The relationship between fetal and maternal selenium concentrations in sheep and goats

In this study, biological samples (slaughterhouse material) were collected from 30 sheep and 36 goats and classified according to gestational stage into either early or late gestation. Samples consisted of allantoic fluid, amniotic fluid, fetal liver, fetal kidney, fetal thyroid gland, maternal plasma and liver to determine selenium (Se) concentrations throughout gestation. The Se concentrations in the allantoic fluid, fetal liver and kidney increased significantly (p < 0.01) during late gestation. Concurrently, the Se concentrations in amniotic fluid, maternal plasma and liver decreased significantly (p < 0.01) over time. Significant (p < 0.01) positive relationships were recorded between the age of the fetus and Se concentrations in the allantoic fluid (r = 0.57–0.75), fetal liver (r = 0.43–0.59) and kidney (r = 0.80–0.81) in both sheep and goats. A significant (p < 0.05) positive relationships were also recorded between the Se concentrations in the allantoic fluid and fetal liver (r = 0.35–0.37), the maternal plasma and liver Se concentrations (r = 0.37–0.57) between sheep and goats. A significant (p < 0.05) negative correlation was recorded between the Se concentrations in the allantoic fluid with maternal plasma of sheep (r = −0.41) as well as between the fetal liver and maternal liver Se (r = −0.22 to 0.50) and a negative correlation (r = −0.42 to 0.43) (p < 0.01) between Se concentrations in the fetal liver and amniotic fluid in both sheep and goats, respectively. Se concentration in the fetal liver was significantly (p < 0.01) higher than that of the kidney and thyroid. In the thyroid gland no morphological differences were noted. Strong fetal–maternal relationships in Se concentration were evident throughout the gestational period and dams seem to sacrifice Se levels in order to maintain that in the fetus. Se concentrations in the amniotic and allantoic fluids could be used as a possible indicator of the Se status of the fetus throughout gestation.     

Plasma levels of transforming growth factor-beta 1 before and after removal of low- and high-grade astrocytomas

Transforming growth factor-beta 1 (TGF-β1) has been reported to be a possible marker for a number of tumors, including brain tumors. The aim of this study was to measure the plasma levels of TGF-β1 in patients with low- and high-grade astrocytomas before and after surgery. This prospective study included 14 patients with low-grade astrocytomas and 25 with high-grade astrocytomas who underwent tumor removal and 13 controls (patients who underwent cranioplasty for skull bone defects). Plasma levels of TGF-β1 were measured in all subjects using enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristic (ROC) curve analysis showed that when the level of TGF-β1 before tumor removal was ?2.52 ng/ml, astrocytoma was predicted with a sensitivity of 94.9% and specificity of 100%. The mean plasma level of TGF-β1 in both the low-grade and high-grade astrocytoma groups significantly decreased after tumor removal (p < 0.05); there was no significant change in TGF-β1 plasma level of the controls following surgery. Patients with high-grade astrocytomas had a significantly higher mortality rate than patients with low-grade astrocytomas (p = 0.019) and significantly shorter survival (p = 0.008). A positive correlation between TGF-β1 level after tumor removal and tumor volume was only found in the high-grade astrocytoma group (γ = 0.597, p = 0.002). The findings show that plasma TGF-β1 level was increased in patients with low-grade and high-grade astrocytoma, and that the levels significantly decreased after tumor removal in both groups. The results provide additional evidence that TGF-β1 might be useful as a tumor marker for astrocytomas.     

Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes

The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes.Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻]_b), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U_SG) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT_OXR), carbohydrate oxidation (CHO_OXR), energy expenditure from fat (EE_FAT), from carbohydrates (EE_CHO) and total EE (EE_T) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P < 0.05.No significant differences were found in U_SG between, before, and after the test (1.014 ± 0.004 vs. 1.014 ± 0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r = 0.332, P < 0.001) and Se (r = 0.242, P < 0.01) with [La⁻]_b, but no relationships were established between [La⁻]_b, VO₂, FAT_OXR, CHO_OXR, EE_FAT, EE_CHO, or EE_T and plasma ion levels.Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.     

