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Rees C, Huang Y, De Boer A, Wessels B, Huppelschoten D, Zizolfi B, di Spiezio Sardo A, Christoforidis N, van Vliet H, Mischi M, Schoot B. Quantitative Ultrasound Measurement of Endometrial Waves in Adenomyosis Versus Women with Normal Uteri - the Waves Study. J Minim Invasive Gynecol 2022. [DOI: 10.1016/j.jmig.2022.09.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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De Boer A, Rees C, Blank C, Huang Y, Wessels B, Wagenaar L, Van Vliet H, Huppelschoten D, Zizolfi B, Foreste V, Di Spiezio Sardo A, Christoforidis N, Mischi M, Schoot B. P-333 The influence of hormonal stimulation on uterine peristalsis measured by ultrasound speckle tracking in women with IVF/ICSI treatment compared to normal ovulating women. Hum Reprod 2022. [DOI: 10.1093/humrep/deac107.317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Abstract
Study question
To investigate possible effects of ovarian stimulation during IVF/ICSI on uterine peristalsis features using ultrasound speckle tracking compared to normal ovulating women.
Summary answer
Patients with a normal uterus treated with exogenous hormones during IVF/ICSI treatment show significantly increased contraction amplitude and power parameters compared to normal ovulating women.
What is known already
Uterine peristalsis plays a role in procreation. Subjective visual inspection of uterine peristalsis is extensively researched throughout the menstrual cycle. Studies on uterine peristalsis in IVF/ICSI patients show higher frequency of uterine contractions during the periovulatory phase. Recently, a new automated quantitative method was validated to objectively analyse uterine strain using speckle tracking. Besides objective insight in frequency, also information on amplitude, power and coordination of motion is available. The effect of exogenous hormones on uterine contraction features has not objectively been studied using this new method.
Study design, size, duration
This multicentre prospective observational cohort study was performed between 2020 and 2022 in the Catharina Hospital in Eindhoven, the Netherlands, Embryolab Fertility Centre in Thessaloniki, Greece and University of Naples, Federico II in Naples, Italy. 30 normal ovulating patients served as controls. The primary outcomes were the contraction features frequency, amplitude, direction, velocity, power and coordination in women undergoing IVF/ICSI on the day of follicle aspiration compared to controls on cycle day 9 – 14.
Participants/materials, setting, methods
19 women undergoing IVF/ICSI were included regardless of the treatment cycle number and stimulation protocol. Indication for IVF/ICSI treatment was male subfertility (n = 8), idiopathic subfertility (n = 5), tubal factor (n = 2), primary ovarian insufficiency (n = 2) or combined (n = 2), all women had normal uteri on transvaginal ultrasound. The control group consisted of 30 healthy pre-menopausal women with normal uteri on ultrasound and spontaneous regular cycles.
Main results and the role of chance
Each patient underwent a 2.5 – 4 minute transvaginal ultrasound of the uterus in mid-sagittal plane. The various contraction features were extracted using a quantitative dedicated speckle tracking algorithm analysis studying motion of the subendometrial junctional zone.
Mean age of IVF/ICSI patients was 32.7 years and mean BMI was 25.6. Mean age of healthy controls was 33.8 years, BMI was 23.4, and cycle length was 27.44 days. Characteristics of IVF/ICSI patients and healthy volunteers showed no statistically significant differences. Both groups predominantly consisted of nulliparous women.
In IVF/ICSI patients the contraction amplitude was significantly higher compared to controls (0.062 vs 0.040; p < 0.001). The contraction power (combination of amplitude and frequency) appeared to be significantly higher in IVF/ICSI patients compared to controls (1528.18 vs 683.44; p < 0.001). No significant differences were found in contraction frequency and coordination. Even though the mean coordination did not show statistically significant differences, the values were less scattered in IVF/ICSI patients, with a much smaller range of coordination values (1.04 – 3.06) compared to healthy volunteers (1.02 – 50.33).
Limitations, reasons for caution
The reported difference between IVF/ICSI patients and controls in contraction amplitude and power may not solely be attributed to the administration of exogenous hormones. The difference may also be due to an underlying cause for infertility in these patients. Another limitation of this study is the small sample size.
Wider implications of the findings
Future research should explore which uterine contraction profile is associated with viable pregnancy: during the natural menstrual cycle, or when treated with hormones. The question arises whether it is preferred to transfer the embryo in the stimulated cycle or implement a freeze-all policy and transfer during the natural menstrual cycle.
