Using the root pressure probe in the pressure clamping (PC) mode, the impact of internal unstirred layers (USLs) was quantified for young corn roots, both in experiments and in computer simulations applying the convection/diffusion model of Knipfer et al. In the experiments, water flows (J(Vr)s) during PC were analysed in great detail, showing that J(Vr)s (and the apparent root hydraulic conduc...

The relative importance of systemic volume, concentration, and pressure signals in sodium homeostasis was investigated by intravenous infusion of isotonic (IsoLoad) or hypertonic (HyperLoad) saline at a rate (1 micromol Na(+) x kg(-1) x s(-1)), similar to the rate of postprandial sodium absorption. IsoLoad decreased plasma vasopressin (-35%) and plasma ANG II (-77%) and increased renal sodium e...

Partial forced expiratory flow-volume curves obtained by the rapid chest compression technique are being widely used to assess pulmonary function in infants and young children. The aim of this study is to assess whether in this age group flow limitation is achieved with the partial forced expiratory flow-volume curve with rapid chest compression. In eight infants and young children sedated with...

An attempt was made to clarify the change of plasma human atrial natriuretic peptide (hANP) concentration before, during, and after cardiac surgery in heart failure with extracorporeal circulation. Plasma hANP concentration did not significantly decrease during total aortic cross clamping (ACC) with complete clamping of the superior and inferior vena cavae. This finding may be explained by the ...

Assessment and treatment of the VLBW infant with cardiovascular impairment requires understanding of the underlying physiology of the infant in transition. The situation is dynamic with changes occurring in systemic blood pressure, pulmonary pressures, myocardial function, and ductal shunt in the first postnatal days. New insights into the role of umbilical cord clamping in the transitional cir...

Cerebral Blood Flow Measurement as a Safeguard During Carotid Endarterectomy • Intraoperative measurement of regional cerebral blood flow (rCBF) by the Xe intracarotid injection technique was performed in 17 patients operated on for stenosis of the internal carotid artery. Mean rCBF decreased from 51 ml/100 gm x minute before endarterectomy to 30 ml/100 gm x minute when the internal carotid art...

OBJECTIVES For very preterm births, to compare alternative policies for umbilical cord clamping and immediate neonatal care. DESIGN Parallel group randomised (1:1) trial, using sealed opaque numbered envelopes. SETTING Eight UK tertiary maternity units. PARTICIPANTS 261 women expected to have a live birth before 32 weeks, and their 276 babies. INTERVENTIONS Cord clamping after at least ...

Cerebral Blood Flow Measurement as a Safeguard During Carotid Endarterectomy • Intraoperative measurement of regional cerebral blood flow (rCBF) by the Xe intracarotid injection technique was performed in 17 patients operated on for stenosis of the internal carotid artery. Mean rCBF decreased from 51 ml/100 gm x minute before endarterectomy to 30 ml/100 gm x minute when the internal carotid art...