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1.
Eur Rev Med Pharmacol Sci ; 28(8): 3268-3274, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38708485

RESUMO

BACKGROUND: We describe the first case of a pediatric patient with acute intermittent porphyria and severe chronic porphyric neuropathy treated with givosiran, a small-interfering RNA that drastically decreases delta-aminolevulinic acid production and reduces porphyric attacks' recurrence. CASE REPORT: A 12-year-old male patient with refractory acute intermittent porphyria and severe porphyric neuropathy was followed prospectively for 12 months after givosiran initiation (subcutaneous, 2.5 mg/kg monthly). Serial neurological, structural, and resting-state functional magnetic resonance imaging (MRI) evaluations were performed, including clinical scales and neurophysiological tests. Delta-aminolevulinic acid urinary levels dropped drastically during treatment. In parallel, all the administered neurological rating scales and neurophysiological assessments showed improvement in all domains. Moreover, an improvement in central motor conduction parameters and resting-state functional connectivity in the sensory-motor network was noticed. At the end of the follow-up, the patient could walk unaided after using a wheelchair for 5 years. CONCLUSIONS: A clear beneficial effect of givosiran was demonstrated in our patient with both clinical and peripheral nerve neurophysiologic outcome measures. Moreover, we first reported a potential role of givosiran in recovering central motor network impairment in acute intermittent porphyria (AIP), which was previously unknown. This study provides Class IV evidence that givosiran improves chronic porphyric neuropathy.


Assuntos
Acetilgalactosamina/análogos & derivados , Porfiria Aguda Intermitente , Humanos , Masculino , Porfiria Aguda Intermitente/tratamento farmacológico , Criança , Acetilgalactosamina/uso terapêutico , Ácido Aminolevulínico/análogos & derivados , Ácido Aminolevulínico/urina , Imageamento por Ressonância Magnética , Pirrolidinas/uso terapêutico , Uridina/análogos & derivados , Uridina/uso terapêutico , Uridina/administração & dosagem , Recuperação de Função Fisiológica , Doença Crônica , Resultado do Tratamento
3.
Intern Emerg Med ; 18(8): 2311-2319, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37751084

RESUMO

BACKGROUND: SARS- CoV-2 virus has had dramatic consequences worldwide being able to cause acute respiratory distress syndrome (ARDS), massive thrombosis and pulmonary embolism and, finally, patients' death. In COVID-19 infection, platelets have a procoagulant phenotype that can cause thrombosis in the pulmonary and systemic vascular network. Aspirin is a well-known anti-platelet drug widely used for the prevention of cardiovascular events and systematic reviews suggest a possible benefit of low-dose aspirin (LDA) use in the prevention and treatment of ARDS in patients with COVID-19 infection. However, several studies are available in the literature which do not support any benefits and no association with the patients' outcome. Therefore, currently available data are inconclusive. MATERIALS AND PATIENTS: Data from the nationwide cohort multicenter study of the Italian Society of Internal Medicine (SIMI) were analyzed. We conducted a propensity score-matched cohort analysis to investigate the impact of chronic assumption of LDA on mortality of adult COVID-19 patients admitted in Internal Medicine Units (IMU). Data from 3044 COVID-19 patients who referred to 41 Italian hospitals between February 3rd to May 8th 2020 were analyzed. A propensity score-matched analysis was conducted using the following variables: age, sex, hypertension, hyperlipidemia diabetes, atrial fibrillation, cerebrovascular disease, COPD, CKD and stratified upon LDA usage, excluding anticoagulant treatment. After matching, 380 patients were included in the final analysis (190 in LDA group and 190 in no-LDA group). RESULTS: 66.2% were male, median age was 77 [70-83]. 34.8% of the population died during the hospitalization. Cardiovascular diseases were not significantly different between the groups. After comparison of LDA and no-LDA subgroups, we didn't record a significant difference in mortality rate (35.7% vs 33.7%) duration of hospital stay and ICU admission. In a logistic regression model, age (OR 1.05; 95% CI 1.01-1.09), FiO2 (OR 1.024; 95% CI 1.03-1.04) and days between symptoms onset and hospitalization (OR 0.93; 95% CI 0.87-0.99) were the only variables independently associated with death.


