The receptor for advanced glycation endproducts and its ligands in patients with myasthenia gravis

ObjectiveMyasthenia gravis (MG) is a T- and B-cell mediated autoimmune disorder affecting the neuromuscular junction. The receptor for advanced glycation endproducts (RAGE) plays a role in the amplification of chronic inflammatory disorders and autoimmune diseases. We sought to investigate the role of RAGE and its ligands in the pathophysiology of MG.MethodsIn this cross-sectional study we enrolled 42 patients with MG and 36 volunteers. We employed enzyme-linked immunosorbent assays to determine the concentration of soluble RAGE (sRAGE) and high mobility group box 1 (HMGB1) in serum of patients and volunteers. In a subpopulation of patients we measured the serum levels of endogenous secretory (es) RAGE and various RAGE ligands, such as S100B, S100A8 and advanced glycation endproducts (AGE-CML). Reported are means and standard error mean.ResultsWe found significantly reduced levels of the soluble receptors sRAGE and esRAGE in patients with MG compared to volunteers without MG (sRAGE [pg/ml] 927.2 ± 80.8 vs. 1400.1 ± 92.4; p < 0.001; esRAGE [pg/ml] 273.5 ± 24.6 vs. 449.0 ± 22.4; p < 0.001). Further categorization of patients with MG according to the distribution of muscle involvement revealed the following sRAGE concentrations: generalized MG 999.4 ± 90.8 and ocular MG 696.1 ± 161.8 (vs. control; One-way ANOVA: p < 0.001; Post hoc analysis: generalized vs. ocular MG: p = 0.264, generalized MG vs. control: p = 0.008, ocular MG vs. control: p = 0.001). In patients with detectable antibodies specific for acetylcholine receptors (Anti-AChR positive) the sRAGE concentration was 970.0 ± 90.2 compared to those without (seronegative) 670.6 ± 133.1 (vs. control; One-way ANOVA: p < 0.001; Post hoc analysis: Pos vs. Neg.: p = 0.418, Pos vs. control: p = 0.003, Neg. vs. control: p = 0.008). We next investigated the role of RAGE ligands in MG. The concentrations of RAGE ligands in patients with MG and controls were as follows: (HMGB1 [ng/ml] 1.7 ± 0.1 vs. 2.1 ± 0.2; p = 0.058; S100B [pg/ml] 22.5 ± 22.5 vs. 14.4 ± 9.2; p = 0.698; S100A8 [pg/ml] 107.0 ± 59.3 vs. 242.5 ± 103.6; p = 0.347; and AGE-CML [ng/ml] 1100.8 ± 175.1 vs. 1399.8 ± 132.8; p = 0.179).ConclusionsOur data suggest a role for the RAGE pathway in the pathophysiology of MG. Further studies are warranted to elucidate more about this immunological axis in patients with MG.     

Role of proinflammatory markers and NT-proBNP in patients with an implantable cardioverter-defibrillator and an electrical storm

BackgroundSeveral studies have attempted to identify risk factors for the development of an electrical storm (ES), which is defined as ⩾3 separate ventricular tachyarrhythmic (VT/VF) events, but in the majority of studies no triggers have been found. However, little is known about the role of inflammation and NT-proBNP in patients with ES. The aim of this study was therefore to assess the relationship of Interleukin-6 (IL-6), high-sensitivity C-reactive protein (hs-CRP) and NT-proBNP serum concentrations in ICD-patients with or without single spontaneous ventricular tachyarrhythmic events (VT/VF) and in ES.MethodsMarkers were determined in 51 patients without ICD-intervention, in 15 ICD-patients with single VT/VF-episodes during 9-months follow-up and in 20 ICD-patients with ES (blood sampling performed within 60 min after fulfilling ES criteria). VT/VF-episodes were analysed by stored ICD-electrograms.ResultsAll patients had idiopathic dilated cardiomyopathy (n = 23) or coronary artery disease (n = 63). Patients with ES revealed significantly higher mean serum concentrations of all markers (IL-6 15.19 ± 10.34 pg/mL, hs-CRP 20.12 ± 14.4 mg/L, NT-proBNP 4799 ± 4596 pg/mL) compared to baseline values of patients with single VT/VF-events during follow-up (IL-6 8.37 ± 5.8 pg/mL (p = 0.03), hs-CRP 4.7 ± 5.3 mg/dL (p < 0.001), NT-proBNP 1913 ± 2665 pg/mL (p = 0.04)) and compared to baseline values of ICD-patients without device intervention (IL-6 4.62 ± 3.66 pg/mL (p < 0.001), hs-CRP 4.1 ± 3.4 mg/L (p < 0.001), NT-proBNP 1461 ± 2281 pg/mL (p < 0.001)). In 9/20 patients presenting with ES (45%) baseline values were available. All markers were significantly higher during ES compared to event-free determination (IL-6 14.54 ± 10.43 vs. 7.03 ± 2.83 pg/mL (p = 0.04), hs-CRP 19.07 ± 16.07 vs. 6.5 ± 3.9 mg/L (p = 0.02), NT-proBNP 4218 ± 2561 vs. 2099 ± 1279 pg/mL (p = 0.03)).ConclusionsElectrical storm is associated with significantly elevated IL-6, hs-CRP and NT-proBNP serum concentrations in ICD-patients with structural heart disease. Thus, ES may be triggered by proinflammatory activity. Combined intraindividual elevation of determined markers might help to identify patients at risk of impending electrical storm.     

