1.
Magnusson, Marie, et al.
(författare)
Effects of pentoxifylline and its metabolites on platelet aggregation in whole blood from healthy humans
2008
Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 0014-2999 .- 1879-0712. ; 581:3, s. 290-5
Tidskriftsartikel (refereegranskat) abstract
It is known that pentoxifylline inhibits platelet aggregation in vitro, but the effects from pentoxifylline and its main metabolites: 3,7-dimetyl-1(5 hydroxyhexyl)xanthine (R-M1 and S-M1), 3,7-dimetyl -1(4-carboxybutyl)xanthine (M4), 3,7-dimetyl -1(3-carboxypropyl)xanthine (M5), on platelet aggregation in whole blood in vitro and in vivo have not been studied. We found that pentoxifylline, rac-M1, R-M1, S-M1 and M4 significantly inhibit ADP induced platelet aggregation in whole blood in vitro in a concentration-dependent manner, R-M1 being the most potent followed by rac-M1, S-M1, pentoxifylline, and M4. In this series of experiments the effects on aggregation induced ATP-release were less pronounced and were only significant after treatment with pentoxifylline, rac-M1 and R-M1, but the potency order appears to be the same. Since the metabolites are not available for use in humans, and also since each substance would be extensively metabolised in vivo, we made an attempt to estimate the relative contribution of each substance to the total effect of pentoxifylline in vivo. Previously published concentrations of pentoxifylline and these metabolites in humans, after administration of pentoxifylline, were used in combination with the potency ratios from this study. The findings from these calculations were that the main effect in vivo comes from S-M1 followed by pentoxifylline, the other metabolites contribute less than 10% each. In conclusion: in the following potency order R-M1, rac-M1, pentoxifylline, S-M1 and M4 all have significant effects on platelet aggregation in whole blood in vitro. However, it appears that the main effects in vivo are caused by S-M1 and pentoxifylline.
2.
Ghatnekar, Ola, et al.
(författare)
Direct hospital resource utilization and costs of treating patients with multiple myeloma in Southwest Sweden: a 5-year retrospective analysis.
2008
Ingår i: Clinical Therapeutics. - : Elsevier BV. - 0149-2918. ; 30:9, s. 1704-1713
Tidskriftsartikel (refereegranskat) abstract
BACKGROUND: Approximately 570 patients are diagnosed with multiple myeloma (MM) in Sweden each year. Few studies have estimated the cost of treatment for these patients. OBJECTIVE: The purpose of this study was to retrospectively investigate the direct hospital resource utilization and costs associated with the treatment of patients with MM in southwest Sweden. METHODS: Patients aged > or =18 years who initiated first-line chemotherapy in the year 2001 at hospitals in southwestern Sweden were included in this retrospective chart review. Direct hospital-based resources and their corresponding costs (year-2006 euros) for each patient were calculated until the patient's death, or until December 31, 2005. Costs for outpatient and terminal stage care related to MM were not included. RESULTS: Ninety-four patients were included; 20 were still alive at study completion. Mean age at diagnosis was 76 years and patients were followed for a mean of 32.7 months; 55% were males and 74% had at least 1 comorbidity. First-, second-, and third-line treatment lasted a mean of 24.3, 5.8, and 2.6 months, and included 2.8, 2.6, and 3.1 chemotherapy drugs per patient, respectively. Of the 80 patients who received first-line chemotherapy, 72 were prescribed melphalan and 55 patients received a combination of melphalan and prednisone, as recommended by Swedish treatment guidelines. The mean total cost per patient was euro88,199, or euro2770 per patient-month. Therapy-induced and comorbidity-related events constituted 42% of total costs, as much as autologous stem-cell transplantation and inpatient care together. Chemotherapy, bisphosphonate, and blood cell-enhancement drugs each amounted to only 2% of total costs, but chemotherapy drugs increased from euro29/month in first-line therapy to euro453/month in third-line therapy. CONCLUSIONS: The cost of treating Swedish patients with MM varied greatly between individuals but, overall, chemotherapy drugs constituted only a minor part of the total monthly cost (2%), whereas costs for inpatient stays and therapy-induced adverse events or comorbidity-related events accounted for 35% and42%, respectively. There was no significant differencein monthly cost between treatment lines.
3.
Lindfors, Lennart, et al.
(författare)
Nucleation and crystal growth in supersaturated solutions of a model drug
2008
Ingår i: Journal of Colloid and Interface Science. - : Elsevier BV. - 0021-9797 .- 1095-7103. ; 325:2, s. 404-413
Tidskriftsartikel (refereegranskat) abstract
The crystallization process in aqueous solutions of the drug bicalutamide and the effect of the polymer polyvinylpyrrolidone (PVP) have been studied. Results show that PVP decreased the crystallization rate significantly in a system with PVP concentrations as low as 0.01% (w/w), without changing the polymorph formed. The crystal habit was changed already at PVP concentrations as low as 0.001% (w/w). Measurements made with self-diffusion NMR indicated that the decrease in crystallization rate was not because of a reduced supersaturation due to bicalutamide binding to PVP in solution. Furthermore, in experiments designed to specifically study crystal nucleation, the same nucleation rate was found in the absence and presence of PVP. Instead, PVP adsorbes to the crystals formed in solution and by doing so, the crystal growth rate is reduced. This was confirmed in separate experiments using bicalutamide nanocrystals. By combining theories describing classical nucleation and crystal growth, with some modifications, a consistent description of several independent experiments performed in polymer-free systems was obtained. From these experiments a crystal-water interfacial tension of 22.1 mN/m was extracted. We also analyze the interfacial tension of other crystalline organic solids and find that it varies approximately as the logarithm of the solubility. This finding is discussed within the framework of the Bragg-Williams regular solution theory where we also compare with the tension of liquid alkanes.
