Thioredoxin System and miR-21, miR-23a/b and let-7a as Potential Biomarkers for Brain Tumor Progression: Preliminary Case Data.

BACKGROUND: The thioredoxin system and microRNAs (miRNAs) are potential targets for both cancer progression and treatment. However, the role of miRNAs and their relation with the expression profile of thioredoxin system in brain tumor progression remains unclear. METHODS: In this study, we aimed to determine the expression profiles of redox components Trx-1, TrxR-1 and PRDX-1, and oncogenic miR-21, miR-23a/b and let-7a and oncosuppressor miR-125 in different brain tumor tissues and their association with increasing tumor grade. We studied Trx-1, TrxR-1, and PRDX-1 messenger RNA expression levels by quantitative real-time polymerase chain reaction and protein levels by Western blot and miR-23a, miR-23b, miR-125a, miR-21, and let-7a miRNA expression levels by quantitative real-time polymerase chain reaction in 16 glioma, 15 meningioma, 5 metastatic, and 2 benign tumor samples. We also examined Trx-1, TrxR-1, and PRDX-1 protein levels in serum samples of 36 patients with brain tumor and 37 healthy volunteers by enzyme-linked immunosorbent assay. RESULTS: We found that Trx-1, TrxR-1, and PRDX-1 presented high messenger RNA expression but low protein expression in low-grade brain tumor tissues, whereas they showed higher protein expression in sera of patients with low-grade brain tumors. miR-23b, miR-21, miR-23a, and let-7a were highly expressed in low-grade brain tumor tissues and positively correlated with the increase in thioredoxin system activity. CONCLUSIONS: Our findings showed that Trx-1, TrxR-1, miR-21, miR-23a/b, and let-7a might be used for brain tumor diagnosis in the clinic. Further prospective studies including molecular pathway analyses are required to validate the miRNA/Trx system regulatory axis in brain tumor progression.

Endothelial dysfunction and insulin resistance in young women with polycystic ovarian syndrome.

BACKGROUND/AIM: To evaluate whether there is a correlation between insulin resistance and nitric oxide-related endothelial dysfunction in patients with polycystic ovarian syndrome (PCOS). MATERIALS AND METHODS: The study was conducted with 25 young women with PCOS and 25 young healthy women, between 18 and 35 years of age. Plasma asymmetric dimethylarginine (ADMA) levels, serum nitric oxide (NO) levels, and homeostatic model assessment of insulin resistance (HOMA-IR) rates were measured in both the patient and control groups. RESULTS: Plasma ADMA levels were significantly higher in PCOS patients than in the controls (P = 0.001). Serum NO levels were significantly lower in patients than in the controls (P = 0.008). The HOMA-IR rates, accepted as an insulin resistance parameter, were significantly higher in patients than in the controls (P = 0.001). CONCLUSION: Results of the present study indicate that, independent of age, body mass index, and blood lipid profile, there is significant insulin resistance in PCOS patients. However, no correlation was found between HOMA-IR as an insulin resistance determinant and altered ADMA and NO levels. This finding may indicate that there are additional mechanisms of cardiovascular risks in PCOS patients other than insulin resistance.

An investigation into the serum thioredoxin, superoxide dismutase, malondialdehyde, and advanced oxidation protein products in patients with breast cancer.

BACKGROUND: Reactive oxygen species (free radicals) play an important role in carcinogenesis. Extensive antioxidant defense mechanisms counteract free radicals in mammalian cells. Oxidative stress is a disturbance in the balance between the production of free radicals and antioxidant defenses. There is direct evidence that oxidative stress and lipid peroxidation (LPO) are linked to the etiology of breast cancer. The increasing global incidence of breast cancer emphasizes the need to understand the various mechanisms involved in breast tumorigenesis. The present study was undertaken to investigate the oxidative stress and antioxidant status in the blood samples of patients with breast cancer. METHODS: The present study was based on 23 women who were surgically treated at Gazi University, Faculty of Medicine, Department of General Surgery. The malondialdehyde (MDA) levels as an index of LPO along with the examination of superoxide dismutase (SOD) activities and advanced oxidation protein product (AOPP) and thioredoxin (Trx) levels were determined in the blood samples of 23 patients with breast cancer and 13 healthy controls. RESULTS: MDA, AOPP, and Trx levels and SOD activities were significantly higher in patients with breast cancer than the controls. CONCLUSIONS: The results showed that oxidative stress may be related to breast cancer and especially some molecules, such as Trx and AOPP, may be useful biomarkers in breast cancer diagnosis and treatment. More detailed knowledge related to the pathophysiology of these molecules could provide valuable information on the origin and development of malignant tumors, such as breast cancer.