Trial registration number
NCT02310802
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Affiliation(s)
- A De Boer
- Catharina Hospital, Gynaecology and Obstetrics , Eindhoven, The Netherlands
| | - C Rees
- Catharina Hospital, Gynaecology and Obstetrics , Eindhoven, The Netherlands
| | - C Blank
- Catharina Hospital, Gynaecology and Obstetrics , Eindhoven, The Netherlands
| | - Y Huang
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - B Wessels
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - L Wagenaar
- Catharina Hospital, Gynaecology and Obstetrics , Eindhoven, The Netherlands
| | - H Van Vliet
- Ghent University Hospital, Gynaecology and Obstetrics , Ghent, Belgium
| | - D Huppelschoten
- Catharina Hospital, Gynaecology and Obstetrics , Eindhoven, The Netherlands
| | - B Zizolfi
- University of Naples Federico II, Department of Public Health- School of Medicine , Naples, Italy
| | - V Foreste
- University of Naples Federico II, Department of Public Health- School of Medicine , Naples, Italy
| | - A Di Spiezio Sardo
- University of Naples Federico II, Department of Public Health- School of Medicine , Naples, Italy
| | | | - M Mischi
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - B.C Schoot
- Ghent University Hospital, Gynaecology and Obstetrics , Ghent, Belgium
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Schoot B, Rees C, Huang Y, De Boer A, Wessels B, Huppelschoten D, Zizolfi B, Di Spiezio Sardo A, Christoforidos N, Van Vliet H, Mischi M. P-305 Uterine contractile function across the menstrual cycle in healthy women: an exploration of objective reference values of sub-endometrial motion using speckle tracking. Hum Reprod 2022. [DOI: 10.1093/humrep/deac107.291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Abstract
Study question
To explore the characteristics of normal uterine contractile function across the menstrual cycle in healthy women using a novel quantitative ultrasound method.
Summary answer
We confirm reproducible differences in uterine contractility across the menstrual cycle; highest activity seen in the periovulatory phase, and lowest in the late luteal phase.
What is known already
Uterine peristalsis is the rhythmic, wave-like motion of the subendometrial layer of the uterus. Various subjective methods using visual interpretation suggest that uterine peristalsis features are different in the various stages of the menstrual cycle, and they are thought to be important for fertility. However, no method has been developed which can assess all uterine contraction features simultaneously. Recently, a new automated quantitative method to measure uterine contractility was validated in IVF patients to analyse uterine peristalsis on transvaginal ultrasound recordings with speckle-tracking. With this method a new contraction feature – coordination – can be assessed alongside frequency, direction, amplitude.
Study design, size, duration
Multi-centre observational prospective cohort study carried out in the outpatient gynaecology department of the Catharina Hospital in Eindhoven, the Netherlands, the University of Naples, Federico II, Naples, Italy and Embryolab Fertility centre in Thessaloniki, Greece. Patients were included from September 2020 up to January 2022. Primary outcomes were the contraction frequency (contractions/minute), amplitude, direction (Cervix-to-fundus, Fundus-to-cervix), and coordination.
Participants/materials, setting, methods
63 women were included from the gynaecological department of participating centres. Women were included if they were ≥18 years of age, premenopausal and had a normal, natural menstrual cycle. A normal cycle was defined as: regular (duration ± 28 days), no dysmenorrhea, no menometrorrhagia. Transvaginal ultrasounds were performed during the menstrual phase (M), late follicular (periovulatory) phase (LF), early luteal phase (EL, ovulation + 3 days) and/or late luteal phase (LL, ovulation + 7 days).
Main results and the role of chance
Uterine contractility features were extracted from the gathered ultrasound recordings using a quantitative dedicated speckle tracking algorithm previously developed by our group. Each patient underwent a four-minute ultrasound of the uterus in mid-sagittal section. Patients had a mean age of 32 years, cycle duration of 27.8, and BMI of 23.0. The majority of women was nulliparous. The majority of uterine contraction features differed significantly between menstrual cycle phases. Contraction frequency was highest in the LF phase and lowest in the M and LL phases (1.55 vs. 1.28/min, p = 0.001). A trend was found for contractions during the periovulatory and early luteal phases contractions to travel mainly from cervix-to-fundus direction, whilst the menstrual phase showed contractions mainly from the fundus to cervix (p > 0.05). No significant difference between phases was found for contraction amplitude. Contraction coordination (simultaneous contraction of the anterior and posterior walls in the same direction) was highest in the periovulatory phase (p = 0.002). Our results are in line with with previous published studies using subjective visual inspection.
Limitations, reasons for caution
This is the first study investigating contraction coordination as a specific feature of uterine peristalsis. Not all patients were available for multiple ultrasounds during the same cycle, thereby a within-subjects comparison of the uterine contractions was not possible.
Wider implications of the findings
We explored further implementation of a quantitative method of uterine peristalsis measurement. Our investigation of a novel contraction characteristic - coordination - opens up possibilities for research and a potential etiological/treatment target. Further research using this method and suggested reference values will provide insight into contraction characteristics in abnormal uteri.
