Prevalence and patterns of foot injuries following motorcycle trauma.

OBJECTIVES: To determine the prevalence and patterns of foot injuries following motorcycle trauma. DESIGN: Prospective. SETTING: Yorkshire Region Trauma Units (Level 1 trauma centers with trauma research). PATIENTS: Individuals injured in motorcycle road traffic accidents between January 1993 and December 1999. OUTCOME MEASUREMENTS: Patient demographics, protective devices (helmet) use, Injury Severity Score (ISS), Glasgow Coma Scale (GCS), clinical details, therapeutic interventions, resuscitation requirements, duration of hospital stay, mortality, and type of foot injuries sustained. RESULTS: The parent population of 1239 contained 53 (4.3%) foot-injured motorcyclists (49 men) with a mean age of 31.7 years (range 18-79 years). Fifty-two were drivers and one was a rear-seat passenger. Mean ISS was 6.9 (range 4-33), significantly lower than the parent population mean of 34.98 (range 9-75) (P = 0.001). Mean GCS was 14.7 (range 13-15). The motorcyclists' injuries included 26 metatarsal fractures (49.1%), 14 talar fractures (26.4%), 7 os calcis fractures (13.2%), and 6 toe fractures (11.3%). Associated foot injuries included three partial foot amputations, four Lisfranc dislocations, three cases of foot compartment syndrome (two crush injuries with no fracture, one open fourth metatarsal fracture with associated Lisfranc dislocation). Forty-six motorcyclists had more than one foot injury. Associated injuries included 22 ankle fractures (41.5%), 15 tibial fractures (28.3%), 6 femoral fractures (11.3%), 5 pelvic ring fractures (9.4%), 23 upper limb injuries (43.4%), and 3 cases of chest trauma (5.7%). No one sustained abdominal trauma or head injury compared with the parent population. All patients required operative stabilization of foot fractures, including their associated injuries. Mean hospital stay was 10.9 days (range 1-35 days). In the parent population, there were 71 deaths (6.0%), whereas there was only 1 death (1.9%) in the foot-injured group (with fractures including open book pelvic, T6-8, unilateral open femur, tibial, ankle, and metatarsal) with an ISS 33, who died of multiorgan dysfunction syndrome. At final follow-up, all patients underwent radiologic and clinical assessment of foot injuries. Forty-three patients returned to their previous occupation and level of mobility. Ten of the more significantly injured patients had to modify their occupation from manual to sedentary-type jobs due to their foot injuries. We noted a pattern of complex ipsilateral foot and limb injury in nine patients, which we postulate was due to the actual mechanism of contact with the road surface. CONCLUSION: Motorcycle accidents continue to be a source of severe injury, especially to the foot. The most common foot injury is a metatarsal fracture; however, there must be a high index of suspicion for associated injuries. Although these injuries are associated with a low mortality rate, they require prompt assessment and treatment to limit long-term morbidity and disability. The difference in foot injury pattern and mortality between the parent population and our series, among other factors, potentially may be influenced by the actual mechanism of contact with the road surface and the modifying action of the foot during the accident.

Novel solution-phase immunoassays for molecular analysis of tumor markers.

at 3 x 10(9) M(-1) and a step-wise binding process with PSA-free MAB. Thus, this solution-phase quantitative ECL immunoassay allowed measurement of the affinity of serum PSAs with their MABs and screening of PSAs based upon their affinity to MABs. Unlike other immunoassays, this immunoassay demonstrated one-step rapid analysis while simultaneously eliminating immobilization, separation and washing steps and detected PSA at a level of 1.7 pg mL(-1), which is 1000-fold more sensitive than current PSA immunoassays. Furthermore, single-molecule (SM) phosphorescence microscopy was developed to detect single serum PSA-free and PSA-complex molecules in solution with no use of antibody showing that PSA-free molecules diffused faster than PSA-complex molecules in solution. This finding is consistent with ECL measurements and implies the possibility of screening individual analytes in a complex mixture using their distinct SM diffusion distance. This is the first report describing the detection of single protein molecules labeled with a metal-complex using phosphorescence microscopy and also the screening of serum tumor markers using ECL and SM phosphorescence solution-phase assays.

