Effect of Ptosis Surgery on Tear Oxidative Stress Levels in Patients with Blepharoptosis and Pseudoptosis.

Objectives: Investigation of the surgical correction effect on tear film functions and tear oxidative stress levels in patients with blepharoptosis and pseudoptosis. Methods: Sixty patients with blepharoptosis or pseudoptosis due to dermatochalasis and 30 healthy controls were included in the study. Forty eyes underwent upper blepharoplasty and 20 eyes underwent levator surgery. The tear oxidative stress levels (8-hydroxydeoxyguanosine [8-OHdG] and 4-hydroxy-2-nonenal [4-HNE]) were determined by enzyme-linked immunosorbent assay and tear film functions were evaluated pre-operatively and at the post-operative 1st and 6th months. Results: 8-OHdG and 4-HNE levels in tears were found higher in patients with dermatochalasis (86.3±38.2 ng/mL; 29.8±11.4 ng/mL, respectively) and blepharoptosis (95.3±43.8 ng/mL; 40.8±3.8 ng/mL, respectively) compared to healthy controls (52.9±14.0 ng/mL; 27.8±6.6 ng/mL, respectively). Both levels decreased 1 month after blepharoplasty surgery. The 8-OHdG level in tears of patients who underwent levator surgery increased 1 month after the surgery (p=0.008). No change was detected in tear function tests findings between visits in any patient group. Conclusion: Dermatochalasis and blepharoptosis may lead to an increase in the tear oxidative stress levels. Contrary to a decrease in these levels after blepharoplasty, they may increase in the early period after levator surgery followed by a return to normal levels at the 6th-month visit.

Do neurosteroids have impact on depression and cognitive functions in cases with acromegaly?

OBJECTIVE: Neurosteroids (NSs) are a distinct hormone group and, they are known for their contribution into the status of mood and cognitive functions. Whether they are also involved in the mood disturbances and cognition in acromegaly is not known. Herein we aimed to evaluate the relation of mood status and cognitive functions with the NS levels in cases with acromegaly. DESIGN: A total of 33 cases with acromegaly composed the acromegaly group (AG) and, 30 age and gender-matched cases without acromegaly composed the control group (CG). The levels of Allopregnanolone (AP), pregnenolone (PRG), 24S-hydroxycholesterol (24OHC), dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), androsterone (ADT), GH and IGF-1 were measured in each group. Beck Depression Inventory (BDI) was used to assess depressive symptoms, whereas an extensive neuropsychological assessment with several neurocognitive tests were carried out for each subject by an experienced psychologist. RESULTS: Cases with acromegaly had lower 24OHC and DHEA levels (p = 0.002 and p = 0.007, respectively) in comparison to CG. Of the cognitive functions time to complete 1 s Series was significantly higher and, the scores on Switching Verbal Fluency Test, Boston Naming Test (BNT)-semantic and BNT-phonological, the highest learning point of Oktem Verbal Memory Processes Test (VMPT) were significantly lower in cases with acromegaly in comparison to those in controls (p = 0.004, p = 0.01, p < 0.001, p = 0.02 and p = 0.05, respectively). KAS-perseveration errors were higher in CG (p = 0.03). In AG the levels of AP were negatively correlated with the scores on Months backward Test (MBT), Animal Naming Test, Construction, BNT-spontaneous and positively correlated with BNT-incorrect answers; PRG was positively correlated with VMPT-retention scores, ADT was negatively correlated with MBT and 3 s Series scores, DHEAS was positively correlated with VMPT-the highest learning point whereas it was negatively correlated with MBT scores. Additionally, the scores on BDI were positively correlated with DHEA levels in AG. CONCLUSION: Cognitive changes may be encountered in acromegaly and, neurosteroids may contribute to the changes in certain cognitive functions.

Relationship between LPA SNPs and inflammatory burden in patients with preeclampsia to address future cardiovascular risk.

