Synthetic MRI in Neurofibromatosis Type 1

BACKGROUND AND PURPOSE:Synthetic MRI enables the generation of various contrast-weighted images and quantitative data in a reasonable scanning time. We aimed to use synthetic MRI to assess the detection and underlying tissue characteristics of focal areas of signal intensity and normal-appearing brain parenchyma and morphometric alterations in the brains of patients with neurofibromatosis type 1.MATERIALS AND METHODS:Conventional MR imaging and synthetic MRI were prospectively obtained from 19 patients with neurofibromatosis type 1 and 18 healthy controls. Two neuroradiologists independently evaluated focal areas of signal intensity on both conventional MR imaging and synthetic MRI. Additionally, automatically segmented volume calculations of the brain in both groups and quantitative analysis of myelin, including the focal areas of signal intensity and normal-appearing brain parenchyma, of patients with neurofibromatosis type 1 were performed using synthetic MRI.RESULTS:The comparison of conventional MR imaging and synthetic MRI showed good correlation in the supratentorial region of the brain (κ = 0.82–1). Automatically segmented brain parenchymal volume, intracranial volume, and GM volumes were significantly increased in the patients with neurofibromatosis type 1 (P < .05). The myelin-correlated compound, myelin fraction volume, WM fraction volume, transverse relaxation rate, and longitudinal relaxation rate values were significantly decreased in focal areas of signal intensity on myelin and WM maps (P < .001); however, GM, GM fraction volume, and proton density values were significantly increased on the GM map (P < .001).CONCLUSIONS:Synthetic MRI is a potential tool for the assessment of morphometric and tissue alterations as well as the detection of focal areas of signal intensity in patients with neurofibromatosis type 1 in a reasonable scan time.

Neuroimaging plays an important role in the diagnosis and follow-up of neurofibromatosis type 1 (NF-1). The most common parenchymal abnormality of the brain in NF-1 is oval or round focal areas of abnormal signal intensity (FASI), mainly in the basal ganglia, cerebellum, and brain stem on T2WI. These lesions do not show enhancement with gadolinium or mass effects.¹ Additionally, studies in Drosophila species and mice with NF1 gene mutations have shown progressive myelin (MY) defects and behavioral abnormalities in a neurofibromin 1 dose-dependent fashion.^2-4 Although evidence is inconclusive, vacuolar changes in myelin, defined as fluid-containing spaces ranging from 5 to 100 mm, have been suggested to explain the FASI.^5,6The synthetic MRI (SyMRI) sequence, called quantification of relaxation times and proton density by multiecho acquisition of a saturation-recovery (QRAPMASTER) using turbo spin-echo readout,⁷ enables automatic segmentation of brain tissue and measurement of myelin-based quantitative values with good accuracy and reproducibility in approximately 6 minutes with full head coverage.⁸ This sequence has had encouraging results for brain metastasis, multiple sclerosis, meningitis, idiopathic normal pressure hydrocephalus, and Sturge-Weber syndrome in several studies and has been approved by the FDA.^8-12In this study, we aimed to detect and evaluate FASI and examine morphometric changes in the brain in patients with NF-1 using SyMRI. We also sought myelin abnormalities in FASI and normal-appearing brain parenchyma (NABP) in patients with NF-1. Because FASI tends to resolve by early adulthood, we intentionally performed this study with pediatric patients.¹³ Our hypothesis was that SyMRI could detect FASI and quantify morphologic and tissue changes in pediatric patients with NF-1.     

Bond strengths of three different dentin adhesive systems to sclerotic dentin

The two-fold aims of this study were: (1) to evaluate the microtensile bond strengths of different adhesive systems to sclerotic and sound palatal dentin; and (2) to observe the respective resin-dentin interfaces. Thirty extracted human incisor teeth were divided into two groups. Group I comprised sclerotic defects in the palatal zone. Group II comprised sound palatal dentin surfaces as control. Each group (n=15) was divided into three subgroups according to dentin adhesive systems: self-etch (Clearfil SE Bond), total-etch (Scotchbond Multi-Purpose Plus), and glass ionomer (Reactmer Bond) adhesive systems. The specimens were subjected to tensile forces. Obtained data were analyzed by two-way ANOVA and post hoc Duncan's test. Fracture sites and resin-dentin interfaces were observed using a light microscope and SEM. With sound dentin, Clearfil SE Bond showed a significantly higher bond strength than the other adhesives (p < 0.05). With sclerotic dentin, although there were no significant differences in bond strength among the adhesives groups (p > 0.05), the bond strength values of Clearfil SE Bond and Scotchbond Multi-Purpose Plus were significantly decreased. On resin-dentin interface observation, different images were presented by different bonding systems.     

