Expression of L amino acid transport system 1 and analysis of iodine-123-methyltyrosine tumor uptake in a pancreatic xenotransplantation model using fused high-resolution-micro-SPECT-MRI

BACKGROUND:The specificity in discriminating pancreatitis is limited in the positron emission tomography(PET)using Fluorine-18-fluorodeoxyglucose.Furthermore,PET is not widely available compared to the single photon emission computed tomography(SPECT).Since amino acids play a minor role in metabolism of inflammatory cells,the potential of the SPECT tracer,3-[ 123 I]iodo-L-α-methyltyrosine(123I-IMT),for detecting pancreatic cancer was examined in xenotransplantation models of human pancreatic carcinoma in mice. METHODS: 123 I-IMT was injected to eight mice inoculated with subcutaneous or orthotopic pancreatic tumors.Fused high-resolution-micro-SPECT(Hi-SPECT)and magnetic resonance imaging were performed.The gene expression level of L amino acid transport-system 1(LAT1)was analyzed and correlated with tumor uptake of 123 I-IMT. RESULTS:A high uptake of 123 I-IMT was detected in all tumor-bearing mice.The median tumor-to-background ratio (T/B)was 12.1(2.0-13.2)for orthotopic and 8.4(1.8-11.1)for subcutaneous xenotransplantation,respectively.Accordingly, the LAT1 expression in transplanted Colo357 cells was increased compared to non-malignant controls.CONCLUSIONS:Our mouse model could show a high 123 I-IMT uptake in pancreatic cancer.Fused MRI scans facilitate precise evaluation of uptake in the specific regions of interest.Further studies are required to confirm these findings in tumors derived from other human pancreatic cancer cells.Since amino acids play a minor role in the metabolism of inflammatory cells,the potential for application of 123 I-IMT to distinguish pancreatic tumor from inflammatory pancreatitis warrants further investigation.

The relation between ADHD and ANS-CNS integration

Background: Attention deficit hyperactivity disorder (ADHD) was long considered to be limited to children and adolescents, but it is now known that ADHD symptoms may persist into adulthood. It is plausible that the etiology of ADHD is not one-dimensional, but instead involves various neuroanatomical and neurochemical systems, with the causes of the main abnormalities believed to be catecholaminergic. Iodine-123-labeled meta-iodobenzylguanidine (123I-MIBG) is a physiological analogue of norepinephrine (NE). To the best of our knowledge, there are no reports about the abnormalities of MIBG scintigraphy in patients with ADHD. The cases presented are male adult patients with different comorbid psychiatric disorders. Case presentation: The cases presented are male adult patients with different psychiatric disorders. Case 1 was a 52-year-old male residential construction foreman, who had been diagnosed with acute schizophrenia-like psychotic disorder. 123I-MIBG planar and SPECTs of the studies were performed at 20 min (early phase) and 3 h (late phase) after intravenous injection of 111 MBq. Planar images were processed to determine the heart (H) to mediastinum (M) ratio (H/M). The early and late H/M ratios were 1.22 and 1.07, respectively. Case 2 was a 52-year-old male civil servant who was diagnosed with adjustment disorder. The early and late H/M ratios were 1.98 and 2.08, respectively. Conclusion: Clinical studies make it clear that symptoms of ADHD are more heterogenous and subtle in adults than children. Adult ADHD is significantly commorbid with wide range of other 12-month disorders. MIBG imaging can be useful to diagnose patients with preexisting psychiatric disorders and ADHD. It might be possible to diagnose objectively though the psychiatric statuses resemble or coexist with other psychiatric disorders. Needless to say, further research is important.