The effect of sodium fluoride on the adenine nucleotide pool in erythrocytes of Wistar rats

The effect of sodium fluoride on the content of adenine nucleotides, adenine nucleotide pool and energy potential of erythrocytes was studied in male Wistar rats, depending on the dose and time of exposure. Sodium fluoride was administered for 4 and 8 weeks at 4 or 16 ppm through a gastric tube. The concentration of fluorine in serum, ATP, ADP and AMP content in blood and erythrocytes, adenine nucleotide pool and energy potential of erythrocytes were calculated. The results were expressed in SI units and compared statistically with Student's t-test (Statgraphics v. 5.0 software). A significant reduction in the content of ATP and ADP and an increase in the content of AMP in erythrocytes was found after 4 weeks of exposure to 4 or 16 ppm NaF. The adenine nucleotide pool and energy potential were reduced with the smaller dose. After 8 weeks, the ADP content remained significantly reduced with the smaller dose, while the greater dose was associated with a higher energy potential of the cells. Correlations between serum concentration of fluorine, content of adenine nucleotides and adenine nucleotide pool in erythrocytes were noted in all study groups.

The effect of systemic hypoxia on interstitial and blood adenosine, AMP, ADP and ATP in dog skeletal muscle

1. We investigated the effect of moderate systemic hypoxia on the arterial, venous and interstitial concentration of adenosine and adenine nucleotides in the neurally and vascularly isolated, constant-flow perfused gracilis muscles of anaesthetized dogs. 2. Systemic hypoxia reduced arterial PO2 from 129 to 28 mmHg, venous PO2 from 63 to 23 mmHg, arterial pH from 7.43 to 7.36 and venous pH from 7.38 to 7.32. Neither arterial nor venous PCO2 were changed. Arterial perfusion pressure remained at 109 +/- 8 mmHg for the first 5 min of hypoxia, then increased to 131 +/- 11 mmHg by 9 min, and then decreased again throughout the rest of the hypoxic period. 3. Arterial adenosine (427 +/- 98 nM) did not change during hypoxia, but venous adenosine increased from 350 +/- 52 to 518 +/- 107 nM. Interstitial adenosine concentration did not increase (339 +/- 154 nM in normoxia and 262 +/- 97 nM in hypoxia). Neither arterial nor venous nor interstitial concentrations of adenine nucleotides changed significantly in hypoxia. 4. Interstitial adenosine, AMP, ADP and ATP increased from 194 +/- 40, 351 +/- 19, 52 +/- 7 and 113 +/- 36 to 764 +/- 140, 793 +/- 119, 403 +/- 67 and 574 +/- 122 nM, respectively, during 2 Hz muscle contractions. 5. Adenosine, AMP, ADP and ATP infused into the arterial blood did not elevate the interstitial concentration until the arterial concentration exceeded 10 microM. 6. We conclude that the increased adenosine in skeletal muscle during systemic hypoxia is formed by the vascular tissue or the blood cells, and that adenosine is formed intracellularly by these tissues. On the other hand, adenosine formation takes place extracellularly in the interstitial space during muscle contractions.

Inhibition by combined therapy with ticlopidine and aspirin of enhanced platelet aggregation during physical exercise in patients with coronary artery disease

BACKGROUND

Strenuous exercise can be a major trigger for coronary thrombosis and it enhances platelet aggregation.

METHODS

We evaluated the effect of antiplatelet therapy on shear stress-induced platelet aggregation (SIPA), in addition to agonist-induced aggregation, before and immediately after ergometer exercise in patients with stable coronary artery diseases (CAD). Forty-eight patients with stable CAD were randomly distributed into 3 groups: no antiplatelet drug (patient control, n = 16), aspirin (ASA) monotherapy (n = 16), and combined therapy with ticlopidine (TIC) and ASA (n = 16).

