Foveal Retinal Ganglion Cells Develop Altered Calcium Dynamics Weeks After Photoreceptor Ablation.

Purpose: Physiological changes in retinal ganglion cells (RGCs) have been reported in rodent models of photoreceptor (PR) loss, but this has not been investigated in primates. By expressing both a calcium indicator (GCaMP6s) and an optogenetic actuator (ChrimsonR) in foveal RGCs of the macaque, we reactivated RGCs in vivo and assessed their response in the weeks and years after PR loss. Design: We used an in vivo calcium imaging approach to record optogenetically evoked activity in deafferented RGCs in primate fovea. Cellular scale recordings were made longitudinally over a 10-week period after PR ablation and compared with responses from RGCs that had lost PR input >2 years prior. Participants: Three eyes received PR ablation, the right eye of a male Macaca mulatta (M1), the left eye of a female Macaca fascicularis (M2), and the right eye of a male Macaca fascicularis (M3). Two animals were used for in vivo recording, 1 for histological assessment. Methods: Cones were ablated with an ultrafast laser delivered through an adaptive optics scanning light ophthalmoscope (AOSLO). A 0.5 second pulse of 25 Hz 660 nm light optogenetically stimulated RGCs, and the resulting GCaMP fluorescence signal was recorded using an AOSLO. Measurements were repeated over 10 weeks immediately after PR ablation, at 2.3 years and in control RGCs. Main Outcome Measures: The calcium rise time, decay constant, and sensitivity index of optogenetic-mediated RGC were derived from GCaMP fluorescence recordings from 221 RGCs (animal M1) and 218 RGCs (animal M2) in vivo. Results: After PR ablation, the mean decay constant of the calcium response in RGCs decreased 1.5-fold (standard deviation 1.6 ± 0.5 seconds to 0.6 ± 0.3 seconds) over the 10-week observation period in subject 1 and 2.1-fold (standard deviation 2.5 ± 0.5 seconds to 1.2 ± 0.2 seconds) within 8 weeks in subject 2. Calcium rise time and sensitivity index were stable. Optogenetic reactivation remained possible 2.3 years after PR ablation. Conclusions: Altered calcium dynamics developed in primate foveal RGCs in the weeks after PR ablation. The mean decay constant of optogenetic-mediated calcium responses decreased 1.5- to twofold. This is the first report of this phenomenon in primate retina and further work is required to understand the role these changes play in cell survival and activity. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Problem-based learning curriculum disconnect on diversity, equitable representation, and inclusion.

Diversity, equity, and inclusion (DEI) mission statements continue to be adopted by academic institutions in general, and by dental schools around the globe in particular. But DEI content seems to be under-developed in dental education. The objectives of this study were two-fold: to extract information from all the PBL cases at University of British Columbia's Faculty of Dentistry curriculum in terms of the diversity, equitable representation, and inclusion of patient and provider characteristics, context, and treatment outcomes; and; to compare these findings with the composition of the British Columbia census population, dental practice contextual factors, and the evidence on treatment outcomes within patient care. Information from all the 58 PBL cases was extracted between January and March 2023, focusing on patient and provider characteristics (e.g., age, gender, ethnicity), context (e.g., type of insurance), and treatment outcomes (e.g., successful/unsuccessful). This information was compared with the available literature. From all the 58 PBL cases, 0.4% included non-straight patients, while at least 4% of BC residents self-identify as non-straight; there were no cases involving First Nations patients although they make up 6% of the British Columbia population. Less than 10% of the cases involved older adults who make up almost 20% of the population. Only Treatments involving patients without a disability were 5.74 times more likely to be successful compared to those involving patients with a disability (p<0.05). The characteristics of the patients, practice context, and treatment outcomes portrayed in the existing PBL cases seem to differ from what is known about the composition of the British Columbia population, treatment outcome success, and practice context; a curriculum disconnect seems to exist. The PBL cases should be revised to better represent the population within which most students will practice.

Finite element analysis of kangaroo astragali: A new angle on the ankle.

