Pharmacy and Pharmaceutical Sciences Commons^™

Unifying The Mathematical Modeling Of In Vivo And In Vitro Microdialysis, Peter M. Bungay, Rachita K. Sumbria, Ulrich Bickel

Pharmacy Faculty Articles and Research

A unifying approach is presented for developing mathematical models of microdialysis that are applicable to both in vitro and in vivo situations. Previous models for cylindrical probes have been limited by accommodating analyte diffusion through the surrounding medium in the radial direction only, i.e., perpendicular to the probe axis, or by incomplete incorporation of diffusion in the axial direction. Both radial and axial diffusion are included in the present work by employing two-dimensional finite element analysis. As in previous models, the nondimensional clearance modulus (Θ) represents the degree to which analyte clearance from the external medium influences diffusion through the …

Polyethylenimine-Conjugated Gold Nanoparticles: Gene Transfer Potential And Low Toxicity In The Cornea, Ajay Sharma, Ashish Tandon, Jonathan C. K. Tovey, Rangan Gupta, J. David Robertson, Jennifer A. Fortune, Alexander M. Klibanov, John W. Cowden, Frank G. Rieger, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

This study examined the gene transfer efficiency and toxicity of 2-kDa polyethylenimine conjugated to gold nanoparticles (PEI2-GNP) in the human cornea in vitro and rabbit cornea in vivo. PEI2-GNP with nitrogen-to-phosphorus (N/P) ratios of up to 180 exhibited significant transgene delivery in the human cornea without altering the viability or phenotype of these cells. Similarly, PEI2-GNP applied to corneal tissues collected after 12 h, 72 h, or 7 days exhibited appreciable gold uptake throughout the rabbit stroma with gradual clearance of GNP over time. Transmission electron microscopy detected GNP in the keratocytes and the extracellular matrix of the rabbit corneas. …

Significant Inhibition Of Corneal Scarring In Vivo With Tissue-Selective, Targeted Aav5 Decorin Gene Therapy, Rajiv R. Mohan, Ashish Tandon, Ajay Sharma, John W. Cowden, Jonathan C. K. Tovey

Pharmacy Faculty Articles and Research

PURPOSE. This study tested a hypothesis that tissue-selective targeted decorin gene therapy delivered to the stroma with adeno-associated virus serotype 5 (AAV5) inhibits corneal fibrosis in vivo without significant side effects.

METHODS. An in vivo rabbit model of corneal fibrosis was used. Targeted decorin gene therapy was delivered to the rabbit cornea by a single topical application of AAV5 (100 L; 6.5 1012 g/mL) onto the bare stroma for 2 minutes. The levels of corneal fibrosis were determined with stereomicroscopy, slit lamp biomicroscopy, -smooth muscle actin ( SMA), fibronectin, and F-actin immunocytochemistry, and/or immunoblotting. CD11b, F4/80 immunocytochemistry, and TUNEL assay …

Efficacious And Safe Tissue-Selective Controlled Gene Therapy Approaches For The Cornea, Rajiv R. Mohan, Sunilima Sinha, Ashish Tandon, Rangan Gupta, Jonathan C. K. Tovey, Ajay Sharma

Pharmacy Faculty Articles and Research

Untargeted and uncontrolled gene delivery is a major cause of gene therapy failure. This study aimed to define efficient and safe tissue-selective targeted gene therapy approaches for delivering genes into keratocytes of the cornea in vivo using a normal or diseased rabbit model. New Zealand White rabbits, adeno-associated virus serotype 5 (AAV5), and a minimally invasive hair-dryer based vector-delivery technique were used. Fifty microliters of AAV5 titer (6.561012 vg/ml) expressing green fluorescent protein gene (GFP) was topically applied onto normal or diseased (fibrotic or neovascularized) rabbit corneas for 2-minutes with a custom vector-delivery technique. Corneal fibrosis and neovascularization in rabbit …

