Combination of vasostatin and cyclophosphamide in the therapy of murine melanoma tumors

Growth of tumors is strongly dependent upon supply of nutrients and oxygen by de novo formed blood vessels. Inhibiting angiogenesis suppresses growth of primary tumors as well and affects development of metastases. We demonstrate that recombinant MBP/vasostatin fusion protein inhibits proliferation of endothelial cells in vitro. The therapeutic usefulness of such intratumorally delivered recombinant protein was then assessed by investigating its ability to inhibit growth of experimental murine melanomas. In the model of B16-F10 melanoma the MBP/vasostatin construct significantly delayed tumor growth and prolonged survival of treated mice. A combination therapy involving MBP/vasostatin construct and cyclophosphamide was even more effective and led to further inhibition of the tumor growth and extended survival. We show that such combination might be useful in the clinical setting, especially to treat tumors which have already formed microvessel networks.     

The influence of axial ligands on the reduction potential of blue copper proteins

 The reduction potentials of blue copper sites vary between 180 and about 1000 mV. It has been suggested that the reason for this variation is that the proteins constrain the distance between the copper ion and its axial ligands to different values. We have tested this suggestion by performing density functional B3LYP calculations on realistic models of the blue copper proteins, including solvent effects by the polarizable continuum method. Constraining the Cu-S_Met bond length to values between 245 and 310 pm (the range encountered in crystal structures) change the reduction potential by less than 70 mV. Similarly, we have studied five typical blue copper proteins spanning the whole range of reduction potentials: stellacyanin, plastocyanin, azurin, rusticyanin, and ceruloplasmin. These studies included the methionine (or glutamine) ligand as well as the back-bone carbonyl oxygen group that is a ligand in azurin and is found at larger distances in the other proteins. The active-site models of these proteins show a variation in the reduction potential of about 140 mV, i.e., only a minor part of the range observed experimentally (800 mV). Consequently, we can conclude that the axial ligands have a small influence on the reduction potentials of the blue copper proteins. Instead, the large variation in the reduction potentials seems to arise mainly from variations in the solvent accessibility of the copper site and in the orientation of protein dipoles around the copper site. Received: 7 April 1999 / Accepted: 26 July 1999     

The Dark at the Bottom of the Stairs: Performance and Participation of Hospitalized Older People

Like all social actors, older people draw on cultural meanings to perform identity. However, when advanced aging brings loss of status as full persons, particularly when it is associated with sickness and dependency, older people can be deemed unsuitable for active medical treatment and care. In addition, loss of status may make it difficult for older people to influence how they and their needs and wants are identified, and how their future life (or death) is conceived. This article discusses how some older people who are admitted to hospital as acute medical emergencies participate in staff's discursive practices to establish a positive clinical identity. By lying low and effacing their distinctiveness as individuals and as social beings, some older people are able to maintain their inclusion in positive medical categories. The article argues that older people are committed to their inclusion in the medical domain because their association with positive medical categories helps them keep at bay the inchoate, the dark at the bottom of the stairs.     

Detection of Helicobacter in the liver of patients with chronic cholestatic liver diseases.

Helicobacter species were identified in human liver tissues by PCR. Biopsies were obtained from patients with primary sclerosing cholangitis, primary biliary cirrhosis and noncholestatic liver cirrhosis. One set of Helicobacter genus-specific primers and two different primer sets for Helicobacter pylori were used in the PCR-assays. Using Helicobacter genus-specific primers 80% (8/10) of patients with primary sclerosing cholangitis and 90% (9/10) of patients with primary biliary cirrhosis were positive. Seven of these 17 samples were positive using two different primers for H. pylori and Southern blot hybridization. Among the non-cholestatic liver cirrhosis controls, only one sample was positive in the Helicobacter genus-specific PCR-assay. Significantly higher values of alkaline phosphatases and prothrombin complex was found for the patients positive for Helicobacter genus. In conclusion, gene sequences of Helicobacter species and H. pylori were detected in human liver tissue using PCR and DNA hybridization in patients with a cholestatic liver disease, but rarely in noncholestatic liver cirrhosis.     

