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1.
Biomed Khim ; 68(5): 375-382, 2022 Nov.
Article in Russian | MEDLINE | ID: mdl-36373884

ABSTRACT

The molecular profile of a tumor is associated with its histological type and can be used both to study the mechanisms of tumor progression and to diagnose it. In this work, changes in the lipid profile of a malignant breast tumor and the adjacent tissue were studied. The potential possibility of determining the histological type of the tumor by its lipid profile was evaluated. Lipid profiling was performed by reverse-phase chromato-mass-spectrometric analysis the tissue of lipid extract with identification of lipids by characteristic fragments. Potential lipid markers of the histological type of tumor were determined using the Kruskal-Wallis test. Impact of lipid markers was calculated by MetaboAnalyst. Classification models were built by support vector machines with linear kernel and 1-vs-1 architecture. Models were validated by leave-one out cross-validation. Accuracy of models based on microenvironment tissue, were 99% and 75%, accuracy of models, based on tumor tissue, were 90% and 40% for the positive ion mode and negative ion mode respectively. The lipid profile of marginal (adjacent) tissue can be used for identification histological types of breast cancer. Glycerophospholipid metabolism pathway changes were statistically significant in the adjacent tissue and tumor tissue.


Subject(s)
Breast Neoplasms , Lipidomics , Humans , Female , Breast Neoplasms/pathology , Lipids/analysis , Mass Spectrometry , Biomarkers , Tumor Microenvironment
2.
Arkh Patol ; 84(3): 5-13, 2022.
Article in Russian | MEDLINE | ID: mdl-35639838

ABSTRACT

BACKGROUND: Acute respiratory distress syndrome (ARDS) with COVID-19 has a worse prognosis than ARDS with other diseases. Mortality from ARDS with COVID-19 is 26.0 - 61.5%, and due to other causes - 35.3-37.2%. OBJECTIVE: To find of the correlation between polymorphonuclear leukocytes (PMNs), lymphocytes, and macrophages in the cellular composition of the inflammatory infiltrate at different stages and phases of diffuse alveolar damage (DAD) with COVID-19, analyzing the autopsy material. MATERIAL AND METHODS: The lung tissue of 25 patients who died from ARDS with COVID-19 without a secondary bacterial or mycotic infection, another thanatologically significant pathology of the lungs, was studied. To study the cellular composition of the inflammatory infiltrate and the dynamics of its changes a double immunohistochemical analysis of the expression of antibodies to CD15, CD3, and CD68 was used. RESULTS: The inflammatory infiltrate and intraalveolar exudate in the exudative phase of DAD was represented by 56.8% of PMNs (CD15-positive cells; hereinafter - the average value of the percentage of positive cells to the total number of cells of the inflammatory infiltrate), 6.9% - lymphocytes (CD3-positive cells) and 19.5% macrophages (CD68-positive cells). In the early stage of the proliferative phase: 14.1% PMNs, 38.7% lymphocytes and 13.5% macrophages. In the late stage of the proliferative phase: 11.3% PMNs, 14.5% lymphocytes and 39.3% macrophages. CONCLUSIONS: In the exudative phase of DAD a statistically significant predominance of PMN was revealed, which could determine the main volume of lung damage and the severity of ARDS with COVID-19. In the early stage of the proliferative phase of DAD, a statistically significant change in the composition of the inflammatory infiltrate was revealed to compare with the exudative phase: a significant decrease in the content of PMNs relative to the total number of cells in the inflammatory infiltrate; an increase in the number of lymphocytes, which is probably associated with the start of organization and repair processes. In the late stage of the proliferative phase of DAD, compared with its early stage, was revealed a statistically significant increase in the number of macrophages in ratio.


Subject(s)
COVID-19 , Respiratory Distress Syndrome , Autopsy , Humans , Lung/pathology , Pulmonary Alveoli/pathology
3.
Biomed Khim ; 68(2): 144-152, 2022 Apr.
Article in Russian | MEDLINE | ID: mdl-35485488