Copper/zinc and copper/selenium ratios,and oxidative stress as biochemical markers in recurrent aphthous stomatitis

ProjectRecurrent aphthous stomatitis (RAS) is a common oral mucosal disorder characterized by recurrent, painful oral aphthae, and oxidative stress presumably contributes to its pathogenesis. The aim of this study is to scrutinize the relationship between oxidative stress and serum trace elements (copper, Cu; zinc, Zn; selenium, Se), and to evaluate the ratios of Cu/Zn and Cu/Se in this disorder.ProcedurePatients with RAS (n = 33) and age- and sex-matched healthy control subjects (n = 30) were enrolled in this study. Malondialdehyde (MDA) concentrations in plasma and the activities of superoxide dismutase (SOD1; CuZnSOD), glutathione peroxidase (GPx) and catalase (CAT) in erythrocyte were determined as spectrophotometric. Also, the levels of Se, Zn and Cu in serum were determined on flame and furnace atomic absorption spectrophotometer using Zeeman background correction.Results and conclusionsOxidative stress was confirmed by the significant elevation in plasma MDA, and by the significant decrease in CAT, SOD1, and GPx (p < 0.05). When compared to controls, Zn and Se levels were significantly lower in patients, whereas Cu levels was higher in RAS patients than those in controls (p < 0.05). In addition, the correlation results of this study were firstly shown that there were significant and positive correlations between Se–CAT, Se–GPx, and Cu–MDA parameters, but negative correlations between Se–Cu, Se–MDA, Cu–CAT, Cu–SOD1 and Cu–GPx parameters in RAS patients. Furthermore, the ratios of Cu/Zn and Cu/Se were significantly higher in the patients than the control subjects (p < 0.05). Our results indicated that lipid peroxidation associated with the imbalance of the trace elements seems to play a crucial role in the pathogenesis of RAS. Furthermore, the serum Cu/Zn and Cu/Se ratios may be used as biochemical markers in these patients.     

Selenium status in elderly: Relation to cognitive decline

Studies show that decreased antioxidant system is related to cognitive decline. Thus we aimed to measure selenium (Se) status in Alzheimer's disease (AD) and mild cognitive impairment (MCI) elderly and compared them with a control group (CG). 27 AD, 17 MCI and 28 control elderly were evaluated. Se concentration was determined in plasma and erythrocyte by using hydride generation atomic absorption spectroscopy. Erythrocyte Se concentration in AD group was lower than CG (43.73 ± 23.02 μg/L and 79.15 ± 46.37 μg/L; p = 0.001), but not statistically different from MCI group (63.97 ± 18.26 μg/L; p = 0.156). AD group exhibited the lowest plasma Se level (34.49 ± 19.94 μg/L) when compared to MCI (61.36 ± 16.08 μg/L; p = 0.000) and to CG (50.99 ± 21.06 μg/L; p = 0.010). It is observed that erythrocyte Se decreases as cognition function does. Since erythrocyte reflects longer-term nutritional status, the data point to the importance of the relation between Se exposure and cognitive function. Our findings suggest that the deficiency of Se may contribute to cognitive decline among aging people.     

Evening salivary cortisol and alpha-amylase at 14 months and neurodevelopment at 4 years: Sex differences

Stress system activity in early life can have long-term effects on neurodevelopment. The main aim of this study was to assess the association of child evening salivary cortisol and alpha-amylase basal levels at 14 months of age with longer-term neuropsychological development at 4 years in a low-risk population-based birth cohort derived from the INMA (Environment and Childhood) project in Spain. We included 186 parent-children pairs with information on both stress system activity and neurodevelopment. Both stress markers at 14 months of age showed an association with neuropsychological development at 4 years. Salivary cortisol showed a sex-specific pattern of association. In girls, cortisol levels at 14 months were negatively associated with cognitive development [long-term declarative memory (β = − 17.8, p = 0.028; 95% CI = − 33.2 to − 2.5); executive function (β = − 9.8, p = 0.08; 95% CI = − 21 to 1)] and gross motor development (β = − 13; p = 0.022; 95% CI = − 24 to − 2), whereas in boys cortisol levels were negatively associated with socioemotional development [autistic-like behaviours: Incidence Rate Ratio (IRR) = 1.6, p = 0.039; 95% CI = 1.01 to 2.41]. Salivary alpha-amylase was positively associated with socioemotional development in boys only [social competence (β = 2.11, p = 0.013; 95% CI = 0.47 to 3.72), autistic-like behaviours (IRR = 0.93, p = 0.042; 95% CI = 0.87 to 0.99) and hyperactivity symptoms (IRR = 0.81, p = 0.021; 95% CI = 0.69 to 0.97)]. These results suggest that stress system activity in early life is associated with longer-term neurodevelopment and that sex is an important factor in this relationship.     

