Evaluation of mobility recovery after hip fracture: a scoping review of randomized controlled studies.

Few older adults regain their pre-fracture mobility after a hip fracture. Intervention studies evaluating effects on gait typically use short clinical tests or in-lab parameters that are often limited to gait speed only. Measurements of mobility in daily life settings exist and should be considered to a greater extent than today. Less than half of hip fracture patients regain their pre-fracture mobility. Mobility recovery is closely linked to health status and quality of life, but there is no comprehensive overview of how gait has been evaluated in intervention studies on hip fracture patients. The purpose was to identify what gait parameters have been used in randomized controlled trials to assess intervention effects on older people's mobility recovery after hip fracture. This scoping review is a secondary paper that identified relevant peer-reviewed and grey literature from 11 databases. After abstract and full-text screening, 24 papers from the original review and 8 from an updated search and manual screening were included. Records were eligible if they included gait parameters in RCTs on hip fracture patients. We included 32 papers from 29 trials (2754 unique participants). Gait parameters were primary endpoint in six studies only. Gait was predominantly evaluated as short walking, with gait speed being most frequently studied. Only five studies reported gait parameters from wearable sensors. Evidence on mobility improvement after interventions in hip fracture patients is largely limited to gait speed as assessed in a controlled setting. The transition from traditional clinical and in-lab to out-of-lab gait assessment is needed to assess effects of interventions on mobility recovery after hip fracture at higher granularity in all aspects of patients' lives, so that optimal care pathways can be defined.

Epstein-Barr virus infection after adolescence and human herpesvirus 6A as risk factors for multiple sclerosis.

BACKGROUND AND PURPOSE: Infections with human herpesvirus 6A (HHV-6A) and Epstein-Barr virus (EBV) have been linked to multiple sclerosis (MS) development. For EBV, late infection has been proposed as a risk factor, but serological support is lacking. The objective of this study was to investigate how age affects the EBV and HHV-6A associated risks of developing MS. METHODS: In this nested case-control study, Swedish biobanks were accessed to find pre-symptomatically collected blood samples from 670 individuals who later developed relapsing MS and 670 matched controls. A bead-based multiplex assay was used to determine serological response against EBV and HHV-6A. Conditional logistic regression was used to calculate odds ratios and 95% confidence intervals. RESULTS: Seropositivity against EBV exhibited a pattern where associations switched from a decreased risk of developing MS in the group below 20 years of age to an increased risk amongst individuals aged 20-29 and 30-39 years (p for trend 0.020). The age of transition was estimated to be 18.8 years. In contrast, HHV-6A was associated with increased MS risk in all age groups (total cohort odds ratio 2.1, 95% confidence interval 1.6-2.7). CONCLUSIONS: This study suggests EBV infection after adolescence and age independent HHV-6A infection as risk factors for MS.

Timing of HPV16-E6 antibody seroconversion before OPSCC: findings from the HPVC3 consortium.

BACKGROUND: Human papillomavirus type 16 (HPV16)-E6 antibodies are detectable in peripheral blood before diagnosis in the majority of HPV16-driven oropharyngeal squamous cell carcinoma (OPSCC), but the timing of seroconversion is unknown. PATIENTS AND METHODS: We formed the HPV Cancer Cohort Consortium which comprises nine population cohorts from Europe, North America and Australia. In total, 743 incident OPSCC cases and 5814 controls provided at least one pre-diagnostic blood sample, including 111 cases with multiple samples. Median time between first blood collection and OPSCC diagnosis was 11.4 years (IQR = 6-11 years, range = 0-40 years). Antibodies against HPV16-E6 were measured by multiplex serology (GST fusion protein based Luminex assay). RESULTS: HPV16-E6 seropositivity was present in 0.4% of controls (22/5814; 95% CI 0.2% to 0.6%) and 26.2% (195/743; 95% CI 23.1% to 29.6%) of OPSCC cases. HPV16-E6 seropositivity increased the odds of OPSCC 98.2-fold (95% CI 62.1-155.4) in whites and 17.2-fold (95% CI 1.7-170.5) in blacks. Seropositivity in cases was more frequent in recent calendar periods, ranging from 21.9% pre-1996 to 68.4% in 2005 onwards, in those with blood collection near diagnosis (lead time <5 years). HPV16-E6 seropositivity increased with lead time: 0.0%, 13.5%, 23.7%, and 38.9% with lead times of >30 years (N = 24), 20-30 years (N = 148), 10-20 years (N = 228), and <10 years (N = 301 cases) (p-trend < 0.001). Of the 47 HPV16-E6 seropositive cases with serially-collected blood samples, 17 cases seroconverted during follow-up, with timing ranging from 6 to 28 years before diagnosis. For the remaining 30 cases, robust seropositivity was observed up to 25 years before diagnosis. CONCLUSIONS: The immune response to HPV16-driven tumorigenesis is most often detectable several decades before OPSCC diagnosis. HPV16-E6 seropositive individuals face increased risk of OPSCC over several decades.

