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Biomedical subjects

A Petros

Publications and source records attributed to A Petros.

30 records · Page 2Linked to original sources
PubMed1999

The use of the laryngeal mask airway for inter-hospital transport of infants with type 3 laryngotracheo-oesophageal clefts.

Type 3 laryngotracheo-oesophageal clefts are rare congenital anomalies with a high mortality. In the past, transport of such infants to tertiary centres for surgical correction has proved extremely difficult, with the child's ventilatory status often deteriorating to such an extent that ultimate surgical intervention has not proved possible. We describe two cases of successful inter-hospital transfer of infants with type 3 laryngotracheo-oesophageal clefts using the laryngeal mask airway.

Emergency Service, Hospital↗
PubMed1999

Antioxidant protection against iron toxicity: plasma changes during cardiopulmonary bypass in neonates, infants, and children.

Cardiopulmonary bypass surgery is associated with the release of low molecular mass iron, which increases the saturation of plasma transferrin to over 50% in all adult patients treated. In a significant minority, however plasma transferrin becomes 100% iron saturated and non-transferrin bound iron can be detected in the plasma. An iron-saturated transferrin is also a common physiological finding in normal term and pre-term infants at a time when their plasma antioxidants, which protect against iron toxicity and radical scavenging, are profoundly different from those seen in adults. This study was conducted to assess the extent to which antioxidants, which protect against iron toxicity, are altered in neonates, infants, and children undergoing cardiopulmonary bypass surgery.

Antioxidants↗
PubMed1995

The pharmacokinetics of alfentanil after normothermic and hypothermic cardiopulmonary bypass.

The pharmacokinetics of alfentanil were studied after two different methods of cardiopulmonary bypass (CPB) which used either a normothermic technique or a hypothermic technique with body temperatures below 30 degrees C. A group of surgical patients who did not undergo CPB were also studied. All patients (n = 36) received alfentanil 50 micrograms/kg as a rapid infusion over 10 min and plasma levels were measured for the following 8 h. The volume of distribution in steady state (Vdss) and the volume of central compartment (Vc) were significantly greater in the CPB groups (P = 0.009 and P = 0.04), compared to the nonbypass group. However, the elimination half-life of alfentanil (t1/2 beta) (mean, 95% confidence interval) did not differ significantly between the normothermic (134 min, range 104-172), hypothermic (143 min, range 111-184), and nonbypass (111 min, range 86-142) groups. Between the normothermic and hypothermic CPB groups no significant differences in Vdss, rate of clearance (Cl), or t1/2 beta were found. The pharmacokinetics of alfentanil showed fewer changes after CPB in this study than have been reported previously. Furthermore, different temperature management protocols during CPB did not influence alfentanil elimination.

Aged↗
PubMed1994

Effects of a nitric oxide synthase inhibitor in humans with septic shock.

OBJECTIVE: Studies in animals have indicated that increased production of nitric oxide from an inducible isoform of nitric oxide synthase contributes to the pathophysiology of endotoxic and cytokine induced shock. The aim of this study was to determine the role of nitric oxide in septic shock in humans. METHODS: The study was a randomised, double blind, placebo controlled investigation of the effects of the nitric oxide synthase inhibitor NG monomethyl-L-arginine (L-NMMA) in 12 patients with severe sepsis associated with hypotension. Measurements of haemodynamic, haematological, and biochemical variables were made. RESULTS: L-NMMA (0.3 and 1 mg.kg-1) produced a dose dependent increase in mean arterial pressure, systemic vascular resistance, pulmonary vascular resistance, central venous pressure, and pulmonary artery occlusion pressure, and a decrease in cardiac output and heart rate. In response to the highest dose of L-NMMA systemic vascular resistance increased from 547(SEM 92) to 889(143) dyne.s.cm-5, mean arterial blood pressure increased from 80.9(2.9) to 100.5(6.1) mm Hg, and cardiac output decreased from 11.2(2.1) to 8.9(1.9) litres.min-1. Continuous infusion of L-NMMA (1 mg.kg-1 x h-1) produced sustained haemodynamic changes. Platelet numbers decreased during the course of the study in both the L-NMMA and the placebo group and did not differ significantly between the groups. CONCLUSIONS: Low doses of L-NMMA cause a widespread increase in vascular tone and raise blood pressure in patients with septic shock. Overproduction of nitric oxide appears to be an important mechanism in septic shock in patients, and inhibition of nitric oxide synthesis might provide a novel therapeutic approach to this condition. However, L-NMMA produced a fall in cardiac output and it is possible that this would worsen tissue perfusion. Larger studies examining the effects of L-NMMA on mortality and morbidity are now required.

Adult↗
PubMed1991

Characterization of a posttranslational fucosylation in the growth factor domain of urinary plasminogen activator.

A posttranslational modification site in natural and recombinant urinary-type plasminogen activators (urokinases; EC 3.4.21.31) has been localized to Thr-18, in the growth factor domain of the molecule. This is the region of urinary plasminogen activator responsible for its specific receptor binding. An unusual carbohydrate-protein linkage, a single monosaccharide, fucose, covalently attached directly to threonine in the peptide, is described here. The glycan moiety and the site of modification have been identified with mass spectrometry and confirmed by carbohydrate composition analysis, Edman degradation, and one- and two-dimensional NMR studies. This type of modification is normally not detected without mass spectrometry because the fucose-threonine bond is hydrolyzed under standard acidic conditions of the amino acid analysis and Edman sequencing. This modification may be widely found in other proteins.

Amino Acid Sequence↗
PubMedDate not supplied

Effect of nitric oxide synthase inhibitors on hypotension in patients with septic shock.

Hypotension during septic shock, which may reflect increased synthesis of the potent vasodilator nitric oxide (NO), is often refractory to vasoconstrictors. We describe the effects of NO synthase inhibition in two patients with life-threatening septic shock in whom conventional therapy had failed to restore blood pressure. NG-monomethyl-L-arginine (L-NMMA) caused dose-dependent increases in blood pressure and systemic vascular resistance in both patients, and a similar effect was observed in the second patient after treatment with NG-nitro-L-arginine methyl ester (L-NAME). These findings indicate that NO synthase induction contributes to the pathogenesis of septic shock, and that inhibition of NO synthase may represent a novel therapeutic option.

Amino Acid Oxidoreductases↗