OBJECTIVE: The study tested whether cardiovascular corresponding LPA risk genotypes improve pre-eclampsia and coronary heart disease (CHD) risk prediction beyond conventional risk factors. BACKGROUND: Studies have shown that women specific risk factors for cardiovascular disease (CVD) have taken an attention recently. It might be possible to identify women who have the highest risk in developing CVD in their further lives. It is well-known that Lp(a) levels have an impact on increased risk of CVD which is affected by LPA gene. Further, LPA risk genotypes are not considered in cardiovascular risk prediction. METHODS: We have included 200 pregnant Turkish women into the study. We stratified the preeclamptic (PE) group: early (EOP) (28.7 ± 3.0 weeks) and late onset (LOP) (36.0 ± 1.4 weeks). 14 LPA SNPs were evaluated in the study. Rs9355296 and rs3798220 were found as independent risk factors for preeclampsia by logistic regression analysis. A positive correlation was found between rs9355296 and the diagnostic criteria of preeclampsia. Further rs9355296 G/* carriers have higher vascular inflammation rather than AA carriers. CONCLUSIONS: The findings reveal that LPA genetic variability with high inflammatory response might be an indication of future cardiovascular events.

The Relationship between the Waist Circumference and Increased Carotid Intima Thickness in Obese Children.

Background: This study aimed to evaluate the cardiometabolic risk factors in normotensive obese and hypertensive obese (HT-obese) children by comparison of anthropomorphic measurements, fat distribution, carotid artery intima-media thickness (CIMT), and inflammatory markers. Methods: Fifty-three obese patients 10-18 years of age with a BMI-for-age/gender >95th percentile and 20 age- and gender-matched healthy volunteers enrolled in the study. Obese patients were divided into two groups according to the presence of hypertension (HT), as follows: HT-obese subgroup (n = 30) and nonhypertensive obese (non-HT-obese) subgroup (n = 23). Results: Weight standard deviation score (SDS), BMI-SDS, waist circumference (WC) SDS, and the fat tissue z-score were significantly higher (p < 0.001 for all) in the obese patients than the control groups. Obese patients had higher 24-hour systolic blood pressure (SBP) SDS and leptin, high-sensitivity C-reactive protein, tumor necrosis factor-alpha, and interleukin-6 levels. Furthermore, CIMT and CIMT-SDS were significantly higher in them. HT-obese patients (n = 30) had significantly higher WC-SDS and lower serum leptin and adiponectin levels than those of non-HT-obese group (n = 23). Finally, an association between increased CIMT-SDS and WC-SDS (ß = 0.399, p = 0.002) and 24-hour SBP-SDS (ß = 0.272, p = 0.009) was shown. Conclusions: Association between increased WC and HT implies the importance of central obesity in atherosclerosis. We concluded that WC measurement could be used to define risk groups since it is related to cardiometabolic complications.

Leptin and ghrelin in chronic kidney disease: their associations with protein-energy wasting.

BACKGROUND: This study aimed to evaluate plasma concentrations of leptin and total ghrelin in children with chronic kidney disease (CKD) and assess their roles in protein-energy wasting (PEW). METHODS: This study consisted of three different CKD populations [CKD group (20 patients with non-dialysis CKD), dialysis group (39 patients on dialysis), and kidney transplant (KTx) group (35 KTx recipients)] and control group (18 healthy children). Plasma leptin and total ghrelin levels were measured. Multi-frequency bioimpedance analysis was used for the assessment of fat and lean mass. PEW was defined using criteria including body mass, muscle mass, growth, serum albumin level, and protein intake. RESULTS: While plasma leptin levels did not differ among the study groups, total ghrelin levels were significantly higher in the dialysis group (P < 0.001). Seven dialysis patients (18%) and one CKD patient (5%) but none of the KTx recipients met the criteria of PEW. Dialysis patients with PEW had lower plasma leptin levels compared to their counterparts (P = 0.018); however, total ghrelin levels did not differ between the two groups (P = 0.10). Low leptin level in dialysis patients was independently associated with lower fat mass index (P < 0.001) and lower height-specific SD scores of BMI (P = 0.019). CONCLUSIONS: PEW is prevalent in dialysis patients. Low levels of leptin seem to be associated with PEW. Our result suggests that low leptin levels may be a consequence rather than a cause of PEW. Longitudinal studies are required to investigate this complex relationship between leptin and PEW in pediatric dialysis patients.

Protective effects of pentoxifylline in small intestine after ischemia-reperfusion.

