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1.
Front Immunol ; 15: 1401867, 2024.
Article de Anglais | MEDLINE | ID: mdl-38846947

RÉSUMÉ

Tuberculosis (TB), caused by the bacterial pathogen Mycobacterium tuberculosis (MTB), remains one of the most prevalent and deadly infectious diseases worldwide. Currently, there are complex interactions between host cells and pathogens in TB. The onset, progression, and regression of TB are correlated not only with the virulence of MTB but also with the immunity of TB patients. Exosomes are cell-secreted membrane-bound nanovesicles with lipid bilayers that contain a variety of biomolecules, such as metabolites, lipids, proteins, and nucleic acids. Exosome-mediated cell-cell communication and interactions with the microenvironment represent crucial mechanisms through which exosomes exert their functional effects. Exosomes harbor a wide range of regulatory roles in physiological and pathological conditions, including MTB infection. Exosomes can regulate the immune response, metabolism, and cellular death to remodel the progression of MTB infection. During MTB infection, exosomes display distinctive profiles and quantities that may act as diagnostic biomarkers, suggesting that exosomes provide a revealing glimpse into the evolving landscape of MTB infections. Furthermore, exosomes derived from MTB and mesenchymal stem cells can be harnessed as vaccine platforms and drug delivery vehicles for the precise targeting and treatment of TB. In this review, we highlight the functions and mechanisms through which exosomes influence the progression of TB. Additionally, we unravel the critical significance of exosomal constituents in the diagnosis and therapeutic applications of TB, aiming to offer novel perspectives and strategies for combating TB.


Sujet(s)
Marqueurs biologiques , Exosomes , Mycobacterium tuberculosis , Tuberculose , Exosomes/immunologie , Exosomes/métabolisme , Humains , Tuberculose/immunologie , Tuberculose/diagnostic , Tuberculose/thérapie , Tuberculose/microbiologie , Mycobacterium tuberculosis/immunologie , Animaux , Antituberculeux/usage thérapeutique
2.
JMIR Public Health Surveill ; 10: e53948, 2024 Apr 02.
Article de Anglais | MEDLINE | ID: mdl-38564244

RÉSUMÉ

BACKGROUND: Diabetes mellitus (DM) increases the risk of developing tuberculosis (TB), and optimal glycemic control has been shown to reduce the risk of complications and improve the TB treatment outcomes in patients with DM. OBJECTIVE: This study aims to investigate the role of glycemic control in improving TB treatment outcomes among patients with DM. METHODS: MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials databases were searched for randomized controlled trials (RCTs) assessing the impact of oral glycemic control in patients with TB who have DM. Outcomes of interest were radiological findings, treatment success, sputum positivity, and mortality. Evaluations were reported as risk ratios (RRs) with 95% CIs using weighted random-effects models. RESULTS: The analysis included 6919 patients from 7 observational studies. Our meta-analysis showed significant differences between patients with optimal glycemic control and those with poor glycemic control with regard to improved treatment outcomes (RR 1.13, 95% CI 1.02-1.25; P=.02; I²=65%), reduced sputum positivity (RR 0.23, 95% CI 0.09-0.61; P=.003; I²=66%), and fewer cavitary lesions (RR 0.59, 95% CI 0.51-0.68; P<.001; I²=0%) in radiological findings. There was no significant difference between the 2 groups in terms of mortality (RR 0.57, 95% CI 0.22-1.49; P=.25; I²=0%), multilobar involvement (RR 0.57, 95% CI 0.22-1.49; P=.25; I²=0%) on radiologic examination, and upper lobe (RR 0.94, 95% CI 0.76-1.17; P=.58; I²=0%) and lower lobe (RR 1.05, 95% CI 0.48-2.30; P=.91; I²=75%) involvement on radiologic examination. CONCLUSIONS: We concluded that optimal glycemic control is crucial for reducing susceptibility, minimizing complications, and improving treatment outcomes in patients with TB with DM. Emphasizing effective health management and health care strategies are essential in achieving this control. Integrating comprehensive care among patients with TB with DM will enhance patient outcomes and alleviate the burden of disease in this population. TRIAL REGISTRATION: PROSPERO CRD42023427362; https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=427362.


