Challenging applicability of ISO 10993-5 for calcium phosphate biomaterials evaluation: Towards more accurate in vitro cytotoxicity assessment

Research on biomaterials typically starts with cytocompatibility evaluation, using the ISO 10993-5 standard as a reference that relies on extract tests to determine whether the material is safe (cell metabolic activity should exceed 70 %). However, the generalized approach within the standard may not accurately reflect the material's behavior in direct contact with cells, raising concerns about its effectiveness. Calcium phosphates (CaPs) are a group of materials that, despite being highly biocompatible and promoting bone formation, still exhibit inconsistencies in basic cytotoxicity evaluations. Hence, in order to test the cytocompatibility dependence on different experimental setups and material-cell interactions, we used amorphous calcium phosphate, α-tricalcium phosphate, hydroxyapatite, and octacalcium phosphate (0.1 mg/mL to 5 mg/mL) with core cell lines of bone microenvironment: mesenchymal stem cells, osteoblast-like and endothelial cells. All materials have been characterized for their physicochemical properties before and after cellular contact and once in vitro assays were finalized, groups identified as 'cytotoxic' were further analyzed using a modified Annexin V apoptosis assay to accurately determine cell death. The obtained results showed that indirect contact following ISO standards had no sensitivity of tested cells to the materials, but direct contact tests at physiological concentrations revealed decreased metabolic activity and viability. In summary, our findings offer valuable guidelines for handling biomaterials, especially in powder form, to better evaluate their biological properties and avoid false negatives commonly associated with the traditional standard approach.

Quantitative measurement of influenza virus transmission in animal model: an overview of current state

Influenza virus transmission is a crucial factor in understanding the spread of the virus within populations and developing effective control strategies. Studying the transmission patterns of influenza virus allows for better risk assessment and prediction of disease outbreaks. By monitoring the spread of the virus and identifying high-risk populations and geographic areas, it is possible to allocate resources more effectively, implement timely interventions, and provide targeted healthcare interventions to diminish the burden of influenza virus on vulnerable populations. Theoretical models of virus transmission are used to study and simulate of influenza virus spread within populations. These models aim to capture the complex dynamics of transmission, including factors such as population size, contact patterns, infectiousness, and susceptibility. Animal models serve as valuable tools for studying the dynamics of influenza virus transmission. This article presents a brief overview of existing research on the qualitative and quantitative study of influenza virus transmission in animal models. We discuss the methodologies employed, key insights gained from these studies, and their relevance.

Efficient inactivation of harmful algae K. mikimotoi by a novel algicidal bacterium via a rare direct contact pathway: Performances and mechanisms

Harmful algal blooms (HABs) caused by Karenia mikimotoi have posed great threats to marine ecosystems, and algal inactivation by symbiotic bacteria has been recognized as environmental benign methods for controlling HABs. However, the identified algicidal bacteria for K. mikimotoi is limited and exclusively based on indirect algicidal pathways, which may cause secondary pollution due to releasing toxic algicidal agents. In this study, a novel strain of algicidal bacteria Tenacibaculum sp. GD3 was isolated from the phycosphere of K. mikimotoi. The bacterial strain GD3 could achieve 92.6 % of inactivation efficiency against K. mikimotoi within 8 h of co-culturing period, which outperformed those in existing literatures reported so far. The algicidal mechanisms were revealed to be a rare direct cell-to-cell contact pathway, and the GD3 could grow by utilizing metabolites from K. mikimotoi, exhibiting excellent bacterial adaptability in the phycosphere. Cell morphology changes were monitored by live cell imaging system combined with SEM and TEM observations, which showed that the GD3 was first attached to the algal cell membrane, followed by lipid peroxidation and lysis of membrane protein. Oxidative stress responses were induced as reveled by up-regulation of intracellular ROSs and antioxidant enzyme activity. Photosynthetic parameters including rETR_max, F_v/F_m, YII and NPQ were reduced, and expression of functional genes involved in decomposition of chlorophyll and cell wall was significantly suppressed. Moreover, the intracellular release profile and acute toxicity assessment indicated that the GD3 could also detoxify the K. mikimotoi cultures and the released biomolecules would not cause adverse effect to marine environment. This study not only provides a novel algicidal bacterium against K. mikimotoi via a rare direct mode, but also helps to better understand the algicidal mechanisms at physiological and genetic level, thus moving forward the areas of HABs control by microbiological strategies.