Objective This study was performed to determine the healing effects of pentoxifylline on molecular responses and protection against severe ischemic damage in the small intestine. Methods Thirty-six Wistar albino rats were divided into six groups. The superior mesenteric artery was clamped for 120 minutes, and reperfusion was performed for 60 minutes. Saline (0.4 mL), pentoxifylline (1 mg/kg), and pentoxifylline (10 mg/kg) were intraperitoneally administered to the rats in the C1, P1, and P3 groups, respectively, 60 minutes before ischemia and to the rats in the C2, P2, and P4 groups, respectively, during reperfusion onset. Malondialdehyde, myeloperoxidase, tumor necrosis factor alpha, interleukin-1 beta, and interleukin-6 in serum and tissue were measured by enzyme-linked immunosorbent assay. Intestinal ischemic injury was histopathologically evaluated by the Chiu score and immunohistochemical staining. Results All serum and tissue molecular responses were significantly blunted in the pentoxifylline-treated groups compared with the controls. Significant improvement in ischemic damage was demonstrated in the pentoxifylline-treated groups by histological grading and immunohistochemical scoring. Conclusions The protective effects of pentoxifylline were confirmed by molecular responses and histopathological examination.

Maternal serum copeptin concentrations in early- and late-onset pre-eclampsia.

OBJECTIVE: Early-onset pre-eclampsia is primarily associated with placental dysfunction, whereas late-onset pre-eclampsia is defined as a maternal constitutional disorder. As a protein cosynthesized with vasopressin, copeptin is a potential marker of metabolic syndrome and insulin resistance, which shares similar risk factors with pre-eclampsia. The aim of this study was to investigate the copeptin levels in patients with early-onset and late-onset pre-eclampsia. MATERIALS AND METHODS: A total of 80 pregnant women receiving antenatal and obstetric care were recruited. The patients were subdivided into four groups: Early-onset pre-eclampsia (n = 20), late-onset pre-eclampsia (n = 20), and two control groups of similar gestational ages for both pre-eclamptic groups (n = 20 in each group). The maternal serum copeptin levels were measured using an enzyme-linked immunosorbent assay. RESULTS: The mean copeptin levels were 0.92 ± 0.57 ng/mL and 1.65 ± 0.95 ng/mL in the early-onset and late-onset pre-eclampsia groups, respectively. These values were higher compared with the control groups (0.54 ± 0.25 ng/mL and 1.15 ± 0.94 ng/mL, respectively). However, the difference was only statistically significant in the early-onset pre-eclampsia group (p = 0.011). Copeptin levels were associated only with gestational age and systolic-diastolic blood pressure. CONCLUSION: Our results suggest that copeptin levels might be useful in the evaluation of the severity of pre-eclampsia. However, copeptin might be involved in early- rather than late-onset pre-eclampsia.

Evaluation of advanced oxidation protein products, prooxidant-antioxidant balance, and total antioxidant capacity in untreated vitiligo patients.

BACKGROUND: Vitiligo is a chronic, common disease of unknown etiology, and oxidative stress is suggested to have a role in its etiopathogenesis. OBJECTIVE: Advanced oxidation protein products (AOPPs), prooxidant-antioxidant balance (PAB), and ferric-reducing antioxidant power (FRAP) were evaluated regarding their role in the pathogenesis of vitiligo as well as their relationship with clinical presentation and disease severity, and these parameters were compared with those of healthy controls. METHODS: The study included 53 patients with vitiligo and 20 healthy volunteers as the control group. AOPP level, PAB, and FRAP were determined by colorimetric methods. RESULTS: PAB and FRAP level were significantly higher in patients with vitiligo than in healthy controls (p<0.001). The AOPP levels in vitiligo patients were not statistically significantly higher than those in healthy controls. The Vitiligo Area Scoring Index positively correlated with disease duration (rs: 0.531, p<0.001). CONCLUSION: To the best of our knowledge, this is the first report of AOPP and PAB status in vitiligo. PAB may be used as an indicator for oxidative stress in the etiopathogenesis of vitiligo. Our results show that these parameters may play a major role in the melanocyte damage observed in vitiligo. Further studies are required to confirm the mechanisms underlying this effect.

Malnutrition and its association with inflammation and vascular disease in children on maintenance dialysis.

