MHC class I molecules function to present peptides eight to ten residues
long to the immune system. These peptides originate primarily from a cytosolic
pool of proteins through the actions of ...proteasomes, and are
transported into the endoplasmic reticulum, where they assemble with nascent
class I molecules. Most peptides are generated from proteins
that are apparently metabolically stable. To explain this, we previously proposed
that peptides arise from proteasomal degradation of defective ribosomal products
(DRiPs). DRiPs are polypeptides that never attain native structure owing to
errors in translation or post-translational processes necessary for proper
protein folding. Here we show, first, that DRiPs constitute
upwards of 30% of newly synthesized proteins as determined in a variety of
cell types; second, that at least some DRiPs represent ubiquitinated proteins;
and last, that ubiquitinated DRiPs are formed from human immunodeficiency
virus Gag polyprotein, a long-lived viral protein that serves as a source
of antigenic peptides.
Much controversy exists about the optimal management of a patent ductus arteriosus (PDA) in preterm infants, especially in those born at a gestational age (GA) less than 28 weeks. No causal ...relationship has been proven between a (haemodynamically significant) PDA and neonatal complications related to pulmonary hyperperfusion and/or systemic hypoperfusion. Although studies show conflicting results, a common understanding is that medical or surgical treatment of a PDA does not seem to reduce the risk of major neonatal morbidities and mortality. As the PDA might have closed spontaneously, treated children are potentially exposed to iatrogenic adverse effects. A conservative approach is gaining interest worldwide, although convincing evidence to support its use is lacking.
This multicentre, randomised, non-inferiority trial is conducted in neonatal intensive care units. The study population consists of preterm infants (GA < 28 weeks) with an echocardiographic-confirmed PDA with a transductal diameter > 1.5 mm. Early treatment (between 24 and 72 h postnatal age) with the cyclooxygenase inhibitor (COXi) ibuprofen (IBU) is compared with an expectative management (no intervention intended to close a PDA). The primary outcome is the composite of mortality, and/or necrotising enterocolitis (NEC) Bell stage ≥ IIa, and/or bronchopulmonary dysplasia (BPD) defined as the need for supplemental oxygen, all at a postmenstrual age (PMA) of 36 weeks. Secondary outcome parameters are short term sequelae of cardiovascular failure, comorbidity and adverse events assessed during hospitalization and long-term neurodevelopmental outcome assessed at a corrected age of 2 years. Consequences regarding health economics are evaluated by cost effectiveness analysis and budget impact analysis.
As a conservative approach is gaining interest, we investigate whether in preterm infants, born at a GA less than 28 weeks, with a PDA an expectative management is non-inferior to early treatment with IBU regarding to the composite outcome of mortality and/or NEC and/or BPD at a PMA of 36 weeks.
This trial is registered with the Dutch Trial Register NTR5479 (registered on 19 October 2015), the registry sponsored by the United States National Library of Medicine Clinicaltrials.gov NCT02884219 (registered May 2016) and the European Clinical Trials Database EudraCT 2017-001376-28 .
Intrabony periodontal defects are a frequent complication of periodontitis and, if left untreated, may negatively affect long‐term tooth prognosis. The optimal outcome of treatment in intrabony ...defects is considered to be the absence of bleeding on probing, the presence of shallow pockets associated with periodontal regeneration (i.e. formation of new root cementum with functionally orientated inserting periodontal ligament fibers connected to new alveolar bone) and no soft‐tissue recession. A plethora of different surgical techniques, often including implantation of various types of bone graft and/or bone substitutes, root surface demineralization, guided tissue regeneration, growth and differentiation factors, enamel matrix proteins or various combinations thereof, have been employed to achieve periodontal regeneration. Despite positive observations in animal models and successful outcomes reported for many of the available regenerative techniques and materials in patients, including histologic reports, robust information on the degree to which reported clinical improvements reflect true periodontal regeneration does not exist. Thus, the aim of this review was to summarize, in a systematic manner, the available histologic evidence on the effect of reconstructive periodontal surgery using various types of biomaterials to enhance periodontal wound healing/regeneration in human intrabony defects. In addition, the inherent problems associated with performing human histologic studies and in interpreting the results, as well as certain ethical considerations, are discussed. The results of the present systematic review indicate that periodontal regeneration in human intrabony defects can be achieved to a variable extent using a range of methods and materials. Periodontal regeneration has been observed following the use of a variety of bone grafts and substitutes, guided tissue regeneration, biological factors and combinations thereof. Combination approaches appear to provide the best outcomes, whilst implantation of alloplastic material alone demonstrated limited, to no, periodontal regeneration.
