Effect of specialized pro-resolving lipid mediators in the regulation of vascular tone and inflammation in human saphenous vein.

Specialized pro-resolving lipid mediators (SPMs), derived from polyunsaturated fatty acids are important mediators in the resolution of inflammation. Recent studies have focused on the effects of SPMs in cardiovascular health and diseases. However, little is known about the effect SPMs on human vascular tone. Therefore, in this study it is aimed to investigate the effect of various SPMs including resolvin D- and E-series, maresin-1 (MaR1) and lipoxin-A4 (LxA4) on the vascular tone of human isolated saphenous vein (SV) preparations under inflammatory conditions. In addition, we aimed to evaluate the effects of SPMs on the release of pro-inflammatory mediators, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-alpha (TNF- α) from human SV. Pretreatment of isolated of human SV with resolvin E1 (RvE1), resolvin D1 (RvD1) and MaR1 (100 nM, 18 h) significantly reduced the contractile responses to thromboxane A2 mimetic, U46619 whereas pretreatment with LxA4 and RvD2 (100 nM, 18 h) had no significant effect on the vascular tone of SV. Moreover, RvE1, RvD1 and MaR1 but not LxA4 and RvD2 (100 nM, 18 h) pretreatment diminished the release of MCP-1 and TNF-α from SV. In conclusion, our findings suggest that pre-treatment with RvE1, RvD1, and MaR1 could have potential benefits in decreasing graft vasospasm and vascular inflammation in SV.

Mechanism of thromboxane receptor-induced vasoconstriction in human saphenous vein.

Saphenous vein (SV) is one of the most widely used graft material in patients undergoing coronary artery bypass graft surgery (CABG). Thromboxane A2 (TXA2) is implicated in graft failure by inducing vasoconstriction and platelet aggregation. The aim of this study is to investigate the mechanism involved in TXA2-induced vasoconstriction in human SV. The role of different inhibitors and blockers on U46619 (TXA2-mimetic)-induced vasoconstriction is investigated by using an isolated organ bath system. Relaxation responses to several mediators are evaluated in SV pre-contracted with U46619 and compared with those pre-contracted with phenylephrine. Our results demonstrate that U46619-induced contraction is completely blocked by myosin light chain kinase inhibitor ML-9 or TP receptor antagonist BAY u3405. Furthermore, U46619-induced contraction is partially inhibited by phospholipase C inhibitor U73122, protein kinase C inhibitor calphostin C, Rho-kinase inhibitor Y-27632, L-type calcium channel blocker nifedipine, store-operated channel inhibitor SKF96365 or removal of extracellular calcium. Relaxation responses to NO donor (sodium nitroprusside), guanylate cyclase (GC) stimulator (riociguat), phosphodiesterase (PDE) inhibitors (sildenafil, IBMX), adenylate cyclase (AC) activator (forskolin) and acetylcholine (ACh) are markedly reduced when U46619 is used as a pre-contraction agent. Our results demonstrate that influx of extracellular Ca2+ (through L-type calcium channels and store-operated calcium channels) and intracellular Ca2+ release together with Ca2+ sensitization (through Rho-kinase activation) are necessary components for TXA2-induced vasoconstriction in SV. Moreover, more pronounced decrease in vasorelaxation induced by several mediators (SNP, riociguat, sildenafil, IBMX, forskolin, and ACh) in the presence of U46619 when compared with phenylephrine suggests that there is a crosstalk between the TP receptor signaling pathway and PDE, AC, GC enzymes. We believe that the investigation of mechanism of the TXA2-induced vasoconstriction in SV will provide additional information for the prevention of SV graft failure.

The Association Between SYNTAX Score II and Carotid Artery Disease Severity in Patients Who Underwent Coronary Artery Bypass Grafting.