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.     

Different roles of zinc plus arachidonic acid on insulin sensitivity between high fructose- and high fat-fed rats

AimsThis study was to determine the effects of zinc plus arachidonic acid (ZA) treatment on the insulin action in the specific ZA target organs using hyperinsulinemic euglycemic clamp method.Main methods18 Sprague–Dawley rats weighing ~ 130 g were divided into 3 groups of 6 rats and treated them with 1) normal rat chow, 2) high fructose (60.0%) diet only, or 3) the same fructose diet plus drinking water containing 10 mg zinc plus 50 mg arachidonic acid (AA)/L. In a separate study, male Wistar rats weighing ~ 250 g were fed normal rat chow (n = 4) or high fat (66.5%) diet with drinking water containing zero (n = 9) or 10 mg AA plus 20 mg zinc /L (n = 9). After 4 week treatment, insulin action was assessed using the hyperinsulinemic eguglycemic clamp technique.Key findingsHigh fructose feeding impaired suppression of hepatic glucose output by insulin compared to controls during the clamp procedure (4.39 vs. 2.35 mg/kg/min; p < 0.05). However, ZA treatment in high fructose-fed rats showed a significant improvement of hepatic insulin sensitivity compared to non-treatment controls (4.39 vs. 2.18 mg/kg/min; p < 0.05). Glucose infusion rates in Wistar rats maintained on a high fat diet (HFD) were significantly lower compared to control rats (22.8 ± 1.3 vs. 31.9 ± 1.4 mg/kg/min; p < 0.05). ZA treatment significantly improved (~ 43%) peripheral tissue insulin sensitivity in HFD fed animals (26.7 ± 1.3 [n = 9] vs. 22.8 ± 1.3 mg/kg/min; p < 0.05).SignificanceThese data demonstrate that ZA treatment is effective in improving glucose utilization in hyperglycemic rats receiving either a high-fructose or a high-fat diet.     

Prevotella bivia as a source of lipopolysaccharide in the vagina

ObjectivesTo compare vaginal lipopolysaccharides (LPS) concentrations between patients with and without bacterial vaginosis (BV), to evaluate the correlation between Prevotella bivia colonization density and LPS concentration, and to determine the impact of LPS on loss of dopamine neurons (DA).MethodsVaginal washes obtained from patients with (n = 43) and without (n = 59) BV were tested for quantity of P. bivia cells using quantitative PCR and for concentrations of LPS using the Limulus Amebocyte Lysate gel clot method. Prevotella bivia, Gardnerella vaginalis and Escherichia coli sonicated cell extracts were also tested for LPS production. DA neuron cells obtained from embryonic day (E) 14.5 pregnant rats were exposed to fluid from eight vaginal washes; tyrosine hydrolase immunoreactive staining was applied for visualization and cell counts.ResultsThe median LPS concentrations were dramatically higher among patients who had symptoms of BV compared to those who did not have symptoms (3235.0 vs 46.4 EU/ml, respectively, P < 0.001); patients who had BV also had much higher colonization densities of P. bivia (0.06 ± 0.36 vs 5.4 ± 2.2 log₁₀ CFU/ml, respectively, P < 0.001).Prevotella bivia cell lysates resulted in a higher LPS concentration (10,713.0 ± 306.6 EU/ml) than either E. coli (4679.0 ± 585.3 EU/ml) or G. vaginalis (0.07 ± 0.01 EU/ml of LPS).The loss of DA neuron was 20–27% in cultures treated with vaginal washes from BV-negative patients and 58–97% in cultures treated with vaginal washes from patients with BV.ConclusionP. bivia produces high LPS concentration, which may create a toxic vaginal environment that damages DA neurons.     

