Open Access. Powered by Scholars. Published by Universities.®

Biomedical Engineering and Bioengineering Commons

Open Access. Powered by Scholars. Published by Universities.®

University of Pennsylvania

Discipline
Keyword
Publication Year
Publication
Publication Type

Articles 1 - 30 of 134

Full-Text Articles in Biomedical Engineering and Bioengineering

Influence Of Naoh Concentration On Transfer Process Of Graphene, Francisco Saldana, Chengyu Wen, George Patrick Watson Sep 2019

Influence Of Naoh Concentration On Transfer Process Of Graphene, Francisco Saldana, Chengyu Wen, George Patrick Watson

Protocols and Reports

The process of transferring a monolayer of graphene using two different concentrations of sodium hydroxide (NaOH) solution unto a silicon dioxide (SiO2) coated Si chip using electrochemistry was performed. The transfer process is crucial for the delamination of a continuous graphene monolayer film from copper foil. After examining and inspecting the integrity of the graphene monolayer, it was observed that the lower concentration to NaOH led to slower rate of hydrogen bubble generation; this condition was found to be less destructive and yielded a graphene film with fewer visible tears.


Reactive Ion Etching Selectivity Of Si/Sio2: Comparing Of Two fluorocarbon Gases Chf3 And Cf4, Meiyue Zhang, Pat Watson Mar 2019

Reactive Ion Etching Selectivity Of Si/Sio2: Comparing Of Two fluorocarbon Gases Chf3 And Cf4, Meiyue Zhang, Pat Watson

Protocols and Reports

Two reactive ion etching (RIE) processes were studied to show the relative etch selectivity between SiO2 and Si using two fluorocarbon gases, CF4 and CHF3. Results show that CHF3 gives better selectivity (16:1) over CF4 (1.2 :1). On the other hand, the etch rate of SiO2 of CF4 is approximately 52.8 nm/min, faster than CHF3 (32.4 nm/min).


An Open-Source Plate Reader, Karol Szymula, Michael S. Magaraci, Michael Patterson, Andrew Clark, Sevile G. Mannickarottu, Brian Y. Chow Jan 2018

An Open-Source Plate Reader, Karol Szymula, Michael S. Magaraci, Michael Patterson, Andrew Clark, Sevile G. Mannickarottu, Brian Y. Chow

Departmental Papers (BE)

Microplate readers are foundational instruments in experimental biology and bioengineering that enable multiplexed spectrophotometric measurements. To enhance their accessibility, we here report the design, construction, validation, and benchmarking of an open-source microplate reader. The system features full-spectrum absorbance and fluorescence emission detection, in situ optogenetic stimulation, and stand-alone touch screen programming of automated assay protocols. The total system costs


Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 2, Ming Yuan Chuang May 2017

Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 2, Ming Yuan Chuang

Protocols and Reports

This report describes the rheological analysisof the present Ag nanoparticle ink, and confirms that it is suitable for the piezoelectric drop-on-demand printing for both of 1 pL and 10 pL cartridges. The satellite drops and the splashing on the substrate are also discussed for optimization of the nozzle temperature and the jetting voltage. The minimum horizontal and vertical line widths are shown to be 30 and 40 µm, respectively, but the average minimum single line width is estimated to be ~50 µm. The non-uniform width lines are suggested to arise from the bulge instability. Furthermore, it is indicated that the ...


Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 1, Amal Abbas, Inayat Bajwa Jan 2017

Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 1, Amal Abbas, Inayat Bajwa

Protocols and Reports

Ag nanoparticle inkjet printing on polyimide and polyethylene terephthalate films has been performed using Dimatix inkjet printer at Quattrone Nanofabrication Facility. This article describes selection of Ag nanoparticle inks and reports the progress of optimization of drop spacing, drop frequency, droplet size, and waveform for high resolution features, and furthermore reveals the pros and cons of Dimatix inkjet printing. In addition, the resistivity of Ag nanoparticle line sintered was determined to be ~2.2 x 10-5 Ωm. The adhesion and bending tests indicated that Ag nanoparticle pattern sintered on PI and PET films had exceptional mechanical stability.


