An intra‐individual surgical wound comparison shows that octenidine‐based hydrogel wound dressing ameliorates scar appearance following abdominoplasty

Hypertrophic scar formation because of surgical procedures is associated with higher levels of pain, a lower quality of life, and poor cosmetic outcome and requires more resources in follow‐up management. An octenidine‐based hydrogel has been shown to modulate immunological function in an in vitro wound model, suggesting an improved scar formation. In this prospective, randomised, observer‐blinded, and intra‐patient‐controlled study, 45 patients who underwent abdominoplasty or mastectomy with transverse rectus abdominis muscle (TRAM) flap reconstruction were given both a standard postoperative wound dressing on one wound side and an octenidine‐based hydrogel with transparent film dressing, covered with standard postoperative dressing on the other side. Four instances of hypertrophia were reported in the gel side versus 12 in the standard dressing side. Visual Analogue Scale (VAS) pain scores taken during postoperative dressing changes showed reduced scores on the gel side at all time points. Vancouver Scar Scale (VSS) scores showed improvement in the gel side at 3, 6, and 12 months postoperatively. Skin distensibility measured using a cutometer showed significantly improved measures in gel‐treated wounds, similar to measures of healthy skin. Trans‐epidermal water loss (TEWL), measured using a tewameter, showed improved values on the gel side soon after surgery, with both the control and the gel side normalising after approximately 6 months. The octenidine‐based wound dressing demonstrates improved wound healing associated with a lower incidence of hypertrophic scar formation.     

Contact‐free monitoring of vessel graft stiffness – proof of concept as a tool for vascular tissue engineering

Tissue‐engineered vessel grafts have to mimic the biomechanical properties of native blood vessels. Manufacturing processes often condition grafts to adapt them to the target flow conditions. Graft stiffness is influenced by material properties and dimensions and determines graft compliance. This proof‐of‐concept study evaluated a contact‐free method to monitor biomechanical properties without compromising sterility. Forced vibration response analysis was performed on human umbilical vein (HUV) segments mounted in a buffer‐filled tubing system. A linear motor and a dynamic signal analyser were used to excite the fluid by white noise (0–200 Hz). Vein responses were read out by laser triangulation and analysed by fast Fourier transformation. Modal analysis was performed by monitoring multiple positions of the vessel surface. As an inverse model of graft stiffening during conditioning, HUV were digested proteolytically, and the course of natural frequencies (NFs) was monitored over 120 min. Human umbilical vein showed up to five modes with NFs in the range of 5–100 Hz. The first natural frequencies of HUV did not alter over time while incubated in buffer (p = 0.555), whereas both collagenase (?35%, p = 0.0061) and elastase (?45%, p < 0.001) treatments caused significant decreases of NF within 120 min. Decellularized HUV showed similar results, indicating that changes of the extracellular matrix were responsible for the observed shift in NF. Performing vibration response analysis on vessel grafts is feasible without compromising sterility or integrity of the samples. This technique allows direct measurement of stiffness as an important biomechanical property, obviating the need to monitor surrogate parameters. Copyright © 2016 John Wiley & Sons, Ltd.     

Secretin deficiency causes impairment in survival of neural progenitor cells in mice

Hippocampal neurogenesis is the lifelong production of new neurons in the central nervous system (CNS), and affects many physiological and pathophysiological conditions, including neurobehavioral disorders. The early postnatal stage is the most prominent neurogenesis period; however, the functional role of neurogenesis in this developing stage has not been well characterized. To understand the role of hippocampal neurogenesis in the postnatal developing period, we analyzed secretin, a neuropeptide, which is expressed significantly higher in the development stage. Secretin is a pleiotropic neuropeptide hormone that belongs to the secretin/VIP/glucagon peptide family. Although secretin was originally isolated in the gastrointestinal system, it has been found that secretin itself acts as a neuropeptide in the CNS. Here, we report a new function of secretin as a survival factor for neural progenitor cells in the hippocampus. We found that secretin-deficient mice exhibit decreased numbers of BrdU-labeled new neurons and dramatically increased apoptosis of doublecortin-positive neural progenitor cells in the subgranular zone of the dentate gyrus (DG) during the early postnatal period. Furthermore, we found that reduced survival of neural progenitor cells leads to decreased volume of DG, reduced long-term potentiation and impaired spatial learning ability in adults. Our studies demonstrate that secretin has important implications for neurogenesis in postnatal development, and affects neurobehavioral function in the adult mouse.     

