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1.
Glob Health Action ; 12(1): 1609313, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31116096

RESUMO

Background: Community-based approaches have been identified as an effective strategy to address the growing burden of noncommunicable diseases (NCDs) worldwide. However, little is known about community as a concept among people living in socioeconomically disadvantaged settings and stakeholders' interactions and engagement in NCDs prevention and management. Objective: The aim of this study was to understand; (1) the meaning of community among people living in socioeconomically disadvantaged suburbs in Region Stockholm and (2) how communities interact and engage with stakeholders at local and regional levels for the prevention and management of type 2 diabetes (T2D). Methods: This qualitative study was conducted in three municipalities in Region Stockholm with a high proportion of migrants. Multiple data collection methods were used, including observations of community activities; interviews with community members, representatives of public authorities and NGOs; and group interviews with healthcare providers. Data were analyzed using content analysis. Results: Community was perceived as living in close proximity with shared beliefs, values and resources. Although they recognized its social and cultural diversity, community members focused more on the commonalities of living in their neighborhood and less on their differences in country of birth and languages spoken. Several mismatches between awareness of community needs and the available skills and resources among stakeholders for T2D prevention were identified. Stakeholders expressed awareness of T2D risk and interest in addressing it in a culturally appropriate manner. Conclusion: Interaction between the communities and stakeholders was limited, as was engagement in T2D prevention and management. This highlights barriers in the collaboration between community, healthcare institutions and other stakeholders which consequently affect the implementation of preventive interventions. Innovative ways to link the community to the healthcare sector and other local government institutions are needed to build the capacity of health systems for T2D prevention in socioeconomically disadvantaged communities.


Assuntos
Serviços de Saúde Comunitária/organização & administração , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/prevenção & controle , Promoção da Saúde/organização & administração , Colaboração Intersetorial , Populações Vulneráveis/psicologia , Populações Vulneráveis/estatística & dados numéricos , Adulto , Idoso , Idoso de 80 Anos ou mais , Diabetes Mellitus Tipo 2/psicologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pesquisa Qualitativa , Fatores Socioeconômicos , Suécia
2.
Med Health Care Philos ; 3(3): 297-304, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11200030

RESUMO

One problematic aspect of the rationality of medical practice concerns the relation between expert knowledge and non-expert knowledge. In medical practice it is important to match medical knowledge with the self-knowledge of the individual patient. This paper tries to study the problem of such matching by describing a model for technological paradigms and comparing it with an ideal of technological rationality. The professionalised experts tend to base their decisions and actions mostly on medical knowledge while the rationality of medicine also involves just as important elements of the personal evaluation and knowledge of the patients. Since both types of knowledge are necessary for rational decisions, the gap between the expert and the non-expert has to be bridged in some way. A solution to the problem is suggested in terms of pluralism, with the patient as ultimate decision-maker.


Assuntos
Tomada de Decisões , Participação do Paciente , Relações Médico-Paciente , Tecnologia Biomédica , Competência Clínica , Ética Médica , Conhecimentos, Atitudes e Prática em Saúde , Humanos , Resolução de Problemas , Terapêutica/métodos
3.
Theor Med Bioeth ; 20(3): 229-44, 1999 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-10474310

RESUMO

A suitable demarcation between pure science and applied research can be drawn in terms of their goals. This distinction of goals has methodological and cultural consequences. If the demarcation is accepted, what does the connection between the two enterprises look like? What is the role of science in medical practice? The Baconian answer to this question is discussed and criticised as too linear. A second answer may be that pure science has no part at all in medicine. This too can be criticised as too simplistic. A third answer is suggested in which pure science plays the role of being an instrument for interpreting observations and problems, and of being a source of inspiration for technological research programs.