Zinc and glycemic control: A meta-analysis of randomised placebo controlled supplementation trials in humans

BackgroundImpaired zinc metabolism is prominent in chronic disorders including cardiovascular disease and diabetes. Zinc has the potential to affect glucose homeostasis in animals and humans and hence impact the risk of type 2 diabetes mellitus.MethodsA systematic review and meta-analysis of randomised placebo controlled trials was conducted to determine the effect of zinc supplementation on fasting blood glucose, HbA1c, serum insulin and serum zinc concentrations. Relevant studies for inclusion were identified from a literature search of electronic databases up to July 2011.ResultsFourteen reports (n = 3978 subjects) were included in the meta-analysis. In the overall analysis, a small but statistically significant reduction in fasting glucose concentrations was observed (?0.19 ± 0.08 mmol/L, P = 0.013) after zinc supplementation. HbA1c tended to decrease in zinc-supplemented individuals (?0.64 ± 0.36%, P = 0.072). No significant effect was observed for serum insulin concentrations. Plasma zinc concentrations increased significantly following supplementation (+4.03 ± 0.81 μmol/L, P = 0.001). In secondary analyses of participants with chronic metabolic disease (types 1 and 2 diabetes mellitus, metabolic syndrome and obesity), zinc supplementation produced a greater reduction in glucose concentrations (?0.49 ± 0.11 mmol/L, P = 0.001) compared to the effect that was observed in healthy participants.ConclusionThe significant albeit modest reduction in glucose concentrations and tendency for a decrease in HbA1c following zinc supplementation suggest that zinc may contribute to the management of hyperglycemia in individuals with chronic metabolic disease.     

TNF-α -308 genotypes are associated with TNF-α and TGF-β₁ mRNA expression in blood leucocytes of humans

AimTumor necrosis factor α (TNF-α) influences the pathogenesis of lung-fibrosis and carcinogenesis in normal cells. Polymorphisms of this gene are suggested to be associated with susceptibility to lung-diseases. Additionally TNF-α is postulated to play a significant role in regulating. Transforming growth factor (TGF-β₁) expression Therefore we investigated if the TNF-α or TGF-β₁ gene expression level is different within the ?308 TNF-α genotypes.MethodsQuantitative Real-time PCR of TNF-α and TGF-β₁ was performed in 178 Germans. Calculations of expression were made with the 2^?ΔΔCT method. Detection of the ?308 promoter polymorphism of the TNF-α gene was performed by rapid capillary PCR with melting curve analysis.ResultsThe relative TNF-α mRNA expression revealed significant differences between the TNF-α ?308 homozygote wild-type G/G (0.00079 ± 0.00011; n = 113) and the heterozygote genotype G/A (0.0005 ± 0.00008; n = 52; p = 0.030) as well as between homozygote wild-type G/G and the homozygote mutant A/A (0.00029 ± 0.00009; n = 5; p = 0.004). The relative TGF-β mRNA expression showed, similar to TNF-α, the highest mRNA expression was seen within the TNF-α ?308 homozygote wild-types, while the lowest mRNA expression lay within the homozygote mutant-types.ConclusionOur findings suggest that the G-allele of TNF-α ?308 is associated with a significantly higher TNF-α mRNA expression compared to the A-allele and that this also reflects in TGF-β expression. Therefore we support the thesis that TGF-β is regulated by TNF-α.     

