Designing Biomimetic 3D-Printed Osteochondral Scaffolds for Enhanced Load-Bearing Capacity

Osteoarthritis is a debilitating chronic joint disorder that affects millions of people worldwide. Since palliative and surgical treatments cannot completely regenerate hyaline cartilage within the articulating joint, osteochondral (OC) tissue engineering has been explored to heal OC defects. Utilizing computational simulations and three-dimensional (3D) printing, we aimed to build rationale around fabricating OC scaffolds with enhanced biomechanics. First, computational simulations revealed that interfacial fibrils within a bilayer alter OC scaffold deformation patterns by redirecting load-induced stresses toward the top of the cartilage layer. Principal component analysis revealed that scaffolds with 800 μm long fibrils (scaffolds 8A-8H) possessed optimal biomechanical properties to withstand compression and shear forces. While compression testing indicated that OC scaffolds with 800 μm fibrils did not have greater compressive moduli than other scaffolds, interfacial shear tests indicated that scaffold 8H possessed the greatest shear strength. Lastly, failure analysis demonstrated that yielding or buckling models describe interfacial fibril failure depending on fibril slenderness S. Specifically for scaffolds with packing density n = 6 and n = 8, the yielding failure model fits experimental loads with S < 10, while the buckling model fitted scaffolds with S < 10 slenderness. The research presented provides critical insights into designing 3D printed interfacial scaffolds with refined biomechanics toward improving OC tissue engineering outcomes.

DeepFreeze 3D-biofabrication for Bioengineering and Storage of Stem Cells in Thick and Large-Scale Human Tissue Analogs

3D bioprinting holds great promise for meeting the increasing need for transplantable tissues and organs. However, slow printing, interlayer mixing, and the extended exposure of cells to non-physiological conditions in thick structures still hinder clinical applications. Here the DeepFreeze-3D (DF-3D) procedure and bioink for creating multilayered human-scale tissue mimetics is presented for the first time. The bioink is tailored to support stem cell viability, throughout the rapid freeform DF-3D biofabrication process. While the printer nozzle is warmed to room temperature, each layer solidifies at contact with the stage (-80 °C), or the subsequent layers, ensuring precise separation. After thawing, the encapsulated stem cells remain viable without interlayer mixing or delamination. The composed cell-laden constructs can be cryogenically stored and thawed when needed. Moreover, it is shown that under inductive conditions the stem cells differentiate into bone-like cells and grow for months after thawing, to form large tissue-mimetics in the scale of centimeters. This is important, as this approach allows the generation and storage of tissue mimetics in the size and thickness of human tissues. Therefore, DF-3D biofabrication opens new avenues for generating off-the-shelf human tissue analogs. It further holds the potential for regenerative treatments and for studying tissue pathologies caused by disease, tumor, or trauma.

O49 The use of augmented reality for surgical guidance: an assessment of the human error

Introduction

Microsoft HoloLens® is an augmented-reality headset which is increasingly used for surgical guidance. This headset allows the overlay of patient-specific virtual models obtained from medical images onto the patient’s body surface using automatic marker-based alignment. This can guide surgeons during certain surgical tasks, e.g. determining biopsy needle entry points. This study aims to measure the human error in the localisation of virtual models with the headset and discuss its surgical implications.

Method

59 adults were recruited between the ages of 20–59 years. A 12 cm2 digital marker was displayed on a monitor in 9 different positions, one at a time. This was repeated 3 times, resulting in 27 markers shown to each participant. Once a marker was detected by the headset’s camera, a virtual hexagon was rendered on the headset’s transparent lenses. Participants were tasked to click on the hexagon’s vertices using a mouse. The clicks’ coordinates were recorded by the system and compared to the predicted coordinates. This allowed for the calculation of the vertex localisation error.

Result

The mean vertex localisation error was found to be 5.19 mm (±3.56) with a range from 0.08 to 29.77 mm. There was a significant difference between marker positions as determined by a one-way ANOVA (P &lt; 0.001).

