Cyclic movement frequency is associated with muscle typology in athletes

There is a continuing research interest in the muscle fiber type composition (MFTC) of athletes. Recently, muscle carnosine quantification by proton magnetic resonance spectroscopy (¹H-MRS) was developed as a new non-invasive method to estimate MFTC. This cross-sectional study aims to better understand estimated MFTC in relation to (a) different disciplines within one sport; (b) cyclic sport exercise characteristics; (c) within-athlete variability; and (d) athlete level. A total of 111 elite athletes (74 runners, 7 triathletes, 11 swimmers, 14 cyclists and 5 kayakers) and 188 controls were recruited to measure muscle carnosine in gastrocnemius and deltoid muscle by ¹H-MRS. Within sport disciplines, athletes were divided into subgroups (sprint-, intermediate-, and endurance-type). The controls were used as reference population to allow expression of the athletes’ data as Z-scores. Within different sports, endurance-type athletes systematically showed the lowest Z-score compared to sprint-type athletes, with intermediate-type athletes always situated in between. Across the different sports disciplines, carnosine content showed the strongest significant correlation with cyclic movement frequency (R = 0.86, P = 0.001). Both within and between different cyclic sports, estimated MFTC was divergent between sprint- and endurance-type athletes. Cyclic movement frequency, rather than exercise duration came out as the most determining factor for the optimal estimated MFTC in elite athletes.     

Mechanics of overground accelerated running vs. running on an accelerated treadmill

Unsteady state gait involving net accelerations has been studied overground and on a treadmill. Yet it has never been tested if and to what extent both set-ups are mechanically equal.This study documents the differences in ground reaction forces for accelerated running on an instrumented runway and running on an accelerating treadmill by building a theoretical framework which is experimentally put to the test.It is demonstrated that, in contrast to overground, no mean fore-after force impulse should be generated to follow an accelerating treadmill due to the absence of linear whole body acceleration. Accordingly, the adaptations in the braking phase (less braking) and propulsive phase (more propulsion) to accelerate overground are not present to follow an accelerating treadmill.It can be concluded that running on an accelerating treadmill is mechanically different from accelerated running overground.     

Synthesis and cytostatic evaluation of some 2-(5-substituted-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide

Various substituted 2-(5-substituted-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide 4a–g and 2-(5-substituted-1-(4-substituted benzyl)-2-oxoindolin-3-ylidene)-N-substituted hydrazine carbothioamide 5a–k were synthesized. The compounds were evaluated for their cytostatic activity against human Molt4/C8 and CEM T-lymphocytes as well as murine L1210 leukemia cells. Several of these compounds were endowed with low micromolar 50%-inhibitory concentration (IC₅₀) values, and some were virtually equally potent as melphalan. The most potent inhibitors against the murine leukemia cells were also most inhibitory against human T-lymphocyte tumor cells. 2-(5-fluoro-1-(4-fluorobenzyl)-2-oxoindolin-3-ylidene)-N-p-tolylhydrazine carbothioamide (5b) emerged as the most potent cytostatic compound among the tested compounds. The encouraging cytostatic data provide an adequate rationale for further modification of these molecular scaffolds.     

How Temperament and Personality Contribute to the Maladjustment of Children With Autism

To test the spectrum hypothesis—postulating that clinical and non-clinical samples are primarily differentiated by mean-level differences—, this study evaluates differences in parent-rated temperament, personality and maladjustment among a low-symptom (N = 81), a high-symptom (N = 94) ASD-group, and a comparison group (N = 500). These classic spectrum hypothesis tests are extended by adding tests for similarity in variances, reliabilities and patterns of covariation between relevant variables. Children with ASD exhibit more extreme means, except for dominance. The low- and high-symptom ASD-groups are primarily differentiated by mean sociability and internal distress. Striking similarities in reliability and pattern of covariation of variables suggest that comparable processes link traits to maladaptation in low- and high-symptom children with ASD and in children with and without autism.     

Fear-conditioned cues of impending pain facilitate attentional engagement.

AIMS OF STUDY: Selective attention to signals of impending pain allows the avoidance of bodily harm. In order to identify the attentional components involved in the selection of pain signals over competing demands, we used an emotional modification of an exogenous cueing task. METHODS: Fifty-two pain-free volunteers detected visual targets of which the location was correctly or incorrectly predicted by a spatial cue. Cues were emotionally modulated using differential classical conditioning. The conditioned cue (CS+) was sometimes followed by an electrocutaneous stimulus (UCS), thus becoming a pain signal, whereas the UCS never followed the other cue (CS-), referred to as safety signal. RESULTS: Analyses of response times showed that pain signals facilitated the directing of attention to their location in comparison to safety signals. In contrast, pain signals did not impair disengagement of attention from their location in comparison to safety signals. CONCLUSION: It is concluded that attention is more strongly engaged to a signal of impending pain compared with a cue signalling its absence. We explore why disengagement from the pain signal is not impaired compared to the safety signal. The findings are discussed in terms of the defensive importance of pain anticipation.     

Characteristics of serology-based vaccine potency models for foot-and-mouth disease virus

Background

Foot-and-mouth disease (FMD) vaccine potency testing involves hundreds of animals each year. Despite considerable efforts during the past decades, a challenge-free alternative vaccine potency test to replace the European protective dose 50% test (PD₅₀) has not been implemented yet. The aim of the present study was to further characterize the properties of serological vaccine potency models.

