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1.
Virus Genes ; 60(3): 309-313, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38491264

RESUMO

Adenoviruses (AdVs) have been detected in a wide variety of animals. To date, eight types of AdVs in sheep and two types in goats have been identified, which belong to two distinct genera, Mastadenovirus and Atadenovirus. Typically, the term pneumo-enteritis is used to describe adenovirus-induced disease in small ruminants, which has been associated with both enteric and respiratory symptoms of varying severity. The aim of this study was to detect and identify AdVs of small ruminants belonging to the genera Mastadenovirus and Atadenovirus. For this purpose, diagnostic samples (47 lung, 27 intestine, and two pooled tissue samples including intestine and lung) from 49 small ruminants (39 sheep and 10 goats) were used. Following the viral DNA extraction, PCR was carried out by using the primers targeting the hexon gene in order to detect both mast- and atadenoviruses. Sequencing the amplified fragments revealed the presence of three types of ovine adenovirus (OAdV): OAdV-3, OAdV-4, and OAdV-8. Specifically, OAdV-3 was detected in two sheep and a goat while OAdV-4 and OAdV-8 were found in only one sheep each. There is still limited data on the interaction between the viruses in different adenovirus genera and the detected disease, as well as the genetic diversity of adenoviruses, especially in small ruminants. In conclusion, the detection of AdVs in lung and intestinal tissues of small ruminants in this study suggests that these viruses may have contributed to the disease and/or predisposed to other agents.


Assuntos
Infecções por Adenoviridae , Doenças das Cabras , Cabras , Mastadenovirus , Filogenia , Doenças dos Ovinos , Animais , Cabras/virologia , Ovinos/virologia , Doenças dos Ovinos/virologia , Doenças das Cabras/virologia , Infecções por Adenoviridae/veterinária , Infecções por Adenoviridae/virologia , Mastadenovirus/genética , Mastadenovirus/isolamento & purificação , Mastadenovirus/classificação , Turquia , DNA Viral/genética , Análise de Sequência de DNA , Atadenovirus/genética , Atadenovirus/isolamento & purificação , Atadenovirus/classificação , Pulmão/virologia , Adenoviridae/genética , Adenoviridae/isolamento & purificação , Adenoviridae/classificação , Adenoviridae/patogenicidade
2.
Toxicol Mech Methods ; 34(5): 484-494, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38223921

RESUMO

The new technological applications of nickel (Ni) raise concerns over its harmful effects on the environment and human health. Pomiferin isolated from Osage orange is evaluated in in vitro and in vivo laboratory bioassays. This study focused the effects of pomiferin on Ni-caused hepatic injury and its underlying mechanisms. With this aim, Sprague-Dawley rats received 10 mg/kg nickel chloride (NiCl2) for 7 d by intraperitoneal injections. Pomiferin was given orally once a day at different doses (75, 150, and 300 mg/kg) for 20 d after exposure to NiCl2. Animals were anesthetized and livers were carefully collected to evaluate oxidative stress, inflammation, vascular injury, and hepatic function. Also, immunofluorescence analysis of apoptosis and DNA damage was performed on rat hepatic tissues. NiCl2 increased MDA production while reducing SOD, CAT, and GPx activity. NiCl2 induced the production of inflammatory cytokines and also platelet activation in hepatic tissue. Moreover, there were significant increases in AST, ALT, and LDH levels. NiCl2 also caused significant pathological changes in hepatic. Additionally, it remarkably induced up-regulations of apoptotic marker and 8-OHdG expressions by immunofluorescence labeling in liver cells. Whereas, pomiferin significantly attenuated lipid peroxidation and increased antioxidant defense system in liver. Also, the use of pomiferin prevented deregulated inflammatory process by signaling pathways nuclear factor kappa B (NFκB)/COX-2/TNF-α/IL-1ß/IL-6. In addition, pomiferin diminished histopathologic evidence of hepatic toxicity and significantly lower expressions of caspase 3 and 8-OHdG were observed in liver cells. Pomiferin seems to counteract the deleterious effects of NiCl2 on hepatic tissue through different cellular and signaling mechanisms.