Using finite element analysis on the astragali of five macropodine kangaroos (extant and extinct hoppers) and three sthenurine kangaroos (extinct proposed bipedal striders) we investigate how the stresses experienced by the ankle in similarly sized kangaroos of different hypothesized/known locomotor strategy compare under different simulation scenarios, intended to represent the moment of midstance at different gaits. These tests showed a clear difference between the performance of sthenurines and macropodines with the former group experiencing lower stress in simulated bipedal strides in all species compared with hopping simulations, supporting the hypothesis that sthenurines may have utilized this gait. The Pleistocene macropodine Protemnodon also performed differently from all other species studied, showing high stresses in all simulations except for bounding. This may support the hypothesis of Protemnodon being a quadrupedal bounder.

Linking Cognitive Integrity to Working Memory Dynamics in the Aging Human Brain.

Aging is accompanied by a decline of working memory, an important cognitive capacity that involves stimulus-selective neural activity that persists after stimulus presentation. Here, we unraveled working memory dynamics in older human adults (male and female) including those diagnosed with mild cognitive impairment (MCI) using a combination of behavioral modeling, neuropsychological assessment, and MEG recordings of brain activity. Younger adults (male and female) were studied with behavioral modeling only. Participants performed a visuospatial delayed match-to-sample task under systematic manipulation of the delay and distance between sample and test stimuli. Their behavior (match/nonmatch decisions) was fit with a computational model permitting the dissociation of noise in the internal operations underlying the working memory performance from a strategic decision threshold. Task accuracy decreased with delay duration and sample/test proximity. When sample/test distances were small, older adults committed more false alarms than younger adults. The computational model explained the participants' behavior well. The model parameters reflecting internal noise (not decision threshold) correlated with the precision of stimulus-selective cortical activity measured with MEG during the delay interval. The model uncovered an increase specifically in working memory noise in older compared with younger participants. Furthermore, in the MCI group, but not in the older healthy controls, internal noise correlated with the participants' clinically assessed cognitive integrity. Our results are consistent with the idea that the stability of working memory contents deteriorates in aging, in a manner that is specifically linked to the overall cognitive integrity of individuals diagnosed with MCI.

Foveal RGCs develop altered calcium dynamics weeks after photoreceptor ablation.

Objective or purpose: Physiological changes in retinal ganglion cells (RGCs) have been reported in rodent models of photoreceptor (PR) loss but this has not been investigated in primates. By expressing both a calcium indicator (GCaMP6s) and an optogenetic actuator (ChrimsonR) in foveal RGCs of the macaque, we reactivated RGCs in vivo and assessed their response in the weeks and years following PR loss. Design: We used an in vivo calcium imaging approach to record optogenetically evoked activity in deafferented RGCs in primate fovea. Cellular scale recordings were made longitudinally over a 10 week period following photoreceptor ablation and compared to responses from RGCs that had lost photoreceptor input more than two years prior. Participants: Three eyes received photoreceptor ablation, OD of a male Macaca mulatta (M1), OS of a female Macaca fascicularis (M2) and OD of a male Macaca fascicularis (M3). Two animals were used for in vivo recording, one for histological assessment. Methods: Cones were ablated with an ultrafast laser delivered through an adaptive optics scanning light ophthalmoscope (AOSLO). A 0.5 s pulse of 25Hz 660nm light optogenetically stimulated RGCs, and the resulting GCaMP fluorescence signal was recorded using AOSLO. Measurements were repeated over 10 weeks immediately after PR ablation, at 2.3 years and in control RGCs. Main Outcome measures: The calcium rise time, decay constant and sensitivity index of optogenetic mediated RGC were derived from GCaMP fluorescence recordings from 221 RGCs (Animal M1) and 218 RGCs (Animal M2) in vivo. Results: Following photoreceptor ablation, the mean decay constant of the calcium response in RGCs decreased 1.5 fold (1.6±0.5 s to 0.6±0.3 s SD) over the 10 week observation period in subject 1 and 2.1 fold (2.5±0.5 s to 1.2±0.2 s SD) within 8 weeks in subject 2. Calcium rise time and sensitivity index were stable. Optogenetic reactivation remained possible 2.3 years after PR ablation. Conclusions: Altered calcium dynamics developed in primate foveal RGCs in the weeks after photoreceptor ablation. The mean decay constant of optogenetic mediated calcium responses decreased 1.5 - 2-fold. This is the first report of this phenomenon in primate retina and further work is required to understand the role these changes play in cell survival and activity.

Restless legs syndrome is prevalent in adults with cystic fibrosis and impacts sleep quality.

