175 results on '"R. Kuntz"'
Search Results
102. Spectral shifts of the p-aminophenylthyl radical absorption and emission in solution
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G.H. Morine and Robert R. Kuntz
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Dipole ,Chemistry ,Excited state ,Analytical chemistry ,General Physics and Astronomy ,Ionic bonding ,Resonance ,Physics::Chemical Physics ,Physical and Theoretical Chemistry ,Absorption (electromagnetic radiation) ,Fluorescence spectra - Abstract
The absorption and fluorescence spectra of the reactive p-aminophenylthiyl radical were observed in several solvents. Analysis of the spectral shifts yielded dipole moments for the ground and excited states of 4.3 D and 7.3 D, respectively. These values suggest a significant contribution of ionic resonance forms to both states.
- Published
- 1979
103. Flash photolysis of N-acetyl-L-tryptophanamide; acid-base equilibrium of the radical transients
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Robert R. Kuntz, Wynn A. Volkert, Camillo A. Ghiron, and R. F. Evans
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Deprotonation ,Chemistry ,General Physics and Astronomy ,Flash photolysis ,Acid–base reaction ,Physical and Theoretical Chemistry ,Photochemistry ,N-acetyl-L-tryptophanamide - Abstract
The transient with a λ max at 570 m observed in the flash photolysis of N-acetyl-L-tryptophanamide is confirmed to be the positive radical. This species is in rapid equilibrium with its deprotonated form (λ max =510 mm) with a pK of 4.3.
- Published
- 1976
104. Reactions of hydrogen atoms with simple thiols
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Robert R. Kuntz
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Hydrogen ,Chemistry ,Simple (abstract algebra) ,General Engineering ,chemistry.chemical_element ,Physical and Theoretical Chemistry ,Photochemistry - Published
- 1967
105. The Solubility of Mercury in Hydrocarbons
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Gilbert J. Mains and Robert R. Kuntz
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Chemistry ,Environmental chemistry ,General Engineering ,chemistry.chemical_element ,Physical and Theoretical Chemistry ,Solubility ,Mercury (element) - Published
- 1964
106. The Hg(3P1)-Sensitized Decomposition of n-Hexane Vapor
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Robert R. Kuntz
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Hexane ,chemistry.chemical_compound ,chemistry ,General Engineering ,Physical and Theoretical Chemistry ,Decomposition ,Nuclear chemistry - Published
- 1965
107. Effects of the Large June 1975 Meteoroid Storm on Earth's Ionosphere
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V. L. R. Kuntz, Pierre Kaufmann, L. R. Piazza, J. W. S. Vilas Boas, N. M. Paes Leme, K. Brecher, and J. Crouchley
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Daytime ,Multidisciplinary ,Meteoroid ,Environmental science ,Storm ,Sunset ,Very low frequency ,Ionosphere ,Atmospheric sciences ,Southern Hemisphere ,Radio wave - Abstract
The June 1975 meteoroid storm detected on the moon by the Apollo seismometers was the largest ever observed. Reexamination of radio data taken at that time showed that the storm also produced pronounced disturbances on Earth, which were recorded as unique phase anomalies on very low frequency (VLF) radio propagation paths in the low terrestrial ionosphere. Persistent effects were observed for the major storm period (20 to 30 June 1975), including reductions in the diurnal phase variation, advances in the nighttime and daytime phase levels, and reductions in the sunset phase delay rate. Large nighttime phase advances, lasting a few hours, were detected on some days at all VLF transmissions, and for the shorter propagation path they were comparable to solar Lyman alpha daytime ionization. Ion production rates attributable to the meteor storm were estimated to be about 0.6 to 3.0 ions per centimeter cubed per second at the E and D regions, respectively. The storm was a sporadic one with a radiant (that is, the point of apparent origin in the sky) located in the Southern Hemisphere, with a right ascension 1 to 2 hours larger than the sun's right ascension.
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- 1989
108. [The angiographic diagnosis of islet cell tumours. Results in 34 patients (author's transl)]
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K R, Schmidt, K J, Pfeifer, F, Spelsberg, R, Wirsching, and R, Kuntz
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Pancreatic Neoplasms ,Hyperinsulinism ,Angiography ,Humans ,Adenoma, Islet Cell - Abstract
Between 1965 and 1979, 34 patients with organic hyperinsulinism were examined angiographically. By observing the following points it should be possible to diagnose tumours greater than 1 cm, whatever their position in the pancreas: 1) Use of high performance generators and tubes which permit one to employ fine focus, low kv and high mAs. 2) Optimum imaging systems (carbon fibre table top, high intensity screens). 3) Selective catheterisation, large quantities of contrast per unit time and adequate duration of the filming sequence. 4) Pharmacoangiography and subtractions may be valuable in some cases.
- Published
- 1980
109. Flash photolysis of human serum albumin: characterization of the indole triplet absorption spectrum and decay at ambient temperature
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Wynn A. Volkert, Robert R. Kuntz, B. Hicks, M. White, and Camillo A. Ghiron
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Indole test ,Quantitative Biology::Biomolecules ,Multidisciplinary ,Indoles ,Photolysis ,Absorption spectroscopy ,biology ,Chemistry ,Spectrum Analysis ,Tryptophan ,Human serum albumin ,Photochemistry ,Kinetics ,medicine ,biology.protein ,Flash photolysis ,Humans ,Singlet state ,Bovine serum albumin ,Phosphorescence ,Serum Albumin ,medicine.drug ,Research Article - Abstract
The method of flash photolysis was used to identify the transient absorption spectrum and to characterize the decay kinetics of the indole triplet of human serum albumin. This protein was studied because it contains a single indole side chain which is deeply buried in an expandable oily region and because the phosphorescence of the homologous indole in bovine serum albumin could not be detected at ambient temperatures. The transient was identified on the following basis: (i) its triplet-triplet absorption spectrum was similar to those previously reported for indole and tryptophan; (ii) it was quenched by small quantities of oxygen; and (iii) it was photobleached by 370- to 700-nm light. In a nitrogen-saturated solution at room temperature, the indole triplet decays exponentially for more than a factor of 10 with a lifetime of 0.5 msec. These observations suggest that, because of its exponential decay and relatively long lifetime, the triplet will be more valuable than the indole singlet as an intrinsic reporter group for the study of the structure and dynamics of proteins in solution.
- Published
- 1978
110. [Unusual complications during surgical intestinal support using the Miller-Abbott probe]
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F, Spelsberg, G, Salzmann, and R, Kuntz
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Abdomen, Acute ,Adult ,Male ,Humans ,Surgical Instruments - Published
- 1975
111. [Programming and structure of a relation-oriented data bank system for registration, blood alcohol values and documentation of findings at the forensic medicine institute of the Heidelberg University]
- Author
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R, Kuntz and R, Aderjan
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Ethanol ,Microcomputers ,Accidents, Traffic ,Germany, West ,Humans ,Documentation ,Registries ,Alcoholic Intoxication ,Software ,Information Systems - Abstract
We report on a data base system for general registration including blood alcohol results which is in operation at the Institute of Forensic Medicine at Heidelberg University since january 1987. It is run on personal computers using dBase III plus as data base software. Working with the system has been adapted to the mode of operation hitherto. It's main purpose is to offer a general mean to standardize the documentation of results in the different fields of forensic medicine. At present it is run parallel with the registration by means of hand-written books. It's main advantage is the rapid search for all occurring names and files. Blood alcohol results are typed at the screen and printed out on the institute's standard form, with the expert's opinion being composed of text blocks. The essential data are extracted and transferred to the data base. A network of personal computers at different locations in the institute will be installed in the near future. A print-out of the data base will replace the hand-written registration, and the registration files will be completed by result files.
