scholarly journals Physical mechanisms of ultrasonic neurostimulation of the retina

2017 ◽  
Author(s):  
Mike D. Menz ◽  
Patrick Ye ◽  
Kamyar Firouzi ◽  
Kim Butts Pauly ◽  
Butrus T. Khuri-Yakub ◽  
...  
Keyword(s):  
Ganglion Cell ◽  
Physical Mechanism ◽  
Ex Vivo ◽  
Cell Activity ◽  
Standing Waves ◽  
Radiation Force ◽  
Force Model ◽  
Acoustic Frequency ◽  
Frequency Wave

AbstractFocused ultrasound has been shown to be effective at stimulating neurons in vivo, ex vivo and in vitro preparations. Ultrasonic neuromodulation is the only non-invasive method of stimulation that could reach deep in the brain with high spatial-temporal resolution, and thus has potential for use in clinical applications and basic studies of the nervous system. Understanding the physical mechanism by which energy in a high acoustic frequency wave is delivered to stimulate neurons will be important to optimize this technology. Two primary candidates for a physical mechanism are radiation force, the delivery of momentum by the acoustic wave, and cavitation, oscillating gas bubbles. We imaged the isolated salamander retina during ultrasonic stimuli that drive ganglion cell activity and observed micron scale displacements consistent with radiation force. We recorded ganglion cell spiking activity with a planar multielectrode array and changed the acoustic carrier frequency across a broad range (0.5 - 43 MHz), finding that increased stimulation occurs at higher acoustic frequencies, a result that is consistent with radiation force but not cavitation. A quantitative radiation force model can explain retinal responses, and could potentially explain previous in vivo results in the mouse, suggesting a new hypothesis to be tested in vivo. Finally, we found that neural activity was strongly modulated by the distance between the transducer and the electrode array showing the influence of standing waves on the response. We conclude that radiation force is the physical mechanism underlying ultrasonic neurostimulation in the ex vivo retina, and that the control of standing waves is a new potential method to modulate these effects.

TNFR25 Expression on CD4+CD25+ T Cells: Down Modulation of Regulatory Activity.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3165-3165
Author(s):  
Vadim Deyev ◽  
Melinda Roskos ◽  
Robert B. Levy ◽  
Eckhard R. Podack
Keyword(s):  
T Cells ◽  
Cell Function ◽  
Ex Vivo ◽  
Cell Activity ◽  
Treg Cells ◽  
Regulatory Activity ◽  
T Regulatory Cell ◽  
Tnf Receptor Family ◽  
Receptor Family

Abstract TNFR25 (“DR3”) is a member of the TNF receptor family that is expressed by activated CD4+ and CD8+ T cells. To determine if activated CD4+CD25+ T cells also expressed this TNFR family molecule, B6 CD4+CD25+ T cells were stimulated with anti-CD3/CD28 coated beads (kind gift of Dr. B. Blazar, U. Minn.) and expanded for 3–4 days. TNFR25 expression was readily detected on CD4+CD25+ FoxP3+ T cells. Since other members of the TNF receptor family (GITR, OX40, 4–1BB) are known to influence T regulatory cell function, we investigated whether TNFR25 signaling can regulate CD4+CD25+ T cell activity. TNFR25 triggering in B6-wt T regulatory CD4+CD25+ cells with the recombinant TNFR25 ligand TL1A or agonistic anti-TNFR25 antibody (4C12) resulted in reduction of their ability to suppress anti-CD3 induced ex-vivo proliferation of CD4+CD25− cells. 4C12 mediated TNFR25 signaling also reduced B6-wt Treg mediated inhibition of peptide induced proliferation of OVA-specific B6 CD8+ (OT-I) cells. To further investigate a role for TNFR25 in Treg cell regulation, TNFR25 (full length) transgenic mice were generated and bred onto the BL/6 background. CD4+CD25+ cells from these TNFR25 tg mice were found to possess diminished T regulatory activity in vitro as determined by their diminished inability to regulate proliferation by B6-wt CD4+ and OT-I CD8+ T cells. To assess their in vivo regulatory activity, B6-wt and B6 TNFR25 tg Treg cells were examined for their ability to inhibit graft vs. host disease (GVHD) following allogeneic MHC class I/II mismatched BMT. In contrast to B6-wt Treg cells, TNFR25 tg Treg cells exhibited significantly diminished ability to regulate the onset of GVHD in vivo as assessed by weight loss and clinical symptoms. Using agonistic antibody, stimulation of TNFR25 on transgenic Treg cells was also found to effectively remove the ex-vivo regulatory activity expressed by this population. To exclude any possible direct co-stimulatory effects of 4C12 antibody on the responding proliferating cells, CD4+CD25−T cells from TNFR25 dominant negative transgenic mice were employed. 4C12 mab again abolished Treg cell inhibitory activity. The effect of TNFR25 agonists on T reg cell activity in vivo is being further investigated in both mouse models of GVHD and IBD diseases. Initial observations administering 4C12 post-allogeneic BMT together with B6-wt Treg cells indicate a reduction in their ability to regulate GVHD. In total, these studies identify TNFR25 as a new potential target for augmenting CD4+ and CD8+ responses by concomitant direct co-stimulation of effecter cells and inhibition of T regulatory cell function.