Assuntos
Aspirina , COVID-19 , Idoso , Feminino , Humanos , Masculino , Aspirina/uso terapêutico , Estudos de Coortes , COVID-19/complicações , COVID-19/terapia , Pontuação de Propensão , Sistema de Registros , Síndrome do Desconforto Respiratório , SARS-CoV-2 , Trombose , Estudos Multicêntricos como Assunto , Idoso de 80 Anos ou mais
4.
Eur J Intern Med ; 97: 69-77, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34844795

RESUMO

AIMS: To evaluate pulmonary and intravascular congestion at admission and repeatedly during hospitalization for acute decompensated heart failure (ADHF) in HFrEF and HFpEF patients using lung (LUS) and inferior vena cava (IVC) ultrasound. METHODS AND RESULTS: Three-hundred-fourteen patients (82±9 years; HFpEF =172; HFrEF=142) admitted to Internal Medicine wards for ADHF were enrolled in a multi-center prospective study. At admission HFrEF presented higher indexes of pulmonary and intravascular congestion (LUS-score: 0.9 ±â€¯0.4 vs 0.7 ±â€¯0.4; p<0.01; IVC end-expiratory diameter: 21.6 ±â€¯5.1 mm vs 20±5.5 mm, p<0.01; IVC collapsibility index 24.4 ±â€¯17.4% vs 30.9 ±â€¯21.1% p<0.01) and higher Nt-proBNP values (8010 vs 3900 ng/l; p<0.001). At discharge, HFrEF still presented higher B-scores (0.4 ±â€¯4 vs 0.3 ±â€¯0.4; p = 0.023), while intravascular congestion improved to a greater extent, thus IVC measurements were similar in the two groups. No differences in diuretic doses, urine output, hemoconcentration, worsening renal function were found. At 90-days follow up HF readmission/death did not differ in HFpEF and HFrEF (28% vs 31%, p = 0,48). Residual congestion was associated with HF readmission/death considering the whole population; while intravascular congestion predicted readmission/death in the HFrEF, no association between sonographic indexes and the outcome was found in HFpEF. CONCLUSIONS: Serial assessment of pulmonary and intravascular congestion revealed a higher burden of fluid overload in HFrEF and, conversely, a greater reduction in intravascular venous congestion with diuretic treatment. Although other factors beyond EF could play a role in congestion/decongestion patterns, our data may be relevant for further phenotyping HF patients, considering the importance of decongestion optimization in the clinical approach.


Assuntos
Insuficiência Cardíaca , Diuréticos/uso terapêutico , Insuficiência Cardíaca/complicações , Insuficiência Cardíaca/tratamento farmacológico , Insuficiência Cardíaca/epidemiologia , Hospitalização , Humanos , Prognóstico , Estudos Prospectivos , Volume Sistólico
5.
Am J Gastroenterol ; 113(3): 368-375, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29257146

RESUMO

OBJECTIVES: Thrombocytopenia is a hallmark for patients with cirrhosis and it is perceived as a risk factor for bleeding events. However, the relationship between platelet count and bleeding is still unclear. METHODS: We investigated the relationship between platelet count and major or clinical relevant nonmajor bleedings during a follow-up of ∼4 years. RESULTS: A total of 280 cirrhotic patients with different degrees of liver disease (67% males; age 64±37 years; 47% Child-Pugh B and C) were followed up for a median of 1,129 (interquartile range: 800-1,498) days yielding 953.12 patient-year of observation. The annual rate of any significant bleeding was 5.45%/year (3.57%/year and 1.89%/year for major and minor bleeding, respectively). Fifty-two (18.6%) patients experienced a major (n=34) or minor (n=18) bleeding event, predominantly from gastrointestinal origin. Platelet counts progressively decreased with the worsening of liver disease and were similar in patients with or without major or minor bleeding: a platelet count ≤50 × 103/µl was detected in 3 (6%) patients with and in 20 (9%) patients without any bleeding event. Conversely, prothrombin time-international normalized ratio was slightly higher in patients with overall or major bleeding. On Cox proportional hazard analysis, only a previous gastrointestinal bleeding (hazard ratio (HR): 1.96; 95% confidence interval: 1.11-3.47; P=0.020) and encephalopathy (HR: 2.05; 95% confidence interval: 1.16-3.62; P=0.013) independently predicted overall bleeding events. CONCLUSIONS: Platelet count does not predict unprovoked major or minor bleeding in cirrhotic patients.


