1
|
Tekendo-Ngongang C, Williams KJ, Williams MS. Cross-cultural representations of conjoined twins. Am J Med Genet C Semin Med Genet 2021; 187:240-253. [PMID: 33982866 DOI: 10.1002/ajmg.c.31897] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/19/2021] [Accepted: 03/03/2021] [Indexed: 11/08/2022]
Abstract
Conjoined twinning is a rare birth defect estimated to occur in about 1 in 50,000 to 100,000 births. The mechanism of conjoined twinning is not proven. Different forms of conjoined twinning are observed with the thoracopagus form being the most common. The rate of conjoined twinning is similar across all major populations. A dramatic malformation of this type would be an extraordinary occurrence leading people to reflect on the spiritual or supernatural nature of such an event. Therefore, it is not surprising that artifacts that seem to depict different forms of conjoined twins are seen across diverse cultures. In this article, we present a survey of these cultural artifacts including anatomic classification based on external anatomy and an exploration of the cultural and spiritual contexts associated with the artifacts. A key finding is that the most common form of conjoined twinning in the artifacts is parapagus (both dicephalus and diprosopus) in contrast to thoracopagus, the most common form in epidemiologic studies. Potential reasons for this difference are discussed. Evidence is presented to support the speculation that these objects represent artistic impressions of actual conjoined twinning events.
Collapse
Affiliation(s)
- Cedrik Tekendo-Ngongang
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland, USA
| | - Keith J Williams
- Department of Art and Design, Concordia University, St. Paul, Minnesota, USA
| | - Marc S Williams
- Genomic Medicine Institute-Geisinger, Danville, Pennsylvania, USA
| |
Collapse
|
2
|
Vazquez T, Feng R, Williams KJ, Werth VP. Immunological and clinical heterogeneity in cutaneous lupus erythematosus. Br J Dermatol 2021; 185:480-481. [PMID: 33966286 DOI: 10.1111/bjd.20085] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 03/01/2021] [Indexed: 11/30/2022]
Affiliation(s)
- T Vazquez
- Corporal Michael J. Crescenz VAMC, Philadelphia, PA, USA.,Department of Dermatology, University of Pennsylvania, Philadelphia, PA, USA
| | - R Feng
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - K J Williams
- Department of Physiology, Department of Medicine, Lewis Katz School of Medicine at Temple University, University of Pennsylvania, Philadelphia, PA, USA
| | - V P Werth
- Corporal Michael J. Crescenz VAMC, Philadelphia, PA, USA.,Department of Dermatology, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
3
|
Jamali Mahabadi SE, Carruthers TF, Menyuk CR, McKinney JD, Williams KJ. Impact of nonlinearity including bleaching in MUTC photodetectors on RF-modulated electro-optic frequency combs. Opt Express 2021; 29:11520-11532. [PMID: 33984929 DOI: 10.1364/oe.420096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
We use the drift-diffusion equations to calculate the responsivity of a modified uni-traveling carrier (MUTC) photodetector (PD) with a frequency comb input that is generated by a series of short optical pulses. We first use experimental results for the responsivity of the MUTC PD to obtain an empirical model of bleaching in pulsed mode. We incorporate our empirical bleaching model into a drift-diffusion model to calculate the impact of nonlinearity in an MUTC PD on RF-modulated electro-optic frequency combs. We quantify the nonlinearity using the second- and third-order intermodulation distortion powers (IMD2 and IMD3), from which we calculate the second- and third-order output intercept points (OIP2 and OIP3). In contrast to a continuous wave (CW) input for which there is a single IMD2 and IMD3 and hence a single OIP2 and OIP3, each comb line n has its own IMD2n, IMD3n, OIP2n, and OIP3n associated with it. We determine the IMD2n, IMD3n, OIP2n, and OIP3n, and we compare the results with and without bleaching. We find that the impact of bleaching is complex and, somewhat surprisingly, not always detrimental. The principal effect of bleaching is to lower the responsivity, which decreases the nonlinearity due to space charge. While bleaching always reduces the OIP2n and OIP3n, we find that bleaching leads to a decreased distortion-to-signal ratio for large n.
Collapse
|
4
|
Jamali Mahabadi SE, Carruthers TF, Menyuk CR, McKinney JD, Williams KJ. Comparison of the impact of nonlinearity in a p-i-n and an MUTC photodetector on electro-optic frequency combs. Opt Lett 2021; 46:813-816. [PMID: 33577529 DOI: 10.1364/ol.414026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Accepted: 12/31/2020] [Indexed: 06/12/2023]
Abstract
We calculate the impact of nonlinearity in both a p-i-n photodetector (PD) and a modified uni-traveling carrier (MUTC) PD on an RF-modulated frequency comb generated using 100-fs optical pulses with a 50-MHz repetition rate. We take into account bleaching (nonlinear saturation) that is due to the high peak-to-average-power ratio and contributes to the device nonlinearity. Nonlinear impairment of an RF-modulated continuous wave is typically characterized by the second- and third-order intermodulation distortion products (IMD2 and IMD3). In contrast, an RF-modulated frequency comb must be characterized by a distinct IMD2n and IMD3n for each comb line n. We calculate IMD2n and IMD3n in both p-i-n and MUTC PDs and compare the results. We also calculate the ratio of the IMD2n power and the IMD3n power to the fundamental power Sin in both p-i-n and MUTC PDs. We find that nonlinear distortion has a greater impact at high frequencies in the MUTC PD than in the p-i-n PD.
Collapse
|
5
|
Marti FEM, Jayson GC, Manoharan P, O'Connor J, Renehan AG, Backen AC, Mistry H, Ortega F, Li K, Simpson KL, Allen J, Connell J, Underhill S, Misra V, Williams KJ, Stratford I, Jackson A, Dive C, Saunders MP. Novel phase I trial design to evaluate the addition of cediranib or selumetinib to preoperative chemoradiotherapy for locally advanced rectal cancer: the DREAMtherapy trial. Eur J Cancer 2019; 117:48-59. [PMID: 31229949 DOI: 10.1016/j.ejca.2019.04.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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] [Received: 03/21/2019] [Accepted: 04/21/2019] [Indexed: 10/26/2022]
Abstract
BACKGROUND The DREAMtherapy (Dual REctal Angiogenesis MEK inhibition radiotherapy) trial is a novel intertwined design whereby two tyrosine kinase inhibitors (cediranib and selumetinib) were independently evaluated with rectal chemoradiotherapy (CRT) in an efficient manner to limit the extended follow-up period often required for radiotherapy studies. PATIENTS AND METHODS Cediranib or selumetinib was commenced 10 days before and then continued with RT (45 Gy/25#/5 wks) and capecitabine (825 mg/m2 twice a day (BID)). When three patients in the cediranib 15-mg once daily (OD) cohort were in the surveillance period, recruitment to the selumetinib cohort commenced. This alternating schedule was followed throughout. Three cediranib (15, 20 and 30 mg OD) and two selumetinib cohorts (50 and 75 mg BID) were planned. Circulating and imaging biomarkers of inflammation/angiogenesis were evaluated. RESULTS In case of cediranib, dose-limiting diarrhoea, fatigue and skin reactions were seen in the 30-mg OD cohort, and therefore, 20 mg OD was defined as the maximum tolerated dose. Forty-one percent patients achieved a clinical or pathological complete response (7/17), and 53% (9/17) had an excellent clinical or pathological response (ECPR). Significantly lower level of pre-treatment plasma tumour necrosis factor alpha (TNFα) was found in patients who had an ECPR. In case of selumetinib, the 50-mg BID cohort was poorly tolerated (fatigue and diarrhoea); a reduced dose cohort of 75-mg OD was opened which was also poorly tolerated, and further recruitment was abandoned. Of the 12 patients treated, two attained an ECPR (17%). CONCLUSIONS This novel intertwined trial design is an effective way to independently investigate multiple agents with radiotherapy. The combination of cediranib with CRT was well tolerated with encouraging efficacy. TNFα emerged as a potential predictive biomarker of response and warrants further evaluation.
Collapse
Affiliation(s)
| | - G C Jayson
- The Christie NHS Foundation Trust, Manchester, UK; Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - P Manoharan
- The Christie NHS Foundation Trust, Manchester, UK; Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - J O'Connor
- The Christie NHS Foundation Trust, Manchester, UK; Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - A G Renehan
- The Christie NHS Foundation Trust, Manchester, UK; Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - A C Backen
- The Christie NHS Foundation Trust, Manchester, UK; Division of Cancer Sciences, School of Medical Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - H Mistry
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - F Ortega
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - K Li
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - K L Simpson
- Clinical and Experimental Pharmacology Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
| | - J Allen
- The Christie NHS Foundation Trust, Manchester, UK
| | - J Connell
- The Christie NHS Foundation Trust, Manchester, UK
| | - S Underhill
- The Christie NHS Foundation Trust, Manchester, UK
| | - V Misra
- The Christie NHS Foundation Trust, Manchester, UK
| | - K J Williams
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK; Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - I Stratford
- Division of Pharmacy and Optometry, School of Health Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, M13 9PT, UK
| | - A Jackson
- Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
| | - C Dive
- Clinical and Experimental Pharmacology Group, Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK
| | - M P Saunders
- The Christie NHS Foundation Trust, Manchester, UK.
| |
Collapse
|
6
|
Mahabadi SEJ, Wang S, Carruthers TF, Menyuk CR, Quinlan FJ, Hutchinson MN, McKinney JD, Williams KJ. Calculation of the impulse response and phase noise of a high-current photodetector using the drift-diffusion equations. Opt Express 2019; 27:3717-3730. [PMID: 30732387 DOI: 10.1364/oe.27.003717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/03/2019] [Indexed: 06/09/2023]
Abstract
We describe a procedure to calculate the impulse response and phase noise of high-current photodetectors using the drift-diffusion equations while avoiding computationally expensive Monte Carlo simulations. We apply this procedure to a modified uni-traveling-carrier (MUTC) photodetector. In our approach, we first use the full drift-diffusion equations to calculate the steady-state photodetector parameters. We then perturb the generation rate as a function of time to calculate the impulse response. We next calculate the fundamental shot noise limit and cut-off frequency of the device. We find the contributions of the electron, hole, and displacement currents. We calculate the phase noise of an MUTC photodetector. We find good agreement with experimental and Monte Carlo simulation results. We show that phase noise is minimized by having an impulse response with a tail that is as small as possible. Since, our approach is much faster computationally than Monte Carlo simulations, we are able to carry out a broad parameter study to optimize the device performance. We propose a new optimized structure with less phase noise and reduced nonlinearity.
