Queuine Analogues Incorporating the 7-Aminomethyl-7-deazaguanine Core: Structure-Activity Relationships in the Treatment of Experimental Autoimmune Encephalomyelitis.

A library of queuine analogues targeting the modification of tRNA isoacceptors for Asp, Asn, His and Tyr catalysed by queuine tRNA ribosyltransferase (QTRT, also known as TGT) was evaluated in the treatment of a chronic multiple sclerosis model: murine experimental autoimmune encephalomyelitis. Several active 7-deazaguanines emerged, together with a structure-activity relationship involving the necessity for a flexible alkyl chain of fixed length.

De-novo designed ß-lysine derivatives can both augment and diminish the proliferation rates of E. coli through the action of Elongation Factor P.

An investigation into the effect of modified ß-lysines on the growth rates of eubacterial cells is reported. It is shown that the effects observed are due to the post translational modification of Elongation Factor P (EFP) with these compounds catalysed by PoxA. PoxA was found to be remarkably promiscuous, which allowed the activity of a wide range of exogenous ß-lysines to be examined. Two chain-elongated ß-lysine derivatives which differ in aminoalkyl chain length by only 2 carbon units exhibited opposing biological activities - one promoting growth and the other retarding it. Both compounds were shown to operate through modification of EFP.

Pre-existing influenza-specific nasal IgA or nasal viral infection does not affect live attenuated influenza vaccine immunogenicity in children.

The United Kingdom has a national immunization programme which includes annual influenza vaccination in school-aged children, using live attenuated influenza vaccine (LAIV). LAIV is given annually, and it is unclear whether repeat administration can affect immunogenicity. Because LAIV is delivered intranasally, pre-existing local antibody might be important. In this study, we analysed banked samples from a study performed during the 2017/18 influenza season to investigate the role of pre-existing influenza-specific nasal immunoglobulin (Ig)A in children aged 6-14 years. Nasopharyngeal swabs were collected prior to LAIV immunization to measure pre-existing IgA levels and test for concurrent upper respiratory tract viral infections (URTI). Oral fluid samples were taken at baseline and 21-28 days after LAIV to measure IgG as a surrogate of immunogenicity. Antibody levels at baseline were compared with a pre-existing data set of LAIV shedding from the same individuals, measured by reverse transcription-polymerase chain reaction. There was detectable nasal IgA specific to all four strains in the vaccine at baseline. However, baseline nasal IgA did not correlate with the fold change in IgG response to the vaccine. Baseline nasal IgA also did not have an impact upon whether vaccine virus RNA was detectable after immunization. There was no difference in fold change of antibody between individuals with and without an URTI at the time of immunization. Overall, we observed no effect of pre-existing influenza-specific nasal antibody levels on immunogenicity, supporting annual immunization with LAIV in children.

The eukaryotic tRNA-guanine transglycosylase enzyme inserts queuine into tRNA via a sequential bi-bi mechanism.

Eukaryotic tRNA-guanine transglycosylase (TGT) - an enzyme recently recognised to be of potential therapeutic importance - catalyses base-exchange of guanine for queuine at the wobble position of tRNAs associated with 4 amino acids via a distinct mechanism to that reported for its eubacterial homologue. The presence of queuine is unequivocally required as a trigger for reaction between the enzyme and tRNA and exhibits cooperativity not seen using guanine as a substrate.

Differences in nasal immunoglobulin A responses to influenza vaccine strains after live attenuated influenza vaccine (LAIV) immunization in children.

Different vaccine strains included in the live attenuated influenza vaccine (LAIV) have variable efficacy. The reasons for this are not clear and may include differences in immunogenicity. We report a Phase IV open-label study on the immunogenicity of a single dose of quadrivalent LAIV (Fluenz™ Tetra) in children during the 2015/16 season, to investigate the antibody responses to different strains. Eligible children were enrolled to receive LAIV; nasal samples were collected before and approximately 4 weeks after immunization. There was a significant increase in nasal immunoglobulin (Ig)A to the H3N2, B/Victoria lineage (B/Brisbane) and B/Yamagata lineage (B/Phuket) components, but not to the H1N1 component. The fold change in nasal IgA response was inversely proportional to the baseline nasal IgA titre for H1N1, H3N2 and B/Brisbane. We investigated possible associations that may explain baseline nasal IgA, including age and prior vaccination status, but found different patterns for different antigens, suggesting that the response is multi-factorial. Overall, we observed differences in immune responses to different viral strains included in the vaccine; the reasons for this require further investigation.

