Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 72
Filtrar
Más filtros

Banco de datos
Tipo del documento
Intervalo de año de publicación
1.
J Histochem Cytochem ; 31(1A Suppl): 235-7, 1983 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-6186727

RESUMEN

The number, intracellular distribution, and staining characteristics of human hepatocellular peroxisomes that had been made visible by cytochemical staining for catalase were evaluated in biopsies from 75 patients with hepatic, inflammatory, or malignant disease and ten normal individuals. Intensity of staining was found to be proportional to enzymatic activity by microspectrophotometry. Scanning transmission electron microscopy (STEM) image analysis demonstrated an inverse relationship between peroxisomal size and contrast. Peroxisomes were more abundant, and often concentrated in a perinuclear configuration in cholestatic and cirrhotic livers. Decreased peroxisomal staining was common in cholestasis, cirrhosis, hepatitis, and in almost all patients with malignancies, both with and without hepatic metastases.


Asunto(s)
Hígado/ultraestructura , Microcuerpos/ultraestructura , Organoides/ultraestructura , Biopsia , Histocitoquímica , Humanos , Hígado/análisis , Microcuerpos/análisis , Microscopía Electrónica de Rastreo , Coloración y Etiquetado
2.
Clin Chim Acta ; 219(1-2): 79-91, 1993 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-8306466

RESUMEN

A sensitive method for the determination of the bismuth concentration in human serum is described. Analyses were carried out by inductively coupled plasma-mass spectrometry (ICP-MS), after a simple dilution of the samples with nitric acid. The detection limit of the applied method is 0.007 microgram/l whereas relative standard deviations varied from 5.7 to 13.6%. Determination of reference values in human serum of healthy adults gave a range from < 0.007 to 0.067 microgram/l (19 persons). Bismuth concentrations in serum were also measured before, during and after the intake of therapeutic doses of colloidal bismuth subcitrate (CBS). About 1.5-2 h after the intake of one tablet of CBS, the bismuth concentration in serum was found to have increased 51-1483 times (two apparently healthy volunteers and six hospitalized patients), showing that the serum bismuth concentrations can increase by several orders of magnitude during the intake of CBS. During the intake of four tablets of CBS per day by two apparently healthy volunteers, bismuth concentrations in serum after an overnight fast were found to be, respectively, 5.56 and 8.1 micrograms/l on day 15 and 4.28 and 13.6 micrograms/l on day 29. After stopping the therapy, the concentration of bismuth in serum slowly returned towards normal over a period of months.


Asunto(s)
Bismuto/sangre , Compuestos Organometálicos/farmacocinética , Adulto , Bismuto/farmacocinética , Coloides , Femenino , Liofilización , Humanos , Indicadores y Reactivos , Masculino , Espectrometría de Masas , Persona de Mediana Edad , Radioisótopos , Valores de Referencia , Comprimidos
3.
Talanta ; 29(11 Pt 2): 1029-34, 1982 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18963282

RESUMEN

A comprehensive review is given of how neutron-activation analysis for trace elements in biological matrices can be jeopardized by radiation damage, by the impurities present in the packing material or by nuclear interferences of major elements. Systematic errors during the counting process and the quantitative interpretation of the gamma-ray spectra should not be disregarded.

4.
Talanta ; 29(11 Pt 2): 973-84, 1982 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-18963275

RESUMEN

Trace-element levels estimated by different investigators are often disparate. It is becoming increasingly evident that sample contamination may explain some of the discrepancies. A method has been developed for the direct estimation of potential errors. This shows that extraneous additions occurring during sample collection and preparation may give rise to grossly misleading results on subsequent analysis.

5.
Talanta ; 37(8): 819-23, 1990 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-18965026

RESUMEN

Strontium has been determined in a human serum reference material by ICP-MS and by NAA. By ICP-MS, results for (88)Sr and (86)Sr in both 10- and 5-fold diluted serum were in good agreement. For (88)Sr the precision was better than 3% and the detection limit was 0.05 mug/l. under the conditions used. The results were 25.5 mug/l. in the liquid serum or 0.281 mug/g in the lyophilized reference material. In the NAA the (87m)Sr produced was radiochemically separated by extraction with oxine in chloroform. The precision was about 10% and the detection limit 0.02-0.05 mug/g.

6.
Clin Rheumatol ; 15(4): 410-3, 1996 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-8853179

RESUMEN

We report a case of biopsy-proven polyarteritis nodosa (classic type in association with the antiphospholipid syndrome. Medium-sized arteriopathy was confirmed on visceral angiography. Elevated anticardiolipin antibodies were detected before initiating therapy with methylprednisolone and IV pulse cyclophosphamide. Rapid subsidence of symptoms correlated with a gradual normalisation of the erythrocyte sedimentation rate. After 6 months of therapy anticardiolipin antibodies were within normal limits. Only one similar case has been reported so far.


