Publications by authors named "Stait-Gardner T"

Accurate delineation of gross tumor volumes remains a barrier to radiotherapy dose escalation and boost dosing in the treatment of solid tumors, such as prostate cancer. Magnetic resonance imaging (MRI) of tumor targets has the power to enable focal dose boosting, particularly when combined with technological advances such as MRI-linear accelerator. Fibroblast activation protein (FAP) is overexpressed in stromal components of >90% of epithelial carcinomas.

View Article and Find Full Text PDF

Gas exchange mechanisms play crucial roles in maintaining fruit post-harvest quality in perishable fruit such as strawberry (Fragaria×ananassa Duch.) and blueberry (Vaccinium corymbosum L.).

View Article and Find Full Text PDF

This proof-of-concept study looked at the feasibility of using a thiol-water proton exchange (i.e., CEST) MRI contrast to detect in vivo hepatic -acetylcysteine (NAC) uptake.

View Article and Find Full Text PDF

To explore diversity in cold hardiness mechanisms, high resolution magnetic resonance imaging (MRI) was used to visualise freezing behaviours in wintering Daphne kamtschatica var. jezoensis flower buds, which have naked florets and no bud scales. MRI images showed that anthers remained stably supercooled to the range from -14 to -21°C or lower while most other tissues froze by -7°C.

View Article and Find Full Text PDF

Explicit phenomenological solutions to recurrence relations for the bulk transverse and longitudinal magnetization found using the Torrey-Bloch equations with relaxation effects are used to investigate nuclear magnetic resonance (NMR) diffusion measurements. Of particular interest are steady state NMR (self-)diffusion measurements that reduce experimental time that can extend the techniques to quickly reacting systems. The solutions for bulk transverse and longitudinal magnetization presented here are used to investigate the average behavior of the transverse and longitudinal magnetization in forming a steady state and are used to derive new expressions for the steady state longitudinal magnetization.

View Article and Find Full Text PDF

Spin relaxation is one of the most fundamental concepts in magnetic resonance and is one of the key NMR "observables" providing critical motional information in chemical systems and, by extension, diagnostic information in clinical imaging. Yet, it can be difficult to find accurate conceptual descriptions of the two relaxation processes-longitudinal and transverse-in the NMR or MRI literature that explain why these processes are also referred to as "spin-lattice" and "spin-spin" relaxation, respectively. Often, the explanations provided in terms of energy levels, energy exchange, and the loss of phase coherence are inaccurate oversimplifications of quantum mechanical concepts and are thus incomplete and, at times, even contradictory.

View Article and Find Full Text PDF

Amide-, amine-, and hydroxyl-water proton exchange can generate MRI contrast through chemical exchange saturation transfer (CEST). In this study, we show that thiol-water proton exchange can also generate quantifiable CEST effects under near-physiological conditions (pH = 7.2 and 37°C) through the characterization of the pH dependence of thiol proton exchange in phosphate-buffered solutions of glutathione, cysteine, and N-acetylcysteine.

View Article and Find Full Text PDF

Placental growth factor (PlGF) is decreased in early gestation of pregnant women who subsequently develop pre-eclampsia. In this study, pre-emptive treatment with PlGF to prevent pre-eclampsia was evaluated in an in vivo rodent model of experimental pre-eclampsia (EPE) induced by TNF-α and in an in vitro model of human first-trimester trophoblast invasion. Pregnant C57/BL6 mice were treated with recombinant mouse placental growth factor-2 (rmPlGF-2) 100 μg/kg/day IP from gestational day (gd) 10.

View Article and Find Full Text PDF

Current clinical MRI techniques in rectal cancer have limited ability to examine cancer stroma. The differentiation of tumour from desmoplasia or fibrous tissue remains a challenge. Standard MRI cannot differentiate stage T1 from T2 (invasion of muscularis propria) tumours.

View Article and Find Full Text PDF

A binomial-like block based multiple suppression NMR pulse sequence, termed MULTI-GATE-FSB, that is simple to implement with outstanding suppression performance for multiple solvent signals (or multiple resonances) is investigated. The sequence was tested on two water-alcohol solvent systems, and a standard lysozyme sample, with suppression of three or four regions (though it is extendable to any number of regions). The suppression of all solvent signals was possible in the alcohol-water systems tested with both long and short recycle delays and without the requirement for lengthy presaturation pulses.

View Article and Find Full Text PDF

Control of freezing in plant tissues is a key issue in cold hardiness mechanisms. Yet freeze-regulation mechanisms remain mostly unexplored. Among them, ice nucleation activity (INA) is a primary factor involved in the initiation and regulation of freezing events in plant tissues, yet the details remain poorly understood.

View Article and Find Full Text PDF

Abnormal development of the placenta is postulated to be central to the aetiology of preeclampsia. This study investigates changes in placental histopathology in mouse models of preeclampsia compared to the morphology using magnetic resonance microscopy (MRM) (11.7 T) of intact ex vivo tissue followed by 3D analysis of the image data.