- Published
- 1989
112. [The diagnosis and therapy of mediastinal tumors (author's transl)]
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G, Salzmann, R, Kuntz, and F, Spelsberg
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Adult ,Male ,Adolescent ,Thymoma ,Endoscopy ,Middle Aged ,Hodgkin Disease ,Mediastinal Neoplasms ,Diagnosis, Differential ,Postoperative Complications ,Mediastinal Cyst ,Child, Preschool ,Mediastinal Diseases ,Humans ,Female ,Child ,Aged ,Follow-Up Studies - Abstract
From 1965 to 1973, 82 patients were operated on for mediastinal tumor. 42.7% of them were incidental radiological findings. Preoperatively, 66% of the mediastinal tumors were not morphologically confirmed. The lethality of the operation was 1.22%. Thymomas (29.3%) were the most frequent findings. 34.2% were malignant. While most patients with benign mediastinal tumors are cured by the operation, the 5 year survival rate for those with malignant tumors was 22%. Further special investigative procedures should only follow a guiding survey radiography in two planes if they can be expected to provide essential information on operability, operational tactics and approach.
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- 1976
113. Der primäre Hyperparathyreoidismus mit renaler Manifestation. Diagnostik, Therapie und Langzeitergebnisse
- Author
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F. Spelsberg and R. Kuntz
- Abstract
Im eigenen Krankengut zeigten sich seit 1960 durch die zunehmend verbesserte Diagnostik sprunghaft ansteigende Patientenzahlen mit einer Erstoperation bei histologisch gesichertem Hyperparathyreoidismus (1.1.1960 bis 30.9.1979; n = 251). Die 223 Patienten mit primarem Hyperparathyreoidismus machen dabei 88,9% aller wegen Nebenschilddrusendysfunktion operierten Patienten aus. Am haufigsten fand sich mit 66% eine renale Manifestation, die sich, bezogen auf das Gesamtkrankengut, auf 60,1% mit einer Nephrolithiasis, 13,9% mit einer Nephrokalzinose und auf 12,8% mit einer Niereninsuffizienz verteilte.
- Published
- 1980
114. Letter: The reactions of hydrogens atoms in aqueous solutions: effect of pH on reactions with cysteine and penicillamine
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J T, Wu and R R, Kuntz
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Solutions ,Radiation-Sensitizing Agents ,Penicillamine ,Water ,Radiation-Protective Agents ,Cysteine ,Hydrogen-Ion Concentration ,Hydrogen - Published
- 1975
115. The reactions of hydrogen atoms in aqueous solutions: thiols
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T L, Tung and R R, Kuntz
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Radiochemistry ,Cysteamine ,Penicillamine ,Radiation-Protective Agents ,Cysteine ,Sulfhydryl Compounds ,Propionates ,Hydrogen ,Mercaptoethanol - Published
- 1973
116. ChemInform Abstract: WASSERSTOFF-ABSPALTUNGSRK. DES CF3-CCL2-RADIKALS
- Author
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Fred B. Wampler and Robert R. Kuntz
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Chemistry ,General Medicine ,Medicinal chemistry - Published
- 1972
117. Hydrated electron reactions with thiols in acidic aqueous solutions
- Author
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T L, Tung and R R, Kuntz
- Subjects
Radiation Effects ,Solutions ,Cysteamine ,Penicillamine ,Water ,Cysteine ,Sulfhydryl Compounds ,Hydrogen-Ion Concentration - Published
- 1973
118. ChemInform Abstract: PYROLYSE VON HEXACHLORAETHAN
- Author
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Merle L. White and Robert R. Kuntz
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Chemistry ,Organic chemistry ,General Medicine - Published
- 1973
119. An estimate of direct NH bond cleavage in the photolysis of indole derivatives
- Author
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W. A. Volkert, Camillo A. Ghiron, and Robert R. Kuntz
- Subjects
Indole test ,Chemistry ,General Chemical Engineering ,Photodissociation ,General Physics and Astronomy ,General Chemistry ,Photochemistry ,Bond cleavage - Published
- 1977
120. The Reactions of Hydrogen Atoms in Aqueous Solutions: Effect of pH on Reactions with Cysteine and Penicillamine
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Jiunn-tsair Wu and Robert R. Kuntz
- Subjects
chemistry.chemical_classification ,Radiation ,Aqueous solution ,Hydrogen ,Chemistry ,Penicillamine ,Inorganic chemistry ,Biophysics ,chemistry.chemical_element ,Dissociation (chemistry) ,Amino acid ,Reaction rate constant ,medicine ,Radiology, Nuclear Medicine and imaging ,medicine.drug ,Cysteine - Abstract
The total rate constant for H-atom reactions with cysteine and penicillamine has been determined at pH 1 and pH 6 utilizing a photolytic source of H-atoms. The effect of COOH dissociation is to increase k/sub cysteine/ by 1.3 and k/sub penicillamine/ by 1.75. This effect is of the same magnitude as that observed for nonsulfhydryl amino acids. At higher pH values, dissociation of NH$sub 3$$sup +$ causes further enhancement of the rate for penicillamine. The mechanism of H-atom reactions with these amino acids appears to be independent of pH in the range of 1 to 6. (auth)
- Published
- 1975
121. The Reactions of Hydrogen Atoms in Aqueous Solutions: Thiols
- Author
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Robert R. Kuntz and Tzu-Lin Tung
- Subjects
Sh groups ,Radiation ,Aqueous solution ,Hydrogen ,Chemistry ,Inorganic chemistry ,Biophysics ,chemistry.chemical_element ,Hydrogen atom ,Radiation chemistry ,Medicinal chemistry ,Reaction rate constant ,Radiolysis ,Molecule ,Radiology, Nuclear Medicine and imaging - Abstract
k4 ks two mechanisms: (a) H + RSH- Hs + RS, and b) H + RSH H2S + R. The rate constant for reaction 4 is influenced by the presence of functional groups within the molecule. It is also found that reaction 4 is the predominant mechanism for hydrogen atom reaction with primary sulfhydryl compounds while reaction 5 is most important for secondary and tertiary SH groups. The relationship of these results to observed
- Published
- 1973
122. Hydrated Electron Reactions with Thiols in Acidic Aqueous Solutions
- Author
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Tzu-Lin Tung and Robert R. Kuntz
- Subjects
Radiation ,Aqueous solution ,Inorganic chemistry ,Biophysics ,Protonation ,Solvated electron ,Chemical reaction ,Dissociation (chemistry) ,chemistry.chemical_compound ,Reaction rate constant ,chemistry ,Ionic strength ,Zwitterion ,Radiology, Nuclear Medicine and imaging - Abstract
The rates of hydrated electron reactions with cysteamine, cysteine, thioglycol, α-mercaptopropionic acid, β-mercaptopropionic acid, and penicillamine have been studied in the pH 1-3 region. Hydrogen yields, which are a function of pH in this region, were used to monitor the competition between H+ and RSH for hydrated electrons. Corrections were applied to the observed rate constants to account for dissociation of the COOH group and the ionic strength effect on hydrated electron reactions. In the cases of cysteine and penicillamine, the rate constants for reaction with protonated amino acids at infinite dilution were greater by a factor of 3-5 than those for reaction with the zwitterion. Uncharged species show no pH dependence of the rate constant within this region. All rate constants measured were of comparable magnitude and approached the diffusion controlled limit.
- Published
- 1973
123. Photocatalytic reduction of acetylene by [MoOCl(dppe) 2] +Cl − on TiO 2
- Author
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R. Kuntz, Robert
- Published
- 1994
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124. Health Product Manufacturers and Innovators COVID-19 Impact Assessment: Lessons Learned and Compelling Needs.
