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Dive into the research topics where Nancy Sweeters is active.

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Featured researches published by Nancy Sweeters.


Haematologica | 2013

A randomized, placebo-controlled trial of arginine therapy for the treatment of children with sickle cell disease hospitalized with vaso-occlusive pain episodes

Claudia R. Morris; Frans A. Kuypers; Lisa Lavrisha; Michael Ansari; Nancy Sweeters; Melinee Stewart; Ginny Gildengorin; Lynne Neumayr; Elliott Vichinsky

Painful episodes of vaso-occlusion are the leading cause of hospitalizations and emergency department visits in sickle cell disease, and are associated with increased mortality. Low nitric oxide bioavailability contributes to vasculopathy in sickle cell disease. Since arginine is the obligate substrate for nitric oxide production, and an acute deficiency is associated with pain, we hypothesized that arginine may be a beneficial treatment for pain related to sickle cell disease. Thirty-eight children with sickle cell disease hospitalized for 56 episodes of pain were randomized into this double-blinded placebo-controlled trial. Patients received L-arginine (100 mg/kg tid) or placebo for 5 days or until discharge. A significant reduction in total parenteral opioid use by 54% (1.9±2.0 mg/kg versus 4.1±4.1 mg/kg, P=0.02) and lower pain scores at discharge (1.9±2.4 versus 3.9±2.9, P=0.01) were observed in the treatment arm compared to the placebo one. There was no significant difference in hospital length of stay (4.1±01.8 versus 4.8±2.5 days, P=0.34), although a trend favored the arginine arm, and total opioid use was strongly correlated with the duration of the admission (r=0.86, P<0.0001). No drug-related adverse events were observed. Arginine therapy represents a novel intervention for painful vaso-occlusive episodes. A reduction of narcotic use by >50% is remarkable. Arginine is a safe and inexpensive intervention with narcotic-sparing effects that may be a beneficial adjunct to standard therapy for sickle cell-related pain in children. A large multi-center trial is warranted in order to confirm these observations.


British Journal of Haematology | 2005

Fetal haemoglobin augmentation in E/β0 thalassaemia: clinical and haematological outcome

Sylvia T. Singer; Frans A. Kuypers; Nancy F. Olivieri; D. J. Weatherall; Robert Mignacca; Thomas D. Coates; Sally C. Davies; Nancy Sweeters; Elliott Vichinsky

Patients with E/β0 thalassaemia, the most common haemoglobinopathy in many Asian countries, might benefit from drugs that increase fetal and total haemoglobin and thereby decrease the need for transfusions. The long‐term clinical efficacy and safety of such therapy is unknown, limiting its use in countries where resources for safe and regular transfusion are scarce. In this study, 45 patients were treated with hydroxyurea (18–20 mg/kg) for 24 ± 9 months, hydroxyurea with sodium phenyl butyrate (n = 8) and hydroxyurea with erythropoietin (n = 9), each for ∼6 months, and followed for 3 years from study exit. Hydroxyurea had minimal toxicity, resulted in a mean 1·3 g/dl steady‐state increase in haemoglobin in 40% of patients, and a milder response (≤1 g/dl) in the others. Baseline haemoglobin F was significantly associated with an increase in haemoglobin (P < 0·001). Combined treatment with erythropoietin benefited selected patients, but the addition of sodium phenyl butyrate had no effect. Of the 27/45 patients who discontinued regular transfusions before the study, 13 remained transfusion independent during long‐term follow‐up, 6/13 continued hydroxyurea. Hydroxyurea moderately increased steady‐state haemoglobin in a sub‐group of E/β0 thalassaemia patients and can be considered for patients with intermediate severity disease, thus delaying or avoiding the need for life‐long transfusions. Continuous monitoring of toxicity and growth is required.


