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1.
PLoS One ; 19(5): e0302899, 2024.
Article in English | MEDLINE | ID: mdl-38728282

ABSTRACT

BACKGROUND: Low back pain (LBP) is a major global disability contributor with profound health and socio-economic implications. The predominant form is non-specific LBP (NSLBP), lacking treatable pathology. Active physical interventions tailored to individual needs and capabilities are crucial for its management. However, the intricate nature of NSLBP and complexity of clinical classification systems necessitating extensive clinical training, hinder customised treatment access. Recent advancements in machine learning and computer vision demonstrate promise in characterising NSLBP altered movement patters through wearable sensors and optical motion capture. This study aimed to develop and evaluate a machine learning model (i.e., 'BACK-to-MOVE') for NSLBP classification trained with expert clinical classification, spinal motion data from a standard video alongside patient-reported outcome measures (PROMs). METHODS: Synchronised video and three-dimensional (3D) motion data was collected during forward spinal flexion from 83 NSLBP patients. Two physiotherapists independently classified them as motor control impairment (MCI) or movement impairment (MI), with conflicts resolved by a third expert. The Convolutional Neural Networks (CNNs) architecture, HigherHRNet, was chosen for effective pose estimation from video data. The model was validated against 3D motion data (subset of 62) and trained on the freely available MS-COCO dataset for feature extraction. The Back-to-Move classifier underwent fine-tuning through feed-forward neural networks using labelled examples from the training dataset. Evaluation utilised 5-fold cross-validation to assess accuracy, specificity, sensitivity, and F1 measure. RESULTS: Pose estimation's Mean Square Error of 0.35 degrees against 3D motion data demonstrated strong criterion validity. Back-to-Move proficiently differentiated MI and MCI classes, yielding 93.98% accuracy, 96.49% sensitivity (MI detection), 88.46% specificity (MCI detection), and an F1 measure of .957. Incorporating PROMs curtailed classifier performance (accuracy: 68.67%, sensitivity: 91.23%, specificity: 18.52%, F1: .800). CONCLUSION: This study is the first to demonstrate automated clinical classification of NSLBP using computer vision and machine learning with standard video data, achieving accuracy comparable to expert consensus. Automated classification of NSLBP based on altered movement patters video-recorded during routine clinical examination could expedite personalised NSLBP rehabilitation management, circumventing existing healthcare constraints. This advancement holds significant promise for patients and healthcare services alike.


Subject(s)
Low Back Pain , Machine Learning , Humans , Low Back Pain/therapy , Low Back Pain/diagnosis , Low Back Pain/classification , Low Back Pain/physiopathology , Male , Female , Adult , Middle Aged , Neural Networks, Computer , Movement , Precision Medicine/methods , Patient Reported Outcome Measures
2.
Front Digit Health ; 6: 1307817, 2024.
Article in English | MEDLINE | ID: mdl-38698890

ABSTRACT

Emotions play an important role in human-computer interaction, but there is limited research on affective and emotional virtual agent design in the area of teaching simulations for healthcare provision. The purpose of this work is twofold: firstly, to describe the process for designing affective intelligent agents that are engaged in automated communications such as person to computer conversations, and secondly to test a bespoke prototype digital intervention which implements such agents. The presented study tests two distinct virtual learning environments, one of which was enhanced with affective virtual patients, with nine 3rd year nursing students specialising in mental health, during their professional practice stage. All (100%) of the participants reported that, when using the enhanced scenario, they experienced a more realistic representation of carer/patient interaction; better recognition of the patients' feelings; recognition and assessment of emotions; a better realisation of how feelings can affect patients' emotional state and how they could better empathise with the patients.

