Histological and molecular characterization of the growing nasal septum in mice.

The nasal septum is a cartilaginous structure that serves as a pacemaker for the development of the midface. The septum is a hyaline cartilage which is surrounded by a perichondrium and epithelium. It remains cartilaginous anteriorly, but posteriorly it undergoes endochondral ossification to form the perpendicular plate of the ethmoid. Understanding of hyaline cartilage differentiation stems predominantly from investigations of growth plate cartilage. It is currently unclear if the morphological and molecular properties of the differentiating nasal septum align with what is known from the growth plate. In this study, we describe growth, molecular, and cellular characteristics of the nasal septum with reference to hyaline cartilage differentiation. The nasal septum grows asynchronous across its length with phases of rapid growth interrupted by more stagnant growth. Growth appears to be driven predominantly by acquisition of chondrocyte hypertrophy. Similarly, cellular differentiation is asynchronous, and differentiation observed in the anterior part precedes posterior differentiation. Overall, the nasal septum is structurally and molecularly heterogeneous. Early and extensive chondrocyte hypertrophy but no ossification is observed in the anterior septum. Onset of hypertrophic chondrocyte differentiation coincided with collagen fiber deposition along the perichondrium. Sox9, Col2, Col10, Mmp13, Sp7, and Runx2 expression was heterogeneous and did not always follow the expected pattern established from chondrocyte differentiation in the growth plate. The presence of hypertrophic chondrocytes expressing bone-related proteins early on in regions where the nasal septum does not ossify displays incongruities with current understanding of hyaline cartilage differentiation. Runx2, Collagen II, Collagen X, and Sp7 commonly used to mark distinct stages of chondrocyte maturation and early bone formation show wider expression than expected and do not align with expected cellular characteristics. Thus, the hyaline cartilage of the nasal septum is quite distinct from growth plate hyaline cartilage, and caution should be taken before assigning cartilage properties to less well-defined cartilage structures using these commonly used markers. Beyond the structural description of the nasal cartilage, this study also provides important information for cartilage tissue engineering when using nasal septal cartilage for tissue regeneration.

Improving Satisfaction with Pediatric Pain Management by Inviting the Conversation.

BACKGROUND: Patient satisfaction with pain management is associated with improved patient adherence to medical management and efficient service utilization. Pediatric pain control is challenging, given the inability to elicit reliable histories, particularly in younger patients. Several studies have suggested that communication surrounding pain management can improve satisfaction, although there are limited data describing structured interventions with measurable outcomes. A quality improvement project was conducted to determine if reliably asking families about pain management was associated with improved patient satisfaction with pain management. METHODS: In an academic pediatric hospital, nurse manager rounds were used to invite a conversation about pain management. The question, "Pain management is very important to us. Has your child's pain been well controlled?" was added to the established standard questions asked during nurse manager rounds. Effectiveness was measured using the preexisting Press Ganey survey question, "How well was your child's pain controlled?" Responses were compared between those patients who were and were not exposed to the rounding question. RESULTS: Data for 1,032 patients were used to establish baseline satisfaction with pain management scores. In the intervention period, 328 patients received nurse manager rounds and 121 did not. The median of the weighted mean patient survey satisfaction scores were baseline, 91.5%; receiving intervention, 94.2%; and not receiving intervention, 90.0%. Patients who received the intervention reported higher satisfaction with pain management than those who did not (p <0.0001). CONCLUSION: Hospitals seeking to improve satisfaction with pain management should encourage health care providers to reliably discuss pain control with pediatric patients.

Host community perspectives on trainees participating in short-term experiences in global health.

CONTEXT: High-income country (HIC) trainees are undertaking global health experiences in low- and middle-income country (LMIC) host communities in increasing numbers. Although the benefits for HIC trainees are well described, the benefits and drawbacks for LMIC host communities are not well captured. OBJECTIVES: This study evaluated the perspectives of supervising physicians and local programme coordinators from LMIC host communities who engaged with HIC trainees in the context of the latter's short-term experiences in global health. METHODS: Thirty-five semi-structured interviews were conducted with LMIC host community collaborators with a US-based, non-profit global health education organisation. Interviews took place in La Paz, Bolivia and New Delhi, India. Interview transcripts were assessed for recurrent themes using thematic analysis. RESULTS: Benefits for hosts included improvements in job satisfaction, local prestige, global connectedness, local networks, leadership skills, resources and sense of efficacy within their communities. Host collaborators called for improvements in HIC trainee attitudes and behaviours, and asked that trainees not make promises they would not fulfil. Findings also provided evidence of a desire for parity between the opportunities afforded to US-based staff and those available to LMIC-based partners. CONCLUSIONS: This study provides important insights into the perspectives of LMIC host community members in the context of short-term experiences in global health for HIC trainees. We hope to inform the behaviour of HIC trainees and institutions with regard to international partnerships and global health activities.