Ethyl-for-methyl substitution enhances the subtype specificity of mecamylamine analogues.

The synthesis of novel mecamylamine analogues is described in which one, two or three of the methyl groups of mecamylamine have been systematically replaced with ethyl groups. Assessment of the compounds highlights that simple ethyl for methyl changes changes to the parent structure can dramatically enhance activity and selectivity towards either the α4ß2 (at the expense of α3ß4) or the α3ß4 (at the expense of α4ß2) nicotinic acetylcholine receptor sub-type as compared to the parent compound.

Discordance in latent tuberculosis (TB) test results in patients with end-stage renal disease.

OBJECTIVES: This natural experiment was designed to assess the impact of exposure to an active case of tuberculosis (TB) on a group of immunosuppressed individuals, with end-stage renal disease over an extended follow-up. STUDY DESIGN: Close contacts of people with sputum smear-positive Mycobacterium tuberculosis are at high risk of infection, particularly immunosuppressed individuals. An infectious TB healthcare worker worked in a renal dialysis unit for a month before diagnosis, with 104 renal dialysis patients, was exposed for ≥8 h. METHODS: Patients were informed and invited for screening 8-10 weeks postexposure. They either underwent standard two-step assessment with tuberculin skin test (TST) and QuantiFERON®-TB Gold (Cellestis GmbH; QFN) interferon-gamma release assay (IGRA) or after consent, enrolled in a study where these two tests were performed simultaneously with T-SPOT®-TB (Oxford Immunotec Ltd; TSPOT). Patients within the study were followed up for 2 years from exposure, with QFN and TSPOT repeated at months 3 and 6 from the first testing. RESULTS: Of 104 exposed individuals, 75 enrolled in the study. There was a high degree of discordance among QFN, TSPOT and TST. This was seen at both the first time point and also over time in subjects who were retested. No patients had active TB at the baseline testing. None received treatment for latent TB infection. Over the following 2 years, no one developed TB disease. CONCLUSION: This study suggests that there is a low risk of progression to active TB in low-incidence countries even in high-risk groups. This plus the degree of the test result discordance emphasises the complexities of managing TB in such settings as it is unclear which of these tests, if any, provides the best diagnostic accuracy.

A new synthesis and preliminary evaluation of some analogues of mecamylamine - a compound with anti-addiction properties.

A new synthesis of mecamylamine - a known anti-hypertensive drug with anti-addictive properties is described. The new route allowed access to two novel analogues whose activity at two nicotinic acetylcholine receptor subtypes was assessed.

A multi-perspective service evaluation exploring tuberculosis contact screening attendance among adults at a North London hospital.

BACKGROUND: Non-attendance at TB contact screening clinics has been highlighted as a common phenomenon across a number of sites during recruitment to the PREDICT TB Study. This has obvious implications for the safety of patients, their communities and for NHS resources. The objective of this study was to explore why adults who have been in contact with TB do, and do not, attend their screening appointment, thereby allowing identification of interventions to reduce non-attendance. METHODS: A multi-method approach was taken using 15 questionnaires with adults who attended for screening, 15 telephone questionnaires with adults who did not attend and in-depth interviews with 8 TB nurses. Interviews were coded to trace emerging descriptive themes, then refined through an iterative process of interpretation and recoding. RESULTS: Findings from the questionnaires and interviews were categorized into three principle themes following analysis: awareness, hospital factors and leadership. These themes deconstruct the complex phenomena of patients' lack of attendance at this TB contact screening service. CONCLUSION: Recommendations related to issues of leadership, outreach services, flexibility of clinic timing and awareness amongst both the local community and GPs were made.

