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1.
Int Immunopharmacol ; 135: 112311, 2024 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-38781607

RESUMO

OBJECTIVE: Obstructive Sleep Apnea (OSA) during pregnancy is characterized by intermittent hypoxia (IH) during sleep and will lead to the rise of oxidative stress in the fetal body. Pyroptosis, a type of inflammatory and programmable cell death mediated by Gasdermin D (GSDMD), plays a substantial role in oxygen deprivation's contribution to neural system damage. Existing research shows that Nicotinamide Adenine Dinucleotide Phosphate (NADPH) plays a protective role in alleviating brain tissue pyroptosis. We speculate that exogenous NADPH may play a protective role in OSA during pregnancy. METHODS: A model of GIH group was established to simulate the pathophysiological mechanisms of OSA during pregnant and AIR group was established by giving the same frequency. Sham group was established by injecting NS and the NADPH group was established and given exogenous NADPH. We utilized the Morris Water Maze to assess cognitive function impairment, Luxol Fast Blue (LBF) staining to confirm myelin sheath formation, TUNEL staining to examine cell death in fetal mice brain tissue, and Western blotting to detect pertinent protein expressions. RESULTS: The GIH group offspring exhibited decreases in spatial learning and memory abilities, reduced numbers of oligodendrocytes and formed myelin, as well as increased expression of pyroptosis-related proteins. The NADPH group offspring showed restoration in spatial learning and memory abilities increased counts of oligodendrocytes and formed myelin sheaths, in addition to decreased expression of pyroptosis-related. CONCLUSIONS: This study demonstrates that early injection of exogenous NADPH can alleviate the damage to fetal brain development caused by gestational intermittent hypoxia (GIH).


Assuntos
NADP , Piroptose , Animais , Gravidez , Feminino , Camundongos , NADP/metabolismo , Lesões Encefálicas/patologia , Lesões Encefálicas/metabolismo , Hipóxia/metabolismo , Encéfalo/patologia , Encéfalo/metabolismo , Modelos Animais de Doenças , Masculino , Camundongos Endogâmicos C57BL , Efeitos Tardios da Exposição Pré-Natal
2.
Front Neurosci ; 17: 1227081, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37547140

RESUMO

Background: There is increasing evidence that patients with retinal detachment (RD) have aberrant brain activity. However, neuroimaging investigations remain focused on static changes in brain activity among RD patients. There is limited knowledge regarding the characteristics of dynamic brain activity in RD patients. Aim: This study evaluated changes in dynamic brain activity among RD patients, using a dynamic amplitude of low-frequency fluctuation (dALFF), k-means clustering method and support vector machine (SVM) classification approach. Methods: We investigated inter-group disparities of dALFF indices under three different time window sizes using resting-state functional magnetic resonance imaging (rs-fMRI) data from 23 RD patients and 24 demographically matched healthy controls (HCs). The k-means clustering method was performed to analyze specific dALFF states and related temporal properties. Additionally, we selected altered dALFF values under three distinct conditions as classification features for distinguishing RD patients from HCs using an SVM classifier. Results: RD patients exhibited dynamic changes in local intrinsic indicators of brain activity. Compared with HCs, RD patients displayed increased dALFF in the bilateral middle frontal gyrus, left putamen (Putamen_L), left superior occipital gyrus (Occipital_Sup_L), left middle occipital gyrus (Occipital_Mid_L), right calcarine (Calcarine_R), right middle temporal gyrus (Temporal_Mid_R), and right inferior frontal gyrus (Frontal_Inf_Tri_R). Additionally, RD patients showed significantly decreased dALFF values in the right superior parietal gyrus (Parietal_Sup_R) and right paracentral lobule (Paracentral_Lobule_R) [two-tailed, voxel-level p < 0.05, Gaussian random field (GRF) correction, cluster-level p < 0.05]. For dALFF, we derived 3 or 4 states of ALFF that occurred repeatedly. There were differences in state distribution and state properties between RD and HC groups. The number of transitions between the dALFF states was higher in the RD group than in the HC group. Based on dALFF values in various brain regions, the overall accuracies of SVM classification were 97.87, 100, and 93.62% under three different time windows; area under the curve values were 0.99, 1.00, and 0.95, respectively. No correlation was found between hamilton anxiety (HAMA) scores and regional dALFF. Conclusion: Our findings offer important insights concerning the neuropathology that underlies RD and provide robust evidence that dALFF, a local indicator of brain activity, may be useful for clinical diagnosis.

