Molecular architecture of the ciliary tip revealed by cryo-electron tomography.

Cilia are essential organelles that protrude from the cell body. Cilia are made of a microtubule-based structure called the axoneme. In most types of cilia, the ciliary tip is distinct from the rest of the cilium. Here, we used cryo-electron tomography and subtomogram averaging to obtain the structure of the ciliary tip of the ciliate Tetrahymena thermophila. We show the microtubules in the tip are highly cross-linked with each other and stabilised by luminal proteins, plugs and cap proteins at the plus ends. In the tip region, the central pair lacks the typical projections and twists significantly. By analysing cells lacking a ciliary tip-enriched protein CEP104/FAP256 by cryo-electron tomography and proteomics, we discovered candidates for the central pair cap complex and explain potential functions of CEP104/FAP256. These data provide new insights into the function of the ciliary tip and inform about the mechanisms of ciliary assembly and length regulation.

Diet and irritable bowel syndrome: an update from a UK consensus meeting.

There has been a renewed interest in the role of dietary therapies to manage irritable bowel syndrome (IBS), with diet high on the agenda for patients. Currently, interest has focussed on the use of traditional dietary advice (TDA), a gluten-free diet (GFD) and the low FODMAP diet (LFD). A consensus meeting was held to assess the role of these dietary therapies in IBS, in Sheffield, United Kingdom.Evidence for TDA is from case control studies and clinical experience. Randomised controlled trials (RCT) have demonstrated the benefit of soluble fibre in IBS. No studies have assessed TDA in comparison to a habitual or sham diet. There have been a number of RCTs demonstrating the efficacy of a GFD at short-term follow-up, with a lack of long-term outcomes. Whilst gluten may lead to symptom generation in IBS, other components of wheat may also play an important role, with recent interest in the role of fructans, wheat germ agglutinins, as well as alpha amylase trypsin inhibitors. There is good evidence for the use of a LFD at short-term follow-up, with emerging evidence demonstrating its efficacy at long-term follow-up. There is overlap between the LFD and GFD with IBS patients self-initiating gluten or wheat reduction as part of their LFD. Currently, there is a lack of evidence to suggest superiority of one diet over another, although TDA is more acceptable to patients.In view of this evidence, our consensus group recommends that dietary therapies for IBS should be offered by dietitians who first assess dietary triggers and then tailor the intervention according to patient choice. Given the lack of dietetic services, novel approaches such as employing group clinics and online webinars may maximise capacity and accessibility for patients. Further research is also required to assess the comparative efficacy of dietary therapies to other management strategies available to manage IBS.

Activity Levels and Outcomes of a Standalone Regional Paediatric High Dependency Unit.

Aim The Paediatric High Dependency Unit (PHDU) at University Hospital Limerick (UHL) operates as the only standalone unit outside of Dublin centres. The aim of this study was to describe a regional PHDU population, compare outcomes with international standards (PICANet) and ensure adequate clinical governance. Methods This is a retrospective analysis of 126 admission records from January - December 2019. Results There were 126 admissions to PHDU in 2019, of which respiratory (n=81, 64.3%) and neurological (n=23, 18.3%) subgroups represented the largest populations. Median length of stay was two days with mean age of admission 3.97 ± 4.5 years and slightly more male admissions (56%). Of the total, 65% required oxygen, 32.1% needed CPAP directly and 38% commenced high-flow, of whom 29% transitioned to CPAP. Transfer for tertiary care was required in 10.3%, of whom 7.9% needed PICU. Conclusion The data show UHL PHDU to have a patient population reflecting international trends as well as producing satisfactory patient outcomes. With a low rate of transfer for tertiary care and given that 15 other paediatric units exist in the Republic of Ireland outside Dublin, development of regional PHDU capacity would provide great opportunity to decrease strain on PICU bed capacity, particularly during busy Winter months.

Anaesthesia management of a child with aromatic L-amino acid decarboxylase deficiency.