BACKGROUND: Restless legs syndrome (RLS) is a sensorimotor disorder that is prevalent in chronic inflammatory conditions. RLS prevalence, risk factors, and impact on sleep in CF have not been extensively characterized to date. METHODS: An initial cohort was examined, including 75 persons with CF (PwCF) and 75 control subjects, to look at the prevalence and severity of RLS. A second validation cohort of 191 PwCF was then enrolled from two CF centers to examine risk factors for RLS. A diagnosis of RLS was made according to the International RLS Study Group (IRLSSG) criteria. Sleep quality was identified using the Pittsburgh sleep quality index (PSQI). Epworth sleepiness scale (ESS) was used to measure daytime sleepiness. We then analyzed laboratory and clinical risk factors and sleep symptoms for potential risk factors for RLS. RESULTS: In the initial cohort, 36 % of PwCF had RLS, and 9 % of these had significant RLS. In contrast, only 15 % of controls had RLS, and none had significant RLS. In the second larger validation cohort with 191 subjects, a comparable prevalence of RLS was identified. Higher hemoglobin A1c, use of SSRI/SNRI medications, worse PSQI and ESS sleep quality scores, lower lung function, and higher antibiotic usage were significantly associated with a diagnosis of RLS. By multivariate multinominal logistic regression analysis, higher HbA1c and worse PSQI global sleep quality scores were independent predictors of significant RLS. CONCLUSIONS: RLS is highly prevalent in CF. Higher HbA1c and poor sleep quality, signified by higher PSQI, were each independent predictors of RLS.

Appropriate Categorization of Inequality to Inform Policy Decisions: Estimating Distribution of Lifetime Health Using Alternative Approaches to Socioeconomic Stratification.

OBJECTIVES: Estimation of gradients in lifetime health, notably quality-adjusted life expectancy (QALE), has largely focused on index of multiple deprivation to categorize the population by socioeconomic position. In this article, we estimate QALE using alternate, individual- rather than area-level, indicators of socioeconomic position. METHODS: Building on previous research methods, the distribution of QALE is estimated across education and income groups based on data from the Health Survey for England and the Office for National Statistics. QALE is estimated for each group by combining multivariate mortality rates and health-related quality of life (HRQL) weights using life tables. HRQL weights were estimated using ordinary least squares and missing data were handled using multiple imputation. RESULTS: The estimated lifetime HRQL weights decreased with increased age, lower educational attainment, and lower income. For example, the QALE at birth for males in the lowest educational attainment group was 61.69 quality-adjusted life-years (QALYs), 1.54 QALYs lower than females in the same group. This is in contrast to 76.58 and 75.89 QALYs for males and females in the highest educational attainment group, respectively. A similar trend was observed across income quintiles albeit the gap was less pronounced. CONCLUSIONS: The use of index of multiple deprivation to assess health inequalities may be masking important information about individual-level variation. Decisions makers should consider this alongside the merits of using area-level approaches to categorizing the population if individual-level approaches are preferable.

Imaging incidence and type in primary care patients with low back pain: a cross-sectional study on new referrals to an Australian specialist spinal surgical centre.

Introduction Low back pain (LBP) is common and a significant cause of morbidity. Many patients receive inappropriate imaging for LBP in primary care. Aim To explore the incidence and type of spinal imaging conducted for LBP patients referred from general practice for specialist surgical opinion, and evaluate whether imaging conformed to clinical guidelines. Methods Audit of a sequential cohort (n = 100) of new LBP patients referred from primary care for specialist opinion at a suburban Australian capital city independent Spinal Centre. Results In the 6 months before referral, 90% (95% CI 83-95%) of patients underwent spinal imaging. Imaging was performed in 95% of those who did and 79% of those who did not meet guidelines for radiological investigation. 35% of patients were inappropriately imaged and 3% inappropriately not imaged. Spinal computed tomography (CT) imaging was used in 52% of patients, magnetic resonance imaging (MRI) in 42% and image-guided lumbar spinal interventional procedures in 28%. Discussion Most patients with LBP referred for surgical opinion have diagnostic radiological investigations whether or not it is indicated by clinical guidelines. The more frequent use of spinal CT compared to MRI may be due to idiosyncrasies of the Australian Medicare Benefits Schedule (MBS) rebate system. The findings of this pilot study provide support for the changes recommended by the 2016 MBS Review Taskforce on LBP that permit GP access to subsidised lumbar MRI, while constraining access to lumbar CT, and provide novel data about spinal imaging and practice in this cohort of patients.