Photopheresis in HIV-1 Infected Patients (Pt) Using Benzoporphyrin Derivative (BPD-MA) Induces Apoptosis in CD4 Cells, Increases Cytolytic T-Cell Activity, Intracellular Expression of Chemokines, and Decreases HIV Infectivity and Viral Load.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 1257-1257
Author(s):  
Zale P. Bernstein ◽  
Thomas Dougherty ◽  
Stanley Schwartz ◽  
Sandra Gollnick ◽  
Carleton Stewart ◽  
...  
Keyword(s):  
Viral Load ◽  
Immune System ◽  
T Cell ◽  
Ex Vivo ◽  
Cell Activity ◽  
Area Under The Curve ◽  
Viral Control ◽  
Viral Loads ◽  
Hiv 1

Abstract HIV is able to elude both cellular and humoral arms of the immune system; thereby making viral control difficult. Extra corporeal photochemotherapy (ECP) or photopheresis is an immunomodulatory therapy in which lymphocytes are reinfused into the host after exposure to a photoactive compound and ultraviolet A light. It is an effective therapeutic approach to several disorders of the immune system including acute and chronic graft-versus-host disease, scleroderma, and cutaneous T-cell lymphoma. This process may offer a novel approach to viral control with minimal or no toxicity. We initiated an ex vivo and subsequently a clinical pilot trial utilizing Benzoporphyrin Derivative as the photosensitive compound. Ex vivo dosing studies identified the minimum energy levels of light exposure and concentrations of BPD that eradicated both cell-free and cell-associated HIV-1 infectivity without destroying the virus particles or infected leukocytes. Leukocytes so treated remained viable. They did demonstrate altered cytokine and chemokine expression with apoptosis induced in a minority of CD4 but not CD8 positive cells. Furthermore, there was a statistically significant increase in cytolytic T-cell activity expressed as percentage of granzyme-B release. A pilot in vivo, 24 week clinical trial in seven HIV-1 infected patients (all were required, upon entry, to have viral loads of > 10,000) using the photopheresis parameters established above demonstrated that the treatment was well tolerated and beneficial. Three individuals who had rapidly rising viral loads prior to initiating therapy stabilized once treatment began. Two of which had a (sustained) greater than .5 log decrement and 5 had stable plasma viral loads (less than a .5 log increment or decrement) with varied effects on absolute CD4 and CD8 positive lymphocytes counts. One subject achieved a greater than 1 log decrement in HIV-1 plasma viral load also developed undetectable in vivo cell-free and cell-associated HIV-1 infectivity while demonstrating an increased in vitro lymphocyte mitogen stimulation index. Subsequently, under amended and successor protocol 5 additional 12 month courses were administered to three additional patients and two of the previous enrollees. The area under the curve for viral load (viral load x # of weeks) for these twelve courses of therapy showed a significant decrease from pre to post therapy (p 0.007). There were no significant changes in CD4 or CD8 numbers area under the curve (CD4 number # of weeks and CD8 number x # of weeks). None of the subjects developed an AIDS defining illness during the course of therapy nor were there any treatment associated toxicities. These studies suggest that ECP augments activity of various arms of the immune system without any significant toxicity and may be effective in controlling HIV replication. We now plan a randomized Phase II study utilizing long-term photopheresis (twice monthly for 48 weeks) in addition to anti-retroviral therapy versus anti-retroviral therapy alone to further determine efficacy and mechanism of activity.

