Rapid spectral variability of a giant flare from a magnetar in NGC 253.

Magnetars are neutron stars with extremely strong magnetic fields (1013 to 1015 gauss)1,2, which episodically emit X-ray bursts approximately 100 milliseconds long and with energies of 1040 to 1041 erg. Occasionally, they also produce extremely bright and energetic giant flares, which begin with a short (roughly 0.2 seconds), intense flash, followed by fainter, longer-lasting emission that is modulated by the spin period of the magnetar3,4 (typically 2 to 12 seconds). Over the past 40 years, only three such flares have been observed in our local group of galaxies3-6, and in all cases the extreme intensity of the flares caused the detectors to saturate. It has been proposed that extragalactic giant flares are probably a subset7-11 of short γ-ray bursts, given that the sensitivity of current instrumentation prevents us from detecting the pulsating tail, whereas the initial bright flash is readily observable out to distances of around 10 to 20 million parsecs. Here we report X-ray and γ-ray observations of the γ-ray burst GRB 200415A, which has a rapid onset, very fast time variability, flat spectra and substantial sub-millisecond spectral evolution. These attributes match well with those expected for a giant flare from an extragalactic magnetar12, given that GRB 200415A is directionally associated13 with the galaxy NGC 253 (roughly 3.5 million parsecs away). The detection of three-megaelectronvolt photons provides evidence for the relativistic motion of the emitting plasma. Radiation from such rapidly moving gas around a rotating magnetar may have generated the rapid spectral evolution that we observe.

Observation of inverse Compton emission from a long γ-ray burst.

Long-duration γ-ray bursts (GRBs) originate from ultra-relativistic jets launched from the collapsing cores of dying massive stars. They are characterized by an initial phase of bright and highly variable radiation in the kiloelectronvolt-to-megaelectronvolt band, which is probably produced within the jet and lasts from milliseconds to minutes, known as the prompt emission1,2. Subsequently, the interaction of the jet with the surrounding medium generates shock waves that are responsible for the afterglow emission, which lasts from days to months and occurs over a broad energy range from the radio to the gigaelectronvolt bands1-6. The afterglow emission is generally well explained as synchrotron radiation emitted by electrons accelerated by the external shock7-9. Recently, intense long-lasting emission between 0.2 and 1 teraelectronvolts was observed from GRB 190114C10,11. Here we report multi-frequency observations of GRB 190114C, and study the evolution in time of the GRB emission across 17 orders of magnitude in energy, from 5 × 10-6 to 1012 electronvolts. We find that the broadband spectral energy distribution is double-peaked, with the teraelectronvolt emission constituting a distinct spectral component with power comparable to the synchrotron component. This component is associated with the afterglow and is satisfactorily explained by inverse Compton up-scattering of synchrotron photons by high-energy electrons. We find that the conditions required to account for the observed teraelectronvolt component are typical for GRBs, supporting the possibility that inverse Compton emission is commonly produced in GRBs.

Preoperative and postoperative nasal septal surgery assessment with acoustic rhinometry.

INTRODUCTION: Acoustic rhinometry is a relatively new tool used for the measurement of the geometry of the nasal fossa. We hypothesized that acoustic rhinometry would be useful for preoperative and postoperative assessment of patients undergoing septal surgery. METHODS AND MATERIAL: Twenty-four patients undergoing septal surgery performed by two surgeons underwent preoperative and postoperative rhinometry. The indications for surgery were nasal obstruction caused by a deviated nasal septum. Rhinometry was conducted with the Eccovision Acoustic Rhinometry System (Hood Laboratories). Analysis of the data was performed with the Kwikstat program (Texasoft) and Excel (Microsoft). RESULTS: Subjective improvement in nasal patency was significantly correlated with improvement in acoustic rhinometry. CONCLUSIONS: Acoustic rhinometry is valuable in objectively confirming nasal patency after nasal septal and turbinate surgery.

Public policy solutions sought for emergency care.

Public policy plays an increasing role in emergency cardiac care. Barriers to increasing the survival rates for sudden cardiac arrest have been laid down by legislators and regulators at the state and federal levels. Legislative activities must complement scientific advances to achieve a fully functioning chain of survival.

Use of a rapid assay of subforms of creatine kinase MB to diagnose or rule out acute myocardial infarction.

