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  • Outcomes from a Postgraduate Biomedical Technology Innovation Training Program: The First 12 Years of Stanford Biodesign ANNALS OF BIOMEDICAL ENGINEERING Brinton, T. J., Kurihara, C. Q., Camarillo, D. B., Pietzsch, J. B., Gorodsky, J., Zenios, S. A., Doshi, R., Shen, C., Kumar, U. N., Mairal, A., Watkins, J., Popp, R. L., Wang, P. J., Makower, J., Krummel, T. M., Yock, P. G. 2013; 41 (9): 1803-1810

    Abstract

    The Stanford Biodesign Program began in 2001 with a mission of helping to train leaders in biomedical technology innovation. A key feature of the program is a full-time postgraduate fellowship where multidisciplinary teams undergo a process of sourcing clinical needs, inventing solutions and planning for implementation of a business strategy. The program places a priority on needs identification, a formal process of selecting, researching and characterizing needs before beginning the process of inventing. Fellows and students from the program have gone on to careers that emphasize technology innovation across industry and academia. Biodesign trainees have started 26 companies within the program that have raised over $200 million and led to the creation of over 500 new jobs. More importantly, although most of these technologies are still at a very early stage, several projects have received regulatory approval and so far more than 150,000 patients have been treated by technologies invented by our trainees. This paper reviews the initial outcomes of the program and discusses lessons learned and future directions in terms of training priorities.

    View details for DOI 10.1007/s10439-013-0761-2

    View details for Web of Science ID 000323736800002

    View details for PubMedID 23404074

  • Troponin Messenger or Actor? JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 2013; 61 (6): 611-614

    Abstract

    Cardiac troponin (cTn) is a biomarker of myocardial damage. New generations of high-sensitivity assays find circulating cTn in virtually all subjects. Multiple studies in various populations and patient groups have found higher levels of cTn to be predictive of future heart failure. The author proposes that initial myocardial damage from various mechanisms may lead to anti-cTn antibodies that participate in ongoing myocardial damage that eventually results in heart failure.

    View details for DOI 10.1016/j.jacc.2012.11.024

    View details for Web of Science ID 000314660700003

    View details for PubMedID 23391193

  • Reply to Letter to Editor by Peng, et. al. Journal of the American College of Cardiology Popp, R. L. 2013

    View details for PubMedID 23542108

  • Assessment of left ventricular function by echocardiography: A technique in evolution JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY Picard, M. H., Popp, R. L., Weyman, A. E. 2008; 21 (1): 14-21

    Abstract

    One of the earliest applications of clinical echocardiography was the evaluation of left ventricular (LV) size and function. The accuracy of the determination of global and regional LV function with echocardiography has improved as the technology has matured. The following paper discusses the advances in LV function assessment starting with Inge Edler's original A-mode and M-mode observation moving through two dimensional echocardiographic methods to new three dimensional echocardiographic assessment and even new Doppler and speckle myocardial methods. During the evolution of ultrasonic assessment of LV function, each new method has overcome limitations of previous ones, resulting in better appreciation of the LV geometry and volume and improved accuracy and reproducibility for quantitation. As discussed in this report, many of the echocardiographic methods used today to assess LV systolic function were envisioned by Harvey Feigenbaum more than 25 years ago. The future will undoubtedly see a new method of clinical cardiology care but with continued evolution, echocardiographic quantitation of LV function should remain a vital part of patient care.

    View details for DOI 10.1016/j.echo.2007.11.007

    View details for Web of Science ID 000252359000004

    View details for PubMedID 18165124

  • Comparison of three-dimensional echocardiography to two-dimensional echocardiography and fluoroscopy for monitoring of endomyocardial biopsy AMERICAN JOURNAL OF CARDIOLOGY Amitai, M. E., Schnittger, I., Popp, R. L., Chow, J., Brown, P., Liang, D. H. 2007; 99 (6): 864-866

    Abstract

    Real-time 3-dimensional echocardiography (RT3DE) offers the rapid acquisition of quantitative and qualitative anatomic data without the use of geometric assumptions. This study was designed to test the feasibility and potential superiority of RT3DE versus 2-dimensional echocardiography (2DE) and standard fluoroscopy for monitoring endomyocardial biopsies (EMBs). Thirty-eight consecutive EMBs performed under fluoroscopic guidance in 26 patients were monitored using 2DE and RT3DE alternately. Two reviewers scored each biopsy pass for visualization of the tip of the bioptome and location of the actual biopsy. Overall image quality was noted as good or poor, and the effect of image quality on tip localization was analyzed. A total of 243 biopsy attempts were made during 38 EMBs. The location of the biopsy was determined in 74% of the biopsies monitored with RT3DE, whereas 2DE demonstrated the location with certainty in only 43% of the biopsies (p <0.0001). On a procedure-by-procedure comparison, RT3DE was found to show the bioptome tip better in 23 of 38 biopsies, compared with 1 of 38 for 2DE (p = 0.001). In 14 of 38 EMBs, neither method was clearly better. In conclusion, RT3DE improves the ability to see the location of the bioptome during EMB compared with 2DE and fluoroscopy.

    View details for DOI 10.1016/j.amjcard.2006.10.050

    View details for Web of Science ID 000245289200027

    View details for PubMedID 17350384

  • An outline for public registration of clinical trials evaluating medical devices JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L., Lorell, B. H., Stone, G. W., Laskey, W., Smith, J. J., Kaplan, A. V. 2006; 47 (8): 1518-1521

    Abstract

    Public registration of clinical trials is fundamentally important to the integrity of the medical device development process. In addition to fulfilling obligations to those study volunteers, a complete record of trial results provides the general public, clinical community, and medical device manufacturers with a more accurate understanding as to how a specific therapeutic should be used. Although the issues associated with public disclosure of clinical trials are similar to the pharmaceutical industries, the iterative nature of device development introduces differences in what type of information needs to be disclosed during development and commercialization. The Second Dartmouth Device Development Symposium (3D2) held in October 2004 brought together thought leaders representing many of the stakeholders associated with medical device development. This consensus document arising from the proceedings of the 3D2 is offered to provide background to these issues and recommend pathways to implementation of device trial registration.

