To what extent does a minimal atherosclerotic plaque alter the arterial wall shear stress distribution? A model study by an electrochemical method

An electrochemical surface shear stress measurement was applied to a model of very thin unilateral arterial stenosis (height of 1/8 of the model pipe diameter with very smooth surface). Three dimensional wall shear stress distribution was measured under steady flow field from a relatively low Reynolds number, Re = 270, to a high Reynolds number, Re = 1200. There was a characteristic high and low wall shear distribution pattern around the stenosis. There were also remarkable high shear stress areas on the opposite wall and both side walls of the stenosis. It was clearly shown that three dimensional structure of the flow field, hence, the wall shear stress distribution, is affected by a minimal change on the arterial wall.     

Evidence for increased hepatic sympathetic nerve activity resulting in hyperglycemia in response to hemorrhage-induced reflex stimulation in anesthetized dogs

To investigate the role of the sympathoadrenal system in glucose mobilization by the liver during hemorrhage, catecholamine (CA) output from both adrenal glands was determined in anesthetized dogs. Venous blood draining from both adrenal glands was combined in a Y-tube that was connected to an electromagnetic flow probe to measure total adrenal venous blood flow. Plasma concentrations of norepinephrine (NE), epinephrine (E), dopamine (DA), and glucose (GL) were determined in various vascular regions. Adrenal CA output (nanograms per minute) under basal conditions was 50.2 +/- 13.6, 181.4 +/- 41.9, and 13.7 +/- 4.8 for NE, E, and DA, respectively. These values were found to increase significantly (P less than 0.05) in response to 5 min of hemorrhage, reaching a maximum output (nanograms per minute) of 663.6 +/- 160.6 (NE), 2503.4 +/- 607.8 (E), and 141.7 +/- 43.7 (DA). Aortic CAs (nanograms per millilitre) increased significantly with a predominant increase in E (0.33 +/- 0.08 to 3.75 +/- 1.03, P less than 0.05). In contrast, increases in portal and hepatic venous CAs (nanograms per millilitre) were characterized by a predominant increase in NE (0.30 +/- 0.06 to 0.64 +/- 0.11 and 0.17 +/- 0.02 to 0.31 +/- 0.07, respectively, P less than 0.05). Hepatic venous and aortic GL concentrations also increased significantly during hemorrhage. Among the various correlations between plasma CA and GL concentrations, the strongest correlation was found between hepatic venous NE and hepatic venous GL (r = 0.804, P less than 0.001). Correlation coefficients obtained with aortic NE and E were weaker but significant (r = 0.603 and r = 0.608, respectively, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Fine structure of wide and narrow vertebrate muscle Z-lines. A proposed model and computer simulation of Z-line architecture

A model of the structure of vertebrate Z-lines and Z-line analogs is introduced and supported by evidence from electron microscope studies of wide Z-lines (rat and feline soleus, and feline and canine cardiac muscles), narrow Z-lines (guppy, newt and frog skeletal muscles), and Z-rods (from a patient with nemaline myopathy and from cardiac muscles of aged dog). The model is based on a pair of Z-filaments (termed a Z-unit), which are linked near their centers at a 90 degrees angle and form bridges between neighboring antipolar thin (actin) filaments. A square lattice of four Z-filament pairs (the basic structure of the Z-line, termed a Z-line unit) defines the geometrical position of the I-square unit. In this native state of the Z-line, small square and large square net forms appear in cross-section. Other cross-sectional patterns of Z-lines, including basket-weave and diagonal-square net patterns, can be explained by detachment of the Z-filament from the Z-filament binding region within each Z-filament pair due to chemical or physical stress. Dissection of Z-lines and Z-line analogs with calcium-activated neutral protease provides evidence that the width of all wide Z-line structures is determined by the amount of overlap of antipolar thin filaments from adjacent sarcomeres. Longitudinal patterns of narrow and wide Z-lines are shown and described in relation to the model. To test the proposed model, the dynamics of the Z-line unit structure were computer-simulated. An attempt was made to correlate longitudinal (z direction) and cross-sectional (x and y directions) patterns and to determine the amount of movement of thin or Z-filaments that is required to explain the diversity observed in cross-sectional patterns of Z-lines. The computer simulations demonstrated that the structural transitions among the small square, and therefore large square net, as well as basket-weave and diagonal-square net forms seen in cross-sections could be caused by movements of thin filaments less than 10 nm in any direction (x, y or z).(ABSTRACT TRUNCATED AT 400 WORDS)     