The SYNTAX score (SS) and SS II, which include additional clinical parameters, are widely used today for deciding revascularization following coronary angiography. We investigated the association between the presence and severity of carotid artery disease (CrAD) using the SS and SS II in 287 patients who underwent coronary artery bypass grafting. We based this investigation on the known association between coronary artery disease and CrAD. A significant association was observed between the groups with and without CrAD in terms of SS II values (28.4 ± 9.6 vs 21.4 ± 7.7, respectively; P < .001). A significant difference was also observed when stenosis was classified according to severity as <50%, 50% to 70%, and >70% (P < .001). The results indicated a positive correlation between the presence and severity of CrAD as SS II increased (r = 0.187, P = .005). According to the results of multivariate logistic regression analysis, the SS II was an independent predictor of CrAD.

In Vitro Effects of Eicosapentaenoic and Docosahexaenoic Acid on the Vascular Tone of a Human Saphenous Vein: Influence of Precontractile Agents.

BACKGROUND: Cardiovascular effects of omega-3 polyunsaturated fatty acids including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been widely reported. However, there are limited studies concerning their effects on human blood vessels. Therefore, the aim of this study was to investigate the direct vascular effects of EPA and DHA on the human saphenous vein (SV) precontracted with either prostaglandin F2α (PGF2α), or thromboxane A2 analogue (U46619), or norepinephrine (NE). Moreover, we aimed to investigate the protein expression of free fatty acid receptor 4 (FFAR4) in human SV. METHODS: Pretreatment of human SV rings with EPA and DHA (100 µM, 30 min) was tested on vascular reactivity induced by PGF2α (10 nM to 5 µM), NE (10 nM to 100 µM), and U46619 (1 nM to 100 nM). In addition, direct relaxant effects of EPA/DHA (1-100 µM) were tested in human SV rings precontracted by PGF2α, NE, and U46619. Furthermore, the involvement of potassium channels on their vascular effects was investigated in the presence of the nonselective K+ channel inhibitor tetraethylammonium chloride. RESULTS: Pretreatment with EPA and DHA resulted in a significant decrease in vascular reactivity induced by U46619 and PGF2α compared to NE. In the presence of TEA, the relaxant effects of EPA and DHA were significantly decreased in SV preparations precontracted by U46619 and PGF2α for DHA. Furthermore, FFAR-4 protein was expressed in tissue extracts of human SV. CONCLUSIONS: Our study demonstrates that both EPA and DHA reduce the increased vascular tone elicited by contractile agents on the human SV and that the direct vasorelaxant effect is likely to involve potassium channels.

Primary Cardiac Sarcoma Remission after Surgery: 5-Years Follow-up: Case Report.

BACKGROUND: Primary cardiac sarcoma is a rare and atypical clinical entity. We present a patient with long-term remission after primary cardiac sarcoma resection. CASE REPORT: A 42-year-old previously healthy female presented to the emergency department after an effort-induced 30-minute episode of chest pain and extreme shortness of breath. Physical examination upon admission was remarkable for a pulse of 99/minute; blood pressure was 101/73 mmHg. Transthoracic echocardiography showed a mass measuring 5.5 × 5.6 cm extending from the left septum to the mitral valve anterior leaflet. A multilobulated broad-based 5.5 × 5.6 × 4 cm3 mass invading a large portion of the left septum to the mitral valve anterior leaflet was completely excised in the open heart surgery. Chemotherapy regimen (paclitaxel 175 mg/m2/day on day 1, every 21 days) was started after operation. Full remission was provided. Metastasis and recurrence have not been observed for 5 years of follow-up by PET. We observed during 5 years and used a PET. And the finally we did not see metastasis at the 5 years of follow-up. CONCLUSIONS: We strongly recommend that a patient-specific multidisciplinary approach involving radical resection, chemotherapy, and radiation therapy in these cases results in patient survival and a significant improvement in quality of life. We also think that it is necessary to perform MRI to exclude other illnesses that are considered to be a myxoma.

Omega-3 polyunsaturated fatty acids reduce vascular tone and inflammation in human saphenous vein.

