Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 36
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Antiviral Res ; 158: 127-134, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-30059721

RESUMO

The European Virus Archive (EVA) was created in 2008 with funding from the FP7-EU Infrastructure Programme, in response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry. Within three years, it developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. In 2014, the H2020 Research and Innovation Framework Programme (INFRAS projects) provided support for the transformation of the EVA from a European to a global organization (EVAg). The EVAg now operates as a non-profit consortium, with 26 partners and 20 associated partners from 21 EU and non-EU countries. In this paper, we outline the structure, management and goals of the EVAg, to bring to the attention of researchers the wealth of products it can provide and to illustrate how end-users can gain access to these resources. Organisations or individuals who would like to be considered as contributors are invited to contact the EVAg coordinator, Jean-Louis Romette, at jean-louis.romette@univmed.fr.


Assuntos
Arquivos , Bancos de Espécimes Biológicos/organização & administração , Recursos em Saúde/organização & administração , Vírus , Pesquisa Biomédica , Europa (Continente) , Humanos , Disseminação de Informação , Organizações de Serviços Gerenciais , Coronavírus da Síndrome Respiratória do Oriente Médio , Saúde Pública , Controle de Qualidade , Segurança/normas , Virologia/métodos , Febre Amarela/epidemiologia , Febre Amarela/virologia , Infecção por Zika virus/epidemiologia , Infecção por Zika virus/virologia
2.
Antiviral Res ; 95(2): 167-71, 2012 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-22626637

RESUMO

The European Virus Archive (EVA) was conceived as a direct response to the need for a coordinated and readily accessible collection of viruses that could be made available to academia, public health organisations and industry, initially within Europe, but ultimately throughout the world. Although scientists worldwide have accumulated virus collections since the early twentieth century, the quality of the collections and the viruses collected may vary according to the personal interests and agenda of the scientists. Moreover, when laboratories are re-organised or closed, collections are no longer maintained and gradually cease to exist. The tragedy of 9/11 and other disruptive activities have also meant that some previously available biological reagents are no longer openly exchanged between countries. In 2008, funding under the FP7-EU infrastructure programme enabled the initiation of the EVA. Within three years, it has developed from a consortium of nine European laboratories to encompass associated partners in Africa, Russia, China, Turkey, Germany and Italy. There is every reason to believe that EVA will continue to expand and ultimately exist as a globally networked, quality-controlled non-profit archive for the benefit of science. Organizations or individuals who would like to be considered as contributors are invited to contact the EVA coordinator, Jean-Louis Romette, at jean-louis.romette@univmed.fr.


Assuntos
Bancos de Espécimes Biológicos/organização & administração , Pesquisa Biomédica/métodos , Virologia/métodos , Europa (Continente) , Humanos
3.
Antiviral Res ; 78(1): 37-46, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18083241

RESUMO

Life-threatening RNA viruses emerge regularly, and often in an unpredictable manner. Yet, the very few drugs available against known RNA viruses have sometimes required decades of research for development. Can we generate preparedness for outbreaks of the, as yet, unknown viruses? The VIZIER (VIral enZymes InvolvEd in Replication) (http://www.vizier-europe.org/) project has been set-up to develop the scientific foundations for countering this challenge to society. VIZIER studies the most conserved viral enzymes (that of the replication machinery, or replicases) that constitute attractive targets for drug-design. The aim of VIZIER is to determine as many replicase crystal structures as possible from a carefully selected list of viruses in order to comprehensively cover the diversity of the RNA virus universe, and generate critical knowledge that could be efficiently utilized to jump-start research on any emerging RNA virus. VIZIER is a multidisciplinary project involving (i) bioinformatics to define functional domains, (ii) viral genomics to increase the number of characterized viral genomes and prepare defined targets, (iii) proteomics to express, purify, and characterize targets, (iv) structural biology to solve their crystal structures, and (v) pre-lead discovery to propose active scaffolds of antiviral molecules.


