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Biomedical subjects

O Akyol

Publications and source records attributed to O Akyol.

At least 19 recordsLinked to original sources
PubMed2005

The effect of Nigella sativa oil against experimental allergic encephalomyelitis via nitric oxide and other oxidative stress parameters.

Reactive oxygen species (ROS) including nitric oxide (NO) are thought to be involved in inflammatory processes, exacerbating inflammation and tissue damage in multiple sclerosis (MS). The oil extracts of Nigella sativa (N. sativa) has been known as an antioxidant and antiinflammatory agent. The aim of the present study was to investigate the hypothesis that N. sativa components provide protection against oxidative stress induced by experimental autoimmune encephalomyelitis (EAE) in rats. For this purpose, EAE was induced in rats by using guinea pig myelin basic protein (MBP) in Freud's adjuvant with addition of heat-killed M. Tuberculosis H37Ra to test this hypothesis. In study groups, N. sativa was given by oral gavage to the rats. Treatment of the rats with N. sativa inhibited ROS production induced by EAE showing diminished levels of MDA of both brain and medulla spinalis tissues. Although there was a significant decrease in brain NO level, there was an increase in medulla spinalis NO level after EAE induction in rats. N. sativa regulated tissue NO levels in some extend when applied together with EAE. When N. sativa was given alone to the rats, no changes were shown in brain, medulla spinalis, and serum oxidant/antioxidant parameters. In conclusion, N sativa may protect brain and medulla spinalis tissues against oxidative stress induced by EAE. In addition, N. sativa display its antioxidant and regulatory effects via inflammatory cells rather than the host tissue (brain and medulla spinalis) for EAE in rats.

Animals↗
PubMed2004

Erdosteine ameliorates neurological outcome and oxidative stress due to ischemia/reperfusion injury in rabbit spinal cord.

OBJECTIVE: Oxygen-derived free radicals have been suggested as important in degeneration after spinal cord ischemia. The aim of this study was to investigate whether erdosteine has a protective effect against spinal cord ischemia during aortic cross clamping. MATERIALS AND METHODS: New Zealand White rabbits (n=21) were divided into three groups. In the ischemia/reperfusion group (I/R) (n=8), the infrarenal aorta of rabbits was cross clamped for 21 min and then reperfused. In erdosteine group, the administration of erdosteine solution (50 mg/kg) was started two days before aortic cross-clamping and rabbits (n=8) were subjected to ischemia and reperfusion. Animals in control group (n=5) underwent a surgical procedure similar to the other groups but the aorta was not clamped. The animals were sacrificed at 72 h and histopathological, and biochemical analyses were carried out on the lumbar spinal cords. RESULTS: Erdosteine treatment was associated with improved neurological function in the postoperative period. Histopathological examination of spinal cord tissues in erdosteine group revealed changes consistent with mild ischemic injury, but rabbits in I/R group with paraplegia had total destruction of the motor neurons. Biochemical analyses of spinal cord tissues, in the I/R group, revealed a significant increase in the superoxide dismutase, xanthine oxidase, adenosine deaminase and myeloperoxidase activities, and a significant depletion in glutathione peroxidase activity when compared to that of control rabbits. Erdosteine treatment prevented the increase of all these enzymes except adenosine deaminase. Ischemia/reperfusion produced a significant increase in the tissue malondialdehyde levels. Ischemia/reperfusion-induced increments in malondialdehyde content of the spinal cord were significantly prevented by erdosteine treatment. CONCLUSIONS: The present study demonstrated that erdosteine treatment before aortic cross clamping ameliorates neurological outcome, neuronal injury and oxidative stress in the rabbit spinal cord.

Adenosine Deaminase↗
PubMed2004

Caffeic acid phenethyl ester ameliorated ototoxicity induced by cisplatin in rats.

