Long-term effects of joint bleeding before starting prophylaxis in severe haemophilia.

INTRODUCTION: Early initiation of prophylaxis in severe haemophilia is critical for effective prevention of arthropathy. However, the optimum time for starting prophylaxis has not been established yet. AIM: This study assessed long-term effects of age at starting prophylaxis and joint bleeding before prophylaxis on haemophilic arthropathy. METHODS: In patients with severe haemophilia (FVIII/IX <0.01 IU mL-1 ), born between 1965 and 2000, haemophilic arthropathy was evaluated on X-rays. Patient groups were compared by multivariable regression analysis, adjusted for bleeding phenotype and lifetime intensity of prophylaxis. RESULTS: One hundred and twenty-four patients were evaluated at a median age of 22 years. When comparing patients according to age at starting prophylaxis, starting before age 6 years was significantly better than starting later (P < 0.01), but no additional benefit of starting before age 3 years was demonstrated. The number of joint bleeds before prophylaxis had a stronger association with arthropathy than age at starting prophylaxis. Starting prophylaxis before the onset of joint bleeding resulted in the best long-term outcome (P ≤ 0.02); starting after one joint bleed appeared to have acceptable long-term outcome. The difference between starting after 0-1 and 2-5 joint bleeds was notable, but statistical significance was not reached (P = 0.15). CONCLUSION: Future research with more patients on early prophylaxis will have to clarify whether starting prophylaxis before joint bleeding is superior.

Evaluating outcome of prophylaxis in haemophilia: objective and self-reported instruments should be combined.

INTRODUCTION: Routine outcome assessment of prophylaxis should use validated tools, while balancing comprehensiveness and burden. Collecting overlapping information should be avoided. AIM: To assess correlations between different outcome assessment tools in haemophilia. METHODS: From an international cross-sectional study, data on objective outcome (Haemophilia Joint Health Score (HJHS 2.1, range 0-124), radiological Pettersson score) and self-reported joint bleeding, Haemophilia Activities List (HAL, range 100-0), health-related quality of life (SF-36, including five physical and five mental domain scores, range 100-0), and Utility (SF6D and EQ-5D, range 1.0-0) were extracted. Spearman's correlations were calculated: ≥0.8 very strong, 0.60-0.79 strong, 0.40-0.59 moderate. RESULTS: Ninety patients with severe haemophilia, on prophylaxis since median age 3.4 years, were evaluated at median 25.5 years (range 16.0-37.6). Objective outcome was favourable (median HJHS 2.1 6 points, Pettersson score 9 points). Self-reported outcome showed a median of 7 joint bleeds in 5 years, median HAL sum 96 points, high scores for physical domains of SF-36 (median 80-95) and high Utility values (median SF6D 0.87; EQ-5D 0.84). Physical examination (HJHS 2.1) showed strong correlation with radiological scores, moderate correlation with physical domains of the SF-36 and Utility, but no correlation with self-reported bleeding or limitations in activities (HAL). Bleeding was not associated with any other outcome parameter. The HAL was only correlated with the SF36 'Physical functioning' domain. CONCLUSION: For the evaluation of patients on early prophylaxis, information on bleeding should be complemented by objective joint assessment as well as self-reported limitations in activities and quality of life.

Using routine Haemophilia Joint Health Score for international comparisons of haemophilia outcome: standardization is needed.

INTRODUCTION: Haemophilia Joint Health Score (HJHS) is the most sensitive validated score for physical examination of joint health in haemophilia. HJHS performed at regular intervals can be used for clinical monitoring as well as for comparative outcomes research. AIM: To determine whether routinely collected HJHS could be used to compare outcome of three different prophylactic regimens in children with severe haemophilia A (primary) and which parameters caused variability in HJHS (secondary). METHODS: International retrospective observational multi-centre study comparing routine HJHS in 127 children with severe haemophilia A born from 1995 to 2009, from London, Stockholm and Utrecht centres. Patient and treatment data were collected from the European Paediatric Network for Haemophilia Management registry and patient files. The independent effects of regimens, physiotherapists, age and inhibitor status on HJHS were explored, using multivariable regression analysis. RESULTS: Prophylaxis varied across participating centres, with differences in initial frequency of infusions (1× per week vs. 3× per week), age at reaching infusions ≥3× per week, and dose kg(-1) week(-1) at HJHS assessment. Evaluation at median age of 11 years showed an illogical association of HJHS with treatment regimen: the least intensive regimen had the lowest HJHS. The HJHS increased with age and history of inhibitor, as expected (internal validity). But the comparison of prophylactic regimens was obscured by systematic differences in assessment between physiotherapists, both within and between centres. CONCLUSION: Inter-physiotherapist discrepancies in routine HJHS hamper comparison of scores between treatment regimens. For multi-centre research, additional inter-observer standardization for HJHS scoring is needed.

