White Light Exposure Research Articles

Assessment of diurnal melatonin, cortisol, activity, and sleep−wake cycle in patients with and without diabetic retinopathy

ObjectiveTo assess the diurnal melatonin, cortisol, and activity/rest levels, as well as sleep quality, in patients with and without nonproliferative diabetic retinopathy (DR). MethodsWe included 25 diabetic patients with DR and 29 without DR. A total of 21 healthy subjects constituted the control group. We assessed the circadian rhythm by actigraphy and diurnal salivary melatonin and cortisol measurements. Sleep quality was evaluated by actigraphy and the Pittsburgh Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. Light exposure was quantified by actigraphy. The primary outcome was peak salivary melatonin level. Secondary outcomes were mean melatonin and cortisol levels during dark hours, activity−rest rhythm, sleep quality, as well as level of white, red, green, and blue light exposure. ResultsPeak melatonin concentration at 04:00 and mean nocturnal melatonin level were significantly reduced in all diabetic patients, regardless of retinopathy stage (p < 0.001). Levels of light exposures during dark hours were not significantly different in patients with and without DR and healthy controls. Only patients with DR showed increased intradaily variability in their activity−rest interval, indicating circadian misalignment (p = 0.04). Neither the objective actigraphic sleep quality parameters nor the subjective PSQI or ESS scores were significantly different between healthy controls and diabetic patients. ConclusionsReduced nocturnal melatonin concentration and increased fragmentation of activity−rest intervals revealed circadian rhythm disturbance in diabetic patients with DR.

Investigation of Dose-Response Relationships for Effects of White Light Exposure on Correlates of Alertness and Executive Control during Regular Daytime Working Hours.

To date, it is largely unknown which light settings define the optimum to steer alertness and cognitive control during regular daytime working hours. In the current article, we used a multimeasure approach combined with a relatively large sample size (N = 60) and a large range of intensity levels (20-2000 lux at eye level) to investigate the dose-dependent relationship between light and correlates of alertness and executive control during regular working hours in the morning and afternoon. Each participant was exposed to a single-intensity light level for 1 h after a 30-min baseline phase (100 lux at the eye) in the morning and afternoon (on separate days) during their daily routine. Results revealed no clear dose-dependent relationships between 1-h daytime light exposure and correlates of alertness or executive control. Subjective correlates showed only very modest linear relationships with the log-transformed illuminance, and we found no significant effects of light intensity on the behavioral and physiological indicators. Overall, these results suggest that daytime exposure to more intense light, at least for 1 h of exposure, may not systematically benefit alertness or executive functioning. However, future research is required to investigate effects of longer exposure durations and potential moderations by prior light exposure, personal characteristics, and spectrum.

Exposure to excessive blue LED light damages retinal pigment epithelium and photoreceptors of pigmented mice

To determine the characteristics of the damages of the retinal pigment epithelium (RPE) and photoreceptors of pigmented mice induced by exposure to blue light emitting diode (LED) light, and to determine the mechanisms causing the damages. Exposure to blue LED light for 3 days induced retinal damage, and the characteristics of the damage differed from that induced by white fluorescent light exposure. Ophthalmoscopy showed that blue LED exposure for 3 days induced white spots on the retina, and histological examinations showed materials accumulated at the IS/OS junction of the photoreceptors. The accumulated materials were stained by ionized calcium binding adapter molecule-1 (Iba-1), a marker for macrophages. The debris was also positive for periodic acid-Schiff (PAS). An enlarging the area of RPE was detected just after the blue LED exposure especially around the optic nerve, and this led to a secondary degeneration of the photoreceptors. Exposure of pigmented mice to 3 consecutive days of blue LED light will cause RPE and photoreceptor damage. The damage led to an accumulation of macrophages and drusen-like materials around the outer segments of the photoreceptors. This blue light exposed model may be useful for investigating the pathogenesis of non-exudative age-related macular degeneration.

Automatic cell fusion via optically-induced dielectrophoresis and optically-induced locally-enhanced electric field on a microfluidic chip.

Cell fusion technology has been exploited in a wide variety of biomedical applications, and physical, chemical, and biological approaches can all be used to fuse two different types of cells; however, no current technique is adept at inducing both cell pairing and fusion at high efficiencies and yields. Hence, we developed a new method featuring the use of optically induced dielectrophoresis (ODEP) in conjunction with an optically induced, locally enhanced electric field for accurate and automatic cell pairing and fusion on a microfluidic device. After pairing cells via ODEP, a locally enhanced electric field generated by "virtual electrodes" by projecting light patterns was enacted to induce a proper transmembrane potential at the cell contact area such that cell fusion could be triggered by white light exposure. As a fusion yield of 9.67% was achieved between Pan1 and A549 cells, we believe that this may be a promising technique for automatically fusing different cell types.

