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Biomedical subjects

J L Ransom

Publications and source records attributed to J L Ransom.

32 records · Page 2Linked to original sources
PubMed1990

Indomethacin for patent ductus arteriosus closure. Application of serum concentrations and pharmacodynamics to improve response.

Indomethacin dosing for patent ductus arteriosus closure has been standardized despite wide interpatient variability in indomethacin pharmacokinetics. We compared a novel indomethacin dosing approach using individual pharmacokinetic and pharmacodynamic information (group A) with a control group from our institution (group B) and a level 3 university-based intensive care nursery (group C) who were dosed using current dosing guidelines. Permanent patent ductus arteriosus closure was achieved in 27 of 28 (96.4%) group A patients, 10 of 16 (62.5%) group B patients, and 7 of 13 (52.8%) group C patients. Success rates were significantly higher in group A than Groups B and C (P less than .02). Renal toxicity was the only toxicity reported in any group. The major manifestations of renal toxicity, ie, urine output below 1 mL/kg/h or increased serum creatinine by greater than or equal to 0.5 mg/dL, occurred in none of the group A patients but in seven (43.8%) group B and eight (61.5%) group C patients. Renal toxicity was significantly greater in groups B and C than group A (P less than .02). A pharmacodynamic concentration versus response curve was developed and proved predictive of patent ductus arteriosus closure rates in previous studies where indomethacin concentration versus response data were available. Serum concentration monitoring is a valuable adjunct to indomethacin therapy for patent ductus arteriosus closure, especially when a pharmacodynamic approach is used.

Algorithms↗
PubMed1989

Rapid sequential phenobarbital treatment of neonatal seizures.

The optimal serum concentration of phenobarbital in newborns and its safety at high doses are not well established. The dose response relationship of rapid sequential phenobarbital loading in the newborn was examined and the efficacy of high-dose monotherapy was compared with the addition of a second anticonvulsant for persistent seizure activity. A single loading dose of phenobarbital 15 to 20 mg/kg was initially administered to 120 newborns. Nonresponders received sequential bolus doses of 5 to 10 mg/kg until seizures ceased or a serum concentration of 40 micrograms/mL was obtained. Infants with refractory seizures received additional phenobarbital to a maximum serum concentration of 100 micrograms/mL. The seizures of 48 babies (40%) were controlled after initial loading and 37 of the remaining 72 subjects (51%) responded at serum concentrations of as great as 40 micrograms/mL. The seizures of only seven subjects were controlled at greater concentrations. A second anticonvulsant controlled seizures in 13 of the 28 subjects (46%) whose seizures were refractory to phenobarbital. A gestational age of less than 32 weeks was associated with a significantly better response to phenobarbital. Serum phenobarbital concentrations greater than 50 micrograms/mL produced only occasional feeding difficulty and sedation. It was concluded that sequentially administered IV phenobarbital controls seizures in both term and preterm newborns (77%). This therapeutic effect is dose dependent but plateaus at a serum concentration of 40 micrograms/mL. At greater serum concentrations, unresponsive patients should receive a second antiepileptic agent.

Dose-Response Relationship, Drug↗
PubMed1988

The effect of total parenteral nutrition-induced cholestasis on theophylline clearance in neonates.

The effect of total parenteral nutrition (TPN) induced cholestasis on theophylline clearance was examined in premature neonates. Thirty-six neonates receiving TPN and theophylline concurrently were reviewed. Aminophylline was administered according to a standard protocol of 6 mg/kg loading dose, followed by a maintenance dose of 2.5-5 mg/kg every 12 h. Of the 36 neonates reviewed, 18 developed cholestasis (direct bilirubin greater than or equal to 1 mg/100 ml and direct bilirubin greater than or equal to 60% of total bilirubin). The remaining 18 did not develop cholestasis. The two groups were closely matched for gestational age, 5-min apgar score, and sex. The neonates with cholestasis had a mean maximum direct bilirubin of 5.19 mg/100 ml (range 1-13.8 mg/100 ml) as compared to the patients without cholestasis who had a mean maximum direct bilirubin of 0.54 mg/100 ml (range 0.3-0.8 mg/100 ml). Steady-state theophylline clearance was determined at least once a week for at least 4 separate weeks. The study lasted a minimum of 8 weeks, and if more than one theophylline clearance was determined in any given week, the mean of these clearances was used. Both groups demonstrated a significant increase in mean theophylline clearance over time (from 16.09 and 18.60 ml/h/kg to 28.65 and 24.73 ml/h/kg for the cholestatic and noncholestatic groups, respectively). The mean slope, an indicator of the average rate of change of theophylline clearance, was 1.4 for the noncholestatic group and 2.5 for the cholestatic group, indicating that the theophylline clearance for neonates with cholestasis was not significantly different from that for neonates with normal liver function (p = 0.61) over time.

Bilirubin↗
PubMed1981

Treatment of childhood rhabdomyosarcoma at St. Jude Children's Research Hospital, 1962--78.

Between March 1962 and December 1978, 153 children with rhabdomyosarcoma (RMS) received treatment at St. Jude Children's Research Hospital. As of January 1979, 62 of these patients were still alive. Between 1962 and 1968, 20 patients were not treated by protocol, and, between 1968 and 1979, another 13 have been registered as "nonprotocol"; 6 of these 33 patients survive. Since 1968, 120 patients received treatment by 3 stage-related, multiple-modality programs. In the first protocol, chemotherapy consisted of vincristine, cyclophosphamide, and dactinomycin; 14 of 34 patients have survived after 6 to more than 10 years. In the second treatment program, which used adriamycin in addition to the 3 drugs cited above, 20 of 56 subjects remain free of disease after more than 2 to 5.5 years; toxicity of the multiple agents given in combination with radiotherapy proved intolerable and led to a modified 4-agent protocol for patients admitted since early 1977. Of 30 in this latter group, 22 are alive. Forty of 44 patients who remained free of RMS for more than 2 years continue to survive.

