Publications by authors named "Dotson R"

Advances in artificial intelligence for computer vision hold great promise for increasing the scales at which ecological systems can be studied. The distribution and behavior of individuals is central to ecology, and computer vision using deep neural networks can learn to detect individual objects in imagery. However, developing supervised models for ecological monitoring is challenging because it requires large amounts of human-labeled training data, requires advanced technical expertise and computational infrastructure, and is prone to overfitting.

View Article and Find Full Text PDF

The role of membrane cholesterol in cellular function and dysfunction has been the subject of much inquiry. A few studies have suggested that cholesterol may slow oxygen diffusive transport, altering membrane physical properties and reducing oxygen permeability. The primary experimental technique used in recent years to study membrane oxygen transport is saturation-recovery electron paramagnetic resonance (EPR) oximetry, using spin-label probes targeted to specific regions of a lipid bilayer.

View Article and Find Full Text PDF

There is a surprising gap in knowledge regarding the mechanism of oxygen (O) diffusional delivery at the level of tissues and cells. Yet, the effectiveness of tumor radiotherapy, the success of tissue engineering, and healthy metabolism all require ample intracellular oxygen. Tissue-level diffusion takes place in a complex and crowded macromolecular environment.

View Article and Find Full Text PDF

Tumor radiotherapy relies on intracellular oxygen (O) to generate reactive species that trigger cell death, yet hypoxia is common in cancers of the breast. De novo lipid synthesis in tumors supports cell proliferation but also may lead to unusually high levels of the 16:1 palmitoleoyl (Y) phospholipid tail, which is two carbons shorter than the 18:1 oleoyl (O) tail abundant in normal breast tissue. Here, we use atomic resolution molecular dynamics simulations to test two hypotheses: (1) the shorter, 16:1 Y, tail of the de novo lipid biosynthesis product 1-palmitoyl,2-palmitoleoyl-phosphatidylcholine (PYPC) promotes lower membrane permeability relative to the more common lipid 1-palmitoyl,2-oleoylphosphatidylcholine (POPC), by reducing oxygen solubility in the interleaflet region, and (2) cholesterol further lessens the permeability of PYPC by reducing overall O solubility and promoting PYPC tail order adjacent to the rigid cholesterol ring system.

View Article and Find Full Text PDF

The hydrophobicity and high potency of many therapeutic agents makes them difficult to use effectively in clinical practice. This work focuses on conjugating phospholipid tails (2T) onto podophyllotoxin (P) and its analogue (N) using a linker and characterizing the effects of their incorporation into lipid-based drug delivery vehicles for triggered ultrasound delivery. Differential Scanning Calorimetry results show that successfully synthesized lipophilic prodrugs, 2T-P (~28 % yield) and 2T-N(~26 % yield), incorporate within the lipid membranes of liposomes.

View Article and Find Full Text PDF

Intracellular oxygenation is key to energy metabolism as well as tumor radiation therapy. Although integral proteins are ubiquitous in membranes, few studies have considered their effects on molecular oxygen permeability. Published experimental work with rhodopsin and bacteriorhodopsin has led to the hypothesis that integral proteins lessen membrane oxygen permeability, as well as the permeability of the lipid region.

View Article and Find Full Text PDF
Article Synopsis
  • Aberrations in cholesterol levels are linked to various diseases, affecting how cells use oxygen.
  • Previous studies hinted that cholesterol in cell membranes could influence oxygen delivery, but more research is needed to understand its significance.
  • Using molecular dynamics simulations, the study examines how cholesterol affects oxygen movement through cell membranes, finding that cholesterol reduces oxygen permeability and suggesting that earlier EPR measurements might have underestimated this effect.
View Article and Find Full Text PDF

Cholesterol is widely known to alter the physical properties and permeability of membranes. Several prior works have implicated cell membrane cholesterol as a barrier to tissue oxygenation, yet a good deal remains to be explained with regard to the mechanism and magnitude of the effect. We use molecular dynamics simulations to provide atomic-resolution insight into the influence of cholesterol on oxygen diffusion across and within the membrane.

View Article and Find Full Text PDF

Purpose: To evaluate the efficacy of photobiomodulation (PBM) treatment for patients with dry age-related macular degeneration (AMD).

Methods: Assessments on 42 eyes with dry AMD (age related eye disease study (AREDS) 2-4) were conducted. Multiwavelength light emitting diode (LED) light comprising of yellow (590 nm), red (670 nm) and near-infrared (790 nm) bandwidths was applied to subjects' eyes for a treatment course of 3 weeks.

View Article and Find Full Text PDF

Francisella tularensis is an important human pathogen responsible for causing tularemia. F. tularensis has long been developed as a biological weapon and is now classified as a category A agent by the Centers for Disease Control because of its possible use as a bioterror agent.

