Differences In Intrinsic Factors Research Articles

Can musculoskeletal screening test findings guide interventions for injury prevention and return from injury in field hockey?

ObjectivesThe aim of this study is to identify if intrinsic factors tested in the preseason screening (PSS) can identify an elevated risk of injury. This aim has two aspects; to assess whether previous injury is associated with ongoing deficits in performance, and to assess if the PSS can identify differences in intrinsic factors that profile risk of future injury. DesignA cohort of state level field hockey players were tested on a screening test battery including proprioception, postural stability, muscular strength and range of motion, to establish if these intrinsic factors were useful in identifying elevated risk of injury. Retrospective injury data was collated to determine association with previous injury and prospective injury data was collated to determine association with future injury. ParticipantsA total of 130 field hockey players were included in this study, from state level squads (age ± SD = 20.96 (3.75); height = 176.09 cm). Groups for prescreening and post screening injury status (injured/not injured) were established for comparison to screening test results. ResultsRight Active Movement Extent Discrimination Assessment (AMEDA), left AMEDA and right Y-balance test (YBT) anterior direction (Ant) were significantly associated (p < 0.05) with injury prior to screening. Right YBTAnt and right and left hip internal rotation (IR) were significantly associated (p < 0.05) with injury post screening. The YBTAnt and YBT posteromedial (PMed) reach directions and Hip IR are associated with previous hamstring injury and show a difference between post screening injured and non-injured groups. ConclusionsAMEDA, R YBTAnt, Hip IR tests should be a focus for recovery after previous injury and during season preparation. Full recovery may improve readiness to return to play and reduce risk of primary injury or re-injury. YBTAnt and YBTPmed and Hip IR show a performance deficit link between previous injury and subsequent re-injury of hamstrings. Since these are the most common re-injury types in this cohort, these tests are clinically useful in informing return to play decisions for hockey players.

Host-specific factors affect the pathogenesis of adverse reaction to metal debris

BackgroundAdverse Reaction to Metal Debris (ARMD) is a major reason for revision surgeries in patients with metal-on-metal (MoM) hip replacements. Most failures are related to excessively wearing implant producing harmful metal debris (extrinsic factor). As ARMD may also occur in patients with low-wearing implants, it has been suggested that there are differences in host-specific intrinsic factors contributing to the development of ARMD. However, there are no studies that have directly assessed whether the development of ARMD is actually affected by these intrinsic factors.MethodsWe included all 29 patients (out of 33 patients) with sufficient data who had undergone bilateral revision of ASR MoM hips (58 hips) at our institution. Samples of the inflamed synovia and/or pseudotumour were obtained perioperatively and sent to histopathological analysis. Total wear volumes of the implants were assessed. Patients underwent MARS-MRI imaging of the hips preoperatively. Histological findings, imaging findings and total wear volumes between the hips of each patient were compared.ResultsThe difference in wear volume between the hips was clinically and statistically significant (median difference 15.35 mm3, range 1 to 39 mm3, IQR 6 to 23 mm3) (p < 0.001). The median ratio of total wear volume between the hips was 2.0 (range 1.09 to 10.0, IQR 1.67 to 3.72). In majority of the histological features and in presence of pseudotumour, there were no differences between the left and right hip of each patient (p > 0.05 for all comparisons). These features included macrophage sheet thickness, perivascular lymphocyte cuff thickness, presence of plasma cells, presence of diffuse lymphocytic infiltration and presence of germinal centers.ConclusionsDespite the significantly differing amounts of wear (extrinsic factor) seen between the sides, majority of the histological findings were similar in both hips and the presence of pseudotumour was symmetrical in most hips. As a direct consequence, it follows that there must be intrinsic factors which contribute to the symmetry of the findings, ie. the pathogenesis of ARMD, on individual level. This has been hypothesized in the literature but no studies have been conducted to confirm the hypothesis. Further, as the threshold of metal debris needed to develop ARMD appears to be largely variable based on the previous literature, it is likely that there are between-patient differences in these intrinsic factors, ie. the host response to metal debris is individual.

Some Recent Advances on Statistical Approaches for Planning Multi-regional Clinical Trials

Many multi-regional clinical trials are faced with possible heterogeneity in treatment effect among regions and consequently the interpretation of the trial results is quite challenging. Regional heterogeneity can be caused by the differences in intrinsic factors, extrinsic factors or trial/data quality among regions. An apparent regional difference in treatment effect can be caused by a play of chance or sampling variability. In another aspect, regional heterogeneity may have substantial ramifications on sample size estimation for planning a multi-regional trial, as stipulated in Hung et al. (Pharm Stat 9:173–178, 2010), Lan and Pinheiro (Stat Biosci 14:235–244, 2012) and Quan et al. (Stat Med 33:2191–2205, 2014). Analyses of multi-regional trials are commonly based on a fixed-effect model assuming that the true treatment effects in all regions are equal in magnitude which may or may not be practical. Random-effect modelling has been considered as an alternative to deal with regional heterogeneity. In this research work we shall discuss the statistical implications of the statistical modelling approaches on the type I error probability and statistical power associated with testing the global treatment effect. We also develop formulae to assess the probability that some regions may falsely show an apparent negative trend by chance or sampling variability. As another alternative, a fixed-effect model that accounts for acceptable regional heterogeneity will be introduced.