Optimizing communication strategies and designing a comprehensive program to facilitate cascade testing for familial hypercholesterolemia

BACKGROUND

This project aimed to optimize communication strategies to support family communication about familial hypercholesterolemia (FH) and improve cascade testing uptake among at-risk relatives. Individuals and families with FH provided feedback on multiple strategies including: a family letter, digital tools, and direct contact.

METHODS

Feedback from participants was collected via dyadic interviews (n = 11) and surveys (n = 98) on communication strategies and their proposed implementation to improve cascade testing uptake. We conducted a thematic analysis to identify how to optimize each strategy. We categorized optimizations and their implementation within the project's healthcare system using a Traffic Light approach.

RESULTS

Thematic analysis resulted in four distinct suggested optimizations for each communication strategy and seven suggested optimizations that were suitable across all strategies. Four suggestions for developing a comprehensive cascade testing program, which would offer all optimized communication strategies also emerged. All optimized suggestions coded green (n = 21) were incorporated. Suggestions coded yellow (n = 12) were partially incorporated. Only two suggestions were coded red and could not be incorporated.

CONCLUSIONS

This project demonstrates how to collect and analyze stakeholder feedback for program design. We identified feasible suggested optimizations, resulting in communication strategies that are patient-informed and patient-centered. Optimized strategies were implemented in a comprehensive cascade testing program.

Impact of an auditory hallucination simulation coupled with a speaker diagnosed with schizophrenia on mental illness stigma in pharmacy students

INTRODUCTION

Hallucination simulations improve student empathy but increase desired social distance from individuals with schizophrenia, while direct contact reduces social distance. This study describes the implementation of combining an auditory hallucination simulation with a speaker diagnosed with schizophrenia and its impact on mental illness stigma.

METHODS

Pharmacy students in their last year of didactic instruction (N = 346) attended a presentation by a speaker diagnosed with schizophrenia then participated in a hallucination simulation. Mental illness stigma was measured before and after the intervention using the Opening Minds Survey for Health Care Professionals (OMS-HC). Related-samples Wilcoxon-signed rank tests were used to evaluate changes in OMS-HC scores. An inductive qualitative analysis was conducted on student perceptions of patients with psychosis.

RESULTS

OMS-HC total scores were reduced by an average of 2.0 ± 5.6 (P = .005) for the first-year pilot and 2.3 ± 7.0 (P < .001) for the subsequent year. OMS-HC attitudes (P = .005) and disclosure/help-seeking (P < .005) subscales decreased both years. There was no significant change in the social distance subscale (P = .205) the first year and a significant decrease (P = .015) the second year. The themes identified from the open-ended comments were increased awareness, sympathy, empathy, inspiration/admiration, discomfort, and change to patient care.

CONCLUSIONS

The combination of a speaker with schizophrenia and auditory hallucination simulation effectively reduced mental illness stigma. The combination is likely effective for reducing stigmatizing attitudes and willingness to disclose mental illness with variable reduction in desired social distance.

Contrasting regulation of live Bacillus cereus No.1 and its volatiles on Shiraia perylenequinone production

BACKGROUND

Fungal perylenequinones (PQs) are a class of photoactivated polyketide mycotoxins produced by plant-associated fungi. Hypocrellins, the effective anticancer photodynamic therapy (PDT) agents are main bioactive PQs isolated from a bambusicolous Shiraia fruiting bodies. We found previously that bacterial communities inhabiting fungal fruiting bodies are diverse, but with unknown functions. Bacillus is the most dominant genus inside Shiraia fruiting body. To understand the regulation role of the dominant Bacillus isolates on host fungus, we continued our work on co-culture of the dominant bacterium B. cereus No.1 with host fungus Shiraia sp. S9 to elucidate bacterial regulation on fungal hypocrellin production.

RESULTS

Results from "donut" plate tests indicated that the bacterial culture could promote significantly fungal PQ production including hypocrellin A (HA), HC and elsinochrome A-C through bacterial volatiles. After analysis by gas chromatograph/mass spectrometer and confirmation with commercial pure compounds, the volatiles produced by the bacterium were characterized. The eliciting roles of bacterial volatile organic compounds (VOCs) on HA production via transcriptional regulation of host Shiraia fungus were confirmed. In the established submerged bacterial volatile co-culture, bacterial volatiles could not only promote HA production in the mycelium culture, but also facilitate the release of HA into the medium. The total production of HA was reached to 225.9 mg/L, about 1.87 times that of the fungal mono-culture. In contrast, the live bacterium suppressed markedly fungal PQ production in both confrontation plates and mycelium cultures by direct contact. The live bacterium not only down-regulated the transcript levels of HA biosynthetic genes, but also degraded extracellular HA quickly to its reductive product.

