Mediators of histamine release from human platelets, lymphocytes, and granulocytes

Lysates of mixed human leukocyte suspensions released histamine from intact human leukocytes in vitro. Microgram quantities of leukocyte lysate protein released up to 90% of the total available histamine. The mixed leukocyte lysates were separated by differential centrifugation into nuclear (800 g pellet), lysosomal (25,000 g pellet), and postlysosomal supernatant (25,000 g supernatant) fractions. The degree of separation of the lysosomal from the other two fractions was assessed by measuring the relative activities of four lysosomal enzymes. The average distribution of enzyme activity was 11 +/-2% (mean +/-1 SD), 72 +/-10%, and 17 +/-8% for the nuclear, lysosomal, and supernatant fractions respectively. The histamine-releasing activity was equally distributed between the lysosomal and supernatant fractions, each of which had 5-fold greater activity than the nuclear fraction.Purified suspensions of platelets, lymphocytes, and granulocytes were prepared, and the lysates of these suspensions all had histamine-releasing activity. Centrifugation at 100,000 g for 18 hr sedimented the histamine-releasing activity from all three types of lysate. After 20% ethanol fractionation for the preparation of cationic protein, only the activity from the platelet lysates was found in the 20% ethanol insoluble fraction.These mediators of histamine release from human platelets, lymphocytes, and granulocytes may play a role in the development of the vasodilation and increased vascular permeability which characterize the acute inflammatory response.     

Effects of sorbinil treatment on erythrocytes and platelets of persons with diabetes

Thirty-three diabetic subjects were given the aldose reductase inhibitor sorbinil (Pfizer, UK) for 3 wk. There was a significant fall in mean erythrocyte sorbitol concentration over this period. In all subjects erythrocyte sorbitol concentrations after treatment were within or below the range found in normal subjects. No changes in erythrocyte 2,3-diphosphoglycerate (2,3-DPG) or myo-inositol concentrations, plasma beta-thromboglobulin (beta-TG) concentration, or P50--a measure of the oxygen affinity of hemoglobin--were observed. There was a high incidence of adverse reactions to the drug.     

Effects of X-ray radiation on the rheologic properties of platelets and lymphocytes

BACKGROUND: Blood is often irradiated before transfusion for severely immunocompromised patients to prevent a potentially fatal complication of transfusion-associated GVHD. STUDY DESIGN AND METHODS: This study evaluates the effects of X-ray radiation on platelet and lymphocyte rheology because the ability of these blood cells to deform is vital to their flow throughout the microvascular system. Micropipette aspiration experiments were conducted on platelets and lymphocytes exposed to X-ray radiation doses of 0 (control), 25, and 50 Gy. RESULTS: A significant increase in the Young modulus of elasticity was observed between control platelets and irradiated platelets at 25 Gy (p = 0.02) and 50 Gy (p = 0.03). Percent cell activation increased significantly in 25 Gy-irradiated platelets (p = 0.008). In addition, lymphocytes irradiated at 25 Gy have a higher viscosity than controls (p < 0.02). A significantly larger number of activated cells is found in the 50 Gy-irradiated lymphocyte population (p < 0.04). CONCLUSION: The changes in the deformability and activation of irradiated platelets and lymphocytes may reduce local blood flow and lead to intermittent blockage, which may cause a change of blood flow in microvasculatures.     

Effects of hormone replacement therapy on blood platelets

BACKGROUND: Hormone replacement therapy (HRT) increases the risk of cardiovascular morbidity in postmenopausal women under certain circumstances. Part of this effect may be the result of the influence of HRT on blood platelets. We studied the effect of short-term oral hormone replacement therapy (unopposed oestradiol or sequentially combined oestradiol and trimegestone or dydrogesterone) on platelet activation parameters in healthy postmenopausal women. DESIGN: We designed a prospective, randomised, placebo-controlled 12-week study. Sixty healthy, normotensive, nonhysterectomised, postmenopausal women received daily micronised oestradiol (E2) 2 mg (n = 16), or 2 mg E2 daily sequentially combined with either trimegestone 0.5 mg daily (n = 14) or dydrogesterone 10 mg daily (n = 14), or placebo (n = 16). Data on platelet activation were collected at baseline and after 12 weeks of treatment using flow cytometry. RESULTS: Twelve weeks of treatment with combined HRT was associated with an increase in platelet activation parameters P-selectin and glycoprotein 53 (by 17% and 14%, respectively, P = 0.04 vs. the placebo group for both comparisons), suggesting alpha granule and lysosome degranulation. E2 replacement therapy was associated with an increase in P-selectin labelling by 22% (P = 0.04 vs. the placebo group). CONCLUSION: Short-term treatment with oestradiol or combined HRT increases the amount of circulating activated platelets as measured by flow cytometry. This could be a mechanism by which short-term HRT might increase the risk of thrombosis.     

