Interleukin-1 receptor antagonist, interleukin-2 receptor alpha subunit and amyotrophic lateral sclerosis.

BACKGROUND AND PURPOSE: To clarify the causal associations of interleukin-1 receptor antagonist (IL-1ra) and interleukin-2 receptor alpha subunit (IL-2rα) with the risk of amyotrophic lateral sclerosis (ALS). METHODS: A two-sample Mendelian randomization study design was employed. Single-nucleotide polymorphisms associated with IL-1ra (n = 2) and IL-2rα (n = 1) at the genome-wide significance level were used as unbiased instrumental variables. Summary-level data for ALS were obtained from Project MinE, an international collaboration consortium with 12 577 ALS cases and 23 475 controls of European descent. RESULTS: Genetic predisposition to higher levels of IL-1ra was significantly associated with lower odds of ALS. For a 1-SD increase of circulating IL-1ra levels, the odds ratio of ALS was 0.64 (95% confidence intervals, 0.46-0.88; P = 0.005). There was a borderline inverse association between IL-2rα levels and ALS (odds ratio, 0.91; 95% confidence intervals, 0.83-1.00; P = 0.058). CONCLUSIONS: Interleukin-1 receptor antagonist levels were inversely associated with ALS, suggesting that interleukin-1 inhibitors may lower the risk of this always fatal disease. The role of IL-2rα levels in ALS needs further verification in causal inference studies with larger sample sizes.

Unique Access to u-Channel Physics: Exclusive Backward-Angle Omega Meson Electroproduction.

Backward-angle meson electroproduction above the resonance region, which was previously ignored, is anticipated to offer unique access to the three quark plus sea component of the nucleon wave function. In this Letter, we present the first complete separation of the four electromagnetic structure functions above the resonance region in exclusive ω electroproduction off the proton, ep→e^{'}pω, at central Q^{2} values of 1.60, 2.45 GeV^{2}, at W=2.21 GeV. The results of our pioneering -u≈-u_{min} study demonstrate the existence of a unanticipated backward-angle cross section peak and the feasibility of full L/T/LT/TT separations in this never explored kinematic territory. At Q^{2}=2.45 GeV^{2}, the observed dominance of σ_{T} over σ_{L}, is qualitatively consistent with the collinear QCD description in the near-backward regime, in which the scattering amplitude factorizes into a hard subprocess amplitude and baryon to meson transition distribution amplitudes: universal nonperturbative objects only accessible through backward-angle kinematics.

Activation of old carbon by erosion of coastal and subsea permafrost in Arctic Siberia.

The future trajectory of greenhouse gas concentrations depends on interactions between climate and the biogeosphere. Thawing of Arctic permafrost could release significant amounts of carbon into the atmosphere in this century. Ancient Ice Complex deposits outcropping along the ~7,000-kilometre-long coastline of the East Siberian Arctic Shelf (ESAS), and associated shallow subsea permafrost, are two large pools of permafrost carbon, yet their vulnerabilities towards thawing and decomposition are largely unknown. Recent Arctic warming is stronger than has been predicted by several degrees, and is particularly pronounced over the coastal ESAS region. There is thus a pressing need to improve our understanding of the links between permafrost carbon and climate in this relatively inaccessible region. Here we show that extensive release of carbon from these Ice Complex deposits dominates (57 ± 2 per cent) the sedimentary carbon budget of the ESAS, the world's largest continental shelf, overwhelming the marine and topsoil terrestrial components. Inverse modelling of the dual-carbon isotope composition of organic carbon accumulating in ESAS surface sediments, using Monte Carlo simulations to account for uncertainties, suggests that 44 ± 10 teragrams of old carbon is activated annually from Ice Complex permafrost, an order of magnitude more than has been suggested by previous studies. We estimate that about two-thirds (66 ± 16 per cent) of this old carbon escapes to the atmosphere as carbon dioxide, with the remainder being re-buried in shelf sediments. Thermal collapse and erosion of these carbon-rich Pleistocene coastline and seafloor deposits may accelerate with Arctic amplification of climate warming.

Development of knowledge tests for multi-disciplinary emergency training: a review and an example.

