title: X-ray diffraction from a left ventricular wall of rat heart.
abstract: We studied x-ray diffraction from the left ventricular wall of an excised, perfused whole heart of a rat using x rays from the third-generation synchrotron radiation facility, SPring-8. With the beam at right angles to the long axis of the left ventricle, well-oriented, strong equatorial reflections were observed from the epicardium surface. The reflections became vertically split arcs when the beam passed through myocardium deeper in the wall, and rings were observed when the beam passed into the inner myocardium of the wall. These diffraction patterns were explained by employing a layered-spiral model of the arrangement of muscle fibers in the heart. In a quiescent heart with an expanded left ventricle, the muscle fibers at the epicardium surface were found to have a (1,0) lattice spacing smaller than in the rest of the wall. The intensity ratio of the (1,0) and (1,1) equatorial reflections decreased on contraction with a similar time course in all parts of the wall. The results show that it is possible to assign the origin of reflections in a diffraction diagram from a whole heart. This study offers a basis for interpretation of x-ray diffraction from a beating heart under physiologically and pathologically different conditions.
authors.affiliation: SPring-8/JASRI, Sayo, Hyogo 679-5198, Japan. yagi@spring8.or.jp
authors.forename: Naoto
authors.initials: N
authors.lastname: Yagi
authors.forename: Juichiro
authors.initials: J
authors.lastname: Shimizu
authors.forename: Satoshi
authors.initials: S
authors.lastname: Mohri
authors.forename: Jun'ichi
authors.initials: J
authors.lastname: Araki
authors.forename: Kazufumi
authors.initials: K
authors.lastname: Nakamura
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Okuyama
authors.forename: Hiroko
authors.initials: H
authors.lastname: Toyota
authors.forename: Taro
authors.initials: T
authors.lastname: Morimoto
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morizane
authors.forename: Mie
authors.initials: M
authors.lastname: Kurusu
authors.forename: Tatsushi
authors.initials: T
authors.lastname: Miura
authors.forename: Katsushi
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Tsujioka
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Suga
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Kajiya
mesh_terms: D000818:Animals; D006352:Heart Ventricles; D008962:Models, Theoretical; D009119:Muscle Contraction / Q000502:physiology*; D018485:Muscle Fibers, Skeletal / Q000737:chemistry / Q000166:cytology*; D009132:Muscles / Q000737:chemistry / Q000166:cytology*; D009206:Myocardium / Q000737:chemistry / Q000166:cytology*; D051381:Rats; D017208:Rats, Wistar; D014961:X-Ray Diffraction / Q000379:methods*