Movement kinematic and postural control differences when performing a visuomotor skill in real and virtual environments.

Immersive technologies, like virtual and mixed reality, pose a novel challenge for our sensorimotor systems as they deliver simulated sensory inputs that may not match those of the natural environment. These include reduced fields of view, missing or inaccurate haptic information, and distortions of 3D space; differences that may impact the control of motor actions. For instance, reach-to-grasp movements without end-point haptic feedback are characterised by slower and more exaggerated movements. A general uncertainty about sensory input may also induce a more conscious form of movement control. We tested whether a more complex skill like golf putting was also characterized by more consciously controlled movement. In a repeated-measures design, kinematics of the putter swing and postural control were compared between (i) real-world putting, (ii) VR putting, and (iii) VR putting with haptic feedback from a real ball (i.e., mixed reality). Differences in putter swing were observed both between the real world and VR, and between VR conditions with and without haptic information. Further, clear differences in postural control emerged between real and virtual putting, with both VR conditions characterised by larger postural movements, which were more regular and less complex, suggesting a more conscious form of balance control. Conversely, participants actually reported less conscious awareness of their movements in VR. These findings highlight how fundamental movement differences may exist between virtual and natural environments, which may pose challenges for transfer of learning within applications to motor rehabilitation and sport.

Finding gaps in routine TB surveillance activities in Bangladesh.

BACKGROUND: TB was the leading cause of death from a single infectious pathogen globally between 2014 and 2019. Fine-scale estimates of TB prevalence and case notifications can be combined to guide priority-setting for strengthening routine surveillance activities in high-burden countries. We produce policy-relevant estimates of the TB epidemic at the second administrative unit in Bangladesh.METHODS: We used a Bayesian spatial framework and the cross-sectional National TB Prevalence Survey from 2015-2016 in Bangladesh to estimate prevalence by district. We used case notifications to calculate prevalence-to-notification ratio, a key metric of under-diagnosis and under-reporting.RESULTS: TB prevalence rates were highest in the north-eastern districts and ranged from 160 cases per 100,000 (95% uncertainty interval [UI] 80-310) in Jashore to 840 (UI 690-1020) in Sunamganj. Despite moderate prevalence rates, the Rajshahi and Dhaka Divisions presented the highest prevalence-to-notification ratios due to low case notifications. Resolving subnational disparities in case detection could lead to 26,500 additional TB cases (UI 8,500-79,400) notified every year.CONCLUSION: This study is the first to produce and map subnational estimates of TB prevalence and prevalence-to-notification ratios, which are essential to target prevention and treatment efforts in high-burden settings. Reaching TB cases currently missing from care will be key to ending the TB epidemic.

The discrimination of geoforensic trace material from close proximity locations by organic profiling using HPLC and plant wax marker analysis by GC.

There is a need to develop a wider empirical research base to expand the scope for utilising the organic fraction of soil in forensic geoscience, and to demonstrate the capability of the analytical techniques used in forensic geoscience to discriminate samples at close proximity locations. The determination of wax markers from soil samples by GC analysis has been used extensively in court and is known to be effective in discriminating samples from different land use types. A new HPLC method for the analysis of the organic fraction of forensic sediment samples has also been shown recently to add value in conjunction with existing inorganic techniques for the discrimination of samples derived from close proximity locations. This study compares the ability of these two organic techniques to discriminate samples derived from close proximity locations and finds the GC technique to provide good discrimination at this scale, providing quantification of known compounds, whilst the HPLC technique offered a shorter and simpler sample preparation method and provided very good discrimination between groups of samples of different provenance in most cases. The use of both data sets together gave further improved accuracy rates in some cases, suggesting that a combined organic approach can provide added benefits in certain case scenarios and crime reconstruction contexts.

Auditory white noise reduces age-related fluctuations in balance.