Sujet(s)
Diabète , Tuberculose , Humains , Régulation de la glycémie , Diabète/épidémiologie , Bases de données factuelles , Résultat thérapeutique , Tuberculose/complications , Tuberculose/traitement médicamenteux , Tuberculose/épidémiologie
3.
Front Immunol ; 14: 1305325, 2023.
Article de Anglais | MEDLINE | ID: mdl-38259491

RÉSUMÉ

Tuberculosis (TB) is caused by the bacterial pathogen Mycobacterium tuberculosis (MTB) and is one of the principal reasons for mortality and morbidity worldwide. Currently, recommended anti-tuberculosis drugs include isoniazid, rifampicin, ethambutol, and pyrazinamide. TB treatment is lengthy and inflicted with severe side-effects, including reduced patient compliance with treatment and promotion of drug-resistant strains. TB is also prone to other concomitant diseases such as diabetes and HIV. These drug-resistant and complex co-morbid characteristics increase the complexity of treating MTB. Host-directed therapy (HDT), which effectively eliminates MTB and minimizes inflammatory tissue damage, primarily by targeting the immune system, is currently an attractive complementary approach. The drugs used for HDT are repositioned drugs in actual clinical practice with relative safety and efficacy assurance. HDT is a potentially effective therapeutic intervention for the treatment of MTB and diabetic MTB, and can compensate for the shortcomings of current TB therapies, including the reduction of drug resistance and modulation of immune response. Here, we summarize the state-of-the-art roles and mechanisms of HDT in immune modulation and treatment of MTB, with a special focus on the role of HDT in diabetic MTB, to emphasize the potential of HDT in controlling MTB infection.


Sujet(s)
Diabète , Tuberculose , Humains , Tuberculose/traitement médicamenteux , Diabète/traitement médicamenteux , Antituberculeux/usage thérapeutique , Éthambutol , Isoniazide
4.
Analyst ; 147(22): 5054-5061, 2022 Nov 07.
Article de Anglais | MEDLINE | ID: mdl-36197707

RÉSUMÉ

Exosomes are considered as potential biomarkers that can reflect information from their parent cell-associated cancer microenvironment. Recently, aptasensors have been widely used for cancer and tumor exosome detection. Aptamers related to exosome surface proteins are usually used to introduce a sequence; the aptamer is used for exosome recognition, and the introduced sequence is used to form G-quadruplexes and for signal amplification. In this paper, we found that the EpCAM aptamer is rich in guanine and unimolecular G-quadruplex with a two-layer G-tetrad under acidic conditions, and we investigated its topology, thermal stability and dissociation constant with hemin. Based on this, our proposed colorimetric aptamer sensor combines the unmodified EpCAM aptamer with hemin to construct a hemin/G-quadruplex DNAzyme and catalyze the TMB-H2O2 system to generate a strong colorimetric signal. Therefore, colorimetric signal changes were negatively correlated with the exosome concentration. The linear range of the 1 h assay was 106-108 particles per mL, and the detection limit was 3.94 × 105 particles per mL. In addition, this method can detect exosomes in complex fetal bovine serum samples with good specificity and high sensitivity toward exosomes from breast, liver, and lung cancers with abnormal EpCAM protein expression.


Sujet(s)
Aptamères nucléotidiques , Techniques de biocapteur , ADN catalytique , Exosomes , G-quadruplexes , ADN catalytique/génétique , Hémine/métabolisme , Colorimétrie/méthodes , Exosomes/métabolisme , Peroxyde d'hydrogène/métabolisme , Molécule d'adhérence des cellules épithéliales , Aptamères nucléotidiques/métabolisme , Techniques de biocapteur/méthodes , Limite de détection
5.
J Chromatogr A ; 1663: 462750, 2022 Jan 25.
Article de Anglais | MEDLINE | ID: mdl-34942488

