Transgenic and Diet-Enhanced Silk Production for Reinforced Biomaterials: A Metamaterial Perspective.

Silk fibers, which are protein-based biopolymers produced by spiders and silkworms, are fascinating biomaterials that have been extensively studied for numerous biomedical applications. Silk fibers often have remarkable physical and biological properties that typical synthetic materials do not exhibit. These attributes have prompted a wide variety of silk research, including genetic engineering, biotechnological synthesis, and bioinspired fiber spinning, to produce silk proteins on a large scale and to further enhance their properties. In this review, we describe the basic properties of spider silk and silkworm silk and the important production methods for silk proteins. We discuss recent advances in reinforced silk using silkworm transgenesis and functional additive diets with a focus on biomedical applications. We also explain that reinforced silk has an analogy with metamaterials such that user-designed atypical responses can be engineered beyond what naturally occurring materials offer. These insights into reinforced silk can guide better engineering of superior synthetic biomaterials and lead to discoveries of unexplored biological and medical applications of silk.

Protocol for a Randomised controlled trial to Evaluate the effectiveness and cost benefit of prescribing high dose FLuoride toothpaste in preventing and treating dEntal Caries in high-risk older adulTs (reflect trial).

BACKGROUND: Dental caries in the expanding elderly, predominantly-dentate population is an emerging public health concern. Elderly individuals with heavily restored dentitions represent a clinical challenge and significant financial burden for healthcare systems, especially when their physical and cognitive abilities are in decline. Prescription of higher concentration fluoride toothpaste to prevent caries in older populations is expanding in the UK, significantly increasing costs for the National Health Services (NHS) but the effectiveness and cost benefit of this intervention are uncertain. The Reflect trial will evaluate the effectiveness and cost benefit of General Dental Practitioner (GDP) prescribing of 5000 ppm fluoride toothpaste and usual care compared to usual care alone in individuals 50 years and over with high-risk of caries. METHODS/DESIGN: A pragmatic, open-label, randomised controlled trial involving adults aged 50 years and above attending NHS dental practices identified by their dentist as having high risk of dental caries. Participants will be randomised to prescription of 5000 ppm fluoride toothpaste (frequency, amount and duration decided by GDP) and usual care only. 1200 participants will be recruited from approximately 60 dental practices in England, Scotland and Northern Ireland and followed up for 3 years. The primary outcome will be the proportion of participants receiving any dental treatment due to caries. Secondary outcomes will include coronal and root caries increments measured by independent, blinded examiners, patient reported quality of life measures, and economic outcomes; NHS and patient perspective costs, willingness to pay, net benefit (analysed over the trial follow-up period and modelled lifetime horizon). A parallel qualitative study will investigate GDPs' practises of and beliefs about prescribing the toothpaste and patients' beliefs and experiences of the toothpaste and perceived impacts on their oral health-related behaviours. DISCUSSION: The Reflect trial will provide valuable information to patients, policy makers and clinicians on the costs and benefits of an expensive, but evidence-deficient caries prevention intervention delivered to older adults in general dental practice. TRIAL REGISTRATION: ISRCTN: 2017-002402-13 registered 02/06/2017, first participant recruited 03/05/2018. Ethics Reference No: 17/NE/0329/233335. Funding Body: Health Technology Assessment funding stream of National Institute for Health Research. Funder number: HTA project 16/23/01. Trial Sponsor: Manchester University NHS Foundation Trust, Oxford Road, Manchester, M13 9WL. The Trial was prospectively registered.

Fiberotomy enhances orthodontic tooth movement and diminishes relapse in a rat model.

OBJECTIVES: Accelerated orthodontic tooth movement is triggered by procedures that include mucoperiosteum flap surgery and surgical scarring of cortical bone. Our aim was to test whether fiberotomy by itself will accelerate orthodontic tooth movement and diminish relapse. MATERIALS AND METHODS: In 34 Wistar rats, alveolar bone resorption and molar tooth movement were measured after fiberotomy, apical full-thickness flap without detachment of gingiva from the roots, or no surgery. Orthodontic appliance was installed at time of surgery and activated for 14 days, generating movement of the first maxillary molar buccal and then removed. RESULTS: Percent of sections in which alveolar bone resorption was detected was significantly higher (p < 0.05) after fiberotomy (27%) in comparison with apical flap surgery (12%) or no surgery (6%), after 30 days. Also, at the end of active phase, the molar moved significantly faster (p < 0.01) and twice the distance after fiberotomy (0.54 ± 0.33) in comparison with apical surgery (0.26 ± 0.12) or no surgery (0.3 ± 0.09). Sixteen days after the appliance was removed, only 12% relapse was recorded in the fiberotomy group, while almost total relapse in other two groups. CONCLUSION: We conclude that fiberotomy solely accelerated orthodontic tooth movement and diminished relapse.

