The role of endogenous annexin A1 on leukocyte biology

PhDInflammation is the body's innate immune response to the damage caused to its cells and vascularised tissue, either by injury or microbial pathogens. Although these processes cause pain, swelling, redness and an increase in body temperature, inflammation is generally a beneficial salutary response. Since the 1940's glucocorticoids have been widely prescribed in treating inflammatory diseases, e. g. for inflammatory bowel disease and anaphylactic shock hydrocortisone is prescribed, whereas for asthma and rheumatic disease, betametasone and prednisolone are the drugs of choice. During the late 1970's and early 1980's a novel glucocorticoid regulated protein, termed annexin Al, was identified. This protein mediates and shares many of the anti-inflammatory and prostaglandin suppressive properties with glucocorticoids. More recently annexin Al has been shown to be an endogenous ligand for the fMLP receptor, termed the FPR. This thesis questions the fundamental basis of annexin Al leukocyte biology by examining the behaviour of neutrophils and macrophages collected from mice lacking either the protein or its receptor. The major finding in this thesis can be divided into two sections, focusing on the neutrophil activation or the macrophage phagocytosis. Neutrophils from FPR deficient mice could be activated at high concentrations with fMLP, and pre-incubating cells with either the annexin Al mimetic or the FPR antagonist Boc 2 abrogates these effects. Blood neutrophils purified from annexin Al null mice were more susceptible to inflammatory stimuli, causing an excessive increase in cell adhesion molecule expression, chemotaxis and ROS production, compared to littermate (wild type) controls. In contrast neutrophils over expressing this protein exhibited an attenuated degree of activation. Annexin Al null peritoneal macrophages exhibited defects in phagocytosis in a stimulus-specific manner. Annexin Al null macrophages incubated with non-opsonised zymosan, Neisseria or opsonised sheep red blood cells exhibited a grossly impaired uptake of particles. This was further confirmed by electron and confocal microscopy analysis. Furthermore, specific alterations in annexin Al null macrophage plasma 2 membrane CD1lb and F4/80 expression was observed in macrophages lacking this protein. Upon activation these macrophages synthesised an augmented concentration of proinflammatory cytokines. Annexin Al null macrophages were resistant to glucocorticoid inhibition during phagocytosis. These results suggest that the participation of endogenous annexin Al during phagocytosis is critical. In summary, this thesis has investigated for the first time in genetically modified mice the potential effects that the lack of annexin Al may have on specific cellular functions with a major impact on the inflammatory response, finding that indeed this protein exerts a tonic inhibitory action, in a stimulus- and cell-specific fashion, on leukocyte biology

Efek Aplikasi Sodium Fluoride 5% + Tri Calcium Phosphate Terhadap Mikroporositas Permukaan Enamel Gigi Insisive Sulung (In Vitro)

Latar belakang: Sodium Fluoride 5%+Tri Calcium Phosphate adalah salah satu bahan topical fluoride yang dapat menghambat terjadinya demineralisasi dan meningkatkan remineralisasi. Bahan ini aplikasinya harus kontak dengan saliva agar ion-ion kalsium, fosfat dan fluoride tersebut aktif. Tujuan: Untuk meneliti efek aplikasi bahan Sodium Fluoride 5%+Tri Calcium Phosphate terhadap mikroporositas permukaan enamel gigi insisif sulung setelah demineralisasi. Metode: Empat mahkota gigi insisif sulung bawah dipotong secara vertikal, kemudian dibagi menjadi dua kelompok. Kelompok pertama, empat mahkota gigi tersebut dimasukkan ke dalam saliva buatan. Kelompok kedua dilakukan aplikasi bahan Sodium Fluoride 5%+Tri Calcium Phosphate pada bagian enamel gigi lalu dimasukkan ke dalam saliva buatan. Setelah 24 jam, kedua sampel dimasukkan ke dalam larutan demineralisasi (asam asetat 1M) 5 ml selama 3 hari. Setelah di inkubasi, sampel gigi dianalisa menggunakan Scanning Electron Microscope (Hitachi, TM 3000, Jepang). Hasil: Gigi insisif sulung yang diberi perlakuan bahan Sodium Fluoride 5%+Tri Calcium Phosphate didapatkan gambaran porus yang sedikit daripada kelompok kontrol. Simpulan: Pengulasan bahan Sodium Fluoride 5%+Tri Calcium Phosphate mengurangi mikroporositas pada gigi sulung. Kata kunci: Sodium fluoride, Tri Calcium Phosphate, Enamel, gigi sulung

Mouse Dendritic Cells Pulsed with Capsular Polysaccharide Induce Resistance to Lethal Pneumococcal Challenge: Roles of T Cells and B Cells

