Analysis of retinotectal regeneration in goldfish using polar dimensions: temporal sequence and spatial order

Quantitative analysis of electrophysiological visuotectal maps using polar dimensions demonstrated uniform representation of visual field on goldfish optic tectum, with topography equally precise in normal and "mature" regenerated projections. The precision of circumferential topography exceeds and is not correlated with that of radial. Radial orderliness may he poor without diminution of circumferential order: these two dimensions of pattern could he generated separately from each other. The method of analysis also allows quantitation of the orientation of the retinotectal projection. During development radial retinotopy in the sequence of axon growth could contribute to radial topography by confining optic terminals to specific annuli within the projection. The possibility of pattern formation by this means during regeneration was studied by examining the sequence of fibre growth by retrograde labelling of ganglion cells with horseradish peroxidase (HRP), applied to a cut through the optic tract at successive intervals after optic nerve transection in mid-orbit. Most results indicated a central-to-peripheral sequence of regeneration; others showed absence of retinotopic sequence. Regeneration of axons from central retina was delayed by repetition of axotomy. Subsequent visuotectal maps were either normal or included electrophysiologically weak representation of central visual field on peripheral tectum, outside or superimposed upon the map of peripheral field. Some of the abnormal maps also contained normal representation of central field on central tectum. Because of the contradictions in these results, the influence of temporal sequence on spatial order of connections remains uncertain. Formation of circumferential topography was investigated by anterograde tracing with HRP of axons from narrow sectors of retina in normal and regenerated pathways. Juxtaposition of labelled axons appears to be completely lost in the optic chiasm or at the site of optic nerve transection. Contact guidance of axons therefore cannot explain circumferential order in the map. Labelling was inadequate to show whether regenerating fibres resegregate retinotopically in the optic tract

Reflections on a crisis: political disenchantment, moral desolation, and political integrity

Declining levels of political trust and voter turnout, the shift towards populist politics marked by appeals to ‘the people’ and a rejection of ‘politics-as-usual’, are just some of the commonly cited manifestations of our culture of political disaffection. Democratic politics, it is argued, is in crisis. Whilst considerable energy has been expended on the task of lamenting the status of our politics and pondering over recommendations to tackle this perceived crisis, amid this raft of complaints and solutions lurks confusion. This paper seeks to explore the neglected question of what the precise nature of the crisis with which we are confronted involves, and, in so doing, to go some way towards untangling our confusion. Taking my cue from Machiavelli and his value-pluralist heirs, I argue that there is a rift between a morally admirable and a virtuous political life. Failure to appreciate this possibility causes narrations of crisis to misconstrue the moral messiness of politics in ways that lead us to misunderstand how we should respond to disenchantment. Specifically, I suggest that: (i) we think that there is a moral crisis in politics because we have an unsatisfactorily idealistic understanding of political integrity in the first place; and (ii) it is a mistake to imagine that the moral purification of politics is possible or desirable. Put simply, our crisis is not moral per se but primarily philosophical in nature: it relates to the very concepts we employ—the qualities of character and context we presuppose whilst pondering over political integrity

Thiopurine monotherapy is effective in ulcerative colitis but significantly less so in Crohn’s disease: long-term outcomes for 11 928 patients in the UK inflammatory bowel disease bioresource

Objective: Thiopurines are widely used as maintenance therapy in inflammatory bowel disease (IBD) but the evidence base for their use is sparse and their role increasingly questioned. Using the largest series reported to date, we assessed the long-term effectiveness of thiopurines in ulcerative colitis (UC) and Crohn’s disease (CD), including their impact on need for surgery. Design: Outcomes were assessed in 11 928 patients (4968 UC, 6960 CD) in the UK IBD BioResource initiated on thiopurine monotherapy with the intention of maintaining medically induced remission. Effectiveness was assessed retrospectively using patient-level data and a definition that required avoidance of escalation to biological therapy or surgery while on thiopurines. Analyses included overall effectiveness, time-to-event analysis for treatment escalation and comparison of surgery rates in patients tolerant or intolerant of thiopurines. Results: Using 68 132 patient-years of exposure, thiopurine monotherapy appeared effective for the duration of treatment in 2617/4968 (52.7%) patients with UC compared with 2378/6960 (34.2%) patients with CD (p<0.0001). This difference was corroborated in a multivariable analysis: after adjusting for variables including treatment era, thiopurine monotherapy was less effective in CD than UC (OR 0.47, 95% CI 0.43 to 0.51, p<0.0001). Thiopurine intolerance was associated with increased risk of surgery in UC (HR 2.44, p<0.0001); with a more modest impact on need for surgery in CD (HR=1.23, p=0.0015). Conclusion: Thiopurine monotherapy is an effective long-term treatment for UC but significantly less effective in CD