NiCl2 induced the production of inflammatory cytokines and also platelet activation in hepatic tissue.NiCl2 increased MDA production while reducing SOD, CAT, and GPx activity.NiCl2 induced the production of inflammatory cytokines and also platelet activation in hepatic tissue.NiCl2 caused significant pathological changes in the liver and also up-regulation of apoptotic marker and 8-OHdG expressions by immunofluorescence staining.Pomiferin attenuated lipid peroxidation and increased antioxidant defense system in liver.The use of pomiferin prevented deregulated inflammatory process by signaling pathways nuclear factor kappa B (NFκB)/COX-2/TNF-α/IL-1ß/IL-6.Pomiferin diminished histopathologic evidence of hepatic toxicity and significantly lower expressions of caspase 3 and 8-OHdG were observed in liver cells.Pomiferin seems to counteract the deleterious effects of NiCl2 on hepatic tissue through different cellular and signaling mechanisms and thus can be used as a therapeutic practice against metal toxicity.


Assuntos
Apoptose , Doença Hepática Induzida por Substâncias e Drogas , Fígado , Níquel , Estresse Oxidativo , Ratos Sprague-Dawley , Transdução de Sinais , Animais , Níquel/toxicidade , Doença Hepática Induzida por Substâncias e Drogas/patologia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Induzida por Substâncias e Drogas/prevenção & controle , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Transdução de Sinais/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/patologia , Fígado/metabolismo , Masculino , Apoptose/efeitos dos fármacos , Benzopiranos/farmacologia , Antioxidantes/farmacologia , Ratos , Dano ao DNA/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos
3.
Arch. argent. pediatr ; 119(2): 106-113, abril 2021. tab
Artigo em Inglês, Espanhol | LILACS, BINACIS | ID: biblio-1151490

RESUMO

Introducción. En estudios anteriores, el uso excesivo o la exposición temprana a pantallas se asoció con atención deficiente, falta de control de la conducta, retraso del lenguaje y déficit en la función ejecutiva. El objetivo de este estudio fue investigar la relación entre el tiempo de uso de pantallas y la regulación emocional, que afecta las relaciones sociales de los niños de 2 a 5 años.Población y métodos. Estudio descriptivo transversal en un hospital universitario del 1.º de enero al 1.º de marzo de 2018. Se incluyó a madres de niños sanos de 2 a 5 años con un uso de pantallas inferior a 1 hora o superior a 4 horas. A quienes aceptaron participar se les administró una encuesta estructurada y la Emotion Regulation Checklist para padres.Resultados. De los 240 niños participantes, 98 (el 40,8 %) tenían un uso de pantallas ≥ 4 horas. Ser cuidado por la madre, tener 12 meses o más durante la primera exposición y no estar acompañado por los padres al usarlas se asociaron con ≥ 4 horas de uso de pantallas (p = 0,002; p = 0,002; p = 0,012, respectivamente). La proporción de participantes con una puntuación alta de labilidad/negatividad (L/N) fue significativamente mayor entre los niños con ≥ 4 horas de uso de pantallas y que no estaban acompañados por sus padres al usarlas (p = 0,004; p = 0,033, respectivamente).Conclusiones. Este estudio determinó que un uso excesivo de pantallas se asocia con labilidad emocional durante esta etapa temprana de la infancia.


Introduction. Previous studies have found that excessive screen time or early screen exposure is associated with poor attention, lack of behavioral control, delayed language and deficit in executive functions. The aim of this study was to investigate the relationship between screen time and emotion regulation skills, which is one of the important life components affecting the social relations of children aged 2 to 5 years.Population and methods.This cross-sectional descriptive study was carried out in a university hospital between January 1, 2018 and March 1, 2018. Mothers of healthy children aged 2-5 years with a daily screen time of less than 1 hour or over 4 hours were included in the study. A structured survey and the Emotion Regulation Checklist for parents were applied to the mothers who agreed to participate.Results. Of 240 children participating in the study, 98 (40.8 %) had ≥4 hours of screen time. Caring by mother, age at first screen exposure 12 months and older, not co-viewing with parents were found to be associated with ≥ 4 hours of screen time (p = 0.002, p = 0.002, p = 0.012, respectively). The ratio of participants with high-lability/negativity (L/N) score was significantly higher in children with screen time of ≥ 4 hours and not co-viewing with parents (p = 0.004, p = 0.033, respectively).Conclusions. This study investigating the relationship between the emotion regulation skill and screen time revealed that excessive screen time is associated with emotional lability in this early childhood period.


