Characteristics of Turkish children with Type 2 diabetes at onset: a multicentre, cross-sectional study.

AIMS: To describe the baseline clinical and laboratory findings and treatment modalities of 367 children and adolescents diagnosed with Type 2 diabetes in various paediatric endocrinology centres in Turkey. METHODS: A standard questionnaire regarding clinical and laboratory characteristics at onset was uploaded to an online national database system. Data for 367 children (aged 6-18 years) newly diagnosed with Type 2 diabetes at 37 different paediatric endocrinology centres were analysed. RESULTS: After exclusion of the children with a BMI Z-score < 1 SD, those with genetic syndromes associated with Type 2 diabetes, and those whose C-peptide and/or insulin levels were not available, 227 cases were included in the study. Mean age was 13.8 ± 2.2 (range 6.5-17.8) years, with female preponderance (68%). Family history of Type 2 diabetes was positive in 86% of the children. The mean BMI was 31.3 ± 6.5 kg/m2 (range 18.7-61) and BMI Z-score was 2.4 ± 0.8 (range 1-5). More than half (57%) of the children were identified by an opportunistic diabetes screening due to existing risk markers without typical symptoms of diabetes. Only 13% (n = 29) were treated solely by lifestyle modification, while 40.5% (n = 92) were treated with metformin, 13% (n = 30) were treated with insulin, and 33.5% (n = 76) were treated with a combination of insulin and metformin initially. Mean HbA1C levels of the insulin and combination of insulin and metformin groups were 98 (11.1%) and 102 mmol/mol (11.5%), respectively, and also were significantly higher than the lifestyle modification only and metformin groups mean HbA1C levels (70(8.6%) and 67 mmol/mol (8.3%), respectively). CONCLUSIONS: An opportunistic screening of children who are at high risk of Type 2 diabetes is essential, as our data showed that > 50% of the children were asymptomatic at diagnosis. The other important result of our study was the high rate of exclusion from the initial registration (38%), suggesting that accurate diagnosis of Type 2 diabetes in youth is still problematic, even for paediatric endocrinologists.

Significance of S100A8, S100A9 and calprotectin levels in bladder cancer.

OBJECTIVES: Members of the S100 protein family, S100A8, S100A9 and their heterodimer complex known as calprotectin are thought to be involved not only in inflammatory pathways but also in tumorigenesis and cancer progression. Therefore, they have been widely studied in various types of cancer; however, there is limited knowledge about their role in bladder cancer. In this study, our aim was to determine the levels of S100A8 and S100A9 in the sera, and calprotectin levels in the sera and urines of bladder cancer patients and compare it to urinary BTA, a tumor marker that can be used in the diagnosis of bladder cancer. MATERIALS AND METHODS: The study was comprised of two major groups: 52 healthy controls and 82 patients with bladder cancer. The patient group was also divided into subgroups according to tumor stage and grade. Urine BTA levels, serum S100A8 and S100A9 levels, and serum and urine calprotectin levels in healthy controls and patients were determined using commercially available ELISA kits. RESULTS: While serum S100A8 and S100A9 levels did not differ between the controls and patients significantly, serum and urine calprotectin levels and urine BTA levels were significantly elevated in patients compared to controls. Serum calprotectin or urine BTA levels did not differ significantly among the patient subgroups. However, urine calprotectin levels were significantly elevated in muscle-invasive tumors (T2-4) compared to lower stages (Ta and T1). CONCLUSIONS: Urine calprotectin levels can be used in the diagnosis and staging of bladder cancer as a marker for muscle invasion.

Significance of serum c-erbB-2 oncoprotein, insulin-like growth factor-1 and vascular endothelial growth factor levels in ovarian cancer.