Conclusion

This study suggests that the error in the localisation of virtual models depends on the position of the markers relative to the user wearing the headset. Further research is required to explore whether training can reduce the human error with this headset.

Take-home Message

The range of the human error in localising virtual models via the Microsoft HoloLens® headset is large and may be dependent on the position of the marker relative to the user of the headset. Further research is needed to investigate whether training with the headset can improve human performance.

Superficial parotidectomy versus extracapsular dissection: literature review and search for a gold standard technique

Benign parotid tumours usually present as a slow-growing, asymptomatic mass in the pre-auricular region. Although they are uncommon, surgical excision is the mainstay of treatment due to the risk of malignant transformation in some benign tumours. Surgical techniques have evolved over the years, with superficial parotidectomy and extracapsular dissection being the current procedures of choice. There is currently no gold standard, and it remains unclear which surgical modality is the superior option. A literature review was performed in relation to the relative merits of each technique and to evaluate the reasons underpinning the ongoing debate. A total of 16 papers comparing the main clinical outcomes of the procedures were critically reviewed using the PRISMA protocol. Overall, extracapsular dissection indicated a reduced recurrence rate, facial nerve paralysis, Frey syndrome, and operation time. The superior outcomes following extracapsular dissection could be attributed to the less radical nature of the procedure. However, there were various limitations identified within the review that may have affected the results. Selection bias was the most significant, with patients assigned to the different procedures depending on the tumour size and location. Consequently, the debate continues as to what constitutes the gold standard of care for benign parotid tumours.

Mucosal microbiome in patients with recurrent aphthous stomatitis

Recurrent aphthous stomatitis (RAS) is the most common disease affecting oral mucosae. Etiology is unknown, but several factors have been implicated, all of which influence the composition of microbiota residing on oral mucosae, which in turn modulates immunity and thereby affects disease progression. Although no individual pathogens have been conclusively shown to be causative agents of RAS, imbalanced composition of the oral microbiota may play a key role. In this study, we sought to determine composition profiles of bacterial microbiota in the oral mucosa associated with RAS. Using high-throughput 16S rRNA gene sequencing, we characterized the most abundant bacterial populations residing on healthy and ulcerated mucosae in patients with RAS (recruited using highly stringent criteria) and no associated medical conditions; we also compared these to the bacterial microbiota of healthy controls (HCs). Phylum-level diversity comparisons revealed decreased Firmicutes and increased Proteobacteria in ulcerated sites, as compared with healthy sites in RAS patients, and no differences between RAS patients with healthy sites and HCs. Genus-level analysis demonstrated higher abundance of total Bacteroidales in RAS patients with healthy sites over HCs. Porphyromonadaceae comprising species associated with periodontal disease and Veillonellaceae predominated in ulcerated sites over HCs, while no quantitative differences of these families were observed between healthy sites in RAS patients and HCs. Streptococcaceae comprising species associated with oral health predominated in HCs over ulcerated sites but not in HCs over healthy sites in RAS patients. This study demonstrates that mucosal microbiome changes in patients with idiopathic RAS--namely, increased Bacteroidales species in mucosae of RAS patients not affected by active ulceration. While these changes suggest a microbial role in initiation of RAS, this study does not provide data on causality. Within this limitation, the study contributes to the understanding of the potential role of mucosal microbiome changes in oral mucosal disease.

Acute cervico-facial infection in Scotland 2010: patterns of presentation, patient demographics and recording of systemic involvement

