Predictive effect of thiol/disulfide homeostasis dynamics on early pregnancy viability: A case-control study.

Objective: The main aim of this study was to investigate the differences in maternal serum thiol/disulfide homeostasis among women with abortion imminens (AI), missed abortion (MA), and healthy pregnancies during the first trimester. Materials and Methods: This was a prospective case-control study. This study was conducted on pregnant women who visited the Obstetrics Clinic at University of Health Sciences Turkey, Etlik Zübeyde Hanim Gynecology Training and Research Hospital and were diagnosed with either AI or MA during the 6th to 14th weeks of pregnancy. The participants had a normal pregnancy follow-up, no chronic illnesses, and did not take any multivitamin or antioxidant supplements except for folic acid. The study incorporated 33 pregnant women with AI, 36 with MA, and 40 with normal pregnancies. Age, and body mass index were matched across the three groups. This study used a recently developed automated spectrophotometric technique to quantify thiol/disulfide concentrations. Results: The AI group had considerably elevated levels of total thiol and native thiol (SH) compared with the MA group. Nevertheless, there was no notable disparity observed between the group of healthy pregnancies and the other two groups. Serum disulfide (SS) levels did not exhibit any significant variations among the three groups. Similarly, the ratios of SS/SH, SS/total thiol, and SH/total thiol did not show any significant differences between the groups (p>0.05). Conclusion: Patients with MA had decreased levels of total thiol and SH, which possess antioxidant capabilities, compared to the AI group. A decrease in antioxidant levels in the body may contribute to the etiology of MA. When considering our findings alongside existing literature, it remains inconclusive whether the serum thiol-disulfide ratio can predict a healthy pregnancy or MA following AI. Therefore, it is not yet seen as a promising diagnostic tool for assessing pregnancy viability. Additional investigation is required to establish the influence of dynamic thiol/disulfide homeostasis on early pregnancy loss.

Thiol disulfide homeostasis in ionizing radiation and chemotherapeutic drug exposure.

OBJECTIVE: This study aims to reveal the oxidant and antioxidant status in nurses with chemotheropathic drug exposure and radiology unit workers exposed to ionizing radiation (IR). METHODS: Nineteen radiology unit workers, 14 nurses, and 15 controls were included the study. All of the participants using antioxidants, vitamin supplements, smokers, any therapeutic drugs, and exposed therapeutic or diagnostic X-ray or chemotherapeutic drugs in 12 months were excluded from the study. Total and native thiols, disulfide/native thiol percent ratios (SS/SH), disulfide/total thiol percent ratios, disulfide amounts, and native thiol/total thiol percent ratios, ischemia-modified albumin (IMA) were determined. RESULTS: Disulfide levels, disulfide/total thiol ratio, and disulfide/native thiol ratio of serum samples of both radiology unit workers and nurses were significantly higher and ratio of native thiol/total thiol was lower than the control group. The radiation dose in radiology unit workers was mean±SD: 0.02±0.009, median (min-max): 0.02 (0.001-0.04). Thiol-disulfide homeostasis was disturbed and the balance shifted in the direction of oxidant damage, even at low-dose IR exposure and normal range. CONCLUSION: As far as we know, the current findings first demonstrate an apparent chronic oxidative stress in the subjects who were occupationally exposed to antineoplastic drugs and radiation even if annual radiation exposure dose measurements are normal.

Evaluation of Oxidative Stress by Dynamic Thiol/Disulfide Homeostasis and Ischemia-Modified Albumin Levels in Children with ß-Thalassemia Major.