Assuntos
Humanos , Masculino , Feminino , Pré-Escolar , Tempo de Tela , Regulação Emocional , Turquia , Epidemiologia Descritiva , Estudos Transversais , Inquéritos e Questionários , Sintomas Afetivos/psicologia , Relações Interpessoais
4.
J Cancer Res Ther ; 15(1): 231-236, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30880783

RESUMO

AIM: The effect of acetylsalicylic acid (ASA) on thiol levels was studied in a rat model of azaserine carcinogenesis. MATERIALS AND METHODS: ASA and azaserine were applied to the animals to research changes in cellular sulfhydryl (-SH) content and variations in free and protein-bound molecules containing the -SH group. Such effects in rats injected with azaserine were investigated at low (200 ppm) and high (400 ppm) concentrations of ASA over a relatively short (6 months) and a relatively long (12 months) period. RESULTS: Changes in the hepatic, pancreatic, and renal -SH contents were also determined. CONCLUSION: Compared to the other tissues studied, the liver contained the highest levels of both free and protein-bound -SH.


Assuntos
Anti-Inflamatórios não Esteroides/administração & dosagem , Aspirina/administração & dosagem , Azasserina/toxicidade , Carcinógenos/toxicidade , Neoplasias/prevenção & controle , Animais , Relação Dose-Resposta a Droga , Humanos , Rim/química , Rim/efeitos dos fármacos , Rim/patologia , Fígado/química , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Neoplasias/induzido quimicamente , Neoplasias/patologia , Neoplasias Experimentais/induzido quimicamente , Neoplasias Experimentais/patologia , Neoplasias Experimentais/prevenção & controle , Pâncreas/química , Pâncreas/efeitos dos fármacos , Pâncreas/patologia , Ratos , Ratos Wistar , Compostos de Sulfidrila/análise , Resultado do Tratamento
5.
Angew Chem Int Ed Engl ; 55(8): 2875-8, 2016 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-26799149

RESUMO

The photosensitized generation of singlet oxygen within tumor tissues during photodynamic therapy (PDT) is self-limiting, as the already low oxygen concentrations within tumors is further diminished during the process. In certain applications, to minimize photoinduced hypoxia the light is introduced intermittently (fractional PDT) to allow time for the replenishment of cellular oxygen. This condition extends the time required for effective therapy. Herein, we demonstrated that a photosensitizer with an additional 2-pyridone module for trapping singlet oxygen would be useful in fractional PDT. Thus, in the light cycle, the endoperoxide of 2-pyridone is generated along with singlet oxygen. In the dark cycle, the endoperoxide undergoes thermal cycloreversion to produce singlet oxygen, regenerating the 2-pyridone module. As a result, the photodynamic process can continue in the dark as well as in the light cycles. Cell-culture studies validated this working principle in vitro.


Assuntos
Luz , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Oxigênio Singlete/química , Espectroscopia de Prótons por Ressonância Magnética
6.
Blood Cells Mol Dis ; 50(1): 1-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22824382

RESUMO

The main objective of the present study was to investigate if vanadate is extruded from the cells in a glutathione dependent manner resulting in the appearance of extracellular glutathione and complexes of glutathione with vanadium. Vanadate significantly depleted intracellular non-protein sulfhydryl (NPSH) levels in a time- and concentration-dependent manner. The intracellular NPSH level was decreased to 0.0 ± 0.0 µmol/ml erythrocyte when exposed to 10 mM of vanadate for 4h. Extracellular NPSH level was increased concomitantly with the intracellular decrease and reached to 0.1410 ± 0.005 µmol/ml erythrocyte in 4h. Intracellular decrease and extracellular increase in NPSH levels were significantly inhibited in the presence of DIDS, a chloride-bicarbonate exchanger which also mediates phosphate and arsenate transport in erythrocytes. In parallel with the increase in extracellular NPSH levels, significant increases in extracellular glutathione levels were detected following exposure to vanadate. Extracellular glutathione levels reached to 0.0150 ± 0.0.001, 0.0330 ± 0.001, and 0.0576 ± 0.002 µmol/ml erythrocyte with 1, 5, and 10 mM of vanadate respectively. Dimercaptosuccinic acid treatment of supernatants significantly increased the glutathione levels measured in the extracellular media. Utilization of MK571 an MRP inhibitor decreased the rate of glutathione efflux from erythrocytes suggesting a role for this membrane transporter in the process. A known methylation inhibitor periodate oxidized adenosine decreased the rate of glutathione efflux from erythrocytes. This observed decrease in extracellular GSH levels suggests that GSH release partly requires a proper cellular methylation process and that part of GSH detected in the extracellular media may arise from GSH-vandium complexes. The results of the present study indicate that human erythrocyte efflux glutathione in reduced free form and in conjugated form/s that can be recovered with dimercaptosuccinic acid when exposed to vanadate.


