26 results on '"Turton N"'
Search Results
2. Experimentally Observed Strain Distributions Near Circular Discontinuities of AA6061-T6 Extrusions During Axial Crush
- Author
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Turton, N., Jin, S. Y., Majumder, A., An, H., Vijayan, V., Altenhof, W., and Green, D.
- Published
- 2011
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3. Small sample analysis: reliable results from small volume cord blood segments: R1475
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Horton, R., Gibson, D., Davy, R., Fry, L., Sami, P., Leonforte, C., Turton, N., Marciniak, M., White, D., Gomez, S., Querol, S., and Madrigal, A.
- Published
- 2013
4. Assessment of the Accuracy of C.T. Staging of Bladder Tumours.
- Author
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TURTON, N. and SIMMONS, K. C.
- Abstract
ABSTRACT Although C.T. is useful in staging bladder tumours it is only as accurate as the resolution of the scanner. Non-enlarged, involved lymph nodes cannot be identified, and interpretation can be inaccurate in the presence of poorly defined tissue planes, for example, post surgery, radiotherapy or if the structures are contiguous. However, C.T. is useful in demonstrating enlarged nodes not detected clinically and it remains a useful tool in staging bladder tumours. The C.T. appearances of bladder tumours in forty-nine patients were reviewed and correlated with either cystectomy and postmortem findings, or biopsy and clinical findings. The ability of C.T. to detect spread of tumour through the bladder wall or adjacent or retroperitoneal nodes was assessed retrospectively. Sources of error in original interpretations were identified. [ABSTRACT FROM AUTHOR]
- Published
- 1984
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5. Multiple System Atrophy: Role Of Coenzyme Q10
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Mantle, D, Turton, N, and Hargreaves, IP
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RM - Abstract
Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by a variable combination of autonomic failure, Parkinsonism, and ataxia. There is currently no treatment available to halt or delay progression of this disorder. Biochemically, MSA is characterized by mitochondrial dysfunction, oxidative stress, and inflammation. In the present article we have therefore reviewed the potential role of coenzyme Q10 (CoQ10) in the pathogenesis and treatment of MSA, on the basis of its role in mitochondrial function, and its antioxidant and anti-inflammatory activities, as well as its reported depletion in blood and cerebellar tissue from MSA patients.
6. EXCHANGE OF COBALT 60 WITH BASIC COBALT HALIDES
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Turton, N
- Published
- 1959
7. The Effect of Neuronal CoQ 10 Deficiency and Mitochondrial Dysfunction on a Rotenone-Induced Neuronal Cell Model of Parkinson's Disease.
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Millichap L, Turton N, Damiani E, Marcheggiani F, Orlando P, Silvestri S, Tiano L, and Hargreaves IP
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- Humans, Ataxia, Cell Line, Tumor, Cell Survival drug effects, Electron Transport Complex I metabolism, Mitochondrial Diseases, Muscle Weakness metabolism, Muscle Weakness chemically induced, Muscle Weakness pathology, Parkinson Disease metabolism, Parkinson Disease pathology, Parkinson Disease etiology, Reactive Oxygen Species metabolism, Mitochondria metabolism, Mitochondria drug effects, Neurons metabolism, Neurons drug effects, Neurons pathology, Oxidative Stress drug effects, Rotenone toxicity, Rotenone adverse effects, Ubiquinone analogs & derivatives, Ubiquinone pharmacology, Ubiquinone deficiency
- Abstract
Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder currently affecting the ageing population. Although the aetiology of PD has yet to be fully elucidated, environmental factors such as exposure to the naturally occurring neurotoxin rotenone has been associated with an increased risk of developing PD. Rotenone inhibits mitochondrial respiratory chain (MRC) complex I activity as well as induces dopaminergic neuronal death. The aim of the present study was to investigate the underlying mechanisms of rotenone-induced mitochondrial dysfunction and oxidative stress in an in vitro SH-SY5Y neuronal cell model of PD and to assess the ability of pre-treatment with Coenzyme Q
10 (CoQ10 ) to ameliorate oxidative stress in this model. Spectrophotometric determination of the mitochondrial enzyme activities and fluorescence probe studies of reactive oxygen species (ROS) production was assessed. Significant inhibition of MRC complex I and II-III activities was observed, together with a significant loss of neuronal viability, CoQ10 status, and ATP synthesis. Additionally, significant increases were observed in intracellular and mitochondrial ROS production. Remarkably, CoQ10 supplementation was found to reduce ROS formation. These results have indicated mitochondrial dysfunction and increased oxidative stress in a rotenone-induced neuronal cell model of PD that was ameliorated by CoQ10 supplementation.- Published
- 2024
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8. Prognostic biomarkers for malignant progression of oral epithelial dysplasia: an updated systematic review and meta-analysis.