Relationship between zinc levels and plasma leptin in hemodialysis patients

Recent evidences suggested a possible relationship between zinc deficiency and leptin levels in pathogenesis of anorexia in chronic kidney disease. The present study addressed the relationship between zinc and leptin in hemodialysis (HD) patients.MethodsFifty HD patients (54.3 ± 12.7 years old, 62% men) were studied and compared to 21 healthy volunteers (50.7 ± 15.7 years old, 43% men). Biochemical data, serum zinc, plasma leptin, IL-6, TNF-α and C-Reactive Protein levels were determined. Anthropometric parameters, food intake and appetite score were also assessed.ResultsThe leptin levels were higher in HD patients (16.1 μg/mL (0.21–118.25) vs 6.0 μg/mL (0.50–23.10)) in healthy volunteers (p = 0.04), whereas serum zinc levels were lower (54.5 ± 16.3 μg/dL) compared to healthy volunteers (78.4 ± 9.4 μg/dL) (p = 0.0001). The plasma leptin was correlated negatively with plasma zinc (r = ?0.33; p = 0.007), energy (r = ?0.38; p = 0.002) and protein intake (r = ?0.34; p = 0.006) and, positively correlated with BMI (r = 0.54; p = 0.0001), % body fat (r = 0.70; p = 0.0001) and conicity index (r = 0.46; p = 0.001). Plasma zinc was associated with hemoglobin (r = 0.30; p = 0.04) and negatively associated with TNF-α (r = ?0.37; p = 0.002) and C-Reactive Protein (r = ?0.37; p = 0.004). There was no correlation among Zn, leptin and appetite score in these patients.ConclusionThis study showed that low plasma zinc levels are negatively associated with high leptin levels in HD patients.     

Trace elements in bipolar disorder

IntroductionTrace elements may play an important role in bipolar disorders. The objective of this study is to determine serum copper and zinc, blood lead and cadmium and urine lead, cadmium and thallium concentrations in patients diagnosed with bipolar disorders and to compare these levels with those of a healthy control group.Materials and methodsA total of 25 patients diagnosed with bipolar disorder and 29 healthy subjects participated in this study. Serum copper and zinc concentrations were measured using flame atomic absorption spectrometry; the blood lead and cadmium concentrations were measured by electrothermal atomization atomic absorption spectrometry with Zeeman background correction; urine lead, cadmium and thallium concentrations were measured by inductively coupled plasma mass spectrometry.ResultsMedian blood and urine lead and cadmium levels were significantly higher among the bipolar patients than among the control group: Blood lead (μg/dL): patient median: 3.00 (IQR: 1.40–4.20); control median (μg/dL): 2.20 (IQR: 0.90–3.00) p = 0.040. Blood cadmium (μg/L): patient median: 0.39 (IQR: 0.10–1.15); control median: 0.10 (IQR: 0.10–0.17) p < 0.001. The median of cadmium (μg/L) in patients who smoked (1.20 IQR: 0.44–2.30) was higher than that in non-smokers (0.12 IQR: 0.10–0.34) p < 0.001. There was a statistically significant increase (p = 0.001) in zinc levels among patients in the manic phase (mean 111.28, SD: 33.36 μg/dL) with respect to the control group (mean 86.07, SD: 12.39 μg/dL).ConclusionsThe results suggest that there could be higher levels of some toxic trace elements in the group of patients with bipolar disorder than in the healthy control group.     

Viscoelastic properties of human cerebellum using magnetic resonance elastography

BackgroundThe cerebellum has never been mechanically characterised, despite its physiological importance in the control of motion and the clinical prevalence of cerebellar pathologies. The aim of this study was to measure the linear viscoelastic properties of the cerebellum in human volunteers using Magnetic Resonance Elastography (MRE).MethodsCoronal plane brain 3D MRE data was performed on eight healthy adult volunteers, at 80 Hz, to compare the properties of cerebral and cerebellar tissues. The linear viscoelastic storage (G′) and loss moduli (G″) were estimated from the MRE wave images by solving the wave equation for propagation through an isotropic linear viscoelastic solid. Contributions of the compressional wave were removed via application of the curl-operator.ResultsThe storage modulus for the cerebellum was found to be significantly lower than that for the cerebrum, for both white and grey matter. Cerebrum: white matter (mean±SD) G′=2.41±0.23 kPa, grey matter G′=2.34±0.22 kPa; cerebellum: white matter, G′=1.85±0.18 kPa, grey matter G′=1.77±0.24 kPa; cerebrum vs cerebellum, p<0.001. For the viscous behaviour, there were differences in between regions and also by tissue type, with the white matter being more viscous than grey matter and the cerebrum more viscous than the cerebellum. Cerebrum: white matter G″=1.21±0.21 kPa, grey matter G″=1.11±0.03 kPa; cerebellum: white matter G″=1.1±0.23 kPa, grey matter G″=0.94±0.17 kPa.DiscussionThese data represent the first available data on the viscoelastic properties of cerebellum, which suggest that the cerebellum is less physically stiff than the cerebrum, possibly leading to a different response to mechanical loading. These data will be useful for modelling of the cerebellum for a range of purposes.     

