Sample records for afterloading

  1. Afterloading: The Technique That Rescued Brachytherapy

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    Aronowitz, Jesse N., E-mail:


    Although brachytherapy had been established as a highly effective modality for the treatment of cancer, its application was threatened by mid-20th century due to appreciation of the radiation hazard to health care workers. This review examines how the introduction of afterloading eliminated exposure and ushered in a brachytherapy renaissance.

  2. Current status of afterloading in gynecological contact therapy

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    Bauer, M.; Fournier, D. von; Schulz-Wendtland, R.; Kuttig, H.; Junkermann, H.


    The present state of the remote-controlled afterloading technique is described. Beside the description of the development and the advantages of this method we discuss the currently available afterloading equipment as well as the appropriate radionuclids. The simulation of the treatment of the classic schools from Paris, Stockholm and Manchester is demonstrated by means of proper application combinations. Finally advantages and disadvantages of the HDR and LDR-treatment - especially in regard to radio-biological effects - are discussed.

  3. Technique of after-loading interstitial implants. (United States)

    Syed, A M; Feder, B H


    Interstitial implants are either removable or permanent (and occasionally a combination of both). Permanent implants are generally utilized where tumors are not accessible enough to permit easy removal of sources or where accurate source distribution is less critical. They are useful for cancers of the lung, pancreas, prostate, bladder, lymph nodes, etc. Radon and gold-198 have been largely replaced by iodine-125. Our major interests are in the removable after-loading iridium-192 implant techniques. Template (steel guide) and non-template (plastic tube) techniques are utilized. Templates are preferred where the tumor volume can only be approached from one side and where accurate positioning of sources would otherwise be difficult. They are useful for cancers of the cervix, vagina, urethra, and rectum. Non-template (plastic tube) techniques are preferred where the tumor volume can be approached from at least two sides and where templates are either not feasible or not essential for accurate positioning of sources. The single needle non-template approach is useful for cancers of lip, nodes, and breast (plastic button) and for cancers of the oral cavity and oropharynx (gold button). The paired needle non-template approach is useful for cancers of the gum, retromolar trigone, and base of tongue (loop technique) and for cancers of the palate (arch technique). Procedures for each technique are described in detail.

  4. Physical characteristics of the Selectron high dose rate intracavitary afterloader

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    Chenery, S.G.A.; Pla, M.; Podgorsak, E.B. (Royal Victoria Hospital, Montreal, Quebec (Canada); McGill Univ., Montreal, Quebec (Canada))


    The physics measurements on a Selectron high dose-rate afterloading cobalt-60 unit are reported. The installation was found to be acceptable from the standpoint of radiation safety and cost effectiveness; hospital bed space was saved as treatment could be on an outpatient basis. A source calibration 4% higher than the value stated by the manufacturer was obtained. Measurement of the ratio of exposure rate in water to that in air confirmed the calibration and the applicability of correction factors for routine clinical dosimetry recommended in the literature.

  5. A new afterloading-applicator for primary brachytherapy of endometrial cancer. First clinical experiences. Neuentwicklung eines Afterloading-Applikators zur primaeren Behandlung des Endometriumkarzinoms. Erster klinischer Erfahrungsbericht

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    Bauer, M.; Schulz-Wendtland, R.; Richard, F. (Freiburg Univ. (Germany). Abt. Gynaekologische Radiologie); Hooft, E. van t' (Nucletron, Leersum (Netherlands))


    Presented is a new afterloading applicator used for primary brachytherapy of endometrial cancer. The advantages: The afterloading applicator holds six afterloading tubes which bundled together in a cover. After the cover is pulled back, the individual tubes expand as a result of the sleeve shape and of the inherent stress of the plastic material used and make direct contact with the endometrium and with the tumor. The applicator is 8 mm in diameter which means that the cervix has to be dilated to Hegar 8 or 9. Radiation planning is done on the basis of orthogonal localisation X-rays or MR. The newly designed applicator can be used for both HDR and LDR afterloading procedures. We have clinical experiences in 42 applications. (orig.).

  6. 10 CFR 35.647 - Additional technical requirements for mobile remote afterloader units. (United States)


    ... on the remote afterloader unit, on the control console, and in the facility; (3) Viewing and intercom... 10 Energy 1 2010-01-01 2010-01-01 false Additional technical requirements for mobile remote... MATERIAL Photon Emitting Remote Afterloader Units, Teletherapy Units, and Gamma Stereotactic...

  7. Remote Afterloading High Dose Rate Brachytherapy AMC EXPERIANCES

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    Park, Su Gyong; Chang, Hye Sook; Choi, Eun Kyong; Yi, Byong Yong [Ulsan University College of Medicine, Seoul (Korea, Republic of)


    Remote afterloading high dose rate brachytherapy(HDRB) is a new technology and needs new biological principle for time and dose schedule. Here, authors attempt to evaluate the technique and clinical outcome in 116 patients, 590 procedures performed at Asan Medical Center for 3 years. From Sep. 1985 to Aug 1992, 471 procedures of intracavitary radiation in 55 patients of cervical cancer and 26 of nasopharyngeal cancer, 79 intraluminal radiation in 12 of esophageal cancer, 11 of endobronchial cancer and 1 Klatskin tumor and 40 interstitial brachytherapy in 4 of breast cancer, 1 sarcoma and 1 urethral cancer were performed. Median follow-up was 7 months with range 1-31 months. All procedures except interstitial were performed under the local anesthesia and they were all well tolerated and completed the planned therapy except 6 patients. 53/58 patients with cervical cancer and 22/26 patients with nasopharynx cancer achieved CR. Among 15 patients with palliative therapy, 80% achieves palliation. We will describe the details of the technique and results in the text. To evaluate biologic effects of HDRB and optimal time/dose/fractionation schedule, we need longer follow-up. But authors feel that HDRB with proper fractionation schedule may yield superior results compared to the low dose rate brachytherapy considering the advantages of HDRB in safety factor for operator, better control of radiation dose and volume and patients comfort over the low dose brachytherapy.

  8. Control strategies for afterload reduction with an artificial vasculature device. (United States)

    Giridharan, Guruprasad A; Cheng, Rolando Chip; Glower, Jacob S; Ewert, Daniel L; Sobieski, Michael A; Slaughter, Mark S; Koenig, Steven C


    Ventricular assist devices (VADs) have been used successfully as a bridge to transplant in heart failure patients by unloading ventricular volume and restoring the circulation. An artificial vasculature device (AVD) is being developed that may better facilitate myocardial recovery than VAD by controlling the afterload experienced by the native heart and controlling the pulsatile energy entering into the arterial system from the device, potentially reconditioning the arterial system properties. The AVD is a valveless, 80 ml blood chamber with a servo-controlled pusher plate connected to the ascending aorta by a vascular graft. Control algorithms for the AVD were developed to maintain any user-defined systemic input impedance (IM) including resistance, elastance, and inertial components. Computer simulation and mock circulation models of the cardiovascular system were used to test the efficacy of two control strategies for the AVD: 1) average impedance position control (AIPC)-to maintain an average value of resistance during left ventricular (LV) systole and 2) instantaneous impedance force feedback (IIFF) and position control (IIPC)-to maintain a desired value or profile of resistance and compliance. Computer simulations and mock loop tests were performed to predict resulting cardiovascular pressures, volumes, flows, and the resistance and compliance experienced by the native LV during ejection for simulated normal, failing, and recovering LV. These results indicate that the LV volume and pressure decreased, and the LV stroke volume increased with decreasing IM, resulting in an increased ejection fraction. Although the AIPC algorithm is more stable and can tolerate higher levels of sensor errors and noise, the IIFF and IIPC control algorithms are better suited to maintain any instantaneous IM or an IM profile. The developed AVD impedance control algorithms may be implemented with current VADs to promote myocardial recovery and facilitate weaning.

  9. Estimation of Filling and Afterload Conditions by Pump Intrinsic Parameters in a Pulsatile Total Artificial Heart. (United States)

    Cuenca-Navalon, Elena; Laumen, Marco; Finocchiaro, Thomas; Steinseifer, Ulrich


    A physiological control algorithm is being developed to ensure an optimal physiological interaction between the ReinHeart total artificial heart (TAH) and the circulatory system. A key factor for that is the long-term, accurate determination of the hemodynamic state of the cardiovascular system. This study presents a method to determine estimation models for predicting hemodynamic parameters (pump chamber filling and afterload) from both left and right cardiovascular circulations. The estimation models are based on linear regression models that correlate filling and afterload values with pump intrinsic parameters derived from measured values of motor current and piston position. Predictions for filling lie in average within 5% from actual values, predictions for systemic afterload (AoPmean , AoPsys ) and mean pulmonary afterload (PAPmean ) lie in average within 9% from actual values. Predictions for systolic pulmonary afterload (PAPsys ) present an average deviation of 14%. The estimation models show satisfactory prediction and confidence intervals and are thus suitable to estimate hemodynamic parameters. This method and derived estimation models are a valuable alternative to implanted sensors and are an essential step for the development of a physiological control algorithm for a fully implantable TAH.

  10. Reduction in radiation exposure to nursing personnel with the use of remote afterloading brachytherapy devices

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    Grigsby, P.W.; Perez, C.A.; Eichling, J.; Purdy, J.; Slessinger, E. (Mallinckrodt Institute of Radiology, St. Louis, MO (USA))


    The radiation exposure to nursing personnel from patients with brachytherapy implants on a large brachytherapy service were reviewed. Exposure to nurses, as determined by TLD monitors, indicates a 7-fold reduction in exposure after the implementation of the use of remote afterloading devices. Quarterly TLD monitor data for six quarters prior to the use of remote afterloading devices demonstrate an average projected annual dose equivalent to the nurses of 152 and 154 mrem (1.5 mSv). After the implementation of the remote afterloading devices, the quarterly TLD monitor data indicate an average dose equivalent per nurse of 23 and 19 mrem (0.2 mSv). This is an 87% reduction in exposure to nurses with the use of these devices (p less than 0.01).

  11. The external work-pressure time integral relationships and the afterload dependence of Frank-Starling mechanism. (United States)

    Sela, Gali; Landesberg, Amir


    The mechanisms underlying the Frank-Starling Law of the heart are elusive and the prevalent notion suggests that it is afterload independent. However, isolated fiber studies reveal that the afterload determines cardiac function through cross-bridge dependent mechanisms. The study explores the roles of the afterload, in situ. The LV was exposed by left-thoracotomy in adult sheep (72.6+/-8.2 kg, n=8). Pressure transducers were inserted into the LV and aorta, a flowmeter was placed around the aortic root, and the LV volume was assessed by sonocrystals. Occluders around the aorta and the inferior vena cava enabled control of the afterload and preload. Different afterloads were imposed by partial aortic occlusions. Transient inferior vena cava occlusions (IVCOs) were preformed whenever the afterload was steady. A highly linear relationship was found between the external work (EW) and pressure time integral (PTI) (R(2)=0.98+/-0.01) during each transient IVCO (n=48). The slope of the EW-PTI relationship (WPTiR) was preload independent since, for any given afterload, the EW and PTI lay on a straight line. Interestingly, the slope of the WPTiR was afterload dependant: The slope was 33.3+/-4.1 mJ/mmHg.s at baselines and decreased by 1.0+/-0.50 mJ/mmHg.s with every 1 mmHg.min/L increase in the peripheral resistance. A unique WPTiR was obtained during both the occlusion and release phases of each IVCO, while two distinct EW-preload or PTI-preload relationships were observed. The novel WPTiR ties the Frank (pressure development) and Starling (EW production) phenomena together. The dependence of the WPTiR on the afterload highlights the adaptive control of the Frank-Starling mechanisms to changes in the afterload.

  12. Mechanical efficiency of stunned myocardium is modulated by increased afterload dependency

    NARCIS (Netherlands)

    D. Fan (Dongsheng); L.K. Soei (Lou Kie); L.M. Sassen; R. Krams (Rob); P.D. Verdouw (Pieter)


    textabstractOxygen consumption (MVO2) of stunned myocardium is relatively high compared to, and poorly correlated with, systolic contractile function. The aim of this study was to investigate whether an increased afterload dependency, induced by the decreased contractility of the stunned myocardium,

  13. A compilation of current regulations, standards and guidelines in remote afterloading brachytherapy

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    Tortorelli, J.P.; Simion, G.P.; Kozlowski, S.D. [Idaho National Engineering Lab., Idaho Falls, ID (United States)


    Over a dozen government and professional organizations in the United States and Europe have issued regulations and guidance concerning quality management in the practice of remote afterloading brachytherapy. Information from the publications of these organizations was collected and collated for this report. This report provides the brachytherapy licensee access to a broad field of quality management information in a single, topically organized document.

  14. [Improvement of gynecologic radium therapy through the afterloading method using cesium 137]. (United States)

    Fournier, D V; Senf, W; Kuttig, H; Kubli, F


    For all centers performing gynecological contact irradiation the use of afterloading techniques is urgently required, since they eliminate any radiation exposure to the personnel. The radio-therapist may position and control the empty applicators still free from radiation withoug haste. This procedure diminishes the occurrence of overdosages and underdosages. The care for the patients is possible without radiation exposure, and the morbidity of contact therapy can be reduced by occasional mobilization of the patient, the applicator without sources remaining at its place. The fully automatic apparatus "Curietron" using cesium-137 sources (0.662 MeV gamma emission, half-life period 26.6 years) with an equivalent source activity (factor 2.6) yields the dose distribution demanded in the gynecologic field which in practice is identical to that of Ra-226 (medium gamma emission 1 MeV, half-life period 1620 years). With similar dose distribution, a biological and therapeutical effect alike to Ra-226 may be expected from Cs-137. In comparison with Ra-226, the following advantages of Cs-137 may be mentioned: Lower half-value thickness of 5.5 mm lead (low expenses for radioprotection), less danger with handling (no emanation of radioactive gases), and lower contamination risks in case of breaking. The measured dose distributions at equivalent source activity and similar geometry of the applicators revealed the possibility with regard of all techniques of gynecologic irradiation utilized in our field of arriving at similar relative and absolute dose distributions by means of the Cs-137 afterloading technique. Whilst short-term afterloading irradiation with highly active sources, their radiobiological effectiveness being not yet ascertained, has to be tested at appropriate scientific centers, it is necessary to demand afterloading techniques with dosages and duration of irradiations approved over decades for all centers of gynecological contact therapy because of radiation

  15. Uncertainty in delivered dose resulting from the distribution of source activities in a Selectron LDR afterloader

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    Ho, A.K.; Castiglione, Robert; Podgorsak, M.B.; Sibata, C.H.; Shin, K.H. (Roswell Park Cancer Inst., Buffalo, NY (United States). Dept. of Radiation Medicine)


    The uncertainty in the delivered dose resulting from the distribution of [sup 137]Cs source activity in a clinical Selectron LDR unit has been studied. A comparison is made of the dose delivered to a point 'A' in an implant with sources of equal activity to the actual dose delivered in the same implant with source activities randomly chosen from the population in the afterloader. (author).

  16. Human factors evaluation of remote afterloading brachytherapy: Human error and critical tasks in remote afterloading brachytherapy and approaches for improved system performance. Volume 1

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    Callan, J.R.; Kelly, R.T.; Quinn, M.L. [Pacific Science and Engineering Group, San Diego, CA (United States)] [and others


    Remote Afterloading Brachytherapy (RAB) is a medical process used in the treatment of cancer. RAB uses a computer-controlled device to remotely insert and remove radioactive sources close to a target (or tumor) in the body. Some RAB problems affecting the radiation dose to the patient have been reported and attributed to human error. To determine the root cause of human error in the RAB system, a human factors team visited 23 RAB treatment sites in the US The team observed RAB treatment planning and delivery, interviewed RAB personnel, and performed walk-throughs, during which staff demonstrated the procedures and practices used in performing RAB tasks. Factors leading to human error in the RAB system were identified. The impact of those factors on the performance of RAB was then evaluated and prioritized in terms of safety significance. Finally, the project identified and evaluated alternative approaches for resolving the safety significant problems related to human error.

  17. SU-E-T-242: Design of a Novel Afterloader Clearance QA Device for Biliary HDR Therapy

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    Mullins, JP; Deufel, CL [Mayo Clinic, Rochester, MN (United States)


    Purpose: Bile duct cancer affects 2–3 thousand people annually in the United States. Radiation therapy has been shown to double median survival, with combined external beam and intraluminal high dose-rate (HDR) brachytherapy being most effective. Endoscopic retrograde cholangiopancreatography (ERCP) biliary HDR, a less-invasive alternative to trans-hepatic brachytherapy, is delivered through a catheter that travels a tortuous path from nose to bile duct, requiring wire drive force and dexterity beyond typical afterloader performance specifications. Thus, specific afterloader quality assurance(QA) is recommended for this procedure. Our aim was to create a device and process for Varisource afterloader clearance QA with objectives that it be quantitative and can monitor afterloader performance over time, compare performance between two distinct afterloaders and potentially Result in a predictive nomogram for patient-specific clearance. Methods: Based on retrospective reconstruction of 20 ERCP patient anatomies, we designed a phantom to test afterloader ability to drive the source wire along an intended treatment path. The ability of the afterloader to fully extend the intended treatment path is a function of number and diameters of turns. We have determined experimentally that relative position of the turns does not impact performance. Results: Both patient and QA paths involve three common turns/loops: a large turn representing the stomach(10.8cm±2.0cm), an elliptical loop representing the duodenum(7.3cm±1.5cmx4.8cm±0.7cm), and a final turn at the end of the bile duct that may be tight for some patient-specific anatomies and absent in others(3.7cm±0.7cm, where present). Our phantom design uses anatomical average turn diameters for the stomach and duodenum then terminates in a turn of quantitatively selectable diameter. The smallest final turn diameter that an afterloader can pass is recorded as the QA parameter. Conclusion: With this device and QA process, we

  18. Intracavitary afterloading boost in anal canal carcinoma. Results, function and quality of life

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    Vordermark, D.; Flentje, M.; Koelbl, O. [Wuerzburg Univ. (Germany). Klinik und Poliklinik fuer Strahlentherapie; Sailer, M. [Wuerzburg Univ. (Germany). Klinik fuer Chirurgie


    Background: First clinical data on a new intracavitary afterloading boost method for anal canal carcinoma is reported. Patients and Methods: 20 consecutive patients (T1 5%, T2 70%, T3 20%, T4 5%; N0 75%, N1 10%, N2 15%; all M0) treated with external beam pelvic radiotherapy (median dose 56 Gy, range 46-64 Gy), simultaneous 5-FU and mitomycin (in 75%) and an intracavitary afterloading boost (one or two fractions of 5 Gy at 5 mm depth) were analyzed after a mean {+-}SD follow-up for living patients of 4.4{+-}2.1 years. Quality of life (QoL) and anorectal manometry parameters were assessed in ten colostomy-free survivors. Results: Overall, recurrence-free and colostomy-free survival at 5 years were 84%, 79% and 69%, respectively. No death was tumorrelated. The only local failure was successfully salvaged by local excision. All three colostomies were performed for toxicity. Resting pressure and maximum squeeze pressure of the anal sphincter were reduced by 51% and 71%, as compared with control subjects, but quality of life was similar compared to healthy volunteers. Conclusion: the described regimen is highly effective but associated with increased toxicity. (orig.) [German] Hintergrund: Erste klinische Ergebnisse einer neuen Methode zur intrakavitaeren Afterloading-Boost-Bestrahlung des Analkanalkarzinoms werden vorgestellt. Patienten und Methoden: 20 in Folge behandelte Patienten (T1 5%, T2 70%, T3 20%, T4 5%, N0 75%, N1 10%, N2 15 %; alle M0) erhielten eine perkutane Bestrahlung (mediane Dosis 56 Gy, 46-64 Gy), simultan 5-FU und Mitomycin (75%) und einen intrakavitaeren Afterloading-Boost (eine oder zwei Fraktionen mit je 5 Gy in 5 mm Tiefe). Der mittlere Nachbeobachtungszeitraum lebender Patienten betrug 4,4{+-}2,1 Jahre. Zehn kolostomiefrei Ueberlebende wurden bezueglich Lebensqualitaet und anorektaler Manometriewerte untersucht. Ergebnisse: Gesamtueberleben, rezidivfreies und kolostomiefreies Ueberleben nach 5 Jahren betrugen 84%, 79% und 69%. Kein Todesfall war

  19. Human factors evaluation of remote afterloading brachytherapy. Volume 2, Function and task analysis

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    Callan, J.R.; Gwynne, J.W. III; Kelly, T.T.; Muckler, F.A. [Pacific Science and Engineering Group, San Diego, CA (United States); Saunders, W.M.; Lepage, R.P.; Chin, E. [University of California San Diego Medical Center, CA (United States). Div. of Radiation Oncology; Schoenfeld, I.; Serig, D.I. [Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Technology


    A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the first phase of the project, which involved an extensive function and task analysis of RAB. This analysis identified the functions and tasks in RAB, made preliminary estimates of the likelihood of human error in each task, and determined the skills needed to perform each RAB task. The findings of the function and task analysis served as the foundation for the remainder of the project, which evaluated four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training and qualifications of RAB staff; and organizational practices and policies. At its completion, the project identified and prioritized areas for recommended NRC and industry attention based on all of the evaluations and analyses.

  20. Calculation of muscle maximal shortening velocity by extrapolation of the force-velocity relationship: afterloaded versus isotonic release contractions. (United States)

    Bullimore, Sharon R; Saunders, Travis J; Herzog, Walter; MacIntosh, Brian R


    The maximal shortening velocity of a muscle (V(max)) provides a link between its macroscopic properties and the underlying biochemical reactions and is altered in some diseases. Two methods that are widely used for determining V(max) are afterloaded and isotonic release contractions. To determine whether these two methods give equivalent results, we calculated V(max) in 9 intact single fibres from the lumbrical muscles of the frog Xenopus laevis (9.5-15.5 °C, stimulation frequency 35-70 Hz). The data were modelled using a 3-state cross-bridge model in which the states were inactive, detached, and attached. Afterloaded contractions gave lower predictions of Vmax than did isotonic release contractions in all 9 fibres (3.20 ± 0.84 versus 4.11 ± 1.08 lengths per second, respectively; means ± SD, p = 0.001) and underestimated unloaded shortening velocity measured with the slack test by an average of 29% (p = 0.001, n = 6). Excellent model predictions could be obtained by assuming that activation is inhibited by shortening. We conclude that under the experimental conditions used in this study, afterloaded and isotonic release contractions do not give equivalent results. When a change in the V(max) measured with afterloaded contractions is observed in diseased muscle, it is important to consider that this may reflect differences in either activation kinetics or cross-bridge cycling rates.

  1. 10 CFR 35.604 - Surveys of patients and human research subjects treated with a remote afterloader unit. (United States)


    ... 10 Energy 1 2010-01-01 2010-01-01 false Surveys of patients and human research subjects treated... Stereotactic Radiosurgery Units § 35.604 Surveys of patients and human research subjects treated with a remote... shall survey the patient or the human research subject and the remote afterloader unit with a...

  2. Dual Endothelin Receptor Blockade Abrogates Right Ventricular Remodeling and Biventricular Fibrosis in Isolated Elevated Right Ventricular Afterload.

    Directory of Open Access Journals (Sweden)

    Eva Amalie Nielsen

    Full Text Available Pulmonary arterial hypertension is usually fatal due to right ventricular failure and is frequently associated with co-existing left ventricular dysfunction. Endothelin-1 is a powerful pro-fibrotic mediator and vasoconstrictor that is elevated in pulmonary arterial hypertension. Endothelin receptor blockers are commonly used as pulmonary vasodilators, however their effect on biventricular injury, remodeling and function, despite elevated isolated right ventricular afterload is unknown.Elevated right ventricular afterload was induced by progressive pulmonary artery banding. Seven rabbits underwent pulmonary artery banding without macitentan; 13 received pulmonary artery banding + macitentan; and 5 did not undergo inflation of the pulmonary artery band (sham-operated controls.Right and left ventricular collagen content was increased with pulmonary artery banding compared to sham-operated controls and ameliorated by macitentan. Right ventricular fibrosis signaling (connective tissue growth factor and endothelin-1 protein levels; extra-cellular matrix remodeling (matrix-metalloproteinases 2 and 9, apoptosis and apoptosis-related peptides (caspases 3 and 8 were increased with pulmonary artery banding compared with sham-operated controls and decreased with macitentan.Isolated right ventricular afterload causes biventricular fibrosis, right ventricular apoptosis and extra cellular matrix remodeling, mediated by up-regulation of endothelin-1 and connective tissue growth factor signaling. These pathological changes are ameliorated by dual endothelin receptor blockade despite persistent elevated right ventricular afterload.

  3. The rate of force generation by the myocardium is not influenced by afterload

    Directory of Open Access Journals (Sweden)

    Fioretto J.R.


    Full Text Available The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt and isolated papillary muscle of rats (dT/dt. Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/kg oxprenolol plus 0.5 mg/kg atropine. A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP. A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H1 and H2 above control values (condition C. After arterial pressure elevations (systolic pressure C: 119 ± 8.1; H1: 142 ± 7.9; H2 166 ± 7.7 mmHg; P<0.01, there were no significant differences in heart rate (C: 125 ± 13.9; H1: 125 ± 13.5; H2: 123 ± 14.1 bpm; P>0.05 or LVEDP (C: 6.2 ± 2.48; H1: 6.3 ± 2.43; H2: 6.1 ± 2.51 mmHg; P>0.05. The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 ± 1,057; H1: 3,112 ± 996; H2: 3,086 ± 980 mmHg/s; P>0.05. In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 ± 13; 75%: 80 ± 13; 50%: 79 ± 11 g mm-2 s-1, P>0.05. The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt


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    Ledee, Dolena; Portman, Michael A.; Kajimoto, Masaki; Isern, Nancy G.; Olson, Aaron


    Background: Subclinical hypothyroidism occurs during aging in humans and mice and may contribute to development of heart failure. Aging also impairs myocardial fatty acid oxidation, causing increased reliance on flux through pyruvate dehydrogenase (PDH) to maintain function. We hypothesize that the metabolic changes in aged hearts make them less tolerant to acutely increased work and that thyroid hormone reverses these defects. Methods: Studies were performed on young (Young, 4-6 months) and aged (Old, 22-24 months) C57/BL6 mice at standard (50 mmHg) and high afterload (80 mmHg). Another aged group received thyroid hormone for 3 weeks (Old-TH, high afterload only). Function was measured in isolated working hearts along with substrate fractional contributions (Fc) to the citric acid cycle (CAC) using perfusate with 13C labeled lactate, pyruvate, glucose and unlabeled palmitate and insulin. Results: Cardiac function was similar between Young and Old mice at standard afterload. Palmitate Fc was reduced but no individual carbohydrate contributions differed. CAC and individual substrate fluxes decreased in aged. At high afterload, -dP/dT was decreased in Old versus Young. Similar to low afterload, palmitate Fc was decreased in Old. Thyroid hormone reversed aging-induced changes in palmitate Fc and flux while significantly improving cardiac function. Conclusion: The aged heart shows diminished ability to increase cardiac work due to substrate limitations, primarily impaired fatty acid oxidation. The heart accommodates slightly by increasing efficiency through oxidation of carbohydrate substrates. Thyroid hormone supplementation in aged mice significantly improves cardiac function potentially through restoration of fatty acid oxidation.

  5. Rectal complication after remote afterloading intracavitary therapy for carcinoma of the uterine cervix

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    Teshima, T.; Chatani, M.; Hata, K.; Inoue, Ta.; Inoue, To.; Suzuki, T.


    From August 1978 through December 1980, 119 patients of previously untreated carcinoma of the uterine cervix were treated using RALS, remote afterloading high dose rate intracavitary therapy at our department. The data from 92 out of 119 patients were available for analysis of rectal complication. The incidence of major rectal complications was only 2% (2/92). Uni- and multivariate analyses were used based on the external criterion variable of rectal complication which included even minor injuries. By using these methods, it was clearly indicated that these factors such as TDF of rectum, Z-coordinate of weighted geometric center (WGC-Z), the dose of whole pelvic irradiation, history of chemotherapy and Treponema pallidum hemoagglutination test (TPHA) were important for occurrence of rectal complication. According to discriminant score, 71 out of 92 cases (77%) could be correctly discriminated.

  6. Five years hospital experience with the Amersham caesium 137 manual afterloading system

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    Bateman, T.J.; Davy, T.J.; Skeggs, D.B.L. (Royal Free Hospital, London (UK))


    The Amersham caesium 137 manual afterloading system for treatment of cancer of the uterine cervix and endometrium has been in use at the Royal Free Hospital for more than five years. The system uses permanently loaded flexible source pencils in combination with standard packs of disposable plastic applicators. Both sources and applicators have proved trouble-free in use. The sources are transported in special containers designed and built at the Royal Free Hospital and are inserted and removed on the ward by nursing staff. A set of sources is used in theatre for rectal and bladder dose measurements when the applicators are inserted. Staff radiation doses are low. The system is mainly used to produce pear-shaped dose distributions similar to those of the Manchester system, but simple cylindrical distributions are possible using symmetrically loaded source pencils.

  7. Contact therapy in the region of pharynx and oral cavity: Afterloading technique, irradiation planning, and results

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    Fritz, P.; Bauer, M.; Fehrentz, D.; Zum Winkel, K.; Weidauer, H.; Singer, R.


    The contact irradiation in the region of pharynx and mouth with an afterloading unit is presented. Twelve patients with recurrent carcinomas of the squamous cell epithelium have been treated. A stable and reproducible positioning of the source probes in the tumor region is made possible by special applicator prostheses which are adapted to the post-operative situation. The irradiation scheme is based on the transformation of the source co-ordinates from the stereoradiographic localization system into the co-ordinate system of the computed tomogram. At least three fixed metal points which are inserted in the applicator prostheses and visualized by stereoradiography as well as by computed tomography serve as mutual reference points for both co-ordinate systems. The source positioning in the tumor region is optimized by CT irradiation planning. Three cases are presented in order to describe the principles of the method. Preliminary results are discussed.

  8. Implication of uterine configuration on dosimetry to point A using the Amersham afterloading system. (United States)

    Vedula, R


    Ninety-four biopsy-proven cases of cervix carcinoma who underwent brachytherapy with the flexible Amersham afterloading system are examined in this study. The uterine configuration showed a wide range with respect to the length, angle of version (indicated by angle alpha) and the degree of right or left shift of the midline at the internal os (indicated by angle beta). The manufacturers of the afterloading system have given certain precalculated dose rates to A which they derived from computer calculations for the various configurations of the system, for a particular loading strength of the Caesium 137 source trains, and for a particular range of angle alpha and beta. The study involves mathematical calculations of point A dose rates using post application radiographs, and a mean value of point A dose rate is derived to compare with other variables. A distortion of the uterus in the form of flexion (as opposed to version), resulting in bending of the uterine tandem is noted in 3 cases. There are 22% of cases with gross degree of retroversion (angle alpha more than 180 degrees) for which the precalculated tables are lacking. The angle beta, however, is in the normal range for all the cases but one. Nineteen cases (20.2%) showed point A dose rates which are beyond the specified dose rates of the manufacturers. Analysis of these 19 cases showed 6 cases with angle alpha more than 180 degrees, eight cases with more than a 10 degrees shift of the uterus to right or left of midline (angle beta) and the rest five cases have fairly normal values of these angles. Analysis of these five cases showed that three of them showed more than 8 CGy/hr difference in dose rates to individual points A right and left. An undue curvature of the uterine tandem to one side in the distal half, with a straight proximal half (near the anterior flange) is noted in these three cases. The angle alpha and beta are normal here since the nearest 2 cm of uterine tandem to the anterior flange is

  9. Alumina ceramic as a biomaterial for use in afterloading radiation catheters for hyperthermia. (United States)

    Ferraro, F T; Salcman, M; Broadwell, R D; Sewchand, W; Neuberth, G


    A major technical challenge to the use of interstitial hyperthermia in malignant brain tumors is the production of a well-defined, uniform hyperthermal field. In theory, A 915-MHz microwave antenna should allow fewer antennas to be used and cause less mechanical brain damage; however, standard radiation afterloading catheters require antennas to be 12 cm long; this is clearly impractical for intracranial use. Since alumina ceramic (Al2O3) catheters permit short microwave antennas (3-5 cm in length) to function properly in neural tissue, it is important to test the biocompatibility of alumina for use in combined interstitial microwave hyperthermia and brachytherapy. A 5-mm length of alumina catheter was implanted into the brains of 15 white rats. The animals were killed at 3, 7, 14, 28, and 56 days. Histological examination revealed only minor mechanical damage and no encapsulation until 1 month; even then, the glial wall was only a few cell layers thick. Five animals received implants and were killed at similar intervals for x-ray microanalysis with the scanning electron microscope. No migration of aluminum into the brain was detected when compared with two control animals that did not receive implants and an alumina blank. Although we measured 50% attenuation of the radiation from iridium-192 sources in alumina catheters as compared with conventional ones, alumina catheters can still be used for interstitial radiation by increasing either the activity of the seeds or the duration of treatment.

  10. Development of computerized dose planning system and applicator for high dose rate remote afterloading irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Choi, T. J. [Keimyung Univ., Taegu (Korea); Kim, S. W. [Fatima Hospital, Taegu (Korea); Kim, O. B.; Lee, H. J.; Won, C. H. [Keimyung Univ., Taegu (Korea); Yoon, S. M. [Dong-a Univ., Pusan (Korea)


    To design and fabricate of the high dose rate source and applicators which are tandem, ovoids and colpostat for OB/Gyn brachytherapy includes the computerized dose planning system. Designed the high dose rate Ir-192 source with nuclide atomic power irradiation and investigated the dose characteristics of fabricated brachysource. We performed the effect of self-absorption and determining the gamma constant and output factor and determined the apparent activity of designed source. he automated computer planning system provided the 2D distribution and 3D includes analysis programs. Created the high dose rate source Ir-192, 10 Ci(370GBq). The effective attenuation factor from the self-absorption and source wall was examined to 0.55 of the activity of bare source and this factor is useful for determination of the apparent activity and gamma constant 4.69 Rcm{sup 2}/mCi-hr. Fabricated the colpostat was investigated the dose distributions of frontal, axial and sagittal plane in intra-cavitary radiation therapy for cervical cancer. The reduce dose at bladder and rectum area was found about 20 % of original dose. The computerized brachytherapy planning system provides the 2-dimensional isodose and 3-D include the dose-volume histogram(DVH) with graphic-user-interface mode. emoted afterloading device was built for experiment of created Ir-192 source with film dosimetry within {+-}1 mm discrepancy. 34 refs., 25 figs., 11 tabs. (Author)

  11. Thyroid hormone reverses aging-induced myocardial fatty acid oxidation defects and improves the response to acutely increased afterload.

    Directory of Open Access Journals (Sweden)

    Dolena Ledee

    Full Text Available BACKGROUND: Subclinical hypothyroidism occurs during aging in humans and mice and may contribute to the development of heart failure. Aging also impairs myocardial fatty acid oxidation, causing increased reliance on flux through pyruvate dehydrogenase (PDH to maintain function. We hypothesize that the metabolic changes in aged hearts make them less tolerant to acutely increased work and that thyroid hormone supplementation reverses these defects. METHODS: Studies were performed on young (Young, 4-6 months and aged (Old, 22-24 months C57/BL6 mice at standard (50 mmHg and high afterload (80 mmHg. Another aged group received thyroid hormone for 3 weeks (Old-TH, high afterload only. Function was measured in isolated working hearts along with substrate fractional contributions (Fc to the citric acid cycle (CAC using perfusate with (13C labeled lactate, pyruvate, glucose and unlabeled palmitate and insulin. RESULTS: Old mice maintained cardiac function under standard workload conditions, despite a marked decrease in unlabeled (presumably palmitate Fc and relatively similar individual carbohydrate contributions. However, old mice exhibited reduced palmitate oxidation with diastolic dysfunction exemplified by lower -dP/dT. Thyroid hormone abrogated the functional and substrate flux abnormalities in aged mice. CONCLUSION: The aged heart shows diminished ability to increase cardiac work due to substrate limitations, primarily impaired fatty acid oxidation. The heart accommodates slightly by increasing efficiency through oxidation of carbohydrate substrates. Thyroid hormone supplementation in aged mice significantly improves cardiac function potentially through restoration of fatty acid oxidation.

  12. New method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. Clinical and hormonal studies

    Energy Technology Data Exchange (ETDEWEB)

    Gronroos, M.; Turunen, T.; Raekallio, J.; Ruotsalinen, P.; Salmi, T. (Turku Univ. (Finland). Dept. of Obstetrics and Gynecology)


    The authors present a new method for the induction of therapeutic amenorrhea: low dose endometrial afterloading irradiation. The problem with this method has been how to inactivate the endometrium while maintaining the physiological function of the ovaries. In 5/29 young patients regular or irregular bleedings occurred after an endometrial dose of 11+-1 Gy. These subjects were given a repeat low dose intrauterine irradiation. Thereafter no bleedings were found in four out of five patients. Two to 9 years after the repeat irradiation the plasma levels of E/sub 1/, E/sub 2/, FSH and LH corresponded closely to those of healthy women in reproductive age in three out of five patients; some high plasma P levels indicated ovulation. In two patients the E/sub 1/, E/sub 2/, and P values were more likely postmenopausal but, on the other hand, FSH and LH values reproductive ones. 19 refs.

  13. Human factors evaluation of remote afterloading brachytherapy. Supporting analyses of human-system interfaces, procedures and practices, training and organizational practices and policies. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Callan, J.R.; Kelly, R.T.; Quinn, M.L. [Pacific Science & Engineering Group, San Diego, CA (United States)] [and others


    A human factors project on the use of nuclear by-product material to treat cancer using remotely operated afterloaders was undertaken by the Nuclear Regulatory Commission. The purpose of the project was to identify factors that contribute to human error in the system for remote afterloading brachytherapy (RAB). This report documents the findings from the second, third, fourth, and fifth phases of the project, which involved detailed analyses of four major aspects of the RAB system linked to human error: human-system interfaces; procedures and practices; training practices and policies; and organizational practices and policies, respectively. Findings based on these analyses provided factual and conceptual support for the final phase of this project, which identified factors leading to human error in RAB. The impact of those factors on RAB performance was then evaluated and prioritized in terms of safety significance, and alternative approaches for resolving safety significant problems were identified and evaluated.

  14. Adaptive right ventricular performance in response to acutely increased afterload in a lamb model of congenital heart disease: evidence for enhanced Anrep effect. (United States)

    Johnson, Rebecca C; Datar, Sanjeev A; Oishi, Peter E; Bennett, Stephen; Maki, Jun; Sun, Christine; Johengen, Michael; He, Youping; Raff, Gary W; Redington, Andrew N; Fineman, Jeffrey R


    Patients with pulmonary hypertension associated with congenital heart disease survive longer with preserved right ventricular (RV) function compared with those with primary pulmonary hypertension. The purpose of this study was to test the hypothesis that superior RV performance can be demonstrated, at baseline and when challenged with increased RV afterload, in lambs with chronic left-to-right cardiac shunts compared with control lambs. A shunt was placed between the pulmonary artery and the aorta in fetal lambs (shunt). RV pressure-volume loops were obtained 4 wk after delivery in shunt and control lambs, before and after increased afterload was applied using pulmonary artery banding (PAB). Baseline stroke volume (8.7 ± 1.8 vs. 15.8 ± 2.7 ml, P = 0.04) and cardiac index (73.0 ± 4.0 vs. 159.2 ± 25.1 ml·min(-1)·kg(-1), P = 0.02) were greater in shunts. After PAB, there was no difference in the change in cardiac index (relative to baseline) between groups; however, heart rate (HR) was greater in controls (168 ± 7.3 vs. 138 ± 6.6 beats/min, P = 0.01), and end-systolic elastance (Ees) was greater in shunts (2.63 vs. 1.31 × baseline, P = 0.02). Control lambs showed decreased mechanical efficiency (71% baseline) compared with shunts. With acute afterload challenge, both controls and shunts maintained cardiac output; however, this was via maladaptive responses in controls, while shunts maintained mechanical efficiency and increased contractility via a proposed enhanced Anrep effect-the second, slow inotropic response in the biphasic ventricular response to increased afterload, a novel finding in the RV. The mechanisms related to these physiological differences may have important therapeutic implications.

  15. Clinical experience of high dose rate brachytherapy using Ir-192 remote afterloading system (microSELECTRON-HDR)

    Energy Technology Data Exchange (ETDEWEB)

    Fukui, Akira; Yamamoto, Koji; Yoshioka, Shinji [Uwajima City Hospital, Ehime (Japan); Kataoka, Masaaki; Fujii, Takashi; Ikezoe, Junpei


    Twenty-one lesions were reviewed of 20 patients who were treated with high-dose-rate brachytherapy using Ir-192 remote afterloading system (microSELECTRON-HDR) between August, 1997 and August, 1998. Esophageal cancer (n=6), lung cancer (n=3), cholangioma (n=3), epipharyngeal cancer (n=2) and uterine cervical cancer (n=2) were treated with intracavitary irradiation. Regional skin recurrence of breast cancer (n=3) was treated with interstitial irradiation, and oral cavity cancer (n=2) was treated with the mold method. Eleven lesions were controlled locally with a short follow-up period. There was no significant complication related to the insertion procedures of the applicator or the tubes without pneumothorax in one patient with lung cancer. So far, this treatment is relatively safe and effective not only for curative therapy for early stage cancer but also for palliative therapy for the advanced cancer. Furthermore, it is very important that medical staffs are kept free from radiation exposure. There is no established treatment protocol in high-dose-rate brachytherapy, therefore, a careful longer follow-up is necessary to clarify the true tumor control rate and the development of the late effect on normal tissue. (author)

  16. Proximal pulmonary arterial obstruction decreases the time constant of the pulmonary circulation and increases right ventricular afterload. (United States)

    Pagnamenta, Alberto; Vanderpool, Rebecca; Brimioulle, Serge; Naeije, Robert


    The time constant of the pulmonary circulation, or product of pulmonary vascular resistance (PVR) and compliance (Ca), called the RC-time, has been reported to remain constant over a wide range of pressures, etiologies of pulmonary hypertension, and treatments. We wondered if increased wave reflection on proximal pulmonary vascular obstruction, like in operable chronic thromboembolic pulmonary hypertension, might also decrease the RC-time and thereby increase pulse pressure and right ventricular afterload. Pulmonary hypertension of variable severity was induced either by proximal obstruction (pulmonary arterial ensnarement) or distal obstruction (microembolism) eight anesthetized dogs. Pulmonary arterial pressures (Ppa) were measured with high-fidelity micromanometer-tipped catheters, and pulmonary flow with transonic technology. Pulmonary ensnarement increased mean Ppa, PVR, and characteristic impedance, decreased Ca and the RC-time (from 0.46 ± 0.07 to 0.30 ± 0.03 s), and increased the oscillatory component of hydraulic load (Wosc/Wtot) from 25 ± 2 to 29 ± 2%. Pulmonary microembolism increased mean Ppa and PVR, with no significant change in Ca and characteristic impedance, increased RC-time from 0.53 ± 0.09 to 0.74 ± 0.05 s, and decreased Wosc/Wtot from 26 ± 2 to 13 ± 2%. Pulse pressure increased more after pulmonary ensnarement than after microembolism. Concomitant measurements with fluid-filled catheters showed the same functional differences between the two types of pulmonary hypertension, with, however, an underestimation of Wosc. We conclude that pulmonary hypertension caused by proximal vs. distal obstruction is associated with a decreased RC-time and increased pulsatile component of right ventricular hydraulic load.

  17. Identifying afterloading PDR and HDR brachytherapy errors using real-time fiber-coupled Al2O3:C dosimetry and a novel statistical error decision criterion

    DEFF Research Database (Denmark)

    Kertzscher, Gustavo; Andersen, Claus Erik; Siebert, Frank-André


    treatment errors, including interchanged pairs of afterloader guide tubes and 2–20mm source displacements, were monitored using a real-time fiber-coupled carbon doped aluminum oxide (Al2O3:C) crystal dosimeter that was positioned in the reconstructed tumor region. The error detection capacity was evaluated...... conditions, and (2) test a new statistical error decision concept based on full uncertainty analysis. Materials and methodsPhantom studies of two gynecological cancer PDR and one prostate cancer HDR patient treatment plans were performed using tandem ring applicators or interstitial needles. Imposed...

  18. Experience in the safety use of a brachytherapy by manual afterloading; Experiencia en el uso seguro de un sistema de braquiterapia por carga diferida manual

    Energy Technology Data Exchange (ETDEWEB)

    Marco Hernandez, Jose M.; Flores Caro, Jorge; Morales Jorge, Leonel [Instituto Nacional de Oncologia y Radiobiologia, La Habana (Cuba). Seccion de Proteccion Radiologica


    Early in the twenty century started in Cuba the use of Radium Brachytherapy for malign neoplasms of the uterine cervix and endometrium, using the Manchester system. This became the main source of personal collective dose and unwanted radiological incidents. In 1989 this method was substituted by Amersham 137 Cs manual afterloading system. The purpose of this work has been to evaluate the impact of the new system in the optimization of this practice in the effective dose and collective effective dose distributions, during ten years, comparing these results of both systems and sources. Monitoring of personnel was done using film bages and recently by means of TLD(Li Fl:Mg). Highest annual exposures with 137 Cs reached only once to 26,2 mSv as result of local rules violation. Technologists, nurses and ward service personnel recorded 14%, 11%, and 29% of the ICRP annual effective dose limit. Thanks to the afterloading system, organisative rules and use of shielded containers, it was achieved a 79% reduction in the collective effective dose. (author)

  19. Methods on Quality Assurance of γ-ray Source of Afterloading Devices%γ射线后装治疗辐射源的质量保证方法

    Institute of Scientific and Technical Information of China (English)

    张庆钊; 曹小龙; 陈梅芬; 黄颂钊; 胡家柱


    获得准确的源强度是表面敷贴放疗剂量与体内治疗剂量计算的基础.在国外,美国医学物理学会( AAPM)制定有直观的放射源校准规程——《在空气中校准》.该方法比较合理、准确、可靠,但是散射修正比较复杂.我国也有国家制定的《192Ir源活度校准规程》,它与AAPM推荐的校准方法的最大区别在于它是在水中校准.事实上,在国内很少有医院对后装192Ir源外观活度进行校准.本文探讨用外照射的小水箱来测量后装放射源活度的方法,测量的结果说明了源活度是基本准确的,符合国家校准规程要求.%Obtaining accurate apparent activity of source is the base stone of the dose calculation of surface applicator brachytherapy and interstitial and intracavitary brachytherapy. There are explicit protocols for source calibration in AAPM that is source calibration in-air. And this way is more reasonable, veracity and reliable, however, the correction of scatter from all surfaces in the room is complicate. There is a protocol of calibrations for apparent activity of afterloading iridium-192 source in our country. The most different is that it is calibrated in-water phantom, there are little hospitals calibrating the apparent activity of afterloading iridium-192 according to this protocol .The paper discussed the method of measuring afterloading radiation source activity with small water phantom. The result demonstrates the apparent activity of afterloading iridium-192 source is veracity.

  20. Results of high intensity afterloading irradiation with 192 iridium in the therapy of genital tumors in women under different dose rates, fractionations and total doses in comparison with conventional radium contact irradiation. Ergebnisse der High-Intensity-Afterloadingbestrahlung mit 192 Iridium in der Therapie von Genitaltumoren der Frau unter verschiedenen Dosisleistungen, Fraktionierungen und Gesamtdosen im Vergleich mit konventioneller Radiumkontaktbestrahlung

    Energy Technology Data Exchange (ETDEWEB)

    Giers, G.


    In comparison to conventional radium therapy are to be evaluated the results of the high intensity afterloading technique with the help of the parameters survial rate and complication rate. Thereby were included in the examination 4 documentations of results (collum, cervix stump, corpus and vaginal carcinoma) with altogether 742 patients with 2806 single irradiations and an evaluation of the therapy after several modifications of the therapy schemes. The 5-year survival rate was in the case of collum carcinoma: 68.4%, cervix stump: 50%, corpus carcinoma: 76%, and vaginal carcinoma: 66.6%. The corresponding 3-year survival rates were: 74.2%, 80%, 84% and 70% with primary irradiation. Only with cervix stump carcinoma were the values for post-operative irradiation. The description of the irradiation results showed, that with the changing of the fractionation mode and the dose level in collum and corpus carcinoma the irreversible complications as an expression of the success of a new therapy were reduced. The for now best suited therapy schema (fractionation and dosing) are described. (TRV).

  1. 聚焦解决模式联合耳穴贴压法对绝经宫颈癌患者后装腔内放疗后焦虑及疼痛的影响%Effect of solution-focused approach combined with auricular acupressure on anxiety and pain of patients with postmenopausal cervical cancer during afterloading brachytherapy

    Institute of Scientific and Technical Information of China (English)

    张曦霞; 张兰凤; 刘敏杰


    Objective To observe the effect of solution-focused approach combined with auricular acupressure on relieving the anxiety and pain of patients with postmenopausal cervical cancer during afterloading brachytherapy .Methods One hundred and twenty patients who treated with uterine cavity for the first time were randomly divided into the observation group ( n =60 ) and the control group ( n =60 ) .The control group received the conventional nursing , and the observation group received the solution-focused approach nursing combined with auricular acupressure on the basis of the conventional nursing .The self-rating anxiety scale ( SAS ) was used before the intervention and one week after the intervention ( once again before afterloading brachytherapy ) , and the score of pain and the satisfaction of patients were evaluated during the afterloading brachytherapy .Results No difference was not found in the score of SAS before the intervention between two groups (P>0.05).The score of SAS was (42.3 ±44.46) in the observation group one week after the intervention , and was significantly lower than ( 49 .76 ±4 .57 ) in the control group , and the difference was statistically significant (t=-9.00, P<0.05).The cases of the grade Ⅰof pain were 15 cases (25%), gradeⅡwere 42 cases (70%), grade Ⅲ were 2 cases (3.33%), grade Ⅳ were 1 case (1.67%) in the observation group during operation , and were respectively 2 cases (3.33%), 28 cases (46.67%), 27 cases (45%), 3 cases (5%) in the control group, and the degree of pain in the observation group during operation was significantly better than the control group , and the difference was statistically significant (Z=-5.74, P<0.001).The satisfaction of patients in the observation group during operation (4.89 ±0.10) was better than (3.87 ±0.51) in the control group and the difference was statistically significant (t =15.21, P<0.05). Conclusions The solution-focused approach combined with auricular acupressure during afterloading

  2. Pituitary-ovarian hormones after low-dose endometrial afterloading irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Groenroos, M.; Kauppila, O.; Pulkkinen, M.; Turunen, S.; Salmi, T.; Raekallio, J. (Turku Univ. (Finland). Dept. of Obstetrics and Gynecology)


    Low-dose endometrial after loading irradiation was used in 19 mentally retarded women for the induction of therapeutic amenorrhea. They were divided into two groups on the basis of age: 13 young patients (mean age 17 years, range 13-26 years) and six patients of middle age (mean age 42 years, range 34-44 years). In the young patients, during the 10 month follow-up period, the plasma E/sub 2/ levels did not decrease. However, the FSH concentration increased. Later on, 2-9 years after treatment, the E/sub 2/ levels were significantly higher than those of healthy postmenopausal women and did not differ from the values of healthy women in the six to seven days of the menstrual cycle. At that time the FSH and LH levels were similar to reference values in reproductive age. The E/sub 2//E/sub 1/ ratio was significantly higher than that of healthy women in the six to seven days of the cycle and that of postmenopausal women. Most of the menstrual cycles were anovulatory but some ovulatory also occurred. The testosterone concentrations did not differ from reference values. The ovaries of the middle age patients were more sensitive to irradiation than those of the younger patients. 7 refs.

  3. Real-time in vivo dosimetry and error detection during afterloading brachytherapy

    DEFF Research Database (Denmark)

    Kertzscher Schwencke, Gustavo Adolfo Vladimir

    error scenarios, in order to quantify the error detection sensitivity of the real-time point dosimetry system used by means of a statistical error detection concept that incorporated a full uncertainty analysis. The limiting effects of the dependence on the a priori reconstruction of the dosimeter...... sources, even small discrepancies of the planned source position may result in largely modified dose distributions that could lead to an insufficient dose to the tumor and/or increased doses to OARs. One way to monitor the integrity of a BT treatment delivery and to detect potential treatment errors......, is to perform real-time in vivo dosimetry (IVD) inside the target region during the treatment. That way, an independent and patient specific verification of the agreement between delivered and planned treatments can be performed. If a treatment error is detected, modifications of the treatment parameters...

  4. 10 CFR 35.690 - Training for use of remote afterloader units, teletherapy units, and gamma stereotactic... (United States)


    ...) Radiation physics and instrumentation; (B) Radiation protection; (C) Mathematics pertaining to the use and... an authorized user or authorized medical physicist, as appropriate, who is authorized for the...

  5. Effects of Endovascular Brachytherapy with 192Ir Afterloading System on Expression of Type Ⅰ Collagen after Angioplasty

    Institute of Scientific and Technical Information of China (English)

    向定成; 杨传红; 候友贤; 龚志华; 易绍东; 邱建


    Objectives To investi-gate the effect and mechanism of endovascularbrachytherapy with 192Ir on expression of type Ⅰ collagen, metalloproteinases - 1 (MMP - 1) and the tissueinhibitor (TIMP- 1 ) after angioplasty. MethodsRestenotic model of domestic microswine was em-ployed and the iliac arteries were randomized to radi-ation group ( n = 12), which were treated with 20 ~ 25Gy of 192Ir, and non - radiation group ( n = 36) afterangioplasty. The target vessels were harvested in theend of 3 months and 6 months after angioplasty. Im-munohistochemistry and in situ hybridization were usedto detect proteins of type Ⅰ collagen, MMP-1 andTIMP- 1, and mRNA expression of type Ⅰ collagen.Results The protein and mRNA of type Ⅰ collagen,the ratios of TIMP-1/MMP-1 were significantlylower iu radiation group than in non- radiation group( P < 0.05 or 0.01 ). The peak of transcription of typeⅠ collagen mRNA was at 6 months and 3 months in non-radiation group and radiation group respectively.Conclusions Endovascular brachytherapy with192Ir might modify the metabolism of extracellular ma-trix after angioplasty by inhibiting the synthesis of typeⅠ collagen and the activities of MMP - 1 and TIMP - 1.

  6. Shielding evaluation of a medical linear accelerator vault in preparation for installing a high-dose rate 252Cf remote afterloader. (United States)

    Melhus, C S; Rivard, M J; Kurkomelis, J; Liddle, C B; Massé, F X


    In support of the effort to begin high-dose rate 252Cf brachytherapy treatments at Tufts-New England Medical Center, the shielding capabilities of a clinical accelerator vault against the neutron and photon emissions from a 1.124 mg 252Cf source were examined. Outside the clinical accelerator vault, the fast neutron dose equivalent rate was below the lower limit of detection of a CR-39 etched track detector and below 0.14 +/- 0.02 muSv h(-1) with a proportional counter, which is consistent, within the uncertainties, with natural background. The photon dose equivalent rate was also measured to be below background levels (0.1 muSv h(-1)) using an ionisation chamber and an optically stimulated luminescence dosemeter. A Monte Carlo simulation of neutron transport through the accelerator vault was performed to validate measured values and determine the thermal-energy to low-energy neutron component. Monte Carlo results showed that the dose equivalent rate from fast neutrons was reduced by a factor of 100,000 after attenuation through the vault wall, and the thermal-energy neutron dose equivalent rate would be an additional factor of 1000 below that of the fast neutrons. Based on these findings, the shielding installed in this facility is sufficient for the use of at least 5.0 mg of 252Cf.


