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47 results on '"Peppas, Athanasios"'

8. Telomere dynamics in macaques and humans

Author

Gardner, Jeffrey P., Kimura, Masayuki, Chai, Weihang, Durrani, Jameel F., Tchakmakjian, Levon, Cao, Xiaojian, Lu, Xiaobin, Li, Guanghui, Peppas, Athanasios P., Skurnick, Joan, Wright, Woodring E., Shay, Jerry W., and Aviv, Abraham

Subjects
Macaques -- Genetic aspects, Macaques -- Comparative analysis, Human beings -- Genetic aspects, Human beings -- Comparative analysis, Man -- Genetic aspects, Man -- Comparative analysis, Telomeres -- Demographic aspects, Aging -- Influence, Aging -- Genetic aspects, Health, Seniors
Abstract

In humans, telomere length in proliferating tissues shortens with age--a process accelerated with age-related diseases. Thus, telomere length and attrition with age in the nonhuman primate may serve as a useful paradigm for understanding telomere biology in humans. We examined telomere parameters in tissues of young and old Macaca fascicularis and compared them with several tissues from humans. Macaque telomeres were variable in length and exhibited partial synchrony (equivalence) within animals. They were longer than humans, partially because of longer subtelomeric segments. As skeletal muscle telomere length was unchanged with age, we used it as an internal reference to offset interanimal variation in telomere length. We identified age-dependent telomere attrition in lung, pancreas, skin, and thyroid. Similar to humans, telomerase activity was detected in spleen, thymus, digestive tract, and gonads. We conclude that factors that modify telomere attrition and aging in humans may also operate in the macaque.

Published
2007

9. Design and construction of three-dimensional physiologically-based vascular branching networks for respiratory assist devices

Author

Santos, Jose A., primary, Gimbel, Alla A., additional, Peppas, Athanasios, additional, Truslow, James G., additional, Lang, Daniel A., additional, Sukavaneshvar, Sivaprasad, additional, Solt, Derek, additional, Mulhern, Thomas J., additional, Markoski, Alex, additional, Kim, Ernest S., additional, Hsiao, James C.-M., additional, Lewis, Diana J., additional, Harjes, Daniel I., additional, DiBiasio, Christopher, additional, Charest, Joseph L., additional, and Borenstein, Jeffrey T., additional

Published
2021
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11. Gender differences on the effects of aging on cardiac and peripheral adrenergic stimulation in old conscious monkeys

Author

Takagi, Gen, Asai, Kuniya, Vatner, Stephen F., Kudej, Raymond K., Rossi, Franco, Peppas, Athanasios, Takagi, Ikuyo, Resuello, Ranillo R.G., Natividad, Filipinas, Shen, You-Tang, and Vatner, Dorothy E.

Subjects
Aging -- Research, Biological sciences
Abstract

We examined the effects of gender and aging on cardiac and peripheral hemodynamic responses to [beta]-adrenergic receptor ([beta]-AR) stimulation in young (male = 5.9 [+ or -] 0.4 yr old and female = 6.5 [+ or -] 0.7 yr old) and old (male = 19.8 [+ or -] 0.7 yr old and female = 21.2 [+ or -] 0.2 yr old) conscious monkeys (Macaca fascicularis), chronically instrumented for measurements of left ventricular (LV) and arterial pressures as well as cardiac output. Baseline LV pressure, the first derivative of LV pressure (LV dP/dt), cardiac index, mean arterial pressure, total peripheral resistance (TPR), and heart rate in conscious monkeys were not different among the four groups. Increases in LV dP/dt in response to 0.1 [micro]g/kg isoproterenol (Iso) were diminished (P < 0.05) in old males (+99 [+ or -] 11%) compared with young males (+194 [+ or -] 18%). In addition, the inotropic responses to norepinephrine (NE) and forskolin (FSK) were significantly depressed (P < 0.05) in old males. Iso-induced reductions of TPR were less (P < 0.05) in old males (-28 [+ or -] 2%) than in young males (-49 [+ or -] 2%). The changes of TPR in response to NE and FSK were also significantly attenuated (P < 0.05) in old males. However, the LV dP/dt responses to BAY y 5959 (15 [micro]g*[kg.sup.-1]* [min.sup.-1]), a [Ca.sup.2+] channel promotor independent of [beta]-AR signaling, were not significantly different between old and young males. In contrast to results in male monkeys, LV dP/dt and TPR responses to Iso, NE, and FSK in old females were similar to those observed in young females. Thus both cardiac contractile and peripheral vascular dynamic responses to [beta]-AR stimulation are preserved in old female but not old male monkeys. This may explain, in part, the reduced cardiovascular risk in the older female population. sympathetic nerves; nonhuman primates; cardiac function; catecholamine desensitization; vascular function; adenosine 3',5'-cyclic monophosphate

