An Immuno-Electron Miscroscopy Study of the Slime Layer Antigen of Pseudomonas Aeruginosa

This investigation was concerned with the relationship of the slime layer material of Pseudomonas aeruginosa, Verder and Evans strain 1369, to the presumably somatic "O" type of antigen used by these authors as the base for their serological schema

Systematic top-down approach to clinical chemistry

This paper introduces a systematic approach to organizing the discipline of clinical chemistry. The approach is called a top-down, systems approach because it starts at the top with the most general concepts and works down through less general concepts to the most specific details and techniques. The hypothesis is that the discipline can be organized into hierarchical levels of functional processes and operational approaches to those processes. The functional processes represent what clinical scientists do; the operatinal approaches represent how they do it. Because functional processes change little, if at all, with time, they are used to develop a stable infrastructure or framework for the discipline. That infrastructure is then used to organize and understand operational approaches that tend to change rapidly with time in response to technological advances. The paper begins with the most general functional processes and then uses selected examples of the more general functions to illustrate lower hierarchical levels or functional processes and operational approaches

Increasing the biosafety of analytical systems in the clinical laboratory

Biosafety is an important part of the know-how of all clinical laboratory professionals. Biosafely must have high priority in the design and use of analytical systems. Attention should be focused on reducing the handling of biological specimens, reducing biohazards to laboratory personnel, and on improving the labelling and containment of biohazardous materials. In this paper, biosafety issues are discussed in relation to the design of analytical systems, their use and maintenance

Multiple inducers of the Drosophila heat shock locus 93D (hsr omega): inducer-specific patterns of the three transcripts

The Drosophila hsr omega locus produces one of the largest and most active heat shock puffs, yet it does not encode a heat shock protein. Instead, this locus produces a distinctive set of three transcripts, all from the same start site. The largest transcript, omega 1, is limited to the nucleus and appears to have a role there. A second nuclear transcript, omega 2, is produced by alternative termination and contains the sequence found in the 5' 20-25% of omega 1 (depending on the Drosophila species). The cytoplasmic transcript, omega 3, is produced by removal of a 700-bp intron from omega 2. All three hsr omega RNAs are produced constitutively and production is enhanced by heat shock. In addition to being a member of the set of heat shock puffs, the hsr omega puff is induced by agents that do not affect other heat shock loci, suggesting that hsr omega is more sensitive to environmental changes than other loci. We report here that agents that induce puffing of hsr omega loci in polytene nuclei also lead to an increase in hsr omega transcripts in diploid cells. We also show that the relative levels of omega 1 and omega 3 can be modulated independently by several agents. All drugs that inhibit translation, either initiation or elongation, stabilize the omega 3 transcript, which normally turns over within minutes in control cells. Drugs (such as benzamide and colchicine) that induce puffing of hsr omega, but not other heat shock loci, lead to large increases in omega 1. Although the constitutive level of omega 1 is relatively stable, the drug-induced excess is lost rapidly when the drug is withdrawn. The relative levels of hsr omega transcripts may reflect different states in cellular metabolism