Blood | 2011

Risk factors and mortality associated with an elevated tricuspid regurgitant jet velocity measured by Doppler-echocardiography in thalassemia: a Thalassemia Clinical Research Network report

Claudia R. Morris; Hae-Young Kim; Felicia Trachtenberg; John C. Wood; Charles T. Quinn; Nancy Sweeters; Janet L. Kwiatkowski; Alexis A. Thompson; Patricia J. Giardina; Jeanne Boudreaux; Nancy F. Olivieri; John B. Porter; Ellis J. Neufeld; Elliott Vichinsky

An elevated tricuspid regurgitant jet velocity (TRV) is associated with hemolysis and early mortality in sickle cell disease, yet risk factors, clinical parameters, and mortality associated with this biomarker in thalassemia are poorly defined. This report summarizes the prevalence of an elevated TRV in 325 patients screened by Doppler echocardiography in the Thalassemia Clinical Research Network. A documented TRV was reported in 148 of 325 (46%) of patients. Average age was 25.9 years (range, 5-56 years) and 97% were transfusion-dependent. Mean TRV was 2.3 ± 0.4 m/s (range, 0.2-3.5 m/s). An abnormal TRV ≥ 2.5 m/s was identified in 49 of 148 (33%) of patients with a documented TRV, 5% (8/148), with a TRV ≥ 3.0 m/s, suggesting significant PH risk. Older age was strongly associated with a high TRV; however, 16% of children had a TRV ≥ 2.5 m/s. A history of splenectomy, hepatitis C, smoking, or high white blood cell count was associated with TRV elevation. In summary, an elevated TRV is noted in one-third of transfusion-dependent thalassemia patients with a documented value and develops in both children and adults. Age, splenectomy, hepatitis C, and smoking are significant univariate risk factors, with splenectomy surfacing as the dominant risk factor over time. Mortality was low in this cohort. Prospective longitudinal studies are needed. This study is registered at http://www.clinicaltrials.gov as NCT00661804.


Blood Cells Molecules and Diseases | 2013

Combined chelation therapy with deferasirox and deferoxamine in thalassemia.

Ashutosh Lal; John B. Porter; Nancy Sweeters; Vivian Ng; Patricia Evans; Lynne Neumayr; Gregory Kurio; Paul Harmatz; Elliott Vichinsky

Iron overload is the primary cause of mortality and morbidity in thalassemia major despite advances in chelation therapy. We performed a pilot clinical trial to evaluate the safety and efficacy of combined therapy with deferasirox (DFX, 20-30 mg/kg daily) and deferoxamine (DFO, 35-50mg/kg on 3-7 days/week) in 22 patients with persistent iron overload or organ damage. In the 18 subjects completing 12 months of therapy, median liver iron concentration decreased by 31% from 17.4 mg/g (range 3.9-38.2mg/g) to 12.0mg/g (range 0.96-26.7 mg/g, p<0.001). Median ferritin decreased by 24% from 2465 ng/mL (range 1110-10,700 ng/mL) to 1875 ng/mL (range 421-5800 ng/mL, p=0.002). All 6 subjects with elevated myocardial iron showed improvement in MRI T2* (p=0.031). The mean±S.E. plasma non-transferrin-bound iron (NTBI) declined from 3.10±0.25μM to 2.15±0.29μM (p=0.028). The administration of DFX during infusion of DFO further lowered NTBI (-0.28±0.08 μM, p=0.004) and labile plasma iron (LPI, -0.03±0.01 μM, p=0.006). The simultaneous administration of DFO and DFX rapidly reduced systemic and myocardial iron, and provided an excellent control of the toxic labile plasma iron species without an increase in toxicity.


Haematologica | 2013

Sildenafil therapy in thalassemia patients with Doppler-defined risk of pulmonary hypertension

Claudia R. Morris; Hae-Young Kim; John C. Wood; John B. Porter; Elizabeth S. Klings; Felicia Trachtenberg; Nancy Sweeters; Nancy F. Olivieri; Janet L. Kwiatkowski; Lisa Virzi; Sylvia T. Singer; Ali Taher; Ellis J. Neufeld; Alexis A. Thompson; Vandana Sachdev; Sandra Larkin; Jung H. Suh; Frans A. Kuypers; Elliott Vichinsky

