysis ,Fluoroscopic sniff test ,Diaphragm fluoroscopy ,Machine learning ,Gaussian process ,Medical physics. Medical radiology. Nuclear medicine ,R895-920 - Abstract
The current imaging gold standard for detecting paradoxical diaphragm motion and diagnosing hemidiaphragm paralysis is to perform the fluoroscopic sniff test. The images are visually examined by an experienced radiologist, and if one hemidiaphragm ascends while the other descends, then it is described as paradoxical motion, which is highly suggestive of hemidiaphragm paralysis. However, diagnosis can be challenging because diaphragm motion during sniffing is fast, paradoxical motion can be subtle, and the analysis is based on a 2-dimensional projection of a 3-dimensional surface. This paper presents a case of chronic left hemidiaphragm elevation that was initially reported as mild paradoxical motion on fluoroscopy. After measuring the elevations of the diaphragms and modeling their temporal correlation using Gaussian process regression, the systematic trend of the hemidiaphragmatic motion along with its stochastic properties was determined. When analyzing the trajectories of the hemidiaphragms, no statistically significant paradoxical motion was detected. This could potentially change the prognosis if the patient was to consider diaphragm plication as treatment. The presented method provides a more objective analysis of hemidiaphragm motions and can potentially improve diagnostic accuracy.
- Published
- 2022
- Full Text
- View/download PDF
4. Aggregate Filamentous Growth Responses in Yeast
- Author
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Jacky Chow, Heather M. Dionne, Aditi Prabhakar, Amit Mehrotra, Jenn Somboonthum, Beatriz Gonzalez, Mira Edgerton, and Paul J. Cullen
- Subjects
MAP kinase ,Rho GTPase ,cell differentiation ,cell polarity ,cell shape ,collective cellular responses ,Microbiology ,QR1-502 - Abstract
ABSTRACT Many fungal species, including pathogens, undergo a morphogenetic response called filamentous growth, where cells differentiate into a specialized cell type to promote nutrient foraging and surface colonization. Despite the fact that filamentous growth is required for virulence in some plant and animal pathogens, certain aspects of this behavior remain poorly understood. By examining filamentous growth in the budding yeast Saccharomyces cerevisiae and the opportunistic pathogen Candida albicans, we identify responses where cells undergo filamentous growth in groups of cells or aggregates. In S. cerevisiae, aggregate invasive growth was regulated by signaling pathways that control normal filamentous growth. These pathways promoted aggregation in part by fostering aspects of microbial cooperation. For example, aggregate invasive growth required cellular contacts mediated by the flocculin Flo11p, which was produced at higher levels in aggregates than cells undergoing regular invasive growth. Aggregate invasive growth was also stimulated by secreted enzymes, like invertase, which produce metabolites that are shared among cells. Aggregate invasive growth was also induced by alcohols that promote density-dependent filamentous growth in yeast. Aggregate invasive growth also required highly polarized cell morphologies, which may affect the packing or organization of cells. A directed selection experiment for aggregating phenotypes uncovered roles for the fMAPK and RAS pathways, which indicates that these pathways play a general role in regulating aggregate-based responses in yeast. Our study extends the range of responses controlled by filamentation regulatory pathways and has implications in understanding aspects of fungal biology that may be relevant to fungal pathogenesis. IMPORTANCE Filamentous growth is a fungal morphogenetic response that is critical for virulence in some fungal species. Many aspects of filamentous growth remain poorly understood. We have identified an aspect of filamentous growth in the budding yeast Saccharomyces cerevisiae and the human pathogen Candida albicans where cells behave collectively to invade surfaces in aggregates. These responses may reflect an extension of normal filamentous growth, as they share the same signaling pathways and effector processes. Aggregate responses may involve cooperation among individual cells, because aggregation was stimulated by cell adhesion molecules, secreted enzymes, and diffusible molecules that promote quorum sensing. Our study may provide insights into the genetic basis of collective cellular responses in fungi. The study may have ramifications in fungal pathogenesis, in situations where collective responses occur to promote virulence.
- Published
- 2019
- Full Text
- View/download PDF
5. Vertical Dynamic Deflection Measurement in Concrete Beams with the Microsoft Kinect
- Author
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Xiaojuan Qi, Derek Lichti, Mamdouh El-Badry, Jacky Chow, and Kathleen Ang
- Subjects
Microsoft Kinect ,quantization error ,structural deflection measurement ,Chemical technology ,TP1-1185 - Abstract
The Microsoft Kinect is arguably the most popular RGB-D camera currently on the market, partially due to its low cost. It offers many advantages for the measurement of dynamic phenomena since it can directly measure three-dimensional coordinates of objects at video frame rate using a single sensor. This paper presents the results of an investigation into the development of a Microsoft Kinect-based system for measuring the deflection of reinforced concrete beams subjected to cyclic loads. New segmentation methods for object extraction from the Kinect’s depth imagery and vertical displacement reconstruction algorithms have been developed and implemented to reconstruct the time-dependent displacement of concrete beams tested in laboratory conditions. The results demonstrate that the amplitude and frequency of the vertical displacements can be reconstructed with submillimetre and milliHz-level precision and accuracy, respectively.
