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Phototherapy with blue fluorescent light is widely employed for treatment of neonatal hyperbilirubinemia. Functional, biochemical, and morphologic changes produced by blue fluorescent light in human platelets were identified and characterized. Platelet-rich plasma was exposed for up to 170 min to amounts of light equivalent to that used in phototherapy of neonatal hyperbilirubinemia. Within 110 min of light exposure, platelets were essentially no longer aggregable by ADP and connective tissue suspension and were depleted of ADP, ATP, and glycogen. Electron photomicrographs revealed these platelets to be swollen, depleted of glycogen granules and organelles, and to have ill-defined membranes. Platelet injury could be accelerated by adding a photosensitizing agent, hematoporphyrin, to platelet samples before exposure. In contrast, control platelets kept in the dark for 170 min or nonirradiated platelets resuspended in irradiated plasma maintained their integrity. The results indicate that platelets are damaged in vitro when exposed to amounts of blue light used in phototherapy.

Platelet function and coagulation studies were performed on 65 children with congenital heart disease (CHD) and five wtih acquired heart disease, varying in age from 2 wk to 17 yr. Approximately 11% of the children with CHD had mild bleeding symptoms, and 9% had prolonged bleeding times, despite normal platelet counts. In 14 of 37 children (37.8%) with cyanotic CHD and four of 28 (14.3%) with the acyanotic variety, platelet aggregation by adenosine diphosphate (ADP), noradrenalin, and connective tissue suspension was impaired. The possibility of a platelet inhibitory factor in plasma was unlikely. Platelet content of ADP was normal, and high concentrations of exogenous ADP produced an improvement in aggregation, suggesting that the disturbance may be due to defective release of intrinsic ADP from the platelets. Impairment in aggregation was correlated with the severity of hypoxemia and polycythemia in cyanotic patients. Coagulation data did not support the concept that disseminated intravascular coagulation is a frequently associated finding in cyanotic CHD. Our findings reveal a disturbance in platelet function, until now, not commonly associated with CHD.

No abstract

To examine the number of renal biopsies in correlation with the pattern of referrals as well as the major categories of renal diseases for the procedure peculiar to children, the data of 100 consecutive percutaneous renal biopsies using disposable biopsy needles under ultrasound guidance in 99 children were reviewed. To examine the risks and accuracy of the procedure the estimated depth of the kidney by ultrasound, the actual biopsy depth, the success rate and the complications were evaluated. With rare exception, 1 core of renal tissue was obtained per single needle insertion; 109 needle insertions yielded 103 cores. Of the specimens 92 per cent contained more than 10 glomeruli. Gross hematuria with the first voiding post-biopsy occurred in 12 per cent of the cases but persisted beyond 24 hours in only 1 per cent. No long-term complications were observed. Percutaneous renal biopsy with the disposable needle guided by ultrasound represents a considerable advance in diagnostic technique and deserves wider application in the evaluation and management of a number of pediatric kidney disorders.