Interactions between Glutathione-S-Transferase M1, T1 and P1 polymorphisms and smoking,and increased susceptibility to esophageal squamous cell carcinoma

Background: A complex of genetic and environmental factors is involved in carcinogenesis of the esophageal squamous cell carcinoma (ESCC). Glutathione-S-Transferases (GSTs) are phase-II enzymes playing role in detoxification of carcinogen electrophiles. Genetic polymorphisms of GSTM1, GSTT1 and GSTP1 in association with some environmental factors and their impact on esophageal cancer susceptibility were assessed in the Iranian population. Methods: Genomic DNA of peripheral blood leukocytes from 148 confirmed esophageal cancer cases and 137 healthy individuals as control group was assayed for restriction fragment length polymorphisms in the GSTP1 loci by PCR amplification followed by digestion with Alw26I. Deletion of the GSTM1 and GSTT1 genes was detected by multiplex PCR. A data-mining method based on decision trees was applied to produce a predictive model of interactions between genotypes. Results: Smoking was independently associated with ESCC (p < 0.05, OR: 2.286, 95% CI = 1.311–3.983). Smoking along with GSTP1 Val/Val genotype was associated to ESCC (p < 0.001, OR: 3.886, 95% CI = 1.830–8.251), while non-smokers with GSTP1 Val/Val were significantly more frequent in non-cancerous group. (p = 0.007, OR: 0.507, 95% CI = 0.309–0.830). Conclusions: Data-mining methods are useful tools to map out a scheme for predicting complex relations and combinations of different genotypes. Genotyping analysis of GSTP1 together with assessment of smoking seems to be important in determining the risk of ESCC in the Iranian population.     

Plasma levels of trace elements and exercise induced stress hormones in well-trained athletes

This study analyzed the variation and relationship of several trace elements, metabolic substrates and stress hormones activated by exercise during incremental exercise. Seventeen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, the workload was increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Prior diet, activity patterns, and levels of exercise training were controlled, and tests timed to minimize variations due to the circadian rhythm. Oxygen uptake, blood lactate concentration, plasma ions (Zn, Se, Mn and Co), serum glucose, non-esterified fatty acids (NEFAs) and several hormones were measured at rest, at the end of each stage and 3, 5 and 7 min post-exercise. Urine specific gravity was measured before and after the test, and participants drank water ad libitum.Significant differences were found in plasma Zn and Se levels as a function of exercise intensity. Zn was significantly correlated with epinephrine, norepinephrine and cortisol (r = 0.884, P < 0.01; r = 0.871, P < 0.01; and r = 0.808, P = 0.05); and Se showed significant positive correlations whit epinephrine and cortisol (r = 0.743, P < 0.05; and r = 0.776, P < 0.05). Neither Zn nor Se levels were associated with insulin or glucagon, and neither Mn nor Co levels were associated with any of the hormones or substrate metabolites studied. Further, while Zn levels were found to be associated only with lactate, plasma Se was significantly correlated with lactate and glucose (respectively for Zn: r = 0.891, P < 0.01; and for Se: r = 0.743, P < 0.05; r = 0.831, P < 0.05).In conclusion, our data suggest that there is a positive correlation between the increases in plasma Zn or Se and stress hormones variations induced by exercise along different submaximal intensities in well-hydrated well-trained endurance athletes.     

