RESUMEN
Nuclear Magnetic Resonance (NMR) is of increasing diagnostic importance especially in human medicine. To evaluate possible side effects of this technology, embryonated chicken eggs were used as a model. Different fields (static magnetic field [1 oder 4 T], variable magnetic field [gradient] or high frequency field) were applied before the beginning and at the fifth day of incubation for different times (18.8, 37.6, 56 or 75.1 min, resp.). According to the criteria embryo-mortality, hatching-rate or vitality of the chickens, influences of the NMR-treatment were not observed.
Asunto(s)
Embrión de Pollo/efectos de la radiación , Campos Electromagnéticos , Espectroscopía de Resonancia Magnética/efectos adversos , Animales , Organismos Libres de Patógenos EspecíficosRESUMEN
Due to the different possibilities of image creation in MR tomography there is no clear terminology of pulse sequences and MR images. This paper tries to define the designation of pulse sequence parameters in a practical way and to specify the term "parameter weighting of MR images". Starting with general definitions, special definitions for CNS and liver are elaborated.
Asunto(s)
Espectroscopía de Resonancia Magnética , Sistema Nervioso Central/anatomía & histología , Humanos , Hígado/anatomía & histología , Espectroscopía de Resonancia Magnética/métodos , Terminología como Asunto , Factores de TiempoRESUMEN
Fading and recovery of Af-feulgen stained sperm heads are investigated at 73.5 K. The fast fluorescence signals are measured and stored by two coupled transient recorders. 100% recovery was reached after a dark time of 3 s. This shows that the photodecomposition is mainly caused by change of the probability density of energy level and not by destruction of the chromophore groups. The recovery effect allows measurement of the fluorescence intensity of the same sample more than 50 times. Therefore the unaffected spectrum can be measured directly, provided that between the short-term measurements at constant wavelength an appropriate dark phase has been put into operation.
Asunto(s)
Colorantes de Rosanilina , Espectrometría de Fluorescencia/métodos , Cabeza del Espermatozoide/análisis , Espermatozoides/análisis , Acriflavina , Animales , Bovinos , Frío , Colorantes , Fluorescencia , Colorantes Fluorescentes , MasculinoRESUMEN
The fluorometric behaviour of cellular objects is influenced during excitation by two nearly independent phenomena: (1) by the photochemical reaction of the DNA/AF dye complex, and (2) by the energy transfer among several DNA/AF dye complexes. Both processes show a distinct temperature-dependent behaviour and can therefore be characterized by the analysis of the fluorescence spectra at different temperatures. All microfluorometric measurements were performed with a self-constructed cooling device. The cryostat permits measurements of the cellular fluorescence within a range of temperatures between 4 K and 300 K. The cooling unit operates in accordance with the 'Continuous Flow Principle' and allows the application of objectives up to a numerical aperture of 0.6.
Asunto(s)
Acridinas , Acriflavina , ADN , Colorantes Fluorescentes , Fluorometría/métodos , Temperatura , Frío , Luz , Microscopía/instrumentación , Espectrometría de Fluorescencia/métodos , TermómetrosRESUMEN
The present methodological study is an attempt to optimize the staining parameters for a quantitative DNA determination of fluorescent cells. The application of pure dyes and a precise control of the staining procedure are preliminary conditions which have to be fulfilled, because the reproducibility of measurements is in this connection the most important criterion for a quantitative DNA related analysis of cell population. Chicken erythrocytes and isolated nuclei were applied as biological test objects. The staining procedure with acridine derivatives (acriflavine, proflavine, rivanol) was performed in accordance with the fluorescence-Feulgen reaction. The influence of staining parameters, such as (1) pH and (2) dye concentration of the staining solution, were evaluated regarding the spectral behaviour, the total fluorescence intensity, and the reproducibility of results.
Asunto(s)
Núcleo Celular/ultraestructura , ADN , Fluorescencia , Coloración y Etiquetado/métodos , Acriflavina , Animales , Núcleo Celular/fisiología , Pollos , Eritrocitos/ultraestructura , Colorantes Fluorescentes , Microscopía , Espectrometría de FluorescenciaAsunto(s)
Acridinas , Acriflavina , ADN/análisis , Proflavina , Espectrometría de Fluorescencia , Acriflavina/aislamiento & purificación , Acriflavina/metabolismo , Animales , Autoanálisis , Pollos , Cromatografía , ADN/metabolismo , Eritrocitos , Fotoquímica , Proflavina/aislamiento & purificación , Proflavina/metabolismoRESUMEN
A cryostat was constructed, which permits measurements of the intracellular fluorescence within a range of temperature between 3.5 to 300 K. The cooling unit operates in accordance with the "Continuous Flow Principle" and allows the application of objectives up to a numerical aperture of 0.6. It results from measurement of BAO Feulgen stained nuclear DNA, that a decrease of fluorescence intensity is caused by two different mechanisms: (1) There is a highly temperature dependent effect, originating from phenomena of solid physics, and (2) a second effect, which is almost temperature independent, and can be explained as a photochemical reaction.
Asunto(s)
Frío , Microscopía Fluorescente/instrumentación , Núcleo Celular/ultraestructura , ADN/análisis , Polen/ultraestructuraRESUMEN
A cooling chamber for microfluorometric measurement is described, which allows to cool under a microscope a biological sample till 77 K and to measure it with an objective of a numerical aperture 0.6. From first experiments with BAO (5)-stained Tradescantia pollen it can be concluded, that experiments in this range of temperature open new aspects regarding the interpretation of microfluorometric phenomena.