With the recent discoveries of massive and highly luminous quasars at high
redshifts ($z\sim7$; e.g. Mortlock et al. 2011), the question of how black
holes (BHs) grow in the early Universe has been ...cast in a new light. In order
to grow BHs with $M_{\rm BH} > 10^9$ M$_{\odot}$ by less than a billion years
after the Big Bang, mass accretion onto the low-mass seed BHs needs to have
been very rapid (Volonteri & Rees, 2005). Indeed, for any stellar remnant seed,
the rate required would need to exceed the Eddington limit. This is the point
at which the outward force produced by radiation pressure is equal to the
gravitational attraction experienced by the in-falling matter. In principle,
this implies that there is a maximum luminosity an object of mass $M$ can emit;
assuming spherical accretion and that the opacity is dominated by Thompson
scattering, this Eddington luminosity is $L_{\rm{E}} = 1.38 \times 10^{38}
(M/M_{\odot})$ erg s$^{-1}$. In reality, it is known that this limit can be
violated, due to non-spherical geometry or various kinds of instabilities.
Nevertheless, the Eddington limit remains an important reference point, and
many of the details of how accretion proceeds above this limit remain unclear.
Understanding how this so-called super-Eddington accretion occurs is of clear
cosmological importance, since it potentially governs the growth of the first
supermassive black holes (SMBHs) and the impact this growth would have had on
their host galaxies (`feedback') and the epoch of reionization, as well as
improving our understanding of accretion physics more generally.
Fifty-four horses with hoof cracks were referred to the Equine Hospital of the University of Zurich, for treatment. The horses were admitted because of lameness or other symptoms caused by the ...cracks. Deep or complicated quarter cracks were the most common type of cracks diagnosed. Poor conformation and abnormal hoof shape were the most important causes of hoof crack development, whereas injury to the coronary band was a less frequently encountered cause. Effective treatment of this problem includes corrective shoeing, removing horn from the weight-bearing surface as well as from the crack with a Dremel tool and immobilization of the borders of the crack. However, even with such a therapy, the recurrence rate of hoof cracks was with 20% very high.
This clinical study was performed to evaluate the effect of low-potassium dextran (LPD) solution on organ function in human lung transplantation.
A total of 80 patients were included in this study. ...Donor lungs were flushed with Euro-Collins (EC) solution in 48 cases or LPD (Perfadex) in 32 cases. Subsequently, single- (EC: n = 31; LPD: n = 15) or double-lung transplantations (EC: n = 17; LPD: n = 17) were performed. The evaluation parameters of transplant function were the reperfusion injury score (grade I to V); the alveolar/arterial oxygen ratio; the duration of respirator therapy; and the length of intensive care treatment and survival.
Incidence and severity of reperfusion injury score were more severe in the EC group (31 of 48: grade I: n = 13; II: n = 8; III: n = 5; IV: n = 2; V: n = 3; LPD group: 17 of 32 patients; grade I: n = 12; II: n = 1; III: n = 3; IV: n = 0 grade V: n = 0), leading to death in three patients. In the LPD group, despite of the use of cardiopulmonary bypass, alveolar/arterial oxygen ratio values were significantly (P = 0.009) better during the early postoperative phase. Thirty-day mortality was 12% in the EC group and 6% in the LPD group. The one-year survival rate was 79% after the use of LPD (vs. EC: 62%).
Graft preservation using LPD leads to better immediate and intermediate graft function after pulmonary transplantation and also results in better long-term survival.
