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Biomedical subjects

R Aslan

Publications and source records attributed to R Aslan.

11 recordsLinked to original sources
PubMed2001

Influence of noise exposure on antioxidant system and TEOAEs in rabbits.

Noise exposure may cause hearing loss. The precise mechanism leading to cochlear damage in aco trauma is not known. Eight rabbits were used in this study. Transient evoked otoacoustic emissions (TEOAEs) were recorded in all animals and blood malondialdehyde (MDA) and glutathione (GSH) levels were determined. All rabbits were then exposed to 100 dB SPL broadband noise for 1 h. TEOAEs were recorded again and blood MDA and GSH levels determined following noise exposure. The reproducibility scores of the TEOAE measurements were found to be significantly lower (P < 0.01), whereas the amplitudes and signal-to-noise values of emissions decreased (P > 0.01) in rabbits exposed to noise. The TEOAE energies were poor at 4 kHz. During this threshold shift, GSH blood levels decreased and MDA levels increased,indicating that there is a close relationship between noise-induced hearing loss and the antioxidant system. These findings indicate that TEOAE recording is an excellent test for detecting effects of noise on hearing.

Animals↗
PubMed1999

Measurement of troponin T to detect cardioprotective effect of trimetazidine during coronary artery bypass grafting.

BACKGROUND: The aim of the present study was to evaluate potential myocardial protection by trimetazidine by measurement of the cardiac marker protein troponin T (TnT) during coronary bypass operations. METHODS: We conducted a double-blind, placebo-controlled study on 30 randomized patients who had aorta-coronary artery bypass operations. The TMZ group was composed of 15 patients and the placebo group of 15 patients in New York Heart Association class III or IV. Pretreatment was started 3 weeks preoperatively with trimetazidine (60 mg orally per day) or the placebo. In the trimetazidine TMZ group, there were 2 women and 13 men with a mean age of 57.1+/-2.2 years and mean cross-clamp time of 44+/-1.8 minutes. In the placebo group, there were 5 women and 10 men with a mean age of 58.4+/-1.2 years and a mean cross-clamp time of 42+/-2.4 minutes. Serial blood samples were collected before and after the operation, and serum concentrations of cardiac TnT were measured. RESULTS: The preoperative serum concentration of TnT was 0 to 0.39 ng/mL in all patients. The mean TnT levels were measured 5 minutes after completion of cardiopulmonary bypass (1.5+/-0.3 ng/mL) and 12 (1.4+/-0.1 ng/mL), 24 (0.9+/-0.1 ng/mL), and 48 hours postoperatively (0.1+/-0.1 ng/mL) in the trimetazidine group. Troponin T levels in the placebo group measured at the same time periods were 4.4+/-0.4, 4.8+/-0.7, 2.8+/-0.4, and 0.7+/-0.1 ng/mL. In the trimetazidine group, TnT levels were significantly less than those of the placebo group (p < 0.001). The levels of TnT were tested by creatine kinase-MB levels of both groups. Mean cardiac index was evaluated in all patients preoperatively and postoperatively. There was no significant difference in perioperative hemodynamics (blood pressure and cardiac index) between groups. CONCLUSIONS: These results obtained by measurement of cardiac TnT suggested that pretreatment with trimetazidine reduces ischemic-reperfusion damage during coronary bypass operations but did not affect postoperative hemodynamics.

Cardiopulmonary Bypass↗
PubMed1999

The effects of methylprednisolone on complement, immunoglobulins and pulmonary neutrophil sequestration during cardiopulmonary bypass.