Optogenetic Stimulation of Single Ganglion Cells in the Living Primate Fovea.

Though the responses of the rich variety of retinal ganglion cells (RGCs) reflect the totality of visual processing in the retina and provide the sole conduit for those processed responses to the brain, we have much to learn about how the brain uses these signals to guide behavior. An impediment to developing a comprehensive understanding of the role of retinal circuits in behavior is the paucity of causal studies in the intact primate visual system. Here we demonstrate the ability to optogenetically activate individual RGCs with flashes of light focused on single RGC somas in vivo , without activation of neighboring cells. The ability to selectively activate specific cells is the first step toward causal experiments that directly link retinal circuits to visual experience and behavior.

A six-year teaching life supportive first aid program to eventually generate peer trainer pupils: a prospective case control study.

BACKGROUND: Out of hospital cardiac arrest is a life-threatening condition. To improve the chances of survival, lay-person cardio-pulmonary-resuscitation (CPR) is a crucial factor. Many bystanders fail to react appropriately, even if life supporting first aid (LSFA) programs and campaigns including CPR tried to increase the handling of basic cardiac life support. To achieve an enhanced learning of CPR a pupil's grade after grade teaching program was established in a school with medical students. METHODS: The learning of CPR was investigated in a prospective, case-controlled study at an international school. Pupils (12 ± 3 years old) joining our LSFA courses (n = 538, female: 243, attendance for evaluation: 476) were compared to a control group (n = 129, female: 52, attendance for evaluation: 102). Surveys and quality of CPR (QCPR%) through a computer linked "Resusci Anne" dummy were compared with Chi-squared tests, t-tests pair wisely, and by one-way ANOVA. RESULTS: Knowledge and skills on the "Resusci Anne" were significantly better in trained grade 9 pupils compared to the control group (QCPR, 59 vs. 25%). The number of LSFA courses each grade 9 student had, correlated with improved practical performance (r2 = 0.21, p < 0.001). The willingness to deliver CPR to strangers increased with improved practical performance. Attitudes towards performing CPR were high in all participating grades. CONCLUSION: Repetitive teaching LSFA to grade 5-9 pupil's grade after grade by medical students has been successfully established. Pupils who finish the program will eventually be able to teach LSFA to younger students. This is furthermore a good way of sharing a "learning by teaching" role and it enables to have more pupils as trainers who can provide instruction to a larger number of pupils with the purpose of having a better-trained population in LSFA.

Effects of Secondary Dopant Anions on Emissivity and Related Properties of Poly(3,4-ethylenedioxythiophene).

Smart materials that are energy efficient and take up less space are crucial in the development of new technologies. Electrochromic polymers (ECPs) are one such class of materials that actively change their optical behavior in both visible and infrared parts of the electromagnetic spectrum. They show promise in a wide range of applications, from active camouflage to smart displays/windows. The full capabilities of ECPs are still yet to be explored, for while their electrochromic properties are well established, their Infrared (IR) modulation is less reported on. This study addresses the potential of ECPs in active IR modulating devices by optimization of Vapor Phase Polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) thin films via the substitution of its dopant anion. Dynamic ranges denoting emissivity changes between reduced and oxidized states of PEDOT are found across dopants of tosylate, bromide, sulfate, chloride, perchlorate, and nitrate. Relative to the emissivity of reduced (neutral) PEDOT, a range of ±15% is achieved from the doped PEDOT films, and a maximum dynamic range of 0.11 across a 34% change is recorded for PEDOT doped with perchlorate.

Short bursts of transcutaneous auricular vagus nerve stimulation enhance evoked pupil dilation as a function of stimulation parameters.

