Transcutaneous CO2 tension effects of clonidine in paediatric caudal analgesia

In adults, clonidine when added to bupivacaine, results in no detectable respiratory depressant effect except when carbon dioxide challenge is performed. However, to date no investigations have quantified this in children. Twenty-four children (nine months to seven years) were randomized in a double-blind study into two groups. After induction, a caudal block was performed with 1 ml·kg^?1 0.25% bupivacaine. Clonidine 1 μg·kg^?1 was added in the clonidine group, and 1 ml normal saline in the placebo group. Patients were monitored in the recovery room for three h from arrival to discharge with continuous pulse oximetry, respiratory rate, a trancutaneous CO₂ tension (tcPCO₂) every 15 min, and a four point sedation score every 30 min. Mean tcPCO₂ and respiratory rate values were not different between the two groups. Apnoea and desaturation less than 97% were not observed. The sedation score decreased with time in both groups, and the score time interval was significantly higher in the clonidine group (P<0.05). All the patients left the recovery room with a sedation score of 1, excepting four in the clonidine group with a sedation score of 2. Clonidine 1 μg·kg^?1 with 0.25% bupivacaine mixture in caudal analgesia in children did not induce an increase in tcPCO₂ despite prolonged sedation.     

Role of acetylation and charge in antimicrobial peptides based on human β‐defensin‐3

Cationic antimicrobial peptides are an evolutionarily ancient and essential element of innate immunity in higher organisms. The precise mechanism by which these peptides exert their antimicrobial activity on bacteria is not well understood. Decapeptides based on the C‐terminus of human β‐defensin‐3 were designed and evaluated to study the role of charge in defining the antimicrobial activity and selectivity of these peptides against Escherichia coli. Acetylated derivatives of these peptides were prepared in order to further evaluate how positively charged primary amines contribute to potency in these small antimicrobial peptides. These peptides enabled us to explore the relationship between net charge, charge distribution and antimicrobial activity. While the results indicate that net charge is a major factor in antimicrobial activity in these peptides, the actual relationship between charge and potency appears to be more complex.     

Total and unbound Cortisol-, progesterone-, oestrone- and transcortin-binding activities in sera from patients with myocardial infarction: evidence for differential responses of good and bad prognostic cases

Day-of-admission sera from myocardial infarction patients (MI) and patients with cardiopathies other than MI (non-MI) were analysed for total and unbound cortisol (F), progesterone (P4), oestrone (E1), and corticosteroid binding activities (CBG). The MI who survived (n = 28) showed high increases of F, P4 and E1 compared to healthy controls. By contrast, the MI who died within 10 days of admission (n = 6) had unchanged F and less increased P4 and E1 than survivors. The non-MI (n = 6) had higher F and E1 than controls but normal P4. The unbound steroids were increased in all patients: however, the MI who died showed much smaller rises than survivors (P less than 0.001 for unbound F and E1 increases in survivors vs. deceased). The CBG activity was in all MI lower than in normals (P less than 0.001) but unchanged in non-MI. These results are discussed in terms of the potential significance of unbound plasma steroids as predictors of MI severity.