Combined Therapy of Teicoplanin and Caffeic Acid Phenethyl Ester (CAPE) in the Treatment of Experimental Mediastinitis in the Rat

Post-sternotomy mediastinitis affects 1-3% of patients undergoing cardiac surgery and is lethal in 10-47% of these patients. We investigated the effect of an antioxidant/anti-inflammatory agent, caffeic acid phenethyl ester (CAPE), in the attenuation of inflammatory response induced by methicillin-resistant Staphylococcus aureus (MRSA) infection in a rat experimental mediastinitis model. Rats, divided into six equal groups, received MRSA precolonized stainless steel wire pieces implanted into their mediastinal spaces. Control group and CAPE control group received saline and CAPE 10 micromol/kg.day(-1 )respectively, where Group A received a single dose of teicoplanin 24 mg/kg i.m. for the first day and then 12 mg/kg.day(-1) . Group B received teicoplanin as in Group A plus CAPE 10 micromol/kg. day(-1 )intra-peritoneally. Group C received teicoplanin 60 mg/kg i.m. for the first day and then 30 mg/kg.day(-1 )and Group D received teicoplanin as in Group C plus CAPE 10 micromol/kg.day(-1) . By the end of 14 days rats were sacrificed and serum malondialdehyde (MDA), myeloperoxidase (MPO), nitric oxide (NO), urea and creatinine levels were evaluated. Mediastinal organ tissues were collected for histopathological analysis. Infection rates in all the drug-treated groups were lower than the control groups ( P=0.002) but statistical significance was attained only between the groups A and D ( P=0.018). In connective tissues and the peribronchial area polymorphonuclear leukocytic (PNL) infiltration in the treatment groups, although becoming very close, did not reach statistical significance (P =0.053, P=0.075, respectively). PNL infiltration especially in the peribronchial tissues of the Group B animals was found to be significantly less than the Control and CAPE Control groups with P values of 0.013 and 0.010, respectively. MDA and MPO levels were significantly lower in the treatment groups ( P<0.001 and P<0.001 respectively). Levels of the degradation products of NO were lower in treatment groups compared to two control groups (P=0.003, P= 0.005). NO levels in Group D were lowest among all treatment groups ( P=0.001). It has been demonstrated that although bacterial colonization can be controlled in mediastinitis, the inflammatory response persists. The combination of an antioxidant / anti-inflammatory agent, CAPE, added to standard antibiotic therapy might be effective in the treatment of post-sternotomy mediastinitis due to MRSA.

Citric acid as a decalcifying agent for the excised calcified human heart valves

OBJECTIVE

Cardiac valvular pathologies are frequently encountered as mechanical and functional disorders due to the calcification of the valves whatever the etiologies are. This pathophysiologic table usually ends up with valvular replacement. In this study, we aimed to decrease/eliminate the calcium in the excised calcified human heart valves by using citric acid in vitro hence bringing about the question for possible oral treatment of calcification of the valves by citric acid ingestion.

METHODS

Fourteen pieces of mitral and/or aortic valves excised from 12 patients undergoing valve replacement were placed in a freshly prepared phosphate buffered saline solution containing 0.625% glutaraldehyde at +4 0C for 48 h. They were rinsed with 0.9% NaCl and divided into two groups; study and control. Control tissues were further treated in a freshly prepared solution with identical properties for another 5 days. Study tissues were placed into a solution containing 3.8% citric acid (pH 7.4) and kept for 48 h at +37 degrees C, then rinsed with 0.9% NaCl and transferred into a fresh solution containing 0.625% glutaraldehyde with phosphate buffer at 37 0C for 3 more days. Specimens were biochemically and histopathologically evaluated and compared using Mann Whitney U test.