Caffeic acid phenethyl ester (CAPE), an active component of propolis, exhibits antioxidant properties. This experimental study was designed to determine the effect of CAPE on ototoxicity induced with cisplatin. Twenty-four adult Wistar albino rats were divided into four groups: cisplatin (n=6), saline (n=6), CAPE (n=6), and cisplatin plus CAPE (n=6). Rats were tested before and 5 days after cisplatin treatment with or without chemo protection. The Distortion Product Otoacoustic Emissions (DPOAEs) were elicited from the control and experimental animals utilizing the standard commercial Otoacoustic Emission (OAEs) apparatus. The animals in all groups were sacrificed under general anesthesia on the fifth day following last OAE measurements. For biochemical investigations, the blood samples were drawn from inferior vena cava. On day 0, the initial baseline DPOAEs measurement results presented similar values while comparing the groups in drug free phase (p>0.05). On day 5, intrasubject measurement parameters of DPgrams and I/O functions of cisplatin group were significantly deteriorated (p<0.05). The second measurements of the other groups revealed no significant differences between their DPgrams and I/O functions in all frequencies (p>0.05). Among the biochemical parameters, plasma xanthine oxidase (XO) activity was found to be more elevated in the cisplatin group than the saline group (p<0.05). CAPE led to more decreased XO activity than cisplatin (p<0.05). The results of this study show that prophylactic administration of CAPE for cisplatin ototoxicity ameliorated hearing deterioration in rats.

Analysis of Variance↗
PubMed2001

Caffeic acid phenethyl ester changes the indices of oxidative stress in serum of rats with renal ischaemia-reperfusion injury.

Oxygen-derived free radicals have been implicated in the pathogenesis of renal injury after ischaemia-reperfusion. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant properties. To investigate whether treatment with either CAPE or alpha-tocopherol modifies the levels of the endogenous indices of oxidant stress, we examined their effects on an in vivo model of renal ischaemia-reperfusion injury in rats. CAPE at 10 micromol kg(-1) or alpha-tocopherol at 10 mg kg(-1) was administered intraperitoneally before reperfusion. Acute administration of both CAPE and alpha-tocopherol altered the indices of oxidative stress differently in renal ischaemia-reperfusion injury.

Adenosine Deaminase↗
PubMed2001

The effect of caffeic acid phenethyl ester on ischemia-reperfusion injury in comparison with alpha-tocopherol in rat kidneys.

Oxygen-derived free radicals have been implicated in the pathogenesis of renal injury after ischemia-reperfusion. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant and anti-inflammatory properties. To determine whether CAPE offers any advantage over alpha-tocopherol, we compared their effects on an in vivo model of renal ischemia-reperfusion injury in rats. CAPE at 10 micromol/kg or alpha-tocopherol at 10 mg/kg was administered intraperitoneally before reperfusion. Acute administration of CAPE suppressed ischemia-reperfusion induced renal lipid peroxidation and tissue injury more than alpha-tocopherol. CAPE may therefore offer a therapeutic advantage in acute injury settings.

Animals↗
PubMed2001

Evidence that the activities of erythrocyte free radical scavenging enzymes and the products of lipid peroxidation are increased in different forms of schizophrenia.

In order to examine antioxidant status and lipid peroxidation in schizophrenia patients, activities of three free radical scavenging enzymes (superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT)), and the level of thiobarbituric acid-reactive substances (TBARS) as an index of lipid peroxidation have been studied in red blood cells. Schizophrenic patients were divided into three groups (disorganized (n = 21), paranoid (n = 26) and residual types (n = 18)) to determine differences between subgroups. SOD, CAT and GSH-Px activities in the control group were found to be 1461.0 +/- 248.6 U g(-1) Hb, 148.2 +/- 59.3 k g(-1) Hb and 25.87 +/- 4.25 U g(-1) Hb, respectively. We found no significant differences in SOD activities between study and control groups. There was a significant increase in SOD activity in the residual group compared to the paranoid group (P < 0.005). CAT activity was found to be increased in disorganized (148%), paranoid (147%), and residual (165%) groups compared to the control group. GSH-Px activity was markedly increased in the study groups except the paranoid group. Statistically significant (3-4 fold) increases in TBARS levels of red blood cells were found in all the study groups. It is proposed that antioxidant status may be changed in schizophrenia and thus may induce lipid peroxidation. Therefore, oxidative stress may have a pathophysiological role in all the subtypes of schizophrenia.

Adolescent↗
PubMed2001

Effects of caffeic acid phenethyl ester and epidermal growth factor on the development of caustic esophageal stricture in rats.