RÉSUMÉ

A simple and efficient dispersive solid-phase extraction (D-SPE) method combined with gas chromatography tandem mass spectrometry (GC-MS/MS) was developed to determine organochlorine pesticides (OCP) in honey. Firstly, a type of hybrid nanocomposite (CD-MOF/TiO2) was prepared by grafting a metal-organic framework material synthesized with cyclodextrin as an organic ligand onto titanium dioxide. Then, the CD-MOF/TiO2 was used as a D-SPE adsorbent to extract the OCP, and the effects of the amount of adsorbent, ultrasonic time, vortex time, pH, and salinity on the extraction were investigated using Plackett-Burman design and Box-Behnken Design. Under the optimized adsorption and desorption conditions, an analysis method that combined D-SPE with GC-MS/MS was established. The linear ranges of 14 OCP are 1-500 µg kg-1 and the correlation coefficients are between 0.9991 and 1.000. The limits of detection and quantification vary from 0.01 to 0.04 µg kg-1 and 0.04 to 0.12 µg kg-1, respectively. The intra-day and inter-day precision of this method are suitable (RSDs% less than 11.3%). The established CD-MOF/TiO2 / D-SPE method was used for the extraction of OCP in honey samples with recovery in the range of 76.4 to 114.3%. The results demonstrate that the CD-MOF/TiO2 has a good selective enrichment ability for OCP and is suitable for the D-SPE pretreat of honey sample analysis.


Sujet(s)
Miel , Réseaux organométalliques , Nanocomposites , Résidus de pesticides , Cyclodextrines bêta , Chromatographie gazeuse-spectrométrie de masse , Miel/analyse , Résidus de pesticides/analyse , Extraction en phase solide , Spectrométrie de masse en tandem , Titane
6.
J Chromatogr A ; 1661: 462680, 2022 Jan 04.
Article de Anglais | MEDLINE | ID: mdl-34879311

RÉSUMÉ

As metabolites of the gut microbiome, short-chain fatty acids (SCFAs) played an important role in the diagnosis of the metabolic diseases. Because of the high polarity, high volatility and complex matrix of biological samples, the highly sensitive, selective and accurate method to determine SCFAs remains a major challenge. Herein, a new method for simultaneous quantification of eleven SCFAs by derivatization combined with solid phase microextraction (SPME) and gas chromatography tandem mass spectrometry (GC-MS/MS) was developed. Isobutyl chloroformate coupled with isobutanol was used as the reaction reagent to derivatize SCFAs. The method validation data showed a satisfactory linearity with the linear regression coefficients (R) ranging from 0.9964 to 0.9996. The limit of detection (LOD) of all SCFAs ranges from 0.01 ng·mL-1 to 0.72 ng·mL-1 and the limit of quantification (LOQ) ranges from 0.04 ng·mL-1 to 2.41 ng·mL-1. The intra-day and inter-day precision (RSDs) ranged from 0.65% to 8.92% and 1.62% to 15.61%, respectively. The recovery ranged from 88.10% to 108.71%. Finally, the developed method was successfully used to determine SCFAs in mice fecal sample, and ten of the SCFAs were found in feces of mice, including formic acid.


Sujet(s)
Microextraction en phase solide , Spectrométrie de masse en tandem , Animaux , Acides gras volatils , Fèces , Chromatographie gazeuse-spectrométrie de masse , Limite de détection , Souris
7.
Acta Trop ; 224: 106073, 2021 Dec.
Article de Anglais | MEDLINE | ID: mdl-34487719

RÉSUMÉ

In western societies, the prevalence of type 2 diabetes (T2D) is related to the hygiene hypothesis, which implies that reduced exposure to infectious factors results in a loss of the immune stimulation necessary to form the immune system during development. In fact, it has been reported that parasites, such as Schistosoma, can improve or prevent the development of T2D, which may be related to the activity of immune cells, including regulatory T cells (Tregs). Hence, Schistosoma, Tregs, and T2D share a close relationship. Schistosoma infection and the molecules released can lead to an increase in Tregs, which play an important role in the suppression of T2D. In this review, we provide an overview of the role of Tregs in the response to Schistosoma infection and the protective mechanism of Schistosoma-related molecular products against T2D.