Targeted Decorin Gene Therapy Delivered With Adeno-Associated Virus Effectively Retards Corneal Neovascularization In Vivo, Rajiv R. Mohan, Jonathan C. K. Tovey, Ajay Sharma, Gregory S. Schultz, John W. Cowden, Ashish Tandon

Pharmacy Faculty Articles and Research

Decorin, small leucine-rich proteoglycan, has been shown to modulate angiogenesis in nonocular tissues. This study tested a hypothesis that tissue-selective targeted decorin gene therapy delivered to the rabbit stroma with adeno-associated virus serotype 5 (AAV5) impedes corneal neovascularization (CNV) in vivo without significant side effects. An established rabbit CNV model was used. Targeted decorin gene therapy in the rabbit stroma was delivered with a single topical AAV5 titer (100 μl; 5x10^12 vg/ml) application onto the stroma for two minutes after removing corneal epithelium. The levels of CNV were examined with stereomicroscopy, H&E staining, lectin, collagen type IV, CD31 immunocytochemistry and …

Gene Delivery In The Equine Cornea: A Novel Therapeutic Strategy, Dylan G. Buss, Ajay Sharma, Elizabeth A. Giuliano, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

Objective—To determine if hybrid adeno-associated virus serotype 2/5 (AAV5) vector can effectively deliver foreign genes into the equine cornea without causing adverse side effects. The aims of this study were to: (i) evaluate efficacy of AAV5 to deliver therapeutic genes into equine corneal fibroblasts (ECFs) using enhanced green fluorescent protein (EGFP) marker gene and (ii) establish the safety of AAV5 vector for equine corneal gene therapy.

Animal Material—Primary ECF cultures were harvested from healthy donor equine corneas. Cultures were maintained at 370C in humidified atmosphere with 5% CO2.

Procedure—AAV5 vector expressing EGFP under control of hybrid cytomegalovirus (CMV) + chicken …

Vector Delivery Technique Affects Gene Transfer In The Cornea In Vivo, Rajiv R. Mohan, Ajay Sharma, Tyler C. Cebulko, Ashish Tandon

Pharmacy Faculty Articles and Research

Purpose: This study tested whether controlled drying of the cornea increases vector absorption in mouse and rabbit corneas in vivo and human cornea ex vivo, and studied the effects of corneal drying on gene transfer, structure and inflammatory reaction in the mouse cornea in vivo.

Methods: Female C57 black mice and New Zealand White rabbits were used for in vivo studies. Donor human corneas were used for ex vivo experiments. A hair dryer was used for drying the corneas after removing corneal epithelium by gentle scraping. The corneas received no, once, twice, thrice, or five times warm air for …

Isolation And Cultivation Of Equine Corneal Keratocytes, Fibroblasts And Myofibroblasts, Dylan G. Buss, Elizabeth A. Giuliano, Ajay Sharma, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

Objective—To establish an in vitro model for the investigation of equine corneal wound healing. To accomplish this goal, a protocol to isolate and culture equine corneal keratocytes, fibroblasts and myofibroblasts was developed.

Animal material—Equine corneal buttons were aseptically harvested from healthy research horses undergoing humane euthanasia for reasons unrelated to this study. Slit-lamp biomicroscopy was performed prior to euthanasia by a board-certified veterinary ophthalmologist to ensure that all samples were harvested from horses free of anterior segment disease.

