Sugar-free, glycine-stabilized intravenous immunoglobulin prevents skin but not renal disease in the MRL/lpr mouse model of systemic lupus.

Intravenous immunoglobulin (IVIG) has a therapeutic potential in many autoimmune diseases. Based on its immune modulating and complement inhibiting effects, IVIG has been tested in systemic lupus erythematosus (SLE), but due to osmotic tubular injury caused by immunoglobulin-stabilizing sugar components, lupus nephritis had been accelerated in some patients, thus IVIG use in SLE has been abandoned. The availability of non-sugar-stabilized IVIG raised the possible re-evaluation of IVIG for SLE. We investigated high-dose, long-term non-sugar-stabilized IVIG treatment on skin and renal SLE manifestations in the MRL/lpr mouse model. Animals were treated once a week with glycine-stabilized IVIG or saline (0.2 ml/ 10 g BW) from 6 weeks until they were humanely killed at 5 months of age. IVIG diminished macroscopic cutaneous lupus compared with saline treated mice. Histology and complement-3 immunostaining also demonstrated a significant reduction of skin disease after IVIG treatment. However, renal histology and function were similar in both groups. Compared with typical osmotic tubular damage induced by 5% sucrose and 10% maltose (used for IVIG stabilization), we did not observe any osmotic tubular injury in the glycine-stabilized IVIG treated mice. Our data demonstrate a beneficial effect of IVIG on skin lupus without renal side-effects. Deeper understanding of the organ-specific pathomechanism may aid an individualized SLE therapy.

Width of reaction zones in A+B-->C type reaction-diffusion processes: effects of an electric current.

We investigate the effects of an electric current on the width of a stationary reaction zone in an irreversible A(-)+B(+)-->C reaction-diffusion process. The ion dynamics of electrolytes A identical with (A(+),A(-)) and B identical with (B(+),B(-)) is described by reaction-diffusion equations obeying local electroneutrality and the stationary state is obtained by employing reservoirs of fixed electrolyte concentrations at the opposite ends of a finite domain. We find that the width of the reaction zone decreases when the current drives the reacting ions toward the reaction zone while it increases in the opposite case. The linear response of the width to the current is estimated by developing a phenomenological theory based on conservation laws and on electroneutrality. The theory is found to reproduce numerical solutions to a good accuracy.

Maximal height statistics for 1/f(alpha) signals.

Numerical and analytical results are presented for the maximal relative height distribution of stationary periodic Gaussian signals (one-dimensional interfaces) displaying a 1/f(alpha) power spectrum. For 01 (regime of strong correlations) and a highly accurate picture gallery of distribution functions can be constructed numerically. Analytical results can be obtained in the limit alpha-->infinity and, for large alpha, by perturbation expansion. Furthermore, using path integral techniques we derive a trace formula for the distribution function, valid for alpha=2n even integer. From the latter we extract the small argument asymptote of the distribution function whose analytic continuation to arbitrary alpha>1 is found to be in agreement with simulations. Comparison of the extreme and roughness statistics of the interfaces reveals similarities in both the small and large argument asymptotes of the distribution functions.

Extreme statistics for time series: distribution of the maximum relative to the initial value.

The extreme statistics of time signals is studied when the maximum is measured from the initial value. In the case of independent, identically distributed (iid) variables, we classify the limiting distribution of the maximum according to the properties of the parent distribution from which the variables are drawn. Then we turn to correlated periodic Gaussian signals with a 1/falpha power spectrum and study the distribution of the maximum relative height with respect to the initial height (MRHI). The exact MRHI distribution is derived for alpha=0 (iid variables), alpha=2 (random walk), alpha=4 (random acceleration), and alpha=infinity (single sinusoidal mode). For other, intermediate values of alpha , the distribution is determined from simulations. We find that the MRHI distribution is markedly different from the previously studied distribution of the maximum height relative to the average height for all alpha. The two main distinguishing features of the MRHI distribution are the much larger weight for small relative heights and the divergence at zero height for alpha>3. We also demonstrate that the boundary conditions affect the shape of the distribution by presenting exact results for some nonperiodic boundary conditions. Finally, we show that, for signals arising from time-translationally invariant distributions, the density of near extreme states is the same as the MRHI distribution. This is used in developing a scaling theory for the threshold singularities of the two distributions.

Guiding fields for phase separation: controlling Liesegang patterns.