Assuntos
Ciência de Laboratório Médico , Medicina , Prática Profissional , Pesquisa , Ciência , Humanos , Modelos Teóricos
4.
Theor Med Bioeth ; 20(2): 105-23, 1999 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-10450662

RESUMO

Should medicine be defined as the enterprise in charge of the health problems of society? If so, then any problem (individual, public, social or political) that can be reformulated as a "health problem" could serve as a goal of medicine. If, on the other hand, medicine--or medicine proper--is defined in terms of some limited goal and limited means, then some medical professionals would find themselves working in other fields than medicine. It could be of some importance to the patient to know whether the medical professional he meets is engaged in medical practice (aiming at the patient's health), research, public health or some other project which involves medical competence. Obviously, some of these enterprises may have conflicting goals. This paper will analyse various candidates for being a model of medicine, discuss some of the consequences, and argue for a limited view of medical practice.


Assuntos
Medicina , Objetivos Organizacionais , Filosofia Médica , Prática Profissional , Papel Profissional , Humanos , Modelos Organizacionais , Papel do Profissional de Enfermagem , Saúde Pública , Pesquisa , Alocação de Recursos
5.
Biochem Mol Med ; 55(1): 77-9, 1995 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7551831

RESUMO

Treatment with pivalic acid containing prodrugs has been shown to cause carnitine depletion by loss of pivaloyl carnitine in urine. A 7-day standard pivmecillinam treatment of adults lead to a marked decrease of the free serum carnitine concentration (44.6 to 12.9 mumol/liter), whereas no change was seen in those given norfloxacine (40.0 to 40.5 mumol/liter). In some patients irrespective of age the free serum carnitine concentration was decreased to levels (around 10 mumol/liter) at which an impaired ketone-body production may occur. Therefore, there is reason for cautious use of this type of drug irrespective of the age of the patients.


Assuntos
Andinocilina Pivoxil/efeitos adversos , Carnitina/sangue , Penicilinas/efeitos adversos , Ácidos Pentanoicos/efeitos adversos , Adolescente , Adulto , Fatores Etários , Idoso , Andinocilina Pivoxil/administração & dosagem , Carnitina/deficiência , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Norfloxacino/administração & dosagem , Penicilinas/administração & dosagem , Ácidos Pentanoicos/administração & dosagem , Pró-Fármacos/administração & dosagem , Pró-Fármacos/efeitos adversos , Fatores de Risco , Fatores de Tempo , Infecções Urinárias/tratamento farmacológico
6.
Biochem Med Metab Biol ; 52(1): 18-21, 1994 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7917463

RESUMO

Long-term treatment with pivalic acid prodrug results in impaired ketone-body production. Therefore, it was of interest to investigate whether short-term treatment had any influence on the fatty acid oxidation. In this study six healthy males were given 1200 mg per day of pivmecillinam for 12 days to induce carnitine deficiency. The concentration of free carnitine in serum was reduced from a mean of 42.8 mumol/liter (range, 31-48) to 11.6 mumol/liter (range, 7.0-24), but the muscle carnitine concentration was not reduced. A 36-h fasting test was performed before and after drug administration to study the effect on ketone-body production. After treatment, the two subjects with the lowest level of serum free carnitine at the end of the fasting period had impaired ketogenesis. This indicates a carnitine deficiency in the liver which was reflected in the free carnitine concentration for by mobilization of muscle carnitine. We conclude that there is a substantial risk to develop carnitine deficiency and impaired fatty acid oxidation in the liver during short-term treatment with drugs conjugated with pivalic acid.


Assuntos
Carnitina/deficiência , Corpos Cetônicos/biossíntese , Ácidos Pentanoicos/farmacologia , Pró-Fármacos/farmacologia , Adulto , Andinocilina Pivoxil/farmacologia , Carnitina/sangue , Carnitina/metabolismo , Ácidos Graxos/metabolismo , Ácidos Graxos não Esterificados/sangue , Humanos , Fígado/metabolismo , Masculino , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/metabolismo , Oxirredução
7.
Eur J Biochem ; 213(3): 1075-80, 1993 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-8504802