RESULTS

There were significant increases in not only adenosine phosphate (ADP)- and collagen-induced platelet aggregation but also in SIPA during exercise by the patient control group. ASA monotherapy did not attenuate the enhanced ADP-induced aggregation nor SIPA. Combined ASA + TIC therapy significantly inhibited SIPA as well as ADP-induced aggregation both before and after exercise. Significant increases in levels of plasma von Willebrand factor (vWF) occurred during exercise, and these antiplatelet therapies had no apparent effect on increased vWF levels during exercise. Exercise induced a significant increase in the plasma thrombin-antithrombin III complex level with no significant changes in the level of plasmin-plasmin inhibitor complex level in all 3 groups.

CONCLUSIONS

Combined therapy with ASA + TIC effectively inhibited increased platelet aggregability in response to acute exercise, with no effects on coagulant or fibrinolytic potentials in patients with CAD. The data suggest that TIC combined with ASA may be superior to ASA alone in preventing acute coronary events during exercise in patients with coronary atherosclerotic disease.

Determination, activity and biological role of adenylosuccinate lyase in blood cells

Adenylosuccinate lyase deficiency, which is associated with severe mental retardation and autistic features, was discovered in 1984. Since then this enzyme has been analyzed in many human tissues and it is now generally agreed that screening for this enzyme defect should be performed in all unexplained neurological diseases. The aim of the present study was to analyze adenylosuccinate lyase activity in blood cells by a fast simple method adaptable to screening purposes. The activity was also analyzed in B-lymphocytes from patients with B-cell chronic lymphocytic leukemia. The biological role of adenylosuccinate lyase and its importance in regulating cellular levels of AMP is discussed.

The effect of resveratrol on the platelet secretory process induced by endotoxin and thrombin

The effect of resveratrol (trans-3,4',5-trihydroxystilbene) on the release of adenine nucleotides and proteins from blood platelets activated by lipopolysaccharide (LPS), from Proteus mirabilis and by thrombin, were studied. Thrombin stimulated the release of adenine nucleotides from dense granules and proteins from alpha-granules. The LPS (0.3 microg/10(8) platelets, 5 min, 37 degrees C), like thrombin (2.5 U/10(8) platelets, 5 min, 37 degrees C) was found to cause a release of adenine nucleotides and proteins (p <0.05). Resveratrol (6.25-100 microg/ml, 30 min, 37 degrees C) had a different effect on the platelet release reaction caused by either LPS or thrombin. The results indicated that resveratrol inhibited, in dose-dependent manner, the secretory process (release of adenine nucleotides and proteins) induced by thrombin (p <0.05), but it significantly stimulated the liberation of proteins from blood platelets activated by LPS (p <0.05).

Overproduction of antiplatelet antibody against glycoprotein IIb after splenectomy in a patient with Evans syndrome resulting in acquired thrombasthenia

We treated a 33-year-old female with Evans syndrome. She received high dose gamma globulin, prednisolone, and azathioprine, and her platelet count transiently increased. After splenectomy, the platelet count markedly increased. However, the bleeding tendency worsened and the bleeding time was prolonged. A platelet defect, characteristic of thrombasthenia, was found. Antigen-captured ELISA and Western blotting revealed that the patient's serum had an IgG autoantibody against platelet membrane glycoprotein IIb and the patient's plasma inhibited normal platelet aggregation. These findings suggest that overproduction of the antiplatelet antibody is triggered by platelet recovery due to splenectomy and affects platelet function resulting in acquired thrombasthenia.

Accelerated degradation of adenine nucleotide in erythrocytes of patients with chronic renal failure

