328,468 research outputs found
Intraoperative changes in blood coagulation and thrombelastographic monitoring in liver transplantation
The blood coagulation system of 66 consecutive patients undergoing consecutive liver transplantations was monitored by thrombelastograph and analytic coagulation profile. A poor preoperative coagulation state, decrease in levels of coagulation factors, progressive fibrinolysis, and whole blood clot lysis were observed during the preanhepatic and anhepatic stages of surgery. A further general decrease in coagulation factors and platelets, activation of fibrinolysis, and abrupt decrease in levels of factors V and VIII occurred before and with reperfusion of the homograft. Recovery of blood coagulability began 30-60 min after reperfusion of the graft liver, and coagulability had returned toward baseline values 2 hr after reperfusion. A positive correlation was shown between the variables of thrombelastography and those of the coagulation profile. Thrombelastography was shown to be a reliable and rapid monitoring system. Its use was associated with a 33% reduction of blood and fluid infusion volume, whereas blood coagulability was maintained without an increase in the number of blood product donors
Weak solutions to the continuous coagulation equation with multiple fragmentation
The existence of weak solutions to the continuous coagulation equation with
multiple fragmentation is shown for a class of unbounded coagulation and
fragmentation kernels, the fragmentation kernel having possibly a singularity
at the origin. This result extends previous ones where either boundedness of
the coagulation kernel or no singularity at the origin for the fragmentation
kernel were assumed
Genome-Wide Multiple Sclerosis Association Data and Coagulation
The emerging concept of a crosstalk between hemostasis, inflammation, and immune system prompt recent works on coagulation cascade in multiple sclerosis (MS). Studies on MS pathology identified several coagulation factors since the beginning of the disease pathophysiology: fibrin deposition with breakdown of blood brain barrier, and coagulation factors within active plaques may exert pathogenic role, especially through the innate immune system. Studies on circulating coagulation factors showed complex imbalance involving several components of hemostasis cascade (thrombin, factor X, factor XII). To analyze the role of the coagulation process in connection with other pathogenic pathways, we implemented a systematic matching of genome-wide association studies (GWAS) data with an informative and unbiased network of coagulation pathways. Using MetaCore (version 6.35 build 69300, 2018) we analyzed the connectivity (i.e., direct and indirect interactions among two networks) between the network of the coagulation process and the network resulting from feeding into MetaCore the MS GWAS data. The two networks presented a remarkable over-connectivity: 958 connections vs. 561 expected by chance; z-score = 17.39; p-value < 0.00001. Moreover, genes coding for cluster of differentiation 40 (CD40) and plasminogen activator, urokinase (PLAU) shared both networks, pointed to an integral interplay between coagulation cascade and main pathogenic immune effectors. In fact, CD40 pathways is especially operative in B cells, that are currently a major therapeutic target in MS field. The potential interaction of PLAU with a signal of paramount importance for B cell pathogenicity, such as CD40, suggest new lines of research and pave the way to implement new therapeutic targets
Effect of Escherichia coli endotoxin on Archachatina marginata haemolymph coagulation system
The effect of _E. coli_ endotoxin on the heamolymph coagulation response of _Archachatina marginata_ was studied. Heamocyte Lysate(HL), Haemocyte Lysate Supernatant(HLS) and Haemocyte Lysate Debris (HLD) were exposed to _Escherichia coli_ endotoxin. Controls were prepared with endotoxin-free water(<0.025 EU/ml). The differential protein coagulation was estimated in each mixture. Fractions of the haemolymph exposed to endotoxin produced higher protein coagulates than endotoxin-free fractions when incubated at 37 °C for 1 h (p<0.05). The results showed significantly higher (p<0.05) concentrations of protein coagulated when HL/plasma mixture were used than when either fraction was used. At a ratio 1:1 of HL:Plasma, highest protein coagulation was recorded. This study revealed that maximum protein coagulation in response to endotoxin was elicited by a synergy between plasma and haemocyte lysate(HL). From this research haemolymph fractions of Archachatina marginata may provide an alternative test material for endotoxin in medical preparations in the future
Phase transition of the one-dimensional coagulation-production process
Recently an exact solution has been found (M.Henkel and H.Hinrichsen,
cond-mat/0010062) for the 1d coagulation production process: 2A ->A, A0A->3A
with equal diffusion and coagulation rates. This model evolves into the
inactive phase independently of the production rate with density
decay law. Here I show that cluster mean-field approximations and Monte Carlo
simulations predict a continuous phase transition for higher
diffusion/coagulation rates as considered in cond-mat/0010062. Numerical
evidence is given that the phase transition universality agrees with that of
the annihilation-fission model with low diffusions.Comment: 4 pages, 4 figures include
Charging and Growth of Fractal Dust Grains
The structure and evolution of aggregate grains formed within a plasma
environment are dependent upon the charge acquired by the micron-sized dust
grains during the coagulation process. The manner in which the charge is
arranged on developing irregular structures can affect the fractal dimension of
aggregates formed during collisions, which in turn influences the coagulation
rate and size evolution of the dust within the plasma cloud. This paper
presents preliminary models for the charge and size evolution of fractal
aggregates immersed in a plasma environment calculated using a modification to
the orbital-motion-limited (OML) theory. Primary electron and ion currents
incident on points on the aggregate surface are determined using a
line-of-sight (LOS) approximation: only those electron or ion trajectories
which are not blocked by another grain within the aggregate contribute to the
charging current. Using a self-consistent iterative approach, the equilibrium
charge and dipole moment are calculated for the dust aggregate. The charges are
then used to develop a heuristic charging scheme which can be implemented in
coagulation models. While most coagulation theories assume that it is difficult
for like-charged grains to coagulate, the OML_LOS approximation indicates that
the electric potentials of aggregate structures are often reduced enough to
allow significant coagulation to occur
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