Quantitative Measurements of Protein Volume and Concentration using Hydrogel-Backed Nanopores.

Accurate identification and quantification of proteins in solution using nanopores is technically challenging in part because of the large fraction of missed translocation events due to short event times and limitations of conventional current amplifiers. Previously, we have shown that a nanopore interfaced with a poly(ethylene glycol)-dimethacrylate hydrogel with an average mesh size of 3.1 nm significantly enhances the protein residence time within the pore, reducing the number of missed events. We used hydrogel-backed nanopores to sense unlabeled proteins as small as 5.5 kDa in size and 10 fM in concentration. We show that the frequency of protein translocation events linearly scales with bulk concentration over a wide range of concentrations and that unknown protein concentrations can be determined from an interpolation of the frequency-concentration curve with less than 10% error. Further, we show an iterative method to determine a protein volume accurately from measurement data for proteins with a diameter comparable to a nanopore diameter. Our measurements and analysis also suggest several competing mechanisms for the detection enhancement enabled by the presence of the hydrogel.

Equestrian trauma: injury patterns vary among age groups.

Patients with equestrian injuries were identified in the trauma registry from 2004 to 2007. We a priori divided patients into three groups: 0 to 18 years, 19 to 49 years, and 50 years old or older. There were 284 patients identified with equestrian-related trauma. Injury Severity Score for the three major age categories 0 to 18 years, 19 to 49 years, and 50 years or older, were 3.47, 5.09, and 6.27, respectively. The most common body region injured among all patients was the head (26.1%). The most common injuries by age group were: 0 to 18 years, upper extremity fractures; 19 to 49 year olds, concussions; and 50 years or older, rib fractures. Significant differences were observed among the three age groups in terms of percent of patients with rib fractures: percent of patients with rib fractures was 2, 8, and 22 per cent in age groups 0 to 18, 19 to 49, and 50 years or older, respectively. We found different patterns of injuries associated with equestrian accidents by age. Head injuries were commonly seen among participants in equestrian activities and helmet use should be promoted to minimize the severity of closed head injuries. Injury patterns also seem to vary among the various age groups that ride horses. This information could be used to better target injury prevention efforts among these patients.

Standard computed tomography of the chest, abdomen, and pelvis is sensitive and cost-effective for the detection of fractures of the shoulder girdle.

Computed tomography of the chest, abdomen, and pelvis (CTCAP) has become the mainstay of diagnosis in stable blunt trauma patients. The purpose of this study was to investigate whether standard CTCAP has adequate sensitivity to identify fractures of the scapula, clavicle, and humeral head to replace routine radiographs of the shoulder. A retrospective chart review was carried out from January 1, 2004, to December 31, 2007, at Morristown Memorial Hospital. Inclusion criteria were all shoulder fracture patients in our trauma registry who underwent both a CTCAP and plain radiographs of the injured shoulder. Data were collected for patient age, sex, Injury Severity Score, mechanism of injury, and fracture location. Sensitivity was calculated for each diagnostic modality as well as hospital costs and radiation dose of plain radiographs. A total of 374 charts were reviewed and 98 patients were included in the study with a total of 117 fractures. The sensitivity of trauma CTCAP for scapula fractures was 100 per cent, clavicle fractures 98 per cent, and humeral head fractures 100 per cent. The sensitivity of the shoulder series for scapula fractures was 60 per cent, clavicle fractures 85 per cent, and humeral head fractures 100 per cent. The plain radiographs added $298 in hospital charges and 0.191 mSv of radiation per patient. CTCAP is a sensitive tool for identifying fractures in the shoulder girdle. Therefore, CTCAP can replace the routine radiographs of the shoulder resulting in less total radiation exposure of the trauma patients. This also would lead to lower healthcare cost and better diagnostic workflow.

Does patient age and height of fall alone require trauma team activation?

Our American College of Surgeons Level I trauma center uses physiological data and injury patterns to identify fall patients at risk. We hypothesized that height of fall and patient age impacted injury severity and analyzed if they were significant predictors of the need for trauma team activation. Charts were reviewed from July 1, 2004, to June 30, 2007, for age; sex; Injury Severity Score (ISS); height of fall and admission to the intensive care unit, operating room, stepdown unit, floor; or death. Exclusion criteria were physiological, neurologic, or airway compromise and penetrating neck or torso injuries. ISS was used as a positive control. A total of 1865 fall patients were treated during the period of data collection, and 1348 patients were eliminated by exclusion criteria, leaving 517 patients for study. Although patient age did not correlate with the need for trauma team activation, there was a statistically significant association between age and admission to the hospital from the emergency room (P < 0.05; area under curve [AUC] = 0.713; 95% confidence interval [CI], 0.656 to 0.770). Similarly, although the height of fall alone did not have a significant predictive value for the need of trauma team activation, there was a clear association of the height of fall with hospital admission (AUC = 0.589; 95% CI, 0.519 to 0.658). Patient age and height of fall alone are not criteria for trauma team activation in the absence of physiological, neurologic, or airway compromise.

Spinal clearance in the difficult trauma patient: a role for screening MRI of the spine.

Identifying spinal injuries in trauma patients with altered mental status can be difficult. CT scanning and clinical examination are the basis of our spinal clearance, but screening "trauma protocol" spinal MRI is used to exclude occult injuries. We sought to evaluate the sensitivity of CT scanning for spinal injuries compared with our MRI protocol. Ninety-seven patients underwent MRI cervical spine trauma protocol during 2004. Twenty-nine patients were obtunded, 29 had neurologic symptoms, and 39 had spine pain. MRI confirmed the initial CT findings without new injuries in 83 cases. MRI reclassified fractures as degenerative changes in 12 cases. In 2 cases, the MRI identified new injuries: one a stable partial ligament tear, the second a T7 Chance fracture with ligamental disruption requiring operative fixation. There was no morbidity or mortality documented in obtaining the MRI studies. Overall negative predictive value of CT scanning of the spine was 98 per cent, the positive predictive value was 78 per cent, and the sensitivity and specificity was 94 per cent and 91 per cent, respectively. CT scanning of the cervical and axial spine is sensitive for spinal trauma but not specific. MRI trauma protocol should be reserved for cases when initial CT scanning is suggestive of traumatic injury.