Calcium Signalling Triggered by NAADP in T Cells Determines Cell Shape and Motility During Immune Synapse Formation

Nicotinic acid adenine dinucleotide phosphate (NAADP) has been implicated as an initial Ca(2+) trigger in T cell Ca(2+) signalling, but its role in formation of the immune synapse in CD4(+) effector T cells has not been analysed. CD4(+) T cells are activated by the interaction with peptide-MHCII complexes on the surface of antigen-presenting cells. Establishing a two-cell system including primary rat CD4(+) T cells specific for myelin basic protein and rat astrocytes enabled us to mirror this activation process in vitro and to analyse Ca(2+) signalling, cell shape changes and motility in T cells during formation and maintenance of the immune synapse. After immune synapse formation, T cells showed strong, antigen-dependent increases in free cytosolic calcium concentration ([Ca(2+)](i)). Analysis of cell shape and motility revealed rounding and immobilization of T cells depending on the amplitude of the Ca(2+) signal. NAADP-antagonist BZ194 effectively blocked Ca(2+) signals in T cells evoked by the interaction with antigen-presenting astrocytes. BZ194 reduced the percentage of T cells showing high Ca(2+) signals thereby supporting the proposed trigger function of NAADP for global Ca(2+) signalling. Taken together, the NAADP signalling pathway is further confirmed as a promising target for specific pharmacological intervention to modulate T cell activation

A reconfigurable real-time compressive-sampling camera for biological applications

Many applications in biology, such as long-term functional imaging of neural and cardiac systems, require continuous high-speed imaging. This is typically not possible, however, using commercially available systems. The frame rate and the recording time of high-speed cameras are limited by the digitization rate and the capacity of on-camera memory. Further restrictions are often imposed by the limited bandwidth of the data link to the host computer. Even if the system bandwidth is not a limiting factor, continuous high-speed acquisition results in very large volumes of data that are difficult to handle, particularly when real-time analysis is required. In response to this issue many cameras allow a predetermined, rectangular region of interest (ROI) to be sampled, however this approach lacks flexibility and is blind to the image region outside of the ROI. We have addressed this problem by building a camera system using a randomly-addressable CMOS sensor. The camera has a low bandwidth, but is able to capture continuous high-speed images of an arbitrarily defined ROI, using most of the available bandwidth, while simultaneously acquiring low-speed, full frame images using the remaining bandwidth. In addition, the camera is able to use the full-frame information to recalculate the positions of targets and update the high-speed ROIs without interrupting acquisition. In this way the camera is capable of imaging moving targets at high-speed while simultaneously imaging the whole frame at a lower speed. We have used this camera system to monitor the heartbeat and blood cell flow of a water flea (Daphnia) at frame rates in excess of 1500 fps

New genetic loci implicated in fasting glucose homeostasis and their impact on type 2 diabetes risk.

Levels of circulating glucose are tightly regulated. To identify new loci influencing glycemic traits, we performed meta-analyses of 21 genome-wide association studies informative for fasting glucose, fasting insulin and indices of beta-cell function (HOMA-B) and insulin resistance (HOMA-IR) in up to 46,186 nondiabetic participants. Follow-up of 25 loci in up to 76,558 additional subjects identified 16 loci associated with fasting glucose and HOMA-B and two loci associated with fasting insulin and HOMA-IR. These include nine loci newly associated with fasting glucose (in or near ADCY5, MADD, ADRA2A, CRY2, FADS1, GLIS3, SLC2A2, PROX1 and C2CD4B) and one influencing fasting insulin and HOMA-IR (near IGF1). We also demonstrated association of ADCY5, PROX1, GCK, GCKR and DGKB-TMEM195 with type 2 diabetes. Within these loci, likely biological candidate genes influence signal transduction, cell proliferation, development, glucose-sensing and circadian regulation. Our results demonstrate that genetic studies of glycemic traits can identify type 2 diabetes risk loci, as well as loci containing gene variants that are associated with a modest elevation in glucose levels but are not associated with overt diabetes

Characteristics of undernourished older medical patients and the identification of predictors for undernutrition status

<p>Abstract</p> <p>Background</p> <p>Undernutrition among older people is a continuing source of concern, particularly among acutely hospitalized patients. The purpose of the current study is to compare malnourished elderly patients with those at nutritional risk and identify factors contributing to the variability between the groups.</p> <p>Methods</p> <p>The study was carried out at the Soroka University Medical Center in the south of Israel. From September 2003 through December 2004, all patients 65 years-of-age or older admitted to any of the internal medicine departments, were screened within 72 hours of admission to determine nutritional status using the short version of the Mini Nutritional Assessment (MNA-SF). Patients at nutritional risk were entered the study and were divided into malnourished or 'at risk' based on the full version of the MNA. Data regarding medical, nutritional, functional, and emotional status were obtained by trained interviewers.</p> <p>Results</p> <p>Two hundred fifty-nine elderly patients, 43.6% men, participated in the study; 18.5% were identified as malnourished and 81.5% were at risk for malnutrition according to the MNA. The malnourished group was less educated, had a higher depression score and lower cognitive and physical functioning. Higher prevalence of chewing problems, nausea, and vomiting was detected among malnourished patients. There was no difference between the groups in health status indicators except for subjective health evaluation which was poorer among the malnourished group. Lower dietary score indicating lower intake of vegetables fruits and fluid, poor appetite and difficulties in eating distinguished between malnourished and at-risk populations with the highest sensitivity and specificity as compare with the anthropometric, global, and self-assessment of nutritional status parts of the MNA. In a multivariate analysis, lower cognitive function, education <12 years and chewing problems were all risk factors for malnutrition.</p> <p>Conclusion</p> <p>Our study indicates that low food consumption as well as poor appetite and chewing problems are associated with the development of malnutrition. Given the critical importance of nutritional status in the hospitalized elderly, further intervention trials are required to determine the best intervention strategies to overcome these problems.</p