The influence of different maternal pushing positions on birth outcomes at the second stage of labor in nulliparous women

Objectives: To assess the effects on neonatal and maternal outcomes of different pushing positions during the second stage of labor in nulliparous women.

Methods: This prospective study included 102 healthy, pregnant, nulliparous women who were randomly allocated to either of two positions: a squatting using bars (n?=?51), or a supine position modified to 45 degree of semi-fowler (n?=?51) during the second stage of labor. Duration of the second stage of labor, maternal pain, postpartum blood loss, abnormal fetal heart rate patterns that required intervention, and newborn outcomes were compared between the two groups.

Results: The trial showed that women who adopted the squatting position using bars experienced a significant reduction in the duration of the second stage of labor; they were less likely to be induced, and their Visual Analog Scale score was lower than those who were allocated the supine position modified to 45 degree of semi-fowler during second stage of labor (p?Conclusions: In healthy nulliparous women, adopting a squatting position using bars was associated with a shorter second stage of labor, lower Visual Analog Scale score, more satisfaction, and a reduction in oxytocin requirements compared with adopting the supine position. For Turkish women, the squatting position is easy to adopt as it is more appropriate in terms of Turkish social habits and traditions.     

Evaluation of internal adaptation in ceramic and composite resin inlays by silicon replica technique

This study was aimed at investigating the internal adaptation of a ceramic (Ceramco II) and two composite resin inlay materials (SureFil and 3M Filtek Z 250) using silicon replica technique as an indicator. Forty-five standard mesial-occlusal-distal (MOD) cavities were prepared into brass moulds by using computer numerically controlled system. Inlays were prepared according to manufacturers' instructions with indirect methods. Replicas of the prepared cavities and inlays were produced with a polyvinyl siloxane material (Elite H-D). The spaces between inlays and cavities were filled by different coloured light-body polyvinyl siloxane material. Two parallel slices (mesio-distally) were obtained from the replicas with a sharp blade. Different coloured polyvinyl siloxane material thickness between cavity and inlay was measured at seven points (mesial, occlusal and distal). The data were evaluated with anova and Tukey's honestly significantly different (HSD) statistical tests. In the SureFil and Ceramco II groups, the sizes of the contraction gaps at mesial and distal gingival floors were greater than that of the occlusal marginal walls. In comparison of gap formation at occlusal regions, while the 3M composite group showed highest gap values (204.33 +/- 75.45 microm), the Ceramco II group revealed the lowest (141.17 +/- 23.66 microm) (P < 0.05). At the gingival floors, gap formation of Ceramco II group was the highest (227.08 +/- 51.95 microm). Neither the 3M Filtek Z250 nor SureFil group showed any statistical difference between gap values of their self-occlusal and gingival floors (P > 0.05). In conclusion, our results showed that ceramic inlays did not confer any big advantage for internal adaptation over the composite inlays.     

The role of Hofbauer cells on the pathogenesis of early pregnancy loss

Introduction

Hofbauer cells (HC) are the placental macrophages that play a significant role in many important placental events. The aim of this retrospective study is to investigate the role of HC in the pathogenesis of early pregnancy loss (EPL).

Methods

The slides were obtained from archival blocks of missed abortion (MA, n = 15) and blighted ovum (BO, n = 15) cases. Unwanted pregnancies materials constituted the control group (n = 15). HC and endothelial cells were identified using immunohistochemical methods. HC were counted under light microscope. The extent of villous vasculature was evaluated using two methods; the Chalkey method and microvessel scoring.

Results

The mean number of villous HC was found to be significantly higher in both MA and BO groups in contrast to the control group. MA group also showed a higher number of HC in comparison with the BO group. Higher microvessel scoring was also found in MA group in contrast to other two groups. Chalkey method revealed no significant difference in the extent of villous vasculature for the control group in comparison with MA and BO.

Discussion

As we identified relatively low quantity of HC in BO associated with defective vasculature, we hypothesize that an inadequate microvessel formation after hypoxic insult can explain the pathogenesis of BO. We believe that HC are increased in MA due to their divergent roles on immunity and inflammation.

Conclusion

We therefore conclude that HC may be of biological importance in the pathogenesis of EPL.