Transcutaneous auricular vagus nerve stimulation (taVNS) is a neurostimulatory technique hypothesised to enhance central noradrenaline. Currently, there is scarce evidence in support of a noradrenergic mechanism of taVNS and limited knowledge on its stimulation parameters (i.e., intensity and pulse width). Therefore, the present study aimed to test whether taVNS enhances pupil dilation, a noradrenergic biomarker, as a function of stimulation parameters. Forty-nine participants received sham (i.e., left ear earlobe) and taVNS (i.e., left ear cymba concha) stimulation in two separate sessions, in a counterbalanced order. We administered short bursts (5s) of seven stimulation settings varying as a function of pulse width and intensity and measured pupil size in parallel. Each stimulation setting was administered sixteen times in separate blocks. We expected short bursts of stimulation to elicit phasic noradrenergic activity as indexed by event-related pupil dilation and event-related temporal derivative. We hypothesised higher stimulation settings, quantified as the total charge per pulse (pulse width x intensity), to drive greater event-related pupil dilation and temporal derivative in the taVNS compared to sham condition. Specifically, we expected stimulation settings in the taVNS condition to be associated with a linear increase in event-related pupil dilation and temporal derivative. We found stimulation settings to linearly increase both pupil measures. In line with our hypothesis, the observed dose-dependent effect was stronger in the taVNS condition. We also found taVNS to elicit more intense and unpleasant sensations than sham stimulation. These results support the hypothesis of a noradrenergic mechanism of taVNS. However, future studies should disentangle whether stimulation elicited sensations mediate the effect of taVNS on evoked pupil dilation.

Using general practitioners with an extended role in spinal practice for the initial assessment of patients referred to spinal surgeons: preliminary experience and challenges.

AIM: To describe experience using general practitioners (GPs), with an extended role (GPwER) in spinal medicine, to expedite assessment, triage, and management of patients referred from primary care for specialist spinal surgical opinion. BACKGROUND: Low back and neck pain are common conditions in primary care. Indiscriminate or inappropriate referral to a spinal surgeon contributes to long waiting times. Previous attempts at triaging patients who really require a surgical opinion have used practice nurses, physiotherapists, clinical algorithms, and interdisciplinary screening clinics. METHODS: Within the setting of an independent spinal care centre, we have used GPs specially trained in spinal practice to expedite the assessment and triage of new referrals between 2015 and 2021. We reviewed feedback from a Patient Satisfaction Questionnaire and the postgraduate backgrounds, training, practice with regard to triage of new referrals, and experiences of the GPs who were recruited. FINDINGS: Six GPwER had a mean of 26 years of postgraduate experience before appointment (range 10-44 years). The first four GPwER, appointed between 2015 and 2018, underwent an ad hoc in-house, interdisciplinary training programme and saw 2994 new patients between 2016 and 2020. After GPwER, assessment in only 18.9% (range 12.6 to 22.7%) of these patients was a spinal surgical opinion deemed necessary. Waiting times to see the spinal surgeon remained at 6-8 weeks despite a three-fold annual increase (from 340 to 1058) in new referrals. A Patient Satisfaction Questionnaire revealed high levels of satisfaction with the performances of the GPwER across seven dimensions. A dedicated training programme was designed in 2020, and the last two appointees underwent 20 h of clinical teaching prior to practice. Initial experience using GPwER, here termed 'Spinal Clinicians', suggests they are efficient at screening for patients needing spinal surgical referral. Establishing a recognised training programme, assessment, and certification for these practitioners are the next challenges.

Methods of assessing value for money of UK-based early childhood public health interventions: a systematic literature review.

INTRODUCTION: Economic evaluation has an important role to play in the demonstration of value for money of early childhood public health interventions; however, concerns have been raised regarding their consistent application and relevance to commissioners. This systematic review of the literature therefore aims to collate the breadth of the existing economic evaluation evidence of these interventions and to identify the approaches adopted in the assessment of value. SOURCE OF DATA: Recently published literature in Medline, EMBASE, EconLit, Health Management Information Consortium, Cochrane CENTRAL, Cochrane Database of Systematic Reviews, Health Technology Assessment, NHS EED and Web of Science. AREAS OF AGREEMENT: The importance of the early childhood period on future health and well-being as well as the potential to impact health inequalities making for a strong narrative case for expenditure in early childhood public health. AREAS OF CONTROVERSY: The most appropriate approaches to evaluating value for money of such preventative interventions relevant for UK decision-makers given the evident challenges. GROWING POINTS: The presented review considered inconsistencies across methodological approaches used to demonstrate value for money. The results showed a mixed picture in terms of demonstrating value for money. AREAS TIMELY FOR DEVELOPING RESEARCH: Future resource allocations decisions regarding early childhood public health interventions may benefit from consistency in the evaluative frameworks and health outcomes captured, as well as consistency in approaches to incorporating non-health costs and outcomes, incorporating equity concerns and the use of appropriate time horizons.

