Biomedical subjects

Kleoniki Lyroudia

Publications and source records attributed to Kleoniki Lyroudia.

6 recordsLinked to original sources

PubMed2006

Comparative evaluation of neural tissue antigens--neurofilament protein (NF), peripherin (PRP), S100B protein (S100B), neuron-specific enolase (NSE) and chromogranin-A (CgA)--in both normal and inflamed human mature dental pulp.

The immunohistochemical detection of neurofilament protein (NF), peripherin (PRP), S100B protein (S100B), neuron-specific enolase (NSE) and chromogranin-A (CgA) has been studied in nerve fibres and bundles of human dental pulp. This was done in order to identify possible differences in the distribution pattern of the above markers between normal and inflamed pulp and, further, to evaluate their potential use as peripheral markers of dental innervation as well as objective markers for the determination of the extent of inflammation. Both normal and inflamed human dental pulp showed positive immunolabelling for NF, S100B and NSE and lack of labelling for PRP and CgA protein. An increased density of NF, S100B and NSE immunoreactive nerve fibres was observed in inflamed pulp samples compared to non-inflamed. The findings of this study suggest the possible application of NF, S100B and NSE as markers of dental innervation. Furthermore, they may be useful for the determination of the extent of pulpal inflammation, and might be utilized in alternative modalities of biological pulp therapy to reduce the inflammation process. The absence of CgA immunolabelling implies the presumptive absence of neuroendocrine antigens, while further research is required in order to clarify the involvement of PRP in dental pulp.

Adult↗

PubMed2006

A new methodology for the comparative study of the root canal instrumentation techniques based on digital radiographic image processing and analysis.

OBJECTIVE: The objective of this study was to evaluate the utility of digital image processing and analysis procedures for the study and comparison of the efficiency of 2 root canal instrumentation techniques. STUDY DESIGN: Forty mandibular incisors with a single canal were randomly divided into 2 groups of 20 teeth. A step-back technique was followed for the instrumentation of the root canals of Group 1 teeth using hand stainless steel Hedström files (Dentsply Maillefer, Switzerland), while a crown-down technique using ProFile engine-driven nickel-titanium instruments (Dentsply Maillefer) was followed for the instrumentation of the Group 2 root canals. Radiographs of each tooth were taken in bucco-lingual and mesio-distal projections, both before and after instrumentation, under constant conditions and by using a direct digital intraoral radiography system. The postoperative radiographs were digitally subtracted from their respective preoperative radiographs. A contrast enhancement process was applied to the resultant digital subtractive images. The enlargement of the root canals created by each instrumentation technique regarding the apical 6 mm was assessed through the application of region segmentation and area measurement processes. RESULTS: Using this methodology no significant difference between the 2 preparation techniques was found in terms of configuration and enlargement of the root canals. CONCLUSIONS: The application of this methodology provided the ability to (1) visualize dentin lost during root canal instrumentation, (2) simultaneously compare root canal morphology before and after instrumentation, and (3) quantitatively evaluate the enlargement of the root canal area induced by each of the instrumentation techniques.

Dental Pulp Cavity↗

PubMed2006

Visualisation of human dental pulp vasculature by immunohistochemical and immunofluorescent detection of CD34: a comparative study.

CD34 is considered a pan-endothelial cell marker for paraffin-embedded sections. In this study, both immunohistochemistry and immunofluorescence were applied in human dental pulp specimens of moderate thickness (10 microm) in order to observe the vasculature of this tissue using CD34. Both techniques revealed a homogenous staining pattern with capillaries and larger vessels showing complete and strong membrane staining reflecting the high capacity of the pulp for regeneration and response to different stimuli. A novel approach in the identification of the pulpal vasculature by Cy5-conjugated anti-CD34 is introduced in this study. By this technique the dense capillary plexus of the sub-odontoblastic region, which is responsible for the reaction of the tissue to any physical or chemical stimuli or pathological condition, can be clearly identified, while immunohistochemistry did not reveal such a detailed staining pattern.

Adolescent↗

PubMed2005

Automated evaluation of Her-2/neu status in breast tissue from fluorescent in situ hybridization images.

The evaluation of fluorescent in situ hybridization (FISH) images is one of the most widely used methods to determine Her-2/neu status of breast samples, a valuable prognostic indicator. Conventional evaluation is a difficult task since it involves manual counting of dots in multiple images. In this paper, we present a multistage algorithm for the automated classification of FISH images from breast carcinomas. The algorithm focuses not only on the detection of FISH dots per image, but also on combining results from multiple images taken from a slice for overall case classification. The algorithm includes mainly two stages for nuclei and dot detection respectively. The dot segmentation consists of a top-hat filtering stage followed by template matching to separate real signals from noise. Nuclei segmentation includes a nonlinearity correction step, global thresholding to identify candidate regions, and a geometric rule to distinguish between holes within a nucleus and holes between nuclei. Finally, the marked watershed transform is used to segment cell nuclei with markers detected as regional maxima of the distance transform. Combining the two stages allows the measurement of FISH signals ratio per cell nucleus and the collective classification of cases as positive or negative. The system was evaluated with receiver operating characteristic analysis and the results were encouraging for the further development of this method.

Algorithms↗

PubMed2004

Digital radiograph registration and subtraction: a useful tool for the evaluation of the progress of chronic apical periodontitis.

The purpose of this study was to evaluate the suitability of a digital radiograph registration and subtraction software for a sensitive and reliable assessment of the progress of chronic apical periodontitis. Ninety cases of teeth with chronic apical periodontitis have been studied. In each case, a preoperative radiograph was taken, root canals were prepared, and a Ca(OH)2 paste was placed in the root canals. Radiographic control and replacement of Ca(OH)2 paste took place at 15-day intervals. The root canals were obturated 1.5 months after the first appointment. Recall radiographs were taken 0.5, 1.5, 3, 6, and 12 months after the obturation. All radiographs were taken for each case under constant conditions by using a direct digital radiography system. In each case, the preoperative, postoperative, and control and recall radiographs were digitally registered and pairwise subtracted. The resulting images were further processed by using contrast enhancement and pseudocoloring methods. Changes to the periapical tissue structure were easily detectable by using the above-mentioned methodology, even during short time intervals.

Calcium Hydroxide↗

PubMed2002

Virtual endodontics: three-dimensional tooth volume representations and their pulp cavity access.

The purpose of this study was the application of both digital three-dimensional image processing and virtual reality techniques in endodontics. Three-dimensional volume representations of 2 teeth from each tooth category, 16 teeth in total, have been reconstructed. All teeth were embedded in polyester resin, and serial cross-sections 0.75-mm thick were taken from each tooth by using a special microtome. Each section was studied under a stereoscopic microscope, and its microscopic image was directly digitized using a video-camera. The surfaces of hard dental tissues were segmented from each section. Semiautomatic alignment and frame interpolation were performed on the sequence of tooth sections by using appropriate digital image processing techniques. Three-dimensional volume representations from each tooth were achieved in this project to produce the final three-dimensional teeth models, on which virtual accesses of pulp cavities have been performed. Three-dimensional teeth volume representations and virtual tooth "drilling" could serve as perfect educational tools under certain circumstances.

Anatomy, Cross-Sectional↗