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1.
Environ Technol ; 42(8): 1225-1235, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31475875

RESUMO

A novel quantitative analysis method for cellulose fibre was developed to understand its behaviour in biological wastewater treatment and waste sludge processes. The method developed in this study was designed using Pseudomonas aeruginosa to remove it by dissolving all the organic components except cellulose from the sludge due to needing the solubilisation of bacteria occupied almost of sludge matrix and quantifying the amount of remaining cellulose. The results of this study indicated that a combined treatment process that employed 2,000 U/L protease, 2 M hydrogen peroxide, and 2 mM potassium hydroxide after pre-treatment for floc dispersion with an ultrasonic treatment at 26 W for 1 min resulted in a solubilisation of 96% of P. aeruginosa without losing the cellulose fibre. When it was applied to the cellulose fibre added in the sludge from a municipal wastewater treatment facility, 99.5% of the cellulose fibre was recovered by using the high-speed centrifuge.


Assuntos
Esgotos , Purificação da Água , Celulose , Eliminação de Resíduos Líquidos , Águas Residuárias/análise
2.
Environ Sci Technol ; 53(15): 9109-9117, 2019 Aug 06.
Artigo em Inglês | MEDLINE | ID: mdl-31276395

RESUMO

A tertiary polyamide membrane was synthesized using N,N'-dimethyl-m-phenylenediamine. The durability of this membrane to chlorination by hypochlorite treatment followed by sodium hydroxide treatment was examined, and then deterioration mechanisms were proposed. The tertiary polyamide membrane demonstrated better durability to free chlorine than a conventional secondary polyamide one; however, the former was deteriorated by hypochlorite for 24 h at 2000 ppm of free chlorine below pH 7.5. The salt rejection and permeation performance of the membrane were almost unchanged, and the least chlorination of the active layer occurred during hypochlorite treatment at pH 10. These results indicated that hypochlorous acid rather than hypochlorite ion was the free chlorine species that induced membrane deterioration. The deterioration became severe as chlorination progressed, resulting in collapse of the active layer below pH 7.5. Chlorination and hydrolysis of the model tertiary amide N-methylbenzanilide and Fourier transfer infrared spectroscopy of a deteriorated membrane showed that chlorination of the tertiary polyamide occurred via direct chlorination of the benzene bound to the amidic nitrogen. Silver ion probing of the deteriorated membrane revealed that amide bond scission occurred in the active layer, which might be related to the electron deficiency of the amidic nitrogen caused by chlorination of its benzene ring.


Assuntos
Nylons , Purificação da Água , Cloro , Ácido Hipocloroso , Membranas Artificiais , Osmose
3.
Mar Environ Res ; 148: 67-74, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31102904

RESUMO

Benthic invertebrates that inhabit the seafloor respond to anthropogenic and natural stresses, and are good indicators for assessing the benthic ecological status. We evaluated the ecosystem health of the Seto Inland Sea based on the multivariate AZTI Marine Biotic Index (M-AMBI), being its first application in a Japanese coastal sea with numerous endemic species. From the 415 locations studied, we were able to use M-AMBI in 384 sites (92.5% in all sites). The result revealed a statistically significant correlation among biotic indices including AMBI, M-AMBI, Richness, and H' (p < 0.01). Most of the physico-chemical parameters of the sediment (water content, total organic carbon (TOC) content, sulfide content, mud content, and oxidation-reduction potential (ORP)) were significantly correlated with each other excluding sediment temperature. The M-AMBI was significantly correlated with physico-chemical variables including water content, TOC content, sulfide content, and ORP. We found that the sites classified into the organically enriched cluster, and having high contents of TOC, mud, and sulfide and negative ORP, corresponded with sites that had significantly low M-AMBI values (bad-poor ecological status). Conversely, sites in the unpolluted sandy cluster were assigned high M-AMBI values (high-good ecological status). Therefore, M-AMBI would be a useful biotic index in Japanese coasts due to the representation of the comprehensive sediment quality.