RESUMO

gamma-Butyrobetaine hydroxylase is a 2-oxoglutarate-dependent dioxygenase that catalyzes the hydroxylation of gamma-butyrobetaine to carnitine, the last step in the biosynthesis of carnitine from lysine. The primary structure of the enzyme from Pseudomonas sp. AK1 has been determined. Sequence analysis of the intact protein and of peptides from essentially three different digests established the presence of a peptide chain containing 383 residues, and an N-terminal truncated form of 382 residues. The two chains have molecular masses of 43,321 Da and 43,207 Da, respectively, and are identical except for the presence or absence of an N-terminal asparagine residue; the shorter form starts with an alanine residue. In preparations of the dimeric protein, the two chains occur in an approximate ratio of 1:1. There are nine cysteine residues and 13 histidine residues, i.e. amino acids which have been postulated as ligands for iron binding. In spite of functional similarities, there appears to be no clear sequence similarities with any of the other mammalian 2-oxoglutarate-dependent dioxygenases so far characterized.


Assuntos
Oxigenases de Função Mista/química , Pseudomonas/enzimologia , Sequência de Aminoácidos , Aminoácidos/análise , Humanos , Rim/enzimologia , Dados de Sequência Molecular , Análise de Sequência , gama-Butirobetaína Dioxigenase
8.
Scand J Clin Lab Invest ; 52(5): 361-72, 1992 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-1514015

RESUMO

Treatment of 17 children aged 2-9.5 years with a combination of pivmecillinam and pivampicillin (250-500 mumol 24 h-1) for more than 1 year resulted in a reduction of the free carnitine concentration in serum and muscle to less than 10% of the mean reference value. The decline in serum was slow, with an estimated half-life of about 5 months. Spontaneous replenishment occurred at about the same slow rate. Thus, there is no increase in endogenous carnitine synthesis as a response to increased demand of carnitine for detoxification. Supplementation with carnitine during treatment required at least a four-fold molar excess over pivalic acid to achieve and sustain a normal carnitine concentration. The replenishment of carnitine occurred with a half-life of 1.1-3.0 months. From determination of muscle-carnitine concentration in patients treated with pivaloyl-containing antibiotics and in patients with organic aciduris, we conclude that serum carnitine is a good predictor of carnitine stores in the body. Six non-supplemented patients with a serum free-carnitine concentration of 0.7-2.6 mumol l-1 had an inadequate ketone-body increase during a 24-h fast. Vomiting, nausea and tiredness occurred in three cases following the fasting period. After normalization of the serum-carnitine concentration, a normal response to fasting was observed. Thus, in some organic acidurias, for example medium-chain acyl-CoA dehydrogenase deficiency, a low liver concentration of carnitine may be an important contributing factor to hypoglycaemic and Reye-like attacks. We believe that prodrugs which contain pivalic acid should be avoided if acceptable alternatives exist. If used, supplementation with at least four-fold molar excess of carnitine is advisable.


Assuntos
Andinocilina Pivoxil/efeitos adversos , Carnitina/deficiência , Jejum/fisiologia , Ácidos Pentanoicos/efeitos adversos , Pivampicilina/efeitos adversos , Pró-Fármacos/efeitos adversos , Andinocilina Pivoxil/administração & dosagem , Carnitina/metabolismo , Criança , Pré-Escolar , Feminino , Homeostase , Humanos , Músculos/metabolismo , Pivampicilina/administração & dosagem , Valores de Referência
9.
Lancet ; 2(8661): 469-73, 1989 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-2570185

RESUMO

Short-term administration of pivampicillin and pivmecillinam resulted in a reduction of serum carnitine concentration and an increase in excretion of acylcarnitine in urine. These changes persisted for more than ten days after cessation of therapy. In seven girls on long-term treatment with a mixture of pivampicillin and pivmecillinam the mean total serum carnitine concentration fell to 15% (7-27%) of pretreatment values. The acylcarnitine fraction was 11-57% of total carnitine, compared with less than 2% before treatment. Muscle carnitine concentrations in two girls treated with the antibiotics for 22 and 30 months were only 10% of the mean reference value. These concentrations in serum and muscle are in the range encountered in patients with carnitine deficiencies of other aetiologies in which life-threatening metabolic crises may arise. The risk of adverse effects from prodrugs that give rise to pivalic acid should be seriously considered, particularly in patients under metabolic stress.