ABSTRACT

Research of cancer progression mechanisms and their impact on metabolism of tumor cells and tumor microenvironment cells is an important element in drug development for cancer target therapy. In this study, changes in tumor tissue and margin tissue lipid profiles, were associated with the following clinical and morphological characteristics: tumor size, cancer stage, multifocalite, tumor grade, number of lymph node metastasis, Nottingham prognostic index, total malignancy score, level of Ki67 protein. Lipid profiling was performed by reverse-phase chromato-mass spectrometry analysis of lipid tissue extract with lipid identification by characteristic fragments. In the lipid profile of tumor tissue 13 characteristic lipids were selected. Their levels significantly correlated with at least 5 clinical and morphological features. Eight of 13 belonged to phosphatidylcholines. In lipid profile of tumor microenviroment tissue 13 lipid features were selected. Their levels significantly correlated with at least 5 clinical and morphological features. Four of 13 belonged to oxidized lipids, 4 lipid features belonged to sphingomyelins, four of 13 belonged to phosphatidylethanolamines. The tumor microenvironment tissue lipid profile correlated with tumor size, cancer stage, tumor grade, number of axillary metastases, Nottingham prognostic index. The tumor tissue lipid profile correlated with tumor size, tumor grade, total malignant score, and number of axillary metastases.


Subject(s)
Breast Neoplasms , Breast Neoplasms/metabolism , Female , Humans , Lipidomics , Lymphatic Metastasis , Neoplasm Staging , Prognosis , Tumor Microenvironment
4.
Biomed Khim ; 67(1): 88-94, 2021 Jan.
Article in Russian | MEDLINE | ID: mdl-33645526

ABSTRACT

Aberrant methylation is strongly associated with development of cancer, but limited data exist on correlation between methylation and regional lymph node metastasis (RLNM). The aim of this research was to study using of methylation levels of WIF1, RASSF1A, CDO1 and MEST aberrant methylated genes in a primary breast cancer for prediction of regional lymph node metastases. We used MS-HRM (Methylation Sensitive High Resolution Melting) to assess methylation levels. The results were confirmed by pyrosequencing. The study included 66 women with LumA and 46 women with HER2- (LumB-), 22 and 26 of them had metastasis in at least one lymph node respectively. It was found that methylation levels between LumA and LumB subtypes differed significantly in genes: WIF1 (p<0.001), CDO1 (p=0.002) and MEST (p=0.033). In the Lum A subtype statistically significant differences in level of methylation of WIF1 gene between patients with metastases in RLNM and patients without metastases were found (p=0.03). Analysis of tumors longer than 2 cm in the LumA subtype, revealed an increase of statistical significance of WIF1 gene - p=0.009 (AUC (95%CI) = 0.76 (0.59-0.93)). In LumB- subtype RASSF1A, CDO1 and MEST had statistically significant differences in methylation level between groups (p=0.03, p=0.048 and p=0.045 respectively). ROC analysis showed that combining of three genes by logistic regression, AUC (95%CI) was 0.74 (0.6-0.88). Analysis of tumors longer than 2 cm, did not increase statistical significance for these genes (p=0.046; p=0.089 and p=0.076, respectively). Thus, the study of methylation in primary tumors may be useful for prediction of lymph node metastasis, as well as for better understanding of biological process inside breast cancer.


Subject(s)
Breast Neoplasms , Biomarkers, Tumor/genetics , Breast Neoplasms/genetics , DNA Methylation , Female , Humans , Lymphatic Metastasis , Phenobarbital , Receptors, Estrogen/metabolism
5.
Bull Exp Biol Med ; 170(3): 356-359, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33452990

ABSTRACT

We studied biocompatibility and bioresorption of 3D-printed polylactide and polyglycolide tissue membranes. Ultrasound microscopy and histological examination showed that membranes fabricated of a copolymer of lactic and glycolic acids in a mass ratio of 1:9 are bioresorbed and have good biocompatibility with soft tissues (connective tissue, adipose tissue, and epithelium). An important feature of the copolymer membranes, which differs them from pure polylactide membranes, is the formation of a thin fibrous capsule that did not interfere its destruction by the mechanism of hydrolytic resorption.