Assuntos
Hemorragia Gastrointestinal/epidemiologia , Cirrose Hepática/epidemiologia , Trombocitopenia/epidemiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Seguimentos , Hemorragia/epidemiologia , Humanos , Coeficiente Internacional Normatizado , Itália/epidemiologia , Cirrose Hepática/sangue , Masculino , Pessoa de Meia-Idade , Contagem de Plaquetas , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Tempo de Protrombina , Fatores de Risco , Índice de Gravidade de Doença
6.
J Mater Chem B ; 3(5): 814-823, 2015 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32262172

RESUMO

A-B block copolymer micelles comprised of thermoresponsive hydrophilic PNIPAAm (poly(N-isopropylacrylamide)) coronae and hydrophobic PNP (poly(N-acryloyl-2-pyrrolidone)), PMNP (poly(N-acryloyl-5-methoxy-2-pyrrolidone)), or PBNP (poly(N-acryloyl-5-butoxy-2-pyrrolidone)) cores were examined to identify how systematic adjustments to core-segment structure affect micellar physicochemical properties, drug loading efficiency (DLE), and thermoresponsive drug release among these novel systems. Critical micelle concentrations (CMCs) were found to decrease by two orders of magnitude in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP indicating that minor modifications to the pyrrolidone scaffold significantly affect its hydrophobic character. Moreover, the structural modifications were also found to influence micelle size and intermicellar aggregation that occurs above the lower critical solution temperature (LCST). In line with the CMC data, DLE values of doxorubicin-loaded (i.e., DOX-loaded) micelles increase in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP, a trend attributed to enhanced cohesive forces (i.e. London dispersion forces) between DOX and core as the latter becomes more hydrophobic. When heated above the LCST, DOX release decreases in the order of PNIPAAm-PNP, PNIPAAm-PMNP, and PNIPAAm-PBNP suggesting that release processes are impeded by the cohesive forces responsible for efficient encapsulation. Finally, cytotoxicity assays performed above the LCST reveal that DOX-loaded micelles are as cytotoxic as the free drug in formulations where DOX concentrations are equivalent.

9.
Clin Genet ; 67(5): 425-8, 2005 May.
Artigo em Inglês | MEDLINE | ID: mdl-15811010

RESUMO

A large variety of mutations within the genes encoding hepcidin (HAMP) and hemojuvelin (HJV) have been identified in patients with the severe iron overload disorder juvenile hemochromatosis (JH). The aim of the present study was to evaluate the molecular background of JH in patients from central parts of Europe. Sequence analyses of HAMP and HJV were performed in seven JH patients from six families from Germany, Slovakia, and Croatia. For detection of the G320V mutation in HJV, a rapid polymerase chain reaction-based assay was developed. No mutations were found within the HAMP gene. Six of seven (86%) JH patients carried at least one copy of the G320V mutation within the HJV gene. Four of these patients were homozygous for the G320V mutation. In addition, two novel HJV mutations were identified (C119F and S328fsX337). Taken together, the present study demonstrates that molecular analysis of the HJV gene is a powerful tool for an early and reliable diagnosis of JH. As in affected patients from Greece, the G320V mutation seems to be widely distributed among JH patients from central parts of Europe. Therefore, detection of the G320V mutation could identify the majority of JH cases from these regions non-invasively.


Assuntos
Análise Mutacional de DNA , Hemocromatose/diagnóstico , Hemocromatose/genética , Proteínas de Membrana/genética , Adolescente , Adulto , Peptídeos Catiônicos Antimicrobianos/genética , Europa (Continente) , Feminino , Proteínas Ligadas por GPI , Genética Populacional , Proteína da Hemocromatose , Hepcidinas , Humanos , Masculino , Reação em Cadeia da Polimerase , Análise de Sequência de DNA
10.
J Membr Biol ; 206(1): 3-7, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-16440176

RESUMO

To investigate the functional significance of mutations in Ferroportin that cause hereditary iron overload, we directly measured the iron efflux activity of the proteins expressed in Xenopus oocytes. We found that wild type and mutant Ferroportin molecules (A77D, N144H, Q248H and V162Delta) were all expressed at the plasma membrane at similar levels. All mutations caused significant reductions in (59)Fe efflux compared to wild type but all retained some residual transport activity. A77D had the strongest effect on (59)Fe efflux (remaining activity 9% of wild-type control), whereas the N144H mutation retained the highest efflux activity (42% of control). The Q248H and V162Delta mutations were intermediate between these values. Co-injection of mutant and wild-type mRNAs revealed that the A77D and N144H mutations had a dominant negative effect on the function of the WT protein.


