Air-dried smears

Fulciniti F, Frangella C, Staiano M, et al. Air-dried smears for optimal diagnostic immunocytochemistry. Acta Cytol. 2008 52 178-186. 

Some of the important prerequisites for adequate IHC studies are a well-spread film of cells on a glass slide, adequate fixation, removal of blood and proteinaceous material, and a sensitive, reproducible method of immunocytochemistry (ICC)." Wet fixation in alcohol (WFA) must be performed without delay because partial air drying may result in false-positive results. Air-dried smears (ADS) are often more cellular than alcohol-fixed slides because some material often floats off the slide when it is alcohol fixed. Using air-dried slides minimizes cell loss and results in a more even film of cells. Such slides must be fixed immediately before performing IHC, and the types of preferred fixatives vary among cytopathologists. Cold acetone and 95% alcohoF are common fixatives, and B5 may be used for lymphoid markers and neuroendocrine antibodies. ... 

Ng WF, Choi FB, Cheung LLH, et al. Rehydration of air-dried smears with normal saline Application in fluid cytology. Acta Cytol. 1994 38 56-64. 

Heat fixation Technique in which air-dried smears are passed through an open flame so that organisms are killed, adhere better to the side, and take up dye more easily. 

Farhood16 specimens paired in Pap smear and cell block for comparison Not de-stained solution, pH 8, steamed for 40 min 8G7G3/1, Dako) Pap-stained smears gave identical positive rate as that obtained by cell block, but air-dried slides were unreliable. 

FNA specimens are received at the cytopathology laboratory as direct smear, fixed in 70% ethyl alcohol or air dried or as fluid. 

Air drying, usually with subsequent chemical post-fixation, is applicable for cell smears, cytospins and cryosections. Snap freezing (usually in liquid nitrogen) is routinely employed for tissue probes for subsequent cryosectioning. Chemical fixation is commonly carried out in aldehydes (e.g. formaldehyde) for tissue probes and cultured cell monolayers, and in acetone or alcohols (methanol or ethanol) for cryosections and cell preparations. 

This type of fixation is often used for cryosections, cell smears and cell monolyers, but can not be recommended for fixation of tissue blocks since acetone and alcohols, as opposed to aldehydes, penetrate tissue poorly. Cryosections, cell smears and cell monolyers after short (for 5 15 min) fixation in alcohols or acetone are usually air-dried (for 1 h or overnight), washed in buffered saline and directly subjected to the immunocytochemical analysis. 

A suspension of a cell line (usually T lymphocyte lines such as HG, HUT-78, or CEM) infected with HIV is spotted on microscope slides, air dried, and fixed in acetone. Addition of uninfected cells to the suspension provides a means for detecting nonspecific reactions in the same smear. Typical localized fluorescence of infected cells is seen after reaction with positive sera. Little or no fluorescence is seen with negative sera. 

Imprints (touch preps), squash preps, scrape preps Smear Ethanol or air-dried-acetone... 

The polished surfaces of polycrystalline Al, Cu, Ni and Si(p) and monocrystalline samples of Mo, Si(m) and W were tested to choose the best substrate providing maximal colour contrast. The surface of the substrate was chemically polished to provide mirror reflection. Thin blood smears of the same patient were deposited under the same experimental conditions. After air drying for 10 min, blood samples were placed on the microscope holder. The images were taken by a digital camera. 

This method applies to both stained and unstained routinely collected smears. If previously stained (e.g., with Papamcolau stain) and mounted, the cover slip and most of the stain can be removed by soaking the slides in xylene (this may take up to 48-72 h). Following this, the xylene should be removed using 99% (industrial-grade) ethanol, and the slides then soaked in distilled water and air-dried. 

Thin, uniformly spread cell smears are prepared on glass slides and then rehydrated with normal saline for 3 min. This is followed by air-drying for 24 hr and fixation with 0.1% formal saline (1,000ml of normal saline and 2.5ml of 40% formalin) for 2-14 hr postfixation is accomplished with 95-100% ethanol for 10 min. The sections are heated in 10 mM citrate buffer (pH 6.0) in a microwave oven for 5 min at boiling and then allowed to remain in the hot solution for another 5 min before being removed for immunostaining. 

Samples should be smeared onto glass slides and air-dried prior to staining with Gram stain or methylene blue (Appendix 2). 

Imprints (Touch preps). Smear Ethanol or air-dried-... 

Take small alicluots of cells to prepare cell smears on the slide for detection of viral antigens. Air-dry the cells, fix the cells in cold acetone for 10 min, air-dry, and then perform indirect immunofluorescent assay (see Appendix 1). 

Randall B, van Amerongen L. Commercial laboratory practice evaluation of air-dried/rehydrated cervico-vaginal smears vs traditionally-fixed smears. Diagn Cytopathol. 1997 16 174-176. 

Make a direct or cytofuge smear of the infected cells of interest (e.g., infected neutrophils or HL60 cells). Air dry. 

Stain air-dried blood smears or cells cytocentrifuged onto a slide for 10 min at room temperature. 

Tensile bond strength (TBS) were determined using a testing protocol and assembly previously described (6). To assess the efficacy of smear layer removal by aqueous AA the surface of 1 mm thick dentin cross sections were pretreated with one drop (0.05 mL) of AA (17.6 wt. % in distilled HjO pH = 2.0). The durations of AA treatment were 15, 30, 45, 60, and 120 s. l ch AA treated dentin surface was rinsed with distilled water for 10 s and then was air dried. The dentin specimens were then sputter coated with gold for evaluation by scanning electron microscopy (SEM). 

---