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1.
Magy Onkol ; 62(4): 237-241, 2018 Dec 12.
Artigo em Húngaro | MEDLINE | ID: mdl-30540866

RESUMO

The atypical teratoid/rhabdoid tumour (ATRT) is a rare type of central nervous system tumour appearing usually under 2 years of age. The survival of patients is insufficient despite the combined treatment (neurosurgical removal, intensive chemo- and radiotherapy). ATRT recurs one year after completion of treatment in 60% of cases. Maintaining appropriate nutritional status during treatment is of great importance in this young age group. Nutritional treatment of patients with ATRT is especially difficult due to young age and possible neurological sequelae. A successful case of a three-month-old female infant is presented, with special emphasis on the importance of feeding therapy.


Assuntos
Terapia Nutricional/métodos , Tumor Rabdoide/diagnóstico por imagem , Tumor Rabdoide/terapia , Neoplasias da Base do Crânio/diagnóstico por imagem , Neoplasias da Base do Crânio/terapia , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/patologia , Neoplasias Encefálicas/terapia , Terapia Combinada , Feminino , Seguimentos , Humanos , Hungria , Lactente , Imageamento por Ressonância Magnética/métodos , Masculino , Doenças Raras , Tumor Rabdoide/patologia , Medição de Risco , Neoplasias da Base do Crânio/patologia , Fatores de Tempo
2.
J Pharm Biomed Anal ; 139: 54-64, 2017 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-28273651

RESUMO

Malignant melanoma is the most aggressive form of skin cancer. The early detection of primary melanoma tumors and metastases using non-invasive PET imaging determines the outcome of this disease. Previous studies have shown that benzamide derivatives (e.g. procainamide) conjugated with PET radionuclides specifically bind to melanin pigment of melanoma tumors. 68Ga chelating agents can have high influence on physiological properties of 68Ga labeled bioactive molecules, as was experienced during the application of HBED-CC on PSMA ligand. The aim of this study was to assess this concept in the case of the melanin specific procaindamide (PCA) and to compare the melanin specificity of 68Ga-labeled PCA using HBED-CC and NODAGA chelators under in vitro and in vivo conditions. Procainamide (PCA) was conjugated with HBED-CC and NODAGA chelators and was labeled with Ga-68. The melanin specificity of 68Ga-HBED-CC-PCA and 68Ga-NODAGA-PCA was investigated in vitro and in vivo using amelanotic (MELUR and A375) and melanin containing (B16-F10) melanoma cell lines. Tumor-bearing mice were prepared by subcutaneous injection of B16-F10, MELUR and A375 melanoma cells into C57BL/6 and SCID mice. 21±2days after tumor cell inoculation and 90min after intravenous injection of the 68Ga-labelledlabeled radiopharmacons whole body PET/MRI scans were performed. 68Ga-NODAGA-PCA and 68Ga-HBED-CC-PCA were produced with excellent radiochemical purity (98%). In vitro experiments demonstrated that after 30 and 90min incubation time 68Ga-NODAGA-PCA uptake of B16-F10 cells was significantly (p≤0.01) higher than the 68Ga-HBED-CC-conjugated PCA accumulation in the same cell line. Furthermore, significant difference (p≤0.01 and 0.05) was found between the uptake of melanin negative and positive cell lines using 68Ga-NODAGA-PCA and 68Ga-HBED-CC-PCA. In vivo PET/MRI studies using tumor models revealed significantly (p≤0.01) higher 68Ga-NODAGA-PCA uptake (SUVmean: 0.46±0.05, SUVmax: 1.96±0.25,T/M ratio: 40.7±4.23) in B16-F10 tumors in contrast to 68Ga-HBED-CC-PCA where the SUVmean, SUVmax and T/M ratio were 0.13±0.01, 0.56±0.11 and 11.43±1.24, respectively. Melanin specific PCA conjugated with NODAGA chelator showed higher specific binding properties than conjugated with HBED-CC. The chemical properties of the bifunctional chelators used for 68Ga-labeling of PCA determine the biological behaviour of the probes. Due to the high specificity and sensitivity 68Ga-labeled PCA molecules are promising radiotracers in melanoma imaging.


