Time course and correlates of psychological distress post spinal surgery: A longitudinal study.

Background: Psychological distress post lumbar spine surgery is associated with poorer outcomes. There is a scarcity of studies devoted to analyzing the risk factors associated with psychological distress in patients who have undergone lumbar fusion surgery. The purpose of this study was to (1) describe the time course and severity of psychological distress using the STarT Back Tool (SBT) and (2) determine the demographic and clinical predictors of SBT score post lumbar spine fusion surgery. Methods: This retrospective longitudinal study analyzed 227 subjects with 1- and 2-level lumbar fusion surgery who underwent standardized assessment preoperatively and at 4 and 12 weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Postoperative psychological distress was measured by self-reported SBT. Risk factors for SBT over time were identified using ordinal and mixed-effects modelling. Results: Although the trajectory of SBT levels declined postoperatively over time, at week-12, 20% of patients had moderate to high SBT. Postoperative SBT scores at week-4 time point was significantly greater than SBT scores at week-8 (OR = 2.7, 95% credible interval [CrI]; 1.8-3.9). Greater SBT scores at week-4 were strongly associated with greater SBT scores throughout 12 weeks of follow-up (OR = 7.3, [95% CrI; 1.2-31.4]). Greater postoperative SBT levels over time were associated with being male (OR = 2.2, 95% CrI; 1.0-3.9), greater preoperative back or leg pain intensity (OR = 2.2; 95% CrI: 1.0-4.4), greater preoperative leg weakness (OR = 4.2, 95% CrI: 1.7-7.5) and higher preoperative depression levels (OR = 4.8; 95% CrI: 1.6-10.4). Conclusion: Postoperative SBT levels declined nonlinearly over time. However, a sizable proportion of patients had moderate to high psychological distress at week-12 postsurgery. Greater preoperative back or leg pain intensity, leg weakness and depression levels, and male gender were risk factors of greater psychological distress postsurgery. Although requiring validation, our study has identified potential modifiable risk factors which may give an opportunity to provide early (preoperative) and targeted strategies to optimize postoperative psychosocial outcomes in patients undergoing lumbar fusion surgeries.

A Contemporary Analysis of Closed Claims Related to Wrong-Site Surgery.

BACKGROUND: Wrong-site surgeries are considered "never events" and continue to occur despite the implementation of the Universal Protocol by The Joint Commission in 2003. METHODS: The authors reviewed closed claims data on wrong-site surgery between 2013 and 2020 from a medical malpractice company. The claims were classified by allegations made by claimants, the responsible services, the types of procedures, the injuries, and contributing factors. Researchers performed a descriptive analysis of the available variables and reviewed the clinical summary of each case. RESULTS: Between 2013 and 2020, there were 68 wrong-site closed claims cases. The mean age of the patients was 55.7 (standard deviation 16.21) years, and 51.5% were female. The services most frequently responsible for these were Orthopedic (35.3%), Neurosurgery (22.1%), and Urology (8.8%). The most common types of procedures were spine and intervertebral disc surgery (22.1%), arthroscopy (14.7%), and surgery on muscles/tendons (11.8%). The severity of claims was higher in the inpatient setting compared to the ambulatory setting. The most common alleged injuries included the need for additional surgery (45.6%), pain (33.8%), mobility dysfunction (10.3%), worsened injury (8.8%), death (7.4%), and total loss (7.4%). The top contributing factors to wrong-site surgery were failure to follow policy/protocol (83.8%) and failure to review the medical records (41.2%). The mean closed claim value was $136,452.84, and 60.3% of cases were settled. CONCLUSION: The risk of wrong-site surgeries is increased with spine surgeries, likely due to unique technical challenges. Further research is required to identify effective methods of prevention of these events.

Patient falls in the operating room setting: An analysis of reported safety events.