Glutathione peroxidase activity, selenium and lipid peroxides levels in blood of cancer children

The concentrations of whole blood and plasma selenium, plasma lipid peroxides and the glutathione peroxidase activity in plasma and erythrocytes were measured in untreated and treated children with neuro- (n = 23) and nephroblastoma (n = 32) aged 6 months to 15 years. The patients were divided into the following groups: 0.5-1, 1-3, 3.5-6 and 8-15 years old. In all the groups of cancer patients investigated selenium concentration in whole blood and plasma and glutathione peroxidase activity in erythrocytes and plasma were significantly lower than in the age-matched healthy children. The concentrations of lipid peroxides in plasma of children with cancer was higher than in the age-matched control group. No differences were observed between the levels of the determined parameters in children with neuro- and nephroblastoma. Nor were there any differences in the determined parameters between children before and during treatment with cytostatics and between children at different stages of the disease. A significant linear correlation was found between plasma selenium concentration and glutathione peroxidase activity in the erythrocytes and plasma of children with cancer.     

Differential sensitivity of peripheral blood granulocytes, monocytes, and lymphocytes to endotoxin-induced apoptosis in patients who have sustained Salmonella infection

The differential sensitivity of peripheral blood granulocytes, monocytes, and lymphocytes to endotoxin-induced apoptosis was studied in convalescents with Salmonella infection. The number of early (Tunel+PI-) and late (Tunel+PI+) apoptotic cells and the rate of apoptosis (the relative content of DNA apoptotic fragments in the solitary cell) were determined on a FACSCalibur cytofluorometer, by applying a package of the CellQuest programs (Becton Dickinson). A higher threshold of sensitivity of granulocytes, monocytes, and lymphocytes to the apoptotic effect of low, suboptimal doses (100 ng), as well as suppression of early stages of apoptosis by the optimal doses (1000 ng) of S. enteritidis lypopolysaccharides (LPS) were observed in patients who had sustained salmonellosis at a stage of reconvalescence. The hierarchy of LPS-induced apoptosis (granulocyte--monocyte--lymphocyte), observed in healthy donors, was also retained in the group of patients receiving the suboptimal doses of LPS, which seems to be associated with the repeated action of toxin on sensitized cell populations.     

Simultaneous analysis of coenzyme Q10 in plasma, erythrocytes and platelets: comparison of the antioxidant level in blood cells and their environment in healthy children and after oral supplementation in adults

BACKGROUND: Coenzyme Q10 (CoQ10) originates from food intake as well as from endogenous synthesis. While plasma concentrations may be influenced by dietary uptake, little is known whether concentrations in plasma reflect or influence intracellular concentrations. METHODS: For clinical routine investigation of intracellular CoQ10 contents, blood erythrocytes and platelets were isolated by Ficoll separating solution and CoQ10 analysed using HPLC. The intracellular concentrations were compared to environmental plasma concentrations of 50 clinically healthy infants and additionally after exogenous pharmaceutical supplementation of CoQ10 (3 mg/kg/day) to 12 adult probands for 14 days. RESULTS: In healthy children, no correlation between plasma concentration and content in blood cells was found. A negative correlation exists between the year of life of the infants and CoQ10 concentrations in plasma correlated to cholesterol content. Probands supplemented with CoQ10 showed a distinct response in plasma concentrations after 14 days. While excessive environmental supplementation was without influence on erythrocyte concentrations, a positive correlation exists between plasma content and concentrations in platelets as mitochondria containing cell lines. CONCLUSIONS: Under physiologically normal conditions, blood cells or organs may regulate their CoQ10 content independently from environmental supply. Effects may be expected in situations of deficiency or excessive supply. Erythrocyte concentration of CoQ10 keeps independent from environmental supply. Thus incorporation into outer cell membranes may be limited. However, an excessive environmental supply may influence inner compartments like mitochondrial membranes.     

Determination of zinc in erythrocytes, granulocytes and serum by flame atomic absorption spectrophotometry

Zinc was determined in granulocytes, erythrocytes and serum by flame atomic absorption spectrophotometry. Using a Teflon sampling cup, the sample volume for a single granulocyte zinc determination was reduced to 100 microliter. Zinc in serum and erythrocytes was measured by aspirating the sample at a rate of 5 ml/min. The total volume of blood used was 23-28 ml. The intra-assay coefficient of variation of the method for granulocytes was 0.01 and of the method for serum and erythrocytes 0.018. The corresponding inter-assay coefficient of variation was 0.037 and 0.03, respectively. Recovery of zinc determined by the method of aspirating the small volume (100 microliter) was 103% and by the method of aspirating 5 ml/min 97%. The coefficient of correlation between the two methods was r = 0.9968.     