    NARCIS (Netherlands)



    It has been well documented that different therapeutic strategies, including angiotensin-converting enzyme (ACE) inhibitors, nonsteroidal anti-inflammatory drugs, and dietary protein restriction, lower urinary protein excretion in patients with diabetic and non-diabetic nephropathy. Experimental evi

  8. 体外加腔内照射治疗中晚期宫颈癌的远期疗效分析%Long-term results of cervix cancer (stage Ⅱ, stage Ⅲ) with external irradiation combination with afterloading radiotherapy

    Institute of Scientific and Technical Information of China (English)

    张小红; 许新华; 杨雅琴; 尚友兰; 蔡鑫; 薛峰



  9. 宫颈癌低剂量率后装腔内放射治疗的远期疗效%Low-dose rate intracavitary afterloading radiotherapy for cancer of uterine cervix

    Institute of Scientific and Technical Information of China (English)

    张新; 王伊洵; 王慧明


    目的评价Gynatron低剂量率后装腔内治疗机的疗效.方法总结1980年4月~1986年6月间,应用Gynatron后装机配合60Co治疗机进行根治性放疗的136例宫颈癌,并与镭疗及高剂量率腔内后装治疗进行比较分析.结果除5例失访外,全部患者随访超过15年,随访率96.3%(131/136).Ⅱ、Ⅲ期的10年生存率分别为83.9%和43.2%.总10年生存率为63.5%.放射性直肠炎发生率为12.5 %(17/136),放射性膀胱炎发生率9.6% (13/136).结论 Gynatron低剂量率后装腔内治疗系统虽然有一定局限性,但仍可获得较满意的疗效;其治疗并发症患者可以接受,放射性直肠炎、放射性膀胱炎发生率高于镭疗,低于高剂量率腔内后装放疗.

  10. Design Intervention and Radiological Protection Test for Remote After-Loading Brachytherapy Item in a Hospital%某医院近距离后装治疗项目设计干预与防护效果验证

    Institute of Scientific and Technical Information of China (English)

    李秀芹; 赵进沛; 吴欣; 刘士敏; 李华军


    目的 干预近距离后装机室设计与运行模式,验证放射防护效果,降低射线项目对医务人员和患者健康的影响.方法 根据相关标准和资料,对某医院后装治疗机室设计布局进行干预,利用多功能辐射仪和热释光剂量计对相关工作场所进行环境辐射监测,对后装机室防护效果进行验证.对后装机项目的运行进行调研和指导.结果 该项目经设计干预后防护效果符合标准要求.结论 在放射卫生单位严格按照国家有关法规标准设计建设大型医用射线项目的同时,加强设计干预效果验证与放射防护指导,对于消除项目隐患、节省建设经费,提高放射诊疗质量和保证安全防护具有深远的意义.

  11. 联合放疗后前列腺MRI与组织病理学的相关性%MRT der Prostata nach kombinierter Radiotherapie (Afterloading und perkutan):Histopathologische Korrelation

    Institute of Scientific and Technical Information of China (English)


    目的:研究局限性前列腺癌联合放疗(后装和经皮)后前列腺的MR成像和组织学表现的关系。评价MRI对病人随访的价值。   方法:对联合放疗结束后6~24个月的23例病人行1.5T的MRI检查。用轴位和冠状位T2W序列和静脉给Gd-DTPA前后作轴位T1W序列行前列腺成像。所有病人在MR检查后行四点或六点活组织检查。3例确有肿瘤残存的病人行补救性前列腺切除术。比较、分析MR片和活检结果或大块切片。   结果:T2W成像中纤维性变的外周呈低信号,肿瘤组织呈高信号。可显示直径在1cm以下的实性肿瘤。而多病灶的弥散性肿瘤残存则不显影。对比剂增强的T1W成像不提供更多信息。探测肿瘤残存的准确性为74%。   结论:联合放射后组织病理学的变化与T2W的MRI成像结果一致。MRI检查不可以替代常规的活检,只应在随访中PSA值上升时才使用,以判断局部手术的可行性。MRI检查这些病人的价值有待于进一步研究。 摘自Fortschr Rntgenstr 2000,172∶680-685

  12. Tumor hypoxia - A confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model

    NARCIS (Netherlands)

    van den Berg, AP; van Geel, CAJF; van Hooije, CMC; van der Kleij, AJ; Visser, AG


    Purpose: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. Methods and Materials: Afterloading catheters (4) Here implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij rats

  13. 1251 seed calibration using afterloading equipment Seed Selectron. Practical solution to meet the recommendations of the AAPM; Calibracion de semillas de {sup 1}25I usando el equipo de carga difereida SeedSelectron. Solucion practica para cumplir las recomendaciones de la AAPM

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Calatayud, J.; Richart, J.; Perez-Garcia, J.; Guirado, D.; Ballester, F.; Rodriguez, S.; Santos, M.; Depiaggio, M.; Carmona, V.; Lliso, F.; Camacho, C.; Pujades, M. C.


    Seed Selectron is a system used in the after loader permanent implant brachytherapy seeds 1-125 interstitial prostate. Two aspects are critical when you can meet the recommendations of the AAPM: a practical difficulty to check the quantity of seed required, and the great uncertainty of all measured diodes. The purpose of this paper is to present a practical solution that has been adopted to implement the recommendations of the AAPM.

  14. The effect of adrenaline and high Ca2+ on the mechanical performance and oxygen consumption of the isolated perfused trout (Oncorhynchus mykiss) heart

    DEFF Research Database (Denmark)

    Rytter, Dorte; Gesser, Hans


    In heart muscle from mammals, catecholamines frequently evoke an oxygen waste and reduce efficiency. It was examined if this also applies to fish in which heart muscle activity is often restricted by oxygen availability. In the isolated perfused heart from rainbow trout, adrenaline (0.5 micro......M) increased power output by approximately 97%, when afterload was adjusted to maximum both before and after adrenaline addition, and by approximately 68%, when afterload remained at the maximum obtained before adrenaline addition. Oxygen consumption was enhanced by a similar amount (approximately 70%) in both...... situations. Hence, efficiency, i.e. power output/oxygen consumption, increased significantly from 25 to 30% for the heart always exposed to maximal afterload, whereas it stayed unchanged at 24% for the heart exposed to control afterload only. Adrenaline increases the Ca2+ activity participating in activation...

  15. Mechanical ventilation-induced intrathoracic pressure distribution and heart-lung interactions*

    NARCIS (Netherlands)

    Lansdorp, B.; Hofhuizen, C.M.; Lavieren, M. van; Swieten, H.A. van; Lemson, J.; Putten, M.J.A.M. van; Hoeven, J.G. van der; Pickkers, P.


    OBJECTIVE: Mechanical ventilation causes cyclic changes in the heart's preload and afterload, thereby influencing the circulation. However, our understanding of the exact physiology of this cardiopulmonary interaction is limited. We aimed to thoroughly determine airway pressure distribution, how thi

  16. Analysis of optimal design configurations for a multiple disk centrifugal blood pump. (United States)

    Miller, G E; Fink, R


    A multiple disk centrifugal pump was analyzed as a blood pump for use in cardiac assistance or as a bridge to transplant device. The original configuration consisted of 6 parallel disks with 0.016 inch spacing between disks. This pump suffered from a degradation of flow with increasing afterload. A study was conducted to analyze flow performance as a function of afterload, preload, and motor speed. Configurations were examined including 4, 5, and 6 disks each with spacings of 0.15, 0.20, and 0.25 inches. Flow rates were examined for variations in afterload from 60-130 mm Hg, in preload from 0-20 mm Hg and for motor speeds of 1,250, 1,500, and 1,750 rpm. Analyses of afterload effects were intended to determine those configurations that produced less flow degradation with increasing afterload. Analyses of motor speed effects were intended to determine any configurations that produced greater flow increases with increasing motor speed. A hemolysis study was also performed. Both plasma free hemoglobin and the index of hemolysis were compared to data reported for other centrifugal blood flow devices. Results indicated that a 5 disk configuration with a 0.15 inch spacing produced optimal flow results with minimal degradation at higher afterloads. No optimal configuration based upon motor speed was indicated. Preload effects on pump performance were minimal. Hemolysis results indicated minimal blood damage with levels below those of many other centrifugal blood pump designs.

  17. [The thickness/radius ratio of the left ventricle in aortic stenosis. Prognostic and therapeutic implications]. (United States)

    Guadalajara, J F; Martínez, C; Huerta, D


    Using two-D echocardiography and cardiac catheterization we studied the performance of left ventricle in severe aortic stenosis with normal ventricular function (10 patients), and with heart failure (11 patients). With appropriate hypertrophy increased ventricular function, is found resulting in systolic wall stress normalization. When hypertrophic mechanism is unable to normalize the systolic wall stress; afterload increases with ensuing heart failure (inadequate hypertrophy). Surgical treatment in those cases reduces the afterload and increases de ventricular function. Normalization of systolic wall stress in patients with severe aortic stenosis and heart failure means irreversible myocardial damage.

  18. [New challenges to the treatment of cervical intraepithelial neoplasia]. (United States)

    Sun, J H


    Due to the progress of intracavitary afterloading technology and dosage of brachytherapy, a similar dose distribution as that of cervical conization can be achieved and can be applied to the treatment of cervical intraepithelial neoplasia (CIN), it is called "afterloading conization" . Being adjusted the radioactive source movement and weight, low exposure doses to the ovary, endometrium and vagina can be assured. So a high quality of life after treatment could be maintained and overcomes the shortcomings of cervical conization and hysterectomy, such as anesthesia, bleeding, over or insufficient treatment, early ovarian ageing and operative complications.

  19. The haemodynamic effects of nifedipine, verapamil and diltiazem in patients with coronary artery disease. A review

    NARCIS (Netherlands)

    A.L. Soward; G.L.J. Vanhaleweyk; P.W.J.C. Serruys (Patrick)


    textabstractOf the 3 most widely used calcium antagonists--nifedipine, verapamil and diltiazem--nifedipine is the most potent arterial vasodilator. Increases in cardiac output and coronary blood flow following nifedipine administration result in part from the afterload reduction. Reflex adrenergic s

  20. 10 CFR 35.605 - Installation, maintenance, adjustment, and repair. (United States)


    ... 10 Energy 1 2010-01-01 2010-01-01 false Installation, maintenance, adjustment, and repair. 35.605... Installation, maintenance, adjustment, and repair. (a) Only a person specifically licensed by the Commission or an Agreement State shall install, maintain, adjust, or repair a remote afterloader unit,...

  1. A LabVIEW model incorporating an open-loop arterial impedance and a closed-loop circulatory system. (United States)

    Cole, R T; Lucas, C L; Cascio, W E; Johnson, T A


    While numerous computer models exist for the circulatory system, many are limited in scope, contain unwanted features or incorporate complex components specific to unique experimental situations. Our purpose was to develop a basic, yet multifaceted, computer model of the left heart and systemic circulation in LabVIEW having universal appeal without sacrificing crucial physiologic features. The program we developed employs Windkessel-type impedance models in several open-loop configurations and a closed-loop model coupling a lumped impedance and ventricular pressure source. The open-loop impedance models demonstrate afterload effects on arbitrary aortic pressure/flow inputs. The closed-loop model catalogs the major circulatory waveforms with changes in afterload, preload, and left heart properties. Our model provides an avenue for expanding the use of the ventricular equations through closed-loop coupling that includes a basic coronary circuit. Tested values used for the afterload components and the effects of afterload parameter changes on various waveforms are consistent with published data. We conclude that this model offers the ability to alter several circulatory factors and digitally catalog the most salient features of the pressure/flow waveforms employing a user-friendly platform. These features make the model a useful instructional tool for students as well as a simple experimental tool for cardiovascular research.

  2. Cardiopulmonary interactions during mechanical ventilation in critically ill patients

    NARCIS (Netherlands)

    T.G.V. Cherpanath (Thomas); W.K. Lagrand (Wim); M.J. Schultz (Marcus); A.B.J. Groeneveld (Johan)


    textabstractCardiopulmonary interactions induced by mechan-ical ventilation are complex and only partly understood. Ap-plied tidal volumes and/or airway pressures largely mediate changes in right ventricular preload and afterload. Effects on left ventricular function are mostly secondary to changes

  3. Effects of arteriovenous fistulas on cardiac oxygen supply and demand

    NARCIS (Netherlands)

    Bos, W.J.W.; Zietse, R.; Wesseling, K.H.; Westerhof, N.


    Background. Arteriovenous (AV) fistulas used for hemodialysis access may affect cardiac load by increasing the preload while decreasing the afterload. In dogs, AV fistulas have also been shown to affect coronary perfusion negatively. We investigated the net effect of AV fistulas on cardiac oxygen su

  4. Monte Carlo derivation of AAPM TG-43 dosimetric parameters for GZP6 Co-60 HDR sources. (United States)

    Tabrizi, Sanaz Hariri; Asl, Alireza Kamali; Azma, Zohreh


    Cobalt 60 source is generally available on high dose rate (HDR) afterloading equipment especially for treatment of gynecological lesions. The GZP6 remote afterloader (Nuclear Power Institute of China) utilizes (60)Co sources for treatment of intracavitary and intraluminal malignancies. In this study, the AAPM TG-43 dosimetric parameters of three sources in GZP6 system have been studied using MCNP4C Monte Carlo (MC) code; and the results are compared with other available (60)Co HDR sources. The presented parameters consist of air kerma strength, dose rate constant, radial dose function and anisotropy function. They show less than 1% uncertainty. The TG-43 based dosimetry data can be used not only to validate the dedicated treatment planning software (TPS), but also to introduce new complementary software to enhance the system performance in gynecological treatments.

  5. Reduction of regurgitation in aortic insufficiency by inhibition of the renin/angiotensin conversion enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Reske, S.N.; Heck, I.; Mattern, H.


    The effect of captopril-mediated afterload reduction on regurgitation was investigated in 10 patients with aortic insufficiency. Regurgitation was quantitated by the regurgitation fraction and the relation of regurgitant volume to end-diastolic volume, which were derived from gated radionuclide ventriculography. 19 patients with coronary artery disease and no evidence of valvular heart disease served as controls. In patients with coronary artery disease no significant reguration was found. In patients with aortic regurgitation the blood concentration of angiotensin I increased whereas that of angiotensin II decreased significantly after captopril-medication; thus, the conversion of angiotensin I to II was reduced to about 50% of the control value. Whereas blood pressure and heart rate did not change significantly, the regurgitation fraction and the normalized regurgitant volume were significantly reduced. The ejection fraction remained essentially unchanged. These findings suggest a favorable influence of captopril-induced afterload reduction on hemodynamics in aortic regurgitation.

  6. Assessment of the Frank-Starling relationship by two-dimensional echocardiography. (United States)

    Zipprich, D A; Owen, C H; Lewis, C W; Gall, S A; Davis, J W; Kisslo, J A; Glower, D D


    The Frank-Starling relationship between left ventricular stroke work and end-diastolic minor-axis cross-sectional area was evaluated as a load-insensitive measure of inotropic state by two-dimensional echocardiography in 10 conscious dogs. Stroke work was calculated as the product of systolic change in cross-sectional area and either (1) beat-to-beat mean arterial pressure or (2) initial systolic blood pressure. Both Frank-Starling relationships were highly linear during preload variation (mean r = 0.96), sensitive to the inotropic state (slope increase with calcium 51% +/- 43% and 62% +/- 53%, respectively), and insensitive to afterload (r < 0.4, slope or x intercept versus afterload). Thus the Frank-Starling relationships derived from two-dimensional echocardiographic images and peripheral arterial pressure may be a useful and practical means of assessing inotropic state with minimally invasive measurements.

  7. Echocardiographic quantification of systolic function during atrial fibrillation

    DEFF Research Database (Denmark)

    Olsen, Flemming Javier; Jørgensen, Peter Godsk; Dons, Maria;


    It is often difficult to provide an exact echocardiographic measure of left ventricular systolic function in patients with atrial fibrillation, partly because of the varying cycle length affecting pre and afterload and partly because of the increased heart rate often accompanying this arrhythmia....... We sought to elucidate two points: whether it would be possible to correct for the cyclic variance in systolic output, and if global longitudinal strain is preferable to the left ventricular ejection fraction at evaluating systolic function during atrial fibrillation....

  8. Postoperative myocardial performance during glucose-induced hypophosphatemia

    DEFF Research Database (Denmark)

    Rasmussen, A; Buus, S; Hessov, I


    Long-lasting hypophosphatemia was previously found to diminish myocardial performance. The present study aimed to elucidate if postoperative glucose-induced hypophosphatemia is of importance for myocardial performance. Sixteen patients undergoing elective colonic or rectal surgery were given 100 g....... As the preload (central venous pressure) and the afterload (arterial pressure) similarly were unchanged by the glucose infusion, glucose-induced hypophosphatemia following elective surgery was judged to lack importance for the myocardial performance....

  9. Pulmonary Edema


    Tanser, Paul H.


    The physician who deals with pulmonary edema from a pathophysiologic basis will seldom make a diagnostic or therapeutic error. Recent additions to preload and afterload therapy have greatly helped in the emergency and ambulatory treatment of pulmonary edema due to left heart failure. Careful follow-up and patient self-monitoring are the most effective means of reducing hospitalization of chronic heart failure patients.

  10. Anaesthetic management of peripartum cardiomyopathy for emergency caesarean section: A case report

    Directory of Open Access Journals (Sweden)

    Teena Bansal


    Full Text Available Peripartum cardiomyopathy is a rare but life threatening condition. Anaesthetic management of a patient with peripartum cardiomyopathy for caesarean section is a major challenge for anaesthesiologist. Timely diagnosis of the condition, institution of appropriate medication regimen, a carefully chosen anaesthetic technique and vigilant perioperative monitoring are essential for optimizing outcome in these patients. The goals of anaesthetic management include maintenance of optimal ventricular preload and afterload while avoiding any anaesthesia induced myocardial depression.

  11. In situ cardiac perfusion reveals interspecific variation of intraventricular flow separation in reptiles. (United States)

    Joyce, William; Axelsson, Michael; Altimiras, Jordi; Wang, Tobias


    The ventricles of non-crocodilian reptiles are incompletely divided and provide an opportunity for mixing of oxygen-poor blood and oxygen-rich blood (intracardiac shunting). However, both cardiac morphology and in vivo shunting patterns exhibit considerable interspecific variation within reptiles. In the present study, we develop an in situ double-perfused heart approach to characterise the propensity and capacity for shunting in five reptile species: the turtle Trachemys scripta, the rock python Python sebae, the yellow anaconda Eunectes notaeus, the varanid lizard Varanus exanthematicus and the bearded dragon Pogona vitticeps To simulate changes in vascular bed resistance, pulmonary and systemic afterloads were independently manipulated and changes in blood flow distribution amongst the central outflow tracts were monitored. As previously demonstrated in Burmese pythons, rock pythons and varanid lizards exhibited pronounced intraventricular flow separation. As pulmonary or systemic afterload was raised, flow in the respective circulation decreased. However, flow in the other circulation, where afterload was constant, remained stable. This correlates with the convergent evolution of intraventricular pressure separation and the large intraventricular muscular ridge, which compartmentalises the ventricle, in these species. Conversely, in the three other species, the pulmonary and systemic flows were strongly mutually dependent, such that the decrease in pulmonary flow in response to elevated pulmonary afterload resulted in redistribution of perfusate to the systemic circuit (and vice versa). Thus, in these species, the muscular ridge appeared labile and blood could readily transverse the intraventricular cava. We conclude that relatively minor structural differences between non-crocodilian reptiles result in the fundamental changes in cardiac function. Further, our study emphasises that functionally similar intracardiac flow separation evolved independently in

  12. Mechanochemotransduction during cardiomyocyte contraction is mediated by localized nitric oxide signaling. (United States)

    Jian, Zhong; Han, Huilan; Zhang, Tieqiao; Puglisi, Jose; Izu, Leighton T; Shaw, John A; Onofiok, Ekama; Erickson, Jeffery R; Chen, Yi-Je; Horvath, Balazs; Shimkunas, Rafael; Xiao, Wenwu; Li, Yuanpei; Pan, Tingrui; Chan, James; Banyasz, Tamas; Tardiff, Jil C; Chiamvimonvat, Nipavan; Bers, Donald M; Lam, Kit S; Chen-Izu, Ye


    Cardiomyocytes contract against a mechanical load during each heartbeat, and excessive mechanical stress leads to heart diseases. Using a cell-in-gel system that imposes an afterload during cardiomyocyte contraction, we found that nitric oxide synthase (NOS) was involved in transducing mechanical load to alter Ca(2+) dynamics. In mouse ventricular myocytes, afterload increased the systolic Ca(2+) transient, which enhanced contractility to counter mechanical load but also caused spontaneous Ca(2+) sparks during diastole that could be arrhythmogenic. The increases in the Ca(2+) transient and sparks were attributable to increased ryanodine receptor (RyR) sensitivity because the amount of Ca2(+) in the sarcoplasmic reticulum load was unchanged. Either pharmacological inhibition or genetic deletion of nNOS (or NOS1), but not of eNOS (or NOS3), prevented afterload-induced Ca2(+) sparks. This differential effect may arise from localized NO signaling, arising from the proximity of nNOS to RyR, as determined by super-resolution imaging. Ca(2+)-calmodulin-dependent protein kinase II (CaMKII) and nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2) also contributed to afterload-induced Ca(2+) sparks. Cardiomyocytes from a mouse model of familial hypertrophic cardiomyopathy exhibited enhanced mechanotransduction and frequent arrhythmogenic Ca(2+) sparks. Inhibiting nNOS and CaMKII, but not NOX2, in cardiomyocytes from this model eliminated the Ca2(+) sparks, suggesting mechanotransduction activated nNOS and CaMKII independently from NOX2. Thus, our data identify nNOS, CaMKII, and NOX2 as key mediators in mechanochemotransduction during cardiac contraction, which provides new therapeutic targets for treating mechanical stress-induced Ca(2+) dysregulation, arrhythmias, and cardiomyopathy.

  13. Pulmonary manifestations of heartworm disease. (United States)

    Calvert, C A; Rawlings, C A


    The clinical signs associated with heartworm disease are the result of changes in the pulmonary arterial system. These clinical signs are the result of either pulmonary hypertension or lung parenchymal disease associated with vascular changes. An increase in pulmonary arterial pressure produces an increase in right ventricular afterload, which may lead to exercise intolerance, syncope, and right-sided congestive heart failure. Coughing, dyspnea, and hemoptysis are the results of pulmonary parenchymal disease.

  14. Asymmetric left ventricular hypertrophy associated with morbid obesity mimicking familial hypertrophic cardiomyopathy. (United States)

    Wong, Raymond Ching-Chiew; Tan, Kong Bing


    Asymmetric septal hypertrophy with systolic anterior motion of the mitral valve is frequently a phenotypic, but not pathognomonic, expression of genetic hypertrophic cardiomyopathy (HCM) with or without obstruction. It can, however, be associated nonspecifically with other forms of increased left ventricular (LV) afterload. We herein report the case of a young man with obesity cardiomyopathy and heart failure who presented with asymmetric septal hypertrophy and marked LV hypertrophy, and endomyocardial biopsy ruled out genetic HCM.

  15. Simulation of the Frank-Starling Law of the Heart


    Samo Ribarič; Marjan Kordaš


    We developed a lumped parameter, computer-based model of an equivalent electronic circuit for a one-atrium one-ventricle (frog) heart attached to a vascular circuit, to simulate a basic concept of cardiovascular physiology, the Frank-Starling Law of the Heart. A series of simulations was performed, to observe changes in cardiovascular variables (e.g., arterial pressure, ventricular volume, and valve flows) if either preload or afterload was increased. The simulated data agreed qualitatively, ...

  16. Hemodynamic response to treatment of iron deficiency anemia in pulmonary arterial hypertension: longitudinal insights from an implantable hemodynamic monitor. (United States)

    Mehmood, Muddassir; Agarwal, Richa; Raina, Amresh; Correa-Jaque, Priscilla; Benza, Raymond L


    Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) were measured on a daily basis, and parameters of right ventricular (RV) performance and afterload were calculated. At the time of IHM implant, the patient had functional class III symptoms, was receiving triple-drug therapy, and had normal hemoglobin levels. Four months after implant, and with further optimization of prostacyclin therapy, she had improvement in her symptoms. However, shortly thereafter, while the patient was receiving stable drug therapy, her case regressed with worsening symptoms, and the patient received a new diagnosis of iron deficiency anemia. Oral iron supplementation resulted in normalization of hemoglobin levels and improvement in the patient's iron profile. A gradual and sustained reduction in pulmonary pressures was noted after initiation of oral iron accompanied by increased RV performance and favorable reduction in RV afterload. The patient had significant symptomatic improvement. Iron deficiency is an underappreciated yet easily treatable risk factor in PAH. Use of IHM in this case longitudinally illustrates the optimization of pulmonary hemodynamics and RV afterload in tandem with clinical improvement achieved by a simple therapy.

  17. Hemodynamic response to treatment of iron deficiency anemia in pulmonary arterial hypertension: longitudinal insights from an implantable hemodynamic monitor (United States)


    Abstract Despite new therapeutic options, pulmonary arterial hypertension (PAH) remains a progressive disease associated with substantial morbidity and mortality. As such, additional strategies for monitoring and adjunctive management of this disease are important. A 59-year-old woman with scleroderma-associated PAH received an implantable hemodynamic monitor (IHM) as part of a research protocol at our institution. Pulmonary artery pressures, heart rate, and cardiac output (sensor-based algorithm) were measured on a daily basis, and parameters of right ventricular (RV) performance and afterload were calculated. At the time of IHM implant, the patient had functional class III symptoms, was receiving triple-drug therapy, and had normal hemoglobin levels. Four months after implant, and with further optimization of prostacyclin therapy, she had improvement in her symptoms. However, shortly thereafter, while the patient was receiving stable drug therapy, her case regressed with worsening symptoms, and the patient received a new diagnosis of iron deficiency anemia. Oral iron supplementation resulted in normalization of hemoglobin levels and improvement in the patient’s iron profile. A gradual and sustained reduction in pulmonary pressures was noted after initiation of oral iron accompanied by increased RV performance and favorable reduction in RV afterload. The patient had significant symptomatic improvement. Iron deficiency is an underappreciated yet easily treatable risk factor in PAH. Use of IHM in this case longitudinally illustrates the optimization of pulmonary hemodynamics and RV afterload in tandem with clinical improvement achieved by a simple therapy. PMID:28090307

  18. External beam and intracavitary irradiation of the esophagus carcinomas. Perkutan-endokavitaere Strahlenbehandlung der Oesophaguskarzinome

    Energy Technology Data Exchange (ETDEWEB)

    Fritz, P.; Schraube, P.; Oberle, J.; Wannenmacher, M. (Heidelberg Univ. (Germany). Radiologische Klinik); Friedl, P. (Heidelberg Univ. (Germany). Chirurgische Klinik)


    In a prospective, non-randomized study 43 patients with inoperable oesophageal carcinoma were treated with a combined therapy of external and intracavitary irradiation according to the Heidelberg protocol adjusted to tumor stage, general condition and age. The proportion of external beam to afterloading doses was 2/3:1/3. The reference doses were between 50 and 75 Gy. Intracavitary radiotherapy was carried out with a HDR-afterloading device in single doses of 5 Gy. In a median follow-up of 23 months 46% had a complete remission and 42% had a partial remission. Within ten months 17 patients (39.5%) showed local tumor progression or recurrence. Presently the estimated median survival time of the whole collective is eleven months. The median survival was significantly influenced by achievement of complete remission (17.7 months in comparison to 8.7 months by missing complete remission). After completion of therapy 90% had sufficient oral nutrition. During long-term follow-up in 44% of the cases repeated measures had to be taken to eliminate initial or recurrent dysphagia. Almost all postradiogenic stenoses were caused by tumor progression. Radiogenic side-effects caused by HDR-afterloading boosts, exceeding the acceptance, were not found. The combined therapy reduces the period of hospitalisation and has the same palliative effects as an exclusively external radiotherapy. (orig.).

  19. Feasibility of combined operation and perioperative intensity-modulated brachytherapy of advanced/recurrent malignancies involving the skull base

    Energy Technology Data Exchange (ETDEWEB)

    Strege, R.J.; Eichmann, T.; Mehdorn, H.M. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Neurosurgery; Kovacs, G.; Niehoff, P. [University Hospital Schleswig-Holstein, Kiel (Germany). Interdisciplinary Brachytherapy Center; Maune, S. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Otolaryngology; Holland, D. [University Hospital Schleswig-Holstein, Kiel (Germany). Dept. of Ophthalmology


    Purpose: To assess the technical feasibility and toxicity of combined operation and perioperative intensity-modulated fractionated interstitial brachytherapy (IMBT) in advanced-stage malignancies involving the skull base with the goal of preserving the patients' senses of sight. Patients and Methods: This series consisted of 18 consecutive cases: ten patients with paranasal sinus carcinomas, five with sarcomas, two with primitive neuroectodermal tumors (PNETs), and one with parotid gland carcinoma. After, in most cases, subtotal surgical resection (R1-R2: carried out so that the patients' senses of sight were preserved), two to twelve (mean five) afterloading plastic tubes were placed into the tumor bed. IMBT was performed with an iridium-192 stepping source in pulsed-dose-rate/high-dose-rate (PDR/HDR) afterloading technique. The total IMBT dose, ranging from 10 to 30 Gy, was administered in a fractionated manner (3-5 Gy/day, 5 days/week). Results: Perioperative fractionated IMBT was performed in 15 out of 18 patients and was well tolerated. Complications that partially prevented or delayed IMBT in some cases included cerebrospinal fluid leakage (twice), meningitis (twice), frontal brain syndrome (twice), afterloading tube displacement (twice), seizure (once), and general morbidity (once). No surgery- or radiation-induced injuries to the cranial nerves or eyes occurred. Median survival times were 33 months after diagnosis and 16 months after combined operation and IMBT. Conclusion: Perioperative fractionated IMBT after extensive but vision-preserving tumor resection seems to be a safe and well-tolerated treatment of advanced/recurrent malignancies involving the skull base. These preliminary state suggest that combined operation and perioperative fractionated IMBT is a palliative therapeutic option in the management of fatal malignancies involving the base of the skull, a strategy which leaves the patients' visual acuity intact. (orig.)

  20. Recovery of the Frank-Starling mechanism by coenzyme Q10 in patients with load-induced contractility depression. (United States)

    Oda, T


    Load-induced contractility depression, in which supernormal left ventricular ejection fraction and contractility at rest decrease by added afterload, is most often found in children with mitral valve prolapse who have symptoms. Patients have high ventricular end-diastolic pressure at rest, which is further increased by afterload challenge. The Frank-Starling mechanism may be maximally mobilized with high preload even at rest to compensate for the intrinsically depressed inotropic state. Therefore, preload reserve may be easily exhausted due to afterload addition. We aimed to determine left ventricular end-diastolic fiber length, stroke work, and contractility before and during handgrip by echocardiograms to obtain evidence for the Frank-Starling mechanism in patients and controls, including patients treated with coenzyme Q10. The subjects were divided into four groups, each consisting of 30 children aged 6-16 years: group 1, normals; group 2, patients; group 3, the same patients as in group 2 after coenzyme Q10 therapy; and group 4, patients with asymptomatic mitral valve prolapse. Baseline values and percentage increases in systolic blood pressure, heart rate, and left ventricular wall stress showed no differences among the groups. Only in group 2 were the percentage increase in ejection fraction, fiber shortening velocity, contractility, and end-diastolic dimension strongly negative, despite supernormal baseline levels. In other groups, these were significantly positive, without intergroup differences. We conclude that in the heart with load-induced contractility depression, the Frank-Starling mechanism deviates from normal. The normal Frank-Starling mechanism was recovered due to coenzyme Q10, which may improve disturbed bioenergetic function at the molecular level.

  1. Acute right ventricular dysfunction: real-time management with echocardiography. (United States)

    Krishnan, Sundar; Schmidt, Gregory A


    In critically ill patients, the right ventricle is susceptible to dysfunction due to increased afterload, decreased contractility, or alterations in preload. With the increased use of point-of-care ultrasonography and a decline in the use of pulmonary artery catheters, echocardiography can be the ideal tool for evaluation and to guide hemodynamic and respiratory therapy. We review the epidemiology of right ventricular failure in critically ill patients; echocardiographic parameters for evaluating the right ventricle; and the impact of mechanical ventilation, fluid therapy, and vasoactive infusions on the right ventricle. Finally, we summarize the principles of management in the context of right ventricular dysfunction and provide recommendations for echocardiography-guided management.

  2. Cardiovascular issues in respiratory care. (United States)

    Pinsky, Michael R


    The hemodynamic effects of ventilation are complex but can be grouped under four clinically relevant concepts. First, spontaneous ventilation is exercise, and critically ill patients may not withstand the increased work of breathing. Initiation of mechanical ventilatory support will improve oxygen delivery to the remainder of the body by decreasing oxygen consumption. To the extent that mixed venous oxygen also increases, Pao(2) will increase without any improvement in gas exchange. Similarly, weaning from mechanical ventilatory support is a cardiovascular stress test. Patients who fail to wean also manifest cardiovascular insufficiency during the failed weaning attempts. Improving cardiovascular reserve or supplementing support with inotropic therapy may allow patients to wean from mechanical ventilation. Second, changes in lung volume alter autonomic tone and pulmonary vascular resistance (PVR), and at high lung volumes compress the heart in the cardiac fossa. Hyperinflation increases PVR and pulmonary artery pressure, impeding right ventricular ejection. Decreases in lung volume induce alveolar collapse and hypoxia, stimulating an increased pulmonary vasomotor tone by the process of hypoxic pulmonary vasoconstriction. Recruitment maneuvers, positive end-expiratory pressure, and continuous positive airway pressure may reverse hypoxic pulmonary vasoconstriction and reduce pulmonary artery pressure. Third, spontaneous inspiration and spontaneous inspiratory efforts decrease intrathoracic pressure (ITP). Since diaphragmatic descent increases intra-abdominal pressure, these combined effects cause right atrial pressure inside the thorax to decrease but venous pressure in the abdomen to increase, markedly increasing the pressure gradient for systemic venous return. Furthermore, the greater the decrease in ITP, the greater the increase in left ventricular (LV) afterload for a constant arterial pressure. Mechanical ventilation, by abolishing the negative swings in ITP

  3. [Study of ventricular function by means of echocardiographic quantification of the thickness/radius (h/r) ratio of the left ventricle in healthy subjects]. (United States)

    Guadalajara, J F; Martínez, C; Gutiérrez, E; Zamora, C; Huerta, D


    We studied 72 healthy subjects; 31 of them were adults and 41 children. By means of two-dimensional echocardiography we obtained a short axis view at the papillary muscle level of the ratio of the thickness (h) of the ventricular wall and the radius (r) of the cavity. We analysed ventricular performance determinants (pre-load, after-load and contractility). This non-invasive method gives information similar to pressure-volume curves. Thus, we propose it for the study of left ventricular overloads.

  4. Phentolamine as a treatment for poor mixing in transposition of the great arteries with adequate intraatrial communication. (United States)

    Galal, M O; El-Naggar, W I; Sharfi, M H


    Patients with transposition of the great arteries often show poor mixing for different reasons, even after adequate balloon atrial septostomy. We present a patient with such a lesion whose clinical status improved dramatically after phentolamine was applied. We believe this improvement is due to reduction in afterload caused by the alpha(2) blocker and also possibly as a response to a presumptive effect of the drug on the diastolic function of the right ventricle, allowing more left-to-right shunt across the atrial septal defect. Both phenomena can improve cardiac output in such a situation.

  5. Rupture of Right Ventricular Free Wall Following Ventricular Septal Rupture in Takotsubo Cardiomyopathy with Right Ventricular Involvement. (United States)

    Sung, June Min; Hong, Sung Jin; Chung, In Hyun; Lee, Hye Young; Lee, Jae Hoon; Kim, Hyun Jung; Byun, Young Sup; Kim, Byung Ok; Rhee, Kun Joo


    Most patients diagnosed with takotsubo cardiomyopathies are expected to almost completely recover, and their prognosis is excellent. However, complications can occur in the acute phase. We present a case of a woman with takotsubo cardiomyopathy with right ventricular involvement who developed a rupture of the right ventricular free wall following ventricular septal rupture, as a consequence of an acute increase in right ventricular afterload by left-to-right shunt. Our case report illustrates that takotsubo cardiomyopathy can be life threatening in the acute phase. Ventricular septal rupture in biventricular takotsubo cardiomyopathy may be a harbinger of cardiac tamponade by right ventricular rupture.

  6. Five years' experience with the gold button technique for intraoral interstitial implants with iridium-192 seeds. (United States)

    Kumar, P P; Henschke, U K


    To simulate crossing of the ends in standard removable interstitial implants, we used the loop technique for intraoral tumors when treating them with afterloading interstitial removable implants. Because of technical problems, we changed to a straight tube method with heavy end-loading to compensate for the uncrossed ends. High doses to the normal mucosa close to heavy end-loading is reduced 2.5 times by the use of gold buttons in place of standard stainless steel buttons, thus decreasing unnecessary mucosal reactions and morbidity.

  7. Centrifugal pump inlet pressure site affects measurement. (United States)

    Augustin, Simon; Horton, Alison; Butt, Warwick; Bennett, Martin; Horton, Stephen


    During extracorporeal life support (ECLS), blood is exposed to a myriad of unphysiological factors that can affect outcome. One aspect of this is the sub-atmospheric pressure generated by the ECLS pump and imparted to blood elements along the pump inlet line. This pressure can be measured on the inlet line close to the pump head by adding a connector, or at the venous cannula connection site. We compared the two measurement sites located at both points; between the venous cannula-inlet tubing and inlet tubing-pump, with a range of cannulae and flows. We also investigated the effects on inlet pressure from pump afterload and increasing inlet tubing length.

  8. Radiation sources for engineering and medicine. 2. rev. and enl. ed.; Strahlungsquellen fuer Technik und Medizin

    Energy Technology Data Exchange (ETDEWEB)

    Krieger, Hanno


    The book on radiation sources for engineering and medicine includes the following issues: Part I: Particle accelerators: review on radiation sources; fundamentals on particle accelerators and radiation optics; electron an ion sources, the X-ray tube; DC accelerators; high-frequency generators; hollow wave guides and cavity resonators; linear accelerators; medical electron linear accelerators; ring accelerators; synchrotron radiation and storage rings. Part II: Nuclear reactors and neutron sources: nuclear reactors; neutron sources and their applications. Part III: Radionuclides and their application: radionuclide production; radionuclides in medicine; cobalt radiation facilities for medicine; afterloading facilities for medicine; technical applications for radionuclides. Part IV: Attachments: tables; literature.

  9. High dose brachytherapy in pediatric oncology; Braquiterapia com alta taxa de dose em oncologia pediatrica

    Energy Technology Data Exchange (ETDEWEB)

    Ferrigno, Robson; Codjaian, Osanna Esther; Novaes, Paulo Eduardo R.S.; Trippe, Nivaldo [Fundacao Antonio Prudente, Sao Paulo, SP (Brazil). Hospital A.C. Camargo. Dept. de Radioterapia


    Brachytherapy is a kind of radiotherapy that has been used in the multidisciplinary approach of some pediatric tumors, such as soft tissue sarcomas of the extremities, head and neck and urogenital tract. Recent technological advances in this area lead to development of computerized high dose rate remote afterloading brachytherapy. This type of treatment has some advantages compared to low dose rate brachytherapy traditionally used. This article describes not only the characteristics and advantages of this kind of treatment, but also the preliminary results of the first seven children treated with high dose rate at the Hospital A.C.Camargo. (author) 10 refs., 8 figs.

  10. New perspectives of studying gastrointestinal muscle function

    Institute of Scientific and Technical Information of China (English)

    Hans Gregersen; Donghua Liao


    The motor function of the gastrointestinal tract has primarily been studied using manometry and radiography,though more indirect tests have also been applied. Manometry and radiography do not provide detailed information about the muscle properties as can be assessed from studies of muscle properties in muscle strips in vitro. In recent years a technique based on impedance planimetric mEasurement of pressure-cross-sectional area relations in a distending bag has proven to provide more detailed information about the muscle function in vivo. This review shows examples of new muscle function analysis such as length-tension diagrams, forcevelocity curves and preload-afterload diagrams.

  11. Precision of RL/OSL medical dosimetry with fiber-coupled Al2O3:C: Influence of readout delay and temperature variations

    DEFF Research Database (Denmark)

    Andersen, Claus Erik; Morgenthaler Edmund, Jens; Damkjær, Sidsel Marie Skov


    Carbon-doped aluminum oxide (Al2O3:C) crystals attached to 15 m optical fiber cables can be used for online in vivo dosimetry during, for example, remotely afterloaded brachytherapy. Radioluminescence (RL) is generated spontaneously in Al2O3:C during irradiation, and this scintillator-like signal....... These coefficients account for changes in RL and OSL signals with changes in temperature during irradiation and stimulation. The work was primarily based on a set of automated laboratory measurements carried out using 50 kV X-rays (0–3 Gy) with delays in the range of 10–3600 s and temperatures in the range of 10...

  12. Precision of RL/OSL medical dosimetry with fiber-coupled Al2O3:C: Influence of readout delay and temperature variations

    DEFF Research Database (Denmark)

    Andersen, C.E.; Edmund, J.M.; Damkjaer, S.M.S.


    Carbon-doped aluminum oxide (Al2O3:C) crystals attached to 15 m optical fiber cables can be used for online in vivo dosimetry during, for example, remotely afterloaded brachytherapy. Radioluminescence (RL) is generated spontaneously in Al2O3:C during irradiation, and this scintillator-like signal....... These coefficients account for changes in RI and OSL signals with changes in temperature during irradiation and stimulation. The work was primarily based on a set of automated laboratory measurements carried out using 50 kV X-rays (0-3 Gy) with delays in the range of 10-3600 s and temperatures in the range of 10...

  13. Sarns centrifugal pump for repair of thoracic aortic injury: case reports. (United States)

    Walls, J T; Curtis, J J; Boley, T


    A new centrifugal pump (Sarns), originally designed for ventricular assist, was successfully used in two patients during repair of traumatic pseudoaneurysm of the descending thoracic aorta. The distal thoracic aorta was perfused without heparinization to avoid spinal cord and visceral ischemia, reduce afterload on the heart, and avoid clamp injury to the aorta. Distal mean aortic pressure was maintained above 50 mm Hg with a mean pump flow of 1.75 liter/minute. Proposed structural advantages of the Sarns centrifugal pump for perfusion of the distal thoracic aorta without heparin are resistance to thrombus formation, air embolus, and hemolysis.

  14. Matching models of left ventricle and systemic artery

    Institute of Scientific and Technical Information of China (English)

    柳兆荣; 吴驰


    To reveal how the matching models of the left ventricle and its afterload affect the pressure and flow in the aortic root, the differences between the measured pressure and flow waveforms and those determined by three kinds of matching model were compared. The results showed that, compared with the results by both matching models 1 and 2, the pressure and flow waveforms determined by matching model 3 established in this work were in the closest agreement with the corresponding experimental waveforms, therefore indicating that matching model 3 was a matching model that closely and rationally characterized the match between the left ventricle and the systemic artery.

  15. Saline volume expansion and cardiovascular physiology: novel observations, old explanations, and new questions. (United States)

    Robotham, James L


    In a clinical investigation, Kumar and coworkers reported the hemodynamic events that accompany plasma volume expansion over 3 hours in healthy adult volunteers, and found that increases in stroke volume (SV) may be related to increases in left ventricular (LV)/right ventricular (RV) end-diastolic volume, as they expected, but also to decreases in LV/RV end-systolic volume. The latter finding suggests increased contractility and/or decreased afterload, which do not fit with their perception that clinicians ascribe increases in SV to increases in end-diastolic volume based on Starling's work. Increased ejection fraction and decreased vascular resistances were also observed. The same authors recently reported novel data suggesting that reduced blood viscosity may account for the observed reduction in vascular resistances with saline volume expansion. However, the variances in preload and afterload, along with uncertainty in estimates of contractility, substantially limit their ability to define a primary mechanism to explain decreases in LV end-systolic volume. A focus on using ejection fraction to evaluate the integrated performance of the cardiovascular system is provided to broaden this analytic perspective. Sagawa and colleagues described an approach to estimate the relationship, under clinical conditions, between ventricular and arterial bed elastances (i.e. maximal ventricular systolic elastance [Emax] and maximal arterial systolic elastance [Ea]), reflecting ventricular-arterial coupling. I used the mean data provided in one of the reports from Kumar and coworkers to calculate that LV Emax decreased from 1.09 to 0.96 mmHg/ml with saline volume expansion, while Ea decreased from 1.1 to 0.97 mmHg/ml and the SV increased (i.e. the increase in mean SV was associated with a decrease in mean afterload while the mean contractility decreased). The results reported by Kumar and coworkers invite further studies in normal and critically ill patients during acute saline

  16. Fetal cardiovascular physiology. (United States)

    Rychik, J


    The cardiovascular system of the fetus is physiologically different than the adult, mature system. Unique characteristics of the myocardium and specific channels of blood flow differentitate the physiology of the fetus from the newborn. Conditions of increased preload and afterload in the fetus, such as sacrococcygeal teratoma and twin-twin transfusion syndrome, result in unique and complex pathophysiological states. Echocardiography has improved our understanding of human fetal cadiovasvular physiology in the normal and diseased states, and has expanded our capability to more effectively treat these disease processes.

  17. Temperature measurement errors with thermocouples inside 27 MHz current source interstitial hyperthermia applicators. (United States)

    Kaatee, R S; Crezee, H; Visser, A G


    The multielectrode current source (MECS) interstitial hyperthermia (IHT) system uses thermocouple thermometry. To obtain a homogeneous temperature distribution and to limit the number of traumas due to the implanted catheters, most catheters are used for both heating and thermometry. Implications of temperature measurement inside applicators are discussed. In particular, the impact of self-heating of both the applicator and the afterloading catheter were investigated. A one-dimensional cylindrical model was used to compute the difference between the temperature rise inside the applicators (deltaTin) and in the tissue just outside the afterloading catheter (deltaTout) as a function of power absorption in the afterloading catheter, self-heating of the applicator and the effective thermal conductivity of the surrounding tissue. Furthermore, the relative artefact (ERR), i.e. (deltaTin - deltaTout)/deltaTin, was measured in a muscle equivalent agar phantom at different positions in a dual-electrode applicator and for different catheter materials. A method to estimate the tissue temperature by power-off temperature decay measurement inside the applicator was investigated. Using clinical dual-electrode applicators in standard brachytherapy catheters in a muscle-equivalent phantom, deltaTin is typically twice as high as deltaTout. The main reason for this difference is self-heating of the thin feeder wires in the centre of the applicator. The measurement error caused by energy absorption in the afterloading catheter is small, i.e. even for materials with a high dielectric loss factor it is less than 5%. About 5 s after power has been switched off, Tin in the electrodes represents the maximum tissue temperature just before power-off. This delay time (t(delay)) and ERR are independent of Tin. However, they do depend on the thermal properties of the tissue. Therefore, ERR and t(delay) and their stability in perfused tissues have to be investigated to enable a reliable

  18. Management of Sepsis in Patients with Pulmonary Arterial Hypertension in the Intensive Care Unit. (United States)

    Tartavoulle, Todd M


    Pulmonary arterial hypertension is a lethal condition, and the management of sepsis in patients with pulmonary arterial hypertension is challenging. As the disease progresses, the right ventricle is susceptible to failure due to a high pulmonary vascular resistance. The limited ability of the right ventricle to increase cardiac output in septic shock makes it difficult to deliver oxygen to the organ and tissues. Intravascular volume replacement and vasoactive drugs should only be considered after a thorough assessment. Priorities of care include improving cardiac output and oxygen delivery by optimizing preload, reducing afterload, and improving contractility.

  19. The application of Geant4 simulation code for brachytherapy treatment

    CERN Document Server

    Agostinelli, S; Garelli, S; Paoli, G; Nieminen, P; Pia, M G


    Brachytherapy is a radiotherapeutic modality that makes use of radionuclides to deliver a high radiation dose to a well-defined volume while sparing surrounding healthy structures. At the National Institute for Cancer Research of Genova a High Dose Rate remote afterloading system provides Ir(192) endocavitary brachytherapy treatments. We studied the possibility to use the Geant4 Monte Carlo simulation toolkit in brachytherapy for calculation of complex physical parameters, not directly available by experiment al measurements, used in treatment planning dose deposition models.

  20. Cardiovascular anatomy and physiology of the fetus, neonate, infant, child, and adolescent. (United States)

    Alyn, I B; Baker, L K


    Practicing cardiovascular nurses are aware that significant differences exist in the cardiac anatomy and physiology of children and adults. Generally, the younger the child the greater these differences are. The cellular anatomy and physiology are markedly different in the fetus, neonate, and infant. As development progresses, cardiac function begins to more closely approximate that of an adult. This article describes the anatomical and physiologic development of the fetus, neonate, infant, child, and adolescent. The developmental differences in preload, afterload, contractility, and heart rate are summarized.

  1. Khan's the physics of radiation therapy

    CERN Document Server

    Khan, Faiz M


    Expand your understanding of the physics and practical clinical applications of advanced radiation therapy technologies with Khan's The Physics of Radiation Therapy, 5th edition, the book that set the standard in the field. This classic full-color text helps the entire radiation therapy team-radiation oncologists, medical physicists, dosimetrists, and radiation therapists-develop a thorough understanding of 3D conformal radiotherapy (3D-CRT), stereotactic radiosurgery (SRS), high dose-rate remote afterloaders (HDR), intensity modulated radiation therapy (IMRT), image-guided radiation therapy (

  2. Effects of a single terlipressin administration on cardiac function and perfusion in cirrhosis

    DEFF Research Database (Denmark)

    Krag, Aleksander; Bendtsen, Flemming; Mortensen, Christian


    BACKGROUND: The vasoconstrictor terlipressin is widely used in the treatment of the hepatorenal syndrome and variceal bleeding. However, terlipressin may compromise cardiac function and induce ischemia. AIM: Therefore, we aimed to assess the effects of terlipressin on cardiac function and perfusion...... with nonrefractory ascites, both at baseline and after terlipressin treatment. The decrease in the left ventricular wall thickening and wall motion correlated with the Child--Pugh score, r=-0.59, P=0.005 and r=-0.48, P=0.03. CONCLUSION: In advanced cirrhosis, the increase in afterload and EDV after terlipressin...

  3. Emergency mitral valve replacement for acute severe mitral regurgitation following balloon mitral valvotomy: Pathophysiology of hemodynamic collapse and peri-operative management issues

    Directory of Open Access Journals (Sweden)

    Praveen Reddy Bayya


    Full Text Available Severe mitral regurgitation (MR following balloon mitral valvotomy (BMV needing emergent mitral valve replacement is a rare complication. The unrelieved mitral stenosis is compounded by severe MR leading to acute rise in pulmonary hypertension and right ventricular afterload, decreased coronary perfusion, ischemia and right ventricular failure. Associated septal shift and falling left ventricular preload leads to a vicious cycle of myocardial ischemia and hemodynamic collapse and needs to be addressed emergently before the onset of end organ damage. In this report, we describe the pathophysiology of hemodynamic collapse and peri-operative management issues in a case of mitral valve replacement for acute severe MR following BMV.

  4. Dynamic changes of left ventricular performance and left atrial volume induced by the mueller maneuver in healthy young adults and implications for obstructive sleep apnea, atrial fibrillation, and heart failure. (United States)

    Orban, Marek; Bruce, Charles J; Pressman, Gregg S; Leinveber, Pavel; Romero-Corral, Abel; Korinek, Josef; Konecny, Tomas; Villarraga, Hector R; Kara, Tomas; Caples, Sean M; Somers, Virend K


    Using the Mueller maneuver (MM) to simulate obstructive sleep apnea (OSA), our aim was to investigate acute changes in left-sided cardiac morphologic characteristics and function which might develop with apneas occurring during sleep. Strong evidence supports a relation between OSA and both atrial fibrillation and heart failure. However, acute effects of airway obstruction on cardiac structure and function have not been well defined. In addition, it is unclear how OSA might contribute to the development of atrial fibrillation and heart failure. Echocardiography was used in healthy young adults to measure various parameters of cardiac structure and function. Subjects were studied at baseline, during, and immediately after performance of the MM and after a 10-minute recovery. Continuous heart rate, blood pressure, and pulse oximetry measurements were made. During the MM, left atrial (LA) volume index markedly decreased. Left ventricular (LV) end-systolic dimension increased in association with a decrease in LV ejection fraction. On release of the maneuver, there was a compensatory increase in blood flow to the left side of the heart, with stroke volume, ejection fraction, and cardiac output exceeding baseline. After 10 minutes of recovery, all parameters returned to baseline. In conclusion, sudden imposition of severe negative intrathoracic pressure led to an abrupt decrease in LA volume and a decrease in LV systolic performance. These changes reflected an increase in LV afterload. Repeated swings in afterload burden and chamber volumes may have implications for the future development of atrial fibrillation and heart failure.

  5. Characterization of HDR Ir-192 source for 3D planning system

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, Gabriel P.; Yoriyaz, Helio; Antunes, Paula C.G.; Siqueira, Paulo T.D., E-mail: gabriel.fonseca@usp.b, E-mail: hyoriyaz@ipen.b, E-mail: ptsiquei@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Rubo, Rodrigo [Universidade de Sao Paulo (HC/FMUSP), Sao Paulo, SP (Brazil). Hospital das Clinicas. Servico de Radioterapia; Minamisawa, Renato A., E-mail: renato.minamisawa@psi.c [Paul Scherrer Institut (PSI), Villigen (Switzerland); Ferreira, Louise A. [Universidade Estadual de Maringa (UEM), PR (Brazil). Fac. de Medicina


    Brachytherapy treatment involves surgical or cavitary insertion of radioactive sources for diseases treatments, such as: lung, gynecologic or prostate cancer. This technique has great ability to administer high doses to the tumor, with adjacent normal tissue preservation equal or better than external beam radiation therapy. Several innovations have been incorporated in this treatment technique, such as, 3D treatment planning system and computer guided sources. In detriment to scientific advances there are no protocols that relate dose with tumor volume, organs or A point, established by ICRU38 and used to prescribe dose in treatment planning system. Several international studies, like as EMBRACE, the multicentre international study, has been trying to correlate the dose volume using 3D planning systems and medical images, as those obtained by CT or MRI, to establish treatment protocols. With the objective of analyzing the 3D dose distribution, a micro Selectron-HDR remote afterloading device for high dose-rate (HDR) was characterized in the present work. Through the data provided by the manufacturer the source was simulated, using the MCNP5 code to calculate American Association of Physicists in Medicine Task Group No. 43 report (AAPM TG43) specified parameters. The simulations have shown great agreement when compared to the ONCENTRA planning system results and those provided by literature. The micro Selectron-HDR remote afterloading device will be utilized to simulate 3D dose distribution through CT images processed by an auxiliary software which process DICOM images. (author)

  6. Hemodynamic Performance of a Novel Right Ventricular Assist Device (PERKAT) (United States)

    Schulze, P. Christian; Ferrari, Markus W.


    Acute right ventricular failure (RVF) is an increasing clinical problem and a life-threatening condition. Right ventricular assist devices represent a reasonable treatment option for patients with refractory RVF. We here present a novel percutaneously implantable device for right ventricular support. The PERKAT device is based on a nitinol stent cage, which is covered with valve-carrying foils. A flexible outlet trunk with a pigtail tip is connected to the distal part. The device is driven by an intra-aortic balloon pump (IABP) drive unit, which inflates/deflates a standard IABP-balloon placed within the stent cage. In-vitro evaluation was done in a liquid bath containing water or blood analog. The PERKAT device was tested in different afterload settings using two different IABP-balloons and varying inflation/deflation rates. We detected flow rates ranging from 1.97 to 3.93 L/min depending on the afterload setting, inflation/deflation rate, balloon size, and the medium used. Flow rates between water and blood analog were nearly comparable, and in the higher inflation/deflation rate settings slightly higher with water. Based on this promising in vitro data, the innovative percutaneously implantable PERKAT device has a potential to become a therapeutic option for patients with RVF refractory to medical treatment. PMID:27831998

  7. Occupational exposure in prostate permanent implants with I-125 seeds

    Energy Technology Data Exchange (ETDEWEB)

    Fdez Garcia, J.; Luna, V.; Sancho, J. M. g.; Martinez, J.; Galiano, P. S.; Jimenez, I.; Prada, P.; Juan, G.; Vivanco, J.


