An Attempt to Make Platelet Rich Fibrin from Bone Marrow Aspirate.

INTRODUCTION: Platelet Rich Fibrin (PRF) was developed as a new generation of platelet concentration from peripheral blood. Method to make PRF is simple. It is easy to handle with its moderate firmness. Histologically, platelets and nucleated cells are packed along the yellow-red border. Bone marrow aspirate contains bone marrow cells that potentially work for tissue regeneration, and platelets which contain growth factors. The specific gravities of them are comparable. It implies that, if it is possible to make PRF from bone marrow aspirate, then high concentration of platelets and bone marrow cells can be obtained simultaneously by taking out yellow-red interface of it. AIM: To find out a method to make PRF from bone marrow aspirate. MATERIALS AND METHODS: Iliac crest of rabbits were punctured and aspirated with or without anti-coagulant, under general anaesthesia. The bone marrow aspirate was centrifuged in glass tubes. For the bone marrow aspirate taken with anti-coagulant, calcium chloride was added just before centrifugation. Products were taken out and observed grossly. The products were fixed with formaldehyde and observed histologically. RESULTS: Coagulated gels with two-toned colour were obtained by all methods. In the gels without anti-coagulant, interfaces between two colours were obscure. Histologically, platelets and nucleated cells scattered as clusters. Filtering caused haemolysis and reduced the yield of the product. With the aspirate taken with anti-coagulant, platelets and nucleated cells formed a band along the interface. CONCLUSION: PRF can be made from bone marrow aspirate by adding anti-coagulant in aspiration and reversed with calcium chloride just before centrifugation.

A new rabbit model of impaired wound healing in an X-ray-irradiated field.

Radiation is an important therapy for cancer with many benefits; however, its side effects, such as impaired wound healing, are a major problem. While many attempts have been made to overcome this particular disadvantage, there are few effective treatments for impaired wound healing in an X-ray-irradiated field. One reason for this deficiency is the lack of experimental models, especially animal models. We have previously reported a mouse model of impaired wound healing in which the irradiation area was restricted to the hindlimbs. In this mouse model, due to the size of the animal, a diameter of five millimeters was considered the largest wound size suitable for the model. In addition, the transplanted cells had to be harvested from other inbred animals. To investigate larger wounds and the impact of autologous specimen delivery, a rabbit model was developed. Rabbits were kept in a special apparatus to shield the body and hindlimbs while the irradiation field was exposed to radiation. Six weeks after irradiation, a 2 x 2 cm, full-thickness skin defect was made inside the irradiation field. Then, the wound area was observed over time. The wound area after irradiation was larger than that without irradiation at all time points. Both angiogenesis and collagen formation were reduced. For further study, as an example of using this model, the effect of autologous platelet-rich plasma (PRP) was observed. Autologous PRP from peripheral blood (pb-PRP) and bone marrow aspirate (bm-PRP) was processed and injected into the wounds in the irradiated field. Two weeks later, the wounds treated with bm-PRP were significantly smaller than those treated with phosphate buffer vehicle controls. In contrast, the wounds treated with pb-PRP were not significantly different from the controls. This rabbit model is useful for investigating the mechanism of impaired wound healing in an X-ray-irradiated field.

An augmented reality system in lymphatico-venous anastomosis surgery.

Indocyanine green lymphography, displayed as infrared image, is very useful in identifying lymphatic vessels during surgeries. Surgeons refer the infrared image on the displays as they proceed the operation. Those displays are usually placed on the walls or besides the operation tables. The surgeons cannot watch the infrared image and the operation field simultaneously. They have to move their heads and visual lines. An augmented reality system was developed for simultaneous referring of the infrared image, overlaid on real operation field view. A surgeon wore a see-through eye-glasses type display during lymphatico-venous anastomosis surgery. Infrared image was transferred wirelessly to the display. The surgeon was able to recognize fluorescently shining lymphatic vessels projected on the glasses and dissect them out.