- Published
- 2014
- Full Text
- View/download PDF
6. Impact of Fungal MAPK Pathway Targets on the Cell Wall
- Author
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Jacky Chow, Marysa Notaro, Aditi Prabhakar, Stephen J. Free, and Paul J. Cullen
- Subjects
cell wall ,mannoproteins ,cell–cell interactions ,cell wall stress ,MAPK ,Biology (General) ,QH301-705.5 - Abstract
The fungal cell wall is an extracellular organelle that provides structure and protection to cells. The cell wall also influences the interactions of cells with each other and surfaces. The cell wall can be reorganized in response to changing environmental conditions and different types of stress. Signaling pathways control the remodeling of the cell wall through target proteins that are in many cases not well defined. The Mitogen Activated Protein Kinase pathway that controls filamentous growth in yeast (fMAPK) was required for normal growth in media containing the cell wall perturbing agent Calcofluor White (CFW). A mass spectrometry (MASS-SPEC) approach and analysis of expression profiling data identified cell wall proteins and modifying enzymes whose levels were influenced by the fMAPK pathway. These include Flo11p, Flo10p, Tip1p, Pry2p and the mannosyltransferase, Och1p. Cells lacking Flo11p or Och1p were sensitive to CFW. The identification of cell wall proteins controlled by a MAPK pathway may provide insights into how signaling pathways regulate the cell wall.
- Published
- 2018
- Full Text
- View/download PDF
7. Alternative Methodologies for LiDAR System Calibration
- Author
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Jacky Chow, Ana Paula Kersting, Ki In Bang, and Ayman Habib
- Subjects
LiDAR ,system calibration ,accuracy ,error analysis ,Science - Abstract
Over the last few years, LiDAR has become a popular technology for the direct acquisition of topographic information. In spite of the increasing utilization of this technology in several applications, its accuracy potential has not been fully explored. Most of current LiDAR calibration techniques are based on empirical and proprietary procedures that demand the system’s raw measurements, which may not be always available to the end-user. As a result, we can still observe systematic discrepancies between conjugate surface elements in overlapping LiDAR strips. In this paper, two alternative calibration procedures that overcome the existing limitations are introduced. The first procedure, denoted as “Simplified method”, makes use of the LiDAR point cloud from parallel LiDAR strips acquired by a steady platform (e.g., fixed wing aircraft) over an area with moderately varying elevation. The second procedure, denoted as “Quasi-rigorous method”, can deal with non-parallel strips, but requires time-tagged LiDAR point cloud and navigation data (trajectory position only) acquired by a steady platform. With the widespread adoption of LAS format and easy access to trajectory information, this data requirement is not a problem. The proposed methods can be applied in any type of terrain coverage without the need for control surfaces and are relatively easy to implement. Therefore, they can be used in every flight mission if needed. Besides, the proposed procedures require minimal interaction from the user, which can be completely eliminated after minor extension of the suggested procedure.
- Published
- 2010
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8. Editor’s Corner: May 2023
- Author
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Michael Patlas and Jacky Chow
- Subjects
Radiology, Nuclear Medicine and imaging ,General Medicine - Published
- 2022
- Full Text
- View/download PDF
9. Immune Cell Molecular Pharmacodynamics of Lanreotide in Relation to Treatment Response
- Author
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Sabah Alaklabi, Orla Maguire, Yali Zhang, Jacky Chow, Jiamin Wang, Hans Minderman, and Renuka Iyer
- Published
- 2023
- Full Text
- View/download PDF
10. 778 Botensilimab, a novel innate/adaptive immune activator, plus or minus balstilimab (anti-PD-1) in 'cold' and I-O refractory metastatic solid tumors
- Author
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Breelyn Wilky, Anthony El-Khoueiry, Andrea Bullock, Apostolia Tsimberidou, Daruka Mahadevan, Kim Margolin, Jonathan Trent, Bruno Bockorny, Justin Moser, Peter Hosein, Marwan Fakih, Benjamin Schlecter, Jacob Thomas, Ani Balmanoukian, Rachel Sanborn, Ghassan Abou-Alfa, Gary Schwartz, Diana Hanna, Waldo Ortuzar Feliu, Joseph Grossman, Katherine Rosenthal, James Godwin, Jaymin Patel, Bonnie Bullock, Justin Stebbing, Bhupendra Rawal, Hunter Cole, Chloe Delepine, Jacky Chow, Ross Walker, Chris MacDermaid, Dhan Chand, Michael Gordon, Heinz-Josef Lenz, and Steven O’Day
- Published
- 2022
- Full Text
- View/download PDF
11. 470 Botensilimab, an Fc-enhanced CTLA-4 antibody, enhances innate and adaptive immune activation to promote superior anti-tumor immunity in cold and I-O refractory tumors
- Author
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Chloe Delepine, Daniel Levey, Shanmugarajan Krishnan, Kwang-Soo Kim, Adam Sonabend, Margaret Wilkens, Antoine Tanne, Pilar Garcia-Brocano, Claire Galand, Haiyong Han, Christopher MacDermaid, Jacky Chow, Sylvia Vincent, Shalu Karkwal, Yan Sun, Racehl Smith, Xavier Michelet, Kah Teong, Katherine Rosenthal, David Savitsky, Cailin Joyce, Steven O'Day, Joseph Grossman, Jaymin Patel, and Dhan Chand
- Published
- 2022
- Full Text
- View/download PDF
12. 941 Botensilimab modulates innate and adaptive gene expression programs resulting in superior immune stimulation relative to a first-generation anti-CTLA-4 antibody
- Author
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Shanmugarajan Krishnan, Jacky Chow, Kah Teong Soh, Kayla Ostergard, Christopher MacDermaid, Marc Van Dijk, Dennis Underwood, Dhan Chand, and Cailin Joyce
- Published
- 2022
- Full Text
- View/download PDF
13. Tumor and immune remodeling following radiotherapy in human renal cell carcinoma
- Author
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Jacky Chow, Adil Khan, Madeline Gaudieri, Brianna J Wasik, Alexis Conway, Kah Teong Soh, Elizabeth A Repasky, Thomas Schwaab, Paul K Wallace, Scott I Abrams, Anurag K Singh, and Jason B Muhitch