Collapse
|
7
|
Tar PD, Thacker NA, Babur M, Watson Y, Cheung S, Little RA, Gieling RG, Williams KJ, O’Connor JPB. A new method for the high-precision assessment of tumor changes in response to treatment. Bioinformatics 2018; 34:2625-2633. [PMID: 29547950 PMCID: PMC6061877 DOI: 10.1093/bioinformatics/bty115] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 02/05/2018] [Accepted: 03/12/2018] [Indexed: 11/12/2022] Open
Abstract
Motivation Imaging demonstrates that preclinical and human tumors are heterogeneous, i.e. a single tumor can exhibit multiple regions that behave differently during both development and also in response to treatment. The large variations observed in control group, tumors can obscure detection of significant therapeutic effects due to the ambiguity in attributing causes of change. This can hinder development of effective therapies due to limitations in experimental design rather than due to therapeutic failure. An improved method to model biological variation and heterogeneity in imaging signals is described. Specifically, linear Poisson modeling (LPM) evaluates changes in apparent diffusion co-efficient between baseline and 72 h after radiotherapy, in two xenograft models of colorectal cancer. The statistical significance of measured changes is compared to those attainable using a conventional t-test analysis on basic apparent diffusion co-efficient distribution parameters. Results When LPMs were applied to treated tumors, the LPMs detected highly significant changes. The analyses were significant for all tumors, equating to a gain in power of 4-fold (i.e. equivalent to having a sample size 16 times larger), compared with the conventional approach. In contrast, highly significant changes are only detected at a cohort level using t-tests, restricting their potential use within personalized medicine and increasing the number of animals required during testing. Furthermore, LPM enabled the relative volumes of responding and non-responding tissue to be estimated for each xenograft model. Leave-one-out analysis of the treated xenografts provided quality control and identified potential outliers, raising confidence in LPM data at clinically relevant sample sizes. Availability and implementation TINA Vision open source software is available from www.tina-vision.net. Supplementary information Supplementary data are available at Bioinformatics online.
Collapse
Affiliation(s)
- P D Tar
- Division of Informatics, Imaging and Data Science, Manchester Pharmacy School, Manchester, UK
| | - N A Thacker
- Division of Informatics, Imaging and Data Science, Manchester Pharmacy School, Manchester, UK
| | - M Babur
- Division of Pharmacy and Optometry, Manchester Pharmacy School, Manchester, UK
| | - Y Watson
- Division of Informatics, Imaging and Data Science, Manchester Pharmacy School, Manchester, UK
| | - S Cheung
- Division of Informatics, Imaging and Data Science, Manchester Pharmacy School, Manchester, UK
| | - R A Little
- Division of Informatics, Imaging and Data Science, Manchester Pharmacy School, Manchester, UK
| | - R G Gieling
- Division of Pharmacy and Optometry, Manchester Pharmacy School, Manchester, UK
| | - K J Williams
- Division of Pharmacy and Optometry, Manchester Pharmacy School, Manchester, UK
- Division of Cancer Sciences, University of Manchester
| | - J P B O’Connor
- Division of Cancer Sciences, University of Manchester
- Department of Radiology, The Christie Hospital NHS Trust, Manchester, UK
| |
Collapse
|
8
|
Morris O, Elsawy MA, Fairclough M, Williams KJ, Mcmahon A, Grigg J, Forster D, Miller AF, Saiani A, Prenant C. In vivo characterisation of a therapeutically relevant self-assembling 18 F-labelled β-sheet forming peptide and its hydrogel using positron emission tomography. J Labelled Comp Radiopharm 2017. [PMID: 28623878 PMCID: PMC5601235 DOI: 10.1002/jlcr.3534] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Positron emission tomography (PET) and fluorescence labelling have been used to assess the pharmacokinetics, biodistribution and eventual fate of a hydrogel‐forming nonapeptide, FEFKFEFKK (F9), in healthy mice, using 18F‐labelled and fluorescein isothiocyanate (FITC)‐labelled F9 analogues. F9 was site‐specifically radiolabelled with 2‐[18F]fluoro‐3‐pyridinecarboxaldehyde ([18F]FPCA) via oxime bond formation. [18F]FPCA‐F9 in vivo fate was evaluated both as a solution, following intravenous administration, and as a hydrogel when subcutaneously injected. The behaviour of FITC‐F9 hydrogel was assessed following subcutaneous injection. [18F]FPCA‐F9 demonstrated high plasma stability and primarily renal excretion; [18F]FPCA‐F9 when in solution and injected into the bloodstream displayed prompt bladder uptake (53.4 ± 16.6 SUV at 20 minutes postinjection) and rapid renal excretion, whereas [18F]FPCA‐F9 hydrogel, formed by co‐assembly of [18F]FPCA‐F9 monomer with unfunctionalised F9 peptide and injected subcutaneously, showed gradual bladder accumulation of hydrogel fragments (3.8 ± 0.4 SUV at 20 minutes postinjection), resulting in slower renal excretion. Gradual disaggregation of the F9 hydrogel from the site of injection was monitored using FITC‐F9 hydrogel in healthy mice (60 ± 3 over 96 hours), indicating a biological half‐life between 1 and 4 days. The in vivo characterisation of F9, both as a gel and a solution, highlights its potential as a biomaterial.
Collapse
Affiliation(s)
- O Morris
- Wolfson Molecular Imaging Centre, The University of Manchester, UK.,CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK
| | - M A Elsawy
- School of Materials, The University of Manchester, UK.,Manchester Institute of Biotechnology, The University of Manchester, UK.,School of Pharmacy and Biomedical Sciences, University of Central Lancashire, UK
| | - M Fairclough
- Wolfson Molecular Imaging Centre, The University of Manchester, UK.,CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK
| | - K J Williams
- CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK.,Manchester Pharmacy School, The University of Manchester, UK
| | - A Mcmahon
- Wolfson Molecular Imaging Centre, The University of Manchester, UK.,CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK
| | - J Grigg
- GE Healthcare, Little Chalfont, UK
| | - D Forster
- Wolfson Molecular Imaging Centre, The University of Manchester, UK.,CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK
| | - A F Miller
- Manchester Institute of Biotechnology, The University of Manchester, UK.,School of Chemical Engineering and Analytical Science, The University of Manchester, UK
| | - A Saiani
- School of Materials, The University of Manchester, UK.,Manchester Institute of Biotechnology, The University of Manchester, UK.,School of Chemical Engineering and Analytical Science, The University of Manchester, UK
| | - C Prenant
- Wolfson Molecular Imaging Centre, The University of Manchester, UK.,CRUK/EPSRC Imaging Centre in Cambridge & Manchester, The University of Manchester, UK
| |
Collapse
|
9
|
Jaffey JA, Williams KJ, Masseau I, Krueger M, Reinero C. Vasoproliferative process resembling pulmonary capillary hemangiomatosis in a cat. BMC Vet Res 2017; 13:72. [PMID: 28320395 PMCID: PMC5359803 DOI: 10.1186/s12917-017-0984-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 02/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Pulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species. CASE PRESENTATION A 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis. CONCLUSION This is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.
Collapse
Affiliation(s)
- J A Jaffey
- University of Missouri Veterinary Health Center, Columbia, MO, USA
| | - K J Williams
- Michigan State University, East Lansing, MI, USA
| | - I Masseau
- Université de Montréal, St-Hyacinthe, Québec, Canada
| | - M Krueger
- Veterinary Specialty Hopsital of Hong Kong, Wan Chai, Hong Kong
| | - C Reinero
- University of Missouri Veterinary Health Center, Columbia, MO, USA.
| |
Collapse
|
10
|
Hu Y, Menyuk CR, Hutchinson MN, Urick VJ, Williams KJ. Frequency dependent harmonic powers in a modified uni-traveling carrier photodetector. Opt Lett 2017; 42:919-922. [PMID: 28248331 DOI: 10.1364/ol.42.000919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We use a drift-diffusion model to study frequency dependent harmonic powers in a modified uni-traveling carrier (MUTC) phododetector. The model includes external loading, incomplete ionization, the Franz-Keldysh effect, and history-dependent impact ionization. In three-tone measurements, the bias voltage at which a null occurs (bias null) in the second-order intermodulation distortion (IMD2) is different for the sum frequency and difference frequency. We obtained agreement with the experimental results. The bias null that appears in the IMD2 is due to the Franz-Keldysh effect. The bias voltage at which the bias null is located depends on the electric field in the intrinsic region, and the difference in the location of the bias null for the sum frequency and difference frequency is due to the displacement current in the intrinsic region. When the frequency is large, the displacement current is large and has a large effect on the harmonic powers. We also found that the bias null depends on the recombination rate in the p-absorption region because the electric field decreases in the intrinsic region when the recombination rate in the p-region decreases.
Collapse
|
11
|
Abstract
Myocardial ischemia, an uncommon cause of sudden death in dogs, usually results in infarction and fibrosis of the myocardium. Necropsy examination of a 13-year-old German Shepherd dog that died suddenly demonstrated multifocal myocardial thinning and loss in the left and right ventricular free wall and right atrium. Histopathologic examination confirmed the myocardial thinning to be sites of myocyte atrophy and loss, with loose reticulin-positive fibrovascular tissue and adipocytes and little fibrosis. Many intramural coronary arteries were irregularly thickened and partially occluded by segmental intimal and medial deposits of periodic acid-Schiff-positive, Congo red-negative amorphous extracellular material. This finding is consistent with hyaline arteriosclerosis. These vascular lesions likely lead to insufficient perfusion of the affected myocardium and gradual loss of myofibers without the acute necrosis and fibrosis characteristic of infarction.
