Boosting 2-photon vision with adaptive optics.

The 2-photon effect in vision occurs when two photons of the same wavelength are absorbed by cone photopigment in the retina and create a visual sensation matching the appearance of light close to half their wavelength. This effect is especially salient for infrared light, where humans are mostly insensitive to 1-photon isomerizations and thus any perception is dominated by 2-photon isomerizations. This phenomenon can be made more readily visible using short-pulsed lasers, which increase the likelihood of 2-photon excitation by making photon arrivals at the retina more concentrated in time. Adaptive optics provides another avenue for enhancing the 2-photon effect by focusing light more tightly at the retina, thereby increasing the spatial concentration of incident photons. This article makes three contributions. First, we demonstrate through color-matching experiments that an adaptive optics correction can provide a 25-fold increase in the luminance of the 2-photon effect-a boost equivalent to reducing pulse width by 96%. Second, we provide image-based evidence that the 2-photon effect occurs at the photoreceptor level. Third, we use our results to compute the specifications for a system that could utilize 2-photon vision and adaptive optics to image and stimulate the retina using a single infrared wavelength and reach luminance levels comparable to conventional displays.

Association Between Pediatric Delirium and Quality of Life After Discharge.

OBJECTIVE: Delirium occurs frequently in critically ill children, with highest rates reported in children under 5 years old. The objective of this study was to measure the residual effect of delirium on quality of life at 1 and 3 months after hospital discharge. DESIGN: Prospective observational cohort study. SETTING: Urban academic PICU. PATIENTS: Children younger than five years of age at time of admission to the PICU. INTERVENTIONS: All children were screened for delirium (using the Cornell Assessment for Pediatric Delirium) throughout their stay in the PICU. Quality of life was measured using the Infant-Toddler Quality of Life questionnaire at three time points: baseline, 1 month, and 3 months after hospital discharge. Infant-Toddler Quality of Life scores were compared between children who did and did not develop delirium. MEASUREMENTS AND MAIN RESULTS: Two hundred seven children were enrolled. One hundred twenty-two completed the 1-month follow-up, and 117 completed the 3-month follow-up. Fifty-six children (27%) developed delirium during their PICU stay. At follow-up, Infant-Toddler Quality of Life scores for the PICU cohort overall were consistently lower than age-related norms. When analyzed by delirium status, children who had experienced delirium scored lower in every quality of life domain when compared with children who did not experience delirium. Even after controlling for severity of illness, delirious patients demonstrated an average 11-point lower general health score than nondelirious patients (p = 0.029). CONCLUSION: This pilot study shows an independent association between delirium and decreased quality of life after hospital discharge in young children.

A conserved retromer-independent function for RAB-6.2 in C. elegans epidermis integrity.

Rab proteins are conserved small GTPases that coordinate intracellular trafficking essential to cellular function and homeostasis. RAB-6.2 is a highly conserved C. elegans ortholog of human RAB6 proteins. RAB-6.2 is expressed in most tissues in C. elegans and is known to function in neurons and in the intestine to mediate retrograde trafficking. Here, we show that RAB-6.2 is necessary for cuticle integrity and impermeability in C. elegans RAB-6.2 functions in the epidermis to instruct skin integrity. Significantly, we show that expression of a mouse RAB6A cDNA can rescue defects in C. elegans epidermis caused by lack of RAB-6.2, suggesting functional conservation across phyla. We also show that the novel function of RAB-6.2 in C. elegans cuticle development is distinct from its previously described function in neurons. Exocyst mutants partially phenocopy rab-6.2-null animals, and rab-6.2-null animals phenocopy mutants that have defective surface glycosylation. These results suggest that RAB-6.2 may mediate the trafficking of one or many secreted glycosylated cuticle proteins directly, or might act indirectly by trafficking glycosylation enzymes to their correct intracellular localization.

Delirium in Critically Ill Children: An International Point Prevalence Study.

OBJECTIVES: To determine prevalence of delirium in critically ill children and explore associated risk factors. DESIGN: Multi-institutional point prevalence study. SETTING: Twenty-five pediatric critical care units in the United States, the Netherlands, New Zealand, Australia, and Saudi Arabia. PATIENTS: All children admitted to the pediatric critical care units on designated study days (n = 994). INTERVENTION: Children were screened for delirium using the Cornell Assessment of Pediatric Delirium by the bedside nurse. Demographic and treatment-related variables were collected. MEASUREMENTS AND MAIN RESULTS: Primary study outcome measure was prevalence of delirium. In 159 children, a final determination of mental status could not be ascertained. Of the 835 remaining subjects, 25% screened positive for delirium, 13% were classified as comatose, and 62% were delirium-free and coma-free. Delirium prevalence rates varied significantly with reason for ICU admission, with highest delirium rates found in children admitted with an infectious or inflammatory disorder. For children who were in the PICU for 6 or more days, delirium prevalence rate was 38%. In a multivariate model, risk factors independently associated with development of delirium included age less than 2 years, mechanical ventilation, benzodiazepines, narcotics, use of physical restraints, and exposure to vasopressors and antiepileptics. CONCLUSIONS: Delirium is a prevalent complication of critical illness in children, with identifiable risk factors. Further multi-institutional, longitudinal studies are required to investigate effect of delirium on long-term outcomes and possible preventive and treatment measures. Universal delirium screening is practical and can be implemented in pediatric critical care units.

Novice research: central venous access device care infections.

This article describes a literature review of published evidence on infection prevention and control in central venous access device (CVAD) care conducted by a novice researcher (lead author) under the supervision of her lecturer (second author). It includes details of the search as well as of the analysis which led to the selection and critical appraisal of a selected article identified and, importantly, discussion of the limitations and lessons learned by the novice researcher with her experimental approach. Infection control is paramount within nursing practice as a result of the number of healthcare-associated infections, which are preventable if evidence-based practice is followed and when trust protocols are informed by evidence. The question posed by the author prior to undertaking the literature search related to whether the use of sterile gloves for CVADs reduces infections in the oncology patient population compared with the use of non-sterile gloves. The question was formulated using the PICO (Population, Intervention, Comparison, Outcome) process and relevant literature was located using CINAHL and MEDLINE databases. The results of the review demonstrated no significant difference in infection rates using sterile or non-sterile gloves when handling CVADs but further research in this area is needed to validate the findings.