Procedure—Equine corneal stroma was isolated using mechanical techniques and stromal subsections were then cultured. Customized media at different culture conditions was used …

Impaired M3 And Enhanced M2 Muscarinic Receptor Contractile Function In A Streptozotocin Model Of Mouse Diabetic Urinary Bladder, K. J. Pak, Rennolds S. Ostrom, M. Matsui, F. J. Ehlert

Pharmacy Faculty Articles and Research

We investigated the contractile roles of M2 and M3 muscarinic receptors in urinary bladder from streptozotocin-treated mice. Wild-type and M2 muscarinic receptor knockout (M2 KO) mice were given a single injection of vehicle or streptozotocin (125 mg kg−1) 2–24 weeks prior to bladder assays. The effect of forskolin on contractions elicited to the muscarinic agonist, oxotremorine-M, was measured in isolated urinary bladder (intact or denuded of urothelium). Denuded urinary bladder from vehicle-treated wild-type and M2 KO mice exhibited similar contractile responses to oxotremorine-M, when contraction was normalized relative to that elicited by KCl (50 mM). Eight to 9 weeks after …

Efficacy And Safety Of Mitomycin C As An Agent To Treat Corneal Scarring In Horses Using An In Vitro Model, Dylan G. Buss, Ajay Sharma, Elizabeth A. Giuliano, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

Objective—Mitomycin C (MMC) is used clinically to treat corneal scarring in human patients. We investigated the safety and efficacy of MMC to treat corneal scarring in horses by examining its effects at the early and late stages of disease using an in-vitro model.

Procedure—An in-vitro model of equine corneal fibroblast (ECF) developed was used. The equine corneal fibroblast or myofibroblast cultures were produced by growing primary ECF in the presence or absence of transforming growth factor beta-1 (TGFβ1) under serum-free conditions. The MMC dose for the equine cornea was defined with dose-dependent trypan blue exclusion and MTT [(3-4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assays …

Localization Of Angiotensin Converting Enzyme In Rabbit Cornea And Its Role In Controlling Corneal Angiogenesis In Vivo, Ajay Sharma, Daniel I. Bettis, John W. Cowden, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

Purpose: The renin angiotensin system (RAS) has been shown to modulate vascular endothelial growth factor and angiogenesis. In this study we investigated (i) the existence of the RAS components angiotensin converting enzyme (ACE) and angiotensin II receptors (AT1 and AT2) in the rabbit cornea using in vitro and ex vivo models and (ii) the effect of enalapril, an ACE inhibitor, to inhibit angiogenesis in rabbit cornea in vivo.

Methods: New Zealand White rabbits were used. Cultured corneal fibroblasts and corneal epithelial cells were used for RNA isolation and cDNA preparation using standard molecular biology techniques. PCR was performed to …

Aav Serotype Influences Gene Transfer In Corneal Stroma In Vivo, Ajay Sharma, Jonathan C. K. Tovey, Arkasubhra Ghosh, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

This study evaluated the cellular tropism and relative transduction efficiency of three AAV serotypes, AAV6, AAV8 and AAV9, for corneal gene delivery using mouse cornea in vivo and donor human cornea ex vivo. The AAV6, AAV8 and AAV9 serotypes having AAV2 plasmid encoding for alkaline phosphatase (AP) gene were generated by transfecting HEK293 cell line with pHelper, pARAP4 and pRep/Cap plasmids. Viral vectors (109 vg/μl) were topically applied onto mouse cornea in vivo and human cornea ex vivo after removing the epithelium. Human corneas were processed for transgene delivery at day 5 after viral vector application. Mouse corneas were harvested …

Trichostatin A Inhibits Corneal Haze In Vitro And In Vivo, Ajay Sharma, Maneesh M. Mehan, Sunilima Sinha, John W. Cowden, Rajiv R. Mohan

Pharmacy Faculty Articles and Research

PURPOSE. Trichostatin A (TSA), a histone deacetylase inhibitor, has been shown to suppress TGF- –induced fibrogenesis in many nonocular tissues. The authors evaluated TSA cytotoxicity and its antifibrogenic activity on TGF- –driven fibrosis in the cornea with the use of in vitro and in vivo models.