Assuntos
Eritrócitos/metabolismo , Glutationa/metabolismo , Vanadatos/farmacologia , Ácido 4,4'-Di-Isotiocianoestilbeno-2,2'-Dissulfônico/farmacologia , Adenosina/análogos & derivados , Adenosina/farmacologia , Transporte Biológico/efeitos dos fármacos , Células Cultivadas , Antiportadores de Cloreto-Bicarbonato/antagonistas & inibidores , Antiportadores de Cloreto-Bicarbonato/metabolismo , Relação Dose-Resposta a Droga , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Humanos , L-Lactato Desidrogenase/metabolismo , Metilação/efeitos dos fármacos , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Propionatos/farmacologia , Quinolinas/farmacologia , Succímero/farmacologia , Compostos de Sulfidrila/metabolismo
7.
Biol Trace Elem Res ; 150(1-3): 451-9, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22890881

RESUMO

The objective of the present study was to investigate if arsenic exposure results in glutathione efflux from human erythrocytes. Arsenite significantly depleted intracellular nonprotein thiol level in a time- and concentration-dependent manner. The intracellular nonprotein thiol level was decreased to 0.767 ± 0.0017 µmol/ml erythrocyte following exposure to 10 mM of arsenite for 4 h. Extracellular nonprotein thiol level was increased concomitantly with the intracellular decrease and reached to 0.481 ± 0.0005 µmol/ml erythrocyte in 4 h. In parallel with the change in extracellular nonprotein thiol levels, significant increases in extracellular glutathione levels were detected. Extracellular glutathione levels reached to 0.122 ± 0.0013, 0.226 ± 0.003, and 0.274 ± 0.004 µmol/ml erythrocyte with 1, 5, and 10 mM of arsenite, respectively. Dimercaptosuccinic acid treatment of supernatants significantly increased the glutathione levels measured in the extracellular media. Utilization of MK571 and verapamil, multidrug resistance-associated protein 1 and Pgp inhibitors, decreased the rate of glutathione efflux from erythrocytes suggesting a role for these membrane transporters in the process. The results of the present study indicate that human erythrocytes efflux glutathione in reduced free form and in conjugated form or forms that can be recovered with dimercaptosuccinic acid when exposed to arsenite.


Assuntos
Arsenicais/farmacologia , Eritrócitos/efeitos dos fármacos , Glutationa/metabolismo , Compostos de Sulfidrila/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Arseniatos/antagonistas & inibidores , Arseniatos/farmacologia , Arsenitos/antagonistas & inibidores , Arsenitos/farmacologia , Transporte Biológico/efeitos dos fármacos , Biotransformação/efeitos dos fármacos , Quelantes/farmacologia , Meios de Cultivo Condicionados/metabolismo , Membrana Eritrocítica/efeitos dos fármacos , Membrana Eritrocítica/metabolismo , Eritrócitos/metabolismo , Glutationa/análogos & derivados , Humanos , Moduladores de Transporte de Membrana/farmacologia , Proteínas Associadas à Resistência a Múltiplos Medicamentos/antagonistas & inibidores , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Concentração Osmolar , Oxirredução , Compostos de Sódio/antagonistas & inibidores , Compostos de Sódio/farmacologia , Compostos de Sulfidrila/antagonistas & inibidores , Temperatura
8.
J Trace Elem Med Biol ; 26(1): 53-8, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22177801

