In utero exposure to air pollution lowers erythrocyte antioxidant defense and decreases weight in adult mice

In this study, we tested the influence of ambient air pollution on different phases of development of adult mice. With respect to adult weight, the animals that had spent their in utero period exposed to pollution showed less weight gain over their lifetime, as well as lower activity levels of the antioxidant enzymes catalase, superoxide dismutase (SOD) and glutathione peroxidase (GPx). Our study suggests that contact with atmospheric pollutants during the foetal period produces important changes on enzymatic erythrocyte antioxidant defense and weight in adult mice. (C) 2011 Elsevier B.V. All rights reserved.

MET Is Highly Expressed in Advanced Stages of Colorectal Cancer and Indicates Worse Prognosis and Mortality

The aim of the present study was to evaluate by immunohistochemistry the prognostic meaning of the tumor marker MET (hepatocyte growth factor) in patients submitted to surgical resection due to primary colorectal adenocarcinoma. Patients and Methods: A retrospective study was carried out that included 286 consecutive patients with colorectal adenocarcinoma, submitted to surgical resection at Barretos Cancer Hospital, from 1993 to 2002. The histopathological expression of the MET tumor marker was evaluated using an anti-protein monoclonal antibody against MET by the streptavidin-biotin-peroxidase technique. The expression of the tumor marker was semi-quantitative, and the slide samples were independently analyzed by three pathologists unaware of patient clinical and histopathological data. Results: The tumor marker expression was positive in 236 (79%) out of a total of 286 patients. This expression was statistically significantly different between stages I and IV (p=0.004), for overall survival (p=0.009), and for cancer-related mortality rates (p=0.022). However, no association between the tumor marker and recurrence (p=0.89) or disease-free interval (p=0.91) was observed. Conclusion: MET has shown significant expression at advanced stages of the disease, as well as for overall survival and cancer-related mortality rates demonstrating to be a valuable marker for poor prognosis in colorectal cancer patients.

Demonstration of epithelial-mesenchymal transition in kidney - The contribution of a coupled histochemical and immunohistochemical staining with Periodic Acid-Thionin Schiff

Traditional Periodic Acid Schiff has been extensively used, coupled with immunohistochemistry for epithelia or mesenchymal cells, to highlight renal tubular basement membrane (TBM). We recently tried to perform such technique in a 5/6 nephrectomy model of progressive renal fibrosis to demonstrate TBM disruption as an evidence for epithelial-mesenchymal transdifferentiation. Despite excellent basement membrane staining with traditional fuchsin-Periodic Acid Schiff, the interface between epithelial and mesenchymal cells was frequently blurred when revealed with 3`3 diaminobenzidine tetrachloride-peroxidase. Also, it was inadequate when revealed with alkaline phosphatase-fast red. We devised a triple staining method with Periodic Acid-Thionin Schiff to highlight basement membrane in blue, after double immunostaining for epithelium and mesenchymal cells. Blue basement membrane rendered a brisk contrast and highlighted boundaries between epithelial-mesenchymal interfaces. This method was easy to perform and useful to demonstrate the TBM, yield a clear demonstration of the very focal TBM disruption found in this model of progressive renal fibrosis.

Aspirin prevents diabetic oxidative changes in rat lacrimal gland structure and function

The aim of this study is to evaluate whether aspirin reduces Diabetis Mellitus (DM) oxidative damage in the lacrimal gland (LG), and ocular surface (OS). Ten weeks after streptozotocin induced DM and aspirin treatment, LG and OS of rats were compared for tear secretion, hidtology, peroxidase activity, and expression of uncoupling proteins (UCPs). DM reduction of tear secretion was prevented by aspirin (P < 0.01). Alterations of LG morphology and increased numbers of lipofucsin-like inclusions were observed in diabetic but not in aspirin-treated diabetic rats. Peroxidase activity levels were higher and UCP-2 was reduced in DM LG but not in aspirin treated (P = 0.0025 and P < 0.05, respectively). The findings prevented by aspirin indicate a direct inhibitory effect on oxidative pathways in LG and their inflammatory consequences, preserving the LG structure and function against hyperglycemia and/or insulin deficiency damage.