Optogenetic Control Of Calcium Oscillation Waveform Defines Nfat As An Integrator Of Calcium Load, Pimkhuan Hannanta-Anan, Brian Y. Chow Apr 2016

Optogenetic Control Of Calcium Oscillation Waveform Defines Nfat As An Integrator Of Calcium Load, Pimkhuan Hannanta-Anan, Brian Y. Chow

Departmental Papers (BE)

It is known that the calcium-dependent transcription factor NFAT initiates transcription in response to pulsatile loads of calcium signal. However, the relative contributions of calcium oscillation frequency, amplitude, and duty cycle to transcriptional activity remain unclear. Here, we engineer HeLa cells to permit optogenetic control of intracellular calcium concentration using programmable LED arrays. This approach allows us to generate calcium oscillations of constant peak amplitude, in which frequency is varied while holding duty cycle constant, or vice versa. Using this setup and mathematical modeling, we show that NFAT transcriptional activity depends more on duty cycle, defined as the proportion of ...


Toolbox For Exploring Modular Gene Regulation In Synthetic Biology Training, Michael S. Magaraci, Jessica G. Bermudez, Deeksha Yogish, Daniel H. Pak, Viktor Mollov, Josh Tycko, David Issadore, Sevile G. Mannickarottu, Brian Y. Chow Jan 2016

Toolbox For Exploring Modular Gene Regulation In Synthetic Biology Training, Michael S. Magaraci, Jessica G. Bermudez, Deeksha Yogish, Daniel H. Pak, Viktor Mollov, Josh Tycko, David Issadore, Sevile G. Mannickarottu, Brian Y. Chow

Departmental Papers (BE)

We report a toolbox for exploring the modular tuning of genetic circuits, which has been specifically optimized for widespread deployment in STEM environments through a combination of bacterial strain engineering and distributable hardware development. The transfer functions of 16 genetic switches, programmed to express a GFP reporter under the regulation of the (acyl-homoserine lactone) AHL-sensitive luxR transcriptional activator, can be parametrically tuned by adjusting high/low degrees of transcriptional, translational, and post-translational processing. Strains were optimized to facilitate daily large-scale preparation and reliable performance at room temperature in order to eliminate the need for temperature controlled apparatuses, which are both ...


Persistently Altered Brain Mitochondrial Bioenergetics After Apparently Successful Resuscitation From Cardiac Arrest, Todd Kilbaugh, Robert M. Sutton, Michael Karlsson, Magnus J. Hansson, Maryam Y. Naim, Ryan W. Morgan, George Bratinov, Joshua Willard Lampe, Vinay Nadkarni, Lance Becker, Susan S. Margulies, Robert A. Berg Sep 2015

Persistently Altered Brain Mitochondrial Bioenergetics After Apparently Successful Resuscitation From Cardiac Arrest, Todd Kilbaugh, Robert M. Sutton, Michael Karlsson, Magnus J. Hansson, Maryam Y. Naim, Ryan W. Morgan, George Bratinov, Joshua Willard Lampe, Vinay Nadkarni, Lance Becker, Susan S. Margulies, Robert A. Berg

Departmental Papers (BE)

Background Although advances in cardiopulmonary resuscitation have improved survival from cardiac arrest (CA), neurologic injury persists and impaired mitochondrial bioenergetics may be critical for targeted neuroresuscitation. The authors sought to determine if excellent cardiopulmonary resuscitation and postresuscitation care and good traditional survival rates result in persistently disordered cerebral mitochondrial bioenergetics in a porcine pediatric model of asphyxia‐associated ventricular fibrillation CA.

Methods and Results After 7 minutes of asphyxia, followed by ventricular fibrillation, 5 female 1‐month‐old swine (4 sham) received blood pressure–targeted care: titration of compression depth to systolic blood pressure of 90 mm Hg and vasopressor ...


