Proton transfer from glutamate 286 determines the transition rates between oxygen intermediates in cytochrome c oxidase

AbstractWe have investigated the electron–proton coupling during the peroxy (PR) to oxo-ferryl (F) and F to oxidised (O) transitions in cytochrome c oxidase from Rhodobacter sphaeroides. The kinetics of these reactions were investigated in two different mutant enzymes: (1) ED(I-286), in which one of the key residues in the D-pathway, E(I-286), was replaced by an aspartate which has a shorter side chain than that of the glutamate and, (2) ML(II-263), in which the redox potential of CuA is increased by ∼100 mV, which slows electron transfer to the binuclear centre during the F→O transition by a factor of ∼200. In ED(I-286) proton uptake during PR→F was slowed by a factor of ∼5, which indicates that E(I-286) is the proton donor to PR. In addition, in the mutant enzyme the F→O transition rate displayed a deuterium isotope effect of ∼2.5 as compared with ∼7 in the wild-type enzyme. Since the entire deuterium isotope effect was shown to be associated with a single proton-transfer reaction in which the proton donor and acceptor must approach each other (M. Karpefors, P. Ådelroth, P. Brzezinski, Biochemistry 39 (2000) 6850), the smaller deuterium isotope effect in ED(I-286) indicates that proton transfer from E(I-286) determines the rate also of the F→O transition. In ML(II-263) the electron-transfer to the binuclear centre is slower than the intrinsic proton-transfer rate through the D-pathway. Nevertheless, both electron and proton transfer to the binuclear centre displayed a deuterium isotope effect of ∼8, i.e., about the same as in the wild-type enzyme, which shows that these reactions are intimately coupled

Regulation of Spo12 Phosphorylation and Its Essential Role in the FEAR Network

Background: In budding yeast, the protein phosphatase Cdc14 coordinates late mitotic events and triggers exit from mitosis. During early anaphase, Cdc14 is activated by the FEAR network, but how signaling through the FEAR network occurs is poorly understood. Results: We find that the FEAR network component Spo12 is phosphorylated on S118. This phosphorylation is essential for Spo12 function and is restricted to early anaphase, when the FEAR network is active. The anaphase-specific phosphorylation of Spo12 requires mitotic CDKs and depends on the FEAR network components Separase and Slk19. Furthermore, we find that CDC14 is required to maintain Spo12 in the dephosphorylated state prior to anaphase. Conclusions: Our results show that anaphase-specific phosphorylation of Spo12 is essential for FEAR network function and raise the interesting possibility that Cdc14 itself helps to prevent the FEAR network from being prematurely activated.National Institutes of Health (U.S.) (grant GM 056800)Howard Hughes Medical Institute (Investigator

New primary renal diagnosis codes for the ERA-EDTA

The European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry has produced a new set of primary renal diagnosis (PRD) codes that are intended for use by affiliated registries. It is designed specifically for use in renal centres and registries but is aligned with international coding standards supported by the WHO (International Classification of Diseases) and the International Health Terminology Standards Development Organization (SNOMED Clinical Terms). It is available as supplementary material to this paper and free on the internet for non-commercial, clinical, quality improvement and research use, and by agreement with the ERA-EDTA Registry for use by commercial organizations. Conversion between the old and the new PRD codes is possible. The new codes are very flexible and will be actively managed to keep them up-to-date and to ensure that renal medicine can remain at the forefront of the electronic revolution in medicine, epidemiology research and the use of decision support systems to improve the care of patients

Global survey of guidelines for the management of epilepsy in pregnancy: A report from the international league against epilepsy task force on women and pregnancy