Effects of sonodynamic and photodynamic treatment on cellular thiol levels.

Exposure of murine leukemia L1210 cells to ultrasound in vitro resulted in cell fragmentation; cells which survived this treatment were 100% viable and showed a transient decrease in intracellular thiol pools (expressed as glutathione equivalents). Depletion of thiol pools became progressively greater with increasing exposure of cells to ultrasound; this was not associated with leakage of thiols into the medium. Biochemically elevating glutathione levels or sonication in the presence of the anti-oxidant trolox offered only a minor degree of protection against sonotoxicity. Photodynamic therapy also resulted in depletion of intracellular thiol levels, and loss of cell viability. In the presence of trolox, both effects were reversed, although elevation of intracellular thiol levels did not protect cell from phototoxicity.

Modes of photodynamic vs. sonodynamic cytotoxicity.

We compared effects of ultrasound-induced vs. photodynamic cytotoxicity in cell culture. The photodynamic effects mediated by mesoporphyrin caused a delayed toxic reaction, the presence of a "shoulder" on the dose-response curve, indicating the capacity for limited repair of photodamage. In contrast, ultrasound-induced loss of viability resulted from rapid cell destruction and was proportional to the time of sonication. Photodynamic damage to cells before exposure to ultrasound potentiated cell breakage but did not affect the clonogenicity of the surviving cell population. Photodamage after exposure to ultrasound decreased the viability of cells which had survived ultrasonic treatment.

Dimethylformamide as an enhancer of cavitation-induced cell lysis in vitro.

Polar solvents, including dimethylformamide (DMF), have been investigated as anticancer drugs, but their potential usefulness is constrained by hepatotoxic side effects. The ability to enhance drug cytotoxicity with ultrasound would be valuable in creating locally intense chemotherapy while minimizing effects peripheral to the treatment site. The effects of continuous wave ultrasound (US) (985 kHz; 0.5-2.5 W/cm2) were evaluated on cultured HL-60 human promyelocytic leukemia cells alone and with a noncytotoxic DMF dose (0.11 M). The cells were insonified in a configuration that created no cell lysis without the introduction of albumin-stabilized microbubbles into the exposure chamber. When microbubbles were introduced, US with bubbles induced cell lysis, and the presence of DMF significantly increased the lysis induced by ultrasound with bubbles. The necessary presence of microbubbles for the DMF-US synergism to occur suggests that a likely mechanism is acoustic cavitation, initiated by the presence of microbubbles as nuclei. Detection of subharmonics confirmed the presence of cavitation, and cell lysis was well correlated with the subharmonic amplitude. The results show that albumin-stabilized microbubbles, similar to those currently used as US contrast agents, may provide a significant source of nuclei and improve prospects for cancer therapy using acoustic cavitation. The evidence presented supports the hypothesis that cell damage is due to a sonochemical rather than to a sonomechanical process.

Porphyrin-induced enhancement of ultrasound cytotoxicity.

We examined the effect of ultrasound on the murine leukaemia L1210 cell line in culture, in the presence of porphyrins varying widely in their capacity to sensitize cells to light. These porphyrins enhanced ultrasound-induced cell damage in vitro only when present in the incubation medium. When cells containing intracellular porphyrins were exposed to ultrasound, cell viability was not altered. Moreover, there was no correlation between the efficacy of a given porphyrin for light- versus ultrasound-induced cytotoxicity. Loss of viability was associated with inhibition of amino acid transport and cell fragmentation, suggesting disruption of the integrity of the cell membrane. Ultrasound-induced cell damage occurred only in the presence of cavitation nuclei.