Differential utilization of CD134 as a functional receptor by diverse strains of feline immunodeficiency virus

The feline homologue of CD134 (fCD134) is the primary binding receptor for feline immunodeficiency virus (FIV), targeting the virus preferentially to activated CD4+ helper T cells. However, with disease progression, the cell tropism of FIV broadens such that B cells and monocytes/macrophages become significant reservoirs of proviral DNA, suggesting that receptor utilization may alter with disease progression. We examined the receptor utilization of diverse strains of FIV and found that all strains tested utilized CD134 as the primary receptor. Using chimeric feline x human CD134 receptors, the primary determinant of receptor function was mapped to the first cysteine-rich domain (CRD1) of fCD134. For the PPR and B2542 strains, the replacement of CDR1 of fCD134 (amino acids 1 to 64) with human CD134 (hCD134) alone was sufficient to confer nearly optimal receptor function. However, evidence of differential utilization of CD134 was revealed, since strains GL8, CPGammer (CPG41), TM2, 0827, and NCSU1 required determinants in the region spanning amino acids 65 to 85, indicating that these strains may require a more stringent interaction for infection to proceed

A comparative exploration of social policy relating to teenage pregnancy in Finland and Scotland

The purpose of this thesis is to comparatively explore a selection of policies relating to teenage pregnancy in Finland and Scotland. Although much comparative research has explored teenage pregnancy and policy relating to it in England with other countries, very little work has explored either the policy situation within Scotland or comparatively explored Scottish policy responses to teenage pregnancy with other countries. Although the trends in teenage pregnancy rates are similar between England and Scotland, there are noted policy differences between the two countries that warrant further exploration of the situation particular to Scotland. Finland presents an interesting comparison for Scotland, in particular due to a number of important constants that exist including; the sexual behaviour rates of young people, the legal age of heterosexual consent and similar ages of first intercourse, and yet considerably lower rates of teenage pregnancy. Between the 1970s and 1980s the rate of teenage pregnancy declined in both Finland and Scotland. Since that time Finland has witnessed further decline, whilst the rate in Scotland has remained relatively unchanged. Utilising a variety of primary and secondary data including in-depth interviews with key personnel at three levels of policy development and implementation: government, local authority/ municipality and schools, as well as policy documentation from both countries, this research has located, mapped and comparatively analysed three areas of policy relating to teenage pregnancy: sex education, sexual health and education. The findings of this research illustrate that policy developed in Finland since the 1970s has taken a pragmatic approach to the prevention of unintended teenage pregnancy, combining sex education provision in a range of core subjects throughout the curriculum at the school level with a national system of school nurses located in school-based clinics. Additionally, the Finnish education system was structured in such a way from 1970 so as to olf"fer a high, level of vocational and academic choice at the school level and actively encourage a high level of continuation beyond the age of sixteen. In relation to policy development in Scotland, the findings of this research illustrate that whilst the foundations for successful future policy development are now present, policy developed prior to the mid-1990s failed to meet the needs of young people in Scotland in relation to the provision of sex education, sexual health services and educational choice at the school level beyond academically orientated examinations. Since the mid-1990s there have been changes in the direction of policy within the areas under exploration. Whilst a level of complacency appears to have set in with regard to the lower level of teenage abortion in Finland, the opposite has been occurring in Scotland, with raised awareness of the sexual health rights and needs of young people being placed at the forefront of policy development. As this thesis has detailed, the various changes have the potential to influence the rates of teenage pregnancy in both countries, negatively in Finland and positively in Scotland. In addition to highlighting potential policy options to aid in the future reduction of unintended teenage pregnancy in Scotland, a better understanding of the relationship that each area of policy has to teenage pregnancy has also been developed within this thesis. The findings contribute to the on-going debate concerning a number of important areas, first, the provision of `effective' sex education, second, the necessity to base sexual health services on the needs of young people and third, the importance that continued education post-16 can play as an indirect means to delaying pregnancy and parenthood

An orthologue of bacteroides fragilis NanH is the principal sialidase in tannerella forsythia

Sialidase activity is a putative virulence factor of the anaerobic periodontal pathogen Tannerella forsythia, but it is uncertain which genes encode this activity. Characterization of a putative sialidase, SiaHI, by others, indicated that this protein alone may not be responsible for all of the sialidase activity. We describe a second sialidase in T. forsythia (TF0035), an orthologue of Bacteroides fragilis NanH, and its expression in Escherichia coli. Sialidase activity of the expressed NanH was confirmed by using 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid as a substrate. Biochemical characterization of the recombinant T. forsythia NanH indicated that it was active over a broad pH range, with optimum activity at pH 5.5. This enzyme has high affinity for 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (Km of 32.9 ± 10.3 μM) and rapidly releases 4-methylumbelliferone (Vmax of 170.8 ± 11.8 nmol of 4-methylumbelliferone min−1 mg of protein−1). E. coli lysates containing recombinant T. forsythia NanH cleave sialic acid from a range of substrates, with a preference for α2-3 glycosidic linkages. The genes adjacent to nanH encode proteins apparently involved in the metabolism of sialic acid, indicating that the NanH sialidase is likely to be involved in nutrient acquisition

