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1.
Article in English | MEDLINE | ID: mdl-38818853

ABSTRACT

Peptic ulcer disease is an important cause of upper gastrointestinal bleeding. Current guidelines recommend endoscopic treatment for ulcers with active bleeding or non-bleeding visible vessels, but the optimal management of ulcers with adherent clots is unclear. We performed a systematic review of the efficacy of endoscopic versus medical management of peptic ulcers with adherent clots. A systematic literature search was performed through September 2022 (MEDLINE, Embase, and CENTRAL). Randomized controlled trials (RCTs) comparing the effect of endoscopic versus medical management alone for peptic ulcers with adherent clots on the outcome of recurrent bleeding were incuded. A random-effects meta-analysis was performed to estimate the overall treatment effect. We included seven RCTs reporting on the endoscopic versus medical management of peptic ulcers with adherent clots. The pooled cohort comprised 268 patients with a mean age of 62.8 years and a mean follow up of 20 days. There was a significant reduction in the risk of recurrent bleeding with endoscopic hemostatic treatment for peptic ulcers with adherent clots, compared with medical management alone (risk ratio [RR] = 0.40, 95% confidence interval [CI] 0.16-0.95, 268 participants). However, there was no difference in mortality (RR = 0.90, 95% CI 0.23-3.59, 52 participants) or need for ulcer surgery (RR = 0.48, 95% CI 0.10-2.28, 52 participants) between endoscopic and medical management groups. In summary, there was evidence for a reduction in recurrent bleeding from peptic ulcers with adherent clots treated with endoscopic hemostatic techniques compared with medical management alone but no difference in rates of mortality or need for surgery.

2.
J Allergy Clin Immunol ; 150(4): 947-954, 2022 10.
Article in English | MEDLINE | ID: mdl-35753512

ABSTRACT

BACKGROUND: Prospective genetic evaluation of patients at this referral research hospital presents clinical research challenges. OBJECTIVES: 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: This study 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% were ≥18 years, and had diverse immune presentations. Overall, 327 of 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 of 22, 40.9%). One-quarter of the molecular diagnoses (92 of 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 of 361 of these molecular diagnoses (69.5%) could translate into ≥1 management option. CONCLUSIONS: This program contributes to our understanding of the diagnostic and clinical utility whole exome analysis on a large scale.


Subject(s)
Exome , Genetic Testing , Exome/genetics , Female , Genetic Testing/methods , Genomics , Humans , Male , Phenotype , Prospective Studies
3.
Clin Gastroenterol Hepatol ; 20(6): 1306-1314, 2022 06.
Article in English | MEDLINE | ID: mdl-34389484

ABSTRACT

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.


Subject(s)
Crohn Disease , Rectal Fistula , Adalimumab/therapeutic use , Crohn Disease/complications , Crohn Disease/diagnostic imaging , Crohn Disease/drug therapy , Cross-Sectional Studies , Humans , Infliximab/therapeutic use , Rectal Fistula/diagnostic imaging , Rectal Fistula/drug therapy , Retrospective Studies , Treatment Outcome , Tumor Necrosis Factor Inhibitors , Tumor Necrosis Factor-alpha
4.
Intern Med J ; 52(3): 365-368, 2022 Mar.
Article in English | MEDLINE | ID: mdl-33009857

ABSTRACT

Cytomegalovirus (CMV) infection can be a challenging clinical problem in patients with inflammatory bowel disease (IBD), particularly ulcerative colitis. Clinical presentation is difficult to distinguish from an underlying disease flare. Several diagnostic modalities are now available and when combined can aid clinicians in the identification of patients who are most likely to benefit from antiviral therapy. The aim of this article is to review the available literature and outline a practical approach to the diagnosis and management of CMV in patients with IBD.


