A moderate intensity exercise program improves physical function and oxidative damage in older women with and without sarcopenic obesity.

BACKGROUND AND OBJECTIVES: The excess of body fat and muscle mass loss in adulthood results in sarcopenic obesity, which is associated with disability and poor physical condition. A relationship among obesity, sarcopenia and oxidative stress also has been established. These aspects limit a good muscle function which is crucial in the independence of older women with and without sarcopenic obesity. This study had as objective to design a moderate intensity exercise program for older women with sarcopenic obesity, and to examine its effects on oxidative damage and physical function. We hypothesized that the exercise program will reduce oxidative damage and to improve the physical function of older women with sarcopenic obesity. METHODS: Thirty healthy women (68 ± 5.05 years old) and 30 women with sarcopenic obesity (68.06 ± 5.75 years old) from the Integral Development of the Family rest home participated in the evaluation. The participants underwent evaluations of body composition, physical fitness (timed up-and-go [TUG] test, reaction time, gait speed, flexibility and muscle strength) and oxidative stress (oxidative damage to lipid and protein as well as evaluation of the antioxidant system) before and after of moderate intensity exercise program. The program consisted of warm-up, flexibility; aerobic exercises of moderate intensity (VO2 max and HR max between 60% and 70%); isotonic exercises of low intensity with progressive weight (250 g of initial weight, with increase every two weeks until reaching 750 g of final weight) and global stretching at the end of each section. The program was monitored on a personal basis and undertaken three times a week over three months. RESULTS: In both groups, the program induced a five-fold increase in muscle strength, an increase in flexibility and improvement of fragility parameters (TUG and gait speed) (P ≤ 0.001, respectively). Furthermore, this exercise program decreased oxidative damage and increased antioxidant defense (P ≤ 0.001) to a greater extent in the sarcopenic group. CONCLUSION: It was concluded that moderate intensity exercise is an effective approach to promote changes in body composition, physical fitness and to reduce oxidative damage in older women with and without sarcopenic obesity. These findings might have important implications for the prevention or treatment of sarcopenic obesity in older people.

Characterization of Oxidative Stress and Ammonia According to the Different Grades of Hepatic Encephalopathy.

BACKGROUND: Hepatic encephalopathy (HE) in patients with chronic liver disease (CLD) is one of the main causes of reentry to the emergency department. Oxidative stress (OxS) regulated by ammonia leads to cerebral edema and astrocytes senescence in animal models, but seems to be different in humans. OBJECTIVE: To analyze if OxS and ammonia in plasma are related to each other in the different grades of HE-CLD and to compare them with healthy volunteers (HV). METHODS: In a cross-sectional study, we included 60 subjects in 2 groups: (a) 30 HV and (b) 30 HE patients. Plasma levels of oxidation lipids/proteins, ammonia, and West-Haven score were evaluated. Student t test, Spearman's correlation, and ANOVA with Dunn's post hoc test were performed. RESULTS: Ammonia in HV and HE patients was 39-49 vs. 95-345 µmol/L, respectively (p < 0.0001). Malondialdehyde (MDA) in HV was 6.58 ± 3.11 compared to 16.69 ± 6.19 µmol/L in HE (p < 0.0001). Protein oxidation by osazone (carbonyls), formazan, and dityrosines was higher in HE than in HV (p < 0.0001). Ammonia level was directly associated to HE severity, but without correlation with lipid MDA or protein OxS formazan, carbonyls, and dityrosines. Lipid peroxidation showed higher levels at degree 2 and protein oxidation at degree 3 of HE. CONCLUSIONS: We confirm that OxS accompanies hyperammonemia in HE; however they contribute in different proportions to their natural progression. Early reduction of OxS in HE could contribute to minimize the neurotoxicity into CLD.

Impact of intestinal mannitol on hyperammonemia, oxidative stress and severity of hepatic encephalopathy in the ED.

