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1.
Cent Eur J Public Health ; 26(4): 265-271, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30660136

ABSTRACT

OBJECTIVE: The marine n-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) exert numerous beneficial effects on health, but their potency to defend against development of peripheral insulin resistance of healthy person with overweight remains poorly characterized. We aimed to evaluate the effect of a combination intervention using EPA + DHA and the lifestyle modification (LSM) in women with overweight. METHOD: In a parallel-group, three-arm, randomized trial (UMIN Clinical Trials Registry - R000031131), 34 women were assigned to a 12-week-intervention using corn oil (1.5 g/day; placebo); LSM and corn oil (1.5 g/day; LSM); or LSM and EPA + DHA concentrate (1.5 g/day, containing ~ 0.6 g EPA + DHA; LSM & n-3). At baseline and after intervention, anthropometric measurements including bioelectrical impedance analysis, spiroergometry, 24-hours dietary recall, and various metabolic markers, adiponectin and cytokines were evaluated in serum using standard procedures. Data from 29 women were used for the final evaluation. Wilcoxon two-sided rank-sum test was used to inspect the differences between LSM and LSM & n-3, and placebo groups, with a p-value of ≤ 0.05. All computations were performed with MATLAB Statistics Toolbox. RESULTS: In comparison with placebo, LSM and LSM & n-3 decreased body weight, waist circumference, and body fat, and increased VO2max/kg. LSM & n-3 increased adiponectin levels in comparison to LSM. Fasting insulin, IL8, and cholesterol were decreased by LSM, but were unchanged by LSM & n-3. IL6 was not affected in LSM & n-3, while it was increased in LSM. Other inflammatory markers, as well as leptin, LIF, follistatin, BDNF, and fasting triacylglycerol were not significantly affected by any of the interventions. CONCLUSION: Besides preventing a modest negative effect of LSM on IL6 and adiponectin level, the combination of LSM and EPA + DHA supplementation could be probably used to improve the functional capacity of adipose tissue in women with overweight.


Subject(s)
Dietary Supplements , Docosahexaenoic Acids/therapeutic use , Eicosapentaenoic Acid/therapeutic use , Healthy Lifestyle , Overweight/therapy , Female , Humans , Treatment Outcome
2.
Heliyon ; 10(15): e34792, 2024 Aug 15.
Article in English | MEDLINE | ID: mdl-39144957

ABSTRACT

The rapid development in the field of electric vehicles requires a careful evaluation of the design process. The presence of a simulation model of the electric vehicle can effectively detect many faulty areas during the development process without risks. The MATLAB and Simulink environment is considered one of the most important tools used in the simulation process. In this paper, we will present the model of electric car used for transporting postal parcels (postal cars). The model includes simulating the operation of a permanent magnet synchronous electric motor. We will assume that the car is moving according to a driving cycle. The results will show the torque forces required to achieve the required speed. We will further calculate the traction and the resistance forces during the driving cycle and the engine efficiency in addition. Perhaps the most important problem facing electric car designers is calculating the amount of energy consumed from the battery or hydrogen fuel, and this is what was achieved as the result of the simulation process in this research. In the end, use one of the artificial intelligence tools (fuzzy controller) to improve battery life by providing the electric car driver with an alert system that will increase the ability to monitor the battery condition and thus increase battery life. The benefit of this paper emerges in realizing the importance of modeling and using simulation using artificial intelligence in developing the design of the electric car, specially the electric motor and battery size, and thus achieving one of the most important goals of the United Nations of preserving the environment and reducing carbon emissions.

