Respiratory viruses: What is their role in acute exacerbations in children with cystic fibrosis?

BACKGROUND: Respiratory viruses (RVs) are frequently present in the airways of patients with cystic fibrosis (CF) during pulmonary exacerbations (PEx). METHOD AND OBJECTIVES: This prospective, longitudinal study was performed to examine the role of RVs in acute exacerbations in children with CF. Sputum samples or additional midturbinate swabs were tested from all children using a polymerase chain reaction panel. The primary aims of the study were to determine the prevalence and etiologic role of RVs in exacerbations of CF and to compare changes with RV-positive and RV-negative infections. The secondary aims were to determine the predictive factors for RV-related exacerbations. RESULTS: From 50 patients with PEx, 23 (48.9%) sputum samples were virus-positive. With a combination of sputum and swab, viral positivity increased to 56%. The virus-positive group presented more frequently with hypoxia (oxygen saturation <93%) than the virus-negative group (P = .048). Virus-positive exacerbations were not associated with an increase in colonization rates or greater lung function decline over 12 months. CONCLUSIONS: RVs frequently present during PEx of CF. However, predicting viral infections is difficult in this group. Only the presence of hypoxia may raise the suspicion of an accompanying viral agent. The combination of sputum and nasal swab samples increases the diagnostic yield in viral infections of CF. Despite their high frequency, the presence of RVs had no impact on clinical outcomes, such as a decline in lung function and increased colonization rates.

Glass-ceramics bonding in geriatric patients: comparison with young teeth.

OBJECTIVE: The aim of the study was to assess whether in geriatric patients, the shear bond strength (SBS) of glass-ceramics differed when compared to young controls. BACKGROUND: In the need of aesthetic restorations for geriatric patients, reliable bonding of glass-ceramics should be accomplished; however, glass-ceramics bonding on aged tooth structures is still unclear. MATERIALS AND METHODS: Sixty extracted molars from young and geriatric patients [18-25 (Y), and 65-80 (O)] were cut buccolingually to prepare enamel (E) and dentin (D) surfaces. Both surfaces were randomly divided into three groups according to the resin cements: Variolink II (V); Superbond (S); and Clearfil Esthetic Cement (C) (n = 10). Disc-shaped glass-ceramics (IPS E-max Press) (n = 120) were prepared. Specimens were bonded and subjected to thermocycling. SBS test was performed using a universal testing machine (0.5 mm/min). After debonding, the surfaces were examined using stereomicroscope and scanning electron microscope. Data were statistically analysed with Kolmogorov-Smirnov, Levene, anova and Bonferroni tests (p = 0.05). RESULTS: There were no significant differences between the old and young teeth surfaces. V showed the highest SBS [MPa(SD)] on both enamel and dentin [36.7 (6.5) (YE), 23.2 (13.2) (YD), 32.1 (16.2) (OE), 25.5 (8.6) (OD), respectively]. Significant differences were observed between resin cements (p < 0.05). The failure types were 43% adhesive between tooth and cement, 48% mix, 9% adhesive between cement and ceramic, regardless of cement type. CONCLUSION: In geriatric patients, the shear bond strength of glass-ceramics did not differ when compared to that of young controls. On the dentin surface, etch-rinse resin cements appear to be more appropriate for glass-ceramics bonding.

Effect of clopidogrel on nitric oxide levels in an ischemia reperfusion model.

Ischemia and reperfusion injury is a pathologic process with serious consequences, arising due to interruption of arterial blood flow. Restored blood flow achieved after the ischemic period causes formation of oxygen radicals by activation of a variety of substances and systems. In this study, we investigated the effect of clopidogrel, an antithrombocyte agent, on tissue nitric oxide (NO) levels in an experimental ischemia reperfusion model. For this purpose, 6 hours of ischemia and 4 hours of subsequent reperfusion were applied to the right lower extremities of the subjects. Clopidogrel therapy was started in one of these groups 10 days before the process (study group). NO levels were measured in all groups in the muscle, lung, and liver tissues, and in plasma. Lung, plasma, and liver NO measurement values had statistically significant differences among the groups. There was no statistically significant difference in the measurements made on the muscle tissue. Clopidogrel, which has previously been reported to be suitable to be used as a preventive agent of ischemia reperfusion damage, has had a reducing effect on the NO levels in tissues in the ischemia reperfusion model created in our present study.

Malondialdehyde, glutathione, glutathione peroxidase and homocysteine levels in type 2 diabetic patients with and without microalbuminuria.