CONCLUSION

Our results indicated that bacterial volatile release could be a long-distance signal to elicit fungal PQ production. Biodegradation and inhibition by direct contact on fungal PQs were induced by the dominate Bacillus to protect themselves in the fruiting bodies. This is the first report on the regulation of Bacillus volatiles on fungal PQ production. These findings could be helpful for both understanding the intimate fungal-bacterial interactions in a fruiting body and establishing novel cultures for the enhanced production of bioactive PQs.

Direct contact, dissolution and generation of reactive oxygen species: How to optimize the antibacterial effects of layered double hydroxides

Infections by pathogenic bacteria have been threatening several fields as food industries, agriculture, textile industries and healthcare products. Layered double hydroxides materials (LDHs), also called anionic clays, could be utilized as efficient antibacterial materials due to their several interesting properties such as ease of synthesis, tunable chemical composition, biocompatibility and anion exchange capacity. Pristine LDHs as well as LDH-composites including antibacterial molecules and nanoparticles loaded-LDHs were proven to serve as efficient antibacterial agents against various Gram-positive and Gram-negative bacterial strains. The achieved antibacterial effect was explained by the following mechanisms: (1) Direct contact between the materials and bacterial cells driven by electrostatic interactions between positively charged layers and negatively charged cell membranes, (2) Dissolution and gradual release over time of metallic ions or antibacterial molecules, (3) Generation of reactive oxygen species.

Bactericidal activity of immobilized silver nanoparticles on silica substrates with different sizes

Hybrid particles with immobilized silver nanoparticles (AgNPs) receive a lot of attention due to their excellent antibacterial activity with the prevention of inherent aggregation of AgNPs. In this study, serial sized silica substrate particles (231, 401, and 605 nm) and their corresponding hybrid particles with AgNPs (~ 30 nm) are prepared, with detailed bactericidal images of the corresponding particles at various times. Their bactericidal activity is elucidated for both Gram-positive Streptococcus agalactiae and Gram-negative Escherichia coli CN13, which show the size of 0.8 μm × 0.9 μm and 1.3 μm × 1.8 μm, respectively. There is a large difference in the bactericidal activity between the smallest (231 nm, 3-log₁₀ reduction) and larger (401 and 605 nm, 6-log₁₀ reduction) silica substrates, whereas there is hardly a difference between the latter. Their effective total surface area (ETSA) is considered important for their bactericidal activity, based on the nearly equal large ETSA of the well-dispersed two larger silica substrates and the much smaller ETSA of the agglomerated smallest substrates. Submicron-sized pits appear on the bacterial membrane by direct contact with the hybrid particles, implicating the importance of ETSA. Still, further research is needed with much different silica substrate sizes to fully elucidate the impact of the silica substrate on the bactericidal activity of immobilized AgNPs.

Direct Contact with Platelets Induces Podoplanin Expression and Invasion in Human Oral Squamous Cell Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is mostly diagnosed at an advanced stage, with local and/or distal metastasis. Thus, locoregional and/or local control of the primary tumor is crucial for a better prognosis in patients with OSCC. Platelets have long been considered major players in cancer metastasis. Traditional antiplatelet agents, such as aspirin, are thought to be potential chemotherapeutics, but they need to be used with caution because of the increased bleeding risk. Podoplanin (PDPN)-expressing cancer cells can activate platelets and promote OSCC metastasis. However, the reciprocal effect of platelets on PDPN expression in OSCC has not been investigated. In this study, we found that direct contact with platelets upregulated PDPN and integrin β1 at the protein level and promoted invasiveness of human OSCC Ca9.22 cells that express low levels of PDPN. In another human OSCC HSC3 cell line that express PDPN at an abundant level, silencing of the PDPN gene reduced cell invasiveness. Analysis of the public database further supported the co-expression of PDPN and integrin β1 and their increased expression in metastatic tissues compared to normal and tumor tissues of the oral cavity. Taken together, these data suggest that PDPN is a potential target to regulate platelet-tumor interaction and metastasis for OSCC treatment, which can overcome the limitations of traditional antiplatelet drugs.