    Prostate brachytherapy is one of the techniques increasing faster in the environment of the radiotherapy and will probably go on increasing in the future. There are two forms in their use; by means of remote afterloading high dose rate (HDR) with Ir-192 radioactive sources or by means of permanent implant by manual/automatic afterloading of low dose rate (LDR) with seeds of I-125 or Pd-103. Iodine-125 has a half life of 59.4 days and it decays by electron capture with emissions of characteristic photons and electrons. The electrons are absorbed by the titanium wall of the I-125 seed. The principal photon emissions are 27.4 and 31.4 keV X-rays and a 35.5 keV gamma ray. Besides 22.1 and 25.2 keV fluorescent X-rays are also emitted resulting from interactions of the iodine-125 photons with the silver rod. The resulting average photon energy is approximately 27.4 keV. (Author)

  8. The Valsalva maneuver: mechanisms and clinical implications. (United States)

    Porth, C J; Bamrah, V S; Tristani, F E; Smith, J J


    The previous discussion has focused on the mechanisms, both respiratory and circulatory, that occur during the Valsalva maneuver. The increase in intrathoracic pressure that occurs during the Valsalva maneuver incites a sequence of rapid changes in preload and afterload stress. During the strain, venous return to the heart is decreased and peripheral venous pressures become increased. Within the next few beats, systolic and pulse pressures begin to fall while mean arterial pressure remains near (or is elevated above) control levels owing to the transmission of airway pressure. Thus it would appear that the benefits to cardiac contractility derived from a decrease in systolic and pulse pressure are counterbalanced by an increase in mean arterial pressure. Increases in total peripheral resistance that begin after about 7 seconds of strain produce further increases in afterload. Recruitment of autonomically mediated increases in heart rate and cardiac contractility assists the heart to maintain its cardiac output in the presence of diminished venous return. With the increased venous return that accompanies termination of Valsalva strain, there is an increase in diastolic filling and stroke volume output by means of the Frank-Starling mechanism. Heart rate and total peripheral resistance continue to be increased during the immediate poststrain period, and the ejection of an increased stroke volume into a constricted arterial system produces a rapid and marked increase in arterial pressure--the phase IV overshoot with its subsequent slowing of heart rate.

  9. Simulation of the Frank-Starling Law of the Heart

    Directory of Open Access Journals (Sweden)

    Samo Ribarič


    Full Text Available We developed a lumped parameter, computer-based model of an equivalent electronic circuit for a one-atrium one-ventricle (frog heart attached to a vascular circuit, to simulate a basic concept of cardiovascular physiology, the Frank-Starling Law of the Heart. A series of simulations was performed, to observe changes in cardiovascular variables (e.g., arterial pressure, ventricular volume, and valve flows if either preload or afterload was increased. The simulated data agreed qualitatively, and quantitatively when experimental data are available, with data obtained on amphibian or on mammalian myocardium. In addition, the data obtained in these simulations improve our understanding of the mechanism(s whereby the heart muscle adapts itself to increased distension (increased preload or to impeded systolic contraction (increased afterload. The analysis of the measured valve flows suggests that the ventricle is a highly input sensitive pump because the input pressure determines the diastolic distension and, consequently, the force of ventricular systolic contraction. On the other hand, the ventricle is a relatively output insensitive pump. Therefore, not only atrium contraction, but also predominantly the preceding ventricular systolic contraction is the main mechanism of the subsequent diastolic ventricular filling. We conclude that the presented model enables the study of basic concepts of cardiovascular physiology.

  10. Presentation of therapy scheme and irradiation technique of short-term contact radiotherpy of the carcinoma of the cervix

    Energy Technology Data Exchange (ETDEWEB)

    Annweiler, H.; Roth, S.L.; Thesen, N.; Sack, H.


    Since April 1983 patients with gynecologic tumors have been irradiated with the HDR afterloading method at the University Hospital of Cologne. The therapy scheme for the carcinoma of the cervix consists of a combination of intracavitary contact irradiation and external radiotherapy. Brachytherapy is preponderant in an early stage of tumor extension, whereas teletherapy contributes more to the total dose in advanced stages. At first, the pelvis is totally exposed to a homogenous irradiation, so the shrunken tumor can more easily be arrived by curietherapy. The therapy scheme is described for the different tumor stages with its dosages, fractionations, and treatment pauses. Besides the use of special multiple-way applicators, the risk organs are protected by collimating with a block the middle part of the external irradiation field as soon as the maximum permissible dose is reached. A special block shape minimizes the dose irregularities at the field borders. The total physical dose at point A is about 60 Gy. The high dose rate of HDR afterloading has to be considered when calculating the biologic efficient dose. Here the dose rate factor furnishes a rough relation to the established radium dosage.

  11. Abnormal Wave Reflections and Left Ventricular Hypertrophy Late After Coarctation of the Aorta Repair (United States)

    Quail, Michael A.; Short, Rebekah; Pandya, Bejal; Steeden, Jennifer A.; Khushnood, Abbas; Taylor, Andrew M.; Segers, Patrick


    Patients with repaired coarctation of the aorta are thought to have increased afterload due to abnormalities in vessel structure and function. We have developed a novel cardiovascular magnetic resonance protocol that allows assessment of central hemodynamics, including central aortic systolic blood pressure, resistance, total arterial compliance, pulse wave velocity, and wave reflections. The main study aims were to (1) characterize group differences in central aortic systolic blood pressure and peripheral systolic blood pressure, (2) comprehensively evaluate afterload (including wave reflections) in the 2 groups, and (3) identify possible biomarkers among covariates associated with elevated left ventricular mass (LVM). Fifty adult patients with repaired coarctation and 25 age- and sex-matched controls were recruited. Ascending aorta area and flow waveforms were obtained using a high temporal-resolution spiral phase-contrast cardiovascular magnetic resonance flow sequence. These data were used to derive central hemodynamics and to perform wave intensity analysis noninvasively. Covariates associated with LVM were assessed using multivariable linear regression analysis. There were no significant group differences (P≥0.1) in brachial systolic, mean, or diastolic BP. However central aortic systolic blood pressure was significantly higher in patients compared with controls (113 versus 107 mm Hg, P=0.002). Patients had reduced total arterial compliance, increased pulse wave velocity, and larger backward compression waves compared with controls. LVM index was significantly higher in patients than controls (72 versus 59 g/m2, Pcoarctation of the aorta repair, including abnormal wave reflections that are associated with elevated LVM. PMID:28115510

  12. Fontan's circulation with dextrocardia, recent pulmonary embolism, and inferior vena cava filter: Anesthetic challenges for urgent hysterectomy. (United States)

    Singh, Preet Mohinder; Borle, Anuradha; Ramachandran, Rashmi; Trikha, Anjan; Goudra, Basavana Gouda


    Fontan's circulation is a unique challenge for the anesthesiologist. Venous pressure is the only source of blood flow for the pulmonary circulation. Patients with such circulation are extremely sensitive to progression of cyanosis (decreased pulmonary blood flow) or circulatory failure. Any major venous compression can compromise the pulmonary blood flow worsening cyanosis; simultaneously, an increased afterload can precipitate circulatory failure. We present a rare patient of surgically corrected Ivemark syndrome with Fontan's physiology with dextrocardia who developed a large uterine fibroid compressing inferior vena cava (IVC). As a result of compression, not only the pulmonary circulation was compromised but she also developed stasis-induced venous thrombosis in the lower limbs that lead to pulmonary embolism (PE) (increased afterload). In addition to oral anticoagulation an IVC filter was inserted to prevent ongoing recurrent PE. Further, to prevent both circulatory compromise and deep venous thrombosis an urgent myomectomy/hysterectomy was planned. In the present case, we discuss the issues involved in the anesthetic management of such patients and highlight the lacunae in the present guidelines for managing perioperative anticoagulation these situations.

  13. Fontan′s circulation with dextrocardia, recent pulmonary embolism, and inferior vena cava filter: Anesthetic challenges for urgent hysterectomy

    Directory of Open Access Journals (Sweden)

    Preet Mohinder Singh


    Full Text Available Fontan′s circulation is a unique challenge for the anesthesiologist. Venous pressure is the only source of blood flow for the pulmonary circulation. Patients with such circulation are extremely sensitive to progression of cyanosis (decreased pulmonary blood flow or circulatory failure. Any major venous compression can compromise the pulmonary blood flow worsening cyanosis; simultaneously, an increased afterload can precipitate circulatory failure. We present a rare patient of surgically corrected Ivemark syndrome with Fontan′s physiology with dextrocardia who developed a large uterine fibroid compressing inferior vena cava (IVC. As a result of compression, not only the pulmonary circulation was compromised but she also developed stasis-induced venous thrombosis in the lower limbs that lead to pulmonary embolism (PE (increased afterload. In addition to oral anticoagulation an IVC filter was inserted to prevent ongoing recurrent PE. Further, to prevent both circulatory compromise and deep venous thrombosis an urgent myomectomy/hysterectomy was planned. In the present case, we discuss the issues involved in the anesthetic management of such patients and highlight the lacunae in the present guidelines for managing perioperative anticoagulation these situations.

  14. Our experience with implantation of VentrAssist left ventricular assist device

    Directory of Open Access Journals (Sweden)

    Hiriyur Shivalingappa Jayanthkumar


    Full Text Available Perioperative anaesthetic management of the VentrAssist TM left ventricular assist device (LVAD is a challenge for anaesthesiologists because patients presenting for this operation have long-standing cardiac failure and often have associated hepatic and renal impairment, which may significantly alter the pharmacokinetics of administered drugs and render the patients coagulopathic. The VentrAssist is implanted by midline sternotomy. A brief period of cardiopulmonary bypass (CPB for apical cannulation of left ventricle is needed. The centrifugal pump, which produces non-pulsatile, continuous flow, is positioned in the left sub-diaphragmatic pocket. This LVAD is preload dependent and afterload sensitive. Transoesophageal echocardiography is an essential tool to rule out contraindications and to ensure proper inflow cannula position, and following the implantation of LVAD, to ensure right ventricular (RV function. The anaesthesiologist should be prepared to manage cardiac decompensation and acute desaturation before initiation of CPB, as well as RV failure and severe coagulopathic bleeding after CPB. Three patients had undergone implantation of VentrAssist in our hospital. This pump provides flow of 5 l/min depending on preload, afterload and pump speed. All the patients were discharged after an average of 30 days. There was no perioperative mortality.

  15. Right ventricular nitric oxide signaling in an ovine model of congenital heart disease: a preserved fetal phenotype. (United States)

    Kameny, Rebecca Johnson; He, Youping; Morris, Catherine; Sun, Christine; Johengen, Michael; Gong, Wenhui; Raff, Gary W; Datar, Sanjeev A; Oishi, Peter E; Fineman, Jeffrey R


    We recently reported superior right ventricle (RV) performance in response to acute afterload challenge in lambs with a model of congenital heart disease with chronic left-to-right cardiac shunts. Compared with control animals, shunt lambs demonstrated increased contractility because of an enhanced Anrep effect (the slow increase in contractility following myocyte stretch). This advantageous physiological response may reflect preservation of a fetal phenotype, since the RV of shunt lambs remains exposed to increased pressure postnatally. Nitric oxide (NO) production by NO synthase (NOS) is activated by myocyte stretch and is a necessary intermediary of the Anrep response. The purpose of this study was to test the hypothesis that NO signaling is increased in the RV of fetal lambs compared with controls and shunt lambs have persistence of this fetal pattern. An 8-mm graft was placed between the pulmonary artery and aorta in fetal lambs (shunt). NOS isoform expression, activity, and association with activating cofactors were determined in fetal tissue obtained during late-gestation and in 4-wk-old juvenile shunt and control lambs. We demonstrated increased RNA and protein expression of NOS isoforms and increased total NOS activity in the RV of both shunt and fetal lambs compared with control. We also found increased NOS activation and association with cofactors in shunt and fetal RV compared with control. These data demonstrate preserved fetal NOS phenotype and NO signaling in shunt RV, which may partially explain the mechanism underlying the adaptive response to increased afterload seen in the RV of shunt lambs.

  16. Evaluation of a Model-Based Hemodynamic Monitoring Method in a Porcine Study of Septic Shock

    Directory of Open Access Journals (Sweden)

    James A. Revie


    Full Text Available Introduction. The accuracy and clinical applicability of an improved model-based system for tracking hemodynamic changes is assessed in an animal study on septic shock. Methods. This study used cardiovascular measurements recorded during a porcine trial studying the efficacy of large-pore hemofiltration for treating septic shock. Four Pietrain pigs were instrumented and induced with septic shock. A subset of the measured data, representing clinically available measurements, was used to identify subject-specific cardiovascular models. These models were then validated against the remaining measurements. Results. The system accurately matched independent measures of left and right ventricle end diastolic volumes and maximum left and right ventricular pressures to percentage errors less than 20% (except for the 95th percentile error in maximum right ventricular pressure and all R2>0.76. An average decrease of 42% in systemic resistance, a main cardiovascular consequence of septic shock, was observed 120 minutes after the infusion of the endotoxin, consistent with experimentally measured trends. Moreover, modelled temporal trends in right ventricular end systolic elastance and afterload tracked changes in corresponding experimentally derived metrics. Conclusions. These results demonstrate that this model-based method can monitor disease-dependent changes in preload, afterload, and contractility in porcine study of septic shock.

  17. A Physical Heart Failure Simulation System Utilizing the Total Artificial Heart and Modified Donovan Mock Circulation. (United States)

    Crosby, Jessica R; DeCook, Katrina J; Tran, Phat L; Betterton, Edward; Smith, Richard G; Larson, Douglas F; Khalpey, Zain I; Burkhoff, Daniel; Slepian, Marvin J


    With the growth and diversity of mechanical circulatory support (MCS) systems entering clinical use, a need exists for a robust mock circulation system capable of reliably emulating and reproducing physiologic as well as pathophysiologic states for use in MCS training and inter-device comparison. We report on the development of such a platform utilizing the SynCardia Total Artificial Heart and a modified Donovan Mock Circulation System, capable of being driven at normal and reduced output. With this platform, clinically relevant heart failure hemodynamics could be reliably reproduced as evidenced by elevated left atrial pressure (+112%), reduced aortic flow (-12.6%), blunted Starling-like behavior, and increased afterload sensitivity when compared with normal function. Similarly, pressure-volume relationships demonstrated enhanced sensitivity to afterload and decreased Starling-like behavior in the heart failure model. Lastly, the platform was configured to allow the easy addition of a left ventricular assist device (HeartMate II at 9600 RPM), which upon insertion resulted in improvement of hemodynamics. The present configuration has the potential to serve as a viable system for training and research, aimed at fostering safe and effective MCS device use.

  18. Physiological characterization of the SynCardia total artificial heart in a mock circulation system. (United States)

    Crosby, Jessica R; DeCook, Katrina J; Tran, Phat L; Smith, Richard G; Larson, Douglas F; Khalpey, Zain I; Burkhoff, Daniel; Slepian, Marvin J


    The SynCardia total artificial heart (TAH) has emerged as an effective, life-saving biventricular replacement system for a wide variety of patients with end-stage heart failure. Although the clinical performance of the TAH is established, modern physiological characterization, in terms of elastance behavior and pressure-volume (PV) characterization has not been defined. Herein, we examine the TAH in terms of elastance using a nonejecting left ventricle, and then characterize the PV relation of the TAH by varying preload and afterload parameters using a Donovan Mock Circulatory System. We demonstrate that the TAH does not operate with time-varying elastance, differing from the human heart. Furthermore, we show that the TAH has a PV relation behavior that also differs from that of the human heart. The TAH does exhibit Starling-like behavior, with output increasing via preload-dependent mechanisms, without reliance on an alteration of inotropic state within the operating window of the TAH. Within our testing range, the TAH is insensitive to variations in afterload; however, this insensitivity has a limit, the limit being the maximum driving pressure of the pneumatic driver. Understanding the physiology of the TAH affords insight into the functional parameters that govern artificial heart behavior providing perspective on differences compared with the human heart.

  19. Nitric oxide improves the hemodynamic performance of the hypoxic goldfish (Carassius auratus) heart

    DEFF Research Database (Denmark)

    Imbrogno, Sandra; Capria, C.; Tota, Bruno;


    nitric oxide (NO) under normoxic and hypoxic conditions. Cardiac performance was examined both under basal (constant preload and afterload) and loading conditions, i.e. preload-induced increases in stroke volume (SV) and hence cardiac output at constant afterload (the Frank–Starling response). Hypoxic...... to filling pressure increases; the maximum SV = 1.08 ± 0.09 mL/kg body mass was obtained at 0.4 kPa. Acute hypoxia increased this sensitivity, SV reaching the maximum value (1.45 ± 0.12 mL/kg body mass) at 0.25 kPa. NOS inhibition by L-NMMA reduced the Frank–Starling response under normoxia......, but was ineffective under acute hypoxia, where NO may come from nitrite reduction. In both conditions, sGC inhibition induced a reduction of the cardiac response to preload. Moreover, under acute hypoxia, NO scavenging significantly reduced the Frank–Starling response. The hypoxia-induced hemodynamic patterns were...

  20. Simulation of the Frank-Starling Law of the Heart. (United States)

    Ribarič, Samo; Kordaš, Marjan


    We developed a lumped parameter, computer-based model of an equivalent electronic circuit for a one-atrium one-ventricle (frog) heart attached to a vascular circuit, to simulate a basic concept of cardiovascular physiology, the Frank-Starling Law of the Heart. A series of simulations was performed, to observe changes in cardiovascular variables (e.g., arterial pressure, ventricular volume, and valve flows) if either preload or afterload was increased. The simulated data agreed qualitatively, and quantitatively when experimental data are available, with data obtained on amphibian or on mammalian myocardium. In addition, the data obtained in these simulations improve our understanding of the mechanism(s) whereby the heart muscle adapts itself to increased distension (increased preload) or to impeded systolic contraction (increased afterload). The analysis of the measured valve flows suggests that the ventricle is a highly input sensitive pump because the input pressure determines the diastolic distension and, consequently, the force of ventricular systolic contraction. On the other hand, the ventricle is a relatively output insensitive pump. Therefore, not only atrium contraction, but also predominantly the preceding ventricular systolic contraction is the main mechanism of the subsequent diastolic ventricular filling. We conclude that the presented model enables the study of basic concepts of cardiovascular physiology.

  1. Effect of transverse aortic constriction on cardiac structure, function and gene expression in pregnant rats.

    Directory of Open Access Journals (Sweden)

    Nils Thomas Songstad

    Full Text Available BACKGROUND: There is an increased risk of heart failure and pulmonary edema in pregnancies complicated by hypertensive disorders. However, in a previous study we found that pregnancy protects against fibrosis and preserves angiogenesis in a rat model of angiotensin II induced cardiac hypertrophy. In this study we test the hypothesis that pregnancy protects against negative effects of increased afterload. METHODS: Pregnant (gestational day 5.5-8.5 and non-pregnant Wistar rats were randomized to transverse aortic constriction (TAC or sham surgery. After 14.2 ± 0.14 days echocardiography was performed. Aortic blood pressure and left ventricular (LV pressure-volume loops were obtained using a conductance catheter. LV collagen content and cardiomyocyte circumference were measured. Myocardial gene expression was assessed by real-time polymerase chain reaction. RESULTS: Heart weight was increased by TAC (p<0.001 but not by pregnancy. Cardiac myocyte circumference was larger in pregnant compared to non-pregnant rats independent of TAC (p = 0.01, however TAC per se did not affect this parameter. Collagen content in LV myocardium was not affected by pregnancy or TAC. TAC increased stroke work more in pregnant rats (34.1 ± 2.4 vs 17.5 ± 2.4 mmHg/mL, p<0.001 than in non-pregnant (28.2 ± 1.7 vs 20.9 ± 1.5 mmHg/mL, p = 0.06. However, it did not lead to overt heart failure in any group. In pregnant rats, α-MHC gene expression was reduced by TAC. Increased in the expression of β-MHC gene was higher in pregnant (5-fold compared to non-pregnant rats (2-fold after TAC (p = 0.001. Nine out of the 19 genes related to cardiac remodeling were affected by pregnancy independent of TAC. CONCLUSIONS: This study did not support the hypothesis that pregnancy is cardioprotective against the negative effects of increased afterload. Some differences in cardiac structure, function and gene expression between pregnant and non-pregnant rats following TAC indicated that

  2. Prognostic utility of blood pressure-adjusted global and basal systolic longitudinal strain

    Directory of Open Access Journals (Sweden)

    Isaac B Rhea


    Full Text Available Assessment of global longitudinal systolic strain (GLS and longitudinal systolic strain of the basal segments (BLS has shown prognostic value in cardiac disorders. However, strain is reduced with increased afterload. We assessed the prognostic value of GLS and BLS adjusted for afterload. GLS and BLS were determined in 272 subjects with normal ejection fraction and no known coronary disease, or significant valve disease. Systolic blood pressure (SP and diastolic blood pressure (DP obtained at the time of echocardiography were used to adjust GLS and BLS as follows: strain × SP (mmHg/120 mmHg and strain × DP (mmHg/80 mmHg. Patients were followed for cardiac events and mortality. The mean age was 53 ± 15 years and 53% had hypertension. There were 19 cardiac events and 70 deaths over a mean follow-up of 26 ± 14 months. Cox analysis showed that left ventricular mass index (P = 0.001, BLS (P < 0.001, and DP-adjusted BLS (P < 0.001 were independent predictors of cardiac events. DP-adjusted BLS added incremental value (P < 0.001 to the other two predictors and had an area under the curve of 0.838 for events. DP (P = 0.001, age (P = 0.001, ACE inhibitor use (P = 0.017, and SP-adjusted BLS (P = 0.012 were independent predictors of mortality. SP-adjusted BLS added incremental value (P = 0.014 to the other independent predictors. In conclusion, DP-adjusted BLS and SP-adjusted BLS were independent predictors of cardiac events and mortality, respectively. Blood pressure-adjusted strain added incremental prognostic value to other predictors of outcome. Introduction Assessment of global longitudinal systolic strain (GLS and basal longitudinal systolic strain (BLS have shown utility for prediction of prognosis in various cardiac disorders (1, 2, 3, 4. In some studies, longitudinal strain has been shown to be a more sensitive indicator of left ventricular (LV systolic dysfunction than traditional measures of function (5, 6. The detection of early

  3. Interstitial hyperthermia in combination with brachytherapy. (United States)

    Coughlin, C T; Douple, E B; Strohbehn, J W; Eaton, W L; Trembly, B S; Wong, T Z


    Flexible coaxial cables were modified to serve as microwave antennas operating at a frequency of 915 MHz. These antennas were inserted into nylon afterloading tubes that had been implanted in tumors using conventional interstitial implantation techniques for iridium-192 seed brachytherapy. The tumor volume was heated to 42-45 degrees C within 15 minutes and heating was continued for a total of 1 hour per treatment. Immediately following a conventional brachytherapy dose and removal of the iridium seeds the tumors were heated again in a second treatment. This interstitial technique for delivering local hyperthermia should be compatible with most brachytherapy methods. The technique has proved so far to be practical and without complications. Temperature distributions obtained in tissue phantoms and a patient are described.

  4. Experiences of high dose rate interstitial brachytherapy for carcinoma of the mobile tongue

    Energy Technology Data Exchange (ETDEWEB)

    Ikeda, Hiroshi; Inoue, Toshihiko; Yamazaki, Hideya (Osaka Univ. (Japan). Faculty of Medicine) (and others)


    Interstitial brachytherapy was conducted for mobile tongue carcinoma using a high dose rate remote afterloading machine with small [sup 192]I source. Detailed method, named as 'linked double-botton technique', is to approach from submandibular skin by an open-ended stainless steel needles to the tongue lesion, and to replace each needle into flexible nylon tube from the oral cavity. Delivered dose was 60 Gy/10 Fr./5-6 days at the distance 5 mm from the source plane. Ten patients with mobile tongue carcinoma Tl-2N0 were treated with this method from October 1991 through August 1992. Local was uncontrolled in one patient, in whom the lesion was combined with leukoplakia at both lateral borders of the tongue. This was in accordance with the result in low dose rate treatment. This can be a substitute to low dose rate system for treatment of mobile tongue carcinoma. (author).

  5. Implementation of a High-Dose-Rate Brachytherapy Program for Carcinoma of the Cervix in Senegal: A Pragmatic Model for the Developing World

    Energy Technology Data Exchange (ETDEWEB)

    Einck, John P., E-mail: [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Hudson, Alana [Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary, Alberta (Canada); Shulman, Adam C. [Overlook Medical Center, Summit, New Jersey (United States); Yashar, Catheryn M. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Dieng, Mamadou M.; Diagne, Magatte; Gueye, Latifatou; Gningue, Fama; Gaye, Pape M. [Départemént de Radiothérapie, Institut Joliot-Curie, Hôpital Aristide Le Dantec, Dakar (Senegal); Fisher, Brandon J. [GammaWest Cancer Services, Salt Lake City, Utah (United States); Mundt, Arno J. [Department of Radiation Medicine and Applied Sciences, University of California San Diego, San Diego, California (United States); Brown, Derek W. [Department of Oncology, Tom Baker Cancer Centre, University of Calgary, Calgary, Alberta (Canada)


    West Africa has one of the highest incidence rates of carcinoma of the cervix in the world. The vast majority of women do not have access to screening or disease treatment, leading to presentation at advanced stages and to high mortality rates. Compounding this problem is the lack of radiation treatment facilities in Senegal and many other parts of the African continent. Senegal, a country of 13 million people, had a single {sup 60}Co teletherapy unit before our involvement and no brachytherapy capabilities. Radiating Hope, a nonprofit organization whose mission is to provide radiation therapy equipment to countries in the developing world, provided a high-dose-rate afterloading unit to the cancer center for curative cervical cancer treatment. Here we describe the implementation of high-dose-rate brachytherapy in Senegal requiring a nonstandard fractionation schedule and a novel treatment planning approach as a possible blueprint to providing this technology to other developing countries.

  6. Long term effect of cervix carcinoma treated by HDR 192 Ir afterloding intracavitory radiotherapy combined with external irradiation.%高剂量率192Ir后装腔内加外照射治疗宫颈癌的远期疗效分析

    Institute of Scientific and Technical Information of China (English)

    王青; 侯晓玲; 赵淑红


    Objective To analyze retrosrectively long- term effect of cervix carcinona treated by HDR 192Ir afterloading intracavitory radiotherapy combined with external irradiation. Methods From Mar 1993 to Dec 1994, 128 cases of cervix cancer(age from 29 years to 80 years) were treated with combination of external irradiation and HDR 192Ir afterloading intracavitory radiotherapy. 47 cases were stage Ⅱ and 81 were stage Ⅲ. The dose of external radiotherapy was 40 Gy or 50 Gy and afterloading irradiation was given in 6 or 7 fractions of 8 Gy. Results The overall local tumor control was 94.5%, the 1,3,5 year survival rates were 91.61%, 81.89%and 67.36%. The 1,3,5 year survival rates of stage Ⅱ and stage Ⅲ cases were 95.28% and 89. 47%, 87.19% and 79.50%, 72.76% and 64.95% (P>0.05). The rate of severe complications was 7.03% (9/128). Conclusion HDR 192Ir afterloading intracavitory radiotherapy combined with external irradiation for cervix carcinoma is effective and less side effects.%目的分析高剂量率192Ir后装腔内加外照射治疗宫颈癌的远期疗效及并发症。方法对128例Ⅱ、Ⅲ期放疗后宫颈癌进行了回顾分析。其中Ⅱ期47例,Ⅲ期81例。全盆腔外照射Dr20Gy/10次,全盆中间挡铅4cmDr20Gy~30Gy/10次~15次;后装A点剂量48Gy~56Gy/6次~7次。结果 1、3、5年生存率分别为91.61%、81.8%和67.36%;Ⅱ、Ⅲ期1、3、5年生存率无统计学差异(P>0.05);远期严重并发症的发生率7.03%(9/128)。结论高剂量率192Ir后装腔内加外照射治疗宫颈癌疗效肯定,并发症少。盆腔局部复发仍是放疗失败的主要原因。

  7. [Understanding heart failure]. (United States)

    Boo, José Fernando Guadalajara


    Heart failure is a disease with several definitions. The term "heart failure" is used by has brougth about confusion in the terminology. For this reason, the value of the ejection fraction (< 0.40 or < 0.35) is used in most meganalyses on the treatment of heart failure, avoiding the term "heart failure" that is a confounding concept. In this paper we carefully analyze the meaning of contractility, ventricular function or performance, preload, afterload, heart failure, compensation mechanisms in heart failure, myocardial oxygen consumption, inadequate, adequate and inappropriate hypertrophy, systole, diastole, compliance, problems of relaxation, and diastolic dysfunction. Their definitions are supported by the original scientific descriptions in an attempt to clarify the concepts about ventricular function and heart failure and, in this way, use the same scientific language about the meaning of ventricular function, heart failure, and diastolic dysfunction.

  8. The Role of Obesity in the Development of Left Ventricular Hypertrophy Among Children and Adolescents. (United States)

    Brady, Tammy M


    Both obesity and hypertension have increased substantially among children over the last several decades. At the same time, mounting evidence has pointed to the role of these and other cardiovascular disease risk factors on the development of end organ damage such as left ventricular hypertrophy in children. While traditionally thought to occur in response to an increased afterload as in systemic hypertension, evidence demonstrates that obesity is associated with left ventricular hypertrophy independent of blood pressure. Both hemodynamic and non-hemodynamic factors contribute to the pathogenesis of obesity-related left ventricular remodeling. However, more contemporary research suggests that adiposity and blood pressure have a greater effect on left ventricular geometry when present together than when present alone. Normalization of left ventricular mass in obese hypertensive individuals requires achievement of both normotension and weight loss. Additional strategies are needed to promote the cardiovascular health of children, with greater emphasis placed on obesity prevention.

  9. State of the evidence: mechanical ventilation with PEEP in patients with cardiogenic shock. (United States)

    Wiesen, Jonathan; Ornstein, Moshe; Tonelli, Adriano R; Menon, Venu; Ashton, Rendell W


    The need to provide invasive mechanical ventilatory support to patients with myocardial infarction and acute left heart failure is common. Despite the large number of patients requiring mechanical ventilation in this setting, there are remarkably few data addressing the ideal mode of respiratory support in such patients. Although there is near universal acceptance regarding the use of non-invasive positive pressure ventilation in patients with acute pulmonary oedema, there is more concern with invasive positive pressure ventilation owing to its more significant haemodynamic impact. Positive end-expiratory pressure (PEEP) is almost universally applied in mechanically ventilated patients due to benefits in gas exchange, recruitment of alveolar units, counterbalance of hydrostatic forces leading to pulmonary oedema and maintenance of airway patency. The limited available clinical data suggest that a moderate level of PEEP is safe to use in severe left ventricular (LV) dysfunction and cardiogenic shock, and may provide haemodynamic benefits as well in LV failure which exhibits afterload-sensitive physiology.

  10. Implementation of a high-dose-rate brachytherapy program for carcinoma of the cervix in Senegal: a pragmatic model for the developing world. (United States)

    Einck, John P; Hudson, Alana; Shulman, Adam C; Yashar, Catheryn M; Dieng, Mamadou M; Diagne, Magatte; Gueye, Latifatou; Gningue, Fama; Gaye, Pape M; Fisher, Brandon J; Mundt, Arno J; Brown, Derek W


    West Africa has one of the highest incidence rates of carcinoma of the cervix in the world. The vast majority of women do not have access to screening or disease treatment, leading to presentation at advanced stages and to high mortality rates. Compounding this problem is the lack of radiation treatment facilities in Senegal and many other parts of the African continent. Senegal, a country of 13 million people, had a single (60)Co teletherapy unit before our involvement and no brachytherapy capabilities. Radiating Hope, a nonprofit organization whose mission is to provide radiation therapy equipment to countries in the developing world, provided a high-dose-rate afterloading unit to the cancer center for curative cervical cancer treatment. Here we describe the implementation of high-dose-rate brachytherapy in Senegal requiring a nonstandard fractionation schedule and a novel treatment planning approach as a possible blueprint to providing this technology to other developing countries.

  11. The thickened left ventricle: etiology, differential diagnosis and implications for cardiovascular radiology; Der dicke linke Ventrikel. Ursachen und Differenzialdiagnose der linksventrikulaeren Hypertrophie und Implikationen fuer die kardiovaskulaere Radiologie

    Energy Technology Data Exchange (ETDEWEB)

    Bischoff, P.; Barkhausen, J.; Hunold, P. [Universitaetsklinikum Schleswig-Holstein, Luebeck (Germany). Klinik fuer Radiologie und Nuklearmedizin; Radke, P.W. [Universitaetsklinikum Schleswig Holstein, Luebeck (Germany). Medizinische Klinik II


    Hypertrophy of the left ventricular myocardium is a common finding and can be reliably detected by echocardiography, CT and MRI. Common causes include diseases associated with increased cardiac afterload as well as primary and secondary cardiomyopathy. With the opportunity to determine functional parameters and myocardial mass precisely as well as to detect structural changes of the cardiac muscle simultaneously, cardiac MRI is the most precise imaging method for quantifying left ventricular hypertrophy as well as determining the cause and the exact characterization of the myocardial changes. It is mandatory, however, to create a flexible, individually adapted examination protocol. This review presents useful diagnostic algorithms in relation to different underlying pathologies in patients with left ventricular hypertrophy. (orig.)

  12. Methodology, results and experience of independent brachytherapy plan verifications based on DICOM standard; Implementacion, resultados y experiencia de una verificacion independiente de tratamientos de braquiterapia basada en el estandar DICOM

    Energy Technology Data Exchange (ETDEWEB)

    Ferrando Sanchez, A.; Pardo Perez, E.; Castro Novals, J.; Casa de Julian, M. A. de la; Cabello Murillo, E.; Diaz Fuentes, R.; Molina Lopez, M. Y.


    The use of a high dose rate source together with an afterloading treatment delivery in brachytherapy plans allows for dose modulation minimizing dose to staff. An independent verification of the exported data to the treatment station is required by local regulations (being also a widely accepted recommendation on the international literature). We have developed a methodology under home brew code to import DICOM treatment data onto an Excel spreadsheet that is able to calculate dose on given reference points using the TG-43 formalism of the AAPM3-5. It employs analytic fits of anisotropy factor and radial dose function for different sources. The end point implementations we present here allow merging in one step an independent verification and a treatment printout. The use of DICOM standard makes our code versatile and provides greater compatibility with respect to current treatment planning systems. (Author)

  13. New approach for new target: adaptive servo-ventilation on Cheyne-Stokes respiration in congestive heart failure

    Institute of Scientific and Technical Information of China (English)


    @@ Cheyne-Stokes respiration with central sleep apnea (CSR-CSA) occurs when periods of hyperventilation with waxing/waning tidal volume alternated with periods of central hypopnea/apnea. It is present in approximately 40 percent of patients with severe congestive heart failure (CHF). CSR-CSA may contribute to the progression of heart failure by causing repetitive arterial oxygen desaturation, sleep fragmentation, increased left ventricular afterload, activation of sympathetic nervous system, and oscillations in heart rate and blood pressure. There are evidences indicating that CSR-CSA is associated with a remarkable increase in mortality and is also an independent risk factor for cardiac transplantation; furthermore, treatment of CSR-CSA in combination with optimal medical therapy may influence the course of chronic heart failure, improve quality of life and the survival of patients.1 The paper by Zhang et al2 highlights the importance of recognizing this pathological breathing pattern as a potential therapeutic target.

  14. Metastatic hepatocellular carcinoma of the external auditory canal

    Institute of Scientific and Technical Information of China (English)


    This report describes a rare case of metastatic hepatocellular carcinoma (HCC) presenting a huge mass in the left external auditory canal (EAC). The patient was a 55-year-old man with hepatitis B virus-related HCC.He presented to our department with a three-month history of increasing left otalgia, and hearing loss with recent fresh aural bleeding. Histopathologic examination indicated that the tumor was secondary to HCC. Although external irradiation was not effective, the tumor was treated with surgical debulking and high dose rate 192 Ir remote afterloading system (RALS) for postoperative intracavitary irradiation. A review of the literature revealed only five other cases of HCC metastasis to the temporal bone, all of which mainly metastasteed in the internal acoustic meatus. The present case is the first report of HCC metastasis to the EAC.

  15. Association of Right Ventricular Pressure and Volume Overload with Non-Ischemic Septal Fibrosis on Cardiac Magnetic Resonance.

    Directory of Open Access Journals (Sweden)

    Jiwon Kim

    Full Text Available Non-ischemic fibrosis (NIF on cardiac magnetic resonance (CMR has been linked to poor prognosis, but its association with adverse right ventricular (RV remodeling is unknown. This study examined a broad cohort of patients with RV dysfunction, so as to identify relationships between NIF and RV remodeling indices, including RV pressure load, volume and wall stress.The population comprised patients with RV dysfunction (EF 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001.Among wall stress components, NIF was independently associated with RV chamber dilation and afterload, supporting the concept that NIF is linked to adverse RV chamber remodeling.

  16. Protective effect of pulmonary hypertension against right-sided tamponade in pericardial effusion. (United States)

    Khan, M Usman; Khouzam, Rami N


    Patients with pericardial effusion are susceptible to cardiac tamponade. A compressing circumferential pericardial effusion typically results in an equalization of intracardiac and pericardial pressure during diastole and a progressive collapse of the right atrium and ventricle. Pulmonary hypertension that increases the afterload of the right ventricle may result in elevated pressures initially in the right ventricle and subsequently in the right atrium. This may lead to right ventricular hypertrophy and a pathologic structural and functional remodeling of both right heart chambers. Conversely, elevated pressures within the right heart chambers caused by longstanding pulmonary hypertension may resist and protect against tamponade of these chambers in the setting of a coexisting pericardial effusion. In such cases, a sudden reduction in pulmonary arterial pressures may result in tamponade of the right heart chambers.

  17. Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate

    Directory of Open Access Journals (Sweden)

    Jain Amit


    Full Text Available We describe the anesthetic management of a patient with hypertrophic obstructive cardiomyopathy with dual-chamber pacemaker undergoing transurethral resection of the prostate. Anesthetic challenges included prevention and management of perioperative arrhythmias, maintenance of adequate preload, afterload and heart rate to relieve left ventricular outflow tract obstruction and considerations related to the presence of dual-chamber pacemaker and TURP. We recommend preoperative reprogramming of the DDD pacemaker, avoidance of magnet application during the procedure, application of electrosurgical unit current returning pad to the anterior aspect of the thigh, especially if monopolar cautery is used, use of central venous pressure line for estimation of preload and careful titration of anesthetic drugs to maintain stable hemodynamics.

  18. Mathematical Model for Hemodynamicand Hormonal Effects of Human Ghrelin in Healthy Volunteers

    Directory of Open Access Journals (Sweden)



    Full Text Available Hemodynamicand hormonal effects of human ghrelin in healthy volunteers.To investigate hemodynamic and hormonaleffects of ghrelin, a novel growth hormone (GH-releasing peptide, we gave six healthy men an intravenousbolus of human ghrelin or placebo and vice versa1–2 wk apart in a randomized fashion. Ghrelin elicited amarked increase in circulating GH . The elevation ofGH lasted longer than 60 min after the bolus injection.Injection of ghrelin significantly decreased mean arterialpressure without a significant changein heart rate .In summary, human ghrelin elicited a potent, longlastingGH release and had beneficial hemodynamic effectsvia reducing cardiac afterload and increasing cardiac outputwithout an increase in heart rate. Thus, the purpose of thisstudy was to investigate hemodynamic and hormonaleffects of intravenous ghrelin in healthy volunteers. This paper discussed the constant stress level of healthy volunteers with times to damage of stress effect andrecoveries

  19. Mechanical stimulation in the engineering of heart muscle. (United States)

    Liaw, Norman Yu; Zimmermann, Wolfram-Hubertus


    Recreating the beating heart in the laboratory continues to be a formidable bioengineering challenge. The fundamental feature of the heart is its pumping action, requiring considerable mechanical forces to compress a blood filled chamber with a defined in- and outlet. Ventricular output crucially depends on venous loading of the ventricles (preload) and on the force generated by the preloaded ventricles to overcome arterial blood pressure (afterload). The rate of contraction is controlled by the spontaneously active sinus node and transmission of its electrical impulses into the ventricles. The underlying principles for these physiological processes are described by the Frank-Starling mechanism and Bowditch phenomenon. It is essential to consider these principles in the design and evaluation of tissue engineered myocardium. This review focuses on current strategies to evoke mechanical loading in hydrogel-based heart muscle engineering.

  20. Newer methods of cardiac output monitoring

    Institute of Scientific and Technical Information of China (English)

    Yatin; Mehta; Dheeraj; Arora


    Cardiac output(CO) is the volume of blood ejected by each ventricle per minute and is the product of stroke volume and heart rate. CO can thus be manipulated by alteration in heart rate or rhythm, preload, contractility and afterload. Moreover it gives important information about tissue perfusion and oxygen delivery. CO can be measured by various methods and thermodilution method using pulmonary artery catheter(PAC) is till date considered as gold standard method. Complications associated with PAC led to development of newer methods which are minimally or non-invasive. Newer methods fulfil other properties like continuous and reproducible reading, cost effective, reliable during various physiological states and have fast response time. These methods are validated against the gold standard with good level agreement. In this review we have discussed various newer methods of CO monitoring and their effectiveness in clinical use.

  1. The benefit of exercise training in pulmonary hypertension: a clinical review. (United States)

    Chia, Karen S W; Wong, Peter K K; Faux, Steven G; McLachlan, Craig S; Kotlyar, Eugene


    Pulmonary hypertension (PH) is a clinical condition characterised by raised pulmonary artery pressure, which results in increased right ventricular afterload and dyspnoea. This is accompanied by reduced exercise capacity, quality of life and, eventually, death. An increasing range of targeted medications has transformed the treatment of pulmonary arterial hypertension, a specific type of PH. Supervised exercise training is recommended as part of a multifaceted management plan for PH. However, many questions remain regarding how exercise training improves exercise capacity and quality of life. The optimal exercise regimen (frequency, timing, duration and intensity) also remains unclear. This review provides an update on the pathophysiology of exercise impairment in PH, suggests mechanisms by which exercise may improve symptoms and function and offers evidence-based recommendations regarding the frequency and intensity of an exercise programme for patients with PH.

  2. Hindlimb immobilization - Length-tension and contractile properties of skeletal muscle (United States)

    Witzmann, F. A.; Kim, D. H.; Fitts, R. H.


    Casts were placed around rat feet in plantar flexion position to immobilize the soleus muscle in a shortened position, while the other foot was fixed in dorsal flexion to set the extensor digitorum longus in a shortened position. The total muscular atrophy and contractile properties were measured at 1, 2, 4, 7, 14, 21, 28, 35, and 42 days after immobilization, with casts being replaced every two weeks. The slow twitch soleus and the fast-twitch vastus lateralis and longus muscles were excised after termination of the experiment. The muscles were then stretched and subjected to electric shock to elicit peak tetanic tension and peak tetanic tension development. Force velocity features of the three muscles were assayed in a series of afterloaded contractions and fiber lengths were measured from subsequently macerated muscle. All muscles atrophied during immobilization, reaching a new steady state by day 21. Decreases in fiber and sarcomere lengths were also observed.

  3. Right heart failure in acute respiratory distress syndrome: An unappreciated albeit a potential target for intervention in the management of the disease

    Directory of Open Access Journals (Sweden)

    Abhishek Biswas


    Full Text Available Mortality from acute respiratory distress syndrome (ARDS has gone down recently. In spite of this trend, the absolute numbers continue to be high even with improvements in ventilator strategies and a better understanding of fluid management with this disease. A possible reason for this could be an under-recognized involvement of the pulmonary vasculature and the right side of the heart in ARDS. The right heart is not designed to function under situations leading to acute elevations in afterload as seen in ARDS, and hence it decompensates. This brief review focuses on the magnitude of the problem, its detection in the intensive care unit, and recognizes the beneficial effect of prone-positioning on the pulmonary vasculature and right heart.

  4. The pressure-volume relationship of the heart: past, present and future. (United States)

    Sunagawa, Kenji


    The pressure-volume relationship of the heart was first reported more than a century ago. It was not widely accepted, however, until the mid-1970s. The pressure-volume diagram became a central theme of cardiac mechanics once it was shown to be a good representation of ventricular mechanics. Early in 1980s, the introduction of the ventricular interaction with afterload using effective arterial elastance made it possible to translate ventricular mechanical properties represented by the pressure-volume relationship to the pumping ability of the heart. Furthermore incorporating the framework of ventricular arterial interaction into the classic Guyton's circulatory equilibrium early in 2000s enabled us to express quantitatively how mechanical properties of the ventricles and vascular systems determine the circulatory equilibrium. Successful quantitative descriptions of circulatory equilibrium using the pressure-volume concept would promote basic cardiovascular physiology and accelerate its clinical applications.

  5. Dynamic characterization of a new accelerated heart valve tester. (United States)

    Menzler, F; Haubold, A D; Hwang, N H


    This paper presents a new accelerated prosthetic heart valve tester prototype that incorporates a camshaft and poppet valves. A three element Windkessel system is used to mimic the afterload of the human systemic circulation. The device is capable of testing eight valves simultaneously at a rate up to 1,250 cycles/min, while the flow rate, the pressure, and the valve loading can be monitored and adjusted individually. The tester was characterized and calibrated using a set of eight Carpentier-Edwards bioprostheses at a flow rate varying between 3 and 5 L/min. The experiment was carried out with the pressure difference across the closed heart valve maintained between 140 and 190 mmHg. Smooth and complete opening and closing of the valve leaflets was achieved at all cycling rates. This confirms that the velocity profiles approaching the test valves were uniform, an important factor that allows the test valves to open and close synchronously each time.

  6. [New options in the treatment of acute heart failure]. (United States)

    Link, A; Böhm, M


    Acute heart failure is defined as the acute onset of symptoms due to hear failure necessitating emergency therapy. The in-hospital mortality rate ranges up to 10 % and in cardiogenic shock is 50-70 %. In acute heart failure, rapid diagnosis and causal therapy are necessary to avoid cardiogenic shock. In cases of acute coronary syndromes, primary percutaneous intervention should be performed immediately. Medical and apparative treatment strategies focus on decreasing pulmonary congestion, afterload, and neurohormonal activation in order to improve hemodynamics and reduce symptoms of dyspnea. In contrast to chronic heart failure, no medical therapy has been able to reduce mortality rates in acute heart failure. However, new medical therapies should at least improve clinical symptoms of congestion and favorably reduce cardiovascular events, re-hospitalization, and mortality rates.

  7. Patient-specific modeling of left ventricular electromechanics as a driver for haemodynamic analysis (United States)

    Augustin, Christoph M.; Crozier, Andrew; Neic, Aurel; Prassl, Anton J.; Karabelas, Elias; Ferreira da Silva, Tiago; Fernandes, Joao F.; Campos, Fernando; Kuehne, Titus; Plank, Gernot


    Aims Models of blood flow in the left ventricle (LV) and aorta are an important tool for analysing the interplay between LV deformation and flow patterns. Typically, image-based kinematic models describing endocardial motion are used as an input to blood flow simulations. While such models are suitable for analysing the hemodynamic status quo, they are limited in predicting the response to interventions that alter afterload conditions. Mechano-fluidic models using biophysically detailed electromechanical (EM) models have the potential to overcome this limitation, but are more costly to build and compute. We report our recent advancements in developing an automated workflow for the creation of such CFD ready kinematic models to serve as drivers of blood flow simulations. Methods and results EM models of the LV and aortic root were created for four pediatric patients treated for either aortic coarctation or aortic valve disease. Using MRI, ECG and invasive pressure recordings, anatomy as well as electrophysiological, mechanical and circulatory model components were personalized. Results The implemented modeling pipeline was highly automated and allowed model construction and execution of simulations of a patient’s heartbeat within 1 day. All models reproduced clinical data with acceptable accuracy. Conclusion Using the developed modeling workflow, the use of EM LV models as driver of fluid flow simulations is becoming feasible. While EM models are costly to construct, they constitute an important and nontrivial step towards fully coupled electro-mechano-fluidic (EMF) models and show promise as a tool for predicting the response to interventions which affect afterload conditions. PMID:28011839

  8. Management of postoperative radiation injury of the urinary bladder by hyperbaric oxygen (HBO)

    Energy Technology Data Exchange (ETDEWEB)

    Peusch-Dreyer, D.; Dreyer, K.H. [Zentrum fuer Tauch- und Ueberdruckmedizin (ZETUeM), Bremen (Germany); Mueller, C.D. [Druckkammerzentrum Magdeburg (Germany); Carl, U. [Klinik fuer Strahlentherapie und Radioonkologie, Universitaet Duesseldorf (Germany)


    Aim: In many case reports the success of treatment of late complications of radiotherapy with hyperbaric oxygenation (HBO) has been shown. This synopsis attempts to review HBO in the treatment of chronic radiation injury of the bladder. Patients and methods: Three female patients who had developed urge-incontinence after a Wertheim operation and combined brachy-teletherapy with cobalt-60 and afterloading and did not respond to various drug therapies, were treated with HBO to a maximum of 40 applications. Results: In all patients HBO haltered and inverted the dynamic process underlying chronic bladder changes after irradiation. Rationales for the HBO are the reduction of tissue hypoxia and the induction of neoangiogenesis. Conclusions: There are no prospective trials up to date showing the benefit of HBO to urinary disorders caused by radiation cystitis. The positive results of our retrospective study should encourage clinicians to initiate prospective studies with the use of HBO in the treatment of radiation cystitis. (orig.) [Deutsch] Ziel: Ueber die erfolgreiche Anwendung der hyperbaren Sauerstofftherapie (HBO) zur Behandlung von Strahlenspaetkomplikationen ist in zahlreichen Publikationen berichtet worden. Ziel dieser Arbeit ist es, den Einsatz der HBO bei der Behandlung von Miktionsbeschwerden bei chronisch radiogenen Harnblasenschaeden zu bewerten. Patienten und Methode: Drei Patientinnen, die nach einer kombinierten Brachyteletherapie mit Kobalt 60 und Afterloading nach Wertheim-Operation unter einer medikamentoes nicht zu beeinflussenden Urge-Inkontinenz litten, wurden der HBO mit maximal 40 Behandlungen zugefuehrt. Ergebnisse: Die HBO war bei allen Patientinnen in der Lage, den dynamischen Krankheitsprozess der Strahlenzystitis aufzuhalten und teilweise umzukehren. Grundlage hierfuer ist die Beseitigung der Gewebshypoxie. Dieses wiederum stellt die Voraussetzung fuer eine Neovaskularisation im bestrahlten Gewebe dar. Schlussfolgerung: Prospektive Studien

  9. Hypertonic fluid administration in patients with septic shock: a prospective randomized controlled pilot study. (United States)

    van Haren, Frank M P; Sleigh, James; Boerma, E Christiaan; La Pine, Mary; Bahr, Mohamed; Pickkers, Peter; van der Hoeven, Johannes G


    We assessed the short-term effects of hypertonic fluid versus isotonic fluid administration in patients with septic shock. This was a double-blind, prospective randomized controlled trial in a 15-bed intensive care unit. Twenty-four patients with septic shock were randomized to receive 250 mL 7.2% NaCl/6% hydroxyethyl starch (HT group) or 500 mL 6% hydroxyethyl starch (IT group). Hemodynamic measurements included mean arterial blood pressure (MAP), central venous pressure, stroke volume index, stroke volume variation, intrathoracic blood volume index, gastric tonometry, and sublingual microcirculatory flow as assessed by sidestream dark field imaging. Systolic tissue Doppler imaging velocities of the medial mitral annulus were measured using echocardiography to assess left ventricular contractility. Log transformation of the ratio MAP divided by the norepinephrine infusion rate (log MAP/NE) quantified the combined effect on both parameters. Compared with the IT group, hypertonic solution treatment resulted in an improvement in log MAP/NE (P = 0.008), as well as an increase in systolic tissue Doppler imaging velocities (P = 0.03) and stroke volume index (P = 0.017). No differences between the groups were found for preload parameters (central venous pressure, stroke volume variation, intrathoracic blood volume index) or for afterload parameters (systemic vascular resistance index, MAP). Hypertonic solution treatment decreased the need for ongoing fluid resuscitation (P = 0.046). No differences between groups were observed regarding tonometry or the sublingual microvascular variables. In patients with septic shock, hypertonic fluid administration did not promote gastrointestinal mucosal perfusion or sublingual microcirculatory blood flow in comparison to isotonic fluid. Independent of changes in preload or afterload, hypertonic fluid administration improved the cardiac contractility and vascular tone compared with isotonic fluid. The need for ongoing fluid

  10. SU-E-T-457: Design and Characterization of An Economical 192Ir Hemi-Brain Small Animal Irradiator

    Energy Technology Data Exchange (ETDEWEB)

    Grams, M; Wilson, Z; Sio, T; Beltran, C; Tryggestad, E; Gupta, S; Blackwell, C; McCollough, K; Sarkaria, J; Furutani, K [Mayo Clinic, Rochester, MN (United States)


    Purpose: To describe the design and dosimetric characterization of a simple and economical small animal irradiator. Methods: A high dose rate 192Ir brachytherapy source from a commercially available afterloader was used with a 1.3 centimeter thick tungsten collimator to provide sharp beam penumbra suitable for hemi-brain irradiation of mice. The unit is equipped with continuous gas anesthesia to allow robust animal immobilization. Dosimetric characterization of the device was performed with Gafchromic film. The penumbra from the small animal irradiator was compared under similar collimating conditions to the penumbra from 6 MV photons, 6 MeV electrons, and 20 MeV electrons from a linear accelerator as well as 300 kVp photons from an orthovoltage unit and Monte Carlo simulated 90 MeV protons. Results: The tungsten collimator provides a sharp penumbra suitable for hemi-brain irradiation, and dose rates on the order of 200 cGy/minute were achieved. The sharpness of the penumbra attainable with this device compares favorably to those measured experimentally for 6 MV photons, and 6 and 20 MeV electron beams from a linear accelerator. Additionally, the penumbra was comparable to those measured for a 300 kVp orthovoltage beam and a Monte Carlo simulated 90 MeV proton beam. Conclusions: The small animal irradiator described here can be built for under $1,000 and used in conjunction with any commercial brachytherapy afterloader to provide a convenient and cost-effective option for small animal irradiation experiments. The unit offers high dose rate delivery and sharp penumbra, which is ideal for hemi-brain irradiation of mice. With slight modifications to the design, irradiation of sites other than the brain could be accomplished easily. Due to its simplicity and low cost, the apparatus described is an attractive alternative for small animal irradiation experiments requiring a sharp penumbra.

  11. Identifying early changes in myocardial microstructure in hypertensive heart disease. (United States)

    Hiremath, Pranoti; Bauer, Michael; Aguirre, Aaron D; Cheng, Hui-Wen; Unno, Kazumasa; Patel, Ravi B; Harvey, Bethany W; Chang, Wei-Ting; Groarke, John D; Liao, Ronglih; Cheng, Susan


    The transition from healthy myocardium to hypertensive heart disease is characterized by a series of poorly understood changes in myocardial tissue microstructure. Incremental alterations in the orientation and integrity of myocardial fibers can be assessed using advanced ultrasonic image analysis. We used a modified algorithm to investigate left ventricular myocardial microstructure based on analysis of the reflection intensity at the myocardial-pericardial interface on B-mode echocardiographic images. We evaluated the extent to which the novel algorithm can differentiate between normal myocardium and hypertensive heart disease in humans as well as in a mouse model of afterload resistance. The algorithm significantly differentiated between individuals with uncomplicated essential hypertension (N = 30) and healthy controls (N = 28), even after adjusting for age and sex (P = 0.025). There was a trend in higher relative wall thickness in hypertensive individuals compared to controls (P = 0.08), but no difference between groups in left ventricular mass (P = 0.98) or total wall thickness (P = 0.37). In mice, algorithm measurements (P = 0.026) compared with left ventricular mass (P = 0.053) more clearly differentiated between animal groups that underwent fixed aortic banding, temporary aortic banding, or sham procedure, on echocardiography at 7 weeks after surgery. Based on sonographic signal intensity analysis, a novel imaging algorithm provides an accessible, non-invasive measure that appears to differentiate normal left ventricular microstructure from myocardium exposed to chronic afterload stress. The algorithm may represent a particularly sensitive measure of the myocardial changes that occur early in the course of disease progression.