Hyperammonemia results from hepatic inability to remove nitrogenous products generated by protein metabolism of intestinal microbiota, which leads to hepatic encephalopathy (HE) in chronic liver disease (CLD). In ammonium neurotoxicity, oxidative stress (OxS) plays a pathogenic role. Our objective was to evaluate if intestinal mannitol is as effective and safe as conventional treatment for diminishing hyperammonemia, OxS, and HE in patients with CLD. MATERIAL AND METHODS: We included 30 patients with HE classified by "Haven Criteria for Hepatic Encephalopathy". They were randomized into two groups: 1) Mannitol Group (MG) with mannitol 20% administered into the intestine by an enema, 2) conventional group (CG) with lactulose 40 g enema both substances were diluted in 800 mL of double distilled solution every 6 h; all patients received neomycin. We evaluated ammonia concentration, plasma oxidative stress, HE severity, intestinal discomfort and adverse effects. RESULTS: Hyperammonemia (171 ±â€¯104 vs 79 ±â€¯49 µmol ammonia/L, p < 0.01), and oxidative stress (MDA 29 vs 27%, formazan 15 vs 11%, carbonyls 16 vs 9% and dityrosines 10 vs 5%) were reduced in MG and CG respectively. The HE severity decreased by two degrees compared to baseline values in both groups. Intestinal discomfort and electrolyte plasma alterations were less frequent (p < 0.05) in MG than CG. CONCLUSIONS: Intestinal mannitol is as effective and safe as conventional treatment for reducing hyperammonemia, oxidative stress, and hepatic encephalopathy of CLD patients in the emergency room. Likewise, mannitol is better tolerated than conventional treatment.

Preeclampsia is associated with ACE I/D polymorphism, obesity and oxidative damage in Mexican women.

OBJECTIVE: This study sought to determine whether the angiotensin-converting enzyme insertion/deletion (ACE I/D) polymorphism, obesity and oxidative damage are risk factors for the development of preeclampsia in Mexican women. STUDY DESIGN: A total of 66 women with preeclampsia (PE) and 37 women with normal pregnancies (NP) were included in the study. DNA was extracted from whole blood, and the ACE I/D polymorphism was evaluated by polymerase chain reaction. ACE activity and oxidative damage were assessed in plasma. The intergroup comparisons were analyzed by an analysis of variance (ANOVA) with post hoc tests. Hardy-Weinberg equilibrium (HWE) was tested by x2 analysis, odds ratios (OR) were calculated as a measure of the degree of relative risk of preeclampsia, and for correlations, we used Spearman's correlation coefficient. RESULTS: The frequency of the DD genotype was higher in PE (34.84%) than NP (10.82%). The OR of the DD genotype and D allele were associated with a 4.4-fold (CI=95% 2.24-14) and 3-fold (CI=95% 1.69-5.62) increased risk of developing PE, respectively. Major ACE activity in the DD genotype and obesity were features of the PE group; oxidative damage to proteins and a reduction in the activity of the antioxidant system showed a correlation with BMI (p<0.01). CONCLUSION: Our results suggest that ACE I/D polymorphism, high ACE activity, body mass index and oxidative damage may play key roles in the pathogenesis of PE in the Mexican population. Furthermore, these findings could be used as predictive factors of PE.

An association of cocoa consumption with improved physical fitness and decreased muscle damage and oxidative stress in athletes.

BACKGROUND: Several studies have demonstrated the protective effects of cocoa consumption, due to its anti-inflammatory and antioxidant properties. Acute exercise induces oxidative stress and causes muscular damage during training. This study was designed to examine the effect of cocoa consumption on the markers of muscle damage, oxidative stress and physical fitness in professional soccer players. METHODS: Fifteen players (15-18 years old) were included in the study. Biochemical parameters, markers of muscle damage and oxidative stress, and physical performance were evaluated before and after cocoa consumption. Biochemical parameters determined the healthy metabolic status of the study group; biomarkers of muscle and oxidative damage were measured in blood to establish muscle and redox status. RESULTS: However, high levels of biomarkers of muscle damage were detected. Interestingly, cocoa consumption decreased the muscle damage biomarkers of CK and LDH by 39.4% and 23.03%, respectively. The redox status was modified by a decrease in oxidative damage (carbonyl groups, 26.31%; thiol groups, 27.52%; MDA, 32.42%) and an increase in total antioxidant capacity (15.98%) and GSH-Px activity (26.37%). In addition, we observed an increase in physical performance by 4% in the Cooper Test. CONCLUSIONS: Our findings suggest that a short period of cocoa consumption could be useful in maintaining a good physical fitness, due to the favourable effects on muscle and redox status in athletes during exhaustive exercise.

The association of subtypes of breast cancer with tumour characteristics and reproductive factors in 1326 Mexican women.