In this study, the authors administered high dose (30 mg/kg body weight i.v.) methylprednisolone before cardiopulmonary bypass to observe the effects on complement, immunoglobulins and pulmonary neutrophil sequestration. Fifty patients undergoing valve replacements were included in this study. Patients were divided into two groups: group I (20 patients) served as control and did not receive methylprednisolone, group II (30 patients) received methylprednisolone. Blood samples for complements (C3c and C4) were taken, before cardiopulmonary bypass, at 5, 10 and 30 min intervals from the end of cardiopulmonary bypass, after reversal of heparin with protamine infusion, and after skin closure. Blood samples for immunoglobulins were taken before cardiopulmonary bypass, 30 min after onset of cardiopulmonary bypass and after skin closure. After onset of cardiopulmonary bypass, all C3c and C4 levels decreased in both groups. There was a significant decrease in C4 levels at end of cardiopulmonary bypass and after protamine infusion in group I compared with group II (P < 0.05). C3c levels in group I decreased significantly compared with group II after 30 min of cardiopulmonary bypass and after protamine infusion (P < 0.05). All immunoglobulin (IgG, IgM, IgA) levels were decreased in both groups, but the decrease in IgG was statistically significant after skin closure in group I compared with group II (P < 0.05). Pulmonary neutrophil sequestration was higher in the control group compared with the methyl-prednisolone group (P < 0.05). In conclusion, methylprednisolone administration before cardiopulmonary bypass may prevent the harmful effects of complement activation, immunoglobulin denaturation and neutrophil sequestration in the pulmonary capillary system.

Adult↗
PubMed1999

Clinical, biochemical and histochemical assessment of pretreatment with glucose-insulin-potassium for patients undergoing mitral valve replacement in the third and fourth functional groups of the New York Heart Association.

In this study, the potentially beneficial effects of preoperative treatment with glucose, insulin and potassium in a randomized series of 30 consecutive patients undergoing mitral valve replacement, who were in the third and fourth functional groups of the New York Heart Association scale, were investigated. Fifteen patients received glucose, insulin and potassium, and 15 patients received the same volume of normal saline. The characteristics of the groups did not differ. Papillary muscle-biopsy samples were obtained at the time of surgery and analysed for glycogen, both biochemically and histochemically. The clinical course of all patients was monitored closely during the first 24 hours after surgery. The patients receiving glucose, insulin and potassium had higher glycogen levels (43 +/- 13.54 micromol/g) (P < 0.001). In addition, they required less inotropic pharmacological support (scored by the Gradinac method), had fewer ventricular arrhythmias and exhibited improved haemodynamic indices: cardiac output increased (P < 0.025 to P < 0.005), while systemic vascular resistance decreased (P < 0.001). Pretreatment with glucose, insulin and potassium did not, however, affect the patients' postoperative wedge pressure and mortality. The results of this study suggest that glucose, insulin and potassium pretreatment may be beneficial in unfit patients undergoing mitral valve replacement.

Adult↗
PubMed1997

Investigation of malondialdehyde formation and antioxidant enzyme activity in stored blood.

In the present study, fresh blood obtained from six healthy adult male donors was investigated for erythrocyte malondialdehyde (MDA) formation and antioxidative enzyme activity. Plasma and erythrocyte membrane lipid peroxidation were measured by MDA formation. Erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were determined in whole blood stored for transfusion purposes. Erythrocyte and plasma MDA levels increased significantly during the storage period from day 3 to day 19 and, after that, stayed unchanged. Erythrocyte MDA increased 100% on day 7 when compared to day 1. The GSH-Px activity significantly decreased after day 9 and SOD decreased after day 13. The reduction in enzyme activities continued until day 27. Our results showed significant alteration in erythrocyte membrane and plasma MDA formation and intracellular antioxidant enzyme status in whole blood used for transfusion. However, we do not know whether such alterations have clinical importances for the recipient.

Adult↗
PubMed1996

Effects of aprotinin on plasma levels of neutrophil elastase and postoperative blood loss in cardiac surgery.