Assuntos
Antivirais/farmacologia , Biologia Computacional , Cristalografia , Desenho de Fármacos , Genômica , Proteômica , Vírus de RNA/efeitos dos fármacos , RNA Polimerase Dependente de RNA , Replicação Viral/efeitos dos fármacos , Antivirais/química , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Humanos , Cooperação Internacional , Modelos Moleculares , Vírus de RNA/enzimologia , Vírus de RNA/patogenicidade , Vírus de RNA/fisiologia , RNA Viral/biossíntese , RNA Polimerase Dependente de RNA/antagonistas & inibidores , RNA Polimerase Dependente de RNA/química , RNA Polimerase Dependente de RNA/genética , RNA Polimerase Dependente de RNA/metabolismo
4.
Protein Expr Purif ; 20(3): 394-404, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11087679

RESUMO

Glycogen synthase kinase 3 (GSK-3), an element of the Wnt signalling pathway, plays a key role in numerous cellular processes including cell proliferation, embryonic development, and neuronal functions. It is directly involved in diseases such as cancer (by controlling apoptosis and the levels of beta-catenin and cyclin D1), Alzheimer's disease (tau hyperphosphorylation), and diabetes (as a downstream element of insulin action, GSK-3 regulates glycogen and lipid synthesis). We describe here a rapid and efficient method for the purification of GSK-3 by affinity chromatography on an immobilized fragment of axin. Axin is a docking protein which interacts with GSK-3ss, beta-catenin, phosphatase 2A, and APC. A polyhistidine-tagged axin peptide (residues 419-672) was produced in Escherichia coli and either immobilized on Ni-NTA agarose beads or purified and immobilized on CNBr-activated Sepharose 4B. These "Axin-His6" matrices were found to selectively bind recombinant rat GSK-3 beta and native GSK-3 from yeast, sea urchin embryos, and porcine brain. The affinity-purified enzymes displayed high kinase activity. This single step purification method provides a convenient tool to follow the status of GSK-3 (protein level, phosphorylation state, kinase activity) under various physiological settings. It also provides a simple and efficient way to purify large amounts of active recombinant or native GSK-3 for screening purposes.


Assuntos
Proteínas Quinases Dependentes de Cálcio-Calmodulina/isolamento & purificação , Cromatografia de Afinidade/métodos , Proteínas Repressoras , Sequência de Aminoácidos , Animais , Proteína Axina , Proteínas Quinases Dependentes de Cálcio-Calmodulina/genética , Clonagem Molecular , Quinase 3 da Glicogênio Sintase , Quinases da Glicogênio Sintase , Humanos , Dados de Sequência Molecular , Proteínas/genética , Ratos , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Células Tumorais Cultivadas
5.
Biotechnol Bioeng ; 68(2): 136-41, 2000 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-10712729

RESUMO

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a key enzyme in the glycolytic metabolism and the production of energy. This probably explains why GAPDH was evidenced as a major therapeutical target in several parasitic diseases; either as a vaccine candidate or as a target for chemotherapeutic treatments. Schistosoma mansoni GAPDH (Sm37-GAPDH) is one of the main schistosome vaccine candidates. The production of recombinant Sm37-GAPDH is essential to evaluate the ability of this molecule to induce protective immunity in animals and possibly in humans. The cDNA encoding Sm37-GAPDH has been cloned and sequenced. In addition, five B cell (including the major B-cell epitope Sm35-5) and two T cell epitopes have been localized on the molecule. Different expression systems have been evaluated in respect with the production yield and the GAPDH enzymatic activity. Some of them have led to either a high production of insoluble material (E. coli) or to an inactive enzyme (Pischia pastoris). The present article describes the production setting of rSm37-GAPDH using the baculovirus-insect cell system. Large amounts of soluble rSm37-GAPDH with enzymatic activity were obtained. Most sera from individuals living in an area endemic for S. mansoni recognised the rSm37 molecule and inhibited its catalytic activity.