Antioxidant status and biomarkers of oxidative stress in bovine leukemia virus-infected dairy cows

Bovine leukemia virus (BLV) is among the most widespread livestock pathogens in many countries. Despite advances in understanding the pathogenesis of this disease, little is known about the involvement of oxidative stress. Therefore, this study examined the antioxidant status and the markers of oxidative stress in BLV-infected dairy cows. BLV infection was associated with an increase in triacylglycerol levels, a decrease in glutathione peroxidase (GSH-Px) activity and a tendency toward lower superoxide dismutase activity in the infected animals. No significant difference was observed in other markers of oxidative stress (i.e., conjugated dienes, hydroperoxides and malondialdehyde) in the infected animals compared to controls. A novel method for the analysis of oxidative stress, Z-scan based on the measurement of the mean-value of 9 in low density lipoprotein indicated that the infected animals had low-density lipoprotein particles that were slightly less modified than those from the healthy group. Thus, we conclude that BLV infection is associated with a selective decrease in GSH-Px activity without any alteration in the common plasma markers of oxidative stress. (C) 2011 Elsevier B.V. All rights reserved.

Protective action of indole-3-acetic acid on induced hepatocarcinoma in mice

In this study, we report the protective effects of IAA on diethylnitrosamine (DEN)-induced hepatocarcinogenesis. BALB/c mice received daily IAA at 50 (T(50)), 250 (T(250)), and 500 (T(500)) mg K(-1) per body mass by gavage for 15 days. At day 15, animals were administered DEN and sacrificed 4 h later. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were analyzed in sera. In addition., hepatomorphologic alterations, activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR), gene expression of antioxidant enzymes and DNA integrity were evaluated in the liver. IAA administration did not show any alterations in any of the parameters available, except for a reduction of the gene expression for antioxidant enzyrries by 55, 56, 27, and 28% for SOD, CAT, GPx, and GR upon T(500). respectively compared with the control. Several hepatic alterations were observed by DEN exposure. Moreover, IAA administration at 3 doses was shown to provide a total prevention of the active reduction of CAT and GR induced by DEN exposure compared with the control. IAA at T5(00) was shown to give partial protection (87, 71, 57, and 90% for respectively SOD, CAT. GPx. and GR) on the down-regulation of the enzymes induced by DEN and this auxin showed a partial protection (50%) on DEN-induced DNA fragmentation for both parameters when compared to DEN alone. This work showed IAA hepatocarcinogenesis protection for the first time by means of a DEN-protective effect on CAT and GR activity. and by affecting antioxidant gene expression and DNA fragmentation. Copyright (C) 2008 John Wiley & Sons, Ltd.

Effect of diode laser on enzymatic activity of parotid glands of diabetic rats

The aim of this study was to evaluate the effect of laser irradiation (LI) on enzymatic activities of amylase, catalase and peroxidase in the parotid glands (PG) of diabetic and non-diabetic rats. Ninety-six female rats were divided into eight groups: D0; D5; D10; D20 and C0; C5; C10; C20, respectively. Diabetes was induced by administration of streptozotocin and confirmed later by the glycemia results. Twenty-nine (29) days after the induction, the PGs of groups D5 and C5; D10 and C10; D20 and C20, were irradiated with 5 J/cm(2), 10 J/cm(2) and 20 J/cm(2) of laser diode (660 nm/100 mW) respectively. On the following day, the rats were euthanized and the enzymatic activity in the PGs was measured. Diabetic rats that had not been irradiated (group D0) showed higher catalase activity (P < 0.05) than those in group C0 (0.14 +/- 0.02 U/mg protein and 0.10 +/- 0.03 U/mg protein, respectively). However, laser irradiation of 5 J/cm(2) and 20 J/cm(2) decreased the catalase activity of the diabetic groups (D5 and D20) to non-diabetic values (P > 0.05). Based on the results of this study, LI decreased catalase activity in the PGs of diabetic rats.

Laser phototherapy effect on protein metabolism parameters of rat salivary glands

The aim of this study was to evaluate the effects of infrared diode laser phototherapy (LP) on tissues of the submandibular gland (SMG) and parotid gland (PG). Wistar rats were randomly divided into experimental (A and B) and control (C) groups. A diode laser, 808 nm wavelength, in continuous wave mode, was applied to the PG, SMG and sublingual gland in the experimental groups on two consecutive days. The doses were 4 J/cm(2) and 8 J/cm(2), and total energy was 7 J and 14 J, respectively. The power output (500 mW) and power density (277 mW/cm(2)) were the same for both experimental groups. In order to visualize the area irradiated by the infrared laser, we used a red pilot beam (650 nm) with 3 mW maximum power for the experimental groups. For the control group, the red pilot beam was the only device used. The SMG and PG were removed after 1 week of the first irradiation. Total protein concentration, amylase, peroxidase, catalase and lactate dehydrogenase assays were performed, as well as histological analysis. Statistical tests revealed significant increase in the total protein concentration for groups A and B in the parotid glands (P < 0.05). Based on the results of this study, LP altered the total protein concentration in rats` parotid glands.

