3D Bioprinting of Food Grade Hydrogel Infused with Living Pleurotus ostreatus Mycelium in Non-sterile Conditions

Mycelium is the root-like network of fungi. Mycelium biocomposites prepared by template replication (molding) can function as environmentally friendly alternatives to conventional polystyrene foams, which are energy- and carbon-intensive to manufacture. Recently, several studies have shown that 3D bioprinting technologies can be used to produce high value functional mycelium products with intricate geometries that are otherwise difficult or impossible to achieve via template replication. A diverse range of nutrients, thickeners, and gelling agents can be combined to produce hydrogels suitable for 3D bioprinting. 3D bioprinting with hydrogel formulations infused with living fungi produces engineered living materials that continue to grow after bioprinting is complete. However, a hydrogel formulation optimized for intricate 3D bioprinting of Pleurotus ostreatus mycelium, which is among the strains most commonly used in mycelium biocomposite fabrication, has yet to be described. Here, we design and evaluate a versatile hydrogel formulation consisting of malt extract (nutrient), carboxymethylcellulose and cornstarch (thickeners), and agar (gelling agent), all of which are easily sourced food grade reagents. We also outline a reproducible workflow to infuse this hydrogel with P. ostreatus liquid culture for 3D bioprinting of intricate structures comprised of living P. ostreatus mycelium and characterize the changes in height and mass as well as hardness of the prints during mycelium growth. Finally, we demonstrate that the workflow does not require a sterile bioprinting environment to achieve successful prints and that the same mycelium-infused hydrogel can be supplemented with additives such as sawdust to produce mycelium biocomposite objects. These findings demonstrate that 3D bioprinting using mycelium-based feedstocks could be a promising biofabrication technique to produce engineered living materials for applications such as mushroom cultivation, food preparation, or construction of the built environment.

Automated and app-based activation of first responders for prehospital cardiac arrest: an analysis of 16.500 activations of the KATRETTER system in Berlin

BACKGROUND

Bystander CPR is one of the main independent factors contributing to better survival after out-of-hospital cardiac arrest. Simultaneously, the rate of bystander CPR in Germany is below the European average. First responder applications (apps) contribute to reducing the time period without CPR (no-flow time) until professional help can arrive on-scene.

METHODS

The KATRETTER app was introduced in Berlin as one of the first apps in Europe which do not require any medical qualifications to register as a first responder. The activation of volunteer first responders for suspected cardiac arrest cases through the Berlin Emergency Medical Services integrated control center was evaluated based on data collected between 16 Oct 2020 and 16 Oct 2022. Our descriptive analysis includes the number of registered first responders, number of activations, the number and percentages of accepted activations, as well as all reports where first responders arrived at the scene.

RESULTS

As of 15 Oct 2022, a total of 10,102 first responders were registered in the state of Berlin. During this specified period, there were 16.505 activations of the system for suspected out-of-hospital cardiac arrest. In 38.4% of the accepted cases, first responders documented patient contact, and in 34.6% of cases with patient contact, CPR was performed. Only 2% of registered first responders did not have any medical qualifications.

CONCLUSIONS

Smartphone-based first responder applications should not be understood as a means of alerting professional help, but rather like a digitally amplified "call for help" in the vicinity of an emergency location. A large number of first responders can be recruited within 24 months, without large-scale public relations work necessary. No qualifications were required to become a first responder, contributing to a low-threshold registration process with the effect of a more widespread distribution of the app and cost reduction during implementation.

Surgical Treatment of Osteochondral Lesions of the Tibial Plafond: A Systematic Review and Meta-Analysis

BACKGROUND

The literature on osteochondral lesions of the tibial plafond (OLTPs) is sparse. The aim of this study was therefore to provide an overview of clinical and radiological outcomes following treatment of OLTPs.

METHODS

We performed a systematic search of the MEDLINE, Embase, and Cochrane library databases. The review was performed in accordance with the PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) guidelines and included all original articles on treatment outcomes for OLTPs. The methodological quality of the articles was assessed using the Methodological Index for Non-Randomized Studies (MINORS). Baseline patient and lesion characteristics were pooled and weighted according to the number of lesions per study. The primary outcome was any clinical or patient-reported outcome measure pooled by treatment method when separable data were available. Secondary outcomes were complications, reoperation rates, radiological outcomes, and sport outcomes.

