Biomedical subjects

D Velkou

Publications and source records attributed to D Velkou.

3 recordsLinked to original sources

PubMed1985

Experimental microvascular polytetrafluoroethylene grafts: 6-month patency.

The efficacy of 1-mm internal-diameter polytetrafluoroethylene as a microvascular prosthesis is unclear. In this study, 8-mm-long segments of this material were implanted into the femoral arteries of 30 rats. Animals were examined every 2 weeks up to 6 months by Doppler ultrasound. Cumulative patency by the life-table method was 86.7 percent at 6 months. There were 26 patent grafts, 2 occlusions, and 2 deaths. Intimal hyperplasia adjacent to the anastomoses was seen in the native arteries. The pseudointima lining the grafts was cellular near the anastomoses but usually acellular in midgraft regions. It is concluded that if early failure does not occur, then good long-term patency is possible with 1-mm polytetrafluoroethylene in this setting and that patency is not dependent on development of a cellular pseudointima. Longer graft segments should be evaluated in future studies.

Actuarial Analysis↗

PubMed1984

One millimetre polytetrafluoroethylene (Gore-Tex) as a microvascular prosthesis: technique and early patency.

We have described a technique for grafting 1 mm internal diameter polytetrafluoroethylene (Gore-Tex) to the rat femoral artery. By spatulating the ends of the recipient artery and completing the proximal anastomosis before commencing the distal one, gentle and accurate suture placement is assured. At a mean of 40 days postoperatively (range 35-42 days) 16 of 20 Gore-Tex grafts (80%) were patent compared with 17 of 20 autogenous femoral vein grafts (85%). Examination of the prosthetic grafts by light microscopy and scanning electron microscopy showed incomplete development of a cellular lining and some areas of neo-intimal hyperplasia. One millimetre Gore-Tex provides excellent early patency as a microvascular graft in this experimental setting but long term patency is still undetermined.

Animals↗

PubMed1983

Neural crest ablation and limb morphogenesis.

Left caudal neural crest was ablated by diathermy in 2-day-old chick embryos, to injure the region of sensory sciatic innervation before the appearance of the hind-limb bud. Embryos were fixed immediately, 24 hr and 14 days later, for examination of the effects of the ablation upon neural crest, neural tube, somitic mesoderm, and subsequent limb development. All embryos examined immediately and at 24 hr after ablation showed damage to the left neural crest, but the injury extended deeper into neural fold or tube, across the midline, and into somitic mesoderm. Of 17 chicks which survived to 16 days, 7 had gross deformity of the left leg and 10 had morphologically normal legs. Deformed chicks had a significant reduction in the mass of dorsal root ganglia on the operated side but no reduction in the area of the spinal cord. Operated chicks without limb deformities showed reduction of spinal cord but not of dorsal root ganglia. This suggests that limb morphogenesis may be quantitatively related to neural crest but not to neural tube. This possibility is considered in the light of previous publications. However, the experimental limitation of the diathermy method leaves the final conclusion open to interesting speculation and to future examination by improved experimental design.

Animals↗