Sujet(s)
Diabète de type 2 , Lymphocytes T régulateurs , Animaux , Diabète de type 2/prévention et contrôle , Schistosoma
8.
BMC Endocr Disord ; 21(1): 123, 2021 Jun 16.
Article de Anglais | MEDLINE | ID: mdl-34134685

RÉSUMÉ

BACKGROUND: Diabetes is a well-known risk factor for tuberculosis and poorly glycemic control may increase the risk of tuberculosis. We performed a meta-analysis to explore the association of glycemic control in diabetic patients and their tuberculosis prevalence. METHODS: We included observational studies that investigated the prevalence of tuberculosis associated with glycemic control. The markers of glycated hemoglobin A1c (HbA1c) and fasting plasma glucose were used to evaluate the exposure of interest in the study. We searched related articles in PubMed, EMBASE and Web of Science through 14 December 2019. The Newcastle-Ottawa scale was used to assess the risk of bias of included studies. RESULTS: Seventeen studies (four cohort studies, five case-control studies and eight cross-sectional studies) were included, involving 1,027,074 participants. The meta-analysis found the pooled odds ratio of prevalent tuberculosis increased a 2.05-fold (95%CI: 1.65, 2.55) for the patients with HbA1c ≥7.0% compared to those with HbA1c concentration < 7.0%. Furthermore, we found the mean of HbA1c was higher in the diabetes mellitus with tuberculosis group than the diabetes-only group (P = 0.002). In the sensitivity analysis, the finding remains consistent. CONCLUSION: Our study provides the evidence that poorly controlled diabetes in diabetics may be associated with increased prevalence of tuberculosis. More efforts should focus on screening tuberculosis in uncontrolled diabetes.


Sujet(s)
Marqueurs biologiques/sang , Complications du diabète/épidémiologie , Diabète/physiopathologie , Tuberculose/épidémiologie , Glycémie/analyse , Complications du diabète/sang , Complications du diabète/diagnostic , Hémoglobine glyquée/analyse , Humains , Pronostic , Facteurs de risque , Tuberculose/sang , Tuberculose/diagnostic
9.
J Chromatogr A ; 1648: 462192, 2021 Jul 05.
Article de Anglais | MEDLINE | ID: mdl-33984649

RÉSUMÉ

Determination of folic acid and riboflavin in biological samples is difficult due to their high polarity, low concentration, chemical instability, and complex matrix. In this study, the polypyrrole-coated magnetic nanocomposite (Fe3O4@PPy) was synthesized innovatively with the assistance of hexadecyltrimethylammonium bromide. To evaluate the adsorption mechanism and the feasibility of synthesized Fe3O4@PPy as an adsorbent, the adsorption capacities, kinetics and thermodynamics of folic acid and riboflavin were investigated systemically. Furthermore, in light of the chemical instability of folic acid and riboflavin a method for rapid extraction and detection of them from human urine within 10 min was developed successfully by combining magnetic solid phase extraction with ultra-performance liquid chromatography (MSPE/UPLC). The adsorption parameters including sorbent amount, pH value, extraction time, desorption solvent and desorption time were studied. Under optimum conditions, the performance of the established determination method was validated with the linearly dependent coefficients (>0.9995), the limits of detection (0.02-0.05 µg/mL), the limits of quantification (0.07-0.18 µg/mL), and the recoveries (92.2-105.1%, with relative standard deviation < 3.3%). The rapid extraction and detection of folic acid and riboflavin from real urine samples were achieved subsequently. The present study suggests that the developed method exhibits a promising application in the analysis of free folic acid and riboflavin in human urine samples, which can provide a reference for the clinical drug monitoring and treatment.