Trial registration number
NCT02310802
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Affiliation(s)
- B Schoot
- Catharina Ziekenhuis, dept OB/GYN , Eindhoven, The Netherlands
- Uz Ghent, Dept OB/GYN , Ghent, Belgium
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - C Rees
- Catharina Ziekenhuis, dept OB/GYN , Eindhoven, The Netherlands
| | - Y Huang
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - A De Boer
- Catharina Ziekenhuis, dept OB/GYN , Eindhoven, The Netherlands
| | - B Wessels
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
| | - D Huppelschoten
- Catharina Ziekenhuis, dept OB/GYN , Eindhoven, The Netherlands
| | - B Zizolfi
- University of Naples Federico II, Department of Public Health- School of Medicine , Naples, Italy
| | - A Di Spiezio Sardo
- University of Naples Federico II, Department of Public Health- School of Medicine , Naples, Italy
| | | | - H Van Vliet
- Catharina Ziekenhuis, dept OB/GYN , Eindhoven, The Netherlands
- Uz Ghent, Dept OB/GYN , Ghent, Belgium
| | - M Mischi
- Eindhoven University of Technology, Electrical Engineering , Eindhoven, The Netherlands
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Wessels B, Seyfferth C, Escamez S, Vain T, Antos K, Vahala J, Delhomme N, Kangasjärvi J, Eder M, Felten J, Tuominen H. An AP2/ERF transcription factor ERF139 coordinates xylem cell expansion and secondary cell wall deposition. New Phytol 2019; 224:1585-1599. [PMID: 31125440 DOI: 10.1111/nph.15960] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2019] [Accepted: 05/19/2019] [Indexed: 05/14/2023]
Abstract
Differentiation of xylem elements involves cell expansion, secondary cell wall (SCW) deposition and programmed cell death. Transitions between these phases require strict spatiotemporal control. The function of Populus ERF139 (Potri.013G101100) in xylem differentiation was characterized in transgenic overexpression and dominant repressor lines of ERF139 in hybrid aspen (Populus tremula × tremuloides). Xylem properties, SCW chemistry and downstream targets were analyzed in both types of transgenic trees using microscopy techniques, Fourier transform-infrared spectroscopy, pyrolysis-GC/MS, wet chemistry methods and RNA sequencing. Opposite phenotypes were observed in the secondary xylem vessel sizes and SCW chemistry in the two different types of transgenic trees, supporting the function of ERF139 in suppressing the radial expansion of vessel elements and stimulating accumulation of guaiacyl-type lignin and possibly also xylan. Comparative transcriptomics identified genes related to SCW biosynthesis (LAC5, LBD15, MYB86) and salt and drought stress-responsive genes (ANAC002, ABA1) as potential direct targets of ERF139. The phenotypes of the transgenic trees and the stem expression profiles of ERF139 potential target genes support the role of ERF139 as a transcriptional regulator of xylem cell expansion and SCW formation, possibly in response to osmotic changes of the cells.
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Affiliation(s)
- Bernard Wessels
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, SE-90187, Sweden
| | - Carolin Seyfferth
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, SE-90187, Sweden
| | - Sacha Escamez
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, SE-90187, Sweden
| | - Thomas Vain
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Kamil Antos
- Department of Integrative Medical Biology, Umeå University, Umeå, SE-90187, Sweden
| | - Jorma Vahala
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, VIPS, University of Helsinki, Viikinkaari 1 (POB65), Helsinki, FI-00014, Finland
| | - Nicolas Delhomme
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, Viikki Plant Science Centre, VIPS, University of Helsinki, Viikinkaari 1 (POB65), Helsinki, FI-00014, Finland
| | - Michaela Eder
- Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, 14476, Germany
| | - Judith Felten
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, SE-90183, Sweden
| | - Hannele Tuominen
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, SE-90187, Sweden
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Seyfferth C, Wessels B, Jokipii-Lukkari S, Sundberg B, Delhomme N, Felten J, Tuominen H. Ethylene-Related Gene Expression Networks in Wood Formation. Front Plant Sci 2018; 9:272. [PMID: 29593753 PMCID: PMC5861219 DOI: 10.3389/fpls.2018.00272] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 02/16/2018] [Indexed: 05/27/2023]
Abstract
Thickening of tree stems is the result of secondary growth, accomplished by the meristematic activity of the vascular cambium. Secondary growth of the stem entails developmental cascades resulting in the formation of secondary phloem outwards and secondary xylem (i.e., wood) inwards of the stem. Signaling and transcriptional reprogramming by the phytohormone ethylene modifies cambial growth and cell differentiation, but the molecular link between ethylene and secondary growth remains unknown. We addressed this shortcoming by analyzing expression profiles and co-expression networks of ethylene pathway genes using the AspWood transcriptome database which covers all stages of secondary growth in aspen (Populus tremula) stems. ACC synthase expression suggests that the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) is synthesized during xylem expansion and xylem cell maturation. Ethylene-mediated transcriptional reprogramming occurs during all stages of secondary growth, as deduced from AspWood expression profiles of ethylene-responsive genes. A network centrality analysis of the AspWood dataset identified EIN3D and 11 ERFs as hubs. No overlap was found between the co-expressed genes of the EIN3 and ERF hubs, suggesting target diversification and hence independent roles for these transcription factor families during normal wood formation. The EIN3D hub was part of a large co-expression gene module, which contained 16 transcription factors, among them several new candidates that have not been earlier connected to wood formation and a VND-INTERACTING 2 (VNI2) homolog. We experimentally demonstrated Populus EIN3D function in ethylene signaling in Arabidopsis thaliana. The ERF hubs ERF118 and ERF119 were connected on the basis of their expression pattern and gene co-expression module composition to xylem cell expansion and secondary cell wall formation, respectively. We hereby establish data resources for ethylene-responsive genes and potential targets for EIN3D and ERF transcription factors in Populus stem tissues, which can help to understand the range of ethylene targeted biological processes during secondary growth.