Collapse
Affiliation(s)
- K J Williams
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, 210 Food Safety and Toxicology Building, Michigan State University, East Lansing, MI 48824, USA.
| |
Collapse
|
12
|
Tulchinsky DA, Hastings AS, Williams KJ. Characteristics and performance of offset phase locked single frequency heterodyned laser systems. Rev Sci Instrum 2016; 87:053107. [PMID: 27250392 DOI: 10.1063/1.4946999] [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] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We demonstrate and characterize the performance of two heterodyned optical phase locked loop (PLL) laser systems for use in characterizing photodetector RF frequency response and nonlinearities. Descriptions of PLL circuit parameters for Nd:YAG non-planar ring oscillator lasers at 1064 nm and 1319 nm, and Er ion fiber lasers from 1530 nm to 1565 nm are presented. Both laser systems have piezoelectric transducer wavelength control over the PLL voltage controlled oscillator circuit. Offset frequency phase locking from 1.5 kHz to 51+ GHz is demonstrated. Frequency stability at 10 MHz is measured to be ±50 μHz, limited by the stability of the Rb stabilized crystal oscillator. Phase noise of the phase-locked 1319 nm laser system is discussed where we find that the phase noise is dominated by the input source noise at frequency offsets below 100 Hz and by the laser's RIN noise at frequency offsets > 100 Hz. Comparing nonlinearity data from an InGaAs p-i-n photodiode using both 1319 nm and 1550 nm PLL nonlinearity measurement systems, we find two new separate photodetector nonlinearity mechanisms. Measurements of the harmonic components of a 11 MHz sinusoidal heterodyned optical beat note signal are found to be at or below 1 nW/mW for the second harmonic (at 22 MHz) and at or below 0.25 nW/mW for the 3rd harmonic (at 33 MHz), confirming the nearly pure sinusoidal nature of the optically generated microwave beat note.
Collapse
|
13
|
Hu Y, Menyuk CR, Hutchinson MN, Urick VJ, Williams KJ. Impact of the Coulomb interaction on the Franz-Keldysh effect in high-current photodetectors. Opt Lett 2016; 41:456-459. [PMID: 26907396 DOI: 10.1364/ol.41.000456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The Franz-Keldysh effect has been recognized as the largest contributor to oscillations in the responsivity of high-current photodetectors as a function of the applied bias or the incident light wavelength and to device nonlinearity. Prior work only considered the effect of the electric field without considering the Coulomb interaction. We show that it is not possible to obtain agreement with experiments at all optical wavelengths without including this effect in the effective mass equation. We find the maxima and minima in the absorption of the applied electric field shift when the Coulomb interaction is included. We then use the calculated absorption with the drift-diffusion equations to calculate the responsivity in a partially depleted absorber (PDA) photodetector, and we obtain excellent agreement with experiments at all biases and optical wavelengths.
Collapse
|
14
|
Abstract
BACKGROUND Peripheral arterial disease (PAD) is common and symptoms can be debilitating and lethal. Risk management, exercise, radiological and surgical intervention are all valuable therapies, but morbidity and mortality rates from this disease are increasing. Circulatory enhancement can be achieved using simple medical electronic devices, with claims of minimal adverse side effects. The evidence for these is variable, prompting a review of the available literature. METHODS Embase and Medline were interrogated for full text articles in humans and written in English. Any external medical devices used in the management of peripheral arterial disease were included if they had objective outcome data. RESULTS Thirty-one papers met inclusion criteria, but protocols were heterogenous. The medical devices reported were intermittent pneumatic compression (IPC), electronic nerve (NMES) or muscle stimulators (EMS), and galvanic electrical dressings. In patients with intermittent claudication, IPC devices increase popliteal artery velocity (49-70 %) and flow (49-84 %). Gastrocnemius EMS increased superficial femoral artery flow by 140 %. Over 4.5-6 months IPC increased intermittent claudication distance (ICD) (97-150 %) and absolute walking distance (AWD) (84-112 %), with an associated increase in quality of life. NMES of the calf increased ICD and AWD by 82 % and 61-150 % at 4 weeks, and 26 % and 34 % at 8 weeks. In patients with critical limb ischaemia IPC reduced rest pain in 40-100 % and was associated with ulcer healing rates of 26 %. IPC had an early limb salvage rate of 58-83 % at 1-3 months, and 58-94 % at 1.5-3.5 years. No studies have reported the use of EMS or NMES in the management of CLI. CONCLUSION There is evidence to support the use of IPC in the management of claudication and CLI. There is a building body of literature to support the use of electrical stimulators in PAD, but this is low level to date. Devices may be of special benefit to those with limited exercise capacity, and in non-reconstructable critical limb ischaemia. Galvanic stimulation is not recommended.
Collapse
Affiliation(s)
- K J Williams
- Section of Surgery, Imperial College London, London, UK
| | - A Babber
- Section of Surgery, Imperial College London, London, UK
| | - R Ravikumar
- Section of Surgery, Imperial College London, London, UK
| | - A H Davies
- Section of Surgery, Imperial College London, London, UK. .,Charing Cross Hospital, 4th Floor, Fulham Palace Road, London, W6 8RF, UK.
| |
Collapse
|
15
|
O'Connor JPB, Boult JKR, Jamin Y, Babur M, Finegan KG, Williams KJ, Reynolds AR, Little RA, Jackson A, Parker GJM, Waterton JC, Robinson SP. Oxygen-enhanced MRI can accurately identify, quantify and map tumour hypoxia in preclinical models. Cancer Imaging 2015. [PMCID: PMC4601618 DOI: 10.1186/1470-7330-15-s1-p9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
16
|
Wou J, Williams KJ, Davies AH. Compression Stockings versus Neuromuscular Electrical Stimulation Devices in the Management of Occupational Leg Swelling. Int J Angiol 2015; 25:104-9. [PMID: 27231426 DOI: 10.1055/s-0035-1558646] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Background Occupational edema is reported to occur in healthy individuals after working in a sitting or standing position for extensive periods of time. It can be associated with feelings of tiredness, heaviness of the legs, and pain. Three licensed medical devices were compared in their management of occupational edema. Subjects and Methods A total of 10 subjects were recruited from a clinical workspace. Right leg volume and great saphenous vein diameter was measured in the morning, and 6 hours later. On subsequent separate days, grade 2 graduated compression stockings (Active Compression Socks, Mediven, United Kingdom), geko (Firstkind Ltd, United Kingdom), and Revitive (Actegy Ltd, United Kingdom) were used bilaterally according to manufacturer's instructions. Results Leg volumes increased by median 41 mL (p < 0.05) with no intervention. Percentage increase in leg volume was found to be significantly reduced by stockings compared with control (-1.7%, p < 0.01), and were more effective than electrical devices. Changes in vein diameter poorly correlate with leg volume changes. Conclusion Occupational edema can occur over as little as 6 hours. All devices were well tolerated and reduced leg swelling. Stockings were the only device to significantly reduce leg swelling in this small trial.
Collapse
Affiliation(s)
- J Wou
- Section of Surgery, Imperial College London, London, United Kingdom
| | - K J Williams
- Section of Surgery, Imperial College London, London, United Kingdom
| | - A H Davies
- Section of Surgery, Imperial College London, London, United Kingdom
| |
Collapse
|
17
|
Hu Y, Carruthers TF, Menyuk CR, Hutchinson MN, Urick VJ, Williams KJ. Simulation of a partially depleted absorber (PDA) photodetector. Opt Express 2015; 23:20402-20417. [PMID: 26367895 DOI: 10.1364/oe.23.020402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We use a 2D drift-diffusion model to study the nonlinear response of a partially depleted absorber (PDA) phododetector. The model includes external loading, incomplete ionization, the Franz-Keldysh effect, and history-dependent impact ionization. It also takes into account heat flow in the device. With all these effects included, we obtain excellent agreement with experiments for the responsivity and for the harmonic power at different modulation frequencies. The role of these different physical effects is elucidated, and we find that both the Franz-Keldysh effect and the load resistance play a key role in generating higher harmonic power at larger reverse biases. Increasing the size of the p-region absorption layers reduces the impact of the Franz-Keldysh effect. Decreasing the effective load resistance also decreases the higher harmonic powers. We also show that the model can suggest design changes that will improve device performance.
Collapse
|
18
|
Abstract
A longitudinal study was conducted to assess the methods available for detection of Escherichia coli O157 and to investigate the prevalence and occurrence of long-term shedding and super shedding in a cohort of Australian dairy heifers. Samples were obtained at approximately weekly intervals from heifers at pasture under normal management systems. Selective sampling techniques were used with the aim of identifying heifers with a higher probability of shedding or super shedding. Rectoanal mucosal swabs (RAMS) and fecal samples were obtained from each heifer. Direct culture of feces was used for detection and enumeration. Feces and RAMS were tested by enrichment culture. Selected samples were further tested retrospectively by immunomagnetic separation of enriched samples. Of 784 samples obtained, 154 (19.6%) were detected as positive using culture methods. Adjusting for selective sampling, the prevalence was 71 (15.6%) of 454. In total, 66 samples were detected as positive at >10(2) CFU/g of which 8 were >10(4) CFU/g and classed as super shedding. A significant difference was observed in detection by enriched culture of RAMS and feces. Dairy heifers within this cohort exhibited variable E. coli O157 shedding, consistent with previous estimates of shedding. Super shedding was detected at a low frequency and inconsistently from individual heifers. All detection methods identified some samples as positive that were not detected by any other method, indicating that the testing methods used will influence survey results.
Collapse
Affiliation(s)
- K J Williams
- Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden, New South Wales, 2570, Australia.
| | - M P Ward
- Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden, New South Wales, 2570, Australia
| | - O P Dhungyel
- Faculty of Veterinary Science, University of Sydney, 425 Werombi Road, Camden, New South Wales, 2570, Australia
| |
Collapse
|
19
|
Robinson NE, Williams KJ, Stack A, Jackson WF, Derksen FJ. Exercise-induced pulmonary haemorrhage: A progressive disease affecting performance? Equine Vet J 2015; 47:339-40. [PMID: 25712624 DOI: 10.1111/evj.12412] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- N E Robinson
- Large Animal Clinical Sciences, Michigan State University, East Lansing, USA
| | | | | | | | | |
Collapse
|
20
|
Fleming IN, Manavaki R, Blower PJ, West C, Williams KJ, Harris AL, Domarkas J, Lord S, Baldry C, Gilbert FJ. Imaging tumour hypoxia with positron emission tomography. Br J Cancer 2015; 112:238-50. [PMID: 25514380 PMCID: PMC4453462 DOI: 10.1038/bjc.2014.610] [Citation(s) in RCA: 188] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Revised: 09/30/2014] [Accepted: 11/10/2014] [Indexed: 01/02/2023] Open
Abstract
Hypoxia, a hallmark of most solid tumours, is a negative prognostic factor due to its association with an aggressive tumour phenotype and therapeutic resistance. Given its prominent role in oncology, accurate detection of hypoxia is important, as it impacts on prognosis and could influence treatment planning. A variety of approaches have been explored over the years for detecting and monitoring changes in hypoxia in tumours, including biological markers and noninvasive imaging techniques. Positron emission tomography (PET) is the preferred method for imaging tumour hypoxia due to its high specificity and sensitivity to probe physiological processes in vivo, as well as the ability to provide information about intracellular oxygenation levels. This review provides an overview of imaging hypoxia with PET, with an emphasis on the advantages and limitations of the currently available hypoxia radiotracers.
