Effect of normal human erythrocytes on blood rheology in microcirculation.

BACKGROUND: Effects of RBCs on blood rheology were studied using a microchannel array flow analyzer (MC-FAN). METHODS: Fluidity of four types of samples prepared from the venous blood of healthy volunteers was examined in terms of passage time through the microchannel array of MC-FAN (model KH-3): (1) physiological saline-RBC suspensions and plasma-RBC suspensions, each adjusted to a predetermined hematocrit value; (2) suspensions of glutaraldehyde-treated hardened RBCs; (3) fibrinogen-RBC and albumin-RBC suspensions; and (4) dextran-RBC suspensions. RESULTS: Hematocrit positively correlated with passage time. Both plasma and fibrinogen prolonged passage time significantly. Hardened RBCs completely obstructed the microchannel. The passage time of dextran-RBC suspensions was prolonged in a dextran molecular weight- and concentration-dependent manner and was dependent on the passage time of the solution alone. CONCLUSIONS: Blood rheology, as determined by MC-FAN, is affected not by RBC aggregation but hematocrit, RBC deformability, and the passage time of the solution.

A case of ileoileal intussusception caused by metastatic pedunculated tumor of cutaneous angiosarcoma.

Cutaneous angiosarcoma is a rare aggressive vascular tumor that occurs in elderly patients and is usually located on the head and face. Metastases often develop in the cervical lymph nodes, lungs, bone, liver and spleen. There have been no reports of ileoileal intussusception due to metastatic tumor from cutaneous angiosarcoma. We reported a case of cutaneous angiosarcoma in a 67-year-old Japanese male accompanied with ileoileal intussusception due to metastatic angiosarcoma. We assume that the metastatic tumor in the small intestine was metastasized hematogeneously from cutaneous angiosarcoma, resulting in the formation of nodules and the rapid growth of a pedunculated tumor as a forerunner of the ileoileal intessusception.