Health, education, and social care provision after diagnosis of childhood visual disability

Aim: To investigate the health, education, and social care provision for children newly diagnosed with visual disability.Method: This was a national prospective study, the British Childhood Visual Impairment and Blindness Study 2 (BCVIS2), ascertaining new diagnoses of visual impairment or severe visual impairment and blindness (SVIBL), or equivalent vi-sion. Data collection was performed by managing clinicians up to 1-year follow-up, and included health and developmental needs, and health, education, and social care provision.Results: BCVIS2 identified 784 children newly diagnosed with visual impairment/SVIBL (313 with visual impairment, 471 with SVIBL). Most children had associated systemic disorders (559 [71%], 167 [54%] with visual impairment, and 392 [84%] with SVIBL). Care from multidisciplinary teams was provided for 549 children (70%). Two-thirds (515) had not received an Education, Health, and Care Plan (EHCP). Fewer children with visual impairment had seen a specialist teacher (SVIBL 35%, visual impairment 28%, χ2p < 0.001), or had an EHCP (11% vs 7%, χ2p < 0 . 01).Interpretation: Families need additional support from managing clinicians to access recommended complex interventions such as the use of multidisciplinary teams and educational support. This need is pressing, as the population of children with visual impairment/SVIBL is expected to grow in size and complexity.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

The impact of immediate breast reconstruction on the time to delivery of adjuvant therapy: the iBRA-2 study

Background: Immediate breast reconstruction (IBR) is routinely offered to improve quality-of-life for women requiring mastectomy, but there are concerns that more complex surgery may delay adjuvant oncological treatments and compromise long-term outcomes. High-quality evidence is lacking. The iBRA-2 study aimed to investigate the impact of IBR on time to adjuvant therapy. Methods: Consecutive women undergoing mastectomy ± IBR for breast cancer July–December, 2016 were included. Patient demographics, operative, oncological and complication data were collected. Time from last definitive cancer surgery to first adjuvant treatment for patients undergoing mastectomy ± IBR were compared and risk factors associated with delays explored. Results: A total of 2540 patients were recruited from 76 centres; 1008 (39.7%) underwent IBR (implant-only [n = 675, 26.6%]; pedicled flaps [n = 105,4.1%] and free-flaps [n = 228, 8.9%]). Complications requiring re-admission or re-operation were significantly more common in patients undergoing IBR than those receiving mastectomy. Adjuvant chemotherapy or radiotherapy was required by 1235 (48.6%) patients. No clinically significant differences were seen in time to adjuvant therapy between patient groups but major complications irrespective of surgery received were significantly associated with treatment delays. Conclusions: IBR does not result in clinically significant delays to adjuvant therapy, but post-operative complications are associated with treatment delays. Strategies to minimise complications, including careful patient selection, are required to improve outcomes for patients

Safety, immunogenicity, and reactogenicity of BNT162b2 and mRNA-1273 COVID-19 vaccines given as fourth-dose boosters following two doses of ChAdOx1 nCoV-19 or BNT162b2 and a third dose of BNT162b2 (COV-BOOST): a multicentre, blinded, phase 2, randomised trial