Diabetes induces metabolic alterations in dental pulp

Diabetes can interfere in tissue nutrition and can impair dental pulp metabolism. This disease causes oxidative stress in cells and tissues. However, little is known about the antioxidant system in the dental pulp of diabetics. Thus, it would be of importance to study this system in this tissue in order to verify possible alterations indicative of oxidative stress. The aim of this study was to evaluate some parameters of antioxidant system of the dental pulp of healthy (n = 8) and diabetic rats (n = 8). Diabetes was induced by streptozotocin in rats. Six weeks after diabetes induction, a pool of the dental pulp of the 4 incisors of each rat (healthy and diabetic) was used for the determination of total protein and sialic acid concentrations and catalase and peroxidase activities. Data were compared by a Student t test (p <= 0.05). Dental pulps from both groups presented similar total protein concentrations and peroxidase activity. Dental pulps of diabetic rats exhibited significantly lower free, conjugated, and total sialic acid concentrations than those of control tissues. Catalase activity in diabetic dental pulps was significantly enhanced in comparison with that of control pulps. The result of the present study is indicative of oxidative stress in the dental pulp caused by diabetes. The increase of catalase activity and the reduction of sialic acid could be resultant of reactive oxygen species production.

Effect of defocused infrared diode laser on salivary flow rate and some salivary parameters of rats

This study aims to investigate whether infrared diode low-level laser therapy (LLLT) increased salivary flow rate and altered pH value, protein concentration, and peroxidase and amylase activities in saliva of rats. Wistar rats were used and divided into three groups. Experimental groups (A and 13) had their parotid, submandibular and sublingual glands submitted to diode laser, 808-nm wavelength, on two consecutive days. The dose results were 4 and 8 J/cm(2), respectively. A red guide light was used to visualize the irradiated area. Group C was irradiated only with red pilot beam and served as control. The saliva samples were collected after each irradiation step (first and second collection days) and 1 week after the first irradiation (seventh day). Statistical analysis was performed, and differences were observed according to different days of salivary collection. The results showed that salivary flow rate for groups A and B was higher on the seventh day if it is compared to data obtained for the first day (p<0.05). LLLT applications on salivary glands are a therapy procedure that requires further studies.

Acid phosphatase and cathepsin D are active expressed enzymes in the placenta of the cat

Enzymes are crucial for the metabolism of macromolecular substrates. In the great majority of cells, most enzymes are constitutive. Nevertheless, inducible enzymes can predominate, determining specialized cell functions. Within this context, histochemistry/immunohistochemistry and biochemistry were used to investigate expression of peroxidase and reduced nicotinamide-adenine dinucleotide phosphate (NADPH)-oxidase, as well as the expression and activity of cathepsin D and acid phosphatase, in trophoblast cells within the endotheliochorial labyrinth and marginal hematoma of the term cat placenta. In the marginal hematoma, elevated Cathepsin D expression and activity was accompanied by erythrophagocytosis. In contrast, acid phosphatase activity was much more intense in the labyrinth, where metabolic exchanges occur. Peroxidase and NAD(P)H-oxidase were predominantly active in trophoblast cells within endosomal vesicles of different placental compartments, indicating that, although reactive oxygen species might participate in endosomal/lysosomal processes, they are not territorially specific or functional markers. These findings highlight differential characteristics of cathepsin D and acid phosphatase activity within each placental compartment, thereby contributing to the comprehension of the territorial role played by the placenta and facilitating future metabolic studies. (C) 2007 Elsevier Ltd. All rights reserved.

Antioxidant enzymatic defense in salivary glands of streptozotocin-induced diabetic rats: a temporal study

Hyperglycemia induces overproduction of superoxide and it is related to diabetic complications. In this study, we analyzed the antioxidant enzymatic defense and the lipid peroxidation of rat salivary glands in six different periods of diabetic condition. Ninety-six rats were divided into 12 groups: C7/14/21128/45/60 (non-diabetic animals) and D7/14/21/28/45/60 (diabetic animals). Diabetes was induced by streptozotocin and the rats were euthanized after 7, 14, 21, 28, 45, or 60 days. Their parotid (PA) and submandibular (SM) glands were removed soon after the sacrifice and the total protein and malondialdehyde (MDA) concentrations, as well as, the superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) activities were determined. Twenty-one days after the diabetes induction, the SM glands showed an increase in SOD, CAT, and GPx activities, as well as, MDA concentration. Concerning the PA glands, an increase in the CAT activity and MDA content was observed throughout the observation period. The results suggest that diabetes can cause alterations on the salivary glands and that PA and SM glands react differently when exposed to diabetes condition. However, no impairment of antioxidant system was observed in the group whose diabetic condition had been induced 60 days earlier, herein named 60-day group. Copyright (C) 2010 John Wiley & Sons, Ltd.