Collapse
Affiliation(s)
- I N Fleming
- Aberdeen Biomedical Imaging Centre, Lilian Sutton Building, Foresterhill, Aberdeen AB25 2ZD, UK
| | - R Manavaki
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218-Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
| | - P J Blower
- Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, King's College London, 4th Floor, Lambeth Wing, London SE1 7EH, UK
| | - C West
- Manchester Academic Health Science Centre, Institute of Cancer Sciences, University of Manchester, Wilmslow Road, Manchester M20 4BX, UK
| | - K J Williams
- Manchester Pharmacy School, Faculty of Medical and Human Sciences, University Manchester, Stopford Building, Oxford Road, Manchester M13 9PT, UK
- EPSRC and CRUK Cancer Imaging Centre in Cambridge and Manchester, Cambridge, UK
| | - A L Harris
- Molecular Oncology Laboratories, University Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
| | - J Domarkas
- Centre for Cardiovascular and Metabolic Research, Respiratory Medicine, Hull-York Medical School, University of Hull, Hull HU16 5JQ, UK
| | - S Lord
- Molecular Oncology Laboratories, University Department of Medical Oncology, The Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Headington, Oxford OX3 9DS, UK
| | - C Baldry
- Division of Imaging Sciences and Biomedical Engineering, St Thomas' Hospital, King's College London, 4th Floor, Lambeth Wing, London SE1 7EH, UK
| | - F J Gilbert
- Department of Radiology, School of Clinical Medicine, University of Cambridge, Box 218-Cambridge Biomedical Campus, Cambridge CB2 0QQ, UK
- EPSRC and CRUK Cancer Imaging Centre in Cambridge and Manchester, Cambridge, UK
| |
Collapse
|
21
|
Joshi N, Kopec AK, O'Brien KM, Towery KL, Cline-Fedewa H, Williams KJ, Copple BL, Flick MJ, Luyendyk JP. Coagulation-driven platelet activation reduces cholestatic liver injury and fibrosis in mice. J Thromb Haemost 2015; 13:57-71. [PMID: 25353084 PMCID: PMC4487795 DOI: 10.1111/jth.12770] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [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] [Received: 03/18/2014] [Accepted: 10/17/2014] [Indexed: 01/14/2023]
Abstract
BACKGROUND The coagulation cascade has been shown to participate in chronic liver injury and fibrosis, but the contribution of various thrombin targets, such as protease activated receptors (PARs) and fibrin(ogen), has not been fully described. Emerging evidence suggests that in some experimental settings of chronic liver injury, platelets can promote liver repair and inhibit liver fibrosis. However, the precise mechanisms linking coagulation and platelet function to hepatic tissue changes following injury remain poorly defined. OBJECTIVES To determine the role of PAR-4, a key thrombin receptor on mouse platelets, and fibrin(ogen) engagement of the platelet αII b β3 integrin (αIIb β3 ) in a model of cholestatic liver injury and fibrosis. METHODS Biliary and hepatic injury was characterized following 4 week administration of the bile duct toxicant α-naphthylisothiocyanate (ANIT) (0.025%) in PAR-4-deficient mice, mice expressing a mutant form of fibrin(ogen) incapable of binding integrin αII b β3 (Fibγ(Δ5) ), and wild-type mice. RESULTS Elevated plasma thrombin-antithrombin and serotonin levels, hepatic fibrin deposition, and platelet accumulation in liver accompanied hepatocellular injury and fibrosis in ANIT-treated wild-type mice. PAR-4 deficiency reduced plasma serotonin levels, increased serum bile acid concentration, and exacerbated ANIT-induced hepatocellular injury and peribiliary fibrosis. Compared with PAR-4-deficient mice, ANIT-treated Fibγ(Δ5) mice displayed more widespread hepatocellular necrosis accompanied by marked inflammation, robust fibroblast activation, and extensive liver fibrosis. CONCLUSIONS Collectively, the results indicate that PAR-4 and fibrin-αII b β3 integrin engagement, pathways coupling coagulation to platelet activation, each exert hepatoprotective effects during chronic cholestasis.
Collapse
MESH Headings
- 1-Naphthylisothiocyanate
- Animals
- Antithrombin III
- Bile Acids and Salts/blood
- Blood Coagulation/genetics
- Blood Platelets/metabolism
- Chemical and Drug Induced Liver Injury/blood
- Chemical and Drug Induced Liver Injury/genetics
- Chemical and Drug Induced Liver Injury/pathology
- Chemical and Drug Induced Liver Injury/prevention & control
- Cholestasis/blood
- Cholestasis/chemically induced
- Cholestasis/genetics
- Cholestasis/pathology
- Cholestasis/prevention & control
- Fibrinogens, Abnormal/genetics
- Fibrinogens, Abnormal/metabolism
- Genotype
- Liver/metabolism
- Liver/pathology
- Liver Cirrhosis, Experimental/blood
- Liver Cirrhosis, Experimental/chemically induced
- Liver Cirrhosis, Experimental/genetics
- Liver Cirrhosis, Experimental/pathology
- Liver Cirrhosis, Experimental/prevention & control
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Mutation
- Necrosis
- Peptide Hydrolases/blood
- Phenotype
- Platelet Activation/genetics
- Platelet Glycoprotein GPIIb-IIIa Complex/metabolism
- Receptors, Thrombin/deficiency
- Receptors, Thrombin/genetics
- Serotonin/blood
- Signal Transduction
Collapse
Affiliation(s)
- N Joshi
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, MI, USA; Center for Integrative Toxicology, Michigan State University, East Lansing, MI, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
22
|
|
23
|
Bryant JL, Meredith SL, Williams KJ, White A. Targeting hypoxia in the treatment of small cell lung cancer. Lung Cancer 2014; 86:126-32. [PMID: 25201720 DOI: 10.1016/j.lungcan.2014.08.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 12/17/2022]
Abstract
Small cell lung cancer (SCLC) is an extremely aggressive disease for which minimal therapeutic improvements have been made over the last few decades. Patients still rely on non-targeted, chemotherapeutic drugs complemented by irradiation. Although initial response is very good, the majority of SCLC patients invariably relapse with therapy-resistant tumours. Despite the link between pathologically low oxygen levels and therapy resistant tumours, hypoxia has gained little attention in the development of novel therapies for SCLC. In contrast, the advantages of targeting hypoxic cells in many other cancer types have been studied extensively. This review describes the reasons for targeting hypoxia in SCLC and outlines strategies undertaken to enhance hypoxic tumour cell death, including the use of bioreductive prodrugs, the targeting of HIF-1α and the induction of cell death through acidosis. Therapy directed towards hypoxic tumour regions has the potential to greatly enhance the response of SCLC tumours to current treatment regimens and represents an area of research in need of greater attention. Such research could lead to the much sought after development of targeted drugs against SCLC tumours.
Collapse
Affiliation(s)
- J L Bryant
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK; Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK
| | - S L Meredith
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK
| | - K J Williams
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK
| | - A White
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK; Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, AV Hill Building, Manchester M13 9PT, UK.
| |
Collapse
|
24
|
Williams KJ, Ward MP, Dhungyel O, Van Breda L. Relative sensitivity of Escherichia coli O157 detection from bovine feces and rectoanal mucosal swabs. J Food Prot 2014; 77:972-6. [PMID: 24853520 DOI: 10.4315/0362-028x.jfp-13-500] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The need to quantify the potential human health risk posed by the bovine reservoir of Escherichia coli O157 has led to a wealth of prevalence studies and improvements in detection methods over the last two decades. Rectoanal mucosal swabs have been used for the detection of E. coli O157 fecal shedding, colonized animals, and those predisposed to super shedding. We conducted a longitudinal study to compare the detection of E. coli O157 from feces and rectoanal mucosal swabs (RAMS) from a cohort of dairy heifers. We collected 820 samples that were tested by immunomagnetic separation of both feces and RAMS. Of these, 132 were detected as positive for E. coli O157 from both samples, 66 were detected as positive from RAMS only, and 117 were detected as positive from feces only. The difference in results between the two sample types was statistically significant (P < 0.001). The relative sensitivities of detection by immunomagnetic separation were 53% (confidence interval, 46.6 to 59.3) from RAMS and 67% (confidence interval, 59.6 to 73.1) from fecal samples. No association between long-term shedding (P = 0.685) or super shedding (P = 0.526) and detection by RAMS only was observed.
Collapse
Affiliation(s)
- K J Williams
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales 2570, Australia.
| | - M P Ward
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales 2570, Australia
| | - O Dhungyel
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales 2570, Australia
| | - L Van Breda
- Faculty of Veterinary Science, University of Sydney, Camden, New South Wales 2570, Australia
| |
Collapse
|
25
|
Hammond EM, Asselin MC, Forster D, O'Connor JPB, Senra JM, Williams KJ. The meaning, measurement and modification of hypoxia in the laboratory and the clinic. Clin Oncol (R Coll Radiol) 2014; 26:277-88. [PMID: 24602562 DOI: 10.1016/j.clon.2014.02.002] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [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] [Received: 12/06/2013] [Revised: 01/23/2014] [Accepted: 02/04/2014] [Indexed: 01/12/2023]
Abstract
Hypoxia was identified as a microenvironmental component of solid tumours over 60 years ago and was immediately recognised as a potential barrier to therapy through the reliance of radiotherapy on oxygen to elicit maximal cytotoxicity. Over the last two decades both clinical and experimental studies have markedly enhanced our understanding of how hypoxia influences cellular behaviour and therapy response. Furthermore, they have confirmed early assumptions that low oxygenation status in tumours is an exploitable target in cancer therapy. Generally such approaches will be more beneficial to patients with hypoxic tumours, necessitating the use of biomarkers that reflect oxygenation status. Tissue biomarkers have shown utility in many studies. Further significant advances have been made in the non-invasive measurement of tumour hypoxia with positron emission tomography, magnetic resonance imaging and other imaging modalities. Here, we describe the complexities of defining and measuring tumour hypoxia and highlight the therapeutic approaches to combat it.
