Background
Most recently described human platelet antigens (HPAs) have been detected in cases of fetomaternal alloimmune thrombocytopenia (FMAIT) where the mother has been immunized against a ...low‐frequency antigen that the fetus has inherited from the father. Low‐frequency antigens are not represented in normal panel platelets (PLTs) and antibody detection and identification in such cases requires incubation of maternal serum with paternal PLTs and definition of the causative mutation.
Study Design and Methods
A suspected case of FMAIT was investigated for PLT‐specific antibodies using a panel of both HPA‐typed and paternal PLTs. HPA typing was performed by polymerase chain reaction with sequence‐specific primers and further DNA analysis was performed using direct sequencing of the coding regions of the ITGA2B and ITGB3 genes.
Results
Maternal antibodies reactive only with paternal PLTs were localized to glycoprotein (GP)IIb/IIIa using the monoclonal antibody immobilization of PLT antibody assay. A single‐nucleotide polymorphism was detected in Exon 23 of ITGA2B in the father and affected child, which predicted a V740L substitution in the mature protein. Recombinant V740L mutated GPIIb expressed in HEK293 cells was specifically recognized by maternal antibodies. The polymorphism was not detected either in the mother or in a cohort of 100 donors.
Conclusion
The V740L polymorphism defines a new low‐frequency antigen implicated in two cases of FMAIT in a single family. Low‐frequency HPAs are clinically important and their elucidation requires both crossmatch studies and gene sequencing in cases where there is strong clinical evidence of FMAIT but initial laboratory investigations do not support the diagnosis.
Micro-RNA, small noncoding RNA fragments involved in gene regulation, and microvesicles, membrane-bound particles less than 1 μm known to regulate cellular processes including responses to injury, ...may serve as disease-specific biomarkers of acute kidney injury. We evaluated the feasibility of measuring these signals as well as other known acute kidney injury biomarkers in a mixed pediatric cardiac surgery population.
Single center prospective cohort feasibility study.
PICU.
Twenty-four children (≤ 17 yr) undergoing cardiac surgery with cardiopulmonary bypass without preexisting inflammatory state, acute kidney injury, or extracorporeal life support.
None.
Acute kidney injury was defined according to modified Kidney Diseases Improving Global Outcomes criteria. Blood and urine samples were collected preoperatively and at 6-12 and 24 hours. Microvesicles derivation was assessed using flow cytometry and NanoSight analysis. Micro-RNAs were isolated from plasma and analyzed by microarray and quantitative real-time polymerase chain reaction. Data completeness for the primary outcomes was 100%. Patients with acute kidney injury (n = 14/24) were younger, underwent longer cardiopulmonary bypass, and required greater inotrope support. Acute kidney injury subjects had different fractional content of platelets and endothelial-derived microvesicles before surgery. Platelets and endothelial microvesicles levels were higher in acute kidney injury patients. A number of micro-RNA species were differentially expressed in acute kidney injury patients. Pathway analysis of candidate target genes in the kidney suggested that the most often affected pathways were phosphatase and tensin homolog and signal transducer and activator of transcription 3 signaling.
Microvesicles and micro-RNAs expression patterns in pediatric cardiac surgery patients can be measured in children and potentially serve as tools for stratification of patients at risk of acute kidney injury.
Extracorporeal membrane oxygenation is a treatment for Persistent Pulmonary Hypertension of the Newborn with high mortality.
the extracorporeal membrane oxygenation circuit results in inflammatory ...responses that mitigate against successful weaning.
Single-center prospective observational feasibility study.
PICU.
Twenty-four neonates requiring extracorporeal membrane oxygenation support for Persistent Pulmonary Hypertension of the Newborn.
None.
The reference outcome was death or more than 7 days of extracorporeal membrane oxygenation support. Other outcomes included serial measures of plasma-free hemoglobin and markers of its metabolism, leucocyte, platelet and endothelial activation, and biomarkers of inflammation. Of 24 participants recruited between February 2016 and June 2017, 10 died or required prolonged extracorporeal membrane oxygenation support. These patients were sicker at baseline with higher levels of plasma-free hemoglobin within 12 hours of cannulation (geometric mean ratio, 1.92; 95% CIs, 1.00-3.67; p = 0.050) but not thereafter, versus those requiring less than 7 days extracorporeal membrane oxygenation. Serum haptoglobin concentrations were significantly elevated in both groups. Patients who died or required prolonged extracorporeal membrane oxygenation support demonstrated elevated levels of platelet-leucocyte aggregation, but decreased concentrations of mediators of the inflammatory response: interleukin-8, C-reactive protein, and tumor necrosis factor α.