BACKGROUND: High levels of homocysteine and oxidative stress are known to be associated with premature vascular disease in type 2 diabetes mellitus (DM). The aim of this study was to estimate homocysteine levels and oxidant-antioxidant status and to determine the relationship between them in type 2 diabetic patients with and without microalbuminuria. METHODS: Fasting blood samples were obtained from 48 diabetic patients (17 with and 31 without microalbuminuria) and 20 healthy subjects. Serum total homocysteine (tHcy), plasma malondialdehyde (MDA) erythrocyte glutathione (GSH) and glutathione peroxidase (GPx) activity were measured in these patients and the results were compared with those of controls who were chosen among healthy subjects. RESULTS: MDA levels were found to be significantly lower and GSH levels and GPx activities were found to be significantly higher in control subjects when compared with patients with and without microalbuminuria (MDA: P < 0.0001, P < 0.0001; GSH: P < 0.0001, P < 0.0001; GPx: P < 0.0001, P < 0.001, respectively). MDA levels were found to be significantly higher in patients with microalbuminuria compared with patients without microalbuminuria (P < 0.0001), while similarly GSH levels were found to be significantly lower in patients with microalbuminuria (P < 0.0001). Although there were no significant differences with respect to tHcy levels and GPx activities between the microalbuminuric and normoalbuminuric patients (P > 0.05), there was a significant difference with respect to tHcy levels between healthy controls and patients with microalbuminuria (P < 0.05). The serum levels of tHcy correlated best with plasma MDA and erythrocyte GSH concentrations in all diabetic patients (r = 0.549, P < 0.0001; r = -0.385, P<0.01). CONCLUSION: Decreased antioxidant levels, increased lipid peroxidation and increased tHcy levels were observed in patients with microalbuminuria. These changes may contribute to vascular disease, which is particularly prevalent in type 2 DM patients with microalbuminuria.

Protective effects of clopidogrel on oxidant damage in a rat model of acute ischemia.

Reperfusion injury is a consequence of inadequate energy supply and acidosis in ischemic tissues and a chain of events triggered by oxygen-derived free radicals released in response to exposure of oxygen. In this study, we aimed to assess the effects of clopidogrel, an antithrombotic agent, on experimental ischemia-reperfusion model in rats. The ischemia was performed by blockade of the circulation of right lower extremity at trochanter major level for 6 hours. Then, the extremity was reperfused for 4 hours. Another group of rats pretreated with clopidogrel (0.2 mg/kg/day) for 10 days prior to ischemia-reperfusion. After the reperfusion period, all rats were anesthetized with ketamine. Blood and tissue samples from the gastrocnemius muscle, liver and lungs were taken for the measurement of malondialdehyde (MDA), glutathione (GSH) levels and superoxide dismutase (SOD) activity. The results revealed that clopidogrel prevented the increase in MDA level and the decrease in GSH level and SOD activity caused by ischemia-reperfusion both in tissue samples and plasma. These findings suggest that clopidogrel is beneficial in prevention of ischemia-reperfusion injury probably via its effects on inflammatory cells, platelets, and endothelial cells.

The effects of thinner inhalation on superoxide dismutase activities, malondialdehyde and glutathione levels in rat lungs.

BACKGROUND: Recent years' usage of thinner by the young generation as a drug constitutes a serious problem in the society. Due to common usage in the industrial sector, most people are affected from the manufacturing process to the consuming phase. AIM: Because of these reasons, this project has been preferred to research the effects of thinner on oxidant and antioxidant status. METHODS: Totally 46 rats were included in the study. Thirty six rats were separated into six groups with 10 rats in a control group. The first group inhaled thinner for 2 weeks, and the other groups were exposed to thinner for 4, 6, 8, 10 and 12 weeks for 1 h twice a day. On the mentioned duration, rats were autopsied. Lung tissues malondialdehyde (MDA), glutathione (GSH) levels and superoxide dismutase (SOD) activities were determined to designate the oxidant-antioxidant balance. RESULTS: We observed an increase in MDA values both in the acute and the subacute periods. In the chronic period by the consuming of lipid peroxidation products, MDA values decreased and as the oxidative stress continued MDA values again increased. We observed that especially GSH values that has antioxidant feature, decreased until 6 weeks in order to compensate lipid peroxidation products. In the consuming period of lipid peroxidation, the values became fixed and later, these values again increased. There was no relationship between the changing values of MDA and SOD. CONCLUSIONS: Thinner is an agent that causes oxidative stress and inhalation of high doses of thinner causes harm to the respiratory system. As there are few reports in the literature on long-term effects of thinner inhalation, more studies might be necessary.