Subject(s)
Colitis, Ulcerative , Cytomegalovirus Infections , Inflammatory Bowel Diseases , Chronic Disease , Colitis, Ulcerative/diagnosis , Colitis, Ulcerative/drug therapy , Cytomegalovirus , Cytomegalovirus Infections/complications , Cytomegalovirus Infections/diagnosis , Cytomegalovirus Infections/therapy , Humans , Inflammatory Bowel Diseases/diagnosis , Inflammatory Bowel Diseases/therapy
5.
Chaos ; 31(5): 053110, 2021 May.
Article in English | MEDLINE | ID: mdl-34240941

ABSTRACT

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.

9.
Chaos ; 26(3): 033102, 2016 Mar.
Article in English | MEDLINE | ID: mdl-27036180

ABSTRACT

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.

10.
Infect Immun ; 82(12): 5110-6, 2014 Dec.
Article in English | MEDLINE | ID: mdl-25245809

ABSTRACT

The complex segmented genome of Borrelia burgdorferi is comprised of a linear chromosome along with numerous linear and circular plasmids essential for tick and/or mammalian infectivity. The pathogenic necessity for specific borrelial plasmids has been identified; most notably, infections of the tick vector and mammalian host both require linear plasmid 25 (lp25). Genes carried on lp25, specifically bptA and pncA, are postulated to play a role for B. burgdorferi to infect and persist in Ixodes ticks. In this study, we complemented an lp25-deficient borrelial strain with pncA alone or pncA accompanied by bptA to evaluate the ability of the complemented strains to restore larval colonization and persistence through transstadial transmission relative to that of wild-type B. burgdorferi. The acquisition of the complemented strains by tick larvae from infected mice and/or the survival of these strains was significantly decreased when assayed by cultivation and quantitative PCR (qPCR). Only 10% of the pncA-complemented strain organisms were found by culture to survive 17 days following larval feeding, while 45% of the pncA- and bptA-complemented strain organisms survived, with similar results by PCR. However, neither of the complemented B. burgdorferi strains was capable of persisting through the molt to the nymphal stage as analyzed by culture. qPCR analyses of unfed nymphs detected B. burgdorferi genomes in several nymphs at low copy numbers, likely indicating the presence of DNA from dead or dying cells. Overall, the data indicate that pncA and bptA cannot independently support infection, suggesting that lp25 carries additional gene(s) or regulatory elements critical for B. burgdorferi survival and pathogenesis in the Ixodes vector.


Subject(s)
Amidohydrolases/genetics , Bacterial Outer Membrane Proteins/genetics , Borrelia burgdorferi/physiology , Ixodes/microbiology , Plasmids , Virulence Factors/genetics , Amidohydrolases/metabolism , Animals , Bacterial Load , Bacterial Outer Membrane Proteins/metabolism , Borrelia burgdorferi/growth & development , Genes, Bacterial , Genetic Complementation Test , Larva/microbiology , Mice, Inbred C3H , Microbial Viability , Real-Time Polymerase Chain Reaction , Virulence , Virulence Factors/metabolism
11.
Nurs Outlook ; 62(5): 352-61, 2014.
Article in English | MEDLINE | ID: mdl-25015404

ABSTRACT

Increasingly, scientific funding agencies are requiring that researchers move toward an integrated, transdisciplinary team science paradigm. Although the barriers to and rewards of conducting this type of research have been discussed in the literature, examples of how nurse investigators have led these teams to reconcile the differences in theoretical, methodological, and/or analytic perspectives that inevitably exist are lacking. In this article, we describe these developmental trajectory challenges through a case study of one transdisciplinary team, focusing on team member characteristics and the leadership tasks associated with successful transdisciplinary science teams in the literature. Specifically, we describe how overcoming these challenges has been essential to examining the complex and potentially cumulative effects that key intersections between legal, social welfare, and labor market systems may have on the health of disadvantaged women. Finally, we discuss this difficult but rewarding work within the context of lessons learned and transdisciplinary team research in relation to the future of nursing science.


