Publications by authors named "Amanda Pfeiffer"

The mechanisms of action of l-glutamine for the treatment of sickle cell disease (SCD) are not well understood and there are no validated clinical biomarkers to assess response. We conducted a three-week, dose-ascending trial of glutamine and measured the pharmacokinetic (PK) exposure parameters, peak concentration (C) and area under the curve (AUC). We used a panel of biomarkers to investigate the pharmacodynamics (PD) of glutamine and studied PK-PD relationships.

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Background And Objective: L-Glutamine is a treatment for children and adults with sickle cell disease. A comprehensive evaluation of the pharmacokinetics of L-glutamine in sickle cell disease has not been conducted. We aimed to assess the effects of long-term dosing, multiple dose levels, and food intake on L-glutamine exposure in patients with sickle cell disease compared to normal participants.

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Children with sickle cell disease (SCD) who began hydroyxurea before age five years scored no differently on a measure of cognitive funciton than age, sex, and race-matched unaffected peers.

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Aerobic and resistance exercise during and after cancer treatment are important for health-related outcomes, however treatment-specific barriers may inhibit adherence. We explored the effect of lower-frequency exercise training on fitness, body composition, and metabolic markers (i.e.

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Background: Evidence for aspirin efficacy testing in pediatrics is limited, especially outside of cardiology, yet thrombotic events have high morbidity in other areas such as pediatric transplant surgery. Debates about whether thromboembolic events while on aspirin represent "aspirin resistance" or "high on-treatment platelet reactivity" persist, given the poor intertest agreement between testing platforms.

Procedure: This prospective observational study involved measuring aspirin efficacy using ex vivo testing of platelet aggregation (VerifyNow-Aspirin, VN) and urine 11-dehydrothromboxane B2 (AsprinWorks, UTxB2) contemporaneously at up to three time points after major noncardiac organ transplant surgery.

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Hydroxyurea (hydroxycarbamide) is an effective treatment for sickle cell anaemia (SCA), but clinical responses depend primarily upon the degree of fetal haemoglobin (HbF) induction and the heterogeneity of HbF expression across erythrocytes. The number and characteristics of HbF-containing cells (F-cells) are not assessed by traditional HbF measurements. Conventional hydroxyurea dosing (e.

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Neurologic complications are common in patients with sickle cell anemia (SCA), but conventional tools such as MRI and transcranial Doppler ultrasonography (TCD) do not fully assess cerebrovascular pathology. Cerebral tissue oximetry measures mixed oxygen saturation in the frontal lobes (S O ) and provides early prognostic information about tissue at risk of ischemic injury. Untreated patients with SCA have significantly lower S O than healthy controls that declines with age.

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Article Synopsis
  • Sickle cell disease (SCD) affects over 100,000 people in the USA and millions globally, with hydroxyurea being the main treatment to improve patient outcomes.
  • Due to individual differences in drug response, the traditional method of starting hydroxyurea at a standard dose often leads to inadequate treatment for many patients.
  • The Hydroxyurea Optimization through Precision Study (HOPS) is a multi-center trial aimed at comparing standard dosing to a personalized, pharmacokinetics (PK)-guided approach to determine which method works better for children with SCD.
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Background: Severe anemia is common and frequently fatal for hospitalized patients in limited-resource settings. Lack of access to low-cost, accurate, and rapid diagnosis of anemia impedes the delivery of life-saving care and appropriate use of the limited blood supply. The WHO Haemoglobin Colour Scale (HCS) is a simple low-cost test but frequently inaccurate.

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Background: Bioelectrical impedance analysis (BIA) is commonly used to assess fat-free mass (FFM) and fat mass (FM) in breast cancer patients. However, because of the prevalence of overweight, obesity and variable hydration status in these patients, assumptions for existing prediction equations developed in healthy adults may be violated, resulting in inaccurate body composition assessment.

Methods: We measured whole-body FFM using single-frequency BIA (50 kHz) and dual-energy x-ray absorptiometry (DXA) in 48 patients undergoing treatment for breast cancer.

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Background: Iron deficiency is a common and clinically diverse hematologic disorder in childhood for which oral iron is often an infeasible or ineffective treatment option. Intravenous (IV) iron can be an efficient and highly successful means of iron replacement but its use has not been well-characterized on a large scale in pediatrics.

Procedure: All IV iron doses administered to patients for iron replacement therapy at a tertiary pediatric hospital from January 2010 through October 2016 were evaluated.

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Objectives: This study was designed to compare long-term clinical outcomes of drug-eluting stents (DES) versus bare metal stents (BMS) in patients with saphenous vein graft (SVG) disease in the "real world."

Background: The safety and efficacy of DES versus BMS in SVG remains uncertain due to contradictory reports of either lower revascularization rates with DES; or clinical equivalence to BMS; or even an excess of clinical events associated with DES use.

Methods: We identified consecutive patients who underwent stent placement within a de novo SVG lesion between May 1, 2003 and July 31, 2007.

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