Analgesic efficacy of rectal acetaminophen and ibuprofen alone or in combination for paediatric day-case adenoidectomy.

BACKGROUND: Acetaminophen and non-steroidal anti-inflammatory drugs have different mechanisms of action. We investigated if combining rectal acetaminophen with ibuprofen would provide better postoperative analgesia compared with either drug alone after adenoidectomy in children. METHODS: 160 children, aged 1-6 yr, undergoing day-case adenoidectomy, were randomized to receive either acetaminophen 40 mg kg(-1), ibuprofen 15 mg kg(-1), their combination, or placebo rectally immediately after anaesthetic induction. A standard anaesthetic method was used and all children received alfentanil 10 micro g kg(-1) i.v. during induction. Meperidine 5-10 mg i.v. was used for rescue analgesia for a pain score (Objective Pain Scale) over 3. Recovery times, sedation scores and the need for rescue analgesia and adverse events during the first 24 h after anaesthesia were recorded. Rescue analgesic at home was ibuprofen 10 mg kg(-1). RESULTS: Total meperidine requirements were significantly less in the groups receiving acetaminophen, ibuprofen, or their combination compared with the group receiving placebo indicating an opioid-sparing effect of 19-28% (P<0.05). Children given acetaminophen were more sedated than those given ibuprofen (P<0.05). Discharge criteria were fulfilled earlier in the ibuprofen group than in all the other groups (P<0.05). At home, less children (49%) needed rescue analgesia in the combination group compared with the other groups (74-77%) (P<0.02). CONCLUSIONS: We conclude that prophylactically administered rectal acetaminophen combined with ibuprofen does not improve analgesia after adenoidectomy in the immediate postoperative period compared with either drug alone but does decrease the need for analgesia at home. Ibuprofen results in lesser sedation and faster discharge than when acetaminophen is used.

Baculovirus-mediated large-scale expression and purification of a polyhistidine-tagged rubella virus capsid protein.

The capsid protein of rubella virus was produced in baculovirus-infected Spodoptera frugiperda insect cells, with a polyhistidine affinity tag at the carboxy terminus. The RV capsid recombinant protein was produced in a 10-liter bioreactor and purified, under nondenaturing conditions, using immobilized metal-ion affinity chromatography. Immunoblot analyses indicated that the purified recombinant protein was intact and migrated with the expected molecular weight. The final yield was 5 mg of purified protein per liter of cell culture. Surface plasmon resonance was used to investigate the antigenic potential of the histidine tagged capsid protein in an antigen-antibody interaction study. A specific interaction between the two proteins was shown. Our results suggest that this strategy should be useful in interaction studies of other virus-specific proteins and antibodies.

Synthesis of soluble rubella virus spike proteins in two lepidopteran insect cell lines: large scale production of the E1 protein.

The two envelope glycoproteins of rubella virus (RV), E1 of 58 kDa and E2 of 42-47 kDa, were individually expressed in lepidopteran Spodoptera frugiperda as well as in Trichoplusia ni insect cells using baculovirus vectors. The authentic signal sequences of E1 and E2 were replaced with the honeybee melittin signal sequence, allowing efficient entrance into the secretory pathway of the insect cell. In addition, the hydrophobic transmembrane anchors at the carboxyl termini of E1 and E2 proteins were removed to enable secretion rather than maintenance in the cellular membranes. Synthesis of the recombinant proteins in the absence and presence of tunicamycin revealed that both E1 and E2 were glycosylated with apparent molecular weights of 52 kDa and 37 kDa, respectively. Recombinant E2 appeared to be partially secreted, whereas E1 was essentially found inside the infected insect cell. The E1 protein was produced in large scale using a 10-1 bioreactor and serum-free medium (SFM). Purification of the recombinant protein product was performed from cytoplasmic extracts by ammonium sulphate precipitation followed by Concanavalin A affinity chromatography. This type of purified recombinant viral glycoproteins may be useful not only in diagnostic medicine or for immunization, but should enable studies designed to solve the structure of the virus particle.