Aromatic L-amino acid decarboxylase deficiency is an autosomal recessive disorder that results in a lack of neurotransmitters including serotonin, dopamine, noradrenaline and adrenaline. It is characterised by developmental delay, severe hypotonia and autonomic disturbance. In patients with this condition, catecholamine deficiency and autonomic dysfunction, resulting in haemodynamic instability under anaesthesia is a primary concern. There is increased sensitivity to exogenous catecholamines and indirect acting agents, such as ephedrine, are ineffective. Hypoglycaemia, difficult airway status and drug interactions such as with monoamine oxidase inhibitors are also of concern, and these patients are at risk of dystonic crises peri-operatively. A 6-year-old boy with aromatic L-amino acid decarboxylase deficiency presented for gastrointestinal endoscopy. Following multidisciplinary discussion, we elected to provide general anaesthesia with a propofol target-controlled infusion, which proceeded without incident. In this report, we describe the precautions taken in this case, and discuss the provision of general anaesthesia for children with rare neurometabolic disorders.

In vitro effects of macrophages on orthopaedic implant alloys and local release of metallic alloy components.

AIMS: This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys. METHODS: Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment. RESULTS: On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant increase in aluminum (p < 0.001) among all groups compared with medium only. CONCLUSION: These results indicated that macrophages were able to attach to and affect the oxide surface of stainless steel and titanium alloy discs. Cite this article: Bone Joint J 2020;102-B(7 Supple B):116-121.

Characterisation and evaluation of the regenerative capacity of Stro-4+ enriched bone marrow mesenchymal stromal cells using bovine extracellular matrix hydrogel and a novel biocompatible melt electro-written medical-grade polycaprolactone scaffold.

Many skeletal tissue regenerative strategies centre around the multifunctional properties of bone marrow derived stromal cells (BMSC) or mesenchymal stem/stromal cells (MSC)/bone marrow derived skeletal stem cells (SSC). Specific identification of these particular stem cells has been inconclusive. However, enriching these heterogeneous bone marrow cell populations with characterised skeletal progenitor markers has been a contributing factor in successful skeletal bone regeneration and repair strategies. In the current studies we have isolated, characterised and enriched ovine bone marrow mesenchymal stromal cells (oBMSCs) using a specific antibody, Stro-4, examined their multipotential differentiation capacity and, in translational studies combined Stro-4+ oBMSCs with a bovine extracellular matrix (bECM) hydrogel and a biocompatible melt electro-written medical-grade polycaprolactone scaffold, and tested their bone regenerative capacity in a small in vivo, highly vascularised, chick chorioallantoic membrane (CAM) model and a preclinical, critical-sized ovine segmental tibial defect model. Proliferation rates and CFU-F formation were similar between unselected and Stro-4+ oBMSCs. Col1A1, Col2A1, mSOX-9, PPARG gene expression were upregulated in respective osteogenic, chondrogenic and adipogenic culture conditions compared to basal conditions with no significant difference between Stro-4+ and unselected oBMSCs. In contrast, proteoglycan expression, alkaline phosphatase activity and adipogenesis were significantly upregulated in the Stro-4+ cells. Furthermore, with extended cultures, the oBMSCs had a predisposition to maintain a strong chondrogenic phenotype. In the CAM model Stro-4+ oBMSCs/bECM hydrogel was able to induce bone formation at a femur fracture site compared to bECM hydrogel and control blank defect alone. Translational studies in a critical-sized ovine tibial defect showed autograft samples contained significantly more bone, (4250.63 mm3, SD = 1485.57) than blank (1045.29 mm3, SD = 219.68) ECM-hydrogel (1152.58 mm3, SD = 191.95) and Stro-4+/ECM-hydrogel (1127.95 mm3, SD = 166.44) groups. Stro-4+ oBMSCs demonstrated a potential to aid bone repair in vitro and in a small in vivo bone defect model using select scaffolds. However, critically, translation to a large related preclinical model demonstrated the complexities of bringing small scale reported stem-cell material therapies to a clinically relevant model and thus facilitate progression to the clinic.

Long term outcomes of abdominal wall reconstruction using open component separation and biologic mesh in the liver, kidney, and small bowel transplant population.

