Tero Aittokallio

Probe-level estimation improves the detection of differential splicing in Affymetrix exon array studies (2009)

Laajala, Essi, Aittokallio, Tero, Lahesmaa, Riitta, Elo, Laura L

Abstract The recent advent of exon microarrays has made it possible to reveal differences in alternative splicing events on a global scale. We introduce a novel statistical procedure that takes full...

Geometrical Distortions in Two-Dimensional Gels: Applicable Correction Methods (2009)

Aittokallio, Tero, Salmi, Jussi, Nyman, Tuula A., Nevalainen, Olli S.

Two-dimensional electrophoresis (2-DE) provides a rapid means for separating thousands of proteins from cell and tissue samples in one run. Although this powerful research tool has been...

Optimized detection of differential expression in global profiling experiments: case studies in clinical transcriptomic and quantitative proteomic datasets (2009)

Elo, Laura L., Hiissa, Jukka, Tuimala, Jarno, Kallio, Aleksi, Korpelainen, Eija, Aittokallio, Tero

Identification of reliable molecular markers that show differential expression between distinct groups of samples has remained a fundamental research problem in many large-scale profiling studies,...

Genoscape: a Cytoscape plug-in to automate the retrieval and integration of gene expression data and molecular networks (2009)

Clément-Ziza, Mathieu, Malabat, Christophe, Weber, Christian, Moszer, Ivan, Aittokallio, Tero, Letondal, Catherine, ...

Summary: Genoscape is an open-source Cytoscape plug-in that visually integrates gene expression data sets from GenoScript, a transcriptomic database, and KEGG pathways into Cytoscape networks. The...

Identification of Novel IL-4/Stat6-Regulated Genes in T (2008)

Zhi Chen, Riikka Lund, Tero Aittokallio, Minna Kosonen, Olli Nevalainen, Riitta Lahesmaa

IL-4, primarily produced by T cells, mast cells, and basophiles, is a cytokine which has pleiotropic effects on the immune system. IL-4 induces T cells to differentiate to Th2 cells and activated B...

Filtering strategies for improving protein identification in high-throughput MS/MS studies (2008)

Salmi, Jussi, Nyman, Tuula A., Nevalainen, Olli S., Aittokallio, Tero

Despite the recent advances in streamlining high-throughput proteomic pipelines using tandem mass spectrometry (MS/MS), reliable identification of peptides and proteins on a larger scale has remained...

Missing value imputation improves clustering and interpretation of gene expression microarray data (2008)

Tuikkala, Johannes, Elo, Laura L, Nevalainen, Olli S, Aittokallio, Tero

Abstract Background Missing values frequently pose problems in gene expression microarray experiments as they can hinder downstream analysis of the datasets. While several missing value imputation...

Golorize: a cytoscape plug-in for network visualization with gene ontology-based layout and coloring (2008)

Olivier Garcia, Cosmin Saveanu, Melissa Cline, Micheline Fromont-racine, Alain Jacquier, Benno Schwikowski, ...

Summary: We have implemented a graph layout algorithm that exposes Gene Ontology (GO) class structure on the network nodes. It can be used in conjunction with BiNGO plug-in to Cytoscape, which finds...

BIOINFORMATICS Quality classification of tandem mass spectrometry data (2008)

Jussi Salmi, Robert Moulder, Jan-jonas Filén, Olli S. Nevalainen, Tuula A. Nyman, Riitta Lahesmaa, ...

Motivation: Peptide identification by tandem mass spectrometry is an important tool in proteomic research. Powerful identification programs exist, such as SEQUEST, ProICAT and Mascot, which can...

A Multilevel Graph Layout Algorithm for Cytoscape Bioinformatics Software Platform (2008)

Salmela, Pekka, Nevalainen, Olli S., Aittokallio, Tero

We have implemented a graph layout algorithm of C. Walshaw as a plug-in in the Cytoscape bioinformatics software platform. The algorithm combines traditional forcedirected placement of graphs with an...

Model-based prediction of sequence alignment quality (2008)

Ahola, Virpi, Aittokallio, Tero, Vihinen, Mauno, Uusipaikka, Esa

Motivation: Multiple sequence alignment (MSA) is an essential prerequisite for many sequence analysis methods and valuable tool itself for describing relationships between protein sequences. Since...

BioMed Central (2008)

Bmc Bioinformatics, Johannes Tuikkala, Laura L Elo, Olli S Nevalainen, Tero Aittokallio

Research article Missing value imputation improves clustering and interpretation of gene expression microarray data

Olli Polo (2007)

Tero Aittokallio

In snorers, the physiologic decrease of postural muscle tone during sleep results in increased collapsibility of the upper airway. This paper presents a mathematical model for the collapsible upper...

