Effect of a Toothpaste for Sensitive Teeth on the Sensitivity and Effectiveness of In-office Dental Bleaching: A Randomized Clinical Trial

OBJECTIVES

The present study aimed to evaluate the desensitizing effect of toothpaste for sensitive teeth on patient tooth sensitivity and on bleaching efficacy of the 38% hydrogen peroxide bleaching agent used for in-office bleaching compared to a regular toothpaste in a randomized clinical trial.

METHODS AND MATERIALS

Forty-eight patients having maxillary right central incisors with darkness greater than A1 were selected for the present double-blind randomized clinical trial. Patients were randomly allocated into two groups: the placebo group, which used regular toothpaste, and the experimental group, which used sensitivity toothpaste. The intervention consisted of applying toothpaste with the aid of an individual tray for a period of 4 minutes daily, starting one week before the first bleaching session and interrupting use immediately after the second session. After allocation to one of the groups, individuals received in-office dental bleaching with a 40-minute application of 38% hydrogen peroxide for two sessions with an interval of one week. The incidence and intensity of sensitivity were assessed using a visual analogue scale and a numeric analogue scale. Sensitivity was measured immediately before each session, 1 hour, 24 hours, and 48 hours after each bleaching session and four weeks after the second bleaching session. Tooth shade was evaluated using a spectrophotometer and by comparison with the VITA Classical Shade Guide (Vita Zahnfabrik, Bad Säckingen, Germany). Tooth shade was evaluated before the first bleaching session, one week after the first bleaching session, one week after the second bleaching session and four weeks after the second bleaching session. Participants and professionals who performed the bleaching, shade, and sensitivity assessments were blinded to the group of patients they were treating or assessing. For the incidence of hypersensitivity, the results were evaluated by comparing the groups at different evaluation times with the Mann-Whitney test for comparison between groups, the Friedman test for repeated measures, and the Tukey test for comparison of times. Shade change on the guide was analyzed using the Mann-Whitney test for comparison between groups and the Wilcoxon test for comparison between times. Shade change by the spectrophotometer was analyzed using the t-test for comparison between groups and the paired t-test for comparison between times. All analyses were performed with a significance level of 5%.

RESULTS

There was no difference in the pattern of dental hypersensitivity between groups. For all shade measures, there was no difference between the bleaching results, and no statistically significant difference was observed between the study groups.

CONCLUSION

The use of arginine-based desensitizing toothpaste did not interfere with the bleaching ability of hydrogen peroxide and was not effective in reducing the sensitivity caused by in-office tooth bleaching.

Effect of Time and Temperature of Air Jet on the Mechanical and Biological Behavior of a Universal Adhesive System

OBJECTIVES

To evaluate the influence of heat application on the degree of conversion (DC) of the 3M Single Bond Universal Adhesive System, as well as its transdentinal cytotoxicity and microtensile bond strength to dentin.

METHODS

Experimental groups were established according to the time and temperature of the air jet: G1: 5 seconds-25°C; G2: 10 seconds-25°C; G3: 20 seconds-25°C; G4: 5 seconds-50°C; G5: 10 seconds-50°C; G6: 20 seconds-50°C. In control group (G7), no treatment was performed. The DC was assessed using the Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) technique. For the transdentinal cytotoxicity test, dentin discs fitted in artificial pulp chambers (APC) received the application of the adhesive system and the air jets. For the microtensile bond strength, healthy molars were restored and submitted to the microtensile test after 24 hours and 6 months, respectively.

RESULTS

Significant reduction in viability of Mouse Dental Papilla Cell-23 (MDPC-23), which exhibited morphological changes, was observed in all experimental groups compared to control (p<0.05). Although all tested protocols resulted in transdentinal diffusion of 2-hydroxyethyl methacrylate (HEMA), the group G6 presented the highest degree of monomeric conversion and the lowest cytotoxic effect, with higher dentin bond strength values in comparison to group G1 (p<0.05).

CONCLUSIONS

Applying an air blast at 50°C for 20 seconds increases the DC and microtensile bond strength of the 3M Single Bond Universal Adhesive System to dentin, as well as reduces the transdentinal cytotoxicity of the material to pulp cells.

