ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryA gas chromatographic on-column methylation technique was developed for the routine laboratory determination of 5-(p-hydroxyphenyl)-5-phenylhydantoin (p-HPPH), the principal urinary product of phenytoin (PHT) metabolism in man. 5-(p-Hydroxyphenyl)-5-(p-tolyl)hydantoin (HMPPH), a new internal standard, was synthesized and evaluated against 5-phenyl-5-(p-tolyl)hydantoin (MPPH), the compound normally used as the internal standard inp-HPPH assays. HMPPH withstood the challenges of intralaboratory quality control checks and tests of precision ofp-HPPH values at times when MPPH provided erratic and unreliable values. Both an enzyme and acid treatment of urine were studied for the purpose of hydrolysis ofp-HPPH-glucuronide, the form in whichp-HPPH is excreted in urine. The use of both treatments in studies of three different patient urines pointed to the conclusion that acid-catalyzed decomposition of PHT dihydrodiol, a minor urinary metabolite of PHT in man, was unimportant from the analytical point of view, contributing little if anything to total urinaryp-HPPH content. Some aspects of PHT disposition, as evidenced by studies of PHT plasma levels andp-HPPH urinary outputs in individual patients, are discussed.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryPlasma levels of haloperidol were monitored in children and teenagers suffering from psychotic episodes and/or abnormal movements (tics and Gilles de la Tourette's syndrome). Steady-state concentrations of haloperidol ranged from 0.7 to 19 ng/ml without any apparent relationship with the administered dose (15–285 μg/kg/day) and a 15-fold variability was observed for the same daily dosage. On the contrary, a significant (p< 0.02) relationship was found between the age of the patients and the plasma concentrations to dose ratios, lower values being present in younger patients. Side effects too appeared to be related to plasma levels, with a significant increase (p< 0.01) in incidence for concentrations over 6 ng/ml. In most of the cases suffering from tics and Gilles de la Tourette's syndrome, a positive response was associated with plasma levels of 1–4 ng/ml, while no relationship could be established for the psychotic group. The relevance of monitoring plasma drug levels when prescribing haloperidol in pediatrics is discussed.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryProcainamide and its major metabolite,N-acetylprocainamide, were measured by the homogeneous enzyme immunoassay technique (EMIT®). The reagents for the EMIT assays were supplied as a separate matched set for each assay. There is no crossreactivity by procainamide in the assay forN-acetylprocainamide or byN-acetylprocainamide in the assay for procainamide. Within-day precision determined by replicate analysis of samples in the therapeutic range gave a coefficient of variation of less than 5% for each assay. The day-to-day coefficient of variation was less than 6% for each assay. Quantitative results obtained by the enzyme immunoassay on serum samples from patients receiving procainamide were compared with the results obtained by a high pressure liquid chromatography procedure. For the procainamide assay the correlation coefficient (r) was 0.983; for theN-acetylprocainamide assay the correlation coefficient was 0.981. There were no false positives or false negatives. The immunoassay requires 50 μl of serum and the enzyme activity is measured in a spectrophotometer. An individual determination requires only 1 min to perform; therefore, the procedure can be used for either emergency or routine analysis.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryA brief summary of the diagnostic laboratory criteria for primary hypothyroidism and the practical aspects of the pharmacology of thyroid hormone therapy are presented. A minimal testing protocol for the adequacy of replacement therapy is advocated based on classic studies of restored thyroid function.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryHigh performance liquid chromatographic (HPLC) and enzyme immunoassay (EMIT®) methods for quantitating theophylline concentrations in serum were evaluated. For both methods, standard curves were linear over the therapeutic range of serum concentrations. Precision was acceptable, with coefficients of variation being less than 9%. The HPLC assay was slightly, but not significantly, more precise. No interference was noted in either method by caffeine, theobromine, diphylline, 8-chlorotheophylline, or by metabolites such as 1-methylxanthine, and 3-methylxanthine, or by potentially interfering compounds such as urea and uric acid. The two methods correlated well, with a correlation coefficient of 0.98%. The enzyme immunoassay was superior in terms of lower costs, greater ease of performance, and potential for automation.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryA liquid chromatographic procedure is described for rapid and accurate quantitation of vancomycin in serum. Vancomycin is extracted from serum by using a CM-Sephadex® column and is measured by reversed-phase chromatography with detection by UV absorption. Ristocetin is used as an internal standard. Concentration and instrument response are linearly related in the range of therapeutically useful concentrations. Results correlate well with those obtained by bioassay. The between-day coefficient of variation (n= 8) was less than 4%. Recovery of vancomycin from serum is nearly complete, and no substances that interfere with the procedure have been detected in clinical specimens.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryPeak expiratory flow, forced vital capacity, forced expiratory volume at 1 sec, and midmaximal expiratory flow were measured immediately before and 1 hr after a scheduled intravenous maintenance dose of aminophylline in 12 recently hospitalized asthmatic patients. Serum theophylline concentrations were also determined. No significant improvement was noted in any of these pulmonary function tests despite a significant increase in serum theophylline concentration (10.5 ± 5.2 to 18.2 ± 6.3 μg/ml,p< 0.001). These results were consistent with previously developed pharmacologic response theory.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID

摘要:

SummaryThe electroencephalographic (EEG) and behavioral effects of oral doses of phenytoin from 100 mg to 1 g in normal male volunteers were measured. The electroencephalogram exhibited decreases in power in the slow frequencies and increases in the fast frequencies, accompanied by an increase in mean frequency. These changes are similar to those seen with psychostimulants. They occurred at average plasma levels of 8 μg/ml and above. The time course and the intensity of EEG effects parallel plasma levels. Drug-related EEG changes were bilaterally symmetric. EEG changes at plasma levels of 8–12 μg/ml were not associated with behavioral toxic signs. These findings suggest that future psychiatric studies of phenytoin as a psychostimulant should include monitoring for plasma levels, with a minimum of 8 μg/ml as a guide to clinical efficacy.

ISSN:0163-4356    

出版商:OVID    

年代:1979

数据来源: OVID