RESULTS

Calcium and phosphate levels in the study group were lower than in the control group (852.5+/-913.41 microg g-1 vs 413.05+/-519.53 microg g-1, p=0.001 and 207.6+/-321.86 microg g-1 vs 124.4+/-289.48 microg g-1, p=0.035, respectively). Malondialdehyde and protein level values were changed insignificantly in the control and study groups. Histopathologic evaluation showed that collagen and elastin fibers were similar in both groups. In the study group, irregular and fusiform calcific formations around the collagen fibers were significantly decreased.

CONCLUSIONS

Decalcifying human heart valves in vitro conditions with citric acid without an adverse change to the morphology of the valvular tissue specimens is meaningful. We believe that forwarding and looking for the answer to the question "whether systemic application of citric acid could lead to the decalcification and/or reduction of calcification in the native human heart valves" would be expressive.

Prevention of calcification with TPEN in pericardial bioprosthetic heart valve material

OBJECTIVE

Calcification is a frequent cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated bovine pericardium. The major object of the present study is to prevent calcification of pericardial bioprosthetic heart valve materials with TPEN.

METHODS

Bovine pericardium was cut into 2-cm 2 pieces, rinsed in phosphate-buffered saline solution, transferred into +4 degrees C phosphate-buffered saline containing 0.625% glutaraldehyde for initial fixation for 48 h, and allocated into two groups. Control samples were treated in an identical fresh solution for five more days. Others underwent additional fixation in phosphate-buffered saline 2microM TPEN for 48 h. They were then transferred into phosphate-buffered saline + 0.625% glutaraldehyde solution at 37 degrees C (pH 7.4) for three more days. Pericardial patches were inserted into the dorsal pouches of 18 juvenile male Wistar rats as control and study groups. Rats were divided into two groups and sacrificed consecutively by the end of 9th and 12th weeks. The biomechanical properties and calcium contents of explanted tissues were tested and were also assessed histopathologically.

RESULTS

The difference in the calcium contents of the control and study groups' pericardial tissues at the 9th, and 12th weeks were statistically significant (p=0.0001, p=0.0001). The comparison of calcium contents between controls of 9th and 12th weeks and study groups' of the 9th and 12th weeks pericardial tissues were also significant (p=0.0001 and p=0.0001). Histopathologic and biomechanical assessment also supported these findings.

CONCLUSION

Calcific degeneration of glutaraldehyde-fixed bovine pericardium can be reduced by using TPEN without any effect on durability.

Hearing loss in patients undergoing coronary artery bypass grafting with or without extracorporeal circulation

BACKGROUND

Our aim was to investigate the differences in postoperative hearing thresholds in patients undergoing coronary artery bypass grafting with (Group I, n=20) or without (Group II, n=17) extracorporeal circulation.

MATERIAL/METHODS

37 patients undergoing coronary artery bypass grafting with or without extracorporeal circulation were prospectively evaluated in terms of hearing threshold changes with the intention of documenting hearing losses postoperatively. The t-test for two independent variables was used for statistical analysis.

RESULTS

Hearing threshold changes were detected in 9 Group I patients (45%) and 3 Group II patients (17.65%). The difference between the two groups was statistically significant (p=0.0426).

CONCLUSIONS

Postoperative hearing threshold changes, not necessarily revealed by clinical examinations, are encountered after coronary artery bypass grafting operations. Extracorporeal circulation usage seems to bring an additional risk in terms of hearing loss.

Two stage EDTA anti-calcification method for bioprosthetic heart valve materials

BACKGROUND

The aim of this study was to investigate the effect of two-stage EDTA treatment in diminishing calcific degeneration in bovine pericardial bioprosthetic heart valve material.

MATERIAL/METHODS

Conventionally preserved pericardium specimens were divided into two groups. Group I (controls, n=18) pieces were first fixed in phosphate-buffered solution (PBS)+0.6% glutaraldehyde at +4 degrees C for 24 hours, then stored in PBS+0.2% glutaraldehyde at room temperature for 6 days. Group II (study group, n=18) pieces were treated with PBS containing 100 microg/ml ethylenediaminetetraacetic acid (EDTA) at +4 degrees C for 24 hours, then fixed in PBS+0.6% glutaraldehyde as was group I at +4 degrees C for 24 hours. After a second exposure to PBS containing 100 microg/ml EDTA at room temperature for 24 hours, they were stored in PBS+0.2% glutaraldehyde at room temperature for 4 days. Pericardial patches were inserted into the dorsal pouches of 18 juvenile male Wistar rats. After 7 weeks of implantation, all the pericardium pieces were harvested from sacrificed rats. The calcium content and biomechanical properties of the explanted tissues were evaluated and also examined histopathologically.