Assuntos
Gliceraldeído-3-Fosfato Desidrogenases/biossíntese , Schistosoma mansoni/enzimologia , Esquistossomose/prevenção & controle , Animais , Baculoviridae/genética , Western Blotting , Células Cultivadas , Cromatografia em Gel , DNA Recombinante/genética , Eletroforese em Gel de Poliacrilamida , Ensaio de Imunoadsorção Enzimática , Gliceraldeído-3-Fosfato Desidrogenases/imunologia , Gliceraldeído-3-Fosfato Desidrogenases/isolamento & purificação , Humanos , Soros Imunes , Lepidópteros/citologia , Proteínas Recombinantes/biossíntese , Schistosoma mansoni/imunologia , Esquistossomose/imunologia , Vacinas Sintéticas/biossíntese
6.
Protein Expr Purif ; 14(1): 23-30, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9758747

RESUMO

Recombinant human gastric lipase (rHGL) (EC 3.1.1.3) was produced on a large scale (5-13 mg/liter) from recombinant baculovirus-infected insect cells using a bioreactor apparatus. Here an improved procedure is described for purifying rHGL involving the use of cation exchange chromatography followed by immunoaffinity column methods, which gives a total yield of 62% and a purification factor of 464, using 10% isopropanol in all the purification buffers. The presence of isopropanol was necessary to preserve the stability of the enzyme during the chromatographic separation steps. The specific activity of rHGL on tributyroylglycerol (700 U/mg) was lower than that of native HGL (nHGL) (1080 U/mg). The rHGL interfacial adsorption kinetics were studied by recording the changes in the surface pressure with time in the presence or absence of an egg phosphatidycholine monomolecular film spread at the air/water interface at various initial surface pressures. The surface behavior of rHGL was similar to that of nHGL. It can be concluded that the lipid binding affinity of rHGL is identical to that of the native lipase and, consequently, that the presence of detergents and lipids in the insect cell culture media did not affect the interfacial behavior of the purified rHGL. It will be therefore possible to specifically study the binding step of HGL mutants to a lipid monolayer.


Assuntos
Mucosa Gástrica/enzimologia , Lipase/isolamento & purificação , Animais , Baculoviridae/genética , Reatores Biológicos , Linhagem Celular , Cromatografia de Afinidade , Cromatografia por Troca Iônica , Diálise , Expressão Gênica , Humanos , Lipase/biossíntese , Lipase/genética , Mariposas , Fosfatidilcolinas , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Solventes
7.
Pathol Biol (Paris) ; 37(6): 720-4, 1989 Jun.
Artigo em Francês | MEDLINE | ID: mdl-2780109

RESUMO

In order to determine the best biochemical tests to detect cancer as the cause of ascites formation, ascitic fluid level of fibronectin, cholesterol, phospholipids and triglycerides were compared for 73 patients. The median values and the cut-off concentrations of these parameters were determined on 53 ascitic fluids without malignant cytology and 20 ascitic fluids characterized by a malignant cytology. The results showed that ascitic fluid fibronectin and cholesterol levels had a higher discriminating value than phospholipids and triglycerides to separate ascites caused by neoplasms. Cholesterol and fibronectin gave the same sensitivity and negative predictive value but cholesterol showed the highest specificity and positive predictive value.


Assuntos
Ascite/etiologia , Líquido Ascítico/análise , Biomarcadores Tumorais/análise , Neoplasias/complicações , Adulto , Colesterol/análise , Feminino , Fibronectinas/análise , Humanos , Cirrose Hepática/complicações , Masculino , Fosfolipídeos/análise , Valor Preditivo dos Testes , Proteínas/análise , Triglicerídeos/análise
8.
Int J Vitam Nutr Res ; 59(4): 323-8, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2634036

RESUMO

The existence of a relation between vitamin A and vitamin E and human cancers is supported by epidemiologic investigations. The aim of this study is to link the level of these vitamins to those of plasmatic protein carriers like retinol binding protein (RBP) and prealbumin (TTR), in three groups of subjects: healthy patients (n = 78), polyp (n = 34) and digestive cancer patients (n = 70). A paired t-test did not reveal any significant variation in any parameter between the polyp group and controls, but did evidence a significant decrease in serum levels of retinol (p less than 2.10(-4], RBP (p less than 2.10(-4), TTR (p less than 10(-5), and alpha-tocopherol (p less than 2.10(-3), in cancer cases as against control subjects. Comparison of RBP renal clearance and retinol tissue clearance in cancer and healthy patients indicates that the decrease in circulating retinol levels cannot be attributed to an increase in peripheral consumption. The simultaneous reduction of RBP and TTR serum levels is to be considered as a sign of protein denutrition. Thus our results suggest that the decrease serum levels of vitamins A and E observed in digestive cancers are a consequence of this nutritional deficiency.


