The effect of salt on the Michaelis Menten constant of the HIV-1 protease correlates with the Hofmeister series

The effect of different types of salt on the proteolytic activity of HIV-1 protease was studied. At a similar ionic strength, the enzyme activity changed according to the salting out effect of the ions used (Hofmeister series). Kinetic studies showed that a stronger salting out effect of the ions rather than the higher ionic strength per se increased the affinity to the substrate (Km) but in general did not alter the Kcat value.     

Contralateral effects of unilateral strength training: evidence and possible mechanisms.

If exercises are performed to increase muscle strength on one side of the body, voluntary strength can increase on the contralateral side. This effect, termed the contralateral strength training effect, is usually measured in homologous muscles. Although known for over a century, most studies have not been designed well enough to show a definitive transfer of strength that could not be explained by factors such as familiarity with the testing. However, an updated meta-analysis of 16 properly controlled studies (range 15-48 training sessions) shows that the size of the contralateral strength training effect is approximately 8% of initial strength or about half the increase in strength of the trained side. This estimate is similar to results of a large, randomized controlled study of training for the elbow flexors (contralateral effect of 7% initial strength or one-quarter of the effect on the trained side). This is likely to reflect increased motoneuron output rather than muscular adaptations, although most methods are insufficiently sensitive to detect small muscle contributions. Two classes of central mechanism are identified. One involves a "spillover" to the control system for the contralateral limb, and the other involves adaptations in the control system for the trained limb that can be accessed by the untrained limb. Cortical, subcortical and spinal levels are all likely to be involved in the "transfer," and none can be excluded with current data. Although the size of the effect is small and may not be clinically significant, study of the phenomenon provides insight into neural mechanisms associated with exercise and training.     

Long Term Effect on Professionals’ Knowledge,Practice and Attitudes towards User Involvement Four Years after Implementing an Organisational Development Plan: A Controlled Study

Background

Health service organisations are increasingly implementing user involvement initiatives according to requirements from governments, such as user representation in administrational boards, better information to users, and more involvement of the users during treatment. Professionals are vital in all initiatives to enhance user involvement, and initiatives to increase involvement should influence the professionals’ practice and attitudes. The implementation of a development plan intending to enhance user involvement in a mental health hospital in Central Norway had no effect on the professionals after 16 months. The objective was therefore to investigate the long term effect on the professionals’ knowledge, practice and attitudes towards user involvement after four years.

Methods

This was a non-randomized controlled study including professionals from three mental health hospitals in Central Norway. A development plan intended to enhance user participation was implemented in one of the hospitals, including establishing a patient education centre and a user office, purchasing of user expertise, appointing contact professionals for next of kin, and improving of the centre’s information and the professional culture. The professionals at two other hospitals constituted the control group. All professionals were invited to answer the Consumer Participation Questionnaire (CPQ) and additional questions, at a four year interval.

Results

A total of 399 professionals participated (43% response rate). Comparing the changes in the intervention group with the changes in the control group, the results showed that the plan had improved some aspects of the professionals’ knowledge about the user involvement taking place in the hospital. In addition, some parts of the professionals’ practice of providing information to the service users was improved, and the development plan might have raised their awareness about insufficient involvement of next of kin.

Conclusions

This is the first controlled study on the long term effect on professionals from implementing a development plan to enhance user participation in a mental health hospital. Since there was more effect after four years than after 16 months, this study indicates that it takes time before the effect of complex interventions to enhance patient participation in organisations can be detected among the professionals. More long-term studies are thus warranted.     

Facing decisions about life and death--communication with parents

How can healthcare professionals, most of whom have never personally been confronted with such tragic situations, best help parents and their children make decisions about life and death that will minimize the suffering of children and their parents? Research studies and the professional experience of those attuned to these problems can be instructive. This paper reviews and gives advice about the communication between healthcare professionals and parents and children facing life and death.     

