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Biomedical subjects

A M Bolinger

Publications and source records attributed to A M Bolinger.

9 recordsLinked to original sources

Target dose adjustment of busulfan in pediatric patients undergoing bone marrow transplantation.

Published data suggest that the average concentration of busulfan at steady state (Bu Css) is critical for successful engraftment in children receiving busulfan as a conditioning agent for bone marrow transplantation (BMT). We previously found in children that a Bu Css <600 ng/ml correlated with autologous recovery/mixed chimerism; there was no correlation between Bu Css and regimen-related toxicity (RRT). In a cohort continuous with the previous trial, we prospectively evaluated targeted busulfan concentrations in 32 pediatric patients (age 0.6-18.5 years) with AML (n = 6), CML (n = 6) and non-malignant disorders (n = 20) receiving HLA-closely matched donor grafts. In this trial, individual busulfan pharmacokinetics were performed prior to admission. Busulfan doses were then adjusted to achieve a Bu Css target range of 600-900 ng/ml +/- 10% depending on donor source and disease. A repeat study was done following dose 1 of the conditioning regimen. Thirty of thirty-two (94%) patients achieved target concentrations. Total busulfan doses ranged from 10.9 to 29 mg/kg. Thirty of thirty-two patients (94%) have durably engrafted. Grade 3/4 RRT occurred in seven patients (21%). Targeting Bu Css ranges of 600-900 ng/ml significantly improved our rate of successful engraftment from 74% to 94% (P = 0.043). These results indicate that targeted busulfan dosing optimizes allogeneic engraftment in children.

Administration, Oral↗

An evaluation of engraftment, toxicity and busulfan concentration in children receiving bone marrow transplantation for leukemia or genetic disease.

Autologous recovery is a major problem with busulfan as a marrow ablative agent in conditioning children for allogeneic BMT. Data suggest the average concentration of busulfan at steady state (Bu Css) is critical for successful engraftment. We prospectively evaluated busulfan pharmacokinetics in 31 children (age 0.6-18 years) with AML (n = 9), and non-malignant diseases (n = 22) receiving HLA-closely matched (sibling, parent, unrelated) donor grafts. Blood samples were obtained following dose 1 and 13 of a standard 16 dose, 4-day regimen. The busulfan dose varied from 14 to 20 mg/kg. Patients received cyclophosphamide 200-240 mg/kg; 22/31 received 80-90 mg/kg of ATG. Eight patients failed to engraft (26%). ATG did not appear to influence engraftment (P = 0.38). Bu Css levels <600 ng/ml correlated with autologous recovery/mixed chimerism (P = 0.018). There were no graft failures in patients with a Bu Css >600 ng/ml. A correlation between Bu Css levels and regimen-related toxicity (RRT) was not identified for grade 2 or higher toxicities, only 1/31 had a Bu Css >900 ng/ml. Our data support the use of pharmacokinetic monitoring of busulfan.

Adolescent↗

Use of ATP-MgCl2 in the evaluation and treatment of children with pulmonary hypertension secondary to congenital heart defects.

BACKGROUND: Pulmonary hypertension results in increased morbidity and mortality in children after surgical repair of congenital heart defects. Various vasodilators have been unsuccessful in providing preferential pulmonary vasodilation in these patients. Identification of a more preferential pulmonary vasodilator would improve the assessment, management, and outcome of these children. To determine whether ATP-MgCl2 is a preferential pulmonary vasodilator in children with pulmonary hypertension secondary to congenital heart defects, ATP-MgCl2 was administered during routine cardiac catheterization, and the effects were compared with tolazoline. In addition, ATP-MgCl2 was infused intravenously during episodes of postoperative pulmonary hypertension. METHODS AND RESULTS: During cardiac catheterization in 28 children, the effect of ATP-MgCl2 on the pulmonary artery pressure (PAP) and pulmonary vascular resistance index (Rp) was compared with tolazoline. ATP-MgCl2 (0.1 mg of ATP per kilogram per minute) decreased mean PAP by 24% (P < .05) and Rp by 47% (P < .05) without changing mean systemic arterial pressure or systemic vascular resistance. These effects were comparable to those of tolazoline (1 mg/kg). ATP-MgCl2 produced no significant side effects; tolazoline caused tachycardia, nausea, and vomiting. After cardiac surgery in 7 patients, ATP-MgCl2 decreased PAP by 14% (P < .05) and systemic arterial pressure by 6% (P < .05) and eliminated pulmonary hypertensive crises in 3 of 3 patients. CONCLUSIONS: ATP-MgCl2 is a safe, effective, and preferential pulmonary vasodilator in children with pulmonary hypertension secondary to congenital heart defects. It is useful for evaluating pulmonary vasoreactivity during cardiac catheterization and for treating pulmonary hypertension after cardiac surgery.

Adenosine Triphosphate↗

Recombinant interferon gamma for treatment of chronic granulomatous disease and other disorders.