The Effect of a Plastic Barrier Drape on Resuscitation Performance and Provider Contamination: A Randomized Controlled Simulation-Based Pilot Trial.

BACKGROUND: Patient barriers to protect health care workers from COVID-19 exposure have been studied for airway management. Few are tested for cardiopulmonary resuscitation (CPR). We sought to determine whether a plastic drape barrier affects resuscitation performance and contamination risks for a simulated cardiopulmonary arrest scenario. METHODS: This pilot trial randomized in-hospital resuscitation teams of 4 to 6 participants to a plastic drape or without a drape in an in situ cardiopulmonary arrest simulation. The mannequin's airway emanated simulated virus particles (GloGerm, Moab, UT), detectable through UV light. Primary outcomes included airway management and CPR quality measures. Secondary outcomes included visible contamination on personal protective equipment (PPE). We used the Non-Technical Skills (NO-TECHS) instrument to measure perceived team performance and the NASA Task Load Index (NASA-TLX) to measure individual workload. Outcome variables were analyzed using an analysis of covariance (ANCOVA) with participant number as a covariate. RESULTS: Seven teams were allocated to the intervention (plastic drape) group and 7 to the control. Intubation and ventilation performance (η 2 = 0.09, P > 0.3) and chest compression quality (η 2 = 0.03-0.19, P > 0.14) were not affected by the plastic drape. However, mean contaminated PPE per person decreased with the drape (2.8 ± 0.3 vs. 3.7 ± 0.3, partial η 2 = 0.29, P = 0.05). No differences in perceived workload nor team performance were noted ( P > 0.09). CONCLUSIONS: In this pilot study, the use of a plastic drape barrier seems not to affect resuscitation performance on simulated cardiopulmonary arrest but decreases health care worker contamination risk. Further implementation trials could characterize the true risk reduction and any effect on resuscitation outcomes.

Graphene-on-silver substrates for sensitive surface plasmon resonance imaging biosensors.

Taking advantage of the high impermeability property of graphene and the sharp surface plasmon resonance (SPR) curve of silver, we numerically demonstrate that SPR imaging biosensors with a graphene-on-silver substrate can be used to achieve the dramatically high sensitivity as well as to prevent silver oxidation. Results of our numerical study show that a silver substrate with a few graphene layers can significantly increase the imaging sensitivity, compared to the conventional gold-film-based SPR imaging biosensor. In particular, single layered graphene deposited on the 60-nm thick silver film amplifies the SPR imaging signal more than three times. Therefore, the proposed SPR substrate could potentially open a new possibility of SPR imaging detection for sensitive and high-throughput assessment of multiple biomolecular interactions.

Random laser spectroscopy for nanoscale perturbation sensing.

We report a spectroscopic method using coherent random lasers for a simple, yet nanoscale, sensing approach. Unique spectral properties of coherent random laser emission can be detectably altered when introducing nanoscale perturbations to a simple nanocomposite film that consists of dielectric nanospheres and laser-dye-doped polymer to serve as a transducer. Random lasing action provides a means to amplify subtle perturbations to readily detectable spectral shifts in multiple discrete emission peaks. Owing to several advantages, such as large-area detection, narrow and multiple emission peaks, straightforward detection, and simple fabrication, random laser spectroscopy has the potential for ultrasensitive, yet simple, biosensors in various applications.

Environmental surveillance for Laribacter hongkongensis, a diarrhoeal pathogen discovered in Hong Kong.