RESULTS

The search yielded 2,079 articles, of which 10 studies (1 prospective case series, 1 retrospective comparative study, and 8 retrospective case series) with a total of 175 patients were included. The overall methodological quality of the studies was low. All patients were treated surgically; 96% of the lesions were primary cases (i.e., first-time surgery) and 58% were solitary tibial lesions (i.e., no opposing talar lesion). Arthroscopic bone marrow stimulation was the most frequently used treatment strategy (51%), followed by cartilage transplantation (17%), chondrogenesis-inducing techniques (11%), osteochondral transplantation (3%), retrograde drilling (3%), and mixed (i.e., inseparable) treatments (15%). The clinical outcomes of the different surgical therapies were considered to be moderate to good. The pooled postoperative AOFAS (American Orthopaedic Foot & Ankle Society) score for bone marrow stimulation and osteochondral transplantation was 54.8 (95% confidence interval [CI], 49.5 to 85.0) (n = 14) and 85.3 (95% CI, 56 to 100) (n = 3), respectively. Overall, complications and reoperations were rarely reported. The pooled complication and reoperation rates could only be calculated for bone marrow stimulation and were 5% and 7%, respectively.

CONCLUSIONS

Surgical interventions for OLTPs appear to yield moderate to good clinical outcomes. Bone marrow stimulation resulted in a moderate AOFAS score. Complications and reintervention rates were found to be low. The current evidence in the literature is limited because of the underreporting of clinical, radiological, and sport data and the heterogenous outcome scores reported.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

[Introduction of emergency paramedic investigators in the context of the COVID-19 pandemic in the Berlin emergency medical service]

BACKGROUND

It has been shown throughout the COVID-19 pandemic that the condition of a number of patients deteriorates acutely when not monitored. This is set against an increased demand for emergency medical services and the resulting scarcity of resources, which makes it necessary to prioritise inpatient treatment or ensure that patients are provided with appropriate outpatient care. In this context, the Berlin Fire Department has introduced emergency paramedic investigators (NotSan-Erkunder) as an additional operating resource.

METHODOLOGY

We assessed all operations from 28.03.2020 to 28.04.2020 during which Emergency Paramedic Investigators of the Berlin emergency services were deployed. A total of 341 operations were included from the 31 days. Alongside data from the dispatch system, all operational documentation was assessed.

RESULTS

In 57% of cases, mNACA II patients (outpatient treatment) were identified, in 42% of cases, mNACA III patients (inpatient treatment) were identified, and in 1% of cases, mNACA IV (imminent danger to life) patients were identified. In 51% of cases, the emergency services transported the patient to a hospital, and in 49%, alternative care measures were employed. These included referral to a local physician in 28% of cases. In 11% of cases, patients were referred to on-call services of the Association of Statutory Health Insurance Physicians (KV in German). In 4% of cases, the Berlin Fire Department emergency dispatch center deployed a physician of the KV (KV-ARE investigator).

DISCUSSION

The results show that additional operational resources serve an important function during a pandemic with regards to an initial assessment and pilot function. This can help relieve not only the emergency services but also the medical facilities responsible for providing further care. The standardised dispatch enquiry enables the linking with the appropriate codes from the low-priority operational spectrum and support by a Tele-emergency physician lends additional professional competency to the emergency paramedics.

[Indications, procedure and outcome of prehospital emergency resuscitative thoracotomy-a systematic literature search]

BACKGROUND

Prehospital resuscitative thoracotomy (PHRT) is a controversially discussed measure for the acute treatment of traumatic cardiac arrest (TCA) recommended by the current guidelines of the European Resuscitation Council (ERC). The aim of this work is the comprehensive presentation and summary of the available literature with the underlying hypothesis that the available publications show the feasibility and survival following PHRT in patients with TCA with a good neurological outcome.

METHOD

A systematic literature search was performed in the databases PubMed, EMBASE, Google Scholar, Springer LINK and Cochrane. The study selection, data extraction and evaluation of bias potential were performed independently by two authors. The outcome of patients with TCA after PHRT was selected as the primary endpoint.

RESULTS

A total of 4616 publications were found of which 21 publications with a total of 287 patients could be included in the analyses. For a detailed descriptive analysis, 15 publications with a total of 205 patients were suitable. The TCA of these patients was most commonly caused by pericardial tamponade, thoracic vascular injuries and severe extrathoracic multiple injuries. In 24% of the cases TCA occurred in the presence of the emergency physician. Clamshell thoracotomy (53%) was used preclinically more often than anterolateral thoracotomy (47%). Of the PHRT patients after TCA 12% (25/205) left the hospital alive, 9% (n = 19/205) with good neurological outcome and 1% (n = 3/205) with poor neurological outcome (according to the Glasgow outcome scale, GOS).

