Current treatments for methicillin-resistant Staphylococcus aureus (MRSA) infections require intravenously delivered vancomycin; however, systemically delivered vancomycin has its problems. To determine the feasibility and safety of locally delivering vancomycin hydrochloride (~25 mg/Kg) to the medullary canal of long bones, we conducted a pharmacokinetics study using a rat tibia model. We found that administering the vancomycin intraosseously resulted in very low concentrations of vancomycin in the blood plasma and the muscle surrounding the tibia, reducing the risk for systemic toxicity, which is often seen with traditional intravenous administration of vancomycin. Additionally, we were able to inhibit the development of osteomyelitis in the tibia if the treatment was administered locally at the same time as a bacterial inoculum (i.e., Log10 7.82 CFU/mL or 6.62x107 CFU/mL), when compared to an untreated group. These findings suggest that local intramedullary vancomycin delivery can achieve sufficiently high local concentrations to prevent development of osteomyelitis while minimizing systemic toxicity.
The Purkinje system (PS) and the His bundle have been recently implicated as an important driver of the rapid activation rate after 1-2 minutes of ventricular fibrillation (VF). It is unknown whether activations during VF propagate through the His-Purkinje system to other portions of the the working myocardium (WM). Little is known about restitution characteristic differences between the His bundle and working myocardium at short cycle lengths. In this study, rabbit hearts (n=9) were isolated, Langendorff- perfused, and electromechanically uncoupled with blebbistatin (10 μM). Pacing pulses were delivered directly to the His bundle. By using standard glass microelectrodes, action potentials duration (APD) from the His bundle and WM were obtained simultaneously over a wide range of stimulation cycle lengths (CL). The global F-test indicated that the two restitution curves of the His bundle and the WM are statistically significantly different (P<0.05). Also, the APD of the His bundle was significantly shorter than that of WM throughout the whole pacing course (P<0.001). The CL at which alternans developed in the His bundle vs. the WM were shorter for the His bundle (134.2±13.1ms vs. 148.3±13.3ms, P<0.01) and 2:1 block developed at a shorter CL in the His bundle than in WM (130.0±10.0 vs. 145.6±14.2ms, P<0.01). The His bundle APD was significantly shorter than that of WM under both slow and rapid pacing rates, which suggest that there may be an excitable gap during VF and that the His bundle may conduct wavefronts from one bundle branch to the other at short cycle lengths and during VF.
The data set includes individual images of mouse cochleae, both scanning electron micrographs and fluorescent micrographs, used to generate aggregated data described in Ali A. Almishaal; Phayvanh P. Sjogren; Pranav D. Mathur; Elaine Hillas;Taelor Johnson; Melissa S. Price; Travis Haller; Jun Yang; Namakkal S. Rajasekaran; Matthew A. Firpo; Albert H. Park (2018) "Reactive Oxygen Species and Hearing Loss in Murine CMV Labyrinthitis".
Background. Common cold viruses create significant health and financial burdens, and understanding key loci of transmission would help focus control strategies. This study (1) examines factors that influence when individuals transition from a negative to positive test (acquisition) or a positive to negative test (loss) of rhinovirus (HRV) and other respiratory tract viruses in 26 households followed weekly for one year, (2) investigates evidence for intrahousehold and interhousehold transmission and the characteristics of individuals implicated in transmission, and (3) builds data-based simulation models to identify factors that most strongly affect patterns of prevalence. Methods. We detected HRV, coronavirus, paramyxovirus, influenza and bocavirus with the FilmArray polymerase chain reaction (PCR) platform (BioFire Diagnostics, LLC). We used logistic regression to find covariates affecting acquisition or loss of HRV including demographic characteristics of individuals, their household, their current infection status, and prevalence within their household and across the population. We apply generalized linear mixed models to test robustness of results. Results. Acquisition of HRV was less probable in older individuals and those infected with a coronavirus, and higher with a higher proportion of other household members infected. Loss of HRV is reduced with a higher proportion of other household members infected. Within households, only children and symptomatic individuals show evidence for transmission, while between households only a higher number of infected older children (ages 5-19) increases the probability of acquisition. Coronaviruses, paramyxoviruses and bocavirus also show evidence of intrahousehold transmission. Simulations show that age-dependent susceptibility and transmission have the largest effects on mean HRV prevalence. Conclusions. Children are most likely to acquire and most likely to transmit HRV both within and between households, with infectiousness concentrated in symptomatic children. Simulations predict that the spread of HRV and other respiratory tract viruses can be reduced but not eliminated by practices within the home.