Effect of supplementation with Se-enriched yeast and factors influencing Se concentration in plasma of transplant recipients

The aim of this study was to assess the bioavailability of selenium (Se) in Se-enriched yeast and the possible impact of age, sex and area of residence on the Se concentration in plasma in 179 transplant recipients, as Se clinical effects in the prevention of cutaneous epithelial lesions in organ transplant recipients has been reported elsewhere. Subjects were randomized to receive either 200 μg Se/day (group 1:91 patients) or placebo (group 2: 88 patients) for 3 years. Plasma Se levels were measured at the beginning of the study and after 4, 12, 24 and 36 months of Se or placebo supplementation. Initial plasma Se levels were 90.9±26.1 μg/L for placebo and 94.0±25.3 μg/L for Se-supplemented groups. At baseline, the Se level was not linked to sex and age but to area of residence, although the number of subjects in each area was insufficient to draw any conclusions. Plasma Se levels were statistically lower in cases of liver transplant compared to kidney and heart transplant (p=0.03). Over the 3-year period of supplementation, plasma Se in the supplemented subjects was significantly higher than in the placebo group (p<0.01) and there was an interaction (p<0.01) between supplementation and time for plasma Se. Supplementation with Se-enriched yeast significantly increased the Se concentration in plasma of the patients to a plateau: the mean plasma Se of the Se-supplemented patients increased to 164.7±35.8 μg/L at 4 months and then remained similar at 12 (176.1±48.3 μg/L), 24 (176.1±54.2 μg/L) and 36 (182.2±46.4 μg/L) months.     

Plasma zinc in adults with cystic fibrosis: Correlations with clinical outcomes

BackgroundZinc status has been previously documented in cystic fibrosis (CF) infants, children and adolescents. However, despite the increasing life expectancy observed in CF populations, data regarding zinc status of CF adults are surprisingly lacking. The objectives of this study were to (1) characterize zinc status and (2) explore associations between zinc status and clinical outcomes of CF adult patients.MethodsA retrospective chart review was performed for patients who had their plasma zinc measured between 2009 and 2012. Data included demographics, clinical characteristics, biochemical parameters and co-morbid conditions.ResultsA total of 304 CF patients were included in the study. These patients displayed a good nutritional status (mean BMI ± SD: 22.7 ± 3.5) and moderate lung disease (mean FEV₁ ± SD: 66.3 ± 22.2). Low plasma zinc concentration (<9.2 μmol/L) was found in 68 out of 304 CF patients (22.4%). Compared to patients with normal zinc, those with low zinc had significantly lower forced vital capacity and forced expiratory volume in one second. 72% of CF adults with low zinc suffered from bone disease (vs 49% with normal zinc, p = 0.037) and 79% had impaired glycemic status (vs 58%, p = 0.016). Accordingly, negative correlations were found between plasma zinc and glucose (r = −0.139, p = 0.0001), HbA1c (r = −0.237, p = 0.0001) and fructosamine (r = −0.134, p = 0.034). In multiple linear regression, albumin and glycemic status were significant predictors of plasma zinc.ConclusionOur data indicated that nearly one quarter of CF adults with good nutritional status and moderate lung disease had low plasma zinc concentration and that low zinc status was associated with worse clinical outcomes.     

The interface of hypothalamic–pituitary–adrenocortical axis and circulating brain natriuretic peptide in prediction of cardiopulmonary performance during physical stress

Brain natriuretic peptide (NT-pro-BNP) was implicated in the regulation of hypothalamic–pituitary–adrenocortical (HPA) responses to psychological stressors. However, HPA axis activation in different physical stress models and its interface with NT-pro-BNP in the prediction of cardiopulmonary performance is unclear. Cardiopulmonary test on a treadmill was used to assess cardiopulmonary parameters in 16 elite male wrestlers (W), 21 water polo player (WP) and 20 sedentary age-matched subjects (C). Plasma levels of NT-pro-BNP, cortisol and adrenocorticotropic hormone (ACTH) were measured using immunoassay sandwich technique, radioimmunoassay and radioimmunometric techniques, respectively, 10 min before test (1), at beginning (2), at maximal effort (3), at 3rd min of recovery (4). In all groups, NT-pro-BNP decreased between 1 and 2; increased from 2 to 3; and remained unchanged until 4. ACTH increased from 1 to 4, whereas cortisol increased from 1 to 3 and stayed elevated at 4. In all groups together, ΔNT-pro-BNP2/1 predicted peak oxygen consumption (B = 37.40, r = 0.38, p = 0.007); cortisol at 3 predicted heart rate increase between 2 and 3 (r = −0.38,B = −0.06, p = 0.005); cortisol at 2 predicted peak carbon-dioxide output (B = 2.27, r = 0.35, p < 0.001); ΔACTH3/2 predicted peak ventilatory equivalent for carbon-dioxide (B = 0.03, r = 0.33, p = 0.003). The relation of cortisol at 1 with NT-pro-BNP at 1 and 3 was demonstrated using logistic function in all the participants together (for 1/cortisol at 1 B = 63.40, 58.52; r = 0.41, 0.34; p = 0.003, 0.013, respectively). ΔNT-pro-BNP2/1 linearly correlated with ΔACTH4/3 in WP and W (r = −0.45, −0.48; p = 0.04, 0.04, respectively). These results demonstrate for the first time that HPA axis and NT-pro-BNP interface in physical stress probably contribute to integrative regulation of cardiopulmonary performance.     