    View details for DOI 10.1016/j.jacc.2005.09.079

    View details for Web of Science ID 000236819000002

    View details for PubMedID 16630985

  • Innovation, journal reviewers, and journal editors - The game is worth the candle JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 2005; 46 (7): 1360-1361

    View details for DOI 10.1016/j.jacc.2005.04.001

    View details for Web of Science ID 000232315900024

    View details for PubMedID 16198856

  • Conflict of interest for the physician-inventor using a device in human subjects AMERICAN HEART JOURNAL Popp, R. L. 2005; 149 (1): 1-3

    View details for DOI 10.1016/j.ahj.2004.06.005

    View details for Web of Science ID 000226387000001

    View details for PubMedID 15660027

  • The role of the American College of Cardiology in promoting and maintaining the delivery of quality cardiovascular care in the future JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Klocke, F. J., Douglas, P. S., Nissen, S. E., Popp, R. L. 2000; 35 (5): 99B-101B

    View details for Web of Science ID 000086316700019

    View details for PubMedID 10757375

  • The role of the American College of Cardiology in promoting and maintaining the delivery of quality cardiovascular care in the future JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Klocke, F. J., Douglas, P. S., Nissen, S. E., Popp, R. L. 2000; 35 (4): 1100-1102

    View details for Web of Science ID 000085917200035

    View details for PubMedID 10732914

  • Stress echocardiography results in context EUROPEAN HEART JOURNAL Popp, R. L. 1999; 20 (20): 1450-1451

    View details for Web of Science ID 000082752800006

    View details for PubMedID 10610323

  • President's page: A time for celebration JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 1998; 31 (4): 890-891
  • President's page: Looking back ... looking forward JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 1998; 31 (2): 483-484
  • President's page: ACC's strategic plan - A road map for the future JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 1998; 31 (1): 238-239
  • Task force 3: Guidelines for credentialling practicing physicians JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Beller, G. A., Winters, W. L., Carver, J. R., King, S. B., McCallister, B. D., Popp, R. L. 1997; 29 (6): 1148-1162
  • President's page: First, do no harm JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L. 1997; 29 (6): 1405-1406
  • A three-dimensional perspective EUROPEAN HEART JOURNAL Popp, R. L. 1996; 17 (10): 1456-1458

    View details for Web of Science ID A1996VL04100003

    View details for PubMedID 8909895

  • Coronary artery intimal thickening in the transplanted heart - An in vivo intracoronary ultrasound study of immunologic and metabolic risk factors TRANSPLANTATION Rickenbacher, P. R., Kemna, M. S., Pinto, F. J., Hunt, S. A., Alderman, E. L., Schroeder, J. S., Stinson, E. B., Popp, R. L., Chen, I., Reaven, G., Valantine, H. A. 1996; 61 (1): 46-53

    Abstract

    This study examined the hypothesis that immunologic factors are the major correlates of coronary artery intimal thickening and luminal stenosis. The study population included 116 adult heart transplant recipients with a mean age of 44.7 +/- 12.0 years (89 men and 27 women) undergoing annual coronary angiography and intracoronary ultrasound 3.4 +/- 2.7 (range, 1.0-14.6) years after transplantation. Mean intimal thickness was obtained from several distinct sites along the left anterior descending and/or left circumflex coronary artery by intracoronary ultrasound. Coronary artery stenosis defined by angiography was classified as mild (< 30% luminal stenosis), moderate (> or = 30-70% luminal stenosis), or severe (> 70% luminal stenosis or diffuse pruning of distal vessels). Prevalence of any transplant coronary artery disease (TxCAD) was 85% by intracoronary ultrasound and 15% by angiography. By multiple regression analysis, only average fasting plasma triglyceride level (P < 0.006) and average weight (P < 0.007) were significantly correlated with severity of intimal thickening (R = 0.54, P < 0.0001). Donor age (P < 0.006) and average fasting plasma triglyceride level (P < 0.009) were significantly correlated with stenosis by angiography. Correlation of multiple immunologic and metabolic factors with intimal thickness by univariate analysis suggests a multifactorial etiology for TxCAD. Among the multiple univariate correlates of TxCAD, higher fasting plasma triglyceride levels and body weight are the only independent correlates of TxCAD. The absence of acute rejection as an independent predictor of intimal thickening suggests that mechanisms beyond those mediating typical cellular rejection should be targeted for advancing our understanding of Tx-CAD.

    View details for Web of Science ID A1996TQ20100011

    View details for PubMedID 8560573

  • TASK-FORCE-2 - ACADEMIC HEALTH CENTERS JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY King, S. B., Frye, R. L., Fuster, V., Garson, A., Gay, W. A., Popp, R. L. 1994; 24 (2): 290-295

    View details for Web of Science ID A1994PH37600003

    View details for PubMedID 8034860

  • INTRAVASCULAR ULTRASOUND IMAGING OF CORONARY-ARTERIES - IS 3 LAYERS THE NORM CIRCULATION Fitzgerald, P. J., STGOAR, F. G., Connolly, A. J., Pinto, F. J., Billingham, M. E., Popp, R. L., Yock, P. G. 1992; 86 (1): 154-158

    Abstract

    The purpose of this study was to evaluate the significance of the three-layered appearance of coronary arteries in adolescence and adults from intravascular ultrasound scans and to correlate these observations with histopathology.Sixteen intact hearts were excised at autopsy from patients with no clinical history of coronary artery disease. The patients' ages ranged from 13 to 55 years. A 30-MHz ultrasound imaging catheter was used to obtain images throughout the epicardial coronary vasculature. A total of 72 image cross sections was marked by epivascular sutures, and the corresponding histological sections were examined. Ultrasound images were classified into two groups: images exhibiting three-layered appearance and images without distinct layering. Histological analysis revealed a significantly greater degree of intimal thickening in segments with three layers (243 +/- 105 microns) than in nonlayered segments (112 +/- 55 microns). Discriminant analysis of these data predicted the threshold between the two groups to be 178 microns. Measurements of medial thickness were not different between these two groups (235 +/- 61 versus 210 +/- 76 microns). In the nonlayered group, the average patient age was 27.1 +/- 8.5 years, whereas in the three-layered groups, the average age was 42.8 +/- 9.8 years.The intracoronary ultrasound image appearance of young, morphologically normal coronary artery walls is homogeneous without layering. A three-layered appearance suggests the presence of at least 178 microns of intimal thickening and is seen more frequently with advancing age.

