Influence of treadmill training on bone structure under osteometabolic alteration in rats subjected to high-fat diet.

Nutrition and physical training have important roles in the accumulation and maintenance of bone mass. The aim of this study was to evaluate, in ovariectomized rats (OVX), the effects of treadmill training (T) with high-fat diet (F) on weight gain and bone tissue properties with eight groups (n = 10) for 12 weeks: OVX SC (OVX, sedentary lifestyle, diet control); OVX SF; OVX TC; OVX TF; SH SC (SHAM, sedentary lifestyle, diet control); SH SF; SH TC; and SH TF. Weekly weight gain and final body composition were assessed. After euthanasia, tibiae were analyzed. The trained animals had higher body weight (P = 0.001), bone mineral density (P < 0.001), and trabecular bone (P < 0.001). The animals with a high-fat diet showed higher global fat (P < 0.001), percentage of global fat (P < 0.001) and deformation at impact (P = 0.031) and reduced tibial bone mineral content (P = 0.036). Physical training improves bone microarchitecture, without presenting an increase in impact resistance, and a high-fat diet increases body fat and impairs bone mineralization.

Creatine Supplementation Increases Total Body Water in Soccer Players: a Deuterium Oxide Dilution Study.

This study aimed to evaluate changes in total body water (TBW) in soccer athletes using a deuterium oxide dilution method and bioelectrical impedance (BIA) formulas after 7 days of creatine supplementation. In a double-blind controlled manner, 13 healthy (under-20) soccer players were divided randomly in 2 supplementation groups: Placebo (Pla, n=6) and creatine supplementation (CR, n=7). Before and after the supplementation period (0.3 g/kg/d during 7 days), TBW was determined by deuterium oxide dilution and BIA methods. 7 days of creatine supplementation lead to a large increase in TBW (2.3±1.0 L) determined by deuterium oxide dilution, and a small but significant increase in total body weight (1.0±0.4 kg) in Cr group compared to Pla. The Pla group did not experience any significant changes in TBW or body weight. Although 5 of 6 BIA equations were sensitive to determine TBW changes induced by creatine supplementation, the Kushner et al. 16 method presented the best concordance levels when compared to deuterium dilution method. In conclusion, 7-days of creatine supplementation increased TBW determined by deuterium oxide dilution or BIA formulas. BIA can be useful to determine TBW changes promoted by creatine supplementation in soccer athletes, with special concern for formula choice.

Frequency and Duration Modulate Anticarcinogenic Effects of a Physical Training in the Colon.

Physical exercise has proven protective against colon carcinogenesis. We sought to clarify whether the frequency and duration of physical training were key factors for its anticarcinogenic effects on the colon. Either sedentary or physically trained male Wistar rats (n=82) were either exposed or not to the carcinogen dimethylhidrazine (DMH). The first protocol investigated whether swimming for 60 min in different frequencies modulates antipreneoplastic effects of physical training. Another protocol then explored whether the duration for training 5 times a week impacts on the development of colon preneoplastic lesions. After 8 weeks, serum and colon samples were collected and analyzed afterwards. Swimming once a week for 60 min did not promote those anticarcinogenic effects found in rats trained 5 times weekly. Such weekly sustained physical training not only decreased the development of colon preneoplastic, but also epithelial proliferation, and subepithelial cyclooxygenase 2 (COX-2) expression. Interestingly, a 5 time per week training for less than 60 min was not as protective against colon carcinogenesis as swimming for 90 min. This 90 min training indeed reduced serum cholesterol and triglycerides levels, as well as colonic lipid peroxidation in carcinogen-exposed rats. Our collective data suggest anticarcinogenic effects of physical exercises are potentially promoted when training 5 times a week for at least 60 min.

Plasma malondialdehyde as biomarker of lipid peroxidation: effects of acute exercise.

