Genome Sequencing for Diagnosing Rare Diseases.

BACKGROUND: Genetic variants that cause rare disorders may remain elusive even after expansive testing, such as exome sequencing. The diagnostic yield of genome sequencing, particularly after a negative evaluation, remains poorly defined. METHODS: We sequenced and analyzed the genomes of families with diverse phenotypes who were suspected to have a rare monogenic disease and for whom genetic testing had not revealed a diagnosis, as well as the genomes of a replication cohort at an independent clinical center. RESULTS: We sequenced the genomes of 822 families (744 in the initial cohort and 78 in the replication cohort) and made a molecular diagnosis in 218 of 744 families (29.3%). Of the 218 families, 61 (28.0%) - 8.2% of families in the initial cohort - had variants that required genome sequencing for identification, including coding variants, intronic variants, small structural variants, copy-neutral inversions, complex rearrangements, and tandem repeat expansions. Most families in which a molecular diagnosis was made after previous nondiagnostic exome sequencing (63.5%) had variants that could be detected by reanalysis of the exome-sequence data (53.4%) or by additional analytic methods, such as copy-number variant calling, to exome-sequence data (10.8%). We obtained similar results in the replication cohort: in 33% of the families in which a molecular diagnosis was made, or 8% of the cohort, genome sequencing was required, which showed the applicability of these findings to both research and clinical environments. CONCLUSIONS: The diagnostic yield of genome sequencing in a large, diverse research cohort and in a small clinical cohort of persons who had previously undergone genetic testing was approximately 8% and included several types of pathogenic variation that had not previously been detected by means of exome sequencing or other techniques. (Funded by the National Human Genome Research Institute and others.).

Intra-individual variability in task performance after cognitive training is associated with long-term outcomes in children.

The potential benefits and mechanistic effects of working memory training (WMT) in children are the subject of much research and debate. We show that after five weeks of school-based, adaptive WMT 6-9 year-old primary school children had greater activity in prefrontal and striatal brain regions, higher task accuracy, and reduced intra-individual variability in response times compared to controls. Using a sequential sampling decision model, we demonstrate that this reduction in intra-individual variability can be explained by changes to the evidence accumulation rates and thresholds. Critically, intra-individual variability is useful in quantifying the immediate impact of cognitive training interventions, being a better predictor of academic skills and well-being 6-12 months after the end of training than task accuracy. Taken together, our results suggest that attention control is the initial mechanism that leads to the long-run benefits from adaptive WMT. Selective and sustained attention abilities may serve as a scaffold for subsequent changes in higher cognitive processes, academic skills, and general well-being. Furthermore, these results highlight that the selection of outcome measures and the timing of the assessments play a crucial role in detecting training efficacy. Thus, evaluating intra-individual variability, during or directly after training could allow for the early tailoring of training interventions in terms of duration or content to maximise their impact.

The use of the DTO™ hybrid dynamic device: a clinical outcome- and radiological-based prospective clinical trial.

BACKGROUND: The purpose of this study was to assess the radiological and clinical outcome parameters following lumbar hybrid dynamic instrumentation with the focus on the adjacent segment degeneration (ASD) and adjacent segment disease (ASDi). METHODS: In this prospective trial all patients presenting with degenerative changes to the lumbar spine have been included. Precondition was a stable adjacent level with/without degenerative alteration. The elected patients underwent a standardised fusion procedure with hybrid instrumentation (DTO™, Zimmer Spine Inc., Denver, USA). Patients' demographics have been documented and the follow-up visits were conducted after 6 weeks, and then stepwise after 6 up to 48 months. Each follow-up visit included assessment of quality of life and pain using specific questionnaires (COMI, SF-36, ODI) and the radiological evaluation with focus on the adjacent level alterations. RESULTS: At a mean follow up of 24 months an incidence of ASD with 10.91% and for ASDi with 18.18% has been observed. In 9% a conversion to standardised fusion was needed. There was a high rate of mechanical complication: (1) screw loosening (52.73%), (2) pedicle screw breakage (10.91%), and (3) rod breakage (3.64%) after a follow up of a maximum of 60 months. There were no significant difference of COMI, ODI and SF-36(v2) in comparison to all groups but all 55 patients showed a clinical improvement over the time. CONCLUSION: The dynamic hybrid DTO™ device is comparable to the long-term results after standardised fusion procedure, while a high rate of mechanical complication decreased the initial benefit. TRIAL REGISTRATION: This trial was registered at the ClinicalTrials Register ( #NCT03404232 , 2018/01/18, registered retrospectively).