White light emitting diode suppresses proliferation and induces apoptosis in hippocampal neuron cells through mitochondrial cytochrome c oxydase‐mediated IGF‐1 and TNF‐α pathways

Light emitting diode (LED) light has been used in the treatment of traumatic brain injury, neural degenerative diseases and psychiatric disorders. A growing number of studies indicate that blue LED light affects cell proliferation and apoptosis in photosensitive cells and cancer cells, yet it remains unknown whether white LED light exposure impacts hippocampal neural cell proliferation and apoptosis. The present study was aimed to demonstrate the effect of white LED light exposure on viability of hippocampal neural cells and to reveal the underlying mechanisms. Cells exposed to white LED light for 24 h showed reduced viability, with higher apoptotic rate and a cell cycle arrest at G0/G1 phase. White LED light activated mitochondrial cytochrome c oxidase (Cco), in association with enhanced ATP synthase activity and elevated intracellular ATP concentration. Also, reactive oxygen species (ROS) and nitric oxide (NO) production were increased, accompanied by higher calcium concentration and lower mitochondrial membrane potential. Concurrently, the mRNA expression and the concentration of IGF‐1 were decreased, while that of TNF‐α were increased, in light‐exposed cells, which was supported by the luciferase activity of both gene promoters. The down‐stream mitogen‐activated protein kinase (MAPK), AKT/mTOR pathways were inhibited, in association with an activation of apoptotic caspase 3. N‐Acetylcysteine, a ROS scavenger, protected the cells from LED light‐induced cellular damage, with rescued cell viability and restored mRNA expression of IGF‐1 and TNF‐α. Our data demonstrate that white LED light suppresses proliferation and induces apoptosis in hippocampal neuron cells through mitochondrial Cco/ROS‐mediated IGF‐1 and TNF‐α pathways.Support or Funding InformationThe National Basic Research Program of China (2012CB124703), the Special Fund for Agro‐scientific Research in the Public Interest (201003011), the Fundamental Research Funds for the Central Universities (KYZ201212) and the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD).This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

White Light Induced E/Z-Photoisomerization of Diphenylamine-Tethered Fluorescent Stilbene Derivatives: Synthesis, Photophysical, and Electrochemical Investigation

A facile synthesis and detailed photophysical investigation of E/Z-isomerization of fluorescent diphenylamine tethered stilbene derivatives (DPASs) under white light exposure have been carried out to understand the effect on fluorescence, electrochemical properties, and photostability under various activation/deactivation pathways. In solution state, in the dark, the E-isomer of DPASs (6a-d) exhibited high fluorescence quantum yields (Φfl ≈ 53% to 60% in DMSO). However, on white light exposure, 1H NMR and HPLC studies revealed that pure E-isomer of the DPAS 6a (∼9.5 mM) started converting into its Z-form by photoisomerization until it reaches to nearly equilibrium. At low concentrations (∼10 μM), the absorption band of the pure E-isomer in the range of 350-450 nm gradually decreased to adopt Z-conformation 6a' until a photostationary state was reached. The structure of the E-isomer 6a was unequivocally confirmed by X-ray diffraction analysis. The synthesized DPAS compounds 6a-d possessed positive solvatochromic properties, two photon absorption properties, and good thermal stability. The electrochemical investigations using DPASs showed reversible oxidation resulting in formation of a stable radical cation. Owing to useful photophysical, electrochemical and thermal properties, these DPAS derivatives are suitable for their application in biomedical imaging as well as in fabrication of electroluminescent materials.

Ultraviolet-assisted cold poling of Pb(Zr0.52Ti0.48)O3 films

This paper discusses the advantages of a room-temperature poling procedure during exposure to ultraviolet light for Pb(Zr0.52Ti0.48)O3 (PZT) films. The results of these experiments include the following: for 1.7-µm-thick chemical solution-deposited PZT films, the saturation photocurrent density after a 10 min white light exposure (190–1900 nm) (no DC bias field applied) increased up to 0.066 µA/cm2 with increasing Cr thickness of top electrode in Cr/Pt bilayer electrodes. Furthermore, the d33,f piezoelectric coefficients for UV-poled samples were 40 and 20% higher than those achieved from field-only poling at either room temperature or 150 °C. Additionally, the development of an internal bias field and pinching were investigated in major and minor polarization–electric field loops. It was found that ultraviolet illumination during the poling process produced photoinduced charge carriers that became trapped by local defects and/or grain boundaries in the films.