View Article and Find Full Text PDF

Magnetic resonance imaging (MRI) is an established technique for neuroanatomical analysis, being particularly useful in the medical sciences. However, the application of MRI to evolutionary neuroscience is still in its infancy. Few magnetic resonance brain atlases exist outside the standard model organisms in neuroscience and no magnetic resonance atlas has been produced for any reptile brain.

View Article and Find Full Text PDF

Conventionally, arrayed nuclear magnetic resonance experiments, such as diffusion and relaxation, are performed with the same number of scans (NS) at each iteration despite the signal-to-noise ratio being more than sufficient for many of the iterations. Here, we propose a simple yet effective approach that significantly shortens experimental times by varying NS through the arrayed experiments while keeping the signal-to-noise ratio essentially the same and retaining experimental accuracy.

View Article and Find Full Text PDF

A new family of binomial-like inversion sequences, named jump-and-return sandwiches (JRS), has been developed by inserting a binomial-like sequence into a standard jump-and-return sequence, discovered through use of a stochastic Genetic Algorithm optimisation. Compared to currently used binomial-like inversion sequences (e.g.

View Article and Find Full Text PDF

Tracer compounds used for studying solute transport should ideally have identical functions and transport properties to the molecules they are designed to mimic. Unfortunately, the xylem-mobile tracer compounds currently used to infer solute transport mechanisms in botanical specimens such as the fruit of the grapevine, Vitis vinifera L., are typically xenobiotic and have difficulty exiting the xylem during berry ripening.

View Article and Find Full Text PDF

The brain plays a critical role in a wide variety of functions including behaviour, perception, motor control, and homeostatic maintenance. Each function can undergo different selective pressures over the course of evolution, and as selection acts on the outputs of brain function, it necessarily alters the structure of the brain. Two models have been proposed to explain the evolutionary patterns observed in brain morphology.

View Article and Find Full Text PDF

Preeclampsia is a hypertensive disorder of pregnancy. It is associated with abnormal placentation via poor placental invasion of the uterine vasculature by trophoblast cells, leading to poor placental perfusion, oxidative stress, and inflammation, all of which are implicated in its pathogenesis. A dyslipidemia characterized by low plasma levels of high-density lipoproteins (HDL) and elevated triglycerides has been described in preeclampsia.

View Article and Find Full Text PDF

Phenotypic traits such as ornaments and armaments are generally shaped by sexual selection, which often favours larger and more elaborate males compared to females. But can sexual selection also influence the brain? Previous studies in vertebrates report contradictory results with no consistent pattern between variation in brain structure and the strength of sexual selection. We hypothesize that sexual selection will act in a consistent way on two vertebrate brain regions that directly regulate sexual behaviour: the medial preoptic nucleus (MPON) and the ventromedial hypothalamic nucleus (VMN).

View Article and Find Full Text PDF

NMR diffusion measurements (or dNMR) provide a powerful tool for analysis of solution organization and microgeometry of the environment by probing random molecular motion. Being a very versatile method, dNMR can be applied to a large variety of samples and systems. Here, a brief introduction into dNMR and a summary of recent advances in the field are presented.

View Article and Find Full Text PDF

Microencapsulated islets are usually injected free-floating into the peritoneal cavity, so the position of the grafts remains elusive after transplantation. This study aims to assess magnetic resonance imaging (MRI) as a noninvasive means to track microencapsulated insulin producing cells following transplantation. Encapsulated insulin producing cells (MIN6 and human islets) were labelled with magnetic microspheres (MM), assessed for viability and insulin secretion, and imaged in vitro using a clinical grade 3 T MRI and in vivo using both clinical grade 3 T and research grade 11.

View Article and Find Full Text PDF

Quantitative MRI is often used to analyse multicomponent systems. The analysis requires the contributions from different species to be isolated. Species with distinct chemical shifts can be separated by using a low acquisition bandwidth, which is easy to achieve in common quantitative imaging protocols.

View Article and Find Full Text PDF

The structure and dynamics of hydrogen-bonded structures are of significant importance in understanding many binary mixtures. Since self-diffusion is very sensitive to changes in the molecular weight and shape of the diffusing species, hydrogen-bonded associated structures in dimethylsulfoxide-methanol (DMSO-MeOH) and DMSO-ethanol (DMSO-EtOH) mixtures are investigated using nuclear magnetic resonance (NMR) diffusion experiments and molecular dynamics (MD) simulations over the entire composition range at 298 K. The self-diffusion coefficients of DMSO-MeOH and DMSO-EtOH mixtures decrease by up to 15% and 10%, respectively, with DMSO concentration, indicating weaker association as compared to DMSO-water mixtures.

View Article and Find Full Text PDF

Here, a new amphiphilic magnetic resonance imaging (MRI) contrast agent, a Gd(III)-chelated diethylenetriaminepentaacetic acid conjugated to two branched alkyl chains via a dopamine spacer, Gd-DTPA-dopamine-bisphytanyl (Gd-DTPA-Dop-Phy), which is readily capable of self-assembling into liposomal nanoassemblies upon dispersion in an aqueous solution, is reported. In vitro relaxivities of the dispersions were found to be much higher than Magnevist, a commercially available contrast agent, at 0.47 T but comparable at 9.

View Article and Find Full Text PDF