Higher serum bone alkaline phosphatase as a predictor of mortality in male hemodialysis patients

AimsHigher serum alkaline phosphatase predicts lower mortality in chronic kidney disease and hemodialysis patients without liver dysfunction because it reflects high bone turnover. The purpose of our study was to compare the significance of serum bone alkaline phosphatase (BAP) with that of other bone markers in prediction of all-cause mortality(ACM) in male hemodialysis patients.Main methodsThe study was performed for 5 years. Serum BAP, intact osteocalcin (iOC), ß-CrossLaps (CTX), and intact parathyroid hormone (iPTH) were measured in 196 male hemodialysis patients without radiographic fracture. Their day-to-day variation during 5 consecutive days and diurnal variation were determined in 13 healthy males.Key findingsThe patients were divided into higher and lower groups based on serum levels of bone markers(mean ± SD: iPTH 218.6 ± 214.5 pg/ml, BAP 23.6 ± 12.2U/L, iOC 42.8 ± 45.2 ng/ml, CTX 1.71 ± 1.23 nmol/L BCE). In Kaplan–Meier analysis, the higher BAP group had significantly higher ACM than the lower BAP group (P = 0.013), whereas mortality did not differ between the higher and lower groups in other markers. Cox regression hazard analysis identified higher log BAP as a significant independent predictor [hazard ratio(HR) 8.32(95%CI:1.18–58.98)] for ACM after adjustment for various factors including pre-existing cardiovasucular disease, presence of DM. The significant association of mortality with serum BAP alone, in contrast with other markers including CTX [HR0.64 (95%CI:0.16–2.47)], iOC [HR0.97(95%CI:0.36–2.64)], iPTH [HR0.84(95%CI:0.44–1.60)],it may be due to the narrower day-to-day variation and the absence of diurnal variation in serum BAP compared to other markers.SignificanceHigher serum BAP may be a predictor of ACM in male hemodialysis patients.     

Serum zinc levels of cord blood: Relation to birth weight and gestational period

BackgroundZn-deficiency has been associated with numerous alterations during pregnancy including low birth weight; however, the research relating neonatal zinc status and birth weight has not produced reliable results.ObjectiveTo compare the serum Zn-levels of cord blood in healthy newborns and low birth weight newborns, and to assess a possible relationship between zinc concentration and neonatal birth weight and gestational age.Material and methods123 newborns divided in “study group” (n = 50) with <2500 g birth weight neonates and “control group” (n = 73) with ≥2500 g birth weight neonates were enrolled. Study group was subdivided according to gestational age in preterm (<37 weeks) and full-term (≥37 weeks). Serum cord blood samples were collected and the Zn-levels were analyzed using flame Atomic Absorption Spectrophotometry method and the result was expressed in μmol/L. The Zn-levels were compared between the groups (Mann–Whitney-U test) and the Zn-levels were correlated with the birth weight and gestational age (Spearman's rank correlations).ResultsStatistically significant low positive correlation between Zn-levels and birth weight (ρ = 0.283; p = 0.005) was found. No statistically significant difference between Zn-levels of study and control groups [17.00 ± 0.43 vs. 18.16 ± 0.32 (p = 0.053)] was found. Statistically significant low positive correlation between Zn-levels and gestational age (ρ = 0.351; p = 0.001) was found. No statistically significant difference between Zn-levels of preterm as compare to full-term newborns [16.33 ± 0.42 vs. 18.43 ± 0.93 (p = 0.079)] was found. Zn-level of preterm subgroup was significantly lower compared to control group (p = 0.001).ConclusionsDespite low birth weight preterm neonates had significantly lower serum zinc levels of cord blood than healthy term neonates, the correlation between cord blood zinc levels and birth weight and gestational age was lower. The results are not enough to relate the change in cord blood zinc concentration to the birth weight values or gestational period. In relation to complicated pregnancies, further studies regarding zinc levels in blood in our population are required.     