CONCLUSION

The prognosis of TCA seems to be much better than has long been assumed. Decisive for the success of resuscitation efforts in TCA seems to be the immediate, partly invasive treatment of all reversible causes. The measures for TCA recommended by the ERC resuscitation guidelines, seem to be poorly implemented, especially in the preclinical setting. A controversy regarding the recommendations of the guidelines is the question of whether a PHRT can be successfully implemented and if the comprehensive introduction in Germany seems to be meaningful. Despite the recommendation of the guidelines, this systematic review and meta-analysis underlines the lack of high-quality evidence on PHRT, whereby a survival probability to hospital discharge of 12% was reported, of which 75% had a good neurological outcome. The risk of bias of the results in individual publications as well as in this review is high. Further systematic research in the field of preclinical trauma resuscitation is particularly necessary also for acceptance of the guidelines.

[Validation of the Osteomyelitis Diagnosis Score on the Basis of a Retrospective Analysis of 100 Patients with Non-Union of the Tibia]

Background: The accurate diagnosis of "osteomyelitis" is difficult and is often delayed. However, early and radical therapy of osteomyelitis is essential. The osteomyelitis diagnosis score (ODS) was developed to predict the probability of osteomyelitis. The aim of our study was to validate the ODS and to investigate its practicability in daily routine. Material and Methods: The ODS is based on five diagnostic procedures: 1. clinical history/risk factors, 2. clinical examination/laboratory results, 3. diagnostic imaging, 4. microbiology and 5. histopathology. Each diagnostic procedure includes numerous individual findings, which are rated with 1-6 points, depending on their relevance. If the sum of the five diagnostic criteria is ≥ 17 points, the diagnosis "osteomyelitis" can be viewed as safe, between 8-17 points as probable and between 2-7 points as possible. This retrospective study included 100 patients with non-union of the tibia (2002-2010). The patients were classified into two groups: septic non-union of the tibia (experimental intervention; gold standard: positive detection of bacteria and/or positive histology) and aseptic non-union of the tibia (control intervention; no detection of bacteria and/or histology). Epidemiological data, the score's total number of points and the number of points of the score's five diagnostic procedures were analysed. Results: 71 patients exhibited aseptic non-union of the tibia, 29 patients septic non-union. Patients with septic non-union obtained a mean of 20.8 points, and 24 at least 18 points; the diagnosis "osteomyelitis" is then presumed to be certain. Patients with aseptic non-union obtained a mean of 11.3 points, and only 3/71 patients received > 17 points. Both groups obtained the majority of points in the diagnostic procedure "clinical history". The difference between the two groups is highly significant (p < 0.001). The score's sensitivity is 82.8 %, with a specificity of 95.8 %. Conclusion: The ODS was proved to be a valid score. Patients with septic non-union were identified, even if bacteria were not detected. However, the use of the ODS is demanding, as there are 104 individual findings. Many of these individual findings were negative in all patients. It would be desirable to optimise ODS, by reducing the number of queried parameters, without reduction sensitivity.

Über die Feldstärkeabhängigkeit der Winkelverteilung feldemittierter Elektronen und Ionen

The angular distribution of atoms and molecules field ionized at Platinum tips is determined. First, with negative polarity of the tip the angular distribution of the field emitted electrons is measured in order to determine he radius of curvature and the shape of the tip, using calculations of DRECHSLER and HENKEL 2.

Then the angular distribution of field ionized Argon is measured at a tip temperature of about 400 °K. The curve agrees qualitatively with one derived from GOMER’s 6 equations on field ion currents as a function of field strength.

In contrast with this curve which shows a continuous decay with polar angle, the angular distribution curve of field ionized n-hexane, acetone, water and methanol shows a side-maximum lying at a polar angle of about 40°. This is explained as the consequence of adsorption and particle supply phenomena.

[S3 guideline on treatment of polytrauma/severe injuries. Initial surgical phase: significance--possibilities--difficulties?]

There is no universal, generally established strategy for polytrauma management in Germany until now. The new S3 guideline on polytrauma patient care is the first high-level evidence-based compendium consented to by all major medical societies in Germany. This report emphasises all new guideline recommendations concerning the early operative care of multiply injured patients. With regard to the available evidence in the literature this report shows that the assessment of key recommendations is often difficult due to a lack of data. For guideline explanations with the highest grade of recommendation however it can be assumed that there is no alternative and that these will be implemented nationwide. This study also shows that the absolute and relative number of recommendations and the corresponding grade of recommendation do not correlate with the frequency and severity of injuries in an average polytrauma patient. It will now become a major challenge in German trauma care to incorporate all S3 guideline recommendations into the local treatment algorithms. Regional trauma networks could play a key role in this crucial task.