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

Monitoring the Effects of Illumination on the Structure of Conjugated Polymer Gels Using Neutron Scattering.

We demonstrate a protocol to effectively monitor the gelation process of a high concentration solution of conjugated polymer both in the presence and absence of white light exposure. By instituting a controlled temperature ramp, the gelation of these materials can be precisely monitored as they proceed through this structural evolution, which effectively mirrors the conditions experienced during the solution deposition phase of organic electronic device fabrication. Using small angle neutron scattering (SANS) and ultra-small angle neutron scattering (USANS) along with appropriate fitting protocols we quantify the evolution of select structural parameters throughout this process. Thorough analysis indicates that continued light exposure throughout the gelation process significantly alters the structure of the ultimately formed gel. Specifically, the aggregation process of poly(3-hexylthiophene-2,5-diyl) (P3HT) nano-scale aggregates is negatively affected by the presence of illumination, ultimately resulting in the retardation of growth in conjugated polymer microstructures and the formation of smaller scale macro-aggregate clusters.

White light emitting diode suppresses proliferation and induces apoptosis in hippocampal neuron cells through mitochondrial cytochrome c oxydase-mediated IGF-1 and TNF-α pathways

Light emitting diode (LED) light has been tested to treat traumatic brain injury, neural degenerative diseases and psychiatric disorders. Previous studies indicate that blue LED light affects cell proliferation and apoptosis in photosensitive cells and cancer cells. In this study, we demonstrate that white LED light exposure impaired proliferation and induced apoptosis in HeLa and HT-22 hippocampal neural cells, but not C2C12 cells. Furthermore, the mechanisms underlying the effect of white LED light exposure on HT-22 cells were elucidated. In HeLa and HT-22 cells, white LED light activated mitochondrial cytochrome c oxidase (Cco), in association with enhanced ATP synthase activity and elevated intracellular ATP concentration. Also, reactive oxygen species (ROS) and nitric oxide (NO) production were increased, accompanied by higher calcium concentration and lower mitochondrial membrane potential. HT-22 cells exposed to white LED light for 24h showed reduced viability, with higher apoptotic rate and a cell cycle arrest at G0/G1 phase. Concurrently, the mRNA expression and the concentration of IGF-1 were decreased, while that of TNF-α were increased, in light-exposed cells, which was supported by the luciferase activity of both gene promoters. The down-stream mitogen-activated protein kinase (MAPK), AKT/mTOR pathways were inhibited, in association with an activation of apoptotic caspase 3. N-Acetylcysteine, a ROS scavenger, protected the cells from LED light-induced cellular damage, with rescued cell viability and restored mRNA expression of IGF-1 and TNF-α. Our data demonstrate that white LED light suppresses proliferation and induces apoptosis in hippocampal neuron cells through mitochondrial Cco/ROS-mediated IGF-1 and TNF-α pathways.

Neurosurgical microscopic solid laser-based light inhibits photobleaching during fluorescence-guided brain tumor removal with 5-aminolevulinic acid

BackgroundFluorescence image guided surgery (FIGS) with 5-aminolevulinic acid for malignant gliomas improves surgical outcome. One of the problems during FIGS is photobleaching under surgical microscopic white light. A solid laser-based white light source for neurosurgery that we developed does not include light with a wavelength of around 405nm, which is strongly absorbed by protoporphyrin IX. In the present study, we examined the efficacy of this light source to prevent the photobleaching of protoporphyrin IX-induced fluorescence. MethodsFilter papers transfused with protoporphyrin IX solution and a coronally sectioned F98 glioma rat model pretreated with 50mg/kg 5-aminolevulinic acid were continuously exposed to white light. One group was exposed to conventional xenon-based white light and another group was exposed to laser-based white light. Fluorescence at a wavelength of 635nm was measured with a radiospectrometer (in vitro study) and the relative fluorescence brightness was also measured in digital images (in vivo study) under excitation from violet blue light emitted from diodes every 5min. Results and conclusionEstimated time for 50% photobleaching was prolonged about two times in the laser-based white light exposure group compared with that in the xenon-based white light exposure group (9.1/18.7min). In the brain tumor rat model, it was also prolonged about 2.7 times (15.1/40.7min). A laser-based white light source may inhibit photobleaching during FIGS for malignant gliomas. This light source for neurosurgical microscopy has the potential to prolong the prognosis of malignant glioma patients.

