Yazar "Kerry, Z" seçeneğine göre listele

Listeleniyor 1 - 11 / 11
  • Küçük Resim Yok
    Öğe
    Antioxidant enzyme activities and total nitrite/nitrate levels in the collar model. Effect of nicardipine
    (Walter De Gruyter & Co, 2000) Sozmen, EY; Kerry, Z; Uysal, F; Yetik, G; Yasa, M; Ustunes, L; Onat, T
    There is a large body of literature describing the causative role of oxidative stress mediated by increased levels of reactive oxygen species in the pathogenesis of cardiovascular disease such as atherosclerosis, hypertension, and restenosis after angioplasty. The positioning of a soft silicone collar around the rabbit carotid artery elicits intimal thickening. The findings from recent studies demonstrated that both intimal thickening and atherosclerosis lead to synthesis of inducible nitric oxide synthase, resulting in abundant amounts of nitric oxide. We investigated the effects of collaring and nicardipine treatment on the activities of antioxidant enzymes, superoxide dismutase and catalase, and total nitrite/nitrate levels, stable products of nitric oxide. Placing the collar increased the total nitrite/nitrate levels and decreased superoxide dismutase activity in collared arteries. Treatment with nicardipine (20 mg/kg/day, s.c.) prevented enhanced nitric oxide degradation without affecting superoxide dismutase and catalase activities. Our results suggest that enhanced nitric oxide production and superoxide anion are generated in response to the collaring, resulting in oxidative stress within the segment in this model.
  • Küçük Resim Yok
    Öğe
    Diverse effects of calcium channel blockers in the collar model
    (Acta Cardiologica, 2005) Kerry, Z; Yasa, M; Sevin, G; Reel, B; Anacak, GY; Ozer, A
    Objective - Calcium channel blockers (CCBs) are among the most frequently prescribed cardiovascular drugs. It has been shown that these drugs have antiatherosclerotic effects in both experimental and clinical settings. However, calcium channel blockers have markedly different chemical structures and different effects on the cardiovascular system.We investigated the effect of CD-832, a Ca+2 channel antagonist, on collar-induced intimal thickening, as well as accompanied reactivity changes in rabbit carotid artery. Methods and results - Rabbits received 5 mg/kg/day CD-832 or vehicle (polyethylene glycol, 0.5 ml/kg/day) intramuscularly for a week before and 2 weeks after the collar application. Histological and isometric force measurements were performed in segments from sham and collared carotid arteries. A three-week treatment with CD-832 did not inhibit the intimal thickening caused by perivascular application of a silicone collar. Potassium chloride (KCI), phenylephrine, 5-hydroxytryptamine (5-HT, serotonin) and histamine induced concentration-dependent contractions in both sham-operated (sham) and collared arteries. Collar-induced attenuations in maximum KCI, histamine, phenylephrine and 5-HT contractions were not affected by CD-832. Collaring caused an increase in pD(2) values of 5-HT and a decrease in those of phenylephrine, histamine and acetylcholine. CD-832 did not affect the altered sensitivity to these agonists. Conclusions -These results demonstrate that, in rabbit carotid artery, CD-832 did not inhibit the collar-induced intimal thickening and did not affect the accompanying changes in vascular reactivity.