PURPOSE: The aim of this study is to critically examine the multidisciplinary approach to abdominal wall reconstruction (AWR) in the solid organ transplant (SOT) population at our institution, MedStar Georgetown University Hospital, using a modified component separation technique (CST). METHODS: A retrospective review of AWR utilizing modified open CST with biologic mesh in SOT patients was performed from January 2010 to June 2018. Patient demographics, comorbidities, operative details, complications, and outcomes were recorded. Descriptive statistics, logistic and linear regression analyses were performed to appraise outcomes. RESULTS: Thirty-five patients were included; mean age was 53 years. Patient demographics and comorbidities were: 82.9% male, 45.7% history of tobacco use, and 28.6% diabetes. Fifty-one percent had undergone prior hernia repair. Transplant types were: kidney (9), liver (16), liver/kidney (1), small bowel (7), multivisceral (2). All were on an immunosuppressive regimen at time of surgery; 22.9% included steroids. Average defect size was 361 cm2. Additional soft tissue procedures were performed in 65.7% (n = 23) of patients. Median time to healing was 29.0 days. Complication rate was 31.4% (n = 11); six patients required reoperation within 90 days. Recurrence rate was 5.7% (n = 2) at mean of follow up of 3.0 years. Additional soft tissue procedures were statistically significant for healing time (p = 0.037). Steroid use was statistically significant for reoperation within 90 days (OR = 12.500; 95% CI 1.694-92.250); however, steroid use was not significant after correction for confounders. CONCLUSION: Modified open CST with biologic mesh is a safe, efficacious approach to complex AWR in the SOT population with recurrence rates comparable to the general population.

Impact of shear rate pattern on post-occlusive near-infrared spectroscopy microvascular reactivity.

The primary aim of the present study was to determine the impact of acute changes in shear rate patterns, in particular retrograde shear rate, on microvascular function in 15 healthy, young men and women as determined via the post-occlusive near-infrared spectroscopy (NIRS) microvascular reactivity response. Microvascular reactivity, via NIRS-derived measurements of post-occlusion tissue saturation index (TSI%) and total microvascular hemoglobin+myoglobin concentration ([Hb]total), were assessed in each participant before and immediately after exposure to a 30min retrograde shear treatment. Retrograde shear was achieved via a blood pressure cuff placed below the knee inflated to 75mmHg. One leg was exposed to the retrograde shear (Treatment leg) and the contralateral leg served as a non-treatment control. In the Treatment leg, significant increases in retrograde shear rate occurred during the retrograde intervention. Following the intervention, the area under the TSI% post-occlusion response curve, which represents the total microvascular reactivity response, and the absolute peak TSI% response were significantly increased compared to pre-intervention in the Treatment leg, but not the Control leg. The absolute peak [Hb]total response was significantly increased post-intervention in both legs. These results are in contrast to our hypothesis that 75mmHg cuff inflation, designed to increase retrograde shear rate in the femoral artery would negatively affect post-occlusive microvascular reactivity. These data suggest that the current method of increasing retrograde shear rate in the intact human does not adversely impact NIRS derived measurements of microvascular reactivity.

Small Talk: Identifying communication problems in maltreated children.

Development of speech and language is rapid in early years, yet if developmental problems in speech and language are not addressed they are likely to continue and impact negatively on a child's overall development and their life trajectory. Children who have experienced abuse and or neglect are particularly vulnerable. The aim of this study was to develop a tool to assist in identifying a child's need for assessment by a speech pathologist so that there could be early identification of problems. A culturally sensitive tool was developed to be completed by the child's carer included questions on language, speech and hearing, voice, fluency, understanding sentences, vocabulary and expression. Sixty-five children aged between 4 and 8 years, who had experienced abuse and/or neglect participated in the study. Fourteen percent were Aboriginal. A speech pathologist undertook an assessment for each child and the results were compared with the information on the Small Talk tool. The Tool was found to be high in sensitivity but low in specificity, requiring further refinement. However, it has the potential to assist non speech pathologists to identify a child's need for speech and language assessment with the findings identifying the Tool as promising practice.

