Peter Proctor

Peter H. Proctor, PhD, MD is an American pharmacologist, toxicologist, biophysicist and physician. He has worked in neuroscience and biological psychiatry, organic electronics, pharmacology/toxicology, as well as free radical and oxidative stress research. He pioneered aspects of redox signaling, which is the concept that reactive oxygen species, other electronically activated molecules, and solid-state electronic processes are involved in cell signaling.
Education and professional career
Proctor graduated from Rice University and received his Master and PhD degrees from the University of Texas Health Science Center at Houston. He received his medical degree from University of Texas Medical Branch at Galveston.
Research
Proctor is the author of research publications, book chapters, and presentations. He also holds pharmaceutical patents, e.g., for the use of nitrone and nitroxide drugs in the treatment of radiation dermatitis and alopecia, as well as (among other indications)fibrocystic disease of breast and neuropathic pain. Some of his drugs are currently in clinical trials.
Psychiatry and neuroscience
Beginning in 1970, Proctor and his coworkers proposed a fundamental role for electron-transfer processes (including free radicals, redox signaling and oxidative stress) in a variety of neuropsychiatric disorders, including schizophrenia. For example, they noted the common association of oxidative stress with specific clusters of symptoms in humans diseases These symptoms include psychosis, dyskinesia, pigmentation abnormalities, and deafness. This association was later extended to include, e.g., diabetes, inflammation, and fibrosis. Likewise, they postulated an underlying common etiology involving electronically activated processes in such symptomology. Oxidative stress and redox signaling are now an important area of research in psychiatry and neuroscience, as well as general disease pathogenesis
Proctor has also published in the area of stroke concerning oxidative stress in ischemic injury and its application to neuroprotection, an area pioneered by his co-worker Harry Demopoulos. For example, NXY-059 or Cerovive is the disulfonyl derivative of Proctor's patented drug PBN (phenylbutylnitrone). After showing significant efficacy in the first wing of its phase-3 clinical trial for the treatment of stroke, Cerovive failed the second wing. The failure of this trial wiped several billion dollars off the net asset value of the drug company AstraZeneca. Proctor and Tamborello suggested that the effective agent in the first stroke-treatment trial was a pharmacologically active breakdown product of NXY-059, MNP or "methylnitrosopropane", to which he also holds patent claims. They further propose that stabilization of Cerovive to prevent such breakdown was responsible for the failure of the second trial.
Similarly, Proctor has explained the puzzling repeated failure in human trials of neuroprotective agents and antioxidants effective in animals by noting the uniquely high endogenous levels of the antioxidant neuroprotectant uric acid in humans In summary, high levels of uric acid leave little "therapeutic room" for analogous extracellular neuroprotectants to work in humans. Following up, Proctor suggested the use of birds, which also have high urate levels, in the future screening of agents to prevent and treat ischemic injury.
Likewise, by studying its semiconductor properties, Proctor and his associates helped clarify the function of neuromelanin in the human brain. Melanized neuronal tracts such as in the substantia nigra and locus caeruleus figure in the etiology of most Axis-I psychiatric disorders. This includes schizophrenia, bipolar disorder, depression, and drug dependency. Concerning Proctor's work with melanin, Hill's review notes: “...Aside from camouflage, its other roles can be brought together by a unifying hypothesis as first proposed by Proctor and McGinness nearly 20 years ago...”
Uric acid
Uric acid is a strong reducing substance present in uniquely high levels in human blood. In a 1970 paper in the journal Nature Proctor suggested that in primates uric acid partially substitutes for another strong reducing substance, ascorbic acid (vitamin-C), e.g., as an antioxidant and enzyme cofactor. Uric acid is now thought to be the major blood antioxidant. Similarly, in 1972, Proctor reported the conditional pro-oxidant properties of uric acid and further proposed that oxidative stress figures in the pathogenesis of hyperuricemic syndromes in general. Subsequent researchers have confirmed the putative role of urate-induced oxidative stress in many human diseases. These include stroke and atherosclerosis, as well as gout, metabolic syndrome, diabetes, and hypertension. Similarly, the antioxidant role of uric acid is thought to figure in Parkinsonism, stroke and multiple sclerosis. A clinical trial is now underway using uric acid as an antioxidant neuroprotectant in acute ischemic stroke
.
Redox signaling
Redox signaling is the concept that electronic processes figure in cell signalling. With respect to "solid state" electronic processes in biomaterials, the concept of redox signaling is generally credited to Albert Szent-Gyorgyi. In his review of molecular electronics, Hush credits Proctor's research group with the first experimental confirmation of Szent-Gyorgyi's conjectures concerning semiconductor mechanisms in cellular signaling, noting “Also in 1974 came the first experimental demonstration of an operating molecular electronic device that functions along the lines of the biopolymer conduction ideas of Szent-Gyorgi.” Bettinger et al. reiterates their priority in the development of biopolymer-based organic electronic devices.
Expanding on Szent-Gyorgi, Proctor and coworkers further proposed that not only semiconductor processes, but electronically activated molecules in general function in redox cell signaling, e.g., in neurotransmission and inflammation. One example is the neurotransmitter action of dopamine. Organic electronics is now generally considered part of nanotechnology and nanoelectronics.

This apparatus is now in the Smithsonian Chip collection of pioneering and historic electronic devices. Proctor and his associates were also one of several groups reporting highly conductive linear backbone organic polymers well before their 1977 investigation by Shirakawa et al.

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