Evaluation of 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography in rat models with hepatocellular carcinoma with liver cirrhosis

Liver cirrhosis is a predominant risk factor for hepatocellular carcinoma (HCC). However, the exact mechanism of the progression from cirrhosis to cancer remains unclear. The uptake of 2-[(18)F]-fluoro-2-deoxy-D-glucose ((18)F-FDG) is widely used as a marker of increased glucose metabolism to monitor the progression of cancer with positron emission tomography (PET)/computed tomography (CT). Here we investigated the feasibility of using (18)F-FDG PET/CT in the diethylnitrosamine (DEN) mediated experimental hepatocellular carcinoma model. Rats received weekly intraperitoneal injections of DEN for 16 weeks for induction of HCC. We recorded starting from 0 days or 0 weeks after the last DEN injection. The weight and survival rate of rats were then measured. Also, an (18)F-FDG PET scan and serum analysis were performed at minus 2, 0, plus 2, and plus 4 weeks after the last DEN injection. The body weight of rats was maintained between 350 g and 370 g during 14 and 20 weeks, and the rats were euthanized at 35 days after the last DEN injection. The serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and alkaline phosphate (ALP) were significantly higher at zero weeks after the last DEN injection. The (18)F-FDG uptake for the quantitative evaluation of HCC was done by measuring the region of interest (ROI). At minus two weeks after the last DEN injection, the ROI of rats had significantly increased compared to the normal group, in a time-dependent manner. These results suggest that FDG uptake serves as a good screening test to evaluate the feasibility of DEN-induced HCC.

Role of TrkB in the anxiolytic-like and antidepressant-like effects of vagal nerve stimulation: Comparison with desipramine

A current hypothesis regarding the mechanism of antidepressant (AD) action suggests the involvement of brain-derived neurotrophic factor (BDNF). Consistent with this hypothesis, the receptor for BDNF (and neurotrophin 4/5 (NT-4/5)), Tropomyosin-related kinase B (TrkB), is activated in rodents by treatment with classical AD drugs. Vagal nerve stimulation (VNS), a therapy for treatment resistant depression (TRD), also activates TrkB in rodents. However, the role of this receptor in the therapeutic effects of VNS is unclear. In the current study, the involvement of TrkB in the effects of VNS was investigated in rats using its inhibitor, K252a. Anxiolytic-like and AD-like effects were analyzed using the novelty suppressed feeding test (NSFT) and forced swim test (FST), respectively. K252a blocked the anxiolytic-like effect of chronic VNS treatment and the AD-like effect of acute VNS treatment. By contrast, blocking TrkB did not prevent either the anxiolytic-like or AD-like effect of chronic treatment with desipramine (DMI), a selective noradrenergic reuptake inhibitor; it did, however, block the acute effect of DMI in the FST. To examine whether the activation of TrkB caused by either VNS or DMI is ligand-dependent, use was made of TrkB-Fc, a molecular scavenger for ligands of TrkB. Intraventricular administration of TrkB-Fc blocked the acute activation of TrkB induced by either treatment, indicating that treatment-induced activation of this receptor is ligand-dependent. The behavioral results highlight differences in the involvement of TrkB in the chronic effects of an AD drug and a stimulation therapy as well as its role in acute versus chronic effects of DMI.

Predisposition to and effects of methamphetamine use on the adolescent brain

Adolescence is a period of heightened vulnerability both to addictive behaviors and drug-induced brain damage. Yet, only limited information exists on the brain mechanisms underlying these adolescent-specific characteristics. Moreover, distinctions in brain correlates between predisposition to drug use and effects of drugs in adolescents are unclear. Using cortical thickness and diffusion tensor image analyses, we found greater and more widespread gray and white matter alterations, particularly affecting the frontostriatal system, in adolescent methamphetamine (MA) users compared with adult users. Among adolescent-specific gray matter alterations related to MA use, smaller cortical thickness in the orbitofrontal cortex was associated with family history of drug use. Our findings highlight that the adolescent brain, which undergoes active myelination and maturation, is more vulnerable to MA-related alterations than the adult brain. Furthermore, MA-use-related executive dysfunction was greater in adolescent MA users than in adult users. These findings may provide explanation for the severe behavioral complications and relapses that are common in adolescent-onset drug addiction. Additionally, these results may provide insights into distinguishing the neural mechanisms that underlie the predisposition to drug addiction from effects of drugs in adolescents.

A new reference line for the brain CT: the tuberculum sellae-occipital protuberance line is parallel to the anterior/posterior commissure line

BACKGROUND AND PURPOSE

CT and MR imaging of the brain have diverged reference lines. Modified Talairach anterior/posterior commissure (ACPC) line is widely accepted as the standard for clinical brain MR imaging, while orbitomeatal line (OML) is used for CT. This study sought to determine an appropriate reference line for brain CT parallel to the ACPC line.

MATERIALS AND METHODS

We measured the angles between the ACPC line and the OML, the line connecting the tuberculum sellae and the internal occipital protuberance (TS-IOP line), and the line connecting the tuberculum sellae and the external occipital protuberance (TS-EOP line) on midsagittal brain MR images of 223 patients. In addition, with the hard palate as the basis, the angles to the ACPC line in the brain MR images and new reference line on the brain CT images from the same patient were measured, and the difference between the 2 angles was calculated in 30 patients. In the same method, the angles to the OML in the brain CT images and the ACPC line on the brain MR images were measured, and their difference was calculated in 30 patients. Then the 2 difference values were compared with verification of the new reference line.

