The role of social context in symptom appraisal and help-seeking among people with lung or colorectal symptoms: A qualitative interview study.

Prolonged diagnostic intervals are associated with poorer outcomes, and the patient interval appears to be a substantial contributor to the overall length of the diagnostic interval. This study sought to understand how the broader context of people's lives influenced symptom appraisal and help-seeking, comparing experiences by length of the patient interval. Patients referred with a suspicion of lung or colorectal cancer were invited to complete a questionnaire about their symptoms, with 26 respondents purposively sampled to take part in a semi-structured interview about their patient intervals. Embodied experience, appraisal, help-seeking decision-making and consultation were identified as component stages of the patient interval, with the factors affecting movement between these stages located in one of four contextual domains: individual experience, interpersonal relationships, healthcare system interactions and social and temporal context. The length of the patient interval was related to the type of symptom(s) experienced, discussion of symptoms with others and the social responsibilities people held during symptomatic periods. A contextual model of the patient interval illustrates the stages and domains of this interval, as grounded in the data from this study. The model has potential application to future studies examining the patient interval for a range of symptoms.

Symptoms and other factors associated with time to diagnosis and stage of lung cancer: a prospective cohort study.

BACKGROUND: This prospective cohort study aimed to identify symptom and patient factors that influence time to lung cancer diagnosis and stage at diagnosis. METHODS: Data relating to symptoms were collected from patients upon referral with symptoms suspicious of lung cancer in two English regions; we also examined primary care and hospital records for diagnostic routes and diagnoses. Descriptive and regression analyses were used to investigate associations between symptoms and patient factors with diagnostic intervals and stage. RESULTS: Among 963 participants, 15.9% were diagnosed with primary lung cancer, 5.9% with other thoracic malignancies and 78.2% with non-malignant conditions. Only half the cohort had an isolated first symptom (475, 49.3%); synchronous first symptoms were common. Haemoptysis, reported by 21.6% of cases, was the only initial symptom associated with cancer. Diagnostic intervals were shorter for cancer than non-cancer diagnoses (91 vs 124 days, P=0.037) and for late-stage than early-stage cancer (106 vs 168 days, P=0.02). Chest/shoulder pain was the only first symptom with a shorter diagnostic interval for cancer compared with non-cancer diagnoses (P=0.003). CONCLUSIONS: Haemoptysis is the strongest symptom predictor of lung cancer but occurs in only a fifth of patients. Programmes for expediting earlier diagnosis need to focus on multiple symptoms and their evolution.

Identification of the gene responsible for methylmalonic aciduria and homocystinuria, cblC type.

Methylmalonic aciduria and homocystinuria, cblC type (OMIM 277400), is the most common inborn error of vitamin B(12) (cobalamin) metabolism, with about 250 known cases. Affected individuals have developmental, hematological, neurological, metabolic, ophthalmologic and dermatologic clinical findings. Although considered a disease of infancy or childhood, some individuals develop symptoms in adulthood. The cblC locus was mapped to chromosome region 1p by linkage analysis. We refined the chromosomal interval using homozygosity mapping and haplotype analyses and identified the MMACHC gene. In 204 individuals, 42 different mutations were identified, many consistent with a loss of function of the protein product. One mutation, 271dupA, accounted for 40% of all disease alleles. Transduction of wild-type MMACHC into immortalized cblC fibroblast cell lines corrected the cellular phenotype. Molecular modeling predicts that the C-terminal region of the gene product folds similarly to TonB, a bacterial protein involved in energy transduction for cobalamin uptake.

Chaperone proteins select and maintain [PIN+] prion conformations in Saccharomyces cerevisiae.

Prions are proteins that can adopt different infectious conformations known as "strains" or "variants," each with a distinct, epigenetically inheritable phenotype. Mechanisms by which prion variants are determined remain unclear. Here we use the Saccharomyces cerevisiae prion Rnq1p/[PIN(+)] as a model to investigate the effects of chaperone proteins upon prion variant determination. We show that deletion of specific chaperone genes alters [PIN(+)] variant phenotypes, including [PSI(+)] induction efficiency, Rnq1p aggregate morphology/size and variant dominance. Mating assays demonstrate that gene deletion-induced phenotypic changes are stably inherited in a non-Mendelian manner even after restoration of the deleted gene, confirming that they are due to a bona fide change in the [PIN(+)] variant. Together, our results demonstrate a role for chaperones in regulating the prion variant complement of a cell.