A novel FOXF1 mutation associated with alveolar capillary dysplasia and coexisting colobomas and hemihyperplasia.

Alveolar capillary dysplasia (ACD) is a rare and lethal cause of hypoxic respiratory failure in the neonate. Here we describe a term neonate with ACD that was found with a previously unreported p.Arg86Pro mutation in the FOXF1 (Forkhead Box-F1) gene and coexisting congenital anomalies, including colobomas of the iris and hemihyperplasia. This unique clinical presentation may indicate a novel, yet unconfirmed disease association for mutations in the FOXF1 gene. Rapid mutation analysis in FOXF1 may provide noninvasive early confirmation of ACD in neonates with respiratory failure and can aid in clinical decision making.

Alveolar capillary dysplasia with multiple congenital anomalies and bronchoscopic airway abnormalities.

Alveolar capillary dysplasia is a rare and fatal disease of newborn infants. Here we describe a patient with alveolar capillary dysplasia, multiple congenital anomalies, a novel genetic mutation and previously undocumented airway findings on bronchoscopy. Knowledge of these associations may help diagnose this rare disorder in neonates with hypoxemic respiratory failure.

Active case finding for tuberculosis among high-risk groups in low-incidence countries.

In low-incidence countries, tuberculosis (TB) is now largely concentrated in high-risk groups such as migrants, homeless people, illicit drug users, alcoholics and prisoners. This has led to increased efforts to implement targeted active case finding for TB among specific populations. This review examines the evidence supporting active case finding in migrants and social risk groups, as well as the cost-effectiveness of interventions. While data from observational studies support active case finding in defined high-risk groups, further research to determine the effectiveness of specific tools and the cost-effectiveness of screening strategies is needed to inform evidence-based control methods in low-incidence countries. Inevitably, addressing TB in low-incidence countries will depend on effective disease control in high-burden countries.

Facile synthesis of 3-nitro-2-substituted thiophenes.

A new approach to 3-nitro-2-substituted thiophenes has been developed. Exposure of commercially available 1,4-dithane-2,5-diol to nitroalkenes in the presence of 20% triethylamine results in a tandem Michael-intramolecular Henry reaction to form the corresponding tetrahydrothiophene. Subsequent microwave irradiation on acidic alumina in the presence of chloranil effects the solvent free dehydration and aromatization to form 3-nitro-2-substituted thiophenes cleanly and rapidly. A simple workup procedure removes the requirement for purification by chromatography in most cases.

Evaluation of a diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b vaccine given concurrently with meningococcal group C conjugate vaccine at 2, 3 and 4 months of age.

BACKGROUND AND OBJECTIVE: In view of the possible introduction of diphtheria-tetanus-acellular pertussis-inactivated poliovirus-Haemophilus influenzae type b (DTaP-IPV-Hib, eg Pediacel) vaccine in the UK, a study of the immunogenicity of Pediacel when given with one of two different meningococcal group C conjugate (MCC) vaccines at 2, 3 and 4 months of age was conducted. METHODS: Randomised controlled study in 241 infants. RESULTS: Post vaccination, the proportion of infants with anti-polyribosylribitol phosphate (PRP) levels > or =0.15 microg/ml was 93.2% (95% confidence interval (CI) 86.6 to 96.7) in the Pediacel group compared with 100% (95% CI 96.4 to 100) in the diphtheria-tetanus-whole-cell pertussis-Haemophilus influenzae type b (DTwP-Hib) group. The anti-PRP response was lower in infants receiving either Pediacel or DTwP-Hib when these vaccines were given concomitantly with meningococcal group C conjugate with diphtheria-derived protein CRM(197) as conjugate protein (MCC-CRM) compared with meningococcal group C conjugate with tetanus toxoid as conjugate protein (MCC-TT). For group C meningococcus, the proportion of infants with serum bactericidal antibody (SBA) titre > or =1:8 in the Pediacel group was 99.0% compared with 100% in the DTwP-Hib group. The MCC SBA geometric mean titre (GMT) was lower in those receiving Pediacel with MCC-TT than in those receiving DTwP-Hib with MCC-TT, although all titres were well above the protective threshold. The MCC SBA GMT was similar in those receiving Pediacel and DTwP-Hib and MCC-CRM. Responses to all other vaccine components were equivalent in the two groups. CONCLUSIONS: Pediacel is immunogenic when given at 2, 3 and 4 months of age. Coadministration of MCC vaccine can influence the Hib response, and the MCC response to a tetanus conjugate can be influenced by the nature of the coadministered DTP-Hib vaccine.