1. Laribacter hongkongensis was isolated from the midguts and hindguts of 86 (24%) of 360 freshwater fish from retail markets, including grass carp (60%), bighead carp (53%), mud carp (25%), and large-mouth bass (5%). 2. This study is the first to demonstrate the presence of L hongkongensis in natural water environments, with the bacterium being isolated from the waters of six reservoirs, with higher recovery rates in summer and during days of higher water and ambient temperatures. 3. Molecular typing using pulsed field gel electrophoresis revealed a heterogeneous population of L hongkongensis in both the freshwater fish and drinking water reservoir isolates, suggesting that the bacterium is endemic in our freshwater environments. 4. Since freshwater fish are common food items for our population, the general public should be educated on the proper preparation and thorough cooking of freshwater fish before consumption to avoid L hongkongensis-associated gastroenteritis. 5. Although it is unlikely that treated drinking water is a significant source of L hongkongensis-associated gastroenteritis, it is important to be aware of the possibility of other contaminated water as a source of human infection.

A call to greater inclusion of gerodontology in the dental curriculum: A narrative review.

AIM: This literature review explores the need for greater prominence of gerodontology in the undergraduate dental curriculum, focusing on the significance of gerodontology for dental students on clinical placements. BACKGROUND: As Australia's population ages the number of dentate older people is increasing. An assessment of the dental profession's preparedness, including that of future providers, is needed to ensure that this public health issue is addressed. METHODS: A database search was performed in MEDLINE (Ovid), CINAHL and JCU OneSearch. Of the 41 articles identified, 31 were selected for review using a narrative approach. DISCUSSION: Of the 31 articles reviewed, 12 were Australian, 9 North American and 5 European. Five overarching themes were identified, including preparedness for residential aged care facilities; barriers to oral health services provision; attitudes to aged care; gerodontology as part of a dental school curriculum and service-based learning. CONCLUSION: There are differences in the gerodontology curricula of dental schools, with a wide variation of clinical exposure to older patients. There is evidence that exposure to gerodontology curriculum prior to treating older people may help dental students feel more prepared for managing patients in aged care. The current marginal status of gerodontology in dental school curricula is in need of review.

Exploring the feasibility of general health promotion in UK dental primary care: ENGAGE in Scotland.

Introduction Despite UK dental guidance recommending opportunistic health promotion, it's rare for GDPs to discuss more than oral hygiene with their patients. The ENGAGE intervention incorporates UK guidance and evidence-based behaviour change techniques to motivate patients to make lifestyle changes (reduce smoking, alcohol consumption and/or improve diet). It was designed to take less than five minutes and be delivered during a routine dental check-up, and includes a take-home patient handout signposting to free NHS lifestyle counselling helpline services.Aims To determine the feasibility (patient and GDP acceptance) of implementing ENGAGE in Scottish dental primary care. The overall aim is to examine feasibility UK-wide before testing its effectiveness for influencing patient outcomes in a multi-centre UK trial.Methods Study 1: patient survey: N = 1000 adults from all health boards in Scotland were randomly selected from an NHS data base of medical patients and emailed the study invitation and link to an online questionnaire. Study 2: GDP workshop, audit, survey: N = 50 GDPs across Scotland were invited to participate in the training workshop (limited to the first 20 applicants), implement the intervention with their next 20 adult patients in for a check-up, audit their experience, then complete an online questionnaire.Results Study 1: 200 people completed the survey (52% male; 37% were 55 years or younger; 90% had visited their dentist in the previous 12 months). Less than (<) 15% were asked about their smoking, alcohol intake and/or diet when they last visited their dentist for a check-up; <10% would be embarrassed/offended if their dentist or dental hygienist asked them lifestyle questions during a dental check-up; more than (>) 70% would be reassured by the professionalism of their dentist or dental hygienist if they were asked; <4% would be embarrassed/offended if given a leaflet with NHS helpline information by their dentist. Study 2: N = 18 GDPs from nine out of 14 NHS regional health boards in Scotland delivered the ENGAGE intervention to 335 patients (averaging 18 patients each). N = 17/18 participants agreed that this intervention could be delivered during a check-up, was an improvement on what they currently did and thought that it may make a difference to what their patients thought, felt, and/or did about reducing health risk.Conclusion The ENGAGE intervention is feasible to implement in Scottish dental primary care. Comments from patient and GDP participants will inform its development and further feasibility studies set in other UK regions.

Spectroscopic translation of cell-material interactions.

