Universality, limits and predictability of gold-medal performances at the Olympic Games

Inspired by the Games held in ancient Greece, modern Olympics represent the world's largest pageant of athletic skill and competitive spirit. Performances of athletes at the Olympic Games mirror, since 1896, human potentialities in sports, and thus provide an optimal source of information for studying the evolution of sport achievements and predicting the limits that athletes can reach. Unfortunately, the models introduced so far for the description of athlete performances at the Olympics are either sophisticated or unrealistic, and more importantly, do not provide a unified theory for sport performances. Here, we address this issue by showing that relative performance improvements of medal winners at the Olympics are normally distributed, implying that the evolution of performance values can be described in good approximation as an exponential approach to an a priori unknown limiting performance value. This law holds for all specialties in athletics-including running, jumping, and throwing-and swimming. We present a self-consistent method, based on normality hypothesis testing, able to predict limiting performance values in all specialties. We further quantify the most likely years in which athletes will breach challenging performance walls in running, jumping, throwing, and swimming events, as well as the probability that new world records will be established at the next edition of the Olympic Games.Comment: 8 pages, 3 figures, 1 table. Supporting information files and data are available at filrad.homelinux.or

Increased Postprandial Nonesterified Fatty Acid Appearance and Oxidation in Type 2 Diabetes Is Not Fully Established in Offspring of Diabetic Subjects

BACKGROUND: It has been proposed that abnormal postprandial plasma nonesterified fatty acid (NEFA) metabolism may participate in the development of tissue lipotoxicity and type 2 diabetes (T2D). We previously found that non-diabetic offspring of two parents with T2D display increased plasma NEFA appearance and oxidation rates during intravenous administration of a fat emulsion. However, it is currently unknown whether plasma NEFA appearance and oxidation are abnormal during the postprandial state in these subjects at high-risk of developing T2D. METHODOLOGY: Palmitate appearance and oxidation rates and glycerol appearance rate were determined in eleven healthy offspring of two parents with T2D (positive family history, FH+), 13 healthy subjects without first-degree relatives with T2D (FH-) and 12 subjects with T2D at fasting, during normoglycemic hyperinsulinemic clamp and during continuous oral intake of a standard liquid meal to achieve steady postprandial NEFA and triacylglycerols (TG) without and with insulin infusion to maintain similar glycemia in all three groups. PRINCIPAL FINDINGS: Plasma palmitate appearance and oxidation were higher at fasting and during the clamp conditions in the T2D group (all P<0.05). In the postprandial state, palmitate appearance, oxidative and non oxidative rates were all elevated in T2D (all P<0.05) but not in FH+. Both T2D and FH+ displayed elevated postprandial TG vs. FH- (P<0.001). Acute correction of hyperglycemia during the postprandial state did not affect these group differences. Increased waist circumference and BMI were positively associated with elevated postprandial plasma palmitate appearance and oxidation. CONCLUSIONS/SIGNIFICANCE: Postprandial plasma NEFA intolerance observed in subjects with T2D is not fully established in non-diabetic offspring of both parents with T2D, despite the presence of increased postprandial plasma TG in the later. Elevated postprandial plasma NEFA appearance and oxidation in T2D is observed despite acute correction of the exaggerated glycemic excursion in this group

Novel desmoplakin mutation: juvenile biventricular cardiomyopathy with left ventricular non-compaction and acantholytic palmoplantar keratoderma

Two sons of a consanguineous marriage developed biventricular cardiomyopathy. One boy died of severe heart failure at the age of 6 years, the other was transplanted because of severe heart failure at the age of 10 years. In addition, focal palmoplantar keratoderma and woolly hair were apparent in both boys. As similar phenotypes have been described in Naxos disease and Carvajal syndrome, respectively, the genes for plakoglobin (JUP) and desmoplakin (DSP) were screened for mutations using direct genomic sequencing. A novel homozygous 2 bp deletion was identified in an alternatively spliced region of DSP. The deletion 5208_5209delAG led to a frameshift downstream of amino acid 1,736 with a premature truncation of the predominant cardiac isoform DSP-1. This novel homozygous truncating mutation in the isoform-1 specific region of the DSP C-terminus caused Carvajal syndrome comprising severe early-onset heart failure with features of non-compaction cardiomyopathy, woolly hair and an acantholytic form of palmoplantar keratoderma in our patient. Congenital hair abnormality and manifestation of the cutaneous phenotype in toddler age can help to identify children at risk for cardiac death

Inhibition of lipolysis in Type 2 diabetes normalizes glucose disposal without change in muscle glycogen synthesis rates