Differential impact in young and older individuals of blue-enriched white light on circadian physiology and alertness during sustained wakefulness

We tested the effect of different lights as a countermeasure against sleep-loss decrements in alertness, melatonin and cortisol profile, skin temperature and wrist motor activity in healthy young and older volunteers under extendend wakefulness. 26 young [mean (SE): 25.0 (0.6) y)] and 12 older participants [(mean (SE): 63.6 (1.3) y)] underwent 40-h of sustained wakefulness during 3 balanced crossover segments, once under dim light (DL: 8 lx), and once under either white light (WL: 250 lx, 2,800 K) or blue-enriched white light (BL: 250 lx, 9,000 K) exposure. Subjective sleepiness, melatonin and cortisol were assessed hourly. Skin temperature and wrist motor activity were continuously recorded. WL and BL induced an alerting response in both the older (p = 0.005) and the young participants (p = 0.021). The evening rise in melatonin was attentuated under both WL and BL only in the young. Cortisol levels were increased and activity levels decreased in the older compared to the young only under BL (p = 0.0003). Compared to the young, both proximal and distal skin temperatures were lower in older participants under all lighting conditions. Thus the color temperature of normal intensity lighting may have differential effects on circadian physiology in young and older individuals.

A Soil-Plate Based Pipeline for Assessing Cereal Root Growth in Response to Polyethylene Glycol (PEG)-Induced Water Deficit Stress.

Drought is a serious problem that causes losses in crop-yield every year, but the mechanisms underlying how roots respond to water deficit are difficult to study under controlled conditions. Methods for assaying root elongation and architecture, especially for seedlings, are commonly achieved on artificial media, such as agar, moistened filter paper, or in hydroponic systems. However, it has been demonstrated that measuring root characteristics under such conditions does not accurately mimic what is observed when plants are grown in soil. Morphological changes in root behavior occur because of differences in solute diffusion, mechanical impedance, exposure to light (in some designs), and gas exchange of roots grown under these conditions. To address such deficiencies, we developed a quantitative method for assaying seedling root lengths and germination in soil using a plate-based approach with wheat as a model crop. We also further developed the method to include defined water deficits stress levels using the osmotic properties of polyethylene glycol (PEG). Seeds were sown into soil-filled vertical plates and grown in the dark. Root length measurements were collected using digital photography through the transparent lid under green lighting to avoid effects of white light exposure on growth. Photographs were analyzed using the cross-platform ImageJ plugin, SmartRoot, which can detect root edges and partially automate root detection for extraction of lengths. This allowed for quick measurements and straightforward and accurate assessments of non-linear roots. Other measurements, such as root width or angle, can also be collected by this method. An R function was developed to collect exported root length data, process and reformat the data, and output plots depicting root/shoot growth dynamics. For water deficit experiments, seedlings were transplanted side-by-side into well-watered plates and plates containing PEG solutions to simulate precise water deficits.

Comprehensive analysis of mouse retinal mononuclear phagocytes.

The innate immune system is activated in a number of degenerative and inflammatory retinal disorders such as age-related macular degeneration (AMD). Retinal microglia, choroidal macrophages, and recruited monocytes, collectively termed 'retinal mononuclear phagocytes', are critical determinants of ocular disease outcome. Many publications have described the presence of these cells in mouse models for retinal disease; however, only limited aspects of their behavior have been uncovered, and these have only been uncovered using a single detection method. The workflow presented here describes a comprehensive analysis strategy that allows characterization of retinal mononuclear phagocytes in vivo and in situ. We present standardized working steps for scanning laser ophthalmoscopy of microglia from MacGreen reporter mice (mice expressing the macrophage colony-stimulating factor receptor GFP transgene throughout the mononuclear phagocyte system), quantitative analysis of Iba1-stained retinal sections and flat mounts, CD11b-based retinal flow cytometry, and qRT-PCR analysis of key microglia markers. The protocol can be completed within 3 d, and we present data from retinas treated with laser-induced choroidal neovascularization (CNV), bright white-light exposure, and Fam161a-associated inherited retinal degeneration. The assays can be applied to any of the existing mouse models for retinal disorders and may be valuable for documenting immune responses in studies for immunomodulatory therapies.