Recently, we have shown that erythrocytes obtained from patients with chronic renal failure (CRF) exhibited an increased rate of ATP formation from adenine as a substrate. Thus, we concluded that this process was in part responsible for the increase of adenine nucleotide concentration in uremic erythrocytes. There cannot be excluded however, that a decreased rate of adenylate degradation is an additional mechanism responsible for the elevated ATP concentration. To test this hypothesis, in this paper we compared the rate of adenine nucleotide breakdown in the erythrocytes obtained from patients with CRF and from healthy subjects. Using HPLC technique, we evaluated: (1) hypoxanthine production by uremic RBC incubated in incubation medium: (a) pH 7.4 containing 1.2 mM phosphate (which mimics physiological conditions) and (b) pH 7.1 containing 2.4 mM phosphate (which mimics uremic conditions); (2) adenine nucleotide degradation (IMP, inosine, adenosine, hypoxanthine production) by uremic RBC incubated in the presence of iodoacetate (glycolysis inhibitor) and EHNA (adenosine deaminase inhibitor). The erythrocytes of healthy volunteers served as control. The obtained results indicate that adenine nucleotide catabolism measured as a hypoxanthine formation was much faster in erythrocytes of patients with CRF than in the cells of healthy subjects. This phenomenon was observed both in the erythrocytes incubated at pH 7.4 in the medium containing 1.2 mM inorganic phosphate and in the medium which mimics hyperphosphatemia (2.4 mM) and metabolic acidosis (pH 7.1). The experiments with EHNA indicated that adenine nucleotide degradation proceeded via AMP-IMP-Inosine-Hypoxanthine pathway in erythrocytes of both patients with CRF and healthy subjects. Iodoacetate caused a several fold stimulation of adenylate breakdown. Under these conditions: (a) the rate of AMP catabolites (IMP + inosine + adenosine + hypoxanthine) formation was substantially higher in the erythrocytes from patients with CRF; (b) in erythrocytes of healthy subjects degradation of AMP proceeded via IMP and via adenosine essentially at the same rate; (c) in erythrocytes of patients with CRF the rate of AMP degradation via IMP was about 2 fold greater than via adenosine. The results presented in this paper suggest that adenine nucleotide degradation is markedly accelerated in erythrocytes of patients with CRF.

New sample preparation method for the capillary electrophoretic determination of adenylate energy charge in human erythrocytes

The first step in the separation of adenine nucleotides from different types of tissues or cells is deproteinization. Several sample preparation methods successfully used for a number of tissues or cells failed to work with erythrocytes. Use of strong acids or bases for deproteinization resulted in a low yield due to the hydrolysis of adenine nucleotides. Moreover, the neutralization of these acids or bases increased the ionic strength, resulting in broad and overlapping peaks. In neutral salt precipitation methods, saturated salts caused clogging of the capillaries. A new deproteinization procedure method was developed. The samples were deproteinized by heating of erythrocytes in boiling distilled water at 95 degrees C for 5 min. The denatured proteins were removed by centrifugation and membrane filtration. The adenine nucleotides were then separated using a polyacrylamide coated capillary. Depending on the type, diameter, length of the capillary and the voltage applied, an average of 16.50 min was sufficient for the separation of adenine nucleotides. All adenine nucleotides were clearly resolved and gave very sharp peaks. The amount of each adenine nucleotide was calculated from the areas under the peaks and AEC values were calculated using the integrator software. The AEC value of 0.91+/-0.04 (n=10) obtained for healthy persons was in good agreement with the literature value of 0.85-0.95. These reported method for sample preparation and capillary electrophoresis is simple, fast and inexpensive compared to the previously reported sample preparation, HPLC and enzymatic methods for the determination of AEC.

A 37 kDa 2-5A binding protein as a potential biochemical marker for chronic fatigue syndrome

PURPOSE

Recent studies have revealed abnormalities in the ribonuclease L pathway in peripheral blood mononuclear cells of patients with the chronic fatigue syndrome. We conducted a blinded study to detect possible differences in the distribution of 2-5A binding proteins in the cells of patients with chronic fatigue syndrome and controls.

PATIENTS AND METHODS

We studied 57 patients with chronic fatigue syndrome and 53 control subjects (28 healthy subjects and 25 patients with depression or fibromyalgia). A radioactive probe was used to label 2-5A binding proteins in unfractionated peripheral blood mononuclear cell extracts and to compare their distribution in the three groups.

