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The effects of hydrostatic pressure on erythrocyte aggregation have been studied by laser photometry and analysis based on a phenomenological theory. Samples were prepared by suspending swine erythrocytes in their own plasma. A high-pressure vessel consisting of a stainless-steel block with a hole to hold a sample cell and two sapphire windows to allows the passage of a He-Ne laser beam was used in the experimental setup. The suspension was stirred at 1500 rpm to disperse the erythrocytes homogeneously. Immediately after reducing the stirring rate from 1500 rpm to 300 rpm, the transmitted light intensity (I) was recorded every 10 ms under a high pressure of 40-200 MPa. The value of I increased with time (t) owing to erythrocyte aggregation. From the phenomenological theory, the equation ΔI(t)=ΔIeq[1-e(-Kt)/(1-B(1-e(-Kt)))] was derived for the change in the transmitted light intensity (ΔI) due to erythrocyte aggregation, where ΔIeq is the transmitted light intensity in the steady state, K is a time constant and B is a constant that represents the ratio of the number of interaction sites on erythrocyte aggregates at time t to that in the steady state. The observed time courses of ΔI obtained at all pressures could be closely fitted to the theoretical equation. ΔIeq roughly increased with increasing pressure. On the other hand, K and B abruptly decreased above 120 MPa. The growth rate of aggregates decreased above 120 MPa. These results suggest a change in the mechanism of erythrocyte aggregation at approximately 120 MPa. We discuss the physical meaning of the parameters.

Blood coagulation capability is one of the most important factors for the diagnosis of patients with thrombosis. Regarding the blood coagulation as an example of gelation of soft matter, we can apply an analytical method to this phenomenon and pick up some relevant parameters. In various systems, gelation dynamics induced by contact between a polymer solution and a crosslinker solution are well explained by the “moving boundary picture” (Yamamoto et al., J. Phys. Chem. B, 2010, 114, 10002–10009). The aim of this paper is to clarify whether this picture can be applied to a clinically important biological system used for blood coagulation tests. We have measured the time course of the thickness of a plasma gel layer formed when plasma comes in contact with calcium chloride solution in a rectangular cell and analyzed theoretically on the basis of the moving boundary picture. The entire process was well expressed using a scaled equation involving three parameters characterizing the plasma, k, Kin, and β, where k is the time required to reach the incipient stage of three-dimensional network formation, the parameter Kin is proportional to calcium chloride concentration and β is a constant. These results indicate the direct applicability of the general theory of gelation dynamics induced by contact between two solutions to the in vitro coagulation (gelation) of plasma, and the fitting parameters may be used for diagnosis.

Cleavage of carbohydrate chains linked to fibrinogen molecule results in an acceleration of fibrin polymerization, fibrin gel formation, by promoting the lateral aggregation of protofibrils. Sialic acid at the unreduced terminus of carbohydrate chain plays an essentially important role in the lateral aggre-gation. Fibrin polymerization is significantly affected by the solvent condition, e.g., pH and ionic strength. Terminal sialic acid are supposed to interact with amino terminal region of Bβ chain, in which there are many basic amino acid residues, and thus such interactions are expected to be electrostatic. In order to clarify whether the electrostatic interactions are essential for lateral aggregation, we examined temporal growth of fibrin polymerization of deglycosylated fibrinogen at high NaCl concentration. Marked acceleration of lateral aggregation was observed in deglycosylated fibrinogen even at high NaCl concentration where lateral aggregation was significantly inhibited in intact fibrinogen. These results suggest specific interactions of terminal sialic acid of the carbohydrate chain with the central E region of fibrinogen molecule, which may be important for the regulation of lateral aggregation rather than electrostatic interactions between the terminal sialic acids and the amino terminal region of Bβ chain.