OBJECTIVES: Our aim was to determine the predictive values of serum levels of several growth factors in ovarian cancer, including soluble c-erbB-2 oncoprotein, insulin-like growth factor-1 (IGF-1) and vascular endothelial growth factor (VEGF). BACKGROUND: Previous studies have shown that growth factors play an important role in carcinogenesis. METHODS: Two groups were established. One of them was the malignant group which included 41 patients with ovarian carcinoma and the other was the control group that was made up of 28 healthy volunteers. Preoperative serum samples were obtained from the patients, and c-erbB-2, IGF-1 and VEGF levels were measured in these samples using ELISA. Serum CA-125 levels were also determined, by chemiluminescent microparticle immunoassay. RESULTS: VEGF levels of the malignant group were significantly higher than those of the control group (p < 0.01). CA-125 levels were also significantly higher than the in control group (p < 0.001). Area under the ROC curve (AUC) was 0.982 for CA-125, 0.780 for VEGF, 0.603 for c-erbB-2, and 0.467 for IGF-1 in differentiating cancers from controls. CONCLUSION: Serum VEGF levels might be a predictor for diagnosis in ovarian cancer patients, while serum c-erbB-2 and IGF-1 levels do not have a clinical significance in terms of ovarian cancer (Tab. 1, Fig. 1, Ref. 46).

Expanding the Clinical Spectrum Associated With GLIS3 Mutations.

CONTEXT: GLIS3 (GLI-similar 3) is a member of the GLI-similar zinc finger protein family encoding for a nuclear protein with 5 C2H2-type zinc finger domains. The protein is expressed early in embryogenesis and plays a critical role as both a repressor and activator of transcription. Human GLIS3 mutations are extremely rare. OBJECTIVE: The purpose of this article was determine the phenotypic presentation of 12 patients with a variety of GLIS3 mutations. METHODS: GLIS3 gene mutations were sought by PCR amplification and sequence analysis of exons 1 to 11. Clinical information was provided by the referring clinicians and subsequently using a questionnaire circulated to gain further information. RESULTS: We report the first case of a patient with a compound heterozygous mutation in GLIS3 who did not present with congenital hypothyroidism. All patients presented with neonatal diabetes with a range of insulin sensitivities. Thyroid disease varied among patients. Hepatic and renal disease was common with liver dysfunction ranging from hepatitis to cirrhosis; cystic dysplasia was the most common renal manifestation. We describe new presenting features in patients with GLIS3 mutations, including craniosynostosis, hiatus hernia, atrial septal defect, splenic cyst, and choanal atresia and confirm further cases with sensorineural deafness and exocrine pancreatic insufficiency. CONCLUSION: We report new findings within the GLIS3 phenotype, further extending the spectrum of abnormalities associated with GLIS3 mutations and providing novel insights into the role of GLIS3 in human physiological development. All but 2 of the patients within our cohort are still alive, and we describe the first patient to live to adulthood with a GLIS3 mutation, suggesting that even patients with a severe GLIS3 phenotype may have a longer life expectancy than originally described.

AR and SRD5A2 gene mutations in a series of 51 Turkish 46,XY DSD children with a clinical diagnosis of androgen insensitivity.

46,XY disorders of sex development (DSD) are caused by disorders of gonadal development, androgen biosynthesis and receptor (AR) defects. Although, clinical/biochemical features help in distinguishing specific aetiologies, there are overlaps which necessitate molecular analyses for the definitive diagnosis. To test precision of our clinical diagnosis of androgen insensitivity (AIS) by analysing AR and then SRD5A2 genes, patients were recruited at Marmara University Hospital and molecular analyses were performed at Vall d'Hebron Research Institute. Among 101 46,XY DSD patients, 46 index and five siblings (nine complete, 42 partial) with clinical/biochemical data suggestive of AIS and stimulated T/DHT ratio <25 were selected. AR and then SRD5A2 genes were sequenced. We detected AR mutations in 11 patients [seven index and four siblings (22% of all and 15% of index patients)] and SRD5A2 mutations in six [five index and one sibling (12% of all and 11% of index)]. AR mutation detection rate was 6/9 in all CAIS and 4/7 in the index (67 and 57% respectively) and 5/42 in all PAIS and 3/40 in the index (12 and 7.5% respectively). The eight mutations detected in the AR gene were as follows: p.Q58L, p.P392S, p.R609K, p.R775H, p.R856H, p.A871A, p.V890M and p.F892L, with p.A871A and p.F892L being novel. Further six patients had SRD5A2 mutations which were as follows: p.L73WfsX59, p.Y91H, p.R171S and p.G196S, the first being novel. Hormonal data in those with AR mutations, SRD5A2 mutations and no mutations were not statistically different. In conclusion, a significant proportion of children with presumptive diagnosis of AIS has a normal AR gene. The less severe the phenotype, the less likely is the chance of demonstrating a mutation. Furthermore, a significant number of children with presumptive diagnosis of AIS have mutations in SRD5A2 gene and are clinically and biochemically indistinguishable from AIS.