3.
Article in English | MEDLINE | ID: mdl-36628561

ABSTRACT

AIM: We present two cases with clearly discrepant results of clinical examination and cardiac troponin I (cTnI) and cardiac troponin T (cTnT) concentrations. In similar cases with discrepant results, the possibility of interference should be considered. METHODS: Due to the suspicion of the presence of macrotroponin I in both of the presented cases, the patients were invited to our laboratory and both cTnI (Architect i1000, Abbott) and cTnT (Cobas 8000, Roche) concentrations were analysed. The samples were treated by preincubation in a heterophilic antibodies blocking tube (HBT) and analysed. Precipitation with polyethylene glycol solution (PEG) and molecular weight separation by gel filtration on Sephadex G100 was performed and concentrations of cTnI were analysed. RESULTS: In the same blood sample, the cTnT and cTnI concentrations were 7 and 1782 ng/L, respectively, in Case 1, and 6 and 96 ng/L, respectively, in Case 2. Incubation of samples in HBT had no significant effect. CTnI concentrations after precipitation with PEG - presented as the percentage of initial concentrations - were 7.4% in Case 1 (and 26.8% in the control sample) and 1.4% in Case 2 (and 56.0% in the control sample). These results indicate a significant decrease in both cases, supporting presence of macrotroponin I. Finally, analyses of cTnI concentrations after gel filtration also supported the presence of macrotroponin I. CONCLUSION: The present cases show that the presence of macrotroponin can lead to unnecessary investigation of the patient. When the possibility of interference is suspected, cooperation with laboratory staff to help with interpretation or to perform more detailed analysis is crucial.

4.
Sci Data ; 6(1): 46, 2019 05 02.
Article in English | MEDLINE | ID: mdl-31048742

ABSTRACT

The large amount of existing nanomaterials demands rapid and reliable methods for testing their potential toxicological effect on human health, preferably by means of relevant in vitro techniques in order to reduce testing on animals. Combining high throughput workflows with automated high content imaging techniques allows deriving much more information from cell-based assays than the typical readouts (i.e. one measurement per well) with optical plate-readers. We present here a dataset including data based on a maximum of 14 different read outs (including viable cell count, cell membrane permeability, apoptotic cell death, mitochondrial membrane potential and steatosis) of the human hepatoma HepaRG cell line treated with a large set of nanomaterials, coatings and supernatants at different concentrations. The database, given its size, can be utilized in the development of in silico hazard assessment and prediction tools or can be combined with toxicity results from other in vitro test systems.


Subject(s)
Databases, Factual , Nanostructures/toxicity , Apoptosis/drug effects , Carcinoma, Hepatocellular/pathology , Cell Count , Cell Line, Tumor , Cell Membrane Permeability/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Humans , Liver Neoplasms/pathology , Membrane Potential, Mitochondrial/drug effects
5.
J Med Biochem ; 37(3): 364-372, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30598634

ABSTRACT

BACKGROUND: The aim of this study was to examine high-sensitivity troponin T and I (hsTnT and hsTnI) after a treadmill run under laboratory conditions and to find a possible connection with echocardiographic, laboratory and other assessed parameters. METHODS: Nineteen trained men underwent a standardized 2-hour-long treadmill run. Concentrations of hsTnT and hsTnI were assessed before the run, 60, 120 and 180 minutes after the start and 24 hours after the run. Changes in troponins were tested using non-parametric analysis of variance (ANOVA). The multiple linear regression model was used to find the explanatory variables for hsTnT and hsTnI changes. Values of troponins were evaluated using the 0h/1h algorithm. RESULTS: Changes in hsTnT and hsTnI levels were statistically significant (p<0.0001 and p<0.0001, respectively). In a multiple regression model (adjusted R2: 0.60, p=0.005 for hsTnT and adjusted R2: 0.60, p=0.005 for hsTnI), changes in both troponins can be explained by relative left wall thickness (LV), training volume, body temperature after the run and creatinine changes. According to the 0h/1h algorithm, none of the runners was evaluated as negative. CONCLUSIONS: Relative LV wall thickness, creatinine changes, training volume and body temperature after the run can predict changes in hsTnT and hsTnI levels. When medical attention is needed after physical exercise, hsTn levels should be tested only when clinical suspicion and the patient's history indicate a high probability of myocardial damage.