INTRODUCTION: Patient falls are a preventable public health problem, and they are among the most reported safety incidents in the hospital. We used a hospital safety reporting system to examine the nature of reported falls in the perioperative setting at an academic tertiary center. METHODS: In this retrospective study, reports of perioperative safety events listed as "Falls" between 2014 and 2020 were analyzed for severity level and specific event type. RESULTS: Out of 8337 safety reports from 2014 to 2020, 86 were "fall" related (1%). The most common "fall" event type was "ambulating with assistance and the severity level reported was mainly level 1 (no harm, did reach patient, 63%) followed by level 2 (temporary or minor harm, 28%). One of the most frequently reported types of perioperative falls was from a bed or stretcher (15% of falls)". CONCLUSIONS: Our safety data reporting system identified falls as a safety event that causes patient harm in the perioperative setting that could be preventable with a multifaceted interdisciplinary approach. Risk managers can use these data to implement strategies to reduce falls such as creating screening protocols to identify high-risk patients, educating and training healthcare personnel, and optimizing operating room, hospital, and equipment design.

Factors Associated with Pain Intensity and Walking Disability After Lumbar Fusion: A Longitudinal Study.

STUDY DESIGN: Retrospective longitudinal study. OBJECTIVE: To identify the preoperative factors associated with postoperative lumbar fusion recovery in back or leg pain, self-reported walking time, and gait speed over a 6-month period. SUMMARY OF BACKGROUND DATA: The demand for lumbar fusion surgeries has significantly increased over the years. Yet, some patients report persistent postsurgical pain and poor functional outcomes. Unfortunately, the associated risk factors are not well understood. METHODS: The study analyzed 232 subjects with mono- or bisegmental lumbar fusion surgery who underwent standardized assessment preoperatively and at 4, 12, and 24weeks postoperatively. Preoperative variables collected were demographic, clinical, and psychological variables. Back or leg pain was measured by the Numeric Pain Rating Scale. Walking disability was measured by self-reported walking time and performance-based fast gait speed. Risk factors of pain and walking disability over time were identified using ordinal and linear mixed-effects modeling. RESULTS: At 6 months post-surgery, 17% of patients reported having moderate or severe back/leg pain and 24% were unable to walk longer than 30 minutes. Greater preoperative self-reported leg weakness frequency and body-mass-index (BMI) were strongly associated with greater pain and walking disability. Additionally, greater preoperative depression symptoms were associated with greater back/leg pain (adjusted odds ratio = 4.0) and shorter walking time (adjusted odds ratio = 2.7)-but not with slower gait speed (difference = 0.01 m/s). Old age and female gender were strongly associated with gait speed but not with self-reported walking time. CONCLUSION: A sizable proportion of patients had poor pain and walking outcomes even at 6 months post-surgery. Preoperative leg weakness and BMI were consistent risk factors and patients with greater depression symptoms may have poorer self-reported outcomes. Although requiring validation, our study has identified potentially modifiable risk factors which may give clinicians an opportunity to provide early (preoperative) and targeted intervention strategies to optimize postoperative outcomes.Level of Evidence: NA.

Post-COVID-19 paediatric inflammatory multisystem syndrome: association of ethnicity, key worker and socioeconomic status with risk and severity.

