Idiopathic collapsing glomerulopathy in children.

Idiopathic collapsing glomerulopathy (ICG) is a clinically and pathologically distinct variant of focal segmental glomerulosclerosis, characterized clinically by rapid progression of renal insufficiency, a male and African-American racial predominance, and pathologically by segmental glomerular collapse, visceral epithelial cell hypertrophy and hyperplasia, and the absence of endothelial tubuloreticular inclusions. Pathologically similar lesions have been reported in adult and pediatric patients with human immunodeficiency virus (HIV) infection and/or intravenous (IV) drug abuse. Most patients with ICG who have been reported in the literature are adults. Six children with ICG were retrospectively identified (two from East Carolina University, four from University of North Carolina-Chapel Hill). Clinical data and renal biopsy findings were reviewed for all patients. All six patients were male; five African-American and one Hispanic. Ages ranged from 2 to 17 years (mean 12 years). Steroid-resistant nephrotic syndrome was the presenting clinical finding. Average 24-h urine protein excretion was 6.3 g (range 3.2-15 g). Five patients were serologically negative for HIV infection (one patient not tested) and none had a history of IV drug abuse or known HIV risk factors. Progression to end-stage renal insufficiency in two patients within 1 year of biopsy required renal transplantation, and within 1 month of biopsy one patient required dialysis. We report a series of pediatric patients with ICG, an aggressive variant of focal segmental glomerulosclerosis. ICG in children is similar clinically and pathologically to this disease in adult patients.

Primary databases for forest ecosystem management-examples from Ontario and possibilities for Canada: NatGRID.

This paper identifies some scientific impediments to ecosystem management and describes bio-physical databases required to help systematically and empirically address the ecological sustainability challenge. Examples are drawn from ongoing work in Ontario. This work has implications for efforts in ecological land classification, landscape ecology, more efficient locating of research and monitoring plots, wildlife management and ultimately trade-off analyses. We conclude with the recommendation that the key primary databases, as currently evolving for Ontario, could and should be developed nationally, thereby creating a "NatGRID database", i.e., Nationally Georeferenced Resource Information for Decision-making. NatGRID could be used to help address, in a more quantitative manner, fundamental questions regarding ecological sustainability and trade-offs in forest management.

Distinct isoforms of the CD45 protein-tyrosine phosphatase differentially regulate interleukin 2 secretion and activation signal pathways involving Vav in T cells.

The CD45 family of transmembrane protein-tyrosine phosphatases plays a crucial role in the regulation of lymphocyte activation by coupling activation signals from antigen receptors to the signal transduction apparatus. Multiple CD45 isoforms, generated through regulated alternative mRNA splicing, differ only in the length and glycosylation of their extracellular domains. Differential distribution of these isoforms defines subsets of T cells having distinct functions and activation requirements. While the requirement for the intracellular protein-tyrosine phosphatase domains has been documented, the physiological role of the extracellular domains remains elusive. Here we report the generation of CD45-antisense transfected Jurkat T cell clones that lack CD45 or have been reconstituted to uniquely express either the smallest, CD45(0), or the largest, CD45(ABC), isoform. These cells exhibited marked isoform-dependent differences in IL-2 production and tyrosine phosphorylation of cellular proteins, including Vav after anti-CD3 stimulation. These results demonstrate that the distinct CD45 extracellular domains differentially regulate T cell receptor-mediated signaling pathways. Furthermore, these findings suggest that alterations in CD45 isoform expression by individual T cells during thymic ontogeny and after antigen exposure in the periphery directly affects the signaling pathways utilized.

An unusual skin lesion in a pediatric patient with Wegener's granulomatosis.

Cutaneous manifestations occur in a significant number of patients with Wegener's granulomatosis (WG); however, the presentation and histopathology of these lesions are highly variable and may present problems in diagnosis. We report the presentation of a single large skin lesion in a pediatric patient with a history of WG and the characterization of this lesion by magnetic resonance imaging (MRI) and histopathology. MRI was helpful in delineating the extent of the lesion, although a skin biopsy was necessary to confirm the diagnosis of the vasculitic nature of the lesion.