Fluctuations-induced coexistence in public goods dynamics.

Cooperative interactions between individuals in a population and their stability properties are central to population dynamics and evolution. We introduce a generic class of nonlinear dynamical systems describing such interactions between producers and non-producers of a rapidly equilibrating common resource extracted from a finite environment. In the deterministic mean field approximation, fast-growing non-producers drive the entire population to extinction. However, the presence of arbitrarily small perturbations destabilizes this fixed point into a stochastic attractor where both phenotypes can survive. Phase space arguments and moment closure are used to characterize the attractor and show that its properties are not determined by the noise amplitude or boundary conditions, but rather it is stabilized by the stochastic nonlinear dynamics. Spatial Monte Carlo simulations with demographic fluctuations and diffusion illustrate a similar effect, supporting the validity of the two-dimensional stochastic differential equation as an approximation. The functional distribution of the noise emerges as the main factor determining the dynamical outcome. Noise resulting from diffusion between different regions, or additive noise, induce coexistence while multiplicative or local demographic noise do not alter the outcome of deterministic dynamics. The results are discussed in a general context of the effect of noise on phase space structure.

Transients and tradeoffs of phenotypic switching in a fluctuating limited environment.

Phenotypic variability in a microorganism population is thought to be advantageous in fluctuating environments, however much remains unknown about the precise conditions for this advantage to hold. In particular competition for a growth-limiting resource and the dynamics of that resource in the environment modify the tradeoff between different effects of variability. Here we investigate theoretically a model system for variable populations under competition for a flowing resource that governs growth (chemostat model) and changes with time. This environment generally induces density-dependent selection among competing sub-populations. We characterize quantitatively the transient dynamics in this system, and find that equilibration between total population density and environment can occur separately and with a distinct timescale from equilibration between competing sub-populations. We analyze quantitatively the two opposing effects of heterogeneity--transient response to change, and fitness at equilibrium--and find the optimal strategy in a fluctuating environment. We characterize the phase diagram of the system in term of its optimal strategy and find it to be strongly dependent on the typical timescale of the environment and weakly dependent on the internal parameters of the population.

Human genomics of the humoral immune response against polyomaviruses.

Human polyomaviruses are widespread in humans and can cause severe disease in immunocompromised individuals. To identify human genetic determinants of the humoral immune response against polyomaviruses, we performed genome-wide association studies and meta-analyses of qualitative and quantitative immunoglobulin G responses against BK polyomavirus (BKPyV), JC polyomavirus (JCPyV), Merkel cellpolyomavirus (MCPyV), WU polyomavirus (WUPyV), and human polyomavirus 6 (HPyV6) in 15,660 individuals of European ancestry from three independent studies. We observed significant associations for all tested viruses: JCPyV, HPyV6, and MCPyV associated with human leukocyte antigen class II variation, BKPyV and JCPyV with variants in FUT2, responsible for secretor status, MCPyV with variants in STING1, involved in interferon induction, and WUPyV with a functional variant in MUC1, previously associated with risk for gastric cancer. These results provide insights into the genetic control of a family of very prevalent human viruses, highlighting genes and pathways that play a modulating role in human humoral immunity.

Retroactive interference in discrimination learning.

In stage 1 of this experiment pigeons were trained to discriminate between two levels of noise or two colors by pecking on one of two disks. In stage 2 the discriminative stimuli were not presented, but pecking on the disks was rewarded on a random schedule. The second procedure caused the pigeons to forget the discrimination they had learned.

Investigation of the content and of the distribution of chemical elements in human nails by SRXRF.

The purpose of this investigation is to analyze 20 nails in individuals (and several persons) for the definition of how chemical elements distribute from nail to nail. The aim was to determine whether it will be rightful to take only one nail for the elemental analysis for the diagnostic of human state in future or not? Another purpose of the research is to analyze the elemental content of nails in temporal dynamic (in several persons). Analytical determinations of 20 nails of nine donors (healthy persons), nails of both hands and both feet were carried out. The analysis was performed by SRXRF. Symmetry of the elemental distribution in nails of right and left hands and right and left feet was found. The analysis of the distribution of chemical elements on the total area of a nail (55 points) was performed. The nail cutaway reflects adequately the distribution of several chemical elements over the nail plate area. In this study the elemental concentrations in nails of three donors in a 6-month period was determined. This study found the content of the chemical elements in donors' nails changes with time, individually.

Development and validation of HIV-1 Multiplex Serology.