3.
Front Neurosci ; 17: 1126262, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36816124

RESUMO

Aim: This study was conducted to explore differences in static functional connectivity (sFC) and dynamic functional connectivity (dFC) alteration patterns in the primary visual area (V1) among high myopia (HM) patients and healthy controls (HCs) via seed-based functional connectivity (FC) analysis. Methods: Resting-state functional magnetic resonance imaging (fMRI) scans were performed on 82 HM patients and 59 HCs who were closely matched for age, sex, and weight. Seed-based FC analysis was performed to identify alterations in the sFC and dFC patterns of the V1 in HM patients and HCs. Associations between mean sFC and dFC signal values and clinical symptoms in distinct brain areas among HM patients were identified via correlation analysis. Static and dynamic changes in brain activity in HM patients were investigated by assessments of sFC and dFC via calculation of the total time series mean and sliding-window analysis. Results: In the left anterior cingulate gyrus (L-ACG)/left superior parietal gyrus (L-SPG) and left V1, sFC values were significantly greater in HM patients than in HCs. In the L-ACG and right V1, sFC values were also significantly greater in HM patients than in HCs [two-tailed, voxel-level P < 0.01, Gaussian random field (GRF) correction, cluster-level P < 0.05]. In the left calcarine cortex (L-CAL) and left V1, dFC values were significantly lower in HM patients than in HCs. In the right lingual gyrus (R-LING) and right V1, dFC values were also significantly lower in HM patients than in HCs (two-tailed, voxel-level P < 0.01, GRF correction, cluster-level P < 0.05). Conclusion: Patients with HM exhibited significantly disturbed FC between the V1 and various brain regions, including L-ACG, L-SPG, L-CAL, and R-LING. This disturbance suggests that patients with HM could exhibit impaired cognitive and emotional processing functions, top-down control of visual attention, and visual information processing functions. HM patients and HCs could be distinguished from each other with high accuracy using sFC and dFC variabilities. These findings may help to identify the neural mechanism of decreased visual performance in HM patients.

4.
Front Hum Neurosci ; 16: 959523, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35992950

RESUMO

Aim: Patients with high myopia (HM) reportedly exhibit changes in functional brain activity, but the mechanism underlying such changes is unclear. This study was conducted to observe differences in dynamic spontaneous brain activity between patients with HM and healthy controls (HCs) via dynamic regional homogeneity (dReHo) analysis. Methods: Resting-state functional magnetic resonance imaging (rs-fMRI) scans were performed on 82 patients with HM and 59 HCs who were closely matched for age, sex, and weight. The dReHo approach was used to assess local dynamic activity in the human brain. The association between mean dReHo signal values and clinical symptoms in distinct brain areas in patients with HM was determined via correlation analysis. Results: In the left fusiform gyrus (L-FG), right inferior temporal gyrus (R-ITG), right Rolandic operculum (R-ROL), right postcentral gyrus (R-PoCG), and right precentral gyrus (R-PreCG), dReHo values were significantly greater in patients with HM than in HCs. Conclusion: Patients with HM have distinct functional changes in various brain regions that mainly include the L-FG, R-ITG, R-ROL, R-PoCG, and R-PreCG. These findings constitute important evidence for the roles of brain networks in the pathophysiological mechanisms of HM and may aid in the diagnosis of HM.

5.
Front Hum Neurosci ; 16: 910846, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35814958

RESUMO

Purpose: To study the changes in functional connections between the left and right hemispheres of patients with high myopia (HM) and healthy controls (HCs) by resting functional magnetic resonance imaging (fMRI) based on voxel-mirrored homotopic connectivity (VMHC). To study the changes in resting-state functional connectivity (rsFC) between the left and right hemispheres of patients with HM and healthy controls (HCS) at rest by using resting functional magnetic resonance imaging (fMRI) based on voxel-mirror homotopy connectivity (VMHC). Patients and Methods: A total of 89 patients with HM (41 men and 48 women) and 59 HCs (24 men and 35 women) were collected and matched according to gender, age, and education level. The VMHC method was used to evaluate the changes in rsFC between cerebral hemispheres, and a correlation analysis was carried out to understand the differences in brain functional activities between the patients with HM and the HCs. Results: Compared with the HCs, the VMHC values of the putamen and fusiform in the HM group were significantly lower (voxel-level p < 0.01, Gaussian random field correction cluster level p < 0.05). Conclusion: This study preliminarily confirmed the destruction of interhemispheric functional connection in some brain regions of the patients with HM and provided effective information for clarifying the neural mechanism of patients with HM.