- Subjects
Pharmacology ,Cancer Research ,Oncology ,Immunology ,Molecular Medicine ,Immunology and Allergy - Abstract
BackgroundStudies evaluating peripheral patient samples show radiation can modulate immune responses, yet the biological changes in human tumors particularly at the cellular level remain largely unknown. Here, we address how radiation treatment shapes the immune compartment and interactions with cancer cells within renal cell carcinoma (RCC) patient tumors.MethodsTo identify how radiation shaped the immune compartment and potential immune interactions with tumor cells we evaluated RCC tumors from patients treated only with nephrectomy or with radiation followed by nephrectomy. Spectral flow cytometry using a 35-marker panel was performed on cell suspensions to evaluate protein expression within immune subsets. To reveal how radiation alters programming of immune populations and interactions with tumor cells, we examined transcriptional changes by single-cell RNA sequencing (scRNAseq).ResultsSpectral flow cytometry analysis revealed increased levels of early-activated as well as effector programmed cell death protein-1 (PD-1)+CD8 T-cell subsets within irradiated tumors. Following quality control, scRNAseq of tumor samples from nephrectomy-only or radiation followed by nephrectomy-treated patients generated an atlas containing 34,626 total cells. Transcriptional analysis revealed increased transition from stem-like T-cell populations to effector T cells in irradiated tumors. Interferon (IFN) pathways, that are central to radiation-induced immunogenicity, were enriched in irradiated lymphoid, myeloid, and cancer cell populations. Focused cancer cell analysis showed enhanced antigen presentation and increased predicted TRAIL-mediated and IFN-mediated interactions between tumor cells and the same effector T-cell subsets increased by radiation. TRAIL and IFN pathways enriched in irradiated tumors were associated with survival in patients treated with immunotherapy.ConclusionsThese findings identify the source of IFN enrichment within irradiated RCC and reveal heightened levels of PD-1+CD8+T-cell subsets and increased probability of interactions with tumor cells following standalone radiation treatment. This study provides a window into the irradiated tumor-immune microenvironment of patients and rationale for treatment combinations.
- Published
- 2023
- Full Text
- View/download PDF
14. Radiation induces dynamic changes to the T cell repertoire in renal cell carcinoma patients
- Author
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Nicholas C. Hoffend, Thomas Schwaab, Jason B. Muhitch, Scott I. Abrams, Anurag K. Singh, and Jacky Chow
- Subjects
Male ,renal cell carcinoma ,T-Lymphocytes ,T cell ,medicine.medical_treatment ,Cell ,Receptors, Antigen, T-Cell ,Radiosurgery ,Immunology and Inflammation ,Immune system ,Renal cell carcinoma ,Tumor Microenvironment ,medicine ,Humans ,Carcinoma, Renal Cell ,Aged ,Tumor microenvironment ,Multidisciplinary ,business.industry ,T-cell receptor ,RNA sequencing ,Immunotherapy ,Middle Aged ,Biological Sciences ,medicine.disease ,Kidney Neoplasms ,radiation ,Radiation therapy ,medicine.anatomical_structure ,Cancer research ,Female ,Transcriptome ,business ,T cell repertoire - Abstract
Significance Strong evidence supports the tumor immune landscape as a determinant of patient responses to immunotherapy. Readily available therapies, including radiation, are being investigated as modifying agents with immune checkpoint blockade. However, little is known regarding radiotherapy’s impact within the tumor microenvironment and intratumoral T cell repertoires of patients, leaving critical gaps in the guided design of clinical protocols. In this study, samples from renal cell carcinoma (RCC) patients underwent high-throughput analysis to reveal transcriptional immune activation and increased clonality in irradiated tumors. Analysis across longitudinal blood samples showed that tumor-enriched clonotypes undergo phases of peripheral expansion and contraction following radiation. Collectively, these findings demonstrate that radiotherapy remodels intratumoral T cell responses and support refined sequencing of combination strategies in RCC., Clinical studies combining radiation and immunotherapy have shown promising response rates, strengthening efforts to sensitize tumors to immune-mediated attack. Thus, there is an ongoing surge in trials using preconditioning regimens with immunotherapy. Yet, due to the scarcity of resected tumors treated in situ with radiotherapy, there has been little investigation of radiation’s sole contributions to local and systemic antitumor immunity in patients. Without this access, translational studies have been limited to evaluating circulating immune subsets and systemic remodeling of peripheral T cell receptor repertoires. This constraint has left gaps in how radiation impacts intratumoral responses and whether tumor-resident T cell clones are amplified following treatment. Therefore, to interrogate the immune impact of radiation on the tumor microenvironment and test the hypothesis that radiation initiates local and systemic expansion of tumor-resident clones, we analyzed renal cell carcinomas from patients treated with stereotactic body radiation therapy. Transcriptomic comparisons were evaluated by bulk RNA sequencing. T cell receptor sequencing monitored repertoires during treatment. Pathway analysis showed radiation-specific enrichment of immune-related processes, and T cell receptor sequencing revealed increased clonality in radiation-treated tumors. The frequency of identified, tumor-enriched clonotypes was tracked across serial blood samples. We observed increased abundance of tumor-enriched clonotypes at 2 wk postradiation compared with pretreatment levels; however, this expansion was not sustained, and levels contracted toward baseline by 4 wk posttreatment. Taken together, these results indicate robust intratumoral immune remodeling and a window of tumor-resident T cell expansion following radiation that may be leveraged for the rational design of combinatorial strategies.
