This paper characterizes the actual science performance of the James Webb Space Telescope (JWST), as determined from the six month commissioning period. We summarize the performance of the spacecraft, telescope, science instruments, and ground system, with an emphasis on differences from pre-launch expectations. Commissioning has made clear that JWST is fully capable of achieving the discoveries for which it was built. Moreover, almost across the board, the science performance of JWST is better than expected; in most cases, JWST will go deeper faster than expected. The telescope and instrument suite have demonstrated the sensitivity, stability, image quality, and spectral range that are necessary to transform our understanding of the cosmos through observations spanning from near-earth asteroids to the most distant galaxies.

Comparison of continuous versus intermittent (every 12 h bolus) infusion of a high-purity Factor VIII concentrate in 12 severe hemophilia A patients undergoing surgical procedures indicated that a higher (50 u/dl versus 35 u/dl) minimal plasma level was seen with the same amount of product when given continuously. A continuous VIII concentrate infusion of 2 u/kg/h produces a mean VIIIc level of about 50 u/dl or, alternatively, about 0.04 u/kg/h raises the VIIIc level by 1 u/dl (1%). None of the patients showed any abnormal bleeding. Higher plasma levels of VIIIc were noted by the two-stage VIIIc assay than by the one-stage VIIIc assay. Fibrinogen levels were normal or only slightly elevated, and the monomer test was consistently negative.

Desmopressin (DDAVP), a synthetic vasopressin, temporarily corrects bleeding abnormalities associated with mild hemophilia A, von Willebrand disease, and disorders of platelet function. The side effects of DDAVP are considered benign although most of its use has been in adults and older children. We report four children under the age of 2 years who became hyponatremic after intravenous DDAVP administration (0.3 microgram/kg). Three of them developed grand mal seizures. A review of the literature and these cases indicate that associated risk factors for hyponatremia after DDAVP administration include stress, surgery, anesthesia and narcotics (endogenous release of antidiuretic hormone), vomiting (loss of Na+), liver disease (hindered metabolism of DDAVP), renal tubular acidosis (chronically low serum Na+), multiple doses of DDAVP, and overhydration with hyponatremic fluids. DDAVP is not a benign drug in this age group and shows a serious potential for hyponatremia and seizures. Fluid restriction, avoidance of hyponatremic solutions, and close monitoring of serum electrolytes and urine output for at least 15-20 hr after the administration of DDAVP, when used in children under the age of 2 years, is warranted.

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SummaryTwenty-five preterm newborns were given bolus infusions of sodium heparin (100 units/kg) and plasma heparin levels were assayed at 5,20,40,90, and 150 min. Eight normal adults received a 75 units/kg bolus of heparin and levels were assayed at 5,30,60, 120, 180, and 240 min. In comparison with the adult data (mean adult plasma heparin half life (T%) = 63.3 min), the newborn infants demonstrated a significantly shorter plasma heparin half life (TYz = 35.5 min in group I, 33 to 36 wk gestation; 35.5 min in group 11,29 to 32 wk gestation; and 41.6 min in group III,25 to 28 wk gestation), as demonstrated by a chromogenic heparin assay. The newborn groups had a larger volume of distribution (Vd) of heparin which varied inversely with gestational age (Vd = 36.6 ml/ kg in the adults, 57.8 ml/kg in group I, 73.3 ml/kg in group 11, and 81.0 ml/kg in group I11 babies. Heparin clearance (CI) was significantly greater in all newborn groups when compared with the adult ( C I~d~l t = 0.43 ml/kg/min; Clc,l = 1.37 ml/kg/min; C l c r l~ = 1.43 ml/kg/min; and C~G,III = 1.49 ml/kg/min). A one-stage clotting assay for heparin generated similar results, although infant plasma heparin levels were slightly higher by this assay. Before heparin administration, the mean antithrombin 111 antigen (AT-111 Ag) of the babies was 26.5% of normal adult and was not further decreased 90 min after the heparin bolus. SpeculationThe larger volume of distribution of heparin could require a greater loading dose per kg body weight to achieve a desired plasma level and the more rapid plasma clearance could necessitate higher infusion rates to maintain a desired plasma heparin level in newborn infants. The authors speculate that the study findings are the additive result of the more rapid metabolic rate of the newborn and the physiologically low circulating levels of antithrombin 111.Although thrombotic episodes in the newborn are frequently recognized (2,5,18,19,20,26), therapeutic heparinization is often difficult to achieve (27), and published results have indicated both increased (10) and decreased (16) sensitivity to heparin. To date, scant data are available regarding heparin metabolism or plasma clearance for the neonate (21). Heparin kinetics after a single intravenous bolus dose have been studied in adults utilizing prolongation of clotting parameters (9, 17) and, more recently, measurements of plasma heparin levels (23). To provide the basisfor estimations of heparin dosage, the present study was performed comparing plasma heparin disappearance in newborns with that in adults after a single bolus heparin infusion. MATERIALS AND METHODSThe heparin preparation utilized was porcine intestinal sodium heparin, 1000 units/ml (Panheparin, Abbott Laboratories), and all study heparin was of one lot, no. 86-196-AF.Heparin assays and AT-I11 Ag were performed on plasma procured by the two-syringe technique. For adults, one volume of 101 0.1 M buffered citrate anticoagulant to nine volumes of whole blood was used. In all newborns a central arterial he...