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P1.01-75 Utility of cfDNA Testing for Acquired Resistance: The Memorial Sloan Kettering Experience with Plasma EGFR T790M Clinical Testing. J Thorac Oncol 2018. [DOI: 10.1016/j.jtho.2018.08.631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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OA 14.05 Phase 2 Basket Trial of Ado-Trastuzumab Emtansine in Patients with HER2 Mutant or Amplified Lung Cancers. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.09.410] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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OA 10.05 Non-Invasive Molecular Profiling in NSCLC by Targeted and Whole Exome Analysis of Plasma cfDNA. J Thorac Oncol 2017. [DOI: 10.1016/j.jtho.2017.09.385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Association Of Plasma And Urinary Mutant DNA With Clinical Outcomes In Muscle Invasive Bladder Cancer. Sci Rep 2017; 7:5554. [PMID: 28717136 PMCID: PMC5514073 DOI: 10.1038/s41598-017-05623-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 05/31/2017] [Indexed: 01/06/2023] Open
Abstract
Muscle Invasive Bladder Cancer (MIBC) has a poor prognosis. Whilst patients can achieve a 6% improvement in overall survival with Neo-Adjuvant Chemotherapy (NAC), many do not respond. Body fluid mutant DNA (mutDNA) may allow non-invasive identification of treatment failure. We collected 248 liquid biopsy samples including plasma, cell pellet (UCP) and supernatant (USN) from spun urine, from 17 patients undergoing NAC. We assessed single nucleotide variants and copy number alterations in mutDNA using Tagged-Amplicon- and shallow Whole Genome- Sequencing. MutDNA was detected in 35.3%, 47.1% and 52.9% of pre-NAC plasma, UCP and USN samples respectively, and urine samples contained higher levels of mutDNA (p = <0.001). Longitudinal mutDNA demonstrated tumour evolution under the selective pressure of NAC e.g. in one case, urine analysis tracked two distinct clones with contrasting treatment sensitivity. Of note, persistence of mutDNA detection during NAC predicted disease recurrence (p = 0.003), emphasising its potential as an early biomarker for chemotherapy response.
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2. Antecollis associated with Parkinson’s disease improved following apomorphine therapy. Clin Neurophysiol 2016. [DOI: 10.1016/j.clinph.2015.11.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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The HIV Workforce in New York State: Does Patient Volume Correlate with Quality? Clin Infect Dis 2015; 61:1871-7. [PMID: 26423383 DOI: 10.1093/cid/civ719] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 07/19/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Knowledge of care practices among clinicians who annually treat <20 human immunodeficiency virus (HIV)-positive patients with antiretroviral therapy (ART) is insufficient, despite their number, which is likely to increase given shifting healthcare policies. We analyze the practices, distribution and quality of care provided by low-volume prescribers (LVPs) based on available data sources in New York State. METHODS We communicated with 1278 (66%) of the LVPs identified through a statewide claims database to determine the circumstances under which they prescribed ART in federal fiscal year 2009. We reviewed patient records from 84 LVPs who prescribed ART routinely and compared their performance with that of experienced clinicians practicing in established HIV programs. RESULTS Of the surveyed LVPs, 368 (29%) provided routine ambulatory care for 2323 persons living with HIV/AIDS, and 910 LVPs cited other reasons for prescribing ART. Although the majority of LVPs (73%) practiced in New York City, patients living upstate were more likely to be cared for by a LVP (odds ratio, 1.7; 95% confidence interval, 1.4-1.9). Scores for basic HIV performance measures, including viral suppression, were significantly higher in established HIV programs than for providers who wrote prescriptions for <20 persons living with HIV/AIDS (P < .01). We estimate that 33% of New York State clinicians who provide ambulatory HIV care are LVPs. CONCLUSIONS Our findings suggest that the quality of care associated with providers who prescribe ART for <20 patients is lower than that provided by more experienced providers. Access to experienced providers as defined by patient volume is an important determinant of delivering high-quality care and should guide HIV workforce policy decisions.