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Affiliation(s)
- Carolin Seyfferth
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Bernard Wessels
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Soile Jokipii-Lukkari
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Björn Sundberg
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Nicolas Delhomme
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Judith Felten
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Umeå, Sweden
| | - Hannele Tuominen
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
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Cheng C, Lee S, Muzic R, Wessels B, Jesseph F, Ellis R, Mansur D, Dhanantwari A. SU-F-J-210: A Preliminary Study On the Dosimetric Impact of Detector Based Spectral Ct On Proton Therapy Treatment Planning. Med Phys 2016. [DOI: 10.1118/1.4956118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Zheng Y, Yuan J, Geis P, Colussi V, Machtay M, Ellis R, Wessels B. SU-F-T-467: A Cross-Checking Approach for Dosimetric Verification of Beam- Matched Elekta Linear Accelerators. Med Phys 2016. [DOI: 10.1118/1.4956652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Cheng C, Wessels B, Jesseph F, Mattson D, Mansur D. SU-E-T-615: Plan Comparison Between Photon IMRT and Proton Plans Incorporating Uncertainty Analysis. Med Phys 2015. [DOI: 10.1118/1.4924978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Cheng C, Wessels B, Mansur D, Machtay M. SU-F-BRD-02: Incorporating Uncertainty Analysis in Plan Comparison of VMAT, Double Scattering Proton Plan and IMPT for Lung Irradiation. Med Phys 2015. [DOI: 10.1118/1.4925181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Yuan J, Zhang Y, Zheng Y, Wessels B, Machtay M, Yao M, Lo S. SU-E-T-404: Evaluation of the Effect of Spine Hardware for CyberKnife Spinal Stereotactic Radiosurgery. Med Phys 2015. [DOI: 10.1118/1.4924765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Wessels B, Ciapaite J, van den Broek NMA, Houten SM, Nicolay K, Prompers JJ. Pioglitazone treatment restores in vivo muscle oxidative capacity in a rat model of diabetes. Diabetes Obes Metab 2015; 17:52-60. [PMID: 25200673 DOI: 10.1111/dom.12388] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 08/27/2014] [Accepted: 09/02/2014] [Indexed: 12/15/2022]
Abstract
AIM To determine the effect of pioglitazone treatment on in vivo and ex vivo muscle mitochondrial function in a rat model of diabetes. METHODS Both the lean, healthy rats and the obese, diabetic rats are Zucker Diabetic Fatty (ZDF) rats. The homozygous fa/fa ZDF rats are obese and diabetic. The heterozygous fa/+ ZDF rats are lean and healthy. Diabetic Zucker Diabetic Fatty rats were treated with either pioglitazone (30 mg/kg/day) or water as a control (n = 6 per group), for 2 weeks. In vivo ¹H and ³¹P magnetic resonance spectroscopy was performed on skeletal muscle to assess intramyocellular lipid (IMCL) content and muscle oxidative capacity, respectively. Ex vivo muscle mitochondrial respiratory capacity was evaluated using high-resolution respirometry. In addition, several markers of mitochondrial content were determined. RESULTS IMCL content was 14-fold higher and in vivo muscle oxidative capacity was 26% lower in diabetic rats compared with lean rats, which was, however, not caused by impairments of ex vivo mitochondrial respiratory capacity or a lower mitochondrial content. Pioglitazone treatment restored in vivo muscle oxidative capacity in diabetic rats to the level of lean controls. This amelioration was not accompanied by an increase in mitochondrial content or ex vivo mitochondrial respiratory capacity, but rather was paralleled by an improvement in lipid homeostasis, that is lowering of plasma triglycerides and muscle lipid and long-chain acylcarnitine content. CONCLUSION Diminished in vivo muscle oxidative capacity in diabetic rats results from mitochondrial lipid overload and can be alleviated by redirecting the lipids from the muscle into adipose tissue using pioglitazone treatment.