Automated Detection of Dioeerentially Expressed Fragments in mRNA Dioeerential Display (2007)

Tero Aittokallio, Olli Nevalainen, Pekka Ojala, Timo J. Nevalainen

We present a novel method for the automated detection of fragments showing dissimilar expression in mRNA dioeerential display. The analysis is based on aligning the numerical electrophoretic lane...

Olli Polo (2007)

Tero Aittokallio, Mats Gyllenberg, Olli Nevalainen

A simple method for detecting periodic components of unknown periodicity in a signal is presented. The method is based on spectral decomposition of signal using orthonormal functions. Traditionally,...

Computation of Standard Errors for Maximum-likelihood Estimates in Hidden Markov Models (2007)

Tero Aittokallio, Esa Uusipaikka

Explicit computation of the score vector and the observed information matrix in hidden Markov models is described. With the help of the information matrix Wald's condence intervals can be formed...

Computation of Restricted Maximum-penalized-likelihood Estimates in Hidden Markov Models (2007)

Tero Aittokallio, Olli Nevalainen, Jussi Tolvi, Kalle Lertola, Esa Uusipaikka

The maximum-penalized-likelihood estimation for hidden Markov models with general observation densities is described. All statistical inference, including the model estimation, testing, and...

Olli Polo (2007)

Tero Aittokallio, Mats Gyllenberg

A cardiorespiratory model incorporating control of the human upper airway during sleep is described. Most previous models have not considered the possibility that the upper airway could be a limiting...

Systematic construction of gene coexpression networks with applications to human T helper cell differentiation process (2007)

Elo, Laura L., Järvenpää, Henna, Oresic, Matej, Lahesmaa, Riitta, Aittokallio, Tero

Motivation: Coexpression networks have recently emerged as a novel holistic approach to microarray data analysis and interpretation. Choosing an appropriate cutoff threshold, above which a...

Predicting Gene Expression from Combined Expression and Promoter Profile Similarity with Application to Missing Value Imputation (2007)

Elo, Laura L., Tuikkala, Johannes, Nevalainen, Olli S., Aittokallio, Tero

Gene expression microarrays have become a popular high-throughput technique in functional genomics. By enabling the monitoring of thousands of genes simultaneously, this technique holds enormous...

Biochemical and Clinical Approaches in Evaluating the Prognosis of Colonic Cancer (2007)

Talvinen, Kati, Tuikkala, Johannes, Grönroos, Juha, Huhtinen, Heikki, Kronqvist, Pauliina, Aittokallio, Tero, ...

Background: Colorectal adenocarcinoma is a common malignant neoplasm in the western world. To achieve optimal treatment results, the estimation of risk of recurrence should be as accurate as...

Inspiratory Flow Shape Clustering: An Automated Method to Monitor Upper Airway Performance During Sleep (2007)

Aittokallio, Tero, Malminen, Jani S., Pahikkala, Tapio, Polo, Olli, Nevalainen, Olli S.

We describe an automated method for monitoring airflow dynamics in the upper airway of a sleeping subject. Its main task is to determine a set of inspiratory flow shape representatives...

GOlorize: a Cytoscape plug-in for network visualization with Gene Ontology-based layout and coloring (2007)

Garcia, Olivier, Saveanu, Cosmin, Cline, Melissa, Fromont-Racine, Micheline, Jacquier, Alain, Schwikowski, Benno, ...

Summary: We have implemented a graph layout algorithm that exposes Gene Ontology (GO) class structure on the network nodes. It can be used in conjunction with BiNGO plug-in to Cytoscape, which finds...

A statistical score for assessing the quality of multiple sequence alignments (2006)

Ahola, Virpi, Aittokallio, Tero, Vihinen, Mauno, Uusipaikka, Esa

Abstract Background Multiple sequence alignment is the foundation of many important applications in bioinformatics that aim at detecting functionally important regions, predicting protein structures,...

Filtering Bad Quality Tandem Mass Spectra Prior to Protein Identification (2006)

Salmi, Jussi, Moulder, Robert, Filén, Jan-Jonas, Nevalainen, Olli S., Lahesmaa, Riitta, Nyman, Tuula A., ...

The identification of proteins is an important task in proteomics. Protein or peptide identification from mass spectrometry data is usually accomplished by using database search programs which match...