Acceleration of fibrin polymerization occurs by the cleavage of sialic acids at the nonreducing terminal ends of N-linked carbohydrate chains as well as the cleavage of the entity of carbohydrate chains. In order to characterize and clarify the role of terminal sialic acid in the fibrin polymerization, mixing effects of desialylated fibrinogen with the intact one on the polymerization behavior were investigated by turbidity measurements in the course of polymerization. Marked accelerated fibrin polymerization was observed for the mixing of even a little amount of desialylated fibrinogen. Cleavage of the terminal sialic acid resulted in almost the equivalent accelerating effect to those of the deglycosylated fibrinogen, in which the entity of N-linked carbohydrate chain was cleaved. These results suggest that the terminal sialic acids regulate the fibrin polymerization in an inhibitory manner, and the cleavage of them induces the switchover from the protofibril growth to the lateral aggregation of fibrin polymerization process, resulting in the preferential fibrin polymerization.

Fibrin polymerization proceeds in a stepwise manner. In the first step, fibrinogen-to-fibrin conversion is triggered by the enzymatic fibrinopeptide release and protofibril formation/growth proceeds. In the following second step, lateral aggregation of the protofibrils occurs resulting in the network formation. Switchover from the first step to the second one can regulate the resultant network structure, and the lateral aggregation is considered to be induced by the interaction between the αC regions of two adjacent protofibrils. In order to clarify the characteristics of this interaction, we examined the cross-sectional diameter DCin addition to the hydrodynamic diameter (Stoke diameter) of fibrinogen molecule in various solution conditions. Cross-sectional diameter of intact fibrinogen was 4.7 nm in agreement with the molecular structure. On the other hand, fragment-X, in which the αC regions are deleted, had smaller DCof 4.2 nm. This means that the αC regions snuggle up to the molecular backbone, which is consistent with the model that the termini of the αC regions are tethered to the central E-region in the intact fibrinogen. On the other hand, fibrinogen at pH 3 had a cross-sectional diameter of 4.0 nm, which is further smaller than that of fragment-X. This is accounted for by the scheme that the αC regions are released from the central region, because side chains of Asp and Glu residues have neutral charge at pH 3. With the increase of ionic strength up to 150 mM at pH 3, fibrinogen molecules become to aggregate resulting in huge aggregated particles. Our results suggest that the released αC regions can interact attractively with each other through the hydrophobic interaction, which supports the proposed scheme of fibrin polymerization.

The P2 phage virion has tail spike proteins beneath the baseplate and uses them to adsorb to the outer membrane of Escherichia coli during the infection process. Previous immunoelectron microscopic studies suggested that the tail spikes are composed of the gene V product (gpV); however, experimental evidence of its membrane binding activity has yet to be reported. In this study, we purified and characterized recombinant full-length gpV and its C-terminal domain. Limited chymotrypsin proteolysis of gpV produced a C-terminal domain composed of Ser86-Leu211. Our experiments demonstrated that the N- and C-terminal domains have very different melting temperatures: 50 and 74 degrees C, respectively. We also found that gpV binds the E. coli membrane via its C-terminal domain. We conclude that the C-terminal domain of gpV is a stable trimer and serves as the receptor-binding domain for the second step in the phage adsorption process.

Thermal response of N-isopropylacrylamide (NiPAM) gel particles of submicron size was investigated by means of ultrasonic velocity and density focusing on the hydration and dehydration behavior. Hydration number, defined as the number of water molecules bound to one NiPAM monomer unit, was quantitatively evaluated in the course of the volume phase transition. Hydration numbers at low and high temperatures were about 7.5 (20 °C) and 3 (40 °C), respectively. Hydration number decreases markedly near the volume phase transition temperature, and the decrease is responsible to the formation of hydrophobic bonding and dehydration. The hydration number is independent both of the size and the composition of gel particles in the shrunken state, although there exists a composition dependence in the swollen state. It was also found that the self-assemblies formed by hydrophobic interaction are more bulky compared to those in the hydrated state.

