Complications with proceduresExchange transfusions for hyperbilirubinemia were

a very common procedure in newborns before the developmentof treatment with anti-Rh antibody to prevent Rh antigensensitization. The introduction of phototherapy has furtherreduced the need for exchange transfusion such that it is nowa rare procedure even in a busy neonatal intensive care unit. It isoften difficult to find the parts for the blood warmer or a nursewho is familiar with recording each volume exchanged. In thisissue of The Journal, Patra et al report the frequent occurrenceof complications with exchange transfusions in the current era.Fortunately, most of the complications were not serious. How-ever, their experience points out the widespread decreasedexposure of pediatricians in training to domany procedures thatused to be routine. Fewer procedures are good for children,unless a procedure needs to be done by personnel withoutsufficient experience.

—Alan H. Jobe, MD, PhDPage 626

Exercise improves vascular functionWith the prevalence and severity of obesity increasing in

children and adolescents in the United States, there is concernthat this may lead to atherosclerosis and ultimately coronaryheart disease. In this issue of The Journal,Watts et al report onthe results of a study of 8 weeks of exercise training in obesechildren. They found that flow-mediated dilation of thebrachial artery, ameasure of endothelial function, was impairedrelative to matched control subjects. After 8 weeks of exercisetraining, there was no significant change in body mass index.However, they did find a significant improvement in endo-thelial function. These results are important because theyunderscore the importance of physical activity in the treatmentof obesity even when body mass index is not improved. It alsoemphasizes that beneficial effects can be observed in as shorta time period as 2 months.

—Stephen R. Daniels, MD, PhDPage 620

New treatments for lysosomalstorage disorders

This issue of The Journal contains several impor-tant papers regarding the treatment of storage disorders.

Grewal et al report effective treatment of a-mannosidosis by allogeneic hematopoietic stem celltransplantation in four patients at the University ofMinnesota (p 569). All four patients responded well withstabilization of their intellectual function, improvementin verbal memory function and adaptive skills in three offour, and improvement in hearing without developmentof any new skeletal abnormalities. They suggest thatearly diagnosis and treatment of a-mannosidosis withstem cell transplantation is effective.

Harmatz et al report the safety and efficacy ofweekly treatment with human recombinant N-acetylgalactosamine 4-sulfatase (rhASB) in humans withmucupolysaccharidosis (MPS) type IV (Maroteaux-Lamy Syndrome) (p 574). Their paper reports the resultsof a randomized double-blind study in 6 patientscompleting between 24 and 48 weeks of therapy. Thedrug was well tolerated and treatment was associatedwith improvement in exercise function and jointfunction. The greatest improvement was seen in patientswith advanced disease receiving a high dose of rhASB.

Wraith et al report the results of a randomized,double-blind, placebo-controlled trial of human rec-ombinant a-L-iduronidase (Laronidase) for MPS I (p581). Forty-five patients in this multinational studyreceived 100 U/kg of a-L-iduronidase or placebo weeklyfor 26 weeks. The patients receiving the active drugshowed improvement in pulmonary function andexercise performance; they also had reduced hepatomeg-aly and urinary glycosaminoglycans. In more severelyaffected children there was also improvement in sleepapnea. The medication was well tolerated in spite ofpatients developing IgG antibodies. The authors con-clude that, in patients with MPS I, a-L-iduronidasesignificantly improves respiratory function and physicalcapacity with reduced storage of glycosaminoglycans,and it has a favorable safety profile.

This last article is commented on in an editorialentitled ‘‘Treatment of respiratory system (not just lung!)abnormalities in mucopolysaccharidosis I,’’ (p 561) byJulian Allen, MD, from Children’s Hospital ofPhiladelphia.

—Robert W. Wilmott, MD

2A May 2004 The Journal of Pediatrics