Fall prevention technologies have the potential to improve the lives of older adults. Because of the multisensory nature of human balance control, sensory therapies, including some involving tactile and auditory noise, are being explored that might reduce increased balance variability due to typical age-related sensory declines. Auditory white noise has previously been shown to reduce postural sway variability in healthy young adults. In the present experiment, we examined this treatment in young adults and typically aging older adults. We measured postural sway of healthy young adults and adults over the age of 65 years during silence and auditory white noise, with and without vision. Our results show reduced postural sway variability in young and older adults with auditory noise, even in the absence of vision. We show that vision and noise can reduce sway variability for both feedback-based and exploratory balance processes. In addition, we show changes with auditory noise in nonlinear patterns of sway in older adults that reflect what is more typical of young adults, and these changes did not interfere with the typical random walk behavior of sway. Our results suggest that auditory noise might be valuable for therapeutic and rehabilitative purposes in older adults with typical age-related balance variability.

Cytokine profiles in women with different subtypes of major depressive disorder.

BACKGROUND: Depression has been associated with activation of the immune system. Some studies have shown increased levels of pro-inflammatory cytokines in patients with major depressive disorder (MDD), but conflicting results also have been described. METHODS: Forty-six unmedicated women with MDD were classified in subgroups (melancholic vs. non-melancholic; acute vs. chronic; severe vs. moderate, and episodic vs. recurrent presentations) and compared with 41 healthy controls. Evaluations of serum IL-1beta, IL-6, IFN-gamma and cortisol were performed on both groups. Patients were evaluated prior and after antidepressant treatment. RESULTS: The sub-classification of depression did not predict differences in cytokine levels. Patients currently depressed had similar levels of cytokines and cortisol as healthy controls. After remission of the symptoms, patients with MDD evolved with enhancement of cytokine levels, but no differences were observed in cortisol levels. LIMITATIONS: In patient treatment, two different classes of antidepressants were applied. The dexamethasone/CRH test was not performed to evaluate the HPA axis. CONCLUSIONS: Out-patient women diagnosed with MDD exhibited normal levels of both cortisol and cytokines before treatment, yet demonstrated an increase in cytokines after antidepressant treatment. In some patients with MDD, the presence of acute stress due to hospitalization may indeed contribute and justify the usual finding of higher levels in both cortisol and cytokines.

In vitro culture of enzymatically isolated chondrons: a possible model for the initiation of osteoarthritis.

The aim of this study was to assess whether enzymatically isolated chondrons from normal adult articular cartilage could be used as a model for the onset of osteoarthritis, by comparison with mechanically extracted chondrons from osteoarthritic cartilage. Enzymatically isolated chondrons (EC) were cultured for 4 weeks in alginate beads and agarose gel constructs. Samples were collected at days 1 and 2, and weekly thereafter. Samples were immunolabelled for types II and VI collagen, keratan sulphate and fibronectin and imaged using confocal microscopy. Mechanically extracted chondrons (MC) were isolated, immunohistochemically stained for type VI collagen and examined by confocal microscopy. In culture, EC showed the following characteristics: swelling of the chondron capsule, cell division within the capsule and remodelling of the pericellular microenvironment. This was followed by chondrocyte migration through gaps in the chondron capsule. Four types of cell clusters formed over time in both alginate beads and agarose constructs. Cells within clusters exhibited quite distinct morphologies and also differed in their patterns of matrix deposition. These differences in behaviour may be due to the origin of the chondrocytes in the intact tissue. The behaviour of EC in culture paralleled the range of morphologies observed in MC, which presented as single and double chondrons and large chondron clusters. This preliminary study indicates that EC in culture share similar structural characteristics with MC isolated from osteoarthritic cartilage, confirming that some processes that occur in osteoarthritis, such as pericellular remodelling, take place in EC cultures. The study of EC in culture may therefore provide an additional tool to investigate the mechanisms operating during the initial stages of osteoarthritis. Further investigation of specific osteoarthritic phenotype markers will, however, be required in order to validate the value of this model.

Immunohistochemical demonstration of leptin in pancreatic islets of non-obese diabetic and CD-1 mice: co-localization in glucagon cells and its attenuation at the onset of diabetes.