RESULTS

The difference in the calcium content of the control and study groups was statistically significant. Biomechanical and histopathologic assessment also supported these findings.

CONCLUSIONS

Application of two-stage EDTA was found to be useful in the attenuation of calcification in bioprosthetic heart valve materials with mildly increased durability. As calcification was reduced by approximately 50%, it can be considered for use with other agents as an adjuvant treatment.

Comparison and evaluation of experimental mediastinitis models: precolonized foreign body implants and bacterial suspension inoculation seems promising

Background

Post-sternotomy mediastinitis (PSM) is a devastating surgical complication affecting 1–3% of patients that undergo cardiac surgery. Staphylococcus aureus is one of the most commonly encountered bacterial pathogen cultured from mediastinal samples obtained from patients with PSM. A component of the membrane of the gram positive bacteria, lipoteichoic acid, stimulates the blood monocytes and macrophages to secrete cytokines, radicals and nitrogen species leading to oxido-inflammatory damage. This seems to be responsible for the high mortality rate in PSM. For the evaluation of the pathogenesis of infection or for the investigation of alternative treatment models in infection, no standard model of mediastinitis seems to be available. In this study, we evaluated four mediastinitis models in rats.

Methods

The rats were divided into four groups to form different infection models. Group A: A suspension of 1 × 10⁷ colony-forming units Staphylococcus aureus in 0,5 mL was inoculated from the right second intercostal space into the mediastinum. Group B: A hole was created in the right second intercostal space and a piece of stainless-steel implant with a length of 0.5 cm was inserted into the mediastinum and a suspension of 1 × 10⁷ cfu bacteria in 0,5 mL was administered via the tail vein. Group C: Precolonized stainless-steel implant was inserted into the mediastinum. Group D: Precolonized stainless-steel implant was inserted into the mediastinum and the bacteria suspension was also injected into the mediastinum. On the 10^th day, rats were sacrificed and the extension of infection in the mediastenae was evaluated by quantitative cultures. Myeloperoxidase activity (MPO) and malondialdehyde (MDA) levels were determined in the sera to evaluate the neutrophil activation and assess the inflammatory oxidation.

Results

The degree of infection in group C and D were 83.3% and 100% respectively (P < 0.001). MDA levels were significantly higher in these two groups than the others (P < 0.001).

Conclusion

Infected implants and high bacterial concentration administration were the two important components that played a significant role in the outcome of a successful infection in mediastinum in a rat model.

Iloprost for the attenuation of ischaemia/reperfusion injury in a distant organ

The objective of this study was to investigate antioxidant and cytoprotective properties of iloprost in a distant organ after ischaemia reperfusion injury. Male Wistar rats were divided into two groups. After application of anesthaesia both hindlimbs were occluded. A 2-h reperfusion procedure was carried out after 60 min of ischemia. Study group (STU) rats (n=10) received 10 microg kg(-1) iloprost in 1 ml of saline from the tail vein 10 min before reperfusion. Control (CON) group rats (n=10) received an equal amount of saline. The rats were sacrificed by injection of a high dose of thiopentone sodium. Blood and tissue samples (right kidneys) were taken for analysis. Differences in malondialdehyde (MDA), myeloperoxidase (MPO), Na+-K+ ATPase and total antioxidant capacity (TAC) between the groups were analysed. MPO, MDA and TAC levels in the sera of CON and STU groups were 1.60+/-0.26 U l(-1), 11.42+/-5.23 nmol ml(-1), 8.30 x 10(-2)+/- 3.93 x 10(-2) nmol ml(-1) h(-1) and 1.07+/-0.11 U l(-1), 7.60+/-1.81 nmol ml(-1) and 0.15+/-3.23 x 10(-2) nmol ml(-1) h(-1) (p=0.0001, p=0.043 and p=0.0001 respectively). MPO, ATPase and MDA levels in kidneys for CON and STU groups were 1.24+/-0.58 U g(-1), 85.70+/-52.05 nmol mg(-1), 17.90+/-7.40 nmol ml(-1) and 0.78+/-0.31 U g(-1), 195.90+/-56.13 nmol mg(-1) and 10.10+/-0.99 nmol ml(-1) (p=0.046, p=0.0001 and p=0.009 respectively). When given prior to reperfusion, the positive effect of iloprost in the attenuation of distant organ reperfusion injury has been demonstrated.

