Xviii.—polyethylene Glycols as Histological Embedding Media: With a Note on the Dimensional Change of Tissue During Embedding in Various Media

Abstract

Synopsis The literature is reviewed. A technique for embedding tissues in polyethylene glycol 1,000 mono‐stearate (Nonex 63B) after preliminary infiltration with polyethylene glycol 900 is described. Preliminary dehydration in alcohol is not required and at no stage is the temperature of the tissue raised above 40° C. Measurement of tissue before and after embedding in Nonex, paraffin and celloidin shows that there is significantly less shrinkage in Nonex. It is shown that the celloidin in celloidin‐Nonex mixtures used experimentally for embedding penetrates tissue. The difficulty of mounting Nonex sections is discussed. Nonex sections stain well, phosphatase activity is well preserved and at least part of the lipid is preserved. It is concluded that the use of Nonex is specially indicated for tissues liable to shrinkage artefacts and may have some advantage for histo‐chemistry.

Changes in dimensions of large cancellous bone specimens during histological preparation as measured on slabs from human femoral heads

“…However, it seems that the degree of shrinkage of paraffin-embedded tissue is not caused by compression of the tissue by the contracting wax, but rather by the prolonged high temperature of the wax oven [9,10]. Our figures of about 6% shrinkage after embedding in 56-57~ Paraplast correspond to similar figures quoted by Miles and Linder [2] also for cancellous bone, as compared to the shrinkage of the paraffin-embedded compact bone, which they quote to be about 4%. Because of this obvious and constant reduction in size after paraffin wax embedding, many authors recommend embedding tissue in cellulose nitrate (celloidin or low-viscosity nitrocellulose [LVN]) [11] or in polyethylene glycol [2].…”

“…Patten and Philpott [1] recorded shrinkage of tissue in pig embryos in a variety of fixatives and at different stages of paraffin wax embedding. Miles and Linder [2] studied the influence of various embedding media on dimensional changes in different tissues including cancellous bone, and A. Smith [3] investigated the effect of drying on tissue sections after cutting and also changes in their stainability due to adherence to the microscopic slide. Brain [4] studied and measured quantitative changes during the dehydration and clearing processes in several agents and also while cutting a decalcified head of a mouse fetus.…”

“…The quantitative changes observed in various tissues after different treatments were measured by various authors either as changes in the weight and volume [5], changes in linear size measured by 0171-967X/83/0035-0001 $01.00 microscope or microcalipers [2], or by taking measurements from photographs of the tissue [4]. For accurate measurement we used the simple technique of electrostatic (Xerox) copying recommended for recording the morphology of hard tissues [6], in which the features of bone samples are copied in the same way as any printed material, their real dimensions being preserved.…”

Pathology of Bioabsorbable Implants in Preclinical Studies

“…If the test material must be retained in the tissue sections, then cryopreservation and cryomicrotomy may be considered. Direct infiltration using hydrophilic embedding media such as glycolmethacrylate or PEG may also be considered (Miles and Linder 1952). However, care must be taken to avoid exposing the microscopic tissue preparation to reagents that dissolve the implant material during slide staining.…”

Digoxin, Ouabain and Potassium Movements in Rabbit Auricles

“…Cell Dimensions.-Auricles were cooled or were poisoned with ouabain until they ceased to beat and were then fixed in saline containing 10% (v/v) of neutralized formalin, and embedded in polyethyleneglycol-1000 monostearate (Miles and Linder, 1952). Sections were stained with haematoxylin and van Gieson, magnified x 1,000 and projected on a screen so that the diameter of the cells could be measured.…”