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1.
Mol Genet Metab ; 132(2): 94-99, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32713717

RESUMEN

Respiratory outcomes in Mucopolysaccharidosis Type I (MPS I), have mainly focused on upper airway obstruction, with the evolution of the restrictive lung disease being poorly documented. We report the long-term pulmonary function outcomes and examine the potential factors affecting these in 2 cohorts of MPS I patients, those who have undergone Haematopoietic Stem Cell Transplantation (HSCT) and those treated with Enzyme Replacement Therapy (ERT). The results were stratified using the American Thoracic Society (ATS) guidelines. 66 patients, capable of adequately performing testing, were identified by a retrospective case note review, 46 transplanted (45 Hurler, 1 Non-Hurler) and 20 having ERT (17 Non-Hurler and 3 Hurler diagnosed too late for HSCT). 5 patients died; 4 in the ERT group including the 3 Hurler patients. Overall 14% of patients required respiratory support (non-invasive ventilation (NIV) or supplemental oxygen)) at the end of follow up. Median length of follow-up was 12.2 (range = 4.9-32) years post HSCT and 14.34 (range = 3.89-20.4) years on ERT. All patients had restrictive lung disease. Cobb angle and male sex were significantly associated with more severe outcomes in the HSCT cohort, with 49% having severe to very severe disease. In the 17 Non-Hurler ERT treated patients there was no variable predictive of severity of disease with 59% having severe to very severe disease. During the course of follow up 67% of the HSCT cohort had no change or improved pulmonary function as did 52% of the ERT patients. However, direct comparison between therapeutic modalities was not possible. This initial evidence would suggest that a degree of restrictive lung disease is present in all treated paediatrically diagnosed MPS I and is still a significant cause of morbidity, though further stratification incorporating diffusing capacity for carbon monoxide (DLCO) is needed.


Asunto(s)
Obstrucción de las Vías Aéreas/terapia , Enfermedades Pulmonares Obstructivas/terapia , Mucopolisacaridosis I/terapia , Adolescente , Adulto , Edad de Inicio , Anciano , Anciano de 80 o más Años , Obstrucción de las Vías Aéreas/complicaciones , Obstrucción de las Vías Aéreas/epidemiología , Obstrucción de las Vías Aéreas/patología , Monóxido de Carbono/metabolismo , Niño , Preescolar , Terapia de Reemplazo Enzimático , Femenino , Trasplante de Células Madre Hematopoyéticas/efectos adversos , Humanos , Lactante , Enfermedades Pulmonares Obstructivas/complicaciones , Enfermedades Pulmonares Obstructivas/epidemiología , Enfermedades Pulmonares Obstructivas/patología , Masculino , Persona de Mediana Edad , Mucopolisacaridosis I/complicaciones , Mucopolisacaridosis I/epidemiología , Mucopolisacaridosis I/patología , Adulto Joven
2.
Pharmazie ; 75(11): 611-617, 2020 11 01.
Artículo en Inglés | MEDLINE | ID: mdl-33239140

RESUMEN

In 1719, Antonio Menzani di Cuna from the Saint Savior monastery published an alcoholic extract formula made from plant and herb resins under the name Jerusalem Balsam. The Balsam gained high popularity due to its remedial benefits. At the end of the 19 th century, Jerusalem Balsam produced by the hermit Johannes Treutler was found to be particularly popular. We analysed a sample of a valuable find coming from the last decade of the 19 th century, making it probably the oldest surviving Jerusalem Balsam in the world. The purpose of this work was to investigate the composition of the historical sample and to try to determine the origin of its components. This was achieved by comparing the profile of volatile compounds extracted from the balsam using HS-SPME technique with the profile characteristic for plant resins as classic ingredients of the Johannes Treutler formula. The use of two chromatographic columns of different polarity, as well as the transformation of the polar components of the sample into TMS derivatives, allowed to obtain new information on the historical composition of the Balsam. Also, it can be stated with high probability that plant resins were indeed used in the production of the Balsam as referred to in the original recipe of Johannes Treutler. We also discuss challenges in determining the original composition of the Balsam.