Using various types of DNAs prepared from plasmid DNA, complete double-stranded DNA (ds.DNA) with linear and cyclic forms and double-stranded DNA coexisting with single-stranded DNA (ss.DNA), the structure and fibrillogenesis of the collagen-DNA complex were investigated by means of turbidity, transmission electron microscopy, and confocal laser-scanning microscopy. The rate of fibrillogenesis of the collagen-DNA complex significantly depends on the DNA structure. The structure of the fibrils formed in the complexes showed a marked difference between the ds.DNA and ss.DNA complexes with collagen. Spatial distribution of the DNA and collagen in the complexes suggests that the characteristic collagen-DNA interaction depends on the DNA forms.

A digital apparatus was fabricated to determine accurately the erythrocyte sedimentation rate (ESR) using a linear image sensor. Currently, ESR is utilized for clinical diagnosis, and in the laboratory as one of the many rheological properties of blood through the settling of red blood cells (RBCs). In this work, we aimed to measure ESR automatically using a small amount of a sample and without moving parts. The linear image sensor was placed behind a microhematocrit tube containing 36 μl of RBC suspension on a holder plate; the holder plate was fixed on an optical bench together with a tungsten lamp and an opal glass placed in front. RBC suspensions were prepared in autologous plasma with hematocrit H from 25% to 44%. The intensity profiles of transmitted light in 36 μl of RBC suspension were detected using the linear image sensor and sent to a personal computer every minute. ESR was observed at the settling interface between the plasma and RBC suspension in the profile in 1024 pixels (25 μm/pixel) along...

The structure of the cell membrane of Ecemothecium ashbyii is considered to be one of the main obstacles in the improvement of riboflavin productivity, which impedes the release of riboflavin from the cell into the fermentation broth. The results of the present study show that stimulation on growth and riboflavin biosynthesis phase, the content of riboflavin was most obviously enhanced, as compared with the control and the total riboflavin quantity released by ultrasonic treatment. The optimal stimulation time was from 104 to 112 h and ultrasonic should be loaded every 1.5 h.

Environmental factors can greatly influence the growth of plants. In this paper, the effect of sound stimulation on the metabolism of chrysanthemum roots was studied and it was found that the growth of roots was not inhibited but accelerated under suitable sound stimulation. And the content of soluble sugar and protein and the activity of amylase all increased significantly, which indicated that sound stimulation could enhance the metabolism of roots and the growth of chrysanthemum.

Plants and environment are dependent on each other and environmental factors can greatly influence the growth and development of plant. Plasmalemma takes an important role in the process of signal transduction. The physical state of plasmalemma lipid and second structure of membrane protein can change with the process of signal transduction. In this paper, the effect of sound stimulation on the microstructure of plasmalemma was studied to explore the mechanism of biological effect of sound stimulation.

The effects of pressure on the aggregation of swine erythrocytes were investigated by monitoring the erythrocyte sedimentation rate under high pressure, up to 40 MPa. The aggregation of erythrocytes in plasma was propor-tionally enhanced by pressure, whereas aggregation of erythrocytes was not observed in saline solution up to 40 MPa. These results suggest that the adhesion energy between erythrocytes is not directly affected by pressure, but through a change in the interaction energy between plasma components and erythrocytes.

The growth process of swine erythrocyte aggregate was studied using microscopic observations and mathematical analysis. Both the cross-sectional area S and velocity V of an arbitrarily chosen aggregate in dilute suspension increased exponentially with time: S = S0 exp(tτs), V = V0 exp(tτv) with S0 = 160 μm2, V0 = 1.12 μm s−1, τs = 0.20 s and τv = 0.17 s. The average values of V and S for aggregates in suspension were proportional to each other and the proportionality constant deviates from the calculated value when aggregates are assumed to comprise homogeneous closely packed spheres. On the basis of these results and simple assumptions, a differential equation was derived for the number of aggregates consisting of n erythrocytes at time t, f(n, t): ∂f(n, t)∂t = − k[∂f(n, t)∂n + (ln 2)f(n, t)] The solution of this equation indicates that f(n, t) is a function of n − kt.