Neuroprotective effects of gabapentin on spinal cord ischemia-reperfusion injury in rabbits.

OBJECT: Extensive research has been focused on neuroprotection after spinal cord trauma to alleviate the effects of secondary injury. This study aims to investigate the neuroprotective effects of gabapentin in an experimental spinal cord ischemia reperfusion injury. METHODS: Thirty-two adult male New Zealand white rabbits received spinal cord ischemic injury using the aortic occlusion model. Animals were divided into 4 groups (sham, control, low-dose, and high-dose treatment groups; 8 rabbits in each group). High (200 mg/kg) and low (30 mg/kg) doses of gabapentin were administered to the animals in the treatment groups after spinal cord ischemic injury. Neurological status of the animals, ultrastructural findings in injured tissue samples, and levels of tissue injury markers in these 2 groups were compared with findings in the animals that did not receive the ischemic procedure (sham-operated group) and those that received normal saline after administration of ischemia. RESULTS: Regarding levels of tissue injury marker levels after ischemic injury, animals in the gabapentin-treated groups demonstrated better results than animals in the other groups. The ultrastructural findings and caspase-3 activity were similar. The treatment groups demonstrated better results than the other groups. CONCLUSIONS: Gabapentin demonstrated significant neuroprotection after early phases of ischemic injury. Further studies with different experimental settings including neurological outcome are required to achieve conclusive results.

Fluorometric determination of acid proteinase activity in Candida albicans strains from diabetic patients with vulvovaginal candidiasis.

Vulvovaginal candidiasis is one of the most frequent disorders in obstetrics and gynaecology. Approximately three-quarters of all adult women experience at least one episode of vulvovaginal candidiasis during their life span. Diabetes mellitus (DM) increases the rate of vaginal colonisation and infection with Candida species. The secreted acid proteinase might be especially relevant in the pathogenesis of vulvovaginal candidiasis. The aim of this study was to determine the acid proteinase activity in the samples of Candida albicans from diabetic patients with vulvovaginal candidiasis by a fluorometric method. Vaginal swabs were taken from 33 women (aged between 22 and 57 years) having symptoms of vaginitis. Patients were divided into three groups: control group, controlled diabetic group and uncontrolled diabetic group. The proteinase activity in the culture supernatants was determined by a modified fluorometric method. Acid proteinase activities were significantly increased in the uncontrolled diabetic group in comparison with both the control group and the controlled diabetic group (P < 0.05). Acid proteinase may play an important role in C. albicans pathogenesis in diabetic patients. Improving glucose control may reduce the risk of Candida colonisation and potentially symptomatic infection, among women with diabetes and hence may be useful even for weaker enzyme activity measurements.

Neuroprotective effects of infliximab in experimental spinal cord ischemic injury.

Reactive oxygen species (ROS) have been implicated in the pathogenesis of spinal cord injury after both ischemia-reperfusion (I/R) and trauma. This experimental study was designed to investigate the potential effects of infliximab, an anti-tumor necrosis factor-α agent, on I/R injury of the rabbit spinal cord. Eighteen New Zealand white rabbits were divided into three groups, each consisting of six rabbits: sham (no I/R), I/R, and infliximab (I/R + infliximab). Spinal cord ischemia was induced by applying an infrarenal aortic cross clamp for 30 minutes. At 48 hours after ischemia, animals were functionally evaluated using the Tarlov score. Changes in the spinal cord were observed by measuring tissue levels of malondialdehyde (MDA), glutathione (GSH), advanced oxidation protein products (AOPP), and superoxide dismutase (SOD) and by evaluating hematoxylin-eosin-stained sections. At 48 hours after ischemia, the Tarlov scores in the infliximab group were higher than those of the I/R group, MDA and AOPP levels in the I/R group were significantly higher than those in the sham and infliximab groups (p < 0.05), and SOD levels in the infliximab group were significantly higher than those in the I/R and sham groups (p < 0.05). The sham group had higher GSH levels than the infliximab group; however, the difference was not statistically significant (p > 0.05). Histological examination revealed that the infliximab group had significantly less vascular proliferation, edema, and neuron loss than the I/R group. These results indicate that infliximab may protect the spinal cord against injury in a rabbit I/R model.

Anti-apoptotic and neuroprotective effects of α-lipoic acid on spinal cord ischemia-reperfusion injury in rabbits.

