A B S T R A C T PurposeChildren with relapsed neuroblastoma have poor survival. It is crucial to have a reliable method for evaluating functional response to new therapies. In this study, we compared two functional imaging modalities for neuroblastoma: metaiodobenzylguanidine (MIBG) scan for uptake by the norepinephrine transporter and [18 F]fluorodeoxyglucose positron emission tomography (FDG-PET) uptake for glucose metabolic activity. Patients and MethodsPatients enrolled onto a phase I study of sequential infusion of iodine-131 ( 131 I) MIBG (NANT-2000-01) were eligible for inclusion if they had concomitant FDG-PET and MIBG scans.131 I-MIBG therapy was administered on days 0 and 14. For each patient, we compared all lesions identified on concomitant FDG-PET and MIBG scans and gave scans a semiquantitative score. ResultsThe overall concordance of positive lesions on concomitant MIBG and FDG-PET scans was 39.6% when examining the 139 unique anatomic lesions. MIBG imaging was significantly more sensitive than FDG-PET overall and for the detection of bone lesions (P Ͻ .001). There was a trend for increased sensitivity of FDG-PET for detection of soft tissue lesions. Both modalities showed similar improvement in number of lesions identified from day 0 to day 56 scan and in semiquantitative scores that correlated with overall response. FDG-PET scans became completely negative more often than MIBG scans after treatment. ConclusionMIBG scan is significantly more sensitive for individual lesion detection in relapsed neuroblastoma than FDG-PET, though FDG-PET can sometimes play a complementary role, particularly in soft tissue lesions. Complete response by FDG-PET metabolic evaluation did not always correlate with complete response by MIBG uptake.

Astrocytes, an abundant form of glia, are known to promote and modulate synaptic signaling between neurons. They also express α7-containing nicotinic acetylcholine receptors (α7-nAChRs), but the functional relevance of these receptors is unknown. We show here that stimulation of α7-nAChRs on astrocytes releases components that induce hippocampal neurons to acquire more a-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors post-synaptically at glutamatergic synapses. The increase is specific in that no change is seen in synaptic NMDA receptor clusters or other markers for glutamatergic synapses, or in markers for GABAergic synapses. Moreover, the increases in AMPA receptors on the neuron surface are accompanied by increases in the frequency of spontaneous miniature synaptic currents mediated by the receptors and increases in the ratio of evoked synaptic currents mediated by AMPA versus NMDA receptors. This suggests that stimulating α7-nAChRs on astrocytes can convert ‘silent’ glutamatergic synapses to functional status. Astrocyte-derived thrombospondin is necessary but not sufficient for the effect, while tumor necrosis factor-α is sufficient but not necessary. The results identify astrocyte α7-nAChRs as a novel pathway through which nicotinic cholinergic signaling can promote the development of glutamatergic networks, recruiting AMPA receptors to post-synaptic sites and rendering the synapses more functional.

SummaryType 1 hepatorenal syndrome (HRS) is characterized by rapid deterioration of renal function. We sought to assess native kidney function after combined kidney-liver transplant (CLKTx) performed for type 1 HRS. We performed a retrospective, cross-sectional, single-center study. All patients with Type 1 HRS who received a CLKTx at the University of California, San Francisco from 1997 to 2007 were screened for enrollment. Patients with a baseline estimated glomerular filtration rate (eGFR) ! 30 ml/min/1.73 m 2 were eligible. Twenty-three patients were identified and consented to receive a Technetium-99 m-mercaptoacetyltriglycine (MAG3) nuclear scan to measure the native kidney contribution to overall renal function. Only 4 of the 23 subjects (17.4%) demonstrated native renal function that consisted of a contribution ! 50% of total renal function. Several factors and comorbidities such as age, gender, race, duration of HRS, need for and duration of renal replacement therapy, need for pressors, urine sodium, proteinuria, and use of octreotide/midodrine were analyzed and not found to be significant in predicting native renal function. The assessment of post-transplant native renal function following CLKTx may allow for improved accuracy in identifying the patients in need of CLKTx, and thus allow for greater optimization of dual-organ allocation strategies in patients with concomitant liver and renal failure.

No abstract

A biopsy-proven fat-containing metastasis to the adrenal gland in a patient with hepatocellular carcinoma demonstrated low density on nonenhanced CT, heterogeneity on contrast-enhanced CT, and marked signal loss on opposed-phase gradient-echo MRI, mimicking an adrenal adenoma. However, the mass was not present on older studies and showed increased FDG uptake on PET. The possibility of a fat-containing metastasis should be considered for an apparent adrenal adenoma in a patient with a primary hepatocellular carcinoma.