Immunological and Structural Characterization of Titin Main Immunogenic Region; I110 Domain Is the Target of Titin Antibodies in Myasthenia Gravis.

Myasthenia gravis (MG) is an autoimmune disease caused by antibodies targeting the neuromuscular junction (NJ) of skeletal muscles. The major MG autoantigen is nicotinic acetylcholine receptor. Other autoantigens at the NJ include MuSK, LRP4 and agrin. Autoantibodies to the intra-sarcomeric striated muscle-specific gigantic protein titin, although not directed to the NJ, are invaluable biomarkers for thymoma and MG disease severity. Thymus and thymoma are critical in MG mechanisms and management. Titin autoantibodies bind to a 30 KDa titin segment, the main immunogenic region (MIR), consisting of an Ig-FnIII-FnIII 3-domain tandem, termed I109-I111. In this work, we further resolved the localization of titin epitope(s) to facilitate the development of more specific anti-titin diagnostics. For this, we expressed protein samples corresponding to 8 MIR and non-MIR titin fragments and tested 77 anti-titin sera for antibody binding using ELISA, competition experiments and Western blots. All anti-MIR antibodies were bound exclusively to the central MIR domain, I110, and to its containing titin segments. Most antibodies were bound also to SDS-denatured I110 on Western blots, suggesting that their epitope(s) are non-conformational. No significant difference was observed between thymoma and non-thymoma patients or between early- and late-onset MG. In addition, atomic 3D-structures of the MIR and its subcomponents were elucidated using X-ray crystallography. These immunological and structural data will allow further studies into the atomic determinants underlying titin-based autoimmunity, improved diagnostics and how to eventually treat titin autoimmunity associated co-morbidities.

Health-Related Quality of Life Among Patients With HR+/HER2- Early Breast Cancer.

PURPOSE: The goal of this study was to characterize health-related quality of life (HRQOL) among patients diagnosed with early-stage, hormone receptor-positive (HR+)/human epidermal growth factor receptor 2 negative (HER2-) breast cancer. METHODS: A multinational (United States, Japan, France, Germany, Italy, Spain, and United Kingdom) study of patients diagnosed with stage I to III HR+/HER2- breast cancer, either receiving adjuvant treatment or under postadjuvant surveillance, was conducted between June and October 2019. Patients were identified by their consulting physician and invited to complete the Functional Assessment of Cancer Therapy-Breast (FACT-B) and the EQ-5D-5L pen and paper questionnaires. EQ-5D-5L index scores were derived by using available country-specific health state value sets, where available, and numerically compared with general population scores derived from published normative and population data. Descriptive summary statistics were reported for FACT-B, Functional Assessment of Cancer Therapy-General (FACT-G) (total and specific subscales), the EQ-5D index scores, and the EQ-VAS scores for each country. Results were stratified according to disease-free treatment status (active adjuvant treatment or postadjuvant surveillance), age (25-44, 45-54, 55-64, or ≥65 years), stage (I, II, or III), and menopausal status at the time of questionnaire completion (pre-/peri-menopausal or postmenopausal). FINDINGS: Overall, 1110 patients completed the HRQOL questionnaires (mean age, 59 years; 79% active adjuvant treatment, and 21% under surveillance postadjuvant treatment at time of questionnaire administration; 31% stage I, 48% stage II, and 20% stage III at diagnosis). Of these, 1102 completed the FACT-B and 1083 completed the EQ-5D-5L questionnaires. The mean (SD) FACT-B total score was 99.0 (21.9). The mean FACT-G total score was 72.5 (17.8), which was comparable to the published normative score. The mean EQ-5D index and EQ-VAS scores for each country were similar to corresponding population means; EQ-5D index scores ranged from 0.842 (0.098) in Japan to 0.916 (0.109) in France, and EQ-VAS scores from 68.0 (18.4) in Germany to 78.6 (16.4) in the United States. In addition, mean scores were comparable between the active adjuvant treatment and postadjuvant surveillance groups for the FACT-B total (99.4 [22.5] and 97.7 [19.7], respectively), FACT-G total (72.8 [18.3] and 71.3 [16.0]), EQ-5D index score (0.868 [0.135] and 0.869 [0.142]), and EQ-VAS (74.9 [17.2] and 74.4 [16.1]). IMPLICATIONS: Patient-reported HRQOL among patients with HR+/HER2- early breast cancer who were disease-free was high, with reported scores comparable to normative scores. These results improve our understanding of HRQOL among patients with early disease and may facilitate future studies examining the potential impact of adjuvant treatment and disease recurrence, including metastasis.