RESULTS

The angles between the ACPC line and both the TS-IOP line (0.0 degrees +/- 4.0 degrees ) and the TS-EOP line (0.8 degrees +/- 3.2 degrees ) were significantly smaller than the angles between the ACPC line and the OML (-12.6 degrees +/- 4.2 degrees ; P < .05). In actual scanned images, the angle differences between the TS-OP (TS-IOP + TS-EOP) line and the ACPC line (0.3 degrees +/- 4.5 degrees ) were statistically smaller than the angles between the OML and the ACPC line (-6.6 degrees +/- 3.9 degrees ; P < .05).

CONCLUSIONS

TS-OP lines are nearly parallel to the ACPC line.

AMG 479, a fully human anti-insulin-like growth factor receptor type I monoclonal antibody, inhibits the growth and survival of pancreatic carcinoma cells

Pancreatic carcinoma is a leading cause of cancer deaths, and recent clinical trials of a number of oncology therapeutics have not substantially improved clinical outcomes. We have evaluated the therapeutic potential of AMG 479, a fully human monoclonal antibody against insulin-like growth factor (IGF) type I receptor (IGF-IR), in two IGF-IR-expressing pancreatic carcinoma cell lines, BxPC-3 and MiaPaCa2, which also differentially express insulin receptor (INSR). AMG 479 bound to IGF-IR (K(D) 0.33 nmol/L) and blocked IGF-I and IGF-II binding (IC(50) < 0.6 nmol/L) without cross-reacting to INSR. AMG 479 completely inhibited ligand-induced (IGF-I, IGF-II, and insulin) activation of IGF-IR homodimers and IGF-IR/INSR hybrids (but not INSR homodimers) leading to reduced cellular viability in serum-deprived cultures. AMG 479 inhibited >80% of basal IGF-IR activity in BxPC-3 and MiaPaCa2 xenografts and prevented IGF-IR and IGF-IR/INSR hybrid activation following challenge with supraphysiologic concentrations of IGF-I. As a single agent, AMG 479 inhibited (∼ 80%) the growth of pancreatic carcinoma xenografts, and long-term treatment was associated with reduced IGF-IR signaling activity and expression. Efficacy seemed to be the result of two distinct biological effects: proapoptotic in BxPC-3 and antimitogenic in MiaPaCa2. The combination of AMG 479 with gemcitabine resulted in additive inhibitory activity both in vitro and in vivo. These results indicate that AMG 479 is a clinical candidate, both as a single agent and in combination with gemcitabine, for the treatment of patients with pancreatic carcinoma

Evidence of thalamic disinhibition in patients with hemichorea: semiquantitative analysis using SPECT

OBJECTIVES

Hemichorea sometimes occurs after lesions that selectively involve the caudate nucleus, putamen, and globus pallidus. Some reports have hypothesised that the loss of subthalamic nucleus control on the internal segment of the globus pallidus, followed by the disinhibition of the thalamus may contribute to chorea. However, the pathophysiology is poorly understood. Therefore, clinicoradiological localisation was evaluated and a comparison of the haemodynamic status of the basal ganglia and thalamus was made.

METHODS

Six patients presenting with acute onset of hemichorea were assessed. Neuroimaging studies, including MRI and SPECT examinations in addition to detailed biochemical tests, were performed. A semiquantitative analysis was performed by comparing the ratio of blood flow between patients and normal controls. In addition, the ratio of perfusion asymmetry was calculated as the ratio between each area contralateral to the chorea and that homolateral to the chorea. The comparison was made with a two sample t test.

RESULTS

The causes of hemichorea found consisted of four cases of acute stroke, one non-ketotic hyperglycaemia, and one systemic lupus erythematosus. Brain MRI indicated lesion sites in the contralateral putamen, globus pallidus, caudate nucleus, and subthalamic nucleus. A significant decrease in the ratio of blood flow in the basal ganglia contralateral to the chorea and a significant increase in the thalamus was found when comparing the perfusion asymmetries, which were calculated as the ratio of cerebral blood flow (CBF) for each region to that in the homolateral occipital area (p<0.05).

CONCLUSION

An alteration in CBF in both the contralateral thalamus and basal ganglia reflect the loss of pallidal inhibitory input from the pallidum to the thalamus. This change in CBF may be one of epiphenomena, which implicates an occurrence of hemichorea in humans.

Muscular sarcoidosis: Ga-67 scintigraphy and magnetic resonance imaging

Ga-67 scintigraphy is helpful in the assessment of active extrapulmonary sarcoidosis. Muscular involvement of sarcoidosis is often asymptomatic or nonspecific, and laboratory examinations do not provide convincing evidence of muscular involvement. The authors report a case of muscular sarcoidosis detected by Ga-67 scintigraphy. In a patient who had fever and arthralgia of both knee joints, Ga-67 scintigraphy showed mediastinal and hilar involvement of sarcoidosis with unexpected extensive muscular uptake. Magnetic resonance imaging revealed in detail intramuscular infiltration of sarcoid granuloma. Ga-67 scintigraphy is useful in detecting inflammatory muscular involvement of sarcoidosis and other multiorgan involvement.