Model-Based Analysis of Mechanisms Responsible for Sleep-Induced Carbon Dioxide Differences (2006)

Aittokallio, Tero, Gyllenberg, Mats, Polo, Olli, Toivonen, Jenni, Virkki, Arho

This work describes a comprehensive mathematical model of the human respiratory control system which incorporates the central mechanisms for predicting sleep-induced changes in chemical regulation of...

Quality Classification of Tandem Mass Spectrometry Data (2006)

Salmi, Jussi, Moulder, Robert, Filén, Jan-Jonas, Nevalainen, Olli S., Nyman, Tuula A., Lahesmaa, Riitta, ...

Motivation: Peptide identification by tandem mass spectrometry is an important tool in proteomic research. Powerful identification programs exist, such as SEQUEST, ProICATand Mascot, which can relate...

Non-invasive Respiratory Monitoring During Wakefulness and Sleep in Pre- and Postmenopausal Women (2006)

Aittokallio, Jenni, Virkki, Arho, Aittokallio, Tero, Saaresranta, Tarja, Polo-Kantola, Päivi, Polo, Olli

Menopause and aging cause hormonal changes with respiratory consequences. The aim of the present study was to investigate the physiological changes in respiration during wakefulness and sleep across...

Inference of Gene Coexpression Networks by Integrative Analysis across Microarray Experiments (2006)

Elo, Laura L., Lahesmaa, Riitta, Aittokallio, Tero

We improve the reliability of detecting coexpressed gene pairs from microarray data by introducing a novel probe-level quality-weighted similarity measure for combining data across different...

Gene Ontology-based layout and coloring (2006)

Olivier Garcia, Cosmin Saveanu, Melissa Cline, Micheline Fromont-racine, Alain Jacquier, Benno Schwikowski, ...

doi:10.1093/bioinformatics/btl605 GOlorize: a Cytoscape plug-in for network visualization with

Improving missing value estimation in microarray data with gene ontology (2006)

Tuikkala, Johannes, Elo, Laura, Nevalainen, Olli S., Aittokallio, Tero

Motivation: Gene expression microarray experiments produce datasets with frequent missing expression values. Accurate estimation of missing values is an important prerequisite for efficient data...

Graph-based methods for analysing networks in cell biology (2006)

Aittokallio, Tero, Schwikowski, Benno

Availability of large-scale experimental data for cell biology is enabling computational methods to systematically model the behaviour of cellular networks. This review surveys the recent advances in...

Filtering Bad Quality Tandem Mass Spectra Prior to Protein Identification (2005)

Salmi, Jussi, Moulder, Robert, Filén, Jan-Jonas, Nevalainen, Olli S., Lahesmaa, Riitta, Nyman, Tuula A., ...

An important task in proteomics is the identification of peptides from tandem mass spectrometry data. Peptide identification is usually accomplished by using database search programs which match the...

Considerations when Using Gene Expression Microarray Data to Diagnostic Classification (2005)

Pahikkala, Tapio, Nikula, Tuomas, Mykkänen, Juha, Näntö-Salonen, Kirsti, Simell, Olli, Lahesmaa, Riitta, ...

Gene expression microarrays provide a powerful tool for biomedical research. However, there are a number of challenging problems that need to be considered before applying microarray data in...

Improving Missing Value Estimation in Microarray Data with Gene Ontology (2005)

Tuikkala, Johannes, Nevalainen, Olli S., Aittokallio, Tero

Gene expression microarray experiments produce data sets with frequent missing expression values. Accurate estimation of missing values is an important prerequisite for efficient data analysis as...

A Human ImmunoChip cDNA Microarray Provides a Comprehensive Tool to Study Immune Responses (2005)

Nikula, Tuomas, West, Anne, Katajamaa, Mikko, Lönnberg, Tapio, Sara, Rolf, Aittokallio, Tero, ...

DNA microarray technology has developed rapidly in recent years and has become an essential tool, providing novel approaches to biomedical research. In this paper, we describe a self-designed...

A Comparative Evaluation of Software for the Analysis of Liquid Chromatography-Tandem Mass Spectrometry Data from Isotope Coded Affinity Tag Experiments (2005)

Moulder, Robert, Filen, Jan-Jonas, Salmi, Jussi, Katajamaa, Mikko, Nevalainen, Olli, Oresic, Matej, ...

The options available for processing quantitative data from isotope coded affinity tag (ICAT) experiments have mostly been confined to software specific to the instrument of acquisition. However,...

Medroxyprogesterone improves nocturnal breathing in postmenopausal women with chronic obstructive pulmonary disease (2005)

Saaresranta, Tarja, Aittokallio, Tero, Utriainen, Karri, Polo, Olli

Abstract Background Progestins as respiratory stimulants in chronic obstructive pulmonary disease (COPD) have been investigated in males and during wakefulness. However, sleep and gender may...

