Biomedical subjects

Nevin Ilhan

Publications and source records attributed to Nevin Ilhan.

33 records · Page 2Linked to original sources

PubMed2003

A comparison of estrogen and two different doses of calcitonin in ovariectomized rats.

The purpose of this study was to investigate the treatment efficacies of salmon calcitonin (SC) and estrogen in a type-I osteoporotic rat model. Sixty, 3-month-old, female Wistar rats were divided into six groups. The first group was used as the control, and the second a sham, the other four were surgically ovariectomized. 24 hours after the ovariectomy, they were either left untreated (OVX), or treated with an injection of either 17-beta estradiol (E2) 30 mcg/kg/24 hours, low-dose calcitonin (LDC) 10 IU/ kg/48 hours or high-dose calcitonin (HDC) 20 IU/kg/48 hours. 6 weeks later, the bone densities were measured by DEXA, the animals sacrificed and the femurs harvested for histomorphometric evaluation. The bone mineral densities (BMD) of the spine and proximal femur were lower in the OVX group, but only the values of the spine BMD were statistically significant. The BMD of the spine seemed to be preserved with all the treatments. The histomorphometric evaluation revealed that after the OVX the decrease in the trabecular volume was prevented by all the treatments. However, significant changes in the indices of bone formation were not shown. In conclusion, all the treatments prevented bone lost in the ovariectomized rats. Histopathological measurements of bone formation are unlikely to provide any evidence for the effects of these agents on the osteoblastic function. In the animal model of estrogen depletion, our results suggest that the calcitonin provides an important alternative therapy for postmenopausal osteoporosis.

Animals↗

PubMed2003

Vascular endothelial growth factor and oxidative damage in cancer.

OBJECTIVES: VEGF may be an indicator for the angiogenic potential of a tumor and stimulates NO which plays complex roles in cancer. In our study, we investigated the levels of MDA, NO and VEGF in the plasma of various types cancer patients (untreated, yet). DESIGN AND METHODS: The level of VEGF was determined by using ELISA. Plasma MDA, NO and VEGF levels were measured in 45 patients with various cancer types and in 21 healthy subjects. RESULTS: Plasma MDA and VEGF levels were significantly higher than those of the healthy subjects (p < 0,0001). NO levels of the patients were significantly lower vs. the healthy subjects (p < 0,001). CONCLUSIONS: Increased plasma VEGF and MDA concentrations and decreased plasma NO levels have been found in patients with various types of human cancer. Howewer, the prognostic and clinical significance of plasma VEGF in cancer patients is unknown.

Adult↗

PubMed2003

Free radicals and scavenging enzymes in chronic tonsillitis.

OBJECTIVE: This study aimed to define the relationship between chronic tonsillitis and levels of malondialdehyde and superoxide dismutase in free radical and antioxidant forms. It is suggested that free oxygen radicals may play a role in chronic tonsillitis. Materials and methods One hundred twenty-four patients were enrolled in the study. Tonsillectomy was performed via the usual dissection-snare method. Venous blood was taken preoperatively and at 2 weeks postoperatively. Blood samples and tonsil specimens were evaluated for malondialdehyde and superoxide dismutase analysis. RESULTS: The levels of malondialdehyde and superoxide dismutase in plasma were compared preoperatively and postoperatively, and there were statistically significant differences between these levels (P < 0.05). In contrast, the levels of malondialdehyde and superoxide dismutase in tonsil tissue were not correlated with the plasma levels of malondialdehyde and superoxide dismutase in pretonsillectomy and posttonsillectomy terms (P > 0.05). CONCLUSION: The presence of malondialdehyde and superoxide dismutase in plasma and tonsil tissue reinforces the involvement of oxidative stress in the pathophysiology of chronic tonsillitis.

Adolescent↗

PubMed2003

Plasma malondialdehyde and serum trace element concentrations in patients with active pulmonary tuberculosis.