Peripheral Blood Mitochondrial Dna As A Biomarker Of Cerebral Mitochondrial Dysfunction Following Traumatic Brain Injury In A Porcine Model, Todd Kilbaugh, Maria Lvova, Michael Karlsson, Zhe Zhang, Jeremy Leipzig, Douglas C. Wallace, Susan S. Margulies Jun 2015

Peripheral Blood Mitochondrial Dna As A Biomarker Of Cerebral Mitochondrial Dysfunction Following Traumatic Brain Injury In A Porcine Model, Todd Kilbaugh, Maria Lvova, Michael Karlsson, Zhe Zhang, Jeremy Leipzig, Douglas C. Wallace, Susan S. Margulies

Departmental Papers (BE)

Background

Traumatic brain injury (TBI) has been shown to activate the peripheral innate immune system and systemic inflammatory response, possibly through the central release of damage associated molecular patterns (DAMPs). Our main purpose was to gain an initial understanding of the peripheral mitochondrial response following TBI, and how this response could be utilized to determine cerebral mitochondrial bioenergetics. We hypothesized that TBI would increase peripheral whole blood relative mtDNA copy number, and that these alterations would be associated with cerebral mitochondrial bioenergetics triggered by TBI.

Methodology

Blood samples were obtained before, 6 h after, and 25 h after focal (controlled ...


Establishing A Clinically Relevant Large Animal Model Platform For Tbi Therapy Development: Using Cyclosporin A As A Case Study, Susan S. Margulies, Todd Kilbaugh, Sarah Sullivan, Colin Smtih, Kathleen J. Propert, Melissa Byro, Kristen Saliga, Beth A. Costine, Ann-Christine Duhaime May 2015

Establishing A Clinically Relevant Large Animal Model Platform For Tbi Therapy Development: Using Cyclosporin A As A Case Study, Susan S. Margulies, Todd Kilbaugh, Sarah Sullivan, Colin Smtih, Kathleen J. Propert, Melissa Byro, Kristen Saliga, Beth A. Costine, Ann-Christine Duhaime

Departmental Papers (BE)

We have developed the first immature large animal translational treatment trial of a pharmacologic intervention for traumatic brain injury (TBI) in children. The preclinical trial design includes multiple doses of the intervention in two different injury types (focal and diffuse) to bracket the range seen in clinical injury and uses two post-TBI delays to drug administration. Cyclosporin A (CsA) was used as a case study in our first implementation of the platform because of its success in multiple preclinical adult rodent TBI models and its current use in children for other indications. Tier 1 of the therapy development platform assessed ...


Noninvasive Metrics For Identification Of Brain Injury Deficits In Piglets, Samer A. Jaber, Sarah Sullivan, Susan S. Margulies Feb 2015

Noninvasive Metrics For Identification Of Brain Injury Deficits In Piglets, Samer A. Jaber, Sarah Sullivan, Susan S. Margulies

Departmental Papers (BE)

Balance and bispectral index metrics were evaluated in piglets following focal and diffuse brain injury. A significant decrease in bispectral index existed at 24 hours after diffuse brain injury, but not after focal injury. Postural sway increased at 1–6 hours after both focal and diffuse injuries.


The Anesthetic Effects On Vasopressor Modulation Of Cerebral Blood Flow In An Immature Swine Model, Benjamin Bruins, Todd Kilbaugh, Susan S. Margulies, Stuart H. Friess Apr 2013

The Anesthetic Effects On Vasopressor Modulation Of Cerebral Blood Flow In An Immature Swine Model, Benjamin Bruins, Todd Kilbaugh, Susan S. Margulies, Stuart H. Friess

Departmental Papers (BE)

BACKGROUND: The effect of various sedatives and anesthetics on vasopressor modulation of cerebral blood flow (CBF) in children is unclear. In adults, isoflurane has been described to decrease CBF to a lesser extent than fentanyl and midazolam. Most large-animal models of neurocritical care use inhaled anesthetics for anesthesia. Investigations involving modulations of CBF would have improved translatability within a model that more closely approximates the current practice in the pediatric intensive care unit.