METHODS. Human corneal fibroblasts (HSFs) were used for in vitro studies, and New Zealand White rabbits were used for in vivo studies. Haze in the rabbit cornea was produced with photorefractive keratectomy (PRK) using excimer laser. Trypan blue exclusion and MTT assays evaluated TSA cytotoxicity to the cornea. Density of haze in the rabbit …

The Guinea Pig Ileum Lacks The Direct, High-Potency, M2-Muscarinic, Contractile Mechanism Of The Mouse Ileum, Michael T. Griffin, Minoru Matsui, Rennolds S. Ostrom, Frederick J. Ehlert

Pharmacy Faculty Articles and Research

We explored whether the M2 muscarinic receptor in the guinea pig ileum elicits a highly potent, direct-contractile response, like that from the M3 muscarinic receptor knockout mouse. First, we characterized the irreversible receptor-blocking activity of 4-DAMP mustard in ileum from muscarinic receptor knockout mice to verify its M3 selectivity. Then, we used 4-DAMP mustard to inactivate M3 responses in the guinea pig ileum to attempt to reveal direct, M2 receptor-mediated contractions. The muscarinic agonist, oxotremorine-M, elicited potent contractions in ileum from wild-type, M2 receptor knockout, and M3 receptor knockout mice characterized by negative log EC50 (pEC50) values ± SEM of …

The C1 And C2 Domains Target Human Type 6 Adenylyl Cyclase To Lipid Rafts And Caveolae, Muthusamy Thangavel, Xiaoqiu Liu, Shu Qiang Sun, Joseph Kaminsky, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Previous data has shown that adenylyl cyclase type 6 (AC6) is expressed principally in lipid rafts or caveolae of cardiac myocytes and other cell types while certain other isoforms of AC are excluded from these microdomains. The mechanism by which AC6 is localized to lipid rafts or caveolae is unknown. In this study, we show AC6 is localized in lipid rafts of COS-7 cells (expressing caveolin-1) and in HEK-293 cells or cardiac fibroblasts isolated from caveolin-1 knock-out mice (both of which lack prototypical caveolins). To determine the region of AC6 that confers raft localization, we independently expressed each of the …

Adenylyl Cyclase Type 6 Overexpression Selectively Enhances Ss-Adrenergic And Prostacyclin Receptor Mediated Inhibition Of Rat Cardiac Fibroblast Function Due To Co-Localization In Lipid Rafts, Xiaoqiu Liu, Muthusamy Thangavel, Shu Qiang Sun, Joseph Kaminsky, Penden Mahautmr, Jeremiah Stitham, John Hwa, Rennolds S. Ostrom

Pharmacy Faculty Articles and Research

Cardiac fibroblasts produce and degrade extracellular matrix and are critical in regulating cardiac remodeling and hypertrophy. Fibroblasts are activated by factors such as transforming growth factor β and inhibited by agents that elevate 3′,5′-cyclic adenosine monophosphate (cAMP) levels. cAMP signal generation and response is known to be compartmentalized in many cell types in part through the colocalization of receptors and specific adenylyl cyclase isoforms in lipid rafts and caveolae. The present study sought to define the localization of key G protein-coupled receptors with adenylyl cyclase type 6 (AC6) in lipid rafts of rat cardiac fibroblasts and to determine if this …

Methods For The Study Of Signaling Molecules In Membrane Lipid Rafts And Caveolae, Rennolds S. Ostrom, Paul A. Insel

Pharmacy Faculty Articles and Research

Lipid rafts and caveolae are cholesterol- and sphingolipid-rich microdomains of the plasma membrane that concentrate components of certain signal transduction pathways. Interest in and exploration of these microdomains has grown in recent years, especially after the discovery of the biochemical marker of caveolae, caveolin, and the recognition that caveolin interacts with many different signaling molecules via its scaffolding domain. There are three major types of caveolins (1, 2, and 3), with some selectivity in their expression in different tissues. Results assessing lipid raft/caveolae co-localization of molecules in signal transduction pathways have provided support for the idea that signaling components are …

Stromal Haze, Myofibroblasts, And Surface Irregularity After Prk, Marcelo V. Netto, Rajiv R. Mohan, Sunilima Sinha, Ajay Sharma, William Dupps, Steven E. Wilson

Pharmacy Faculty Articles and Research

The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze.

Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups[.]

Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr …

Effect Of Prophylactic And Therapeutic Mitomycin C On Corneal Apoptosis, Cellular Proliferation, Haze, And Long-Term Keratocyte Density In Rabbits, Marcelo V. Netto, Rajiv R. Mohan, Sunilima Sinha, Ajay Sharma, Pankaj C. Gupta, Steven E. Wilson

Pharmacy Faculty Articles and Research

PURPOSE—To determine the mechanism through which topical mitomycin C prevents and treats corneal haze after photorefractive keratectomy (PRK) and to examine the effects of dosage and duration of exposure.

METHODS—In 224 New Zealand rabbits, −9.0 diopter PRK with mitomycin C or balanced salt solution was performed. Haze level was graded at the slit-lamp. Rabbits were sacrificed at 4 hours, 24 hours, 4 weeks, or 6 months after surgery and immunohistochemistry was performed with TUNEL assay, Ki67 and α-SMA.

RESULTS—TUNEL-positive apoptotic cells marginally increased in all mitomycin C groups whereas Ki67-positive mitotic cells decreased significantly following mitomycin C application. A greater …

Nitric Oxide Inhibition Of Adenylyl Cyclase Type 6 Activity Is Dependent Upon Lipid Rafts And Caveolin Signaling Complexes, Rennolds S. Ostrom, Richard A. Bundey, Paul A. Insel

Pharmacy Faculty Articles and Research

Several cell types, including cardiac myocytes and vascular endothelial cells, produce nitric oxide (NO) via both constitutive and inducible isoforms of NO synthase. NO attenuates cardiac contractility and contributes to contractile dysfunction in heart failure, although the precise molecular mechanisms for these effects are poorly defined. Adenylyl cyclase (AC) isoforms type 5 and 6, which are preferentially expressed in cardiac myocytes, may be inhibited via a direct nitrosylation by NO. Because endothelial NO synthase (eNOS and NOS3), β-adrenergic ( AR) receptors, and AC6 all can localize in lipid raft/caveolin-rich microdomains, we sought to understand the role of lipid rafts in …

The Evolving Role Of Lipid Rafts And Caveolae In G Protein-Coupled Receptor Signaling: Implications For Molecular Pharmacology, Rennolds S. Ostrom, Paul A. Insel

Pharmacy Faculty Articles and Research

The many components of G-protein-coupled receptor (GPCR) signal transduction provide cells with numerous combinations with which to customize their responses to hormones, neurotransmitters, and pharmacologic agonists. GPCRs function as guanine nucleotide exchange factors for heterotrimeric (α, β, γ) G proteins, thereby promoting exchange of GTP for GDP and, in turn, the activation of ‘downstream’ signaling components. Recent data indicate that individual cells express mRNA for perhaps over 100 different GPCRs (out of a total of nearly a thousand GPCR genes), several different combinations of G-protein subunits, multiple regulators of G-protein signaling proteins (which function as GTPase activating proteins), and various …

Angiotensin Ii Enhances Adenylyl Cyclase Signaling Via Ca2+/Calmodulin. Gq-Gs Cross-Talk Regulates Collagen Production In Cardiac Fibroblasts, Rennolds S. Ostrom, Jennifer E. Naugle, Miki Hase, Caroline Gregorian, James S. Swaney, Paul A. Insel, Laurence L. Brunton, J. Gary Meszaros