Increased amounts of reactive oxygen species (ROS) are produced as a consequence of a phagocyte respiratory burst during pulmonary inflammation. The aim of our study was to assess the concentration of malondialdehyde (MDA) and trace metals in patients with active pulmonary tuberculosis (TB). Eighty-three subjects were enrolled into the study and prospectively divided into three groups: 22 subjects with healthy controls (group I), 21 patients with inactive pulmonary TB (group II), and 40 patients with active pulmonary TB (group III). Before beginning the therapy, plasma MDA and serum concentrations of zinc (Zn), copper (Cu), albumin, and iron (Fe) were measured. The concentration of MDA and Cu in group III were higher than in the other groups (p<0.0001). The serum Zn and albumin levels were significantly lower in group III compared with healthy controls (p<0.05). There was a positive correlation between MDA and erythrocyte sedimentation rate (r = +0.647, p<0.0001; Spearman's test). Our data indicated increased circulating levels of MDA and changed serum trace metal levels in active pulmonary TB. Trace metal levels must be closely followed during the diseases process and further studies are needed to assess the role of antioxidants as adjuvant therapy in patients with active pulmonary TB.

Adult↗

PubMed2003

[The effect of vitamin E on histopathologic healing and lipid peroxidation levels in experimentally induced traumatic tympanic membrane perforations].

OBJECTIVES: To examine the favorable effects of vitamin E on tympanic membrane perforations induced mechanically in guinea pigs. STUDY DESIGN: Bilateral tympanic membrane perforations of 1.8 mm were induced in 40 guinea pigs. The animals were randomly divided into two groups equal in number. One group remained untreated, while the other was administered vitamin E (100 mg/kg/day) through intramuscular injections. On days 1, 3, 5, and 7, five animals in each group were randomly sacrificed. Histopathologic changes in the tympanic membranes were evaluated and malondialdehyde levels were determined. RESULTS: Significant increases were observed in epithelial thickness, fibroblastic proliferation, and neovascularization in the study group (p<0.05). Epithelial thickness was found to be increased in both groups beginning from the first day; however, this increase was more rapid in the study group. Although malondialdehyde levels showed significant increases on days 3 and 5 in both groups (p<0.05), they returned to the first day values in vitamin E-treated animals on day 7, whereas controls still maintained high malondialdehyde levels. CONCLUSION: Vitamin E hastens the healing process of traumatic tympanic membrane perforations.

Animals↗

PubMed2002

Interleukin-8 levels in children with bacterial, tuberculous and aseptic meningitis.

OBJECTIVE: lnterleukin-8 (IL-8) is produced in monocytes and vascular endothelial cells in response to stimulation with bacteria or lipopolysaccharides, and is released from these cells into blood stream or tissue fluid. METHODS: Cerebrospinal fluid (CSF) levels of interleukin-8 in 56 children with nonbacterial, bacterial and tuberculous meningitis (TBM), and in 15 control subjects were analyzed to evaluate the involvement of this cytokine in the pathogenesis acute bacterial meningitis and their discriminative value between different etiologies of meningitis. The kinetics of IL-8 concentrations during the course of bacterial meningitis was also evaluated in patients. IL-8 levels were significantly higher in bacterial and TBM than in aseptic meningitis and in control subjects (p < 0.0001). RESULTS: There was no difference in the levels of IL-8 between the non-bacterial meningitis and control groups. The analysis of the kinetics of production of IL-8 in patients with bacterial meningitis showed that the SSF concentrations of this cytokine decreased to undetectable values in recovery stage. Conversely in patients with TBM the concentrations of IL-8 were elevated in two weeks after beginning the specific treatment. CONCLUSION: The results suggest that determining IL-8 levels may be useful in the differential diagnosis.

Adolescent↗

PubMed2002

The changes of trace elements, malondialdehyde levels and superoxide dismutase activities in pregnancy with or without preeclampsia.

OBJECTIVES: Increased free radical activity and lipid peroxidation may be implicated in the pathogenesis of preeclampsia. This study was initiated to assess antioxidant enzyme and trace metals's status in preeclampsia. DESIGN AND METHODS: The comparison was made between the pregnant women with or without preeclampsia and healthy controls in this study. Samples were obtained from 24 normal nonpregnant (controls), 30 normal pregnant and 21 preeclamptic women in the third trimester. Lipid peroxidation end product, malondialdehyde (MDA), free radical scavenging enzyme activity, superoxide dismutase (SOD) and serum zinc (Zn), copper (Cu) levels were measured in either plasma/serum or erythrocytes of patients. Data were analyzed statistically using Student's t-test. RESULTS: In the preeclamptic group malondialdehyde, Cu levels were significantly increased, while Zn and SOD levels were significantly decreased compared to normal control group and healthy pregnant women. CONCLUSIONS: Our findings give support that radical scavenging SOD is consumed by the increased lipid peroxidation in preeclampsia. This data may indicate an involvement of free radicals in the pathophysiology of preeclampsia. This study suggests a relationship between increased MDA, Cu levels and decreased SOD, Zn levels in pregnancy and preeclampsia.