Flexible sensory-motor mapping rules manifest in correlated variability of stimulus and action codes across the brain.

Humans and non-human primates can flexibly switch between different arbitrary mappings from sensation to action to solve a cognitive task. It has remained unknown how the brain implements such flexible sensory-motor mapping rules. Here, we uncovered a dynamic reconfiguration of task-specific correlated variability between sensory and motor brain regions. Human participants switched between two rules for reporting visual orientation judgments during fMRI recordings. Rule switches were either signaled explicitly or inferred by the participants from ambiguous cues. We used behavioral modeling to reconstruct the time course of their belief about the active rule. In both contexts, the patterns of correlations between ongoing fluctuations in stimulus- and action-selective activity across visual- and action-related brain regions tracked participants' belief about the active rule. The rule-specific correlation patterns broke down around the time of behavioral errors. We conclude that internal beliefs about task state are instantiated in brain-wide, selective patterns of correlated variability.

Time estimation and arousal responses in dopa-responsive dystonia.

Dopa-responsive dystonia (DRD) is caused by an impaired dopamine biosynthesis due to a GTP-cyclohydrolase-1 (GCH1) deficiency, resulting in a combination of dystonia and parkinsonism. However, the effect of GCH1 mutations and levodopa treatment on motor control beyond simple movements, such as timing, action preparation and feedback processing, have not been investigated so far. In an active time estimation task with trial-by-trial feedback, participants indicated a target interval (1200 ms) by a motor response. We compared 12 patients tested (in fixed order) under their current levodopa medication ("ON") and after levodopa withdrawal ("OFF") to matched healthy controls (HC), measured twice to control for repetition effects. We assessed time estimation accuracy, trial-to-trial adjustment, as well as task- and feedback-related pupil-linked arousal responses. Patients showed comparable time estimation accuracy ON medication as HC but reduced performance OFF medication. Task-related pupil responses showed the reverse pattern. Trial-to-trial adjustments of response times were reduced in DRD, particularly OFF medication. Our results indicate differential alterations of time estimation accuracy and task-related arousal dynamics in DRD patients as a function of dopaminergic medication state. A medication-independent alteration of task repetition effects in DRD cannot be ruled out with certainty but is discussed as less likely.

Appraising the Costs of Genomic Testing for Histology-Independent Technologies: An Illustrative Example for NTRK Fusions.

OBJECTIVES: Histology-independent (HI) technologies are authorized for patients with advanced or metastatic cancer if they express a particular biomarker regardless of its position in the body. Although this represents an important advancement in cancer treatment, genomic testing to identify eligible individuals for HI technologies will require substantial investment and impact their cost-effectiveness. Estimating these costs is complicated by several issues, which affect not only the overall cost of testing but also the distribution of testing costs across tumor types. METHODS: Key issues that should be considered when evaluating the cost of genomic testing to identify those eligible for HI technologies are discussed. These issues are explored in illustrative analyses where costs of genomic testing for NTRK fusions in England for recently approved HI technologies are estimated. RESULTS: The prevalence of mutation, testing strategy adopted, and current testing provision affect the cost of identifying eligible patients. The illustrative analysis estimated the cost of RNA-based next-generation sequencing to identify 1 individual with an NTRK fusion ranged between £377 and £282 258. To improve cost-effectiveness, testing costs could be shared across multiple technologies. An estimated additional ∼4000 patients would need to be treated with other HI therapies for testing in patients with advanced or metastatic cancer to be cost-effective. CONCLUSIONS: The cost of testing to identify individuals eligible for HI technologies affect the drug's cost-effectiveness. The cost of testing across tumor types varies owing to heterogeneity in the mutation's prevalence and current testing provision. The cost-effectiveness of HI technologies may be improved if testing costs could be shared across multiple agents.

Methods to Identify Immune Cells in Tissues With a Focus on Skin as a Model.