Assuntos
Neoplasias do Sistema Digestório/metabolismo , Pré-Albumina/metabolismo , Proteínas de Ligação ao Retinol/metabolismo , Vitamina A/sangue , Vitamina E/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Pólipos do Colo/metabolismo , Feminino , Humanos , Rim/metabolismo , Masculino , Taxa de Depuração Metabólica , Pessoa de Meia-Idade , Vitamina A/metabolismo , Vitamina E/metabolismo
10.
Biotechnol Bioeng ; 30(9): 1001-5, 1987 Dec 20.
Artigo em Inglês | MEDLINE | ID: mdl-18581543

RESUMO

Since a stable alcohol oxidase with a high specific activity is not commercially available, we propose to produce and purify this enzyme from a strain of the yeast Hansenula polymorpha. This alcohol oxidase was immobilized into a gelatin matrix and its activity was estimated by a pO(2) sensor. The enzyme electrode obtained was then used in a continuous flow system to measure methanol or ethanol concentrations. The sample oxygen content dependence of the signal was minimized by the support properties. Measuring time for each sample were less than two minutes including response data treatment and rinsing step. The enzyme electrode response was set for ethanol from 0.5mM to 15mM and for methanol from 10mM to 300mM. On repeated use, the electrode signal for 10mM of ethanol was stable for at least 500 assays. Analysis have been performed in different beverages such as wine and beer, and the results compared to those obtained with classical methods of analysis.

11.
Pathol Biol (Paris) ; 34(9): 1006-12, 1986 Nov.
Artigo em Francês | MEDLINE | ID: mdl-2433674

RESUMO

Inflammation can be considered as a reactional process towards an injury of any etiology. It is clinically characterized by the four major points described by Celse. The symptoms are usually associated with fever and with a biological syndrome including an increased sedimentation rate related to an elevation of inflammatory plasma proteins. The Acute Phase Reactant Proteins (orosomucoid, alpha 1-antitrypsin, alpha 1-antichymotrypsin, haptoglobin, ceruloplasmin, C reactive protein and fibrinogen) are released by the hepatocytes. The complement components C3 and C4, transferrin and alpha 2-macroglobulin can also be generated by the macrophages. At inflammation sites, the activated host phagocytes release a Leukocytic Endogenous Mediator (LEM) or Interleukin I. A circulating cleavage product of Interleukin I, called "Proteolysis Inducing Factor" induces an increased muscle proteolysis and hepatic amino acids uptake for inflammatory proteins synthesis, principaly in the form of Acute Phase Reactant Proteins. Furthermore, this monokin stimulates the T4 helpers lympocytes production of a lymphokin: Interleukin II. There is no "inflammation protein" characterized by the 5 criteria of the Clinical Biology French Society. Therefore the association of a high turn over protein (CRP) and a low turn over one (orosomucoid and/or haptoglobin) is usefull for the detection of an inflammatory process and to evaluate a therapeutic efficiency. These proteins are usually selected for early diagnosis of neonatal bacterial infections and for the diagnosis of myocardial infarction. In the present time, numerous studies using statistical methods try to separate inflammatory processes according to their etiology.