Le ménisque discoïde chez l’enfant: aspects échographiques

OBJECTIVE

Discoid meniscus is a rare congenital pathology affecting mainly the lateral meniscus. Radiological diagnosis, initially based on arthrographic findings, is now established on well defined MRI criteria. In this study, ultrasonography (US) was the modality proposed for diagnosing discoid meniscus and compared to the normal sonographic meniscal pattern. Subjects and methods. 8 children aged from 6 to 11 years, with a symptomatology highly suggestive of meniscal pathology, were investigated by US of both knees, followed by MRI in 3 and arthroscopy in all cases.

RESULTS

In all 8 cases, a meniscus was diagnosed as discoid when it no longer had its normal triangular shape, was abnormally elongated and thick and demonstrated a heterogeneous central pattern. Associated lesions (fracture, cystic degeneration) were well demonstrated on US. The lateral meniscus was involved in all 8 cases, the pathology was bilateral in 5 cases and MRI/US correlation was good in 3 cases. Arthroscopy confirmed US findings in all cases.

CONCLUSION

US, a more widely available imaging modality, is a reliable technique for the diagnosis of discoid meniscus in children.

Surface characterization of fluorinated polymers (PTFE, PVDF, PFA) for use in ultratrace analysis

Surface characterization of new unused PTFE, PFA and PVDF labware has been carried out by light microscopy, scanning electron microscopy, profilometry and atomic force microscopy. It has been found that in spite of higher micro-roughness, PFA exhibits the lowest nano-roughness and hence seems best suited as vessel material for relatively mild pressureless chemical operations for sample preparation of ultrapure substances, as container material for storage of ultrapure liquids, and for transport of such liquids, e.g., from the producer in the chemical to the end user in the microelectronics industry. This suitability refers only to the surface quality of the investigated materials. PTFE-surfaces, due to the sintering process of production, exhibit the most unfavourable surface quality of the investigated fluorinated polymers.

Id gene expression during development and molecular cloning of the human Id-1 gene

Id genes encode helix-loop-helix proteins that inhibit transcription by forming inactive heterodimers with basic helix-loop-helix (bHLH) proteins. bHLH proteins normally form either homodimers or heterodimers with other bHLH proteins and bind to a DNA sequence element activating transcription. Id-containing heterodimers are inactive because Id proteins lack the basic amino acid region necessary to form a DNA-binding domain. We have examined the relative levels of Id-1 and Id-2 mRNA during normal development and in malignant tissues. In the course of these experiments we cloned and sequenced the human Id-1 cDNA. Two related cDNA molecules encoding human Id-1 mRNAs were identified. Id-1a is a cDNA of 958 nucleotides and can encode a protein of 135 amino acids. Id-1b cDNA is 1145 nucleotides, can encode a protein of 149 amino acids, and appears to be a splice variant of Id-1a. The amino acid sequence of human Id-1 is greater than 90% homologous to that of mouse Id-1. The patterns of Id-1 and Id-2 expression during mouse development vary widely, and we detected Id-1 expression in human fetal and adult tissues from lung, liver, and brain. High Id-1 mRNA expression was found in many human tumor cell lines, including those isolated from nervous system tumors. We mapped Id-2 to human chromosome 2p25.

Stimulation of lymphocyte proliferation to monitor fractionation of thymus extracts

Multi-step fractionations by solvent extractions, gel filtrations, ion-exchange chromatography, etc., of bovine thymus extracts were monitored by a standardized assay, in vitro, which led to the described peptides, thymones A, B and C. The assay uses spleen cells from neonatally thymectomized mice as tissue relevant to immunoregulation. Assay of incorporation of [3H]-thymidine into DNA located peaks of activities. Calf thymus outer fraction ("CTO") showed activity, but Fraction 5, synthetic thymosin alpha 1, [G1n1]-FTS, and glutathione, were inactive in this assay.

[Fermentative degradation of 2-14C-mannose with Leuconostoc mesenteroides (author's transl)]

Mannose-2-14C has been fermented by Leuconostoc mesenteroides, CO2 ethanol and D-lactic acid were formed in a molar ratio of 1:1:1. A small amount of acetic acid was found as by-product. It could easily be isolated from the main products of the fermentation and it did not disturb further degradation procedures. The methyl-C-atom of ethanol, which was derived from C-2 of the mannose, had nearly the same specific radioactivity as mannose-2-14C. All other C-atoms of the degradation products were only very slightly labeled. Their content of radioactivity was in any case lower than 3% of the specific radioactivity of the degraded mannose. This procedure is applicable for the degradation of 14C-labeled mannose.