This study evaluated the effects of aprotinin on plasma levels of elastase, platelet count, fibrinogen levels and postoperative bleeding. Thirty cardiac surgery patients were randomly chosen for this study. The protease inhibitor aprotinin was given in high doses to 20 patients before and during cardiopulmonary bypass; 10 patients served as the control group. Mean patient age and body weight was similar in both groups. There were no significant inter-group differences in the total cardiopulmonary bypass and cross-clamp times. Mean (s.e.m.) elastase levels were significantly raised in the control group (161.9(2.57) micrograms/l) compared with the treated group (148.2(3.29) micrograms/l) at 30 min of cardiopulmonary bypass (P < 0.01) and rose even further at the end of cardiopulmonary bypass, after protamine infusion, and 24 h postoperatively (P < 0.001). Platelet counts decreased more in the control group (P < 0.001). Serum fibrinogen levels were significantly lower in the controls during and just after cardiopulmonary bypass (P < 0.01). Postoperative blood loss was significantly less in the aprotinin-treated patients (315(25) ml) compared with the controls (589(154) ml) (P < 0.05). Aprotinin appears to inhibit elastase release and decrease postoperative blood loss.

Adult↗
PubMedDate not supplied

Magnesium-flush infusion into the aortic root just before reperfusion reduces the requirement for internal defibrillation and early post-perfusion arrhythmias.

Pre- and post-operative administration of magnesium has beneficial effects on post-operative ischaemia and reperfusion arrhythmias, but few studies have examined whether intra-operatively administered magnesium can prevent the effects of intra-operative arrhythmias. The aim of this randomized, double-blind study was to compare the effects of intra-operative magnesium or placebo on intra-operative arrhythmias in patients undergoing coronary bypass grafting. Patients received a flush infusion of magnesium or placebo into the aortic root before cross-clamp removal. The results showed that rate of spontaneous resumption of a cardiac rhythm was significantly higher, and number of shocks for defibrillation, energy requirement for defibrillation and rate of intra-operative ventricular tachyarrhythmias were significantly lower in the magnesium group, compared with the placebo group. The differences in need for temporary pacing, and in serum magnesium levels, were not significant. Intra-operative administration of magnesium has beneficial effects on the outcome of surgery. Larger, multicentre clinical investigations should now be undertaken.

Aged↗
PubMedDate not supplied

An alternative, less invasive approach to median sternotomy for cardiac operations in adults: right infra-axillary minithoracotomy.

We compared the use of right infra-axillary minithoracotomy and conventional median sternotomy in direct open-heart surgery in 59 adults undergoing elective surgery for mitral valve stenosis, mitral valve disease, atrial septal defect repair, left atrial myxoma excision or mitral and tricuspid valve disease. Patients were randomized to the infra-axillary minithoracotomy group (Group A; n = 29) or the median sternotomy group (Group B; n = 30). Post-operative outcomes (post-operative bleeding; cross-clamp time; length of hospital and intensive care unit stays; and post-operative blood transfusion and analgesic requirements) were recorded and compared; they were found to be significantly lower in Group A than Group B. We concluded that right infra-axillary minithoracotomy is less invasive and can be used safely in adults as an alternative approach to conventional median sternotomy for some cardiac operations. Further multicentre studies in adults are now needed.

Adult↗
PubMedDate not supplied

The factors effecting complement activation in open heart surgery.

The activation of the complement system was investigated in 10 patients with rheumatic valve disease having heart surgery. The C3c, C4, leukocyte count and polymorphonuclear neutrophil count were determined in the blood samples taken before anaesthesia, after anaesthesia, 10 minutes after protamine administration and after the closure of the skin incision. In addition, atrial blood samples were taken after the release of the cross-clamp and pulmonary neutrophil trapping was investigated. In this study C3c and C4 consumption was found to take place after 30 minutes of CPB (cardiopulmonary bypass) and 10 minutes after protamine administration; the affects of anaesthesia and heparin were not significant.

Adult↗
PubMedDate not supplied

Human umbilical cord vein grafts for replacement of the superior vena cava.

We have used umbilical veins as experimental graft materials for superior vena cava replacement. The patency rate of these grafts in 25 laboratory animals was 96%; the mortality and graft thrombosis rate was 4%. Histopathologically, no evidence of rejection was detected in the graft material. These results suggest that umbilical veins are superior to other prosthetic materials as grafts in venous surgery.

Animals↗