Acute bacterial cervicofacial infection is a common problem that is most often secondary to dental infection. Most cases present as localised abscesses but some may be associated with serious morbidity including scarring, embarrassment of the airway, SIRS (systemic inflammatory response syndrome), and sepsis syndrome. Fourteen oral surgery or maxillofacial surgery units in Scotland took part in a clinical audit of acute infection during two four-week cycles (August and November) in 2010. Information regarding the patients, signs and symptoms, and management was recorded. Training material was distributed between cycles with information on SIRS, sepsis, and the prescription of antibiotics. Overall, 140 patients presented with acute infection. There was an equal sex distribution and ages ranged from 5 to 87 years. There was an association with deprivation and 36% of patients were from the lowest socioeconomic quintile. Most infections were dental (n=120, 86%), and patients presented with pain and swelling (n=120, 86% and n=134, 96%, respectively) Twenty-three patients (16%) met the criteria for SIRS. A further 23 (16%) had at least one positive SIRS marker with incomplete recording of the remaining markers. Twenty-six patients (19%) had no recorded SIRS markers. Cervicofacial infection can be associated with serious morbidity and mortality, which may be better managed if the systemic signs and symptoms of sepsis are recognised and recorded at presentation. This study showed that the recording of signs of sepsis was variable even with training. Further training of junior staff to recognise severe acute bacterial infection may improve management.

Effectiveness of weight management interventions for people with serious mental illness who receive treatment with atypical antipsychotic medications. A literature review

Weight gain associated with treatment with atypical antipsychotic medication has been widely recognized as a risk factor for the development of diabetes and cardiovascular diseases. A systematic search was conducted of major databases and of citations for material about the effectiveness of weight management interventions for people with serious mental illness who receive treatment with atypical antipsychotic medications. Studies were included if the focus was on improvement in weight profile through the application of psychoeducational or exercise and dietary interventions and where outcome measures were reported and presented in recognized values. Out of 221 studies, 19 met the inclusion criteria and after assessment of the quality of the studies, eight were selected for detailed review.

Fostering a culture of engagement: a pilot study of the outcomes of training mental health nurses working in two UK acute admission units in brief solution-focused therapy techniques

It is widely acknowledged that there are major concerns about quality of care, ward atmosphere, the nature of nurse-patient interactions and patient outcomes in UK psychiatric acute admission units. Brief solution-focused therapy (SFT) is an approach which aims to shift the focus of interactions in professional care away from the traditional concentration on an individual's problems and weaknesses towards a more proactive identification of their strengths and positive coping mechanisms. This approach relies on a collaborative engagement with patients, in which the nurse or therapist using simple language aims to help the patient construct a plan to ensure their immediate safety while working to identify, focus on and reinforce their strengths and coping mechanisms in the achievement of identified future goals. This paper reports on a pilot study whose principal objective was to determine whether a short training in brief SFT for psychiatric nurses can produce measurable improvements in nurse-patient interactions in two psychiatric acute admission wards. In this study, 36 nurses undertook a 2-day training course in SFT and were followed up 3 months after training. Positive results were obtained on a number of measures indicating that nurses had acquired knowledge and skills and were applying SFT techniques in their clinical work.

A new method for temporary maxillo-mandibular fixation

We present a novel device which is an alternative to surgical wire for per operative maxillo-mandibular fixation prior to plate placement. It is easy to apply, causes minimal mucosal trauma and can be used in association with elastic chain.

Psychological consequences of maxillofacial trauma: a preliminary study

AIMS

To identify the prevalence of post-traumatic psychological symptoms after maxillofacial trauma and prognostic factors related to poor outcome.

METHODS

Thirty-nine patients were assessed within 10 days of injury and 24 again 4-6 weeks later using five standardised self-report measures on each occasion and a short structured interview at the time of initial contact.

RESULTS

Specific post-traumatic psychological symptoms were present at initial assessment in 21 patients (54%), with 9 (41%) meeting diagnostic criteria for post-traumatic stress disorder at review 4-6 weeks later. Other psychiatric problems, such as anxiety and depression, were identified by the General Health Questionnaire and the Hospital Anxiety and Depression Scale. Characteristics associated with poorer outcome included: a previous history of psychological distress; fear of the unknown, and female sex.

CONCLUSION

These findings highlight the adverse psychological effect of maxillofacial trauma both immediately after the event and 4-6 weeks after injury. Proper assessment of injured patients must include psychological aspects and further research is needed to identify the most appropriate response.

