Several subtypes of the interstitial cells of Cajal (ICC) form networks that play a role in gastrointestinal motor control. ICC express c-kit and depend on signaling via Kit receptors for development and phenotype maintenance. At 7-8 weeks of development, c-kit-immunoreactive (c-kit-IR) cells are present in the human oesophagus, stomach and proximal duodenum wall. In the remaining small and large bowel, c-kit-IR cells appear later. The object of the present study is to determine the timing of the appearance of c-kit-IR ICC in the parts of the digestive tube originating from the midgut (distal duodenum, jejunum, ileum and proximal colon). Specimens were obtained from eight human embryos and 11 fetuses at 7-12 weeks of gestational age. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. The differentiation of enteric neurons and smooth muscle cells was immunohistochemically examined by using anti-PGP9,5 and anti-desmin antibodies, respectively. In the distal duodenum, jejunum and ileum, c-kit-IR cells emerged at week 9 at the level of the myenteric plexus in the form of a thin row of cells encircling the inception of the ganglia. These cells were multipolar or spindle-shaped with two long processes and corresponded to the ICC of the myenteric plexus. In the proximal colon, c-kit-IR cells emerged at week 9-10 in the form of two parallel belts of cells extending at the submucosal plexus and the myenteric plexus levels. We conclude that ICC develop following two different patterns in the human midgut.
At the end of the embryonic period of human development, interstitial cells of Cajal (ICC) are present in the esophagus, stomach, and proximal duodenum, around the inception of the myenteric plexus (MP) ganglia. In the small and large bowel, ICC appear later. The object of the present study was to determine the timing of appearance and pattern of distribution of ICC in the human embryonic and fetal distal colon. Human distal colon specimens were obtained from 8 embryos and 14 fetuses without gastrointestinal disorders. The specimens were 7–16 weeks of gestational age. The specimens were exposed to anti-c-kit antibodies to investigate ICC differentiation. Enteric plexuses were immunohistochemically examined using anti-neuron-specific enolase, and the differentiation of smooth muscle cells was studied with anti-desmin antibodies. In the distal colon, ICC emerged at weeks 10–11 of the fetal period in the form of two parallel belts of densely packed cells extending at the submucous plexus (SMP) and the MP level. These cells correspond to ICC of the SMP (ICC-SMP) and ICC of the MP (ICC-MP). The simultaneous appearance of ICC at the SMP and MP level in the distal colon can be explained by the fact that there are differences in the migration of neural crest cells in particular portions of the digestive tube. In conclusion, in humans, there was a difference in the patterns of development of ICC in the distal colon compared to the rest of the gut.
The application of "histochemical" staining procedures has been substantially replaced by immunostaining of specific molecular tissue components. The limited range of colors resulting from routine immunohistochemistry, however, can limit assessment of the general microscopic tissue organization. Consequently we have adapted a polychromatic histochemical counterstaining procedure based on Movat's pentachrome staining sequence for use with immunohistochemical procedures. The value of Movat's original method when applied as an immunohistochemical counterstain is limited by its use of iron hematoxylin and by fact that the resulting color combination is difficult to distinguish from the colors of routine immunohistochemical staining. Our variant pentachrome stains the same tissue components as Movat's stain; however, owing to a modification of the acid fuchsin staining step, it provides a strong color contrast with the reaction product resulting from immunostaining using diaminobenzidine as the chromogen. Multicolor counterstaining for immunohistochemistry offers a new approach to tissue analysis, especially when stromal-epithelial relations of normal and neoplastic tissues are considered.
The aim of this study was to evaluate the effect of Na-EDTA and NaOCl in mineral contents in root dentine using SEM and EDS. Material and method: Twenty-two specimens of the middle radicular third obtained from human first molars, extracted for orthodontic reasons, were examined. Specimens were polished and divided into four groups. The first group was treated with saline and used as control. The second group was treated with Na-EDTA for one minute, followed by saline irrigation. The third group was treated with combination of Na-EDTA and NaOCl and the last, fourth group was treated with NaOCl only. Results have shown that Na-EDTA combined with NaOCl as the final flush and NaOCl alone, have significantly influenced changes in the Ca/P ration of the root dentine. The use of NaOCl as the final flush altered the effectiveness of chelating agents in root dentine.
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