Alcohol-induced lung damage and increased oxidative stress

BACKGROUND

Alcohol-induced lung damage may be associated with increased oxidative stress.

OBJECTIVE

Our aim was to investigate alcohol-induced changes in the biochemistry and histopathology of the lung.

METHODS

Rats were divided into two groups, a control group and an ethanol group. The ethanol group received 2 g/kg ethanol (total: 3 ml) intraperitoneally. The controls were given the same amount of saline via the same route. Three hours later, the rats were sacrificed, and blood and lung tissue samples were obtained. Oxidative stress was assessed by measuring the levels of erythrocyte reduced glutathione (GSH), tissue malondialdehyde (MDA), myeloperoxidase (MPO) and Na(+)-K(+) ATPase. Histopathologic evaluation of the lung tissues was also performed.

RESULTS

In the ethanol group, serum and tissue MDA levels and MPO activities were increased (p = 0.007, p = 0.001 and p = 0.000), and lung tissue Na(+)-K(+) ATPase activities and erythrocyte GSH were decreased (p = 0.001 and p = 0.000) compared to the controls. Histopathologic examination demonstrated alveolocapillary thickening, alveolar degeneration, leukocyte infiltration and erythrocyte extravasation in the lungs of the ethanol group (p < 0.05).

CONCLUSION

These results suggest that high-dose acute alcohol administration aggravates systemic and local oxidative stress leading to acute lung injury, ranging from mild pulmonary dysfunction to severe lung injury. It should be borne in mind that rapid onset of the acute respiratory distress syndrome (ARDS) may also be due to increased oxidative stress following alcohol abuse, especially when ischemic disturbances, e.g. coronary heart disease, acute ischemia of the extremities and traumatic accidents, are concomitantly present. Therefore, precautions against ARDS may prevent morbidity and mortality in alcohol-induced lung damage in at-risk patients.

Caffeic acid phenethyl ester (CAPE) supplemented St. Thomas’ hospital cardioplegic solution improves the antioxidant defense system of rat myocardium during ischemia-reperfusion injury

BACKGROUND AND AIM OF STUDY

Cardioplegic arrest remains the method of choice for myocardial protection in cardiac surgery. Caffeic acid phenethyl ester (CAPE) prevents lipid peroxidation induced by ischemia-reperfusion injury and has a potent antioxidant property. We investigated the advantages of CAPE supplemented cardioplegic solution (St. Thomas' Hospital cardioplegic solution No.: 2) on the antioxidant defense system of myocardium against ischemia-reperfusion injury.

MATERIAL AND METHODS

Isolated rat hearts were mounted on a nonrecirculating type of Langendorff apparatus. The hearts were arrested for 60 min with cardioplegic solution given at 20-min intervals and then reperfused for 15 min. The hearts were divided into three groups. Cold saline (0.9%, 4 degrees C) in group 1, St. Thomas' Hospital solution in group 2 and CAPE added St. Thomas' Hospital solution in group 3 were used as the cardioplegic solution. Krebs-Henseleit buffer solution was used for reperfusion. The tissues were examined biochemically for oxidative stress.

