Jae Hyung Park

Pathological roles of the VEGF/SphK pathway in Niemann–Pick type C neurons

Sphingosine is a major storage compound in Niemann–Pick type C disease (NP–C), although the pathological role(s) of this accumulation have not been fully characterized. Here we found that sphingosine kinase (SphK) activity is reduced in NP–C patient fibroblasts and NP–C mouse Purkinje neurons (PNs) due to defective vascular endothelial growth factor (VEGF) levels. Sphingosine accumulation due to inactivation of VEGF/SphK pathway led to PNs loss via inhibition of autophagosome–lysosome fusion in NP–C mice. VEGF activates SphK by binding to VEGFR2, resulting in decreased sphingosine storage as well as improved PNs survival and clinical outcomes in NP–C cells and mice. We also show that induced pluripotent stem cell (iPSC)-derived human NP–C neurons are generated and the abnormalities caused by VEGF/SphK inactivity in these cells are corrected by replenishment of VEGF. Overall, these results reveal a pathogenic mechanism in NP–C neurons where defective SphK activity is due to impaired VEGF levels.

Establishment of normal reference of radiological morphology of renal artery in mini-pigs by renal angiography

Mini-pigs have been widely employed in preclinical studies to explore new therapeutic strategies for diseases of the human urinary system; however, the normal reference of the renal artery has not been clearly investigated in the mini-pig model. Therefore, we aimed to establish a normal reference of the radiological morphology of the renal artery in mini-pigs by renal angiography via catheterization of the carotid artery. The renal angiographies obtained from 15 mini-pigs were evaluated to determine the orifice from the aorta, facing direction, size and the number of branches of renal arteries. Cranio-laterally facing renal arteries with 2 distal branches were mainly observed in the renal artery of mini-pigs. Both sides of the renal artery presented symmetrical sizes; however, the right renal artery orifice from the aorta was located more cranially than the left counterpart. The results of this study will contribute to radiological diagnosis of the renal artery as well as preclinical studies of mini-pigs.

Hepatic Vein Invasion by Hepatocellular Carcinoma: CT Manifestations with Anglographic Correlation

This essay illustrates the various CT findings of the hepatic venous invasion of the hepatocellular carcinoma with an angiographic correlation. The thrombosed hepatic vein is directly visualized as a dilated tubular structure or multiple nodules of the similar attenuation to that of the parenchymal tumor, connecting the parenchymal tumor and the inferior vena cava on contrast enhanced CT scans. Enhancement of the thrombosed vein on spiral CTscans obtained in early arterial phase can suggest thrombosis caused by tumor invasion rather than a simple thrombosis. When the thrombosed hepatic vein is not directly visualized and replaced bya largetumor, thetumorthrombi within the inferior vena cava or right atriu m can suggest the presence of the hepatic venous invasion.

Superselective transcather arterial embolization for hepatocellular carcinoma with a mixture of ethanol and lipiodol

To evaluate the effectiveness of superselective transcatheter arterial embolization (STAE) for hepatocelluar carcinoma (HCC) with a mixture of ethanol and Lipiodol. STAE was done in 12 male patients with HCC. Three were diagnosed clinically with angiographic findings 없ld elevated alphafetprotein levels and three were recurrent tumors after surgery. Sono-guided aspiration biopsy proved the diagnosis of hepatocellular carcinoma in another six patients. The tumor was a small single nodule (2-5cm in diameter) in 11 patients. In one patient. two nodules were found. Superselective catheterization was done using 3F Tracker catheter (Target Therapeutics USA) coaxially through 6F catheter into the feeding hepatic artery. usually the third order branch. One to four cc of 75% ethanol mixed with Lipiodol was infused under f1uoroscopy immediately after imjection of 2% Iidocaine. Immediate angiography and CT after 2 weeks were undertaken . Complete segmental or subsegmental devascularization including feeding arteries and tumor vascularities occurred in all patients. Follow-up angiography after 6 to 15 months revealed the tumor opacified by Lipiod이 . The tumor decreased in 5 cases and recurrence was found in three patients. CT taken 2 weeks after ST AE showed low density halo around the tumor in 5 cases. Subsequest segmentectomy in four patients revealed total or near total necrosis of the tumor and no evidence of damage in surrounding parenchyme. ST AE for HCC with a mixture of ethanol and Lipiodol is an effective and safe measure for small HCC.