Ten novel mutations in the NR5A1 gene cause disordered sex development in 46,XY and ovarian insufficiency in 46,XX individuals.

CONTEXT: Steroidogenic factor-1 (SF-1/NR5A1) is a nuclear receptor that regulates adrenal and reproductive development and function. NR5A1 mutations have been detected in 46,XY individuals with disorders of sexual development (DSD) but apparently normal adrenal function and in 46,XX women with normal sexual development yet primary ovarian insufficiency (POI). OBJECTIVE: A group of 100 46,XY DSD and two POI was studied for NR5A1 mutations and their impact. DESIGN: Clinical, biochemical, histological, genetic, and functional characteristics of the patients with NR5A1 mutations are reported. SETTING: Patients were referred from different centers in Spain, Switzerland, and Turkey. Histological and genetic studies were performed in Barcelona, Spain. In vitro studies were performed in Bern, Switzerland. PATIENTS: A total of 65 Spanish and 35 Turkish patients with 46,XY DSD and two Swiss 46,XX patients with POI were investigated. MAIN OUTCOME: Ten novel heterozygote NR5A1 mutations were detected and characterized (five missense, one nonsense, three frameshift mutations, and one duplication). RESULTS: The novel NR5A1 mutations were tested in vitro by promoter transactivation assays showing grossly reduced activity for mutations in the DNA binding domain and variably reduced activity for other mutations. Dominant negative effect of the mutations was excluded. We found high variability and thus no apparent genotype-structure-function-phenotype correlation. Histological studies of testes revealed vacuolization of Leydig cells due to fat accumulation. CONCLUSIONS: SF-1/NR5A1 mutations are frequently found in 46,XY DSD individuals (9%) and manifest with a broad phenotype. Testes histology is characteristic for fat accumulation and degeneration over time, similar to findings observed in patients with lipoid congenital adrenal hyperplasia (due to StAR mutations). Genotype-structure-function-phenotype correlation remains elusive.

Diazoxide-responsive hyperinsulinemic hypoglycemia caused by HNF4A gene mutations.

OBJECTIVE: The phenotype associated with heterozygous HNF4A gene mutations has recently been extended to include diazoxide responsive neonatal hypoglycemia in addition to maturity-onset diabetes of the young (MODY). To date, mutation screening has been limited to patients with a family history consistent with MODY. In this study, we investigated the prevalence of HNF4A mutations in a large cohort of patients with diazoxide responsive hyperinsulinemic hypoglycemia (HH). SUBJECTS AND METHODS: We sequenced the ABCC8, KCNJ11, GCK, GLUD1, and/or HNF4A genes in 220 patients with HH responsive to diazoxide. The order of genetic testing was dependent upon the clinical phenotype. RESULTS: A genetic diagnosis was possible for 59/220 (27%) patients. K(ATP) channel mutations were most common (15%) followed by GLUD1 mutations causing hyperinsulinism with hyperammonemia (5.9%), and HNF4A mutations (5%). Seven of the 11 probands with a heterozygous HNF4A mutation did not have a parent affected with diabetes, and four de novo mutations were confirmed. These patients were diagnosed with HI within the first week of life (median age 1 day), and they had increased birth weight (median +2.4 SDS). The duration of diazoxide treatment ranged from 3 months to ongoing at 8 years. CONCLUSIONS: In this large series, HNF4A mutations are the third most common cause of diazoxide responsive HH. We recommend that HNF4A sequencing is considered in all patients with diazoxide responsive HH diagnosed in the first week of life irrespective of a family history of diabetes, once K(ATP) channel mutations have been excluded.

Prognostic significances of oxidative DNA damage evaluated by 8-hydroxy-deoxyguanosine and antioxidant enzymes in patients undergoing resection of gastric and colon carcinoma.

