Elastic compression stockings one year after DVT diagnosis: Who might discontinue?

BACKGROUND: Elastic compression stockings (ECS) are uncomfortable to wear but may prevent post-thrombotic syndrome (PTS). The ability to predict PTS may help clinical decision making regarding the optimal duration of ECS after deep vein thrombosis (DVT). AIMS: Predefined endpoint analysis of the Octavia study that randomized patients who compliantly used ECS up to one year after DVT to continue or discontinue ECS treatment. Primary aim was to identify predictors of PTS. METHODS: Patient characteristics were collected and ultrasonography was performed to assess reflux, residual thrombosis and persistent thrombus load 12 months after DVT. Multivariable analyses were performed to identify factors related to PTS. RESULTS: Thrombus score ≥ 3, BMI ≥ 26, duration of symptoms before DVT diagnosis ≥ 8 days and a Villalta score of 2-4 points were statistically significant predictors of PTS. The predictive value for PTS for the assessed variables was not different between the 2 treatment groups. In the stop ECS group, 3.2% (95%CI 0.08-18) of patients without any predictors for PTS were diagnosed with mild PTS during follow-up, and none with severe PTS, for a sensitivity of 98% (95% CI 89-100), a specificity of 14% (95% CI 10-20), a positive predictive value of 20% (95% CI 19-22), and a negative predictive value of 97% (95% CI 81-100). CONCLUSION: We identified 4 predictors of PTS occurring in the 2nd year after DVT. Our findings may be used to decide on whether to continue ECS treatment for an additional year, after one year of compliant ECS use, keeping in mind that patients with none of the predictors will have the lowest PTS incidence.

One versus two years of elastic compression stockings for prevention of post-thrombotic syndrome (OCTAVIA study): randomised controlled trial.

OBJECTIVE:  To study whether stopping elastic compression stockings (ECS) after 12 months is non-inferior to continuing them for 24 months after proximal deep venous thrombosis. DESIGN:  Multicentre single blind non-inferiority randomised controlled trial. SETTING:  Outpatient clinics in eight teaching hospitals in the Netherlands, including one university medical centre. PARTICIPANTS:  Patients compliant with compression therapy for 12 months after symptomatic, ultrasound proven proximal deep venous thrombosis of the leg. INTERVENTIONS:  Continuation or cessation of ECS 12 months after deep venous thrombosis. MAIN OUTCOME MEASURES:  The primary outcome was the incidence of post-thrombotic syndrome 24 months after diagnosis of deep venous thrombosis, as assessed by the standardised Villalta scale in an intention to treat analysis. The predefined non-inferiority margin was 10%. The main secondary outcome was quality of life (VEINES-QOL/Sym). RESULTS:  518 patients compliant with ECS and free of post-thrombotic syndrome were randomised one year after diagnosis of deep venous thrombosis to stop or continue ECS therapy for another year. In the stop-ECS group, 51 of 256 patients developed post-thrombotic syndrome, with an incidence of 19.9% (95% confidence interval 16% to 24%). In the continue-ECS group, 34 of 262 patients developed post-thrombotic syndrome (incidence 13.0%, 9.9% to 17%), of whom 85% used ECS six or seven days a week during the study period, for an absolute difference of 6.9% (95% confidence interval upper limit 12.3%). Because the upper limit of the 95% confidence interval exceeds the predefined margin of 10%, non-inferiority was not reached. The number needed to treat to prevent one case of post-thrombotic syndrome by continuing ECS was 14 (95% confidence interval lower limit 8). Quality of life did not differ between the two groups. CONCLUSION:  Stopping ECS after one year in compliant patients with proximal deep venous thrombosis seemed not to be non-inferior to continuing ECS therapy for two years in this non-inferiority trial. TRIAL REGISTRATION:  Netherlands Trial Register NTR1442.

CHO expression of a novel human recombinant IgG1 anti-RhD antibody isolated by phage display.

Replacement of the hyperimmune anti-Rhesus (Rh) D immunoglobulin, currently used to prevent haemolytic disease of the newborn, by fully recombinant human anti-RhD antibodies would solve the current logistic problems associated with supply and demand. The combination of phage display repertoire cloning with precise selection procedures enables isolation of specific genes that can then be inserted into mammalian expression systems allowing production of large quantities of recombinant human proteins. With the aim of selecting high-affinity anti-RhD antibodies, two human Fab libraries were constructed from a hyperimmune donor. Use of a new phage panning procedure involving bromelin-treated red blood cells enabled the isolation of two high-affinity Fab-expressing phage clones. LD-6-3 and LD-6-33, specific for RhD. These showed a novel reaction pattern by recognizing the D variants D(III), D(IVa), D(IVb), D(Va), D(VI) types I and II. D(VII), Rh33 and DFR. Full-length immunoglobulin molecules were constructed by cloning the variable regions into expression vectors containing genomic DNA encoding the immunoglobulin constant regions. We describe the first, stable, suspension growth-adapted Chinese hamster ovary (CHO) cell line producing a high affinity recombinant human IgG1 anti-RhD antibody adapted to pilot-scale production. Evaluation of the Fc region of this recombinant antibody by either chemiluminescence or antibody-dependent cell cytotoxicity (ADCC) assays demonstrated macrophage activation and lysis of red blood cells by human lymphocytes. A consistent source of recombinant human anti-RhD immunoglobulin produced by CHO cells is expected to meet the stringent safety and regulatory requirements for prophylactic application.

