Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 33
Filtrar
1.
Food Chem Toxicol ; 101: 84-93, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-28065758

RESUMO

The aim of this study was to investigate if vitamin E (α-TOC) modulates the developmental toxicity of the pesticide endosulfan (ESF), using a modified zebrafish embryotoxicity test (ZET). Zebrafish (Danio rerio) embryos were exposed from 6 to 72 h post fertilization (hpf) to either ESF (0.1-50 mg/L) or α-TOC (0.01-3 mM) alone or in combination. The effects of these exposures on embryonic morphology, larval behavior and antioxidant gene expression were analyzed. Phenotypic analysis at 48 hpf showed that ESF led to a dose-dependent increase in embryonic deformities, including axis malformations, pericardial edema and reduced pigmentation. Co-exposure of ESF with α-TOC (1-3 mM) significantly (p < 0.05) reduced ESF-induced embryonic malformations. Exposure to solely α-TOC did not affect rates of survival or malformations. Behavior studies showed that ESF caused hyperactivity at 5 days post fertilization, indicating a developmental neurotoxic effect. The ESF-induced hyperactivity was ameliorated by α-TOC. Elevated ESF concentrations caused down-regulation of the antioxidant genes cuzn-sod, gpx1a and cat, suggesting that ESF promoted oxidative stress in the embryos. α-TOC did not prevent the ESF-induced dysregulation of these genes. These results demonstrate that α-TOC protects against phenotypic and behavioral effects caused by ESF but did not rescue ESF-induced aberrations in antioxidant gene expression.


Assuntos
Antioxidantes/farmacologia , Comportamento Animal/efeitos dos fármacos , Embrião não Mamífero/efeitos dos fármacos , Endossulfano/toxicidade , Vitamina E/farmacologia , Peixe-Zebra/crescimento & desenvolvimento , Animais , Embrião não Mamífero/patologia , Inseticidas/toxicidade , Estresse Oxidativo/efeitos dos fármacos
2.
Vet J ; 210: 77-81, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26975448

RESUMO

A randomised, double-blinded, placebo-controlled multicentre trial was conducted in 36 dogs with atopic dermatitis to evaluate the cyclosporine-sparing effect of polyunsaturated fatty acids. Dogs were stable on their individual cyclosporine dosage and received either a mainly omega-3 fatty acid product with a minor omega-6 fatty acid fraction or placebo, orally for 12 weeks. Dogs were examined every 4 weeks and the Canine Atopic Dermatitis Extent and Severity Index (CADESI-03) was determined by a clinician. Pruritus, quality of life, global condition and coat quality were scored by the owner. If the dog's CADESI-03 and/or pruritus score improved by at least 25% compared with the previous visit, the cyclosporine dosage was decreased by approximately 25%. If the scores deteriorated by at least 25%, the cyclosporine dosage was increased by the same percentage. The median daily cyclosporine dosage/kg bodyweight decreased in the active group from 4.1 mg to 2.6 mg and in the placebo group from 3.5 mg to 3.3 mg over the study period. The difference between the two groups was significant (P = 0.009). The improvement in median pruritus score from inclusion to completion was significantly greater in the active group than in the placebo group (P = 0.04). There was no significant difference in CADESI-03 changes between groups (P = 0.38). The results of this study indicate a cyclosporine-sparing effect of a mainly omega-3 fatty acid supplement in dogs with atopic dermatitis.


Assuntos
Ciclosporina/uso terapêutico , Dermatite Atópica/veterinária , Fármacos Dermatológicos/uso terapêutico , Doenças do Cão/tratamento farmacológico , Ácidos Graxos Ômega-6/uso terapêutico , Animais , Dermatite Atópica/tratamento farmacológico , Cães , Relação Dose-Resposta a Droga , Método Duplo-Cego , Interações Medicamentosas , Quimioterapia Combinada/veterinária , Feminino , Masculino
3.
J Thromb Haemost ; 14(1): 73-82, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26566785

