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Biomedical subjects

J F Brown

Publications and source records attributed to J F Brown.

94 records · Page 6Linked to original sources
PubMedDate not supplied

Behavioral and neurological effects of symptomatic and asymptomatic lead exposure in children.

Forty-five children 4 to 8 yr of age who had been exposed to environmental lead were studied, consisting of an acute encephalopathy group and groups with short- and long-term exposure but without encephalopathy. Control children were matched for age, sex, race, and socioeconomic status with lead-exposed subjects, but lived in post-1945 housing and had negative neurological history and blood tests. The encephalopathy group had a significantly higher incidence of neurological deficits, retarded mental development, and higher hyperactivity than control subjects. Children with short- and long-term exposure short of encephalopathy were somewhat inferior to matched control subjects, but not to a statistically significant extent.

Child↗
PubMedDate not supplied

Comparability and precision of serum PCB measurements.

The 95% prediction interval for single measurements of serum "Aroclor" reported by a reputable commercial analyst was found to be approximately +/- 42%. The geometric mean serum PCB levels in a population of capacitor workers who had formerly had direct exposure to the commercial PCBs--Aroclors 1016, 1242, and 1254-were found to be alternatively reportable as 1905 ppb minimum initial PCBs (as calculated from most persistent peaks present); 1093 ppb non-overlapping analytical "Aroclor" levels (as calculated by the conventional sum-of-the-peak-heights method); 303 ppb total PCBs actually present; or 19 ppb "human PCB" (as calculated by the NHMP procedure). The broad spread in reportable values was relatable to the PCB isomer distribution and clearance patterns in the occupationally exposed population.

Adult↗
PubMedDate not supplied

Maternal hypothyroxinemia: psychoneurological deficits of progeny.

Maternal thyroid function was evaluated clinically, by reproductive history, and by serial measurements of serum butanol-extractable iodine (thyroxine-like iodine), two before and two after 24 gestational weeks during 1,349 pregnancies. Three percent of the women were hypothyroxinemic. Developmental, intellectual, and motor abilities of progeny born to (Group I) 210 euthyroxinemic, (Group II) 15 hypothyroxinemic given adequate thyroid replacement therapy, and (Group III) 21 inadequately treated hypothyroxinemic women were compared. The groups of mothers exhibited no significant differences in intelligence, years of education, or chronological age. Mean developmental and intellectual scores at eight months, four and seven years of Group II progeny evidenced remarkably consistent similarity to scores of siblings and controls. At each age, mean developmental and intellectual scores were lower for Group III progeny, and motor scores of the latter were lowest. Some progeny of Group II mothers, treated only after 12 or 29 weeks, failed the ball catch and line walk tests; some had strabismus and other ocular disturbances. Could these deficits have originated with maternal hypothyroxinemia during first semester weeks before the thyroid-pituitary axis matures? Now in 1990-1991, early findings fit into the modern concepts of significant maternal gestational transfer of thyroxine to the fetus. The authors encourage prenatal and/or early gestational screening for maternal hypothyroxinemia and urge prescription of adequate thyroid replacement therapy for hypothyroxinemic women.

Adolescent↗