Serum and urinary selenium levels in obese children: A cross-sectional study

ObjectiveTo determine serum and urinary selenium (Se) levels in children with and without obesity, and to assess if Se influences the risk of obesity.Subjects and methodsHigh-resolution-continuum source-atomic absorption spectrometry (HR-CS-AAS) was used to determine the content of Se in 80 children (age 6–17; 40 boys, 40 girls). Correlations between variables were tested with the use of Spearman's correlation coefficient. U Mann–Whitney test was applied to assess the difference of Se contents in samples. Measured metabolic risk factors (blood pressure, glucose level, triglycerides (TG), low-density lipoprotein (LDL), high-density lipoprotein (HDL), and total cholesterol), age, gender, and BMI were correlated. Logistic regression models were fitted to identify predictors of obesity interacting with selenium content in serum and urine, separately.ResultsObese children, regardless of gender, had lower Se content. Se level in serum (p = 0.001, OR 0.74, 95%CI 0.62–0.88) and total cholesterol (p = 0.001, OR 1.19, 95%CI 1.08–1.31) were the independent factors significantly influencing the risk of obesity in children. Two separate models were observed for Se in urine: (i) Se level (p < 0. 0001, OR 0.70, 95%CI 0.58–0.84) and glucose level (p < 0.0001, OR 1.22, 95%CI 1.10–1.35), and (ii) Se level (p = 0.002, OR 0.60 95%CI 0.43–0.83) and total cholesterol level (p = 0.003, OR 1.16, 95%CI 1.05–1.28).ConclusionThe current study suggests a possible role of Se in obesity. Further research needs to be performed to check if obese children are an at-risk group for Se deficiency.     

Fire service instructor's undergarment choice to reduce Interleukin-6 and minimise physiological and perceptual strain

Fire Service Instructors frequently experience high levels of physiological and perceptual strain during live fire exposures. Instructors are also at risk of cardiovascular illnesses, with cardiac death being the greatest cause of fire fighter death. Current practice for UK instructors is to select undergarment type based on personal preference, between a boiler suit (BOILER) and a wicking base layer (WBL). Research suggests that shorts and t-shirt (SHORTS) may also be a beneficial alternative undergarment choice. The UK South East Fire Service requested an investigation to identify if undergarment selection can lessen the strain experienced by instructors, and reduce the acute inflammatory response to fire exposures. Eight males completed three 45 min sessions in a heat chamber (49.5±1.4 °C and 16.9±4.3% RH) whilst performing intermittent walking. At the end of heat exposure change in heart rate was not effected by garment type (p=0.061, ηp²=0.373). Change in rectal temperature was different between garments (p=0.009, η_p²=0.271), with trends suggesting that BOILER resulted in a greater change (1.03±0.60 °C) than SHORTS (0.76±0.37 °C, p=0.589, d=0.21) and WBL (0.72±0.33 °C, p=0.545, d=0.25). Interleukin-6 post exposure was greater for BOILER (6.96±0.28 pg mL⁻¹) than both SHORTS (6.59±0.30 pg mL⁻¹, p=0.043, d=0.42) and WBL (6.45±0.43 pg mL⁻¹, p=0.031, d=0.51). Overall, undergarment type had little impact on physiological or perceptual strain. However, wearing WBL or SHORTS may reduce the inflammatory response, and consequently decrease the risk of cardiovascular events.     

