A biomagnetic assessment of colonic electrical activity in pigs

Abstract

The electrical control activity of the large intestine was recorded in six pigs using a SQUID magnetometer. The study was performed in pre- and post-colectomy/sham-colectomy conditions. The biomagnetic field associated with colonic ECA changed drastically in subjects that underwent the colectomy procedure, whereas the signal for the control animals was nearly unchanged. Power spectral analysis was used to determine the average changes of dominant frequency and amplitude between baseline versus colectomy and sham-colectomy conditions. The dominant frequency was increased by 68 +/- 24% (versus 2 +/- 3% in control). The amplitude was decreased by 69 +/- 24% (versus 13 +/- 17% in control). This is the first study of transabdominal magnetic fields associated with colonic ECA, suggests some of the side effects generated in colectomy surgery and shows the utility of the biomagnetic technique in studies of the large intestine.

Antioxidant and Antiproliferative Activities of Leaf Extracts fromPlukenetia volubilisLinneo (Euphorbiaceae)

“…Because radical oxidation of substrates occurs through a chain reaction involving three stages (i.e., initiation, propagation, and termination), antioxidants show their effects through various mechanisms [36]. Thus, we used different methods to evaluate the effect of extracts on initiation (total antioxidant capacity, DPPH and reducing power), propagation (iron chelating), and termination (superoxide and hydroxyl radical scavenging activities) stages.…”

Lung cancer biomarkers for the assessment of modified risk tobacco products: an oxidative stress perspective

“…Importantly, variation in anti-oxidant levels has been associated with increased risk of developing cancer (Serafini et al, 2006; Stephens et al, 2009) and differs between smokers and non-smokers (Aycicek & Ipek, 2008; Bloomer, 2007; Buico et al, 2009). The use of TAC as a biomarker, however, may be criticised: in vitro and in vivo results are discordant (Somogyi et al, 2007); the results also vary across different TAC assays (Cao & Prior, 1998); and additionally, oxidation sources, targets and measurements differ across assays used in plasma (Somogyi et al, 2007). In most intervention trials, dietary supplementation did not alter TAC, which was possibly explained by the effect of endogenous anti-oxidants (Collins, 2005).…”