Robert Guthrie (microbiologist)

[3] His early research into bacterial inhibition assays came while he was employed by the Staten Island Public Health Hospital, testing antibiotic sensitivity.

[1] After the discovery of PKU as a cause of mental retardation, Horst Bickel and colleagues discovered that it could be treated successfully with a diet low in phenylalanine.

The excess phenylpyruvic acid in the urine of an individual with PKU would produce a bright green colour when reacting with the ferric chloride.

Infants do not excrete high enough concentrations of this compound to give a positive test result, thus delaying their diagnosis, and allowing irreversible damage to take place.

[1] Guthrie's disabled son had driven his interest in causes of mental retardation, the diagnosis of his niece with PKU turned his attention to preventable causes.

Others working with children who had PKU asked Guthrie to focus on a test that would allow for earlier identification, before irreversible damage had taken place.

When exposed to blood from patients affected with PKU, the high levels of phenylalanine overcame the inhibition, and bacterial growth was visible.

[1] This assay was initially developed to allow monitoring of phenylalanine concentrations in known patients on dietary treatment using serum spotted onto filter paper.

They developed bacterial inhibition assays for galactosemia and maple syrup urine disease that could be run using the same sample collection as the PKU test.

Long (D-LA) denounced the award of private patent rights on federally funded research, and said, "when the desire to make monopoly profits at the public's expense can adversely affect the health of our children, it is time to call a halt to this immoral and evil practice.