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1.
Artigo em Chinês | MEDLINE | ID: mdl-38403419

RESUMO

Objective: Explore the application of Delphi method and analytic hierarchy process to explore the construction of scientific, objective and comprehensive evaluation index system for healthy enterprise construction and promote the construction of healthy enterprises. Methods: In October 2022, through Delphi expert consultation and analytic hierarchy process, the indexes were screened and the weights of the indexes were determined, and the evaluation index system of healthy enterprises was established. Results: The positive coefficients of experts in the two rounds were all 100.00%, the authority coefficient of experts was 0.82, the coefficients of variation of the indexes in the two rounds were all less than 0.30. The coordination coefficients of experts in the first and second rounds were 0.64 and 0.77, respectively (P<0.001) . After two rounds of Delphi method expert consultation, a healthy enterprise evaluation index system including 4 first-level indexes, 14 second-level indexes, and 63 third-level indexes was constructed. Conclusion: The constructed health enterprise evaluation index system is highly scientific and reliable, covering the main factors of healthy enterprise construction, and providing a reliable and quantifiable basis and self-assessment basis for the establishment of healthy enterprises.


Assuntos
Processo de Hierarquia Analítica , Nível de Saúde , Técnica Delphi , China
2.
Artigo em Chinês | MEDLINE | ID: mdl-34624944

RESUMO

Objective: To study the correlation between occupational radiation exposure and chronic metabolic diseases. Methods: The status of chronic metabolic diseases of medical workers were compared in 5 hospitals in Hangzhou. As representatives of chronic metabolic diseases, diabetes and metabolic syndrome (MS) were compared in association with duration of radiation exposure. Results: Long-term ionizing radiation (IR) exposure was led to increased blood pressure, fasting blood glucose (FBG) , dyslipidemia, gallbladder disease, and MS. The years of radiation exposure was associated with lens opacity, gallstone and MS in men and gallbladder polyps in women. Radiation working more than 10 years is one of the independent risk factors for increased FBG and MS. Moreover, the risk of FBG increase in the group of radiation working more than 10 years was 3.052 times of that the non-exposed group, and the risk of MS occurrence was 4.132 times that of the non-exposed group. Conclusion: Long-term exposure to IR increases the risk of chronic metabolic diseases.


Assuntos
Catarata , Exposição Ocupacional , Traumatismos Ocupacionais , Exposição à Radiação , Lesões por Radiação , Feminino , Humanos , Masculino , Exposição à Radiação/efeitos adversos
3.
Artigo em Chinês | MEDLINE | ID: mdl-32629570

RESUMO

Objective: To investigate the detection of suspected occupational diseases in the occupational health examination population in Hangzhou, and to establish a two-level logistic model of influencing factors. Methods: In October 2018, the information of physical examinees was collected through the 2015-2017 occupational health examination and reexamination database of Hangzhou Hospital for the Prevention and Treatment of Occupational Disease. MlwiN 2.02 software was used to establish a 2-level logistic model of suspected occupational diseases, with the occupational hazard factors as the level 2 unit and the employees as the level 1 unit. χ(2) test was used to compare the detection rates of suspected occupational diseases with different characteristics. The trend of detection rates of suspected occupational diseases with age and working age were tested by Cochran-Armitage trend test. Results: The morbidity rate of suspected occupational diseases in 2965 workers was 59.6% (1767/2965) , and the rates caused by different occupational hazardous factors were significantly difference (χ(2)=1615.27, P<0.01) , that caused by noises was the highest (98.0%, 1206/1231) , and the next was the dust (87.5%, 70/80) . The rate in male was 61.5% (1532/2492) , and that in female was 49.7% (235/473) , they were significantly difference (χ(2)=22.96, P<0.01) . The rates of suspected occupational diseases increased with the ages (Z=8.77, P<0.01) and working years (Z=3.62, P<0.01) . The multivariate analysis by 2-level logistic model indicated that gender, age and working year were all no significant, instead the level 2 unit random effect was significant (χ(2)=4.77, P<0.05) . Conclusion: Suspected occupational diseases will occur in clusters in occupational hazardous factors. The influence of occupational hazardous factors on suspected occupational diseases was more than that of personal characteristics.