The marker most frequently used to indicate the level of lipid peroxidation in the field of exercise and sports is malondialdehyde (MDA), which can be determined by many different techniques. However, there are few studies discussing differences and advantages of the methods for MDA assay in sports science field. The aim of the present study was to compare three techniques for quantification of MDA in plasma of humans subjected to acute exercise. MDA was determined by high performance liquid chromatography (MDA-HPLC), thiobarbituric acid reactive species (MDA-TBARS) and 1-methyl-2-phenylindole (MDA-MP) techniques in the plasma of 8 healthy male soccer athletes before and after acute exercise. Acute exercise significantly increased (P<0.05) plasma MDA concentration determined by MDA-HPLC (18%) and MDA-TBARS (56%) techniques. MDA-MP technique did not reveal significant differences, although it increased 25% after exercise. When correlated to the gold standard (MDA-HPLC), MDA-TBARS and MDA-MP techniques showed weak Lin concordance coefficients and non-significant correlation. Also, MDA-TBARS and MDA-MP techniques overestimated the MDA-HPLC technique by 100 and 122%, respectively. In conclusion, MDA-HPLC and MDA-TBARS are sensitive to detect change in MDA induced by acute exercise. MDA-HPLC is the most suitable technique for accurate detection of MDA in sports and exercise area due to its sensitivity and accuracy.

Oral glutamine dipeptide or oral glutamine free amino acid reduces burned injury progression in rats.

This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino acid form, on the progression of burn injuries in rats. Thirty male Wistar rats were burned with a comb metal plate heated in boiling water (98 °C) for three minutes, creating four rectangular full-thickness burn areas separated by three unburned interspaces (zone of stasis) in both dorsum sides. The animals were randomized into three groups (n=10): saline solution (G1-Control) and treated groups that orally received Glutamine as dipeptide (G2-Dip) or free amino acid (G3-FreeAA). Two and seven days after burn injury, lesions were photographed for unburned interspaces necrosis evolution assessment. Seven days after injury, glutathione seric was measured and histopathological analysis was performed. By photographs, there was a significant reduction in necrosis progression in G3-Free-AA between days two and seven. Histopathological analysis at day 7 showed a significantly higher stasis zone without necrosis and a higher number of fibroblasts in G2-Dip and G3-FreeAA compared with G1-Control. Also, glutathione serum dosage was higher in G2-Dip. The plasmatic glutathione levels were higher in the G2-Dip than the G1-Control, and there was a trend to higher levels in G3-FreeAA. The reduction in histological lesions, greater production of fibroblasts, and greater amounts of glutathione may have benefited the evolution of burn necrosis, which showed greater preservation of interspaces.

Blood and salivary oxidative stress biomarkers following an acute session of resistance exercise in humans.

The aim of the present study was to compare oxidative stress biomarkers determined in blood and saliva before and after acute resistance exercise. 1 week after 1 maximum repetition (1RM) test 11 healthy well-trained males completed a hypertrophy acute session of resistance training including 3 sets of 10 repetitions at 75% of the 1RM, with 90 s rest periods between sets. Venous blood and saliva samples were collected before (pre) and 10 min after (post) the resistance training session. A significant (p<0.05) rise in blood lactate accumulation (pre: 1.6+/-0.4 vs. post: 9.5+/-2.4) was found post-acute resistance training compared with baseline values. Significant increases (p<0.05) in TBARS (42%), AOPP (28%), uric acid (27%) and GSH (14%) were detected post-acute resistance training in relation to pre in blood samples. A significant increase (p<0.05) in uric acid (36%) was found in saliva post-acute resistance training as well as a significant correlation (p<0.05) between uric acid determined in blood and saliva. Statistical analysis did not reveal any other change in the salivary oxidative stress biomarkers. In conclusion, an acute session of resistance exercise induces oxidative stress in plasma of trained men after acute resistance training, which was not found in saliva samples except for uric acid.

Oxidative stress biomarkers response to high intensity interval training and relation to performance in competitive swimmers.