39 FACTORS INFLUENCING THE EFFICIENCY OF GENERATING GENETICALLY ENGINEERED PIGS BY NUCLEAR TRANSFER: MULTI-FACTORIAL ANALYSIS OF A LARGE DATA SET

Somatic cell nuclear transfer (SCNT) using genetically engineered donor cells is currently the most widely used strategy to generate genetically tailored pig models for biomedical research. Although this approach facilitates a similar spectrum of genetic modifications as in rodent models, including inducible transgene expression and gene targeting, the outcome in terms of live cloned piglets is quite variable. We used a large data set from 274 SCNT experiments (in total, 18 649 reconstructed embryos transferred into 193 recipients), performed over a period of 3 years, and evaluated it by multivariate analysis for combined assessment of multiple factors and their relative contribution to the efficiency of generation of genetically modified cloned pigs. Specifically, we addressed the effects of season, type of genetic modification (additive gene transfer v. gene targeting), donor cell source (mesenchymal stem cells, postnatal fibroblasts, fetal fibroblasts, and kidney cells), serial NT, and pre-selection of SCNT embryos for early development. Target parameters were pregnancy and delivery rates, as well as the numbers of born, live, and healthy offspring. Cloning efficiency was calculated as the number of cloned piglets relative to the number of transferred SCNT embryos. We used robust linear models adjusted to the underlying empirical distribution of the cloning outcome, as a straightforward approach to determine the statistically significant part of the network of factors affecting pig cloning. The SCNT experiments performed during the winter using fetal fibroblasts or kidney cells after additive gene transfer resulted in the highest number of live and healthy offspring, whereas sequential NT and NT experiments performed during the summer decreased it. Although the effects of individual factors may be different between various laboratories, the statistical approach described in this study may help to identify and optimize the most critical specific factors to cloning success in programs aimed at the generation of genetically engineered pig models. Supported by the DFG (FOR535, FOR793), the Bayerische Forschungsstiftung, and Mukoviszidose e.V.

Drug-eluting stents and drug-coated balloons in peripheral artery disease

Restenosis remains a major problem after angioplasty in peripheral artery disease despite stenting. It occurs in 30 - 50% / year depending on lesion localization and characteristics. One main reason for restenosis is neointimal hyperplasia, which can be suppressed by the topical administration of antiproliferative drugs. In percutaneous coronary intervention the concept of "local drug delivery" has been used for almost a decade with great success. In recent years, drug-eluting stents and drug coated balloons have also been increasingly used in the treatment of peripheral arterial disease as a consequence of positive results of clinical trails. The following article is an overview of the currently available data of completed trials, ongoing and planned studies. Evidence suggests that "drug-coating technology" is reliable, safe and efficient in reducing the target lesion revascularization and binary restenosis rate significantly. With regard to limb salvage and mortality in critical limb ischemia, there is no benefit shown in current published studies.

The Motor-Proficiency-Test for children between 4 and 6 years of age (MOT 4-6): an investigation of its suitability in Greece

Given the negative influence of motor difficulties on people's quality of life their early identification seems to be crucial and consequently the information provided by a sound assessment tool is of great importance. The aim of this study was to examine the suitability of the MOT 4-6 (Zimmer & Volkamer, 1987) for use with preschoolers in Greece. Seven hundred and seventy-eight Greek children aged 48-71 months participated in the study. The two-way ANOVA used on total MOT performance revealed significant differences among the age groups formed in preschool age within Greeks, while boys' and girls' scores were quite similar. From the comparisons of Greeks' scores with the German standardization sample's ones, statistically significant differences were found in two age groups. However according to the Cohen's d effect size they were not of great importance. The distribution of Greeks' scores according to the test cut-offs, revealed that the MOT can differentiate all levels of performance, although a slight deviation from the distribution of Germans' scores was noticed. Finally, both the test-retest reliability and internal consistency of the test were found to be excellent. The MOT 4-6 seems to be a valuable motor assessment tool for Greek preschoolers. Regarding its norms, despite the minor differences that were noticed between the motor development of Greek and German preschoolers, their adjustment was thought to be unnecessary. Instead of lowering the norms, efforts for preventing the motor performance decline should be enhanced.

Normalization strategies for mRNA expression data in cartilage research

OBJECTIVE

Normalization of mRNA data, i.e., the calculation of mRNA expression values comparable in between different experiments, is a major issue in biomedical and orthopaedic/rheumatology research, both for single-gene technologies [Northern blotting, conventional and quantitative polymerase chain reaction (qPCR)] and large-scale gene expression experiments. In this study, we tested several established normalization methods for their effects on gene expression measurements.