- Published
- 2020
- Full Text
- View/download PDF
15. Quantitative analysis of diaphragm motion during fluoroscopic sniff test to assist in diagnosis of hemidiaphragm paralysis
- Author
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Jacky Chow and Muhammed Hatem
- Subjects
Image and Video Processing (eess.IV) ,FOS: Electrical engineering, electronic engineering, information engineering ,FOS: Physical sciences ,Radiology, Nuclear Medicine and imaging ,Medical Physics (physics.med-ph) ,Electrical Engineering and Systems Science - Image and Video Processing ,musculoskeletal system ,Physics - Medical Physics - Abstract
The current imaging gold standard for detecting paradoxical diaphragm motion and diagnosing hemidiaphragm paralysis is to perform the fluoroscopic sniff test. The images are visually examined by an experienced radiologist, and if one hemidiaphragm ascends while the other descends, then it is described as paradoxical motion, which is highly suggestive of hemidiaphragm paralysis. However, diagnosis can be challenging because diaphragm motion during sniffing is fast, paradoxical motion can be subtle, and the analysis is based on a 2-dimensional projection of a 3-dimensional surface. This paper presents a case of chronic left hemidiaphragm elevation that was initially reported as mild paradoxical motion on fluoroscopy. After measuring the elevations of the diaphragms and modeling their temporal correlation using Gaussian process regression, the systematic trend of the hemidiaphragmatic motion along with its stochastic properties was determined. When analyzing the trajectories of the hemidiaphragms, no statistically significant paradoxical motion was detected. This could potentially change the prognosis if the patient was to consider diaphragm plication as treatment. The presented method provides a more objective analysis of hemidiaphragm motions and can potentially improve diagnostic accuracy.
- Published
- 2022
- Full Text
- View/download PDF
16. Editor’s Corner: August 2023
- Author
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Michael Patlas and Jacky Chow
- Subjects
Radiology, Nuclear Medicine and imaging ,General Medicine - Published
- 2023
- Full Text
- View/download PDF
17. MP39-18 AN AUTOCHTHONOUS MOUSE MODEL OF KIDNEY CANCER WITH T CELL INFILTRATION
- Author
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Bo Xu, Nitika Sharma, Jason B. Muhitch, Eric Kauffman, and Jacky Chow
- Subjects
business.industry ,Renal cell carcinoma ,Urology ,T cell infiltration ,Cancer research ,medicine ,urologic and male genital diseases ,medicine.disease ,business ,Kidney cancer - Abstract
INTRODUCTION AND OBJECTIVE:Immunocompetent animal models that recapitulate human renal cell carcinoma (RCC) and its tumor-immune microenvironment are critical for the preclinical study of novel imm...
- Published
- 2021
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18. Filamentation Regulatory Pathways Control Adhesion-Dependent Surface Responses in Yeast
- Author
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Izzy Starr, Denise M. Ferkey, Paul J. Cullen, Anuj Kumar, Omer Gokcumen, Omar Muniz, Jacky Chow, and Sheida Jamalzadeh
- Subjects
MAPK/ERK pathway ,Saccharomyces cerevisiae Proteins ,MAP Kinase Signaling System ,Hyphae ,Saccharomyces cerevisiae ,Protein Serine-Threonine Kinases ,Investigations ,Biology ,Histone Deacetylases ,Chromatin remodeling ,03 medical and health sciences ,Pseudohyphal growth ,Gene Expression Regulation, Fungal ,Cell Adhesion ,Genetics ,Transcriptional regulation ,Cell adhesion ,Gene ,030304 developmental biology ,0303 health sciences ,Membrane Glycoproteins ,Virulence ,030306 microbiology ,Cyclin-Dependent Kinases ,Cell biology ,Repressor Proteins ,Gene expression profiling ,Biofilms ,Trans-Activators ,ras Proteins ,Signal transduction - Abstract
Signaling pathways can regulate biological responses by the transcriptional regulation of target genes. In yeast, multiple signaling pathways control filamentous growth, a morphogenetic response that occurs in many species including fungal pathogens. Here, we examine the role of signaling pathways that control filamentous growth in regulating adhesion-dependent surface responses, including mat formation and colony patterning. Expression profiling and mutant phenotype analysis showed that the major pathways that regulate filamentous growth [filamentous growth MAPK (fMAPK), RAS, retrograde (RTG), RIM101, RPD3, ELP, SNF1, and PHO85] also regulated mat formation and colony patterning. The chromatin remodeling complex, SAGA, also regulated these responses. We also show that the RAS and RTG pathways coregulated a common set of target genes, and that SAGA regulated target genes known to be controlled by the fMAPK, RAS, and RTG pathways. Analysis of surface growth-specific targets identified genes that respond to low oxygen, high temperature, and desiccation stresses. We also explore the question of why cells make adhesive contacts in colonies. Cell adhesion contacts mediated by the coregulated target and adhesion molecule, Flo11p, deterred entry into colonies by macroscopic predators and impacted colony temperature regulation. The identification of new regulators (e.g., SAGA), and targets of surface growth in yeast may provide insights into fungal pathogenesis in settings where surface growth and adhesion contributes to virulence.