Roles of ATM and ATR in DNA double strand breaks and replication stress.

The maintenance of genome integrity is critical for the faithful replication of the genome during cell division and for protecting cells from accumulation of DNA damage, which if left unrepaired leads to a loss of genetic information, a breakdown in cell function and ultimately cell death and cancer. ATM and ATR are master kinases that are integral to homologous recombination-mediated repair of double strand breaks and preventing accumulation of dangerous DNA structures and genome instability during replication stress. While the roles of ATM and ATR are heavily intertwined in response to double strand breaks, their roles diverge in the response to replication stress. This review summarises our understanding of the players and their mode of actions in recruitment, activation and activity of ATM and ATR in response to DNA damage and replication stress and discusses how controlling localisation of these kinases and their activators allows them to orchestrate a stress-specific response.

Roles of ATM and ATR in DNA double strand breaks and replication stress.

The maintenance of genome integrity is critical for the faithful replication of the genome during cell division and for protecting cells from accumulation of DNA damage, which if left unrepaired leads to a loss of genetic information, a breakdown in cell function and ultimately cell death and cancer. ATM and ATR are master kinases that are integral to homologous recombination-mediated repair of double strand breaks and preventing accumulation of dangerous DNA structures and genome instability during replication stress. While the roles of ATM and ATR are heavily intertwined in response to double strand breaks, their roles diverge in the response to replication stress. This review summarises our understanding of the players and their mode of actions in recruitment, activation and activity of ATM and ATR in response to DNA damage and replication stress and discusses how controlling localisation of these kinases and their activators allows them to orchestrate a stress-specific response.

Systemic capillary leak syndrome: a rare but potentially life-threatening cause of protein loss and oedema in B cell prolymphocytic leukaemia.

A 64-year-old man had a several year history of B prolymphocytic leukaemia (PLL) which behaved indolently and had not required any treatment. Five years after diagnosis, he developed hypoalbuminaemia associated with severe lower-limb oedema, consistent with systemic capillary leak syndrome (SCLS). He recovered spontaneously but went on to have three further increasingly severe and protracted episodes over the subsequent 18 months. There was no identifiable precipitating factor for these episodes, but his peripheral lymphocyte count continued to increase slowly. The start of treatment for his PLL with chemoimmunotherapy was followed by a rapid resolution of residual oedema and normalisation of serum albumin. He has had no further attacks of SCLS in the 14 months since he started therapy for PLL. SCLS is a rare consequence of haematological malignancy which may show an excellent response to treatment of the haematological disease.

Structures and regulations of ATM and ATR, master kinases in genome integrity.

Homologous recombination (HR) is a faithful repair mechanism for double stranded DNA breaks. Two highly homologous master kinases, the tumour suppressors ATM and ATR (Tel1 and Mec1 in yeast), coordinate cell cycle progression with repair during HR. Despite their importance, our molecular understanding of these apical coordinators has been limited, in part due to their large sizes. With the recent development in cryo-electron microscopy, significant advances have been made in structural characterisation of these proteins in the last two years. These structures, combined with new biochemical studies, now provide a more detailed understanding of how a low basal activity is maintained and how activation may occur. In this review, we summarize recent advances in the structural and molecular understanding of these key components in HR, compare the common and distinct features of these kinases and suggest aspects of structural components that are likely to be involved in regulating its activity.

Cryo-EM Structure of Nucleotide-Bound Tel1ATM Unravels the Molecular Basis of Inhibition and Structural Rationale for Disease-Associated Mutations.

