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Rashid J, Wu S, Abdelrahman A, McMillan K. Maxillofacial trauma caused by e-scooters: a retrospective review prior to the extension of the UK scheme. Br J Oral Maxillofac Surg 2024; 62:157-163. [PMID: 38238115 DOI: 10.1016/j.bjoms.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 11/12/2023] [Accepted: 11/28/2023] [Indexed: 03/02/2024]
Abstract
The nationwide extension of the electric scooter (e-scooter) scheme, which began in 2020, aimed to alleviate public transport congestion, to reduce pollution and peak-time road traffic. This retrospective study evaluates the range of e-scooter-related maxillofacial trauma before the recent scheme extension and compares the findings with existing literature on this topic. The Queen Elizabeth Hospital Birmingham, United Kingdom (UK) operates as a Level 1 Regional Major Trauma Centre and serves a population of four million. All patient records between September 2021 to September 2022 were analysed to establish the types of e-scooter-related maxillofacial trauma sustained. A Pearson's chi-squared test was used to assess for significant associations between variables recorded. Falls accounted for the majority of injuries (44.3%), and soft tissue lacerations were the most common maxillofacial injury (38%). Statistically significant results were measured in the following variables: gender and intoxication status (p = 0.007), helmet status and injuries sustained in maxillofacial and non-maxillofacial regions (p = 0.043), mechanism of injury and injuries sustained in both the maxillofacial and non-maxillofacial regions (p = 0.045). E-scooters are an emerging concern within the UK. Further studies across the UK are required to assess the frequency of e-scooter-related injuries. Such data may prove useful in determining the government's decision on e-scooter use on UK roads.
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Affiliation(s)
- J Rashid
- Department of Oral & Maxillofacial Surgery, Queen Elizabeth Hospital Birmingham, Birmingham B15 2GW, United Kingdom.
| | - S Wu
- Department of Oral & Maxillofacial Surgery, Queen Elizabeth Hospital Birmingham, Birmingham B15 2GW, United Kingdom.
| | - A Abdelrahman
- Department of Oral & Maxillofacial Surgery, Queen Elizabeth Hospital Birmingham, Birmingham B15 2GW, United Kingdom.
| | - K McMillan
- Department of Oral & Maxillofacial Surgery, Queen Elizabeth Hospital Birmingham, Birmingham B15 2GW, United Kingdom.
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Chao M, Chan Y, Pan D, Holt E, Tan A, McMillan K, Ho H, Pham T, Thomas J, Orio P, Cokelek M, Joon DL, Foroudi F, Bolton D. Can Perirectal Spacing Help Reduce GI Toxicity in Patients Undergoing Post-Prostatectomy Radiotherapy? Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.1155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Holt E, Chan Y, Tan A, Liu M, Ho H, Manohar P, Pan D, Cham C, McMillan K, Joon DL, Pham T, Foroudi F, Cokelek M, Bolton D, Ng M, Guerrieri M, Chao M. The Use of HA as Rectal Spacer in Prostate Cancer Patients Undergoing Hypofractionated RT: An Australian Experience. Int J Radiat Oncol Biol Phys 2022. [DOI: 10.1016/j.ijrobp.2022.07.1173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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4
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Lin Y, Ong W, Tacey M, Bolton D, Tan A, Chan Y, Cham C, Ho H, Guerrieri M, Foroudi F, Joon D, McMillan K, Koufogiannis G, Manohar P, Liu M, Pham T, Chao M. Impact of Hydrogel and Hyaluronic Acid Rectal Spacer on Rectal Dosimetry and Toxicity in Low-Dose-Rate Prostate Brachytherapy: A Multi-Institutional Analysis of Patient Outcomes. Int J Radiat Oncol Biol Phys 2021. [DOI: 10.1016/j.ijrobp.2021.07.907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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5
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Ahmed A, McMillan K. 856 Mortality and Morbidity Meetings in Oral and Maxillofacial Surgery: Hindsight is 20/20. Br J Surg 2021. [DOI: 10.1093/bjs/znab259.620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
Abstract
Aim
Mortality and Morbidity (M&M) meetings form a critical part of clinical governance however they often suffer from hindsight bias and lack objectivity. To combat this, Kahoot surveys were disseminated to senior clinicians prior to M&M meetings. Each case to be discussed is presented as a survey item with the clinical and radiographic information that was available to the performing surgeon pre-operatively and participants are asked to detail their ideal treatment. The aims of this study were to determine if the introduction of Kahoot surveys prior to M&M meetings improves the objectivity of the discussions and reduces the effects of hindsight bias.
Method
A 12-item questionnaire relating to the introduction and utility of Kahoot surveys prior to M&M discussions was distributed to all registrars and consultants within our department.
Result
An 80% response rate was obtained (16/20 responses). Prior to the introduction of Kahoot surveys, 62.6% of surgeons felt case discussions were clouded by the benefit of hindsight. Comparatively, 68.8% indicated the use of pre-M&M surveys reduced the effects of hindsight bias. 56.3% of participants expressed the objectivity of case discussions improved and 50% felt the quality of feedback improved.
Conclusions
The use of Kahoot surveys prior to M&M meetings demonstrates that withholding the case outcome until each clinician has given their own opinion reduces the effect of hindsight bias. The surveys utilise the Bolam Test, thereby enabling us to determine the correct error classifications with greater objectivity. Furthermore, they facilitate a higher quality of discussion and feedback.
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Affiliation(s)
- A Ahmed
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - K McMillan
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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Farooq S, Sarai R, McMillan K. 1588 A Rare Case of Arteriovenous Malformation Following TMJ Arthroscopy: A Case Report and Review of The Literature. Br J Surg 2021. [DOI: 10.1093/bjs/znab259.393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Patients undergo temporo-mandibular joint (TMJ) arthroscopy as part of the diagnosis and management of chronic pain in the TMJ. Known complications of the procedure include bleeding within the joint spaces, lacerations of the external auditory canal and local nerve damage. We present the case of a 25-year-old woman who developed an arteriovenous fistula in the right pre-auricular region secondary to TMJ arthroscopic examination. She had presented with ongoing TMJ pain necessitating further investigation with arthroscopy. Following her procedure her TMJ symptoms improved, however she developed right pre-auricular swelling of gradual onset, right-sided headaches, and pulsatile tinnitus. Due to her pregnancy of around 16 weeks this was originally linked to expansion in plasma volume and hyperdynamic circulation; however, this was later diagnosed as an extremely rare, post-operative complication of TMJ arthroscopy. Her examination revealed a pre-auricular pulsatile swelling measuring approximately 1.5 cm. Blood tests including ESR and CRP were within normal limits excluding temporal arteritis. An ultrasound scan revealed an AV fistula of the right superficial temporal artery; Her MRI confirmed single vessel supply. Following discussion in the vascular anomalies MDT, she underwent embolisation with PHIL and surgical excision via a preauricular approach. The procedure was successful, and the patient made a full recovery. The literature reports very few cases of iatrogenic arterio-venous fistulas resulting from TMJ arthroscopic surgery. Our case emphasises the importance of a multidisciplinary approach in combining embolisation with surgical excision resulting in the successful management of a rare post-operative complication.
