The effects of anesthesia and surgery on metabolic homeostasis in infancy and childhood

In order to test the hypothesis that the metabolic response to surgery in childhood varies with the age of the child and the severity of the surgery, 46 children, aged 1 month to 10 years and undergoing a variety of operations under a standard general anesthetic, were studied. Blood samples were drawn for analysis preoperatively, postoperatively, and at 6, 12, 24, and 48 hours after surgery. Severity of surgery was scored using the Oxford surgical stress scale (SSS). Surgery caused significant increases in the concentrations of lactate, pyruvate, and ketone bodies that were related to SSS, but not to age. Increases in blood glucose and insulin were also related to SSS. Total gluconeogenic substrate concentrations were markedly depressed 24 hours after surgery; this was well predicted by SSS but not by age. Older children tended to have a slightly more prolonged elevation of blood glucose and prolonged elevation of the insulin:glucose ratio postoperatively. The metabolic response of children to surgery, although different from both adults and neonates, is generally stable over a wide age range. The Oxford scale predicts the degree of metabolic displacement due to surgery and may thus prove a useful instrument in trials of anesthesia and analgesia in infants and children.     

Antibodies to the pesticide interaction sites of parathion hydrolase and cutinase

Monoclonal antibodies are able to provide information on the surface topography of biopolymers. Antibodies capable of inhibiting the activities of cutinase and parathion hydrolase have been identified in order to probe the sites of pesticide inhibition. Kinetic studies were employed to determine whether organophosphate pesticide binding was directly prevented by antibody binding. Prior binding of chlorfenvinphos and methyl paraoxon to cutinase inhibited subsequent binding by the monoclonal anti‐cutinase antibodies. The role of antibodies in probing enzyme structure is discussed.     

Indomethacin increases the effect of isosorbide dinitrate on cerebral hemodynamic in migraine patients: pathogenetic and therapeutic implications

Intracerebral vascular reactivity induced by the nitric oxide (NO) donor isosorbide dinitrate (IDN, 5 mg sublingually) is more major and longer-lasting in migraine patients who develop delayed headache in response to the drug. The headache is purportedly due to neuronally-mediated vascular mechanisms. Indomethacin inhibits prostaglandin synthesis, which is involved in NO generation. Indomethacin also decreases cerebral blood flow by constricting precapillary resistance vessels. In the present study, the hemodynamic effects of indomethacin were evaluated in migraine patients and healthy controls by means of transcranial Doppler monitoring. Indomethacin caused a significant decrease in mean flow velocity in the middle cerebral artery. This was an additional effect to the mean velocity decrease induced by IDN. The interactions between the two drugs suggest that their effects on cerebral hemodynamics (and pain) may be of relevance both in understanding the role of NO in migraine pathogenesis and in evaluating symptomatic treatments for migraine attacks.     

Catheter ablation by low energy DC shocks for successful management of atrial flutter.

OBJECTIVE--To assess the effects of low energy ablation of the substrate for atrial flutter. DESIGN--Initial retrospective analysis of patients undergoing low energy ablation of the atrioventricular node for refractory atrial flutter (group 1) was followed by a prospective assessment of low energy ablation in the posterio-inferior right atrium for the same condition (group 2). SETTING--Tertiary referral centre for management of cardiac arrhythmias. PATIENTS--Seven men (aged 50-67 years) with refractory atrial flutter. INTERVENTIONS--Multiple (3-10) low energy DC shocks with a cumulative energy of 100-245 J in the region of the atrioventricular node in group 1 and 12-15 low energy DC shocks (cumulative energy 110-235 J) guided by the anatomical landmarks of the triangle of Koch and applied directly to the atrial wall. MAIN OUTCOME MEASURE--Freedom from recurrence of atrial flutter. RESULTS--In group 1 despite initial complete atrioventricular block in three patients, atrioventricular conduction had resumed in all by one month. All four, however, were in sinus rhythm at follow up six to 13 months later. Two of the three patients in group 2 were free of atrial flutter at follow up three to four months after ablation. CONCLUSION--Ablation of the atrial flutter substrate with low energy DC shocks is feasible. Precise electrophysiological mapping is not necessary.     

Combination of ABO blood group incompatibility and glucose-6-phosphate dehydrogenase deficiency: effect on hemolysis and neonatal hyperbilirubinemia

The incidence (%) of hyperbilirubinemia (serum bilirubin ≥257 μmol/l) was similar in neonates with a combination of ABO incompatibility and glucose-6-phosphate dehydrogenase (G-6-PD) deficiency (45%), with ABO incompatibility (54%) or G-6-PD deficiency (37%), alone (ns). Carboxyhemoglobin values, corrected for inspired CO, were similarly elevated in all three groups (0.87 ± 0.32%, 0.82 ± 0.29%, 0.76 ± 0.18%, respectively, ns), but correlated with bilirubin only in those with ABO incompatibility alone. ABO-incompatible/G-6-PD-deficient neonates, compared with those with either condition alone, are not at increased risk for hemolysis or hyperbilirubinemia.     

An open trial of L-tyrosine in the treatment of attention deficit disorder, residual type

To elucidate the role of catecholamines in attention deficit disorder, the authors conducted an open 8-week trial of L-tyrosine in 12 adults with attention deficit disorder, residual type. Eight showed marked to moderate clinical response in 2 weeks; at 6 weeks these eight developed tolerance, suggesting that L-tyrosine is not useful in attention deficit disorder, residual type.     

A clinically relevant modification to existing inhaler therapy.

A modified formulation of inhaled salbutamol and a new inhaler device were studied in a group of 11 moderate-to-severe asthmatic patients. Changes in airway calibre (FEV1, Vmax30) were measured before and after inhalation of the new formulation, and compared with changes following inhalation of conventional salbutamol. A standard Rotahaler was used as a reference for the new inhaler. The study was conducted as a two-part randomized, double-blind cross-over trial. We found a significantly greater bronchodilatation of the larger airways using the modified drug in the Rotahaler. The new inhaler did not show any superiority over the Rotahaler, contrary to expectations from in vitro work. A slightly shorter model may better reflect the in vitro results. The study has implications for inhalation therapy in general.