Separation of HIV-1 gag virus-like particles from vesicular particles impurities by hydroxyl-functionalized monoliths.

The downstream processing of enveloped virus-like particles is very challenging because of the biophysical and structural similarity between correctly assembled particles and contaminating vesicular particles present in the feedstock. We used hydroxyl-functionalized polymethacrylate monoliths, providing hydrophobic and electrostatic binding contributions, for the purification of HIV-1 gag virus-like particles. The clarified culture supernatant was conditioned with ammonium sulfate and after membrane filtration loaded onto a 1 mL monolith. The binding capacity was 2 × 1012 /mL monolith and was only limited by the pressure drop. By applying either a linear or a step gradient elution, to decrease the ammonium sulfate concentration, the majority of double-stranded DNA (88-90%) and host cell protein impurities (39-61%) could be removed while the particles could be separated into two fractions. Proteomic analysis and evaluation of the p24 concentration showed that one fraction contained majority of the HIV-1 gag and the other fraction was less contaminated with proteins originated from intracellular compartments. We were able to process up to 92 bed volumes of conditioned loading material within 3 h and eluted in average 7.3 × 1011 particles per particle fraction, which is equivalent to 730 vaccination doses of 1 × 109 particles.

Surfaces energies of monoliths by inverse liquid chromatography and contact angles.

Seven porous chromatographic columns, termed monoliths, and seven nonporous sheets were produced from polymethacrylates. Their surfaces were activated by different densities of butyl and phenyl ligands. We determined the retention times of highly dilute molecular probes in monoliths and accessed contact angles of pure molecular probes of sheets. We calculated surface energies for both systems. We applied theories of Young, Dupré, and van Oss and compared the results of both types of experiments with respect to Lifshitz-van der Waals and Lewis acid and Lewis base contributions and find agreement but an additive constant.

Purification of secretory IgA monoclonal antibodies enriched fraction directly from cell culture medium using aqueous two-phase systems.

Secretory immunoglobulin A [sIgA] is a promising candidate for enteric therapeutics applications, and several sIgA-based constructs are currently being developed by groups utilizing clarified Chinese hamster ovary [CHO] cell culture supernatants. To the monoclonal antibody downstream processing typically entails chromatography-based purification processes beginning with Protein A chromatography. In this paper, aqueous two-phase systems [ATPS] were employed for the preliminary purification of secretory immunoglobulin A [sIgA] monoclonal antibody [mAb] from clarified CHO-cell culture supernatants. A 24 full factorial design was utilized. The influence of various process parameters such as pH, PEG molecular weight [MPEG], PEG concentration [CPEG], and phosphate salt concentration [CPHO], on the sIgA partition coefficient [K sIgA] and the recovery index [Y] in the PEG phase were evaluated. The Elisa assay revealed that, in the ATPS conditions tested, sIgA mAb was mostly detected in PEG upper phase. Run 14 with the highest sIgA activity exhibited the following conditions: MPEG 8.000 g/mol, CPEG 12,5 %, pH 7,0 and CPHO 10 %, and a sIgA K of 94.50 and a recovery index [Y] of 33.52 %. The proposed platform provides straightforward implementation, yields comparable results, and offers significantly improved economics for manufacturing sIgA mAb biotherapeutics.

Teaching self-regulation.

Children's self-regulation abilities are key predictors of educational success and other life outcomes such as income and health. However, self-regulation is not a school subject, and knowledge about how to generate lasting improvements in self-regulation and academic achievements with easily scalable, low-cost interventions is still limited. Here we report the results of a randomized controlled field study that integrates a short self-regulation teaching unit based on the concept of mental contrasting with implementation intentions into the school curriculum of first graders. We demonstrate that the treatment increases children's skills in terms of impulse control and self-regulation while also generating lasting improvements in academic skills such as reading and monitoring careless mistakes. Moreover, it has a substantial effect on children's long-term school career by increasing the likelihood of enroling in an advanced secondary school track three years later. Thus, self-regulation teaching can be integrated into the regular school curriculum at low cost, is easily scalable, and can substantially improve important abilities and children's educational career path.

Packing quality, protein binding capacity and separation efficiency of pre-packed columns ranging from 1 mL laboratory to 57 L industrial scale.