  12. Identifying early changes in myocardial microstructure in hypertensive heart disease.

    Directory of Open Access Journals (Sweden)

    Pranoti Hiremath

    Full Text Available The transition from healthy myocardium to hypertensive heart disease is characterized by a series of poorly understood changes in myocardial tissue microstructure. Incremental alterations in the orientation and integrity of myocardial fibers can be assessed using advanced ultrasonic image analysis. We used a modified algorithm to investigate left ventricular myocardial microstructure based on analysis of the reflection intensity at the myocardial-pericardial interface on B-mode echocardiographic images. We evaluated the extent to which the novel algorithm can differentiate between normal myocardium and hypertensive heart disease in humans as well as in a mouse model of afterload resistance. The algorithm significantly differentiated between individuals with uncomplicated essential hypertension (N = 30 and healthy controls (N = 28, even after adjusting for age and sex (P = 0.025. There was a trend in higher relative wall thickness in hypertensive individuals compared to controls (P = 0.08, but no difference between groups in left ventricular mass (P = 0.98 or total wall thickness (P = 0.37. In mice, algorithm measurements (P = 0.026 compared with left ventricular mass (P = 0.053 more clearly differentiated between animal groups that underwent fixed aortic banding, temporary aortic banding, or sham procedure, on echocardiography at 7 weeks after surgery. Based on sonographic signal intensity analysis, a novel imaging algorithm provides an accessible, non-invasive measure that appears to differentiate normal left ventricular microstructure from myocardium exposed to chronic afterload stress. The algorithm may represent a particularly sensitive measure of the myocardial changes that occur early in the course of disease progression.

  13. Rationale, design and methodology for Intraventricular Pressure Gradients Study: a novel approach for ventricular filling assessment in normal and falling hearts

    Directory of Open Access Journals (Sweden)

    Vouga Luís


    Full Text Available Abstract Background Intraventricular pressure gradients have been described between the base and the apex of the left ventricle during early diastolic ventricular filling, as well as, their increase after systolic and diastolic function improvement. Although, systolic gradients have also been observed, data are lacking on their magnitude and modulation during cardiac dysfunction. Furthermore, we know that segmental dysfunction interferes with the normal sequence of regional contraction and might be expected to alter the physiological intraventricular pressure gradients. The study hypothesis is that systolic and diastolic gradients, a marker of normal left ventricular function, may be related to physiological asynchrony between basal and apical myocardial segments and they can be attenuated, lost entirely, or even reversed when ventricular filling/emptying is impaired by regional acute ischemia or severe aortic stenosis. Methods/Design Animal Studies: Six rabbits will be completely instrumented to measuring apex to outflow-tract pressure gradient and apical and basal myocardial segments lengthening changes at basal, afterloaded and ischemic conditions. Afterload increase will be performed by abruptly narrowing or occluding the ascending aorta during the diastole and myocardial ischemia will be induced by left coronary artery ligation, after the first diagonal branch. Patient Studies: Patients between 65-80 years old (n = 12, both genders, with severe aortic stenosis referred for aortic valve replacement will be selected as eligible subjects. A high-fidelity pressure-volume catheter will be positioned through the ascending aorta across the aortic valve to measure apical and outflow-tract pressure before and after aortic valve replacement with a bioprosthesis. Peak and average intraventricular pressure gradients will be recorded as apical minus outflow-tract pressure and calculated during all diastolic and systolic phases of cardiac cycle

  14. In vitro evaluation of the load response characteristics of the total artificial heart with axial flow pumps%轴流泵式全人工心脏的体外测试及对负荷反应特性

    Institute of Scientific and Technical Information of China (English)

    李国荣; 朱晓东; 田步升; 陈海丰


    Objective To test the total artificial heart with axial flow pumps in a mock circuit, and explore the physiological basis of the control program. Methods The prototype of the total artificial heart was constructed by 2 axial flow pumps as substitute for the left and right heart pump respectively. The two blood pumps were housed in a rigid shell, with diameter of 65 mm and length of 70 mm. The performance of the total artificial heart was tested by concatenating the 2 axial flow pumps in a mock circuit. Results When the preload was fixed, the cardiac output was gradually decreased with the increase in afterload. The inhibitory effect of the afterload on cardiac output was attenuated by increasing the pump flow rate. In the current study, the speed of the left and right pumps were set at 11 000 r/min and 8 500 r/min respectively, which led to a flow rate of 5 Umin against 13.3 kPa(100 mmHg)after load. However, when the afterload increased to 26.7 kPa(200 mmHg), the flow rate dropped to 0. Improved pump speed could effectively compensate this trend and the increase in preload did not obviously affect the output of artificial heart when the afterload was fixed. It was ohserved that when the preload was changed from 0.27 kPa(2 mmHg) to 1.87 kPa(14 mmHg), the output of the total artificial heart maintained at 7 L/min. Conclusion It is demonstrated that the cardiac output of the artificial heart is significantly restrained by the afterload while the preload exhibited little influence on it. Further investigation is needed to explore the significance of the difference in the load response characteristic between the artificial heart employed in the current study and the natural heart.%目的 在体外模拟循环台测试轴流泵式全人工心脏的基本负荷反应特性,为探索生理性控制方案提供基础.方法 轴流泵式全人工心脏样机采用2个轴流泵共同设置在刚性外壳中,直径65mm,长度70mm.于模拟循环台

  15. The relationship of pulmonary vascular resistance and compliance to pulmonary artery wedge pressure during submaximal exercise in healthy older adults (United States)

    Wright, Stephen P.; Granton, John T.; Esfandiari, Sam; Goodman, Jack M.


    Key points A consistent inverse hyperbolic relationship has been observed between pulmonary vascular resistance and compliance, although changes in pulmonary artery wedge pressure (PAWP) may modify this relationship.This relationship predicts that pulmonary artery systolic, diastolic and mean pressure maintain a consistent relationship relative to the PAWP.We show that, in healthy exercising human adults, both pulmonary vascular resistance and compliance decrease in relation to exercise‐associated increases in PAWP.Pulmonary artery systolic, diastolic and mean pressures maintain a consistent relationship with one another, increasing linearly with increasing PAWP.Increases in PAWP in the setting of exercise are directly related to a decrease in pulmonary vascular compliance, despite small decreases in pulmonary vascular resistance, thereby increasing the pulsatile afterload to the right ventricle. Abstract The resistive and pulsatile components of right ventricular afterload (pulmonary vascular resistance, Rp; compliance, Cp) are related by an inverse hyperbolic function, expressed as their product known as RpCp‐time. The RpCp‐time exhibits a narrow range, although it may be altered by the pulmonary artery wedge pressure (PAWP). Identifying the determinants of RpCp‐time should improve our understanding of the physiological behaviour of pulmonary arterial systolic (PASP), diastolic (PADP) and mean (mPAP) pressures in response to perturbations. We examined the effect of exercise in 28 healthy non‐athletic adults (55 ± 6 years) who underwent right heart catheterization to assess haemodynamics and calculate Rp and Cp. Measurements were made at rest and during two consecutive 8–10 min stages of cycle ergometry, at targeted heart‐rates of 100 beats min–1 (Light) and 120 beats min–1 (Moderate). Cardiac output increased progressively during exercise. PASP, PADP, mPAP and PAWP increased for Light exercise, without any further rise for Moderate

  16. Low-Level Laser Application in the Early Myocardial Infarction Stage Has No Beneficial Role in Heart Failure (United States)

    Manchini, Martha T.; Antônio, Ednei L.; Silva Junior, José Antônio; de Carvalho, Paulo de Tarso C.; Albertini, Regiane; Pereira, Fernando C.; Feliciano, Regiane; Montemor, Jairo; Vieira, Stella S.; Grandinetti, Vanessa; Yoshizaki, Amanda; Chaves, Marcio; da Silva, Móises P.; de Lima, Rafael do Nascimento; Bocalini, Danilo S.; de Melo, Bruno L.; Tucci, Paulo J. F.; Serra, Andrey J.


    Low-level laser therapy (LLLT) has been targeted as a promising approach that can mitigate post-infarction cardiac remodeling. There is some interesting evidence showing that the beneficial role of the LLLT could persist long-term even after the end of the application, but it remains to be systematically evaluated. Therefore, the present study aimed to test the hypothesis that LLLT beneficial effects in the early post-infarction cardiac remodeling could remain in overt heart failure even with the disruption of irradiations. Female Wistar rats were subjected to the coronary occlusion to induce myocardial infarction or Sham operation. A single LLLT application was carried out after 60 s and 3 days post-coronary occlusion, respectively. Echocardiography was performed 3 days and at the end of the experiment (5 weeks) to evaluate cardiac function. After the last echocardiographic examination, LV hemodynamic evaluation was performed at baseline and on sudden afterload increases. Compared with the Sham group, infarcted rats showed increased systolic and diastolic internal diameter as well as a depressed shortening fraction of LV. The only benefit of the LLLT was a higher shortening fraction after 3 days of infarction. However, treated-LLLT rats show a lower shortening fraction in the 5th week of study when compared with Sham and non-irradiated rats. A worsening of cardiac function was confirmed in the hemodynamic analysis as evidenced by the higher LV end-diastolic pressure and lower +dP/dt and −dP/dt with five weeks of study. Cardiac functional reserve was also impaired by infarction as evidenced by an attenuated response of stroke work index and cardiac output to a sudden afterload stress, without LLLT repercussions. No significant differences were found in the myocardial expression of Akt1/VEGF pathway. Collectively, these findings illustrate that LLLT improves LV systolic function in the early post-infarction cardiac remodeling. However, this beneficial effect may

  17. [Non invasive quantification of the parietal systolic stress of the left ventricle in patients with heart failure and its clinical application]. (United States)

    Guadalajara Boo, José Fernando; González Zárate, Jaime; Bucio Reta, Eduardo; Pérez, Patricia; Cué Carpio, Ramón José


    The purpose of this study is to calculate non invasivelly left ventricular systolic wall stress by echocardiography in patients with primary heart failure, and compare the results with those obtained in parients with overloaded heart failure, diastolic dysfunction by Inapropiatte hypertrophy, with normal ejection fraction and people with normal heart, there stablish the value of the results in clinical settings. We studied 33 patients with heart failure by dilated cardiomyopathy. There was no significant association between the systolic wall stress and the ejection fraction, fractional shortening, dp/dt or left ventricular mass in this group of study. There was a significant association between systolic h/r ratio and the systolic wall stress. This study shows that in primary heart failure the afterload increases and has inverse relationship with ejection fraction (r = 0.86); but, when heart failure obey to an excessive overload exists an exquisite inverse relationship between systolic wall stress and ejection fraction (r = 0.93). The excessive hypertrophy (Inappropriate) reduces the systolic wall stress but causes diastolic dysfunction. The increase of systolic wall stress in Aortic regurgitation with normal ventricular performance is responsible of adequate left ventricular hypertrophy, by other means, in mitral insufficiency the presence of low or normal systolic wall The purpose of this study is to calculate non invasivelly left ventricular systolic wall stress by echocardiography in patients with primary heart failure, and compare the results with those obtained in parients with overloaded heart failure, diastolic dysfunction by Inapropiatte hypertrophy, with normal ejection fraction and people with normal heart, there stablish the value of the results in clinical settings. We studied 33 patients with heart failure by dilated cardiomyopathy. There was no significant association between the systolic wall stress and the ejection fraction, fractional shortening

  18. Dedicated high dose rate 192Ir brachytherapy radiation fields for in vitro cell exposures at variable source-target cell distances: killing of mammalian cells depends on temporal dose rate fluctuation (United States)

    Veigel, Cornelia; Hartmann, Günther H.; Fritz, Peter; Debus, Jürgen; Weber, Klaus-Josef


    Afterloading brachytherapy is conducted by the stepwise movement of a radioactive source through surgically implanted applicator tubes where at predefined dwell positions calculated dwell times optimize spatial dose delivery with respect to a planned dose level. The temporal exposure pattern exhibits drastic fluctuations in dose rate at a given coordinate and within a single treatment session because of the discontinuous and repeated source movement into the target volume. This could potentially affect biological response. Therefore, mammalian cells were exposed as monolayers to a high dose rate 192Ir source by utilizing a dedicated irradiation device where the distance between a planar array of radioactive source positions and the plane of the cell monolayer could be varied from 2.5 mm to 40 mm, thus varying dose rate pattern for any chosen total dose. The Gammamed IIi afterloading system equipped with a nominal 370 GBq (10 Ci) 192-Ir source was used to irradiate V79 Chinese hamster lung fibroblasts from both confluent and from exponential growth phase with dose up to 12 Gy (at room temperature, total exposure not exceeding 1 h). For comparison, V79 cells were also exposed to 6 MV x-rays from a clinical linear accelerator (dose rate of 2.5 Gy min‑1). As biological endpoint, cell survival was determined by standard colony forming assay. Dose measurements were conducted with a diamond detector (sensitive area 7.3 mm2), calibrated by means of 60Co radiation. Additionally, dose delivery was simulated by Monte Carlo calculations using the EGSnrc code system. The calculated secondary electron fluence spectra at the cell location did not indicate a significant change of radiation quality (i.e. higher linear energy transfer) at the lower distances. Clonogenic cell survival curves obtained after brachytherapy exhibited an altered biological response compared to x-rays which was characterized by a significant reduction of the survival curve shoulder when dose rate

  19. Noninvasive ventilation in patients with acute cardiogenic pulmonary edema

    Directory of Open Access Journals (Sweden)

    Andrea Bellone


    Full Text Available The term noninvasive ventilation (NIV encompasses two different modes of delivering positive airway pressure, namely continuous positive airway pressure (CPAP and bilevel positive airway pressure (bilevel-PAP. The two modes are different since CPAP does not actively assist inspiration whereas bilevel-PAP does. Bilevel-PAP is a type of noninvasive ventilation that helps keep the upper airways of the lungs open by providing a flow of air delivered through a face mask. The air is pressurized by a machine, which delivers it to the face mask through long, plastic hosing. With bilevel-PAP, the doctor prescribes specific alternating pressures: a higher pressure is used to breathe in (inspiratory positive airway pressure and a lower pressure is used to breath out (expiratory positive airway pressure. Noninvasive ventilation has been shown to reduce the rate of tracheal intubation. The main indications are exacerbation of chronic obstructive pulmonary disease and acute cardiogenic pulmonary edema (ACPE. This last is a common cause of respiratory failure with high incidence and high mortality rate. Clinical findings of ACPE are related to the increased extra-vascular water in the lungs and the resulting reduced lung compliance, increased airway resistance and elevated inspiratory muscle load which generates a depression in pleural pressure. These large pleural pressure swings are responsible for hemodynamic changes by increasing left ventricular afterload, myocardial transmural pressure, and venous return. These alterations can be detrimental to patients with left ventricular systolic dysfunction. Under these circumstances, NIV, either by CPAP or bilevel-PAP, improves vital signs, gas exchange, respiratory mechanics and hemodynamics by reducing left ventricular afterload and preload. In the first randomized study which compared the effectiveness of CPAP plus medical treatment vs medical treatment alone, the CPAP group showed a significant decrease in its

  20. Quinapril therapy in patients with chronic mitral regurgitation. (United States)

    Schön, H R; Schröter, G; Barthel, P; Schömig, A


    Pre- and afterload reduction is known to have beneficial effects in patients with chronic mitral regurgitation. To date, no controlled study has been reported analyzing the long term influence of angiotensin-converting enzyme inhibitor treatment on patients with chronic mitral regurgitation. Therefore the aim of this study was to assess the effects of one year angiotensin-converting enzyme inhibition with quinapril on myocardial performance in patients with chronic mitral regurgitation. Twelve patients with moderate to severe isolated chronic mitral regurgitation and no coronary disease on coronary angiography were studied under control conditions and followed up until one year of quinapril therapy (10-20mg/day) using echocardiography and simultaneous right heart catheterization, and radionuclide ventriculography at rest and exercise. As the result of a significant pre- and afterload reduction after one year quinapril treatment regurgitant fraction fell from 0.43 +/- 0.10 at control before therapy to 0.25 +/- 0.08 (p = 0.0001), left ventricular end-diastolic volume was reduced from 146 +/- 26 to 109 +/- 24 ml/m2 (p = 0.0001) and end-systolic volume decreased from 63 +/- 43 to 47 +/- 29 ml/m2 (p = 0.02). Left ventricular ejection fraction at control averaged 0.59 +/- 0.20 at rest, increased to 0.65 +/- 0.21 with maximum exercise and was unchanged after one year quinapril therapy. After one year treatment left ventricular mass was reduced by 15% (p = 0.0004) and septal wall thickness decreased from 11.8 +/- 0.7 to 10.8 +/- 0.8 mm (p = 0.0006). Moreover, there was significant functional improvement of nearly one NYHA class after one year quinapril therapy. In conclusion, in patients with chronic mitral regurgitation long term angiotensin-converting enzyme inhibition with quinapril reduces regurgitation and decreases left ventricular size and mass thereby demonstrating functional improvement. In addition, these data suggest that angiotensin-converting enzyme inhibition

  1. A new look at bronchopulmonary dysplasia: postcapillary pathophysiology and cardiac dysfunction (United States)

    Malikiwi, Andra; Paul, Eldho; Tan, Kenneth; Menahem, Samuel


    Abstract Pulmonary hypertension (PH) and right ventricular function are the focus of cardiovascular effects of bronchopulmonary dysplasia (BPD). We assessed cardiac indexes reflecting systemic afterload and pulmonary venous back pressure as pathophysiologic factors. Cardiac parameters were measured by conventional echocardiography in 20 preterm infants with severe BPD and compared with those of 10 preterm infants with no BPD and 20 healthy term infants. In infants with severe BPD, PH was noted in 5 (25%) by tricuspid regurgitation Doppler jet ≥2.8 m/s and in 15 (75%) by time to peak velocity/right ventricular ejection time valve stroke volume (4.7 ± 0.7 vs. 5.6 ± 0.6 vs. 5.9 ± 0.1; P = 0.002), and myocardial performance index (0.33 ± 0.05 vs. 0.28 ± 0.01 vs. 0.27 ± 0.05; P = 0.03). Left ventricular output was significantly lower in the BPD cohort (183 ± 45 vs. 189 ± 9 vs. 191 ± 32 mL/kg/min; P = 0.03). Altered systemic (left-sided) cardiac function was noted in infants with BPD, which may lead to pulmonary venous congestion contributing to a continued need for respiratory support. PMID:28090292

  2. Doppler echocardiographic study in adolescents and young adults with sickle cell anemia

    Directory of Open Access Journals (Sweden)

    Wolney de Andrade Martins


    Full Text Available OBJECTIVE: Anatomical and functional assessment of the heart through Doppler and echocardiography in patients with cell anemia (SCA. METHODS: Twenty-five patients with SCA and ages ranging from 14 to 45 years were prospectively studied in a comparison with 25 healthy volunteers. All of them underwent clinical and laboratory evaluation and Doppler echocardiography as well.The measurements were converted into body surface indices. RESULTS: There were increases in all chamber diameters and left ventricle (LV mass of the SCA patients. It was characterised an eccentric hypertrophy of the left ventricle. The preload was increased (left ventricle end-diastolic volume and the afterload was decreased (diastolic blood pressure, peripheral vascular resistance and end-systolic parietal stress ESPS. The cardiac index was increased due to the stroke volume. The ejection fraction and the percentage of the systolic shortening , as well as the systolic time intervals of the LV were equivalent. The isovolumetric contraction period of the LV was increased. The mitral E-septum distance and the end-systolic volume index (ESVi were increased. The ESPS/ESVi ratio,a loading independent parameter, was decreased in SCA, suggesting systolic dysfunction. No significant differences in the diastolic function or in the pulmonary pressure occurred. CONCLUSION: Chamber dilations, eccentric hypertrophy and systolic dysfunction confirm the evidence of the literature in characterizing a sickle cell anemia cardiomyopathy.

  3. Right Ventricular Adaptation Is Associated with the Glu298Asp Variant of the NOS3 Gene in Elite Athletes. (United States)

    Szelid, Zsolt; Lux, Árpád; Kolossváry, Márton; Tóth, Attila; Vágó, Hajnalka; Lendvai, Zsuzsanna; Kiss, Loretta; Maurovich-Horvat, Pál; Bagyura, Zsolt; Merkely, Béla


    Nitric oxide (NO), an important endogenous pulmonary vasodilator is synthetized by the endothelial NO synthase (NOS3). Reduced NO bioavailability and thus the Glu298Asp polymorphism of NOS3 may enhance right ventricular (RV) afterload and hypertrophic remodeling and influence athletic performance. To test this hypothesis world class level athletes (water polo players, kayakers, canoeists, rowers, swimmers, n = 126) with a VO2 maximum greater than 50ml/kg/min were compared with non-athletic volunteers (n = 155). Cardiopulmonary exercise tests and cardiac magnetic resonance imaging (cMRI) were performed to determine structural or functional changes. Genotype distribution of the NOS3 Glu298Asp polymorphism was not affected by gender or physical performance. Cardiac MRI showed increased stroke volume with eccentric hypertrophy in all athletes regardless of their genotype. However, the Asp allelic variant carriers had increased RV mass index (32±6g versus 27±6g, pgene function and NO bioavailability in sport related cardiac adaptation.

  4. [New frontiers in myocardial preservation]. (United States)

    Juffe Stein, A


    The high hospital mortality due to primary graft failure, together with the ever more frequent use of "Suboptimum" donors because of the scarcity of organs has, in the recent years, caused renewed interest in perfectioning techniques of cardiac preservation. The numerous studies supporting the benefits of a period of controlled warm reperfusion after global ischemia, and the growth of the continuous warm blood cardioplegia, led us to the evolution of our own technique for myocardial protection during transplantation. Dr John Wallwork introduced the concept of donor "resuscitation" in the attempt to improve the hemodynamic state of the donor, by preload and afterload manipulation and pharmacological treatment of the unstable or "marginal" donor. The Juan Canalejo Hospital introduced the concept "Resuscitation during the implantation" using continuous warm blood cardioplegia. Maintenance of normothermia during heart transplantation produces what is referred to as "cell repair" or "resuscitation during the implantation" and avoid the reperfusion damage. From january 1992 to april 1995, 91 orthotopic heart transplantation were performed at our institution. By harvesting we have employed the conventional preservation technique. We performed a controlled continuous anterograde/retrograde warm blood cardioplegic reperfusion of the graft, before and during the implantation in 53 patients. Since january 1994 we performed in 38 cases the same controlled continuous warm blood reperfusion, but only anterograde. Continuous warm blood cardioplegia in heart transplantation is a safety myocardial protection method. Trasplant programs require the optimal use of the available donors.

  5. Three-dimensional brachytherapy optimization techniques in the treatment of patients with cervix cancer; Apport des techniques de curietherapie optimisee grace a l'imagerie tridimensionnelle dans la prise en charge des patientes atteintes d'un cancer du col uterin

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    Haie-Meder, C.; Mazeron, R.; Verezesan, O.; Monnier, L.; Vieillot, S. [Institut Gustave-Roussy, Service de Curietherapie, 94 - Villejuif (France); Dumas, I. [Institut Gustave-Roussy, Service de Physique, 94 - Villejuif (France); Lhomme, C. [Institut Gustave-Roussy, Service d' Ooncologie Gynecologique, 94 - Villejuif (France); Morice, P. [Institut Gustave-Roussy, Service de Chirurgie Oncologique, 94 - Villejuif (France); Barillot, I. [Centre Regional Universitaire de Cancerologie Henry-S.-Kaplan, Hopital Bretonneau, CHU de Tours, 37 - Tours (France); Universite Francois-Rabelais, 37 - Tours (France)


    Traditionally, prescription and treatment planning in intracavitary brachytherapy for cervix cancer have used either reference points (mainly points A and B) or reference isodoses (60 Gy according to ICRU recommendations) to report doses to the target volume. Doses to critical organs were reported at bladder and rectum ICRU points. This practice has been supported by a long-standing clinical experience that has yielded an acceptable therapeutic ratio. The recent development of imaging has contributed to the improvement in target and organs at risk knowledge. In 2005 and 2006, the European group of brachytherapy -European Society for therapeutic radiology and oncology (GEC-E.S.T.R.O.) recommendations publications on 3-D based image brachytherapy have defined the different volumes of interest. These recommendations have been validated with intercomparison delineation studies. With the concomitant development of remote after-loading projectors, provided with miniaturized sources, it is now possible to plan radiation doses by adjusting dwell positions and relative dwell time values. These procedures allow better coverage of the targets while sparing O.A.R.. The recent literature data evidence a significant improvement in local control with no increase in complications. Further studies are needed to better define the dose recommended in both tumour and organs at risk. This is one of the goals of the European study on MRI-guided brachytherapy in locally advanced cervical cancer (E.M.B.R.A.C.E.) protocol (meaning of acronym: an international study on MRI-guided brachytherapy in locally advanced cervical cancer). (authors)

  6. Paroxysmal Atrial Fibrillation in the Course of Acute Pulmonary Embolism: Clinical Significance and Impact on Prognosis

    Directory of Open Access Journals (Sweden)

    Agnieszka Krajewska


    Full Text Available The relationship and clinical implications of atrial fibrillation (AF in acute pulmonary embolism (PE are poorly investigated. We aimed to analyze clinical characteristics and prognosis in PE patients with paroxysmal AF episode. Methods. From the 391 patients with PE 31 subjects with paroxysmal AF were selected. This group was compared with patients with PE and sinus rhythm (SR and 32 patients with PE and permanent AF. Results. Paroxysmal AF patients were the oldest. Concomitant DVT varies between groups: paroxysmal AF 32.3%, SR 49.5%, and permanent AF 28.1% (p=0.02. The stroke history frequency was 4.6% SR, 12.9% paroxysmal AF, and 21.9% permanent AF (p<0.001. Paroxysmal AF comparing to permanent AF and SR individuals had higher estimated SPAP (56 versus 48 versus 47 mmHg, p=0.01 and shorter ACT (58 versus 65 versus 70 ms, p=0.04. Patients with AF were more often classified into high-risk group according to revised Geneva score and sPESI than SR patients. In-hospital mortality was lower in SR (5% and paroxysmal AF (6.5% compared to permanent AF group (25% (p<0.001. Conclusions. Patients with PE-associated paroxysmal AF constitute a separate population. More severe impairment of the parameters reflecting RV afterload may indicate relation between PE severity and paroxysmal AF episode. Paroxysmal AF has no impact on short-term mortality.

  7. Mammalian pharmacology of the fish neuropeptide urotensin I. (United States)

    MacCannell, K L; Lederis, K


    The urophysis, a neurosecretory organ in fish, contains a number of putative hormones, collectively called urotensins. One of these, urotensin I--a straight chain peptide of 38 amino acids--produces a sustained hypotensive action in all mammalian species examined. In the anesthetized dog, the hypotensive action of native urotensin I is due to specific dilatation of the mesenteric vascular bed, the peptide having no significant actions on other vascular beds. Recent work has established that urotensin I is similar in structure to sauvagine and ovine corticotropin-releasing factor (CRF). Synthetic urotensin I and synthetic sauvagine both share the ability of synthetic ovine CRF to release adrenocorticotropin from cultured pituitary cells. All these synthetic peptides appear to lower blood pressure in the dog by the mechanism established for native urotensin I: selective mesenteric vasodilatation. The selectivity of the mesenteric vascular response suggests that a similar endogenous peptide might be the physiological regulator of gut blood flow. These peptides, or analogs, may also prove to be of value in ischemic bowel disease or anastomotic gastrointestinal surgery, or in reduction of afterload in heart failure.

  8. [The thickness/radius ratio (h/r) of the left ventricle in pure mitral insufficiency]. (United States)

    Guadalajara, J F; Alexánderson, E; Monobe, F; Nieto, S; Huerta, D


    We studied 11 patients with severe mitral regurgitation (MR). With 2-D echocardiogram we could obtain the septal and posterior wall thickness, left ventricular internal dimensions and ventricular function. With parasternal short axis view we calculate the h/r ratio (left ventricular thickness/radius). The results were compared with normal values: we found important left atrial and ventricle dilatation with significative difference from the normal values (P < 0.001), the diastolic and systolic h/r ratio was significative lower than the normal values (P < 0.005): the systolic wall stress was significative higher in relation to normal values (P < 0.001). We conclude that patients with severe (MR) initially have an important ventricular dilatation but no hypertrophy despite volume overload. The possible explanation is that in early stages of the disease, the afterload of the left ventricle is low and does not trigger the development of hypertrophy. The hypertrophy appears only when the systolic stress is high secondary to myocardial failure. The excessive dilatation of the left ventricle probably damages the myocardial fibers by excessive stretch. This mechanism probably explains the poor late surgical evolution of patients with mitral prosthesis. This we propose that the optimal surgical timing for such patients is when the systolic wall stress elevates over the normal limits, because this is an early sign of myocardial failure.

  9. A hyperkinetic heart in uncomplicated active acromegaly. Explanation of hypertension in acromegalic patients? (United States)

    Thuesen, L; Christensen, S E; Weeke, J; Orskov, H; Henningsen, P


    Cardiac function was studied by echocardiography in 12 patients with active acromegaly and in 12 age- and sex-matched healthy control subjects. None of the patients had cardiovascular diseases or other endocrine diseases than acromegaly. The patients had a mean age of 39 +/- 5 years and were short-term acromegalic with a mean duration of disease of 6 +/- 3 years. Mean left ventricular mass was 163 +/- 43 g/m2 in the acromegalic group versus 120 +/- 24 g/m2 in the control group. Preload (the diastolic diameter of the left ventricle) was within normal limits, while afterload (end-systolic meridional wall stress) was significantly decreased in the acromegalic group. Myocardial contractility assessed as fractional shortening of the left ventricle was 39.9 +/- 3.6% in the acromegalic group versus 32.9 +/- 5.1% in the control group, and cardiac output was increased by 52% in the acromegalic group because of increased heart rate and stroke volume. We suggest that augmented peripheral blood flow is responsible for the condition of cardiac hyperkinesia in short-term acromegaly and involved in the development of hypertension, which is a frequent complication of long-term acromegaly.

  10. The fetal circulation. (United States)

    Kiserud, Torvid; Acharya, Ganesh


    Accumulating data on the human fetal circulation shows the similarity to the experimental animal physiology, but with important differences. The human fetus seems to circulate less blood through the placenta, shunt less through the ductus venosus and foramen ovale, but direct more blood through the lungs than the fetal sheep. However, there are substantial individual variations and the pattern changes with gestational age. The normalised umbilical blood flow decreases with gestational age, and, at 28 to 32 weeks, a new level of development seems to be reached. At this stage, the shunting through the ductus venosus and the foramen ovale reaches a minimum, and the flow through the lungs a maximum. The ductus venosus and foramen ovale are functionally closely related and represent an important distributional unit for the venous return. The left portal branch represents a venous watershed, and, similarly, the isthmus aorta an arterial watershed. Thus, the fetal central circulation is a very flexible and adaptive circulatory system. The responses to increased afterload, hypoxaemia and acidaemia in the human fetus are equivalent to those found in animal studies: increased ductus venosus and foramen ovale shunting, increased impedance in the lungs, reduced impedance in the brain, increasingly reversed flow in the aortic isthmus and a more prominent coronary blood flow.

  11. The Influence of Normal and Early Vascular Aging on Hemodynamic Characteristics in Cardio- and Cerebrovascular Systems. (United States)

    Yu, Hongtao; Huang, George P; Yang, Zifeng; Liang, Fuyou; Ludwig, Bryan


    Age-associated alterations in cardiovascular structure and function induce cardiovascular disease in elderly subjects. To investigate the effects of normal vascular aging (NVA) and early vascular aging (EVA) on hemodynamic characteristics in the circle of Willis (CoW), a closed-loop one-dimensional computational model was developed based on fluid mechanics in the vascular system. The numerical simulations revealed that higher central pulse pressure and augmentation index (AIx) appear in the EVA subjects due to early arrival of reflected waves, resulted in the increase of cardiac afterload compared with the NVA subjects. Moreover, the hemodynamic characteristics in the CoW show that the EVA subjects in an older age display a higher blood pressure than that of the NVA with a complete CoW. Herein, the increased blood pressure and flow rate coexist in the subjects with an incomplete CoW. In conclusion, the hemodynamic characteristics in the aortic tree and CoW related to aging appear to play an important role in causing cardiovascular and intravascular disease.

  12. Effects of Curcumin on Parameters of Myocardial Oxidative Stress and of Mitochondrial Glutathione Turnover in Reoxygenation after 60 Minutes of Hypoxia in Isolated Perfused Working Guinea Pig Hearts

    Directory of Open Access Journals (Sweden)

    Ermita I. Ibrahim Ilyas


    Full Text Available In cardiovascular surgery ischemia-reperfusion injury is a challenging problem, which needs medical intervention. We investigated the effects of curcumin on cardiac, myocardial, and mitochondrial parameters in perfused isolated working Guinea pig hearts. After preliminary experiments to establish the model, normoxia was set at 30 minutes, hypoxia was set at 60, and subsequent reoxygenation was set at 30 minutes. Curcumin was applied in the perfusion buffer at 0.25 and 0.5 μM concentrations. Cardiac parameters measured were afterload, coronary and aortic flows, and systolic and diastolic pressure. In the myocardium histopathology and AST in the perfusate indicated cell damage after hypoxia and malondialdehyde (MDA levels increased to 232.5% of controls during reoxygenation. Curcumin protected partially against reoxygenation injury without statistically significant differences between the two dosages. Mitochondrial MDA was also increased in reoxygenation (165% of controls, whereas glutathione was diminished (35.2% as well as glutathione reductase (29.3%, which was significantly increased again to 62.0% by 0.05 μM curcumin. Glutathione peroxidase (GPx was strongly increased in hypoxia and even more in reoxygenation (255% of controls. Curcumin partly counteracted this increase and attenuated GPx activity independently in hypoxia and in reoxygenation, 0.25 μM concentration to 150% and 0.5 μM concentration to 200% of normoxic activity.

  13. Renal dopamine receptors and hypertension. (United States)

    Hussain, Tahir; Lokhandwala, Mustafa F


    Dopamine has been recognized as an important modulator of central as well as peripheral physiologic functions in both humans and animals. Dopamine receptors have been identified in a number of organs and tissues, which include several regions within the central nervous system, sympathetic ganglia and postganglionic nerve terminals, various vascular beds, the heart, the gastrointestinal tract, and the kidney. The peripheral dopamine receptors influence cardiovascular and renal function by decreasing afterload and vascular resistance and promoting sodium excretion. Within the kidney, dopamine receptors are present along the nephron, with highest density on proximal tubule epithelial cells. It has been reported that there is a defective dopamine receptor, especially D(1) receptor function, in the proximal tubule of various animal models of hypertension as well as in humans with essential hypertension. Recent reports have revealed the site of and the molecular mechanisms responsible for the defect in D(1) receptors in hypertension. Moreover, recent studies have also demonstrated that the disruption of various dopamine receptor subtypes and their function produces hypertension in rodents. In this review, we present evidence that dopamine and dopamine receptors play an important role in regulating renal sodium excretion and that defective renal dopamine production and/or dopamine receptor function may contribute to the development of various forms of hypertension.

  14. Right ventricular failure due to chronic pressure load: What have we learned in animal models since the NIH working group statement? (United States)

    Borgdorff, Marinus A J; Dickinson, Michael G; Berger, Rolf M F; Bartelds, Beatrijs


    Right ventricular (RV) failure determines outcome in patients with pulmonary hypertension, congenital heart diseases and in left ventricular failure. In 2006, the Working Group on Cellular and Molecular Mechanisms of Right Heart Failure of the NIH advocated the development of preclinical models to study the pathophysiology and pathobiology of RV failure. In this review, we summarize the progress of research into the pathobiology of RV failure and potential therapeutic interventions. The picture emerging from this research is that RV adaptation to increased afterload is characterized by increased contractility, dilatation and hypertrophy. Clinical RV failure is associated with progressive diastolic deterioration and disturbed ventricular-arterial coupling in the presence of increased contractility. The pathobiology of the failing RV shows similarities with that of the LV and is marked by lack of adequate increase in capillary density leading to a hypoxic environment and oxidative stress and a metabolic switch from fatty acids to glucose utilization. However, RV failure also has characteristic features. So far, therapies aiming to specifically improve RV function have had limited success. The use of beta blockers and sildenafil may hold promise, but new therapies have to be developed. The use of recently developed animal models will aid in further understanding of the pathobiology of RV failure and development of new therapeutic strategies.

  15. Effects of ryanodine on cardiac contraction, excitation-contraction coupling and "Treppe" in the conscious dog. (United States)

    Kalthof, B; Sato, N; Iwase, M; Shen, Y T; Mirsky, I; Patrick, T A; Vatner, S F


    The effects of ryanodine on left ventricular (LV) function and hemodynamics were studied in 16 conscious dogs, chronically instrumented for measurements of LV pressures and dimensions. Systemic infusion of ryanodine (0.5-4 micrograms/kg i.v.) resulted in a dose-dependent depression of cardiac contraction. For example, ryanodine, 4 micrograms/kg i.v., decreased LV fractional shortening by 30.5 +/- 4.1%, LV dP/dt by 41.5 +/- 4.0% and Vcfc by 37.8 +/- 4.1%, while increasing the isovolumic relaxation time constant, tau, from 23.1 +/- 1.4 to 34.1 +/- 3.6 ms without a major effect on preload or afterload. Ryanodine also depressed (P Treppe") was significantly enhanced (P Treppe" in the conscious dog under the condition of impaired SR calcium release caused by ryanodine, supports the concept that the classical Bowditch "Treppe" reflects either a state of myocardial depression due to alteration in SR calcium handling, or enhanced availability of trans-sarcolemmal Ca2+ influx. This finding may help to understand the discrepancy in the importance of the "Treppe" between conscious animals and more isolated preparations.

  16. Medical management of ischemic heart disease. (United States)

    Timmis, G C


    Medical therapy primarily affects myocardial oxygen demands. Nitrates and other vasodilators decrease filling pressure, ventricular diastolic volume and to some extent, impedance to ventricular emptying. Beta blockers decrease myocardial contractility and heart rate through a reduction of sympathetic neural traffic. Afterload reduction by the control of hypertension and preload reduction via the LaPlace relationship through reversal of congestive failure are critical for successful therapy. Modification of smoking habits and personality traits with renunciation of a sedentary life-style are also therapeutically useful. While increases in myocardial blood flow have depended primarily on surgical revascularization procedures, calcium antagonists such as nifedipine have been shown to affect flow by reversing vasospasm, which has been recognized with increasing frequency as a concomitant of even fixed coronary arterial disease. The first therapy, however, is diet since it affects both the supply and demand sides of myocardial oxygen balance. Reduction of body bulk decreases myocardial oxygen demand since both vary in obligate parallel. Religious abstention from saturated fats and cholesterol-containing foods, especially by those with pre-existing coronary heart disease, may arrest the otherwise inexorable deterioration.

  17. Axial and centrifugal continuous-flow rotary pumps: a translation from pump mechanics to clinical practice. (United States)

    Moazami, Nader; Fukamachi, Kiyotaka; Kobayashi, Mariko; Smedira, Nicholas G; Hoercher, Katherine J; Massiello, Alex; Lee, Sangjin; Horvath, David J; Starling, Randall C


    The recent success of continuous-flow circulatory support devices has led to the growing acceptance of these devices as a viable therapeutic option for end-stage heart failure patients who are not responsive to current pharmacologic and electrophysiologic therapies. This article defines and clarifies the major classification of these pumps as axial or centrifugal continuous-flow devices by discussing the difference in their inherent mechanics and describing how these features translate clinically to pump selection and patient management issues. Axial vs centrifugal pump and bearing design, theory of operation, hydrodynamic performance, and current vs flow relationships are discussed. A review of axial vs centrifugal physiology, pre-load and after-load sensitivity, flow pulsatility, and issues related to automatic physiologic control and suction prevention algorithms is offered. Reliability and biocompatibility of the two types of pumps are reviewed from the perspectives of mechanical wear, implant life, hemolysis, and pump deposition. Finally, a glimpse into the future of continuous-flow technologies is presented.

  18. Tolvaptan and its potential in the treatment of hyponatremia

    Directory of Open Access Journals (Sweden)

    Y Howard Lien


    Full Text Available Megan B Dixon, Y Howard LienDepartment of Medicine, University of Arizona, Arizona Kidney Disease and Hypertension Center, Tucson, Arizona, USAAbstract: Tolvaptan is a selective arginine vasopressin (AVP V2 receptor blocker used to induce free water diuresis in the treatment of euvolemic or hypervolemic hyponatremia. Currently the orally active medication is in the final stages prior to approval by the FDA for outpatient therapy. It appears to be safe and effective at promoting aquaresis and raising serum sodium levels in both short- and long-term studies. Tolvaptan is also effective for treatment of congestive heart failure (CHF exacerbation, but whether there are long standing beneficial effects on CHF is still controversial. Prolonged use of tolvaptan leads to increased endogenous levels of AVP and perhaps over-stimulation of V1A receptors. Theoretically this activation could lead to increased afterload and cardiac myocyte fibrosis, causing progression of CHF. However, after 52 weeks of tolvaptan therapy there was no worsening of left ventricular dilatation. In addition, tolvaptan is metabolized by the CYP3A4 system; thus physicians should be aware of the potential for increased interactions with other medications. Tolvaptan is a breakthrough in the therapy of hyponatremia as it directly combats elevated AVP levels associated with the syndrome of inappropriate secretion of antidiuretic hormone, congestive heart failure, and cirrhosis of the liver.Keywords: hyponatremia, arginine vasopressin, vasopressin receptors, syndrome of inappropriate antidiuretic hormone, congestive heart failure, liver cirrhosis

  19. The Real-Time Dose Measurement Scintillating Fiber Array for Brachytherapy Procedures (United States)

    Tynes, Lawrence


    Brachytherapy is a treatment modality that uses tiny radioactive sources (few mm in length) by delivering enough doses to kill cancer tumors or plaque build-up. The type of sources used in hospitals include both gamma and beta emitters. Presently, the technique suffers from not having a single detector with the capability of providing accurate dose distribution information within sub-mm accuracy. The current standard is based primarily on well chambers and film dosimetry. The Center for Advanced Medical Instrumentation (CAMI) at Hampton University is developing a Scintillating Fiber Based Beta Detector prototype in collaboration with the National Institute for Standards and Technology (NIST) to address this problem. The device is composed of an array of 1x1 mm^2 scintillating fibers optically coupled to photo-multiplier tubes for photon-to-current conversion. A CAMAC LabView based data acquisition system is used for real time data collection and histogramming, data analysis. A set of data were collected at the nearby Bon Secours DePaul Medical Center using a GammaMed 12i HDR after-loader housing a 6.62 mCi Ir-192 source. Preliminary comparison between our device and film dosimetry will be discussed.

  20. Postextrasystolic potentiation and contractile reserve: requirements and restrictions. (United States)

    Lust, R M; Lutherer, L O; Gardner, M E; Cooper, M W


    These studies were conducted to examine the basic characteristics of postextrasystolic potentiation (PESP) and the relationship of loading effects to PESP. Measurements of left ventricular (LV) and aortic pressures, the rate of pressure rise, and echocardiographically determined LV dimensions were made in anesthetized open-chest dogs. The hearts were paced, and timed extrasystoles were introduced that were followed by postextrasystoles (PES). PES's were elicited after an interval equal to either a full compensatory pause or a time when the diastolic properties of the LV could not be distinguished from control (isolength). Potentiation of contraction for the PES's introduced after an isolength pause was dependent on both the heart rate and the extrasystolic interval, whereas the PES's that occurred after a full pause showed no dependence on either of these intervals. PESP elicited during the isolength period was not dependent on either preload and afterload. It is concluded that PESP depends on the combination of heart rate and extrasystolic and postextrasystolic intervals. Further, PESP may be inaccurate in assessing contractile reserve unless the heart rate and extrasystolic interval are known and the PES is introduced after an isolength pause.

  1. Hemodynamic changes in depressive patients

    Institute of Scientific and Technical Information of China (English)

    MA Ying; LI Hui-chun; ZHENG Lei-lei; YU Hua-liang


    Objective: This study is aimed at exploring the relationship between hemodynamic changes and depressive and anxious symptom in depression patients. Methods: The cardiac function indices including the left stroke index (LSI), ejection fraction (EF), heart rate (HR), diastolic pressure mean (DPM), systolic pressure mean (SPM), left ventricle end-diastolic volume (LVDV), effective circulating volume (ECV), resistance total mean (RTM) and blood flow smooth degree (BFSD) were determined in 65 patients with major depressive disorders and 31 healthy normal controls. The clinical symptoms were assessed with Hamilton depression scale (HAMD) and Hamilton anxiety scale (HAMA). Results: In patients with depression without anxiety,LSI, EF, LVDV, DPM, SPM, ECV, BFSD were significantly lower than those in controls, while RTM was higher than that in controls. Patients with comorbidity of depression and anxiety showed decreased LVDV, ECV, BFSD, and increased HR in comparison with the controls. The anxiety/somatization factor score positively correlated with LSI, EF, LVDV, but negatively correlated with RTM. There was negative correlation between retardation factor score and DPM, SPM, LVDV. Conclusion: The study indicated that there are noticeable changes in left ventricle preload and afterload, blood pressure, peripheral resistance, and microcirculation in depressive patients, and that the accompanying anxiety makes the changes more complicated.

  2. Right Ventricular Adaptation Is Associated with the Glu298Asp Variant of the NOS3 Gene in Elite Athletes.

    Directory of Open Access Journals (Sweden)

    Zsolt Szelid

    Full Text Available Nitric oxide (NO, an important endogenous pulmonary vasodilator is synthetized by the endothelial NO synthase (NOS3. Reduced NO bioavailability and thus the Glu298Asp polymorphism of NOS3 may enhance right ventricular (RV afterload and hypertrophic remodeling and influence athletic performance. To test this hypothesis world class level athletes (water polo players, kayakers, canoeists, rowers, swimmers, n = 126 with a VO2 maximum greater than 50ml/kg/min were compared with non-athletic volunteers (n = 155. Cardiopulmonary exercise tests and cardiac magnetic resonance imaging (cMRI were performed to determine structural or functional changes. Genotype distribution of the NOS3 Glu298Asp polymorphism was not affected by gender or physical performance. Cardiac MRI showed increased stroke volume with eccentric hypertrophy in all athletes regardless of their genotype. However, the Asp allelic variant carriers had increased RV mass index (32±6g versus 27±6g, p<0.01 and larger RV stroke volume index (71±10ml versus 64±10ml, p<0.01 than athletes with a Glu/Glu genotype. Genotype was not significantly associated with athletic performance. In the non-athletic group no genotype related differences were detected. The association between the NOS3 Glu298Asp polymorphism and RV structure and dimension in elite athletes emphasizes the importance of NOS3 gene function and NO bioavailability in sport related cardiac adaptation.

  3. Monte Carlo model for a prototype CT-compatible, anatomically adaptive, shielded intracavitary brachytherapy applicator for the treatment of cervical cancer

    Energy Technology Data Exchange (ETDEWEB)

    Price, Michael J.; Gifford, Kent A.; Horton, John L. Jr.; Eifel, Patricia J.; Gillin, Michael T.; Lawyer, Ann A.; Mourtada, Firas [Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Division of Radiation Oncology, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 (United States); Department of Radiation Physics, University of Texas M. D. Anderson Cancer Center, 1220 Holcombe Boulevard, Houston, Texas 77030 and Graduate School of Biomedical Sciences, University of Texas-Houston, 6767 Bertner Avenue, Houston, Texas 77030 (United States)


    Purpose: Current, clinically applicable intracavitary brachytherapy applicators that utilize shielded ovoids contain a pair of tungsten-alloy shields which serve to reduce dose delivered to the rectum and bladder during source afterloading. After applicator insertion, these fixed shields are not necessarily positioned to provide optimal shielding of these critical structures due to variations in patient anatomies. The authors present a dosimetric evaluation of a novel prototype intracavitary brachytherapy ovoid [anatomically adaptive applicator (A{sup 3})], featuring a single shield whose position can be adjusted with two degrees of freedom: Rotation about and translation along the long axis of the ovoid. Methods: The dosimetry of the device for a HDR {sup 192}Ir was characterized using radiochromic film measurements for various shield orientations. A MCNPX Monte Carlo model was developed of the prototype ovoid and integrated with a previously validated model of a v2 mHDR {sup 192}Ir source (Nucletron Co.). The model was validated for three distinct shield orientations using film measurements. Results: For the most complex case, 91% of the absolute simulated and measured dose points agreed within 2% or 2 mm and 96% agreed within 10% or 2 mm. Conclusions: Validation of the Monte Carlo model facilitates future investigations into any dosimetric advantages the use of the A{sup 3} may have over the current state of art with respect to optimization and customization of dose delivery as a function of patient anatomical geometries.

  4. Evaluation of radioactive facilities safety using event trees; Evaluacion de la seguridad de instalaciones radiactivas utilizando arboles de evento

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez Saiz, A.; Cornejo Diaz, N.; Callis Fernandez, E.


    The validity of using the Event Trees as an adequate quantitative analysis model for doing radiological safety assessments of radioactive facilities is presented in this work. The radiological safety assessments made for four Departments of Radiotherapy (Teletherapy with Co-60 and High Dose Rate afterloading brachytherapy with Ir-192) from different hospitals were taken as the base for the analysis. By the use of this model were obtained quantitative results. The probabilities to reach a typical scenario in a first stage, and then, based on previously doses calculations in the same scenario, the total risk values, were obtained. The unauthorized entry into a radiation room while the source is in its fully exposed position was the main scenario identified. The numerical values obtained using this model supported the radiological safety assessments made during the licensing process of those installations. The analysis of the intrinsic safety systems of the radiotherapy equipments was not included in the study because it's design was accepted by the Regulatory Authority and also meet the criterion of proven effectiveness. The use of this model let us suggest modifications such as the adding of any component to the system and/or the change of its position in order to minimize the probability of reaching the mentioned scenario. The model is also useful to confirm that the present international requirements for the safety systems in this type of facilities lead to practices with better or similar total risk levels than others considered as safe. (Author)

  5. Measurement uncertainty in pulmonary vascular input impedance and characteristic impedance estimated from pulsed-wave Doppler ultrasound and pressure: clinical studies on 57 pediatric patients. (United States)

    Tian, Lian; Hunter, Kendall S; Kirby, K Scott; Ivy, D Dunbar; Shandas, Robin


    Pulmonary vascular input impedance better characterizes right ventricular (RV) afterload and disease outcomes in pulmonary hypertension compared to the standard clinical diagnostic, pulmonary vascular resistance (PVR). Early efforts to measure impedance were not routine, involving open-chest measurement. Recently, the use of pulsed-wave (PW) Doppler-measured velocity to non-invasively estimate instantaneous flow has made impedance measurement more practical. One critical concern remains with clinical use: the measurement uncertainty, especially since previous studies only incorporated random error. This study utilized data from a large pediatric patient population to comprehensively examine the systematic and random error contributions to the total impedance uncertainty and determined the least error prone methodology to compute impedance from among four different methods. We found that the systematic error contributes greatly to the total uncertainty and that one of the four methods had significantly smaller propagated uncertainty; however, even when this best method is used, the uncertainty can be large for input impedance at high harmonics and for the characteristic impedance modulus. Finally, we found that uncertainty in impedance between normotensive and hypertensive patient groups displays no significant difference. It is concluded that clinical impedance measurement would be most improved by advancements in instrumentation, and the best computation method is proposed for future clinical use of the input impedance.

  6. Stem signal suppression in fiber-coupled Al2O3:C dosimetry for 192Ir brachytherapy

    DEFF Research Database (Denmark)

    Kertzscher Schwencke, Gustavo Adolfo Vladimir; Andersen, Claus Erik; Edmund, J.M.


    was adapted for on-line in-vivo dosimetry using fiber-coupled carbon doped aluminum oxide (Al2O3:C). The technique involved a two-channel optical filtration of the radioluminescence (RL) emitted from a pre-irradiated Al2O3:C crystal with enhanced sensitivity. The system responded linearly in the absorbed dose......The stem signal, composed of fluorescence and Čerenkov light, becomes a significant source of uncertainty in fiber-coupled afterloaded brachytherapy dosimetry when the source dwells near the fiber cable but far from the detector. A stem suppression technique originally developed for scintillators...... range 0.05–50 Gy, as needed under high dose rate (HDR) conditions. The dosimeter was irradiated in a water phantom using a 37 GBq 192Ir source at source-to-crystal distances ranging from 0.5 cm to 6.7 cm. For irradiation conditions that generated a stem component in the range 4%–15% in the unfiltered...

  7. Fiber-coupled radioluminescence dosimetry with saturated Al2O3:C crystals: Characterization in 6 and 18 MV photon beams

    DEFF Research Database (Denmark)

    Andersen, Claus Erik; Damkjær, Sidsel Marie Skov; Kertzscher Schwencke, Gustavo Adolfo Vladimir


    Radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon-doped aluminum oxide crystals can be used for medical dosimetry in external beam radiotherapy and remotely afterloaded brachytherapy. The RL/OSL signals are guided from the treatment room to the readout instrumentation...... using optical fiber cables, and in vivo dosimetry can be carried out in real time while the dosimeter probes are in the patient. The present study proposes a new improved readout protocol based solely on the RL signal from Al2O3:C. The key elements in the protocol are that Al2O3:C is pre-dosed with 20...... ((−0.21 ± 0.01)%/ °C), and dose-delivery rate ((−0.22 ± 0.01)% per 100 MU/min). A temporal gating technique was used for separation of RL and stem signals (i.e. Cerenkov light and fluorescence induced in the optical fiber cable during irradiation). The new readout protocol was a substantial improvement...

  8. [Vasodilator therapy in pulmonary hypertension and chronic obstructive lung disease (COPD). Hemodynamic studies exemplified by nifedipine and nitroglycerin]. (United States)

    Gassner, A; Fridrich, L; Magometschnigg, D; Sommer, G; Klicpera, M


    In 41 patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension, the effects of sublingual administration of 20 mg nifedipine and 0.8 mg nitroglycerin on the hemodynamics were assessed at rest and during bicycle ergometry. Additionally, in six patients, the effects of nifedipine during longterm treatment were analyzed. On acute testing, at rest and during exercise nifedipine led to decreases in mean pulmonary artery pressure of 16% and 23% and pulmonary arteriolar resistance of 23 and 35%, respectively, in 81% (17/21) of the patients. The reduction in the pulmonary vascular resistance was greater than that of the systemic resistance. In all patients, cardiac output increased. There was a similar number of responders to nitroglycerin (16/20). The reductions in mean pulmonary artery pressure and pulmonary arteriolar resistance ranging between 20 and 25% at rest and during exercise were comparable to those affected by nifedipine. In addition to the right ventricular afterload reduction, there was a decrease in cardiac output of 17%. During longterm treatment with nifedipine (average 18 months), the reduction in mean pulmonary artery pressure and pulmonary arteriolar resistance was not of the same magnitude as seen on acute testing. This may be due primarily to progression of the underlying disease since pulmonary function studies demonstrated an increase in the obstructive component. With the intention of circumventing or postponing the onset of right ventricular failure, the individual patient should undergo hemodynamic studies to delineate the optimal medication.

  9. Critical care for paediatric patients with heart failure. (United States)

    Costello, John M; Mazwi, Mjaye L; McBride, Mary E; Gambetta, Katherine E; Eltayeb, Osama; Epting, Conrad L


    This review offers a critical-care perspective on the pathophysiology, monitoring, and management of acute heart failure syndromes in children. An in-depth understanding of the cardiovascular physiological disturbances in this population of patients is essential to correctly interpret clinical signs, symptoms and monitoring data, and to implement appropriate therapies. In this regard, the myocardial force-velocity relationship, the Frank-Starling mechanism, and pressure-volume loops are discussed. A variety of monitoring modalities are used to provide insight into the haemodynamic state, clinical trajectory, and response to treatment. Critical-care treatment of acute heart failure is based on the fundamental principles of optimising the delivery of oxygen and minimising metabolic demands. The former may be achieved by optimising systemic arterial oxygen content and the variables that determine cardiac output: heart rate and rhythm, preload, afterload, and contractility. Metabolic demands may be decreased by a number of ways including positive pressure ventilation, temperature control, and sedation. Mechanical circulatory support should be considered for refractory cases. In the near future, monitoring modalities may be improved by the capture and analysis of complex clinical data such as pressure waveforms and heart rate variability. Using predictive modelling and streaming analytics, these data may then be used to develop automated, real-time clinical decision support tools. Given the barriers to conducting multi-centre trials in this population of patients, the thoughtful analysis of data from multi-centre clinical registries and administrative databases will also likely have an impact on clinical practice.