Spatial propagation of protein polymerization.

We consider the spatial dependence of filamentous protein self-assembly. Through studying the cases where the spreading of aggregated material is dominated either by diffusion or by growth, we derive analytical results for the spatial evolution of filamentous protein aggregation, which we validate against Monte Carlo simulations. Moreover, we compare the predictions of our theory with experimental measurements of two systems for which we identify the propagation as either growth or diffusion controlled. Our results connect the macroscopic observables that characterize the spatial propagation of protein self-assembly with the underlying microscopic processes and provide physical limits on spatial propagation and prionlike behavior associated with protein aggregation.

From pelvic radiation to social isolation: a qualitative study of survivors' experiences of chronic bowel symptoms after pelvic radiotherapy.

PURPOSE: We explored survivors' experiences of chronic bowel symptoms following pelvic radiotherapy, strategies employed in living with these symptoms, effects on daily activities, and roles at home and in the workplace. METHODS: Semi-structured interviews were conducted with 28 individuals (10 gynaecological, 14 prostate, four anal/rectal cancer survivors) who had completed pelvic radiotherapy at least six months prior to data collection and who had experience of bowel symptoms during this post-treatment period. Reflexive thematic analysis was undertaken. RESULTS: We propose four themes describing a process leading from experience of symptoms to withdrawal from activities and roles. These are (1) losing control (the experience of unintended anal leakage or discharge); (2) experiencing embarrassment and fear (the experience of embarrassment or fear of embarrassment as a result of discharge becoming public); (3) managing and reacting (acting to reduce the likelihood of discharge or to prevent this becoming public); and (4) restriction and withdrawal (avoiding specific activities or situations so as to reduce or remove the risk of embarrassment). Returning to the workplace presented additional challenges across these themes. CONCLUSIONS: Impacts of chronic bowel symptoms can be severe. Survivors employ a variety of methods and strategies in living with their symptoms. Some of these support continued role fulfilment but some constitute a withdrawal from pre-treatment roles. Current healthcare provision and statutory protections fail to fully meet needs following pelvic radiotherapy. IMPLICATIONS FOR CANCER SURVIVORS: There is a need to develop and implement evidence-based services and supported self-management programmes for survivors experiencing chronic bowel problems post-radiotherapy.

Modeling and control of anterior-posterior and medial-lateral sways in standing posture.

To study essential anterior-posterior and medial-lateral sways of the stance caused by rotational movements about the ankle and hip joints, a mathematical model is developed for the 3D postural kinematics and dynamics. The model is in the form of nonlinear differential-algebraic equations corresponding to a biomechanical system with holonomic constraints. A nonlinear feedback control law is further derived for stabilizing the upright stance, whilst eliminating internal torques induced by the constraints on postural movements. Numerical simulations of the model parametrized with experimental data of human body segments illustrate the performance of postural balancing with the proposed control.

"It's just inappropriate": Harassment of dental students by patients.

INTRODUCTION: Harassment is an issue that occurs in all workplaces and institutions. Due to increased exposure to patients, higher rates of harassment are experienced in health care systems. Health care workers need to form a professional relationship with patients to attend to their health care needs; however, harassment by patients can disrupt this relationship and have detrimental physical, mental, and emotional impacts on the health practitioner. OBJECTIVE: The purpose of this study was to examine the prevalence and impact of harassment by patients toward clinical students at a prominent Australasian dental school. METHODS: A 14-item survey was distributed to clinical students. The survey collected basic demographic information and contained Likert-scale closed questions on harassment prevalence and experience and a free text question asking for details of a significant harassment experience. Descriptive statistics and analysis of free text data were performed. RESULTS: The response rate was 67%. About 20% of respondents reported experiencing at least one incident of harassment. Verbal harassment was most commonly reported, followed by sexual and racial harassment. All incidences of sexual harassment were reported by female students, while racial harassment was most frequently reported by students of Asian ethnicity. Most students indicated they were unsure of how to respond to harassment by patients. CONCLUSION: Dental students were exposed to harassment by patients. IMPLICATIONS: Appropriate policies and education on responding to harassment, alongside support for the same, could help ensure the safety and wellbeing of students.

