Search results for "Microscope"
showing 10 items of 1412 documents
Effect of the surface charge of liposomes on their uptake by angiogenic tumor vessels
2003
Recently, cationic liposomes have been shown to preferentially target the angiogenic endothelium of tumors. It was the aim of our study to investigate the influence of liposomal surface charge on the uptake and kinetics of liposomes into solid tumors and tumor vasculature. Experiments were performed in the amelanotic hamster melanoma A-Mel-3 growing in the dorsal skinfold chamber preparation of male Syrian golden hamsters. Fluorescently labeled liposomes with different surface charge were prepared. Accumulation of i.v. injected liposomes was assessed by quantitative intravital fluorescence microscopy of tumor and surrounding host tissue. The histological distribution of liposomes was analyz…
Metachromatic staining and electron dense reaction of glycosaminoglycans by means of Cuprolinic Blue
1987
The cationic phthalocyanin-like dye Cuprolinic Blue, unlike phthalocyanin dyes such as Alcian Blue or Astra Blue, can definitely exhibit a clear metachromatic reaction with appropriate substrates. The application of Cuprolinic Blue to epoxy-embedded semithin sections revealed that mast cell cytoplasmic granules, goblet cell mucin and cartilage matrix stained in violet shades (metachromatic), whereas nuclear chromatin presented a bright blue coloration (orthochromatic). The metachromatic structures showed a high degree of contrast when ultrathin sections treated with Cuprolinic Blue were examined by electron microscopy. Cytophotometric measurements of stained components from the large intest…
Inverse behaviour of "synaptic" ribbon and spherule numbers in the pineal gland of male guinea-pigs exposed to continuous illumination.
1986
There is increasing evidence that pineal “synaptic” ribbons are a heterogeneous population of organelles. In addition to “synaptic” ribbons (SR) sensu stricto, which consist of an electron-dense rod surrounded by electronlucent vesicles, “synaptic” spherules (SS) exist, the electrondense core of which is round and much wider than that of the SR. In the guinea-pig SR and SS numbers exhibit an inverse day/night rhythmicity. To gain more insight into the functional significance of SR and SS, guinea-pigs were exposed to continuous illumination for approximately 4 months (LL) and the respective structures in the pineal gland were quantitated under the electron microscope and compared with contro…
Spatially multiplexed interferometric microscopy with partially coherent illumination
2016
We have recently reported on a simple, low cost, and highly stable way to convert a standard microscope into a holographic one [Opt. Express 22, 14929 (2014)]. The method, named spatially multiplexed interferometric microscopy (SMIM), proposes an off-axis holographic architecture implemented onto a regular (nonholographic) microscope with minimum modifications: the use of coherent illumination and a properly placed and selected one-dimensional diffraction grating. In this contribution, we report on the implementation of partially (temporally reduced) coherent illumination in SMIM as a way to improve quantitative phase imaging. The use of low coherence sources forces the application of phase…
Spatial calibration of structured illumination fluorescence microscopy using capillary tissue phantoms.
2008
Quantitative assessment of microvascular structure is relevant to the investigations of ischemic injury, reparative angiogenesis and tumor revascularization. In light microscopy applications, thick tissue specimens are necessary to characterize microvascular networks; however, thick tissue leads to image distortions due to out-of-focus light. Structured illumination confocal microscopy is an optical sectioning technique that improves contrast and resolution by using a grid pattern to identify the plane-of-focus within the specimen. Because structured illumination can be applied to wide-field (nonscanning) microscopes, the microcirculation can be studied by sequential intravital and confocal…
Adaptation of the disector method to rare small organelles in TEM sections exemplified by counting synaptic bodies in the rat pineal gland
1997
The disector is the only objective method for quantifying particles of variable size in a given volume. With this method, cell organelles are identified on adjacent sections, but only those present in one section are counted. When counting extremely rare structures in transmission electron microscope sections (physical disector), the usual procedure of counting on electron micrographs is limited for economic reasons (e.g. micrographs highly outnumbering the investigated structures). Hence, to apply this unbiased stereological method, a modification of the physical disector concerning 3 aspects has been developed. (1) The prerequisite of screening large corresponding tissue areas (here appro…
Short-term response of three resin-based materials as desensitizing agents under oral environmental exposure
2012
Objective. This paper focuses on clinical responses after 7 days of oral exposure to two resin-based materials as desensitizing agents compared to a fluoride varnish and on morphological and analytical study as a means to elucidate the mechanism of action. Materials and methods. The elemental composition of Vertise™ Flow (VF), Universal Dentine Sealant (UDS) and Flor-Opal® Varnish (FOV) were investigated by using an X-ray energy dispersive spectrometer (EDX) in conjunction with a scanning electron microscope (SEM). SEM morphology of the material-treated dentine surfaces and pain reduction ability according to the Visual Analogue Scale (VAS) were evaluated in selected hypersensitive teeth. P…
Analysis of synaptic bodies in the Sprague–Dawley rat pineal gland under extreme photoperiods
2007
Synaptic bodies (SBs) are small, prominent organelles in pinealocytes, most probably involved in signal transduction processes. To check the influence of the photoperiod on their shape plasticity and number we chose two extreme lighting conditions, i.e. 20 h of illumination followed by 4 h of darkness (LD 20:4) versus (LD 4:20). Pineal glands were assessed at 0, 4 and 13 h after dark onset. Under both conditions reconstructed SBs were plates or ribbons but never spheres and there were no obvious differences in morphology. Photoperiodic changes in SB profile size and number were investigated: application of the established method for SB quantification based on single section profile counts (…
Strain differences in the ratio of synaptic body types in photoreceptors of the rat retina.
1993
In the retinal outer plexiform layer of seven different rat strains, synaptic bodies (SB) were counted and, according to their morphology, characterized as synaptic ribbons (SR), synaptic spheres (SS) or intermediate structures. It was found that absolute SB numbers showed relatively small variations while SR/SS ratios differed considerably between the strains investigated. These results are discussed with respect to retinal pigmentation and to formation and degradation, respectively, of synaptic ribbons.
Ultrastructural alterations and environmental exposure influence the opiate concentrations in hair of drug addicts
1995
Hair samples were taken at autopsy from the head of 1 male and 1 female subject both known as drug abusers. Some of the strands were bleached by in-vitro cosmetic treatment. The bleached hair as well as the original hair samples were partly exposed to water or soil prior to further investigations and drug monitoring. The exposure times were 4 weeks or 6 months for water and 6 months for soil. The hair fibers were examined by transmission electron microscope (TEM) and by scanning electron microscope (SEM) investigations. The electron microscope studies confirmed that all experimental conditions had produced morphological alterations in the hair fibers. After exposure to water or to soil for …