Fluid use in mountain bikers - self-reported practices

Background and objectives. Little is known of the fluid replacement habits of participants in mountain bike (MTB) endurance events. This survey set out to determine the current perceptions and practices of this group of endurance athletes. Method. Four hundred and twelve participants in the 3- day 2006 Sani2C (MTB) race completed questionnaires that elicited information regarding their regular fluid intake practices during competitive MTB endurance events. This included their general approach to fluid replacement, their fluid intake practices (type, amount and frequency), urine output and hydration status. Results. While 70% (N = 290) reported that they based their fluid intake practices on personal past experiences, less than half the group (N = 177, 43%) were aware of official sport-specific guidelines. Although 86% (N = 354) reported making use of commercially available sport-specific drinks, consumption of water alone was reported by 34% of respondents (N = 140). The majority (N = 225, 55%) of the mountain bikers reported drinking every 16 - 30 minutes during an endurance ride, while 35% (N = 144) reported drinking every 0 - 15 minutes. Fifty-three per cent (N = 182) of the male respondents and 45% (N = 23) of female respondents reported a routine intake of ≥ 750 ml per hour during endurance rides. This included 2 women who reported regular intakes of between 1 500 and 2 000 ml/hr. Only 7 (2%) reported receiving medical care for dehydration following their participation in previous MTB rides. Conclusions. This survey indicates that although more than half of the mountain bikers did not acknowledge specific awareness of the official fluid replacement guidelines, over 80% reported drinking regularly during a race, and 52% (N = 212) reported a usual intake of ≥ 750 ml/hr during endurance races. Until scientific studies have carefully examined the hydration status and fluid replacement needs of mountain bikers, MTB cyclists are cautioned against the practice of over-hydrating. South African Journal of Sports Medicine Vol. 19 (2) 2007: pp. 52-5

Tachycardia-induced Cardiomyopathy (Tachycardiomyopathy)

The term tachycardia-induced cardio-myopathy or tachycardiomyopathy refers to impairment in left ventricular function secondary to chronic tachycardia, which is partially or completely reversible once the tachyarrhythmia is controlled. Tachycardia-induced cardiomyopathy has been shown to occur both in experimental models and in patients with incessant tachyarrhythmia. Data from several studies and from case reports have shown that rate control by means of cardioversion, negative chronotropic agents, and surgical or catheter-based atrio-ventricular node ablation, resulted in significant improvement of systolic function. The diagnosis of tachycardia-induced cardiomyopathy is usually made following observation of marked improvement in systolic function after normalization of heart rate. Clinicians should be aware that patients with unexplained systolic dysfunction may have tachycardia-induced cardiomyo-pathy, and that controlling the arrhythmia may result in improvement of systolic function

New mutations at the imprinted Gnas cluster show gene dosage effects of Gsα in postnatal growth and implicate XLαs in bone and fat metabolism, but not in suckling

The imprinted Gnas cluster is involved in obesity, energy metabolism, feeding behavior, and viability. Relative contribution of paternally expressed proteins XLαs, XLN1, and ALEX or a double dose of maternally expressed Gsα to phenotype has not been established. In this study, we have generated two new mutants (Ex1A-T-CON and Ex1A-T) at the Gnas cluster. Paternal inheritance of Ex1A-T-CON leads to loss of imprinting of Gsα, resulting in preweaning growth retardation followed by catch-up growth. Paternal inheritance of Ex1A-T leads to loss of imprinting of Gsα and loss of expression of XLαs and XLN1. These mice have severe preweaning growth retardation and incomplete catch-up growth. They are fully viable probably because suckling is unimpaired, unlike mutants in which the expression of all the known paternally expressed Gnasxl proteins (XLαs, XLN1 and ALEX) is compromised. We suggest that loss of ALEX is most likely responsible for the suckling defects previously observed. In adults, paternal inheritance of Ex1A-T results in an increased metabolic rate and reductions in fat mass, leptin, and bone mineral density attributable to loss of XLαs. This is, to our knowledge, the first report describing a role for XLαs in bone metabolism. We propose that XLαs is involved in the regulation of bone and adipocyte metabolism

Translational outcomes in a full gene deletion of ubiquitin protein ligase E3A rat model of Angelman syndrome.

Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by developmental delay, impaired communication, motor deficits and ataxia, intellectual disabilities, microcephaly, and seizures. The genetic cause of AS is the loss of expression of UBE3A (ubiquitin protein ligase E6-AP) in the brain, typically due to a deletion of the maternal 15q11-q13 region. Previous studies have been performed using a mouse model with a deletion of a single exon of Ube3a. Since three splice variants of Ube3a exist, this has led to a lack of consistent reports and the theory that perhaps not all mouse studies were assessing the effects of an absence of all functional UBE3A. Herein, we report the generation and functional characterization of a novel model of Angelman syndrome by deleting the entire Ube3a gene in the rat. We validated that this resulted in the first comprehensive gene deletion rodent model. Ultrasonic vocalizations from newborn Ube3am-/p+ were reduced in the maternal inherited deletion group with no observable change in the Ube3am+/p- paternal transmission cohort. We also discovered Ube3am-/p+ exhibited delayed reflex development, motor deficits in rearing and fine motor skills, aberrant social communication, and impaired touchscreen learning and memory in young adults. These behavioral deficits were large in effect size and easily apparent in the larger rodent species. Low social communication was detected using a playback task that is unique to rats. Structural imaging illustrated decreased brain volume in Ube3am-/p+ and a variety of intriguing neuroanatomical phenotypes while Ube3am+/p- did not exhibit altered neuroanatomy. Our report identifies, for the first time, unique AS relevant functional phenotypes and anatomical markers as preclinical outcomes to test various strategies for gene and molecular therapies in AS

Various heat-treated nickel–titanium rotary instruments evaluated in S-shaped simulated resin canals

AbstractBackground/purposeHeat treatment of nickel–titanium (NiTi) alloy produces a better arrangement of the crystal structure, thereby leading to increased flexibility and improved fatigue resistance or plastic behavior. This study aimed to assess the performance of various heat-treated NiTi rotary instruments in S-shaped resin canals.Materials and methodsForty S-shaped resin canals were instrumented (10/group) with either Twisted Files (R-phase), WaveOne (M-wire), Hyflex CM, or V Taper 2H (CM-wire) with the same apical size and taper (25/0.08). Each S-shaped resin canal was scanned both before and after instrumentation with microcomputed tomography. Changes in canal volume and transportation were evaluated at regular intervals (0.5 mm). Differences between instruments at the apical curve, coronal curve, and straight portion of the canals were analyzed statistically.ResultsAll tested instruments caused more transportation at the coronal rather than apical curvatures, with the exception of Twisted Files for which apical transportation was the highest for any instrument or location (P<0.05). The transportation was mostly influenced by the alloy type rather than their cross-sectional characteristics (P<0.05). The volumetric increase after instrumentation was similar for all tested instruments at the apical curve (P>0.05), whereas Hyflex CM created the most conservative preparations at the coronal curve (P<0.05). At the straight portion, volumetric changes were largest for Twisted Files and smallest for V Taper 2H (P<0.05).ConclusionAmongst heat-treated NiTi instruments, the CM-wire based instruments created the most favorable preparations in S-shaped resin canals

Light smoking at base-line predicts a higher mortality risk to women than to men; evidence from a cohort with long follow-up

BACKGROUND: There is conflicting evidence as to whether smoking is more harmful to women than to men. The UK Cotton Workers’ Cohort was recruited in the 1960s and contained a high proportion of men and women smokers who were well matched in terms of age, job and length of time in job. The cohort has been followed up for 42 years. METHODS: Mortality in the cohort was analysed using an individual relative survival method and Cox regression. Whether smoking, ascertained at baseline in the 1960s, was more hazardous to women than to men was examined by estimating the relative risk ratio women to men, smokers to never smoked, for light (1–14), medium (15–24), heavy (25+ cigarettes per day) and former smoking. RESULTS: For all-cause mortality relative risk ratios were 1.35 for light smoking at baseline (95% CI 1.07-1.70), 1.15 for medium smoking (95% CI 0.89-1.49) and 1.00 for heavy smoking (95% CI 0.63-1.61). Relative risk ratios for light smoking at baseline for circulatory system disease was 1.42 (95% CI 1.01 to 1.98) and for respiratory disease was 1.89 (95% CI 0.99 to 3.63). Heights of participants provided no explanation for the gender difference. CONCLUSIONS: Light smoking at baseline was shown to be significantly more hazardous to women than to men but the effect decreased as consumption increased indicating a dose response relationship. Heavy smoking was equally hazardous to both genders. This result may help explain the conflicting evidence seen elsewhere. However gender differences in smoking cessation may provide an alternative explanation

Management of Cushing syndrome in children and adolescents: experience of a single tertiary centre

