The voltage-dependent anion channel (VDAC) mediates trafficking of small molecules and ions across the eukaryotic outer mitochondrial membrane. VDAC also interacts with antiapoptotic proteins from ...the Bcl-2 family, and this interaction inhibits release of apoptogenic proteins from the mitochondrion. We present the nuclear magnetic resonance (NMR) solution structure of recombinant human VDAC-1 reconstituted in detergent micelles. It forms a 19-stranded β barrel with the first and last strand parallel. The hydrophobic outside perimeter of the barrel is covered by detergent molecules in a beltlike fashion. In the presence of cholesterol, recombinant VDAC-1 can form voltage-gated channels in phospholipid bilayers similar to those of the native protein. NMR measurements revealed the binding sites of VDAC-1 for the Bcl-2 protein Bcl-xL, for reduced β-nicotinamide adenine dinucleotide, and for cholesterol. Bcl-xL interacts with the VDAC barrel laterally at strands 17 and 18.
Three commercial dilute Russell's viper venom time (DRVVT) kits were evaluated at four UK centres experienced at performing lupus anticoagulant (LA) tests. Each centre established a normal reference ...range for the DRVVT ratio calculated against local pooled normal plasma from 20 healthy normal subjects. Plasma from LA-positive patients and LA-negative thrombophilia patients was also tested. DRVVT ratios and the degree of correction were assessed in a variety of ways to reflect not only the UK national Guidelines, but also the manufacturers' recommendations. The reference range data showed a normal distribution in each case, but considerable variation in the mean and SD between the centres and reagents, with the mean +2SD value ranging from 1.06 to 1.19. The use of an arbitrary DRVVT ratio of < 1.1 as the cut-off value for normality, which is applied in many laboratories, is therefore inappropriate. Although no single kit had a clear overall advantage in terms of sensitivity and specificity, the way in which the screen and confirmation data were analysed had a major impact on the interpretation of the results. A data analysis method employing a mean plus two standard deviations (SDs) cut-off for normality, and judgement regarding confirmation of LA based on a percentage correction of DRVVT ratio, was the simplest and most consistent, with overall sensitivity and specificity values of 81% and 94%, respectively, for uncomplicated LA-positive and LA-negative thrombophilia samples. We conclude that the 1991 BSCH Guidelines are in need of revision, each laboratory should establish its own normal reference range for the DRVVT ratio and a common method should be used for calculating the degree of correction with confirmation reagents, so that LA results can be correctly interpreted between laboratories. Standardizing DRVVT interpretation in this way should improve the consistency of LA detection.
We have investigated the effects of purified IgG fractions from plasma containing the lupus anticoagulant (LAC) and/or IgG anticardiolipin antibody (ACA) on the degradation of factor Va by an ...activated protein C-protein S complex. Plasma samples from 10 patients were studied. LAC was detected by a Russell's Viper venom technique. ACA was determined by ELISA. IgG fractions were obtained from each plasma sample by protein A-Sepharose fractionation. This fraction was shown to exhibit ACA/LAC activity. Using purified activated protein C (APC), protein S and phosphatidylserine/phosphatidylcholine, factor Va degradation was assessed in the presence and absence of IgG fractions from LAC/ACA containing plasmas. After 2 min incubation the mean factor Va degradation by APC and protein S in the presence of IgG LAC/ACA fractions was 14% compared with 52% with normal IgG. A similar effect was seen when phospholipid was substituted by washed freeze-thawed platelets. Experiments employing varying concentrations of protein S and phospholipid revealed marked differences in respect of the inhibitory specificity of the different antiphospholipid antibodies. These results indicate that antiphospholipid antibodies have an inhibitory effect on the activated protein C/protein S complex and provide some explanation for a relationship between antiphospholipid antibodies and thrombosis.
