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2.
Int J Cardiol ; 376: 165-171, 2023 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-36738845

RESUMO

BACKGROUND: Myocarditis and inflammatory bowel diseases (IBD) are rare conditions, but may coexist. Myocarditis in IBD may be infective, immune-mediated, or due to mesalamine toxicity. A gap of knowledge exists on the clinical features of patients that present myocarditis in association with IBD, especially for endomyocardial biopsy-proven cases. Our aims are: 1) to describe the clinical characteristics of patients with an associated diagnosis of myocarditis and IBD in a single-center hospital, 2) to perform a systematic review of the literature of analogous cases. METHODS: We retrospectively analyzed data of patients followed up at the outpatient Cardio-immunology and Gastroenterology Clinic of Padua University Hospital, to identify those with an associated diagnosis of myocarditis and IBD. In addition, a systematic review of the literature was conducted. We performed a qualitative analysis of the overall study population. RESULTS: The study included 104 patients (21 from our single center cohort, 83 from the literature review). Myocarditis in IBD more frequently affects young (median age 31 years) males (72%), predominantly with infarct-like presentation (58%), within an acute phase of the IBD (67%) and with an overall benign clinical course (87%). Nevertheless, a not negligible quote of patients may present giant cell myocarditis, deserve immunosuppression and have a chronic, or even fatal course. Histological evidence of mesalamine hypersensitivity is scarce and its incidence may be overestimated. CONCLUSIONS: Our study shows that myocarditis in association with IBD, if correctly managed, may have a spontaneous benign course, but predictors of worse prognosis must be promptly recognized.


Assuntos
Doenças Inflamatórias Intestinais , Miocardite , Masculino , Humanos , Adulto , Miocardite/diagnóstico , Mesalamina , Estudos Retrospectivos , Doenças Inflamatórias Intestinais/complicações , Prognóstico
3.
J Prev Med Hyg ; 57(2): E75-80, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27582632

RESUMO

The aim of this study was the quality of service evaluation of two different organizational ways in delivering infant vaccination according to a Regional Vaccination Plan. Eleven vaccination centres were selected in two Local Health Units (ASLs) belonging to the Regional Health Service of the Lazio Region, Italy. The services offering paediatric vaccinations for children under three years of age, delivered without an appointment (VACP) or with the need for an appointment (VACL), were investigated. The quality aspects under evaluation were communicational efficiency, organisational efficiency and comfort. Subjective data were collected from different stakeholders and involve the elicitation of best and worst feasible performance conditions for the ASLs when delivering VACP/VACL services. Objective data consists in the observation of current performances of the selected vaccination centres. Quality scorecards were obtained from the combination of all data. Benchmarking between VACP and VACL, i.e., two different organisational ways in delivering infant vaccination, can be performed as a result of the probabilistic meaning of the evaluated scores. An expert of vaccination services, i.e., a virtual combination of patients, doctors and nurses, claims the quality of service delivery of the ASLs under investigation with probability 78.03% and 69.67% for VACP and VACL, respectively. In other words, for short, the quality scores of the ASLs were 78.03% for VACP and 69.67% for VACL. Furthermore our results show how to practically improve the current service delivery. The QuaVaTAR approach can result in improvements of the quality of the ASLs for the two different ways of delivering paediatric vaccinations in a simple and intuitive way.


Assuntos
Benchmarking , Programas de Imunização , Vacinação/normas , Pré-Escolar , Comunicação , Humanos , Lactente , Itália
4.
Pharmacol Res ; 78: 1-9, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24083950

RESUMO

Selective cyclooxygenase 2 (COX2) inhibitors (COXIBs) are effective anti-inflammatory and analgesic drugs with improved gastrointestinal (GI) safety compared to nonselective nonsteroidal anti-inflammatory drugs known as traditional (tNSAIDs). However, their use is associated with a cardiovascular (CV) hazard (i.e. increased incidence of thrombotic events and hypertension) due to the inhibition of COX2-dependent vascular prostacyclin. Aiming to design COX2-selective inhibitors with improved CV safety, new NO-releasing COXIBs (NO-COXIBs) have been developed. In these hybrid drugs, the NO-mediated CV effects are expected to compensate for the COXIB-mediated inhibition of prostacyclin. This study evaluates the potential CV beneficial effects of VA694, a promising NO-COXIB, the anti-inflammatory effects of which have been previously characterized in several in vitro and in vivo experimental models. When incubated in hepatic homogenate, VA694 acted as a slow NO-donor. Moreover, it caused NO-mediated relaxant effects in the vascular smooth muscle. The chronic oral administration of VA694 to young spontaneously hypertensive rats (SHRs) significantly slowed down the age-related development of hypertension and was associated with increased plasma levels of nitrates, stable end-metabolites of NO. Furthermore, a significant improvement of coronary flow and a significant reduction of endothelial dysfunction were observed in SHRs submitted to chronic administration of VA694. In conclusion, VA694 is a promising COX2-inhibiting hybrid drug, showing NO releasing properties which may mitigate the CV deleterious effects associated with the COX2-inhibition.


