Physiological and behavioural consequences of network breakdown in brain injury

Traumatic brain injury (TBI) is a major public health problem with a huge unmet need for effective long-term care. Advances in MRI technology using diffusion tensor imaging (DTI) have demonstrated structural abnormalities in patients with TBI, often not seen on conventional brain imaging. The structural and neuropsychological consequences are described in existing research. The aim of this thesis is to identify whether there are physiological and behavioural consequences of TBI, which may be contributing to the observed problems in daily activities associated with this condition. This will help to understand the devastating functional impact following TBI, and its neurorehabilitation needs. This thesis initially develops a study protocol to investigate the physiology in TBI. Initial work explores physiology in thirty four healthy individuals using transcranial magnetic stimulation (TMS) to produce a study protocol that can be used in the patient group. This examined a selection of pathways, including the assessment of callosal physiology using a twin coil TMS method to assess for interhemispheric inhibition. This protocol was used to assess seventeen TBI patients, and compared to healthy controls, and demonstrated that callosal transfer is physiologically different between the two groups. The behavioural consequences of callosal transfer were then explored through the development of a bimanual tapping task in twenty nine healthy participants. The behavioural consequences were then assessed in the same group of TBI patients, and compared to the control group. The TBI patients had comparable mean performance. However, the variability in performance was the main difference between the two groups. The MRI DTI metrics were then investigated in the TBI and control groups. A relationship between the physiology, behaviour and microstructure was then explored. Through this series of investigations this thesis hopes to increase existing understanding of the consequences of brain injury

Reducing Intrathecal Baclofen Related Infections: Service Evaluation and Best Practice Guidelines

Objectives: Intrathecal baclofen (ITB) pumps are an effective treatment for spasticity; however infection rates have been reported in 3–26% of patients in the literature. The multidisciplinary ITB service has been established at The National Hospital for Neurology and Neurosurgery, UCLH, Queen Square, London for over 20 years. Our study was designed to clarify the rate of infection in our ITB patient cohort and secondly, to formulate and implement best practice guidelines and to determine prospectively, whether they effectively reduced infection rates. / Methods: Clinical record review of all patients receiving ITB pre‐intervention; January 2013–May 2015, and following practice changes; June 2016–June 2018. / Results: Four of 118 patients receiving ITB during the first time period (3.4%, annual incidence rate of infection 1.4%) developed an ITB‐related infection (three following ITB pump replacement surgery, one after initial implant). Infections were associated with 4.2% of ITB‐related surgical procedures. Three of four pumps required explantation. Following change in practice (pre‐operative chlorhexidine skin wash and intraoperative vancomycin wash of the fibrous pocket of the replacement site), only one of 160 ITB patients developed infection (pump not explanted) in the second time period (0.6%, annual incidence rate 0.3%). The infection rate related to ITB surgical procedures was 1.1%. In cases of ITB pump replacement, the infection rate was reduced to 3.3% from 17.6%. / Conclusions: This study suggests that a straightforward change in clinical practice may lower infection rates in patients undergoing ITB therapy

A chemical probe based on the PreQ1 metabolite enables transcriptome-wide mapping of binding sites

The role of metabolite-responsive riboswitches in regulating gene expression in bacteria is well known and makes them useful systems for the study of RNA-small molecule interactions. Here, we study the PreQ1 riboswitch system, assessing sixteen diverse PreQ1-derived probes for their ability to selectively modify the class-I PreQ1 riboswitch aptamer covalently. For the most active probe (11), a diazirine-based photocrosslinking analog of PreQ1, X-ray crystallography and gel-based competition assays demonstrated the mode of binding of the ligand to the aptamer, and functional assays demonstrated that the probe retains activity against the full riboswitch. Transcriptome-wide mapping using Chem-CLIP revealed a highly selective interaction between the bacterial aptamer and the probe. In addition, a small number of RNA targets in endogenous human transcripts were found to bind specifically to 11, providing evidence for candidate PreQ1 aptamers in human RNA. This work demonstrates a stark influence of linker chemistry and structure on the ability of molecules to crosslink RNA, reveals that the PreQ1 aptamer/ligand pair are broadly useful for chemical biology applications, and provides insights into how PreQ1, which is similar in structure to guanine, interacts with human RNAs

Mavacamten Treatment for Symptomatic Obstructive Hypertrophic Cardiomyopathy: Interim Results From the MAVA-LTE Study, EXPLORER-LTE Cohort.