RESUMO

UNLABELLED: Essentials The population prevalence of hereditary thrombotic thrombocytopenic purpura (TTP) is unknown. We studied the prevalence of hereditary TTP and population frequencies of two ADAMTS-13 mutations. A high frequency of hereditary TTP related to ADAMTS-13 mutation c.4143_4144dupA was found. Vicinity of ABO blood group and ADAMTS-13 loci may facilitate screening of ADAMTS-13 mutations. SUMMARY: Background Hereditary thrombotic thrombocytopenic purpura (TTP) caused by ADAMTS-13 mutations is a rare, but serious condition. The prevalence is unknown, but it seems to be high in Norway. Objectives To identify all patients with hereditary TTP in central Norway and to investigate the prevalence of hereditary TTP and the population frequencies of two common ADAMTS-13 mutations. Patients/Methods Patients were identified in a cross-sectional study within the Central Norway Health Region by means of three different search strategies. Frequencies of ADAMTS-13 mutations, c.4143_4144dupA and c.3178 C>T (p.R1060W), were investigated in a population-based cohort (500 alleles) and in healthy blood donors (2104 alleles) by taking advantage of the close neighborhood of the ADAMTS-13 and ABO blood group gene loci. The observed prevalence of hereditary TTP was compared with the rates of ADAMTS-13 mutation carriers in different geographical regions. Results We identified 11 families with hereditary TTP in central Norway during the 10-year study period. The prevalence of hereditary TTP in central Norway was 16.7 × 10(-6) persons. The most prevalent mutation was c.4143_4144dupA, accounting for two-thirds of disease causing alleles among patients and having an allelic frequency of 0.33% in the central, 0.10% in the western, and 0.04% in the southeastern Norwegian population. The allelic frequency of c.3178 C>T (p.R1060W) in the population was even higher (0.3-1%), but this mutation was infrequent among patients, with no homozygous cases. Conclusions We found a high prevalence of hereditary TTP in central Norway and an apparently different penetrance of ADAMTS-13 mutations.


Assuntos
Proteína ADAMTS13/genética , Púrpura Trombocitopênica Trombótica/epidemiologia , Adolescente , Adulto , Idoso , Alelos , Criança , Pré-Escolar , Estudos Transversais , Saúde da Família , Feminino , Frequência do Gene , Geografia , Homozigoto , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Mutação , Noruega/epidemiologia , Prevalência , Púrpura Trombocitopênica Trombótica/genética , Adulto Jovem
4.
J Appl Genet ; 50(2): 173-6, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19433916

RESUMO

The present study aimed at assessing the frequency of HFE mutations (C282Y, H63D and S65C) in western Romanian patients with liver disease of diverse aetiologies suspected of iron overload. A total of 21 patients, all Romanian residents hospitalized with clinical suspicion of iron overload and liver disease, were assayed for C282Y, H63D and S65C mutations, serum ferritin and viral hepatitis markers. Overall, 9 out of the 21 patients (42.86%) were found to harbour mutations in the HFE gene: 4 homozygotes C282Y (19.0%), 1 compound heterozygote C282Y/H63D (4.8%), 1 single heterozygote C282Y (4.8%), 2 single heterozygotes H63D (9.5%), 1 single heterozygote S65C (4.8%), and 12 wild-type cases (57.1%). Among the subgroup of 10 patients with the most prominent signs of iron overload (hyperferritinaemia and/or hepatocyte iron score > or = 1), without hepatocellular carcinoma, the HFE genotypes were conclusive in 5 cases (50%). They had significantly increased ferritin levels compared to wild-type cases (P = 0.029). The inclusion of iron studies during routine clinical visits, coupled with the availability of HFE genotyping for family and population studies, should facilitate the early detection of hereditary haemochromatosis in Romania.