Asunto(s)
Bálsamos/historia , Resinas de Plantas/historia , Bálsamos/química , Química Farmacéutica , Historia del Siglo XIX , Humanos , Israel , Resinas de Plantas/química , Microextracción en Fase Sólida
3.
Nature ; 484(7392): 75-7, 2012 Apr 04.
Artículo en Inglés | MEDLINE | ID: mdl-22481359

RESUMEN

RR Lyrae pulsating stars have been extensively used as tracers of old stellar populations for the purpose of determining the ages of galaxies, and as tools to measure distances to nearby galaxies. There was accordingly considerable interest when the RR Lyrae star OGLE-BLG-RRLYR-02792 (referred to here as RRLYR-02792) was found to be a member of an eclipsing binary system, because the mass of the pulsator (hitherto constrained only by models) could be unambiguously determined. Here we report that RRLYR-02792 has a mass of 0.26 solar masses M[symbol see text] and therefore cannot be a classical RR Lyrae star. Using models, we find that its properties are best explained by the evolution of a close binary system that started with M[symbol see text] and 0.8M[symbol see text]stars orbiting each other with an initial period of 2.9 days. Mass exchange over 5.4 billion years produced the observed system, which is now in a very short-lived phase where the physical properties of the pulsator happen to place it in the same instability strip of the Hertzsprung-Russell diagram as that occupied by RR Lyrae stars. We estimate that only 0.2 per cent of RR Lyrae stars may be contaminated by systems similar to this one, which implies that distances measured with RR Lyrae stars should not be significantly affected by these binary interlopers.

4.
Opt Lett ; 39(12): 3571-4, 2014 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-24978539

RESUMEN

In this Letter we present, for the first time to our knowledge, the results of fiber Bragg grating (FBG) inscription in a novel microstructured multicore fiber characterized by seven single-mode isolated cores. A clear Bragg reflection peak can be observed in all of the 7 cores after one inscription process with a KrF nanosecond laser in a Talbot interferometer set up. We furthermore perform a numerical analysis of the effective refractive indices of the particular modes and compare it with the FBG inscription results. An experimental analysis of the strain and temperature sensitivities of all of the Bragg peaks is also included.

5.
Ann Oncol ; 21(4): 787-794, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-19833821

RESUMEN

BACKGROUND: To evaluate the clinical and radiological effectiveness of [DOTA(0), D-Phe(1), Tyr(3)]-octreotate (DOTATATE) Y-90 in patients with extensive progressive gastroenteropancreatic neuroendocrine carcinomas (GEP-NETs). MATERIALS AND METHODS: Sixty patients with histologically proven GEP-NETs were treated with DOTATATE Y-90. Clinical responses were assessed 6 weeks after completing therapy and then after each of the 3- to 6-month intervals. The radiological response was classified according to RECIST criteria. RESULTS: At 6 months after final treatment, radiological partial response (PR; at least a 30% decrease in the sum of the longest diameter of target lesions) was observed in 13 patients (23%), and the remaining patients had stable disease (SD; less than 30% decrease in the sum of the longest diameter of target lesions or less than 20% increase in the sum of the longest diameter of target lesions) (77%). Clinical PR at 6 months was in 43 patients (72%), nine patients had SD and progressive disease (PD) was noted in eight patients. Median progression-free survival (PFS) was 17 months, while the median overall survival (OS) was 22 months. In eight patients with early PD, the PFS was 4.5 and OS 9.5 months, while in those with SD or PR, PFS and OS were 19.5 and 23.5 months, respectively. After 12 months of follow-up, five patients had World Health Organization (WHO) grade 2 or 3 renal toxicity. Haematological toxicity (WHO grade 3 and 4) was noted during therapy in 10% of patients and persisted in 5%. CONCLUSIONS: DOTATATE Y-90 therapy is effective and relatively safe in patients with GEP-NET. Standard doses of DOTATATE Y-90 result in a relatively low risk of myelotoxicity. However, due to ongoing risk of renal toxicity, careful monitoring of the kidney is recommended.