Aqueous humor nitric oxide in patients with central retinal vein occlusion

PurposeIt has been suggested that nitric oxide (NO) has a role in ischemic retinopathies. Since retinal ischemia may develop in retinal vein occlusion, we investigated the presence of nitric oxide in the pathogenesis of central retinal vein occlusion (CRVO).MethodsEighteen consecutive patients with CRVO were included in this study. Aqueous humor specimens were obtained within 21 days of diagnosis. Samples of aqueous humor were also collected from 20 control patients undergoing cataract surgery. For each sample after reduction of nitrate to nitrite with vanadium chloride (VCl₃), we used spectrophotometric method for simultaneous detection of nitrate and nitrite (NO_x).ResultsMean level of aqueous humor NO_x in CRVO and control group was 94.1 ± 23.2 μmol/l and 55.6 ± 11.0 μmol/l, respectively. The difference between two groups was statistically significant (p < 0.0001).ConclusionsOur results may support involvement of nitric oxide in the pathogenesis of CRVO.     

Nutrient concentrations in tidal creeks as indicators of the water quality role of mangrove wetlands in Southwest Florida

Coastal mangroves have the potential to improve the water quality of urban and rural runoff before it is discharged into adjacent coastal bays and oceans; but they also can be impaired by excessive pollutants from upstream. Nutrients (phosphorus and nitrogen), salinity, and other water quality parameters were measured in five mangrove tidal creeks in different hydrogeomorphic and urbanization settings during high and low tides over a calendar year of wet (June and August 2015) and dry (February and April 2016) seasons in the Greater Naples Bay area in Southwest Florida, USA. Nutrient concentrations (ave. ± std error) in the tidal creeks were 0.055 ± 0.008 mg-P/L for total phosphorus (TP) and 0.610 ± 0.020 mg-N/L for total nitrogen (TN), with an average N:P ratio of 11.4:1. Average wet season TP (0.075 ± 0.010 mg-P/L) was significantly higher than the dry season TP (0.033 ± 0.003 mg-P/L; p < 0.01, f = 15.17, f_crit = 3.89) and the average wet season TN (0.75 ± 0.03 mg-N/L) was significantly higher than dry season TN (0.52 ± 0.02 mg/L; p < 0.01, f = 64.14, f_crit = 3.89), suggesting that urban stormwater runoff is directly or indirectly affecting the nutrient conditions in these mangroves. Significant differences in nutrient concentrations between low tide and high tide were not found for either TP (p = 0.43, f = .63, f_crit = 3.88) or TN (p = 0.20, f = 1.66, f_crit = 3.89). These differences were confirmed by a PCA and cluster analyses, which found differences to be seasonal. We could not conclude from these results whether these five mangrove wetlands were sources nor sinks of nutrients based simply on the measurement of nutrient concentrations. But we illustrated that nutrient concentrations were indicators of the mangroves’ hydrogeomorphic settings, their tidal fluxes from Naples Bay, and the Bay's upstream watersheds, and less by direct urban runoff.     

Role of high-fat diet in regulation of gene expression of drug metabolizing enzymes and transporters

