Racial differences in blood pressure control.

Children from an entire biracial geographical population were examined for blood pressure. A sample of 278 children, stratified by diastolic blood pressure, was reexamined 1 to 2 years later. Dopamine beta-hydroxylase, renin activity, and resting heart rate were observed in black and white children. In the group with high blood pressure, whites had higher heart rates and greater renin activity than blacks. Dopamine beta-hydroxylase concentrations in blacks were lower than in whites over the entire spectrum of blood pressure levels. High blood pressure seems to have a different metabolic background in the two races which may influence the early natural history of essential hypertension. Therefore, the rationale of prevention, and possibly treatment, of early hypertension in blacks and whites may differ.

Evaluation of an immunoextraction procedure for the estimation of free thyroxine concentration.

We have examined the performance of a commercial free-thyroxine assay in which a radiolabeled T4 derivative permits the competitive quantitation of extracted T4 in the presence of serum proteins. After the total T4 pool had been radiolabeled with either I-125 T4 or I-131 T4, the solid-phase antibody was found to be associated with 4-8% of the total T4 present in the assay tube. Of this, 15-60% was displaceable (antibody-bound). The assay estimated free T4 to be 0.6-1.8 ng/dl in euthyroid patients, and distinguished them from hyperthyroid (sensitivity 91%) and hypothyroid patients (sensitivity 91%) without apparent TBG dependence. In patients with severe nonthyroidal illnesses, the assay correctly quantitated a reduced extracted mass in some. In other patients, however, the assay results were inappropriately lower than the actual extracted mass, in agreement with the FTI but not with the measurements of free T4 by dialysis. This assay appears to produce clinically appropriate results in most patients. In some nonthyroidally ill patients however, the indicated free T4 is spuriously low.

Carcinoembryonic antigen: assay following heat compared with perchloric acid extraction in patients with colon cancer, non-neoplastic gastrointestinal diseases, or chronic renal failure.

Heat inactivation has been proposed as an alternative to perchloric acid (PCA) precipitation for the extraction of carcinoembryonic antigen (CEA) from human plasma. We examined a commercial RIA kit using heat inactivation, and compared results with those obtained with PCA precipitation. Adequate sensitivity (1.5 micrograms CEA/l plasma), satisfactory analytical recovery of CEA added to plasma, and dilutional linearity of samples found to have elevated CEA concentrations, were demonstrated for the heat-inactivation assay. Between-assay precision was better with the heat inactivation than with the PCA assay. Although the absolute concentration of CEA estimated after heat inactivation was consistently lower than that estimated after PCA extraction of plasma specimens, there was excellent correlation between results obtained with the two methods in colon cancer patients free of disease, colon cancer patients with residual or recurrent disease, patients with benign gastrointestinal disease, and in patients with chronic renal failure. We conclude that the heat-inactivation assay is an excellent alternative to the PCA assay.

Bone scan patterns of patients with diffuse metastatic carcinoma of the axial skeleton.

Bone scan findings (using 99mTc-stannous pyrophosphate) in five patients with diffuse metastatic carcinoma of the axial skeleton are reviewed. Although there were few visually recognizable asymmetries of tracer localization, the diffuse involvement was diagnosed through abnormally elevated counting rates in the axial skeleton, decreased visualization of the kidneys, and faint or absent visualization of the appendicular skeleton.

Assessment of serum myoglobin as a marker for acute myocardial infarction.

The reliability of serum myoglobin as a marker for acute myocardial infarction was evaluated in 157 consecutive coronary-care admissions. Admission myoglobin was elevated in 47 of 52 patients with acute infarction. Excluding those patients who presented later than 24 hr after symptom onset, only one patient with acute infarct had a normal admission myoglobin. In 22 of 105 patients with no infarct, myoglobin was elevated in association with angina, congestive heart failure, arrhythmias, and renal insufficiency. The detection of acute infarction by serum myoglobin measurement equals that of serial serum creatine phosphokinase isoenzymes (CPK-MB) by electrophoresis, but an elevated myoglobin is not specific for what is now considered clinically significant myocardial infarction.

Two radioimmunoassays compared with isoenzyme electrophoresis for the detection of serum creatine kinase-MB in acute myocardial infarction.

We have evaluated two commercial radioimmunoassay (RIA) reagent kits for the estimation of the MB isoenzyme of creating kinase (CK). Although both methods use CK-B antisera and radioiodinated CK-B, one ("M" for Mallinckrodt) uses hybridized CK-MB for calibration, while the other ("NMS" for Nuclear Medical Systems) uses CK-B. Both assays provide adequate sensitivity, precision, and specificity for the estimation of serum CK-MB. Ninety-nine patients admitted consecutively to our coronary care unit were studied. Apparent CK-MB was measured by both RIAs and results compared with CK-MB enzymatic activity after electrophoresis (E). CK-MB was elevated, as judged by E and by M, in all of 42 patients with acute myocardial infarction (AMI), and in 40 of the 42 by NMS. Of the 57 patients who did not have an AMI, eight had elevated CK-MB by E, 16 by M, and 25 by NMS. Patients with persistently elevated apparent CK-MB concentrations not associated with AMI were identified by M and by NMS, but not by E. The ability to differentiate AMI from no infarction in patients was best with E, and was not satisfactory by NMS. Although the detection of AMI by M equaled that by E, the large number of apparent false-positive results hindered the clinical application of RIA CK-MB measurements.

An assessment of methods for the estimation of free thyroxine.

