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At least 19 recordsLinked to original sources
PubMed1986

Direct visualization of microtomy artefacts in sections of twisted fibrous extracellular matrices.

Twisted fibrous extracellular matrices observed in section often show alternating clear and dark bands. Three different methods of observation (high voltage electron microscopy, shadowing of thin sections and stereoscopic views) show the presence of ruffling effects and relief at the surface of crab cuticle sections. These effects appear uneven on both sides of the sections. As shown in a series of diagrams, the localization of the microtomy artefact is a function of the orientation of the cuticle laminae relative to the knife direction, and this creates variations in the position and the extent of the microtomy effect over each lamina. Confirmation of this analysis is obtained in a particular geometrical situation which appears in sections of tubercles in the crab cuticle where the twisted plywood stratification is deformed into a dome. By shadowing thin sections, perpendicular to the tubercle axis, nested crescents are visualized on the surface of the samples. All observations demonstrate that the clear and dark lamellae are due to a microtomy artefact which is a three-dimensional process, and not, as usually considered, due to chemical or physical variations in the structure.

Animals↗
PubMed1994

Measurement of microtomy-induced section distortion and its correction for 3-dimensional histological reconstructions.

The presence of microtomy induced distortion in paraffin sections is a significant hindrance to the accurate alignment of sections for three-dimensional reconstructive techniques. Measurements of section distortion in various rat tissues demonstrated distortions to be present in all sections, with over 85% of such distortions being manifest as expansions when compared to the original distances between a series of eight drilled fiducial marks. Mean percentage dimensional changes in the direction of the cutting stroke and at right angles to this direction were -0.5 +/- 1.5% and 3.7 +/- 1.2% for liver, 7.6 +/- 2.4% and 9.1 +/- 1.2% for kidney, 6.6 +/- 2.3% and 10.5 +/- 1.4% for lung, and 20.3 +/- 6.6% and 8.9 +/- 5.9% for skeletal muscle. Individual sections invariably displayed measurable distortions, with only skeletal muscle showing any consistent pattern, in the form of "barrel" distortion at right angles to the cutting stroke. In addition a method of distortion correction and simultaneous image alignment is presented as a means of section alignment with full distortion correction capability. This method uses a quadratic polynomial transform in a non-linear "unwarping" algorithm, to correct for the rotational and translational misalignment as well as for microtomy and camera aspect ratio distortions. Application of this method to a sequence of 46 serial sections demonstrated an alignment accuracy to within 2.6 +/- 0.8 pixels.

Animals↗
PubMed1990

Hot knife microtomy for large area sectioning and combined light and electron microscopy in neuroanatomy and neuropathology.

The technical details given in this paper meet the demand in neuroanatomy and neuropathology for methods which combine broad light microscopical surveys with detailed ultrastructural studies of logically selected areas in well perfused brain material, and emerge directly from experiences in Palay's laboratory at the National Institutes of Health in 1956. Using the procedures recommended will give good sections of exceptionally large areas (up to, and above 1 cm x 1 cm) of fully hardened blocks available at all points for electron microscopy. On such large blocks fully correlative, combined light and electron microscopy may be carried out easily. The process is termed 'hot knife microtomy'. In three different laboratories, primary aldehyde fixation by perfusion and hot knife microtomy have given uniformly excellent data from normal, diseased, and virus-infected brain tissues. These techniques permit full neuroanatomical control and orientation, make comprehensive correlative mapping throughout the CNS feasible, and allow study of the time course of infective processes.

Animals↗
PubMed1990

Measuring the forces acting during microtomy by the use of load cells.

The forces acting upon the cutting blade during microtomy can be accurately measured by using a load cell. From the information obtained, the optimal knife angles (rake, clearance and slant) can be determined. In addition, the speed of cutting and thickness of sections can also be optimized. The information obtained from the load cell additionally reveals variations in tissue composition which affect the cutting forces. This paper is a preliminary communication to illustrate the possible roles for a modified microtome in (a) the study of microtomy and (b) comparative studies of tissue density.

Brain↗
PubMed1990

Modified embedding procedure for microtomy of large particle zeolites.

A method is described to strengthen the binding of organic resin to inorganic zeolite, allowing large particles to be microtomed. For FeZSM-5 aggregates the particle size limit increased from 3 microns to greater than 20 microns in diameter by application of this method. This technique can be applied to a variety of oxide powder samples, extending the utility of microtomy as a materials science tool.