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Affiliation(s)
- B Wessels
- Department of Biomedical Engineering, Biomedical NMR, Eindhoven University of Technology, Eindhoven, the Netherlands
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Wessels B, Seger W. [Clinical reasoning supportive to a medical service provider as a tool for complaint management: a case study for pragmatic reasoning]. Gesundheitswesen 2014; 76:813-8. [PMID: 25397910 DOI: 10.1055/s-0034-1390433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The process of "clinical reasoning" is exemplified as supportive to the complaint management of the Statutory Medical Health Advisory Board in Lower Saxony, Germany, within the operational division for long-term care insurance. A model case from real life illustrates in detail the hypothetical-deductive approach by Beusheusen and Klemme/Siegmann. Because of the potential area of conflicts between human concern in the case of a long-term care burden and legal requirements, the process was analysed in terms of a pragmatic reasoning. Human resources of the claimant and persons in charge at customer's service were demonstrated as well as political, statutory and institutional determining factors. Concluding self-perception validates the process in the context of evidence-based practice.
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Affiliation(s)
- B Wessels
- Ressourcenmanagement Pflege, MDK Niedersachsen, Hannover
| | - W Seger
- Ärztliche Leitung, MDK Niedersachsen, Hannover
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Yuan J, Chen Q, Zheng Y, Sohn J, Wessels B. SU-E-T-349: Verification of a Monte Carlo Simulation Tool as a Second Check for TomoTherapy Treatment Planning. Med Phys 2014. [DOI: 10.1118/1.4888682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Cheng C, Wessels B, Hamilton H, Difranco T, Mansur D. SU-E-T-419: Workflow and FMEA in a New Proton Therapy (PT) Facility. Med Phys 2014. [DOI: 10.1118/1.4888752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Kim H, Yao M, Monroe J, Lo S, Wessels B, Zhang Y, Machtay M, Sohn J. Case Studies Presenting Dosimetric Uncertainties Using Fuzzy Set Theory. Int J Radiat Oncol Biol Phys 2013. [DOI: 10.1016/j.ijrobp.2013.06.1839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Albani D, Fabien J, Brindle J, Zhang Y, Dobbins D, Wessels B, Ellis R, Podder T. SU-E-T-432: Dosimetric Computation of Cyberknife SBRT Plans for Treatment of Kidney and Adrenal Gland. Med Phys 2013. [DOI: 10.1118/1.4814866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Fabien J, Zhang Y, Brindle J, Dobbins D, Podder T, Wessels B. SU-D-105-01: Patient-Specific Quality Assurance for Monte Carlo-Calculated Lung SBRT On Cyberknife - Is It Necessary? Med Phys 2013. [DOI: 10.1118/1.4813997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Bao A, Zheng Y, Ellis R, Fabien J, Rhodes C, Colussi V, Wessels B. SU-E-T-263: MRI-Guided Targeted Prostate Cancer Radiation Therapy: Multi-Image Co-Registration. Med Phys 2013. [DOI: 10.1118/1.4814698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Bao A, Zheng Y, Ware S, Colussi V, Ellis R, Wessels B. SU-E-J-90: MRI-Guided Targeted Prostate Cancer Radiation Therapy: Imaging, Diagnosis, and Image Co-Registration. Med Phys 2013. [DOI: 10.1118/1.4814302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Schmitz JPJ, Groenendaal W, Wessels B, Wiseman RW, Hilbers PAJ, Nicolay K, Prompers JJ, Jeneson JAL, van Riel NAW. Combined in vivo and in silico investigations of activation of glycolysis in contracting skeletal muscle. Am J Physiol Cell Physiol 2012; 304:C180-93. [PMID: 23114964 DOI: 10.1152/ajpcell.00101.2012] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The hypothesis was tested that the variation of in vivo glycolytic flux with contraction frequency in skeletal muscle can be qualitatively and quantitatively explained by calcium-calmodulin activation of phosphofructokinase (PFK-1). Ischemic rat tibialis anterior muscle was electrically stimulated at frequencies between 0 and 80 Hz to covary the ATP turnover rate and calcium concentration in the tissue. Estimates of in vivo glycolytic rates and cellular free energetic states were derived from dynamic changes in intramuscular pH and phosphocreatine content, respectively, determined by phosphorus magnetic resonance spectroscopy ((31)P-MRS). Computational modeling was applied to relate these empirical observations to understanding of the biochemistry of muscle glycolysis. Hereto, the kinetic model of PFK activity in a previously reported mathematical model of the glycolytic pathway (Vinnakota KC, Rusk J, Palmer L, Shankland E, Kushmerick MJ. J Physiol 588: 1961-1983, 2010) was adapted to contain a calcium-calmodulin binding sensitivity. The two main results were introduction of regulation of PFK-1 activity by binding of a calcium-calmodulin complex in combination with activation by increased concentrations of AMP and ADP was essential to qualitatively and quantitatively explain the experimental observations. Secondly, the model predicted that shutdown of glycolytic ATP production flux in muscle postexercise may lag behind deactivation of PFK-1 (timescales: 5-10 s vs. 100-200 ms, respectively) as a result of accumulation of glycolytic intermediates downstream of PFK during contractions.