Cytotoxic Effects of Different Concentrations of a Carbamide Peroxide Bleaching Gel on Odontoblast-Like Cells MDPC-23

This study evaluated the cytotoxic effects of a carbamide peroxide (CP) bleaching gel at different concentrations on odontoblast-like cells. Immortalized cells of the MDPC-23 cell line (30,000 cells/cm(2)) were incubated for 48 h. The bleaching gel was diluted in DMEM culture medium originating extracts with different CP concentrations. The amount (mu g/mL) of hydrogen peroxide (H(2)O(2)) released from each extract was measured by the leukocrystal violet/horseradish peroxidase enzyme assay. Five groups (n = 10) were formed according to the CP concentration in the extracts: G1-DMEM (control); G2-0.0001 % CP (0.025 mu g/mL H(2)O(2)); G3-0.001% CP (0.43 mu g/mL H(2)O(2)); G4-0.01% CP (2.21 mu g/mL H(2)O(2)); and G5-0.1 % CP (29.74 mu g/mL H(2)O(2)). MDPC-23 cells were exposed to the bleaching gel extracts for 60 min and cell metabolism was evaluated by the NITT assay. Data were analyzed statistically by one-way ANOVA and Tukey`s test (alpha = 0.05). Cell morphology was examined by scanning electron microscopy. The percentages of viable cells were as follows: G1, 100%; G2, 89.41%; G3, 82.4%; G4, 61.5%; and G5, 23.0%. G2 and G3 did not differ significantly (p > 0.05) from G1. The most severe cytotoxic effects were observed in G3 and G4. In conclusion, even at low concentrations, the CP gel extracts presented cytotoxic effects. This cytotoxicity was dose-dependent, and the 0.1% CP concentration caused the most intense cytopathic effects to the MDPC-23 cells. (C) 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 9013: 907-912, 2009

Effects of molecular crowding by saccharides on alpha-chymotrypsin dimerization

Given the importance of protein complexes as therapeutic targets, it is necessary to understand the physical chemistry of these interactions under the crowded conditions that exist in cells. We have used sedimentation equilibrium to quantify the enhancement of the reversible homodimerization of alpha-chymotrypsin by high concentrations of the osmolytes glucose, sucrose, and raffinose. In an attempt to rationalize the ostuolyte-mediated stabilization of the a-chymotrypsin homodimer, we have used models based on binding interactions (transfer-free energy analysis) and steric interactions (excluded volume theory) to predict the stabilization. Although transfer-free energy analysis predicts reasonably well the relatively small stabilization observed for complex formation between cytochrome c and cytochrome c peroxidase, as well as that between bobtail quail lysozyme and a monoclonal Fab fragment, it underestimates the sugar-mediated stabilization of the alpha-chymotrypsin dimer. Although predictions based on excluded volume theory overestimate the stabilization, it would seem that a major determinant in the observed stabilization of the a-chymotrypsin homodimer is the thermodynamic nonideality arising from molecular crowding by the three small sugars.

Effects of vitamin E deficiency on fatigue and muscle contractile properties

Radical-mediated oxidative damage of skeletal muscle membranes has been implicated in the fatigue process. Vitamin E (VE) is a major chain breaking antioxidant that has been shown to reduce contraction-mediated oxidative damage. We hypothesized that VE deficiency would adversely affect Muscle contractile function, resulting in a more rapid development of muscular fatigue during exercise. To test this postulate, rats were fed either a VE-deficient (EDEF) diet or a control (CON) diet containing VE. Following a 12-week feeding period, animals were anesthetized and mechanically ventilated. Muscle endurance (fatigue) and contractile properties were evaluated using an in situ preparation of the tibialis anterior (TA) muscle. Contractile properties of the TA muscle were determined before and after a fatigue protocol. The muscle fatigue protocol consisted of 60 min of repetitive contractions (250 ms trains at 15 Hz; duty cycle = I I %) of the TA muscle. Prior to the fatigue protocol, no significant differences existed in the force-frequency curves between EDEF and CON animals. At the completion of the fatigue protocol, muscular force production was significantly (P