6.
Oncogene ; 24(29): 4672-87, 2005 Jul 07.
Article in English | MEDLINE | ID: mdl-15940270

ABSTRACT

Tumors of low malignant potential (LMP) represent 20% of epithelial ovarian cancers (EOCs) and are associated with a better prognosis than the invasive tumors (TOV). Defining the relationship between LMPs and TOVs remains an important goal towards understanding the molecular pathways that contribute to prognosis, as well as providing molecular markers, for these EOCs. To this end, DNA microarray analyses were performed either in a primary culture or a tumor tissue model system and selected candidate genes showing a distinctive expression profile between LMPs and TOVs were identified using a class prediction approach based on three statistical methods of analysis. Both model systems appear relevant as candidate genes identified by either model allowed the proper reclassification of samples as either LMPs or TOVs. Selected candidate genes (CAS, CCNE1, LGALS8, ITGbeta3, ATP1B1, FLIP, KRT7 and KRT19) were validated by real-time quantitative PCR analysis and show differential expression between LMPs and TOVs. Immunohistochemistry analyses showed that the two tumor classes were distinguishable by their expression of CAS, TNFR1A, FLIP, CKS1 and CCNE1. These results define signature patterns for gene expression of LMPs and TOVs and identify gene candidates that warrant further study to deepen our understanding of the biology of EOC.


Subject(s)
Gene Expression Profiling , Genetic Markers , Neoplasm Invasiveness , Oligonucleotide Array Sequence Analysis , Ovarian Neoplasms/genetics , Ovarian Neoplasms/pathology , Diagnosis, Differential , Female , Humans , Polymerase Chain Reaction , Prognosis , Tumor Cells, Cultured
7.
Physiol Genomics ; 25(2): 179-93, 2006 Apr 13.
Article in English | MEDLINE | ID: mdl-16418321

ABSTRACT

Cystic fibrosis (CF) is caused by a defect in the CF transmembrane conductance regulator (CFTR) protein that functions as a chloride channel. Dysfunction of the CFTR protein results in salty sweat, pancreatic insufficiency, intestinal obstruction, male infertility, and severe pulmonary disease. Most of the morbidity and mortality of CF patients results from pulmonary complications. Differences in susceptibility to bacterial infection and variable degree of CF lung disease among CF patients remain unexplained. Many phenotypic expressions of the disease do not directly correlate with the type of mutation in the Cftr gene. Using a unique CF mouse model that mimics aspects of human CF lung disease, we analyzed the differential gene expression pattern between the normal lungs of wild-type mice (WT) and the affected lungs of CFTR knockout mice (KO). Using microarray analysis followed by quantitation of candidate gene mRNA and protein expression, we identified many interesting genes involved in the development of CF lung disease in mice. These findings point to distinct mechanisms of gene expression regulation between mice with CF and control mice.


Subject(s)
Cystic Fibrosis/metabolism , Gene Expression Regulation , Lung/metabolism , Pneumonia, Bacterial/metabolism , Pseudomonas Infections/metabolism , Animals , Cystic Fibrosis/genetics , Cystic Fibrosis/pathology , Disease Models, Animal , Female , Immunoglobulin G/genetics , Immunoglobulin G/metabolism , Lung/pathology , Male , Matrix Metalloproteinase 9/genetics , Matrix Metalloproteinase 9/metabolism , Mice , Mice, Inbred CFTR , Oligonucleotide Array Sequence Analysis/methods , Pneumonia, Bacterial/genetics , Pneumonia, Bacterial/pathology , Pseudomonas Infections/genetics , Pseudomonas Infections/pathology , RNA, Messenger/metabolism , Reproducibility of Results , Secretory Leukocyte Peptidase Inhibitor/genetics , Secretory Leukocyte Peptidase Inhibitor/metabolism
8.
Chemosphere ; 60(9): 1197-202, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16018889