6.
Front Hum Neurosci ; 16: 870350, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35496062

RESUMO

Aim: Resting state functional magnetic resonance imaging (rs-fMRI) was used to analyze changes in functional connectivity (FC) within various brain networks and functional network connectivity (FNC) among various brain regions in patients with high myopia (HM). Methods: rs-fMRI was used to scan 82 patients with HM (HM group) and 59 healthy control volunteers (HC group) matched for age, sex, and education level. Fourteen resting state networks (RSNs) were extracted, of which 11 were positive. Then, the FCs and FNCs of RSNs in HM patients were examined by independent component analysis (ICA). Results: Compared with the HC group, FC in visual network 1 (VN1), dorsal attention network (DAN), auditory network 2 (AN2), visual network 3 (VN3), and sensorimotor network (SMN) significantly increased in the HM group. FC in default mode network 1 (DMN1) significantly decreased. Furthermore, some brain regions in default mode network 2 (DMN2), default mode network 3 (DMN3), auditory network 1 (AN1), executive control network (ECN), and significance network (SN) increased while others decreased. FNC analysis also showed that the network connection between the default mode network (DMN) and cerebellar network (CER) was enhanced in the HM group. Conclusion: Compared with HCs, HM patients showed neural activity dysfunction within and between specific brain networks, particularly in the DMN and CER. Thus, HM patients may have deficits in visual, cognitive, and motor balance functions.

7.
Int J Gen Med ; 14: 10315-10325, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34992446

RESUMO

PURPOSE: Converging evidence demonstrated that bronchial asthma (BA) individuals with hypoxia were associated with functional and morphological reorganization in the brain. However, the alterations of the interhemispheric functional connectivity in BA individuals remain unknown. The purpose of this study was to assess the interhemispheric functional connectivity changes in individuals with hypoxia due to middle-aged BA using voxel-mirrored homotopic connectivity (VMHC) methods. METHODS: In total, 31 BA individuals and 30 healthy controls (HCs) closely matched in age, sex, and education underwent resting-state magnetic resonance imaging (MRI) scans. VMHC analysis was performed to investigate differences in interhemispheric functional connectivity between the two groups. Then, a seed-based resting-state functional connectivity (rsFC) analysis was conducted to further reveal the abnormal functional connectivity between the altered VMHC regions and the whole brain. RESULTS: Compared with HCs, BA individuals had significantly lower VMHC values in the bilateral basal ganglia/thalamus/insula, cuneus/calcarine/lingual gyrus, precentral and postcentral gyrus. [voxel level P < 0.01, Gaussian random field (GRF) correction, cluster level P < 0.05]. Taking VMHC altered brain areas as seed points, the rsFC values of left insula/supramarginal/postcentral gyrus (PostCG)/inferior parietal lobule (IPL) brain areas in BA were increased. CONCLUSION: The abnormal resting-state functional connectivity of middle-aged BA is altered in specific brain regions related to the basal ganglia network, visual network, and sensorimotor network, which may be related to the neuropathogenesis of asthma patients. Furthermore, these VMHC and FC values may be important clinical indicators for the diagnosis and treatment of asthma patients.

8.
Angew Chem Int Ed Engl ; 59(50): 22652-22658, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-32869491

RESUMO

The development of new principles and techniques with high neuronal compatibility for quantitatively monitoring the dynamics of neurochemicals is essential for deciphering brain chemistry and function but remains a great challenge. We herein report a neuron-compatible method for in vivo neurochemical sensing by powering a single carbon fiber through spontaneous bipolar electrochemistry as a new sensing platform. By using ascorbic acid as a model target to prove the concept, we found that the single-carbon-fiber-powered microsensor exhibited a good response, high stability and, more importantly, excellent neuronal compatibility. The microsensor was also highly compatible with electrophysiological recording, thus enabling the synchronous recording of both chemical and electrical signals. The sensing principle could be developed for in vivo monitoring of various neurochemicals in the future by rationally designing and tuning the electrochemical reactions at the two poles of the carbon fiber.


