Restoration of amyloid PET images obtained with short-time data using a generative adversarial networks framework.

Our purpose in this study is to evaluate the clinical feasibility of deep-learning techniques for F-18 florbetaben (FBB) positron emission tomography (PET) image reconstruction using data acquired in a short time. We reconstructed raw FBB PET data of 294 patients acquired for 20 and 2 min into standard-time scanning PET (PET20m) and short-time scanning PET (PET2m) images. We generated a standard-time scanning PET-like image (sPET20m) from a PET2m image using a deep-learning network. We did qualitative and quantitative analyses to assess whether the sPET20m images were available for clinical applications. In our internal validation, sPET20m images showed substantial improvement on all quality metrics compared with the PET2m images. There was a small mean difference between the standardized uptake value ratios of sPET20m and PET20m images. A Turing test showed that the physician could not distinguish well between generated PET images and real PET images. Three nuclear medicine physicians could interpret the generated PET image and showed high accuracy and agreement. We obtained similar quantitative results by means of temporal and external validations. We can generate interpretable PET images from low-quality PET images because of the short scanning time using deep-learning techniques. Although more clinical validation is needed, we confirmed the possibility that short-scanning protocols with a deep-learning technique can be used for clinical applications.

Osteosarcoma of talus with heterotopic ossifications and lung metastases.

Osteosarcoma is the most common malignant bone tumor and is known to occur mainly in the metaphyses of long bones. However, a few cases of osteosarcoma in talus have been reported in older patients. We experienced an osteosarcoma of an 80-year-old male patient with a talus which is rarely reported and evaluated disease patterns with four different imaging modalities.

Central peptidergic ensembles associated with organization of an innate behavior.

At the end of each developmental stage, insects perform the ecdysis sequence, an innate behavior necessary for shedding the old cuticle. Ecdysis triggering hormones (ETHs) initiate these behaviors through direct actions on the CNS. Here, we identify the ETH receptor (ETHR) gene in the moth Manduca sexta, which encodes two subtypes of GPCR (ETHR-A and ETHR-B). Expression of ETHRs in the CNS coincides precisely with acquisition of CNS sensitivity to ETHs and behavioral competence. ETHR-A occurs in diverse networks of neurons, producing both excitatory and inhibitory neuropeptides, which appear to be downstream signals for behavior regulation. These peptides include allatostatins, crustacean cardioactive peptide (CCAP), calcitonin-like diuretic hormone, CRF-like diuretic hormones (DHs) 41 and 30, eclosion hormone, kinins, myoinhibitory peptides (MIPs), neuropeptide F, and short neuropeptide F. In particular, cells L(3,4) in abdominal ganglia coexpress kinins, DH41, and DH30, which together elicit the fictive preecdysis rhythm. Neurons IN704 in abdominal ganglia coexpress CCAP and MIPs, whose joint actions initiate the ecdysis motor program. ETHR-A also is expressed in brain ventromedial cells, whose release of EH increases excitability in CCAP/MIP neurons. These findings provide insights into how innate, centrally patterned behaviors can be orchestrated via recruitment of peptide cotransmitter neurons.

Corazonin receptor signaling in ecdysis initiation.

Corazonin is a highly conserved neuropeptide hormone of wide-spread occurrence in insects yet is associated with no universally recognized function. After discovery of the corazonin receptor in Drosophila, we identified its ortholog in the moth, Manduca sexta, as a prelude to physiological studies. The corazonin receptor cDNA in M. sexta encodes a protein of 436 amino acids with seven putative transmembrane domains and shares common ancestry with its Drosophila counterpart. The receptor exhibits high sensitivity and selectivity for corazonin when expressed in Xenopus oocytes (EC(50) approximately 200 pM) or Chinese hamster ovary cells (EC(50) approximately 75 pM). Northern blot analysis locates the receptor in peripheral endocrine Inka cells, the source of preecdysis- and ecdysis-triggering hormones. Injection of corazonin into pharate larvae elicits release of these peptides from Inka cells, which induce precocious preecdysis and ecdysis behaviors. In vitro exposure of isolated Inka cells to corazonin (25-100 pM) induces preecdysis- and ecdysis-triggering hormone secretion. Using corazonin receptor as a biosensor, we show that corazonin concentrations in the hemolymph 20 min before natural preecdysis onset range from 20 to 80 pM and then decline over the next 30-40 min. These findings support the role of corazonin signaling in initiation of the ecdysis behavioral sequence. We propose a model for peptide-mediated interactions between Inka cells and the CNS underlying this process in insect development.