ABSTRACT

Microbial degradation of two diastereoisomeric forms 2 and 3 of a selected juvenoid (insect juvenile hormone bioanalog), ethyl N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate was studied and the degradation products analyzed. Degradation experiments were performed using simple modeling under laboratory conditions. A Candida sp. strain T1, isolated from soil, was chosen as a biodegradation species. Radiolabeling of the studied compounds 2 and 3 was used in combination with radio-HPLC and MS analysis to increase the limits of detection, monitoring and isolation of trace quantities of the products of degradation and/or transformation. Resulting from the microbial processes using 2 or 3 as source compounds, three identical products (4-6) of their biodegradation were produced. Compound 2 also afforded two additional products (7, 8). Radio-HPLC analysis and separation, and subsequent MS analysis of the degradation mixtures resulted in identification of the degradation products. The degree and the rate of biodegradation of 2 and 3 were analyzed after 1, 3 and 7 days from the beginning of the experiment.


Subject(s)
Carbamates/metabolism , Daphnia/metabolism , Juvenile Hormones/metabolism , Soil Microbiology , Animals , Biodegradation, Environmental , Biotransformation , Carbamates/chemistry , Carbamates/toxicity , Chromatography, High Pressure Liquid/methods , Insecta , Isotope Labeling , Juvenile Hormones/chemistry , Juvenile Hormones/toxicity , Mass Spectrometry/methods , Stereoisomerism , Time Factors
9.
Anticancer Res ; 35(6): 3537-41, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26026122

ABSTRACT

AIM: The aim of the present study was to evaluate the usefulness of four interleukins (IL-2, IL-6, IL-8 and IL-10) for melanoma detection and correlate these interleukins with sentinel node metastasis positivity. PATIENTS AND METHODS: A group of 236 persons was assessed: 175 patients with melanomas and 61 healthy persons. Melanoma patients were divided to four groups according to Breslow score. We determined IL-2, IL-6, IL-8 and IL-10 in each plasma sample. Interleukin plasma levels were assayed using a Human Cytokine Milliplex Map kit. Measurements were performed using the Bio-Plex MAGPIX Multiplex Reader. Plasma samples were collected prior to surgery or any other form of treatment. All melanoma diagnoses were histologically verified. RESULTS: We compared interleukin plasma levels in the healthy group and plasma levels in each Breslow score stage. In the first Breslow score stage, IL-2 (p<0.0001), IL-6 (p=0.0004) and IL-10 (p<0.0001) were positive. In the second Breslow score, stage IL-2 (p<0.0001), IL-6 (p<0.0001), IL-8 (p=0.0017) and IL-10 (p<0.0001) were positive. By comparing the group of positive and negative sentinel node metastasis, we observed a statistically significant difference in two interleukins: The median of IL-2 levels in the negative group was 5.88 pg/ml compared to 32.57 pg/ml in the positive group (p=0.0005). The median of IL-6 levels in the negative group was 4.80 pg/ml compared to 32.02 pg/ml in the positive group (p=0.0048). CONCLUSION: Interleukins IL-2, IL-6 and IL-10 are promising biomarkers of early-stage melanoma. IL-2 and IL-6 appear to be prognostic biomarkers.


Subject(s)
Interleukin-10/blood , Interleukin-2/blood , Interleukin-6/blood , Interleukin-8/blood , Melanoma/blood , Adolescent , Adult , Aged , Aged, 80 and over , Early Detection of Cancer , Female , Humans , Lymphatic Metastasis , Male , Melanoma/pathology , Middle Aged , Neoplasm Staging , Prognosis , Sentinel Lymph Node Biopsy
10.
Anticancer Res ; 35(9): 4855-7, 2015 Sep.
Article in English | MEDLINE | ID: mdl-26254378