- Published
- 2019
- Full Text
- View/download PDF
19. CRISPR Gene Editing in Yeast: An Experimental Protocol for an Upper-Division Undergraduate Laboratory Course
- Author
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Nitasha Sehgal, M. Eileen Sylves, Jacky Chow, James O. Berry, Ansuman Sahoo, Paul J. Cullen, and Sarah E. Walker
- Subjects
0301 basic medicine ,biology ,ved/biology ,05 social sciences ,Saccharomyces cerevisiae ,ved/biology.organism_classification_rank.species ,050301 education ,Computational biology ,biology.organism_classification ,Biochemistry ,Homology directed repair ,03 medical and health sciences ,030104 developmental biology ,Genome editing ,CRISPR ,Identification (biology) ,Guide RNA ,Model organism ,0503 education ,Molecular Biology ,Gene - Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) are a revolutionary tool based on a bacterial acquired immune response system. CRISPR has gained widespread use for gene editing in a variety of organisms and is an increasingly valuable tool for basic genetic research, with far-reaching implications for medicine, agriculture, and industry. This lab is based on the premise that upper division undergraduate students enrolled in a Life Sciences curriculum must become familiar with cutting edge advances in biotechnology that have significant impact on society. Toward this goal, we developed a new hands-on laboratory exercise incorporating the use of CRISPR-Cas9 and homology directed repair (HDR) to edit two well-characterized genes in the budding yeast, Saccharomyces cerevisiae. The two genes edited in this exercise, Adenine2 (ADE2) and Sterile12 (STE12) affect metabolic and developmental processes, respectively. Editing the premature stop codons in these genes results in clearly identifiable phenotypes that can be assessed by students in a standard laboratory course setting. Making use of this basic eukaryotic model organism facilitates a laboratory exercise that is inexpensive, simple to organize, set up, and present to students. This exercise enables undergraduate students to initiate and follow-up on all stages of the CRISPR gene editing process, from identification of guide RNAs, amplification of an appropriate HDR fragment, and analysis of mutant phenotypes. The organization of this protocol also allows for easy modification, providing additional options for editing any expressed genes within the yeast genome to produce new mutations, or recovery of existing mutants to wild type. © 2018 International Union of Biochemistry and Molecular Biology, 46(6):592-601, 2018.
- Published
- 2018
- Full Text
- View/download PDF
20. Aggregate Filamentous Growth Responses in Yeast
- Author
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Aditi Prabhakar, Beatriz González, Paul J. Cullen, Mira Edgerton, Jacky Chow, Jenn Somboonthum, Amit Mehrotra, and Heather Dionne
- Subjects
rho GTP-Binding Proteins ,Cell type ,Molecular Biology and Physiology ,fungal morphogenesis ,MAP Kinase Signaling System ,Cellular differentiation ,Saccharomyces cerevisiae ,lcsh:QR1-502 ,Virulence ,Biology ,Microbiology ,cell shape ,lcsh:Microbiology ,03 medical and health sciences ,quasisociality ,Gene Expression Regulation, Fungal ,Candida albicans ,Molecular Biology ,030304 developmental biology ,2. Zero hunger ,0303 health sciences ,fungal pathogenesis ,030306 microbiology ,Effector ,Rho GTPase ,biology.organism_classification ,Yeast ,QR1-502 ,Cell biology ,Quorum sensing ,cell differentiation ,cell polarity ,Alcohols ,MAP kinase ,collective cellular responses ,Research Article ,Signal Transduction - Abstract
Filamentous growth is a fungal morphogenetic response that is critical for virulence in some fungal species. Many aspects of filamentous growth remain poorly understood. We have identified an aspect of filamentous growth in the budding yeast Saccharomyces cerevisiae and the human pathogen Candida albicans where cells behave collectively to invade surfaces in aggregates. These responses may reflect an extension of normal filamentous growth, as they share the same signaling pathways and effector processes. Aggregate responses may involve cooperation among individual cells, because aggregation was stimulated by cell adhesion molecules, secreted enzymes, and diffusible molecules that promote quorum sensing. Our study may provide insights into the genetic basis of collective cellular responses in fungi. The study may have ramifications in fungal pathogenesis, in situations where collective responses occur to promote virulence., Many fungal species, including pathogens, undergo a morphogenetic response called filamentous growth, where cells differentiate into a specialized cell type to promote nutrient foraging and surface colonization. Despite the fact that filamentous growth is required for virulence in some plant and animal pathogens, certain aspects of this behavior remain poorly understood. By examining filamentous growth in the budding yeast Saccharomyces cerevisiae and the opportunistic pathogen Candida albicans, we identify responses where cells undergo filamentous growth in groups of cells or aggregates. In S. cerevisiae, aggregate invasive growth was regulated by signaling pathways that control normal filamentous growth. These pathways promoted aggregation in part by fostering aspects of microbial cooperation. For example, aggregate invasive growth required cellular contacts mediated by the flocculin Flo11p, which was produced at higher levels in aggregates than cells undergoing regular invasive growth. Aggregate invasive growth was also stimulated by secreted enzymes, like invertase, which produce metabolites that are shared among cells. Aggregate invasive growth was also induced by alcohols that promote density-dependent filamentous growth in yeast. Aggregate invasive growth also required highly polarized cell morphologies, which may affect the packing or organization of cells. A directed selection experiment for aggregating phenotypes uncovered roles for the fMAPK and RAS pathways, which indicates that these pathways play a general role in regulating aggregate-based responses in yeast. Our study extends the range of responses controlled by filamentation regulatory pathways and has implications in understanding aspects of fungal biology that may be relevant to fungal pathogenesis. IMPORTANCE Filamentous growth is a fungal morphogenetic response that is critical for virulence in some fungal species. Many aspects of filamentous growth remain poorly understood. We have identified an aspect of filamentous growth in the budding yeast Saccharomyces cerevisiae and the human pathogen Candida albicans where cells behave collectively to invade surfaces in aggregates. These responses may reflect an extension of normal filamentous growth, as they share the same signaling pathways and effector processes. Aggregate responses may involve cooperation among individual cells, because aggregation was stimulated by cell adhesion molecules, secreted enzymes, and diffusible molecules that promote quorum sensing. Our study may provide insights into the genetic basis of collective cellular responses in fungi. The study may have ramifications in fungal pathogenesis, in situations where collective responses occur to promote virulence.