Asunto(s)
Carcinoma Neuroendocrino/diagnóstico por imagen , Neoplasias Gastrointestinales/diagnóstico por imagen , Octreótido/análogos & derivados , Compuestos Organometálicos/uso terapéutico , Neoplasias Pancreáticas/diagnóstico por imagen , Radioisótopos de Itrio/uso terapéutico , Adulto , Anciano , Antineoplásicos/efectos adversos , Antineoplásicos/uso terapéutico , Carcinoma Neuroendocrino/patología , Progresión de la Enfermedad , Femenino , Neoplasias Gastrointestinales/patología , Humanos , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Octreótido/administración & dosificación , Octreótido/efectos adversos , Octreótido/uso terapéutico , Neoplasias Pancreáticas/patología , Cintigrafía , Resultado del Tratamiento , Adulto Joven , Radioisótopos de Itrio/efectos adversos
6.
Mol Genet Metab Rep ; 21: 100508, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31687335

RESUMEN

Mucopolysaccharidoses (MPS) are rare disorders associated with enzyme deficiencies, resulting in glycosaminoglycan (GAG) accumulation in multiple organ systems. As patients increasingly survive to adulthood, the need for a smooth transition into adult care is essential. Using case studies, we outline strategies and highlight the challenges of transition, illustrating practical solutions that may be used to optimise the transition process for patients with MPS disorders. Seven MPS case studies were provided by four European inherited metabolic disease centres; six of these patients transferred to an adult care setting and the final patient remained under paediatric care. Of the patients who transferred, age at the start of transition ranged between 14 and 18 years (age at transfer ranged from 16 to 19 years). While there were some shared features of transition strategies, they varied in duration, the healthcare professionals involved and the management of adult patients with MPS. Challenges included complex symptoms, patients' unwillingness to attend appointments with unfamiliar team members and attachment to paediatricians. Challenges were resolved by starting transition at an early age, educating patients and families, and providing regular communication with and reassurance to the patient and family. Sufficient time should be provided to allow patients to understand their responsibilities in the adult care setting while feeling assured of continued support from healthcare professionals. The involvement of a coordinated multidisciplinary team with expertise in MPS is also key. Overall, transition strategies must be comprehensive and individualised to patients' needs.

7.
Orphanet J Rare Dis ; 14(1): 86, 2019 04 27.
Artículo en Inglés | MEDLINE | ID: mdl-31029175

RESUMEN

BACKGROUND: Classic galactosemia is a rare inborn error of carbohydrate metabolism, caused by a severe deficiency of the enzyme galactose-1-phosphate uridylyltransferase (GALT). A galactose-restricted diet has proven to be very effective to treat the neonatal life-threatening manifestations and has been the cornerstone of treatment for this severe disease. However, burdensome complications occur despite a lifelong diet. For rare diseases, a patient disease specific registry is fundamental to monitor the lifespan pathology and to evaluate the safety and efficacy of potential therapies. In 2014, the international Galactosemias Network (GalNet) developed a web-based patient registry for this disease, the GalNet Registry. The aim was to delineate the natural history of classic galactosemia based on a large dataset of patients. METHODS: Observational data derived from 15 countries and 32 centers including 509 patients were acquired between December 2014 and July 2018. RESULTS: Most affected patients experienced neonatal manifestations (79.8%) and despite following a diet developed brain impairments (85.0%), primary ovarian insufficiency (79.7%) and a diminished bone mineral density (26.5%). Newborn screening, age at onset of dietary treatment, strictness of the galactose-restricted diet, p.Gln188Arg mutation and GALT enzyme activity influenced the clinical picture. Detection by newborn screening and commencement of diet in the first week of life were associated with a more favorable outcome. A homozygous p.Gln188Arg mutation, GALT enzyme activity of ≤ 1% and strict galactose restriction were associated with a less favorable outcome. CONCLUSION: This study describes the natural history of classic galactosemia based on the hitherto largest data set.


