Metastatic Neuroblastoma Presenting as a Submandibular Mass with Mandibular Bone Involvement in a Three-Year-Old Child.

Although neuroblastoma is one of the most common extra-cranial tumors in the pediatric population, it is rarely seen as a metastasis to the mandibular bone. The following is a case report of a 3-year-old male who initially presented with a submandibular mass that was proven to be a poorly differentiated metastatic neuroblastoma through excisional biopsy. This report is one of the few case reports that demonstrates metastatic submandibular neuroblastoma with mandibular bone involvement in the pediatric population.

Hypogastric Artery-Colonic Fistula after Coil Embolization of Left Hypogastric Artery Aneurysm.

Coil migration into the colon is an extremely rare complication of aneurysm embolization and only three cases have been reported. Two of these cases were managed with resection of the involved colon and the remaining case was managed with serial imaging. We present a 70-year-old man who developed hematochezia 2 years after coil embolization of a ruptured left hypogastric artery aneurysm. The patient was successfully treated with diverting colostomy and endoscopic closure of the sigmoid colon defect. We present the only case report of the use of advanced endoscopy to treat endovascular coil migration.

Cytomegalovirus pancreatitis in an immunocompetent patient.

Cytomegalovirus (CMV) is a double-stranded DNA virus, which infects a large portion of the adult population. In immunocompetent patients, it typically is asymptomatic or manifests as mild and self-limiting flu-like illness symptoms, whereas in immunocompromised patients, CMV can cause significant disease. Herein we report an unusual case of CMV pancreatitis in an immunocompetent 75-year-old female. Patient developed severe significant pancreatic necrosis that failed non-operative management, and ultimately underwent pancreatic necrosectomy. Later on, she developed three spontaneous gastric perforations. The first two perforations were managed operatively, but after the third perforation family decided not to undergo another operation. The CMV pancreatitis diagnosis was based on pancreatic histopathology and confirms by a prompt response to ganciclovir. Patient was promptly started on intravenous (IV) ganciclovir which resulted in clinical recovery and she remained asymptomatic more than one-year post op. This is a rare case of CMV pancreatitis with gastric perforations in an immunocompetent patient. High degree of suspicion and appropriate treatment are important for such clinical scenarios.

BTBD9 and dopaminergic dysfunction in the pathogenesis of restless legs syndrome.

Restless legs syndrome (RLS) is characterized by an urge to move legs, usually accompanied by uncomfortable sensations. RLS symptoms generally happen at night and can be relieved by movements. Genetic studies have linked polymorphisms in BTBD9 to a higher risk of RLS. Knockout of BTBD9 homolog in mice (Btbd9) and fly results in RLS-like phenotypes. A dysfunctional dopaminergic system is associated with RLS. However, the function of BTBD9 in the dopaminergic system and RLS is not clear. Here, we made use of the simple Caenorhabditis elegans nervous system. Loss of hpo-9, the worm homolog of BTBD9, resulted in hyperactive egg-laying behavior. Analysis of genetic interactions between hpo-9 and genes for dopamine receptors (dop-1, dop-3) indicated that hpo-9 and dop-1 worked similarly. Reporter assays of dop-1 and dop-3 revealed that hpo-9 knockout led to a significant increase of DOP-3 expression. This appears to be evolutionarily conserved in mice with an increased D2 receptor (D2R) mRNA in the striatum of the Btbd9 knockout mice. Furthermore, the striatal D2R protein was significantly decreased and Dynamin I was increased. Overall, activities of DA neurons in the substantia nigra were not altered, but the peripheral D1R pathway was potentiated in the Btbd9 knockout mice. Finally, we generated and characterized the dopamine neuron-specific Btbd9 knockout mice and detected an active-phase sleepiness, suggesting that dopamine neuron-specific loss of Btbd9 is sufficient to disturb the sleep. Our results suggest that increased activities in the D1R pathway, decreased activities in the D2R pathway, or both may contribute to RLS.

Probe the relationship between BTBD9 and MEIS1 in C. elegans and mouse.

Restless legs syndrome (RLS) is a neurological disorder characterized by an urge to move and uncomfortable sensations. Genetic studies have identified polymorphisms in up to 19 risk loci, including MEIS1 and BTBD9. Rodents deficient in either homolog show RLS-like phenotypes. However, whether MEIS1 and BTBD9 interact in vivo is unclear. Here, with C. elegans, we observed that the hyperactive egg-laying behavior caused by loss of BTBD9 homolog was counteracted by knockdown of MEIS1 homolog. This was further investigated in mutant mice with Btbd9, Meis1, or both knocked out. The double knockout mice showed an earlier onset of the motor deficit in the wheel running test but did not have increased sensitivity to the heat stimuli as observed in single KOs. Meis1 protein level was not influenced by Btbd9 deficiency, and Btbd9 transcription was not affected by Meis1 haploinsufficiency. Our results demonstrate that MEIS1 and BTBD9 do not regulate each other.

Gastric Mucormycosis in a Renal Transplant Patient Treated with Isavuconazole Monotherapy.