Leptin is a 16 kD polypeptide hormone produced predominantly by white adipose tissue and exerts profound effects on food intake and energy balance. More recent studies have shown extra sites of leptin production in human and rodent tissues and have ascribed additional roles for the hormone, e.g., in immune and reproductive functions. A role for the hormone has also been implicated in insulin-dependent diabetes mellitus in the non-obese diabetic (NOD) mouse. However, whether leptin originates from islet cells of the mouse is not known. Here dual-label immunohistochemistry was employed to examine leptin expression in islet cells, and its distribution and cellular sources in pancreatic sections of female NOD/Ak and CD-1 mice of various ages. For comparison, leptin immunolabelling was examined in adult pancreatic sections from male NOD/Ak CD-1, Balb/c and FVB/N mice and female severe combined immunodeficient CB. 17 mice. Pancreatic tissues from adult female guinea pig, sheep and cattle and neonatal pigs were also studied. Our results show that in the day 1 NOD and CD-1 mice, leptin immunolabelling was observed in selective glucagon cells within the developing islets while at days 15 and 22, it became more intense and co-incident. This pattern of staining was maintained at days 40, 90, 150 and 250. In the female NOD mouse, leptin was absent in intra-islet immune cells. Its expression was variable in islets from male NOD and CD-1 mice. In spontaneously diabetic female NOD mice and following acceleration of diabetes with cyclophosphamide, despite the persistence of strong immunolabelling for glucagon in the re-distributed alpha cells, leptin expression was either absent, diminished or present in only a proportion of alpha cells. The reduction in leptin labelling was often associated with diabetic islets which had insulitis in association with only a small number of residual beta cells. Leptin expression was absent in guinea pig, ovine, bovine and neonatal porcine islet cells, despite the expression of intensely labelled glucagon cells. The present results demonstrate leptin co-localization in glucagon cells of the mouse islet. Its expression diminishes in the presence of inadequate insulin. Leptin produced within the mouse islet may have bi-directional influences on leptin and insulin regulation and may play local functions in islet development and metabolism.

Fas and Fas ligand immunolocalization in pancreatic islets of NOD mice during spontaneous and cyclophosphamide-accelerated diabetes.

During insulin-dependent diabetes mellitus, immune cells which infiltrate pancreatic islets mediate beta cell destruction over a prolonged asymptomatic prediabetic period. The molecular mechanisms of beta cell death in vivo remain unresolved. At least two major molecular processes of destruction have been proposed. One involves the Fas-FasL (Fas-Fas ligand) system and the other, the perforin pathway. Here, dual-label immunohistochemistry was employed to examine the intra-islet expression, distribution and cellular sources of Fas and FasL in the NOD mouse, during spontaneous diabetes (days 21, 40 and 90) and following acceleration of diabetes with cyclophosphamide (days 0, 4, 7, 11 and 14 after cyclophosphamide administration). The expression of the proteins was correlated with advancing disease. FasL was expressed constitutively in most beta cells but not in glucagon or somatostatin cells or islet inflammatory cells and paralleled the loss of insulin immunolabelling with advancing disease. It was also expressed in beta cells of non-diabetes prone CD-1 and C57BL/6 mice from a young age (day 21). Strong immunolabelling for Fas was first observed in extra-islet macrophages and those close to the islet in NOD and non-diabetes-prone mice. During spontaneous and cyclophosphamide diabetes, it was observed in a higher proportion of islet infiltrating macrophages than CD4 and CD8 T cells, concomitant with advancing insulitis. In cyclophosphamide-treated mice, the proportion of Fas-positive intra-islet CD4 and CD8 T cells at day 14 (with and without diabetes) was considerably higher than at days 0, 4, 7 and 11. At days 11 and 14, a proportion of Fas-positive intra-islet macrophages co-expressed interleukin-1beta and inducible nitric oxide synthase. Fas was not detectable in beta cells and other islet endocrine cells during spontaneous and cyclophosphamide induced diabetes. Our results show constitutive expression of FasL in beta cells in the NOD mouse and predominant expression of Fas in intra-islet macrophages and to a lesser extent in T cells prior to diabetes onset. Interleukin-1beta in intra-islet macrophages may induce Fas and inducible nitric oxide synthase expression in an autocrine and paracrine manner and mediate beta cell destruction or even death of some macrophages and T cells. However, other mechanisms of beta cell destruction during spontaneous and cyclophosphamide-accelerated diabetes and independent of Fas-FasL, require examination.