Collapse
Affiliation(s)
- E M Hammond
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, UK
| | - M-C Asselin
- Wolfson Molecular Imaging Centre, Manchester, UK
| | - D Forster
- Wolfson Molecular Imaging Centre, Manchester, UK
| | - J P B O'Connor
- Centre for Imaging Sciences, Institute of Population Health, Manchester, UK
| | - J M Senra
- The Gray Institute for Radiation Oncology and Biology, Department of Oncology, University of Oxford, Oxford, UK
| | - K J Williams
- Manchester Pharmacy School, Cambridge-Manchester Cancer Research UK Comprehensive Imaging Centre, Manchester Academic Health Sciences Centre, The University Manchester, Manchester, UK.
| |
Collapse
|
26
|
Williams KJ, Moore HM, Davies AH. Haemodynamic changes with the use of neuromuscular electrical stimulation compared to intermittent pneumatic compression. Phlebology 2014; 30:365-72. [PMID: 24722790 DOI: 10.1177/0268355514531255] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Enhancement of peripheral circulation has been shown to be of benefit in many vascular disorders, and the clinical effectiveness of intermittent pneumatic compression is well established in peripheral vascular disease. This study compares the haemodynamic efficacy of a novel neuromuscular electrical stimulation device with intermittent pneumatic compression in healthy subjects. METHODS Ten healthy volunteers (mean age 27.1 ± 3.8 years, body mass index 24.8 ± 3.6 kg/m(2)) were randomised into two groups, in an interventional crossover trial. Devices used were the SCD Express™ Compression System, (Covidien, Ireland) and the geko™, (Firstkind Ltd, UK). Devices were applied bilaterally, and haemodynamic measurements taken from the left leg. Changes to haemodynamic parameters (superficial femory artery and femoral vein) and laser Doppler measurements from the hand and foot were compared. RESULTS Intermittent pneumatic compression caused 51% (p = 0.002), 5% (ns) and 3% (ns) median increases in venous peak velocity, time-averaged maximum velocity and volume flow, respectively; neuromuscular electrical stimulator stimulation caused a 103%, 101% and 101% median increases in the same parameters (all p = 0.002). The benefit was lost upon deactivation. Intermittent pneumatic compression did not improve arterial haemodynamics. Neuromuscular electrical stimulator caused 11%, 84% and 75% increase in arterial parameters (p < 0.01). Laser Doppler readings taken from the leg were increased by neuromuscular electrical stimulator (p < 0.001), dropping after deactivation. For intermittent pneumatic compression, the readings decreased during use but increased after cessation. Hand flux signal dropped during activation of both devices, rising after cessation. DISCUSSION The neuromuscular electrical stimulator device used in this study enhances venous flow and peak velocity in the legs of healthy subjects and is equal or superior to intermittent pneumatic compression. This warrants further clinical and economic evaluation for deep venous thrombosis prophylaxis and exploration of the haemodynamic effect in venous pathology. It also enhances arterial time-averaged maximum velocity and flow rate, which may prove to be of clinical use in the management of peripheral arterial disease. The effect on the microcirculation as evidenced by laser Doppler fluximetry may reflect a clinically beneficial target in microvascular disease, such as in the diabetic foot.
Collapse
Affiliation(s)
- K J Williams
- Academic Section of Vascular Surgery, Imperial College London, London, UK
| | - H M Moore
- Academic Section of Vascular Surgery, Imperial College London, London, UK
| | - A H Davies
- Academic Section of Vascular Surgery, Imperial College London, London, UK
| |
Collapse
|
27
|
Hutchinson MN, Harmon SR, Urick VJ, Williams KJ. Analysis of magnitude and relative phase of photodiode IMD2 using amplitude matched MZM-distortion cancellation technique. Opt Express 2014; 22:962-971. [PMID: 24515056 DOI: 10.1364/oe.22.000962] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We present a detailed look at using Mach-Zehnder modulator generated distortion for identifying the magnitude and relative sign of photodiode generated second order intermodulation distortion (IMD2). Previous discussions introduced the concept for characterizing a test device. Analysis is expanded to IMD2 as a function of voltage, photocurrent and frequency.
Collapse
|
28
|
Williams KJ, Hayes AJ. A guide to oncological management of soft tissue tumours of the abdominal wall. Hernia 2013; 18:91-7. [PMID: 24043554 DOI: 10.1007/s10029-013-1156-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 09/06/2013] [Indexed: 02/02/2023]
Abstract
INTRODUCTION An abdominal mass is a common clinical presentation, and a small percentage of such patients will have an abdominal wall tumour with the two most common pathologies being fibromatosis and soft tissue sarcoma. METHODS Here we present the available literature on the diagnosis and management of both fibromatosis and soft tissue sarcoma, in the context of our experience in a tertiary referral centre for sarcoma. RESULTS AND DISCUSSION Appropriate cross-sectional imaging and a pre-operative tissue diagnosis by percutaneous core biopsy are necessary to define management. Desmoid fibromatosis can be managed initially by observation with serial imaging, with surgery being reserved for those patients who demonstrate progression. Soft tissue sarcoma can display a range of pathologies from relatively indolent tumours to locally aggressive sarcomas that can readily metastasise. An accurate pre-operative histological diagnosis and staging enables a multidisciplinary approach to management. This may include chemotherapy and radiotherapy, but the mainstay of treatment remains wide surgical resection and abdominal wall reconstruction. Patient outcomes are worse if referral is delayed or if the sarcoma is incompletely resected without an initial tissue diagnosis.
Collapse
Affiliation(s)
- K J Williams
- Academic Section of Vascular Surgery, Imperial College London, London, UK,
| | | |
Collapse
|
29
|
Urick VJ, Hutchinson MN, Singley JM, McKinney JD, Williams KJ. Suppression of even-order photodiode distortions via predistortion linearization with a bias-shifted Mach-Zehnder modulator. Opt Express 2013; 21:14368-14376. [PMID: 23787625 DOI: 10.1364/oe.21.014368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A new technique to cancel photodiode-induced even-order distortion in microwave photonic links is demonstrated. A single Mach-Zehnder modulator, biased slightly away from the quadrature point, is shown to suppress photodiode second-order intermodulation distortion in excess of 40 dB without affecting the fundamental power. The technique is theoretically described with supporting experimental results.
Collapse
Affiliation(s)
- Vincent J Urick
- Optical Sciences Division, Naval Research Laboratory, 4555 Overlook Avenue SW, Washington, DC 20375, USA.
| | | | | | | | | |
Collapse
|
30
|
Abstract
Lymphatic malformations are a subset of congenital vascular malformations, and are caused by a defect in lymphatic development during embryogenesis. When lymphatic mesoderm development is prematurely arrested, it retains it proliferative potential. Stimulus in the future can cause the lesion to proliferate locally without coordination or regulation, resulting in the rare condition known as massive localised lymphoedema (MLL). We present a case report of MLL, a rare and ill-defined soft tissue mass reported in the morbidly obese, with reference to the existing literature.
Collapse
Affiliation(s)
- K J Williams
- Academic Section of Vascular Surgery, Imperial College London, London, UK.
| | | | | | | |
Collapse
|
31
|
Simpson KL, Cawthorne C, Zhou C, Hodgkinson CL, Walker MJ, Trapani F, Kadirvel M, Brown G, Dawson MJ, MacFarlane M, Williams KJ, Whetton AD, Dive C. A caspase-3 'death-switch' in colorectal cancer cells for induced and synchronous tumor apoptosis in vitro and in vivo facilitates the development of minimally invasive cell death biomarkers. Cell Death Dis 2013; 4:e613. [PMID: 23640455 PMCID: PMC3674346 DOI: 10.1038/cddis.2013.137] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/22/2013] [Accepted: 02/25/2013] [Indexed: 12/19/2022]
Abstract
Novel anticancer drugs targeting key apoptosis regulators have been developed and are undergoing clinical trials. Pharmacodynamic biomarkers to define the optimum dose of drug that provokes tumor apoptosis are in demand; acquisition of longitudinal tumor biopsies is a significant challenge and minimally invasive biomarkers are required. Considering this, we have developed and validated a preclinical 'death-switch' model for the discovery of secreted biomarkers of tumour apoptosis using in vitro proteomics and in vivo evaluation of the novel imaging probe [(18)F]ML-10 for non-invasive detection of apoptosis using positron emission tomography (PET). The 'death-switch' is a constitutively active mutant caspase-3 that is robustly induced by doxycycline to drive synchronous apoptosis in human colorectal cancer cells in vitro or grown as tumor xenografts. Death-switch induction caused caspase-dependent apoptosis between 3 and 24 hours in vitro and regression of 'death-switched' xenografts occurred within 24 h correlating with the percentage of apoptotic cells in tumor and levels of an established cell death biomarker (cleaved cytokeratin-18) in the blood. We sought to define secreted biomarkers of tumor apoptosis from cultured cells using Discovery Isobaric Tag proteomics, which may provide candidates to validate in blood. Early after caspase-3 activation, levels of normally secreted proteins were decreased (e.g. Gelsolin and Midkine) and proteins including CD44 and High Mobility Group protein B1 (HMGB1) that were released into cell culture media in vitro were also identified in the bloodstream of mice bearing death-switched tumors. We also exemplify the utility of the death-switch model for the validation of apoptotic imaging probes using [(18)F]ML-10, a PET tracer currently in clinical trials. Results showed increased tracer uptake of [(18)F]ML-10 in tumours undergoing apoptosis, compared with matched tumour controls imaged in the same animal. Overall, the death-switch model represents a robust and versatile tool for the discovery and validation of apoptosis biomarkers.