On the Robustness of Fluorescence Fingerprinting of Plants (2005)

Codrea, Marius C., Aittokallio, Tero, Keränen, Mika, Tyystjärvi, Esa, Nevalainen, Olli S.

In the present work, we study the effect of temporal changes on the identification accuracy in fluorescence fingerprinting of plants. Here, the time series comprises consecutive datasets (chlorophyll...

Integrating probe-level expression changes across generations of Affymetrix arrays." Nucleic Acids Research 33(22): e193 (2005)

Laura L. Elo, Leo Lahti, Heli Skottman, Minna Kyläniemi, Riitta Lahesmaa, Tero Aittokallio

studies are of practical interest for minimizing the number There is an urgent need for bioinformatic methods that allow integrative analysis of multiple microarray datasets.While...

BIOINFORMATICS (2005)

Johannes Tuikkala, Laura Elo, Olli S. Nevalainen, Tero Aittokallio

Improving missing value estimation in microarray data with gene ontology

Integrating probe-level expression changes across generations of Affymetrix arrays (2005)

Elo, Laura L., Lahti, Leo, Skottman, Heli, Kyläniemi, Minna, Lahesmaa, Riitta, Aittokallio, Tero

There is an urgent need for bioinformatic methods that allow integrative analysis of multiple microarray data sets. While previous studies have mainly concentrated on reproducibility of gene...

Quality classification of tandem mass spectrometry data (2005)

Salmi, Jussi, Moulder, Robert, Filén, Jan-Jonas, Nevalainen, Olli S., Nyman, Tuula A., Lahesmaa, Riitta, ...

Motivation: Peptide identification by tandem mass spectrometry is an important tool in proteomic research. Powerful identification programs exist, such as SEQUEST, ProICAT and Mascot, which can...

Improving missing value estimation in microarray data with gene ontology (2005)

Tuikkala, Johannes, Elo, Laura, Nevalainen, Olli S., Aittokallio, Tero

Motivation: Gene expression microarray experiments produce data sets with frequent missing expression values. Accurate estimation of missing values is an important prerequisite for efficient data...

Correcting Distortions in 2D Gels - A Survey (2004)

Salmi, Jussi, Aittokallio, Tero, Nyman, Tuula A., Nevalainen, Olli S.

Two-dimensional electrophoresis (2-DE) provides a rapid means for separating thousands of proteins from cell and tissue samples in one run. Although this powerful research tool has been...

Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment (2004)

Ahola, Virpi, Aittokallio, Tero, Uusipaikka, Esa, Vihinen, Mauno

The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or...

Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment (2004)

Ahola, Virpi, Aittokallio, Tero, Uusipaikka, Esa, Vihinen, Mauno

The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or...

Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment (2004)

Ahola, Virpi, Aittokallio, Tero, Uusipaikka, Esa, Vihinen, Mauno

The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or...

Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment (2004)

Ahola, Virpi, Aittokallio, Tero, Uusipaikka, Esa, Vihinen, Mauno

The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or...

Inspiratory Flow Shape Clustering (IFSC): An Automated Method to Monitor Upper Airway Performance During Sleep (2003)

Aittokallio, Tero, Malminen, Jani S., Pahikkala, Tapio, Polo, Olli, Nevalainen, Olli S.

An automated method for monitoring the performance of upper airway during sleep is described. The method assesses the upper airway airflow dynamics based on the clusters of inspiratory flow shapes...

Feature Learning with a Genetic Algorithm for Fluorescence Fingerprinting of Plant Species (2003)

Codrea, Marius Cosmin, Aittokallio, Tero, Keränen, Mika, Tyystjärvi, Esa, Nevalainen, Olli S.

Proper feature analysis facilitates recognition by focusing the process to those characteristics of observed data that carry the most significant information for the given classification task. In...

On the Computational Analysis of Gene Expression Microarray Data (2003)

Aittokallio, Tero, Kurki, Markus, Nikula, Tuomas, West, Anne, Lahesmaa, Riitta, Nevalainen, Olli

Microarray analysis has become a widely used method for generating gene expression data on a genomic scale. DNA microarrays have been enthusiastically applied in many fields of biological research,...

Efficient estimation of emission probabilities in profile hidden Markov models (2003)

Ahola, Virpi, Aittokallio, Tero, Uusipaikka, Esa, Vihinen, Mauno

Motivation: Profile hidden Markov models provide a sensitive method for performing sequence database search and aligning multiple sequences. One of the drawbacks of the hidden Markov model is that...