AimsLate phase ischemic preconditioning (LPC) protects the heart against ischemia–reperfusion (I/R) injury. However, its effect on myocardial tissue oxygenation and related mechanism(s) is unknown. The aim of the current study is to determine whether LPC attenuates post-ischemic myocardial tissue hyperoxygenation through preserving mitochondrial oxygen metabolism.Main methodsC57BL/6 mice were subjected to 30 min coronary ligation followed by 60 min or 24 h reperfusion with or without LPC (3 cycles of 5 min I/5 min R): Sham, LPC, I/R, and LPC + I/R group. Myocardial tissue Po₂ and redox status were measured with electron paramagnetic resonance (EPR) spectroscopy.Key findingsUpon reperfusion, tissue Po₂ rose significantly above the pre-ischemic level in the I/R mice (23.1 ± 2.2 vs. 12.6 ± 1.3 mm Hg, p < 0.01). This hyperoxygenation was attenuated by LPC in the LPC + I/R mice (11.9 ± 2.0 mm Hg, p < 0.01). Activities of NADH dehydrogenase (NADH-DH), succinate-cytochrome c reductase (SCR) and cytochrome c oxidase (CcO) were preserved or increased in the LPC group, significantly reduced in the I/R group, and conserved in the LPC + I/R group. Manganese superoxide dismutase (Mn-SOD) protein expression was increased by LPC in the LPC and LPC + I/R mice compared to that in the Sham control (1.24 ± 0.01 and 1.23 ± 0.01, p < 0.05). Tissue redox status was shifted to the oxidizing state with I/R (0.0268 ± 0.0016/min) and was corrected by LPC in the LPC + I/R mice (0.0379 ± 0.0023/min). Finally, LPC reduced the infarct size in the LPC + I/R mice (10.5 ± 0.4% vs. 33.3 ± 0.6%, p < 0.05).SignificanceThus, LPC preserved mitochondrial oxygen metabolism, attenuated post-ischemic myocardial tissue hyperoxygenation, and reduced I/R injury.     

Effect of Metformin Therapy on Vitamin D and Vitamin B12 Levels in Patients with Type 2 Diabetes Mellitus

ObjectiveTo determine the effect of metformin on 25-hydroxyvitamin D [25(OH)D] and vitamin B₁₂ levels in patients with type 2 diabetes mellitus.MethodsWe performed a retrospective review of medical records of patients treated between 2003 and 2009 at Loyola University Medical Center, Maywood, Illinois, in both ambulatory primary care and endocrinology clinics. The study cohort consisted of 706 patients with type 2 diabetes mellitus who were 20 to 93 years old (mean age, 63 ± 13) and had a mean body mass index of 33.1 kg/m². Of these patients, 42% were treated with metformin, and 34% had been diagnosed with osteoporosis or osteopenia.ResultsPatients taking metformin had statistically significant lower vitamin B₁₂ levels than those not receiving metformin (P < .0001; 95% confidence interval [CI] = − 220 to − 84 pg/mL). No statistically significant difference was found between users and nonusers of metformin in regard to 25(OH)D levels when adjusted for variables (P = .297; 95% CI for mean difference = − 0.7 to 2.2 ng/mL). Metformin use did not adversely affect successful treatment of vitamin D deficiency in this patient population as a whole, nor did it affect the subgroup with osteoporosis (P = .956). The patients with osteoporosis had statistically significant lower baseline 25(OH)D levels in comparison with those without osteoporosis, when adjustments were made for all variables (P = .003; 95% CI = 0.7 to 3.5 ng/ mL).ConclusionThis study confirms the higher prevalence of vitamin B₁₂ deficiency in metformin-treated patients with type 2 diabetes than in those not treated with metformin. This study also suggests that vitamin D deficiency is not a clinical concern among metformin-treated patients with type 2 diabetes and that metformin does not negatively affect treatment of vitamin D deficiency in these patients. (Endocr Pract. 2012;18:179–184)     

Postoperative acute kidney injury is associated with hemoglobinemia and an enhanced oxidative stress response

Acute kidney injury (AKI) frequently afflicts patients undergoing cardiopulmonary bypass and independently predicts death. Both hemoglobinemia and myoglobinemia are independent predictors of postoperative AKI. Release of free hemeproteins into the circulation is known to cause oxidative injury to the kidneys. This study tested the hypothesis that postoperative AKI is associated with both enhanced intraoperative hemeprotein release and increased lipid peroxidation assessed by measuring F₂-isoprostanes and isofurans. In a case–control study nested within an ongoing randomized trial of perioperative statin treatment and AKI, we compared levels of F₂-isoprostanes and isofurans with plasma levels of free hemoglobin and myoglobin in 10 cardiac surgery AKI patients to those of 10 risk-matched controls. Peak plasma free hemoglobin concentrations were significantly higher in AKI subjects (289.0 ± 37.8 versus 104.4 ± 36.5 mg/dl, P = 0.01), whereas plasma myoglobin concentrations were similar between groups. The change in plasma F₂-isoprostane and isofuran levels (repeated-measures ANOVA, P = 0.02 and P = 0.001, respectively) as well as the change in urine isofuran levels (P = 0.04) was significantly greater in AKI subjects. In addition, change in peak plasma isofuran levels correlated not only with peak free plasma hemoglobin concentrations (r² = 0.39, P = 0.001) but also with peak change in serum creatinine (r² = 0.20, P = 0.01). Postoperative AKI is associated with both enhanced intraoperative hemeprotein release and enhanced lipid peroxidation. The correlations among hemoglobinemia, lipid peroxidation, and AKI indicate a potential role for hemeprotein-induced oxidative damage in the pathogenesis of postoperative AKI.     

