804 research outputs found
Measuring visual cortical oxygenation in diabetes using functional near-infrared spectroscopy
Aims: Diabetes mellitus affects about 6% of the worldâs population, and the chronic complications of the disease may result in macro- and micro-vascular changes. The purpose of the current study was to shed light on visual cortical oxygenation in diabetic individuals. We then aimed to compare the haemodynamic response (HDR) to visual stimulation with glycaemic control, given the likelihood of diabetic individuals suffering from such macro- and micro-vascular insult.
Methodology: Thirty participants took part in this explorative study, fifteen of whom had diabetes and fifteen of whom were non-diabetic controls. The HDR, measured as concentrations of oxyhaemoglobin [HbO] and deoxyhaemoglobin [HbR], to visual stimulation was recorded over the primary visual cortex (V1) using a dual-channel oximeter. The stimulus comprised a pattern-reversal checkerboard presented in a block design. Participantsâ mean glycated haemoglobin (HbA1c) level (±SD) was 7.2±0.6% in the diabetic group and 5.5±0.4% in the non-diabetic group. Raw haemodynamic data were normalised to baseline, and the last 15 s of data from each âstimulus onâ and âstimulus offâ condition were averaged over seven duty cycles for each participant.
Results: There were statistically significant differences in â[HbO] and â[HbR] to visual stimulation between diabetic and non-diabetic groups (p<0.05). In the diabetic group, individuals with type 1 diabetes displayed an increased [HbO] (p<0.01) and decreased [HbR] (p<0.05) compared to their type 2 counterparts. There was also a linear relationship between both â[HbO] and â[HbR] as a function of HbA1c level (p<0.0005).
Conclusions: Our findings suggest that fNIRS can be used as a quantitative measure of cortical oxygenation in diabetes. Diabetic individuals have a larger HDR to visual stimulation compared to non-diabetic individuals. This increase in â[HbO] and decrease in â[HbR] appears to be correlated with HbA1c level
Distribution and Abundance of Larval Burbot and Deepwater Sculpin in Lake Michigan
Samples from seven locations at depths to 21 m, collected over periods of up to 8 years, were used to describe the nearshore distribution and abundance of burbot Lota lota and deepwater sculpin Myoxocephalus thompsoni larvae in Lake Michigan. Based upon powerâplantâentrainment samples and field collections, burbot larvae (3.0â7.5 mm) occurred from late March to midâJune, most abundantly in April and May, and most often at water temperatures of 6â12 C. Larvae were collected from the 0.5â to 13.5âm depth strata as far lakeward as the 21âm bottom contour, the limit of offshore sampling. In eastern Lake Michigan, highest densities (up to 843 larvae/1,000 m3) were at the 1âm contour; in Green Bay, up to 24,000 larvae/1,000 m3 were detected near the Bark River. High densities of burbot larvae at bottom depths 3 m and less indicated inshore spawning and river spawning at some sites. Deepwater sculpin larvae first occurred in early February and were common in March and April entrainment samples. Larvae (8.0â22.0 mm) were in nearshore waters usually through May at depth strata of 0.5 to 17 m as far lakeward as the 18âm bottom contour. Most larvae occurred at water temperatures below 6 C. Field densities were low, 5 to 78 larvae/1,000 m3. Deepwater sculpin larvae were pelagic and were dispersed over great distances by currents.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141932/1/tafs0162.pd
Measuring the foveal avascular zone in diabetes: a study using optical coherence tomography angiography