Suppression of lipolysis by acipimox is known to improve insulin-stimulated glucose disposal, and this is an important phenomenon. The mechanism has been assumed to be an enhancement of glucose storage as glycogen, but no direct measurement has tested this concept or its possible relationship to the reported impairment in insulin-stimulated muscle ATP production. Isoglycaemic–hyperinsulinaemic clamps with [13C]glucose infusion were performed on Type 2 diabetic subjects and matched controls with measurement of glycogen synthesis by 13C MRS (magnetic resonance spectroscopy) of muscle. 31P saturation transfer MRS was used to quantify muscle ATP turnover rates. Glucose disposal rates were restored to near normal in diabetic subjects after acipimox (6.2±0.8 compared with 4.8±0.6 mg·kgffm−1·min−1; P<0.01; control 6.6±0.5 mg·kgffm−1·min−1; where ffm, is fat-free mass). The increment in muscle glycogen concentration was 2-fold higher in controls compared with the diabetic group, and acipimox administration to the diabetic group did not increase this (2.0±0.8 compared with 1.9±1.1 mmol/l; P<0.05; control, 4.0±0.8 mmol/l). ATP turnover rates did not increase during insulin stimulation in any group, but a modest decrease in the diabetes group was prevented by lowering plasma NEFAs (non-esterified fatty acids; 8.4±0.7 compared with 7.1±0.5 μmol·g−1·min−1; P<0.05; controls 8.6±0.8 μmol·g−1·min−1). Suppression of lipolysis increases whole-body glucose uptake with no increase in the rate of glucose storage as glycogen but with increase in whole-body glucose oxidation rate. ATP turnover rate in muscle exhibits no relationship to the acute metabolic effect of insulin

Adipose triglyceride lipase (ATGL) expression in human skeletal muscle is type I (oxidative) fiber specific

Accumulation of triacylglycerol (TAG) and lipid intermediates in skeletal muscle plays an important role in the etiology of insulin resistance and type 2 diabetes mellitus. Disturbances in skeletal muscle lipid turnover and lipolysis may contribute significantly to this. So far, knowledge on the regulation of muscle lipolysis is limited. Recently the identification of a new lipase was reported: adipose triglyceride lipase (ATGL). ATGL deficient animals show significant lipid accumulation in skeletal muscle, which may indicate that ATGL plays a pivotal role in skeletal muscle lipolysis. However, until now, it is still unknown whether ATGL protein is expressed in human skeletal muscle. Therefore, the aim of the present study was to investigate whether ATGL is expressed at the protein level in human skeletal muscle, and to examine whether its expression is fiber-type specific. To accomplish this, we established an imunohistochemical and immunofluorescent staining procedure to study ATGL protein expression in relation to fiber type in human vastus lateralis muscle of eight male subjects (BMI range: 21.0–34.5 kg/m2 and age: 38–59 years). In the present paper we report for the first time that ATGL protein is indeed expressed in human skeletal muscle. Moreover, ATGL is exclusively expressed in type I (oxidative) muscle fibers, suggesting a pivotal role for ATGL in intramuscular fatty acid handling, lipid storage and breakdown

Antiseptics and disinfectants for the treatment of bacterial vaginosis: a systematic review

Background: The study objective was to assess the available data on efficacy and tolerability of antiseptics and disinfectants in treating bacterial vaginosis (BV). Methods: A systematic search was conducted by consulting PubMed (1966-2010), CINAHL (1982-2010), IPA (1970-2010), and the Cochrane CENTRAL databases. Clinical trials were searched for by the generic names of all antiseptics and disinfectants listed in the Anatomical Therapeutic Chemical (ATC) Classification System under the code D08A. Clinical trials were considered eligible if the efficacy of antiseptics and disinfectants in the treatment of BV was assessed in comparison to placebo or standard antibiotic treatment with metronidazole or clindamycin and if diagnosis of BV relied on standard criteria such as Amsel\u27s and Nugent\u27s criteria. Results: A total of 262 articles were found, of which 15 reports on clinical trials were assessed. Of these, four randomised controlled trials (RCTs) were withheld from analysis. Reasons for exclusion were primarily the lack of standard criteria to diagnose BV or to assess cure, and control treatment not involving placebo or standard antibiotic treatment. Risk of bias for the included studies was assessed with the Cochrane Collaboration\u27s tool for assessing risk of bias. Three studies showed non-inferiority of chlorhexidine and polyhexamethylene biguanide compared to metronidazole or clindamycin. One RCT found that a single vaginal douche with hydrogen peroxide was slightly, though significantly less effective than a single oral dose of metronidazole. Conclusion: The use of antiseptics and disinfectants for the treatment of BV has been poorly studied and most studies are somehow methodologically flawed. There is insufficient evidence at present to advocate the use of these agents, although some studies suggest that some antiseptics may have equal efficacy compared to clindamycin or metronidazole. Further study is warranted with special regard to the long-term efficacy and safety of antiseptics and disinfectants for vaginal use

