Sustained delivery of siRNA poly- and lipopolyplexes from porous macromer-crosslinked gelatin gels.

RNA interference (RNAi) is a promising technique to treat severe diseases on a pre-protein level. We and others postulate that the release of nanoparticle-complexed small interfering RNA (siRNA) from implanted biomaterials could provide structural support for tissue repair, combined with local siRNA transfection of invading and regenerating cells. In this study, we systematically investigated cross-linked gelatin based hydrogel formulations (cGEL) as degradable controlled release matrices for siRNA. Aiming at the definition of correlations between cGEL composition, siRNA nanoparticle formulation, release kinetics of complexed siRNA and transfection efficiency, we combined five different cGEL formulations and three transfection systems, i.e. polyplexes with polyethyleneimine (PEI), PEI in combination with liposomes (lipopolyplexes) and polyplexes based on tyrosin-modified PEI (P10Y). It was found that the distribution of these poly-/lipopolyplexes, when applied onto the negatively charged hydrogels, was strongly dependent on their zeta potential. Furthermore, siRNA release from the hydrogel was a multifactorial process, as diffusion, hydrogel degradation and nanoparticle decomplexation overlapped over time. This resulted in a prolonged release of siRNA for up to 21days. In the case of PEI complexes and lipopolyplexes, release kinetics depended on the cGEL formulation. In contrast, when employing P10Y polyplexes, an initial burst release was observed with no further release thereafter. Silencing activity was determined using constitutively luciferase-expressing SKOV-3-Luc reporter cells. Surface and bulk porosity in hydrogels was introduced by addition of soluble polyethylene glycol during fabrication, leading to improved knockdown. The rapid onset of knockdown efficacy will also provide the basis for the determination of long-term effects.

Genetic aspects of familial multiple myeloma.

To elucidate the role of genetics in familial multiple myeloma, two sisters having plasma cell dyscrasia were studied. The women were 58 and 56 years old, and the diagnoses were made 22 months apart. Specific antisera for patient 1's lambda light chains produced in rabbits had no cross-reactivity with her sister's lambda light chains. Karyotypic analysis by G.T.G. banding revealed abnormalities in both patients, but no common abnormalities. HLA typing disclosed identical tissue types (AW24, A26, B13, BW55). An immunologic epidemiologic study performed on 26 family members, encompassing four generations, disclosed no additional cases of paraproteinemia.

Bite wounds to the upper extremity.

The complications secondary to mismanaged or neglected bite wounds to the upper extremity can be devastating to upper extremity functioning. An organized approach to treatment can prevent infection and permanent disability.

Minimal surgical debridement for the treatment of chemotherapeutic agent-induced skin extravasations.

A rat model was employed to determine the efficacy of early minimal debridement in decreasing the size of chemotherapeutic agent-induced skin ulcers. After receiving bilateral flank injections of doxorubicin in a concentration comparable to that received by humans, the right injection site underwent minimal debridement 1, 24, or 72 hours after the injection. The left side of each animal was not operated upon and served as a control. Three subgroups of the 1-, 24-, and 72-hour debridement groups were treated as previously described, except that any residual necrotic tissue was debrided 1 week after the original debridement. All minimal debridement and redebridement groups produced significant decreases in ulcer size compared to controls. Comparing minimal debridement and redebridement groups to controls, it was found that surgery produced reductions in the number of persistent ulcers in all groups. Minimal debridement followed by redebridement was significantly more effective than minimal debridement alone in decreasing ulcer size acutely. One case is presented in which an extravasation of dactinomycin was treated by early minimal debridement. The patient had an uncomplicated postoperative course, and at follow-up 21 months after surgery had excellent functional and cosmetic results. Based upon animal studies and human experience, early surgical debridement appears to be a promising new method for the treatment of clinically significant vesicant extravasations in humans.

Coronal dorsal hamate fractures.

Four patients with a rare injury, coronal fracture of the dorsal hamate with associated dorsal subluxations of the ring and small metacarpal bases were treated with open reduction and internal fixation with the use of cortical mini-lag screws and Kirschner wires. Average follow-up was 12 months (range, 6 to 19 months). Subjective patient assessment and objective strength, range of motion measurements, and radiographs demonstrated excellent overall results. Open reduction and internal fixation is recommended for the treatment of this unusual fracture-subluxation.

Extravasations of radiographic contrast material in the upper extremity.

Five significant extravasations of radiographic contrast material in the upper extremity were treated with early surgical drainage in an attempt to prevent extensive skin necrosis. Four of the five patients underwent operation within 6 hours of the extravasations, and all of these patients had excellent functional and cosmetic results without any evidence of skin necrosis. One patient who had a poor result did not undergo operation until 20 hours after a severe extravasation to the dorsum of the right hand. Most small-volume, less-extensive extravasations can be satisfactorily managed conservatively. Our clinical experience indicates that large subcutaneous extravasations of radiographic contrast material (volume more than 20 ml) should be surgically drained within 6 hours to prevent extensive damage to tissue.

Extravasation injuries in the upper extremity.

Fourteen patients with intravenous extravasations of chemotherapeutic medications, radiographic contrast agents, vasopressors, fluorescein, or albumin/potassium phosphate were evaluated with regard to function and cosmesis. The average follow-up period was 8.4 months (range, one-24 months). Five patients initially were managed conservatively and, after demarcation of the necrotic area, had surgical procedures for skin coverage. Four of these patients had poor functional and cosmetic results. The remaining patient had an excellent final result. Because of the generally poor results observed in the aforementioned patients, a program of early recognition and surgical intervention in selected extravasation cases was instituted. Following this change, eight of nine patients had good or excellent results. Early surgical involvement in the evaluation of extravasations, with and early surgical drainage and irrigation in selected severe cases, appears to improve the outcome of these iatrogenic injuries.

Treatment methods for extravasations of chemotherapeutic agents: a comparative study.

A rat model was used to compare early surgical intervention with injectable and topical antidotes with regard to their effectiveness in preventing cutaneous ulcers that were caused by intradermal injections of vesicant chemotherapeutic agents. The (animals) rats received bilateral flank injections of doxorubicin, vincristine, actinomycin D, mitomycin C, or carmustine (BCNU) in concentrations that were comparable to concentrations used for human patients; after the injections they underwent debridement at various intervals or received immediate applications of selected antidotes. Many "antidotes" which were frequently used, were not effective in limiting the size of the ulcer and in producing rapid healing of ulcers that were caused by experimental vesicant extravasations. Early surgical debridement was the most effective method of decreasing vesicant ulcer size and facilitating rapid ulcer healing of all the interventions tested.