Collapse
Affiliation(s)
- K L Simpson
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| | - C Cawthorne
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, UK
| | - C Zhou
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| | - C L Hodgkinson
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| | - M J Walker
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
- Stem Cell and Leukaemia Proteomics Laboratory, School of Cancer and Enabling Sciences, University of Manchester, Manchester Academic Health Science Centre, Christie Hospital, Manchester, UK
| | - F Trapani
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| | - M Kadirvel
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, UK
| | - G Brown
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, UK
| | - M J Dawson
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| | - M MacFarlane
- MRC Toxicology Unit, Hodgkin Building, University of Leicester, Lancaster Road, Leicester, UK
| | - K J Williams
- Wolfson Molecular Imaging Centre, University of Manchester, 27 Palatine Road, Manchester, UK
| | - A D Whetton
- Stem Cell and Leukaemia Proteomics Laboratory, School of Cancer and Enabling Sciences, University of Manchester, Manchester Academic Health Science Centre, Christie Hospital, Manchester, UK
| | - C Dive
- Clinical and Experimental Pharmacology Group, Paterson Institute for Cancer Research, University of Manchester and Manchester Cancer Research Centre, Wilmslow Road, Withington, Manchester, UK
| |
Collapse
|
32
|
Stovold R, Meredith SL, Bryant JL, Babur M, Williams KJ, Dean EJ, Dive C, Blackhall FH, White A. Neuroendocrine and epithelial phenotypes in small-cell lung cancer: implications for metastasis and survival in patients. Br J Cancer 2013; 108:1704-11. [PMID: 23519056 PMCID: PMC3668479 DOI: 10.1038/bjc.2013.112] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 02/12/2013] [Accepted: 02/20/2013] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND Small-cell lung cancer (SCLC) has a very aggressive clinical course with early metastasis. This study investigated how the distinctive neuroendocrine characteristics contribute to disease progression and invasion in human SCLC. METHODS The neuroendocrine phenotype (pro-opiomelanocortin (POMC)) was quantified by ELISA in blood samples from 43 SCLC patients. The neuroendocrine (POMC, chromogranin A, neuron-specific enolase, NCAM) and epithelial (cytokeratin and E-cadherin) phenotypes were investigated, using ELISA and immunocytochemistry/immunohistochemistry. RESULTS In SCLC patients, 16% had elevated circulating POMC, which was associated with significantly worse survival (P=0.02) and liver metastases (P=0.004). In addition, POMC correlated with epithelial-positive circulating tumour cells (P=0.0002). In a panel of SCLC cell lines, all POMC-secreting cell lines expressed cytokeratin (40% of total). Even after cloning, DMS 79 cells expressed both neuroendocrine and epithelial markers. DMS 79 xenografts secreted POMC into the blood, which mirrored the tumour volume. These xenografts expressed both neuroendocrine and epithelial phenotypes in all tumours, with both phenotypes prevalent in cells invading the surrounding tissue. CONCLUSION Both neuroendocrine and epithelial phenotypes coexist in human SCLC tumours in vitro and in vivo and this persists in invading tumour cells. In patients, POMC secretion predicts poor survival and liver metastases, suggesting a crucial role of the neuroendocrine phenotype.
Collapse
Affiliation(s)
- R Stovold
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, 3.016 AV Hill Building, Manchester M13 9PT, UK
- Paterson Institute for Cancer Research, University of Manchester, Manchester M20 4BX, UK
| | - S L Meredith
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, 3.016 AV Hill Building, Manchester M13 9PT, UK
| | - J L Bryant
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, 3.016 AV Hill Building, Manchester M13 9PT, UK
| | - M Babur
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Stopford Building, Manchester M13 9PT, UK
| | - K J Williams
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Stopford Building, Manchester M13 9PT, UK
| | - E J Dean
- Paterson Institute for Cancer Research, University of Manchester, Manchester M20 4BX, UK
| | - C Dive
- Paterson Institute for Cancer Research, University of Manchester, Manchester M20 4BX, UK
| | - F H Blackhall
- The Christie NHS Foundation Trust, Manchester M20 4BX, UK
| | - A White
- Faculty of Life Sciences, Manchester Academic Health Sciences Centre, University of Manchester, 3.016 AV Hill Building, Manchester M13 9PT, UK
- Faculty of Medical and Human Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Stopford Building, Manchester M13 9PT, UK
| |
Collapse
|
33
|
Abstract
Photodiode nonlinearity measurements using one-, two- and three-tone measurement systems are compared with each other, to investigate the comparison accuracy between setups. The mathematical relationship between each setup is analyzed, and data on multiple devices are compared to find under which conditions the measurements are comparable. It is shown that the three measurement systems can be used interchangeably only when the distortion adheres to the expected mathematical slopes.
Collapse
Affiliation(s)
- Meredith N Draa
- Global Defense Technology & Systems, Inc., 2200 Defense Highway, Suite 405, Crofton, MD 21114, USA.
| | | | | |
Collapse
|
34
|
Williams KJ, Derksen FJ, Defeijter-Rupp HL, Robinson NE. Repeated blood instillation into the airway of the horse does not cause pulmonary fibrosis. Equine Vet J 2011; 43:354-8. [PMID: 21492214 DOI: 10.1111/j.2042-3306.2010.00163.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
REASONS FOR PERFORMING THE STUDY Exercise-induced pulmonary haemorrhage (EIPH) occurs in nearly all strenuously exercising horses. Recent studies have attempted to identify the role of free blood within the airspaces, in the lung fibrosis that develops within the lungs of EIPH horses. HYPOTHESIS Repeated exposure of the equine lung to autologous blood results in lung fibrosis similar to that observed in spontaneous EIPH. METHODS Forty ml of autologous blood from the jugular vein was instilled into preselected lung regions of 6 horses one, 2, 3, 4 or 5 times at 2 week intervals, with 40 ml of saline instilled into the contralateral lung serving as a control. The time interval between instillation of the first blood and euthanasia ranged from 2-10 weeks. The lung from each instillation site was harvested, and the histopathology was scored from each region based upon the presence and abundance of blood, haemosiderin and interstitial collagen. Consequently, at the time of euthanasia, the time since instillation of the first blood ranged from 2-10 weeks. RESULTS Beyond retention of blood, and the accumulation of haemosiderin, there was no visible increase in perivascular and interstitial collagen within the blood-instilled lung sites. In a small number of regions, there were foci of bronchiolitis obliterans organising pneumonia with collagen accumulation within these foci, but no collagen accumulation with the characteristic perivascular and interstitial histological distribution seen in EIPH. CONCLUSIONS Free blood within the airways of horses does not result in a qualitative increase in the amount of interstitial collagen within 8-10 weeks, and is therefore an unlikely aetiological factor in the lung collagen accumulation that occurs in EIPH. POTENTIAL RELEVANCE This study emphasises the efficiency of the equine lung in clearing blood from the airspaces. Further, it suggests that the aetiopathogenesis of EIPH is not driven by events within the airspace lumen, but rather emanates from within the vasculature and lung interstitium.
Collapse
Affiliation(s)
- K J Williams
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, USA.
| | | | | | | |
Collapse
|
35
|
Abstract
Hypoxia-inducible factor 1 alpha (HIF-1 alpha) is upregulated by hypoxia and oncogenic signalling in many solid tumours. Its regulation and function in thyroid carcinomas are unknown. We evaluated the regulation of HIF-1 alpha and target gene expression in primary thyroid carcinomas and thyroid carcinoma cell lines (BcPAP, WRO, FTC-133 and 8505c). HIF-1 alpha was not detectable in normal tissue but was expressed in thyroid carcinomas. Dedifferentiated anaplastic tumours (ATCs) exhibited high levels of nuclear HIF-1 alpha staining. The HIF-1 target glucose transporter 1 was expressed to a similar level in all tumour types, whereas carbonic anhydrase-9 was significantly elevated in ATCs. In vitro studies revealed a functionally active HIF-1 alpha pathway in thyroid cells with transcriptional activation observed after graded hypoxia (1% O(2), anoxia) or treatment with a hypoxia mimetic cobalt chloride. High basal and hypoxia-induced expression of HIF-1 alpha in FTC-133 cells that harbour a phosphatase and tensin homologue (PTEN) mutation was reduced by introduction of wild-type PTEN. Similarly, pharmacological inhibition of the phosphoinositide 3-kinase (PI3K) pathway using LY294002 inhibited HIF-1 alpha and HIF-1 alpha targets in all cell lines, including those with B-RAF mutations (BcPAP and 8505c). In contrast, the effects of inhibition of the RAF/MEK/extracellular signal-regulated kinase pathway were restricted by environmental condition and B-RAF mutation status. HIF-1 is functionally expressed in thyroid carcinomas and is regulated not only by hypoxia but also via growth factor signalling pathways and, in particular, the PI3K pathway. Given the strong association of HIF-1 alpha with an aggressive disease phenotype and therapeutic resistance, this pathway may be an attractive target for improved therapy in thyroid carcinomas.