OBJECTIVES: Patients from ethnic minority groups and key workers are over-represented among adults hospitalised or dying from COVID-19. In this population-based retrospective cohort, we describe the association of ethnicity, socioeconomic and family key worker status with incidence and severity of Paediatric Inflammatory Multisystem Syndrome Temporally associated with SARS-CoV-2 (PIMS-TS). SETTING: Evelina London Children's Hospital (ELCH), the tertiary paediatric hospital for the South Thames Retrieval Service (STRS) region. PARTICIPANTS: 70 children with PIMS-TS admitted 14 February 2020-2 June 2020. OUTCOME MEASURES: Incidence and crude ORs are presented, comparing ethnicity and socioeconomic status of our cohort and the catchment population, using census data and Index of Multiple Deprivation (IMD). Regression is used to estimate the association of ethnicity and IMD with admission duration and requirement for intensive care, inotropes and ventilation. RESULTS: Incidence was significantly higher in children from black (25.0 cases per 100 000 population), Asian (6.4/100 000) and other (17.8/100 000) ethnic groups, compared with 1.6/100 000 in white ethnic groups (ORs 15.7, 4.0 and 11.2, respectively). Incidence was higher in the three most deprived quintiles compared with the least deprived quintile (eg, 8.1/100 000 in quintile 1 vs 1.6/100 000 in quintile 5, OR 5.2). Proportions of families with key workers (50%) exceeded catchment proportions. Admission length of stay was 38% longer in children from black ethnic groups than white (95% CI 4% to 82%; median 8 days vs 6 days). 9/10 children requiring ventilation were from black ethnic groups. CONCLUSIONS: Children in ethnic minority groups, living in more deprived areas and in key worker families are over-represented. Children in black ethnic groups had longer admissions; ethnicity may be associated with ventilation requirement.This project was registered with the ELCH audit and service evaluation team, ref. no 11186.

The Association of Dexmedetomidine on Perioperative Opioid Consumption in Children Undergoing Adenotonsillectomy With and Without Obstructive Sleep Apnea.

BACKGROUND: Dexmedetomidine is used to reduce opioid consumption in pediatric anesthesia. However, there is conflicting evidence in pediatric adenotonsillectomy literature regarding the total perioperative opioid-sparing effects of dexmedetomidine. The aim of this study was to examine the association between dexmedetomidine and total perioperative opioid consumption in children undergoing adenotonsillectomy. METHODS: This was a retrospective cohort study of the children undergoing adenotonsillectomy surgery at Texas Children's Hospital between November 2017 and October 2018. Intraoperative dexmedetomidine was the exposure of interest. The primary outcome was total perioperative opioid consumption calculated as oral morphine equivalents (OME). Secondary outcomes of interest included opioid consumption and pain scores based on presence and absence of obstructive sleep apnea (OSA) and postanesthesia care unit (PACU) duration. We used multivariable linear regression to estimate the association of dexmedetomidine on the outcomes. RESULTS: A total of 941 patients met inclusion criteria, 697 (74.1%) received intraoperative dexmedetomidine. For every 0.1 µg/kg increase in intraoperative dexmedetomidine, the total perioperative OME (mg/kg) decreases by 0.021 mg/kg (95% CI, -0.027 to -0.015; P < .001). Pain scores did not significantly vary by OSA status. PACU duration increased by 1.14 minutes (95% CI, 0.30-1.99; P = .008) for each 0.1 µg/kg of intraoperative dexmedetomidine. CONCLUSIONS: Dexmedetomidine is associated with an overall perioperative opioid-sparing effect in children undergoing adenotonsillectomy and a small but statistically significant increase in PACU duration. Additionally, children with OSA did not have reduced perioperative opioid consumption.

Hybridization Chain Reactions Targeting the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2).

In this work, hybridization chain reactions (HCRs) toward Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) nucleocapsid phosphoproteins gene loci and human RNase P are proposed to provide an isothermal amplification screening tool. The proposed chain reactions target the complementary DNA (cDNA) of SARS-CoV-2, with loci corresponding to gold-standard polymerase chain reaction (PCR) loci. Four hybridization chain reaction reactions are demonstrated herein, targeting N1/N2/N3 loci and human RNase P. The design of the hybridization chain reaction, herein, is assisted with an algorithm. The algorithm helps to search target sequences with low local secondary structure and high hybridization efficiency. The loop domain of the fuel hairpin molecule H1 and H2, which are the tunable segments in such reactions, are used as an optimization parameter to improve the hybridization efficiency of the chain reaction. The algorithm-derived HCR reactions were validated with gel electrophoresis. All proposed reactions exhibit a hybridization complex with a molecular mass >1.5k base pairs, which is clear evidence of chain reaction. The hybridization efficiency trend revealed by gel electrophoresis corresponds nicely to the simulated data from the algorithm. The HCR reactions and the corresponding algorithm serve as a basis to further SARS-CoV-2 sensing applications and facilitate better screening strategies for the prevention of on-going pandemics.