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Turton N, Payne K, Higginson J, Praveen P, Mehanna H, and Nankivell P
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- Humans, Prognosis, Mouth Mucosa pathology, ErbB Receptors analysis, DNA Methylation, Aneuploidy, Disease Progression, Mouth Neoplasms pathology, Biomarkers, Tumor analysis, Precancerous Conditions pathology
- Abstract
Oral epithelial dysplasia (OED) is a premalignant condition that carries an appreciable risk of malignant progression. The current grading system for severity, as defined by the World Health Organization, is a valuable clinical tool, but further work is required to improve the accuracy of predicting OED malignant progression. This systematic review aimed to assess progress in prognostic biomarker discovery in OED over the past 16 years. The primary objective was to update the latest evidence on prognostic biomarkers that may predict malignant progression of OED, with strict inclusion criteria of studies with a longitudinal design and long-term follow-up data to enhance the robustness and translational clinical potential of the findings. Of 2829 studies identified through the searching of five databases, 20 met our inclusion criteria. These studies investigated a total of 32 biomarkers, 20 of which demonstrated significant potential to predict malignant progression of OED. Meta-analysis demonstrated the significant prognostic value of four biomarkers: podoplanin, EGFR expression, p16 methylation, and DNA aneuploidy. Our review has identified 20 reported biomarkers with prognostic potential to predict malignant progression in OED, but their translation into clinical practice remains elusive. Further research is required, and this should focus on validating the promising biomarkers identified in large cohort studies, with adherence to standardised reporting guidelines., (Copyright © 2024 The British Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.)
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- 2024
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9. Fluorescent characterization of differentiated myotubes using flow cytometry.
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Nolan A, Heaton RA, Adamova P, Cole P, Turton N, Gillham SH, Owens DJ, and Sexton DW
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- Animals, Mice, Cell Line, Myoblasts cytology, Myoblasts metabolism, Mitochondria metabolism, Fluorescent Dyes chemistry, Myosin Heavy Chains metabolism, Myosin Heavy Chains analysis, Cell Survival, Flow Cytometry methods, Muscle Fibers, Skeletal metabolism, Muscle Fibers, Skeletal cytology, Cell Differentiation, Reactive Oxygen Species metabolism
- Abstract
Flow cytometry is routinely used in the assessment of skeletal muscle progenitor cell (myoblast) populations. However, a full gating strategy, inclusive of difficult to interpret forward and side scatter data, which documents cytometric analysis of differentiated myoblasts (myotubes) has not been reported. Beyond changes in size and shape, there are substantial metabolic and protein changes in myotubes allowing for their potential identification within heterogenous cell suspensions. To establish the utility of flow cytometry for determination of myoblasts and myotubes, C2C12 murine cell populations were assessed for cell morphology and metabolic reprogramming. Laser scatter, both forward (FSC; size) and side (SSC; granularity), measured cell morphology, while mitochondrial mass, reactive oxygen species (ROS) generation and DNA content were quantified using the fluorescent probes, MitoTracker green, CM-H
2 DCFDA and Vybrant DyeCycle, respectively. Immunophenotyping for myosin heavy chain (MyHC) was utilized to confirm myotube differentiation. Cellular viability was determined using Annexin V/propidium iodide dual labelling. Fluorescent microscopy was employed to visualize fluorescence and morphology. Myotube and myoblast populations were resolvable through non-intuitive interpretation of laser scatter-based morphology assessment and mitochondrial mass and activity assessment. Myotubes appeared to have similar sizes to the myoblasts based on laser scatter but exhibited greater mitochondrial mass (159%, p < 0.0001), ROS production (303%, p < 0.0001), DNA content (18%, p < 0.001) and expression of MyHC (147%, p < 0.001) compared to myoblasts. Myotube sub-populations contained a larger viable cluster of cells which were unable to be fractionated from myoblast populations and a smaller population cluster which likely contains apoptotic bodies. Imaging of differentiated myoblasts that had transited through the flow cytometer revealed the presence of intact, 'rolled-up' myotubes, which would alter laser scatter properties and potential transit through the laser beam. Our results indicate that myotubes can be analyzed successfully using flow cytometry. Increased mitochondrial mass, ROS and DNA content are key features that correlate with MyHC expression but due to myotubes 'rolling up' during flow cytometric analysis, laser scatter determination of size is not positively correlated; a phenomenon observed with some size determination particles and related to surface properties of said particles. We also note a greater heterogeneity of myotubes compared to myoblasts as evidenced by the 2 distinct sub-populations. We suggest that acoustic focussing may prove effective in identifying myotube sub populations compared to traditional hydrodynamic focussing., (© 2023 The Authors. Cytometry Part A published by Wiley Periodicals LLC on behalf of International Society for Advancement of Cytometry.)- Published
- 2024
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10. Integra ® Dermal Regeneration Template in Complex Scalp Reconstruction.