3.
Br J Anaesth ; 132(5): 1049-1062, 2024 May.
Article in English | MEDLINE | ID: mdl-38448269

ABSTRACT

BACKGROUND: Artificial intelligence (AI) for ultrasound scanning in regional anaesthesia is a rapidly developing interdisciplinary field. There is a risk that work could be undertaken in parallel by different elements of the community but with a lack of knowledge transfer between disciplines, leading to repetition and diverging methodologies. This scoping review aimed to identify and map the available literature on the accuracy and utility of AI systems for ultrasound scanning in regional anaesthesia. METHODS: A literature search was conducted using Medline, Embase, CINAHL, IEEE Xplore, and ACM Digital Library. Clinical trial registries, a registry of doctoral theses, regulatory authority databases, and websites of learned societies in the field were searched. Online commercial sources were also reviewed. RESULTS: In total, 13,014 sources were identified; 116 were included for full-text review. A marked change in AI techniques was noted in 2016-17, from which point on the predominant technique used was deep learning. Methods of evaluating accuracy are variable, meaning it is impossible to compare the performance of one model with another. Evaluations of utility are more comparable, but predominantly gained from the simulation setting with limited clinical data on efficacy or safety. Study methodology and reporting lack standardisation. CONCLUSIONS: There is a lack of structure to the evaluation of accuracy and utility of AI for ultrasound scanning in regional anaesthesia, which hinders rigorous appraisal and clinical uptake. A framework for consistent evaluation is needed to inform model evaluation, allow comparison between approaches/models, and facilitate appropriate clinical adoption.


Subject(s)
Anesthesia, Conduction , Artificial Intelligence , Humans , Ultrasonography , Computer Simulation , Databases, Factual
4.
J Inherit Metab Dis ; 2023 Dec 04.
Article in English | MEDLINE | ID: mdl-38044746

ABSTRACT

Argininosuccinate lyase (ASL) is integral to the urea cycle detoxifying neurotoxic ammonia and the nitric oxide (NO) biosynthesis cycle. Inherited ASL deficiency causes argininosuccinic aciduria (ASA), a rare disease with hyperammonemia and NO deficiency. Patients present with developmental delay, epilepsy and movement disorder, associated with NO-mediated downregulation of central catecholamine biosynthesis. A neurodegenerative phenotype has been proposed in ASA. To better characterise this neurodegenerative phenotype in ASA, we conducted a retrospective study in six paediatric and adult metabolic centres in the UK in 2022. We identified 60 patients and specifically looked for neurodegeneration-related symptoms: movement disorder such as ataxia, tremor and dystonia, hypotonia/fatigue and abnormal behaviour. We analysed neuroimaging with diffusion tensor imaging (DTI) magnetic resonance imaging (MRI) in an individual with ASA with movement disorders. We assessed conventional and DTI MRI alongside single photon emission computer tomography (SPECT) with dopamine analogue radionuclide 123 I-ioflupane, in Asl-deficient mice treated by hASL mRNA with normalised ureagenesis. Movement disorders in ASA appear in the second and third decades of life, becoming more prevalent with ageing and independent from the age of onset of hyperammonemia. Neuroimaging can show abnormal DTI features affecting both grey and white matter, preferentially basal ganglia. ASA mouse model with normalised ureagenesis did not recapitulate these DTI findings and showed normal 123 I-ioflupane SPECT and cerebral dopamine metabolomics. Altogether these findings support the pathophysiology of a late-onset movement disorder with cell-autonomous functional central catecholamine dysregulation but without or limited neurodegeneration of dopaminergic neurons, making these symptoms amenable to targeted therapy.

5.
J Clin Transl Sci ; 7(1): e115, 2023.
Article in English | MEDLINE | ID: mdl-37250990

ABSTRACT

Patient and public involvement (PPI) must be more frequently embedded within clinical research to ensure translational outcomes are patient-led and meet patient needs. Active partnerships with patients and public groups are an important opportunity to hear patient voices, understand patient needs, and inform future research avenues. A hereditary renal cancer (HRC) PPI group was developed with the efforts of patient participants (n = 9), pooled from recruits within the early detection for HRC pilot study, working in collaboration with researchers and healthcare professionals (n = 8). Patient participants had HRC conditions including Von Hippel-Lindau (n = 3) and Hereditary Leiomyomatosis and Renal Cell Carcinoma (n = 5), and public participants included two patient Trustees (n = 2) from VHL UK & Ireland Charity. Discussions among the enthusiastic participants guided the development of a novel patient information sheet for HRC patients. This communication tool was designed to aid patients when informing family members about their diagnoses and the wider implications for relatives, a gap identified by participants within group discussions. While this partnership was tailored for a specific HRC patient and public group, the process implemented can be employed for other hereditary cancer groups and could be transferable within other healthcare settings.