Assuntos
Doenças Profissionais/epidemiologia , Poeira , Feminino , Hospitais , Humanos , Recém-Nascido , Modelos Logísticos , Masculino , Doenças Profissionais/diagnóstico
4.
Artigo em Chinês | MEDLINE | ID: mdl-30248751

RESUMO

Objective: To establish a method for determination the S-phenylmercapturic acid in urine by dispersive solid-phase extraction using Humic Acid/Fe(3)O(4) magnetic nanocomposite as adsorbent. Methods: The 5 ml of urine samples were adjusted to pH 1.0 and extracted by Fe3O4@HA. Then the analytes were separated on EC-C(18) capillary column and detected by HPLC-VWD. The S-phenylmercapturic acid was characterized by the retention time and quantified by peak area and external standard method. Results: The standard curves of SPMA showed significant linearity between 0.04~1.00 mg/L (r=0.999 7) . The average recovery was 94.2%~102.4%. The intra-day and inter-day precisions (RSD) were 2.9~6.7% (n=6) and 3.1~7.5% (n=6) respectively. The detect limit of SPMA was 0.012 g/L (S/N=3) . Conclusion: This method is simple, rapid, sensitive and accurate. It is applicable for determination of SPMA in the urine of works who were exposed to benzene.


Assuntos
Acetilcisteína/análogos & derivados , Substâncias Húmicas , Nanocompostos , Exposição Ocupacional/análise , Extração em Fase Sólida , Acetilcisteína/urina , Biomarcadores/urina , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Sensibilidade e Especificidade
5.
Eur Rev Med Pharmacol Sci ; 22(8): 2207-2211, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29762820

RESUMO

OBJECTIVE: This study explores the possible relation between cervical infections with Ureaplasma urealyticum (UU) and Mycoplasma hominis (MH) and the occurrence of recurrent spontaneous abortion (RSA). PATIENTS AND METHODS: 132 patients with RSA (observation group) and 96 normal pregnancy volunteers undergoing planned abortions (control group) were selected successively and enrolled in the investigation. Cervical secretion samples were obtained for each subject. Bacterial cultures were started to detect UU, MH and other bacterial infections, and fluorescence quantitative PCR was used to detect gene copy number in chorion and decidual tissues. Additionally, ELISA (enzyme-linked immunosorbent assay) was used to detect anticardiolipin antibody (ACA) to rate positivity of Immunoglobulin M (IgM) and IgG in secretions, and Western blot was applied to quantify the expression levels of Interleukin (IL)-6, tumor necrosis factor-α (TNF-α), prostacyclin (PGI2) and bax/bcl-2. RESULTS: Our results showed the UU, MH, and overall bacterial infection rate of chorionic and decidual tissues, and the gene copy number of UU, MH were higher in the observation group than those in the control group (p<0.05). Moreover, the ACA-IgM and IgG positive rates in secretions of the observation group were significantly higher than those in the control group (p<0.05). Finally, the expression levels of IL-6, TNF-α, PGI2, and bax/bcl-2 were higher than those in the control group as well (p<0.05). CONCLUSIONS: Our results support the notion that RSA might be associated with UU and MH infection, could influence the occurrence of other bacterial infections and could stimulate ACA expression, inflammatory response, thrombogenesis, and factors associated with cell apoptosis, increasing the risk for an abortion during pregnancy.


Assuntos
Aborto Habitual/etiologia , Infecções por Mycoplasma/complicações , Infecções por Ureaplasma/complicações , Adulto , Anticorpos Anticardiolipina/sangue , Feminino , Humanos , Imunoglobulina G/sangue , Imunoglobulina M/sangue , Gravidez
6.
Braz J Med Biol Res ; 51(3): e6426, 2018 Jan 11.
Artigo em Inglês | MEDLINE | ID: mdl-29340520