Assuntos
Anti-Inflamatórios não Esteroides/farmacologia , Inibidores de Ciclo-Oxigenase 2/farmacologia , Fatores Relaxantes Dependentes do Endotélio/administração & dosagem , Endotélio/efeitos dos fármacos , Hipertensão/tratamento farmacológico , Nitratos/farmacologia , Óxido Nítrico/administração & dosagem , Pirróis/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Pressão Sanguínea/efeitos dos fármacos , Vasos Coronários/efeitos dos fármacos , Inibidores de Ciclo-Oxigenase 2/química , Endotélio/patologia , Fatores Relaxantes Dependentes do Endotélio/farmacologia , Hipertensão/sangue , Masculino , Nitratos/sangue , Nitratos/química , Óxido Nítrico/farmacologia , Nitritos/sangue , Pirróis/química , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , Fluxo Sanguíneo Regional/efeitos dos fármacos
5.
Technol Cancer Res Treat ; 10(6): 585-90, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22066598

RESUMO

The purpose of this study was to evaluate rectum motion during 3-Dimensional conformal radiation therapy (3D-CRT) in prostate cancer patients, to derive a planning volume at risk (PRV) and to correlate the PRV dose-volume histograms (DVH) with treatment complications.This study was conducted in two phases. Initially, the PRV was defined prospectively in 50 consecutive prostate cancer patients (Group 1) who received a radical course of 3-D CRT. Then, the obtained PRV was used in the radiotherapy planning of these same 50 patients plus another 59 prostate cancer patients (Group 2) previously treated between 2004 and 2008. All these patients' data, including the rectum and PRV DVHs, were correlated to acute and late complications, according to the Common Toxicity Criteria (CTC) v4.0.The largest displacement occurred in the anterior axis. Long-term gastrointestinal (GI) complications grade ≥ 2 were seen in 9.2% of the cases. Factors that influenced acute GI reactions were: doses at 25% (p 5 0.011) and 40% (p 5 0.005) of the rectum volume and at 40% of the PRV (p 5 0.012). The dose at 25% of the rectum volume (p 5 0.033) and acute complications ≥ grade 2 (p 5 0.018) were prognostic factors for long-term complications. The PRV DVH did not correlate with late toxicity. The rectum showed a significant inter-fraction motion during 3D-CRT for prostate cancer. PRV dose correlated with acute gastrointestinal complications and may be a useful tool to predict and reduce their occurrence.


Assuntos
Gastroenteropatias/etiologia , Imageamento Tridimensional , Neoplasias da Próstata/patologia , Neoplasias da Próstata/radioterapia , Lesões por Radiação/etiologia , Planejamento da Radioterapia Assistida por Computador , Radioterapia Conformacional/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Neoplasias da Próstata/complicações
6.
Curr Med Chem ; 18(10): 1540-54, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21428878