Assuntos
Genótipo , Antígenos de Histocompatibilidade Classe I/genética , Sobrecarga de Ferro/genética , Hepatopatias/genética , Proteínas de Membrana/genética , Mutação , Adulto , Idoso , Feminino , Proteína da Hemocromatose , Humanos , Sobrecarga de Ferro/sangue , Sobrecarga de Ferro/etiologia , Hepatopatias/complicações , Masculino , Pessoa de Meia-Idade , Romênia
5.
J Comp Pathol ; 141(1): 27-40, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19344912

RESUMO

Seasonal iron overload in Svalbard reindeer was studied by light and electron microscopy and by X-ray microanalysis. The hepatic iron overload was of two types. The first type was characterized by massive siderosis of both parenchymal and non-parenchymal cells caused by a diet very rich in iron but low in energy and protein. Hepatocytes contained a moderate amount of free ferritin particles in the cytosol together with numerous siderosomes. This pattern is similar to that seen in primary haemochromatosis and thalassaemia. Kupffer cells contained large quantities of cytosolic ferritin, siderosomes and lysosomes with disintegrating red blood cells as seen in thalassaemia. The second type was characterized by massive non-parenchymal siderosis caused by an energy- and protein-poor diet with normal iron concentration. Hepatocytes contained little cytosolic ferritin and few siderosomes, but there were abundant electron-dense bodies without iron (i.e., autophagosomes). Kupffer cells were as described above. Ferritin was also present within the duodenal mucosa of these animals, located within enterocytes and lamina propria macrophages, as well as in the extracellular space and capillary and lacteal lumina. Ferritin was also present in the acinar cells of submucosal Brunner's glands. Changes consistent with exchange of ferritin particles between different cell types were observed. The role of ferritin as a possible iron transporter in this condition is discussed.


Assuntos
Duodeno/metabolismo , Sobrecarga de Ferro/metabolismo , Ferro/análise , Fígado/metabolismo , Rena/metabolismo , Animais , Dieta , Duodeno/química , Duodeno/ultraestrutura , Microanálise por Sonda Eletrônica , Feminino , Ferritinas/metabolismo , Ferritinas/ultraestrutura , Hepatócitos/química , Hepatócitos/metabolismo , Hepatócitos/ultraestrutura , Ferro/metabolismo , Células de Kupffer/química , Células de Kupffer/metabolismo , Células de Kupffer/ultraestrutura , Fígado/química , Fígado/ultraestrutura , Lisossomos/química , Lisossomos/metabolismo , Lisossomos/ultraestrutura , Masculino , Estações do Ano , Svalbard , Transferrina/análise
6.
Scand J Clin Lab Invest ; 67(6): 632-42, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17852835

RESUMO

The expression of delta 5 desaturase (D5D), delta 6 desaturase (D6D) and delta 9 desaturase (D9D) was determined by RT-PCR in the human promyelocytic cell line HL60. During 72 h of culture with 10% FBS, D5D and D6D were upregulated 5 to 6-fold, whereas D9D approximately doubled. The addition of fatty acids (FAs) to the culture medium suppressed upregulation of all desaturases. N-3 and n-6 FA appeared to be more effective than n-9 or saturated FA. When FAs were added after 72 h, further upregulation during the next 24 h was suppressed for nearly all desaturases and FAs tested, except for D5D when oleic acid (OA) or stearic acid (SA) was added. In cells cultured with restricted amounts of FBS, desaturase expression increased with decreasing concentrations of FBS. Cellular FA content decreased by 60% in the neutral lipid fraction, whereas that of the phospholipid fraction decreased by 10% during 72 h of culture. The largest decrease occurred in the sum of n-3 and n-6 FA of the neutral lipid fraction, which was reduced by 83%, whereas the content of these FAs in the phospholipid fraction decreased by 32%. The results indicate that when the supply of FA to HL60 cells is limited, the intracellular content of n-3 and n-6 FA decreases and this leads to upregulation of the desaturases, particularly D5D and D6D. Since HL60 cells resemble human leukocytes, the results suggest that desaturase expression in leukocytes may be exploited as a biomarker for FA status.


