Search Results Heading

MBRLSearchResults

mbrl.module.common.modules.added.book.to.shelf
Title added to your shelf!
View what I already have on My Shelf.
Oops! Something went wrong.
Oops! Something went wrong.
While trying to add the title to your shelf something went wrong :( Kindly try again later!
Are you sure you want to remove the book from the shelf?
Oops! Something went wrong.
Oops! Something went wrong.
While trying to remove the title from your shelf something went wrong :( Kindly try again later!
    Done
    Filters
    Reset
  • Discipline
      Discipline
      Clear All
      Discipline
  • Is Peer Reviewed
      Is Peer Reviewed
      Clear All
      Is Peer Reviewed
  • Item Type
      Item Type
      Clear All
      Item Type
  • Subject
      Subject
      Clear All
      Subject
  • Year
      Year
      Clear All
      From:
      -
      To:
  • More Filters
43 result(s) for "Witteles, Ronald"
Sort by:
Human induced pluripotent stem cell–derived cardiomyocytes recapitulate the predilection of breast cancer patients to doxorubicin-induced cardiotoxicity
The chemotherapeutic agent doxorubicin causes cardiac injury in a subset of cancer patients. This variable clinical response to doxorubicin treatment can be recapitulated in vitro by using cardiomyocytes derived from patient-specific induced pluripotent cells. Doxorubicin is an anthracycline chemotherapy agent effective in treating a wide range of malignancies, but it causes a dose-related cardiotoxicity that can lead to heart failure in a subset of patients. At present, it is not possible to predict which patients will be affected by doxorubicin-induced cardiotoxicity (DIC). Here we demonstrate that patient-specific human induced pluripotent stem cell–derived cardiomyocytes (hiPSC-CMs) can recapitulate the predilection to DIC of individual patients at the cellular level. hiPSC-CMs derived from individuals with breast cancer who experienced DIC were consistently more sensitive to doxorubicin toxicity than hiPSC-CMs from patients who did not experience DIC, with decreased cell viability, impaired mitochondrial and metabolic function, impaired calcium handling, decreased antioxidant pathway activity, and increased reactive oxygen species production. Taken together, our data indicate that hiPSC-CMs are a suitable platform to identify and characterize the genetic basis and molecular mechanisms of DIC.
AG10 inhibits amyloidogenesis and cellular toxicity of the familial amyloid cardiomyopathy-associated V122I transthyretin
The misassembly of soluble proteins into toxic aggregates, including amyloid fibrils, underlies a large number of human degenerative diseases. Cardiac amyloidoses, which are most commonly caused by aggregation of Ig light chains or transthyretin (TTR) in the cardiac interstitium and conducting system, represent an important and often underdiagnosed cause of heart failure. Two types of TTR-associated amyloid cardiomyopathies are clinically important. The Val122Ile (V122I) mutation, which alters the kinetic stability of TTR and affects 3% to 4% of African American subjects, can lead to development of familial amyloid cardiomyopathy. In addition, aggregation of WT TTR in individuals older than age 65 y causes senile systemic amyloidosis. TTR-mediated amyloid cardiomyopathies are chronic and progressive conditions that lead to arrhythmias, biventricular heart failure, and death. As no Food and Drug Administration-approved drugs are currently available for treatment of these diseases, the development of therapeutic agents that prevent TTR-mediated cardiotoxicity is desired. Here, we report the development of AG10, a potent and selective kinetic stabilizer of TTR. AG10 prevents dissociation of V122I-TTR in serum samples obtained from patients with familial amyloid cardiomyopathy. In contrast to other TTR stabilizers currently in clinical trials, AG10 stabilizes V122I- and WT-TTR equally well and also exceeds their efficacy to stabilize WT and mutant TTR in whole serum. Crystallographic studies of AG10 bound to V122I-TTR give valuable insights into how AG10 achieves such effective kinetic stabilization of TTR, which will also aid in designing better TTR stabilizers. The oral bioavailability of AG10, combined with additional desirable drug-like features, makes it a very promising candidate to treat TTR amyloid cardiomyopathy.