    View details for Web of Science ID A1992JC45700018

    View details for PubMedID 1617768

  • TISSUE SIGNATURE - DISCUSSION-V AMERICAN JOURNAL OF CARDIOLOGY Feigenbaum, H., Kaul, S., Perez, J., Popp, R., SKORTON, D., Meltzer, R., Nanda, N., Gardin, J., Geiser, E. 1992; 69 (20): H117-H120
  • MILDLY DILATED CONGESTIVE CARDIOMYOPATHY - USE OF PROSPECTIVE DIAGNOSTIC-CRITERIA AND DESCRIPTION OF THE CLINICAL COURSE WITHOUT HEART-TRANSPLANTATION CIRCULATION Keren, A., Gottlieb, S., Tzivoni, D., Stern, S., YAROM, R., Billingham, M. E., Popp, R. L. 1990; 81 (2): 506-517

    Abstract

    Prognosis in classically described dilated congestive cardiomyopathy has been reported to be related to ventricular size. Mildly dilated congestive cardiomyopathy (MDCM) has been defined as end-stage heart failure of unknown etiology (New York Heart Association class IV, left ventricular ejection fraction less than 30%), occurring with neither typical hemodynamic signs of restrictive myopathy nor significant ventricular dilatation (less than 15% above normal range). The present study includes follow-up in 12 nontransplant patients. In the first 4 months after diagnosis, two patients improved and are living, and two showed cardiac dilation and clinical deterioration and died. Six of the remaining eight with persistent MDCM died (four with intractable heart failure and two, sudden deaths) without change in ventricular size before death, despite medical therapy over 20 +/- 8 months. Eight comparable transplanted patients with persistent MDCM demonstrated improved total survival by life table analysis (p less than 0.05). A family history of congestive cardiomyopathy was found in nine of 16 patients (56%) with persistent MDCM. Nontransplant patients were older (p less than 0.02), but other findings were similar in the two groups. Endomyocardial biopsies available in 14 of 16 cases showed little or no myofibrillar loss in spite of severe hemodynamic impairment. The degree of myofibrillar loss did not correlate with hemodynamic parameters but showed good correlation with left ventricular size, that is, five of six patients with no myofibrillar loss had normal ventricular size, whereas all eight patients with mild myofibrillar loss had mild cardiomegaly (p less than 0.002). Our current experience suggests a somewhat variable but negative prognosis after prospective diagnosis of MDCM, with poor survival in patients with persistence of the original diagnostic features during follow-up. Preservation of heart size in MDCM is probably related to lack of significant myofibrillar loss. Thus, irrespective of heart size or myofibrillar preservation on biopsy, heart transplantation should be strongly considered in MDCM if signs of severe cardiac dysfunction persist despite therapy.

    View details for Web of Science ID A1990CM83600012

    View details for PubMedID 2297858

  • Flow velocity acceleration in the left ventricle: a useful Doppler echocardiographic sign of hemodynamically significant mitral regurgitation. Journal of the American Society of Echocardiography Appleton, C. P., Hatle, L. K., Nellessen, U., Schnittger, I., Popp, R. L. 1990; 3 (1): 35-45

    Abstract

    Doppler echocardiography is a sensitive method to detect mitral regurgitation in patients with both native and prosthetic valves. However, estimates of the amount of mitral regurgitation remain semiquantitative, and even severe mitral regurgitation may be underestimated in the presence of markedly eccentric regurgitant jets or acoustic shadowing of the left atrium by mitral or aortic prostheses. This report describes the Doppler findings in 10 patients with severe native valve mitral regurgitation (angiographic grade III or IV) and in 15 patients with severe bioprosthetic mitral regurgitation that required valve replacement. An increase in peak mitral flow velocity above normal values was seen in eight of 10 patients with severe native valve mitral regurgitation (greater than or equal to 130 cm per second) and 11 of 15 patients with severe prosthetic valve mitral regurgitation (greater than or equal to 210 cm per second). One of 10 patients with a native valve and four of 15 patients with a bioprosthetic valve appeared to have only a localized left atrial systolic flow disturbance, incorrectly suggesting that the mitral regurgitation was mild. However, in all patients with severe mitral regurgitation, a low velocity (less than 100 cm per second) flow signal could be recorded in the left ventricle that was directed toward the mitral valve in systole. This flow signal showed a gradual increase in velocity as the sample volume was moved toward the mitral valve, with an abrupt further increase on entry into the left atrium. This signal was continuous with antegrade mitral flow and had the same orientation as mitral regurgitation recorded by continuous wave technique from the apex. A similar flow signal was not recorded in the left ventricle of any individual in a control group of 30 patients who had no mitral regurgitation or who had angiographic grade I or II mitral regurgitation. These findings suggest that acceleration of left ventricle flow toward the mitral valve in systole is only recorded when there is hemodynamically significant mitral regurgitation that is approximately equal to angiographic grade III or IV. Recognition of this Doppler finding may help in the estimation of mitral regurgitation severity, especially in difficult diagnostic situations.