RESUMO

Occupational noise-induced hearing loss (ONIHL) is a prevalent occupational disorder that impairs auditory function in workers exposed to prolonged noise. However, serum microRNA expression in ONIHL subjects has not yet been studied. We aimed to compare the serum microRNA expression profiles in male workers of ONIHL subjects and controls. MicroRNA microarray analysis revealed that four serum microRNAs were differentially expressed between controls (n=3) and ONIHL subjects (n=3). Among these microRNAs, three were upregulated (hsa-miR-3162-5p, hsa-miR-4484, hsa-miR-1229-5p) and one was downregulated (hsa-miR-4652-3p) in the ONIHL group (fold change >1.5 and Pbon value <0.05). Real time quantitative PCR was conducted for validation of the microRNA expression. Significantly increased serum levels of miR-1229-5p were found in ONIHL subjects compared to controls (n=10 for each group; P<0.05). A total of 659 (27.0%) genes were predicted as the target genes of miR-1229-5p. These genes were involved in various pathways, such as mitogen-activated protein kinase (MAPK) signaling pathway. Overexpression of miR-1229-5p dramatically inhibited the luciferase activity of 3' UTR segment of MAPK1 (P<0.01). Compared to the negative control, HEK293T cells expressing miR-1229-5p mimics showed a significant decline in mRNA levels of MAPK1 (P<0.05). This preliminary study indicated that serum miR-1229-5p was significantly elevated in ONIHL subjects. Increased miR-1229-5p may participate in the pathogenesis of ONIHL through repressing MAPK1 signaling.


Assuntos
Perda Auditiva Provocada por Ruído/sangue , MicroRNAs/sangue , Proteína Quinase 1 Ativada por Mitógeno/análise , Doenças Profissionais/sangue , Exposição Ocupacional/efeitos adversos , Adulto , Biomarcadores/sangue , Estudos de Casos e Controles , Regulação da Expressão Gênica , Ontologia Genética , Perda Auditiva Provocada por Ruído/genética , Humanos , Masculino , MicroRNAs/genética , Pessoa de Meia-Idade , Doenças Profissionais/genética , Reação em Cadeia da Polimerase em Tempo Real
7.
Artigo em Chinês | MEDLINE | ID: mdl-27514260

RESUMO

OBJECTIVE: To investigate the current status of hearing loss and the use of earplugs in workers exposed to noise who have been provided earplugs in a city, as well as major influencing factors for the use of earplugs. METHODS: Cluster random sampling was used to conduct a questionnaire survey in workers exposed to noise who had been provided earplugs in 15 enterprises with noise exposure in a city from June to December, 2014. RESULTS: In the workers exposed to noise who had been provided earplugs, the rate of high-frequency anomaly in both ears was 57.8%, and the workers who kept wearing earplugs only accounted for 55.4%. The results of binary logistic regression analysis showed that the protective factors for the use of earplugs included workers' own feeling of hearing condition (OR=1.704), comfort of earplugs (OR= 1.892), enterprise's inspection of the use of earplugs (OR=1.461), workers' knowledge of the function and usage of earplugs (OR=1.581), workers' understanding of the necessity of earplugs (OR=4.482), workers' initiative to search for related data (OR=4.029), the use of earplugs by colleagues (OR=5.071), and reminders from family members or friends (OR=2.678) (all P<0.05). CONCLUSION: The workers exposed to noise in this city have a high rate of abnormal hearing, and only half of the workers keep wearing earplugs during work. The use of earplugs is related to the factors including workers' own feeling of hearing condition, comfort of earplugs, workers' knowledge of protection, the enterprise' s management of hearing protection, and environmental support.


Assuntos
Dispositivos de Proteção das Orelhas , Ruído Ocupacional , Audição , Perda Auditiva Provocada por Ruído , Testes Auditivos , Humanos , Inquéritos e Questionários
8.
In Vitro Cell Dev Biol Anim ; 35(9): 493-500, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10548430