Determination of potential role of antioxidative status and circulating biochemical markers in the pathogenesis of ethambutol induced toxic optic neuropathy among diabetic and non-diabetic patients

The present study was designed to explore the antioxidative status and circulating biochemical markers having a potential role in the pathogenesis of ethambutol (EMB) induced toxic optic neuropathy (TON) among diabetic and non-diabetic patients.Fifty patients under complete therapy of EMB for tuberculosis were included in the present study. Inclusion criteria for patients were to receive EMB everyday during treatment, a dose of 25 mg/kg for initial 2 months and 15 mg/kg during the rest of therapy period. We conducted color vision and visual acuity test for all patients.Fifteen out of fifty EMB induced TON patients, were found to be diabetic. Color vision and visual acuity test results were evaluated for diabetic and non-diabetic as well as twenty age matched controls. The results demonstrated a significant pattern of circulating biochemical markers between the studied groups. Data regarding hematological (RBC, p value = 0.02; Hemoglobin, p value = 0.02), hepatic (total bilirubin, p value = 0.01), renal (urea, p value = 0.03; creatinine, p value = 0.007), lipid (total cholesterol, p value = 0.01; total triglycerides, p value = 0.03) and antioxidative (superoxide dismutase, p value = 0.005; glutathione, p value = 0.02; catalase, p value = 0.02) profile showed a highly significant difference among the studied groups specially patients with diabetes. Malondialdehyde (MDA) level had gone significantly up in diabetic TON patients (p value = 0.02), in comparison to other antioxidants and vitamins (Vit). Vit-A, E, B₁, B₁₂ and Zinc seem to be playing a major role in the pathogenesis of TON, specially Vit-E and B₁ surpassed all the antioxidants as having highly significant inverse relationships with MDA (MDA vs Vit-E, r = −0.676^** and MDA vs Vit-B₁, r = −0.724^** respectively).We conclude that during the ethambutol therapy the decreased levels of Vit-E and Vit-B₁ possibly play a role in the development of TON and may be used as therapeutic agents to lessen the deleterious effects of ethambutol.     

Selenium uptake,speciation and stressed response of Nicotiana tabacum L.

The research on the function and mechanism of selenium (Se) is of great significance for the development of Se-enriched agricultural products. In this paper, uptake, speciation distribution, the effects on the flue-cured tobacco growth and antioxidant system of Se at different levels (0–22.2 mg Se kg⁻¹) were studied through a pot experiment, aiming to clarify flue-cured tobacco's response to Se stress and the relationship between Se speciation and antioxidant system. The results showed that the leaf area and number, the biomass and the chlorophyll content reached the maximum at 4.4 mg kg⁻¹ of Se treatment. Selenium at low levels (≤4.4 mg kg⁻¹) stimulated the growth of flue-cured tobacco by elevating the capability of antioxidant stress and reducing the malondialdehyde (MDA) content to 0.6–0.8 times of that of the control. However, high Se levels (≥11.1 mg kg⁻¹) depressed the capability of antioxidant stress and raised the MDA content to 1.5-fold of that of the control, and meanwhile the biomass of the aboveground parts and underground parts declined notably. The Se content in different parts of flue-cured tobacco significantly increased with the growth of Se levels. The range of Se content in roots, leaves and stems at 2.2–22.2 mg kg⁻¹ of Se treatment were 16.7–58.6 mg kg⁻¹, 2.6–37.3 mg kg⁻¹ and 2.2–10.3 mg kg⁻¹, respectively. According to the detection of different Se speciation, only selenocysteine (SeCys) was detectable in leaves at 2.2 mg kg⁻¹ Se treatment; SeCys, selenite [Se(IV)]and selenate [Se(VI)] were detected in flue-cured tobacco leaves at Se treatment (≥4.4 mg kg⁻¹), which accounted for 4.6–10%, 9–18.7% and 71–86% respectively; SeCys, selenomethionine (SeMet) and Se(IV) were detected in roots, and organic selenium(66–84%) was the main Se species at Se ≤ 11.1 mg kg⁻¹ treatment; four Se species [SeCys, SeMet, Se(IV) and Se(VI)] were detected in flue-cured tobacco roots, and the main Se species was inorganic Se (60%) at 22.2 mg kg⁻¹ Se treatment. That was to say, the percentage of organic Se species (SeCys and SeMet in flue-cured tobacco leaves and root) declined, whereas the ratio of inorganic Se species [Se(IV) and Se(VI)] increased with the growth of Se levels. The correlation analysis showed that the superoxide dismutase (SOD) activity as well as the glutathione (GSH) and MDA contents were positively correlated with the Se(IV) and Se(VI) contents at P < 0.01 and excessive inorganic Se might destruct the reactive oxygen species (ROS) balance and enhance the MDA content, thus causing damage to the plant growth. In a word, the present study suggested that the ratio of inorganic Se [Se(IV) and Se(VI)] was closely related with the growth and the antioxidant capacity of flue-cured tobacco and the excessive application of Se led to the higher proportion of inorganic Se and poorer antioxidant capacity, which ultimately inhibited the growth of flue-cured tobacco.     

