Analgesic efficacy and tolerability of intravenous morphine versus combined intravenous morphine and oxycodone in a 2-center, randomized, double-blind, pilot trial of patients with moderate to severe pain after total hip replacement.

BACKGROUND: Results from studies with a combination of oral morphine and oxycodone in postsurgical patients demonstrate significant analgesia and a tolerability profile comparable to other pain medications at morphine-equivalent doses. However, an intravenous (IV) combination has not previously been studied. OBJECTIVE: This study evaluated the efficacy and tolerability of IV morphine versus a combination of IV morphine and IV oxycodone in a 1:1 ratio. METHODS: This was a 2-center, randomized, double-blind, active-controlled pilot trial of 40 patients who had undergone total hip replacement. After surgery, when pain levels reached ≥4 (on the 11-point Numerical Pain Rating Scale), patients were randomized to 1 of 2 treatment groups. In part 1 of the study, patients were dosed every 5 minutes for the first 65 minutes (up to 13 doses) with study drug, provided that vital signs criteria were met. After an initial loading dose of either morphine 1.5 mg coadministered with oxycodone 1.5 mg or morphine 3 mg alone, patients received IV morphine 1.5 mg or IV morphine 0.75 mg/IV oxycodone 0.75 mg every 5 minutes. If patients achieved a pain score of 2 or experienced intolerable adverse events to drug when stable, they were permitted to enter part 2. In part 2, patients received blinded study medication (IV morphine plus IV oxycodone [0.5 mg/0.5 mg] or 1 mg IV morphine alone) via patient-controlled analgesia (PCA) for 47 hours. RESULTS: At baseline, treatment groups were comparable except for a higher proportion of females in the IV morphine group. Baseline pain intensity averaged 7 on the Numerical Pain Rating Scale of 0 to 10. One patient in the morphine group and 2 patients in the morphine/oxycodone group discontinued the study. The sum of the pain intensity differences from baseline to 65 minutes during the dose-titration phase was 1.8 for morphine alone versus 2.7 for morphine/oxycodone (P = 0.12); these values occurred at the same median number of doses (12) for each group. In part 2 (PCA dosing) of the study, similar levels of analgesia were achieved. During the study, 24% of the IV morphine/oxycodone group and 37% of the IV morphine group experienced nausea, and 10% of the IV morphine/oxycodone group and 16% of the IV morphine group had emesis. Two patients in the IV morphine/oxycodone group and 4 in the IV morphine alone group experienced oxygen desaturation. CONCLUSIONS: The combination of IV morphine and oxycodone provided pain relief with an acceptable tolerability profile in these patients experiencing moderate to severe postoperative pain. However, as an explorative pilot study, the power was not adequate to demonstrate statistical significance for differences between IV morphine/oxycodone and IV morphine alone. European Clinical Trials Data Base registration code: EudraCT-No. 2008-008527-14.

Inhibition of T-cell proliferation by Helicobacter pylori gamma-glutamyl transpeptidase.

BACKGROUND & AIMS: Helicobacter pylori colonizes the human gastric mucosa of >50% of the world's population. Most of the patients have no overt clinical symptoms. However, the infection is invariably associated with the development of active chronic gastritis, leading in some cases to the development of peptic ulcer disease, distal gastric adenocarcinoma, and mucosa-associated lymphoid tissue lymphoma. In contrast to most other pathogens, infection with H pylori persists lifelong, but reasons for the persistence remain obscure. CD4-positive T cells are crucial for bacterial elimination but are inhibited by H pylori. We aimed to identify the factor responsible for suppression of T-cell response and characterize this inhibitory effect on a cellular and molecular level. METHODS: Using size-exclusion chromatography, sodium dodecyl sulfate/polyacrylamide gel electrophoresis, and a spectrophotometric enzyme assay, we identified the secreted gamma-glutamyl transpeptidase of H pylori (HPGGT) as the factor responsible for inhibition of T-cell proliferation. RESULTS: Mutagenesis of HPGGT in different H pylori strains completely abrogated this inhibitory effect. Recombinantly expressed HPGGT protein showed full antiproliferative activity. Site-directed mutagenesis and application of the GGT inhibitor acivicin revealed that inhibition of T cells depends on catalytic activity of HPGGT. Cell cycle analysis of human T cells indicated that HPGGT was necessary and sufficient to induce G(1) arrest. Reduced levels of c-Myc and phosphorylated c-Raf protein suggest the disruption of Ras-dependent signaling by HPGGT. CONCLUSIONS: GGT is a novel immunosuppressive factor of H pylori inhibiting T-cell proliferation by induction of a cell cycle arrest in the G(1) phase.