RESUMO

Organophosphate (OP) anticholinesterases were found to modulate metabolic activities of human neuroblastoma cells and hepatocytes, which was detectable by the Cytosensor microphysiometer. The nerve gas ethyl-S-2-diisopropylaminoethyl methylphosphorothiolate (VX), at 10 microM, produced significant reduction in cell metabolism within 2 min, as measured by changes in the acidification rate of the medium. The reduction was dose- and time-dependent and irreversible after 4 h of exposure. Two alkaline degradation products of VX produced no cytotoxicity. Exposure for 24 h to 3 microM VX caused 36% and 94% irreversible loss of metabolism in hepatocytes and neuroblastoma cells, respectively. The insecticides parathion and chlorpyrifos stimulated hepatocyte metabolism but inhibited neuroblastoma cells. Their oxons were more active. Exposure of neuroblastoma cells for 4 h to VX, parathion, paraoxon, diisopropylfluorophosphate or chlorpyrifos gave an LC50 of 65, 775, 640, 340, or 672 microM, respectively, whereas 24 h gave an LC50 of 0.7, 3.7, 2.5, 29, and 31 microM, respectively. Preincubation of hepatocytes with phenobarbital enhanced their response to parathion and VX due to metabolic bioactivation. Atropine partially blocked the effects of VX and paraoxon on both cell types, which suggests the involvement of a muscarinic receptor as the target for cytotoxicity. There was no correlation between OP in vivo neurotoxicity and in vitro cytotoxicity. It is suggested that the former results from their cholinesterase inhibition, while the latter results from action on different targets and requires much higher concentrations.


Assuntos
Substâncias para a Guerra Química/toxicidade , Inibidores da Colinesterase/toxicidade , Compostos Organotiofosforados/toxicidade , Acetilcolinesterase/metabolismo , Atropina/farmacologia , Biotransformação , Substâncias para a Guerra Química/metabolismo , Clorpirifos , Inibidores da Colinesterase/metabolismo , Humanos , Inseticidas/metabolismo , Inseticidas/toxicidade , Compostos Organotiofosforados/metabolismo , Fenobarbital/farmacologia , Receptores Muscarínicos/metabolismo
9.
Toxicon ; 36(2): 269-81, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9620575

RESUMO

The sea nettle jellyfish toxin (SNTX), which contains several polypeptides, was highly toxic to human hepatocytes. The Cytosensor microphysiometer was used continuously to monitor cell media acidification rate as an index of cellular metabolic activity. Cells exposed to > 1 microg SNTX protein/ml media exhibited a transient increase in metabolic activity, followed by a sharp decrease and cell death within minutes. The kinetics of the transient increase and subsequent decline increased with higher concentrations of SNTX. The biphasic and time-dependent response of hepatocytes to SNTX suggests that more than one mechanism may be involved in the toxicity of its different polypeptides. SNTX-induced cytotoxicity of hepatocytes was reduced by the presence of high titer antibodies against a heterologous jellyfish. Phenobarbital-induced cells became more vulnerable to SNTX, suggesting that some toxin component(s) require(s) bioactivation. Short-term exposure (1-2 h) to 10 microg/ml of the calcium ionophore calcimycin, or the non-selective monovalent cation ionophore gramicidin, had no effect on metabolic activity. However, 165 microg/ml gramicidin or 53 microg/ml calcimycin produced slight transient activation followed by steady decline in metabolic activity, while 20 h exposure to either ionophore produced total cell death. Exposure to even a 10-fold lower concentration of either ionophore killed 88% and 75%, respectively. This contrasts with the toxicity of SNTX which is detectable in minutes with as little as 3 microg/ml. Since pre-exposure to the organophosphate anticholinesterases VX and paraoxon, or the chemotherapeutic alkylating agents cyclophosphamide and mechlorethamine reduced the cytotoxic effects of SNTX, it suggests that phosphorylation or alkylation of cell protein(s) interferes with SNTX toxicity.