Assuntos
Ácido Ascórbico/análise , Fibra de Carbono/química , Neurônios/química , Técnicas Biossensoriais , Química Encefálica , Técnicas Eletroquímicas , Humanos
9.
J Med Virol ; 91(9): 1625-1632, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31066075

RESUMO

BACKGROUND: Human parainfluenza virus (HPIV), usually combined with other pathogens, causes lower respiratory tract infection (LRTI) in children. However, clinical characteristics of HPIV coinfection with other pathogens were unclear. This study aimed to investigate the viral and atypical bacterial etiology of LRTI in children and compare the clinical characteristics of HPIV single infection with those of coinfection. METHODS: This study included 1335 patients, aged between 1 to 71 months, diagnosed with LRTI in Yuying Children's Hospital, Zhejiang, China, from December 2013 to June 2015. Nasopharyngeal secretions were collected, and respiratory pathogens were detected using Multiplex polymerase chain reaction. The clinical data of patients were collected and analyzed. RESULTS: At least 1 pathogen was detected in 1181/1335 (88.5%) patients. The pathogens identified most frequently were respiratory syncytial virus, human rhinovirus, HPIV, adenovirus, and human metapneumovirus. The coinfection rate was 24.8%. HPIV coinfection with other viruses was more associated with running nose, shortness of breath, and oxygen support compared with HPIV single infection. Moreover, HPIV coinfection with atypical bacteria was more related to running nose, moist rales, and longer hospital duration compared with HPIV single infection, and also to longer hospital duration compared with coinfection with other viruses. CONCLUSIONS: This study demonstrated that viral infections were highly associated with LRTI and the rate of coinfection was high. HPIV single infection was milder than coinfection with other viruses. Moreover, HPIV coinfection with atypical bacteria was more serious than HPIV single infection and coinfection with other viruses.


Assuntos
Coinfecção/epidemiologia , Coinfecção/virologia , Infecções por Paramyxoviridae/epidemiologia , Infecções por Paramyxoviridae/virologia , Infecções Respiratórias/epidemiologia , Infecções Respiratórias/virologia , Respirovirus , Fatores Etários , Pré-Escolar , China/epidemiologia , Comorbidade , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Reação em Cadeia da Polimerase Multiplex , Infecções por Paramyxoviridae/diagnóstico , Vigilância em Saúde Pública , Infecções Respiratórias/diagnóstico , Respirovirus/classificação , Respirovirus/genética
10.
J Bone Miner Metab ; 36(4): 488-497, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-28884379

RESUMO

Osteoporosis (OP) is an increasing public health problem worldwide. Genetic factors are considered to be major contributors to the pathogenesis of OP. The aim of this study was to investigate the association of the purinergic P2X7 receptor (P2X7R) and estrogen receptor-α (ER-α) genes with OP risk, and the effect of the possible interaction between the two genes on predisposition to OP in Chinese postmenopausal women. A total of 596 subjects, including 350 OP patients and 246 controls, were recruited in this case-control study. Five functional single-nucleotide polymorphisms (SNPs) in the P2X7R gene (rs2393799, rs7958311, rs1718119, rs2230911, rs3751143) and two ER-α PvuII and XbaI polymorphisms were genotyped and analyzed. Single-gene variant analysis showed that the carriers of the CC genotype of P2X7R rs3751143 revealed an increased OP risk. Haplotype rs1718119G-rs2230911G-rs3751143C also appeared to be a significant 'risk' haplotype with OP. For the ER-α gene, no evidence of significant association of PvuII or XbaI polymorphism with OP risk was found. Moreover, there was a significant gene-gene interaction between P2X7R rs3751143 and ER-α PvuII; the cross-validation consistency was 10/10 and the testing accuracy was 0.5818 (P = 0.0107). A 1.67-fold-increased risk for OP was detected in individuals carrying the genotypes of AC or CC of rs3751143 and Pp or PP of PvuII compared to subjects with AA of rs3751143 and pp of PvuII. Our findings suggest an important association of the P2X7R rs3751143CC genotype and the rs1718119G-rs2230911G-rs3751143C haplotype with an increased OP risk. Also, the P2X7R rs3751143 and ER-α PvuII two-locus interaction confers a significantly high susceptibility to OP in Chinese postmenopausal women.


