Upadacitinib Salvage Therapy for Infliximab-Experienced Patients with Acute Severe Ulcerative Colitis

BACKGROUND AND AIMS

Acute severe ulcerative colitis [ASUC] is a medical emergency treated with intravenous steroids followed by infliximab or cyclosporin in the case of steroid failure with emergent colectomy required in refractory or severe cases. Case series have reported on the effectiveness of tofacitinib for refractory disease, but data regarding the effectiveness of upadacitinib in this setting have not been previously reported. We describe the use of upadacitinib therapy for steroid-refractory ASUC in patients with prior loss of response to infliximab.

METHODS

Six patients who received upadacitinib for steroid-refractory ASUC were identified at two Australian tertiary inflammatory bowel disease centres. Patients were followed for up to 16 weeks after discharge with clinical, biochemical and intestinal ultrasound [IUS] outcomes.

RESULTS

All six patients demonstrated clinical response to upadacitinib induction during their inpatient admission. Four patients achieved corticosteroid-free clinical remission by week 8, including complete resolution of rectal bleeding and transmural healing assessed by IUS, and sustained clinical remission at week 16. One patient proceeded to colectomy at week 15 due to refractory disease. No adverse events directly attributable to upadacitinib were identified.

CONCLUSIONS

Upadacitinib may have a role as a safe and effective salvage therapy for steroid-refractory ASUC in patients who have previously failed to respond to infliximab therapy. Prospective studies are required to determine the safety and efficacy of upadacitinib use in this setting before routine use can be recommended.

Factors associated with long-term healthcare expense and steroid exposure in patients admitted with acute severe ulcerative colitis

Background and Aim

Acute severe ulcerative colitis (ASUC) remains a significant cause of morbidity and healthcare utilization. This study aimed to characterize the total healthcare costs of ASUC, explore factors associated with significant cost over the 12 months following an index admission, and document outcomes including corticosteroid exposure.

Methods

Patients admitted from January 2016 until January 2021 for ASUC to a tertiary inflammatory bowel disease (IBD) center in Australia were identified via retrospective chart review. Costs were calculated over a 12-month period following index admission.

Results

Seventy-two patients (30 [42%] female, median age 39 [IQR 27-54] years) were included. The median length of stay of index admission was 6 days (IQR 5-10 days). The median cost of index admission was 7829 AUD, which was driven by the initial length of stay (P < 0.01) and requirement for colectomy (P < 0.01). Median total healthcare cost over the first 12 months was 13 873 AUD (IQR 9684-19 936 AUD), again predominately driven by the length of stay (P < 0.01) and requirement for colectomy (P < 0.01). Median cumulative corticosteroid use over 12 months inclusive of index hospitalization was 1760 mg (IQR 1560-2350 mg). Requirement for inpatient medical salvage therapy with infliximab was associated with increased corticosteroid requirement (P = 0.01).

Conclusion

Healthcare expense related to ASUC remains high, driven predominantly by the length of stay during initial hospitalization and need for colectomy. From a healthcare cost perspective, novel methods to reduce inpatient hospital stay as well as need for colectomy may help reduce the economic and steroid burden of ASUC.

Clinical Exome Sequencing of 1000 Families with Complex Immune Phenotypes: Towards comprehensive genomic evaluations

BACKGROUND

Prospective genetic evaluation of patients at our referral research hospital presents clinical research challenges.

OBJECTIVE

This study sought not only a single-gene explanation for participants' immune-related presentations, but viewed each participant holistically, with the potential to have multiple genetic contributions to their immune-phenotype and other heritable comorbidities relevant to their presentation and health.

METHODS

We developed a program integrating exome sequencing, chromosomal microarray, phenotyping, results return with genetic counseling, and reanalysis in 1505 individuals from 1000 families with suspected or known inborn errors of immunity.