Pre-packed chromatography columns are routinely used in downstream process development and scale-down studies. In recent years they have also been widely adopted for large scale, cGMP manufacturing of biopharmaceuticals. Despite columns being qualified at their point of manufacture before release for sale, the suitability of pre-packed chromatography columns for protein separations at different scales has not yet been demonstrated. In this study, we demonstrated that the performance results obtained with small scale columns (0.5 cm diameter × 5 cm length, 1 mL column volume) are scalable to production sized columns (60 cm diameter × 20 cm length, 57 L column volume). The columns were characterized with acetone and blue dextran pulses to determine the packing density and packed bed consistency. Chromatography performance was evaluated with breakthrough curves including capacity measurements and with separation of a ternary protein mixture (lysozyme, cytochrome C and RNase A) with a step gradient. The equilibrium binding capacity and dynamic binding capacity were equivalent for all columns. The step gradient separation of the ternary protein mixture displayed similar peak profiles when normalized in respect to column volume and the eluted protein pools had the same purities for all scales. Scalable performance of pre-packed columns is demonstrated but as with conventionally packed columns the influence of extra column volume and system configurations, especially buffer mixing, must be taken into account when comparing separations at different scales.

Yeast cell surface display system for determination of humoral response to active immunization with a monoclonal antibody against EpCAM.

Even though an immunogenic formulation of the murine monoclonal anti-EpCAM (epithelian cell adhesion molecule) antibody Mab 17-1A, has been shown to evoke a strong humoral immune response in both, monkey studies and early clinical trials, conventional anti-EpCAM ELISA could not identify anti-EpCAM immune response in relation to treatment with Mab17-1A. In contrast, usage of cellulose membranes prepared by SPOT technology presenting overlapping EpCAM peptides allowed the unequivocal determination of EpCAM related antibodies present in monkeys sera after immunization with IGN101. Based on such contradictory results, it was of high interest to compare obtained data to a different method for better assessment of their possible interpretation. Therefore, in the present studies, some EpCAM peptides, determined as reactive by binding of IgG isolated from sera of treated monkeys on membranes prepared by SPOT technology, were represented on yeast surface using the pYD1 yeast display vector system. Binding of biotinylated IgG from sera was detected with streptavidin-FITC and quantity of binding was determined by FACS measurement. Though using this completely different method, experiments with pre-immune and immune sera of four monkeys exemplarily are comparable to the results obtained by analysis with synthetic peptide arrays.

Impact of Cavitation, High Shear Stress and Air/Liquid Interfaces on Protein Aggregation.

The reported impact of shear stress on protein aggregation has been contradictory. At high shear rates, the occurrence of cavitation or entrapment of air is reasonable and their effects possibly misattributed to shear stress. Nine different proteins (α-lactalbumin, two antibodies, fibroblast growth factor 2, granulocyte colony stimulating factor [GCSF], green fluorescence protein [GFP], hemoglobin, human serum albumin, and lysozyme) are tested for their aggregation behavior on vapor/liquid interfaces generated by cavitation and compared it to the isolated effects of high shear stress and air/liquid interfaces generated by foaming. Cavitation induced the aggregation of GCSF by +68.9%, hemoglobin +4%, and human serum albumin +2.9%, compared to a control, whereas the other proteins do not aggregate. The protein aggregation behaviors of the different proteins at air/liquid interfaces are similar to cavitation, but the effect is more pronounced. Air-liquid interface induced the aggregation of GCSF by +94.5%, hemoglobin +35.5%, and human serum albumin (HSA) +31.1%. The results indicate that the sensitivity of a certain protein toward cavitation is very similar to air/liquid-induced aggregation. Hence, hydroxyl radicals cannot be seen as the driving force for protein aggregation when cavitation occurs. Further, high shear rates of up to 108 s-1 do not affect any of the tested proteins. Therefore, also within this study generated extremely high isolated shear rates cannot be considered to harm structural integrity when processing proteins.

Influence of cavitation and high shear stress on HSA aggregation behavior.

