ABSTRACT
The present study investigated microcirculatory characteristics of the cerebral neovasculature induced in mice, using basic fibroblast growth factor (bFGF) and platelet derived growth factor (PDGF). The nylon-mesh sandwich (collagen gel/growth factor in bovine serum albumin embedded in between two nylon-mesh pieces) was used to induce angiogenesis. After different days of incubation, the observations of neocapillaries were done on the upper surface of the nylon-mesh, using fluorescence video-microscopy. The neocapillary diameter, red cell velocity, and the neocapillary density were evaluated based on the video-image. The neocapillaries were visible on the upper surface of the mesh on the 6th day after the incubation, and red cells started to flow from the day 7. The neocapillary red cell velocity increased with days after incubation, but its level was less than that of the pre-existing capillaries. The neocapillary diameter decreased as the neocapillaries got matured. The neocapillary density was dependent on the doses of bFGF and PDGF. The neocapillary diameter did not alter with the higher concentration as well as with different growth factors. Both bFGF and PDGF showed an increase in red cell velocity at high concentration.
Subject(s)
Cerebral Cortex/blood supply , Cerebrovascular Circulation , Neovascularization, Physiologic , Animals , Capillaries/ultrastructure , Cattle , Collagen , Fibroblast Growth Factor 2/pharmacology , Gels , Image Processing, Computer-Assisted , Male , Mice , Mice, Inbred C57BL , Microcirculation , Microscopy, Fluorescence , Microscopy, Video , Neovascularization, Physiologic/drug effects , Platelet-Derived Growth Factor/pharmacology , Prostheses and Implants , Serum Albumin, Bovine/pharmacology , Skin Window Technique , Surgical MeshABSTRACT
Hyperthermia and its effect on tissues are topics of great interest to scientists working in the area of radiation biology and medicine. It has been shown by many workers, that blood flow in malignant tissue displays a different response to heating than that in normal tissue. Initially, the blood flow in tumour tissue is greater than that in normal tissue, and when heat is applied there is an increase in blood flow. The extent of the increase in flow with increasing temperature is greater in normal tissue than in tumour tissue. In our laboratory we studied the effect of temperature on skin blood flow. The skin overlying tumour tissue was compared with skin with no underlying abnormality in cancer patients, and with the skin in healthy control subjects. The instrument used was a Laser Doppler Perfusion Monitor, Pf3 (Perimed, Stockholm, Sweden). We found that the skin overlying tumour tissue showed higher basal perfusion than the skin at the contralateral site with no underlying abnormality. The skin above tumour tissue showed a reduced perfusion response to an increase in temperature (vascular sluggishness) compared to skin at the contralateral site and skin in healthy controls. The reduction in thermal response depends on the size of the tumour.