Subject(s)
Biocompatible Materials/chemistry , Polyesters/chemistry , Polyglycolic Acid/chemistry , Membranes, Artificial , Printing, Three-Dimensional
6.
Cancer Treat Res Commun ; 20: 100026, 2019.
Article in English | MEDLINE | ID: mdl-31255253

ABSTRACT

BACKGROUND: It is shown that each type of human malignancies has a unique set of expressed miRNAs, and tumor-specific miRNAs in biological tissues of a patient are stable. The aim of this study was to determine the differences in the expression of miRNAs in tumor tissue of invasive breast carcinoma compared to normal tissue, as well as to analyze the variable expression of miRNAs in molecular genetic subtypes of breast cancer. METHODS: We determined differences in mRNA expression in 35 biopsies of tumor tissue of various molecular genetic subtypes of breast cancer and 35 biopsies of adjacent conventionally normal breast tissue by RT-PCR in real time. We assessed the expression levels of miRNA-21, 221, 222, 155, 205, 20a , 125b and 200a. RESULTS: A significant increase in the level of expression of the oncogenic miRNA-20a (p=0.000141) and miRNA-221 (p=0.037777) in the triple negative cancer in comparison with the luminal A and luminal B/HER2/neu-negative breast cancer subtypes was established. Assessment of significance of the results was conducted using ROC analysis. For miRNA-221 AUC value was 0.772, for miRNA-20a AUC value was 0.949. The obtained results suggest the possibility of using the levels of miRNA-21, 155, 205, 125b expression in tumor tissue to assess a malignant potential of a breast carcinoma. The levels of expression of oncogenic miRNA-221 and miRNA-20a are increased in TNBC compared with luminal A and luminal B/HER2/neu-negative breast cancer subtypes, supporting the characteristic of TNBC as the most aggressive subtype of breast cancer. MiRNA-20a is a marker of TNBC compared with luminal subtypes of breast cancer. MICRO ABSTRACT: To identify markers for breast cancer with triple-negative phenotype, we evaluated expression levels of siRNA-21, 221, 222, 155, 205, 20a, 125b, 200a and 146b in the tumor tissue of 35 patients by RT-PCR. AUC value equal to 0.949 in the ROC-analysis allows us to recommend the miRNA-20a as a marker of triple negative breast cancer to differentiate it from the luminal subtypes.


Subject(s)
Biomarkers, Tumor , Breast Neoplasms/genetics , Gene Expression Regulation, Neoplastic , MicroRNAs/genetics , Adult , Aged , Aged, 80 and over , Biopsy , Breast Neoplasms/diagnosis , Female , Gene Expression Profiling , Humans , Middle Aged , Neoplasm Grading , Neoplasm Staging , Prognosis , ROC Curve , Transcriptome , Tumor Burden
7.
Khirurgiia (Mosk) ; (12): 88-92, 2016.
Article in Russian | MEDLINE | ID: mdl-28091463

ABSTRACT

AIM: To improve the results of treatment of a widespread purulent peritonitis in children by optimizing fluid therapy includes the use of combined treatment: reamberin and remaxol. MATERIAL AND METHODS: We studied 269 patients aged 1 to 15 years with a widespread purulent peritonitis treated at the children's surgical departments in Samara from 2001 to 2015. The study group included 179 children who used the optimized infusion therapy. In the study group was allocated to 2 groups: 69 children in infusion therapy which used reamberin and 110 patients in which treatment was applied reamberin and remaxol. The surgical treatment used laparoscopic sanation of the abdomen. Comprehensive survey included a study of dynamics of the white blood cell count, leukocyte index Kalf-Caliph, erythrocyte sedimentation rate, temperature, total albumin concentration, transaminase levels. Catamnesis studied 48 patients with the definition of complex intima-media thickness in the projection of basilar, brachial and femoral arteries. RESULTS: A study compared indicators of both groups, revealed a more rapid reduction of intoxication symptomps (leukocytosis, LII, body temperature), the disappearance of enteric disease, recovery of protein-synthetic function of the liver, decrease of cytolytic and mesenchymal-inflammatory syndromes in the main group, especially in the subgroup in which treatment was included remaxol. CONCLUSION: The use of reamberin and remaxol in infusion therapy led to improvement of the results of the treatment of common purulent peritonitis in children. Study catamnesis with the study of the intima-media revealed that children undergoing widespread purulent peritonitis further develop signs of endothelial dysfunction. The developed clinical recommendations to significantly reduce the risk of developing signs of endothelial dysfunction, thereby reducing the possible appearance of vascular pathology in patients who underwent childhood widespread purulent peritonitis.