Assuntos
Alquilantes/farmacologia , Venenos de Cnidários/toxicidade , Fígado/efeitos dos fármacos , Cifozoários , Animais , Antibacterianos/farmacologia , Calcimicina/farmacologia , Morte Celular/efeitos dos fármacos , Células Cultivadas , Venenos de Cnidários/antagonistas & inibidores , Venenos de Cnidários/isolamento & purificação , Interações Medicamentosas , Gramicidina/farmacologia , Humanos , Hipnóticos e Sedativos/farmacologia , Ionóforos/farmacologia , Fígado/metabolismo , Fenobarbital/farmacologia , Fosforilação
10.
Toxicol In Vitro ; 11(3): 285-93, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-20654314

RESUMO

The Cytosensor() microphysiometer was used to continuously monitor perturbations in metabolic rates of the human liver cell line ATCC-CCL-13 when exposed to each of 10 drugs. The effects of exposure to one concentration for 24 hr or to sequential increasing concentrations for 4 hr, and recovery after drug removal, were compared. Paracetamol (acetaminophen) and ethanol were used to establish the assay protocols and determine reversibility of drug effect. All drugs produced concentration-and time-dependent reduction in acidification rate following 24 hr exposure, which may be due to decreased number of viable cells and/or lowered metabolic rates of the live cells. The degree of irreversible inhibition of acidification rate was used as an index of cell death and the IC(50) values for the 10 drugs were comparable to those produced in the same cell line by a fluorescence assay using Calcein AM stain (r = 0.991), that fluoresces only in live cells, as well as the [(3)H]thymidine uptake assay (r = 0.976). There was also excellent correlation (r = 0.958) between IC(50) values of 24 hr exposure obtained from the Cytosensor with the 10 drugs and their published human lethal blood concentrations. An advantage of this new methodology over other in vitro assays is that it allows the determination of time points at which reversible change becomes irreversible.

11.
Fundam Appl Toxicol ; 16(4): 810-20, 1991 May.
Artigo em Inglês | MEDLINE | ID: mdl-1909249

RESUMO

An optical sensor for anticholinesterases (AntiChEs) was constructed by immobilizing fluorescein isothiocyanate (FITC)-tagged eel electric organ acetylcholinesterase (AChE) on quartz fibers and monitoring enzyme activity. The pH-dependent fluorescent signal generated by FITC-AChE, present in the evanescent zone on the fiber surface, was quenched by the protons produced during acetylcholine (ACh) hydrolysis. Analysis of the fluorescence response showed Michaelis-Menten kinetics with a Kapp value of 420 microM for ACh hydrolysis. The reversible inhibitor edrophonium (0.1 mM) inhibited AChE and consequently reduced fluorescence quenching. The biosensor response immediately recovered upon its removal. The carbamate neostigmine (0.1 mM) also inhibited the biosensor response but recovery was much slower. In the presence of ACh, the organophosphate (OP) diisopropylfluorophosphate (DFP) at 0.1 mM did not interfere with the ACh-dependent fluorescent signal quenching, but preexposure of the biosensor to DFP in absence of ACh inhibited totally and irreversibly the biosensor response. However, the DFP-treated AChE biosensor recovered fully after a 10-min perfusion with pralidoxime (2-PAM). Echothiophate, a quaternary ammonium OP, inhibited the ACh-induced fluorescence quenching in the presence of ACh and the phosphorylated biosensor was reactivated with 2-PAM. These effects reflected the mechanism of action of the inhibitors with AChE and the inhibition constants obtained were comparable to those from colorimetric methods. The biosensor detected concentrations of the carbamate insecticides bendiocarb and methomyl and the OPs echothiophate and paraoxon in the nanomolar to micromolar range. Malathion, parathion, and dicrotophos were not detected even at millimolar concentrations; however, longer exposure or prior modification of these compounds (i.e., to malaoxon, paraoxon) may increase the biosensor detection limits. This AChE biosensor is fast, sensitive, reusable, and relatively easy to operate. Since the instrument is portable and can be self-contained, it shows potential adaptability to field use.


Assuntos
Acetilcolinesterase , Técnicas Biossensoriais , Inibidores da Colinesterase/análise , Animais , Enguias , Enzimas Imobilizadas , Tecnologia de Fibra Óptica , Fluoresceína-5-Isotiocianato , Fluoresceínas , Concentração de Íons de Hidrogênio , Cinética , Neostigmina/farmacologia , Fibras Ópticas , Tiocianatos
12.
Mol Cell Biochem ; 103(2): 97-111, 1991 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-1649382

