Evaluation of the influence of platelet-rich plasma (PRP), platelet lysate (PL) and mechanical loading on chondrogenesis in vitro.

The aim of this work is to investigate the capability of PRP as an adjuvant therapy to autologous chondrocyte implantation (ACI) in combination with multi-axial load with respect to cartilage regeneration. Articular cartilage shows poor repair capacity and therapies for cartilage defects are still lacking. Well-established operative treatments include ACI, and growing evidence shows the beneficial effects of PRP. Platelets contain numerous growth factors, among them transforming growth factor beta (TGF-ß). Dynamic mechanical loading is known to be essential for tissue formation, improving extracellular matrix (ECM) production. For our ACI model monolayer expanded human chondrocytes were seeded into polyurethane scaffolds and embedded in fibrin (hChondro), in PRP-Gel (PRP), or in fibrin with platelet lysate (PL), which was added to the media once a week with a concentration of 50 vol%. The groups were either exposed to static conditions or multi-axial forces in a ball-joint bioreactor for 1 h per day over 2 weeks, mimicking ACI under physiological load. The culture medium was collected and analyzed for glycosaminoglycan (GAG), nitrite and transforming growth factor beta 1 (TGF-ß1) content. The cell-scaffold constructs were collected for DNA and GAG quantification; the expression of chondrogenic genes, TGF-ß and related receptors, as well as inflammatory genes, were analyzed using qPCR. Loading conditions showed superior chondrogenic differentiation (upregulation of COL2A1, ACAN, COMP and PRG4 expression) than static conditions. PRP and PL groups combined with mechanical loading showed upregulation of COL2A1, ACAN and COMP. The highest amount of total TGF-ß1 was quantified in the PL group. Latent TGF-ß1 was activated in all loaded groups, while the highest amount was found in the PL group. Load increased TGFBR1/TGFBR2 mRNA ratio, with further increases in response to supplements. In general, loading increased nitrite release into the media. However, over time, the media nitrite content was lower in the PL group compared to the control group. Based on these experiments, we conclude that chondrogenic differentiation is strongest when simulated ACI is performed in combination with dynamic mechanical loading and PRP-gel or PL supplementation. An inflammatory reaction was reduced by PRP and PL, which could be one of the major therapeutic effects. Loading presumably can enhance the action of TGF-ß1, which was predominantly activated in loaded PL groups. The combination of load and PRP represents an effective and promising synergy concerning chondrocyte-based cartilage repair.

Vaginal lubricants and moisturizers: a review into use, efficacy, and safety.

Vaginal dryness is common during and after menopause due to declining estrogen. It is one of the symptoms of vulvovaginal atrophy (VVA), which is part of the genitourinary syndrome of menopause. This can be distressing for women and cause pain, discomfort, and dyspareunia. Vaginal dryness affects over 50% of postmenopausal women but is under-reported and thus under-treated due to barriers to seeking help. Estrogen replacement can resolve symptoms, but may be contraindicated or not desired by all women. Over-the-counter vaginal moisturizers and lubricants can ease the symptoms of VVA. However, their chemical composition varies enormously and some are known to cause detrimental effects due to unphysiological pH, osmolality, and additives. The primary purpose of this review is to assess both their efficacy and safety. Women should be directed toward products that are as 'body-similar' as possible to vaginal secretions in terms of pH and osmolality. Products with potentially harmful ingredients should be avoided. Lubricants can be trialed for sexual activity and moisturizers for symptom control, even if topical or systemic menopause hormone therapy is being used.

Fluctuations of consciousness after stroke: Associations with the confusion assessment method for the intensive care unit (CAM-ICU) and potential undetected delirium.