The differential distribution of acetylated and detyrosinated alpha-tubulin in the microtubular cytoskeleton and primary cilia of hyaline cartilage chondrocytes.

The primary cilium is a ubiquitous cytoplasmic organelle of unknown function. Ultrastructural evidence of primary cilia in chondrocytes, and their colocalisation with the Golgi apparatus, has led to speculation that these structures are functionally linked. To investigate the relationship between these organelles, we examined the molecular anatomy of the microtubular cytoskeleton in the chondrocytes of chick embryo sterna. Thick cryosections were immunolabelled with antibodies directed against acetylated alpha-tubulin (C3B9), detyrosinated alpha-tubulin (ID5) and total alpha-tubulin (TAT), and imaged at high magnification using confocal laser scanning microscopy. Transmission electron microscopy confirmed the ultrastructure of the chondrocyte primary cilium and its structural relationship to the Golgi apparatus. Detyrosinated and acetylated alpha-tubulins were concentrated in the centrioles, centrosome and microtubule organising centre adjacent to the nucleus, with total alpha-tubulin distributed throughout the cytoplasm. ID5 stained the primary cilium at an incidence of 1 per cell, its colocalisation with C3B9 identifying the primary cilium as one of the most stable features of the microtubular cytoskeleton. Primary cilia varied from 1 to 4 microm in length, and 3 patterns of projection into the extracellular matrix were identified; (1) full extension and matrix contact, with minor undulations along the length; (2) partial extension and matrix contact, with a range of bending deflections; (3) cilium reclined against the cell surface with minimal matrix contact. Ultrastructural studies identified direct connections between extracellular collagen fibres and the proteins which decorate ciliary microtubules, suggesting a matrix-cilium-Golgi continuum in hyaline chondrocytes. These results strengthen the hypothesis that the primary cilium acts as a 'cellular cybernetic probe' capable of transducing environmental information from the extracellular matrix, communicating this information to the centrosome. and regulating the exocytosis of Golgi-derived secretory vesicles.

Shear stress prevents fibronectin binding protein-mediated Staphylococcus aureus adhesion to resting endothelial cells.

Fibronectin binding proteins (FnBP) on the surface of Staphylococcus aureus have previously been shown to mediate adherence of the organism to resting endothelial cells in static adhesion assays. However, in this study using well-defined flow assays, we demonstrate that physiologic levels of shear stress prevent FnBP-mediated adhesion of S. aureus 8325-4 to resting endothelial cells. This result suggests that mechanical forces present in vivo may influence the ability of staphylococci to bind endothelial cell surfaces.

Chondrocyte deformation within mechanically and enzymatically extracted chondrons compressed in agarose.

Within articular cartilage, the chondron microenvironment will influence chondrocyte behaviour and response to loading. Chondrons were extracted from intact cartilage using either mechanical homogenisation (MC) or enzymatic digestion (EC) and cell and matrix morphology in unstrained and compressed agarose constructs was examined. Isolated chondrocytes (IC) were used for comparison. Immunolocalisation of type VI collagen and keratan sulphate revealed differences in the structure of the pericellular microenvironment such that MC most closely resembled chondrons in situ. The unstrained cell diameters of IC and EC were larger than MC at day 1 and increased significantly over a 7 day culture period. In contrast, cell diameters for MC remained constant. Compression of constructs at day 1 resulted in cell deformation for IC and EC but not MC. The two chondron extraction methods yielded chondrons of differing matrix morphology and associated differences in cell size and cellular response to load. The results indicate that the pericellular microenvironment of MC initially possessed a greater mechanical integrity than that of EC. Although these differences may be reduced with time in culture, characterisation of mechanically isolated chondrons suggests that the stiffness of the chondrons in situ may be greater than previous estimates.

Hydrodynamic shear and collagen receptor density determine the adhesion capacity of S. aureus to collagen.