Adolescent↗
PubMed1980

Retroperitoneal rhabdomyosarcoma in children. Results of multimodality therapy.

The clinical course of 18 consecutive children treated for primary retroperitoneal rhabdomyosarcoma was reviewed. At diagnosis, 8 patients had regional unresected tumor and 10 patients had disseminated tumor, including 3 patients with documented bone marrow infiltration by tumor. Following combined modality therapy, 14 of 18 patients achieved a greater than 50% tumor response (11 complete and 3 partial responses); 4 patients failed to respond and died of progressive disease within eight months of diagnosis. Among the 14 patients responding, 7 patients had subsequent reextension of active tumor three to 16 months (median, 9 months) following the onset of therapy. Three of the 7 remaining patients died of treatment complications, 2 of intestinal obstruction and 1 of disseminated histoplasmosis, within the first year of therapy and at post-mortem examination had no demonstrable tumor. Four patients are alive and free of active tumor for 10+, 10+, 32+ and 33+ months from diagnosis. Treatment complications have included hematopoietic depression, mucositis, enteritis, intestinal obstruction, excessive weight loss, malnutrition, and life-threatening infection. These results illustrate limitations in current combined modality therapy of retroperitoneal rhabdomyosarcoma and the necessity for future treatment modifications to both reduce morbidity and to improve survival.

Adolescent↗
PubMed1980

High-dose methotrexate used alone and in combination for measurable primary or metastatic osteosarcoma.

High-dose methotrexate with leucovorin rescue was used alone or in combination with Adriamycin and cyclophosphamide for the treatment of 27 osteosarcoma patients with measurable indicators of disease. Three patients developed complete responses of measurable lesions, two had partial responses, two had static disease, one had symptomatic improvement, and one had return to normal of physical findings following treatment of a flat bone primary osteosarcoma. While the doses and frequency of administration of high-dose methotrexate differed from those used by previous investigators, these results suggest that aggressive treatment with high-dose methotrexate must be attempted to further evaluate its efficacy as single-agent therapy for osteosarcoma patients not eligible for adjuvant chemotherapy trials.

Antineoplastic Agents↗
PubMed1977

Histiocytosis X: abnormal cerebrospinal fluid cytology in extrahypothalamic central nervous system involvement.

The clinical course and long-term survival of a patient with acute disseminated histiocytosis X and extrahypothalamic CNS involement were presented. The clinical significance of histiocytes appearing in the CSF cocomitant with the onset of this neurologic syndrome was discussed. Detailed cytologic examination of the CSF in patients with histiocytosis X and CNS involvement was recommended.

Cerebellar Ataxia↗
PubMed1975

Hyperpipecolic acidemia associated with hepatomegaly, mental retardation, optic nerve dysplasia and progressive neurological disease.

A male infant with hyperpipecolic acidemia is described. To our knowledge this is only the second report of this disorder. As with the previous case, our patient's course was characterized by persistent hepatomegaly, severe mental retardation, progressive loss of developmental milestones and diminished visual acuity associated with nystagmus, abnormal discs and retinal changes. Death occurred at 2 years of age, following a progressive loss of neurological function. Pipecolic acid was repeatedly present in the serum at a concentrattion of 4-5 mg %. Trace amounts of this compound were also detected in the urine. In addition, an adaption of the method of Piez et al. (1956) for the direct quantitation of pipecolic acid in serum was evaluated and found to be very useful for the biochemical diagnosis of this disorder.

Amino Acid Metabolism, Inborn Errors↗
PubMedDate not supplied

Neonatal thrombosis: treatment with heparin and thrombolytics.

Thrombotic events are a serious and potentially fatal complication during the neonatal period. Despite clinically serious thromboses in up to one percent of neonates and less severe complications (e.g., catheter malfunction secondary to clots) in a much higher percentage, well-designed studies on prevention and treatment of thromboses are lacking. Treatment approaches are largely anecdotal and involve the use of heparin and, occasionally, thrombolytics. Proper monitoring of anticoagulant and thrombolytic effects is difficult because of the limited blood volumes available from neonates and the relatively large sample volumes needed for most coagulation studies. Activated clotting times (ACTs) are preferred because they use low blood volume and are a rapid bedside test. Heparin should be administered with an initial loading dose of 50-100 units/kg followed by a continuous infusion of 20 units/kg/h. Further doses should then be adjusted based on the ACT, targeting a value of 1.5-2.5 times the control. Thrombolytics also have been used in several case reports and are guided by both clinical response and serial D-dimer values. We prefer urokinase 100 units/kg/h for local infusion to the thrombus and urokinase 1000-10,000 units/kg/h for systemic therapy.

Fibrinolytic Agents↗
PubMedDate not supplied

Pharmacokinetic evaluation of cisplatin in children with malignant solid tumors: a phase II study.

In a phase II trial, cisplatin was given by two randomly assigned dose schedules to 53 children with malignant solid tumors. Both schedules, 30 mg/m2/week and 90 mg/m2 every 3 weeks, were associated with drug-related toxic effects involving the renal, hematopoietic, and neuromuscular systems. Pharmacokinetic studies indicated that the initial serum half-life of total platinum was 27.6 minutes, with a terminal half-life of 44.4 hours. Significant antitumor effect was noted in patients with neuroblastoma and malignant germ cell tumors. Use of cisplatin in combination therapy for patients with these diseases is indicated.

Adolescent↗