BACKGROUND: The literature is sparse on written test development in a post-graduate multi-disciplinary setting. Developing and evaluating knowledge tests for use in multi-disciplinary post-graduate training is challenging. The objective of this study was to describe the process of developing and evaluating a multiple-choice question (MCQ) test for use in a multi-disciplinary training program in obstetric-anesthesia emergencies. METHODS: A multi-disciplinary working committee with 12 members representing six professional healthcare groups and another 28 participants were involved. Recurrent revisions of the MCQ items were undertaken followed by a statistical analysis. The MCQ items were developed stepwise, including decisions on aims and content, followed by testing for face and content validity, construct validity, item-total correlation, and reliability. RESULTS: To obtain acceptable content validity, 40 out of originally 50 items were included in the final MCQ test. The MCQ test was able to distinguish between levels of competence, and good construct validity was indicated by a significant difference in the mean score between consultants and first-year trainees, as well as between first-year trainees and medical and midwifery students. Evaluation of the item-total correlation analysis in the 40 items set revealed that 11 items needed re-evaluation, four of which addressed content issues in local clinical guidelines. A Cronbach's alpha of 0.83 for reliability was found, which is acceptable. CONCLUSION: Content and construct validity and reliability were acceptable. The presented template for the development of this MCQ test could be useful to others when developing knowledge tests and may enhance the overall quality of test development.

CYP7B1: novel mutations and magnetic resonance spectroscopy abnormalities in hereditary spastic paraplegia type 5A.

UNLABELLED: The SPG5A subtype of Hereditary Spastic Paraplegia (HSP) is a rare autosomal recessive neurodegenerative disorder caused by mutations in the CYP7B1 gene, which encodes a steroid cytochrome P450 7α-hydroxylase. This enzyme provides the primary metabolic route for neurosteroids. Clinically, SPG5A has been characterized as a pure form of HSP with a variable age of onset, but recently a broader spectrum of phenotypes has been described. OBJECTIVE: This study characterizes four unrelated SPG5A patients through clinical evaluation. METHODS: The investigations included blood biochemistry, electrophysiology, brain MRI and MR spectroscopy. RESULTS: One patient had saccadic pursuit eye movements in addition to a pure HSP phenotype. Motor evoked potential (MEP) examinations revealed prolonged central conduction time. MRI of the brain showed white matter hyperintensities (WMH) in one patient. MRS showed elevated mI/Cr ratio in white matter in two patients; in the one patient with WMH and in one patient with normal MRI. Four novel mutations were identified; one frameshift (c.509 delT p.L170fs), one premature stop codon (c.334 C>T p.R112X), one amino acid changing (c.440 G>A p.G147D) and one duplication (c.945_947 dupGGC p.A316AA). CONCLUSION: SPG5A could be characterized as a predominantly pure HSP. MRS showing elevated mI/Cr ratio in the white matter may be indicative of SPG5A.

Blood lead concentrations in exposed forecourt attendants and taxi drivers in parts of South Africa.

BACKGROUND: Leaded fuel was banned in South Africa in 2006, in order to improve human health and reduce environmental pollution. Lead (Pb) has been suggested to contribute to the development of neurodegenerative disorders, and the role of respiratory exposure to Pb from petrol fumes should not be neglected in this context. In addition to Pb, petrol contains various harmful chemicals including other neurotoxic metals and hydrocarbons. OBJECTIVES AND METHODS: Here, we investigated concentrations of Pb and other metals in blood from petrol station forecourt attendants (n = 38), taxi drivers (n = 21), and unexposed controls (n = 36). Taxi drivers and forecourt attendants were divided into three groups each, based on number of years worked. A questionnaire was designed to investigate the health status of the participants. Blood samples were collected by medical professionals and analyzed for metal concentrations by ICP-MS. RESULTS: A positive correlation between number of years worked and Pb blood concentrations was found. The highest Pb concentration (60.2 µg/L) was observed in a forecourt attendant who had worked 11-20 years, and the average Pb concentration in this group (24.5 µg/L) was significantly (p < 0.05) higher than in forecourt attendants who had worked 2-5 years (10.4 µg/L). Some individuals had elevated concentrations of manganese, arsenic, cadmium, chromium and cobalt, yet not significantly elevated at the group level. The blood levels of arsenic appeared to be related to smoking. Mood swings, dizziness, headaches and tiredness were reported by the workers. CONCLUSION: Blood Pb concentrations in petrol station forecourt attendants and taxi drivers exposed to leaded petrol are elevated and correlate to exposure time. A health monitoring program should be erected for all individuals working in these industries, and preventive measures should be implemented to eliminate metal exposure from petrol.

Prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) in a middle-aged population with overweight and normal liver enzymes, and diagnostic accuracy of noninvasive proxies.

The prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is increasing at an alarming rate. Elevated liver enzymes are a primary reason to refer patients for further testing. However, liver enzymes within the normal range do not exclude the presence of MASLD. We examined the prevalence of MASLD in a middle-aged population with overweight and normal liver enzymes. In addition, we examined the accuracy of 4 sets of noninvasive proxies for MASLD. We included 1017 participants from the Netherlands epidemiology of obesity cohort study with body mass index ≥25 kg/m2 and liver enzymes (asparate aminotransferase, alanine aminotransferase, gamma-glutamyltranspeptidase) within normal range. The diagnostic accuracy of biomarker scores (fatty liver index, liver fat score [LFS], STEATO-ELSA, and hepatic steatosis index) was determined against elevated hepatic triglyceride content measured by 1proton magnetic resonance spectroscopy. Participants (mean age 56 years, 49% women), had a median body mass index of 29.6 kg/m2 and a median hepatic triglyceride content of 4.4%. MASLD was present in 42% of participants and was more common in men than women, with respectively 47% and 36% being affected. The LFS showed the highest accuracy with an area under the curve of 0.72. We identified metabolic syndrome as the prime predictor for MASLD with an odds ratio of 2.95 (95% confidence interval 2.20-3.98). The prevalence of MASLD in middle-aged men and women with overweight and liver enzymes within the normal range is over 40%. LFS showed the highest accuracy to detect MASLD, but, overall, biomarker scores performed relatively poor. The presence of metabolic syndrome was the prime predictor of MASLD.

Inclusion body myositis in Alzheimer's disease.

BACKGROUND: The prevalence of Alzheimer's disease is increasing. Could findings of similar deposits in brain and muscle tissue explain this increase? The purpose of this report is to illustrate that Alzheimer's disease and inclusion body myositis may share a common aetiology. RESULTS: We present a case where Alzheimer's disease and inclusion body myositis coexist in the same patient. Amyloid-beta deposition and the presence of phosphorylated tau protein have been noted in brain tissue and in muscle biopsy from patients with these disorders. METHODS: Electrophysiological methods are needed for proper diagnosis of this brain and muscle disorder. Recent data on deposit structures in both conditions may indicate an environmental aetiology for Alzheimer's disease and inclusion body myositis. CONCLUSION: By combining electrophysiological methods with muscle biopsy in cases of Alzheimer's disease, the possible aetiological connection between simultaneous affection of both muscle and brain in this condition can be established.

The mouse soluble GFRalpha4 receptor activates RET independently of its ligand persephin.

Glial cell line-derived neurotrophic factor (GDNF) family ligands (GFLs) all signal through the transmembrane receptor tyrosine kinase RET. The signalling complex consists of GFLs, GPI-anchored ligand binding GDNF family receptor alphas (GFRalphas) and RET. Signalling via RET is required for the development of the nervous system and the kidney, as well as for spermatogenesis. However, constitutive activation of RET is implicated as a cause in several diseases. Mutations of the RET proto-oncogene cause the inherited cancer syndrome multiple endocrine neoplasia type 2 (MEN 2). Recently, it has been suggested that mutations in the persephin binding GFRalpha4 receptor may have a potentially modifying role in MEN 2. Several naturally occurring, different splice variants of the mammalian GFRalpha4 have been reported. A 7 bp insertion-mutation in the human GFRalpha4 gene causes a shift of reading frame and thereby changes the balance between the transcripts encoding GPI-anchored and soluble GFRalpha4 receptors. We report here that the mammalian soluble GFRalpha4 can activate RET independently of its preferential ligand, persephin. Our data show that soluble GFRalpha4 can associate with, and induce, phosphorylation of RET. In addition, our data show that this isoform of GFRalpha4 can induce downstream signalling, as well as neuronal survival and differentiation, in the absence of persephin. These results suggest that, in line with the previous report, GFRalpha4 may be a candidate gene for, or modifier of, the MEN 2 diseases.