Published
2003

12. The effects of chemical treatments on the abrasion resistance of wool fabrics

Author

Peppas, Athanasios and Holme, I.

Subjects
677, Fibres & textiles
Abstract

The low abrasion resistance of wool fabrics compared with many man-made fibre fabrics is known to be a frequent cause of consumer dissatisfaction particularly in pure wool suiting fabrics. Accordingly this project was undertaken to attempt to improve the abrasion resistance in order to maintain the quality image associated with wool fabrics and improve their market competitiveness vis-ä-vis other fabrics. Although several workers have discussed the effects of particular finishes on specific fabrics, very little systematic investigation of the effects of chemical treatments on the abrasion resistance of wool fabrics has been carried out. In the current study the difference in abrasion rates of woven wool fabrics composed of different structures have been studied in relation to the abrasion resistance and other relevant physical properties. The work carried out in this thesis is divided into two parts. A review of the literature is followed by a description of the experimental work carried out. The review of the literature summarises current views on the general mechanisms and factors involved in abrasion processes for textile fabrics and the effects of selective finishing treatments on the abrasion resistance of wool fabrics. In addition details of the abrasion testing conditions used in this work for determining fabric abrasion resistance have been described. The' experimental work is concerned with the changes in wool fabric abrasion resistance produced by the following treatments: (i) Application of polymer shrink-resist finishes by padding and by exhaustion treatments, (ii) Treatment with organic solvents, (iii) Treatment with ethylene glycol at-1500C, (iv) Deamination and esterification, (v) High temperature steaming (130°C), (vi) Dyeing, (vii), Wet abrasion. Because of the great commercial importance of polymer shrink resist finishes for wool fabrics, the main objects of the experimental work were to establish the effects of a range of polymer shrink-resist finishes applied by conventional padding and exhaustion techniques on the abrasion resistance of wool fabrics and the mechanisms by which the abrasion resistance is improved.

Published
1981

20. Early feasibility evaluation of thoracoscopically assisted transcatheter ventricular reconstruction in an experimental model of ischaemic heart failure with left anteroapical aneurysm

Author

Cheng, Yanping, primary, Yi, Geng-Hua, additional, Annest, Lon S., additional, Van Bladel, Kevin, additional, Brown, Ryan, additional, Wechsler, Andrew, additional, Shibuya, Masahiko, additional, Conditt, Gerard B., additional, Peppas, Athanasios, additional, Kaluza, Greg L., additional, and Granada, Juan F., additional

Published
2015
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21. TCT-82 Thoracoscopically Assisted Transcatheter Ventricular Restoration Reverses Left Ventricle Remodeling in the Chronic Anteroseptal Aneurysmal Ovine Model

Author

Cheng, Yanping, primary, Annest, Lon S., additional, Van Bladel, Kevin, additional, Brown, Ryan A., additional, Wechsler, Andrew, additional, Shibuya, Masahiko, additional, Conditt, Gerard B., additional, Peppas, Athanasios, additional, Kaluza, Greg L., additional, Granada, Juan, additional, and Yi, Geng-Hua, additional

Published
2014
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23. A NOVEL ENDOVASCULAR NITINOL IMPLANT PROVIDES A MINIMALLY INJURIOUS STENT ALTERNATIVE FOR CREATING TISSUE APPOSITION: A 90-DAY FEMORAL ARTERY STUDY IN SWINE

Author

Peppas, Athanasios, primary, Giasolli, Robert, additional, Tellez, Armando, additional, Conditt, Gerard, additional, shibuya, masahiko, additional, Burns, Carol, additional, Schneider, Peter, additional, Virmani, Renu, additional, Kolodgie, Frank, additional, Kaluza, Greg, additional, and Granada, Juan, additional

