The dose-response relationship for clonidine added to a postoperative continuous epidural infusion of ropivacaine in children.

Epidurally administered clonidine enhances the quality and duration of postoperative analgesia when it is used as an adjunct to local anesthetics in children. We investigated the dose-response relationship for epidural clonidine when added to a continuous postoperative epidural infusion of ropivacaine. By use of an observer-blinded design, 55 pediatric patients (1-4 yr old) were randomly given a postoperative epidural infusion of plain ropivacaine 0.1% 0.2 mg. kg(-1). h(-1) (Group R), ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.04 microg. kg(-1). h(-1) (Group RC1), ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.08 microg. kg(-1). h(-1) (Group RC2), or ropivacaine 0.08% 0.16 mg. kg(-1). h(-1) plus clonidine 0.12 microg. kg(-1). h(-1) (Group RC3). A clear dose-response relationship could be identified for a continuous infusion of epidural clonidine, with clonidine dosages in the 0.08-0.12 microg. kg(-1). h(-1) range providing improved postoperative analgesia (reduced Children's Hospital of Eastern Ontario pain score, increased time to first supplemental analgesic demand, and a reduced total number of doses of supplemental analgesics during the first 48 h after surgery). Analgesia was improved without any signs of increased sedation or other side effects. The adjunct use of epidural clonidine in the dosage range of 0.08-0.12 microg. kg(-1). h(-1) appears effective and safe for use in children. Implications: The addition of clonidine (0.08-0.12 microg.kg(-1).h(-1))to a continuous epidural infusion of ropivacaine was found to improve postoperative pain relief in children. No clinically significant signs of sedation or other side effects were observed.     

Immunohistochemical localization of membrane and alpha-granule proteins in human megakaryocytes: application to plastic-embedded bone marrow biopsy specimens

Using a new technique for antigen localization, we have demonstrated platelet proteins in megakaryocytes in plastic-embedded biopsy specimens of normal human bone marrow. In a series of 25 specimens, megakaryocytes showed labeling with antibodies to the integral membrane glycoproteins IIIa, IIb, and the IIb-IIIa complex; granule membrane protein 140; and five alpha-granule matrix proteins: thrombospondin, factor VIII-related antigen, beta-thromboglobulin, platelet factor 4, and fibrinogen. The antibodies to the membrane glycoproteins IIIa, IIb, and IIb-IIIa produced diffuse cytoplasmic staining and heavier staining on the plasma membrane, whereas the antibodies to the alpha-granule matrix proteins produced a distinct granular staining within the cytoplasm. Staining for granule membrane protein 140 was also granular in distribution. Rare mononuclear cells consistent with megakaryocyte precursors were labeled with these markers. Other enzyme histochemical and lectin-binding studies showed that the enzyme alpha-naphthyl acetate esterase, the lectin Ulex europaeus I, and the periodic-acid Schiff reaction were consistent, but not specific, markers of megakaryocytes. This immunohistochemical technique should facilitate the examination of qualitative and quantitative changes in megakaryocytes in a variety of physiologic and pathologic processes.