Liesegang patterns emerge from precipitation processes and may be used to build bulk structures at submicrometer length scales. Thus they have significant potential for technological applications provided adequate methods of control can be devised. Here we describe a simple, physically realizable pattern control based on the notion of driven precipitation, meaning that the phase separation is governed by a guiding field such as, for example, a temperature or pH field. The phase separation is modeled through a nonautonomous Cahn-Hilliard equation whose spinodal is determined by the evolving guiding field. Control over the dynamics of the spinodal gives control over the velocity of the instability front that separates the stable and unstable regions of the system. Since the wavelength of the pattern is largely determined by this velocity, the distance between successive precipitation bands becomes controllable. We demonstrate the above ideas by numerical studies of a one-dimensional system with a diffusive guiding field. We find that the results can be accurately described by employing a linear stability analysis (pulled-front theory) for determining the velocity-local-wavelength relationship. From the perspective of the Liesegang theory, our results indicate that the so-called revert patterns may be naturally generated by diffusive guiding fields.

Synchronization landscapes in small-world-connected computer networks.

Motivated by a synchronization problem in distributed computing we studied a simple growth model on regular and small-world networks, embedded in one and two dimensions. We find that the synchronization landscape (corresponding to the progress of the individual processors) exhibits Kardar-Parisi-Zhang-like kinetic roughening on regular networks with short-range communication links. Although the processors, on average, progress at a nonzero rate, their spread (the width of the synchronization landscape) diverges with the number of nodes (desynchronized state) hindering efficient data management. When random communication links are added on top of the one and two-dimensional regular networks (resulting in a small-world network), large fluctuations in the synchronization landscape are suppressed and the width approaches a finite value in the large system-size limit (synchronized state). In the resulting synchronization scheme, the processors make close-to-uniform progress with a nonzero rate without global intervention. We obtain our results by "simulating the simulations," based on the exact algorithmic rules, supported by coarse-grained arguments.

Fisher waves and front roughening in a two-species invasion model with preemptive competition.

We study front propagation when an invading species competes with a resident; we assume nearest-neighbor preemptive competition for resources in an individual-based, two-dimensional lattice model. The asymptotic front velocity exhibits an effective power-law dependence on the difference between the two species' clonal propagation rates (key ecological parameters). The mean-field approximation behaves similarly, but the power law's exponent slightly differs from the individual-based model's result. We also study roughening of the front, using the framework of nonequilibrium interface growth. Our analysis indicates that initially flat, linear invading fronts exhibit Kardar-Parisi-Zhang (KPZ) roughening in one transverse dimension. Further, this finding implies, and is also confirmed by simulations, that the temporal correction to the asymptotic front velocity is of O(t(-2/3)).

Finite-size corrections to scaling of the magnetization distribution in the two-dimensional XY model at zero temperature.

The zero-temperature, classical XY model on an L×L square lattice is studied by exploring the distribution Φ_{L}(y) of its centered and normalized magnetization y in the large-L limit. An integral representation of the cumulant generating function, known from earlier works, is used for the numerical evaluation of Φ_{L}(y), and the limit distribution Φ_{L→∞}(y)=Φ_{0}(y) is obtained with high precision. The two leading finite-size corrections Φ_{L}(y)-Φ_{0}(y)≈a_{1}(L)Φ_{1}(y)+a_{2}(L)Φ_{2}(y) are also extracted both from numerics and from analytic calculations. We find that the amplitude a_{1}(L) scales as ln(L/L_{0})/L^{2} and the shape correction function Φ_{1}(y) can be expressed through the low-order derivatives of the limit distribution, Φ_{1}(y)=[yΦ_{0}(y)+Φ_{0}^{'}(y)]^{'}. Thus, Φ_{1}(y) carries the same universal features as the limit distribution and can be used for consistency checks of universality claims based on finite-size systems. The second finite-size correction has an amplitude a_{2}(L)∝1/L^{2} and one finds that a_{2}Φ_{2}(y)≪a_{1}Φ_{1}(y) already for small system size (L>10). We illustrate the feasibility of observing the calculated finite-size corrections by performing simulations of the XY model at low temperatures, including T=0.

Characteristics of lymphocytes and granulocytes removed from whole blood by buffy coat depletion. Comparison of an automated bottom-and-Top processing system and the manual technique.

BACKGROUND: Characteristics of lymphocyte and granulocyte removal were studied during the processing of fresh human blood by buffy coat (BC) depletion. The manual technique of BC depletion and that performed in a bottom-and-top (BAT) semiautomated system were compared. Blood cells were counted in the resulting components. RESULTS: Removal efficiency in lymphocytes and granulocytes correlated to the loss of erythrocytes due to removal of the BC. Sigmoidal curves showed good fit to experimental data. Variables of the equations differed substantially concerning removal of lymphocytes and granulocytes. The bottom-and-top bag in the semiautomated system resulted in better efficiency in leukocyte removal compared to the conventional manual technique.98% of lymphocytes may be removed from whole blood in the semiautomated BAT system. Removal efficiency of granulocytes is inferior compared to that of lymphocytes. Performance characteristics of the semiautomated BAT technique appeared superior when compared to the conventional manual technique. CONCLUSIONS: Substantial variability was observed in granulocyte removal efficiency in both systems. The present study may contribute to the production of erythrocyte preparations with less contaminating leukocytes and to standardize semiautomated blood processing.