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Affiliation(s)
- J P J Schmitz
- Computational Biology, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.
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21
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Zheng Y, Yuan J, Woods C, Machtay M, Wessels B. SU-E-T-460: Isoeffective Dose Display (EQD2) for Composite Plan of Radiosurgery and Conventional 3D Radiotherapy. Med Phys 2012; 39:3810-3811. [DOI: 10.1118/1.4735549] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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22
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Yuan J, Brindle J, Zheng Y, Sohn J, Geis P, Yao M, Lo S, Wessels B. SU-C-211-02: A Fast Monte Carlo Dose Algorithm for Radiotherapy Treatment Planning Based on Hybrid Adaptive Meshes. Med Phys 2012. [DOI: 10.1118/1.4734601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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23
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Rhodes C, Campbell S, Shields W, Fabien J, Colussi V, Wessels B. SU-E-T-600: Utilizing Collimator Rotation to Increase Maximum Treatable Target Dimensions Using an Elekta Synergy-S with Beam Modulator Multileaf Collimator. Med Phys 2012; 39:3844. [DOI: 10.1118/1.4735689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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24
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Zheng Y, Zhang Y, Brindle J, Fabien J, Chen W, Woods C, Galanopoulos N, Choe J, Kunos C, Ellis R, Ponsky L, Funkhouser G, Machtay M, Einstein D, Wessels B. SU-E-T-644: Software Tool Used in Setting Optimization Control Points for Hypofractionated CyberKnife Treatment Planning. Med Phys 2011. [DOI: 10.1118/1.3612607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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25
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Fabien J, Zheng Y, Anton L, Colussi V, Shields C, Shields G, Wessels B. SU-E-T-258: Comparison of Dosimetric Characteristics Between Elekta Synergy Linear Accelerators with MLCi and Beam Modulator Collimator Heads. Med Phys 2011. [DOI: 10.1118/1.3612209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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26
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Choe J, Chen W, Woods C, Wessels B, Zheng Y, Brindle J, Zhang Y, Kunos C, Lyons J, Einstein D. Toxicity Data For Hypofractionated Radiosurgery Using the Linear Quadratic Model to Constrain Normal Organ Tolerance Doses. Int J Radiat Oncol Biol Phys 2010. [DOI: 10.1016/j.ijrobp.2010.07.348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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27
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Einstein D, Wessels B, Bangert B, Lewin J, Nelson A, Fu P, Cohen M, Sagar S, Zhang Y, Maciunas R. Phase II Trial Combining Conventional Radiotherapy with Stereotactic Radiosurgery to High-risk Tumor Regions as Determined by MR Spectroscopy for Patients with Glioblastoma Multiforme. Int J Radiat Oncol Biol Phys 2009. [DOI: 10.1016/j.ijrobp.2009.07.299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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28
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Ponsky LE, Lillibridge C, Brindle J, Zhang Y, Wessels B, Einstein DB. Stereotactic robotic radiosurgery for localized prostate cancer: Initial evaluation of acute toxicities. J Clin Oncol 2009. [DOI: 10.1200/jco.2009.27.15_suppl.e16006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
e16006 Background: We evaluated the initial acute toxicities experienced by patients treated with cyberknife fractionated radiosurgery for low and low-intermediate risk prostate cancer. Methods: Twenty-two patients with low or low-intermediate risk prostate cancer (T2a, GG 3+3=6 or 3+4=7, PSA <10) were enrolled prospectively on an IRB approved protocol and treated the planning target volume (PTV)(prostate+5mm margin) with cyberknife fractionated radiosurgery to a dose of 36.25 Gy in 5 fractions (7.25Gy/fraction). The target volume included the prostate and seminal vesicles. PSA values, AUA symptom scores (AUA SS), and NCI CTC acute toxicities were analyzed prior to radiosurgery and at 1 month (N=16), 3 months (N=12) and 6 months (N=5)post-treatment. Results: Patients treated on study included 12 with GG 3+3=6 cancer and 10 with GG 3+4=7 cancer. Mean patient age was 66 years old (range 49–79). Mean pre-treatment PSA was 5.29 (range 0.64–9.36) declining to 3.44 (range 0.00–10.43) at 1 month post treatment, 1.99 (range 0.31–3.99) at 3 months post-treatment and 2.08 (1.05–3.13) at 6 months post-treatment. Mean pre-treatment AUA SS was 7 (range 0.–18) increasing to 12 (range 2–29) at 1 month post treatment, decreasing to 8 (range 2–17) at 3 months post-treatment and 11 (3–17). There were 5 grade 1 acute toxicities including (diarrhea, fatigue, mild urinary frequency, hemorrhoid and a rash) and 7 grade 2 toxicities including (bladder spasms, painful urinary, bowel irregularity, rectal pain, urethritis and numbness in the upper thigh), all grade 1 and 2 toxicities resolved within three months of treatment. The one patient with grade 2 thigh numbness was not thought to be study related toxicity. Two patients developed grade 3 toxicity. One developed bacteremia after the transrectal ultrasound guided placement of the fiducials, the infection completely resolved after treatment with antibiotics. One patient on Coumadin developed hematuria which resolved with conservative management. Conclusions: Cyberknife fractionated radiosurgery for patients with early stage prostate cancer appears to be safe on our early initial assessment.Continued evaluation and longer follow-up ongoing. [Table: see text]