- Author
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Mammen M, Narasimhan V, Kuntz R, Lewis-Hall F, Poul M, and Schechter A
- Abstract
Competing Interests: Conflict-of-Interest Disclosures: Dr. Lewis-Hall discloses that she is a member of the board of directors for SpringWorks Therapeutics, Exact Sciences, and 1Life Healthcare; she is a consultant for PhRMA; and she is an advisor to SAAMA Technologies, Topography Health, and Catalio. Dr. Mammen discloses that his employer received funding from the US government to develop a COVID-19 vaccine; that his employer collaborated with BCG; that his employer’s COVID-19 vaccine has received emergency use authorization in the US, European Union, and other countries; and that Johnson & Johnson is a multi-faceted company that has pharmaceutical, consumer, and medical devices businesses. Dr. Narasimhan discloses that his employer is currently undertaking an internal drug discovery program toward a pan-Coronavirus Mpro inhibitor; that his employer has an option and license agreement to develop, manufacture and commercialize two Molecular Partners’ anti-COVID-19 DARPin® candidates; and that his employer has initial agreements with Pfizer-BioNTech and CureVac to manufacture their COVID-19 vaccines, and with Roche for the production of the API for Actemra/RoActemra®. Mr. Schechter discloses that his employer has performed COVID-19 diagnostic and antibody testing, supported COVID-19 clinical trials and study opportunities of potential treatments and vaccines with external sponsors, and worked with the U.S. Centers for Disease Control and Prevention to provide sequencing of samples of SARS-CoV-2 and that for these laboratory testing and drug development services, his employer has received reimbursement from various sources, including governmental agencies; and that in preparing the submitted work, Labcorp consulted with the American Clinical Laboratory Association, the national trade association representing leading clinical laboratories.
- Published
- 2022
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125. Attribution of Adverse Events Following Coronary Stent Placement Identified Using Administrative Claims Data.
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Dhruva SS, Parzynski CS, Gamble GM, Curtis JP, Desai NR, Yeh RW, Masoudi FA, Kuntz R, Shaw RE, Marinac-Dabic D, Sedrakyan A, Normand ST, Krumholz HM, and Ross JS
- Subjects
- Aged, Aged, 80 and over, Coronary Restenosis mortality, Coronary Restenosis therapy, Coronary Thrombosis mortality, Coronary Thrombosis therapy, Databases, Factual, Female, Humans, Male, Myocardial Infarction mortality, Myocardial Infarction therapy, Percutaneous Coronary Intervention mortality, Product Surveillance, Postmarketing, Registries, Retreatment, Risk Assessment, Risk Factors, Time Factors, Treatment Outcome, United States epidemiology, Administrative Claims, Healthcare, Drug-Eluting Stents, Medicare, Percutaneous Coronary Intervention adverse effects, Percutaneous Coronary Intervention instrumentation
- Abstract
Background More than 600 000 coronary stents are implanted during percutaneous coronary interventions (PCIs) annually in the United States. Because no real-world surveillance system exists to monitor their long-term safety, claims data are often used for this purpose. The extent to which adverse events identified with claims data can be reasonably attributed to a specific medical device is uncertain. Methods and Results We used deterministic matching to link the NCDR (National Cardiovascular Data Registry) CathPCI Registry to Medicare fee-for-service claims for patients aged ≥65 years who underwent PCI with drug-eluting stents (DESs) between July 1, 2009 and December 31, 2013. We identified subsequent PCIs within 1 year of the index procedure in Medicare claims as potential safety events. We linked these subsequent PCIs back to the NCDR CathPCI Registry to ascertain how often the revascularization could be reasonably attributed to the same coronary artery as the index PCI (ie, target vessel revascularization). Of 415 306 DES placements in 368 194 patients, 33 174 repeat PCIs were identified in Medicare claims within 1 year. Of these, 28 632 (86.3%) could be linked back to the NCDR CathPCI Registry; 16 942 (51.1% of repeat PCIs) were target vessel revascularizations. Of these, 8544 (50.4%) were within a previously placed DES: 7652 for in-stent restenosis and 1341 for stent thrombosis. Of 16 176 patients with a claim for acute myocardial infarction in the follow-up period, 4446 (27.5%) were attributed to the same coronary artery in which the DES was implanted during the index PCI (ie, target vessel myocardial infarction). Of 24 288 patients whose death was identified in claims data, 278 (1.1%) were attributed to the same coronary artery in which the DES was implanted during the index PCI. Conclusions Most repeat PCIs following DES stent implantation identified in longitudinal claims data could be linked to real-world registry data, but only half could be reasonably attributed to the same coronary artery as the index procedure. Attribution among those with acute myocardial infarction or who died was even less frequent. Safety signals identified using claims data alone will require more in-depth examination to accurately assess stent safety.
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- 2020
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126. Advancing the Science of Healthcare Service Delivery: The NHLBI Corporate Healthcare Leaders' Panel.
- Author
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Sampson UKA, McGlynn EA, Perlin JB, Frisse ME, Arnold SB, Benz EJ Jr, Brennan T, Briss P, Beeuwkes Buntin MJ, Khosla S, King RG, Kuntz R, Leider H, Ling SM, Macrae J, Murray R, Thrailkill E, Wager C, Witchey D, and Jacobson HR
- Subjects
- Biomedical Research, Humans, United States, Cardiology, Cardiovascular Diseases therapy, Consensus, Delivery of Health Care standards, Leadership
- Abstract
There is a growing gap between available science and evidence and the ability of service providers to deliver high-quality care in a cost-effective way to the entire population. We believe that the chasm between knowledge and action is due to a lack of concerted effort among all organizations that deliver health care services across the life span of patients. Broad participation is needed and necessitates a far more explicit and concerted public-private partnership focused on large-scale transformation. In this context, the National Heart, Lung, and Blood Institute convened a panel made up of leaders of corporate health care entities, including academic health centers, and government agency representatives to inform contemporary strategic partnerships with health care companies. This article provides insights from the meeting on how to execute a transformative innovation research agenda that will foster improvements in health care service delivery by leveraging the translation of biomedical research evidence in real-world settings., (Copyright © 2018 World Heart Federation (Geneva). All rights reserved.)
- Published
- 2018
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127. Overview and experience of the YODA Project with clinical trial data sharing after 5 years.
- Author
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Ross JS, Waldstreicher J, Bamford S, Berlin JA, Childers K, Desai NR, Gamble G, Gross CP, Kuntz R, Lehman R, Lins P, Morris SA, Ritchie JD, and Krumholz HM
- Subjects
- Humans, Clinical Trials as Topic, Information Dissemination methods
- Abstract
The Yale University Open Data Access (YODA) Project has facilitated access to clinical trial data since 2013. The purpose of this article is to provide an overview of the Project, describe key decisions that were made when establishing data sharing policies, and suggest how our experience and the experiences of our first two data generator partners, Medtronic, Inc. and Johnson & Johnson, can be used to enhance other ongoing or future initiatives.
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- 2018
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128. Quantifying the utilization of medical devices necessary to detect postmarket safety differences: A case study of implantable cardioverter defibrillators.