RESULTS

Significant differences among the three groups existed in tissue myeloperoxidase (MPO), catalase (CAT), Na+-K+ ATPase activity and in the concentrations of malonydealdehyde (MDA) and 3-nitrotyrosine (3-NT). Group 2 showed significant changes in MPO (P = 0.04), Na+-K+ ATPase enzyme activity (P = 0.02) and the levels of MDA (P = 0.004) and 3-NT (P = 0.01) in comparison with group 1. Group 3 efficiently reduced MDA levels (P = 0.004) and also led to significant decrease in levels of MPO (P = 0.006), 3-NT (P = 0.01) and Na+-K+ ATPase activity (P = 0.01) and increase in the level of CAT (P = 0.004) in comparison with group 1. Significant changes were also found in the levels of MDA (P = 0.03), MPO (P = 0.04) and CAT (P = 0.009) in comparison between groups 2 and 3.

CONCLUSIONS

We demonstrated that the administration of CAPE into cardioplegic solutions improves the antioxidant defense system of rat heart during the ischemia-reperfusion injury.

The effect of ethylenediaminetetraacetic acid on calcific degeneration in bovine pericardium

Calcification is the most frequent cause of the clinical failure of bovine pericardium bioprosthetic valves, preventing their widespread application for surgical treatment. The aim of this study was to minimize calcific degeneration in bovine pericardium by using a chelating agent, ethylenediaminetetraacetic acid (EDTA). Freshly excised bovine pericardium was dissected free from adhering fat tissue and cut into 1-cm(2) pieces that were rinsed in phosphate-buffered saline solution (PBS) and transferred into 4 degrees C PBS containing 1% glutaraldehyde (GA) for initial fixation, then allocated into two groups. Group I received the same treatment in a fresh solution for 5 more days. Group II underwent an additional fixation step in PBS solution (pH 7.4, 37 degrees C) containing 11% EDTA for a period of 48 h (30 ml/g tissue) and was then transferred into freshly prepared PBS + 1% GA solution at 37 degrees C for another 3 days. To investigate the calcification rate, pericardial patches were inserted into the dorsal pouches of 25 male Wistar rats for 21 days. Calcium levels were measured with an atomic absorption spectrophotometer and examined histo-pathologically. The calcium content of EDTA-treated pericardium (Group II), 21 +/- 3.8 microg/mg, was significantly lower than that of Group I, 43.3 +/- 9.2 microg/mg. Assessment of the degree of calcification in the histological sections generally agreed well with the results of the chemical analyses. Calcium deposition in Group I samples were found to be solid mineral depositions, whereas in the Group II pericardial samples, only smaller traces of calcium were found. Calcific degeneration in bovine pericardium can be reduced by using chelates such as EDTA.

Leaflet escape in a TRI bileaflet rotatable mitral valve

Acute prosthetic valve dysfunction is a critical condition for any patient, and is associated with a high mortality. A 24-year-old man who had undergone mitral valve replacement with a TRI bileaflet valve four months previously at another center was admitted with acute-onset left ventricular failure. Echocardiography showed massive mitral insufficiency which was suggestive of a stuck valve. Emergency surgery was carried out, at which the cranial leaflet was found to be stuck open. There was no tissue impingement and thrombosis, the caudal leaflet was absent, and there were no signs of endocarditis or pannus formation. The TRI valve was removed and a replacement 25 mm bileaflet mechanical valve inserted. The embolized leaflet was found in the terminal aorta, but the patient died on day 66 after surgery due to sepsis which had developed from aspiration pneumonia. This is the first report of leaflet escape and terminal aortic embolization with the TRI bileaflet rotatable mitral valve. Acute deterioration of a patient with a prosthetic heart valve should suggest valve dysfunction for which appropriate treatment is rapid relief of the failing left ventricle and replacement of the defective valve with a functioning prosthesis.