How to achieve full prophylaxis in young boys with severe haemophilia A: different regimens and their effect on early bleeding and venous access.

To facilitate early prophylaxis, step-up regimens starting prophylaxis with infusions 1× week(-1) were introduced. Choice of initial regimen may affect outcome. This study aims to classify initial prophylactic regimens and compare them on short-term outcome. From the 'European Paediatric Network for Haemophilia Management' (PedNet) registry, patients with severe haemophilia A without inhibitors, born 2000-2012, receiving prophylaxis were included. Treatment centres were classified according to the initial frequency of prophylactic infusions and the age at reaching infusions ≥3× week(-1) . Bleeding, and central venous access device (CVAD) use were compared at age 4 years. In 21 centres with 363 patients, three regimens were identified: (i) start prophylaxis with ≥3× week(-1) infusions before age three (full: 19% of centres, 18% of patients); (ii) start 1-2× week(-1) , increasing frequency as soon as possible (asap), reaching ≥3× week(-1) before age three (43% of centres, 36% of patients); (iii) start 1-2× week(-1) , increasing frequency according to bleeding (phenotype), reaching ≥3× week(-1) after age three (38% of centres, 46% of patients). Prophylaxis was started at median 1.2 years on the full and asap regimen vs 1.8 years on the phenotype regimen. Complete prevention of joint bleeds was most effective on the full regimen (32% full vs. 27% asap and 8% phenotype), though at the cost of using most CVADs (88% full vs. 34% asap and 22% phenotype). The three prophylaxis regimens identified had different effects on early bleeding and CVAD use. This classification provides the first step towards establishing the optimum prophylactic regimen.

Small molecule- and amino acid-induced aggregation of gold nanoparticles.

To understand which organic molecules are capable of binding to gold nanoparticles and/or inducing nanoparticle aggregation, we investigate the interaction of gold nanoparticles with small molecules and amino acids at variable pH. Dynamic Light Scattering (DLS) and ultraviolet-visible (UV-vis) spectra were measured on mixtures of colloidal gold with small molecules to track the progression of the aggregation of gold nanoparticles. We introduce the 522 to 435 nm UV-vis absorbance ratio as a sensitive method for the detection of colloidal gold aggregation, whereby we delineate the ability of thiol, amine, and carboxylic acid functional groups to bind to the surfaces of gold nanoparticles and investigate how combinations of these functional groups affect colloidal stability. We present models for mechanisms of aggregation of colloidal gold, including surface charge reduction and bridging linkers. For all molecules whose addition leads to the aggregation of gold nanoparticles, the aggregation kinetics were accelerated at acidic pH values. Colloidal gold is maintained only in the presence of anionic carboxyl groups, which are neutralized by protonation at lower pH. The overall reduced charge on the stabilizing carboxyl groups accounts for the accelerated aggregation at lower pH values.

Nanotechnologies for biomolecular detection and medical diagnostics.

Nanotechnology-based platforms for the high-throughput, multiplexed detection of proteins and nucleic acids in heretofore unattainable abundance ranges promise to bring substantial advances in molecular medicine. The emerging approaches reviewed in this article, with reference to their diagnostic potential, include nanotextured surfaces for proteomics, a two-particle sandwich assay for the biological amplification of low-concentration biomolecular signals, and silicon-based nanostructures for the transduction of molecular binding into electrical and mechanical signals, respectively.

Physicochemically modified silicon as a substrate for protein microarrays.