This study was funded by Bristol Myers Squibb, Princeton, New Jersey, USA. Bristol Myers Squibb’s policy on data sharing is available online at https://www.bms.com/researchers-and-partners/clinicaltrials-and-research/disclosure-commitment.html. Dr Rader has received consulting fees from Medtronic, Bristol Myers Squibb, and ReCor Medical. Dr Ore˛ziak has received personal fees from Bristol Myers Squibb. Dr Saberi has received personal fees from Bristol Myers Squibb. Dr Fermin has received consulting fees from Alnylam, Eidos Therapeutics, Bristol Myers Squibb, and Pfizer. Dr Wheeler has received personal fees and research support from Bristol Myers Squibb. Dr Garcia-Pavia has received consulting and speaking fees from Bristol Myers Squibb, Rocket Pharmaceuticals, and Cytokinetics and speaking fees from Bristol Myers Squibb and Cytokinetics. Dr Zwas has received personal fees from Bristol Myers Squibb. Dr Masri has received grants from Akcea, Pfizer, and Ultromics and consulting fees from Alnylam, Cytokinetics, Eidos Therapeutics, Ionis, and Pfizer. Dr Owens has received consulting fees from Bristol Myers Squibb, Cytokinetics, and Pfizer. Dr Hegde serves on the faculty of the Cardiovascular Imaging Core Laboratory at Brigham and Women’s Hospital, and her institution has received payments for her consulting work from Bristol Myers Squibb. Dr Seidler has received consulting fees or honoraria for lectures from Bristol Myers Squibb and Cytokinetics. Dr Balaratnam and Dr Sehnert are employees of Bristol Myers Squibb and own stock of Bristol Myers Squibb. Shawna Fox is an employee of IQVIA, a partner providing statistics services to Bristol Myers Squibb. Dr Olivotto has received grants from Amicus, Boston Scientific, Bristol Myers Squibb, Cytokinetics, Genzyme, and Menarini International and consulting fees from Amicus, Cytokinetics, Genzyme, MS Pharma, Rocket Pharmaceuticals, and Tenaya Therapeutics.BACKGROUND Data assessing the long-term safety and efficacy of mavacamten treatment for symptomatic obstructive hypertrophic cardiomyopathy are needed. OBJECTIVES The authors sought to evaluate interim results from the EXPLORER-Long Term Extension (LTE) cohort of MAVA-LTE (A Long-Term Safety Extension Study of Mavacamten in Adults Who Have Completed EXPLORER-HCM; NCT03723655). METHODS After mavacamten or placebo withdrawal at the end of the parent EXPLORER-HCM (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy; NCT03470545), patients could enroll in MAVA-LTE. Patients received mavacamten 5 mg once daily; adjustments were made based on site-read echocardiograms. RESULTS Between April 9, 2019, and March 5, 2021, 231 of 244 eligible patients (94.7%) enrolled in MAVA-LTE (mean age: 60 years; 39% female). At data cutoff (August 31, 2021) 217 (93.9%) remained on treatment (median time in study: 62.3 weeks; range: 0.3-123.9 weeks). At 48 weeks, patients showed improvements in left ventricular outflow tract (LVOT) gradients (mean change ± SD from baseline: resting: -35.6 ± 32.6 mm Hg; Valsalva: -45.3 ± 35.9 mm Hg), N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels (median: -480 ng/L; Q1-Q3: -1,104 to -179 ng/L), and NYHA functional class (67.5% improved by ≥1 class). LVOT gradients and NT-proBNP reductions were sustained through 84 weeks in patients who reached this timepoint. Over 315 patient-years of exposure, 8 patients experienced an adverse event of cardiac failure, and 21 patients had an adverse event of atrial fibrillation, including 11 with no prior history of atrial fibrillation. Twelve patients (5.2%) developed transient reductions in site-read echocardiogram left ventricular ejection fraction of <50%, resulting in temporary treatment interruption; all recovered. Ten patients discontinued treatment due to treatment-emergent adverse events. CONCLUSIONS Mavacamten treatment showed clinically important and durable improvements in LVOT gradients, NT-proBNP levels, and NYHA functional class, consistent with EXPLORER-HCM. Mavacamten treatment was well tolerated over a median 62-week follow-up.S

Fluorescence in situ hybridisation analysis of chromosomal aberrations in gastric tissue: the potential involvement of Helicobacter pylori

In this series of experiments, a novel protocol was developed whereby gastric cells were collected using endoscopic cytology brush techniques, and prepared, such that interphase fluorescence in situ hybridization (FISH) could be performed. In total, 80 distinct histological samples from 37 patients were studied using four chromosome probes (over 32 000 cells analysed). Studies have previously identified abnormalities of these four chromosomes in upper GI tumours. Using premalignant tissues, we aimed to determine how early in Correa's pathway to gastric cancer these chromosome abnormalities occurred. Aneuploidy of chromosomes 4, 8, 20 and 17(p53) was detected in histologically normal gastric mucosa, as well as in gastritis, intestinal metaplasia, dysplasia and cancer samples. The levels of aneuploidy increased as disease severity increased. Amplification of chromosome 4 and chromosome 20, and deletion of chromosome 17(p53) were the more common findings. Hence, a role for these abnormalities may exist in the initiation of, and the progression to, gastric cancer. Helicobactor pylori infection was determined in premalignant tissue using histological analysis and PCR technology. Detection rates were comparable. PCR was used to subtype H. pylori for CagA status. The amplification of chromosome 4 in gastric tissue was significantly more prevalent in H. pylori-positive patients (n=7) compared to H. pylori-negative patients (n=11), possibly reflecting a role for chromosome 4 amplification in H. pylori-induced gastric cancer. The more virulent CagA strain of H. pylori was associated with increased disease pathology and chromosomal abnormalities, although numbers were small (CagA+ n=3, CagA− n=4). Finally, in vitro work demonstrated that the aneuploidy induced in a human cell line after exposure to the reactive oxygen species (ROS) hydrogen peroxide was similar to that already shown in the gastric cancer pathway, and may further strengthen the hypothesis that H. pylori causes gastric cancer progression via an ROS-mediated mechanism

Irreversible sensorineural hearing loss due to clarithromycin

Clarithromycin is a commonly used advanced generation macrolide. This case study reviews a case of an 81 year old woman who developed sensorineural deafness in the right ear after the start of low dose oral clarithromycin for an infective exacerbation of chronic obstructive pulmonary disease. Despite cessation of this drug after only three days, the sensorineural deafness was found to be irreversible. Reversible sensorineural deafness secondary to macrolides has previously been described and evidence in the literature shows that a dose related phenomenon occurs. Research has indicated that transient dysfunction of the outer hair cells could be the possible mechanism. In this case, however, the patient experienced an irreversible sensorineural deafness associated with the start of low dose oral clarithromycin. This is a side effect profile that has not previously been reported