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Turton N, Aggarwal A, Twohig E, Gallagher J, McVeigh K, Barnard N, and Payne K
- Abstract
Background/Objectives : The need for surgical reconstruction of scalp defects following the excision of cutaneous skin cancers is an increasingly common procedure. Particular challenges arise when considering options for reconstruction of large defects not amenable to local skin flap coverage. The use of skin grafts poses the risk of donor site morbidity. This paper investigates the emerging use of Integra
® , a synthetic acellular dermal regeneration template, as an alternative or adjunct to skin grafting in scalp reconstruction. Methods : The study presents a retrospective analysis of 101 patients who underwent Integra® -based reconstruction of scalp defects. Demographics, procedure details, complications, need for further surgery, and time to healing were evaluated. Results : The overall success rate of the one-stage Integra® -only procedure was 95%, with a minor complication rate of 30.7%. Anticoagulation medication was identified as an independent risk factor for post-operative infection, while previous head and neck radiotherapy and increased defect depth were associated with the requirement for a second-stage skin graft. Conclusions : These findings support the consideration of Integra® as a safe and viable alternative for both partial and full thickness scalp defects in a select cohort of complex highly co-morbid patients, reducing complications and the need for additional procedures.- Published
- 2024
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11. Biosynthesis, Deficiency, and Supplementation of Coenzyme Q.
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Staiano C, García-Corzo L, Mantle D, Turton N, Millichap LE, Brea-Calvo G, and Hargreaves I
- Abstract
Originally identified as a key component of the mitochondrial respiratory chain, Coenzyme Q (CoQ or CoQ
10 for human tissues) has recently been revealed to be essential for many different redox processes, not only in the mitochondria, but elsewhere within other cellular membrane types. Cells rely on endogenous CoQ biosynthesis, and defects in this still-not-completely understood pathway result in primary CoQ deficiencies, a group of conditions biochemically characterised by decreased tissue CoQ levels, which in turn are linked to functional defects. Secondary CoQ deficiencies may result from a wide variety of cellular dysfunctions not directly linked to primary synthesis. In this article, we review the current knowledge on CoQ biosynthesis, the defects leading to diminished CoQ10 levels in human tissues and their associated clinical manifestations.- Published
- 2023
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12. Potential Biomarkers of Mitochondrial Dysfunction Associated with COVID-19 Infection.
- Author
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Turton N, Millichap L, and Hargreaves IP
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- Humans, Post-Acute COVID-19 Syndrome, Mitochondria metabolism, Biomarkers, Mitochondrial Diseases diagnosis, Mitochondrial Diseases metabolism, COVID-19
- Abstract
Mitochondria play crucial roles in modulating immune responses, and viruses can in turn moderate mitochondrial functioning. Therefore, it is not judicious to assume that clinical outcome experienced in patients with COVID-19 or long COVID may be influenced by mitochondrial dysfunction in this infection. Also, patients who are predisposed to mitochondrial respiratory chain (MRC) disorders may be more susceptible to worsened clinical outcome associated with COVID-19 infection and long COVID. MRC disorders and dysfunction require a multidisciplinary approach for their diagnosis of which blood and urinary metabolite analysis may be utilized, including the measurement of lactate, organic acid and amino acid levels. More recently, hormone-like cytokines including fibroblast growth factor-21 (FGF-21) have also been used to assess possible evidence of MRC dysfunction. In view of their association with MRC dysfunction, assessing evidence of oxidative stress parameters including GSH and coenzyme Q10 (CoQ10) status may also provide useful biomarkers for diagnosis of MRC dysfunction. To date, the most reliable biomarker available for assessing MRC dysfunction is the spectrophotometric determination of MRC enzyme activities in skeletal muscle or tissue from the disease-presenting organ. Moreover, the combined use of these biomarkers in a multiplexed targeted metabolic profiling strategy may further improve the diagnostic yield of the individual tests for assessing evidence of mitochondrial dysfunction in patients pre- and post-COVID-19 infection., (© 2023. The Author(s), under exclusive license to Springer Nature Switzerland AG.)
- Published
- 2023
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13. Depletion and Supplementation of Coenzyme Q10 in Secondary Deficiency Disorders.