Assuntos
Gorduras Insaturadas na Dieta/sangue , Ácidos Graxos Dessaturases/metabolismo , Ácidos Graxos Insaturados/sangue , Regulação Enzimológica da Expressão Gênica , Células HL-60/enzimologia , Biomarcadores/sangue , Linhagem Celular , Dessaturase de Ácido Graxo Delta-5 , Gorduras Insaturadas na Dieta/farmacologia , Ácidos Graxos Dessaturases/efeitos dos fármacos , Ácidos Graxos Essenciais/sangue , Ácidos Graxos Essenciais/deficiência , Ácidos Graxos Essenciais/genética , Ácidos Graxos Insaturados/deficiência , Ácidos Graxos Insaturados/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Células HL-60/efeitos dos fármacos , Humanos , Linoleoil-CoA Desaturase/efeitos dos fármacos , Linoleoil-CoA Desaturase/metabolismo , RNA Mensageiro/análise , RNA Mensageiro/efeitos dos fármacos , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Estearoil-CoA Dessaturase/efeitos dos fármacos , Estearoil-CoA Dessaturase/metabolismo
7.
Scand J Gastroenterol ; 36(10): 1108-15, 2001 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11589387

RESUMO

BACKGROUND: Hereditary hemochromatosis (HH) is a common genetic disease leading to accumulation of iron in several organs, most notably the liver. The C282Y/C282Y mutation in the HFE gene is found in most cases. In order to prevent clinical disease and to study the cost and feasibility of screening, a large population was screened. METHODS: In a Norwegian county, all inhabitants 20 years or older were invited to participate in a population-based health survey programme. Screening for HH was one of several subprojects. Blood samples were obtained from 65,238 persons. Subjects with high serum transferrin saturation in two tests and high serum ferritin were clinically evaluated for HH. All subjects with high serum transferrin saturation in two tests were offered genotyping. RESULTS: HH was newly diagnosed in 92 women and 177 men. Phlebotomy treatment was performed in 64 women and 152 men. Severe organ damage (liver cirrhosis) was ascertained in only 4 men. We found no correlation between serum ferritin and age. The estimated cost was US$ 1.6 per subject screened and US$ 390 per newly discovered HH subject. The estimated prevalence of phenotypical HH not previously known was 0.34% in women and 0.68% in men. The prevalence of the C282Y/C282Y mutation was at least 0.68%. CONCLUSION: Large-scale screening for HH can be performed at a relatively low cost if combined with a health survey programme. The yield in terms of newly discovered cases is considerable, but few cases were found seriously ill. Better knowledge of the natural course of HH is necessary if we are to be able to estimate the cost-effectiveness of large-scale screening.


Assuntos
Hemocromatose/diagnóstico , Adulto , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Biópsia , Análise Custo-Benefício , Feminino , Ferritinas/análise , Hemocromatose/epidemiologia , Hemocromatose/genética , Humanos , Fígado/patologia , Cirrose Hepática/diagnóstico , Cirrose Hepática/patologia , Masculino , Programas de Rastreamento/economia , Programas de Rastreamento/métodos , Pessoa de Meia-Idade , Noruega/epidemiologia , Prevalência , Transferrina/análise
8.
J Midwifery Womens Health ; 45(5): 405-7, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11089359

RESUMO

Nonintervention in normal processes and promoting self-determination are both important aspects of midwifery philosophy and care; midwives are sometimes faced with situations in which these actually or potentially conflict. An example of this is epidural anesthesia, when the normal process of labor and birth may be affected by the woman's choices. This article focuses on an approach to this conflict that is essential to midwifery but often overlooked: the importance of trusting women to know what is best for themselves. The concept of trust in midwifery care is explored in depth, as a context from which to provide care, promote normal processes, ensure informed decision-making, empower women no matter what choices they make, and, when the woman's choice and midwife's philosophy differ, as a bridge from which to provide effective midwifery care.


