twentiethcentury2txt

The work of Bohr et al. (1904) is cited here as representative of one of
several possible biofeedback mechanisms that maintain the highest rate
of aerobic metabolism in the brainstem nuclei of high metabolic rate.
The Bohr effect is the name given to the property of hemoglobin that
releases oxygen to tissues in exchange for carbon dioxide.

Tissues such as the auditory nuclei of the brainstem generate more
carbon dioxide than less metabolically active areas of the brain. In
hypoxic conditions the auditory nuclei receive oxygen at the expense of
other areas such as the cerebral cortex. On the other hand, in extreme
situations such as asphyxia or poisoning by a toxic substance the
auditory system will sustain the greatest damage if resuscitation is
possible and survival follows. Tigerstedt (1911) summarized Bohr’s work
in his article eulogizing Bohr’s untimely death. Christian Bohr was the
father of Niels Bohr, who achieved even greater fame for describing
electron energy states in atoms.

Other advances in biochemistry gained importance during this period.
Enzyme catalysis of biochemical processes became understood, and
hormones such as insulin and secretin were discovered. Shimazono
(1910) described lesions of the brainstem and spinal cord found in
victims of the disease beriberi which became epidemic after refined white
rice replaced the whole grain as the staple of the diet in countries like
Japan. The discovery that extracts of the rice-germ, from polishings
removed during refinement, added back to the diet were curative led
eventually to the discovery of thiamine and its functions as a cofactor for
enzymes of aerobic energy production (Carpenter 2000).

Salvarsan, a compound containing arsenic, was developed early in the
twentieth century by Ehrlich as a treatment for syphilis. Salvarsan was
discovered through a systematic search for anti-syphilitic agents. This
gave impetus to the quest for other chemicals that could act as "magic
bullets" for specific infections. Noguchi (1913) was the first to observe
the spirochete bacterium, Treponema pallidum, responsible for syphilis
in the brains of people with the illness known as “dementia paralytic” or
general paresis. Southard and Solomon (1917) described 137 cases of
this disorder, which is rarely if ever seen anymore because of the
availability of penicillin. It would be thirty years before the magic-bullet
penicillin would become available.