An Assessment of Physical and N6-Cyclohexyladenosine-Induced Hypothermia in Rodent Distal Focal Ischemic Stroke.

Therapeutic hypothermia (TH) mitigates damage in ischemic stroke models. However, safer and easier TH methods (e.g., pharmacological) are needed to circumvent physical cooling complications. This study evaluated systemic and pharmacologically induced TH using the adenosine A1 receptor agonist, N6-cyclohexyladenosine (CHA), with control groups in male Sprague-Dawley rats. CHA was administered intraperitoneally 10 minutes following a 2-hour intraluminal middle cerebral artery occlusion. We used a 1.5 mg/kg induction dose, followed by three 1.0 mg/kg doses every 6 hours for a total of 4 doses, causing 20-24 hours of hypothermia. Animals assigned to physical hypothermia and CHA-hypothermia had similar induction rates and nadir temperatures, but forced cooling lasted ∼6 hours longer compared with CHA-treated animals. The divergence is likely attributable to individual differences in CHA metabolism, which led to varied durations at nadir, whereas physical hypothermia was better regulated. Physical hypothermia significantly reduced infarction (primary endpoint) on day 7 (mean reduction of 36.8 mm3 or 39% reduction; p = 0.021 vs. normothermic animals; Cohen's d = 0.75), whereas CHA-induced hypothermia did not (p = 0.33). Similarly, physical cooling improved neurological function (physical hypothermia median = 0, physical normothermia median = 2; p = 0.008) and CHA-induced cooling did not (p > 0.99). Our findings demonstrate that forced cooling was neuroprotective compared with controls, but prolonged CHA-induced cooling was not neuroprotective.

Tissue Compliance and Intracranial Pressure Responses to Large Intracerebral Hemorrhage in Young and Aged Spontaneously Hypertensive Rats.

BACKGROUND: After a large intracerebral hemorrhage (ICH), the hematoma and swelling cause intracranial pressure (ICP) to increase, sometimes causing brain herniation and death. This is partly countered by widespread tissue compliance, an acute decrease in tissue volume distal to the stroke, at least in young healthy animals. Intracranial compensation dynamics seem to vary with age, but there is no data on old animals or those with hypertension, major factors influencing ICH risk and outcome. METHODS: We assessed hematoma volume, edema, ICP, and functional deficits in young and aged spontaneously hypertensive rats (SHRs) and young normotensive control strains after collagenase-induced ICH. Macroscopic and microscopic brain volume fractions, such as contralateral hemisphere volume, cortical thickness, and neuronal morphology, were assessed via histological and stereological techniques. RESULTS: Hematoma volume was 52% larger in young versus aged SHRs; surprisingly, aged SHRs still experienced proportionally worse outcomes following ICH, with 2× greater elevations in edema and ICP relative to bleed volume and 3× the degree of tissue compliance. Aged SHRs also experienced equivalent neurological deficits following ICH compared with their younger counterparts, despite the lack of significant age-related behavioral effects. Importantly, tissue compliance occurred across strains and age groups and was not impaired by hypertension or old age. CONCLUSIONS: Aged SHRs show considerable capacity for tissue compliance following ICH and seem to rely on such mechanisms more heavily in settings of elevated ICP. Therefore, the ICP compensation response to ICH mass effect varies across the lifespan according to risk factors such as chronic hypertension.

T(H)1, T(H)2, and T(H)17 cells instruct monocytes to differentiate into specialized dendritic cell subsets.