Assuntos
Proteínas Sanguíneas/metabolismo , Inflamação/sangue , Proteínas de Fase Aguda/sangue , Infecções Bacterianas/sangue , Humanos , Interleucina-1/fisiologia , Interleucina-2/fisiologia , Fígado/metabolismo , Macrófagos/metabolismo , Infarto do Miocárdio/sangue , Fagócitos/metabolismo
12.
Appl Biochem Biotechnol ; 12(1): 1-15, 1986 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-3518628

RESUMO

The respiratory chain (membranous, multienzymatic system) from Escherichia coli, was coimmobilized with gelatin and insolubilized in film form by tanning with glutaraldehyde. The film was fixed onto an oxygen sensor. The enzyme electrode can be used for measuring NAD(P)H, D- and L-lactate, succinate, L-malate, 3-glycerophosphate, or pyruvate. The range of metabolites concentrations was from 1 to 50 mM. It was possible to discriminate between the different metabolites (if mixed): By inducing during bacterial growth the specific flavoproteins necessary for L-lactate, succinate, L-malate, and 3-glycerophosphate respirations. The constitutive activities are unaltered on glucose or glycerol, namely D-lactate, NAD(P)H, and pyruvate respiration. When intact bacteria were immobilized (with or without induction), D- and L-lactate, succinate, 3-glycerophosphate, and L-malate respiration were measured, no activities of pyruvate and NAD(P)H respiration were obtained. For these last activities, French press breakage (see section on Membrane Preparations) of bacteria prior to immobilization was necessary. Products of reactions can be used as enzyme inhibitors: Pyruvate inhibits D- and L-lactate; fumarate inhibits succinate, and oxaloacetate inhibits L-malate respirations. Heat denaturation of the bacteria at 55 degrees C for 1 h maintains full activity of succinate and pyruvate respiration. On the other hand, no activity of D- and L-lactate, L-malate, or NAD(P)H respiration was measurable. These enzyme electrodes have many applications in basic and applied research.


Assuntos
Enzimas Imobilizadas/metabolismo , Escherichia coli/enzimologia , Glicerofosfatos/análise , Lactatos/análise , Malatos/análise , NADP/análise , NAD/análise , Consumo de Oxigênio , Piruvatos/análise , Succinatos/análise , Eletrodos , Complexos Multienzimáticos/metabolismo , Oxirredução
13.
Pathol Biol (Paris) ; 33(7): 781-6, 1985 Sep.
Artigo em Francês | MEDLINE | ID: mdl-3936007

RESUMO

Thyroxin binding prealbumin (TBPA) and retinol binding protein (RBP) are associated in a complex responsible for the transport of vitamin A and of about 10% of the thyroid hormones T3 and T4. Both are synthetized in the liver. RBP can be characterized by two essential points: its hepatic secretion depending on the nutritional vitamin A status explains the close relation noted between these two parameters; its catabolism located in the renal tubular cells indicates the important role played by kidney in its metabolism. The concentrations, in serum of normal healthy adults, of TBPA and RBP are respectively 323 mg/l and 63 mg/l for men, 283 mg/l and 52 mg/l for women. In these cases the variations of the two proteins are significantly correlated. In patients with liver diseases and with protein deficiency, there is a lack of synthesis of TBPA and RBP (deficiency in substrate and/or decrease in hepatic synthesis). In vitamin A deficiency and in renal failure, RBP alone is disturbed.


Assuntos
Proteínas de Ligação ao Retinol/fisiologia , Proteínas de Ligação a Tiroxina/fisiologia , Envelhecimento , Androgênios/farmacologia , Animais , Transporte Biológico , Fenômenos Químicos , Química , Estrogênios/farmacologia , Feminino , Feto/metabolismo , Glucocorticoides/farmacologia , Hepatite/metabolismo , Humanos , Infecções/metabolismo , Inflamação/metabolismo , Nefropatias/metabolismo , Fígado/metabolismo , Hepatopatias Alcoólicas/metabolismo , Neoplasias Hepáticas/metabolismo , Substâncias Macromoleculares , Masculino , Peso Molecular , Prognóstico , Deficiência de Proteína/diagnóstico , Deficiência de Proteína/metabolismo , Deficiência de Proteína/terapia , Doenças da Glândula Tireoide/metabolismo , Tiroxina/sangue , Vitamina A/sangue , Deficiência de Vitamina A/metabolismo , Zinco/farmacologia
14.
Clin Chim Acta ; 136(1): 19-28, 1984 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-6362919