Subject(s)
Interdisciplinary Communication , Nursing Research/organization & administration , Patient Care Team/organization & administration , Female , Humans , Male , Men's Health , Models, Organizational , Organizational Case Studies , United States , Vulnerable Populations , Women's Health
12.
Ticks Tick Borne Dis ; 15(3): 102324, 2024 May.
Article in English | MEDLINE | ID: mdl-38367587

ABSTRACT

A Borrelia miyamotoi gene with partial homology to bipA of relapsing fever spirochetes Borrelia hermsii and Borrelia turicatae was identified by a GenBank basic alignment search analysis. We hypothesized that this gene product may be an immunogenic antigen as described for other relapsing fever Borrelia (RFB) and could serve as a serological marker for B. miyamotoi infections. The B. miyamotoi gene was a truncated version about half the size of the B. hermsii and B. turicatae bipA with a coding sequence of 894 base pairs. The gene product had a calculated molecular size of 32.7 kDa (including the signal peptide). Amino acid alignments with B. hermsii and B. turicatae BipA proteins and with other B. miyamotoi isolates showed conservation at the carboxyl end. We cloned the B. miyamotoi bipA-like gene (herein named bipM) and generated recombinant protein for serological characterization and for antiserum production. Protease protection analysis demonstrated that BipM was surface exposed. Serologic analyses using anti-B. miyamotoi serum samples from tick bite-infected and needle inoculated mice showed 94 % positivity against BipM. The 4 BipM negative serum samples were blotted against another B. miyamotoi antigen, BmaA, and two of them were seropositive resulting in 97 % positivity with both antigens. Serum samples from B. burgdorferi sensu stricto (s.s.)-infected mice were non-reactive against rBipM by immunoblot. Serum samples from Lyme disease patients were also serologically negative against BipM except for 1 sample which may have indicated a possible co-infection. A recently published study demonstrated that B. miyamotoi BipM was non-reactive against serum samples from B. hermsii, Borrelia parkeri, and B. turicatae infected animals. These results show that BipM has potential for a B. miyamotoi-infection specific and sensitive serodiagnostic to differentiate between Lyme disease and various RFB infections.


Subject(s)
Borrelia Infections , Borrelia , Lyme Disease , Relapsing Fever , Humans , Animals , Mice , Relapsing Fever/diagnosis , Lyme Disease/diagnosis , Borrelia Infections/diagnosis , Antigens
13.
BMJ Open ; 14(7): e081787, 2024 Jul 20.
Article in English | MEDLINE | ID: mdl-39032928

ABSTRACT

INTRODUCTION: A substantial proportion of patients with inflammatory bowel disease (IBD) on intravenous infliximab require dose intensification. Accessing additional intravenous infliximab is labour-intensive and expensive, depending on insurance and pharmaceutical reimbursement. Observational data suggest that subcutaneous infliximab may offer a convenient and safe alternative to maintain disease remission in patients requiring dose-intensified infliximab. A prospective, controlled trial is required to confirm that subcutaneous infliximab is as effective as dose-intensified intravenous infliximab, to identify predictors of disease flare and to establish the role of subcutaneous infliximab therapeutic drug monitoring. METHODS AND ANALYSIS: The DISCUS-IBD trial is an investigator-initiated, prospective, multicentre, randomised, open-label non-inferiority study comparing the rate of disease flares in participants randomised to continue dose-intensified intravenous infliximab to those switched to subcutaneous infliximab after 48 weeks. Participants are adult patients with IBD in sustained corticosteroid-free remission on any regimen of dose-intensified infliximab up to a maximum of 10 mg/kg 4-weekly intravenously. Participants allocated to intravenous infliximab will continue infliximab at the same dose-intensified regimen they were receiving at study enrolment. Subcutaneous infliximab dosing will be stratified by prior intravenous infliximab dosing. Clinical (Harvey-Bradshaw Index, partial Mayo score), biochemical (C reactive protein, faecal calprotectin), pharmacokinetic (drug-level±antidrug antibodies) and qualitative data are collected 12-weekly until study conclusion at week 48. 13 sites across Australia will participate in recruitment to reach a calculated sample size of 120 participants. ETHICS AND DISSEMINATION: Multisite ethics approval was obtained from the Health District Human Research Ethics Committee (HREC) at The Alfred Hospital under a National Mutual Acceptance (NMA) agreement (HREC/90559/Alfred-2022; Local Reference: Project 618/22, version 1.6, 2 March 2023). Findings will be reported at national and international gastroenterology meetings and published in peer-reviewed journals. DISCUS-IBD was prospectively registered with the Australian and New Zealand Clinical Trials Registry (ANZCTR) prior to commencing recruitment. TRIAL REGISTRATION NUMBER: ACTRN12622001458729.