An Instrumented Pull Test to Characterize Postural Responses.

Impairment of postural reflexes, termed postural instability, is a common and disabling deficit in Parkinson's disease. To assess postural reflexes, clinicians typically employ the pull test to grade corrective responses to a backward perturbation at the shoulders. However, the pull test is prone to issues with reliability and scaling (score/4). Here, we present an instrumented version of the pull test to more precisely quantify postural responses. Akin to the clinical test, pulls are manually administered except pull force is also recorded. Displacements of the trunk and feet are captured by a semi-portable motion tracking system. Raw data represent distance traveled (in millimeter units), making subsequent interpretation and analysis intuitive. The instrumented pull test also detects variabilities influencing pull test administration, such as pull force, thereby identifying and quantifying potential confounds that can be accounted for by statistical techniques. The instrumented pull test could have application in studies seeking to capture early abnormalities in postural responses, track postural instability over time, and detect responses to therapy.

Prognostic Value of Nodal Response After Preoperative Treatment of Gastric Adenocarcinoma.

Background: Pathologically positive lymph nodes (ypN+) after preoperative chemotherapy are associated with poor survival in patients with gastric cancer. Little is known about the association between response to preoperative therapy and the benefit of postoperative therapy. Methods: This retrospective cohort study of the National Cancer Database included patients with clinically node-positive (cN+) gastric cancer treated with preoperative therapy followed by surgery (2006-2014). Preoperative treatment modality was categorized as the inclusion of radiation therapy (RT) or chemotherapy alone. Pretreatment clinical and pathologic stages were used to determine pathologic treatment response rates. The association between overall risk of death and preoperative treatment, disease response, and adjuvant therapy use was evaluated using multivariable Cox regression. Results: Preoperative RT was used in 53.6% of 1,976 patients with cN+ gastric cancer, (74.3% cardia and 10.1% noncardia). The nodal response rate was 38.9% and was higher with RT than with chemotherapy alone (cardia, 46.0% vs 29.1%; P<.001; noncardia, 43.8% vs 31.9%; P=.06). Preoperative RT was associated with an approximate 2-fold increase in the odds of pathologic response compared with chemotherapy. Overall, use of adjuvant therapy was not associated with a decreased risk of death. A primary tumor response with residual nodal disease was not associated with survival (hazard ratio [HR], 1.03; 95% CI, 0.66-1.60). However, a nodal response with residual primary disease was significantly associated with survival (HR, 0.54; 95% CI, 0.44-0.65). Conclusions: More than one-third of node-positive gastric cancers showed pathologic nodal response with preoperative treatment. RT is associated with a higher response than chemotherapy. Patients with ypN+ disease have worse survival, regardless of whether they receive postoperative therapy. Future gastric cancer trials should evaluate the role of preoperative RT and individualize postoperative therapy use.

A palm-worn device to quantify rigidity in Parkinson's disease.

BACKGROUND: Parkinsonian rigidity is identified on clinical examination as resistance to passive movement. Measurement of rigidity commonly relies on ordinal rating scales (MDS-UPDRS), however instrumented objective measures may provide greater mechanistic insight. NEW METHOD: We present a palm-worn instrument to objectively quantify rigidity on a continuous scale. The device employs a miniature motor to flex the third digit of the hand about the metacarpophalangeal joint whilst transducers record flexion/extension forces. We aim to determine congruence with the MDS-UPDRS, investigate sensitivity to the impact of deep brain stimulation (DBS) and contralateral movement, and make comparisons with healthy individuals. Eight participants with Parkinson's disease underwent evaluation during conditions: on and off DBS, and with and without contralateral limb movement to activate rigidity. During each DBS condition, wash-in/out effects were tracked using both our instrument and two blinded clinical raters. Sixteen healthy volunteers (age-matched/young) served as controls. RESULTS: Rigidity measured using our instrument had moderate agreement with the MDS-UPDRS and showed differences between therapeutic state, activation conditions, and disease/healthy cohorts. Rigidity gradually worsened over a one-hour period after DBS cessation, but improved more rapidly with DBS resumption. COMPARISON WITH EXISTING METHODS: Previous attempts to quantify rigidity include manual approaches where a clinician is required to manipulate limbs while sensors passively gather information, or large automated instruments to move the wrist or elbow. CONCLUSION: Given its ability to track changes in rigidity due to therapeutic intervention, our technique could have applications where continuous measurement is required or where a suitably qualified rater is absent.

