Confocal microscopy and exfoliative cytology

Comparative cytopathologic evaluation using acridine orange with Papanicolaou stain in psychoactive substances abusers with potentially malignant and malignant disorders

Introduction:

Oral cancer is a major health problem and its early detection is advantageous for therapeutic purposes. According to available evidence, the risks of oral malignancies increase with the usage of tobacco and other psychoactive substances (PSs). The present study showed expression pattern of nuclear and cytoplasmic changes from normal individuals without habit to oral potentially malignant disorders (OPMD) and oral squamous cell carcinoma (OSCC) in PS abusers with the help of fluorescence acridine orange (AO) stain and Papanicolaou (PAP) stain.

Aim and Objectives:

This study aimed to investigate and compare diagnostic efficacy of fluorescence microscopic evaluation of AO stain in cytological smears with PAP staining under light microscopy in PS abusers having oral potentially malignant and malignant lesions.

Materials and Methods:

Oral smears from 120 individuals among which 40 from potentially malignant disorders, 40 from oral malignancy and 40 normal buccal mucosa smears were prepared. One set of smears was stained by AO staining and the other by PAP staining and examined under fluorescence and light microscope, respectively. The results of both the stainings were evaluated by grading cytology smears in class-I to class-V cytology.

Results:

The AO fluorescence stain reliably demonstrated malignant cells based on the differential fluorescence. The efficacy of AO fluorescence stain was higher than PAP stain in screening of oral lesions suspicious of malignancy. The sensitivity of PAP staining and AO staining is 57.50% and 61.25%, respectively.

Conclusion:

As compared to PAP staining method, fluorescent AO method is more effective in screening of OPMD and OSCC in PS abusers.

Multicomponent analysis using a confocal Raman microscope

Measuring the concentration of multiple chemical components in a low-volume aqueous mixture by Raman spectroscopy has received significant interest in the literature. All of the contributions to date focus on the design of optical systems that facilitate the recording of spectra with high signal-to-noise ratio by collecting as many Raman scattered photons as possible. In this study, the confocal Raman microscope setup is investigated for multicomponent analysis. Partial least-squares regression is used to quantify physiologically relevant aqueous mixtures of glucose, lactic acid, and urea. The predicted error is 17.81 mg/dL for glucose, 10.6 mg/dL for lactic acid, and 7.6 mg/dL for urea, although this can be improved with increased acquisition times. A theoretical analysis of the method is proposed, which relates the numerical aperture and the magnification of the microscope objective, as well as the confocal pinhole size, to the performance of the technique.

Proflavine Hemisulfate as a Fluorescent Contrast Agent for Point-of-Care Cytology

Proflavine hemisulfate, an acridine-derived fluorescent dye, can be used as a rapid stain for cytologic examination of biological specimens. Proflavine fluorescently stains cell nuclei and cytoplasmic structures, owing to its small amphipathic structure and ability to intercalate DNA. In this manuscript, we demonstrated the use of proflavine as a rapid cytologic dye on a number of specimens, including normal exfoliated oral squamous cells, cultured human oral squamous carcinoma cells, and leukocytes derived from whole blood specimens using a custom-built, portable, LED-illuminated fluorescence microscope. No incubation time was needed after suspending cells in 0.01% (w/v) proflavine diluted in saline. Images of proflavine stained oral cells had clearly visible nuclei as well as granular cytoplasm, while stained leukocytes exhibited bright nuclei, and highlighted the multilobar nature of nuclei in neutrophils. We also demonstrated the utility of quantitative analysis of digital images of proflavine stained cells, which can be used to detect significant morphological differences between different cell types. Proflavine stained oral cells have well-defined nuclei and cell membranes which allowed for quantitative analysis of nuclear to cytoplasmic ratios, as well as image texture analysis to extract quantitative image features.

In vivo microstructural analysis of enamel in permanent and deciduous teeth

Confocal microscope was used to analyze human enamel from 10 deciduous and 10 permanent teeth. Optically sectioned images were obtained. A more intense autofluorescence was found in primary teeth. This finding might be due to the greater presence of organic substances in deciduous enamel. The mean prism diameter measurement in permanent teeth enamel was 3.150 µm and 2.602 µm in deciduous teeth. The mean prism diameter in deciduous teeth was statistically least. The results indicate that a confocal microscope may be of help in analyzing and defining the microscopic features of human enamel.