tbuckley/cabot-search huggingface dataset:
Nonreentrant Mechanisms Underlying Spontaneous Ventricular Arrhythmias in a Model of Nonischemic Heart Failure in Rabbits
Authors: Steven M. Pogwizd
Journal: Circulation (1995)

Background The goal of this study was to define the mechanisms of spontaneously occurring ventricular arrhythmias in the setting of nonischemic heart failure. Methods and Results Three-dimensional cardiac mapping from 232 intramural sites was performed in four rabbits with heart failure induced by combined aortic regurgitation and aortic stenosis and in four control rabbits. During the development of heart failure, serial echocardiographic examination demonstrated a progressive increase in left ventricular (LV) chamber dimensions and a decrease in LV systolic function over 19±2 months. Serial Holter monitoring demonstrated spontaneously occurring premature ventricular complexes (PVCs) (up to 13 000 per day) and couplets in all four rabbits with heart failure, and runs of nonsustained ventricular tachycardia (VT) up to 26 beats long in three. Mapping of spontaneous rhythm was performed for up to 60 minutes. None of the control rabbits demonstrated spontaneous arrhythmias during mapping. Three rabbits with heart failure demonstrated isolated PVCs, and two demonstrated couplets and runs of nonsustained VT up to 4 beats long. The three-dimensional activation sequence of 50 sinus beats (42 from rabbits with heart failure; 8 from control rabbits), 19 PVCs, and 37 beats of couplets and nonsustained VT was determined and the mechanism of arrhythmia defined for all ventricular ectopic beats analyzed. Normal sinus beats from the failing rabbits activated rapidly, with a total activation time of 28±1 ms ( P =.18 versus sinus beats from control hearts, 26±1 ms). Sinus beats preceding PVCs in the rabbits with heart failure activated in a similar fashion, with a total activation time of 26±1 ms. In each case, these PVCs initiated in the subendocardium by a nonreentrant mechanism based on the absence of intervening electrical activity between the termination of the preceding beat and the initiation of the next (225±7 ms), despite the presence of multiple intervening electrode recording sites. Couplets and monomorphic and polymorphic VTs were due to repetitive nonreentrant activation at the same or different subendocardial sites. Total activation time of beats of VT averaged 44±1 ms and did not differ from that of isolated PVCs (43±2 ms, P =.65). Pathological analysis of tissue demonstrated myocardial fiber hypertrophy, degenerative changes, and interstitial fibrosis throughout the failing hearts. Conclusions Spontaneously occurring PVCs, couplets, and VT in a model of nonischemic heart failure are due to nonreentrant mechanisms such as triggered activity or abnormal automaticity. Approaches to the treatment of spontaneously occurring ventricular arrhythmias in patients with nonischemic heart failure should be directed at nonreentrant mechanisms.
Cardiac Actinomycosis
Authors: SAMUEL J. ZOECKLER
Journal: Circulation (1951)

Involvement of the heart by actinomycetes is rare. A case of actinomycosis, with involvement of the chest wall and clinical pericarditis, with recovery, is reported. The organism, Actinomyces bovis, was isolated from the lesion and accurately identified. The literature is reviewed and the modern concepts of pathogenesis and therapy are discussed.
Inflammatory Pseudotumor of the Kidney Mimicking Malignancy on 18F-FDG PET/CT in a Patient With Diabetes and Hepatocellular Carcinoma
Authors: Jae Hoon Lee, Kyeong Geun Lee, Hwon Kyum Park, Soon Young Song, Ji Young Kim, Young Hwan Kim, Yun Young Choi, Ki-Seok Jang, Moon Hyang Park
Journal: Clinical Nuclear Medicine (2012)

Inflammatory pseudotumor (IPT) is a pseudoneoplastic lesion that most commonly involves lung. We report a case of IPT of kidney associated with hepatocellular carcinoma. CT and PET/CT showed the features of renal cell carcinoma. After radical nephrectomy, histologic examination demonstrated acute pyelonephritis associated with papillary necrosis, and IPT involving renal parenchyma and capsule. Although renal IPT is a very rare tumor, awareness of its existence in the differential diagnosis of a renal mass is critical to avoid misdiagnosis. Clinician should carefully consider differential diagnosis and complications associated with acute or chronic pyelonephritis and papillary necrosis in diabetic patients, particularly.
Influenza Vaccination in Renal Transplant Recipients
Authors: Sarbjeet S. Kumar
Journal: JAMA (1978)