Clinical status at baseline and not levels of plasma-free hemoglobin or the systemic inflammatory response may determine the requirement for prolonged extracorporeal membrane oxygenation support in neonates.
Microtubules and their associated proteins (MAPs) underpin the polarity of specialised cells. Adenomatous polyposis coli (APC) is one such MAP with a multifunctional agenda that requires precise ...intracellular localisations. Although APC has been found to associate with kinesin-2 subfamily members, the exact mechanism for the peripheral localization of APC remains unclear. Here we show that the heavy chain of kinesin-1 directly interacts with the APC C-terminus, contributing to the peripheral localisation of APC in fibroblasts. In rat hippocampal neurons the kinesin-1 binding domain of APC is required for its axon tip enrichment. Moreover, we demonstrate that APC requires interactions with both kinesin-2 and kinesin-1 for this localisation. Underlining the importance of the kinesin-1 association, neurons expressing APC lacking kinesin-1-binding domain have shorter axons. The identification of this novel kinesin-1-APC interaction highlights the complexity and significance of APC localisation in neurons.
This is a protocol for a Cochrane Review (intervention). The objectives are as follows:
Primary objective:
To identify and summarise the findings of RCTs evaluating interventions that target the ...inflammatory response to cardiac surgery and measure both markers of inflammation and clinical outcomes.
Secondary objective:
To evaluate whether interventions that target different drivers of inflammation during cardiac surgery influence the nature of the inflammatory response or clinical outcomes.
It is unclear whether the innate immune response represents a therapeutic target for organ protection strategies in cardiac surgery.
A systematic review of trials of interventions targeting the ...inflammatory response to cardiac surgery reporting treatment effects on both innate immune system cytokines and organ injury was performed. The protocol was registered at the International Prospective Register of Systematic Reviews: CRD42020187239. Searches of the Cochrane Central Register of Controlled Trials, MEDLINE, and Embase were performed. Random-effects meta-analyses were used for the primary analysis. A separate analysis of individual patient data from six studies (n=785) explored sources of heterogeneity for treatment effects on cytokine levels.
Searches to May 2020 identified 251 trials evaluating 24 interventions with 20 582 participants for inclusion. Most trials had important limitations. Methodological limitations of the included trials and heterogeneity of the treatment effects on cytokine levels between trials limited interpretation. The primary analysis demonstrated inconsistency in the direction of the treatment effects on innate immunity and organ failure or death between interventions. Analyses restricted to important subgroups or trials with fewer limitations showed similar results. Meta-regression, pooling available data from all trials, demonstrated no association between the direction of the treatment effects on inflammatory cytokines and organ injury or death. The analysis of individual patient data demonstrated heterogeneity in the association between the cytokine response and organ injury after cardiac surgery for people >75 yr old and those with some chronic diseases.
The certainty of the evidence for a causal relationship between innate immune system activation and organ injury after cardiac surgery is low.
Background
Organ injury is a common and severe complication of cardiac surgery that contributes to the majority of deaths. There are no effective treatment or prevention strategies. It has been ...suggested that innate immune system activation may have a causal role in organ injury. A wide range of organ protection interventions targeting the innate immune response have been evaluated in randomised controlled trials (RCTs) in adult cardiac surgery patients, with inconsistent results in terms of effectiveness.
Objectives
The aim of the review was to summarise the results of RCTs of organ protection interventions targeting the innate immune response in adult cardiac surgery. The review considered whether the interventions had a treatment effect on inflammation, important clinical outcomes, or both.
Search methods
CENTRAL, MEDLINE, Embase, conference proceedings and two trial registers were searched on October 2022 together with reference checking to identify additional studies.