6.
Epilepsia ; 64(6): 1612-1626, 2023 06.
Article in English | MEDLINE | ID: mdl-36994644

ABSTRACT

OBJECTIVE: Argininosuccinate lyase (ASL) is integral to the urea cycle, which enables nitrogen wasting and biosynthesis of arginine, a precursor of nitric oxide. Inherited ASL deficiency causes argininosuccinic aciduria, the second most common urea cycle defect and an inherited model of systemic nitric oxide deficiency. Patients present with developmental delay, epilepsy, and movement disorder. Here we aim to characterize epilepsy, a common and neurodebilitating comorbidity in argininosuccinic aciduria. METHODS: We conducted a retrospective study in seven tertiary metabolic centers in the UK, Italy, and Canada from 2020 to 2022, to assess the phenotype of epilepsy in argininosuccinic aciduria and correlate it with clinical, biochemical, radiological, and electroencephalographic data. RESULTS: Thirty-seven patients, 1-31 years of age, were included. Twenty-two patients (60%) presented with epilepsy. The median age at epilepsy onset was 24 months. Generalized tonic-clonic and focal seizures were most common in early-onset patients, whereas atypical absences were predominant in late-onset patients. Seventeen patients (77%) required antiseizure medications and six (27%) had pharmacoresistant epilepsy. Patients with epilepsy presented with a severe neurodebilitating disease with higher rates of speech delay (p = .04) and autism spectrum disorders (p = .01) and more frequent arginine supplementation (p = .01) compared to patients without epilepsy. Neonatal seizures were not associated with a higher risk of developing epilepsy. Biomarkers of ureagenesis did not differ between epileptic and non-epileptic patients. Epilepsy onset in early infancy (p = .05) and electroencephalographic background asymmetry (p = .0007) were significant predictors of partially controlled or refractory epilepsy. SIGNIFICANCE: Epilepsy in argininosuccinic aciduria is frequent, polymorphic, and associated with more frequent neurodevelopmental comorbidities. We identified prognostic factors for pharmacoresistance in epilepsy. This study does not support defective ureagenesis as prominent in the pathophysiology of epilepsy but suggests a role of central dopamine deficiency. A role of arginine in epileptogenesis was not supported and warrants further studies to assess the potential arginine neurotoxicity in argininosuccinic aciduria.


Subject(s)
Argininosuccinic Aciduria , Epilepsy , Humans , Argininosuccinic Aciduria/complications , Argininosuccinic Aciduria/genetics , Argininosuccinic Aciduria/metabolism , Retrospective Studies , Nitric Oxide , Arginine/metabolism , Arginine/therapeutic use , Epilepsy/complications , Epilepsy/epidemiology , Epilepsy/drug therapy , Urea , Seizures/drug therapy
7.
IEEE Trans Vis Comput Graph ; 28(12): 4186-4197, 2022 12.
Article in English | MEDLINE | ID: mdl-34033541

ABSTRACT

Using optical sensors to track hand gestures in virtual reality (VR) simulations requires issues such as occlusion, field-of-view, accuracy and stability of sensors to be addressed or mitigated. We introduce an optical hand-based interaction system that comprises two Leap Motion sensors mounted onto a VR headset at different orientations. Our system collects sensor data from the leap motions, combines and processes it to produce optimal hand tracking data, that minimises the effect of sensor occlusion and noise. This contrasts with previous systems that do not use multiple head-mounted sensors or incorporate hand-data aggregation. We also present a study that compares the proposed system with glove-based and traditional motion controller-based interaction. We investigate hand interactions effect on the feeling of naturalness and immersion. The results show that the use of two head-mounted sensors and the data aggregation system increased the number of valid hands presented to the user and can be successfully applied to VR. The user study shows that there is a strong preference for the proposed system due to the natural feeling and freeing interaction. The absence of an indirect interface such as gloves or controllers was found to aid in creating a more natural and immersive experience.