Assuntos
Acetatos/metabolismo , Ácido Edético/análogos & derivados , Radioisótopos de Gálio/metabolismo , Compostos Heterocíclicos com 1 Anel/metabolismo , Melanoma Experimental/metabolismo , Procainamida/metabolismo , Neoplasias Cutâneas/metabolismo , Animais , Avaliação Pré-Clínica de Medicamentos/métodos , Ácido Edético/metabolismo , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Melanoma Experimental/diagnóstico por imagem , Camundongos , Camundongos Endogâmicos C57BL , Camundongos SCID , Tomografia por Emissão de Pósitrons/métodos , Neoplasias Cutâneas/diagnóstico por imagem , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
3.
Clin Infect Dis ; 64(8): 1081-1088, 2017 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-28158685

RESUMO

Background: Airway-colonization by Staphylococcus aureus predisposes to the development of ventilator-associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). Despite extensive antibiotic treatment of intensive care unit patients, limited data are available on the efficacy of antibiotics on bacterial airway colonization and/or prevention of infections. Therefore, microbiologic responses to antibiotic treatment were evaluated in ventilated patients. Methods: Results of semiquantitative analyses of S. aureus burden in serial endotracheal-aspirate (ETA) samples and VAT/VAP diagnosis were correlated to antibiotic treatment. Minimum inhibitory concentrations of relevant antibiotics using serially collected isolates were evaluated. Results: Forty-eight mechanically ventilated patients who were S. aureus positive by ETA samples and treated with relevant antibiotics for at least 2 consecutive days were included in the study. Vancomycin failed to reduce methicillin-resistant S. aureus (MRSA) or methicillin-susceptible S. aureus (MSSA) burden in the airways. Oxacillin was ineffective for MSSA colonization in approximately 30% of the patients, and responders were typically coadministered additional antibiotics. Despite antibiotic exposure, 15 of the 39 patients (approximately 38%) colonized only by S. aureus and treated with appropriate antibiotic for at least 2 days still progressed to VAP. Importantly, no change in antibiotic susceptibility of S. aureus isolates was observed during treatment. Staphylococcus aureus colonization levels inversely correlated with the presence of normal respiratory flora. Conclusions: Antibiotic treatment is ineffective in reducing S. aureus colonization in the lower airways and preventing VAT or VAP. Staphylococcus aureus is in competition for colonization with the normal respiratory flora. To improve patient outcomes, alternatives to antibiotics are urgently needed.


Assuntos
Antibacterianos/uso terapêutico , Portador Sadio/microbiologia , Respiração Artificial/efeitos adversos , Sistema Respiratório/microbiologia , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/isolamento & purificação , Adulto , Idoso , Idoso de 80 Anos ou mais , Antibioticoprofilaxia/métodos , Carga Bacteriana , Bronquite/microbiologia , Bronquite/prevenção & controle , Portador Sadio/prevenção & controle , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pessoa de Meia-Idade , Pneumonia Bacteriana/microbiologia , Pneumonia Bacteriana/prevenção & controle , Infecções Estafilocócicas/prevenção & controle , Staphylococcus aureus/efeitos dos fármacos , Falha de Tratamento
4.
Int J Mol Sci ; 17(7)2016 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-27376279

RESUMO

Electron microscopy was used to test whether or not (a) in statu nascendi synthesized, and in situ measured, nanoparticle size does not differ significantly from the size of nanoparticles after their purification; and (b) the generation of selenium is detrimental to the bacterial strains that produce them. Elemental nano-sized selenium produced by probiotic latic acid bacteria was used as a lactomicroselenium (lactomicroSel) inhibitor of cell growth in the presence of lactomicroSel, and was followed by time-lapse microscopy. The size of lactomicroSel produced by probiotic bacteria was measured in situ and after isolation and purification. For these measurements the TESLA BS 540 transmission electron microscope was converted from analog (aTEM) to digital processing (dTEM), and further to remote-access internet electron microscopy (iTEM). Lactobacillus acidophilus produced fewer, but larger, lactomicroSel nanoparticles (200-350 nm) than Lactobacillus casei (L. casei), which generated many, smaller lactomicroSel particles (85-200 nm) and grains as a cloudy, less electrodense material. Streptococcus thermophilus cells generated selenoparticles (60-280 nm) in a suicidic manner. The size determined in situ in lactic acid bacteria was significantly lower than those measured by scanning electron microscopy after the isolation of lactomicroSel particles obtained from lactobacilli (100-500 nm), but higher relative to those isolated from Streptococcus thermopilus (50-100 nm). These differences indicate that smaller lactomicroSel particles could be more toxic to the producing bacteria themselves and discrepancies in size could have implications with respect to the applications of selenium nanoparticles as prebiotics.