PURPOSE: To examine associations between fluctuating consciousness and Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) assessments in stroke patients compared to non-neurological patients. MATERIALS AND METHODS: We linked all recorded CAM-ICU assessments with corresponding Richmond Agitation Sedation Scale (RASS) measurements in patients with stroke or sepsis from a single-center ICU database. Fluctuating consciousness was defined by RASS variability using standard deviations (SD) over 24-h periods; regression analyses were performed to determine associations with RASS variability and CAM-ICU rating. RESULTS: We identified 16,509 paired daily summaries of CAM-ICU and RASS measurements in 546 stroke patients and 1586 sepsis patients. Stroke patients had higher odds of positive (OR 4.2, 95% CI 3.3-5.5) and "unable to assess" (UTA; OR 5.2, 95% CI 4.0-6.8) CAM-ICU ratings compared to sepsis patients, and CAM-ICU-positive and UTA assessment-days had higher RASS variability than CAM-ICU-negative assessment-days, especially in stroke patients. Based on model-implied associations of RASS variability (OR 2.0 per semi-IQR-difference in RASS-SD, 95% CI 1.7-2.2) and stroke diagnosis (OR 2.7, 95% CI 2.0-3.7) with CAM-ICU-positive assessments, over one-third of probable delirium cases among stroke patients were potentially missed by the CAM-ICU. CONCLUSIONS: Post-stroke delirium may frequently go undetected by the CAM-ICU, even in the setting of fluctuating consciousness.

12 versus 24 h bed rest after acute ischemic stroke thrombolysis: a preliminary experience.

BACKGROUND: The practice of ≥24 h of bed rest after acute ischemic stroke thrombolysis is common among hospitals, but its value compared to shorter periods of bed rest is unknown. METHODS: Consecutive adult patients with a diagnosis of ischemic stroke who had received intravenous thrombolysis treatment from 1/1/2010 until 4/13/2016, identified from the local ischemic stroke registry, were included. Standard practice bed rest for ≥24 h, the protocol prior to 1/27/2014, was retrospectively compared with standard practice bed rest for ≥12 h, the protocol after that date. The primary outcome was favorable discharge location (defined as home, home with services, or acute rehabilitation). Secondary outcome measures included incidence of pneumonia, NIHSS at discharge, and length of stay. RESULTS: 392 patients were identified (203 in the ≥24 h group, 189 in the ≥12 h group). There was no significant difference in favorable discharge outcome in the ≥24 h bed rest protocol compared with the ≥12 h bed rest protocol in multivariable logistic regression analysis (76.2% vs. 70.9%, adjusted OR 1.20 CI 0.71-2.03). Compared with the ≥24 h bed rest group, pneumonia rates (8.3% versus 1.6%, adjusted OR 0.12 CI 0.03-0.55), median discharge NIHSS (3 versus 2, adjusted p = .034), and mean length of stay (5.4 versus 3.5 days, adjusted p = .006) were lower in the ≥12 h bed rest group. CONCLUSION: Compared with ≥24 h bed rest, ≥12 h bed rest after acute ischemic stroke reperfusion therapy appeared to be similar. A non-inferiority randomized trial is needed to verify these findings.

Yield of diagnostic imaging in atraumatic convexity subarachnoid hemorrhage.

INTRODUCTION: Atraumatic convexity subarachnoid hemorrhage is a subtype of spontaneous subarachnoid hemorrhage that often presents a diagnostic challenge. Common etiologies include cerebral amyloid angiopathy, vasculopathies, and coagulopathy; however, aneurysm is rare. Given the broad differential of causes of convexity subarachnoid hemorrhage, we assessed the diagnostic yield of common tests and propose a testing strategy. METHODS: We performed a single-center retrospective study on consecutive patients with atraumatic convexity subarachnoid hemorrhage over a 2-year period. We obtained and reviewed each patient's imaging and characterized the frequency with which each test ultimately diagnosed the cause. Additionally, we discuss clinical features of patients with convexity subarachnoid hemorrhage with respect to the mechanism of hemorrhage. RESULTS: We identified 70 patients over the study period (mean (SD) age 64.70 (16.9) years, 35.7% men), of whom 58 patients (82%) had a brain MRI, 57 (81%) had non-invasive vessel imaging, and 27 (38.5%) underwent catheter-based angiography. Diagnoses were made using only non-invasive imaging modalities in 40 patients (57%), while catheter-based angiography confirmed the diagnosis in nine patients (13%). Further clinical history and laboratory testing yielded a diagnosis in an additional 17 patients (24%), while the cause remained unknown in four patients (6%). CONCLUSION: The etiology of convexity subarachnoid hemorrhage may be diagnosed in most cases via non-invasive imaging and a thorough clinical history. However, catheter angiography should be strongly considered when non-invasive imaging fails to reveal the diagnosis or to better characterize a vascular malformation. Larger prospective studies are needed to validate this algorithm.