The role of incident light intensity, wavelength, and exposure time in the modification of conjugated polymer structure in solution

Our recent investigations indicate that simple white light exposure holds intriguing potential to alter the structure of conjugated polymer chains. To provide further insight into how to rationally control this process, we have employed small angle neutron scattering to investigate structural changes occurring in solutions of poly(3-hexylthiophene-2,5-diyl) upon exposure to white light. Our previous results indicate significant change in the structure of the polymer upon illumination, an effect we attribute to an alteration in the thermodynamic interactions of the polymer with the surrounding solvent. This work provides additional information to further refine our understanding of this phenomenon by studying the relationship between the magnitude of exciton creation and subsequent structural changes through a series of exposure time, light intensity, and wavelength sensitive experiments. The results demonstrate a clear and consistent relationship between the number of absorbable photons available to the conjugated polymer chain and more powerful alterations in polymer structural parameters, indicating that net exciton generation provides the fundamental driving force for this phenomenon. This points towards the feasibility of employing light exposure protocols as a powerful unobtrusive in-situ method for precise tailoring of optoelectronic active layers over a wide range of organic electronic device fabrication procedures.

Enhanced charge separation at 2D MoS2/ZnS heterojunction: KPFM based study of interface photovoltage

Two dimensional (2D) MoS2/ZnS heterojunctions with MoS2 thickness varying from monolayer to bulk have been prepared by sulfurization of a controlled thickness of Mo deposited on the ZnS thin films. Kelvin probe force microscopy measurements on MoS2/ZnS junction having varying thicknesses of MoS2 layers are carried out in the surface and junction modes, under white light exposure. Differences in the surface potential values of the surface and junction modes represent interface photovoltages at heterojunctions. Enhanced interface photovoltage is observed in junctions having the mono and few layer MoS2 in comparison to bulk MoS2 layer. This suggests the active participation of 2D MoS2 layer in photon absorption and charge separation processes taking place close to the junction. The present study is an effort towards the integration of 2D layered materials with 3D semiconductors, which may be advantageous for the development of 2D material based optoelectronic devices.

Exposing broiler eggs to green, red and white light during incubation

Previous work has shown that exposing broiler eggs to white light during incubation can improve hatchability and post-hatch animal welfare. It was hypothesized that due to how different wavelengths of light can affect avian physiology differently, and how pigmented eggshells filter light that different monochromatic wavelengths would have differential effects on hatchability and post-hatch animal welfare indicators. To determine, we incubated chicken eggs (n=6912) under either no light (dark), green light, red light or white light; the light level was 250 lux. White and red light were observed to increase hatch of fertile (P<0.05) over dark and green light incubated eggs. White, red and green light exposure during incubation improved (P<0.05) the proportion of non-defect chicks over dark incubated eggs. Post-hatch 45-day weight and feed conversion was not affected by light exposure of any wavelength (P>0.05). Fear response of during isolation and tonic immobility was reduced (P<0.05) in broilers incubated under white or red light when compared with either green or dark broilers. Broilers incubated with white or red light had lower (P<0.05) composite asymmetry scores and higher (P<0.05) humoral immunity titers than dark incubated broilers, however, green light broilers did not differ (P>0.05) from dark incubated broilers. All light incubated broilers had lower (P<0.05) plasma corticosterone and higher (P<0.05) plasma serotonin concentrations than dark incubated broilers. These results indicate that white light and red light that is a component of it are possibly the key spectrum to improving hatchability and lower fear and stress susceptibility, whereas green light is not as effective. Incubating broiler eggs under these spectrums could be used to improve hatchery efficiency and post-hatch animal welfare at the same time.

Illumination alters the structure of gels formed from the model optoelectronic material P3HT

Studying the gelation process of conjugated optoelectronic polymers has often been employed as a means of better understanding the final morphology and assembly in active layers of organic electronic devices due to the correlation between the experimentally observed sol-gel transition and many common solution based fabrication techniques. The nature of the percolated network structures formed through the molecular assembly that occurs during this gelation directly affects device performance in conjugated polymer based active layers. Thus, precise knowledge of the evolution of structures during gelation provides crucial information that is needed to rationally improve device performance by directing the assembly during processing. Additionally, observing the effects of environmental factors such as ambient light exposure upon the gelation process will direct efforts towards improving universally overlooked facets of the typical fabrication procedure. Thus, we have conducted a series of ultra small angle and small angle neutron scattering experiments to probe the temperature-driven gelation process of the conjugated photoactive polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) in both the presence and absence of white light. Analysis of the resultant scattering data shows that the gelation process consists of the creation and steady growth of cylindrical aggregates formed by the agglomeration of free chain P3HT. Furthermore, clear differences in the gel structure and assembly between illuminated and non-illuminated gels are observed across multiple length scales, pointing towards an optically-induced variation in the gelation process. Our results indicate that simple white light exposure sharply retards the growth of conjugated polymer microstructures, which clearly suggests that ignoring illumination conditions throughout organic electronic fabrication processes risks producing inconsistent and non-reproducible active layer architectures and ultimately endangers dependable device performance.