RESUMO

In reconstituted rabbit skeletal muscle (Ca2+ + Mg2+)-ATPase proteoliposomes, Ca(2+)-uptake is decreased by more than 90% with T2 cleavage (Arg-198). However, no difference in the ATP dependence of hydrolysis activity is seen between SR and trypsin-treated SR. A large decrease in E-P formation and hydrolysis activity of the enzyme appear only at T3 cleavage, which represents the cleavage of A1 fragment to A1a + A1b forms. The disappearance of hydrolysis activity due to digestion is prior to the disappearance of E-P formation. No significant difference is found in the passive Ca2+ efflux between control SR and tryptically digested SR in the absence of Mg2+ + ruthenium red or in the presence of ATP. However, the passive Ca2+ efflux rate for tryptically digested SR is much larger than control SR in the presence of Mg2+ + ruthenium red. These results show that the Ca2+ channel cannot be closed after trypsin digestion of SR membranes by the presence of the Ca2+ channel inhibitors, Mg2+ and ruthenium red. In the reconstituted proteoliposomes, the Ca2+ efflux rates are the same regardless of digestion (T2); also, efflux is not affected by the presence or absence of Mg2+ + ruthenium red. These results indicate that T2 cleavage causes 'uncoupling' of the 'Ca(2+)-pump' from ATP hydrolytic activity. A theoretical model is developed in order to fit the extent of tryptic digestion of the A fragment of the (Ca2+ + Mg2+)-ATPase polypeptide with the loss of Ca(2+)-transport. Fits of the theoretical equations to the data are consistent with that Ca(2+)-transport system appears to require a dimer of the polypeptide (Ca2+ + Mg2+)-ATPase.


Assuntos
Trifosfato de Adenosina/metabolismo , ATPase de Ca(2+) e Mg(2+)/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Cálcio/metabolismo , Retículo Sarcoplasmático/enzimologia , Animais , Transporte Biológico Ativo , Canais de Cálcio/metabolismo , Colorimetria , Eletroforese em Gel de Poliacrilamida , Lipossomos/metabolismo , Matemática , Modelos Biológicos , Coelhos , Retículo Sarcoplasmático/metabolismo , Tripsina/metabolismo
13.
Mol Cell Biochem ; 99(2): 67-74, 1990 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-2149585

RESUMO

Europium luminescence from europium bound to sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPase indicates that there are two high affinity calcium binding sites. Furthermore, the two calcium ions at the binding sites are highly coordinated by the protein as the number of H2O molecules surrounding the Ca2+ ions are 3 and 0.5. In the presence of ATP, calcium ions are occluded even further down to 2 and zero H2O molecules, respectively. The Ca2+ - Ca2+ intersite distance is estimated to be 8-9 A and the average distance from the Ca2+ sites to CrATP is about 18 A. Digestion of the (Ca2+ + Mg2+)-ATPase at the T2 site (Arg 198) causes uncoupling of Ca2(+)-transport from ATPase activity while calcium occlusion due to E1-P formation remains unchanged. Further tryptic digestion beyond T2 and in the presence of ATP diminishes Ca2+ occlusion to zero while 50% of the ATPase hydrolytic activity remains. Tryptic digestion beyond T2 and in the absence of ATP diminishes ATPase hydrolytic activity to 50% of normal while Ca2+ occlusion remains intact. These data are consistent with a mechanism in which the functional enzyme must be in the dimeric form for occlusion and calcium uptake to occur, but each monomer can hydrolyze ATP.


Assuntos
ATPase de Ca(2+) e Mg(2+)/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Cálcio/metabolismo , Retículo Sarcoplasmático/metabolismo , Trifosfato de Adenosina/metabolismo , Sítios de Ligação , Transporte Biológico Ativo , Európio , Fluorescência , Medições Luminescentes , Conformação Proteica , Tripsina/metabolismo
15.
Life Sci ; 47(7): 655-67, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2402189