Oxidant/antioxidant balance has been suggested as an important factor for initiation and progression of cancer. In order to determine whether the degree of oxidative DNA damage and antioxidant enzyme activities in plasma obtained from patients with gastric and colon cancer who undergo resection can be used as a useful prognostic predictor, plasma level of 8-hydroxydeoxyguanosine (8-OHdG), activities of glutathione peroxidase (G-Px) and superoxide dismutase (SOD) were examined. 19 patients with gastric cancer and 26 patients with colon cancer who were undergoing resection of tumor were included by the study. Venous blood samples were taken just before the surgery. Plasma level of 8-OHdG was determined with ELISA, SOD and G-Px activities in plasma were measured by spectrophotometric kits. 8-OHdG level and activity of G-Px were found to be decreased, SOD activity was found to be increased in both gastric and colon cancer groups as compared to control group. Alpha fetoprotein was found to be correlated with G-Px in the gastric cancer group and correlated with 8-OHdG in the colon cancer group. SOD activity was correlated with CA-15-3 in the gastric cancer group. Low plasma level of 8-OHdG and altered antioxidant activity may implicate the deficient repair of oxidative DNA damage in patients with gastric and colon cancer. Those measured parameters were not found to be related with histopathological data but correlated with some tumor markers.

The relationship between antioxidant enzymes and bladder cancer.

Carcinogenesis proceeds through at least three distinct stages - initiation, promotion and progression. Free radicals play an important role in the multistep complex course of carcinogenesis. Urinary bladder has been recognized as a target organ for many carcinogens, including benzidine, beta-napthylamine, 2 napthylamine, 4-aminobiphenyl. Antioxidants have been shown to inhibit both initiation and promotion in carcinogenesis. The aim of presented study was to determine and compare the oxidant and antioxidant status in different clinical stages of bladder cancer and of control groups. Study was conducted in fifty-two (n=52) patients with transitional cell epithelial cancer of bladder and in twenty-four (n=24) healthy adults as plasma and erythrocyte controls. Malondialdehyde levels (4.636+/-1.118, 2.853+/-0.576 / 262.112+/-61.772, 203.788+/-35.340) were significantly higher and erythrocyte glutathione levels (6.272+/-1.708, 7.523+/-1.346) were significantly lower in bladder cancer patients group than in control group. Erythrocyte glutathione reductase and glutathione peroxidase (3.935+/-1.155, 5.481+/-1.626 / 8.729+/-1.614, 12.362+/-1.707) activities were significantly lower in cancer patients. In the other hand, glutathione S-transferase activities (3.100+/-1.177, 1.071+/-0.471) were found significantly increases. We suggest that the values of glutathione S-transferase enzyme activity can be used for a tumor detection approach and even as an indicator of the biological behavior of the bladder carcinoma.

DNA damage, DNA susceptibility to oxidation and glutathione level in women with polycystic ovary syndrome.

Recent studies have addressed the possibility of an association between polycystic ovaries and ovarian cancer. DNA damage is the first step of the carcinogenesis, and susceptibility to cancer, in general, is characterized by high DNA damage. Free radical-mediated DNA damage and impaired antioxidant defence have been implicated as contributory factors for the development of cancer. This study evaluates DNA damage (strand breakage, base oxidation, formamidopyrimidine DNA glycosylase (Fpg) sensitive sites), H2O2-induced DNA damage, a marker of DNA susceptibility to oxidation and glutathione (GSH) level, a powerful antioxidant, in women with polycystic ovary syndrome (PCOS). Women with PCOS showed a significant decrease in GSH level, a significant increase in DNA strand breakage and H2O2-induced DNA damage. Although Fpg-sensitive sites were higher in the PCOS group compared to the control group, the difference did not reach a statistically significant level. Significant correlations were found between free testosterone and DNA strand breakage (r = 0.46, p<0.01) and free testosterone and H2O2-induced DNA damage (r = 0.41, p<0.05). The data indicate that DNA damage and susceptibility of DNA to oxidative stress are increased in women with PCOS and may explain the association between PCOS and ovarian cancer.

Oxidative protein damage parameters in plasma in chronic experimental diabetes in rats.