The effects of antioxidants on exercise-induced lipid peroxidation in patients with COPD.

OBJECTIVE: The oxidant-antioxidant balance plays an important role in the pathogenesis of COPD. The aim of the present study was to evaluate the effects of exercise, as an oxidative stress factor on the oxidant-antioxidant balance and to investigate whether short-term antioxidant treatment affects lipid peroxidation products. METHODOLOGY: Twenty-one stable COPD patients and 10 control subjects were included in the study. Symptom-limited exercise tests were performed by all subjects. Blood was collected before and 1 h after exercise in control subjects and before, 1 and 3 h after exercise in COPD patients, for analysis of malondialdehyde (MDA), reduced glutathione (GSH) and vitamin E (VE) levels. VE and vitamin C treatments were added to the regular bronchodilator therapy in 10 COPD patients for 1 month. After the treatment period, an exercise test was performed and blood was collected again for MDA, GSH and VE levels. RESULTS: Baseline GSH and VE levels were significantly lower in the COPD group when compared with the control subjects. There was no statistically significant difference in MDA levels between the two groups. In the COPD group, MDA levels 3 h after exercise were significantly higher than at baseline. In contrast there were no significant differences in MDA, VE and GSH levels in the control group after exercise. VE and MDA levels increased significantly after exercise in COPD patients but there was no difference in GSH levels. Baseline exercise time was significantly lower in the COPD group than in the controls. In 10 COPD patients who were given antioxidant therapy, their exercise time increased significantly and there was no increase in MDA and VE levels after the repeated exercise test. CONCLUSIONS: Antioxidant levels were significantly lower in COPD patients than in control subjects. In these patients, exercise results in more significant oxidative stress and lipid peroxidation than in control subjects and antioxidant therapy may decrease lipid peroxidation following exercise and improve exercise capacity.

Protective effect of IGF-1 on experimental liver cirrhosis-induced common bile duct ligation.

BACKGROUND/AIMS: The causes of malnutrition in liver cirrhosis are multifactorial. Levels of IGF-1 (insulin like growth factor-1) that is a crucial regulator of intermediary metabolism decreases. The aim of this study was to analyze the effect of IGF-1 supplementation during liver cirrhosis induced by common bile duct ligation. METHODOLOGY: Rats were divided into five different groups: One sham and four experimental groups. Rats in three of four groups were treated with 2 micrograms/day IGF-1 with a different time of experiment in each group. Blood biochemical parameters, tissue malondialdehyde, glutathione levels and the activity of tissue antioxidant enzymes and conventional and immunohistochemical analysis of liver samples were studied for each group. RESULTS: Serum albumin, total protein, fibrinogen levels decreased and prothrombin time was prolonged in the bile duct ligated and transected experimental group but not in the IGF-I treated rats compared with the rats in sham group. Liver malondialdehyde levels significantly increased in control group but not in IGF-1 treated groups. The activities of antioxidant enzymes were decreased compared with the other groups. Histopathology findings of liver biopsy demonstrated intense degree fibrosis and overexpression of fibroblast growth factor and desmin in the control group but a lesser degree of those in the IGF-1 treated groups. CONCLUSIONS: IGF-1 treatment improves liver function and decreases oxidative liver damage and histopathological findings. Further studies are required to delineate the mechanisms of protective effects of IGF-1.

Hemostatic system as a risk factor for cardiovascular disease in women with subclinical hypothyroidism.

Hypothyroidism has been associated with atherosclerosis. The mechanisms of atherosclerosis in patients with thyroid failure remain controversial. Hypofibrinolysis might be a risk factor for thromboembolic disease in subclinical hypothyroidism (SH). We measured fibrinolytic activity in patients with SH before and after levothyroxine (LT(4)) treatment and compared it to those of controls. We prospectively included 35 patients with SH and 30 healthy controls. We treated patients with LT(4) until almost 6 months after the euthyroid state has been achieved. We measured fibrinogen, D-dimer, antithrombin III (ATIII), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) activity, and factor VII. Clinical and anthropometric variables were recorded for both groups. We found increased levels of fibrinogen, PAI-1, and factor VII and decreased levels of ATIII activity in patients compared to control (p < 0.001 and p < 0.05). Decrease of tPA was not significant (p > 0.05). At the end of the LT(4) treatment, significant decreases were determined in PAI-1 and factor VII (p < 0.05). In conclusion, our data suggest an important role of hypofibrinolytic and hypercoagulable state on the development of atherosclerosis in patients with SH and beneficial effects of LT(4 )treatment for decreasing the risk of atherosclerosis.