Neuromuscular adaptations predict functional disability independently of clinical pain and psychological factors in patients with chronic non-specific low back pain

Patients with chronic low back pain exhibit characteristics such as clinical pain, psychological symptoms and neuromuscular adaptations. The purpose of this study was to determine the independent contribution of clinical pain, psychological factors and neuromuscular adaptations to disability in patients with chronic low back pain. Clinical pain intensity, pain catastrophizing, fear-avoidance beliefs, anxiety, neuromuscular adaptations to chronic pain and neuromuscular responses to experimental pain were assessed in 52 patients with chronic low back pain. Lumbar muscle electromyographic activity was assessed during a flexion–extension task (flexion relaxation phenomenon) to assess both chronic neuromuscular adaptations and neuromuscular responses to experimental pain during the task. Multiple regressions showed that independent predictors of disability included neuromuscular adaptations to chronic pain (β = 0.25, p = 0.006, sr² = 0.06), neuromuscular responses to experimental pain (β = −0.24, p = 0.011, sr² = 0.05), clinical pain intensity (β = 0.28, p = 0.002, sr² = 0.08) and psychological factors (β = 0.58, p < 0.001, sr² = 0.32). Together, these predictors accounted for 65% of variance in disability (R² = 0.65 p < 0.001). The current investigation revealed that neuromuscular adaptations are independent from clinical pain intensity and psychological factors, and contribute to inter-individual differences in patients’ disability. This suggests that disability, in chronic low back pain patients, is determined by a combination of factors, including clinical pain, psychological factors and neuromuscular adaptations.     

Transforming growth factor beta 1 (TGF-β1) modulates Epstein-Barr virus reactivation in absence of Helicobacter pylori infection in patients with gastric cancer

BackgroundTransforming growth factor-beta 1 (TGF-β1), a multifunctional cytokine, acts as a key factor for Epstein-Barr virus (EBV) reactivation. We investigated the role of TGF-β1 in latent and lytic stages of EBV in relation to Helicobacter pylori infection among patients with gastric cancer (GC) and peptic ulcer disease (PUD).MethodGastric mucosal TGF-β1 expression was determined in 95 EBV positive patients with gastroduodenal pathology [GC 40, PUD 19 and non-ulcer dyspepsia (NUD) 36] by quantitative real time PCR. Presence of H. pylori infection was diagnosed when either culture or any two of three tests (RUT, histopathology and specific ureA PCR) were positive. Serum level of TGF-β1 was detected among 60 patients using ELISA.ResultsMucosal TGF-β1 mRNA expression was detected in 85 of 95 EBV positive patients and it was significantly higher in patients with GC (p = 0.042). TGF-β1 expression tended to be higher among H. pylori non-infected than infected patients (3.80 ± 6.24 vs. 2.07 ± 2.50, p = 0.085). Both mRNA and serum level had significant association with lytic stage of EBV in absence of H. pylori infection when compared with its presence (5.21 ± 4.00 vs. 2.29 ± 2.89, p = 0.040 and 842.00 [669.55] vs. 662.63 [628.76], p = 0.049; respectively).ConclusionTGF-β1 expression was significantly associated with GC. TGF-β1 was higher both at expression and translational levels in lytic EBV infection without H. pylori suggests that H. pylori infection might play important role in preventing EBV reactivation through attenuated TGF-β1 expression. This might be a “wise host defense against EBV reactivation”.     

