335 research outputs found
Study of Multiparticle Spikes in Central 4.5A GeV/c C-Cu Collisions
An analysis of local fluctuations, or spikes, is performed for charged
particles produced in central C-Cu collisions at 4.5 GeV//nucleon. The
distributions of spike-centers and the maximum density distributions are
investigated for different narrow pseudorapidity windows to search for
multiparticle dynamical correlations. Two peaks over statistical background are
observed in the spike-center distributions with the structure similar to that
expected from the coherent gluon radiation model and recently found in hadronic
interactions. The dynamical contribution to maximum density fluctuations are
obtained to be hidden by statistical correlations, though behavior of the
distributions shows qualitative agreement with that from the one-dimensional
intermittency model. The observed features of the two different approaches,
coherent vs. stochastic, to the formation of the local dynamical fluctuations
are discussed.Comment: 12 pages, LaTeX, 2 eps fig
Advanced systolic heart failure in undiagnosed cardiac amyloidosis
Introduction: Transthyretin (TTR) amyloidosis is a life-threatening disease characterized by extracellular deposition of hepatocyte derived TTR with hereditary and acquired variants. Although there are over 120 genetic mutations in the (TTR) gene, only a few are responsible for hereditary TTR amyloidosis. The most common mutation in African-Americans is Val142Ile substitution, occurring with a frequency of 3.5%. Accumulation of misfolded TTR within the myocardium results in cardiac restriction and dysfunction, most commonly presenting as heart failure with preserved ejection fraction. Delay of diagnosis is associated with elevated cardiac biomarkers, worsening patient outcomes, and an unfavorable prognosis in a potentially treatable and reversible disease. Tafamidis was approved by the FDA in 2019 and prevents progression of disease by stabilizing misfolded protein fibrils. Liver transplant is the definitive therapy in patients diagnosed at a young age. Our case describes a patient who presented with advanced nonischemic systolic heart failure with subsequent diagnosis of hereditary TTR amyloidosis.
Case: A 72 year old African-American male with a past medical history of worsening nonischemic heart failure diagnosed 20 years ago status post AICD placement in 2016 presented as a transfer with NYHA III systolic heart failure symptoms. His family reported he was experiencing worsening fatigue, generalized weakness, and exertional dyspnea limiting ambulation without assistance for two weeks prior to presentation. Significant bilateral lower extremity edema was also noted. Family history revealed his father and uncle died of heart failure. At the outside hospital, he required dobutamine for persistent hypotension with systolic blood pressure 70-80s. BNP was 2,443 pg/mL, EKG demonstrated low-voltage tracings and echocardiogram showed decreased right ventricular function with pulmonary artery pressure of 46 mmHg, ventricular wall hypertrophy with biatrial enlargement and an ejection fraction of 25%. Dobutamine was weaned after a normal right heart catheterization with recurrence of hypotension to 60/40s with mean arterial pressures in the 40s and norepinephrine infusion was started and subsequently changed to midodrine 5mg three times daily after achieving hemodynamic stability. Genetic testing was obtained, identifying a valine to isoleucine substitution at position 142 (Val142Ile) in the TTR protein. Goals of care were discussed with family who decided to pursue comfort measures, thus the patient was discharged home.
Discussion: TTR cardiac amyloidosis is the hereditary or acquired extracellular deposition of misfolded TTR proteins in the myocardium resulting in restriction and dysfunction, most commonly presenting as heart failure with preserved ejection fraction. The Val142Ile mutation has a frequency of approximately 3.5% in African-Americans and is likely to be underdiagnosed, resulting in an unfavorable prognosis and poor patient outcomes. Subtle clinical and imaging signs include a constellation of ventricular hypertrophy with a low amplitude voltage EKG, biatrial enlargement, heart failure with preserved ejection fraction, and arrhythmias. The most sensitive and specific test for cardiac amyloidosis is 99Tc-pyrophosphate scintigraphy. With advances in genetic testing, it is possible to diagnose hereditary disease early with the potential of reversal with medical therapy and definitive treatment with transplantation. Delay in diagnosis is associated with elevated BNP, troponins, development of systolic heart failure, and fatal arrhythmias. Although most patients present with heart failure with preserved ejection fraction, our patient developed symptoms of advanced systolic heart failure prior to his diagnosis of TTR amyloidosis. As such, cardiac amyloidosis should be considered in patients with worsening heart failure symptoms despite appropriate medical therapy with subtle clinical findings associated with the disease.https://scholarlycommons.henryford.com/merf2020caserpt/1042/thumbnail.jp
On coherent particle production in central 4.3 A Gev/c Mg-Mg collisions
Features of dense groups, or spikes, of negative pions produced in Mg-Mg
collisions at 4.3 GeV/c/nucleon are studied to search for a coherent,
Cerenkov-like, mechanism of particle production process. We investigate the
distributions of spike centers and, for the first time, the energy spectra of
particles in spikes. The spike-center distributions are obtained to exhibit the
structure due to the coherent gluon-jet emission dynamics. This structure is
similar to that observed recently for all-charged-particle spikes in hadronic
and nuclear interactions. The energy distribution within spikes is found to
have a significant peak over the inclusive background, while the inclusive