The ILAE Task Force on Women and Pregnancy conducted a survey among ILAE Chapters of their use of guidelines or recommendations for the management of women with epilepsy during pregnancy. A web-based questionnaire including 10 questions was sent to the 118 ILAE Chapters in December 2017 with repeated reminders until the end of February 2018. In total, 77 chapters (65%) responded, although not to all questions. Out of those responding, 68% reported having guidelines or recommendations, 34% of which were from 2014 or earlier. At least 20% of the guidelines did not include information on possible risk to cognitive development, information regarding specific risks with specific antiepileptic drugs, nor recommendations regarding selection of antiepileptic drugs. Among those responding to the question, 91% reported that recommendations were made regarding folate supplementation, but the recommended dose ranged from 0.4 mg/d to 4 mg/d or more; 34% did not include recommendations regarding drug level monitoring during pregnancy, and 19% did not include guidelines on breastfeeding. Our survey demonstrates that there is a need for the development of up-to-date, globally applicable recommendations for the management of epilepsy during pregnancy.Fil: Tomson, Torbjörn. Karolinska Huddinge Hospital. Karolinska Institutet; Suecia. Karolinska University Hospital. Department of Neurology; SueciaFil: Battino, Dina. Fondazione IRCCS Istituto Neurologico Carlo Besta. Department of Neurophysiology and Experimental Epileptology. Epilepsy Center; ItaliaFil: Bromley, Rebecca. Central Manchester University Hospitals NHS Foundation Trust; Reino Unido. University of Manchester; Reino UnidoFil: Kochen, Sara Silvia. Universidad Nacional Arturo Jauretche. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Provincia de Buenos Aires. Ministerio de Salud. Hospital Alta Complejidad en Red El Cruce Dr. Néstor Carlos Kirchner Samic. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Unidad Ejecutora de Estudios en Neurociencias y Sistemas Complejos; ArgentinaFil: Meador, Kimford J.. University of Stanford; Estados UnidosFil: Pennell, Page B.. Brigham and Women's Hospital. Harvard Medical School. Department of Neurology. Divisions of Epilepsy and Women's Health; Estados UnidosFil: Thomas, Sanjeev V.. Sree Chitra Tirunal Institute of Medical Sciences and Technology. Department of Neurology; Indi

Sudden Unexpected Death in Epilepsy: A PersonaliZed Prediction Tool

OBJECTIVE: To develop and validate a tool for individualised prediction of Sudden Unexpected Death in Epilepsy (SUDEP) risk, we re-analysed data from one cohort and three case-control studies undertaken 1980-2005. METHODS: We entered 1273 epilepsy cases (287 SUDEP, 986 controls) and 22 clinical predictor variables into a Bayesian logistic regression model. RESULTS: Cross-validated individualized model predictions were superior to baseline models developed from only average population risk or from generalised tonic-clonic seizure frequency (pairwise difference in leave-one-subject-out expected log posterior density = 35.9, SEM +/-12.5, and 22.9, SEM +/-11.0 respectively). The mean cross-validated (95% Credibility Interval) Area Under the Receiver Operating Curve was 0.71 (0.68 to 0.74) for our model versus 0.38 (0.33 to 0.42) and 0.63 (0.59 to 0.67) for the baseline average and generalised tonic-clonic seizure frequency models respectively. Model performance was weaker when applied to non-represented populations. Prognostic factors included generalized tonic-clonic and focal-onset seizure frequency, alcohol excess, younger age of epilepsy onset and family history of epilepsy. Anti-seizure medication adherence was associated with lower risk. CONCLUSIONS: Even when generalised to unseen data, model predictions are more accurate than population-based estimates of SUDEP. Our tool can enable risk-based stratification for biomarker discovery and interventional trials. With further validation in unrepresented populations it may be suitable for routine individualized clinical decision-making. Clinicians should consider assessment of multiple risk factors, and not only focus on the frequency of convulsions

The accuracy of diagnostic coding for acute kidney injury in England - a single centre study.