Assuntos
Povo Asiático/genética , Epistasia Genética , Receptor alfa de Estrogênio/genética , Predisposição Genética para Doença , Osteoporose Pós-Menopausa/genética , Polimorfismo Genético , Receptores Purinérgicos P2X7/genética , Estudos de Casos e Controles , Feminino , Frequência do Gene/genética , Haplótipos/genética , Humanos , Modelos Logísticos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único/genética , Fatores de Risco
11.
Menopause ; 25(3): 329-335, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29088017

RESUMO

OBJECTIVE: We conducted a case-control study to investigate the associations of functional single-nucleotide polymorphisms in the purinergic P2X7 receptor (P2X7R) gene (rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143) with obesity and overweight in a population of Chinese postmenopausal women. METHODS: Our study included 180 obese women, 179 overweight women, and 204 controls. All participants were genotyped at the P2X7R rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143 loci via allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism procedures. The relationships between P2X7R genetic polymorphisms and their associated haplotypes with obesity (body mass index [BMI] ≥30 kg/m] and overweight (25 kg/m ≤ BMI < 30 kg/m) were evaluated. RESULTS: Our results showed that P2X7R rs2230911G and rs1718119A were associated with an increased risk of obesity; in particular, both carriers of the rs2230911G allele and GG/(CG + GG) genotypes (G vs C, P < 0.001, odds ratio [OR] 2.87, 95% confidence interval [CI] 1.98-4.16; GG vs CC, P < 0.001, OR 8.76, 95% CI 3.29-23.35; CG + GG vs CC, P < 0.001, OR 2.54, 95% CI 1.63-3.95) and carriers of the rs17181191A allele and GA/(GA + AA) genotypes (A vs G, P < 0.001, OR 2.97, 95% CI 1.86-4.74; GA vs GG, P = 0.001, OR 2.72, 95% CI 1.55-4.79; GA + AA vs GG, P < 0.001, OR 3.05, 95% CI 1.79-5.19) were at a higher risk of obesity. No association with obesity or overweight was observed for the other three P2X7R polymorphisms (rs2393799, rs7958311, and rs3751143). Haplotype analysis indicated that P2X7R rs1718119A-rs2230911G-rs3751143C appeared to be a significant risk haplotype with obesity (P = 0.0005, OR 2.37, 95% CI 1.45-3.90). CONCLUSIONS: P2X7R functional genetic polymorphisms and their estimated haplotypes are associated with obesity in Chinese postmenopausal women.


Assuntos
Predisposição Genética para Doença , Obesidade/genética , Receptores Purinérgicos P2X7 , Alelos , Estudos de Casos e Controles , China , Estudos Transversais , Feminino , Frequência do Gene , Haplótipos , Humanos , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Pós-Menopausa , Fatores de Risco
12.
Purinergic Signal ; 13(3): 339-346, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28497417

RESUMO

Osteoporosis (OP) is a major public health problem worldwide. Genetic factors are considered to be major contributors to the pathogenesis of OP. The purinergic P2X7 receptor (P2X7R) has been shown to play a role in the regulation of osteoblast and osteoclast activity and has been considered as an important candidate gene for OP. A case-control study was performed to investigate the associations of functional single nucleotide polymorphisms (SNPs) in the P2X7R gene (rs2393799, rs7958311, rs1718119, rs2230911, and rs3751143) with susceptibility to OP in 400 Chinese OP patients and 400 controls. Results showed that rs3751143 was associated with OP; in particular, carriers of the C allele and CC/(AC + CC) genotypes were at a higher risk of OP, but no significant association of rs2230911, rs7958311, rs1718119, and rs2393799 with OP risk was observed. Analysis of the haplotypes revealed one haplotype (rs1718119G-rs2230911G-rs3751143C) that appeared to be a significant "risk" haplotype with OP. The rs3751143 polymorphism was associated with osteoclast apoptosis; ATP-induced caspase-1 activity of osteoclasts with AC and CC genotypes is lower than that of osteoclasts with AA genotype in vitro. The findings suggest that the P2X7R rs3751143 functional polymorphism might contribute to OP susceptibility in Chinese postmenopausal women.


Assuntos
Predisposição Genética para Doença , Osteoporose/genética , Pós-Menopausa/genética , Receptores Purinérgicos P2X7/genética , Povo Asiático , Estudos de Casos e Controles , Feminino , Frequência do Gene/genética , Genótipo , Humanos , Polimorfismo de Nucleotídeo Único/genética , Fatores Sexuais
13.
Zhongguo Dang Dai Er Ke Za Zhi ; 18(2): 117-22, 2016 Feb.
Artigo em Chinês | MEDLINE | ID: mdl-26903057