Assuntos
Andinocilina Pivoxil/efeitos adversos , Andinocilina/efeitos adversos , Ampicilina/análogos & derivados , Carnitina/deficiência , Pivampicilina/efeitos adversos , Adolescente , Adulto , Andinocilina Pivoxil/administração & dosagem , Carnitina/análise , Carnitina/urina , Criança , Pré-Escolar , Cromatografia Gasosa/métodos , Cromatografia Líquida de Alta Pressão/métodos , Esquema de Medicação , Avaliação de Medicamentos , Quimioterapia Combinada , Feminino , Humanos , Lactente , Masculino , Espectrometria de Massas/métodos , Músculos/análise , Ácidos Pentanoicos/metabolismo , Pivampicilina/administração & dosagem , Fatores de Tempo , Infecções Urinárias/sangue , Infecções Urinárias/tratamento farmacológico , Infecções Urinárias/urina
10.
J Inherit Metab Dis ; 12(2): 108-11, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2502670

RESUMO

Carnitine uptake has been studied in fibroblasts from a case of hereditary carnitine deficiency and in relatives. There was no evidence for carrier-dependent uptake in cells from the patient. The mother and probably the healthy sister had an impaired uptake. The results show that the defect in this form of carnitine deficiency is an inability to establish a concentration gradient over the cell membrane.


Assuntos
Carnitina/deficiência , Carnitina/metabolismo , Transporte Biológico , Carnitina/genética , Células Cultivadas , Feminino , Fibroblastos/metabolismo , Humanos , Cinética , Mutação
12.
J Med Chem ; 29(10): 1953-61, 1986 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-3020249

RESUMO

The synthesis and angiotensin converting enzyme (ACE) inhibiting activities of quinapril (CI-906, 22), its active diacid (CI-928, 33), and its dimethoxy analogue (CI-925, 25) are reported. These tetrahydro-3-isoquinolinecarboxylic acid derivatives possess equivalent in vitro potency and in vivo efficacy to enalapril. Sulfhydryl analogues with the same structural variation are also highly potent. In contrast, tetrahydro-1-isoquinolinecarboxylic acid and homologous isoindoline-1-carboxylic acid analogues show a striking divergence in potency between the two types, sulfhydryl analogues being essentially inactive, while non-sulfhydryl analogues are equipotent with the proline prototype. This is the first evidence suggesting that alternate binding modes may exist for the two major structural classes of small molecule ACE inhibitors.


Assuntos
Inibidores da Enzima Conversora de Angiotensina , Isoquinolinas/síntese química , Tetra-Hidroisoquinolinas , Animais , Isoquinolinas/farmacologia , Masculino , Conformação Molecular , Quinapril , Ratos , Ratos Endogâmicos , Relação Estrutura-Atividade , Compostos de Sulfidrila/farmacologia
13.
J Med Chem ; 28(5): 606-12, 1985 May.
Artigo em Inglês | MEDLINE | ID: mdl-2859371