AIM OF THE STUDY: In breast cancer, oestrogen receptor (ER), progesterone receptor (PgR), and HER2 (HER2/Neu) expression status are used to classify neoplasms into subtypes: Luminal A, Luminal B, HER2/Neu type, and Basallike. The aim of the present study was to establish the molecular subtypes of breast cancers and their association with tumour characteristics and reproductive factors in Mexican women. MATERIAL AND METHODS: A total of 1326 biopsies of breast tumour tissues were analysed for ER, PR, and HER2/Neu by immunohistochemistry (IHC). Information regarding age, tumour characteristics, and node involvement profiles were collected. RESULTS: IHC established that the most common subtype of breast cancer was Luminal A (64.93%), followed by Basal-Like (13.88%), Luminal B (12.52%), and HER2/Neu (8.67%). T2-size tumours (> 2 cm but < 5 cm) were present in 47.59% of all patients. Univariate analysis showed that lymph node positivity (p = 0.009), stage (p = 0.013), and placement of the tumour (p = 0.001) were factors associated with breast cancer subtype. CONCLUSIONS: Our data show that IHC is useful for distinguishing different subtypes of breast cancer and that Luminal A is the most common breast cancer subtype in the Mexican population. All subtypes were associated with unfavourable clinicopathological features, suggesting that late diagnosis is an important contributor to high mortality rates in the Mexican population.

Anthropometric traits, blood pressure, and dietary and physical exercise habits in health sciences students; the obesity observatory project.

BACKGROUND: Obesity and the metabolic syndrome affect a considerable segment of the population worldwide, including health professionals. In fact, several studies have reported that physicians tend to have more cardiovascular risk factors than their patients. The present cross-sectional study assessed whether the Health Sciences students had a healthier lifestyle, thus could have a more preventive attitude towards chronic diseases than the general population. MATERIALS AND METHODS: Students of the medical-biological areas were surveyed by answering a questionnaire about familiar cardiovascular risk factors, personal smoking, alcohol drinking, dietary and exercise habits. Blood pressure was also measured, along with weight, height, and abdominal circumference. RESULTS: 23.4% of the participants were overweight and 10% obese. Parental obesity was the most frequent risk factor, followed by social drinking and smoking. We found high consumption of animal derived foods, breakfast- like cereals, pastries, white bread and sweetened beverages; while low intake of fruit and vegetables were reported. More than half the sample reported to practice very little or no exercise at all. DISCUSSION AND CONCLUSIONS: We found similar or even higher rates of risk factors than the average population, that may eventually lead to the development of chronic cardiometabolic diseases. Thus we can infer that biomedical education is inefficient in inducing healthy lifestyles among biomedical students, which could have impact in their future practice as they will most probable become obese health-professionals, thus fail to effectively treat their own patients.

Introducción: La obesidad y el síndrome metabólico afectan a un segmento considerable de la población mundial, incluyendo a los profesionales de la salud. De hecho, diversos estudios han reportado que los médicos tienden a presentar más factores de riesgo cardiovascular que sus propios pacientes. El presente estudio transversal evaluó si los estudiantes del área de la salud tenían un estilo de vida más saludable y, por tanto, una mejor actitud en cuanto a la prevención de las enfermedades crónico-degenerativas, que el resto de la población. Materiales y métodos: Se encuestaron estudiantes del área medico-biológica a través de un cuestionario sobre antecedentes heredo-familiares de riesgo cardiovascular, consumo actual de tabaco y alcohol, así como hábitos alimentarios y de ejercicio físico. Se midió la presión arterial, el peos, la talla y la circunferencia abdominal. Resultados: 23.4% de los participantes presentaban sobrepeso y 10% obesidad. La obesidad paterna fue el factor de riesgo más frecuente, seguido de consumo social de alcohol y tabaquismo. Se encontró un alto consume de alimentos de origen animal, cereales industrializados y refrescos; por otra parte, se reportó un bajo consumo de verduras y frutas. Más de la mitad de la muestra refirió ser sedentario. Discusión y conclusiones: Se encontraron datos muy similares a aquéllos reportados sobre la población general, que eventualmente conducirán al desarrollo de enfermedades cardiometabólicas. Por tanto, es posible inferir que la educación biomédica no es eficiente en la inducción de un estilo de vida saludable entre los estudiantes de ciencias de la salud. Tal fenómeno podría impactar su práctica futura ya que probablemente se convertirán en profesionistas obesos, con la consecuente falla en la prevención primaria y secundaria de sus propios pacientes.

