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Propionibacterium sp. is commonly isolated in association with orthopedic implants, either as a pathogen or a colonizer. Microbial characteristics that indicate whether the isolated species is a likely cause of orthopedic implant infection versus a colonizing agent would be clinically useful. We performed a prospective trial to determine the species of Propionibacterium and the phylotype (IA, IB, II, III) of Propionibacterium acnes isolated from the surface of removed orthopedic implants, and we correlated these findings with the presence or absence of infection. P. acnes represented 61 of 62 isolates. P. acnes type I was more commonly isolated than was type II (62% versus 38%, respectively), whether associated with infection or not. P. acnes type III was not detected. There was no clear association between types I and II P. acnes and infection or colonization of failed orthopedic implants (P = 0.75), however type IB strains were more frequently isolated than type IA from infected prosthese.

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Cochlear implants are devices, which are implanted into the cochlea to aid hearing via stimulation of the cochlear nerve. For this study, we were interested in understanding the age-related changes in the impedances of the electrodes implanted with a cochlear implant system. The impedances of the electrodes reflect the integrity of the implanted system in the inner ear, and the efficiency of transmission of information from the externally worn device to the implanted system. Thus, monitoring cochlear impedances is important for the patient's rehabilitation. Our hypothesis was that cochlear implant impedances would decrease as an effect of age. Current systems record the impedances via a telemetry system when the patient’s cochlear implant is connected to the programming software. This data is saved within the system and can be retrieved and de-identified within the software. In our investigation, we collected the de-identified impedance data from this system to understand the effects of age. This data was collected from the ETSU Audiology Clinic at the Nave Center. The de-identified data was reviewed and sorted between 3 different age brackets. Data was averaged and compared between age brackets and electrodes. Overall, we found in this study that there are no significant differences between age brackets when comparing cochlear implant impedances across the different electrodes. The slight differences between impedances across electrodes and age brackets could be due to many contributing factors, however, the differences were not considered statistically significant. This study could indicate future directions for further research including, comparing impedance differences between male and female subjects, longitudinal case studies, and comparing across implant manufacturers and device type.

The diversity of network disruptions that occur in patients with neuropsychiatric disorders creates a strong demand for personalized medicine. Such approaches often take the form of implantable bioelectronic devices that are capable of monitoring pathophysiological activity for identifying biomarkers to allow for local and responsive delivery of intervention. They are also required to transmit this data outside of the body for evaluation of the treatment’s efficacy. However, the ability to perform these demanding electronic functions in the complex physiological environment with minimum disruption to the biological tissue remains a big challenge. An optimal fully implantable bioelectronic device would require each component from the front-end to the data transmission to be conformable and biocompatible. For this reason, organic material-based conformable electronics are ideal candidates for components of bioelectronic circuits due to their inherent flexibility, and soft nature. In this work, first an organic mixed-conducting particulate composite material (MCP) able to form functional electronic components and non-invasively acquire high–spatiotemporal resolution electrophysiological signals by directly interfacing human skin is presented. Secondly, we introduce organic electrochemical internal ion-gated transistors (IGTs) as a high-density, high-amplification sensing component as well as a low leakage, high-speed processing unit. Finally, a novel wireless, battery-free strategy for electrophysiological signal acquisition, processing, and transmission that employs IGTs and an ionic communication circuit (IC) is introduced. We show that the wirelessly-powered IGTs are able to acquire and modulate neurophysiological data in-vivo and transmit them transdermally, eliminating the need for any hard Si-based electronics in the implant.

AIM: To measure marginal bone loss around endosseous dental implants at 2nd stage abutment surgery and retrospectively evaluate the association of pre-surgical variables with bone findings. MATERIALS AND METHODS: Two implant systems were included in the study design. Straumann Bone Level Tapered SLActive and Nobel Biocare Replace Conical Connection. Implants were placed by the same resident from the Periodontics department. Clinical measurements of bone level were recorded at the time of placement and then again at 2nd stage surgery at four different points (mesial, lingual, buccal, distal). RESULTS: Five implants were evaluated in the study. Bone loss averages ranged from 0-1.0mm. Nobel implants had an average loss of .75mm and Straumann implants had an average loss of .67mm. CONCLUSION: Many variables contribute to marginal bone loss around endosseous dental implants at 2nd stage abutment surgery. The current research was designed to understand the relationship between these variables and early marginal bone loss. All implant samples included here were defined as control because of ≤1.0mm bone loss per IRB protocol.

Since bone tissues grow in intimate contact with implant surfaces in vivo, there is a need to investigate how bone cells respond to mechanical loads adjacent to implants under well characterized loading conditions that stimulate the bone-implant surface. Thus, the objective of this study was to demonstrate an effective means for applying known, uniform, cyclic strain to cells growing on implant materials in vitro. A cell culture strain plate device was developed based on the application of the four-point bending principle. The device uses a small electric motor to drive belts attached to shafts which turn a set of cams. The cams are attached to pins which connect to a titanium plate which rests over arched supports. When deflected and depending on which set of cams are used, strains generated range from around 200 to 1000 ìstrain. UMR-106 osteoblast-like cells were cultured on the titanium plate, and the plate was deflected at three strain magnitudes at 1.5 Hz for durations of 4 and 24 hours. Strain gages recorded average maximum strain levels of 182 ± 3, 366 ± 9, and 984 ± 7µstrain. The strain device, with attached cells, was tested in an amiable bioenvironment. Results from strain gages indicated a uniform strain field existed within the center region of the plate and culture area. Cells in the test plates stained viable, exhibited similar morphology to controls, and were assayed for alkaline phosphatase (ALP) activity, total protein production, and calcium deposition. Results also indicated that stretched cells exhibited increases in proliferation, as well as changes in ALP activity vs. unstrained controls. Thus, the device was successful in distinguishing differences in cell response to mechanical perturbations and may be used to investigate how cells respond to strains at implant-bone interfaces.

Bone and bone cells have been shown to respond to mechanical forces placed upon them. Particularly, strain plays an important role in osteogenic differentiation of marrow cells around artificial implants in bone. These strains, depending on their magnitude, duration, and repetition, can alter the proliferation and matrix synthesis of osteoblasts. To test how strain parameters influence osteoblast behavior, a four-point bending apparatus was used to impose cyclic strain on osteogenic stem cells isolated from rats and seeded on titanium plates. Cells were stimulated at 1 Hz for 15 minutes daily and compared to an unstrained control. Stimulation occurred at two magnitudes: 400 and 1000 micro-strain, and three levels of repetition: one, three, and five consecutive days. DNA, protein, alkaline phosphatase, and calcium levels were measured to determine the proliferation and matrix synthesis activity of the cells. No statistically significant effect was found for the tested parameters under these conditions.

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No description available.