Dietary intake of omega-3 polyunsaturated fatty acids, including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), has been reported to have beneficial cardiovascular effects. However, little is known about the effect of EPA and DHA on human vascular tone. Therefore, the aim of this study is to evaluate the effect of EPA and DHA on vascular tone of the human saphenous vein (SV) obtained from patients undergoing coronary bypass operation under normal and inflammatory conditions. Moreover, we aimed to investigate the effect of EPA and DHA on the release of inflammatory mediators from SV. Pretreatment of SV with EPA and DHA (100µM, 18h) decreased the contractile response of SV to norepinephrine (NE) under normal and inflammatory conditions. Moreover, EPA and DHA pretreatment diminished increased Monocyte Chemoattractant Protein-1 (MCP-1) and Tumor Necrosis Factor-alpha (TNF-α) release from SV under inflammatory conditions. In conclusion, our results suggest that EPA and DHA pretreatment may be beneficial to counteract graft vasospasm and vascular inflammation in SV which are important factors in graft failure development. Therefore, dietary intake of EPA and DHA may have potential clinical applications in improving coronary bypass graft patency.

Inhibition of microsomal PGE synthase-1 reduces human vascular tone by increasing PGI2 : a safer alternative to COX-2 inhibition.

BACKGROUND AND PURPOSE: The side effects of cyclooxygenase-2 (COX-2) inhibitors on the cardiovascular system could be associated with reduced prostaglandin (PG)I2 synthesis. Microsomal PGE synthase-1 (mPGES-1) catalyses the formation of PGE2 from COX-derived PGH2 . This enzyme is induced under inflammatory conditions and constitutes an attractive target for novel anti-inflammatory drugs. However, it is not known whether mPGES-1 inhibitors could be devoid of cardiovascular side effects. The aim of this study was to compare, in vitro, the effects of mPGES-1 and COX-2 inhibitors on vascular tone in human blood vessels. EXPERIMENTAL APPROACH: The vascular tone and prostanoid release from internal mammary artery (IMA) and saphenous vein (SV) incubated for 30 min with inhibitors of mPGES-1 or COX-2 were investigated under normal and inflammatory conditions. KEY RESULTS: In inflammatory conditions, mPGES-1 and COX-2 proteins were more expressed, and increased levels of PGE2 and PGI2 were released. COX-2 and NOS inhibitors increased noradrenaline induced vascular contractions in IMA under inflammatory conditions while no effect was observed in SV. Interestingly, the mPGES-1 inhibitor significantly reduced (30-40%) noradrenaline-induced contractions in both vessels. This effect was reversed by an IP (PGI2 receptor) antagonist but not modified by NOS inhibition. Moreover, PGI2 release was increased with the mPGES-1 inhibitor and decreased with the COX-2 inhibitor, while both inhibitors reduced PGE2 release. CONCLUSIONS AND IMPLICATIONS: In contrast to COX-2 inhibition, inhibition of mPGES-1 reduced vasoconstriction by increasing PGI2 synthesis. Targeting mPGES-1 could provide a lower risk of cardiovascular side effects, compared with those of the COX-2 inhibitors. LINKED ARTICLES: This article is part of a themed section on Targeting Inflammation to Reduce Cardiovascular Disease Risk. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.22/issuetoc and http://onlinelibrary.wiley.com/doi/10.1111/bcp.v82.4/issuetoc.

Control of human vascular tone by prostanoids derived from perivascular adipose tissue.

Perivascular adipose tissue (PVAT) surrounds most vessels and has now been recognized as a regulator of vascular functions. This effect of PVAT has been mostly demonstrated in vessels obtained from rats and mice. Thus, the aim of this study was to investigate anti-contractile effect of PVAT surrounding human coronary bypass grafts such as saphenous vein (SV) and internal mammary artery (IMA). Moreover, we aimed to determine the involvement of prostanoids in the anticontractile effect of PVAT. Human SV and IMA preparations were set up in an organ bath. The presence of PVAT in SV and IMA preparations significantly attenuated the contractile response to noradrenaline (NA). Preincubation with indomethacin, a cyclooxygenase inhibitor, increased NA contraction in SV preparations with PVAT. This effect was not observed in IMA preparation with PVAT incubated with indomethacin. The lower measurements of prostaglandin E2 (PGE2) released from PVAT surrounding IMA versus SV supported these effects. In conclusion, our results show that PVAT of SV could attenuate NA-induced contraction by releasing both PGE2 and prostacyclin (PGI2). In contrast to SV, PVAT of IMA exerts its anti-contractile effect independently from prostanoids. These observations suggest that retaining PVAT in human SV and IMA preparations may have potential clinical implications to improve coronary bypass graft patency.