Monocytes and T helper (T(H)) cells rapidly infiltrate inflamed tissues where monocytes differentiate into inflammatory dendritic cells (DCs) through undefined mechanisms. Our studies indicate that T(H) cells frequently interact with monocytes in inflamed skin and elicit the differentiation of specialized DC subsets characteristic of these lesions. In psoriasis lesions, T(H)1 and T(H)17 cells interact with monocytes and instruct these cells to differentiate into T(H)1- and T(H)17-promoting DCs, respectively. Correspondingly, in acute atopic dermatitis, T(H)2 cells interact with monocytes and elicit the formation of T(H)2-promoting DCs. DC formation requires GM-CSF and cell contact, whereas T(H) subset specific cytokines dictate DC function and the expression of DC subset specific surface molecules. Moreover, the phenotypes of T cell-induced DC subsets are maintained after subsequent stimulation with a panel of TLR agonists, suggesting that T(H)-derived signals outweigh downstream TLR signals in their influence on DC function. These findings indicate that T(H) cells govern the formation and function of specialized DC subsets.

Manipulation of the HIF-Vegf pathway rescues methyl tert-butyl ether (MTBE)-induced vascular lesions.

Methyl tert-butyl ether (MTBE) has been shown to be specifically anti-angiogenic in piscine and mammalian model systems at concentrations that appear non-toxic in other organ systems. The mechanism by which MTBE targets developing vascular structures is unknown. A global transcriptome analysis of zebrafish embryos developmentally exposed to 0.00625-5mM MTBE suggested that hypoxia inducible factor (HIF)-regulated pathways were affected. HIF-driven angiogenesis via vascular endothelial growth factor (vegf) is essential to the developing vasculature of an embryo. Three rescue studies were designed to rescue MTBE-induced vascular lesions: pooled blood in the common cardinal vein (CCV), cranial hemorrhages (CH), and abnormal intersegmental vessels (ISV), and test the hypothesis that MTBE toxicity was HIF-Vegf dependent. First, zebrafish vegf-a over-expression via plasmid injection, resulted in significantly fewer CH and ISV lesions, 46 and 35% respectively, in embryos exposed to 10mM MTBE. Then HIF degradation was inhibited in two ways. Chemical rescue by N-oxaloylglycine significantly reduced CCV and CH lesions by 30 and 32% in 10mM exposed embryos, and ISV lesions were reduced 24% in 5mM exposed zebrafish. Finally, a morpholino designed to knock-down ubiquitin associated von Hippel-Lindau protein, significantly reduced CCV lesions by 35% in 10mM exposed embryos. In addition, expression of some angiogenesis related genes altered by MTBE exposure were rescued. These studies demonstrated that MTBE vascular toxicity is mediated by a down regulation of HIF-Vegf driven angiogenesis. The selective toxicity of MTBE toward developing vasculature makes it a potentially useful chemical in the designing of new drugs or in elucidating roles for specific angiogenic proteins in future studies of vascular development.

Adherence to Hormonal Therapies in Prostate Cancer.

INTRODUCTION: Hormonal therapy is the standard of care in prostate cancer treatment. The approval of the first oral androgen deprivation therapy, relugolix, to treat prostate cancer patients provides an opportunity to review adherence to oral and injectable/implantable hormonal therapies to aid patients and physicians in making informed decisions. METHODS: A PubMed search for available literature on adherence to hormonal therapy in prostate cancer was conducted, including published data on relugolix. RESULTS: Adherence to oral antiandrogen therapy was above 90% by medication possession ratio in several studies worldwide and from 75% to 91% by proportion of days covered. For injectable/implantable androgen deprivation therapy, adherence to treatment ranged from 71% to 95%. In general, 60% and 29% of injections were reported to be delayed by more than 1 week and 2 weeks, respectively, with some patients experiencing testosterone increases (tests above 50 ng/dL). Although real-world data on adherence to relugolix are currently unavailable, pharmacokinetic/pharmacodynamics models demonstrated that, if necessary, treatment interruption up to 7 days would still maintain testosterone suppression levels. CONCLUSIONS: In general, adherence to hormonal therapy is high in prostate cancer. Studies revealed that adherence to injectable androgen deprivation therapy dosing schedules is important to maintain castrate levels. Pharmacokinetic/pharmacodynamics models showed that relugolix treatment interruption up to 7 days had minimal impact on testosterone suppression levels.

A systematic review and meta-analysis on the efficacy of glibenclamide in animal models of intracerebral hemorrhage.