RESULTS

Probands were 50.8% female, 71.5% >18 years, and had diverse immune presentations. Overall, 327/1000 probands (32.7%) received 361 molecular diagnoses. These included 17 probands with diagnostic copy number variants, 32 probands with secondary findings, and 31 probands with multiple molecular diagnoses. Reanalysis added 22 molecular diagnoses, predominantly due to new disease-gene associations (9/22, 40.9%). One-quarter of the molecular diagnoses (92/361) did not involve immune-associated genes. Molecular diagnosis was correlated with younger age, male sex, and a higher number of organ systems involved. This program also facilitated the discovery of new gene-disease associations such as SASH3-related immunodeficiency. A review of treatment options and ClinGen actionability curations suggest that at least 251/361 (69.5%) of these molecular diagnoses could translate into >1 management option.

CONCLUSION

This program contributes to our understanding of the diagnostic and clinical utility whole exome analysis on a large scale.

CLINICAL

Implication: Comprehensive analysis of exome data has diagnostic and clinical utility for patients with suspected inborn errors of immunity.

How are medical schools supporting student’s mental wellbeing during the COVID-19 pandemic?

Introduction

The COVID-19 pandemic has impacted medical students in many ways. They are not exempt from personal struggles caused by the health crisis, and many have faced similar challenges adapting to a new learning experience. The University of East Anglia (UEA) has initiatives in place to support medical students including the society Headucate UEA and the Wellbeing Champions scheme established by Norwich Medical School (NMS).

Objectives

Headucate aims to improve mental wellbeing by educational online webinars and social events aimed at university students. NMS Wellbeing Champions offer support and signpost students to resources and the wider student support system at the UEA.

Methods

Headucate was established in 2012 by NMS students that began running workshops at local secondary schools. Their work has expanded to include wellbeing workshops, social events for students and mental health first aid training, so members can provide peer support. Wellbeing Champions are medical student representatives responsible for completing mental health first aid training, communication between students and faculty, providing resources and signposting, creating mental health bulletin newsletters, and running socials exclusively for medical students.

Results

100% of Headucate workshop attendees who completed anonymous feedback agreed that they enjoyed it and that it was useful. No feedback has been collected regarding the success of the Wellbeing Champions. This should be carried out to assess and enhance the project further.

Conclusions

More data is needed to establish the success of the initiatives at NMS and their impact on medical student’s wellbeing.

Disclosure

No significant relationships.

The Success of Headucate: The Student-Led Mental Health Society

Introduction

Headucate: University of East Anglia, a university student-led society, was founded almost 10 years ago by medical students to promote mental health education and raise awareness and funds for mental health causes.

Objectives

Headucate aims to spread mental health awareness and reduce stigma by working with schools, universities, other societies and charities internationally.

Methods

Headucate delivers workshops for children aged 4-18 in primary and secondary schools, community and youth groups and university students. These sessions were delivered in-person pre-COVID and online as interactive webinars since 2020, to spark discussion around mental health, and provide information about the variety of supports available for young people.

Results

In the past decade, Headucate UEA has grown to become one of UEA’s largest student-led groups boasting over 175 members in 2020-2021 from all courses. Within the online world, Headucate’s events have reached worldwide. The initiative has received national recognition, won national student awards and has expanded to set up three further Headucate branches nationwide. Outreach has accelerated and the school workshops reached over 1,000 students in the past year.

Conclusions

Headucate has grown from strength to strength and has plans to continue to develop, with passionate student drivers behind the project. Expansion of the project could include a national mental health university directory, bringing together like-minded mental health advocate students around the country and creating new Headucate branches across the country. To further develop, Headucate could expand outreach to the elderly community as discussed by previous committee.

Disclosure

No significant relationships.

Is TikTok increasing the number of self-diagnoses of ADHD in young people?