Inhibition of calcification with citric acid in pericardial bioprosthetic heart valve material: a preliminary report

BACKGROUND AND AIM OF THE STUDY

Although current bioprosthetic heart valves have low thrombogenicity and favorable hemodynamic properties, their durability remains unsatisfactory. Valve failure usually occurs from calcific degeneration. The study aim was to investigate the effect of a chelating agent, citric acid (CA), on calcification in bovine pericardium.

METHODS

Freshly excised bovine pericardium was dissected free from adhering fat tissue and cut into 1- cm2 pieces; these were rinsed in phosphate-buffered saline solution (PBS), transferred into +4 degrees C PBS containing 0.625% glutaraldehyde (GA) for initial fixation, and then allocated to two groups. Control samples received the same treatment in a fresh solution for 5 days. The other samples underwent an additional fixation step in PBS (pH = 7.4, 37 degrees C) containing 3.8% CA for a period of 48 h (30 ml/g tissue) and were then transferred into freshly prepared PBS + 0.625% GA solution at 37 degrees C for a further 3 days. To investigate calcification rate, pericardial patches were inserted into the dorsal pouches of 15 juvenile male Wistar rats for 42 days. Tissue calcium levels were measured with atomic absorption spectrophotometer, and also assessed histopathologically.

RESULTS

The calcium content of CA-treated pericardium was significantly lower than that of controls (66.4 +/- 33.5 and 111.4 +/- 27.2 mg/g, respectively; p = 0.000). In general, the degree of calcification in histological sections agreed well with results of the chemical analyses. Control pericardial tissues showed moderate to severe solid mineral depositions, predominantly parallel to the implant surface, whereas only minor traces of calcium were found in CA-treated tissues.

CONCLUSION

These preliminary data suggest that calcific degeneration in bovine pericardium may be reduced by using CA as a chelating agent.

N-acetylcysteine for preventing pump-induced oxidoinflammatory response during cardiopulmonary bypass

PURPOSE

To investigate the effect of N-acetylcysteine on preventing pump-induced oxidoinflammatory response during cardiopulmonary bypass (CPB).

METHODS

Forty patients undergoing coronary artery bypass grafting (CABG) were randomly divided into a study group (n = 20), given 50 mg kg(-1) N-acetylcysteine intravenously for 3 days, and a control group (n = 20) given saline. Serum samples were collected for measurement of myeloperoxidase (MPO), malondialdehyde (MDA), interleukin-6, Alpha1-acid glycoprotein (AAGP), and C-reactive protein (CRP) during surgery and postoperatively.

RESULTS

The MPO and MDA values showed a similar pattern during and after CPB in the study group, with significantly less variance than in the control group. Interleukin-6 showed similar patterns in the two groups, but the data from 30 min after the start of CPB and from 6 h post-CPB were significantly different. The AAGP and CRP values were both elevated during CPB in the two groups without a significant difference, but 6 and 24 h post-CPB, the values were significantly higher in the control group than in the study group.

CONCLUSIONS

N-Acetylcysteine decreased pump-induced oxidoinflammatory response during CPB, suggesting that it could be a novel therapy for assisting in the prevention of CBP-induced oxidoinflammatory damage.

Effects of Daflon on oxidative stress induced by hindlimb ischemia/reperfusion

The objective of this study was to investigate the effects of Daflon 500 mg on tissue damage in kidney after ischemia/reperfusion hindlimb, by assessing blood biochemical assay and histopathological analysis. Rats were given Daflon 80 mg x kg(-1) x day(-1) for 10 days. On 11th day of treatment, 4h ischemia followed by 4 h reperfusion period was performed on right hind limb of the rats. Control groups were given only arabic gum and were subjected to same ischemia/reperfusion period. At the end of reperfusion period, erythrocyte superoxide dismutase, Na(+)-K(+) ATPase and reduced glutathione levels were increased in the rats erythrocytes in Daflon group (P<0.01, for all). On the other hand, serum myeloperoxidase and malondialdehyde levels were significantly lower in the Daflon-received rats (P<0.01, for all). Histopathological studies demonstrated that, there was a prominent tubulointerstitial injury with loss of brush border and this degeneration was accompanied by segmental glomerular degeneration also for both control and Daflon group. Daflon-received group animals displayed significantly less periglomerular and perivascular leukocytic infiltration (P=0.015). These overall results suggest that Daflon contributes renal protection from hind limb ischemia/reperfusion injury in some degree, by decreasing systemic oxidative stress.