Subject(s)
Arteries/diagnostic imaging , Fluid Therapy/methods , Peritonitis/therapy , Succinates/therapeutic use , Vascular Diseases/prevention & control , Adolescent , Arteries/physiopathology , Child , Child, Preschool , Combined Modality Therapy , Endothelium, Vascular/diagnostic imaging , Humans , Infant , Laparoscopy , Peritonitis/drug therapy , Vascular Diseases/etiology
8.
Fiziol Zh (1994) ; 62(4): 12-17, 2016.
Article in Ukrainian | MEDLINE | ID: mdl-29975469

ABSTRACT

In this study, we examined the activation of natural killer(NK)-lymphocytes mediated by Toll-like receptor 3(TLR3), in the group of children with recurrent infections and the group of children with invasive bacterial infections. We examined level of CD69 (marker, of activation) expression on NK - lymphocytes after incubation with TLR3 ligand. There was a significant decrease in the level of an activation marker - 36,3±4,4% in the group of children with recurrent infections, compared with a control group of healthy children (56,5±4,9%) and the group of children with invasive bacterial infections (55,9±4,4%). Also, decreased was an activation potential of NK-lymphocytes - 24,9±L4,5% which was calculated as the difference between the percentage of CD69+ NK - lymphocytes after incubation and spontaneous value (without the addition of activator). There were no correlations between markers of TLR3 mediated activation of NK-cells and the age. Thus, the ability to activate NK - lymphocyte mediated by TLR3, independent of age and reduced in the group of children with recurrent infections. Reduced activation of NK-lymphocytes may contribute to increased susceptibility to viral infections and bacterial complications.


Subject(s)
Antigens, CD/genetics , Antigens, Differentiation, T-Lymphocyte/genetics , Bacterial Infections/immunology , Killer Cells, Natural/drug effects , Lectins, C-Type/genetics , Respiratory Tract Infections/immunology , Toll-Like Receptor 3/genetics , Adolescent , Antigens, CD/immunology , Antigens, Differentiation, T-Lymphocyte/immunology , Bacterial Infections/genetics , Bacterial Infections/microbiology , Case-Control Studies , Child , Child, Preschool , Female , Gene Expression Regulation , Humans , Infant , Killer Cells, Natural/immunology , Killer Cells, Natural/microbiology , Lectins, C-Type/immunology , Lymphocyte Activation , Male , Poly I-C/pharmacology , Primary Cell Culture , Recurrence , Respiratory Tract Infections/genetics , Respiratory Tract Infections/microbiology , Toll-Like Receptor 3/immunology
9.
Khirurgiia (Mosk) ; (7): 65-68, 2015.
Article in Russian | MEDLINE | ID: mdl-26271567

ABSTRACT

THE PURPOSE OF THE STUDY: Improving the treatment of advanced peritonitis via use in therapy antihypoxant Reamberin and hepatoprotector Remaxol, nutritional support, sanitation laparoscopic abdominal cavity. SUBJECTS: A total of 232 children aged 1 to 15 years with generalized purulent peritonitis treated at the children's surgical departments of Samara from 2001 to 2014. A study group comprised 148 patients who used the optimized pathogenetic therapy. In the study group was allocated two groups: 64 patients in the pathogenetic therapy that used antihypoxant reamberin, and 84 children in the treatment of which reamberin and hepatoprotector remaxol. All the children of the main group received nutritional support (trophic feedings), used in the surgical treatment of abdominal laparoscopic sanitation. Comprehensive survey includes the study of the dynamics of the level of white blood cells, leukocyte index on Kalf-Caliph, erythrocyte sedimentation rate, temperature, total albumin concentration, transaminase levels. RESULTS: Comparison of the studied parameters in the study and control groups, showed a more rapid decrease in the symptoms and signs of intoxication (leukocytosis, LII, body temperature), relief of enteric disease, recovery of protein-synthetic function of the liver, a decrease of cytolytic and mesenchymal-inflammatory syndrome in the study group, especially in the subgroup in which therapy was included remaxol. CONCLUSIONS: Optimization of treatment involving the application of the combined drugs--antihypoxant reamberin, hepatoprotector remaxol, nutritional support and implementation of laparoscopic abdominal sanitation led to improved results of therapy common purulent peritonitis in children.


