1988 Fiscal Year Final Research Report Summary
Establishment of a New Laboratory Test for Fungemia Using Horseshoe-crab Coagulation Factor G
| Project/Area Number |
61571116
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Laboratory medicine
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| Research Institution | Jichi Medical University |
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Principal Investigator |
OBAYASHI Taminori Jichi Medical School, 医学部, 講師 (60102266)
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| Co-Investigator(Kenkyū-buntansha) |
KAWAI Tadashi Jichi Medical School, 医学部, 教授 (60048957)
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| Project Period (FY) |
1986 – 1988
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| Keywords | opportunistic systemic mycosis / (1 3)- -D-glucan / coagulation factor G |
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| Research Abstract |
(1 3)-beta-d-glucan-sensitive coagulation factor g and proclotting enzyme of the horseshoe creb were fractionated by applying Tachypleus amebocyte lysate to a dextran-sulfate Sepharose CL-6B colum, and then combined with a chromogenic substrate (BOC-Leu Gly-Arg-pNA) to prepare a reagent for (1 3)-beta-D-glucan assay. This reagent showed a linear dose-dependant response to commercial (1 3)-beta-D-glucan and was sensitive enouhgh to betect a pg/ml matter of the substance with a coefficient of variation less than 4%. The assay actually reacted with various polysaccharides of pathogenic fungi including Candida albicans, Microsporum canis,Trichophyton rubrum, and Aspergillus fumigatus. Almost all glucan spiked in the blood was recovered by treating plasma with perchloric acid before hand. Then we measured a plasma glucan level in 183 immunocompromised patients wto underwent blood culture for possible sepsis. All of these patients had hematological malignancies like leukemia and malignant lymphomas as an underlying disease.
Of these, 13 had a higher concentration of glucan than normal: 4 were culture-positive for fungi (3 candidiasis and 1 cryptococosis), 4 were autopsy-verified deep mycoses (1 candidiasis, 1 aspergillosis, and 2 unidentifitied), and the other 5 were clinically diagnosed as deep mycoses because of a definite favourable response to antifungal agents. There were no culture-proven deep mycoses without high plasma (1 3)-beta-d-glucan concentration. These results showed that the present method is a highly sensitive screening for the diagnosis of opportunistic systemic mycosis. In addition, the elevated alucan levels decreased as the patients improved clinically with institution of antifungal medication. This suggests that the glucan detected by this method is derived from fungi, and that the test is useful for checking the effect of the drug as well as for following clinical course.
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