Implementation of asymmetric yielding in case-specific finite element models improves the prediction of femoral fractures

Although asymmetric yielding in bone is widely shown in experimental studies, previous case-specific non-linear finite element (FE) studies have mainly adopted material behaviour using the Von Mises yield criterion (VMYC), assuming equal bone strength in tension and compression. In this study, it was verified that asymmetric yielding in FE models can be captured using the Drucker-Prager yield criterion (DPYC), and can provide better results than simulations using the VMYC. A sensitivity analysis on parameters defining the DPYC (i.e. the degree of yield asymmetry and the yield stress settings) was performed, focusing on the effect on bone failure. In this study, the implementation of a larger degree of yield asymmetry improved the prediction of the fracture location; variations in the yield stress mainly affected the predicted failure force. We conclude that the implementation of asymmetric yielding in case-specific FE models improves the prediction of femoral bone strength.     

Contralateral effects of unilateral resistance training: a meta-analysis.

It is often claimed that strength training of one limb increases the strength of the contralateral limb, but this has not been demonstrated consistently, particularly in well-controlled studies. The aim was to quantitatively combine the results of other studies on the effects of unilateral training on contralateral strength in humans to provide an answer to this physiological question. We analyzed all randomized controlled studies of voluntary unilateral resistance training that used training intensities of at least 50% of maximal voluntary strength for a minimum of 2 wk. Studies were identified by computerized and hand searches of the literature. Data on changes in strength of contralateral and control limbs were extracted and statistically pooled in a meta-analysis. This approach allows conclusions to be based on a statistically meaningful sample size, which might be difficult to achieve in other ways. Seventeen studies met the inclusion criteria, and 13 provided enough data for statistical pooling. The contralateral effects of strength training reported in individual studies varied from -2.7 to 21.6% of initial strength. The pooled estimate of the effect of unilateral resistance training on the maximal voluntary strength of the contralateral limb was 7.8% (95% confidence interval: 4.1-11.6%). This was 35.1% (95% confidence interval: 20.9-49.3%) of the effect on the trained limb. Pooling of all available data shows that unilateral strength training produces modest increases in contralateral strength.     

Characterization of the differences in strength and power between different levels of competition in rugby union athletes

ABSTRACT: Argus, CK, Gill, ND, and Keogh, JWL. Characterization of the differences in strength and power between different levels of competition in rugby union athletes. J Strength Cond Res 26(10): 2698-2704, 2012-Levels of strength and power have been used to effectively discriminate between different levels of competition; however, there is limited literature in rugby union athletes. To assess the difference in strength and power between levels of competition, 112 rugby union players, including 43 professionals, 19 semiprofessionals, 32 academy level, and 18 high school level athletes, were assessed for bench press and box squat strength, and bench throw, and jump squat power. High school athletes were not assessed for jump squat power. Raw data along with data normalized to body mass with a derived power exponent were log transformed and analyzed. With the exception of box squat and bench press strength between professional and semiprofessional athletes, higher level athletes produced greater absolute and relative strength and power outputs than did lower level athletes (4-51%; small to very large effect sizes). Lower level athletes should strive to attain greater levels of strength and power in an attempt to reach or to be physically prepared for the next level of competition. Furthermore, the ability to produce high levels of power, rather than strength, may be a better determinate of playing ability between professional and semiprofessional athletes.     

Trans-generational immune priming is not mediated by the sex of the parent primed: a meta-analysis of invertebrate data