- Author
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Bates J, Parzynski CS, Dhruva SS, Coppi A, Kuntz R, Li SX, Marinac-Dabic D, Masoudi FA, Shaw RE, Warner F, Krumholz HM, and Ross JS
- Subjects
- Cardiac Surgical Procedures instrumentation, Cardiac Surgical Procedures statistics & numerical data, Data Interpretation, Statistical, Death, Sudden, Cardiac, Defibrillators, Implantable adverse effects, Heart Failure surgery, Humans, Primary Prevention, Product Surveillance, Postmarketing methods, Prosthesis Implantation instrumentation, Prosthesis Implantation statistics & numerical data, Sample Size, United States, Databases, Factual statistics & numerical data, Defibrillators, Implantable statistics & numerical data, Product Surveillance, Postmarketing statistics & numerical data, Prosthesis Failure, Registries statistics & numerical data
- Abstract
Purpose: To estimate medical device utilization needed to detect safety differences among implantable cardioverter defibrillators (ICDs) generator models and compare these estimates to utilization in practice., Methods: We conducted repeated sample size estimates to calculate the medical device utilization needed, systematically varying device-specific safety event rate ratios and significance levels while maintaining 80% power, testing 3 average adverse event rates (3.9, 6.1, and 12.6 events per 100 person-years) estimated from the American College of Cardiology's 2006 to 2010 National Cardiovascular Data Registry of ICDs. We then compared with actual medical device utilization., Results: At significance level 0.05 and 80% power, 34% or fewer ICD models accrued sufficient utilization in practice to detect safety differences for rate ratios <1.15 and an average event rate of 12.6 events per 100 person-years. For average event rates of 3.9 and 12.6 events per 100 person-years, 30% and 50% of ICD models, respectively, accrued sufficient utilization for a rate ratio of 1.25, whereas 52% and 67% for a rate ratio of 1.50. Because actual ICD utilization was not uniformly distributed across ICD models, the proportion of individuals receiving any ICD that accrued sufficient utilization in practice was 0% to 21%, 32% to 70%, and 67% to 84% for rate ratios of 1.05, 1.15, and 1.25, respectively, for the range of 3 average adverse event rates., Conclusions: Small safety differences among ICD generator models are unlikely to be detected through routine surveillance given current ICD utilization in practice, but large safety differences can be detected for most patients at anticipated average adverse event rates., (Copyright © 2018 John Wiley & Sons, Ltd.)
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- 2018
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129. Can machine learning complement traditional medical device surveillance? A case study of dual-chamber implantable cardioverter-defibrillators.
- Author
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Ross JS, Bates J, Parzynski CS, Akar JG, Curtis JP, Desai NR, Freeman JV, Gamble GM, Kuntz R, Li SX, Marinac-Dabic D, Masoudi FA, Normand ST, Ranasinghe I, Shaw RE, and Krumholz HM
- Abstract
Background: Machine learning methods may complement traditional analytic methods for medical device surveillance., Methods and Results: Using data from the National Cardiovascular Data Registry for implantable cardioverter-defibrillators (ICDs) linked to Medicare administrative claims for longitudinal follow-up, we applied three statistical approaches to safety-signal detection for commonly used dual-chamber ICDs that used two propensity score (PS) models: one specified by subject-matter experts (PS-SME), and the other one by machine learning-based selection (PS-ML). The first approach used PS-SME and cumulative incidence (time-to-event), the second approach used PS-SME and cumulative risk (Data Extraction and Longitudinal Trend Analysis [DELTA]), and the third approach used PS-ML and cumulative risk (embedded feature selection). Safety-signal surveillance was conducted for eleven dual-chamber ICD models implanted at least 2,000 times over 3 years. Between 2006 and 2010, there were 71,948 Medicare fee-for-service beneficiaries who received dual-chamber ICDs. Cumulative device-specific unadjusted 3-year event rates varied for three surveyed safety signals: death from any cause, 12.8%-20.9%; nonfatal ICD-related adverse events, 19.3%-26.3%; and death from any cause or nonfatal ICD-related adverse event, 27.1%-37.6%. Agreement among safety signals detected/not detected between the time-to-event and DELTA approaches was 90.9% (360 of 396, k =0.068), between the time-to-event and embedded feature-selection approaches was 91.7% (363 of 396, k =-0.028), and between the DELTA and embedded feature selection approaches was 88.1% (349 of 396, k =-0.042)., Conclusion: Three statistical approaches, including one machine learning method, identified important safety signals, but without exact agreement. Ensemble methods may be needed to detect all safety signals for further evaluation during medical device surveillance., Competing Interests: Disclosure JSR receives support from the US FDA as part of the Centers for Excellence in Regulatory Science and Innovation program and from the Laura and John Arnold Foundation to support the Collaboration on Research Integrity and Transparency at Yale. JSR, NRD, HMK, and GMG receive research support through Yale University from Johnson and Johnson to develop methods of clinical trial data sharing. JSR and GMG receive research support from the Blue Cross Blue Shield Association to better understand medical technology evidence generation. JSR, JPC, NRD, SXL, SLTM, IR, HMK, and CSP work under contract to the Centers for Medicare and Medicaid Services to develop and maintain performance measures that are used for public reporting. JVF receives salary support from the American College of Cardiology NCDR, and modest consulting fees from Janssen Pharmaceuticals. RK is an employee of Medtronic Inc. DMD is an employee of the FDA. HMK chairs a cardiac scientific advisory board for United Health, is a participant/participant representative of the IBM Watson Health Life Sciences Board, is a member of the Advisory Board for Element Science and the Physician Advisory Board for Aetna, and is the founder of Hugo, a personal health-information platform. The authors report no other conflicts of interest in this work.
- Published
- 2017
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130. Dorsal root ganglia neurite outgrowth measured as a function of changes in microelectrode array resistance.
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Renna JM, Stukel JM, Kuntz Willits R, and Engeberg ED
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- Animals, Cell Culture Techniques methods, Cells, Cultured, Chick Embryo, Electric Impedance, Ganglia, Spinal embryology, Microelectrodes, Neuronal Outgrowth, Cell Culture Techniques instrumentation, Ganglia, Spinal cytology, Neurites physiology
- Abstract
Current research in prosthetic device design aims to mimic natural movements using a feedback system that connects to the patient's own nerves to control the device. The first step in using neurons to control motion is to make and maintain contact between neurons and the feedback sensors. Therefore, the goal of this project was to determine if changes in electrode resistance could be detected when a neuron extended a neurite to contact a sensor. Dorsal root ganglia (DRG) were harvested from chick embryos and cultured on a collagen-coated carbon nanotube microelectrode array for two days. The DRG were seeded along one side of the array so the processes extended across the array, contacting about half of the electrodes. Electrode resistance was measured both prior to culture and after the two day culture period. Phase contrast images of the microelectrode array were taken after two days to visually determine which electrodes were in contact with one or more DRG neurite or tissue. Electrodes in contact with DRG neurites had an average change in resistance of 0.15 MΩ compared with the electrodes without DRG neurites. Using this method, we determined that resistance values can be used as a criterion for identifying electrodes in contact with a DRG neurite. These data are the foundation for future development of an autonomous feedback resistance measurement system to continuously monitor DRG neurite outgrowth at specific spatial locations.
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- 2017
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131. IDEAL-D: a rational framework for evaluating and regulating the use of medical devices.
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Sedrakyan A, Campbell B, Merino JG, Kuntz R, Hirst A, and McCulloch P
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- Humans, Medical Device Legislation, United Kingdom, United States, Device Approval legislation & jurisprudence, Device Approval standards, Equipment Design methods, Equipment Design standards, Equipment Safety methods, Equipment Safety standards
- Published
- 2016
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132. Modular scaffolds assembled around living cells using poly(ethylene glycol) microspheres with macroporation via a non-cytotoxic porogen.