Trauma for all: a pilot study of the subjective experience of physical restraint for mental health inpatients and staff in the UK

Violence and aggression is common in psychiatric inpatient units. Despite the near universal prevalence of restraint, there is very little published research on either the efficacy or the subjective effects of restraint on staff or patients. In this pilot study, semistructured interviews were given to the patients and staff involved in six untoward incidents in which the patient participant had been subject to manual physical restraint. Participants were interviewed as soon as possible after the occurrence of the incidents. The interviews asked the patient and staff participants to identify and discuss the factors that they found helpful and unhelpful during and in the immediate aftermath of these incidents. The incidents generated strong emotions for all concerned. The patients valued staff time and attention but felt that they received too little attention. Both nurses and patients discriminated between permanent and temporary staff. Patients reported feeling upset, distressed and ignored prior to the incidents and isolated and ashamed afterwards. Postincident debriefing was valued by all but was patchy for staff and rarer still for patients. Patients feared the possibility of being restrained. Half of the patients and several staff members reported that the incidents had reawakened distressing memories of previous traumatic events. Further research on the subjective effects of restraint is urgently needed.

HOVIS -- The Hertfordshire/Oxfordshire Violent Incident Study

Violence in psychiatric inpatient units is a major and growing problem. Research interest has primarily focussed on patient characteristics. The role of staff factors and the antecedents of violent incidents has been neglected, despite the fact that staff factors and behaviour may be more readily amenable to change than patient characteristics. The HOVIS study sought to obtain the views of a sample of mental health nurses in current clinical practice about staff-related factors, which they perceive to contribute to, or protect against, the occurrence of violent incidents. A total of 108 nurses working in psychiatric acute admission, intensive care and low secure units, in two NHS Trusts were interviewed using a specially designed semistructured interview schedule. These nurses identified a variety of behaviours, clinical skills, personal characteristics and interpersonal skills that they believe impact on the occurrence of violent incidents. These findings are discussed in relation to their possible training and managerial implications.

The genome sequence of Schizosaccharomyces pombe

We have sequenced and annotated the genome of fission yeast (Schizosaccharomyces pombe), which contains the smallest number of protein-coding genes yet recorded for a eukaryote: 4,824. The centromeres are between 35 and 110 kilobases (kb) and contain related repeats including a highly conserved 1.8-kb element. Regions upstream of genes are longer than in budding yeast (Saccharomyces cerevisiae), possibly reflecting more-extended control regions. Some 43% of the genes contain introns, of which there are 4,730. Fifty genes have significant similarity with human disease genes; half of these are cancer related. We identify highly conserved genes important for eukaryotic cell organization including those required for the cytoskeleton, compartmentation, cell-cycle control, proteolysis, protein phosphorylation and RNA splicing. These genes may have originated with the appearance of eukaryotic life. Few similarly conserved genes that are important for multicellular organization were identified, suggesting that the transition from prokaryotes to eukaryotes required more new genes than did the transition from unicellular to multicellular organization.

Multiple snoRNA gene clusters from Arabidopsis

Small nucleolar RNAs (snoRNAs) are involved in precursor ribosomal RNA (pre-rRNA) processing and rRNA base modification (2'-O-ribose methylation and pseudouridylation). In all eukaryotes, certain snoRNAs (e.g., U3) are transcribed from classical promoters. In vertebrates, the majority are encoded in introns of protein-coding genes, and are released by exonucleolytic cleavage of linearized intron lariats. In contrast, in maize and yeast, nonintronic snoRNA gene clusters are transcribed as polycistronic pre-snoRNA transcripts from which individual snoRNAs are processed. In this article, 43 clusters of snoRNA genes, an intronic snoRNA, and 10 single genes have been identified by cloning and by computer searches, giving a total of 136 snoRNA gene copies of 71 different snoRNA genes. Of these, 31 represent snoRNA genes novel to plants. A cluster of four U14 snoRNA genes and two clusters containing five different snoRNA genes (U31, snoR4, U33, U51, and snoR5) from Arabidopsis have been isolated and characterized. Of these genes, snoR4 is a novel box C/D snoRNA that has the potential to base pair with the 3' end of 5.8S rRNA and snoR5 is a box H/ACA snoRNA gene. In addition, 42 putative sites of 2'-O-ribose methylation in plant 5.8S, 18S, and 25S rRNAs have been mapped by primer extension analysis, including eight sites novel to plant rRNAs. The results clearly show that, in plants, the most common gene organization is polycistronic and that over a third of predicted and mapped methylation sites are novel to plant rRNAs. The variation in this organization among gene clusters highlights mechanisms of snoRNA evolution.