Asunto(s)
Galactosemias/patología , UTP-Hexosa-1-Fosfato Uridililtransferasa/genética , Adolescente , Adulto , Estudios de Cohortes , Femenino , Galactosemias/genética , Homocigoto , Humanos , Recién Nacido , Masculino , Mutación/genética , Tamizaje Neonatal , Sistema de Registros , Estudios Retrospectivos , Adulto Joven
8.
Clin Exp Rheumatol ; 26(4): 527-33, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-18799080

RESUMEN

OBJECTIVES: To evaluate serum levels of fractalkine (FKN), a mediator of leukocyte transmigration, C-reactive protein (CRP) and expression of integrins CD11a and CD49d on peripheral blood lymphocytes in systemic sclerosis (SSc) and to investigate whether they are modulated by intravenous prostaglandin E1 (PGE1). METHODS: Serum levels of fractalkine and C-reactive protein and expression of CD11a and CD49d on peripheral blood lymphocytes were assessed in 50 SSc patients and in 18 healthy controls. In 25 SSc patients studied parameters were evaluated also after 3 consecutive daily PGE1 infusions (20 microg-40 microg-60 microg) and after 4 weeks. RESULTS: In SSc fractalkine basal level was significantly higher than in controls (9.04+/-1.79 ng/ml vs. 1.17+/-0.1 ng/ml; p<0.0001) and decreased significantly after PGE1 (5.16+/-1.27 ng/ml, p<0.05). After four weeks fractalkine level was still significantly lower than baseline 7.70+/-2.19 ng/ml (p<0.05). Basal percentage of CD11a (+) nor CD49d (+) lymphocytes in SSc (82.38+/-1.60%, 70.74+/-1.68%, respectively) did not differ from controls (85.73+/-2.04%, 75.62+/-2.48%; respectively, p>0.05). PGE1 treatment resulted in decrease of both CD11a (+) (67.72+/-3.34%, p<0.0001) and CD49d (+) lymphocytes (65.32+/-1.62%, p<0.0001). After 4 weeks the percentage of CD11a (+) and CD49d (+) lymphocytes remained significantly lower than at baseline (77.80+/-2.47% and 65.32+/-1.62%, respectively, both p<0.001). In SSc CRP basal level was significantly higher than in controls (4.70+/-2.01 mg/dl vs. 1.40+/-1.79 mg/dl, p<0.005) and reduced significantly after PGE1 (3.39+/-2.06 mg/dl, p<0.05). After 4 weeks, CRP level (4.38+/-2.19 ng/ml) was significantly lower than baseline (p<0.05). CONCLUSION: Fractalkine may play an important role in the pathogenesis of vascular dysfunction in systemic sclerosis. Prostaglandin E1 down-regulates serum fractalkine level, as well as CD11a and CD49d expression on peripheral blood lymphocytes, which suggests additional mechanisms in which this vasodilatatory agent exerts its efficacy in systemic sclerosis.


Asunto(s)
Alprostadil/administración & dosificación , Quimiocina CX3CL1/sangre , Esclerodermia Difusa/tratamiento farmacológico , Esclerodermia Limitada/tratamiento farmacológico , Vasodilatadores/administración & dosificación , Adulto , Proteína C-Reactiva/análisis , Proteína C-Reactiva/efectos de los fármacos , Antígeno CD11a/efectos de los fármacos , Antígeno CD11a/metabolismo , Estudios de Casos y Controles , Quimiocina CX3CL1/efectos de los fármacos , Regulación hacia Abajo , Femenino , Humanos , Infusiones Intravenosas , Integrina alfa4/efectos de los fármacos , Integrina alfa4/metabolismo , Linfocitos/efectos de los fármacos , Linfocitos/metabolismo , Masculino , Persona de Mediana Edad , Esclerodermia Difusa/sangre , Esclerodermia Limitada/sangre
9.
Neurosci Lett ; 404(1-2): 56-60, 2006 Aug 14.
Artículo en Inglés | MEDLINE | ID: mdl-16787708