BACKGROUND: Malnutrition is associated with both inflammation and atherosclerotic cardiovascular disease in adults with chronic kidney disease. We studied the prevalence of malnutrition and its possible associations with inflammation and vascular disease in children on chronic dialysis. METHODS: Thirty-three patients on maintenance dialysis (18 peritoneal dialysis, 15 hemodialysis) and 19 age- and gender- matched healthy controls were studied. Nutritional status was assessed by anthropometric measurements including body mass index (BMI), upper arm measurements, multifrequency bioimpedance analysis (BIA) and serum levels of albumin, prealbumin, and cholesterol. Inflammation was assessed by serum levels of C-reactive protein (CRP), interleukin (IL)-6, and tumor necrosis factor (TNF)-alpha. The carotid artery intima thickness (cIMT) was measured to assess vascular disease. RESULTS: Compared with healthy children, patients had lower anthropometric measurements (P < 0.05) and serum albumin level (P < 0.001), and higher CRP and TNF-alpha (P = 0.030 and P = 0.007, respectively), and higher cIMT-SDS (P < 0.001). Malnutrition was present in 8 (24%) and lower BIA-based fat mass was independently associated with higher IL-6 levels (P = 0.035). An increased cIMT was present in 16 (48.5%); however, there was no difference in cIMT-SDS between patients with and without malnutrition. Carotid IMT did not show any association with nutritional indices; but positively correlated with serum IL-6 (P = 0.037), CRP (P = 0.012), and iPTH (P = 0.009), and independently associated with only iPTH (P = 0.018). CONCLUSIONS: Children on dialysis are at an increased risk of malnutrition, inflammation, and vascular disease. Although each of these three conditions exists, there is no interaction among them all. We postulate that the malnutrition-inflammation-atherosclerosis (MIA) complex might not exist in pediatric dialysis patients.

Copeptin concentrations are not elevated in gestational diabetes mellitus.

PURPOSE: To investigate copeptin levels in women with GDM and women with uncomplicated pregnancies. METHODS: This case-control study was conducted on 45 women with GDM and 40 women with uncomplicated pregnancies. The maternal serum levels of copeptin were measured with enzyme-linked immunosorbent assay. RESULTS: Copeptin levels were not different among groups (0.93 ± 0.75 vs. 1.15 ± 0.93 ng/ml, p: 0.24). HOMA-IR and insulin levels were significantly higher in woman with GDM when compared with control group (2.90 ± 1.88 vs. 1.91 ± 0.50, p: 0.002; 11.74 ± 6.43 vs. 8.52 ± 2.28, p: 0.004, respectively). The copeptin concentrations were significantly correlated with insulin levels and HOMA-IR values (r = 0.329 p = 0.002, r = 0.289 p = 0.007, respectively). CONCLUSIONS: The present study shows that serum copeptin concentrations did not differ in woman with GDM and non-GDM patients. However, we found a significant correlation between copeptin and HOMA-IR. Future studies are needed with larger populations in gestational diabetic patients on copeptin secretion, metabolism and action.

Effects of serum homocysteine and adiponectin levels on platelet aggregation in untreated patients with essential hypertension.

The aim of the present study is to determine and correlate adiponectin, homocysteine, nitric oxide, and ADP-induced platelet aggregation levels in untreated patients with essential hypertension and healthy individuals. A total of 36 individuals, 23 untreated patients with essential hypertension and 13 healthy individuals, were included in the scope of this study. Enzyme-linked immunosorbent assay (ELISA) was used to determine the serum adiponectin and TNF-alpha levels. The levels of serum homocysteine were measured by using competitive chemiluminescent enzyme immunoassay. Serum concentrations of hsCRP were measured by the Nephelometer. Plasma nitrite, nitrate, and total nitric oxide (NOx) levels were determined by colorimetric method. Homocysteine and hsCRP levels in patients with essential hypertension were found to be significantly higher than those in the control group (P = 0.02, P = 0.001, respectively). The average platelet aggregation levels in patient group were higher than control group, but there were no statistically significant differences between them (P > 0.05). In addition, in patients with essential hypertension adiponectin and nitrite levels are significantly lower than control group (P < 0.001, P = 0.045, respectively). We have also found significant correlations between nitrite-platelet aggregation amplitude, nitrite-platelet aggregation slope, nitrite-adiponectin, homocysteine-platelet aggregation amplitude, and sistolic blood pressure-platelet aggregation amplitude levels (r = -0.844; P < 0.001, r = -0.680; P = 0.011, r = 0.454; P = 0.05, r = 0.414; P = 0.05, r = 0.442; P = 0.035, respectively). Increased homocysteine and decreased adiponectin serum levels in patients with essential hypertension correlate well with changes in ADP-induced conventional platelet aggregation. This association may potentially contribute to future thrombus formation and higher risks for cardiovascular events in hypertensive patients.