- Published
- 2019
21. Abstract PO-038: Hide and Seq: Radiation-induced immunogenicity of patient tumors revealed by single cell analysis
- Author
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Nicholas C. Hoffend, Jacky Chow, Anurag K. Singh, Scott I. Abrams, Madeline Gaudieri, Jason B. Muhitch, and Thomas Schwaab
- Subjects
Cancer Research ,Oncology ,Single-cell analysis ,Chemistry ,Immunogenicity ,Cancer research ,Radiation induced - Abstract
Robust preclinical investigations into radiation-induced immunogenicity has led to increased enthusiasm for combining radiation with immunotherapy. Promising results in a limited number of patients treated with radiotherapy and immune-activating strategies has supported the initiation of over 150 ongoing clinical trials. Yet, due to reduced availability of patient samples following treatment, tumor tissue in particular, there has been sparse investigation of the impact of radiation on immunogenicity in human malignancies. While murine models have revealed important insights into understanding radiation-induced immunogenic mechanisms, inherent differences in radiation sensitivity between mice and humans limit translation to patients. To determine the impact of radiation on patient tumor cells we analyzed samples from renal cell carcinoma (RCC) patients treated with stereotactic body radiation therapy (SBRT) in a pilot study (NCT01892930). Previous data showed radiation induced surface presentation of tumor-associated antigens in resected irradiated tumors. Bulk transcriptomic data of in situ-irradiated tumors showed evidence of immune activation, including increased interferon-gamma (IFNG) signaling, as well as increased T cell clonality and higher abundance of T cells clones with similar binding affinities predicted by dominant motif analysis. We hypothesized that the tumor response to in situ irradiation included increased transcript abundance for tumor antigen genes and antigen-presentation machinery, as well as a response to IFNG signaling. Tumor cell comparisons following single-cell RNA sequencing uncovered RCC cell-specific responses to in situ irradiation. Irradiated RCC tumor cells expressed higher levels of genes encoding MUC-1 and carbonic anhydrase 9, as well as higher expression of calreticulin and genes encoding MHC class 1 molecules: HLA-A, HLA-B, and HLA-C; furthermore, gene set enrichment identified enhancement of antigen processing and presentation pathways. Additionally, irradiated tumor cells expressed higher levels of the IFNG receptor, its downstream targets, and the enrichment of several interferon response gene sets. Collectively, these results indicate radiation may improve tumor recognition through both increased antigen expression and surface presentation as well as sensitize tumor cells to immunogenic cytokines and T cell-mediated cytolysis in human malignancies, such as RCC. Citation Format: Jacky L. Chow, Nicholas Hoffend, Madeline Gaudieri, Scott Abrams, Thomas Schwaab, Anurag Singh, Jason Muhitch. Hide and Seq: Radiation-induced immunogenicity of patient tumors revealed by single cell analysis [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-038.
- Published
- 2021
- Full Text
- View/download PDF
22. CRISPR Gene Editing in Yeast: An Experimental Protocol for an Upper-Division Undergraduate Laboratory Course
- Author
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Nitasha, Sehgal, M Eileen, Sylves, Ansuman, Sahoo, Jacky, Chow, Sarah E, Walker, Paul J, Cullen, and James O, Berry
- Subjects
Gene Editing ,Universities ,Genetics ,Clustered Regularly Interspaced Short Palindromic Repeats ,Curriculum ,Saccharomyces cerevisiae ,Laboratories ,Students ,Article - Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR) are a revolutionary tool based on a bacterial acquired immune response system. CRISPR has gained widespread use for gene editing in a variety of organisms and is an increasingly valuable tool for basic genetic research, with far-reaching implications for medicine, agriculture, and industry. This lab is based on the premise that upper division undergraduate students enrolled in a Life Sciences curriculum must become familiar with cutting edge advances in biotechnology that have significant impact on society. Toward this goal, we developed a new hands-on laboratory exercise incorporating the use of CRISPR-Cas9 and homology directed repair (HDR) to edit two well-characterized genes in the budding yeast, Saccharomyces cerevisiae. The two genes edited in this exercise, Adenine2 (ADE2) and Sterile12 (STE12) affect metabolic and developmental processes, respectively. Editing the premature stop codons in these genes results in clearly identifiable phenotypes that can be assessed by students in a standard laboratory course setting. Making use of this basic eukaryotic model organism facilitates a laboratory exercise that is inexpensive, simple to organize, set up, and present to students. This exercise enables undergraduate students to initiate and follow-up on all stages of the CRISPR gene editing process, from identification of guide RNAs, amplification of an appropriate HDR fragment, and analysis of mutant phenotypes. The organization of this protocol also allows for easy modification, providing additional options for editing any expressed genes within the yeast genome to produce new mutations, or recovery of existing mutants to wild type. © 2018 International Union of Biochemistry and Molecular Biology, 46(6):592-601, 2018.