An increase in oxidative stress may contribute to the development of oxidative protein damage (OPD) in the streptozotocin-diabetic rat. To show the effect of hyperglycemia in promoting OPD, we determined protein carbonyl (PCO), nitrotyrosine (NT), total thiol (T-SH) and advanced oxidation protein product (AOPP) levels as markers of OPD, and lipid hydroperoxide (LHP) levels as a marker of lipid peroxidation in plasma of acute and chronic diabetic male Sprague-Dawley rats and their controls. The levels of the studied markers, except NT, were determined by colorimetric methods. NT levels were measured by ELISA. Plasma PCO and AOPP levels of chronic diabetic rats were increased significantly compared with those of both acute diabetic rats and the controls. Plasma NT levels of the three groups were not different. Plasma T-SH levels of acute diabetics were increased significantly compared with those of the controls while T-SH increase in the chronic diabetics was not significant. Plasma LHP levels were increased significantly in the chronic diabetic rats compared with those of the controls. The increase in plasma PCO, AOPP, LHP levels in chronic but not in acute diabetic rats may be indicating that persistence of hyperglycemia is involved in the evolution of OPD while plasma NT levels do not seem to reflect OPD in diabetes.

Levels of plasma vitamin E, vitamin C, TBARS, and cholesterol in male patients with colorectal tumors.

Vitamin E and vitamin C are involved in the defense of the body against free radical and reactive oxygen molecule induced damage. The best characterized biological damage caused by radicals is known as lipid peroxidation. Free radical formation is known to play a major role in the development of cancer. In this study, we measured plasma levels of thiobarbituric acid reactive substances (TBARS) as a marker of lipid peroxidation, cholesterol, and vitamins E and C as antioxidants in male patients with colorectal tumors (n = 20, 54.5 +/- 8.3 years). The patients had significantly higher plasma TBARS levels than age-matched healthy subjects (p < 0.001). Plasma vitamin C levels were significantly lower in the patients compared to the healthy subjects (p < 0.001). On the other hand, plasma vitamin E levels in the patients were similar to those of healthy subjects. Plasma cholesterol levels were also found to be significantly elevated in patients with colorectal tumors (p < 0.001). Our results suggest that there is an imbalance between oxidant and antioxidant status in tumor genesis.

Effect of sex hormones on lipid peroxidation in women with polycystic ovary syndrome, healthy women, and men.

Recently, the influence of free radicals and lipid peroxides on many diseases, the effect of sex hormones on lipid peroxidation and antioxidant effects of estrogens have received considerable interest. In the present study we aimed to investigate the relationship between sex hormones and both lipid peroxidation and glutathione content in women with polycystic ovary syndrome (POS), in healthy women and in healthy men. We measured levels of lipid peroxides and sex hormones in plasma and levels of glutathione in erythrocytes of all cases. We evaluated the level of thiobarbituric acid reactive substances (TBARS) as an index of lipid peroxides and erythrocyte glutathione level as an index of antioxidant. We found that plasma levels of free testosterone, dehydroepiandrosterone sulfate (DHEAS) and estradiol significantly higher in the women with POS group than in the healthy women group. There was no significant difference in the levels of both plasma TBARS and erythrocyte glutathione, between women with POS group and healthy women group. Plasma DHEAS levels of healthy men and women with POS were similar. Plasma TBARS level was higher and erythrocyte glutathione level was lower in the healthy men group than in both the healthy women group and in the women with POS group. These data imply that testosterone has an oxidant effect. DHEAS which is an antioxidant, has a protective role in females with POS. Estrogens have an antioxidant effect but this action changes according to its dominant degradation pathway.

Lipid peroxidation and antioxidant status in maternal and cord blood.