Simple and new technique to assess left internal mammary artery function by left ventriculography : LIMA imaging with ventriculography.

The aim of this study was to demonstrate an assessment of left internal mammary artery (LIMA) patency and anatomy by standard left ventriculography, and to define a proposal for predicting LIMA function according to left ventriculography outcome. A total of 335 patients with an indication of coronary angiography were included. Standard coronary angiography and left ventriculography were performed initially. Visualization of LIMA occurred in the late phase of ventriculography and the LIMA visualization frame rate was counted for each patient. Then selective LIMA angiography was performed and LIMA diameter, LIMA course and anatomy, and subclavian artery anatomy were noted. Finally, the results of left ventriculography and LIMA angiography were compared by statistical analysis. During left ventriculography, LIMA was visualized in 96.4% of the patients. The mean LIMA visualization frame rate was 53.8 ± 17.7 and the mean LIMA diameter was 2.60 ± 0.36 mm. There was a strong correlation between LIMA visualization frame rate and LIMA diameter, LIMA course, and also asymptomatic subclavian artery disease (P < 0.001). Regression analysis showed that LIMA visualization frame rate is the major independent determinant for LIMA diameter prediction (P < 0.001); LIMA diameter, LIMA course, proximal LIMA side branch, and subclavian artery disease are the major predictors of LIMA visualization on left ventriculography (P < 0.001). LIMA patency and anatomy can be evaluated accurately with a simple method using left ventriculography. Besides direct visualization of LIMA, the visualization frame rate may constitute a reliable parameter for assessing LIMA function. A LIMA visualization frame rate of less than 50 is associated with a healthy and well-sized LIMA.

Interrupted aortic arch or extreme coarctation? A case report and review of the literature.

The hallmark feature of aortic interruption that is useful in differentiating it from aortic coarctation is the "complete absence" of continuity between both parts of the interrupted segment. In this study, we reviewed the 28 patients diagnosed with isolated interrupted aortic arch (IAA) who reached adult age (> 20 years), aimed to review the validity of the Celoria-Patton classification in the literature, and reported the first microscopic pathology of the IAA in an adult.

Treatment strategies for coronary lesions in Takayasu arteritis patients - case report and review of the literature.

Takayasu arteritis is type of vasculitis that usually affects the aorta and its major branches. While coronary involvement is seen infrequently, treatment strategy is less clear. Here, we report a case of a 45 year-old woman with Takayasu arteritis who underwent a Y-graft coronary bypass surgery four years previously. We present the long-term follow-up this patient, with a literature review. and we discuss treatment strategies.

Left atrial thrombus following bilobectomy: a case report.

INTRODUCTION: Left atrial free floating ball thrombus is a relatively rare event, especially without mitral valve disease. CASE PRESENTATION: A 61-year-old Turkish man was admitted to our hospital with a thrombus mass in his left atrium. Five months earlier, he had undergone right bilobectomy and superior bronchoplasty due to squamous cell carcinoma in the lung. The patient had no evidence of cardiac disease except atrial fibrillation and there were no defined embolizations. The thrombus mass was surgically removed. The patient was discharged from hospital on the sixth postoperative day. CONCLUSION: Surgery with cardiopulmonary bypass is a safe method for treatment. The patient should be medicated with warfarin, especially in the presence of atrial fibrillation.

The impact of coronary artery bypass grafting surgical technique on stroke in young and elderly patients.