Sujet(s)
Chromatographie en phase liquide/méthodes , Acide folique/urine , Magnétisme/méthodes , Polymères/composition chimique , Pyrroles/composition chimique , Riboflavine/urine , Extraction en phase solide/méthodes , Adsorption , Humains , Limite de détection , Nanocomposites/composition chimique , Solvants/composition chimique
10.
Int J Biol Macromol ; 94(Pt A): 451-458, 2017 Jan.
Article de Anglais | MEDLINE | ID: mdl-27765573

RÉSUMÉ

A water-soluble polysaccharide (STPC2) was isolated from the boiling-water extract of Sargassum thunbergii, purified by CaCl2 precipitation and chromatography on DEAE-cellulose and Sephacryl S-300 column. It was found that STPC2, with a molecular weight of 57kD, was composed of fucose, xylose, galactose and glucuronic acid, in a ratio of 8.1: 3.8: 2.1: 1.0. Additionally, we found that STPC2 significantly inhibited endothelial cell migration and tube formation without toxicity. Moreover, STPC2 significantly inhibited lung cancer cell A549 migration and proliferation. It was found that STPC2 treatment suppressed MMP-2 gene expression at transcriptional level and enzymatic activity. Furthermore, STPC2 reduced the mRNA and protein expression of vascular endothelial growth factor-A (VEGF-A) and hypoxia-inducible factor (HIF)-1 alpha in the endothelial cells. Taken together, our findings indicated that STPC2 was a potent bioactive polysaccharide with distinct anti-angiogenesis activity against tumor migration via down-regulation of MMP-2 activity and VEGF/HIF-1α signaling pathway.


Sujet(s)
Inhibiteurs de l'angiogenèse/pharmacologie , Sous-unité alpha du facteur-1 induit par l'hypoxie/métabolisme , Matrix metalloproteinase 2/métabolisme , Polyosides/pharmacologie , Cellules A549 , Inhibiteurs de l'angiogenèse/composition chimique , Inhibiteurs de l'angiogenèse/isolement et purification , Mouvement cellulaire/effets des médicaments et des substances chimiques , Survie cellulaire/effets des médicaments et des substances chimiques , Chromatographie sur gel , Chromatographie en phase liquide à haute performance , Régulation négative , Tests de criblage d'agents antitumoraux , Cellules endothéliales de la veine ombilicale humaine/effets des médicaments et des substances chimiques , Cellules endothéliales de la veine ombilicale humaine/métabolisme , Humains , Polyosides/composition chimique , Polyosides/isolement et purification , Sargassum/composition chimique , Transduction du signal , Facteur de croissance endothéliale vasculaire de type A/physiologie
11.
Microsc Res Tech ; 75(3): 388-96, 2012 Mar.
Article de Anglais | MEDLINE | ID: mdl-21898668

RÉSUMÉ

Morphological observation and analysis of cerebral microvascular network is an essential way to study cerebral function. Automated labeling of cerebral microvascular in microscopy images is one of the key steps for quantitative analysis of microvascular network in the specimens of brain mantle. It is presented in this work that an automated image processing approach based on curvilinear structure detector is applied to label and analyze the microvascular in the image. Steerable filter is also introduced to address the detecting confusion in branching regions. And then the vascular morphology analysis, such as average microvascular density, is also performed after image processing. Validation has demonstrated that the results from proposed approach are satisfied. The proposed method is finally applied in the study of cerebral microvascular dysfunction induced by γ-ray irradiation.


Sujet(s)
Cortex cérébral/vascularisation , Traitement d'image par ordinateur/méthodes , Algorithmes , Animaux , Cortex cérébral/effets des radiations , Circulation cérébrovasculaire/effets des radiations , Rayons gamma/effets indésirables , Souris , Souris de lignée ICR , Microvaisseaux/anatomopathologie , Microvaisseaux/effets des radiations , Logiciel
12.
Comput Methods Biomech Biomed Engin ; 14(4): 371-8, 2011 Apr.
Article de Anglais | MEDLINE | ID: mdl-21442495

RÉSUMÉ

Alzheimer's disease (AD) is considered one of the most common age-associated neurodegenerative disorders, affecting millions of senior people worldwide. Combination of protein-protein interaction (PPI) network analysis and gene expression studies provides a better insight into AD. A computational approach was developed in our work to identify protein signal pathways between amyloid precursor proteins and tau proteins, which are well known as important proteins for AD. First, a modified LA-SEN method, called the network-constrained regularisation analysis, was applied to microarray data from a transgenic mouse model and AD patients. Then protein pathways were constructed based on an integer linear programming model to integrate microarray data and the PPI database. Important pathways of AD, including some cancer-related pathways, were identified finally.


