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.

Prostate cancer imaging with a new monoclonal antibody: a preliminary report.

BACKGROUND: Optimal treatment of prostate cancer depends on accurate staging. Computed tomography (CT) and magnetic resonance imaging have severe limitations, and standard bone scanning can show only destructive osseous metastases. A radiolabeled antibody specific to prostatic adenocarcinoma could theoretically find evidence of soft-tissue metastases and lymph node involvement. METHODS: An immunoconjugate (CYT-356) consisting of a murine monoclonal antibody against human prostatic adenocarcinoma bound to a linker-chelator and radiolabeled with indium 111 was administered intravenously to seven patients with documented Stage D adenocarcinoma of the prostate. Planar imaging was done on days 1, 2, and 3 after injection. The CYT-356 scans were compared with standard technetium Tc99m sulfur colloid bone scans and CT scans. RESULTS: Optimal imaging results were obtained on the 72-h scans. All patients had lesions on both the 99mTc-sulfur colloid bone scan and the CYT-356 scan. The location of the lesions correlated to a great extent. Two patients had positive lesions biopsied, and both biopsies showed the presence of metastatic prostatic carcinoma. There were no side effects from administration of the antibody. CONCLUSION: In this preliminary study, CYT-356 scanning appears to be a promising agent to accomplish specific staging of prostatic carcinoma.

Immunoscintigraphy of prostatic cancer: preliminary results with 111In-labeled monoclonal antibody 7E11-C5.3 (CYT-356).

A phase 1 study was conducted with the investigational immunoscintigraphic agent, 111In-CYT-356, a radiolabeled, site-specific immunoconjugate of monoclonal antibody 7E11-C5.3, in 40 patients with prostatic carcinoma and known distant metastases. Each patient received a single intravenous infusion of CYT-356 (dose range, 0.1-5 mg) radiolabeled with approximately 5 mCi of 111In. None of the patients experienced adverse reactions. One patient who received a 5-mg dose developed antibodies to the CYT-356 immunoconjugate. 111In-CYT-356 immunoscintigraphy detected bony metastases in 21 of 38 patients (55%), including 12 of 14 (86%) receiving concomitant hormonal therapy, and soft tissue lesions in four of six patients (67%). Antibody imaging detected occult lesions in the bony pelvis and lumbar spine, which were confirmed by follow-up imaging tests, in one patient. Higher CYT-356 doses may clear the blood pool more slowly. These results suggest that 111In-CYT-356 can be safely administered to patients with prostatic carcinoma and that further clinical investigation of this agent is warranted.

Experimental increase in brain HIPDM uptake by hypercapnia.

The 30-min brain uptake of [125I]HIPDM was measured in conscious rats--normocapnic (n = 8), hypercapnic (n = 12), and hyperoxic (n = 6). A mean 41.2% higher uptake was found in the brains of hypercapnic animals (p less than 0.01). In the three groups of rats, brain HIPDM uptake had a negative correlation with body weight (p less than 0.001) and a positive correlation with arterial pCO2 (p less than 0.01), when adjusted for body weight. These results indicate that HIPDM uptake with hypercapnia may be used as a provocative test to measure cerebral blood flow reserves.

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.

Subacute and chronic bone infections: diagnosis using In-111, Ga-67 and Tc-99m MDP bone scintigraphy, and radiography.

The usefulness of indium-111 white blood cell scintigraphy in the diagnosis of subacute or chronic bone infection was examined in 21 orthopedic patients. In-111 WBC imaging was compared with gallium-67 and technetium-99m methylene diphosphonate skeletal scintigraphy and bone radiography, all studies being performed within 1 week. In-111 WBC scintigraphy showed no definite advantage over Ga-67 scintigraphy in the identification of chronic bone infection. The two tests had the same sensitivity (80%) and similar specificity (In-111 WBC 75%, Ga-67 83%; difference not significant). Bone radiography had a sensitivity of 60% and a specificity of 67%. A negative Tc-99m MDP bone scintigram ruled out infection (sensitivity 100%), but because of low specificity (25%), final evaluation required performance of Ga-67 or In-111 WBC scintigraphy.

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.

