Efficacy of modified rapid economic acetic acid-based Papanicolaou stain

BACKGROUND

Papanicolaou (Pap) staining is used with various modifications for the staining of cervical smears. It gives a good contrast with sharp nuclear features which aid in accurate interpretation. However, it utilises ethyl alcohol, which is expensive and difficult to purchase. We have attempted to devise a rapid Pap technique which uses acetic acid instead of ethyl alcohol, and yet provides good staining for correct diagnosis.

METHODS

Liquid-based cytology samples were collected from 102 patients as a part of routine screening. Two smears were prepared from each sample, which were stained with conventional as well as rapid Pap. In the rapid Pap method, the smears were fixed in methanol and dehydration was performed before and after OG6 with 0.5% acetic acid. The final dehydration was performed with methanol. Smears from both techniques were compared by two independent observers for staining quality.

RESULTS

With the rapid Pap stain, nuclear staining was comparable with that of conventional Pap (P < 0.05). Cytoplasmic staining was optimal in 69.6% of cases; however, the suboptimal staining in the rest of the smears did not pose any diagnostic problem.

CONCLUSION

The rapid Pap technique is a cost-effective alternative to conventional Pap which also saves time and provides good staining quality without compromising the diagnostic interpretation.

Desiccation of a clay film: cracking versus peeling

We report a simulation study on competition between cracking and peeling, in a layer of clay on desiccation and how this is affected by the rate of drying, as well as the roughness of the substrate. The system is based on a simple 2-dimensional spring model. A vertical section through the layer with finite thickness is represented by a rectangular array of nodes connected by linear springs on a square lattice. The effect of reduction of the natural length of the springs, which mimics the drying is studied. Varying the strength of adhesion between sample and substrate and the rate of penetration of the drying front produces an interesting phase diagram, showing cross-over from peeling to cracking behavior. Changes in the number and width of cracks on varying the layer thickness is observed to reproduce experimental reports.