BACKGROUND: Acute kidney injury (AKI) is an independent risk factor for mortality and is responsible for a significant burden of healthcare expenditure, so accurate measurement of its incidence is important. Administrative coding data has been used for assessing AKI incidence, and shows an increasing proportion of hospital bed days attributable to AKI. However, the accuracy of coding for AKI and changes in coding over time have not been studied in England. METHODS: We studied a random sample of admissions from 2005 and 2010 where ICD-10 code N17 (acute renal failure) was recorded in the administrative coding data at one acute NHS Foundation Trust in England. Using the medical notes and computerised records we examined the demographic and clinical details of these admissions. RESULTS: Against a 6.3% (95% CI 4.8-7.9%) increase in all non-elective admissions, we found a 64% increase in acute renal failure admissions (95% CI 41%-92%, p < 0.001) in 2010 compared to 2005. Median age was 78 years (IQR 72-87), 11-25% had a relevant pre-admission co-morbidity and 64% (55-73%) were taking drugs known to be associated with AKI. Over both years, 95% (91-99%) of cases examined met the Kidney Disease: Improving Global Outcomes criteria for AKI. CONCLUSIONS: Patients with hospital admissions where AKI has been coded are elderly with multiple co-morbidities. Our results demonstrate a high positive predictive value of coding data for a clinical diagnosis of AKI, with no suggestion of marked changes in coding of AKI between 2005 and 2010.RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are

Ensuring HLA-matched platelet support requires an ethnic diverse donor population

BACKGROUND: Patients refractory for platelet transfusions benefit from human leukocyte antigen (HLA)-matched platelet transfusions. Differences in ethnic background of patients and donors could hamper the availability of sufficient numbers of HLA-matched donors for all patients. We evaluated our HLA-matched donor program and explored the role of ethnic background of patients related to the number of available donors. METHODS: We performed a cohort study among consecutive patients who received HLA-matched platelet concentrates in the Netherlands between 1994 and 2017. The number of available matched donors was determined per patient. Haplotypes were constructed from genotypes with computer software (PyPop). Based on haplotypes, HaploStats, an algorithm from the National Marrow Donor Program, was used to assess the most likely ethnic background for patients with 5 or fewer and 30 or more donors. RESULTS: HLA typing was available for 19,478 donors in September 2017. A total of 1206 patients received 12,350 HLA-matched transfusions. A median of 83 (interquartile range, 18-266) donors were available per patient. For 95 (10.3%) patients, 5 or fewer donors were available. These patients were more likely to have an African American background, whereas patients with 30 or more donors were more often from Caucasian origin, compared with Caucasian origin for patients with 30 donors. CONCLUSION: Adequate transfusion support could be guaranteed for most but not all refractory patients. More non-Caucasian donors are required to ensure the availability of HLA-matched donors for all patients in the Netherlands

Effect of a reduction in glomerular filtration rate after nephrectomy on arterial stiffness and central hemodynamics: rationale and design of the EARNEST study

Background: There is strong evidence of an association between chronic kidney disease (CKD) and cardiovascular disease. To date, however, proof that a reduction in glomerular filtration rate (GFR) is a causative factor in cardiovascular disease is lacking. Kidney donors comprise a highly screened population without risk factors such as diabetes and inflammation, which invariably confound the association between CKD and cardiovascular disease. There is strong evidence that increased arterial stiffness and left ventricular hypertrophy and fibrosis, rather than atherosclerotic disease, mediate the adverse cardiovascular effects of CKD. The expanding practice of live kidney donation provides a unique opportunity to study the cardiovascular effects of an isolated reduction in GFR in a prospective fashion. At the same time, the proposed study will address ongoing safety concerns that persist because most longitudinal outcome studies have been undertaken at single centers and compared donor cohorts with an inappropriately selected control group.&lt;p&gt;&lt;/p&gt; Hypotheses: The reduction in GFR accompanying uninephrectomy causes (1) a pressure-independent increase in aortic stiffness (aortic pulse wave velocity) and (2) an increase in peripheral and central blood pressure.&lt;p&gt;&lt;/p&gt; Methods: This is a prospective, multicenter, longitudinal, parallel group study of 440 living kidney donors and 440 healthy controls. All controls will be eligible for living kidney donation using current UK transplant criteria. Investigations will be performed at baseline and repeated at 12 months in the first instance. These include measurement of arterial stiffness using applanation tonometry to determine pulse wave velocity and pulse wave analysis, office blood pressure, 24-hour ambulatory blood pressure monitoring, and a series of biomarkers for cardiovascular and bone mineral disease.&lt;p&gt;&lt;/p&gt; Conclusions: These data will prove valuable by characterizing the direction of causality between cardiovascular and renal disease. This should help inform whether targeting reduced GFR alongside more traditional cardiovascular risk factors is warranted. In addition, this study will contribute important safety data on living kidney donors by providing a longitudinal assessment of well-validated surrogate markers of cardiovascular disease, namely, blood pressure and arterial stiffness. If any adverse effects are detected, these may be potentially reversed with the early introduction of targeted therapy. This should ensure that kidney donors do not come to long-term harm and thereby preserve the ongoing expansion of the living donor transplant program.&lt;p&gt;&lt;/p&gt