Assuntos
Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Hemocromatose/genética , Hemocromatose/metabolismo , Ferro/metabolismo , Oócitos/metabolismo , Animais , Transporte Biológico Ativo , Células Cultivadas , Humanos , Mutagênese Sítio-Dirigida , Relação Estrutura-Atividade , Xenopus laevis
11.
Gut ; 52 Suppl 2: ii23-30, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12651879

RESUMO

Iron is an important component of the Earth's crust, but its own chemistry greatly limits utilisation and also sets the basis for its toxicity. The capacity of readily exchanging electrons in aerobic conditions makes iron essential for fundamental cell functions, such as DNA synthesis, transport of oxygen and electrons, and cell respiration. On the other hand, as humans have no means to control iron excretion, excess iron, regardless of the route of entry, accumulates in parenchymal organs and threatens cell viability. In fact, a number of disease states (that is, iron overload diseases) attributable to genetic or acquired factors are pathogenetically linked to excess body iron stores and iron removal therapy is an effective lifesaving strategy in such circumstances.


Assuntos
Hemocromatose/genética , Árvores de Decisões , Testes Genéticos/métodos , Hemocromatose/diagnóstico , Proteína da Hemocromatose , Antígenos de Histocompatibilidade Classe I/genética , Humanos , Ferro/metabolismo , Sobrecarga de Ferro/genética , Proteínas de Membrana/genética , Mutação
12.
Ann Ital Med Int ; 16(1): 46-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11688350

RESUMO

Early erroneous diagnosis of rheumatic disease is common in subjects with arthropathy due to hereditary hemochromatosis. A 71-year-old male with chronic obstructive pulmonary disease and monoclonal gammopathy underwent hip replacement and was referred to our Department because of altered liver function tests. Test results were negative for hepatitis B surface antigen and hepatitis C virus, and positive for rheumatoid factor. A diagnosis of rheumatoid arthritis had been made on the basis of compatible joint involvement and laboratory data and steroid treatment prescribed. Since his serum ferritin was 3249 ng/mL, genetic testing for hereditary hemochromatosis was carried out and revealed homozygosity for Cys282Tyr mutation in the HFE gene. Liver biopsy disclosed cirrhosis compatible with hemochromatosis. Following a review of the patients' radiographs, the diagnosis of hemochromatosis arthropathy was made. Phlebotomies and family screening for hereditary hemochromatosis were done. The most logical explanation for the positive rheumatoid factor result in this subject are his age and the presence of two chronic diseases involving long-standing antigenic stimulation and monoclonal gammopathy of uncertain significance. It is important to distinguish rheumatoid arthritis from hemochromatosis arthropathy for several reasons: patients with hereditary hemochromatosis do not require corticosteroid treatment; in case of erroneous diagnosis of rheumatoid arthritis, phlebotomy is not started early, and familial genetic counseling is not considered. In male subjects with positive rheumatoid factor and joint and liver disease, hereditary hemochromatosis should be considered. More liberal use of genetic testing is justified in such cases.