Traditionally, only vertebrates were thought capable of acquired immune responses, such as the ability to transfer immunological experience vertically to their offspring (known as trans-generational immune priming, TGIP). Increasing evidence challenges this belief and it is now clear that invertebrates also have the ability to exhibit functionally equivalent TGIP. This has led to a surge in papers exploring invertebrate TGIP, with most focusing on the costs, benefits or factors that affect the evolution of this trait. Whilst many studies have found support for the phenomenon, not all studies do, and there is considerable variation in the strength of positive results. To address this, we conducted a meta-analysis to answer the question: what is the overall effect of TGIP in invertebrates? Then, to understand the specific factors that affect its presence and intensity, we conducted a moderator analysis. Our results corroborate that TGIP occurs in invertebrates (demonstrated by a large, positive effect size). The strength of the positive effect was related to if and how offspring were immune challenged (i.e. whether they were challenged with the same or different insult as their parents or not challenged at all). Interestingly, there was no effect of the ecology or life history of the species or the sex of the parent or the offspring primed, and responses were comparable across different immune elicitors. Our publication bias testing suggests that the literature may suffer from some level of positive-result bias. However, even after accounting for potential bias, our effect size remains positive. Publication bias testing can be influenced by diversity in the data set, which was considerable in our data, even after moderator analysis. It is therefore conceivable that differences among studies could be caused by other moderators that were unable to be included in our meta-analysis. Nonetheless, our results suggest that TGIP does occur in invertebrates, whilst providing some potential avenues to examine the factors that account for variation in effect sizes.     

Cation-induced regulatory mechanism of GTPase activity dependent on polypeptide initiation factor 2.

Initiation factor IF-2 ribosome dependent GTP hydrolysis (uncoupled GTPase) presents a bell-shaped pH profile which is shifted by changes in ionic strength. At low ionic strength (I = 25 mM) the maximal hydrolytic activity occurs at pH 7.5; when the ionic strength is increased the pH optimum of the reaction is shifted toward more acidic values. Such behavior can be satisfactorily explained as the effect of an electrostatic potential developed by a neighboring polyanion, presumably RNA, on the catalytic site. The addition of fMet-tRNAfMet or AcPhe-tRNAPhe and messenger RNA (coupled GTPase) changes the ionic strength--pH characteristics of the reaction. Thus there is an effect, direct or indirect, of components located at the ribosomal P site. Investigation of the effect of neighboring polyanions on the catalytic activity of the factor-dependent ribosomal GTPases can be seen to provide information about their functional significance that is complementary to that gained from direct structural studies.     

Intranasal M Cell Uptake of Nanoparticles Is Independently Influenced by Targeting Ligands and Buffer Ionic Strength

In mucosal tissues, epithelial M cells capture and transport microbes across the barrier to underlying immune cells. Previous studies suggested that high affinity ligands targeting M cells may be used to deliver mucosal vaccines; here, we show that particle composition and dispersion buffer ionic strength can independently influence their uptake in vivo. First, addition of a poloxamer 188 to nanoparticle formulations increased uptake of intranasally administered nanoparticles in vivo, but the effect was dependent on the presence of the M cell-targeting ligand. Second, solvent ionic strength is known to effect electrostatic interactions; accordingly, reduced ionic strength increased the electrostatic potential between the epithelium and the particles. Interestingly, below a critical ionic strength, intranasal particle uptake in vivo significantly was increased even when controlled for osmolarity. Similar results were obtained for uptake of bacterial particles. Surprisingly, at low ionic strength, the specific enhancement effect by the targeting peptide was negligible. Modeling of the electrostatic forces predicted that the enhancing effects of the M cell-targeting ligand only are enabled at high ionic strength, as particle electrostatic forces are reduced through Debye screening. Thus, electrostatic forces can have a dramatic effect on the in vivo M cell particle uptake independent of the action of targeting ligands. Examination of these forces will be helpful to optimizing mucosal vaccine and drug delivery.     

Quantifying the interaction structure and the topological importance of species in food webs: A signed digraph approach

Due to the structural complexity of nature, it is not always easy to identify topologically importance species in an ecosystem. In the past decade, several studies in ecology have developed methods for measuring species importance basing on direct and indirect inter-specific interactions. Here, by extending a previously developed methodology, we present an approach that can quantify the interaction structure of a food web and consequently the topological importance of species when the food web is viewed as a signed digraph. The basic principle behind our approach is to determine the sign and strength of direct and indirect interactions for all pathways up to a predefined number of steps. Our approach mainly differs from the previous methodology in that we are able to quantify the strength of inter-specific interaction as well as in what way species interact with each other, as it can explicitly quantify a wide range of ecological interactions such as cascading effect, indirect food supply effect, apparent and exploitive competitions in the same framework. This then allows us to quantify the topological importance of a species and examine whether it is a predominately positive or negative interactor in a food web. Furthermore, our analysis reveals that positive and negative effects from one species on others eventually cancel each other out for longer pathways resulting in stable interaction structure. Applications of our methodology include providing a more informative index for conservation biologists, and the potential use of interaction structure derived from our approach in food web robustness studies is also discussed.     