Assuntos
Nanopartículas/química , Probióticos/metabolismo , Selênio/química , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Humanos , Lactobacillus acidophilus/efeitos dos fármacos , Lactobacillus acidophilus/crescimento & desenvolvimento , Lacticaseibacillus casei/efeitos dos fármacos , Lacticaseibacillus casei/crescimento & desenvolvimento , Microscopia Eletrônica , Nanopartículas/toxicidade , Tamanho da Partícula , Streptococcus thermophilus/efeitos dos fármacos , Streptococcus thermophilus/crescimento & desenvolvimento
5.
Ideggyogy Sz ; 68(7-8): 229-42, 2015 Jul 30.
Artigo em Húngaro | MEDLINE | ID: mdl-26380417

RESUMO

Although still a controversial management option, radio-surgery of intracranial cavernomas has become increasingly popular world-wide during the last decade. Microsurgery is a safe and effective treatment for symptomatic hemispheric cavernomas. However, the indication for microsurgical resection of deep eloquent cavernomas is relatively limited even in experienced hands. The importance of radiosurgery has recently been appreciated in parallel with increasing positive experiences both in terms of effectiveness and safety, especially for cases high risk for surgical resection, in the brainstem, thalamus and basal ganglia. While radiosurgery was earlier indicated mainly for surgically inaccessible lesions that had bled multiple times, a more proactive policy has recently become more accepted. In our opinion preventive treatment with the low morbidity radiosurgery serves the patients' interest especially for deep eloquent lesions that had bled not more than once, due to the cumulative morbidity of repeated hemorrhages. Despite our increasing knowledge on natural history, there is currently no available treatment algorithm for cavernomas. Arguments for all three treatment modalities (observation, microsurgery and radiosurgery) are established, but their indication criteria are yet to be defined. It is time to organize a prospective population based data collection in Hungary, which appears to be the most realistic way to clarify indication criteria.


Assuntos
Neoplasias Encefálicas/cirurgia , Hemangioma Cavernoso do Sistema Nervoso Central/cirurgia , Radiocirurgia/tendências , Gânglios da Base/cirurgia , Perda Sanguínea Cirúrgica , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/mortalidade , Tronco Encefálico/cirurgia , Área de Broca/cirurgia , Epilepsia/etiologia , Hemangioma Cavernoso do Sistema Nervoso Central/complicações , Hemangioma Cavernoso do Sistema Nervoso Central/mortalidade , Humanos , Internacionalidade , Microcirurgia , Procedimentos Neurocirúrgicos , Seleção de Pacientes , Radiocirurgia/efeitos adversos , Radiocirurgia/normas , Tálamo/cirurgia , Resultado do Tratamento , Conduta Expectante
6.
Ideggyogy Sz ; 68(7-8): 243-51, 2015 Jul 30.
Artigo em Húngaro | MEDLINE | ID: mdl-26380418

RESUMO

BACKGROUND AND PURPOSE: Radiosurgery is an increasingly popular treatment option especially for deep eloquent intracerebral cavernomas that are often too risky for surgical removal, but their re-bleed carries significant risk for persisting neurological deficit. Gamma-radiation based radiosurgery has been being available since 2007 in Hungary in Debrecen. Our aim is to summarize our experience accumulated during the first five years of treatment and to compare it to the international experience. PATIENT SELECTION AND METHODS: We retrospectively analyzed 51 cavernomas in 45 patients treated between 2008 and 2012 in terms of localization, natural history, and the effect of radiosurgery on re-bleed risk and epilepsy, and its side effects. RESULTS: We treated 26.5% deep eloquent (brainstem, thalamic/basal ganglia) and 72.5% superficial hemispheric cavernomas. The median presentation age was 25 years (13-60) for deep, and 45 years (6-67) for superficial cavernomas. They were treated median of 1 year after presentation. 64.5% of deep cavernomas bled before treatment, the annual risk of first hemorrhage was 2%/lesion, re-bleed risk 21.7%, with 44% persisting morbidity. 13.5% of superficial cavernomas bled prior to treatment, the risk of first bleed was 0.3%, there was no re-bleed, and 35% caused epilepsy. We used GammaART-6000TM rotating gamma system for treatment, marginal dose was 14 Gy (10-16), and treatment volume 1.38-1.53 cm3. Re-bleed risk of deep eloquent lesions fell to 4% during the first two years after treatment and to 0% thereafter, and no hemorrhage occurred from superficial lesions after treatment. Persisting morbidity in deep lesions came from adverse radiation effect in 7% and from re-bleed in 7%, and there was no persisting side effect in superficial cavernomas. 87.5% of cases of epilepsy resistant to medical therapy improved. Radiological regression was found in 37.5% and progression in 2% after treatment. CONCLUSIONS: Radiosurgery of cavernomas is safe and effective. Early preventive treatment for deep cavernomas carrying high surgical risk is justified. Moreover, for superficial lesions that are surgically easily accessible radiosurgery also appears to be an attractive alternative.