Introduction

TikTok is a free mobile application, that enables users to create short videos. TikTok has an estimated one billion monthly active users, comprised of a mostly younger audience. There has been a noticed rise in content discussing ADHD – hashtag ADHD on TikTok has 6.3 billion views. The discussions continue on Twitter, where users are reporting watching TikTok content explaining ADHD symptomatology, subsequently relating to the condition and requesting referrals to specialist psychiatry services. This study aims to identify key themes in discussions around TikTok and ADHD, and its ramifications.

Objectives

This study’s objective is to discuss the relationship between viewing ADHD content of TikTok and self-diagnoses of ADHD in young people.

Methods

In our study, Twitter posts were identified with the words ‘ADHD’ and ‘TikTok’ and established key themes relating to self-diagnosis of ADHD.

Results

Numerous tweets were found discussing individual’s experiences of self-diagnosis of ADHD after watching TikTok videos and relating with the symptomology. Furthermore, many users discussed their efforts to seek diagnosis from psychiatrists. These posts highlighted positive discussion of mental health, and the improvement in quality of life since diagnosis.

Conclusions

Many young people are self-diagnosing ADHD after viewing TikTok videos. This may improve mental health stigma, however the expertise of the video creators should be scrutinised. Furthermore, the impact on already stretched waiting lists should be considered, with individuals who’s perceived ADHD traits are not impacting on their quality of life.

Disclosure

No significant relationships.

The impact of COVID-19 on mental health charity fundraising: An account from the perspective of fundraisers

Introduction

The dawn of COVID-19 brought new rules, restrictions, and lockdowns but this led to the unlikely fall of many sectors, including the charitable sector. There has been a significant decline in funding received by mental health charities, especially during the pandemic. This study looks at the subsequent impact on fundraisers and mental health promotion during COVID-19.

Objectives

The main aim was to uncover how the COVID-19 pandemic has affected the way that mental health charities fundraise, raise awareness, and promote mental health. This aimed to look at the impact of the COVID-19 pandemic on fundraisers supporting mental health charities and their opinion on whether fundraising has either helped or hindered mental health promotion.

Methods

Accounts from fundraisers and local representatives for mental health charities during the COVID-19 pandemic were analysed. Common themes looked at the impact, adaptation, and reasons why fundraisers decided to help during a tough period for the charitable sector.

Results

Mental health charities expressed difficulty in sourcing funds to support their users, especially in a vulnerable time. Fundraisers tried innovative ways to promote mental health and raise money for charities.

Conclusions

Altruism and understanding how precious services such as mental health charities are for the population was the main driver for fundraisers. Mental health charities adapted by turning to online communication and reached out to fundraisers to continually highlight the importance of mental health to their users and fundraisers.

Disclosure

No significant relationships.

Higher Anti-tumor Necrosis Factor-α Levels Correlate With Improved Radiologic Outcomes in Crohn's Perianal Fistulas

BACKGROUND & AIMS

Higher anti-tumor necrosis factor-α (TNF) drug levels are associated with improved clinical healing of Crohn's perianal fistulas. It is unclear whether this leads to improved healing on radiologic assessment. We aimed to evaluate the association between anti-TNF drug levels and radiologic outcomes in perianal fistulising Crohn's disease.

METHODS

A cross-sectional retrospective multicenter study was undertaken. Patients with perianal fistulising Crohn's disease on maintenance infliximab or adalimumab, with drug levels within 6 months of perianal magnetic resonance imaging were included. Patients receiving dose changes or fistula surgery between drug level and imaging were excluded. Radiologic disease activity was scored using the Van Assche Index, with an inflammatory subscore calculated using indices: T2-weighted imaging hyperintensity, collections >3 mm diameter, rectal wall involvement. Primary endpoint was radiologic healing (inflammatory subscore ≤6). Secondary endpoint was radiologic remission (inflammatory subscore = 0).