Reference range of liver corrected T1 values in a population at low risk for fatty liver disease-a UK Biobank sub-study, with an appendix of interesting cases

Purpose: Corrected T1 (cT1) value is a novel MRI-based quantitative metric for assessing a composite of liver inflammation and fibrosis. It has been shown to distinguish between non-alcoholic fatty liver disease (NAFL) and non-alcoholic steatohepatitis. However, these studies were conducted in patients at high risk for liver disease. This study establishes the normal reference range of cT1 values for a large UK population, and assesses interactions of age and gender. Methods: MR data were acquired on a 1.5T system as part of the UK Biobank Imaging Enhancement study. Measures for Proton Density Fat Fraction and cT1 were calculated from the MRI data using a multi-parametric MRI software application. Data that did not meet quality criteria were excluded from further analysis. Inter and intra-reader variability was estimated in a set of data. A cohort at low risk for NAFL was identified by excluding individuals with BMI ≥ 25kg/m2 and PDFF ≥ 5%. Of the 2816 participants with data of suitable quality, 1037 (37%) were classified as at low risk. Results: The cT1 values in the low risk population ranged from 573 to 852 ms with a median of 666 ms and interquartile range from 643-694 ms. Iron correction of T1 was necessary in 36.5% of this reference population. Age and gender had minimal effect on cT1 values. Conclusion: The majority of cT1 values are tightly clustered in a population at low risk for NAFL; suggesting it has the potential to serve as a new quantitative imaging biomarker for studies of liver health and disease

Rapid in situ imaging and whole genome sequencing of biofilm in neonatal feeding tubes: a clinical proof of concept

The bacterial flora of nasogastric feeding tubes and faecal samples were analysed for a low-birth weight (725g) neonate EGA 25 weeks in intensive care. Samples were collected at age 6 and 8 weeks of life. Optical coherence tomography (OCT) was used to visualise bacterial biofilms inside the nasogastric feeding tubes. The biofilm was heterogeneously distributed along the tube lumen wall, and had a depth of up to 500µm. The bacterial biofilm and faecal samples included Enterococcus faecalis and Enterobacter hormaechei. Representative strains, recovered from both feeding tubes and faecal samples, were whole genome sequenced using Illumina, Mi-Seq, which revealed indistinguishable strains, each with less than 28 SNP differences, of E. faecalis and E. hormaechei. The E. faecalis strains were from two sequence types (ST191 and ST211) and encoded for a number of traits related to biofilm formation (BopD), adherence (Epb pili), virulence (cps loci, gelatinase, SprE) and antibiotic resistances (IsaA, tetM). The E. hormaechei were all ST106, and encoded for blaACT-15 β–lactamase and fosfomycin resistance (fosA). This proof of concept study demonstrates that bacterial flora within the neonatal feeding tubes may influence the bacterial colonisation of the intestinal tract and can be visualised nondestructively using OCT

Chronic non-specific low back pain - sub-groups or a single mechanism?

Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions for chronic non-specific low back pain indicate limited effectiveness for most commonly applied interventions and approaches. Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of effectiveness is at odds with their clinical experience of managing patients with back pain. A common explanation for this discrepancy is the perceived heterogeneity of patients with chronic non-specific low back pain. It is felt that the effects of treatment may be diluted by the application of a single intervention to a complex, heterogeneous group with diverse treatment needs. This argument presupposes that current treatment is effective when applied to the correct patient. An alternative perspective is that the clinical trials are correct and current treatments have limited efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important that the sub-grouping paradigm is closely examined. This paper argues that there are numerous problems with the sub-grouping approach and that it may not be an important reason for the disappointing results of clinical trials. We propose instead that current treatment may be ineffective because it has been misdirected. Recent evidence that demonstrates changes within the brain in chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of cortical reorganisation and degeneration. This perspective offers interesting insights into the chronic low back pain experience and suggests alternative models of intervention. Summary: The disappointing results of clinical research are commonly explained by the failure of researchers to adequately attend to sub-grouping of the chronic non-specific low back pain population. Alternatively, current approaches may be ineffective and clinicians and researchers may need to radically rethink the nature of the problem and how it should best be managed