Microscopic fat cellsize measurements on frozen-cut adipose tissue in comparison with automatic determinations of osmium-fixed fat cells

Abstract

Diameters of fat cells in adipose tissue slices, floating in an isoosmolar solution, were measured under a microscope. The slices were obtained from percutaneous biopsies by freeze-cutting after brief formaldehyde fixation. All cells in a given part of the slice were measured, thus avoiding selection. A normal distribution of fat cell diameters could be demonstrated with this method, as has been found with previously described methods. The error of the method was 2.6% for diameter and 8.0% for weight determinations. Storage of adipose tissue at 4°C for 48 hr had no effects on cell size determinations.Results with this micrcscopic method were compared with those obtained from a previously described method for automatic determinations of osmium-fixed fat cells. The latter method was slightly modified by using a viscous electrolyte, which prevented sedimentation of large fat cells, and by using sonication to complete cell separation. The methods agreed closely.A method for calculating mean fat cell weight using osmium-fixed fat cells is described, which makes determinations of sample wet weight and ratio of lipid to wet weight unnecessary.

Keywords

• electronic determination
• osmium tetroxide
• sonication
• glycerol electrolyte
• Celloscope
• Coulter Counter