  10. A novel paradigm for heart failure with preserved ejection fraction: comorbidities drive myocardial dysfunction and remodeling through coronary microvascular endothelial inflammation. (United States)

    Paulus, Walter J; Tschöpe, Carsten


    Over the past decade, myocardial structure, cardiomyocyte function, and intramyocardial signaling were shown to be specifically altered in heart failure with preserved ejection fraction (HFPEF). A new paradigm for HFPEF development is therefore proposed, which identifies a systemic proinflammatory state induced by comorbidities as the cause of myocardial structural and functional alterations. The new paradigm presumes the following sequence of events in HFPEF: 1) a high prevalence of comorbidities such as overweight/obesity, diabetes mellitus, chronic obstructive pulmonary disease, and salt-sensitive hypertension induce a systemic proinflammatory state; 2) a systemic proinflammatory state causes coronary microvascular endothelial inflammation; 3) coronary microvascular endothelial inflammation reduces nitric oxide bioavailability, cyclic guanosine monophosphate content, and protein kinase G (PKG) activity in adjacent cardiomyocytes; 4) low PKG activity favors hypertrophy development and increases resting tension because of hypophosphorylation of titin; and 5) both stiff cardiomyocytes and interstitial fibrosis contribute to high diastolic left ventricular (LV) stiffness and heart failure development. The new HFPEF paradigm shifts emphasis from LV afterload excess to coronary microvascular inflammation. This shift is supported by a favorable Laplace relationship in concentric LV hypertrophy and by all cardiac chambers showing similar remodeling and dysfunction. Myocardial remodeling in HFPEF differs from heart failure with reduced ejection fraction, in which remodeling is driven by loss of cardiomyocytes. The new HFPEF paradigm proposes comorbidities, plasma markers of inflammation, or vascular hyperemic responses to be included in diagnostic algorithms and aims at restoring myocardial PKG activity.

  11. Prospective multi-center trial utilizing electronic brachytherapy for the treatment of endometrial cancer

    Directory of Open Access Journals (Sweden)

    Thropay John P


    Full Text Available Abstract Background A modified form of high dose rate (HDR brachytherapy has been developed called Axxent Electronic Brachytherapy (EBT. EBT uses a kilovolt X-ray source and does not require treatment in a shielded vault or a HDR afterloader unit. A multi-center clinical study was carried out to evaluate the success of treatment delivery, safety and toxicity of EBT in patients with endometrial cancer. Methods A total of 15 patients with stage I or II endometrial cancer were enrolled at 5 sites. Patients were treated with vaginal EBT alone or in combination with external beam radiation. Results The prescribed doses of EBT were successfully delivered in all 15 patients. From the first fraction through 3 months follow-up, there were 4 CTC Grade 1 adverse events and 2 CTC Grade II adverse events reported that were EBT related. The mild events reported were dysuria, vaginal dryness, mucosal atrophy, and rectal bleeding. The moderate treatment related adverse events included dysuria, and vaginal pain. No Grade III or IV adverse events were reported. The EBT system performed well and was associated with limited acute toxicities. Conclusions EBT shows acute results similar to HDR brachytherapy. Additional research is needed to further assess the clinical efficacy and safety of EBT in the treatment of endometrial cancer.

  12. Pulsatile flow and simple flow control method during weaning period in centrifugal pump: toward more expanded usage in open heart surgery. (United States)

    Nishida, H; Koyanagi, H; Endo, M; Suzuki, S; Oshiyama, H; Nojiri, C; Fukasawa, H; Akutsu, T


    To expand the usage of the centrifugal pump (CP) in open heart surgery, we performed two studies. In the first, we evaluated pulsatile flow in the CP. In vitro pump performance of the Terumo Capiox pump (TCP) and the Sarns Delphin pump (SDP) and increase of free hemoglobin (mg/dl) after driving 6 h were investigated using bovine blood. A roller pump (RP) was used as a comparison. Equally effective pulsatile flow was obtained in both CPs. Hemolysis was less severe in TCP (120 mg/dl) than SDP (210 mg/dl) and RP (320 mg/dl). In the second study, we evaluated a simple flow control method. Flow rate was easily controlled with step-wise clamping of 3-pronged tubing (Triple-flow) without changing rotational speed, regardless of afterload. Fluctuation of flow was much less with this method than with the rotational speed change method. The use of pulsatile flow of TCP, with its minimum increase of hemolysis and the easier flow control method during the weaning process, may expand the usage of CP in open heart surgery.

  13. Tolerance of the carotid-sheath contents to brachytherapy: an experimental study

    Energy Technology Data Exchange (ETDEWEB)

    Werber, J.L.; Sood, B.; Alfieri, A.; McCormick, S.A.; Vikram, B. (Department of Otolaryngology--Head and Neck Surgery, New York Medical College, Beth Israel (USA))


    Tumor invasion of the carotid artery is a potential indication for brachytherapy, which delivers a high dose of irradiation to residual tumor while limiting the dose to adjacent healthy tissues. The tolerance of carotid-sheath contents to varying doses of brachytherapy, however, has not been clearly established. In order to evaluate brachytherapy effects on carotid-sheath contents, after-loading catheters were implanted bilaterally in 3 groups of 6 rabbits each (18 rabbits). Iridium 192 brachytherapy doses of either 5000 cGy (rad), 9000 cGy, or 13,000 cGy were delivered unilaterally, with the contralateral neck serving as a nonirradiated control in each animal. There were no carotid ruptures and wound healing was normal. Two animals from each group were killed at 6, 20, and 48 weeks. Even at the highest dose (13,000 cGy), nerve conduction studies performed on the vagus nerve prior to sacrifice revealed no increased latency, histologic changes were minimal, and carotid arteries were patent. These observations suggest that the carotid-sheath contents in healthy rabbits could tolerate high doses (up to 13,000 cGy) of low-dose-rate interstitial brachytherapy without complications.

  14. [Risk factors of late complications after interstitial 192Ir brachytherapy in cancers of the oral cavity]. (United States)

    Peiffert, D


    Brachytherapy has confirmed its prevailing role in conservative treatment of oral cavity carcinomas. To describe late toxicity in long-term surviving patients, comparisons with other series are necessary. Study of series of patients implanted for floor of the mouth or mobile tongue shows the need for more detailed data. Dental prophylaxy and lead protection of the mandibule, good indications and techniques of brachytherapy are necessary to avoid late complications. Some treatment factors have proved to be of good prognosis for late complications through multivariate analysis of large series treated with lr 192 wires, using the Paris system, eg, dose rate lower than 0.5 or 0.7 Gy/h, intersource spacing smaller than 1.2 or 1.5 cm, treated surface less than 12 cm2, lineic activity less than 1.5 mCi/cm, less than 1 cm diameter hyperdose, and use of mandibular lead protections. Tumor volume and location to the floor of mouth lead to higher risk of complications. Knowledge of treatment-related factors is important, with the development of new afterloading projectors allowing to control the dose rate and correct small inhomogeneities. High-dose rate exclusive brachytherapy is not recommended. More precise and reproducible classification should be used to report complications in series leading to publications in the future, thus allowing to compare results, reduce complication rates and improve the quality of life.

  15. Cardiac performance correlates of relative heart ventricle mass in amphibians. (United States)

    Kluthe, Gregory J; Hillman, Stanley S


    This study used an in situ heart preparation to analyze the power output and stroke work of spontaneously beating hearts of four anurans (Rhinella marina, Lithobates catesbeianus, Xenopus laevis, Pyxicephalus edulis) and three urodeles (Necturus maculosus, Ambystoma tigrinum, Amphiuma tridactylum) that span a representative range of relative ventricle mass (RVM) found in amphibians. Previous research has documented that RVM correlates with dehydration tolerance and maximal aerobic capacity in amphibians. The power output (mW g(-1) ventricle mass) and stroke work (mJ g(-1) ventricle muscle mass) were independent of RVM and were indistinguishable from previously published results for fish and reptiles. RVM was significantly correlated with maximum power output (P max, mW kg(-1) body mass), stroke volume, cardiac output, afterload pressure (P O) at P max, and preload pressure (P I) at P max. P I at P max and P O at P max also correlated very closely with each other. The increases in both P I and P O at maximal power outputs in large hearts suggest that concomitant increases in blood volume and/or increased modulation of vascular compliance either anatomically or via sympathetic tone on the venous vasculature would be necessary to achieve P max in vivo. Hypotheses for variation in RVM and its concomitant increased P max in amphibians are developed.

  16. One piece ultracompact totally implantable electromechanical total artificial heart for permanent use. (United States)

    Takatani, Setsuo; Sakamoto, Tohru; Ohuchi, Katsuhiro; Nakamura, Makoto; Mizuno, Tomohiro; Arai, Hirokuni


    An ultracompact, one piece, totally implantable electromechanical total artificial heart (TAH) has been developed as a permanent replacement for failing hearts. It consists of left and right pusher plate blood pumps (stroke volume 55 ml) made of titanium alloy (Ti-6Al-7Nb) sandwiching a miniaturized electromechanical actuator between them. The diameter of the TAH is 90 mm, with a thickness of 70 mm, yielding an overall volume of 400 ml. It weighs 450 g. Although it is miniaturized, it provided a maximum pump output of 8 L/min against a left afterload of 100 mm Hg. It required approximately 12 watts to provide a pump output of 6.5 L/min with maximum efficiency of 13.5%. To balance left and right flow, the right stroke length was made 10% shorter than the left, and an auxiliary compliance chamber was used to compensate for additional flow differences between them. Motor commutation pulses and a Hall effect pusher plate sensor signal were used in the controller to implement the left master alternate variable rate mode. The calf fitting study revealed excellent anatomic compatibility, and the first successful survivor was obtained in December 2001. Studies of system endurance and biocompatibility are required to ensure long-term reliability. This TAH is promising for permanent replacement of the failing heart as well as for bridge to heart transplantation for the smaller size group of end-stage cardiac patients.

  17. Rationale and Description of Right Ventricle-Protective Ventilation in ARDS. (United States)

    Paternot, Alexis; Repessé, Xavier; Vieillard-Baron, Antoine


    Pulmonary vascular dysfunction is associated with ARDS and leads to increased right-ventricular afterload and eventually right-ventricular failure, also called acute cor pulmonale. Interest in acute cor pulmonale and its negative impact on outcome in patients with ARDS has grown in recent years. Right-ventricular function in these patients should be closely monitored, and this is helped by the widespread use of echocardiography in intensive care units. Because mechanical ventilation may worsen right-ventricular failure, the interaction between the lungs and the right ventricle appears to be a key factor in the ventilation strategy. In this review, a rationale for a right ventricle-protective ventilation approach is provided, and such a strategy is described, including the reduction of lung stress (ie, the limitation of plateau pressure and driving pressure), the reduction of PaCO2 , and the improvement of oxygenation. Prone positioning seems to be a crucial part of this strategy by protecting both the lungs and the right ventricle, resulting in increased survival of patients with ARDS. Further studies are required to validate the positive impact on prognosis of right ventricle-protective mechanical ventilation.

  18. Current Perspectives on Systemic Hypertension in Heart Failure with Preserved Ejection Fraction. (United States)

    Tam, Marty C; Lee, Ran; Cascino, Thomas M; Konerman, Matthew C; Hummel, Scott L


    Heart failure with preserved ejection fraction (HFpEF) is a prevalent but incompletely understood syndrome. Traditional models of HFpEF pathophysiology revolve around systemic HTN and other causes of increased left ventricular afterload leading to left ventricular hypertrophy (LVH) and diastolic dysfunction. However, emerging models attribute the development of HFpEF to systemic proinflammatory changes secondary to common comorbidities which include HTN. Alterations in passive ventricular stiffness, ventricular-arterial coupling, peripheral microvascular function, systolic reserve, and chronotropic response occur. As a result, HFpEF is heterogeneous in nature, making it difficult to prescribe uniform therapies to all patients. Nonetheless, treating systemic HTN remains a cornerstone of HFpEF management. Antihypertensive therapies have been linked to LVH regression and improvement in diastolic dysfunction. However, to date, no therapies have definitive mortality benefit in HFpEF. Non-pharmacologic management for HTN, including dietary modification, exercise, and treating sleep disordered breathing, may provide some morbidity benefit in the HFpEF population. Future research is need to identify effective treatments, perhaps in more specific subgroups, and focus may need to shift from reducing mortality to improving exercise capacity and symptoms. Tailoring antihypertensive therapies to specific phenotypes of HFpEF may be an important component of this strategy.

  19. Captopril-induced reduction of regurgitation fraction in aortic insufficiency: Acute and long-term effects

    Energy Technology Data Exchange (ETDEWEB)

    Kropp, J.; Heck, I.; Reske, S.N.; Biersack, H.J.; Mattern, H.; Winkler, C.; Polikl, M.


    In aortic insufficiency (AI) the inhibition of the stimulated Renin-Angiotensin-System (RAS) by Captopril (C) reduced afterload and leads consequently to a diminished regurgitation fraction (RF). In 17 patients (pts) with pure severe AI RF, left ventricular ejection fraction (LVEFE) and heart rate were determined before (1) and 1 hr after (2) administration of 25 mg of C.Long term dosis was 3 x 25 mg of C and follow up time was 3-11 months (medium:6). The values were determined by gated radionuclide ventriculography using red blood cells labeled in vivo with 15 mCi Tc-99mROI's were selected over both ventricles in enddiastolic and endsystolic frames. Ventricular boundaries were defined by a fourier phase image overlay. RF was calculated by the background corrected count rate ratio of left and right ventricular ROI. Systolic and diastolic blood pressure (BPs,BPd), plasma levels of angiotensin I,II(A1,A2) and the activity of angiotensin converting enzyme (ACE) were determined before and 1 hr after C administration. After C there is a decrease in RF which persists in the long term follow period in up to to now 8 pts. The authors conclude: inhibition of ACE reduces significantly aortic regurgitation in patients with AI and has thus a beneficial effect on left ventricular performance. This effect persists in long term treatment and therefore seems beneficial to delay the point of operation.

  20. Pharmacology of Casimiroa edulis; II. Cardiovascular effects in the anesthesized dog. (United States)

    Vidrio, H; Magos, G A


    The cardiovascular effects of an aqueous extract of seeds of Casimiroa edulis were assessed in pentobarbital-anesthetized dogs. The extract produced marked hypotension which lasted more than two hours; it was accompanied by moderate and less persistent bradycardia. The histaminergic nature of these effects was investigated in animals pretreated with the specific antagonists diphenhydramine, cimetidine, or a combination of both agents. These experiments showed that both H1- and H2-receptors were involved in the hypotensive response, while the bradycardia was mediated solely through an H1-mechanism. In open-chest dogs instrumented for recording cardiac output (ascending aortic flow), left ventricular contractility (dp/dt), central venous pressure (superior vena cava), systemic blood pressure, heart rate, total peripheral resistance and stroke volume, the extract decreased blood pressure and peripheral resistance and increased cardiac output and stroke volume, without modifying the other parameters. It was concluded that the cardiovascular pattern of Casimiroa edulis in the dog is that of a peripheral arterial vasodilator and that it increases cardiac output by reducing left ventricular afterload.

  1. New-Onset Myocarditis in an Immunocompetent Adult with Acute Metapneumovirus Infection. (United States)

    Weinreich, Mark A; Jabbar, Ahmad Y; Malguria, Nagina; Haley, Robert W


    Introduction. A number of viruses have been implicated in viral myocarditis; however, there has been no previous report of human metapneumovirus (hMPV) causing this condition. Discovered in 2001, hMPV is typically associated with upper respiratory illness, mainly affecting children. Case Presentation. We report the case of a 25-year-old man with acute systolic heart failure from viral myocarditis secondary to the hMPV. The patient was initially admitted to the general medical ward but developed increasing oxygen requirements resulting in transfer to the cardiac intensive care unit. Cardiac magnetic resonance imaging was used to help confirm the diagnosis. He was treated with intravenous diuretics, and afterload and preload agents, and he was subsequently discharged home after seven days of hospitalization. Discussion. hMPV is typically a respiratory pathogen; however, it was associated with in myocarditis in our patient. Due to the recent ability to detect this virus, we may see more cases of this, particularly during peak months of infection. Conclusion. This is the first case description of myocarditis associated with hMPV infection.

  2. New-Onset Myocarditis in an Immunocompetent Adult with Acute Metapneumovirus Infection

    Directory of Open Access Journals (Sweden)

    Mark A. Weinreich


    Full Text Available Introduction. A number of viruses have been implicated in viral myocarditis; however, there has been no previous report of human metapneumovirus (hMPV causing this condition. Discovered in 2001, hMPV is typically associated with upper respiratory illness, mainly affecting children. Case Presentation. We report the case of a 25-year-old man with acute systolic heart failure from viral myocarditis secondary to the hMPV. The patient was initially admitted to the general medical ward but developed increasing oxygen requirements resulting in transfer to the cardiac intensive care unit. Cardiac magnetic resonance imaging was used to help confirm the diagnosis. He was treated with intravenous diuretics, and afterload and preload agents, and he was subsequently discharged home after seven days of hospitalization. Discussion. hMPV is typically a respiratory pathogen; however, it was associated with in myocarditis in our patient. Due to the recent ability to detect this virus, we may see more cases of this, particularly during peak months of infection. Conclusion. This is the first case description of myocarditis associated with hMPV infection.

  3. Clinical outcome of high-dose-rate interstitial brachytherapy in patients with oral cavity cancer

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sung Uk; Cho, Kwan Ho; Moon, Sung Ho; Choi, Sung Weon; Park, Joo Yong; Yun, Tak; Lee, Sang Hyun; Lim, Young Kyung; Jeong, Chi Young [National Cancer Center, Goyang (Korea, Republic of)


    To evaluate the clinical outcome of high-dose-rate (HDR) interstitial brachytherapy (IBT) in patients with oral cavity cancer. Sixteen patients with oral cavity cancer treated with HDR remote-control afterloading brachytherapy using 192Ir between 2001 and 2013 were analyzed retrospectively. Brachytherapy was administered in 11 patients as the primary treatment and in five patients as salvage treatment for recurrence after the initial surgery. In 12 patients, external beam radiotherapy (50-55 Gy/25 fractions) was combined with IBT of 21 Gy/7 fractions. In addition, IBT was administered as the sole treatment in three patients with a total dose of 50 Gy/10 fractions and as postoperative adjuvant treatment in one patient with a total of 35 Gy/7 fractions. The 5-year overall survival of the entire group was 70%. The actuarial local control rate after 3 years was 84%. All five recurrent cases after initial surgery were successfully salvaged using IBT +/- external beam radiotherapy. Two patients developed local recurrence at 3 and 5 months, respectively, after IBT. The acute complications were acceptable (< or =grade 2). Three patients developed major late complications, such as radio-osteonecrosis, in which one patient was treated by conservative therapy and two required surgical intervention. HDR IBT for oral cavity cancer was effective and acceptable in diverse clinical settings, such as in the cases of primary or salvage treatment.

  4. Nanotargeted Radionuclides for Cancer Nuclear Imaging and Internal Radiotherapy

    Directory of Open Access Journals (Sweden)

    Gann Ting


    Full Text Available Current progress in nanomedicine has exploited the possibility of designing tumor-targeted nanocarriers being able to deliver radionuclide payloads in a site or molecular selective manner to improve the efficacy and safety of cancer imaging and therapy. Radionuclides of auger electron-, α-, β-, and γ-radiation emitters have been surface-bioconjugated or after-loaded in nanoparticles to improve the efficacy and reduce the toxicity of cancer imaging and therapy in preclinical and clinical studies. This article provides a brief overview of current status of applications, advantages, problems, up-to-date research and development, and future prospects of nanotargeted radionuclides in cancer nuclear imaging and radiotherapy. Passive and active nanotargeting delivery of radionuclides with illustrating examples for tumor imaging and therapy are reviewed and summarized. Research on combing different modes of selective delivery of radionuclides through nanocarriers targeted delivery for tumor imaging and therapy offers the new possibility of large increases in cancer diagnostic efficacy and therapeutic index. However, further efforts and challenges in preclinical and clinical efficacy and toxicity studies are required to translate those advanced technologies to the clinical applications for cancer patients.

  5. Intelligent Li ion battery management based on a digital signal processor for a moving actuator total artificial heart. (United States)

    Kim, W E; Ahn, J M; Choi, S W; Min, B G


    An intelligent Li Ion battery management (ILBM) system was developed based on a digital signal processor (DSP). Instead of using relatively complicated hardware charging control, a DSP algorithm was used, and favorable characteristics in volume, mass, and temperature increase of the implantable battery were achieved. In vitro tests were performed to evaluate the DSP based algorithm for Li Ion charging control (24 V dc motor input power 16 W, 5 L/min, 100 mmHg afterload). In this article, the first improvement was volume reduction using a Li Ion battery (3.6 V/Cell, 900 mA, seven cells: 25.2 V, 22.7 W). Its volume and mass were decreased by 40% and 50% respectively (40*55*75 mm, 189 g), compared to previously reported results, with total energy capacity increased by 110% (more than 60 min vs 25 min run time in the other battery). The second improvement includes the ILBM, which can control the performance detection for each unit cell and has a low temperature rise. The ILBM's unit cell energy detection was important because the low performance of one cell dropped to 50% of the total performance along with a 20% increase in surface temperature. All electronics for a transcutaneous energy transmission (TET), battery, and telemetry were finalized for hybridization and used for total artificial heat (TAH) implantation.

  6. Anaesthesia management of a patient with hypertrophic obstructive cardiomyopathy undergoing Morrow′s septal myectomy

    Directory of Open Access Journals (Sweden)

    Naresh Kumar Agarwal


    Full Text Available Hypertrophic obstructive cardiomyopathy (HOCM is a rare disorder. There is paucity of literature on anaesthetic management of this disorder. Aim of this case report is to highlight the anaesthetic problems encountered during management of such patients. A thirty-five year old male was admitted with atypical chest pain for last one year. X-ray chest revealed cardiomegaly (CT ratio 0.6. Electrocardiographic findings were left axis deviation with left ventricular hypertrophy. On echocardiography, there was moderate mitral regurgitation (MR, systolic anterior motion (SAM of anterior mitral leaflet and prominent systolic narrowing of left ventricle cavity. Transoesophageal echocardiography (TOE also showed an anomalous muscle bundle stretching into LV causing obstruction. Preload was kept high. Systemic vascular resistance (SVR was maintained, avoiding use of vasodilators and inotropes. Morrow′s septal myectomy was done. Anomalous muscle bundle was excised. On postoperative TOE, there was no MR and no obstruction. Optimal anaesthetic management in such patients involves maintaining adequate preload, systemic vascular resistance and minimal outflow obstruction. Other considerations are to maintain haemodynamic stability, sinus rhythm and afterload. Transoesophageal echocardiography is an extremely useful monitoring device in such patients.

  7. Radionuclide venticulography in the evaluation of Captopril-mediated decrease of regurgitation in aortic and mitral insufficiency. Pt. 1. Methods and hormonal response

    Energy Technology Data Exchange (ETDEWEB)

    Kropp, J.; Schmidt, H.; Knopp, R.; Biersack, H.J. (Bonn Univ. (Germany). Dept. of Nuclear Medicine); Heck, I. (Lukas Hospital, Altenkirchen (Germany). Dept. of Internal Medicine); Nitsch, J. (St.-Agnes Hospital, Bocholt (Germany). Dept. of Internal Medicine)

    Nineteen patients with valve insufficency (VI) were investigated by gated-radionuclide-ventriculography (RNVG) to evaluate regurgitation fraction (RF). Ten of these patients were evaluated with right- and left heart catheterization (LRHC). 16 patients without valvular disease were investigated by left ventricular cineventriculography (LVCV) and RNVG. RNVG-left ventricular enddiastolic volume (LVEDV) was determined by a count-based method (LVED{sub cb}) as well as by a geometrical method (LVEDV{sub g}). After administration of Captopril (C), levels of angiotensin I increased in patients with VI (from 233 to 864 pg/ml, p<0.001) while angiotensin II decreased (from 43 to 30 pg/ml, p<0.001). Correlation of LRHC-RF and RNVG-RF, LVCV-LVEDV and LVEDV{sub cb}, LVCV-LVEDV and LVEDV{sub g} was characterized by the following equations: y=0.78x+6.9r=0.89; y=1.0x+5.7,r=0.93; and y=0.5x+92,r=0.45, respectively. Indexterms: Valve insufficency - radionuclide ventriculography - Captopril - Afterload reduction - regurgitation volume. (orig.).

  8. A fast building and effective hydraulic pediatric mock circulatory system for the evaluation of a left ventricular assist device. (United States)

    Huang, Feng; Ruan, Xiaodong; Zou, Jun; Qian, Wenwei; Fu, Xin


    A mock circulatory system (MCS) has been proven a useful tool in the development of a ventricular assist device. Nowadays a MCS aimed at the evaluation of pediatric blood pumps, which require many different considerations compared with that of adults, has become an urgent need. This article presents the details on how the dynamic process of the left ventricle, which is described in terms of the pressure-volume loop (P-V loop), and the properties of the circulation such as compliance and resistance are simulated by hydraulic elements. A simple control method is introduced to reproduce the physiological afterload and preload sensitivities of the mock ventricle for the first time. Hemodynamic performance of the system is obtained by medical sensors to validate the similarity of the device to the native cardiovascular system. The actual sensitivities of the mock ventricle are obtained intuitively from the changes of the P-V loops. The aortic input impedance of the MCS is also obtained and compared with the data from previous medical reports. At last a pediatric left ventricular assist device (LVAD) prototype is introduced for testing to further verify the effectiveness of the MCS. The experimental results indicate that this pediatric MCS is capable of reproducing basic hemodynamic characteristics of a child in both normal and pathological conditions and it is sufficient for testing a pediatric LVAD. Besides, most components constituting the main hydraulic part of this MCS are inexpensive off-the-shelf products, making the MCS easy and fast to build.

  9. Transcutaneous electrical nerve stimulation (TENS) in angina pectoris. (United States)

    Mannheimer, C; Carlsson, C A; Vedin, A; Wilhelmsson, C


    The aim of this study was to determine the efficacy of transcutaneous electrical nerve stimulation (TENS) in the treatment of chronic stable severe angina pectoris. In a short-term study the effect of TENS was studied in 10 male patients with angina pectoris (functional class III and IV). All patients had previously been stabilized on long-term maximal oral treatment. The effects of the treatment were measured by means of repeated bicycle ergometer tests. All patients had an increased working capacity (16-85%), decreased ST segment depression and reduced recovery time during TENS. No adverse effects were observed. A long-term study of TENS on similarly selected patients showed beneficial effects in terms of pain reduction, reduced frequency of anginal attacks, increased physical activity and increased working capacity during bicycle ergometer tests. An invasive study was carried out with respect to systemic and coronary hemodynamics and myocardial metabolism during pacing provoked myocardial ischemia in 13 patients. The results showed that TENS led to an increased tolerance to pacing, improved lactate metabolism, less pronounced ST segment depression. A drop in systolic blood pressure during TENS treatment at identical pacing rates indicated a decreased afterload. An increased coronary flow to ischemic areas in the myocardium was supported by the fact that the rate pressure product during anginal pain increased during TENS.

  10. Use of paravascular admittance waveforms to monitor relative change in arterial blood pressure (United States)

    Zielinski, Todd M.; Hettrick, Doug; Cho, Yong


    Non-invasive methods to monitor ambulatory blood pressure often have limitations that can affect measurement accuracy and patient adherence [1]. Minimally invasive measurement of a relative blood pressure surrogate with an implantable device may provide a useful chronic diagnostic and monitoring tool. We assessed a technique that uses electrocardiogram and paravascular admittance waveform morphology analysis to one, measure a time duration (vascular tone index, VTI in milliseconds) change from the electrocardiogram R-wave to admittance waveform peak and two, measure the admittance waveform minimum, maximum and magnitude as indicators of change in arterial compliance/distensibility or pulse pressure secondary to change in afterload. Methods: Five anesthetized domestic pigs (32 ± 4.2 kg) were used to study the effects of phenylephrine (1-5 ug/kg/min) on femoral artery pressure and admittance waveform morphology measured with a quadrapolar electrode array catheter placed next to the femoral artery to assess the relative change in arterial compliance due to change in peripheral vascular tone. Results: Statistical difference was observed (p blood pressure may be suitable for implantable devices to detect progression of cardiovascular disease such as hypertension.


    Directory of Open Access Journals (Sweden)



    Full Text Available BACKGROUND AND OBJECTIVES: In the last decade, anemia is recognized as an important cause of morbidity, a factor limiting physical activity, responsible for a poor quality of life, and a predictor of unfavorable outcomes. Anemia is emerging as a potential contributor to the development and progression of cardiovascular disease. Hence the present study was undertaken to correlate echocardiographic changes with anemic status. METHODOLOGY: Present study was conducted in Al-Ameen Medical College and Government district Hospital, Bijapur. 31 anemic patients (aged 18-40 yrs. with Hb ≤7 gm. % were selected. All anemic patients were subjected for hemoglobin estimation and M mode 2D Echocardiography. Echocardiographic parameters- IVSTd, LVIDd, LVPWd, IVSTs, LVIDs, LVPWS, EDV, ESV, SV, SI, CI, EF, FS were studied and correlated with hemoglobin levels. Statistical analysis was done by correlation analysis. RESULTS: LVPWd, IVSTs, IVStd, LVPWs did not correlate with hemoglobin levels. LVIDd, LVIDs, EDV, ESV, SV, SI, CI were negatively correlated with hemoglobin levels in anemic patients. No correlation observed for EF, FS. INTERPRETATION AND CONCLUSION: The findings of negative correlation of echo parameters with anemic status may be as a consequence of hyperdynamic circulatory state leading to vascular and cardiac changes. These changes are mainly due to increased preload, decreased afterload, changes in cardiac geometry. These factors increase systolic wall stress and over time lead to LV systolic dysfunction

  12. Effects of Interaction Between Ventricular Assist Device Assistance and Autoregulated Mock Circulation Including Frank-Starling Mechanism and Baroreflex. (United States)

    Jansen-Park, So-Hyun; Mahmood, Mohammad Nauzef; Müller, Indra; Turnhoff, Lisa Kathrin; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Sonntag, Simon Johannes


    A mock heart circulation loop (MHCL) is a hydraulic model simulating the human circulatory system. It allows in vitro investigations of the interaction between cardiac assist devices and the human circulatory system. In this study, a preload sensitive MHCL, the MHCLAUTO , was developed to investigate the interaction between the left ventricle and left ventricular assist devices (LVADs). The Frank-Starling mechanism was modeled by regulating the stroke volume (SV) based on the measured mean diastolic left atrial pressure (MLAPdiast ). The baroreflex autoregulation mechanism was implemented to maintain a constant mean aortic pressure (MAP) by varying ventricular contractility (Emax ), heart rate (HR), afterload/systemic vascular resistance (SVR) and unstressed venous volume (UVV). The DP3 blood pump (Medos Medizintechnik GmbH) was used to simulate the LVAD. Characteristic parameters were measured in pathological conditions both with and without LVAD to assess the hemodynamic effect of LVAD on the MHCLAUTO . The results obtained from the MHCLAUTO show a high correlation to literature data. The study demonstrates the possibility of using the MHCLAUTO as a research tool to better understand the physiological interactions between cardiac implants and human circulation.

  13. Role of the Frank-Starling mechanism during maximal semisupine exercise after oral atenolol. (United States)

    Andersen, K; Vik-Mo, H


    Reproducible left ventricular dimensions were found by M-mode echocardiography in eight healthy men in the semisupine position during two maximal bicycle exercise tests, performed with four hours interval. Left ventricular end-diastolic dimension did not increase during maximal exercise, while fractional shortening increased by a decrease in end-systolic dimension. Twelve men studied by the same procedure were given 100 mg atenolol orally just after the first test which conspicuously reduced their heart rate response to exercise. End-diastolic dimension increased significantly from rest to peak exercise after the administration of atenolol in contrast to that before beta blockade, and fractional shortening at maximal exercise increased compared with the preceding control test. We conclude that atenolol changes the left ventricular response to maximal semisupine exercise in normal man, with dilatation and a concomitant increase in systolic myocardial shortening. This suggests that atenolol during maximal exercise reveals the part played by the Frank-Starling mechanism in cardiac reserve. In addition to that mechanism, the increased ventricular emptying is probably also the result of reduced afterload after administration of atenolol.

  14. 肥厚型梗阻性心肌病患者行髋关节置换术的麻醉处理%Anesthetic management of a patient with hypertrophic obstructive cardiomyopathy for hip joint replacement Introduction

    Institute of Scientific and Technical Information of China (English)

    刘秀芬; 王东信


    IntroductionHypertrophic cardiomyopathy(HCM)is not an uncommon cardiac disease now,it was reported that the prevalence of HCM is 0.18%in Chinese at present[ 1].Hypertrophic obstructive carchomyopathy(HOCM)is a subset of HCM with left ventricular outilow tract(LVOT)obstruction.Majority of case repofls have focused on anesthetic management of HOCM in children and parturients,eithercombined spinal and epidural(CSE)or general anesthesia selected.%@@ Hypertrophic cardiomyopathy (HCM) is not an uncommon cardiac disease now,it was reported that the prevalence of HCM is 0.18% in Chinese at present .Hypertrophic obstructive cardiomyopathy ( HOCM) is a subset of HCM with left ventricular outflow tract ( LVOT) obstruction.Majority of case reports have focused on anesthetic management of HOCM in children and parturients, either combined spinal and epidural (CSE) or general anesthesia selected.But there were existing debates about anesthetic methods used, some authors regarded spinal or epidural anesthesia as contraindicated for the sake of lowering afterload, some authors believed that the serious problems could occur during general anesthesia.

  15. Comparison of novel physiological load-adaptive control strategies for ventricular assist devices. (United States)

    Habigt, Moriz; Ketelhut, Maike; Gesenhues, Jonas; Schrödel, Frank; Hein, Marc; Mechelinck, Mare; Schmitz-Rode, Thomas; Abel, Dirk; Rossaint, Rolf


    Terminal heart failure (HF) is the most prevalent cause of death in the Western world and the implantation of a left ventricular assist device (LVAD) has become the gold standard therapy today. Most of the actually implanted devices are driven at a constant speed (CS) regardless of the patient's physiological demand. A new physiological controller [power ratio (PR) controller], which keeps a constant ratio between LVAD power and left ventricular power, a previous concept [preload responsive speed (PRS) controller], which adds a variable LVAD power to reach a defined stroke work, and a CS controller were compared with an unimpaired ventricle in a full heart computer simulation model. The effects of changes in preload, afterload and left ventricular contractility are displayed by global hemodynamics and ventricular pressure-volume loops. Both physiological controllers demonstrated the desired load dependency, whereas the PR controller exceeded the PRS controller in response to an increased load and contractility. Response was inferior when preload or contractility was decreased. Thus, the PR controller might lead to an increased exercise tolerance of the patient. Additional studies are required to evaluate the controllers in vivo.

  16. NADH fluorescence imaging of isolated biventricular working rabbit hearts. (United States)

    Asfour, Huda; Wengrowski, Anastasia M; Jaimes, Rafael; Swift, Luther M; Kay, Matthew W


    Since its inception by Langendorff(1), the isolated perfused heart remains a prominent tool for studying cardiac physiology(2). However, it is not well-suited for studies of cardiac metabolism, which require the heart to perform work within the context of physiologic preload and afterload pressures. Neely introduced modifications to the Langendorff technique to establish appropriate left ventricular (LV) preload and afterload pressures(3). The model is known as the isolated LV working heart model and has been used extensively to study LV performance and metabolism(4-6). This model, however, does not provide a properly loaded right ventricle (RV). Demmy et al. first reported a biventricular model as a modification of the LV working heart model(7, 8). They found that stroke volume, cardiac output, and pressure development improved in hearts converted from working LV mode to biventricular working mode(8). A properly loaded RV also diminishes abnormal pressure gradients across the septum to improve septal function. Biventricular working hearts have been shown to maintain aortic output, pulmonary flow, mean aortic pressure, heart rate, and myocardial ATP levels for up to 3 hours(8). When studying the metabolic effects of myocardial injury, such as ischemia, it is often necessary to identify the location of the affected tissue. This can be done by imaging the fluorescence of NADH (the reduced form of nicotinamide adenine dinucleotide)(9-11), a coenzyme found in large quantities in the mitochondria. NADH fluorescence (fNADH) displays a near linearly inverse relationship with local oxygen concentration(12) and provides a measure of mitochondrial redox state(13). fNADH imaging during hypoxic and ischemic conditions has been used as a dye-free method to identify hypoxic regions(14, 15) and to monitor the progression of hypoxic conditions over time(10). The objective of the method is to monitor the mitochondrial redox state of biventricular working hearts during protocols

  17. 长时间滚压泵辅助循环管理体会%The management experience of long duration roller pump ventricular assist device

    Institute of Scientific and Technical Information of China (English)

    王中; 王试福; 王大勇


    目的 总结本院51例心脏术后心脏和/或肺功能不全滚压泵长时间辅助循环(VAD)管理经验.方法 51例心脏术后患者因心脏和/或肺功能不全而难以脱离体外循环,采用滚压泵进行长时间心肺功能辅助,根据患者心肺功能状态分别采用全心辅助和单纯左心辅助两种辅助方式,辅助期间尽可能提供满意的灌注流量,重视各种脏器保护,注意维持内环境稳定,妥善调节前后负荷之间的关系.结果 全心辅助43例(其中单纯呼吸功能不全13例,全心功能不全27例,呼吸功能不全合并左心功能不全3例),单纯左心辅助8例.VAD时间360~1020(679±29)min,辅助后脱机或在IABP辅助下脱机并存活至出ICU 23例,辅助后不能脱机17例,辅助后脱机或在IABP辅助下脱机但术后10 d内死于ICU 11例.结论 心脏术后因心肺功能不全而难以脱离体外循环时应积极对衰竭器官进行辅助.选择适当辅助方式,精心进行流量调控,妥善进行前、后负荷管理,维持稳定内环境状态,可提高辅助成功率.%OBJECTIVE To summarize the management experience of long duration roller pump ventricular assist device ( VAD ) for left heart assistance in 51 post cardiac surgery patients with heart and/or lung dysfunction. METHODS Ventricular assist devices of roller pump were used for 51 patients who couldn't wean off ECC because of heart and/or lung dysfunction. According to patients' heart and lung condition, biventricular assist advice and left ventricular assist device were used respectively. During assistance,satisfactoryperfusion blood flow was provided and much attention was paid to the conservation of major organs. Body internal environment was maintained in normal status. The relationship between preload and afterload of the heart was adjusted adequately. RESULTS Biventricular assist device was used in 43 cases ( pure respiratory insufficiency 13 cases, biventricular dysfuntion 27 cases, respiratory

  18. Interstitial brachytherapy in carcinoma of the penis

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhary, A.J.; Ghosh, S.; Bhalavat, R.L. [Tata Memorial Hospital, Mumbai (India). Dept. of Radiation Oncology; Kulkarni, J.N. [Tata Memorial Hospital, Mumbai (India). Dept. of Surgery; Sequeira, B.V.E. [Tata Memorial Hospital, Mumbai (India). Dept. of Medical Physics


    Aim: Keeping in line with the increasing emphasis on organ preservation, we at the Tata Memorial Hospital have evaluated the role of Ir-192 interstitial implant as regards local control, functional and cosmetic outcome in early as well as locally recurrent carcinoma of the distal penis. Patients and Methods: From October 1988 to December 1996, 23 patients with histopathologically proven cancer of the penis were treated with radical radiation therapy using Ir-192 temporary interstitial implant. Our patients were in the age group of 20 to 60 years. The primary lesions were T1 and 7, T2 in 7 and recurrent in 9 patients. Only 7 patients had palpable groin nodes at presentation, all of which were pathologically negative. The median dose of implant was 50 Gy (range 40 to 60 Gy), using the LDR afterloading system and the Paris system of implant rules for dosimetry. Follow-up ranged from 4 to 117 months (median 24 months). Results: At last follow-up 18 of the 23 patients remained locally controlled with implant alone. Three patients failed only locally, 2 locoregionally and 1 only at the groin. Of the 5 patients who failed locally, 4 were successfully salvaged with partial penectomy and remained controlled when last seen. Local control with implant alone at 8 years was 70% by life table analysis. The patients had excellent functional and cosmetic outcome. We did not record any case of skin or softtissue necrosis. Only 2 patients developed meatal stenosis, both of which were treated endoscopically. Conclusion: Our results lead us to interpret that interstitial brachytherapy with Ir-192 offers excellent local control rates with preservation of organ and function. Penectomy can be reserved as a means for effective salvage. (orig.) [Deutsch] Ziel: Das Prinzip des Organerhalts gewinnt in der Onkologie zunehmend an Bedeutung. Ziel dieser Untersuchung war es, die Rolle der interstitiellen Brachytherapie mit Ir-192 zur Behandlung des fruehen und rezidivierten Peniskarzinoms zu

  19. The feasibility study and characterization of a two-dimensional diode array in “magic phantom” for high dose rate brachytherapy quality assurance

    Energy Technology Data Exchange (ETDEWEB)

    Espinoza, A.; Beeksma, B.; Petasecca, M.; Fuduli, I.; Porumb, C.; Cutajar, D.; Lerch, M. L. F.; Rosenfeld, A. B. [Centre for Medical Radiation Physics, University of Wollongong, New South Wales 2522 (Australia); Corde, S.; Jackson, M. [Department of Radiation Oncology, Prince of Wales Hospital, New South Wales 2031 (Australia)


    Purpose: High dose rate (HDR) brachytherapy is a radiation treatment technique capable of delivering large dose rates to the tumor. Radiation is delivered using remote afterloaders to drive highly active sources (commonly {sup 192}Ir with an air KERMA strength range between 20 000 and 40 000 U, where 1 U = 1 μGy m{sup 2}/h in air) through applicators directly into the patient's prescribed region of treatment. Due to the obvious ramifications of incorrect treatment while using such an active source, it is essential that there are methods for quality assurance (QA) that can directly and accurately verify the treatment plan and the functionality of the remote afterloader. This paper describes the feasibility study of a QA system for HDR brachytherapy using a phantom based two-dimensional 11 × 11 epitaxial diode array, named “magic phantom.”Methods: The HDR brachytherapy treatment plan is translated to the phantom with two rows of 10 (20 in total) HDR source flexible catheters, arranged above and below the diode array “magic plate” (MP). Four-dimensional source tracking in each catheter is based upon a developed fast iterative algorithm, utilizing the response of the diodes in close proximity to the {sup 192}Ir source, sampled at 100 ms intervals by a fast data acquisition (DAQ) system. Using a {sup 192}Ir source in a solid water phantom, the angular response of the developed epitaxial diodes utilized in the MP and also the variation of the MP response as a function of the source-to-detector distance (SDD) were investigated. These response data are then used by an iterative algorithm for source dwelling position determination. A measurement of the average transit speed between dwell positions was performed using the diodes and a fast DAQ.Results: The angular response of the epitaxial diode showed a variation of 15% within 360°, with two flat regions above and below the detector face with less than 5% variation. For SDD distances of between 5 and 30 mm

  20. Interstitial irradiation and hyperthermia for the treatment of recurrent malignant brain tumors. (United States)

    Sneed, P K; Stauffer, P R; Gutin, P H; Phillips, T L; Suen, S; Weaver, K A; Lamb, S A; Ham, B; Prados, M D; Larson, D A


    Between June 1987 and June 1989, 29 recurrent malignant gliomas or recurrent solitary brain metastases in 28 patients were treated in a Phase I study of interstitial irradiation and hyperthermia. Patient age ranged from 18 to 65 years, and the Karnofsky Performance Status scores ranged from 40 to 90%. There were 13 glioblastomas, 10 anaplastic astrocytomas, 3 melanomas, and 3 adenocarcinomas. Catheters were implanted stereotactically after computed tomography-based preplanning. Hyperthermia was administered before and after brachytherapy, using one to six 2450- or 915-MHz helical coil microwave antennas and one to three multisensor fiberoptic thermometry probes. The goal was to heat as much of the tumor as possible to 42.5 degrees C for 30 minutes. Within 30 minutes after the first hyperthermia treatment, implant catheters were afterloaded with high-activity iodine-125 seeds delivering tumor doses of 32.6 to 61.0 Gy. Most patients had no sensation of heating. Complications included seizures in 5 patients, reversible neurological changes in 9 patients, a scalp burn in 1, and infections in 3. Of 28 evaluable 2-month follow-up scans, 11 showed definite improvement in the radiological appearance of the tumor, 4 were slightly improved, 7 were stable, and 6 showed tumor progression. Ten patients underwent reoperation for persistent tumor and/or necrosis. Eleven of 28 patients are alive 40 to 97 weeks after treatment. Thirteen patients died of a brain tumor, 2 died of extracranial melanoma metastases, 1 died of new brain melanoma metastases, and 1 died of a pulmonary embolus. The median survival was 55 weeks overall. Median survival has not yet been reached for the anaplastic astrocytoma subgroup. We conclude that interstitial brain hyperthermia using helical coil microwave antennas is technically feasible. The level of toxicity is acceptable, and the computed tomographic response rate is encouraging.

  1. Technique for routine output verification of Leipzig applicators with a well chamber. (United States)

    Pérez-Calatayud, J; Granero, D; Ballester, F; Crispín, V; Van der Laarse, R


    The H-type Leipzig applicators are accessories of the microSelectron-HDR system (Nucletron, Veenendaal, The Netherlands) for treatment of superficial malignancies. Recently, the dose rate distributions in liquid water for the whole set of applicators using both source models available for the microSelectron-HDR afterloaders have been obtained by means of the experimentally validated Monte Carlo (MC) code GEANT4. Also an output table (cGy/hU) at 3 mm depth on the applicator central axis was provided. The output verification of these applicators by the user, prior to their clinical use, present practical problems: small detectors such as thermoluminescent dosimeters or parallel-plate ionization chambers are not easily used for verification in a clinical environment as they require a rigid setup with the Leipzig applicator and a phantom. In contrast, well-type ionization chambers are readily available in radiotherapy departments. This study presents a technique based on the HDR1000Plus well chamber (Standar Imaging) measurements with a special insert, which allows the output verification of the H-type Leipzig applicators on a routine basis. This technique defines correspondence factors (CF) between the in water dose rate output of the Leipzig applicators (cGy/hU) obtained with MC and the reading on the well chamber with the special insert, normalized to the HDR calibration factor with the HDR insert and to the source strength. To commission the applicators (with the well chamber and the special insert used), the physicist should check if the CF value agrees with its tabulated values presented in this work. If the differences are within 5% the tabulated output values can be used in clinical dosimetry. This technique allows the output validation of the Leipzig applicators with a well chamber widely used for HDR Ir-192 source strength measurements. It can easily be adapted to other types of well chambers for HDR source output verification.

  2. Uterine cervix cancer associated with pregnancy:Report of 5 cases%妊娠相关性宫颈癌5例临床治疗体会

    Institute of Scientific and Technical Information of China (English)

    陆云燕; 刘蓉; 徐海波


    Objective:To explore the diangnosis , treatment and prognosis of cervical cancer associated with pregnancy. Methods: From January 2003 to November 2009,5 patients were treated with surgery, radiotherapy and chemotherapy. Regimens chemotherapy with VBP, TP and afterloading intracavitary treatment of cobalt before surgery, TP before external irradiation were performed. Results:Aee patients were with worse pathological differentiation , the right diagnosis all delayed , all 5 patients had rapidly progressive disease, 2 patients dead in 6 months, 1 patient dead in 12 months, 1 patient dead in 17 months. Conclusion:The prognosis of cervical cancer associated with pregnancy is very poor,early diagnosis is very important.%目的:探讨妊娠相关性宫颈癌的诊断、治疗及预后.方法:从2003年1月至2009年11月对收治的5例妊娠相关性宫颈癌患者进行手术、化疗、放疗.术前采用VBP、TP方案及后装治疗,根治性放疗前采用TP方案化疗.结果:5例妊娠相关性宫颈癌分化程度低,发现时病期较晚,病情发展较快,2例6月内死亡,1例12个月死亡,1例17个月死亡.结论:妊娠相关性宫颈癌预后差,早期诊断很重要,治疗方案个体化.

  3. A workshop on developing risk assessment methods for medical use of radioactive material. Volume 1: Summary

    Energy Technology Data Exchange (ETDEWEB)

    Tortorelli, J.P. [ed.] [Lockheed Idaho Technologies Co., Idaho Falls, ID (United States)


    A workshop was held at the Idaho National Engineering Laboratory, August 16--18, 1994 on the topic of risk assessment on medical devices that use radioactive isotopes. Its purpose was to review past efforts to develop a risk assessment methodology to evaluate these devices, and to develop a program plan and a scoping document for future methodology development. This report contains a summary of that workshop. Participants included experts in the fields of radiation oncology, medical physics, risk assessment, human-error analysis, and human factors. Staff from the US Nuclear Regulatory Commission (NRC) associated with the regulation of medical uses of radioactive materials and with research into risk-assessment methods participated in the workshop. The workshop participants concurred in NRC`s intended use of risk assessment as an important technology in the development of regulations for the medical use of radioactive material and encouraged the NRC to proceed rapidly with a pilot study. Specific recommendations are included in the executive summary and the body of this report. An appendix contains the 8 papers presented at the conference: NRC proposed policy statement on the use of probabilistic risk assessment methods in nuclear regulatory activities; NRC proposed agency-wide implementation plan for probabilistic risk assessment; Risk evaluation of high dose rate remote afterloading brachytherapy at a large research/teaching institution; The pros and cons of using human reliability analysis techniques to analyze misadministration events; Review of medical misadministration event summaries and comparison of human error modeling; Preliminary examples of the development of error influences and effects diagrams to analyze medical misadministration events; Brachytherapy risk assessment program plan; and Principles of brachytherapy quality assurance.

  4. Effect of transcatheter aortic valve implantation on intraoperative left ventricular end-diastolic pressure. (United States)

    Toyota, Kosaku; Ota, Takashi; Nagamine, Katsutoshi; Koide, Yasuhiro; Nomura, Takeshi; Yamanaka, Futoshi; Shishido, Koki; Tanaka, Masashi; Saito, Shigeru


    Transcatheter aortic valve implantation (TAVI) for patients with aortic stenosis is a less invasive alternative to surgical aortic valve replacement. Despite this, careful anesthetic management, especially strict control of blood pressure and fluid management, is necessary. During TAVI, normalization of left ventricular afterload due to aortic balloon valvuloplasty and prosthetic valve deployment is expected to result in rapid improvement of systolic function and consequent improvement in diastolic function. However, the early effect of TAVI on left ventricular diastolic function is less clear. We hypothesized that TAVI induces a rapid decrease in left ventricular end-diastolic pressure (LVEDP) after valve deployment. This retrospective observational study included 71 patients who had undergone TAVI using the transfemoral approach with a balloon-expandable valve under general anesthesia. Intraoperative LVEDP was measured using an intracardiac catheter. The severity of residual aortic regurgitation (AR) was assessed using the Sellers criteria. The mean (SD) LVEDP was 17.8 (5.3) mmHg just before TAVI and increased significantly to 27.3 (8.2) mmHg immediately after prosthetic valve deployment (p < 0.0001). The change in LVEDP was 8.7 (8.6) mmHg in patients with low residual AR (Sellers ≤1) and 11.0 (7.1) mmHg in those with high residual AR (Sellers ≥2); however, this difference was not significant. No correlation was found between the LVEDP change and intraoperative fluid balance. In conclusion, LVEDP increased significantly in the early period after valve deployment during TAVI, regardless of residual AR severity. It was suggested that the tolerability of fluid load could be reduced at that time.

  5. Artificial Heart Fluid Dynamics. (United States)

    Mussivand, Tofigh Varcaneh

    Flow characteristics within pneumatic, pulsatile, and pusher plate prosthetic hearts were studied. The blood pumps evaluated were duplicates of pumps used for in vivo calf and for clinical implantation at the Cleveland Clinic Foundation. Human dura mater bioprosthetic, caged disk, and Bjork-Shiley tilting disk valves were employed in the pumps. Dual camera video tape and synchronized still photography were used to study flow patterns. Diffused light and a planar laser source provided illumination. The laser light was fanned into a plane with a thickness of 0.2 mm to 10 mm. Magnesium oxide and Amberlite particles were used as tracers. Aqueous-glycerol, aqueous-sucrose solutions and mineral oil were used as blood analog fluids. Inflow, outflow, drive, and afterload pressures, diaphragm motion, cardiac output, and heart rate were measured and recorded. An electrical circuit was developed to synchronize pump diaphragm motion with captured images of flow trajectories. After digitizing the trajectories, velocities, global and local turbulence, and shear stresses were obtained. Disturbed and recirculating zones were identified. Qualitative and quantitative analyses were performed using data obtained from the digitization of flow trajectories. Simultaneous turbulence and stasis were observed during most phases of the cardiac cycles in all the pumps tested. A maximum Reynold's shear stress of 2889 dynes/cm ^2 occurred at 120 beats per minute (bpm). The peak velocity was 146 cm/sec during systole. The identified regions of recirculation, low velocity and disturbed flow were shown to correlate with thrombosed areas of explanted blood pumps. The maximum calculated turbulence intensity was 106 cm/sec which occurred at 120 bpm during systole.

  6. Non-invasive estimation and control of inlet pressure in an implantable rotary blood pump for heart failure patients. (United States)

    Alomari, A H; Savkin, A V; Ayre, P J; Lim, E; Mason, D G; Salamonsen, R F; Fraser, J F; Lovell, N H


    We propose a dynamical model for mean inlet pressure estimation in an implantable rotary blood pump during the diastolic period. Non-invasive measurements of pump impeller rotational speed (ω), motor power (P), and pulse width modulation signal acquired from the pump controller were used as inputs to the model. The model was validated over a wide range of speed ramp studies, including (i) healthy (C1), variations in (ii) heart contractility (C2); (iii) afterload (C2, C3, C4), and (iv) preload (C5, C6, C7). Linear regression analysis between estimated and extracted mean inlet pressure obtained from in vivo animal data (greyhound dogs, N = 3) resulted in a highly significant correlation coefficients (R(2) = 0.957, 0.961, 0.958, 0.963, 0.940, 0.946, and 0.959) and mean absolute errors of (e = 1.604, 2.688, 3.667, 3.990, 2.791, 3.215, and 3.225 mmHg) during C1, C2, C3, C4, C5, C6, and C7, respectively. The proposed model was also used to design a controller to regulate mean diastolic pump inlet pressure using non-invasively measured ω and P. In the presence of model uncertainty, the controller was able to track and settle to the desired input within a finite number of sampling periods and minimal error (0.92 mmHg). The model developed herein will play a crucial role in developing a robust control system of the pump that detects and thus avoids undesired pumping states by regulating the inlet pressure within a predefined physiologically realistic limit.

  7. Mechanical analysis of single myocyte contraction in a 3-D elastic matrix.

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    John Shaw

    Full Text Available BACKGROUND: Cardiac myocytes experience mechanical stress during each heartbeat. Excessive mechanical stresses under pathological conditions cause functional and structural remodeling that lead to heart diseases, yet the precise mechanisms are still incompletely understood. To study the cellular and molecular level mechanotransduction mechanisms, we developed a new 'cell-in-gel' experimental system to exert multiaxial (3-D stresses on a single myocyte during active contraction. METHODS: Isolated myocytes are embedded in an elastic hydrogel to simulate the mechanical environment in myocardium (afterload. When electrically stimulated, the in-gel myocyte contracts while the matrix resists shortening and broadening of the cell, exerting normal and shear stresses on the cell. Here we provide a mechanical analysis, based on the Eshelby inclusion problem, of the 3-D strain and stress inside and outside the single myocyte during contraction in an elastic matrix. RESULTS: (1 The fractional shortening of the myocyte depends on the cell's geometric dimensions and the relative stiffness of the cell to the gel. A slender or softer cell has less fractional shortening. A myocyte of typical dimensions embedded in a gel of similar elastic stiffness can contract only 20% of its load-free value. (2 The longitudinal stress inside the cell is about 15 times the transverse stress level. (3 The traction on the cell surface is highly non-uniform, with a maximum near its ends, showing 'hot spots' at the location of intercalated disks. (4 The mechanical energy expenditure of the myocyte increases with the matrix stiffness in a monotonic and nonlinear manner. CONCLUSION: Our mechanical analyses provide analytic solutions that readily lend themselves to parametric studies. The resulting 3-D mapping of the strain and stress states serve to analyze and interpret ongoing cell-in-gel experiments, and the mathematical model provides an essential tool to decipher and quantify

  8. The transit dose component of high dose rate brachytherapy: Direct measurements and clinical implications

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    Bastin, K.T.; Podgorsak, M.B.; Thomadsen, B.R. (Univ. of Wisconsin Hospitals and Clinics, Madison, WI (United States))


    The purpose was to measure the transit dose produced by a moving high dose rate brachytherapy source and assess its clinical significance. The doses produced from source movement during Ir-192 HDR afterloading were measured using calibrated thermoluminescent dosimeter rods. Transit doses at distances of 0.5-4.0 cm from an endobronchial applicator were measured using a Lucite phantom accommodating 1 x 1 x 6 mm thermoluminescent rods. Surface transit dose measurements were made using esophageal and endobronchial catheters, a gynecologic tandem, and an interstitial needle. No difference was detected in thermoluminescent dosimeter rod responses to 4 MV and Ir-192 spectra (427 nC/Gy) in a range of dose between 2 and 300 cGy. The transit dose at 0.5 cm from an endobronchial catheter was 0.31 cGy/(Curie-fraction) and followed an inverse square fall-off with increasing distance. Surface transit doses ranged from 0.38 cGy/(Curie-fraction) for an esophageal catheter to 1.03 cGy/(Curie-fraction) for an endobronchial catheter. Source velocity is dependent on the interdwell distance and varies between 220-452 mm/sec. A numeric algorithm was developed to calculate total transit dose, and was based on a dynamic point approximation for the moving high dose rate source. This algorithm reliably predicted the empirical transit doses and demonstrated that total transit dose is dependent on source velocity, number of fractions, and source activity. Surface transit doses are dependent on applicator diameter and wall material and thickness. Total transit doses within or outside the desired treatment volume are typically <100 cGy, but may exceed 200 cGy when using a large number of fractions with a high activity source. 9 refs., 8 figs., 1 tab.