Membrane distillation for concentrated blackwater: Influence of configuration (air gap, direct contact, vacuum) on selectivity and water productivity

Water recovery from concentrated blackwater has been studied using air gap (AGMD), direct contact (DCMD) and vacuum membrane distillation (VMD) to deliver decentralised sanitation. Whilst good water quality was achieved with each configuration, differences in the rejection of volatile compounds was observed. VMD exhibited the highest rejection of volatiles, specifically ammoniacal nitrogen, of all the configurations but fouling inhibited total flux. DCMD exhibited a temperature dependent volatile rejection which resulted in poor rejection at lower feed temperatures (≤40 °C). AGMD was identified as the most promising configuration for application within decentralised sanitation, since the rejection of volatiles was consistent over a range of operating temperatures with ammonia rejection directly related to solution pH. An increase in organic colloids and particles due to faecal contamination reduced COD removal due to the induction of wetting, but was shown to be offset by adoption of a smaller pore size (0.1 μm), and when complemented with upstream solid-liquid separation within a fully integrated system, will provide a robust sanitation solution. Importantly, this work has shown that AGMD can recover water from concentrated blackwater close to international discharge and reuse regulations in a single stage process; this is significant as blackwater consists of only urine and faeces, and is thus 40 times more concentrated than municipal sewage. It is proposed that the water quality produced reflects a step change to delivering safe sanitation, and is complemented by a simple method for heat recovery integration this is similarly advantageous for resource constrained environments common to decentralised sanitation solutions.

Process optimization and transfer of freeze-drying in nested vial systems

Scale-up and transfer of freeze-drying processes is a crucial challenge in biopharma industry. With the success of small batch processing lines utilizing rack vial holding systems, further detailed knowledge about freeze-drying cycles and their scale-up for vials in a rack is required. Therefore, product temperature (T_P) profiles as well as Kv values of vials nested in a Polyetheretherketon (PEEK) rack were compared to those of vials placed in a commonly used stainless steel tray. Additionally, both setups were challenged with varying fill volume and partially versus fully loaded rack. Additionally, a process developed for rack was compared to a tray freeze-drying cycle. Freeze-drying in vials placed in the rack is markedly faster for center vials and more homogeneous compared to vials in bulk tray setting, as indicated by T_P and Kv values. Due to the more homogeneous drying the rack is more flexible regarding variation of the fill volume. The key point for the transfer of a freeze-drying cycle from rack to tray is to consider the higher sublimation rates in the rack by adapting chamber pressure or shelf temperature for the tray. Furthermore, transfer from one rack per shelf in a laboratory freeze-dryer to pilot scale with four racks per shelf was successful. Thus, understanding of the process in rack and tray setup was enhanced to ensure efficient scale-up and transfer of freeze-drying processes.

Trouble With the Neighbor During Freeze-Drying: Rivalry About Energy

Batch homogeneity during lyophilization is crucial to ensure products with high quality. Known as edge-vial-effect, vials at the corners and edges tend to run warmer than center vials during primary drying. This is associated with risk of collapse or increased costs due to use of more conservative, longer drying conditions resulting in lower product temperature. The edge-vial-effect has been attributed to radiation coming from the chamber wall. We could show that the neighbor vial has a dominant impact on product temperature during lyophilization. Depending on the number of neighbors as well as the distance to a neighbor vial, the neighbor vial exerts a remarkable cooling effect. Energy transfer by gas conduction enables the cooling effect of a neighboring vial over a distance up to 10 mm. This not only leads to prolonged primary drying but also impacts cake appearance. Thus, to avoid trouble during lyophilization you have to watch out for the neighborhood.

Computational Modelling of the Bioheat Transfer Process in Human Skin Subjected to Direct Heating and/or Cooling Sources: A Systematic Review

The purpose of this systematic review is to analyze characteristics and methodologies utilized in bioheat transfer models of human skin to provide state-of-the-art knowledge on the topic. This review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. PubMed, EMBASE and Web of Science databases were searched up to May 30th, 2019 for bioheat transfer models focusing on direct contact between skin and temperature (heat and/or cold) source. Ten studies were included. A 16-item checklist was used to assess their methodological quality. Four studies analyzed healthy skin and six included pathological conditions. All determined skin's thermal behavior, and studies including pathological conditions also analyzed burn damage. Studies did not present a wide variety of mathematical formulation, emphasizing on modelling equations of well-established models from the literature, such as the Pennes' bioheat transfer equation, and the Henriques and Moritz model to quantify skin damage. Reporting of modelling characteristics and formulation of the computational models is not standardized and there is shortage of implementation of validation procedures, hindering representative conclusions. The lack of validation procedures led to low methodological quality. However, all studies provided strategies and parameters as starting points for future developments in this research area.

