Holding plastic-embedded specimens for sectioning in a rotary microtome

Summary Three methods are evaluated for holding capsules of plastic-embedded tissue for rotary microtomy. Use of a V-block is rapid but deforms the capsule. Gluing the capsule to a supporting block is useful for reorientation of the capsule but otherwise time consuming. A metal adapter is easy to use, does not deform the tissue, and is the preferred method for routine microtomy.Supported in part by the U.S. Veterans Administration Hospital, Hines, Illinois.     

A holder for Ralph knives for cutting sections for high performance optical microscopy with a Minot type microtome

We present plans for an original holder for long-edged glass knives (Ralph knives). Knives are prepared by hand-breaking of commercial window glass (3 mm thick), for cutting large blocks of tissue embedded in a water-miscible plastic resin, glycol methacrylate.     

Magnetic resonance microscopy: in vivo sectioning of a developing insect

The utility of magnetic resonance imaging vis-a-vis insect morphology and development was investigated. MRI is a noninvasive technique that distinguishes between tissues based on proton content and proton 'environment'. At present a resolution of 100 micron is achievable. The technique avoids fixation artifacts and allows the detection of motion within the organism.     

Magnetic resonance microscopy: in vivo sectioning of a developing insect

Summary The utility of magnetic resonance imaging vis-a-vis insect morphology and development was investigated. MRI is a noninvasive technique that distinguishes between tissues based on proton content and proton environment. At present a resolution of 100 m is achievable. The technique avoids fixation artifacts and allows the detection of motion within the organism.     

Pentagastrin activation of adenylate cyclase in human gastric biopsy specimens.

Adenylate cyclase activity of human fundic mucosa is log-normally distributed and equally stimulated by pentagastrin and histamine. Cimetidine inhibits the histamine, but not the pentagastrin effect, which is even intensified by H2-receptor blockade. The results indicate that pentagastrin and histamine activate adenylate cyclase via distinct receptors.     

Media and methods for isolation of aeromonads from fecal specimens. A multilaboratory study

An international multilaboratory study was conducted to establish the optimal combination of culture media, incubation time and temperature for recovery of aeromonads from stools using blood ampicillin (10 mg/l) agar (BAA), starch ampicillin (10 mg/l) agar (SAA), and cefsulodin irgasan novobiocin agar (CIN) with alkaline peptone water (APW) for enrichment. Optimal recovery of aeromonads (167/186) occurred using BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h) with APW (25 degrees C; 24 h) subcultured to BAA (37 degrees C; 24 h) and CIN (25 degrees C; 48 h).     

Quantitative morphological investigations on smooth muscle cells in vascular surgical specimens and their clinical importance.

A distinct distribution of activated SMC could be demonstrated in atherosclerotic plaques and the neighbouring media of human beings. An increased proliferation was found in the younger age group and generally in the marginal regions of the plaques. The occurrence of activated SMC is thought to be a sequel of metabolic hypoxic damages. A high frequency of activated SMC is a bad prognostic sign in surgical specimens indicating a tendency for proliferation and occlusion.     

A method for chromosome preparations from large fish specimens using in vitro short-term treatment with colchicine

This paper describes a new technique for preparing mitotic fish chromosomes using short-term in vitro treatment with colchicine. The results show that a large number of good quality metaphases (many suitable for chromosome banding) can be obtained by this technique, which requires an average of 1 h and 30 min for all steps. The procedure considerably reduces the time normally required for chromosome preparations in fish.This work was supported by grants FUNCUNESP, FAPESP and CNPq.The authors are grateful to Mr Renato Devidé for technical assistance.     

Simple method for a medium-cell separation.

The present method makes possible a quick separation of cells from the medium with the aid of strips of filter paper and physiological solution. Cell suspension is put on the strip and all water soluble components are washed away by soaking in saline solution, while cells remain on the spot. The experiment on 14-C-uridine uptake proved the suitability of the method for membrane-transport studies.     

Evidence for changes in cell shape from a 2-dimensional to a 3-dimensional substrate.

Chick embryo mesoderm cells were explanted to culture systems in vivo and in vitro and their subsequent movements were correlated with the external morphology as studied by SEM. In vitro cell movements are exaggerations of normal in vivo movements where a 2-dimensional substrate is encountered rather than a 3-dimensional environment.     

Colored filters for microphotography: a costless 'do-it-yourself' solution.

Black and white microphotography makes use of several colored filters for an increased contrast. These filters are sometimes expensive and do not correspond exactly to the stain to be masked on the negative. Our specific colored filters contain a sufficient and adjusted amount of the dye used in the staining technic in an Agar medium.     

Oxygenation of a dipyrromethene model for bilirubin: formation of a singlet oxygen-like product.

An oxodipyrromethene model compound for bilirubin is found to undergo oxidation to a blue tetrapyrrole and a water-propentdyopent on a silica gel thin layer chromatography plate. The reaction involves ground state oxygen and requires silica gel, although the propentdyopent is an expected product from reaction with singlet oxygen.     

Evidence for a role of IFN gamma in control of Listeria monocytogenes in T cell deficient mice.

The role of interferon (IFN) gamma in controlling chronic infections of Listeria monocytogenes (Listeria) was studied in athymic C57BL/6 nu/nu mice, and by treating thymectomized C57BL/6 +/+ mice with monoclonal rat CD4 and CD8-specific monoclonal antibodies (Mab). Mice treated with a combination of the two T cell subset antibodies were similar to athymic, nude mice in being able to control Listeria infection, keeping the titers below 3-5 log10 bacteria per organ, but they could not eliminate them completely. Treatment with antibodies to IFN gamma of nude or CD4+ + CD8+ - T cell-depleted mice suffering from chronic Listeria infection caused a marked increase of Listeria titers in liver and spleen. This result implies a role of IFN gamma in maintaining anti-Listeria resistance in mice lacking mature T cells.     

Glycoprotein biosynthesis in splenic cells. Purification of a microsomal galactosyl-transferase.

One part of the microsomal galactosyl-transferase activity of splenic cells of rats can by solubilized by the action of Triton X-100 and Tween 20. Its purification on a Sephadex G-200 column and by electrophoresis on a polyacrylamide gel leads to a solution of high specific enzymic activity.     

Role of intracellular calcium in promoting muscle damage: a strategy for controlling the dystrophic condition.

It is suggested that various muscle diseases and examples of experimentally-induced muscle damage arise because of a high calcium level in the myoplasm. When [Ca2+]i is raised experimentally in amphibian or mammaliam muscle by treatment with A23187 or caffeine, myofilament degradation follows quickly. Such a rapid action suggests the involvement of a sequence of proteolytic activity that is stimulated by a rise in [Ca2+]i. Ca2+ might either trigger protease activity directly or indirectly, or promote the release of lysosomal enzymes. A high [Ca2+]i in dystrophic muscle is believed to be the resultant of a sequence of events that is summarized in the figure. Suggestions are presented for different ways in which the steady-state position of [Ca2+]i might ultimately be controlled for the clinical amelioration of some dystrophic conditions.     

The smooth endoplasmic reticulum as a possible storage site for dendritic dopamine in substantia nigra neurones.

In dendrites of the substantia nigra neurones the monoamine marker 5-hydroxydopamine injected intracerebrally was localized inside of smooth endoplasmic reticulum cisterns. This observation opens the possibility of the existence of an alternative site for dopamine storage in dendrites as opposed to the well-known vesicular storage.