BACKGROUND/PURPOSE: An experimental study was performed to modify the healing response in caustic esophageal burns to prevent stricture development. Two different agents with different modes of actions, caffeic acid phenethyl ester (CAPE) and epidermal growth factor (EGF), were studied. CAPE has antiinflammatory, immunomodulatory, antioxidant, and antimitotic properties. EGF has known properties in supporting wound healing and in protecting esophagus from injuries. METHODS: The model described by Gehanno and its modification by Liu was used to create standard esophageal burns with 50% NaOH. The study was performed with 76 rats in 4 main groups (sham, CAPE, EGF, and control) and 2 subgroups in each for 5 and 28 days of observation. Efficacy of treatment was assessed in 28-day subgroups by measuring weight gain, contrast esophagograms on day 27, histologic evaluation by measuring stenosis index (wall thickness/lumen diameter), and collagen deposition, and biochemically by determining tissue hydroxy proline (OHP) content. RESULTS: In the end of the study, increase rates of mean body weights of the animals in the 28-day subgroups were as follows: sham, 30%; CAPE, 23%; EGF, 22%; and control, 14%. Although all the animals in subgroups significantly gained weight, the mean weight gain was significantly low in controls when compared with sham, CAPE, and EGF groups (P <.05). Contrast esophagograms on day 27 showed no stenosis in the sham, mild stenosis in CAPE and EGF, and severe stenosis with proximal dilatation in controls. Stenosis indices of the subgroups were as follows: sham, 0.29; CAPE, 0.41; EGF, 0.41; control, 0.84. Index was significantly higher in controls (P <.05). Collagen accumulation scores in the esophageal wall were as follows: Sham, 0.0; CAPE, 0.87; EGF, 0.30; control, 2.70. Scores also were significantly higher in controls (P <.05). Tissue (OHP) levels were as follows (mg/g dry tissue): Sham, 1.48; CAPE, 1.53; EGF, 1.90; control, 4.01. Production of OHP was significantly higher in controls. CONCLUSIONS: The results of the parameters in the study indicate that administration of CAPE and EGF has beneficial effects in the prevention of caustic esophageal strictures. Those effects of CAPE may occur through its antiinflammatory, immunomodulatory, and antioxidant properties, and EGF may occur through its induced proliferative properties on the esophagus.

Animals↗
PubMed2001

Plasma malondialdehyde and nitric oxide levels in age related macular degeneration.

AIMS: To evaluate alteration of plasma malondialdehyde (MDA) and nitric oxide (NO) levels in patients with exudative age related macular degeneration (ARMD). METHODS: Plasma nitrite plus nitrate concentrations as an index of plasma NO levels and plasma MDA level as a marker of lipid peroxidation were measured in patients with exudative ARMD and age and sex matched healthy subjects. RESULTS: Significantly higher MDA and lower NO levels were detected in plasma of patients with ARMD compared with their controls (p=0.01, p=0.001, respectively). CONCLUSION: The results may support involvement of oxidative damage and vascular theory in the pathogenesis of ARMD as part of the ageing process.

Aged↗
PubMed2000

Testicular nitric oxide levels after unilateral testicular torsion/detorsion in rats pretreated with caffeic acid phenethyl ester.

Nitric oxide (NO) plays an important role in modulating blood flow in normal and in several pathological conditions, and its levels seem to change with ischemia-reperfusion injuries. Caffeic acid phenethyl ester (CAPE), an active component of propolis, exhibits antioxidant properties. This experimental study was designed to determine the changes in NO levels and the effect of CAPE on NO levels after testicular torsion/ detorsion in rats. Thirty-five adult male albino rats were divided into four groups: sham operation (n = 8), torsion (n = 9), saline/detorsion (n = 9), and CAPE/detorsion (n = 9). Rats in the sham operation group were killed after the testes were handled without torsion. Rats in the torsion group were killed after 720 degrees clockwise testicular torsion for 2 h. CAPE was administered 30 min before detorsion in the CAPE/detorsion group and saline was administered in the saline/detorsion group. After 4 h of testicular detorsion in both of these groups, the rats were killed and bilateral orchiectomy was performed to determine the tissue levels of NO. The level of NO in the torsion group (113.77 +/- 33.18 nmol/g protein) was significantly higher than that of the sham operation group (64.53 +/- 29.64 nmol/g protein). In the saline/detorsion group, the NO level (31.26 +/- 12.58 nmol/g protein) was significantly lower than in the torsion and sham operation groups. CAPE administration in the CAPE/detorsion group seemed to raise the NO level (72.63 +/- 23.87 nmol/g protein) above the level of the sham operation group. Contralateral testes were not affected by the torsion/detorsion processes performed on the ipsilateral testes. These results show that NO levels increase with torsion and decrease with detorsion. CAPE administration seems to increase tissue NO levels and this may be important for protecting the testes from torsion/detorsion injuries.