METHOD

Five standard normalization strategies were applied on a previously published data set comparing peripheral and central late stage osteoarthritic cartilage samples.

RESULTS

The different normalization procedures had profound effects on the distribution as well as the significance values of the gene expression levels. All applied normalization procedures, except the median absolute deviation scaling, showed a bias towards up- or down-regulation of genes as visualized in volcano plots. Of interest, the P-values were much more depending on the normalization procedure than the fold changes. Ten commonly used housekeeping genes showed a significant variability in between the different specimens investigated. The gene expression analysis by cDNA arrays was confirmed for these genes by qPCR.

CONCLUSION

This study documents how much normalization strategies influence the outcome of gene expression profiling analysis (i.e., the detection of regulated genes). Different normalization approaches can significantly change the P-values and fold changes of a large number of genes. Thus, it is of vital importance to check every individual step of gene expression data analysis for its appropriateness. The use of global robustness and quality measures for analyzing individual outcomes can help in estimating the reliability of final microarray study results.

Microisolation of the chicken Z chromosome and construction off microclone libraries

A simple method was used to adapt a standard light microscope for the collection of chicken Z chromosomes from mitotic-metaphase spreads. The DNA of the collected chromosomes was enzymatically amplified using a partially degenerate primer. The resulting sequences, within a size range of 200-800 bp, were cloned to produce a Z chromosome DNA library, using blunt-end ligation into a SmaI-digested pUC18 plasmid (the SureClone system; Pharmacia, U.S.A.). The microcloning experiments produced 1250 clones; the size range of the cloned inserts was 250-800 bp, with an average of 480 bp (176 clones examined). Using male chicken genomic DNA as a probe, 10 out of 17 randomly selected clones showed strong positive signals on Southern blots, confirming the origin of the inserts as chicken DNA. In addition, the Z-chromosome origin of a selected microclone was verified in a semiquantitative Southern blot hybridization that showed positive signals with intensities that were approximately twice as strong for male (ZZ) as for female (ZW) chicken genomic DNA when the clone was used as a probe. The value of these libraries in further analysis of the chicken Z chromosome is discussed.

IL-1β, but not BMP-7 leads to a dramatic change in the gene expression pattern of human adult articular chondrocytes—Portraying the gene expression pattern in two donors

Anabolic and catabolic cytokines and growth factors such as BMP-7 and IL-1beta play a central role in controlling the balance between degradation and repair of normal and (osteo)arthritic articular cartilage matrix. In this report, we investigated the response of articular chondrocytes to these factors IL-1beta and BMP-7 in terms of changes in gene expression levels. Large scale analysis was performed on primary human adult articular chondrocytes isolated from two human, independent donors cultured in alginate beads (non-stimulated and stimulated with IL-1beta and BMP-7 for 48 h) using Affymetrix gene chips (oligo-arrays). Biostatistical and bioinformatic evaluation of gene expression pattern was performed using the Resolver software (Rosetta). Part of the results were confirmed using real-time PCR. IL-1beta modulated significantly 909 out of 3459 genes detectable, whereas BMP-7 influenced only 36 out of 3440. BMP-7 induced mainly anabolic activation of chondrocytes including classical target genes such as collagen type II and aggrecan, while IL-1beta, both, significantly modulated the gene expression levels of numerous genes; namely, IL-1beta down-regulated the expression of anabolic genes and induced catabolic genes and mediators. Our data indicate that BMP-7 has only a limited effect on differentiated cells, whereas IL-1beta causes a dramatic change in gene expression pattern, i.e. induced or repressed much more genes. This presumably reflects the fact that BMP-7 signaling is effected via one pathway only (i.e. Smad-pathway) whereas IL-1beta is able to signal via a broad variety of intracellular signaling cascades involving the JNK, p38, NFkB and Erk pathways and even influencing BMP signaling.

Lebenszufriedenheit transsexueller Patienten nach geschlechtsangleichenden Operationen

BACKGROUND

More and more frequently, the registration of life satisfaction is being used to evaluate different medical treatments. So far, there have been only few such surveys on transsexuals (TS). Therefore, the aim of this study was to evaluate the general and the health-related life satisfaction of transsexuals after gender transformation operations.