AIMS/INTRODUCTION: Diabetes is a global issue that currently affects 425âmillion people worldwide. One observable microvascular complication of this condition is a change in the foveal avascular zone (FAZ). In this study, we used optical coherence tomography angiography to investigate the effect of diabetes on the FAZ. MATERIALS AND METHODS: A total of 11 participants with diabetes and 11 participants without diabetes took part in this study. Participants in both groups were matched for age (Pâ=â0.217) and sex (Pâ=â0.338), and had no history of ocular disease. Macular optical coherence tomography angiography (OCTâA) scans of participantsâ right and left eyes were taken. Glycosylated hemoglobin (HbA(1c)) and blood glucose levels were also measured. The FAZ area was manually segmented at the levels of the superficial capillary plexus (FAZ(SCP)) and deep capillary plexus (FAZ(DCP)). RESULTS: There was a strong relationship between the FAZ area of participantsâ right and left eyes (Pââ€â0.001) in both diabetes and nonâdiabetes groups. In the diabetes group, the FAZ(SCP) (Pâ=â0.047) and FAZ(DCP) (Pâ=â0.011) areas was significantly larger than in the nonâdiabetes group. Moreover, multiple linear regression analysis predicted a 0.07âmm(2) increase in the FAZ(SCP) and FAZ(DCP) areas of individuals with diabetes for every 1% increase in their HbA(1c) level. CONCLUSIONS: Our findings show that there is enlargement of the FAZ in individuals with diabetes compared with individuals without diabetes. In the diabetes group, this enlargement appears to be correlated with HbA(1c) level. OCTâA imaging could, therefore, be a useful tool to monitor the FAZ and identify potential early microvasculopathy in diabetes
Light-Cone Quantization of the Liouville Model
We present the quantization of the Liouville model defined in light-cone
coordinates in (1,1) signature space. We take advantage of the representation
of the Liouville field by the free field of the Backl\"{u}nd transformation and
adapt the approch by Braaten, Curtright and Thorn.
Quantum operators of the Liouville field ,
, , are constructed consistently in
terms of the free field. The Liouville model field theory space is found to be
restricted to the sector with field momentum , , which
is a closed subspace for the Liouville theory operator algebra.Comment: 16 p, EFI-92-6
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The stealth episome: suppression of gene expression on the excised genomic island PPHGI-1 from Pseudomonas syringae pv. phaseolicola
Pseudomonas syringae pv. phaseolicola is the causative agent of halo blight in the common bean, Phaseolus vulgaris. P. syringae pv. phaseolicola race 4 strain 1302A contains the avirulence gene avrPphB (syn. hopAR1), which resides on PPHGI-1, a 106 kb genomic island. Loss of PPHGI-1 from P. syringae pv. phaseolicola 1302A following exposure to the hypersensitive resistance response (HR) leads to the evolution of strains with altered virulence. Here we have used fluorescent protein reporter systems to gain insight into the mobility of PPHGI-1. Confocal imaging of dual-labelled P. syringae pv. phaseolicola 1302A strain, F532 (dsRFP in chromosome and eGFP in PPHGI-1), revealed loss of PPHGI-1::eGFP encoded fluorescence during plant infection and when grown in vitro on extracted leaf apoplastic fluids. Fluorescence-activated cell sorting (FACS) of fluorescent and non-fluorescent PPHGI-1::eGFP F532 populations showed that cells lost fluorescence not only when the GI was deleted, but also when it had excised and was present as a circular episome. In addition to reduced expression of eGFP, quantitative PCR on sub-populations separated by FACS showed that transcription of other genes on PPHGI-1 (avrPphB and xerC) was also greatly reduced in F532 cells harbouring the excised PPHGI-1::eGFP episome. Our results show how virulence determinants located on mobile pathogenicity islands may be hidden from detection by host surveillance systems through the suppression of gene expression in the episomal state
Persistent enteric murine norovirus infection is associated with functionally suboptimal virus-specific CD8 T cell responses
Norovirus (NV) gastroenteritis is a major contributor to global morbidity and mortality, yet little is known about immune mechanisms leading to NV control. Previous studies using the murine norovirus (MNV) model have established a key role for T cells in MNV clearance. Despite these advances, important questions remain regarding the magnitude, location, and dynamics of the MNV-specific T cell response. To address these questions, we identified MNV-specific major histocompatibility complex (MHC) class I immunodominant epitopes using an overlapping peptide screen. One of these epitopes (amino acids 519 to 527 of open reading frame 2 [ORF2(519-527)]) was highly conserved among all NV genogroups. Using MHC class I peptide