The present study was undertaken to determine the change of blood lipid peroxide and antioxidant status in healthy nonpregnant women (n = 20), pregnant women in the third trimester (n = 20), pregnant women during delivery (n = 26) and fetal cord blood. Plasma and erythrocyte malondialdehyde (MDA) levels were found to be significantly higher and erythrocyte glutathione (GSH) levels were significantly lower in pregnant women in the third trimester than in nonpregnant women (p < 0.02, p < 0.03 and p < 0.001, respectively). The highest plasma and erythrocyte MDA levels and the lowest GSH levels were obtained from the pregnant women during delivery (6.99 +/- 2.35 nmol/ml, 283.20 +/- 43.81 nmol/g Hb, 6.73 +/- 2.34 micromol/g Hb, respectively). Erythrocyte glutathione peroxidase (GSH-P) and glutathione reductase (GSH-R) activities were not different between the groups. Maternal plasma and erythrocyte MDA levels were significantly correlated with cord blood plasma and erythrocyte MDA levels (r = 0.63, p < 0.001, and r = 0.41, p < 0.001, respectively). There was a significant positive correlation in GSH-R and in GSH-P activities between maternal and cord blood erythrocytes (r = 0.81, p < 0.001, and r = 0.79, p < 0.001, respectively). A significant correlation was found between maternal erythrocyte GSH-P and both cord blood erythrocyte GSH-R activities (r = 0.74, p < 0.001) and cord erythrocyte GSH levels (r = 0.73, p < 0.001). There was also a significant negative correlation between maternal erythrocyte MDA and cord erythrocyte GSH-R levels (r = -0.9, p < 0.001). Our results suggest that lipid peroxidation and antioxidant status may be changed during delivery, and these changes may affect the fetus by creating oxidative stress.

Relation of oxidative protein damage and nitrotyrosine levels in the aging rat brain.

An increase in oxidative stress may contribute to the development of oxidative protein damage in the aging rat brain. In the present study, we investigated the relation between nitrotyrosine levels and other oxidative protein damage parameters such as protein carbonyl and protein thiol, as well as oxidative stress parameters such as total thiol, nonprotein thiol, and lipid hydroperoxides in the brain tissue of young, adult, and old Wistar rats. Brain nitrotyrosine levels of old rats were significantly decreased compared with those of young rats. Young and adult rats were not significantly different as far as these parameters were concerned, however, brain protein carbonyl and lipid hydroperoxide levels of old rats were significantly increased compared with those of young and adult rats. On the other hand, brain tissue total thiol, nonprotein thiol, and protein thiol levels of old rats were significantly decreased compared with those of young and adult rats. The strong correlation we found between protein carbonyl and lipid hydroperoxide levels indicates a striking relation between protein oxidation and lipid peroxidation in the aging brain tissue. The results of this study suggest that protein carbonyl formation is both a sensitive and a specific marker of brain aging. However, decreased nitrotyrosine levels in old rats, in contradiction to the expected, may be due to mechanisms other than oxidative protein damage in the aging rat brain.

Effect of alpha-lipoic acid supplementation on oxidative protein damage in the streptozotocin-diabetic rat.

An increase in oxidative stress may contribute to the development of oxidative protein damage in streptozotocin diabetic rats. In the present study, the influence of alpha-lipoic acid supplementation on plasma protein carbonyl, plasma thiol, and plasma lipid hydroperoxide levels was examined in order to characterize the relationship between the oxidative stress and the oxidative protein damage. Rats were randomly divided into three groups of equal body weight. Chronic hyperglycemia was induced by intravenous streptozotocin injection in both the group of male Wistar rats to be supplemented with alpha-lipoic acid and the group that was not to receive alpha-lipoic acid. Nondiabetic rats formed the control group and received a saline injection. In streptozotocin diabetic rats with and without alpha-lipoic acid supplementation, plasma carbonyl levels were significantly increased, while plasma thiol levels were significantly decreased compared with those of the control group. Plasma lipid hydroperoxide levels were significantly increased in diabetic rats without alpha-lipoic acid supplementation compared with those of the controls, but the lipid hydroperoxide levels in the alpha-lipoic acid supplemented group were no different from those of the controls. In streptozotocin-diabetic rats, oxidative stress was significantly decreased in the alpha-lipoic acid-supplemented group. The results of this study suggest that alpha-lipoic acid, by decreasing oxidative stress, may be effective in preventing oxidative protein damage, which may contribute to the development of diabetic complications.

Changes in bone turnover and deoxypyridinoline levels in epileptic patients.