- Author
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Mantle D, Turton N, and Hargreaves IP
- Subjects
- Humans, Mitochondria genetics, Mitochondria metabolism, Ubiquinone pharmacology, Dietary Supplements, Mitochondrial Diseases drug therapy, Mitochondrial Diseases genetics
- Abstract
Coenzyme Q10 (CoQ10) deficiency is broadly divided into two types, primary and secondary. Primary CoQ10 deficiencies are relatively rare disorders resulting from mutations in genes directly involved in the CoQ10 biosynthetic pathway, and are not a subject of this article. Secondary CoQ10 disorders are relatively common, and may occur for a variety of reasons; these include mutations in genes not directly related to the synthetic pathway, oxidative stress induced reduction of CoQ10, and the effects of pharmacological agents such as statins. CoQ10 is of key importance in cell metabolism; in addition to its role in mitochondrial oxidative phosphorylation, it is a major endogenous antioxidant, and has a role in the metabolism of sulphides, lipids and amino acids. Given its importance in cell metabolism, it is unsurprising that secondary CoQ10 deficiency has been linked with a wide range of disorders. In this article, we have reviewed evidence of secondary CoQ10 deficiency in both common and less common disorders, and highlighted those disorders in which CoQ10 supplementation has been shown to be of significant clinical benefit., Competing Interests: Mantle is medical adviser to Pharma Nord (UK) Ltd. Iain P. Hargreaves is serving as Guest Editor of this journal. We declare that Iain P. Hargreaves had no involvement in the peer review of this article and has no access to information regarding its peer review. Full responsibility for the editorial process for this article was delegated to Graham Pawelec., (© 2022 The Author(s). Published by IMR Press.)
- Published
- 2022
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14. An evaluation of the clinical utility of C-reactive protein and antibiotic use in patients undergoing major head and neck reconstructive surgery with outcome assessment.
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Archer N, Zebic L, Turton N, Higginson J, Idle M, Praveen P, Martin T, Parmar S, and Breik O
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- Anti-Bacterial Agents therapeutic use, Antibiotic Prophylaxis, C-Reactive Protein, Humans, Outcome Assessment, Health Care, Prospective Studies, Surgical Wound Infection prevention & control, Head and Neck Neoplasms surgery, Plastic Surgery Procedures methods
- Abstract
Purpose: This ambispective observational study aims to evaluate the local utility of peri-operative CRP testing and prophylactic antibiotics in relation to post-operative complications in patients who have undergone major head and neck oncological reconstructive surgery., Results: A total of 79 patients were identified for inclusion; CRP testing was undertaken within the first 3 days postoperatively in 78/79 cases. Results demonstrated no benefit of extended prophylactic antibiotic use in reducing post-operative infection. Forty-two post-operative complications arose. In the prospective arm, CRP did not influence the decision to commence antibiotic therapy for any of the surgical site infections. Age, diabetes, smoking, or high body mass index (BMI) did not appear to affect the incidence of postoperative infection (p > 0.05). There is no evidence that more than 24 h of antibiotic prophylaxis is indicated for patients undergoing head and neck reconstructive surgery., Conclusion: Everyone who is involved in peri-operative patient care should be educated regarding the appropriate use of CRP testing, with the implementation of protocols required to standardize CRP testing and prophylactic antibiotic prescription., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
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- 2022
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15. Dramatic Lockdown Fossil Fuel CO 2 Decrease Detected by Citizen Science-Supported Atmospheric Radiocarbon Observations.
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Turnbull JC, Domingues LG, and Turton N
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- Adolescent, Carbon Dioxide analysis, Communicable Disease Control, Fossil Fuels analysis, Humans, Air Pollutants analysis, COVID-19, Citizen Science
- Abstract
COVID-19 lockdowns resulted in dramatic changes to fossil fuel CO
2 emissions around the world, most prominently in the transportation sector. Yet travel restrictions also hampered observational data collection, making it difficult to evaluate emission changes as they occurred. To overcome this, we used a novel citizen science campaign to detect emission changes during lockdown and engage youth in climate science. Citizen scientists collected grass samples from their garden or local park, from which we analyzed the radiocarbon content to infer the recently added atmospheric fossil fuel CO2 mole fraction at each sampling location. The local fossil fuel CO2 mole fractions during lockdown were compared with a "normal" nonlockdown period. Our results from 17 sites in five cities around New Zealand demonstrate dramatic reductions in traffic emissions of 75 ± 3% during the most severe lockdown restriction period. This is consistent with sparse local traffic count information and a much larger decrease in traffic emissions than reported in global aggregate estimates of emission changes. Our results demonstrate that despite nationally consistent rules on travel during lockdown, emission changes varied by location, with inner-city sites typically dominated by bus traffic showing smaller decreases in emissions than elsewhere.- Published
- 2022
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16. The Biochemical Assessment of Mitochondrial Respiratory Chain Disorders.