  9. Maximum shortening velocity of lymphatic muscle approaches that of striated muscle. (United States)

    Zhang, Rongzhen; Taucer, Anne I; Gashev, Anatoliy A; Muthuchamy, Mariappan; Zawieja, David C; Davis, Michael J


    Lymphatic muscle (LM) is widely considered to be a type of vascular smooth muscle, even though LM cells uniquely express contractile proteins from both smooth muscle and cardiac muscle. We tested the hypothesis that LM exhibits an unloaded maximum shortening velocity (Vmax) intermediate between that of smooth muscle and cardiac muscle. Single lymphatic vessels were dissected from the rat mesentery, mounted in a servo-controlled wire myograph, and subjected to isotonic quick release protocols during spontaneous or agonist-evoked contractions. After maximal activation, isotonic quick releases were performed at both the peak and plateau phases of contraction. Vmax was 0.48 ± 0.04 lengths (L)/s at the peak: 2.3 times higher than that of mesenteric arteries and 11.4 times higher than mesenteric veins. In cannulated, pressurized lymphatic vessels, shortening velocity was determined from the maximal rate of constriction [rate of change in internal diameter (-dD/dt)] during spontaneous contractions at optimal preload and minimal afterload; peak -dD/dt exceeded that obtained during any of the isotonic quick release protocols (2.14 ± 0.30 L/s). Peak -dD/dt declined with pressure elevation or activation using substance P. Thus, isotonic methods yielded Vmax values for LM in the mid to high end (0.48 L/s) of those the recorded for phasic smooth muscle (0.05-0.5 L/s), whereas isobaric measurements yielded values (>2.0 L/s) that overlapped the midrange of values for cardiac muscle (0.6-3.3 L/s). Our results challenge the dogma that LM is classical vascular smooth muscle, and its unusually high Vmax is consistent with the expression of cardiac muscle contractile proteins in the lymphatic vessel wall.

  10. The reservoir-wave approach to characterize pulmonary vascular-right ventricular interactions in humans. (United States)

    Ghimire, Anukul; Andersen, Mads J; Burrowes, Lindsay M; Bouwmeester, J Christopher; Grant, Andrew D; Belenkie, Israel; Fine, Nowell M; Borlaug, Barry A; Tyberg, John V


    Using the reservoir-wave approach (RWA) we previously characterized pulmonary vasculature mechanics in a normal canine model. We found reflected backward-traveling waves that decrease pressure and increase flow in the proximal pulmonary artery (PA). These waves decrease right ventricular (RV) afterload and facilitate RV ejection. With pathological alterations to the pulmonary vasculature, these waves may change and impact RV performance. Our objective in this study was to characterize PA wave reflection and the alterations in RV performance in cardiac patients, using the RWA. PA pressure, Doppler-flow velocity, and pulmonary arterial wedge pressure were measured in 11 patients with exertional dyspnea. The RWA was employed to analyze PA pressure and flow; wave intensity analysis characterized PA waves. Wave-related pressure was partitioned into two components: pressures due to forward-traveling and to backward-traveling waves. RV performance was assessed by examining the work done in raising reservoir pressure and that associated with the wave components of systolic PA pressure. Wave-related work, the mostly nonrecoverable energy expended by the RV to eject blood, tended to vary directly with mean PA pressure. Where PA pressures were lower, there were pressure-decreasing/flow-increasing backward waves that aided RV ejection. Where PA pressures were higher, there were pressure-increasing/flow-decreasing backward waves that impeded RV ejection. Pressure-increasing/flow-decreasing backward waves were responsible for systolic notches in the Doppler flow velocity profiles in patients with the highest PA pressure. Pulmonary hypertension is characterized by reflected waves that impede RV ejection and an increase in wave-related work. The RWA may facilitate the development of therapeutic strategies.

  11. Attenuated fatigue in slow twitch skeletal muscle during isotonic exercise in rats with chronic heart failure.

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    Morten Munkvik

    Full Text Available During isometric contractions, slow twitch soleus muscles (SOL from rats with chronic heart failure (chf are more fatigable than those of sham animals. However, a muscle normally shortens during activity and fatigue development is highly task dependent. Therefore, we examined the development of skeletal muscle fatigue during shortening (isotonic contractions in chf and sham-operated rats. Six weeks following coronary artery ligation, infarcted animals were classified as failing (chf if left ventricle end diastolic pressure was >15 mmHg. During isoflurane anaesthesia, SOL with intact blood supply was stimulated (1s on 1s off at 30 Hz for 15 min and allowed to shorten isotonically against a constant afterload. Muscle temperature was maintained at 37°C. In resting muscle, maximum isometric force (F(max and the concentrations of ATP and CrP were not different in the two groups. During stimulation, F(max and the concentrations declined in parallel sham and chf. Fatigue, which was evident as reduced shortening during stimulation, was also not different in the two groups. The isometric force decline was fitted to a bi-exponential decay equation. Both time constants increased transiently and returned to initial values after approximately 200 s of the fatigue protocol. This resulted in a transient rise in baseline tension between stimulations, although this effect which was less prominent in chf than sham. Myosin light chain 2s phosphorylation declined in both groups after 100 s of isotonic contractions, and remained at this level throughout 15 min of stimulation. In spite of higher energy demand during isotonic than isometric contractions, both shortening capacity and rate of isometric force decline were as well or better preserved in fatigued SOL from chf rats than in sham. This observation is in striking contrast to previous reports which have employed isometric contractions to induce fatigue.

  12. Experimental exposure to diesel exhaust increases arterial stiffness in man

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    Newby David E


    Full Text Available Abstract Introduction Exposure to air pollution is associated with increased cardiovascular morbidity, although the underlying mechanisms are unclear. Vascular dysfunction reduces arterial compliance and increases central arterial pressure and left ventricular after-load. We determined the effect of diesel exhaust exposure on arterial compliance using a validated non-invasive measure of arterial stiffness. Methods In a double-blind randomized fashion, 12 healthy volunteers were exposed to diesel exhaust (approximately 350 μg/m3 or filtered air for one hour during moderate exercise. Arterial stiffness was measured using applanation tonometry at the radial artery for pulse wave analysis (PWA, as well as at the femoral and carotid arteries for pulse wave velocity (PWV. PWA was performed 10, 20 and 30 min, and carotid-femoral PWV 40 min, post-exposure. Augmentation pressure (AP, augmentation index (AIx and time to wave reflection (Tr were calculated. Results Blood pressure, AP and AIx were generally low reflecting compliant arteries. In comparison to filtered air, diesel exhaust exposure induced an increase in AP of 2.5 mmHg (p = 0.02 and in AIx of 7.8% (p = 0.01, along with a 16 ms reduction in Tr (p = 0.03, 10 minutes post-exposure. Conclusion Acute exposure to diesel exhaust is associated with an immediate and transient increase in arterial stiffness. This may, in part, explain the increased risk for cardiovascular disease associated with air pollution exposure. If our findings are confirmed in larger cohorts of susceptible populations, this simple non-invasive method of assessing arterial stiffness may become a useful technique in measuring the impact of real world exposures to combustion derived-air pollution.


    Institute of Scientific and Technical Information of China (English)

    段海; 汪晓阳; 张希博; 柳超; 彭湃


    通过对沈阳市府恒隆广场350 m 高塔楼顶部的皇冠钢结构施工过程进行模拟分析,简要介绍了复杂钢结构施工过程模拟分析的方法、步骤、施工阶段划分的原则、条件假定、临时支撑的反力分析、加固结构的承载力分析以及后装缺口的变形控制等,通过施工阶段模拟分析的方法,来确定施工方案、优化施工顺序,确保施工方案的可行性、科学性,同时避免盲目施工所带来的结构安全和质量隐患。%ABSTRACT:Through the simulation analysis of the construction process of steel crown structure at the top of 350-meter-high building of Hang Lung Plaza in Shenyang,this paper briefly introduced the simulation analysis of the construction process of complex steel structure in terms of the approaches, the steps,the principles of the construction stage division,the assumption of conditions,the reaction force analysis of temporary supports,the bearing capacity analysis of the reinforced structure,as well as the analysis of the deformation control of the afterloading gaps and so on.The construction scheme was identified and the construction sequence was optimized through simulation analysis of construction process,thus the feasibility and scientificity of the construction scheme was confirmed which could avoid the quality problems caused by blind construction.

  14. Population pharmacokinetics of olprinone in healthy male volunteers

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    Kunisawa T


    Full Text Available Takayuki Kunisawa,1 Hidefumi Kasai,2 Makoto Suda,2 Manabu Yoshimura,3 Ami Sugawara,3 Yuki Izumi,3 Takafumi Iida,3 Atsushi Kurosawa,3 Hiroshi Iwasaki3 1Surgical Operation Department, Asahikawa Medical University Hospital, Hokkaido, Japan; 2Clinical Study Management Division, Bell Medical Solutions Inc, Tokyo, Japan; 3Department of Anesthesiology and Critical Care Medicine, Asahikawa Medical University, Hokkaido, Japan Background: Olprinone decreases the cardiac preload and/or afterload because of its vasodilatory effect and increases myocardial contractility by inhibiting phosphodiesterase III. Purpose: The objective of this study was to characterize the population pharmacokinetics of olprinone after a single continuous infusion in healthy male volunteers. Methods: We used 500 plasma concentration data points collected from nine healthy male volunteers for the study. The population pharmacokinetic analysis was performed using the nonlinear mixed effect model (NONMEM® software. Results: The time course of plasma concentration of olprinone was best described using a two-compartment model. The final pharmacokinetic parameters were total clearance (7.37 mL/minute/kg, distribution volume of the central compartment (134 mL/kg, intercompartmental clearance (7.75 mL/minute/kg, and distribution volume of the peripheral compartment (275 mL/kg. The interindividual variability in the total clearance was 12.4%, and the residual error variability (exponential and additive were 22.2% and 0.129 (standard deviation. The final pharmacokinetic model was assessed using a bootstrap method and visual predictive check. Conclusion: We developed a population pharmacokinetic model of olprinone in healthy male adults. The bootstrap method and visual predictive check showed that this model was appropriate. Our results might be used to develop the population pharmacokinetic model in patients. Keywords: phosphodiesterase III inhibitor, men, pharmacokinetic model

  15. Altered Right Ventricular Kinetic Energy Work Density and Viscous Energy Dissipation in Patients with Pulmonary Arterial Hypertension: A Pilot Study Using 4D Flow MRI.

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    Q Joyce Han

    Full Text Available Right ventricular (RV function has increasingly being recognized as an important predictor for morbidity and mortality in patients with pulmonary arterial hypertension (PAH. The increased RV after-load increase RV work in PAH. We used time-resolved 3D phase contrast MRI (4D flow MRI to derive RV kinetic energy (KE work density and energy loss in the pulmonary artery (PA to better characterize RV work in PAH patients.4D flow and standard cardiac cine images were obtained in ten functional class I/II patients with PAH and nine healthy subjects. For each individual, we calculated the RV KE work density and the amount of viscous dissipation in the PA.PAH patients had alterations in flow patterns in both the RV and the PA compared to healthy subjects. PAH subjects had significantly higher RV KE work density than healthy subjects (94.7±33.7 mJ/mL vs. 61.7±14.8 mJ/mL, p = 0.007 as well as a much greater percent PA energy loss (21.1±6.4% vs. 2.2±1.3%, p = 0.0001 throughout the cardiac cycle. RV KE work density and percent PA energy loss had mild and moderate correlations with RV ejection fraction.This study has quantified two kinetic energy metrics to assess RV function using 4D flow. RV KE work density and PA viscous energy loss not only distinguished healthy subjects from patients, but also provided distinction amongst PAH patients. These metrics hold promise as imaging markers for RV function.

  16. Feasibility and safety of outpatient brachytherapy in 37 patients with brain tumors using the GliaSite Radiation Therapy System. (United States)

    Chino, Kazumi; Silvain, Daniel; Grace, Ana; Stubbs, James; Stea, Baldassarre


    Temporary, low dose rate brachytherapy to the margins of resected brain tumors, using a balloon catheter system (GliaSite Radiation Therapy System) and liquid I-125 radiation source (Iotrex), began in 2002 at the University of Arizona Medical Center. Initially, all patients were treated on an inpatient basis. For patient convenience, we converted to outpatient therapy. In this article we review the exposure data and safety history for the 37 patients treated as outpatients. Proper patient selection and instruction is crucial to having a successful outpatient brachytherapy program. A set of evaluation criteria and patient instructions were developed in compliance with the U.S. Nuclear Regulatory Commission's document NUREG-1556 Volume 9 (Appendix U) and Arizona State Nuclear regulatory guidelines, which specify acceptable exposure rates for outpatient release in this setting. Of the 37 patients monitored, 26 patients were treated for recurrent glioblastoma multiforme (GBM), six for primary GBM, and five for metastatic brain tumors. All 37 patients and their primary caregivers gave signed agreement to follow a specific set of instructions and were released for the duration of brachytherapy (3-7 days). The typical prescription dose was 60 Gy delivered at 0.5 cm from the balloon surface. Afterloaded activities in these patients ranged from 90.9 to 750.0 mCi and measured exposure rates at 1 m from the head were less than 14 mR/h. The mean exposure to the caretaker measured by personal radiation Landauer Luxel + whole body dosimeters for 25 caretakers was found to be 9.6 mR, which was significantly less than the mean calculated exposure of 136.8 mR. For properly selected patients, outpatient brachytherapy is simple and can be performed within established regulatory guidelines.

  17. Retrospective study of neoadjuvant versus adjuvant radiochemotherapy in locally advanced noninflammatory breast cancer. Survival advantage in cT2 category by neoadjuvant radiochemotherapy

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    Roth, Stephan Ludwig; Lang, Innokentij; Budach, Wilfried [Dept. of Radiotherapy, Univ. of Duesseldorf (Germany); Audretsch, Werner [Breast Center, Marien-Hospital, Duesseldorf (Germany); Bojar, Hans [Inst. for Oncologic Chemistry, Univ. of Duesseldorf (Germany); Willers, Reinhart [Computer Center, Univ. of Duesseldorf (Germany)


    Purpose: this retrospective study compares patients treated between 1991 and 1998 with neoadjuvant radiotherapy {+-} chemotherapy (RCT) or adjuvant RCT for locally advanced noninflammatory breast cancers (LABC) in terms of pathologic complete response (pCR), 10-year relapse-free (RFS), and overall survival (OS). Patients and methods: preoperative RCT in 315 and adjuvant RCT in 329 cases consisted in 50 Gy (5 x 2 Gy/week) to the breast and the supra-/infraclavicular lymph nodes. 101 neoadjuvant patients received - in case of breast conservation - a 10-Gy interstitial boost with {sup 192}Ir afterloading before and 214 neoadjuvant patients a preoperative electron boost after external-beam radiotherapy. In the neoadjuvant RCT group, chemotherapy was applied prior to radiotherapy in 192 patients, and simultaneously in 113; ten had no chemotherapy. In the adjuvant RCT group, chemotherapy was applied to 44 patients before surgery and to 166 after surgery; 119 had no chemotherapy. Results: breast conservation became possible in 50.8% after neoadjuvant RCT for LABC with a pCR rate at surgery of 29.2%. A complete nodal remission (pNO) after RCT was observed in 56% (89/159) of the cN+ (clinically node-positive) neoadjuvant patients. There were trends in favor of preoperative RCT for RFS and OS (hazard ratio [HR] = 0.85; p = 0.09 for RFS; HR = 0.8130; p = 0.1037 for OS). For patients with cT2 tumors the RFS and OS were statistically significantly better (HR = 0.5090; p = 0.0130 for RFS; HR = 0.4390; p = 0.0026 for OS) after neoadjuvant compared to adjuvant RCT. Conclusion: neoadjuvant RCT achieved a pCR rate of 29.2% and a statistically significantly better RFS and OS in patients with cT2-category breast cancer. (orig.)

  18. Salvage surgery for nasopharyngeal cancer

    Institute of Scientific and Technical Information of China (English)

    Raymond K.Tsang; William I.Wei


    Nasopharyngeal carcinoma (NPC) is a special type of head and neck cancer with a widely variable geographical variation in incidence.The central location of the tumor inside the head coupled with the radiosensitivity of the tumor to radiation made radiation therapy the first choice in primary treatment of NPC.Advances in radiotherapy and chemotherapy have markedly improved the local control of NPC.Unfortunately, a small but significant number of patients still suffered from loco-regional failures that would be amenable to re-treatment.Traditional form of retreatment was to employ a second course of radiation.The efficacy of re-irradiation to treat local of regional recurrent NPC has been suboptimal.Moreover, the local tissue had already received a high dose of radiation and the second radiation could result in radiation toxicities to the local tissue, leading to significant complications.Surgical salvage, on the other hand, could spare the patients from complications of retreatment.Due to the difficult access of the nasopharynx, various surgical approaches had been devised for nasopharyngectomy.The maxillary swing approach had the largest published experience with over 300 cases from various centers.In the recent decade, the endoscopic approach with or without robotic assistance had gained popularity for resecting small, centrally located recurrences.This minimally invasive approach further reduced the morbidity for treating locally recurrent NPC.Nodal recurrences had been a rare entity after the introduction of modern radiotherapy technique and concurrent chemotherapy.Treatment of nodal failure with second radiation has dismal results.Surgical removal of the lymph node harboring the recurrence should be in the form of a formal radical neck dissection.In cases of extensive nodal recurrence where microscopic disease may be present after a formal neck dissection, additional radiotherapy can be delivered with after-loading brachytherapy.Surgical treatment played a

  19. LV reverse remodeling imparted by aortic valve replacement for severe aortic stenosis; is it durable? A cardiovascular MRI study sponsored by the American Heart Association

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    Caruppannan Ketheswaram


    Full Text Available Abstract Background In patients with severe aortic stenosis (AS, long-term data tracking surgically induced effects of afterload reduction on reverse LV remodeling are not available. Echocardiographic data is available short term, but in limited fashion beyond one year. Cardiovascular MRI (CMR offers the ability to serially track changes in LV metrics with small numbers due to its inherent high spatial resolution and low variability. Hypothesis We hypothesize that changes in LV structure and function following aortic valve replacement (AVR are detectable by CMR and once triggered by AVR, continue for an extended period. Methods Tweny-four patients of which ten (67 ± 12 years, 6 female with severe, but compensated AS underwent CMR pre-AVR, 6 months, 1 year and up to 4 years post-AVR. 3D LV mass index, volumetrics, LV geometry, and EF were measured. Results All patients survived AVR and underwent CMR 4 serial CMR's. LVMI markedly decreased by 6 months (157 ± 42 to 134 ± 32 g/m2, p 2. Similarly, EF increased pre to post-AVR (55 ± 22 to 65 ± 11%,(p 2. LV stroke volume increased rapidly from pre to post-AVR (40 ± 11 to 44 ± 7 ml, p Conclusion After initial beneficial effects imparted by AVR in severe AS patients, there are, as expected, marked improvements in LV reverse remodeling. Via CMR, surgically induced benefits to LV structure and function are durable and, unexpectedly express continued, albeit markedly incomplete improvement through 4 years post-AVR concordant with sustained improved clinical status. This supports down-regulation of both mRNA and MMP activity acutely with robust suppression long term.

  20. Pharmacokinetics and pharmacodynamics of intravenous inotropic agents. (United States)

    Lehtonen, Lasse A; Antila, Saila; Pentikäinen, Pertti J


    Positive inotropic drugs have various mechanisms of action. Long-term use of cyclic adenosine monophosphate (cAMP)-dependent drugs has adverse effects on the prognosis of heart failure patients, whereas digoxin has neutral effect on mortality. There are, however, little data on the effects of intravenous inotropic drugs on the outcome of patients. Intravenous inotropic agents are used to treat cardiac emergencies and refractory heart failure. beta-Adrenergic agonists are rapid acting and easy to titrate, with short elimination half-life. However, they increase myocardial oxygen consumption and are thus hazardous during myocardial ischaemia. Furthermore they may promote myocyte apoptosis. Phosphodiesterase (PDE) III inhibiting drugs (amrinone, milrinone and enoximone) increase contractility by reducing the degradation of cAMP. In addition, they reduce both preload and afterload via vasodilation. Short-term use of intravenous milrinone is not associated with increased mortality, and some symptomatic benefit may be obtained when it is used in refractory heart failure. Furthermore, PDE III inhibitors facilitate weaning from the cardiopulmonary bypass machine after cardiac surgery. Levosimendan belongs to a new group of positive inotropic drugs, the calcium sensitisers. It has complex pharmacokinetics and long-lasting haemodynamic effects as a result of its active metabolites. In comparative trials, it has been better tolerated than the most widely used beta-agonist inotropic drug, dobutamine. The pharmacokinetics of the intravenous inotropic drugs might sometimes greatly modify and prolong the response to the therapy, for example because of long-acting active metabolites. These drugs display considerable differences in their pharmacokinetics and pharmacodynamics, and the selection of the most appropriate inotropic drug for each patient should be based on careful consideration of the clinical status of the patient and on the pharmacology of the drug.

  1. Influence of nifedipine on left ventricular perfusion and function in patients with unstable angina: Evaluation with radionuclide techniques

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    Wall, E.E. van der; Kerkkamp, H.J.; Simoons, M.L.; Rijk, P.P. van; Reiber, J.H.C.; Bom, N.; Lubsen, J.C.; Lie, K.I.


    In 1981, a large, double-blind, randomized trial was started in The Netherlands to evaluate the therapeutic effects of nifedipine and/or metoprolol in patients with unstable angina. This study has been called the Holland Interuniversity Nifedipine/metoprolol Trial (HINT) and required several hundred patients to establish potential therapeutic effects. From December 1982 to January 1984 the effects of nifedipine on left ventricular (LV) performance in a subgroup of 52 HINT patients were studied using radionuclide techniques. All patients (23 on nifedipine, 29 controls) underwent thallium-201 scintigraphy or radionuclide angiography just before and 48 h after the start of experimental medication. The radionuclide angiographic studies were also performed at 1 and 4 h after treatment. Nifedipine did not influence the incidence of disapperance of perfusion defects on the 48-h thallium images. No significant differences in overall LV ejections fraction (EF) were seen at any time between nifedipine-treated patients and controls. However, paired observations in 37 patients showed improvement of LVEF after 48 h in 8 patients on nifedipine and in only 1 control patient. Scintigraphic measurements on admission were not related to clinical outcome after 48 h. Concomitant administration of metoprolol did not influence LVEF in either group. It is concluded that nifedipine improves LVEF after 48 h in a subset of patients with unstable angina without affecting myocardial perfusion. This finding indicates that nifedipine has a predominant effect on afterload reduction in patients with unstable angina. Also, early scintigraphic measurements had no significant predictive value for subsequent cardiac events.

  2. Dosimetric comparison between three dimensional treatment planning system, Monte Carlo simulation and gel dosimetry in nasopharynx phantom for high dose rate brachytherapy

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    Zeynab Fazli


    Full Text Available Purpose: For the treatment of nasopharnx carcinoma (NPC using brachytherapy methods and high-energy photon sources are common techniques. In the common three dimensional (3D treatments planning, all of the computed tomography images are assumed homogeneous. This study presents the results of Monte Carlo calculations for non-homogeneous nasopharynx phantom, MAGICA normoxic gel dosimetry and 3D treatment planning system (TPS. Materials and Methods: The head phantom was designed with Plexiglas cylinder, head bone, and nasopharynx brachytherapy silicon applicator. For the simulations, version 5 of the Monte Carlo N-particle transport code (MCNP5 was used. 3D treatment planning was performed in Flexiplan software. A normoxic radiosensitive polymer gel was fabricated under normal atmospheric conditions and poured into test tubes (for calibration curve and the head phantom. In addition, the head phantom was irradiated with Flexitron afterloader brachytherapy machine with 192 Ir source. To obtain calibration curves, 11 dosimeters were irradiated with dose range of 0-2000 cGy. Evaluations of dosimeters were performed on 1.5T scanner. Results: Two-dimensional iso-dose in coronal plan at distances of z = +0.3, –0.3 cm was calculated. There was a good accordance between 3D TPS and MCNP5 simulation and differences in various distances were between 2.4% and 6.1%. There was a predictable accordance between MAGICA gel dosimetry and MCNP5 simulation and differences in various distances were between 5.7% and 7.4%. Moreover, there was an acceptable accordance between MAGICA gel dosimetry and MCNP5 data and differences in various distances were between 5.2% and 9.4%. Conclusion: The sources of differences in this comparison are divided to calculations variation and practical errors that was added in experimental dosimetry. The result of quality assurance of nasopharynx high dose rate brachytherapy is consistent with international standards.

  3. Inhalation of the BK(Ca-opener NS1619 attenuates right ventricular pressure and improves oxygenation in the rat monocrotaline model of pulmonary hypertension.

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    Marc Revermann

    Full Text Available BACKGROUND: Right heart failure is a fatal consequence of chronic pulmonary hypertension (PH. The development of PH is characterized by increased proliferation of vascular cells, in particular pulmonary artery smooth muscle cells (PASMCs and pulmonary artery endothelial cells. In the course of PH, an escalated right ventricular (RV afterload occurs, which leads to increased perioperative morbidity and mortality. BK(Ca channels are ubiquitously expressed in vascular smooth muscle cells and their opening induces cell membrane hyperpolarization followed by vasodilation. Moreover, BK activation induces anti-proliferative effects in a multitude of cell types. On this basis, we hypothesized that treatment with the nebulized BK channel opener NS1619 might be a therapy option for pulmonary hypertension and tested this in rats. METHODS: (1 Rats received monocrotaline injection for PH induction. Twenty-four days later, rats were anesthetized and NS1619 or the solvent was administered by inhalation. Systemic hemodynamic parameters, RV hemodynamic parameters, and blood gas analyses were measured before as well as 30 and 120 minutes after inhalation. (2 Rat PASMCs were stimulated with PDGF-BB in the presence and absence of NS1619. AKT, ERK1 and ERK2 activation were investigated by western blot analyses, and relative cell number was determined 48 hours after stimulation. RESULTS: Inhalation of a 12 µM and 100 µM NS1619 solution significantly reduced RV pressure without affecting systemic arterial pressure. Blood gas analyses demonstrated significantly reduced carbon dioxide and improved oxygenation in NS1619-treated animals pointing towards a considerable pulmonary shunt-reducing effect. In PASMC's, NS1619 (100 µM significantly attenuated PASMC proliferation by a pathway independent of AKT and ERK1/2 activation. CONCLUSION: NS1619 inhalation reduces RV pressure and improves oxygen supply and its application inhibits PASMC proliferation in vitro. Hence, BK

  4. Evaluation of time, attendance of medical staff, and resources during interstitial brachytherapy for prostate cancer. DEGRO-QUIRO trial

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    Tselis, N.; Zamboglou, N. [Sana Klinikum Offenbach, Department of Radiation Oncology, Offenbach am Main (Germany); Maurer, U. [St.-Antonius-Hospital, Strahlentherapie, Eschweiler (Germany); Popp, W. [Prime Networks AG, Basel (Switzerland); Sack, H. [University of Essen, Department of Radiation Oncology, Essen (Germany)


    The German Society of Radiation Oncology initiated a multicenter trial to evaluate core processes and subprocesses of radiotherapy by prospective evaluation of all important procedures in the most frequent malignancies treated by radiation therapy. The aim of this analysis was to assess the required resources for interstitial high-dose-rate (HDR) and low-dose-rate (LDR) prostate brachytherapy (BRT) based on actual time measurements regarding allocation of personnel and room occupation needed for specific procedures. Two radiotherapy centers (community hospital of Offenbach am Main and community hospital of Eschweiler) participated in this prospective study. Working time of the different occupational groups and room occupancies for the workflow of prostate BRT were recorded and methodically assessed during a 3-month period. For HDR and LDR BRT, a total of 560 and 92 measurements, respectively, were documented. The time needed for treatment preplanning was median 24 min for HDR (n=112 measurements) and 6 min for LDR BRT (n=21). Catheter implantation with intraoperative HDR real-time planning (n=112), postimplantation HDR treatment planning (n=112), and remotely controlled HDR afterloading irradiation (n=112) required median 25, 39, and 50 min, respectively. For LDR real-time planning (n=39) and LDR treatment postplanning (n=32), the assessed median duration was 91 and 11 min, respectively. Room occupancy and overall mean medical staff times were 194 and 910 min respectively, for HDR, and 113 and 371 min, respectively, for LDR BRT. In this prospective analysis, the resource requirements for the application of HDR and LDR BRT of prostate cancer were assessed methodically and are presented for first time. (orig.)

  5. HDR {sup 192}Ir source speed measurements using a high speed video camera

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    Fonseca, Gabriel P. [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000, Brazil and Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Viana, Rodrigo S. S.; Yoriyaz, Hélio [Instituto de Pesquisas Energéticas e Nucleares—IPEN-CNEN/SP, São Paulo 05508-000 (Brazil); Podesta, Mark [Department of Radiation Oncology (MAASTRO), GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Rubo, Rodrigo A.; Sales, Camila P. de [Hospital das Clínicas da Universidade de São Paulo—HC/FMUSP, São Paulo 05508-000 (Brazil); Reniers, Brigitte [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Research Group NuTeC, CMK, Hasselt University, Agoralaan Gebouw H, Diepenbeek B-3590 (Belgium); Verhaegen, Frank, E-mail: [Department of Radiation Oncology - MAASTRO, GROW School for Oncology and Developmental Biology, Maastricht University Medical Center, Maastricht 6201 BN (Netherlands); Medical Physics Unit, Department of Oncology, McGill University, Montréal, Québec H3G 1A4 (Canada)


    Purpose: The dose delivered with a HDR {sup 192}Ir afterloader can be separated into a dwell component, and a transit component resulting from the source movement. The transit component is directly dependent on the source speed profile and it is the goal of this study to measure accurate source speed profiles. Methods: A high speed video camera was used to record the movement of a {sup 192}Ir source (Nucletron, an Elekta company, Stockholm, Sweden) for interdwell distances of 0.25–5 cm with dwell times of 0.1, 1, and 2 s. Transit dose distributions were calculated using a Monte Carlo code simulating the source movement. Results: The source stops at each dwell position oscillating around the desired position for a duration up to (0.026 ± 0.005) s. The source speed profile shows variations between 0 and 81 cm/s with average speed of ∼33 cm/s for most of the interdwell distances. The source stops for up to (0.005 ± 0.001) s at nonprogrammed positions in between two programmed dwell positions. The dwell time correction applied by the manufacturer compensates the transit dose between the dwell positions leading to a maximum overdose of 41 mGy for the considered cases and assuming an air-kerma strength of 48 000 U. The transit dose component is not uniformly distributed leading to over and underdoses, which is within 1.4% for commonly prescribed doses (3–10 Gy). Conclusions: The source maintains its speed even for the short interdwell distances. Dose variations due to the transit dose component are much lower than the prescribed treatment doses for brachytherapy, although transit dose component should be evaluated individually for clinical cases.

  6. Evaluation of Physiological Control Systems for Rotary Left Ventricular Assist Devices: An In-Vitro Study. (United States)

    Pauls, Jo P; Stevens, Michael C; Bartnikowski, Nicole; Fraser, John F; Gregory, Shaun D; Tansley, Geoff


    Rotary left ventricular assist devices (LVADs) show weaker response to preload and greater response to afterload than the native heart. This may lead to ventricular suction or pulmonary congestion, which can be deleterious to the patient's recovery. A physiological control system which optimizes responsiveness of LVADs may reduce adverse events. This study compared eight physiological control systems for LVAD support against constant speed mode. Pulmonary (PVR) and systemic (SVR) vascular resistance changes, a passive postural change and exercise were simulated in a mock circulation loop to evaluate the controller's ability to prevent suction and congestion and to increase exercise capacity. Three active and one passive control systems prevented ventricular suction at high PVR (500 dyne s cm(-5)) and low SVR (600 dyne s cm(-5)) by decreasing LVAD speed (by 200-515 rpm) and by increasing LVAD inflow cannula resistance (up to 1000 dyne s cm(-5)) respectively. These controllers increased LVAD preload sensitivity (to 0.196-2.415 L min(-1) mmHg(-1)) compared to the other control systems and constant speed mode (0.039-0.069 L min(-1) mmHg(-1)). The same three active controllers increased pump speed (600-800 rpm) and thus LVAD flow by 4.5 L min(-1) during exercise which increased exercise capacity. Physiological control systems that prevent adverse events and/or increase exercise capacity may help improve LVAD patient conditions.


    Directory of Open Access Journals (Sweden)

    Vincenzo eBarrese


    Full Text Available The use of -blockers (BB in heart failure (HF has been considered a contradiction for many years. Considering HF simply as a state of inadequate systolic function, BB were contraindicated because of their negative effects on myocardial contractility. Nevertheless, evidence collected in the past years have suggested that additional mechanisms, such as compensatory neuro-humoral hyperactivation or inflammation, could participate in the pathogenesis of this complex disease. Indeed, chronic activation of the sympathetic nervous system, although initially compensating the reduced cardiac output from the failing heart, increases myocardial oxygen demand, ischemia and oxidative stress; moreover, high catecholamine levels induce peripheral vasoconstriction and increase both cardiac pre- and after-load, thus determining additional stress to the cardiac muscle (1. As a consequence of such a different view of the pathogenic mechanisms of HF, the efficacy of BB in the treatment of HF has been investigated in numerous clinical trials. Results from these trials highlighted BB as valid therapeutic tools in HF, providing rational basis for their inclusion in many HF treatment guidelines. However, controversy still exists about their use, in particular with regards to the selection of specific molecules, since BB differ in terms of adrenergic -receptors selectivity, adjunctive effects on -receptors, and effects on reactive oxygen species and inflammatory cytokines production. Further concerns about the heterogeneity in the response to , as well as the use in specific patients, are matter of debate among clinicians. In this review, we will recapitulate the pharmacological properties and the classification of BB, and the alteration of the adrenergic system occurring during HF that provide a rationale for their use; we will also focus on the possible molecular mechanisms, such as genetic polymorphisms, underlying the different efficacy of molecules

  8. The development and application of a radiofrequency (RF) interstitial hyperthermia system to prostate cancer

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    Uchida, Nobue; Kawaguchi, Atsuya; Moriyama, Masahiro; Kitagaki, Hajime; Urakami, Shinji; Igawa, Mikio [Shimane Medical Univ., Izumo (Japan); Kato, Hirokazu [Okayama Univ. (Japan). School of Medicine; Kasai, Toshifumi [Kyoto Coll. of Medical Technology, Sonobe (Japan)


    To heat a greater volume less invasively and more effectively, we developed a multi-channel RF interstitial hyperthermia system compatible with the high-dose rate Iridium-192 remote after-loading system (Ir-192 RALS). The system is composed of eight channel RF signal generators, which can be controlled individually. Each RF generator can be connected to an internal electrode, which was originally an Ir-192 RALS applicator; and a shared rectangular external electrode made of aluminum. By means of experiments using an agar phantom and an animal liver, we evaluated the heating characteristics, safety, and feasibility of this system. Subsequently, we applied trans-perineal radiofrequency (RF) interstitial hyperthermia and Ir-192 RALS for localized prostate cancer (PC). Under trans-rectal ultrasound guidance, 18 stainless applicators for Ir-192 RALS were inserted into the prostatic gland and seminal vesicles in an optimized pattern. Eight applicators were used as internal electrodes and were electrically insulated along the length of subdermal fat tissue using a vinyl catheter. The temperature inside the prostate and rectum was monitored continuously. Hyperthermia was performed following the first and fourth Ir-192 RALS (total of 24 Gy/4 fractions). Total doses of 46 Gy were also delivered by linear accelerator. There were no complications, such as infection, bleeding, fat necrosis, or burns. Histological examination after the treatment revealed cancer cell death and necrosis. MRI and CT images showed a well-demarcated, low-intensity area at the center of the prostate reflecting the necrotic area. Trans-perineal hyperthermoradiotherapy is a feasible and effective therapeutic alternative for the treatment of patients with localized PC. In addition, our system is compatible with the Ir-192 RALS, allowing for less-invasive interstitial hyperthermoradiotherapy by eliminating the trauma of needle re-insertion. (author)

  9. Benefit of warm water immersion on biventricular function in patients with chronic heart failure

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    Kardassis Dimitris


    Full Text Available Abstract Background Regular physical activity and exercise are well-known cardiovascular protective factors. Many elderly patients with heart failure find it difficult to exercise on land, and hydrotherapy (training in warm water could be a more appropriate form of exercise for such patients. However, concerns have been raised about its safety. The aim of this study was to investigate, with echocardiography and Doppler, the acute effect of warm water immersion (WWI and effect of 8 weeks of hydrotherapy on biventricular function, volumes and systemic vascular resistance. A secondary aim was to observe the effect of hydrotherapy on brain natriuretic peptide (BNP. Methods Eighteen patients [age 69 ± 8 years, left ventricular ejection fraction 31 ± 9%, peakVO2 14.6 ± 4.5 mL/kg/min] were examined with echocardiography on land and in warm water (34°C. Twelve of these patients completed 8 weeks of control period followed by 8 weeks of hydrotherapy twice weekly. Results During acute WWI, cardiac output increased from 3.1 ± 0.8 to 4.2 ± 0.9 L/min, LV tissue velocity time integral from 1.2 ± 0.4 to 1.7 ± 0.5 cm and right ventricular tissue velocity time integral from 1.6 ± 0.6 to 2.5 ± 0.8 cm (land vs WWI, p There was no change in the cardiovascular response or BNP after 8 weeks of hydrotherapy. Conclusion Hydrotherapy was well tolerated by all patients. The main observed cardiac effect during acute WWI was a reduction in heart rate, which, together with a decrease in afterload, resulted in increases in systolic and diastolic biventricular function. Although 8 weeks of hydrotherapy did not improve cardiac function, our data support the concept that exercise in warm water is an acceptable regime for patients with heart failure.

  10. Dysregulated renin-angiotensin-aldosterone system contributes to pulmonary arterial hypertension (United States)

    De Man, Frances; Tu, Ly; Handoko, Louis; Rain, Silvia; Ruiter, Gerrina; François, Charlène; Schalij, Ingrid; Dorfmüller, Peter; Simonneau, Gérald; Fadel, Elie; Perros, Frederic; Boonstra, Anco; Postmus, Piet; Van Der Velden, Jolanda; Vonk-Noordegraaf, Anton; Humbert, Marc; Eddahibi, Saadia; Guignabert, Christophe


    Rationale Patients with idiopathic pulmonary arterial hypertension (iPAH) often have a low cardiac output. To compensate, neurohormonal systems like renin-angiotensin-aldosterone system (RAAS) and sympathetic nervous system are upregulated but this may have long-term negative effects on the progression of iPAH. Objectives Assess systemic and pulmonary RAAS-activity in iPAH-patients and determine the efficacy of chronic RAAS-inhibition in experimental PAH. Measurements and Main Results We collected 79 blood samples from 58 iPAH-patients in the VU University Medical Center Amsterdam (between 2004–2010), to determine systemic RAAS-activity. We observed increased levels of renin, angiotensin (Ang) I and AngII, which was associated with disease progression (p<0.05) and mortality (p<0.05). To determine pulmonary RAAS-activity, lung specimens were obtained from iPAH-patients (during lung transplantation, n=13) and controls (during lobectomy or pneumonectomy for cancer, n=14). Local RAAS-activity in pulmonary arteries of iPAH-patients was increased, demonstrated by elevated ACE-activity in pulmonary endothelial cells and increased AngII type 1 (AT1) receptor expression and signaling. In addition, local RAAS- upregulation was associated with increased pulmonary artery smooth muscle cell proliferation via enhanced AT1-receptor signaling in iPAH-patients compared to controls. Finally, to determine the therapeutic potential of RAAS-activity, we assessed the chronic effects of an AT1-receptor antagonist (losartan) in the monocrotaline PAH-rat model (60 mg/kg). Losartan delayed disease progression, decreased RV afterload and pulmonary vascular remodeling and restored right ventricular-arterial coupling in PAH-rats. Conclusions Systemic and pulmonary RAAS-activities are increased in iPAH-patients and associated with increased pulmonary vascular remodeling. Chronic inhibition of RAAS by losartan is beneficial in experimental PAH. PMID:22859525

  11. Complex myograph allows the examination of complex muscle contractions for the assessment of muscle force, shortening, velocity, and work in vivo

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    Ruhschulte Hainer


    Full Text Available Abstract Background The devices used for in vivo examination of muscle contractions assess only pure force contractions and the so-called isokinetic contractions. In isokinetic experiments, the extremity and its muscle are artificially moved with constant velocity by the measuring device, while a tetanic contraction is induced in the muscle, either by electrical stimulation or by maximal voluntary activation. With these systems, experiments cannot be performed at pre-defined, constant muscle length, single contractions cannot be evaluated individually and the separate examination of the isometric and the isotonic components of single contractions is not possible. Methods The myograph presented in our study has two newly developed technical units, i.e. a. a counterforce unit which can load the muscle with an adjustable, but constant force and b. a length-adjusting unit which allows for both the stretching and the contraction length to be infinitely adjustable independently of one another. The two units support the examination of complex types of contraction and store the counterforce and length-adjusting settings, so that these conditions may be accurately reapplied in later sessions. Results The measurement examples presented show that the muscle can be brought to every possible pre-stretching length and that single isotonic or complex isometric-isotonic contractions may be performed at every length. The applied forces act during different phases of contraction, resulting into different pre- and after-loads that can be kept constant – uninfluenced by the contraction. Maximal values for force, shortening, velocity and work may be obtained for individual muscles. This offers the possibility to obtain information on the muscle status and to monitor its changes under non-invasive measurement conditions. Conclusion With the Complex Myograph, the whole spectrum of a muscle's mechanical characteristics may be assessed.

  12. The effect of aortic coarctation surgical repair on QTc and JTc dispersion in severe aortic coarctation newborns: a short-term follow-up study. (United States)

    Nigro, G; Russo, V; Rago, A; Papa, A A; Cioppa, N D; Scarpati, C; Palladino, T; Corcione, A; Sarubbi, B; Caianiello, G; Russo, M G


    Sudden death is a possible occurrence for newborns younger than 1 year with severe aortic coarctation (CoA) before surgical correction. In our previous study, we showed a significant increase of QTc-D and JTc-D in newborns with isolated severe aortic coarctation, electrocardiographic parameters that clinical and experimental studies have suggested could reflect the physiological variability of regional and ventricular repolarization and could provide a substrate for life-threatening ventricular arrhythmias. The aim of the current study was to evaluate the effect of surgical repair of CoA on QTc-d, JTc-d in severe aortic coarctation newborns with no associated congenital cardiac malformations. The study included 30 newborns (18M; 70+/-12 h old) affected by severe congenital aortic coarctation, without associated cardiac malformations. All newborns underwent to classic extended end-to-end repair. Echocardiographic and electrocardiographic measurements were performed in each patient 24 h before and 24 h after the interventional procedure and at the end of the follow-up period, 1 month after the surgical correction. All patients at baseline, 24 h and one month after CoA surgical repair did not significantly differ in terms of heart rate, weight, height, and echocardiographic parameters. There were no statistically significant differences in QTc-D (111.7+/-47.4 vs 111.9+/-63.8 ms vs 108.5+/-55.4 ms; P=0.4) and JTc-D (98.1+/-41.3 vs 111.4+/-47.5 vs 105.1+/-33.4 ms; P=0.3) before, 24 h and 1 month after CoA surgical correction. In conclusions, our study did not show a statistically significant decrease in QTc-D and JTc-D, suggesting the hypothesis that the acute left ventricular afterload reduction, related to successful CoA surgical correction, may not reduce the ventricular electrical instability in the short-term follow-up.

  13. Dwell time modulation restrictions do not necessarily improve treatment plan quality for prostate HDR brachytherapy (United States)

    Balvert, Marleen; Gorissen, Bram L.; den Hertog, Dick; Hoffmann, Aswin L.


    Inverse planning algorithms for dwell time optimisation in interstitial high-dose-rate (HDR) brachytherapy may produce solutions with large dwell time variations within catheters, which may result in undesirable selective high-dose subvolumes. Extending the dwell time optimisation model with a dwell time modulation restriction (DTMR) that limits dwell time differences between neighboring dwell positions has been suggested to eliminate this problem. DTMRs may additionally reduce the sensitivity for uncertainties in dwell positions that inevitably result from catheter reconstruction errors and afterloader source positioning inaccuracies. This study quantifies the reduction of high-dose subvolumes and the robustness against these uncertainties by applying a DTMR to template-based prostate HDR brachytherapy implants. Three different DTMRs were consecutively applied to a linear dose-based penalty model (LD) and a dose-volume based model (LDV), both obtained from literature. The models were solved with DTMR levels ranging from no restriction to uniform dwell times within catheters in discrete steps. Uncertainties were simulated on clinical cases using in-house developed software, and dose-volume metrics were calculated in each simulation. For the assessment of high-dose subvolumes, the dose homogeneity index (DHI) and the contiguous dose volume histogram were analysed. Robustness was measured by the improvement of the lowest D90% of the planning target volume (PTV) observed in the simulations. For (LD), a DTMR yields an increase in DHI of approximately 30% and reduces the size of the largest high-dose volume by 2-5 cc. However, this comes at a cost of a reduction in D90% of the PTV of 10%, which often implies that it drops below the desired minimum of 100%. For (LDV), none of the DTMRs were able to improve high-dose volume measures. DTMRs were not capable of improving robustness of PTV D90% against uncertainty in dwell positions for both models.

  14. Captopril-induced reduction of regurgitation fraction in aortic insufficiency

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    Kropp, J.; Reske, S.N.; Biersack, H.J.; Heck, I.; Mattern, H.; Winkler, C.


    Stimulated Renin-Angiotensin System (RAS) in aortic insufficiency (AI) leads to increased afterload and consequently to augmented aortic regurgitation (R). Therefore Captopril (C) mediated RAS-inhibition should diminish systemic vascular resistance and thus reduce R. In 9 patients (pts) with pure severe AI regurgitation fraction (RF) and left ventricular ejection fraction (LVEF) were determined before and 1 hr after i.v. injection of 25 mg C by gated radionuclide ventriculographie (RNV), using red blood cells labeled in vivo with 15 mCi Tc-99m. Enddiastolic and endsystolid frames were derived from the left ventricular volume curve. ROI's were selected over both ventricles. Ventricular boundaries were defined by a fourier phase image overlay. RF was calculated by the background corrected count rate ratio of left and right ventricular ROI. Arterial blood pressure (BP), heart rate (HR), plasma levels of angiotensin I, II (A1,A2), and the activity of angiotensin converting enzyme (ACE) were determined before and 1 hr after C-injection. Before C-medication mean RF was 54% (range 34% - 67%), after C mean RF decreased to 37% (17% - 59% range, rho<.05). Mean LVEF increased not significantly from 60% (range 51%-70%) to 66% (range 56% - 77%, rho>0.55). C did not significantly change HR or BP (HR: rho>0.9, BP: rho>0.6). A2 and ACE activity decreased to 40% and 50% of control values (rho<.01), respectively. A1 increased excessively. The authors conclude that the inhibition of ACE reduces significantly aortic regurgitation in patients with A1 and has thus a beneficial effect on left ventricular performance.

  15. [Edge effect and late thrombosis -- inevitable complications of vascular brachytherapy?]. (United States)

    Schiele, T M; Staber, L; Kantlehner, R; Pöllinger, B; Dühmke, E; Theisen, K; Klauss, V


    Restenosis is the limiting entity after percutaneous coronary angioplasty. Vascular brachytherapy for the treatment of in-stent restenosis has been shown to reduce the repeat restenosis rate and the incidence of major adverse events in several randomized trials. Besides the beneficial effects, brachytherapy yielded some unwanted side effects. The development of new stenoses at the edges of the target lesion treated with radiation is termed edge effect. It occurs after afterloading brachytherapy as well as after implantation of radioactive stents. It is characterized by extensive intimal hyperplasia and negative remodeling. As contributing factors the axial dose fall-off, inherent to all radioactive sources, and the application of vessel wall trauma by angioplasty have been identified. The combination of both factors, by insufficient overlap of the radiation length over the injured vessel segment, has been referred to as geographic miss. It has been shown to be associated with a very high incidence of the edge effect. Avoidance of geographic miss is strongly recommended in vascular brachytherapy procedures. Late thrombosis after vascular brachytherapy is of multifactorial origin. It comprises platelet recruitment, fibrin deposition, disturbed vasomotion, non-healing dissection and stent malapposition predisposing to turbulent blood flow. The strongest predictors for late thrombosis are premature discontinuation of antiplatelet therapy and implantation of new stents during the brachytherapy procedure. With a consequent and prolonged antiplatelet therapy, the incidence of late thrombosis has been reduced to placebo levels. Edge effect and late thrombosis represent unwanted side effects of vascular brachytherapy. By means of a thorough treatment planning and prolonged antiplatelet therapy their incidences can be largely reduced. With regard to the very favorable net effect, they do not constitute relevant limitations of vascular brachytherapy.

  16. Microwave hyperthermia radiosensitized iridium-192 for recurrent brain malignancy. (United States)

    Borok, T L; Winter, A; Laing, J; Paglione, R; Sterzer, F; Sinclair, I; Plafker, J


    Twenty-one patients whose solitary detectable biopsy proven recurrent brain malignancies produced Central Nervous System (CNS) symptoms warranting further intervention received 60-minute 43 degrees C (180 degree-minute) interstitial 2450 MHz microwave hyperthermia fractions. All received brain teletherapy prior to recurrence. The first 15 received no brachytherapy and served as a toxicity pilot. All 15 enjoyed neurologic improvement, 12 symptomatic improvement, and 12 objective response as mass reduction and/or tumor necrosis. The next 6 patients were selected with more favorable Karnofsky performance status, no known active malignancy elsewhere, and received afterloading Ir-192 interstitial implantation juxtaposed to radiosensitizing hyperthermia. Volume dose varied from 1000 to 2245 rad, and dose rate from 40 to 100 rad/hr. Dose selected varied as a function of pre-recurrence teletherapy dose, general condition, histologic type, and volume. Neurosurgical debulking, if technically indicated through no additional aperture or trauma, was permitted if consistent with preservation of neurological function. Six enjoyed neurologic improvement, symptom reduction, and objective tumor response; three remain alive, and one experienced transient improvement. Complications, histologic subtypes, autopsy findings, stereotactic approach, thermal monitoring methods and CT follow-up of objective response are presented along with computer dosimetry and isotherm chart. Our microtraumatic universal catheter technique for CT guided stereotactic biopsy, aspiration, decompression, thermal sensory loop, thermalization antennae, and brachytherapy without multiple trauma nor changing catheters is stressed. The rationale for combined modes peculiar to the CNS will be outlined.2+ Proposal for incorporating controlled-release ARA-C chemotherapy polymer micro-rods into the interstitial format will be offered. The preceeding is an FDA-approved controlled clinical trial.(ABSTRACT TRUNCATED AT

  17. Dosimetry audit on the accuracy of 192Ir brachytherapy source strength determinations in Sweden

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    Carlsson Tedgren, Aasa


    The absorbed dose delivered to the patient in brachytherapy is directly proportional to the source strength in terms of the reference air-kerma rate (RAKR). Verification of this quantity by the hospitals is widely recognized as an important part of a quality assurance program. An external audit was performed on behalf of the Secondary Standard Dosimetry Laboratory at the Swedish Radiation Protection Authority (SSI). The aim was to investigate how accurately the source-strength in 192Ir brachytherapy is determined at Swedish hospitals. The SSI reference well-type ion chamber and calibrated equipment were used to measure the RAKR of an 192Ir source in each of the 14 Swedish afterloading units. Comparisons with values determined by vendors and hospitals were made. Agreement in values of RAKR as determined by SSI, hospitals and vendors were in all cases within the +-3% uncertainty (at a coverage factor of k=2), typically guaranteed by the vendors. The good agreement reflects the robustness and easy handling of well-type chambers designed for brachytherapy in use by all Swedish hospitals. The 192Ir calibration service planned at SSI will solve the hospitals current problem with recalibration of equipment. SSI can also advise hospitals to follow the IAEA recommendations for measurement techniques and maintenance of equipment. It is worthwhile for the hospitals to establish their own ratio (or deviation) with the vendor and follow it as function of time. Such a mean-ratio embeds systematic differences of various origins and have a lower uncertainty than has the RAKR alone, making it useful for early detection of problems with equipment or routines. SSI could also define requirements for the agreement between source strengths as determined by hospitals and vendors and couple this to an action plan, dependent on level of disagreement, and some kind of reporting to SSI

  18. Abnormal pulmonary artery stiffness in pulmonary arterial hypertension: in vivo study with intravascular ultrasound.

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    Edmund M T Lau

    Full Text Available BACKGROUND: There is increasing recognition that pulmonary artery stiffness is an important determinant of right ventricular (RV afterload in pulmonary arterial hypertension (PAH. We used intravascular ultrasound (IVUS to evaluate the mechanical properties of the elastic pulmonary arteries (PA in subjects with PAH, and assessed the effects of PAH-specific therapy on indices of arterial stiffness. METHOD: Using IVUS and simultaneous right heart catheterisation, 20 pulmonary segments in 8 PAH subjects and 12 pulmonary segments in 8 controls were studied to determine their compliance, distensibility, elastic modulus and stiffness index β. PAH subjects underwent repeat IVUS examinations after 6-months of bosentan therapy. RESULTS: AT BASELINE, PAH SUBJECTS DEMONSTRATED GREATER STIFFNESS IN ALL MEASURED INDICES COMPARED TO CONTROLS: compliance (1.50±0.11×10(-2 mm(2/mmHg vs 4.49±0.43×10(-2 mm(2/mmHg, p<0.0001, distensibility (0.32±0.03%/mmHg vs 1.18±0.13%/mmHg, p<0.0001, elastic modulus (720±64 mmHg vs 198±19 mmHg, p<0.0001, and stiffness index β (15.0±1.4 vs 11.0±0.7, p = 0.046. Strong inverse exponential associations existed between mean pulmonary artery pressure and compliance (r(2 = 0.82, p<0.0001, and also between mean PAP and distensibility (r(2 = 0.79, p = 0.002. Bosentan therapy, for 6-months, was not associated with any significant changes in all indices of PA stiffness. CONCLUSION: Increased stiffness occurs in the proximal elastic PA in patients with PAH and contributes to the pathogenesis RV failure. Bosentan therapy may not be effective at improving PA stiffness.