In this study, we evaluated bone turnover in 52 epileptic patients receiving chronic anticonvulsant therapy and in 39 healthy volunteers whose ages matched those of the patients. We determined serum osteocalcin and total and bone alkaline phosphatase levels as markers of bone formation, and urinary deoxypyridinoline and urinary calcium levels as markers of bone resorption. Statistical comparison of the levels of these markers between sexes in epileptic patients and their control groups revealed that total alkaline phosphatase levels were significantly increased in patients from both sexes compared with those of their controls. Urinary deoxypyridinoline levels of male epileptic patients were significantly increased compared with those of their controls. On the other hand, 25-hydroxyvitamin D levels of the male patients were significantly reduced compared with those of their controls. Serum osteocalcin, bone alkaline phosphatase, and urinary calcium levels of epileptic patients were not statistically different from those of the controls. We found that urinary deoxypyridinoline levels of male epileptic patients were increased, however, we observed no difference in serum osteocalcin and bone alkaline phosphatase levels. The lack of difference may be attributed to the fact that only the resorption phase of bone turnover is affected during chronic anticonvulsant therapy.

Oxidative protein damage in plasma of type 2 diabetic patients.

In this study, we evaluated protein oxidation in 84 patients with Type 2 diabetes with no complications and in 61 healthy volunteers who formed the control group, whose ages matched those of the patients. We determined plasma carbonyl and plasma thiol levels as markers of oxidative protein damage and erythrocyte glutathione, plasma ceruloplasmin and transferrin as markers of free radical scavengers. The concentrations (mean +/- SD) of both of plasma carbonyl (1.24 +/- 0.46 vs. 0.72 +/- 0.17 nmole/mg protein; p < 0.0001) and lipid hydroperoxides (1.8 +/- 0.63 vs. 1.3 +/- 0.21 micromole/l; p < 0.0001) were increased, and the concentration of plasma transferrin (3.85 +/- 0.65 vs. 4.59 +/- 0.79 g/l; p < 0.05) was decreased, respectively, in Type 2 diabetic patients compared with those of the controls. There were no significant differences in the concentrations of plasma thiol (0.0064 +/- 0.001 vs. 0.0068 +/- 0.001 micromole/mg protein), erythrocyte glutathione (2.54 +/- 0.57 vs. 2.65 +/- 0.56 mg/g Hb), plasma ceruloplasmin (548 +/- 107.30 vs. 609 +/- 93.34 mg/l) between the patients and the controls. These changes observed in diabetic patients contribute to the imbalance in the redox status of the plasma. We attribute this imbalance to oxidative protein damage in Type 2 diabetic patients clinically free of complications.

Effects of hormone replacement therapy on lipid peroxides and oxidation system in postmenopausal women.

A short-term evaluation of 6 months of estrogen therapy on oxidant status in 38 postmenopausal women was conducted. The levels of serum lipid peroxidation products, glutathione (GSH) status, and glutathione-related enzymes were evaluated before and after 6 months of hormone replacement therapy. After 6 months of estrogen treatment there was a significantly increased concentration of thiobarbituric acid-reactive substances (TBARS), which are an end product of lipid peroxidation. This was accompanied by a significant increase in the activity of glutathione peroxidase (GSH-Px). However, the activities of glutathione reductase (GSSG-R) and superoxide dismutase (SOD) were significantly decreased and total protein thiols were reduced. Data suggest that hormone replacement therapy in postmenopausal women is associated with oxidant mechanisms.

The susceptibility of red blood cells to autoxidation in type 2 diabetic patients with angiopathy.

We examined the in vitro susceptibility of red blood cell (RBC) lipids to oxidation in type 2 diabetic patients with or without angiopathy. Lipid peroxidation was assessed by quantifying thiobarbituric acid (TBA) reactivity as malondialdehyde (MDA). We also examined the RBC antioxidant status by determining glutathione (GSH) levels. Before in vitro oxidation, RBC MDA levels were significantly higher in both diabetic groups than in the controls (P < .001), and a significant difference was found between the two diabetic groups (P < .05). After in vitro treatment of RBCs with hydrogen peroxide, the degree of lipid peroxidative damage was significantly higher in diabetic patients with angiopathy versus diabetics without angiopathy (P < .001). Diabetic patients have low RBC GSH levels compared with controls, and after in vitro oxidation, the levels were significantly decreased in diabetics (P < .001). There was not a significant correlation between RBC MDA levels and glycated hemoglobin (GHb), plasma cholesterol, and triglyceride. The correlation between RBC MDA and GSH was weak (P < .001). We suggest that the results of this study might help to clarify the role of oxidative mechanisms as an in vitro model of degenerative damage in type 2 diabetic angiopathic complications.