ABSTRACT

AIM: To evaluate changes in the serum levels of prostate specific antigen (PSA), %free PSA and -2proPSA biomarkers, and prostate health index (PHI) in the diagnostic algorithm of early prostate cancer. PATIENTS AND METHODS: The Immunoanalytical Laboratory of the University Hospital in Pilsen examined sera from 263 patients being treated at the Hospital's Urology Department with suspected prostate cancer who had undergone biopsies and were divided into a benign and malignant group. The monitored biomarkers were measured using chemiluminescence. All statistical analyses were calculated using the SAS software. RESULTS: We found statistically significantly increased levels of -2proPSA, PHI and PSA and decreased levels of %freePSA in patients diagnosed with prostate cancer by prostate biopsy vs. patients with benign prostatic hypertrophy (median values: -2proPSA: 16 vs. 21 ng/l, PHI: 35 vs. 62, total PSA: 7.2 vs. 7.7 µg/l and %free PSA: 16.7 vs. 11.7%). Receiver operating characteristic curves showed the best performance for PHI compared to other markers. CONCLUSION: The assessment of -2proPSA and the calculation of PHI appear to be of great benefit for a more accurate differential diagnosis of benign hyperplasia and prostate cancer.


Subject(s)
Prostate/pathology , Prostatic Neoplasms/diagnosis , Aged , Aged, 80 and over , Area Under Curve , Biomarkers, Tumor/blood , Early Detection of Cancer , Humans , Male , Middle Aged , Prostate-Specific Antigen/blood , Prostatic Neoplasms/blood , ROC Curve , Sensitivity and Specificity
11.
J Chromatogr A ; 1032(1-2): 59-63, 2004 Apr 02.
Article in English | MEDLINE | ID: mdl-15065777

ABSTRACT

The described radiochromatographic method permits fast and high-sensitivity monitoring of soil biodegradation products of an insect growth regulator for its environmental risk assessment. We analyzed and compared two diastereoisomers of ethyl N-(2-(4-[(2-hydroxycyclohexyl) methyl]phenoxy)ethyl)carbamate, namely its cis-(1S,2S) isomer JN-W330 and a trans-(1R,2S) isomer JN-W331. Microbial conversion of the cis-isomer to the trans-isomer was proved by mass spectrometry analyzer. Among the chromatographic columns tested, the best separation was found with a 125 mm x 4 mm i.d. column packed with Supersphere 100 RP-C18, 5 microm and an acetonitrile-water gradient. The detection limit for the both isomers was in the range of 120-250 Bq (0.3-0.8 ng) at a concentration of 2 ng/ml with radiometric detection. The calibration curves for standard solutions were linear in the range of 150Bq-150kBq (r = 0.996). The method enabled us to compare the analyzed juvenoids with biologically active oostatic peptides in terms of their environmental safety.


Subject(s)
Chromatography, High Pressure Liquid/methods , Juvenile Hormones/toxicity , Radiometry/methods , Animals , Juvenile Hormones/chemistry , Stereoisomerism
12.
Chemosphere ; 52(1): 151-9, 2003 Jul.
Article in English | MEDLINE | ID: mdl-12729698

ABSTRACT

Juvenoids are efficient pesticides with relatively low toxicity to humans. However, few studies have evaluated the effect of degradation by soil microorganisms on their toxicity. The effects of bacterial, fungal and yeast isolates on aerobic decomposition of ethyl N-[2-[4-(2,2-ethylenedioxy-1-cyclohexylmethyl)phenoxy]ethyl] carbamate during eight weeks were determined. The effect of different concentration of glucose on their degradation activity is also analyzed.