The uptake of presymptomatic genetic testing in hereditary breast-ovarian cancer and Lynch syndrome: a systematic review of the literature and implications for clinical practice

Following the identification in a proband of a germline BRCA1/BRCA2 mutation in hereditary breast-ovarian cancer (HBOC) or a DNA mismatch repair gene mutation in Lynch syndrome (LS) he or she will be asked to inform at-risk family members about the option for presymptomatic DNA testing. However, in clinical practice multiple factors may complicate the process of information sharing. We critically evaluated studies on the uptake of presymptomatic genetic testing in both syndromes. A search of relevant MeSH terms and key words in PubMed, Embase and PsycINFO yielded 795 articles published between 2001 and 2017. Thirty of these publications included outcome measures relevant for the current study. Based on information provided by the proband (15 studies) the uptake of presymptomatic genetic testing ranged from 15 to 57% in HBOC, while one study in LS kindreds reported an uptake of 70%. Based on information provided by genetics centres (the remaining 15 studies) the uptake ranged from 21 to 44% in HBOC and from 41 to 94% in LS. However, when genetics centres contacted relatives directly a substantial number of additional family members could be tested. Proband-mediated provision of information to at-risk relatives is a standard procedure in hereditary breast-ovarian cancer and Lynch syndrome. However, the resulting uptake of presymptomatic testing is disappointing-an issue that is now urgent due to the increased use of genetic testing in clinical oncology. We propose that additional strategies should be introduced including the geneticist directly contacting relatives. The outcomes of these strategies should be carefully monitored and evaluated.

Enhanced emissions of brominated flame retardants from indoor sources by direct contact with dust

The emissions of brominated flame retardants (BFRs) from consumer products have been considered the major to the ubiquitous occurrence of contaminants in indoor environments. Direct contact with dust covering the surface of source materials in a real environment could introduce significant uncertainty. This study investigated the effects of dust coverage on the emissions of four BFRs, including 1, 2, 5, 6, 9, and 10-hexabromocyclododecane (HBCD), bis(2-ethyl-1-hexyl) tetrabromophthalate (BEHTBP), tetrabromobisphenol A (TBBPA), and hexabromobenzene (HBBZ), from decorative laminate, cotton sound insulation, PVC floor, and carpet. Direct contact with dust was confirmed to increase the total emissions by 30.8-98.1% compared with the emissions in the non-dust group. The emissions of HBCD, TBBPA, and HBBZ from cotton sound insulation were obviously enhanced by dust with smaller particles but did not linearly increase along with the dust amounts. Thus, these findings have practical implications in that the frequent removal of dust could be important to minimize the exposure risk from indoor emissions of BFRs.

Respiratory infection due to direct contact with rabbit-skin powder contaminated by vaccinia virus

Vaccinia virus infection was diagnosed in five male workers directly exposed to rabbit-skin powder contaminated by vaccinia virus via skin contact and inhalation. Four of the workers had been vaccinated against smallpox. Their clinical symptoms were severe, especially in the lungs; however, all symptoms improved after treatment.

Targeting Transmission Pathways for Emerging Zoonotic Disease Surveillance and Control

We used literature searches and a database of all reported emerging infectious diseases (EIDs) to analyze the most important transmission pathways (e.g., vector-borne, aerosol droplet transmitted) for emerging zoonoses. Our results suggest that at the broad scale, the likelihood of transmission occurring through any one pathway is approximately equal. However, the major transmission pathways for zoonoses differ widely according to the specific underlying drivers of EID events (e.g., land-use change, agricultural intensification). These results can be used to develop better targeting of surveillance for, and more effective control of newly emerged zoonoses in regions under different underlying pressures that drive disease emergence.

Influence of plaque-forming bacterium, Rhodobacteraceae sp. on the growth of Chlorella vulgaris

Experiments were conducted to find out the molecular features, infection process of a special alga plaque-forming microorganism and its potential influence on the biomass of Chlorella vulgaris during the infection process. Direct contact between the algal cell and the bacterium may be the primary steps needed for the bacterium to lyse the alga. Addition of C. vulgaris cells into f/2 medium allowed us obtain the object bacterium. The 16S rRNA gene sequence comparisons results showed that the plaque-forming bacterium kept the closest relationship with Labrenzia aggregata IAM 12614(T) at 98.90%. The existence of the bacterium could influence both the dry weight and lipid content of C. vulgaris. This study demonstrated that direct cell wall disruption of C. vulgaris by the bacterium would be a potentially effective method to utilize the biomass of microalgae.