Published
2014
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24. BIOCOMPATIBILITY OF A NOVEL NON-DRUG ELUTING BIOABSORBABLE STENT IN PORCINE CORONARY ARTERIES: AN OPTICAL COHERENCE TOMOGRAPHY AND HISTOLOGY STUDY

Author

Gongora, Carlos A., primary, Tellez, Armando, additional, Ramzipoor, Kamal, additional, Chang, Lee, additional, Cheng, Yanping, additional, Peppas, Athanasios, additional, shibuya, masahiko, additional, narvaez, jose, additional, Rousselle, Serge, additional, Kaluza, Greg, additional, Estrada, Edward A., additional, and Granada, Juan, additional

Published
2014
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25. Experimental evaluation of pharmacokinetic profile and biological effect of a novel paclitaxel microcrystalline balloon coating in the iliofemoral territory of swine

Author

Buszman, Piotr P., primary, Milewski, Krzysztof, additional, Żurakowski, Aleksander, additional, Pajak, Jacek, additional, Jelonek, Michał, additional, Gasior, Paweł, additional, Peppas, Athanasios, additional, Tellez, Armando, additional, Granada, Juan F., additional, and Buszman, Paweł E., additional

Published
2013
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26. TCT-815 Positive Vascular Remodeling and Plaque Vulnerability: Biological Insights from the Novel Familial Hypercholesterolemic Swine Model of Atherosclerosis

Author

Shibuya, Masahiko, primary, Tellez, Armando, additional, Cheng, Yanping, additional, Gongora, Carlos A., additional, Peppas, Athanasios, additional, Purdy, Matthew, additional, Stone, Samantha G., additional, Rate, William, additional, Krueger, Christian, additional, Shanmuganayagam, Dhanansayan, additional, Kaluza, Greg L., additional, and Granada, Juan, additional

Published
2013
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27. TCT-553 A Novel Endovascular Stapling Device Provides a Minimally Injurious Stent Alternative for Maintaining Lumen Patency: A 28-Day Femoral Artery Study in Swine

Author

Peppas, Athanasios, primary, Giasolli, Robert, additional, Tellez, Armando, additional, Burns, Carol A., additional, Conditt, Gerard B., additional, Kolodgie, Frank D., additional, Schneider, Peter A., additional, Shibuya, Masahiko, additional, Virmani, Renu, additional, Kaluza, Greg L., additional, and Granada, Juan, additional

Published
2013
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28. Comparable clinical safety and efficacy of biodegradable versus durable polymer paclitaxel eluting stents despite shorter dual antiplatelet therapy: Insights from a multicenter, propensity score‐matched registry

Author

Buszman, Piotr P., primary, Orlik, Bartlomiej, additional, Trela, Blazej, additional, Milewski, Krzysztof, additional, Kozlowski, Michal, additional, Pruski, Maciej, additional, Drzewiecki, Janusz, additional, Peppas, Athanasios, additional, Granada, Juan F., additional, Kaluza, Greg L., additional, and Buszman, Pawel E., additional

Published
2012
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31. Increases in Vascular Smooth Muscle Stiffness with Aging

Author

Qiu, Hongyu, primary, Zhu, Yi, additional, Gansner, Meredith, additional, Depre, Christophe, additional, Peppas, Athanasios, additional, Resuello, Ranillo, additional, Natividad, Filipinas, additional, Hunter, William, additional, Meininger, Gerald, additional, Genin, Guy, additional, Elson, Elliot, additional, Vatner, Dorothy E., additional, and Vatner, Stephen F., additional

Published
2010
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36. Species Differences in Collagen Expression in Aging Aorta

Author

Qiu, Hongyu, primary, Depre, Christophe, additional, Yang, Guiping, additional, Masurekar, Malthi, additional, Yan, Lin, additional, Ge, Hui, additional, Resuello, Ranilo G., additional, Natividad, Filipinas F., additional, Rossi, Franco, additional, Peppas, Athanasios, additional, Shen, You‐Tang, additional, Vatner, Dorothy E., additional, and Vatner, Stephen F., additional

Published
2007
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40. Sex-specific regulation of gene expression in the aging monkey aorta.