Identification of Man alpha1-3Man alpha1-2Man and Man-linked phosphate on O-mannosylated recombinant leech-derived tryptase inhibitor produced by Saccharomyces cerevisiae and determination of the solution conformation of the mannosylated polypeptide.

The production of recombinant leech-derived tryptase inhibitor (rLDTI) by two different strains of Saccharomyces cerevisiae resulted in the secretion of non-glycosylated and glycosylated rLTDI. Monosaccharide analysis and a-mannosidase treatment demonstrated that glycosylated rLDTI was exclusively alpha-mannosylated. A trypsin digest of reduced and S-carboxymethylated glycosylated rLDTI was separated on a reverse-phase HPLC column. Glycopeptides identified by a combination of matrix-assisted laser desorption mass spectrometry, amino acid sequence analysis, and monosaccharide analysis revealed the presence of different glycoforms. It was found that Ser24, Ser33 and Ser36 were partially glycosylated with a single mannose residue, whereas Thr42 in glycosylated rLDTI from both strains was fully occupied with manno-oligosaccharides with a degree of polymerization ranging over 1-3 and 1-13 depending on the yeast strain. In phosphorylated rLDTI a single phosphate group was predominantly located at the innermost Man residue of units of mannobiose, mannotriose, mannotetraose and mannopentaose at Thr42. Oligosaccharides released by alkaline treatment were reduced by sodium borohydride and separated by high-pH anion-exchange chromatography on a CarboPac MA1 column, and analyzed by one- and two-dimensional 1H-NMR spectroscopy. Besides the major oligosaccharide Man alpha1-2Man-ol, the (for yeast protein O-glycosylation) unusual Man alpha1-3Man alpha1-2Man-ol was determined. The solution conformation of glycosylated rLDTI was investigated by two-dimensional NMR spectroscopy. Structure calculations by means of distance geometry showed that glycosylated rLDTI is compactly folded and contained small secondary structure elements. Analysis of the chemical shifts showed that amino acids Val32-Ser33, Ser36-Ser39 and Thr42 were affected by the O-mannosylation. In addition, changes in chemical shift were observed within the beta-hairpin peptide regions Val13-Ser16 and Gly18-Tyr21 attributed to direct interactions of the mannose residue at Ser36. Furthermore, the protein-linked oligosaccharides were spatially grouped in a position opposite of the canonical binding loop.

Glyceraldehyde-3-phosphate dehydrogenase, the putative target of the antiapoptotic compounds CGP 3466 and R-(-)-deprenyl.

R-(-)-Deprenyl (Selegiline) represents one of the drugs currently used for the treatment of Parkinson's disease. This compound was shown to protect neurons or glias from programmed cell death in a variety of models. The mechanism of action of neuroprotection as well as inhibition of apoptosis remains elusive. CGP 3466 is a structurally related analog of R-(-)-deprenyl that exhibits virtually no monoamine oxidase type B inhibiting activity but is neuroprotective in the picomolar concentration range. We showed specific binding of CGP 3466 to glyceraldehyde-3-phosphate dehydrogenase by affinity binding, by affinity labeling, and by means of BIAcore(R) technology. Apoptosis assays based on the human neuroblastoma cell line PAJU established the importance of this interaction for mediating drug-induced inhibition of programmed cell death.

Synthesis of tools for target identification of the anti-apoptotic compound CGP 3466; Part I.

Immobilized compounds for BIAcore studies and affinity precipitation as well as a fluorescent-labeled compound were prepared in order to identify the molecular target of the anti-apoptotic, neurorescuing compound CGP 3466 (N-methyl-N-propargyl-10-aminomethyl-dibenzo[b,f]oxepin).

Liquid-chromatographic study of fluorescent materials in uremic fluids.

Using reversed-phase "high-performance" liquid chromatography with fluorescence detection, we separated and identified some naturally fluorescent compounds in uremic serum and hemodialysate from patients with chronic renal disease. Several of the naturally fluorescent compounds were identified as indole derivatives by co-chromatography with authentic standards. In one specific case, the identity was confirmed by an enzymic peak-shift method. Compounds identified included indican, kynurenic acid, tryptophan, and 5-hydroxy-indole-3-acetic acid. Comparison of normal and uremic serum showed that the fluorescent materials are present in significantly greater concentrations in samples from uremic patients.