Assuntos
Artrite Reumatoide/diagnóstico , Hemocromatose/diagnóstico , Hemocromatose/genética , Idoso , Diagnóstico Diferencial , Humanos , Masculino
13.
Bioorg Med Chem ; 9(11): 3041-7, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11597487

RESUMO

Increasing evidence suggests that iron plays an important role in tissue damage both during chronic iron overload diseases (i.e., hemochromatosis) and when, in the absence of actual tissue iron overload, iron is delocalised from specific carriers or intracellular sites (inflammation, neurodegenerative diseases, post-ischaemic reperfusion, etc.). In order to be used for therapeutical purposes in vivo, a reliable iron chelator should be capable of preventing the undesired effects that follow the electrochemical activation of iron (see below). Bearing in mind the molecular structure of some flavonols that are able to chelate iron, we synthesised a new oral iron-chelator, 2-methyl-3-hydroxy-4H-benzopyran-4-one (MCOH). We demonstrate that MCOH chelates iron in a 2:1 ratio showing a stability constant of approximately 10(10). MCOH is able to cross cell membranes (erythrocytes, ascite tumour cells) in both directions. Following intraperitoneal administration to rats, it is quickly taken up by the liver and excreted in the urine within 24h. A similar behaviour has been documented after oral administration. We propose that MCOH may represent the prototype of a new class of iron chelating agents to be developed for iron-removal therapy in vivo with the goal of preventing tissue damage caused by the iron redox cycle.


Assuntos
Benzopiranos/farmacocinética , Cromonas/farmacocinética , Quelantes de Ferro/síntese química , Administração Oral , Animais , Benzopiranos/síntese química , Benzopiranos/metabolismo , Cromonas/síntese química , Cromonas/metabolismo , Desenho de Fármacos , Eritrócitos , Fezes/química , Quelantes de Ferro/metabolismo , Quelantes de Ferro/farmacocinética , Fígado/química , Masculino , Estrutura Molecular , Ratos , Ratos Sprague-Dawley , Células Tumorais Cultivadas , Urina/química
14.
J Clin Invest ; 108(4): 619-23, 2001 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-11518736

RESUMO

Hemochromatosis is a progressive iron overload disorder that is prevalent among individuals of European descent. It is usually inherited in an autosomal-recessive pattern and associated with missense mutations in HFE, an atypical major histocompatibility class I gene. Recently, we described a large family with autosomal-dominant hemochromatosis not linked to HFE and distinguished by early iron accumulation in reticuloendothelial cells. Through analysis of a large pedigree, we have determined that this disease maps to 2q32. The gene encoding ferroportin (SLC11A3), a transmembrane iron export protein, lies within a candidate interval defined by highly significant lod scores. We show that the iron-loading phenotype in autosomal-dominant hemochromatosis is associated with a nonconservative missense mutation in the ferroportin gene. This missense mutation, converting alanine to aspartic acid at residue 77 (A77D), was not seen in samples from 100 unaffected control individuals. We propose that partial loss of ferroportin function leads to an imbalance in iron distribution and a consequent increase in tissue iron accumulation.


Assuntos
Substituição de Aminoácidos , Proteínas de Transporte/genética , Proteínas de Transporte de Cátions , Cromossomos Humanos Par 2/genética , Genes Dominantes , Hemocromatose/genética , Proteínas de Membrana/genética , Sistema Fagocitário Mononuclear/metabolismo , Mutação de Sentido Incorreto , Animais , Proteínas de Transporte/fisiologia , Códon/genética , Éxons/genética , Feminino , Heterogeneidade Genética , Antígenos HLA/genética , Hemocromatose/epidemiologia , Proteína da Hemocromatose , Antígenos de Histocompatibilidade Classe I/genética , Homeostase , Humanos , Ferro/metabolismo , Sobrecarga de Ferro/genética , Sobrecarga de Ferro/metabolismo , Itália/epidemiologia , Escore Lod , Masculino , Proteínas de Membrana/deficiência , Proteínas de Membrana/fisiologia , Camundongos , Linhagem , Fenótipo , Receptores da Transferrina/genética
15.
J Hepatol ; 34(4): 523-8, 2001 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-11394651