Lipid profile and lipoprotein (a) as a risk factor for cardiovascular disease in women with subclinical hypothyroidism.

This study evaluated changes of lipids and lipoprotein (a) [Lp (a)] as atherosclerotic risk factors and the effects of levothyroxine (LT4) treatment on these parameters in patient with subclinical hypothyroidism (SH), defined by increased concentrations of thyrotropin (TSH) and normal thyroid hormone concentrations. We prospectively included 35 female patients with SH and 30 healthy controls. Serum lipid measurements and clinical score as well as fT3, fT4, and TSH levels were assessed at baseline. Body mass index (BMI) was also calculated. Women with proven SH received LT4 treatment that continued for 6 months. Twenty-six of 35 patients completed the study. At the end of treatment period, the same parameters were determined. Total cholesterol was significantly increased in patients with SH when compared with those of controls (p < 0.01), but increase of LDL-cholesterol (LDL-C) and Lp (a) were not significant (p > 0.05). In the levothyroxine-treated group, total cholesterol and LDL-C were significantly reduced when compared with the baseline values of women with SH (p < 0.05). Zulewski clinical score assessing symptoms and signs of hypothyroidism improved significantly with treatment (p < 0.001). In conclusion, serum lipids as important atherosclerotic risk factors increased before treatment and decreased with treatment. Levothyroxine therapy is effective in SH and improvements in serum lipids suggests that LT4 treatment also decreases the risk of atherosclerotic diseases.

Plasma lipid and lipoprotein concentrations in pregnancy induced hypertension.

OBJECTIVES: Aim of this study was to evaluate implication of pregnancy induced hypertension on maternal plasma lipid, lipoprotein, apolipoprotein concentrations and lipid peroxidation products by a comparison of normal pregnancy vs. preeclampsia. DESIGN AND METHODS: Thirty-four women with preeclampsia and 32 healthy pregnant women (controls) in the third trimester were recruited for this study. RESULTS: In the preeclamptic group plasma total triglyceride, low density lipoprotein cholesterol (LDL-C), malondialdehyde (MDA) and apolipoprotein B (apo-B) were significantly increased, while plasma high density lipoprotein cholesterol (HDL-C) was significantly decreased compared to that of control group. There was no significant difference in total cholesterol and apolipoprotein A1 (apo-A1) concentrations. CONCLUSION: Our findings suggest that preeclampsia share some metabolic characteristics with coronary artery disease such as dislipidemia and increased lipid peroxidation. However lipoprotein concentrations may be better biochemical markers of dislipidemia in the preeclamptic state than the corresponding apolipoproteins.

Erythrocyte glutathione peroxidase activity, plasma malondialdehyde and erythrocyte glutathione levels in hemodialysis and CAPD patients.

OBJECTIVES: Cardiovascular disease is the major cause of mortality in patients receiving hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) due to chronic renal failure. Increased lipid peroxidation and depletion of antioxidants may contribute to increased risk of atherosclerosis. We have therefore assessed the effect of hemodialysis and CAPD on oxidant and antioxidant status. DESIGN AND METHODS: Plasma malondialdehyde (MDA), Glutathione (GSH) levels and glutathione peroxidase (Gpx) activities were determined in 20 healthy persons (control), 20 patients on HD, 16 patients on CAPD. RESULTS: MDA was elevated in posthemodialysis and CAPD patients in comparison to prehemodialysis and control groups (posthemodialysis 1.39 +/- 0.38 nmol/mL, CAPD 1.26 +/- 0.27 nmol/mL, prehemodilaysis 0.83 +/- 0.22 nmol/mL, controls 0.72 +/- 0.21 nmol/mL p < 0.0001). With respect to antioxidants, glutathione levels were significantly lower in prehemodialysis, posthemodialysis and CAPD groups than those in control group (prehemodialysis 16.82 +/- 6.73 mg/dL RBC, posthemodialysis 31.43 +/- 11.88 mg/dL RBC, CAPD 40 +/- 12.72 mg/dL RBC, controls 62.26 +/- 24.01 mg/dL RBC, p < 0.0001). While erythrocyte GSH levels were significantly lower in the prehemodialysis patients than those in posthemodialysis and CAPD patients (p < 0.0001), it was significantly lower in posthemodialysis patients than those in CAPD patients (p < 0.05). There were no significant differences with respect to erythrocyte Gpx levels among the groups (p > 0.05). CONCLUSIONS: These findings indicate oxidative stress in patients with chronic renal failure which is further exacerbated by hemodialysis and CAPD, as evidenced by increased lipid peroxidation and low antioxidant levels.