Breaking down barriers: comprehensive functional analysis of the Aspergillus niger chitin synthase repertoire.

BACKGROUND: Members of the fungal kingdom are heterotrophic eukaryotes encased in a chitin containing cell wall. This polymer is vital for cell wall stiffness and, ultimately, cell shape. Most fungal genomes contain numerous putative chitin synthase encoding genes. However, systematic functional analysis of the full chitin synthase catalogue in a given species is rare. This greatly limits fundamental understanding and potential applications of manipulating chitin synthesis across the fungal kingdom. RESULTS: In this study, we conducted in silico profiling and subsequently deleted all predicted chitin synthase encoding genes in the multipurpose cell factory Aspergillus niger. Phylogenetic analysis suggested nine chitin synthases evolved as three distinct groups. Transcript profiling and co-expression network construction revealed remarkably independent expression, strongly supporting specific role(s) for the respective chitin synthases. Deletion mutants confirmed all genes were dispensable for germination, yet impacted colony spore titres, chitin content at hyphal septa, and internal architecture of submerged fungal pellets. We were also able to assign specific roles to individual chitin synthases, including those impacting colony radial growth rates (ChsE, ChsF), lateral cell wall chitin content (CsmA), chemical genetic interactions with a secreted antifungal protein (CsmA, CsmB, ChsE, ChsF), resistance to therapeutics (ChsE), and those that modulated pellet diameter in liquid culture (ChsA, ChsB). From an applied perspective, we show chsF deletion increases total protein in culture supernatant over threefold compared to the control strain, indicating engineering filamentous fungal chitin content is a high priority yet underexplored strategy for strain optimization. CONCLUSION: This study has conducted extensive analysis for the full chitin synthase encoding gene repertoire of A. niger. For the first time we reveal both redundant and non-redundant functional roles of chitin synthases in this fungus. Our data shed light on the complex, multifaceted, and dynamic role of chitin in fungal growth, morphology, survival, and secretion, thus improving fundamental understanding and opening new avenues for biotechnological applications in fungi.

The Manufacturing of 3D Printed models for the Neurotraumatological Education of Military Surgeons.

INTRODUCTION: When deployed abroad, military surgeons frequently have to deal with casualties involving head trauma. The emergency treatments, as well as craniotomies, are often performed by non-neurosurgeons qualified with basic neurotraumatological skills. Previous neurotrauma courses for education of non-neurosurgeons in Germany teach surgical emergency skills but do not include the training of skills needed to successfully utilize imaging in surgical planning, which is of importance for the safety and success of the treatment. To overcome these limitations, 3D printed models of neurotrauma cases were fabricated for application in the training of non-neurosurgeons. MATERIALS AND METHODS: Five models of actual neurotrauma cases from our neurosurgical department were segmented from CT scans and 3D printed using multi-part fused deposition modeling. Model quality was assessed with respect to the representation of pre-defined anatomical landmarks. The models were then fixed to a wooden mount with a central light source and covered by a latex mask for skin simulation. Surgical planning by means of craniometric measurements on the basis of available CT scans of the corresponding patients was then applied to the model. RESULTS: The 3D printed models precisely represented the cranium, the lesion, and anatomical landmarks, which are taken into consideration during surgical planning. Surface covering with washable latex masks ensured sufficient masking of the now non-noticeable lesion within the semi-translucent skull. Surgical planning was performed using washable marker drawings. When lighted, the otherwise non-visible lesion within the semi-translucent 3D printed craniums became visible and facilitated immediate success control for the course participants. CONCLUSION: The presented method provided a way to fabricate precise 3D models of neurotrauma cases, which are suitable to teach the application of medical imaging in surgical planning. For further benefit analysis, the application of the presented education tool needs to be investigated within a neurotrauma course.

Urgent need hybrid production - what COVID-19 can teach us about dislocated production through 3d-printing and the maker scene.

BACKGROUND: The COVID-19 pandemic has led to large-scale shutdowns in society. This resulted in global supply bottlenecks for medical protective equipment. The so-called Maker Movement recognized this emerging problem early on and, with the help of additive manufacturing (AM), began developing and manufacturing half masks or face shields as personal protective equipment (PPE). This knowledge has been made available in many places in form of open source product data, so that products could be adapted and improved, saving development time. METHODS: This production and innovation potential has been taken up and professionalized by the authors of this article. By means of a proof-of-principle we provide an overview of the possibility and successful unique introduction of a so-called professional "hybrid production" in a micro factory using 3D-printing at the place of greatest demand in a hospital by medical personnel to produce their own PPE. Furthermore the learning process and future benefits of on site 3D-printing are described. RESULTS: Our proof-of-principle successfully showed that the allocation of 3D-printing capabilities in the hospital infrastructure is possible. With assistance of the engineers, responsible for product design and development, the medical staff was able to produce PPE by means of AM. However, due to legal uncertainties and high material and production costs the usability is severely limited. CONCLUSIONS: The practical research showed that a complete implementation of the concept and the short-term establishment of a 3D-printing factory for the autonomous supply of a hospital with PPE was not feasible without further efforts. Nevertheless, it has enabled the medical staff to use AM technologies for future research approaches.

ioCT-guided percutaneous radiofrequency ablation for trigeminal neuralgia: how I do it.