Single-cell analysis identifies CRLF2 rearrangements as both early and late events in Down syndrome and non-Down syndrome acute lymphoblastic leukaemia.

Deregulated expression of the type I cytokine receptor, CRLF2, is observed in 5-15% of precursor B-cell acute lymphoblastic leukaemia (B-ALL). We have previously reported the genomic landscape of patients with CRLF2 rearrangements (CRLF2-r) using both whole genome and exome sequencing, which identified a number of potential clonal and sub-clonal genomic alterations. In this study, we aimed to assess when the CRLF2-r; IGH-CRLF2 or P2RY8-CRLF2, arose during the evolution of both Down syndrome-ALL (DS-ALL) and non-DS-ALL. Using fluorescence in situ hybridisation, we were able to track up to four structural variants in single cells from 47 CRLF2-r B-ALL patients, which in association with our multiplex single-cell analysis of a further four patients, permitted simultaneous tracking of copy number alterations, structural and single nucleotide variants within individual cells. We observed CRLF2-r arising as both early and late events in DS and non-DS-ALL patients. Parallel evolution of discrete clones was observed in the development of CRLF2-r B-ALL, either involving the CRLF2-r or one of the other tracked abnormalities. In-depth single-cell analysis identified both linear and branching evolution with early clones harbouring a multitude of abnormalities, including the CRLF2-r in DS-ALL patients.

Baseline NIH Stroke Scale is an inferior predictor of functional outcome in the era of acute stroke intervention.

Background and aims Baseline National Institutes of Health Stroke Scale (NIHSS) scores have frequently been used for prognostication after ischemic stroke. With the increasing utilization of acute stroke interventions, we aimed to determine whether baseline NIHSS scores are still able to reliably predict post-stroke functional outcome. Methods We retrospectively analyzed prospectively collected data from a high-volume tertiary-care center. We tested strength of association between NIHSS scores at baseline and 24 h with discharge NIHSS using Spearman correlation, and diagnostic accuracy of NIHSS scores in predicting favorable outcome at three months (defined as modified Rankin Scale 0-2) using receiver operating characteristic curve analysis with area under the curve. Results There were 1183 patients in our cohort, with median baseline NIHSS 8 (IQR 3-17), 24-h NIHSS 4 (IQR 1-11), and discharge NIHSS 2 (IQR 1-8). Correlation with discharge NIHSS was r = 0.60 for baseline NIHSS and r = 0.88 for 24-h NIHSS. Of all patients with follow-up data, 425/1037 (41%) had favorable functional outcome at three months. Receiver operating characteristic curve analysis for predicting favorable outcome showed area under the curve 0.698 (95% CI 0.664-0.732) for baseline NIHSS, 0.800 (95% CI 0.772-0.827) for 24-h NIHSS, and 0.819 (95% CI 0.793-0.845) for discharge NIHSS; 24 h and discharge NIHSS maintained robust predictive accuracy for patients receiving mechanical thrombectomy (AUC 0.846, 95% CI 0.798-0.895; AUC 0.873, 95% CI 0.832-0.914, respectively), while accuracy for baseline NIHSS decreased (AUC 0.635, 95% CI 0.566-0.704). Conclusion Baseline NIHSS scores are inferior to 24 h and discharge scores in predicting post-stroke functional outcomes, especially in patients receiving mechanical thrombectomy.