PATIENTS AND METHODS

Forty patients took part in this German cross-sectional study. The Questions on Life Satisfaction Module (FLZ) and free questions on different aspects of the new gender identity were used as measuring instruments.

RESULTS

Of the TS studied, 85-95% were "very satisfied" or "satisfied" with the results of their gender transformation operation in respect to gender identity. The TS were significantly less satisfied (P>0.001) in overall "general life satisfaction" than the general population. In overall FLZ scores for "health-related life satisfaction", no differences were seen.

CONCLUSION

These data indicate a discrepancy between subjective satisfaction with new gender identity and current life situation, and they identify problems with life satisfaction.

Comparison of the chondrosarcoma cell line SW1353 with primary human adult articular chondrocytes with regard to their gene expression profile and reactivity to IL-1beta

OBJECTIVE

In this study, the human chondrosarcoma cell line SW1353 was investigated by gene expression analysis in order to validate it as an in vitro model for primary human (adult articular) chondrocytes (PHCs).

METHODS

PHCs and SW1353 cells were cultured as high density monolayer cultures with and without 1ng/ml interleukin-1beta (IL-1beta). RNA was isolated and assayed using a custom-made oligonucleotide microarray representing 312 chondrocyte-relevant genes. The expression levels of selected genes were confirmed by real-time polymerase chain reaction and the gene expression profiles of the two cell types, both with and without IL-1beta treatment, were compared.

RESULTS

Overall, gene expression profiling showed only very limited similarities between SW1353 cells and PHCs at the transcriptional level. Similarities were predominantly seen with respect to catabolic effects after IL-1beta treatment. In both cell systems matrix metalloproteinase-1 (MMP-1), MMP-3 and MMP-13 were strongly induced by IL-1beta, without significant induction of MMP-2. IL-6 was also found to be up-regulated by IL-1beta in both cellular models. On the other hand, intercellular mediators such as leukemia inhibitory factor (LIF) and bone morphogenetic protein-2 (BMP-2) were not induced by IL-1beta in SW1353 cells, but significantly up-regulated in PHCs. Bioinformatical analysis identified nuclear factor kappa-B (NFkappaB) as a common transcriptional regulator of IL-1beta induced genes in both SW1353 cells and PHCs, whereas other transcription factors were only found to be relevant for individual cell systems.

CONCLUSION

Our data characterize SW1353 cells as a cell line with only a very limited potential to mimic PHCs, though SW1353 cells can be of value to study the induction of protease expression within cells, a phenomenon also seen in chondrocytes.

The Helmholtz Network for Bioinformatics: an integrative web portal for bioinformatics resources

SUMMARY

The Helmholtz Network for Bioinformatics (HNB) is a joint venture of eleven German bioinformatics research groups that offers convenient access to numerous bioinformatics resources through a single web portal. The 'Guided Solution Finder' which is available through the HNB portal helps users to locate the appropriate resources to answer their queries by employing a detailed, tree-like questionnaire. Furthermore, automated complex tool cascades ('tasks'), involving resources located on different servers, have been implemented, allowing users to perform comprehensive data analyses without the requirement of further manual intervention for data transfer and re-formatting. Currently, automated cascades for the analysis of regulatory DNA segments as well as for the prediction of protein functional properties are provided.

AVAILABILITY

The HNB portal is available at http://www.hnbioinfo.de

Mini-infarct encephalopathy associated with uncommon microvessel convolute formation presenting with presenile dementia

A female patient started to suffer from transient ischemic attacks when she was 47 years of age, followed by increasing predominantly left-side spastic tetraparesis, generalized seizures and progressive dementia over a period of 11 years. She died when she was 58 years of age. On gross examination the brain showed enlarged ventricles and arteriosclerotic changes of large extracerebral vessels of the circulus arteriosus. Microscopic examination of the atrophic brain showed innumerable incomplete microinfarcts in the white and gray matter throughout all parts of the brain. In the white matter these lesions were characterized by small foci of demyelination and loss of oligodendrocytes while occasionally some scavenger cells were seen. Axons seemed to be unaffected or displayed irregular axonal regeneratory growth. Any inflammatory reaction failed. In the cerebral cortex and subcortical nuclei the lesions showed loss of neurons and decrease in synaptophysin expression. Intracerebral arteries showed fibrosis or fibrohyalinosis of the entire intracerebral small-vessel network. In addition, numerous uncommon clusters of angioma-like telangiectatic vessels were observed. Medium-sized ischemic infarcts were found in the right putamen and adjacent internal capsule region, left-side dorsolateral brain stem and cerebellar hemisphere as well as a left-side pyramidal tract degeneration. Contralateral pseudohypertrophy of the inferior olivary nucleus was seen. The clinical and the neuropathologic observations made in this patient are compatible with small vessel disease characterized by a multicentric special and not yet described type of incomplete mini-infarcts in cerebral cortex and white matter accompanied by some larger ischemic infarcts of the common type in brain stem and cerebellum.