Collapse
MESH Headings
- Adenocarcinoma, Follicular/genetics
- Adenocarcinoma, Follicular/metabolism
- Adenocarcinoma, Follicular/pathology
- Anaerobiosis
- Antigens, Neoplasm/biosynthesis
- Antigens, Neoplasm/genetics
- Carbonic Anhydrase IX
- Carbonic Anhydrases/biosynthesis
- Carbonic Anhydrases/genetics
- Carcinoma/genetics
- Carcinoma/metabolism
- Carcinoma/pathology
- Carcinoma, Papillary/genetics
- Carcinoma, Papillary/metabolism
- Carcinoma, Papillary/pathology
- Cell Hypoxia/physiology
- Cell Line, Tumor/drug effects
- Cell Line, Tumor/metabolism
- Chromones/pharmacology
- Cobalt/pharmacology
- Gene Expression Regulation, Neoplastic/drug effects
- Glucose Transporter Type 1/biosynthesis
- Glucose Transporter Type 1/genetics
- Humans
- Hypoxia-Inducible Factor 1, alpha Subunit/biosynthesis
- Hypoxia-Inducible Factor 1, alpha Subunit/genetics
- Hypoxia-Inducible Factor 1, alpha Subunit/physiology
- Morpholines/pharmacology
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/biosynthesis
- Neoplasm Proteins/genetics
- Neoplasm Proteins/physiology
- PTEN Phosphohydrolase/genetics
- PTEN Phosphohydrolase/physiology
- Phosphatidylinositol 3-Kinases/physiology
- Phosphoinositide-3 Kinase Inhibitors
- Proto-Oncogene Proteins B-raf/genetics
- RNA Interference
- RNA, Small Interfering/pharmacology
- Signal Transduction/physiology
- Thyroid Neoplasms/genetics
- Thyroid Neoplasms/metabolism
- Thyroid Neoplasms/pathology
Collapse
Affiliation(s)
- N Burrows
- School of Pharmacy and Pharmaceutical Sciences, University of ManchesterWilmslow Road, Manchester, M20 4BXUK
| | - J Resch
- Department of EndocrinologyChristie Hospital, University of ManchesterWilmslow Road, Manchester, M20 4BXUK
| | - R L Cowen
- School of Pharmacy and Pharmaceutical Sciences, University of ManchesterWilmslow Road, Manchester, M20 4BXUK
| | - R von Wasielewski
- Department of PathologyMedizinische Hochschule Hannover, FRGHannoverGermany
| | - C Hoang-Vu
- Experimental and Surgical OncologyUniversity of Halle-Wittenberg, FRGHalleGermany
| | - C M West
- Academic Department of Radiation OncologyUniversity of ManchesterManchesterUK
| | - K J Williams
- School of Pharmacy and Pharmaceutical Sciences, University of ManchesterWilmslow Road, Manchester, M20 4BXUK
| | - G Brabant
- Department of EndocrinologyChristie Hospital, University of ManchesterWilmslow Road, Manchester, M20 4BXUK
- (Correspondence should be addressed to G Brabant; )
| |
Collapse
|
36
|
Ramaswamy A, Nunoya N, Williams KJ, Klamkin J, Piels M, Johansson LA, Hastings A, Coldren LA, Bowers JE. Measurement of intermodulation distortion in high-linearity photodiodes. Opt Express 2010; 18:2317-2324. [PMID: 20174061 DOI: 10.1364/oe.18.002317] [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] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Accurately characterizing third order intermodulation distortion (IMD3) in high-linearity photodiodes is challenging. Two measurement techniques are evaluated-a standard two-tone measurement and a more complicated three-tone measurement technique to measure IMD3. A model of the measurement system is developed and used to analyze the limitations of the two techniques in determining the distortion of highly linear photodiodes. Experimental validation is provided by comparing the simulation trends with IMD3 results measured on two types of waveguide photodiodes: 1) an InP based uni-traveling-carrier (UTC) photodiode and 2) a Ge n-i-p waveguide photodetector on Silicon-on-Insulator (SOI) substrate.
Collapse
Affiliation(s)
- Anand Ramaswamy
- Department of Electrical & Computer Engineering, University of California Santa Barbara, Santa Barbara, CA 93106, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Sneddon SF, Telfer BA, Williams KJ, Bishop PN, Stratford IJ, Cowen RL. Opticin: a potent anti-angiogenic/antiproliferative agent for breast cancer therapy. Breast Cancer Res 2010; 12. [PMCID: PMC2875615 DOI: 10.1186/bcr2550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
38
|
Schermer RT, Bucholtz F, Villarruel CA, Gil Gil J, Andreadis TD, Williams KJ. Investigation of electrooptic modulator disruption by microwave-induced transients. Opt Express 2009; 17:22586-22602. [PMID: 20052184 DOI: 10.1364/oe.17.022586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
This paper presents a detailed investigation of the physical mechanisms underlying the disruption of a lithium niobate electrooptic modulator by RF pulses. It is shown that short-term modulator disruption is a direct consequence of resistive heating within the metal conductor of the coplanar waveguide electrode, which leads to a thermo-optic optical phase shift in the waveguides of the modulator. Resistive heating is also shown to contribute to permanent modulator damage at higher RF power. These results indicate that short-term RF disruption, and possibly RF damage, can be mitigated through improved thermal management. They also predict that short-term photonic link disruption can be reduced, if not eliminated, by use of a phase modulated photonic link.
Collapse
Affiliation(s)
- Ross T Schermer
- U.S. Naval Research Laboratory, 4555 Overlook Avenue, SW, Washington, D.C. 20375, USA
| | | | | | | | | | | |
Collapse
|
39
|
Derksen FJ, Williams KJ, Pannirselvam RR, de Feijter-Rupp H, Steel CM, Robinson NE. Regional distribution of collagen and haemosiderin in the lungs of horses with exercise-induced pulmonary haemorrhage. Equine Vet J 2009; 41:586-91. [PMID: 19803055 DOI: 10.2746/042516409x429419] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [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: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Regional veno-occlusive remodelling of pulmonary veins in EIPH-affected horses, suggests that pulmonary veins may be central to pathogenesis. The current study quantified site-specific changes in vein walls, collagen and haemosiderin accumulation, and pleural vascular profiles in the lungs of horses suffering EIPH. HYPOTHESIS In the caudodorsal lung regions of EIPH-affected horses, there is veno-occlusive remodelling with haemosiderosis, angiogenesis and fibrosis of the interstitium, interlobular septa and pleura. METHODS Morphometric methods were used to analyse the distribution and accumulation of pulmonary collagen and haemosiderin, and to count pleural vascular profiles in the lungs of 5 EIPH-affected and 2 control horses. RESULTS Vein wall thickness was greatest in the dorsocaudal lung and significantly correlated with haemosiderin accumulation. Increased venous, interstitial, pleural and septal collagen; lung haemosiderin; and pleural vascular profiles occurred together and changes were most pronounced in the dorsocaudal lung. Further, haemosiderin accumulation colocalised with decreased pulmonary vein lumen size. Vein wall thickening, haemosiderin accumulation and histological score were highly correlated and these changes occurred only in the caudodorsal part of the lung. CONCLUSION The colocalisation of these changes suggests that regional (caudodorsal) venous remodelling plays an important role in the pathogenesis of EIPH. POTENTIAL RELEVANCE The results support the hypothesis that repeated bouts of venous hypertension during strenuous exercise cause regional vein wall remodelling and collagen accumulation, venous occlusion and pulmonary capillary hypertension. Subjected to these high pressures, there is capillary stress failure, bleeding, haemosiderin accumulation and, subsequently, lung fibrosis.
Collapse
Affiliation(s)
- F J Derksen
- Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan 48824, USA
| | | | | | | | | | | |
Collapse
|
40
|
|
41
|
Roberts DL, Williams KJ, Cowen RL, Barathova M, Eustace AJ, Brittain-Dissont S, Tilby MJ, Pearson DG, Ottley CJ, Stratford IJ, Dive C. Contribution of HIF-1 and drug penetrance to oxaliplatin resistance in hypoxic colorectal cancer cells. Br J Cancer 2009; 101:1290-7. [PMID: 19755992 PMCID: PMC2768443 DOI: 10.1038/sj.bjc.6605311] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Hypoxia is as an indicator of poor treatment outcome. Consistently, hypoxic HCT116 colorectal cancer cells are resistant to oxaliplatin, although the mechanistic basis is unclear. This study sought to investigate the relative contribution of HIF-1 (hypoxia-inducible factor-1)-mediated gene expression and drug penetrance to oxaliplatin resistance using three-dimensional spheroids. METHODS Hypoxia-inducible factor-1alpha function was suppressed by the stable expression of a dominant-negative form in HCT116 cells (DN). Cells were drug exposed as monolayer or multicellular spheroid cultures. Cells residing at differing oxygenation status were isolated from Hoechst 33342-treated spheroids using flow cytometry. Sub-populations were subjected to clonogenic survival assays and to Inductively-Coupled Plasma Mass Spectroscopy to determine oxaliplatin uptake. RESULTS In spheroids, a sensitivity gradient (hypoxic<aerobic) was revealed by survival assays and this correlated with levels of platinum-bound DNA. The resistance of hypoxic sub-populations exceeded relative changes in adduct levels, implicating factors other than drug penetrance in cell response. Dominant-negative monolayer cells showed no resistance to oxaliplatin in hypoxia and spheroids; the relative resistance of hypoxic compared with aerobic sub-populations was reduced compared with those from controls. CONCLUSION Overall, data show that drug penetration, DNA damage levels and HIF-1-dependent processes, all contribute to the resistance of hypoxic cells to oxaliplatin.
Collapse
Affiliation(s)
- D L Roberts
- Paterson Institute for Cancer Research, University of Manchester, Manchester, UK
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Williams KJ. The changing face of febrile neutropenia-from monotherapy to moulds to mucositis. Why monotherapy? J Antimicrob Chemother 2009; 63 Suppl 1:i18-20. [PMID: 19372175 DOI: 10.1093/jac/dkp077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [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] Open
Abstract
This is an account of the history of the early days of monotherapy of infections in neutropenic patients with haematological malignancies. A chance encounter with Ben de Pauw led to his introduction to clinical drug development research, introduced him to Peter Donnelly who was studying ceftazidime at the Hammersmith Hospital in London and led to a series of collaborative studies at the start of a distinguished research career. This paper is dedicated to Ben de Pauw and also to the memory of my mentor, Roy Foord, who had the vision to go against his initial cautious instinct and allow me to convince him of the merits of these studies when combinations including aminoglycosides were standard. These initial studies also contributed to the concept of initial empirical monotherapy with re-appraisal at 48-72 h.
Collapse
Affiliation(s)
- Keith J Williams
- KW Drug Developments Ltd, Nightingale House, 5 Maplewood Road, Wilmslow, Cheshire SK9 2RY, UK.
| |
Collapse
|
43
|
Chen K, Liu ML, Schaffer L, Li M, Williams KJ. Abstract: 540 TYPE 2 DIABETES STRONGLY INDUCES HEPATIC OVEREXPRESSION OF SULF2, A NOVEL FACTOR THAT SUPPRESSES UPTAKE OF REMNANT LIPOPROTEINS. ATHEROSCLEROSIS SUPP 2009. [DOI: 10.1016/s1567-5688(09)70280-6] [Citation(s) in RCA: 2] [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: 11/30/2022]
|
44
|
Devgan PS, Diehl JF, Urick VJ, Sunderman CE, Williams KJ. Even-order harmonic cancellation for off-quadrature biased Mach-Zehnder modulator with improved RF metrics using dual wavelength inputs and dual outputs. Opt Express 2009; 17:9028-9039. [PMID: 19466152 DOI: 10.1364/oe.17.009028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We present a technique using a dual-output Mach-Zehnder modulator (MZM) with two wavelength inputs, one operating at low-bias and the other operating at high-bias, in order to cancel unwanted even-order harmonics in analog optical links. By using a dual-output MZM, this technique allows for two suppressed optical carriers to be transmitted to the receiver. Combined with optical amplification and balanced differential detection, the RF power of the fundamental is increased by 2 dB while the even-order harmonic is reduced by 47 dB, simultaneously. The RF noise figure and third-order spurious-free dynamic range (SFDR(3)) are improved by 5.4 dB and 3.6 dB, respectively. Using a wavelength sensitive, low V(pi) MZM allows the two wavelengths to be within 5.5 nm of each other for a frequency band from 10 MHz to 100 MHz and 10 nm for 1 GHz.