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Affiliation(s)
- S Farooq
- Queen Elizabeth Hospital, Birmingham, United Kingdom
| | - R Sarai
- Queen Elizabeth Hospital, Birmingham, United Kingdom
| | - K McMillan
- Queen Elizabeth Hospital, Birmingham, United Kingdom
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McMillan D, McMillan K, Ettinger K, Arce K. The Influence of Dental Rehabilitation on the Detection and Rate of Cancer Recurrence after Oral Cavity Malignant Tumor Ablation. J Oral Maxillofac Surg 2021. [DOI: 10.1016/j.joms.2021.08.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Dattani A, Aslam A, McMillan K. 125 The Fate of The Third Molar in The Line of a Mandibular Angle Fracture: A Retrospective Study at A Tertiary Centre. Br J Surg 2021. [DOI: 10.1093/bjs/znab134.533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Abstract
Aim: To evaluate the risk of complications associated with retaining or extracting an asymptomatic third molar in the line of an angle fracture. Aiming to seek a consensus whether third molars should be extracted or retained during surgical repair of mandibular angle fractures.
Method
A retrospective study was undertaken at the Queen Elizabeth Hospital, Birmingham. 150 patients across a span of three years underwent open reduction and internal fixation of mandibular angle fractures with third molar involvement. Patients were classified into two groups, tooth retention during angle fracture and tooth removal during angle fracture repair. Hospital records were evaluated to seek the rate of post-operative complications at follow-up
Results
162 angle fractures were identified with ipsilateral wisdom teeth present. In 37 cases the wisdom tooth was removed during surgery. 6 complications (16.2%) occurred in this group necessitating a return to theatre. In 125 cases the wisdom tooth was left in-situ. Complications necessitating a return to theatre occurred in 14 cases (11.1%).
Conclusions
This study indicates that retention of wisdom tooth overall did not significantly increase the risk of complications associated with angle fractures (p = 0.42). Where wisdom tooth pathology was noted its retention was associated with complications requiring a return to theatre (X2=4.40, p = 0.036).
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Affiliation(s)
- A Dattani
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - A Aslam
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
| | - K McMillan
- University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
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Ho H, Ng M, Guerrieri M, Tan A, Bolton D, Chan Y, Lawrentschuk N, Cham C, McMillan K, Sengupta S, Koufogiannis G, Cokelek M, Spencer S, Liu M, Pham T, Lim Joon D, Foroudi F, Tacey M, Khor R, Ding W, Subramanian B, Chao M. Low Dose Rate Brachytherapy and Long-Term Treatment Outcomes In Patients Less Than 60 Years of Age. Int J Radiat Oncol Biol Phys 2020. [DOI: 10.1016/j.ijrobp.2020.07.528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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10
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Higginson J, McMillan K, Mustafa E, Grew N. Use of the superficial inferior epigastric vein as an unusual interpositional vein graft. Br J Oral Maxillofac Surg 2018; 56:761-762. [DOI: 10.1016/j.bjoms.2018.07.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 07/01/2018] [Indexed: 10/28/2022]
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11
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Dover M, McMillan K, Evans M, White N, Rodrigues D, Sharp M, Nishikawa H. Posterior calvarial distraction — a 10-year review of clinical practice and outcomes. Int J Oral Maxillofac Surg 2017. [DOI: 10.1016/j.ijom.2017.02.054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Hardy A, Bostani M, McMillan K, Zankl M, Cagnon C, McNitt-Gray M. TU-H-207A-08: Estimating Radiation Dose From Low-Dose Lung Cancer Screening CT Exams Using Tube Current Modulation. Med Phys 2016. [DOI: 10.1118/1.4957644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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13
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McMillan K, Huang A, Leng S, McCollough C. TH-AB-207A-08: Variation of Size-Specific Dose Estimates Across Patient Sizes Under the Conditions of Automatic Exposure Control. Med Phys 2016. [DOI: 10.1118/1.4958084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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14
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Favazza C, Ferrero A, McMillan K, Bruesewitz M, Yu L, Leng S, Kofler J, McCollough C. SU-G-206-10: Low-Contrast Detectability Vs. Dose for CT Images Reconstructed Using Filtered Backprojection and Iterative Reconstruction: Assessment with a Model Observer. Med Phys 2016. [DOI: 10.1118/1.4956951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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15
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Fujii K, McMillan K, Bostani M, Cagnon C, McNitt-Gray M. SU-E-I-31: Differences Observed in Radiation Doses Across 2 Similar CT Scanners From Adult Brain-Neck CT Angiography. Med Phys 2015. [DOI: 10.1118/1.4924028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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16
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McMillan K, Bostani M, McCollough C, McNitt-Gray M. TU-EF-204-01: Accurate Prediction of CT Tube Current Modulation: Estimating Tube Current Modulation Schemes for Voxelized Patient Models Used in Monte Carlo Simulations. Med Phys 2015. [DOI: 10.1118/1.4925687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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17
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McMillan K, Bostani M, Angel E, McNitt-Gray M. TH-EF-BRA-03: Size-Specific, Scanner-Independent Fetal Dose Estimates in Abdominal and Pelvic CT Examinations of Pregnant Patients. Med Phys 2015. [DOI: 10.1118/1.4926310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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18
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Fujii K, McMillan K, Bostani M, Cagnon C, McNitt-Gray M. TH-EF-BRA-01: Patient-Size Specific Analysis of CT Doses From Lung Cancer Screening. Med Phys 2015. [DOI: 10.1118/1.4926308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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19
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Dunphy L, O’Connell S, McMillan K, Monaghan. A. Management of Low Flow Vascular Malformations of the head and neck: the Birmingham experience. Br J Oral Maxillofac Surg 2014. [DOI: 10.1016/j.bjoms.2014.07.077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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McMillan K, Bostani M, Zankl M, DeMarco J, Cagnon C, McNitt-Gray M. MO-E-17A-08: Attenuation-Based Size Adjusted, Scanner-Independent Organ Dose Estimates for Head CT Exams: TG 204 for Head CT. Med Phys 2014. [DOI: 10.1118/1.4889159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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21