    View details for PubMedID 2310590

  • TRANSESOPHAGEAL ECHOCARDIOGRAPHY - AN INTRODUCTION FOR ULTRASONOGRAPHERS JOURNAL OF DIAGNOSTIC MEDICAL SONOGRAPHY Tye, T. L., Nellessen, U., Schnittger, I., Popp, R. 1989; 5 (6): 316-321
  • THE HEMODYNAMIC-EFFECTS OF REPEATED BEDREST EXPOSURE AVIATION SPACE AND ENVIRONMENTAL MEDICINE Sandler, H., Popp, R. L., HARRISON, D. C. 1988; 59 (11): 1047-1054

    Abstract

    Hemodynamic changes were measured during stepwise exposure to lower-body negative pressure (LBNP) (5 min, -20, -30, and -40 mm Hg) in a group of seven physically active subjects before and after consecutive exposure to three 2-week bed rest periods. Bed rest exposures were separated by 3-week periods of ambulatory recovery. Dynamic exercise (68% max O2, 30 min each day) and isometric exercise (21% max leg extension, 30 min each day) performed during bed rest and reambulation failed to prevent deconditioning or accelerate the recovery process between bed rest exposures. Heart rate (HR) and end-diastolic volume index (EDVI) proved to be parameters showing greatest changes during LBNP. Heart rate increases at -40 mm Hg LBNP (compared to respective pre-LBNP levels) were 13.3%, 35.1%, and 51.0% for each of the pre-bed rest exposures, while respective changes after bed rest were 57.8%, 57.2%, and 75.5%. The significantly elevated HR responses during subsequent pre-bed rest (control) periods indicated incomplete recovery despite mild exercise and ambulation. Comparison of EDVI and HR revealed a similar linear regression relationship during LBNP before and after bed rest so that EDVI = 112.5-0.85 x HR, r = -0.97. We conclude from these findings that cardiovascular deconditioning for physically active individuals involves factors other than simple loss of plasma volume, requires at least 3 weeks or longer to return to the pre-bed rest state, and is not counteracted by the levels of aerobic and/or isometric exercise used in the present study.

    View details for Web of Science ID A1988Q841400006

    View details for PubMedID 3202785

  • TRANS-ESOPHAGEAL DOPPLER ECHOCARDIOGRAPHY MAYO CLINIC PROCEEDINGS Schnittger, I., Popp, R. L. 1988; 63 (7): 726-728

    View details for Web of Science ID A1988P341300007

    View details for PubMedID 3386312

  • METHODS FOR ESTIMATION OF STATISTICAL PROPERTIES OF ENVELOPES OF ULTRASONIC ECHOES FROM MYOCARDIUM IEEE TRANSACTIONS ON MEDICAL IMAGING Wear, K. A., Popp, R. L. 1987; 6 (4): 281-291

    Abstract

    Several investigators have characterized various forms of heart disease from the statistical properties of envelopes of ultrasonic echos from myocardium. In particular, the mean-to-standard deviation ratio (MSR), skewness, and kurtosis of the envelope probability density function have been used for the detection of myocardial ischemia, infarction, reperfusion, and hypertrophy. In this paper, the effects of phenomena other than tissue acoustic properties upon estimates of statistical parameters are investigated. These include system characteristics (center frequency, bandwidth, beam width, etc.), sample volume dimensions, and tissue velocity. In myocardium, relatively small amounts of tissue are available for interrogation. It is shown that, under these limited data acquisition conditions, substantial systematic biases in the estimates of statistical parameters may occur. Analytic forms for errors in the envelope variance estimate are derived. Estimation of the envelope mean, variance, MSR, skewness, and kurtosis is investigated experimentally, using a commercial medical ultrasound scanner and a tissue-mimicking phantom.

    View details for Web of Science ID A1987L191800001

    View details for PubMedID 18244035

  • Changes in Doppler echocardiographic indexes of left ventricular function as potential markers of acute cardiac rejection. Circulation Valantine, H. A., Fowler, M. B., Hunt, S. A., NAASZ, C., Hatle, L. K., Billingham, M. E., Stinson, E. B., Popp, R. L. 1987; 76 (5): V86-92

    Abstract

    Changes in left ventricular filling and ejection as potential markers of cardiac allograft rejection were evaluated by serial Doppler echocardiography performed in 23 normal volunteers and within 24 hr of endomyocardial biopsy in 22 patients aged 14 to 53 years (mean 37). Peak aortic velocity, left ventricular ejection time index (ETI), isovolumic relaxation time (IVRT), mitral valve pressure half-time (PHT), peak early mitral flow velocity (M1), and velocity following donor atrial systole (M2) were measured without prior knowledge of endomyocardial biopsy findings. Biopsy specimens were graded histologically as: no rejection, mild rejection (cellular infiltrate), and moderate rejection (myocyte necrosis). A total of 120 biopsy-correlated Doppler echocardiographic studies were performed during 16 weeks after cardiac transplantation. Heart rate and mean arterial pressure were significantly higher in transplant recipients than in normal subjects. IVRT and PHT were significantly longer, while M1 and M2 were similar. Peak aortic velocity was higher in normal subjects than in transplant recipients, while ejection time was similar. Rejection of increasing severity was associated with a progressive shortening of IVRT and PHT and with an increase in M1 (p less than .0005 for all comparisons). Peak aortic velocity and ejection time index did not change significantly with rejection. These data indicate that acute cardiac rejection is accompanied by alteration in left ventricular filling dynamics detectable by Doppler echocardiography, without measureable changes in systolic function. These changes may provide noninvasive markers for surveillance of rejection.

    View details for PubMedID 3311461

  • CHANGES IN DOPPLER ECHOCARDIOGRAPHIC INDEXES OF LEFT-VENTRICULAR FUNCTION AS POTENTIAL MARKERS OF ACUTE CARDIAC REJECTION CIRCULATION Valantine, H. A., Fowler, M. B., Hunt, S. A., NAASZ, C., Hatle, L. K., Billingham, M. E., Stinson, E. B., Popp, R. L. 1987; 76 (5): 86-92
  • INTRAVENTRICULAR FLOW DURING ISOVOLUMIC RELAXATION - DESCRIPTION AND CHARACTERIZATION BY DOPPLER ECHOCARDIOGRAPHY JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Sasson, Z., Hatle, L., Appleton, C. P., Jewett, M., Alderman, E. L., Popp, R. L. 1987; 10 (3): 539-546