Objective evaluation of bradykinesia in Parkinson's disease using an inexpensive marker-less motion tracking system.

OBJECTIVE: Quantification of bradykinesia (slowness of movement) is crucial for the treatment and monitoring of Parkinson's disease. Subjective observational techniques are the de-facto 'gold standard', but such clinical rating scales suffer from poor sensitivity and inter-rater variability. Although various technologies have been developed for assessing bradykinesia in recent years, most still require considerable expertise and effort to operate. Here we present a novel method to utilize an inexpensive off-the-shelf hand-tracker (Leap Motion) to quantify bradykinesia. APPROACH: Eight participants with Parkinson's disease receiving benefit from deep brain stimulation were recruited for the study. Participants were assessed 'on' and 'off' stimulation, with the 'on' condition repeated to evaluate reliability. Participants performed wrist pronation/supination, hand open/close, and finger-tapping tasks during each condition. Tasks were simultaneously captured by our software and rated by three clinicians. A linear regression model was developed to predict clinical scores and its performance was assessed with leave-one-subject-out cross validation. MAIN RESULTS: Aggregate bradykinesia scores predicted by our method were in strong agreement (R = 0.86) with clinical scores. The model was able to differentiate therapeutic states and comparison between the test-retest conditions yielded no significant difference (p  = 0.50). SIGNIFICANCE: These findings demonstrate that our method can objectively quantify bradykinesia in agreement with clinical observation and provide reliable measurements over time. The hardware is readily accessible, requiring only a modest computer and our software to perform assessments, thus making it suitable for both clinic- and home-based symptom tracking.

Neurophysiological analysis of the clinical pull test.

Postural reflexes are impaired in conditions such as Parkinson's disease, leading to difficulty walking and falls. In clinical practice, postural responses are assessed using the "pull test," where an examiner tugs the prewarned standing patient backward at the shoulders and grades the response. However, validity of the pull test is debated, with issues including scaling and variability in administration and interpretation. It is unclear whether to assess the first trial or only subsequent repeated trials. The ecological relevance of a forewarned backward challenge is also debated. We therefore developed an instrumented version of the pull test to characterize responses and clarify how the test should be performed and interpreted. In 33 healthy participants, "pulls" were manually administered and pull force measured. Trunk and step responses were assessed with motion tracking. We probed for the StartReact phenomenon (where preprepared responses are released early by a startling stimulus) by delivering concurrent normal or "startling" auditory stimuli. We found that the first pull triggers a different response, including a larger step size suggesting more destabilization. This is consistent with "first trial effects," reported by platform translation studies, where movement execution appears confounded by startle reflex-like activity. Thus, first pull test trials have clinical relevance and should not be discarded as practice. Supportive of ecological relevance, responses to repeated pulls exhibited StartReact, as previously reported with a variety of other postural challenges, including those delivered with unexpected timing and direction. Examiner pull force significantly affected the postural response, particularly the size of stepping. NEW & NOTEWORTHY We characterized postural responses elicited by the clinical "pull test" using instrumentation. The first pull triggers a different response, including a larger step size suggesting more destabilization. Thus, first trials likely have important clinical and ecological relevance and should not be discarded as practice. Responses to repeated pulls can be accelerated with a startling stimulus, as reported with a variety of other challenges. Examiner pull force was a significant factor influencing the postural response.

Balance control systems in Parkinson's disease and the impact of pedunculopontine area stimulation.