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58: Proffered Paper: Noninvasive monitoring of tumour mutations and dynamics in circulating DNA of non-small cell lung cancer patients treated with EGFR inhibitors. Eur J Cancer 2014. [DOI: 10.1016/s0959-8049(14)50058-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Combined Spine Conference of the Canadian Spine Society New Zealand Orthopaedic Spine Society, Spine Society of Australia: Fairmont Château Lake Louise, Lake, Louise, Alberta, Tuesday, Feb. 25 to Saturday, Mar. 1, 20141.1.01 The use of suspension radiographs to predict LIV tilt.1.1.02 Surgical correction of adolescent idiopathic scoliosis without fusion: an animal model.1.1.03 Are full torso surface topography postural measurements more sensitive to change than back only parameters in adolescents with idiopathic scoliosis and a main thoracic curve?1.2.04 Restoration of thoracic kyphosis in adolescent idiopathic kyphosis: comparative radiographic analysis of round versus rail rods.1.2.05 Scoliosis surgery in spastic quadriplegic cerebral palsy: Is fusion to the pelvis always necessary? A 4–18-year follow-up study.1.2.06 Identification and validation of pain-related biomarkers surrounding spinal surgery in adolescents.1.3.07 Cervical sagittal deformity develops after PJK in adult throacolumbar deformity correction: radiographic analysis using a novel global sagittal angular parameter, the CTPA.1.3.08 Impact of obesity on complications and patient-reported outcomes in adult spinal deformity surgery.1.3.09 The T1 pelvic angle, a novel radiographic measure of sagittal deformity, accounts for both pelvic retroversion and truncal inclination and correlates strongly with HRQOL.1.4.10 Determining cervical sagittal deformity when it is concurrent with thoracolumbar deformity.1.4.11 The influence of sagittal balance and pelvic parameters on the outcome of surgically treated patients with degenerative spondylolisthesis.1.4.12 Predictors of degenerative spondylolisthesis and loading translation in surgical lumbar spinal stenosis patients.2.1.13 Mechanical allodynia following disc herniation requires intraneural macrophage infiltration and can be blocked by systemic selenium delivery or attenuation of BDNF activity.2.1.14 The effect of alanyl-glutamine on epidural fibrosis in a rat laminectomy model.2.1.15 Anterior lumbar interbody fusion using recombinant human bone morphogenetic protein-2: a prospective study of complications.2.2.16 2-year results of a Canadian, multicentre, blinded, pilot study of a novel peptide in promoting lumbar spine fusion.2.2.17 Comparative outcomes and cost-utility following surgical treatment of focal lumbar spinal stenosis compared with osteoarthritis of the hip or knee: long-term change in health-related quality of life.2.2.18 Changes in objectively measured walking performance, function, and pain following surgery for spondylolisthesis and lumbar spinal stenosis.2.3.19 A prospective multicentre observational data-monitored study of minimally invasive fusion to treat degenerative lumbar disorders: complications and outcomes at 1-year follow-up.2.3.20 Assessment and classification of subsidence in lateral interbody fusion using serial computed tomography.2.3.21 Predictors of willingness to undergo spinal and orthopaedic surgery after surgical consultation.2.4.22 Indirect foraminal decompression is independent of facet arthropathy in extreme lateral interbody fusion.2.4.23 Cervical artificial disc replacement with ProDisc-C: clinical and radiographic outcomes with long-term follow-up.2.4.24 Tantalum trabecular metal implants in anterior cervical corpectomy and fusion.3.1.25 Hemangiomas of the spine: results of surgical management and prognostic variables for local recurrence and mortality in a multicentre study.3.1.26 Chondrosarcomas of the spine: prognostic variables for local recurrence and mortality in a multicentre study.3.1.27 Risk factors for recurrence of surgically treated spine schwannomas: analysis of 169 patients from a multicentre international database.3.2.28 Survival pattern and the effect of surgery on health related quality of life and functional outcome in patients with metastatic epidural spinal cord compression from lung cancer — the AOSpine North America prospective multicentre study.3.2.29 A biomechanical assessment of kyphoplasty as a stand-alone treatment in a human cadaveric