RESUMO

On the basis of a structural model of the postsynaptic dopaminergic antagonist pharmacophore, a series of 1-[3-(diarylamino)propyl]piperidines and related compounds was synthesized and evaluated for potential antipsychotic activity. For a rapid measure of activity, the target compounds were initially screened in vitro for inhibition of [3H]haloperidol binding and in vivo in a test of locomotor activity. Behavioral efficacy of compounds identified from the initial screens was more accurately measured in rats by using a suppression of high base-line medial forebrain bundle self-stimulation test model. The propensity of these compounds for causing extrapyramidal side effects was evaluated by using a rat catalepsy method. On the basis of these test models, we have shown that the methine carbon of the 1-(4,4-diarylbutyl)piperidines can be advantageously replaced with a nitrogen atom. The 1-[3-(diarylamino)propyl]piperidines were less cataleptic than the corresponding 1-(4,4-diarylbutyl)piperidines. The compounds with the widest separation between efficacious dose and cataleptic dose are 8-[3-[bis(4-fluorophenyl)amino]propyl]-1-phenyl-1,3,8-triazaspiro [4. 5]decan-4-one (6), 1-[1-[3-[bis(4-fluorophenyl)amino]propyl]-4-piperidinyl]-1,3-dihydro- 2H-benzimidazol-2-one (11), 1-[1-[3-[bis(4-fluorophenyl)amino]propyl]-1,2,3,6-tetrahydro-4- pyridinyl]-1,3-dihydro-2H-benzimidazol-2-one (22), and 1-[3-[bis(4-fluorophenyl)amino]propyl]-4-(2-methoxyphenyl)piperazine (26).


Assuntos
Antipsicóticos/síntese química , Catalepsia/induzido quimicamente , Piperidinas/síntese química , Animais , Antipsicóticos/toxicidade , Doenças dos Gânglios da Base/induzido quimicamente , Ligação Competitiva , Corpo Estriado/metabolismo , Haloperidol/metabolismo , Humanos , Técnicas In Vitro , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Piperazinas/síntese química , Piperazinas/farmacologia , Piperazinas/toxicidade , Piperidinas/farmacologia , Piperidinas/toxicidade , Ratos , Receptores Dopaminérgicos/efeitos dos fármacos , Receptores Dopaminérgicos/metabolismo , Autoestimulação/efeitos dos fármacos , Relação Estrutura-Atividade
14.
Biochem J ; 223(1): 119-27, 1984 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-6497835

RESUMO

gamma-Butyrobetaine hydroxylase [4-trimethylaminobutyrate, 2-oxoglutarate:oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1] from human kidney was resolved into three forms by chromatofocusing. After further chromatography on an anion-exchanger, each form appeared as a single band on electrophoresis in polyacrylamide gel containing sodium dodecyl sulphate. The isoelectric points of isoenzymes 1, 2 and 3 were 5.6, 5.7 and 5.8 respectively, as estimated by isoelectric focusing. Their specific activities were 17-29 mu kat/g of protein. The concentrations of the three isoenzymes were about equal, possibly slightly lower for isoenzyme 1. The requirement for Fe2+ and the Km values for gamma-butyrobetaine and 2-oxoglutarate were about the same for the different enzyme forms. L- and D-Carnitine caused decarboxylation of 2-oxoglutarate to the same extent (8 and 29%) with the three forms. The enzyme forms had the same mass, 64 kDa, as determined by gel filtration in nondenaturing media. The same subunit mass, 42 kDa, was obtained for the multiple forms by electrophoresis in polyacrylamide gels containing sodium dodecyl sulphate. Isoenzyme 2 was resolved into two protein bands by isoelectric focusing in polyacrylamide gels containing urea. Isoenzyme 1 contained only one of these bands and isoenzyme 3 the other. The three enzyme forms of gamma-butyrobetaine hydroxylase thus appear to be dimeric combinations of two subunits differing in charge but not in size. gamma-Butyrobetaine hydroxylase from crude extracts of human, rat and calf liver was also separated into multiple forms by a chromatofocusing technique. The isoenzyme pattern was the same in human liver and kidney. The technique used to resolve the mammalian enzymes gave no evidence for the presence of multiple forms of the bacterial enzyme from Pseudomonas sp. AK 1.