Renal transplant recipients receiving immunosuppressive therapy are prone to major pulmonary infections. Development of influenza virus infection may lead to renal allograft damage or rejection. These patients should therefore be protected against influenza viruses by vaccination. A satisfactory antibody response was found in 12 (60%) of 20 renal transplant recipients vaccinated. Among 15 control subjects, the antibody response was satisfactory in all participants (100%). Factors that might play a role in suppression of antibody response include use of immunosuppressive drugs and renal allograft function. Immunization is safe and does not appear to affect renal allograft function.
Call Me 'Mister,' Please
Authors: Don H. Otto
Journal: JAMA (1992)

Our website uses cookies to enhance your experience. By continuing to use our site, or clicking "Continue," you are agreeing to our Cookie Policy | Continue JAMA HomeNew OnlineCurrent IssueFor Authors Publications JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry (1919-1959) Podcasts Clinical Reviews Editors' Summary Medical News Author Interviews More JN Learning / CMESubscribeJobsInstitutions / LibrariansReprints & Permissions Terms of Use | Privacy Policy | Accessibility Statement 2023 American Medical Association. All Rights Reserved Search All JAMA JAMA Network Open JAMA Cardiology JAMA Dermatology JAMA Forum Archive JAMA Health Forum JAMA Internal Medicine JAMA Neurology JAMA Oncology JAMA Ophthalmology JAMA Otolaryngology–Head & Neck Surgery JAMA Pediatrics JAMA Psychiatry JAMA Surgery Archives of Neurology & Psychiatry Input Search Term Sign In Individual Sign In Sign inCreate an Account Access through your institution Sign In Purchase Options: Buy this article Rent this article Subscribe to the JAMA journal
Error and Bias in Determining Exposure Potential of Children at School Locations Using Proximity-Based GIS Techniques
Authors: Paul A. Zandbergen, Joseph W. Green
Journal: Environmental Health Perspectives (2007)

The widespread availability of powerful tools in commercial geographic information system (GIS) software has made address geocoding a widely employed technique in spatial epidemiologic studies.The objective of this study was to determine the effect of the positional error in geocoding on the analysis of exposure to traffic-related air pollution of children at school locations.For a case study of Orange County, Florida, we determined the positional error of geocoding of school locations through comparisons with a parcel database and digital orthophotography. We used four different geocoding techniques for comparison to establish the repeatability of geocoding, and an analysis of proximity to major roads to determine bias and error in environmental exposure assessment.RESULTS INDICATE THAT THE POSITIONAL ERROR IN GEOCODING OF SCHOOLS IS VERY SUBSTANTIAL: We found that the 95% root mean square error was 196 m using street centerlines, 306 m using TIGER roads, and 210 and 235 m for two commercial geocoding firms. We found bias and error in proximity analysis to major roads to be unacceptably large at distances of < 500 m. Bias and error are introduced by lack of positional accuracy and lack of repeatability of geocoding of school locations.These results suggest that typical geocoding is insufficient for fine-scale analysis of school locations and more accurate alternatives need to be considered.
Distribution of blood lead levels in a birth cohort of New Zealanders at age 21.
Authors: J P Fawcett, S M Williams, J L Heydon, T A Walmsley, D B Menkes
Journal: Environmental Health Perspectives (1996)

Little is known about lead exposure in the general population of young adults. In this study, whole blood lead concentration (PbB) was determined in a sample of the Dunedin Multidisciplinary Health and Development Study, a well-documented birth cohort of New Zealanders aged 21 years in 1993-1994. PbB in those who consented to venipuncture at 21 years of age (n = 779; 411 males, 368 females) was compared to PbB for the same cohort at age 11 years. The PbB at age 21 ranged from 0.4 to 56 micrograms/dl with a geometric mean of 4.5 micrograms/dl (95% CI, 4.3-4.7 micrograms/dl). Only three individuals had a PbB above 30 micrograms/dl. Males had significantly higher PbB than females (geometric mean 6.0 vs. 3.2 micrograms/dl; p &lt; 0.0001). The PbB at age 21 was 53% lower than in the same individuals at age 11 (geometric mean 4.8 vs. 10.2 micrograms/dl; p &lt; 0.001; n = 480) and the correlation between corresponding values was weak (r = 0.19; p &lt; 0.001). PbB at age 21 showed significant associations with high risk occupational activities, recreational exposure, domicile close to a main road, smoking, and male sex. Blood lead concentrations continue to fall in New Zealand, but occupational and recreational activities remain a significant source of lead exposure.
Stimulation of Ca-induced Ca release only transiently increases the systolic Ca transient: measurements of Ca fluxes and sarcoplasmic reticulum Ca
Authors: A Trafford
Journal: Cardiovascular Research (1998)

