Nurullah Keklikoglu

iNOS Expression in Oral and Gastrointestinal Tract Mucosa

It is known that the overproduction of nitric oxide (NO) by nitric oxide synthase (NOS) occurs during the progression of various inflammatory diseases in intestinal tract. NOS inhibitors or inducible nitric oxide synthase (iNOS) gene expression inhibitors should be considered as potential anti-inflammatory agents, as NO synthesized by iNOS is related to various pathophysiological processes including inflammation. In order to understand the relationship between iNOS and pathological reactions such as the inflammatory process and malign transformation clearly, the existence and amount of constitutive expression should be determined. It is crucial to comprehend the harmful and protective amounts of iNOS expressions in order to clarify the relationship between iNOS and pathological processes. Evidently, only after this inspection is it possible to utilize iNOS as a marker and treatment instrument during the diagnosis and treatment of malign transformation and the inflammatory process.

Inducible nitric oxide synthase immunoreactivity in healthy rat pancreas.

Nitric oxide (NO) is produced by NO synthase (NOS) isoforms: neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). It is believed that, while nNOS and eNOS are effective in regulation of normal physiological processes, iNOS is expressed at an increasing rate especially in inflammatory process. The aim of this study was to determine the presence of iNOS immunoreactivity (iNOS-IR) and, to compare the iNOS-IR in islet of Langerhans cells (LC), acinar cells (AC), centroacinar cells (CC) and ductal cells (DC) by immunohistochemical (IHC) method in healthy rat pancreata. This study revealed the presence of iNOS-IR in all cell types except AC. Statistical analysis revealed a highly significant difference (p<0.001) with respect to iNOS-IR in comparison of all cell types. However, binary comparison of cell types revealed no significant differences between LC and DC (p=0.136), significant differences LC and CC, CC and DC (p=0.001 and 0.022, respectively) and a highly significant differences LC and AC, AC and DC (P<0.001). The results of this study indicate that iNOS-IR is present in almost all LC. Thus, especially in reseach related to diabetes, it should not be disregarded that iNOS may be constitutively present in pancreatic islets.

Comparison of three different techniques for histological tooth preparation

The histological processing of teeth is highly complicated because of containing both mineralized hard tissues and soft tissues. Depending on the type of decalcification agents used in processing, mild-to-severe deterioration in the tissue structure and inadequacies on clear staining of details by the histological stain may be observed. This study aims to compare the histological staining differences in the preparations from decalcified and undecalcified tooth roots by three different embedding materials and techniques. Following extraction, human single-rooted teeth crowns were cut off and roots were placed in 10% buffered neutral formalin. After fixation, roots were divided into two groups. One part of samples was decalcified in formic acid solution and the other was remained undecalcified. Decalcified roots were embedded in paraffin and glycol methacrylate (GMA)-based resin and undecalcified roots were embedded in methyl methacrylate (MMA)-based resin. Sections from all groups were stained with hematoxylin and eosin. The groups were compared in terms of general staining, brightness, density, density of the base stain, general morphology of cells, nuclear/cytoplasmic contrast, distinguish ability of pulp, odontoblast layer, predentin and dentin, preservation and traceability of dentinal tubule. In the preparations which were embedded into the MMA-based embedding material, an output lower than the paraffin group buthigher than the GMA-embedded group was provided. As a result, the best histological detail was obtained from the decalcified, paraffin-embedded sections.

Immunoreactivity of ATF-2 and Fra-2 in human dental follicle.

It is asserted that epithelial rests in dental follicle (DF) existing around the impacted teeth in adults are effective in cyst formation. In this study, it is intended for determining and comparing the immunoreactivity (IR) ratio of ATF-2 and Fra-2 proteins, the members of Activator Protein-1 (AP-1) family which regulates important cellular activities such as growth, proliferation and differentiation, in DF epithelial cells (EC) and connective tissue cells (CC). In this study, ATF-2 and Fra-2 immunoreactivity (ATF-2-IR and Fra-2-IR) in EC and CC in DF tissues obtained from 30 patients were analyzed by using immunohistochemical method. Ratios of ATF-2-IR positive cells were found 17.36+/-9.55% in EC, 27.27+/-14.86% in CC and ratios of Fra-2-IR positive cells were found 20.04+/-11.47% in EC, 16.71+/-9.05% in CC. In the statistically comparison performed; significant differences were found between EC and CC in terms of both ATF-2-IR (p<0.001) and Fra-2-IR (p<0.05). In EC, no significant difference was found between ATF-2-IR and Fra-2-IR (p>0.05), whereas significant difference was found between ATF-2-IR and Fra-2-IR in CC (p<0.001). According to these data, it can be suggested that Fra-2 protein may be more effective than ATF-2 protein in cyst formation originated from EC of DF. Besides, finding that ATF-2-IR and Fra-2-IR are different in CC although similar in EC shows that AP-1 members can be expressed at different ratios in same tissues.

c-Jun, Fra-2, and ATF-2 Immunoreactivity in the Jejunal Tissues of the Healthy Rat

The aim of this study was to compare the localization of some activator protein-1 (AP-1) proteins in healthy rat jejunum. For this purpose, the AP-1 members c-Jun, Fra-2, and ATF-2 immunoreactivity (c-Jun-IR, Fra-2-IR, ATF-2-IR) in villus epithelial cells (ECs), intravillous lamina propria cells (LPCs), crypt cells (CCs), and smooth muscle cells (SMCs) were analyzed by immunohistochemical methods. Among all the cell groups, the lowest positivity ratio was found in c-Jun-IR and the highest positivity ratio was found in ATF-2-IR. For each group of ECs, LPCs, CCs, and SMCs, c-Jun-IR, Fra-2-IR, and ATF-2-IR were compared and statistically significant differences found. There were no significant differences among the cell groups with respect to c-Jun-IR and Fra-2-IR, but there was a statistically significant difference in ATF-2-IR. These findings suggest that each member of AP-1 is expressed differently and that ATF-2 is more active than c-Jun and Fra-2 in physiological conditions in healthy rat jejunum.

Immunolocalization of c-Fos, c-Jun and Fra-2 in healthy human marginal gingival tissues

Background and Objective: Keeping marginal gingiva healthy is possible with some cellular processes. Activator Protein-1 (AP-1) members Fos and Jun proteins regulate cellular processes including growth, proliferation, differentiation and apoptosis. The aim of this study was to compare of immunoreactivity (IR) of some same or different family member AP-1 proteins in cells forming marginal gingival mucosa. Materials and Methods: IR of Fos family members c-Fos (c-Fos-IR) and Fra-2 (Fra-2-IR) and Jun family member c-Jun (c-Jun-IR) were analysed in epithelial cells (ECs) and lamina propria cells (LPCs) of healthy human marginal gingiva by immunohistochemical method. Results: Both in ECs and LPCs, c-Fos-IR positivity was found higher than the others and Fra-2-IR positivity was found lower. The most postivity was observed in c-Fos-IR in ECs and the least IR was observed in Fra-2-IR in LPCs. Furthermore, the IR positivity percentage of all proteins was found higher in ECs than in LPCs. In the comparision of each of c-Fos-IR, c-Jun-IR and Fra-2-IR in ECs and LPCs, no statistically significant difference in c-Jun-IR was observed; however, there were statistically significant differences in c-Fos-IR and Fra-2-IR. Conclusions: According to these findings, it can be proposed that c-Fos protein in healthy gingiva is more related with physiological processes than other proteins. In this study, establishing a statistically significant difference between c-Fos-IR and Fra-2-IR in both ECs and LPCs has shown that as well as these proteins are within the same family, each one may be related with different cellular processes.