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McMillan K, Bostani M, McCollough C, McNitt-Gray M. MO-E-17A-01: BEST IN PHYSICS (IMAGING) - Calculating SSDE From CT Exams Using Size Data Available in the DICOM Header of CT Localizer Radiographs. Med Phys 2014. [DOI: 10.1118/1.4889153] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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22
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Idle M, Hamilton M, Hammond D, McMillan K, Monaghan A, Williams R. A 10-year prospective analysis of paediatric maxillofacial trauma in Birmingham, UK. Int J Oral Maxillofac Surg 2013. [DOI: 10.1016/j.ijom.2013.07.190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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McMillan K, Khatonabadi M, McNitt-Gray M. SU-E-I-47: A Classification of Validation Tasks for Monte Carlo Simulations of CT Scanners: From Simple to Complex Source Models and Geometries. Med Phys 2013. [DOI: 10.1118/1.4814157] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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24
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Khatonabadi M, Mueller J, McMillan K, Flores C, Cody D, Cagnon C, DeMarco J, McNitt-Gray M. TU-G-103-04: The Accuracy of Monte Carlo Based Dose Estimates Compared to In-Vivo Dose Measurements. Med Phys 2013. [DOI: 10.1118/1.4815473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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25
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McMillan K, DeMarco J, Tenn S, Chow P, McNitt-Gray M, Ruan D. TU-G-103-07: Quantifying the Dose Distribution of OBI CBCT Using Monte Carlo Simulations with a Measurement-Based Source Model. Med Phys 2013. [DOI: 10.1118/1.4815476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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McMillan K, Michailian A, McNitt-Gray M, Ruan D. TH-C-BRA-06: Measurement Based Source Model for On-Board Imager Monte Carlo Dosimetry Simulations. Med Phys 2012. [DOI: 10.1118/1.4736322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Newell J, McMillan K, Grant S, McCabe G. Using functional data analysis to summarise and interpret lactate curves. Comput Biol Med 2006; 36:262-75. [PMID: 16446160 DOI: 10.1016/j.compbiomed.2004.11.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2004] [Accepted: 11/29/2004] [Indexed: 10/25/2022]
Abstract
John Tukey used the term exploratory data analysis (EDA) to describe a philosophy for analyzing data where graphical and numerical summaries are used to uncover interesting structures. The applied statistician today has a much more sophisticated set of methods to use when applying the EDA philosophy. One such collection of methods is functional data analysis (FDA), which was used to explore the structure of lactate curves. A principal components analysis and plots of the second derivatives provide new intuitive endurance markers which correlates highly with other numerical summaries of lactate curves that have been suggested in the literature.
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Affiliation(s)
- J Newell
- Department of Mathematics, National University of Ireland, Galway, Galway, Ireland.
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Abstract
BACKGROUND Improved oxygen uptake improves soccer performance as regards distance covered, involvements with the ball, and number of sprints. Large improvements in oxygen uptake have been shown using interval running. A similar physiological load arising from interval running could be obtained using the soccer ball in training. OBJECTIVES The main aim was to study physiological adaptations to a 10 week high intensity aerobic interval training program performed by professional youth soccer players, using a soccer specific ball dribbling track. METHODS Eleven youth soccer players with a mean (SD) age of 16.9 (0.4) years performed high intensity aerobic interval training sessions twice per week for 10 weeks in addition to normal soccer training. The specific aerobic training consisted of four sets of 4 min work periods dribbling a soccer ball around a specially designed track at 90-95% of maximal heart frequency, with a 3 min recovery jog at 70% of maximal heart frequency between intervals. RESULTS Mean VO2max improved significantly from 63.4 (5.6) to 69.8 (6.6) ml kg(-1) min(-1), or 183.3 (13.2) to 201.5 (16.2) ml kg(-0.75) min(-1) (p<0.001). Squat jump and counter movement jump height increased significantly from 37.7 (6.2) to 40.3 (6.1) cm and 52.0 (4.0) to 53.4 (4.2) cm, respectively (p<0.05). No significant changes in body mass, running economy, rate of force development, or 10 m sprint times occurred. CONCLUSION Performing high intensity 4 min intervals dribbling a soccer ball around a specially designed track together with regular soccer training is effective for improving the VO2max of soccer players, with no negative interference effects on strength, jumping ability, and sprinting performance.
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Affiliation(s)
- K McMillan
- Glasgow Celtic Football Club, Medical Department, 95 Kerrydale Street, Glasgow G40 3RE, UK.
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Grant S, McMillan K, Newell J, Wood L, Keatley S, Simpson D, Leslie K, Fairlie-Clark S. Reproducibility of the blood lactate threshold, 4 mmol.l(-1) marker, heart rate and ratings of perceived exertion during incremental treadmill exercise in humans. Eur J Appl Physiol 2002; 87:159-66. [PMID: 12070627 DOI: 10.1007/s00421-002-0608-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/15/2002] [Indexed: 10/27/2022]
Abstract
The aim of this study was to investigate the reproducibility of blood lactate measurements, heart rate (HR) and ratings of perceived exertion (RPE) during treadmill exercise at speeds corresponding to the lactate threshold ( v(Th,la)-) and a fixed blood lactate concentration of 4 mmol.l(-1)( v(la)-(,4)). Possible differences in reproducibility related to fitness levels were also investigated. A group of 20 men [mean (SD)] [age 20.5 (1.4) years] and 16 women [age 21.2 (0.9) years] took part in the study. The subjects performed two identical incremental exercise tests consisting of at least six 4 min stages. Blood lactate concentrations, HR and RPE were recorded at the end of each stage. Limits of agreement (LoA), correlation coefficients and 95% confidence intervals for the mean difference between tests were employed to investigate the level of agreement and reproducibility of blood lactate concentration, HR and RPE. For the group as a whole, the sample correlation coefficient for speed at v(Th,la)- was r=0.88, and was r=0.92 for the speed at v(la)-(,4). At v(Th,la) -, the correlation coefficients for the moderately fit and unfit were r=0.94 and r=0.36, respectively, and at v(la)-(,4) r=0.93 and r=0.68, respectively. The LoA for the moderately fit group indicated that a change of 1.62 km.h(-1) in v(Th,la)- would be necessary to be considered a change in training status. For HR and RPE, relationships between the tests were generally poor. The LoA suggested that changes in scores must be unacceptably large. These findings cast doubt on the sensitivity of testing for change of blood lactate concentration, HR and RPE in this population.
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Affiliation(s)
- S Grant
- Institute of Biomedical and Life Sciences, University of Glasgow, 64 Oakfield Avenue, G12 8LT, UK. S.