burst fracture model.3.2.30 What is safer in incompetent vertebrae with posterior wall defects, kyphoplasty or vertebroplasty: a study in vertebral analogs.3.3.31 Feasibility of recruiting subjects for acute spinal cord injury (SCI) clinical trials in Canada.3.3.32 Prospective analysis of adverse events in elderly patients with traumatic spinal cord injury.3.3.33 Does traction before surgery influence time to neural decompression in patients with spinal cord injury?3.4.34 Current treatment of individuals with traumatic spinal cord injury: Do we need age-specific guidelines?3.4.35 Current surgical practice for traumatic spinal cord injury in Canada.3.4.36 The importance of “time to surgery” for traumatic spinal cord injured patients: results from an ambispective Canadian cohort of 949 patients.3.5.37 Assessment of a novel coil-shaped radiofrequency probe in the porcine spine.3.5.38 The effect of norepinephrine and dopamine on cerebrospinal fluid pressure after acute spinal cord injury.3.5.39 The learning curve of pedicle screw placement: How many screws are enough?4.1.40 Preliminary report from the Ontario Inter-professional Spine Assessment and Education Clinics (ISAEC).4.1.41 A surrogate model of the spinal cord complex for simulating bony impingement.4.1.42 Clinical and surgical predictors of specific complications following surgery for the treatment of degenerative cervical myelopathy: results from the multicentre, prospective AOSpine international study on 479 patients.4.2.43 Outcomes of surgical management of cervical spondylotic myelopathy: results of the prospective, multicentre, AOSpine international study in 479 patients.4.2.44 A clinical prediction rule for clinical outcomes in patients undergoing surgery for degenerative cervical myelopathy: analysis of an international AOSpine prospective multicentre data set of 757 subjects.4.2.45 The prevalence and impact of low back and leg pain among aging Canadians: a cross-sectional survey.4.3.46 Adjacent segment pathology: Progressive disease course or a product of iatrogenic fusion?4.3.47 Natural history of degenerative lumbar spondylolisthesis in patients with spinal stenosis.4.3.48 Changes in self-reported clinical status and health care utilization during wait time for surgical spine consultation: a prospective observational study.4.3.49 The Canadian surgical wait list for lumbar degenerative spinal stenosis has a detrimental effect on patient outcomes.4.3.50 Segmental lordosis is independent of interbody cage position in XLIF.4.3.51 Elevated patient BMI does not negatively affect self-reported outcomes of thoracolumbar surgery.1.5.52 The Spinal Stenosis Pedometer and Nutrition Lifestyle Intervention (SSPANLI): development and pilot.1.5.53 Study evaluating the variability of surgical strategy planning for patients with adult spinal deformity.1.5.54 Atlantoaxial instability in acute odontoid fractures is associated with nonunion and mortality.1.5.55 Peripheral hypersensitivity to subthreshold stimuli persists after resolution of acute experimental disc-herniation neuropathy.1.5.56 Radiation induced lumbar spinal osteonecrosis: case report and literature review.1.5.57 Comparative outcomes and cost-utility following surgical treatment of focal lumbar spinal stenosis compared with osteoarthritis of the hip or knee: Part 2 — estimated lifetime incremental cost-utility ratios.1.5.58 A predictive model of progression for adolescent idiopathic scoliosis based on 3D spine parameters at first visit.1.5.59 Development of a clinical prediction model for surgical decision making in patients with degenerative lumbar spine disease.2.5.60 Canadian spine surgery fellowship education: evaluating opportunity in developing a nationally based training curriculum.2.5.61 Pedicle subtraction osteotomy for severe proximal thoracic junctional kyphosis.2.5.62 A comparison of spine surgery referrals triaged through a multidisciplinary care pathway versus conventional referrals.2.5.63 Results and complications of posterior-based 3 column osteotomies in patients with previously fused spinal deformities.2.5.64 Orthopaedic Surgical AdVerse Event Severity (Ortho-SAVES) system: identifying opportunities for improved patient safety and resource utilization.2.5.65 Spontaneous spinal extra-axial haematomas — surgical experience in Otago and Southland 2011–2013.2.5.66 Obesity and spinal epidural lipomatosis in cauda