Nicotinic acid adenine dinucleotide phosphate-mediated calcium signalling in effector T cells regulates autoimmunity of the central nervous system

Nicotinic acid adenine dinucleotide phosphate represents a newly identified second messenger in T cells involved in antigen receptor-mediated calcium signalling. Its function in vivo is, however, unknown due to the lack of biocompatible inhibitors. Using a recently developed inhibitor, we explored the role of nicotinic acid adenine dinucleotide phosphate in autoreactive effector T cells during experimental autoimmune encephalomyelitis, the animal model for multiple sclerosis. We provide in vitro and in vivo evidence that calcium signalling controlled by nicotinic acid adenine dinucleotide phosphate is relevant for the pathogenic potential of autoimmune effector T cells. Live two photon imaging and molecular analyses revealed that nicotinic acid adenine dinucleotide phosphate signalling regulates T cell motility and re-activation upon arrival in the nervous tissues. Treatment with the nicotinic acid adenine dinucleotide phosphate inhibitor significantly reduced both the number of stable arrests of effector T cells and their invasive capacity. The levels of pro-inflammatory cytokines interferon-gamma and interleukin-17 were strongly diminished. Consecutively, the clinical symptoms of experimental autoimmune encephalomyelitis were ameliorated. In vitro, antigen-triggered T cell proliferation and cytokine production were evenly suppressed. These inhibitory effects were reversible: after wash-out of the nicotinic acid adenine dinucleotide phosphate antagonist, the effector T cells fully regained their functions. The nicotinic acid derivative BZ194 induced this transient state of non-responsiveness specifically in post-activated effector T cells. Naïve and long-lived memory T cells, which express lower levels of the putative nicotinic acid adenine dinucleotide phosphate receptor, type 1 ryanodine receptor, were not targeted. T cell priming and recall responses in vivo were not reduced. These data indicate that the nicotinic acid adenine dinucleotide phosphate/calcium signalling pathway is essential for the recruitment and the activation of autoaggressive effector T cells within their target organ. Interference with this signalling pathway suppresses the formation of autoimmune inflammatory lesions and thus might qualify as a novel strategy for the treatment of T cell mediated autoimmune diseases

Oxygen uptake kinetics in trained adolescent females

Little evidence exists with regard to the effect that exercise training has upon oxygen uptake kinetics in adolescent females. PURPOSE: The aim of the study was to compare [Formula: see text] and muscle deoxygenation kinetics in a group of trained (Tr) and untrained (Utr) female adolescents. METHOD: Twelve trained (6.4 ± 0.9 years training, 10.3 ± 1.4 months per year training, 5.2 ± 2.0 h per week) adolescent female soccer players (age 14.6 ± 0.7 years) were compared to a group (n = 8) of recreationally active adolescent girls (age 15.1 ± 0.6 years) of similar maturity status. Subjects underwent two, 6-min exercise transitions at a workload equivalent to 80 % of lactate threshold from a 3-min baseline of 10 W. All subjects had a passive rest period of 1 h between each square-wave transition. Breath-by-breath oxygen uptake and muscle deoxygenation were measured throughout and were modelled via a mono-exponential decay with a delay relative to the start of exercise. RESULT: Peak [Formula: see text] was significantly (p < 0.05) greater in the Tr compared to the Utr (Tr: 43.2 ± 3.2 mL kg(-1 )min(-1) vs. Utr: 34.6 ± 4.0 mL kg(-1 )min(-1)). The [Formula: see text] time constant was significantly (p < 0.05) faster in the Tr compared to the Utr (Tr: 26.3 ± 6.9 s vs. Utr: 35.1 ± 11.5 s). There was no inter-group difference in the time constant for muscle deoxygenation kinetics (Tr: 8.5 ± 3.0 s vs. Utr: 12.4 ± 8.3 s); a large effect size, however, was demonstrated (-0.804). CONCLUSION: Exercise training and/or genetic self-selection results in faster kinetics in trained adolescent females. The faster [Formula: see text] kinetics seen in the trained group may result from enhanced muscle oxygen utilisation

Neuroimaging standards for research into small vessel disease and its contribution to ageing and neurodegeneration: A united approach

Item does not contain fulltextCerebral small vessel disease (SVD) is a common accompaniment of ageing. Features seen on neuroimaging include recent small subcortical infarcts, lacunes, white matter hyperintensities, perivascular spaces, microbleeds, and brain atrophy. SVD can present as a stroke or cognitive decline, or can have few or no symptoms. SVD frequently coexists with neurodegenerative disease, and can exacerbate cognitive deficits, physical disabilities, and other symptoms of neurodegeneration. Terminology and definitions for imaging the features of SVD vary widely, which is also true for protocols for image acquisition and image analysis. This lack of consistency hampers progress in identifying the contribution of SVD to the pathophysiology and clinical features of common neurodegenerative diseases. We are an international working group from the Centres of Excellence in Neurodegeneration. We completed a structured process to develop definitions and imaging standards for markers and consequences of SVD. We aimed to achieve the following: first, to provide a common advisory about terms and definitions for features visible on MRI; second, to suggest minimum standards for image acquisition and analysis; third, to agree on standards for scientific reporting of changes related to SVD on neuroimaging; and fourth, to review emerging imaging methods for detection and quantification of preclinical manifestations of SVD. Our findings and recommendations apply to research studies, and can be used in the clinical setting to standardise image interpretation, acquisition, and reporting. This Position Paper summarises the main outcomes of this international effort to provide the STandards for ReportIng Vascular changes on nEuroimaging (STRIVE)