RESUMO

The development of the coxib family has represented a stimulating approach in the treatment of inflammatory disorders, such as arthritis, and for the management of acute pains, in relation to the well-known traditional Non-Steroidal Anti-inflammatory Drugs (t-NSAIDs). Prompted by the pursuit for new cyclooxygenase-2 (COX-2) inhibitors, endowed with fine tuned selectivity and high potency, in the past years we have identified novel classes of ether, ester and acid molecules characterized by the 1,5-diarylpyrrole scaffold as potentially powerful anti-inflammatory molecules (12-66). All compounds proved to exert an in vitro inhibition profile as good as that shown by reference compounds. Compounds bearing a p-methylsulfonylphenyl substituent at C5 displayed the best issues. In particular, ester derivatives proved to perform the best in vitro profile in terms of selectivity and activity toward COX-2. The cell-based assay data showed that an increase of hindrance at the C3 side chain of compounds could translate to activity enhancement. The human whole blood (HWB) test let to highlight that submitted compounds displayed 5-10 fold higher selectivity for COX-2 vs COX-1 which should translate clinically to an acceptable gastrointestinal safety and mitigate the cardiovascular effects highlighted by highly selective COX-2 inhibitors. Finally, to assess in vivo anti-inflammatory and analgesic activity three different tests (rat paw pressure, rat paw oedema and abdominal constriction) were performed. Results showed good in vivo anti-inflammatory and analgesic activities. The issues gained with these classes of compounds represent, nowadays, a potent stimulus for a further enlargement of the NSAIDs family. In this review we describe the results obtained by our research group on this topic.


Assuntos
Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Pirróis/química , Pirróis/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Analgésicos/uso terapêutico , Animais , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios não Esteroides/uso terapêutico , Ciclo-Oxigenase 1/metabolismo , Ciclo-Oxigenase 2/metabolismo , Inibidores de Ciclo-Oxigenase/química , Inibidores de Ciclo-Oxigenase/farmacologia , Inibidores de Ciclo-Oxigenase/uso terapêutico , Humanos , Pirróis/uso terapêutico , Relação Estrutura-Atividade
7.
J Photochem Photobiol B ; 56(1): 61-7, 2000 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11073317

RESUMO

The 365-nm irradiation of 4.6 microM (approximately equal to 1.1 mg/ml) catalase solutions in pH 7.4 phosphate buffer induces spectral modifications. Difference spectra show maxima at 434, 555, 584 nm at the beginning of the irradiation, then a final spectrum with a maximum at 568 nm and a shoulder at 530 nm is observed. These results suggest the formation of compound III (oxyferrous catalase) and compound II, respectively. In deaerated 0.1 M, pH 8.7 borate buffer, the ferrous catalase is characterized by maxima at 563 and 594 nm. Hydrogen donors such as ethyl alcohol, formate and p-cresol inhibit, but citrate ions enhance the formation of these intermediates. A mechanism involving Fe(III) reduction according to an internal electron transfer is proposed.


Assuntos
Catalase/efeitos da radiação , Raios Ultravioleta , Animais , Catalase/química , Bovinos , Relação Dose-Resposta à Radiação , Concentração de Íons de Hidrogênio , Cinética , Fígado/enzimologia , Fotólise , Soluções
8.
J Photochem Photobiol B ; 54(1): 43-54, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-10739142

RESUMO

Iron and/or ferritin accumulation are known to occur under pathological conditions in many inflammatory skin diseases or in human skin chronically exposed to UV light. Under such conditions, ferritin is believed to play an effective protective role in accommodating and 'deactivating' excess 'free' iron produced by the inflammatory process or the UV illumination. The present study compares the relationship between ferritin over-expression and effects of an oxidative stress induced chemically by tert-butyl hydroperoxide or photochemically by UV-A radiation. As shown by immunoassay, cultured MRC 5 and HS 68 fibroblasts treated for at least one day with transferrin or overnight with non-toxic concentrations of the ferric nitrilotriacetate complex express up to 10 times more ferritin than untreated cells, whereas a five-fold increase is obtained with NCTC 2544 keratinocytes. In all cases a parallel increase in soluble cellular iron is measured by inductive plasma emission spectroscopy. The superoxide dismutase and catalase activities and total glutathione levels are not modified by the iron treatment, whereas a transient increase in the Se-dependent glutathione peroxidase activity of keratinocytes is observed after a short incubation with the iron complex. In keratinocytes and fibroblasts, ferritin over-expression after iron treatment markedly inhibits lipid peroxidation but, paradoxically, not the mortality induced by tert-butyl hydroperoxide. In contrast, this excess ferritin does not protect cells from both the peroxidation and mortality induced by moderate doses (30 J/cm2) of UV-A radiation. As a consequence, protection against oxidative damage by excess ferritin synthesis clearly depends on the nature of the oxidative stress on cell targets and it seems to be of lesser importance in the case of photochemically induced oxidation.