Pharmacy Faculty Articles and Research

Cardiac fibroblasts regulate formation of extracellular matrix in the heart, playing key roles in cardiac remodeling and hypertrophy. In this study, we sought to characterize cross-talk between Gq and Gs signaling pathways and its impact on modulating collagen synthesis by cardiac fibroblasts. Angiotensin II (ANG II) activates cell proliferation and collagen synthesis but also potentiates cyclic AMP (cAMP) production stimulated by β-adrenergic receptors (β-AR). The potentiation of β-AR-stimulated cAMP production by ANG II is reduced by phospholipase C inhibition and enhanced by overexpression of Gq. Ionomycin and thapsigargin increased intracellular Ca2+ levels and potentiated isoproterenol- and forskolin-stimulated cAMP production, whereas …

Hypertonic Stress Co-Stimulates T Cell Il-2 Expression Through A Feedback Mechanism Involving Atp Release And P2 Receptor Activation Of P38 Map Kinase, William H. Loomis, Sachiko Namiki, Rennolds S. Ostrom, Paul A. Insel, Wolfgang G. Junger

Pharmacy Faculty Articles and Research

Hypertonic stress (HS) can alter the function of mammalian cells. We have reported that HS enhances differentiated responses of T cells by increasing their ability to produce interleukin (IL)-2, a finding of clinical interest because hypertonic infusions may modulate immune function in patients. HS shrinks cells and mechanically deforms membranes, which results in ATP release from many cell types. Here we investigate if ATP release is an underlying mechanism through which HS augments T cell function. We found that mechanical stress and HS induced rapid ATP release from Jurkat T cells. HS and exogenous ATP mobilized intracellular Ca2+, activated p38 …

Antioxidation Activity Of Dhea And Its Mechanisms, Sun Yang, Han Rui

Pharmacy Faculty Articles and Research

Objective: The aim of this study was to determine the anti-oxidative activity of a new chemopreventive agent--dehydroepiandrosterone (DHEA), and the mechanisms of action by which DHEA protect the thymocytes and DNA from oxidative damage. Methods: Agarose gel electrophoresis, flow cytometry, single cel! gel electrophoresis, chemiluminescence assay, triazolyl blue tetrazolumbromide (MTT) colorimetry, and three dimensional collagen gel assay were used. Results: In agarose gel electrophoresis, 10 nmol/L DHEA blocked the typical DNA degradation (DNA Ladder) induced by H₂O₂. DHEA 2. 5 nmol/L and 10 nmol/L both significantly decreased the percentage of characteristic apoptotic DNA …

Receptor Number And Caveolar Co-Localization Determine Receptor Coupling Efficiency To Adenylyl Cyclase, Rennolds S. Ostrom, Caroline Gregorian, Ryan M. Drenan, Yang Xiang, John W. Regan, Paul A. Insel

Pharmacy Faculty Articles and Research

Recent evidence suggests that many signaling molecules localize in microdomains of the plasma membrane, particularly caveolae. In this study, overexpression of adenylyl cyclase was used as a functional probe of G protein-coupled receptor (GPCR) compartmentation. We found that three endogenous receptors in neonatal rat cardiomyocytes couple with different levels of efficiency to the activation of adenylyl cyclase type 6 (AC6), which localizes to caveolin-rich membrane fractions. Overexpression of AC6 enhanced the maximal cAMP response to β1-adrenergic receptor (β1AR)-selective activation 3.7-fold, to β2AR-selective activation only 1.6-fold and to prostaglandin E2 (PGE2) not at all. Therefore, the rank order of efficacy in …

Role Of KAtp Channels In Reduced Antinociceptive Effect Of Morphine In Streptozotocin-Induced Diabetic Mice, Vivek Sood, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The nociceptive effect was measured using withdrawal latency in tail flick test in mice rendered diabetic by administering streptozotocin (200 mg/kg, i.p.). The antinociceptive effect of morphine (4 and 8 mg/kg, s.c.) and cromakalim, a KATP channel opener, (0.3, 1 and 2 micrograms, i.c.v.) was significantly reduced in diabetic mice. Moreover, co-administration of cromakalim(0.3 microgram) did not alter the reduced antinociceptive effect of morphine(4 mg/kg) in diabetic mice. Spleenectomy in diabetic mice restored the decrease in antinociceptive effect of morphine and cromakalim. Multiple dose treatment with insulin to maintain euglycaemia for 3 days in diabetic mice prevented the decrease in …