RESUMO

OBJECTIVE: The objective of the present study was to investigate if arsenate V exposure results in glutathione efflux from human erythrocytes. PROCEDURE: The changes in intracellular and extracellular nonprotein sulfhydryl and glutathione levels were determined in arsenate (V) exposed erythrocytes. Presence of any cellular membrane damage was assessed by lactate dehydrogenase activity measurement in the supernatant. RESULTS: When erythrocytes were exposed to 10 mM of arsenate (V) for 4 h, the intracellular NPSH level decreased to 0.28±0025 µmol/ml erythrocyte. In contrast, extracellular nonprotein thiol level was increased to 0.180±0.010 µmol/ml erythrocyte in 4 h. Extracellular glutathione levels reached to 0.028±0.001, 0.052±0.002, and 0.054±0.004 µmol/ml erythrocyte with 1, 5, and 10 mM of arsenate (V), respectively. Utilization of MK571 a multi drug resistance-associated protein 1 inhibitor decreased the rate of glutathione efflux from erythrocytes suggesting a role for this membrane transporter in the process. CONCLUSION: The results of the present study indicate that erythrocytes efflux glutathione when exposed to arsenate (V).


Assuntos
Arseniatos/toxicidade , Eritrócitos/metabolismo , Glutationa/metabolismo , Contagem de Eritrócitos , Humanos , Hidroliases/metabolismo , Oxirredução
9.
Free Radic Res ; 40(5): 507-12, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16551577

RESUMO

The objective of this study was to investigate if erythrocytes play a role in the maintenance of redox homeostasis of the plasma. Thus, we studied L-cysteine efflux and influx in vitro in human erythrocytes. In the present study, we exposed the erythrocytes to different concentrations of L-cysteine and then measured the intracellular free -SH concentrations. Erythrocytes treated in the same manner were later utilized for the cysteine efflux studies. The effect of temperature on the influx and the efflux processes were also evaluated. Change in the free -SH content of the buffer was evaluated as a measure for the presence of an efflux process. The effects of free -SH depletion on L-cysteine transport is also investigated. We also determined the rate of L-cysteine efflux in the presence and absence of buthionine sulfoximine (BSO) in erythrocytes that are pretreated with 1-chloro-2,4-dinitro benzene, a glutathione (GSH) depletory. Our L-cysteine influx studies demonstrated that erythrocytes can respond to increases in L-cysteine concentration in the extracellular media and influx L-cysteine in a concentration-dependent manner. Free -SH concentrations in erythrocytes treated with 1 mM L-cysteine reached to 1.64 +/- 0.06 mM in 1 h whereas this concentration reached to 4.30 +/- 0.01 mM in 10 mM L-cysteine treated erythrocytes. The L-cysteine efflux is also determined to be time-and concentration-dependent. Erythrocytes that are pretreated with higher L-cysteine concentrations displayed a higher efflux process. Outside concentration of free -SH in 1 mM L-cysteine pretreated erythrocytes reached to 0.200 +/- 0.005 mM in 1 h whereas this concentration reached to 1.014 +/- 0.002 with 10 mM L-cysteine pretreated erythrocytes. Our results also indicate that the rate of inward and outward transport of L-cysteine is affected by the oxidative status of the erythrocytes. When GSH is depleted and GSH synthesis is blocked, the L-cysteine uptake and the efflux processes are significantly decreased. Depending on our results, it could be concluded that erythrocytes play a role in the regulation of the plasma redox status and intracellular level of GSH determines the rate of the L-cysteine efflux.


Assuntos
Cisteína/metabolismo , Eritrócitos/metabolismo , Glutationa/metabolismo , Oxirredução , Plasma/metabolismo , Homeostase/fisiologia , Humanos , Compostos de Sulfidrila/análise
10.
Med Hypotheses ; 64(2): 328-32, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15607566

