The routine counting of obligate anaerobic bacteria is a serious problem in many laboratories. Reliable anaerobic chambers are either expensive or messy and cumbersome. Furthermore, the exposure of certain genera, notably Bacteroides and some spirochetes, to air may kill the organisms. The following technique does not require an anaerobic chamber, does not expose the organism to atmospheric oxy...

A method is outlined for obtaining giga-ohm seals on intracellular membranes in intact cells. The technique employs a variant of the patch-clamp technique: a concentric electrode arrangement protects an inner patch pipette during penetration of the plasma membrane, after which a seal can be formed on an internal organelle membrane. Using this technique, successful recordings can be obtained wit...

It is thought that the stress concentration at the root apex caused by orthodontic force induces root resorption. The purpose of this study was to investigate stress distribution at the root in cases of deviated root shapes using finite element models (FEMs). To clarify this, five three-dimensional FEMs divided by deviated root shape (normal, short, blunt, bent root apex, pipette shape) were co...

CLINICAL CHEMISTRY, Vol. 23, No. 6, 1977 1189 +2.73% (Table 1). However, the “forward” technique manifested both constant (non-zero intercept; t = -4.0, P < 0.05) and pipette-size related (slope significantly <1.0; t = 5.27, P <0.01) inaccuracies. Deviations ranged from -6.31% to -12.0% of the intended value. Precision was similar using either technique (coefficients of variation, Table 1). We ...

Virtually nothing is known about the activity of morphologically identified neurons in freely moving mammals. Here we describe stabilization and positioning techniques that allow juxtacellular recordings from labeled single neurons in awake, freely moving animals. This method involves the use of a friction-based device that allows stabilization of the recording pipette by friction forces. Frict...