    Abstract

    This study describes the characteristics of a prominent Doppler flow velocity signal representing intraventricular flow during left ventricular isovolumic relaxation. The flow during the isovolumic relaxation period was demonstrated in 60 subjects, including 7 with a normal heart, 26 with hypertrophic cardiomyopathy, 10 with aortic valve disease, 9 with a transplanted heart and 8 others. All had normal to hyperdynamic left ventricular systolic function with some degree of cavity obliteration as seen in the apical two-dimensional echocardiographic views. In contrast, this isovolumic relaxation period flow could not be demonstrated in the absence of cavity obliteration in any of 20 patients with either normal or diminished left ventricular systolic function. Isovolumic relaxation period flow was best recorded from the apical transducer position and was directed toward the apex in all patients. By pulsed wave, and with two-dimensional Doppler ultrasound, the isovolumic relaxation period flow originated within a narrow area in the medial portion of the left ventricle along the middle or basal segments of the interventricular septum, but was recorded over a larger area toward the apex. The peak isovolumic relaxation period flow velocity was recorded just basal to the area of cavity obliteration, usually at the level of the papillary muscles, and ranged from 0.4 to 2.3 m/s (mean of 1.0 m/s). This isovolumic relaxation period flow started with aortic valve closure and, in 50 of the 60 patients, it lasted throughout isovolumic relaxation until mitral valve opening. In the other 10 patients (all with hypertrophic cardiomyopathy), it lasted for only a part (mean 63%) of this period.(ABSTRACT TRUNCATED AT 250 WORDS)

    View details for Web of Science ID A1987K104300009

    View details for PubMedID 3624661

  • GUIDELINES FOR OPTIMAL PHYSICIAN TRAINING IN ECHOCARDIOGRAPHY - RECOMMENDATIONS OF THE AMERICAN-SOCIETY-OF-ECHOCARDIOGRAPHY COMMITTEE FOR PHYSICIAN TRAINING IN ECHOCARDIOGRAPHY AMERICAN JOURNAL OF CARDIOLOGY Pearlman, A. S., Gardin, J. M., Martin, R. P., Parisi, A. F., Popp, R. L., Quinones, M. A., Stevenson, J. G. 1987; 60 (1): 158-163

    Abstract

    Over the past few years, the clinical use of echocardiography has continued to expand. Echocardiographic techniques are used widely to define normal and abnormal cardiac anatomy, evaluate cardiac chamber sizes and dynamics, assess valvular and pericardial diseases, detect intracavitary masses, measure pressure gradients across discrete stenoses, determine flow volumes, detect and assess the severity of valvular regurgitation, demonstrate and quantitate intracardiac shunts, and measure the timing of cardiac events. These and related applications have led to the increasing use of echocardiography in the diagnostic evaluation of many cardiac disorders. Echocardiography requires considerable theoretical knowledge, technical skill and practical experience to be used in an optimal manner. Previous publications have suggested guidelines for physician training in the techniques of M-mode and 2-dimensional echocardiography. The clinical applications of echocardiography continue to grow, however, and Doppler techniques for evaluating blood flow have become an established component of the echocardiographic evaluation of many disorders. This article presents the current recommendations of the American Society of Echocardiography as to the background knowledge, the nature and amount of practical experience, and the type of training site that are optimal for the training of physicians who take responsibility for the conduct and interpretation of echocardiographic studies.

    View details for Web of Science ID A1987J057400033

    View details for PubMedID 3604931

  • WHEN SHOULD DOPPLER-DETERMINED VALVE AREA BE BETTER THAN THE GORLIN FORMULA - VARIATION IN HYDRAULIC CONSTANTS IN LOW FLOW STATES JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Segal, J., Lerner, D. J., Miller, D. C., Mitchell, R. S., Alderman, E. A., Popp, R. L. 1987; 9 (6): 1294-1305

    Abstract

    In low flow states, underestimation errors occur when the Gorlin formula is used to calculate valve area. A model of valvular stenosis designed to examine changes in the hydraulic discharge coefficient (Cd) and coefficient of orifice contraction (Cc) may explain these errors. Unsteady flow was examined in a pulsatile pump model and in a dog model. Valve areas were calculated from pressure and flow data using: a modified form of the Gorlin formula (assuming constant values for Cd and Cc) and a corrected formula (with values of Cd and Cc obtained from steady state data). Valve area was also calculated using the continuity equation with velocity and flow data (constant Cc). Flow velocities were measured using a newly designed ultrasound Doppler catheter capable of resolving flow velocities of up to 5.5 m/s. Both the corrected formula and continuity equation were highly predictive of actual valve area (r = 0.99, slope or M = 0.96 and r = 0.99, M = 1.06, respectively). The modified Gorlin equation was less accurate and tended to underestimate valve areas (r = 0.87, M = 0.83). This underestimation was most notable at low rates of flow (Gorlin: r = 0.94, M = 0.53; continuity: r = 0.93, M = 0.81 and r = 0.94, M = 0.89, respectively) more accurately than the modified Gorlin formula (r = 0.69, M = 0.49). In patients with low cardiac output, hemodynamic formulas, such as the Gorlin formula, which assume a constant value for the hydraulic discharge coefficient (Cd), may be less accurate than formulas using either a corrected value of Cd or Doppler-determined flow velocity and mean systolic flow.

    View details for Web of Science ID A1987H646300013

    View details for PubMedID 3294968

  • THEORETICAL-ANALYSIS OF A TECHNIQUE FOR THE CHARACTERIZATION OF MYOCARDIUM CONTRACTION BASED UPON TEMPORAL CORRELATION OF ULTRASONIC ECHOES IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Wear, K. A., Popp, R. L. 1987; 34 (3): 368-375

    View details for Web of Science ID A1987H114500011

    View details for PubMedID 18291859

  • INFLUENCE OF RECIPIENT ATRIAL CONTRACTION ON LEFT-VENTRICULAR FILLING DYNAMICS OF THE TRANSPLANTED HEART ASSESSED BY DOPPLER ECHOCARDIOGRAPHY AMERICAN JOURNAL OF CARDIOLOGY Valantine, H. A., Appleton, C. P., Hatle, L. K., Hunt, S. A., Stinson, E. B., Popp, R. L. 1987; 59 (12): 1159-1163

    Abstract

    Recipient atrial remnants retain electrical and mechanical activity after orthotopic cardiac transplantation. This study investigated the influence of recipient atrial contraction timing on Doppler ultrasound mitral flow velocity curves, isovolumic relaxation time, peak early mitral flow velocity (M1), mitral valve pressure half-time and peak mitral flow velocity due to atrial systole (M2). Clearly identifiable recipient atrial electrical activity (P waves) was present in 7 of 10 patients studied early postoperatively 2 to 6 months (mean 2.5) (early group) and in 20 of 24 patients seen 1 to 11 years (mean 3) after transplantation (late group). Median age and gender distribution were similar in both groups. For analysis of its influence on isovolumic relaxation time, pressure half-time and M1, recipient atrial contraction was classified by its position in the cardiac cycle as early systole, late systole or diastole. For analysis of M2, it was classified as early diastole, late diastole or systole. Compared with its occurrence in diastole, recipient atrial contraction in late systole was associated with a shorter isovolumic relaxation time, shorter pressure half-time and higher M1. In early systole it was associated with a longer pressure half-time and lower M1 than in diastole; isovolumic relaxation time was unchanged. Recipient atrial contraction in early diastole resulted in a lower M2 than in systole, whereas simultaneous contraction of recipient and donor atria in late diastole resulted in an increase in M2. These results indicate that the timing of recipient atrial contraction and relaxation significantly influences left ventricular filling dynamics.