Metabolomic profiling by near-infrared spectroscopy as a tool to assess embryo viability: a novel, non-invasive method for embryo selection.

BACKGROUND: The morphology of an embryo has a limited predictive value for assessing viability and ongoing pregnancy, therefore new selection tools are needed to maintain success rates with single-embryo transfer (SET). In this study, we investigated if metabolomic profiling of biomarkers of embryo culture medium by near-infrared (NIR) spectroscopy has a correlation with ongoing pregnancy in SET. METHODS: A total of 333 patients scheduled for in vitro fertilization (IVF) with SET were included in the study. Embryos were selected for transfer by morphological criteria on Days 2 and 3 of in vitro culture, and left over culture media samples were analyzed by NIR spectroscopy. RESULTS: The NIR spectral analysis produced unique metabolomic profiles that correlated to an embryo's reproductive potential. Resulting relative viability scores between positive and negative pregnancy outcomes were statistically significant (P < 0.03). A logistic regression of factors correlated to pregnancy outcomes showed that maternal age, percent fragmentation and relative viability scores all demonstrated a relationship. The extent of the correlation was determined by accuracy computation, where the accuracy of assessing viable embryos on Day 3 by metabolomic profiling was 53.6% and the accuracy of the morphological selection was 38.5%. In addition, the positive predictive value of metabolomic profiling was 0.365 and the negative predictive value was 0.830. CONCLUSIONS: NIR metabolomic profiling of spent embryo culture media was able to distinguish viable embryos from non-viable embryos for reproduction.

Impact of arbuscular mycorrhizal fungi on uranium accumulation by plants.

Contamination by uranium (U) occurs principally at U mining and processing sites. Uranium can have tremendous environmental consequences, as it is highly toxic to a broad range of organisms and can be dispersed in both terrestrial and aquatic environments. Remediation strategies of U-contaminated soils have included physical and chemical procedures, which may be beneficial, but are costly and can lead to further environmental damage. Phytoremediation has been proposed as a promising alternative, which relies on the capacity of plants and their associated microorganisms to stabilize or extract contaminants from soils. In this paper, we review the role of a group of plant symbiotic fungi, i.e. arbuscular mycorrhizal fungi, which constitute an essential link between the soil and the roots. These fungi participate in U immobilization in soils and within plant roots and they can reduce root-to-shoot translocation of U. However, there is a need to evaluate these observations in terms of their importance for phytostabilization strategies.

Role and influence of mycorrhizal fungi on radiocesium accumulation by plants.

This review summarizes current knowledge on the contribution of mycorrhizal fungi to radiocesium immobilization and plant accumulation. These root symbionts develop extended hyphae in soils and readily contribute to the soil-to-plant transfer of some nutrients. Available data show that ecto-mycorrhizal (ECM) fungi can accumulate high concentration of radiocesium in their extraradical phase while radiocesium uptake and accumulation by arbuscular mycorrhizal (AM) fungi is limited. Yet, both ECM and AM fungi can transport radiocesium to their host plants, but this transport is low. In addition, mycorrhizal fungi could thus either store radiocesium in their intraradical phase or limit its root-to-shoot translocation. The review discusses the impact of soil characteristics, and fungal and plant transporters on radiocesium uptake and accumulation in plants, as well as the potential role of mycorrhizal fungi in phytoremediation strategies.

Effectiveness of a combined exercise training and home-based walking programme on physical activity compared with standard medical care in moderate COPD: a randomised controlled trial.