Effects of rhG-CSF plus dexamethasone on hemostatic parameters in healthy granulocyte donors: role of u-PA and nitric oxide.

Granulocyte colony-stimulating factor (G-CSF) is widely used to reduce the risk of infection resulting from neutropenias and to mobilize and collect CD34+ hematopoetic progenitor cells (HPCs) for autologous and allogenic transplantation. The safety of recombinant human G-CSF (rhG-CSF) administration in healthy donors has been investigated in several studies. However, there are limited cumulative data about the effects of rhG-CSF on hemostasis. Hemostatic parameters, including urokinase-type plasminogen activator antigen (u-PA:Ag) and nitric oxide in 17 healthy granulocyte apheresis donors who donated for neutropenic patients were evaluated. rhG-CSF (single dose, 10 microg/kg subcutaneously) and dexamethasone (8 mg, single dose oral) were given to donors 12 hours before granulocyte apheresis. Two blood samples were drawn at time 0 (T(0)) before rhG-CSF and dexamethasone administration and at time 1 (T1), immediately before the apheresis. A statistically significant rise in coagulant factor VIII (FVIII) and von Willebrand factor (vWF), and slightly rise in u-PA:Ag were observed after G-CSF plus dexamethasone administration. In addition, there were positive correlations between vWF-D-dimer and FVIII-D-dimer. A significant decrease in mean total nitric oxide (NOx), nitrite, and nitrate levels was also found after G-CSF plus dexamethasone administration. Moreover, there was a strong negative correlation between nitrite and D-dimer levels (r = -0.611; P = .009). Even if partially compensated with u-PA and protein C, increased FVIII and vWF activity, and decreased nitric oxide levels may still partially contribute to progress of thrombosis risk in rhG-CSF plus dexamethasone administered healthy granulocyte donors. Large numbers of healthy donors exposed to G-CSF plus dexamethasone will be needed to evaluate the risk of thrombosis in this population.

Plasma paraoxonase activities, lipoprotein oxidation, and trace element interaction in asthmatic patients.

Paraoxonase (PON1) protects low and high-density lipoproteins (LDL and HDL) against oxidation induced by reactive oxygen species formation facilitated by iron (Fe) and copper (Cu) ions. Plasma PON1, arylesterase, oxidized LDL (Ox-LDL), Cu, Fe, thiobarbituric acid-reactive substances (TBARS), lipid, lipoprotein, and apolipoprotein profile in bronchial asthma were determined and the relations among these parameters in different steps of asthma were interpreted. A total of 58 individuals, 30 asthmatics and 28 controls, were included into the scope of this study. Plasma PON1, arylesterase, and TBARS levels were measured spectrophotometrically. Determination of plasma oxidized LDL, Cu, and Fe levels were performed by enzyme-linked immunosorbent assay, atomic absorption spectrophotometry, and the automated TPTZ method, respectively. Apo-A-1 and Apo-B levels were determined immunoturbidometrically. Plasma total cholesterol, triglyceride, and HDL cholesterol levels were enzymatically determined. Plasma LDL levels were estimated using the Fridewald formula. The average plasma PON1 and arylesterase activities in the group of patients were lower than those of the individuals in the control group, but there was no statistically significant difference found between them (p > 0.05). No significant difference was found in plasma Apo-A-1, Apo-B, total cholesterol, triglyceride, HDL, and LDL concentrations between the control and patient groups (p > 0.05). Plasma oxidized LDL (p < 0.05), Cu (p < 0.01), Fe (p < 0.01), and TBARS (p < 0.001) levels in patients with asthma were found to be significantly higher than for the control group. Increases in Cu, Fe, lipid peroxidation, and oxidized LDL levels supported by relative decreases in PON1 activities observed in asthmatic patients might be introduced as the striking findings as well as the possible potential indicators of this airway disease, the prevalence of which has increased dramatically over recent decades.

Vitronectin in atherosclerotic disease.

Atherosclerosis is characterized by the development of an intimal thickening that contains monocytes, T lymphocytes, and smooth muscle cells within an accumulation of lipid and extracellular matrix proteins. Vitronectin is a plasma glycoprotein implicated as a regulator of diverse physiological process, including blood coagulation, fibrinolysis, pericellular proteolysis, complement dependent immune responses, and cell attachment and spreading. Because of its ability to bind platelet glycoproteins and mediate platelet adhesion and aggregation at sites of vascular injury, vitronectin has become an important mediator in the pathogenesis of coronary atherosclerosis.