Anthropometric traits, blood pressure, and dietary and physical exercise habits in health sciences students: the Obesity Observatory Project / Características antropométricas, presión arterial, hábitos dietarios y de actividad física en estudiantes de ciencias de la salud; el Proyecto Observatorio de Obesidad

Background: Obesity and the metabolic syndrome affect a considerable segment of the population worldwide, including health professionals. In fact, several studies have reported that physicians tend to have more cardiovascular risk factors than their patients. The present cross-sectional study assessed whether the Health Sciences students had a healthier lifestyle, thus could have a more preventive attitude towards chronic diseases than the general population. Materials and methods: Students of the medical-biological areas were surveyed by answering a questionnaire about familiar cardiovascular risk factors, personal smoking, alcohol drinking, dietary and exercise habits. Blood pressure was also measured, along with weight, height, and abdominal circumference. Results: 23.4% of the participants were overweight and 10% obese. Parental obesity was the most frequent risk factor, followed by social drinking and smoking. We found high consumption of animal derived foods, breakfast-like cereals, pastries, white bread and sweetened beverages; while low intake of fruit and vegetables were reported. More than half the sample reported to practice very little or no exercise at all. Discussion and conclusions: We found similar or even higher rates of risk factors than the average population, that may eventually lead to the development of chronic cardiometabolic diseases. Thus we can infer that biomedical education is inefficient in inducing healthy lifestyles among biomedical students, which could have impact in their future practice as they will most probable become obese health-professionals, thus fail to effectively treat their own patients (AU)

Introducción: La obesidad y el síndrome metabólico afectan a un segmento considerable de la población mundial, incluyendo a los profesionales de la salud. De hecho, diversos estudios han reportado que los médicos tienden a presentar más factores de riesgo cardiovascular que sus propios pacientes. El presente estudio transversal evaluó si los estudiantes del área de la salud tenían un estilo de vida más saludable y, por tanto, una mejor actitud en cuanto a la prevención de las enfermedades crónico-degenerativas, que el resto de la población. Materiales y métodos: Se encuestaron estudiantes del área medico-biológica a través de un cuestionario sobre antecedentes heredo-familiares de riesgo cardiovascular, consumo actual de tabaco y alcohol, así como hábitos alimentarios y de ejercicio físico. Se midió la presión arterial, el peos, la talla y la circunferencia abdominal. Resultados: 23.4% de los participantes presentaban sobrepeso y 10% obesidad. La obesidad paterna fue el factor de riesgo más frecuente, seguido de consumo social de alcohol y tabaquismo. Se encontró un alto consume de alimentos de origen animal, cereales industrializados y refrescos; por otra parte, se reportó un bajo consumo de verduras y frutas. Más de la mitad de la muestra refirió ser sedentario. Discusión y conclusiones: Se encontraron datos muy similares a aquéllos reportados sobre la población general, que eventualmente conducirán al desarrollo de enfermedades cardiometabólicas. Por tanto, es posible inferir que la educación biomédica no es eficiente en la inducción de un estilo de vida saludable entre los estudiantes de ciencias de la salud. Tal fenómeno podría impactar su práctica futura ya que probablemente se convertirán en profesionistas obesos, con la consecuente falla en la prevención primaria y secundaria de sus propios pacientes (AU)

Hypocaloric diet and regular moderate aerobic exercise is an effective strategy to reduce anthropometric parameters and oxidative stress in obese patients.

BACKGROUND: Studies show that diet and exercise are important in the treatment of obesity. The aim of this study was to determine whether additional regular moderate aerobic exercise during a treatment with hypocaloric diet has a beneficial effect on oxidative stress and molecular damage in the obese patient. METHODS: Oxidative stress of 16 normal-weight (NW) and 32 obese 1 (O1) subjects (BMI 30-34.9 kg/m(2)) were established by biomarkers of oxidative stress in plasma. Recombinant human insulin was incubated with blood from NW or O1 subjects, and the molecular damage to the hormone was analyzed. Two groups of treatment, hypocaloric diet (HD) and hypocaloric diet plus regular moderate aerobic exercise (HDMAE), were formed, and their effects in obese subjects were analyzed. RESULTS: The data showed the presence of oxidative stress in O1 subjects. Molecular damage and polymerization of insulin was observed more frequently in the blood from O1 subjects. The treatment of O1 subjects with HD decreased the anthropometric parameters as well as oxidative stress and molecular damage, which was more effectively prevented by the treatment with HDMAE. CONCLUSION: HD and HDMAE treatments decreased anthropometric parameters, oxidative stress, and molecular damage in O1 subjects.