Collapse
Affiliation(s)
- Preetpaul S Devgan
- U S Naval Research Laboratory, 4555 Overlook Ave SW, Washington, D C 20375, USA.
| | | | | | | | | |
Collapse
|
45
|
Williams KJ, Bax RP. Challenges in developing new antibacterial drugs. Curr Opin Investig Drugs 2009; 10:157-163. [PMID: 19197793] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Regulatory guidelines for clinical development of antibacterial drugs have a major impact on decisions regarding research, influencing the degree to which novel targets are pursued, the choice of lead compounds, the spectrum of activity, as well as the dose. It is disconcerting that as pharmaceutical firms abandon antibacterial research and development, and expertise is lost from clinical, regulatory and commercial functions, biotechnology firms focus on easier, Gram-positive targets, which require limited clinical development, and expect pharmaceutical firms that have retreated from antibacterials to in-license compounds with restricted uses. Guidelines and incentives are needed to encourage development of agents targeted against the growing problem of Gram-negative bacterial resistance, as broad-spectrum drugs face even greater hurdles.
Collapse
Affiliation(s)
- Keith J Williams
- KW Drug Developments, Nightingale House, 5 Maplewood Road, Wilmslow, UK.
| | | |
Collapse
|
46
|
Williams KJ, Tait SJ, Ashley RM. In-sewer sedimentation associated with active flow control. Water Sci Technol 2009; 60:55-63. [PMID: 19587402 DOI: 10.2166/wst.2009.286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Active flow control using automated gates and weirs aims to utilise available dispersed storage within sewer systems to alleviate the severity and frequency of localised flooding incidents. Whilst a previous study has demonstrated its potential, a key operational concern before implementation was sedimentation. An experimental programme was designed to investigate the sediment deposition created when using a flow control device. Tests were also undertaken to examine the potential for rapid gate opening to flush away any resulting deposits. In catchments dominated by fine material in suspension, the use of an active flow control device can result in a uniformly thick deposit upstream of the gate. Rapid gate opening results in deposited material eroding in large sections starting at the gate and moving in an upstream direction. Granular sediment forms a series of discrete bedforms which are fairly uniform regardless of the flow conditions and a larger deposit further upstream. The potential for flushing granular deposits is limited and modification of the operation of the gate has shown little potential for increasing the effectiveness. Therefore, active flow control using a single downstream gate may only be suitable in systems with fine material moving in suspension during dry weather flow and not where there is significant granular sediment.
Collapse
Affiliation(s)
- K J Williams
- Pennine Water Group, Department of Civil and Structural Engineering, The University of Sheffield, Sheffield S1 3JD, UK.
| | | | | |
Collapse
|
47
|
Williams KJ, Telfer BA, Shannon AM, Babur M, Stratford IJ, Wedge SR. Inhibition of vascular endothelial growth factor signalling using cediranib (RECENTIN; AZD2171) enhances radiation response and causes substantial physiological changes in lung tumour xenografts. Br J Radiol 2008; 81 Spec No 1:S21-7. [PMID: 18819995 DOI: 10.1259/bjr/59853976] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
A number of pre-clinical studies have suggested that blocking vascular endothelial growth factor (VEGF) signalling can be beneficial in combination with radiotherapy. This study investigated the effects of cediranib, a highly potent orally available inhibitor of VEGF receptor tyrosine kinase activity in combination with radiation in Calu-6 lung xenografts. In nude mice, Calu-6 tumours were established and treatments initiated at a volume of 250 mm(3). Tumour-localized radiotherapy was given as three or five daily fractions of 2 Gy. Cediranib (3 mg kg(-1)) was administered 2 h prior to each fraction and continued post radiotherapy (concomitant regimen) or was initiated immediately after the completion of radiotherapy (sequential regimen). The endpoint was the time taken for tumour volume to quadruple (RTV4). Combined treatments resulted in a significantly enhanced growth delay compared with either modality alone. The therapeutic benefit was the same irrespective of the scheduling regimen. Tumour regression was observed post radiotherapy, which was associated with high levels of apoptosis and necrosis, and pronounced antivascular effects in histological samples. The amplified antivascular effect of cediranib when given after radiation suggests that pre-irradiated endothelium is sensitized to cediranib. Concomitant 5-day treatment with both cediranib and radiation reduced vessel density, perfusion and increased in tumour hypoxia. This was not associated with an acquired radioresistance suggesting that the maintenance of cediranib treatment post radiotherapy prevents the contribution of hypoxic cells to tumour regrowth. Collectively, these data support the contention that VEGFR inhibition can enhance radiation response in pre-clinical models and provide a rationale to develop cediranib in combination with radiotherapy in the clinical setting.
Collapse
Affiliation(s)
- K J Williams
- University of Manchester, School of Pharmacy, Manchester M13 9PT, UK.
| | | | | | | | | | | |
Collapse
|
48
|
Cowen RL, Garside EJ, Fitzpatrick B, Papadopoulou MV, Williams KJ. Gene therapy approaches to enhance bioreductive drug treatment. Br J Radiol 2008; 81 Spec No 1:S45-56. [DOI: 10.1259/bjr/55070206] [Citation(s) in RCA: 9] [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: 01/05/2023] Open
|
49
|
Williams KJ, Derksen FJ, de Feijter-Rupp H, Pannirselvam RR, Steel CM, Robinson NE. Regional pulmonary veno-occlusion: a newly identified lesion of equine exercise-induced pulmonary hemorrhage. Vet Pathol 2008; 45:316-26. [PMID: 18487488 DOI: 10.1354/vp.45-3-316] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Exercise-induced pulmonary hemorrhage (EIPH) is common in horses following intense exertion, occurring in up to 75% of racing Thoroughbreds and Standardbreds. In spite of this, the pathogenesis of EIPH is poorly understood. In 7 racing Thoroughbred horses with EIPH, 6 sections were collected from the left and right lung, representing the cranial, middle, and caudal region of the dorsal and ventral lung (84 sites total). Grossly, both right and left lungs had numerous dark brown to blue-black foci along the caudodorsal visceral pleura. Tissue sections were stained with hematoxylin-eosin, Masson's trichrome, and Prussian blue. Verhoeff Van Gieson and immunohistochemistry for alpha-smooth muscle actin were used to assess the pulmonary vasculature. Histologic scores (HS = 0-3) were assigned to each region/slide for the presence and severity of 5 findings: interstitial fibrosis, hemosiderin accumulation, pleural/interlobular septal thickness, arterial and venous wall thickness, and evidence of angiogenesis (maximum cumulative HS = 15). Thirty-nine of the 84 (46%) sections were histologically normal (HS = 0); 33/84 (39%) were mildly to moderately affected, with small amounts of hemosiderin and fibrosis (HS = 1-9) while 12/84 (14%), primarily from the dorsocaudal lung, had severe vascular remodeling, fibrosis, and hemosiderin accumulation (HS = 10-15). In the latter, veno-occlusive remodeling of the intralobular veins colocalized with hemosiderosis, fibrosis, hypertrophy of vessels within the pleura, and interlobular septa and bronchial neovascularization. We propose that regional veno-occlusive remodeling, especially within the caudodorsal lung fields, contributes to the pathogenesis of EIPH, with the venous remodeling leading to regional vascular congestion and hemorrhage, hemosiderin accumulation, fibrosis, and bronchial angiogenesis.
Collapse
Affiliation(s)
- K J Williams
- Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
| | | | | | | | | | | |
Collapse
|
50
|
Bogacki P, Oldach KH, Williams KJ. Expression profiling and mapping of defence response genes associated with the barley-Pyrenophora teres incompatible interaction. Mol Plant Pathol 2008; 9:645-60. [PMID: 19018994 PMCID: PMC6640259 DOI: 10.1111/j.1364-3703.2008.00485.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Barley net- and spot-form of net blotch disease are caused by two formae of the hemibiotrophic fungus Pyrenophora teres (P. t. f. teres and P. t. f. maculata). In the present study, suppression subtractive hybridization (SSH) was used in combination with quantitative real-time reverse transcriptase PCR to identify and profile the expression of defence response (DR) genes in the early stages of both barley-P. teres incompatible and compatible interactions. From a pool of 307 unique gene transcripts identified by SSH, 45 candidate DR genes were selected for temporal expression profiling in infected leaf epidermis. Differential expression profiles were observed for 28 of the selected candidates, which were grouped into clusters depending on their expression profiles within the first 48 h after inoculation. The expression profiles characteristic of each gene cluster were very similar in both barley-P. t. f. teres and barley-P. t. f. maculata interactions, indicating that resistance to both pathogens could be mediated by induction of the same group of DR genes. Chromosomal map locations for 21 DR genes were identified using four doubled-haploid mapping populations. The mapped DR genes were distributed across all seven barley chromosomes, with at least one gene mapping to within 15 cM of another on chromosomes 1H, 2H, 5H and 7H. Additionally, some DR genes appeared to co-localize with loci harbouring known resistance genes or quantitative trait loci for net blotch resistance on chromosomes 6H and 7H, as well as loci associated with resistance to other barley diseases. The DR genes are discussed with respect to their map locations and potential functional role in contributing to net blotch disease resistance.
Collapse
Affiliation(s)
- P Bogacki
- Molecular Plant Breeding CRC, South Australian Research and Development Institute, GPO Box 397, Adelaide, SA 5001, Australia.
| | | | | |
Collapse
|