71 research outputs found
Radiative Seesaw Mechanism at Weak Scale
We investigate an alternative seesaw mechanism for neutrino mass generation.
Neutrino mass is generated at loop level but the basic concept of usual seesaw
mechanism is kept. One simple model is constructed to show how this mechanism
is realized. The applications of this seesaw mechanism at weak scale to
cosmology and neutrino physics are discussed.Comment: 12 Pages, latex, no figure
Astrophysical Axion Bounds
Axion emission by hot and dense plasmas is a new energy-loss channel for
stars. Observational consequences include a modification of the solar
sound-speed profile, an increase of the solar neutrino flux, a reduction of the
helium-burning lifetime of globular-cluster stars, accelerated white-dwarf
cooling, and a reduction of the supernova SN 1987A neutrino burst duration. We
review and update these arguments and summarize the resulting axion
constraints.Comment: Contribution to Axion volume of Lecture Notes in Physics, 20 pages, 3
figure
Desafio aos requisitos pré-médicos tradicionais como indicadores de sucesso na Escola de Medicina: o Programa Humanidades e Medicina da Escola de Medicina Monte Sinai
A Biomarker-Based Diagnostic Model for Cardiac Dysfunction in Childhood Cancer Survivors
Background: Childhood cancer survivors at risk for heart failure undergo lifelong echocardiographic surveillance. Previous studies reported the limited diagnostic accuracy of N-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) in detecting left ventricular (LV) dysfunction. However, potential enhanced diagnostic accuracy through the combination of biomarkers and clinical characteristics has been suggested. Objectives: The aim of this study was to develop and internally validate a diagnostic model that combines cardiac biomarkers with clinical characteristics for effectively ruling in or ruling out LV dysfunction in childhood cancer survivors. Methods: A multicenter cross-sectional study included 1,334 survivors (median age 34.2 years) and 278 siblings (median age 36.8 years). Logistic regression models were developed and validated through bootstrapping, combining biomarkers with clinical characteristics. Results: Abnormal NT-proBNP levels were observed in 22.1% of survivors compared with 5.4% of siblings, whereas hs-cTnT levels exceeding 10 ng/L were uncommon in both survivors (5.9%) and siblings (5.0%). The diagnostic models demonstrated improvement upon the addition of NT-proBNP and hs-cTnT to clinical characteristics, resulting in an increased C statistic from 0.69 to 0.73 for LV ejection fraction (LVEF) <50% and a more accurate prediction of more severe LV dysfunction, with the C statistic increasing from 0.80 to 0.86 for LVEF <45%. For LVEF <50% (prevalence 10.9%), 16.9% of survivors could be effectively ruled out with high sensitivity (95.4%; 95% CI: 90.4%-99.3%) and negative predictive value (97.5%; 95% CI: 94.6%-99.7%). Similarly, for LVEF <45% (prevalence 3.4%), 53.0% of survivors could be ruled out with moderate to high sensitivity (91.1%; 95% CI: 79.2%-100%) and high negative predictive value (99.4%; 95% CI: 98.7%-100%). Conclusions: The biomarker-based diagnostic model proves effective in ruling out LV dysfunction, offering the potential to minimize unnecessary surveillance echocardiography in childhood cancer survivors. External validation is essential to confirm these findings. (Early Detection of Cardiac Dysfunction in Childhood Cancer Survivors; A DCOG LATER Study; https://onderzoekmetmensen.nl/nl/trial/23641)</p
A Biomarker-Based Diagnostic Model for Cardiac Dysfunction in Childhood Cancer Survivors
Background: Childhood cancer survivors at risk for heart failure undergo lifelong echocardiographic surveillance. Previous studies reported the limited diagnostic accuracy of N-terminal pro–B-type natriuretic peptide (NT-proBNP) and high-sensitivity cardiac troponin T (hs-cTnT) in detecting left ventricular (LV) dysfunction. However, potential enhanced diagnostic accuracy through the combination of biomarkers and clinical characteristics has been suggested. Objectives: The aim of this study was to develop and internally validate a diagnostic model that combines cardiac biomarkers with clinical characteristics for effectively ruling in or ruling out LV dysfunction in childhood cancer survivors. Methods: A multicenter cross-sectional study included 1,334 survivors (median age 34.2 years) and 278 siblings (median age 36.8 years). Logistic regression models were developed and validated through bootstrapping, combining biomarkers with clinical characteristics. Results: Abnormal NT-proBNP levels were observed in 22.1% of survivors compared with 5.4% of siblings, whereas hs-cTnT levels exceeding 10 ng/L were uncommon in both survivors (5.9%) and siblings (5.0%). The diagnostic models demonstrated improvement upon the addition of NT-proBNP and hs-cTnT to clinical characteristics, resulting in an increased C statistic from 0.69 to 0.73 for LV ejection fraction (LVEF) <50% and a more accurate prediction of more severe LV dysfunction, with the C statistic increasing from 0.80 to 0.86 for LVEF <45%. For LVEF <50% (prevalence 10.9%), 16.9% of survivors could be effectively ruled out with high sensitivity (95.4%; 95% CI: 90.4%-99.3%) and negative predictive value (97.5%; 95% CI: 94.6%-99.7%). Similarly, for LVEF <45% (prevalence 3.4%), 53.0% of survivors could be ruled out with moderate to high sensitivity (91.1%; 95% CI: 79.2%-100%) and high negative predictive value (99.4%; 95% CI: 98.7%-100%). Conclusions: The biomarker-based diagnostic model proves effective in ruling out LV dysfunction, offering the potential to minimize unnecessary surveillance echocardiography in childhood cancer survivors. External validation is essential to confirm these findings. (Early Detection of Cardiac Dysfunction in Childhood Cancer Survivors; A DCOG LATER Study; https://onderzoekmetmensen.nl/nl/trial/23641)</p
Presence and utility of electrocardiographic abnormalities in long-term childhood cancer survivors
Background: We assessed the prevalence and diagnostic value of ECG abnormalities for cardiomyopathy surveillance in childhood cancer survivors. Methods: In this cross-sectional study, 1381 survivors (≥5 years) from the Dutch Childhood Cancer Survivor Study part 2 and 272 siblings underwent a long-term follow-up ECG and echocardiography. We compared ECG abnormality prevalences using the Minnesota Code between survivors and siblings, and within biplane left ventricular ejection fraction (LVEF) categories. Among 880 survivors who received anthracycline, mitoxantrone or heart radiotherapy, logistic regression models using least absolute shrinkage and selection operator identified ECG abnormalities associated with three abnormal LVEF categories (<52% in male/<54% in female, <50% and <45%). We assessed the overall contribution of these ECG abnormalities to clinical regression models predicting abnormal LVEF, assuming an absence of systolic dysfunction with a <1% threshold probability. Results: 16% of survivors (52% female, mean age 34.7 years) and 14% of siblings had major ECG abnormalities. ECG abnormalities increased with decreasing LVEF. Integrating selected ECG data into the baseline model significantly improved prediction of sex-specific abnormal LVEF (c-statistic 0.66 vs 0.71), LVEF <50% (0.66 vs 0.76) and LVEF <45% (0.80 vs 0.86). While no survivor met the preset probability threshold in the first two models, the third model used five ECG variables to predict LVEF <45% and was applicable for ruling out (sensitivity 93%, specificity 56%, negative predictive value 99.6%). Calibration and internal validation tests performed well. Conclusion: A clinical prediction model with ECG data (left bundle branch block, left atrial enlargement, left heart axis, Cornell's criteria for left ventricular hypertrophy and heart rate) may aid in ruling out LVEF <45%.</p
Presence and utility of electrocardiographic abnormalities in long-term childhood cancer survivors
Background: We assessed the prevalence and diagnostic value of ECG abnormalities for cardiomyopathy surveillance in childhood cancer survivors. Methods: In this cross-sectional study, 1381 survivors (≥5 years) from the Dutch Childhood Cancer Survivor Study part 2 and 272 siblings underwent a long-term follow-up ECG and echocardiography. We compared ECG abnormality prevalences using the Minnesota Code between survivors and siblings, and within biplane left ventricular ejection fraction (LVEF) categories. Among 880 survivors who received anthracycline, mitoxantrone or heart radiotherapy, logistic regression models using least absolute shrinkage and selection operator identified ECG abnormalities associated with three abnormal LVEF categories (<52% in male/<54% in female, <50% and <45%). We assessed the overall contribution of these ECG abnormalities to clinical regression models predicting abnormal LVEF, assuming an absence of systolic dysfunction with a <1% threshold probability. Results: 16% of survivors (52% female, mean age 34.7 years) and 14% of siblings had major ECG abnormalities. ECG abnormalities increased with decreasing LVEF. Integrating selected ECG data into the baseline model significantly improved prediction of sex-specific abnormal LVEF (c-statistic 0.66 vs 0.71), LVEF <50% (0.66 vs 0.76) and LVEF <45% (0.80 vs 0.86). While no survivor met the preset probability threshold in the first two models, the third model used five ECG variables to predict LVEF <45% and was applicable for ruling out (sensitivity 93%, specificity 56%, negative predictive value 99.6%). Calibration and internal validation tests performed well. Conclusion: A clinical prediction model with ECG data (left bundle branch block, left atrial enlargement, left heart axis, Cornell's criteria for left ventricular hypertrophy and heart rate) may aid in ruling out LVEF <45%.</p
