silicon and Hemorrhage

Synthesis and characterization of the first mesoporous bioactive glasses (MBGs) containing tantalum are reported here, along with their potential application as hemostats. Silica MBGs were synthesized using with the molar composition of (80-x)% Si, 15% Ca, 5% P, and x% Ta. It was found that incorporation of >1 mol % Ta into the MBGs changes their physical and chemical properties. Increasing Ta content from 0 to 10 mol % causes a decrease in the surface area and pore volume of ~20 and ~35%, respectively. This is due to the increase in nonbridging oxygens and mismatch of thermal expansion coefficient which created discontinuities in the ordered channel structure. However, the effect is not significant on the amount of ions (Si, Ca, P, and Ta) released, from the sample into deionized water, for short durations (<60 min). In a mouse tail-cut model, a significant decrease in bleeding time (≥50% of average bleeding time) was found for Ta-MBGs compared to having no treatment, Arista, and MBG without Ta. Further studies are proposed to determine the mechanism of Ta involvement with the hemostatic process. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 107B: 2229-2237, 2019.

Topics: Animals; Calcium; Glass; Hemorrhage; Hemostatic Techniques; Mice; Silicon; Tantalum

A 71-year-old man who had undergone chest wall resection and reconstruction with a Dacron mesh silicone prosthesis for chondrosarcoma 23 years previously presented with a chest wall hematoma. Since the hematoma was found to increase in size over time, we performed an operation to achieve hemostasis. Operative findings showed that the prosthesis had separated into three sheets.

Topics: Aged; Anticoagulants; Bone Neoplasms; Chondrosarcoma; Hematoma; Hemorrhage; Hemostatic Techniques; Humans; Male; Plastic Surgery Procedures; Polyethylene Terephthalates; Prosthesis Design; Prosthesis Failure; Reoperation; Silicon; Surgical Mesh; Thoracic Neoplasms; Thoracic Surgical Procedures; Thoracic Wall; Time Factors; Tomography, X-Ray Computed

The passive biocompatibility of silicon-based electrode arrays was studied in feline cortical tissue. Three types of arrays were used: uncoated, coated with polyimide, and coated with polyimide over an adhesion promoter. Fifteen arrays were implanted for 24 h to determine early tissue reaction to the implantation procedure, and twelve arrays were implanted for 6 months to determine structural and material biocompatibility. Edema and hemorrhage were present around the short-term implants, but involved less than 6% of the total area of the tissue covered by the array. With chronic implants, leukocytes were rarely present and macrophages were found around roughly one-third of the tracks. Remnants of foreign material from the electrodes could be identified in less than 10% of the tracks. Gliosis was found around all tracks, forming an annulus between 20 and 40 microns thick. A capsule was not always present, and never exceeded a thickness of 9 microns. These results suggest that the implantation procedure produces limited amounts of tissue damage, and that the arrays are biocompatible. However, the arrays insulated with polyimide over a primer had significantly greater involvement of macrophages, gliosis, and capsule formation than uncoated arrays and arrays insulated with polyimide without printer, perhaps indicating a reaction to aluminum oxide in the primer.

Topics: Animals; Cats; Cerebral Cortex; Edema; Electrodes, Implanted; Hemorrhage; Lymphocyte Activation; Materials Testing; Prostheses and Implants; Silicon

Topics: Abdomen; Abdominal Muscles; Animals; Biomechanical Phenomena; Bridged Bicyclo Compounds; Bridged Bicyclo Compounds, Heterocyclic; Bridged-Ring Compounds; Collagen; Hemorrhage; Organosilicon Compounds; Rats; Silicon; Skin; Wound Healing