Cellular Release Of And Response To Atp As Key Determinants Of The Set-Point Of Signal Transduction Pathways, Rennolds S. Ostrom, Caroline Gregorian, Paul A. Insel

Pharmacy Faculty Articles and Research

The determinants of “basal” activity of signaling pathways regulating cellular responses are poorly defined. One possibility is that cells release factors to establish the set-point of such pathways. Here we show that treatment of Madin-Darby canine kidney cells with the nucleotidase apyrase decreases basal arachidonic acid release and cAMP production 30–40% and that inhibitors of P2Y receptor action also affect basal and forskolin-stimulated cAMP accumulation. Changing medium prominently increases extracellular levels of ATP in Madin-Darby canine kidney, COS-7, and HEK-293 cells. Mechanical stimulation of ATP release likely occurs in virtually every experimental protocol with cultured cells, implicating such release and …

Modulation Of The Pharmacokinetics And Pharmacodynamics Of Proteins By Polyethylene Glycol Conjugation, Reza Mehvar

Pharmacy Faculty Articles and Research

With the rapid advances in the field of biotechnology during the last decade, many peptides and proteins have been produced and evaluated for therapy of various diseases, including cancer. However, rapid clearance and the possibility of immunogenicity after the in vivo administration of these biotechnology-driven products have impeded their marketing. To circumvent these problems, synthetic and natural polymers such as polyethylene glycol (PEG) and dextrans, respectively, have been covalently attached to proteins, and some of these protein-polymer conjugates have shown promising therapeutic results. The conjugation of proteins with polymers usually causes a reduction in the recognition of the protein by …

Effect Of Actinomycin D And Cycloheximide On Ischemic Preconditioning-Induced Delayed Cardioprotective Effect In Rats, Devinder Singh, Ajay Sharma, Manjeet Singh

Pharmacy Faculty Articles and Research

The present study was designed to investigate the effect of actinomycin D, a transcription inhibitor, and cycloheximide, a translation inhibitor, on the delayed cardioprotective effect of ischemic preconditioning. Left thoracotomy was performed in anaesthetized rats at 4th/5th intercostal space and polypropylene suture (5-0) was employed to occlude left common coronary artery. Ischemic preconditioning was produced by four episodes of 5 min of coronary artery occlusion followed by 5 min of reperfusion and thoracic cavity was sutured. Left thoracotomy was performed again after 24 hr of ischemic preconditioning and left coronary artery was occluded for 30 min followed by reperfusion for …

Inhibition Of Cpla2-Mediated Arachidonic Acid Release By Cyclic Amp Defines A Negative Feedback Loop For P2y-Receptor Activation In Mdck-D1 Cells, Mingzhao Xing, Steven Post, Rennolds S. Ostrom, Michael Samardzija, Paul A. Insel

Pharmacy Faculty Articles and Research

In Madin-Darby canine kidney D1cells extracellular nucleotides activate P2Y receptors that couple to several signal transduction pathways, including stimulation of multiple phospholipases and adenylyl cyclase. For one class of P2Y receptors, P2Y2 receptors, this stimulation of adenylyl cyclase and increase in cAMP occurs via the conversion of phospholipase A2 (PLA2)-generated arachidonic acid (AA) to prostaglandins (e.g. PGE2). These prostaglandins then stimulate adenylyl cyclase activity, presumably via activation of prostanoid receptors. In the current study we show that agents that increase cellular cAMP levels (including PGE2, forskolin, and the β-adrenergic agonist isoproterenol) can inhibit P2Y receptor-promoted AA release. The protein kinase …