In vivo confocal imaging of epidermal cell migration and dermal changes post nonablative fractional resurfacing: study of the wound healing process with corroborated histopathologic evidence.

In vivo wound healing response post nonablative fractional laser treatment is evaluated. Seven healthy subjects receive treatments with a Fraxel re:store laser system on the forearm with pulse energies ranging from 10 to 70 mJ. The treatment sites are imaged at 1-h increments up to 40 h using confocal microscope z-stacks using 10-mum-depth spacing. At least five individual microscopic treatment zones are imaged per subject, time point, and treatment energy. Images are analyzed for tissue structure and morphology to classify each lesion as healed or not healed, depending on epidermal re-epithelialization at each time point and treatment energy. Probit analysis is used to statistically determine the ED(50) and ED(84) probabilities for a positive dose response (healed lesion) as a function of treatment energy. Confocal observations reveal epidermal keratinocyte migration patterns confirmed with histological analysis using hematoxylin and eosin (HE) and lactate dehydrogenase (LDH) staining at 10 mJ at 0, 7, 16, and 24-h post-treatment. Results indicate that more time is required to conclude re-epithelialization with larger lesion sizes (all less than 500 mum) corresponding to higher treatment energies. For the entire pulse energy range tested, epidermal re-epithelialization concludes between 10 to 22-h post-treatment for ED(50) and 13 to 28 h for ED(84).

Fractional deep dermal ablation induces tissue tightening.

BACKGROUND AND OBJECTIVE: Due to the significant risk profile associated with traditional ablative resurfacing, a safer and less invasive treatment approach known as fractional deep dermal ablation (FDDA) was recently developed. We report the results of the first clinical investigation of this modality for treatment of photodamaged skin. STUDY DESIGN/MATERIALS AND METHODS: Twenty-four subjects received treatments on the inner forearm with a prototype fractional CO(2) laser device (Reliant Technologies Inc., Mountain View, CA) at settings of 5-40 mJ/MTZ and 400 MTZ/cm(2). Clinical and histological effects were assessed by study investigators 1 week, 1 month, and 3 months following treatment. Thirty subjects were then enrolled in a multi-center study for treatment of photodamage using the same device. Subjects received 1-2 treatments on the face and neck, with energies ranging from 10 to 40 mJ/MTZ and densities ranging from 400 to 1,200 MTZ/cm(2). Study investigators assessed severity of post-treatment responses during follow-up visits 48 hours, 1 week, 1 month, and 3 months following treatment. Using a standard quartile improvement scale (0-4), subjects and investigators assessed improvement in rhytides, pigmentation, texture, laxity and overall appearance 1 and 3 months post-treatment. RESULTS: Clinical and histologic results demonstrated that fractional delivery of a 10,600 nm CO(2) laser source offers an improved safety profile with respect to traditional ablative resurfacing, while still effectively resurfacing epidermal and dermal tissue. Forearm and facial treatments were well-tolerated with no serious adverse events observed. Eighty-three percent of subjects exhibited moderate or better overall improvement (50-100%), according to study investigator quartile scoring. CONCLUSIONS: FDDA treatment is a safe and promising new approach for resurfacing of epidermal and deep dermal tissue targets.

Clinical feasibility of a wearable, conformable sensor patch to monitor motor symptoms in Parkinson's disease.