Assuntos
Liberdade , Tocologia , Participação do Paciente , Comportamento de Escolha , Conflito Psicológico , Feminino , Humanos , Gravidez , Qualidade da Assistência à Saúde , Estados Unidos
10.
Genet Test ; 4(2): 147-9, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-10953954

RESUMO

In a previous hemochromatosis screening study including a total of 65,238 individuals, 566 persons were genotyped for the C282Y and the H63D mutations. Of these, a total of 433 samples (298 homozygous C282Y and 135 homozygous wild type) were reanalyzed to investigate if the potential presence of the newly described 5569G/A polymorphism had confounded the genotyping results for the C282Y mutation. Genotyping with a polymorphism-insensitive primer pair yielded no samples that altered their genotype. By utilizing the polymorphism-sensitive primer pair and elevated annealing temperatures, 133 samples previously genotyped as heterozygous C282Y were reanalyzed to verify the presence of the polymorphism in the population studied. Out of a total of 266 chromosomes, we found the polymorphism present in 9 chromosomes, yielding an allele frequency of 0.034 in this particular subpopulation. In one of the samples, the polymorphism was present on the same DNA strand as the C282Y mutation. We conclude that in the population studied, the 5569 G/A polymorphism is present, but its presence had no implications for the outcome of the previous genotyping. Nevertheless, we recommend that C282Y genotyping by restriction endonuclease digestion of PCR products in the future should utilize a primer pair that is not influenced by the 5569G/A polymorphism.


Assuntos
Testes Genéticos , Antígenos HLA/genética , Hemocromatose/genética , Antígenos de Histocompatibilidade Classe I/genética , Proteínas de Membrana , Polimorfismo Genético , Sequência de Bases , Primers do DNA , Feminino , Genótipo , Proteína da Hemocromatose , Heterozigoto , Homozigoto , Humanos , Masculino , Mutação Puntual
11.
J Midwifery Womens Health ; 45(6): 481-97, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11151462

RESUMO

As many as 25% of women experience bleeding in the first and early second trimester of pregnancy; about half of these will have a miscarriage or, more rarely, ectopic or molar pregnancy loss. This can be a difficult time for women because of the uncertainty of the outcome, lack of preventative measures, and emotional significance of early pregnancy loss. The qualities that characterize midwifery care, including providing complete information, encouraging self-determination, and being sensitive to the emotional state, are particularly important at this time. This article reviews the epidemiology; physiologic process; signs and symptoms of first trimester bleeding; miscarriage and other early pregnancy losses; and methods of clinical, biochemical, and sonographic evaluation. A framework to guide midwifery evaluation and management, based on confirmation of an intrauterine pregnancy followed by the determination of viability, is presented. Surgical, medical, and expectant management of nonviable pregnancy, management of viable pregnancy when bleeding persists, and follow-up care, including screening for psychological sequelae, are discussed. Case studies and specific clinical guidelines for midwifery care, consultation, collaboration, and referral are included. Understanding the emotional significance of first trimester bleeding and loss as a basis for sensitive care throughout the management process is addressed.


Assuntos
Aborto Espontâneo/enfermagem , Enfermeiros Obstétricos , Hemorragia Uterina/enfermagem , Aborto Espontâneo/epidemiologia , Aborto Espontâneo/psicologia , Dilatação e Curetagem/enfermagem , Feminino , Humanos , Mola Hidatiforme/epidemiologia , Mola Hidatiforme/enfermagem , Mola Hidatiforme/psicologia , Incidência , Gravidez , Complicações na Gravidez/enfermagem , Resultado da Gravidez , Primeiro Trimestre da Gravidez , Gravidez Ectópica/epidemiologia , Gravidez Ectópica/enfermagem , Gravidez Ectópica/psicologia , Fatores de Risco , Estresse Psicológico , Hemorragia Uterina/epidemiologia , Hemorragia Uterina/etiologia , Hemorragia Uterina/terapia
12.
Genet Test ; 4(4): 371-6, 2000.
Artigo em Inglês | MEDLINE | ID: mdl-11216661

RESUMO

In the present paper, we describe an individual, found as part of a screening study, being homozygous for the C282Y mutation and at the same time heterozygous for the H63D mutation in the HFE gene. Identical results were obtained by three different methods, i.e., by PCR-RFLP, by sequencing, and by melting curve analysis. Thus, the common conception that the C282Y and the H63D mutations are mutually exclusive is not valid. Clinical symptoms and laboratory data on the individual were similar to hemochromatosis patients homozygous for the C282Y mutation. The implications of our finding for diagnostic analytical laboratory procedures are briefly discussed.