A brief period of ischemia was used to evaluate an erythrocyte-enriched Krebs-Henseleit (KH) buffer (
n=8) compared to KH only (
n=8) in an isolated working rabbit heart. Experimental protocol was as ...follows: preischemic baseline, 5 min of global ischemia followed by 45 min of reperfusion. Preischemic heart rate was identical, coronary flow was significantly lower (2.7 versus 5.6 mL/min/g wet wt,
p<0.01), the other hemodynamic and biochemical values were significantly higher in erythrocyte-perfused hearts: aortic flow 23.5 versus 12.0,
p<0.01; cardiac output 26.2 versus 17.6,
p<0.01; all in mL/min/g wet wt; dp/dt max 1286 versus 997 mmHg/s,
p<0.01; myocardial oxygen consumption 3.5 versus 2.3 μmol/min/g wet wt,
p<0.05. During early reperfusion, in the erythrocyte-perfused hearts, coronary flow further increased (
p<0.003), the other hemodynamic parameters returned to baseline values in both groups. High-energy phosphates showed significantly higher values (ATP 2.0±0.1 versus 1.3±0.1,
p<0.05; CrP 2.0±0.2 versus 1.6±0.1,
p<0.05 all in μmol/g wct wt), water content was significantly lower (81% versus 74%,
p<0.05) in erythrocyte-perfused hearts. It can be concluded that the erythrocyte-perfused working heart model provides excellent oxygenation, leading to superior hemodynamic and metabolic performance. Additionally, in the erythrocyte-perfused hearts preservation of coronary flow reserve underlines the physiological competency of this prepar-ation.
Obliterative bronchiolitis (OB), the most important long-term complication after lung transplantation, is thought to be a manifestation of chronic rejection within the airways, with the hallmarks ...inflammation and fibroproliferation.
To characterize the inflammatory process in the context of OB we quantified tumor necrosis factor-alpha, interleukin (IL)-8, IL-10, and transforming growth factor (TGF)-beta on the protein and mRNA level in bronchoalveolar lavage fluid samples obtained from patients with bronchiolitis obliterans syndrome (BOS) and without BOS. In addition, bronchial cells sampled by bronchial brushing were analyzed for mRNA expression.
In respiratory epithelial lining fluid (ELF) from BOS patients the protein levels of IL-8 (52.4+/-22.2 vs. 4.4+/-0.9 pg/ml ELF, P<0.005) and TGF-beta (5.6+/-1.9 vs. 0.9+/-0.2 ng/ml ELF, P<0.005) were significantly elevated. In addition, bronchoalveolar lavage fluid cells of BOS patients showed increased expression of TGF-beta (1.13+/-0.44 vs. 0.45+/-0.16, optical density O.D./O.D. glyceraldehyde-3-phosphate dehydrogenase GAPDH, P=0.11) and IL-8 (0.25+/-0.13 vs. 0.09+/-0.03 O.D/O.D. GAPDH, P=0.53) without the differences reaching statistical significance. In contrast, IL-8 mRNA expression of bronchial cells was significantly higher in the BOS group (0.85+/-0.40 vs. 0.22+/-0.10 O.D./O.D. GAPDH, P<0.05).
We assume that IL-8 and TGF-beta may act as key mediators for airway inflammation and fibroproliferation in the pathogenesis of OB, with bronchial epithelial cells serving as a relevant source of IL-8.
A common side effect associated with succinylcholine is postoperative myalgia. The pathogenesis of this myalgia is still unclear; inflammation has been suggested but without convincing evidence. We ...designed the present study to investigate whether an inflammatory reaction contributes to this myalgia. The incidence and severity of succinylcholine-associated myalgia was determined in 64 patients pretreated with saline or dexamethasone before succinylcholine (n = 32 for each). Incidence and severity of myalgia did not differ significantly between the two groups: 15 patients in the dexamethasone group complained of myalgia compared with 18 patients in the saline group, and severe myalgia was reported by five patients and three patients, respectively (not significant). At 48 h after surgery, 12 patients in both groups still suffered from myalgia (not significant). In addition, interleukin-6 (IL-6) as an early marker of inflammation was assessed in a subgroup of 10 patients pretreated with saline. We found an increase of IL-6 for only three patients, but only one patient reported myalgia; no relationship between myalgia and the increase of IL-6 was found. In conclusion, there is no evidence for an inflammatory origin of succinylcholine-associated myalgia.
Administration of dexamethasone before succinylcholine was not effective in decreasing the incidence or the severity of succinylcholine-induced postoperative myalgia. Furthermore, there was no significant relationship between postoperative myalgia and time course of interleukin-6 concentrations, a marker of inflammation. Pretreatment with dexamethasone is not justified to prevent postoperative myalgia after succinylcholine.
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