Confidence intervals and sample size calculations to compare variant frequencies.

Direct mutagenicity tests offer the opportunity of monitoring human populations to detect evidence of genetic damage that occurs in vivo. As such these tests offer the potential of linking earlier exposures to mutagenic agents to subsequent health effects. One such test detects mutant T-lymphocytes that arise in vivo in human peripheral blood.

Evidence for an increased risk for hypertension with centrally located body fat and the effect of race and sex on this risk.

Data from the First Health and Nutrition Examination Survey (HANES), 1971-1974, were used to examine the relationship between blood pressure and the distribution of subcutaneous body fat in 5506 survey participants, ages 30-59. Triceps and subscapular skinfolds were used as approximations of peripheral and centrally located body fat. The effects of race, sex and age on the obesity-blood pressure relationship were analyzed.

Effectiveness of animal rotation in achieving uniform dust exposures and lung dust deposition in horizontal flow chambers.

An important source of variability of experimental results in inhalation toxicology originates from the nonuniformity of chamber concentrations. Two horizontal flow inhalation chambers were used in evaluating the effect of cage rotation within each chamber on the amount of alpha-quartz deposited in the lungs of male Fischer 344 rats. The alpha-quartz lung burden was determined by quantitative X-ray diffraction.

Time-lapse cinematographic analysis of beryllium--lung fibroblast interactions.

The proliferative response to beryllium chloride of cells in a population of human lung fibroblasts was quantitatively assessed using time-lapse cinematography. A dose of 0.02 microgram Be/ml, known to decrease the growth rate of fibroblasts, affects an estimated 75% of the cells in the population, increasing their interdivision time (IDT) by approximately 5 hr.

Depressed spontaneous cell-mediated cytotoxicity in Crohn's disease.

Cytotoxicity of peripheral blood mononuclear cells of 30 patients with Crohn's disease (CD) and 30 matched controls was assayed by measuring isotope release from 75Se-L-methionine labelled RPMI 4788 human colon cancer cells. Effector populations were studied with and without monocyte depletion after 4 and 24 hr incubations in 10% fetal calf serum or autologous serum or plasma. Cytotoxicity was negligible at 4 hr.

Respiratory symptoms and lung function in a sample of Vermont dairymen and industrial workers.

This study reviews the respiratory status of a sample of Vermont male dairy farmers, and a comparison group from industry, matched for age, sex and smoking. Survey instruments included a standardized questionnaire and simple pulmonary function tests. In general, past and present smokers had more respiratory symptoms than never-smokers; and farmers, in all smoking categories, reported symptoms with greater frequency than did their counterparts from industry.

Farmer's lung disease in Vermont.

Several Vermont population groups were surveyed for the occurrence of antibodies to thermophilic actinomycetes. Antibodies to M. faeni and T.

Metabolism of concanavalin A-affinity molecular variants of alpha-fetoprotein in rats.

Serum half-lives of unfractionated rat alpha-fetoprotein (AFP), concanavalin A (Con A)-nonreactive AFP, and Con A-reactive AFP in normal 45- to 55-day-old male and female F344 rats were determined to be 19 hours. No significant differences were seen between the half-lives of unfractionated AFP and either of the two Con A-affinity molecular variants of AFP studied. No evidence of interconversion of the Con A-affinity AFP variants during 24 hours in the circulation was found.

Sources of variance in the measurement of intrapulmonary killing of bacteria.

Sources of variability are described for a method used for the quantitative measurement of pulmonary resistance to inhaled bacteria in individual animals. Factors contributing significantly to variability include aerosol exposure chamber design, bacterial species used for aerosol challenge, location of animals in the chamber, and individual intrapulmonary bacterial killing rates. Laboratory error accounted for a small portion of the variance.

Amino acid residues of serum and CSF protein in multiple sclerosis. Clinical application of statistical discriminant analysis.

Statistical discriminant analysis of the amino acid compostion of serum and cerebrospinal fluid (CSF) proteins provides an objective method for distinguishing between normal controls and patients with multiple sclerosis (MS). This method also results in a high degree of specificity in separating MS patients from those with other diseases of the nervous system. The CSF protein serine residue is highly correlated with the CSF IgG and holds promise for a more sensitive diagnostic test for MS than the currently used CSF IgG.