RESULTS

Of 193 patients (infliximab, n = 117; adalimumab, n = 76), patients with radiologic healing had higher median drug levels compared with those with active disease (infliximab 6.0 vs 3.9 μg/mL; adalimumab 9.1 vs 6.2 μg/mL; both P < .05). Patients with radiologic remission also had higher median drug levels compared with those with active disease (infliximab 7.4 vs 3.9 μg/mL; P < .05; adalimumab 9.8 vs 6.2 μg/mL; P = .07). There was a significant incremental reduction in median inflammatory subscores with higher anti-TNF drug level tertiles.

CONCLUSIONS

Higher anti-TNF drug levels were associated with improved radiologic outcomes on magnetic resonance imaging in perianal fistulising Crohn's disease, with an incremental improvement at higher drug level tertiles for both infliximab and adalimumab.

The impact of Gender Identity Clinic waiting times on the mental health of transitioning individuals

Introduction

Waiting times for gender identity services, even before the Covid-19 pandemic, have been a cause of concern. Despite the waiting time standard for planned elective care in the NHS being a maximum of 18 weeks, the average waiting time for a first appointment with a gender identity clinic is 18 months. This study aims to analyse the effect that these timings have on the transgender community, and whether they impact the risk of developing mental health conditions such as depression or anxiety.

Objectives

This study’s main aim is to analyse the correlation between waiting times and mental health burden in the transgender community.

Methods

A literature review and analysis on a transgender individual’s mental health and waiting times for Gender Identity Clinics; looking at any key themes and conclusions. Research papers were taken from MEDLINE, The International Journal of Transgender Health, Oxford Academic, SpringerLink and Emerald Insight, with studies publishing date ranging from 2014 – 2021.

Results

The transgender population were found to have higher rates of suicidal ideation, depression and self harm compared to the general population. Longer waiting times were found to contribute to feelings of low mood and suicidal ideation, as well as decreasing overall quality of life.

Conclusions

Longer waiting times can decrease a transgender individual’s quality of life and impact their overall mental wellbeing: especially with the impact of COVID-19 and the rise in referrals.

Disclosure

No significant relationships.

Systematic review and meta-analysis: evaluating response to empiric anti-TNF dose intensification for secondary loss of response in Crohn's disease

INTRODUCTION

Anti-tumor necrosis factor (TNF) dose intensification represents an effective method of overcoming secondary loss of response (LOR); however, a subset of patients may not respond (tertiary non-response), or fail to demonstrate durable response (tertiary LOR) to intensified dosing. This systematic review and meta-analysis aimed to evaluate these outcomes to determine the clinical effectiveness of empiric dose intensification in Crohn's disease.

METHODS

Multiple databases including MEDLINE and EMBASE were interrogated to identify studies that reported outcomes following anti-TNF dose intensification to address secondary LOR in Crohn's disease. Studies that used anti-TNF levels as the primary basis for dose intensification were excluded. Studies that reported (1) tertiary response and tertiary non-response within 6 months or (2) tertiary response and tertiary LOR beyond 6 months, were pooled using a random effects model with risk ratio (RR) derived, quantifying the effect of each comparison.

RESULTS

Twenty-six studies reported outcomes following anti-TNF dose intensification to address secondary LOR. Short-term response within 12 weeks of any dose-intensification strategy was 33-90%, while sustained response (⩾48 weeks) was achieved in 25-85%. Tertiary non-response occurred in up to 45% of intensified patients within 6 months of anti-TNF dose intensification, while tertiary LOR beyond 6 months occurred in up to 64% of patients. Tertiary response was more likely than tertiary non-response within 6 months (RR 2.58, 95% CI (1.76, 3.79), I ² = 82%, 12 studies), while sustained response beyond 6 months compared to tertiary LOR (RR 1.10 (0.75, 1.61) I ² = 85%, 7 studies) was less convincing.

CONCLUSION

Although anti-TNF dose intensification is clinically effective in patients with Crohn's disease, particularly within the first 6 months, a proportion of patients will fail to demonstrate short-term and/or sustained clinical response. Hence, clinical reassessment following anti-TNF dose intensification, particularly beyond 6 months, remains important to differentiate between effective and ineffective dose-intensification strategies.

