A hybrid type Ia supernova with an early flash triggered by helium-shell detonation.

Type Ia supernovae arise from the thermonuclear explosion of white-dwarf stars that have cores of carbon and oxygen. The uniformity of their light curves makes these supernovae powerful cosmological distance indicators, but there have long been debates about exactly how their explosion is triggered and what kind of companion stars are involved. For example, the recent detection of the early ultraviolet pulse of a peculiar, subluminous type Ia supernova has been claimed as evidence for an interaction between a red-giant or a main-sequence companion and ejecta from a white-dwarf explosion. Here we report observations of a prominent but red optical flash that appears about half a day after the explosion of a type Ia supernova. This supernova shows hybrid features of different supernova subclasses, namely a light curve that is typical of normal-brightness supernovae, but with strong titanium absorption, which is commonly seen in the spectra of subluminous ones. We argue that this early flash does not occur through previously suggested mechanisms such as the companion-ejecta interaction. Instead, our simulations show that it could occur through detonation of a thin helium shell either on a near-Chandrasekhar-mass white dwarf, or on a sub-Chandrasekhar-mass white dwarf merging with a less-massive white dwarf. Our finding provides evidence that one branch of previously proposed explosion models-the helium-ignition branch-does exist in nature, and that such a model may account for the explosions of white dwarfs in a mass range wider than previously supposed.

Serum trace elements in tube-fed neurological dysphagia patients correlate with nutritional indices but do not correlate with trace element intakes: case of patients receiving enough trace elements intake.

BACKGROUND & AIMS: Patients who have neurological dysphagia induced by cerebrovascular disease are at high risk of malnutrition and aspiration pneumonia. Since trace elements in serum bind to serum protein, serum trace elements concentration is influenced by serum protein concentration. In addition, serum protein concentration is influenced by malnutrition and inflammation. Therefore, evaluation of serum trace elements concentration has to consider influence of malnutrition and inflammation. In recent years, enteral formula including rich trace elements were developed to prevent trace elements deficiency. However, serum trace elements concentration showed a low level even if patients were receiving enough trace elements intake. We thought that it was effective in nutritional management of patients with malnutrition and inflammation to clarify about correlation among nutritional indices, serum trace elements, and the amount of trace element intake in tube-fed patients. In this study, we aimed to determine nutritional indices that are predictors of serum trace elements in patients with neurological dysphagia on long-term tube feeding. METHODS: Subjects were 40 elderly bedridden patients with neurological dysphagia induced by cerebrovascular disease. All subjects were fed total enteral nutrition via nasogastric tube. We investigated serum trace elements (iron, copper, zinc) and nutritional indices (body mass index, albumin, transferrin, ceruloplasmin, C-reactive protein, hemoglobin, lymphocyte, trace elements intake), and analyzed by multiple regression analysis. In addition, we divided subjects into two groups based on inflammatory response. The first group was 20 patients with inflammation (inflammation group), and another group was 20 patients without pneumonia (control group). RESULTS: Subjects were malnourished and showed inflammatory response: low body weight (55%), hypoalbuminemia (58%), moderate or severe inflammation (53%), anemia (38%). Ratio of low serum iron concentration was 43%. Ratio of high serum copper concentration was 45%. Ratio of low serum zinc concentration was 65%. Mean of trace elements intake was slightly more than requirements. In multiple regression analysis in all subjects, predictor of serum iron was hemoglobin (P<0.01) and transferrin (P<0.05), predictor of serum copper was ceruloplasmin (P<0.001) and C-reactive protein (P<0.05), predictor of serum zinc was albumin (P<0.05). In comparisons of nutritional status between inflammation group and control group, serum zinc concentration in inflammation group was significantly lower than control group. On the other hand, ceruloplasmin, C-reactive protein and serum copper concentration in inflammation group were significantly higher than control group. There was no significant difference in daily trace elements intake between inflammation group and control group. CONCLUSION: In tube-fed patients with neurological dysphagia, serum trace elements concentration was influenced by malnutrition and inflammation. It was suggested that serum trace elements concentration might not be normalized if malnutrition and inflammation are not treated. We recommend periodical monitoring of trace elements for long-term tube-fed patients with neurological dysphagia.

The role of rho and rho-dependent kinase in serotonin-induced contraction observed in bovine middle cerebral artery.

The current study was designed to characterize the role of Rho and Rho-dependent kinase (Rho-kinase) in isometric contractile responses induced by serotonin (5-HT) and a solution containing 40 mM K(+) (high K(+)) in ring preparations of the middle cerebral artery of bovine. Application of W-7, a Ca(2+)-calmodulin inhibitor, reversibly and equally attenuated the amplitudes of contractions produced by both 5-HT and high K(+). Similar effects were observed with ML-7, an inhibitor of myosin light chain kinase. Surprisingly, the protein kinase C inhibitors, calphostin C and Ro-31-8220, had no effect on the 5-HT-induced contraction. Incubation of preparations with Clostridium difficile toxin A and B or with Clostridium botulinum C3 exoenzyme for 48 hours attenuated the 5-HT-induced response but not the high K(+)-induced response. Application of the Rho-kinase inhibitor, Y-27632, resulted in marked inhibition of the 5-HT-induced response but had negligible effect on the high K(+)-induced response. These results suggest that the activation of Rho and Rho-kinase may be involved in the generation of the contraction produced by 5-HT in the bovine middle cerebral artery, while protein kinase C plays, if any, an insignificant role on the contraction.

Amino acid concentrations in the blood of the jugular vein and peripheral artery after traumatic brain injury: decreased release of glutamate into the jugular vein in the early phase.

The gross behavior of excitatory amino acids in patients with traumatic brain injury (TBI), including uptake, transport, metabolism, and clearance, was investigated by analysis of the levels of 41 amino acids in the blood of the jugular vein (JV), which is the primary venous drainage conduit of the brain, and a peripheral artery. Blood samples from the JV and a peripheral artery of eight patients with TBI were collected at 6 h, 6 to 24 h, and over 24 h after TBI, and analyzed using high performance liquid chromatography. Blood samples from 101 normal subjects were also measured. The levels of glutamate (Glu), gamma-aminobutyric acid (GABA), aspartate, glutamine, and cystine deviated from the normal range, and were considered pathological. The level of Glu in the JV was significantly lower than that in the artery (p < 0.05), and the level of GABA in the JV was significantly higher than that in the artery (p < 0.01), but the other three amino acids showed no significant differences. Significantly chronological changes in the difference between the blood levels in the JV and artery were observed for Glu. Measurement of the Glu level in the JV and artery may indicate gross metabolic change in the brain following TBI.