RESUMO

BACKGROUND/AIMS: The actual prevalence of the main hemochromatosis (HFE) mutations in the Italian adult population and their phenotypic expression have not yet been established. This information is key to advocate a mass-screening program. METHODS: Two thousand one hundred adults were tested for the C282Y/H63D HFE gene mutations by an automated genotyping assay as well as transferrin saturation (TS) and serum ferritin levels. RESULTS: No homozygotes for the C282Y mutation were found. Heterozygosity for the C282Y mutation was 3.1%, while heterozygosity and homozygosity for the H63D mutation were 21.5% and 2.5%, respectively. TS was significantly higher in C282Y heterozygotes and H63D homozygotes as compared to wild-type individuals (P < 0.01). Interestingly, of the HFE wild-type subjects 5.9% had a TS value above the 45% threshold. CONCLUSIONS: This study shows that (i) the predicted prevalence for C282Y homozygosity in Italy is 1:3900; (ii) the C282Y/H63D wild-type population has an increased baseline of iron parameters possibly due to genetic factors not linked to the C282Y/H63D mutations; (iii) since in the latter population the actual tissue iron burden cannot be assessed, phenotypic (TS) screening in Italy is not recommended until the true prevalence of all mutations in the HFE gene and in other hemochromatosis genes will be established.


Assuntos
Expressão Gênica , Antígenos HLA/genética , Hemocromatose/genética , Antígenos de Histocompatibilidade Classe I/genética , Proteínas de Membrana , Mutação , Adulto , Feminino , Frequência do Gene , Proteína da Hemocromatose , Heterozigoto , Homozigoto , Humanos , Itália , Masculino , Pessoa de Meia-Idade , Valores de Referência , Transferrina/análise
16.
Gastroenterology ; 120(6): 1412-9, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11313311

RESUMO

BACKGROUND & AIMS: Imbalances of iron homeostasis are accompanied by alterations of intestinal iron absorption. The identification of divalent-metal transporter 1 (DMT1) and ferroportin 1 (FP1) has improved our understanding of transmembrane iron trafficking. To gain insight into the regulatory properties of these transporters in the duodenum, we studied their expression in patients with hereditary hemochromatosis (HFE-associated and non-HFE-associated), secondary iron overload, and iron deficiency. METHODS: DMT1, FP1 messenger RNA (mRNA), and protein expression were analyzed in duodenal biopsy specimens from patients by means of TaqMan real-time polymerase chain reaction, Western blotting technique, and immunohistochemistry. RESULTS: DMT1 and FP1 mRNA levels are positively correlated with each other in all patient groups (P < 0.001). Moreover, DMT1 and FP1 mRNA levels were significantly increased in patients with iron deficiency, HFE and non-HFE hemochromatosis, whereas they were unchanged in patients with secondary iron overload. Alterations in DMT1 and FP1 mRNA levels were paralleled by comparable changes in the duodenal expression of these proteins. In patients with normal iron status or iron deficiency, significant negative correlations between DMT1, FP1 mRNA, and serum iron parameters were found, which were absent in subjects with primary hemochromatosis. CONCLUSIONS: DMT1 and FP1 are centrally involved in iron uptake/transfer in the duodenum and in the adaptive changes of iron homeostasis to iron deficiency and overload.


Assuntos
Proteínas de Transporte/genética , Proteínas de Transporte de Cátions , Duodeno/metabolismo , Deficiências de Ferro , Sobrecarga de Ferro/metabolismo , Proteínas de Ligação ao Ferro , Adulto , Idoso , Proteínas de Transporte/análise , Feminino , Gliceraldeído-3-Fosfato Desidrogenases/genética , Hemocromatose/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , RNA Mensageiro/análise
17.
Pharmacology ; 62(2): 107-12, 2001 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-11174081

RESUMO

Complexation of ursodeoxycholic acid (UDCA) with 2-hydroxypropyl-beta-cyclodextrin (HPbetaCD) improves the water solubility and the dissolution rate of UDCA and may therefore increase its bioavailability. We compared the amount and the rate of biliary excretion of UDCA and biliary lipid secretion after a single oral administration of UDCA in 3 different pharmaceutical formulations [UDCA-HPbetaCD ('urso-beta-cyclodextrin'), UDCA suspension and UDCA capsule] at 3 different dosages each, in 11 groups (2 control groups) of bile fistula rats. UDCA excretion increased with an increase in dose, biliary UDCA recovery and peak secretion were significantly higher after administration of UDCA-HPbetaCD than after UDCA in suspension or capsule. This enhancement of biliary excretion may achieve greater UDCA enrichment in the bile acid pool than conventional pharmaceutical UDCA formulations, this giving to UDCA-HPbetaCD a considerable therapeutical potential.