Comparative arrhythmia patterns among patients on tyrosine kinase inhibitors
BackgroundTyrosine kinase inhibitors (TKIs) are widely used in the treatment of hematologic malignancies. Limited studies have shown an association between treatment-limiting arrhythmias and TKI, particularly ibrutinib, a Bruton’s tyrosine kinase (BTK) inhibitor. We sought to comprehensively assess the arrhythmia burden in patients receiving ibrutinib vs non-BTK TKI vs non-TKI therapies.MethodsWe performed a retrospective analysis of consecutive patients who received long-term cardiac event monitors while on ibrutinib, non-BTK TKIs, or non-TKI therapy for a hematologic malignancy between 2014 and 2022.ResultsOne hundred ninety-three patients with hematologic malignancies were included (ibrutinib = 72, non-BTK TKI = 46, non-TKI therapy = 75). The average duration of TKI therapy was 32 months in the ibrutinib group vs 64 months in the non-BTK TKI group (p = 0.003). The ibrutinib group had a higher prevalence of atrial fibrillation (n = 32 [44%]) compared to the non-BTK TKI (n = 7 [15%], p = 0.001) and non-TKI (n = 15 [20%], p = 0.002) groups. Similarly, the prevalence of non-sustained ventricular tachycardia was higher in the ibrutinib group (n = 31, 43%) than the non-BTK TKI (n = 8 [17%], p = 0.004) and non-TKI groups (n = 20 [27%], p = 0.04). TKI therapy was held in 25% (n = 18) of patients on ibrutinib vs 4% (n = 2) on non-BTK TKIs (p = 0.005) secondary to arrhythmias.ConclusionsIn this large retrospective analysis of patients with hematologic malignancies, patients receiving ibrutinib had a higher prevalence of atrial and ventricular arrhythmias compared to those receiving other TKI, with a higher rate of treatment interruption due to arrhythmias.
Tyrosine kinase inhibitor–associated ventricular arrhythmias: a case series and review of literature
Background Tyrosine kinase inhibitors (TKIs) have been increasingly used as first-line therapy in hematologic and solid-organ malignancies. Multiple TKIs have been linked with the development of cardiovascular complications, especially atrial arrhythmias, but data on ventricular arrhythmias (VAs) is scarce. Methods Herein we describe five detailed cases of VAs related to TKI use in patients with varied baseline cardiovascular risk factors between 2019 and 2022 at three centers. Individual chart review was conducted retrospectively. Results Patient ages ranged from 43 to 83 years. Three patients were on Bruton’s TKI (2 ibrutinib and 1 zanubrutinib) at the time of VAs; other TKIs involved were afatinib and dasatinib. Three patients had a high burden of non-sustained ventricular tachycardia (NSVT) requiring interventions, whereas two patients had sustained VAs. While all patients in our case series had significant improvement in VA burden after TKI cessation, two patients required new long-term antiarrhythmic drug therapy, and one had an implantable defibrillator cardioverter (ICD) placed due to persistent VAs after cessation of TKI therapy. One patient reinitiated TKI therapy after control of arrhythmia was achieved with antiarrhythmic drug therapy. Conclusions Given the expanding long-term use of TKIs among a growing population of cancer patients, it is critical to acknowledge the association of TKIs with cardiovascular complications such as VAs, to characterize those at risk, and deploy preventive and therapeutic measures to avoid such complications and interference with oncologic therapy. Further efforts are warranted to develop monitoring protocols and optimal treatment strategies for TKI-induced VAs.
A Retrospective Analysis of Medical Student Performance Evaluations, 2014–2020: Recommend with Reservations
BACKGROUNDThe Medical Student Performance Evaluations (MSPE) is a cornerstone of residency applications. Little is known regarding adherence to Association of American Medical Colleges (AAMC) MSPE recommendations and longitudinal changes in MSPE content.OBJECTIVESEvaluate current MSPE quality and longitudinal changes in MSPE and grading practices.DESIGNRetrospective analysis.PARTICIPANTSStudents from all Liaison Committee on Medical Education (LCME)-accredited medical schools from which the Stanford University Internal Medicine residency program received applications between 2014–2015 and 2019–2020.MAIN MEASURESInclusion of key words to describe applicant performance and metrics thereof, including distribution among students and key word assignment explanation; inclusion of clerkship grades, grade distributions, and grade composition; and evidence of grade inflation over time.KEY RESULTSMSPE comprehensiveness varied substantially among the 149 schools analyzed. In total, 25% of schools provided complete information consistent with AAMC recommendations regarding key word/categorization of medical students and clerkship grades in 2019–2020. Seventy-seven distinct key word terms appeared across the 139 schools examined in 2019–2020. Grading practices markedly varied, with 2–83% of students receiving the top internal medicine clerkship grade depending on the year and school. Individual schools frequently changed key word and grading practices, with 33% and 18% of schools starting and/or stopping use of key words and grades, respectively. Significant grade inflation occurred over the 6-year study period, with an average 14% relative increase in the proportion of students receiving top clerkship grades.CONCLUSIONSA minority of schools complies with AAMC MSPE guidelines, and MSPEs are inconsistent across time and schools. These practices may impair evaluation of students within and between schools.