Chemical and functional changes of human insulin by in vitro incubation with blood from diabetic patients in oxidative stress.

Oxidative stress damage to biomolecules has been implicated in several diseases including diabetes mellitus. In the present study, we investigated the effect of oxidative stress in whole blood (WB) from diabetic patients (n = 60) on recombinant human insulin. Insulin was incubated with WB obtained from diabetic patients (DP) who had hyperglycemia (>300 mg/dL) or from 41 healthy volunteers (HV). Whole blood of DP, unlike WB of HV, induced higher values of formazan (142%), dityrosines (279%), and carbonyls (58%) in the insulin residues. Interestingly, the insulin modified by WB of DP showed less hypoglycemic activity in rat (30%) in comparison with insulin incubated with WB of HV. The incubation of insulin in WB from DP induces chemical changes in insulin and a decrease in its biological activity, events that might be associated with the high levels of oxidative stress markers found in the plasma of these patients.

Correlation of Plasma Protein Carbonyls and C-Reactive Protein with GOLD Stage Progression in COPD Patients.

Oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). To investigate the correlation between the progression of COPD and plasma biomarkers of chronic inflammation and oxidative injury, blood samples were obtained from healthy volunteers (HV, n = 14) and stabilized COPD patients. The patients were divided into three groups according to their GOLD stage (II, n = 34; III, n = 18; IV, n = 20). C-reactive protein (CRP), protein carbonyls (PC), malondialdehyde (MDA), susceptible lipoperoxidation of plasma substrates (SLPS), and myeloperoxidase activity (MPO) were measured. The plasma concentration of SLPS was measured as the amount of MDA generated by a metal ion-catalyzed reaction in vitro. PC, SLPS, and CPR were increased significantly (p < 0.001) in COPD patients when compared to HV. MDA concentrations and MPO activities were not significantly different from those of the HV group. In conclusion, increased oxidation of lipids and proteins resulting in a progressive increase in the amount of total plasma carbonyls and oxidative stress the presence of oxidative stress during COPD progression, concomitant with an increased oxidation of lipids and proteins resulting in a progressive and significant increase in the amount of total carbonyls formed from lipid-derived aldehydes and direct amino acid side chain oxidation in plasma, may serve as a biomarker and independent monitor of COPD progression and oxidative stress injury.

Formation of an adduct between insulin and the toxic lipoperoxidation product acrolein decreases both the hypoglycemic effect of the hormone in rat and glucose uptake in 3T3 adipocytes.

Lipid peroxidation induced by reactive oxygen species might modify circulating biomolecules because of the formation of alpha,beta-unsaturated or dicarbonylic aldehydes. In order to investigate the interaction between a lipoperoxidation product, acrolein, and a circulating protein, insulin, the acrolein-insulin adduct was obtained. To characterize the adduct, gel filtration chromatography, sodium dodecylsulfate-polyacrylamide gel electrophoresis and carbonyl determination were performed. Induction of hypoglycemia in the rat and stimulation of glucose uptake by 3T3 adipocytes were used to evaluate the biological efficiency of the adduct compared with that of native insulin (Mackness, B., Quarck, R., Verte, W., Mackness, M., and Holvoet, P. (2006) Arterioscler., Thromb. Vasc. Biol. 26, 1545-1550). Formation of the acrolein-insulin complex in vitro increased the carbonyl group concentration from 2.5 to 22.5 nmol/mg of protein, and it formed without intermolecular aggregates (Halliwell, B., and Whiteman, M. (2004) Br. J. Pharmacol. 142, 231-255. The hypoglycaemic effect 18 min after administration to the rat is decreased by 25% (Robertson, R. P. (2004) J. Biol. Chem. 279, 42351-42354. An adduct concentration of 94 nM, compared to 10 nM for native insulin, was required to obtain the A 50% (concentration needed to obtain 50% of maximum transport of glucose uptake by 3T3 adipocytes). In conclusion, formation of the acrolein-insulin adduct modifies the structure of insulin and decreases its hypoglycemic effect in rat and glucose uptake by 3T3 adipocytes. These results help explain how a toxic aldehyde prone to be produced in vivo can structurally modify insulin and change its biological action.