AIM: Aim of the study is to investigate the modulations of oxidative stress biomarkers and some antioxidants induced by high intensity interval training bout and its relation to swimming performance. METHODS: Ten swimmers performed a set of 8 maximal swims along 100 m by style of their specialty, with 10 minute for a rest. The concentration of blood lactate ([Lac]) was determined after each swim. The lactate tolerance index (LTI) was determined by the ratio between [Lac] and the respective times of execution of the 8 swims. The time to complete first 100 m swim at maximum effort (P100) and the international point score (IPS) reached in a specific competition were considered performance parameters. Venous blood was collected before and after the anaerobic training effort. RESULTS: Mean blood lactate concentration in the eight swims was 10.9 ± 1.2 mM. Significant increases were observed for TBARS (pre: 4.1±0.7 ?mol/L; post: 4.9±1.1. ?mol/L), CK (pre: 206.4±170.7 U/L; post: 244.4±176.9. U/L), GSH (pre: 0.52±0.06; post: 0.62±0.05. mM), and ascorbic acid (pre: 0.06±0.02; post: 0.11±0.03. mg/dL) after the anaerobic training bout compared to the values obtained before it. In addition, significant correlations (P < 0.05) were detected between LTI and P100 (r = -0.87) and IPS (r = 0.64) and between variation of ascorbic acid and P100 (r = -0.60). CONCLUSION: Anaerobic training bout proposed induces oxidative stress and cell muscle damage markers as well as modulates some antioxidants of competitive swimmers. The modulation of ascorbic acid seems to play an important role in the performance of these athletes.

Oral glutamine dipeptide or oral glutamine free amino acid reduces burned injury progression in rats

Abstract This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino acid form, on the progression of burn injuries in rats. Thirty male Wistar rats were burned with a comb metal plate heated in boiling water (98 °C) for three minutes, creating four rectangular full-thickness burn areas separated by three unburned interspaces (zone of stasis) in both dorsum sides. The animals were randomized into three groups (n=10): saline solution (G1-Control) and treated groups that orally received Glutamine as dipeptide (G2-Dip) or free amino acid (G3-FreeAA). Two and seven days after burn injury, lesions were photographed for unburned interspaces necrosis evolution assessment. Seven days after injury, glutathione seric was measured and histopathological analysis was performed. By photographs, there was a significant reduction in necrosis progression in G3-Free-AA between days two and seven. Histopathological analysis at day 7 showed a significantly higher stasis zone without necrosis and a higher number of fibroblasts in G2-Dip and G3-FreeAA compared with G1-Control. Also, glutathione serum dosage was higher in G2-Dip. The plasmatic glutathione levels were higher in the G2-Dip than the G1-Control, and there was a trend to higher levels in G3-FreeAA. The reduction in histological lesions, greater production of fibroblasts, and greater amounts of glutathione may have benefited the evolution of burn necrosis, which showed greater preservation of interspaces.

Resumo Este estudo foi realizado para avaliar o efeito da Glutamina, como um dipeptídeo ou forma de aminoácido livre, na progressão de queimaduras em ratos. Trinta ratos Wistar machos foram queimados com um pente de metal aquecido em água fervente (98 °C) por três minutos, criando quatro áreas retangulares queimadas separadas por três interesespaços não queimados (zona de estase) em ambos os lados do dorso. Os animais foram randomizados em três grupos (n = 10): solução salina (G1-Controle) e grupos tratados que receberam glutamina via oral como dipeptídeo (G2-Dip) ou aminoácido livre (G3-FreeAA). Dois e sete dias após a queimadura, as lesões foram fotografadas para avaliação da evolução da necrose entre os espaços não queimados. Sete dias após a lesão, foi dosada a glutationa sérica e realizada análise histopatológica. Pelas fotografias, houve uma redução significativa na progressão da necrose no G3-Free-AA entre os dias dois e sete. A análise histopatológica no dia 7 mostrou uma zona de estase significativamente maior sem necrose e número mais elevado de fibroblastos em G2-Dip e G3-FreeAA em comparação com G1-Controle. Os níveis plasmáticos de glutationa foram maiores no G2-Dip em relação ao G1-Controle, e houve tendência a níveis mais elevados no G3-FreeAA. A redução das lesões histológicas, maior produção de fibroblastos, maior quantidade de glutationa podem ter beneficiado a evolução da necrose da queimadura, que mostrou maior preservação dos interespaços.