Dynamic bacterial adhesion has recently gained significant attention due to its role in the initiation of infectious diseases. Staphylococcus aureus binding to collagen has been shown to be an important event in the pathogenesis of infection. Staphylococcal strains have exhibited wide variability in their level of collagen binding, which may be a result of the collagen receptor expression level. In this study, the dynamic adhesion to collagen for several S. aureus strains was quantified at physiological wall shear rates in a parallel-plate flow chamber. In addition, the collagen receptor density was quantified for each strain. An existing theoretical framework was used to analyze the dependence of adhesion on receptor density. Intrinsic kinetic adhesion parameters were determined and demonstrated to be strong functions of receptor density for all strains. These results suggest that staphylococcal adhesion to collagen is heavily dependent on the receptor density. Using this analytical approach it is possible to predict the dynamic adhesion of S. aureus to collagen in vitro by only measuring the collagen receptor density.

Shear stress affects the kinetics of Staphylococcus aureus adhesion to collagen.

Staphylococcus aureus is a major human pathogen that has been shown to bind collagen under static conditions. However, many staphylococcal infections are hematogenously acquired and adhesion events may be influenced by shear stress. In this study, we used a dynamic experimental system consisting of a parallel-plate perfusion chamber and phase-contrast video microscope to study the effects of shear stress on the adhesion kinetics of intact S. aureus to collagen surfaces in vitro. The adhesion of S. aureus Phillips to collagen types I, II, and IV was investigated over a physiologically relevant range of wall shear stresses at 37 degrees C. S. aureus PH100, a collagen adhesin-deficient mutant strain, was used as a control strain for the experiments. We found that S. aureus Phillips could adhere to collagens I, II, and IV at wall shear stresses less than 15 dyn/cm(2) and that the kinetics of the adhesion process were wall shear stress-dependent. Similar studies with PH100 demonstrated that these cells are unable to adhere firmly to collagen surfaces. Transient interactions between PH100 and the collagen surfaces were observed at low levels of shear stress suggesting that S. aureus may also interact with collagen by an alternative mechanism that does not lead to firm adhesion.

Dual-label immunohistochemical study of interleukin-4-and interferon-gamma-expressing cells within the pancreas of the NOD mouse during disease acceleration with cyclophosphamide.

Beta cell destruction has been shown to occur when rodent or human islets are exposed in vitro to inflammatory cytokines, such as interleukin-1beta (IL-1beta), tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma). Other cytokines such as interleukin-4 (IL-4) or interleukin-10 (IL-10), when given to NOD mice, prevent insulin-dependent diabetes mellitus (IDDM). In this study, we have employed immunofluorescence histochemistry to study the expression of IFN-gamma and IL-4 in the pancreas of female NOD mice at various time-points (days 0, 4, 7, 11 and at onset of diabetes) following disease acceleration with cyclophosphamide (Cy). Dual-label confocal and light microscopy were employed to determine the precise cellular sources of the two cytokines. IL-4 immunolabelling was observed in a few immune cells at days 0, 4, and 7 within the pancreatic islets but in larger numbers at day 11 and at onset of diabetes. The cytokine was co-localized predominantly in CD4 cells, while only a small minority of CD8 cells and macrophages also expressed IL-4. At days 0, 4, 7 and 11, weak to moderate immunolabelling for IL-4 was also observed in beta cells. In contrast, immunolabelling for IFN-gamma within the islets was not observed until day 11 and this labelling persisted at onset of diabetes. It was immunolocalized in macrophages and to a lesser extent in CD4 cells. Only a few CD8 cells were immunopositive for IFN-gamma. At day 11, a proportion of beta cells showed weak immunolabelling for IFN-gamma. During the study period, immunolabelling for IFN-gamma was also observed in a proportion of endothelial cells located in the intra-islet and exocrine regions of Cy and diluent-treated mice. From day 11 onwards, both the cytokines were observed in some of the peri-vascular regions. Our results demonstrate that during Cy-induced diabetes, there is increasing expression of both IL-4 and IFN-gamma in specific immune cells within the inflamed islets in the late prediabetic stage and at onset of diabetes. Further studies are required to correlate our protein immunohistochemical findings with in situ cytokine gene expression and to determine whether there is a clear Th1 cytokine protein bias at clinical onset of diabetes and immediately preceding it.

Quantification of Staphylococcus aureus cell surface adhesins using flow cytometry.