Comparison of ascorbic acid concentrations in granulocytes and lymphocytes

The author measured the ascorbic acid concentration (microgram/10(8) cells) in leukocytes from fourteen healthy male subjects aged 20 to 28 years. The mean values were 10.9 (range 3.7 to 15.8) in granulocytes and 88.5 (range 35.3 to 122.2) in lymphocytes. These findings suggest that ascorbic acid metabolism in lymphocytes differs from that in granulocytes. In the second experiments the changes in ascorbic acid concentrations were measured in the course of an ascorbic acid loading test to a 33-year-old healthy male volunteer, in which increasing doses (1, 3, 5, 10 g/day X 7 days) were weekly loaded for 4 successive weeks and the ascorbic acid concentrations were examined at the end of each week. As the loading dose increased, ascorbic acid concentration in lymphocytes decreased during the 4 week period while the counterpart value in granulocytes stayed essentially constant. The present findings suggest the differences in ascorbic acid metabolism between granulocytes and lymphocytes.     

Effect of indomethacin on basic parameters of gastric secretion, aggregative activity of blood platelets and fibrinolysis

Indomethacin at a therapeutic dose of 50 mg causes a significant increase in the basal and histamine-stimulated acid and pepsin secretion, a decrease in bicarbonate production, the suppression of ADP-induced platelet aggregation and antiaggregational activity of the vascular epithelium, and intensification of fibrinolysis at the expense of activation of its first phase. These effects determined by the blockade of prostaglandin cyclooxygenase, can contribute to the development of erosive-ulcerative hemorrhagic lesions of the gastroduodenal mucosa. The sensitivity of different people to indomethacin varies within broad limits. A study of a response of the thromboxan-prostacycline system to the drug administration can serve for objective assessment of individual drug tolerance, prognosis of complications and a choice of an effective therapeutic scheme.     

The specific distribution of erythrocytes and blood platelets according to the volume of cells in different-age children

The reference volumes of erythrocytes and blood platelets were evaluated for different age groups of children. The mean volume of cells and the parameters of its distribution, i.e. SD, As and Ex, were found. The mean volume of erythrocytes and the value of positive Ex for the volume of blood platelets were shown to be reliably higher in adults. The investigated blood parameters in children were proven to depend in children on their age and sex. It was concluded that the mentioned peculiarities should be considered in the practice of clinical laboratory examinations.     

Glutathione peroxidase activity, lipid peroxides and selenium status in blood in patients with Down's syndrome

The concentrations of selenium and lipid peroxides and the catalytic activity of glutathione peroxidase were measured in the blood of 6 children (6-16 years of age) and 8 adults (17-27 years old) with Down's syndrome (trisomy 21). The values were compared with those for a control group of age-matched normal people. The selenium concentration in whole blood, erythrocytes and plasma was significantly lower in trisomy 21 patients than in normal subjects (p less than 0.001) in both age groups. No statistically significant differences were observed in selenium concentration in whole blood, erythrocytes and plasma between children and adults in the Down's syndrome group. Glutathione peroxidase catalytic activity in erythrocytes was significantly higher in Down's syndrome children than in healthy children (p less than 0.001). Plasma glutathione peroxidase catalytic activity in both investigated age groups was statistically considerably lower in the Down's syndrome patient group. The concentration of lipid peroxides, expressed as the malondialdehyde concentration, is lower in Down's syndrome patients. No correlation between selenium concentration, glutathione peroxidase catalytic activity and amount of lipid peroxides was found in the trisomy 21 patient group.     

Effects of inorganic nitrates on thyroid gland activity and morphology in female rats

The present study was undertaken to determine the effects of intake of inorganic nitrates in drinking water on thyroid gland activity and morphology in female rats. During 5 months of treatment, nitrates 50, 150 and 500 mg/L induced a significant dose-dependent decrease in bodyweight gain, compared with the control rats. At the end of the experiment, nitrates 150 and 500 mg/L induced hypertrophy of the thyroid gland, accompanied by an increase in the size of the thyroid follicles and hyposecretion of thyroid hormones T3 (triiodothyronine) and T4 (tetraiodothyronine). We concluded that a high nitrate intake in water influenced thyroid gland activity and morphology and might be considered to be a goitrogenic factor.