Subject(s)
Gastrointestinal Agents , Inflammatory Bowel Diseases , Infliximab , Humans , Infliximab/administration & dosage , Infliximab/therapeutic use , Infliximab/pharmacokinetics , Inflammatory Bowel Diseases/drug therapy , Prospective Studies , Gastrointestinal Agents/administration & dosage , Gastrointestinal Agents/therapeutic use , Injections, Subcutaneous , Administration, Intravenous , Multicenter Studies as Topic , Adult , Australia , Drug Monitoring/methods , Female , Male
14.
Infect Immun ; 81(7): 2488-98, 2013 Jul.
Article in English | MEDLINE | ID: mdl-23630963

ABSTRACT

The impact of the Borrelia burgdorferi surface-localized immunogenic lipoprotein BBA66 on vector and host infection was evaluated by inactivating the encoding gene, bba66, and characterizing the mutant phenotype throughout the natural mouse-tick-mouse cycle. The BBA66-deficient mutant isolate, Bb(ΔA66), remained infectious in mice by needle inoculation of cultured organisms, but differences in spirochete burden and pathology in the tibiotarsal joint were observed relative to the parental wild-type (WT) strain. Ixodes scapularis larvae successfully acquired Bb(ΔA66) following feeding on infected mice, and the organisms persisted in these ticks through the molt to nymphs. A series of tick transmission experiments (n = 7) demonstrated that the ability of Bb(ΔA66)-infected nymphs to infect laboratory mice was significantly impaired compared to that of mice fed upon by WT-infected ticks. trans-complementation of Bb(ΔA66) with an intact copy of bba66 restored the WT infectious phenotype in mice via tick transmission. These results suggest a role for BBA66 in facilitating B. burgdorferi dissemination and transmission from the tick vector to the mammalian host as part of the disease process for Lyme borreliosis.


Subject(s)
Antigens, Bacterial/metabolism , Borrelia burgdorferi/pathogenicity , Gene Silencing , Ixodes/microbiology , Lyme Disease/transmission , Animals , Antigens, Bacterial/genetics , Arachnid Vectors/microbiology , Arachnid Vectors/physiology , Borrelia burgdorferi/genetics , Borrelia burgdorferi/metabolism , Feeding Behavior/physiology , Female , Fluorescent Antibody Technique, Indirect , Gene Expression Regulation, Bacterial , Genes, Bacterial , Genetic Complementation Test , Ixodes/physiology , Larva/microbiology , Larva/physiology , Lyme Disease/microbiology , Mice , Mice, Inbred C3H , Mutagenesis, Insertional , Transcription, Genetic
15.
Proc Natl Acad Sci U S A ; 107(16): 7515-20, 2010 Apr 20.
Article in English | MEDLINE | ID: mdl-20368453

ABSTRACT

The spirochetal agent of Lyme disease, Borrelia burgdorferi, is transmitted by bites of Ixodes ticks to mammalian reservoir hosts and humans. The mechanism(s) by which the organism is trafficked from vector to host is poorly understood. In this study, we demonstrate that a B. burgdorferi mutant strain deficient in the synthesis of the bba64 gene product was incapable of infecting mice via tick bite even though the mutant was (i) infectious in mice when introduced by needle inoculation, (ii) acquired by larval ticks feeding on infected mice, and (iii) able to persist through tick molting stages. This finding of a B. burgdorferi gene required for pathogen transfer and/or survival from the tick to the susceptible host represents an important breakthrough toward understanding transmission mechanisms involved for the Lyme disease agent.