Stability-Indicating Related Substances HPLC Method for Droxidopa and Characterization of Related Substances Using LC-MS and NMR.

Stress degradation studies using high-performance liquid chromatography (HPLC) was performed and validated for Droxidopa (L-DOPS). Droxidopa was susceptible to acid hydrolysis (0.1 N HCl), alkaline hydrolysis (0.15 N NaOH) and thermal degradation (105°C). It was found to be resistant to white light, oxidation and UV light exposure (72 h). The thermal, acid and alkali degradation impurities were detected with the retention time (RT) of 12.7, 19.25 and 22.95 min. Our HPLC method detected process impurities (2R,3R)-2-amino-3-(3,4-dihydroxyphenyl)-3-hydroxypropionic acid (Impurity H), N-Hydroxypthalimide (Impurity N), (2R,3S)-2-amino-3-(benzo[d][1,3]dioxol-5-yl)-3-hydroxypropionic acid (Impurity L) and L-threo n-phthaloyl-3-(3, 4-dihydroxyphenyl)-serine (Intermediate) with RTs of 3.48, 15.5, 25.76 and 28.0 min. The related substances were further characterized and confirmed by liquid chromatography-mass spectroscopy (LC-MS), and nuclear magnetic resonance spectroscopy analysis. Our HPLC method detected up to 0.05 µg/mL of Droxidopa with S/N>3.0 and quantified up to 0.10 µg /mL of Droxidopa with S/N ratio>10.0. Droxidopa was highly stable for 12 h after its preparation for HPLC analysis. Our newly developed HPLC method was highly precise, specific, reliable and accurate for the analysis of Droxidopa and its related substances.

Implementation of Actigraphy in Acute Traumatic Brain Injury (TBI) Neurorehabilitation Admissions: A Veterans Administration TBI Model Systems Feasibility Study

BackgroundSleep problems and disorders are prevalent in patients with traumatic brain injury (TBI) and are associated with negative outcomes. Incidence varies because of challenges including differences in assessment methods, particularly in the acute stages of recovery when patients are cognitively impaired and unable to complete traditional self-report methods. Actigraphy (ACG) recently has been validated in the acute TBI rehabilitation setting and may serve as a superior method of assessing sleep-wake patterns at this stage of recovery. Although a few studies with small sample sizes have described the use of ACG, none have described feasibility and implementation protocols. ObjectiveTo describe the feasibility and implementation protocol of ACG to evaluate sleep-wake patterns and white-light exposure data in patients with acute TBI during inpatient rehabilitation. Sleep-wake patterns and light exposure data are presented to characterize the sample using these methods to inform future research. DesignRetrospective study. SettingAcute inpatient rehabilitation unit at a Veterans' Affairs Polytrauma Rehabilitation Center. ParticipantsVeterans (age ≥18 years) admitted to inpatient rehabilitation and enrolled in the Traumatic Brain Injury Model Systems study who were admitted and discharged in the calendar year 2013. MethodsVeterans underwent actigraph watch placement as soon as possible after admission. Records from the calendar year 2013 were reviewed to determine the number of admissions that met study criteria and what percentage of those patients had 3 days of continuous ACG data collected. The barriers to successful watch placement in this population were reviewed. Average sleep, light, and wake data from available records were collected for the study sample. Main Outcome MeasurementsPercentage of patients who met study criteria and who had 72 hours of continuous ACG data collected. The barriers to successful watch placement in this population were reviewed. Average sleep, light, and wake data from available records were collected. ResultsOf 22 eligible Traumatic Brain Injury Model Systems admissions, 3 consecutive nights of ACG data were successfully obtained for 86% (n = 19) of the sample. Barriers to data collection included patient access due to abbreviated lengths of stay, staff availability for ACG placement, and data collection protocols to prevent loss of data in Veterans' Affairs computing systems. ConclusionsACG is feasible for collecting data about sleep, wake, and light exposure in patients who are in acute TBI inpatient rehabilitation settings. Level of EvidenceIII