Page 291 - Textbook of Pathology, 6th Edition

fluorescent or F body (Y chromatin). The number of Barr 275
bodies observed in interphase nuclei is one less than the
number of X chromosome (n–1), whereas the number of F
bodies observed is equal to the number of Y chromosomes
present (n). In effect, the Barr body is specific for females
and the F body for males (page 257). CHAPTER 11
1. DEMONSTRATION OF BARR BODY (X CHROMA-
TIN). In buccal smears, the Barr body appears as a plano-
convex mass about 1 μm in diameter applied to the inner
surface of the nuclear membrane. The interphase nuclei of
one hundred intermediate squamous epithelial cells are
scrutinised. In normal females, Barr bodies are present in at
least 20% of nuclei (Fig. 11.8, A). Males have a Barr body
count of less than 2%. Vaginal smears may also be used for
Barr body counts (page 257).
2. DEMONSTRATION OF THE F BODY (Y CHROMA- Figure 11.8 Sex chromatin. A, Buccal smear showing condensation Basic Diagnostic Cytology
TIN). Demonstration of the F body requires fluorescent of chromatin under the nuclear membrane. B, Blood film showing
presence of drumstick appendage attached to a nuclear lobe of the
staining in contrast to the Barr body which may be observed neutrophil.
on routine Papanicolaou-stained smears. On staining buccal
smears with quinacrine mustard, the intensely fluorescent F
body is observed in about 60% of interphase nuclei in males iv) The ectocervix is sampled with the Ayre’s spatula
(Fig. 11.9). The longer limb of the spatula is fitted into the
and in less than 8% of nuclei in females. The F body is also external os and the spatula rotated through 360° to sample
demonstrable in the nuclei of lymphocytes in a peripheral the entire cervix. The scraped material on the spatula is then
blood film stained with quinacrine mustard.
placed on the drop aspirated from the vaginal pool and the
3. COUNTING OF DRUMSTICK APPENDAGE. The smear prepared with the spatula itself or with the tip of the
presence and frequency of drumstick appendages attached gloved finger (cotton swabs may be used instead of the Ayre’s
to nuclei of polymorphonuclear leucocytes on a peripheral spatula, although the quality of smears is not as good).
blood film may also be used for determining sex. At least v) Thin uniform smears should be prepared and the slide
500 neutrophilic leucocytes are scrutinised in a Romanowsky- immediately immersed in fixative to avoid artefacts in cells
stained blood film. Genetic females show drumsticks in 3- caused by drying.
6% of neutrophils (Fig. 11.8, B). In males, the frequency of vi) Smears should be transported to the laboratory in the
drumsticks is less than 0.3%. fixative in a Coplin’s jar (discussed later).
Slides should ideally be labelled by using a diamond
TECHNIQUES IN EXFOLIATIVE CYTOLOGY pencil. If labels of sticking plaster are used, the labels must
not come into contact with the fixative.
A brief resume of methods for collection of specimens and
processing of samples for exfoliative cytodiagnosis is 2. LIQUID-BASED CYTOLOGY PREPARATIONS (THIN
outlined below under 4 headings: collection, fixation and PREPS). This is a special technique for preparation of
fixatives, processing in the laboratory, and staining. gynaecologic and non-gynaecologic samples which provides
uniform monolayered dispersion of cells on smears, without
overlapping or clump formation. It is a pre-requisite for
A. Collection of Samples
quantitative analysis and automated devices.
1. PREPARATION OF COMBINED (FAST) SMEARS.
Smears should not be taken during menstrual bleeding. The 3. PREPARATION OF LATERAL VAGINAL SMEARS
patient should not douche for at least 24 hours before the (LVS). The LVS is obtained by scraping the lateral walls of
smear is obtained. the upper third of the vagina (at the level of the cervical
external os) with the flat surface of a wooden tongue
i) Smears are obtained under direct vision after introducing depressor and smearing the material directly onto labelled
a Cusco’s speculum with the patient in lithotomy position. slides. The patient is prepared and positioned as described
ii) Ideally, lubricants and medical jellies should not be used for the combined (fast) smear.
for introducing the speculum since use of lubricants results 4. COLLECTION OF SPUTUM. Fresh, unfixed, early
in contamination of the smear. If required, the speculum may morning specimens resulting from overnight accumulation
be moistened with a few drops of normal saline.
of secretions are best for diagnostic purposes. A minimum
iii) The posterior fornix of the vagina is aspirated with a of at least three specimens collected on three successive days
blunt-ended glass pipette fitted with a rubber bulb. A drop of should be examined. The patient is instructed to cough
the aspirate is placed at the unlabelled end of a glass slide. deeply on waking up and to expectorate all sputum into a