The protective effect of N-acetylcysteine on apoptotic lung injury in cecal ligation and puncture-induced sepsis model

Apoptotic loss of parenchymal cells may lead to organ dysfunctions in critically ill patients with septic states. As an antioxidant, the protective effects of N-acetylcysteine (NAC) are documented in many experimental and clinical studies. In this experimental study, we investigated the role of chronically used NAC in septic lung injury on a cecal ligation and puncture (CLP) model. To evaluate this, 30 male Wistar rats were randomly divided into four groups as sham (n = 7), CLP (n = 8), sham + NAC (n = 7) and CLP + NAC (n = 8) groups. NAC was administered 150 mg kg(-1) day through intramuscular route beginning 6 h after the operations and lasting for a period of 1 week. One week later, histopathology and epithelial apoptosis were assessed by hematoxylin-eosin and immunohistochemically by M30 and caspase 3 staining to demonstrate septic lung injury. Additionally, lung tissue myeloperoxidase (MPO) activity, malondialdehyde (MDA), and nitrite/nitrate levels were measured. The MPO activity and MDA levels in lung homogenates were found to be increased in CLP group and the administration of NAC prevented their increase significantly (P < 0.05). However, there were no significant differences among the groups regarding nitrite/nitrate levels. The number of apoptotic cells was significantly lower in CLP+NAC group than CLP group, and this finding was supported by M30 and caspase 3 expression in lung (P < 0.05). Lung histopathology was also protected by NAC in CLP-induced sepsis. In conclusion, the chronic use of NAC inhibited MPO activity and lipid peroxidation, which resulted in reduction of apoptosis in lung in this CLP model. Because lung tissue nitrite/nitrate levels did not change significantly, organs other than the lungs may be responsible for producing the increased nitric oxide during sepsis. The chronic use of NAC needs further investigation for its possible antiapoptotic potential in septic states besides its documented antioxidant and antiinflammatory effects.

3-Nitrotyrosine in atherosclerotic blood vessels

The effect of peroxynitrite on the development of atherosclerosis is one of the major foci of recent studies. Here, the cytotoxic effect of peroxynitrite was investigated by quantitatively measuring nitrated tyrosine, 3-nitrotyrosine (3-NT) levels in atherosclerotic blood vessels. Atherosclerotic vessels were obtained from the patients who underwent either coronary artery or peripheric artery bypass surgery. Internal thoracic arteries of the patients were treated as non-atherosclerotic control vessels. 3-NT was measured by reverse-phase HPLC and plasma nitrite-nitrate levels were measured by spectrophotometry. 3-NT levels were significantly elevated in atherosclerotic vessels (46.6 +/- 23.3 nmol/mg protein, n = 15; p < 0.001) in comparison to control vessels (15.8 +/- 2.5 nmol/mg protein, n = 10). Vessel 3-NT correlated weakly with plasma nitrate levels (r = 0.38). Thus, atherosclerotic arteries have higher 3-NT levels than non-atherosclerotic blood vessels.