4.
Linge, Helena M, et al.
(författare)
The human CXC chemokine granulocyte chemotactic protein 2 (GCP-2)/CXCL6 possesses membrane-disrupting properties and is antibacterial
2008
Ingår i: Antimicrobial Agents and Chemotherapy. - 1098-6596 .- 0066-4804. ; 52:7, s. 2599-2607
Tidskriftsartikel (refereegranskat) abstract
Granulocyte chemotactic protein 2 (GCP-2)/CXCL6 is a CXC chemokine expressed by macrophages and epithelial and mesenchymal cells during inflammation. Through binding and activation of its receptors (CXCR1 and CXCR2), it exerts neutrophil-activating and angiogenic activities. Here we show that GCP-2/CXCL6 itself is antibacterial. Antibacterial activity against gram-positive and gram-negative pathogenic bacteria of relevance to mucosal infections was seen at submicromolar concentrations (minimal bactericidal concentration at which 50% of strains tested were killed, 0.063 +/- 0.01 to 0.37 +/- 0.03 muM). In killed bacteria, GCP-2/CXCL6 associated with bacterial surfaces, which showed membrane disruption and leakage. A structural prediction indicated the presence of three antiparallel NH(2)-terminal beta-sheets and a short amphipathic COOH-terminal alpha-helix; the latter feature is typical of antimicrobial peptides. However, when the synthetic derivatives corresponding to the NH(2)-terminal (50 amino acids) and COOH-terminal (19 amino acids, corresponding to the putative alpha-helix) regions were compared, higher antibacterial activity was observed for the NH(2)-terminus-derived peptide, indicating that the holopeptide is necessary for full antibacterial activity. An artificial model of bacterial membranes confirmed these findings. The helical content of GCP-2/CXCL6 in the presence or absence of lipopolysaccharide or negatively charged membranes was studied by circular dichroism. As with many antibacterial peptides, membrane disruption by GCP-2/CXCL6 was dose-dependently reduced in the presence of NaCl, which, we here demonstrate, inhibited the binding of the peptide to the bacterial surface. Compared with CXC chemokines ENA-78/CXCL5 and NAP-2/CXCL7, GCP-2/CXCL6 showed a 90-fold-higher antibacterial activity. Taken together, GCP/CXCL6, in addition to its chemotactic and angiogenic properties, is likely to contribute to direct antibacterial activity during localized infection.
5.
Ringstad, Lovisa, et al.
(författare)
An electrochemical study into the interaction between complement-derived peptides and DOPC mono- and bilayers.
2008
Ingår i: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 24:1, s. 208-216
Tidskriftsartikel (refereegranskat) abstract
Electrochemical methods employing the hanging mercury drop electrode were used to study the interaction between variants of the complement-derived antimicrobial peptide CNY21 (CNYITELRRQH ARASHLGLAR) and dioleoyl phosphatidylcholine (DOPC) monolayers. Capacitance potential and impedance measurements showed that the CNY21 analogues investigated interact with DOPC monolayers coating the mercury drop. Increasing the peptide hydrophobicity by substituting the two histidine residues with leucine resulted in a deeper peptide penetration into the hydrophobic region of the DOPC monolayer, indicated by an increase in the dielectric constant of the lipid monolayer (Deltaepsilon = 2.0 after 15 min interaction). Increasing the peptide net charge from +3 to +5 by replacing the histidines by lysines, on the other hand, arrests the peptide in the lipid head group region. Reduction of electroactive ions (Tl+, Pb2+, Cd2+, and Eu3+) at the monolayer-coated electrode was employed to further characterize the types of defects induced by the peptides. All peptides studied permeabilize the monolayer to Tl+ to an appreciable extent, but this effect is more pronounced for the more hydrophobic peptide (CNY21L), which also allows penetration of larger ions and ions of higher valency. The results for the various ions indicate that charge repulsion rather than ion size is the determining factor for cation penetration through peptide-induced defects in the DOPC monolayer. The effects obtained for monolayers were compared to results obtained with bilayers from liposome leakage and circular dichroism studies for unilamellar DOPC vesicles, and in situ ellipsometry for supported DOPC bilayers. Trends in peptide-induced liposome leakage were similar to peptide effects on electrochemical impedance and permeability of electroactive ions for the monolayer system, demonstrating that formation of transmembrane pores alone does not constitute the mechanism of action for the peptides investigated. Instead, our results point to the importance of local packing defects in the lipid membrane in close proximity to the adsorbed peptide molecules.