RESUMO

Uptake of the catecholamines (CA), dopamine (DA) and norepinephrine (NE) into synaptosomes prepared from rat and bovine brains was potentiated by ATP (from 0.1 to 5.0 mM) in a dose-dependent manner. Other nucleotides, particularly the nonhydrolyzable ATP analogs beta,gamma-imidoadenosine-5'-triphosphate (AMP-PNP) and beta,gamma-methyladenosine-5'-triphosphate (AMP-PCP) also potentiated [3H]DA and [3H]NE uptake. Several endogenous 5'-nucleotide triphosphates (e.g. GTP, UTP and CTP) potentiated [3H]CA uptake, but were less effective than ATP. Among the ATP metabolites, only ADP potentiated uptake whereas AMP and adenosine did not. [3H]Dopamine uptake measured in Krebs bicarbonate buffer had a Km of 2.1 microM and a Vmax of 163.9 pmol/mg prot./min. In presence of ATP, [3H]DA uptake had much higher affinity (Km = 0.56 microM) and larger capacity (Vmax = 333 pmol/mg prot./min) than uptake in absence of added ATP. Furthermore, [3H]DA uptake in presence of ATP had faster rate of uptake, and was independent of temperature while in absence of added ATP it was temperature-dependent. This ATP-dependent [3H]DA uptake was retained by synaptosomal ghosts that were obtained after lysing the striatal synaptosomes and removing their contents of synaptic vesicles and mitochondria. It is proposed that, in addition to the carrier-mediated (neuronal) uptake of CA, there is neuronal uptake that is regulated by ATP and inhibited by cocaine, which may be more relevant for terminating the synaptic action of CA because of its faster rate of uptake and larger capacity.


Assuntos
Trifosfato de Adenosina/fisiologia , Dopamina/metabolismo , Neurônios/metabolismo , Norepinefrina/metabolismo , Sinaptossomos/metabolismo , Animais , Aminas Biogênicas/metabolismo , Bovinos , Técnicas In Vitro , Cinética , Masculino , Nucleotídeos/fisiologia , Ratos , Ratos Endogâmicos , Receptores Purinérgicos/fisiologia , Serotonina/metabolismo , Temperatura
16.
Membr Biochem ; 8(4): 207-20, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2562128

RESUMO

Dopamine transporters of bovine and rat striata were identified by their specific [3H]cocaine binding and cocaine-sensitive [3H]dopamine [( 3H]DA) uptake. Both binding and uptake functions of bovine striatal transporters were potentiated by lectins. Concanavalin A (Con A) increased the velocity but did not change the affinity of the transporter for DA; however, it increased its affinity for cocaine without changing the number of binding sites. This suggests that the DA transporter is a glycoprotein and that Con A action on it produces conformational changes. Inorganic and organic mercury reagents inhibited both [3H]DA uptake and [3H]cocaine binding, though they were all more potent inhibitors of the former. n-Ethylmaleimide inhibited [3H]DA uptake totally but [3H]cocaine binding only partially. Also, n-pyrene maleimide had differential effects on uptake and binding, inhibiting uptake and potentiating binding. [3H]DA uptake was not affected by mercaptoethanol up to 100 mM, whereas [3H]cocaine binding was inhibited by concentrations above 10 mM. On the other hand, both uptake and binding were fairly sensitive to dimercaprol (less than 1 mM). The effects of all these sulfhydryl reagents suggest that the DA transporter has one or more thiol group(s) important for both binding and uptake activities. The Ellman reagent and dithiopyridine were effective inhibitors of uptake and binding only at fairly high concentration (greater than 10 mM). Loss of activity after treatment with the dithio reagents may be a result of reduction of a disulfide bond, which may affect the transporter conformation.


Assuntos
Proteínas de Transporte , Corpo Estriado/metabolismo , Glicoproteínas/metabolismo , Receptores de Droga/metabolismo , Compostos de Sulfidrila/metabolismo , 4-Cloromercuriobenzenossulfonato/farmacologia , Animais , Transporte Biológico/efeitos dos fármacos , Bovinos , Cocaína/metabolismo , Cocaína/farmacologia , Concanavalina A/farmacologia , Corpo Estriado/efeitos dos fármacos , Dopamina/metabolismo , Cinética , Lectinas/farmacologia , Masculino , Maleimidas/farmacologia , Cloreto de Mercúrio/farmacologia , Ratos , Ratos Endogâmicos , Reagentes de Sulfidrila/farmacologia , Sinaptossomos/metabolismo
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