Level of consciousness at discharge and associations with outcome after ischemic stroke.

BACKGROUND: Many factors may potentially complicate the stroke recovery process, including persistently impaired level of consciousness (LOC)-whether from residual stroke effects or from superimposed delirium. We aimed to determine the degree to which impaired LOC at hospital discharge is associated with outcomes after ischemic stroke. METHODS: We conducted a single-center retrospective cohort study using prospectively-collected data from 2015 to 2017, collecting total NIHSS-LOC score at discharge as well as subscores for responsiveness (LOC-R), orientation questions (LOC-Q), and command-following (LOC-C). We determined associations between LOC scores and 3-month outcome using logistic regression, with discharge location (skilled nursing facility [SNF] vs. inpatient rehabilitation) representing a pre-specified secondary outcome. RESULTS: We identified 1003 consecutive patients with ischemic stroke who survived to discharge, of whom 32% had any LOC score > 0. Total LOC score at discharge was associated with unfavorable 3-month outcome (OR 4.9 [95% CI 2.4-9.8] for LOC = 1; OR 8.0 [2.7-23.9] for LOC = 2-3; OR 6.3 [2.1-18.5] for LOC = 4-5; all patients with LOC = 6-7 had poor outcomes), as were subscores for LOC-R (OR 5.3 [1.3-21.2] for LOC-R = 1; all patients with LOC-R = 2-3 had poor outcomes) and LOC-Q (OR 4.1 [2.1-8.3] for LOC-Q = 1; OR 4.9 [1.8-13.5] for LOC-Q = 2). Total LOC score (OR 2.6 [1.3-5.3] for LOC = 1; OR 3.1 [1.2-8.2] for LOC = 2-3) and LOC-Q (OR 3.3 [1.6-6.6] for LOC-Q = 1; OR 3.4 [1.3-9.0] for LOC-Q = 2) were also associated with discharge to SNF rather than to inpatient rehabilitation. CONCLUSIONS: The presence of impaired consciousness or disorientation at discharge is associated with markedly worse outcomes after ischemic stroke. Further studies are necessary to determine the separate effects of residual stroke-related LOC changes and those caused by superimposed delirium.

Safety and Costs of Stroke Unit Admission for Select Acute Intracerebral Hemorrhage Patients.

BACKGROUND AND PURPOSE: There are limited data to guide intensive care unit (ICU) versus dedicated stroke unit (SU) admission for intracerebral hemorrhage (ICH) patients. We hypothesized select patients can be safely cared for in SU versus ICU at lower costs. METHODS: We conducted a retrospective cohort study of consecutive patients with predefined minor ICH (≤20 cm3, supratentorial, no coagulopathy) receiving care in either an ICU or an SU. Multiple linear regression and inverse probability weighting were used to adjust for differences in patient characteristics and nonrandom ICU versus SU assignment. The primary outcome was poor functional status at discharge (modified Rankin score [mRS] ≥3). Secondary outcomes included complications, discharge disposition, hospital length of stay, and direct inpatient costs. RESULTS: The study population included 104 patients (41 admitted to the ICU and 63 admitted to the SU). After controlling for differences in baseline characteristics, there were no differences in poor functional outcome at discharge (93% vs 85%, P = .26) or in mean mRS (2.9 vs 3.0, P = .73). Similarly, there were no differences in the rates of complications (6% vs 10%, P = .44), discharged dead or to a skilled nursing facility (8% vs 13%, P = .59), or direct patient costs (US$7100 vs US$6200, P = .33). Median length of stay was significantly longer in the ICU group (5 vs 4 days, P = .01). CONCLUSIONS: This study revealed a shorter length of stay but no large differences in functional outcome, safety, or cost among patients with minor ICH admitted to a dedicated SU compared to an ICU.

Procalcitonin is a Poor Predictor of Non-Infectious Fever in the Neurocritical Care Unit.