- Author
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Scott EA, Nichols MD, Kuntz-Willits R, and Elbert DL
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- Hot Temperature, Humans, Light, Lysophospholipids administration & dosage, Neovascularization, Physiologic, Polymers chemistry, Scattering, Radiation, Sphingosine administration & dosage, Sphingosine analogs & derivatives, Sulfates chemistry, Surface-Active Agents chemistry, Temperature, Time Factors, Biocompatible Materials chemistry, Hydrogels chemistry, Microspheres, Polyethylene Glycols chemistry
- Abstract
Modular, bioactive, macroporous scaffolds were formed by crosslinking poly(ethylene glycol) (PEG) microspheres around living cells. Hydrogel microspheres were produced from reactive PEG derivatives in aqueous sodium sulfate solutions without the use of surfactants or copolymers. Microspheres were formed following thermally induced phase separation if the gel point was reached prior to extensive coarsening of the PEG-rich domains. Three types of PEG microspheres with different functionalities were used to form scaffolds: one type provided mechanical support, the second type provided controlled delivery of the angiogenesis-promoting molecule, sphingosine 1-phosphate (S1P) and the third type served as a slowly dissolving non-cytotoxic porogen. Scaffolds were formed by centrifuging microspheres in the presence of HepG2 hepatoma cells, resulting in a homogenous distribution of cells. During overnight incubation at 37 degrees C, the microspheres reacted with serum proteins in cell culture medium to stabilize the scaffolds. Within 2 days in culture, macropores formed due to the dissolution of the porogenic PEG microspheres, without affecting cell viability. Gradients in porosity were produced by varying the buoyancy of the porogenic microspheres. Conjugated RGD cell adhesion peptides and the delivery of S1P promoted endothelial cell infiltration through macropores in the scaffolds. The scaffolds presented here differ from previous hydrogel scaffolds in that: (i) cells are not encapsulated in hydrogel; (ii) macropores form in the presence of cells; and (iii) scaffold properties are controlled by the modular assembly of different microspheres that perform distinct functions.
- Published
- 2010
- Full Text
- View/download PDF
133. A review of the recent evidence (2006-2008) for 532-nm photoselective laser vaporisation and holmium laser enucleation of the prostate.
- Author
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Naspro R, Bachmann A, Gilling P, Kuntz R, Madersbacher S, Montorsi F, Reich O, Stief C, and Vavassori I
- Subjects
- Case-Control Studies, Cohort Studies, Evidence-Based Medicine, Humans, Male, Minimally Invasive Surgical Procedures methods, Postoperative Complications mortality, Postoperative Complications physiopathology, Prognosis, Prostatic Hyperplasia pathology, Risk Assessment, Severity of Illness Index, Transurethral Resection of Prostate methods, Treatment Outcome, Laser Therapy methods, Lasers, Solid-State therapeutic use, Prostatectomy methods, Prostatic Hyperplasia surgery
- Abstract
Context: Holmium laser enucleation of the prostate (HoLEP) and 532-nm laser vaporisation of the prostate (with potassium titanyl phosphate [KTP] or lithium borate [LBO]) are promising alternatives to transurethral resection of the prostate (TURP) and open prostatectomy (OP)., Objective: To assess safety, efficacy, and durability by analysing the most recent evidence of both techniques, aiming to identify advantages, pitfalls, and unresolved issues., Evidence Acquisition: A Medline search of recently published data (2006-2008) regarding both techniques over the last 2 yr (January 2006 to September 2008) was performed using evidence obtained from randomised trials (level of evidence: 1b), well-designed controlled studies without randomisation (level of evidence: 2a), individual cohort studies (level of evidence: 2b), individual case control studies (level of evidence: 3), and case series (level of evidence: 4)., Evidence Synthesis: In the last 2 yr, several case-control and cohort studies have demonstrated reproducibility, safety, and efficacy of HoLEP and 80-W KTP laser vaporisation. Four randomised controlled trials (RCTs) were available for HoLEP, two compared with TURP and two compared with OP, with follow-up >24 mo. Results confirmed general efficacy and durability of HoLEP, as compared with both standard techniques. Only two RCTs were available comparing KTP laser vaporisation with TURP with short-term follow-up, and only one RCT was available comparing KTP laser vaporisation with OP. The results confirmed the overall low perioperative morbidity of KTP laser vaporisation, although efficacy was comparable to TURP in the short term, despite a higher reoperation rate., Conclusions: Although they are at different points of maturation, KTP or LBO laser vaporisation and HoLEP are promising alternatives to both TURP and OP. Sufficient data proves HoLEP's durability for most prostate sizes at long-term follow-up; KTP laser vaporisation needs further evaluation to define the reoperation rate. Increasing the number of quality prospective RCTs with adequate follow-up is mandatory to tailor each technique to the right patient.
- Published
- 2009
- Full Text
- View/download PDF
134. [Therapy of benign prostatic hyperplasia -- TURP versus greenlight laser vaporization].
- Author
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Bachmann A and Kuntz R
- Subjects
- Clinical Trials as Topic, Follow-Up Studies, Holmium, Humans, Male, Reoperation, Time Factors, Laser Therapy adverse effects, Laser Therapy methods, Prostatectomy methods, Prostatic Hyperplasia surgery, Transurethral Resection of Prostate adverse effects
- Published
- 2007
135. Mechanical properties of layered poly (ethylene glycol) gels.
- Author
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Skornia SL, Bledsoe JG, Kelso B, and Kuntz Willitz R
- Abstract
Poly(ethylene glycol) (PEG) hydrogels have become a popular material for biomedical applications because of their versatility in use and design. As these gels are readily crosslinked under UV, microfabrication techniques have been investigated to manufacture complex three dimensional structures to better mimic the in vivo environment. This work investigated whether a layering technique to fabricate gels offered sufficient strength between the layers to perform similarly in mechanical testing to unlayered gels. Two mechanical tests were performed: tensile tests and peel tests. The tensile tests, which examined sample gels whose test sections were crosslinked for different durations, demonstrated no statistical differences in elastic modulus between sample and control gels. As expected, a statistical increase in the elastic modulus was found with increased PEG concentration. Comparison of the yield stress between samples and controls illustrated differences with total crosslinking duration, which may be due to the decreased molecular weight of the chains with decreased crosslinking time. In peel tests, no statistical differences of maximum peel force were found between samples and controls. However, an increase in the maximum peel force was found with increasing concentration of PEG. Overall, this study demonstrates that the layering process described for the PEG gels has minimal impact on the tested mechanical properties of the system. As mechanical properties are critical to the design of tissue engineered devices, these results demonstrate that this fabrication method may be appropriate for further study as a scaffold for complex cellular systems.
- Published
- 2007
136. Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) I. Energy intake.
- Author
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Kuntz R, Kubalek C, Ruf T, Tataruch F, and Arnold W
- Subjects
- Animals, Diet, Dietary Fiber administration & dosage, Digestion, Female, Male, Nutritional Status, Animals, Wild physiology, Energy Intake, Energy Metabolism, Horses physiology, Seasons
- Abstract
Large ruminants respond to changing plant phenology during winter by decreasing voluntary food intake, increasing gut passage time and utilizing body fat reserves. It is uncertain, however, how other large mammals with a non-ruminant digestive physiology cope with winter forage conditions. Therefore, we investigated seasonality of energy intake in a large herbivorous wild mammal, the Przewalski horse (Equus ferus przewalskii). Throughout all seasons we used the n-alkane method to measure daily dry matter intake (DMI), diet composition and digestion, and determined an index of gut passage time in horses living under close to natural conditions. DMI correlated positively with its content of crude protein and nitrogen-free extract. Independent of these effects, DMI further varied seasonally with a peak in autumn and a nadir in late winter. Fluctuations of DMI corresponded to the annual change in body condition, which decreased during winter while energy reserves were depleted, and increased during the fattening period. Gut passage time varied in the course of the year and was longer during winter when the diet was high in crude fibre. Nevertheless, changes in gut passage time occurred rather independently of changes in forage composition and DMI, suggesting endogenous control for timely adaption of the digestive strategy to meet predictable changes in forage quality.
- Published
- 2006
- Full Text
- View/download PDF
137. Seasonal adjustment of energy budget in a large wild mammal, the Przewalski horse (Equus ferus przewalskii) II. Energy expenditure.
- Author
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Arnold W, Ruf T, and Kuntz R
- Subjects
- Animals, Body Temperature, Body Temperature Regulation, Eating, Female, Heart Rate, Male, Motor Activity, Pregnancy, Reproduction, Animals, Wild physiology, Energy Metabolism, Horses physiology, Seasons
- Abstract
Many large mammals show pronounced seasonal fluctuations of metabolic rate (MR). It has been argued, based on studies in ruminants, that this variation merely results from different levels of locomotor activity (LA), and heat increment of feeding (HI). However, a recent study in red deer (Cervus elaphus) identified a previously unknown mechanism in ungulates--nocturnal hypometabolism--that contributed significantly to reduced energy expenditure, mainly during late winter. The relative contribution of these different mechanisms to seasonal adjustments of MR is still unknown, however. Therefore, in the study presented here we quantified for the first time the independent contribution of thermoregulation, LA and HI to heart rate (f(H)) as a measure of MR in a free-roaming large ungulate, the Przewalski horse or Takhi (Equus ferus przewalskii Poljakow). f(H) varied periodically throughout the year with a twofold increase from a mean of 44 beats min(-1) during December and January to a spring peak of 89 beats min(-1) at the beginning of May. LA increased from 23% per day during December and January to a mean level of 53% per day during May, and declined again thereafter. Daily mean subcutaneous body temperature (T(s)) declined continuously during winter and reached a nadir at the beginning of April (annual range was 5.8 degrees C), well after the annual low of air temperature and LA. Lower T(s) during winter contributed considerably to the reduction in f(H). In addition to thermoregulation, f(H) was affected by reproduction, LA, HI and unexplained seasonal variation, presumably reflecting to some degree changes in organ mass. The observed phase relations of seasonal changes indicate that energy expenditure was not a consequence of energy uptake but is under endogenous control, preparing the organism well in advance of seasonal energetic demands.
- Published
- 2006
- Full Text
- View/download PDF
138. Complications of transurethral resection of the prostate (TURP)--incidence, management, and prevention.
- Author
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Rassweiler J, Teber D, Kuntz R, and Hofmann R
- Subjects
- Humans, Incidence, Male, Prostate pathology, Prostate surgery, Transurethral Resection of Prostate mortality, Postoperative Complications prevention & control, Transurethral Resection of Prostate adverse effects, Transurethral Resection of Prostate methods
- Abstract
Objectives: To update the complications of transurethral resection of the prostate (TURP), including management and prevention based on technological evolution., Methods: Based on a MEDLINE search from 1989 to 2005, the 2003 results of quality management of Baden-Württemberg, and long-term personal experience at three German centers, the incidence of complications after TURP was analyzed for three subsequent periods: early (1979-1994); intermediate (1994-1999); and recent (2000-2005) with recommendations for management and prevention., Results: Technological improvements such as microprocessor-controlled units, better armamentarium such as video TUR, and training helped to reduce perioperative complications (recent vs. early) such as transfusion rate (0.4% vs. 7.1%), TUR syndrome (0.0% vs. 1.1%), clot retention (2% vs. 5%), and urinary tract infection (1.7% vs. 8.2%). Urinary retention (3% vs. 9%) is generally attributed to primary detrusor failure rather than to incomplete resection. Early urge incontinence occurs in up to 30-40% of patients; however, late iatrogenic stress incontinence is rare (<0.5%). Despite an increasing age (55% of patients are older than 70), the associated morbidity of TURP maintained at a low level (<1%) with a mortality rate of 0-0.25%. The major late complications are urethral strictures (2.2-9.8%) and bladder neck contractures (0.3-9.2%). The retreatment rate range is 3-14.5% after five years., Conclusions: TURP still represents the gold standard for managing benign prostatic hyperplasia with decreasing complication rates. Technological alternatives such as bipolar and laser treatments may further minimize the risks of this technically difficult procedure.
- Published
- 2006
- Full Text
- View/download PDF
139. Medline: a valuable research tool for the compounding pharmacist.
- Author
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Kuntz R Pharmd
- Abstract
Compounding pharmacists often find themselves on the cutting edge of medical treatment. Prescribers and patients look to compounders for ideas on novel treatments or for more information on standard treatments. Even with the vast supply of information available on the Internet, finding reliable data from trustworhty websites has become increasingly difficult. All too often, an Internet search on a specific medical topic may turn up no dependable material. For complete, science based information about medical topics, the National Library of Medicine's database of medical literature, MEDLINE, is an essential tool for the compounding pharmacist.
- Published
- 2006
140. Stent revascularization for the prevention of cardiovascular and renal events among patients with renal artery stenosis and systolic hypertension: rationale and design of the CORAL trial.
- Author
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Cooper CJ, Murphy TP, Matsumoto A, Steffes M, Cohen DJ, Jaff M, Kuntz R, Jamerson K, Reid D, Rosenfield K, Rundback J, D'Agostino R, Henrich W, and Dworkin L
- Subjects
- Angiotensin II Type 1 Receptor Blockers therapeutic use, Atherosclerosis therapy, Benzimidazoles therapeutic use, Biphenyl Compounds, Cardiovascular Diseases prevention & control, Combined Modality Therapy, Disease Progression, Female, Humans, Hypertension etiology, Hypertension prevention & control, Hypertension, Renovascular etiology, Hypertension, Renovascular physiopathology, Male, Patient Selection, Prospective Studies, Randomized Controlled Trials as Topic, Renal Artery Obstruction complications, Renal Artery Obstruction mortality, Renal Artery Obstruction physiopathology, Research Design, Risk Factors, Tetrazoles therapeutic use, Angioplasty, Balloon, Cardiovascular Diseases etiology, Renal Artery Obstruction therapy, Stents
- Abstract
Background: Atherosclerotic renal artery stenosis is a problem with no consensus on diagnosis or therapy. The consequences of renal ischemia are neuroendocrine activation, hypertension, and renal insufficiency that can potentially result in acceleration of atherosclerosis, further renal dysfunction, myocardial infarction, heart failure, stroke, and death. Whether revascularization improves clinical outcomes when compared with optimum medical therapy is unknown., Methods: CORAL is a randomized clinical trial contrasting optimum medical therapy alone to stenting with optimum medical therapy on a composite cardiovascular and renal end point: cardiovascular or renal death, myocardial infarction, hospitalization for congestive heart failure, stroke, doubling of serum creatinine, and need for renal replacement therapy. The secondary end points evaluate the effectiveness of revascularization in important subgroups of patients and with respect to all-cause mortality, kidney function, renal artery patency, microvascular renal function, and blood pressure control. We will also correlate stenosis severity with longitudinal renal function and determine the value of stenting from the perspectives of quality of life and cost-effectiveness. The primary entry criteria are (1) an atherosclerotic renal stenosis of > or = 60% with a 20 mm Hg systolic pressure gradient or > or = 80% with no gradient necessary and (2) systolic hypertension of > or = 155 mm Hg on > or = 2 antihypertensive medications. Randomization will occur in 1080 subjects. The study has 90% power to detect a 28% reduction in primary end point hazard rate., Conclusions: CORAL represents a unique opportunity to determine the incremental value of stent revascularization, in addition to optimal medical therapy, for the treatment of atherosclerotic renal artery stenosis.
- Published
- 2006
- Full Text
- View/download PDF
141. Does gum chewing ameliorate postoperative ileus? Results of a prospective, randomized, placebo-controlled trial.
- Author
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Matros E, Rocha F, Zinner M, Wang J, Ashley S, Breen E, Soybel D, Shoji B, Burgess A, Bleday R, Kuntz R, and Whang E
- Subjects
- Adolescent, Adult, Aged, Aged, 80 and over, Analysis of Variance, Chi-Square Distribution, Female, Humans, Male, Middle Aged, Placebos, Prospective Studies, Treatment Outcome, Chewing Gum, Colectomy, Ileus prevention & control, Postoperative Complications prevention & control
- Abstract
Background: A preliminary report has been interpreted to suggest that gum chewing reduces duration of postcolectomy ileus., Study Design: We rigorously tested this hypothesis in a prospective, randomized, placebo-controlled study. Patients undergoing open colectomy (n = 66) were randomized to receive 1 of 3 postoperative regimens beginning on postoperative day 1: sips (control, n = 21); sips and accupressure wrist bracelet (placebo, n = 23); and sips and gum chewing (treatment, n = 22). Patients were unaware of which regimen constituted placebo or treatment; end points were assessed by blinded investigators. Power was set a priori at 85% to detect a 0.75-day difference in time to first postoperative passage of flatus between placebo and treatment groups. Groups were compared using the log-rank test., Results: Groups were equivalent with respect to demographic and surgical characteristics. Median times to first postoperative passage of flatus were as follows: sips, 67 hours; bracelet and sips, 72 hours; gum and sips, 60 hours (p = 0.384). There were no significant differences in time to passage of first bowel movement, time until patients were ready for discharge, or time until actual discharge among the three groups. Inpatient and 30-day followup demonstrated no difference in frequency or distribution of postoperative complications., Conclusions: In contrast to findings of a preliminary study, our clinical trial suggests that gum chewing, although safe, does not reduce duration of postcolectomy ileus.
- Published
- 2006
- Full Text
- View/download PDF
142. The story of hospice.
- Author
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Kuntz R
- Published
- 2006
143. Vascular brachytherapy using a beta emitter source in diabetic patients with in-stent restenosis: angiographic and clinical outcomes.
- Author
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Suntharalingam M, Laskey WK, Tantibhedhyangkul W, Lansky A, Teirstein P, Bass T, Silber S, Rutherford B, Wilmer C, Popma JJ, Kuntz R, and Bonan R
- Subjects
- Beta Particles therapeutic use, Coronary Angiography, Coronary Restenosis diagnostic imaging, Diabetic Angiopathies diagnostic imaging, Female, Humans, Male, Middle Aged, Retrospective Studies, Strontium Radioisotopes therapeutic use, Yttrium Radioisotopes therapeutic use, Brachytherapy methods, Coronary Restenosis radiotherapy, Diabetic Angiopathies radiotherapy, Stents
- Abstract
Purpose: The management of diabetic patients with restenosis after percutaneous coronary intervention remains a significant challenge. Diabetic patients remain at significant risk of restenosis despite stent implantation. This retrospective analysis was performed to determine the extent to which vascular brachytherapy improves late clinical and angiographic outcomes in diabetic patients compared to conventional therapy and compared to patients' nondiabetic counterparts., Methods: Pooled data from two studies (START [Stents and Radiation Trial] and START-40 trials) of patients (204 diabetic, 477 nondiabetic) receiving vascular brachytherapy (VBT) with a (90)Sr/(90)Y source after conventional percutaneous coronary intervention for in-stent restenosis comprise the study population. The radiation delivery system used in both studies was the Beta-Cath system. The prescribed dose at 2 mm from the centerline of the source axis was 18.4 Gy or 23 Gy, depending on vessel diameter. The reference vessel diameter, minimal lumen diameter, and percent diameter stenosis were measured before the intervention, at the conclusion of the procedure, and at the 8-month follow-up examination. The Breslow-Day test was used to formally assess the similarity of treatment effect between diabetic and nondiabetic patients., Results: Target lesion and target vessel revascularization rates and angiographic restenosis rates in diabetic and nondiabetic patients treated with beta radiation or placebo were analyzed. Diabetic patients were more likely to have longer and more complex coronary lesions. In-hospital outcomes in diabetic and nondiabetic patients were similar, irrespective of treatment status. At 8 months, patients treated with beta radiation exhibited less target lesion revascularization (diabetic: 10.9% vs. 22.7%, p = 0.02; nondiabetic: 12.8% vs. 22.3%, p = 0.007) and less target vessel revascularization (diabetic: 14.7% vs. 25.3%, p = 0.06; nondiabetic: 16.6% vs. 23.6%, p = 0.06) compared to placebo. In-stent binary angiographic restenosis was lower in irradiated patients (diabetic: 19.4% vs. 37.3% for placebo, p = 0.01; nondiabetic: 12.9% vs. 43% for placebo, p < 0.001). However, restenosis beyond the stent site reduced the impact of VBT, regardless of diabetic status. The magnitude of the treatment effect for target lesion and target vessel revascularization rates was similar between diabetic and nondiabetic patients., Conclusions: Previously published institutional experiences have suggested that diabetic patients benefit from the use of VBT in the management of in-stent restenosis. This analysis now provides direct evidence to support the role of beta radiation VBT in this patient population. Diabetic patients undergoing this therapy are just as likely to benefit from it as their nondiabetic counterparts.
- Published
- 2003
- Full Text
- View/download PDF
144. Sensitization therapy for warts.
- Author
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Kuntz R
- Published
- 2003
145. Treatment of saphenous vein bypass grafts with ultrasound thrombolysis: a randomized study (ATLAS).
- Author
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Singh M, Rosenschein U, Ho KK, Berger PB, Kuntz R, and Holmes DR Jr
- Subjects
- Abciximab, Adult, Aged, Angioplasty, Balloon, Coronary, Antibodies, Monoclonal therapeutic use, Combined Modality Therapy, Coronary Angiography, Coronary Disease diagnosis, Coronary Disease surgery, Female, Follow-Up Studies, Humans, Immunoglobulin Fab Fragments therapeutic use, Male, Middle Aged, Myocardial Infarction epidemiology, Stents, Syndrome, Treatment Outcome, Coronary Artery Bypass, Coronary Disease therapy, Saphenous Vein transplantation, Thrombosis therapy, Ultrasonic Therapy
- Abstract
Background: Percutaneous coronary interventions (PCIs) in saphenous vein grafts (SVGs) with thrombus have a high frequency of distal embolization. Acolysis (therapeutic ultrasound) can break up thrombus in vitro in animal models and humans. Whether this is beneficial during percutaneous SVG interventions is unknown., Methods and Results: We performed a trial of coronary ultrasound thrombolysis in which patients with an acute coronary syndrome undergoing PCI in SVGs were randomly assigned to receive acolysis or abciximab. The primary end point was a successful procedure, defined as final luminal diameter stenosis 30% or less with Thrombolysis In Myocardial Infarction grade 3 flow and freedom from major adverse cardiac events (composite of death, Q-wave, and non-Q-wave myocardial infarction [MI], emergency bypass procedure, disabling stroke, and target lesion revascularization). Of 181 enrolled, 92 received acolysis and 89 abciximab. Angiographic procedural success was achieved in 63% of acolysis patients and 82% of abciximab patients (P=0.008). Incidence of major adverse cardiac events at 30 days was 25% with acolysis and 12% with abciximab (P=0.036), attributable mainly to a greater frequency of non-Q-wave MI with acolysis (19.6% versus 7.9%, P=0.03). The incidence of Q-wave MI was also higher with acolysis (5.4% versus 2.2%, P=nonsignificant). The primary end point was achieved in 53.8% of acolysis patients and 73.1% of abciximab patients (P=0.014)., Conclusions: Use of therapeutic ultrasound in vein graft lesions in patients with acute coronary syndrome had poor angiographic outcome and increased the incidence of acute ischemic complications.
- Published
- 2003
- Full Text
- View/download PDF
146. Development of a virtual flight simulator.
- Author
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Kuntz Rangel R, Guimarães LN, and de Assis Correa F
- Subjects
- Feedback, Humans, Space Flight, User-Computer Interface
- Abstract
We present the development of a flight simulator that allows the user to interact in a created environment by means of virtual reality devices. This environment simulates the sight of a pilot in an airplane cockpit. The environment is projected in a helmet visor and allows the pilot to see inside as well as outside the cockpit. The movement of the airplane is independent of the movement of the pilot's head, which means that the airplane might travel in one direction while the pilot is looking at a 30 degrees angle with respect to the traveled direction. In this environment, the pilot will be able to take off, fly, and land the airplane. So far, the objects in the environment are geometrical figures. This is an ongoing project, and only partial results are available now.
