A Simpler and More Economical Method for Storing Glass Knives

A recently published paper (Schoenwolf 1982) suggested the use of modified microscope slide boxes to store glass knives routinely used for ultramicrotomy. Since the microscope slide boxes cost about $10.00, require modification and may damage the fragile cutting edge unless the knife is carefully oriented, Schoenwolf's method appears to be more expensive and cumbersome than the one used routinely in the authors' laboratory.     

Improved Methods for Making and Using Glass Knives

We have observed over time that the right side of a glass knife is the optimal cutting edge for microtomy if the counterpiece (heel opposite the edge) is controlled within 1 mm. The right cutting edge has been considered the “saw toothed” side and has not been used for ultrathin sectioning. We have observed that the right cutting edge is sharper and more durable than the left. Light and scanning electron microscopy were used to observe the cutting edge, and transmission electron microscopy was used to examine semithin and ultrathin sections of animal and plant tissues cut by the right and left sides of the cutting edge. The results indicate that the cutting edge becomes sharper and more durable from left to right. Both the quality and efficiency of ultrathin sectioning is improved by using the right cutting edge.     

Glass-Breaking Pliers for the Preparation of Glass Knives Used in Ultramicrotomy

Pliers used for handling plate glass customarily have flat jaws, but a modification in design of the jaws—one convex and the other concave—facilitates breaking small pieces of glass along a score mark. An index mark on the concave jaw is aligned with the score, and closure of the jaws limited to a proper width by an adjusting screw in the handle.     

Producing Improved Glass Knives for Ultra-Microtomy; A Glass Breaker Featuring a Linear Fulcrum and a Device for Controlling Fracturing Velocity

Innovations include: (1) interchangeable round linear fulcra of different diameters, (2) compressible materials covering pressure sites, and (3) a screw-compression mechanism for initiating breaks and controlling fracturing velocity. The instrument consists of a cross-shaped pressure plate hinged to a rectangular metal base bearing the pressure-applying mechanism opposite the hinge. A longitudinal slot in the pressure plate parallels the long axis of the fulcrum and permits positioning of prescored glass pieces or permits scoring of an engaged glass piece by guiding a scorer inserted through the slot. Knives with straight, flawless edges have been obtained from different types of glass (up to 7/16 inch thick) including soft, pyrex and tempered. Greater than 50% yield of useable knives averaging more than 50% of flawless edge, as judged at a magnification of 220 and by ultrathin sectioning, has been obtained with the device. The instrument design and technique facilitate controllably reducing the fracturing velocity to significantly increase the width of stress-free knife edge obtained. Details of the technique, optional attachments and modifications are outlined.     

Vitreous Carbon: A New Material for Making Microtome Knives

The quality of sections obtained by microtomy depends to a large extent on the quality and characteristics of the microtome knife itself. Despite the need for improved microtomy techniques, there have been few significant developments since the introduction of glass and diamond knives in the 1950's. The manufacture of microtome knives from vitreous carbon provides new possibilities for developing both improved methods and improved equipment for specimen sectioning. Vitreous carbon has unique physical properties that lend themselves to the generation of precision cutting edges. Such an edge can be obtained either by breaking a piece of vitreous carbon or by using lapidary techniques. The resultant edge seems well adapted to both thick and thin sectioning. The introduction of vitreous carbon as a sectioning tool offers a significant alternative to metal, glass and diamond knives.     

Science and Art in Preparing Tissues Embedded in Plastic for Light Microscopy, with Special Reference to Glycol Methacrylate, Glass Knives and Simple Stains

Plastic embedding preserves tissue structure much more faithfully than does paraffin. Acrylic polymerization is innocuous to dye-binding groups in sections. The water solubility of glycol methacrylate monomer and the hydrophilic properties of the polymer allow for convenience in dehydration and for versatility in staining sections. Five years of experience with glycol methacrylate (GMA) embedding for light microscopy is summarized. Methods for purifying GMA monomer are cited. Procedures for fixing, dehydrating, embedding, polymerizing, sectioning and staining, using GMA, are explained. A method is provided for making glass knives long enough to cut large blocks. Simple, reliable, quick staining methods are outlined. When compared with paraffin, GMA offers opportunities for simpler, quicker procedures and yields sections of superior quality, greater information content, and less distortion.     

Cody Knives and the Cody Complex in Plains Prehistory: A reassessment

Abstract

Discovery of the oldest dated Cody Knife in the New World calls for a redefinition of the Cody Complex in High Plains prehistqw. Its greater antiquity plus its association with an earlier culture gives new insight into the developmental sequence of certain Paleo-Indian tools.     

A Rapid and Economic In-House DNA Purification Method Using Glass Syringe Filters

Background

Purity, yield, speed and cost are important considerations in plasmid purification, but it is difficult to achieve all of these at the same time. Currently, there are many protocols and kits for DNA purification, however none maximize all four considerations.

Methodology/Principal Findings

We now describe a fast, efficient and economic in-house protocol for plasmid preparation using glass syringe filters. Plasmid yield and quality as determined by enzyme digestion and transfection efficiency were equivalent to the expensive commercial kits. Importantly, the time required for purification was much less than that required using a commercial kit.

Conclusions/Significance

This method provides DNA yield and quality similar to that obtained with commercial kits, but is more rapid and less costly.     

A Universal Glass Support for Oligonucleotide Synthesis

Abstract

A single type of controlled pore glass derivatized with 3-anisoyl-2′(3′)-O-benzoyluridine 5′-O-succinyl residues can be used as the support in solid phase syntheses of either oligoribo- or oligodeoxyribonucleotides.     

Alcian Blue Method for Attaching Glycol Methacrylate Bone Marrow Sections to Glass Slides

Detachment of glycol methacrylate sections from glass slides is a common problem during histochemical and immunohistochemical procedures, particularly when large or hard tissue sections are stained and when using caustic solutions, alcohols, or proteases.