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Tossell JA, Moore JH, McMillan K, Coplan MA. Oxygen 2p.pi., silicon 3p, and carbon 2p interaction in the highest energy occupied molecular orbitals of methylated siloxanes. J Am Chem Soc 2002. [DOI: 10.1021/ja00003a044] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Tossell JA, Moore JH, McMillan K, Subramaniam CK, Coplan MA. The electron momentum density in the highest energy occupied molecular orbital of borazine, B3N3H6: evidence for localization. J Am Chem Soc 2002. [DOI: 10.1021/ja00029a064] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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32
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Crespi F, Campagnola M, Neudeck A, McMillan K, Rossetti Z, Pastorino A, Garbin U, Fratta-Pasini A, Reggiani A, Gaviraghi G, Cominacini L. Can voltammetry measure nitrogen monoxide (NO) and/or nitrites? J Neurosci Methods 2001; 109:59-70. [PMID: 11489301 DOI: 10.1016/s0165-0270(01)00402-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Recently, voltammetry with carbon fibre electrodes (CFE) has been implemented for real time measurement of nitrogen monoxide (NO) indicating that it is oxidised at the potential value of nitrites, approximately +700 mV. In contrast, here we show that modified CFE can monitor NO at oxidation potentials different than that of nitrites, i.e. +550 mV. Indeed, at +550 mV a significant increase of amperometric current levels was obtained when NO but not nitrites, were added to a phosphate buffer saline solution (PBS). Differential pulse voltammetry (DPV) supports these findings as two oxidation peaks were obtained when examining air preserved NO; peak 1 at +550 mV and peak 2 at +700 mV, respectively. In contrast, only peak 2 was monitored when nitrites or a solution of NO oxidised in air was added to PBS. Biological support to these in vitro data comes from the observation that the relaxation of an adrenaline-contracted aortic ring produced via addition of NO is concomitant with peak 1 at +550 mV. The relaxation is almost completed before the appearance of peak 2 at +700 mV. Furthermore, in vivo experiments performed in the striatum of rats show that the amperometric signal monitored at +550 mV is responsive to glutamatergic stimulation or inhibition of NO synthase.
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Affiliation(s)
- F Crespi
- Department of Biology, GlaxoWellcome S.p.A., Medicine Research Centre, via A. Fleming 4, 37135, Verona, Italy.
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Abstract
OBJECTIVES Microvascular targeting with the 585- nm pulsed dye laser (PDL) may provide a new form of therapy to control symptoms caused by recurrent respiratory papillomatosis (RRP). METHODS Ten patients with RRP underwent 13 procedures under general anesthesia with the 585-nm PDL. A micromanipulator (11 procedures) and a flexible nasolaryngoscope (2 procedures) were used to deliver the laser pulses. Patients were followed postoperatively according to protocol. RESULTS Clinical examination revealed regression of papillomas in all patients. Seven patients had complete regression after PDL surgery, and 2 patients had partial response to treatment. One patient was lost to follow-up. No complications were present during this prospective nonrandomized pilot study. CONCLUSION Patients treated with PDL experienced regression of their papillomas. PDL may provide patients with RRP with an alternative treatment without the risks associated with CO(2) laser surgery. This procedure also has potential to be delivered on an outpatient basis with flexible fiberoptic laryngoscopes.
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Affiliation(s)
- T A Valdez
- Department of Otolaryngology--Head and Neck Surgery, Tufts University School of Medicine, New England Medical Center, Boston, MA 02111, USA.
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Abstract
Escape extinction combined with differential reinforcement for acceptance has been demonstrated to be an effective treatment for food selectivity when implemented by trained professionals in clinic settings. This study evaluated the efficacy of parent-implemented escape extinction in the child's natural environment using video monitoring to train parents and assess intervention efficacy. Parents were able to use intervention to significantly increase bites accepted and decrease problem behavior.
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Affiliation(s)
- C M Anderson
- Department of Psychology, West Virginia University, Morgantown 26506, USA
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Stubbs JB, Strickland AD, Frank RK, Simón J, McMillan K, Williams JA. Biodistribution and dosimetry of an aqueous solution containing sodium 3-(125I)iodo-4-hydroxybenzenesulfonate (Iotrex) for brachytherapy of resected malignant brain tumors. Cancer Biother Radiopharm 2000; 15:645-56. [PMID: 11190496 DOI: 10.1089/cbr.2000.15.645] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
UNLABELLED Iotrex is an aqueous radiotherapy solution containing sodium 3-(125I)iodo-4-hydroxybenzenesulfonate (125I-HBS), which is used as the radiation source for the brachytherapy of resected of brain tumor cavity margins with the GliaSite catheter. During routine clinical use of this brachytherapy applicator and radiation source, approximately 0.1% of the afterloaded Iotrex will diffuse through the GliaSite balloon. Our purpose was to assess the radiation doses to normal organs under routine clinical use of the GliaSite. METHODS Five groups of rats received intracerebral injections of an 131I-HBS solution (131I used as a surrogate for 125I in the synthesis of 125I-HBS) with one group sacrificed at 15 minutes, 30 minutes, 1 hour, 2 hours and 4 hours post-administration. Urine was collected and activity retention in numerous organs was measured. The biodistribution data were used to estimate radiation doses to normal organs of the Reference Adult Male and Female phantoms. RESULTS Radioactivity was rapidly and completely cleared from the brain (98% cleared by 2 hours) and total body (urinary clearance; 93%@2 hours). No organ retained > 0.7% of the radioactivity at 4 hours. For 100% loss of the radiotherapy solution from the balloon catheter (device failure), all organs would receive less than 100 mGy (10 rad), except the bladder wall (2800 mGy, 280 rad), uterus (130 mGy, 13 rad) and distal colon (270 mGy, 27 rad). Under normal conditions, all organ doses are 1000-fold lower (< 3 mGy or 0.3 rad). CONCLUSIONS Under routine clinical conditions, the radiation doses to normal organs are inconsequential. Should the maximum clinical load of Iotrex (16.7 GBq of 125I) be released intracerebrally, the radiation doses to all organs would be below the thresholds for deterministic effects.
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Affiliation(s)
- J B Stubbs
- Proxima Therapeutics, Inc., 2555 Marconi Drive, Suite 220, Alpharetta, GA 30005, USA.
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36
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Spurway NC, Watson H, McMillan K, Connolly G. The effect of strength training on the apparent inhibition of eccentric force production in voluntarily activated human quadriceps. Eur J Appl Physiol 2000; 82:374-80. [PMID: 10985590 DOI: 10.1007/s004210000221] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Ten male and ten female young adults trained the knee extensors of one leg eccentrically and those of the other concentrically for 6 weeks, using a gymnasium leg-extension machine. Before and after training, both legs of each subject were tested isometrically for maximum voluntary knee-extensor force, and in both eccentric and concentric isokinetic modes at 30-250 degrees x s(-1) All limbs showed improvements in mean eccentric force (ranging from 18% in the concentrically trained legs of the females to 31% in the eccentrically trained legs of the males, P < 0.01-0.001). Upward trends in isometric and concentric forces were smaller and less- or nonsignificant. In three of the four groups, mean eccentric forces after training were significantly greater than mean isometric forces, a difference that was not evident before training. Ten further subjects of each gender, not trained but tested isometrically and isokinetically three times in 2 weeks, showed no significant improvement over the series of tests. The explanation suggested is that the increased percentage activation ("decreased inhibition"), often regarded as the main mechanism of strength gain in the early weeks of training, had been displayed particularly in the subjects' eccentric performance. This implies that the activation-shortfall, which is reduced by the initial phase of strength training, is largely or completely the same as that responsible for the fact that untrained, voluntary eccentric force is less than that of isolated muscle.