BACKGROUND: Fever is a common occurrence in the Neurocritical Care Unit (NCCU). It is reported that up to 50 % of these fevers are associated with a non-infectious source. As this is a diagnosis of exclusion, a complete fever evaluation must be done to rule out infection. Procalcitonin (PCT) has been identified as a possible biomarker to distinguish infectious from non-infectious etiologies of fever. We hypothesized that PCT could be used as a predictor of infectious fever in febrile patients with intracranial hemorrhage admitted to the NCCU. METHODS: A prospective observational cohort of patients admitted to a 12-bed NCCU in a tertiary-care university hospital from January 1, 2014, to October 1, 2014, was studied. Patients with intracranial hemorrhage (aneurismal subarachnoid hemorrhage, traumatic brain injury, intracerebral hemorrhage, or non-traumatic subdural hemorrhage) and fever defined as ≥101.4 °F were included. All patients had a urinalysis, chest X-ray, two sets of blood cultures, and PCT as part of their fever evaluation. Patients also had urine, sputum, CSF cultures, and Clostridium difficile toxin PCR as clinically indicated. Patients with incomplete fever evaluations were excluded. RESULTS: Seventy-three patients met inclusion criteria: 36 had infections identified and 37 did not. Type of intracranial hemorrhage was similar between groups. For those with identified infection, median PCT was 0.15 ng/mL (IQR 0.06-0.5 ng/mL). For those without identified infection, median PCT was 0.09 ng/mL (IQR 0.05-0.45 ng/mL), p = 0.30. Analyzing subgroups of intracranial hemorrhage patients revealed no group with a significant difference in PCT values. Patients with identified infection did have higher white blood cell counts (median 14.1 × 109/L (11.6-17.4 × 109/L) compared to those without identified infection 12 × 109/L (9.9-14.1 × 109/L), p = 0.02. CONCLUSION: Among patients with intracranial hemorrhage, PCT did not differentiate infectious fever from non-infectious fever.

Olfactory neuroblastoma: 14-year experience at an Australian tertiary centre and the role for longer-term surveillance.

BACKGROUND: Olfactory neuroblastoma is a rare sinonasal malignancy, with poorly defined treatment protocols. Management at a tertiary centre was retrospectively evaluated to inform future treatment and follow up. METHODS: Cases treated with curative intent (2000-2014) were included. Data were collected, and overall and disease-free survival rates were calculated. RESULTS: Eleven cases were identified, with a median follow up of 87 months. One patient was Kadish stage A, one was stage B, eight were stage C and one was stage D. The latter patient underwent chemoradiotherapy alone. The remaining patients proceeded to: endoscopic-assisted wide local excision (n = 2), anterior craniofacial resection (n = 4) or endoscopic craniofacial resection (n = 4). No patients had primary nodal disease or elective neck treatment. One patient had neoadjuvant chemoradiation. Six patients had post-operative radiotherapy; three received adjuvant chemotherapy. Two patients had late cervical node failure, and proceeded to neck dissection and post-operative radiotherapy. Two patients had late local recurrence. Ten-year overall and disease-free survival rates were 68.2 and 46.7 per cent, respectively. CONCLUSION: Longer-term follow up is supported given the incidence of late regional and local recurrence. Prophylactic treatment of cervical nodes in locally advanced disease is an area for further investigation.

Utilization of long-term care after decompressive hemicraniectomy for severe stroke among older patients.