Impaired balance is a major contributor to falls and diminished quality of life in Parkinson's disease, yet the pathophysiology is poorly understood. Here, we assessed if patients with Parkinson's disease and severe clinical balance impairment have deficits in the intermittent and continuous control systems proposed to maintain upright stance, and furthermore, whether such deficits are potentially reversible, with the experimental therapy of pedunculopontine nucleus deep brain stimulation. Two subject groups were assessed: (i) 13 patients with Parkinson's disease and severe clinical balance impairment, implanted with pedunculopontine nucleus deep brain stimulators; and (ii) 13 healthy control subjects. Patients were assessed in the OFF medication state and blinded to two conditions; off and on pedunculopontine nucleus stimulation. Postural sway data (deviations in centre of pressure) were collected during quiet stance using posturography. Intermittent control of sway was assessed by calculating the frequency of intermittent switching behaviour (discontinuities), derived using a wavelet-based transformation of the sway time series. Continuous control of sway was assessed with a proportional-integral-derivative (PID) controller model using ballistic reaction time as a measure of feedback delay. Clinical balance impairment was assessed using the 'pull test' to rate postural reflexes and by rating attempts to arise from sitting to standing. Patients with Parkinson's disease demonstrated reduced intermittent switching of postural sway compared with healthy controls. Patients also had abnormal feedback gains in postural sway according to the PID model. Pedunculopontine nucleus stimulation improved intermittent switching of postural sway, feedback gains in the PID model and clinical balance impairment. Clinical balance impairment correlated with intermittent switching of postural sway (rho = - 0.705, P < 0.001) and feedback gains in the PID model (rho = 0.619, P = 0.011). These results suggest that dysfunctional intermittent and continuous control systems may contribute to the pathophysiology of clinical balance impairment in Parkinson's disease. Clinical balance impairment and their related control system deficits are potentially reversible, as demonstrated by their improvement with pedunculopontine nucleus deep brain stimulation.

Clinical validation of a precision electromagnetic tremor measurement system in participants receiving deep brain stimulation for essential tremor.

Tremor is characterized commonly through subjective clinical rating scales. Accelerometer-based techniques for objective tremor measurement have been developed in the past, yet these measures are usually presented as an unintuitive dimensionless index without measurement units. Here we have developed a tool (TREMBAL) to provide quantifiable and objective measures of tremor severity using electromagnetic motion tracking. We aimed to compare TREMBAL's objective measures with clinical tremor ratings and determine the test-retest reliability of our technique. Eight participants with ET receiving deep brain stimulation (DBS) therapy were consented. Tremor was simultaneously recorded using TREMBAL and video during DBS adjustment. After each adjustment, participants performed a hands-outstretched task (for postural tremor) and a finger-nose task (for kinetic tremor). Video recordings were de-identified, randomized, and shown to a panel of movement disorder specialists to obtain their ratings. Regression analysis and Pearson's correlations were used to determine agreement between datasets. Subsets of the trial were repeated to assess test-retest reliability. Tremor amplitude and velocity measures were in close agreement with mean clinical ratings (r > 0.90) for both postural and kinetic tremors. Test-retest reliability for both translational and rotational components of tremor showed intra-class correlations >0.80. TREMBAL assessments showed that tremor gradually improved with increasing DBS therapy-this was also supported by clinical observation. TREMBAL measurements are a sensitive, objective and reliable assessment of tremor severity. This tool may have application in clinical trials and in aiding automated optimization of deep brain stimulation.

EZH2 phosphorylation by JAK3 mediates a switch to noncanonical function in natural killer/T-cell lymphoma.