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Turton N, Cufflin N, Dewsbury M, Fitzpatrick O, Islam R, Watler LL, McPartland C, Whitelaw S, Connor C, Morris C, Fang J, Gartland O, Holt L, and Hargreaves IP
- Subjects
- Electron Transport, Humans, Mitochondrial Membranes metabolism, Pyruvic Acid metabolism, Reproducibility of Results, Mitochondrial Diseases metabolism
- Abstract
Mitochondrial respiratory chain (MRC) disorders are a complex group of diseases whose diagnosis requires a multidisciplinary approach in which the biochemical investigations play an important role. Initial investigations include metabolite analysis in both blood and urine and the measurement of lactate, pyruvate and amino acid levels, as well as urine organic acids. Recently, hormone-like cytokines, such as fibroblast growth factor-21 (FGF-21), have also been used as a means of assessing evidence of MRC dysfunction, although work is still required to confirm their diagnostic utility and reliability. The assessment of evidence of oxidative stress may also be an important parameter to consider in the diagnosis of MRC function in view of its association with mitochondrial dysfunction. At present, due to the lack of reliable biomarkers available for assessing evidence of MRC dysfunction, the spectrophotometric determination of MRC enzyme activities in skeletal muscle or tissue from the disease-presenting organ is considered the 'Gold Standard' biochemical method to provide evidence of MRC dysfunction. The purpose of this review is to outline a number of biochemical methods that may provide diagnostic evidence of MRC dysfunction in patients.
- Published
- 2022
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17. Experience of orbital floor fractures in a UK level one trauma centre: a focus on the surgical approach and lid-related complications.
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Borghol K, Turton N, and Sharp I
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- Conjunctiva surgery, Female, Humans, Male, Postoperative Complications etiology, Retrospective Studies, Trauma Centers, United Kingdom, Ectropion etiology, Ectropion surgery, Entropion complications, Entropion surgery, Maxillary Fractures surgery, Orbital Fractures complications, Orbital Fractures surgery
- Abstract
The two surgical approaches to access orbital fractures are transconjunctival and transcutaneous. The aim of this study was to assess the outcomes of orbital repairs with a focus on lid-related complications and their management. A retrospective analysis was carried out over a five-year period (January 2015 to January 2020) to assess all consecutive orbital repairs in our unit. Data were collected for variables including demographics, fracture pattern, surgical approach, and details of postoperative complications. A total of 111 patients were included in the study, 94 were male (85%), the majority being between 16 and 45 years of age. A total of 46 (41%) had isolated orbital floor fractures, 31 (28%) zygomaticomaxillary complex, and 18 (16%) Le Fort pattern fractures. Eighty per cent (n = 91) received a transconjunctival approach as first choice. In the transconjunctival group, six (6.6%) had entropion and increased scleral show, four (4.4%) had ectropion, and none had canthal malposition. In the transcutaneous group (n = 20) there was a higher rate of ectropion (25%, n = 5), a lower rate of entropion (n = 1, 5%) and higher rate of increased scleral show (n = 2, 10%). Factors associated with a higher rate of complications included complex fractures, use of conjunctival sutures, and increased length of time to surgery. Seventy-two per cent of patients who suffered entropion required further surgical treatment. The most common complication of the transconjunctival approach was entropion, and clinicians should have a low threshold for early surgical management. We feel that this should be part of the consenting process, especially in high-risk cases., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Crown Copyright © 2021. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2022
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18. Lyme Disease: A Role for Coenzyme Q10 Supplementation?
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Mantle D, Turton N, and Hargreaves IP
- Abstract
Lyme disease results from a bacterial infection following a bite from an infected tick. Patients are initially treated with antibiotics; however, in cases where antibiotic treatment is delayed, or when patients do not respond to antibiotic treatment, fatigue may develop alongside problems affecting the nervous system, cardiovascular system, and joints. It is thought that most of the damage to these tissues results from the excessive inflammatory response of the host, involving a self-reinforcing cycle of mitochondrial dysfunction, oxidative stress and inflammation. In this article, we review the potential role of supplementary coenzyme Q10 (CoQ10) in mediating the pathogenic mechanism underlying Lyme disease, on the basis of its role in mitochondrial function, as well as its anti-inflammatory and antioxidant actions.
- Published
- 2022
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19. Septic Arthritis of the Temporomandibular Joint with Intracranial Extension: A Case Report.