Assuntos
Compostos Férricos/farmacologia , Ferritinas/metabolismo , Fibroblastos/metabolismo , Queratinócitos/metabolismo , Ácido Nitrilotriacético/análogos & derivados , Estresse Oxidativo , Raios Ultravioleta , terc-Butil Hidroperóxido/farmacologia , Catalase/metabolismo , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Fibroblastos/efeitos dos fármacos , Fibroblastos/efeitos da radiação , Glutationa/metabolismo , Glutationa Peroxidase/metabolismo , Humanos , Ferro/metabolismo , Queratinócitos/efeitos dos fármacos , Queratinócitos/efeitos da radiação , Pulmão , Ácido Nitrilotriacético/farmacologia , Superóxido Dismutase/metabolismo , Substâncias Reativas com Ácido Tiobarbitúrico/análise
9.
Photochem Photobiol ; 72(6): 746-52, 2000 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11140262

RESUMO

The ultraviolet-A (UVA) component of sunlight produces in cutaneous cells a highly toxic oxidative stress mediated by redox cycling reactions of Fe ions. A tight regulation of cell iron uptake and storage by iron regulatory proteins (IRP) of keratinocytes and fibroblasts avoids these damaging reactions. We report here that about 40 J/cm2 of UVA are required to inactivate half of the binding capacity of apo-IRP-1 to iron responsive elements (IRE) of RNA whereas 15 J/cm2 already inhibit half of the holo-IRP-1 aconitase activity. No increase in the holo-IRP-1 activity is observed during the apo-IRP-1 photoinactivation suggesting that UVA does not trigger a shift between these two forms. As opposed to holo-IRP-1, which contains a 4Fe-4S cluster, apo-IRP-1 has no UVA chromophore. Thus it should be inactivated indirectly by reactive oxygen species generated by the UVA-induced endogenous photo-oxidative stress. The apo-IRP-1 photoinactivation is weakly prevented by the lipophilic oxyradical scavenger vitamin E but not by the hydrophilic azide anion, a singlet oxygen quencher or by diethyldithiocarbamate, a superoxide dismutase inhibitor. However, full protection against photoinactivation of the apo form is observed after incubation with N-acetylcysteine but the latter only partially protects the aconitase function of the holo-IRP-1 from photoinactivation. The marked difference in the kinetics of photoinactivation of the apo and holo forms, the light dose-independent effect of the sulfhydril group reagent, 2-mercaptoethanol and the partial protection brought by the ferric ion complexing agent desferrioxamine suggest that the photochemistry of the 4Fe-4S cluster of the holo form plays little, if any, role in the photoinactivation of the apo-IRP-1/IRE interaction. It is concluded that the apo/holo equilibrium is irreversibly destroyed by UVA irradiation.


Assuntos
Aconitato Hidratase/metabolismo , Proteínas Ferro-Enxofre/metabolismo , Proteínas de Ligação a RNA/metabolismo , Pele/efeitos da radiação , Raios Ultravioleta , Células Cultivadas , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Fibroblastos/efeitos da radiação , Humanos , Proteínas Reguladoras de Ferro , Queratinócitos/enzimologia , Queratinócitos/metabolismo , Queratinócitos/efeitos da radiação , Pele/citologia , Pele/enzimologia , Pele/metabolismo
10.
Phys Med Biol ; 44(3): N31-8, 1999 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-10211813

RESUMO

The lack of well established dosimetry protocols for HDR sources is a point of great concern regarding the uniformity of procedures within a particular country and worldwide. The main objective of this paper is to report the results from ten institutions of an intercomparison of calibration procedures for 192Ir HDR sources currently in use in Brazil. The treatment irradiator of one institution was calibrated by a reference system and used by all participants with their own measuring electrometers and ionization chambers under the same experimental conditions. Two methods were used: the calibration jig and the well-type ionization chamber. Each participant was allowed to use their own method and formalism. The results of this exercise were very positive since this was the first time in Brazil that a group of users gathered to share their experience and openly discuss the physical concepts behind the calibration procedures. The results were all within +/-3.0%, except one case where -4.6% was observed and later identified as a problem with the Nk value for x-rays. Though the magnitude of the deviations found was generally acceptable considering the diversity of formalisms currently in use, a proposal is now being prepared to be adopted as a national protocol. The identification of the institutions was left out for the sake of confidentiality.