RESUMO

The present report gives preliminary results of a new sensitive method for the amperometric determination of antigens in serum. This method, developed from the biological model 'hepatitis B surface antigen antibodies' is less time-consuming than most immunochemical techniques, and eliminates many inconveniences arising from use of isotopes. Specific antibodies immobilised onto a gelatin membrane are applied in a solid phase 'sandwich' procedure. The antibodies are labelled with glucose oxidase. The measurement consists of an immunological process and an enzymatic reaction. The second part is carried out by fixing the active membrane onto a pO2 electrode. The sensor is immersed in a standard glucose solution and a signal is obtained by measuring the consumption of oxygen due to the enzyme reaction. This response is correlated to the antigen concentration of the sample. It is a function of both the diffusional and the reactional characteristics of the active layer. Under software conditions, the signal is sampled when the stationary state is obtained. The difference between initial signal and the stationary state signal is measured and compared with the pre-set calibration curve. Use of the computerised enzyme immunosensor could easily be extended to assay of other antigens and haptens that are usually determined by radioimmunoassay.


Assuntos
Antígenos de Superfície da Hepatite B/análise , Técnicas Imunoenzimáticas/instrumentação , Formação de Anticorpos , Antígenos/análise , Computadores , Eletrodos , Enzimas Imobilizadas , Glucose Oxidase/imunologia , Haptenos/análise , Humanos , Concentração de Íons de Hidrogênio
15.
Ann Biol Clin (Paris) ; 42(3): 227-9, 1984.
Artigo em Francês | MEDLINE | ID: mdl-6433753

RESUMO

Prealbumin was determined by radial immunodiffusion and laser immunonephelometry methods in serum or plasma from 86 adult subjects. Both methods were reliable in physiologic prealbumin range but immunonephelometry only was reliable for lower levels. Physiologic prealbumin level was 346 +/- 67 mg/l in adult males and 319 +/- 48 mg/l in adult females; no difference was noted for retinol binding protein (60 +/- 14 mg/l). When prealbumin and retinol binding protein levels were low, no close correlation was noted in their variations.


Assuntos
Pré-Albumina/análise , Proteínas de Ligação ao Retinol/análise , Adulto , Humanos , Imunodifusão , Lasers , Nefelometria e Turbidimetria , Proteínas Plasmáticas de Ligação ao Retinol
16.
Biotechnol Bioeng ; 25(11): 2557-66, 1983 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-18548593

RESUMO

L-Lysine alpha-oxidase from Trichoderma viride Y244-2 is immobilized in a gelatin support and fixed on a pO(2) sensor. The enzyme electrode obtained is used in a continuous flow system in order to measure the concentration of L-lysine in a fermentor. The sample oxygen-content dependance of the signal is minimized because of the enzyme support properties. The enzyme electrode response is set for lysine concentration from 0.2mM to 4mM. The specificity of lysine is tested with other amino acids. The enzyme membrane for lysine electrode can be used 3000 times or stored six months with good stability.

17.
Biotechnol Bioeng ; 25(3): 845-55, 1983 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-18548697

RESUMO

A numerical treatment of the signal produced by an electrode onto which an artificial enzyme membrane is mounted can give the concentration of the substrate (glucose, saccharose, lactose, amino acids, etc.) in solution. In the example of a glucose analyzer, in which glucose oxidase catalyzes the oxidation of glucose, the computer receives pO(2) level data from the electrode and calculates the glucose concentration. The transient electrode signal, measured as the enzyme membrane is exposed to a solution of glucose, is least-square approximated by a third-degree polynomial whose slope at inflection point is characteristic of the external glucose concentration. A calibration procedure provides a cubic spline approximation of glucose concentration as a function of slope, thus enabling automatic measurement of samples. The computer performs the calculations, and actuates valves for air rinsing, introduction of the sample, and water rinsing.