Adult↗

PubMed2001

Effects of methylprednisolone and dextromethorphan on lipid peroxidation in an experimental model of spinal cord injury.

OBJECTIVE: This study examines the effects of agents purported to improve recovery following spinal cord trauma, methylprednisolone sodium succinate, dextromethorphan, and the combination of both, on the post-traumatic alterations of membrane lipid metabolism. METHODS: After sparing ten rats for a control group (G1) and performing T3-T6 laminectomies in 150 rats, spinal cord injuries were accomplished in 120 of 150 Wistar rats with an aneurysmal clip compression at the level of T4-5 for 30 sec. Hence the G2 group ( n 30) included the "only laminectomy/sham" group. The 120 injured animals were subdivided into four equal groups ( n 30 each). Group G3 underwent no therapy, G4 methylprednisolone (MP), G5 dextromethorphan (DM), and G6 MP+DM therapies. Groups G2-G6 were killed ten by ten at 10 min, 30 min, and 120 min after the operation. We measured tissue (MDA) and blood malonyldialdehyde (MDAb), (a product of lipid peroxidation) levels as an indicator of oxidative damage by thiobarbituric acid method and activity levels of antioxidant enzymes superoxide dismutase and glutathione peroxidase in erythrocytes. Intergroup and intragroup results were compared statistically. RESULTS: Methylprednisolone was able to keep the levels for all parameters close to baseline except for 30-min MDA, MDA(b), and SOD values. But their results were all different from those of G3. Dextromethorphan was successful in this respect at 30-min GSH-Px and 120-min SOD and GSH-Px, and all values were also different from G3 values except for 10-min MDA, SOD, and GSH-Px. Combined therapy was not able to keep levels close to baseline for all parameters, but they were different from G3's except for the GSH-Px values. Methylprednisolone values displayed minimal alterations according to baseline at 120 min. Dextromethorphan was relatively unsuccessful at 10 min. Combined therapy did not show benefit superior to MP/DM single therapies.

Animals↗

PubMedDate not supplied

Apo E gene polymorphism on development of diabetic nephropathy.

Type 2 diabetes causes premature morbidity and mortality due to the complications of atherosclerosis and diabetic nephropathy (DN). Polymorphism of Apo E gene is known to influence lipid metabolism. Apo E is polymorphic, consisting of three common isoforms (epsilon2, epsilon3 and epsilon4) encoded by three alleles (2, 3 and 4) in exon 4 on chromosome 19. The aim of this study was to investigate the effect of Apo E polymorphism as a prognostic risk factor for the development of DN. A total of 108 NIDDM patients were recruited from the Nephrology and Endocrinology Departments of our hospital. All subjects were divided into three groups: Group I: diabetes with nephropathy (n:37), group II: diabetes without nephropathy (n:71), group III: controls (n:46). Apo E genotypes were determined by real-time PCR. The epsilon4 allele frequency was significantly higher in-group I (10.8%) than in-group III (2.2%), (p < 0.05). In diabetics without nephropathy, the total cholesterol and LDL cholesterol levels were significantly lower in subjects with epsilon2 alleles than epsilon3 and epsilon4 alleles. In conclusion, the present prospective study indicates that the epsilon4 allele of the Apo E polymorphism is one of the prognostic risk factors involved in the development of DN with type 2 diabetes mellitus.

Apolipoproteins E↗

PubMedDate not supplied

Variable effects of exercise intensity on reduced glutathione, thiobarbituric acid reactive substance levels, and glucose concentration.