Deprescribing antihyperglycemic agents in older persons: evidence-based clinical practice guideline

OBJECTIVE: To develop an evidence-based guideline to help clinicians make decisions about when and how to safely taper, stop, or switch antihyperglycemic agents in older adults. METHODS: We focused on the highest level of evidence available and sought input from primary care professionals in guideline development, review, and endorsement processes. Seven clinicians (2 family physicians, 3 pharmacists, 1 nurse practitioner, and 1 endocrinologist) and a methodologist comprised the overall team; members disclosed conflicts of interest. We used a rigorous process, including the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach, for guideline development. We conducted a systematic review to assess evidence for the benefits and harms of deprescribing antihyperglycemic agents. We performed a review of reviews of the harms of continued antihyperglycemic medication use, and narrative syntheses of patient preferences and resource implications. We used these syntheses and GRADE quality-of-evidence ratings to generate recommendations. The team refined guideline content and recommendation wording through consensus and synthesized clinical considerations to address common front-line clinician questions. The draft guideline was distributed to clinicians and stakeholders for review and revisions were made at each stage. A decision-support algorithm was developed to accompany the guideline. RECOMMENDATIONS: We recommend deprescribing antihyperglycemic medications known to contribute to hypoglycemia in older adults at risk or in situations where antihyperglycemic medications might be causing other adverse effects, and individualizing targets and deprescribing accordingly for those who are frail, have dementia, or have a limited life expectancy. CONCLUSION: This guideline provides practical recommendations for making decisions about deprescribing antihyperglycemic agents. Recommendations are meant to assist with, not dictate, decision making in conjunction with patients.

Elucidating the Mechanism(s) Underlying Antipsychotic and Antidepressant-Mediated Fractures.

Mood spectrum disorders and medications used to treat these disorders, such as atypical antipsychotic drugs (AA), are associated with metabolic and endocrine side effects including obesity, dyslipidemia, hyperglycemia and increased risk of fractures. Antidepressant medications, including selective serotonin reuptake inhibitors (SSRI), have also been reported to increase fracture risk in some patients. The pharmacology underlying the increased risk of fractures is currently unknown. Possible mechanisms include alternations in dopaminergic and/or serotonergic signaling pathways. As these medications distribute to the bone marrow as well as to the brain, it is possible that drug-induced fractures are due to both centrally mediated effects as well as direct effects on bone turnover. Given the growing patient population that is prescribed these medications for both on- and off-label indications, understanding the level of risk and the mechanisms underlying drug-induced fractures is important for informing both prescribing and patient monitoring practices.

Oxidative stress in major depressive and anxiety disorders, and the association with antidepressant use; results from a large adult cohort.

BACKGROUND: Oxidative stress has been implicated in the pathophysiology of major depressive disorder (MDD) and anxiety disorders and may be influenced by antidepressant use. This study investigated the association of oxidative stress, measured by plasma levels of F2-isoprostanes and 8-hydroxy-2'-deoxyguanosine (8-OHdG) reflecting oxidative lipid and DNA damage respectively, with MDD, anxiety disorders and antidepressant use in a large cohort. METHOD: Data was derived from the Netherlands Study of Depression and Anxiety including patients with current (N = 1619) or remitted (N = 610) MDD and/or anxiety disorder(s) (of which N = 704 antidepressant users) and 612 controls. Diagnoses were established with the Composite International Diagnostic Interview. Plasma 8-OHdG and F2-isoprostanes were measured using LC-MS/MS. ANCOVA was performed adjusted for sampling, sociodemographic, health and lifestyle variables. RESULTS: F2-isoprostanes did not differ between controls and patients, or by antidepressant use. Patients with current disorders had lower 8-OHdG (mean 42.1 pmol/l, 95% CI 40.4-43.8) compared to controls (45.0 pmol/l, 95% CI 42.9-47.2; p < 0.001) after adjustment for sampling, sociodemographics and lifestyle, but these differences disappeared after further adjustment for antidepressant use (p = 0.562). Antidepressant users had lower 8-OHdG levels (38.2 pmol/l, 95% CI 36.5-39.9) compared to controls (44.9 pmol/l, 95% CI 43.2-46.6; Cohen's d = 0.21, p < 0.001). Results for 8-OHdG were comparable across disorders (MDD and/or anxiety disorders), and all antidepressant types (SSRIs, TCAs, other antidepressants). CONCLUSION: Contrary to previous findings this large-scale study found no increased oxidative stress in MDD and anxiety disorders. Antidepressant use was associated with lower oxidative DNA damage, suggesting antidepressants may have antioxidant effects.