Subject(s)
Carbamates/metabolism , Soil Microbiology , Soil Pollutants/metabolism , Bacteria, Aerobic , Biodegradation, Environmental , Fungi , Glucose , Yeasts
13.
Chemosphere ; 46(2): 209-17, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11827277

ABSTRACT

Juvenoids are biologically active compounds, of relatively low toxicity to humans, that efficiently inhibit the fertility of insects. However, little attention has been paid to the stability and toxicity of products that may be generated by their biodegradation in the ecosystem. This study describes a simple comparison of the toxicity of the active compound and its degradation products generated by aerobic soil microbial isolates. Surprisingly we have found that toxicity of a biologically active carbamate juvenoid N-[2-[4-(2,2-ethylenedioxy-1-cyclohexylmethyl)-phenoxylethyl]carbamate (W328) was comparable with that of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT). The toxic effect was evaluated using the determination of the ATP/ADP content and viability of HeLa S3 cells exposed to various concentrations of the chemicals tested for various durations. DDT was used as a reference compound. Its toxicity was compared with two juvenile hormone analogs. The original compound, W328, was found to be the most toxic. The major product (W329) generated both by yeast isolates and the mixture of moulds lost its activity on reproduction of the tested insect. Its toxicity towards human cells was also decreased. Another two W328 degradation HPLC fractions exhibited significantly reduced toxicity compared to W328.


Subject(s)
Carbamates , Insecticides/toxicity , Adenosine Diphosphate/analysis , Adenosine Triphosphate/analysis , Animals , Biodegradation, Environmental , Biomarkers , Cell Survival , HeLa Cells , Humans , Insecta , Insecticides/metabolism , Juvenile Hormones , Reproduction/drug effects , Yeasts
14.
Article in English | MEDLINE | ID: mdl-21048814

ABSTRACT

BACKGROUND: Ileus states are serious conditions that may lead to pathophysiological changes which in turn can result in perforation of bowel, peritonitis, sepsis or death. Our paper discusses paralytic ileus states, which can be caused by psychopharmaceutics with anticholinergic side effects. METHODS AND RESULTS: Retrospective analysis of cases of paralytic ileus in mentally ill patients admitted to Mental Hospital Kromeriz. CONCLUSION: Although some old psychopharmacs have a much higher potential for anticholinergic side effects than the new ones, there are still some of the new modern antipsychotics which also have anticholinergic side effects which could cause paralytic ileus. Both psychiatrists and surgeons should pay attention to atypical or changed signs of ileus states in mentally ill patients and should be aware of the confounding factors which could make the diagnosis of ileus difficult in mentally ill patients.


Subject(s)
Intestinal Pseudo-Obstruction/chemically induced , Psychotropic Drugs/adverse effects , Female , Humans , Intestinal Pseudo-Obstruction/diagnosis , Male , Mental Disorders/drug therapy , Middle Aged
15.
J Agric Food Chem ; 56(15): 6604-8, 2008 Aug 13.
Article in English | MEDLINE | ID: mdl-18597472

ABSTRACT

Two bacteria were isolated from sand RQ30, characterized as Bacillus simplex and Bacillus sp. strain 05 (GenBank EU399813 ), and were used as biocatalysts for a hydrolytic assay of stability of the cis or trans isomers of ethyl N-{2-{4-{[2-(butanoyl)oxycyclohexyl]methyl}phenoxy}ethyl}carbamate, which are among insect hormonogen substances (juvenogens). The stability tests were performed using simple modeling under laboratory conditions. The structures of the products were assigned as ethyl (1 R,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate and ethyl (1 S,2 R)- N-{2-{4-[(2-hydroxycyclohexyl)methyl]phenoxy}ethyl}carbamate on the basis of (1)H and (13)C NMR, IR, and FAB-MS analyses.