    View details for Web of Science ID A1987H365700028

    View details for PubMedID 3554953

  • DOPPLER ECHOCARDIOGRAPHIC INDEXES OF DIASTOLIC FUNCTION AS MARKERS OF ACUTE CARDIAC REJECTION TRANSPLANTATION PROCEEDINGS Valantine, H., Fowler, M., Hatle, L., Hunt, S., Billingham, M., STINSON, E., Popp, R. 1987; 19 (1): 2556-2559

    View details for Web of Science ID A1987G101500265

    View details for PubMedID 3547937

  • ECHOCARDIOGRAPHIC EVALUATION OF SPACE-SHUTTLE CREWMEMBERS JOURNAL OF APPLIED PHYSIOLOGY Bungo, M. W., GOLDWATER, D. J., Popp, R. L., Sandler, H. 1987; 62 (1): 278-283

    Abstract

    Echocardiographic measurements were obtained before and after space flight from 17 members of four shuttle crews. Measurements obtained 1 h after landing (L+0) compared with preflight values (n = 7) demonstrated an increase in heart rate (HR) (16 beats/min, 30.5%, P less than 0.05), mean arterial pressure (12%, P less than 0.05), and systemic vascular resistance (34%, P less than 0.05). End-diastolic volume index (EDVI) fell 17 ml/m2 (-23%, P less than 0.005) and stroke volume index (SVI) fell 15 ml/m2 (-28%, P less than 0.05). Repeat measurements taken 1-2 wk later (n = 17) demonstrated that HR had returned to normal (4 beats/min, P less than 0.05); however, EDVI remained significantly below preflight levels (-11%, P less than 0.005). End-systolic volume index (ESVI) was also still significantly lower (-23%, P less than 0.01). This delayed recovery occurred despite ability of the subjects to fully ambulate and exercise during the postflight period. These results indicate that spaceflight induces significant changes in heart volume affecting left ventricular function. The exact reasons for these specific changes remain unknown and will require additional measurements before, during, and after flight. The prolonged recovery period for the present subject group probably relates to their high level of aerobic conditioning.

    View details for Web of Science ID A1987G454400039

    View details for PubMedID 3558187

  • PATTERNS AND TIMING OF DOPPLER-DETECTED INTRACAVITARY AND AORTIC FLOW IN HYPERTROPHIC CARDIOMYOPATHY JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Yock, P. G., Hatle, L., Popp, R. L. 1986; 8 (5): 1047-1058

    Abstract

    This study describes the velocity characteristics of left ventricular and aortic outflow in 25 patients with hypertrophic "obstructive" cardiomyopathy. Systematic pulsed and continuous wave Doppler analysis combined with phonocardiography and M-mode echocardiography was used to establish the pattern and timing of outflow in the basal and provoked states. This analysis suggests that 1) the high velocity left ventricular outflow jet can be reliably discriminated from both aortic flow and the jet of mitral regurgitation using Doppler ultrasound; 2) the Doppler velocity contour responds in a characteristic fashion to provocative influences including extrasystole and Valsalva maneuver; 3) the onset of mitral regurgitation occurs well before detectable systolic anterior motion of the mitral valve; 4) left ventricular flow velocities are elevated at the onset of systolic anterior motion of the mitral valve, suggesting a significant contribution of the Venturi effect in displacing the leaflets and chordae; 5) the high velocities of the outflow jets are largely dissipated by the time flow reaches the aortic valve; and 6) late systolic flow in the ascending aorta is nonuniform, with formation of distinct eddies that may contribute to "preclosure" of the aortic valve.

    View details for Web of Science ID A1986E614200008

    View details for PubMedID 2876020

  • ULTRASONIC CHARACTERIZATION OF CANINE MYOCARDIUM CONTRACTION IEEE TRANSACTIONS ON ULTRASONICS FERROELECTRICS AND FREQUENCY CONTROL Wear, K. A., SHOUP, T. A., Popp, R. L. 1986; 33 (4): 347-353

    View details for Web of Science ID A1986C424400001

    View details for PubMedID 18291795

  • BETA-BLOCKADE IN THE COMPENSATION FOR BED-REST CARDIOVASCULAR DECONDITIONING - PHYSIOLOGIC AND PHARMACOLOGIC OBSERVATIONS AMERICAN JOURNAL OF CARDIOLOGY Sandler, H., GOLDWATER, D. J., Popp, R. L., SPACCAVENTO, L., HARRISON, D. C. 1985; 55 (10): D114-D119
  • NONINVASIVE INTRACARDIAC PRESSURE MEASUREMENT USING DOPPLER ULTRASOUND JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Popp, R. L., Yock, P. G. 1985; 6 (4): 757-758

    View details for Web of Science ID A1985ASE5100007

    View details for PubMedID 3897341

  • A PHYSICIANS VIEW OF ECHOCARDIOGRAPHIC IMAGING HEWLETT-PACKARD JOURNAL Popp, R. L. 1983; 34 (10): 13-16
  • NON-INVASIVE DIAGNOSIS OF LEFT ATRIAL-MYXOMA WESTERN JOURNAL OF MEDICINE ECHT, D. S., GUTHANER, D. F., Blank, N., Popp, R. L. 1983; 138 (5): 722-725

