Evaluation of quantitative parameters of dynamic contrast-enhanced magnetic resonance imaging in qualitative diagnosis of hepatic masses.

BACKGROUND: To explore the value of parameters of multiphase dynamic contrast-enhanced magnetic resonance imaging (MDCE-MRI) in the qualitative diagnosis of hepatic masses. METHODS: Eighty patients with hepatic masses were retrospectively analyzed. All the patients underwent MDCE-MRI at 3.0 T MR before treatment. Mean enhancement time (MET), positive enhancement integral (PEI), a maximum slope of increase (MSI), and a maximum slope of decrease (MSD) were measured. RESULTS: There were significant differences between benign and malignant hepatic masses with respect to MET, PEI, and MSI values. The PEI and MSI values between hemangiomas, hepatocellular carcinomas (HCCs), cholangiocarcinomas, and metastatic tumors had significant differences. The MSD value between metastatic tumors, HCCs, and hemangiomas were significantly different. The area under the curve (AUC) values of the receiver operator characteristic curves for MET, PEI, and MSI were 0.70, 0.72, and 0.80, respectively. The specificity of MET, PEI, and MSI were all 77%, and the sensitivities of MSI was the highest, of which was 82.40%. Logistic regression analysis showed the regression equation to be P = 1/[1 + e0.008 × 1 + 0.007 × 2-6.707], and taking the Youden index maximum points as a diagnostic point was 0.2946. CONCLUSION: Some parameters of MDCE-MRI have significant roles in differentiating hepatic masses.

Conformation and dynamics of the C-terminal region in human phosphoglycerate mutase 1.

Phosphoglycerate mutase 1 (PGAM1), an important enzyme in glycolysis, is overexpressed in a number of human cancers, thus has been proposed as a promising metabolic target for cancer treatments. The C-terminal portion of the available crystal structures of PGAM1 and its homologous proteins is partially disordered, as evidenced by weak electron density. In this study, we identified the conformational behavior of the C-terminal region of PGAM1 as well as its role during the catalytic cycle. Using the PONDR-FIT server, we demonstrated that the C-terminal region was intrinsically disordered. We applied the Monte Carlo (MC) method to explore the conformational space of the C-terminus and conducted a series of explicit-solvent molecular dynamics (MD) simulations, and revealed that the C-terminal region is inherently dynamic; large-scale conformational changes in the C-terminal segment led to the structural transition of PGAM1 from the closed state to the open state. Furthermore, the C-terminal segment influenced 2,3-bisphosphoglycerate (2,3-BPG) binding. The proposed swing model illustrated a critical role of the C-terminus in the catalytic cycle through the conformational changes. In conclusion, the C-terminal region induces large movements of PGAM1 from the closed state to the open state and influences cofactor binding during the catalytic cycle. This report describes the dynamic features of the C-terminal region in detail and should aid in design of novel and efficient inhibitors of PGAM1. A swing mechanism of the C-terminal region is proposed, to facilitate further studies of the catalytic mechanism and the physiological functions of its homologues.

[Relationship between episodic memory and resting-state brain functional connectivity network in patients with Alzheimer's disease and mild cognition impairment].

OBJECTIVE: To explore the relationship between the scores of episodic memory (EM) encoding and retrieving and the resting-state changes of brain functional connectivity (FC) network of Alzheimer's disease (AD) and mild cognition impairment (MCI) patients. METHODS: All subjects were recruited from special care clinic and ward and health physical examination center, Qingdao Huanxiu Community and Affiliated Hospital, Medical College of Qingdao university from January 2009 to July 2012.They were divided into AD group (n = 16), MCI group (n = 24) and normal control (NC) group (n = 24). The resting-state fMRI scans were performed with GE3.0T to acquire the blood oxygenation level dependent signals for EM encoding and retrieving. The two-sample t test was conducted between the groups and linear correlation analysis performed between EM and FC. RESULTS: Compared to the NC group, the AD and MCI groups exhibited decreased FC to posterior cingulated cortex (PCC) mainly in bilateral lateral temporal lobe, medial prefrontal cortex and right insula.Increased regions existed in posterior cerebellar lobe. Compared with the MCI group, the AD group showed decreased FC to PCC in medial prefrontal cortex, bilateral insulas, right inferior temporal gyrus and right fusiform gyrus.And increased regions lied in posterior cerebellar lobe, right occipital lobe and left superior parietal lobule. Compared with the NC group, the MCI group exhibited decreased FC to PCC in left lingualis gyrus, left frontal lobe, right middle temporal gyrus and corpus callosum.And increased regions lied in posterior cerebellar lobe.EM encoding scores (%) (AD group 34 ± 20, MCI group 47 ± 17, NC group 69 ± 15) were significantly different among three groups (P < 0.05).And retrieving scores (%) (AD group 31 ± 18, MCI group 57 ± 22, NC group 81 ± 16) were significantly different among three groups (P < 0.05). Altered functional connectivity regions of left triangle orbital-inferior frontal gyrus (r = 0.642 98), left cuneus (r = 0.642 98) and left caudate nucleus (r = 0.642 68) showed positive correlations with the EM encoding scores in AD group (all P < 0.005). Other groups were not statistically significant. CONCLUSION: The resting-state FC networks of AD and MCI groups show significant differences. The MCI and AD patients have progressively decreased scores of episodic memory encoding and retrieving.And the declines of episodic memory encoding and partial regions of resting-state FC network are positively correlated in the AD group.