Assuntos
Antígenos HLA/genética , Hemocromatose/genética , Antígenos de Histocompatibilidade Classe I/genética , Proteínas de Membrana , Mutação/genética , Adulto , Substituição de Aminoácidos/genética , Sequência de Bases , Análise Mutacional de DNA , Frequência do Gene , Hemocromatose/diagnóstico , Proteína da Hemocromatose , Heterozigoto , Homozigoto , Humanos , Masculino , Desnaturação de Ácido Nucleico , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , População Branca/genética
13.
Eur J Pediatr ; 156(1): 56-61, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9007493

RESUMO

UNLABELLED: There is no consensus regarding protein intake and the doses of recombinant human erythropoietin (r-HuEpo) and iron in the treatment of anaemia of prematurity (AOP). This open, randomized study has compared the effectiveness of 50 IU r-HuEpo/kg with that of 100 IU/kg, both given subcutaneously thrice weekly. In addition, two different protein supplements have been compared; lyophilized human milk protein and a commercial cow's milk product. Total protein intake was 3 g/kg per day. Daily iron dose was 18-36 mg. "Healthy" preterm infants (n = 32, birth weight: 800-1400 g, gestational age < or = 31 weeks) were studied from age 3 to 8 weeks. The two protein regimens yielded no differences in body growth, reticulocyte count or Hb concentration. In both r-HuEpo dose groups increased number of reticulocytes followed start of treatment; higher levels were, however, found in the group receiving 100 IU/kg. Mean Hb concentration plateaued at 12 g/dl for infants receiving 100 IU/kg, at 11 g/dl in the 50 IU/kg group. Even though serum levels of ferritin and transferrin saturation indicated no iron deficiency, soluble transferrin receptor increased in both groups, more rapidly and to higher levels in the 100 IU/kg group. In addition, the number of infants having more than 8% hypochromic red cells increased in both groups. CONCLUSIONS: Commercial cow's milk protein added to human milk was as good as human milk protein supplementation in supporting growth and erythropoiesis. Fifty IU/kg r-HuEpo thrice weekly during AOP stimulated erythropoiesis significantly, but less so than 100 IU/kg. Even when using high oral doses of iron to preterms receiving r-HuEpo, our data suggested a certain degree of iron deficient erythropoiesis.


Assuntos
Anemia Neonatal/terapia , Proteínas Alimentares/administração & dosagem , Eritropoetina/uso terapêutico , Recém-Nascido Prematuro , Ferro/uso terapêutico , Anemia Neonatal/prevenção & controle , Animais , Terapia Combinada , Eritropoese/fisiologia , Feminino , Crescimento/fisiologia , Hemoglobinas/metabolismo , Humanos , Fenômenos Fisiológicos da Nutrição do Lactente , Recém-Nascido , Ferro/sangue , Modelos Lineares , Modelos Logísticos , Masculino , Leite , Leite Humano , Receptores da Transferrina/sangue , Proteínas Recombinantes , Contagem de Reticulócitos
14.
Scand J Clin Lab Invest ; 56(7): 583-9, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8981653

RESUMO

The effect of illumination on intracellular free calcium concentration, [Ca2+]i, was studied in a cell line (WiDr cells) derived from a primary adenocarcinoma of the rectosigmoid colon. In these cells the biosynthesis of protoporphyrin IX was stimulated by 5-aminolevulinic acid to reach levels of 600-700 pmol of protoporphyrin IX per mg cell protein. A brief (1-min) exposure of the cells to light (70% of light energy at 340-380 nm) resulted in an increase in [Ca2+]i. This increase was not reversible over a period of at least 20 min following illumination. Elevation of [Ca2+]i most probably represented an influx of calcium ions from the medium to the cell, since it was completely abolished in the presence of extracellular EGTA. The increased [Ca2+]i did not reflect general membrane damage, as determined by trypan blue staining as well as measurement of the intercalation of ethidium bromide into cellular DNA, and neither did the sustained elevation of [Ca2+]i lead to any substantial loss of clonogenicity following illumination of protoporphyrin-containing cells. Together these results indicate that an increased [Ca2+]i level is not per se a cause of cell death during photodynamic therapy.


