Immunological investigations of meningococcal disease. III. Brevity of group C acquisition prior to disease occurrence.

A surveillance program to determine group C meningococcal acquisition in military personnel during an epidemic was made. Data from fortnightly nasopharyngeal cultures show that individuals who were admitted with meningococcal disease acquired the organism within a week of disease onset. There were 24 company/platoons in which a single case occurred.

Fluorogenic substrate turnover in single living cells.

Intracellular diffusion properties and enzyme activities in single living cells can be analysed by means of fluorogenic substrates that diffuse into the cells where they are converted into a fluorescent product by an enzymic reaction. The reaction-kinetic analysis of this process as a system of consecutive reactions provides information on the diffusion of the substrate into the cells, on intracellular enzyme activities and on the efflux of the fluorescent product. Separation of diffusion and enzyme-mediated processes is obtained by inducing specific changes of the cellular membrane using gramicidin D.