Genetic diversity of Brazilian isolates of feline immunodeficiency virus

We isolated Feline immunodeficiency virus (FIV) from three adult domestic cats, originating from two open shelters in Brazil. Viruses were isolated from PBMC following co-cultivation with the feline T-lymphoblastoid cell line MYA-1. All amplified env gene products were cloned directly into pGL8MYA. The nucleic acid sequences of seven clones were determined and then compared with those of previously described isolates. The sequences of all of the Brazilian virus clones were distinct and phylogenetic analysis revealed that all belong to subtype B. Three variants isolated from one cat and two variants were isolated from each of the two other cats, indicating that intrahost diversity has the potential to pose problems for the treatment and diagnosis of FIV infection

Patients' inability to perform a preoperative cardiopulmonary exercise test or demonstrate an anaerobic threshold is associated with inferior outcomes after major colorectal surgery.

BACKGROUND: Surgical patients with poor functional capacity, determined by oxygen consumption at anaerobic threshold (AT) during cardiopulmonary exercise testing (CPET), experience longer hospital stays and worse short- and medium-term survival. However, previous studies excluded patients who were unable to perform a CPET or who failed to demonstrate an AT. We hypothesized that such patients are at risk of inferior outcomes after elective surgery. METHODS: All patients undergoing major colorectal surgery attempted CPET to assist in the planning of care. Patients were stratified by their test results into Fit (AT ≥ 11.0 ml O2 kg(-1) min(-1)), Unfit (AT < 11.0 ml O2 kg(-1) min(-1)), or Unable to CPET groups (failed to pedal or demonstrate an AT). For each group, we determined hospital stay and mortality. RESULTS: Between March 2009 and April 2010, 269 consecutive patients were screened, and proceeded to bowel resection. Median hospital stay was 8 days (IQR 5.1-13.4) and there were 44 deaths (16%) at 2 yr; 26 (9.7%) patients were categorized as Unable to CPET, 69 (25.7%) Unfit and 174 (64.7%) Fit. There were statistically significant differences between the three groups in hospital stay [median (IQR) 14.0 (10.5-23.8) vs 9.9 (5.5-15) vs 7.1 (4.9-10.8) days, P < 0.01] and mortality at 2 yr [11/26 (42%) vs 14/69 (20%) vs 19/174 (11%), respectively (P < 0.01)] although the differences between Unable and Unfit were not statistically different. CONCLUSIONS: Patients' inability to perform CPET is associated with inferior outcomes after major colorectal surgery. Future studies evaluating CPET in risk assessment for major surgery should report outcomes for this subgroup

Selective expansion of viral variants following experimental transmission of a reconstituted feline immunodeficiency virus quasispecies

Following long-term infection with virus derived from the pathogenic GL8 molecular clone of feline immunodeficiency virus (FIV), a range of viral variants emerged with distinct modes of interaction with the viral receptors CD134 and CXCR4, and sensitivities to neutralizing antibodies. In order to assess whether this viral diversity would be maintained following subsequent transmission, a synthetic quasispecies was reconstituted comprising molecular clones bearing envs from six viral variants and its replicative capacity compared in vivo with a clonal preparation of the parent virus. Infection with either clonal (Group 1) or diverse (Group 2) challenge viruses, resulted in a reduction in CD4+ lymphocytes and an increase in CD8+ lymphocytes. Proviral loads were similar in both study groups, peaking by 10 weeks post-infection, a higher plateau (set-point) being achieved and maintained in study Group 1. Marked differences in the ability of individual viral variants to replicate were noted in Group 2; those most similar to GL8 achieved higher viral loads while variants such as the chimaeras bearing the B14 and B28 Envs grew less well. The defective replication of these variants was not due to suppression by the humoral immune response as virus neutralising antibodies were not elicited within the study period. Similarly, although potent cellular immune responses were detected against determinants in Env, no qualitative differences were revealed between animals infected with either the clonal or the diverse inocula. However, in vitro studies indicated that the reduced replicative capacity of variants B14 and B28 in vivo was associated with altered interactions between the viruses and the viral receptor and co-receptor. The data suggest that viral variants with GL8-like characteristics have an early, replicative advantage and should provide the focus for future vaccine development

Making sense of a diagnosis of incurable cancer: The importance of communication

Purpose:  Patients diagnosed with incurable cancer may experience existential distressand difficulty in re-appraising their lives because of uncertainty about the future. Objectives: This study sought to understand how patients living with incurable cancer made sense of their diagnosis, how they prepared for the future and what support they wanted from their health professionals.  Subjects:  27 patients were recruited from the oncology and palliative care service at three metropolitan hospitals. Methods:  A qualitative research approach was used. Semi-structured face-to-face interviews were conducted. Interviews were audio-taped and transcribed verbatim.  Data was analyzed using the constant-comparative method.  Results:  Participants did not express a need to make sense of their diagnosis nor always ascribe to a particular religious belief; rather, many relied on a personal spirituality or philosophy to bring meaning to their experience. Importance was placed on their doctor keeping up with technology, being honest, and being confident and positive. Conclusion:  Participants in this study had incurable cancer but making sense of their current situation was not a conscious priority. For these patients, uncertainty was a positive, as certainty for them indicates death is approaching. What these interviews suggest, from the patient’s perspective, is that there is an implied contract between doctor and patient during this period which involves the doctor managing the flow of difficult information so that the patient can maintain normality for as long as possible. Understanding this helps to explain the difficulty of having advance care planning conversations within this setting, despite the many opportunities that a longer disease trajectory would seem to offer.