OBJECTIVE: To estimate the effectiveness of a 10-week combined exercise training and home-based walking programme on daily physical activity (PA) compared with standard medical care in patients with moderate chronic obstructive pulmonary disease (COPD). DESIGN: Randomised controlled trial. SETTING: Primary care physiotherapy. PARTICIPANTS: Consecutive patients with stable COPD at Gold Stage II with a score of two or more on the Medical Research Council Dyspnoea Scale. INTERVENTION: Ten-week combined exercise training and home-based walking programme compared with standard medical care. MAIN OUTCOMES: At baseline and after 10 weeks, daily PA was evaluated by accelerometry using three levels of intensity and expressed as metabolic equivalent of task. In addition, daily activities (Physical Activity Scale for the Elderly), functional exercise capacity (6-minute Walk Test), health-related quality of life (Chronic Respiratory Questionnaire) and exercise self-efficacy (Exercise Self-Regulatory Efficacy Scale) were measured. RESULTS: Fifty-two patients {34 females; mean age 70.2 [standard deviation (SD) 9.5] years; mean forced expiratory volume in 1second 67% (SD 9.2) of predicted} were randomised. PA, adjusted for baseline differences, increased significantly in the intervention group compared with the control group, by 26.1minutes/day [95% confidence interval (CI) 7.3 to 44.9]. The increase in functional capacity between groups was clinically relevant (34.0m, 95% CI 2.3 to 65.6) in favour of the intervention group. CONCLUSIONS: A combined exercise training and home-based walking programme in primary care physiotherapy improved PA in patients with moderate COPD. Clinical trial registration number NL24766.018.08.

Inhibition of ATM and ATR kinase activities by the radiosensitizing agent, caffeine.

Caffeine exposure sensitizes tumor cells to ionizing radiation and other genotoxic agents. The radiosensitizing effects of caffeine are associated with the disruption of multiple DNA damage-responsive cell cycle checkpoints. The similarity of these checkpoint defects to those seen in ataxia-telangiectasia (A-T) suggested that caffeine might inhibit one or more components in an A-T mutated (ATM)-dependent checkpoint pathway in DNA-damaged cells. We now show that caffeine inhibits the catalytic activity of both ATM and the related kinase, ATM and Rad3-related (ATR), at drug concentrations similar to those that induce radiosensitization. Moreover, like ATM-deficient cells, caffeine-treated A549 lung carcinoma cells irradiated in G2 fail to arrest progression into mitosis, and S-phase-irradiated cells exhibit radioresistant DNA synthesis. Similar concentrations of caffeine also inhibit gamma- and UV radiation-induced phosphorylation of p53 on Ser15, a modification that may be directly mediated by the ATM and ATR kinases. DNA-dependent protein kinase, another ATM-related protein involved in DNA damage repair, was resistant to the inhibitory effects of caffeine. Likewise, the catalytic activity of the G2 checkpoint kinase, hChk1, was only marginally suppressed by caffeine but was inhibited potently by the structurally distinct radiosensitizer, UCN-01. These data suggest that the radiosensitizing effects of caffeine are related to inhibition of the protein kinase activities of ATM and ATR and that both proteins are relevant targets for the development of novel anticancer agents.

Isolation of human pituitary prolactin.

A process developed earlier for the extraction of human follitropin, lutropin, thyrotropin and growth hormone from homogenized frozen pituitaries provided a residue utilized for the isolation of prolactin. The isolation procedure involved extraction at pH 9.8, molecular sieve chromatography on Sepharose CL-6B, hydrophobic interaction chromatography on phenyl-Sepharose CL-4B, molecular sieve chromatography on Sephadex G-100 Superfine, and ion-exchange chromatography on DEAE-Sepharose CL-6B using a convex gradient. The progressive purification was guided by radioimmunoassays. The final product was obtained in yields of 31 microgram/gland, and was equipotent with a pituitary preparation (VLS-3) supplied by the National Pituitary Agency (NIH, Bethesda, U.S.A.). Contamination hormones negligible (less than 0.05%). No heterogeneity of the isolated prolactin was observed by sedimentation-equilibrium analysis in the ultracentrifuge, by SDS electrophoresis in polyacrylamide gel or by molecular sieve chromatography in 6 M guanidine hydrochloride. These different techniques gave values in the range of 21 000-23 000 for the molecular weight of prolactin. In free zone electrophoresis, and also in polyacrylamide gel electrophoresis the prolactin preparation was, however, heterogeneous and resolved at alkaline pH into three distinct components. The former technique permitted isolation and assay of the components, indicating that they were all fully active.

Human pituitary thyrotropin. Isolation and recombination of subunit isoforms.