Assuntos
Isoenzimas , Oxigenases de Função Mista , Animais , Bovinos , Cromatografia por Troca Iônica , Cromatografia Líquida , Eletroforese em Gel de Poliacrilamida , Humanos , Isoenzimas/isolamento & purificação , Rim/enzimologia , Cinética , Fígado/enzimologia , Oxigenases de Função Mista/isolamento & purificação , Oxigenases de Função Mista/metabolismo , Pseudomonas/enzimologia , Ratos , Especificidade da Espécie , gama-Butirobetaína Dioxigenase
15.
J Med Chem ; 27(5): 684-91, 1984 May.
Artigo em Inglês | MEDLINE | ID: mdl-6716406

RESUMO

A series of N-[(dialkylamino)alkyl]-2-oxo-1- pyrrolidineacetamides was synthesized. The title compounds reversed electroconvulsive shock (ECS) induced amnesia in mice when administered subsequent to the ECS treatment and were inactive in a general observational test for central nervous system (CNS) activity. Active compounds exhibited an inverted U-shaped dose-response curve. Among the compounds with the broadest dose-response curve, as well as the most potent, were those with the N-[2-[bis(1-methylethyl)amino] ethyl] or 2,6- dimethylpiperidinoethyl residues as amide substituent. The N-(dialkylamino) substituent markedly enhances amnesia-reversal activity, with ethylene providing the optimal chain length. N-[2-[Bis(1-methylethyl)amino]ethyl] -2-oxo-1- pyrrolidineacetamide N-(dialkylamino) substituent was selected for preclinical toxicological evaluation, assigned the investigational number CI-879 and the U.S. adopted name ( USAN ) pramiracetam . Pramiracetam demonstrated a wide margin of safety in animals and was well tolerated in normal human volunteers. It has shown encouraging activity in an open label trial in patients with primary degenerative dementia (PDD or senile dementia of the Alzheimer's type).


Assuntos
Amnésia/tratamento farmacológico , Pirrolidinas/uso terapêutico , Animais , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos , Eletrochoque , Humanos , Masculino , Camundongos , Camundongos Endogâmicos , Pirrolidinas/síntese química , Relação Estrutura-Atividade
16.
Biosci Rep ; 4(5): 433-40, 1984 May.
Artigo em Inglês | MEDLINE | ID: mdl-6428486

RESUMO

Replacement of unlabeled gamma-butyrobetaine with gamma-[2,3,4-2H6]butyrobetaine has a profound effect on the stoichiometry between decarboxylation of 2-oxoglutarate and hydroxylation in the reaction catalyzed by human gamma-butyrobetaine hydroxylase. The ratios between decarboxylation and hydroxylation are 1.16 with unlabeled and 7.48 with deuterated gamma-butyrobetaine as substrate. From these ratios an internal isotope effect of 41 has been calculated. DV in the overall reaction measured as 2- oxoglutarate decarboxylation is 2.5 and DV/K is 1.0. For gamma-butyrobetaine hydroxylase from Pseudomonas sp. AK 1, 2-oxoglutarate decarboxylation exceeds hydroxylation with 10% when deuterated gamma-butyrobetaine is used. No excess was found with unlabeled substrate and no internal isotope effect could be calculated. DV for the bacterial enzyme is 6.


Assuntos
Betaína/análogos & derivados , Oxigenases de Função Mista/metabolismo , Betaína/metabolismo , Dióxido de Carbono/biossíntese , Carnitina/biossíntese , Humanos , Rim/enzimologia , Cinética , Especificidade por Substrato , Trítio , gama-Butirobetaína Dioxigenase
17.
Scand J Clin Lab Invest ; 42(6): 477-85, 1982 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-7156861