Properties of the strongly immobilized signal observed in spin-labeled erythrocytes

A strongly immobilized signal from fatty acid spin labels was observed in human erythrocytes treated with oxidizing agents such as glutaraldehyde, hydrogen peroxide, phenylhydrazine and copper-ortho-phenanthroline. This signal was also observed in freshly prepared ghosts treated with potassium superoxide and in old erythrocyte ghosts. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of these samples demonstrated the diffuse, nondiscrete bands of high molecular weight due to the cross-linking of membrane proteins. The temperature and pH dependences of the outer hyperfine splitting of this signal were very similar to those of bovine serum albumin. We propose that the strongly immobilized signal reflects the interaction of the lipids with the cross-linked products of membrane proteins.     

Stimulating effects of insulin and low-density lipoprotein on cell growth and macromolecular syntheses of HeLa cells cultured in K(+)-depleted medium

The influence of the intracellular K+ concentration on the effects of growth factors (insulin, EGF, hydrocortisone, and transferrin) and LDL on growth of HeLa cells was investigated. Upon replacement of K+ in a chemically defined medium (K(+)-CDM) by Rb+ (Rb(+)-CDM), about 80% of the intracellular K+ was replaced by Rb+ within 24 h, but showed no further change in the next 24 h, irrespective of addition of dialyzed calf serum (5%) or growth factors to the medium. In Rb(+)-CDM, cell growth and DNA synthesis were greatly suppressed, although cell viability was not significantly altered for 72 h. The suppression of cell growth was partially restored by addition of serum, insulin (5 micrograms/ml), or LDL (2.5 mg/ml) to Rb(+)-CDM. A combination of serum and insulin or insulin and LDL stimulated cell growth to approximately the level in K(+)-CDM without any addition, but a combination of serum and LDL did not have more effect than that of serum alone. Unexpectedly, other factors were ineffective in stimulating growth in Rb(+)-CDM. In Rb(+)-CDM, the effect of insulin was lost in 24-48 h, whereas that of LDL persisted for at least 96 h. Insulin and LDL also enhanced growth in K(+)-CDM. After cessation of cell growth in Rb(+)-CDM for 24 h, addition of insulin and/or LDL markedly restored cell growth and DNA synthesis. Therefore, insulin and LDL may stimulate certain mechanisms required for cell growth that can operate in K(+)-deficient conditions.     

Induction of {alpha}-Amylase is Repressed by Uniconazole, an Inhibitor of the Biosynthesis of Gibberellin, in a Dwarf Mutant of Rice, Waito-C

A system for induction of synthesis of     

Efficient production of IGG human monoclonal antibodies by lymphocytes stimulated by lipopolysaccharide,pokeweed mitogen,and interleukin 4

Summary Extensive screening of the mitogens lipopolysaccharide (LPS), pokeweed mitogen (PWM), andStaphylococcus aureus Cowan I (SAC I), alone and in combination and with and without interleukin (IL) was performed forin vitro activation of regional lymph node lymphocytes from lung cancer patients for the production of human IgG, IgM, and IgA. As assessed by electrofusion of the lymphocytes following their exposure to these agents with mouse myeloma cells and incubation of the fused hybridoma, a remarkable stimulatory effect was shown by LPS and particularly by LPS plus IL-4, which was substantially greater than that of either SAC I or PWM with or without various IL. Optimization studies indicated that the addition of PWM to LPS and IL-4 in the culture medium further stimulated the human antibody (Ab) production, and that the optimal formulation for stimulations of human IgG production was a culture medium containing 20 μg/ml of LPS, 1/500 of PWM, and 100 u/ml of IL-4.