RESULTS

A 37 kDa 2-5A binding polypeptide was found in 50 (88%) of the 57 patients with chronic fatigue syndrome compared with 15 (28%) of the 53 controls (P < 0.01). When present, the amount of 37 kDa protein was very low in the control groups. When expressed as the ratio of the 37 kDa protein to the 80 kDa protein, 41 (72%) of the 57 patients with chronic fatigue syndrome had a ratio > 0.05, compared with 3 (11%) of the 28 healthy subjects and none of the patients with fibromyalgia or depression.

CONCLUSION

The presence of a 37 kDa 2-5A binding protein in extracts of peripheral blood mononuclear cells may distinguish patients with chronic fatigue syndrome from healthy subjects and those suffering from other diseases.

Energy metabolism and lipid peroxidation of human erythrocytes as a function of increased oxidative stress

To study the influence of oxidative stress on energy metabolism and lipid peroxidation in erythrocytes, cells were incubated with increasing concentrations (0.5-10 mM) of hydrogen peroxide for 1 h at 37 degrees C and the main substances of energy metabolism (ATP, AMP, GTP and IMP) and one index of lipid peroxidation (malondialdehyde) were determined by HPLC on cell extracts. Using the same incubation conditions, the activity of AMP-deaminase was also determined. Under nonhaemolysing conditions (at up to 4 mM H2O2), oxidative stress produced, starting from 1 mM H2O2, progressive ATP depletion and a net decrease in the intracellular sum of adenine nucleotides (ATP + ADP + AMP), which were not paralleled by AMP formation. Concomitantly, the IMP level increased by up to 20-fold with respect to the value determined in control erythrocytes, when cells were challenged with the highest nonhaemolysing H2O2 concentration (4 mM). Efflux of inosine, hypoxanthine, xanthine and uric acid towards the extracellular medium was observed. The metabolic imbalance of erythrocytes following oxidative stress was due to a dramatic and unexpected activation of AMP-deaminase (a twofold increase of activity with respect to controls) that was already evident at the lowest dose of H2O2 used; this enzymatic activity increased with increasing H2O2 in the medium, and reached its maximum at 4 mM H2O2-treated erythrocytes (10-fold higher activity than controls). Generation of malondialdehyde was strictly related to the dose of H2O2, being detectable at the lowest H2O2 concentration and increasing without appreciable haemolysis up to 4 mM H2O2. Besides demonstrating a close relationship between lipid peroxidation and haemolysis, these data suggest that glycolytic enzymes are moderately affected by oxygen radical action and strongly indicate, in the change of AMP-deaminase activity, a highly sensitive enzymatic site responsible for a profound modification of erythrocyte energy metabolism during oxidative stress.

Adenine nucleotide synthesis in human erythrocytes depends on the mode of supplementation of cell suspension with adenosine

In suspensions of washed human erythrocytes, adenosine added in a single dose to concentrations of 0.1-10.0 mmol/l suspension was deaminated at rates ranging from 10 to 50 mmol/l cells h. The sum of adenosine, inosine, and hypoxanthine concentrations in the suspension, as well as the intracellular concentration of ATP, remained constant. In the presence of 25-50 mmol/l orthophosphate, addition of a single dose of adenosine into erythrocyte suspension increased the ATP concentration by up to 280% of the initial level. If the initial adenosine concentrations were greater than 5 mmol/l suspension, ATP increased independently of adenosine concentration to the level determined only by the concentration of orthophosphate. After orthophosphate was returned to its initial level, ATP in erythrocytes began to decrease. In the presence of coformycin, erythrocytes utilised adenosine at a rate of 0.2-0.3 mmol/l cells h. Their adenylate pool increased at a rate of 0.10-0.16 mmol/l cells h for several hours, but intracellular ATP increased only slightly. The energy charge of cells decreased significantly from 0.86 +/- 0.05 (control) to 0.82 +/- 0.06. Adenosine continuously pumped into erythrocyte suspensions at rates of 0.02-5.0 mmol/l cells h for several hours caused the adenylate pool of erythrocytes and intracellular ATP to increase synchronously at a rate of 0.02-0.35 mmol/l cells h. The energy charge of these erythrocytes increased significantly up to 0.91 +/- 0.03. After pumping of adenosine was stopped, the intracellular ATP and the adenylate pool began to decrease, returning sometimes to the initial level in 2-3 h.