RESUMO

The activity of gamma-butyrobetaine hydroxylase [4-trimethylaminobutyrate: oxygen oxidoreductase (3-hydroxylating), EC 1.14.11.1] was determined in different parts of a human kidney removed at surgery and in five perfused human cadaver kidneys. The activity in the 100,000 g supernatant fraction of a homogenate of whole kidneys was 48 nkat X g-1 protein (range 32-70 nkat X g-1protein). The cortex and outer medulla had four to six times higher activity than the inner medulla. A 60-fold purification from the soluble fraction of kidney homogenates with a 40% recovery was achieved by ammonium sulphate fractionation followed by DEAE-cellulose and hydroxylapatite chromatography. The enzyme had a specific activity of 2.4 mukat X g-1 protein but was contaminated to a minor degree by other proteins as judged by polyacrylamide gel electrophoresis. The Km values for gamma-butyrobetaine, 2-oxoglutarate and oxygen were 0.2 mmol/l, 0.3 mmol/l and 5.5% (by volume in the gas phase). There was an absolute requirement for ferrous ion. Half-maximal activity was reached with 10 mumol/l of Fe2+ in phosphate buffer (14 mmol/l) at pH 6.5. With a reaction time of 30 min ascorbate and catalase stimulated the reaction seven- and fivefold, respectively. Optimal pH value for the reaction was 6.2-6.5 in phosphate buffer. Decarboxylation of 2-oxoglutarate in the presence of 4-trimethylaminocrotonate or 4-dimethylaminobutyrate was 40 and 20%, respectively, of that with gamma-butyrobetaine as substrate. None of several compounds chemically related to 2-oxoglutarate, including oxaloacetate, stimulated gamma-butyrobetaine hydroxylation when tested in the absence of 2-oxoglutarate. We conclude that the requirements of the human kidney enzyme are similar to those previously reported for this enzyme from other sources.


Assuntos
Rim/enzimologia , Oxigenases de Função Mista/metabolismo , Cromatografia , Cromatografia DEAE-Celulose , Descarboxilação , Eletroforese em Gel de Poliacrilamida , Humanos , Concentração de Íons de Hidrogênio , Cinética , gama-Butirobetaína Dioxigenase
18.
Biochem J ; 205(2): 339-44, 1982 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-6291507

RESUMO

The possible role of superoxide anion in 2-oxoglutarate-coupled dioxygenase reactions has been investigated. gamma-Butyrobetaine hydroxylase (EC 1.14.11.1) was inhibited by human erythrocyte superoxide dismutase (EC 1.15.1.1), probably due to release of Cu(2+) or Zn(2+), as the inhibition was more pronounced after heat-inactivation of the dismutase and as Cu(2+) was a potent inhibitor. Bovine superoxide dismutase and the Mn(2+)-containing superoxide dismutase from Escherichia coli were not inhibitory. Superoxide anion generated from xanthine/xanthine oxidase was not stimulatory and could not replace ascorbate. Thymine 7-hydroxylase (EC 1.14.11.6) and thymidine 2'-hydroxylase (EC 1.14.11.3) were not inhibited by erythrocyte superoxide dismutase or stimulated by superoxide anion. gamma-Butyrobetaine hydroxylase was inhibited by a number of low-molecular-weight compounds, such as tetranitromethane, Nitro Blue Tetrazolium, adrenaline and Tiron, which may act as scavengers of superoxide anion. Involvement of this radical in other oxygenase reactions has been inferred from the findings that they were inhibitory for the respective enzymes. Several of these compounds also inhibited gamma-butyrobetaine hydroxylase. It could be concluded from these experiments, however, that mechanisms other than disposal of superoxide anion might equally well be operative, such as hydrophobic interaction with the enzyme protein and interaction with compounds required for full enzymic activity, e.g. iron and ascorbate. The results appear to rule out a requirement for superoxide anion generated in free solution, and have not yielded evidence for participation of enzyme-bound superoxide anion in 2-oxoglutarate-dependent hydroxylations.


Assuntos
Ácidos Cetoglutáricos/metabolismo , Oxigenases de Função Mista/metabolismo , Oxigênio/metabolismo , Superóxidos/metabolismo , Cobre/metabolismo , Hidroquinonas/metabolismo , Hidroxilação , Nitroazul de Tetrazólio/metabolismo , Quinonas/metabolismo , Superóxido Dismutase/metabolismo , Tetranitrometano/metabolismo , gama-Butirobetaína Dioxigenase
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