Neither the influence of high shear rates nor the impact of cavitation on protein aggregation is fully understood. The effect of cavitation bubble collapse-derived hydroxyl radicals on the aggregation behavior of human serum albumin (HSA) was investigated. Radicals were generated by pumping through a micro-orifice, ultra-sonication, or chemically by Fenton's reaction. The amount of radicals produced by the two mechanical methods (0.12 and 11.25 nmol/(L min)) was not enough to change the protein integrity. In contrast, Fenton's reaction resulted in 382 nmol/(L min) of radicals, inducing protein aggregation. However, the micro-orifice promoted the formation of soluble dimeric HSA aggregates. A validated computational fluid dynamic model of the orifice revealed a maximum and average shear rate on the order of 108 s-1 and 1.2 × 106 s-1, respectively. Although these values are among the highest ever reported in the literature, dimer formation did not occur when we used the same flow rate but suppressed cavitation. Therefore, aggregation is most likely caused by the increased surface area due to cavitation-mediated bubble growth, not by hydroxyl radical release or shear stress as often reported.

Freestanding ultrathin films for separation of small molecules in an aqueous environment.

Alternative separation methods operating in an aqueous environment are of increasing importance for further progress of molecular separation in life sciences and other industrial sectors working towards a biobased economy. By spincoating, membranes with thicknesses under 100 nm and 20 cm2 surface area were prepared from an epoxy based resin. For the first time such ultrathin epoxy films were used for the selective separation of small molecules and metabolites within an aqueous environment. Initially, selectivity is demonstrated by the separation of two dyes of similar size (0.7 and 1.4 nm diameter). By variation of the precursor concentrations, both mechanical stability and selectivity for molecular transport are shown to be tunable. The observed transport properties of the different membranes correlated with their biaxial moduli and ultimate tensile strengths which were in the range of 0.3-3.5 GPa and 10-44 MPa, respectively. These observations agreed with the conclusion drawn from FTIR analysis that variations in the covalent crosslinking density determine the emergent properties. Finally, permeation rates for small molecules of industrial relevance were assessed to confirm a size based diffusion cutoff for compounds with hydrodynamic diameters below 2 nm.

Quality of life after multiple trauma: the effect of early onset psychotherapy on quality of life in trauma patients.

BACKGROUND AND AIMS: The aim of this study was to improve health-related quality of life (HRQOL) related to depression, anxiety, pain, physical functioning and social aspects for severely injured trauma survivors by early onset cognitive behavioural therapy applied on the surgical ward. MATERIALS AND METHODS: The study was a randomised, controlled study. Of 298 primary screened patients 171 were eligible and randomised. Ninety-two patients adhered to follow-up investigations at 6 and 12 months. Main outcome measure was a sum score according to O'Brien calculated of five different questionnaires (BDI, SF-36, STAI, SCL 90R, F-SOZU-22). RESULTS: The sum score for overall HRQOL did not show significant group differences at follow-up. Effects on HRQOL sub-dimensions within groups have been found. In the dimension of depression therapy group showed significant improvement from the first measurement to discharge from hospital (p < 0.001), 6 MFU (p = 0.004) and to 12 MFU (p = 0.013). Measures of anxiety showed significant improvement for the therapy group at discharge from hospital (p = 0.001). In the control group there was only a significant reduction in depression and anxiety from surgical ward to discharge (p = 0.013/p = 0.031). CONCLUSIONS: Early onset cognitive therapy is not effective in improving overall HRQOL of severely injured patients but shows promising effects on depression and anxiety up to 12 months after trauma.

Quantification and characterization of virus-like particles by size-exclusion chromatography and nanoparticle tracking analysis.

The rapid quantification of enveloped virus-like particles (VLPs) requires orthogonal methods to obtain reliable results. Three methods-nanoparticle tracking analysis (NTA), size-exclusion HPLC (SE-HPLC) with UV detection, and detection with multi-angle light scattering (MALS)-for quantification of enveloped VLPs have been compared, and the lower and upper limits of detection and quantification have been evaluated. NTA directly counts the enveloped VLPs, and a particle number is obtained with a lower limit of detection (LLOD) of 1.7×107part/mL and lower limit of quantification (LLOQ) of 3.4×108part/mL. SE-HPLC with UV detection was calibrated with standards characterized by NTA, and a LLOD of 6.9×109part/mL and LLOQ of 2.1×1010part/mL were found. SE-HPLC with MALS does not require a pre-calibrated sample because with a spherical model based on the Rayleigh-Gans-Debye approximation, the particle concentration can be directly deduced from the scattered light. A LLOD of 4.8×108part/mL and LLOQ of 2.1×109part/mL were measured and substantially lower compared to the UV method. The absolute particle concentration measured by SE-HPLC-MALS is one order of magnitude lower compared to measurement by NTA, which is explained by the wide size distribution of an enveloped VLP suspension. The model used for evaluation of light scattering data assumes monodisperse, homogeneous, and spherical particles.