Intracerebral hemorrhage (ICH) is a devastating stroke with many mechanisms of injury. Edema worsens outcome and can lead to mortality after ICH. Glibenclamide (GLC), a sulfonylurea 1- transient receptor potential melastatin 4 (Sur1-Trpm4) channel blocker, has been shown to attenuate edema in ischemic stroke models, raising the possibility of benefit in ICH. This meta-analysis synthesizes current pre-clinical (rodent) literature regarding the efficacy of post-ICH GLC administration (vs. vehicle controls) on behaviour (i.e., neurological deficit, motor, and memory outcomes), edema, hematoma volume, and injury volume. Six studies (5 in rats and 1 in mice) were included in our meta-analysis (PROSPERO registration = CRD42021283614). GLC significantly improved behaviour (standardized mean difference (SMD) = -0.63, [-1.16, -0.09], n = 70-74) and reduced edema (SMD = -0.91, [-1.64, -0.18], n = 70), but did not affect hematoma volume (SMD = 0.0788, [-0.5631, 0.7207], n = 18-20), or injury volume (SMD = 0.2892, [-0.4950, 1.0734], n = 24). However, these results should be interpreted cautiously. Findings were conflicted with 2 negative and 4 positive reports, and Egger regressions indicated missing negative edema data (p = 0.0001), and possible missing negative behavioural data (p = 0.0766). Experimental quality assessed via the SYRCLE and CAMARADES checklists was concerning, as most studies demonstrated high risks of bias. Studies were generally low-powered (e.g., average n = 14.4 for behaviour), and future studies should employ sample sizes of 41 to detect our observed effect size in behaviour and 33 to detect our observed effect in edema. Overall, missing negative studies, low study quality, high risk of bias, and incomplete attention to key recommendations (e.g., investigating female, aged, and co-morbid animals) suggest that further high-powered confirmatory studies are needed before conclusive statements about GLC's efficacy in ICH can be made, and before further clinical trials are performed.

Describing the Patient Journey of Women with Claims for Uterine Fibroids and Heavy Menstrual Bleeding Using a Commercial Database (2011-2020).

Introduction: This retrospective database claims analysis describes the clinical characteristics and treatment patterns of commercially insured United States women with uterine fibroids (UF) and heavy menstrual bleeding (HMB). Methods: Women age 18-55 years with an incident UF diagnosis (index date) between 1/1/2012 and 12/31/2019 and ≥1 claim for HMB (UF-HMB), were identified from the Optum® Clinformatics® database. Outcomes included clinical characteristics, pharmacologic therapy use, and surgeries/procedures. Regression models were used to identify factors associated with time to post-diagnosis hormonal therapy and hysterectomy. Results: A total of 85,428 women had UF-HMB (mean [SD] age, 43.7 [6.4] years). The median follow-up was 3.2 years. After HMB, the most common symptoms were pelvic pressure/pain (27.6%) and backache (17.5%). Within 6 months of UF diagnosis, 40.2% of patients had received only pharmacologic therapy; 25.5% had received no treatment; 24.3% had a hysterectomy, and 10.0% had other procedures. By the end of follow-up, 50.0% had received a hysterectomy. Multiple factors were predictive of a higher likelihood of receiving hormonal therapy (geographic region, infertility, pre-index pregnancy) or hysterectomy (older age, prior hormonal treatment, specific bulk symptoms, White race). Conclusion: Within 6 months of UF diagnosis, fewer than one-half of women with UF-HMB had received hormonal therapy, one-quarter received no treatment, and one-quarter had received a hysterectomy or another gynecologic procedure. Patients who received a hysterectomy were more likely to be older, White, and to have bulk symptoms.

Performance of ChatGPT on USMLE: Potential for AI-assisted medical education using large language models.

We evaluated the performance of a large language model called ChatGPT on the United States Medical Licensing Exam (USMLE), which consists of three exams: Step 1, Step 2CK, and Step 3. ChatGPT performed at or near the passing threshold for all three exams without any specialized training or reinforcement. Additionally, ChatGPT demonstrated a high level of concordance and insight in its explanations. These results suggest that large language models may have the potential to assist with medical education, and potentially, clinical decision-making.

Colchicine pre-treatment and post-treatment does not worsen bleeding or functional outcome after collagenase-induced intracerebral hemorrhage.

