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Biomedical subjects

W D Hager

Publications and source records attributed to W D Hager.

At least 73 records · Page 4Linked to original sources

Creatine kinase MB isoenzyme in the evaluation of myocardial infarction.

The measurement of serum CK-MB isoenzyme is a very sensitive and specific indication of myocardial injury since only myocardium has substantial amounts of CK-MB. Serum CK-MB levels are most helpful clinically when the total creatine kinase is nonspecifically elevated, as with intramuscular injections, cardiac catheterization, stroke, noncardiac surgery and electric cardioversion. Elevations of serum CK-MB occurring in Duchenne's muscular dystrophy and other neuromuscular disorders may be due to the presence of abnormal regenerative skeletal muscle fibers, which are known to contain large amounts of CK-MB isoenzyme. These examples emphasize that under normal, nonregenerative conditions, elevations of serum CK-MB are rare in the absence of myocardial injury.

Animals↗

Relationship between plasma concentration and dose of digoxin in patients with and without renal impairment.

The purpose of this study was to determine if there is a linear relationship between oral doses of digoxin and various measurements of steady-state digoxin plasma concentration and urinary excretion in patients with wide range of renal function. Ten patients (mean age 58 years) with creatinine clearances greater than 50 ml/min/1.73 m2 BSA (mean creatinine clearance 80 ml/min/1.73 m2 BSA) and nine patients mean age 61 years) with creatinine clearances less than 50 ml/min/1.73 m2 BSA (mean creatinine clearance 20 ml/min/1.73 m2 BSA) were given digoxin tablets orally at two or three different dose levels (dose range 0.0313--0.5 mg/day). After a dosing period equal to at least five half-lives, three to four consecutive daily digoxin plasma concentrations were determined. Plasma concentrations and urinary digoxin excretion were measured during one 24-hour dosing interval at each dose level. Digoxin plasma and urine concentrations were determined in triplicate using radioimmunoassay. Individual patient plots provided evidence of linearity for: digoxin 24-hour steady-state plasma concentration vs dose; digoxin 24-hour cumulative urinary excretion versus dose; and area under the digoxin plasma concentration-time curve during a 24-hour dosing interval vs dose. Absolute values for these various parameters indicated substantial interpatient variation probably due to patient differences in both digoxin absorption and digoxin total body clearance. These results indicate that there is a linear relationship between digoxin plasma concentration and dose in patients with normal and decreased renal function. This linearity is support for dose-independent pharmacokinetics of digoxin in man. We conclude from these data that a change in digoxin dose should result in a proportional change in digoxin plasma concentration over the dose range examined.

Administration, Oral↗

Endocarditis with myocardial abscesses and pericarditis in an adult: group B Streptococcus as a cause.

Group B beta-hemolytic Streptococcus, S agalactiae, is an uncommon cause of endocarditis in adults. We present the clinical, laboratory, and postmortem findings of an adult patient with group B streptococcal endocarditis and major arterial emboli. What to our knowledge are previously unreported features are purulent pericarditis and myocardial abscesses. Twenty-five cases of endocarditis caused by group B Streptococcus that are reported in the literature are reviewed.

Abscess↗

Amniotic fluid analysis in Rh-sensitized pregnancies.

This paper delineates the results of analysis of 234 Rh-sensitized pregnancies. It is now possible to predict the outcome in an Rh-isoimmunized pregnancy based only on the mean amniotic fluid, delta 450. This is an improvement over past methods since it does not depend upon calculation of weeks of pregnancy.

Amniotic Fluid↗

Evaluation of various methods of digoxin dosing.

The ability to precisely predict serum digoxin concentrations using 12 published methods in a group of 85 patients was undertaken. Two methods of estimating creatinine clearance and two estimates of ideal body weight were employed as input variables using the 12 dosing methods. This resulted in 40 relationships from which correlation coefficients and linear regression constants were derived for predicted versus measured serum digoxin concentrations. The correlation coefficients between predicted and measured serum digoxin ranged from -0.393 to 0.389. Possible explanations for the low correlation coefficients are interpatient variability in the kinetics of digoxin, the small number of subjects used to generate some of the digoxin dosing methods, undetected patient noncompliance in the present study, the use of empirically derived dosing methods, and/or the use of rather homogeneous patient populations to develop a given method while this study is comprised of a heterogeneous group of patients. The methods studied tend to overpredict serum digoxin concentrations and therefore generally allow safe, first approximations for digoxin dosing.

Adult↗