Validation of a morphometric reconstruction technique applied to a juvenile pelvis.

Three-dimensional reconstructions of bone geometry from microCT (computed tomography) data are frequently used in biomechanical and finite element analyses. Digitization of bone models is usually a simple process for specimens with a complete geometry, but in instances of damage or disarticulation it can be very challenging. Subsequent to digitization, further imaging techniques are often required to estimate the geometry of missing bone or connecting cartilage. This paper presents an innovative approach to the reconstruction of incomplete scan data, to reproduce proper anatomical arrangements of bones, including absent connecting cartilaginous elements. Utilizing geometric morphometric tools, the reconstruction technique is validated through comparison of a reconstructed 9 year old pelvis, to the original CT data. A principal component analysis and an overlay of the two pelves provide a measure of the accuracy of the reconstructed model. Future work aims to investigate the biomechanical effects of any minor positional error on the bone's predicted structural properties through the use of finite element analysis.

Detection of transient protein folding populations by mass spectrometry.

Hydrogen-deuterium exchange measurements are becoming increasingly important in studies of the dynamics of protein molecules and, particularly, of their folding behavior. Electrospray ionization mass spectrometry (ESI-MS) has been used to obtain the distribution of masses within a population of protein molecules that had undergone hydrogen exchange in solution. This information is complementary to that from nuclear magnetic resonance spectroscopy (NMR) experiments, which measure the average occupancy of individual sites over the distribution of protein molecules. In experiments with hen lysozyme, a combination of ESI-MS and NMR was used to distinguish between alternative mechanisms of hydrogen exchange, providing insight into the nature and populations of transient folding intermediates. These results have helped to detail the pathways available to a protein during refolding.

Protein folding monitored at individual residues during a two-dimensional NMR experiment.

An approach is described to monitor directly at the level of individual residues the formation of structure during protein folding. A two-dimensional heteronuclear nuclear magnetic resonance (NMR) spectrum was recorded after the rapid initiation of the refolding of a protein labeled with nitrogen-15. The intensities and line shapes of the cross peaks in the spectrum reflected the kinetic time course of the folding events that occurred during the spectral accumulation. The method was used to demonstrate the cooperative nature of the acquisition of the native main chain fold of apo bovine alpha-lactalbumin. The general approach, however, should be applicable to the investigation of a wide range of chemical reactions.

Masticatory loading and bone adaptation in the supraorbital torus of developing macaques.

Research on the evolution and adaptive significance of primate craniofacial morphologies has focused on adult, fully developed individuals. Here, we investigate the possible relationship between the local stress environment arising from masticatory loadings and the emergence of the supraorbital torus in the developing face of the crab-eating macaque Macaca fascicularis. By using finite element analysis (FEA), we are able to evaluate the hypothesis that strain energy density (SED) magnitudes are high in subadult individuals with resulting bone growth in the supraorbital torus. We developed three micro-CT-based FEA models of M. fascicularis skulls ranging in dental age from deciduous to permanent dentitions and validated them against published experimental data. Applied masticatory muscle forces were estimated from physiological cross-sectional areas of macaque cadaveric specimens. The models were sequentially constrained at each working side tooth to simulate the variation of the bite point applied during masticatory function. Custom FEA software was used to solve the voxel-based models and SED and principal strains were computed. A physiological superposition SED map throughout the face was created by allocating to each element the maximum SED value from each of the load cases. SED values were found to be low in the supraorbital torus region throughout ontogeny, while they were consistently high in the zygomatic arch and infraorbital region. Thus, if the supraorbital torus arises to resist masticatory loads, it is either already adapted in each of our subadult models so that we do not observe high SED or a lower site-specific bone deposition threshold must apply.

Sleeping beauty mutase (sbm) is expressed and interacts with ygfd in Escherichia coli.