Angiotensin-converting enzyme and metals in untreated essential hypertension.

Hypertension is an important health problem throughout the world and a risk factor for many diseases. Angiotensin-converting enzyme (ACE), a component of the renin-angiotensin system, has an important role in the regulation of blood pressure. Zinc (Zn), a trace element with important biological functions, is located in the catalytic site of ACE. Calcium (Ca), magnesium (Mg), sodium (Na), and potassium (K) also appear to be involved in hypertension pathogenesis. In this study, plasma ACE activities and Cat, Cai, Mg, Na, K, and plasma/erythrocyte Zn levels of 20 untreated patients with essential hypertension and 28 healthy individuals were evaluated. Plasma ACE activities (p<0.05) and erythrocyte Zn concentrations (p<0.001) were significantly higher in patients with essential hypertension than values of the control group. No significant difference was found between plasma Zn concentrations of the groups (p>0.05). Plasma Cat (p<0.001) and Mg levels (p<0.05) in essential hypertension were significantly lower than those of controls. Plasma Na, K, and Cai levels remained normal in essential hypertension. There are complex associations between metals and arterial pressure. Ca and Mg deficiencies seem to be associated with increased prevalence of hypertension. Increases in erythrocyte Zn may have a future potential use for diagnosis of hypertension.

Interleukin-8, nitric oxide and glutathione status in proliferative vitreoretinopathy and proliferative diabetic retinopathy.

PURPOSE: To evaluate interleukin-8 (IL-8), nitric oxide (NO) and glutathione (GSH) profiles in vitreous humor and blood samples in patients with proliferative diabetic retinopathy (PDR) and in patients with proliferative vitreoretinopathy (PVR) and to compare the levels with those of controls. PATIENTS AND METHODS: NO concentrations were determined by using the Greiss reaction in plasma and vitreous humor samples. GSH levels were determined in both blood and vitreous humor samples, using DTNB, a disulfide chromogen. Vitreous IL-8 were assayed by ELISA. Twenty-three patients with PDR, 18 patients with PVR and 21 cadavers as the control group were included in the study. RESULTS: Plasma and vitreous NO levels were found to be 25.6 +/- 2.1 and 36.9 +/- 3.0 micromol/l in patients with PDR, 27.0 +/- 4.7 and 34.3 +/- 2.9 micromol/l in patients with PVR and 17.4 +/- 2.7 and 15.9 +/- 1.4 micromol/l in controls, respectively. Vitreous humor and plasma NO levels did not show any statistically significant difference between PDR and PVR groups. However, the values for vitreous in both groups were significantly higher than those of controls (p < 0.0001). Although IL-8 levels in vitreous samples of patients with PDR were not significantly different (79.6 +/- 9.7 pg/ml) from those of patients with PVR (42.2 +/- 7.3 pg/ml) (p = 0.06), the levels in both groups were significantly higher than those of controls (19.0 +/- 3.9 pg/ml) (p < 0.0001 and p < 0.05, respectively). Blood and vitreous GSH levels were found to be 5.3 +/- 0.4 micromol/g. Hb and 0.58 +/- 0.16 micromol/l in patients with PDR and 8.4 +/- 0.5 micromol/g. Hb and 15.7 +/- 2.2 micromol/l in patients with PVR and 12.0 +/- 1.1 micromol/g. Hb and 0.26 +/- 0.03 mmol/l in controls, respectively. Vitreous and blood GSH levels were significantly lower in patients with PDR compared to those with PVR (p < 0.0001 for both). CONCLUSION: Elevated levels of vitreous and plasma NO and vitreous IL-8 in PDR and PVR implicate a role for these parameters in the proliferation in these ocular disorders. GSH concentrations both in vitreous and blood samples of the PVR and PDR patients were much less than those observed in the control group. Lower GSH concentrations detected in PDR in comparison with those in PVR in vitreous humor and to a lesser degree in blood may play an important role in pathogenesis of new retinal vessel formation in patients with PDR. This also suggests that oxidative stress may be involved in the pathogenesis of PVR and particularly that of PDR.