Oral glutamine dipeptide or oral glutamine free amino acid reduces burned injury progression in rats / O dipeptídeo de glutamina oral ou aminoácido livre de glutamina oral reduz a progressão da lesão por queimadura em ratos

Abstract This study was carried out to evaluate the effect of Glutamine, as a dipeptide or a free amino acid form, on the progression of burn injuries in rats. Thirty male Wistar rats were burned with a comb metal plate heated in boiling water (98 °C) for three minutes, creating four rectangular full-thickness burn areas separated by three unburned interspaces (zone of stasis) in both dorsum sides. The animals were randomized into three groups (n=10): saline solution (G1-Control) and treated groups that orally received Glutamine as dipeptide (G2-Dip) or free amino acid (G3-FreeAA). Two and seven days after burn injury, lesions were photographed for unburned interspaces necrosis evolution assessment. Seven days after injury, glutathione seric was measured and histopathological analysis was performed. By photographs, there was a significant reduction in necrosis progression in G3-Free-AA between days two and seven. Histopathological analysis at day 7 showed a significantly higher stasis zone without necrosis and a higher number of fibroblasts in G2-Dip and G3-FreeAA compared with G1-Control. Also, glutathione serum dosage was higher in G2-Dip. The plasmatic glutathione levels were higher in the G2-Dip than the G1-Control, and there was a trend to higher levels in G3-FreeAA. The reduction in histological lesions, greater production of fibroblasts, and greater amounts of glutathione may have benefited the evolution of burn necrosis, which showed greater preservation of interspaces.

Resumo Este estudo foi realizado para avaliar o efeito da Glutamina, como um dipeptídeo ou forma de aminoácido livre, na progressão de queimaduras em ratos. Trinta ratos Wistar machos foram queimados com um pente de metal aquecido em água fervente (98 °C) por três minutos, criando quatro áreas retangulares queimadas separadas por três interesespaços não queimados (zona de estase) em ambos os lados do dorso. Os animais foram randomizados em três grupos (n = 10): solução salina (G1-Controle) e grupos tratados que receberam glutamina via oral como dipeptídeo (G2-Dip) ou aminoácido livre (G3-FreeAA). Dois e sete dias após a queimadura, as lesões foram fotografadas para avaliação da evolução da necrose entre os espaços não queimados. Sete dias após a lesão, foi dosada a glutationa sérica e realizada análise histopatológica. Pelas fotografias, houve uma redução significativa na progressão da necrose no G3-Free-AA entre os dias dois e sete. A análise histopatológica no dia 7 mostrou uma zona de estase significativamente maior sem necrose e número mais elevado de fibroblastos em G2-Dip e G3-FreeAA em comparação com G1-Controle. Os níveis plasmáticos de glutationa foram maiores no G2-Dip em relação ao G1-Controle, e houve tendência a níveis mais elevados no G3-FreeAA. A redução das lesões histológicas, maior produção de fibroblastos, maior quantidade de glutationa podem ter beneficiado a evolução da necrose da queimadura, que mostrou maior preservação dos interespaços.

Validation of predictive equations for weight and height using a metric tape.