The chemistry, biological activity, and pharmacokinetics of gamma-interferon and recombinant interferon gamma are reviewed, and the agent's clinical efficacy, adverse effects, and dosage and administration for the treatment of chronic granulomatous disease (CGD) and other disorders are described. Endogenous gamma-interferon is a 166-amino-acid protein encoded by a single gene on chromosome 12. Recombinant human interferon gamma is purified from Escherichia coli as a monomer containing 139 amino acids. Gamma-interferon has antiviral, immunomodulatory, and antiproliferative activity. Serum concentrations of recombinant interferon gamma increase in proportion to the dose. Clearance after i.m. or s.c. administration fits a two-compartment model. The half-life is 3.5-7.5 hours, and bioavailability is 89%. Evidence that recombinant interferon gamma can enhance phagocytic oxidative metabolism led to its evaluation for use in the treatment of CGD. Clinical studies showed that the agent decreases the frequency of serious infections in patients with CGD. Recombinant interferon gamma has shown only limited success in the treatment of metastatic renal cell carcinoma (RCC), both as a single agent and in combination with recombinant interferon alfa. Similarly, although interferons appear to be able to change cytogenetic abnormalities in some patients with Philadelphia chromosome-positive chronic myelogenous leukemia, therapy with recombinant interferon gamma has led to minimal success. However, the agent has produced some encouraging results in atopic dermatitis. The adverse effects of recombinant interferon gamma in patients with CGD usually consist only of fever, chills, headache, and erythema. The recommended dosage in CGD-afflicted children whose body surface area is greater than 0.5 sq m is 50 micrograms/sq m given by s.c. injection three times a week for life. Recombinant interferon gamma has given new hope to patients with CGD. Although the drug is very expensive, the cost may be offset by fewer hospitalizations to treat infection.

Carcinoma, Renal Cell↗

Intravenous gamma-globulin: clinical applications in pediatric care.

Intravenous gamma-globulin is being used with increasing frequency in the care of children. This article reviews the physiology of the immune system, the pharmacology of intravenous gamma-globulin, and presents four case studies. Administration guidelines, adverse reactions, and appropriate interventions are discussed. A table comparing four commonly used products is presented.

Adolescent↗

Influence of food on the absorption of albuterol Repetabs.

A study was conducted in 12 healthy, nonsmoking male volunteers to examine the effect of food intake on the absorption profile of albuterol repeat-action tablets. This randomized crossover study consisted of two phases separated by a 1-week washout period. All subjects fasted 10 hours preceding drug administration. Each subject received two 4 mg albuterol repeat-action tablets with and without a high fat content breakfast. Plasma albuterol concentrations were determined by a gas chromatographic/mass spectrophotometric assay. Relative bioavailability was assessed by comparing areas under the plasma-albuterol concentration time curves as well as peak concentrations and time to peak concentration. No significant differences were noted between the two treatment phases in the area under the curve or peak plasma concentrations. The areas under the curve were 100 and 105 hr.ng/ml when the drug was administered with and without food, respectively. The corresponding peak plasma concentration values were 9.4 and 10.4 ng/ml, respectively. The only significant difference observed was in the maximum time to reach peak plasma concentrations, which was delayed by about 1 hour when the drug was administered with food. Therefore, food has minimal effect on the absorption of albuterol from repeat-action tablets.

Adult↗

Treatment of nontuberculous mycobacterial infections in pediatric patients.

Two cases of Mycobacterium avium-intracellulare complex (MAC) infections are described, and the diagnosis, clinical features, and management of MAC infections are reviewed. In case 1, a four-year-old boy was diagnosed as having both acquired immunodeficiency syndrome (AIDS) and disseminated MAC infection. He was treated with a combination of isoniazid, ethambutol hydrochloride, rifabutin, and clofazimine. Results of susceptibility testing showed that the MAC was susceptible to rifabutin and ethambutol with intermediate susceptibility to isoniazid. The child developed severe adverse effects that necessitated the discontinuation of rifabutin therapy. Despite therapy, blood cultures remained positive for MAC. The child died of disseminated human immunodeficiency virus and MAC infection. In case 2, a 20-month-old girl was found to have a prevertebral retropharyngeal mass caused by MAC. The child did not have evidence of immunologic deficiency. She was treated with streptomycin, ethambutol, clofazimine, and rifabutin. Streptomycin was discontinued after three months. After seven months the mass decreased in size, allowing for surgical resection. Intraoperative cultures were negative for mycobacteria. Ethambutol, rifabutin, and clofazimine were continued for a total of 12 months, at which time the child was determined to be clinically and radiologically cured. Empiric multidrug antituberculous therapy should be initiated in patients with suspected disseminated nontuberculous mycobacterial infection because final isolation, identification, and susceptibility testing may take several weeks. Clofazimine and rifabutin, in combination with isoniazid and ethambutol, may be useful in the treatment of some MAC infections. At least four drugs are given, and regimens often consist of six drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Acquired Immunodeficiency Syndrome↗