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Affiliation(s)
- N C Spurway
- Centre for Exercise Science and Medicine, Institute of Biomedical and Life Sciences, University of Glasgow, UK.
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37
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McMillan K, Adler M, Auld DS, Baldwin JJ, Blasko E, Browne LJ, Chelsky D, Davey D, Dolle RE, Eagen KA, Erickson S, Feldman RI, Glaser CB, Mallari C, Morrissey MM, Ohlmeyer MH, Pan G, Parkinson JF, Phillips GB, Polokoff MA, Sigal NH, Vergona R, Whitlow M, Young TA, Devlin JJ. Allosteric inhibitors of inducible nitric oxide synthase dimerization discovered via combinatorial chemistry. Proc Natl Acad Sci U S A 2000; 97:1506-11. [PMID: 10677491 PMCID: PMC26464 DOI: 10.1073/pnas.97.4.1506] [Citation(s) in RCA: 168] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Potent and selective inhibitors of inducible nitric oxide synthase (iNOS) (EC ) were identified in an encoded combinatorial chemical library that blocked human iNOS dimerization, and thereby NO production. In a cell-based iNOS assay (A-172 astrocytoma cells) the inhibitors had low-nanomolar IC(50) values and thus were >1,000-fold more potent than the substrate-based direct iNOS inhibitors 1400W and N-methyl-l-arginine. Biochemical studies confirmed that inhibitors caused accumulation of iNOS monomers in mouse macrophage RAW 264.7 cells. High affinity (K(d) approximately 3 nM) of inhibitors for isolated iNOS monomers was confirmed by using a radioligand binding assay. Inhibitors were >1,000-fold selective for iNOS versus endothelial NOS dimerization in a cell-based assay. The crystal structure of inhibitor bound to the monomeric iNOS oxygenase domain revealed inhibitor-heme coordination and substantial perturbation of the substrate binding site and the dimerization interface, indicating that this small molecule acts by allosterically disrupting protein-protein interactions at the dimer interface. These results provide a mechanism-based approach to highly selective iNOS inhibition. Inhibitors were active in vivo, with ED(50) values of <2 mg/kg in a rat model of endotoxin-induced systemic iNOS induction. Thus, this class of dimerization inhibitors has broad therapeutic potential in iNOS-mediated pathologies.
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Affiliation(s)
- K McMillan
- Pharmacopeia, Inc., Princeton, NJ 08512, USA
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38
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Sono M, Ledbetter AP, McMillan K, Roman LJ, Shea TM, Masters BS, Dawson JH. Essential thiol requirement to restore pterin- or substrate-binding capability and to regenerate native enzyme-type high-spin heme spectra in the Escherichia coli-expressed tetrahydrobiopterin-free oxygenase domain of neuronal nitric oxide synthase. Biochemistry 1999; 38:15853-62. [PMID: 10625450 DOI: 10.1021/bi991580j] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nitric oxide (NO) synthases (NOS) are thiolate-ligated heme-, tetrahydrobiopterin (BH(4))-, and flavin-containing monooxygenases which catalyze the NADPH-dependent conversion of L-arginine (L-Arg) to NO AND citrulline. NOS consists of two domains: an N-terminal oxygenase (heme- and BH(4)-bound) domain and a C-terminal reductase (FMN- and FAD-bound) domain. In this study, we have spectroscopically examined the binding of L-Agr and BH(4) to the dimeric, BH(4)-free ferric neuronal NOS (NNOS) oxygenase domain expressed in Escherichia coli separately from the reductase domain. Addition of L-Arg or its analogue inhibitors (N(G)()-methyl-L-Arg, N(G)()-nitro-L-Arg) and BH(4), together with dithiothreitol (DTT), to the pterin-free ferric low-spin oxygenase domain (gamma(MAX): 419, 538, 568 NM) and incubation for 2-3 days at 4 degrees C converted the domain to a native enzyme-type, predominantly high-spin state (gamma(MAX): approximately 395, approximately 512, approximately 650 NM). 7,8-Dihydrobiopterin and other thiols (E.G., beta-mercaptoethanol, cysteine, and glutathione, with less effectiveness) can replace BH(4) and DTT, respectively. the UV-visible absorption spectrum of L-Arg-bound ferric full length NNOS, which exhibits a relatively intense band at approximately 650 NM (epsilon equals 7.5-8 MM(-)(1) CM(-)(1)) due to the presence of a neutral flavin semiquinone, can then be quantitatively reconstructed by combining the spectra of equimolar amounts of the oxygenase and reductase domains. Of particular note, the heme spin-state conversion does not occur in the absence of a thiol even after prolonged (35-48 H) incubation of the oxygenase domain with BH(4) and/or L-Arg under anaerobic conditions. Thus, DTT (or other thiols) plays a significant role(s) beyond keeping BH(4) in its reduced form, In restoring the pterin- and/or substrate-binding capability of the E. coli-expressed, BH(4) free, dimeric NNOS oxygenase domain. Our results in combination with recently available X-ray crystallography and site-directed mutagenesis data suggest that the observed DTT effects arise from the involvement of an intersubunit disulfide bond or its rearrangement in the NOS dimer.
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Affiliation(s)
- M Sono
- Department of Chemistry and Biochemistry and School of Medicine, University of South Carolina, Columbia, South Carolina 29208, USA.