In Escherichia coli, a four-gene operon, sbm-ygfD-ygfG-ygfH, has been shown to encode a putative cobalamin-dependent pathway with the ability to produce propionate from succinate in vitro [Haller T, Buckel T, Retey J, Gerlt JA. Discovering new enzymes and metabolic pathways: conversion of succinate to propionate by Escherichia coli. Biochemistry 2000;39:4622-4629]. However, the operon was thought to be silent in vivo, illustrated by the eponym describing its first gene, "sleeping beauty mutase" (methylmalonyl-CoA mutase, MCM). Of the four genes described, only ygfD could not be assigned a function. In this study, we have evaluated the functional integrity of YgfD and Sbm and show that, indeed, both proteins are expressed in E. coli and that YgfD has GTPase activity. We show that YgfD and Sbm can be co-immunoprecipitated from E. coli extracts using antibody to either protein, demonstrating in vivo interaction, a result confirmed using a strain deleted for ygfD. We show further that, in vitro, purified His-tagged YgfD and Sbm behave as a monomer and dimer, respectively, and that they form a multi-subunit complex that is dependent on pre-incubation of YgfD with non-hydrolysable GTP, an outcome that was not affected by the state of Sbm, as holo- or apoenzyme. These studies reinforce a role for the in vivo interaction of YgfD and Sbm.

Chemical form of dietary L-carnitine affects plasma but not tissue carnitine concentrations in male Sprague-Dawley rats.

In Experiment 1, rats (n = 54) were randomly assigned to control or one of the four sources of l-Carnitine supplemented at either 100 or 200 micromol/kg/day and were allowed to acclimate for 14 days. Following a 12-h fast, plasma samples were obtained at 0, 5, 10, 15, 30, 60, 120, 240, 480 and 720 min after l-Carnitine feeding and assayed for free l-Carnitine concentration. Plasma-free l-Carnitine levels were affected by time after treatment intake (p < 0.0001) and l-Carnitine source (p < 0.0001). The time x source interaction was not statistically significant (p = 0.99). In Experiment 2, rats (n = 54) were randomly assigned to control or one of the four sources of l-Carnitine at either 100 or 200 micromol/kg/day and were acclimated as in experiment 1. Rats were sacrificed 120 min after feeding. Samples of liver and skeletal muscle were obtained and assayed for free l-Carnitine concentration. Neither skeletal muscle (p = 0.44) or liver (p = 0.59) tissue concentrations of l-Carnitine were affected by any l-Carnitine source as compared with the control. We conclude that some differences exist in plasma concentrations of free l-Carnitine following ingestion of different chemical forms of l-Carnitine. It is unclear if these differences in the circulating concentration of free l-Carnitine translate into any physiological differences for the animal. In this study, chemical form of l-Carnitine had no effect on skeletal muscle or liver tissue concentrations of l-Carnitine in young male Wistar rats.

Understanding how proteins fold: the lysozyme story so far.

Hen lysozyme is one of the best characterized and most studied of all proteins. Recently, we have used a range of different methods to examine the events involved in the in vitro folding pathway of this protein. In this review we show that, by combining complementary techniques, it has been possible to piece together a detailed model for the folding of this enzyme. Important questions prompted by this work are highlighted and we then propose some ideas consistent with our data, as well as those of others, which we believe begin to provide insight into one of the most intriguing of structural problems in biology--how proteins can achieve their complex native forms from disordered denatured states.

Understanding protein folding via free-energy surfaces from theory and experiment.

The ability of protein molecules to fold into their highly structured functional states is one of the most remarkable evolutionary achievements of biology. In recent years, our understanding of the way in which this complex self-assembly process takes place has increased dramatically. Much of the reason for this advance has been the development of energy surfaces (landscapes), which allow the folding reaction to be described and visualized in a meaningful manner. Analysis of these surfaces, derived from the constructive interplay between theory and experiment, has led to the development of a unified mechanism for folding and a recognition of the underlying factors that control the rates and products of the folding process.

The mechanical loading and muscle activation of four common exercises used in osteoporosis prevention for early postmenopausal women.