Subject(s)
Drainage/methods , Laparoscopy/methods , Meglumine/analogs & derivatives , Nutritional Support/methods , Peritonitis/therapy , Succinates/therapeutic use , Adolescent , Child , Child, Preschool , Drug Therapy, Combination , Female , Humans , Infant , Male , Meglumine/therapeutic use , Retrospective Studies , Treatment Outcome
10.
Vopr Onkol ; 61(3): 435-8, 2015.
Article in Russian | MEDLINE | ID: mdl-26242158

ABSTRACT

It was retrospectively analyzed clinicopathological features of 529 breast cancer patients treated at the Ulyanovsk Oncology Center. Of 529 patients 235 (44.4%) had at least one positive axillary lymph node. Tumor size (p = 0,0005), histological grade (p = 0004), lymphovascular invasion (p < 0,0001), HER2-status (p = 0,014) and total score of malignancy (p < 0,0001) were significant independent predictors for lymph nodes metastases. By univariate and multivariate regression analysis it was created the graphic variant of nomogram which could predict the risk of lymph nodes metastases in breast cancer patients. An area under ROC-curve in our nomogram reached 0,737 that demonstrated high prediction level of accuracy of the developed model. Thus new nomogram is a useful tool in planning axillary surgery in breast cancer patients.


Subject(s)
Breast Neoplasms/diagnosis , Lymph Nodes/pathology , Lymphatic Metastasis/diagnosis , Nomograms , Adult , Aged , Area Under Curve , Biomarkers, Tumor/analysis , Breast Neoplasms/pathology , Female , Humans , Middle Aged , Neoplasm Grading , Neoplasm Invasiveness , Predictive Value of Tests , Prognosis , ROC Curve , Receptor, ErbB-2/analysis , Retrospective Studies , Risk Assessment , Risk Factors , Vascular Neoplasms/secondary
11.
Arkh Patol ; 77(3): 41-50, 2015.
Article in Russian | MEDLINE | ID: mdl-26226781

ABSTRACT

The paper reviews the literature on primary paratesticular tumors. It describes the classification, brief characteristics of liposarcomas and the morphological pattern of the tumor with an immunohistochemical profile. A clinical case of differentiated liposarcoma of the spermatic cord with myxoid and rhabdomyoblastic differentiation is depicted in a 61-year-old man.


Subject(s)
Liposarcoma/metabolism , Liposarcoma/pathology , Spermatic Cord/metabolism , Spermatic Cord/pathology , Testicular Neoplasms/metabolism , Testicular Neoplasms/pathology , Humans , Immunohistochemistry , Male , Middle Aged
12.
Vestn Khir Im I I Grek ; 174(6): 56-9, 2015.
Article in Russian | MEDLINE | ID: mdl-27066660

ABSTRACT

The bleeding of intraoperative period is one of the actual problem in surgery. There aren't any universal hemostatic means in spite of large variety of modern hemostatic methods. An experimental research studied the results of hemostatic activity of different forms of materials on the basis of oxidize cellulose (a gauze, a powder) as compared with their foreign analog (a hemostatic gauze "SurgiceI"). Median of hemostasis time consisted of (120 ± 59.9) and (73 ± 46.8) s, in case of application of gauze and powder preparations, respectively. The rate of group using the hemostatic gauze "Surgicel" was (142 ± 77.4) s. The authors made a conclusion on the basis of given research, that the hemostatic material based on oxidize cellulose (the powder form) showed a more expressed hemostatic activity and reliably twice reduced the time of hemostasis as compared with their analog forms of gauze (p < 0.05).


Subject(s)
Bandages , Blood Loss, Surgical/prevention & control , Cellulose, Oxidized/pharmacology , Hemostasis, Surgical , Hemostatics/pharmacology , Animals , Disease Models, Animal , Hemostasis, Surgical/instrumentation , Hemostasis, Surgical/methods , Hemostatic Techniques , Materials Testing/methods , Powders , Rats , Rats, Wistar , Treatment Outcome
13.
Dokl Biochem Biophys ; 465: 361-5, 2015.
Article in English | MEDLINE | ID: mdl-26728725

ABSTRACT

Informative capacity analysis of immunohistochemistry (IHC) and flow cytometry (FCM) in the assessment of estrogen receptor α (ERα) expression in breast cancer tissue was performed. Similar frequencies of expression were shown by both methods: 27% of ERα-negative and 73% ERα-positive cases. However, IHC evaluation detected low levels in only 20% of ERα-positive cases, whereas low levels of ERα detected by FCM were 2 times more often (48%). Moreover, FCM revealed positive expression (23-60%) in 33% of IHC ERα-negative cases. Among IHC ER-positive cases, zero ERα expression was detected by FCM in 12.5%. The approaches to minimize errors in routine clinical determination of the estrogen receptor status were proposed.