Assuntos
Saúde Ambiental , Monitoramento Ambiental , Sedimentos Geológicos/química , Invertebrados/química , Animais , Carbono/química , Japão , Biologia Marinha
4.
Water Sci Technol ; 73(12): 2978-85, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27332844

RESUMO

A novel method was proposed to determine biofouling potential by direct analysis of a reverse osmosis (RO) membrane through fluorescence intensity analysis of biofilm formed on the membrane surface, thereby incorporating fouling tendencies of both feedwater and membrane. Evaluation of the biofouling potential on the RO membrane was done by accelerated biofilm formation through soaking of membranes in high biofouling potential waters obtained by adding microorganisms and glucose in test waters. The biofilm formed on the soaked membrane was quantified by fluorescence intensity microplate analysis. The soaking method's capability in detecting biofilm formation was confirmed when percentage coverage obtained through fluorescence microscopy and intensity values exhibited a linear correlation (R(2) = 0.96). Continuous cross-flow experiments confirmed the ability and reliability of the soaking method in giving biofouling potential on RO membranes when a good correlation (R(2) = 0.87) between intensity values of biofilms formed on the membrane during soaking and filtration conditions was obtained. Applicability of the test developed was shown when three commercially available polyamide (PA) RO membranes were assessed for biofouling potential. This new method can also be applied for the determination of biofouling potential in water with more than 3.6 mg L(-1) easily degradable organic carbon.


Assuntos
Fenômenos Fisiológicos Bacterianos , Biofilmes , Incrustação Biológica/prevenção & controle , Filtração/métodos , Purificação da Água/métodos , Filtração/instrumentação , Reprodutibilidade dos Testes , Purificação da Água/instrumentação
5.
Bull Environ Contam Toxicol ; 94(6): 796-800, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25917847

RESUMO

Variation, run-off and degradation characteristics of the insecticide dinotefuran, (EZ)-(RS)-1-methyl-2-nitro-3-(tetrahydro-3-furyl-methyl)guanidine, in water and soil from two paddy fields after aerial application was investigated as well as in river water. Maximum concentrations of dinotefuran were 290 and 720 µg/L in the two paddy waters, 25 and 28 µg/kg dry in the two paddy soils, and 10 µg/L in the river water. Runoff ratios of dinotefuran from the paddy fields were calculated as 14%-41%. Mean half-lives of dinotefuran were 5.4 days in the paddy water and 12 days in the paddy soil. Results obtained in this study are important for the evaluation of the actual behavior of dinotefuran in paddy fields and rivers.


Assuntos
Biodegradação Ambiental , Guanidinas/metabolismo , Nitrocompostos/metabolismo , Rios/química , Poluentes Químicos da Água/análise , Agricultura , Ar , Água Doce , Neonicotinoides , Solo , Água , Movimentos da Água
6.
J Hazard Mater ; 268: 150-5, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24491439

RESUMO

The performance of a ferric ion mediated photochemical process for perfluorooctanoic acid (PFOA) decomposition in strongly acidic conditions of pH 2.0 was evaluated in comparison with those in weakly acidic conditions, pH 3.7 or pH 5.0, based on iron species composition and ferric ion regeneration. Complete decomposition of PFOA under UV irradiation was confirmed at pH 2.0, whereas perfluoroheptanoic acid (PFHpA) and other intermediates were accumulated in weakly acidic conditions. Iron states at each pH were evaluated using a chemical equilibrium model, Visual MINTEQ. The main iron species at pH 2.0 is Fe(3+) ion. Although Fe(3+) ion is consumed and is transformed to Fe(2+) ion by photochemical decomposition of PFOA and its intermediates, the produced Fe(2+) ion will change to Fe(3+) ion to restore chemical equilibrium. Continuous decomposition will occur at pH 2.0. However, half of the iron cannot be dissolved at pH 3.7. The main species of dissolved iron is Fe(OH)(2+). At pH 3.7 or higher pH, Fe(3+) ion will only be produced from the oxidation of Fe(2+) ion by hydroxyl radical produced by Fe(OH)(2+) under UV irradiation. These different mechanisms of Fe(3+) regeneration that prevail in strongly and weakly acidic conditions will engender different performances of the ferric ion.