OBJECTIVE: ß-thalassemia major (ß-TM) is a hemoglobinopathy characterized by reduced or absent ß-globin production. A balance remains between the production of free radicals and suppression of increased levels of reactive oxygen species by the antioxidant system. This study aimed to examine thiol/disulfide homeostasis (TDH) and serum ischemia-modified albumin (IMA) levels to evaluate the oxidant/antioxidant balance in healthy children and persons with ß-TM receiving and not receiving chelation therapy. METHODS: This prospective study was carried out from January to June 2021 among 46 individuals with ß-TM and 35 healthy controls. A spectrophotometric method was used to analyze TDH and IMA concentrations. RESULTS: We found that, compared to controls, native thiol (NT) (P = .048) and total thiol (TT) (P = .027) values were lower in the patient group, whereas disulfide (P < .001), disulfide/native thiol (D/NT) (P = .004), disulfide/total thiol (D/TT) (P = .005), native thiol/total thiol (NT/TT) (P = .004) and IMA (P = .045) values were higher. NT and TT levels were significantly lower in the chelation- group compared to the chelation+ and control groups (P = .002, P = .001). D/NT, D/TT, and NT/TT levels were higher in the chelation+ group than the control group (P = .007), and IMA levels were significantly higher in the chelation+ and chelation- groups compared to the control group (P = .002). The receiver operating characteristic analysis demonstrated that IMA levels were significantly higher in the children with ß-TM not taking regular chelation therapy. CONCLUSION: Thiol/disulfide homeostasis was observed to be weakened in children with ß-TM in our study. Our findings show that when children with ß-TM do not receive regular chelation therapy, their oxidant imbalance worsens.

Evaluation of the effect of chiropractic manipulative treatment on oxidative stress in sacroiliac joint dysfunction.

OBJECTIVES: This study aims to investigate the effect of chiropractic manipulative treatment on sacroiliac joint dysfunction (SIJD) and its relationship to oxidative stress (OXS) parameters. PATIENTS AND METHODS: Thirty-three patients diagnosed with SIJD (20 males, 13 females; mean age 36.3±9.7 years; range, 18 to 60 years) and 30 healthy volunteers (20 males, 10 females; mean age 36.4±12.2 years; range, 20 to 57 years) were included in this cross-sectional, case-control study conducted between February 2017 and September 2017. Manipulation was applied to the patients once a week for a duration of four weeks. The patients were evaluated at pre-treatment and one month after treatment with visual analog scale, SIJD test, and total thiol, native thiol, disulphide, and ischemia-modified albumin (IMA) as OXS indicators. RESULTS: Prior to treatment, we demonstrated that serum native thiol (µmol/L) and total thiol (µmol/L) levels in the patient group were lower compared to control subjects (p=0.03 and p=0.02, respectively). Serum IMA levels were higher in the patient group (p=0.01). There was no change in OXS parameters after manipulative treatment in the patient group. CONCLUSION: Manipulation is useful in SIJD. Thiol/disulphide homeostasis and serum IMA levels may be used to measure the OXS in patients with SIJD.

The thiol-disulphide homeostasis in patients with acute pancreatitis and its relation with other blood parameters.

BACKGROUND: Acute pancreatitis is a common disease seen in emergency departments because of abdominal pain. The present study aims to evaluate the relation between measurements of thiol-disulfide parameters in patients diagnosed with acute pancreatitis and other blood parameters. METHODS: A total of 56 (56%) patients, who were admitted to the emergency department, and 44 (44%) healthy volunteers participated in this study. A total of 100 samples were taken from the participants. Detailed blood samples were taken from the patients at the time of arrival at the hospital. The thiol-disulfide level in serum was examined using a brand new method that was developed by Erel and Neselioglu in the venous blood samples of the patients who were diagnosed with acute pancreatitis during the admission. The data were evaluated in the computer medium. RESULTS: Gallstones were defined as the etiology of AP in 41 patients (73.2%); in one patient, hypertriglyceridemia (1.7%); in four patients, alcohol use (7.1%), and idiopathic 10 patients (17.8%). While the blood thiol levels were low, the disulfide levels were high at a significant level. No statistically significant relations were detected between the amylase, lipase, neutrophil lymphocyte ratio (NLR), which are other blood parameters, and thiol-disulfide balance parameters. CONCLUSION: The disruption of the thiol-disulfide balance may play a role in the pathogenesis of acute pancreatitis. In acute pancreatitis, since the thiol level is decreased in the blood, administration of the complementary therapies for this thiol deficiency may contribute to the treatment of the disease.

The Effects of Bilirubin and Phototherapy on Neonatal Thiol-Disulfide Homeostasis.