Methods

Logistic regression models were built for 5 serological assays from 3 different laboratories. The serum samples originated from 5 repeated PD₅₀ vaccine potency trials with a highly potent A/IRN/11/96 vaccine. Receiver Operating Characteristic analysis was used to determine a serological pass mark for predicting in vivo protected animals. Subsequently, an estimated PD₅₀ was calculated and the serotype dependency of the logistic models was investigated.

Results

Although differences were observed between the laboratories and the serological assays used, the logistic models accurately predicted the in vivo protection status of the animals in 74–93% of the cases and the antibody pass levels corresponded to 84–97% of protection, depending on the serological assay used. For logistic models that combine different serotypes, the model fit can be increased by inclusion of a serotype factor in the logistic regression function.

Conclusions

The in vitro estimated PD₅₀ method may be at least as precise as the in vivo PD₅₀ test and may accurately predict the PD₅₀ content of a vaccine. However, the laboratory-effect and the serotype-dependency should be further investigated.     

Validation of the FFM PD count technique for screening personality pathology in later middle-aged and older adults

Research on the applicability of the five factor model (FFM) to capture personality pathology coincided with the development of a FFM personality disorder (PD) count technique, which has been validated in adolescent, young, and middle-aged samples. This study extends the literature by validating this technique in an older sample. Five alternative FFM PD counts based upon the Revised NEO Personality Inventory (NEO PI-R) are computed and evaluated in terms of both convergent and divergent validity with the Assessment of DSM-IV Personality Disorders Questionnaire (shortly ADP-IV; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders – Fourth edition). For the best working count for each PD normative data are presented, from which cut-off scores are derived. The validity of these cut-offs and their usefulness as a screening tool is tested against both a categorical (i.e., the DSM-IV – Text Revision), and a dimensional (i.e., the Dimensional Assessment of Personality Pathology; DAPP) measure of personality pathology. All but the Antisocial and Obsessive-Compulsive counts exhibited adequate convergent and divergent validity, supporting the use of this method in older adults. Using the ADP-IV and the DAPP – Short Form as validation criteria, results corroborate the use of the FFM PD count technique to screen for PDs in older adults, in particular for the Paranoid, Borderline, Histrionic, Avoidant, and Dependent PDs. Given the age-neutrality of the NEO PI-R and the considerable lack of valid personality assessment tools, current findings appear to be promising for the assessment of pathology in older adults.     

Two 14-epi analogues of 1,25-dihydroxyvitamin D<Subscript>3</Subscript> protect human keratinocytes against the effects of UVB

In search of photoprotective agents, we recently demonstrated a protective effect of 1,25-dihydroxyvitamin D₃ [1,25(OH)₂D₃] against different events mediated by ultraviolet B (UVB) in human keratinocytes. Pharmacological doses of 1,25(OH)₂D₃ were required to obtain significant UVB protection; however, these doses cannot be used in vivo due to the calcemic properties of 1,25(OH)₂D₃. Therefore, we evaluated the photoprotective capacities of two low-calcemic 14-epi analogues of 1,25(OH)₂D₃, 19-nor-14-epi-23-yne-1,25(OH)₂D₃ (TX 522) and 19-nor-14,20-bisepi-23-yne-1,25(OH)₂D₃ (TX 527). Using cultured human keratinocytes, we investigated the influence of TX 522 and TX 527 on two hallmark events in UVB-irradiated keratinocytes: the induction of apoptosis and the production of interleukin-6 (IL-6). Treatment of the keratinocytes with TX 522 or TX 527, 24 h before irradiation, resulted in a significant and dose-dependent reduction of both UVB-induced apoptosis and IL-6 production. Both analogues were equally efficient in their anti-UVB effects and at least 100 times more potent than 1,25(OH)₂D₃. We further demonstrated that metallothionein (MT) mRNA expression was clearly induced by 1,25(OH)₂D₃ and both analogues. MT acts as a radical scavenger in oxygen-mediated UVB injury and its induction may therefore be relevant for the anti-UVB effects of 1,25(OH)₂D₃ and both analogues. Taken together, these findings create new perspectives for the use of active vitamin D analogues as photoprotective agents.     

Role of parvovirus B19 infection in childhood idiopathic thrombocytopenic purpura

Although parvovirus B19 exhibits a strong tissue-tropism for erythroid progenitor cells leading to anaemia, several case reports indicate that parvovirus B19 infection may also cause the development of thrombocytopenia. Despite recent studies, the frequency and clinical relevance of this association have remained questionable. Consequently, and in view of the paucity of evidence regarding a viral aetiology for idiopathic thrombocytopenic purpura (ITP), we examined the role of parvovirus B19 in 47 children with newly diagnosed ITP. Specific viral DNA indicating a current or recent parvovirus B19 infection was demonstrated in 6 of 47 patients (13%) employing the polymerase chain reaction technique. Our study suggests that children with ITP and associated parvovirus B19 infection are characterized by acute onset of profound thrombocytopenia. Among the parvovirus B19 positive children, duration of disease was brief in three children treated with immunoglobulin but chronic in the remaining three patients given high-dose steroids. Prospective studies are needed to confirm these initial observations. This virus should be considered as a possible aetiologic agent in some children with ITP.