Assuntos
Caprilatos/isolamento & purificação , Compostos Férricos/química , Fluorocarbonos/isolamento & purificação , Raios Ultravioleta , Poluentes Químicos da Água/isolamento & purificação , Purificação da Água/métodos , Caprilatos/química , Caprilatos/efeitos da radiação , Fluorocarbonos/química , Fluorocarbonos/efeitos da radiação , Concentração de Íons de Hidrogênio , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/efeitos da radiação
7.
Bull Environ Contam Toxicol ; 89(4): 770-4, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22918321

RESUMO

The characteristic distributions of 12 metals (Al, Ti, Cr, Mn, Fe, Co, Ni, Cu, Zn, Sr, Cd and Pb) were investigated in surface sediments from a small river (Niitsu River) flowing through both urban and agricultural areas by comparison with those from the upper main stream (Nodai River). Among the investigated metals, the mean concentrations of Al, Cr, Fe, Zn, Cd and Pb in the Niitsu River were significantly higher than those in the Nodai River. The investigated sites can be characterized by the principal components 1-3.


Assuntos
Sedimentos Geológicos/química , Metais/análise , Rios/química , Poluentes Químicos da Água/análise , Agricultura/estatística & dados numéricos , Cidades/estatística & dados numéricos , Monitoramento Ambiental , Japão , Poluição Química da Água/estatística & dados numéricos
8.
Bull Environ Contam Toxicol ; 89(5): 985-9, 2012 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-22914901

RESUMO

Behavior of the herbicide pyrazolynate, 4-(2,4-dichlorobenzoyl)-1,3-dimethylpyrazol-5-yl p-toluenesulfonate, in paddy water and soil after application to paddy fields was investigated to evaluate the hydrolyzation to destosyl pyrazolynate (DTP), 4-(2,4-dichlorobenzoyl)-1,3-dimethyl-5-hydroxypyrazole. The respective maximum concentrations of pyrazolynate and DTP were 440-1,240 and 200-260 µg/L, respectively, in the paddy water, and 610-860 µg/kg dry and 460-730 µg/kg dry in the paddy soil. The applied pyrazolynate was drained from the paddy fields as DTP. The runoff ratios of DTP from the paddy fields were calculated as 19 % ± 14 %. The respective mean values of the half-lives of pyrazolynate and DTP were 0.87 ± 0.091 and 17 ± 1.4 days in the paddy water and 2.2 ± 0.70 and 26 ± 2.1 days in the paddy soil, respectively.


Assuntos
Monitoramento Ambiental , Herbicidas/análise , Modelos Químicos , Pirazóis/análise , Poluentes Químicos da Água/análise , Agricultura , Oryza
9.
Bull Environ Contam Toxicol ; 89(4): 764-9, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22907653

RESUMO

Characteristic distributions of Al, Mn, Fe, Ni, Zn, and Pb were investigated in the surface sediments of a small river (Niitsu River) flowing through both urban and agricultural areas, along with comparison with those from the upper main stream (Nodai River). The mean compositions of the most mobile metals were ordered as Zn = Mn > Ni = Pb = Fe > Al in the Niitsu River. They were Mn = Zn = Pb = Fe > Ni = Al in the Nodai River. Mn, Fe, Ni, and Zn in the Niitsu River showed higher compositions of mobile (2.9%-36%) and oxidizable (6.6%-16%) phases than those in the Nodai River. The Ni and Zn in the Niitsu River also had higher reducible phase composition (15% and 16%, respectively). In the Niitsu River, Pb had the higher oxidizable composition (29%). Over 90% of Al was in the lithogenic phase in the two rivers.


Assuntos
Agricultura/estatística & dados numéricos , Sedimentos Geológicos/química , Metais/análise , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Japão , Rios/química , Poluição Química da Água/estatística & dados numéricos
10.
Bull Environ Contam Toxicol ; 89(1): 176-80, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22476350

RESUMO

Variations in concentrations of herbicide bromobutide (RS)-2-bromo-N-(α,α-dimethylbenzyl)-3,3-dimethylbutyramide, and its metabolite bromobutide-debromo, N-(α,α-dimethylbenzyl)-3,3-dimethylbutyramide were investigated in soils from three paddy fields used for rice farming at 24 weeks after application. The bromobutide concentration was maximum within 24 h after application. That of bromobutide-debromo was maximum within 5-7 days of application. Each gradually decreased to below detection limits at 12-22 weeks after application. Bromobutide was detected up to 76-104 days after application in the paddy soils, whereas bromobutide-debromo was detected up to 125 days after application. The bromobutide composition was higher than 90 % within 6 days of application, decreasing to less than 5 % by 125 days of application. The decrease of bromobutide amount in the soil was inferred as the first-order reaction. The bromobutide half-life was calculated as 12-21 days (16 days mean) during 18-104 days following application.