BACKGROUND: While clinical trial data support decompressive hemicraniectomy (DHC) as improving survival among patients with severe ischemic stroke, quality of life outcomes among older persons remain controversial. AIMS: To aid decision-making and understand practice variation, we measured long-term outcomes and patterns of regional variation for a nationwide cohort of ischemic stroke patients after DHC. METHODS: Medicare fee-for-service ischemic stroke cases over age 65 during the year 2008 were used to create a cohort followed for 2 years (2009-2010) after stroke and DHC procedure. Rates of mortality, acute hospital readmission, and long-term care (LTC) utilization were calculated. Multiple logistic regression was used to identify individual predictors of institutional LTC. Regional variation in DHC was calculated through aggregation and merging with the state-level data. RESULTS: Among 397,503 acute ischemic stroke patients, 130 (0.03 %) underwent DHC. Mean age was 72 years, and 75 % were between the ages of 65 and 74. Mortality was highest (38 %) within the first 30 days. At 2 years, 59 % of the original cohort had died. The 30-day rate of acute hospital readmission was 25 %. Among survivors, 75 % returned home 1 year after index stroke admission. States with higher per capita health expenditures were associated with wider variation in utilization of DHC. CONCLUSIONS: There is a high rate of mortality among older stroke patients undergoing DHC. Although most survivors of DHC are not permanently institutionalized, there is wide variation in utilization of DHC across the USA.

Effect of Probiotics on the Incidence of Healthcare-Associated Infections in Mechanically Ventilated Neurocritical Care Patients.

BACKGROUND: Healthcare-associated infections (HAIs) are seen in 17% of critically ill patients. Probiotics, live nonpathogenic microorganisms, may aid in reducing the incidence of infection in critically ill patients. We hypothesized that administration of probiotics would be safe and reduce the incidence of HAIs among mechanically ventilated neurocritical care patients. METHODS: We assembled 2 retrospective cohorts of mechanically ventilated neurocritical care patients. In the preintervention cohort from July 1, 2011, to December 31, 2011, probiotics were not used. In the postintervention group from July 1, 2012, to December 31, 2012, 1 g of a combination of Lactobacillus acidophilus and Lactobacillus helveticus was administered twice daily to all patients who were mechanically ventilated for more than 24 hours. RESULTS: There were a total of 167 patients included, 80 patients in the preintervention group and 87 patients in the postintervention group. No patients in the preintervention group received probiotics. Eighty-five (98%) patients in the postintervention group received probiotics for a median of 10 days (interquartile range, 4-20 days). There were 14 (18%) HAIs in the preintervention group and 8 (9%) HAIs in the postintervention group (P = .17). Ventilator days, lengths of stay, in-hospital mortality, and discharge disposition were similar between the pre- and postintervention groups. There were no cases of Lactobacillus bacteremia or other adverse events associated with probiotics use. CONCLUSION: Probiotics are safe to administer in neurocritical care patients; however, this study failed to demonstrate a significant decrease in HAIs or secondary outcomes associated with probiotics.

Post-Acute Care Data for Predicting Readmission After Ischemic Stroke: A Nationwide Cohort Analysis Using the Minimum Data Set.

BACKGROUND: Reducing hospital readmissions is a key component of reforms for stroke care. Current readmission prediction models lack accuracy and are limited by data being from only acute hospitalizations. We hypothesized that patient-level factors from a nationwide post-acute care database would improve prediction modeling. METHODS AND RESULTS: Medicare inpatient claims for the year 2008 that used International Classification of Diseases, Ninth Revision codes were used to identify ischemic stroke patients older than age 65. Unique individuals were linked to comprehensive post-acute care assessments through use of the Minimum Data Set (MDS). Logistic regression was used to construct risk-adjusted readmission models. Covariates were derived from MDS variables. Among 39 178 patients directly admitted to nursing homes after hospitalization due to acute stroke, there were 29 338 (75%) with complete MDS assessments. Crude rates of readmission and death at 30 days were 8448 (21%) and 2791 (7%), respectively. Risk-adjusted models identified multiple independent predictors of all-cause 30-day readmission. Model performance of the readmission model using MDS data had a c-statistic of 0.65 (95% CI 0.64 to 0.66). Higher levels of social engagement, a marker of nursing home quality, were associated with progressively lower odds of readmission (odds ratio 0.71, 95% CI 0.55 to 0.92). CONCLUSIONS: Individual clinical characteristics from the post-acute care setting resulted in only modest improvement in the c-statistic relative to previous models that used only Medicare Part A data. Individual-level characteristics do not sufficiently account for the risk of acute hospital readmission.