Author

Hongyu Qiu, Bin Tian, Resuello, Ranilo G., Natividad, Filipinas F., Peppas, Athanasios, You-Tang Shen, Vatner, Dorothy E., Vatner, Stephen F., and Depre, Christophe

Abstract

Although increased vascular stiffness is more prominent in aging males than females, and males are more prone to vascular disease with aging, no study has investigated the genes potentially responsible for sex differences in vascular aging. We tested the hypothesis that the transcriptional adaptation to aging differs in males and females using a monkey model, which is not only physiologically and phylogeneti-cally closer to humans than the more commonly studied rodent models but also is not afflicted with the most common forms of vascular disease that accompany the aging process in humans, e.g., atherosclerosis, hypertension, and diabetes. The transcriptional profile of the aorta was compared by high-density microarrays between young and old males or females (n = 6/group). About 600 genes were expressed differentially when comparing old versus young animals. Surprisingly, <5% of these genes were shared between males and females. Radical differences between sexes were especially apparent for genes regulating the extracellular matrix, which relates to stiffness. Aging males were also more prone than females to genes switching smooth muscle cells from the "contractile" to "secretory" phenotype. Other sex differences involved genes participating in DNA repair, stress response, and cell signaling. Therefore, major differences of gene regulation exist between males and females in vascular aging, which may underlie the physiological differences characterizing aging arteries in males and females. Furthermore, the analyses in young monkeys demonstrated differences in genes regulating vascular structure, implying that the sex differences in vascular stiffness that develop with aging are programmed at an early age. [ABSTRACT FROM AUTHOR]

Published
2007
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42. Tissue Uptake, Distribution, and Healing Response After Delivery of Paclitaxel via Second-Generation Iopromide-Based Balloon Coating A Comparison With the First-Generation Technology in the Iliofemoral Porcine Model

Author

Buszman, Piotr P., Tellez, Armando, Afari, Maxwell E., Peppas, Athanasios, Conditt, Gerard B., Rousselle, Serge D., McGregor, Jennifer C., Stenoien, Mark, Kaluza, Greg L., and Granada, Juan F.

Subjects
in-stent restenosis model, second-generation, paclitaxel-coated balloon
Abstract

ObjectivesThis study sought to evaluate vascular drug uptake, distribution and response of second-generation paclitaxel coated balloon (PCB) (Cotavance, MEDRAD Interventional, Indianola, Pennsylvania) and compare it with first-generation technology, containing identical excipient and drug concentration.BackgroundOriginal PCB technologies displayed a heterogeneous deposition of crystalline paclitaxel-iopromide inside the balloon folds, whereas second-generation PCBs consisted of more homogeneous, circumferential coatings.MethodsPaclitaxel tissue uptake was assessed in 20 iliofemoral arteries of a domestic swine. Vascular healing response was assessed in the familial hypercholesterolemic model of iliofemoral in-stent restenosis. Three weeks after bare-metal stent implantation, vascular segments were randomly revascularized with first-generation PCBs (n = 6), second-generation PCBs (n = 6), or plain balloon angioplasty (PBA) (n = 6). At 28 days, angiographic and histological evaluation was performed in all treated segments.ResultsOne-hour paclitaxel tissue uptake was 42% higher in the second-generation PCBs (p = 0.03) and resulted in more homogeneous segment-to-segment distribution compared with first-generation PCBs. Both angiography (percentage of diameter stenosis: second-generation 11.5 ± 11% vs. first-generation 21.9 ± 11% vs. PBA 46.5 ± 10%; p < 0.01) and histology (percentage of area stenosis: second-generation 50.5 ± 7% vs. first-generation 54.8 ± 18% vs. PBA 78.2 ± 9%; p < 0.01) showed a decrease in neointimal proliferation in both PCB groups. Histological variance of the percentage of area stenosis was lower in second-generation compared with first-generation PCBs (51.7 vs. 328.3; p = 0.05). The presence of peristrut fibrin deposits (0.5 vs. 2.4; p < 0.01) and medial smooth muscle cell loss (0 vs. 1.7; p < 0.01) were lower in the second-generation compared with first-generation PCBs.ConclusionsIn the experimental setting, second-generation PCB showed a comparable efficacy profile and more favorable vascular healing response when compared to first-generation PCB. The clinical implications of these findings require further investigation.