  • Küçük Resim Yok
    Öğe
    The Effect of a Single Treatment With Cigarette-Smoke on the Blood-Levels and Hemodynamic-Effects of Propranolol In Rats
    (Medecine Et Hygiene, 1989) Berkan, T; Ustunes, L; Kerry, Z; Karol, M; Tosun, M; Yalcinkaya, C; Ozer, A
  • Küçük Resim Yok
    Öğe
    The Effect of Cigarette-Smoke on the Plasma Piroxicam Concentrations In Rats
    (Royal Pharmaceutical Soc Great Britain, 1990) Lermioglu, F; Berkan, T; Yasa, M; Kerry, Z; Yalcinkaya, C; Ozer, A
  • Küçük Resim Yok
    Öğe
    Effect of verapamil on intimal thickening and vascular reactivity in the collared carotid artery of the rabbit
    (Stockton Press, 1996) Ustunes, L; Yasa, M; Kerry, Z; Ozdemir, N; Berkan, T; Erhan, Y; Ozer, A
    1 Intimal thickening is a common site for atherosclerosis. Therefore, we investigated whether the calcium entry blocker verapamil (10 mg kg(-1) body weight day(-1), s.c.) can retard intimal thickening and changes in vascular reactivity induced by a non-occlusive, silicone collar positioned around the left carotid artery of rabbits. The contralateral carotid artery was sham-operated and served as a control. 2 Verapamil and placebo (saline 0.1 ml kg(-1) day(-1), s.c.) treatments were initiated 7 days before placing the collar and lasted 3 weeks. Thereafter, segments were cut from collared and sham-treated arteries for histology and isometric tension recording. 3 The intima/media (I/M) ratio increased after 14 days of collar treatment, but intimal thickening was not inhibited by verapamil (I/M ratio placebo 0.31+/-0.07, verapamil 0.32+/-0.09). 4 The collar decreased the capacity to develop force, as indicated by the response to a supramaximal concentration of KCl, decreased the sensitivity (pD(2)) to acetylcholine (ACh) and phenylephrine (Phe), but increased the sensitivity to 5-hydroxytryptamine (5-HT). 5 Although verapamil did not affect intimal thickening, it normalized the hypersensitivity to 5-HT in collared arteries. 6 The contraction to the supramaximal concentration of KCl was not affected by verapamil. Verapamil decreased the E(max) of ACh, but this was only seen in collar-treated arteries. Verapamil also decreased the sensitivity to ACh and Phe, in both sham- and collar-treated arteries. 7 We conclude that verapamil, without preventing thickening of the intima, can modify collar-induced changes in vascular reactivity.
  • Küçük Resim Yok
    Öğe
    Effects of nicardipine on collar-induced intimal thickening and vascular reactivity in the rabbit
    (Royal Pharmaceutical Soc Great Britain, 1999) Kerry, Z; Yasa, M; Akpinar, R; Sevin, G; Yetik, G; Tosun, M; Ozdemir, N; Erhan, Y; Ustunes, L; Ozer, A
    The effects of nicardipine treatment on collar-induced intimal thickening and on accompanying reactivity changes in rabbit carotid artery have been investigated. Treatment for three weeks with subcutaneous nicardipine (20 mg kg(-1) per day) significantly inhibited the intimal thickening caused by perivascular application of a silicone rubber collar. Potassium chloride (KCl), phenylephrine and 5-hydroxytryptamine (5-HT) induced concentration-dependent contractions in both sham-operated and collared arteries. Collar-induced attenuation of maximum KCl-, phenylephrine- and 5-HT-induced contraction was not affected by nicardipine. Collaring caused the means of pot values (the negative logarithm of EC50 values, 50% effective concentration) of 5-HT and phenylephrine to increase and decrease, respectively. Nicardipine did not affect the altered sensitivity to these agonists. Neither collar implantation nor nicardipine treatment altered the pD(2) values for acetylcholine- and nitroglycerine-induced relaxations. These results demonstrate that nicardipine inhibits collar-induced intimal thickening in rabbit carotid artery without affecting the accompanying changes in vascular reactivity, indicating a possible lack of association between the development of intimal thickening and altered reactivity.