PURPOSE: Radical oxygen species produced after injury counteracts antioxidant activity and frequently causes severe oxidative stress for the tissues. Alpha-lipoic acid is a powerful metabolic antioxidant with immunomodulatory effects which provides neuroprotection. The aim of this study is to investigate the neuroprotective and anti-apoptotic effects of alpha-lipoic acid on spinal cord ischemia-reperfusion. METHODS: Twenty-four adult, male, New Zealand rabbits were divided into sham (n = 8), control (n = 8), and treatment groups (n = 8). The abdominal aorta was clamped for 30 min by an aneurysm clip, approximately 1 cm below the renal artery and 1 cm above the iliac bifurcation in control and treatment groups. Only laparotomy was performed in the sham group. Twenty-five cubic centimeters of saline in control group and 100 mg/kg lipoic acid were administered intraperitoneally in the treatment group after closure of the incision. The animals were killed 48 h later. Spinal cord segments between L2 and S1 were harvested for analysis. Levels of nitric oxide, glutathione, malondialdehyde, advanced oxidation protein products, and superoxide dismutase were analyzed as markers of oxidative stress and inflammation. Caspase-3 activity was analyzed to detect the effect of lipoic acid on apoptosis. RESULTS: In all measured parameters of oxidative stress, administration of lipoic acid significantly demonstrated favorable effects. Both plasma and tissue levels of nitric oxide, glutathione, malondialdehyde, and advanced oxidation protein products significantly changed in favor of antioxidant activity. There was no significant difference between the plasma superoxide dismutase levels of the groups. Histopathological evaluation of the tissues also demonstrated significant decrease in cellular degeneration and infiltration parameters after lipoic acid administration. However, lipoic acid has no effect on caspase-3 activity. CONCLUSIONS: Although further studies considering different dose regimens and time intervals are required, the results of the present study prove that alpha-lipoic acid has favorable effects on experimental spinal cord ischemia-reperfusion injury.

Identification of salivary mucin MUC7 binding proteins from Streptococcus gordonii.

BACKGROUND: The salivary mucin MUC7 (previously known as MG2) can adhere to various strains of streptococci that are primary colonizers and predominant microorganisms of the oral cavity. Although there is a growing interest in interaction between oral pathogens and salivary mucins, studies reporting the specific binding sites on the bacteria are rather limited. Identification and characterization of the specific interacting proteins on the bacterial cell surface, termed adhesins, are crucial to further understand host-pathogen interactions. RESULTS: We demonstrate here, using purified MUC7 to overlay blots of SDS-extracts of Streptococcus gordonii cell surface proteins, 4 MUC7-binding bands, with apparent molecular masses of 62, 78, 84 and 133 kDa from the Streptococcus gordonii strain, PK488. Putative adhesins were identified by in-gel digestion and subsequent nanoLC-tandem mass spectrometry analysis of resultant peptides. The 62 kDa and 84 kDa bands were identified as elongation factor (EF) Tu and EF-G respectively. The 78 kDa band was a hppA gene product; the 74 kDa oligopeptide-binding lipoprotein. The 133 kDa band contained two proteins; alpha enolase and DNA-directed RNA polymerase, beta' subunit. Some of these proteins, for example alpha enolase are expected to be intracellular, however, flow cytometric analysis confirmed its location on the bacterial surface. CONCLUSION: Our data demonstrated that S. gordonii expressed a number of putative MUC7 recognizing proteins and these contribute to MUC7 mucin binding of this streptococcal strain.

The evaluation of the oxidative stress parameters in nondiabetic and diabetic senile cataract patients.

The aim of the present study was to evaluate the copper (Cu), zinc (Zn), malondialdehyde (MDA), glutathione (GSH), and advanced oxidation protein products (AOPP) levels and superoxide dismutase (SOD) activities in diabetic senile cataract. Ten patients with diabetic senile cataract and ten patients with nondiabetic senile cataract (control group) were included in this study. AOPP, MDA, and GSH levels and SOD activity were measured by a spectrophotometric method. Serum, lens Cu, and Zn levels were measured by an atomic absorption spectrophotometric method. Both the lens and serum Zn and Cu levels between the two groups were not significantly different (p > 0.05). GSH, AOPP, and MDA levels and the SOD activities in the diabetic senile cataract group were significantly increased as compared to the control group (p < 0.05). Oxidative stress is one of the major factors which may lead to the early cataract formation. Oxidative events are of great importance in diabetic complications and, particularly in the lens, may have a role in the pathogenesis of cataract associated with diabetes mellitus as exhibited in this study.

The mechanism of the late preconditioning effect of 3-nitropropionic acid.