Assuntos
Neoplasias Encefálicas/cirurgia , Hemangioma Cavernoso do Sistema Nervoso Central/cirurgia , Radiocirurgia/tendências , Adolescente , Adulto , Idoso , Gânglios da Base/cirurgia , Neoplasias Encefálicas/complicações , Neoplasias Encefálicas/mortalidade , Tronco Encefálico/cirurgia , Área de Broca/cirurgia , Hemorragia Cerebral/etiologia , Criança , Epilepsia/etiologia , Feminino , Hemangioma Cavernoso do Sistema Nervoso Central/complicações , Hemangioma Cavernoso do Sistema Nervoso Central/mortalidade , Humanos , Hungria , Masculino , Pessoa de Meia-Idade , Seleção de Pacientes , Radiocirurgia/efeitos adversos , Radiocirurgia/instrumentação , Recidiva , Estudos Retrospectivos , Tálamo/cirurgia , Resultado do Tratamento
7.
J Trace Elem Med Biol ; 30: 160-70, 2015 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-25604949

RESUMO

PROJECT: Beside its useful functions at very low concentrations, selenium including supplementary Se sources pose a potential toxicological risk. The toxicity of selenium species was tested in HaCaT cell culture and related nephrotoxicity in mice. PROCEDURE: The apoptotic shrinkage and necrotic expansion of cells were measured by time-lapse image microscopy. Acute nephrotoxicity was estimated upon administration of various selenium species to mice for two weeks. To confirm or to refute the accumulation of Se in the kidney and its potential chronic effect, Se concentration in kidney tissue and histopathlology were tested. RESULTS: The comparison of selenium species showed that organic lactomicroSe did not affect cell growth at 5ppm, but inorganic nanoSe severely hampered it at lower concentration (1ppm). The in vivo Se treatment (0.5, 5, 50ppm, corresponding to 4, 40 and 400µg/kg) was misleading as it did neither affect the outward appearance nor the weight of the kidney. Se accumulation was observed after selenate, selenite, SelPlex, selenite and nanoSe administration, while lactomicroSe caused no traceable accumulation. In vivo, ex vivo and in vitro experiments reflected this order of selenium toxicity: selenate>selenite>SelPlex=nanoSe>lactomicroSe. CONCLUSION: Within the tested species lactomicroSe was the only non-nephrotoxic selenium source recommended for nutritional Se supplementation.


Assuntos
Queratinócitos/patologia , Rim/patologia , Selênio/toxicidade , Animais , Linhagem Celular , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Humanos , Absorção Intestinal/efeitos dos fármacos , Queratinócitos/efeitos dos fármacos , Rim/efeitos dos fármacos , Masculino , Camundongos , Microscopia de Vídeo , Nanopartículas/toxicidade , Nanopartículas/ultraestrutura , Compostos de Selênio/toxicidade , Coloração e Rotulagem , Imagem com Lapso de Tempo , Testes de Toxicidade Aguda
8.
J Sci Food Agric ; 93(9): 2221-8, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23349056

RESUMO

BACKGROUND: Fungal siderophores are likely to possess atheroprotective effects in humans, and therefore studies are needed to develop siderophore-rich food additives or functional foods to increase the siderophore uptake in people prone to cardiovascular diseases. In this study the siderophore contents of mould-ripened cheeses and meat products were analysed and the coprogen production by Penicillium nalgiovense was characterised. RESULTS: High concentrations of hexadentate fungal siderophores were detected in penicillia-ripened Camembert- and Roquefort-type cheeses and also in some sausages. In one sausage fermented by P. nalgiovense, the siderophore content was comparable to those found in cheeses. Penicillium nalgiovense produced high concentrations of coprogen in submerged cultures, which were affected predominantly by the available carbon and nitrogen sources under iron starvation. Considerable coprogen yields were still detectable in the presence of iron when the fermentation medium was supplemented with the iron chelator Na2-EDTA or when P. nalgiovense was co-cultivated with Saccharomyces cerevisiae. CONCLUSION: These data may be exploitable in the future development of high-siderophore-content foods and/or food additives. Nevertheless, the use of P. nalgiovense fermentation broths for these purposes may be limited by the instability of coprogen in fermentation media and by the ß-lactam production by the fungus.