Subject(s)
User-Computer Interface , Virtual Reality , Computer Graphics , Motion , Gestures , Hand
9.
J Emerg Med ; 57(2): 129-139, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31262547

ABSTRACT

BACKGROUND: Long-term outcomes after drowning-related cardiac arrest are not well characterized. OBJECTIVE: Our aims were to estimate long-term survival and identify prognostic factors in a large, population-based cohort of drowning victims with cardiac arrest. METHODS: We conducted a population-based prospective cohort study (1974-1996) of Western Washington Drowning Registry (WWDR) subjects with out-of-hospital cardiac arrest and attempted professional resuscitation. The primary outcome was long-term survival through 2012. We tabulated Utstein-style exposure variables, estimated Kaplan-Meier curves, and identified prognostic factors with Cox proportional hazard modeling. RESULTS: Of 2824 WWDR cases, 407 subjects (median age 17 years [interquartile range 3-33 years], 81% were male) were included. Only 54 (13%) were still alive after 1663 person-years of follow-up. Most deaths occurred after termination of initial resuscitation or during initial hospitalization. Risk of subsequent death after hospital discharge was 9.6 (95% confidence interval [CI] 5.7-15.9) per 1000 person-years. Long-term survival differed by Utstein variables (older age, illicit substance use, pre-drowning activity, submersion duration, cardiopulmonary resuscitation duration, intubation, defibrillation, and medications) and inpatient markers of illness severity (vital signs, Glasgow Coma Scale, laboratory values, shock). In adjusted analyses, older age (hazard ratio [HR] 1.01; 95% CI 1.01-1.02), epinephrine administration (HR 1.92; 95% CI 1.31-2.80), antiepileptic administration (HR 0.53; 95% CI 0.35-0.81), initial arterial pH (HR 0.49; 95% CI 0.26-0.92), and shock (HR 2.19; 95% CI 1.16-4.15) were associated with higher risk of death. CONCLUSIONS: Most cases of drowning-related cardiac arrest were fatal, but survivors to hospital discharge had a low risk of subsequent death that was independently associated with older age and clinical evidence of shock.


Subject(s)
Drowning/physiopathology , Heart Arrest/etiology , Survivors/statistics & numerical data , Adolescent , Adult , Child , Child, Preschool , Cohort Studies , Drowning/epidemiology , Female , Heart Arrest/epidemiology , Heart Arrest/physiopathology , Humans , Kaplan-Meier Estimate , Male , Out-of-Hospital Cardiac Arrest/mortality , Prospective Studies , Registries/statistics & numerical data , Washington/epidemiology
10.
J Sci Med Sport ; 22(5): 516-520, 2019 May.
Article in English | MEDLINE | ID: mdl-30482448

ABSTRACT

OBJECTIVES: To determine the relationship and predictive value of isometric shoulder strength in the development of shoulder pain in young swimmers. DESIGN: Prospective, cohort study. METHODS: Shoulder flexion, extension, external and internal rotation strength tests were performed in elevation on 85 swimmers (14-20 years; 48 females) without current shoulder pain using a hand-held dynamometer. Following testing, swimmers were emailed questionnaires to determine if significant shoulder pain developed within 24 months subsequent to testing. The differences between shoulders that did and did not develop pain and the predictive ability of shoulder strength and strength ratios were investigated using Mann Whitney U tests and receiver operating characteristic curves. RESULTS: Thirty-seven swimmers (47%) returned questionnaires and 18 reported shoulder pain. A comparison of individual shoulders (27 with pain reported and 47 without) determined that shoulder extension strength was lower and flexion:extension strength ratio was higher for male swimmers (n=36 shoulders) who reported shoulder pain compared to those who did not (p=0.04). The predictive value of extension strength was fair (0.72; p=0.03) for males with a cut-off value for extension strength calculated at 13.5% body mass. There were no differences between the two groups in shoulder rotation strength, age, training hours or previous pain history. CONCLUSIONS: Shoulder extension strength, a functional test for swimmers, was associated with and predictive of the development of shoulder pain in male swimmers. Low shoulder extension strength may be a risk factor for the development of shoulder pain in swimmers, proposing a direction for injury prevention and future investigation.