OBJECTIVE: To determinate the effects of bilirubin and phototherapy on oxidative stress in newborns. STUDY DESIGN: A case-control study. PLACE AND DURATION OF STUDY: Third level Newborn Intensive Care Unit, Ankara Etlik Zubeyde Hanim Women's Health Teaching and Research Hospital, Turkey, from May to August 2017. METHODOLOGY: Blood samples of 62 term newborns were grouped as control, before and after phototherapy. Total and native thiol, disulfide and ischemia modified albumin values in expressed blood samples were measured. Disulfide-native thiol ratio, disulfide-total thiol ratio and native thiol-total thiol ratio values were computed. RESULTS: Bilirubin levels were positively correlated with native and total thiol levels and negatively correlated with ischemia modified albumin levels (r=0.409 p= 0.001, r= 0.328 p<0.009, r=-0.503 p<0.001). Native and total thiol levels of the control group were lower (p<0.001) and ischemia modified albumin levels were higher than those before and after phototherapy (p<0.001). In jaundiced newborns, native and total thiol values reduced after phototherapy, while IMA levels increased (p=0.001, p<0.001, p<0.001). CONCLUSION: Bilirubin showed antioxidant effect without increasing oxidative stress. Oxidative stress increased after phototherapy. This result was associated with decrease in bilirubin rather than oxidative effect of phototherapy.

The consequence of phototherapy exposure on oxidative stress status of expressed human milk.

OBJECTIVE: There exists evidence that phototherapy can disturb the oxidant/antioxidant balance in favor of oxidants. If phototherapy is continued during tube feeding in preterms, expressed human milk is subjected to phototherapy lights for about 20 min per feeding. We aimed to investigate the effects of phototherapy lights on oxidative/antioxidative status of expressed human milk. STUDY DESIGN: Milk samples of 50 healthy mothers were grouped as control and phototherapy and exposed to 20 min of day-light and phototherapy light, respectively. Total antioxidant capacity (mmol-Trolox equiv/L) and total oxidant status (mmol-H2O2/L) in expressed human milk samples were measured. RESULTS: Levels of antioxidant capacity of the expressed human milks in the phototherapy group were lower than those of the control group [mmol-Trolox equiv/L; median (interquartile-range): 1.30 (0.89-1.65) and 1.77 (1.51-2.06), p: < .001]. Levels of oxidant status were similar in both groups. CONCLUSION: We demonstrated that phototherapy decreased antioxidant capacity of expressed human milk without any alteration in oxidative status. We think that this observation is important for the care of very low birth weighted infants who have limited antioxidant capacity and are vulnerable to oxidative stress. It may be advisable either to turn off the phototherapy or cover the tube and syringe to preserve antioxidant capacity of human milk during simultaneous tube feeding and phototherapy treatment.

Vitamin D supplementation does not improve plasma thiol/disulfide homeostasis.

BACKGROUND: Impairment of thiol/disulfide homeostasis, as well as vitamin D deficiency, are responsible for the pathophysiology of many acute and chronic diseases. This study examined the relationship between thiol/disulfide homeostasis and vitamin D level and supplementation. METHODS: A total of 203 healthy children were included in the study. The participants were divided into four groups according to 25-hydroxyvitamin D (25(OH)D) level: group 1, severe deficiency (<10 ng/mL); group 2, deficiency (10-20 ng/mL); group 3, insufficiency (20-30 ng/mL); and group 4, sufficiency (≥30 ng/mL). Furthermore, group 5 was defined as being on vitamin D supplementation. RESULT: Native thiol was lower in group 5 than in groups 2-4 (P = 0.003). Disulfide was higher in groups 1, 4 and 5 than groups 2 and 3 (P < 0.001). Total thiol was lower in group 5 than in group 4 (P = 0.032). The ratio of native thiol/total thiol was lower in groups 1 and 5 compared with groups 2 and 3, and in group 4 compared with group 3 (P < 0.001). The ratios of disulfide/total thiol and disulfide/native thiol were higher in groups 1 and 5 than in groups 2 and 3 whereas only the disulfide/total thiol ratio was higher in group 4 than in group 3 (P < 0.001). CONCLUSIONS: In healthy children, severe deficiency of vitamin D causes impairment of thiol/disulfide homeostasis and increases protein oxidation, which cannot be reversed by external vitamin D supplementation.

A new oxidative stress marker for thiol-disulphide homeostasis in seasonal allergic rhinitis.