BACKGROUND: Physical exercise may be associated with a 10- to 20-fold increase in whole body oxygen uptake. Generation of free oxygen radicals (FORs) is elevated to a level that overwhelms tissue antioxidant defense systems in exercise. One of the most reliable indices of exercise-induced oxidant production is tissue glutathione oxidation. METHODS: In this study three different volunteer groups carried out various sports disciplines and worked at least as amateurs for 6-7 years before and after aerobic (Aer)-, anaerobic (Anae)-, or aerobic + anaerobic (Aer-Anae)-dominant exercises. Thiobarbituric acid reactive substances (TBARS) reduced glutathione (GSH) levels, glucose concentration was measured, and we investigated their relationships with different types of exercise. From all groups (n=60, each group comprising 10 females and 10 males), we collected blood samples at the following five different times: before exercise; immediately after exercise, and 4, 24, and 48 h after completion of exercise. These samples were assayed for whole blood GSH, plasma TBARS levels, and glucose concentration. RESULTS: Significant increase in Aer-Anae was noted in levels of TBARS while decrease was observed in glutathione levels in exercise group as compared with prior levels in all groups. However, no statistical difference was observed in total group levels before and after exercise and in male and female groups compared before and after exercise. When gender differences were taken into account, females generally had higher levels of GSH, whereas TBARS levels were higher in males. When compared either before or after exercise, levels of glucose concentration--especially immediately after exercise period in all groups--were higher. In addition, in Anae groups glucose concentrations were higher at 4 and 24 h in females than in males. Aer exercise caused oxidative stress to a lesser degree, whereas Aer-Anae exercise caused oxidative stress of higher degree that was statistically significant. CONCLUSIONS: According to our findings, exercise increased TBARS level significantly in all groups, especially more so in Aer-Anae groups. In addition, GSH was increased more in females than in males, while concentration of glucose did not change remarkably. Additionally, it can be stated that women are more resistant to oxidative stress.

Adult↗

PubMedDate not supplied

Antioxidant vitamin levels in term and preterm infants and their relation to maternal vitamin status.

BACKGROUND: Lipid peroxidation plays a vital role in the pathogenesis of many neonatal complications. Preterm babies are especially predisposed to lung diseases and retinopathy, probably due to a deficiency in their antioxidant systems. Vitamins E, A, and C are part of the natural antioxidant defense systems. We aimed to determine the levels of vitamins E, A, and C in maternal and cord blood plasma of term and preterm infants and to investigate the relationships between these levels. METHODS: In the present study we determined vitamin E, A, and C levels in the umbilical cord blood of term (n = 30) and preterm (n = 22) infants and their mothers by HPLC. Blood samples were taken during delivery. RESULTS: Levels of lipid soluble antioxidant vitamin E and A in cord blood were lower than maternal values (p <0.01, p <0.05, respectively). Conversely, the level of water-soluble vitamin C was higher in cord blood than in maternal level (p <0.05). Significantly higher levels of vitamins E, A, and C were found in term babies as compared with those born preterm (p <0.05). CONCLUSIONS: There was a positive correlation between maternal and cord blood levels of vitamins E and A (r = 0.775, r = 0.725, respectively). In conclusion, preterm babies have fewer lipid-soluble antioxidant vitamins in their serum compared to term infants. Therefore, it is possible to postulate that preterm infants are more susceptible to oxidative stress.

Antioxidants↗

PubMedDate not supplied

L-carnitine in experimental retinal ischemia-reperfusion injury.

The effect of L-carnitine on retinal ischemia-reperfusion injury was evaluated in guinea pigs. 90 min of pressure-induced retinal ischemia followed by 24 h of reperfusion was established in both eyes of 2 groups of animals receiving either L-carnitine (100 mg/kg repeated in 5 doses) or saline intraperitoneally. After enucleation of all the eyes, including those of a control group, malonyldialdehyde (MDA) levels and the thickness of the retinal tissue were measured in 3 groups. The mean MDA value and the tissue thickness of the L-carnitine-treated group were statistically insignificant versus the control group (p > 0.05 and p > 0.05, respectively). However, these values were significantly different in the group receiving saline versus the control group and that receiving L-carnitine (p < 0.001, p < 0.001 and p < 0.001, p < 0.001 respectively). L-Carnitine might be an alternative drug for ischemia-reperfusion injury of the retina.

Animals↗

PubMedDate not supplied

Protective effects of pentoxifylline in retinal ischemia/reperfusion injury.