Subject(s)
Biomarkers, Tumor/metabolism , Breast Neoplasms/diagnosis , Estrogen Receptor alpha/metabolism , Biomarkers, Tumor/genetics , Estrogen Receptor alpha/genetics , Female , Flow Cytometry , Humans , Immunohistochemistry
14.
J Basic Clin Physiol Pharmacol ; 20(3): 233-63, 2009.
Article in English | MEDLINE | ID: mdl-19852310

ABSTRACT

The goal of the present study was to apply the oscillatory brain dynamics model to the structural and quantitative analysis of neurocognitive functions considered as a potential marker of schizophrenia. This was achieved in tests of the detection of auditory events deviating in the regular auditory stream (oddball paradigm, MMN effect). It was hypothesized that the post-stimulus peaks of the oscillation power localized in post-stimulus time in the definite EEG oscillators represented neuro-electrical 'events' evoked in the specific neuronal nets characterized by this oscillation frequency band. We suggest that the time-frequency destination of these events related to the activation of the functional neuronal nets could be used for the determination of specific neurocognitive functions. Thus it was an attempt to distinguish the different neuro-functional parts of auditory processing and to compare these results between healthy subjects and patients with schizophrenia. The present results demonstrate the significant difference between the frontal averaged EEG oscillatory dynamics in healthy subjects and patients with schizophrenia related to neurocognitive function marked by the MMN and orienting response N200/P300a.


Subject(s)
Cognition Disorders/physiopathology , Electroencephalography , Evoked Potentials, Auditory , Schizophrenia/physiopathology , Acoustic Stimulation/methods , Adult , Analysis of Variance , Case-Control Studies , Cognition Disorders/etiology , Frontal Lobe/physiopathology , Humans , Male , Nerve Net/metabolism , Young Adult
16.
Bull Math Biol ; 68(5): 1053-72, 2006 Jul.
Article in English | MEDLINE | ID: mdl-16832739

ABSTRACT

Fragments of fish melanophore cells can form and center aggregates of pigment granules by dynein-motor-driven transport along a self-organized radial array of microtubules (MTs). We present a quantitative model that describes pigment aggregation and MT-aster self-organization and the subsequent centering of both structures. The model is based on the observations that MTs are immobile and treadmill, while dynein-motor-covered granules have the ability to nucleate MTs. From assumptions based on experimental observations, we derive partial integro-differential equations describing the coupled granule-MT interaction. We use scaling arguments and perturbation theory to study the model in two limiting cases. The model analysis explains the mechanism of aster self-organization as a positive feedback loop between motor aggregation at the MT minus ends and MT nucleation by motors. Furthermore, the centering mechanism is explained by the spontaneous nucleation of MTs throughout the cytosol which acts as a volume sensing tool. Numerical simulations lend additional support to the analysis. The model sheds light on role of polymer dynamics and polymer-motor interactions in cytoskeletal organization.


Subject(s)
Microtubules/physiology , Models, Biological , Animals , Feedback , Fishes , Mathematics , Melanophores/physiology , Melanophores/ultrastructure , Microtubules/ultrastructure , Molecular Motor Proteins/physiology , Pigments, Biological/metabolism
17.
J Basic Clin Physiol Pharmacol ; 15(1-2): 71-105, 2004.
Article in English | MEDLINE | ID: mdl-15485131

ABSTRACT

OBJECTIVES: To study the time locking of the 'natural' (delta, theta, slow alpha, fast alpha and beta) EEG waves during the generation of the P300 in passive (P300a) and active (P300b) auditory oddball paradigms in order to obtain insights into the generation of the P300 and into the transitions between background and evoked activity. METHODS: Tone burst stimuli (standard and deviant) were delivered to normal young adult subjects in passive and active oddball paradigms. The time distributions of EEG waves were analyzed in several frequency bands during background and post-stimulus periods. RESULTS: The ongoing background activity was modified by the deviant stimulus, producing the time locking of the positive delta, theta and alpha EEG deflections in the time range of the P300. This involved prolongation of the positive component of negative-positive wave complexes so that the positive wave was delayed into the time period of the P300. The time locking effects were more prominent in the delta and theta ranges, and differed in frequency components and scalp topography between the two paradigms. Not all deviant stimulus trials contributed deflections to the P300. The contributing trials can be selected, providing the basis for single trial analysis. CONCLUSIONS: The study of the time locking of the EEG waves in different frequency bands provides improved analysis of the P300 and an approach to single deviant stimulus trial analysis, that in turn can enhance signal-to-noise ratios. The results show that the time reorganization of EEG can be considered in the generation of P300 separately from the amplitude factor. SIGNIFICANCE: This can lead to improved analysis of normal and abnormal brain function in individual subjects.