Sequential Use of High-Dose Tofacitinib After Infliximab Salvage Therapy in Acute Severe Ulcerative Colitis

BACKGROUND AND AIMS

Preliminary data regarding the effectiveness of tofacitinib in acute severe ulcerative colitis [ASUC] have been presented in two previous case series. We aimed to describe the novel use of high-dose tofacitinib immediately following non-response to infliximab in the setting of steroid-refractory ASUC.

METHODS

Five patients who received high-dose tofacitinib 10 mg three times a day immediately following non-response to infliximab for steroid-refractory ASUC were identified at an Australian tertiary inflammatory bowel disease centre.

RESULTS

Four of the five patients demonstrated clinical response to high-dose tofacitinib induction during their inpatient admission, with one patient requiring colectomy owing to a lack of clinical response. At 90 days, all four initial responders remained colectomy-free, with two patients achieving combined clinical and endoscopic remission. No adverse events directly attributable to high-dose tofacitinib were identified.

CONCLUSIONS

High-dose tofacitinib may have a role as salvage therapy in the setting of steroid-refractory ASUC. Prospective studies are required to determine the safety and efficacy of high-dose tofacitinib to determine whether it can be routinely recommended as primary or sequential salvage therapy in the setting of steroid-refractory ASUC.

Some elements for a history of the dynamical systems theory

Writing a history of a scientific theory is always difficult because it requires to focus on some key contributors and to "reconstruct" some supposed influences. In the 1970s, a new way of performing science under the name "chaos" emerged, combining the mathematics from the nonlinear dynamical systems theory and numerical simulations. To provide a direct testimony of how contributors can be influenced by other scientists or works, we here collected some writings about the early times of a few contributors to chaos theory. The purpose is to exhibit the diversity in the paths and to bring some elements-which were never published-illustrating the atmosphere of this period. Some peculiarities of chaos theory are also discussed.

SAT0003 ELEVATED BASELINE AND INCREASING AUTOANTIBODY LEVELS ARE ASSOCIATED WITH INCREASED RISK FOR IMMINENT ONSET OF INFLAMMATORY ARTHRITIS IN A PROSPECTIVELY STUDIED ANTI-CITRULLINATED PROTEIN ANTIBODY POSITIVE COHORT: THE TIP-RA COLLECTIVE

Background:

The Targeting Immune Responses for Prevention of RA (TIP-RA) Collaborative prospectively studies individuals at high risk for developing RA because of serum ACPA positivity in absence of baseline inflammatory arthritis (IA).

Objectives:

The objective of the analyses presented herein is to evaluate the role of baseline and changing levels of ACPA and rheumatoid factor (RF) in relationship to incident IA/RA.

Methods:

ACPA+ subjects and ACPA- controls were identified who did not have baseline historical or examination evidence of IA. ACPA+ was defined by serum elevation of anti-CCP3 ≥20 units (Inova). Subjects were evaluated annually or sooner if they had changes in joint symptoms. Factors including RFIgM and RFIgA (Inova) were also assessed, and relationships between autoantibody levels at baseline and over time and incident IA/RA were evaluated using t-tests, with paired testing where applicable.

Results:

Baseline characteristics of ACPA+ and ACPA- subjects are in Table 1. Sixteen of the 94 (17%) ACPA+ subjects developed IA/RA a mean of 518 days from the baseline visit; 14 of these met 2010 ACR/EULAR criteria for RA at the time of detection of IA. There was a trend for ACPA+ subjects who later developed IA/RA to have higher baseline levels of anti-CCP3 compared to those who did not develop IA/RA (Table 2). In addition, those who developed IA/RA had significantly higher mean levels of RFIgM and RFIgA compared to those who did not. While not statistically significant, in longitudinal analyses in the ACPA+ subjects with incident IA/RA, anti-CCP3 levels increased from baseline to identification of IA (mean [SD] of 119 [102] to 126 [100], p=0.42). Furthermore, RFIgM levels increased from 36 [49] at baseline to 43 [51] at the time of IA (p=0.31), and RFIgA levels increased from 16 [29] to 21 [31] (p=0.10). In contrast, in ACPA+ subjects who did not develop IA/RA, anti-CCP3 levels increased only slightly over follow-up of a mean of 712 days: 75 [75] to 80 [76], p=0.70 while the levels of RFIgM and RFIgA decreased slightly during the same follow-up: for RFIgM mean [SD] levels went from 9 [22] to 8 [19], p=0.74; for RFIgA, 5 [16] to 3 [12], p=0.67.

Table 1.

Baseline characteristics of ACPA+/- subjects

ACPA-(n=162)ACPA+(n=94)p-valueAge, mean58580.90% Female69680.67% Ever smoker33340.87RF-IgM, mean (SD)3.2 (10.0)13.5 (30.2)<0.01RF-IgA, mean (SD)0.3 (0.6)6.5 (19.1)<0.01Table 2.

Baseline characteristics of 16 ACPA+ subjects who developed incident IA/RA vs. 78 ACPA+ who did not

Did not develop IA/RA (n=78)Developed IA/RA (n=16)p-valueDays from baseline to IA/RA or follow-up, mean (SD)712 (124)518 (295)–% Meeting 2010 criteria at time of IA-88–CCP3, mean (SD)74.5 (75.3)119.1 (102.1)0.05RFIgM, mean (SD)9 (22)36 (49)<0.01RFIgA, mean (SD)4 (16)16 (29)0.03

Conclusion:

In this prospectively followed cohort of ACPA+ subjects, higher levels of RFIgM and RFIgA at baseline were significantly associated with development of IA/RA within the follow-up period. Furthermore, there was a trend for rising levels of anti-CCP3 and RFIgM and A to be associated with development of IA/RA. These finding support the use of higher and/or rising levels of autoantibodies as additional features to predict imminent onset of IA/RA in ACPA+ individuals as well as potentially to use as outcomes of success of preventive interventions. Furthermore, the trend of increasing levels of RFIgM and RFIgA over time in individuals who developed IA/RA suggests that targeting pathways of RF development may lead to preventive interventions in a subset of RA.

References:

None

Disclosure of Interests:

Kevin Deane Grant/research support from: Janssen, Consultant of: Inova, ThermoFisher, Janseen, BMS and Microdrop, Gary Firestein Grant/research support from: Lilly, Janssen, Abbvie, David Boyle: None declared, Jane Buckner Grant/research support from: Bristol-Myers Squibb, Janssen, Eddie A. James Grant/research support from: Janssen, Pfizer, Sanofi, Novartis, Sylvia Posso Grant/research support from: Janssen, William Robinson Grant/research support from: Janssen, Laurie K. Moss Grant/research support from: Janssen, Jennifer Seifert Grant/research support from: Janssen, Roger Gilmore Grant/research support from: Janssen, Saman Barzideh Grant/research support from: Janssen, Navin Rao Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Frederic Baribaud Shareholder of: Janssen Research & Development, LLC, Employee of: Janssen Research & Development, LLC, Sunil Nagpal Shareholder of: Janssen Pharmaceuticals, Employee of: Janssen Pharmaceuticals, Alyssa Johnsen Employee of: Janssen, V. Michael Holers Grant/research support from: Janssen, Celgene, and BMS

‘TAG, You’re It!’ The high-stakes game of handovers in the Emergency Department – Improving handover quality using a new ‘TAG’ Protocol

