Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Imitators of chronic pancreatitis: diffuse neuroendocrine tumour of the pancreas.

We report a rare case of diffuse replacement of the pancreas with neuroendocrine tumour mimicking chronic pancreatitis. A 55-year-old female with no significant past medical history initially presented with abdominal pain in 2006. A CT of the abdomen and pelvis was performed, revealing diffuse pancreatic parenchymal calcifications with mild pancreatic ductal dilatation and no discrete mass. She was diagnosed with chronic pancreatitis and followed clinically until 2015, where she presented with recurrent abdominal pain. A repeat CT and MRI of the abdomen were performed which revealed new hypoenhancing masses within the pancreas, particularly in the pancreatic tail. There was a persistent background of pancreatic parenchymal calcifications. The possibility of pancreatic neuroendocrine tumour was raised, and an indium-111 Octreotide scan was recommended. Diffuse intense uptake was identified throughout the pancreas on the indium-111 imaging. Given the concern for neuroendocrine tumour, a total pancreatectomy was performed, with histopathology revealing replacement of the pancreas with coalescing well-circumscribed nodules. Many of the nodules had numerous calcifications and localized amyloid deposition. Immunohistochemical stains of the neoplastic cells were strong for neuroendocrine markers chromogranin A and synaptophysin. Overall the findings were consistent with numerous neuroendocrine tumours of the pancreas, Grade II, as per the 2010 WHO criteria for neuroendocrine tumours of the pancreas. Neuroendocrine tumours of the pancreas are lesions that arise from the islet cells, with an approximate incidence of five cases per million people per year. Only one other case report has been documented in the literature by Singh et al demonstrating diffuse pancreatic neuroendocrine tumour replacing the entire pancreas. As diffuse pancreatic neuroendocrine tumour can look similar on imaging to chronic pancreatitis or other infiltrative processes, we wanted to present this case and some of the more specific imaging findings in distinguishing these entities

Two Cases of Crystal-storing Histiocytosis Diagnosed by Morphology, Immunohistochemistry, and Ultrastructural Examination.

Crystal-storing histiocytosis (CSH) is a non-neoplastic histiocytic proliferation containing crystalline material, usually associated with an underlying lymphoproliferative or plasmacytic disorder. The crystalline structures are typically derived from kappa light chain immunoglobulins. The lesions of CSH are comprised of sheets of histiocytes with abundant eosinophilic cytoplasm containing variably prominent, elongated crystals. This rare phenomenon is important to recognize, as it is known to morphologically obscure an underlying neoplasm. Histologically, the cells of CSH may closely mimic Gaucher cells, as well as the pseudo-Gaucher cells sometimes encountered in chronic myeloid leukemia. The distinction between the cells of CSH and that of histologic mimics may be made more definitively through the use of electron microscopy, as the crystalline inclusions seen in CSH display characteristic size, shape, and localization within the cells. Here, we report 2 rare cases of CSH diagnosed by morphology, immunohistochemistry, and ultrastructural examination. The first case presented was diagnosed concurrently with plasma cell myeloma, and the second case discussed was diagnosed in association with marginal zone lymphoma

Innate immune responses and permissiveness to ranavirus infection of peritoneal leukocytes in the frog Xenopus laevis.

Ranaviruses such as frog virus 3 ([FV3] family Iridoviridae) are increasingly prevalent pathogens that infect reptiles, amphibians, and fish worldwide. Whereas studies in the frog Xenopus laevis have revealed the critical involvement of CD8 T-cell and antibody responses in host resistance to FV3, little is known about the role played by innate immunity to infection with this virus. We have investigated the occurrence, composition, activation status, and permissiveness to infection of peritoneal leukocytes (PLs) in Xenopus adults during FV3 infection by microscopy, flow cytometry, and reverse transcription-PCR. The total number of PLs and the relative fraction of activated mononucleated macrophage-like cells significantly increase as early as 1 day postinfection (dpi), followed by NK cells at 3 dpi, before the peak of the T-cell response at 6 dpi. FV3 infection also induces a rapid upregulation of proinflammatory genes including arginase 1, interleukin-1beta, and tumor necrosis factor alpha. Although PLs are susceptible to FV3 infection, as evidenced by apoptotic cells, active FV3 transcription, and the detection of viral particles by electron microscopy, the infection is weaker (fewer infectious particles), more transitory, and involves a smaller fraction (less than 1%) of PLs than the kidney, the main site of infection. However, viral DNA remains detectable in PLs for at least 3 weeks postinfection, past the point of viral clearance observed in the kidneys. This suggests that although PLs are actively involved in anti-FV3 immune responses, some of these cells can be permissive and harbor quiescent, asymptomatic FV3

Non-linearity within the primary measurement range of a lipase assay as the cause of a gap in the interpatient lipase results distribution.

OBJECTIVES: Interpatient distribution data for lipase (Roche Cobas® assay) showed an unexpected data gap, where no results were reported. This gap occurred beginning at a point just above the assay\u27s primary measurement range (i.e., above the cutoff (300U/L) for automated repeat-on-dilution). Calculation or other errors within the automated dilution process were ruled out. Linearity of assay results was investigated. DESIGN AND METHODS: Linearity of experimental sample dilution series data was assessed by correlation coefficient, intercept, and constancy of slope. RESULTS: Dilution experiment data demonstrated a discontinuity of results between 300 and 400U/L consistent with the observed gap in patient data. Although data within the presumed linear range of the assay had a high linear correlation coefficient (r2\u3e0.99), a non-zero intercept and progressively variable slope were inconsistent with linearity. Although the assay was assessed as linear by the College of American Pathology linearity survey, survey data also demonstrated non-linearity for this assay when analyzed for slopes and intercept. CONCLUSIONS: Non-linearity in the presumed linear range of an assay can produce gaps in patient data above a repeat-on-dilution cutoff. As in this instance, CAP linearity surveys may not identify certain forms of non-linearity

Cholesterol granulomas presenting as sellar masses: a similar, but clinically distinct entity from craniopharyngioma and Rathke\u27s cleft cyst.

PURPOSE: Cholesterol granulomas in the sella are rare and can mimic the appearance of craniopharyngioma or Rathke\u27s cleft cysts. Information regarding the clinical presentation, imaging characteristics, and clinical course of sellar cholesterol granulomas can help clinicians to differentiate these lesions from other sellar cystic lesions. METHODS: We present three cases of sellar cholesterol granulomas. A literature review was performed for all cases of sellar cholesterol granulomas with individual patient data reported. RESULTS: We identified 24 previously reported cases in addition to our three cases. Mean age was 36.6 years (range 5-68). There were 16 (59%) females. The most common (74%) presenting symptom was endocrinological deficits, typically either isolated diabetes insipidus (DI) or panhypopituitarism. Location was intrasellar in 3 (11%), suprasellar in 6 (22%), and intrasellar/suprasellar in 18 (67%) patients. Lesions were most commonly (83%) T1 hyperintense. Gross total resection was achieved in 16 (64%) and subtotal resection in 9 (36%) patients. Of the seventeen (63%) patients presenting with varying degrees of bitemporal hemianopsia, all had improvement in vision postoperatively. It is worth noting that no cases of preoperative hypopituitarism or DI improved postoperatively. Even though gross total resection was only achieved in 64%, there was only one recurrence reported. CONCLUSION: Sellar cholesterol granulomas are characterized by T1 hyperintensity, younger age, and more frequent and severe endocrinological deficits on presentation. Our review demonstrates high rates of improvement of visual deficits, but poor rates of endocrine function recovery. Recurrence is uncommon even in cases of subtotal resection