Bert M. Tolbert

A tracer study with O18 in Photosynthesis by activation analysis

A method has been devised for tracer studies with oxygen using paper chromatography and proton activation of O/sup 18/ to F/sup 18/. This technique is relatively simple and can detect a fraction of a mu g of O/sup 18/, as well as giving some information about the chemical nature of the compound into which it is incorporated. The procedure has been applied to a preliminary study of the path of O/sub 2/ in green algae. Three short-term photosynthesis products containing O/sup 18/ were observed.

Carbon‐14 Respiration Pattern Analyzer for Clinical Studies

A description of an instrument for measuring C14, percent CO2, and C14 specific activity in the breath of human subjects is presented. Ionization chamber assay for the C14 is used. The design parameters of radioactivity sensitivity and response time are discussed. For simple carbon‐14 metabolites some 1 to 10 μC are required for an eight‐hour respiration analysis with this instrument.

Ionizing Energy as an Aid in Exchange Tritium Labeling

The tritium labeling of organic compounds by the Wilzbach technique—that is, by simple exposure of the compound to tritium gas—is greatly accelerated by the simultaneous exposure of the system to a silent electrical discharge. The incorporation of tritium into benzene was increased by a factor of about 104 without undue decomposition. Cobalt-60 γ-rays were found to be far less useful for increasing the tritium incorporation.

THE EFFECT OF DEUTERIUM OXIDE ON SURVIVAL OF MICE WITH ASCITES TUMOR

Abstract The effect of deuterium oxide (D 2 O) on the survival of mice inoculated with Ehrlichs mouse ascites tumor has been studied. Mice maintained on 25% and 30% D 2 O drinking water showed an improved survival time of about 6 days, whereas 40% D 2 O drinking water had no effect on survival time. The effect is interpreted in terms of inhibition of tumor cell division and systemic toxicity.

Effect of coenzyme A on the metabolic oxidation of labeled fatty acids: rate studies, instrumentation and liver fractionation.

UCRL-2849 Unclassified Health and Biology UNIVERSITY OF CALIFORNIA Radiation L a b o r a t o r y B e r k e l e y , California Contract No. W-7405 -eng-48 E F F E C T O F COENZYME A ON T H E METABOLIC OXIDATION O F LABELED FATTY ACIDS: Rate Studies, Instrumentation, and Liver Fractionation B. M . Tolbert, Ann M. Hughes, M a r t h a R . Kirk, and M. Calvin A p r i l 18, 1955 P r i n t e d f o r the U. S. Atomic Energy C o m m i s s i o n

Nuclear and Electron Paramagnetic Resonance and its Application to Biology

Electron spin resonance and nuclear magnetic resonance both involve the absorption of electromagnetic radiation in the radio-frequency range. They may be considered as extensions of ultraviolet, visible, and infrared spectroscopy. They comprise a unque branch of spectroscopy in that one can vary the absorption energy levels at will, instead of having to use the energy levels nature has given. This advantage arises from the fact that one can vary the strength of the applied magnetic field and thus vary the spacing of the electronic and nuclear magnetic energy levels. No fundamental new truths have been demonstrated in biology by the use of nuclear magnetic resonance. Electron spin resonance measurements are beginning to give information from which one can construct a detailed picture of the nature of some biochemical reactions, such as reactions involving one-electron oxidation-reduction reactions or the so-called free radical reactions. The discovery by electron spin resonance of these free radicals in living material, and their correlation with biological activity, helps confirm what previously was only a hypothesis on certain types of enzymatic reactions. Studies to date employing electron spin resonance or nuclear magnetic resonance are reviewed. (91 references.) (C.H.)

Metabolism of Glycine-2-C14 in Man: V. Further Considerations of Pulmonary Excretion of C14O2.∗

Conclusion The fourth component of pulmonary excretion after the intravenous injection of glycine-2 C14 has been determined and found to have an average half time of 71.5 days. Recalculation of the half time and associated C14 excretion shows that decreasing component I has an average half time of 0.12 day and that 20.8% of the C14 is excreted with this rate process. For the others the half times and percentages are 0.97 day, 14.2%; 6.1 days, 25.6%, and 71.5 days, 25.7%.

Effects of oxygen on irradiated solid egg-white lysozyme.

Chromatographically homogeneous egg-white lysozyme has been subjected to gamma radiation in vacuo and in the presence of oxygen. Soluble active and inactive fractions from these samples have been i...

ASSAY OF BREATH CARBON-14 DIOXIDE OF HUMANS USING IONIZATION CHAMBERS

Summary An apparatus for the physical separation and purification of CO2 from human breath is described. These CO2 samples have been measured in a series of ionization chambers varying from 100 to 1500 cc. The optimum sample size was found to be 1000 cc for these unshielded-atmospheric pressure ionization chambers. With such equipment it is possible to carry out experiments in humans with as little as one microcurie of car-bon-14.

Distribution of Radioactivity in the Egg after Feeding Sodium Acetate-1-C14

Summary The data indicate that upon feeding of carboxyl-labeled sodium acetate, the activity is rapidly incorporated into all portions of the egg. The acetate is utilized immediately and a comparatively small percentage of radioactivity is diverted to the metabolic pool. Steady feeding of labeled material is required in order to maintain a high specific activity in all portions of the egg.