RESUMEN

Elevated levels of homocysteine have been observed in Parkinson's disease (PD) patients treated with levodopa. However, it is not studied if duration of PD or PD per se is associated with hyperhomocysteinemia. In the present study, the levels of homocysteine in 99 levodopa-treated PD patients, 15 untreated PD patients and 100 controls were examined. We focused on the influence of levodopa dose, duration of therapy and disease as well as genetic (C677T methylenetetrahydrofolate reductase (MTHFR) polymorphism) and environmental factors. We found that levodopa-treated PD patients had elevated homocysteine plasma levels as compared to controls (p < 0.05), but the levels did not depend on levodopa doses. Another factor influencing homocysteine level was the duration of PD (p < 0.001). The frequency of allele C677T of MTHFR gene did not differ between PD and controls. In conclusion, hyperhomocysteinemia is associated with the duration of PD and levodopa treatment and possibly also with PD per se.


Asunto(s)
Hiperhomocisteinemia/etiología , Metilenotetrahidrofolato Reductasa (NADPH2)/genética , Enfermedad de Parkinson/sangre , Enfermedad de Parkinson/genética , Polimorfismo de Nucleótido Simple , Adulto , Anciano , Anciano de 80 o más Años , Ácido Fólico , Homocisteína/sangre , Humanos , Levodopa/uso terapéutico , Persona de Mediana Edad , Enfermedad de Parkinson/tratamiento farmacológico , Valores de Referencia , Vitamina B 12/sangre
11.
Folia Neuropathol ; 54(3): 197-211, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27764513

RESUMEN

Pilocytic astrocytomas (PAs) are the most frequent primary astroglial tumours affecting children and adolescents. They occur sporadically or in association with a genetically determined syndrome - neurofibromatosis type 1. Classic PA usually manifests as a well-circumscribed, often cystic, slowly growing tumour, which corresponds to WHO grade I. The majority of pilocytic tumours arise along the neuraxis, predominantly in the cerebellum. They are associated with favourable long-term outcome or spontaneous regression, even after incomplete resection. However, the behaviour and prognosis might also be related to tumour histology and location. Pilomyxoid astrocytoma (PMA) represents a variant of classical PA with more invasive growth and increased risk of recurrences and dissemination. Typically, PAs exhibit distinct histology with biphasic architecture of loose, microcystic and compact, fibrillary areas. However, some tumours arise in an uncommon location and display heterogeneous histopathological appearance. The morphological pattern of PA can mimic some other glial neoplasms, including oligodendroglioma, pleomorphic xanthoastrocytoma, ependymoma or diffuse astrocytoma. Not infrequently, the advanced degenerative changes, including vascular fibrosis, and recent and old haemorrhages, may mimic vascular pathology. Sometimes, the neoplastic piloid tissue can resemble reactive gliosis, related to long-standing non neoplastic lesions. Not infrequently, PA exhibits histological features typical for anaplasia, including necrosis, mitoses and glomeruloid vascular proliferation that can suggest a diffuse high-grade glioma. However, even those PAs that lack distinct histological features of anaplasia can behave unpredictably, in a more aggressive manner, with leptomeningeal spreading. Genetic alterations resulting in aberrant signalling of the mitogen-activated protein kinase (MAPK) pathway have been considered to underlie the development of PAs. The most commonly identified KIAA1549-BRAF fusion is important for appropriate tumour molecular diagnosis. In this paper we summarize the clinicopathological presentation of PAs, with emphasis on their heterogeneous morphology, based on our own experience in the field of surgical neuropathology and the literature data. Diagnosis of pilocytic tumours requires careful analysis of clinical, histopathological and molecular features to avoid misinterpretation of these benign neoplastic lesions.


