Melanin, the pigment in hair, skin, eyes, and feathers, protects external tissue from damage by UV light. In contrast, neuromelanin (NM) is found in deep brain regions, specifically in loci that degenerate in Parkinson's disease. Although this distribution suggests a role for NM in Parkinson's disease neurodegeneration, the biosynthesis and function of NM have eluded characterization because of lack of an experimental system. We induced NM in rat substantia nigra and PC12 cell cultures by exposure to L-dihydroxyphenylalanine, which is rapidly converted to dopamine (DA) in the cytosol. This pigment was identical to human NM as assessed by paramagnetic resonance and was localized in double membrane autophagic vacuoles identical to NM granules of human substantia nigra. NM synthesis was abolished by adenoviral-mediated overexpression of the synaptic vesicle catecholamine transporter VMAT2, which decreases cytosolic DA by increasing vesicular accumulation of neurotransmitter. The NM is in a stable complex with ferric iron, and NM synthesis was inhibited by the iron chelator desferrioxamine, indicating that cytosolic DA and dihydroxyphenylalanine are oxidized by iron-mediated catalysis to membrane-impermeant quinones and semiquinones. NM synthesis thus results from excess cytosolic catecholamines not accumulated into synaptic vesicles. The permanent accumulation of excess catechols, quinones, and catechol adducts into a membrane-impermeant substance trapped in organelles may provide an antioxidant mechanism for catecholamine neurons. However, NM in organelles associated with secretory pathways may interfere with signaling, as it delays stimulated neurite outgrowth in PC12 cells. P arkinson's disease (PD) results from the death of neuromelanin (NM)-containing neurons in the substantia nigra pars compacta (SNC) (1) and the locus coeruleus (2). The presence of NM provides the characteristic pigmented appearance indicated by the names of these brain regions. NM appears in SNC DAergic neurons within 3 years of birth and increases with age (3). Because the neuronal populations that contain NM are those that die in PD, there has long been speculation that NM underlies PD pathogenesis. In one hypothesis, NM binds neurotoxins such as 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) (4) or paraquat (5), providing a pool of toxin within pigmented cells. Similarly, NM binds iron and toxic metals that could promote neurodegeneration (6, 7). Finally, NM could itself produce toxic free radicals (8). However, NM cannot be the sole causal factor in PD pathogenesis because all humans accumulate NM with age.Beyond the suggestions that NM underlies PD, there has been no suggestion of a biological function for this substance. Very little is known about NM biosynthesis, and it is not known where NM is synthesized in the cell, which intracellular or extracellular catecholamine pools are involved, or what triggers its formation (9-12). Although previous studies on NM synthesis have been performed on synthetic polymers arising from sponta...

BACKGROUND. Adoptive transfer of donor-derived EBV-specific cytotoxic T-lymphocytes (EBV-CTLs) can eradicate EBVassociated lymphomas (EBV-PTLD) after transplantation of hematopoietic cell (HCT) or solid organ (SOT) but is unavailable for most patients. METHODS.We developed a third-party, allogeneic, off-the-shelf bank of 330 GMP-grade EBV-CTL lines from specifically consented healthy HCT donors. We treated 46 recipients of HCT (n = 33) or SOT (n = 13) with established EBV-PTLD, who had failed rituximab therapy, with third-party EBV-CTLs. Treatment cycles consisted of 3 weekly infusions of EBV-CTLs and 3 weeks of observation. RESULTS.EBV-CTLs did not induce significant toxicities. One patient developed grade I skin graft-versus-host disease. Complete remission (CR) or sustained partial remission (PR) was achieved in 68% of HCT recipients and 54% of SOT recipients. For patients who achieved CR/PR or stable disease after cycle 1, one year overall survival was 88.9% and 81.8%, respectively. In addition, 3 of 5 recipients with POD after a first cycle who received EBV-CTLs from a different donor achieved CR or durable PR (60%) and survived longer than 1 year. Maximal responses were achieved after a median of 2 cycles. CONCLUSION.Third-party EBV-CTLs of defined HLA restriction provide safe, immediately accessible treatment for EBV-PTLD. Secondary treatment with EBV-CTLs restricted by a different HLA allele (switch therapy) can also induce remissions if initial EBV-CTLs are ineffective. These results suggest a promising potential therapy for patients with rituximab-refractory EBVassociated lymphoma after transplantation.Authorship note: SP and ED contributed equally to this work. Conflict of interest: ED and ROR had consultancy agreements with Atara Biotherapeutics. ED and ROR are inventors on technology referenced in this work (SK2013-71 [patient ID], Proprietary Cell Banks for Use in 3rd-Party EBV-Specific T Cell Therapy; and SK2018-122 [patient ID], Methods of Selecting T Cell Lines for Adoptive Cellular Therapy). SP is an inventor on technology referenced in this work (SK2013-71 and SK2018-122) and has waived rights to revenue generated from these inventions. Memorial Sloan Kettering Cancer Center (MSK), which owns the technology, has licensed this technology to Atara, and MSK has interests in Atara through this licensing arrangement.