Microscale spatiotemporal dynamics during neocortical propagation of human focal seizures.

Some of the most clinically consequential aspects of focal epilepsy, e.g. loss of consciousness, arise from the generalization or propagation of seizures through local and large-scale neocortical networks. Yet, the dynamics of such neocortical propagation remain poorly understood. Here, we studied the microdynamics of focal seizure propagation in neocortical patches (4×4 mm) recorded via high-density microelectrode arrays (MEAs) implanted in people with pharmacologically resistant epilepsy. Our main findings are threefold: (1) a newly developed stage segmentation method, applied to local field potentials (LFPs) and multiunit activity (MUA), revealed a succession of discrete seizure stages, each lasting several seconds. These different stages showed characteristic evolutions in overall activity and spatial patterns, which were relatively consistent across seizures within each of the 5 patients studied. Interestingly, segmented seizure stages based on LFPs or MUA showed a dissociation of their spatiotemporal dynamics, likely reflecting different contributions of non-local synaptic inputs and local network activity. (2) As previously reported, some of the seizures showed a peak in MUA that happened several seconds after local seizure onset and slowly propagated across the MEA. However, other seizures had a more complex structure characterized by, for example, several MUA peaks, more consistent with the succession of discrete stages than the slow propagation of a simple wavefront of increased MUA. In both cases, nevertheless, seizures characterized by spike-wave discharges (SWDs, ~2-3 Hz) eventually evolved into patterns of phase-locked MUA and LFPs. (3) Individual SWDs or gamma oscillation cycles (25-60 Hz), characteristic of two different types of recorded seizures, tended to propagate with varying degrees of directionality, directions of propagation and speeds, depending on the identified seizure stage. However, no clear relationship was observed between the MUA peak onset time (in seizures where such peak onset occurred) and changes in MUA or LFP propagation patterns. Overall, our findings indicate that the recruitment of neocortical territories into ictal activity undergoes complex spatiotemporal dynamics evolving in slow discrete states, which are consistent across seizures within each patient. Furthermore, ictal states at finer spatiotemporal scales (individual SWDs or gamma oscillations) are organized by slower time scale network dynamics evolving through these discrete stages.

Clonal origins of ETV6-RUNX1⁺ acute lymphoblastic leukemia: studies in monozygotic twins.

Studies on twins with concordant acute lymphoblastic leukemia (ALL) have revealed that ETV6-RUNX1 gene fusion is a common, prenatal genetic event with other driver aberrations occurring subclonally and probably postnatally. The fetal cell type that is transformed by ETV6-RUNX1 is not identified by such studies or by the analysis of early B-cell lineage phenotype of derived progeny. Ongoing, clonal immunoglobulin (IG) and cross-lineage T-cell receptor (TCR) gene rearrangements are features of B-cell precursor leukemia and commence at the pro-B-cell stage of normal B-cell lineage development. We reasoned that shared clonal rearrangements of IG or TCR genes by concordant ALL in twins would be informative about the fetal cell type in which clonal advantage is elicited by ETV6-RUNX1. Five pairs of twins were analyzed for all varieties of IG and TCR gene rearrangements. All pairs showed identical incomplete or complete variable-diversity-joining junctions coupled with substantial, subclonal and divergent rearrangements. This pattern was endorsed by single-cell genetic scrutiny in one twin pair. Our data suggest that the pre-leukemic initiating function of ETV6-RUNX1 fusion is associated with clonal expansion early in the fetal B-cell lineage.

Neuronal ensemble synchrony during human focal seizures.