Secondary ion and laser ablation mass spectrometry for the quantitative characterization of styrene-butadiene copolymers

Styrene-butadiene copolymers were analyzed by static secondary ion mass spectrometry (S-SIMS) and laser ablation Fourier transform ion cyclotron resonance mass spectrometry (LA-FTICRMS) to obtain quantitative information based on specific ions. Silver deposition was performed on polystyrene, butadiene rubber and styrene-butadiene rubber. Under these experimental conditions, new secondary ions were detected, in particular silver-cationized butadiene [M(butadiene) - Ag](+) and styrene [M(styrene) - Ag](+) monomers. In contrast, LA-FTICRMS experiments did not require pretreatment. At high laser power density, UV photons (193, 266 and 355 nm) allowed the detection of styrene and butadiene monomers at m/z 104 and 54, respectively. The use of the observed ions by SIMS or LA-FTICRMS ensures that quantitative information on the relative distribution of each monomer is obtained. However, the silver coating thickness in the SIMS experiment seems to have an important influence on the quantitative information obtained. For LA-FTICRMS experiments, the best results are obtained at a wavelength of 355 nm.

Interaction Between Rubber and Carbon Black Studied by ToF-SIMS

In order to study the rubber—carbon black filler interaction, different styrene-butadiene rubbers were adsorbed from solution on carbon black. Afterwards, the samples were washed to keep only the thin layer of bound rubber. The surface of these samples was characterized by ToF-SIMS. It was found that the carbon black surface was completely covered by the polymer, except for pure 1,4-polybutadiene where a non-uniform adsorption was seen. Moreover, the ToF-SIMS data showed that the parameters related to the polymer aromaticity and unsaturation decreased after adsorption. These results indicated a change in polymer chain conformation at the surface upon adsorption on carbon black. This was explained by a preferential interaction between phenyl (and in a weaker manner, 1,2-vinyl) groups with the carbon black surface. Indeed, when these groups tend to orientate toward the filler surface, their surface concentration seen by ToF-SIMS is expected to decrease.

Noninvasive drug delivery

Advances in biopharmaceutical technology have spawned new drug delivery devices and mechanisms. Noninvasive methods, including iontophoresis and transmucosal drug delivery, have improved treatment of certain patient population. Their use is discussed in the following paper.

Centralization: a new method for the normalization of gene expression data

Microarrays measure values that are approximately proportional to the numbers of copies of different mRNA molecules in samples. Due to technical difficulties, the constant of proportionality between the measured intensities and the numbers of mRNA copies per cell is unknown and may vary for different arrays. Usually, the data are normalized (i.e., array-wise multiplied by appropriate factors) in order to compensate for this effect and to enable informative comparisons between different experiments. Centralization is a new two-step method for the computation of such normalization factors that is both biologically better motivated and more robust than standard approaches. First, for each pair of arrays the quotient of the constants of proportionality is estimated. Second, from the resulting matrix of pairwise quotients an optimally consistent scaling of the samples is computed.