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Ledbetter AP, McMillan K, Roman LJ, Masters BS, Dawson JH, Sono M. Low-temperature stabilization and spectroscopic characterization of the dioxygen complex of the ferrous neuronal nitric oxide synthase oxygenase domain. Biochemistry 1999; 38:8014-21. [PMID: 10387045 DOI: 10.1021/bi990619h] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Nitric oxide (NO), an intercellular messenger and an immuno-cytotoxic agent, is synthesized by the family of nitric oxide synthases (NOS), which are thiolate-ligated, heme-containing monooxygenases that convert L-Arg to L-citrulline and NO in a tetrahydrobiopterin (BH4)-dependent manner, using NADPH as the electron donor. The dioxygen complex of the ferrous enzyme has been proposed to be a key intermediate in the NOS catalytic cycle. In this study, we have generated a stable ferrous-O2 complex of the oxygenase domain of rat neuronal NOS (nNOS) by bubbling O2 through a solution of the dithionite-reduced enzyme at -30 degrees C in a cryogenic solvent containing 50% ethylene glycol. The most stable dioxygen complex is obtained using the oxygenase domain which has been preincubated for an extended length of time at 4 degrees C with BH4/dithiothreitol and NG-methyl-L-arginine, a substrate analogue inhibitor. The O2 complex of the nNOS oxygenase domain thus prepared exhibits UV-visible absorption (maxima at 419 and 553 nm, shoulder at approximately 585 nm) and magnetic circular dichroism spectra that are nearly identical to those of ferrous-O2 cytochrome P450-CAM. Our spectral data are noticeably blue-shifted from those seen at 10 degrees C for a short-lived transient species (lambdamax = 427 nm) for the nNOS oxygenase domain using stopped-flow rapid-scanning spectroscopy [Abu-Soud, H. M., Gachhui, R., Raushel, F. M., and Stuehr, D. J. (1997) J. Biol. Chem. 272, 17349], but somewhat similar to those of a relatively stable O2 adduct of L-Arg-free full-length nNOS (lambdamax = 415-416.5 nm) generated at -30 degrees C [Bec, N., Gorren, A. C. F., Voelder, C., Mayer, B., and Lange, R. (1998) J. Biol. Chem. 273, 13502]. Compared with ferrous-O2 P450-CAM, however, the ferrous-O2 adduct of the nNOS oxygenase domain is considerably more autoxidizable and the O2-CO exchange reaction is noticeably slower. The generation of a stable ferrous-O2 adduct of the nNOS oxygenase domain, as described herein, will facilitate further mechanistic and spectroscopic investigations of this important intermediate.
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Affiliation(s)
- A P Ledbetter
- Department of Chemistry and Biochemistry, School of Medicine, University of South Carolina, Columbia 29208, USA
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McMillan K, Perepelitsyn I, Wang Z, Shapshay SM. Tumor growth inhibition and regression induced by photothermal vascular targeting and angiogenesis inhibitor retinoic acid. Cancer Lett 1999; 137:35-44. [PMID: 10376792 DOI: 10.1016/s0304-3835(98)00339-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The effect of photothermal vascular targeting, alone and in combination with antiangiogenic therapy, was evaluated using tumors produced in mice by transplantation of KB cells. Tumor growth inhibition and regression followed vascular damage produced by pulsed dye laser (PDL) radiation. Administration of the antiangiogenic agent all-trans-retinoic acid (RA) was associated with smaller average tumor volumes in the presence and absence of PDL irradiation, but this effect was not statistically significant. The ability of PDL photothermal vascular targeting to cause regression of tumors without harming normal tissue may be a consequence of preferential damage to supplying vessels at the tumor periphery.
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Affiliation(s)
- K McMillan
- Otolaryngology Research Center, Department of Otolaryngology, Head & Neck Surgery, New England Medical Center, Boston, MA 02111, USA.
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Abstract
OBJECTIVES/HYPOTHESIS Standard management of recurrent respiratory papillomatosis (RRP) currently consists of CO2 laser microsurgical ablation of papillomas. Because of the recurrent nature of this viral disease, patients are often faced with significant cumulative risk of soft tissue complications. As a minimally traumatic alternative to management of RRP, we have investigated the use of the 585-nm pulsed dye laser (PDL) to cause regression of papillomas by selective eradication of the tumor microvasculature. STUDY DESIGN Nonrandomized prospective pilot study. METHODS Patients with laryngeal papillomas were treated with the PDL at fluences of 6 J/cm2 (double pulses per irradiated site), 8 J/cm2 (single pulses), and 10 J/cm2 (single pulses), at noncritical areas within the larynx, using a specially designed micromanipulator. Lesions on the true cords were treated with the CO2 laser, using standard methodology. RESULTS Clinical examination of three patients treated to date showed that PDL treatment appeared to produce complete regression of papillomas. Unlike the sites of lesions treated by the CO2 laser, the epithelial surface at the PDL treatment sites was preserved intact. CONCLUSIONS These preliminary results suggest the PDL may eradicate respiratory papillomas with minimal damage to normal laryngeal tissue. Further analysis of the ongoing study is required to demonstrate potential benefits of the technique.
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Affiliation(s)
- K McMillan
- Otolaryngology Research Center, Department of Otolaryngology, New England Medical Center, Boston, Massachusetts 02111, USA.
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42
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Dhingra JK, Zhang X, McMillan K, Kabani S, Manoharan R, Itzkan I, Feld MS, Shapshay SM. Diagnosis of head and neck precancerous lesions in an animal model using fluorescence spectroscopy. Laryngoscope 1998; 108:471-5. [PMID: 9546254 DOI: 10.1097/00005537-199804000-00002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Laser-induced fluorescence (LIF) of tissues depends on their biochemical and histomorphologic characteristics. LIF spectroscopic properties of 9,10-dimethyl-1,2-benzanthracene (DMBA)-induced precancerous and early cancerous lesions in a hamster buccal pouch mucosa model were studied. Fluorescence spectra from neoplastic lesions showed a characteristic fluorescence peak in the red region of the visible spectrum centered between 630 and 640 nm when excited with 410-nm light. Using this as a diagnostic criterion, 45 of 49 lesions studied were correctly diagnosed, including early dysplastic lesions. Follow-up study of four dysplastic lesions over 2 weeks revealed an increase in red fluorescence intensity. The findings of these experiments suggest that LIF spectroscopy may be a valuable noninvasive technique not only for early diagnosis of head and neck cancer, but also to probe a possible biochemical surrogate biomarker in the follow-up of suspected lesions.