equina syndrome.2.5.67 Factors affecting restoration of lumbar lordosis in adult degenerative scoliosis patients treated with lateral trans-psoas interbody fusion.3.6.68 Systematic review of complications in spinal surgery: a comparison of retrospective and prospective study design.3.6.69 Postsurgical rehabilitation patients have similar fear avoidance behaviour levels as those in nonoperative care.3.6.70 Outcomes of surgical treatment of adolescent spondyloptosis: a case series.3.6.71 Surgical success in primary versus revision thoracolumbar spine surgery.3.6.72 The effect of smoking on subjective patient outcomes in thoracolumbar surgery.3.6.73 Modelling patient recovery to predict outcomes following elective thoracolumbar surgery for degenerative pathologies.3.6.74 Outcomes from trans-psoas versus open approaches in the treatment of adult degenerative scoliosis.3.6.75 Lumbar spinal stenosis and presurgical assessment: the impact of walking induced strain on a performance-based outcome measure. Can J Surg 2014. [DOI: 10.1503/cjs.005614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Monitoring of Metastatic Breast Cancer Using Circulating Tumour DNA: A Comparison With Circulating Tumour Cells. Ann Oncol 2012. [DOI: 10.1016/s0923-7534(20)32772-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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876 Non-invasive Monitoring of Metastatic Breast Cancer by Circulating Tumour DNA – a Comparison With Circulating Tumour Cells. Eur J Cancer 2012. [DOI: 10.1016/s0959-8049(12)71508-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Canadian Spine Society abstracts1.1.01 Supraspinal modulation of gait abnormalities associated with noncompressive radiculopathy may be mediated by altered neurotransmitter sensitivity1.1.02 Neuroprotective effects of the sodium-glutamate blocker riluzole in the setting of experimental chronic spondylotic myelopathy1.1.03 The effect of timing to decompression in cauda equina syndrome using a rat model1.2.04 Intraoperative waste in spine surgery: incidence, cost and effectiveness of an educational program1.2.05 Looking beyond the clinical box: the health services impact of surgical adverse events1.2.06 Brace versus no brace for the treatment of thoracolumbar burst fractures without neurologic injury: a multicentre prospective randomized controlled trial1.2.07 Adverse event rates in surgically treated spine injuries without neurologic deficit1.2.08 Functional and quality of life outcomes in geriatric patients with type II odontoid fracture: 1-year results from the AOSpine North America Multi-Center Prospective GOF Study1.3.09 National US practices in pediatric spinal fusion: in-hospital complications, length of stay, mortality, costs and BMP utilization1.3.10 Current trends in the surgical treatment of adolescent idiopathic scoliosis in Canada1.3.11 Sagittal spinopelvic parameters help predict the risk of proximal junctional kyphosis for children treated with posterior distraction-based implants1.4.12 Correlations between changes in surface topography and changes in radiograph measurements from before to 6 months after surgery in adolescents with idiopathic scoliosis1.4.13 High upper instrumented vertebra (UIV) sagittal angle is associated with UIV fracture in adult deformity corrections1.4.14 Correction of adult idiopathic scoliosis using intraoperative skeletal traction1.5.01 Cauda equina: using management protocols to reduce delays in diagnosis1.5.02 Predicting the need for tracheostomy in patients with acute traumatic spinal cord injury1.5.03 A novel animal model of cervical spondylotic myelopathy: an opportunity to identify new therapeutic targets1.5.04 A review of preference-based measures of health-related quality of life in spinal cord injury research1.5.05 Predicting postoperative neuropathic pain following surgery involving nerve root manipulation based on intraoperative electromyographic activity1.5.06 Detecting positional injuries in prone spinal surgery1.5.07 Percutaneous thoracolumbar stabilization for trauma: surgical morbidity, clinical outcomes and revision surgery1.5.08 Systemic inflammatory response syndrome in spinal cord injury patients: Does its presence at admission affect patient outcomes?2.1.15 One hundred years of spine surgery — a review of the evolution of our craft and practice in the spine surgical century [presentation]2.1.16 