Bacteriophage Mu, which has a contractile tail, is one of the most famous genus of Myoviridae. It has a wide host range and is thought to contribute to horizontal gene transfer. The Myoviridae infection process is initiated by adhesion to the host surface. The phage then penetrates the host cell membrane using its tail to inject its genetic material into the host. In this penetration process, Myoviridae phages are proposed to puncture the membrane of the host cell using a central spike located beneath its baseplate. The central spike of the Mu phage is thought to be composed of gene 45 product (gp45), which has a significant sequence homology with the central spike of P2 phage (gpV). We determined the crystal structure of shortened Mu gp45Δ1-91 (Arg92–Gln197) at 1.5 A resolution and showed that Mu gp45 is a needlelike structure that punctures the membrane. The apex of Mu gp45 and that of P2 gpV contained iron, chloride, and calcium ions. Although the C-terminal domain of Mu gp45 was sufficient for binding to the E. coli membrane, a mutant D188A, in which the Asp amino acid residue that coordinates the calcium ion was replaced by Ala, did not exhibit a propensity to bind to the membrane. Therefore, we concluded that calcium ion played an important role in interaction with the host cell membrane.

In order to examine the role of αC domains, especially the terminal region of it, of fibrinogen Aα chain in the fibrin gel formation, we prepared a recombinant fibrinogen, Aα570 fibrinogen. Aα570 fibrinogen is the fibrinogen that is truncated at Aα570 and lacks 40 amino acids at the terminus of the αC domain. We examined the thrombin-catalyzed polymerization by transmission spectroscopy and confocal laser scanning microscopy (CLSM). We found that Aα570 fibrinogen exhibited a significantly delayed aggregation showing the importance of the terminal region of the αC domain in the polymerization process. Contrary to the fact that the addition of glucose to the mixture of fibrinogen and thrombin results in a substantial delay of the lateral aggregation of protofibrils for the native fibrinogen, delaying effect due to the addition of glucose disappeared thoroughly in the case of Aα570 fibrinogen. Turbidity measurements dependent upon the wavelength in the time course of gelation showed that mass per unit fiber length of Aα570 fibrinogen decreased significantly compared to the native fibrinogen, and the lateral aggregation of protofibrils was hindered significantly. Those results are consistent with the CLSM measurements that the bundles of protofibrils of Aα570 fibrinogen are thinner and denser with more branching than those of the native one. It was confirmed that C-terminal region of the αC domain plays an important role in the lateral aggregation and glucose interferes the interacting process between the αC domains.

Cyclic oligomers of glucose, termed cyclodextrins (CDs), can contain 6 (alpha-CD), 7 (beta-CD) or 8 (gamma-CD) glucose units and are able to remove cholesterol from platelet membranes and decrease platelet aggregation. The present study was designed to examine the effects of these CDs on RBC aggregation and blood viscosity. Blood from normal adult volunteers was incubated at 37 degrees C with 3.0 x 10(-4) to 1.5 mM levels of the CDs, then processed to obtain platelet-rich plasma, platelet poor plasma and 40% hematocrit blood; measurements included collagen-induced platelet aggregation, RBC aggregation (Myrenne Aggregometer) and blood viscosity at 1-1000 sec(-1)(Rheolog). Our results indicate the expected dose-dependent inhibition of platelet aggregation by beta-CD, with no significant effects of alpha-CD or gamma-CD. RBC aggregation studies showed no effect of alpha-CD but highly significant (p0.01) decreases by both beta-CD and gamma-CD; at the concentrations studied (1.5 x 10(-3) to 1.5 mM), beta-CD had somewhat greater effects. Blood viscosity was not affected by alpha-CD, but was significantly decreased in a dose-dependent manner by beta-CD and, at the highest concentration (1.5 mM), by gamma-CD. Interestingly, the effects of beta-CD and gamma-CD were independent of shear, with these effects not explained by the usual mechanisms. These results suggest the potential hemorheological value of CDs, yet also indicate the need for additional studies.