View Article and Find Full Text PDF

Francisella tularensis, the causative agent of tularemia, is one of the deadliest agents of biological warfare and bioterrorism. Extremely high virulence of this bacterium is associated with its ability to dampen or subvert host innate immune response. The objectives of this study were to identify factors and understand the mechanisms of host innate immune evasion by F.

View Article and Find Full Text PDF

Introduction: Mechanically ventilated trauma patients have a high risk for the development of ventilator-associated pneumonia (VAP). We have recently reported that reduced plasma protein C (PC) levels early after trauma/shock are associated with coagulopathy and mortality. Furthermore, trauma patients with tissue injury and shock are at higher risk for the development of VAP.

View Article and Find Full Text PDF

Objective: To investigate the frequency and outcomes of ventilated patients with newly acquired large burdens of Pseudomonas aeruginosa and to test the hypothesis that large quantities of bacteria are associated with adverse patient outcomes.

Design: A prospective, single-center, observational, cohort study.

Setting: Medical-surgical intensive care units in a tertiary care university hospital.

View Article and Find Full Text PDF

Background: Increased plasminogen activator inhibitor-1 (PAI-1) concentrations are found in bronchoalveolar lavage (BAL) fluids from patients with ventilator-associated pneumonia or acute respiratory distress syndrome. The authors hypothesized that PAI-1 concentrations were associated with increased mortality in patients with either Pseudomonas aeruginosa-induced ventilator-associated pneumonia or tracheobronchial colonization.

Methods: In a prospective cohort study, daily aspirates from intubated patients were cultured for P.

View Article and Find Full Text PDF

The purpose of this study is to evaluate both painless and painful sensory transmission in patients with Complex Regional Pain Syndrome (CRPS) using the automated electrodiagnostic sensory Nerve Conduction Threshold (sNCT) test. This test generates reliable, painless Current Perception Threshold (CPT) and atraumatic Pain Tolerance Threshold (PTT) measures. Standardized CPT and PTT measures using constant alternating current sinusoid waveform stimulus at 3 different frequencies 5 Hz, 250 Hz, and 2 kHz (Neurometer CPT/C Neurotron, Inc.

View Article and Find Full Text PDF

In animal production systems (poultry, beef, and swine), current production, storage, and disposal techniques present a challenge to manage wastes to minimize the emissions of trace gases within relatively small geographical areas. Physical and chemical parameters were measured on primary and secondary lagoons on three different swine farming systems, three replicates each, in the Central Great Basin of the United States to determine ammonia (NH3) emissions. Nutrient concentrations, lagoon water temperature, and micrometeorological data from these measurements were used with a published process model to calculate emissions.

View Article and Find Full Text PDF

Postural orthostatic tachycardia syndrome (POTS) is characterized by excessive tachycardia during orthostasis. To test the hypothesis that patients with POTS have decreased sympathetic neural responses to baroreflex stimuli, we measured heart rate (HR) and muscle sympathetic nerve activity (MSNA) responses to three baroreflex stimuli including vasoactive drug boluses (modified Oxford technique), Valsalva maneuver, and head-up tilt (HUT) in POTS patients and healthy control subjects. The MSNA response to the Valsalva maneuver was significantly greater in the POTS group (controls, 26 +/- 7 vs.

View Article and Find Full Text PDF

Background: Nerve injury results in increases in spinal glutamate, which opens the NMDA ionophore channel, causing an influx of calcium. A glycine-binding site must be occupied for the channel to open. GV196771 is a selective antagonist of the glycine-binding site of the NMDA ionophore.

View Article and Find Full Text PDF

The in vitro self-assembly of multicellular spheroids generates highly organized structures in which the three-dimensional structure and differentiated function frequently mimic that of in vivo tissues. This has led to their use in such diverse applications as tissue regeneration and drug therapy. Using Smoluchowski-like rate equations, herein we present a model of the self-aggregation of DU 145 human prostate carcinoma cells in liquid-overlay culture to elucidate some of the physical parameters affecting homotypic aggregation in attachment-dependent cells.

View Article and Find Full Text PDF

The synthesis of substituted phenoxyphenyl oxamic acid derivatives related to L-thyronine (L-T3) is described. The in vitro and in vivo cholesterol lowering and cardiovascular effects of these compounds are presented and discussed.

View Article and Find Full Text PDF

Evidence has accumulated to support a model for odorant detection in which individual olfactory receptor neurons (ORNs) express one of a large family of G protein-coupled receptor proteins that are activated by a small number of closely related volatile chemicals. However, the issue of whether an individual ORN expresses one or multiple types of receptor proteins has yet to be definitively addressed. Physiological data indicate that some individual ORNs can be activated by odorants differing substantially in structure and/or perceived quality, suggesting multiple receptors or one nonspecific receptor per cell.

View Article and Find Full Text PDF