Prevalence of preoperative MRI findings of adjacent segment disc degeneration in patients undergoing anterior cervical discectomy and fusion2.1.17 Adverse event rates of surgically treated cervical spondylopathic myelopathy2.1.18 Morphometricand dynamic changes in the cervical spine following anterior cervical discectomy and fusion and cervical disc arthroplasty2.1.19 Is surgery for cervical spondylotic myelopathy cost-effective? A cost–utility analysis based on data from the AO Spine North American Prospective Multicentre CSM Study2.2.20 Cost–utility of lumbar decompression with or without fusion for patients with symptomatic degenerative lumbar spondylolisthesis (DLS)2.2.21 Minimally invasive surgery lumbar fusion for low-grade isthmic and degenerative spondylolisthesis: 2- to 5-year follow-up2.2.22 Results and complications of posterior-only reduction and fusion for high-grade spondylolisthesis2.3.23 Fusion versus no fusion in patients with central lumbar spinal stenosis and foraminal stenosis undergoing decompression surgery: comparison of outcomes at baseline and follow-up2.3.24 Two-year results of interspinous spacers (DIAM) as an alternative to arthrodesis for lumbar degenerative disorders2.3.25 Treatment of herniated lumbar disc by sequestrectomy or conventional discectomy2.4.26 No sustained benefit of continuous epidural analgesia for minimally invasive lumbar fusion: a randomized double-blinded placebo controlled study2.4.27 Evidence and current practice in the radiologic assessment of lumbar spine fusion2.4.28 Wiltse versus midline approach for decompression and fusion of the lumbar spine2.5.09 The effect of soft tissue restraints following type II odontoid fractures in the elderly — a biomechanical study2.5.10 Development of an international spinal cord injury (SCI) spinal column injury basic data set2.5.11 Evaluation of instrumentation techniques for a unilateral facet perch and fracture using a validated soft tissue injury model2.5.12 Decreasing neurologic consequences in patients with spinal infection: the testing of a novel diagnostic guideline2.5.13 Prospective analysis of adverse events in surgical treatment of degenerative spondylolisthesis2.5.14 Load transfer characteristics between posterior fusion devices and the lumbar spine under anterior shear loading: an in vitro investigation2.5.15 Preoperative predictive clinical and radiographic factors influencing functional outcome after lumbar discectomy2.5.16 A Thoracolumbar Injury Classification and Severity Score (TLICS) of 4: What should we really do?3.1.29 Adverse events in emergent oncologic spine surgery: a prospective analysis3.1.30 En-bloc resection of primary spinal and paraspinal tumours with critical vascular involvement3.1.31 The treatment impact of minocycline on quantitative MRI in acute spinal cord injury3.1.32 Benefit of minocycline in spinal cord injury — results of a double-blind randomized placebo-controlled study3.2.33 Improvement of magnetic resonance imaging correlation with unilateral motor or sensory deficits using diffusion tensor imaging3.2.34 Comparing care delivery for acute traumatic spinal cord injury in 2 Canadian centres: How do the processes of care differ?3.2.35 Improving access to early surgery: a comparison of 2 centres3.3.36 The effects of early surgical decompression on motor recovery after traumatic spinal cord injury: results of a Canadian multicentre study3.3.37 A clinical prediction model for long-term functional outcome after traumatic spinal cord injury based on acute clinical and imaging factors3.3.38 Effect of motor score on adverse events and quality of life in patients with traumatic spinal cord injury3.4.39 The impact of facet dislocation on neurologic recovery after cervical spinal cord injury: an analysis of data on 325 patients from the Surgical Trial in Acute Spinal Cord Injury Study (STASCIS)3.4.40 Toward a more precise understanding of the epidemiology of traumatic spinal cord injury in Canada3.4.41 Access to care (ACT) for traumatic SCI: a survey of acute Canadian spine centres3.4.42 Use of the Spine Adverse Events Severity (SAVES) instrument for traumatic spinal cord injury3.5.17 Does the type of distraction-based growing system for early onset scoliosis affect postoperative sagittal alignment?3.5.18 Comparison of radiation exposure during thoracolumbar fusion using fluoroscopic guidance versus anatomic