Gelation dynamics and gel structure of fibrinogen induced by serine protease, thrombin, was investigated by light scattering, real space observation using confocal laser scanning microscopy (CLSM), and turbidity. Effects of additives, such as (linear) saccharides, glucose to dextran, and cyclodextrin, were studied focusing on the interaction with fibrin(ogen) and thrombin. Light scattering measurement was ascertained to be able to characterize the gelation process and growth kinetics. Stepwise (two-step) gelation process, formation of fibrin monomers and protofibrils followed by the lateral aggregation to form fibrin fibers and gel network, was clearly ascertained. Gelation point could be characterized quantitatively. At the gelation point, dynamic light scattering exhibited a self-similar nature of the fibrin gel network, and the fractal dimension was evaluated in good accordance with the reconstructed 3D image of gel network by CLSM. The interaction between the additives and fibrin(ogen) and thrombin were studied by the inhibition test using synthesized substrate. Temporal variation of microstructure of fibrin gel network (lateral fiber growth) was investigated by turbidity in detail. Addition of saccharides affects significantly the network formation as revealed by turbidity. The interaction of dextran with fibrin fibers was examined by fluorescence microscopy, too, and the characteristic spatial distribution was observed.

Background: This study was done to investigate the effects of blood transfusion on gastrointestinal anastomotic wound healing and leukocyte function. Methods: Closed-colony male Wistar rats were divided into five groups in a group-mixed fashion and underwent laparotomy (the CONT and WB groups) or gastrectomy and gastroduodenostomy (the GAST, GAST/WB and GAST/LDRWB groups). Immediately, they received 3 ml of saline (the CONT and GAST groups) or blood from Wistar donors (the WB and GAST/WB groups, whole blood; the GAST/LDRWB group, a transfusion of irradiated and leukocyte-depleted whole blood). The animals were killed 7 days after surgery. Results: The GAST/WB group had a higher incidence of anastomotic abscess, a lower level of factor XIII and a lower maximum breaking strength than the GAST group. Gastrectomy decreased L-DCL (luminol-dependent chemiluminescence) more than whole-blood transfusion. In the GAST/WB group, L-DCL was severely reduced, while in the GAST/LDRWB group it was roughly equivalent to the level in the GAST group. Conclusions: Whole-blood transfusion increased the incidence of anastomotic abscess and impaired anastomotic wound healing, and these might relate to the reduction of L-DCL. Irradiated and leukocyte-depleted transfusion can improve these effects.

The enhanced rate of sedimentation of erythrocytes in an inclined rectangular vessel was measured under microscopic and macroscopic conditions. The velocity profile, V(x), and the thickness, delta, of the upflow layer generated below the downward-facing wall in the sedimentation vessel were measured under a microscope with polystyrene latex as a tracer particle. Here, x is the distance from the vessel wall. All the data of the velocity profile are represented by a single curve, [Vmax- V(x)]/Vmax = [(delta -x)/delta]2, irrespective of the volume fraction, H, and tilt angle, theta, in the range of 0.05 < H < 0.30 and 10 degrees < theta < 40 degrees, where Vmax is the maximum velocity found at the upflow boundary. The rate of fall of the top surface of the suspension v(H, theta) fits the function, v(H, theta) = v(0, theta)(1-H)exp[-(aH + bH2)], well, irrespective of H and theta. These experimental results are compared with the theory of Acrivos and Herbolzheimer.