High impact exercise can reduce postmenopausal bone loss, however stimulus frequency (loading cycles per second) can affect osteogenesis. We aimed to examine the effect of stimulus frequency on the mechanical loading of four common osteoporosis prevention exercises, measuring body acceleration and muscle activation with accelerometry and electromyography (EMG), respectively. Fourteen early postmenopausal women completed randomised countermovement jumps (CMJ), box-drops (BD), heel-drops (HD) and stamp (STP) exercises for continuous and intermittent stimulus frequencies. Sacrum accelerometry and surface electromyography (EMG) of four muscles were recorded. CMJ (mean ±â€¯SD: 10.7 ±â€¯4.8 g & 10.0 ±â€¯5.0 g), BD (9.6 ±â€¯4.1 g & 9.5 ±â€¯4.0 g) and HD (7.3 ±â€¯3.8 g & 8.6 ±â€¯4.4 g) conditions generated greater peak acceleration than STP (3.5 ±â€¯1.4 g & 3.6 ±â€¯1.7 g) across continuous and intermittent trials. CMJ and BD generated greater acceleration gradients than STP across continuous and intermittent trials. CMJ generated greater rectus femoris EMG than all other exercises, CMJ and BD generated greater semitendinosus and tibialis anterior EMG than HD across continuous and intermittent trials. CMJ and BD provide greater peak acceleration than STP and remain similar during different stimulus frequencies. CMJ, BD and HD may exceed STP in maintaining postmenopausal bone health.

Real-time PCR detection of bacteria belonging to the Firmicutes Phylum.

Members of the bacterial Phylum Firmicutes occupy a wide range of habitats and can be either beneficial or detrimental in diverse settings, including food- and beverage-related industries. Firmicutes are responsible for the vast majority of beer-spoilage incidents and, as such, they have a substantial financial impact in the brewing industry. Rapid detection and identification of a bacterium as a Firmicutes is difficult due to widespread genetic transfer and genome reduction resulting in phenotypic diversity in these bacteria. Here we describe a real-time multiplex PCR to detect and differentiate Firmicutes associated with beer-spoilage from non-Firmicutes bacteria that may be present as benign environmental contaminants. A region of the 16S rRNA gene was identified and predicted to be highly conserved amongst, and essentially specific for, Firmicutes. A real-time PCR assay using a hydrolysis probe targeting this region of the 16S rRNA gene was experimentally shown to detect ten genera of Firmicutes known to be beer spoilers, but does not cross-react with eleven of twelve non-Firmicutes genera which can periodically appear in beer. Only one non-Firmicutes species, Zymomonas mobilis, weakly reacted with the Firmicutes probe. This rPCR assay has a standard curve that is linear over six orders of magnitude of DNA, with a quantitation limit of DNA from <10 bacteria. When used to detect bacteria present in beer, the assay was able to detect 50-100 colony forming units (CFU) of Firmicutes directly from 2.5 cm membranes used to filter 100 ml of contaminated beer. Through incorporation of a 4.7 cm filter and an overnight pre-enrichment incubation, the sensitivity was increased to 2.5-10 CFU per package of beer (341 ml). When multiplexed with a second hydrolysis probe targeting a universal region of the 16S rRNA gene, the assay reliably differentiates between Firmicutes and non-Firmicutes bacteria found in breweries.

New insights into the biomechanics of Legg-Calvé-Perthes' disease: The Role of Epiphyseal Skeletal Immaturity in Vascular Obstruction.

OBJECTIVES: Legg-Calvé-Perthes' disease (LCP) is an idiopathic osteonecrosis of the femoral head that is most common in children between four and eight years old. The factors that lead to the onset of LCP are still unclear; however, it is believed that interruption of the blood supply to the developing epiphysis is an important factor in the development of the condition. METHODS: Finite element analysis modelling of the blood supply to the juvenile epiphysis was investigated to understand under which circumstances the blood vessels supplying the femoral epiphysis could become obstructed. The identification of these conditions is likely to be important in understanding the biomechanics of LCP. RESULTS: The results support the hypothesis that vascular obstruction to the epiphysis may arise when there is delayed ossification and when articular cartilage has reduced stiffness under compression. CONCLUSION: The findings support the theory of vascular occlusion as being important in the pathophysiology of Perthes disease.Cite this article: M. Pinheiro, C. A. Dobson, D. Perry, M. J. Fagan. New insights into the biomechanics of Legg-Calvé-Perthes' disease: The Role of Epiphyseal Skeletal Immaturity in Vascular Obstruction. Bone Joint Res 2018;7:148-156. DOI: 10.1302/2046-3758.72.BJR-2017-0191.R1.

Protein folding. Solid evidence for molten globules.

Novel experimental strategies are providing details of the structures of non-native states of proteins and shedding light on the concept of a "molten globule" and its relevance to protein folding.