Subject(s)
Muscle Strength , Range of Motion, Articular , Shoulder Pain/diagnosis , Shoulder/physiology , Swimming , Adolescent , Female , Humans , Male , Muscle, Skeletal/physiology , Prospective Studies , Risk Factors , Young Adult
11.
Appl Physiol Nutr Metab ; 43(12): 1314-1320, 2018 Dec.
Article in English | MEDLINE | ID: mdl-29874478

ABSTRACT

Increasing temperature and exercise disrupt tight junctions of the gastrointestinal tract although the contribution of environmental temperature to intestinal damage when exercising is unknown. This study investigated the effect of 2 different environmental temperatures on intestinal damage when exercising at the same relative intensity. Twelve men (mean ± SD; body mass, 81.98 ± 7.95 kg; height, 182.6 ± 7.4 cm) completed randomised cycling trials (45 min, 70% maximal oxygen uptake) in 30 °C/40% relative humidity (RH) and 20 °C/40%RH. A subset of participants (n = 5) also completed a seated passive trial (30 °C/40%RH). Rectal temperature and thermal sensation (TSS) were recorded during each trial and venous blood samples collected at pre- and post-trial for the analysis of intestinal fatty acid-binding protein (I-FABP) level as a marker of intestinal damage. Oxygen uptake was similar between 30 °C and 20 °C exercise trials, as intended (p = 0.94). I-FABP increased after exercise at 30 °C (pre-exercise: 585 ± 188 pg·mL-1; postexercise: 954 ± 411 pg·mL-1) and 20 °C (pre-exercise: 571 ± 175 pg·mL-1; postexercise: 852 ± 317 pg·mL-1) (p < 0.0001) but the magnitude of damage was similar between temperatures (p = 0.58). There was no significant increase in I-FABP concentration following passive heat exposure (p = 0.59). Rectal temperature increased during exercise trials (p < 0.001), but not the passive trial (p = 0.084). TSS increased more when exercising in 30 °C compared with 20 °C (p < 0.001). There was an increase in TSS during the passive heat trial (p = 0.03). Intestinal damage, as measured by I-FABP, following exercise in the heat was similar to when exercising in a cooler environment at the same relative intensity. Passive heat exposure did not increase I-FABP. It is suggested that when exercising in conditions of compensable heat stress, the increase in intestinal damage is predominantly attributable to the exercise component, rather than environmental conditions.


Subject(s)
Exercise/physiology , Heat-Shock Response/physiology , Intestines/physiopathology , Adult , Bicycling/physiology , Body Temperature/physiology , Cross-Over Studies , Fatty Acid-Binding Proteins/blood , Heart Rate/physiology , Hemoglobins , Humans , Male , Temperature , Young Adult
12.
J Am Geriatr Soc ; 63(11): 2375-81, 2015 Nov.
Article in English | MEDLINE | ID: mdl-26503020

ABSTRACT

OBJECTIVES: To develop a reliable and valid dementia knowledge scale to address limitations of existing measures, support knowledge evaluation in diverse populations, and inform educational intervention development. DESIGN: A five-stage, systematic scale development process was employed to construct and assess the psychometric properties of the Dementia Knowledge Assessment Scale (DKAS). SETTING: Data for the study were generated in an online environment and during clinical dementia care placements from Australian (n = 1,321) and international respondents (n = 446). PARTICIPANTS: Volunteers from a dementia-related massive open online course (n = 1,651), medical students on clinical placement in a residential aged care facility (n = 40), and members of the Australian health workforce (n = 76). MEASUREMENTS: Psychometric properties of the DKAS were established using a literature review to assess the veracity of scale items, respondent feedback during pilot testing, a Delphi study with dementia experts, construction and review by an expert panel, evaluation of item difficulty, item-total and interitem correlations. Principal components analysis (PCA) was also performed along with measures of test-retest reliability, internal consistency, construct validity, and concurrent validity. RESULTS: The pilot DKAS was reduced from 40 to 27 items during analysis. PCA identified four distinct and interpretable factors. The revised DKAS displays high levels of test-retest reliability; internal consistency; and preliminary construct, concurrent, and factorial validity. CONCLUSION: The 27-item DKAS is reliable and shows preliminary validity for the assessment of knowledge deficiencies and change in those who provide care and treatment for people with dementia.