Asunto(s)
Astrocitos/citología , Astrocitoma/patología , Neoplasias Encefálicas/patología , Glioma/patología , Recurrencia Local de Neoplasia/patología , Animales , Astrocitoma/diagnóstico , Neoplasias Encefálicas/diagnóstico , Glioma/diagnóstico , Humanos , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Recurrencia Local de Neoplasia/diagnóstico
12.
Biochim Biophys Acta ; 1523(2-3): 189-95, 2000 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-11042383

RESUMEN

The effects of dopamine-melanin (DA-melanin), a synthetic model of neuromelanin, on peroxynitrite-mediated 3-nitrotyrosine formation, oxidation of tryptophan in bovine serum albumin and inactivation of erythrocyte membrane Ca(2+)-ATPase activity were investigated in the absence and in the presence of bicarbonate. DA-melanin inhibited nitration of free tyrosine, loss of tryptophan residues and Ca(2+)-ATPase inactivation by peroxynitrite in a dose dependent manner. In the presence of bicarbonate, this inhibitory effect was lower for nitration and insignificant for oxidative protein modifications. These results suggest that neuromelanin can protect against nitrating and oxidizing action of peroxynitrite but is a worse protector against the peroxynitrite-CO(2) adduct. As peroxynitrite may be a mediator of neurotoxic processes, the obtained results suggest that neuromelanin may be important as a physiological protector against peroxynitrite.


Asunto(s)
Antioxidantes/química , Antioxidantes/farmacología , ATPasas Transportadoras de Calcio/sangre , Melaninas/química , Melaninas/farmacología , Nitratos/farmacología , Triptófano/química , Tirosina/química , Animales , ATPasas Transportadoras de Calcio/antagonistas & inhibidores , Bovinos , Membrana Eritrocítica/enzimología , Humanos , Cinética , Nitratos/química , Oxidantes/farmacología , Oxidación-Reducción , Albúmina Sérica Bovina/química , Albúmina Sérica Bovina/efectos de los fármacos
13.
Biochim Biophys Acta ; 1116(1): 11-6, 1992 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-1540619

RESUMEN

The inhibiting effect of melanin synthesized from dihydroxyphenylalanine (DOPA), dopamine, adrenaline and adrenolutin on the ultraviolet- or the Fe(2+)-ascorbic acid-induced peroxidation of cardiolipin liposomes has been studied. All these melanins are able to inhibit both the ultraviolet- and the Fe(2+)-ascorbic acid-induced lipid peroxidation. Antioxidative activity of melanins enhances in the order: dopamine-melanin less than melanin synthesized from dopamine in the presence of Cu(2+) less than DOPA--melanin less than melanin synthesized from adrenaline in the presence of Cu(2+) approximately equal to adrenolutin-melanin, and correlates with their ability to scavenge superoxide anion radical. The optical screening effect of the investigated melanins in the inhibition of lipid peroxidation was not higher than 15% for the most active melanins.


Asunto(s)
Antioxidantes/farmacología , Cardiolipinas/química , Dihidroxifenilalanina/análogos & derivados , Liposomas/química , Melaninas/farmacología , Ácido Ascórbico , Cardiolipinas/efectos de la radiación , Dihidroxifenilalanina/síntesis química , Dihidroxifenilalanina/farmacología , Dopamina/análogos & derivados , Dopamina/farmacología , Epinefrina/análogos & derivados , Epinefrina/farmacología , Compuestos Ferrosos , Indoles/farmacología , Peroxidación de Lípido/efectos de los fármacos , Melaninas/síntesis química , Nitroazul de Tetrazolio/química , Fotoquímica , Rayos Ultravioleta
14.
Biochim Biophys Acta ; 997(1-2): 49-54, 1989 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-2546609

RESUMEN

Melanins synthesized from adrenaline and dopamine in the presence or absence of copper ions were characterized by pyrolysis-gas chromatography-mass spectrometry and by IR and ESR methods. It was shown that Cu2+ are able to induce changes in the melanin structure. Melanins obtained from adrenaline-Cu2+ and dopamine-Cu2+ complexes are composed mainly from monomeric units of the indole type. Melanins synthesized from these catecholamines without Cu2+ contain additionally large amounts of unindolized monomeric units. The structure differences in both types of melanins are reflected in their sorptive abilities and spectroscopic characteristics.