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Affiliation(s)
- L. E. Ponsky
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
| | - C. Lillibridge
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
| | - J. Brindle
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
| | - Y. Zhang
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
| | - B. Wessels
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
| | - D. B. Einstein
- University Hospital Case Medical Center, Cleveland, OH; University Hospitals Case Medical Center, Cleveland, OH
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Petoussi-Henss N, Bolch WE, Zankl M, Sgouros G, Wessels B. Patient-specific scaling of reference S-values for cross-organ radionuclide S-values: what is appropriate? Radiat Prot Dosimetry 2007; 127:192-6. [PMID: 17569687 DOI: 10.1093/rpd/ncm270] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The Medical Internal Radiation Dose Committee (MIRD) formalism assumes reference mass values for the organs (source and target) and the total body. MIRD publication 11 provides guidance on how patient-specific scaling of reference radionuclide S-values are to be performed for the electron component of the emission spectrum. However, guidance on patient-specific scaling of the photon contributions to the S-value is given only for those cases where the source and target organs are either far apart or are the same. The photon component of the S-value is derived from photon-Specific Absorbed Fractions (SAFs). These are obtained by Monte Carlo calculation of photon transport. The objective of this work is to verify the MIRD 11 guidance and to examine the relationship between photon SAFs and source/target organ mass when the conditions listed above do not apply. Furthermore, the scaling for photon cross-dose to distributed organs is at present not defined due to lack of data for models other than the reference model. The validity of mass scaling for cross irradiation from near and distant photons sources, especially for Red Bone Marrow (RBM) as a target tissue is also investigated. This is achieved by comparing Monte Carlo-derived SAFs for different source organs to RBM across the GSF voxel phantom series. The results show that, for photon energies greater than 100 keV, the SAF of most source organs to RBM need not be corrected for target mass (error < 5%). In contrast to the results obtained for well-defined source organs, the SAF for RBM irradiating RBM gives a deviation of up to 16% across the different GSF voxel phantoms.
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Affiliation(s)
- Nina Petoussi-Henss
- GSF-National Research Center for Environment and Health, Institute of Radiation Protection, Ingolstaedter Landstr. 1, 85764 Neuherberg, Germany.
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Syh J, White B, Pillai K, Colussi V, Sohn J, Zheng Y, Einstein D, Maciunas R, Wessels B. SU-FF-T-63: A Study of Effectiveness of Stereotactic Head Frame Distortion On the Gamma Knife Automatic Positioning System by Stress of Screw Fixation. Med Phys 2006. [DOI: 10.1118/1.2240990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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31
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Sohn J, Luo C, Monroe J, Pillai K, Einstein D, Wessels B, Kinsella T. SU-FF-J-39: Comparison of Patient Positioning Corrections For Prostate IMRT Patients Using Competing Image Guided Radiation Therapy Technologies. Med Phys 2006. [DOI: 10.1118/1.2240817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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32
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Changkon V, Jitprapaikulsarn S, Thongphiew D, Wessels B, Wu Q. TU-C-T-617-01: A Computer Model for Automatic Planning and Optimization for Gamma Knife Radiosurgery Using Auto-Positioning System. Med Phys 2005. [DOI: 10.1118/1.1999759] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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33
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Sohn J, Kim S, Monroe J, Chvetsov A, Wessels B. WE-D-I-6B-07: Human and System Error Analysis of a 3D Optical Laser Scanning System for Image-Guided Patient Positioning. Med Phys 2005. [DOI: 10.1118/1.1998543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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34
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Monroe J, Hainfeld J, Sohn J, Wessels B. SU-FF-T-314: Initial Monte Carlo Analysis of the Dosimetric Effects of Gold Nanoparticle Radiosensitizers. Med Phys 2005. [DOI: 10.1118/1.1998043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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35
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Tang P, Towner D, Hamano T, Meier A, Wessels B. Electrooptic modulation up to 40 GHz in a barium titanate thin film waveguide modulator. Opt Express 2004; 12:5962-5967. [PMID: 19488237 DOI: 10.1364/opex.12.005962] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The high frequency operation of a low-voltage electrooptic modulator based on a strip-loaded BaTiO3 thin film waveguide structure has been demonstrated. The epitaxial BaTiO3 thin film on an MgO substrate forms a composite structure with a low effective dielectric constant of 20.8 at 40 GHz. A 3.9 V half-wave voltage with a 3.7 GHz 3-dB bandwidth and a 150 pm/V effective electrooptic coefficient is obtained for the 3.2mm-long modulator at 1.55 ?m. Broadband modulation up to 40 GHz is measured with a calibrated detection system. Numerical simulations indicate that the BaTiO3 thin film modulator has the potential for a 3-dB operational bandwidth in excess of 40 GHz through optimized design.