Objective: To describe the steps of ensuring measurement fidelity of core clinical measures in a five-country study on brain signatures of obsessive-compulsive disorder (OCD). Method: We collected ...data using standardized instruments, which included the Yale-Brown Obsessive-Compulsive Scale (YBOCS), the Dimensional YBOCS (DYBOCS), the Brown Assessment of Beliefs Scale (BABS), the 17-item Hamilton Depression Scale (HAM-D), the Hamilton Anxiety Scale (HAM-A), and the Structured Clinical Interview for DSM-5 (SCID). Steps to ensure measurement fidelity included translating instruments, developing a clinical decision manual, and continuing reliability training with 11-13 transcripts of each instrument by 13 independent evaluators across sites over 4 years. We use multigroup confirmatory factor analysis (MGCFA) to report interrater reliability (IRR) among the evaluators and factor structure for each scale in 206 participants with OCD. Results: The overall IRR for most scales was high (ICC > 0.94) and remained good to excellent throughout the study. Consistent factor structures (configural invariance) were found for all instruments across the sites, while similarity in the factor loadings for the items (metric invariance) could be established only for the DYBOCS and the BABS. Conclusions: It is feasible to achieve measurement fidelity of clinical measures in multisite, multilinguistic global studies, despite the challenges inherent to such endeavors. Future studies should not only report IRR but also consider reporting methods of standardization of data collection and measurement invariance to identify factor structures of core clinical measures.
Key Points
Question: What is the key question this article addresses? This article addresses the challenges and effectiveness of ensuring the fidelity of clinical measurements in a global study. Findings: What are the primary findings? Reliability among multiple independent evaluators was very high and the core clinical measures showed reasonable consistency across sites. Importance: What are the key scientific and practical implications of the findings? Ensuring measurement fidelity in a global study can be challenging, but rigorous procedures yield consistent high-quality data. Next Steps: What directions should be explored in future research? Future international collaborations should refine procedures for ensuring measurement fidelity by reporting both reliability and consistency in measurements throughout the study and across sites.
Background
Hyperkalemic cardiac arrest is a potential complication of massive transfusion in children. Our objective was to identify risk factors and potential preventive measures by reviewing the ...literature on transfusion‐associated hyperkalemic cardiac arrest (TAHCA) in the pediatric population.
Study Design and Methods
Literature searches were performed in MEDLINE and the Cochrane Database of Systematic Reviews.
Results
We identified nine case reports of pediatric patients who had experienced cardiac arrest during massive transfusion. Serum potassium concentration was reported in eight of those reports; the mean was 9.2 ± 1.8 mmol/L. Risk factors for TAHCA noted in the case reports included infancy (n = 6); age of red blood cells (RBCs; n = 5); site of transfusion (n = 5); and the presence of comorbidities such as hyperkalemia, hypocalcemia, acidemia, and hypotension (n = 9). We also identified 13 clinical studies that examined potassium levels associated with transfusion. Of those 13, five studied routine transfusion, two were registries, and six examined massive transfusion.
Conclusions
Key points identified from this literature search are as follows: 1) Case reports are skewed toward infants and neonates in particular and 2) the rate of blood transfusion, more so than total volume, cardiac output, and the site of infusion, are key factors in the development of TAHCA. Measures to reduce the risk of TAHCA in young children include anticipating and replacing blood loss before significant hemodynamic compromise occurs, using larger‐bore (>23‐gauge) peripheral intravenous catheters rather than central venous access, checking and correcting electrolyte abnormalities frequently, and using fresher RBCs for massive transfusion.
The recent insight that inflammation contributes to the development of atherosclerosis and type 2 diabetes mellitus constitutes a major breakthrough in understanding the mechanisms underlying these ...conditions. In addition, it opens the way for new therapeutic approaches that might eventually decrease the prevalence of these public health problems. Tumor necrosis factor-α (TNF-α) has been shown to play a key role in these processes and thus might be a potential therapeutic target. Increased concentrations of TNF-α are found in acute and chronic inflammatory conditions (e.g., trauma, sepsis, infection, rheumatoid arthritis), in which a shift toward a proatherogenic lipid profile and impaired glucose tolerance occurs. Although therapeutic blockade of TNF-α worsens the prognosis in patients with abscesses and granulomatous infections, this strategy is highly beneficial in the case of chronic inflammatory conditions, including rheumatoid arthritis. Current investigations assessing the impact of anti-TNF agents on intermediary metabolism suggest that TNF-α blockade may improve insulin resistance and lipid profiles in patients with chronic inflammatory diseases.