Yeast Tel1 and its highly conserved human ortholog ataxia-telangiectasia mutated (ATM) are large protein kinases central to the maintenance of genome integrity. Mutations in ATM are found in ataxia-telangiectasia (A-T) patients and ATM is one of the most frequently mutated genes in many cancers. Using cryoelectron microscopy, we present the structure of Tel1 in a nucleotide-bound state. Our structure reveals molecular details of key residues surrounding the nucleotide binding site and provides a structural and molecular basis for its intrinsically low basal activity. We show that the catalytic residues are in a productive conformation for catalysis, but the phosphatidylinositol 3-kinase-related kinase (PIKK) regulatory domain insert restricts peptide substrate access and the N-lobe is in an open conformation, thus explaining the requirement for Tel1 activation. Structural comparisons with other PIKKs suggest a conserved and common allosteric activation mechanism. Our work also provides a structural rationale for many mutations found in A-T and cancer.

Widespread bacterial lysine degradation proceeding via glutarate and L-2-hydroxyglutarate.

Lysine degradation has remained elusive in many organisms including Escherichia coli. Here we report catabolism of lysine to succinate in E. coli involving glutarate and L-2-hydroxyglutarate as intermediates. We show that CsiD acts as an α-ketoglutarate-dependent dioxygenase catalysing hydroxylation of glutarate to L-2-hydroxyglutarate. CsiD is found widespread in bacteria. We present crystal structures of CsiD in complex with glutarate, succinate, and the inhibitor N-oxalyl-glycine, demonstrating strong discrimination between the structurally related ligands. We show that L-2-hydroxyglutarate is converted to α-ketoglutarate by LhgO acting as a membrane-bound, ubiquinone-linked dehydrogenase. Lysine enters the pathway via 5-aminovalerate by the promiscuous enzymes GabT and GabD. We demonstrate that repression of the pathway by CsiR is relieved upon glutarate binding. In conclusion, lysine degradation provides an important link in central metabolism. Our results imply the gut microbiome as a potential source of glutarate and L-2-hydroxyglutarate associated with human diseases such as cancer and organic acidurias.

The Wnt5a Receptor, Receptor Tyrosine Kinase-Like Orphan Receptor 2, Is a Predictive Cell Surface Marker of Human Mesenchymal Stem Cells with an Enhanced Capacity for Chondrogenic Differentiation.

Multipotent mesenchymal stem cells (MSCs) have enormous potential in tissue engineering and regenerative medicine. However, until now, their development for clinical use has been severely limited as they are a mixed population of cells with varying capacities for lineage differentiation and tissue formation. Here, we identify receptor tyrosine kinase-like orphan receptor 2 (ROR2) as a cell surface marker expressed by those MSCs with an enhanced capacity for cartilage formation. We generated clonal human MSC populations with varying capacities for chondrogenesis. ROR2 was identified through screening for upregulated genes in the most chondrogenic clones. When isolated from uncloned populations, ROR2+ve MSCs were significantly more chondrogenic than either ROR2-ve or unfractionated MSCs. In a sheep cartilage-repair model, they produced significantly more defect filling with no loss of cartilage quality compared with controls. ROR2+ve MSCs/perivascular cells were present in developing human cartilage, adult bone marrow, and adipose tissue. Their frequency in bone marrow was significantly lower in patients with osteoarthritis (OA) than in controls. However, after isolation of these cells and their initial expansion in vitro, there was greater ROR2 expression in the population derived from OA patients compared with controls. Furthermore, osteoarthritis-derived MSCs were better able to form cartilage than MSCs from control patients in a tissue engineering assay. We conclude that MSCs expressing high levels of ROR2 provide a defined population capable of predictably enhanced cartilage production. Stem Cells 2017;35:2280-2291.

Twitchin kinase inhibits muscle activity.