UNLABELLED: Weight and height measurements are important data for the evaluation of nutritional status but some situations prevent the execution of these measurements in the standard manner, using special equipment or an estimate by predictive equations. Predictive equations of height and weight requiring only a metric tape as an instrument have been recently developed. OBJECTIVE: To validate three predictive equations for weight and two for height by Rabito and evaluating their agreement with the equations proposed by Chumlea. METHODS: The following data were collected: sex, age and anthropometric measurements, ie, weight (kg), height (m), subscapular skinfold (mm), calf (cm), arm (cm) and abdominal (cm) circumferences, arm length (cm), and half span (cm). Data were analyzed statistically using the Lin coefficient to test the agreement between the equations and the St. Laurent coefficient to compare the estimated weight and height values with real values. RESULTS: 100 adults (age 48 +/- 18 years) admitted to the University Hospital (HCFMRP/USP) were evaluated. Equations I: W(kg) = 0.5030 (AC) + 0.5634 (AbC) + 1.3180 (CC) +0.0339 (SSSF) - 43.1560 and II: W (kg) = 0.4808 (AC) + 0.5646 (AbC) +1.3160 (CC) - 42.2450 showed the highest coefficients of agreement for weight and equations IV and V showed the highest coefficients of agreement for height. The St. Laurent coefficient indicated that equations III and V were valid for weight and height, respectively. CONCLUSION: Among the validated equations, the number III W (kg) = 0.5759 (AC) + 0.5263 (AbC) +1.2452 (CC) - 4.8689 (S) - 32.9241 and VH (m) = 63,525 -3,237(S) - 0,06904 (A) + 1,293 (HS) are recommended for height or weight because of their easy use for hospitalized patients and the equations be validated in other situations.

Antioxidant compounds and oxidative stress in female dogs during pregnancy.

Pregnancy is a physiological period during which different metabolic pathways are altered, resulting in greater oxygen consumption and modifications of the consumption of energy substrates, with a consequent greater exposure to oxidative stress. The objective of the present study was to determine and describe the serum profile of some antioxidant biomarkers and of oxidative stress markers during pregnancy in healthy dogs. Twenty nonpregnant (NP) and 20 pregnant (P) female dogs were studied. Serum samples were obtained from the animals during the 1st, 3rd, 5th and 7th weeks of pregnancy or during diestrus for the dosage of antioxidant molecules (vitamin E, vitamin A, zinc and magnesium) and oxidative stress markers (TBARS and carbonyl protein). The results revealed a statistically significant difference (p<0.05) between the P and NP groups during the 3rd and 5th week for vitamins A and E (NP>P), and between the 1st and 3rd week for magnesium (NP>P). The other parameters did not differ between weeks within the same group or between groups. The present study shows that the levels of antioxidant molecules of pregnant dogs differed from that of nonpregnant dogs. These mechanisms may represent a protection against oxidative stress during this period for this species, a fact that definitely deserves further study. Also, the participation of other protective mechanisms and the interference of the fetal-placental unit with oxidative stress are still unknown.

Assessment of indicators of vitamin A status in non-cirrhotic chronic hepatitis C patients.

Subjects with chronic liver disease are susceptible to hypovitaminosis A due to several factors. Therefore, identifying patients with vitamin deficiency and a requirement for vitamin supplementation is important. Most studies assessing vitamin A in the context of hepatic disorders are conducted using cirrhotic patients. A cross-sectional study was conducted in 43 non-cirrhotic patients with chronic hepatitis C to evaluate markers of vitamin A status represented by serum retinol, liver retinol, and serum retinol-binding protein levels. We also performed the relative dose-response test, which provides an indirect estimate of hepatic vitamin A reserves. These vitamin A indicators were assessed according to the stage of liver fibrosis using the METAVIR score and the body mass index. The sample study was predominantly composed of male subjects (63%) with mild liver fibrosis (F1). The relative dose-response test was <20% in all subjects, indicating vitamin A sufficiency. Overweight or obese patients had higher serum retinol levels than those with a normal body mass index (2.6 and 1.9 µmol/L, respectively; P<0.01). Subjects with moderate liver fibrosis (F2) showed lower levels of serum retinol (1.9 vs 2.5 µmol/L, P=0.01) and retinol-binding protein levels compared with those with mild fibrosis (F1) (46.3 vs 67.7 µg/mL, P<0.01). These results suggested an effect of being overweight on serum retinol levels. Furthermore, more advanced stages of liver fibrosis were related to a decrease in serum vitamin A levels.

Detection of vitamin A deficiency in Brazilian preschool children using the serum 30-day dose-response test.