Assuntos
Ácido Aminolevulínico/farmacologia , Cálcio/metabolismo , Luz , Protoporfirinas/biossíntese , Adenocarcinoma/metabolismo , Neoplasias do Colo/metabolismo , Citosol/metabolismo , DNA/metabolismo , Ácido Egtázico/farmacologia , Corantes Fluorescentes , Fura-2 , Humanos , Células Tumorais Cultivadas
15.
Eur J Biochem ; 232(1): 129-33, 1995 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-7556141

RESUMO

The aim of the present study was to determine if human N-terminal half-transferrin (N- fragment), prepared by thermolysin cleavage of diferric transferrin, would bind to the rat hepatocyte transferrin receptor and donate iron to the cell. Competition experiments between 125I-labelled N-fragment and diferric transferrin revealed no receptor binding of the half-transferrin. Still, the N-fragment delivered iron to the cells in amounts approximately 30-fold above what could be accounted for by uptake of the fragment itself. The rate of cellular iron uptake from the fragment was comparable to what is seen with the intact transferrin. The uptake of 125I-labelled N-fragment was not inhibited by excess non-radioactive diferric transferrin. By comparison, the uptake of 59Fe from the N-fragment was inhibited 70% by excess nonradioactive diferric transferrin. This suggests that iron derived from diferric transferrin competes with the iron derived from the N-fragment for a common transport pathway. Although some cellular degradation of the N-fragment occurred, the extent of degradation was too low to explain the amount of iron accumulated by the cells. The results show that the hepatocyte has an effective transferrin-receptor-independent mechanism for accumulation of iron from transferrin.


Assuntos
Ferro/metabolismo , Fígado/metabolismo , Transferrina/metabolismo , Animais , Células Cultivadas , Humanos , Transporte de Íons , Masculino , Ensaio Radioligante , Ratos , Ratos Wistar , Receptores da Transferrina/metabolismo
16.
Biometals ; 8(1): 65-9, 1995 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-7865993

RESUMO

The lanthanide metal, gadolinium, is currently used in contrast agents for magnetic resonance imaging. We have performed a study of the interaction between isolated rat hepatocytes and 153Gd complexed to diethylene-triamine pentaacetic acid (DTPA) or to DTPA-albumin conjugates. The study shows that isolated hepatocytes are able to take up both types of 153Gd complexes. The 153Gd-DTPA-albumin complexes are apparently taken up by pinocytosis, and possibly receptor-mediated endocytosis and/or adsorptive endocytosis, whereas the uptake mechanism of 153Gd-DTPA is unknown. The 153Gd-DTPA-albumin complexes, but not the 153Gd-DTPA complex, are degraded by the cell. The degradation is inhibited by ammonium chloride. Gadolinium is slowly released back to the medium after loading of the cells with both complex types. In the experiments reported here no evidence of any adverse effects on the hepatocyte resulting from exposure to the 153Gd-complexes were observed.


Assuntos
Albuminas/metabolismo , Gadolínio/metabolismo , Fígado/metabolismo , Compostos Organometálicos/metabolismo , Ácido Pentético/análogos & derivados , Soroalbumina Bovina/metabolismo , Cloreto de Amônio/farmacologia , Animais , Transporte Biológico , Biotransformação , Células Cultivadas , Citosol/metabolismo , Gadolínio DTPA , Cinética , Fígado/efeitos dos fármacos , Compostos Organometálicos/farmacocinética , Ácido Pentético/metabolismo , Ácido Pentético/farmacocinética , Radioisótopos , Ratos
17.
Eur J Biochem ; 222(1): 105-12, 1994 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-8200334

