314 research outputs found
Observations of Chromospheric Anemone Jets with Hinode SOT and Hida Ca II Spectroheliogram
We present the first simultaneous observations of chromospheric "anemone"
jets in solar active regions with Hinode SOT Ca II H broadband filetergram and
Ca II K spetroheliogram on the Domeless Solar Telescope (DST) at Hida
Observatory. During the coordinated observation, 9 chromospheric anemone jets
were simultaneously observed with the two instruments. These observations
revealed three important features, i.e.: (1) the jets are generated in the
lower chromosphere, (2) the length and lifetime of the jets are 0.4-5 Mm and
40-320 sec, (3) the apparent velocity of the jets with Hinode SOT are 3-24
km/s, while Ca II K3 component at the jets show blueshifts (in 5 events) in the
range of 2- 6 km/s. The chromospheric anemone jets are associated with mixed
polarity regions which are either small emerging flux regions or moving
magnetic features. It is found that the Ca II K line often show red or blue
asymmetry in K2/K1 component: the footpoint of the jets associated with
emerging flux regions often show redshift (2-16 km/s), while the one with
moving magnetic features show blueshift (around 5 km/s). Detailed analysis of
magnetic evolution of the jet foaming regions revealed that the reconnection
rate (or canceling rate) of the total magnetic flux at the footpoint of the
jets are of order of 10^{16} Mx/s, and the resulting magnetic energy release
rate (1.1-10) x 10^{24} erg/s, with the total energy release (1-13) x 10^{26}
erg for the duration of the magnetic cancellations, 130s. These are comparable
to the estimated total energy, 10^{26} erg, in a single chromospheric anemone
jet. An observation-based physical model of the jet is presented. The relation
between chromospheric anemone jets and Ellerman bombs is discussed.Comment: 22 pages, 27 figures, accepted for Publications of the Astronomical
Society of Japa
Low Serum Concentrations of Vitamin B6 and Iron Are Related to Panic Attack and Hyperventilation Attack
Patients undergoing a panic attack (PA) or a hyperventilation attack (HVA) are sometimes admitted to emergency departments (EDs). Reduced serotonin level is known as one of the causes of PA and HVA. Serotonin is synthesized from tryptophan. For the synthesis of serotonin, vitamin B6 (Vit B6) and iron play important roles as cofactors. To clarify the pathophysiology of PA and HVA, we investigated the serum levels of vitamins B2, B6, and B12 and iron in patients with PA or HVA attending an ED. We measured each parameter in 21 PA or HVA patients and compared the values with those from 20 volunteers. We found that both Vit B6 and iron levels were significantly lower in the PA/HVA group than in the volunteer group. There was no significant difference in the serum levels of vitamins B2 or B12. These results suggest that low serum concentrations of Vit B6 and iron are involved in PA and HVA. Further studies are needed to clarify the mechanisms involved in such differences
Enhanced Hematopoiesis by Hematopoietic Progenitor Cells Lacking Intracellular Adaptor Protein, Lnk
Hematopoietic stem cells (HSCs) give rise to variety of hematopoietic cells via pluripotential progenitors and lineage-committed progenitors and are responsible for blood production throughout adult life. Amplification of HSCs or progenitors represents a potentially powerful approach to the treatment of various blood disorders and to applying gene therapy by bone marrow transplantation. Lnk is an adaptor protein regulating the production of B cells. Here we show that Lnk is also expressed in hematopoietic progenitors in bone marrow, and that in the absence of Lnk, the number and the hematopoietic ability of progenitors are significantly increased. Augmented growth signals through c-Kit partly contributed to the enhanced hematopoiesis by lnk−/− cells. Lnk was phosphorylated by and associated with c-Kit, and selectively inhibited c-Kit–mediated proliferation by attenuating phosphorylation of Gab2 and activation of mitogen-activated protein kinase cascade. These observations indicate that Lnk plays critical roles in the expansion and function of early hematopoietic progenitors, and provide useful clues for the amplification of hematopoietic progenitor cells
The Incidence and Prognostic Value of Hypochloremia in Critically Ill Patients
Little is known on the clinical effects of chloride on critically ill patients. We conducted this retrospective, observational study in 488 critically ill patients to investigate the incidence of chloride abnormalities, effects of hypochloremia in acid-base disorders, and association between chloride and clinical outcome. The study involved retrieval of arterial blood gas analyses, biochemical and demographical data from electrical records as well as quantitative acid-base analyses. For statistical analysis, the patients were stratified into three groups according to their chloride level (normal range: 98–106 mEq/L). The distribution of chloride levels was hyperchloremia 16.6%, normochloremia 74.6%, and hypochloremia 8.8%. The hypochloremic group was significantly alkalemic (P < 0.0001) and has significantly higher apparent strong ion difference (SIDa) (P < 0.0001) compared to the two other groups. The hypochloremic group had significantly longer stays in the ICU and hospital (P < 0.0001) with higher mortality (P < 0.0001). However, multiple regression analysis showed that chloride was not an independent factor of poorer outcome. In conclusion, the acid-base characteristics of the hypochloremic patients were alkalemia coexisting with higher SIDa. And although it was not an independent prognostic factor, hypochloremia was related to poorer outcome in critically ill settings
Alcohols increase calmodulin affinity for Ca2+ and decrease target affinity for calmodulin
AbstractIt has been proposed that alcohols and anesthetics selectively inhibit proteins containing easily disrupted motifs, e.g., α-helices. In this study, the calcineurin/calmodulin/Ca2+ enzyme system was used to examine the effects of alcohols on calmodulin, a protein with a predominantly α-helical structure. Calcineurin phosphatase activity and Ca2+ binding were monitored as indicators of calmodulin function. Alcohols inhibited enzyme activity in a concentration-dependent manner, with two-, four- and five-carbon n-alcohols exhibiting similar leftward shifts in the inhibition curves for calmodulin-dependent and -independent activities; the former was slightly more sensitive than the latter. Ca2+ binding was measured by flow dialysis as a direct measure of calmodulin function, whereas, with the addition of a binding domain peptide, measured calmodulin–target interactions. Ethanol increased the affinity of calmodulin for Ca2+ in the presence and absence of the peptide, indicating that ethanol stabilizes the Ca2+ bound form of calmodulin. An increase in Ca2+ affinity was detected in a calmodulin binding assay, but the affinity of calmodulin for calcineurin decreased at saturating Ca2+. These data demonstrate that although specific regions within proteins may be more sensitive to alcohols and anesthetics, the presence of α-helices is unlikely to be a reliable indicator of alcohol or anesthetic potency
The close relationship between decreases in extracellular GABA concentrations and increases in the incidence of hyperbaric oxygen-induced electrical discharge.