Animals↗
PubMed2000

Plasma superoxide dismutase activity and malondialdehyde level correlate with the extent of acute appendicitis.

Although the mechanism of acute appendicitis (AA) is partly understood, the progression following the onset of inflammation has not yet been clarified. To determine oxidative activities in the plasma of patients with AA, superoxide dismutase (SOD) activities and malondialdehyde (MDA) levels were measured in samples from 31 patients diagnosed as having AA and 10 otherwise healthy children with inguinal pathologies. The patients with AA were divided into three subgroups: acute focal (AFA) (n = 8), acute suppurative (ASA) (n = 9), and acute perforated appendicitis (APA) (n = 14), according to the intraoperative findings and histopathologic examination. SOD and MDA were compared statistically between these subgroups and between them and the control group. Additionally, mean leukocyte counts of each group were determined and the differences between the groups were evaluated. Both SOD and MDA were significantly higher in the ASA and APA groups compared to controls and AFA group. The mean leukocyte numbers of the ASA and APA groups were significantly higher compared to the AFA group. Based to these results, it may be speculated that oxygen free radicals (OFR) may play an important role in the extent of AA. To prevent the hazardous effects of OFR, the organism may increase SOD and other antioxidant enzyme levels and/or activities.

Acute Disease↗
PubMed2000

Concentrations of copper, zinc and various elements in serum of patients with bronchial asthma.

In this study, serum copper, zinc, magnesium, iron and calcium concentrations were investigated in 40 patients with bronchial asthma (BA) and in 43 healthy subjects. Copper and calcium levels were found to be increased in patients with BA compared to the control group (p < 0.001 and p < 0.001 respectively). On the other hand, the serum zinc level was significantly lower in healthy subjects (p < 0.01). No changes were found in serum magnesium and iron levels in patients with BA compared to controls. In addition to various elements, certain serum proteins such as albumin, transferrin and ferritin were also assessed to determine whether there was a relationship between the elements and proteins in patients with BA. There was only a significant decrease in albumin concentration in patients with BA (p < 0.05).

Adolescent↗
PubMed1999

Caffeic acid phenethyl ester prevents intestinal reperfusion injury in rats.

BACKGROUND/PURPOSE: Ischemia-reperfusion injury is encountered frequently in conditions that diminish intestinal blood flow. Caffeic acid phenethyl ester (CAPE), which is a specific component of the honeybee hive product propolis, exhibits potential antioxidant properties. This experimental study was designed to determine the effect of CAPE on ischemia-reperfusion injury in rat intestine. METHODS: Fifty rats were divided into 5 groups; sham (SH), saline ischemia (SI), saline reperfusion (SR), CAPE ischemia (CI), and CAPE reperfusion (CR). Either CAPE, 10 micromol/kg, or saline was administered intraperitoneally 30 minutes before ischemia. Intestinal ischemia for 30 minutes and reperfusion for 60 minutes were applied. Ileum specimens were obtained to determine the tissue levels of malondialdehyde, superoxide dismutase, catalase, and histological changes. RESULTS: Malondialdehyde levels in the CR group did not increase after reperfusion when compared with the CI group. However, statistically significant differences were observed between the SR and SI groups. Additional mucosal injury in the CR group when compared with the CI group was not observed. Whereas, there was a statistically significant increase in mucosal injury in the SR group. Reperfusion did not cause further injuries through both biochemical and histological parameters in the CR group. CONCLUSIONS: Results of this study showed that prophylactic administration of CAPE in ischemic condition prevents reperfusion injuries by eliminating oxygen radicals and inhibiting polymorphonuclear leukocyte infiltration. CAPE may be useful in combating the diseases of oxidative stress.

