title: Gastric activity studies using a magnetic tracer.
abstract: A magnetic pulse generator has been set up in order to study gastric activity. Two coils 1.05 m in diameter, arranged in a Helmholtz configuration, were used. The system generated magnetic field pulses higher than 15 mT, of duration 17.3+/-1.2 ms. Measurements were performed in 11 male volunteers, with average age 29.3+/-6.4 years and body mass index 26.0+/-4.8 kg m(-2). Magnetite (Fe3O4) particles with diameters from 75 to 125 microm were used as magnetic tracers, which were mixed in 250 ml of yogurt in concentrations from 2 to 5 g. Signals were registered by using a high speed 3 axis fluxgate digital magnetometer and processed to determine the relaxation of the magnetic tracers by fitting a first-order exponential function to the data, a mean relaxation constant K = 116+/-40 s(-1) was obtained. Also, an average gastric peristaltic frequency was measured; a value of 3.2+/-0.3 cpm was determined.
authors.affiliation: Department of Biological Materials and Medical Physics, Physics Institute, University of Guanajuato, 37000 León, Gto, Mexico.
authors.forename: T
authors.initials: T
authors.lastname: Cordova-Fraga
authors.forename: J J
authors.initials: JJ
authors.lastname: Bernal-Alvarado
authors.forename: G
authors.initials: G
authors.lastname: Gutierrez-Juarez
authors.forename: M
authors.initials: M
authors.lastname: Sosa
authors.forename: M
authors.initials: M
authors.lastname: Vargas-Luna
mesh_terms: D000328:Adult; D015992:Body Mass Index; D004435:Eating; D006801:Humans; D008280:Magnetics; D008297:Male; D010528:Peristalsis / Q000502:physiology*; D013270:Stomach / Q000502:physiology*; D015014:Yogurt