The aim of the present study was to investigate the mechanism of effect of 3-nitropropionic acid-(3-NP) induced late preconditioning in rat heart. For this purpose 20-30 min before 3-NP (20 mg/kg, i.p.) injection, the rats were treated intraperitoneally with 5-hydroxydecanoate (40 mg/kg, 5-HD, mitochondrial K(ATP)-channel blocker), L-NAME (100 mg/kg, NOS inhibitor), N-2-mercaptopropionylglycine (100 mg/kg, MPG, free radical scavenger), or superoxide dismutase+catalase (10000+10000 IU/kg, SOD+CAT). Control rats received saline only without 3-NP pretreatment. After two days, hearts were isolated and perfused at a constant pressure in a Langendorff apparatus. 15-min global ischemia followed by 30-min reperfusion was applied to all hearts. Pretreatment of 3-NP significantly reduced infarct size, creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH) levels, and incidence of ventricular tachycardia (VT) compared with the control group receiving saline only. 5-HD, L-NAME, MPG, or SOD+CAT treatment statistically reversed 3-NP-induced reduction in infarct size. Although CK-MB, LDH levels, and incidence of VT were also reduced by L-NAME, MPG, or SOD+CAT treatment, only 5-HD significantly inhibited beneficial effects of 3-NP on all of the parameters above. These results showed that mito-K(ATP) channels play a pivotal role in late preconditioning effect of 3-NP in the isolated rat heart. However, other mediators such as reactive oxygen species and NO may be, at least in part, involved in mechanisms of this effect.

Antioxidant enzymes and diabetic retinopathy.

The aim of this study was to discuss the serum copper (Cu), zinc (Zn), nitric oxide (NO), glutathione (GSH), advanced oxidation protein products (AOPP) levels, and superoxide dismutase (SOD) activities with diabetic retinopathy severity. Twenty-five patients with proliferative diabetic retinopathy (PDR group 1), 25 patients with nonproliferative diabetic retinopathy (NPDR group 2), and 25 nondiabetic controls (control group) were included in the study. Patients who had macrovascular complications of diabetes (coronary arterial disease, periferic vascular disease) were excluded. The major finding of our study was that we did not observe any differences between group 1 and 2, which we aimed to discuss the severity of diabetic retinopathy. As the levels of SOD and Zn were not different between the groups, statistically significant differences were observed for GSH, NO, and Cu levels when compared to control group. AOPP levels were statistically increased in group 1 compared to control group. It can be suggested that hyperglycemia in DM is associated with accelerated nonenzymatic glycation and oxidative stress.

Pseudoexfoliation syndrome and trace elements.

To investigate the role of zinc and copper in the development of pseudoexfoliation (PSX) syndrome, 34 cataract patients with PSX syndrome and 27 cataract patients without PSX syndrome were included in the study and groups were matched for age and gender. During the cataract surgery, lenses were obtained intraoperatively, frozen under liquid nitrogen, and kept at -70 degrees C until processing. Zinc and copper concentrations were measured by atomic absorption spectrophotometric method after the homogenization (acid hydrolysis) of dried lenses. The mean concentration of zinc in the lens from patients with PSX (20.33 +/- 8.76 microg/g tissue; range 11.04-42.94 microg/g tissue) was significantly lower than that measured in the lens of patients without PSX (28.88 +/- 15.32 microg/g tissue; range 12.02-64.32 microg/g tissue) (P < 0.05). The mean concentration of copper in the lens from patients with PSX (29.51 +/- 10.05 microg/g tissue; range 12.69-59.71 microg/g tissue) and in the lens of patients without PSX (39.72 +/- 25.64 microg/g tissue; range 12.38-92.14 microg/g tissue) was not statistically different. The decreased content of zinc could increase oxidative stress. The results support the role of oxidative stress in the development of PSX in cataract patients.

The importance of serum lipids in exudative diabetic macular edema in type 2 diabetic patients.

