Measuring intracellular enzyme concentrations

Measuring Intracellular Ions

An optical multifrequency phase-modulation method using microbeads for measuring intracellular oxygen concentrations in plants.

A technique has been developed to measure absolute intracellular oxygen concentrations in green plants. Oxygen-sensitive phosphorescent microbeads were injected into the cells and an optical multifrequency phase-modulation technique was used to discriminate the sensor signal from the strong autofluorescence of the plant tissue. The method was established using photosynthesis-competent cells of ...

Azithromycin Pharmacokinetics and Intracellular Concentrations

Azithromycin pharmacokinetics in LegioneUa pneumophila-infected and uninfected guinea pigs were assessed by measuring the drug concentration in whole lungs or the drug content in bronchoalveolar lavage (BAL) fluid in separate experiments. Azithromycin concentrations were measured by using a bioassay. The mean azithromycin content in the BAL fluid of infected guinea pigs was higher than that in ...

Intestinal cholesterol esterase: intracellular enzyme

The location of cholesterol esterase in rabbit intestine was re-evaluated. In three different experiments that were designed to eliminate contaminating mucus and pancreatic enzymes from the lumen of the small intestine, it was observed that the activities of cholesterol esterase and amylase in intestinal cytosol and whole homogenate decreased in parallel fashion. After the mucus was carefully w...

Interrelation Between Pinacidil and Intracellular ATP Concentrations

The patch-clamp technique was used to study the relation between pinacidil and intracellular ATP concentration ([ATP]i) on the activation of the outward K' current in guinea pig ventricular myocytes. Pinacidil shortened the action potential duration, exhibiting stronger effect at 2 mM [ATP]i than at 5 mM [ATP]i. Pinacidil at 5 ,M or higher concentrations activated the time-independent outward c...