Assuntos
Radioisótopos de Irídio/análise , Radiometria , Braquiterapia , Brasil , Calibragem , Raios gama
11.
J Pharm Pharmacol ; 50(10): 1147-53, 1998 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9821662

RESUMO

The compound CI-1007 (R-(+)-1,2,3,6-tetrahydro-4-phenyl-1 [(3-phenyl-3-cyclohexen-1-yl)methyl]pyridine maleate) has been identified as a partial dopamine agonist and putative antipsychotic in in-vitro and in-vivo neurochemical, neurophysiological and behavioural tests. By use of microdialysis in conjunction with high-performance liquid chromatography (HPLC) with electrochemical detection, the effects of the drug on brain dopamine release, previously observed in anaesthetized animals, were shown to occur in awake animals also. Detection of peripherally administered CI-1007 in the brain, i.e. evidence of the drug's ability to penetrate the blood-brain barrier, was achieved by use of in-vivo brain microdialysis in awake, freely moving rats and capillary HPLC in combination with tandem mass spectrometry (HPLC/MS/MS). Intravenous administration of CI-1007 (40 mg kg-1) significantly inhibits dopamine release in the nucleus accumbens, a region associated with dopamine hyperactivity in schizophrenia, while having a non-significant impact on the striatal dopamine neurotransmission which is critical to regular motor function. The differential neurochemical profile of the drug indicates its potential usefulness in treating positive disease symptoms and implies that its extrapyramidal side effects are lower than those of typical antipsychotics.


Assuntos
1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/análogos & derivados , Antipsicóticos/farmacologia , Agonistas de Dopamina/farmacologia , Dopamina/metabolismo , Núcleo Accumbens/efeitos dos fármacos , Córtex Visual/efeitos dos fármacos , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacocinética , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/farmacologia , Animais , Antipsicóticos/farmacocinética , Barreira Hematoencefálica , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cromatografia , Agonistas de Dopamina/farmacocinética , Masculino , Espectrometria de Massas , Microdiálise , Núcleo Accumbens/metabolismo , Ratos , Ratos Sprague-Dawley , Córtex Visual/metabolismo
12.
Photochem Photobiol ; 68(3): 309-13, 1998 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9747587

RESUMO

The aconitase activity of the cytoplasmic iron regulatory protein-1 of NCTC 2544 keratinocytes is effectively inhibited by physiological doses of UVA. The time course of the photoinactivation is biphasic. A fast step is first observed corresponding to about 50% inactivation after exposure to 5 J/cm2 of UVA followed by a much slower photoinactivation at higher doses. The water-soluble antioxidant N-acetylcysteine only partially inhibits the photoinduced inactivation of the cytoplasmic aconitase function, whereas the lipophilic vitamin E, the iron chelator, desferrioxamine and the superoxide dismutase inhibitor, diethyldithiocarbamate do not protect at all. As a consequence, reactive oxygen species such as O2-., H2O2 and lipid peroxides and hydroperoxides seem to play a rather minor role in the inactivation induced by the UVA photooxidative stress although an oxidative stress produced by O2-. and H2O2 is known to inhibit reversibly and effectively cytoplasmic aconitase activity in mammalian cells.


Assuntos
Aconitato Hidratase/efeitos da radiação , Proteínas Ferro-Enxofre/efeitos da radiação , Queratinócitos/metabolismo , Proteínas de Ligação a RNA/efeitos da radiação , Raios Ultravioleta , Aconitato Hidratase/antagonistas & inibidores , Animais , Linhagem Celular , Humanos , Proteínas Reguladoras de Ferro , Proteínas Ferro-Enxofre/antagonistas & inibidores , Mamíferos , Proteínas de Ligação a RNA/antagonistas & inibidores , Pele
13.
Bioorg Med Chem Lett ; 8(20): 2907-12, 1998 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-9873646

RESUMO

Kynurenine 3-hydroxylase (KYN 3-OHase) is a key enzyme in the kynurenine pathway of tryptophan degradation and its inhibition may be an effective mechanism for counteracting neuronal excitotoxic damage. We present here a new class of inhibitors derived from a structure-activity relationship (SAR) study of the benzoylalanine side-chain of 1. 2-hydroxy-4-(3,4-dichlorophenyl)-4-oxobutanoic acid (8) and 2-benzyl-4-(3,4-dichlorophenyl)-4-oxo-butanoic acid (10) emerged as the most interesting derivatives. Enantiospecific synthesis for both enantiomers of 8 and diastereomeric salt resolution for those of 10 were successfully applied.