The characterization of cellular interactions with a biomaterial surface is important to the development of novel biomaterials. Traditional methods used to characterize processes such as cellular adhesion and differentiation on biomaterials can be time consuming, and destructive, and are not amenable to quantitative assessment in situ. As the development of novel biomaterials shifts towards small-scale, combinatorial, and high throughput approaches, new techniques will be required to rapidly screen and characterize cell/biomaterial interactions. Towards this goal, we assessed the feasibility of using 4-dimensional elastic light-scattering fingerprinting (4D-ELF) to describe the differentiation of human aortic smooth muscle cells (HASMCs), as well as the adhesion, and apoptotic processes of human aortic endothelial cells (HAECs), in a quantitative and non-perturbing manner. HASMC and HAEC were cultured under conditions to induce cell differentiation, attachment, and apoptosis which were evaluated via immunohistochemistry, microscopy, biochemistry, and 4D-ELF. The results show that 4D-ELF detected changes in the size distributions of subcellular organelles and structures that were associated with these specific cellular processes. 4D-ELF is a novel way to assess cell phenotype, strength of adhesion, and the onset of apoptosis on a biomaterial surface and could potentially be used as a rapid and quantitative screening tool to provide a more in-depth understanding of cell/biomaterial interactions.

Chemoprevention of colon carcinogenesis by polyethylene glycol: suppression of epithelial proliferation via modulation of SNAIL/beta-catenin signaling.

Polyethylene glycol (PEG) is one of the most potent chemopreventive agents against colorectal cancer; however, the mechanisms remain largely unexplored. In this study, we assessed the ability of PEG to target cyclin D1-beta-catenin-mediated hyperproliferation in the azoxymethane-treated rat model and the human colorectal cancer cell line, HT-29. Azoxymethane-treated rats were randomized to AIN-76A diet alone or supplemented with 5% PEG-8000. After 30 weeks, animals were euthanized and biopsies of aberrant crypt foci and uninvolved crypts were subjected to immunohistochemical and immunoblot analyses. PEG markedly suppressed both early and late markers of azoxymethane-induced colon carcinogenesis (fractal dimension by 80%, aberrant crypt foci by 64%, and tumors by 74%). In both azoxymethane-treated rats and HT-29 cells treated with 5% PEG-3350 for 24 hours, PEG decreased proliferation (45% and 52%, respectively) and cyclin D1 (78% and 56%, respectively). Because beta-catenin is the major regulator of cyclin D1 in colorectal cancer, we used the T-cell factor (Tcf)-TOPFLASH reporter assay to show that PEG markedly inhibited beta-catenin transcriptional activity. PEG did not alter total beta-catenin expression but rather its nuclear localization, leading us to assess E-cadherin expression (a major determinant of beta-catenin subcellular localization), which was increased by 73% and 71% in the azoxymethane-rat and HT-29 cells, respectively. We therefore investigated the effect of PEG treatment on levels of the negative regulator of E-cadherin, SNAIL, and observed a 50% and 75% decrease, respectively. In conclusion, we show, for the first time, a molecular mechanism through which PEG imparts its antiproliferative and hence profound chemopreventive effect.

The influence of AVPR1A genotype on individual differences in behaviors during a mirror self-recognition task in chimpanzees (Pan troglodytes).

The mark/rouge test has been used to assess mirror self-recognition (MSR) in many species. Despite consistent evidence of MSR in great apes, genetic or non-genetic factors may account for the individual differences in behavioral responses that have been reported. We examined whether vasopressin receptor gene (AVPR1A) polymorphisms are associated with MSR-related behaviors in chimpanzees since vasopressin has been implicated in the development and evolution of complex social relations and cognition and chimpanzees are polymorphic for the presence of the RS3-containing DupB region. We compared a sample of DupB+/- and DupB-/- chimpanzees on a mark test to assess its role on social behavior toward a mirror. Chimpanzees were administered two, 10-min sessions where frequencies of mirror-guided self-directed behaviors, contingent actions and other social behaviors were recorded. Approximately one-third showed evidence of MSR and these individuals exhibited more mirror-guided self-exploratory behaviors and mouth contingent actions than chimpanzees not classified as passers. Moreover, DupB+/- males exhibited more scratching and agonistic behaviors than other male and female cohorts. Our findings support previous studies demonstrating individual differences in MSR abilities in chimpanzees and suggest that AVPR1A partly explains individual differences in MSR by influencing the behavioral reactions of chimpanzees in front of a mirror.