Assuntos
Agricultura , Herbicidas/análise , Hidrocarbonetos Bromados/análise , Solo/química , Poluentes Químicos da Água/análise , Monitoramento Ambiental , Meia-Vida , Oryza
11.
J Colloid Interface Sci ; 359(2): 407-12, 2011 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-21536298

RESUMO

Magnetic carbonaceous materials were produced by carbonization of a cation exchange resin loaded with ferrous or ferric iron and activation using sieved oyster shell as the activation agent. The magnetic carbonaceous material with the maximum magnetic flux density on every axis (ESS-1) was obtained from the ferric-loaded resin by carbonization at 700°C, followed by activation with the oyster shell at 900°C, and magnetization. A separate step of carbonization and activation appears to cause more of a reduction reaction of Fe to form γ-Fe(2)O(3). The Fe compound in the magnetic carbonaceous material was identified from the XRD pattern as mainly γ-Fe(2)O(3). The magnetic flux density on every axis increased linearly as the amount of the oyster shell increased. Moreover, the adsorption ability of the products was evaluated for pesticides and metal ions. Both ESS-1 and a carbonaceous material obtained from the resin without ferric ion (RC) appear to have the highest adsorption ability for lead. Furthermore, the adsorption ability of ESS-1 might decrease by blockages of the pores with the loaded Fe compounds.


Assuntos
Ferro/química , Metais/isolamento & purificação , Ostreidae/química , Praguicidas/isolamento & purificação , Adsorção , Animais , Magnetismo
12.
Biosci Biotechnol Biochem ; 74(9): 1951-2, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-20834148

RESUMO

Two serotonin derivatives, N,N-dimethylserotonin 5-O-ß-glucoside (1a) and N-methylserotonin 5-O-ß-glucoside (1b) were isolated from immature seeds of Zanthoxylum piperitum. Their structures were determined by multi-step conversion reactions and spectroscopic analyses. Immature seeds of Z. piperitum contained extremely high levels of compounds 1a and 1b of approximately 0.29% and 0.15% (w/w), respectively.


Assuntos
Bufotenina/isolamento & purificação , Sementes/química , Serotonina/análogos & derivados , Zanthoxylum/química , Glucosídeos , Estrutura Molecular , Serotonina/isolamento & purificação , Antagonistas da Serotonina/isolamento & purificação , Análise Espectral
13.
Pediatr Neurol ; 42(4): 277-9, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20304332

RESUMO

The aim of this study was to determine whether seizure susceptibility due to antihistamines is provoked in patients with febrile seizures. The study population comprised 14 patients with simple febrile seizures and 35 patients with complex febrile seizures. Detailed clinical manifestations were compared between patients with and without administration of antihistamine. The time from fever detection to the seizure onset was significantly shorter in the antihistamine group than that in the nonantihistamine group, and the duration of seizures was significantly longer in the antihistamine group than that in nonantihistamine group. Interleukin-1beta is thought to be associated with causing febrile seizures via its dual role as a pyrogen and convulsant substance. Moreover, interleukin-1beta may activate the turnover of hypothalamic neural histamine. These considerations, along with the present results, suggest that the depletion of hypothalamic neuronal histamine induced by antihistamines may increase neuronal excitability, thereby increasing seizure susceptibility in patients with febrile seizures.


Assuntos
Antagonistas dos Receptores Histamínicos/efeitos adversos , Convulsões Febris/fisiopatologia , Convulsões/induzido quimicamente , Suscetibilidade a Doenças , Exantema Súbito/fisiopatologia , Feminino , Febre/tratamento farmacológico , Antagonistas dos Receptores Histamínicos/uso terapêutico , Humanos , Lactente , Influenza Humana/fisiopatologia , Masculino , Estudos Retrospectivos , Fatores de Tempo
14.
Congenit Anom (Kyoto) ; 48(2): 97-100, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18452492

RESUMO

A neonatal case of provisional neurocutaneous melanosis presenting with lissencephaly is reported. Several congenital nevi were observed on the trunk and extremities of the infant, including a giant congenital hairy nevus over the skull. Brain magnetic resonance imaging revealed a marked ventricular dilatation with pachygyria and an absent corpus callosum; however, an injection of gadolinium did not demonstrate any enhanced lesions. Histopathological investigations by a brain biopsy showed a disorganized and anomalous embryonic cerebral architecture, suggesting lissencephaly. The detailed mechanism of this combined pathology is difficult to explain; however, a developmental disturbance was suggested to be present in both the neural crest cells and the neuroepithelial cells, resulting in the development of neurocutaneous melanosis accompanied with lissencephaly.