Muscle sarcomeres contain giant polypeptides composed of multiple immunoglobulin and fibronectin domains and one or two protein kinase domains. Although binding partners for a number of this family's kinase domains have been identified, the catalytic necessity of these kinase domains remains unknown. In addition, various members of this kinase family are suspected pseudokinases with no or little activity. Here we address catalytic necessity for the first time, using the prototypic invertebrate representative twitchin (UNC-22) from Caenorhabditis elegans In in vitro experiments, change of a conserved lysine (K) that is involved in ATP coordination to alanine (A) resulted in elimination of kinase activity without affecting the overall structure of the kinase domain. The same mutation, unc-22(sf21), was generated in the endogenous twitchin gene. The unc-22(sf21) worms have well-organized sarcomeres. However, unc-22(sf21) mutants move faster than wild-type worms and, by optogenetic experiments, contract more. Wild-type nematodes exhibited greater competitive fitness than unc-22(sf21) mutants. Thus the catalytic activity of twitchin kinase has a role in vivo, where it inhibits muscle activity and is likely maintained by selection.

Endobronchial valves in the management of bronchial fistulae caused by bronchopulmonary aspergillosis.

Following an aggressive episode of bronchopulmonary aspergillosis, a 54-year-old man developed a symptomatic air leak via a tunnel between the left upper lobe and an extra chest wall cavity. Following the failure of several surgical procedures to close the tunnel, endobronchial valves normally used in management of emphysema were used to successfully treat the air leak.

Graduate entry medicine: selection criteria and student performance.

BACKGROUND: Graduate entry medicine raises new questions about the suitability of students with different backgrounds. We examine this, and the broader issue of effectiveness of selection and assessment procedures. METHODS: The data included background characteristics, academic record, interview score and performance in pre-clinical modular assessment for two years intake of graduate entry medical students. Exploratory factor analysis is a powerful method for reducing a large number of measures to a smaller group of underlying factors. It was used here to identify patterns within and between the selection and performance data. PRINCIPAL FINDINGS: Basic background characteristics were of little importance in predicting exam success. However, easily interpreted components were detected within variables comprising the 'selection' and 'assessment' criteria. Three selection components were identified ('Academic', 'GAMSAT', 'Interview') and four assessment components ('General Exam', 'Oncology', 'OSCE', 'Family Case Study'). There was a striking lack of relationships between most selection and performance factors. Only 'General Exam' and 'Academic' showed a correlation (Pearson's r = 0.55, p<0.001). CONCLUSIONS: This study raises questions about methods of student selection and their effectiveness in predicting performance and assessing suitability for a medical career. Admissions tests and most exams only confirmed previous academic achievement, while interview scores were not correlated with any consequent assessment.

Locked intramedullary fixation vs plating for displaced and shortened mid-shaft clavicle fractures: a randomized clinical trial.

BACKGROUND: Recent literature supports surgical intervention for shortened, displaced, mid-shaft clavicle fractures. We present the results of a randomized clinical trial comparing locked intramedullary fixation and plate fixation for short, displaced, mid-shaft clavicle fractures. MATERIALS AND METHODS: Local ethical approval was obtained and power analysis and sample size calculations were performed prior to commencement. Patients randomized to 2 groups to be treated with either locked intramedullary fixation or plating. Patients regularly followed up to clinical and radiographic union. The primary outcome measure was the Constant score, secondary outcome measures included the Oxford shoulder score, union rate, and complication rates. RESULTS: Seventeen patients were randomized to locked intramedullary fixation and 15 randomized to plating. Mean age was 29.3 years. Mean follow-up was 12.4 months. There was no significant difference in either Constant scores (P = .365) or Oxford scores (P = .773). There was 100% union in both groups. In the intramedullary group, 1 case of soft tissue irritation settled after the pin removal; 1 pin backed out and was revised. Three superficial wound infections resulted in plate removal and 8 plates (53%) were removed. DISCUSSION: Intramedullary fixation has the theoretical advantage of preserving the periosteal blood supply, but carries the morbidity of pin removal. Clavicle plates are not routinely removed but require greater exposure and may compromise periosteal blood supply. CONCLUSION: Both locked intramedullary fixation and plating produce good functional results; however, metalwork may need to be removed as a second procedure.

Population based absolute and relative survival to 1 year of people with diabetes following a myocardial infarction: a cohort study using hospital admissions data.