Assuntos
Aditivos Alimentares/metabolismo , Ácidos Hidroxâmicos/metabolismo , Quelantes de Ferro/metabolismo , Penicillium/metabolismo , Sideróforos/biossíntese , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Doenças Cardiovasculares/prevenção & controle , Linhagem Celular , Sobrevivência Celular , Queijo/análise , Queijo/microbiologia , Cloretos/antagonistas & inibidores , Cloretos/metabolismo , Técnicas de Cocultura , Meios de Cultivo Condicionados/análise , Meios de Cultivo Condicionados/farmacologia , Fermentação , Compostos Férricos/antagonistas & inibidores , Compostos Férricos/metabolismo , Aditivos Alimentares/análise , Alimentos em Conserva/análise , Alimentos em Conserva/microbiologia , Alimento Funcional/análise , Alimento Funcional/microbiologia , Humanos , Hungria , Ácidos Hidroxâmicos/análise , Quelantes de Ferro/análise , Quelantes de Ferro/química , Queratinócitos/efeitos dos fármacos , Produtos da Carne/análise , Produtos da Carne/microbiologia , Micologia/métodos , Penicillium/química , Penicillium/crescimento & desenvolvimento , Saccharomyces cerevisiae/crescimento & desenvolvimento , Saccharomyces cerevisiae/metabolismo , Sideróforos/análise
9.
Environ Toxicol Chem ; 31(12): 2812-20, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22927138

RESUMO

Sixteen groups of mice were fed diets containing different selenium species to compare their toxicity. Inorganic sodium selenate and sodium hydroselenite, elementary nanoSe, organic Sel-Plex, and Lacto-MicroSelenium were administered for 14 d at concentrations of 0.5, 5, and 50 ppm Se, equivalent to 0.5, 5, and 50 mg Se/kg food, corresponding to an estimated 4, 40, and 400 µg/kg body weight/d Se uptake, respectively. At the end of the treatment, body, liver, spleen, kidney, heart, and brain weights were measured, mice were subjected to necropsy, and histological examinations were performed on the liver. At lower Se doses (0.5 and 5 ppm) a moderate reduction was observed in the number of bone marrow and white blood cells and in granulocyte-macrophage colony-forming units (GM-CFUs) relative to the untreated control group of mice. A comparison of lowest toxic doses of sodium selenite in mice (0.5 ppm) and mallard (10 ppm) indicates that birds are more resistant to Se than rodents. In mice, a small but measurable weight loss was observed after 5 ppm selenate and LactoMicroSe treatment. The most significant changes took place after 50-ppm administration in body and spleen weight, hematology, and liver histology. Toxicity was more pronounced when inorganic Se was applied than after subacute application of Sel-Plex, nanoSe, or LactoMicroSe. To summarize the effects, the authors' 14-d murine subacute toxicity study showed that the toxicity of Se species decreased in the following order: selenate > selenite > nanoSe > Sel-Plex > LactoMicroSe.


Assuntos
Poluentes Ambientais/toxicidade , Nanopartículas/toxicidade , Compostos de Selênio/toxicidade , Selênio/toxicidade , Animais , Peso Corporal , Dieta , Fígado/efeitos dos fármacos , Fígado/patologia , Masculino , Camundongos , Ácido Selênico , Selenito de Sódio/toxicidade , Baço/efeitos dos fármacos , Baço/patologia
10.
Acta Pharm Hung ; 77(1): 37-45, 2007.
Artigo em Húngaro | MEDLINE | ID: mdl-17518111