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36
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Ellis RJ, Kim EY, Conant R, Sodee DB, Spirnak JP, Dinchman KH, Beddar S, Wessels B, Resnick MI, Kinsella TJ. Radioimmunoguided imaging of prostate cancer foci with histopathological correlation. Int J Radiat Oncol Biol Phys 2001; 49:1281-6. [PMID: 11286835 DOI: 10.1016/s0360-3016(00)01582-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE We have previously presented a technique that fuses ProstaScint and pelvic CT images for the purpose of designing brachytherapy that targets areas at high risk for treatment failure. We now correlate areas of increased intensity seen on ProstaScint-CT fusion images to biopsy results in a series of 7 patients to evaluate the accuracy of this technique in localizing intraprostatic disease. METHODS AND MATERIALS The 7 patients included in this study were evaluated between June 1998 and March 29, 1999 at Metrohealth Medical Center and University Hospitals of Cleveland in Cleveland, Ohio. ProstaScint and CT scans of each patient were obtained before transperineal biopsy and seed implantation. Each patient's prostate gland was biopsied at 12 separate sites determined independently of Prostascint-CT scan results. RESULTS When correlated with biopsy results, our method yielded an overall accuracy of 80%: with a sensitivity of 79%, a specificity of 80%, a positive predictive value of 68%, and a negative predictive value of 88%. CONCLUSION The image fusion of the pelvic CT scan and ProstaScint scan helped identify foci of adenocarcinoma within the prostate that correlated well with biopsy results. These data may be useful to escalate doses in regions containing tumor by either high-dose rate or low-dose rate brachytherapy, as well as by external beam techniques such as intensity modulated radiotherapy (IMRT).
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Affiliation(s)
- R J Ellis
- Department of Radiation Oncology, University Hospitals of Cleveland, Cleveland, OH 44106, USA.
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37
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Sgouros G, Stabin M, Erdi Y, Akabani G, Kwok C, Brill AB, Wessels B. Red marrow dosimetry for radiolabeled antibodies that bind to marrow, bone, or blood components. Med Phys 2000; 27:2150-64. [PMID: 11011745 DOI: 10.1118/1.1288393] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Hematologic toxicity limits the radioactivity that may be administered for radiolabeled antibody therapy. This work examines approaches for obtaining biodistribution data and performing dosimetry when the administered antibody is known to bind to a cellular component of blood, bone, or marrow. Marrow dosimetry in this case is more difficult because the kinetics of antibody clearance from the blood cannot be related to the marrow. Several approaches for obtaining antibody kinetics in the marrow are examined and evaluated. The absorbed fractions and S factors that should be used in performing marrow dosimetry are also examined and the effect of including greater anatomical detail is considered. The radiobiology of the red marrow is briefly reviewed. Recommendations for performing marrow dosimetry when the antibody binds to the marrow are provided.
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Affiliation(s)
- G Sgouros
- Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York 10021, USA.
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Abstract
PURPOSE The dose distribution in small lung lesions (coin lesions) is determined by the combined effects of reduced attenuation and electronic disequilibrium. The magnitude of the dose delivered also depends on the algorithm used to correct for reduced lung density. These effects are investigated experimentally and computationally for 10 MV photons. METHODS AND MATERIALS Using a polystyrene miniphantom embedded in cork or cedar, thermoluminescent dosimetry and film dosimetry was performed to investigate interface effects and the central dose per monitor unit (MU). Three frequently applied calculation techniques--no density correction, ratio of tissue maximum ratios (TMRs), and the Batho correction--were also used to calculate the dose per MU. The measurements and calculations were compared with a one-dimensional phenomenological theory with parameters taken from the literature. RESULTS The measurements at the entrance surface and center of the miniphantom agreed well with the predictions of the phenomenological theory. The interface regions are usually thin enough (2-3 mm) to be clinically unimportant for 10 MV. Depending on the algorithm used to correct for decreased lung density, the lesion dose may be larger or smaller than the prescribed dose by as much as 20% in extreme cases. A clinical example is presented. CONCLUSIONS In comparing clinical results of treatments of small lung lesions, it is important to be aware of the density correction used.
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Affiliation(s)
- E Yorke
- George Washington University Medical Center, Division of Radiation Oncology and Biophysics, Washington, DC 20037, USA
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