Aluminum Silicates↗
PubMed1984

Interferometric analysis of intrasection and intersection thickness variability associated with cryostat microtomy.

Mach-Zehnder interferometric measurements were used to assess the extent of section thickness variability (inter- and intrasection) associated with cryostat microtomy of adrenal sections over a typical working range of 10-20 micron. Sections were obtained using a Bright's Cambridge rocking type and a Damon rotary type cryostat microtome to allow comparative analyses. The effective thickness of tissue sections after being mounted onto slides by flash drying was reduced by 90% relative to microtome section thickness setting. A linear relationship between measured thickness and microtome setting was obtained with both instruments. Thickness variability between replicate sections over the range of microtome settings approximated 11% for the rocking microtome and 5% with the rotary microtome. Average intrasection variability was found to be 7% for rocking microtome sections and 4% for sections obtained with the rotary microtome. However, this variability is a negligible source of error in cytophotometric analyses, providing replicate sections are used and an adequate number of measurements are made on mask-delimited individual cells or tissue specimen areas.

Adrenal Glands↗
PubMed1999

Celloidin-wax sandwich microtomy: a novel and rapid method for producing serial semithin sections.

A method is described that allows rapid and reliable serial sectioning down to thicknesses of 1 micron. The tissue is first embedded in celloidin and then in wax and trimmed so that the block is sandwiched between two layers of wax. This combines the virtues of both media. The celloidin gives greater support to tissue than wax and enables the cutting of semithin sections. The wax allows ribbons of serial sections to be produced as in conventional wax microtomy. This makes it easy to produce serial semithin sections as a matter of routine.

Animals↗
PubMed1993

Lumbar cribriform fascia: appearance at freezing microtomy and MR imaging.

Axial T1-weighted magnetic resonance (MR) images and exactly corresponding sections obtained with freezing microtomy of cadaveric lumbosacral spinal columns were compared to describe the MR appearance of the cribriform fascia within the neural foramen. On anatomic sections, the cribriform fascia was identified as a thin sheet of tissue in the lateral neural foramen. On MR images, the cribriform fascia appeared as a thin band of low signal intensity, which contrasted with the high-signal-intensity epidural fat. The cribriform fascia is another landmark in the neural foramen that can be identified with MR imaging.

Fascia↗
PubMed1988

The use of cryostat microtomy in a simplified Golgi method for staining vertebrate neurons.

The use of cryostat and cryoprotective measures for processing Golgi impregnated brain tissue has shortened and simplified the method without loss of quality. The procedure contains the following steps: (1) the animal is perfused with phosphate-buffered paraformaldehyde and the brain removed for storage in the fixative; (2) the brain is rinsed in buffer, cut into 3- to 6-mm-thick blocks and placed in Ramon-Moliner's impregnation solution for 2-4 weeks; (3) the brain tissue is cryoprotected by soaking in 30% sugar for 24 h and then frozen and cut on a cryostat, the sections, being collected directly on slides; and (4) the mounted sections are then alkalized, fixed, rinsed, counterstained and rinsed again before dehydration, clearing and coverslipping.

Animals↗
PubMed1958

Thin sections. I. A study of section thickness and physical distortion produced during microtomy.

Knowledge of the thickness of sections is important for proper interpretation of electron micrographs. Therefore, the thicknesses of sections of n-butyl methacrylate polymer were determined by ellipsometry, and correlated with the color shown in reflected light. The results are: gray, thinner than 60 mmicro; silver, 60 to 90 mmicro; gold, 90 to 150 mmicro; purple, 150 to 190 mmicro; blue, 190 to 240 mmicro; green, 240 to 280 mmicro; and yellow, 280 to 320 mmicro. These results agree well with optical theory and with previous published data for thin films. Sections, after cutting, are 30 to 40 per cent shorter than the face of the block from which they were cut. Only a small improvement results from allowing the sections to remain in the collecting trough at room temperature. Heating above room temperature, however, reduces this shortening, with a corresponding improvement in dimensions and spatial relationships in the sections. When the thickness of the section is considered in interpreting electron micrographs instead of considering the section to be two-dimensional, a more accurate interpretation is possible. The consideration of electron micrographs as arising from projections of many profiles from throughout the whole thickness of the section explains the apparent lack of continuity often observed in serial sections. It is believed that serial sections are actually continuous, but that the change in size of structure through the thickness of one section and the consideration of only the largest profile shown in the micrograph can account for the lack of continuity previously observed.

Histological Techniques↗