Sujet(s)
Maladie d'Alzheimer/métabolisme , Analyse de profil d'expression de gènes , Protéines/métabolisme , Transduction du signal , Algorithmes , Maladie d'Alzheimer/génétique , Précurseur de la protéine bêta-amyloïde/génétique , Précurseur de la protéine bêta-amyloïde/métabolisme , Animaux , Glycogen Synthase Kinase 3/génétique , Glycogen Synthase Kinase 3/métabolisme , Modèles linéaires , Souris , Souris de lignée C57BL , Souris transgéniques , Protéines/génétique , Protéines tau/génétique , Protéines tau/métabolisme
13.
Radiat Res ; 175(1): 1-9, 2011 Jan.
Article de Anglais | MEDLINE | ID: mdl-21175341

RÉSUMÉ

Our purpose was to noninvasively assess formation of the microvasculature, blood-brain barrier (BBB) and blood-CSF barrier formation of prenatal X-ray-induced CNS abnormalities using quantitative MRI. Eight pregnant female Sprague-Dawley rats were divided into two groups consisting of control and X-irradiated animals. After birth, 20 neonatal male rats were divided into four groups of five rats. To evaluate the development of the BBB, changes in T(1) induced by Gd-DTPA were compared quantitatively in normal and prenatally irradiated animals in the formative period 1 to 2 weeks after birth. To assess the abnormalities of the microvasculature, quantitative perfusion MRI and MR angiography were also used. Histology was also performed to evaluate the BBB (albumin) and vascular endothelial cells (laminin). Decreased cerebral blood flow (CBF) and angioarchitectonic abnormalities were observed in the prenatally irradiated rats. However, abnormalities of the BBB and blood-CSF barrier were not observed using Gd-enhanced MRI and albumin staining. Quantitative perfusion MRI, MR angiography and Gd-enhanced T(1) mapping are useful for assessing CNS disturbance after prenatal exposure to radiation. These techniques provide important diagnostic information for assessing the condition of patients during the early stages of life after accidental or unavoidable prenatal exposure to radiation.


Sujet(s)
Malformations radio-induites/diagnostic , Encéphale/malformations , Imagerie par résonance magnétique/méthodes , Rayons X/effets indésirables , Albumines/analyse , Animaux , Barrière hémato-encéphalique , Circulation cérébrovasculaire/effets des radiations , Femelle , Acide gadopentétique , Immunohistochimie , Laminine/analyse , Angiographie par résonance magnétique , Mâle , Grossesse , Rats , Rat Sprague-Dawley
14.
Microsc Res Tech ; 73(2): 109-18, 2010 Feb.
Article de Anglais | MEDLINE | ID: mdl-19697431

RÉSUMÉ

Neurons that come to populate the six-layered cerebral cortex are born deep within the developing brain in the surface of the embryonic cerebral ventricles. It is very important to detect these neurons for studying histogenesis of the brain and abnormal migration that had been linked to cognitive deficits, mental retardation, and motor disorders. The visualization of labeled cells in brain sections was performed by immunocytochemical examination and its image data were documented to microscopic pictures. Based on the fact, automatic accurate neurons labeling is prerequisite instead of time-consuming manual labeling. In this article, a fully automated image processing approach is proposed to detect all the stained neurons in microscopic images. First of all, dark stained neurons are achieved by thresholding in blue channel of image. And then a modified fuzzy c-means clustering method, called alternative fuzzy c-means is applied to achieve higher classification accuracy in extracting constraint factor. Finally, watershed based on gradient vector flow is employed to the constraint factor image to segment all the neurons, including clustered neurons. The results demonstrate that the proposed method can be a useful tool in neuron image analysis.


