Quantitative microscopy of enzyme reactions in tissue sections.

Microdensitometry makes it possible to measure reaction products in discrete regions of tissue sections. Single cells, or groups of cells, can be selected for measurement. In this way, it is possible to obtain quantitative data from enzyme reactions, and to relate activities to histology. Some examples are given to illustrate the application of this technique.     

A loop for the transfer of thin tissue sections

The construction and use of a simple wire loop for the transfer of thin tissue sections are described. The loop picks up, carries, and releases a drop of liquid containing the sections. The loop is opened and closed by manipulation of the forceps to which it is attached. This controls the attraction of the loop for the water drop and ensures reliable pickup and release of the sections.     

A note on Aherne's method of counting tissue components in relatively thick sections

A convenient method is described for the routine collection of flat large-area sections for electron microscopy. The technique, which is of general application, has been applied to a survey of the dimensions and location of selected axons within a whole nerve.     

A simple method to obtain en face sections of flat tissue culture cells

A method is described for embedment of multiple confluent sheets of flat tissue culture cells that permits sectioning for thin or semithin sections in precise planes. The technique is especially useful for obtaining en face sections.     

Phosphorus standards for the electron probe X-ray microanalysis of ultrathin tissue sections

Phosphorus-containing standards for use during quantitative electron probe X-rays microanalysis of ultrathin tissue sections can be quickly and simply prepared using organo-phosphorus compounds which are soluble in Spurr's epoxy resin mixture. Trials of five such compounds (one solid, the rest liquid) are described.     

Tungsten coating--a method of improving glass microtome knives for cutting ultrathin sections.

Glass knives for ultramicrotomy were considerably improved by coating the cutting edge with a film of evaporated tungsten metal. Knives treated by this method gave up to tem times as many acceptable sections as uncoated glass knives. They could also cut thinner sections and harder tissues than ordinary glass knives, and eliminated some of the cutting artefacts produced by them. No explanation for this improvement was found although several possibilities were examined.     

Thin sections for hard tissue histology: a new procedure

We describe a simple method by which thin sections (∼100 µm) from modern and archaeological teeth and bones can be obtained. A detailed embedding–cutting–mounting procedure is proposed, suggesting the use of a dental adhesive system, composite resins and conventional embedding resins, with the aims of improving the quality of the sections and substantially reducing the steps and time needed to prepare specimens for histological analysis. The introduction of this dental materials-based system allows an accurate positioning of the sample embedded inside the resin, prevents cracks and distortions of the section during the cutting phase and generally improves mounting sections on slides.     

Staining methods for the detection of laticifers in plant tissue

Simple, easy and inexpensive methods have been evolved to detect laticifers in plants with the help of bright-field and fluorescence microscopy using Oil Red O, dansyl chloride, neutral red, Rhodamine B and Ponceau S stains.     

A new method for bearing design in the metal extrusion of profiled sections

The International Journal of Advanced Manufacturing Technology - Bearing design is a major issue in controlling material flow and producing high-quality extruded products. Adjusting the bearing...     

Intensity-based signal separation algorithm for accurate quantification of clustered centrosomes in tissue sections

Centrosomes are small organelles that organize the mitotic spindle during cell division and are also involved in cell shape and polarity. Within epithelial tumors, such as breast cancer, and some hematological tumors, centrosome abnormalities (CAs) are common, occur early in disease etiology, and correlate with chromosomal instability and disease stage. In situ quantification of CA by optical microscopy is hampered by overlap and clustering of these organelles, which appear as focal structures. CA has been frequently associated with Tp53 status in premalignant lesions and tumors. Here the authors described an approach to accurately quantify centrosome frequencies in tissue sections and tumors, independently of background or noise levels. Applying simple optical rules in nondeconvolved conventional 3D images of stained tissue sections, the authors showed that they could evaluate more accurately and rapidly centrosome frequencies than with traditional investigator-based visual analysis or threshold-based techniques. The resulting population-based frequency of centrosomes per nucleus could then be used to approximate the proportion of cells with CA in that same population. This was done by taking into account baseline centrosome amplification and proliferation rates measured in the tissue. Using this technique, the authors showed that 20-30% of cells have amplified centrosomes in Tp53 null mammary tumors.     

Digital image tiles: a method for the processing of large sections

Segmentation of large areas of light microscopic slides into N by N fields, and each of these fields into M digital image tiles, allows the scanning, storage and digital processing of large images. Any of the original N² fields or composites of M adjacent tiles can be recalled to the video display for analysis. Developed procedures for use on a microscope equipped with a precision scanning stage allow registration of the image coordinates (X-Y) for any original or composite field and the alignment of one of these fields along the depth (Z) axis by means of external, machined fiducial marks in serial sections. To facilitate work whenever unavoidable, we have incorporated methods for digital image panning and zooming (changes of magnification) and discuss their use and implications.