To test the hypothesis that chronic intrauterine pulmonary hypertension (PHTN) compromises pulmonary artery (PA) smooth muscle cell (SMC) O2 sensing, fluorescence microscopy was used to study the effect of an acute increase in Po2 on the cytosolic Ca2+ concentration ([Ca2+]i) of chronically hypoxic subconfluent monolayers of PA SMC in primary culture. PA SMCs were derived from fetal lambs with PHTN due to intrauterine ligation of the ductus arteriosus. Acute normoxia decreased [Ca2+]i in control but not PHTN PA SMC. In control PA SMC, [Ca2+]i increased after Ca2+-sensitive (KCa) and voltage-sensitive (Kv) K+ channel blockade and decreased after diltiazem treatment. In PHTN PA SMC, KCa blockade had no effect, whereas Kv blockade and diltiazem increased [Ca2+]i. Inhibition of sarcoplasmic reticulum Ca2+ ATPase activity caused a greater increase in [Ca2+]i in controls compared with PHTN PA SMC. Conversely, ryanodine caused a greater increase of [Ca2+]i in PHTN compared with control PA SMC. KCa channel mRNA is decreased and Kv channel mRNA is unchanged in PHTN PA SMC compared with controls. We conclude that PHTN compromises PA SMC O2 sensing, alters intracellular Ca2+ homeostasis, and changes the predominant ion channel that determines basal [Ca2+]i from KCa to Kv.

Troponins are highly sensitive and specific biochemical markers of myocardial injury that are released into the circulation during myocardial ischemia. We describe changes in cardiac troponin I (cTnI) prior to and following clinical evidence of severe myocardial dysfunction in a child with hemolytic uremic syndrome (HUS). A previously healthy, 22-month-old girl presented with typical HUS and stool cultures positive for Escherichia coli O157:H7. She required dialysis, blood and platelet transfusions, and insulin for HUS-related diabetes mellitus. On the 6th hospital day she had sudden circulatory collapse with a blood pressure of 70/40 mmHg and an oxygen saturation of 88%. She responded rapidly to emergency resuscitation but had diminished left ventricular function (ejection fraction 18%). Four days after the acute event an echocardiogram showed normal ventricular size and contractility. She underwent hemodialysis for 22 days, and renal function was normal after 33 days. cTnI levels were measured with a microparticle enzyme immunoassay. cTnI was normal (>0.4 microg/l) 32 h prior to cardiac collapse, mildly increased (2.1 microg/l) 8 h before the cardiac collapse, severely elevated shortly after the cardiac event (43.1 microg/l), and peaked (140.6 microg/l) at 24 h. It then fell gradually and was normal at discharge. These results suggest that measurement of cTnI may be a useful predictor of cardiac involvement in severely affected children with HUS.

The threshold between normal body temperature and fever has not been clear. The American Academy of Pediatrics (AAP) as well as the European Centre for Pediatric and Adolescent Medicine (ECPA) guideline defines fever as a temperature >100.4°F (38.0°C) [Wyckoff, 2009;Niehues, 2013] to be the current practice, regardless of age. They also recommend use of rectal thermometers in children <3 years. Several currently commercialized thermometers use such fixed-threshold-based fever alarms in their thermometers to inform the user of body temperature that is not normal.Nonetheless, more recently several publications and organizations have challenged this fixed threshold between normal temperature and fever regardless of age, specifically within the first 3 years after birth. Several studies trying to correlate body temperature to illness and infection have concluded that the upper threshold of normal body temperature varies with age [Herzog et al., 2011]. The National Institute for Health and Care Excellence [NICE, 2019] has suggested that children between 0-3 months with a temperature