Increased yield of F VIII from pooled plasma vs. single-donor plasma in the production of cryoprecipitates.

Coagulation factor VIII:C yield was studied in two types of cryoprecipitates. The first group contained products from single-donor plasma units. The other group contained cryoprecipitates which were produced from pooled plasma. The volume of plasma/bag was not different between the two groups, but both the yield and the total content of F VIII:C in cryoprecipitates were significantly different. The yield of F VIII:C was higher (+20% in relative terms) in cryoprecipitates produced from pooled plasma, resulting in higher potency of such products. The positive effect of plasma pooling on the recovery of F VIII:C might be a result of reassembly of factor VIII subunits of different individuals in the plasma pools. The findings may have a role also in large-scale production of F VIII concentrates.

Dynamic scaling of fronts in the quantum XX chain.

The dynamics of the transverse magnetization in the zero-temperature XX chain is studied with emphasis on fronts emerging from steplike initial magnetization profiles. The fronts move with fixed velocity and display a staircase like internal structure whose dynamic scaling is explored both analytically and numerically. The front region is found to spread with time subdiffusively with the height and the width of the staircase steps scaling as t(-1/3) and t(1/3), respectively. The areas under the steps are independent of time; thus the magnetization relaxes in quantized "steps" of spin flips.

Roughness distributions for 1/f alpha signals.

The probability density function (PDF) of the roughness, i.e., of the temporal variance, of 1/f(alpha) noise signals is studied. Our starting point is the generalization of the model of Gaussian, time periodic, 1/f noise, discussed in our recent Letter [Phys. Rev. Lett. 87, 240601 (2001)], to arbitrary power law. We investigate three main scaling regions (alpha < or = 1/2, 1/2 < alpha < or = 1, and 1< alpha), distinguished by the scaling of the cumulants in terms of the microscopic scale and the total length of the period. Various analytical representations of the PDF allow for a precise numerical evaluation of the scaling function of the PDF for any alpha. A simulation of the periodic process makes it possible to study also nonperiodic, thus experimentally more relevant, signals on relatively short intervals embedded in the full period. We find that for alpha < or = 1/2 the scaled PDFs in both the periodic and the nonperiodic cases are Gaussian, but for alpha > 1/2 they differ from the Gaussian and from each other. Both deviations increase with growing alpha. That conclusion, based on numerics, is reinforced by analytic results for alpha = 2 and alpha-->infinity, in the latter limit the scaling function of the PDF being finite for periodic signals, but developing a singularity for the aperiodic ones. Finally, an overview is given for the scaling of cumulants of the roughness and the various scaling regions in arbitrary dimensions. We suggest that our theoretical and numerical results open a different perspective on the data analysis of 1/f(alpha) processes.

Magnetization distribution in the transverse Ising chain with energy flux.

The zero-temperature transverse Ising chain carrying an energy flux j(E) is studied with the aim of determining the nonequilibrium distribution functions, P(M(z)) and P(Mx) of its transverse and longitudinal magnetizations, respectively. An exact calculation reveals that P(M(z)) is a Gaussian both at j(E)=0 and at j(E) not equal to 0, and the width of the distribution decreases with increasing energy flux. The distribution of the order-parameter fluctuations, P(Mx), is evaluated numerically for spin chains of up to 20 spins. For the equilibrium case (j(E)=0), we find the expected Gaussian fluctuations away from the critical point, while the critical order-parameter fluctuations are shown to be non-Gaussian with a scaling function Phi(x)=Phi(M(x)/)=P(Mx) strongly dependent on the boundary conditions. When j(E) not equal to 0, the system displays long-range, oscillating correlations but P(Mx) is a Gaussian nevertheless, and the width of the Gaussian decreases with increasing j(E). In particular, we find that, at critical transverse field, the width has a j(-3/8)(E) asymptotic in the j(E)-->0 limit.

Width distributions and the upper critical dimension of Kardar-Parisi-Zhang interfaces.

Simulations of restricted solid-on-solid growth models are used to build the width distributions of d=2-5 dimensional Kardar-Parisi-Zhang (KPZ) interfaces. We find that the universal scaling function associated with the steady-state width distribution changes smoothly as d is increased, thus strongly suggesting that d=4 is not an upper critical dimension for the KPZ equation. The dimensional trends observed in the scaling functions indicate that the upper critical dimension is at infinity.

Statistics of extremal intensities for Gaussian interfaces.

The extremal Fourier intensities are studied for stationary Edwards-Wilkinson-type, Gaussian, interfaces with power-law dispersion. We calculate the probability distribution of the maximal intensity and find that, generically, it does not coincide with the distribution of the integrated power spectrum (i.e., roughness of the surface), nor does it obey any of the known extreme statistics limit distributions. The Fisher-Tippett-Gumbel limit distribution is, however, recovered in three cases: (i) in the nondispersive (white noise) limit, (ii) for high dimensions, and (iii) when only short-wavelength modes are kept. In the last two cases the limit distribution emerges in nonconventional scenarios.

Importance of platelet functions in Alzheimer's disease.

The function of platelets of patients with Alzheimer's disease has been characterized. The shape of platelets is more spherical and the initial rate of platelet aggregation caused by different agonists measured in plasma is faster in the case of Alzheimer's disease and senile dementia of the Alzheimer-type than that of other demented patients: multi infarct dementia and probable vascular dementia. Although fast aggregation is characteristic of activated platelets but the Alzheimer platelets are not hypersensitive. The activation of Alzheimer platelets makes the velocity of ADP induced aggregation slower and it is different than the behaviour of normal activated platelets. The shape-associated parameter and the initial rate of 50 microM ADP-induced aggregation of platelets non-activated and activated by cytochrome C are recommended for establishing the diagnosis of Alzheimer's disease and senile dementia of the Alzheimer-type. The evaluation of these parameters has been discussed. The cytochrome C may be useful to normalize the function of Alzheimer platelets in plasma, not only in vitro.

Technical aspects of buffy coat removal from whole blood and those of platelet production from single buffy coat units.

Technical aspects of buffy coat removal and those of platelet production from the buffy coat were studied using the so-called Amsterdam technique. A long stomach clamp physically separates the buffy coat from erythrocyte concentrate. A better removal of platelets and leukocytes was obtained when blood stored overnight was processed vs. fresh blood. As 71.4 +/- 16.4% of leukocytes was removed from blood stored overnight, it resulted in a mean leukocyte content of 0.84 +/- 0.52 x 10(-9) of the erythrocyte concentrate. The haematocrit of the single buffy coat units have an essential impact on platelet production from buffy coat. A haematocrit of less than 30% seems to be preferable with a volume over 100 ml. The leukocyte contamination of the platelet concentrate is less when it is produced from blood stored overnight.

[Glucose content in blood products]. / Vérkészítmények glukóztartalma.

The glucose content of the main blood products used in Hungary was determined, because the amount of glucose administred together with the blood products may have significance, especially at diabetic patients. The results revealed that there is a substantial difference in the glucose content of the different blood products and the glucose content of the individual products of the same kind may have also substantial difference. The glucose content of cell products depends also on the storage time. Washed red cell products can be ordered in glucose-free form, that is resuspended in glucose-free resuspension medium. Leukocyte concentrate contains hydroxyethyl starch, which will be hydrolysed into glucose in the circulation of the recipient.

[Biological aspects of the effectiveness/ineffectiveness of thrombocyte transfusions]. / A thrombocyta-transzfúziók hatásának/hatástalanságának biológiai problémái.

The clinical effect of platelet transfusions depends on a series of different factors and therefore it is not easy to explain the cause of inefficiency or that of the side-effects. Not only the immunhematological state of the patient, but the medical treatment and the properties of the platelet preparations should be taken into account. Platelet products prepared by standard techniques and stored according to the international recommendations possess different hemostatic effect. The effect of platelet storage conditions, aspects of platelet thermophysiology and current international tendencies regarding preparation and storage of platelet products are discussed. The choice of the proper platelet product has an essential impact on the clinical outcome.

[Blood products stored in plastic bags: release of plasticizers from the bag material]. / Vérkészítmények müanyag zsákban: lágyító kioldódás a zsákfalból.

The plasticizer di-(2-ethyl-hexyl)phthalate (DEHP) is slowly leached from the wall of the PVC blood bags into the blood products. It will be partly incorporated into the membranes of the blood cells, and finally will be transfused together with the blood products into the recipient, where DEHP might exert toxic effects. DEHP content was determined by HPLC in different blood products stored in plastic bags manufactured by different firms (Medicor--Hungary, MacoPharma--France, Terumo--Japan, Baxter--USA). In whole blood DEHP is present mainly in the plasma and blood bags of different firms show similar results. 1 unit of whole blood contains 20-50 mg DEHP on day 14 of storage, and 30-55 mg on day 28, while red blood cells resuspended in plasma contained only 2-15 mg on day 14. 15-20 mg DEHP was found in 1 unit of plasma stored for 4 days at +4 degrees C. Only 1-4 mg DEHP was detected in 1 unit of erythrocytes (cca. 200 ml) even on day 14 of storage. The supernatant of platelet concentrates contained the relatively highest amount of DEHP (even 50-65 mg was found in 1 unit of platelet concentrates on day 5 of storage). When platelet concentrates were studied, essential differences were recorded between the bags manufactured by different firms. Platelet reactivity is better maintained in storage bags manufactured without DEHP.