Asunto(s)
Cobre/fisiología , Dopamina/metabolismo , Epinefrina/metabolismo , Melaninas/biosíntesis , Cloroquina/metabolismo , Espectroscopía de Resonancia por Spin del Electrón , Cromatografía de Gases y Espectrometría de Masas , Técnicas In Vitro , Melaninas/análisis , Estructura Molecular , Espectrofotometría Infrarroja
15.
Biochem Pharmacol ; 31(21): 3359-65, 1982 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-6816244

RESUMEN

In order to elucidate the mechanism of drugs binding to melanin, effects of pH, ionic strength and organic solvent on the interaction of chloroquine with synthetic dopa-melanin were studied. The results indicate that electrostatic, hydrophobic and van der Waals' forces participate in the formation of the chloroquine-melanin complex. Binding analysis by the Scatchard method showed that two classes of binding sites take part in the complex formation: strong binding sites with the association constant k1 approximately to 10(5) and weak binding sites with K2 approximately 10(4). Experiments with chemically modified melanin yielded some information about binding sites of this biopolymer. The obtained results suggest that strong binding involves both hydrophobic interaction and electrostatic attraction between the protonated ring system of chloroquine and the ortho-semiquinone groups of melanin. However, the weakly reacting sites can be identified as ionic bonds between protonated aliphatic nitrogen of chloroquine molecule and carboxyl groups of melanin. Van der Waals' forces occurring at the conjunctions of the aromatic rings of the drug and the aromatic indole-nuclei of the melanin probably take part in the weak binding too.


Asunto(s)
Cloroquina , Dihidroxifenilalanina , Melaninas , Sitios de Unión , Fenómenos Químicos , Química , Concentración de Iones de Hidrógeno , Cinética , Concentración Osmolar , Cloruro de Sodio
16.
Acta Biochim Pol ; 37(1): 89-92, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-2087922

RESUMEN

Lecithin peroxidation in liposomal membranes induced by UV light was studied in the presence of natural eye melanin and synthetic melanins prepared from various precursors. It was shown that melanins inhibited lecithin photooxidation, and that the extent of this effect strongly depended on the type and concentration of melanin. Comparative study indicated that melanin obtained from adrenolutin was the most effective antioxidant. The ability to inhibit lipid peroxidation depends both on the concentration of paramagnetic centers in the melanin polymer and the accessibility of these centers for free radicals formed during irradiation of liposomes.


Asunto(s)
Peroxidación de Lípido , Liposomas , Melaninas , Fosfatidilcolinas/química , Cinética , Oxidación-Reducción , Fosfatidilcolinas/efectos de la radiación , Rayos Ultravioleta
17.
Acta Biochim Pol ; 47(4): 931-40, 2000.
Artículo en Inglés | MEDLINE | ID: mdl-11996116

RESUMEN

Peroxynitrite-mediated linoleic acid oxidation and tyrosine nitration were analysed in the presence of synthetic model neuromelanins: dopamine (DA) -melanin, cysteinyldopamine (CysDA) -melanin and various DA/CysDA copolymers. The presence of melanin significantly decreased the amount of 3-nitrotyrosine formed. This inhibitory effect depended on the type and concentration of melanin polymer. It was found that incorporation of CysDA-derived units into melanin attenuated its protective effect on tyrosine nitration induced by peroxynitrite. In the presence of bicarbonate, the melanins also inhibited 3-nitrotyrosine formation in a concentration dependent manner, although the extent of inhibition was lower than in the absence of bicarbonate. The tested melanins inhibited peroxynitrite-induced formation of linoleic acid hydroperoxides, both in the absence and in the presence of bicarbonate. In the presence of bicarbonate, among the oxidation products appeared 4-hydroxynonenal (HNE). CysDA-melanin inhibited the formation of HNE, while DA-melanin did not affect the aldehyde level. The results of the presented study suggest that neuromelanin can act as a natural scavenger of peroxynitrite.