placement of pedicle screws3.5.19 Skeletal traction for intraoperative reduction in adolescent idiopathic scoliosis3.5.20 Utility of intraoperative cone-beam computed tomography (O-ARM) and stereotactic navigation in acute spinal trauma surgery3.5.21 Use of a central compression rod to reduce thoracic level spinal osteotomies3.5.22 ICD-10 coding accuracy for spinal cord injured patients3.5.23 Feasibility of patient recruitment in acute SCI trials3.5.24 Treatment of adult degenerative scoliosis with DLIF approaches. Can J Surg 2012. [DOI: 10.1503/cjs.012212] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Personal protection equipment for biological hazards: does it affect tracheal intubation performance? Resuscitation 2007; 74:119-26. [PMID: 17353076 PMCID: PMC7115758 DOI: 10.1016/j.resuscitation.2006.11.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2006] [Revised: 11/06/2006] [Accepted: 11/14/2006] [Indexed: 01/18/2023]
Abstract
Purpose Personal protection equipment (PPE) is recommended for use during airway management of patients with highly contagious respiratory tract illness. While its use in chemical hazards and its effect on airway management has been assessed previously, there has been no research assessing whether this equipment affects the ability to perform tracheal intubation. It is the intention of this investigation to answer this question. Methods Eighteen workers at various level of training were asked to wear three different types of PPE while performing four different types of tracheal intubation. The PPE used included the eye shield, face shield and the “Dustmaster™”. The intubation techniques were direct laryngoscopy, intubation through the intubating laryngeal mask (Fastrach™) and flexible bronchoscopy using the eyepiece and an eyepiece with camera attached. We assessed the time to intubate as well as the incidence of oesophageal intubation. A short questionnaire was used to examine participants’ subjective experiences of wearing the various types of PPE. Results There was no significant effect on the time to intubation for any of the methods studied. However, all subjects found that the face shield was uncomfortably hot to wear. Fibreoptic bronchoscopic intubation using the eyepiece was particularly difficult with all of the PPE used due to the distance of the subjects’ eye from the eyepiece. Conclusion Although the use of PPE may not affect the length of time to intubate manikins, certain types of PPE may be uncomfortable to wear and noisy. Further research is needed to investigate whether this could be a problem in the clinical setting or in actual difficult intubations.
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A simplified analysis of the kinetics of effect of muscle relaxants. Eur J Pharmacol 1990. [DOI: 10.1016/0014-2999(90)94760-u] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Abstract
The relation between plasma concentration and the effects of atracurium was studied in seven patients anaesthetised with thiopentone, fentanyl and nitrous oxide-oxygen. The response to train-of-four stimulation at ten-second intervals with tetanic stimuli applied every five minutes were recorded. The first sign of transmission returning after complete blockade was usually the post-tetanic facilitated twitch, which was noted when the mean atracurium concentration was 1.15 mg 1(-1) (SD 0.77). The most sensitive parameter was the train-of-four ratio, which recovered to 0.5 when the concentration was 0.217 mg 1(-1) (SD 0.56), compared with a concentration of 0.271 (SD 0.85) at 50% recovery for twitch height, 0.221 (SD 0.029) for tetanic peak and 0.231 (SD 0.079) for tetanic fade. The value for the train-of-four ratio differed significantly (P less than 0.05) from that for the twitch height, but other differences were not significant. Once recovery commenced, these four parameters recovered at similar rates, with recovery indices (25 to 75% responses) of 14.8 (SD 1.7), 14.0 (SD 1.0), 14.3 (SD 1.8) and 13.7 (SD 2.1) minutes respectively. Post-tetanic facilitation was most marked during severe but incomplete blockade and tetanic stimulation temporarily reversed the atracurium-induced decrease in train-of-four ratio. Clinically, the use of tetanic stimulation did not improve the sensitivity of neuromuscular monitoring, but post-tetanic count may be useful where monitoring of profound relaxation is required.