  19. Diagnosis and management of cardiogenic pulmonary edema. (United States)

    Alwi, Idrus


    Acute cardiogenic pulmonary edema (ACPE) is a common cardiogenic emergency with a quite high in-hospital mortality rate. ACPE is defined as pulmonary edema with increased secondary hydrostatic capillary pressure due to elevated pulmonary venous pressure. Increased hydrostatic pressure may result from various causes including excessive administration of intravascular volume, obstruction of pulmonary venous outflow or secondary left ventricular failure due to left ventricular systolic or diastolic dysfunction. ACPE must be distinguished from pulmonary edema associated with injury of alveolar capillary membrane caused by various etiologies, i.e. direct pulmonary injury such as pneumonia and indirect pulmonary injury such as sepsis. Numerous clinical manifestations may differentiate ACPE and Non-ACPE. ACPE usually presents with a history of acute cardiac catastrophe. Physical examination reveals a low-flow state, S3 gallop, jugular venous distention and fine crepitant rales with auscultation. The diagnosis of pulmonary edema is made based on symptoms and clinical signs are found through history taking, physical examination, ECG, chest X-ray, echocardiography and laboratory tests including blood gas analysis and specific biomarkers. Medical treatment of ACPE has 3 main objectives, i.e.: (1) reduced venous return (preload reduction); (2) reduced resistance of systemic vascular (afterload reduction); and (3) inotropic support in some cases. Treatment that can be administered includes: vasodilator when there is normal or high BP, diuretics when there is volume overload or fluid retention, and inotropic drugs when there is hypotension or signs of organ hypoperfusion. Intubation and mechanical ventilation may be necessary to achieve adequate oxygenation.

  20. Contralateral breast dose from partial breast brachytherapy. (United States)

    Robinson, R Cole; Nelson, Christopher L; Bloom, Elizabeth S; Kisling, Kelly D; Mason, Bryan E; Fisher, Gary D; Kirsner, Steven M


    The purpose of this study was to determine the dose to the contralateral breast during accelerated partial breast irradiation (APBI) and to compare it to external beam-published values. Thermoluminescent dosimeter (TLD) packets were used to measure the dose to the most medial aspect of the contralateral breast during APBI simulation, daily quality assurance (QA), and treatment. All patients in this study were treated with a single-entry, multicatheter device for 10 fractions to a total dose of 34 Gy. A mark was placed on the patient's skin on the medial aspect of the opposite breast. Three TLD packets were taped to this mark during the pretreatment simulation. Simulations consisted of an AP and Lateral scout and a limited axial scan encompassing the lumpectomy cavity (miniscan), if rotation was a concern. After the simulation the TLD packets were removed and the patients were moved to the high-dose-rate (HDR) vault where three new TLD packets were taped onto the patients at the skin mark. Treatment was administered with a Nucletron HDR afterloader using Iridium-192 as the treatment source. Post-treatment, TLDs were read (along with the simulation and QA TLD and a set of standards exposed to a known dose of 6 MV photons). Measurements indicate an average total dose to the contralateral breast of 70 cGy for outer quadrant implants and 181 cGy for inner quadrant implants. Compared to external beam breast tangents, these results point to less dose being delivered to the contralateral breast when using APBI.

  1. Surgical removal of right-to-left cardiac shunt in the American alligator (Alligator mississippiensis) causes ventricular enlargement but does not alter apnoea or metabolism during diving (United States)

    Eme, John; Gwalthney, June; Blank, Jason M.; Owerkowicz, Tomasz; Barron, Gildardo; Hicks, James W.


    SUMMARY Crocodilians have complete anatomical separation between the ventricles, similar to birds and mammals, but retain the dual aortic arch system found in all non-avian reptiles. This cardiac anatomy allows surgical modification that prevents right-to-left (R–L) cardiac shunt. A R–L shunt is a bypass of the pulmonary circulation and recirculation of oxygen-poor blood back to the systemic circulation and has often been observed during the frequent apnoeic periods of non-avian reptiles, particularly during diving in aquatic species. We eliminated R–L shunt in American alligators (Alligator mississippiensis) by surgically occluding the left aorta (LAo; arising from right ventricle) upstream and downstream of the foramen of Panizza (FoP), and we tested the hypotheses that this removal of R–L shunt would cause afterload-induced cardiac remodelling and adversely affect diving performance. Occlusion of the LAo both upstream and downstream of the FoP for ∼21 months caused a doubling of RV pressure and significant ventricular enlargement (average ∼65%) compared with age-matched, sham-operated animals. In a separate group of recovered, surgically altered alligators allowed to dive freely in a dive chamber at 23°C, occlusion of the LAo did not alter oxygen consumption or voluntary apnoeic periods relative to sham animals. While surgical removal of R–L shunt causes considerable changes in cardiac morphology similar to aortic banding in mammals, its removal does not affect the respiratory pattern or metabolism of alligators. It appears probable that the low metabolic rate of reptiles, rather than pulmonary circulatory bypass, allows for normal aerobic dives. PMID:19837897

  2. Astaxanthin vs placebo on arterial stiffness, oxidative stress and inflammation in renal transplant patients (Xanthin: a randomised controlled trial

    Directory of Open Access Journals (Sweden)

    Robertson Iain K


    Full Text Available Abstract Background There is evidence that renal transplant recipients have accelerated atherosclerosis manifest by increased cardiovascular morbidity and mortality. The high incidence of atherosclerosis is, in part, related to increased arterial stiffness, vascular dysfunction, elevated oxidative stress and inflammation associated with immunosuppressive therapy. The dietary supplement astaxanthin has shown promise as an antioxidant and anti-inflammatory therapeutic agent in cardiovascular disease. The aim of this trial is to investigate the effects of astaxanthin supplementation on arterial stiffness, oxidative stress and inflammation in renal transplant patients. Method and Design This is a randomised, placebo controlled clinical trial. A total of 66 renal transplant recipients will be enrolled and allocated to receive either 12 mg/day of astaxanthin or an identical placebo for one-year. Patients will be stratified into four groups according to the type of immunosuppressant therapy they receive: 1 cyclosporine, 2 sirolimus, 3 tacrolimus or 4 prednisolone+/-azathioprine, mycophenolate mofetil or mycophenolate sodium. Primary outcome measures will be changes in 1 arterial stiffness measured by aortic pulse wave velocity (PWV, 2 oxidative stress assessed by plasma isoprostanes and 3 inflammation by plasma pentraxin 3. Secondary outcomes will include changes in vascular function assessed using the brachial artery reactivity (BAR technique, carotid artery intimal medial thickness (CIMT, augmentation index (AIx, left ventricular afterload and additional measures of oxidative stress and inflammation. Patients will undergo these measures at baseline, six and 12 months. Discussion The results of this study will help determine the efficacy of astaxanthin on vascular structure, oxidative stress and inflammation in renal transplant patients. This may lead to a larger intervention trial assessing cardiovascular morbidity and mortality. Trial Registration

  3. Intrauterine endotoxin-induced impairs pulmonary vascular function and right ventricular performance in infant rats and improvement with early vitamin D therapy. (United States)

    Mandell, Erica; Powers, Kyle N; Harral, Julie W; Seedorf, Gregory J; Hunter, Kendall S; Abman, Steven H; Dodson, R Blair


    High pulmonary vascular resistance (PVR), proximal pulmonary artery (PA) impedance, and right ventricular (RV) afterload due to remodeling contribute to the pathogenesis and severity of pulmonary hypertension (PH). Intra-amniotic exposure to endotoxin (ETX) causes sustained PH and high mortality in rat pups at birth, which are associated with impaired vascular growth and RV hypertrophy in survivors. Treatment of ETX-exposed pups with antenatal vitamin D (vit D) improves survival and lung growth, but the effects of ETX exposure on RV-PA coupling in the neonatal lung are unknown. We hypothesized that intrauterine ETX impairs RV-PA coupling through sustained abnormalities of PA stiffening and RV performance that are attenuated with vit D therapy. Fetal rats were exposed to intra-amniotic injections of ETX, ETX+vit D, or saline at 20 days gestation (term = 22 days). At postnatal day 14, pups had pressure-volume measurements of the RV and isolated proximal PA, respectively. Lung homogenates were assayed for extracellular matrix (ECM) composition by Western blot. We found that ETX lungs contain decreased α-elastin, lysyl oxidase, collagen I, and collagen III proteins (P < 0.05) compared control and ETX+vit D lungs. ETX-exposed animals have increased RV mechanical stroke work (P < 0.05 vs. control and ETX+vit D) and elastic potential energy (P < 0.05 vs. control and ETX+vit D). Mechanical stiffness and ECM remodeling are increased in the PA (P < 0.05 vs. control and ETX+vit D). We conclude that intrauterine exposure of fetal rats to ETX during late gestation causes persistent impairment of RV-PA coupling throughout infancy that can be prevented with early vit D treatment.

  4. Gene expression profiles of vascular smooth muscle show differential expression of mitogen-activated protein kinase pathways during captopril therapy of heart failure. (United States)

    Chen, Frank C; Brozovich, Frank V


    Congestive heart failure (CHF) is characterized by increased vascular tone and an impairment in nitric-oxide-mediated vasodilatation. We have demonstrated that the blunted response to nitric oxide is due, in part, to a reduction in the leucine-zipper-positive isoform of the myosin-targeting subunit (MYPT1) of myosin light-chain phosphatase. Additionally, we have shown that angiotensin-converting enzyme inhibition, but not afterload reduction with prazosin, preserves leucine-zipper-positive MYPT1 isoform expression in vascular smooth muscle cells and normalizes the sensitivity to cGMP-mediated vasodilatation. We therefore hypothesized that in CHF, growth regulators and cytokines downstream of the angiotensin II receptor are involved in modulating gene expression in vascular tissue. Rats were divided into control and captopril-treated groups following left coronary artery ligation. Gene expression profiles in the aorta and portal vein at baseline and 2 and 4 weeks after myocardial infarction (MI) were analyzed using microarray technology and quantitative real-time PCR. After MI, microarray analysis revealed differential mRNA expression of 21 genes in the aorta of captopril-treated rats 2 and 4 weeks after surgery when compared to gene expression profiles at baseline and without captopril therapy. Real-time PCR demonstrated that captopril suppressed the expression of protein kinases in the angiotensin-II-mediated mitogen-activated protein kinase signaling pathway, including Taok1 and Raf1. These data suggest that in CHF, captopril therapy modulates gene expression in vascular smooth muscle, and some of the beneficial effects of ACE inhibition may be due to differential gene expression in the vasculature.

  5. Abnormal splicing in the N-terminal variable region of cardiac troponin T impairs systolic function of the heart with preserved Frank-Starling compensation. (United States)

    Feng, Han-Zhong; Chen, Guozhen; Nan, Changlong; Huang, Xupei; Jin, Jian-Ping


    Abnormal splice-out of the exon 7-encoded segment in the N-terminal variable region of cardiac troponin T (cTnT-ΔE7) was found in turkeys and, together with the inclusion of embryonic exon (eTnT), in adult dogs with a correlation with dilated cardiomyopathy. Overexpression of these cTnT variants in transgenic mouse hearts significantly decreased cardiac function. To further investigate the functional effect of cTnT-ΔE7 or ΔE7+eTnT in vivo under systemic regulation, echocardiography was carried out in single and double-transgenic mice. No atrial enlargement, ventricular hypertrophy or dilation was detected in the hearts of 2-month-old cTnT-ΔE7 and ΔE7+eTnT mice in comparison to wild-type controls, indicating a compensated state. However, left ventricular fractional shortening and ejection fraction were decreased in ΔE7 and ΔE7+eTnT mice, and the response to isoproterenol was lower in ΔE7+eTnT mice. Left ventricular outflow tract velocity and gradient were decreased in the transgenic mouse hearts, indicating decreased systolic function. Ex vivo working heart function showed that high afterload or low preload resulted in more severe decreases in the systolic function and energetic efficiency of cTnT-ΔE7 and ΔE7+eTnT hearts. On the other hand, increases in preload demonstrated preserved Frank-Starling responses and minimized the loss of cardiac function and efficiency. The data demonstrate that the N-terminal variable region of cardiac TnT regulates systolic function of the heart.

  6. The immune system and hypertension. (United States)

    Singh, Madhu V; Chapleau, Mark W; Harwani, Sailesh C; Abboud, Francois M


    A powerful interaction between the autonomic and the immune systems plays a prominent role in the initiation and maintenance of hypertension and significantly contributes to cardiovascular pathology, end-organ damage and mortality. Studies have shown consistent association between hypertension, proinflammatory cytokines and the cells of the innate and adaptive immune systems. The sympathetic nervous system, a major determinant of hypertension, innervates the bone marrow, spleen and peripheral lymphatic system and is proinflammatory, whereas the parasympathetic nerve activity dampens the inflammatory response through α7-nicotinic acetylcholine receptors. The neuro-immune synapse is bidirectional as cytokines may enhance the sympathetic activity through their central nervous system action that in turn increases the mobilization, migration and infiltration of immune cells in the end organs. Kidneys may be infiltrated by immune cells and mesangial cells that may originate in the bone marrow and release inflammatory cytokines that cause renal damage. Hypertension is also accompanied by infiltration of the adventitia and perivascular adipose tissue by inflammatory immune cells including macrophages. Increased cytokine production induces myogenic and structural changes in the resistance vessels, causing elevated blood pressure. Cardiac hypertrophy in hypertension may result from the mechanical afterload and the inflammatory response to resident or migratory immune cells. Toll-like receptors on innate immune cells function as sterile injury detectors and initiate the inflammatory pathway. Finally, abnormalities of innate immune cells and the molecular determinants of their activation that include toll-like receptor, adrenergic, cholinergic and AT1 receptors can define the severity of inflammation in hypertension. These receptors are putative therapeutic targets.

  7. Development of a compact wearable pneumatic drive unit for a ventricular assist device. (United States)

    Homma, Akihiko; Taenaka, Yoshiyuki; Tatsumi, Eisuke; Akagawa, Eiki; Lee, Hwansung; Nishinaka, Tomohiro; Takewa, Yoshiaki; Mizuno, Toshihide; Tsukiya, Tomonori; Kakuta, Yukihide; Katagiri, Nobumasa; Shimosaki, Isao; Hamada, Shigeru; Mukaibayashi, Hiroshi; Iwaoka, Wataru


    The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.

  8. Cardiac energetics: sense and nonsense. (United States)

    Gibbs, Colin L


    1. The background to current ideas in cardiac energetics is outlined and, in the genomic era, the need is stressed for detailed knowledge of mouse heart mechanics and energetics. 2. The mouse heart is clearly different to the rat in terms of its excitation-contraction (EC) coupling and the common assumption that heart rate difference between mice and humans will account for the eightfold difference in myocardial oxygen consumption is wrong, because the energy per beat of the mouse heart is approximately one-third that of the human heart. 3. In vivo evidence suggests that there may well be an eightfold species difference in the non-beating metabolism of mice and human hearts. It is speculated that the magnitude of basal metabolism in the heart is regulatable and that, in the absence of perfusion, it falls to approximately one-quarter of its in vivo rate and that in clinical conditions, such as hibernation, it probably decreases; its magnitude may be controlled by the endothelium. 4. The active energy balance sheet is briefly discussed and it is suggested that the activation heat accounts for 20-25% of the active energy per beat and cross-bridge turnover accounts for the balance. It is argued that force, not shortening, is the major determinant of cardiac energy usage. 5. The outcome of recent cardiac modelling with variants of the Huxley and Hill/Eisenberg models is described. It has been necessary to invoke 'loose coupling' to replicate the low cardiac energy flux measured at low afterloads (medium to high velocities of shortening). 6. Lastly, some of the unexplained or 'nonsense' energetic data are outlined and eight unsolved problems in cardiac energetics are discussed.

  9. Chemoradiation in cervical cancer with cisplatin and high-dose rate brachytherapy combined with external beam radiotherapy. Results of a phase-II study

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, H.G.; Laban, C.; Puschmann, D.; Koelbl, H. [Dept. of Gynecology, Martin-Luther Univ. Halle-Wittenberg (Germany); Kuhnt, T.; Pigorsch, S.; Dunst, J.; Haensgen, G. [Dept. of Radiotherapy, Martin-Luther Univ. Halle-Wittenberg (Germany)


    chemoradiation with cisplatin 40 mg/m{sup 2} weekly x 6 using HDR brachytherapy represents a promising treatment of cervical cancer with an acceptable toxicity. (orig.) [German] Hintergrund: 1999 zeigten fuenf randomisierte Studien, dass die simultane Radiochemotherapie mit Cisplatin und einer Low-Dose-Rate-Brachytherapie fuer Patientinnen mit einem lokal fortgeschrittenen Zervixkarzinom und in der adjuventen Hochrisikosituation einen Ueberlebensvorteil bringt. Wir untersuchten die Sicherheit und Effektivitaet der simultanen Radiochemotherapie mit Cisplatin und High-Dose-Rate-Brachytherapie bei diesen Patientinnen. Patientinnen und Methode: 27 Patientinnen wurden in unserer Phase-II-Studie eingeschlossen: 13 mit lokal fortgeschrittenen Zervixkarzinomen (Gruppe A) und 14 adjuvante Hochrisikopatientinnen (Gruppe B). Die primaer radiochemotherapierten Faelle erhielten 25 Fraktionen einer perktuanen Hochvolttherapie des Beckens (1,8 Gy pro Fraktion/Einbringen eines Mittelblocks nach elf Fraktionen). Die Brachytherapie wurde bei den FIGO-Stadien IIB-IIIB nach dem High-Dose-Rate-Afterloading-Prinzip mit 7 Gy pro Fraktion in Punkt A (Gesamtdosis 35 Gy) appliziert. Die Gesamtdosis der kombinierten Therapie war 70 Gy in Punkt A und 52-54 Gy in Punkt B. Bei den FIGO-Stadien IVA erfolgte keine Brachyhtherapie. Bei der adjuvanten Strahlentherapie wurde die perkutane Hochvolttherapie des Beckens mit Fraktionen von 1,8 Gy bis zu einer Gesamtdosis von 50,4 Gy appliziert. Die High-Dose-Rate-Afterloading-Brachytherapie mit zwei Fraktionen von 5 Gy erfolgte nur bei Patientinnen, bei denen sich im Operationspraeparat tumorbefallene Resektionsraender oder ein Befall der Scheide fanden. Das Chemotherapieregime mit 6 woechentlichen Gaben von 40 mg/m{sup 2} Cisplatin entsprach dem der Studien 120 und 123 der GOG. Ergebnisse: 18 von 27 Patientinnen (66,7%) erhielten alle sechs Cisplatingaben. Eine Unterbrechung der Strahlentherapie aufgrund von Nebenwirkungen war in keinem Fall erforderlich. Die G3

  10. [Alternative surgical options to heart transplantation]. (United States)

    Dreyfus, G


    Cardiac transplantation is the treatment of reference for refractory cardiac failure but the limited number of donors, the complications inherent to transplantation and the relative and absolute contra-indications has made it necessary to find alternative surgical solutions. The detection of myocardial viability by Thallium scintigraphy, Dobutamine echocardiography and/or position emission tomography in coronary disease, allows identification of zones which are capable of recovering contractile function after revascularisation. The authors report the results of a series of 91 operated patients with a 10 year follow-up having a 72% 5 year actuarial survival and improved ejection fraction. The other alternative which may improve symptoms and prognosis in patients with severe ischaemic heart disease with left ventricular dysfunction is apical remodelling or Dor's procedure. The results of a haemodynamic study at 1 year of 171 patients clearly show a functional improvement and an increase of the ejection fraction. The advantage of this method is that it can be used in patients with dyskinetic and akinetic plaques resulting from antero-septo-apical infarction. Finally, even if mitral regurgitation is relatively uncommon in chronic ischaemic heart disease, a simple procedure (annuloplasty) is often sufficient to correct the mitral regurgitation and reduce the afterload of a failing ventricle. On the other hand, in dilated cardiomyopathy, two new options have been developed; one, suggested by Steven Bolling, proposes simple mitral annuloplasty whatever the underlying cause (primary or ischaemic cardiomyopathy) with symptomatic improvement and better haemodynamics in terms of increased cardiac output and oxygen consumption on exercise and an actuarial survival much higher than that of cardiac transplantation at one and at two years. The most recent innovation is the Batista procedure which is a method of ventricular reduction associated with correction of mitral

  11. Non-invasive technology that improves cardiac function after experimental myocardial infarction: Whole Body Periodic Acceleration (pGz.

    Directory of Open Access Journals (Sweden)

    Arkady Uryash

    Full Text Available Myocardial infarction (MI may produce significant inflammatory changes and adverse ventricular remodeling leading to heart failure and premature death. Pharmacologic, stem cell transplantation, and exercise have not halted the inexorable rise in the prevalence and great economic costs of heart failure despite extensive investigations of such treatments. New therapeutic modalities are needed. Whole Body Periodic Acceleration (pGz is a non-invasive technology that increases pulsatile shear stress to the endothelium thereby producing several beneficial cardiovascular effects as demonstrated in animal models, normal humans and patients with heart disease. pGz upregulates endothelial derived nitric oxide synthase (eNOS and its phosphorylation (p-eNOS to improve myocardial function in models of myocardial stunning and preconditioning. Here we test whether pGz applied chronically after focal myocardial infarction in rats improves functional outcomes from MI. Focal MI was produced by left coronary artery ligation. One day after ligation animals were randomized to receive daily treatments of pGz for four weeks (MI-pGz or serve as controls (MI-CONT, with an additional group as non-infarction controls (Sham. Echocardiograms and invasive pressure volume loop analysis were carried out. Infarct transmurality, myocardial fibrosis, and markers of inflammatory and anti-inflammatory cytokines were determined along with protein analysis of eNOS, p-eNOS and inducible nitric oxide synthase (iNOS.At four weeks, survival was 80% in MI-pGz vs 50% in MI-CONT (p< 0.01. Ejection fraction and fractional shortening and invasive pressure volume relation indices of afterload and contractility were significantly better in MI-pGz. The latter where associated with decreased infarct transmurality and decreased fibrosis along with increased eNOS, p-eNOS. Additionally, MI-pGz had significantly lower levels of iNOS, inflammatory cytokines (IL-6, TNF-α, and higher level of anti

  12. Non-Invasive Technology That Improves Cardiac Function after Experimental Myocardial Infarction: Whole Body Periodic Acceleration (pGz) (United States)

    Kurlansky, Paul; Altamirano, Francisco; Lopez, Jose R.


    Myocardial infarction (MI) may produce significant inflammatory changes and adverse ventricular remodeling leading to heart failure and premature death. Pharmacologic, stem cell transplantation, and exercise have not halted the inexorable rise in the prevalence and great economic costs of heart failure despite extensive investigations of such treatments. New therapeutic modalities are needed. Whole Body Periodic Acceleration (pGz) is a non-invasive technology that increases pulsatile shear stress to the endothelium thereby producing several beneficial cardiovascular effects as demonstrated in animal models, normal humans and patients with heart disease. pGz upregulates endothelial derived nitric oxide synthase (eNOS) and its phosphorylation (p-eNOS) to improve myocardial function in models of myocardial stunning and preconditioning. Here we test whether pGz applied chronically after focal myocardial infarction in rats improves functional outcomes from MI. Focal MI was produced by left coronary artery ligation. One day after ligation animals were randomized to receive daily treatments of pGz for four weeks (MI-pGz) or serve as controls (MI-CONT), with an additional group as non-infarction controls (Sham). Echocardiograms and invasive pressure volume loop analysis were carried out. Infarct transmurality, myocardial fibrosis, and markers of inflammatory and anti-inflammatory cytokines were determined along with protein analysis of eNOS, p-eNOS and inducible nitric oxide synthase (iNOS).At four weeks, survival was 80% in MI-pGz vs 50% in MI-CONT (p< 0.01). Ejection fraction and fractional shortening and invasive pressure volume relation indices of afterload and contractility were significantly better in MI-pGz. The latter where associated with decreased infarct transmurality and decreased fibrosis along with increased eNOS, p-eNOS. Additionally, MI-pGz had significantly lower levels of iNOS, inflammatory cytokines (IL-6, TNF-α), and higher level of anti

  13. Evaluation of the asynchronization and function of the left ventricle in patients with chronic pulmonary hypertension by velocity vector imaging

    Institute of Scientific and Technical Information of China (English)

    WANG Chao-hong; WANG Yue-heng; NIU Ning-ning; XIE Ying-xin; WANG Lin


    Background Pulmonary hypertension (PH) is a set of pathophysiological syndromes characterized by increased pulmonary artery pressure and pulmonary vascular resistance,resulting in increased right ventricular afterload.The left and right ventricles interact through hemodynamics.What impact will PH have on synchronization and function of the left ventricle (LV)? The aim of this study was to evaluate the synchronization of the left ventricular wall motion and left ventricular function in patients with varying degrees of PH using velocity vector imaging (Wl) technology.Methods Sixty patients with chronic PH served as the experimental group,and 20 healthy volunteers served as the control group.According to the different degrees of pulmonary artery systolic pressure,the experimental group was divided into three groups:mild,moderate,and severe PH groups.The time to peak systolic longitudinal velocity (Tvl),the peak systolic longitudinal velocity (Vsl),the peak diastolic longitudinal velocity (Vel),the peak systolic longitudinal strain (SI),and strain rate (SRI) in 18 segments were measured in each group.Results TvI in the control group and each group with PH was reduced from basal to apical segment,and in control group Tvl in various segments of the same wall and in different walls showed no significant difference (P >0.05).With increase in pulmonary artery pressure,Tvl values measured showed an increasing trend in groups with PH.In groups with PH,Vsl and Vel of each wall were reduced sequentially from basal to apical segments,showing gradient change; Vsl and Vel values measured showed a decreasing trend with increase in pulmonary artery pressure,in which the differences of Vel values measured in the control group and the mild PH group were statistically significant (P <0.01),and the differences between other groups were statistically significant (P <0.01).In groups with PH,SI and SRI in basal segment and the middle segment of each wall were decreased; the

  14. 一种植入式磁悬浮离心血泵的体外流体力学实验研究%Experimental Study of Hydrodynamic in Vitro of an Implantable Magnetic Levitation Blood Pump

    Institute of Scientific and Technical Information of China (English)

    郭龙辉; 张杰民; 赵龙; 刘晓程


    To study hydrodynamic in vitro of an implantahle magnetic levitation blood pump using vitro test loop. The fresh sheep blood was prepared for the circulating medium. The output of the pump was tested at the different speeds against 100 mmHg; by controlling the pump's speed, the output of the pump was tested against different afterload.The blood pump worked at 24 V and the electric current was 0.3-0.75 A. Power consumption of the pump was 7.2-18 W. At 2 900-3 900 rpm, the pump generated 3~7.1L/min flow against 10.0 mmHg. At 2500~3500 rpm, the pump generated 1.02~5.87 L/min flow against 69~63 mmHg. The relationship between pressure and flow was negative correlation at fixed pump's speed. The blood pump works stably in vitro test. The pump can meet the need of adult's ventricular assist, but power consumption of the pump needs further improvement.%通过体外模拟循环实验台对一种植入式磁悬浮离心血泵进行体外流体力学实验.以新鲜羊血为循环介质,通过体外循环台测定在后负荷为100 mmHg,血泵在不同转速下的输出量;通过控制血泵的转速,测定在固定泵速下不同后负荷下的输出量.血泵测试工作电压为24V,电流波动于0.3~0.75 A.血泵功率为7.2~18W.在后负荷为100 mmHg下,泵速在2 900~3 900 rpm,输出流量为3~7.1 L/min.泵速为2 500~3 500rpm,血泵在后负荷69~ 163 mmHg下输出流量为1.02 ~ 5.87 L/min.在固定的转速下血泵的压力-流量呈负相关关系.体外实验血泵工作性能稳定,可以满足成人心室辅助的需求.血泵功率偏高仍需要进一步改进.

  15. Initial hydrodynamic study on a new intraaortic axial flow pump: Dynamic aortic valve

    Institute of Scientific and Technical Information of China (English)


    Rotary blood pumps have been researched as implantableventricular assist devices for years. To further reduce the complex of implanted axial pumps, the authors proposed a new concept of intraaortic axial pump, termed previously as "dynamic aortic valve (DAV)". Instead of being driven by an intraaortic micro-electric motor, it was powered by a magnetic field from outside of body. To ensure the perfusion of coronary artery, the axial flow pump is to be implanted in the position of aortic valve. It could serve as either a blood pump or a mechanical valve depending on the power input. This research tested the feasibility of the new concept in model study. A column, made from permanent magnet, is jointed to an impeller in a concentric way to form a "rotor-impeller". Supported by a hanging shaft cantilevered in the center of a rigid cage, the rotor-impeller can be turned by the magnetic field in the surrounding space. In the present prototype, the rotor is 8 mm in diameter and 15 mm in length, the impeller has 3 vanes with an outer diameter of 18 mm. The supporting cage is 22 mm in outer diameter and 20 mm in length. When tested, the DAV prototype is inserted into the tube of a mock circuit. The alternative magnetic field is produced by a rotating magnet placed side by side with the rotor-impeller at a distance of 30 mm. Once the alternative magnetic field is presented in the surrounding space, the DAV starts to turn, leading to a pressure difference and liquid flow in the tube. The flow rate or pressure difference is proportioned to rotary speed. At the maximal output of hydraulic power, the flow rate reached 5 L/min against an afterload of 100 mmHg. The maximal pressure difference generated by DAV at a rotation rate of 12600 r/min was 147 mmHg. The preliminary results demonstrated the feasibility of "DAV", further research on this concept is justifiable.

  16. Role of permissive hypotension, hypertonic resuscitation and the global increased permeability syndrome in patients with severe hemorrhage: adjuncts to damage control resuscitation to prevent intra-abdominal hypertension. (United States)

    Duchesne, Juan C; Kaplan, Lewis J; Balogh, Zsolt J; Malbrain, Manu L N G


    Secondary intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are closely related to fluid resuscitation. IAH causes major deterioration of the cardiac function by affecting preload, contractility and afterload. The aim of this review is to discuss the different interactions between IAH, ACS and resuscitation, and to explore a new hypothesis with regard to damage control resuscitation, permissive hypotension and global increased permeability syndrome. Review of the relevant literature via PubMed search. The recognition of the association between the development of ACS and resuscitation urged the need for new approach in traumatic shock management. Over a decade after wide spread application of damage control surgery damage control resuscitation was developed. DCR differs from previous resuscitation approaches by attempting an earlier and more aggressive correction of coagulopathy, as well as metabolic derangements like acidosis and hypothermia, often referred to as the 'deadly triad' or the 'bloody vicious cycle'. Permissive hypotension involves keeping the blood pressure low enough to avoid exacerbating uncontrolled haemorrhage while maintaining perfusion to vital end organs. The potential detrimental mechanisms of early, aggressive crystalloid resuscitation have been described. Limitation of fluid intake by using colloids, hypertonic saline (HTS) or hyperoncotic albumin solutions have been associated with favourable effects. HTS allows not only for rapid restoration of circulating intravascular volume with less administered fluid, but also attenuates post-injury oedema at the microcirculatory level and may improve microvascular perfusion. Capillary leak represents the maladaptive, often excessive, and undesirable loss of fluid and electrolytes with or without protein into the interstitium that generates oedema. The global increased permeability syndrome (GIPS) has been articulated in patients with persistent systemic inflammation failing

  17. Current status and potential perspectives in classical radiotherapy technology

    Directory of Open Access Journals (Sweden)

    Dabić-Stanković Kata M.


    Full Text Available Introduction and potentials of classical radiotherapy After purchase of radiotherapy equipment in 2003, classic radiation therapy in Serbia will reach the highest world level. In order to define the highest standards in radiation technology, we analyzed the current status and potential perspectives of radiation therapy. Technological levels of radiotherapy in developed countries An analysis of present situation in the USA, assumed as the most developed in the world, was done. Available data, collected in the last 3 years (equipment assortment, therapy modalities, workload and manpower for 284 radiotherapy centers, out of potential 2050, were analyzed. Results were presented as crude percentage and mached to point current status. Results of analysis and discussion The analysis showed that CLINAC accelerators are the most popular (82.7%, as well as, ADAC (43.7% and Focus (CMS (27.4% systems for therapy planning. Movement towards virtual simulation is evident (59.3%, although classic ”simulation” is not fully eliminated from the radiotherapy chain. The most popular brachytherapy afterloader is Microselectron HDR (71%. About 64.4% centers use IMPAC communication/verification/record system that seems more open than Varis. All centers practice modern radiotherapy modalities and techniques (CFRT, IMRT, SRS/SRT, TBI, IORT, IVBHRT, HDR BHRT, etc.. CT and MRI availability is out of question, but PET is available in 3% of centers, however this percentage is rapidly growing. Up to 350 new patients per year are treated by one accelerator (about 35 pts. a day. Centers are relatively small and utilize 2-3 accelerators on average. Average FTE staffing norm is 4 radiation oncologists, 2-3 medical radiotherapy physicists, about 3 certified medical dosimetrists and about 6 radiotherapy technologists. Technological aspects and conclusion In the past 5 years relative stagnation in classic radiotherapy has been observed. In spite of substantial investments in

  18. Total aortic arch replacement: superior ventriculo-arterial coupling with decellularized allografts compared with conventional prostheses.

    Directory of Open Access Journals (Sweden)

    Alexander Weymann

    Full Text Available To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts.After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group. Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees, arterial elastance (Ea and ventriculoarterial coupling were calculated. Characteristic impedance (Z was assessed by Fourier analysis.While Ees did not differ between the groups and over time (4.1±1.19 vs. 4.58±1.39 mmHg/mL and 3.21±0.97 vs. 3.96±1.16 mmHg/mL, Ea showed a higher increase in the prosthesis group (4.01±0.67 vs. 6.18±0.20 mmHg/mL, P<0.05 in comparison to decellularized allografts (5.03±0.35 vs. 5.99±1.09 mmHg/mL. This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5±50.9 vs. 3.9±23.4%. Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6±8.3 dyn·sec·cm(-5 vs. 32.4±2.0 dyn·sec·cm(-5, P<0.05.Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving

  19. Research progress of nuclear factor kappa B signaling pathway in pulmonary hypertension%核因子κB信号通路在肺动脉高压中作用的研究进展

    Institute of Scientific and Technical Information of China (English)

    张萌; 杨媛华


    Pulmonary hypertension (PH) is characterized by sustained increased pulmonary vascular resistance which leads to an increased afterload of right ventricle,right ventricle hypertrophy and finally,right heart failure.Nuclear factor kappa B (NF-κB) is a key transcription factor involved in inflammatory response,endothelia dysfunction,thrombosis and genetics which all participate in the development of PH.The development of PH could be attenuated by blocking NF-κB signaling pathway specifically.More detailed mechanism of NF-κB signaling pathway and novel selective NF-κB inhibitors have to be established,which may provide the new theory basis of pathogenesis of PH and the potential therapeutic opinion in the future.%肺动脉高压(pulmonary hypertension,PH)是由多种病因及病理生理机制引起的以肺血管阻力增高为特征的一组疾病,持续的肺血管阻力增高导致右心室后负荷增加,从而产生右心室肥厚及右心衰竭.核因子κB (nuclear factor kappa B,NF-κB)是一类具有多向转录调节作用的核转录因子.NF-κB可通过促进局部炎症反应、内皮细胞功能紊乱、血栓形成、氧化应激等病理生理过程,参与PH的形成和发展.特异的阻滞NF-cB信号通路可有效地延缓PH进程.进一步明确NF-κB在PH中的具体作用机制,研发能够针对NF-κB信号通路的靶向药物,将为PH发病机制探讨提供新的理论依据,并可能成为PH治疗新的靶点.

  20. Defining the role of calcium channel antagonists in heart failure due to systolic dysfunction. (United States)

    Mahé, Isabelle; Chassany, Olivier; Grenard, Anne-Sophie; Caulin, Charles; Bergmann, Jean-François


    Calcium channel antagonists (CCAs) may either be divided into the dihydropyridines (e.g. amlodipine, felodipine, isradipine, lacidipine, nilvadipine, nifedipine, nicardipine etc.), the phenylalkylamines (e.g. verapamil) and the benzothiazepines (e.g. diltiazem) according to their chemical structure, or into first generation agents (nifedipine, verapamil and diltiazem) and second generation agents (subsequently developed dihydropyridine-derivatives). Second generation CCAs are characterized by greater selectivity for calcium channels in vascular smooth muscle cells than the myocardium, a longer duration of action and a small trough-to-peak variation in plasma concentrations. Heart failure is characterized by decreased cardiac output resulting in inadequate oxygen delivery to peripheral tissues. Although the accompanying neurohormonal activation, leading to vasoconstriction and increased blood pressure, is initially beneficial in increasing tissue perfusion, prolonged activation is detrimental because it increases afterload and further reduces cardiac output. At the level of the myocyte, heart failure is associated with increased intracellular calcium levels which are thought to impair diastolic function. These changes indicate that the CCAs would be beneficial in patients with heart failure. There has been a strong interest and increasing experience in the use of CCAs in patients with heart failure. Despite potential beneficial effects in initial small trials, findings from larger trials suggest that CCA may have detrimental effects upon survival and cardiovascular events. However, this may not necessarily be a 'class b' effect of the CCAs as there is considerable heterogeneity in the chemical structure of individual agents. Clinical experience with different CCAs in patients with heart failure includes trials that evaluated their effects on hemodynamic parameters, exercise tolerance and on symptomatology. However, the most relevant results are those from randomized

  1. High dose rate brachytherapy using custom made superficial mould applicators and Leipzig applicators for non melanoma localized skin cancer

    Energy Technology Data Exchange (ETDEWEB)

    Pellizzon, A. Cassio A.; Miziara, Daniela; Lima, Flavia Pedroso de; Miziara, Miguel


    Purpose: advances in technology and the commercial production of Leipzig applicators allowed High Dose Rate after-load brachytherapy (HDR-BT) to address a number of the challenges associated with the delivery of superficial radiation to treat localized non melanoma skin cancer (NMSK). We reviewed our uni-institutional experience on the treatment of NMSK with HDR-BT. Methods: data were collected retrospectively from patients attending the Radiation Oncology Department at AV Carvalho Insitute, Sao Paulo, Brazil. HDR-BT was done using the stepping source HDR 192Ir Microselectron (Nucletron BV). The planning target volume consisted of the macroscopic lesion plus a 5mm to 10mm margin.The depth of treatment was 0.5 cm in smaller (< 2.0 cm) tumors and 10 to 15 mm for lesions bigger than that. Results: Thirteen patients were treated with HDR-BT from June, 2007 to June 2013. The median age and follow up time were 72 (38-90) years old and 36 (range, 7-73) months, respectively. There a predominance of males (61.5%) and of patients referred for adjuvant treatment due positive surgical margins or because they have had only a excision biopsy without safety margins (61.5%). Six (46.2%) patients presented with squamous cell carcinoma and 7 (53.8%) patients presented with basal cell carcinoma. The median tumor size was 20 (range, 5-42) mm. Patients were treated with a median total dose of 40 Gy (range, 20 -60), given in 10 (range, 2-15) fractions, given daily or twice a week. All patients responded very well to treatment and only one patient has failed locally so far, after 38 months of the end of the irradiation. The crude and actuarial 3-year local control rates were 100% and 80%, respectively. Moist desquamation, grade 2 RTOG, was observed in 4 (30.8%) patients. Severe late complication, radiation-induced dyspigmentation, occurred in 2 patients and 1 of the patients also showed telangiectasia in the irradiated area. The cosmetic result was considered good in 84% (11/13) patients

  2. Water equivalent phantom materials for 192Ir brachytherapy (United States)

    Schoenfeld, Andreas A.; Harder, Dietrich; Poppe, Björn; Chofor, Ndimofor


    Several solid phantom materials have been tested regarding their suitability as water substitutes for dosimetric measurements in brachytherapy with 192Ir as a typical high energy photon emitter. The radial variations of the spectral photon fluence, of the total, primary and scattered photon fluence and of the absorbed dose to water in the transversal plane of the tested cylindrical phantoms surrounding a centric and coaxially arranged Varian GammaMed afterloading 192Ir brachytherapy source were Monte-Carlo simulated in EGSnrc. The degree of water equivalence of a phantom material was evaluated by comparing the radial dose-to-water profile in the phantom material with that in water. The phantom size was varied over a large range since it influences the dose contribution by scattered photons with energies diminished by single and multiple Compton scattering. Phantom axis distances up to 10 cm were considered as clinically relevant. Scattered photons with energies reaching down into the 25 keV region dominate the photon fluence at source distances exceeding 3.5 cm. The tested phantom materials showed significant differences in the degree of water equivalence. In phantoms with radii up to 10 cm, RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR phantoms show excellent water equivalence with dose deviations from a water phantom not exceeding 0.8%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene show deviations up to 2.6%. For larger phantom radii up to 30 cm, the deviations for RW1, RW3, Solid Water, HE Solid Water, Virtual Water, Plastic Water DT, and Plastic Water LR remain below 1.4%, while Original Plastic Water (as of 2015), Plastic Water (1995), Blue Water, polyethylene, and polystyrene produce deviations up to 8.1%. PMMA plays a separate role, with deviations up to 4.3% for radii not exceeding 10 cm, but below 1% for radii up to 30 cm. As suggested by

  3. Combined transperineal radiofrequency (RF) interstitial hyperthermia and brachytherapy for localized prostate cancer (PC)

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    Urakami, Shinji; Gonda, Nobuko; Kikuno, Nobuyuki [Shimane Medical Univ., Izumo (Japan)] (and others)


    Hyperthermia has been used effectively as a radiation sensitizer. Interstitial hyperthermoradiotherapy has been therefore utilized as a minimal invasive therapy in attempts to improve local tumor control for various cancers, but not for urological cancer. The purpose of this study was to investigate the safety and feasibility of transperineal hyperthermoradiotherapy for localized PC. Based on our basic study of hyperthermoradiotherapy, we devised the procedure of combined transperineal RF interstitial hyperthermia and brachytherapy for localized prostate cancer. Two patients with localized PC underwent transperineal RF interstitial hyperthermia combined with brachytherapy operation the 192-Ir remote after-loading system (RALS). Under transrectal ultrasound guidance, a total number of 12-18 stainless steel needles for 192-Ir RALS were implanted into the prostatic gland and seminal vesicles (SV) in an optimized pattern. Eight of the needles were used as electrodes for hyperthermia, and were electrically insultated using the vinyl catheter along the length of the subdermal fatty tissue to protect from overheating. Three other needles were utilized for continuous temperature mapping in the prostate. Rectal temperature was also monitored. Total radiation doses of 70 Gy to the prostate and SV were planned as a combination of brachytherapy (24 Gy/4 fraction) and external irradiation using a four-field box technique (46 Gy/23 fraction). Hyperthermic treatment (goal of 42 to 43 deg C for 60 minutes) was performed twice following the 1st and 4th brachytherapy at an interval of more than 48 hours for the recovery of cancer cells from thermotolerance. Both patients reached the treatment goal of all intraprostatic temperatures >43.0 deg C, which was considered favorable for hyperthermia, and the rectal temperatures of both patients remained <38 deg C during hyperthermia. In serial PSA measurements of both patients, serum PSA was less than 1.0 ng/ml within 3 months and has since

  4. Customized individual applicators for endocavitary brachytherapy in patients with cancers of the nasal cavity, sinonasal region and nasopharynx. (United States)

    Kadah, Basel Al; Niewald, Marcus; Papaspyrou, George; Dzierma, Yvonne; Schneider, Mathias; Schick, Bernhard


    Brachytherapy has become an established therapeutic regimen for primary, persistent, recurrent and metastatic tumour disease in the head and neck region. This study presents the authors' preliminary experience with intracavitary brachytherapy by means of an individual silicone applicator in the treatment of patients with nasal, sinonasal, orbital and nasopharyngeal cancer. Between January 2001 and January 2013, twenty patients with cancer of the nasal cavity, the paranasal sinuses and nasopharynx underwent surgery and intracavitary brachytherapy with the aid of an individually manufactured silicone applicator in the Department of Otolaryngology, Head and Neck Surgery and in the Department of Radiotherapy and Radiooncology at the Saarland University Medical Center of Homburg, Germany. The tumour was localized in the nasal cavity/paranasal sinuses (15) affecting the orbit twice and the nasopharynx (5). There were 14 patients with squamous cell carcinoma, 2 patients with mixed tumours and one patient with adenocarcinoma, adenoid cystic carcinoma, mucosal melanoma or plasmocytoma. The majority of the patients presented with advanced disease (T3 or T4 tumours). In 18/20 patients, brachytherapy was performed as a boost technique, in the remaining two solely because of a previous radiation series. All surgical interventions were performed endonasally. Three to six weeks after surgery, a cast of the nasal cavity was created under general anaesthesia. Subsequently, an individual brachytherapy silicon applicator with two to four plastic tubes was manufactured. The radiation therapy was applied using the Ir-192 high-dose-rate-afterloading method (total dose 10-20 Gy) in two to five sessions, additionally in 18/20 patients a percutaneous radiotherapy with a total dose of 30-60 Gy was applied. After a mean duration of follow-up of 2 years, 7/20 patients experienced a local progression, 5/19 a regional recurrence in the neck nodes and 4/19 distant metastases. The 2-year

  5. Actualizacin en el diagnstico y tratamiento de la hipertensin pulmonar Update in the diagnosis and treatment of pulmonary hypertension

    Directory of Open Access Journals (Sweden)

    Juan A. Mazzei


    Full Text Available El trmino hipertensin pulmonar agrupa a un conjunto heterogneo de enfermedades que tienen en comn una remodelacin obstructiva del lecho vascular pulmonar. Esta alteracin provoca un estado hemodinmico caracterizado por una elevacin sostenida de la presin del circuito arterial pulmonar. La morbilidad y mortalidad de esta enfermedad son la consecuencia del fracaso de la compensacin del ventrculo derecho a este aumento de la poscarga. La presuncin clnica y el diagnstico precoz, una estratificacin adecuada basada en las causas subyacentes y los diferentes territorios vasculares comprometidos, la respuesta a los frmacos y el grado de gravedad, la seleccin de las diferentes alternativas teraputicas y su indicacin oportuna son los objetivos para el tratamiento contemporneo ptimo de los enfermos con hipertensin pulmonar y ser una importante tarea en el futuro. Estas recomendaciones estn destinadas al mdico general y tienen por objeto facilitar la deteccin precoz, el diagnstico y el tratamiento de los pacientes con hipertensin pulmonar, y pueden representar una diferencia significativa en el pronstico. Adems, como la evaluacin diagnstica requiere exmenes complementarios que habitualmente no estn disponibles en todas las instituciones asistenciales, tambin pueden ser utilizadas como fundamento para solicitar la derivacin oportuna a centros asistenciales de referencia.The term pulmonary hypertension includes a heterogeneous group of disorders which produce an obstructive remodeling of the lung vessels characterized by a steady rise in pulmonary arterial pressure. The ensuing morbidity and mortality of this disease result from the failure of the right ventricle to compensate this increase in the after-load. The conditions to achieve an optimum treatment of pulmonary hypertension patients are: a clinical presumption and early diagnosis, an adequate stratification based on the underlying causes and the different vascular territories involved, the response to

  6. Arterial stiffness: pathophysiology and clinical impact. (United States)

    London, Gérard M; Marchais, Sylvain J; Guerin, Alain P; Pannier, Bruno


    The ill effects of hypertension are usually attributed to a reduction in the caliber or the number of arterioles, resulting in an increase in total peripheral resistance (TPR). This definition does not take into account the fact that BP is a cyclic phenomenon with systolic and diastolic BP being the limits of these oscillations. The appropriate term to define the arterial factor(s) opposing LV ejection is aortic input impedance which depends on TPR, arterial distensibility (D), and wave reflections (WR). D defines the capacitive properties of arterial stiffness, whose role is to dampen pressure and flow oscillations and to transform pulsatile flow and pressure in arteries into a steady flow and pressure in peripheral tissues. Stiffness is the reciprocal value of D. These parameters are BP dependent, and arteries become stiffer at high pressure. In to D which provides information about the elasticity> of artery as a hollow structure, the elastic incremental modulus (Einc) characterizes the properties of the arterial wall biomaterials, independently of vessel geometry. As an alternative, arterial D can be evaluated by measuring the pulse wave velocity (PWV) which increases with the stiffening of arteries. Arterial stiffening increases left ventricular (LV) afterload and alters the coronary perfusion. With increased PWV, the WR impacts on the aorta during systole, increasing systolic pressures and myocardial oxygen consumption, and decreasing diastolic BP and coronary flow. The arterial stiffness is altered primarily in association with increased collagen content and alterations of extracellular matrix (arteriosclerosis) as classically observed during aging or in arterial hypertension. The arterial stiffening estimated by changes in aortic PWV and intensity of WR are independent predictors of survival in end stage renal disease (ESRD) and general population. Improvement of arterial stiffening could be obtained by antihypertensive treatmen as observed with the calcium

  7. ENT COBRA (Consortium for Brachytherapy Data Analysis): interdisciplinary standardized data collection system for head and neck patients treated with interventional radiotherapy (brachytherapy) (United States)

    Tagliaferri, Luca; Kovács, György; Budrukkar, Ashwini; Guinot, Jose Luis; Hildebrand, Guido; Johansson, Bengt; Monge, Rafael Martìnez; Meyer, Jens E.; Niehoff, Peter; Rovirosa, Angeles; Takàcsi-Nagy, Zoltàn; Dinapoli, Nicola; Lanzotti, Vito; Damiani, Andrea; Soror, Tamer; Valentini, Vincenzo


    Purpose Aim of the COBRA (Consortium for Brachytherapy Data Analysis) project is to create a multicenter group (consortium) and a web-based system for standardized data collection. Material and methods GEC-ESTRO (Groupe Européen de Curiethérapie – European Society for Radiotherapy & Oncology) Head and Neck (H&N) Working Group participated in the project and in the implementation of the consortium agreement, the ontology (data-set) and the necessary COBRA software services as well as the peer reviewing of the general anatomic site-specific COBRA protocol. The ontology was defined by a multicenter task-group. Results Eleven centers from 6 countries signed an agreement and the consortium approved the ontology. We identified 3 tiers for the data set: Registry (epidemiology analysis), Procedures (prediction models and DSS), and Research (radiomics). The COBRA-Storage System (C-SS) is not time-consuming as, thanks to the use of “brokers”, data can be extracted directly from the single center's storage systems through a connection with “structured query language database” (SQL-DB), Microsoft Access®, FileMaker Pro®, or Microsoft Excel®. The system is also structured to perform automatic archiving directly from the treatment planning system or afterloading machine. The architecture is based on the concept of “on-purpose data projection”. The C-SS architecture is privacy protecting because it will never make visible data that could identify an individual patient. This C-SS can also benefit from the so called “distributed learning” approaches, in which data never leave the collecting institution, while learning algorithms and proposed predictive models are commonly shared. Conclusions Setting up a consortium is a feasible and practicable tool in the creation of an international and multi-system data sharing system. COBRA C-SS seems to be well accepted by all involved parties, primarily because it does not influence the center's own data storing

  8. Effect of changes in intrathoracic pressure on cardiac function at rest and during moderate exercise in health and heart failure. (United States)

    Lalande, Sophie; Luoma, Charles E; Miller, Andrew D; Johnson, Bruce D


    This study investigated the effect of changes in inspiratory intrathoracic pressure on stroke volume at rest and during moderate exercise in patients with heart failure and reduced ejection fraction (HFREF) as well as healthy individuals. Stroke volume was obtained by echocardiography during 2 min of spontaneous breathing (S), two progressive levels of inspiratory unloading (UL1 and UL2) using a ventilator, and two progressive levels of inspiratory loading using resistors in 11 patients with HFREF (61 ± 9 years old; ejection fraction 32 ± 4%; NYHA class I-II) and 11 age-matched healthy individuals at rest and during exercise at 60% of maximal aerobic capacity on a semi-recumbent cycle ergometer. At rest, inspiratory unloading progressively decreased stroke volume index (SVI; S, 35.2 ± 5.4 ml m(-2); UL1, 33.3 ± 5.1 ml m(-2); and UL2, 32.2 ± 4.4 ml m(-2)) in healthy individuals, while it increased SVI (S, 31.4 ± 4.6 ml m(-2); UL1, 32.0 ± 5.9 ml m(-2); and UL2, 34.0 ± 7.2 ml m(-2)) in patients with HFREF (P = 0.04). During moderate exercise, inspiratory unloading decreased SVI in a similar manner (S, 43.9 ± 7.1 ml m(-2); UL1, 40.7 ± 4.7 ml m(-2); and UL2, 39.9 ± 3.7 ml m(-1)) in healthy individuals, while it increased SVI (S, 40.8 ± 6.5 ml m(-2); UL1, 42.8 ± 6.9 ml m(-2); and UL2, 44.1 ± 4. ml m(-2)) in patients with HFREF (P = 0.02). Inspiratory loading did not significantly change SVI at rest or during moderate exercise in both groups. It is concluded that inspiratory unloading improved SVI at rest and during moderate exercise in patients with HFREF, possibly due to a reduction in left ventricular afterload.

  9. Long-term outcome after neoadjuvant radiochemotherapy in locally advanced noninflammatory breast cancer and predictive factors for a pathologic complete remission. Results of a multivariate analysis

    Energy Technology Data Exchange (ETDEWEB)

    Matuschek, C.; Boelke, E.; Roth, S.L. [Duesseldorf Univ. (Germany). Dept. of Radiation Oncology] [and others


    An earlier published series of neoadjuvant radiochemotherapy (NRT-CHX) in locally advanced noninflammatory breast cancer (LABC) has now been updated with a follow-up of more than 15 years. Long-term outcome data and predictive factors for pathologic complete response (pCR) were analyzed. Patients and methods: During 1991-1998, 315 LABC patients (cT1-cT4/cN0-N1) were treated with NRT-CHX. Preoperative radiotherapy (RT) consisted of external beam radiation therapy (EBRT) of 50 Gy (5 x 2 Gy/week) to the breast and the supra-/infraclavicular lymph nodes combined with an electron boost in 214 cases afterwards or - in case of breast conservation - a 10-Gy interstitial boost with {sup 192}Ir afterloading before EBRT. Chemotherapy was administered prior to RT in 192 patients, and concomitantly in 113; 10 patients received no chemotherapy. The update of all follow-up ended in November 2011. Age, tumor grade, nodal status, hormone receptor status, simultaneous vs. sequential CHX, and the time interval between end of RT and surgery were examined in multivariate terms with pCR and overall survival as end point. Results: The total pCR rate after neoadjuvant RT-CHX reached 29.2%, with LABC breast conservation becoming possible in 50.8% of cases. In initially node-positive cases (cN+), a complete nodal response (pN0) after NRT-CHX was observed in 56% (89/159). The multivariate analysis revealed that a longer time interval to surgery increased the probability for a pCR (HR 1.17 [95% CI 1.05-1.31], p < 0.01). However, in large tumors (T3-T4) a significantly reduced pCR rate (HR 0.89 [95% CI 0.80-0.99], p = 0.03) was obtained. Importantly, pCR was the strongest prognostic factor for long-term survival (HR 0.28 [95% CI 0.19-0.56], p < 0.001). Conclusion: pCR identifies patients with a significantly better prognosis for long-term survival. However, a long time interval to surgery (> 2 months) increases the probability of pCR after NRT-CHX. (orig.)