Electrophysiologic assessment of sciatic nerve regeneration in the rat: surrounding limb muscles feature strongly in recordings from the gastrocnemius muscle

Striking inconsistencies between the results of morphometric and electrophysiologic examinations of the regenerating nerve were observed in a previous study featuring the bridging of a 14 mm gap in the rat sciatic nerve. To shed light on this dichotomy, seven further rats were subjected to permanent sciatic nerve transection and assessed electrophysiologically, histologically and by retrograde axonal tracing at various postoperative intervals (1 h to 8 weeks). The results of the histological examinations and retrograde tracing revealed that in spite of the fact that compound muscle action potentials could be recorded in the gastrocnemius muscle, no reinnervation of the gastrocnemius muscle, either physiological or aberrant, had actually taken place. Furthermore, it was established that the electrical activity recorded in the gastrocnemius muscle after stimulation of the proximal or distal stump is generated by surrounding hind limb muscles unaffected by denervation. These are stimulated either directly, or indirectly due to spreading of the impulse. It is therefore strongly recommended that caution should be exercised when interpreting recordings from the gastrocnemius muscle after stimulation of a regenerating sciatic nerve in laboratory rodents.     

Changes of EEG synchronization during low-frequency electric stimulation of the seizure onset zone

PURPOSE: To assess whether EEG synchronization changes during short-term low-frequency electrical stimulation of the seizure onset zone. METHODS: In 10 patients (34+/-11 years) with pharmaco-resistant epilepsy the seizure onset zone (9 temporal lobe, 1 frontal lobe) was electrically stimulated at 1Hz for 5min via intracranial electrodes. Bipolar stimuli were applied and four pulse widths (0.05, 0.1, 0.5, and 1.0ms) were tested. Stimulation amplitudes were held fixed at 1mA for strip electrodes and at 2mA for depth electrodes. Changes of EEG synchronization were assessed by the eigenvalue dynamics of the cross-correlation matrix computed from a 2.5s sliding window. RESULTS: 37 stimulations were performed. We observed EEG desynchronization in 49% (18/37), an increase of EEG synchronization in 27% (10/37) and an EEG pattern with no significant change of synchronization in 24% (9/37). EEG synchronization most frequently occurred when stimulating with a pulse width of 0.5ms. In a patient with bilateral independent seizure onsets stimulation effects on EEG synchronization were different for each side. In the patient with the shortest duration of temporal lobe epilepsy, stimulation triggered periodic epileptic spikes phase-locked to stimulation. One patient experienced an aura during stimulation, which did not evolve into a seizure, and in one patient a sub-clincial seizure occurred. DISCUSSION: Low-frequency stimulation of the seizure onset zone is associated with different changes of EEG synchronization and its effects depend on the widths of the stimulation pulses. It may be an appropriate stimulation technique for long-term studies assessing whether synchronized or desynchronized brain dynamics prevent seizure occurrence.     

Provider–patient interaction in rural Cameroon—How it relates to the patient's understanding of diagnosis and prescribed drugs,the patient's concept of illness,and access to therapy

Objective

This cross-sectional survey examines the relation between provider–patient interaction and several patient-outcomes in a rural health district in Cameroon.

Methods

We used structured patient interviews and the Roter Interaction Analysis System (RIAS) for analysis of audio-recorded consultations.

Results

Data from 130 primary care consultations with 13 health-care providers were analysed. 51% of patients correctly named their diagnoses after the consultation; in 47% of prescribed drugs patients explained correctly the purpose. Patients’ ability to recall diagnoses was related to the extent of clarity a provider used in mentioning it during consultation (recall rates: 87.5% if mentioned explicitly, 56.7% if mentioned indirectly and 19.2% if not mentioned at all; p < 0.001). Two thirds of patients were able to describe their concept of illness before the consultation, but only 47% of them mentioned it during consultations. On average patients who mentioned their disease concept were faced with more remarks of disapproval from providers (1.73 vs 0.63 per consultation; p < 0.01). Although 41% of patients admitted problems with financial resources to buy prescribed drugs, discussion about financial issues was very rare during consultations. Providers issued financial questions in 32%, patients in 21% of consultations.

Conclusion

This study shows that provider–patient interaction in primary health care in a rural Cameroon district deserves more attention. It might improve the patients’ knowledge about their health condition and support them in beneficial health behaviour.

Practice implications

Our findings should encourage providers to give more medical explanation, to discuss patients’ health beliefs in a non-judgemental manner, and to consider financial issues more carefully.