Pulmonary hypertension is a common but often overlooked complication associated with thalassemia syndromes. There are limited data on the safety and efficacy of selective pulmonary vasodilators in this at-risk population. We, therefore, designed a 12-week, open-label, phase 1/2, pilot-scale, proof-of-principle trial of sildenafil therapy in 10 patients with β-thalassemia and at increased risk of pulmonary hypertension based on an elevated tricuspid regurgitant jet velocity >2.5 m/s on Doppler-echocardiography. Variables compared at baseline and after 12 weeks of sildenafil treatment included Doppler-echocardiographic parameters, 6-minute walked distance, Borg Dyspnea Score, New York Heart Association functional class, pulmonary function, and laboratory parameters. Treatment with sildenafil resulted in a significant decrease in tricuspid regurgitant jet velocity by 13.3% (3.0±0.7 versus 2.6±0.5 m/s, P=0.04), improved left ventricular end systolic/diastolic volume, and a trend towards a improved New York Heart Association functional class. No significant change in 6-minute walked distance was noted. Sildenafil was well tolerated, although minor expected adverse events were commonly reported. The total dose of sildenafil (mg) was strongly correlated with percent change in nitric oxide metabolite concentration in the plasma (ρ=0.80, P=0.01). There were also significant increases in plasma and erythrocyte arginine concentrations. Our study suggests that sildenafil is safe and may improve pulmonary hemodynamics in patients at risk of pulmonary hypertension; however, it was not demonstrated to improve the distance walked in 6 minutes. Clinical trials are needed to identify the best treatment strategy for pulmonary hypertension in patients with β-thalassemia. (clinicaltrials.gov identifier: NCT00872170)


British Journal of Haematology | 2011

Darbepoetin alfa for the treatment of anaemia in alpha- or beta- thalassaemia intermedia syndromes

Sylvia T. Singer; Elliott Vichinsky; Nancy Sweeters; Eliezer A. Rachmilewitz

Alter, B.P. (2003) Cancer in Fanconi anemia, 1927– 2001. Cancer, 97, 425–440. Baron, F., Sybert, V.P. & Andrews, R.G. (1989) Cutaneous and extracutaneous neutrophilic infiltrates (Sweet syndrome) in three patients with Fanconi anemia. Journal of Pediatrics, 115, 726–729. Briot, D., Mace-Aime, G., Subra, F. & Rosselli, F. (2008) Aberrant activation of stress-response pathways leads to TNF-alpha oversecretion in Fanconi anemia. Blood, 111, 1913–1923. Buck, T., Gonzalez, L.M., Lambert, W.C. & Schwartz, R.A. (2008) Sweet’s syndrome with hematologic disorders: a review and reappraisal. International Journal of Dermatology, 47, 775–782. Chatham-Stephens, K., Devere, T., Guzman-Cottrill, J. & Kurre, P. (2008) Metachronous manifestations of Sweet’s syndrome in a neutropenic patient with Fanconi anemia. Pediatric Blood & Cancer, 51, 128–130. Guhl, G. & Garcia-Diez, A. (2008) Subcutaneous sweet syndrome. Dermatologic Clinics, 26, 541–551. viii–ix. Hospach, T., von den Driesch, P. & Dannecker, G.E. (2009) Acute febrile neutrophilic dermatosis (Sweet’s syndrome) in childhood and adolescence: two new patients and review of the literature on associated diseases. European Journal of Pediatrics, 168, 1–9. McDermott, M.B., Corbally, M.T. & O’ Marcaigh, A.S. (2001) Extracutaneous Sweet syndrome involving the gastrointestinal tract in a patient with Fanconi anemia. Journal of Pediatric Hematology/oncology, 23, 59–62. Vardiman, J.W., Thiele, J., Arber, D.A., Brunning, R.D., Borowitz, M.J., Porwit, A., Harris, N.L., Le Beau, M.M., Hellström-Lindberg, E., Tefferi, A. & Bloomfield, C.D. (2009) The 2008 revision of the World Health Organization (WHO) classification of myeloid neoplasms and acute leukemia: rationale and important changes. Blood, 114, 937–951. Vignon-Pennamen, M.D., Juillard, C., Rybojad, M., Wallach, D., Daniel, M.T., Morel, P., Verola, O. & Janin, A. (2006) Chronic recurrent lymphocytic Sweet syndrome as a predictive marker of myelodysplasia: a report of 9 cases. Archives of Dermatology, 142, 1170–1176.