Effects of trimetazidine on tissue damage in kidney after hindlimb ischemia-reperfusion

The objective of this study was to investigate the effects of trimetazidine (TMZ) on tissue damage in kidney after hindlimb ischemia-reperfusion (I/R), by assessing blood biochemical assay and histopathological analysis. Adult male Wistar rats were divided into two groups. TMZ 10 mg kg(-1)day(-1) was administrated twice a day for 10 days to the treatment group (group T, n=10). Sham group was given only 5% gum arabic (group S, n=10). On 11th day of treatment, 8h I/R period was performed on right hindlimb of the rats. At the end of reperfusion period, a 5 ml blood withdrawn from ascending aorta for biochemical assays and their right kidneys were harvested for histopathological examination. Superoxide dismutase, Na(+)-K(+) ATPase, and reduced glutathione levels were significantly increased in group T (P<0.001). On the other hand, myeloperoxidase and malondialdehyde levels were significantly less in group T than group S (P<0.001). Kidneys from the sham-operated group displayed intense leukocytic infiltration in histopathological examination. These overall results strongly suggested that TMZ contributes renal protection from hindlimb I/R injury by decreasing systemic oxidative stress.

Decreased serum total antioxidant status and erythrocyte-reduced glutathione levels are associated with increased serum malondialdehyde in atherosclerotic patients

BACKGROUND

Coronary artery disease is the significant cause of morbidity and mortality today. The treatment of coronary artery disease is improving, but its prevalence is increasing. Both primary and secondary prevention measures are of vital importance.

METHODS

In this study, vitamin C, total antioxidant status, malondialdehyde in serum and erythrocyte-reduced glutathione levels were investigated in patients with atherosclerosis and compared with those of controls. Levels of serum MDA, vitamin C, total antioxidant status, and erythrocyte-reduced glutathione were determined according to the methods of Yagi, Bauer et al., Miller et al., and Beutler, respectively.

RESULTS

Erythrocyte-reduced glutathione, serum vitamin C, total antioxidant status, and malondialdehyde values of both patients with atherosclerosis and controls were as follows: 2.80 +/- 0.76, 5.82 +/- 0.67 micromol GSH/g Hb; 1.00 +/- 0.19, 1.62 +/- 0.30 mg/dL; 0.86 +/- 0.14, 1.43 +/- 0.16 mmol/L, and 4.26 +/- 0.9, 1.02 +/- 0.80 nmol/mL, respectively. There was a decrease in the levels of serum vitamin C, erythrocyte-reduced glutathione, and total antioxidant status (p <0.001), and increase in the levels of serum malondialdehyde (p <0.001) in patients with atherosclerosis when compared with those of controls.

CONCLUSIONS

Because treatment of atherosclerosis is improving, our results suggest that antioxidant agents may have preventive roles in the formation of atherosclerosis.

A human heterotopic transplant on the beating heart: an interim report of a successful technique performed at Kocaeli University

Heterotopic heart transplantation is still indicated in selected patients mainly with pulmonary vascular bed problems. Cardio-pulmonary bypass (CPB) has well known deleterious effects on the pulmonary vascular bed due to leukocyte sequestration as well as on the immune response of the patients. Also the negative effects of the cardioplegia on the native heart is another drawback of the classical heterotopic heart transplantation with the use of CPB. We want to present our new implantation technique for heterotopic heart transplantation without CPB, used successfully in our institution at the Kocaeli University on a patient with resistant pulmonary hypertension and dilated cardiomyopathy.

In vitro hydrodynamic characteristics of DE-T2 biological heart valve prosthesis

Our goal was to evaluate the DE-T2 biological heart valve prosthesis in our own pulse duplicator system. Pressure drop measurements were made across DE-T2 biological aortic valve size 21. All the pulsatile flow experiments were conducted in the Marmara Research Center pulse duplicator system. The pulsatile flow pressures were measured with Motorola MPX5100DP 9306 transducers, interfaced to Vishay 4270A, 4280, 4290, bridge amplifiers and Motorola System 4000. The valve DE-T2 had a vitellium ring with a central bar. The sewing ring was covered with bovine pericardium that continued to form the leaflets. A special incision was made in the pericardium at a 90 degrees angle to the central bar for the formation of two non-anatomical leaflets. The biological aortic valve prosthesis DE-T2 is similar to the natural aortic valve in systolic function. The closing volume is a little higher than the natural valve. Studies are continuing with the aim of diminishing the closing volume and searching for the ideal preservation solution for the pericardium.