spectrum shows exponential decrease with two characteristic values of average
kinetic energy. The value of the peak energy and its width are in a good
agreement with those expected for pions produced in a nuclear medium in the
framework of the Cerenkov quantum approach. The peak energy obtained is
consistent with the value of the cross-section maximum observed in coincidence
experiments of nucleon-nucleus interactions.Comment: 9 pages, 3 eps figures, LaTe
Coherent particle production in collisions of relativistic nuclei
Here we give the results of our study of features of dense groups, or spikes,
of particles produced in Mg-Mg and C-Cu collisions at, respectively, 4.3 and
4.5 GeV/c/nucleon aimed to search for a coherent, Cerenkov-like, mechanism of
hadroproduction. We investigate the distributions of spike centers and, for
Mg-Mg interactions, the energy spectra of negatively charged particles in
spikes. The spike-center distributions are obtained to exhibit the structure
expected from coherent gluon-jet emission dynamics. This structure is similar
in both cases considered, namely for all charged and negatively charged
particles, and is also similar to that observed recently for
all-charged-particle spikes in hadronic interactions. The energy distribution
within spikes is found to have a significant peak over the inclusive
background, while the inclusive spectrum shows exponential decrease with two
characteristic values of average kinetic energy. The value of the peak energy
and its width are in a good agreement with those expected for pions produced in
a nuclear medium in the framework of the Cerenkov quantum approach. The peak
energy obtained is consistent with the value of the cross-section maximum
observed in coincidence nucleon-nucleus interaction experiments.Comment: 8 pages, 5 figures. Invited talk presented by E.S. at the 9th
International Workshop on Multiparticle Production: New Frontiers in Soft
Physics and Correlations on the Threshold of the Third Millenium, Turin,
Italy, June 12 - 17, 200
Introducing IR to Medical Students Interested in Primary Care Specialties
Introduction: Over the last several years, interventional radiologists have become increasingly recognized as part of a collaborative healthcare team. At the same time, interventional radiology (IR) is a field poorly represented in many medical school curricula. As IR management options are increasingly incorporated into the clinician’s arsenal, representation during medical education is critical. Several studies have demonstrated that interventional radiology interest group (IRIG) presentations and demonstrations increase knowledge and excitement about the specialty amongst medical students. However, current literature investigating the effect of these presentations on students interested in primary care specialties is lacking. Our study demonstrates that presenting cases specifically targeted toward students interested in primary care specialties increases their knowledge about the role of IR in their future practice.Methods: Case presentations were given to students who attended interest group meetings in family medicine, emergency medicine, pediatrics, and internal medicine. Presentations were developed specifically to consist of cases that are relevant to each interest group’s respective field. The majority of students were in their preclinical years and interested in a variety of non-radiology specialties. Surveys were administered prior to the presentation and following the presentation (7 questions each). All questions were answered on a Likert scale of 1-5 (1—disagree and 5—agree). Questions were centered around general knowledge of IR, the role of IR within their field, and the benefits of IR to their future practice. Descriptive statistics were calculated based on these results.Results: Responses from 81 participants to every question suggested an overall increase in the knowledge of the field of IR following the case presentation. The mean value to the question “I understand the role of IR in my specialty of interest” increased from 2.7 to 3.6 after the presentation. Students’ average response to the question, “I understand some IR procedures” increased 1.3 points on the scale.Conclusions: Medical students are generally not exposed to IR as a specialty despite its expanding role in clinical practice. Increasing medical student familiarity with IR is essential to producing physicians with a broad understanding of the management options at their disposal. Targeted case presentations given to pre-clinical and clerkship-level medical students interested in primary care specialties were effective in increasing understanding of the role of IR in their specialty of interest. Student-led presentations using interest groups as a networking platform are an effective method for forming first impressions and exposing future doctors to the applications of interventional radiology in their practice.https://scholarlycommons.henryford.com/merf2019edu/1001/thumbnail.jp
Diltiazem Induced Bullous Leukocytoclastic Vasculitis
Diltiazem is a calcium ion cellular influx inhibitor approved by the U.S. Food and Drug Administration for the management of hypertension and chronic stable angina. Diltiazem is commonly used off label for chronic ventricular rate control in atrial fibrillation. Very few cases of widespread cutaneous vasculitis have been described in association with diltiazem since 1988. We report on a patient developing diffuse petechiae with overlying palpable purpura and tense bullae in both lower extremities, which progressed to the thighs, buttocks, abdomen, and upper extremities 6 days after starting diltiazem for management of atrial fibrillation. Skin biopsy revealed leukocytoclastic vasculitis.https://scholarlycommons.henryford.com/merf2020caserpt/1009/thumbnail.jp
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