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45. Species Differences in Collagen Expression in Aging Aorta.

Author

Hongyu Qiu, Depre, Christophe, Guiping Yang, Masurekar, Malthi, Lin Yan, Hui Ge, Resuello, Ranilo G., Natividad, Filipinas F., Rossi, Franco, Peppas, Athanasios, You-Tang Shen, Vatner, Dorothy E., and Vatner, Stephen F.

Subjects
COLLAGEN, AORTA, PROTEINS, ANIMAL models for aging, WESTERN immunoblotting, LABORATORY rodents, LABORATORY monkeys
Abstract

It is generally thought that an increase in collagen may be responsible for increased vascular stiffness with age. We confirmed this in a rodent model of aging where the protein level of both collagen type 1 and type 3, measured by western blotting, increased by 4-fold in the aorta of old versus young rats (P<0.01). We also analyzed the effects of aging on the thoracic aorta in young (6.6±0.5 yr) vs. old (21.2±0.2 yr) monkeys (Macaca fascicularis). Pressure strain elastic modulus and stiffness index measured in conscious monkeys increased in old male monkeys (P<0.01). Histology showed an increase in medial thickness of the aorta and a maintained collagen density, but elastin density decreased significantly with aging (P<0.05) in male monkeys. Opposite to the rat, there was a significant decrease (P<0.05) in collagen type 1 and 3 in aging monkey aorta. In addition, collagen type 8 (which promotes the neo-intimal proliferation) also increased in the aging monkey aorta. Therefore, changes in collagen isoforms and a decrease in elastin may contribute to vascular stiffening in the aging monkey, mechanisms which appear to be dramatically different from the data in aging rodents. [ABSTRACT FROM AUTHOR]

Published
2007
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47. Obligatory role of cardiac nerves and alpha1-adrenergic receptors for the second window of ischemic preconditioning in conscious pigs.

Author

Kudej RK, Shen YT, Peppas AP, Huang CH, Chen W, Yan L, Vatner DE, and Vatner SF

Subjects
Adrenergic alpha-1 Receptor Antagonists, Adrenergic alpha-Antagonists pharmacology, Animals, Blotting, Western, Cyclooxygenase 2 metabolism, Denervation, In Vitro Techniques, Myocardial Infarction pathology, Myocardial Reperfusion Injury metabolism, Myocardium enzymology, Nitric Oxide Synthase Type II metabolism, Receptors, Adrenergic, alpha-1 metabolism, Swine, Cardiotonic Agents metabolism, Heart innervation, Ischemic Preconditioning, Myocardial classification, Myocardial Reperfusion Injury physiopathology, Nervous System Physiological Phenomena
Abstract

We tested the hypothesis that cardiac nerves may mediate ischemic preconditioning. Pigs were chronically instrumented to measure aortic, left atrial and left ventricular pressures, and regional myocardial function (wall thickening). Hemodynamic variables, area at risk, and tissue blood flows (radioactive microspheres) were similar among groups. Myocardial infarct size following 60 minutes coronary artery occlusion and 4 days reperfusion, expressed as a fraction of the area at risk, was 42+/-4.0%, in innervated pigs and similar in pigs with regional cardiac denervation (CD, 41+/-2.5%). Infarct size in innervated pigs during the first window of preconditioning (first window) was markedly reduced (6+/-1.8%, P<0.01), as it was in the second window of preconditioning (second window) (16+/-3.3%, P<0.01). Although infarct size was still reduced in pigs with CD and first window preconditioning (9+/-1.8%, P<0.01), the protective effects of second window were abrogated in pigs with CD resulting in an infarct size of 38+/-5.6%. In another group of innervated pigs during pharmacological alpha(1)-adrenergic receptor (AR) blockade, infarct size was also not reduced during the second window (48+/-3.2%). Additionally, Western blot analysis of inducible nitric oxide synthase and cyclooxygenase-2 proteins demonstrated significant (P<0.05) upregulation following the second window in innervated pigs, but not in pigs with CD or alpha(1)-AR blockade. Thus, the mechanism of protection during the second window, but not the first window, appears to be dependent on cardiac nerves and alpha(1)-AR stimulation.

Published
2006
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