To evaluate the relationship between serum lipid levels and exudative diabetic maculopathy in patients with nonproliferative diabetic retinopathy, 27 patients with exudative diabetic macular edema were included in group A and 27 patients without exudative diabetic macular edema were included in group B. All 54 patients have nonproliferative diabetic retinopathy. Blood cholesterol, triglyceride, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, very low-density lipoprotein (VLDL) cholesterol, hemoglobin A1c (HbA1c), and hemoglobin levels were measured in patients in group A and group B. The mean concentration of cholesterol in group A (224.30 +/- 49.49 mg/dL), in group B (197.78 +/- 41.49 mg/dL); triglyceride in group A (199.11 +/- 90.51 mg/dL), in group B (160.78 +/- 65.30 mg/dL); HDL in group A (43.48 +/- 10.62 mmol/L), in group B (42.37 +/- 10.92 mmol/L); LDL in group A (150.59 +/- 43.96 mg/dL), in group B (124.37 +/- 40.28 mg/dL); VLDL in group A (40.52 +/- 16.54 mg/dL), in group B (37.89 +/- 23.70 mg/dL); HbA1c in group A (9.62 +/- 2.50), in group B (7.36 +/- 1.62 g/dL); and hemoglobin in group A (13.46 +/- 1.6 g/dL), in group B (13.90 +/- 1.77 g/dL). Serum cholesterol (P = 0.38), LDL (P = 0.026), and HbA1c (P = 0.000) levels were different between the two groups. Triglyceride, HDL, VLDL, and hemoglobin levels were not different between the two groups. We must consider regulation of high blood sugar and elevated total serum cholesterol or LDL levels in patients with macular edema and high hard exudates.

Effects of taurine in cellular responses to oxidative stress in young and middle-aged rat liver.

Aging is related with an increased cellular level of lipid peroxides and reactive oxygen species (ROS). The useful effects of taurine as an antioxidant in biological systems have been attributed to its capability to stabilize biomembranes, to scavenge ROS, and to decrease the peroxidation of unsaturated membrane lipids. The aim of the present study was to investigate the effects of taurine on malondialdehyde (MDA), glutathione (GSH), glutathione peroxidase (GPx), thioredoxin reductase (TR), and endothelial nitric oxide synthase (eNOS) in young and middle-aged rat liver. There was not a significant difference in liver MDA levels between the control groups of young and middle-aged rats (P > 0.05). However, liver GSH levels, and GPx and TR activities between the control groups of young and middle-aged rats were significantly different (P < 0.05). Liver MDA level was significantly lower in the taurine group of middle-aged rats (P < 0.05). Liver GSH levels, and GPx and TR activities were significantly increased in the taurine group of middle-aged rats when compared to the control group (P < 0.05). Liver MDA level was significantly lower in the taurine group of young rats than the ones in the control group (P < 0.05). Liver TR activity was significantly increased in the taurine group of young rats when compared to the control group (P < 0.05). Liver GPx activity was not statistically different between the taurine and the control groups in young rats (P > 0.05). Liver GSH levels were not different between the young taurine and the control groups (P > 0.05). Immunohistochemical studies exhibited no change in eNOS activity after taurine injection in young rats. However, in middle-aged rats, taurine lowered the eNOS reactivity to the same level found in young rats. These results suggested that exogenous taurine might play a role in aging by means of its reducing effects on free radical levels in parallel to an increase in the antioxidant capacity.

The effect of time of day and exercise on platelet functions and platelet-neutrophil aggregates in healthy male subjects.

Platelet activation state changes by exercise. The effect of exercise time on platelet activation state and formation of platelet-neutrophil aggregates are not known yet. In this study the effect of exercise and time of day were examined on platelet activity with platelet-neutrophil aggregates. Ten moderately active males aged 27+/- 1.63 (mean+/-S.D.) years completed sub-maximal (70% VO(2max)) exercise trials for 30 min. Blood pressure (BP) was recorded. Venous blood samples were obtained at rest, immediately post-exercise and after 30 min of recovery. Whole blood was analysed for haematocrit (Hct), haemoglobin (Hb), platelet count (PC), mean platelet count (MPV) and platelet aggregation (PA). Platelet-neutrophil aggregates and beta-thromboglobulin (beta-TG) levels were assayed. Platelet count showed significant increase after morning exercise ((236+/- 32)x10(9) l(-1) versus (202+/- 34)x10(9) l(-1) baseline, p < 0.05). Exercise resulted in significantly lower MPV after the evening exercise (9.16+/- 0.5 fl versus 9.65+/- 0.36 fl, p < 0.05). Platelet aggregation by adenosine diphosphate (ADP) decreased after morning exercise and the recovery aggregation levels were significantly different at two different times of the day (68+/- 20% a.m. versus 80+/- 12% p.m., p < 0.05). It was also showed that platelet-neutrophil aggregates increased significantly from baseline after both exercises. Exercise-induced platelet-neutrophil aggregates were higher in the evening (10.7+/- 1.3% p.m. versus 6.4+/- 1.8% a.m., p < 0.0001). It is therefore concluded that besides platelet-platelet aggregation, exercise can cause platelet- neutrophil aggregates. In addition, time of day has an effect on platelet activation related events. Circadian variations of physiological parameters may have an effect on thrombus formation by platelet activation.