Design of an SMA Actuated Mechanotransductive Implant for Correcting Short Bowel Syndrome

2010 ◽  
Author(s):  
Brent Utter ◽  
Brian Barnes ◽  
Jonathan Luntz ◽  
Diann Brei ◽  
Daniel H. Teitelbaum ◽  
...  
Keyword(s):  
Short Bowel Syndrome ◽  
Mechanical Load ◽  
Medical Condition ◽  
Ex Vivo ◽  
The United States ◽  
Tissue Growth ◽  
Force Model ◽  
Short Bowel ◽  
Unique Shape

Short bowel syndrome is a serious medical condition afflicting an estimated 20,000 to 200,000 people in the United States with mortality rates as high as 40%, despite current treatments. Recent research on mechanotransduction, the process through which mechanical load induces tissue growth, has successfully demonstrated permanent growth of healthy, functional bowel in small animals. Unfortunately, the underlying technological approaches limit further research of growth under different load profiles and extension to safe clinical devices. This paper presents a fully implantable bowel extender which expands via a unique Shape Memory Alloy (SMA) driven ratcheting mechanism, measures the bowel tension and load, and enables studies of mechanotransductive bowel tissue growth where the displacement or load may be controlled wirelessly in real-time. The architecture and operation of the bowel extender is illustrated, focusing on the SMA driven ratcheting mechanism that incrementally expands the device. To help visualize the SMA wire and reset spring design, an alternative graphical method is outlined which transforms the SMA material curves into a Reset View based on predictions of the system forces. An analytical model predicts the ratchet mechanism force with tooth and pawl geometry selected based on packaging, load-bearing, and kinematic constraints. Force limits to maintain tissue health are established from ex vivo and in vivo porcine small bowel loading experiments. The Reset View methodology is applied to design a bowel extender prototype which is used to experimentally validate the ratchet force model. The functionality device is demonstrated, operating against loads much larger than specified, validating the device’s ability to enable new studies of mechanotransductive bowel growth in pigs.

scholarly journals DNA-scaffolded biomaterials enable modular and tunable control of cell-based cancer immunotherapies

2019 ◽  
Author(s):  
Xiao Huang ◽  
Jasper Z. Williams ◽  
Ryan Chang ◽  
Zhongbo Li ◽  
Eric Gai ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Cell ◽  
Ex Vivo ◽  
Cell Activity ◽  
Engineered T Cells ◽  
Advanced Biomaterials ◽  
Cancer Immunotherapies ◽  
Biodegradable Particles ◽  
The Impact

Advanced biomaterials provide versatile ways to spatially and temporally control immune cell activity, potentially enhancing their therapeutic potency and safety. Precise cell modulation demands multi-modal display of functional proteins with controlled densities on biomaterials. Here, we develop an artificial immune cell engager (AICE) platform – biodegradable particles onto which multiple proteins are densely loaded with ratiometric control via short nucleic acid tethers. We demonstrate the impact of AICE with varying ratios of anti-CD3 and anti-CD28 antibodies onex vivoexpansion of human primary T cells. We also show that AICE can be used to control the activity of engineered T cellsin vivo. AICE injected intratumorally can provide a local priming signal for systemically administered AND-gate chimeric antigen receptor T cells, driving local tumor clearance while sparing uninjected tumors that model potentially cross-reactive healthy tissues. This modularly functionalized biomaterial thus provides a flexible platform to achieve sophisticated control over cell-based immunotherapies.

Responses to acetylcholine of ganglion cells in an isolated mammalian retina

1976 ◽  
Vol 39 (6) ◽  
pp. 1220-1235 ◽  
Author(s):  
R. H. Masland ◽  
A. Ames
Keyword(s):  
Ganglion Cell ◽  
Action Potentials ◽  
Ganglion Cells ◽  
Cell Activity ◽  
Receptive Fields ◽  
Cholinergic Antagonists ◽  
Control Medium ◽  
High Concentrations ◽  
Evoked Activity

