• Archives of Craniofacial Surgery
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• v.10 no.2
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• pp.127-130
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• 2009

Purpose: In an amputated auricle, a microvascular anastomosis is the best treatment of choice. But, the neartotally amputated auricle which is connected by very narrow tissue pedicle to the head, can survive by simple attachment without a microvascular anastomosis owing to the rich vascular network through the superficial temporal artery and posterior auricular artery. In cases of venous congestion resulting from a lack of vein anastomosis, medical leeches (Hirudo medicinalis) can solve the problem. We are reporting the case of a 6-year-old boy who had a neartotally amputated auricle with successful results by simple closure and medical leech treatment without a microvascular anastomosis. Methods: A 6-year-old male patient had an left auricular injury by an escalator accident. The left auricle was neartotally amputated from the temporal head with connection only by very narrow skin and subcutaneous pedicle (about 1 cm in width) at the helical root of upper and anterior part of auricle. Marginal bleeding from the avulsed auricle was noted and the arterial blood was supplied from a branch of upper auricular branch of the superficial temporal artery. The auricle was repaired by simple closure including cartilage and skin without any vascular anastomosis. After simple closure, the auricle showed good circulation with pink color. But on the 2nd day after the operation, there was a venous congestion with severe swelling, which resulted in a purplish colored auricle. The venous congestion disappeared after using medical leeches by the 5th day after the operation. Results: The repaired auricle showed aesthetically and functionally satisfactory result with normal development at the 9 months follow-up check after the operation. Conclusion: In cases of neartotally amputated auricles of children or crushing injury in which microsurgery is difficult, we can try simple closure with the use of medical leeches in treating a of venous congestion for a successful result.

• Biomolecules & Therapeutics
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• v.1 no.2
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• pp.166-170
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• 1993

Hirudin is a potent inhibitor of thrombin, which was originally obtained from the medicinal leech (Hirudo medicinalis) Now it is being produced through the recombinant technology on a large scale. Recombinant hirudin has been assayed for the anticoagulant activity by the measurement of clotting time and the inhibition of thrombin actvity using a chromogenic substrate. The assay range of partial thromboplastin time and thrombin time is within $0.2{\sim}1.0 {\mu}g/mι.$ Thrombin time is more sensitive to the measurement of clot. Ex vivo study showed the level of hirudin in rat plasma was highest in 10 min and then it was eliminated slowly. The half-life of r-hirudin was 80~110 min depending on the assay methods. Intraveneous injection of russel viper venom was used for thrombus induction combined with vents cava ligation. Inhibition of venous thrombosis was observed with i.v. hirudin. It was dependent on the concentration of hirudin.

• Journal of Microbiology and Biotechnology
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• v.1 no.4
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• pp.266-273
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• 1991

Hirudin, a 65-amino acid protein isolated from the salivary gland of the bloodsucking leech, Hirudo medicinalis, is a potent thrombin-specific inhibitor and blocks the thrombin-mediated conversion of fibrinogen to fibrin in clot formation. We have studied the gene expression and secretion of hirudin in yeast. Saccharomyces cerevisiae. A gene coding for hirudin was synthesized based on the amino acid sequence and cloned into a yeast expression vector $YEG{\alpha}-1$ containing the ${\alpha}-mating$ factor pre-pro leader sequence and galactose-inducible promoter, GALl0. Recombinant S. cerevisiae was found to secrete biologically active hirudin into the extracellular medium. The secreted recombinant hirudin was recovered from the culture medium and purified with ultrafiltration and reverse phase high performance liquid chromatography. Approximately 1 mg of hirudin per liter was produced under suboptimal culture conditions and brought to about 90% purity in two steps of purification.