BACKGROUND: Vitamin A deficiency (VAD) is endemic in Brazil and health professionals have difficulty in recognizing its subclinical form. In addition, serum retinol concentrations do not always represent vitamin A status in the organism. OBJECTIVE: To identify VAD in preschool children by the serum 30-day dose-response test (+S30DR) and to examine its potential as a tool for the assessment of vitamin A status in the community. DESIGN: A prospective transverse study in which blood samples were obtained from 188 preschool children for the determination of serum retinol concentrations and the children were submitted to ocular inspection and anthropometric measurements. Information about the presence of diarrhea and/or fever during the 15 days preceding the study was also obtained. The children received an oral dose of 200,000 IU vitamin A immediately after the first blood collection. A second blood sample was obtained 30-45 days after supplementation in order to determine the +S30DR. RESULTS: In all, 74.5% (140/188; 95% confidence interval: 68.3-80.7%) of the children presented +S30DR values indicative of low hepatic reserves. The mean serum retinol concentration was significantly lower before supplementation (0.92 and 1.65 micromol/l, respectively; P < 0.0001). No child presented xerophthalmia; 3.7% (7/188) of the children were malnourished. The presence of fever and/or diarrhea during the 15 days preceding the first blood collection did not affect the +S30DR value. CONCLUSIONS: The prevalence of VAD in the study group was elevated. +S30DR proved to be a good indicator of subclinical VAD in children from an underdeveloped country.

Nutritional assessment of vitamin E in malnourished patients with AIDS.

Malnourished patients with acquired immunodeficiency syndrome (AIDS) may have low serum levels and reduced intake of alpha-tocopherol, mainly in the presence of acute-phase response. The aims of this study were to compare intake and serum levels of alpha-tocopherol between malnourished (MN) and non-malnourished (NMN) AIDS patients and to correlate alpha-tocopherol intake and serum levels. Undernutrition was defined as having a body mass index lower than 18. 5 kg/m(2) or a height-creatinine index lower than 70%. A semiquantitative food frequency questionnaire assessed alpha-tocopherol intake. High-performance liquid chromatography determined vitamin serum levels. The patients were divided into MN (n = 14) and NMN (n = 15) groups. There were no statistical differences in relation to clinical findings between MN and NMN, respectively, including moniliasis (7/14 versus 4/15), neurocryptoccocosis and neurotoxoplasmosis (6/14 versus 6/15), pulmonary tuberculosis (4/14 versus 2/15), and fever (1/14 versus 3/15). MN and NMN groups had similar peripheral blood CD(4) levels (111.4+/-87.1 versus 124.4+/-90.9 cells/mm(3)), and both groups had similar and adequate alpha-tocopherol intake (MN = 50.0+/-11.0 versus NMN = 47.2+/-16.5 mg) and serum levels (MN = 17.8+/-7.2 versus NMN = 19.8+/-6.3 micromol/L). Vitamin E intake and serum levels did not show a significant correlation (r = -0.22, P 0.05). Protein-energy nutrition status and acute-phase response were not factors determining vitamin status among AIDS patients.

Lipid peroxidation in nicotinamide-deficient and nicotinamide-supplemented rats with streptozotocin-induced diabetes.

Reactive oxygen species have been related to the pathogenesis of various diseases, including diabetes mellitus. Nicotinamide has been used for the prevention of the diabetogenic effects of streptozotocin (STZ) in animals. In the present study we assessed the effect of diets with deficient, normal or 17-fold supplemented nicotinamide concentrations on the rate of lipoperoxidation in animals with STZ-induced diabetes. Male Wistar rats were divided into three groups kept on one of the diets for six weeks: DD, diabetic rats on a nicotinamide-deficient diet; DN, diabetic rats on a normal nicotinamide diet; and DS, diabetic rats on a nicotinamide-supplemented diet. During the fourth week of the experiment all animals were fasted for 24 hours and injected into the tail vein with a single STZ dose (40 mg/kg weight). Eight animals from each of the six groups were then sacrificed 24 hours, 1 week and 2 weeks after STZ injection. Mean pancreatic thiobarbituric acid reactive substances (TBARS) (nmol/mg tissue) were significantly lower in the DS group (p < 0.05) compared to the DN and DD groups at 24 hours and during the first week. Hepatic TBARS concentrations (nmol/mg protein) did not differ between groups. Mean hepatic reduced glutathione (GSH) levels were significantly higher (46.76 +/- 12.33 nmol/mg protein) in the DS group compared to the DD (32.90 +/- 6.70) and DN (24.55 +/- 6.41) groups, but only after the 24-hour period. Hepatic vitamin E consumption (microgram/g tissue) was considerable in the groups not supplemented with nicotinamide, whereas vitamin E levels were unchanged in the supplemented group. In contrast, plasma vitamin E levels were decreased in the normal and supplemented groups after 1 and 2 weeks. A higher N-methylnicotinamide excretion (microgram/24 hours) occurred in the supplemented group. We conclude that, after induction of diabetes with STZ, nicotinamide supplementation protected from the damage caused by the toxic action of STZ, promoting lower lipid peroxidation.