A guided tour: small RNA function in Archaea

In eukaryotes, the C/D box family of small nucleolar (sno)RNAs contain complementary guide regions that are used to direct 2'-O-ribose methylation to specific nucleotide positions within rRNA during the early stages of ribosome biogenesis. Direct cDNA cloning and computational genome searches have revealed homologues of C/D box snoRNAs (called sRNAs) in prokaryotic Archaea that grow at high temperature. The guide sequences within the sRNAs indicate that they are used to direct methylation to nucleotides in both rRNAs and tRNAs. The number of sRNA genes that are detectable within currently sequenced genomes correlates with the optimal growth temperature. We suggest that archaeal sRNAs may have two functions: to guide the deposition of methyl groups at the 2'-O position of ribose, which is an important determinant in RNA structural stability, and to serve as a molecular chaperones to help orchestrate the folding of rRNAs and tRNAs at high temperature.

pH profile of the adsorption of nucleotides onto montmorillonite. I. Selected homoionic clays

The effect of adsorbed ions and pH on the adsorption of several purine and pyrimidine nucleotides on montmorillonite was studied. The cations used to prepare homoionic montmorillonite was Na+, Mn2+, Fe3+, Co2+, Ni+, Cu2+, and Zn2+. The nucleotides studied were 5'-,3'-, and 2'-AMP, and 5'-CMP in the pH range 2 through 12. The results show that preferential adsorption amongst nucleotides and similar molecules is dependent upon pH and the nature of the substituted metal cation in the clay. At neutral pH, it was observed that 5'-AMP was more strongly adsorbed than 2'AMP, 3'-AMP, and 5'-CMP. Cu2+ and Zn2+ clays showed enhanced adsorption of 5'-AMP compared to the other cation clays studied in the pH range 4-8. Below pH 4, the adsorption is attributed to cation and anion exchange adsorption mechanisms: above pH 4, anion exchange may also occur, but the adsorption (when it occurs) likely depends on a complexation mechanism occurring between metal cation in the clay exchange site the biomolecule. It is thus proposed that homoionic clays may have played a significant role in the concentration mechanism of biomonomers in the prebiotic environment, a prerequisite step necessary for the formation of biopolymers in the remaining steps leading to the origin of life.

Transplantation of IL-2-mobilized autologous peripheral blood progenitor cells for adults with acute myelogenous leukemia in first remission

In order to improve leukemia-free survival we evaluated the feasibility and efficacy of autologous transplantation of interleukin-2 (IL-2)-mobilized peripheral blood progenitor cells for adult patients with acute myelogenous leukemia in first remission. Forty-nine consecutive patients (median age 49, range 21-70) with acute myelogenous leukemia in first remission were enrolled on a study of high-dose cytarabine/mitoxantrone consolidation chemotherapy with post-recovery IL-2 used as a method of in vivo purging for the purpose of autologous peripheral blood progenitor cell transplantation. A median of 2.08 x 10(6) CD34+ peripheral blood progenitor cells/kg were infused 1 day after preparative conditioning with 11.25 Gy total body irradiation and cyclophosphamide (120 mg/kg). Forty-one patients received myeloablative chemoradiotherapy followed by the infusion of IL-2-mobilized autologous peripheral blood progenitor cells. The median times to both neutrophil and platelet recovery were 16 days (range, 2-43) and 23 days (8-318+ days), respectively. Twenty-seven patients remain alive with 24 in continued first complete remission. Median remission duration for all eligible patients is 8 months, and actuarial leukemia-free survival is 49+/-15%. The actuarial risk of relapse is 43+/-16%. Toxicity of autologous peripheral blood progenitor cell transplant included treatment-related death in three patients and serious organ toxicity in 12. Advanced age was a negative prognostic factor for leukemia-free survival. Results were compared to an age-matched historical control treated with autologous transplantation of chemotherapy-mobilized progenitor cells; no significant difference in favor of IL-2 mobilization could be demonstrated. Our results demonstrate that autologous transplantation of IL-2-mobilized peripheral blood progenitor cells is feasible in an unselected population of adult patients with acute myelogenous leukemia in first remission with minimal toxicity but no clear evidence of benefit in leukemia-free survival.