VacA-associated inhibition of T-cell function: reviewed and reconsidered.

Chronic Helicobacter pylori infection is characterized by dense infiltration of the mucosa with neutrophilic granulocytes, lymphocytes, and monocytes/macrophages. Among these different cell types, T-lymphocytes are the most intriguing and crucial cells for the elimination of the bacteria. Previous studies have elucidated possible mechanisms on how bacteria could interfere with the human immune response and claimed that especially the secreted vacuolating toxin VacA may be responsible for the chronic persistence of the bacteria. Some of these results have to be interpreted with caution and may just describe in vitro phenomena; others may reveal promising facts.

Multigene family encoding 3',5'-cyclic-GMP-dependent protein kinases in Paramecium tetraurelia cells.

In the ciliate Paramecium tetraurelia, 3',5'-cyclic GMP (cGMP) is one of the second messengers involved in several signal transduction pathways. The enzymes for its production and degradation are well established for these cells, whereas less is known about the potential effector proteins. On the basis of a current Paramecium genome project, we have identified a multigene family with at least 35 members, all of which encode cGMP-dependent protein kinases (PKGs). They can be classified into 16 subfamilies with several members each. Two of the genes, PKG1-1 and PKG2-1, were analyzed in more detail after molecular cloning. They encode monomeric enzymes of 770 and 819 amino acids, respectively, whose overall domain organization resembles that in higher eukaryotes. The enzymes contain a regulatory domain of two tandem cyclic nucleotide-binding sites flanked by an amino-terminal region for intracellular localization and a catalytic domain with highly conserved regions for ATP binding and catalysis. However, some Paramecium PKGs show a different structure. In Western blots, PKGs are detected both as cytosolic and as structure-bound forms. Immunofluorescence labeling shows enrichment in the cell cortex, notably around the dense-core secretory vesicles (trichocysts), as well as in cilia. Immunogold electron microscopy analysis reveals consistent labeling of ciliary membranes, of the membrane complex composed of cell membrane and cortical Ca2+ stores, and of regions adjacent to ciliary basal bodies, trichocysts, and trafficking vesicles. Since PKGs (re)phosphorylate the exocytosis-sensitive phosphoprotein pp63/pf upon stimulation, the role of PKGs during stimulated exocytosis is discussed, in addition to a role in ciliary beat regulation.

Molecular identification of a calcium-inhibited catalytic subunit of casein kinase type 2 from Paramecium tetraurelia.

We have previously described the occurrence in Paramecium of a casein kinase (CK) activity (EC 2.7.1.37) with some unusual properties, including inhibition by Ca(2+) (R. Kissmehl, T. Treptau, K. Hauser, and H. Plattner, FEBS Lett. 402:227-235, 1995). We now have cloned four genes, PtCK2alpha1 to PtCK2alpha4, all of which encode the catalytic alpha subunit of type 2 CK (CK2) with calculated molecular masses ranging from 38.9 to 39.4 kDa and pI values ranging from 8.8 to 9.0. They can be classified into two groups, which differ from each other by 28% on the nucleotide level and by 18% on the derived amino acid level. One of them, PtCK2alpha3, has been expressed in Escherichia coli and characterized in vitro. As we also have observed with the isolated CK, the recombinant protein preferentially phosphorylates casein but also phosphorylates some Paramecium-specific substrates, including the exocytosis-sensitive phosphoprotein pp63/parafusin. Characteristically, Ca(2+) inhibits the phosphorylation at elevated concentrations occurring during stimulation of a cell. Reconstitution with a recombinant form of the regulatory subunit from Xenopus laevis, XlCK2beta, confirms Ca(2+) sensitivity also under conditions of autophosphorylation. This is unusual for CK2 but correlates with the presence of two EF-hand calcium-binding motifs, one of which is located in the N-terminal segment essential for constitutive activity, as well as with an aberrant composition of normally basic domains recognizing acidic substrate domains. Immunogold localization reveals a considerable enrichment in the outermost cell cortex layers, excluding cilia. We discuss a potential role of this Ca(2+)-inhibited PtCK2alpha species in a late step of signal transduction.