Subject(s)
Bacillus/metabolism , Juvenile Hormones/chemistry , Juvenile Hormones/metabolism , Soil Microbiology , Carbamates/chemistry , Carbamates/metabolism , Cyclohexanols/chemistry , Cyclohexanols/metabolism , Hydrolysis , Stereoisomerism
17.
Biol Direct ; 1: 18, 2006 Jun 20.
Article in English | MEDLINE | ID: mdl-16787528

ABSTRACT

BACKGROUND: Gene expression microarray technology continues to evolve and its use has expanded into all areas of biology. However, the high dimensionality of the data makes analysis a difficult challenge. Evaluating measurements and estimating the significance of the observed differences among samples remain important issues that must be addressed for each technology platform. In this work we use a consecutive sampling method to characterize the dispersion patterns of data generated from Illumina fiberoptic bead-based oligonucleotide arrays. RESULTS: To describe general properties of the dispersion we used a linear function SD = a + bY(mean), approximating the standard deviation across arrays (Y(mean) is the mean expression of a given consecutive sample). First we examined three levels of variability: 1) same cell culture, same reverse transcription, duplicate hybridizations; 2) same cell culture, reverse transcription replicates; 3) parallel cultures. Each higher level is expected to introduce a new source of variability. We observed minor differences in the constant term: the mean values are 3.5, 3.1 and 3.5, respectively. However, the mean coefficient b increased from 0.045 to 0.147 and 0.133. We compared the coefficients derived from the consecutive sampling to those obtained from the standard deviation of individual gene expressions and found them in good agreement. In the second experiment samples we detected 11 genes with systematically different expressions between the experiment samples treated with glucose oxidase and controls and corroborated the selection using the Mann-Whitney and other tests. We also compared the consecutive sampling and coincidence method to t-test: the average percentage of consistency was above 80 for the former and below 50 for the latter. CONCLUSION: Our results indicate that the consecutive sampling method and standard deviation function provide a convenient description of the overall dispersion of Illumina arrays. We observed that the constant term of the standard deviation function is at average approximately the same for duplicate hybridization as for the assays with additional sources of variability. Furthermore, among the genes affected by glucose oxidase treatment we identified 6 genes in oxidative stress pathways and 5 genes involved in DNA repair. Finally, we noted that the consecutive sampling and coincidence test provide, under given conditions, more consistent results than the t-test. REVIEWERS: This article was reviewed by Alexander Karpikov (nominated by Mark Gerstein), Jordan King and Eugene V. Koonin.

18.
Biol Direct ; 1: 27, 2006 Sep 07.
Article in English | MEDLINE | ID: mdl-16959036

ABSTRACT

BACKGROUND: DNA microarrays are a powerful technology that can provide a wealth of gene expression data for disease studies, drug development, and a wide scope of other investigations. Because of the large volume and inherent variability of DNA microarray data, many new statistical methods have been developed for evaluating the significance of the observed differences in gene expression. However, until now little attention has been given to the characterization of dispersion of DNA microarray data. RESULTS: Here we examine the expression data obtained from 682 Affymetrix GeneChips with 22 different types and we demonstrate that the Gaussian (normal) frequency distribution is characteristic for the variability of gene expression values. However, typically 5 to 15% of the samples deviate from normality. Furthermore, it is shown that the frequency distributions of the difference of expression in subsets of ordered, consecutive pairs of genes (consecutive samples) in pair-wise comparisons of replicate experiments are also normal. We describe a consecutive sampling method, which is employed to calculate the characteristic function approximating standard deviation and show that the standard deviation derived from the consecutive samples is equivalent to the standard deviation obtained from individual genes. Finally, we determine the boundaries of probability intervals and demonstrate that the coefficients defining the intervals are independent of sample characteristics, variability of data, laboratory conditions and type of chips. These coefficients are very closely correlated with Student's t-distribution. CONCLUSION: In this study we ascertained that the non-systematic variations possess Gaussian distribution, determined the probability intervals and demonstrated that the K(alpha) coefficients defining these intervals are invariant; these coefficients offer a convenient universal measure of dispersion of data. The fact that the K(alpha) distributions are so close to t-distribution and independent of conditions and type of arrays suggests that the quantitative data provided by Affymetrix technology give "true" representation of physical processes, involved in measurement of RNA abundance. REVIEWERS: This article was reviewed by Yoav Gilad (nominated by Doron Lancet), Sach Mukherjee (nominated by Sandrine Dudoit) and Amir Niknejad and Shmuel Friedland (nominated by Neil Smalheiser).