Faecal steroid metabolites for non-invasive assessment of reproduction in common warthogs (Phacochoerus africanus), red river hogs (Potamochoerus porcus) and babirusa (Babyrousa babyrussa).

The objectives of this study were to analyse faecal steroid metabolites in African and South East Asian pig species kept in European zoos. Species studied were the warthog (Phacochoerus africanus), the red river hog (Potamochoerus porcus) and the babirusa (Babyrousa babyrussa). Faecal samples were collected 1-3 times per week from non-pregnant and pregnant captive female warthogs (n = 9), red river hogs (n = 7) and babirusas (n = 5). Enzyme-immunoassays for faecal progesterone, androgen, and oestrogen metabolites, were tested for their ability to determine follicular and luteal phases. In all three species, oestrous cycles could be monitored with 20alpha-OH- and 20-oxo-pregnane assays. In contrast, oestrogens and androgens were not useful in characterising follicular activity during the oestrous cycle in any species. Faecal 20alpha-OH- and 20-oxo-pregnane values were significantly correlated. Faecal pregnane concentrations revealed species-specific differences. Luteal phase values of 20alpha-OH-pregnanes were considerably higher than 20-oxo-pregnanes; 20alpha-OH-pregnanes were in the range of 3-10 microg/g in warthogs and red river hogs, whereas concentrations were 30-200 microg/g faeces in the babirusa. Regular oestrus cycles had a length of about 35 days in all three species studied. Results indicated a seasonal influence on the occurrence of reproductive cycles in the warthog with anoestrous periods in the European summer. The red river hog was found to be a seasonal and poly oestrous breeder; oestrus cycles started by January and continued until summer. In contrast, the babirusa showed non-seasonal ovarian cyclicity. In pregnant red river hogs, progesterone metabolites were comparable to luteal phase values of the oestrous cycle during the first 3 months of gestation, but did further increase during the last month of pregnancy. Oestrogens and 17-oxo-androstanes were significantly elevated during the second half of gestation. In summary, the reproductive biology of three exotic pig species was studied using non-invasive faecal steroid analysis and these methods were used for comparative investigations of oestrous cycles, pregnancy and seasonality.

Purification of HIV-1 gag virus-like particles and separation of other extracellular particles.

Enveloped virus-like particles (VLPs) are increasingly used as vaccines and immunotherapeutics. Frequently, very time consuming density gradient centrifugation techniques are used for purification of VLPs. However, the progress towards optimized large-scale VLP production increased the demand for fast, cost efficient and scale able purification processes. We developed a chromatographic procedure for purification of HIV-1 gag VLPs produced in CHO cells. The clarified and filtered cell culture supernatant was directly processed on an anion-exchange monolith. The majority of host cell impurities passed through the column, whereas the VLPs were eluted by a linear or step salt gradient; the major fraction of DNA was eluted prior to VLPs and particles in the range of 100-200nm in diameter could be separated into two fractions. The earlier eluted fraction was enriched with extracellular particles associated to exosomes or microvesicles, whereas the late eluting fractions contained the majority of most pure HIV-1 gag VLPs. DNA content in the exosome-containing fraction could not be reduced by Benzonase treatment which indicated that the DNA was encapsulated. Many exosome markers were identified by proteomic analysis in this fraction. We present a laboratory method that could serve as a basis for rapid downstream processing of enveloped VLPs. Up to 2000 doses, each containing 1×10(9) particles, could be processed with a 1mL monolith within 47min. The method compared to density gradient centrifugation has a 220-fold improvement in productivity.

Comparative Analysis of Membrane Vesicles from Three Piscirickettsia salmonis Isolates Reveals Differences in Vesicle Characteristics.

Membrane vesicles (MVs) are spherical particles naturally released from the membrane of Gram-negative bacteria. Bacterial MV production is associated with a range of phenotypes including biofilm formation, horizontal gene transfer, toxin delivery, modulation of host immune responses and virulence. This study reports comparative profiling of MVs from bacterial strains isolated from three widely disperse geographical areas. Mass spectrometry identified 119, 159 and 142 proteins in MVs from three different strains of Piscirickettsia salmonis isolated from salmonids in Chile (LF-89), Norway (NVI 5692) and Canada (NVI 5892), respectively. MV comparison revealed several strain-specific differences related to higher virulence capability for LF-89 MVs, both in vivo and in vitro, and stronger similarities between the NVI 5692 and NVI 5892 MV proteome. The MVs were similar in size and appearance as analyzed by electron microscopy and dynamic light scattering. The MVs from all three strains were internalized by both commercial and primary immune cell cultures, which suggest a potential role of the MVs in the bacterium's utilization of leukocytes. When MVs were injected into an adult zebrafish infection model, an upregulation of several pro-inflammatory genes were observed in spleen and kidney, indicating a modulating effect on the immune system. The present study is the first comparative analysis of P. salmonis derived MVs, highlighting strain-specific vesicle characteristics. The results further illustrate that the MV proteome from one bacterial strain is not representative of all bacterial strains within one species.

