A Method for Breaking Glass Knives Slowly

There is a general belief among electron microscopists that the speed of the break in forming the edge of a glass knife is of great importance in determining its quality. Slow breaks seem very desirable (Hayat 1970).     

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.     

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.     

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.     

一种便捷而经济的显微注射针填充方法

目的:建立一种便捷而经济的将DNA溶液填充至显微注射针的方法,以提高显微注射法转基因的效率。方法:将通常用于转移胚胎的口吸管稍加改进,吸取DNA溶液,从尾部直接注入显微注射针。结果:采用本方法填充显微注射针,可在2～5min完成DNA填充。结论:与传统方法相比,本法经济而高效,可加快显微注射法制作转基因动物的实验进程。     

一种简单、经济的植物RNA抽提方法

一种简单、经济的植物ＲＮＡ抽提方法孟玲谭德勇王焕效吕朝晖王晓燕周翔（云南大学生物系,昆明６５００９１）ＡＳｉｍｐｌｅＥｃｏｎｏｍｉｃａｌＭｅｔｈｏｄｆｏｒｔｈｅＩｓｏｌａｔｉｏｎｏｆＰｌａｎｔＲＮＡＭＥＮＧＬｉｎｇＴＡＮＤｅｙｏｎｇＷＡＮＧＨｕａｎｘ...     

一种简便经济的凝胶电泳同工酶特异染色方法

介绍一种简单、经济的同工酶染色方法：用熔化的0．4％琼脂糖处理滤纸备用,染色前将滤纸浸于同工酶染色液中,染色时将滤纸盖在聚丙烯酸胺胶上,然后将胶放在有盖塑料盒中保温染色,染色时间要比普通方法略长。染色后将胶和滤纸移入固定液中用镊子除去滤纸．     

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.     

A Simple and Economical Modification of the Masson-Fontana Method for Staining Melanin Granules and Enterochromaffin Cells

Enterochromaffin cells from the small intestine of man, guinea pig, dog, chicken, rabbit, cat and rat were stained using the Masson-Fontana ammoniacal silver method with varying dilutions of silver nitrate solution (0.25 to 5 g per 100 ml of distilled water) and incubation temperatures (60 C and 75 C). The 0.5% solution of silver nitrate gave an argentaffin pattern similar to that of the 5% solution and had two major advantages: economically, since much less silver nitrate is used, and methodologically, since low background resulted with tissue of those species (rat, cat and rabbit) that required unusually long incubation. The staining of melanocytes was similar for all dilutions at the usual staining time (15-30 min).     

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.     

Method for Storing Toxoplasma gondii (RH Strain) in Liquid Nitrogen

A simple method for storing the trophozoites of Toxoplasma gondii (RH strain) is described. Viability of the parasite was maintained for 160 days.     

A Much Convenient and Economical Method to Harvest a Great Number of Microglia

Microglia, implicating in such neuro-pathologies as brain inflammation, neurodegeneration, glioma, and neurogenesis, play an important role in central nervous system. Advanced research on microglia is crucial in exploring the neuro-pathology and neuro-physiology of these diseases, so how to culture large numbers of microglia in vitro becomes the base of a research. The wildly used method, at present, obtaining microglia from murine cannot fulfill the requirement of research, costing too much time and needing too many rats. We intend to introduce an optimized method that can harvest large quantities of microglia with high purity. Neonatal 2–3 days old Wistar rats were sacrificed and the cerebral cortices were trypsinized. We primarily cultured mixed cortical cells for 8–10 days. The microglia were harvested from the liquid supernatant; the left cells in the mixed cortical glial culture were passaged at a 1:2 density. After another 8–10 days of culture, microglia were collected again. And then, we passaged the left cells again for acquiring microglia from the third collection. We did not add additional mitogens in the experiment. At last, on average, 7.0 × 10⁶ microglia were collected from one neonatal rat. By this modified method, much more microglia can be effectively and easily harvested comparing with the usual protocol before. We compared the characteristics of microglia harvested from these three passages, such as morphology, phenotype, purity, and abilities on proliferation, secretion, and phagocytosis. The cells presented typical microglia morphology, having phenotype markers of CD11b/c and CD45. The microglia from these three passages retained similar phagocytosis and secretion functions. Expanded population of microglia for investigation can be provided by this easy method in a short time with little cost and few rats.