Extensive Cardiac Function Analyses Using Contemporary Echocardiography in Childhood Cancer Survivors:A DCCSS LATER Study
Background: Childhood cancer survivors (CCS) are at risk for cardiotoxicity. Objectives: We sought to assess how cardiac dysfunction measurements in CCS overlap and are differentially influenced by risk factors. Methods: This cross-sectional Dutch Childhood Cancer Survivor Study evaluated echocardiograms of 1,397 ≥5-year CCS and 277 siblings. Of CCS, n = 1,254 received cardiotoxic (anthracyclines/mitoxantrone/radiotherapy involving the heart region [RTheart]) and n = 143 received potentially cardiotoxic (cyclophosphamide, ifosfamide, or vincristine) therapy. We assessed demographic, treatment-related, and traditional cardiovascular risk factors for cardiac dysfunction using multivariable logistic regression. Results: CCS were a median of 26.7 years after diagnosis; 49% were women. Abnormal left ventricular ejection fraction (LVEF) (defined as <52% in men, <54% in women) occurred most commonly in CCS treated with anthracyclines and RTheart combined (38%). Age/sex-specific abnormal global longitudinal strain (GLS) occurred most commonly in CCS treated with RTheart, either with (41%) or without (38%) anthracyclines. Of CCS with normal LVEF, 20.2% showed abnormal GLS. Diastolic dysfunction grade ≥II was rare. Abnormal LVEF was mainly associated with female sex, anthracycline dose, and only in women, RTheart dose. Abnormal GLS was associated with female sex, RTheart dose, diastolic blood pressure, and only in women, anthracycline dose. Cyclophosphamide, ifosfamide, and vincristine were not associated with LVEF or GLS. Compared with siblings, CCS showed higher risk of abnormal LVEF (OR: 2.9; 95% CI: 1.4-6.6) and GLS (OR: 2.1; 95% CI: 1.2-3.7), independent of (potentially) cardiotoxic treatment-related and cardiovascular risk factors. Conclusions: Abnormal LVEF and GLS constitute complementary measures of systolic dysfunction among long-term CCS. Their diagnostic value may differ according to cardiotoxic exposures. Also, CCS have residual, unexplained risk of cardiac dysfunction.</p
Extensive Cardiac Function Analyses Using Contemporary Echocardiography in Childhood Cancer Survivors:A DCCSS LATER Study
Background: Childhood cancer survivors (CCS) are at risk for cardiotoxicity.Objectives: We sought to assess how cardiac dysfunction measurements in CCS overlap and are differentially influenced by risk factors.Methods: This cross-sectional Dutch Childhood Cancer Survivor Study evaluated echocardiograms of 1,397 ≥5-year CCS and 277 siblings. Of CCS, n = 1,254 received cardiotoxic (anthracyclines/mitoxantrone/radiotherapy involving the heart region [RTheart]) and n = 143 received potentially cardiotoxic (cyclophosphamide, ifosfamide, or vincristine) therapy. We assessed demographic, treatment-related, and traditional cardiovascular risk factors for cardiac dysfunction using multivariable logistic regression.Results: CCS were a median of 26.7 years after diagnosis; 49% were women. Abnormal left ventricular ejection fraction (LVEF) (defined as <52% in men, <54% in women) occurred most commonly in CCS treated with anthracyclines and RTheart combined (38%). Age/sex-specific abnormal global longitudinal strain (GLS) occurred most commonly in CCS treated with RTheart, either with (41%) or without (38%) anthracyclines. Of CCS with normal LVEF, 20.2% showed abnormal GLS. Diastolic dysfunction grade ≥II was rare. Abnormal LVEF was mainly associated with female sex, anthracycline dose, and only in women, RTheart dose. Abnormal GLS was associated with female sex, RTheart dose, diastolic blood pressure, and only in women, anthracycline dose. Cyclophosphamide, ifosfamide, and vincristine were not associated with LVEF or GLS. Compared with siblings, CCS showed higher risk of abnormal LVEF (OR: 2.9; 95% CI: 1.4-6.6) and GLS (OR: 2.1; 95% CI: 1.2-3.7), independent of (potentially) cardiotoxic treatment-related and cardiovascular risk factors.Conclusions: Abnormal LVEF and GLS constitute complementary measures of systolic dysfunction among long-term CCS. Their diagnostic value may differ according to cardiotoxic exposures. Also, CCS have residual, unexplained risk of cardiac dysfunction.</p
Evaluation of Heparin Prophylaxis Protocol on Deep Venous Thrombosis and Pulmonary Embolism in Traumatic Brain Injury
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