Yoshio Takagi

A simple infrared spectroscopic method for the measurement of expired 13CO2.

Abstract For the analysis of 13CO2 and 12CO2 in exhaled breath the mass spectrometer has been employed in general, but it is not convenient for clinical use and maintenance. We have been successfully performing the continuous measurement of expired 13CO2 and 12CO2 with a new analyzer using infrared spectroscopy which is easy to manipulate and maintain. This analyzer measures 12CO2 in a short cell with an absorbancy of around 2360.2 cm−1 and 13CO2 in a long cell with an absorbancy of around 2272.0 cm−1, recording the volume percentage of 12CO2 and the atom percentage excess of 13CO2. In our experiment, using a normal male rat weighing 210 g, a maximum expired 13CO2 of 1.7 atom% excess was recorded 10 min after an intraperitoneal injection of 10 mg of [13C]-sodium bicarbonate containing 49.0 atom% of the isotope.

Effects of hyperphenylalaninemia in the fetal stage on the postnatal development of fetal rat brain.

The effect of exposure at different prenatal stages to maternal hyperphenylalaninemia (HyPhe) on the somatic and neurological development of fetuses in rats was studied, with special respect to the change of relevant enzyme activities in the brain. While evident somatic damage was found only in the fetuses exposed to maternal HyPhe at a last stage of gestation, distinct mental retardation seemingly due to some irreversible damage to the brain was observed in all the treated fetuses regardless of the timing of exposure, and a significantly reduced activity of 2′, 3′-cyclic nucleotide 3′-phosphohydrolase (CNPase), a marker enzyme of myelin, was confirmed in the mantle region of the brain.