Subject(s)
Dementia , Knowledge , Adult , Australia , Female , Humans , Male , Middle Aged , Psychometrics , Reproducibility of Results
13.
Indian J Clin Biochem ; 28(4): 329-35, 2013 Oct.
Article in English | MEDLINE | ID: mdl-24426233

ABSTRACT

Total capsaicins are extracted from 2 mL aliquots of serum or plasma using methyl-isobutyl ketone, evaporation of the extract to dryness and reconstitution with 200 µL of acetonitrile. The HPLC mobile phase is 40:60 water:acetonitrile. The absorbance of the eluent is monitored at 205 nm. Standardisation uses a known mixture of pure capsaicin and dihydrocapsaicin. Accuracies are 98.9 and 100.6 % for capsaicin and dihydrocapsaicin respectively. Inter batch reproducibility for both is 15 %. The limits of detection are 2.6 and 3.8 ng/mL for capsaicin and dihydrocapsaicin respectively. Analyses of sera obtained previously from human subjects who had eaten chilli containing meals showed that in those that absorbed capsaicins (N = 30) then the median, mean and SD of their serum capsaicin were: 13.4, 18.9 and 16.3 ng/mL. The corresponding data for those sera (N = 13) that had measurable levels of dihydrocapsaicin were: 6.9, 7.5 and 3.6 ng/mL. This procedure is suitable for use in prospective studies of the metabolism of orally ingested chilli.

14.
Blood ; 120(23): 4461-9, 2012 Nov 29.
Article in English | MEDLINE | ID: mdl-22936661

ABSTRACT

Menin functions as a critical oncogenic cofactor of mixed lineage leukemia (MLL) fusion proteins in the development of acute leukemias, and inhibition of the menin interaction with MLL fusion proteins represents a very promising strategy to reverse their oncogenic activity. MLL interacts with menin in a bivalent mode involving 2 N-terminal fragments of MLL. In the present study, we reveal the first high-resolution crystal structure of human menin in complex with a small-molecule inhibitor of the menin-MLL interaction, MI-2. The structure shows that the compound binds to the MLL pocket in menin and mimics the key interactions of MLL with menin. Based on the menin-MI-2 structure, we developed MI-2-2, a compound that binds to menin with low nanomolar affinity (K(d) = 22nM) and very effectively disrupts the bivalent protein-protein interaction between menin and MLL. MI-2-2 demonstrated specific and very pronounced activity in MLL leukemia cells, including inhibition of cell proliferation, down-regulation of Hoxa9 expression, and differentiation. Our results provide the rational and essential structural basis to design next generation of inhibitors for effective targeting of the menin-MLL interaction in leukemia and demonstrate a proof of concept that inhibition of complex multivalent protein-protein interactions can be achieved by a small-molecule inhibitor.


Subject(s)
Antineoplastic Agents/therapeutic use , Leukemia/drug therapy , Myeloid-Lymphoid Leukemia Protein/metabolism , Proto-Oncogene Proteins/metabolism , Amino Acid Sequence , Antineoplastic Agents/chemistry , Antineoplastic Agents/metabolism , Apoptosis/drug effects , Binding Sites/genetics , Cell Differentiation/drug effects , Cell Line, Tumor , Cell Proliferation/drug effects , Crystallography, X-Ray , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , HEK293 Cells , Histone-Lysine N-Methyltransferase , Humans , Immunoblotting , Immunoprecipitation , Leukemia/pathology , Models, Molecular , Molecular Sequence Data , Mutation , Myeloid-Lymphoid Leukemia Protein/chemistry , Myeloid-Lymphoid Leukemia Protein/genetics , Protein Binding/drug effects , Protein Structure, Tertiary , Proto-Oncogene Proteins/chemistry , Proto-Oncogene Proteins/genetics
15.
Nat Chem Biol ; 8(3): 277-84, 2012 Jan 29.
Article in English | MEDLINE | ID: mdl-22286128

ABSTRACT

Translocations involving the mixed lineage leukemia (MLL) gene result in human acute leukemias with very poor prognosis. The leukemogenic activity of MLL fusion proteins is critically dependent on their direct interaction with menin, a product of the multiple endocrine neoplasia (MEN1) gene. Here we present what are to our knowledge the first small-molecule inhibitors of the menin-MLL fusion protein interaction that specifically bind menin with nanomolar affinities. These compounds effectively reverse MLL fusion protein-mediated leukemic transformation by downregulating the expression of target genes required for MLL fusion protein oncogenic activity. They also selectively block proliferation and induce both apoptosis and differentiation of leukemia cells harboring MLL translocations. Identification of these compounds provides a new tool for better understanding MLL-mediated leukemogenesis and represents a new approach for studying the role of menin as an oncogenic cofactor of MLL fusion proteins. Our findings also highlight a new therapeutic strategy for aggressive leukemias with MLL rearrangements.