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Turton N, McGoldrick DM, Walker K, Martin T, and Praveen P
- Abstract
Septic arthritis of the temporomandibular joint (TMJ) is rare with few cases reported in the literature. We present a case of septic arthritis of the left TMJ in an 18-year-old man who was initially referred as a suspected TMJ dislocation. He had a 3-day history of pain, trismus and malocclusion with left preauricular swelling and became clinically septic with a positive blood culture containing Fusobacterium necrophorum . Computed tomography revealed left TMJ effusion. A later scan showed evidence of a temporal space collection and development of an intracranial extension in the left middle cranial fossa. The patient underwent needle arthrocentesis and drainage, followed by six weeks of antibiotic therapy following advice from neurosurgery and microbiology. Further imaging revealed resolution of the collection. Few cases have been reported of this unusual diagnosis, and this case demonstrates the importance of close multidisciplinary input in forming an accurate diagnosis and managing appropriately., Competing Interests: Conflict of interestThe authors have no competing interest to declare., (© The Association of Oral and Maxillofacial Surgeons of India 2021.)
- Published
- 2022
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20. COVID-19 and the Assessment of Coenzyme Q10.
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Turton N, Heaton RA, and Hargreaves IP
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- Humans, Mitochondrial Diseases, Post-Acute COVID-19 Syndrome, COVID-19 complications, COVID-19 diagnosis, Ubiquinone analogs & derivatives, Ubiquinone chemistry, Ubiquinone metabolism
- Abstract
Coenzyme Q10 (CoQ10) plays an essential electron carrier role in the mitochondrial electron transfer chain (ETC) as well as being a potent antioxidant and influencing inflammatory mediators. In view of these functions, the reason why certain individuals may be more susceptible to the severe disease or long-term complications (long COVID) of COVID-19 infection may be associated with an underlying deficit in cellular CoQ10 status. Thus, our group has outlined an analytical method for the determination of cellular CoQ10 status using HPLC linked UV detection at 275 nm. This method has been utilized in patient tissue samples to investigate evidence of a CoQ10 deficiency and thus may have potential in determining the possible susceptibility of individuals to severe disease associated with COVID-19 infection or to long COVID., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
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21. The Effect of Organophosphate Exposure on Neuronal Cell Coenzyme Q 10 Status.
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Turton N, Heaton RA, Ismail F, Roberts S, Nelder S, Phillips S, and Hargreaves IP
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- Cell Line, Tumor, Cell Survival drug effects, Electron Transport Complex II metabolism, Electron Transport Complex III metabolism, Humans, Mitochondria drug effects, Ubiquinone metabolism, Ubiquinone pharmacology, Chlorpyrifos toxicity, Dichlorvos toxicity, Insecticides toxicity, Methyl Parathion toxicity, Neurons drug effects, Ubiquinone analogs & derivatives
- Abstract
Organophosphate (OP) compounds are widely used as pesticides and herbicides and exposure to these compounds has been associated with both chronic and acute forms of neurological dysfunction including cognitive impairment, neurophysiological problems and cerebral ataxia with evidence of mitochondrial impairment being associated with this toxicity. In view of the potential mitochondrial impairment, the present study aimed to investigate the effect of exposure to commonly used OPs, dichlorvos, methyl-parathion (parathion) and chloropyrifos (CPF) on the cellular level of the mitochondrial electron transport chain (ETC) electron carrier, coenzyme Q
10 (CoQ10 ) in human neuroblastoma SH-SY5Y cells. The effect of a perturbation in CoQ10 status was also evaluated on mitochondrial function and cell viability. A significant decreased (P < 0.0001) in neuronal cell viability was observed following treatment with all three OPs (100 µM), with dichlorvos appearing to be the most toxic to cells and causing an 80% loss of viability. OP treatment also resulted in a significant diminution in cellular CoQ10 status, with levels of this isoprenoid being decreased by 72% (P < 0.0001), 62% (P < 0.0005) and 43% (P < 0.005) of control levels following treatment with dichlorvos, parathion and CPF (50 µM), respectively. OP exposure was also found to affect the activities of the mitochondrial enzymes, citrate synthase (CS) and mitochondrial electron transport chain (ETC) complex II+III. Dichlorvos and CPF (50 µM) treatment significantly decreased CS activity by 38% (P < 0.0001) and 35% (P < 0.0005), respectively compared to control levels in addition to causing a 54% and 57% (P < 0.0001) reduction in complex II+III activity, respectively. Interestingly, although CoQ10 supplementation (5 μM) was able to restore cellular CoQ10 status and CS activity to control levels following OP treatment, complex II+III activity was only restored to control levels in neuronal cells exposed to dichlorvos (50 µM). However, post supplementation with CoQ10 , complex II+III activity significantly increased by 33% (P < 0.0005), 25% (P < 0.005) and 35% (P < 0.0001) in dichlorvos, parathion and CPF (100 µM) treated cells respectively compared to non-CoQ10 supplemented cells. In conclusion, the results of this study have indicated evidence of neuronal cell CoQ10 deficiency with associated mitochondrial dysfunction following OP exposure. Although CoQ10 supplementation was able to ameliorate OP induced deficiencies in CS activity, ETC complex II+III activity appeared partially refractory to this treatment. Accordingly, these results indicate the therapeutic potential of CoQ10 supplementation in the treatment of OP poisoning. However, higher doses may be required to engender therapeutic efficacy.- Published
- 2021
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22. The Effect of Methylmalonic Acid Treatment on Human Neuronal Cell Coenzyme Q 10 Status and Mitochondrial Function.