Subject(s)
Borrelia burgdorferi/metabolism , Gene Expression Regulation , Genes, Bacterial/genetics , Lyme Disease/microbiology , Alleles , Animals , Female , Genes, Bacterial/physiology , Genetic Complementation Test , Ixodes , Larva/metabolism , Larva/microbiology , Mice , Models, Genetic , Mutation , Phenotype , Spirochaetales/genetics
16.
Microbiol Spectr ; : e0430122, 2023 Jan 30.
Article in English | MEDLINE | ID: mdl-36715531

ABSTRACT

Borrelia miyamotoi is a relapsing fever spirochete that is harbored by Ixodes spp. ticks and is virtually uncharacterized, compared to other relapsing fever Borrelia vectored by Ornithodoros spp. ticks. There is not an immunocompetent mouse model for studying B. miyamotoi infection in vivo or for transmission in the vector-host cycle. Our goal was to evaluate B. miyamotoi infections in multiple mouse breeds/strains as a prelude to the ascertainment of the best experimental infection model. Two B. miyamotoi strains, namely, LB-2001 and CT13-2396, as well as three mouse models, namely, CD-1, C3H/HeJ, and BALB/c, were evaluated. We were unable to observe B. miyamotoi LB-2001 spirochetes in the blood via darkfield microscopy or to detect DNA via real-time PCR post needle inoculation in the CD-1 and C3H/HeJ mice. However, LB-2001 DNA was detected via real-time PCR in the blood of the BALB/c mice after needle inoculation, although spirochetes were not observed via microscopy. CD-1, C3H/HeJ, and BALB/c mice generated an antibody response to B. miyamotoi LB-2001 following needle inoculation, but established infections were not detected, and the I. scapularis larvae failed to acquire spirochetes from the exposed CD-1 mice. In contrast, B. miyamotoi CT13-2396 was visualized in the blood of the CD-1 and C3H/HeJ mice via darkfield microscopy and detected by real-time PCR post needle inoculation. Both mouse strains seroconverted. However, no established infection was detected in the mouse organs, and the I. scapularis larvae failed to acquire Borrelia after feeding on CT13-2396 exposed CD-1 or C3H/HeJ mice. These findings underscore the challenges in establishing an experimental B. miyamotoi infection model in immunocompetent laboratory mice. IMPORTANCE Borrelia miyamotoi is a causative agent of hard tick relapsing fever, was first identified in the early 1990s, and was characterized as a human pathogen in 2011. Unlike other relapsing fever Borrelia species, B. miyamotoi spread by means of Ixodes ticks. The relatively recent recognition of this human pathogen means that B. miyamotoi is virtually uncharacterized, compared to other Borrelia species. Currently there is no standard mouse-tick model with which to study the interactions of the pathogen within its vector and hosts. We evaluated two B. miyamotoi isolates and three immunocompetent mouse models to identify an appropriate model with which to study tick-host-pathogen interactions. With the increased prevalence of human exposure to Ixodes ticks, having an appropriate model with which to study B. miyamotoi will be critical for the future development of diagnostics and intervention strategies.

17.
J Crohns Colitis ; 17(12): 2033-2036, 2023 Dec 30.
Article in English | MEDLINE | ID: mdl-37422724

ABSTRACT

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.


Subject(s)
Colitis, Ulcerative , Heterocyclic Compounds, 3-Ring , Humans , Infliximab/therapeutic use , Colitis, Ulcerative/surgery , Salvage Therapy , Treatment Outcome , Australia , Steroids/therapeutic use , Colectomy , Retrospective Studies
18.
PLoS One ; 18(2): e0281942, 2023.
Article in English | MEDLINE | ID: mdl-36827340