1. Rabbit retinas were isolated and superfused with a physiological medium. Ganglion cell activity was recorded during stimulation with focused light, and receptive fields were mapped. Receptive fields were identical to those found in vivo and did not change during a 6-h incubation. After the receptive field of a ganglion cell had been identified, acetylcholine or related agents were introduced singly or in combination into the medium, and their effect on the cell's spontaneous and light-evoked activity was observed. 2. Ganglion cells with on-center or directionally selective receptive fields were excited when ACh was added to the medium. The response to exogenous ACh was prevented by cholinergic antagonists. 3. These cells' spontaneous activity and response to light were enhanced by anticholinesterase and depressed by cholinergic antagonists. Antagonists varied in their ability to block the light-evoked response, with dihydro-beta-erythroidine the most effective. 4. Thresholds for ACh or the related agents were low, ranging from 1 to 40 muM; their effects were rapidly and completely reversed when the retina was returned to control medium. 5. In retinas incubated in medium containing 20 mM Mg2+ and 0.2 mM Ca2+, ganglion cells lost completely both their spontaneous and light-evoked activity, but retained their ability to generate action potentials in response to elevated K+. Ganglion cell activity rapidly returned to normal when the retina was returned to medium containing normal electrolytes. On-center and directionally selective cells were excited by ACh in retinas where synaptic transmission had been inhibited by 20 mM Mg2+ and 0.2 mM Ca2+. 6. The responses of on-center and directionally selective cells to ACh, to anticholinesterase, and to cholinergic antagonists in control medium indicate that the retina contains one or more synapses using ACh as a neurotransmitter. The response to ACh in retinas exposed to 20 mM Mg2+ and 0.2 mM Ca2+ suggests that at least one such synapse in on the ganglion cell itself. 7. Off-center cells were inhomogenous in their response to ACh. Although some responded just as the other classes of cell, the majority responded quite weakly and a subgroup was encountered which was entirely unaffected by even 1 mM ACh, by levels of physostigmine which inactivate virtually all retinal acetyl-cholinesterase, or by high concentrations of cholinergic antagonists. Only 2 of 20 off-cells tested in the presence of 20 mM Mg2+ and 0.2 mM Ca2+ were excited by ACh. Apparently ACh is not a primary transmitter for most off-cells.

Quality of Leukemia-Derived Dendritic Cells (DC) and T-Cells Are Predictive for the Specific Anti-Leukemic Potential of DC-Trained T-Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4883-4883
Author(s):  
Helga Schmetzer ◽  
Christine Grabrucker ◽  
Anja Liepert ◽  
Andreas Kremser ◽  
Julia Loibl ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Clinical Response ◽  
Memory T Cells ◽  
Ex Vivo ◽  
Cell Activity ◽  
Lytic Activity ◽  
Gm Csf

Abstract The presentation of leukemic antigens can be improved by in vitro conversion of leukemic cells in leukemia-derived DC (DCleu), thereby forming a platform for the generation of leukemia-specific cytotoxic lymphocytes (CTL). DC/ DCleu can be quantified by combination of suitable blast and DC-antigens (Schmetzer 2007). Now we want to enlight the role of the quality of DC/ DCleu and (DC-trained) T-cells to mediate leukemia-cytotoxic reactions ex vivo or to predict or correlate the clinical response to a DC/DLI-based immunotherapy in vivo. Methods: DC were generated with the best of 3 DC-generating methods(‘MCM-mimic’, Lee 2003;’Ca-Ionophore’, Houtenbos 2003; ‘Picibanil’, Sato 2003; Kufner S. 2005 I-III) and used to train T-cells in a ‘Mixed lymphocyte culture’ (MLC) for 10 days in the presence of IL-2 and restimulated with patient-derived DC every 3 days. Co-expression of T-cell-antigens on T-cells was measured before and after MLC. The antileukemic cytotoxic activity of DC-trained (or blast trained or untrained) T-cells against naïve blasts was quantified. We could show, that DC can be generated in every case of AML. In 65% of the cases T-cells gained a leukaemia-lytic activity after 24h training with DC, in 35% an increase of blasts was seen. The T-cell training efficacy with DC was superior to a blast training given rise to specific leukaemia-cytotoxic cells. A comparison of cases with a gain of lytic T-cell activity (n=11)with those without a lytic activity (n=6) showed 78 vs 51% DCleu, 55 vs 34% mature and 32 vs 18% migratory DC and 50vs40% proliferating T-cells, 53 vs 46% memory T-cells, 68vs56% CD4 and 38 vs 60% CD8 pos T-cells. Moreover we could evaluate cut-off values: 90% of DC-trained T-cells could gain a lytic activity if > 65% DCleu were in the MLR. In AML-patients who had presented with a relapse after SCT we could demonstrate a better ex vivo convertibility of blasts to DCleu if patients had successfully responded to a GM-CSF/DLI-based therapy of their relapse after SCT compared to cases with no response (72 vs 36% blasts convertible to DCleu; 44 vs 29% generable DC). Summary: The generation of DC/DCleu is possible in every AML/MDS-patient. Ex vivo convertibility of blasts to DCleu could predict a clinical response to a GM-CSF/DLI-based therapy or indirectly prove, that GM-CSF in vivo could contribute to produce DC/DCleu in vivo. A successful DC-training of T-cells is associated with high matureDC/ DCleu counts and high rates of proliferating, CD4 and Memory-T-cells. The lytic activity of DC-trained T-cells is predictable by quantities of DCleu generable in individual cases. So the generability of DC/DCleu and of DC/MNC-trained T-cells could contribute to predict the clinical course of the disease and could help to create specific anti-leukemic T-cells for immunotherapy of AML.