Immunogenicity of one, two or three doses of a meningococcal C conjugate vaccine conjugated to tetanus toxoid, given as a three-dose primary vaccination course in UK infants at 2, 3 and 4 months of age with acellular pertussis-containing DTP/Hib vaccine.

Reduction of the number of injections necessary to confer protection in the infant schedule would reduce discomfort, improve cost-effectiveness and create space for the addition of new vaccinations in the future. This study assessed the immunogenicity of one, two or three doses of meningococcal C conjugate vaccine conjugated to tetanus toxoid (MCC-TT) [Neis-VacC] given concomitantly with a combined diphtheria/tetanus/acellular pertussis/Haemophilus influenzae type b -TT conjugate (DTaP-Hib-TT) [Infanrix-Hib] vaccine at 2, 3 and 4 months of age. A total of 106 healthy UK infants were enrolled and randomised into two groups, one in which blood was taken after the first and third dose and the other after the second and third dose. The meningococcal serogroup C serum bactericidal antibody (SBA) geometric mean titre (GMT) rose significantly from post-first dose (491, 95% CI 275, 877) to post-second dose (1052, 95% CI 774, 1433) (p=0.03), with no significant change after the third dose (1024, 95% CI 768, 1366). An SBA titre of >or=8 was achieved by 92% after the first dose and 100% after the second and third doses. The Hib IgG geometric mean concentration (GMC) rose significantly after each dose: post-first (0.14 microg/ml 95% CI 0.10, 0.18), post-second (0.54 microg/ml, 95% CI 0.33, 0.90), post-third (2.04 microg/ml, 95% CI 1.52, 2.74). The Hib GMC after the third dose was higher than reported previously when this DTaP/Hib was given either on its own or concomitantly with a MCC-CRM conjugate vaccine according to the UK 2, 3 and 4 month schedule. This suggests some enhancement of the response to a Hib-TT vaccine by concomitant administration of MCC-TT. These results suggest that a reduced number of doses of MCC-TT would be adequate in infancy if given concomitantly with an acellular pertussis-containing vaccine.

DT5aP-Hib-IPV and MCC vaccines: preterm infants' response to accelerated immunisation.

AIMS: To describe the immune response of preterm infants to combined diphtheria/tetanus/5 component acellular pertussis-Haemophilus influenzae type b inactivated polio vaccine (DT5aP-Hib-IPV) and meningococcal serogroup C conjugate vaccine (MCC) under accelerated schedule. To compare results with term infants immunised with DT5aP-Hib-IPV and with historical data from preterm infants immunised with a DT3 component aP-Hib vaccine. METHODS: Prospective observational study in preterm infants born at <32 weeks gestation with comparison to contemporary cohort of term infants. DT5aP-Hib-IPV and MCC vaccines were given at 2, 3, and 4 months. RESULTS: Fifty preterm infants (mean gestational age 28.5 weeks) completed the study. After three doses of vaccines Hib polysaccharide IgG geometric mean concentration (GMC) was 1.21 microg/ml with 80% > or =0.15 microg/ml; MCC serum bactericidal assay geometric mean titre (GMT) was 1245 with 100% > or =8. All infants achieved protective titres to diphtheria, tetanus, and the three poliovirus types with > or =80% achieving protective rises in IgG against the five pertussis antigens. CONCLUSION: Preterm infants immunised with DT5aP-Hib-IPV and MCC vaccines show IgG responses to Hib and MCC greater than seen historically in both term and preterm infants with a DT3aP-Hib vaccine, and for pertussis antigens and poliovirus type 1 responses similar to that seen in term infants immunised with DT5aP-Hib-IPV. Responses to poliovirus types 2 and 3 are reduced, but all infants achieved protective titres.