We studied the effect of pentoxifylline on retinal lipid peroxidation and histopathologic changes due to ischemia/reperfusion (I/R). A total of 15 pigmented male guinea pigs were divided into 3 equal groups as control, sham and treatment groups. After application of high intraocular pressure for 90 min for the induction of retinal ischemia, 24-hour reperfusion was established in the sham and treatment groups. In the treatment and sham groups, either 45 mg/kg of pentoxifylline or saline was given 3 times at 8-hour intervals. Biochemical assay and histopathologic evaluation were performed on one randomly selected eye of each animal which was enucleated at the end of the reperfusion period, and retinal malondialdehyde (MDA) levels and thickness of the retinal tissue were determined for each group. The mean MDA level of the sham group was significantly higher versus the control and treatment groups (p < 0.001). When compared with the control group, the mean MDA level of the treatment group was slightly higher, but the difference was not statistically significant (p > 0.05). In comparison with the control group there was a significant increase in the thickness of the retina in the sham group (p < 0.0001), and no significant difference was found in the retinal thickness of the treatment group (p > 0.05). Pentoxifylline might have a preventive effect on the I/R injury of the retina.

Animals↗

PubMedDate not supplied

The protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation.

PURPOSE: The purpose of this study was to determine the protective effect of alpha-lipoic acid against oxidative damage in rabbit conjunctiva and cornea exposed to ultraviolet radiation. METHODS: 20 rabbits weighing 2,500- 3,000 g were used, and we divided them into 4 groups with 5 randomly selected rabbits. The rabbits were exposed to 2 J/cm(2)/h of ultraviolet A radiation (UVA) in the range of 320-405 nm for 12 h per day within 90 days. The control group did not undergo any procedure, the UVA group was only exposed to UVA radiation. The PUVA group was treated with 8-methoxypsoralen and UVA. The alpha-lipoic acid group was administered 8-methoxypsoralen + UVA + alpha-lipoic acid. At the end of 90 days, the rabbits were killed by decapitation, and the eyes were enucleated. Both eyes of each rabbit were used for biochemical evaluation. Conjunctival and corneal free malondialdehyde (MDA), glutathione peroxidase (GSH-PX) and superoxide dismutase (SOD) levels were compared among the groups. RESULTS: Conjunctival free MDA levels were lower in the alpha-lipoic acid group compared with the UVA and PUVA groups (p < 0.05, p < 0.001, respectively). Both conjunctival SOD levels (p < 0.05, p < 0.01, respectively) and conjunctival GSH-PX levels (p < 0.01, p < 0.001, respectively) were higher in the alpha-lipoic acid group compared with other groups. Corneal free MDA levels were lower in the alpha-lipoic acid group compared with the UVA and PUVA groups (p < 0.01, p < 0.001, respectively). Both corneal SOD levels (p < 0.01, p < 0.01, respectively) and corneal GSH-PX levels (p < 0.01, p < 0.01, respectively) were higher in the alpha-lipoic acid group compared with the other groups. CONCLUSION: alpha-Lipoic acid which is considered as potent antioxidant protects the eye from the damaging effect of ultraviolet exposure.

Animals↗

PubMedDate not supplied

Protective effect of interferon-alpha on carbon tetrachloride-induced nephrotoxicity.

BACKGROUND: The aim of this study was to investigate the effect of chronic administration of interferon-alpha 2b for the prevention of carbon tetrachloride (CCl4)-induced oxidative stress and nephrotoxicity. METHODS: Thirty rats were divided into three groups: control, CCl4+placebo (CCl4+P) and CCl4+interferon-alpha 2b (CCl4+INF). Control rats were treated with pure olive oil. The other rats were treated for seven weeks with subcutaneous injections of CCl4 (0.15 mL /kg) in pure olive oil three times a week. Rats were killed at the end of the seventh week and renal histopathological examinations were done: specimens of renal tissue were obtained for investigating oxidative stress parameters, including malondialdehyde (MDA) and glutathione peroxidase (GSH-Px). RESULTS: Tubular changes, glomerular hypercellularity, and capillary obliteration were significantly less in the CCl4+INF group than with CCl4+P (p<0.05) and the interstitial fibrosis score for the CCl4+INF group was similar to the control group. However, the interstitial inflammation score was higher in the CCl4+INF group than the control group (p<0.05). No change was observed in the CCl4+P group. Renal MDA levels in the control and CCl4+INF groups were significantly lower than the CCl4+P group, while GSH-Px was significantly higher (p<0.001). There was no difference between the control and CCl4+INF groups in oxidative stress markers (p>0.05). CONCLUSIONS: Administration of interferon-alpha 2b to CCl4-treated rats prevented interstitial fibrosis, probably as a result of its antifibrogenic effect. It also reduced intrarenal oxidative stress in rats with CCl4-induced nephrotoxicity.

Analysis of Variance↗