Multilevel Analysis of Factors Predicting Self Efficacy in Computer Programming

This study used multilevel analysis to determine the predictive value of selected intrinsic factors (gender, computer ownership, mathematics background and computer experience) and institutional type (an extrinsic factor) on undergraduates’ Self Efficacy in Java Computer Programming (SEiJCP) in South – West, Nigeria. The study adopted a correlational design. Purposive Sampling was used to select 254 computer science undergraduates from four universities (three federal-owned and one state-owned) in south-west, Nigeria. Three research questions were answered. Two research instruments namely, Computer experience scale (r = 0.84) and Java Programming Self Efficacy Scale (JPSES, r = 0.96) were used to collect data. Data were analysed using descriptive statistics, and null and linear growth model (LGM) procedures. The intercorrelation coefficients among the extrinsic factor, intrinsic factors and SEiJCP were moderate. Null model shows that the variations in SEiJCP accounted for by insitutional level differences was 99.0%. The fixed part of the LGM of intrinsic factors showed that only mathematical backgroung contributed significantly (p < 0.05) to the prediction of SEiJCP. The random part of the LGM showed no significant contributions of the interactions of the intrinsic factors, to the prediction of SEiJCP. About 60.0% of the student level variation in SEiJCP is explained by the differences in intrinsic factors. The institution – level variable had large predictive value on programming self efficacy. Computer science departments should increase the number of mathematics courses in their curriculum.

Contrasting patterns of MAAs accumulation in two populations of the copepod Boeckella gracilipes

The bio-accumulation of mycosporine-like amino acids (MAAs) is common in planktonic copepods that inhabit environments exposed to high levels of solar radiation. MAAs accumulation in copepods can be affected both by extrinsic (environmental) and intrinsic factors (local adaptation, genotype, etc.). Laboratory experiments were performed to study the bio-accumulation of MAAs in two geographically-isolated populations of Boeckella gracilipes from a mountain and a piedmont lake of North Patagonia. We performed two series of 10-day incubations of B. gracilipes from the different lakes applying two radiation conditions (PAR + UVR and darkness), at five different temperatures (5 to 20 °C) and providing a MAA-free flagellate as food. We assumed that differences in final MAAs concentrations between copepod populations should be exclusively due to environmental factors, and that any difference in the patterns of MAAs accumulation should exclusively arise from differences in MAAs concentration at the time of collection. MAAs concentration was three fold higher in B. gracilipes from Lake Verde than in copepods from the Lake Morenito. The MAAs suite was dominated (∼90%) by a combination of porphyra-334 and mycosporine-glycine in copepods from Lake Verde, and porphyra-334 and MAA-332 in those from Lake Morenito. Two exclusive MAA compounds were identified, mycosporine-glycine in copepods from Lake Verde and shinorine in the copepod population from Lake Morenito. Laboratory experiments showed that: (i) exposure to PAR + UVR stimulated the accumulation of MAAs in both copepod populations; (ii) temperature affected the response of MAAs and, remarkably, low temperatures stimulated MAAs accumulation even in dark incubations, (iii) the response to radiation and temperature in MAAs accumulation was more pronounced in the population with low initial MAAs than in the population with high initial MAAs concentrations. The differences in intrinsic factors between B. gracilipes populations, such as local adaptation to contrasting UV and temperature scenarios, among others, appear to play an important role in determining levels and patterns of MAAs accumulation in B. gracilipes.

Prolonged expression and production of Staphylococcus aureus enterotoxin A in processed pork meat

The bacteriophage-encoded staphylococcal enterotoxin A (SEA) is the toxin most frequently reported to be involved in staphylococcal food poisoning. In this study, sea expression and SEA formation were studied in four processed pork products: boiled ham, hot-smoked ham, Serrano ham (dry-cured Spanish ham) and black pepper salami. The products were selected because of their differences in intrinsic factors. As a reference, Staphylococcus aureus was cultivated under favorable planktonic growth conditions. Expression was mainly linked to bacterial growth for both meat products and broth cultures. In liquid broth, however, the relative level of sea mRNA peaked in the late exponential phase and then rapidly declined, while in the meat products allowing immediate growth, i.e. boiled and smoked ham, active sea expression occurred throughout the incubation period of seven days. Lower levels of sea mRNA and SEA were found in smoked ham compared to boiled ham, although viable counts of S. aureus on the two products were similar. Furthermore, the SEA concentration in the boiled ham reached a maximum after three days of incubation and then unpredictably decreased. In the Serrano ham, no increase in cell number was observed until day seven, and sea expression and extracellular SEA could only be detected on days five and seven. Finally, the black pepper salami with low pH and competing microbiota proved to be a difficult environment for the survival of S. aureus. The molecular mechanism behind the behaviour of S. aureus SEA expression is discussed in connection to the life-cycle of the SEA-encoding bacteriophage and the microbial communities in these pork products.