- Published
- 2018
23. A coupled cantilever-microelectrode biosensor for enhanced pathogen detection
- Author
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Aristides Docoslis, Yongjun Lai, Matthew R. Tomkins, and Jacky Chow
- Subjects
Cantilever ,Pathogen detection ,Materials science ,business.industry ,Metals and Alloys ,Nanotechnology ,Dielectrophoresis ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Microelectrode ,Electrokinetic phenomena ,Sampling (signal processing) ,Materials Chemistry ,Optoelectronics ,Electrical and Electronic Engineering ,business ,Instrumentation ,Sensitivity (electronics) ,Biosensor - Abstract
A pathogen detection platform that integrates electrokinetically accelerated sampling with electromechanical signal transduction is presented. Detection of pathogens without the need for cultivation is achieved by employing a prototype device that combines microelectrodes embedded directly onto the surface of a cantilever beam. Escherichia coli bacteria captured on the surface of the cantilever with the aid of AC electrokinetic effects (dielectrophoresis) within 30 min of sampling time were found to cause substantial resonant frequency shifts compared to unassisted capture. The effect of the cantilever's resonant mode was also examined in order to identify conditions that can improve detection sensitivity.
- Published
- 2013
- Full Text
- View/download PDF
24. Displacement sensing of a micro-electro-thermal actuator using a monolithically integrated thermal sensor
- Author
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Yongjun Lai and Jacky Chow
- Subjects
Thermal sensors ,Materials science ,business.industry ,Metals and Alloys ,Process (computing) ,Linearity ,Condensed Matter Physics ,Displacement (vector) ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Thermal ,Electronic engineering ,Optoelectronics ,Sensitivity (control systems) ,Electrical and Electronic Engineering ,Actuator ,business ,Instrumentation - Abstract
The present paper describes a novel concept that employs a thermal-based approach for in-situ displacement sensing of electro-thermal actuators. A device encompassing an in-plane electro-thermal actuator and a thermal sensor was monolithically fabricated using the MetalMUMPS process. Analytical models were developed for both the actuator and the thermal sensor. Simulation and experimental results demonstrated good agreement. The experimental results indicated that the sensor achieved high linearity and sensitivity (∼4.5 nm/Ω).
- Published
- 2009
- Full Text
- View/download PDF
25. Increased stability of microtubules in cultured olfactory neuroepithelial cells from individuals with schizophrenia
- Author
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J. Chloë Bulinski, Yuanyuan Bao, Thelma McCloskey, Raquel E. Gur, Patric Prado, Lorna W. Role, Andrew J. Dwork, Karin E. Borgmann-Winter, Alan S. Brown, David A. Talmage, Chang-Gyu Hahn, and Jacky Chow
- Subjects
Pharmacology ,medicine.medical_specialty ,Pathology ,Cell type ,biology ,medicine.medical_treatment ,Central nervous system ,Hippocampus ,medicine.disease ,Olfactory bulb ,Neuroepithelial cell ,DISC1 ,Endocrinology ,medicine.anatomical_structure ,Schizophrenia ,Internal medicine ,medicine ,biology.protein ,Antipsychotic ,Biological Psychiatry - Abstract
Microtubules (MTs) are essential components of the cytoskeleton that play critical roles in neurodevelopment and adaptive central nervous system functioning. MTs are essential to growth cone advance and ultrastructural events integral to synaptic plasticity; these functions figure significantly into current pathophysiologic conceptualizations of schizophrenia. To date, no study has directly investigated MT dynamics in humans with schizophrenia. We therefore compared the stability of MTs in olfactory neuroepithelial (OE) cells between schizophrenia cases and matched nonpsychiatric comparison subjects. For this purpose, we applied nocodazole (Nz) to cultured OE cells obtained from tissue biopsies from seven living schizophrenia patients and seven matched comparison subjects; all schizophrenia cases were on antipsychotic medications. Nz allows MT depolymerization to be followed but prevents repolymerization, so that in living cells treated for varying time intervals, the MTs that are stable for a given treatment interval remain. Our readout of MT stability was the time at which fewer than 10 MTs per cell could be distinguished by anti-β-tubulin immunofluorescence. The percentage of cells with ≥ 10 intact MTs at specified intervals following Nz treatment was estimated by systematic uniform random sampling with Visiopharm software. These analyses showed that the mean percentages of OE cells with intact MTs were significantly greater for schizophrenia cases than for the matched comparison subjects at 10, 15, and 30 min following Nz treatment indicating increased MT stability in OE cells from schizophrenia patients (p = 0.0007 at 10 min; p = 0.0008 at 15 min; p = 0.036 at 30 min). In conclusion, we have demonstrated increased MT stability in nearly all cultures of OE cells from individuals with schizophrenia, who received several antipsychotic treatments, versus comparison subjects matched for age and sex. While we cannot rule out a possible confounding effect of antipsychotic medications, these findings may reflect analogous neurobiological events in at least a subset of immature neurons or other cell types during gestation, or newly generated cells destined for the olfactory bulb or hippocampus, suggesting a mechanism that underlies findings of postmortem and neuroimaging investigations of schizophrenia. Future studies aimed at replicating these findings, including samples of medication-naive subjects with schizophrenia, and reconciling the results with other studies, will be necessary. Although the observed abnormalities may suggest one of a number of putative pathophysiologic anomalies in schizophrenia, this work may ultimately have implications for an improved understanding of pathogenic processes related to this disorder.