Gastrointestinal mucormycosis is a rare infection in solid organ transplant recipients. Our patient, a 79-year-old male, presented with severe dysphagia and odynophagia about 2 weeks after receiving a renal transplant. An upper gastrointestinal (UGI) endoscopy revealed esophagitis and gastric ulceration, the cultures from which grew Rhizopus species. A usual treatment strategy should include Amphotericin B as monotherapy or in combination with Posaconazole or Isavuconazole for such infections. Our patient was treated with Isavuconazole monotherapy, in an effort to minimize renal toxicity from Amphotericin B to the new allograft. Unique to our case was a successful clinical response and resolution of UGI lesions with Isavuconazole monotherapy. Due to the vagueness of presenting symptoms, such infections can be easily missed in an immunocompromised patient which can have tragic outcomes. Prompt diagnosis and modulation of immunosuppression are essential to decrease mortality and morbidity. Isavuconazole is a novel agent and can be used as a monotherapy for such infections, especially in renal transplant recipients.

Differential PI3Kδ Signaling in CD4+ T-cell Subsets Enables Selective Targeting of T Regulatory Cells to Enhance Cancer Immunotherapy.

To modulate T-cell function for cancer therapy, one challenge is to selectively attenuate regulatory but not conventional CD4+ T-cell subsets [regulatory T cell (Treg) and conventional T cell (Tconv)]. In this study, we show how a functional dichotomy in Class IA PI3K isoforms in these two subsets of CD4+ T cells can be exploited to target Treg while leaving Tconv intact. Studies employing isoform-specific PI3K inhibitors and a PI3Kδ-deficient mouse strain revealed that PI3Kα and PI3Kß were functionally redundant with PI3Kδ in Tconv. Conversely, PI3Kδ was functionally critical in Treg, acting there to control T-cell receptor signaling, cell proliferation, and survival. Notably, in a murine model of lung cancer, coadministration of a PI3Kδ-specific inhibitor with a tumor-specific vaccine decreased numbers of suppressive Treg and increased numbers of vaccine-induced CD8 T cells within the tumor microenvironment, eliciting potent antitumor efficacy. Overall, our results offer a mechanistic rationale to employ PI3Kδ inhibitors to selectively target Treg and improve cancer immunotherapy. Cancer Res; 77(8); 1892-904. ©2017 AACR.

Enhanced hippocampal long-term potentiation and fear memory in Btbd9 mutant mice.

Polymorphisms in BTBD9 have recently been associated with higher risk of restless legs syndrome (RLS), a neurological disorder characterized by uncomfortable sensations in the legs at rest that are relieved by movement. The BTBD9 protein contains a BTB/POZ domain and a BACK domain, but its function is unknown. To elucidate its function and potential role in the pathophysiology of RLS, we generated a line of mutant Btbd9 mice derived from a commercial gene-trap embryonic stem cell clone. Btbd9 is the mouse homolog of the human BTBD9. Proteins that contain a BTB/POZ domain have been reported to be associated with synaptic transmission and plasticity. We found that Btbd9 is naturally expressed in the hippocampus of our mutant mice, a region critical for learning and memory. As electrophysiological characteristics of CA3-CA1 synapses of the hippocampus are well characterized, we performed electrophysiological recordings in this region. The mutant mice showed normal input-output relationship, a significant impairment in pre-synaptic activity, and an enhanced long-term potentiation. We further performed an analysis of fear memory and found the mutant mice had an enhanced cued and contextual fear memory. To elucidate a possible molecular basis for these enhancements, we analyzed proteins that have been associated with synaptic plasticity. We found an elevated level of dynamin 1, an enzyme associated with endocytosis, in the mutant mice. These results suggest the first identified function of Btbd9 as being involved in regulating synaptic plasticity and memory. Recent studies have suggested that enhanced synaptic plasticity, analogous to what we have observed, in other regions of the brain could enhance sensory perception similar to what is seen in RLS patients. Further analyses of the mutant mice will help shine light on the function of BTBD9 and its role in RLS.

Abnormal nuclear envelope in the cerebellar Purkinje cells and impaired motor learning in DYT11 myoclonus-dystonia mouse models.

Myoclonus-dystonia (M-D) is a movement disorder characterized by myoclonic jerks with dystonia. DYT11 M-D is caused by mutations in SGCE which codes for ɛ-sarcoglycan. SGCE is maternally imprinted and paternally expressed. Abnormal nuclear envelope has been reported in mouse models of DYT1 generalized torsion dystonia. However, it is not known whether similar alterations occur in DYT11 M-D. We developed a mouse model of DYT11 M-D using paternally inherited Sgce heterozygous knockout (Sgce KO) mice and reported that they had myoclonus and motor coordination and learning deficits in the beam-walking test. However, the specific brain regions that contribute to these phenotypes have not been identified. Since ɛ-sarcoglycan is highly expressed in the cerebellar Purkinje cells, here we examined the nuclear envelope in these cells using a transmission electron microscope and found that they are abnormal in Sgce KO mice. Our results put DYT11 M-D in a growing family of nuclear envelopathies. To analyze the effect of loss of ɛ-sarcoglycan function in the cerebellar Purkinje cells, we produced paternally inherited cerebellar Purkinje cell-specific Sgce conditional knockout (Sgce pKO) mice. Sgce pKO mice showed motor learning deficits, while they did not show abnormal nuclear envelope in the cerebellar Purkinje cells, robust motor deficits, or myoclonus. The results suggest that ɛ-sarcoglycan in the cerebellar Purkinje cells contributes to the motor learning, while loss of ɛ-sarcoglycan in other brain regions may contribute to nuclear envelope abnormality, myoclonus and motor coordination deficits.