  • Küçük Resim Yok
    Öğe
    The effects of the Harmonic Scalpel on the vasoreactivity and endothelial integrity of the radial artery: A comparison of two different techniques
    (Mosby, Inc, 2001) Cikirikcioglu, M; Yasa, M; Kerry, Z; Posacioglu, H; Boga, M; Yagdi, T; Topcuoglu, N; Buket, S; Hamulu, A
  • Küçük Resim Yok
    Öğe
    Effects of treatment with FK409, a nitric oxide donor, on collar-induced intimal thickening and vascular reactivity
    (Elsevier Science Bv, 1999) Yasa, M; Kerry, Z; Yetik, G; Sevin, G; Reel, B; Ozdemir, N; Erhan, Y; Ustunes, L; Berkan, T; Ozer, A
    Intimal thickening in arteries is considered a site of predilection for atherosclerosis. In a rabbit model of early atherosclerosis, a silastic collar was placed around the carotid artery, which resulted in the formation of intimal thickening. We investigated whether the oral application of FK409 ((+)-(E)-4-ethyl-2-[(E)-hydroxyimino]-5-nitro-3-hexenamide, 10 mg kg(-1) day(-1), p.o.), a nitric oxide donor, inhibited the collar-induced intimal thickening as well as accompanying reactivity changes in rabbit carotid artery. The intimal thickening was significantly inhibited by FK409. The collar treatment increased the pD(2) value of 5-hydroxytryptamine (5-HT) whereas it decreased those of phenylephrine and acetylcholine and did not significantly alter that of nitroglycerine. Maximal contractile force development in response to potassium chloride (KCl), 5-HT and phenylephrine was decreased in collared arteries. The collar did not alter the maximal relaxant effects of acetylcholine and nitroglycerine. Despite the significant reduction of intimal thickening, FK409 treatment did not affect these collar-induced modifications in vascular reactivity. (C) 1999 Elsevier Science B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Effects of vitamin E supplementation on antioxidant status and NO in collar-induced intimal thickening of rabbits.
    (Amer Assoc Clinical Chemistry, 1997) Uysal, F; Sozmen, EY; Dolu, B; Kerry, Z; Ustunes, L; Onat, T; Ozer, A
  • Küçük Resim Yok
    Öğe
    The role of endothelia receptor antagonism in collar-induced intimal thickening and vascular reactivity changes in rabbits
    (Wiley, 2005) Reel, B; Ozkal, S; Islekel, H; Ozer, E; Oktay, G; Sozer, GO; Tanriverdi, S; Turkseven, S; Kerry, Z
    Intimal thickening, due to smooth muscle cell migration and proliferation, is considered to be one of the major components of vascular proliferative disorders such as atherosclerosis and restenosis. One experimental model, resulting in intimal thickening in the rabbit, involves placing a silicon collar around the carotid artery, and is used in this study. Endothelia is known to act as a strong mitogen and to stimulate smooth muscle cell proliferation and migration. We investigated the contribution of endothelia to the development of collar-induced intimal thickening and the effects of TAK-044, (5mg kg(-1) daily, s.c.), a non-selective ETA/ETB receptor antagonist, on intimal thickening and vascular reactivity changes in the collared rabbit carotid artery. Endothelia levels and the intimal cross-sectional area, as well as the ratio of intimal area to media (index), increased significantly in collared arteries as compared with those in sham-operated arteries. TAK-044 significantly inhibited intimal thickening and also decreased the index without affecting increased endothelia levels in collared arteries. Vascular reactivity changes in response to collaring produced predictable effects, such as decreased contractile responses to vasoconstrictor agents and increased sensitivity to serotonin (5-hydroxytryptamine, 5-HT). In terms of contractile responses in this model, TAK-044, in particular, did not affect collar-induced vascular reactivity changes. These results suggest that endothelia may be involved in the pathogenesis of collar-induced intimal thickening. As an endothelia receptor antagonist, TAK-044 may potentially be beneficial in the treatment of atherosclerosis.
  • Küçük Resim Yok
    Öğe
    Telomere length regulation in the proliferation of vascular smooth muscle cells
    (Wiley, 2005) Sozer, GO; Kerry, Z; Oran, I; Gokce, G; McEachern, MJ; Topcu, Z