To investigate the effects of stimulating calcium induced Ca release with low concentrations (100-200 microM) of caffeine and, in particular, to study the cellular mechanisms responsible for the transient responses found previously.Experiments were performed on isolated rat ventricular myocytes. Intracellular calcium concentration ([Ca2+]i) was measured with Indo-1, the cells were voltage-clamped with the perforated patch technique and sarcoplasmic reticulum (s.r.) Ca content was estimated from the integral of the caffeine-evoked current.The systolic Ca transient produced by the first depolarization in the presence of caffeine was larger than the control. Over the next few pulses the magnitude of the Ca transient returned to control levels despite the maintained presence of caffeine. The s.r. Ca content was decreased by 9% after one pulse in caffeine and by 21% after several pulses in caffeine. The first pulse in the low concentration of caffeine was followed by an enhanced inward (Na-Ca exchange) current tail indicating increased efflux of calcium from the cell. The extra loss of calcium calculated from the tail current agreed quantitatively with that from the change of s.r. Ca content.These results show that stimulating calcium induced calcium release produces only a transient increase of the systolic Ca transient. This is due to the larger Ca transient decreasing the s.r. Ca content. It is concluded that any agent whose sole mode of action is stimulation of calcium-induced calcium release will not produce a maintained inotropic effect. The consequences of this for the effects of other modulators of calcium induced calcium release are discussed.
Ventilator-associated respiratory infection following lung transplantation
Authors: Jordi Riera, Berta Caralt, Iker López, Salvador Augustin, Antonio Roman, Joan Gavalda, Jordi Rello
Journal: European Respiratory Journal (2014)

The medical records of 170 adult patients who underwent lung transplantation between January 2010 and December 2012 were reviewed to assess the incidence, causative organisms, risk factors and outcomes of post-operative pneumonia and tracheobronchitis. 20 (12%) patients suffered 24 episodes of ventilator-associated pneumonia. The condition was associated with mean increases of 43 days in mechanical ventilation and of 35 days in hospital stay, and significantly higher hospital mortality (OR 9.0, 95% CI 3.2–25.1). Pseudomonas aeruginosa (eight out of 12 patients were multidrug-resistant) was the most common pathogen, followed by Enterobacteriaceae (one out of five patients produced extended-spectrum β-lactamases). Gastroparesis occurred in 55 (32%) patients and was significantly associated with pneumonia (OR 6.2, 95% CI 2.2–17.2). Ventilator-associated tracheobronchitis was associated with a mean increase of 28 days in mechanical ventilation and 30.5 days in hospital stay, but was not associated with higher mortality (OR 1.2, 95% CI 0.4–3.2). Pseudomonas aeruginosa (six out of 16 patients were multidrug resistant) was the most common pathogen, followed by Enterobacteriaceae (three out of 14 patients produced extended-spectrum β-lactamase). Patients with gastroparesis also had more episodes of ventilator-associated tracheobronchitis (40% versus 12%, p&lt;0.001). In conclusion, ventilator-associated pneumonia following lung transplantation increased mortality. Preventing gastroparesis probably decreases the risk of pneumonia and tracheobronchitis. Multidrug-resistant bacteria frequently cause post-lung-transplantation pneumonia and tracheobronchitis.
Early serum HBsAg drop: A strong predictor of sustained virological response to pegylated interferon alfa-2a in HBeAg-negative patients
Authors: Rami Moucari, Vincent Mackiewicz, Olivier Lada, Marie-Pierre Ripault, Corinne Castelnau, Michelle Martinot-Peignoux, Agnes Dauvergne, Tarik Asselah, Nathalie Boyer, Pierre Bedossa, Dominique Valla, Michel Vidaud, Marie-Hélène Nicolas-Chanoine, Patrick Marcellin
Journal: Hepatology (2008)