Hypotension induced by exercise is associated with enhanced release of adenyl purines from aged rat artery

To determine whether the antihypertensive effects of exercise are associated with release of ATP and its metabolites from arteries, we assayed blood pressure and the release of adenine nucleotides and nucleosides from the caudal arteries of exercised and sedentary aged hypercholesterolemic rats. Exercise on a treadmill for 12 wk significantly decreased the rise in systolic and diastolic blood pressure by 7.5 and 15.9%, respectively, with advanced age. The concentrations of oleic, linoleic, and linolenic acids in the caudal artery decreased significantly with exercise, demonstrating an association between exercise and the unsaturation index of caudal arterial fatty acids. The amounts of total adenyl purines released by the arterial segments from exercised rats, both spontaneously and in response to norepinephrine, were significantly greater by 80.0 and 60.7%, respectively, than those released by tissues from sedentary rats. These results suggest that exercise alters the membrane fatty acid composition in aged rats as well as the release of ATP from vascular endothelial cells and that these factors are associated with the regression of the rise in blood pressure normally observed with advanced age.

The biostimulatory effect of red laser irradiation on pig blood platelet function

The molecular mechanisms of laser-induced changes in the cell structure and function are not well known. The authors examined the effects of low-power laser irradiation on unnucleated pig blood platelets. The obtained results showed that laser irradiation (1-5 J) caused in blood platelets lipid peroxidation (measured as thiobarbituric acid reactive substances) and superoxide anion generation, concomitant with the release of adenine nucleotides and proteins from platelets. The maximum platelet response to laser irradiation was observed when doses of 1.8-2 J were used. Our results indicate that red laser irradiation induces: (1) platelet secretory process and the release of substances stored in the specific granules (adenine nucleotides, proteins); and (2) lipid peroxidation partly due to stimulation of endogenous arachidonate and production of its metabolites reacting with thiobarbituric acid.

Protective role of nitric oxide in ischemia and reperfusion injury of the liver

BACKGROUND

The suppressed production of nitric oxide (NO), associated with endothelial dysfunction, is thought to be a cause of ischemia and reperfusion injury of the liver. But findings of the salutary effects of NO enhancement on such injury have been conflicting. In this study, we tested our hypothesis that NO enhancement would attenuate ischemic liver injury. For this purpose, an NO precursor, L-arginine, and a novel NO donor, FK409, were applied to a 2-hour total hepatic vascular exclusion model in dogs.

STUDY DESIGN

L-arginine was administered IV at a dose of 100 mg/kg twice (n = 5), while 300 mg/kg twice of FK409 was infused continuously into the portal vein (n = 5). The drugs were given to the animals for 30 and 60 minutes before and after ischemia, respectively. Non-treated animals were used as the control (n = 10). Two-week survival, systemic and hepatic hemodynamics indices, liver function tests, energy metabolism, and histopathology were analyzed.

RESULTS

Both treatments comparably augmented hepatic tissue blood flow, decreased liver enzyme release, and increased high-energy phosphate restoration during the reperfusion period, all of which contributed to rescuing all of the treated animals from the 2-hour total hepatic ischemia. In contrast, ischemia caused 70% mortality in the control group. Histologically, structural abnormality and neutrophil infiltration were markedly attenuated by the treatments. Systemic hypotension was observed in the animals treated with FK409, however.

CONCLUSIONS

Our data demonstrate that NO enhancement alleviates the liver injury caused by ischemia and reperfusion. The supplementation of L-arginine, rather than FK409, is considered more applicable to clinical use because of the absence of systemic adverse effects.

Effect of ouabain on the breakdown of adenine nucleotides in glucose-depleted nucleated red blood cells. Characterization of ATPase

The present report confirms the presence of Na(+)-K(+)-Mg2+ ATPase in the erythrocyte membranes of the frog Rana balcanica (previously Rana ridibunda) (Schneider et al. 1993; Sofianidou et al. 1994). The Na(+)-K(+)-Mg2+ ATPase activity was 60% reduced by the presence of ouabain. The pH optimum was 8.0, the optimum Mg2+:ATP concentration ratio was 2.2:1. The existence of an ATPase with a high K(m) for ATP (1.48 mmol/l) was postulated. At pH 7.4 and 8.0, the adenine nucleotide pattern of glucose-depleted erythrocytes showed a characteristic reduction in ATP contents. Adenine nucleotide concentrations were higher at pH 7.4 than at pH 8.0. Ouabain inhibited ATP breakdown at both pH values studied. The strongest inhibition was observed at pH 7.4. The decline of the total contents of adenine nucleotides appears to be determined by the rate of AMP breakdown.

Relationship between cladribine (CdA) plasma, intracellular CdA-5'-triphosphate (CdATP) concentration, deoxycytidine kinase (dCK), and chemotherapeutic activity in chronic lymphocytic leukemia (CLL)

Seventeen patients with CLL were treated with oral 2-chloro-2'-deoxyadenosine (cladribine, CdA, 10 mg/m2) on 3 consecutive days and the pharmacokinetic parameters of CdA in patient plasma and its intracellular nucleotides (CdAMP, CdATP) in circulating leukemic cells were studied after the last dose intake and up to 72 h thereafter. The median terminal half life (t1/2) of CdA in plasma was 21.1 h and the area under the curve (AUC) was median 1.2 microMh. The median t1/2 was 14.6 h for CdAMP and 9.7 h for CdATP. The AUC of CdATP in leukemic cells is lower than the AUC of CdAMP (median ratio 0.60). There was no correlation between cellular CdATP and plasma CdA concentrations or dCK activity. The clinical response was related to higher Cmax values for plasma CdA (p = 0.05) and higher products of dCK activity and CdA Cmax of plasma (p = 0.02). The activity of dCK alone was not related to the clinical outcome in this patient group. The results suggest that further steps in the mechanism of action of CdA beyond its bioactivation may be more important, e.g. the extent of DNA fragmentation or the ability of the leukemic cell to go into apoptosis, than the concentration of CdA nucleotides alone.

[The working conditions and health status of workers engaged in the manufacture of pyromellitic dianhydride]

Workers contacting with chemicals (pseudocoumole, durole, dioxane-1,4,pyromellitic dianhydride, etc.) underwent biochemical studies which showed that the blood levels of adenosine triphosphoric acid, potassium, magnesium, calcium were decreased in the workers, but those of adenosine diphosphoric acid, adenosine monophoric acid, sodium, phosphorus and other agents were increased.

Microsphere-induced bronchial artery vasodilation: role of adenosine, prostacyclin, and nitric oxide

We previously found that injection of 15-micron microspheres into the bronchial artery of sheep decreased bronchial artery resistance. This effect was inhibited partially by indomethacin or 8-phenyltheophylline, suggesting that microspheres caused release of a dilating prostaglandin and adenosine. To identify the prostaglandin and confirm adenosine release, we perfused the bronchial artery in anesthetized sheep. In 12 sheep, bronchial artery blood samples were obtained before and after the infusion of 1 x 10(6) microspheres or microsphere diluent into the bronchial artery. Microspheres, but not diluent, decreased bronchial artery resistance by 40% and increased bronchial artery plasma 6-ketoprostaglandin F1 alpha (194.7 +/- 45.0 to 496.5 +/- 101.3 pg/ml), the stable metabolite of prostacyclin, and prostaglandin (PG) F2 alpha (28.1 +/- 4.4 to 46.2 +/- 9.7 pg/ml). There were no changes in PGD2, PGE2, thromboxane B2, adenosine, inosine, or hypoxanthine. Pretreatment with dipyridamole, an adenosine uptake inhibitor, did not affect bronchial artery nucleoside concentrations (n = 7). Microsphere-induced vasodilation was not enhanced by dipyridamole (n = 9) and was not inhibited by either the adenosine receptor antagonist xanthine amine congener (n = 4) or the nitric oxide (NO) synthase inhibitor NG-monomethyl-L-arginine (n = 8). These results do not support a role for either adenosine or NO and suggest that microspheres caused bronchial artery vasodilation through release of prostacylin and an unidentified vasodilator.

Antihypertensive effect of all-cis-5,8,11,14,17-icosapentaenoate of aged rats is associated with an increase in the release of ATP from the caudal artery

Fish oils have been shown to lower blood pressure in hypertensive subjects. All-cis-5,8,11,14,17-icosapentaenoate (EPA), one of the omega-3 polyunsaturated fatty acids, is known to be one of the major active components in fish oil that has beneficial effects on the cardiovascular system. However, little is known about the antihypertensive effect of EPA alone on blood pressure. In the present study, we have determined the spontaneous and noradrenaline-evoked release of ATP, ADP, AMP, and adenosine from caudal arteries of aged (100 weeks old) Wistar rats which were fed a standard diet or a high cholesterol diet, treated with EPA. Dietary EPA administration increased plasma and caudal arterial EPA concentrations and repressed increases in blood pressure with advancing age in both aged rats with and without hypercholesterolemia. In addition, noradrenaline (1 micromol/l) evoked a significantly greater release of purines from the caudal arteries of EPA-administered aged rats compared to both sets of control rats. Regression analysis revealed a significant relationship between the total amount of purines released from the artery and blood pressure. These results suggest that administration of EPA to aged rats increases the release of ATP from the vascular endothelial cells, leading to repression of the blood pressure rise seen with advancing age.

Comparative cytotoxicity of cisplatin, sodium selenite and selenium-cisplatin conjugate [(NH3)2Pt(SeO3)]; changes of blood platelet activation

The cytotoxic effects of a novel compound, conjugate Se-Pt [(NH3)2Pt (SeO3)] on blood platelet function (aggregation, release of adenine nucleotides) were studied. Contrary to the action of cisplatin or selenite alone, [(NH3)2Pt(SeO3)] did not inhibit ADP-induced platelet aggregation, thrombin-induced release of adenine nucleotides from platelets, and had no effect on the metabolism of platelet arachidonate. The tested compound seems to be less toxic than cisplatin alone, and has no effect on blood platelet activation.

[Microhemodynamics and energy metabolism in schizophrenia patients]

An apparent disturbance was revealed in microhaemodynamics of patients diagnosed as having schizophrenia (n = 210) which was more pronounced in continuously progredient form of the above medical condition. An increase in conjunctival indexes, polymorphic character of capillaries, decrease in numbers of capillary loops were revealed by biomicroscopy of the bulbar conjunctiva and capillaroscopy respectively. The patients showed lowering of ATP level and rise in the content of cathodic LDG4-LDG5 fractions, accumulation in blood of lactic and pyruvic acids.

Determination of adenosine phosphates in whole blood by capillary zone electrophoresis

The pool of chemical energy in an organism represented by high-energy compounds can be assessed by means of adenosine triphosphate (ATP) determination in whole blood and tissues. The elegant manner for the determination of adenosine phosphates (ATP, ADP, AMP) in a single assay is offered by the technique of capillary zone electrophoresis. For this purpose, the BioFocus 3000 Capillary Electrophoresis System (BIO-RAD Laboratories, Inc., Hercules, CA, USA) was used. For the construction of calibration curves, pure preparations of ATP, ADP and AMP were analyzed. The method was used for adenosine phosphates determination in the umbilical blood samples from physiological and immature newborns. Capillary zone electrophoresis enables a specific and simultaneous determination of adenosine phosphates and, thus, monitoring of unusual metabolic situations.