Background Some high-income countries have deployed fourth doses of COVID-19 vaccines, but the clinical need, effectiveness, timing, and dose of a fourth dose remain uncertain. We aimed to investigate the safety, reactogenicity, and immunogenicity of fourth-dose boosters against COVID-19.Methods The COV-BOOST trial is a multicentre, blinded, phase 2, randomised controlled trial of seven COVID-19 vaccines given as third-dose boosters at 18 sites in the UK. This sub-study enrolled participants who had received BNT162b2 (Pfizer-BioNTech) as their third dose in COV-BOOST and randomly assigned them (1:1) to receive a fourth dose of either BNT162b2 (30 µg in 0·30 mL; full dose) or mRNA-1273 (Moderna; 50 µg in 0·25 mL; half dose) via intramuscular injection into the upper arm. The computer-generated randomisation list was created by the study statisticians with random block sizes of two or four. Participants and all study staff not delivering the vaccines were masked to treatment allocation. The coprimary outcomes were safety and reactogenicity, and immunogenicity (antispike protein IgG titres by ELISA and cellular immune response by ELISpot). We compared immunogenicity at 28 days after the third dose versus 14 days after the fourth dose and at day 0 versus day 14 relative to the fourth dose. Safety and reactogenicity were assessed in the per-protocol population, which comprised all participants who received a fourth-dose booster regardless of their SARS-CoV-2 serostatus. Immunogenicity was primarily analysed in a modified intention-to-treat population comprising seronegative participants who had received a fourth-dose booster and had available endpoint data. This trial is registered with ISRCTN, 73765130, and is ongoing.Findings Between Jan 11 and Jan 25, 2022, 166 participants were screened, randomly assigned, and received either full-dose BNT162b2 (n=83) or half-dose mRNA-1273 (n=83) as a fourth dose. The median age of these participants was 70·1 years (IQR 51·6–77·5) and 86 (52%) of 166 participants were female and 80 (48%) were male. The median interval between the third and fourth doses was 208·5 days (IQR 203·3–214·8). Pain was the most common local solicited adverse event and fatigue was the most common systemic solicited adverse event after BNT162b2 or mRNA-1273 booster doses. None of three serious adverse events reported after a fourth dose with BNT162b2 were related to the study vaccine. In the BNT162b2 group, geometric mean anti-spike protein IgG concentration at day 28 after the third dose was 23 325 ELISA laboratory units (ELU)/mL (95% CI 20 030–27 162), which increased to 37 460 ELU/mL (31 996–43 857) at day 14 after the fourth dose, representing a significant fold change (geometric mean 1·59, 95% CI 1·41–1·78). There was a significant increase in geometric mean anti-spike protein IgG concentration from 28 days after the third dose (25 317 ELU/mL, 95% CI 20 996–30 528) to 14 days after a fourth dose of mRNA-1273 (54 936 ELU/mL, 46 826–64 452), with a geometric mean fold change of 2·19 (1·90–2·52). The fold changes in anti-spike protein IgG titres from before (day 0) to after (day 14) the fourth dose were 12·19 (95% CI 10·37–14·32) and 15·90 (12·92–19·58) in the BNT162b2 and mRNA-1273 groups, respectively. T-cell responses were also boosted after the fourth dose (eg, the fold changes for the wild-type variant from before to after the fourth dose were 7·32 [95% CI 3·24–16·54] in the BNT162b2 group and 6·22 [3·90–9·92] in the mRNA-1273 group).Interpretation Fourth-dose COVID-19 mRNA booster vaccines are well tolerated and boost cellular and humoral immunity. Peak responses after the fourth dose were similar to, and possibly better than, peak responses after the third dose

An investigation into the viability of an infrared diagnostic instrument for measurement of CO₂ isotope ratios in breath

Stable CO2 isotope ratio breath tests are established as a valuable tool in diagnostic and investigative medicine, with the potential to become more prominent in the future. The instrument conventionally used to measure the very small changes involved is an Isotope Ratio Mass Spectrometer however, the expense and complexity of such an instrument severely restricts the widespread and routine use of isotopic breath tests. Hence, to realise their full potential an alternative technique is required which is reliable, insensitive to environmental and component fluctuations, uncomplicated and affordable. We present a system that satisfies these criteria using broadband, non-dispersive, ground-state absorption infrared spectroscopy. Two isotopically distinct channels are created and their basal path length ratio recorded at the condition of transmitted intensity equilibrium. The change in channel path length ratios required to restore equilibrium in the 13C-enriched breath sample is directly related to the change in 13CO2 / 12CO2 concentration ratio. The system's novelty lies in this negative feedback loop balancing the signal by means of adjusting the path length of one of the channels. There is little evidence in the literature on infrared breath measurements that the possibility of interference from coincident infrared active breath trace compounds or various spectral effects that could lead to spurious results have been adequately assessed. Therefore, prior to the construction of a prototype instrument based upon this technique the question of its validity must be addressed. Furthermore, in addition to any instrument presenting a viable alternative it should also offer better reliability, long term stability and ideally be of lower cost than other emergent infrared instruments. Significant emphasis has therefore been placed upon evaluation of possible interferents, with the intention of providing an unambiguous assurance of the measurement's validity over a range of conceivable operating conditions and establishing operating tolerances that improve reliability over other infrared techniques. Also the prospect of using this technique to perform alternative isotope ratio breath tests was explored with the feasibility of using a novel filtering technique to enable measurement of 18O12C16O / 13C16O2 being investigated further. These aims were accomplished through the thorough evaluation of literature on breath trace compound's infrared spectra and by a series of theoretical computer instrument simulations, using detailed modelling of a breath sample's CO2 spectroscopy, capable of identifying, evaluating and quantifying the risks posed to a reliable measurement of 13CO2 / 12CO2 due to various spectral effects. The breath trace compound analysis revealed that 13C16O2 / 12C16O2 ratios can confidently be measured for isotopic breath tests using an instrument based on infrared absorption, the position of CO2's ν3 absorption band precluding any discernible risk. From the instrument simulations it has been possible to establish operating tolerances required to avoid or limit the generation of a spurious results and determine parameters necessary for the instrument's construction. Thus, we conclude that through the merits of its design and compliance to operating tolerances established the instrument described presents a viable alternative for providing highly accurate, reliable and low cost breath tests capable of being performed outside of a laboratory environment