Current practice and factors influencing the provision of periodontal healthcare in primary dental care in Scotland: an explorative study.

AIMS: To understand current practice and the beliefs of dentists and hygienists towards factors which may influence the management of patients with periodontal diseases in primary dental care in Scotland. To inform the scope of a guidance publication and the future development of diagnostic analyses tools. METHODS: A qualitative approach of semi-structured telephone interviews with a randomly selected sample of dentists and hygienists was used. Interviews continued until saturation was reached and were audio-recorded and transcribed verbatim. The data were analysed using the method of framework analysis. To increase the participation of hygienists the topic guide was adapted into a self-reporting questionnaire and posted to all hygienists in Scotland. RESULTS: Eighteen dentists and three hygienists were interviewed. Key themes identified were extent of control over working environment, capabilities to treat appropriately and changing patients' oral hygiene behaviour. Factors which facilitated the management of patients with periodontal diseases were 'access to a hygienist' and 'beliefs about capabilities', while 'routine and habit', 'motivation of patients' and 'time and money' were perceived as barriers. Some evidence of variation in treatment provision and of varying levels of confidence among practitioners about treating more advanced periodontal conditions was identified. Two hundred and thirty-seven hygienists returned the postal questionnaire. Agreement was found with the views of the interviewed hygienists on beliefs about capabilities and routine record-keeping. CONCLUSION: To improve the periodontal health of patients requires consideration of both extrinsic and intrinsic factors present in primary dental care. Practitioners would find having guidance on managing patients with basic periodontal examinations of three and four, referral criteria to secondary care, record-keeping and techniques to change patients' oral hygiene behaviour particularly useful. Applying the evaluative framework pre-publication indicated where knowledge translation interventions may be required in the future.

Is further intervention required to translate caries prevention and management recommendations into practice?

AIMS: In April 2010, the Scottish Dental Clinical Effectiveness Programme (SDCEP) published guidance on the Prevention and management of dental caries in children. The aims of this study were to determine if further intervention is required to translate the SDCEP guidance recommendations into practice and to identify salient beliefs associated with recommended practice. METHODS: Two postal surveys circulated to two independent random samples of dentists working in general dental practices in Scotland, before and after the publication of the guidance. The questionnaire items assessed current practice and beliefs relating to the prevention and management of dental caries in children. RESULTS: Response rates of 40% (n = 87) and 45% (n = 131) were achieved. The results highlight a gap between current practice and recommended practice. The majority of dentists do not 'always' perform recommended behaviours and many are following treatment strategies specifically not recommended in the guidance. More positive attitude, greater capability and motivation were significantly associated with performing more guidance recommended risk assessment and prevention behaviours. CONCLUSIONS: These findings highlight the need for further intervention to translate the SDCEP guidance recommendations into practice and give initial insight into the salient beliefs that may serve as targets for future interventions.

Photodynamic therapy of pigmented choroidal melanomas using a liposomal preparation of benzoporphyrin derivative.

OBJECTIVE: To evaluate the effectiveness of photodynamic therapy of pigmented choroidal melanoma using a liposomal preparation of benzoporphyrin derivative monoacid (BPD), verteporfin. DESIGN: Pigmented choroidal melanomas were established in 25 New Zealand albino rabbit eyes. The animals were treated with daily injections of cyclosporine, and tumor growth was monitored with funduscopic examination and ultrasonography. Fifteen minutes after intravenous injection of BPD (2 mg/kg), the tumors were irradiated at 692 nm through an argon-pumped dye laser with the delivered fluence ranging between 40 and 150 J/cm2. Control animals were treated with light only, photosensitizer only, or observation only. Tumor growth was monitored by indirect ophthalmoscopy, fundus photography, fluorescein angiography, and ultrasonography. Histologic examination was performed. RESULTS: Eighteen tumor-bearing rabbits were treated with light and BPD; 16 were followed up for 1 month, and two were killed immediately for histologic examination. Tumors regressed in all eyes treated with 60 J/cm2 or more. With fluence of 40 J/cm2, tumor regrowth was observed in one animal within 10 days of treatment. In the three control groups, all animals showed continuous tumor growth. Histologic examination of the eyes treated with photosensitizer and light immediately after treatment showed prominent vascular occlusion throughout the full thickness of the tumor. One month after treatment, tumor necrosis and infiltration of mononuclear cells and pigment-laden macrophages were the predominant findings. CONCLUSIONS: Photodynamic therapy with BPD may have a role in the treatment of pigmented choroidal melanomas.