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MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/adverse effects
- Animals
- Biomarkers, Tumor/analysis
- Carcinogens/adverse effects
- Carcinoma in Situ/chemically induced
- Carcinoma in Situ/diagnosis
- Carcinoma in Situ/metabolism
- Carcinoma in Situ/pathology
- Carcinoma, Squamous Cell/chemically induced
- Carcinoma, Squamous Cell/diagnosis
- Carcinoma, Squamous Cell/metabolism
- Carcinoma, Squamous Cell/pathology
- Cell Transformation, Neoplastic/chemically induced
- Cell Transformation, Neoplastic/metabolism
- Cell Transformation, Neoplastic/pathology
- Color
- Cricetinae
- Disease Models, Animal
- Disease Progression
- Fluorescence
- Follow-Up Studies
- Hyperplasia
- Lasers
- Leukoplakia, Oral/chemically induced
- Leukoplakia, Oral/diagnosis
- Leukoplakia, Oral/metabolism
- Leukoplakia, Oral/pathology
- Male
- Mesocricetus
- Mouth Mucosa/drug effects
- Mouth Mucosa/metabolism
- Mouth Mucosa/pathology
- Mouth Neoplasms/chemically induced
- Mouth Neoplasms/diagnosis
- Mouth Neoplasms/metabolism
- Mouth Neoplasms/pathology
- Neoplasm Invasiveness
- Precancerous Conditions/chemically induced
- Precancerous Conditions/diagnosis
- Precancerous Conditions/metabolism
- Precancerous Conditions/pathology
- Spectrometry, Fluorescence
- Stomatitis/chemically induced
- Stomatitis/diagnosis
- Stomatitis/metabolism
- Stomatitis/pathology
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Affiliation(s)
- J K Dhingra
- Department of Otolaryngology Head and Neck Surgery, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
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Migita CT, Salerno JC, Masters BS, Martasek P, McMillan K, Ikeda-Saito M. Substrate binding-induced changes in the EPR spectra of the ferrous nitric oxide complexes of neuronal nitric oxide synthase. Biochemistry 1997; 36:10987-92. [PMID: 9283090 DOI: 10.1021/bi970823+] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A versatile diatomic physiological messenger, nitric oxide (NO), is biosynthesized by a group of flavo-heme enzymes, the nitric oxide synthases. We have examined the active site of the neuronal isoform by EPR spectroscopy of the ferrous nitric oxide complex. The nitric oxide complex of the substrate-free enzyme exhibits a cytochrome P450-type EPR spectrum typical of a hexacoordinate NO-heme complex with a non-nitrogenous proximal axial heme ligand. The NO complex of the substrate-free enzyme is rather unstable and spontaneously converts to a cytochrome P420 type pentacoordinate denatured form. Binding of L-arginine (l-Arg) enhances the stability of the hexacoordinate NO form. The EPR spectrum of the NO adduct of the enzyme-substrate complex has an increased g-anisotropy and well-resolved hyperfine couplings due to the 14N of nitric oxide. Significant perturbations in the NO EPR spectrum were observed upon Nomega-monomethyl-L-Arg and Nomega-hydroxy-L-Arg binding. The perturbations in the EPR spectrum indicate that L-Arg and its derivatives bind on the distal site of the heme in very close proximity to the bound NO to cause alterations in the heme-NO coordination structure. Interactions between the bound NO and the substrate or its analogues appear to affect the Fe-NO geometry, resulting in the observed spectral changes. We infer that analogous interactions with oxygen might be involved in the hydroxylation events during enzyme catalysis of nitric oxide synthase.
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Affiliation(s)
- C T Migita
- Department of Physiology and Biophysics, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106-4970, USA
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Waldorf HA, Alster TS, McMillan K, Kauvar AN, Geronemus RG, Nelson JS. Effect of dynamic cooling on 585-nm pulsed dye laser treatment of port-wine stain birthmarks. Dermatol Surg 1997; 23:657-62. [PMID: 9256912 DOI: 10.1111/j.1524-4725.1997.tb00385.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND AND OBJECTIVE The objective of this study was to determine the effectiveness of a dynamic cooling device (DCD), spraying the skin with a brief spurt of cryogen prior to the laser pulse, in reducing transient pain associated with 585-nm pulsed dye laser (PDL) treatment of port-wine stains (PWS), and reducing epidermal damage (hypo/hyperpigmentation) caused by this laser during PWS treatment. MATERIALS AND METHODS Matched treatment sites were compared with and without the use of the cryogen spray in 47 patients at two investigational sites. Pain ratings, clearance of the PWS, and pigmentation changes were assessed. The results were analyzed by skin type and patient age. RESULTS A statistically significant reduction in pain ratings was found in all patient groups using the DCD without changing the efficacy of PWS clearance. Pain reduction was most remarkable in patients with darker skin types. Dynamic cooling prevented the occurrence of epidermal damage or pigmentation change in most cases. CONCLUSIONS This study suggests that dynamic cooling can dramatically diminish pain during PWS treatment with the 585-nm PDL without reducing treatment efficacy. The absence of epidermal damage in most patients suggests that precooling with the DCD may allow the use of higher laser fluences to expedite clearance without inducing epidermal change. Dynamic cooling has potential use with other lasers and different lesions where discomfort and epidermal effects limit therapy.
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Affiliation(s)
- H A Waldorf
- Laser and Skin Surgery Center of New York, NY 10016, USA
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45
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Narayanasami R, Nishimura JS, McMillan K, Roman LJ, Shea TM, Robida AM, Horowitz PM, Masters BS. The influence of chaotropic reagents on neuronal nitric oxide synthase and its flavoprotein module. Urea and guanidine hydrochloride stimulate NADPH-cytochrome c reductase activity of both proteins. Nitric Oxide 1997; 1:39-49. [PMID: 9701043 DOI: 10.1006/niox.1996.0103] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Changes in flavin and protein fluorescence of neuronal nitric oxide synthase (nNOS) and its flavoprotein module were studied in the presence of urea and compared with those previously reported for cytochrome P450 reductase (CPR) [R. Narayanasami, P. M. Horowitz, and B. S. S. Masters (1995) Arch. Biochem. Biophys. 316, 267-274]. As in the case of CPR, FMN was relatively loosely bound to nNOS and the flavoprotein module, but FAD remained bound at concentrations of up to 2 M urea Protein fluorescence increased progressively with increasing urea concentration, but could not be correlated with changes in flavin binding. NADPH-cytochrome c reductase activity of both nNOS and the flavoprotein module, but not that of CPR, was stimulated at early time points by both urea and guanidine hydrochloride (GnHCl), with levels of initial activity returning to baseline values within 60 min after addition of the chaotropic agent. Thus, at 3-4 M urea, enhancements of reductase activities of 20- and 5-fold with nNOS and the flavoprotein module, respectively, were obtained. Comparable enhancements of 12- and 6- to 7-fold, respectively, were obtained with calmodulin (CaM)/ CaCl2 and 0.5 M GnHCl. Thus, the effects of urea and GnHCl mimicked the stimulating effects of CaM. Separate preincubations of nNOS and cytochrome c with urea or GnHCl prior to initiation of the reductase assay showed that sensitivity to chaotropic agent under these conditions was a property of nNOS and not of cytochrome c. Moreover, when the nonprotein electron acceptor 2,6-dichlorophenolindophenol was employed in place of cytochrome c, comparable stimulation of reductase activity was observed in the presence of either urea or GnHCl. Fluorescence of 4,4'-dianilino-1,1'-binaphthyl-5,5'-disulfate in the presence of either nNOS or the flavoprotein module was increased optimally between 3 and 4 M urea, consistent with simultaneous exposure of hydrophobic regions of both proteins to solvent and optimization of reductase activity. FMN release from nNOS, but not from the flavoprotein module, was enhanced by CaM. Addition of FMN or FMN + FAD to nNOS, in the presence or absence of urea, brought about a doubling of initial cytochrome c reductase activity, but did not prevent the eventual decline in activity to basal levels. These data are consistent with conformational changes which favor increased electron transfer similar to that achieved with nNOS in the presence of CaM.