The best-understood mechanism by which EZH2 exerts its oncogenic function is through polycomb repressive complex 2 (PRC2)-mediated gene repression, which requires its histone methyltransferase activity. However, small-molecule inhibitors of EZH2 that selectively target its enzymatic activity turn out to be potent only for lymphoma cells with EZH2-activating mutation. Intriguingly, recent discoveries, including ours, have placed EZH2 into the category of transcriptional coactivators and thus raised the possibility of noncanonical signaling pathways. However, it remains unclear how EZH2 switches to this catalytic independent function. In the current study, using natural killer/T-cell lymphoma (NKTL) as a disease model, we found that phosphorylation of EZH2 by JAK3 promotes the dissociation of the PRC2 complex leading to decreased global H3K27me3 levels, while it switches EZH2 to a transcriptional activator, conferring higher proliferative capacity of the affected cells. Gene expression data analysis also suggests that the noncanonical function of EZH2 as a transcriptional activator upregulates a set of genes involved in DNA replication, cell cycle, biosynthesis, stemness, and invasiveness. Consistently, JAK3 inhibitor was able to significantly reduce the growth of NKTL cells, in an EZH2 phosphorylation-dependent manner, whereas various compounds recently developed to inhibit EZH2 methyltransferase activity have no such effect. Thus, pharmacological inhibition of JAK3 activity may provide a promising treatment option for NKTL through the novel mechanism of suppressing noncanonical EZH2 activity.

Deregulated MIR335 that targets MAPK1 is implicated in poor outcome of paediatric acute lymphoblastic leukaemia.

Acute lymphoblastic leukaemia (ALL) is the most common paediatric malignancy. Although 90% of patients are now long-term survivors, the remaining 10% have poor outcome predominantly due to drug resistance. In this study, we carried out genome-wide microRNA (miRNA) microarray analysis on diagnostic bone marrow samples to determine miRNA expression profiles associated with poor outcome in ALL. A reduced expression of MIR335 was identified as the most significant miRNA abnormality associated with poor outcome. It is well known that glucocorticoid (GC) resistance is one of the major reasons contributing to poor outcome. We show that exogenous expression of MIR335 in ALL cells increases sensitization to prednisolone-mediated apoptosis. Moreover, we demonstrate that MAPK1 is a novel target of MIR335, and that MEK/ERK inhibitor treatment enhanced prednisolone-induced cell death through the activation of BIM (BCL2L11). These results provide a possible underlying molecular mechanism to explain the association between reduced MIR335 with poor clinical outcome, and suggest that approaches to re-introduce MIR335 expression or override MAPK1 activity may offer promising therapeutic strategies in the treatment of ALL.

EZH2 overexpression in natural killer/T-cell lymphoma confers growth advantage independently of histone methyltransferase activity.

The role of enhancer of zeste homolog 2 (EZH2) in cancer is complex and may vary depending on the cellular context. We found that EZH2 is aberrantly overexpressed in the majority of natural killer/T-cell lymphoma (NKTL), an aggressive lymphoid malignancy with very poor prognosis. We show that EZH2 upregulation is mediated by MYC-induced repression of its regulatory micro RNAs and EZH2 exerts oncogenic properties in NKTL. Ectopic expression of EZH2 in both primary NK cells and NKTL cell lines leads to a significant growth advantage. Conversely, knock-down of EZH2 in NKTL cell lines results in cell growth inhibition. Intriguingly, ectopic EZH2 mutant deficient for histone methyltransferase activity is also able to confer growth advantage and rescue growth inhibition on endogenous EZH2 depletion in NKTL cells, indicating an oncogenic role of EZH2 independent of its gene-silencing activity. Mechanistically, we show that EZH2 directly promotes the transcription of cyclin D1 and this effect is independent of its enzymatic activity. Furthermore, depletion of EZH2 using a PRC2 inhibitor 3-deazaneplanocin A significantly inhibits growth of NK tumor cells. Therefore, our study uncovers an oncogenic role of EZH2 independent of its methyltransferase activity in NKTL and suggests that targeting EZH2 may have therapeutic usefulness in this lymphoma.

Dysregulated microRNAs affect pathways and targets of biologic relevance in nasal-type natural killer/T-cell lymphoma.