Reverse phase protein microarrays (RPMA) enable high throughput screening of posttranslational modifications of important signaling proteins within diseased cells. One limitation of protein-based molecular profiling is the lack of a PCR-like intrinsic amplification system for proteins. Enhancement of protein microarray sensitivities is an important goal, especially because many molecular targets within patient tissues are of low abundance. The ideal array substrate will have a high protein-binding affinity and low intrinsic signal. To date, nitrocellulose-coated glass has provided an effective substrate for protein binding in the microarray format when using chromogenic detection systems. As fluorescent systems, such as quantum dots, are explored as potential reporter agents, the intrinsic fluorescent properties of nitrocellulose-coated glass slides limit the ability to image microarrays for extended periods of time where increases in net sensitivity can be attained. Silicon, with low intrinsic autofluorescence, is being explored as a potential microarray surface. Native silicon has low binding potential. Through titrated reactive ion etching (RIE), varying surface areas have been created on silicon in order to enhance protein binding. Further, via chemical modification, reactive groups have been added to the surfaces for comparison of relative protein binding. Using this combinatorial method of surface roughening and surface coating, 3-aminopropyltriethoxysilane (APTES) and mercaptopropyltrimethoxysilane (MPTMS) treatments were shown to transform native silicon into a protein-binding substrate comparable to nitrocellulose.

Controlled-release microchips.

Efficient drug delivery remains an important challenge in medicine: continuous release of therapeutic agents over extended time periods in accordance with a predetermined temporal profile; local delivery at a constant rate to the tumour microenvironment to overcome much of the systemic toxicity and to improve antitumour efficacy; improved ease of administration, and increasing patient compliance required are some of the unmet needs of the present drug delivery technology. Microfabrication technology has enabled the development of novel controlled-release microchips with capabilities not present in the current treatment modalities. In this review, the current status and future prospects of different types of controlled-release microchips are summarised and analysed with reference to microneedle-based microchips, as well as providing an in-depth focus on microreservoir-based and nanoporous microchips.

Application of physicochemically modified silicon substrates as reverse-phase protein microarrays.

Physicochemically modified silicon substrates can provide a high quality alternative to nitrocellulose-coated glass slides for use in reverse-phase protein microarrays. Enhancement of protein microarray sensitivities is an important goal, especially because molecular targets within patient tissues exist in low abundance. The ideal array substrate has a high protein binding affinity and low intrinsic background signal. Silicon, which has low intrinsic autofluorescence, is being explored as a potential microarray surface. In a previous paper ( Nijdam , A. J. ; Cheng , M. M.-C. ; Fedele , R. ; Geho , D. H. ; Herrmann , P. ; Killian , K. ; Espina , V. ; Petricoin , E. F. ; Liotta , L. A. ; Ferrari , M. Physicochemically Modified Silicon as Substrate for Protein Microarrays . Biomaterials 2007 , 28 , 550 - 558 ), it is shown that physicochemical modification of silicon substrates increases the binding of protein to silicon to a level comparable with that of nitrocellulose. Here, we apply such substrates in a reverse-phase protein microarray setting in two model systems.

Nanoporous surfaces as harvesting agents for mass spectrometric analysis of peptides in human plasma.

Silica-based nanoporous surfaces have been developed in order to capture low molecular weight peptides from human plasma. Harvested peptides were subjected to mass spectrometric analysis by using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) as a means of detecting and assessing the bound molecules. Peptide profiles consisting of about 70 peaks in the range 800-10,000 m/z were generated. The method could allow detection of small peptides at ng/mL concentration levels, either in standard solutions or in plasma. The same molecular cutoff effect was observed for mixtures of standard proteins and peptides incubated with silicon-based nanoporous surfaces.

Selective binding and enrichment for low-molecular weight biomarker molecules in human plasma after exposure to nanoporous silica particles.

The present manuscript describes a biomarker capturing strategy based on nanoporous silica particles. The method is shown to enrich the yield of species in the low-molecular weight proteome (LMWP), allowing detection of small peptides in the low-nanomolar range. Plasma samples were exposed to the silica particles, and the captured molecular species were profiled using MALDI-TOF. Mass spectra of the silica-treated human plasma samples showed a significant enrichment in MALDI-TOF protein profiles in the LMWP. Preliminary results indicated good level of reproducibility in plasma profiles with CVs on peak heights ranging from 6.3 to 14.7%. The MALDI-TOF signature changed significantly when the characteristics of the nanoporous silica were altered. The facile sample pretreatment before MS analysis, coupled to the potential for tailoring the surface properties of silica supports, hold promise for improving the recovery of low-abundance serum biomarkers.