BACKGROUND: Today, the elderly represent a large and rapidly growing segment of society and are being referred in increasing numbers for coronary artery bypass grafting (CABG) surgery. Stroke is a major complication of CABG surgery. The risk of stroke after CABG can be managed successfully, especially in high-risk patients, by choosing an adequate and appropriate surgical technique. METHODS: We evaluated 890 consecutive patients who underwent isolated CABG surgery by the same team between June 2006 and July 2008. The patients were divided by age into 2 groups. Group I consisted of 480 patients <65 years of age, and group II comprised 410 patients >65 years of age. Each group was then divided into 4 subgroups according to the surgical technique used: double-clamp technique (DCT), single-clamp technique (SCT), off-pump, and on-pump cross-clamp off. Preoperative risk factors for stroke and all clinical data were collected for the patients. RESULTS: In group I, 192 (40%) of the patients were female, and 288 (60%) were male. In group II, 170 (41.5%) were female, and 240 (58.5%) were male. Five patients in each group experienced stroke, with an incidence of 1.04% in group I (4 men and 1 woman) and 1.21% in group II (3 men and 2 women). The stroke rates of the 2 age groups were not significantly different (P= .802). Three of the 480 patients in group I died, with only 1 (33.3%) of the deaths related to stroke. In group II, however, 2 (50%) of the 4 deaths were related to stroke. The incidences of stroke-associated mortality in the 2 age groups were not significantly different (P=1.0). CONCLUSION: Although off-pump and on-pump cross-clamp off techniques were performed for some of the patients, DCT and SCT were used for the majority of the patients. We detected no statistically significant difference between these 2 groups of patients in the impact of applying DCT and SCT on the stroke rate. We conclude that this result was due to the different surgical techniques performed on a minority of the patients (82 patients).

Does the level of soluble intercellular adhesion molecule 1 predict myocardial injury before cardiac markers increase?

BACKGROUND: The measurement of cardiac markers is still the gold standard for diagnosing myocardial infarction (MI), but there is always a transition period between the time of infarction and when a marker can be measured in the blood. Therefore, clinicians are shifting their focus to the identification of potential new analytes capable of predicting MIs before the standard cardiac markers increase. In this study, we tested whether measurement of the concentration of soluble intercellular adhesion molecule 1 (sICAM-1) in plasma can be used for this purpose. MATERIALS AND METHODS: In this prospective study, we included 60 male patients who had a left main coronary artery lesion or a left main equivalent and who underwent elective (group I, n = 20), urgent (group II, n = 20), or emergent (group III, n = 20) coronary artery bypass grafting (CABG). We excluded patients who had increased cardiac markers at admission, and drew blood samples for sICAM-1 measurements from other patients immediately after coronary angiography evaluations. We divided the patients into 3 groups according to their clinical characteristics and cardiac marker levels. Only patients with increased cardiac markers underwent emergent CABG (group III). We measured sICAM-1 concentrations immediately after coronary angiography and measured creatine kinase MB (CK-MB) and cardiac troponin I (cTnI) just before CABG. We then evaluated the results for correlations. RESULTS: CK-MB, cTnI, and sICAM-1 levels were significantly higher in group III than in groups I and II (P < .05 for all). Our analysis for correlations between the sICAM-1 level and cardiac marker levels revealed no significant correlations in group I (CK-MB, r = 0.241 [P = .15]; cTnI, r = -0.107 [P = .32]) and group II (CK-MB, r = -0.202 [P = .19]; cTnI, r = 0.606 [P = .002]), but our analysis did reveal highly significant correlations in group III (CK-MB, r = 0.584 [P = .003]; cTnI, r = 0.605 [P = .002]). CONCLUSION: Measuring the plasma concentration of sICAM-1 before the concentrations of cardiac markers increase in patients with MI may provide clinicians with faster and reliable data for deciding on and administering the most appropriate procedures and/or therapies.

The severity of positional mitral regurgitation during off-pump coronary artery bypass grafting.