BACKGROUND: People with diabetes who experience an acute myocardial infarction (AMI) have a higher risk of death and recurrence of AMI. This study was commissioned by the Department for Transport to develop survival tables for people with diabetes following an AMI in order to inform vehicle licensing. METHODS: A cohort study using data obtained from national hospital admission datasets for England and Wales was carried out selecting all patients attending hospital with an MI for 2003-2006 (inclusion criteria: aged 30+ years, hospital admission for MI (defined using ICD 10 code I21-I22). STATA was used to create survival tables and factors associated with survival were examined using Cox regression. RESULTS: Of 157,142 people with an MI in England and Wales between 2003-2006, the relative risk of death or recurrence of MI for those with diabetes (n = 30,407) in the first 90 days was 1.3 (95%CI: 1.26-1.33) crude rates and 1.16 (95%CI: 1.1-1.2) when controlling for age, gender, heart failure and surgery for MI) compared with those without diabetes (n = 129,960). At 91-365 days post AMI the risk was 1.7 (95% CI 1.6-1.8) crude and 1.50 (95%CI: 1.4-1.6) adjusted. The relative risk of death or re-infarction was higher at younger ages for those with diabetes and directly after the AMI (Relative risk; RR: 62.1 for those with diabetes and 28.2 for those without diabetes aged 40-49 [compared with population risk]). CONCLUSIONS: This is the first study to provide population based tables of age stratified risk of re-infarction or death for people with diabetes compared with those without diabetes. These tables can be used for giving advice to patients, developing a baseline to compare intervention studies or developing license or health insurance guidelines.

The Kathmandu Declaration: "Life Circle" approach to prevention and care of diabetes mellitus.

OBJECTIVES: To formulate strategies and action plans for the prevention and care of diabetes mellitus as part of the implementation of the International Diabetes Federation (IDF) United Nations Resolution (UNR) 61/225 through a unique concept of a "Life Circle" approach. METHOD: Consensus following review of evidence available and presented at a meeting convened to achieve the objective co-chaired by the IDF President and President elect and diabetologists from several countries in the IDF regions. CONCLUSIONS: The Kathmandu Declaration presents the concept of a "Life Circle" approach to prevention and care of diabetes--a continuum beginning from preconception, pregnancy, infancy and childhood to adult life in an integrated manner. Emphasis is on the benefits on entering the circle at any point and formulates guidelines that could be incorporated in any national diabetes prevention and care programme, indicating the interactive role of all known aetiological factors.

Risk factors for childhood obesity at age 5: analysis of the millennium cohort study.

BACKGROUND: Weight at age 5 is a predictor for future health of the individual. This study examines risk factors for childhood obesity with a focus on ethnicity. METHODS: Data from the Millennium Cohort study were used. 17,561 singleton children of White/European (n = 15,062), Asian (n = 1,845) or African (n = 654) background were selected. Logistic regression and likelihood ratio tests were used to examine factors associated with obesity at age 5. All participants were interviewed in their own homes. The main exposures examined included; Birth weight, sedentary lifestyle, family health behaviours, ethnicity, education and income. RESULTS: Children with a sedentary lifestyle, large at birth, with high risk family health behaviours (overweight mothers, smoking near the child, missing breakfast) and from a family with low income or low educational attainment, were more likely to be obese regardless of ethnicity. Feeding solid food before 3 months was associated with obesity in higher income White/European families. Even when controlling for socioeconomic status, ethnic background is an important independent risk factor for childhood obesity [Odds ratio of obesity; was 1.7 (95%CI: 1.2-2.3) for Asian and 2.7 (95%CI: 1.9-3.9) for African children, compared to White/European]. The final adjusted model suggests that increasing income does not have a great impact on lowering obesity levels, but that higher academic qualifications are associated with lower obesity levels [Odds of obesity: 0.63 (95%CI: 0.52-0.77) if primary carer leaves school after age 16 compared at age 16]. CONCLUSIONS: Education of the primary carer is an important modifiable factor which can be targeted to address rising obesity levels in children. Interventions should be family centred supporting and showing people how they can implement lifestyle changes in their family.