Sujet(s)
Automatisation/méthodes , Encéphale/cytologie , Mouvement cellulaire , Traitement d'image par ordinateur/méthodes , Microscopie/méthodes , Neurones/physiologie , Animaux , Femelle , Mâle , Souris , Souris de lignée ICR , Grossesse , Coloration et marquage/méthodes
15.
Brain Struct Funct ; 213(4-5): 469-80, 2009 Sep.
Article de Anglais | MEDLINE | ID: mdl-19214566

RÉSUMÉ

The aim of this study was to spatio-temporally clarify gross structural changes in the forebrain of cynomolgus monkey fetuses using 7-tesla magnetic resonance imaging (MRI). T(1)-weighted coronal, horizontal, and sagittal MR slices of fixed left cerebral hemispheres were obtained from one male fetus at embryonic days (EDs) 70-150. The timetable for fetal sulcation by MRI was in good agreement with that by gross observations, with a lag time of 10-30 days. A difference in detectability of some sulci seemed to be associated with the length, depth, width, and location of the sulci. Furthermore, MRI clarified the embryonic days of the emergence of the callosal (ED 70) and circular (ED 90) sulci, which remained unpredictable under gross observations. Also made visible by the present MRI were subcortical structures of the forebrain such as the caudate nucleus, globus pallidus, putamen, major subdivisions of the thalamus, and hippocampal formation. Their adult-like features were formed by ED 100, corresponding to the onset of a signal enhancement in the gray matter, which reflects neuronal maturation. The results reveal a highly reproducible level of gross structural changes in the forebrain using a high spatial 7-tesla MRI. The present MRI study clarified some changes that are difficult to demonstrate nondestructively using only gross observations, for example, the development of cerebral sulci located on the deep portions of the cortex, as well as cortical and subcortical neuronal maturation.


Sujet(s)
Macaca fascicularis/embryologie , Prosencéphale/embryologie , Prosencéphale/physiologie , Animaux , Cartographie cérébrale , Femelle , Développement foetal , Traitement d'image par ordinateur , Imagerie par résonance magnétique , Mâle , Grossesse
17.
J Med Invest ; 54(3-4): 322-30, 2007 Aug.
Article de Anglais | MEDLINE | ID: mdl-17878682

RÉSUMÉ

The present study was designed to present evidence to clarify the relationships between learning ability, neuronal cell adhesion molecule L1 expression and hippocampal structural changes in the rat model received X-irradiation at an embryonic stage (E15). Water maze task indicated that all of the irradiated rats failed to learn the task in the whole training procedure. Their latency to the platform and swimming distance were significant differences from those sham-treated controls. Histological studies showed that the hippocampal ectopias induced by X-rays in the CA1 were involved in the spatial learning impairment, in which they hampered normal processes in learning development and transmission of information. Number, size and positions of the ectopias in the dorsal parts of the hippocampus were confirmed to be related to degrees of spatial learning impairment. On the other hand, L1 expression in the hippocampus was examined with Western blot analysis. The results indicated a lower content of L1 in the irradiated rats. A decrease in L1 might be one of reasons to cause disorganization of the septohippocampal pathways. These findings suggest some mechanisms of spatial learning impairment can be attributed to the formation of the hippocampal ectopias and redaction of L1 following prenatal exposure to X-irradiation.


Sujet(s)
Apprentissage du labyrinthe/physiologie , Apprentissage du labyrinthe/effets des radiations , Molécule d'adhérence cellulaire neurale L-1/métabolisme , Animaux , Femelle , Hippocampe/embryologie , Hippocampe/anatomopathologie , Hippocampe/physiologie , Hippocampe/effets des radiations , Mâle , Grossesse , Effets différés de l'exposition prénatale à des facteurs de risque , Rats , Rat Wistar
18.
Congenit Anom (Kyoto) ; 44(1): 46-50, 2004 Mar.
Article de Anglais | MEDLINE | ID: mdl-15008900