ABSTRACT

Borrelia miyamotoi is a tick-transmitted spirochete that is genetically grouped with relapsing fever Borrelia and possesses multiple archived pseudogenes that encode variable major proteins (Vmps). Vmps are divided into two groups based on molecular size; variable large proteins (Vlps) and variable small proteins (Vsps). Relapsing fever Borrelia undergo Vmp gene conversion at a single expression locus to generate new serotypes by antigenic switching which is the basis for immune evasion that causes relapsing fever in patients. This study focused on B. miyamotoi vmp expression when spirochetes were subjected to antibody killing selection pressure. We incubated a low passage parent strain with mouse anti-B. miyamotoi polyclonal antiserum which killed the majority population, however, antibody-resistant reisolates were recovered. PCR analysis of the gene expression locus in the reisolates showed vsp1 was replaced by Vlp-encoded genes. Gel electrophoresis protein profiles and immunoblots of the reisolates revealed additional Vlps indicating that new serotype populations were selected by antibody pressure. Sequencing of amplicons from the expression locus of the reisolates confirmed the presence of a predominant majority serotype population with minority variants. These findings confirm previous work demonstrating gene conversion in B. miyamotoi and that multiple serotype populations expressing different vmps arise when subjected to antibody selection. The findings also provide evidence for spontaneous serotype variation emerging from culture growth in the absence of antibody pressure. Validation and determination of the type, number, and frequency of serotype variants that arise during animal infections await further investigations.


Subject(s)
Borrelia , Ixodes , Relapsing Fever , Ticks , Animals , Mice , Borrelia/genetics , Antibodies/genetics , Antigenic Variation
19.
JGH Open ; 7(7): 482-486, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37496810

ABSTRACT

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.

20.
mBio ; 14(2): e0298122, 2023 04 25.
Article in English | MEDLINE | ID: mdl-36976016

ABSTRACT

Outer surface protein C (OspC) plays a pivotal role in mediating tick-to-host transmission and infectivity of the Lyme disease spirochete, Borreliella burgdorferi. OspC is a helical-rich homodimer that interacts with tick salivary proteins, as well as components of the mammalian immune system. Several decades ago, it was shown that the OspC-specific monoclonal antibody, B5, was able to passively protect mice from experimental tick-transmitted infection by B. burgdorferi strain B31. However, B5's epitope has never been elucidated, despite widespread interest in OspC as a possible Lyme disease vaccine antigen. Here, we report the crystal structure of B5 antigen-binding fragments (Fabs) in complex with recombinant OspC type A (OspCA). Each OspC monomer within the homodimer was bound by a single B5 Fab in a side-on orientation, with contact points along OspC's α-helix 1 and α-helix 6, as well as interactions with the loop between α-helices 5 and 6. In addition, B5's complementarity-determining region (CDR) H3 bridged the OspC-OspC' homodimer interface, revealing the quaternary nature of the protective epitope. To provide insight into the molecular basis of B5 serotype specificity, we solved the crystal structures of recombinant OspC types B and K and compared them to OspCA. This study represents the first structure of a protective B cell epitope on OspC and will aid in the rational design of OspC-based vaccines and therapeutics for Lyme disease. IMPORTANCE The spirochete Borreliella burgdorferi is a causative agent of Lyme disease, the most common tickborne disease in the United States. The spirochete is transmitted to humans during the course of a tick taking a bloodmeal. After B. burgdorferi is deposited into the skin of a human host, it replicates locally and spreads systemically, often resulting in clinical manifestations involving the central nervous system, joints, and/or heart. Antibodies directed against B. burgdorferi's outer surface protein C (OspC) are known to block tick-to-host transmission, as well as dissemination of the spirochete within a mammalian host. In this report, we reveal the first atomic structure of one such antibody in complex with OspC. Our results have implications for the design of a Lyme disease vaccine capable of interfering with multiple stages in B. burgdorferi infection.


Subject(s)
Borrelia burgdorferi , Lyme Disease , Ticks , Humans , Animals , Mice , Borrelia burgdorferi/metabolism , Epitopes, B-Lymphocyte/genetics , Lyme Disease Vaccines , Antigens, Bacterial , Lyme Disease/prevention & control , Bacterial Outer Membrane Proteins/chemistry , Mammals/metabolism
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