Long term effects of gestational hypertension and pre-eclampsia on kidney function: Record linkage study.

OBJECTIVE: To assess the long term effects of hypertensive disorders of pregnancy on renal function. DESIGN: Cohort study where exposure was gestational hypertension or preeclampsia in the first pregnancy. Normotensive women formed the comparison group. SETTING: Aberdeen, Scotland. PARTICIPANTS: All women with date of birth on or before 30th June 1969 and at least their first singleton delivery recorded in the Aberdeen Maternity and Neonatal Databank. METHODS: Participants were linked to the Renal Biochemistry Register, Scottish Morbidity Records, Scottish Renal Registry and National Register for deaths. MAIN OUTCOME MEASURES: Occurrence of chronic kidney disease (CKD) as identified from renal function tests in later life, hospital admissions or death from kidney disease or recorded as receiving renal replacement therapy. RESULTS: CKD was diagnosed in 7.5% and 5.2% of women who previously had GH and PE respectively compared to 3.9% in normotensive women. The unadjusted odds ratio (95% confidence interval) of having CKD in PE was 2.04 (1.53, 2.71) and that for GH was 1.37 (1.15, 1.65), while the adjusted odds ratio (95% confidence interval) of CKD was 1.93 (1.44, 2.57) and 1.36 (1.13, 1.63) in women with PE and GH respectively. Kaplan-Meier curves of survival time to development of chronic kidney disease revealed that women with preeclampsia were susceptible to kidney function impairment earliest, followed by those with gestational hypertension. CONCLUSIONS: There was an increased subsequent risk of CKD associated with hypertensive disorders of pregnancy. Women with GH and PE were also found to have CKD earlier than normotensive women.

Selective directed self-assembly of coexisting morphologies using block copolymer blends.

Directed self-assembly (DSA) of block copolymers is an emergent technique for nano-lithography, but is limited in the range of structures possible in a single fabrication step. Here we expand on traditional DSA chemical patterning. A blend of lamellar- and cylinder-forming block copolymers assembles on specially designed surface chemical line gratings, leading to the simultaneous formation of coexisting ordered morphologies in separate areas of the substrate. The competing energetics of polymer chain distortions and chemical mismatch with the substrate grating bias the system towards either line/space or dot array patterns, depending on the pitch and linewidth of the prepattern. This is in contrast to the typical DSA, wherein assembly of a single-component block copolymer on chemical templates generates patterns of either lines/spaces (lamellar) or hexagonal dot arrays (cylinders). In our approach, the chemical template encodes desired local spatial arrangements of coexisting design motifs, self-assembled from a single, sophisticated resist.

Prevalence of blood donor iron deficiency and feasibility ferritin-based iron replacement: a blood collection agency-based study.

Iron depletion is high in frequent whole-blood donors. It is of interest to blood centres to develop ways to mitigate this risk while maintaining the current blood supply. Our feasibility study shows that blood collection agencies can measure iron stores and safely offer iron replacement in frequent blood donors with low ferritin to reduce the risk of iron depletion and future donor deferrals for low haemoglobin.

Bone induction at physiological doses of BMP through localization by clay nanoparticle gels.

Bone Morphogenic Protein 2 (BMP2) can induce ectopic bone. This ability, which first motivated the widespread application of BMP2 in fracture healing and spinal arthrodesis has, more recently, been indicated as one of several serious adverse effects associated with the supra-physiological doses of BMP2 relied upon for clinical efficacy. Key to harnessing BMPs and other agents safely and effectively will be the ability to localize activity at a target site at substantially reduced doses. Clay (Laponite) nanoparticles can self assemble into gels under physiological conditions and bind growth factors for enhanced and localized efficacy. Here we show the ability to localize and enhance the activity of BMP2 to achieve ectopic bone formation at doses within the sub-microgram per ml range of concentrations sufficient to induce differentiation of responsive cell populations in vitro and at approximately 3000 fold lower than those employed in clinical practice.