This study sought to investigate the effects of a multistrain probiotic on body composition, regional adiposity, and a series of associated metabolic health outcomes. Female health care workers ...employed on a rotating-shift schedule (n = 41) completed baseline anthropometric assessments; a fasted blood draw; questionnaires to assess anxiety, depression (Hospital Anxiety and Depression Scale), and fatigue (Chalder Fatigue Survey); and an exercise fatigue test. Identical post-tests occurred following 6 weeks of daily supplementation with placebo (PLA) or probiotics (2.5 × 10
9
CFU/g) containing 9 bacterial strains (PRO; Ecologic Barrier) combined with a prebiotic carrier matrix. PRO attenuated fat mass increases (change (Δ), 0.14 kg; confidence interval (CI) –0.46 to 0.75 kg) compared with PLA (Δ, 0.79 kg; CI 0.03–1.54 kg), whereas modest reductions in visceral adiposity resulted for both PRO and PLA. Metabolic biomarkers (total cholesterol, high-density lipoprotein, glucose, adiponectin, C-reactive protein, interleukin-6, leptin) were not influenced by either treatment (p > 0.05). Nonsignificant, but potentially clinically relevant, improvements in anxiety (Δ, –2.3 ± 2.63) and fatigue (Δ, –4.8 ± 5.5) were observed with PRO; exercise performance was unaffected. Results indicate a potential protective effect of probiotics against fat mass gain. Probiotics may alleviate anxiety and fatigue in shift-working females.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The activated protein C resistance (APC‐R) ratios in 50 patients with steady state homozygous sickle cell (SS) disease and 59 healthy AA controls was measured. There was a significant reduction in ...median APC‐R ratio in sickle cell disease compared to controls. This reduction in APC‐R ratio was not explained by (1) the presence of the factor V Leiden, found in only one of 165 patients with SS disease including those tested for APC‐R, or (2) the presence of lupus anticoagulants. However, the raised levels of factor VIIIC in SS patients in this study may be contributing to increased resistance to APC, which in turn may contribute to the vaso‐occlusive complications of SS disease.
The interrelationships between fibrinogen, von Willebrand factor, a marker of vascular endothelial cell damage, and serum lipids were explored in well-characterised subjects with insulin-dependent ...diabetes mellitus. The 2091 subjects were enrolled into a cross-sectional, clinic-based study of complications, from 16 European countries: the EURODIAB IDDM Complications study. The anticipated significant relationships between both plasma fibrinogen and plasma von Willebrand factor concentrations and age and glycaemic control, and between fibrinogen and body mass index, were noted. Fibrinogen, adjusted for age and glycated haemoglobin concentration, was also related to smoking habits and was higher in the quartiles with highest systolic and diastolic blood pressures. There was a clustering of vascular risk factors, with a positive relationship between plasma fibrinogen and serum triglyceride concentrations in both genders and between fibrinogen and total cholesterol in males. An inverse relationship between fibrinogen and high density lipoprotein cholesterol was also apparent in males. A prominent feature was a positive relationship between both fibrinogen and von Willebrand factor and albumin excretion rate (p < 0.001 and p < 0.003 respectively) in those with retinopathy but not in those without this complication. In view of previous observations on blood pressure and albuminuria in these subjects the findings are consistent with the hypothesis that microalbuminuria and increased plasma von Willebrand factor are due to endothelial cell perturbation in response to mildly raised blood pressure in subjects with retinopathy. Fibrinogen may also contribute to microvascular disease and its relationships to lipid vascular risk factors suggest a possible pathogenic role in arterial disease in diabetes.
Kainic acid, the flagship member of the kainoid family of natural neurochemicals, is a widely used neuropharmacological agent that helped unravel the key role of ionotropic glutamate receptors, ...including the kainate receptor, in the central nervous system. Worldwide shortages of this seaweed natural product in the year 2000 prompted numerous chemical syntheses, including scalable preparations with as few as six‐steps. Herein we report the discovery and characterization of the concise two‐enzyme biosynthetic pathway to kainic acid from l‐glutamic acid and dimethylallyl pyrophosphate in red macroalgae and show that the biosynthetic genes are co‐clustered in genomes of Digenea simplex and Palmaria palmata. Moreover, we applied a key biosynthetic α‐ketoglutarate‐dependent dioxygenase enzyme in a biotransformation methodology to efficiently construct kainic acid on the gram scale. This study establishes both the feasibility of mining seaweed genomes for their biotechnological prowess.
Kainic acid is a marine natural product that has been used as an anthelmintic agent for centuries and, more recently, a neurological tool. Using a genomic sequencing approach, the genes responsible for the biosynthesis of kainic acid were discovered in two different seaweeds. In vitro characterization validated enzymatic activity and enabled gram‐scale production of kainic acid using a biotransformation approach.