tetramers, we tracked MNV-specific CD8 T cells in lymphoid and mucosal sites during infection with two MNV strains with distinct biological behaviors, the acutely cleared strain CW3 and the persistent strain CR6. Here, we show that enteric MNV infection elicited robust T cell responses primarily in the intestinal mucosa and that MNV-specific CD8 T cells dynamically regulated the expression of surface molecules associated with activation, differentiation, and homing. Furthermore, compared to MNV-CW3 infection, chronic infection with MNV-CR6 resulted in fewer and less-functional CD8 T cells, and this difference was evident as early as day 8 postinfection. Finally, MNV-specific CD8 T cells were capable of reducing the viral load in persistently infected Rag1(â/â) mice, suggesting that these cells are a crucial component of NV immunity. Collectively, these data provide fundamental new insights into the adaptive immune response to two closely related NV strains with distinct biological behaviors and bring us closer to understanding the correlates of protective antiviral immunity in the intestine
Social media for physiotherapy clinics: considerations in creating a Facebook page
Social media websites play a prominent role in modern society, and the most popular of these websites is Facebook. Increasingly, physiotherapy clinics have begun to utilize Facebook in order to create pages to publicize their services. There are many factors to consider in the planning, implementing, and maintenance of Facebook pages for physiotherapy clinics, including ethical and privacy issues. The primary purpose of creating a page must be clearly defined, with dedicated clinicians given adequate time to manage the page. This technical article discusses these factors and summarizes the experiences at the University of Otago, New Zealand, in creating a Facebook page for the physiotherapy clinic and provides suggestions for physiotherapy clinicians in operating a Facebook page
The No-Triangle Hypothesis for N=8 Supergravity
We study the perturbative expansion of N=8 supergravity in four dimensions
from the viewpoint of the ``no-triangle'' hypothesis, which states that
one-loop graviton amplitudes in N=8 supergravity only contain scalar box
integral functions. Our computations constitute a direct proof at six-points
and support the no-triangle conjecture for seven-point amplitudes and beyond.Comment: 43page
Production, characterization, and antigen specificity of recombinant 62-71-3, a candidate monoclonal antibody for rabies prophylaxis in humans
Rabies kills many people throughout the developing world every year. The murine monoclonal antibody (mAb) 62-71-3 was recently identified for its potential application in rabies postexposure prophylaxis (PEP). The purpose here was to establish a plant-based production system for a chimeric mouse-human version of mAb 62-71-3, to characterize the recombinant antibody and investigate at a molecular level its interaction with rabies virus glycoprotein. Chimeric 62-71-3 was successfully expressed in Nicotiana benthamiana. Glycosylation was analyzed by mass spectroscopy; functionality was confirmed by antigen ELISA, as well as rabies and pseudotype virus neutralization. Epitope characterization was performed using pseudotype virus expressing mutagenized rabies glycoproteins. Purified mAb demonstrated potent viral neutralization at 500 IU/mg. A critical role for antigenic site I of the glycoprotein, as well as for two specific amino acid residues (K226 and G229) within site I, was identified with regard to mAb 62-71-3 neutralization. Pseudotype viruses expressing glycoprotein from lyssaviruses known not to be neutralized by this antibody were the controls. The results provide the molecular rationale for developing 62-71-3 mAb for rabies PEP; they also establish the basis for developing an inexpensive plant-based antibody product to benefit low-income families in developing countries.âBoth, L., van Dolleweerd, C., Wright, E., Banyard, A. C., Bulmer-Thomas, B., Selden, D., Altmann, F., Fooks, A. R., Ma, J. K.-C. Production, characterization, and antigen specificity of recombinant 62-71-3, a candidate monoclonal antibody for rabies prophylaxis in humans
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