METHODS: Fifteen 4-week-old piglets were given 1 of 2 anesthetic protocols: total IV anesthesia (TIVA) (midazolam 1 mg/kg/h and fentanyl 100 μg/kg/h, n ...


Uses Of Remnant Human Lung Tissue For Mechanical Stretch Studies, Nurit Davidovich, Peter Chhour, Susan S. Margulies Dec 2012

Uses Of Remnant Human Lung Tissue For Mechanical Stretch Studies, Nurit Davidovich, Peter Chhour, Susan S. Margulies

Departmental Papers (BE)

Human lung tissue donated for research purposes is a precious resource which can enhance the exploration of mechanisms involved in ventilator-induced lung injury (VILI). The goal of this work was to establish methods and demonstrate the feasibility of obtaining viable primary human type I-like alveolar epithelial cells (AECs) from remnant tissue, even after a significant lapse in post-mortem time, as well as human precision-cut lung slices (PCLSs), and stretch them at magnitudes correlated with mechanical ventilation volumes. Although after 3 days in culture many of the isolated cells stained for the type II AEC marker pro-surfactant Protein C (pro-SPC), after ...


Scanner-Free And Wide-Field Endoscopic Imaging By Using A Single Multimode Optical Fiber, Youngwoon Choi, Changhyeong Yoon, Moonseok Kim, Taeseok Daniel Yang, Christopher Fang-Yen, Ramchandra R. Dasari, Kyoung Jin Lee, Wonshik Choi Nov 2012

Scanner-Free And Wide-Field Endoscopic Imaging By Using A Single Multimode Optical Fiber, Youngwoon Choi, Changhyeong Yoon, Moonseok Kim, Taeseok Daniel Yang, Christopher Fang-Yen, Ramchandra R. Dasari, Kyoung Jin Lee, Wonshik Choi

Departmental Papers (BE)

A single multimode fiber is considered an ideal optical element for endoscopic imaging due to the possibility of direct image transmission via multiple spatial modes. However, the wave distortion induced by the mode dispersion has been a fundamental limitation. In this Letter, we propose a method for eliminating the effect of mode dispersion and therefore realize wide-field endoscopic imaging by using only a single multimode fiber with no scanner attached to the fiber. Our method will potentially revolutionize endoscopy in various fields encompassing medicine and industry.


Early Cerebral Perfusion Pressure Augmentation With Phenylephrine After Traumatic Brain Injury May Be Neuroprotective In A Pediatric Swine Model, Stuart H. Friess, Colin Smith, Todd Kilbaugh, Suzanne G. Frangos, Jill Ralston, Mark A. Helfaer, Susan S. Margulies Aug 2012

Early Cerebral Perfusion Pressure Augmentation With Phenylephrine After Traumatic Brain Injury May Be Neuroprotective In A Pediatric Swine Model, Stuart H. Friess, Colin Smith, Todd Kilbaugh, Suzanne G. Frangos, Jill Ralston, Mark A. Helfaer, Susan S. Margulies

Departmental Papers (BE)

Objective: Cerebral perfusion pressureage, and current guidelines recommend maintaining cerebral perfusion pressure between 40 mm Hg–60 mm Hg. Although adult traumatic brain injury studies have observed an increased risk of complications associated with targeting a cerebral perfusion pressure >70, we hypothesize that targeting a cerebral perfusion pressure of 70 mm Hg with the use of phenylephrine early after injury in the immature brain will be neuroprotective.

Design: Animals were randomly assigned to injury with a cerebral perfusion pressure of 70 mm Hg or 40 mm Hg. Diffuse traumatic brain injury was produced by a single rapid rotation of the ...