BACKGROUND: Reactive oxygen species has a crucial role in the pathogenesis of many diseases. Reactive oxygen species has been effectively documented in patients with asthma, but very little research has been reported in subjects with allergic rhinitis. OBJECTIVES: To investigate thiol (SH)-disulfide (SS) homeostasis, a new oxidative stress marker present in patients with seasonal allergic rhinitis (SAR). METHODS: A total of 64 subjects, including 32 patients with SAR and 32 healthy controls, were included in the study. We measured the SH levels as a marker of antioxidant protection and SS as a marker related to oxidant stress. Sera specimens were taken from patients with SAR during exacerbation and during asymptomatic time periods. In addition, sera samples from the control group were also obtained during the pollen season to compare with those from patients with SAR. RESULTS: In patients with SAR, during exacerbation periods, SH, SS, % SS/SH, % SS to total SH (TT), and % SH/TT were significantly different (p < 0.05) than in patients with SAR during asymptomatic periods. Although SS was significantly higher in patents with SAR during exacerbation periods, SH was significantly higher in patients with SAR during asymptomatic periods. Patients with SAR during asymptomatic periods and the control group did not significantly differ (p > 0.05) regarding SH, SS, TT, % SS/SH, % SS/TT, and % SH/TT. CONCLUSION: SAR is a disorder that elevates systemic oxidative stress and reduces antioxidant enzyme activities. Our results shed light on the etiopathogenesis of the disease and can help develop new therapeutic approaches.

Antioxidant capacity of fresh and stored breast milk: is -80°C optimal temperature for freeze storage?

OBJECTIVE: To determine total antioxidant capacity and total oxidation status in fresh and freeze stored (at -80°C) breast milk during the stages of lactation. METHODS: Samples of colostrum, transitional and mature milk were collected from 44 healthy women at 3, 8 and 30 days after birth. The total milk volume collected (6 ml) was divided in two aliquot parts: 3 ml for the fresh analysis which was done immediately after the extraction and 3 ml for storage under freezing conditions at -80°C for two months. The antioxidant status and oxidative stress of the fresh and stored breast milk were assessed via determination of total antioxidant capacity and total oxidation status. RESULTS: Antioxidant capacity of transitional and mature milk decreased (p = 0.0001, p = 0.028, respectively); however, antioxidant capacity of colostrum did not change by storage at -80°C (p > 0.05). Total antioxidant capacity of fresh and stored breast milk significantly decreased during the stages of lactation (p < 0.0001, p = 0.028, respectively). Total oxidation status showed no significant difference in fresh and stored breast milk during the stages of lactation (p > 0.05). CONCLUSION: Freeze storage of breast milk at -80°C for two months seems not to be the optimal condition to preserve the antioxidant capacity of breast milk.

Evaluation of oxidant and antioxidant status in infants with hyperbilirubinemia and kernicterus.

OBJECTIVE: The objective of the present study was to determine oxidant and antioxidant status in infants with hyperbilirubinemia and/or kernicterus and to find whether there is a relationship between bilirubin level and oxidant/antioxidant status. PATIENTS: The study includes 69 full-term newborns (neonates with hyperbilirubinemia needing phototherapy [Group 1, n = 36] and neonates with kernicterus [Group 2, n = 33]) and 25 age-matched healthy newborn. RESULTS: Plasma total antioxidant capacity (TAC) and serum total oxidant status (TOS) were significantly higher in Groups 1 and 2 than the control group. There was a significant difference between Group 1 and control cases for malondialdehyde (MDA; p < 0.001). Total free sulfhydryl group (TTHI) values were significantly elevated in Group 1 compared to Group 2 and control cases. Correlation analysis showed that the correlation between total bilirubin (TB) and TAC, TOS, MDA and oxidative stress index may be expressed by a quadratic curve. After phototherapy, a statistically significant increase in nitrite level was observed. CONCLUSION: We demonstrated that the relationship between serum TB and antioxidants and oxidative stress could be expressed by a quadratic correlation curve.

Oxidative stress increases in carbon monoxide poisoning patients.

