| Project/Area Number |
16590535
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Legal medicine
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
IWADATE Kiminaru Tokyo Medical and Dental University, Graduate School, associate professor, 大学院・医歯学総合研究科, 助教授 (90251222)
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| Project Period (FY) |
2004 – 2005
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| Project Status |
Completed (Fiscal Year 2005)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 2005: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 2004: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | milk aspiration / immunohistochemistry / sudden infant death / murine model |
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| Research Abstract |
Our experiments were carried out on 8-week-old Wistar rats. Between 50μl and 1.0ml of cow's milk was injected either intravitally or postmortemly into the trachea of rats. The lungs and other organs were removed from immediately to 2 weeks after injection. Specimens from each organ were obtained fixed in 10% formaldehyde solution and embedded in paraffin. Sections 2-3μm thick were prepared. Immunostaining were performed using the Histfine rat kit (Nichirei). The results of immunostaining with anti-human α lactalbumin antibody and anti-cow whey antibody (DAKO) indicated that intravitally aspirated milk was distributed in the lungs more widely than postmortemly injected milk. However, the difference between them was not significant enough that they could be clearly distinguished by pathological findings alone. Regardless of the amount of instilled milk and of the time interval from the instillation of milk to removal of the lungs, milk was detected in peripheral alveoli in all of the rats of both groups. This result indicates that where the aspirated milk finally reaches is not the criterion for the judgment of intravital or postmortem aspiration. As the lungs removed immediately after milk injection showed almost the same pathological findings as those removed 1 hour after injection even in the intravital aspiration group, the distribution of aspirated milk in the lungs may be strongly influenced by gravity during the period of formalin fixation.
As for organs other than the lungs, renal tubules and macrophages in spleen showed positive staining against anti-α-lactalbumin antibody, suggesting that components of aspirated milk likely enter the blood stream via capillaries of the alveolar wall. Immunohistochemical detection of aspirated milk in the kidneys may provide proof of intravital milk aspiration.
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