Microbiological Immunocytochemistry: A Review of Current Trends and Applications

It has been considered worthwhile to update previous reviews of microbiological immunocytochemistry in order to identify areas of current importance in this continually expanding area of research. Publications in virology, bacteriology and protozoology indicate a continued interest in immunocytochemistry. Deployment of colloidal gold techniques is almost universal in these applications. The post-embedding technique was the most widely applied technique although a few studies employed the immunonegative stain, pre-embedding and immunoreplica techniques, thereby reflecting the use of colloidal gold in all other areas of the biological sciences

Bioapplication of Colloidal Gold in Microbiological Immunocytochemistry

Microbiological organisms are an ubiquitous group of animals encompassing bacteria, viruses, protozoa, algae and fungi. They are adapted for survival in many diverse habitats and exert a profound effect on man and his environment. Colloidal gold electron immunocytochemistry is a useful technique for studying these organisms and may be applied in several ways. The post-embedding technique is used to detect internal antigens, whilst the pre-embedding technique is employed for the detection of external antigens. In contrast the immuno-negative stain technique is applied to detect antigens on structures such as viruses or bacterial pili which may be dried down onto an electron microscope grid and immunolabelled in situ. In addition the immuno-replica technique allows the examination of cell surfaces for the appearance of antigens. Together these techniques have yielded valuable information concerning microbiological organisms

Incomplete Transition Complexity of Basic Operations on Finite Languages

The state complexity of basic operations on finite languages (considering complete DFAs) has been in studied the literature. In this paper we study the incomplete (deterministic) state and transition complexity on finite languages of boolean operations, concatenation, star, and reversal. For all operations we give tight upper bounds for both description measures. We correct the published state complexity of concatenation for complete DFAs and provide a tight upper bound for the case when the right automaton is larger than the left one. For all binary operations the tightness is proved using family languages with a variable alphabet size. In general the operational complexities depend not only on the complexities of the operands but also on other refined measures.Comment: 13 page

Markets, Government And Environmental Policy Issues For Public Transit

This paper considers the wider transport policy implications of bus deregulation, especially the links with environmental objectives. The major themes are the role of markets in creating opportunities through incentives to innovate which impact positively on the environment without the intervention of government, but which accord with political agendas, defining an appropriate set of goals and performance criteria for urban passenger transport which give credence to environmental sustainability, distinguishing outcome and outputs and structuring the regulator to deliver. We use the experience with mini-buses in Britain to show how markets create environmentally compatible incentives

Scanning X-Ray Microanalysis of Microcarrier Cultured Endothelial Cells: Elemental Changes During the Transition to Confluency and the Effect of Ionophore A23187

Porcine endothelial cells were grown on microcarrier beads and examined by scanning electron microscopy (SEM) at various times after initiation of culture. Total cell coverage on the bead surface varied from mean values of approximately 7% (3h) to 80% (96h). Beam penetration into the subcellular matrix presents a major problem with SEM X-ray microanalysis of microcarrier cultured cells and necessitates the use of an accelerating voltage not exceeding 10kV. At this voltage and below, X-ray contribution from elements present in the microcarrier bead has minimal effect on the determination of cell elemental levels. Washing the cells with 0.15M sucrose was the least perturbing of the rinsing techniques investigated. removing surface culture medium but not internal diffusible ions. X-ray microanalysis revealed detectable levels of Na, P, S, Cl, K and Ca in the cells, with well-marked changes from initial attachment to confluency. The level of K decreased from approximately 1.0% at 3h to 0.4% at 24h, with a corresponding decrease in the K/Na ratio. This unexpectedly low level of K was invariably observed after 24h, and is a genuine feature of established microcarrier culture. The effect of ionophore A23187 was determined at the 3h culture stage, and resulted in significant increases in the concentration of divalent cations (Mg2+, Ca2+), monovalent ions (Na+, Cl-) and a decrease in the level of K+

Ultrastructural Assessment of Lesion Development in the Collared Rabbit Carotid Artery Model

Cellular reactions associated with the formation of lesions generated in the carotid artery of rabbits fed either normal or high cholesterol diets by the placement of a flexible, silastic collar around the artery, were studied by electron microscopy. Endothelial cells remained as a monolayer throughout lesion development. The endothelial cell surface in both experimental and sham operated carotids, 4 hours and 8 hours after the initiation of the experiments, were covered with platelets and leukocytes. Neutrophils were present until 7 days in the arteries from within the collar of animals maintained on a normal diet, but only to 1 day in the cholesterol-fed animals. Neutrophils were observed within the medial layer. Few monocytes were identified. An intimal lesion had formed after 7 days in both groups of animals. Macrophage-like cells and foam cells were identified in the cholesterol-fed animals. The size of the lesion increased up to 56 days in animals maintained on a high cholesterol diet, but regression occurred after the 14-days sample in those animals on a normal diet. Concurrently a proportion of the smooth muscle cells changed from contractile to synthetic phenotype within the intimal and medial region of the collared artery of both high cholesterol and normocholesterolaemic animals. Lesions did not form in the contralateral, sham operated arteries