- Published
- 2013
26. Improvements to and Comparison of Static Terrestrial LiDAR Self-Calibration Methods
- Author
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Hartzell, Jacky Chow, Derek Lichti, Craig Glennie, and Preston
- Subjects
LiDAR ,terrestrial laser scanners ,calibration ,accuracy ,error analysis ,quality assurance - Abstract
Terrestrial laser scanners are sophisticated instruments that operate much like high-speed total stations. It has previously been shown that unmodelled systematic errors can exist in modern terrestrial laser scanners that deteriorate their geometric measurement precision and accuracy. Typically, signalised targets are used in point-based self-calibrations to identify and model the systematic errors. Although this method has proven its effectiveness, a large quantity of signalised targets is required and is therefore labour-intensive and limits its practicality. In recent years, feature-based self-calibration of aerial, mobile terrestrial, and static terrestrial laser scanning systems has been demonstrated. In this paper, the commonalities and differences between point-based and plane-based self-calibration (in terms of model identification and parameter correlation) are explored. The results of this research indicate that much of the knowledge from point-based self-calibration can be directly transferred to plane-based calibration and that the two calibration approaches are nearly equivalent. New network configurations, such as the inclusion of tilted scans, were also studied and prove to be an effective means for strengthening the self-calibration solution, and improved recoverability of the horizontal collimation axis error for hybrid scanners, which has always posed a challenge in the past.
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- 2013
- Full Text
- View/download PDF
27. Using an In-Situ Micromirror to Assist the Measurement of In-Plane Vibration of Microstructures
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Jacky Chow and Yongjun Lai
- Subjects
Heterodyne ,Materials science ,Cantilever ,business.industry ,Physics::Optics ,Laser ,Horizontal plane ,Focused ion beam ,Computer Science::Other ,law.invention ,Interferometry ,Surface micromachining ,Optics ,law ,Astronomical interferometer ,business - Abstract
Heterodyne laser interferometry is an optical technique often used to measure displacement of surfaces along the wave vector direction of a measurement laser. For common microelectromechanical system (MEMS) testing setup, such laser wave vector is perpendicular to the substrate which the micromachined devices stand on. Therefore, this technique can only be used to characterize dynamics of the micro devices in the direction perpendicular to their substrate (out-of-plane motions) with the classic setup and it is not able to measure any motion that is parallel to the substrate (in-plane motions). In this study, in-situ micromirrors are fabricated onto a microstructure that is near the device to be measured by using a focused ion beam system. The micromirrors have a slant angle of approximate 45 degree to horizontal surface (or their substrate). By using the post-fabricated in-situ micromirror, the measurement laser of a heterodyne interferometer can be directed into horizontal plane which enables characterization of in-plane motions for micromechanical. To experimentally demonstrate the technique a micro cantilever fabricated using MetalMUMPs is used. The micro cantilever is excited by inplane electrostatic force. The results confirm the effectiveness of the method by the fact that the magnitude of the measured in-plane signal is increased by more than ten folds.Copyright © 2010 by ASME
- Published
- 2010
- Full Text
- View/download PDF
28. Mass measurement with micromechanical single harmonic oscillators
- Author
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Jacky Chow and Yongjun Lai
- Subjects
Physics ,Quantum electrodynamics ,Electronic engineering ,Parametric oscillator ,Mass measurement ,Harmonic oscillator - Published
- 2009
- Full Text
- View/download PDF
29. Poster #T34 INCREASED STABILITY OF MICROTUBULES IN CULTURED OLFACTORY NEUROEPITHELIAL CELLS FROM INDIVIDUALS WITH SCHIZOPHRENIA
- Author
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Patric Prado, Lorna W. Role, Andrew J. Dwork, Chang-Gyu Hahn, Jacky Chow, J. Chloë Bulinski, Raquel E. Gur, Alan Brown, Karin E. Borgmann-Winter, Thelma McCloskey, and David A. Talmage
- Subjects
Neuroepithelial cell ,Psychiatry and Mental health ,Microtubule ,Schizophrenia (object-oriented programming) ,Psychology ,Neuroscience ,Biological Psychiatry - Published
- 2014
- Full Text
- View/download PDF
30. Note: Exciting higher-order flexural modes of freestanding microstructures with square wave driving signals
- Author
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Jacky Chow and Yongjun Lai
- Subjects
Physics ,business.industry ,Frequency multiplier ,Acoustics ,Fundamental frequency ,Square wave ,Low frequency ,Optical heterodyne detection ,Square (algebra) ,Optics ,Harmonics ,Heterodyne detection ,business ,Instrumentation - Abstract
We examine using the harmonics of low fundamental frequency (f(1)) square waveforms to electrostatically excite higher-order flexural modes of a micromechanical structure in higher (f(1)) frequency regimes. Square wave signals swept between a fundamental frequency range of approximately 0-333 kHz demonstrated an effective high magnitude spectral excitation of approximately 0-1 MHz. This enabled optical heterodyne detection of structural resonant frequencies above 333 kHz. Low frequency square wave signals were also used to selectively excite modes at higher frequencies.
- Published
- 2010
- Full Text
- View/download PDF
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