19.
Genomics ; 79(1): 104-13, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11827463

ABSTRACT

Large-scale gene expression measurement techniques provide a unique opportunity to gain insight into biological processes under normal and pathological conditions. To interpret the changes in expression profiles for thousands of genes, we face the nontrivial problem of understanding the significance of these changes. In practice, the sources of background variability in expression data can be divided into three categories: technical, physiological, and sampling. To assess the relative importance of these sources of background variation, we generated replicate gene expression profiles on high-density Affymetrix GeneChip oligonucleotide arrays, using either identical RNA samples or RNA samples obtained under similar biological states. We derived a novel measure of dispersion in two-way comparisons, using a linear characteristic function. When comparing expression profiles from replicate tests using the same RNA sample (a test for technical variability), we observed a level of dispersion similar to the pattern obtained with RNA samples from replicate cultures of the same cell line (a test for physiological variability). On the other hand, a higher level of dispersion was observed when tissue samples of different animals were compared (an example of sampling variability). This implies that, in experiments in which samples from different subjects are used, the variation induced by the stimulus may be masked by non-stimuli-related differences in the subjects' biological state. These analyses underscore the need for replica experiments to reliably interpret large-scale expression data sets, even with simple microarray experiments.


Subject(s)
Gene Expression Profiling , Genetic Variation , Oligonucleotide Array Sequence Analysis/statistics & numerical data , Research Design/trends , Animals , Humans , Mice , RNA , Reproducibility of Results , Tumor Cells, Cultured
20.
Genome Res ; 12(1): 112-21, 2002 Jan.
Article in English | MEDLINE | ID: mdl-11779836

ABSTRACT

We have investigated previously the utility of oligonucleotide expression microarray technology in an analysis of four spontaneously transformed epithelial ovarian cancer (EOC) cell lines, TOV-21G, TOV-81D, OV-90, and TOV-112D. Here, we examine the expression of 290 expressed sequence tags (ESTs) that map to human chromosome 3 in a primary culture derived from normal ovarian surface epithelium (NOSE), NOV-31, and the four spontaneously transformed EOC cell lines. One of these cell lines, OV-90, harbors a deletion of an entire chromosome 3p arm. Whereas the most aggressive cell lines (OV-90, TOV-112D, and TOV-21G) exhibited the highest levels of expression, assessed by the mean of expression values of all ESTs, OV-90 showed the lowest mean of expression of ESTs that map to the 3p arm in comparison with TOV-112D and TOV-21G. This difference in expression profile of 3p ESTs in OV-90 is also reflected in the ratio of expression of ESTs on 3p versus the 3q arm and in that the expression values of ESTs that map to 3p were more often lower than higher in OV-90 in two-way comparisons with NOV-31, TOV-21G, and TOV-112D. The loss of a 3p arm does not affect the pattern of differential expression in analyses based on the range of numeric expression values of each EST or fold differences in expression for each EST in comparison with NOV-31. However, 25 differentially expressed ESTs were identified on the basis of threefold differences in expression values between NOV-31 and any EOC cell line; and six of these ESTs were differentially expressed uniquely in OV-90. The investigation of these ESTs could facilitate the identification of novel chromosome 3 genes implicated in ovarian tumorigenesis.


Subject(s)
Chromosomes, Human, Pair 3/genetics , Gene Expression Profiling , Neoplasms, Glandular and Epithelial/genetics , Ovarian Neoplasms/genetics , Chromosome Mapping , Expressed Sequence Tags , Female , Gene Expression Profiling/methods , Gene Expression Regulation, Neoplastic/genetics , Humans , Oligonucleotide Array Sequence Analysis , Tumor Cells, Cultured
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