2006 Fiscal Year Final Research Report Summary
Analysis of unknown cryogens existing in the blood of a hypothermic patient
| Project/Area Number |
16390060
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Environmental physiology (including Physical medicine and Nutritional physiology)
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| Research Institution | Shimane University |
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Principal Investigator |
SHIDO Osamu Shimane University Faculty of Medicine, Environmental Physiology, Professor, 医学部, 教授 (40175386)
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| Co-Investigator(Kenkyū-buntansha) |
HASHIMOTO M Shimane University Faculty of Medicine, Environmental Physiology, Associate Professor, 医学部, 助教授 (70112133)
TSUCHIYA M Shimane University Faculty of Medicine, Medical Biochemistry, Professor, 医学部, 教授 (90188582)
WATANABE T Tottori University Faculty of Medicine, Functional, Morphological and Regulatory Science, Professor, 医学部, 教授 (60182929)
IMOTO T Tottori University Faculty of Medicine, Functional, Morphological and Regulatory Science, Associate Professor, 医学部, 助教授 (10109639)
KOIZUMI S Kanazawa University Graduate School of Medical Science, Angiogenesis and Vascular Development, Professor, 大学院・医学研究科, 教授 (50019973)
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| Project Period (FY) |
2004 – 2006
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| Keywords | hypothermia / cryogen / Protein / thermoregulation |
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| Research Abstract |
We further attempted to identify unknown cryogen(s) existing in the blood of a hypothermic patient. The patient's serum was divided into two fractions high-hydrophobic (HA) and low-hydrophobic fractions (LA), with a commercial column for hydrophobic affinity chromatography. The amount of albumin in the LA fraction was 1/5 of that in the HA fraction. When each fraction was injected into rats, it produced clear hypothermia in one out of 3 rats. Gel electrophoresis of the LA fraction showed that the presence of bands which were not seen in the serum of healthy controls. Then, the bands was taken and directly analyzed by mass spectrometry. According to the search of human genome database, fragments of two types of proteins were identified in the band. The twp types of proteins (named A and B) were treated with trypsin and the samples were injected into rats. Intraperitoneal injections of the trypsin-treated protein A produced hypothermia in 2 rats out of 5. Gel electrophoresis of the sample showed the presence of bands which were peculiarly seen in the hypothermic patient's serum, although the bands were slightly recognized only by silver staining. Protein A was treated with trypsin in various methods and one method overtly enhanced the specific bands in gel electrophoresis. However, the samples hardly induced hypothermia in rats. In different series of study, we investigated protease activities of the patient's serum, and observed that the activity level appeared to be greater by 2 times than that of age-matched healthy humans. It is therefore speculated that the high protease activity of the patient's serum elevates the levels of protein A catabolites, which may have a cryogenic role. However, further intensive studies are needed to identify the cryogens existing in the hypothermic patient's blood.
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