  10. Cardiac-specific genetic inhibition of nuclear factor-κB prevents right ventricular hypertrophy induced by monocrotaline. (United States)

    Kumar, Sandeep; Wei, Chuanyu; Thomas, Candice M; Kim, Il-Kwon; Seqqat, Rachid; Kumar, Rajesh; Baker, Kenneth M; Jones, W Keith; Gupta, Sudhiranjan


    Uncontrolled pulmonary arterial hypertension (PAH) results in right ventricular (RV) hypertrophy (RVH), progressive RV failure, and low cardiac output leading to increased morbidity and mortality (McLaughlin VV, Archer SL, Badesch DB, Barst RJ, Farber HW, Lindner JR, Mathier MA, McGoon MD, Park MH, Rosenson RS, Rubin LJ, Tapson VF, Varga J. J Am Coll Cardiol 53: 1573-1619, 2009). Although the exact figures of its prevalence are difficult to obtain because of the diversity of identifiable causes, it is estimated that the incidence of pulmonary hypertension is seven to nine cases per million persons in the general population and is most prevalent in the age group of 20-40, occurring more commonly in women than in men (ratio: 1.7 to 1; Rubin LJ. N Engl J Med 336: 111-117, 1997). PAH is characterized by dyspnea, chest pain, and syncope. Unfortunately, there is no cure for this disease and medical regimens are limited (Simon MA. Curr Opin Crit Care 16: 237-243, 2010). PAH leads to adverse remodeling that results in RVH, progressive right heart failure, low cardiac output, and ultimately death if left untreated (Humbert M, Morrell NW, Archer SL, Stenmark KR, MacLean MR, Lang IM, Christman BW, Weir EK, Eickelberg O, Voelkel NF, Rabinovitch M. J Am Coll Cardiol 43: 13S-24S, 2004; Humbert M, Sitbon O, Simonneau G. N Engl J Med 351: 1425-1436, 2004. LaRaia AV, Waxman AB. South Med J 100: 393-399, 2007). As there are no direct tools to assess the onset and progression of PAH and RVH, the disease is often detected in later stages marked by full-blown RVH, with the outcome predominantly determined by the level of increased afterload (D'Alonzo GE, Barst RJ, Ayres SM, Bergofsky EH, Brundage BH, Detre KM, Fishman AP, Goldring RM, Groves BM, Kernis JT, et al. Ann Intern Med 115: 343-349, 1991; Sandoval J, Bauerle O, Palomar A, Gomez A, Martinez-Guerra ML, Beltran M, Guerrero ML. Validation of a prognostic equation Circulation 89: 1733-1744, 1994). Various studies have been

  11. Fiber-coupled radioluminescence dosimetry with saturated Al{sub 2}O{sub 3}:C crystals: Characterization in 6 and 18 MV photon beams

    Energy Technology Data Exchange (ETDEWEB)

    Andersen, C.E., E-mail: [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Damkjaer, S.M.S.; Kertzscher, G. [Radiation Research Division, Riso National Laboratory for Sustainable Energy, Technical University of Denmark, DK-4000 Roskilde (Denmark); Greilich, S. [Department of Medical Physics in Radiation Oncology, German Cancer Research Center (DKFZ), D-69120 Heidelberg (Germany); Aznar, M.C. [Department of Radiation Oncology, Copenhagen University Hospital, DK-2100 Copenhagen (Denmark)


    Radioluminescence (RL) and optically stimulated luminescence (OSL) from carbon-doped aluminum oxide crystals can be used for medical dosimetry in external beam radiotherapy and remotely afterloaded brachytherapy. The RL/OSL signals are guided from the treatment room to the readout instrumentation using optical fiber cables, and in vivo dosimetry can be carried out in real time while the dosimeter probes are in the patient. The present study proposes a new improved readout protocol based solely on the RL signal from Al{sub 2}O{sub 3}:C. The key elements in the protocol are that Al{sub 2}O{sub 3}:C is pre-dosed with {approx}20 Gy before each measurement session, and that the crystals are not perturbed by optical stimulation. Using 6 and 18 MV linear accelerator photon beams, the new RL protocol was found to have a linear dose-response from 7 mGy to 14 Gy, and dosimetry in this range could therefore be performed using a single calibration factor ({approx}6 x 10{sup 6} counts per Gy for a 2 mg crystal). The reproducibility of the RL dosimetry was 0.3% (one relative standard deviation) for doses larger than 0.1 Gy. The apparent RL sensitivity was found to change with accumulated dose ((-0.45 {+-} 0.03)% per 100 Gy), crystal temperature ((-0.21 {+-} 0.01)%/ deg. C), and dose-delivery rate ((-0.22 {+-} 0.01)% per 100 MU/min). A temporal gating technique was used for separation of RL and stem signals (i.e. Cerenkov light and fluorescence induced in the optical fiber cable during irradiation). The new readout protocol was a substantial improvement compared with the combined RL/OSL protocol, that required relatively long readout times and where the optical stimulation greatly affected the RL sensitivity. The only significant caveat was the apparent change in RL-response with accelerator dose-delivery rate. - Highlights: > New readout protocol based only on the RL signal from pre-dosed Al{sub 2}O{sub 3}:C. > Fast readout. > Linear dose-response. > High-dynamic range (7 mGy-14

  12. Haemodynamics and oxygenation improvement induced by high frequency percussive ventilation in a patient with hypoxia following cardiac surgery: a case report

    Directory of Open Access Journals (Sweden)

    Persi Bruno


    did not change. Conclusion Although the high frequency percussive ventilation was started ten days after the conventional ventilation, it still improved the gas exchange. The reduction of right ventricular stroke work index, left ventricular stroke work index, pulmonary vascular resistance index and pulmonary arterial wedge pressure is directly related to the lower respiratory mean airway pressure and the consequent afterload reduction.

  13. Study of hydrodynamic in vitro and animal experiment of a homebred pneumatic pulsatile ventricular assist device%国产气动搏动性心室辅助装置的体外流体力学及动物实验观察

    Institute of Scientific and Technical Information of China (English)

    史国宁; 陈庆良; 陈彤云; 刘建实


    目的:对我国自主研发气动搏动性心室辅助装置进行体外流体力学检验及活体动物应用实验,检验其是否满足临床心室辅助装置要求。方法通过体外模拟循环实验台,30%甘油水溶液作为循环介质,接入心室辅助装置,测定不同模式下血泵的后负荷和流量,以此检测装置的流体力学效果。对6只实验犬应用心室辅助装置左心辅助模式1 h,之后药物KCl诱颤心脏,5 min后除颤。监测心室辅助装置对实验犬的心率、血压支持效果。结果心室辅助装置流体力学实验后负荷100 mmHg条件下,流量可达到4 L/min以上。实验犬经左室安装辅助装置后,各时间点心率无明显变化。辅助后即刻与辅助前相比收缩压升高约30 mmHg,舒张压升高约19 mmHg。辅助过程中未见明显血压波动。诱颤后可维持收缩压60 mmHg,除颤后撤除装置存活良好。结论该心室辅助装置所产生的流体压力可基本满足临床心室辅助要求,短期应用于实验犬有效、安全、稳定,长期使用效果尚需进一步实验证明。%Objective To study in vitro hydrodynamics of a pneumatic pulsatile ventricular assist device developed ex⁃clusively by China, and establish an animal model for the detection by the device. Methods The hydromechanics experi⁃ment was performed on an in vitro test loop using MEDOS-System to drive the ventricular assist device, and lycerl-water so⁃lution was used as circulating medium. The changes of afterload pressure and the output of the pump were monitored, and the impermeability and stability were also assessed after the experiment. Six adult dogs were used as the experimental animals. The device worked in the left heart assistance mode for 1 hour then the ventricular fibrillation was induced by potassium chloride, and then defibrillated after 5 min while the device remained working. The hemodynamics data were monitored con⁃secutively during

  14. 局部晚期宫颈癌螺旋断层放疗同步化疗早晚期不良反应和疗效观察%Acute and late toxicities and efficacy of helical tomotherapy and concurrent chemotherapy in the treatment of locally advanced cervical cancer

    Institute of Scientific and Technical Information of China (English)

    姚波; 王树鹤; 王雅棣; 刘清智; 路娜


    Objective To investigate the acute and late toxicities and 2-year treatment outcomes in cervical cancer pa-tients underwent helical tomotherapy (HT) with concurrent chemotherapy and high dose afterloading intraluminal brachy-therapy (HDR). Method 46 patients with cervical cancer of stage Ib-IIIb who had accepted radical radiotherapy were en-rolled in the study. HT-IMRT was utilized as the external irradiation. 14 patients with pelvic lymph nodes involvement were outlined and defined as GTVnd, and then clinical target volume included pelvic lymph nodes (6 patients received ex-tended-field irradiation), GTVnd, whole uterus, cervix and vagina, with an extent of 0.8~1 cm as the planning target vol-ume (PTV). The median prescribed dose for PTV was 50.4 Gy (45-50.4 Gy) at 1.8-2.0 Gy per fraction;All patients re-ceived concurrent chemotherapy with cisplatin at 40 mg/m2/w;After HT at 30-40 Gy, HDR was applied in combination, with a median dose of 30 Gy (30-36 Gy) at point A, and the overall equivalent 2 Gy dose (EQD2) was 90.3 Gy (84.9~98.3 Gy) at point A. Adverse reactions and efficacy were evaluated during treatment and 1~24 months thereafter. Result 24 patients completed 4-5 cycles of concurrent chemotherapy and 22 patients completed 2-3 cycles. Acute toxicities of grade 3 included: leukopenia, diarrhea, nausea and vomiting, each occurred in 9 (19.6%), 2 (4.3%), 5 (10.9%), and 1 (2.2%) patients, respectively. Late toxicities of grade 3 occurred in 2 patients, including 1 case with rectal bleeding and an-other 1 case with bladder bleeding. No grade 4 or 5 toxicities were observed. The 2-year recurrence-free survival, disease-free survival and overall survival were 91.7%, 86.0% and 97.1%, respectively. Conclusion Helical tomotherapy with concurrent chemotherapy and high dose afterloading intraluminal brachytherapy mainly causes leukopenia and nausea, which was a feasible therapy with minor late toxicities and satisfactory short-term efficacy.%目的:分析局部晚期

  15. Monte Carlo Dosimetry of the 60Co BEBIG High Dose Rate for Brachytherapy.

    Directory of Open Access Journals (Sweden)

    Luciana Tourinho Campos

    Full Text Available The use of high-dose-rate brachytherapy is currently a widespread practice worldwide. The most common isotope source is 192Ir, but 60Co is also becoming available for HDR. One of main advantages of 60Co compared to 192Ir is the economic and practical benefit because of its longer half-live, which is 5.27 years. Recently, Eckert & Ziegler BEBIG, Germany, introduced a new afterloading brachytherapy machine (MultiSource®; it has the option to use either the 60Co or 192Ir HDR source. The source for the Monte Carlo calculations is the new 60Co source (model Co0.A86, which is referred to as the new BEBIG 60Co HDR source and is a modified version of the 60Co source (model GK60M21, which is also from BEBIG.The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy to investigate the required treatment-planning parameters. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. To validate the source geometry, a few dosimetry parameters had to be calculated according to the AAPM TG-43U1 formalism. The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The spectrum to simulate 60Co was composed of two photon energies, 1.17 and 1.33 MeV. Only the gamma part of the spectrum was used; the contribution of the electrons to the dose is negligible because of the full absorption by the stainless-steel wall around the metallic 60Co. The XCOM photon cross-section library was used in subsequent simulations, and the photoelectric effect, pair

  16. Dosimetric characterization of the M-15 high-dose-rate Iridium-192 brachytherapy source using the AAPM and ESTRO formalism. (United States)

    Ho Than, Minh-Tri; Munro Iii, John J; Medich, David C


    The Source Production & Equipment Co. (SPEC) model M-15 is a new Iridium-192 brachytherapy source model intended for use as a temporary high-dose-rate (HDR) brachytherapy source for the Nucletron microSelectron Classic afterloading system. The purpose of this study is to characterize this HDR source for clinical application by obtaining a complete set of Monte Carlo calculated dosimetric parameters for the M-15, as recommended by AAPM and ESTRO, for isotopes with average energies greater than 50 keV. This was accomplished by using the MCNP6 Monte Carlo code to simulate the resulting source dosimetry at various points within a pseudoinfinite water phantom. These dosimetric values next were converted into the AAPM and ESTRO dosimetry parameters and the respective statistical uncertainty in each parameter also calculated and presented. The M-15 source was modeled in an MCNP6 Monte Carlo environment using the physical source specifications provided by the manufacturer. Iridium-192 photons were uniformly generated inside the iridium core of the model M-15 with photon and secondary electron transport replicated using photoatomic cross-sectional tables supplied with MCNP6. Simulations were performed for both water and air/vacuum computer models with a total of 4 × 109 sources photon history for each simulation and the in-air photon spectrum filtered to remove low-energy photons belowδ = 10 keV. Dosimetric data, including D·(r,θ), gL(r), F(r,θ), φan(r), and φ-an, and their statistical uncertainty were calculated from the output of an MCNP model consisting of an M-15 source placed at the center of a spherical water phantom of 100 cm diameter. The air kerma strength in free space, SK, and dose rate constant, Λ, also was computed from a MCNP model with M-15 Iridium-192 source, was centered at the origin of an evacuated phantom in which a critical volume containing air at STP was added 100 cm from the source center. The reference dose rate, D·(r0,θ0) ≡ D· (1cm

  17. 老年慢性心力衰竭合并低钠血症59例临床分析%Clinical Analysis of 59 Old Chronic Heart Failure Patients Complicated with Hyponatremia

    Institute of Scientific and Technical Information of China (English)

    杨云贵; 蔡吉芬; 胡东升; 丁绍平


    Objective To explore the influence of hyponatremia on older chronic heart failure and effective prevention and control measures. Methods We retrospectively analysed 126 old congestive heart failure patients over 60 in our hospital from January 2006 to June 2011, including 59 patients with hyponatremia (hyponatremia group) and 67 patients with normal blood sodium (control group). We compared the mortality, heart failure grade and the concentration of sodium blood between the two groups, and applied high permeability saline to correct hyponatremia and improve the curative effect of heart failure. Results The mortality of hyponatremia group was significantly higher than the control group (P < 0.01). The blood sodium levels of patients in moderate and severe heart failure groups were lower than light and medium heart failure group (P < 0.01). On the basis of conventional treatment including inhalating oxygen, giving cardiotonic, diuresis, and lessen the cardiac afterload, giving high-osmolar sodium chloride injection shortened the recover time of cardiac function. Conclusions For old chronic heart failure patients, the higher the level of heart failure and the lower the serum sodium level, the higher the mortality. Hyponatremia and mortality have a significant relationship. For the elderly patients with chronic heart failure in treatment process, we should regularly monitor the blood sodium concentration, reasonable use diuretics, so that early detection and correction hyponatremia, improve the success rate of chronic heart failure treatment. The high permeability sodium chloride injection can rapidly correct hyponatremia and significantly improve heart function.%目的 探讨低钠血症对老年慢性心力衰竭的影响及有效的防治措施.方法 回顾性分析曲靖市第一人民医院2006年1月至2011年6月60岁以上的慢性充血性心力衰竭住院患者126例,其中并发低钠血症者(低钠组)59例,正常血钠者(对照组)67例,比较两组


    Rosei, Enrico Agabiti


    , LV mass reproducibility represents one of the major technical limitations of echocardiography and LV mass calculation may be not reliable in patients with previous myocardial infarction or with asymmetrical hypertrophy, assuming a prolate ellipsoid shape for the left ventricle. For this reason LV mass measurement with cardiac magnetic resonance (CMR) imaging, which is indubitably more accurate and reproducible, has been proposed, but with obvious limitations related to availability and costs of the technique.Three-dimensional echocardiographic (3DEcho) imaging represents a relevant innovation in cardiovascular imaging. The development of fully sampled matrix-array transducers, together with significant improvements in hardware and software of ultrasound systems, has made possible excellent real-time imaging of the beating heart in 3D. More recent studies indicate that 3DEcho has an excellent accuracy and provides better correlations that 2-dimensional echocardiography with MRI measurements.Echocardiography may also give useful information on cardiac functional changes, including systolic and diastolic abnormalities. LV diastole may be accurately evaluated by assessment of transmitral flow velocities, mitral annular pulsed tissue Doppler imaging and left atrial volume assessment. In uncomplicated hypertensives LV systolic dysfunction, as assessed by LV shortening fraction (FS) and ejection fraction (EF), expressing endocardial fibers shortening are usually preserved or even "supernormal", while midwall FS is reduced. In the absence of major structural abnormalities, the TDI measurement of longitudinal myocardial systolic velocity has been proposed as a reliable index of myocardial performance, independent of LV preload and afterload.Compared to the conventional 2D traditional approach, 3D echo offers the opportunity for a more sophisticated assessment of LV function, by the improvement in the accuracy of the evaluation of left ventricular and left atrial volumes by

  19. 国产可植入式自悬浮心室辅助装置的体外实验%The hemolysis research and fatigue test in vitro of the national implantable ventricular assist device

    Institute of Scientific and Technical Information of China (English)

    Mugahed Albahde; 叶亮; 范慧敏; 刘中民


    Objective To evaluate the hemolysis and fatigue resistance self suspension ventricular assist device (NIVAD) in vitro.Methods Resettled NIVAD which is filled with 2 500 ml fresh anticoagulant blood from pig in vitro loop system.The speed of blood pump was adjusted to 8 000 rpm.The afterload and the flow of pump were set as 100 mmHg and 3.5 L/min respectively.Keep the temperature at around 37 degree centigrade which is equal to average internal temperature in pig.Then harvest and measure the free hemoglobin(FHB) of blood samples at different time points before and after working.Then calculated the normalized index of hemoylsis(NIH) by comparing to control group, the unused pig blood at the same period.In fatigue test, conditions remained unchanged, except the blood was replaced by pure water.The blood pump had operated for 90 d continuously and recorded its performance.Results The FHB of experimental blood is higher than that of the control.The normal index of hemolysis NIVAD is(0.0052 ±0.0019)mg/L.Fatigue test , the blood pump operated smoothly, and every parameters was stable.Conclusion The blood pump of NIVAD does a certain degree of destruction to blood, but the NIH is in criterion range of hemolysis, it has certain advantages compared to similar products in china and aboard.At the same time it has good resistance and stable property to fatigue.%目的 对国产可植入式自悬浮心室辅助装置(national implantable ventricular assist device,NIVAD)进行体外实验研究,评价溶血性能和耐疲劳稳定性.方法 将NIVAD安置于自行设计的体外测试平台中,充满新鲜抗凝猪血2 500 ml,设定血泵转速8 000转/min,后负荷100 mmHg(1 mmHg=0.133 kPa),流量3.5 L/min,恒温37℃,转泵前、后多个时间点取血样本测量游离血红蛋白(FHB),同时留置静置血液为对照组,分别计算血泵标准化溶血指数(NIH).疲劳实验将血液换为纯净水,条件不变,连续记录90天泵的各项参数.结果 与对照组相

  20. 柳珊瑚酸钠对豚鼠离体工作心脏及其缺血再灌注血流动力学的影响%Effect of sodium suberogorgin on hemodynamics and myocardial ischemic-reperfused injury in isolated guinea pig working hearts

    Institute of Scientific and Technical Information of China (English)

    许实波; 彭汶铎; 胡宇彤


    AIM: To study the actions of sodium suberogorgin (Sub) no normal-and myocardial ischemic-reperfuscd working hearts. METHODS: The isolated guinea pig working hearts were perfused with edetic acid(0.2 μmol·L-1)-Krebs-Henseleit solution by left pulmonary vein at 37±0.5℃. The perfusing pressure of left atrium and the afterload of left ventricle were maintained at 1.0 and 7.2 kPa, respectively. During 50-min low-flow global ischemic, coronary flow was maintained at 4.7±0.2% of normal working hearts via retrgogading perfusion. Reperfusion lasted 35 min following ischemia. RESULTS: Before ischemia, the aortic pressure, left ventricular systolic pressurd, the maximal rate of left ventricular pressure change (+dp/dtmax and –dp/dtmax), acrdiac output, stroke volume, left ventricular end-diastolic presure, and heart rate of working hearts treated with Sub 10 μmol·L-1 for 10 min were increased by 14%, 17%, 17%, 22%, 15%, 32%, -200%, and –11%, respectively. These parameters were reduced when Sub was increased to 50 μmol·L-1. Reperfusion aggravated the myocardial damages induced by ischemia. Sub 10μmol.L-1used before and during low-flow ischemia completely restored all above parameters except heart rate to the level of preischemia, When Sub was increased to 50 μmol.·L-1, only an attenuation of myocardial damage was observed. CONCLUSION: Sub obiously improved the ischmeicreperfused injury in isolated working hearts.%目的:研究柳珊瑚酸钠(suberogorgin,Sub)对正常和缺血再灌注损伤工作心脏的作用.方法:用含edetic acid 0.2μmol·L-1的克-亨氏液(37±0.5℃)从左肺静脉对心脏进行灌注.左房灌注压和左室负荷分别为1.0和7.2kPa.50 min低流缺血期间,冠脉流量为正常灌注时的4.7±0.2%,此后进行35 min的再灌注.结果:Sub 10μmol·L-1使正常工作心脏的AP,LVSP,+dp/dtmax,-dp/dtmax,CO和SV分另提高14%,17%,17%,22%,15%和32%,但使LVEDP和HR各下降200%和11%;Sub 50μmol·L-1则降低上述指标.对于

  1. The radiobiology of prostate cancer including new aspects of fractionated radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, Jack F. [Medical School of Wisconsin Univ., Madison (United States). Dept. of Human Oncology


    Total radiation dose is not a reliable measure of biological effect when dose-per-fraction or dose-rate is changed. Large differences in biological effectiveness (per gray) are seen between the 2 Gy doses of external beam radiotherapy and the large boost doses given at high dose-rate from afterloading sources. The effects are profoundly different in rapidly or slowly proliferating tissues, that is for most tumors versus late complications. These differences work the opposite way round for prostate tumors versus late complications compared with most other types of tumor. Using the Linear-Quadratic formula it is aimed to explain these differences, especially for treatments of prostate cancer. The unusually slow growth rate of prostate cancers is associated with their high sensitivity to increased fraction size, so a large number of small fractions, such as 35 or 40 'daily' doses of 2 Gy, is not an optimum treatment. Theoretical modeling shows a stronger enhancement of tumor effect than of late complications for larger (and fewer) fractions, in prostate tumors uniquely. Biologically Effective Doses and Normalized Total Doses (in 2 Gy fraction equivalents) are given for prostate tumor, late rectal reactions, and - a new development - acute rectal mucosa. Tables showing the change of fraction-size sensitivity (the alpha/beta ratio) with proliferation rates of tissues lead to the association of slow cell doubling times in prostate tumors with small alpha/beta ratios. Clinical evidence to confirm this biological expectation is reviewed. The alpha/beta ratios of prostate tumors appear to be as low as 1.5 Gy (95% confidence interval 1.3-1.8 Gy), in contrast with the value of about 10 Gy for most other types of tumor. The important point is that alpha/beta ratio=1.5 Gy appears to be significantly less than the alpha/beta ratio=3 Gy for late complications in rectal tissues. Such differences are also emerging from recent clinical results. From this important

  2. 多层放射性铬胶片剂量验证系统的研制%Development of multi-layer radiochromic film dose verification system

    Institute of Scientific and Technical Information of China (English)

    张可; 谢玲灵; 张中柱; 戴建荣


    and analysis are reduced, and physicist's workload is also diminished. The gamma index passing rate for 6 cases are all over 90%with 3% dose difference and 3mm DTA criteria. The system can be used for the machine QA, such as linear accelerator, gamma knife, cyber knife, afterloading unit, interstitial brachytherapy as well as the patient specific 2D and 3D IMRT plan QA. Conclusion:Multifilm QA system is a versatile tool for IMRT dose verification and regular quality assurance. It is convenient, accurate, authentic, huge amounts of information and multi-purpose, etc. It can be used in the dose verification for VMAT and IMRT plan besides daily quality assurance of accelerator.

  3. Low dose rate caesium-137 implant time of intracavitary brachytherapy source of a selected oncology center in Ghana

    Directory of Open Access Journals (Sweden)

    John Owusu Banahene


    Full Text Available Background: The treatment time taken for a radioactive source is found to be very important in intracavitary brachytherapy treatment. The duration of the treatment time depends on the prescribed dose requested to a reference point and the calculated dose rate to the same point. The duration of the treatment time of source is found to depend on the tumour stage. In this work, the treatment time of implant has been calculated for a Caesium-137 low dose rate brachytherapy source at an oncology facility in Ghana. Objective: The objective was to determine how the treatment time of tumours depends on the dose rate to the reference point prescribed by the Oncologists and the dose rate determined by the dosimetrists at the facility. Materials and Method: Depending upon the stage of the cancer, the Oncologist determines the type of treatment modality, source configuration for the cancer patient and positions of both tandem and ovoids in the cervix. Depending also on the tumour stage, two orthogonal radiographic X-ray films are taken using a simulator machine. The treatment machine used in the study is AMRA-Curietron. The maximum activity of the source was 259GBq. It has five channels which is a manual remote afterloader. In clinical practice, the treatment time t is very short(only some few days for such low dose rate brachytherapy source like Cs-137 which lasts only for some few days in comparison with the half life of the Cs-137 source. The mathematical equation for the calculation of treatment time is written as t=D/D. Hence t is the treatment time of the radioactive source of patients undergoing intracavitary brachytherapy treatment, D is prescribed dose to a reference point and D is the dose rate to the same reference point. Results: The calculated treatment time of the Cs-137 brachytherapy source for different source arrangements or channels used in clinical practice at the brachytherapy Centre have been determined. Also provided, are the

  4. Influence of pulmonary artery-left atrium pumpless pulmonary assist on right ventricular load in oleic-induced acute lung injury animal model%肺动脉-左心房无泵肺辅助对急性肺损伤动物模型右心室负荷影响

    Institute of Scientific and Technical Information of China (English)

    李晓锋; 王强; 朱耀斌; 刘迎龙; 慎慧; 刘晋萍


    .9) mm Hg at E point, which was significantly lowerthan B point (P=0. 047). There was significant difference in pulmonary artery pressure at D point, E point, respectively, between in the experimental group and contol group. Conclusion The pulmonary artery-left atrium lung assist is feasible to treat acute lung injury, and can reduce the afterload of right ventricle.

  5. Monte Carlo Dosimetry of the 60Co BEBIG High Dose Rate for Brachytherapy (United States)

    Campos, Luciana Tourinho; de Almeida, Carlos Eduardo Veloso


    Introduction The use of high-dose-rate brachytherapy is currently a widespread practice worldwide. The most common isotope source is 192Ir, but 60Co is also becoming available for HDR. One of main advantages of 60Co compared to 192Ir is the economic and practical benefit because of its longer half-live, which is 5.27 years. Recently, Eckert & Ziegler BEBIG, Germany, introduced a new afterloading brachytherapy machine (MultiSource®); it has the option to use either the 60Co or 192Ir HDR source. The source for the Monte Carlo calculations is the new 60Co source (model Co0.A86), which is referred to as the new BEBIG 60Co HDR source and is a modified version of the 60Co source (model GK60M21), which is also from BEBIG. Objective and Methods The purpose of this work is to obtain the dosimetry parameters in accordance with the AAPM TG-43U1 formalism with Monte Carlo calculations regarding the BEBIG 60Co high-dose-rate brachytherapy to investigate the required treatment-planning parameters. The geometric design and material details of the source was provided by the manufacturer and was used to define the Monte Carlo geometry. To validate the source geometry, a few dosimetry parameters had to be calculated according to the AAPM TG-43U1 formalism. The dosimetry studies included the calculation of the air kerma strength Sk, collision kerma in water along the transverse axis with an unbounded phantom, dose rate constant and radial dose function. The Monte Carlo code system that was used was EGSnrc with a new cavity code, which is a part of EGS++ that allows calculating the radial dose function around the source. The spectrum to simulate 60Co was composed of two photon energies, 1.17 and 1.33 MeV. Only the gamma part of the spectrum was used; the contribution of the electrons to the dose is negligible because of the full absorption by the stainless-steel wall around the metallic 60Co. The XCOM photon cross-section library was used in subsequent simulations, and the

  6. Extreme challenges on cardiovascular control during gravity transitions (United States)

    Verheyden, B.; Beckers, F.; Aubert, A. E.

    Introduction. During parabolic flights transient periods of hypergravity and microgravity are created. These periods cause translocations of bodily fluids in the longitudinal axis of the body, leading to altered cardiac preload and afterload. These extreme orthostatic challenges provide a unique platform to study baroreflex-mediated responses of the cardiovascular autonomic control system. This might have important features for the development of a model of cardiovascular deconditioning that is observed in a variety of patient populations. Purpose. Until now, due to methodological restrictions, most studies have been concentrating on the analysis of cardiovascular variability in time domain. The purpose of this study is to evaluate heart rate variability (HRV) and blood pressure variability (BPV) simultaneously, using frequency domain analysis techniques (low frequency power (LF: 0.04-0.15 Hz); high frequency power (HF: 0.16-0.4 Hz)), providing additional information about cardiac and vasomotor sympathetic modulation during gravity transitions. Methods. 12 healthy non-medicated volunteers (age = 24 ± 2.5 yr) underwent continuous ECG and blood pressure (BP) recordings during the 32nd and 34th parabolic flight campaign organized by ESA. The subjects performed 15 parabolas in supine and 15 parabolas in standing position. 5 transient gravity phases were abstracted; phase 1 and 5: before and after the parabola (1G); phase 2 and 4: at the ascending and descending leg of the parabola (2G); phase 3: at the apex of the parabola (0g). Phase 2, 3 and 4 last 20 seconds. Results. No significant differences were found in HRV and BPV parameters in supine position between the different gravity phases. In standing position, mean RR- interval was higher during 0G (900 ± 103 ms) compared to 1G (700 ± 87 ms) and 2G (600 ± 94 ms). Mean arterial BP remained relatively constant during 0G but tended to decrease during 2G (102 ± 2 mmHg vs. 105 ± 3 mmHg). Positive correlations were

  7. Short-term efficacy of paclitxel plus cisplatin combined with adiotherapy on advanced cervix cancer%紫杉醇联合顺铂方案同步放化疗治疗中晚期宫颈癌近期疗效观察

    Institute of Scientific and Technical Information of China (English)

    汪志求; 韩光锋; 段爱雄


    目的:观察紫杉醇联合顺铂方案同步放化疗治疗中晚期宫颈癌的近期疗效和不良反应.方法:选择Ⅱb~Ⅲb期宫颈癌36例同步放化疗,放疗分次量每次2 Gy,每周5次,总剂量50 Gy,体外照射开始后1周,采用192Ir高剂量率子宫腔内后装照射,腔内照射每周1次,A点剂量每次7Gy,共6次.放疗期间采用紫杉醇135 mg/m2,d1,顺铂25 mg/m2,d1~d3方案同步化疗,每3~4周重复,共2周期,观察近期疗效和不良反应.结果:36例患者完全缓解27例,部分缓解7例,进展2例,有效率94.4%.患者病理类型和临床分期间有效率差异均无统计学意义(P>0.05).不良反应主要为中性粒细胞下降和放射性直肠反应.结论:紫杉醇联合顺铂同步放化疗近期疗效肯定,不良反应可以耐受.%Objective: To observe the short-term efficacy and toxicity of paclitxel plus cisplatin combined with radiotherapy in treatment of advanced cervix cancer. Methods: Thirty-six patients with advanced cervix cancer ( II b- HI b ) received concurrent chemoradiotherapy. The external irradiation dose of radiotherapy was 2Gy per time,5d/W, with a total dose of 50Gy;l92Ir high-dose-rate afterloading unit was adopted for branchytherapy one week after external radiotherapy, at a dose of 7 Gy per time in A point for 6 times. Paclitxel ( 135mg/m2 , d1 ) and cisplatin ( 25mg/m2 , d1- d3 ) were given every 3-4 weeks for two cycles concurrently with radiotherapy. The short effectiveness and toxic reaction were observed in these patients. Results: Of the 36 cases, complete response was observed in 27 cases, partial response in 7 cases and two cases presented certain progress. The overall response rate was 94. 4% . There was no statistical significance in differences of patients' pathologic patterns and clinical stages( P > 0. 05 ). The main toxicities were leucopenia and radiation rectal reaction. Conclusions: The short term efficacy of concurrent chemoradiotherapy with paclitxel and cisplatin is

  8. The risk of prosthetic mismatch after transcatheter aortic valve implantation:a meta analysis%经导管主动脉瓣置换术后人工瓣膜-患者不匹配风险的Meta分析

    Institute of Scientific and Technical Information of China (English)

    王萌; 傅钢兰; 江慧琦; 曾宽; 华平; 徐忠东


    Objective Prosthesis-patient mismatch (PPM) leads to increased left ventricle afterload and influences the clinical outcome of postoperative patients. This Meta analysis aims to study risk factors of prosthesis-patient mismatch (PPM) after transcatheter aortic valve implantation (TAVI). Methods The data of prosthesis-patient mismatch after transcatheter aortic valve implantation was derived by searching Medline, Cochrane library, Scopus database. Studies with baseline data of PPM group and no PPM group were included in the Meta analysis. Results PPM patients had averaged body surface area of 1.87 ±0.202 m2,.age of 78.3 ±7.78 years old,.left ventricle ejection fraction of 41.0±14.1%,.effective orifice area index of 0.366±0.0922..Comparing with no PPM group,.PPM patients had larger body surface area ,.lower left ventricle ejection fraction and lower effective orifice area (P0.05). Conclusion Larger body surface area,lower left ventricle ejection fraction and more severe aortic stenosis are related to PPM.%目的:人工瓣膜-患者不匹配(Prosthesis-patient mismatch, PPM)使左心室后负荷增加,影响瓣膜置换术后患者临床转归。本研究通过 Meta 分析探讨经导管主动脉瓣置换(transcatheter aortic valve implantation, TAVI)术后 PPM 的危险因素。方法搜索 Medline、Cochrane图书馆、Scopus 数据库,选择有关 TAVI 术后 PPM 的研究。选择以是否发生 PPM 而分组比较的队列研究纳入Meta 分析。结果 PPM患者平均体表面积1.87±0.202平方米(m2),年龄78.3±7.78岁,左室射血分数41.0±14.1%,有效开瓣面积指数0.366±0.0922,相较无 PPM 患者,差异有统计学显著意义(P<0.05)。性别、体重指数、冠脉搭桥手术史、NYHA 分级、LogisticEuroscore,以及术前心脏彩超结果之主动脉瓣环大小、主动脉瓣跨瓣压等因素,两组间无显著差异(P>0.05)。结论较大的体表面积、较低

  9. Feasibility of small animal cranial irradiation with the microRT system

    Energy Technology Data Exchange (ETDEWEB)

    Kiehl, Erich L.; Stojadinovic, Strahinja; Malinowski, Kathleen T.; Limbrick, David; Jost, Sarah C.; Garbow, Joel R.; Rubin, Joshua B.; Deasy, Joseph O.; Khullar, Divya; Izaguirre, Enrique W.; Parikh, Parag J.; Low, Daniel A.; Hope, Andrew J. [Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Virginia Commonwealth University School of Medicine, Richmond, Virginia 23298 (United States); Washington University School of Medicine, St. Louis, Missouri 63110 (United States); Princess Margaret Hospital, Toronto, Ontario M5G 2M9 (Canada)


    Purpose: To develop and validate methods for small-animal CNS radiotherapy using the microRT system. Materials and Methods: A custom head immobilizer was designed and built to integrate with a pre-existing microRT animal couch. The Delrin couch-immobilizer assembly, compatible with multiple imaging modalities (CT, microCT, microMR, microPET, microSPECT, optical), was first imaged via CT in order to verify the safety and reproducibility of the immobilization method. Once verified, the subject animals were CT-scanned while positioned within the couch-immobilizer assembly for treatment planning purposes. The resultant images were then imported into CERR, an in-house-developed research treatment planning system, and registered to the microRTP treatment planning space using rigid registration. The targeted brain was then contoured and conformal radiotherapy plans were constructed for two separate studies: (1) a whole-brain irradiation comprised of two lateral beams at the 90 degree sign and 270 degree sign microRT treatment positions and (2) a hemispheric (left-brain) irradiation comprised of a single A-P vertex beam at the 0 degree sign microRT treatment position. During treatment, subject animals (n=48) were positioned to the CERR-generated treatment coordinates using the three-axis microRT motor positioning system and were irradiated using a clinical Ir-192 high-dose-rate remote after-loading system. The radiation treatment course consisted of 5 Gy fractions, 3 days per week. 90% of the subjects received a total dose of 30 Gy and 10% received a dose of 60 Gy. Results: Image analysis verified the safety and reproducibility of the immobilizer. CT scans generated from repeated reloading and repositioning of the same subject animal in the couch-immobilizer assembly were fused to a baseline CT. The resultant analysis revealed a 0.09 mm average, center-of-mass translocation and negligible volumetric error in the contoured, murine brain. The experimental use of the head

  10. Beware the Medical-Industrial Complex. (United States)

    Stevens; Glatstein


    biased data, if any at all). For radiation therapy, the 20th century has largely represented progress by creating larger, higher energy machines for treatment. Now, with the 21st century on the horizon, x-ray treatment parameters have probably been optimized over the past 10 years or so. We see no obvious advantage in an x-ray beam beyond about 18 MeV, and none for electrons beyond 20-25 MeV. Exotic particles such as protons, neutrons, and negative pions, though expensive and difficult to deliver, have not yielded yet significant gains in either local control or survival. A variety of new afterloading machines, such as pulsed high dose rate machines, have also been developed with no clear biologic advantage over more standard remote afterloaders. Thus, new equipment will be exploiting issues of convenience, efficiency, and increased throughput (translate: economic improvement, not biological superiority). Today's technology is vastly ahead of our biologic understanding of malignant cells. Our true challenge for the 21st century is to understand the biology of malignant cells and to bring our technology to bear on the biological aspects of cancer. To improve results, cellular manipulations of some sort will probably be necessary. Perhaps these will be mediated through gene therapy, although the manipulation of some genes, to the exclusion of all others, in only tumor cells and in all tumor cells may be a biological challenge beyond our limitations. One is reminded of another time, a decade or two ago, when some tumor immunologists were predicting monoclonal antibodies would soon replace other modalities. Eventually, over time, the immunologists began to appreciate the enormous adaptability that cancer cells possess; the cells are much more than passive receptacles of antigens simply waiting to be destroyed by antibodies. Drugs which affect the function of specific oncogenes, such as the farnesyl transferase inhibitor effect on ras genes, are also quite promising. Clearly

  11. Selected Abstracts of the 1st Congress of joint European Neonatal Societies (jENS 2015; Budapest (Hungary; September 16-20, 2015; Session “Circulation, O2 Transport and Haematology”

    Directory of Open Access Journals (Sweden)

    Various Authors



  12. Anesthesia management of modified extended Morrow procedure in treating hypertrophic obstructive car-diomyopathy%改良扩大 Morrow 手术的麻醉处理

    Institute of Scientific and Technical Information of China (English)

    田鹏声; 于钦军; 王水云; 陈雷


    Objective To summarize the anesthesia management and surgical characteristic of modified extended Morrow procedure in treating hypertrophic obstructive cardiomyopathy (HOCM). Methods This retrospective study was conducted in 139 patients (male 83 and female 56)aged from 1 1 to 66 years.They underwent general anesthesia by high dose intravenous fentanyl or sufentanyl combined with propofol infusion and low concentration sevoflurane inhalation.The surgeons chose ap-propriate surgical procedures,including modified extended Morrow procedure,or combined with mi-tral valve repair (replacement)and coronary artery bypass grafting,etc.All patients received intraop-erative transesophageal echocardiography (TEE ) or epicardial echocardiography monitoring. Results There was no death case in hospital.All patients were hemodynamically stable and there were no malignant adverse events such as ventricular fibrillation during perioperative period.70 (50.4%)of patients automatically recovered to cardiac rhythm after aortic unclamping,and 1 1 (7.9%)of patients needed temporary pacemaker due to atrioventricular block.Cardiopulmonary by-pass (CPB)were weaned off successfully without positive inotropic drugs in 103(74.1%)of patients, while others 36(25.9%)needed low dose dopamine,epinephrine or norepinephrine to maintain hemo-dynamics stable.The CPB time was (142 ± 5 1 )min and the time of aortic clamping was (96 ± 37 ) min.Blood protection was used in all patients and 129 (92.8%)of the patients didn’t receive any blood product.Conclusion Modified extended Morrow procedure was a safe and effective surgical pro-cedure for treatment of HOCM.Experienced teamwork was essential to achieve satisfactory clinical results.The key points of anesthesia management were administration of appropriate preoperative drugs,maintaining adequate anesthesia depth,appropriate preload and afterload,heart rate and rhythm.Intraoperative TEE monitoring was the golden standard for guiding and evaluating the

  13. Survey of protection level of radiation equipment room in thirty-three medical units in East China%华东地区33家医疗单位放射诊疗设备机房防护水平调查

    Institute of Scientific and Technical Information of China (English)

    赵国良; 郑亦军; 李勇; 周刚; 朱乐明; 毛树印; 杨龙


    Objective The rapid development of radiation equipment has put forward higher requirements for protective facil -ities.The aim of this study was to research the radiation protection status of treatment equipment room in thirty -three medical units from East China area , and to put forward corresponding countermeasures to improve the level of radiation protection . Methods The li-cense and archival of X-ray machine, CT, gamma knife, accelerator, after loading therapy machine were surveyed in the thirty-three medical units .The engine room size , wall thickness , lead equivalent of protection doors , and leakage level of equipment were detec-ted.All the data were evaluated and analyzed on the basis of the corresponding national standards . Results ①The inspection pass rates of radiation treatment equipments in the first class hospitals were afterloader (100%), X-ray apparatus(99%), gastrointestinal machine(98%), CT(98%), medical processing accelerator (98%), gamma knife(97%), DSA(94%), PET-CT(94%), ECT (90%), dental engine(84%)and molybdenum target drone (84%).The inspection pass rates of radiation treatment equipments in other class hospitals were medical processing accelerator (100%), X-ray apparatus(91%), CT(89%), gastrointestinal machine (80%), DSA(80%) and (80%) gamma knife.②The qualified rates of the leakage radiation levels of radiation therapy , diagnostic radiology and nuclear medicine were 100%, 99% and 97%. Conclusion The radiation protection of treatment equipments and facilities in thirty-three medical units from East China area needs to be strengthened . We should strengthen supervision , implement the rules and regulations , strictly perform the regulation of radiation protection evalua-tion, and strengthen the training of radiation protection regulations and skills .%目的:放射诊疗设备的迅速发展对防护设施提出了更高的要求,文中通过调查放射诊疗设备机房防护现状,提出相应对策,从而提高放射

  14. Endostatin improves the effect of radiotherapy in the treatment of squamous carcinoma of the uterine cervix%重组人血管内皮抑制素促进子宫颈鳞状细胞癌放疗效果的临床观察

    Institute of Scientific and Technical Information of China (English)

    刘晨; 杨蓉; 张凡; 陈江平


    Objective: To study the clinical efficacy of the combination of radiotherapy and endostatin injection in the treatment of moderate and advanced squamous carcinoma of the uterine cervix. Methods: Sixty patients with moderate and advanced cervical cancer were randomized divided into two groups; experiment group (n =30, treated with endostatin plus radiotherapy) and control group (n = 30, treated with radiotherapy alone). The radiotherapy in all patients was extracorporeal irradiation and intracavitary afterloading therapy. Endostatin (7. 5mg/m2 · d) was intravenously given for consecutive 14 days, followed by a 7 - day interval of rest, as a treatment cycle. The tumor vascular imaging parameters were detected by CT scan before treatment and 1,2,3,4 weeks after treatment, respectively, to assess the short - term efficacy of the treatment. Results : (1) In the experiment group, the degree of tumor vascular tortuosity and swelling was reduced, and the distribution of tumor vasculum was more evenly, showing different degrees of normalization, which was more evident at the first week after treatment. The tissue blood flow, blood volume, and mean transit time after treatment were significantly greater than those before treatment ( P 0.05). (2) In the control group, the tumor vascular morphology and distribution pattern had apparent changes after treatment, and the tissue blood flow, tissue blood volume, and mean transit time after treatment were significantly higher than those before treatment (P < 0.05 ). But the degree of these changes was significant lower than that of experiment group ( P < 0. 05 ). (3) There was a significant difference in the 5 - year survival rate, recurrence rate and progression - free survival rate, respectively, between two groups (P <0.05) , with the better efficacy in experiment group. Conclusion; The radiotherapy is a positive means for the treatment of moderate and advanced cervical cancer, and endostatin injection could improve the effect

  15. 3D打印技术在CT引导宫颈癌术后阴道残端肿瘤近距离治疗中应用%Application of 3D printing technology in brachytherapy for vaginal stump tumor after CT-guided cervical carcinoma surgery

    Institute of Scientific and Technical Information of China (English)

    于浪; 连欣; 晏俊芳; 罗春丽; 何蕾; 张悦; 王冠群; 李洪明; 杨波


    and organs at risk and calculate dose distribution.Results The individualized vaginal source applicator manufactured by 3D printing technology fitted well to the target volume,and the curvature of the catheters was greater than 1 cm,so that the radioactive source could pass successfully.The inserted catheters were cut,and the total operative length of the radioactive source was set to be 1 280 mm,which helped to realize the accurate connection between the individualized source applicator and the afterloader.At the same time when the prescribed dose was reached in the lesion,the bladder and rectal D2cm3 Was 320.4 cGy and 331.5 cGy,respectively,which did not exceed the dose limits.Conclusions The individualized source application manufactured by 3D printing technology is applicable to the treatment of patients with vaginal stump stenosis and regular solid tumor after cervical carcinoma surgery,and its clinical effect and adverse effects await further investigation.

  16. 新生儿先天性心脏病术后血液动力学的临床研究%Evaluation on the early hemodynamic changes after cardiac surgery for congenital heart diseases in neonates

    Institute of Scientific and Technical Information of China (English)

    仇黎生; 刘锦纷; 朱丽敏; 徐卓明


    malformation and longer cardiopulmonary bypass. The patients with significantly high arterial blood lactate levels during the first 6-12 hours postoperatively had poor outcome, lactate levels were higher than 10 mmol/L and SvO_2 less than 50% in neonates who developed multiple organ system failure. One young infant died of sudden arrhythmia after surgical treatment, whose death may be related the surgical procedure itself with pulmonary artery banding and blalock-taussig shunt leading to increased preload and afterload of the heart.Conclusions Elevated serum lactate level postoperatively may reflect intraoperative tissue hypoperfusion.Serial blood lactate level measurements may be an accurate predictor of clinical outcomes in children after podiatric open heart surgery. Mixed venous oxygen saturation changes more rapidly than other standard hemedynamic variables. The highter mortality of neonates with congenital heart disease is related to the malformation complexity itself and illness severity.%目的 通过测定心指数(CI)、血清乳酸浓度(Lac)、混合静脉血氧饱和度(SvO2)等指标,评估新生儿在经过体外循环术后的早期血液动力学状况.方法 2007年1月至11月,80例患儿作心脏术后48 h的血液动力学评估,包括新生儿组47例,年龄3~29 d,体重2.6~4.2 kg;婴儿组33例,年龄30~180 d,体重3.1~6 kg.并初步讨论新生儿心脏术后较高死亡率原因.结果 术后存活患儿两组比较中,新生儿组CI值[(2.01±0.35)L/(min·m~2)]<婴儿组[(2.26±0.39)L/(min·m~2)],术后2、6 h两组CI均值差异有统计学意义(P<0.05);新生儿组脉压<婴儿组,CI与新生儿组脉压的相关性有统计学意义;心率155次/min是心输出量的适宜心率;新生儿组血清Lac婴儿组,术后12 h两组差异有统计学意义;新生儿存活患儿的术后SvO_2均60%,SvO_2两组间均值差异无统计学意义;CI与SvO_2相关性有统计学意义(P<0.05),与血清Lac相关性无统计学意义.新生儿4

  17. Causas incomuns de instabilidade hemodinâmica durante revascularização miocárdica sem circulação extracorpórea Causas poco comunes de inestabilidad hemodinámica durante la revascularización miocárdica sin circulación extracorpórea Uncommon causes of hemodynamic instability during myocardial revascularization without cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Luciana Moraes dos Santos


    difficult to wean those patients off CB. Intraoperative control demands strict hemodynamic adjustment, as well as partial clamping of the aorta to minimize hemodynamic changes. The objective of this study was to report two cases of hemodynamic instability during MR without CB after partial clamping of the aorta. CASE REPORT: The first case is a female patient, whose aortic diameter was slightly reduced (2.8 cm; the second case refers to a patient with left ventricular ejection fraction (LVEF of 24% on the echocardiogram. In both cases, significant hypotension and increase in pulmonary blood pressure were observed immediately after clamping of the aorta. The surgical teams were informed of the problem, and in both cases the hemodynamic instability was reverted after unclamping of the aorta. Afterwards, smaller areas of the aorta were clamped and proximal anastomoses were performed without intercurrence. CONCLUSIONS: Although cardiac manipulation and changes in ventricular preload represent the most common causes of hemodynamic instability during MR without CB, in the cases presented here, hypotension and pulmonary hypertension were most likely secondary to a reduction in cardiac output due to the increase in afterload in patients with a relatively small aortic diameter or ventricular dysfunction even with partial clamping. Adequate intraoperative monitoring and immediate correction of the hemodynamic changes can minimize surgical morbidity and mortality.

  18. Individualized treatment prevents patient-prosthesis mismatch after aortic valve replacement with small aortic annulus%个体化治疗预防小主动脉瓣环瓣膜置换后瓣膜与患者的不匹配

    Institute of Scientific and Technical Information of China (English)

    韩劲松; 王辉山; 尹宗涛; 王婷婷; 韩宏光; 宋恒昌; 金岩


    BACKGROUND:It is so difficult to have aortic valve replacement with smal aortic annulus. Improper treatment may lead to patients with valvular mismatch phenomenon, and thus make left ventricular outflow tract obstruction, increase transvalvular pressures, cause cardiac hypertrophy secondary to increased left ventricular afterload and even congestive heart failure. OBJECTIVE:To summarize the treatment strategy for preventing valvular mismatch phenomenon caused by smal aortic annulus after aortic valve replacement. METHODS:Eighty-five patients with smal aortic annulus underwent aortic valve replacement surgery. 19 mm SJM Regent valve was applied to the patients with orifice diameter>17 ≤ 19 mm;to the adult patients with orifice diameter ≤ 17 mm, we performed bovine pericardial patch enlargement of the smal aortic annulus and valve replacement using 19 mm SJM Regent valve. For those with orifice diameter>19 ≤ 21 mm, we selected 21 mm Hancock II ultra biological valve for valve replacement. Effective orifice area index, left ventricular mass index, inter-ventricular septal thickness, left ventricular wal thickness, trans-valvular peak velocity, the pressure difference across the valve and trans-valvular mean pressure were measured through echocardiography. After discharge, patients were fol owed up in out-patient clinic and evaluated regularly by echocardiography. RESULTS AND CONCLUSION:There were no early deaths after operation and al cases were cured and discharged. Fol ow-up time was between 6 months and 3 years. The main complications included low cardiac output syndrome in two cases, reoperation due to bleeding in one case, and ventilator dependence in two cases. No cases occurred in cerebral complications such as cerebral hemorrhage or cerebral thrombosis, and no valvular dysfunction or card flap appeared. There was no bovine pericardium tearing, thrombosis, calcification, tumor-like bulge, infection or immune reactions. A total of 81 cases were fol owed

  19. Anestesia para o recém-nascido submetido a cirurgia cardíaca com circulação extracorpórea Anestesia para el recién nacido sometido a cirugía cardiaca con circulación extracorpórea Anesthesia for the newborn submitted to cardiac surgery with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Sérgio Bernardo Tenório


    ítrico o los inhibidores de la fosfodiesterasa. CONCLUSIONES: El anestesista tiene papel preponderante en el ajuste de la homeostasia durante el período peri-operatorio. Conocimientos sobre el tipo de lesión cardiaca, la corrección a ser realizada, la respuesta del organismo a la CEC pueden ser útiles en el manoseo de estos niños.BACKGROUND AND OBJECTIVES: Congenital heart diseases affect 0.8% of liveborn infants and many need neonatal surgical correction. Cardiac surgery with cardiopulmonary bypass (CPB in this age is associated to higher risk of complications related to child's functional immaturity, lack of CPB equipment fully compatible with neonate (NN size and technical difficulties to correct cardiac defects. This article aimed at describing aspects related to anesthetic technique, CPB and their effects on NN. CONTENTS: High fentanyl or sufentanil doses promote adequate anesthesia without interfering with cardiocirculatory stability. Opioids residual respiratory depression is not a problem for these patients because most of them will need immediate postoperative respiratory assistance. CPB may be followed by heart manipulation-induced hypotension and/or bleeding. Inadequate venous and aortic cannula position may lead to severe complications, such as insufficient brain flow or difficult venous drainage. Deep hypothermia and total circulatory arrest are common during CPB. Hypothermia changes blood viscosity, which is treated with hemodilution and has implications on pH correction (alpha-stat versus pH stat. Low cardiac output is common during CPB weaning and adjustments in one or all its components (preload, contractility, afterload and heart rate may be necessary. In addition to classic drugs, such as epinephrine and dopamine, other substances may be needed, such as aprotinin, nitric oxide or phosphodiesterase inhibitors. CONCLUSIONS: Anesthesiologists play a major role in adjusting perioperative homeostasis. Understanding the type of cardiac disease, the

  20. 脉搏指示连续心排血量监测技术救治重症胰腺炎并发急性呼吸窘迫综合征患儿二例%Pulse indicator continuous cardiac output measurement-guided treatment aids two pediatric patients with severe acute pancreatitis complicated with acute respiratory distress syndrome

    Institute of Scientific and Technical Information of China (English)

    颜卫源; 王丽杰


    PICU,EVLWI dropped to 6 ml/kg,GEDVI dropped to 370 mL/m2,and the oxygenation index increased to 180 mmHg.On day 8,the patient was successfully weaned from the ventilator.However,on day 9,the patient reverted to mechanical ventilation due to secondary infection.On day 30,the patient was discharged for voluntarily giving up treatment.Late follow-up results showed that the patient was dead one day after giving up treatment.Case 2 was admitted due to SAP induced by overeating one day before admission.On day 2,the patient showed dyspnea and oxygen saturation decreased to 80%.We applied mechanical ventilation,CVVHDF to remove inflammatory mediators and PiCCO to guide fluid management.According to the initial data of PiCCO,EVLWI was 9 m[/kg,GEDVI was 519 ml/m2,the oxygenation index was 298 mmHg,the bedside chest X-ray showed decreased permeability and PEEP was adjusted to 5 cmH2O,suggesting the existence of ARDS.During treatment,the dehydration speed of CVVHDF was set at 50 ml/h to maintain the balance of fluid input and output.Two hours after PiCCO monitoring,the oxygenation index decreased to 140 mmHg,GEDVI 481 ml/m2,EVLWI 9 ml/kg,thus the dehydration speed of CVVHDF was increased (up to 100 ml/h).On day 4 in the PICU,EVLWI was 9 ml/kg,GEDVI was 430 ml/m2,oxygenation index was 394 mmHg,and the bedside chest X-ray showed that permeability was higher.On day 5,the patient was transferred from PiCCO.On day 30,the patient recovered and was discharged.Conclusion PiCCO monitoring can provide real-time surveillance of cardiac function,cardiac preload and afterload,and extravascular lung water in pediatric patients with SAP combined with ARDS.These results are clinically significant for the rescue of critically ill patients with ARDS or shock.%目的 探讨脉搏指示连续心排血量监测(PiCCO)在指导儿童重症胰腺炎(SAP)并发急性呼吸窘迫综合征(ARDS)治疗中的作用.方法 对2例SAP合并ARDS患儿在综合治疗的同时进行PiCCO监测,根据心脏指

  1. Clinical study of rapid shallow breathing index as the switching point for sequential ventilation for patients with prolonged weaning after thoracolaparotomy%胸腹术后延迟撤机患者以浅快呼吸指数为切换点序贯通气治疗临床研究

    Institute of Scientific and Technical Information of China (English)

    丁欢; 周文艳; 王丽娟; 马希刚; 曹相原


    , pH, PaO2, PaCO2 and PaO2/FiO2;hemodynamic and microcirculation-related variables: HR, MAP, fluid balance, BNP and Lac;endocrine and metabolism variables : Hb, ALB and random serum cortisol (COR).The clinical features and the changes of the above-mentioned variables before and at the time of switching were compared between both groups.The independent sample t test was used for the single factor comparison and Mann-Whitney U test was applied to the non-normal distributions.The Fisher exact probability test was used for the single factor comparison of ranked data such as categorical variables.Results There were no significant differences in age, gender and severity of disease between two groups (P > 0.05);the successfully prolonged weaning group had longer duration of invasive mechanical ventilation and ICU stay compared with the refractory weaning group (P < 0.05).There were significant differences in cough severity, PaCO2, pH, HR and fluid balance between two groups before switching (P < 0.05).Compared with those before switching, in the refractory weaning group there were marked decrease in Lac (P < 0.05), obvious increase in cough severity, pH, Hb and ALB (P < 0.05), but there was no significant difference in COR (P > 0.05);while in the successfully delayed weaning group, there were significant decrease in CPIS, PaCO2, HR, MAP, BNP, fluid balance and Lac (P < 0.05), and cough severity, pH, ALB and COR showed an upward trend (P < 0.05).Conclusions The key of successful sequential ventilation is within the values of RSBI ranging from 80 to 120 times/ (min · L) during the initial SBT (60 min) selected as the switching point in patients with prolonged weaning after thoracolaparotomy.The major influencing factors for determining the ideal timing of switching include the matching status between respiratory endurance and respiratory work, the balance between myocardial strength and both cardiac preload and afterload, the severe disease associated with