Heterogeneous RNA-binding protein M4 is a receptor for carcinoembryonic antigen in Kupffer cells

Here we report the isolation of the recombinant cDNA clone from rat macrophages, Kupffer cells (KC) that encodes a protein interacting with carcinoembryonic antigen (CEA). To isolate and identify the CEA receptor gene we used two approaches: screening of a KC cDNA library with a specific antibody and the yeast two-hybrid system for protein interaction using as a bait the N-terminal part of the CEA encoding the binding site. Both techniques resulted in the identification of the rat heterogeneous RNA-binding protein (hnRNP) M4 gene. The rat ortholog cDNA sequence has not been previously described. The open reading frame for this gene contains a 2351-base pair sequence with the polyadenylation signal AATAAA and a termination poly(A) tail. The mRNA shows ubiquitous tissue expression as a 2.4-kilobase transcript. The deduced amino acid sequence comprised a 78-kDa membrane protein with 3 putative RNA-binding domains, arginine/methionine/glutamine-rich C terminus and 3 potential membrane spanning regions. When hnRNP M4 protein is expressed in pGEX4T-3 vector system in Escherichia coli it binds (125)I-labeled CEA in a Ca(2+)-dependent fashion. Transfection of rat hnRNP M4 cDNA into a non-CEA binding mouse macrophage cell line p388D1 resulted in CEA binding. These data provide evidence for a new function of hnRNP M4 protein as a CEA-binding protein in Kupffer cells.

Monitoring Thermal Oxidation of Sulfur Crosslinks in SBR-Elastomers by Quantitative Analysis of Sulfur K-Edge XANES-Spectra

This paper presents a quantitative description of the processes occurring at the sulfur crosslinks of vulcanized rubber during thermo-oxidative aging. To extract this information in a nondestructive way, sulfur K-edge X-ray absorption near-edge structure (XANES) spectra have been analyzed quantitatively. We find that reversion takes place before the onset of oxidative processes at the sulfur bridges. Parallel to the oxidative processes, the production of cyclic sulfanes takes place. Both the relative and absolute contributions of the different reactions involving the sulfur crosslinks vary strongly with sample composition. Whereas antidegradants delay the thermo-oxidative aging without actually changing the aging resistance of the sulfur bonds, both the amount of S8/TBBS (N-tert-butylbenzothiazole-2-sulfenamide) and the presence of carbon black in the sample enhance this parameter considerably.

A simple iterative approach to parameter optimization

Various bioinformatics problems require optimizing several different properties simultaneously. For example, in the protein threading problem, a scoring function combines the values for different parameters of possible sequence-to-structure alignments into a single score to allow for unambiguous optimization. In this context, an essential question is how each property should be weighted. As the native structures are known for some sequences, a partial ordering on optimal alignments to other structures, e.g., derived from structural comparisons, may be used to adjust the weights. To resolve the arising interdependence of weights and computed solutions, we propose a heuristic approach: iterating the computation of solutions (here, threading alignments) given the weights and the estimation of optimal weights of the scoring function given these solutions via systematic calibration methods. For our application (i.e., threading), this iterative approach results in structurally meaningful weights that significantly improve performance on both the training and the test data sets. In addition, the optimized parameters show significant improvements on the recognition rate for a grossly enlarged comprehensive benchmark, a modified recognition protocol as well as modified alignment types (local instead of global and profiles instead of single sequences). These results show the general validity of the optimized weights for the given threading program and the associated scoring contributions.

Mutations in the carcinoembryonic antigen gene in colorectal cancer patients: implications on liver metastasis

Carcinoembryonic antigen (CEA) expression is used clinically to monitor patients with colorectal and other cancers. A subset of patients have extraordinarily high CEA levels that cannot be attributed solely to tumor load. We have shown mutations in the region of CEA (PELPK motif) responsible for its hepatic clearance in three of eight patients with high CEA levels. We used denaturing high-performance liquid chromatography to provide evidence of polymorphism in these patients. These mutations were scored by DNA cycle sequencing and shown to be heterozygous. The patients with mutations in the PELPK motif showed remarkably reduced circulatory clearance rates in an animal model. A patient without mutation in the region showed normal clearance rates. Mutations in PELPK may affect structural stability and binding affinity to the Kupffer cell receptor in the liver. These studies have implications for the role of CEA as a facilitator of hepatic metastasis.

Analysis of gene expression data with pathway scores

We present a new approach for the evaluation of gene expression data. The basic idea is to generate biologically possible pathways and to score them with respect to gene expression measurements. We suggest sample scoring functions for different problem specifications. We assess the significance of the scores for the investigated pathways by comparison to a number of scores for random pathways. We show that simple scoring functions can assign statistically significant scores to biologically relevant pathways. This suggests that the combination of appropriate scoring functions with the systematic generation of pathways can be used in order to select the most interesting pathways based on gene expression measurements.