Psychiatric Inpatients' Experience of Nursing Observation

1. Nursing observation is a key component of psychiatric inpatient nursing care. 2. Patients' experiences of being observed are strongly influenced by the attitudes and behaviors of the observing nurses. 3. Patients prefer to be observed by nurses they know and who talk to them.

B cells of HIV-1-infected patients bind virions through CD21-complement interactions and transmit infectious virus to activated T cells

The impact of HIV-associated immunopathogenesis on B cells has been largely associated with indirect consequences of viral replication. This study demonstrates that HIV interacts directly with B cells in both lymphoid tissues and peripheral blood. B cells isolated from lymph node and peripheral blood mononuclear cells (PBMCs) of 4 and 23 chronically infected patients, respectively, demonstrated similar capacities to pass virus to activated HIV-negative PBMCs when compared with CD4(+) cells from the same patients. However, in contrast to T cells, virus associated with B cells was surface bound, as shown by its sensitivity to pronase and the staining pattern revealed by in situ amplification of HIV-1 RNA. Cell sorting and ligand displacing approaches established that CD21 was the HIV-binding receptor on B cells, and that this association was mediated through complement-opsonized virus. These B cells were also found to express significantly lower levels of CD21 compared with HIV-negative individuals, suggesting a direct perturbing effect of HIV on B cells. These findings suggest that B cells, although they themselves are not readily infected by HIV, are similar to follicular dendritic cells in their capacity to serve as extracellular reservoirs for HIV-1. Furthermore, B cells possess the added capability of circulating in peripheral blood and migrating through tissues where they can potentially interact with and pass virus to T cells.

Aggressive incidents on a psychiatric intensive care unit

AIM

Although factors related to inpatient aggression have been extensively studied, there is relatively little specific information about violence in intensive care, so the authors decided to conduct their own research into the subject.

METHOD

The authors studied the behaviours of the small number of patients who are involved in most of the aggressive incidents in a psychiatric intensive care unit (PICU) over 15 months.

RESULTS

The study found that female patients were significantly more likely to be involved in aggressive incidents, but that most of these incidents involved self-harm. Patients with a diagnosis of schizophrenia were more likely to display violent behaviour than those from other diagnostic categories. Patients with a personality disorder were more likely to inflict violence against themselves.

CONCLUSION

The authors concluded that all the research on patient violence needs to be standardised to inform practice properly. Nurses need to be aware that relatively few patients are responsible for most of the violent incidents that occur.

Ulceration of the urethral meatus after simultaneous pancreas-kidney transplantation

A 39-year-old male developed painful ulceration of the glans penis following simultaneous pancreas and kidney transplantation for end-stage renal failure complicating insulin-dependent diabetes mellitus. Infection was excluded. Diversion of the pancreatic secretions away from the urinary bladder into the bowel resulted in healing.

A multi-center prospective study of the CD Spinal System in patients with degenerative disc disease

This paper reports on 41 patients available for 24 months' follow-up who were entered into a prospective, multi-center study of the safety and efficacy of using the CD Spinal System (Sofamor Danek) containing pedicle screws and rods to treat adult patients with degenerative disc disease. All of these patients were implanted with only the CD Spinal System in an attempt at fusing four levels or less with autogenous bone graft only. At 24 months the results were compared to literature controls in regard to fusion, pain, function, neurological status, and complications. For function and neurological status, the CD Spinal System results were found to be statistically equal to and for fusion, pain, and complications, found to be statistically better than the noninstrumented literature controls with the same disease condition and demographics.