    View details for Web of Science ID A1983QR18200026

    View details for PubMedID 6603714

  • ECHOCARDIOGRAPHY IN ACQUIRED HEART-DISEASE CIRCULATION Popp, R. L., Takamoto, T. 1983; 67 (4): 935-938

    View details for Web of Science ID A1983QG71000033

    View details for PubMedID 6337743

  • LIMITATIONS OF COMPARING LEFT-VENTRICULAR VOLUMES BY 2 DIMENSIONAL ECHOCARDIOGRAPHY, MYOCARDIAL MARKERS AND CINEANGIOGRAPHY AMERICAN JOURNAL OF CARDIOLOGY Schnittger, I., Fitzgerald, P. J., Daughters, G. T., Ingels, N. B., KANTROWITZ, N. E., Schwarzkopf, A., MEAD, C. W., Popp, R. L. 1982; 50 (3): 512-519

    View details for Web of Science ID A1982PE99400013

    View details for PubMedID 7113934

  • ADVANCING THE DIAGNOSIS OF LEFT ATRIAL-MYXOMA CHEST ECHT, D. S., Green, S. E., Popp, R. L. 1982; 82 (5): 522-524
  • INVITRO EVALUATION OF AN ULTRASONIC 3-DIMENSIONAL IMAGING AND VOLUME SYSTEM ULTRASONIC IMAGING Brinkley, J. F., MURAMATSU, S. K., MCCALLUM, W. D., Popp, R. L. 1982; 4 (2): 126-139

    View details for Web of Science ID A1982NQ95600003

    View details for PubMedID 7201694

  • M-MODE ECHOCARDIOGRAPHIC ASSESSMENT OF LEFT-VENTRICULAR FUNCTION AMERICAN JOURNAL OF CARDIOLOGY Popp, R. L. 1982; 49 (5): 1312-1318

    View details for Web of Science ID A1982NH12800032

    View details for PubMedID 7064856

  • THE CONCEPT OF 3 DIMENSIONAL RESOLUTION IN ECHOCARDIOGRAPHIC IMAGING ULTRASOUND IN MEDICINE AND BIOLOGY Joynt, L., Popp, R. L. 1982; 8 (3): 237-247

    View details for Web of Science ID A1982NP24300001

    View details for PubMedID 7101572

  • INTRODUCTION - ECHOCARDIOGRAPHIC EVALUATION OF VENTRICULAR-FUNCTION - AN OVERVIEW AMERICAN JOURNAL OF CARDIOLOGY Feigenbaum, H., Henry, W. L., Pearlman, A. S., Popp, R. L. 1982; 49 (5): 1311-1312

    View details for Web of Science ID A1982NH12800031

    View details for PubMedID 7064855

  • SCREENING FOR ATRIAL SEPTAL-DEFECTS WITH ECHOCARDIOGRAPHY JOURNAL OF CARDIOVASCULAR MEDICINE French, J. W., Popp, R. L. 1981; 6 (5): 490-?
  • ROLE OF ECHOCARDIOGRAPHY IN DIAGNOSIS AND MANAGEMENT OF VALVULAR HEART-DISEASE MODERN CONCEPTS OF CARDIOVASCULAR DISEASE Green, S. E., Popp, R. L. 1981; 50 (6): 31-36
  • APPARENT ASYMMETRIC SEPTAL HYPERTROPHY DUE TO ANGLED INTER-VENTRICULAR SEPTUM AMERICAN JOURNAL OF CARDIOLOGY Fowles, R. E., Martin, R. P., Popp, R. L. 1980; 46 (3): 386-392

    View details for Web of Science ID A1980KG48100005

    View details for PubMedID 7191198

  • CLINICAL UTILITY OF 2 DIMENSIONAL ECHOCARDIOGRAPHY IN INFECTIVE ENDOCARDITIS AMERICAN JOURNAL OF CARDIOLOGY Martin, R. P., Meltzer, R. S., Chia, B. L., Stinson, E. B., Rakowski, H., Popp, R. L. 1980; 46 (3): 379-385

    View details for Web of Science ID A1980KG48100004

    View details for PubMedID 7415982

  • CLINICAL UTILITY OF 2-DIMENSIONAL ECHOCARDIOGRAPHY ACTA MEDICA SCANDINAVICA Rakowski, H., Martin, R. P., French, J. W., Popp, R. L. 1979: 68-78

    View details for Web of Science ID A1979GY67500006

    View details for PubMedID 286521

  • IDIOPATHIC HYPERTROPHIC SUB-AORTIC STENOSIS VIEWED BY WIDE-ANGLE, PHASED-ARRAY ECHOCARDIOGRAPHY CIRCULATION Martin, R. P., Rakowski, H., French, J., Popp, R. L. 1979; 59 (6): 1206-1217

    View details for Web of Science ID A1979GX15600016

    View details for PubMedID 571310

  • LEFT-VENTRICULAR FUNCTION - ASSESSMENT BY WIDE ANGLE 2-DIMENSIONAL ULTRASONIC SECTOR SCANNING ACTA MEDICA SCANDINAVICA Rakowski, H., Martin, R. P., Popp, R. L. 1979: 105-111

    View details for Web of Science ID A1979GY67500010

    View details for PubMedID 286501

  • VENTRICULAR SEPTAL-DEFECT NOTED BY 2-DIMENSIONAL ECHOCARDIOGRAPHY CHEST Meltzer, R. S., SCHWARTZ, J., French, J., Popp, R. L. 1979; 76 (4): 455-457

    View details for Web of Science ID A1979HP30400020

    View details for PubMedID 477436

  • RELIABILITY AND REPRODUCIBILITY OF 2 DIMENSIONAL ECHOCARDIOGRAPHIC MEASUREMENT OF THE STENOTIC MITRAL-VALVE ORIFICE AREA AMERICAN JOURNAL OF CARDIOLOGY Martin, R. P., Rakowski, H., Kleiman, J. H., Beaver, W., London, E., Popp, R. L. 1979; 43 (3): 560-568