RESUMO

OBJECTIVE: To compare the epidemiological and clinical features of lower respiratory tract infection (LRTI) caused by influenza virus A (IVA) and influenza virus B (IVB) in children. METHODS: The clinical data of 366 children with LRTI caused by influenza virus (IV), who were hospitalized in Yuying Children′s Hospital of Wenzhou Medical University between 2010 and 2014, were analyzed retrospectively, and there were 272 cases caused by IVA and 94 cases caused by IVB. RESULTS: IV was mainly prevalent from December to March of the next year, with the predominance of IVA. There were small peaks of IVA prevalence in July or September every other year, and IVB was prevalent from December to March of the next year every other year. The children with LRTI caused by IVA alone had a significantly higher white blood cell (WBC) count and significantly higher percentages of children with increased WBC, abnormal serum sodium, and abnormal serum potassium than those caused by IVB alone (P<0.05). However, there were no significant differences in age, sex, underlying diseases, clinical manifestations, and co-infection rate with bacteria or atypical pathogens between the two groups (P>0.05). The rate of co-infection with respiratory syncytial virus (RSV) was significantly higher in the IVB group than in the IVA group (P<0.01). CONCLUSIONS: IVA is prevalent in winter and spring every year and has small peaks in summer every other year, while IVB is prevalent in winter and spring every other year. Compared with IVB, IVA causes more cases of increased WBC and electrolyte disturbance. The children infected with IVB are more likely to be co-infected with RSV. The children with LRTI caused by IVA and IVB have similar clinical manifestations.


Assuntos
Vírus da Influenza A/fisiologia , Vírus da Influenza B/fisiologia , Influenza Humana/virologia , Infecções Respiratórias/virologia , Criança , Pré-Escolar , China/epidemiologia , Feminino , Humanos , Lactente , Recém-Nascido , Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Vírus da Influenza B/genética , Vírus da Influenza B/isolamento & purificação , Influenza Humana/diagnóstico , Influenza Humana/epidemiologia , Masculino , Infecções Respiratórias/diagnóstico , Infecções Respiratórias/epidemiologia , Estudos Retrospectivos , Estações do Ano
14.
Analyst ; 140(21): 7154-9, 2015 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-26378690

RESUMO

The development of stable and reproducible methods for in vivo electrochemical monitoring of neurochemicals is of great physiological importance. In this study, we demonstrate ferricyanide-filled cylindrical carbon fiber microelectrodes (CFEs) of high stability and low polarized potential for in vivo electrochemical analysis. We first studied the voltammetric behavior of cylindrical CFEs by using a model system consisting of two separated cells each containing potassium ferricyanide (K3Fe(CN)6) or potassium ferrocyanide (K4Fe(CN)6). We observed that E1/2 values of the system were dependent on the ratio of the lengths of the cylindrical CFEs and of the concentrations of the redox species on both poles. Based on this property, we prepared the ferricyanide-backfilled cylindrical CFEs, and found that this kind of electrode exhibits a more stable current response and a lower polarized potential than the CFEs backfilled with KCl or Ru(NH3)6Cl3. Animal experiments with the ferricyanide-backfilled cylindrical CFEs demonstrate that this kind of electrode could be used for in vivo monitoring of neurochemical release with a high stability under some physiological conditions.


Assuntos
Carbono/química , Eletroquímica/instrumentação , Eletrodos , Ferricianetos/química , Microeletrodos , Animais , Química Encefálica , Fibra de Carbono , Eletroquímica/métodos , Masculino , Oxirredução , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos Testes
15.
Biochem Biophys Res Commun ; 392(1): 77-82, 2010 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-20059977

RESUMO

In yeast, TATA box-binding protein TBP can be delivered to protein-coding genes by direct interactions with two different coactivators: TFIID, which delivers TBP preferentially to TATA-less promoters, and SAGA, which strongly favors TATA box-containing promoters. Transcriptional activators of SAGA-dependant genes are characterized by prototypic acidic activation domains (ADs) that efficiently recruit SAGA, but not TFIID, to UAS elements even in the absence of a core promoter. In contrast to the well-studied acidic activation domains, little is known about the activation domains of activators of TFIID-dependent genes, even though these genes constitute more than 80% of eukaryotic protein-coding genes. The paradigm for TATA-less genes are the ribosomal protein genes (RPGs). Here we have identified the AD of the RPG activator Ifh1p and demonstrate that a minimal Ifh1 AD represents a new class of AD that significantly differs from acidic ADs in amino acid signature, relative coactivator affinities, and core promoter selectivity.


Assuntos
Regulação Fúngica da Expressão Gênica , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/genética , Transativadores/metabolismo , Ativação Transcricional , Sequência de Aminoácidos , Dados de Sequência Molecular , Regiões Promotoras Genéticas , Estrutura Terciária de Proteína , Proteínas de Saccharomyces cerevisiae/genética , TATA Box , Transativadores/genética
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