Annals of the New York Academy of Sciences | 2010

Fertility potential in thalassemia major women: current findings and future diagnostic tools

Sylvia T. Singer; Nancy Sweeters; Olivia Vega; Annie Higa; Elliott Vichinsky; Marcelle I. Cedars

Preserving fertility, preventing early menopause, and predicting reproductive ability have become crucial for many adult thalassemia major females. Luteinizing hormone/follicle‐stimulating hormone (LH/FSH) and estradiol, commonly used for assessment of fertility potential in thalassemia, have a poor predictive value. Current reproductive practice uses markers of ovarian reserve testing, which were not yet studied in thalassemia women. We explored the relationship between liver iron concentration (LIC) and fertility status in 26 females (mean 30 years old). Seventeen (65%) of them experienced primary or secondary amenorrhea. Levels of LH/FSH and estradiol were low or undetectable in 48% and 35% of patients, respectively and did not correlate with age, presence of amenorrhea, and LIC. This further addresses the need for utilization of current available methods for assessment of fertility capacity in thalassemia, which will also allow future correlation with pituitary iron measures by MRI as well as early intervention for fertility preservation.


American Journal of Hematology | 2008

Hydroxycarbamide-induced changes in E/beta thalassemia red blood cells.

Sylvia T. Singer; Elliott Vichinsky; Sandra Larkin; Nancy F. Olivieri; Nancy Sweeters; Frans A. Kuypers

In thalassemia, fetal hemoglobin (HbF) augmentation with hydroxycarbamide (also known as hydroxyurea) is not always successful. The expected parallel effects on red cell (RBC) membrane deformability, cell hydration, and membrane phospholipid organization, all important for extending RBC life span and increasing Hb, have been infrequently examined. We analyzed these characteristics in 15 nontransfused E/β0 thalassemia patients treated with HU (mean 10.2 months). Membrane deformability and cell hydration mildly improved in association with increased HbF levels approaching statistical significance (r = 0.51, P = 0.06). All measures improved considerably in splenctomized patients. These findings underscore the disappointing results of hydroxyurea treatment in clinical trials and the importance of examining the effect on RBC characteristics for the development and understanding of HbF‐enhancing agents. Am. J. Hematol., 2008.


Annals of the New York Academy of Sciences | 2005

Single and Combination Drug Therapy for Fetal Hemoglobin Augmentation in Hemoglobin E‐β0‐Thalassemia: Considerations for Treatment

Sylvia T. Singer; Frans A. Kuypers; Nancy F. Olivieri; D. J. Weatherall; Robert Mignacca; Thomas D. Coates; Sally C. Davies; Nancy Sweeters; Elliott Vichinsky

Abstract: Patients with hemoglobin E (Hb E)‐β0‐thalassemia, one of the most common hemoglobinopathies worldwide, could benefit from drugs that increase fetal and total hemoglobin levels and thereby decrease the need for transfusions. The long‐term clinical outcome of such therapy, its hematologic effects, and which patients are likely to benefit from treatment are unknown. Consequently, the use of such drugs for Hb E‐β0‐thalassemia is limited, and countries where resources for safe and regular transfusion are scarce cannot benefit from them. In a multicenter trial of 42 patients treated with hydroxyurea for two years, almost half the patients demonstrated a significant increase in steady‐state hemoglobin level. Drug toxicity was minimal. Combined treatment of hydroxyurea with erythropoietin benefited selected patients, but the addition of sodium phenyl butyrate was ineffective. After 5 years of follow‐up, a subset of patients remained off transfusions. Hydroxyurea should be considered for a subset of Hb E‐β0‐thalassemia patients.


Pediatric Blood & Cancer | 2010

Education and Employment Status of Children and Adults with Thalassemia in North America

Zahra Pakbaz; Marsha Treadwell; Hae-Young Kim; Felicia Trachtenberg; Nagina Parmar; Janet L. Kwiatkowski; Melody J. Cunningham; Marie Martin; Nancy Sweeters; Ellis J. Neufeld; Patricia J. Giardina; Nancy F. Olivieri; Robert Yamashita; Elliott Vichinsky

Advances in the management of thalassemia have resulted in increased life expectancy and new challenges. We conducted the first survey of education and employment status of people with thalassemia in North America.

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Elliott Vichinsky

Children's Hospital Oakland

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Frans A. Kuypers

Children's Hospital Oakland Research Institute

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Sylvia T. Singer

Boston Children's Hospital

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John B. Porter

University College London

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Janet L. Kwiatkowski

Children's Hospital of Philadelphia

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Hae-Young Kim

University of North Carolina at Chapel Hill

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Sandra Larkin

Children's Hospital Oakland Research Institute

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