FDA Perspective on and Response to the Risk of Hepatitis A from Blood Products

The clinical and laboratory data available on hepatitis A virus infections reported in Europe were reviewed by the Blood Products Advisory Committee of the Food and Drug Administration. The panel's consensus was that the clotting factor concentrates currently available in the United States are safe with respect to viral diseases, hepatitis A transmissions do not appear to be a significant health problem, and there is a paucity of epidemiologic data on hepatitis A in patients with hemophilia in the United States.     

Stephen Girard (1750–1831): a one-eyed American patriot

Stephen Girard trader, banker, millionaire, and patriot lived 81 full and exciting years. Apparently born with a blind or amblyopic right eye, he emigrated from Bordeaux. France, via Santa Domingo to the United States, and finally settled in Philadelphia, where he developed a successful maritime trade. Ultimately, Girard became the first multimillionaire in the United States. Extremely generous, he often walked from his home in the center of Philadelphia to his farm in what is now South Philadelphia distributing shoes to needy children. Probably Girard’s most heroic gestures were his gallant fight against the yellow fever epidemic in 1793 and his loan to the U.S. government during the War of 1812, which allowed the bankrupt country to continue the conflict and ultimately to win the war. Presented, in part, at the tenth annual meeting of the David G. Cogan Ophthalmic History Society, the College of Physicians of Philadelphia, March 8 and 9, 1997.     

Characterization and prediction of gradient acoustic noise in MR imagers

Gradient acoustic noise has been measured and characterized for an epoxy-potted, shielded gradient assembly in a 1.5 T MRI system. Noise levels vary by 10 dB or more as a function of longitudinal position in the scanner and reflect the pattern of forces applied to the gradient assembly. The noise level increases slightly (1–3 dB) with a patient in the scanner. The spectrum of the noise is similar (but not identical) to the spectrum of the input signal. A gradient-pulse-to-acoustic-noise transfer function was obtained by using a white noise voltage input to the gradient system. The transfer function enabled us to accurately predict acoustic noise output for a pulse sequence consisting of a series of trapezoidal pulses on a single axis and for a clinical fast spin echo sequence with gradients present on all three axes.     

Methylmercury poisoning: Long-term clinical,radiological, toxicological,and pathological studies of an affected family

For 3 months in 1969 a family in the United States that included a pregnant mother consumed pork containing methylmercury. Children, aged 20, 13, and 8 years and a neonate, developed severe neurological signs. Twenty-two years later, the 2 oldest had cortical blindness or constricted visual fields, diminished hand proprioception, choreoathetosis, and atentional deficits. Magnetic resonance images showed tissue loss in the calcarine and parietal cortices and cerebellar folia. The youngest had quadriplegia, blindness, and severe mental retradation until their deaths. The brain of the 8-year-old who died at age 30 showed cortical atrophy, neuronal loss, and gliosis, most pronounced in the paracentral and parietooccipital regions. The total mercury level in formalin-fixed, left occipital cortex was 1,974 ng/gm as measured by atomic absorption. Regional brain mercury levels correlated with extent of brain damage. A control patient had 38.5 ng of mercury/gm in the occipital cortex. Systemic organs in the patient and a control subject had comparable mercury levels. In mercury-intoxicated rats, we found that only 5 to 10% of total brain mercury was lost by formalin fixation. Brain inorganic mercury in the patient ranged from 82 to 100%. Since inorganic mercury crosses the blood-brain barrier poorly, biotransformation of methyl to inorganic mercury may have occurred after methylmercury crossed the blood-brain barrier, accounting for its persistence in brain and causing part of the brain damage.