RESUMO

There have been several attempts to prevent tumor formation and growth. However, none of the developed methods gives a completely satisfying result for the treatment of tumor masses. The most often used therapies against tumor cells are radiotherapy and chemotherapy. However, utilization of these methods to treat cancer generally result in generation of undesired side effects. In recent years, the antisense oligonucleotide technology has been employed, with success to an extent, in prevention of tumor growth. However, this method has its limitations. One of the most important limitation is that all of the crucial genes that play certain roles and are specifically expressed in tumor cells have not yet been identified. Therefore, only a few numbers of genes that are shown to play a role in tumor cells are targeted by the antisense oligonucleotide method. The aim of the present study is to propose a hypotheses and outline the involved procedure which could be used to generate oligonucleotides that are antisense to genes or mRNAs that display certain specific functions in tumor cells but are yet to be identified. The proposed hypotheses involves first, a careful isolation of differentially expressed mRNAs by using the tumor and the corresponding normal cells. These mRNAs should represent the genes that operate in tumor cells but not in the corresponding normal cells. Following the isolation of the differentially expressed mRNAs, they will be reverse transcribed and the desired amounts of cDNA copies will be obtained. The cDNA copies will then be used differentially as a source for oligonucleotides that are antisense to genes or mRNAs. To obtain the desired length oligonucleotides that will be used as antisense oligonucleotides the cDNA copies will be subjected to Maxam-Gilbert fragmentation and/or controlled enodonuclease digestion. These two mentioned procedures could be optimized and used together or separately to obtain the desired length oligonucleotides that will be used against tumor cells.


Assuntos
Inibidores do Crescimento/uso terapêutico , Neoplasias/prevenção & controle , Neoplasias/terapia , Oligonucleotídeos Antissenso/uso terapêutico , Oncogenes/genética , RNA Mensageiro/isolamento & purificação , Engenharia Genética/métodos , Terapia Genética/métodos , Humanos , Neoplasias/fisiopatologia
11.
Med Hypotheses ; 63(1): 80-2, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15193353

RESUMO

There have been several attempts to prevent the tumor growth and the resulting death. However, almost none of the developed methods designed to inhibit tumor growth gives a satisfactorily result without deleterious side effects. Some of the existing methods employed on prevention of tumor growth and invasion target the metabolic differences between normal and tumor cells. The most pronounced metabolic differences between normal and tumor cells appear to be in the energy generating pathways. The energy generating pathways in normal cells are inter-regulated and the most developed pathway controls the activity of the least developed pathway. Cancer cells do not respond to these regulations and as a result energy generating pathways start to operate independently. Among the energy generating pathways, the least developed or the most primitive pathway is the non-phosphorylating glycolysis. The increased activity of this pathway has been suggested to provide the cells with sufficient mitotic activity. It has been suggested that in non-phosphorylating glycolysis, glucose is broken down to lactate in a manner that requires glutathione. Here, I hypothesize that manipulation of intracellular glutathione concentrations as protecting the cells form oxidative stress may efficiently inhibit tumor growth. Glutathione is a soluble antioxidant and its concentration is high in prenatal tissue and in cancer cells. Though its primary function seems to combat against oxidant injury and toxic xenobiotics, glutathione is implicated in many other different cellular processes including cell proliferation and DNA and RNA synthesis. Another function of glutathione relevant to the subject is its involvement in detoxification of methylglyoxal, a compound that is generated at high concentrations in rapidly proliferating cells possessing an inhibitory activity on cell proliferation. Therefore, inhibition of intracellular glutathione concentration may negatively impact the tumor cell growth by at least three ways. The first is through inhibition of non-phosphorylating glycolysis that provides mitotic energy for cells. The second is through the inhibition of methylglyoxal metabolism and the third is through the redox regulation of DNA and RNA synthesis.


Assuntos
Acetilcisteína/metabolismo , Antineoplásicos/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Glicólise/efeitos dos fármacos , Neoplasias/metabolismo , Transdução de Sinais/efeitos dos fármacos , Animais , Humanos
12.
Toxicon ; 43(6): 619-32, 2004 May.
Artigo em Inglês | MEDLINE | ID: mdl-15109883

RESUMO

Nicotine is a naturally occurring alkaloid found in many plants. The principal sources of nicotine exposure is through the use of tobacco, nicotine containing gum and nicotine replacement therapies. Nicotine is an amine composed of pyridine and pyrrolidine rings. It has been shown that nicotine crosses biological membranes and the blood brain barrier easily. The absorbed nicotine is extensively metabolized in the liver to form a wide variety of metabolites including nicotine N'-oxide and cotinine N'-oxide. These are the products of mixed function oxidase system. Nicotine is also converted to some biologically important compounds during harvesting. Among these are the nitrosamines specific to tobacco. Nicotine has been shown to affect a wide variety of biological functions ranging from gene expression, regulation of hormone secretion and enzyme activities. The objective of this study was to overview the biological effects and metabolism of nicotine.