Effects of electromyographic biofeedback on quadriceps strength: a systematic review

Quadriceps strength is a vital component to lower extremity function and is often the focus in resistance training interventions and injury rehabilitation. Electromyographic biofeedback (EMGBF) is frequently used to supplement strength gains; however, the true effect remains unknown. Therefore, the objective of this investigation was to determine the magnitude of the treatment effect for EMGBF on quadriceps strength compared with that of placebo and traditional exercise interventions in both healthy and pathological populations. Web of Science and ProQuest databases were searched, and bibliographies of relevant articles were crossreferenced. Six articles measuring isometric quadriceps strength in response to EMGBF training were included and methodologically assessed using the Physiotherapy Evidence Database (PEDro). Standardized effect sizes with 95% confidence intervals (CIs) were calculated from preintervention and postintervention measures for EMGBF, placebo, and exercise-only interventions. Separate comparisons were made between studies assessing different intervention length (<4 and ≥4 weeks) and patient populations (pathological and healthy). Articles included received an average PEDro score of 6.5 ± 0.84. Homogeneous EMGBF effect sizes were found in all 6 studies (d = 0.01-5.56), with 4 studies reporting CI that crossed 0. A heterogeneous collection of effect sizes was found for exercise alone (d = -0.12 to 1.18) and placebo (d = -0.2 to 1.38), with 4 and 1 studies having a CI that crossed 0, respectively. The greatest EMGBF effects were found in pathological populations (d = 0.01-5.56), with the strongest effect found in the subjects with knee osteoarthritis (d = 5.56, CI = 4.26-6.68). As a group, effects were the strongest for EMGBF compared with that of placebo and exercise-only interventions, yet definitive evidence that EMGBF is beneficial for increasing quadriceps strength could not be concluded because of the 4 studies demonstrating a wide CI.     

Suppressive actions of inorganic ions on the bioactivity of aminoglycoside antibiotics.

Many independent studies have shown that inorganic salts can suppress the inhibitory activities of aminoglycoside antibiotics against various bacterial species. From studies on the nature and mechanism of this suppressive ion effect, several conclusions can be drawn. Both monovalent and divalent cation salts can inhibit aminoglycoside action. At least two different mechanisms are apparently involved. The first is divalent cation dependent and has been described with $\text{Pseudomonas aeruginosa}$ and $\text{Mycobacterium smegmatis}$. With $\text{M. smegmatis}$, the effect aappears to be dependent more on a double positive charge than on particular metal ion species. The second mechanism is related to ionic strength and is elicited by both monovalent and divalent cation salts against many different organisms. However, based on studies with $\text{M. smegmatis}$, it appears that each of the two mechanisms involves interferance with the initial instantaneous electrostatic binding of drug at the cell surface.     

Maximal strength testing in healthy children

Strength training has become an accepted method of conditioning in children. However, there is concern among some observers that maximal strength testing may be inappropriate or potentially injurious to children. The purpose of this study was to evaluate the safety and efficacy of 1 repetition maximum (1RM) strength testing in healthy children. Thirty-two girls and 64 boys between 6.2 and 12.3 years of age (mean age 9.3 +/- 1.6 years) volunteered to participate in this study. All subjects were screened for medical conditions that could worsen during maximal strength testing. Under close supervision by qualified professionals, each subject performed a 1RM test on 1 upper-body (standing chest press or seated chest press) and 1 lower-body (leg press or leg extension) exercise using child-size weight training machines. No injuries occurred during the study period, and the testing protocol was well tolerated by the subjects. No gender differences were found for any upper- or lower-body strength test. These findings demonstrate that healthy children can safely perform 1RM strength tests, provided that appropriate procedures are followed.     

