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ANITA RAUCH
Buccal smears
The oral cavity is covered by a mostly nonkeratinized squamous epithelium. Keratinization occurs only at the gingiva and lingual villi. While the
oral mucosa is regenerated through mitotic activity of the basal layer,
superficial cell layers are permanently peeled off and found in the saliva.
Therefore epithelial cells from the oral mucosa are easily accessible by a
simple buccal smear without any pain.
Urinary cells
Urine sediment contains many exfoliative cells from the epithelial layer of
the kidney pelvis, ureter, bladder, urethra, vagina, and prostate, i.e. from
the urothel. Urine cells are usually investigated for aneuploidy in bladder
cancer or for chromosomal mosaicism in mental-retardation syndromes.
Urine cells can be cultured similarly to amniotic fluid to obtain metaphase
spreads as described in the Springer cytogenetic lab manual (Korner et al.
1999). However, it is difficult to avoid contamination from bacteria or
yeast. Much easier and less time-consuming is the preparation of urine
cells for interphase FISH. This was successfully invented for the diagnosis
and follow-up of bladder cancer (Meloni et al. 1993). In clinical cytogenetics, it provides an ideal method to study tissue mosaicism of aneuploidy, especially in trisomy and tetrasomy 20q (Pfeiffer et al. 1998), where the
aneuploidy is often restricted to urothel which is also found in amnion
fluid (Koskull et al. 1984).
The major prerequisite for analysis of urine cells is to prevent the cells
from being damaged by toxic urine components. Therefore the urine sample is ideally prepared immediately after urination, or at least within 3 h.
Outline
The procedure of interphase FISH on epithelial cells from buccal smears or
urinary sediment is outlined in Fig. 1.
ANITA RAUCH
Buccal smears
The oral cavity is covered by a mostly nonkeratinized squamous epithelium. Keratinization occurs only at the gingiva and lingual villi. While the
oral mucosa is regenerated through mitotic activity of the basal layer,
superficial cell layers are permanently peeled off and found in the saliva.
Therefore epithelial cells from the oral mucosa are easily accessible by a
simple buccal smear without any pain.
Urinary cells
Urine sediment contains many exfoliative cells from the epithelial layer of
the kidney pelvis, ureter, bladder, urethra, vagina, and prostate, i.e. from
the urothel. Urine cells are usually investigated for aneuploidy in bladder
cancer or for chromosomal mosaicism in mental-retardation syndromes.
Urine cells can be cultured similarly to amniotic fluid to obtain metaphase
spreads as described in the Springer cytogenetic lab manual (Korner et al.
1999). However, it is difficult to avoid contamination from bacteria or
yeast. Much easier and less time-consuming is the preparation of urine
cells for interphase FISH. This was successfully invented for the diagnosis
and follow-up of bladder cancer (Meloni et al. 1993). In clinical cytogenetics, it provides an ideal method to study tissue mosaicism of aneuploidy, especially in trisomy and tetrasomy 20q (Pfeiffer et al. 1998), where the
aneuploidy is often restricted to urothel which is also found in amnion
fluid (Koskull et al. 1984).
The major prerequisite for analysis of urine cells is to prevent the cells
from being damaged by toxic urine components. Therefore the urine sample is ideally prepared immediately after urination, or at least within 3 h.
Outline
The procedure of interphase FISH on epithelial cells from buccal smears or
urinary sediment is outlined in Fig. 1.