Rho Kinase Signaling Pathways During Stretch In Primary Alveolar Epithelia, Brian Christopher Dipaolo, Susan S. Margulies May 2012

Rho Kinase Signaling Pathways During Stretch In Primary Alveolar Epithelia, Brian Christopher Dipaolo, Susan S. Margulies

Departmental Papers (BE)

Alveolar epithelial cells (AECs) maintain integrity of the blood-gas barrier with actin-anchored intercellular tight junctions. Stretched type I-like AECs undergo magnitude- and frequency-dependent actin cytoskeletal remodeling into perijunctional actin rings. On the basis of published studies in human pulmonary artery endothelial cells (HPAECs), we hypothesize that RhoA activity, Rho kinase (ROCK) activity, and phosphorylation of myosin light chain II (MLC2) increase in stretched type I-like AECs in a manner that is dependent on stretch magnitude, and that RhoA, ROCK, or MLC2 activity inhibition will attenuate stretch-induced actin remodeling and preserve barrier properties. Primary type I-like AEC monolayers were stretched biaxially ...


Influence Of Age And Fall Type On Head Injuries In Infants And Toddlers, Nicole G. Ibrahim, Joanne Wood, Susan S. Margulies, Cindy W. Christian May 2012

Influence Of Age And Fall Type On Head Injuries In Infants And Toddlers, Nicole G. Ibrahim, Joanne Wood, Susan S. Margulies, Cindy W. Christian

Departmental Papers (BE)

Age-based differences in fall type and neuroanatomy in infants and toddlers may affect clinical presentations and injury patterns.

Objective

Our goal is to understand the influence of fall type and age on injuries to help guide clinical evaluation.

Design/Setting/Participants

Retrospectively, 285 children 0–48 months with accidental head injury from a fall and brain imaging between 2000 and 2006 were categorized by age (infan ≤ 1 year and toddler = 1–4 years) and fall type: low (≤3 ft), intermediate (>3 andft), high height falls (≥10 ft) and stair falls.

Outcome Measures

Clinical manifestations were noted and head injuries separated ...


Finite Element Model Predictions Of Intracranial Hemorrhage From Non-Impact, Rapid Head Rotations In The Piglet, Brittany Coats, Stephanie A. Eucker, Sarah Sullivan, Susan S. Margulies May 2012

Finite Element Model Predictions Of Intracranial Hemorrhage From Non-Impact, Rapid Head Rotations In The Piglet, Brittany Coats, Stephanie A. Eucker, Sarah Sullivan, Susan S. Margulies

Departmental Papers (BE)

Clinicians are charged with the significant task of distinguishing between accidental and inflicted head trauma. Oftentimes this distinction is straightforward, but many times probabilities of injuries from accidental scenarios are unknown making the differential diagnosis difficult. For example, it is unknown whether intracranial hemorrhage (IH) can occur at a location other than a focal contact site following a low height fall. To create a foundation for predicting regional IH in infants, we sought to identify the biomechanical response and injury threshold best able to predict IH in 3–5 day old piglets. First, finite element (FE) model simulations of in ...


Premedication With Meloxicam Exacerbates Intracranial Hemorrhage In An Immature Swine Model Of Non-Impact Inertial Head Injury, Stuart H. Friess, Maryam Y. Naim, Todd Kilbaugh, Jill Ralston, Susan S. Margulies Apr 2012

Premedication With Meloxicam Exacerbates Intracranial Hemorrhage In An Immature Swine Model Of Non-Impact Inertial Head Injury, Stuart H. Friess, Maryam Y. Naim, Todd Kilbaugh, Jill Ralston, Susan S. Margulies

Departmental Papers (BE)

Meloxicam is a cyclo-oxgenase-2 preferential non-steroid anti-inflammatory drug with very effective analgesic and anti-inflammatory effects in swine. Previous reports in piglets have demonstrated that meloxicam also inhibits cyclo-oxgenase-1 and reduces production of thromboxane significantly. We use pre-injury analgesia in our immature swine (3–5 day old piglets) model of brain injury using rapid head rotations without impact. In 23 consecutive subjects we found that premedication with meloxicam (N=6) produced a significantly higher mortality rate (5/6 or 83%) than buprenorphine (N =17, 1/17 or 6%, p < 0.02). On gross neuropathologic examination of the meloxicam-treated swine, we observed massive subdural and subarachnoid bleeding which were not present in buprenorphine-premedicated animals. To our knowledge there are no previous reports in swine of increased bleeding or platelet inhibition associated with meloxicam administration and further research is needed to define mechanisms of action in piglets. We caution the use of meloxicam in swine when inhibition of platelet aggregation might adversely affect refinement of experimental research protocols, such as in stroke, trauma, and cardiac arrest models.