[An experimental study of the cervical lymphatic imaging in interstitial magnetic resonance lymphography of tongue using Dextran-DTPA-Gd].

PURPOSE: To explore the application value of the cervical lymphatic imaging in interstitial magnetic resonance lymphography using submucosal injection of Dextran-DTPA-Gd. METHODS: 0.2 mL Dextran-DTPA-Gd (3.96 mmol/L) was injected into the submucosa of the bilateral lingual margins in 12 New Zealand rabbits,and then massaged the injection site for 30 seconds. MR images were obtained before injection and 10, 15, 20, 25, 30, 35, 40, 50, 90 minutes after injection by 3D TOF CE-MRA sequence.The signal intensities of cervical lymph node were measured, the enhancing rates(E%) were calculated and the signal enhancing rates -time curve was drawn. The data was analysed using SPSS11.5 software package. RESULTS: The cervical lymph nodes,the first and second lymphatics were strengthened significantly after injecting Dextran-DTPA-Gd, but the blood vessels were not enhanced at the same time. The enhancing rates of cervical lymph node reached the peak(344%) at 30-min,and the best strengthening effect was achieved between 20-min and 50-min. CONCLUSIONS: As IMRLG contrast agent,the Dextran-DTPA-Gd could image lymphatic drainage lines of the neck and the cervical lymph nodes efficiently.

Clinical and genetic study of a novel mutation in the REEP1 gene.

OBJECTIVE: To examine the gene mutation associated with clinical phenotype from a Chinese kindred with autosomal dominant hereditary spastic paraplegia (ADHSP). METHOD: To perform linkage analysis and mutation detection. For two affected individual of the family, clinical analysis, electrophysiological examination, and MRI of brain and spinal cord were also performed. RESULT: A novel splice-site mutation (REEP1 c417+1g>a) was identified. Central motor conduction time to the first metatarsal interosseus and anterior tibial muscles were clearly prolonged. Thoracic cord atrophy was found from T1 to T10. CONCLUSION: Our study supports that mutations in REEP1 cause ADHSP and demonstrates genetic heterogeneity in ADHSP. Synapse

Clinical and genetic study of SPG6 mutation in a Chinese family with hereditary spastic paraplegia.

Mutations in the NIPA1 gene cause autosomal dominant hereditary spastic paraplegia (ADHSP). To date, little is known about the relationship between genotype-phenotype correlation. In order to examine the gene mutation associated with the genotype-phenotype of Chinese kindred with ADHSP, linkage analysis and mutation detection were performed. For affected family members, clinical analysis, electrophysiological examination and MRI of the brain and spinal cord were also performed. Every effected patient had a c316 (G106R) mutation in the NIPA1 gene. Neurophysiological examination revealed decreased amplitude of compound muscle action potentials (CMAP) from the tibial and peroneal motor nerves in most patients. Sensory nerve action potential (SNAP) from the tibialis nerve was not elicited in most patients. Central motor conduction time (CMCT) to the abductor pollicis brevis muscle (APB), first metatarsal interosseus muscle (FMI) and anterior tibial muscle (AT) were either absent or clearly prolonged in all patients. Spinal cord MRI showed different levels of atrophy in every affected individual. These lesions present an increased spot or patch signal on transverse axis T2WI and an intense signal of continual longitudinal strip on the anteroposterior axis. Our study supports that mutations in the NIPA1 gene cause ADHSP and further demonstrates genotype-phenotype correlations in SPG6.

[Radiological diagnosis of primary malignant fibrous histiocytoma of bone].

OBJECTIVE: To explore the radiological diagnosis of primary malignant fibrous histiocytoma (MFH) of bone. METHODS: Sixteen patients with biopsy-or surgery-confirmed MFH received both plain X-ray and CT examinations, among whom six patients simultaneously received MRI. The imaging features were analyzed and the differential diagnoses were assessed. RESULTS: (1) Plain X-ray findings: All these lesions showed irregularly osteolytic, accompanied by cortical destruction. Five patients had varied degrees of cortical expansion, 12 had large soft tissue masses adjacent to the lesions, and only 2 had periosteal reaction. (2) CT findings: All lesions were osteolytic areas but had no evidences that its internal architecture had been replaced by soft tissue mass, and the cortical adjacent to the lesions were permeative osteolysis. Four patients had internal or marginal crest within the lesions and marginal inconsecutive osteosclerosis. Twelve had large soft tissue masses but without any calcification and residual architecture adjacent to the lesions, among which 3 patients had solitary or multiple cystic attenuation areas within the masses. No clear periosteal reaction was observed on CT. (3) MRI findings: All of lesions in 6 patients who received MRI showed inhomogeneous long T1 and long T2 abnormal signal intensity with soft tissue masses adjacent to the osteo-destructions. CONCLUSIONS: The imaging manifestations of MFH were specific to some extent. Combined utilization of plain X-ray, CT, and MRI is helpful for the diagnosis and differential diagnosis of MFH.