The in vitro elution characteristics of vancomycin from calcium phosphate-calcium sulfate beads.

UNLABELLED: The purpose of this study was to determine the elution characteristics of vancomycin when combined with a calcium phosphate-calcium sulfate mixture to form antibiotic beads in an in vitro environment. The beads were placed in phosphate-buffered saline and kept at 36 degrees C for 6 weeks. Three separate assays were undertaken, after which the phosphate-buffered saline was assayed at 24-hour intervals. Elution of the antibiotic was sustained at a gradual rate for 22 days. The amount of vancomycin assayed nearly equaled the calculated amount of antibiotic per bead measured during bead construction. In conclusion, calcium phosphate-calcium sulfate composite beads, when combined with vancomycin, elute vancomycin in a gradual and sustained fashion for 22 days in vitro. LEVEL OF CLINICAL EVIDENCE: 2.

Impaired lower extremity wound healing secondary to sirolimus after kidney transplantation.

PURPOSE: Sirolimus is an immunosuppressive drug used as part of the drug regimen after kidney, liver, and heart transplantation. There have been numerous reports of transplant surgical wound healing complications secondary to sirolimus. The authors present a case of impaired wound healing in the lower extremity after kidney transplantation for a patient on sirolimus. This is one of the few reported cases that we are aware of that demonstrates the effects of sirolimus on wound healing at a nontransplant site. METHODS: A case highlighting aggressive limb-salvage modalities for a kidney transplant patient on sirolimus is presented. The subject was informed that data concerning the case would be submitted for publication. A brief review of the literature shows the wound healing problems previously associated with sirolimus. RESULTS: Despite all salvage techniques employed, including aggressive early debridement, forefoot offloading, IV antibiotics, negative pressure wound therapy, and hyperbaric oxygen therapy, the patient eventually went on to failure and a transtibial amputation. CONCLUSION: Physicians specializing in wound care and limb salvage must be aware of the effects of sirolimus on wound healing and should consider modifications to these patients' immunosuppressive regimens.

The in vitro elution characteristics of vancomycin and tobramycin from calcium sulfate beads.

The purpose of this study was to determine the elution characteristics of vancomycin and tobramycin when mixed with calcium sulfate to form antibiotic beads. Calcium sulfate was combined with vancomycin and tobramycin separately to form 2 types of antibiotic beads, which were packaged and labeled separately. The packaged calcium sulfate beads with vancomycin and tobramycin were then gas sterilized. The beads were placed in phosphate-buffered saline and kept at 36 degrees C for 6 weeks. Two separate series of assays were run simultaneously for both types of beads. In one assay, a bead containing vancomycin was placed in a fresh vial of phosphate buffered saline after each assay. The same was done with beads containing tobramycin. In the second series of assays, 9 vials of phosphate buffered saline each containing 1 vancomycin bead and 9 vials of phosphate buffered saline each containing 1 tobramycin bead was arranged. The phosphate-buffered saline was then assayed at predetermined times for both the vancomycin bead series and the tobramycin bead series. The amount of vancomycin and tobramycin assayed nearly equaled the calculated amount of antibiotic per bead measured before bead construction. Also, the elution of antibiotic from the calcium sulfate was complete within 72 hours. In conclusion, the construction and gas sterilization of calcium sulfate beads containing vancomycin and tobramycin does not destroy vancomycin and tobramycin. Also, the complete elution of available vancomycin and tobramycin in calcium sulfate beads occurs within 72 hours.

Is the radiographic appearance of the hallucal tarsometatarsal joint representative of its true anatomical structure?

The medial cuneiforms and first metatarsals were identified in 515 randomly selected specimens at the Hamman-Todd osteology collection in the Cleveland Museum of Natural History in Cleveland, Ohio, and the transverse plane angulation of the hallucal tarsometatarsal joint was determined by direct measurement of the selected bones. Medial cuneiforms were subsequently separated into three categories corresponding to the amount of measured obliquity. The first tarsometatarsal joint was reassembled, and the paired medial cuneiforms and first metatarsals were radiographed at different declination angles in inverted, everted, and rectus positions. Radiographic evaluation revealed discordance between the appearance of atavism and true atavism in the cuneiform. Specifically, it was determined that the position of the hallucal tarsometatarsal joint significantly influenced the appearance of atavism in the cuneiform. It is concluded that the position of the first ray in an anteroposterior radiograph can produce the appearance of an increased obliquity angle of the medial cuneiform, resulting in an inaccurate representation of the hallucal tarsometatarsal joint. (J Am Podiatr Med Assoc 92(9): 491-498, 2002)