scholarly journals In Vivo Chemical Screen in Zebrafish Embryos Identifies Regulators of Hematopoiesis Using a Semiautomated Imaging Assay

2016 ◽  
Vol 21 (9) ◽  
pp. 956-964 ◽  
Author(s):  
Guruchandar Arulmozhivarman ◽  
Martin Stöter ◽  
Marc Bickle ◽  
Martin Kräter ◽  
Manja Wobus ◽  
...  
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Ex Vivo ◽  
Human Peripheral Blood ◽  
Screening Method ◽  
Cell Activity ◽  
Cell Types ◽  
Hematopoietic Stem ◽  
Drug Candidates

Hematopoietic stem and progenitor cells (HSPCs) generate all cell types of the blood and are crucial for homeostasis of all blood lineages in vertebrates. Hematopoietic stem cell transplantation (HSCT) is a rapidly evolving technique that offers potential cure for hematologic cancers, such as leukemia or lymphoma. HSCT may be autologous or allogenic. Successful HSCT depends critically on the abundance of engraftment-competent HSPCs, which are currently difficult to obtain in large numbers. Therefore, finding compounds that enhance either the number or the activity of HSPCs could improve prognosis for patients undergoing HSCT and is of great clinical interest. We developed a semiautomated screening method for whole zebrafish larvae using conventional liquid handling equipment and confocal microscopy. Applying this pipeline, we screened 550 compounds in triplicate for proliferation of HSPCs in vivo and identified several modulators of hematopoietic stem cell activity. One identified hit was valproic acid (VPA), which was further validated as a compound that expands and maintains the population of HSPCs isolated from human peripheral blood ex vivo. In summary, our in vivo zebrafish imaging screen identified several potential drug candidates with clinical relevance and could easily be further expanded to screen more compounds.

scholarly journals Radiation Force as a Physical Mechanism for Ultrasonic Neurostimulation of the Ex Vivo Retina

2019 ◽  
Vol 39 (32) ◽  
pp. 6251-6264 ◽  
Author(s):  
Mike D. Menz ◽  
Patrick Ye ◽  
Kamyar Firouzi ◽  
Amin Nikoozadeh ◽  
Kim Butts Pauly ◽  
...  
Keyword(s):  
Physical Mechanism ◽  
Ex Vivo ◽  
Radiation Force

Photopheresis in HIV-1 Infected Patients Utilizing (Benzoporphyrin Derivative Verteporfin/BPD-MA) and Light.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2275-2275
Author(s):  
Zale P. Bernstein ◽  
Thomas Dougherty ◽  
Sandra Gollnick ◽  
Stanley Schwartz ◽  
Supriya Mahajan ◽  
...  
Keyword(s):  
Viral Load ◽  
Ex Vivo ◽  
Stimulation Index ◽  
Energy Levels ◽  
Minimum Energy ◽  
Cell Activity ◽  
Viral Loads ◽  
Hiv 1

Abstract An ex vivo trial utilizing photopheresis with Benzoporphyrin Derivative as the photoactive compound, identified the minimum energy levels of light and concentrations of BPD that eradicated both cell-free and cell-associated HIV-1 infectivity without destroying the virus particles or infected leukocytes. Leukocytes remained viable with altered chemokine/cytokine expression. Apoptosis was induced in a minority of CD4 but not CD8 positive cells with a statistically significant increase in cytolytic T-cell activity. In the 24 week clinical trial in seven HIV-1 infected patients. Three who had rapidly rising viral loads prior to initiating therapy stabilized. Two had a (sustained) greater than .5 log decrement and 5 had stable plasma viral loads (less than a .5 log increment or decrement) with varied effects on absolute CD4 and CD8 positive lymphocytes counts. One achieved a greater than 1 log decrement in HIV-1 plasma viral load and undetectable in vivo cell-free and cell-associated HIV-1 infectivity with an increased in vitro lymphocyte mitogen stimulation index. Under amended protocol 5 additional 12 month courses were administered to three additional patients and two of the previous enrollees. Area under the curve for viral load showed a significant decrease from pre to post therapy (p 0.007). No associated toxicities observed.

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