Three commercial kit methods for the estimation of free thyroxine (FT4) (Clinical Assays, Corning Medical, Damon Diagnostics) were evaluated. The effects of changes in thyroxine-binding globulin (TBG) and FT4 concentrations in these systems were assessed. Measurements were made in serum samples from hyperthyroid, hypothyroid, and euthyroid patients with different TBG concentrations, and results were correlated with functional thyroid status. The Clinical Assays and Damon Diagnostics assays were found to be essentially independent of binding-protein concentration effects and responded appropriately to changes in FT4 concentration. The method of Corning Medical does not measure FT4 directly but yields an FT4 index calculated from a TBG-dependent T4 uptake and the total T4 concentration. This corning index yields falsely elevated results in patients with marked elevation in TBG concentration.

An evaluation of prepackaged columns for the separation of carcinoembryonic antigen from perchloric acid: concise communication.

Commerically available Sephadex buffer-exchange columns for the separation of carcinoembryonic antigen (CEA) from perchloric acid were evaluated. Elution patterns of individual columns were found to be variable, but separation of acid from CEA could be accomplished. Repeatability of replicate elutions and agreement with dialysis results were acceptable. Nevertheless, the method is excessively time-consuming and inefficient for processing large numbers of patient samples.

Unusual pattern of pulp canal obliteration following luxation injury.

Pulp canal obliteration can occur as a result of tooth injury. A case report is presented in which a 6-yr-old patient developed partial pulp canal obliteration of a maxillary central incisor 9 months after luxation injury. The mineralization created unusual canal morphology which presented some difficulty in endodontic treatment of the tooth.

Evaluation of mini-dose heparin administration as a prophylaxis against postoperative pulmonary embolism: a prospective double-blind study.

A prospective double-blind study was instituted in a group of 150 general surgical patients to test the effectiveness of mini-dose heparinization in the pre- and postoperative periods. There was a 21 per cent reduction in the incidence of deep venous thrombosis in the heparin treated group. A radiopharmaceutical imaging technique with 99m-technetium macroaggregated albumin was used to evaluate the deep venous system. The procedure proved to be simple, safe, and painless; however, it was difficult to differentiate venous stasis from deep venous thrombosis. A negative study was good evidence that deep venous thrombosis did not exist. An additional benefit of this procedure was that a perfusion lung study could be obtained which provided additional information regarding pulmonary embolism without injecting additional radiopharmaceutical. Again, the negative perfusion lung study provided more information.

A review of applications of MRI in soft tissue and bone tumors.

Due to excellent soft tissue contrast and multiplanar imaging capability, MRI is assuming a major role in recognition, staging, and treatment planning of soft tissue and bone tumors. Direct sagittal, coronal, and axial images permit assessment of intraosseous and extraosseous extension of tumors and their relationship to the joints and neurovascular structures, and detection of "skip" lesions. MRI allows improved detection of recurrent tumors in the presence of non-ferromagnetic metallic implants as compared to CT. In the evaluation of soft tissue tumors, MRI is more sensitive than CT and allows differentiation among fat, muscle, tendon, bone, and vascular structures based on signal characteristics. Over a period of 18 months, 100 soft tissue masses and bone tumors were evaluated using MRI. Spin echo sequences with T1 and T2 weighted images were most valuable in differentiating normal and abnormal tissues. Calculated comparative measurements of relaxation times showed no reliable difference between benign and malignant tumors.

MRI of soft tissue vascular malformations.

Magnetic resonance imaging (MRI) is constantly progressing as an important imaging modality for the evaluation of the cardiovascular system and vascular malformations. Due to its superior contrast resolution and sensitivity, MRI is able to differentiate between fat, muscle, bone, and vascular structures. It provides three-dimensional information without the use of ionizing radiation or invasive procedures. We evaluated 11 vascular malformations by MRI using Spin Echo T1 and T2 weighted images. MRI provided more information than computerized tomography, and, in many instances, obviated the need for angiography.

Impetigo. Bacteriologic features and renal involvement.

One hundred children with impetigo were studied with particular emphasis upon the organism causing the infection and associated renal complications. In 50 per cent of cases, Group A beta-hemolytic streptococcus grew on cultures of material from the lesions, and evidence of recent infection with this organism as shown by an elevation of antistreptolysin O titer was present in an additional 17 per cent of cases. Acute glomerulonephritis developed in three of the 66 children with bacteriologic or serologic evidence of streptococcal infection. Four other children in this group and nine children with staphylococcal impetigo had unexplained microscopic hematuria. All children with nephritis already had evidence of the disease when first seen. In most of those with unexplained hematuria, this condition was detected at the first visit. Hematuria developed in others while they were receiving systemic antibiotics. The significance of isolated microscopic hematuria is uncertain, but is seen often in association with cutaneous infection with both staphylococcus and streptococcus. Microscopic hematuria as defined is apparently not prevented by antibiotic therapy. If acute glomerulonephritis that follows streptococcal cutaneous infection is to be prevented, streptococcal impetigo will have to be treated promptly after onset.

Gold nephropathy in juvenile rheumatoid arthritis.

A 2-year-old girl was treated with gold salts for juvenile rheumatoid arthritis. Treatment had to be discontinued when persistent proteinuria was detected. As this case report indicates, close monitoring of the urine is mandatory during treatment with gold salts to detect early signs of toxicity: hematuria followed by casts and then proteinuria as therapy is continued. Histologic examination with electron microscopy will help to differentiate the different forms of gold toxicity. When the findings are consistent with gold-induced renal involvement, therapy should be discontinued. The gold nephropathy usually resolves in time, with no permanent renal damage.