RESUMO

In an attempt to improve our understanding of the complex interplay between cell compartments and chemical species during cellular uptake of iron from transferrin, we designed a computer simulation program based on current models of receptor-mediated endocytosis and pinocytosis. The program calculates and visualizes, as a function of time, the changes in transferrin, apotransferrin, and iron concentrations occurring in all relevant cellular compartments during cellular iron acquisition from transferrin. Simulation of literature data showed that the program generates results that are in accordance with experimental data. Furthermore, from measurements of the uptake of [carboxyl-14C]dextran we could utilize the program to suggest rate constants characteristic for the pinocytic process in rat reticulocytes. Moreover, simulations indicate that the apparent difference in the iron uptake process observed between reticulocytes and hepatocytes may be explained by the contribution made by pinocytosis to the iron uptake process. Finally, the present program should have potential as an educational tool during introduction to the field of receptor-mediated endocytosis in general and to cellular iron metabolism in particular.


Assuntos
Simulação por Computador , Ferro/metabolismo , Modelos Biológicos , Transferrina/metabolismo , Animais , Fígado/citologia , Fígado/metabolismo , Fígado/fisiologia , Masculino , Pinocitose , Ratos , Ratos Wistar , Software
18.
Tidsskr Nor Laegeforen ; 114(4): 446-9, 1994 Feb 10.
Artigo em Norueguês | MEDLINE | ID: mdl-8009482

RESUMO

Carbohydrate deficient transferrin has been proposed as an important marker for alcohol abuse. Using isoelectric focusing and two different radioimmunoassays we measured carbohydrate deficient transferrin throughout an alcohol withdrawal period in ten abusing men. Values within the normal range were found in two to four individuals, depending on the method. Nevertheless, carbohydrate deficient transferrin was more frequent pathologically (in two out of three methods) than any other of the common markers (glutamyl transferase, alanine transferase, aspartate transferase, mean corpuscular volume). During the withdrawal period, the carbohydrate deficient transferrin value increased in two patients after a new alcohol intake. However, it also increased on other occasions when a new alcohol intake was highly unlikely. Therefore, a single test or even repeated tests of carbohydrate deficient transferrin may give a wrong conclusion. Since the cost of the analysis is high, the clinical benefit should be evaluated more closely before the test is used in pure clinical settings.


Assuntos
Alcoolismo/sangue , Biomarcadores/análise , Carboidratos/análise , Transferrina/análise , Adulto , Alcoolismo/diagnóstico , Estudos de Avaliação como Assunto , Humanos , Focalização Isoelétrica , Masculino , Pessoa de Meia-Idade , Transferrina/química
19.
Scand J Clin Lab Invest Suppl ; 215: 113-20, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8327847

RESUMO

Transferrin receptors are present on almost all mammalian cells. The receptor participates in the cellular acquisition of iron from transferrin by receptor-mediated endocytosis. Receptor abundancy is generally regulated by two factors: i) cellular iron status and ii) cell growth. These two factors form the basis for the utilization of transferrin receptor determination as a diagnostic tool. In the assessment of body iron status and erythropoietic activity the measurement of circulating transferrin receptor has proved to be of value as a measure of mild tissue iron deficiency, to distinguish iron deficiency anemia from the anemias of chronic disease, and as a sensitive index of iron deficiency during pregnancy. Histochemical analysis of the presence and abundancy of the transferrin receptor will continue to serve as an additional tool in special cases to distinguish between malignant and normal cell growth, and to provide additional information about the biological behaviour of tumor cells. Finally, the transferrin receptor holds a potential as a target for direct and indirect drug delivery in the therapy of malignant cell growth.


Assuntos
Doenças Hematológicas/diagnóstico , Doenças Hematológicas/tratamento farmacológico , Neoplasias/diagnóstico , Neoplasias/tratamento farmacológico , Receptores da Transferrina , Portadores de Fármacos , Humanos , Receptores da Transferrina/análise , Receptores da Transferrina/metabolismo
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...