Pegylated interferon alfa-2a (PEG-IFN) may induce sustained virological response (SVR) in 20% of hepatitis B e antigen (HBeAg)-negative chronic hepatitis B (CHB) patients. In addition, loss of hepatitis B surface antigen (HBsAg) is achieved with a 10% yearly rate after treatment cessation in sustained responders. The aim of this study was to assess on-treatment serum HBsAg kinetics to predict SVR in HBeAg-negative patients treated with PEG-IFN. Forty-eight consecutive patients were treated with PEG-IFN (180 microg/week) for 48 weeks. Serum hepatitis B virus (HBV) DNA (COBAS TaqMan) and HBsAg (Abbott Architect HBsAg QT assay) were assessed at baseline, during treatment (weeks 12, 24, and 48), and during follow-up (weeks 72 and 96). SVR was defined as undetectable serum HBV DNA (<70 copies/mL) 24 weeks after treatment cessation. Twenty-five percent of patients achieved SVR. They were not different from those who failed treatment regarding age, sex, ethnicity, HBV genotype, baseline serum HBV DNA and HBsAg levels, or liver histology. During treatment, serum HBsAg levels decreased only in patients who developed SVR, with mean decreases of 0.8 +/- 0.5, 1.5 +/- 0.6, and 2.1 +/- 1.2 log(10) IU/mL at weeks 12, 24, and 48, respectively. A decrease of 0.5 and 1 log(10) IU/mL in serum HBsAg levels at weeks 12 and 24 of therapy, respectively, had high predictive values of SVR (negative predictive value [NPV] 90%, positive predictive value [PPV] 89% for week 12; NPV 97%, PPV 92% for week 24). HBsAg loss was observed in three patients, all with SVR.Early serum HBsAg drop has high predictive values of SVR to PEG-IFN in HBeAg-negative CHB patients. Serum quantitative HBsAg may be a useful tool to optimize the management of PEG-IFN therapy in these patients.
Model of Chemotherapy-Induced Myelosuppression With Parameter Consistency Across Drugs
Authors: Lena E. Friberg, Anja Henningsson, Hugo Maas, Laurent Nguyen, Mats O. Karlsson
Journal: Journal of Clinical Oncology (2002)

PURPOSE: To develop a semimechanistic pharmacokinetic-pharmacodynamic model describing chemotherapy-induced myelosuppression through drug-specific parameters and system-related parameters, which are common to all drugs. PATIENTS AND METHODS: Patient leukocyte and neutrophil data after administration of docetaxel, paclitaxel, and etoposide were used to develop the model, which was also applied to myelosuppression data from 2′-deoxy-2′-methylidenecytidine (DMDC), irinotecan (CPT-11), and vinflunine administrations. The model consisted of a proliferating compartment that was sensitive to drugs, three transit compartments that represented maturation, and a compartment of circulating blood cells. Three system-related parameters were estimated: baseline, mean transit time, and a feedback parameter. Drug concentration-time profiles affected the proliferation of sensitive cells by either an inhibitory linear model or an inhibitory E max model. To evaluate the model, system-related parameters were fixed to the same values for all drugs, which were based on the results from the estimations, and only drug-specific parameters were estimated. All modeling was performed using NONMEM software. RESULTS: For all investigated drugs, the model successfully described myelosuppression. Consecutive courses and different schedules of administration were also well characterized. Similar system-related parameter estimates were obtained for the different drugs and also for leukocytes compared with neutrophils. In addition, when system-related parameters were fixed, the model well characterized chemotherapy-induced myelosuppression for the different drugs. CONCLUSION: This model predicted myelosuppression after administration of one of several different chemotherapeutic drugs. In addition, with fixed system-related parameters to proposed values, and only drug-related parameters estimated, myelosuppression can be predicted. We propose that this model can be a useful tool in the development of anticancer drugs and therapies.
T-Lymphocyte-Antigen Interactions in Transplant Rejection
Authors: Franklin H. Epstein, Alan M. Krensky, Arthur Weiss, Gerald Crabtree, Mark M. Davis, Peter Parham
Journal: New England Journal of Medicine (1990)

THE replacement of malfunctioning tissues and organs has long been a clinical objective in medicine. Modern transplantation has been made possible by improved clinical care, a better understanding of immunogenetics, cross-matching of antibodies, and the development of several nonspecific immunosuppressive agents, including corticosteroids, azathioprine, antilymphocyte serum, cyclosporine, and monoclonal antibodies. The combination of HLA matching and immunosuppression has greatly improved both graft and patient survival, but several complications persist: infection, hypertension, drug toxicity, recurrence of disease, and psychosocial problems. Identifying more specific modes of immunosuppression therefore remains a challenge for clinical medicine.A thorough understanding of the cellular, biochemical, and . . .
Bronchial Response to Oral Versus Aerosol Metaproterenol in Asthma
Authors: SHIM CHANG
Journal: Annals of Internal Medicine (1980)

We tested the relative efficacy of bronchodilators delivered in aerosol and in oral form in 17 patients with asthma in a double-blind randomized sequence. Treatment consisted of a 20-mg tablet of metaproterenol sulfate, five puffs of metaproterenol aerosol (0.65 mg in each puff for a total of 3.25 mg) administered 20 minutes apart between puffs, a combination of both, and placebos. Bronchodilator response measured by forced expiratory volume in 1 second (FEV1) was significantly greater on the aerosol and the combined regimen than on the oral and placebo regimen. The combined regimen produced a greater bronchodilator response than the aerosol alone, but the difference was not significant. Side effects were frequent after oral medication but absent after the aerosol. Sequential inhalation of aerosol is the preferred route of administration of adrenergic bronchodilator drugs in asthma.
Water and Salt Excretion after Intravenous Salt Load in Hypertensive Subjects
Authors: T. D. ULLMANN, S. H. BLONDHEIM, S. DIKSTEIN, D. BEN-ISHAY
Journal: Circulation (1959)

Intravenous salt-loading tests were performed in 20 hypertensive and 31 normotensive subjects. During the following 5 half-hour collection periods both water and salt excretion by the hypertensive subjects was higher than by the normotensive ones. The diuretic response was much more prolonged and more pronounced than the saluretic response and appears to be a primary response to the salt load, characteristic of the hypertensive state. The increased salt excretion is in part to be explained as the consequence of the increased water excretion. At moderate flow rates a salt-retaining mechanism could be demonstrated which is obscured at the higher rates of urinary flow that usually follow the salt load.
ICU Access and Prospective Payment
Authors: Cory Franklin
Journal: JAMA (1989)

<h3>To the Editor. —</h3> In the article entitled "The Early Effect of Medicare's Prospective Payment System on the Use of Medical Intensive Care Services in Three Community Hospitals,"1 the authors conclude "that within an increasingly cost-conscious hospital environment, ICU [intensive care unit] bed availability decreased and physicians discharged MICU [medical intensive care unit] patients earlier without affecting in-hospital or six-month mortality or severity of illness in the MICU." These conclusions deserve scrutiny. The Prospective Payment System serves basically as a form of implicit rationing imposed on hospitals and physicians. What the current study and other studies the authors cite show is that when ICU beds are rationed within certain limits, physicians can adjust their admitting patterns with no attendant increase in the mortality of ICU patients. This is not the same as demonstrating no detrimental effects when ICU beds are rationed, since those most affected by rationing are the patients
Scientific Change: Historical Studies in the Intellectual, Social and Technical Conditions for Scientific Discovery and Technical Invention, from Antiquity to the Present. Symposium on the History of Science, University of Oxford 9-15 July 1961.
Authors: Lester S. King
Journal: JAMA (1963)

To maintain this international symposium within limits, Dr. Crombie as director tried to keep to a specific theme, namely, the conditions which were responsible for scientific and technical change. Unfortunately, the participants interpreted this much too loosely, so that the collection of studies does not have nearly the unity which a more rigorous direction might have enforced. Twenty-nine communications are divided into major areas, including scientific thinking in antiquity, Chinese science, science and technology in the Middle Ages, and problems in the sociology of science. In modern science, separate parts deal with physical and biological discoveries, and organization of science and technology. As in most congresses, there is fragmentation of topics, and not very much common meeting ground. Some studies conform to the over-all plan, others do not. Of special interest, and serving as an example of effective writing, we can mention specifically the contribution of Edelstein, on motives and
Sex Education in Schools— A Polemic
Authors: F. G. Cummins
Journal: JAMA (1969)

<h3>To the Editor:—</h3> Your editorial on sex education in the schools is appalling. It makes unsupported assertions and draws unfounded conclusions, which have no place in a scientific journal distributed to an intelligent audience. You claim that anyone who opposes this ill-advised program is either a right wing extremist or a dupe. This is a broad inditement which I have not found to be the case. Reasonable individuals have studied this sex education and sensitivity program and have found that it replaces the traditional Judeo-Christian morality with the situational ethic of humanism, leading to a quagmire of problems for the young. It is illogical to believe that a detailed knowledge of sex (including perversion), starting in kindergarten, will somehow reduce the problems of promiscuity. Rather, it produces these very problems, as it has in Sweden, where this program has been compulsory in the schools from kindergarten through the 12th grade.