We performed a comprehensive genome-wide miRNA expression profiling of extranodal nasal-type natural killer/T-cell lymphoma (NKTL) using formalin-fixed paraffin-embedded tissue (n = 30) and NK cell lines (n = 6) compared with normal NK cells, with the objective of understanding the pathogenetic role of miRNA deregulation in NKTL. Compared with normal NK cells, differentially expressed miRNAs in NKTL are predominantly down-regulated. Re-expression of down-regulated miRNAs, such as miR-101, miR-26a, miR26b, miR-28-5, and miR-363, reduced the growth of the NK cell line and modulated the expression of their predicted target genes, suggesting the potential functional role of the deregulated miRNAs in the oncogenesis of NKTL. Taken together, the predicted targets whose expression is inversely correlated with the expression of deregulated miRNA in NKTL are significantly enriched for genes involved in cell cycle-related, p53, and MAPK signaling pathways. We also performed immunohistochemical validation for selected target proteins and found overexpression of MUM1, BLIMP1, and STMN1 in NKTL, and notably, a corresponding increase in MYC expression. Because MYC is known to cause repression of miRNA expression, it is possible that MYC activation in NKTL may contribute to the suppression of the miRNAs regulating MUM1, BLIMP1, and STMN1.

Inhibition of KATP channels in the rat tail artery by neurally released noradrenaline acting on postjunctional alpha2-adrenoceptors.

In rat tail artery, activation of postjunctional alpha(2)-adrenoceptors by noradrenaline (NA) released from sympathetic axons produces a slow depolarization (NAD) of the smooth muscle through a decrease in K(+) conductance. In this study we used intracellular recording to investigate whether the K(+) channel involved is the ATP-sensitive K(+) (K(ATP)) channel. Changes in membrane resistance were monitored by measuring the time constant of decay of excitatory junction potentials. The K(ATP) channel blockers, glibenclamide (10 microm) and PNU 37883A (5 microm), depolarized the smooth muscle and increased membrane resistance. Conversely, the K(ATP) channel openers, pinacidil (0.1 and 0.5 microm) and levcromakalim (0.1 microm), hyperpolarized the smooth muscle and decreased membrane resistance. Activation of K(ATP) channels with calcitonin gene-related peptide (CGRP; 10 nM) also hyperpolarized the smooth muscle and decreased membrane resistance. The NAD was abolished by both glibenclamide and PNU 37883A but was potentiated by CGRP. However, unlike CGRP, the directly acting K(ATP) channel openers, pinacidil and levcromakalim, inhibited the NAD. The effects of other K(+) channel blockers were also determined. A high concentration of Ba(2+)(1 mM), which would be expected to block K(ATP) channels, abolished the NAD, whereas teteraethylammonium (1 mM) and 4-aminopyridine (1 mM) increased its amplitude. Apamin (0.5 microm) and a lower concentration of Ba(2+) (0.1 mM) did not affect the NAD. These findings indicate that activation of alpha(2)-adrenoceptors by neurally released NA depolarizes the membrane of vascular smooth muscle by inhibiting K(ATP) channels open in the resting membrane.

Cbp deficiency alters Csk localization in lipid rafts but does not affect T-cell development.

The ubiquitously expressed transmembrane adaptor Csk-binding protein (Cbp) recruits Csk to lipid rafts, where the latter exerts its negative regulatory effect on the Src family of protein tyrosine kinases. We have inactivated Cbp in the mouse germ line. In contrast to Csk gene inactivation, which leads to embryonic lethality and impaired T-cell development, Cbp-deficient mice were viable and exhibited normal T-cell development but with an increased thymocyte population. In the absence of Cbp, the amount of Csk that localizes to the lipid rafts was greatly reduced. Interestingly, this altered lipid raft localization of Csk did not lead to any detectable biochemical or functional defect in T cells. The T-cell receptor-induced intracellular calcium flux, cell proliferation, and cytokine secretion were not affected by the absence of Cbp. Peripheral T-cell tolerance to superantigen SEB was also largely intact in Cbp-deficient mice. Thus, Cbp is dispensable for T-cell development and activation.