Subject(s)
Antineoplastic Agents/pharmacology , Leukemia/drug therapy , Myeloid-Lymphoid Leukemia Protein/antagonists & inhibitors , Proto-Oncogene Proteins/antagonists & inhibitors , Animals , Antineoplastic Agents/chemistry , Antineoplastic Agents/therapeutic use , Apoptosis/drug effects , Cell Differentiation/drug effects , Cell Proliferation/drug effects , Cells, Cultured , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , HEK293 Cells , Histone-Lysine N-Methyltransferase , Humans , Leukemia/genetics , Leukemia/metabolism , Leukemia/pathology , Mice , Myeloid-Lymphoid Leukemia Protein/genetics , Myeloid-Lymphoid Leukemia Protein/metabolism , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Structure-Activity Relationship
16.
Curr Protoc Hum Genet ; Appendix 2: 2F, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21735375

ABSTRACT

This protocol describes procedures for checking small laboratory hygrometers for accuracy at three relative humidity (rh) levels. The work arose out of the need to provide laboratory assessors with documentary evidence that the hygrometer used to monitor humidity in the vicinity of the laboratory where medical cytogenetics testing slides are prepared and dried in the ambient environment is reproducible and sufficiently accurate. The procedure is based upon the physicochemical principle that when water or certain saturated salt solutions are placed into a sealed environment, the humidity will equilibrate to well defined levels. We choose to check our hygrometers at three points: 95%, 75%, and 33% rh, using distilled water, saturated sodium chloride solution, and saturated magnesium chloride solution, respectively. Our results have demonstrated that the procedure is convenient and of sufficient accuracy to be fit for this annual hygrometer validation purpose. The procedure takes 24 hr per relative humidity point checked.


Subject(s)
Calibration , Cytogenetic Analysis/instrumentation , Cytogenetics/instrumentation , Metaphase , Cytogenetic Analysis/standards , Cytogenetics/methods , Humans , Humidity , Temperature
17.
J Biol Chem ; 285(52): 40690-8, 2010 Dec 24.
Article in English | MEDLINE | ID: mdl-20961854

ABSTRACT

Chromosomal translocations targeting the mixed lineage leukemia (MLL) gene result in MLL fusion proteins that are found in aggressive human acute leukemias. Disruption of MLL by such translocations leads to overexpression of Hox genes, resulting in a blockage of hematopoietic differentiation that ultimately leads to leukemia. Menin, which directly binds MLL, has been identified as an essential oncogenic co-factor required for the leukemogenic activity of MLL fusion proteins. Here, we characterize the molecular basis of the MLL-menin interaction. Using (13)C-detected NMR experiments, we have mapped the residues within the intrinsically unstructured fragment of MLL that are required for binding to menin. Interestingly, we found that MLL interacts with menin with a nanomolar affinity (K(d) ∼ 10 nM) through two motifs, MBM1 and MBM2 (menin binding motifs 1 and 2). These motifs are located within the N-terminal 43-amino acid fragment of MLL, and the MBM1 represents a high affinity binding motif. Using alanine scanning mutagenesis of MBM1, we found that the hydrophobic residues Phe(9), Pro(10), and Pro(13) are most critical for binding. Furthermore, based on exchange-transferred nuclear Overhauser effect measurements, we established that MBM1 binds to menin in an extended conformation. In a series of competition experiments we showed that a peptide corresponding to MBM1 efficiently dissociates the menin-MLL complex. Altogether, our work establishes the molecular basis of the menin interaction with MLL and MLL fusion proteins and provides the necessary foundation for development of small molecule inhibitors targeting this interaction in leukemias with MLL translocations.