The diagnosis and management of paediatric Cushing syndrome (CS) is highly challenging. This study aims to characterise its presentation, diagnosis, management and outcome by a retrospective case review of 30 patients (14 females) followed at a single tertiary paediatric endocrinology centre over a 30-year period. At presentation, median age was 8.9 years (0.2-15.5) and the commonest manifestations were weight gain (23/30), hirsutism (17/30), acne (15/30) and hypertension (15/30). Growth retardation was present in 11/30. Median body mass index (BMI) was +2.1 standard deviation score (SDS) (-6.5 to +4.6). Urinary free cortisol (UFC) was abnormal in 17/18 (94 %), midnight cortisol in 27/27 (100 %) and low-dose dexamethasone suppression (LDDS) test in 20/20 (100 %). High-dose dexamethasone suppression (HDDS) test was abnormal in 6/6 (100 %) of adrenal tumours, 1/10 (10 %) of Cushing disease (CD) and 1/2 (50 %) of ectopic tumours. Bilateral inferior petrosal sinus sampling (IPSS) identified five CD cases and one ectopic tumour. All patients underwent surgery and subsequently required cortisol replacement. Final diagnoses were 16 CD, 11 adrenal disease, 2 ectopic ACTH-secreting lesions and 1 case of unidentified aetiology. One year post-diagnosis, median BMI was 0.5 SDS (-2.5 to +3.7), hypertension was present in 4/14 (28 %), and 43 % (12/30) of individuals were off hydrocortisone. CONCLUSION: The prevalence of the clinical manifestations differs from that reported in other series. Screening tests were highly sensitive, with UFC, midnight cortisol and LDDS performing well. One year post-treatment, BMI and BP normalised in the majority of patients and almost half of them were able to discontinue replacement hydrocortisone. WHAT IS KNOWN: •Cushing syndrome is an extremely rare entity in the paediatric and adolescent age groups, so not many cohort studies have been published in this population. •Several tests can be employed to firstly diagnose hypercortisolaemia and secondly identify the source of origin of it. The efficacy and safety of these tests in children is still uncertain. What is New: •This study includes cases due to the different aetiologies of endogenous hypercortisolaemia (pituitary, adrenal and ectopic hypercortisolaemia) allowing us to compare the differences in presentation, diagnosis, management and long-term outcome between the groups. •There is a difference in the prevalence of Cushing syndrome symptoms and in the performance of the tests in our cohort compared to previously published studies in the literature

Development of a Multiplex Real-Time PCR Assay for the detection of ruminant DNA

The U.S. Food and Drug Administration (FDA) has previously validated a real-time PCR-based assay that is currently being used by the FDA and several state laboratories as the official screening method. Due to several shortcomings to the assay, a multiplex real-time PCR assay (MRTA) to detect three ruminant species (bovine, caprine, and ovine) was developed using a lyophilized bead design. The assay contained two primer or probe sets: a "ruminant" set to detect bovine-, caprine-, and ovine-derived materials and a second set to serve as an internal PCR control, formatted using a lyophilized bead design. Performance of the assay was evaluated against stringent acceptance criteria developed by the FDA's Center for Veterinary Medicine's Office of Research. The MRTA for the detection of ruminant DNA passed the stringent acceptance criteria for specificity, sensitivity, and selectivity. The assay met sensitivity and reproducibility requirements by detecting 30 of 30 complete feed samples fortified with meals at 0.1 % (wt/wt) rendered material from each of the three ruminant species. The MRTA demonstrated 100 % selectivity (0.0 % false positives) for negative controls throughout the assessment period. The assay showed ruggedness in both sample selection and reagent preparation. Second and third analyst trials confirmed the quality of the written standard operating procedure with consistency of results. An external laboratory participating in a peer-verification trial demonstrated 100 % specificity in identifying bovine meat and bone meal, while exhibiting a 0.03 % rate of false positives. The assay demonstrated equal levels of sensitivity and reproducibility compared with the FDA's current validated real-time PCR assay. The assay detected three prohibited species in less than 1.5 h of total assay time, a significant improvement over the current real-time assay. These results demonstrated this assay's suitability for routine regulatory use both as a primary screening tool and as a confirmatory test

Assessment of protein allergenicity on the basis of immune reactivity: animal models.

Because of the public concern surrounding the issue of the safety of genetically modified organisms, it is critical to have appropriate methodologies to aid investigators in identifying potential hazards associated with consumption of foods produced with these materials. A recent panel of experts convened by the Food and Agriculture Organization and World Health Organization suggested there is scientific evidence that using data from animal studies will contribute important information regarding the allergenicity of foods derived from biotechnology. This view has given further impetus to the development of suitable animal models for allergenicity assessment. This article is a review of what has been achieved and what still has to be accomplished regarding several different animal models. Progress made in the design and evaluation of models in the rat, the mouse, the dog and in swine is reviewed and discussed