Assuntos
Inibidores Enzimáticos/química , Oxigenases de Função Mista/antagonistas & inibidores , Fenilbutiratos/química , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Inibidores Enzimáticos/farmacologia , Humanos , Concentração Inibidora 50 , Quinurenina 3-Mono-Oxigenase , Fígado/efeitos dos fármacos , Fígado/enzimologia , Fenilbutiratos/farmacologia , Ratos , Relação Estrutura-Atividade , Triptofano/metabolismo
14.
J Biopharm Stat ; 7(3): 453-65, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9252837

RESUMO

Electrospray ionization (ES) is a novel method used in mass spectrometry (MS) for producing gas-phase ions from substances in solutions. Common practices for molecular mass estimation from ES spectra summarize the spectrum as a single peak giving no estimate of uncertainty or treat each peak as an independent molecular mass measurement. ES-MS data analysis showed that each peak in an ES spectrum does not always provide an independent measure of molecular mass. Underestimation of measurement uncertainty is a possible result. An elementary time series method, the Yule-Walker equations, was applied to molecular mass estimation from ES data.


Assuntos
Físico-Química/métodos , Espectrometria de Massas/métodos , Estatística como Assunto/métodos , Animais , Cavalos , Modelos Lineares , Peso Molecular , Miocárdio/química , Mioglobina/química
15.
Redox Rep ; 3(1): 49-55, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27414771

RESUMO

Photoinactivation of catalase is found to be similar in solution and in human normal skin fibroblasts exposed to ultraviolet B, ultraviolet A and near visible light, and the kinetics of such photoinactivation obey first order processes. The action spectrum, measured for the first time in cells, suggests that catalase photoinactivation in solution and in cells proceeds via similar routes. In both systems, no protective effect was observed with diethyldithiocarbamate, a superoxide dismutase inhibitor, with desferrioxamine, an iron chelator which impedes the production of hydroxyl radical via the Fenton reaction, and with vitamin E which scavenges peroxyl radical to protect against membrane peroxidative process. While the absence of protection by these inhibitors may be anticipated for the photoinactivation of catalase in solution, the lack of effect in cells suggests that reactive oxygen species produced by endogenous photosensitization are not responsible for the enzyme inactivation. Moreover, the already established protective effect of ethanol in solution is also observed in cells, supporting the view that photoinactivation in solution and in cells is due to the same primary events.

18.
J Biol Chem ; 270(8): 3518-26, 1995 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-7876086

RESUMO

We describe the purification and first biochemical characterization of an enzymatic activity in venom from the marine snail Conus magus. This enzyme, named conodipine-M, is a novel phospholipase A2 with a molecular mass of 13.6 kDa and is comprised of two polypeptide chains linked by one or more disulfide bonds. The amino acid sequence of conodipine-M shows little if any homology to other previously sequenced phospholipase A2 enzymes (PLA2s). Conodipine-M thus represents a new group of PLA2s. This is remarkable, since conodipine-M displays a number of properties that are similar to those of previously characterized 14-kDa PLA2s. The enzyme shows little, if any, phospholipase A1, diacyglycerol lipase, triacylglycerol lipase, or lysophospholipase activities. Conodipine-M hydrolyzes the sn-2 ester of various preparations of phospholipid only in the presence of calcium and with specific activities that are comparable to those of well known 14-kDa snake venom and pancreatic PLA2s. The Conus enzyme binds tightly to vesicles of the negatively charged phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphomethanol and catalyzes the hydrolysis of this substrate in a processive fashion. Conodipine-M does not significantly discriminate against phospholipids with unsaturated versus saturated fatty acids at the sn-2 position or with different polar head groups. Linoleoyl amide and a phospholipid analog containing an alkylphosphono group at the sn-2 position are potent inhibitors of conodipine-M. We suggest that the functional resemblance of conodipine-M to other PLA2s might be explained by the utilization of similar catalytic residues.