Seizures are classically characterized as the expression of hypersynchronous neural activity, yet the true degree of synchrony in neuronal spiking (action potentials) during human seizures remains a fundamental question. We quantified the temporal precision of spike synchrony in ensembles of neocortical neurons during seizures in people with pharmacologically intractable epilepsy. Two seizure types were analyzed: those characterized by sustained gamma (∼40-60 Hz) local field potential (LFP) oscillations or by spike-wave complexes (SWCs; ∼3 Hz). Fine (<10 ms) temporal synchrony was rarely present during gamma-band seizures, where neuronal spiking remained highly irregular and asynchronous. In SWC seizures, phase locking of neuronal spiking to the SWC spike phase induced synchrony at a coarse 50-100 ms level. In addition, transient fine synchrony occurred primarily during the initial ∼20 ms period of the SWC spike phase and varied across subjects and seizures. Sporadic coherence events between neuronal population spike counts and LFPs were observed during SWC seizures in high (∼80 Hz) gamma-band and during high-frequency oscillations (∼130 Hz). Maximum entropy models of the joint neuronal spiking probability, constrained only on single neurons' nonstationary coarse spiking rates and local network activation, explained most of the fine synchrony in both seizure types. Our findings indicate that fine neuronal ensemble synchrony occurs mostly during SWC, not gamma-band, seizures, and primarily during the initial phase of SWC spikes. Furthermore, these fine synchrony events result mostly from transient increases in overall neuronal network spiking rates, rather than changes in precise spiking correlations between specific pairs of neurons.

Severe cerebral vasospasm after traumatic brain injury.

Severe traumatic brain injury is associated with both acute and delayed neuro- logical injury. Cerebral vasospasm is commonly associated with delayed neurological decline in aneurysmal subarachnoid hemorrhage patients. However, the role played by vasospasm in traumatic brain injury is less clear. Vasospasm occurs earlier, for a shorter duration, and often without significant neurological consequence among traumatic brain injury patients. Detection and management strategies for vasospasm in aneurysmal subarachnoid hemorrhage are not easily transferrable to traumatic brain injury patients. We present a patient with a severe traumatic brain injury who had dramatic improvement following emergent decompressive hemicraniectomy. Two weeks after initial presentation he suffered a precipitous decline despite intensive surveillance. This case illustrates the distinct challenges of diagnosing cerebral vasospasm in the setting of severe traumatic brain injury.

The use of transcranial Doppler ultrasound in confirming brain death in the setting of skull defects and extraventricular drains.

BACKGROUND: Transcranial Doppler ultrasound (TCD) has been used as a confirmatory test for the diagnosis of brain death (BD), but may be inaccurate in patients with a skull defect or extraventricular drain (EVD). METHODS AND RESULTS: We report three cases of patients with a skull defect or EVD in whom TCD supported a diagnosis of BD but in which the clinical examination later refuted the diagnosis. CONCLUSION: We caution against the use of TCD to confirm the diagnosis of BD in the presence of a skull defect or EVD.

Single-cell genetic analysis reveals the composition of initiating clones and phylogenetic patterns of branching and parallel evolution in myeloma.

Although intratumor heterogeneity has been inferred in multiple myeloma (MM), little is known about its subclonal phylogeny. To describe such phylogenetic trees in a series of patients with MM, we perform whole-exome sequencing and single-cell genetic analysis. Our results demonstrate that at presentation myeloma is composed of two to six different major clones, which are related by linear and branching phylogenies. Remarkably, the earliest myeloma-initiating clones, some of which only had the initiating t(11;14), were still present at low frequencies at the time of diagnosis. For the first time in myeloma, we demonstrate parallel evolution whereby two independent clones activate the RAS/MAPK pathway through RAS mutations and give rise subsequently to distinct subclonal lineages. We also report the co-occurrence of RAS and interferon regulatory factor 4 (IRF4) p.K123R mutations in 4% of myeloma patients. Lastly, we describe the fluctuations of myeloma subclonal architecture in a patient analyzed at presentation and relapse and in NOD/SCID-IL2Rγ(null) xenografts, revealing clonal extinction and the emergence of new clones that acquire additional mutations. This study confirms that myeloma subclones exhibit different survival properties during treatment or mouse engraftment. We conclude that clonal diversity combined with varying selective pressures is the essential foundation for tumor progression and treatment resistance in myeloma.