Mice are exceedingly sensitive to intra-peritoneal (IP) challenge with some virulent pneumococci (LD50 = 1 bacterium). To investigate how peripheral contact with bacterial capsular polysaccharide (PS) antigen can induce resistance, we pulsed bone marrow dendritic cells (BMDC) of C57BL/6 mice with type 4 or type 3 PS, injected the BMDC intra-foot pad (IFP) and challenged the mice IP with supra-lethal doses of pneumococci. We examined the responses of T cells and B cells in the draining popliteal lymph node and measured the effects on the bacteria in the peritoneum and blood. We now report that: 1) The PS co-localized with MHC molecules on the BMDC surface; 2) PS-specific T and B cell proliferation and IFNγ secretion was detected in the draining popliteal lymph nodes on day 4; 3) Type-specific resistance to lethal IP challenge was manifested only after day 5; 4) Type-specific IgM and IgG antibodies were detected in the sera of only some of the mice, but B cells were essential for resistance; 5) Control mice vaccinated with a single injection of soluble PS did not develop a response in the draining popliteal lymph node and were not protected; 6) Mice injected with unpulsed BMDC also did not resist challenge: In unprotected mice, pneumococci entered the blood shortly after IP inoculation and multiplied exponentially in both blood and peritoneum killing the mice within 20 hours. Mice vaccinated with PS-pulsed BMDC trapped the bacteria in the peritoneum. The trapped bacteria proliferated exponentially IP, but died suddenly at 18–20 hours. Thus, a single injection of PS antigen associated with intact BMDC is a more effective vaccine than the soluble PS alone. This model system provides a platform for studying novel aspects of PS-targeted vaccination

Online mindfulness stress intervention for family carers of children and adults with intellectual disabilities : feasibility randomized controlled trial

Objectives: Family carers of people with intellectual disabilities (ID) are twice as likely as other carers to experience stress and mental ill-health, but research exploring interventions is sparse. Online mindfulness may provide an accessible, cost-effective resource. The addition of guided telephone support could help to tailor an existing intervention for this population. A feasibility randomized controlled trial (RCT) was conducted to inform the development of a definitive RCT. Methods: Sixty participants were randomized to complete Be Mindful (a brief online mindfulness intervention) either with or without additional Peer Mentor support. Feasibility of recruitment, retention, intervention adherence, and acceptability of study design were examined. Preliminary analyses were undertaken on participant-reported outcomes pre- and post-intervention. Eighteen semi-structured interviews were conducted as a process evaluation. Results: Feasibility outcomes indicate that it would be possible to recruit and retain (88%) participants to a definitive RCT, and that the study design and intervention are acceptable. The addition of guided telephone support was not burdensome; indeed, it was additionally motivating. Telephone support can be delivered with high fidelity, but this is inconsistent and requires further piloting. Preliminary comparison data indicate small, but non-significant, improvements for participants receiving guided telephone support relative to those who did not over time. Conclusions: It is feasible to deliver online mindfulness with additional telephone guided support to family carers of people with ID, and this may lead to small benefits over receiving online mindfulness alone. A definitive RCT can be planned to examine the effectiveness and cost-effectiveness of this intervention

Malawi District Energy Officer Blueprint : Recommendations Paper

This recommendations paper outlines the proposed role of District Energy Officers (DEOs) in Malawi as a conduit for the Government of Malawi to facilitate the decentralisation of a sustainable energy policy to district level. If developed sensitively and effectively and resourced appropriately, the implementation of DEOs in Malawi could help to strengthen levels of community ownership and empowerment; achieved through energy initiatives, improved communication and networking around energy issues at district level, electricity access development at district level and enhanced electricity literacy through roles in sensitisation and dissemination of knowledge of decentralised energy technologies and processes This paper confirms the Government of Malawi’s proposal that the introduction of an effective DEO programme will assist the Government in decentralisation of its national renewable energy strategy while aligning renewable electricity development with key national energy use targets ; 20% of national energy generation from renewable energy sources and a reduction of 22% in biomass usage by 2025. A decentralised DEO role, working within a centralised management and financial structure is supported by this recommendations paper as an effective methodology for energy decentralisation in Malawi. The support structure and accountability structure outlined in this recommendations paper can be used by the Government of Malawi to empower rural communities in Malawi in taking ownership of their energy sources and their energy use, primarily through design and support of community based development. DEOs act to improve community livelihoods through an increase in local earning potential and co-constructively act to improve national energy security and poverty alleviation across all districts of Malawi