Presence of CpG DNA and the local cytokine milieu determine the efficacy of suppressive DNA vaccination in experimental autoimmune encephalomyelitis.

We here study the adjuvant properties of immunostimulatory DNA sequences (ISS) and coinjected cytokine-coding cDNA in suppressive vaccination with DNA encoding an autoantigenic peptide, myelin basic protein peptide 68-85, against Lewis rat experimental autoimmune encephalomyelitis (EAE). EAE is an autoaggressive, T1-mediated disease of the CNS. ISS are unmethylated CpG motifs found in bacterial DNA, which can induce production of type 1 cytokines in vertebrates through the innate immune system. Because ISS in the plasmid backbone are necessary for efficient DNA vaccination, we studied the effect of one such ISS, the 5'-AACGTT-3' motif, in our system. Treatment with a DNA vaccine encoding myelin basic protein peptide 68-85 and containing three ISS of 5'-AACGTT-3' sequence suppressed clinical signs of EAE, while a corresponding DNA vaccine without such ISS had no effect. We further observed reduced proliferative T cell responses in rats treated with the ISS-containing DNA vaccine, compared with controls. We also studied the possible impact of coinjection of plasmid DNA encoding rat cytokines IL-4, IL-10, GM-CSF, and TNF-alpha with the ISS-containing DNA vaccine. Coinjection of IL-4-, IL-10-, or TNF-alpha-coding cDNA inhibited the suppressive effect of the DNA vaccine on EAE, whereas GM-CSF-coding cDNA had no effect. Coinjection of cytokine-coding cDNA with the ISS-deficient DNA vaccine failed to alter clinical signs of EAE. We conclude that the presence of ISS and induction of a local T1 cytokine milieu is decisive for specific protective DNA vaccination in EAE.     

Pseudomonas syringae effector HopZ3 suppresses the bacterial AvrPto1–tomato PTO immune complex via acetylation

The plant pathogen Pseudomonas syringae secretes multiple effectors that modulate plant defenses. Some effectors trigger defenses due to specific recognition by plant immune complexes, whereas others can suppress the resulting immune responses. The HopZ3 effector of P. syringae pv. syringae B728a (PsyB728a) is an acetyltransferase that modifies not only components of plant immune complexes, but also the Psy effectors that activate these complexes. In Arabidopsis, HopZ3 acetylates the host RPM1 complex and the Psy effectors AvrRpm1 and AvrB3. This study focuses on the role of HopZ3 during tomato infection. In Psy-resistant tomato, the main immune complex includes PRF and PTO, a RIPK-family kinase that recognizes the AvrPto effector. HopZ3 acts as a virulence factor on tomato by suppressing AvrPto1_Psy-triggered immunity. HopZ3 acetylates AvrPto1_Psy and the host proteins PTO, SlRIPK and SlRIN4s. Biochemical reconstruction and site-directed mutagenesis experiments suggest that acetylation acts in multiple ways to suppress immune signaling in tomato. First, acetylation disrupts the critical AvrPto1_Psy-PTO interaction needed to initiate the immune response. Unmodified residues at the binding interface of both proteins and at other residues needed for binding are acetylated. Second, acetylation occurs at residues important for AvrPto1_Psy function but not for binding to PTO. Finally, acetylation reduces specific phosphorylations needed for promoting the immune-inducing activity of HopZ3’s targets such as AvrPto1_Psy and PTO. In some cases, acetylation competes with phosphorylation. HopZ3-mediated acetylation suppresses the kinase activity of SlRIPK and the phosphorylation of its SlRIN4 substrate previously implicated in PTO-signaling. Thus, HopZ3 disrupts the functions of multiple immune components and the effectors that trigger them, leading to increased susceptibility to infection. Finally, mass spectrometry used to map specific acetylated residues confirmed HopZ3’s unusual capacity to modify histidine in addition to serine, threonine and lysine residues.