Diagnosing myocardial infarction with a radioimmunoassay for the B-monomer of the creatine phosphokinase isoenzymes.

A diagnosis of myocardial infarction (MI) is usually established by the evaluation of clinical symptoms, electrocardiographic changes, and serum enzyme levels, specifically creatine phosphokinase, subunit MB (CK-MB), by electrophoresis. A total of 215 patients were evaluated in this study. One hundred two of them were admitted to the coronary care unit and 113 to the emergency room, where they were screened for possible MIs. The radioimmunoassay (RIA) used in this study determines levels of the CK-MB isoenzyme by detecting the B monomer, which also has 100% cross-reactivity with the CK-BB isoenzyme. The intra-assay coefficients of variability (CVs) for 30 samples were 22% (means = 7.0 ng/ml) and 11% (means = 47.3 ng/ml), and the interassay CVs for 30 samples were 17% (means = 7.1 ng/ml) and 9.2% (means = 49.3 ng/ml). Of the 215 patients evaluated, 21 had myocardial infarction by the criteria in the study. The diagnostic sensitivity, specificity, and accuracy were 100.0%, 92.8%, and 93.5% respectively. These values increased to 100.0%, 96.9%, and 97.2% when only coronary care unit patients were considered. The CK-MB RIA was found to be a reliable replacement for electrophoresis, but it was nonspecific in some patients.

Comparisons of scintigraphy with In-111 leukocytes and Ga-67 in the diagnosis of occult sepsis.

In a prospective study involving 32 patients with clinical suspicion of focal infection, the sensitivity and specificity of In-111-labeled leukocyte (In-WBC) scintigraphy were compared with those of Ga-67 scintigraphy performed 24-48 hr later. Of a total of 192 body sites studied, 26 foci of infection were diagnosed by aspiration, cultures, or chest radiographs. Indium-WBC indicated 19 (73%) true-positive (TP) and four (2.5%) false-positive (FP) foci of abnormal accretion; Ga-67 had 21 (81%) TP and 15 (9%) FP. The 7/26 (27%) false-negative (FN) In-WBC scintigrams involved infection foci of more than 2-wk duration; the 5/26 (19%) FN Ga-67 studies were in patients with infections manifested for less than 1 wk. The results of this study are useful in considering the indications of the two tracers.

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.

Circulating carcinoembryonic antigen in pancreatic carcinoma.

Circulating CEA levels were determined in 102 patients wtih histologically proven pancreatic carcinoma and 26 patients with chronic pancreatitis. In the group with pancreatic carcinoma eleven patients had resectable tumors, the mean CEA in the nonjaundiced patients was 10 +/- 5 ng/ml while the mean value in jaundiced patients in this group was 27 +/- 40. Thirty-four patients with nonmetastatic locally unresectable disease had a mean serum CEA of 25 +/- 52 with a range of 1 to 250 ng/ml. Twenty-one percent had values of 5 ng/ml or less. The mean value in 57 patients with metastatic disease was 97 +/- 194 with a range of 0.05 to 1000 ng/ml and 19 percent had values of 5 ng/ml or less. Survival of patients with locally unresectable or metastatic carcinoma was significantly longer in those patients who had a normal CEA at the time of diagnosis. Circulating CEA in the metastatic group was much lower in patients with nonhepatic metastases as well as in those with well differentiated adenocarcinoma histology. Twenty-three patients with chronic pancreatitis and normal serum bilirubin had a mean CEA value of 5.3 +/- 4 ng/ml with 65% of values being 5 ng/ml or less but the CEA ranged from 4.6 to 27 in three who were jaundiced.

Initial levels of CEA and their rate of change in pancreatic carcinoma following surgery chemotherapy and radiation therapy.

CEA levels and their rate of change in 41 patients with pancreatic carcinoma following surgery, chemotherapy and radiation therapy were determined. Surgical resection, though not curative, was associated with a decrease in CEA level, with approximately half these levels returned to normal. No correlation with survival was noted. CEA levels are increased by obstructive jaundice. Radiation alone or in combination with 5-Fluorouracil did not change CEA levels in patients with locally unresectable pancreatic carcinoma. CEA levels progressively increased in patients with widespread metastatic pancreatic carcinoma, who expired from their disease.