Target-based drug discovery: Applications of fluorescence techniques in high throughput and fragment-based screening.

Target-based discovery of first-in-class therapeutics demands an in-depth understanding of the molecular mechanisms underlying human diseases. Precise measurements of cellular and biochemical activities are critical to gain mechanistic knowledge of biomolecules and their altered function in disease conditions. Such measurements enable the development of intervention strategies for preventing or treating diseases by modulation of desired molecular processes. Fluorescence-based techniques are routinely employed for accurate and robust measurements of in-vitro activity of molecular targets and for discovering novel chemical molecules that modulate the activity of molecular targets. In the current review, the authors focus on the applications of fluorescence-based high throughput screening (HTS) and fragment-based ligand discovery (FBLD) techniques such as fluorescence polarization (FP), Förster resonance energy transfer (FRET), fluorescence thermal shift assay (FTSA) and microscale thermophoresis (MST) for the discovery of chemical probe to exploring target's role in disease biology and ultimately, serve as a foundation for drug discovery. Some recent advancements in these techniques for compound library screening against important classes of drug targets, such as G-protein-coupled receptors (GPCRs) and GTPases, as well as phosphorylation- and acetylation-mediated protein-protein interactions, are discussed. Overall, this review presents a landscape of how these techniques paved the way for the discovery of small-molecule modulators and biologics against these targets for therapeutic benefits.

Natural sweeteners as fixatives in histopathology: A longitudinal study.

BACKGROUND: Fixation is the essential step in histopathological processing of tissues. Since formalin is a corroborated biohazard, its routine use as a fixative is a major health and safety concern and hence the quest for safer alternatives is envisaged. Natural sweeteners like jaggery and honey have proved to be effective tissue preservatives over 24 h. This pioneer eco-idea needs further research to expand its application. AIM: (1) To evaluate the fixative property of jaggery and honey over 6 months and ascertaining the results using hematoxylin and eosin stain (H and E). (2) To evaluate the compatibility of jaggery and honey fixed tissues for special stains - Periodic acid Schiff (PAS) and Masson-Trichrome (MT). MATERIALS AND METHODS: Equal bits of commercially available animal mucosae were preserved in 30% jaggery, 20% honey, and 10% buffered formalin (control) over 6 months at intervals. Following which, tissues were subjected to routine H and E, special stains - PAS and MT using standard operating procedures established in our group. RESULTS: Formalin, jaggery, and honey yielded satisfactory results post 6 months for H and E and special stains, jaggery was comparable to formalin in tissue preservation. CONCLUSION: We propose the use of eco-friendly jaggery and honey as alternatives to formalin for long term tissue preservation.

Evaluation of serum lipids and lipoproteins as prognosticators in leukoplakia.

BACKGROUND: Oral cancer is the 8th most common cancer worldwide. Squamous cell carcinomas constitute 94% of all oral malignancies and are often preceded by leukoplakia. Despite many adjunctive techniques to monitor transformation of leukoplakia to oral squamous cell carcinoma (OSCC), the mortality rate is on the rise. Incidentally, patients diagnosed with oral potentially malignant disorders (OPMDs) and oral cancers manifest with low choles-terol levels. Given a thought, hypolipidemia may be a useful adjunctive tool as it reflects the initial changes within the neo-plastic cells, thus giving a red alert in malignant transformation of leukoplakia at the earlier stage. AIM: To evaluate the feasibility of serum lipid profile as an adjunct early marker for malignant transformation of leukoplakia to OSCC. OBJECTIVES: To estimate the serum cholesterol, triglycerides and lipoprotein (HDL, LDL, VLDL) levels in patients with leukoplakia, OSCC and age matched healthy control group. To compare the serum cholesterol, triglycerides and lipoprotein levels between patients of leukoplakia, OSCC and age matched healthy control group. MATERIALS AND METHODS: The study group comprised of selected 30 individuals which included 10 each of histopathologically confirmed OSCC, leukoplakia and healthy controls. A written consent was taken from all of them, and a thorough case history was recorded and then venous blood was collected 12 hours post fasting and centrifuged. The serum cholesterol, triglycerides and HDL were estimated by enzymatic and colorimetric methods using commercially available kits--Roche/ Hitachi cobas systems. Chemistry assay QC procured from Bio-Rad was used as control. VLDL and LDL were derived from these values. Results were statistically analyzed using ANOVA and post hoc Tukey Test. RESULTS: Oral squamous cell carcinoma patients demonstrated significantly lower mean serum cholesterol level (151.60 mg/dl) than the control group (183.70 mg/dl). The mean cholesterol level in leukoplakia patients (173.90 mg/dl) was lower than that of control group (183.70 mg/dl) but higher than that of the OSCC group (151.60 mg/dl) with no statistical significance. CONCLUSION: Convenience, universal availability, patient compatibility and simplicity being the merits of serum lipid profile make it a feasible adjunctive prognosticator in leukoplakic patients.

Oral cytokeratins in health and disease.

The dynamics of oral mucosa is known by its inherent defensive nature. Certain areas demand tough shield when subjected to mechanical insults. This is met by structural scaffolding material referred as cytoskeleton comprised of intracellular protein filaments called cytokeratins in the surface squames of oral epithelia. They also equally contribute towards the architecture of odontogenic apparatus and salivary gland. Differentiation of epithelial cells within stratified epithelia regulates the expression of specific keratin gene. Any mutation in, or autoantibodies to keratins, desmosomal and cornified envelope proteins is translated into genetic and acquired human disorders. Sound knowledge of structural proteins, their expression, distribution and function plays a vital role in acquainting with these disorders and their application as differentiation markers. Thus, they form an integral aid in diagnostic pathology and may be instrumental in the future interventions by gene therapy. This review focuses on basics to current updates on oral cytokeratins with an emphasis on the genetic and acquired disorders of cytokeratins with oral implications.

A foreigner in squamous cell carcinoma!

Giant cells are the soldiers of defensive system of our body. They differ based on the stimuli that provoked their formation. On the other hand, squamous cell carcinoma (SCC) being the most common oral cancer, presents with varied histopathological features based on the degree of differentiation. Keratinizing islands of dysplastic squamous epithelial cells & a dense inflammatory response form the major component of well differentiated SCC. This keratin component may sometimes trigger foreign body giant cell (FBGC) reaction in the stroma, which may mislead the pathologist to aggressive forms of SCC containing pleomorphic giant cells. We encountered such an interesting case of foreign body giant cell reaction in oral SCC. Thus, the present article aims to provide a thorough knowledge on FBGC including their appearance, pathogenesis & significance in oral SCC. How to cite this article: Patil S, Rao RS, Ganavi BS. A Foreigner in Squamous Cell Carcinoma!. J Int Oral Health 2013;5(5):147-50.

The museum maze in oral pathology demystified-part I.

Museum technologies provide a wide array of choice of museums to those who wish to exploit technology to attract, excite and ensure an unrivalled visitor experience, as well as capture and sustain share of mind and heart. Museum being a combination of both art and science requires skilled workmanship, meticulous planning and execution to exhibit a specimen to its optimal elegance due to its relatively smaller size and fragile nature. A well established oral pathology museum is rarely seen due to negligence of oral specimens, dearth of knowledge in this field and also available data on it. An insight on oral pathology museum, including its establishment, importance and advanced technologies to make it more simple and accessible are discussed in two parts. Part I emphasizes on basics in oral pathology museum, whereas part II highlights the specialized techniques and recent advances in museum technology. Our effort is to present this article as hands on experience for the pathologists, student population and the technicians.