MACHOS: Markov clusters of homologous subsequences

Motivation: The classification of proteins into homologous groups (families) allows their structure and function to be analysed and compared in an evolutionary context. The modular nature of eukaryotic proteins presents a considerable challenge to the delineation of families, as different local regions within a single protein may share common ancestry with distinct, even mutually exclusive, sets of homologs, thereby creating an intricate web of homologous relationships if full-length sequences are taken as the unit of evolution. We attempt to disentangle this web by developing a fully automated pipeline to delineate protein subsequences that represent sensible units for homology inference, and clustering them into putatively homologous families using the Markov clustering algorithm

Health-related Quality of Life in Pediatric Patients With Chronic Hepatitis B Living in the United States and Canada

OBJECTIVES: The aim of the study was to determine whether selected sociodemographic and hepatitis B virus (HBV)-specific clinical factors are associated with health-related quality of life (HRQoL) among pediatric patients chronically infected with HBV. METHODS: Children with chronic HBV enrolled in the Hepatitis B Research Network completed the Child Health Questionnaire at study entry. Caregivers of children 5 to <10 years completed the parent-reported form (CHQ-Parent Report Form); youth 10 to <18 years completed the child-reported CHQ-Child Report Form. We examined univariable associations of the Child Health Questionnaire scores with selected independent variables: sex, adoption status, maternal education, alanine aminotransferase (U/L), aspartate aminotransferase-to-platelet ratio index, and HBV-specific symptom count. RESULTS: A total of 244 participants (83 young children 5-<10 years, 161 youth 10-<18 years) were included, all HBV treatment-naïve. Among young children, increased alanine aminotransferase level was negatively associated with CHQ-Parent Report Form psychosocial summary t score (r = -0.28, P = 0.01). No other subscale comparisons for young children were statistically significant. Among youth, adoption was associated with better physical functioning and general health (P < 0.01). Higher maternal education was associated with better role/functioning-physical and -emotional scores (P < 0.05). Maternal education and adoption status were linked with adoption associated with higher maternal education. Increased symptom count in youth was associated with worse HRQoL in subscales measuring bodily pain, behavior, mental health, and self-esteem (P < 0.01). CONCLUSIONS: Although overall HRQoL is preserved in children with chronic HBV, some sociodemographic and HBV-related clinical factors were associated with impaired HRQoL in our pediatric patients at baseline. Measurement of HRQoL can focus resources on education and psychosocial support in children and families most in need

Seeing the forest for the trees: using the Gene Ontology to restructure hierarchical clustering

Motivation: There is a growing interest in improving the cluster analysis of expression data by incorporating into it prior knowledge, such as the Gene Ontology (GO) annotations of genes, in order to improve the biological relevance of the clusters that are subjected to subsequent scrutiny. The structure of the GO is another source of background knowledge that can be exploited through the use of semantic similarity

Antibiotic Resistant Bloodstream Infections in Pediatric Patients Receiving Chemotherapy or Hematopoietic Stem Cell Transplant: Factors Associated with Development of Resistance, Intensive Care Admission and Mortality

Bloodstream infections (BSI) are a severe complication of antineoplastic chemotherapy or hematopoietic stem cell transplantation (HSCT), especially in the presence of antibiotic resistance (AR). A multinational, multicenter retrospective study in patients aged ≤ 18 years, treated with chemotherapy or HSCT from 2015 to 2017 was implemented to analyze AR among non-common skin commensals BSI. Risk factors associated with AR, intensive care unit (ICU) admission and mortality were analyzed by multilevel mixed effects or standard logistic regressions. A total of 1291 BSIs with 1379 strains were reported in 1031 patients. Among Gram-negatives more than 20% were resistant to ceftazidime, cefepime, piperacillin-tazobactam and ciprofloxacin while 9% was resistant to meropenem. Methicillin-resistance was observed in 17% of S. aureus and vancomycin resistance in 40% of E. faecium. Previous exposure to antibiotics, especially to carbapenems, was significantly associated with resistant Gram-negative BSI while previous colonization with methicillin-resistant S. aureus was associated with BSI due to this pathogen. Hematological malignancies, neutropenia and Gram-negatives resistant to >3 antibiotics were significantly associated with higher risk of ICU admission. Underlying disease in relapse/progression, previous exposure to antibiotics, and need of ICU admission were significantly associated with mortality. Center-level variation showed a greater impact on AR, while patient-level variation had more effect on ICU admission and mortality. Previous exposure to antibiotics or colonization by resistant pathogens can be the cause of AR BSI. Resistant Gram-negatives are significantly associated with ICU admission and mortality, with a significant role for the treating center too. The significant evidence of center-level variations on AR, ICU admission and mortality, stress the need for careful local antibiotic stewardship and infection control programs