Responses to a fourth dose of Haemophilus influenzae type B conjugate vaccine in early life.

OBJECTIVE: To describe the immune response of preterm infants, with a reduced response to primary Haemophilus influenzae type B (Hib) immunisation, to a fourth dose of Hib conjugate vaccine given in early life. DESIGN: Prospective observational study. SETTING: Five Wessex Neonatal Units. PATIENTS: Infants born at < 32 weeks and immunised with three doses of combined acellular pertussis-Hib vaccine, with a Hib IgG geometric mean concentration (GMC) < 1.0 microg/ml after these primary immunisations. INTERVENTIONS: An additional fourth dose of Hib conjugate vaccine given before 1 year of age. Blood taken to assess Hib IgG concentration and avidity after immunisation. MAIN OUTCOME MEASURES: Hib IgG GMC and avidity index. RESULTS: Ninety six infants (mean gestational age at birth 29.1 weeks) received a fourth dose of Hib at a mean age of 7.8 months. Hib IgG GMC after the primary immunisations was 0.17 microg/ml (95% confidence interval (CI) 0.14 to 0.20) rising to 4.68 microg/ml (95% CI 3.36 to 6.57) after the fourth dose (p < 0.0001). The IgG response to the fourth dose correlated positively with the response after the primary immunisations (p < 0.001). Hib IgG geometric mean avidity index (GMAI) after the primary immunisations was 30.87 (95% CI 20.40 to 46.73). This increased to 124.73 (95% CI 109.93 to 141.51) after the fourth dose (p < 0.0001). CONCLUSION: Preterm infants with very low IgG responses to Hib after primary immunisations with a combined acellular pertussis-Hib vaccine mount a good response to a fourth dose of Hib. This study suggests that all infants will benefit from a fourth dose of Hib, regardless of the age at which it is given.

Acellular pertussis vaccine given by accelerated schedule: response of preterm infants.

OBJECTIVE: To describe the immune response of preterm infants to a diphtheria/tetanus/three component acellular pertussis (DTaP) vaccine, under an accelerated schedule, and the effects of steroids on this response. To compare responses with those of term infants. DESIGN: Prospective observational study. SETTING: Five Wessex neonatal units; Hertfordshire immunisation clinics. PATIENTS: Infants born at < 32 weeks; term controls. INTERVENTIONS: DTaP-Haemophilus influenzae type b vaccine given at 2, 3, and 4 months. Blood taken to assess antibody responses to vaccines. MAIN OUTCOME MEASURES: IgG geometric mean concentrations (GMC) to vaccines. RESULTS: A total of 130 preterm (mean gestational age 29.1 weeks) and 54 term infants were recruited. After the third immunisation, preterm infants had similar GMCs to controls to diphtheria, tetanus, filamentous haemagglutinin (FHA), and pertactin (PRN), but a significantly lower GMC to pertussis toxin (PT). Responses to tetanus and PRN increased with age at the third immunisation, and those to tetanus, FHA, PRN, and PT increased with gestational age at birth. Response to tetanus correlated negatively with the number of doses of antenatal steroids received. There was no association between responses and postnatal steroids. CONCLUSION: When immunised with a combined acellular pertussis- H influenzae type b vaccine under an accelerated schedule, IgG GMC of preterm infants to PT was reduced. GMCs to tetanus, FHA, PRN, and PT increased with gestational age at birth, and GMCs to tetanus and PRN increased with age at the third immunisation. There is, however, no benefit in delaying immunisation. Anti-tetanus IgG decreased with increasing number of doses of antenatal steroids. There was no effect for postnatal steroids.