The alpha and beta subunits of human pituitary thyrotropin were prepared by a process developed earlier. Each subunit preparation contained four isoforms which were isolated by preparative agarose-suspension electrophoresis. The alpha subunit isoforms were homogeneous upon examination by analytical electrophoresis in polyacrylamide gel. Contrarily, the isolated beta subunit isoforms were always to some extent contaminated by the adjacent more acidic component. This was considered to show a transformation of these forms favoured by hydroxyl ions. Amino acid analysis revealed no differences between the alpha isoforms nor between the beta isoforms, and the amino acid compositions were in very good agreement with those earlier obtained for multi-alpha and multi-beta preparations. Attempts to recombine different alpha and beta isoforms were made at pH 7.0. The activities of recombined thyrotropin (in terms of MRC Research Standard A) ranged from 1.1 unit/mg (recombination of two minor components) to 3.5 units/mg (recombination of two major components). The activities of native and recombined thyrotropins as well as the subunit activities were followed by radioimmunoassays. The activity of native thyrotropin as a function of time was studied under different storage conditions. The subunit activities were also measured. All conditions resulted in a decrease in the thytrotropin activity (about 40% in 10 weeks). This decrease was not due to dissociation as the subunit activities remained approximately constant.

Human pituitary prolactin: isolation and characterization of three isohormones with different bioassay and radioimmunoassay activities.

Three forms of human pituitary prolactin, separable at alkaline pH in a highly purified preparation, were isolated by means of column electrophoresis in agarose suspension. The most acidic component showed a significantly lower radioimmunological activity but a higher bioactivity than the other two components, which were approximately equipotent in both assays. Consequently, in both assays the most acidic component differed markedly from the other components. Amino acid analysis indicated close similarity between the three components and no size heterogeneity was observed by sodium dodecyl sulphate electrophoresis in polyacrylamide gel. A high degree of purity of the isolated components was demonstrated by analytical electrophoresis in polyacrylamide gel at alkaline pH. Runs in the same medium also revealed that the difference in electrophoretic migration velocity remained after reduction and alkylation of the isohormones. A comparison of the migrations of the S-carboxymethylated and the S-carbamidomethylated derivatives with those of the unmodified components indicated that the diversity in electrophoretical behaviour of two adjacent isohormones was consistent with a difference in one single net charge. By analytical isoelectric focusing the component of intermediate migration velocity was resolved into two distinct bands proposed to contain isohormones differing only in the exchange of one residue of aspartic acid for one of glutamic acid. The isoelectric points of the prolactin isomers were all in the range of 5.7--5.9.

Isolation of five active thyrotropin components from human pituitary gland.

A procedure is described for the isolation of human pituitary thyroid-stimulating hormone (thyrotropin). The starting material was a side-fraction provided by the earlier developed process for the purification of growth hormone from whole frozen pituitaries. This fraction was further purified by successive chromatography on Bio-Gel P-150, Bio-Gel HT hydroxyapatite, and SP-Sephadex C-50. The resulting preparation was obtained in yields of 10 mg/kg of pituitary tissue and had a thyrotropin potency of 11 units human Research Standard A/mg as measured by a specific radioimmunoassay. Contamination by other pituitary hormone activities was low. In the ultracentrifuge a single sedimenting boundary was registered with an s20,w value of 2.7 S. The molecular weight as determined by sedimentation-equilibrium experiments was 34 000 in phosphate buffer, pH 7.0, and 17 700 in 1 M propionic acid. This thyrotropin preparation was, however, electrophoretically heterogenous. Following preparative polyacrylamide gel electrophoresis five different components associated with thyrotropin activity were isolated. Isolation on a preparative scale of electrophoretically homogeneous human thyrotropin has not earlier been reported. One of the thyrotropin components was characterized with respect to molecular weight and amino acid composition. The data were consistent with a molecular weight of 33 000 from sedimentation-equilibrium analysis at pH 7 and with 268 amino acid residues per molecule.

Human pituitary thyrotropin. Characterization of five glycoproteins with thyrotropin activity.

Human pituitary thyrotropin prepared by chromatography on hydroxyapatite or on SP-Sephadex was fractionated into five active components by preparative poly-acrylamide gel electrophoresis. The potency of the five components was 4-9 units human Research Standard A/mg. Examination of the components by analytical electrophoresis and by immunological methods revealed no heterogeneity. Ultracentrifugaiton of the three major components showed homogeneity with sedimentaiton coefficinets in the range of 2.4-3.0 S and a value for the molecular weight of about 33 000. Amino acid and carbohydrate analyses indicated close similarites between the five components.