Plasma levels of intermedin (adrenomedullin-2) in healthy human volunteers and patients with heart failure

Intermedin/adrenomedullin-2 (IMD) is a member of the adrenomedullin/CGRP peptide family. Less is known about the distribution of IMD than for other family members within the mammalian cardiovascular system, particularly in humans. The aim was to evaluate plasma IMD levels in healthy subjects and patients with chronic heart failure. IMD and its precursor fragments, preproIMD_25–56 and preproIMD_57–92, were measured by radioimmunoassay in 75 healthy subjects and levels of IMD were also compared to those of adrenomedullin (AM) and mid-region proadrenomedullin_45–92 (MRproAM_45–92) in 19 patients with systolic heart failure (LVEF < 45%). In healthy subjects, plasma levels (mean + SE) of IMD (6.3 + 0.6 pg ml⁻¹) were lower than, but correlated with those of AM (25.8 + 1.8 pg ml⁻¹; r = 0.49, p < 0.001). Plasma preproIMD_25–56 (39.6 + 3.1 pg ml⁻¹), preproIMD_57–92 (25.9 + 3.8 pg ml⁻¹) and MRproAM_45–92 (200.2 + 6.7 pg ml⁻¹) were greater than their respective bioactive peptides. IMD levels correlated positively with BMI but not age, and were elevated in heart failure (9.8 + 1.3 pg ml⁻¹, p < 0.05), similarly to MRproAM_45–92 (329.5 + 41.9 pg ml⁻¹, p < 0.001) and AM (56.8 + 10.9 pg ml⁻¹, p < 0.01). IMD levels were greater in heart failure patients with concomitant renal impairment (11.3 + 1.8 pg ml⁻¹) than those without (6.5 + 1.0 pg ml⁻¹; p < 0.05). IMD and AM were greater in patients receiving submaximal compared with maximal heart failure drug therapy and were decreased after 6 months of cardiac resynchronization therapy. In conclusion, IMD is present in the plasma of healthy subjects less abundantly than AM, but is similarly correlated weakly with BMI. IMD levels are elevated in heart failure, especially with concomitant renal impairment, and tend to be reduced by high intensity drug or pacing therapy.     

Investigation on the properties and kinetics of glucose-fed aerobic granular sludge

Aerobic granulation is a process in which suspended biomass aggregate and form discrete well-defined granules in aerobic systems. To investigate the properties and kinetics of aerobic granular sludge, aerobic granules were cultivated with glucose synthetic wastewater in a series of sequencing batch reactors (SBR). The spherical shaped granules were observed on 8th day with the mean diameter of 0.1 mm. With the organic loading rate (OLR) being increased to 4.0 g COD L⁻¹ d⁻¹, aerobic granules grew matured with spherical shape. The size of granules ranged from 1.2 to 1.8 mm, and the corresponding settling velocity of individual granule was 24.2–36.4 m h⁻¹. The oxygen utilization rate (OUR) of mature granules was 41.90 g O₂ kg MLSS⁻¹ h⁻¹, which was two times higher than that of activated sludge (18.32 g O₂ kg MLSS⁻¹ h⁻¹). The experimental data indicated that the substrate utilization and biomass growth kinetics generally followed Monod's kinetics model. The corresponding kinetic coefficients of k (maximum specific substrate utilization rate), K_s (half velocity coefficient), Y (growth yield coefficient) and K_d (decay coefficient) were determined as follows, k_c = 23.65 d⁻¹, K_c = 3367.05 mg L⁻¹, K_N = 0.038 d⁻¹, K_N = 29.65 mg L⁻¹, Y = 0.1927–0.2022 mg MMLS (mg COD)⁻¹ and K_d = 0.00845–0.0135 d⁻¹, respectively. Those properties of aerobic granules made aerobic granules system had a short setup period, high substrate utilization rate and low sludge production.