In the present study, we describe the structure and normal development of the zebrafish (Danio rerio) paired fins. Particularly, we focus on the structure of the apical epidermis and on endoskeletal morphogenesis. Endoskeletal development proceeds differently in the pectoral and pelvic fins. Whereas in both fins major parts of the endoskeletal girdle develop within the fin bud mesenchyme, the p...

The hippocampus is an ideal system to study synaptic plasticity in the context of learning and memory. The induction, expression, and interaction of long-term potentiation (LTP) as well as long-term depression (LTD) are essential elements for the functioning of complex networks in information processing and storage. Here we investigated whether different loci at the apical dendritic branch of C...

The aim of the present study was to assess the presence of apically extruded debris and evaluate the influence of canal curvature on the amount of debris produced by manual and mechanical techniques. Forty single-rooted mature teeth with 15 to 30 degree of root canal curvature were selected. The presence of only one foramen was confirmed using a magnifying lens. A size 15 K-file was placed up t...

The efficacy of tactile detection of the apical constriction in flared and nonflared root canals was examined in 120 root canals of adult patients. In 68 nonflared (group 1) root canals, a #15 or #20 K-file was used to detect ("feel") the apical constriction. In 52 teeth (group 2), Hedstrom files, Gates Gliden drills #2 to #4, and ultrasonic files were used to enlarge the canal orifice and flar...

PURPOSE Primary spontaneous pneumothorax (PSP) occurs subsequent to a disruption in the continuity of visceral pleura and escape of air into the pleural space. The cause of PSP is most often the rupture of subpleural blebs or bullae. It is usually difficult to detect evidence of pulmonary pathology. The purposes of the present study were (1) to investigate the changes of pulmonary alveolar epit...

AIM To determine the position and shape of the apical foramina in posterior teeth derived from an Indian population. METHODOLOGY A total of 800 freshly extracted maxillary and mandibular premolar and molar teeth from a native Haryana population were collected. Apices of teeth were stained with methylene blue and then examined stereomicroscopically (40x). The following observations were made: ...

Achieving apical foramen patency through surgical maneuvers during the biomechanical preparation of root canals is a goal sought by several schools. The aim of this study was to evaluate the deformation of the foramen as a result of using stainless steel hand files and nickeltitanium rotary instruments for achieving patency. Forty recently extracted dental roots with single canals were calibrat...

INTRODUCTION The purpose of this study was to compare the accuracy of the Root ZX II Apex Locator (RZX), the Elements Apex Locator (ELE), and the Precision Apex Locator (PAL). METHODS Forty single-rooted extracted teeth were decoronated and the root canals coronally flared. Actual canal lengths were determined by inserting a #10 file until the tip was visualized (12.8x magnification) just wit...

The electrical potentials across the cell membranes of the lower parts of Zea mays coleoptile cells are about 2 millivolts more negative than across the upper parts. This electrical polarization with respect to gravity occurs when coleoptiles are oriented with their apical ends either up or down and seems independent of the magnitude of the potential when the potential is modified by other trea...