Subject(s)
Myeloid-Lymphoid Leukemia Protein/chemistry , Proto-Oncogene Proteins/chemistry , Amino Acid Motifs , Amino Acid Substitution , Histone-Lysine N-Methyltransferase , Humans , Mutagenesis , Myeloid-Lymphoid Leukemia Protein/genetics , Myeloid-Lymphoid Leukemia Protein/metabolism , Nuclear Magnetic Resonance, Biomolecular , Oncogene Proteins, Fusion/chemistry , Oncogene Proteins, Fusion/genetics , Oncogene Proteins, Fusion/metabolism , Protein Structure, Quaternary , Proto-Oncogene Proteins/genetics , Proto-Oncogene Proteins/metabolism , Structure-Activity Relationship
18.
Ann Clin Biochem ; 46(Pt 4): 322-6, 2009 Jul.
Article in English | MEDLINE | ID: mdl-19487410

ABSTRACT

BACKGROUND: Analysis of copper and zinc in serum is commonly performed using atomic absorption spectrometry (AAS); however, these methods are often not readily available in smaller laboratories. Randox colorimetric assays for copper and zinc in serum were evaluated on the Thermo Electron Data Pro analyser against flame AAS methods. METHODS: Copper and zinc were measured in 48 serum samples using the Randox colorimetric copper (CU2340) and zinc (ZN2341) assays on the Data Pro analyser and the results compared with those from a Varian Spectra 880 atomic absorption spectrometer. A smaller set of samples (n = 15) were also analysed colorimetrically for zinc on the Roche Cobas Mira. RESULTS: Linear regression analyses of Bland and Altman plots from the Data Pro - AAS comparison gave the following results for copper: correlation r = 0.6669 (P < 0.01), slope = -0.2499 (P < 0.01), intercept = 3.219 (P < 0.01). For zinc, results were as follows: correlation r = 0.1976, slope = 0.1807, intercept = -1.922. For the smaller set of samples, the Cobas Mira - AAS comparison for zinc gave correlation r = 0.4379, slope = 0.5294, intercept = -4.074. The results indicated significant systematic and fixed bias between the colorimetric copper and the AAS method. CONCLUSION: Performances in comparison to AAS methods indicated the colorimetric methods, as used, are unsuitable for the accurate determination of copper and zinc in human serum.


Subject(s)
Biological Assay/methods , Colorimetry/methods , Copper/blood , Spectrophotometry, Atomic/methods , Zinc/blood , Humans , Linear Models
19.
Invest Ophthalmol Vis Sci ; 44(2): 497-504, 2003 Feb.
Article in English | MEDLINE | ID: mdl-12556374

ABSTRACT

PURPOSE: The second Cambridge Infant Vision Screening Program examined whether screening for accommodative errors by using videorefraction without cycloplegia could effectively serve as a first stage of screening for refractive errors, measured by standard cycloplegic retinoscopy. The screening also included an orthoptic examination for detection of strabismus. METHODS: All infants born in the Cambridge (UK) Health District, over a 2-year period, were invited for screening. Of those 5142 (76%) with mean age 8.1 +/- 0.8 months (SD) attended and received noncycloplegic videorefraction and an orthoptic examination. All those with a focusing error or orthoptic problem, as well as a randomly selected sample of visually normal control subjects, were invited to follow-up a month later for cycloplegic retinoscopy, repeat noncycloplegic videorefraction and orthoptic examination. RESULTS: Of the 5142 screened, 514 had a focusing error or orthoptic problem (positives). Four hundred thirty-nine of these and 284 visually normal control subjects (negatives) attended follow-up. A refractive or orthoptic condition was confirmed in 59.0% of the positive cases, whereas infants in 96.8% of the negative cases were confirmed normal. Adjusting for the proportions of the population represented by those infants seen at follow-up, sensitivity for the screening procedure was calculated at 0.67 and specificity at 0.96. Detailed results are presented in terms of the different conditions detected at screening (far, near, and anisometropic focus and orthoptic error), distribution of greatest axes at screening, and a comparison of initial videorefraction with repeat videorefraction and cycloplegic retinoscopy. CONCLUSIONS: A noncycloplegic screening procedure, simpler to perform than cycloplegic screening, succeeded in detecting a large proportion of infants with significant ametropia, particularly those with significant hyperopia, which is considered to be a strabismogenic and amblyogenic risk factor.


Subject(s)
Refraction, Ocular , Refractive Errors/diagnosis , Strabismus/diagnosis , Accommodation, Ocular , Female , Humans , Infant , Male , Mass Screening , Orthoptics/methods , Refractive Errors/epidemiology , Risk Factors , Sensitivity and Specificity , Strabismus/epidemiology , United Kingdom/epidemiology , Vision Screening/methods
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