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Proctor EC, Turton N, Boan EJ, Bennett E, Philips S, Heaton RA, and Hargreaves IP
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- Cell Line, Tumor, Electron Transport drug effects, Humans, Membrane Potential, Mitochondrial drug effects, Ubiquinone metabolism, Methylmalonic Acid pharmacology, Mitochondria drug effects, Mitochondria metabolism, Neurons drug effects, Neurons metabolism, Ubiquinone analogs & derivatives
- Abstract
Methylmalonic acidemia is an inborn metabolic disease of propionate catabolism, biochemically characterized by accumulation of methylmalonic acid (MMA) to millimolar concentrations in tissues and body fluids. However, MMA's role in the pathophysiology of the disorder and its status as a "toxic intermediate" is unclear, despite evidence for its ability to compromise antioxidant defenses and induce mitochondrial dysfunction. Coenzyme Q
10 (CoQ10 ) is a prominent electron carrier in the mitochondrial respiratory chain (MRC) and a lipid-soluble antioxidant which has been reported to be deficient in patient-derived fibroblasts and renal tissue from an animal model of the disease. However, at present, it is uncertain which factors are responsible for inducing this CoQ10 deficiency or the effect of this deficit in CoQ10 status on mitochondrial function. Therefore, in this study, we investigated the potential of MMA, the principal metabolite that accumulates in methylmalonic acidemia, to induce a cellular CoQ10 deficiency. In view of the severe neurological presentation of patients with this condition, human neuroblastoma SH-SY5Y cells were used as a neuronal cell model for this investigation. Following treatment with pathological concentrations of MMA (>0.5 mM), we found a significant ( p = 0.0087) ~75% reduction in neuronal cell CoQ10 status together with a significant ( p = 0.0099) decrease in MRC complex II-III activity at higher concentrations (>2 mM). The deficits in neuronal CoQ10 status and MRC complex II-III activity were associated with a loss of cell viability. However, no significant impairment of mitochondrial membrane potential (ΔΨm) was detectable. These findings indicate the potential of pathological concentrations of MMA to induce a neuronal cell CoQ10 deficiency with an associated loss of MRC complex II-III activity. However, in the absence of an impairment of ΔΨm, the contribution this potential deficit in cellular CoQ10 status makes towards the disease pathophysiology methylmalonic acidemia has yet to be fully elucidated.- Published
- 2020
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23. Mechanisms of Mitochondrial Dysfunction in Lysosomal Storage Disorders: A Review.
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Stepien KM, Roncaroli F, Turton N, Hendriksz CJ, Roberts M, Heaton RA, and Hargreaves I
- Abstract
Mitochondrial dysfunction is emerging as an important contributory factor to the pathophysiology of lysosomal storage disorders (LSDs). The cause of mitochondrial dysfunction in LSDs appears to be multifactorial, although impaired mitophagy and oxidative stress appear to be common inhibitory mechanisms shared amongst these heterogeneous disorders. Once impaired, dysfunctional mitochondria may impact upon the function of the lysosome by the generation of reactive oxygen species as well as depriving the lysosome of ATP which is required by the V-ATPase proton pump to maintain the acidity of the lumen. Given the reported evidence of mitochondrial dysfunction in LSDs together with the important symbiotic relationship between these two organelles, therapeutic strategies targeting both lysosome and mitochondrial dysfunction may be an important consideration in the treatment of LSDs. In this review we examine the putative mechanisms that may be responsible for mitochondrial dysfunction in reported LSDs which will be supplemented with morphological and clinical information.
- Published
- 2020
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24. The Functions of Long Non-Coding RNA during Embryonic Cardiovascular Development and Its Potential for Diagnosis and Treatment of Congenital Heart Disease.