Assuntos
Bile/metabolismo , Ciclodextrinas/farmacocinética , Ácido Ursodesoxicólico/farmacocinética , beta-Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Administração Oral , Animais , Fístula Biliar , Disponibilidade Biológica , Química Farmacêutica , Combinação de Medicamentos , Masculino , Ratos , Ratos Sprague-Dawley
18.
Biochem J ; 352 Pt 2: 241-50, 2000 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-11085915

RESUMO

The capacity of readily exchanging electrons makes iron not only essential for fundamental cell functions, but also a potential catalyst for chemical reactions involving free-radical formation and subsequent oxidative stress and cell damage. Cellular iron levels are therefore carefully regulated in order to maintain an adequate substrate while also minimizing the pool of potentially toxic 'free iron'. Iron homoeostasis is controlled through several genes, an increasing number of which have been found to contain non-coding sequences [i.e. the iron-responsive elements (IREs)] which are recognized at the mRNA level by two cytoplasmic iron-regulatory proteins (IRP-1 and IRP-2). The IRPs belong to the aconitase superfamily. By means of an Fe-S-cluster-dependent switch, IRP-1 can function as an mRNA-binding protein or as an enzyme that converts citrate into isocitrate. Although structurally and functionally similar to IRP-1, IRP-2 does not seem to assemble a cluster nor to possess aconitase activity; moreover, it has a distinct pattern of tissue expression and is modulated by means of proteasome-mediated degradation. In response to fluctuations in the level of the 'labile iron pool', IRPs act as key regulators of cellular iron homoeostasis as a result of the translational control of the expression of a number of iron metabolism-related genes. Conversely, various agents and conditions may affect IRP activity, thereby modulating iron and oxygen radical levels in different pathobiological settings. As the number of mRNAs regulated through IRE-IRP interactions keeps growing, the definition of IRPs as iron-regulatory proteins may in the near future become limiting as their role expands to other essential metabolic pathways.


Assuntos
Proteínas Ferro-Enxofre/fisiologia , Ferro/metabolismo , Proteínas de Ligação a RNA/fisiologia , Divisão Celular , Hipóxia Celular , Homeostase , Proteína 1 Reguladora do Ferro , Proteína 2 Reguladora do Ferro , Proteínas Reguladoras de Ferro , Estresse Oxidativo , Xenobióticos/farmacologia
19.
Blood ; 96(3): 1125-9, 2000 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-10910932

RESUMO

Hereditary hemochromatosis (HC) is one of the most common single-gene hereditary diseases. A phenotypic hallmark of HC is low iron in reticuloendothelial cells in spite of body iron overload. Most patients with HC have the same mutation, a change of cysteine at position 282 to tyrosine (C282Y) in the HFE protein. The role of HFE in iron metabolism and the basis for the phenotypic abnormalities of HC are not understood. To clarify the role of HFE in the phenotypic expression of HC, we studied monocytes-macrophages from subjects carrying the C282Y mutation in the HFE protein and clinically expressing HC and transfected them with wild-type HFE by using an attenuated Salmonella typhimurium strain as a gene carrier. The Salmonella system allowed us to deliver genes of interest specifically to monocytes-macrophages with high transduction efficiency. The accumulation of (55)Fe delivered by (55)Fe-Tf was significantly lower in macrophages from patients with HC than from controls expressing wild-type HFE. Transfection of HC macrophages with the HFE gene resulted in a high level of expression of HFE protein at the cell surface. The accumulation of (55)Fe delivered by (55)Fe-Tf was raised by 40% to 60%, and this was reflected by an increase in the (55)Fe-ferritin pool within the HFE-transfected cells. These results suggest that the iron-deficient phenotype of HC macrophages is a direct effect of the HFE mutation, and they demonstrate a role for HFE in the accumulation of iron in these cells.


Assuntos
Técnicas de Transferência de Genes , Vetores Genéticos , Antígenos HLA/genética , Antígenos HLA/metabolismo , Hemocromatose/genética , Hemocromatose/metabolismo , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Macrófagos/metabolismo , Proteínas de Membrana , Monócitos/metabolismo , Salmonella typhimurium , Células Cultivadas , Terapia Genética , Hemocromatose/terapia , Proteína da Hemocromatose , Humanos , Ferro/metabolismo , Transferrina/metabolismo
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