Asunto(s)
Ácido Linoleico/metabolismo , Melaninas/metabolismo , Nitrógeno/metabolismo , Oxígeno/metabolismo , Ácido Peroxinitroso/metabolismo , Tirosina/análogos & derivados , Tirosina/metabolismo , Aldehídos/metabolismo , Cromatografía Líquida de Alta Presión , Reactivos de Enlaces Cruzados/metabolismo , Relación Dosis-Respuesta a Droga , Peróxido de Hidrógeno/farmacología
18.
Biophys Chem ; 35(2-3): 265-70, 1990 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-2118811

RESUMEN

It has been demonstrated that methotrexate forms stable complexes with melanin and melanosomes isolated from B16 melanoma. The number of binding sites and binding constants for methotrexate binding by intact melanosomes and melanin were n = 0.046 mumol/mg, K = 0.32 x 10(4) M-1 and n = 0.063 mumol/mg, K = 1.08 x 10(4) M-1, respectively. Binding of methotrexate to synthetic DOPA-melanin used for comparison also shows a single class of binding sites, n = 0.060 mumol/mg with binding constant K = 2.34 x 10(4) M-1. The possibility of side effects caused by methotrexate-melanin interactions after treatment of neoplasms is discussed.


Asunto(s)
Melaninas/metabolismo , Melanocitos/metabolismo , Melanoma Experimental/metabolismo , Metotrexato/metabolismo , Animales , Sitios de Unión , Dihidroxifenilalanina/análisis , Hidrólisis , Cinética , Metotrexato/análisis , Ratones , Ratones Endogámicos C57BL
19.
Neurotox Res ; 1(2): 141-7, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-12835109

RESUMEN

The oxidative pathway of dopamine metabolism in the human brain leads to formation and accumulation of neuromelanin in the cytoplasm of most nigrostriatal dopaminergic neurons. The physiological significance of neuromelanin and its contribution to the neurodegenerative processes underlying Parkinson's disease are still controversial. The effect of model neuromelanins on Fe(II)/ascorbate-induced lipid peroxidation in micelles of linoleic acid and in lecithin liposomes was determined. Synthetic neuromelanins were obtained from dopamine (DA), 5-S-cysteinyldopamine (CysDA) or from equimolar mixture of these precursors. Thiobarbituric acid test and reverse-phase HPLC, used for measurements of primary and secondary oxidation products, showed that all melanins tested significantly suppressed peroxidation of both, linoleic acid and liposomal lecithin. The inhibitory effect of CysDA-melanin was lower than of DA/CysDA-melanin and DA-melanin. All the melanins were able to reduce linoleic acid hydroperoxides to their stable hydroxy derivatives. The results obtained suggest that neuromelanin can act as natural antioxidant. The fatty acid hydroperoxide-reducing ability demonstrated for the model neuromelanins appears to be involved in the mechanism of antioxidative activity of neuromelanin.

20.
J Photochem Photobiol B ; 15(3): 223-31, 1992 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-1333525

RESUMEN

It was found that the yield of thiobarbituric acid reactive substances in UV-irradiated liposome membranes was significantly suppressed in the presence of catecholamine-melanins, indicating their ability to inhibit lipid peroxidation. The extent of inhibition depended on the type and concentration of melanin polymers. Melanin-copper complexes inhibited lecithin photooxidation less effectively than copper-free melanins derived from the same precursor. The antioxidant efficiency of melanins appears to be related to the levels of intrinsic and photo-induced free radical centers in the melanin polymer, as well as to accessibility of these centers for active species formed during irradiation of liposomes.


Asunto(s)
Catecolaminas , Peroxidación de Lípido , Melaninas , Fosfatidilcolinas/efectos de la radiación , Rayos Ultravioleta , Dihidroxifenilalanina , Dopamina , Espectroscopía de Resonancia por Spin del Electrón , Epinefrina , Indoles , Cinética , Norepinefrina
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