Patients with intracerebral hemorrhage (ICH) are at increased risk for major ischemic cardiovascular and cerebrovascular events. However, the use of preventative antithrombotic therapy can increase the risk of ICH recurrence and worsen ICH-related outcomes. Colchicine, an anti-inflammatory agent, has the potential to mitigate inflammation-related atherothrombosis and reduce the risk of ischemic vascular events. Here we investigated the safety and efficacy of colchicine when used both before and acutely after ICH. We predicted that daily colchicine administration would not impact our safety measures but would reduce brain injury and improve functional outcomes associated with inflammation reduction. To test this, 0.05 mg/kg colchicine was given orally once daily to rats either before or after they were given a collagenase-induced striatal ICH. We assessed neurological impairments, intra-parenchymal bleeding, Perls positive cells, and brain injury to gauge the therapeutic impact of colchicine on brain injury. Colchicine did not significantly affect bleeding (average = 40.7 µL) at 48 hrs, lesion volume (average = 24.5 mm3) at 14 days, or functional outcome (median neurological deficit scale score at 2 days post-ICH = 4, i.e., modest deficits) from 1-14 days after ICH. Colchicine reduced the volume of Perls positive cells in the perihematomal zone, indicating a reduction in inflammation. Safety measures (body weight, food consumption, water consumption, hydration, body temperature, activity, and pain) were not affected by colchicine. Although colchicine did not confer neuroprotection or functional benefit, it was able to reduce perihematomal inflammation after ICH without increasing bleeding. Thus, our findings suggest that colchicine treatment is safe, unlikely to worsen bleeding, and is unlikely but may reduce secondary injury after an ICH if initiated early post ICH to reduce the risk of ischemic vascular events. These results are informative for the ongoing CoVasc-ICH phase II randomized trial (NCT05159219).

Early, Intense Rehabilitation Fails to Improve Outcome After Intra-Striatal Hemorrhage in Rats.

BACKGROUND: The formation and degradation of an intracerebral hemorrhage causes protracted cell death, and an extended window for intervention. Experimental studies find that rehabilitation mitigates late cell death, with accelerated hematoma clearance as a potential mechanism. OBJECTIVE: We assessed whether early, intense, enriched rehabilitation (ER, environmental enrichment and massed skills training) enhances functional benefit, reduces brain injury, and augments hematoma clearance. METHODS: In experiment 1, rats (n = 56) were randomized to intervention in the light (-L) or dark phase (-D) of their housing cycle, then to 10 days of ER or control (CON) treatment after collagenase-induced striatal intracerebral hemorrhage (ICH). ER rats were treated from 5 to 14 days after ICH. Behavior and residual hematoma volume was assessed on day 14. In experiment 2, rats (n = 72) were randomized to ER-D10, ER-D20, or CON-D. ER rats completed 10 or 20 days of training in the dark. Rats were euthanized on day 60 for histology. In both experiments, behavioral assessment was completed pre-ICH, pre-ER (day 4 post-ICH), and post-ER (experiment 1: days 13-14; experiment 2: days 16-17 and 30-31). RESULTS: Reaching intensity was high but similar between ER-D10 and ER-L10. Unlike previous work, rehabilitation did not alter skilled reaching or hematoma resolution. Varying ER duration also did not affect reaching success or lesion volume. CONCLUSIONS: In contrast to others, and under these conditions, our findings show that striatal ICH was generally unresponsive to rehabilitation. This highlights the difficulty of replicating and extending published work, perhaps owing to small inter-study differences.

Glibenclamide does not improve outcome following severe collagenase-induced intracerebral hemorrhage in rats.

Intracerebral hemorrhage (ICH) is a devastating insult with few effective treatments. Edema and raised intracranial pressure contribute to poor outcome after ICH. Glibenclamide blocks the sulfonylurea 1 transient receptor potential melastatin 4 (Sur1-Trpm4) channel implicated in edema formation. While glibenclamide has been found to improve outcome and reduce mortality in animal models of severe ischemic stroke, in ICH the effects are less clear. In our previous study, we found no benefit after a moderate-sized bleed, while others have reported benefit. Here we tested the hypothesis that glibenclamide may only be effective in severe ICH, where edema is an important contributor to outcome. Glibenclamide (10 µg/kg loading dose, 200 ng/h continuous infusion) was administered 2 hours post-ICH induced by collagenase injection into the striatum of adult rats. A survival period of 24 hours was maintained for experiments 1-3, and 72 hours for experiment 4. Glibenclamide did not affect hematoma volume (~81 µL) or other safety endpoints (e.g., glucose levels), suggesting the drug is safe. However, glibenclamide did not lessen striatal edema (~83% brain water content), ionic dyshomeostasis (Na+, K+), or functional impairment (e.g., neurological deficits (median = 10 out of 14), etc.) at 24 hours. It also did not affect edema at 72 h (~86% brain water content), or overall mortality rates (25% and 29.4% overall in vehicle vs. glibenclamide-treated severe strokes). Furthermore, glibenclamide appears to worsen cytotoxic edema in the peri-hematoma region (cell bodies were 46% larger at 24 h, p = 0.0017), but no effect on cell volume or density was noted elsewhere. Overall, these findings refute our hypothesis, as glibenclamide produced no favorable effects following severe ICH.

