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Biomedical subjects

C E Johnson

Publications and source records attributed to C E Johnson.

240 records · Page 14Linked to original sources
PubMedDate not supplied

Effect of H1- and H2-receptor blockade on the inhibition of immediate cutaneous reactions.

The effects of cyproheptadine, cimetidine, and their combination on the wheal-and-flare skin-test response was evaluated using an intradermal skin-test technique in a double-blind, placebo-controlled study. Sixteen volunteers with known positive skin-test reactions to at least two antigens were divided into four treatment groups in a four-way crossover design. The patients received baseline intradermal skin tests on the back consisting of dilutions of mixed grasses and weeds, histamine diphosphate and codeine phosphate, and buffered-saline control. Following the baseline testing, the patients received cyproheptadine (4 mg q.i.d.), cimetidine (300 mg q.i.d.), the combination, and placebo in a double-blind trial. Of the 16 patients, 12 completed all treatment courses. Following pretreatment with cyproheptadine, cimetidine, and the combination, areas of wheal-and-flare response for each test substance were significantly suppressed. Although it appeared that the combination augmented wheal-and-flare suppression, the observed difference, compared with the cyproheptadine pretreatment sequence, was not statistically significant. The administration of H1 and H2 antagonists should be discontinued before the diagnostic use of immediate skin tests.

Adult↗
PubMedDate not supplied

Case report: progressive systemic sclerosis-like syndrome after bone marrow transplantation. Clinical, immunologic, and pathologic findings.

A young man developed chronic graft-versus-host disease (GvHD) after allogeneic bone marrow transplantation. The close resemblance of his skin changes to those of patients with progressive systemic sclerosis (PSS) prompted an examination for clinical and pathologic involvement of other organ systems. Many of the dermatologic, cardiac, renal and pulmonary findings in the transplant patient were similar to those seen in a comparison group of 38 patients with PSS.

Adolescent↗
PubMedDate not supplied

Estimation of creatinine clearance in children: comparison of six methods.

An evaluation and comparison of the accuracy of six published methods for estimating creatinine clearance from serum creatinine concentration in children are presented. The medical records of 59 patients were reviewed. The patients ranged from 1 to 18 years in age and had one or more 24-hour urine creatinine determinations completed. A total of 142 creatinine-clearance determinations were compared with the estimated creatinine clearances using each of six methods. All methods correlated well with calculated creatinine clearance. The average absolute and standard errors were greatest with the modified method of Counahan et al. and least with the method of Traub and Johnson. The error made by the method of Traub and Johnson was significantly smaller (p less than 0.05) than the error made by the methods of Schwartz et al., Counahan et al., and the modified method of Counahan et al. The method of Traub and Johnson also showed an equal tendency to overestimate and underestimate creatinine clearance. This method performed well regardless of the patients' weight, sex, or age; the method was not as accurate in children less than 107 cm in height. It is concluded that the method of Traub and Johnson for estimating creatinine clearance from serum creatinine concentration is the most accurate and nonbiased of the evaluation methods.

Adolescent↗
PubMedDate not supplied

Accuracy and reliability of dosing equations to individualize theophylline treatment of apnea of prematurity.

Apnea of prematurity is associated with high morbidity and mortality. Treatment generally includes supplemental oxygen and theophylline or caffeine. The half-life of theophylline is prolonged in newborns because of their immature cytochrome P-450 system, and there is considerable variation in the drug's metabolism in infants. We compared the accuracy, precision, and reliability of two equations that use postnatal age (PNA) to determine a maintenance dosage of theophylline with a standard maintenance dosage (SMD) that produced a steady-state serum theophylline concentration (STC) of 8 micrograms/ml for apnea of prematurity in 46 infants less than 34 weeks' gestational age (GA) and less than 36 weeks' postconceptional age (PCA). The two equations were mg/kg/day = [(0.2 x PNA in wks) + 5], and mg/kg/day = [(0.3 x PNA in wks) + 8]. Their reliability to predict the SMD was determined by correlation analysis. The precision and accuracy with which they predicted SMD were determined and analyzed by chi 2. The SMD did not correlate with the maintenance dosages calculated by equations 1 and 2 (r = 0.296 and 0.296, p > 0.05 in both cases). Multiple linear regression of SMD versus GA, PNA, and PCA was not significant (r = 0.33, p = 0.32). After stratifying data based on GA and performing correlation analysis of SMD versus PNA, a weak but significant correlation (r = 0.42, p = 0.517) was found for infants with GA between 31 and 34 weeks. Poor correlation was found between SMD versus PNA for infants 27-30 weeks' GA. Two new equations of the best fit line were generated using the same data.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMedDate not supplied

Prospective evaluation of two dosing equations for theophylline in premature infants.

STUDY OBJECTIVES: To evaluate prospectively the ability of two equations that we previously derived to predict maintenance theophylline dosages that provide a serum theophylline concentration (STC) of 8 micrograms/ml, the midtherapeutic range for treating apnea of prematurity; and to determine the number of further dosage adjustments and STC determinations required to achieve the target concentration in infants in whom it was not achieved initially. DESIGN: Prospective study. SETTING: A 37-bed neonatal intensive care unit. PATIENTS: Fifty-four infants 27-34 weeks' gestational age requiring intravenous hydrous aminophylline. INTERVENTIONS: Patients received a loading dose of 6 mg/kg intravenous aminophylline, followed by a maintenance dosage calculated using one of the two derived equations. The basis for equation selection was the gestational age of the patient. MEASUREMENTS AND MAIN RESULTS: Patients were stratified into two age groups: 27-30 weeks' gestational age (34 infants) and 31-34 weeks' gestational age (20 infants). The overall success rate for both equations in achieving the target concentration was 74%. When infants were stratified by gestational age, those dosed by Equation 1 had a 76% success rate and those dosed by Equation 2 had a 65% success rate. Overall, 14 of 54 infants received an average of 1.2 dosage adjustments. This represents more than a 50% reduction in the number of adjustments made before introduction of these equations. CONCLUSIONS: The ability of our previously derived equations to produce an STC within the midtherapeutic range for treating apnea of prematurity was demonstrated in the majority of patients studied (74%). Further, the number of subsequent dosage adjustments required to attain the target STC in infants who had failed to achieve this STC initially was significantly less than using older, more traditional regimens.

Apnea↗