Antioxidants decrease reperfusion induced arrhythmias in myocardial infarction with ST-elevation.

In myocardial infarctions with ST-segment elevation, ischemia followed by reperfusion (IR) leads to arrhythmia, myocardial stunning and endothelial dysfunction injury by reactive oxygen species (ROS). To determine the impact of ROS, we examined the effect of antioxidant vitamins on biochemical changes and arrhythmias induced by reperfusion before and after therapeutic thrombolysis (Actilyse). As compared with those receiving placebo, in individuals who received antioxidants, there was a significant decrease in premature ventricular beats (100% vs 38%), atrial fibrillation (44% vs 6%), ventricular tachycardia (31% vs 0%), first-degree atrial-ventricular block (44% vs 6%), plasma malondialdehyde at the first hour after initiation of thrombolysis (1.07 +/- 0.10 vs 0.53 +/- 0.10 nmols plasma malondialdehyde/mg protein) and circulating neutrophils after 24 hr after reperfusion. The antioxidant capacity of plasma was increased from 1.89 +/- 0.15 to 3.00 +/- 0.31 units/mg protein and paraoxonase-1 rose from 0.77 +/- 0.08 to 1.27 +/- 0.11 nmol/min/mg protein. These findings suggest that antioxidants might be useful as adjuvants in controlling reperfusion induced arrhythmias following therapeutic alteplase thrombolysis.

Oxidation by reactive oxygen species (ROS) alters the structure of human insulin and decreases the insulin-dependent D-glucose-C14 utilization by human adipose tissue.

The formation of dityrosine of human insulin oxidized by metal-catalyzed oxidation system (H2O2/Cu) was estimated by fluorescent methods. The oxidation of tyrosine and phenylalanine residues present on the insulin molecule was evident after 2 minutes of in vitro oxidation due to the formation of protein-bound dityrosine. The success of oxidative protein modification was followed until available aromatic residues were consumed (60 minutes), measured by their emission at 405 nm. The structural and chemical changes on insulin molecule are related to the loss of biological activity as assessed by measuring the increase of U-14C-glucose utilization by human adipose tissue in a radiorespirometry system. The oxidation of glucose (14CO2 production) of the adipose cells was increased 35 % (301 +/- 119 to 407 +/- 182 cpm/mg in dry weight. P < 0.05) in presence of 0.1 IU and 69 % (301 +/- 119 to 510 +/- 266 cpm/dry weight. P < 0.05) for 1.0 IU of insulin. The recombinant human insulin oxidized for 5 minutes only increased the glucose oxidation by 25 %. In conclusion, these observations show that dityrosine formation and other oxidative chemical changes of insulin due to its in vitro oxidation decrease and can abolish its biological activity.

Reactive oxygen species (ROS) induce chemical and structural changes on human insulin in vitro, including alterations in its immunoreactivity.

Oxidative stress occurs when the production of reactive oxygen species (ROS) exceeds the endogenous antioxidant defense. Peroxidations induced by ROS are the key of chemical and structural modifications of biomolecules including circulating proteins. To elucidate the effect of ROS on circulating proteins and considering the presence of oxidative stress in Diabetes Mellitus, the effects of ROS, in vitro, on human insulin were studied. We utilized the Fenton reaction for free hydroxyl radical (HO*) generation in presence of human recombinant insulin measuring chemical changes on its molecular structure. The induced changes in insulin were: a) significant increase on absorbance (280 nm) due to phenylalanine hydroxylation (0.023 +/- 0.007 to 0.13 +/- 0.07). b) Peroxidation products formed on amino acids side branches (peroxyl and alcohoxyl group); measured as increased capacity of reduce nitroblue of tetrazolium (NBT) to formazan (0.007 +/- 0.007 to 0.06 +/- 0.02). c) Increased concentration of free carbonyl groups (8.8 +/- 8.7 to 45.6 +/- 20.2 pmoles dinitrophenylhidrazones/nmol insulin) with lost of secondary structure, and d) Modification of epithopes decreasing the insulin antigen-antibody reactivity measured as a decrease in insulin concentration by RIA. In conclusion, the radical hydroxyl in vitro is able to induce molecular modifications on insulin.