Morphometric parameters of dental pulp in immature teeth in a sheep model after mechanical pulp exposure and restoration with reinforced zinc oxide-eugenol.

Background: The aim of the study was to investigate the morphometric parameters of dental pulp in open apices immature teeth in a sheep model after mechanical pulp exposure and restoration with reinforced zinc oxide-eugenol. Materials and Methods: In this experimental study, a total of 12 immature mandibular central incisors from six adult male sheep, weighing 30-40 kg and with the age of 1 year old with Merino race were examined. After anesthesia, the pulps of the teeth in the case group were mechanically exposed and then were restored with reinforced zinc oxide-eugenol and amalgam. In the control group, the teeth remained intact. The animals were sacrificed at intervals of 2, 4, 6, and 8 weeks (E2, E4, E6, and E8) in the case and 2 and 8 weeks (C2 and C8) in the control groups. Then, their teeth were removed with the surrounding supporting tissues and alveolar bones. Tissue processing and staining were done, and the sections were examined under a light microscope. The Kruskal-Wallis and Mann-Whitney U tests were used to analyze the data and compare the changes between the two groups. P < 0.05 was considered statistically significant. Results: In response to mechanical exposure, reparative or tertiary dentin was formed, and its thickness increased during the time of the study. The thickness of the odontoblastic layer in the E4 group was the highest amount. The pulp chamber diameter in the C2 group was significantly larger than the other groups, and the diameter of the apical foramen in the E8 was decreased significantly compared to the controls (P < 0.05). Conclusion: In response to mechanical exposure and restoration with reinforced zinc oxide-eugenol, some morphometric parameters of the dental pulp changed significantly in the sheep model compared to the controls.

Reduced volumetric parameters of the placenta and extravillous trophoblastic cells in complicated pregnancies may lead to intrauterine growth restriction and small for gestational age birth.

AIM: We undertook this study to determine quantitative changes of the placenta, focusing on extravillous trophoblastic cells (EVTs) in pregnancies with intrauterine growth restriction (IUGR) and small for gestational age (SGA) compared to the control group. METHODS: Placentas from pregnancies complicated with SGA-IUGR (n = 10) and control group (n = 10) were obtained after cesarean surgery and evaluated using stereological assays after routine tissue processing and Masson's trichrome staining. Mann-Whitney U-test was employed, and the level of statistical significance was set at p <0.05. RESULTS: Our results showed that the volumetric parameters, including the total volume and volume density of chorionic villi, intervillous spaces, blood vessels in chorionic villi, and syncytiotrophoblast, decreased significantly in the SGA-IUGR group compared to control placentas (p <0.05). Also, total volume, number of EVTs, volume, the diameter of cytoplasm, and diameter of the nucleus in these cells were significantly lower in the SGA-IUGR group (p <0.05). In addition, the nucleus to cytoplasm ratio of EVTs was also higher in the SGA-IUGR group (p <0.05). CONCLUSIONS: There are several significant histological and stereological differences in the placenta, particularly its EVTs from the SGA-IUGR group compared to the control group. It seems that histological changes in the placental tissues could be helpful for the retrospective explanations of pregnancy complications.

Effects of gestational diabetes mellitus on stereological parameters and extravillous trophoblast cells of placenta compared to the control group.

The quantitative changes of extravillous trophoblast cells (EVTs) in placenta of gestational diabetes mellitus (GDM) patients were investigated compared to healthy controls using stereological methods. The volumetric parameters of the placenta and EVTs were estimated using Cavalieri's principle and Physical Disector stereological methods. The placental volume and weight in the GDM group increased compared to the control group (p < .05). The difference in the total volume of intervillous space and blood vessels of the placenta between GDM and control groups was statistically significant (p < .05). In addition, there was a significant difference in the volume density of blood vessels and syncytiotrophoblast between the GDM group and the control group (p < .05). The total volume of the EVTs, nucleus and cytoplasm diameter, volume of the nucleus and cytoplasm, nucleus to cytoplasm ratio (N/C) of EVTs and the total number of EVTs per unit volume of the placenta in the GDM group showed a significant increase compared to the controls (p < .05). Impact statement What is already known on this subject? It is reported that extravillous trophoblast cells (EVTs) played an important role in pregnancy complications. There are limited studies on the quantitative changes of EVTs in the placental bed of GDM patients. What do the results of this study add? The results showed that volumetric parameters and number of EVTs were significantly altered in GDM placentas. These changes can be associated with disturbances in trophoblastic invasion in GDM pregnancies and may affect the development and survival of the embryo. What are the implications of these findings for clinical practice and/or further research? In the present study, there is a new insight to placenta structure that probably could be useful to understanding possible mechanisms of pregnancy complications and the achievement of new therapeutic strategies. Further investigation on the molecular biology of these cells in pregnancy complications will be needed to clarify this hypothesis.

Quantitative changes of gastric mucosa during carcinogenesis using stereological methods.

PURPOSE: To investigate the effects of helicobacter pylori (H. pylori) infection on the quantitative changes of gastric mucosa in cancerous and precancerous lesions using stereological methods. METHODS: One hundred and twenty-two gastric samples were studied. After determination of H. pylori infection, 42 gastric tissues of intestinal metaplasia (IM) patients, 38 specimens from dysplasia (DYS), and 42 specimens from gastric cancer (GC) types were selected from the pathology archive of Imam Ali Hospital, Zahedan, Iran. Gastric tissues were sectioned and stained with p53 and Ki-67 immunohistochemical (IHC) method and haematoxylin/eosin (H&E). Then, the numerical density (NV) of p53-positive, Ki-67-positive cells, eosinophil and polymorphonuclear (PMN) cells were estimated using dissector counting technique in IM, DYS and GC lesions. RESULTS: In IM, DYS and GC specimens, the NV of p53-positive cells in the presence of H. pylori infection (H. pylori+) was significantly higher than in H. pylori absence (H. pylori-). The NV of Ki-67- positive cells only in DYS specimens, showed significant difference between H. pylori+ and H. pylori- groups. The NV of eosinophil cells in DYS and GC specimens in H. pylori+ groups were significantly higher than in H. pylori- groups and the NV of polymorphonuclear cells in IM specimens showed significant difference between H. pylori+ and H. pylori- groups. CONCLUSION: The results showed that H. pylori infection could cause significant quantitative changes in the cellular structure of gastric mucosa that might be influential on gastric carcinogenesis.