Aim To assess handover quality amongst Emergency Department (ED) physicians and improve quality by implementing a unique protocol entitled ‘TAG, You’re It!’ (TAG protocol). Methods Patient charts assessed using set parameters prior to implementation of the ‘TAG’ protocol. ‘TAG’ protocol developed based on gaps in current practice and recommendations from literature. Identical parameters applied post-intervention, and results compared to those pre-intervention. Results ‘TAG’ protocol yielded positive impact on ED handover practices. A significant difference (p<0.05) between pre and post-TAG intervention values was seen across all parameters i.e. including the accepting physician’s name in the computer system and ED chart, documenting a handover plan in the ED chart, and including a handover plan deemed sufficient by standards developed from relevant literature. Conclusion Shift-to-shift handover in the ED is a high risk time for patient safety. The ‘TAG’ protocol ensures that essential information is documented and communicated in a succinct and rapid way.

Algorithms for concatenating templates

We present two algorithms for concatenating two branched manifolds. There exist two common ways to describe representations of branched manifolds with linking matrices. The algorithms provided permit to concatenate branched manifolds with each representation: a linking matrix with an array or only one linking matrix. We also provide algorithms to switch between these two descriptions.

Dressed return maps distinguish chaotic mechanisms

Chaotic data generated by a three-dimensional dynamical system can be embedded into R(3) in a number of inequivalent ways. However, when lifted into R(5) they all become equivalent, indicating that they all belong to a single universality class sharing a common chaos-generating mechanism. We present a complete invariant determining this universality class and distinguishing attractors generated by distinct mechanisms. This invariant is easily computable from an appropriately "dressed" return map of any particular three-dimensional embedding.

Coagulation factor activity and clinical bleeding severity in rare bleeding disorders: results from the European Network of Rare Bleeding Disorders

BACKGROUND

The European Network of Rare Bleeding Disorders (EN-RBD) was established to bridge the gap between knowledge and practise in the care of patients with RBDs.

OBJECTIVES

To explore the relationship between coagulation factor activity level and bleeding severity in patients with RBDs.

PATIENTS/METHODS

Cross-sectional study using data from 489 patients registered in the EN-RBD. Coagulation factor activity levels were retrieved. Clinical bleeding episodes were classified into four categories according to severity.

RESULTS

The mean age of patients at data collection was 31 years (range, 7 months to 95 years), with an equal sex distribution. On linear regression analysis, there was a strong association between coagulation factor activity level and clinical bleeding severity for fibrinogen, factor (F) X, FXIII, and combined FV and FVIII deficiencies. A weaker association was present for FV and FVII deficiencies. There was no association between coagulation factor activity level and clinical bleeding severity for FXI. The coagulation factor activity levels that were necessary for patients to remain asymptomatic were: fibrinogen, > 100 mg dL(-1); FV, 12 U dL(-1); combined FV + VIII, 43 U dL(-1); FVII, 25 U dL(-1); FX, 56 U dL(-1) ; FXI, 26 U dL(-1); FXIII, 31 U dL(-1). Moreover, coagulation factor activity levels that corresponded with Grade III bleeding were: undetectable levels for fibrinogen, FV and FXIII, < 15 U dL(-1) for combined FV + VIII; < 8 U dL(-1) for FVI; < 10 U dL(-1) for FX; and < 25 U dL(-1) for FXI.

CONCLUSIONS

There is a heterogeneous association between coagulation factor activity level and clinical bleeding severity in different RBDs. A strong association is only observed in fibrinogen, FX and FXIII deficiencies.

Complete set of representations for dissipative chaotic three-dimensional dynamical systems

Embeddings are diffeomorphisms between some dynamical phase space and a reconstructed image. Different embeddings may or may not be equivalent under isotopy. We regard embeddings as representations of the dynamical phase space. We determine the topological labels required to distinguish inequivalent representations of three-dimensional dissipative dynamical systems when the embeddings are into R(k), k=3,4,5,…. Three representation labels are required for embeddings into R³, and only one is required in R⁴. In R⁵ there is a single "universal" representation.