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Turton N, Swan R, Mahenthiralingam T, Pitts D, and Dykes IM
- Abstract
Congenital heart disease (CHD) arises due to errors during the embryonic development of the heart, a highly regulated process involving an interplay between cell-intrinsic transcription factor expression and intercellular signalling mediated by morphogens. Emerging evidence indicates that expression of these protein-coding genes is controlled by a plethora of previously unappreciated non-coding RNAs operating in complex feedback-control circuits. In this review, we consider the contribution of long non-coding RNA (lncRNA) to embryonic cardiovascular development before discussing applications to CHD diagnostics and therapeutics. We discuss the process of lineage restriction during cardiovascular progenitor cell differentiation, as well as the subsequent patterning of the cardiogenic progenitor fields, taking as an example the regulation of NODAL signalling in left-right patterning of the heart. lncRNA are a highly versatile group. Nuclear lncRNA can target specific genomic sequences and recruit chromatin remodelling complexes. Some nuclear lncRNA are transcribed from enhancers and regulate chromatin looping. Cytoplasmic lncRNA act as endogenous competitors for micro RNA, as well as binding and sequestering signalling proteins. We discuss features of lncRNA that limit their study by conventional methodology and suggest solutions to these problems., Competing Interests: The authors declare no conflict of interest.
- Published
- 2019
- Full Text
- View/download PDF
25. Implementation and Challenges of Direct Acoustic Dosing into Cell-Based Assays.
- Author
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Roberts K, Callis R, Ikeda T, Paunovic A, Simpson C, Tang E, Turton N, and Walker G
- Subjects
- Acoustics, Biochemical Phenomena, Biomedical Technology history, Biomedical Technology instrumentation, Cytological Techniques history, Cytological Techniques instrumentation, High-Throughput Screening Assays history, High-Throughput Screening Assays instrumentation, History, 21st Century, Solutions, Biomedical Technology methods, Cytological Techniques methods, High-Throughput Screening Assays methods
- Abstract
Since the adoption of Labcyte Echo Acoustic Droplet Ejection (ADE) technology by AstraZeneca in 2005, ADE has become the preferred method for compound dosing into both biochemical and cell-based assays across AstraZeneca research and development globally. The initial implementation of Echos and the direct dosing workflow provided AstraZeneca with a unique set of challenges. In this article, we outline how direct Echo dosing has evolved over the past decade in AstraZeneca. We describe the practical challenges of applying ADE technology to 96-well, 384-well, and 1536-well assays and how AstraZeneca developed and applied software and robotic solutions to generate fully automated and effective cell-based assay workflows., (© 2015 Society for Laboratory Automation and Screening.)
- Published
- 2016
- Full Text
- View/download PDF
26. Gene expression and amplification in breast carcinoma cells with intrinsic and acquired doxorubicin resistance.
- Author
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Turton NJ, Judah DJ, Riley J, Davies R, Lipson D, Styles JA, Smith AG, and Gant TW
- Subjects
- Breast Neoplasms drug therapy, Carcinoma drug therapy, Drug Resistance genetics, Female, Gene Amplification, Gene Deletion, Gene Expression Profiling, Humans, Phenotype, Receptors, Estrogen analysis, Antineoplastic Agents pharmacology, Breast Neoplasms genetics, Carcinoma genetics, Doxorubicin pharmacology
- Abstract
The multidrug resistance (MDR) phenotype is a major cause of cancer treatment failure. Here the expressions of 4224 genes were analysed for association with intrinsic or acquired doxorubicin (DOX) resistance. A cluster of overexpressed genes related to DOX resistance was observed. Included in this cluster was ABCB1 the P-glycoprotein transporter protein gene and MMP1 (Matrix Metalloproteinase 1), indicative of the invasive nature of resistant cells, and the oxytocin receptor (OXTR), a potential new therapeutic target. Overexpression of genes associated with xenobiotic transformation, cell transformation, cell signalling and lymphocyte activation was also associated with DOX resistance as was estrogen receptor negativity. In all carcinoma cells, compared with HBL100 a putatively normal breast epithelial cell line, a cluster of overexpressed genes was identified which included several keratins, in particular keratins 8 and 18 which are regulated through the ras signalling pathway. Analysis of genomic amplifications and deletions revealed specific genetic alterations common to both intrinsic and acquired DOX resistance including ABCB1, PGY3 (ABCB4) and BAK. The findings shown here indicate new possibilities for the diagnosis of DOX resistance using gene expression, and potential novel therapeutic targets for pharmacological intervention.
- Published
- 2001
- Full Text
- View/download PDF
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