Animals↗
PubMed1999

The effects of caffeic acid phenethyl ester (CAPE) on spinal cord ischemia/reperfusion injury in rabbits.

OBJECTIVE: Oxygen-derived free radicals have been implicated in the pathogenesis of spinal cord neuronal injury after both trauma and ischemia-reperfusion. Caffeic acid phenethyl ester (CAPE), an active component of propolis extract, exhibits antioxidant properties. This experimental study was designed to determine the effect of CAPE on ischemia-reperfusion of spinal cord in rabbits. METHODS: Forty-one New Zealand white rabbits were used in the study. The animals undergone aortic occlusion were divided into three groups each consisting of 11 rabbits: methylprednisolone (MP), CAPE, and control. CAPE 10 micromol/kg, methyl prednisolone (MP) 30 mg/kg or similar dose saline were injected intraperitoneally before surgical intervention. Animals were subjected to 21 min of cross-clamp time. At the end of occlusion time, the clamps were removed and restoration of the blood flow was verified visually. Animals in sham group (n = 8) underwent a surgical procedure similar to the other groups but the aorta was not occluded. Neurological status was scored by assessment of hindlimb motor function deficit. RESULTS: The scores in CAPE group was different from control groups at 48 h (3.91+/-0.5 vs. 2.91+/-0.7; P = 0.0013). Spinal cord specimens were obtained to determine the tissue levels of malondialdehyde, superoxide dismutase, catalase, and histological changes. Malondialdehyde levels in control group were increased significantly when compared to sham group (124.22+/-24.36 and 41.92+/-10.08 nmol/g wet tissue, P = 0.0003). MDA levels in the CAPE group were lower than MP group and differences between the two groups were statistically significant (56.77+/-15.265 and 107.74+/-19.31 nmol/g wet tissue, P = 0.0001). We did not observe additional tissue injury in CAPE group when compared to control group. SOD and CAT activities were not concordant in all the groups. CONCLUSIONS: These results suggest that CAPE may be an available agent to protect the spinal cord from ischemia-reperfusion injury.

Animals↗
PubMed1999

Serum and hair trace element levels in patients with epilepsy and healthy subjects: does the antiepileptic therapy affect the element concentrations of hair?

In this study, hair magnesium (Mg), zinc (Zn), copper (Cu), and manganese (Mn) levels, and serum Zn and Mg levels were measured by atomic absorption spectrophotometer in patients with epilepsy (n = 33) and healthy subjects (n = 21), and results obtained were statistically compared. The mean hair Cu, Mg, and Zn levels of epileptic patients were significantly lower than the levels of control subjects. There was no significant difference between epileptic patients and control subjects in respect to the mean Mn levels. Mean serum Mg levels in epileptic patients showed significant difference, but serum Zn levels were similar among both groups. When the effects of anticonvulsant therapy on Cu, Zn, Mn, and Mg in the hair, and Mg and Zn in the serum were analyzed in epileptics, there was no significant difference between the patients with or without therapy. Likewise, the mean trace element levels in epileptics showed no significant difference according to the type of antiepileptic drug and seizure, and gender. We suggest that the changed element status (Zn, Mg, and Cu) in hair may play an indicator role in the diagnosis of epileptic patients.

Adolescent↗
PubMed1999

Nickel, chromium, manganese, iron and aluminum levels in human cataractous and normal lenses.

Atomic absorption spectrophotometry was used to detect lenticular nickel, chromium, manganese, iron and aluminum levels in 37 senile cataractous and 9 normal human lenses. The nuclear parts of the lenses were used for the study in both groups. It was found that the concentrations of nickel and iron were significantly higher, and those of chromium, manganese and aluminum were significantly lower in human cataractous lenses than those in normal human lenses. None of the elements showed a significant difference according to sex in both groups. As remarkable differences in chromium, manganese, iron, aluminum and nickel levels exist in cataractous lenses, all the five elements may play some roles in cataractogenesis.

Aged↗