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Abstract
The combination of the Hill equation, which describes the concentration-effect relation, with the monoexponential function for the terminal decline of plasma concentration, yields a compound time constant, T beta s1/2. This constant is a combination of the terminal elimination half-life (T beta 1/2) and the exponent (s) of the Hill equation and may be used to describe the time course of recovery from neuromuscular block. The constant may be estimated by non-linear curve fitting to f, the effect expressed as fraction of maximal effect, or by linear regression of the logit function of f. The methods were validated using plasma concentration and effect data from seven patients administered atracurium. The two methods utilizing effect data alone yielded values of 4.2 (0.7) min and 4.3 (0.5) min (mean (SEM)), respectively, for T beta s1/2 compared with 4.1 (0.6) min when the constant was calculated using plasma concentration data for T beta 1/2 and curve fitting to the concentration-effect data to determine s. These methods offer an objective measure of the rate of recovery and a means of testing if redistribution or elimination is the primary process in the termination of drug effect.
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Abstract
Atracurium is a mixture of ten isomers. By high-performance liquid chromatography, using acidified methanol as the mobile phase and silica support, it was separated into its three geometrical isomer groups, cis-cis, cis-trans, and trans-trans, which contain three, four, and three isomers, respectively. The clinically available form of atracurium was made up of 58% cis-cis, 36% cis-trans, and 6% trans-trans isomers. In buffered saline, pH 7.4, at 37 degrees C, the half-lives of the three isomer groups were 57.1 +/- 0.9, 59.7 +/- 0.9, and 66.4 +/- 2.7 min, respectively, for the cis-cis, cis-trans, and trans-trans groups. In whole blood, under similar conditions, the three groups showed different behavior. The cis-cis group broke down in a monoexponential manner with a half-life of 23.3 +/- 2.8 min. The cis-trans group showed bi-exponential breakdown with a rapid phase of 2.3 +/- 0.4 min and a slow phase of 22.1 +/- 2.9 min. The trans-trans group decayed rapidly, but, because of the low concentration of this group in the mixture, kinetic parameters could not be obtained. In eight patients, the mean elimination half-life and apparent clearance of the cis-cis group were 20.6 +/- 1.5 min and 5.3 +/- 0.4 ml.kg-1.min-1, respectively. For the cis-trans group, the apparent elimination half-life and clearance were 17.7 +/- 1.8 min and 9.0 +/- 1.0 ml.kg-1.min-1, but these figures require care in interpretation, as this isomer group contains isomers of widely varying rates of decomposition.(ABSTRACT TRUNCATED AT 250 WORDS)
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Abstract
Addition of gabaculine to brain and liver extracts caused great inhibition of GABA-T activity, a much lesser but still significant inhibition of ALA-T activity, and very little inhibition of ASP-T activity. In contrast, intramuscular administration of gabaculine to mice resulted in considerable inhibition of all three enzyme activities in liver, the order of sensitivity being ALA-T greater than GABA-T greater than ASP-T. The effect of the administered gabaculine on the brain enzyme activities was more along the lines seen in the in vitro experiments but, even here, the relative sensitivities of GABA-T and ALA-T to the inhibition were much more similar than might have been predicted from the in vitro experiments.