Modulation of the virus-receptor interaction by mutations in the V5 loop of feline immunodeficiency virus (FIV) following in vivo escape from neutralising antibody

&lt;b&gt;BACKGROUND:&lt;/b&gt; In the acute phase of infection with feline immunodeficiency virus (FIV), the virus targets activated CD4+ T cells by utilising CD134 (OX40) as a primary attachment receptor and CXCR4 as a co-receptor. The nature of the virus-receptor interaction varies between isolates; strains such as GL8 and CPGammer recognise a "complex" determinant on CD134 formed by cysteine-rich domains (CRDs) 1 and 2 of the molecule while strains such as PPR and B2542 require a more "simple" determinant comprising CRD1 only for infection. These differences in receptor recognition manifest as variations in sensitivity to receptor antagonists. In this study, we ask whether the nature of the virus-receptor interaction evolves in vivo.&lt;p&gt;&lt;/p&gt; &lt;b&gt;RESULTS:&lt;/b&gt; Following infection with a homogeneous viral population derived from a pathogenic molecular clone, a quasispecies emerged comprising variants with distinct sensitivities to neutralising antibody and displaying evidence of conversion from a "complex" to a "simple" interaction with CD134. Escape from neutralising antibody was mediated primarily by length and sequence polymorphisms in the V5 region of Env, and these alterations in V5 modulated the virus-receptor interaction as indicated by altered sensitivities to antagonism by both anti-CD134 antibody and soluble CD134.&lt;p&gt;&lt;/p&gt; &lt;b&gt;CONCLUSIONS:&lt;/b&gt; The FIV-receptor interaction evolves under the selective pressure of the host humoral immune response, and the V5 loop contributes to the virus-receptor interaction. Our data are consistent with a model whereby viruses with distinct biological properties are present in early versus late infection and with a shift from a "complex" to a "simple" interaction with CD134 with time post-infection.&lt;p&gt;&lt;/p&gt

An ATP-binding cassette-type cysteine transporter in Campylobacter jejuni inferred from the structure of an extracytoplasmic solute receptor protein

Campylobacter jejuni is a Gram-negative food-borne pathogen associated with gastroenteritis in humans as well as cases of the autoimmune disease Guillain Barre syndrome. C. jejuni is asaccharolytic because it lacks an active glycolytic pathway for the use of sugars as a carbon source. This suggests an increased reliance on amino acids as nutrients and indeed the genome sequence of this organism indicates the presence of a number of amino acid uptake systems. Cj0982, also known as CjaA, is a putative extracytoplasmic solute receptor for one such uptake system as well as a major surface antigen and vaccine candidate. The crystal structure of Cj0982 reveals a two-domain protein with density in the enclosed cavity between the domains that clearly defines the presence of a bound cysteine ligand. Fluorescence titration experiments were used to demonstrate that Cj0982 binds cysteine tightly and specifically with a K-d of similar to 10(-7) M consistent with a role as a receptor for a high- affinity transporter. These data imply that Cj0982 is the binding protein component of an ABC-type cysteine transporter system and that cysteine uptake is important in the physiology of C. jejuni

The incidence and prevalence of delirium across palliative care settings: A systematic review

© The Author(s) 2019. Background: Delirium is a common and distressing neurocognitive condition that frequently affects patients in palliative care settings and is often underdiagnosed. Aim: Expanding on a 2013 review, this systematic review examines the incidence and prevalence of delirium across all palliative care settings. Design: This systematic review and meta-analyses were prospectively registered with PROSPERO and included a risk of bias assessment. Data sources: Five electronic databases were examined for primary research studies published between 1980 and 2018. Studies on adult, non-intensive care and non-postoperative populations, either receiving or eligible to receive palliative care, underwent dual reviewer screening and data extraction. Studies using standardized delirium diagnostic criteria or valid assessment tools were included. Results: Following initial screening of 2596 records, and full-text screening of 153 papers, 42 studies were included. Patient populations diagnosed with predominantly cancer (n = 34) and mixed diagnoses (n = 8) were represented. Delirium point prevalence estimates were 4%–12% in the community, 9%–57% across hospital palliative care consultative services, and 6%–74% in inpatient palliative care units. The prevalence of delirium prior to death across all palliative care settings (n = 8) was 42%–88%. Pooled point prevalence on admission to inpatient palliative care units was 35% (confidence interval = 0.29–0.40, n = 14). Only one study had an overall low risk of bias. Varying delirium screening and diagnostic practices were used. Conclusion: Delirium is prevalent across all palliative care settings, with one-third of patients delirious at the time of admission to inpatient palliative care. Study heterogeneity limits meta-analyses and highlights the future need for rigorous studies