ABSTRACTThe current study sought to evaluate the effects of post-exercise ingestion of a high molecular weight glucose polymer solution (HMW) compared to an isocaloric low molecular weight solution ...(LMW) or placebo (PLA) on subsequent cycling performance in female athletes. In a randomized, double-blind, placebo-controlled, cross-over design, 10 competitive female cyclists (Mean ± SD; Age = 25.7 ± 5.0 yrs; VO2peak = 49.7 ± 4.3 mlBULLET OPERATORkgBULLET OPERATORmin) completed three testing sessions separated by 7-10 days. Visits consisted of a ride-to-exhaustion (RTE) at 75% VO2peak, followed by immediate consumption of 700 mL containing either1.2 gBULLET OPERATORkg LMW (maltodextrin/dextrose/fructose); 1.2 gBULLET OPERATORkg HMW (Vitargo®); or 0.066 gBULLET OPERATORkg PLA (noncaloric flavoring). After 2 hours rest, participants performed a 15-minute time-trial (TT). Respiratory exchange ratio (RER) was assessed via indirect calorimetry during exercise. Total body water (TBW) was measured using bioelectrical impedance to assess fluid balance. When covaried for estrogen, there was no treatment effect on distance (km; p=0.632) or power output (watts; p=0.974) during the 15-minute TT. RER was not significantly different during the LMW and HWM TTs (p>0.999), but both were significantly higher than PLA (p=0.039, p=0.001, respectively). Changes in TBW pre- to post-exercise were not significantly different between trials (p=0.777). Despite benefits of HMW on cycling performance previously reported in males, current results demonstrate no ergogenic effect of HMW or LMW in females. Sex differences in substrate utilization may account for the discrepancy, and further research involving performance nutrition for female athletes is merited.
Three-dimensional (3D) body scanner technology for body composition assessment is expanding. The aim of this study was to assess the validity of a 3D body scanner. One hundred and ninety-four ...participants (43% male; age: 23.52 ± 5.47 years; body mass index: 23.98 ± 3.24 kg·m
−2
) were measured using 3D scanner and a 4-compartment (4C) model utilizing dual-energy X-ray absorptiometry (DXA), air displacement plethysmography, and bioelectrical impedance spectroscopy. Dependent t tests, validity statistics including total error (TE), standard error of the estimate, constant error, and Bland–Altman analyses were utilized. Compared with 4C, 3D scanner fat mass (FM) mean difference (MD; 3D−4C): 2.66 kg ± 3.32 kg and percent body fat (%BF) (MD: 4.13% ± 5.36%) were significantly (p < 0.001) over-predicted; fat free mass (FFM) was significantly underpredicted (MD: −3.15 kg ± 4.75 kg; p < 0.001). 3D demonstrated poor validity indicated by TE (%BF: 5.61%; FM: 4.50 kg; FFM: 5.69 kg). In contrast, there were no significant differences between 3D and DXA measures; 3D scanner demonstrated acceptable measurement for %BF (TE: 4.25%), FM (TE: 2.92 kg), and lean mass (TE: 3.86 kg). Compared with the 4C criterion, high TE values indicated 3D estimates were not valid. In contrast, 3D estimates produced acceptable measurement agreement when compared with DXA; an average overestimation of %BF by 5.31% (vs. 4C) and 4.20% (vs. DXA) may be expected.
Novelty:
3D body composition estimates are not valid compared with the 4-C criterion model.
3D estimates appeared to be more valid in females, compared with males.
When compared with DXA, 3D estimates were acceptable.
Celotno besedilo
Dostopno za:
DOBA, FSPLJ, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The aim of this study was to confirm reports of low protein C (PC) and S (PS) concentrations in steady‐state patients with homozygous sickle cell (SS) disease when compared to a racially matched ...normal haemoglobin (AA) control group and to examine the mechanisms of this reduction with respect to hepatic function, coagulation activation and haematological indices.
In 36 SS patients and 35 AA race‐matched controls PC (functional and immunoreactive), PS (free and total) were measured. C4B binding protein (C4B) was assessed by immunoelectrophoresis and D‐dimer by ELISA. Hepatic function was assessed by prothrombin (PT) time (49 SS, 64 AA), factor V (34 SS, 36 AA) and factor VII concentrations (28 SS, 29 AA). Proteins induced in vitamin K absence or antagonism (PIVKA) were sought in 12 SS's. The relationship between PC, PS and total bilirubin, haemoglobin (Hb) F and reticulocyte count was also assessed.
PC, PS and C4B were lower in SS disease. SS patients had longer PT times, and lower factor V and VII concentrations in comparison to AA controls. PC (functional and immunoreactive) and free PS correlated with PT. Within SS genotype PT correlated negatively with factor V and factor VII. Factor V and VII were positively correlated. PIVKAs were not detected. There was no correlation between PC, PS and D‐dimer, haemolytic rate or Hb F concentration.
Prolongation of PT time, low factor V and VII suggest that hepatic dysfunction, rather than coagulation activation or haemolytic rate, accounts for the reduced concentrations of PC and PS in steady‐state SS disease. The absence of PIVKAs suggests a hepatocellular problem.
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