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Structure-activity studies on the inhibition of gamma-aminobutyric acid uptake in brain slices by compounds related to nipecotic acid. Can J Physiol Pharmacol 1979; 57:581-5. [PMID: 226252 DOI: 10.1139/y79-089] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Various N-methyl derivatives of nipecotic acid and related compounds were tested as inhibitors of gamma-aminobutyric acid (GABA) uptake into mini slices. N-Methylnipecotic acid, N,N-dimethylnipecotic acid, N-methylguvacine, and N-methylnicotinic acid were effective inhibitors. None of them, however, were as potent as nipecotic acid itself. All the effective inhibitors, including nipecotic acid, also inhibited the uptake of L-proline, but to a much lesser extent. Four of the test compounds produced a depressant action on cerebral cortical neurons, but even N-methylisoguvacine, the most potent in this respect, was considerably less active than GABA. None of the test compounds caused any clearly discernible changes in the gross behaviour or appearance of mice in the 1-h period following intramuscular injection. It was concluded that methylation of the N atom of nipecotic acid and its derivatives was unlikely to lead to the development of agents with greater experimental or therapeutic potential than that of nipecotic acid itself, if the action of the agent was dependent on its effects on GABA uptake.
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Alteration of GABA metabolism in mammalian brain by l-alpha-amino-beta-chloropropionic acid hydroxamide and related compounds. Eur J Pharmacol 1979; 55:247-55. [PMID: 456423 DOI: 10.1016/0014-2999(79)90191-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The administration of L-alpha-amino-beta-chloropropionic acid hydroxamide (L-ACPH) to mice brought about an inhibition in GABA-T activity in the brain of the animals, a significant inhibition occurring with dosage levels as low as 0.25 mmol/kg. Minimum levels of GABA-T activity were reached 3 h after administration of the drug. Brain glutamic acid decarboxylase, DOPA decarboxylase and aspartate aminotransferase activities were not altered by the L-ACPH but alanine aminotransferase activity was totally inhibited. Slight changes in structure caused great changes in the potency of the drugs. For example, the elongation of the L-ACPH structure by one carbon, or a change in the configuration of the amino group from L- to D-, caused a significant decrease in GABA inhibition. The chloro and hydroxamide groups were necessary for inhibitory activity. The administration of L-ACPH to mice delayed the onset of drug induced seizures but had a less noticeable effect against maximal electroshock. The addition of L-ACPH to crude extracts from brain, or to preparations of semipurified GABA-T, also inhibited GABA-T activity. Again the development of the inhibition was time-dependent. Possible mechanisms of action with respect to L-ACPH induced inhibition of GABA-T activity are discussed in the light of the data presented.
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Abstract
The administration of L-cycloserine to mice resulted in a dramatic decrease in the activities of 4-aminobutyrate:2-oxoglutarate aminotransferase (GABA-T) and L-alanine:2-oxoglutarate aminotransferase (ALA-T) in both brain and liver. L-Aspartate:2-oxoglutarate aminotransferase was inhibited only slightly, and brain glutamic acid decarboxylase not at all. Liver ALA-T activity returned to near normal levels within 24 h of L-cycloserine administration whereas liver GABA-T and brain ALA-T activities had returned only halfway to normal levels in the same time period. The recovery in the activity of brain GABA-T was even slower. A consequence of the inhibition of brain GABA-T activity was an elevation in the GABA content of the tissue which was maximal 3 h after L-cycloserine administration and which was still noticeable 8 h after the drug treatment. L-Cycloserine was also a potent in vitro inhibitor of brain GABA-T activity. The inhibition was competitive with respect to GABA, the Ki value being 3.1 X 10(-5) M. The prior administration of L-cycloserine to mice significantly delayed the onset of isonicotinic acid hydrazide induced convulsions.
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L-alpha-amino-beta-chloropropionic acid hydroxamide: an inhibitor of GABA-lapha-oxoglutarate aminotrarsferase. Eur J Pharmacol 1976; 38:189-92. [PMID: 954828 DOI: 10.1016/0014-2999(76)90217-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The intramuscular administration of L-alpha-amino-beta-chloropropinonic acid hydroxamide (2 mmol/kg) to mice strongly inhibited the activity of GABA-T, but not GAD, in the brain of the animals. Adminstration of the compound 3 h prior to isonicotinic acid hydrazide treatment significantly delayed the onset of seizures induced by the hydrazide.
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