The initiation of many infectious diseases involves specific adhesion of bacteria to host tissue proteins and carbohydrates. Staphylococcus aureus is known to bind specifically to several proteins in the extracellular matrix (ECM). We report the quantification of the collagen and fibronectin adhesin densities on the staphylococcal surface using flow cytometry. Our results are in agreement with previous reports on the transcription of the respective genes and demonstrate different patterns of temporal expression for the two adhesins in the strains studied. We demonstrate a convenient technique for quantification of bacterial adhesins that can be used in studies aimed at characterization of bacterial adhesion to ECM components and understanding expression of adhesins during the course of an infection.

Mab-3 is a direct tra-1 target gene regulating diverse aspects of C. elegans male sexual development and behavior.

Sex determination is controlled by global regulatory genes, such as tra-1 in Caenorhabditis elegans, Sex lethal in Drosophila, or Sry in mammals. How these genes coordinate sexual differentiation throughout the body is a key unanswered question. tra-1 encodes a zinc finger transcription factor, TRA-1A, that regulates, directly or indirectly, all genes required for sexual development. mab-3 (male abnormal 3), acts downstream of tra-1 and is known to be required for sexual differentiation of at least two tissues. mab-3 directly regulates yolk protein transcription in the intestine and specifies male sense organ differentiation in the nervous system. It encodes a transcription factor related to the products of the Drosophila sexual regulator doublesex (dsx), which also regulates yolk protein transcription and male sense-organ differentiation. The similarities between mab-3 and dsx led us to suggest that some aspects of sex determination may be evolutionarily conserved. Here we find that mab-3 is also required for expression of male-specific genes in sensory neurons of the head and tail and for male interaction with hermaphrodites. These roles in male development and behavior suggest further functional similarity to dsx. In male sensory ray differentiation we find that MAB-3 acts synergistically with LIN-32, a neurogenic bHLH transcription factor. Expression of LIN-32 is spatially restricted by the combined action of the Hox gene mab-5 and the hairy homolog lin-22, while MAB-3 is expressed throughout the lateral hypodermis. Finally, we find that mab-3 transcription is directly regulated in the intestine by TRA-1A, providing a molecular link between the global regulatory pathway and terminal sexual differentiation.

Temporal relationship between immune cell influx and the expression of inducible nitric oxide synthase, interleukin-4 and interferon-gamma in pancreatic islets of NOD mice following adoptive transfer of diabetic spleen cells.

Beta cell destruction in NOD mice can be accelerated by adoptive transfer of diabetic spleen cells into irradiated adult NOD mice. Here mice receiving diabetic spleen cells were examined at days 0, 7, 14, 21 and at onset of diabetes for the resulting insulitis and the number of intra-islet CD4 and CD8 cells and macrophages. The progression of insulitis and the number of intra-islet CD4 and CD8 cells and macrophages were correlated with the expression and co-localization of inducible nitric oxide synthase, interferon-gamma and interleukin-4 by dual-label light and confocal immunofluorescence microscopy. Diabetes developed in 7/8 mice by 27 days following cell transfer. The insulitis score increased slightly by day 7 but rose sharply at day 14 (p = 0.001) and was maintained until diabetes. The mean number of intra-islet CD4 and CD8 cells and macrophages showed a similar trend to the insulitis scores and were present in almost equal numbers within the islets. Immunolabelling for inducible nitric oxide synthase was observed at day 7 in only some cells of a few islets but increased sharply from day 14. It was restricted to islets with insulitis and was co-localized in selective macrophages. Weak intra-islet interleukin-4 labelling was observed at days 7 and 14 but became more pronounced at day 21 and at onset of diabetes, being present in selective CD4 cells. Intra-islet labelling for interferon-gamma was first observed at day 21, but became more intense at onset of diabetes and was co-localized in a proportion of macrophages. Both cytokines were expressed in islets with advanced insulitis. Interferon-gamma staining was also observed within endothelial cells located in the exocrine pancreas. We conclude that transfer of diabetic spleen cells results in a rapid influx of CD4 and CD8 cells and macrophages within the pancreas of recipient mice. During the period of heightened insulitis, selective immune cells begin to express inducible nitric oxide synthase and the opposing cytokines, interferon-gamma and interleukin-4. Expression of these molecules becomes more pronounced immediately prior to and during the onset of diabetes.