Not as "blurred" as expected? Acuity and spatial summation in the pain system.

ABSTRACT: Spatial acuity measured by 2-point discrimination (2PD) threshold and spatial summation of pain (SSp) are useful paradigms to probe the pain system in humans. Whether the results of these paradigms are influenced by different stimulus modalities and intensities is unclear. The aim of this study was to test 2PD controlling the stimulus modality and the intensity and to investigate the effect of modality on SSp. Thirty-seven healthy volunteers were tested for 2PDs with 2 stimulus modalities (electrocutaneous and mechanical) and intensity (noxious and innocuous). For each condition, participants received stimuli to either 1 or 2 points on their lower back with different distances (2-14 cm, steps of 2 cm). It was found that 2PDs were significantly smaller for noxious stimuli for both modalities. By contrast, between-modality comparison reproduced previous reports of impaired acuity for noxious stimulation. Higher pain intensities were reported when a larger area was stimulated (SSp), independent of the modality. Furthermore, reported pain intensities were higher when the distance between 2 stimulated areas was increased from 2 to 6 cm (P < 0.001), 8 cm (P < 0.01), and 14 cm (P < 0.01). 2PDs determined by mechanical and electrocutaneous stimuli were significantly correlated within both stimulus intensities, ie, innocuous (r = 0.34, P < 0.05) and noxious (r = 0.35, P < 0.05). The current results show 3 novel findings: (1) the precision of the pain system might be higher than in the innocuous (tactile) system when mechanical and electrocutaneous modalities are used, (2) the pattern of distance-based and area-based SSp seems to be comparable irrespective of the modality applied (mechanical and electrocutaneous), and (3) both modalities are moderately correlated.

A pilot, randomized controlled trial of telementorship: A useful tool during social distancing.

BACKGROUND: During social distancing, resident mentorship may be an unmet need. Telementorship, mentorship through video conferencing software, presents a unique approach to overcome these challenges. AIMS: This study evaluated whether telementorship through video conference increased access to mentorship encounters and decreased perceived barriers to access, factors that determine likelihood to maintain mentor relationships, and quality of mentorship. METHODS: A year-long randomized, prospective cohort study was conducted in 2016-2017 with pairs of resident mentors from seven different training programs and medical student mentees, randomized to telementorship or in-person mentorship. The number of quarterly encounters was monitored and demographic predictors of meeting were determined. Likert scale survey responses were analyzed with linear regression. RESULTS: Forty-three of 46 (93.5%) volunteer mentor-mentee pairs participated. Telementorship did not alter likelihood of meeting or attitudes toward mentorship barriers (time and distance). Mentee satisfaction increased from 42.5% to 65.4% (P<0.05) throughout the year. Operating room-based practice (P<0.05) and higher postgraduate level (P=0.02) decreased the likelihood of meeting. CONCLUSION: Telementorship provided an equal number of encounters compared to the pairs who were asked to meet in-person. Telementorship may serve as an adjunct modality for flexible communication. RELEVANCE FOR PATIENTS: Medical mentorship is a key component to medical education. Effective mentorship increases academic research productivity, job satisfaction, and advancement of clinical skills, which translate to improved patient care.

An update to the Monro-Kellie doctrine to reflect tissue compliance after severe ischemic and hemorrhagic stroke.