OBJECTIVE: Carbon monoxide poisoning (COP) is one of the important causes of morbidity and mortality in toxicological cases. In this study, we aimed to find out more about the pathophysiology of COP by investigating the effects of COP on oxidative stress parameters such as total oxidant status (TOS) and total antioxidant status (TAS). METHODS: Eighty-eight patients admitted to the emergency department of our hospital with acute COP and 35 healthy adults as control group were included in this study. Blood samples were collected from all COP patients at the time of initial emergency department evaluation to determine the oxidative stress parameters. Then, serum levels of total antioxidant status and total oxidant status levels were measured. RESULTS: A total of 88 patients poisoned by carbon monoxide (CO; mean age 37.1 ± 18.2 years; 54'% women) were enrolled. TOS and carboxyhemoglobin (COHb) levels in COP patients were increased when compared to control group (p = 0.001). TOS, oxidative stress index (OSI) and COHb levels in COP patients were significantly lower after the treatment. (respectively, p = 0.016; p = 0.023; p = 0.001). On the other hand, no statistical differences were observed in TAS levels of study and control group as well as there were no changes with treatment. CONCLUSION: Measurements of TOS, TAS and OSI levels may be useful markers to find out the pathophsiology of COP.

Comparison of total oxidant/antioxidant status in unconjugated hyperbilirubinemia of newborn before and after conventional and LED phototherapy: A prospective randomized controlled trial.

PURPOSE: We evaluated and compared the oxidant and antioxidant status of hyperbilirubinemic infants before and after the two forms of phototherapy: conventional and LED phototherapy, in order to identify the optimal treatment method. METHOD: Thirty newborns exposed to conventional (Group I) phototherapy and 30 infants exposed to LED phototherapy (Group II) were studied. The serum total antioxidant capacity (TAC) and the total oxidant status (TOS) were assessed by EREL's method. RESULTS: There were no statistically significant differences in TAC or TOS levels between Group I and Group II prior to phototherapy, and no statistically significant difference in TAC levels between the two groups after phototherapy; however, TOS levels were significantly lower in Group II compared to Group I after phototherapy. Oxidative stress index (OSI) increased after conventional phototherapy (p < 0.05) CONCLUSION: The increase in TOS following conventional phototherapy was not not observed following LED phototherapy. This difference should be considered when using phototherapy.

Antioxidant activity, phenolic content, and peroxide value of essential oil and extracts of some medicinal and aromatic plants used as condiments and herbal teas in Turkey.

The antioxidant activity, total peroxide values, and total phenol contents of several medicinal and aromatic plant essential oil and extracts from Turkey were examined. Total phenolic contents were determined using a spectrophotometric technique and calculated as gallic acid equivalents. Total antioxidant activity of essential oil and extracts varied from 0.6853 to 1.3113 and 0.3189 to 0.6119 micromol of Trolox equivalents/g, respectively. The total phenolic content of essential oil ranged from 0.0871 to 0.5919 mg of gallic acid/g dry weight. However, the total phenolic contents of extracts were found to be higher compared with those of essential oils. The amount of total peroxide values of oils varied from 7.31 (pickling herb) to 58.23 (bitter fennel flower) mumol of H(2)O(2)/g. As a result, it is shown that medicinal plant derivatives such as extract and essential oils can be useful as a potential source of total phenol, peroxide, and antioxidant capacity for protection of processed foods.

Fototerapia causa danos ao DNA de leucócitos mononucleares periféricos em recém-nascidos a termo / Phototherapy causes DNA damage in peripheral mononuclear leukocytes in term infants

OBJETIVO: Determinar se a fita de DNA de leucócitos mononucleares endógenos é alvo de fototerapia. MÉTODOS: O estudo incluiu 65 recém-nascidos a termo com idades entre 3 e 10 dias que haviam sido expostos a fototerapia intensiva (n = 23) ou convencional (n = 23) por pelo menos 48 horas devido à icterícia neonatal, além de um grupo controle (n = 19). Dano ao DNA foi avaliado por eletroforese alcalina em gel de célula única (ensaio cometa). A capacidade antioxidante total plasmática e os níveis de estado oxidativo total também foram medidos, e a correlação entre danos ao DNA e estresse oxidativo foi investigada. RESULTADOS: Os valores médios de escores de danos ao DNA nos grupos de fototerapia intensiva e convencional foram significativamente maiores do que os do grupo controle (p < 0,001). Os valores médios e desvio padrão foram 32 (9), 28 (9), 21 (7) unidades arbitrárias, respectivamente. Os níveis de estado oxidativo nos grupos de fototerapia intensiva e convencional foram significativamente maiores do que os do grupo controle (p < 0,005). Os valores médios (desvio padrão) foram 18, 1 (4,2), 16.9 (4,4), 13,5 (4,2) µmol H2O2 equivalente/L, respectivamente. De maneira semelhante, os níveis de estresse oxidativo nos grupos de fototerapia intensiva e convencional foram significativamente maiores do que os do grupo controle (p = 0,041). A capacidade antioxidante total plasmática e os níveis de bilirrubina total não diferiram entre os grupos (p > 0,05). Não houve correlações significativas entre escores de danos ao DNA e bilirrubina, estado oxidante total e níveis de estresse oxidativo entre os grupos de fototerapia (p > 0,05). CONCLUSÕES: Tanto a fototerapia intensiva quanto a convencional causam danos ao DNA dos leucócitos mononucleares endógenos em recém-nascidos a termo com icterícia.