- Published
- 2002
- Full Text
- View/download PDF
147. Treatment of indinavir sulfate induced urolithiasis in HIV-positive patients.
- Author
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Kalaitzis C, Dimitriadis G, Tsatidis T, Kuntz R, Touloupidis S, and Kelidis G
- Subjects
- Adult, Female, Humans, Male, Middle Aged, Urinary Calculi therapy, HIV Protease Inhibitors adverse effects, HIV Seropositivity drug therapy, Indinavir adverse effects, Urinary Calculi chemically induced
- Abstract
Indinavir sulfate is a protease inhibitor used of the treatment of primary HIV infection either as monotherapy or as part of antiretroviral treatment schemes. Approximately 10% of all patients develop urolithiasis with radiolucent stones consisting of indinavir. We present our results of the treatment in 11 HIV positive patients (9 men, 2 women), who developed Indinavir lithiasis after 5-8 months of antiretroviral therapy. Following the initial procedures (spasmoanalgetic drugs, ureteroscopy, double J-stent or nephrostomy), the patients were further treated by increasing diuresis and urinary acidification. All the patients responded well to the treatment, the obstruction was releieved and their renal function was restored to normal.
- Published
- 2002
- Full Text
- View/download PDF
148. Comparison of PRE-dilatation vs direct stenting in coronary treatment using the Medtronic AVE S670 Coronary Stent System (the PREDICT trial).
- Author
-
Baim DS, Flatley M, Caputo R, O'Shaughnessy C, Low R, Fanelli C, Popma J, Fitzgerald P, and Kuntz R
- Subjects
- Coronary Angiography, Humans, Middle Aged, Prospective Studies, Randomized Controlled Trials as Topic, Catheterization, Coronary Restenosis prevention & control, Stents
- Abstract
Current stent delivery systems make primary stenting (stent placement without predilatation) possible, but few controlled trials have been performed to evaluate the success, safety, cost saving, and potential benefit of this approach in reducing late restenosis. The Comparison of PRE-Dilatation Versus Direct Stenting In Coronary Treatment using the Medtronic AVE S670 Coronary Stent System trial was a 399-patient study comparing results with the Medtronic-AVE S670 stent to objective performance criteria based on prior approved stents, with subrandomization to direct stenting versus stenting after balloon predilatation. Overall, results with the S670 stent showed excellent success and safety, with delivery success of 99%, a 14-day adverse event rate of 6.8% (including 6.5% non-Q-wave myocardial infarction), and favorable angiographic (20%) and clinical (12%) restenosis rates. Direct stenting was successful in 92% of cases, with a 99.5% secondary success rate including additional pretreatment of initially unsuccessful direct-stenting attempts, and no increase in complications. There were modest ( approximately 10%) savings in fluoroscopy time, contrast use, and a decrease in angioplasty balloon use (0.6 vs 1.3 balloons/case), but no reduction in clinical or angiographic restenosis. Patients treated later in the study, with a device that had less balloon extension beyond the edges of the stent, had slightly lower angiographic restenosis rates (19% vs 23%). In conclusion, the S670 stent showed excellent overall performance. Although direct stenting was safe and highly successful, it offered only modest cost savings, and no reduction in late restenosis compared with stenting after predilatation.
- Published
- 2001
- Full Text
- View/download PDF
149. SMART: The microstent's ability to limit restenosis trial.
- Author
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Heuser R, Lopez A, Kuntz R, Reduto L, Badger R, Coleman P, Whitlow P, Iannone LA, Safian R, Yeung A, and Moses J
- Subjects
- Aged, Coronary Angiography, Coronary Disease diagnostic imaging, Female, Follow-Up Studies, Graft Occlusion, Vascular diagnostic imaging, Humans, Male, Middle Aged, Prospective Studies, Prosthesis Design, Prosthesis Failure, Recurrence, Angioplasty, Balloon, Coronary instrumentation, Coronary Disease therapy, Graft Occlusion, Vascular prevention & control, Stents
- Abstract
In this randomized, prospective, multicenter trial (n = 661) of patients with de novo or restenotic coronary lesions, 330 patients received the MicroStent(R) II (MSII), and 331 received the Palmaz-Schatz (PS) stent. The short-term procedural success rates were 94.4% and 95.7%, respectively (P = 0.47). The 30-day cumulative incidence of major adverse events [death, myocardial infarction, CVA, target lesion revascularization (TLR)] was 6.4% for the MSII and 4.5% for the PS stent (P = 0.31). The in-stent binary restenosis rate at 6 months was 25.2% for the MSII and 22.1% for the PS stent (P = 0.636). Using Kaplan-Meier estimates, the incidence of clinically driven TLR was 8.9% for the MSII and 9.2% for the PS stent at 180 days; at 270 days, it was 12.8% and 12.1%, respectively (P = 0.83). MSII and the PS stents were comparable with respect to short-term procedural success, complications, and late clinical and angiographic restenosis.
- Published
- 2001
- Full Text
- View/download PDF
150. The PARAGON stent study: a randomized trial of a new martensitic nitinol stent versus the Palmaz-Schatz stent for treatment of complex native coronary arterial lesions.
- Author
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Holmes DR Jr, Lansky A, Kuntz R, Bell MR, Buchbinder M, Fortuna R, O'Shaughnessy CD, and Popma J
- Subjects
- Adult, Aged, Aged, 80 and over, Angioplasty, Balloon, Coronary mortality, Coronary Angiography, Coronary Disease diagnostic imaging, Coronary Disease mortality, Elasticity, Equipment Design, Equipment Failure, Female, Follow-Up Studies, Humans, Male, Middle Aged, Myocardial Infarction etiology, Recurrence, Stents adverse effects, Time Factors, Treatment Outcome, Alloys, Angioplasty, Balloon, Coronary instrumentation, Coronary Disease therapy, Stainless Steel, Stents classification
- Abstract
A new martensitic nitinol stent with improved flexibility and radiopacity was tested to evaluate whether these differences improve initial or long-term outcome. Patients who underwent percutaneous revascularization of a discrete native coronary lesion were randomly assigned to the new stent (PARAGON, n = 349) or to the first-generation Palmaz-Schatz (PS) stent (n = 339). The primary end point was target vessel failure at 6 months (a composite of cardiac or noncardiac death, any infarction in the distribution of the treated vessel, or clinically indicated target vessel revascularization). Secondary end points were, among others, device and procedural success and angiographic restenosis. Mean age was 62 years; diabetes was present in 21% of patients, prior bypass surgery in 6%, and recent infarction in 22% (p = NS for comparison between the 2 randomized arms). The PARAGON stent group had smaller reference vessels (2.97 vs 3.05 mm, p = 0.05), more prior restenosis (8.0% vs 4.5%, p = 0.07), and a longer average stent length (21.3 vs 19.4 mm, p < 0.05). Device success was significantly higher in the PARAGON arm (99.1% vs 94.3%, p < 0.05). Death and infarction at 6-month follow-up were infrequent in both groups. There was no significant difference in death (2.0% vs 1.2%, p = 0.546), but a higher rate of infarction for the PARAGON cohort (9.2% vs 4.7%, p = 0.025). Although target vessel failure (20.3% vs 12.4%, p = 0.005) and target lesion revascularization (12.0% vs 5.9%, p = 0.005) were higher in the PARAGON group, there was no significant difference in 6-month follow-up in in-stent minimal lumen diameter or in the rate of binary angiographic restenosis. Both PARAGON and PS stents are safe and associated with infrequent adverse events. The PARAGON stent can be delivered more frequently than the first-generation PS stent. Although there was no significant difference in in-stent minimal lumen diameter or the frequency of angiographic restenosis, clinical restenosis was more frequent in the PARAGON group.
- Published
- 2000
- Full Text
- View/download PDF
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