Spectrum, Applicability and Diagnostic Capacity of Contrast-Enhanced Ultrasound in Pediatric Patients and Young Adults after Intravenous Application - A Retrospective Trial

Purpose: To investigate the spectrum, applicability and diagnostic capacity of intravenous contrast-enhanced ultrasound imaging (CEUS) in a pediatric population. Materials and Methods: From 08/2005 to 11/2015, n = 40 pediatric patients and young adults from 0 - 26 years (Ø 11.4 ± 7.5) and 3.0 - 85.3 kg (Ø 40.8 ± 25.6) with n = 55 investigations received n = 79 IV applications of ultrasound contrast agent (UCA). UCA dose and side effects were documented. Scanned organs were the liver (n = 42), spleen (n = 9), kidney (n = 3), and testis (n = 1). Histology, surgery or reference imaging was compared to CEUS and clinical follow-up. Results: The UCA dose < 20 kg was 0.4 ± 0.3 ml, (0.05 ± 0.02 ml/kg) and > 20 kg was 1.0 ± 0.4 ml (p< 0.0001) (0.02 ± 0.01 ml/kg, p< 0.0001). Adverse effects occurred in 2/79 applications (2.5 %). Agreement CEUS/gold standard resulted in 32/34 investigations. For liver diagnostics (gold standard: MRI, CT, histology, serology), n = 11 malignant and n = 15 benign focal liver lesions were included. The specificity was 100 % (95 % CI: 0.77 - 1.00), the sensitivity was 82 % (95 % CI: 0.48 - 0.98), the positive predictive value was 100 % (95 % CI: 0.69 - 1.00) and the negative predictive value was 88 % (95 % CI: 0.62 - 0.98, p< 0.0001). In n = 2 reference imaging misdiagnosed and CEUS was in accordance with clinical follow-up. All splenic/renal lesions were diagnosed correctly. In n = 1 an insufficient testicular perfusion was ruled out. The observation time was 30.4 ± 30.5 months. Conclusion: CEUS is a well-tolerated and diagnostically equivalent modality in pediatric care, providing fundamental advantages compared to currently approved imaging modalities for these age groups.

The tumor suppressor gastrokine-1 is expressed in placenta and contributes to the regulation of trophoblast migration

INTRODUCTION

Gastrokine-1 (GKN1) is a secreted auto-/paracrine protein, described to be expressed in the gastric mucosa. In gastric cancers GKN1 expression is commonly down-regulated. While current research focusses on the exploration of tumor-suppressive properties of GKN1 with regard to its potential clinical use in the treatment of gastroenterologic tumor disease, nothing is known about GKN1 expression and function in other organ systems. We investigated GKN1 expression in placental tissue and cells.

MATERIALS AND METHODS

GKN1 was localized using immunohistochemistry in first and third trimester placental tissue, hydatidiform moles and various gestational trophoblastic neoplasias. We determined the expression of GKN1 in immunomagnetic bead-separated term placental cells and in choriocarcinoma cell lines. The role of GKN1 for JEG-3 migration was studied using live cell imaging. E-cadherin, MMP-2 and -9, TIMP-1 and -2, as well as urokinase (uPA) expression levels were determined.

RESULTS

GKN1 is expressed in healthy third trimester placentas. Its expression is specifically limited to the extravillous trophoblast (EVT). GKN1 expression is significantly reduced in choriocarcinoma cell lines and gestational trophoblastic neoplasias. GKN1 attenuates the migration of JEG-3 choriocarcinoma cells in vitro, possibly via AKT-mediated induction of E-cadherin. GKN1 treatment reduced MMP-9 expression in JEG-3.

DISCUSSION

Besides its role in gastric physiology our results clearly indicate regulatory functions of GKN1 in the EVT at the feto-maternal interface during pregnancy. Based on our findings in the JEG-3 choriocarcinoma cell line, an auto-/paracrine role of GKN1 for EVT motility and villous anchorage at the basal plate is conceivable. Thus, the tumor suppressor GKN1 is expressed in placental EVT and might contribute to the regulation of EVT migration/invasion.