BACKGROUND: Ruling out myocardial infarction in patients coming to the emergency room with chest pain is hindered by the lack of a specific early diagnostic marker. Less than 30 percent of patients admitted to coronary care units have infarction, resulting in substantial unnecessary expenditures. We developed a rapid assay of the subforms of creatine kinase MB (CK-MB) and prospectively analyzed its sensitivity and specificity in diagnosing myocardial infarction in the first six hours after the onset of chest pain. METHODS: In 1110 consecutive patients who came to the emergency room with chest pain, blood samples were collected every 30 to 60 minutes until at least 6 hours after the onset of symptoms; in patients who were then admitted to the hospital, samples were collected every 4 hours for up to 48 hours. The samples were analyzed for CK-MB subforms, and the diagnosis of myocardial infarction was confirmed by conventional CK-MB analysis. RESULTS: Of the 1110 patients evaluated, 121 had myocardial infarction. The sensitivity of the assay of CK-MB subforms to detect myocardial infarction in the first six hours after the onset of symptoms was 95.7 per cent, as compared with only 48 percent for the conventional CK-MB assay; the specificity was 93.9 percent among patients hospitalized without myocardial infarction and 96.2 percent among those sent home. Among the patients with myocardial infarction, definitive results of the subform assay were available a mean (+/- SD) of 1.22 +/- 1.17 hours after their arrival in the emergency room. CONCLUSIONS: The assay of CK-MB subforms reliably detected myocardial infarction within the first six hours after the onset of symptoms, and its use could reduce admission to the coronary care unit by 50 to 70 percent, thereby reducing costs.

Metabolic and diagnostic significance of creatine kinase isoenzymes.

Creatine kinase isoenzyme content is frequently used to assess the state of differentiation of muscle and neural tissue and following release into plasma as diagnostic markers for acute myocardial infarction, skeletal muscle disease, and neurologic injury. The establishment of thrombolytic therapy as the standard of care for acute myocardial infarction and new information on the tissue distribution of creatine kinase isoenzymes has necessitated the development of more rapid assays for the diagnosis of infarction and expanded the potential use of these isoenzymes as markers for other disease states.

Muscle creatine kinase isoenzyme expression in adult human brain.

Previous studies have suggested that MM creatine kinase is a muscle-specific protein and is not present in adult brain tissue. We have isolated a protein from human brain with an apparent molecular weight of 43,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis which is identical to the muscle M creatine kinase isoenzyme subunit at all 30 sequenced amino acid residues and possesses creatine kinase enzymatic activity following nondenaturing agarose-gel electrophoresis. Immunohistochemistry localizes M creatine kinase to discrete areas of adult human brain. Northern blot analysis of both total and poly(A)-selected RNA isolated from brain did not detect M creatine kinase mRNA. However, polymerase chain reaction amplification of cDNA synthesized from human placenta, heart, and brain mRNA detected M creatine kinase message in both heart and brain but not placenta which contains no detectable M creatine kinase protein. N1E115 and NS20Y, mouse neuroblastoma cell lines which have been used as models of neural cell differentiation, were found also to express MM creatine kinase. Moreover, a transiently transfected reporter gene with 4,800 base pairs of M creatine kinase upstream region fused to chloramphenicol acetyltransferase was expressed during differentiation of these neural cell lines. In summary, MM creatine kinase is present in human brain and we suggest the M creatine kinase upstream region is sufficient to modulate M creatine kinase expression in certain neuronal cells and may be regulated independently from other muscle genes.

Microvascular revascularization of the tongue.

Revascularization of the tongue, employing microvascular techniques, is useful in cases where the blood supply to this organ must be interrupted to allow for adequate exposure or for adequate margins. A case is presented in which the left lingual artery was divided for purposes of exposure and the right artery was interrupted to encompass the entire tumor. This patient also underwent a total laryngopharyngectomy with jejunal free flap interposition. The blood supply of the tongue was successfully reestablished by anastomosing the right lingual artery to the right facial artery. The patient made an uneventful recovery.

Phenotypic modulation of the swarm rat chondrosarcoma induced by morphogenetic bone matrix.

The recognized similarities between developing embryonic tissues and neoplastic cells have led to a number of experimental demonstrations which indicate that inductive microenvironments can alter the malignant phenotype. In postnatal life a morphogenetic cascade resembling endochondral bone development can be induced by s.c. implantation of demineralized diaphyseal bone matrix. We have examined the ability of this microenvironment to alter the phenotype of the transplantable Swarm rat chondrosarcoma in mixed implants. Neoplastic chondrocytes could be distinguished from host cells by nuclear morphometry since the nuclear area of the neoplastic chondrocytes was 2 to 3 times larger than that of comparable host-derived chondrocytes. Through the first 7 days post-implantation tumor cells in the presence of morphogenetically active matrix are morphologically indistinguishable from those implanted with morphogenetically inactivated matrix or implanted by themselves. With the advent of host cell chondrogenesis, however, adjacent neoplastic cells begin to undergo chondrolysis and calcification. Only those cells in the immediate proximity of host morphogenetic foci appear affected. An average of 26.7 +/- 7.0% (SD) of the implant surface areas examined revealed such changes. Chondrosarcoma cells implanted by themselves or in the presence of morphogenetically inactivated bone matrix underwent no such changes. These results suggest that factors released from host cells induced to undergo bone morphogenesis are capable of altering the differentiated phenotype of neoplastic cells.