RESUMO

Comparative studies on the volatile and non-volatile fractions of 6 species. i.e. Salvia officinalis, S. tomentosa, S. fruticosa, S. candelabrum, S. ringens, S. lavandulifolia of the Section Salvia (Lamiaceae) have been carried out. Both fractions provide the chemical pattern matches to the chemotaxonomic character of Subfamily Nepetoideae in Erdtmanr two subfamiliar system. S. lavandulifolia had the highest essential oil content, followed by S. fruticosa, S. tomentosa, S. officinalis and S. candelabrum. S. ringens contains volatile oil only in traces. The neurotoxin thujone content was the highest in the S. officinalis oils and in that of S. fruticosa. No thujone was detected in S. lavandulifolia. The other species, e.g.: S. tomentosa contain this compound only in moderate concentrations (less than 10%). Among the non-volatile fractions of the plant ingredients the triterpene ursolic and oleanolic acids had the highest concentration in the leaves. Despite some rare cases, ursolic acid dominates the tritepene fraction. Rosmarinic and caffeic acids were measured in similar concentrations, in all species. As the case of S. officinalis shows, these compounds vary significantly in all organs during the vegetation period. Caffeic acid is also ubiquitous in the genus Salvia but as our data suggest it occurs in an order of magnitude lower concentration than rosmarinic acid. The isolation of phenylethanolid martynoside, though obtained in a rather small concentration, is of great chemotaxonomic significance, as this is the first phenylethanolid type glycoside isolated not only from the Salvia genus but also from the entire Subfamily Nepetoideae. As pheylethanolids are rather common and accumulate in significant concentrations in plants of the Subfamily Lamioideae, our opinion that the chemical differences between the two subfamilies are less qualititative than quantitative, is confirmed. This holds true of other chemical markers like monoterpenes, ursolic and oleanolic acids, caffeic acid and now phenylethanolids. Diterpenes i.e. 7-methyl carnosoate, rosmanol 7- methylether, sageon from S. officinalis, 7alpha-acetoyroyleanone, 7alpha-hydroxyroyleanone, royleanone, 6,7-dehydroroyleanone from S. tomentosa and candesalvoquinone, candelabroquinone, 12-O-methylcandesalvone, candesalvone B methyl ester and candelabrone have been isolated from Salvia candelabrum. All of the compounds belong to the abietane type of diterpenoids and have pronounced antioxidant effect.


Assuntos
Extratos Vegetais/química , Salvia officinalis/genética , Salvia/genética , Variação Genética , Fitosteróis/química , Fitosteróis/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Salvia/classificação , Especificidade da Espécie , Terpenos/química , Terpenos/isolamento & purificação
11.
J Nutr ; 135(11): 2530-4, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16251606

RESUMO

Insufficient ascorbate intake causes scurvy in certain species. Beyond its known functions, it has been suggested that ascorbate participates in oxidative protein folding in the endoplasmic reticulum (ER). Because redox imbalance in this organelle might cause ER stress and apoptosis, we hypothesized that this might contribute to the pathology of scurvy. Guinea pigs were divided into 7 groups: the control group was fed a commercial guinea pig food containing 0.1 g/100 g ascorbate for 4 wk, 5 groups consumed an ascorbate-free food for 0, 1, 2, 3, or 4 wk and 1 group was fed this scorbutic diet for 2 wk and then the commercial food plus 1 g/L ascorbate in drinking water for 2 wk. TBARS generation and the expression of some ER chaperones and foldases were determined in hepatic microsomes. The apoptotic index was assessed in histological sections. Although ascorbate, measured by HPLC, was undetectable in the livers of the guinea pigs after they had consumed the scorbutic diet for 2 wk, the microsomal TBARS level was elevated relative to the initial value only at wk 4. Western blot revealed the induction of GRP78, GRP94, and protein disulfide isomerase at wk 3 and 4. Apoptosis was greater than in the control, beginning at wk 3. None of the alterations occurred in the groups fed the commercial guinea pig food or ascorbate-free food followed by ascorbate supplementation. Therefore, persistent ascorbate deficiency leads to ER stress, unfolded protein response, and apoptosis in the liver, suggesting that insufficient protein processing participates in the pathology of scurvy.


Assuntos
Apoptose , Retículo Endoplasmático/patologia , Fígado/patologia , Escorbuto/patologia , Animais , Ácido Ascórbico/análise , Western Blotting , Peso Corporal , Retículo Endoplasmático/fisiologia , Chaperona BiP do Retículo Endoplasmático , Cobaias , Proteínas de Choque Térmico/análise , Fígado/química , Masculino , Glicoproteínas de Membrana/análise , Microssomos Hepáticos/química , Chaperonas Moleculares/análise , Tamanho do Órgão , Proteínas/análise , Substâncias Reativas com Ácido Tiobarbitúrico/análise
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