Feature Learning with a Genetic Algorithm for Fluorescence Fingerprinting of Plant Species (2002)

Codrea, Marius, Aittokallio, Tero, Keränen, Mika, Tyystjärvi, Esa, Nevalainen, Olli

It is known that proper feature analysis facilitates the recognition process by including only those characteristics of observed data that carry the most significant information for the given...

Automated Detection of Differentially Expressed Fragments in mRNA Differential Display (2000)

Aittokallio, Tero, Nevalainen, Olli, Ojala, Pekka, Nevalainen, Timo J.

We present a novel method for the automated detection of fragments showing dissimilar expression in mRNA differential display. The analysis is based on aligning the numerical electrophoretic lane...

Testing for Periodicity in Signals: An Application to Detect Partial Upper Airway Obstruction during Sleep (2000)

Aittokallio, Tero, Gyllenberg, Mats, Nevalainen, Olli, Polo, Olli

A simple method for detecting periodic components of unknown periodicity in a signal is presented. The method is based on spectral decomposition of signal using orthonormal functions. Traditionally,...

Computation of Restricted Maximum-penalized-likelihood Estimates in Hidden Markov Models (2000)

Aittokallio, Tero, Nevalainen, Olli, Tolvi, Jussi, Lertola, Kalle, Uusipaikka, Esa

The maximum-penalized-likelihood estimation for hidden Markov models with general observation densities is described. All statistical inference, including the model estimation, testing, and...

Detection of High-frequency Respiratory Movements During Sleep (1999)

Aittokallio, Tero, Gyllenberg, Mats, Järvi, Jaakko, Polo, Olli, Nevalainen, Olli

Sleep-related breathing disorders are common in adults and they have a significant impact on health and safety. In previous sleep studies it has come evident that many important breathing disorders...

A Model of a Snorer's Upper Airway (1999)

Aittokallio, Tero, Gyllenberg, Mats, Polo, Olli

http://www.tucs.fi/Publications/techreports/TR266.php

Likelihood based statistical inference in hidden markov models (1999)

Tero Aittokallio, Virpi Ahola, Esa Uusipaikka

The hidden Markov model (HMM) is one type of stochastic signal model which is widely used in modeling and classication problems. Yet the more advanced statistical inference in this model has been...

Integrating probe-level expression changes across generations of Affymetrix arrays

Elo, Laura L., Lahti, Leo, Skottman, Heli, Kyläniemi, Minna, Lahesmaa, Riitta, Aittokallio, Tero

There is an urgent need for bioinformatic methods that allow integrative analysis of multiple microarray data sets. While previous studies have mainly concentrated on reproducibility of gene...

Integrating probe-level expression changes across generations of Affymetrix arrays

Elo, Laura L., Lahti, Leo, Skottman, Heli, Kyläniemi, Minna, Lahesmaa, Riitta, Aittokallio, Tero

There is an urgent need for bioinformatic methods that allow integrative analysis of multiple microarray data sets. While previous studies have mainly concentrated on reproducibility of gene...

Statistical Methods for Identifying Conserved Residues in Multiple Sequence Alignment

Virpi Ahola, Tero Aittokallio, Esa Uusipaikka, Mauno Vihinen

The assessment of residue conservation in a multiple sequence alignment is a central issue in bioinformatics. Conserved residues and regions are used to determine structural and functional motifs or...

Predicting Quantitative Genetic Interactions by Means of Sequential Matrix Approximation

Järvinen, Aki P., Hiissa, Jukka, Elo, Laura L., Aittokallio, Tero

Despite the emerging experimental techniques for perturbing multiple genes and measuring their quantitative phenotypic effects, genetic interactions have remained extremely difficult to predict on a...

Probe-level estimation improves the detection of differential splicing in Affymetrix exon array studies

Laajala, Essi, Aittokallio, Tero, Lahesmaa, Riitta, Elo, Laura L

A novel statistical procedure is presented that uses probe-level information on Affymetrix exon arrays to detect differential splicing.

Genoscape: a Cytoscape plug-in to automate the retrieval and integration of gene expression data and molecular networks

Clément-Ziza, Mathieu, Malabat, Christophe, Weber, Christian, Moszer, Ivan, Aittokallio, Tero, Letondal, Catherine, ...

Summary: Genoscape is an open-source Cytoscape plug-in that visually integrates gene expression data sets from GenoScript, a transcriptomic database, and KEGG pathways into Cytoscape networks. The...