BACKGROUND: Percutaneous trigeminal nerve rhizotomy is usually performed by free-handed puncture of the foramen ovale under radiographic control with the patient kept semiconscious. The procedure has thus been reported to be highly uncomfortable for both the patient and surgeon. To our knowledge, this is the first description of a technique that includes precise navigated, CT-guided puncture of the foramen with the patient in general anesthesia and confirmation of needle placement by intraoperative CT. METHOD: Radiofrequency ablation of the trigeminal nerve was guided by intraoperative CT navigation with neuromonitoring of trigeminal nerve function. The patient was kept under general anesthesia during the procedure. CONCLUSION: CT-guided percutaneous trigeminal nerve rhizotomy is a safe and efficient treatment strategy for the management of trigeminal neuralgia without the need of the patient being in a semiconscious state.

Hypertrophic pachymeningoencephalitis associated with temporal giant cell arteritis.

We report the rare case of an 80-year-old male patient with hypertrophic pachymeningoencephalitis that may be associated with temporal arteritis. The patient presented to our neurological department with a 2-week history of latent paresis and ataxia affecting his right hand. He had been diagnosed with temporal arteritis 12 years earlier. Brain MRI showed an enhancement of the left-sided frontoparietal meninges with oedema of the adjacent tissue of the precentral and postcentral cortex. A leptomeningeal biopsy was performed. An autoimmune-mediated immunoglobulin G4-associated hypertrophic pachymeningoencephalitis was diagnosed. The patient received a high-dose corticosteroid therapy and his symptoms gradually improved. Our results suggest that hypertrophic pachymeningoencephalitis may occur as a complication of giant cell arteritis and may cause central neurological deficits by cerebral perifocal oedema.

Outer electrospun polycaprolactone shell induces massive foreign body reaction and impairs axonal regeneration through 3D multichannel chitosan nerve guides.

We report on the performance of composite nerve grafts with an inner 3D multichannel porous chitosan core and an outer electrospun polycaprolactone shell. The inner chitosan core provided multiple guidance channels for regrowing axons. To analyze the in vivo properties of the bare chitosan cores, we separately implanted them into an epineural sheath. The effects of both graft types on structural and functional regeneration across a 10 mm rat sciatic nerve gap were compared to autologous nerve transplantation (ANT). The mechanical biomaterial properties and the immunological impact of the grafts were assessed with histological techniques before and after transplantation in vivo. Furthermore during a 13-week examination period functional tests and electrophysiological recordings were performed and supplemented by nerve morphometry. The sheathing of the chitosan core with a polycaprolactone shell induced massive foreign body reaction and impairment of nerve regeneration. Although the isolated novel chitosan core did allow regeneration of axons in a similar size distribution as the ANT, the ANT was superior in terms of functional regeneration. We conclude that an outer polycaprolactone shell should not be used for the purpose of bioartificial nerve grafting, while 3D multichannel porous chitosan cores could be candidate scaffolds for structured nerve grafts.

Temperature rise in the pulp chamber induced by a conventional halogen light-curing source and a plasma arc lamp.

PURPOSE: To assess and compare the pulp chamber temperature increase during resin-based composite polymerization with two different light-curing units. METHODS: A Class I cavity was prepared in an extracted lower molar under standardized conditions using a specially designed industrial robot system. The dentin layer between the pulp chamber and the floor of the cavity was 1 mm thick. Pulp chamber temperature rises (starting temperature: 20.0 +/- 0.1 degrees C) were recorded for four different series of investigations using both the halogen curing lamp Elipar Visio (light-curing: 40 s) and the plasma arc lamp Apollo 95E (light-curing: 3 seconds): Group A: Operation of the light-curing units directly over the untreated, empty cavity; Group B: Resin-based composite polymerization without previously applied cement base or bonding agent; Group C: Resin-based composite polymerization with a previously applied cement base; Group D: Resin-based composite polymerization with a previously applied bonding agent. In each of the four groups 10 measurements were carried out for every light-curing unit. Data were statistically analyzed using ANOVA, post-hoc Scheffé test and t-test. RESULTS: The lowest temperature increase (0.3 degrees C) was recorded during composite polymerization with a previously applied cement base using the Apollo 95E unit (Group C, P < 0.05). The highest temperature increase was induced when using the Elipar Visio unit directly over the untreated cavity (Group A, P < 0.05). In Groups A, C and D higher pulp chamber temperature measurements were obtained when using the Elipar Visio unit as compared to the Apollo 95E plasma arc lamp (P < 0.01). In Group B, no significant differences were recorded during the composite polymerization when using the two different light-curing units (P > 0.05).