RÉSUMÉ

This study examined immunohistochemically the expression of an enzymatically active form of tyrosine hydroxylase (TH), phosphorylated TH at Ser40 (phospho-TH), in the cerebellum of ataxic mutant mice, rolling mouse Nagoya (RMN) and dilute-lethal (DL). TH immunostaining appeared in some Purkinje cells in RMN and DL, but in a few of the Purkinje cells of littermate controls for both mutants. In all groups of mice, there were no phospho-TH immunoreactive Purkinje cells in the cerebellum, although the subsets of TH immunoreactive Purkinje cells were found in the adjacent sections. The results suggest that TH expression in the Purkinje cells of ataxic mutants abnormally increases without activation of this enzyme by phosphorylation. This may mean that TH in Purkinje cells is not related to catecholamine synthesis.


Sujet(s)
Ataxie/génétique , Cellules de Purkinje/métabolisme , Sérine/métabolisme , Tyrosine 3-monooxygenase/génétique , Animaux , Ataxie/métabolisme , Cervelet/anatomopathologie , Femelle , Immunohistochimie , Mâle , Souris , Phosphorylation , Tyrosine 3-monooxygenase/métabolisme
19.
J Med Invest ; 51(1-2): 103-7, 2004 Feb.
Article de Anglais | MEDLINE | ID: mdl-15000263

RÉSUMÉ

Heavy-ion beams have the feature to administer a large radiation dose in the vicinity of the endpoint in the beam range, its irradiation system and biophysical characteristics are different from ordinary irradiation instruments like X-rays or gamma-rays. In order to get clarify characteristic effects of heavy-ion beams on the brain, we have developed an experimental system for irradiating a restricted region of the rat brain using heavy-ion beams. The left cerebral hemispheres of the adult rat brain were irradiated at dose of 50 Gy charged carbon particles (290 MeV/nucleon; 5 mm spread-out Bragg peak). After irradiation, the characteristics of the heavy-ion beams and the animal model were studied. Histological examination and measurement showed that extensive necrosis was observed between 2.5 mm and 7.5 mm depth from the surface of the rat head, suggesting a relatively high dose and uniform dose was delivered among designed depths and the spread-out Bragg peak used here successfully and satisfactorily retained its high-dose localization in the defined region. We believe that our experimental model for irradiating a restricted region of the rat brain using heavy-ion beams is a good model for analyzing regional radiation susceptibility of the brain.


Sujet(s)
Encéphale/effets des radiations , Animaux , Encéphale/anatomopathologie , Ions lourds , Mâle , Modèles animaux , Dose de rayonnement , Radiotolérance , Rats , Rat Sprague-Dawley
20.
J Radiat Res ; 45(4): 563-9, 2004 Dec.
Article de Anglais | MEDLINE | ID: mdl-15635267

RÉSUMÉ

The relationship between an impairment of spatial navigation and an incidence of ectopic neurons in the dorsal hippocampus was investigated in adult rats that were prenatally exposed to X-ray irradiation. Adult rats which had received 1.5 Gy X-rays at embryonic day 15 (E15) showed significant learning disability in the water-maze task. According to the mean value of the swimming time, we categorized the irradiated adult rats into the following three groups: slightly damaged group, mildly damaged group and severely damaged group. No significant difference in the brain weight was found between the three categorized groups. Ectopic neurons appearing at abnormal places were prominently observed in the dorsal hippocampus of the severely damaged group with a remarkable learning disturbance, while no ectopia in the hippocampus was observed in the slightly damaged group. This may suggest that the cognitive dysfunction induced by prenatal exposure to X-ray irradiation may be, at least in part, attributable to ectopic neurons of the hippocampus.


Sujet(s)
Hippocampe/métabolisme , Hippocampe/effets des radiations , Exposition maternelle , Neurones/métabolisme , Animaux , Encéphale/anatomopathologie , Femelle , Hippocampe/anatomopathologie , Incapacités d'apprentissage/étiologie , Mâle , Apprentissage du labyrinthe , Grossesse , Gestation animale , Effets différés de l'exposition prénatale à des facteurs de risque , Rats , Rat Wistar , Perception de l'espace , Facteurs temps , Distribution tissulaire , Rayons X
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