Effect of the broadcast of a television documentary about a teenager's suicide in Israel on suicidal behavior and methods.

Portrayals of suicide in the media are controversial because they may impact on suicide rates and methods. The aim of this study was to analyze the effect of the broadcast of a television documentary wherein an adolescent girl is interviewed about her suicide plan and subsequently dies by suicide. National suicide rates during the 8 weeks prior to the program and the 4 weeks following it were compared to the same periods in the previous year. There was no significant difference in the rates of completed and attempted suicides before and after the program. There was a shift toward the method used in the film after the broadcast, but it was found to be nonspecific to that year. A significant decrease was noted in the mean age of suicide attempters in the last promotional week prior to the broadcast compared to the previous year (p = .032). These preliminary findings suggest that the repeated televised promotion of a documentary on suicide may raise the risk of suicide in vulnerable populations. Further investigations in bigger populations are needed.

Clinical potential of methylphenidate in the treatment of cocaine addiction: a review of the current evidence.

BACKGROUND: Cocaine use continues to be a public health problem, yet there is no proven effective pharmacotherapy for cocaine dependence. A promising approach to treating cocaine dependence may be agonist-replacement therapy, which is already used effectively in the treatment of opioid and tobacco dependence. The replacement approach for cocaine dependence posits that administration of a long-acting stimulant medication should normalize the neurochemical and behavioral perturbations resulting from chronic cocaine use. One potential medication to be substituted for cocaine is methylphenidate (MPH), as this stimulant possesses pharmacobehavioral properties similar to those of cocaine. AIM: To provide a qualitative review addressing the rationale for the use of MPH as a cocaine substitute and its clinical potential in the treatment of cocaine dependence. METHODS: We searched MEDLINE for clinical studies using MPH in patients with cocaine abuse/dependence and screened the bibliographies of the articles found for pertinent literature. RESULTS: MPH, like cocaine, increases synaptic dopamine by inhibiting dopamine reuptake. The discriminative properties, reinforcing potential, and subjective effects of MPH and cocaine are almost identical and, importantly, MPH has been found to substitute for cocaine in animals and human volunteers under laboratory conditions. When taken orally in therapeutic doses, its abuse liability, however, appears low, which is especially true for extended-release MPH preparations. Though there are promising data in the literature, mainly from case reports and open-label studies, the results of randomized controlled trials have been disappointing so far and do not corroborate the use of MPH as a substitute for cocaine dependence in patients without attention deficit hyperactivity disorder. CONCLUSION: Clinical studies evaluating MPH substitution for cocaine dependence have provided inconsistent findings. However, the negative findings may be explained by specific study characteristics, among them dosing, duration of treatment, or sample size. This needs to be considered when discussing the potential of MPH as replacement therapy for cocaine dependence. Finally, based on the results, we suggest possible directions for future research.

Surface energies of hydrophobic interaction chromatography media by inverse liquid chromatography.

Hydrophobicity of hydrophobic interaction chromatography media is currently ranked according to retention of reference proteins. A new method, suitable for porous media, is presented here to determine the surface energy and its Lifshitz-van-der-Waals, Lewis acid and Lewis base contributions. The theory of van Oss has been adapted for data obtained by inverse liquid chromatography. Furthermore, this method is characterized by the independence of the determination of the phase ratio. The retention of probes with different molecular properties was used to calculate the surface energy and the Lifshitz-van-der-Waals as well as Lewis acid and Lewis base contributions to the surface energy. The media with polymethacrylate backbone had a higher surface energy (γ ≈ 200 mJ/m(2)) and Lifshitz-van-der-Waals contribution (γ(LW) ≈ 140 mJ/m(2)) than the agarose-based media (γ ≈ 90-180 mJ/m(2) and γ(LW) ≈ 50-160 mJ/m(2)).