Differences in splenic B-lymphocyte ganglioside expression and accessibility in normal and endotoxin-hyporesponsive mice.

Endotoxin-responsive (C3H/HeN) and -hyporesponsive (C3H/HeJ) murine B lymphocytes purified by adherence to anti-immunoglobulin ("antibody panning") possess identical gangliosides but different ganglioside surface accessibilities. We investigated the distribution and surface accessibility of gangliosides of B lymphocytes purified by adherence to plastic ("plastic panning") or by subtraction of non-B-lymphocyte components. As with antibody panning, there were no entirely new or absent gangliosides in plastic-panned or subtraction-purified B lymphocytes of each strain.

Neuroanatomy of tinnitus.

We tested the hypothesis that tinnitus was due to excessive spontaneous activity in the central auditory system by seeking cerebral blood flow (CBF) changes that paralleled changes in the loudness of tinnitus in patients able to alter the loudness of their tinnitus. We found CBF changes in the left temporal lobe in patients with right ear tinnitus, in contrast to bilateral temporal lobe activity associated with stimulation of the right ear. The tones activated more extensive portions of the brain in patients than controls.

Positron emission tomography in the study of hepatic encephalopathy.

Positron-emission tomography (PET) is a quantitative technique that produces images of biological or physiological processes. The nature of the image depends on the tracer used: common tracers used to study HE include 18F-fluordeoxyglucose, a marker of glucose metabolism; 15O-water, a marker of cerebral blood flow; and 13N-ammonia, a marker of ammonia metabolism. Combined blood flow and ammonia metabolism studies can be used to calculate the permeability surface area product for ammonia at the blood brain barrier.