Effect of pain location on spatial reorganisation of muscle activity

IntroductionWe aimed to determine whether the changes in muscle activity (in terms of both gross electromyography (EMG) and motor unit (MU) discharge characteristics) observed during pain are spatially organized with respect to pain location within a muscle which is the main contributor of the task.MethodsSurface and fine-wire EMG was recorded during matched low-force isometric plantarflexion from soleus (from four quadrants with fine-wire EMG and from the medial/lateral sides with surface EMG), both gastrocnemii heads, peroneus longus, and tibialis anterior. Four conditions were tested: two control conditions that each preceded contractions with pain induced in either the lateral (Pain_L) or medial (Pain_M) side of soleus.ResultsNeither the presence (p = 0.28) nor location (p = 0.19) of pain significantly altered gross muscle activity of any location (lateral/medial side of soleus, gastrocnemii, peroneus longus and tibialis anterior). Group data from 196 MUs show redistribution of MU activity throughout the four quadrants of soleus, irrespective of pain location. The significant decrease of MU discharge rate during pain (p < 0.0001; Pain_L: 7.3 ± 0.9–6.9 ± 1.1 Hz, Pain_M: 7.0 ± 1.1 to 6.6 ± 1.1 Hz) was similar for all quadrants of the soleus (p = 0.43), regardless of the pain location (p = 0.98). There was large inter-participant variation in respect to the characteristics of the altered MU discharge with pain.ConclusionResults from both surface and fine-wire EMG recordings do not support the hypothesis that muscle activity is reorganized in a simple systematic manner with respect to pain location.     

Serum interleukin-6 concentration reflects the extent of asymptomatic left ventricular dysfunction and predicts progression to heart failure in patients with stable coronary artery disease

BackgroundLeft ventricular ejection fraction (LVEF) remains one of the strongest predictors of long-term prognosis in patients with stable coronary artery disease (CAD). Asymptomatic left ventricular systolic dysfunction (LVSD) often precedes clinically overt heart failure (HF) and is an area of extensive research nowadays. We studied the association between serum IL-6 concentrations and the extent of LV dysfunction in patients with asymptomatic LVSD. We aimed to investigate the diagnostic value of serum IL-6 concentrations in predicting the risk of progression to HF. Seventy-one patients entered the study and were divided into three groups based on LVEF: group 1 – patients with LVEF <30% (N = 7), group 2 – patients with LVEF 30–50% (N = 37) and group 3 – patients with LVEF >50% (N = 27).ResultsDemographics were similar in all three groups. IL-6 concentration was the highest in group 1 (median 8.6 pg/mL) and the lowest in group 3 (median 2.6 pg/mL), whereas IL-6 concentration in group 2 was intermediate (median 3.7 pg/mL) (P = 0.002). We found a significant, inverse correlation between IL-6 concentration and ejection fraction. During 18-month follow-up clinically overt HF developed in 71.4% of patients in group 1 and in 37.5% of patients in group 2. None of the patients in group 3 manifested HF symptoms (P < 0.001). ROC analysis revealed high diagnostic value of serum IL-6 and LVEF in predicting progression to HF. We also found a strong, inverse correlation between IL-6 and the time of progression to HF.ConclusionsThere is a strong correlation between IL-6 and the extent of asymptomatic LVSD in patients with documented CAD. Elevated IL-6 concentrations preceded progression to clinically overt HF. Moreover, the higher the IL-6 concentration the earlier the manifestation of HF symptoms.