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Affiliation(s)
- R Narayanasami
- Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284-7760, USA
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Dhingra JK, Perrault DF, McMillan K, Rebeiz EE, Kabani S, Manoharan R, Itzkan I, Feld MS, Shapshay SM. Early diagnosis of upper aerodigestive tract cancer by autofluorescence. Arch Otolaryngol Head Neck Surg 1996; 122:1181-6. [PMID: 8906052 DOI: 10.1001/archotol.1996.01890230029007] [Citation(s) in RCA: 82] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To explore the potential of autofluorescence spectroscopy as a tool for early detection of upper aerodigestive tract cancer. DESIGN Autofluorescence spectral characteristics of 19 untreated oral and oropharyngeal lesions in 13 patients were studied with excitation wavelengths of 370 and 410 nm generated by a nitrogen pumped dye laser. Ten healthy volunteers were recruited to characterize the fluorescence spectra of normal mucosa at different oral sites and to study individual variations. Fluorescence intensity and line shape of the spectra from lesions were compared with the same parameters from the contralateral control site in the same individual. SETTING Otolaryngology Research Center, Department of Otolaryngology-Head and Neck Surgery, New England Medical Center, Boston, Mass. RESULTS The ratio of peak fluorescence intensities of the neoplastic lesions to contralateral normal control mucosa were consistently different compared with these ratios in benign lesions or normal mucosa. These differences were seen in 2 distinct regions of the fluorescence spectrum with both of the excitation wavelengths, but were more obvious with the excitation wavelength of 410 nm. Using these differences, we were able to correctly diagnose 17 of the 19 lesions studied, with 2 false-positive results. CONCLUSIONS Neoplastic oral mucosa shows consistent differences in autofluorescence spectral intensity and line shape when compared with the normal mucosa in the same individual. These early results show that fluorescence spectroscopy may represent a useful technique for noninvasive early diagnosis of cancer of the upper aerodigestive tract.
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Affiliation(s)
- J K Dhingra
- Department of Otolaryngology-Head and Neck Surgery, New England Medical Center, Tufts University, Boston, Mass, USA
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Affiliation(s)
- K McMillan
- Department of Clinical Pharmacy, College of Pharmacy, University of Tennessee, Memphis 38163, USA.
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Salerno JC, McMillan K, Masters BS. Binding of intermediate, product, and substrate analogs to neuronal nitric oxide synthase: ferriheme is sensitive to ligand-specific effects in the L-arginine binding site. Biochemistry 1996; 35:11839-45. [PMID: 8794766 DOI: 10.1021/bi953015w] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The electron paramagnetic resonance spectra of purified neuronal nitric oxide synthase indicates that the binding of ligands to the arginine site perturbs the environment of the high-spin ferriheme in a highly ligand-specific manner. Four categories of high-spin complex can be distinguished; all are five-coordinate, and all retain the axial thiolate ligand, but they differ in their ligation geometries. These spectroscopic species reveal distinct local conformations which can be stabilized individually by the binding of L-arginine, N omega-hydroxy-L-arginine, N omega-methyl-L-arginine, and N omega-nitro-L-arginine. Other arginine analog inhibitors stabilize one or more of these states, revealing patterns based on the nature of substituents at the terminal amino group.
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Affiliation(s)
- J C Salerno
- Department of Biochemistry, University of Texas Health Science Center, San Antonio 78284-7760, USA
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Chang WJ, Iannaccone ST, Lau KS, Masters BS, McCabe TJ, McMillan K, Padre RC, Spencer MJ, Tidball JG, Stull JT. Neuronal nitric oxide synthase and dystrophin-deficient muscular dystrophy. Proc Natl Acad Sci U S A 1996; 93:9142-7. [PMID: 8799168 PMCID: PMC38609 DOI: 10.1073/pnas.93.17.9142] [Citation(s) in RCA: 283] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Neuronal nitric oxide synthase (nNOS) in fast-twitch skeletal muscle fibers is primarily particulate in contrast to its greater solubility in brain. Immunohistochemistry shows nNOS localized to the sarcolemma, with enrichment at force transmitting sites, the myotendinous junctions, and costameres. Because this distribution is similar to dystrophin, we determined if nNOS expression was affected by the loss of dystrophin. Significant nNOS immunoreactivity and enzyme activity was absent in skeletal muscle tissues from patients with Duchenne muscular dystrophy. Similarly, in dystrophin-deficient skeletal muscles from mdx mice both soluble and particulate nNOS was greatly reduced compared with C57 control mice. nNOS mRNA was also reduced in mdx muscle in contrast to mRNA levels for a dystrophin binding protein, alpha 1-syntrophin. nNOS levels increased dramatically from 2 to 52 weeks of age in C57 skeletal muscle, which may indicate a physiological role for NO in aging-related processes. Biochemical purification readily dissociates nNOS from the dystrophin-glycoprotein complex. Thus, nNOS is not an integral component of the dystrophin-glycoprotein complex and is not simply another dystrophin-associated protein since the expression of both nNOS mRNA and protein is affected by dystrophin expression.
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Affiliation(s)
- W J Chang
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235, USA
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Masters BS, McMillan K, Sheta EA, Nishimura JS, Roman LJ, Martasek P. Neuronal nitric oxide synthase, a modular enzyme formed by convergent evolution: structure studies of a cysteine thiolate-liganded heme protein that hydroxylates L-arginine to produce NO. as a cellular signal. FASEB J 1996; 10:552-8. [PMID: 8621055 DOI: 10.1096/fasebj.10.5.8621055] [Citation(s) in RCA: 144] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The nitric oxide synthases (NOS-I, neuronal, NOS-II, inducible, and NOS-III, endothelial) are the most recent additions to the large number of heme proteins that contain cysteine thiolate-liganded protoporphyrin IX heme prosthetic groups. This group of oxygenating enzymes also includes one of the largest gene families, that of the cytochromes P450, which have been demonstrated to be involved in the hydroxylation of a variety of substrates, including endogenous compounds (steroids, fatty acids, and prostaglandins) and exogenous compounds (therapeutic drugs, environmental toxicants, and carcinogens). The substrates for cytochromes P450 are universally hydrophobic while the physiological substrate for the nitric oxide synthases is the amino acid L-arginine, a hydrophilic compound. This review will discuss the approaches being used to study the structure and mechanism of neuronal nitric oxide synthase in the context of its known prosthetic groups and regulation by Ca(2+)-calmodulin and/or tetrahydrobiopterin (BH4).
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Affiliation(s)
- B S Masters
- Department of Biochemistry, University of Texas Health Science Center at San Antonio 78284-7760, USA
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