Assuntos
Venenos de Moluscos/enzimologia , Fosfolipases A/isolamento & purificação , Caramujos/enzimologia , Sequência de Aminoácidos , Animais , Cálcio/metabolismo , Dados de Sequência Molecular , Fosfolipases A/antagonistas & inibidores , Fosfolipases A/química , Fosfolipases A/metabolismo , Fosfolipases A1 , Fosfolipases A2 , Fosfolipases A2 Secretórias , Homologia de Sequência de Aminoácidos , Especificidade por Substrato
19.
Pharm Res ; 11(12): 1712-20, 1994 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-7899233

RESUMO

Human epidermal growth factor 1-48 (hEGF 1-48, Des(49-53)hEGF) is a single chain polypeptide (48 amino acids; 3 disulfide bonds; 5445 Da) possessing a broad spectrum of biologic activity including the stimulation of cell proliferation and tissue growth. In this study, three primary aqueous degradation products of hEGF 1-48 were isolated using isocratic, reverse phase/ion-pair HPLC. The degradation products were characterized using amino acid sequencing, electrospray ionization mass spectrometry, isoelectric focusing, and degradation kinetics. Results indicate that hEGF 1-48 degrades via oxidation (Met21), deamidation (Asn1), and succinimide formation (Asp11). The relative contribution of each degradation pathway to the overall stability of hEGF 1-48 changes as a function of solution pH and storage condition. Succinimide formation at Asp11 is favored at pH < 6 in which aspartic acid is present mostly in its protonated form. Deamidation of Asn1 is favored at pH > 6. The relative contribution of Met21 oxidation is increased with decreasing temperature, storage as a frozen solution (-20 degrees C), and exposure to fluorescent light.


Assuntos
Fator de Crescimento Epidérmico/química , Sequência de Aminoácidos , Estabilidade de Medicamentos , Fluorescência , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Temperatura
20.
J Med Chem ; 37(21): 3588-604, 1994 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-7932586

RESUMO

A new class of compounds combining thromboxane-A2 (TxA2) receptor antagonism and thromboxane synthase inhibition is described. A first series of (E)- and (Z)-[[[2-(1H-imidazol-1-yl)ethylidene]amino]oxy]pentanoic acids showed relevant thromboxane synthase inhibition associated with weak TxA2 receptor antagonism, while a series of (+/-)-(E)-[[[2-(1H-imidazol-1-yl)-3-phenylpropylidene]amino]oxy] pentanoic acids, structurally derived from the former, showed potent and well-balanced dual activity. Structural requirements for significant single and dual activity are discussed. Two close congeners of the latter series, (+/-)-(E)-5-[[[1-cyclohexyl-2-(1H-imidazol-1-yl)-3- phenylpropylidene]amino]oxy]pentanoic acid 23c and its p-fluorophenyl analog 23m, inhibited TxB2 production in vitro, in rat whole blood during clotting, with IC50 of 0.06 and 0.37 microM and antagonized the binding of [3H]SQ 29548 to washed human platelets, with IC50 of 0.08 and 0.02 microM, respectively. These two compounds were selected for further pharmacological evaluation and were shown to antagonize U46619-induced platelet aggregation in human platelet rich plasma with IC50 of 0.30 and 0.44 microM, respectively. They were both orally available, and in particular 23m caused a long lasting ex vivo TxA2 synthase inhibition in the fed rat. The levorotatory enantiomer of 23c, stereospecifically synthesized as a model compound, was found to be more potent than racemic 23c with regard to TxA2 receptor antagonism (IC50 = 0.04 microM) and equivalent to the latter with regard to TxA2 synthase inhibition. A molecular modeling study concerning the levorotatory enantiomer of 23c (S), TxA2, and representative TxA2 antagonists of different classes led to the definition of a putative pharmacophoric model for the TxA2 receptor ligands.


Assuntos
Imidazóis/síntese química , Ácidos Pentanoicos/síntese química , Receptores de Tromboxanos/antagonistas & inibidores , Tromboxano-A Sintase/antagonistas & inibidores , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico , Animais , Ligação Competitiva , Plaquetas/efeitos dos fármacos , Plaquetas/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes , Simulação por Computador , Cães , Ácidos Graxos Insaturados , Fibrinolíticos , Humanos , Hidrazinas/sangue , Imidazóis/química , Imidazóis/farmacologia , Masculino , Modelos Moleculares , Estrutura Molecular , Ácidos Pentanoicos/química , Ácidos Pentanoicos/farmacologia , Agregação Plaquetária/efeitos dos fármacos , Endoperóxidos Sintéticos de Prostaglandinas/farmacologia , Ratos , Ratos Sprague-Dawley , Estereoisomerismo , Tromboxano A2/análogos & derivados , Tromboxano A2/farmacologia , Tromboxano B2/antagonistas & inibidores
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