Application of High-Field Superconducting Magnet to Protein Crystallization

AbstractA quasi-microgravity environment appears in a high-field superconducting magnet bore where a large magnetic force counterbalances gravity acting on a diamagnetic substance. This suppresses convection of the diamagnetic solution in the crystallization cell placed in the bore from which protein crystals precipitate.A 16 T class superconducting magnet has been developed with a special coil configuration; one of the component coils produces a magnetic field the direction of which is opposite to that of the other coils. Thus, a large magnetic field gradient occurs, creating a magnetic force large enough to levitate water and hinder convection.This magnet system is operated in persistent mode, which is adequate for a rather time-requesting crystallization process of proteins. Preliminary experiments have shown that the protein crystallization process is substantially retarded in the magnetic force field

In-situ and real-time growth observation of high-quality protein crystals under quasi-microgravity on earth

Precise protein structure determination provides significant information on life science research, although high-quality crystals are not easily obtained. We developed a system for producing high-quality protein crystals with high throughput. Using this system, gravity-controlled crystallization are made possible by a magnetic microgravity environment. In addition, in-situ and real-time observation and time-lapse imaging of crystal growth are feasible for over 200 solution samples independently. In this paper, we also report results of crystallization experiments for two protein samples. Crystals grown in the system exhibited magnetic orientation and showed higher and more homogeneous quality compared with the control crystals. The structural analysis reveals that making use of the magnetic microgravity during the crystallization process helps us to build a well-refined protein structure model, which has no significant structural differences with a control structure. Therefore, the system contributes to improvement in efficiency of structural analysis for "difficult" proteins, such as membrane proteins and supermolecular complexes

二度の手術を要した胃全摘後Roux-en-Y吻合部逆行性腸重積の1例

雑誌掲載版症例は76歳男性で,54歳時に胃癌にて胃全摘(Roux-en-Y再建).75歳時突然の上腹部痛にて受診した.CTでは上腹部の拡張腸管内に同心円状層状構造の腫瘤像を認め,イレウス管造影ではY吻合部でカニ爪様の途絶を認めた.腸重積による腸閉塞を疑い開腹した.Y吻合部より肛門側の空腸が逆行性に重積していた.整復し空腸を一部切除した.先進部分に異常は認めなかった.1年後,同様に突然の上腹部痛にて受診した.CTより腸重積症の再発と診断し開腹した.Y吻合部の逆行性腸重積症であり,Y吻合部を含めて空腸を切除,再吻合した.以後再々発は認めていない.胃切除後の腸重積症は突然の上腹部痛,嘔吐で発症し,CTでは層状構造の腫瘤像が特徴的である.先進部腸管の異常を認めることはまれで,機械的因子や機能的因子が原因として推測される.胃切除後の腸重積症はまれではあるが,術後腸閉塞の原因疾患の一つとして念頭に置く必要がある