Effect of a necrogenic dose of diethylnitrosamine on vitamin E-deficient and vitamin E-supplemented rats.

In order to evaluate the effects of a necrogenic dose of diethylnitrosamine (DEN) on vitamin E-deficient and vitamin E-supplemented rats, a single dose of the drug (200 mg/kg body weight) was injected intraperitoneally at the end of 10 weeks of treatment with the diets. The hepatic necrosis and lipoperoxidation provoked by DEN were evaluated 24, 48, 72 and 120 hours after the injection and were found to be more intense in the deficient group (thiobarbituric acid reactive substances (TBARS): 5.20 +/- 1.48 nmol/mg protein; necrosis volume: 68.99 +/- 8.36%; P < 0.05) during the second period. Also, in the same group and during the same period, mean plasma and hepatic vitamin E concentrations and mean liver glutathione concentration were the lowest detected, suggesting the occurrence of antioxidant consumption due to the toxic action of DEN. In contrast to vitamin E deficiency, which permitted the drug to exert stronger toxic effects, 20-fold supplementation with vitamin E did not provide additional protection against the lipoperoxidation and necrosis provoked by DEN (P < 0.05). The results suggest that other mechanisms in addition to lipoperoxidation provoked by free radicals originating from the metabolism of nitrosamines by the cytochrome P-450-dependent enzymatic system may be involved in the hepatotoxic action of these substances.

beta-carotene inhibits persistent and stimulates remodeling gamma GT-positive preneoplastic lesions during early promotion of hepatocarcinogenesis.

The inhibitory effects of beta-carotene or vitamin A on preneoplastic lesions induced in rats were compared, when specifically administered during early promotion of hepatocarcinogenesis. Initiation was performed by diethylnitrosamine. During the selection/promotion period 2-acetylaminofluorene was administered, and a partial hepatectomy was performed. Afterwards, the rats were divided into 3 groups. To two groups, beta-carotene or vitamin A were given for five weeks. Another group served as control and received corn oil. At the end of the study, beta-carotene reduced the incidence and total number of hepatocyte nodules. Vitamin A rats exhibited a lower number of nodules, but the incidence was 100%. Moreover, beta-carotene reduced the total number of gamma GT-positive preneoplastic lesions, as well as the morphometric parameters of persistent gamma GT-positive lesions. In contrast, morphometric parameters of persistent lesions remained almost unaffected in vitamin A animals. Furthermore, beta-carotene significantly increased the number of remodeling gamma GT-positive preneoplastic lesions. Vitamin A administration, however, resulted only in a small increase in the number of remodeling lesions. These results suggest that the inhibitory effects of beta-carotene during early promotion of hepatocarcinogenesis can be attributed not only to an inhibitory effect on persistent lesions, but also to a striking stimulatory activity on remodeling gamma GT-positive lesions.

Evaluation of oxidative stress in the late postoperative stage of liver transplantation.