"Practical Knowledge" and Perceptions of Antibiotics and Antibiotic Resistance Among Drugsellers in Tanzanian Private Drugstores.

Studies indicate that antibiotics are sold against regulation and without prescription in private drugstores in rural Tanzania. The objective of the study was to explore and describe antibiotics sale and dispensing practices and link it to drugseller knowledge and perceptions of antibiotics and antibiotic resistance. Exit customers of private drugstores in eight districts were interviewed about the drugstore encounter and drugs bought. Drugsellers filled in a questionnaire with closed- and open-ended questions about antibiotics and resistance. Data were analyzed using mixed quantitative and qualitative methods. Of 350 interviewed exit customers, 24% had bought antibiotics. Thirty percent had seen a health worker before coming and almost all of these had a prescription. Antibiotics were dispensed mainly for cough, stomachache, genital complaints and diarrhea but not for malaria or headache. Dispensed drugs were assessed as relevant for the symptoms or disease presented in 83% of all cases and 51% for antibiotics specifically. Non-prescribed drugs were assessed as more relevant than the prescribed. The knowledge level of the drugseller was ranked as high or very high by 75% of the respondents. Seventy-five drugsellers from three districts participated. Seventy-nine percent stated that diseases caused by bacteria can be treated with antibiotics but 24% of these also said that antibiotics can be used for treating viral disease. Most (85%) said that STI can be treated with antibiotics while 1% said the same about headache, 4% general weakness and 3% 'all diseases'. Seventy-two percent had heard of antibiotic resistance. When describing what an antibiotic is, the respondents used six different kinds of keywords. Descriptions of what antibiotic resistance is and how it occurs were quite rational from a biomedical point of view with some exceptions. They gave rise to five categories and one theme: Perceiving antibiotic resistance based on practical experience. The drugsellers have considerable "practical knowledge" of antibiotics and a perception of antibiotic resistance based on practical experience. In the process of upgrading private drugstores and formalizing the sale of antibiotics from these outlets in resource-constrained settings, their "practical knowledge" as well as their perceptions must be taken into account in order to attain rational dispensing practices

Understanding cost of care for patients on renal replacement therapy: looking beyond fixed tariffs.

BACKGROUND: In a number of countries, reimbursement to hospitals providing renal dialysis services is set according to a fixed tariff. While the cost of maintenance dialysis and transplant surgery are amenable to a system of fixed tariffs, patients with established renal failure commonly present with comorbid conditions that can lead to variations in the need for hospitalization beyond the provision of renal replacement therapy. METHODS: Patient-level cost data for incident renal replacement therapy patients in England were obtained as a result of linkage of the Hospital Episodes Statistics dataset to UK Renal Registry data. Regression models were developed to explore variations in hospital costs in relation to treatment modality, number of years on treatment and factors such as age and comorbidities. The final models were then used to predict annual costs for patients with different sets of characteristics. RESULTS: Excluding the cost of renal replacement therapy itself, inpatient costs generally decreased with number of years on treatment for haemodialysis and transplant patients, whereas costs for patients receiving peritoneal dialysis remained constant. Diabetes was associated with higher mean annual costs for all patients irrespective of treatment modality and hospital setting. Age did not have a consistent effect on costs. CONCLUSIONS: Combining predicted hospital costs with the fixed costs of renal replacement therapy showed that the total cost differential for a patient continuing on dialysis rather than receiving a transplant is considerable following the first year of renal replacement therapy, thus reinforcing the longer-term economic advantage of transplantation over dialysis for the health service.<br/