The skin protects our body from external challenges, insults, and pathogens and consists of two layers, epidermis and dermis. The immune cells of the skin are an integral part of protecting the body and essential for mediating skin immune homeostasis. They are distributed in the epidermal and dermal layers of the skin. Under homeostatic conditions, the mouse and human skin epidermis harbors immune cells such as Langerhans cells and CD8+ T cells, whereas the dermis contains dendritic cells (DCs), mast cells, macrophages, T cells, and neutrophils. Skin immune homeostasis is maintained through communication between epidermal and dermal cells and soluble factors. This communication is important for proper recruitment of immune cells in the skin to mount immune responses during infection/injury or in response to external/internal insults that alter the local cellular milieu. Imbalance in this crosstalk that occurs in association with inflammatory skin disorders such as psoriasis and atopic dermatitis can lead to alterations in the number and type of immune cells contributing to pathological manifestation in these disorders. Profiling changes in the immune cell type, localization, and number can provide important information about disease mechanisms and help design interventional therapeutic strategies. Toward this end, skin cells can be detected and characterized using basic techniques like immunofluorescence, immunohistochemistry, and flow cytometry, and recently developed methods of multiplexing. This article provides an overview on the basic techniques that are widely accessible to researchers to characterize immune cells of the skin. © 2022 The Authors. Current Protocols published by Wiley Periodicals LLC.

Modified fluid gelatin 4% for perioperative volume replacement in pediatric patients (GPS): Results of a European prospective noninterventional multicenter study.

INTRODUCTION: Modified fluid gelatin 4% is approved for use in children, but there is still a surprising lack of clinical studies including large numbers of pediatric patients. Therefore, we performed a European prospective noninterventional multicenter study to evaluate the use of a modified fluid gelatin 4% in saline (sal-GEL) or an acetate-containing balanced electrolyte solution (bal-GEL) in children undergoing major pediatric surgery. AIMS: The primary aim was to assess the indications and dosing of modified fluid gelatin, and the secondary aim was to assess the safety and efficacy, focusing, in particular, on routinely collected clinical parameters. METHODS: Children aged up to 12 years with ASA risk scores of I-III receiving sal-GEL or bal-GEL were followed perioperatively. Demographic data, surgical procedures performed, anesthesia, hemodynamic and laboratory data, adverse events, and adverse drug reactions were documented using a standardized case report form. RESULTS: 601 children that were investigated at 13 European pediatric centers from May 2015 to March 2020 (sal-GEL 20.1%, bal-GEL 79.9%; mean age 29.1 ± 38.6 (range 0-144) months; body weight 12.1 ± 10.5 (1.4-70) kg) were included in the analysis. The most frequent indications for GEL infusion were hemodynamic instability without bleeding (76.0%), crystalloids alone not being sufficient for hemodynamic stabilization (55.7%), replacement of preoperative deficit (26.0%), and significant bleeding (13.0%). Mean infused GEL volume was 13.0 ± 5.3 (2.4-37.5) ml kg-1 . The total dose was affected by age, with higher doses in younger patients. After gelatin infusion, mean arterial pressure increased (mean change 8.5 ± 7.3 [95% CI: 8 to 9.1] mmHg), and the hemoglobin concentrations decreased significantly (mean change -1.1 ± 1.8 [95% CI: -1.2 to -0.9] g·dL-1 ). Acid-base parameters were more stable with bal-GEL. No serious adverse drug reactions directly related to gelatin (i.e., anaphylactoid reaction, clotting disorders, and renal failure) were observed. CONCLUSION: Moderate doses up to 20 ml kg-1 of modified fluid gelatin were infused most frequently to improve hemodynamic stability in children undergoing major pediatric surgery. The acid-base balance was more stable when gelatin in a balanced electrolyte solution was used instead of saline. No serious adverse drug reactions associated with gelatin were observed.

Fifteen-minute consultation: Intubation of the critically ill child presenting to the emergency department.

Intubation of critically ill children presenting to the emergency department is a high-risk procedure. Our article aims to offer a step-by-step guide as to how to plan and execute a rapid, successful intubation in a way that minimises risk of adverse events and patient harm. We address considerations such as the need for adequate resuscitation before intubation and selection of equipment and personnel. We also discuss drug choice for induction and peri-intubation instability, difficult airway considerations as well as postintubation care. Focus is also given on the value of preintubation checklists, both in terms of equipment selection and in the context of staff role designation and intubation plan clarity. Finally, in cases of failed intubation, we recommend the application of the Vortex approach, highlighting, thus, the importance of avoiding task fixation and maintaining our focus on what matters most: adequate oxygenation.