18.
Biotechnol Bioeng ; 25(2): 329-40, 1983 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-18548654

RESUMO

Lysine decarboxylase (L-lysine carboxylyase, E.C.4.1.1.18) is immobolized on a carbon dioxide gas-sensing electrode, by copolymerization with gelatin using the bifuncitional agent glutaraldehyde. The enzyme electrodes thus prepared are used in a continuous flow system to measure the concentration of L-lysine in a mixture of amino acids. The measuring time for each sample is about 3 min, including response and rinsing times. The electrode response is linear between 0.01-1 g/L and has a high specificity for L-lysine. The enzyme electrode response to lysine at concentrations below 0.5 g/L is stable on repeated use for at least 500 assays.

19.
Ann Biol Clin (Paris) ; 40(3): 173-9, 1982.
Artigo em Francês | MEDLINE | ID: mdl-6753649

RESUMO

The present study was carried out on 76 industrial workers divided in four working sections and exposed to cadmium and copper fumes and/or dust for periods ranging from 2 to 32 years. There were no signs of chronic copper poisoning associated with long term industrial exposure. In all cases indeed, normal blood copper level (near 15,5 mumol/l) and normal urine copper level (53 mumol/mol creat) were found. Moreover, in the plasma, the copper/ceruloplasmin ratio was approximately 8, with both normal values in micromoles. The great elimination of copper in feces assured probably the copper homeostasis. On the contrary, particularly near the furnace, the atmospheric cadmium level was to be considered; 9 out of 11 furnacemen who worked during more than 5 years showed neither respiratory or hepatic failure nor bone mineral metabolism disturbances, in spite of urine cadmium level greater than 10 mumol/mol creat, "early warning" for renal damage. There was no significant correlation between urine and blood cadmium levels when the latter was greater than 4,5 micrograms/l (40,2 nmol/l). The high beta 2 microglobulin level for 66 p. cent of furnacemen, was the indicator of tubular damage. Therefore the urine cadmium in combination with beta 2m should be determined to detect early effects of cadmium in exposed workers.


Assuntos
Cádmio/metabolismo , Cobre/metabolismo , Exposição Ambiental , Poluentes Ocupacionais do Ar/análise , Cádmio/efeitos adversos , Ceruloplasmina/análise , Cobre/efeitos adversos , Poeira/análise , Feminino , Humanos , Túbulos Renais/efeitos dos fármacos , Masculino , Microglobulina beta-2/análise
20.
Nouv Presse Med ; 11(4): 271-4, 1982 Jan 30.
Artigo em Francês | MEDLINE | ID: mdl-7058150

RESUMO

Copper is an essential dietary component, being the coenzyme of many enzymes with oxidase activity, e.g. ceruloplasmin, superoxide dismutase, monoamine oxidase, etc. The metabolism of copper is complex and imperfectly known. Active transport of copper through the intestinal epithelial cells involves metallothionein, a protein rich in sulfhydryl groups which also binds the copper in excess and probably prevents absorption in toxic amounts. In hepatocytes a metallothionein facilitates absorption by a similar mechanism and regulates copper distribution in the liver: incorporation in an apoceruloplasmin, storage and synthesis of copper-dependent enzymes. Metallothioneins and ceruloplasmin are essential to adequate copper homeostasis. Apart from genetic disorders, diseases involving copper usually result from hypercupraemia of varied origin. Wilson's disease and Menkes' disease, although clinically and pathogenetically different, are both marked by low ceruloplasmin and copper serum levels. The excessive liver retention of copper in Wilson's disease might be due to increased avidity of hepatic metallothioneins for copper and decreased biliary excretion through lysosomal dysfunction. Menkes' disease might be due to low avidity of intestinal and hepatic metallothioneins for copper. The basic biochemical defect responsible for these two hereditary conditions has not yet been fully elucidated.


Assuntos
Cobre/metabolismo , Doenças Metabólicas/metabolismo , Adolescente , Adulto , Ceruloplasmina/metabolismo , Criança , Cobre/sangue , Degeneração Hepatolenticular/metabolismo , Humanos , Infecções/sangue , Inflamação/sangue , Absorção Intestinal , Fígado/metabolismo , Síndrome dos Cabelos Torcidos/metabolismo , Metalotioneína/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...