Subject(s)
Acoustic Stimulation/methods , Electroencephalography/classification , Event-Related Potentials, P300/physiology , Adult , Conditioning, Psychological/physiology , Data Collection , Electrodes , Electroencephalography/methods , Electrooculography/methods , Evoked Potentials, Auditory/physiology , Forecasting , Humans , Israel , Male , Time Factors
18.
J Cell Sci ; 117(Pt 8): 1381-97, 2004 Mar 15.
Article in English | MEDLINE | ID: mdl-14996905

ABSTRACT

Polar arrays of microtubules play many important roles in the cell. Normally, such arrays are organized by a centrosome anchoring the minus ends of the microtubules, while the plus ends extend to the cell periphery. However, ensembles of molecular motors and microtubules also demonstrate the ability to self-organize into polar arrays. We use quantitative modeling to analyze the self-organization of microtubule asters and the aggregation of motor-driven pigment granules in fragments of fish melanophore cells. The model is based on the observation that microtubules are immobile and treadmilling, and on the experimental evidence that cytoplasmic dynein motors associated with granules have the ability to nucleate MTs and attenuate their minus-end dynamics. The model explains the observed sequence of events as follows. Initially, pigment granules driven by cytoplasmic dynein motors aggregate to local clusters of microtubule minus ends. The pigment aggregates then nucleate microtubules with plus ends growing toward the fragment boundary, while the minus ends stay transiently in the aggregates. Microtubules emerging from one aggregate compete with any aggregates they encounter leading to the gradual formation of a single aggregate. Simultaneously, a positive feedback mechanism drives the formation of a single MT aster--a single loose aggregate leads to focused MT nucleation and hence a tighter aggregate which stabilizes MT minus ends more effectively leading to aster formation. We translate the model assumptions based on experimental measurements into mathematical equations. The model analysis and computer simulations successfully reproduce the observed pathways of pigment aggregation and microtubule aster self-organization. We test the model predictions by observing the self-organization in fragments of various sizes and in bi-lobed fragments. The model provides stringent constraints on rates and concentrations describing microtubule and motor dynamics, and sheds light on the role of polymer dynamics and polymer-motor interactions in cytoskeletal organization.


Subject(s)
Computational Biology , Dyneins/metabolism , Microtubules/metabolism , Models, Biological , Animals , Cells, Cultured , Computer Simulation , Feedback , Fishes , Melanophores/cytology , Melanophores/metabolism , Pigments, Biological/metabolism , Predictive Value of Tests , Reproducibility of Results
19.
Clin Neurophysiol ; 113(9): 1412-22, 2002 Sep.
Article in English | MEDLINE | ID: mdl-12169322

ABSTRACT

OBJECTIVES: The EEG during background activity and that evoked in response to sensory stimuli (evoked potential, EP) has traditionally been studied by averaging and by frequency analysis. These obscure trial to trial variability. A new analysis technique is presented here which leads to single trial analysis and to insight into the mechanisms of EP generation. METHODS: This technique is based on the identification of the EEG deflections recorded on the scalp before (background) and immediately after visual stimuli. A statistical description of the time and amplitude distributions of these deflections is defined and leads to the differentiation between background and evoked activity. RESULTS: In response to stimuli, the time and amplitude of ongoing deflections (background) are re-organized (time locking) and amplified, generating the EP. Not all stimulus trials are accompanied by an appropriate response. Separate analysis of those single trials that do contain a response deflection provides information on the exact timing, variability, amplitude, etc., of those EEG deflections which contribute to the EP. CONCLUSIONS: New EEG analysis techniques are described which provide single trial EP analysis and insight into mechanisms of EP generation.


Subject(s)
Electroencephalography/methods , Evoked Potentials, Auditory/physiology , Evoked Potentials, Visual/physiology , Signal Processing, Computer-Assisted , Acoustic Stimulation , Adolescent , Adult , Humans , Male , Photic Stimulation , Reference Values , Reproducibility of Results , Sensitivity and Specificity , Time Factors
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