Polycyclic aromatic hydrocarbons (PAHs) and dioxins are lipophilic organic pollutants occurring widely in the terrestrial environment. In order to study the PAHs and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) transfer in the food chain, pigs have been fed with milk mixed either with 14C-phenanthrene, with 14C-benzo[a]pyrene or with 14C-TCDD. The analysis of portal and arterial blood radioactivi...

We examined the ability of erucic acid (22:1n-9) to cross the blood-brain barrier (BBB) by infusing [14-14C]22:1n-9 (170 microCi/kg, iv and icv) into awake, male rats. [1-14C]arachidonic acid (20:4n-6) [intravenous (i.v.)] was the positive control. After i.v. infusion, 0.011% of the plasma [14-14C]22:1n-9 was extracted by the brain, compared with 0.055% of the plasma [1-14C]20:4n-6. The [14-14C...

This study examines the consequences on cerebral polyamine biosynthesis of increases and decreases in cerebral methylation. Increases were elicited by administering the convulsant agent methionine sulfoximine (MSO) and decreases by elevating in vivo the cerebral levels of the methylation inhibitor S-adenosylhomocysteine. Following the intraventricular (i.vt.) administration of one of the two po...

Continuous 14C 0 2 Evolution, Glycolytic Compartment, Pyruvate Metabolism, Synchronous, Yeast The different metabolic behaviour of endogenously produced [1-14C] pyruvate derived from [3,4-14C]glucose and of exogenously added [1-14C]pyruvate were studied with synchronous yeast cell populations, under conditions which differentially influenced the activities of pyruvate decarboxylase in the cytop...

Radiocarbon activities were measured in annual tree rings for the years 2009 to 2015 from Japanese cedar trees (Cryptomeria japonica) collected at six sites ranging from 2.5-38 km northwest and north of the Fukushima Dai-ichi nuclear power plant. The 14C specific activity varied from 280.4 Bq kg-1 C in 2010 to 226.0 Bq kg-1 C in 2015. The elevated 14C activities in the 2009 and 2010 rings confi...

Wood, Stjernholn & Leaver (1955) have proposed that propionic acid fermentation may involve the simultaneous occurrence of the Embden-Meyerhof cleavage and a second, undetermined, cleavage. The suggestion was based on the distribution of 14C in the products obtained by fermenting [1-14C]glucose, [2-l"C]glucose, [6-14C]glucose and [3:4-14C]glucose with cell suspensions. No matter which carbon at...

1. 14C-labelled lysine, glutamic acid and methionine were each administered as single infusions through catheters in the jugular veins of pigs between 28 and 42 d old, receiving either a low-protein (LP) (140 g protein/kg), or a high-protein (HP) (200 g protein/kg) diet. The pigs received 40 g diet/kg body-weight per d. 2. L-[U-14C]lysine and L-[U-14C]glutamic acid were both rapidly removed fro...

A remarkable discovery made over the past twenty-five years is that organic samples from every level in the Phanerozoic portion of the geological record, when tested by highly sensitive accelerator mass spectrometer (AMS) methods, display significant and reproducible amounts of 14C. Because the lifetime of 14C is so brief, these AMS measurements pose an obvious challenge to the standard geologi...