High intracranial pressure (ICP) can impede cerebral blood flow resulting in secondary injury or death following severe stroke. Compensatory mechanisms include reduced cerebral blood and cerebrospinal fluid volumes, but these often fail to prevent raised ICP. Serendipitous observations in intracerebral hemorrhage (ICH) suggest that neurons far removed from a hematoma may shrink as an ICP compliance mechanism. Here, we sought to critically test this observation. We tracked the timing of distal tissue shrinkage (e.g. CA1) after collagenase-induced striatal ICH in rat; cell volume and density alterations (42% volume reduction, 34% density increase; p < 0.0001) were highest day one post-stroke, and rebounded over a week across brain regions. Similar effects were seen in the filament model of middle cerebral artery occlusion (22% volume reduction, 22% density increase; p ≤ 0.007), but not with the Vannucci-Rice model of hypoxic-ischemic encephalopathy (2.5% volume increase, 14% density increase; p ≥ 0.05). Concerningly, this 'tissue compliance' appears to cause sub-lethal damage, as revealed by electron microscopy after ICH. Our data challenge the long-held assumption that 'healthy' brain tissue outside the injured area maintains its volume. Given the magnitude of these effects, we posit that 'tissue compliance' is an important mechanism invoked after severe strokes.

Retrospective Review of the Safety and Efficacy of Virtual Reality in a Pediatric Hospital.

INTRODUCTION: Virtual reality (VR) is an emerging tool for anxiety and fear reduction in pediatric patients. VR use is facilitated by Certified Child Life Specialists (CCLS) at pediatric hospitals. The primary aim of this study was to retrospectively review the safety of VR by analyzing adverse events after the utilization of VR under CCLS supervision. Secondary objectives were to characterize the efficacy of VR in enhancing patient cooperation, describe the integration of VR into Child Life services, and identify interventions that accompanied VR. METHODS: The Stanford Chariot Program developed VR applications, customized VR interfaces, and patient head straps, and distributed these to CCLS. Chart review analyzed VR utilization through CCLS patient notes. Inclusion criteria were all patients ages 6 to 18-years-old who received a Child Life intervention. RESULTS: From June 2017 to July 2018, 31 CCLS saw 8,098 patients, 3,696 of which met age criteria with pre- and post-intervention cooperation data. Two hundred thirteen patients received VR with an accompanying intervention, while 34 patients received only VR. Adverse events were rare, and included increased anxiety (3.8%, n=8), dizziness (0.5%, n=1), and nausea (0.5%, n=1). Patients were more likely to be cooperative after receiving VR (99.5%, n=212) compared to pre-intervention (96.7%, n=206, p=0.041). VR use was most common in the perioperative setting (60%, n=128), followed by outpatient clinics (15%, n=32). CONCLUSION: VR is safe in pediatric patients with appropriate hardware, software, and patient selection. Side effects were rare and self-limited. VR appears to be associated with improvements in cooperation.

The collagenase model of intracerebral hemorrhage in awake, freely moving animals: The effects of isoflurane.

Intracerebral hemorrhage (ICH) is a devastating stroke often modelled in rats. Isoflurane anesthetic, commonly used in preclinical research, affects general physiology (e.g., blood pressure) and electrophysiology (e.g., burst suppression) in many ways. These physiological changes may detract from the clinical relevance of the model. Here, we revised the standard collagenase model to produce an ICH in rats without anesthetic. Guide cannulas were implanted stereotaxically under anesthetic. After 3 days of recovery, collagenase was infused through an internal cannula into the striatum of animals randomly assigned to the non-anesthetized or isoflurane group. We assessed whether isoflurane affected hematoma volume, core temperature, movement activity, pain, blood pressure, and seizure activity. With a small ICH, there was a hematoma volume increased from 8.6 (±3.3, 95% confidence interval) µL in anesthetized rats to 13.2 (±3.1) µL in non-anesthetized rats (P = 0.008), but with a larger ICH, hematoma volumes were similar. Isoflurane decreased temperature by 1.3 °C (±0.16 °C, P < 0.001) for 2 h and caused a 35.1 (±1.7) mmHg group difference in blood pressure (P < 0.007) for 12 m. Blood glucose increased twofold after isoflurane procedures (P < 0.001). Pain, as assessed with the rat grimace scale, did not differ between groups. Seizure incidence rate (62.5%) in non-anesthetized ICH rats was similar to historic amounts (61.3%). In conclusion, isoflurane appears to have some significant and injury size-dependent effects on the collagenase model. Thus, when anesthetic effects are a known concern, the use of the standardized cannula infusion approach is scientifically and ethically acceptable.