Assuntos
Agenesia do Corpo Caloso , Lisencefalia/complicações , Nevo Pigmentado/congênito , Humanos , Recém-Nascido , Lisencefalia/diagnóstico , Imageamento por Ressonância Magnética , Masculino , Nevo Pigmentado/complicações
15.
Angiology ; 58(5): 636-9, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17906282
16.
Pediatr Neurol ; 35(1): 38-41, 2006 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16814083

RESUMO

This study investigates the clinical features of epilepsy in 20 patients with brain malformation. Epileptic seizures were recognized in 15 patients, 12 of whom had their first seizure by 1 year of age. Partial seizure was the initial seizure type in 10 patients. Epileptic seizures were controlled in only four patients. Patients with holoprosencephaly and lissencephaly had seizure onset by 3 months of age, resulting in the most severe neurologic outcome. Only two patients with porencephaly had epileptic seizures, and in one of those patients the seizures were well controlled. A wide variety of clinical features of epilepsy in patients with brain malformation was found. More immature anomalous brain lesions may be associated with an enhanced capacity of epilepsy and resultant refractory seizures.


Assuntos
Encéfalo/anormalidades , Encéfalo/crescimento & desenvolvimento , Epilepsia/patologia , Adolescente , Adulto , Criança , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Malformações do Sistema Nervoso/patologia
18.
Brain Res ; 1089(1): 55-66, 2006 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-16638609

RESUMO

Primary microcephaly can be accompanied by numerous migration anomalies. This experiment was undertaken to examine the pathogenesis of gray matter heterotopia and microcephaly that is produced after administering cytosine arabinoside (Ara-C) to mice. Pregnant mice were intraperitoneally injected with Ara-C at 30 mg/kg body weight on days 13.5 and 14.5 of gestation, and then their offspring were examined. On embryonic day 15.5, in the ventricular zone of the cingulate cortex, the neuroepithelial cells lacked BrdU immunoreactivity. Nestin-immunoreactive radial glial fibers and calretinin-positive subplate fibers were disrupted. TUNEL reaction was remarkable throughout the cerebral hemisphere. Subcortical heterotopia in the cingulate cortex and subependymal nodular heterotopia in the dorsolateral part of the lateral ventricles became detectable by the first day after birth. Thirty-two days after birth, microcephaly was apparent; subcortical heterotopia was observed to have increased in size while it was still located in the frontal and cingulate cortices. This experiment demonstrated that Ara-C induces neuronal apoptosis throughout the cerebral hemisphere. The immunohistochemical characteristics in the gray matter heterotopia suggest that both the subcortical and the subependymal heterotopias were formed by neurons originally committed to the neocortex. We conclude that the gray matter heterotopia that accompanies the microcephaly was produced by a disturbance of radial, tangential, and interkinetic neuronal migrations due to the toxicity of Ara-C in the immature developing brain.


Assuntos
Córtex Cerebral/anormalidades , Córtex Cerebral/efeitos dos fármacos , Coristoma/induzido quimicamente , Citarabina/efeitos adversos , Microcefalia/induzido quimicamente , Malformações do Sistema Nervoso/induzido quimicamente , Animais , Animais Recém-Nascidos , Antimetabólitos Antineoplásicos/efeitos adversos , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Biomarcadores/metabolismo , Bromodesoxiuridina , Calbindina 2 , Diferenciação Celular/efeitos dos fármacos , Diferenciação Celular/fisiologia , Movimento Celular/efeitos dos fármacos , Movimento Celular/fisiologia , Proliferação de Células/efeitos dos fármacos , Córtex Cerebral/fisiopatologia , Coristoma/diagnóstico , Coristoma/fisiopatologia , Modelos Animais de Doenças , Camundongos , Camundongos Endogâmicos ICR , Microcefalia/diagnóstico , Microcefalia/fisiopatologia , Proteínas Associadas aos Microtúbulos/metabolismo , Degeneração Neural/induzido quimicamente , Degeneração Neural/fisiopatologia , Malformações do Sistema Nervoso/diagnóstico , Malformações do Sistema Nervoso/fisiopatologia , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Proteína G de Ligação ao Cálcio S100/metabolismo , Células-Tronco/efeitos dos fármacos , Células-Tronco/metabolismo , Células-Tronco/patologia
19.
Brain Dev ; 28(3): 162-9, 2006 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-16466882