INTRODUCTION: Liver transplant recipients are at an increased oxidative stress risk due to pre-existing hepatic impairment, ischemia-reperfusion injury, immunosuppression, and functional graft rejection. This study compared the oxidative status of healthy control subjects, patients with liver cirrhosis on the list for transplantation, and subjects already transplanted for at least 12 months. PATIENTS AND METHODS: Sixty adult male patients, aged between 27 and 67 years, were subdivided into 3 groups: a control group (15 healthy volunteers), a cirrhosis group (15 volunteers), and a transplant group (30 volunteers). Oxidative stress was evaluated by activity of reduced glutathione, malondialdehyde, and vitamin E. RESULTS: There was a significant difference (P < .01) in the plasma concentration of reduced glutathione in the 3 groups, with the lowest values observed in the transplanted group. The malondialdehyde values differed significantly (P < .01) among the 3 groups, with the transplanted group again having the lowest concentrations. The lowest concentrations of vitamin E were observed in patients with cirrhosis compared with control subjects, and there was a significant correlation (P < .05) among the 3 groups. No correlations were found between reduced glutathione and vitamin E or between vitamin E and malondialdehyde. However, there were strong correlations between plasma malondialdehyde and reduced glutathione in the 3 groups: control group, r = 0.9972 and P < .0001; cirrhotic group, r = 0.9765 and P < .0001; and transplanted group, r = 0.8981 and P < .0001. CONCLUSIONS: In the late postoperative stage of liver transplantation, oxidative stress persists but in attenuated form.

Assessment of oxidative status markers and NO bioavailability in hypertensive disorders of pregnancy.

The systemic oxidative status in hypertensives disorders of pregnancy (HDP) and its association with endothelial dysfunction is controversial. In the present study, we evaluated systemic plasma levels of oxidative stress markers (TBARS (thiobarbituric acid-reactive substances) and carbonyl) and total antioxidant status (FRAP (ferric reducing ability of plasma (ferric reducing/antioxidant power) and reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide))), as well as assessed the impact these markers have on nitric oxide (NO) status in healthy pregnant (HP, n=38), gestational hypertensive (GH, n=33) and preeclamptic pregnant women (PE, n=28). We found similar values of TBARS among all groups, and reduced carbonyl levels in HDP between the PE and GH. Conversely, significant increases in plasma activity of antioxidant status were observed in the GH and PE groups compared to the HP group (using both MTT or FRAP method). Importantly, HDP present significantly lower nitrite levels compared to HP women. In Conclusion, our findings show a compensatory antioxidant mechanism against reactive oxygen species (ROS) generation in HDP, which is not associated with nitrite levels restoration.

Validation of a FFQ for estimating ω-3, ω-6 and trans fatty acid intake during pregnancy using mature breast milk and food recalls.

BACKGROUND/OBJECTIVES: To assess the performance of a food frequency questionnaire (FFQ) for estimating ω-3, ω-6 and trans fatty acid intake during pregnancy. Moreover, we determined whether the fatty acid composition of mature breast milk represents a valuable biomarker for fatty acid intake during pregnancy. SUBJECTS/METHODS: A prospective study in 41 pregnant women, aged 18-35 years, was conducted. Food intake during pregnancy was evaluated by three 24-h recalls (24 hR), and 2 FFQ. The fatty acid composition of mature breast milk was determined by gas chromatography. The method of triads and joint classification between quartiles of intake were applied. RESULTS: The FFQ was accurate for estimating docosahexanoic (DHA), linoleic and total ω-6 fatty acids according to validity coefficients. Higher agreements (>70%) into the same or adjacent quartiles between the dietary methods were found for α-linolenic, total ω-3, linoleic and trans fatty acid intake. High validity coefficients for eicosapentanoic (EPA) and DHA acids of human milk were found (0.61 and 0.73, respectively), and the method was adequate for categorizing the intake of α-linolenic, total ω-3 and trans fatty acids compared with FFQ estimates, and for arachidonic acid and trans fatty acids compared with food recall estimates, during pregnancy. CONCLUSIONS: The FFQ was an accurate tool for categorizing α-linolenic, total ω-3 and trans fatty acid intake. According to the validity coefficients observed, the FFQ accurately estimated DHA, linoleic and total ω-6 fatty acids and the composition of mature breast milk was shown to be a suitable biomarker for EPA and DHA fatty acid intake during pregnancy.