By inducing immunosuppression in infected patients, human immunodeficiency virus-1 (HIV-1) generates a favorable environment for opportunistic infections and the development of several human cancers. In order to detect individual serum or plasma HIV-1 antibody status for epidemiological studies, high-throughput HIV-1 Multiplex Serology was developed. Seven HIV-1 antigens were recombinantly expressed in E. coli as N-terminal glutathione-S-transferase (GST) fusion proteins that are bound to glutathione-coupled sets of beads with distinct fluorescent color. Combining all bead sets in a suspension array allowed for simultaneous detection of antibodies targeting structural, regulatory and accessory proteins expressed during HIV-1 infection. HIV-1 Multiplex Serology was validated with 244 reference sera whose HIV-1 serostatus had been pre-determined by screening microparticle immunoassay and confirmatory line immunoassay. The multifunctional protein GAG emerged as an excellent marker to determine HIV-1 serostatus with a specificity of 99% (95% CI 96%-100%) and sensitivity of 100% (95% CI 88%-100%). Seropositivity for multiple HIV-1 antigens appeared to be characteristic for HIV-1 infected individuals (median number of antigens recognized in reference assay positive sera: 4; median number of antigens recognized in reference assay negative sera: 0), indicating a broad immune response targeting also regulatory and accessory proteins which may be useful for the identification of antibody patterns specific for infection-associated disease stages. HIV-1 Multiplex Serology performs similarly to conventional HIV-1 serology but eliminates the need for a two-step screening approach with subsequent confirmation assay. Thus, this high-throughput method will facilitate large-scale epidemiological studies of the role of HIV-1 in cancer development.

Adaptive rescaling maximizes information transmission.

Adaptation is a widespread phenomenon in nervous systems, providing flexibility to function under varying external conditions. Here, we relate an adaptive property of a sensory system directly to its function as a carrier of information about input signals. We show that the input/output relation of a sensory system in a dynamic environment changes with the statistical properties of the environment. Specifically, when the dynamic range of inputs changes, the input/output relation rescales so as to match the dynamic range of responses to that of the inputs. We give direct evidence that the scaling of the input/output relation is set to maximize information transmission for each distribution of signals. This adaptive behavior should be particularly useful in dealing with the intermittent statistics of natural signals.

Selective IgA deficiency in blood donors.

The frequency of selective IgA deficiency was determined in a healthy population of 6,240 blood donors. Screening for IgA deficiency was performed by double-diffusion analysis in agarose gel. Confirmation testing was performed with the more sensitive passive hemagglutination inhibition assay. Prevalence of IgA deficiency, characterized by a serum level of below 50 mg/L, was 0.30% (1 in 328), which is the highest prevalence of selective IgA deficiency reported in a healthy population. Antibodies to IgA were detected in sera of 36.8% of the blood donors with selective IgA deficiency, which also is the highest prevalence of anti-IgA antibodies reported in any previous study. The literature on IgA deficiency in healthy populations is reviewed. Current concepts in treatment of IgA-deficient patients requiring blood products are described.

Receptor binding radiotracers for the angiotensin II receptor: radioiodinated [Sar1, Ile8]Angiotensin II.

The potential for imaging the angiotensin II receptor was evaluated using the radioiodinated peptide antagonist [125I][Sar1, Ile8)angiotensin II. The radioligand provides a receptor-mediated signal in several tissues in rat (kidneys, adrenal and liver). The receptor-mediated signal of 3% ID/g kidney cortex should be sufficient to permit imaging, at least via SPECT. The radiotracer is sensitive to reductions in receptor concentration and can be used to define in vivo dose-occupancy curves of angiotensin II receptor ligands. Receptor-mediated images of [123I][Sar1, Ile8]angiotensin II were obtained in the rat kidney and Rhesus monkey liver.

Characterization of the binding of [125I]L-735,286: a new nonpeptide angiotensin II AT1 receptor radioligand.

[125I]L-735,286, a new potent and AT1-selective nonpeptide angiotensin II receptor radioligand, bound saturably to whole adrenal membranes. Scatchard and Hill plot analysis indicates a single class of high affinity (Kd = 0.5 nM) binding sites. The potencies of various angiotensin II agonists and antagonists in displacing specific [125I]L-735,286 binding are in good agreement with their potencies in displacing the binding of [125I]Sar1,Ile8-AII to adrenal AT1 receptors. The AT2 selective ligand, PD121981 had no effect on specific [125I]L-735,286 binding. In autoradiographic studies using rat kidney slices, specific labeling of [125I]L-735,286 was abolished by coincubation with saralasin. Collectively, the data indicated that [125I]L-735,286 represents a new, potent nonpeptide antagonist radioligand suitable for the study of angiotensin II AT1 receptors.

[125I]PIP HOE 140, a high affinity radioligand for bradykinin B2 receptors.

A high affinity radioligand for bradykinin B2 receptors was prepared by coupling an activated ester of [125I]4-iodobenzoic acid to the amino terminus nitrogen of the potent B2 antagonist HOE 140. The ligand, [125I]para-iodophenyl HOE 140 ([125I]PIP HOE 140), bound to a homogeneous set of sites in guinea pig ileal membranes with an equilibrium dissociation constant of 15 pM and a maximal binding density of 193 fmole/mg protein. Competition studies with a number of BK-related peptides indicated that the ligand specifically labeled B2 receptors in the preparation. The results suggest that [125I]PIP HOE 140 will be a useful tool for future studies of B2 receptors.