The ultimate goals of periodontal therapy remain the complete regeneration of those periodontal tissues lost to the destructive inflammatory‐immune response, or to trauma, with tissues that possess ...the same structure and function, and the re‐establishment of a sustainable health‐promoting biofilm from one characterized by dysbiosis. This volume of Periodontology 2000 discusses the multiple facets of a transition from therapeutic empiricism during the late 1960s, toward regenerative therapies, which is founded on a clearer understanding of the biophysiology of normal structure and function. This introductory article provides an overview on the requirements of appropriate in vitro laboratory models (e.g. cell culture), of preclinical (i.e. animal) models and of human studies for periodontal wound and bone repair. Laboratory studies may provide valuable fundamental insights into basic mechanisms involved in wound repair and regeneration but also suffer from a unidimensional and simplistic approach that does not account for the complexities of the in vivo situation, in which multiple cell types and interactions all contribute to definitive outcomes. Therefore, such laboratory studies require validatory research, employing preclinical models specifically designed to demonstrate proof‐of‐concept efficacy, preliminary safety and adaptation to human disease scenarios. Small animal models provide the most economic and logistically feasible preliminary approaches but the outcomes do not necessarily translate to larger animal or human models. The advantages and limitations of all periodontal‐regeneration models need to be carefully considered when planning investigations to ensure that the optimal design is adopted to answer the specific research question posed. Future challenges lie in the areas of stem cell research, scaffold designs, cell delivery and choice of growth factors, along with research to ensure appropriate gingival coverage in order to prevent gingival recession during the healing phase.
The endothelial glycoprotein thrombomodulin regulates coagulation, vascular inflammation and apoptosis. In the kidney, thrombomodulin protects the glomerular filtration barrier by eliciting crosstalk ...between the glomerular endothelium and podocytes. Several glomerular pathologies are characterized by a loss of glomerular thrombomodulin. In women with pre-eclampsia, serum levels of soluble thrombomodulin are increased, possibly reflecting a loss from the glomerular endothelium. We set out to investigate whether thrombomodulin expression is decreased in the kidneys of women with pre-eclampsia and rats exposed to an angiogenesis inhibitor. Thrombomodulin expression was examined using immunohistochemistry and qPCR in renal autopsy tissues collected from 11 pre-eclamptic women, 22 pregnant controls and 11 hypertensive non-pregnant women. Further, kidneys from rats treated with increasing doses of sunitinib or sunitinib in combination with endothelin receptor antagonists were studied. Glomerular thrombomodulin protein levels were increased in the kidneys of women with pre-eclampsia. In parallel, in rats exposed to sunitinib, glomerular thrombomodulin was upregulated in a dose-dependent manner, and the upregulation of glomerular thrombomodulin preceded the onset of histopathological changes. Selective ET
R blockade, but not dual ET
R blockade, normalised the sunitinib-induced increase in thrombomodulin expression and albuminuria. We propose that glomerular thrombomodulin expression increases at an early stage of renal damage induced by antiangiogenic conditions. The upregulation of this nephroprotective protein in glomerular endothelial cells might serve as a mechanism to protect the glomerular filtration barrier in pre-eclampsia.
Physicians and parents of critically ill neonates and children receiving intensive care have to make decisions on the child's behalf. Throughout the child's illness and treatment trajectory, ...adequately discussing uncertainties with parents is pivotal because this enhances the quality of the decision-making process and may positively affect the child's and parents' well-being. We investigated how physicians discuss uncertainty with parents and how this discussion evolves over time during the trajectory.
We asked physicians working in the NICU and PICU of 3 university medical centers to audio record their conversations with parents of critically ill children from the moment doubts arose whether treatment was in the child's best interests. We qualitatively coded and analyzed the anonymized transcripts, thereby using the software tool MAXQDA 2020.
Physicians were found to adapt the way they discussed uncertainty with parents to the specific phase of the child's illness and treatment trajectory. When treatment options were still available, physicians primarily focused on uncertainty related to diagnostic procedures, treatment options, and associated risks and effects. Particularly when the child's death was imminent, physicians had less "scientific" guidance to offer. They eliminated most uncertainty and primarily addressed practical uncertainties regarding the child's dying process to offer parents guidance.
Our insights may increase physicians' awareness and enhance their skills in discussing uncertainties with parents tailored to the phase of the child's illness and treatment trajectory and to parental needs in each specific phase.
MHC class I molecules predominantly bind to peptides derived from a cytosolic pool of polypeptides. Little is known about the nature of the polypeptides that serve as substrates for peptidogenic ...cytosolic proteases. We propose that a significant source of self and viral peptides are defective ribosomal products (DRiPs), which consist of prematurely terminated polypeptides and misfolded polypeptides produced from translation of bona fide mRNAs in the proper reading frame. DRiPs are produced entropically, due to the inevitable imperfections inherent to protein synthesis or folding. To accelerate recognition of cells harboring intracellular parasites such as viruses, DRiP formation may be enhanced by changes in the cellular physiology induced by infection or by exposure of cells to cytokines released at the site of inflammation.
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