Asunto(s)
Síndrome Antifosfolípido/diagnóstico , Poliarteritis Nudosa/diagnóstico , Angiografía , Síndrome Antifosfolípido/complicaciones , Síndrome Antifosfolípido/tratamiento farmacológico , Antirreumáticos/uso terapéutico , Biopsia , Ciclofosfamida/uso terapéutico , Glucocorticoides/uso terapéutico , Humanos , Masculino , Metilprednisolona/uso terapéutico , Persona de Mediana Edad , Poliarteritis Nudosa/complicaciones , Poliarteritis Nudosa/tratamiento farmacológico
7.
J Trace Elem Med Biol ; 9(4): 193-9, 1995 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-8808190

RESUMEN

A preliminary study was conducted on blood samples and blood fractions of 11 colorectal patients and 10 healthy subjects (controls) in Belgium, in order to determine the concentration of some vital trace elements. Two non destructive analytical methods were used for the determination: INAA and PIXE. The agreement between PIXE and INAA was within about +/- 10% for plasma, but for Rb, Se and Fe in whole blood and red cells a difference of +/- 20% was noted; part of the discrepancy may be due to self absorption problems in PIXE, and for Rb, spectral interferences also may have contributed. The precision of the INAA method for the elements studied was found to be +/- 3% for whole blood and red cells and +/- 5% for plasma; the accuracy for Br, Rb and Zn was better than +/- 10% and +/- 17% for Se. The ratios of the concentrations in whole blood to red cells and whole blood to plasma were not significantly different for normals and cancer cases and, therefore, in future studies analysis of whole blood only may be sufficient. The mean values for Br, Rb, Br/Rb ratio, K, Fe and Se were significantly lower for cancer cases than for healthy individuals, and this might be applicable as an additional parameter for differentiating normals from malignant cases.


Asunto(s)
Neoplasias Colorrectales/sangre , Análisis de Activación de Neutrones , Espectrometría por Rayos X , Oligoelementos/sangre , Anciano , Anciano de 80 o más Años , Bromo/sangre , Estudios de Casos y Controles , Femenino , Humanos , Hierro/sangre , Masculino , Persona de Mediana Edad , Potasio/sangre , Valor Predictivo de las Pruebas , Reproducibilidad de los Resultados , Rubidio/sangre , Selenio/sangre , Zinc/sangre
8.
Sci Total Environ ; 54: 217-30, 1986 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-3810128

RESUMEN

The lungs of eight individuals were investigated for 27 elements by neutron activation analysis and atomic absorption spectrometry. Thirteen segments of each lung pair were analyzed, together with hilar lymph nodes. The trace element distribution in the lungs and the inter-individual concentration differences reveal the existence of two groups of elements. A similar situation is observed in the lymph nodes. The elements Br, Cs, Cu, K, Na, Rb, Se and Zn are relatively homogeneously distributed over a lung pair and show little inter-individual concentration differences. On the other hand, Cd, Co, Cr, Pb, Sb, Sc and V are very inhomogeneosly distributed. The inhomogeneity and the concentrations increase with age. The existence of a concentration gradient within the lung and of relatively higher levels in the lymph nodes point to an enrichment in the lung tissue by inhaled atmospheric contaminants.


Asunto(s)
Pulmón/análisis , Oligoelementos/análisis , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Contaminantes Atmosféricos/análisis , Femenino , Humanos , Estilo de Vida , Ganglios Linfáticos/análisis , Masculino , Tráquea/análisis
9.
Biol Trace Elem Res ; 43-45: 407-13, 1994.
Artículo en Inglés | MEDLINE | ID: mdl-7710855

RESUMEN

Neutron activation analysis, in both its radiochemical and instrumental forms, is a precious technique for the determination of trace elements in biological materials. Probably its most important advantage is its relative freedom from errors resulting from contamination of the samples. Invaluable characteristics are also its excellent sensitivity, outstanding selectivity, and remarkable multielement capability. It is, however, necessary to warn against uncritical expectations. This is best illustrated by the seriously inconsistent results obtained in several laboratories. Because of the necessity to have access to a nuclear research reactor, the stringent safety rules to be observed, the rather high costs of the analyses, the relatively low sample throughput, and the sometimes long delay between the taking of a sample and the obtaining the final result, the use of neutron activation analysis remained restricted to a few--essentially research--laboratories. It found its main application in solving arduous problems and in paving the way for other analytical techniques better suited to routine applications.