BACKGROUND: The aims of this study were to elucidate the incidence of mitral regurgitation during off-pump coronary artery bypass (OPCAB) surgery to evaluate the relationship of the changes with ventricular function and possible mitral valve regurgitation caused by positioning. METHODS: Included in the study were 60 consecutive patients who underwent CAB grafting on the beating heart. We monitored several hemodynamic variables (systolic arterial pressure, mean arterial pressure, right atrial pressure, pulmonary capillary wedge pressure, and heart rate) at baseline and after each anastomosis and used transesophageal echocardiography (TEE) routinely after sternotomy, during each anastomosis, and after completion of the operation. Valvular functions, ejection fraction, and wall motion systolic index were recorded during each TEE evaluation. RESULTS: All of the patients underwent complete revascularization. We performed 132 consecutive OPCAB anastomoses in 60 patients (60 left anterior descending artery [LAD], 20 right coronary artery [RCA], 45 left circumflex coronary artery [LCX], and 7 diagonal artery grafts). During LCX anastomosis, 38 (84.4%) of 45 patients developed moderate mitral regurgitation. The wall motion score index (WMSI) significantly increased during CX grafting, as was demonstrated by higher WMSI values than for the RCA, diagonal, and LAD grafts. The ejection fraction was decreased significantly during CX and RCA anastomoses compared with baseline levels. The hemodynamic changes were in accord with these findings. The greatest hemodynamic compromise was seen during CX anastomosis. CONCLUSION: Positional mitral regurgitation occurs frequently and is a major contributor to hemodynamic instability during posterior- and lateral-wall revascularization during the OPCAB procedure.

The value of admission glycosylated hemoglobin level in patients with acute myocardial infarction.

BACKGROUND: Glycosylated hemoglobin (HbA1c) level on admission is a prognostic factor for mortality in patients with and without diabetes after myocardial infarction. In the present study, the authors examined the relationship between admission HbA1c level and myocardial perfusion abnormalities in patients with acute myocardial infarction. METHODS: One hundred consecutive patients with acute myocardial infarction who were treated with thrombolytic therapy were included in the present prospective study. Blood glucose and HbA1c levels of all patients were measured within 3 h of admission. Patients were divided into three groups according to HbA1c level: 4.5% to 6.4% (n=25), 6.5% to 8.5% (n=28) and higher than 8.5% (n=47). All patients then underwent exercise thallium-201 imaging and coronary angiography to determine ischemic scores and the number of diseased coronary arteries four weeks after admission. RESULTS: Seven patients died within the four-week follow-up period. There was a significant relationship between admission HbA1c level and mortality (P=0.009). Furthermore, there was a significant relationship between HbA1c level and total ischemic scores in patients with acute myocardial infarction (r=0.482; P=0.001). Ischemic scores increased as HbA1c levels increased in patients with acute myocardial infarction. CONCLUSIONS: The results demonstrated that admission plasma glucose and HbA1c levels are prognostic factors associated with mortality after acute myocardial infarction.

Myocardial injury during off-pump surgery. The effect of intraoperative risk factors.

OBJECTIVE: To achieve better outcomes, the degree of myocardial injury due to off-pump coronary artery bypass surgery (OPCAB) must be reduced. We studied the factors that render patients scheduled for OPCAB vulnerable to myocardial injury, using troponin T (cTnT) as a marker of myocardial injury. METHODS: We prospectively investigated 123 patients being operated by a group of surgeons with off-pump technique between January 2001 and June 2006 in Siyami Ersek Thoracic and Cardiovascular Surgery Center. Myocardial injury occurring during surgery was assessed by post-operative cTnT measurement. Then, the relation between intraoperative factors and postoperative cTnT release were statistically evaluated. RESULTS: Blood samples for cTnT measurement were taken from all patients before operation, immediately after arrival at the intensive care unit, then at 6, 12, and 24 hours after distal revascularization. When regarding the intraoperative risk factors, we found that the heart rate, blood pressure and anastomosis time are the main determinant of myocardial cell injury occurring during OPCAB surgery. CONCLUSION: Although aortic cross-clamp and cardioplegic arrest were not used in off-pump myocardial revascularization, the ischemic myocardial cell destruction was also inevitable in off-pump technique. Therefore, management of heart rate and myocardial contractility was desirable not only for precise anastomosis but also for myocardial protection during OPCAB surgery.

Comparative effects of tolazoline and nitroprusside on human isolated radial artery.

BACKGROUND: The radial artery is increasingly being used in coronary revascularization as an alternative conduit to a saphenous vein graft. Its perfect endothelial capacity provides a high patency rate comparable with the internal mammary artery (IMA). However, its spastic characteristics cause difficulties during its intraoperative preparation and may lead to early postoperative graft failure. Thus, treatment and/or prevention of radial artery spasm with an effective vasodilator agent is essential for its longevity. Endogenous vasoconstrictors, including noradrenaline, endothelin-1, and thromboxane A2, are likely to play a role in the pathogenesis of graft spasm. In the present study, we evaluated the vasorelaxant effect of tolazoline, a nonselective alpha-adrenoceptor blocker, against the contractions induced by various spasmogenic agents in an isolated human radial artery. METHODS: Tolazoline (10(-9)-10(-4) M) or sodium nitroprusside (SNP, 10(-9)-10(-4) M) were cumulatively applied on radial artery rings precontracted submaximally with noradrenaline, endothelin-1, thromboxane analogue, U46619, or potassium chloride. In addition, some rings were pretreated with tolazoline (4 x 10(-6) M) for 30 minutes and the contractile response curve to noradrenaline was assessed in its presence. RESULTS: Tolazoline effectively reversed noradrenaline-induced contractions in the radial artery, whereas it failed to produce remarkable relaxations on rings contracted with other spasmogenic agents, while SNP overcame the contractions induced by all spasmogens to a similar extent. In addition, brief pretreatment of radial artery rings with tolazoline significantly inhibited the contractions to noradrenaline. CONCLUSIONS: Tolazoline is not as broadly effective as SNP against all spasmogens investigated; however, it may be effective in counteracting alpha-adrenoceptor-mediated vasospasm in human radial arteries.

Effects of intermittent fasting on serum lipid levels, coagulation status and plasma homocysteine levels.

BACKGROUND: During Ramadan, Muslims fast during the daylight hours for a month. The duration of restricted food and beverage intake is approximately 12 h/day which makes Ramadan a unique model of intermittent fasting. Many physiological and psychological changes are observed during Ramadan that are probably due to the changes in eating and sleeping patterns. METHODS: Serum total cholesterol, triglycerides, high-density lipoprotein (HDL), low-density lipoprotein (LDL), prothrombin time, activated partial thromboplastin time (aPTT), plasma fibrinogen, D-dimer and homocysteine levels were measured in 24 healthy fasting volunteers (12 females, 12 males) aged 21-35 years. Venous blood samples were taken 1 week before Ramadan, on the 21st day of Ramadan and 20 days after Ramadan. RESULTS: No significant changes were observed on serum total cholesterol, triglycerides and LDL levels. HDL levels were significantly elevated during Ramadan (p < 0.001) and 20 days after Ramadan (p < 0.05). Prothrombin time, aPTT, fibrinogen and D-dimer levels were in the physiologic limits in all samples but D-dimer levels were significantly low at the end of Ramadan in comparison to pre- and post-fasting levels (p < 0.001). Homocysteine levels, being still in reference ranges, were low during Ramadan (p < 0.05) and reached the pre-fasting levels after Ramadan. CONCLUSION: Our results demonstrate that intermittent fasting led to some beneficial changes in serum HDL and plasma homocysteine levels, and the coagulation status. These changes may be due to omitting at least one meal when the body was particularly metabolically active and possibly had a low blood viscosity level at the same time. We conclude that intermittent fasting may have beneficial effects on hemostatic risk markers for cardiovascular diseases.