INTRODUCTION: Clinical assessment of motor symptoms in Parkinson's disease (PD) is subjective and may not reflect patient real-world experience. This two-part pilot study evaluated the accuracy of the NIMBLE wearable biosensor patch (containing an accelerometer and electromyography sensor) to record body movements in clinic and home environments versus clinical measurement of motor symptoms. METHODS: Patients (Hoehn & Yahr 2-3) had motor symptom fluctuations and were on a stable levodopa dose. Part 1 investigated different sensor body locations (six patients). In Part 2, 21 patients wore four sensors (chest, and most affected side of shin, forearm and back-of-hand) during a 2-day clinic- and 1-day home-based evaluation. Patients underwent Unified Parkinson's Disease Rating Scale assessments on days 1-2, and performed pre-defined motor activities at home on day 3. An algorithm estimated motor-symptom severity (predicted scores) using patch data (in-clinic); this was compared with in-clinic motor symptom assessments (observed scores). RESULTS: The overall correlation coefficient between in-clinic observed and sensor algorithm-predicted scores was 0.471 (p = 0.031). Predicted and observed scores were identical 45% of the time, with a predicted score within a ±1 range 91% of the time. Exact accuracy for each activity varied, ranging from 32% (pronation/supination) to 67% (rest-tremor-amplitude). Patients rated the patch easy-to-use and as providing valuable data for managing PD symptoms. Overall patch-adhesion success was 97.2%. The patch was safe and generally well tolerated. CONCLUSIONS: This study showed a correlation between sensor algorithm-predicted and clinician-observed motor-symptom scores. Algorithm refinement using patient populations with greater symptom-severity range may potentially improve the correlation.

Using Patient Feedback to Optimize the Design of a Certolizumab Pegol Electromechanical Self-Injection Device: Insights from Human Factors Studies.

INTRODUCTION: We incorporated patient feedback from human factors studies (HFS) in the patient-centric design and validation of ava®, an electromechanical device (e-Device) for self-injecting the anti-tumor necrosis factor certolizumab pegol (CZP). METHODS: Healthcare professionals, caregivers, healthy volunteers, and patients with rheumatoid arthritis, psoriatic arthritis, ankylosing spondylitis, or Crohn's disease participated in 11 formative HFS to optimize the e-Device design through intended user feedback; nine studies involved simulated injections. Formative participant questionnaire feedback was collected following e-Device prototype handling. Validation HFS (one EU study and one US study) assessed the safe and effective setup and use of the e-Device using 22 predefined critical tasks. Task outcomes were categorized as "failures" if participants did not succeed within three attempts. RESULTS: Two hundred eighty-three participants entered formative (163) and validation (120) HFS; 260 participants performed one or more simulated e-Device self-injections. Design changes following formative HFS included alterations to buttons and the graphical user interface screen. All validation HFS participants completed critical tasks necessary for CZP dose delivery, with minimal critical task failures (12 of 572 critical tasks, 2.1%, in the EU study, and 2 of 5310 critical tasks, less than 0.1%, in the US study). CONCLUSION: CZP e-Device development was guided by intended user feedback through HFS, ensuring the final design addressed patients' needs. In both validation studies, participants successfully performed all critical tasks, demonstrating safe and effective e-Device self-injections. FUNDING: UCB Pharma. Plain language summary available on the journal website.

Dehydration mechanism of optical clearing in tissue.

Previous studies identified various mechanisms of light scattering reduction in tissue induced by chemical agents. Our results suggest that dehydration is an important mechanism of optical clearing in collagenous and cellular tissue. Photographic and optical coherence tomography images indicate that air-immersed skin and tendon specimens become similarly transparent to glycerol-immersed specimens. Transmission electron microscopy images reveal that dehydration causes individual scattering particles such as collagen fibrils and organelles to become more densely packed, but does not significantly alter size. A heuristic particle-interaction model predicts that the scattering particle volume fraction increase can contribute substantially to optical clearing in collagenous and cellular tissue.

Thermal model for optimization of vascular laser tissue soldering.

Laser tissue soldering (LTS) is a promising technique for tissue fusion based on a heat-denaturation process of proteins. Thermal damage of the fused tissue during the laser procedure has always been an important and challenging problem. Particularly in LTS of arterial blood vessels strong heating of the endothelium should be avoided to minimize the risk of thrombosis. A precise knowledge of the temperature distribution within the vessel wall during laser irradiation is inevitable. The authors developed a finite element model (FEM) to simulate the temperature distribution within blood vessels during LTS. Temperature measurements were used to verify and calibrate the model. Different parameters such as laser power, solder absorption coefficient, thickness of the solder layer, cooling of the vessel and continuous vs. pulsed energy deposition were tested to elucidate their impact on the temperature distribution within the soldering joint in order to reduce the amount of further animal experiments. A pulsed irradiation with high laser power and high absorbing solder yields the best results.