Asunto(s)
Análisis de Activación de Neutrones , Oligoelementos/análisis , Animales , Humanos
10.
Biol Trace Elem Res ; 26-27: 529-40, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-1704759

RESUMEN

In order to help resolve present inconsistencies of two orders of magnitude or more in reported levels of vanadium in human serum and blood, a totally postirradiation radiochemical neutron activation analysis (NAA) method was further developed and applied to some pertinent nanogram and subnanogram reference materials. In particular, the second generation human serum reference material of Versieck was found to contain a value of 0.67 +/- 0.05 ng/g dry wt., corresponding to 0.061 +/- 0.005 /4/ ng/mL original fresh serum. Results are also reported for some other appropriate CRMs. Additionally, a small-scale study in 10 normal subjects (5 m, 5 f) revealed levels similar to those in the serum reference material and in agreement with the lowest data reported in the literature. Discussion of pitfalls of vanadium determination and the use of reference materials is included.


Asunto(s)
Análisis de Activación de Neutrones/métodos , Vanadio/sangre , Adulto , Estudios de Evaluación como Asunto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Análisis de Activación de Neutrones/normas , Estándares de Referencia , Valores de Referencia , Vanadio/normas
11.
Biol Trace Elem Res ; 26-27: 553-60, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-1704762

RESUMEN

The determination of trace and ultratrace elements in human serum by ICP-MS is described. The accuracy of the method is tested using a "second generation" human serum reference material. Elements determined include Fe, Co, Cu, Zn, Br, Rb, Sr, Mo, and Cs. The method is compared to nuclear analytical methods (NAA, PIXE). Perspectives for the future are also discussed.


Asunto(s)
Espectrometría de Masas/métodos , Oligoelementos/sangre , Estudios de Evaluación como Asunto , Humanos , Análisis de Activación de Neutrones , Estándares de Referencia , Valores de Referencia , Espectrometría por Rayos X , Oligoelementos/normas
12.
Biol Trace Elem Res ; 26-27: 683-9, 1990.
Artículo en Inglés | MEDLINE | ID: mdl-1704776

RESUMEN

A method is described for the determination of mercury in human blood serum and packed blood cells employing neutron activation analysis. Great attention was devoted to the collection and manipulation of the samples. The accuracy and precision of the method were tested by analyzing biological reference materials and by comparing the concentrations measured in a number of serum samples to those obtained by another, independent technique (cold vapor atomic absorption spectrometry) in the same samples. The article reports the levels measured in blood serum and packed blood cells samples from 15 adult volunteers, as well as the figures determined in a "second-generation" biological reference material (freeze-dried human serum), prepared and conditioned at the University of Ghent.


Asunto(s)
Análisis Químico de la Sangre/métodos , Eritrocitos/química , Mercurio/sangre , Análisis de Activación de Neutrones/métodos , Adulto , Análisis Químico de la Sangre/normas , Análisis Químico de la Sangre/estadística & datos numéricos , Humanos , Mercurio/normas , Análisis de Activación de Neutrones/normas , Análisis de Activación de Neutrones/estadística & datos numéricos , Estándares de Referencia , Valores de Referencia
13.
Biol Trace Elem Res ; 12(1): 45-54, 1987 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24254588

RESUMEN

Mounting evidence suggests that the accuracy of much of the published information on trace-element concentrations in biological matrices leaves much to be desired. Potential sources of error are: (a) inadequate sample collection and preparation (sampling errors); and (b) inaccuracies at the moment of the measurement (measurement errors). Probably much of what has been maintained on trace elements in human health and disease in the past will have to be revised in the future.

14.
Ned Tijdschr Geneeskd ; 139(51): 2658-61, 1995 Dec 23.
Artículo en Holandés | MEDLINE | ID: mdl-8569867

RESUMEN

In a 49-year-old man generalised argyria was diagnosed, a systemic dissemination and tissue deposition of silver in the body. The clinical picture was brought about by use of a silver acetate-containing lozenge as a deterrent to smoking. Argyria is characterised by a slate blue-gray discolouration of the skin, particularly in areas exposed to light. Generally, it causes patients a great deal of anguish and embarrassment. Present understanding is that it does not entail non-cutaneous, systemic effects. There is no effective treatment--the discolouration is permanent. Currently, prevention is the only possible measure. Efforts should be made to eliminate the uncontrolled use of silver-containing preparations.


Asunto(s)
Acetatos/efectos adversos , Cloruro de Amonio/efectos adversos , Argiria/etiología , Prevención del Hábito de Fumar , Ácido Acético , Argiria/sangre , Combinación de Medicamentos , Humanos , Masculino , Persona de Mediana Edad , Medicamentos sin Prescripción/efectos adversos , Plata/sangre
19.
Talanta ; 23(10): 745, 1976 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-18961977
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA