Menadione-induced cardiotoxicity is associated with alteration in intracellular Ca2+ homeostasis

Cardiotoxicity of menadione was elucidated in neonatal rat cardiomyocytes. When incubated with menadione, contraction of myocytes initially slowed down and eventually stopped. Later blebs appeared on the cell surface, leading to cell degeneration. During the time of diminished cellular contraction, a large portion of endogenous ATP was depleted whilst intracellular Ca2+ levels were increased. However, if menadione was washed out prior to termination of contraction, the myocytes survived and most of the cells resumed regular contraction. Preincubation of the cells with diltiazem (a Ca2+ antagonist), or fura-2 acetoxymethyl ester (a chelate for Ca2+), or antipain (a proteinase inhibitor) suppressed menadione's ability for cellular damage. These results indicate that menadione is toxic to cardiomyocytes, and that the increase of intracellular Ca2+ is related to the mechanism of cardiotoxicity of menadione.

Effect of body iron stores on serum aluminum level in hemodialysis patients

To evaluate the influence of body iron stores on the serum aluminum (Al) level, we studied the correlation between iron status (the serum ferritin, serum iron and transferrin saturation) and serum Al levels in 68 severely anemic hemodialysis patients. Among them, 36 underwent the desferrioxamine (DFO) mobilization test. These 68 patients were divided into three groups according to their serum ferritin level. The basal Al level in the patient group was 41.4 +/- 37.4 micrograms/l (control, 4.1 +/- 2.4 micrograms/l). The serum Al level after DFO infusion of the patient group was 111.1 +/- 86.8 micrograms/l. A significantly higher basal Al and peak Al level after DFO infusion were found in group 1 patients (serum ferritin less than 300 micrograms/l) when compared to group 2 (serum ferritin 300-1,000 micrograms/l) and group 3 (serum ferritin greater than 1,000 micrograms/l) patients. A significant negative correlation between serum ferritin and basal serum Al (r = -0.544, p = 0.0001), as well as peak serum Al after DFO infusion (r = -0.556, p = 0.0001), was noted. Similarly, a negative relationship between serum Al (both basal and peak) and either serum iron or transferrin saturation was noted. However, there was no correlation between the serum Al level and the dosage of aluminum hydroxide. In conclusion, serum ferritin, serum iron and transferrin saturation were inversely correlated with serum Al in our hemodialysis patients. Iron deficiency may probably increase Al accumulation in these patients.

[The relation between ventricular late potential and ventricular arrhythmia in different stages of acute myocardial infarction]

50 cases of acute myocardial infarction (AMI) were examined for ventricular late potential (VLP) six times in total within 4 weeks. At the same time the patients clinical condition was observed. It is found that: (1) In our group the occurrence of VLP in AMI was 28% and VLP was unstable in both acute stage and recovery stage. (2) During acute stage, the difference of positive VLP rate is significant between the ventricular fibrillation group and normal rhythm group (P less than 0.05), but there is no significant difference between the ventricular ectopia group and normal rhythm group. During recovery stage, the difference of positive VLP rate is very significant between the ventricular ectopia and normal rhythm group (P = 0.001). As there was only 1 case of ventricular fibrillation occurring in the recovery stage, no comparison could be made. (3) There is no correlation between VLP and clinical conditions, such as age sex, location of the infarction, existence of old infarction and LVEF. However, the difference of the peak serum CPK level is significant between VLP positive and negative group (P less than 0.05).

Cultured Ovules as Models for Cotton Fiber Development under Low Temperatures

Cotton fibers (Gossypium hirsutum L.) developing in vitro responded to cyclic temperature change similarly to those of field-grown plants under diumal temperature fluctuations. Absolute temperatures and rates of temperature change were similar under both conditions. In vitro fibers exhibited a "growth ring" for each time the temperature cycled to 22 or 15 degrees C. Rings were rarely detected when the low point was 28 degrees C. The rings seemed to correspond to alternating regions of high and low cellulose accumulation. Fibers developed in vitro under 34 degrees C/22 degrees C cycling developed similarly to constant 34 degrees C controls, but 34 degrees C/22 degrees C and 34 degrees C/15 degrees C cycling caused delayed onset and prolonged periods of elongation and secondary wall thickening. Control fiber length and weight were finally achieved under 34 degrees C/22 degrees C cycling, but both parameters were reduced at the end of the experiment under 34 degrees C/15 degrees C cycling. Fibers developed under all conditions had equal bundle tensile strength. These results demonstrate that: (a) cool temperature effects on fiber development are at least partly fiber/ovule-specific events; they do not depend on whole-plant physiology; and (b) cultured ovules are valid models for research on the regulation of the field cool temperature response.

Phase measurement for surface infrared-visible sum-frequency generation

We present what are to our knowledge the first measurements of the phase of the infrared-visible sum-frequency generation signal. We introduce two techniques and apply the measurements to the determination of the polar orientation of a selected group of atoms within an adsorbed molecule.

Effect of ethanol intake on rat liver mitochondrial respiration and oxidative phosphorylation

The effect of ethanol intake on liver mitochondrial functions was investigated by feeding rats with a liquid isocaloric diet containing various concentrations of ethanol. We found that after feeding the liquid diet for 2 to 3 months, the body weight of rats did not show a significant difference between treated and control groups. However, the mitochondrial respiration rate decreased significantly with the increase of ethanol concentration in the diet. We found that when the rats were fed on 10.8% ethanol, the average succinate-supported State 3 respiration rate decreased from 54.5 to 44.8 nmol O2/min/mg and the glutamate-malate-supported State 3 respiration rate decreased from 38.8 to 23.6 nmol O2/min/mg as compared with the control. Interestingly, we noted that ethanol intake caused a more drastic effect on State 3 respiration than on State 4 respiration, irrespective of the substrate utilized by the mitochondria. In addition, the respiratory control and ADP/O ratios were found to decrease concomitantly with the increase of ethanol level in the diet. Moreover, we found that the effect of ethanol on both respiratory control and ADP/O ratios of liver mitochondria was more pronounced in glutamate-malate-supported respiration than succinate-supported respiration. These results clearly demonstrate that ethanol intake by the rat can cause impairment of liver mitochondrial respiration and oxidative phosphorylation, and that these effects are exerted through damage to mitochondrial membranes.

[Studies on the antiarrhythmic effects of leaves of Dendropanax chevalieri (Vig.) Merr. et Chun]

Aqueous extract of the leaves of Dendropanax chevalieri (DC), administrated orally, showed prominent protective effect against arrhythmias induced by iv aconitine CaCl2 (120mg/kg) in mice and BaCl2 (4mg/kg) in rats. In anesthetized rabbits, the duration of arrhythmia elicited by ivAdr 75 micrograms/kg was markedly shortened by iv DC 0.4g/kg. It might also obviously delay the onset of arrhythmias and cardiac electricity disappearance evoked by ouabain perfusing consistently into isolated guinea-pig hearts.

[Evaluation of 3 chest leads CM5, CC5, and CL5 and factors which influence the results]

In recent few years, many authors had discussed the possibilities of using bipolar precordial leads to replace lead V5 in diagnosing anterior wall myocardial ischemia. But there still remains some problems to be solved: (1) Are there any difference between bipolar precordial leads and lead V5 in wave forms? (2) What kind of factors influence the ST deviation? 36 patients were studied by comparing unipolar lead V5 with respect to three different bipolar chest leads CM5, CC5, CL5 both in lying and sitting positions. We found that: (1) The differences is least significant between bipolar CC5 and lead V5 while it is most significant between bipolar lead CM5 and lead V5. (2) The deviation of ST segment in bipolar leads is affected both by potential at negative electrode as well as potential at positive electrode. Statistical analysis revealed that ST segment is positively related to the potential on positive electrode and negatively related to the potential on negative electrode. For this reason, therefore, in the view point of most comparable ST deviation with lead V5 for monitoring of myocardial ischemia, it is advisable to locate the negative electrode at the site on chest with least potential. Usually we place the negative electrode on V6R to compose a bipolar lead CC5.

Nonlinear optical properties of potential sensitive styryl dyes

The nonlinear optical properties of dyes that alter their optical characteristics rapidly with membrane potential are described. The second harmonic signals from these dyes characterized in this paper are among the largest that have been detected to date. Structural conclusions are drawn from the second harmonic signals generated by the Langmuir Blodgett monolayers used in these measurements. Our results indicate that with appropriate instrumentation second harmonic signals could readily be detected from living cells stained with these dyes.

Biological mimicry of antigenic stimulation: analysis of the in vivo antibody responses induced by monoclonal anti-idiotypic antibodies

In this study, the induction of protective antibodies against a bacterial pathogen in mice was used as a model for idiotype vaccine development. The antibody responses induced in different strains of mice by the hapten phosphorylcholine (PC) coupled to ovalbumin, PC-OVA, were compared with the responses induced by carrier conjugates of two different anti-idiotopic antibodies. One anti-idiotope, 4C11, exhibits the characteristics of an internal image of phosphorylcholine, and therefore is classified as an Ab2 beta; the other, F6, does not mimic antigen, and therefore is classified as an Ab2 alpha. The analysis of the temporal kinetics of the IgM and IgG1 anti-PC responses induced by nominal and idiotope antigens revealed dynamic responses characterized by changes in the quality and quantity of the antibody populations during the course of the immune response. All three antigens could stimulate antibodies that were PC-specific and T15 idiotope-positive in BALB/c and A/St mice. The highest titre of T15+ anti-PC antibodies was achieved with an immunization protocol which involved priming with Ab2 alpha followed by challenge with PC-OVA. Antibodies specific for the extended hapten, diazophenylphosphorylcholine, and hapten-carrier bridge determinants were being stimulated late in the responses to PC-OVA. BALB-c, A/St and CBA/N (Xid) mice all produced, late in the response to Ab2 alpha, high T15+ antibody titres which do not bind PC. The induction of T15+, non-PC binding, antibody suggests that T15 is a regulatory idiotope, expressed on antibodies having differing antigenic specificities. With regard to vaccine development, these results support the contention that effective induction of antibodies does not depend on stimulating a unique idiotope but can be achieved by anti-idiotypes reacting with different idiotopes. In addition, these results suggest that the combined use of idiotope and nominal antigens in an immunization protocol may provide the maximal protective immunity.

Extended X-ray absorption fine structure of Mn2+ and Mn2+ X ATP complex bound to coupling factor 1 of the H+-ATPase from chloroplasts

The spinach chloroplast ATPase, coupling factor 1, contains three tight Mn2+-binding sites which interact cooperatively. The bound manganese coordinations were studied by x-ray absorption fine structure analysis. Mn2+ was found to be bound to the enzyme with an average Mn-O bond length of 2.15 +/- 0.15 A, significantly shorter than the 2.15 +/- 0.15 A of the Mn-O bond of the average first hydration shell for Mn2+ in aqueous solution. On adding ATP to the manganese-enzyme mixture, a tertiary complex of Mn2+ X ATP X enzyme was formed as indicated by the appearance of a second shell. Mn-P bond distances were estimated at 4.95 +/- 0.15 A in the tertiary Mn2+ X ATP X enzyme complex, which was considerably longer than the Mn-P bond distance of 3.36 +/- 0.15 A for the Mn2+ X ATP complex in aqueous solution. The Mn-P bond distance in the tertiary Mn2+ X ATP X enzyme complex decreased to 4.32 +/- 0.15 A when selenite, a potent effector of ATPase activity, was added. Based on these results, it is suggested that the tertiary complex is required for catalysis. The stimulation of ATP hydrolysis by anions such as selenite may be the result of shortening the distance between Mn2+ and the ATP phosphates in the enzyme active site.

Hormonal regulation of extracellular plasminogen activators and Mr approximately 54,000 plasminogen activator inhibitor in human neoplastic cell lines, studied with monoclonal antibodies

We have studied the regulation by glucocorticoids and dibutyryl cAMP of the amounts of urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and a Mr approximately 54000 plasminogen activator inhibitor accumulated in serum-free conditioned culture fluid by a human fibrosarcoma, a human glioblastoma and a human melanoma cell line (HT-1080, UCT/gl-1 and Bowes). For the quantitation of u-PA and t-PA, we used sandwich-type ELISA with a combination of polyclonal and monoclonal antibodies. For an estimation of variations in the amount of the inhibitor, we used sodium dodecyl sulphate-polyacrylamide gel electrophoresis followed by Coomassie blue staining of conditioned culture fluid proteins, the inhibitor protein band being identified by its selective removal by passage of the conditioned culture fluids through a column with monoclonal antibodies against the inhibitor. The modulation of the 3 proteins by the hormonal agents varied greatly between the cell lines. The proteins were independently regulated, in the sense that the hormonal agents did not concomitantly change their levels in the direction expected either to increase or decrease total extracellular plasminogen activator activity. In conditioned culture fluids containing both t-PA and inhibitor, the two were present in the medium as a Mr approximately 120 000 complex. In contrast, no u-PA inhibitor complexes were found in conditioned culture fluid from any of the cell lines; this is likely to be due to the occurrence of u-PA in the culture fluid in the one-chain proenzyme form, which, unlike active u-PA, does not react with the inhibitor. These findings illustrate the complexity of the regulation of extracellular plasminogen activator activity, and imply that the presumed functional diversity of u-PA and t-PA may be related to their independent regulation.

Monoclonal antibodies to human 54,000 molecular weight plasminogen activator inhibitor from fibrosarcoma cells--inhibitor neutralization and one-step affinity purification

Mouse monoclonal antibodies were derived against a plasminogen activator inhibitor with a mol. wt. of approximately 54,000 (54 K) from the human fibrosarcoma cell line HT-1080. Screening for hybrids producing antibodies directed against the inhibitor was performed with enzyme-linked immunosorbent assay and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting. Four clones of hybridomas producing IgG1 antibodies were further characterized. The inhibitor was purified approximately 50-fold to homogeneity from conditioned cell culture fluid with a yield of approximately 85% by a one-step procedure using Sepharose-conjugated monoclonal antibody. In the 125I-fibrin plate assay one of the antibodies neutralized the effect of the inhibitor on urokinase-type plasminogen activator. Two of the antibodies bound complexes between urokinase-type plasminogen activator and inhibitor while the remaining two antibodies did not. The antibodies could be used for immunocytochemical localization of the inhibitor in HT-1080 cells. All four antibodies cross-reacted with a plasminogen activator inhibitor derived from cultured human umbilical cord endothelial cells.

General detection of proteins after electroblotting by trinitrobenzene sulphonic acid derivatization and immunochemical staining with a monoclonal antibody against the trinitrophenyl group

A sensitive method for the general detection of proteins electroblotted onto nitrocellulose sheets after separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis is described. The proteins on the blots were reacted with 2,4,6-trinitrobenzene sulphonic acid. The resulting trinitrophenyl groups on the proteins were rendered visible by immunochemical staining with a monoclonal anti-trinitrophenyl antibody, and a peroxidase-conjugated second antibody. Using various proteins, the method was compared to the amidoblack method for staining of protein blots. The method was 10-100-fold more sensitive than the amidoblack method. Amounts as low as 1 ng of human serum albumin could be detected.

Linear phase shift electrodes for the planar electrooptic prism deflector

Three types of compensation electrode are analyzed, which give a more linear phase shift to the propagating optical beam for the planar electrooptic prism deflector. For Types I and III, the more linear phase shift is achieved by varying the slope of the central tilt electrode at the edge regions. For Type II, the more linear phase shift is achieved by cascading an electrode, giving an opposite phase shift to the conventional electrode at the edge regions. Theoretically, Type III is expected to perform best. A physical device was made with Type III electrodes in an array, and it has shown significant improvement in sidelobe suppression and beam size conservation.