Baseline chest radiographic features of HIV-infected children eligible for antiretroviral therapy

Background. South Africa’s HIV mortality is primarily due to pulmonary disease. No evidence exists regarding a correlation between specific chest radiographic patterns and CD4 levels of immunity in HIV-infected children.Objectives. We aimed to determine the prevalence of specific radiographic features in HIV-infected children initiating antiretroviral therapy (ART) to develop a guideline of expected baseline radiographic appearances, and the radiographic features that predominate at specific levels of immune suppression (defined by CD4 percentage ranges), which would narrow the radiological differential diagnosis.Method. Retrospective review of the baseline chest radiographs of 92 consecutive paediatric outpatients initiating ART.Results. Normal radiographs were reported in 54% of patients. Those with radiographic abnormalities had parenchymal disease (34%), mediastinal disease (22%) and pleural disease (1%). Parenchymal disease was predominantly air space (28%), and mediastinal disease was predominantly cardiomegaly (21%); lymphadenopathy was rare (1%). Radiological appearances of TB were seen in 9% of patients. A statistically significant association was shown between immune suppression and air space disease (p=0.049) with a relative risk of 0.46 (95% CI 0.24 - 0.88) for air space disease in immune-suppressed children. This association was independent of age.Conclusion. Baseline chest radiographs in paediatric outpatients presenting for initiation of ART are predominantly normal, but also demonstrate a significant number of pathological radiological features – primarily air space disease and cardiomegaly. The only statistically significant association between radiographic features and immune suppression was air space disease, which correlated with a higher level of immunity.S Afr Med J 2011;101:829-834

The injured snowman

Total anomalous pulmonary venous return (TAPVR) is a rare congenital cardiac defect that may present with cyanosis, cardiac failure and failure to thrive in infancy. TAPVR type 1 has a typical radiographic appearance of the heart termed the snowman. We present a case of an infant with TAPVR type 1 with injuries in keeping with non-accidental injury (NAI) to highlight that children with chronic diseases are at greater risk of this kind of injury and that radiographic evaluation of the chest in cardiac disease plays a role beyond demonstrating the heart and vasculature of the chest

Atypical teratoid/rhabdoid tumour in a supratentorial location: a report of two cases

Atypical teratoid/rhabdoid tumour of the central nervous system is a rare, highly aggressive childhood malignancy. The age of presentation is usually <2 years, but this tumour may occur in other age groups. The typical location is the posterior fossa, with supratentorial origin less common. We present two cases of atypical teratoid/rhabdoid tumours, with the suprasellar location of one case proving to be a diagnostic radiological challenge

Lipid-Induced Toxicity Stimulates Hepatocytes to Release Angiogenic Microparticles That Require Vanin-1 for Uptake by Endothelial Cells.

Angiogenesis is a key pathological feature of experimental and human steatohepatitis, a common chronic liver disease that is associated with obesity. We demonstrated that hepatocytes generated a type of membrane-bound vesicle, microparticles, in response to conditions that mimicked the lipid accumulation that occurs in the liver in some forms of steatohepatitis and that these microparticles promoted angiogenesis. When applied to an endothelial cell line, medium conditioned by murine hepatocytes or a human hepatocyte cell line exposed to saturated free fatty acids induced migration and tube formation, two processes required for angiogenesis. Medium from hepatocytes in which caspase 3 was inhibited or medium in which the microparticles were removed by ultracentrifugation lacked proangiogenic activity. Isolated hepatocyte-derived microparticles induced migration and tube formation of an endothelial cell line in vitro and angiogenesis in mice, processes that depended on internalization of microparticles. Microparticle internalization required the interaction of the ectoenzyme Vanin-1 (VNN1), an abundant surface protein on the microparticles, with lipid raft domains of endothelial cells. Large quantities of hepatocyte-derived microparticles were detected in the blood of mice with diet-induced steatohepatitis, and microparticle quantity correlated with disease severity. Genetic ablation of caspase 3 or RNA interference directed against VNN1 protected mice from steatohepatitis-induced pathological angiogenesis in the liver and resulted in a loss of the proangiogenic effects of microparticles. Our data identify hepatocyte-derived microparticles as critical signals that contribute to angiogenesis and liver damage in steatohepatitis and suggest a therapeutic target for this condition

Recommendations for the diagnosis of pediatric tuberculosis

Tuberculosis (TB) is still the world's second most frequent cause of death due to infectious diseases after HIV infection, and this has aroused greater interest in identifying and managing exposed subjects, whether they are simply infected or have developed one of the clinical variants of the disease. Unfortunately, not even the latest laboratory techniques are always successful in identifying affected children because they are more likely to have negative cultures and tuberculin skin test results, equivocal chest X-ray findings, and atypical clinical manifestations than adults. Furthermore, they are at greater risk of progressing from infection to active disease, particularly if they are very young. Consequently, pediatricians have to use different diagnostic strategies that specifically address the needs of children. This document describes the recommendations of a group of scientific societies concerning the signs and symptoms suggesting pediatric TB, and the diagnostic approach towards children with suspected disease

Dynamic replication strategies in data grid systems: A survey

In data grid systems, data replication aims to increase availability, fault tolerance, load balancing and scalability while reducing bandwidth consumption, and job execution time. Several classification schemes for data replication were proposed in the literature, (i) static vs. dynamic, (ii) centralized vs. decentralized, (iii) push vs. pull, and (iv) objective function based. Dynamic data replication is a form of data replication that is performed with respect to the changing conditions of the grid environment. In this paper, we present a survey of recent dynamic data replication strategies. We study and classify these strategies by taking the target data grid architecture as the sole classifier. We discuss the key points of the studied strategies and provide feature comparison of them according to important metrics. Furthermore, the impact of data grid architecture on dynamic replication performance is investigated in a simulation study. Finally, some important issues and open research problems in the area are pointed out