Broad-Specificity Mrna–Rrna Complementarity In Efficient Protein Translation, Pamela A. Barendt, Najaf A. Shah, Gregory A. Barendt, Casim A. Sarkar Mar 2012

Broad-Specificity Mrna–Rrna Complementarity In Efficient Protein Translation, Pamela A. Barendt, Najaf A. Shah, Gregory A. Barendt, Casim A. Sarkar

Departmental Papers (BE)

Studies of synthetic, well-defined biomolecular systems can elucidate inherent capabilities that may be difficult to uncover in a native biological context. Here, we used a minimal, reconstituted translation system from Escherichia coli to identify efficient ribosome binding sites (RBSs) in an unbiased, high-throughput manner. We applied ribosome display, a powerful in vitro selection method, to enrich only those mRNA sequences which could direct rapid protein translation. In addition to canonical Shine-Dalgarno (SD) motifs, we unexpectedly recovered highly efficient cytosine-rich (C-rich) sequences that exhibit unmistakable complementarity to the 16S rRNA of the small subunit of the ribosome, indicating that broad specificity ...


Three-Dimensional Differential Interference Contrast Microscopy Using Synthetic Aperture Imaging, Moonseok Kim, Youngwoon Choi, Christopher Fang-Yen, Yongjin Sung, Kwanhyung Kim, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi Feb 2012

Three-Dimensional Differential Interference Contrast Microscopy Using Synthetic Aperture Imaging, Moonseok Kim, Youngwoon Choi, Christopher Fang-Yen, Yongjin Sung, Kwanhyung Kim, Ramachandra R. Dasari, Michael S. Feld, Wonshik Choi

Departmental Papers (BE)

We implement differential interference contrast (DIC) microscopy using high-speed synthetic aperture imaging that expands the passband of coherent imaging by a factor of 2.2. For an aperture synthesized coherent image, we apply for the numerical post-processing and obtain a high-contrast DIC image for arbitrary shearing direction and bias retardation. In addition, we obtain images at different depths without a scanning objective lens by numerically propagating the acquired coherent images. Our method achieves high-resolution and high-contrast 3-D DIC imaging of live biological cells. The proposed method will be useful for monitoring 3-D dynamics of intracellular particles.


Spin-Labeling Magnetic Resonance Imaging Detects Increased Myocardial Blood Flow After Endothelial Cell Transplantation In The Infarcted Heart, Hualei Zhang, Hui Qiao, Rachel S. Frank, Bin Huang, Kathleen J. Propert, Susan S. Margulies, Victor A. Ferrari, Jonathan A. Epstein, Rong Zhou Feb 2012

Spin-Labeling Magnetic Resonance Imaging Detects Increased Myocardial Blood Flow After Endothelial Cell Transplantation In The Infarcted Heart, Hualei Zhang, Hui Qiao, Rachel S. Frank, Bin Huang, Kathleen J. Propert, Susan S. Margulies, Victor A. Ferrari, Jonathan A. Epstein, Rong Zhou

Departmental Papers (BE)

Background

We quantified absolute myocardial blood flow (MBF) using a spin-labeling MRI (SL-MRI) method after transplantation of endothelial cells (ECs) into the infarcted heart. Our aims were to study the temporal changes in MBF in response to EC transplantation and to compare regional MBF with contractile function (wall motion) and microvascular density.

Methods and Result

We first validated the SL-MRI method with the standard microsphere technique in normal rats. We then induced myocardial infarction in athymic rats and injected 5 million ECs (human umbilical vein endothelial cells) suspended in Matrigel or Matrigel alone (vehicle) along the border of the blanched ...