Assuntos
Nicotina/toxicidade , Apoptose/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Humanos , Mutagênicos/farmacocinética , Mutagênicos/toxicidade , Nicotina/farmacocinética
13.
Toxicol Mech Methods ; 14(4): 241-5, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-20021137

RESUMO

In previous studies, the transport of dinitrophenyl-glutathione from erythrocytes has been extensively investigated. However, the effect of treatment of erythrocytes with such xenobiotics on free-SH status of cells has not been well documented. Also, the effects of N-acetyl-L-cysteine or other-SH containing compounds on glutathione conjugate transport have not been investigated. The objectives of the present study were to investigate how the presence N-acetyl-L-cysteine and L-cysteine affect the free-SH status of 1-chloro-2,4-dinitrobenzene treated erythrocytes and how N-acetyl-L-cysteine or L-cysteine affects the rate of dinitrophenyl-glutathione conjugate transport form erythrocytes. Our results indicated that L-cysteine is more efficient than N-acetyl-L-cysteine in increasing the free-SH content of erythrocytes in the presence of 1-chloro-2,4-dinitrobenzene. At the end of 20 min of exposure, free-SH levels remained at 5.3 mumol/ml erythrocyte in the presence of L-cysteine. However, in the presence of N-acetyl-L-cysteine the free-SH level was 2 mumol/ml erythrocyte. In the absence of 1-chloro-2,4-dinitrobenze, L-cysteine uptake by erythrocytes was not efficient compared to N-acetyl-L-cysteine. The free-SH concentrations in the presence of N-acetyl-L-cysteine and L-cysteine, in this case were, 9 +/- 1 and 1.5 +/- 0.1 mumol/ml erythrocytes respectively. These results clearly suggest that 1-chloro-2,4-dinitrobenzene stimulates the L-cysteine uptake in eryhtrocytes by a mechanism not described before. Our results also indicated that 1-chloro-2,4-dinitrobenzene induced L-cysteine uptake is a Na(+) and ATP dependent process. Replacement of NaCl with LiCl decreased the L-cysteine uptake by about 5-fold and in the presence of NaF decrease in L-cysteine uptake was about 2 fold. Our results conclude the presence of an in vitro L-cysteine uptake mechanism in erythrocytes stimulated by 1-chloro-2,4-dinitrobenzene.

14.
Toxicol Mech Methods ; 14(4): 253-6, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-20021139

RESUMO

Nicotine and smokeless tobacco extract have been shown to induce oxidative stress in different experimental systems. However, the effect of nicotine and smokeless tobacco extract containing equal amounts of nicotine on 8-OH-dG formation has not been investigated. 8-OH-dG is a DNA adduct formed by free radical attack and is elevated in tumor cells. The objective of the present study was to evaluate the formation of 8-OH-dG following exposure to different concentrations of nicotine and smokeless tobacco extract containing equal amounts of nicotine. Exposure of Chinese Hamster Ovary cells to 5 and 10 mM of nicotine resulted in generation of 8-OH-dG. The observed 8-OH-dG levels at these concantrations of nicotine were 5.1 +/- 1.7 and 9.4 +/- 2.3 8-OH-dG/dG x 100.000, respectively. Smokeless tobacco extract containing 1 and 5 mM nicotine also induced generation of 8-OH-dG. The measured 8-OH-dG levels at these concentrations were 4.7 +/- 0.6 and 20.6 +/- 2.2 8-OH-dG/dG x 100.000 respectively. Exposure of cells to smokeless tobacco extract containing 10 mM nicotine resulted in cell death. Coaddition of superoxide dismutase and catalase along with nicotine reversed the 8-OH-dG generation. However, superoxide dismutase and catalase did not inhibit the 8-OH-dG generation in smokeless tobacco extract treated cells.

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