To elucidate the mechanism by which hyperbaric oxygen (HBO2) induces electrical discharge, changes in the extracellular concentrations of GABA and glutamate were measured every 5 min using a microdialysis technique in rats during a period of exposure to HBO2 (5 atm abs). Electrical discharge was observed at 28 +/- 4 min after the onset of exposure. Though the extracellular concentrations of glutamate remained unchanged, the extracellular GABA concentrations (pre-exposure level, 0.026 +/- 0.005 microM in dialysate) began to decrease 15 min after the onset of exposure and reached their lowest level (74 +/- 14%, 0.019 +/- 0.004 microM) at the time of appearance of the discharge. There was a close logistic relationship between extracellular GABA concentrations and the discharge incidence, and the extracellular concentrations of GABA causing electrical discharge in 50% of the animals were estimated to be 80% of the pre-exposure level. These results suggest a possible mechanism that HBO2 exposure-induced discharge is caused by the decrease in extracellular concentration of GABA.</p
The Excitement of Multiple Noradrenergic Cell Groups in the Rat Brain Related to Hyperbaric Oxygen Seizure
The mechanism of oxygen toxicity for central nervous system and hyperbaric oxygen (HBO) seizure has not been clarified. Noradrenergic cells in the brain may contribute to HBO seizure. In this study, we defined the activation of noradrenergic cells during HBO exposure by c-fos immunohistochemistry. Electroencephalogram electrodes were pre-implanted in all animals under general anesthesia. In HBO seizure animals, HBO was induced with 5 atm of 100% oxygen until manifestation of general tonic convulsion. HBO non-seizure animals were exposed to 25 min of HBO. Control animals were put in the chamber for 120 min without pressurization. All animals were processed for c-fos immunohistochemical staining. All animals in the HBO seizure group showed electrical discharge on EEG. In the immunohistochemistry, c-fos was increased in the A1, A2 and A6 cells of the HBO seizure group, and in the A2 and A6 cells of the HBO non-seizure group, yet was extremely low in all three cell types in the control group. These results suggest the participation of noradrenaline in HBO seizure, which can be explained by the early excitement of A1 cells due to their higher sensitivity to high blood pressure, hyperoxia, or by the post-seizure activation of all noradrenergic cells
Antinociceptive Effects of Intrathecal Landiolol Injection in a Rat Formalin Pain Model
Perioperative beta-blocker administration has recently been recommended for patients undergoing cardiac or other surgery due to the beneficial cardiovascular effects of these agents. In addition, some studies have reported that perioperatively administered beta-blockers also have analgesic effects. In this study, to investigate the antinociceptive effects and the analgesic profile of landiolol, we examined the effects of intrathecal landiolol administration on nociceptive pain behavior and c-fos mRNA expression (a neural marker of pain) in the spinal cord using a rat formalin model. We found that pain-related behavior was inhibited by intrathecal landiolol administration. Moreover, the increase in c-fos mRNA expression on the formalin-injected side was less pronounced in rats administered landiolol
than in saline administered controls. Thus, intrathecal administration of landiolol exhibited antinociceptive
effects. Further investigation of the antinociceptive mechanism of landiolol is required
Combinatorial Miller-Morita-Mumford classes and Witten cycles
We obtain a combinatorial formula for the Miller-Morita-Mumford classes for
the mapping class group of punctured surfaces and prove Witten's conjecture
that they are proportional to the dual to the Witten cycles. The
proportionality constant is shown to be exactly as conjectured by Arbarello and
Cornalba [J. Alg. Geom. 5 (1996) 705-749]. We also verify their conjectured
formula for the leading coefficient of the polynomial expressing the Kontsevich
cycles in terms of the Miller-Morita-Mumford classes.Comment: Published by Algebraic and Geometric Topology at
http://www.maths.warwick.ac.uk/agt/AGTVol4/agt-4-23.abs.htm
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