Effects Of Size Polydispersity On The Extinction Spectra Of Colloidal Nanoparticle Aggregates, Alexander E. Ershov, Ivan L. Isaev, Polina N. Semina, Vadim A. Markel, Sergei V. Karpov Jan 2012

Effects Of Size Polydispersity On The Extinction Spectra Of Colloidal Nanoparticle Aggregates, Alexander E. Ershov, Ivan L. Isaev, Polina N. Semina, Vadim A. Markel, Sergei V. Karpov

Departmental Papers (BE)

We investigate the effect of particle polydispersity on the optical extinction spectra of colloidal aggregates of spherical metallic (silver) nanoparticles, taking into account the realistic interparticle gaps caused by layers of stabilizing polymer adsorbed on the metal surface (adlayers). The spectra of computer-generated aggregates are computed using two different methods. The coupled-multipole method is used in the quasistatic approximation and the coupled-dipole method beyond the quasistatics. The latter approach is applicable if the interparticle gaps are sufficiently wide relative to the particle radii. Simulations are performed for two different particle size distribution functions (bimodal and Gaussian), varying the number of ...


Ischemia Induces P-Selectin-Mediated Selective Progenitor Cell Engraftment In The Isolated-Perfused Heart, Jason A. Burdick, Jeremy A. Elser, Brendan P. Purcell, Irshad A. Allana, Kenneth B. Margulies Jan 2012

Ischemia Induces P-Selectin-Mediated Selective Progenitor Cell Engraftment In The Isolated-Perfused Heart, Jason A. Burdick, Jeremy A. Elser, Brendan P. Purcell, Irshad A. Allana, Kenneth B. Margulies

Departmental Papers (BE)

Clinical trials infusing Bone Marrow Cells (BMCs) into injured hearts have produced measureable improvements in cardiac performance, but were insufficient to improve patient outcomes. Low engraftment rates are cited as probable contributor to limited improvements. To understand the mechanisms that control myocardial engraftment of BMCs following ischemia-reperfusion injury, in isolated–perfused mouse hearts, stop-flow ischemia was followed by variable-duration reperfusion (0–60 min) before addition of labeled syngenic BMCs to the perfusate. After a buffer-only wash, the heart was disaggregated. Retained BMCs (digest) and infused BMCs (aliquot) were compared by flow cytometry for c-kit and CD45 expression to determine the ...


Sepsis Enhances Epithelial Permeability With Stretch In An Actin Dependent Manner, Taylor Sitarik Cohen, Brian Christopher Dipaolo, Gladys Gray Lawrence, Susan S. Margulies Jan 2012

Sepsis Enhances Epithelial Permeability With Stretch In An Actin Dependent Manner, Taylor Sitarik Cohen, Brian Christopher Dipaolo, Gladys Gray Lawrence, Susan S. Margulies

Departmental Papers (BE)

Ventilation of septic patients often leads to the development of edema and impaired gas exchange. We hypothesized that septic alveolar epithelial monolayers would experience stretch-induced barrier dysfunction at a lower magnitude of stretch than healthy alveolar epithelial monolayers. Alveolar epithelial cells were isolated from rats 24 hours after cecal ligation and double puncture (2CLP) or sham surgery. Following a 5-day culture period, monolayers were cyclically stretched for 0, 10, or 60 minutes to a magnitude of 12% or 25% change in surface area (ΔSA). Barrier function, MAPk and myosin light chain (MLC) phosphorylation, tight junction (TJ) protein expression and actin ...


Microrna Modulate Alveolar Epithelial Response To Cyclic Stretch, Nadir Yehya, Adi Yerrapureddy, John Tobias, Susan S. Margulies Jan 2012

Microrna Modulate Alveolar Epithelial Response To Cyclic Stretch, Nadir Yehya, Adi Yerrapureddy, John Tobias, Susan S. Margulies

Departmental Papers (BE)

Background

MicroRNAs (miRNAs) are post-transcriptional regulators of gene expression implicated in multiple cellular processes. Cyclic stretch of alveoli is characteristic of mechanical ventilation, and is postulated to be partly responsible for the lung injury and inflammation in ventilator-induced lung injury. We propose that miRNAs may regulate some of the stretch response, and therefore hypothesized that miRNAs would be differentially expressed between cyclically stretched and unstretched rat alveolar epithelial cells (RAECs).