OBJECTIVE: Our aim was to determine whether endogenous mononuclear leukocyte DNA strand is a target of phototherapy. METHODS: The study included 65 term infants aged between 3-10 days that had been exposed to intensive (n = 23) or conventional (n = 23) phototherapy for at least 48 hours due to neonatal jaundice, and a control group (n = 19). DNA damage was assayed by single-cell alkaline gel electrophoresis (comet assay). Plasma total antioxidant capacity and total oxidant status levels were also measured, and correlation between DNA damage and oxidative stress was investigated. RESULTS: Mean values of DNA damage scores in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p < 0.001). Mean values and standard deviation were 32 (9), 28 (9), 21 (7) arbitrary unit, respectively. Total oxidant status levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.005). Mean (standard deviation) values were 18.1 (4.2), 16.9 (4.4), 13.5 (4.2) µmol H2O2 equivalent/L, respectively. Similarly, oxidative stress index levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.041). Plasma total antioxidant capacity and total bilirubin levels did not differ between the groups (p > 0.05). There were no significant correlations between DNA damage scores and bilirubin, total oxidant status and oxidative stress levels in either phototherapy group (p > 0.05). CONCLUSIONS: Both conventional phototherapy and intensive phototherapy cause endogenous mononuclear leukocyte DNA damage in jaundiced term infants.

Phototherapy causes DNA damage in peripheral mononuclear leukocytes in term infants.

OBJECTIVE: Our aim was to determine whether endogenous mononuclear leukocyte DNA strand is a target of phototherapy. METHODS: The study included 65 term infants aged between 3-10 days that had been exposed to intensive (n = 23) or conventional (n = 23) phototherapy for at least 48 hours due to neonatal jaundice, and a control group (n = 19). DNA damage was assayed by single-cell alkaline gel electrophoresis (comet assay). Plasma total antioxidant capacity and total oxidant status levels were also measured, and correlation between DNA damage and oxidative stress was investigated. RESULTS: Mean values of DNA damage scores in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p < 0.001). Mean values and standard deviation were 32 (9), 28 (9), 21 (7) arbitrary unit, respectively. Total oxidant status levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.005). Mean (standard deviation) values were 18.1 (4.2), 16.9 (4.4), 13.5 (4.2) micromol H2O2 equivalent/L, respectively. Similarly, oxidative stress index levels in both the intensive and conventional phototherapy groups were significantly higher than those in the control group (p = 0.041). Plasma total antioxidant capacity and total bilirubin levels did not differ between the groups (p > 0.05). There were no significant correlations between DNA damage scores and bilirubin, total oxidant status and oxidative stress levels in either phototherapy group (p > 0.05). CONCLUSIONS: Both conventional phototherapy and intensive phototherapy cause endogenous mononuclear leukocyte DNA damage in jaundiced term infants.

Total oxidative/anti-oxidative status and relation to bone mineral density in osteoporosis.

The aim of this study was to evaluate the total antioxidant status (TAS), total oxidative status (TOS) and oxidative stress index (OSI) in patients with postmenopausal osteoporosis. We also investigate the relation between bone mineral density and oxidative/antioxidative parameters. Thirty-nine patients with osteoporosis and 26 healthy controls were included in the study. Plasma TAS, TOS levels were determined by using a novel automated methods. Plasma TOS and OSI value were significantly higher, and plasma TAS level was lower in patients than in healthy controls (P < 0.001 for all). There was a significant negative correlation between OSI and BMD in lumbar and femoral neck region (r = -0.63, P < 0.001; r = 0.40, P = 0.018). The results of this study indicated that increased osteoclastic activity and decreased osteoblastic activity may be associated with an imbalance between oxidant and antioxidant status in postmenopausal osteoporosis. Therefore, supplementation of antioxidant-enriched diet to the therapy might shed light on the development of novel therapeutic strategies for osteoporosis.