    View details for Web of Science ID A1979GL34000014

    View details for PubMedID 420105

  • 2-DIMENSIONAL ECHOCARDIOGRAPHIC QUANTIFICATION OF INFARCT SIZE ALTERATION BY PHARMACOLOGIC AGENTS AMERICAN JOURNAL OF CARDIOLOGY Meltzer, R. S., WOYTHALER, J. N., Buda, A. J., Griffin, J. C., Harrison, W. D., Martin, R. P., HARRISON, D. C., Popp, R. L. 1979; 44 (2): 257-262
  • ECHOCARDIOGRAPHY IN DISCRETE SUB-AORTIC STENOSIS CIRCULATION Krueger, S. K., French, J. W., Forker, A. D., Caudill, C. C., Popp, R. L. 1979; 59 (3): 506-513

    View details for Web of Science ID A1979GK12000012

    View details for PubMedID 761330

  • CURRENT CONCEPTS IN CARDIOLOGY - ECHOCARDIOGRAPHIC EVALUATION OF LEFT-VENTRICULAR FUNCTION NEW ENGLAND JOURNAL OF MEDICINE Popp, R. L. 1977; 296 (15): 856-858
  • MITRAL-VALVE PROLAPSE AND INFECTIVE ENDOCARDITIS AMERICAN JOURNAL OF MEDICINE CORRIGALL, D., Bolen, J., Hancock, E. W., Popp, R. L. 1977; 63 (2): 215-222

    View details for Web of Science ID A1977DR94700007

    View details for PubMedID 888845

  • MITRAL-VALVE PROLAPSE SYNDROME JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Popp, R. L., WINKLE, R. A. 1976; 236 (7): 867-870

    View details for Web of Science ID A1976CA63400032

    View details for PubMedID 947271

  • PHONOCARDIOGRAPHIC AND ECHOCARDIOGRAPHIC FEATURES OF RUPTURED AORTIC VALVULAR CUSP CHEST CORRIGALL, D., STRUNK, B. L., Popp, R. L. 1976; 69 (5): 669-671

    View details for Web of Science ID A1976BQ69700020

    View details for PubMedID 1269278

  • ECHOCARDIOGRAPHIC ASSESSMENT OF CARDIAC DISEASE CIRCULATION Popp, R. L. 1976; 54 (4): 538-552

    View details for Web of Science ID A1976CE72200003

    View details for PubMedID 786497

  • ECHOCARDIOGRAPHIC FEATURES OF SUPRAVALVULAR AORTIC-STENOSIS CIRCULATION BOLEN, J. L., Popp, R. L., French, J. W. 1975; 52 (5): 817-822

    Abstract

    A method for the echocardiographic detection of supravalvular aortic stenosis (SVAS) is described and the findings in a series of patients are presented. When compared to angiography, the echo tended to underestimate the severity of the supravalvular aortic obstruction. However, echocardiography appears to be a valuable, noninvasive method for detecting SVAS.

    View details for Web of Science ID A1975AT26800010

    View details for PubMedID 1175262

  • NONINVASIVE LEFT VENTRICULOGRAM NEW ENGLAND JOURNAL OF MEDICINE Popp, R. L. 1974; 291 (23): 1254-1255
  • ECHOCARDIOGRAPHIC CRITERIA IN DIAGNOSIS OF IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS CIRCULATION ROSSEN, R. M., GOODMAN, D. J., Ingham, R. E., Popp, R. L. 1974; 50 (4): 747-751

    View details for Web of Science ID A1974U467100016

    View details for PubMedID 4278516

  • ECHOCARDIOGRAPHIC FINDINGS IN DISCRETE SUBVALVULAR AORTIC-STENOSIS CIRCULATION Popp, R. L., SILVERMA, J. F., French, J. W., Stinson, E. B., HARRISON, D. C. 1974; 49 (2): 226-231

    View details for Web of Science ID A1974S094200004

    View details for PubMedID 4855729

  • IMPROVED METHOD FOR ECHOGRAPHIC DETECTION OF LEFT ATRIAL ENLARGEMENT CIRCULATION Brown, O. R., HARRISON, D. C., Popp, R. L. 1974; 50 (1): 58-64

    View details for Web of Science ID A1974T610500010

    View details for PubMedID 4276017

  • CORONARY-ARTERY DISEASE WITH IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS LANCET MARCUS, G. B., Popp, R. L., Stinson, E. B. 1974; 1 (7863): 901-903

    View details for Web of Science ID A1974S944000006

    View details for PubMedID 4133421

  • ILLUSTRATIVE ECHOCARDIOGRAM - ECHOCARDIOGRAPHIC PSEUDO IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS CHEST GOODMAN, D. J., ROSSEN, R. M., Popp, R. L. 1974; 66 (5): 573-574
  • ECHOCARDIOGRAPHIC ABNORMALITIES IN MITRAL-VALVE PROLAPSE SYNDROME CIRCULATION Popp, R. L., Brown, O. R., SILVERMA, J. F., HARRISON, D. C. 1974; 49 (3): 428-433

    View details for Web of Science ID A1974S351000010

    View details for PubMedID 4813176

  • [Use of ultrasonics in the diagnosis of heart diseases]. Terapevticheskii arkhiv Garrison, D. S., Popp, R. L., LOPETS, M. G. 1974; 46 (6): 128-135

    View details for PubMedID 4610874

  • VENTRICULAR SYSTOLIC SEPTAL THICKENING AND EXCURSION IN IDIOPATHIC HYPERTROPHIC SUBAORTIC STENOSIS NEW ENGLAND JOURNAL OF MEDICINE ROSSEN, R. M., GOODMAN, D. J., Ingham, R. E., Popp, R. L. 1974; 291 (25): 1317-1319

    View details for Web of Science ID A1974V010300001

    View details for PubMedID 4473712

  • SOUND IN CARDIAC DIAGNOSIS TERAPEVTICHESKII ARKHIV Garrison, D. S., Popp, R. L., LOPETS, M. G. 1974; 46 (6): 128-135
  • COMPUTER-PROCESSING OF ULTRASONIC DATA FROM CARDIOVASCULAR-SYSTEM COMPUTERS AND BIOMEDICAL RESEARCH Hirsch, M., Sanders, W. J., Popp, R. L., HARRISON, D. C. 1973; 6 (4): 336-346

    View details for Web of Science ID A1973Q621800004

    View details for PubMedID 4582625

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