Attitudes towards carrier testing in minors: a systematic review

The objective of this article is to review the attitudes of the different stakeholders (minors, healthcare professionals, parents and relatives of affected individuals) towards carrier testing in minors. The databases Pubmed, Google Scholar, Psychinfo, Biological Abstracts, Francis, Anthropological Index online, Web of Science, and Sociological Abstracts were searched using key words for the period 1990-2004. Studies were included if they were published in a peer reviewed journal in English and described the attitudes of minors, parents or healthcare professionals towards carrier testing in minors in a family context. The results were presented in a summary form. In total 20 relevant studies were retrieved (2 studies reported the attitudes of two stakeholders). Only one study reported the attitudes of adolescents, two studies reported the attitudes of adults who had undergone carrier testing in childhood. In total six studies have been retrieved discussing the parental attitudes towards carrier testing in their children. Over all studies, most parents showed interest in detecting their children's carrier status and responded they wanted their child tested before the age of majority: some parents even before 12 years. Eight studies were retrieved that reported the attitudes of relatives of affected individuals. Most were in favor of carrier testing before 18 years. The studies retrieved suggest that most parents are interested in the carrier status of their children and want their children to be tested before they reach legal majority (and some even in childhood). This can lead to tensions between parents and healthcare professionals regarding carrier testing in minors. Guidelines of healthcare professionals advise to defer carrier testing on the grounds that children should be able to decide for themselves later in life to request a carrier test or not.     

Mutations in the BRCA1 gene: implications of inter-population differences for predicting the risk of radiation-induced breast cancers

The effects of cancer predisposition and increased tumorigenic radiosensitivity of the predisposed genotypes on radiation cancer risks (in the general population and in sisters and first cousins of affected probands) are studied using an autosomal dominant model of cancer predisposition and radiosensitivity. The model assumes that the predisposing alleles, which confer enhanced tumorigenic radiosensitivity, are incompletely penetrant. In addition, the model also allows for sporadic cancers, unrelated to the predisposing locus. The predictions of the model are illustrated using current estimates of BRCA1 mutant gene frequencies; the estimates of the strength of predisposition and radiosensitivity differentials used are based on animal and human studies. It is shown that, unless both the strength of predisposition and radiosensitivity differential are large (say, > 100-fold in comparison with normal homozygotes), (i) the effect of risk heterogeneity on cancer risk is marginal; (ii) dose-dependent radiation effect remains virtually the same as in a homogeneous irradiated population that has no predisposed subgroups; (iii) for the same radiation dose, relatives of affected probands show an enhancement of cancer risks; and (iv) most extra cancers in relatives can be attributed to radiosensitivity differentials. This simple model can give an upper bound of the effect of risk heterogeneity on radiation-induced breast cancer risks even when the cumulative breast cancer risk is age-dependent. Further, our model predicts that the benefits of mammography outweigh the risks.     

Sports performance graduate program interest and need survey: a brief report from the NSCA Education Committee

The Education Recognition Program (ERP) was developed to acknowledge academic institutions meeting departmental criteria established by the National Strength and Conditioning Association (NSCA) for having an area of concentration in undergraduate strength and conditioning. Since its inception, over 40 universities have received recognition status. The NSCA is currently examining the interest, need, and feasibility of creating an ERP for graduate curriculum specific to sports performance. The current investigation included a survey of Division I, II, and III strength and conditioning professionals. Surveys were mailed to 215 coaches, of which 53 responded (26% rate of return). Five factors were extracted from the questionnaire and were subsequently named: Application of Science to Strength and Conditioning, Professional Development, Graduate Curriculum Support, Graduate Program Requirements, and Graduate Assistantships. A one-way analysis of variance (ANOVA) found significant differences on Application of Science to Strength and Conditioning and Professional Development when comparing highest degree earned. Pairwise analysis indicated that individuals with Master's degrees scored those factors higher compared with individuals with Bachelor's degrees. The results from this survey provide initial information from current strength and conditioning professionals regarding the interest and need for developing formalized graduate curriculum specifically for sports performance.