Estado oxidante/antioxidante total em recém-nascidos ictéricos antes e depois da fototerapia / Total oxidant/antioxidant status in jaundiced newborns before and after phototherapy

OBJETIVO: Avaliar o efeito da fototerapia no estado oxidante e antioxidante no soro de recém-nascidos a termo com hiperbilirrubinemia. MÉTODO: Trinta e quatro recém-nascidos a termo com idades entre 3 e 10 dias submetidos a fototerapia foram avaliados. O estado antioxidante do soro foi determinado pela capacidade antioxidante total e por componentes antioxidantes individuais: vitamina C, ácido úrico, albumina, concentração de tiol e bilirrubina total. O estado oxidante foi avaliado através do estado oxidante total, índice de estresse oxidativo e componentes oxidantes individuais: malondialdeído e níveis de hidroperóxido lipídico. RESULTADOS: As concentrações de vitamina C, ácido úrico, bilirrubina total e malondialdeído foram significativamente mais baixas, enquanto que o estado oxidante total, níveis de hidroperóxido lipídico e o índice de estresse oxidativo foram significativamente maiores após a fototerapia (p < 0,05). Houve correlações positivas significativas entre a bilirrubina sérica total e a concentração de malondialdeído (r = 0,434, p = 0,001). CONCLUSÕES: Embora a concentração de malondialdeído tenha diminuído após a fototerapia, esta exerce um efeito negativo sobre as diversas partes do sistema de defesa oxidante/antioxidante em recém-nascidos a termo ictéricos, expondo-os a um possível estresse oxidativo.

OBJECTIVE: To assess the effect of phototherapy on serum oxidant and antioxidant status in hyperbilirubinemic full-term newborns. METHOD: Thirty-four full-term infants from 3 to 10 days of age exposed to phototherapy were studied. The serum antioxidant status was assessed by measuring the total antioxidant capacity (TAC) and individual antioxidant components: vitamin C, uric acid, albumin, thiol contents and total bilirubin. The oxidant status was assessed by determining the total oxidant status (TOS), oxidative stress index (OSI) and individual oxidant components: malondialdehyde (MDA), and lipid hydroperoxide levels. RESULTS: Vitamin C, uric acid, total bilirubin and MDA concentration were significantly lower, whereas serum TOS, lipid hydroperoxide and OSI levels were significantly higher after phototherapy (p < 0.05). There were significant positive correlations between serum total bilirubin and MDA (r = 0.434, p = 0.001). CONCLUSIONS: Although the MDA level was reduced after phototherapy, phototherapy has a negative impact on numerous parts of the oxidant/antioxidant defense system in jaundiced full-term newborns, exposing them to potential oxidative stress.

Total oxidant/antioxidant status in jaundiced newborns before and after phototherapy.

OBJECTIVE: To assess the effect of phototherapy on serum oxidant and antioxidant status in hyperbilirubinemic full-term newborns. METHOD: Thirty-four full-term infants from 3 to 10 days of age exposed to phototherapy were studied. The serum antioxidant status was assessed by measuring the total antioxidant capacity (TAC) and individual antioxidant components: vitamin C, uric acid, albumin, thiol contents and total bilirubin. The oxidant status was assessed by determining the total oxidant status (TOS), oxidative stress index (OSI) and individual oxidant components: malondialdehyde (MDA), and lipid hydroperoxide levels. RESULTS: Vitamin C, uric acid, total bilirubin and MDA concentration were significantly lower, whereas serum TOS, lipid hydroperoxide and OSI levels were significantly higher after phototherapy (p < 0.05). There were significant positive correlations between serum total bilirubin and MDA (r = 0.434, p = 0.001). CONCLUSIONS: Although the MDA level was reduced after phototherapy, phototherapy has a negative impact on numerous parts of the oxidant/antioxidant defense system in jaundiced full-term newborns, exposing them to potential oxidative stress.