[Extensive fibromata pendulantia. Hydrosurgery as a therapy option using the Versajet technique]. / Flächenhafte Fibromata pendulantia. Hydrochirurgie als Therapieoption mittels Versajet-Technik.

Fibromata pendulantia often appear as small filiform skin tags with a narrow pedicle in the neck, axilla and groin areas. Hitherto, extensive fibromata pendulantia were resected either surgically (curette, scissors, scalpel) or by laser. The present case study of an adipose patient with disseminated fibromata pendulantia in the axillary region in the setting of pseudoacanthosis nigricans introduces the Versajet hydrosurgery technique as an alternative method. It is able to remove tissue and rinse the wound simultaneously by means of a high-pressure water jet.

Relevance and Recent Developments of Chitosan in Peripheral Nerve Surgery.

Developments in tissue engineering yield biomaterials with different supporting strategies to promote nerve regeneration. One promising material is the naturally occurring chitin derivate chitosan. Chitosan has become increasingly important in various tissue engineering approaches for peripheral nerve reconstruction, as it has demonstrated its potential to interact with regeneration associated cells and the neural microenvironment, leading to improved axonal regeneration and less neuroma formation. Moreover, the physiological properties of its polysaccharide structure provide safe biodegradation behavior in the absence of negative side effects or toxic metabolites. Beneficial interactions with Schwann cells (SC), inducing differentiation of mesenchymal stromal cells to SC-like cells or creating supportive conditions during axonal recovery are only a small part of the effects of chitosan. As a result, an extensive body of literature addresses a variety of experimental strategies for the different types of nerve lesions. The different concepts include chitosan nanofibers, hydrogels, hollow nerve tubes, nerve conduits with an inner chitosan layer as well as hybrid architectures containing collagen or polyglycolic acid nerve conduits. Furthermore, various cell seeding concepts have been introduced in the preclinical setting. First translational concepts with hollow tubes following nerve surgery already transferred the promising experimental approach into clinical practice. However, conclusive analyses of the available data and the proposed impact on the recovery process following nerve surgery are currently lacking. This review aims to give an overview on the physiologic properties of chitosan, to evaluate its effect on peripheral nerve regeneration and discuss the future translation into clinical practice.

Two-component collagen nerve guides support axonal regeneration in the rat peripheral nerve injury model.

Progress in material development has enabled the production of nerve guides that increasingly resemble the characteristics of an autologous nerve graft. In the present study, 20 mm adult rat sciatic nerve defects were bridged with the collagen-based, two-component nerve guide 'Neuromaix', the commercially available NeuraGen® nerve tube or an autologous nerve graft. Neuromaix was able to support structural as well as functional regeneration across this gap. The majority of the axons grew across the scaffold into the distal nerve segment and retrograde tracing confirmed that these axons were of somatosensory and motor origin. Histomorphology revealed that axons regenerating through Neuromaix exhibited reduced myelin sheath thickness, whereas axon diameter and axon density were comparable to those of the autograft. Neuromaix implantation resulted in reinnervation of the gastrocnemius muscle to a level that was not significantly different from that supported by the autograft, as demonstrated by electrophysiology. Our findings show that the use of the Neuromaix scaffold not only allowed axonal regeneration across large nerve gaps, but that the regenerating axons were also able to functionally reinnervate the muscles. These data provide a promising perspective for the first in human application of the materials. Copyright © 2016 John Wiley & Sons, Ltd.

Efficient bridging of 20 mm rat sciatic nerve lesions with a longitudinally micro-structured collagen scaffold.

An increasing number of biomaterial nerve guides has been developed that await direct comparative testing with the 'gold-standard' autologous nerve graft in functional repair of peripheral nerve defects. In the present study, 20 mm rat sciatic nerve defects were bridged with either a collagen-based micro-structured nerve guide (Perimaix) or an autologous nerve graft. Axons regenerated well into the Perimaix scaffold and, the majority of these axons grew across the 20 mm defect into the distal nerve segment. In fact, both the total axon number and the number of retrogradely traced somatosensory and motor neurons extending their axons across the implant was similar between Perimaix and autologous nerve graft groups. Implantation of Schwann cell-seeded Perimaix scaffolds provided only a beneficial effect on myelination within the scaffold. Functional recovery supported by the implanted, non-seeded Perimaix scaffold was as good as that observed after the autologous nerve graft, despite the presence of thinner myelin sheaths in the Perimaix implanted nerves. These findings support the potential of the Perimaix collagen scaffold as a future off-the-shelf device for clinical applications in selected cases of traumatic peripheral nerve injury.

Bohr shift by lactic acid and the supply of O2 to skeletal muscle.

Conditions simulating changes during physical exercise were induced in erythrocytes to determine the resulting Bohr effect. Lactic acid was added to red cell suspensions and whole blood with initial 25 and 60% SO2, at 42 Torr PCO2, and temperatures of 20 and 37 degrees C. Changes in pH, PO2 and SO2 were measured. CO2 liberation from buffering lactic acid in the extracellular fluid and its diffusion into erythrocytes resulted in an exaggerated Bohr shift, if the gas could not escape from the liquid phase (closed system, 'muscle' conditions). PO2 at constant SO2 increased by up to 11.7%.mmol-1.L lactic acid. After reequilibration to initial PCO2 values (open system, 'lung' conditions) the Bohr shift decreased (remaining PO2 increase 0.7-1.4%.mmol-1.L) mainly caused by the reduced acidification. In addition, the Bohr coefficients (BC) under closed conditions were larger (-0.36 to -0.50) than after reequilibration (-0.20 to -0.38). This difference is attributed to a larger CO2 BC than fixed acid BC. These effects might be enhanced in vivo by temperature differences between muscle and lung, lowered nonbicarbonate buffering of blood and counter-current blood flow in muscle.

Glucocorticoids maintain the extracellular matrix of differentiated mammary tissue during explant and whole organ culture.

Mouse mammary whole organ culture (WOC) and explant culture of lactating tissue were used to investigate the mechanism by which glucocorticoids maintain secretory epithelium following lobuloalveolar development. The relative number of mammary epithelial cells expressing glucocorticoid receptors did not change with the loss of secretory epithelium during involution as demonstrated with competitive binding assays and immunohistochemistry for the glucocorticoid receptor. Furthermore, glucocorticoids did not inhibit AP-1 binding activity. However, Northern analysis demonstrated that genes associated with the breakdown of the extracellular matrix were not expressed in tissues cultured with glucocorticoids, in contrast to their upregulation during involution of mammary tissue cultured with insulin alone. Tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expression was lowest in tissue cultured in the presence of glucocorticoids and increased 2.3-, 3.4-, and 9-fold when tissues were involuted in the presence of insulin (Ins) alone, Ins and hydrocortisone (Hyd) with 0. 005 mg/ml, or 0.01 mg/ml collagenase IV, respectively. These data indicate that glucocorticoids maintain mammary differentiation in part by inhibiting the turnover of basement membrane.