Giant cell tumor (GCT) of bone is a locally destructive tumor that occurs predominantly in long bones of post-pubertal adolescents and young adults, where it occurs in the epiphysis. The majority are treated by aggressive curettage or resection. Vascular invasion outside the boundary of the tumor can be seen. Metastasis, with identical morphology to the primary tumor, occurs in a few percent of cases, usually to the lung. On occasion GCTs of bone undergo frank malignant transformation to undifferentiated sarcomas. Here we report a case of GCT of bone that at the time of recurrence was found to have undergone malignant transformation. Concurrent metastases were found in the lung, but these were non-transformed GCT.
Aims There has been a growing interest in the use of markers of aerobic physical fitness (VO2max assessed by cardiopulmonary exercise testing (CPET)) in the follow-up of paediatric chronic diseases. The dissemination of CPET in paediatrics requires valid paediatric VO2max reference values to define the upper and lower normal limits. This study aimed to establish VO2max reference Z-scores values, from a large cohort of children representative of the contemporary paediatric population, including those with extreme weights. Methods and results In this cross-sectional study, 909 children aged 5 to 18-years-old from the general French population (development cohort), and 232 children from the general German and US populations (validation cohort) underwent a CPET, following the guidelines on high-quality CPET assessment. Linear, quadratic, and polynomial mathematical regression equations were applied to identify the best VO2max Z-score model. Predicted and observed VO2max values using the VO2maxZ-score model, and the existing linear equations were compared, in both development and validation cohorts. For both sexes, the mathematical model using natural logarithms of VO2max, height, and BMI was the best fit for the data. This Z-score model could be applied to normal and extreme weights and was more reliable than the existing linear equations, in both internal and external validity analyses (https://play.google.com/store/apps/details?id=com.d2l.zscore). Conclusion This study established reference Z-score values for paediatric cycloergometer VO2max using a logarithmic function of VO2max, height and BMI, applicable to normal and extreme weights. Providing Z-scores to assess aerobic fitness in the paediatric population should be useful in the follow-up of children with chronic diseases.
With an in vitro system that used a luminescent strain of Klebsiella pneumoniae to assess bacterial metabolic activity in near-real-time, we investigated the dynamics of complement-mediated attack in healthy individuals and in patients presenting to the emergency department with community-acquired severe sepsis. A novel mathematical/statistical model was developed to simplify light output trajectories over time into two fitted parameters, the rate of complement activation and the delay from activation to the onset of killing. Using Factor B-depleted serum, the alternative pathway was found to be the primary bactericidal effector: In the absence of B, C3 opsonization as measured by flow cytometry did not progress and bacteria proliferated near exponentially. Defects in bacterial killing were easily demonstrable in patients with severe sepsis compared with healthy volunteers. In most patients with sepsis, the rate of activation was higher than in normal subjects but was associated with a prolonged delay between activation and bacterial killing (P , 0.05 for both). Theoretical modeling suggested that this combination of accentuated but delayed function should allow successful bacterial killing but with significantly greater complement activation. The use of luminescent bacteria allowed for the development of a novel and powerful tool for assessing complement immunology for the purposes of mechanistic study and patient evaluation.Keywords: alternative complement pathway; theoretical models; nonlinear dynamics; sepsisThe complement cascade fills a crucial niche in early host defense against bacterial infection. Activating by fully innate means (i.e., through the alternative and mannose-binding lectin pathways) or in conjunction with acquired humoral immunity (via the classical pathway), the system contributes to defense by enzymatically labeling microorganisms for phagocytosis through C3 opsonization, by generating a series of anaphylatoxins that alert cellular defenses to the presence of a pathogen, and, in some instances, by directly killing the invading cell by permeabilizing its cell wall with membrane attack complex (C5b6789 n or MAC).During experimental or human sepsis, globally assessing the complement system is typically done in one of two ways. Most often, traces of previous activation are sought by measuring concentrations of complement proteins (such as C3, which falls with activation) or species elaborated during activation such as C3a, C5a, or soluble MAC (1). Less commonly, function is directly assessed. This is typically done by measuring complement hemolytic activity, with the canonical example being the CH 50 method. CH 50 is known to fall in severe human sepsis and multiorgan failure (2). How best to interpret this capacity (i.e., the complement-mediated cytolysis of an enucleate and otherspecies blood cell fully opsonized by a third species' IgG) in the setting of an overwhelming infection is not self-evident.A more relevant functional assay of the complement system's performance in the presence of...
Children with cDGS should receive thymic transplantion as soon as possible, but prior to this are at risk for nontuberculous mycobacterial infections. Severe, opportunistic infections may require invasive testing for diagnosis in patients with cDGS. Antimicrobial prophylaxis should be considered to prevent disseminated mycobacterial infection in these patients.
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