Deuterium nuclear magnetic resonance investigation of the effects of proteins and polypeptides on hydrocarbon chain order in model membrane systems

Deuterium Fourier-transform nuclear magnetic resonance spectra have been obtained of 1-myristoyl 2-(14,14,14-trideutero)myristoyl phosphatidylcholine bilayers at 34.1 MHz by using the quadrupole echo pulse technique. Thereby, we have investigated the effects upon the deuterated dimyristoyl phosphatidylcholine bilayers of the following proteins and polypeptides: gramicidin A, bacteriophage f1 coat protein, beef brain myelin proteolipid apoprotein, cytochrome b(5), and cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1). Above T(c), the transition temperature between the gel and liquid crystal phases, the quadrupole splitting of the deuterium-labeled methyl group is reduced or collapsed in the presence of protein or polypeptide. No evidence has been found for ordered "boundary lipid." Below T(c), the spectra show that the hydrocarbon chains are prevented from crystallizing by the protein (or polypeptide) incorporated in the membrane. Similar disordering effects above T(c) are also seen when an unsaturated lipid, 1-(16,16,16-trideutero)palmitoyl 2-palmitoleyl phosphatidylcholine is complexed with cytochrome oxidase.

Differential embedding of the Lorenz attractor

Ideally an embedding of an N -dimensional dynamical system is N -dimensional. Ideally, an embedding of a dynamical system with symmetry is symmetric. Ideally, the symmetry of the embedding is the same as the symmetry of the original system. This ideal often cannot be achieved. Differential embeddings of the Lorenz system, which possesses a twofold rotation symmetry, are not ideal. While the differential embedding technique happens to yield an embedding of the Lorenz attractor in three dimensions, it does not yield an embedding of the entire flow. An embedding of the flow requires at least four dimensions. The four dimensional embedding produces a flow restricted to a twisted three dimensional manifold in R4. This inversion symmetric three-manifold cannot be projected into any three dimensional Euclidean subspace without singularities.

Biological algorithm for data reconstruction

An algorithm inspired by Genome sequencing is proposed which "reconstructs" a single long trajectory of a dynamical system from many short trajectories. This procedure is useful in situations when many data sets are available but each is insufficiently long to apply a meaningful analysis directly. The algorithm is applied to the Rössler and Lorenz dynamical systems as well as to experimental data taken from the Belousov-Zhabotinskii chemical reaction. Topological information was reliably extracted from each system and geometrical and dynamical measures were computed.

Representation theory for strange attractors

Embeddings are diffeomorphisms between some unseen physical attractor and a reconstructed image. Different embeddings may or may not be equivalent under isotopy. We regard embeddings as representations of the attractor, review the labels required to distinguish inequivalent representations for an important class of dynamical systems, and discuss the systematic ways inequivalent embeddings become equivalent as the embedding dimension increases until there is finally only one "universal" embedding in a suitable dimension.

Activated protein C resistance, factor V Leiden and assessment of thrombotic risk

Venous thromboembolism comprises deep vein thrombosis (DVT) and pulmonary embolism (PE). Acute venous thromboembolism (VTE) is a serious and potentially fatal disorder which often complicates the course of hospitalized patients, but also affects ambulatory and otherwise healthy people. The annual incidence of venous thromboembolism is 1 to 2 cases per 1000 person and the risk of the disorder rises exponentially with age, from an annual rate of less than 5 per 100,000 children to greater than 400 per 100,000 adults older than 80 years.

Comparison of tests for embeddings

It is possible to compare results for the classical tests for embeddings of chaotic data with the results of a recently proposed test. The classical tests, which depend on real numbers (fractal dimensions, Lyapunov exponents) averaged over an attractor, are compared with a topological test that depends on integers. The comparison can only be done for mappings into three dimensions. We find that the classical tests fail to predict when a mapping is an embedding and when it is not. We point out the reasons for this failure, which are not restricted to three dimensions.