Racial and Ethnic Disparities in Transthyretin Cardiac Amyloidosis
Purpose of Review Transthyretin amyloid cardiomyopathy (ATTR-CM) is a life-threatening disease that disproportionately affects older adults and people of African descent. This review discusses current knowledge regarding racial and ethnic disparities in the diagnosis and management of ATTR-CM. Recent Findings Historically, ATTR-CM was thought to be a rare cause of heart failure. Recent evidence has shown that ATTR-CM is more common among older adults, men, and people of African descent. In addition, significant geographic variation exists in the identification of amyloid cardiomyopathy. Despite the high burden of ATTR-CM among Black individuals, most clinical data for ATTR-CM are from North America and Europe. Moreover, only a minority of clinical trial participants thus far have been Black patients. In addition to racial differences, socioeconomic disparities may be further compounded by the potentially prohibitive cost and limited accessibility of disease-modifying ATTR therapies. Summary ATTR-CM is an important cause of heart failure that disproportionately affects people of African descent. Efforts to promote earlier identification of ATTR-CM in general practice will likely improve clinical outcomes for all groups. Future trials should strive to enroll a higher proportion of Black patients. Furthermore, enhanced efforts are warranted to improve treatment accessibility among racial and ethnic minority groups that may be more likely to be affected by ATTR-CM.
Capecitabine-Induced Chest Pain Relieved by Diltiazem
Five patients with primary colorectal adenocarcinoma or anal squamous cell carcinoma were started on a 2-weeks-on, 1-week-off capecitabine dosing regimen in addition to other chemotherapeutic agents and/or radiation. Within the first few doses, patients experienced chest pain and/or dyspnea at rest or with exertion. Acute electrocardiographic findings suggestive of ischemia were found in some cases at initial presentation, and 1 patient had troponin elevation consistent with an acute ST-segment elevation myocardial infarction. Subsequent ischemia evaluations were not suggestive of clinically significant coronary artery disease. All patients experienced immediate and sustained relief from chest pain after discontinuation of capecitabine and were able to successfully tolerate retreatment using a novel management strategy based on secondary prophylaxis with diltiazem. In conclusion, guidelines for the evaluation of and therapy for capecitabine-induced chest pain are proposed.
Emerging Therapies for Transthyretin Cardiac Amyloidosis
Purpose of review Transthyretin cardiac amyloidosis is an underdiagnosed, undertreated disease which is associated with significant morbidity and mortality. This review will discuss the recent advancements in novel therapies for transthyretin amyloidosis. Recent findings In recent phase 3 clinical trials, transthyretin stabilizers (tafamidis) and transthyretin silencers (patisiran and inotersen) have proven to be effective therapies for various forms of transthyretin amyloidosis. Summary Understanding the recent and upcoming clinical trials for transthyretin amyloidosis will be important for improving the management of this challenging disease.
Advances in the Diagnosis and Management of Transthyretin Amyloid Cardiomyopathy
Purpose of review Transthyretin amyloid cardiomyopathy (ATTR-CM) is a disease with high morbidity and mortality. This disease is significantly underdiagnosed and is more common than previously appreciated, particularly among older adults and people of African descent. This review discusses recent advances in the diagnosis and treatment for ATTR-CM. Recent findings Historically, ATTR-CM was diagnosed via endomyocardial biopsy, a resource-intensive and invasive approach. However, in most cases, ATTR-CM can now be diagnosed non-invasively using bone tracer cardiac scintigraphy, which may facilitate earlier diagnosis. In recent clinical trials, a transthyretin stabilizer (tafamidis) and transthyretin gene silencers (patisiran and inotersen) have emerged as effective ATTR amyloidosis therapies and have been approved for use in the USA and many other countries. Summary ATTR-CM is now recognized as an important cause of heart failure. Approaches to the diagnosis and treatment of ATTR-CM are rapidly evolving. Now, more than ever, there are opportunities to improve clinical care of patients with this challenging disease.
Radiation-Induced Heart Disease: An Under-Recognized Entity?
Opinion statement Radiation-induced heart disease (RIHD) represents a spectrum of cardiovascular disease in patients who have undergone mediastinal, thoracic, or breast radiotherapy (RT). RIHD may involve any cardiac structure and is a major cause of morbidity and mortality in cancer survivors. While large cohort studies have demonstrated that symptomatic RIHD is a common late finding in this population, the incidence of asymptomatic disease is likely to be even higher. Long-term follow-up with regular screening for RIHD plays an important role in the management of cancer survivors who have undergone RT. Aggressive modification of traditional cardiovascular risk factors such as hypertension, dyslipidemia, and cigarette smoking is essential in patients at risk for RIHD, as these have been shown to potentiate the risks of radiation. In patients with symptomatic RIHD, medical and/or percutaneous therapies are often preferable to surgical interventions in view of the increased surgical risk associated with radiation damage to surrounding tissues. Percutaneous revascularization should generally be favored over surgical revascularization. Transcatheter valve replacements have not been widely used in this population but may offer an alternative to high-risk surgical valve procedures. Pericardiectomy is usually associated with extremely poor short-term and long-term outcomes in patients with RIHD and should be avoided in most cases. Heart transplantation is also higher risk in patients with RIHD than in patients with other etiologies of heart failure, but may be considered in young patients without other comorbidities.