Digital angiography of experimental choroidal melanomas using benzoporphyrin derivative.

PURPOSE: To examine benzoporphyrin derivative angiography as a modality for studying photosensitizer biodistribution in experimental choroidal melanomas. METHODS: A liposomal preparation of benzoporphyrin derivative was used in this study. Digital benzoporphyrin derivative angiograms were performed in 10 rabbits (six for experimental choroidal melanomas, two for normal choroids, and two for irides) using a Topcon ImageNet H1024 digital imaging system, a Kodak Megaplus video camera, and a Topcon TRC-50-VT fundus camera. Only one eye from each rabbit was used. Filters specifically designed for benzoporphyrin derivative (peak absorption at 580 nm and peak emission at 695 nm) were used. Benzoporphyrin derivative (1 mg/kg) was injected into an ear vein while images of tumor, normal choroid, or iris were being obtained. Follow-up images were obtained during the first 3 hours and at 24 hours after injection. Fluorescence microscopy was performed in all 10 rabbits using 1 mg/kg of benzoporphyrin derivative. Tumor-bearing eyes were enucleated at the same time points that angiograms were performed, and the two sets of results were compared for maximum dye accumulation. RESULTS: Digital angiography demonstrated that maximal benzoporphyrin derivative fluorescence occurred in tumors 15 to 45 minutes after injection. Fluorescence photometry corroborated these results. CONCLUSION: Photosensitizer angiography is a valid modality for determining the optimum treatment time for photodynamic therapy.

Episodic factitious gingival injury secondary to topical anesthesia. A case report.

The contribution of topical anesthesia to the incidence of severe factitious gingival injury in an adult patient is reported. A brief review of the literature is also presented.

Shaping ability of three ProFile rotary instrumentation techniques in simulated resin root canals.

The aim of this study was to compare the shaping ability of three ProFile rotary instrumentation techniques and a conventional step-back method in simulated root canals. Prevalence of canal aberrations, change in working length, and preparation time were measured. A total of 48 composite images were made from pre- and postcanal scanned images using Corel Photopaint 8.0 and then the amount of coronal substance the instruments removed was also calculated two-dimensionally on digitized images with the Brain C software to compare the enlarging efficiency. There were no significant differences between the three rotary groups in preparation time, change in working length, and the incidence of aberrations (p > 0.05). The amount of coronal substance the instruments removed in the ProFile .04 taper group was significantly smaller than the other three groups (p < 0.05).

The use of cueing and positive practice in the treatment of tongue thrust swallowing.

Tongue thrust or reverse swallowing refers to the condition in which portions of the tongue rest or press against the teeth. In very severe cases the result can be dental malocclusion and/or speech difficulties. The present investigation evaluates the efficacy of cueing and positive practice in increasing the frequency of correct tongue position using a modified single subject withdrawal design with a 21 year old college student. The data indicate that the frequency of correct tongue positioning increased with the introduction of treatment. Follow-up data obtained 30 months post-treatment indicate that positive effects were being maintained.

High tolerance of broilers to vomitoxin from corn infected with Fusarium graminearum.

Corn purposely infected with Fusarium graminearum was found to contain 800 to 900 mg vomitoxin/kg. Contaminated corn was substituted for control corn at 0, 6, 12, 18, and 24% in a corn-soybean meal ration. Broiler cockerels were given each experimental diet from 6 to 11 days of age; then sample groups were necropsied. Remaining birds were subsequently offered commercial starter for 2 days and sample groups again necropsied. Growth and diet consumption were not significantly reduced until contaminated corn exceeded 12% of the ration (116 mg vomitoxin/kg). Alertness, coordination, and feathering appeared normal regardless of treatment. Birds that received contaminated corn exhibited plaques in the mouth and gizzard erosions proportional to the level of substitution. All lesions were generally restricted to the epithelial layer and no liver or kidney involvement could be demonstrated. A short return to uncontaminated feed eliminated most lesions. Fowl appear to be considerably more tolerant of vomitoxin than swine.