Total body potassium and serum potassium among eating disorder patients.

OBJECTIVE: The purpose of the study was to determine body composition, including total body potassium (TBK+), serum potassium, and lean body mass (LBM), in anorexia nervosa. METHOD: TBK+ measurements, serum potassium levels, and anthropometric measurements were obtained from four anorectic patients in the first week after their hospital admission. All four patients had normal serum potassium levels but three of the four had significant depletion of total body potassium. Two methods of calculating LBM, based on TBK+ measures or anthropometric assessment, produced different results. RESULTS: TBK+ may be depleted even when serum potassium levels are normal. It was also concluded that the two methods of calculating LBM were inaccurate. DISCUSSION: Patients may be at risk for cardiac arrhythmias and other physiological abnormalities even when serum potassium is normal since TBK+ may be low. The need for comprehensive assessment of body composition based on four compartment models is discussed.

Red blood cell volume (RBCV) and blood volume (BV) in male albino (NZW) rabbits with 99mTc.

Estimation of red blood cell volume (RBCV) and blood volume (BV) in experimental animals is important for studies concerning pharmaceutical distribution. In this study RBCV was measured, using 99mTc, in 64 male albino New Zealand rabbits with a body weight (BW) of 3.12 +/- 0.37 (SD) kg. The packed cell volume (PCV) was 38.17 +/- 2.37% (SD), the hematocrit (Hct) of the venous blood sample, corrected for trapped plasma, was PCV x 0.97 and the somatic hematocrit (Ho) was calculated as 0.89 x Hct. RBCV was measured using the pretinning method and the BV was calculated according to the formula BV = RBCV x 100/Ho. Labeling efficiency was 96.4% +/- 3.8% (SD). The RBCV was found to be 18.52 +/- 1.96 (SD) mL/kg (BW) and BV 56.12 +/- 4.82 (SD)mL/kg (BW). The correlation of the RBCV and BV to BW is given by the formulae: RBCV = 66.754 ln(BW(g)) - 478.702 (r2 = 0.624, P less than 0.001) and BV = -47.587 + 197.342 ln(BWkg) (r2 = 0.72, P less than 0.001). The 99mTc results do not differ significantly from those of the standard 51Cr procedure, but the 99mTc labeling method permits repetitive measurements at shorter intervals compared to 51Cr.

Evaluation of an immunoradiometric assay specific for the CK-MB isoenzyme for detection of acute myocardial infarction.

Clinical evaluation of patient's symptoms, electrocardiographic changes and increased serum enzyme levels, specifically creatine kinase (CK)-MB by electrophoresis, are established as the primary diagnostic indicators for myocardial infarction (MI). Two hundred fifteen patients were evaluated in this study. Of these patients, 102 were admitted to the coronary care unit and 113 were admitted to the emergency room and screened for possible MI. The immunoradiometric assay used in this study was a double antibody "sandwich" technique, which utilizes antibody to the M and B monomers of the CK isoenzymes. This assay is specific for the CK-MB isoenzyme, which is present in increased levels in MI. The intraassay coefficients of variation for 30 samples were 11.7% (mean 4.1 equivalent units [EU]/liter) and 8.4% (mean 15.4 EU/liter) and the interassay coefficients of variation for 30 samples were 11.1% (mean 2.6 EU/liter) and 8.1% (mean 13.6 EU/liter). The diagnostic sensitivity, specificity and accuracy in this study was 100%, respectively. The CK-MB by the immunoradiometric assay was found to be significantly more accurate than electrophoresis and, therefore, a reliable and also technically simpler replacement for electrophoresis.

Qualitative detection of a human placental lactogen--binding substance by radioassay.

Serum levels of human placental lactogen (hPL) were measured by radioimmunoassay, and a method was developed for the detection of an hPL-binding substance by radioassay. Three groups of women were investigated: (1) normal adult women who had never been pregnant; (2) women with normal pregnancies; (3) high-risk pregnant women (those demonstrating low levels of hPL). All women who had never been pregnant and most women who had normal hPL levels were found to be negative for the hPL-binding substance, whereas 80% of the women with hPL levels less than 4.0 nanograms per mililiter in the third trimester were positive for the hPL-binding substance. The presence of an hPL-binding substance might have a significant effect on pregnancy, since it could bind and reduce the functional availablity of hPL or disrupt normal production of it, thus causing fetal loss or premature delivery.