Results

RAECs were isolated and cultured to express type I epithelial characteristics. They were then equibiaxially stretched to 25% change in surface area at 15 cycles/minute for 1 hour ...


Computer-Aided, Multi-Modal, And Compression Diffuse Optical Studies Of Breast Tissue, David R. Busch Jr Dec 2011

Computer-Aided, Multi-Modal, And Compression Diffuse Optical Studies Of Breast Tissue, David R. Busch Jr

Publicly Accessible Penn Dissertations

Diffuse Optical Tomography and Spectroscopy permit measurement of important physiological parameters non-invasively through ~10 cm of tissue. I have applied these techniques in measurements of human breast and breast cancer. My thesis integrates three loosely connected themes in this context: multi-modal breast cancer imaging, automated data analysis of breast cancer images, and microvascular hemodynamics of breast under compression. As per the first theme, I describe construction, testing, and the initial clinical usage of two generations of imaging systems for simultaneous diffuse optical and magnetic resonance imaging. The second project develops a statistical analysis of optical breast data from many spatial ...


Enhancing Meniscus Repair Through Biomaterial Design, Lara Ionescu Silverman Dec 2011

Enhancing Meniscus Repair Through Biomaterial Design, Lara Ionescu Silverman

Publicly Accessible Penn Dissertations

The knee meniscus is prone to damage, which leads to pain and inhibits mobility in the joint long term. Due to the minimal vascularity, low cellularity and large mechanical forces imparted on the meniscus with normal use, endogenous repair is limited. Resection of the damaged region of the tissue (meniscectomy) remains the most common treatment for a torn meniscus, but this procedure results in cartilage degradation and other adverse changes in the knee joint. Given the prevalence of meniscus damage, there is thus a pressing need for novel approaches to meniscus repair. To address this issue, this thesis developed in ...


Optimization And Translation Of Msc-Based Hyaluronic Acid Hydrogels For Cartilage Repair, Isaac E. Erickson Dec 2011

Optimization And Translation Of Msc-Based Hyaluronic Acid Hydrogels For Cartilage Repair, Isaac E. Erickson

Publicly Accessible Penn Dissertations

Traumatic injury and disease disrupt the ability of cartilage to carry joint stresses and, without an innate regenerative response, often lead to degenerative changes towards the premature development of osteoarthritis. Surgical interventions have yet to restore long-term mechanical function. Towards this end, tissue engineering has been explored for the de novo formation of engineered cartilage as a biologic approach to cartilage repair. Research utilizing autologous chondrocytes has been promising, but clinical limitations in their yield have motivated research into the potential of mesenchymal stem cells (MSCs) as an alternative cell source. MSCs are multipotent cells that can differentiate towards a ...


Schwann Cell Proliferation And Macrophage Infiltration Are Evident At Day 14 After Painful Cervical Nerve Root Compression In The Rat, Yu-Wen Chang, Beth A. Winkelstein Dec 2011

Schwann Cell Proliferation And Macrophage Infiltration Are Evident At Day 14 After Painful Cervical Nerve Root Compression In The Rat, Yu-Wen Chang, Beth A. Winkelstein

Departmental Papers (BE)

Although it is known that different types of nerve root insults can produce radicular pain, it is not known whether the neuronal and Schwann cell pathologies in the nerve root vary between inflammation-induced nerve root injury and traumatic compression. This study examined the extent of Wallerian degeneration and associated cellular repair processes in the nerve root in the context of mechanical hyperalgesia resulting from different modes of painful nerve root injury. The C7 dorsal nerve root underwent a transient 10 gram-force compression (10g), inflammation-induced irritation by chromic gut exposure (Cg), or a combination of those stimuli (10g + Cg). Fourteen days ...