The association between dietary obesity and mesolimbic systems that regulate hedonic aspects of feeding is currently unresolved. In the present study, we examined differences in baseline and stimulated central dopamine levels in obesity-prone (OP) and obesity-resistant (OR) rats. OP rats were hyperphagic and showed a 20% weight gain over OR rats at wk 15 of age, when fed a standard chow diet. This phenotype was associated with a 50% reduction in basal extracellular dopamine, as measured by a microdialysis probe in the nucleus accumbens, a projection site of the mesolimbic dopamine system that has been implicated in food reward. Similar defects were also observed in younger animals (4 wk old). In electrophysiology studies, electrically evoked dopamine release in slice preparations was significantly attenuated in OP rats, not only in the nucleus accumbens but also in additional terminal sites of dopamine neurons such as the accumbens shell, dorsal striatum, and medial prefrontal cortex, suggesting that there may be a widespread dysfunction in mechanisms regulating dopamine release in this obesity model. Moreover, dopamine impairment in OP rats was apparent at birth and associated with changes in expression of several factors regulating dopamine synthesis and release: vesicular monoamine transporter-2, tyrosine hydroxylase, dopamine transporter, and dopamine receptor-2 short-form. Taken together, these results suggest that an attenuated central dopamine system would reduce the hedonic response associated with feeding and induce compensatory hyperphagia, leading to obesity.

Huntington's disease (HD) is caused by an expanded CAG repeat in exon 1 of the gene coding for the huntingtin protein. The cellular pathway by which this mutation induces HD remains unknown, although alterations in protein degradation are involved. To study intrinsic cellular mechanisms linked to the mutation, we examined dissociated postnatally derived cultures of striatal neurons from transgenic mice expressing exon 1 of the human HD gene carrying a CAG repeat expansion. While there was no difference in cell death between wild-type and mutant littermate-derived cultures, the mutant striatal neurons exhibited elevated cell death following a single exposure to a neurotoxic concentration of dopamine. The mutant neurons exposed to dopamine also exhibited lysosome-associated responses including induction of autophagic granules and electron-dense lysosomes. The autophagic/lysosomal compartments co-localized with high levels of oxygen radicals in living neurons, and ubiquitin. The results suggest that the combination of mutant huntingtin and a source of oxyradical stress (provided in this case by dopamine) induces autophagy and may underlie the selective cell death characteristic of HD.

WHAT'S KNOWN ON THIS SUBJECT: Previous studies have confirmed feasibility of MRI for diagnosis of appendicitis in adults and children. No study has assessed clinical end points when using ultrasound and MRI compared with computed tomography for diagnosis of appendicitis in children.WHAT THIS STUDY ADDS: Radiation-free imaging with ultrasound selectively followed by MRI does not change clinical endpoints compared with CT for diagnosing appendicitis in children, with no difference in time to antibiotic administration, time to appendectomy, negative appendectomy rate, perforation rate, or length of stay. abstract BACKGROUND: Cross-sectional imaging increases accuracy in diagnosing appendicitis. We hypothesized that a radiation-free imaging pathway of ultrasonography selectively followed by MRI would not change clinical end points compared with computed tomography (CT) for diagnosis of acute appendicitis in children. METHODS:We retrospectively reviewed children (,18 years old) who had diagnostic imaging for suspected acute appendicitis between November 2008 and October 2012. Before November 2010 CT was used as the primary imaging modality (group A); subsequently, ultrasonography was the primary imaging modality followed by MRI for equivocal findings (group B). Data collected included time from triage to imaging and treatment and results of imaging and pathology.RESULTS: Six hundred sixty-two patients had imaging for suspected appendicitis (group A = 265; group B = 397, of which 136 [51%] and 161 [41%], respectively, had positive imaging for appendicitis). Negative appendectomy rate was 2.5% for group A and 1.4% for group B. Perforation rate was similar for both groups. Time from triage to antibiotic administration and operation did not differ between groups A and B. There was higher proportion of positive imaging and appendectomies in group A and thus more negative imaging tests in group B (ultrasonography and MRI), but diagnostic accuracy of the 2 imaging pathways was similar. CONCLUSIONS:In children with suspected acute appendicitis, a radiationfree diagnostic imaging of ultrasonography selectively followed by MRI is feasible and comparable to CT, with no difference in time to antibiotic administration, time to appendectomy, negative appendectomy rate, perforation rate, or length of stay.