We measured the electric current dependence of sedimentation curves of swine erythrocytes in a saline solution at the volume fraction of erythrocytes H = 0.091 and 0.220. The sedimentation curve fitted well to the exponential type equation l = a[1-exp(-bt)] at the upward initial electric current I0 = 0.50 mA, 1.01 mA and 1.50 mA, where l is the length of the medium layer at time t, and a and b are phenomenological parameters. The initial slope v0 of sedimentation curve was enhanced from 0.68 mm/hr at I0 = 0 mA to 2.85 mm/hr, 3.87 mm/hr and 5.50 mm/hr at I0 = 0.50 mA, 1.01 mA and 1.50 mA, respectively, for H = 0.220. We also made sedimentation measurements of erythrocytes in their own plasma at H = 0.220 and 0.316. Sedimentation curves coincided with the sigmoidal type equation l = l infinity/[1 + (t50/t)beta] at I0 = 0 mA and 0.50 mA, where l infinity is l at t----infinity, t50 is the time when the plasma level falls to l infinity/2 and beta is a constant. The maximum slope vmax of sedimentation curve increased from 13.29 mm/hr at I0 = 0 mA to 18.65 mm/hr at I0 = 0.50 mA for H = 0.220.

In the present paper, the effect of a DC electric field on the swine erythrocytes settling in physiological saline solution in a vertical tube would be investigated. An attempt is made to compare the settling of erythrocytes with and without an electric field, and to present good reproducible data

In order to elucidate the mechanism of erythrocyte sedimentation in plasma, we have measured the concentration distribution of erythrocytes in a sedimentation vessel using a newly developed image analyzing system. As time passes, erythrocyte-poor domains are formed in the suspension column. The total number of domains as well as the size of each domain, was evaluated by a series of analyses, setting up various volume fraction thresholds H r for the domain. The total number of domains initially increases, reaches a maximum just when the interface roughness of the suspension column is maximum, and then decreases gradually. These characteristic behaviors are found in a wide range of H r from 0.03 to 0.46. These results suggest that the sigmoidal erythrocyte sedimentation curve can be explained by an effective upflow of plasma through the erythrocyte-poor domain which is produced by aggregation of erythrocytes. Other previous experimental reports are also discussed on the basis of our results.

In order to clarify the relation between the enhanced erythrocyte sedimentation rate in an inclined vessel and the medium upflow underneath the downward‐facing wall of the vessel, we have measured the upflow velocity V along the vessel length y and the width δ of the upflow layer at tilt angles θ of 10°, 20°, 40°, and 60°. Sample was a swine erythrocyte suspension at nonaggregated state at the volume fraction of 0.2. Polystyrene latex particles with 1‐μm diameter were mixed in the suspension to visualize the motion in the upflow layer. Observations were made with a video system under an invert microscope at room temperature. The upflow layer began to be formed immediately after the sample injection, and reached to the steady state within 10 min, while keeping a thin layer. The time for reaching the steady state decreased with increasing θ. The upflow velocity was much higher by two to three orders of magnitude than the sedimentation rate. Both V and δ increased with increasing θ. The observed velocity pro...

We have measured the velocity profile within the upflow layer in an inclined rectangular vessel during erythrocyte sedimentation with a microscopic video system and estimated the flow rate of the upflow. A good agreement between experimental data and the theory by Acrivos et al. was obtained. The results show that the Boycott effect or the enhanced sedimentation rate is due to the upflow in an inclined vessel.

Erythrocyte sedimentation rate was measured in a physiological saline solution as a function of both the tube diameter d and the initial suspension length iota 0. All the sedimentation curves in the vertical tubes were found to overlap over the range 1 mm less than d less than 7 mm and 100 mm less than iota 0 less than 330 mm, within the precision of 8 %. The sedimentation curves in the tilted tubes fit well to an exponential equation of iota = a [1 - exp (-bt)], where iota and t are the medium length along the tube and the elapsed time from sample injection respectively: At fixed tilt angle theta and iota 0, a was roughly constant and b was roughly proportional to l/d, while at fixed theta and d, a was linearly proportional to iota 0 and b was constant. The initial slope ESR (theta) = (d iota/dt) t----0 = ab was represented by a unique straight line as a function of iota 0/d for each fixed tilt angle. The experimental results were compared with some recent theories.