Selection criteria
RCTs comparing organ protection interventions targeting the innate immune response versus placebo or no treatment in adult patients undergoing cardiac surgery where the treatment effect on innate immune activation and on clinical outcomes of interest were reported.
Data collection and analysis
Searches, study selection, quality assessment, and data extractions were performed independently by pairs of authors. The primary inflammation outcomes were peak IL‐6 and IL‐8 concentrations in blood post‐surgery. The primary clinical outcome was in‐hospital or 30‐day mortality. Treatment effects were expressed as risk ratios (RR) and standardised mean difference (SMD) with 95% confidence intervals (CI). Meta‐analyses were performed using random effects models, and heterogeneity was assessed using I2.
Main results
A total of 40,255 participants from 328 RCTs were included in the synthesis. The effects of treatments on IL‐6 (SMD ‐0.77, 95% CI ‐0.97 to ‐0.58, I2 = 92%) and IL‐8 (SMD ‐0.92, 95% CI ‐1.20 to ‐0.65, I2 = 91%) were unclear due to heterogeneity. Heterogeneity for inflammation outcomes persisted across multiple sensitivity and moderator analyses. The pooled treatment effect for in‐hospital or 30‐day mortality was RR 0.78, 95% CI 0.68 to 0.91, I2 = 0%, suggesting a significant clinical benefit. There was little or no treatment effect on mortality when analyses were restricted to studies at low risk of bias. Post hoc analyses failed to demonstrate consistent treatment effects on inflammation and clinical outcomes. Levels of certainty for pooled treatment effects on the primary outcomes were very low.
Authors' conclusions
A systematic review of RCTs of organ protection interventions targeting innate immune system activation did not resolve uncertainty as to the effectiveness of these treatments, or the role of innate immunity in organ injury following cardiac surgery.
Cenp-F is an unusual kinetochore protein in that it localizes to the nuclear matrix in interphase and the nuclear envelope at the G2/M transition; it is farnesylated and rapidly degraded after ...mitosis. We have recently shown that farnesylation of Cenp-F is required for G2/M progression, its localization to kinetochores, and its degradation. However, the role Cenp-F plays in mitosis has remained enigmatic. Here we show that, following repression of Cenp-F by RNA interference (RNAi), the processes of metaphase chromosome alignment, anaphase chromosome segregation and cytokinesis all fail. Although kinetochores attach to microtubules in Cenp-F-deficient cells, the oscillatory movements that normally occur following K-fibre formation are severely dampened. Consistently, inter-kinetochore distances are reduced. In addition, merotelic associations are observed, suggesting that whereas kinetochores can attach microtubules in the absence of Cenp-F, resolving inappropriate interactions is inhibited. Repression of Cenp-F does not appear to compromise the spindle checkpoint. Rather, the chromosome alignment defect induced by Cenp-F RNA interference is accompanied by a prolonged mitosis, indicating checkpoint activation. Indeed, the prolonged mitosis induced by Cenp-F RNAi is dependent on the spindle checkpoint kinase BubR1. Surprisingly, chromosomes in Cenp-F-deficient cells frequently show a premature loss of chromatid cohesion. Thus, in addition to regulating kinetochore-microtubule interactions, Cenp-F might be required to protect centromeric cohesion prior to anaphase commitment. Intriguingly, whereas most of the sister-less kinetochores cluster near the spindle poles, some align at the spindle equator, possibly through merotelic or lateral orientations.
N‐Terminal Kinesins: Many and Various Wozniak, Marcin J.; Milner, Roy; Allan, Viki
Traffic (Copenhagen, Denmark),
June 2004, 2004-Jun, 2004-06-00, 20040601, Letnik:
5, Številka:
6
Journal Article
Recenzirano
Odprti dostop
Molecular motors are a fascinating group of proteins that have vital roles in a huge variety of cellular processes. They all share the ability to produce force through the hydrolysis of adenosine ...triphosphate, and fall into classes groups: the kinesins, myosins and the dyneins. The kinesin superfamily itself can be split into three major groups depending on the position of the motor domain, which is localized N‐terminally, C‐terminally, or internally. This review focuses on the N‐terminal kinesins, providing a brief overview of their roles within the cell, and illustrating recent key developments in our understanding of how these proteins function.
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