RESUMO

The continuous performance test (CPT) is designed to measure sustained attention quantitatively. Several CPTs are used clinically. We have made changes to the conventional type of visual CPT, by displaying auditory and visual noise along with target or non-target stimuli. By influencing the recognition of the subjects in this way, the changes were intended to increase the sensitivity of detection of inattention and impulsiveness, to make CPT more useful for diagnosis, and to examine the effect of noise on AD/HD children during CPT performance. Its usefulness for AD/HD diagnosis and the reaction of AD/HD children to noise were examined using newly developed computer software. Using this CPT analysis, a significant difference was observed in all measurements, except mean reaction time, between the control and AD/HD groups, showing that it was useful as a supplementary diagnostic method for AD/HD, and was more useful in the younger age group than in the older age group, as the same for conventional CPTs. As compared to no-noise sessions, commission and omission errors both increased significantly in auditory and visual noise sessions. Thus, analyzing the changes in measurements during noise sessions will improve the diagnosis of inattention and combined AD/HD subtypes. Furthermore, it was suggested that analysis of the effects of noise on AD/HD children will benefit their handling in an educational environment. Since omission errors were decreased in AD/HD children by noise during the CPT performance as compared to the control group, noise may induce attention in AD/HD children. The present study presents new findings on the responses to noise of AD/HD children during the CPT.


Assuntos
Estimulação Acústica , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Atenção , Ruído , Estimulação Luminosa , Envelhecimento , Criança , Humanos , Testes Neuropsicológicos , Valores de Referência , Software
20.
Exp Neurol ; 186(1): 89-98, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-14980813

RESUMO

Hypoxic-ischemic (H-I) injury to neonatal brains can cause a life-long neuronal deficit because of increased susceptibility in the neonatal period. Excitotoxicity due to overstimulation of the N-methyl-d-aspartate receptor (NMDAR) is assumed to be the basis of the injury. However, the ontogenic profile of the susceptibility does not directly correlate with the levels of NMDAR expression. Platelet-derived growth factor B-chain (PDGF-B) has been reported to protect neurons by suppressing the NMDA-evoked current and translocating the glutamate transporter to the cell membrane. Thus, we assessed the relationship between the susceptibility to H-I injury and the expression of PDGF-B in neonatal rat brain. PDGF-B infusion before and after an intrastriatal NMDA injection significantly reduced the size of the lesions in 7-day-old rats, when they are most susceptible and the neuronal expression of PDGF-B is low. Fourteen-day-old neonatal rats were found to be resistant to NMDA injury, even though NMDARs are expressed at high levels in the brain at this age. Inhibition of PDGF-B protein synthesis by antisense oligodeoxynucleotides increased the size of the NMDA-induced lesions up to 6-fold at postnatal day 14, when PDGF-B is expressed at high levels in neurons. These data suggest that PDGF-B is an important physiological modulator of NMDAR excitability in the developing brain, and that the balance between the expression of NMDAR and PDGF-B partly determines the ontogenic susceptibility to brain injury. Enhancement of the PDGF-B/receptor signal pathway might rescue neonatal brains at risk of H-I injury.


Assuntos
Encéfalo/efeitos dos fármacos , Agonistas de Aminoácidos Excitatórios/toxicidade , N-Metilaspartato/toxicidade , Proteínas Proto-Oncogênicas c-sis/metabolismo , Envelhecimento , Análise de Variância , Animais , Animais Recém-Nascidos , Encéfalo/crescimento & desenvolvimento , Encéfalo/patologia , Células COS , Chlorocebus aethiops , DNA/metabolismo , Suscetibilidade a Doenças , Interações Medicamentosas , Immunoblotting/métodos , Imuno-Histoquímica/métodos , Oligorribonucleotídeos Antissenso/farmacologia , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Transfecção
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